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Sample records for lwir radiative properties

  1. Radiation calibration for LWIR Hyperspectral Imager Spectrometer

    Science.gov (United States)

    Yang, Zhixiong; Yu, Chunchao; Zheng, Wei-jian; Lei, Zhenggang; Yan, Min; Yuan, Xiaochun; Zhang, Peizhong

    2014-11-01

    The radiometric calibration of LWIR Hyperspectral imager Spectrometer is presented. The lab has been developed to LWIR Interferometric Hyperspectral imager Spectrometer Prototype(CHIPED-I) to study Lab Radiation Calibration, Two-point linear calibration is carried out for the spectrometer by using blackbody respectively. Firstly, calibration measured relative intensity is converted to the absolute radiation lightness of the object. Then, radiation lightness of the object is is converted the brightness temperature spectrum by the method of brightness temperature. The result indicated †that this method of Radiation Calibration calibration was very good.

  2. Internal and external stray radiation suppression for LWIR catadioptric telescope using non-sequential ray tracing

    Science.gov (United States)

    Zhu, Yang; Zhang, Xin; Liu, Tao; Wu, Yanxiong; Shi, Guangwei; Wang, Lingjie

    2015-07-01

    A long wave infrared imaging system operated for space exploration of faint target is highly sensitive to stray radiation. We present an integrative suppression process of internal and external stray radiation. A compact and re-imaging LWIR catadioptric telescope is designed as practical example and internal and external stray radiation is analyzed for this telescope. The detector is cryogenically cooled with 100% cold shield efficiency of Lyot stop. A non-sequential ray tracing technique is applied to investigate how the stray radiation propagates inside optical system. The simulation and optimization during initial design stage are proceeded to avoid subversive defect that the stray radiation disturbs the target single. The quantitative analysis of stray radiation irradiance emitted by lenses and structures inside is presented in detail. The optical elements, which operate at room-temperature due to the limitation of weight and size, turn to be the significant stray radiation sources. We propose a method combined infrared material selection and optical form optimization to reduce the internal stray radiation of lens. We design and optimize mechanical structures to achieve a further attenuation of internal stray radiation power. The point source transmittance (PST) is calculated to assess the external radiation which comes from the source out of view field. The ghost of bright target due to residual reflection of optical coatings is simulated. The results show that the performance of stray radiation suppression is dramatically improved by iterative optimization and modification of optomechanical configurations.

  3. Influence of Size of Source Effect on Accuracy of LWIR Radiation Thermometers

    Directory of Open Access Journals (Sweden)

    Cywiak David

    2016-12-01

    Full Text Available Determining the size of source effect of a radiation thermometer is not an easy task and manufacturers of these thermometers usually do not indicate the deviation to the measured temperature due to this effect. It is one of the main uncertainty components when measuring with a radiation thermometer and it may lead to erroneous estimation of the actual temperature of the measured target. We present an empiric model to estimate the magnitude of deviation of the measured temperature with a long-wavelength infrared radiation thermometer due to the size of source effect. The deviation is calculated as a function of the field of view of the thermometer and the diameter of the radiating source. For thermometers whose field of view size at 90% power is approximately equal to the diameter of the radiating source, it was found that this effect may lead to deviations of the measured temperature of up to 6% at 200ºC and up to 14% at 500ºC. Calculations of the temperature deviation with the proposed model are performed as a function of temperature and as a function of the first order component of electrical signal.

  4. 长波红外高光谱成像光谱仪的辐射定标%Study of Radiation Calibration for LWIR Hyperspectral Imager Spectrometer

    Institute of Scientific and Technical Information of China (English)

    袁小春; 杨智雄; 余春超; 郑为建; 雷正刚; 严敏

    2015-01-01

    Infrared radiometric calibration is of critical importance for information quantification of remote sensing of environment in infrared spectrum. In the quantitative analysis, the calibration of the measured spectra is very imporant. LWIR Interferometric Hyperspectral imager Spectrometer Prototype(CHIPED-I) is developed for studying Radiation Calibration. Two-point linear calibration method is carried out for the spectrometer by using blackbody respectively. Firstly, relative intensity is converted to the absolute radiation lightness of the object. Then, radiation intensity of the object is converted into the brightness temperature spectrum by the method of brightness temperature. The result indicats that such method of Radiation Calibration calibration is very good , which is of significance to the further analysis of atmospheric transmission and the retrieval of the concentration of infrared active gas in atmosphere.%红外辐射定标是红外遥感信息定量化的关键技术,对所测光谱进行定标是定量分析中的重要环节。采用自行研制长波红外高光谱成像光谱仪原理实验装置(简称 CHIPED-I)进行验证,用黑体对实验装置进行了两点线性定标,将测量的相对强度转化成目标的绝对辐射亮度谱,采用亮温法算出标定后的亮温光谱。结果表明,这种辐射定标方法用于长波红外高光谱成像光谱仪方法可行,这对进一步分析大气透过率和反演大气中红外活性气体浓度具有实际意义。

  5. Properties of undulator radiation

    Energy Technology Data Exchange (ETDEWEB)

    Veal, B.W.

    1985-11-01

    Properties of the radiation emitted by a plane sinusoidal undulator are calculated in the far field approximation. Software has been developed to calculate the spectral distribution and polarization of the radiated intensity I(E) at a point on (or integrated over) a cross sectional observation plane of the photon beam. Spatial distribution of monochromatic radiation and power density contours are also calculated. Spectral broadening caused by an electron beam of finite spatial distribution is considered. Dispersive properties of the photon beam, including the dependence on deflection parameter, are analyzed. It is shown that reasonably constant intensity distribution I(E) can be obtained by properly shaping the beam acceptance aperture. 5 refs., 11 figs.

  6. Total electron count variability and stratospheric ozone effects on solar backscatter and LWIR emissions

    Science.gov (United States)

    Ross, John S.; Fiorino, Steven T.

    2017-05-01

    The development of an accurate ionospheric Total Electron Count (TEC) model is of critical importance to high frequency (HF) radio propagation and satellite communications. However, the TEC is highly variable and is continually influenced by geomagnetic storms, extreme UV radiation, and planetary waves. Being able to capture this variability is essential to improve current TEC models. The growing body of data involving ionospheric fluctuations and stratospheric variations has revealed a correlation. In particular, there is a marked and persistent association between increases in stratospheric ozone and variability of the TEC. The spectral properties of ozone show that it is a greenhouse gas that alters long wave emissions from Earth and interacts with the UV spectrum coming from the sun. This study uses the Laser Environment Effects Definition and Reference (LEEDR) radiative transfer and atmospheric characterization code to model the effects of changes in stratospheric ozone on solar backscatter and longwave (LWIR) terrestrial emissions and infer TEC and TEC variability.

  7. Dead pixel replacement in LWIR microgrid polarimeters.

    Science.gov (United States)

    Ratliff, Bradley M; Tyo, J Scott; Boger, James K; Black, Wiley T; Bowers, David L; Fetrow, Matthew P

    2007-06-11

    LWIR imaging arrays are often affected by nonresponsive pixels, or "dead pixels." These dead pixels can severely degrade the quality of imagery and often have to be replaced before subsequent image processing and display of the imagery data. For LWIR arrays that are integrated with arrays of micropolarizers, the problem of dead pixels is amplified. Conventional dead pixel replacement (DPR) strategies cannot be employed since neighboring pixels are of different polarizations. In this paper we present two DPR schemes. The first is a modified nearest-neighbor replacement method. The second is a method based on redundancy in the polarization measurements.We find that the redundancy-based DPR scheme provides an order-of-magnitude better performance for typical LWIR polarimetric data.

  8. Radiative properties of dense nanofluids.

    Science.gov (United States)

    Wei, Wei; Fedorov, Andrei G; Luo, Zhongyang; Ni, Mingjiang

    2012-09-01

    The radiative properties of dense nanofluids are investigated. For nanofluids, scattering and absorbing of electromagnetic waves by nanoparticles, as well as light absorption by the matrix/fluid in which the nanoparticles are suspended, should be considered. We compare five models for predicting apparent radiative properties of nanoparticulate media and evaluate their applicability. Using spectral absorption and scattering coefficients predicted by different models, we compute the apparent transmittance of a nanofluid layer, including multiple reflecting interfaces bounding the layer, and compare the model predictions with experimental results from the literature. Finally, we propose a new method to calculate the spectral radiative properties of dense nanofluids that shows quantitatively good agreement with the experimental results.

  9. Uncooled LWIR imaging: applications and market analysis

    Science.gov (United States)

    Takasawa, Satomi

    2015-05-01

    The evolution of infrared (IR) imaging sensor technology for defense market has played an important role in developing commercial market, as dual use of the technology has expanded. In particular, technologies of both reduction in pixel pitch and vacuum package have drastically evolved in the area of uncooled Long-Wave IR (LWIR; 8-14 μm wavelength region) imaging sensor, increasing opportunity to create new applications. From the macroscopic point of view, the uncooled LWIR imaging market is divided into two areas. One is a high-end market where uncooled LWIR imaging sensor with sensitivity as close to that of cooled one as possible is required, while the other is a low-end market which is promoted by miniaturization and reduction in price. Especially, in the latter case, approaches towards consumer market have recently appeared, such as applications of uncooled LWIR imaging sensors to night visions for automobiles and smart phones. The appearance of such a kind of commodity surely changes existing business models. Further technological innovation is necessary for creating consumer market, and there will be a room for other companies treating components and materials such as lens materials and getter materials and so on to enter into the consumer market.

  10. High spatial resolution LWIR hyperspectral sensor

    Science.gov (United States)

    Roberts, Carson B.; Bodkin, Andrew; Daly, James T.; Meola, Joseph

    2015-06-01

    Presented is a new hyperspectral imager design based on multiple slit scanning. This represents an innovation in the classic trade-off between speed and resolution. This LWIR design has been able to produce data-cubes at 3 times the rate of conventional single slit scan devices. The instrument has a built-in radiometric and spectral calibrator.

  11. Radiative properties of ice clouds

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, D.L.; Koracin, D.; Carter, E. [Desert Research Institute, Reno, NV (United States)

    1996-04-01

    A new treatment of cirrus cloud radiative properties has been developed, based on anomalous diffraction theory (ADT), which does not parameterize size distributions in terms of an effective radius. Rather, is uses the size distribution parameters directly, and explicitly considers the ice particle shapes. There are three fundamental features which characterize this treatment: (1) the ice path radiation experiences as it travels through an ice crystal is parameterized, (2) only determines the amount of radiation scattered and absorbed, and (3) as in other treatments, the projected area of the size distribution is conserved. The first two features are unique to this treatment, since it does not convert the ice particles into equivalent volume or area spheres in order to apply Mie theory.

  12. LWIR Microgrid Polarimeter for Remote Sensing Studies

    Science.gov (United States)

    2010-02-28

    Polarimeter for Remote Sensing Studies 5b. GRANT NUMBER FA9550-08-1-0295 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 1. Scott Tyo 5e. TASK...and tested at the University of Arizona, and preliminary images are shown in this final report. 15. SUBJECT TERMS Remote Sensing , polarimetry 16...7.0 LWIR Microgrid Polarimeter for Remote Sensing Studies J. Scott Tyo College of Optical Sciences University of Arizona Tucson, AZ, 85721 tyo

  13. LWIR pupil imaging and longer-term calibration stability

    Science.gov (United States)

    LeVan, Paul D.; Sakoglu, Ünal

    2016-09-01

    A previous paper described LWIR pupil imaging, and an improved understanding of the behavior of this type of sensor for which the high-sensitivity focal plane array (FPA) operated at higher flux levels includes a reversal in signal integration polarity. We have since considered a candidate methodology for efficient, long-term calibration stability that exploits the following two properties of pupil imaging: (1) a fixed pupil position on the FPA, and (2) signal levels from the scene imposed on significant but fixed LWIR background levels. These two properties serve to keep each pixel operating over a limited dynamic range that corresponds to its location in the pupil and to the signal levels generated at this location by the lower and upper calibration flux levels. Exploiting this property for which each pixel of the Pupil Imager operates over its limited dynamic range, the signal polarity reversal between low and high flux pixels, which occurs for a circular region of pixels near the upper edges of the pupil illumination profile, can be rectified to unipolar integration with a two-level non-uniformity correction (NUC). Images corrected real-time with standard non-uniformity correction (NUC) techniques, are still subject to longer-term drifts in pixel offsets between recalibrations. Long-term calibration stability might then be achieved using either a scene-based non-uniformity correction approach, or with periodic repointing for off-source background estimation and subtraction. Either approach requires dithering of the field of view, by sub-pixel amounts for the first method, or by large off-source motions outside the 0.38 milliradian FOV for the latter method. We report on the results of investigations along both these lines.

  14. Detection of Unexploded Ordnance Using Airborne LWIR Emissivity Signatures

    Science.gov (United States)

    2015-11-25

    pixels [7]. A LWIR emissivity library was built using the FSR laboratory spectra and re-sampled to the LWIR Hypercam wavelengths (850 to 1225... SVD ) [10], which results in a descending ordering of the basis vectors. 3. RESULTS Figure 2 shows detection results for: (a) painted projectiles, (b

  15. Classifying objects in LWIR imagery via CNNs

    Science.gov (United States)

    Rodger, Iain; Connor, Barry; Robertson, Neil M.

    2016-10-01

    The aim of the presented work is to demonstrate enhanced target recognition and improved false alarm rates for a mid to long range detection system, utilising a Long Wave Infrared (LWIR) sensor. By exploiting high quality thermal image data and recent techniques in machine learning, the system can provide automatic target recognition capabilities. A Convolutional Neural Network (CNN) is trained and the classifier achieves an overall accuracy of > 95% for 6 object classes related to land defence. While the highly accurate CNN struggles to recognise long range target classes, due to low signal quality, robust target discrimination is achieved for challenging candidates. The overall performance of the methodology presented is assessed using human ground truth information, generating classifier evaluation metrics for thermal image sequences.

  16. 2-Cam LWIR imaging Stokes polarimeter

    Science.gov (United States)

    Kudenov, Michael W.; Dereniak, Eustace L.; Pezzaniti, Larry; Gerhart, Grant R.

    2008-04-01

    A 2-Cam micro-bolometer imaging polarimeter operating in the LWIR is presented. The system is capable of snapshot imaging Stokes polarimetry in any one channel (S I, S II, or S 3) by taking two simultaneous measurements of a scene. For measurements of S I or S II, the instrument relies on a specially optimized wire-grid beam-splitter. For measurements of S 3, a form birefringent quarter-wave retarder is inserted into the optical path. Specifics associated with the design of the wire-grid beam-splitter and the form birefringent quarter-wave retarder will be overviewed, with inclusion of RCWA simulations. Calibration and simulation procedures, as well as calibration targets, will be highlighted, and initial data from the instrument are presented.

  17. Type II superlattice technology for LWIR detectors

    Science.gov (United States)

    Klipstein, P. C.; Avnon, E.; Azulai, D.; Benny, Y.; Fraenkel, R.; Glozman, A.; Hojman, E.; Klin, O.; Krasovitsky, L.; Langof, L.; Lukomsky, I.; Nitzani, M.; Shtrichman, I.; Rappaport, N.; Snapi, N.; Weiss, E.; Tuito, A.

    2016-05-01

    SCD has developed a range of advanced infrared detectors based on III-V semiconductor heterostructures grown on GaSb. The XBn/XBp family of barrier detectors enables diffusion limited dark currents, comparable with MCT Rule-07, and high quantum efficiencies. This work describes some of the technical challenges that were overcome, and the ultimate performance that was finally achieved, for SCD's new 15 μm pitch "Pelican-D LW" type II superlattice (T2SL) XBp array detector. This detector is the first of SCD's line of high performance two dimensional arrays working in the LWIR spectral range, and was designed with a ~9.3 micron cut-off wavelength and a format of 640 x 512 pixels. It contains InAs/GaSb and InAs/AlSb T2SLs, engineered using k • p modeling of the energy bands and photo-response. The wafers are grown by molecular beam epitaxy and are fabricated into Focal Plane Array (FPA) detectors using standard FPA processes, including wet and dry etching, indium bump hybridization, under-fill, and back-side polishing. The FPA has a quantum efficiency of nearly 50%, and operates at 77 K and F/2.7 with background limited performance. The pixel operability of the FPA is above 99% and it exhibits a stable residual non uniformity (RNU) of better than 0.04% of the dynamic range. The FPA uses a new digital read-out integrated circuit (ROIC), and the complete detector closely follows the interfaces of SCD's MWIR Pelican-D detector. The Pelican- D LW detector is now in the final stages of qualification and transfer to production, with first prototypes already integrated into new electro-optical systems.

  18. An analysis of fusion algorithms for LWIR and visual images

    CSIR Research Space (South Africa)

    De Villiers, J

    2013-12-01

    Full Text Available fusion, he modified the red channel of the input image with the corre- sponding pixel value from the LWIR image. Li et. al. [6] used a similar channel-based fusion method to Zheng, however they also changed the colour space of the image to Y CBCR... and weighted those values using the LWIR value and then modified the fused image to look similar to a separate sample image. This work uses pixel-level fusion, since the fastest possible fusion method was required. Since the input visual images are colour each...

  19. Minority carrier lifetimes in different doped LWIR HgCdTe grown by LPE

    Science.gov (United States)

    Qiu, GuangYin; Wei, YanFeng; Sun, QuanZhi; Yang, JianRong

    2012-10-01

    The carrier lifetimes of different types of p-type doped HgCdTe(x~0.23) long wavelength infrared (LWIR) epilayers were measured which were Hg-vacancy, Au and arsenic doped ones prepared by Te-rich Liquid-phase epitaxy (LPE). By comparing the lifetimes of Hg-vacancy and extrinsic doped HgCdTe, we focus on three primary mechanisms limiting the lifetimes in these different p-type HgCdTe samples: radiative recombination, Auger recombination and Schokley-Read- Hall (SRH) Recombination. The recombination mechanism in p-type HgCdTe is the SRH recombination at low temperatures and Auger and radiative recombination at high temperature. It is found that the lifetime of As-doped and Au-doped HgCdTe is far longer than that of Hg-vacancy-doped sample which is caused by the deep energy level of the Hg-vacancy acceptor that is considered as a recombination center in HgCdTe. Also we found lifetime in those p-type doped HgCdTe LWIR epilayers is limited by SRH by comparing the experimental lifetimes with the calculated data. Impurity doping was found to have a main effect on minority carrier lifetime.

  20. Thermal Radiative Properties of Xonotlite Insulation Material

    Institute of Scientific and Technical Information of China (English)

    Xinxin ZHANG; Gaosheng WEI; Fan YU

    2005-01-01

    This paper presents experimental results of thermal radiative properties of xonotlite-type calcium silicate insulation material. Transmittance spectra were first taken using Fourier transform infrared spectrometer (FTIR)for the samples with ρ = 234 kg/m3. Specific extinction coefficient spectra were then obtained by applying Beer's law.Finally,by using the diffusion approximation,the specific Rossland mean extinction coefficients and radiative thermal conductivities were obtained for various temperatures. The results show that the specific spectral extinction coefficient of xonotlite is larger than 7 m2/kg in the whole measured spectra, and diffusion approximation equation is a reasonable description of radiative heat transfer in xonotlite insulation material. The specific Rossland mean extinction coefficient of xonotlite has a maximum ualue at 400 K and the radiative thermal conductivity is almost proportional to the cube of temperature.

  1. Cloud radiative properties and aerosol - cloud interaction

    Science.gov (United States)

    Viviana Vladutescu, Daniela; Gross, Barry; Li, Clement; Han, Zaw

    2015-04-01

    The presented research discusses different techniques for improvement of cloud properties measurements and analysis. The need for these measurements and analysis arises from the high errors noticed in existing methods that are currently used in retrieving cloud properties and implicitly cloud radiative forcing. The properties investigated are cloud fraction (cf) and cloud optical thickness (COT) measured with a suite of collocated remote sensing instruments. The novel approach makes use of a ground based "poor man's camera" to detect cloud and sky radiation in red, green, and blue with a high spatial resolution of 30 mm at 1km. The surface-based high resolution photography provides a new and interesting view of clouds. As the cloud fraction cannot be uniquely defined or measured, it depends on threshold and resolution. However as resolution decreases, cloud fraction tends to increase if the threshold is below the mean, and vice versa. Additionally cloud fractal dimension also depends on threshold. Therefore these findings raise concerns over the ability to characterize clouds by cloud fraction or fractal dimension. Our analysis indicate that Principal Component analysis may lead to a robust means of quantifying cloud contribution to radiance. The cloud images are analyzed in conjunction with a collocated CIMEL sky radiometer, Microwave Radiometer and LIDAR to determine homogeneity and heterogeneity. Additionally, MFRSR measurements are used to determine the cloud radiative properties as a validation tool to the results obtained from the other instruments and methods. The cloud properties to be further studied are aerosol- cloud interaction, cloud particle radii, and vertical homogeneity.

  2. MidIR and LWIR polarimetric sensor comparison study

    Science.gov (United States)

    Gurton, Kristan; Felton, Melvin; Mack, Robert; LeMaster, Daniel; Farlow, Craig; Kudenov, Michael; Pezzaniti, Larry

    2010-04-01

    We present a comparative study involving five distinctly different polarimetric imaging platforms that are designed to record calibrated Stokes images (and associated polarimetric products) in either the MidIR or LWIR spectral regions. The data set used in this study was recorded during April 14-18, 2008, at the Russell Tower Measurement Facility, Redstone Arsenal, Huntsville, AL. Four of the five camera systems were designed to operate in the LWIR (approx. 8-12μm), and used either cooled mercury cadmium telluride (MCT) focal-plane-arrays (FPA), or a near-room temperature microbolometer. The lone MidIR polarimetric sensor was based on a liquid nitrogen (LN2) cooled indium antimonide (InSb) FPA, resulting in an approximate wavelength response of 3-5μm. The selection of cameras was comprised of the following optical designs: a LWIR "super-pixel," or division-of-focal plane (DoFP) sensor; two LWIR spinning-achromatic-retarder (SAR) based sensors; one LWIR division-of-amplitude (DoAM) sensor; and one MidIR division-of-aperture (DoA) sensor. Cross-sensor comparisons were conducted by examining calibrated Stokes images (e.g., S0, S1, S2, and degree-of-linear polarization (DOLP)) recorded by each sensor for a given target at approximately the same test periods to ensure that data sets were recorded under similar atmospheric conditions. Target detections are applied to the image set for each polarimetric sensor for further comparison, i.e., conventional receiver operating characteristic (ROC) curve analysis and an effective contrast ratio are considered.

  3. Modeling radiative properties of nanoscale patterned wafers

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Temperature nonuniformity in rapid thermal processing of wafers is a critical problem facing the semiconductor industry. One cause of the problem is the nonuniform absorption of thermal radiation in patterned wafers where the optical properties vary across the wafer surface. This paper presents a parametric study of the radiative properties of patterned wafers, considering the effect of temperature, wavelength, and polarization. The finite-difference time-domain (FDTD) method is employed to examine the effect of various trench sizes on the radiative properties via numerically solving the Maxwell equations. The effective medium theory (EMT) is also used to help explain the absorptance prediction. The results show that in the cases with trench size variation, the resonance cavity effect may increase the absorptance as the trench width increases. And in the cases with trench size increasing at several different filling ratios, the absorptance does not change much at small filling ratio. The effects of the resonant cavity, diffraction, wave interferences on the spectral-directional absorptance were also discussed. This work is of great importance for optimization of advanced annealing techniques in semiconductor manufacturing.

  4. Architectural Analysis of a LLNL LWIR Sensor System

    Energy Technology Data Exchange (ETDEWEB)

    Bond, Essex J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Curry, Jim R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); LaFortune, Kai N. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Williams, Alicia M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2013-11-26

    The architecture of an LLNL airborne imaging and detection system is considered in this report. The purpose of the system is to find the location of substances of interest by detecting their chemical signatures using a long-wave infrared (LWIR) imager with geo-registration capability. The detection system consists of an LWIR imaging spectrometer as well as a network of computer hardware and analysis software for analyzing the images for the features of interest. The system has been in the operations phase now for well over a year, and as such, there is enough use data and feedback from the primary beneficiary to assess the current successes and shortcomings of the LWIR system architecture. LWIR system has been successful in providing reliable data collection and the delivery of a report with results. The weakness of the architecture has been identified in two areas: with the network of computer hardware and software and with the feedback of the state of the system health. Regarding the former, the system computers and software that carry out the data acquisition are too complicated for routine operations and maintenance. With respect to the latter, the primary beneficiary of the instrument’s data does not have enough metrics to use to filter the large quantity of data to determine its utility. In addition to the needs in these two areas, a latent need of one of the stakeholders is identified. This report documents the strengths and weaknesses, as well as proposes a solution for enhancing the architecture that simultaneously addresses the two areas of weakness and leverages them to meet the newly identified latent need.

  5. Spacecraft Line-of-Sight Stabilization Using LWIR Earth Signature

    Science.gov (United States)

    Quadrelli, Marco B.; Piazzolla, Sabino

    2012-01-01

    The objective of this study is to investigate the potential of using the bright and near-uniform Earth infrared (or wavelength infrared, LWIR) signature as a stable reference for accurate (micro-rad or less) inertial pointing and tracking on-board an space vehicle, including the determination of the fundamental limits of applicability of the proposed method for space missions. We demonstrate sub-micro radian level pointing accuracy under a representative set of disturbances experienced by the spacecraft in orbit.

  6. Objects cloaking in LWIR region by using a high efficiency infrared pixel

    Directory of Open Access Journals (Sweden)

    Arab

    2016-12-01

    Full Text Available This article, introduces a new pixel which can emit infrared wavelengths from its surface and can be used for the purpose of cloaking objects from thermal cameras. This pixel can simulate the temperatures between 0 and 100ºC emited from an infrared radiation in LWIR (8-12 micrometres region. Nanocomposite material is used in the pixel structure and this has increased its capacities like ZT factor %40-50 better than the commercial material like Bi2Te3. Technical aspects of the pixel such as the emission wavelengths, rate of temperature changing, thermal contrast, ZT factor and so on are discussed in this paper and were determined by using thermography, non-contact thermometry, radiometry, four probe ac method and temperature differential

  7. Radiative torques: Analytical Model and Basic Properties

    CERN Document Server

    Lazarian, Alex

    2007-01-01

    We attempt to get a physical insight into grain alignment processes by studying basic properties of radiative torques (RATs). For this purpose we consider a simple toy model of a helical grain that reproduces well the basic features of RATs. The model grain consists of a spheroidal body with a mirror attached at an angle to it. Being very simple, the model allows analytical description of RATs that act upon it. We show a good correspondence of RATs obtained for this model and those of irregular grains calculated by DDSCAT. Our analysis of the role of different torque components for grain alignment reveals that one of the three RAT components does not affect the alignment, but induces only for grain precession. The other two components provide a generic alignment with grain long axes perpendicular to the radiation direction, if the radiation dominates the grain precession, and perpendicular to magnetic field, otherwise. We study a self-similar scaling of RATs as a function of $\\lambda/a_{eff}$. We show that th...

  8. Long wavelength infrared radiation thermometry for non-contact temperature measurements in gas turbines

    Science.gov (United States)

    Manara, J.; Zipf, M.; Stark, T.; Arduini, M.; Ebert, H.-P.; Tutschke, A.; Hallam, A.; Hanspal, J.; Langley, M.; Hodge, D.; Hartmann, J.

    2017-01-01

    The objective of the EU project "Sensors Towards Advanced Monitoring and Control of Gas Turbine Engines (acronym STARGATE)" is the development of a suite of advanced sensors, instrumentation and related systems in order to contribute to the developing of the next generation of green and efficient gas turbine engines. One work package of the project deals with the design and development of a long wavelength infrared (LWIR) radiation thermometer for the non-contact measurement of the surface temperature of thermal barrier coatings (TBCs) during the operation of gas turbine engines. For opaque surfaces (e.g. metals or superalloys) radiation thermometers which are sensitive in the near or short wavelength infrared are used as state-of-the-art method for non-contact temperature measurements. But this is not suitable for oxide ceramic based TBCs (e.g. partially yttria stabilized zirconia) as oxide ceramics are semi-transparent in the near and short wavelength infrared spectral region. Fortunately the applied ceramic materials are non-transparent in the long wavelength infrared and additionally exhibit a high emittance in this wavelength region. Therefore, a LWIR pyrometer can be used for non-contact temperature measurements of the surfaces of TBCs as such pyrometers overcome the described limitation of existing techniques. For performing non-contact temperature measurements in gas turbines one has to know the infrared-optical properties of the applied TBCs as well as of the hot combustion gas in order to properly analyse the measurement data. For reaching a low uncertainty on the one hand the emittance of the TBC should be high (>0.9) in order to reduce reflections from the hot surrounding and on the other hand the absorbance of the hot combustion gas should be low (<0.1) in order to decrease the influence of the gas on the measured signal. This paper presents the results of the work performed by the authors with focus on the implementation of the LWIR pyrometer and the

  9. On plasma radiative properties in stellar conditions

    CERN Document Server

    Turck-Chièze, S; Gilles, D; Loisel, G; Piau, L; 10.1016/j.hedp.2009.06.007

    2012-01-01

    The knowledge of stellar evolution is evolving quickly thanks to an increased number of opportunities to scrutinize the stellar internal plasma properties by stellar seismology and by 1D and 3D simulations. These new tools help us to introduce the internal dynamical phenomena in stellar modeling. A proper inclusion of these processes supposes a real confidence in the microscopic physics used, partly checked by solar or stellar acoustic modes. In the present paper we first recall which fundamental physics has been recently verified by helioseismology. Then we recall that opacity is an important ingredient of the secular evolution of stars and we point out why it is necessary to measure absorption coefficients and degrees of ionization in the laboratory for some well identified astrophysical conditions. We examine two specific experimental conditions which are accessible to large laser facilities and are suitable to solve some interesting questions of the stellar community: are the solar internal radiative inte...

  10. LWIR polarimetry for enhanced facial recognition in thermal imagery

    Science.gov (United States)

    Gurton, Kristan P.; Yuffa, Alex J.; Videen, Gorden

    2014-05-01

    We present a series of long-wave-infrared (LWIR) polarimetric-based thermal images of facial profiles in which polarization-state information of the image forming radiance is retained and displayed. The resultant polarimetric images show enhanced facial features, additional texture, and details that are not present in the corresponding conventional thermal imagery. It has been generally thought that conventional thermal imagery (MidiR or LWIR) could not produce the detailed spatial information required for reliable human identification due to the so-called "ghosting" effect often seen in thermal imagery of human subjects. By using polarimetric information, we are able to extract subtle surface features of the human face, thus improving subject identification. The considered polarimetric image sets include the conventional thermal intensity image, S0 , the two Stokes images, S1 and S2, and a Stokes image product called the degree-of-linear-polarization (DoLP) image. Finally, Stokes imagery is combined with Fresnel relations to extract additional 3D surface information.

  11. Physical and radiative properties of the first core accretion shock

    CERN Document Server

    Commerçon, Benoît; Chabrier, Gilles; Chièze, Jean-Pierre

    2011-01-01

    Radiative shocks play a dominant role in star formation. The accretion shocks on the first and second Larson's cores involve radiative processes and are thus characteristic of radiative shocks. In this study, we explore the formation of the first Larson's core and characterize the radiative and dynamical properties of the accretion shock, using both analytical and numerical approaches. We develop both numerical RHD calculations and a semi-analytical model that characterize radiative shocks in various physical conditions, for radiating or barotropic fluids. Then, we perform 1D spherical collapse calculations of the first Larson's core, using a grey approximation for the opacity of the material. We consider three different models for radiative transfer, namely: the barotropic approximation, the FLD approximation and the more complete M1 model. We investigate the characteristic properties of the collapse and of the first core formation. Comparison between the numerical results and our semi-analytical model shows...

  12. Investigating the hohlraum radiation properties through the angular distribution of the radiation temperature

    Science.gov (United States)

    Zhang, H.; Yang, D.; Song, P.; Zou, S.; Zhao, Y.; Li, S.; Li, Z.; Guo, L.; Wang, F.; Zheng, W.; Gu, P.; Pei, W.; Zhu, S.; Jiang, S.; Ding, Y.

    2016-08-01

    The symmetric radiation drive is essential to the capsule implosion in the indirect drive fusion but is hard to achieve due to the non-uniform radiation distribution inside the hohlraum. In this work, the non-uniform radiation properties of both vacuum and gas-filled hohlraums are studied by investigating the angular distribution of the radiation temperature experimentally and numerically. It is found that the non-uniform radiation distribution inside the hohlraum induces the variation of the radiation temperature between different view angles. The simulations show that both the angular distribution of the radiation temperature and the hohlraum radiation distribution can be affected by the electron heat flux. The measured angular distribution of the radiation temperature is more consistent with the simulations when the electron heat flux limiter f e = 0.1 . Comparisons between the experiments and simulations further indicate that the x-ray emission of the blow-off plasma is overestimated in the simulations when it stagnates around the hohlraum axis. The axial position of the laser spot can also be estimated by the angular distribution of the radiation temperature due to their sensitive dependence. The inferred laser spot moves closer to the laser entrance hole in the gas-filled hohlraum than that in the vacuum hohlraum, consisting with the x-ray images taken from the framing camera. The angular distribution of the radiation temperature provides an effective way to investigate the hohlraum radiation properties and introduces more constraint to the numerical modeling of the hohlraum experiments.

  13. 3D-FFT for Signature Detection in LWIR Images

    Energy Technology Data Exchange (ETDEWEB)

    Medvick, Patricia A.; Lind, Michael A.; Mackey, Patrick S.; Nuffer, Lisa L.; Foote, Harlan P.

    2007-11-20

    Improvements in analysis detection exploitation are possible by applying whitened matched filtering within the Fourier domain to hyperspectral data cubes. We describe an implementation of a Three Dimensional Fast Fourier Transform Whitened Matched Filter (3DFFTMF) approach and, using several example sets of Long Wave Infra Red (LWIR) data cubes, compare the results with those from standard Whitened Matched Filter (WMF) techniques. Since the variability in shape of gaseous plumes precludes the use of spatial conformation in the matched filtering, the 3DFFTMF results were similar to those of two other WMF methods. Including a spatial low-pass filter within the Fourier space can improve signal to noise ratios and therefore improve detection limit by facilitating the mitigation of high frequency clutter. The improvement only occurs if the low-pass filter diameter is smaller than the plume diameter.

  14. Radiation processing and functional properties of soybean (Glycine max)

    Energy Technology Data Exchange (ETDEWEB)

    Pednekar, Mrinal, E-mail: mrinal1854@yahoo.co.i [Food Technology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, Maharashtra (India); Das, Amit K. [Department of Food Engineering, CFTRI, Mysore 570020, Karnataka (India); Rajalakshmi, V; Sharma, Arun [Food Technology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, Maharashtra (India)

    2010-04-15

    Effect of radiation processing (10, 20 and 30 kGy) on soybean for better utilization was studied. Radiation processing reduced the cooking time of soybean and increased the oil absorption capacity of soy flour without affecting its proximate composition. Irradiation improved the functional properties like solubility, emulsification activity and foam stability of soybean protein isolate. The value addition effect of radiation processing has been discussed for the products (soy milk, tofu and tofu fortified patties) prepared from soybean.

  15. Radiation processing and functional properties of soybean ( Glycine max)

    Science.gov (United States)

    Pednekar, Mrinal; Das, Amit K.; Rajalakshmi, V.; Sharma, Arun

    2010-04-01

    Effect of radiation processing (10, 20 and 30 kGy) on soybean for better utilization was studied. Radiation processing reduced the cooking time of soybean and increased the oil absorption capacity of soy flour without affecting its proximate composition. Irradiation improved the functional properties like solubility, emulsification activity and foam stability of soybean protein isolate. The value addition effect of radiation processing has been discussed for the products (soy milk, tofu and tofu fortified patties) prepared from soybean.

  16. Deep transfer learning for automatic target classification: MWIR to LWIR

    Science.gov (United States)

    Ding, Zhengming; Nasrabadi, Nasser; Fu, Yun

    2016-05-01

    Publisher's Note: This paper, originally published on 5/12/2016, was replaced with a corrected/revised version on 5/18/2016. If you downloaded the original PDF but are unable to access the revision, please contact SPIE Digital Library Customer Service for assistance. When dealing with sparse or no labeled data in the target domain, transfer learning shows its appealing performance by borrowing the supervised knowledge from external domains. Recently deep structure learning has been exploited in transfer learning due to its attractive power in extracting effective knowledge through multi-layer strategy, so that deep transfer learning is promising to address the cross-domain mismatch. In general, cross-domain disparity can be resulted from the difference between source and target distributions or different modalities, e.g., Midwave IR (MWIR) and Longwave IR (LWIR). In this paper, we propose a Weighted Deep Transfer Learning framework for automatic target classification through a task-driven fashion. Specifically, deep features and classifier parameters are obtained simultaneously for optimal classification performance. In this way, the proposed deep structures can extract more effective features with the guidance of the classifier performance; on the other hand, the classifier performance is further improved since it is optimized on more discriminative features. Furthermore, we build a weighted scheme to couple source and target output by assigning pseudo labels to target data, therefore we can transfer knowledge from source (i.e., MWIR) to target (i.e., LWIR). Experimental results on real databases demonstrate the superiority of the proposed algorithm by comparing with others.

  17. Investigating Radiation Shielding Properties of Different Mineral Origin Heavyweight Concretes

    Science.gov (United States)

    Basyigit, Celalettin; Uysal, Volkan; Kilinçarslan, Şemsettin; Mavi, Betül; Günoǧlu, Kadir; Akkurt, Iskender; Akkaş, Ayşe

    2011-12-01

    The radiation although has hazardous effects for human health, developing technologies bring lots of usage fields to radiation like in medicine and nuclear power station buildings. In this case protecting from undesirable radiation is a necessity for human health. Heavyweight concrete is one of the most important materials used in where radiation should be shielded, like those areas. In this study, used heavyweight aggregates of different mineral origin (Limonite, Siderite), in order to prepare different series in concrete mixtures and investigated radiation shielding properties. The experimental results on measuring the radiation shielding, the heavyweight concrete prepared with heavyweight aggregates of different mineral origin show that, are useful radiation absorbents when they used in concrete mixtures.

  18. Low-Cost, Silicon Carbide Replication Technique for LWIR Mirror Fabrication Project

    Data.gov (United States)

    National Aeronautics and Space Administration — SSG proposes an innovative optical manufacturing approach that will enable the low-cost fabrication of lightweighted, Long Wave Infrared (LWIR) Silicon Carbide (SiC)...

  19. Surface Leakage Suppression in LWIR Type-II Superlattice Photodetectors Using Electrical Gating Technique Project

    Data.gov (United States)

    National Aeronautics and Space Administration — High performance LWIR detectors are highly needed. In order to image from long distance, it is important that imagers have high sensitivity, high resolution, and...

  20. Gimbal Integration to Small Format, Airborne, MWIR and LWIR Imaging Sensors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed innovation is for enhanced sensor performance and high resolution imaging for Long Wave InfraRed (LWIR) and Medium Wave IR (MWIR) camera systems used in...

  1. High Performance Dual Band Photodetector Arrays for MWIR/LWIR Imaging Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposed Phase II program seeks to create dual-band pixel-collocated MWIR/LWIR photodetector arrays based on III-V semiconductor materials in a Type-II...

  2. Thermodynamic properties of the blackbody radiation: A Kaniadakis approach

    Science.gov (United States)

    Lourek, Imene; Tribeche, Mouloud

    2017-02-01

    The thermodynamic properties of the blackbody radiation are revisited, for the first time, within the theoretical framework of the κ-statistics introduced by Kaniadakis. Using the κ-counterpart of the Bose-Einstein distribution, generalized expressions for the free energy, the entropy, the specific heat, and the pressure are obtained. All quantities are shown to recover their standard expressions in the limit κ → 0. The reexamination of the thermodynamic properties of the blackbody radiation shows that it emits more energy with an increase of the value of | κ | in comparison with the standard Planck radiation law. Moreover, the effects of the deformed Kaniadakis statistics are shown to be more appreciable for high temperatures. Our results could be used as a theoretical support for experimental studies implying blackbody radiation such as the study of microwave background radiation.

  3. Comparison of the inversion periods for MidIR and LWIR polarimetric and conventional thermal imagery

    Science.gov (United States)

    Felton, M.; Gurton, K. P.; Pezzaniti, J. L.; Chenault, D. B.; Roth, L. E.

    2010-04-01

    We report the results of a diurnal study in which radiometrically calibrated polarimetric and conventional thermal imagery are recorded in the MidIR and LWIR to identify and compare the respective time periods in which minimum target contrast is achieved. The MidIR polarimetric sensor is based on a division-of-aperture approach and has a 640x512 InSb focal-plane array, while the LWIR polarimetric sensor uses a spinning achromatic retarder to perform the polarimetric filtering and has a 324x256 microbolometer focal-plane array. The images used in this study include the S0 and S1 Stokes images of a scene containing a military vehicle and the natural background. In addition, relevant meteorological parameters measured during the test period include air temperature, ambient loading in the LWIR, relative humidity, cloud cover, height, and density. The data shows that the chief factors affecting polarimetric contrast in both wavebands are the amount of thermal emission from the objects in the scene and the abundance of MidIR and LWIR sources in the optical background. In particular, it has been observed that the MidIR polarimetric contrast was positively correlated to the presence of MidIR sources in the optical background, while the LWIR polarimetric contrast was negatively correlated to the presence of LWIR sources in the optical background.

  4. Numerical Tests and Properties of Waves in Radiating Fluids

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, B M; Klein, R I

    2009-09-03

    We discuss the properties of an analytical solution for waves in radiating fluids, with a view towards its implementation as a quantitative test of radiation hydrodynamics codes. A homogeneous radiating fluid in local thermodynamic equilibrium is periodically driven at the boundary of a one-dimensional domain, and the solution describes the propagation of the waves thus excited. Two modes are excited for a given driving frequency, generally referred to as a radiative acoustic wave and a radiative diffusion wave. While the analytical solution is well known, several features are highlighted here that require care during its numerical implementation. We compare the solution in a wide range of parameter space to a numerical integration with a Lagrangian radiation hydrodynamics code. Our most significant observation is that flux-limited diffusion does not preserve causality for waves on a homogeneous background.

  5. Radiation Shielding Properties of Some Marbles in Turkey

    Science.gov (United States)

    Günoǧlu, K.; Akkurt, I.

    2011-12-01

    Especially after development of technology, radiation started to be used in a large fields such as medicine, industry and energy. Using radiation in those fields bring hazordous effect of radition into humancell. Thus radiation protection becomes important in physics. Although there are three ways for radiation protection, shielding of the radiation is the most commonly used method. Natural Stones such as marble is used as construction material especially in critical building and thus its radiation shielding capability should be determined. In this study, gamma ray shielding properties of some different types of marble mined in Turkey, have been measured using a NaI(Tl) scintillator detector. The measured results were also compared with the theoretical calculations XCOM.

  6. Modeling silica aerogel optical performance by determining its radiative properties

    Directory of Open Access Journals (Sweden)

    Lin Zhao

    2016-02-01

    Full Text Available Silica aerogel has been known as a promising candidate for high performance transparent insulation material (TIM. Optical transparency is a crucial metric for silica aerogels in many solar related applications. Both scattering and absorption can reduce the amount of light transmitted through an aerogel slab. Due to multiple scattering, the transmittance deviates from the Beer-Lambert law (exponential attenuation. To better understand its optical performance, we decoupled and quantified the extinction contributions of absorption and scattering separately by identifying two sets of radiative properties. The radiative properties are deduced from the measured total transmittance and reflectance spectra (from 250 nm to 2500 nm of synthesized aerogel samples by solving the inverse problem of the 1-D Radiative Transfer Equation (RTE. The obtained radiative properties are found to be independent of the sample geometry and can be considered intrinsic material properties, which originate from the aerogel’s microstructure. This finding allows for these properties to be directly compared between different samples. We also demonstrate that by using the obtained radiative properties, we can model the photon transport in aerogels of arbitrary shapes, where an analytical solution is difficult to obtain.

  7. THE IMPACT OF RELATIVE HUMIDITY ON THE RADIATIVE PROPERTY AND RADIATIVE FORCING OF SULFATE AEROSOL

    Institute of Scientific and Technical Information of China (English)

    张立盛; 石广玉

    2001-01-01

    With the data of complex refractive index of sulfate aerosol, the radiative properties of the aerosol under 8 relative humidity conditions are calculated in this paper. By using the concentration distribution from two CTM models and LASG GOALS/AGCM, the radiative forcing due to hygroscopic sulfate aerosol is simulated. The results show that: (1) With the increase of relative humidity, the mass extinction coefficiency factor decreases in the shortwave spectrum: single scattering albedo keeps unchanged except for a little increase in longwave spectrum, and asymmetry factor increases in whole spectrum. (2) Larger differences occur in radiative forcing simulated by using two CTM data, and the global mean forcing is -0. 268 and -0. 816 W/m2,respectively. (3) When the impact of relative humidity on radiative property is taken into account,the distribution pattern of radiative forcing due to the wet particles is very similar to that of dry sulfate, but the forcing value decreases by 6%.

  8. Spectral Radiative Properties of Two-Dimensional Rough Surfaces

    Science.gov (United States)

    Xuan, Yimin; Han, Yuge; Zhou, Yue

    2012-12-01

    Spectral radiative properties of two-dimensional rough surfaces are important for both academic research and practical applications. Besides material properties, surface structures have impact on the spectral radiative properties of rough surfaces. Based on the finite difference time domain algorithm, this paper studies the spectral energy propagation process on a two-dimensional rough surface and analyzes the effect of different factors such as the surface structure, angle, and polarization state of the incident wave on the spectral radiative properties of the two-dimensional rough surface. To quantitatively investigate the spatial distribution of energy reflected from the rough surface, the concept of the bidirectional reflectance distribution function is introduced. Correlation analysis between the reflectance and different impact factors is conducted to evaluate the influence degree. Comparison between the theoretical and experimental data is given to elucidate the accuracy of the computational code. This study is beneficial to optimizing the surface structures of optoelectronic devices such as solar cells.

  9. Properties of the Third Harmonic of the SASE FEL Radiation

    CERN Document Server

    Saldin, E L; Schneidmiller, E

    2005-01-01

    Recent theoretical and experimental studies have shown that SASE FEL with a planar undulator holds a potential for generation of relatively strong coherent radiation at the third harmonic of the fundamental frequency. Here we present detailed study of the nonlinear harmonic generation in SASE FEL obtained with time-dependent FEL simulation code FAST. Using similarity techniques we present universal dependencies for temporal, spectral, and statistical properties of the third harmonic radiation from SASE FEL.

  10. Imaging polarimetry in the LWIR with microgrid polarimeters

    Directory of Open Access Journals (Sweden)

    Tyo J.S.

    2010-06-01

    Full Text Available Microgrid polarimeters have emerged over the past decade as a viable tool for performing real-time, highly accurate polarimetric imagery. A microgrid polarimeter operates by integrating a focal plane array (FPA with an array of micropolarizing optics. Mircrogrids have the advantage of being relatively compact, rugged, and inherently spatiotemporally aligned. However, they have the single disadvantage that the various polarization measurements that go into estimating the Stokes parameters at a particular pixel are actually coming from separate locations in the field. Hence, a microgrid polarimeter performs best where there is no image information, obviating the need for an imaging polarimeter! Recently we have been working with a LWIR microgrid polarimeter at the College of Optical Sciences. Our instrument is a DRS Sensors & Targeting Systems 640 x 480 HgCdTe FPA with linear polarizers at 0°, 45°, 90°, and 135° [1]. In this paper we will review our recent results that derive methods for artifact-free reconstruction of band limited imagery.

  11. Modified algorithm for mineral identification in LWIR hyperspectral imagery

    Science.gov (United States)

    Yousefi, Bardia; Sojasi, Saeed; Liaigre, Kévin; Ibarra Castanedo, Clemente; Beaudoin, Georges; Huot, François; Maldague, Xavier P. V.; Chamberland, Martin

    2017-05-01

    The applications of hyperspectral infrared imagery in the different fields of research are significant and growing. It is mainly used in remote sensing for target detection, vegetation detection, urban area categorization, astronomy and geological applications. The geological applications of this technology mainly consist in mineral identification using in airborne or satellite imagery. We address a quantitative and qualitative assessment of mineral identification in the laboratory conditions. We strive to identify nine different mineral grains (Biotite, Diopside, Epidote, Goethite, Kyanite, Scheelite, Smithsonite, Tourmaline, Quartz). A hyperspectral camera in the Long Wave Infrared (LWIR, 7.7-11.8 ) with a LW-macro lens providing a spatial resolution of 100 μm, an infragold plate, and a heating source are the instruments used in the experiment. The proposed algorithm clusters all the pixel-spectra in different categories. Then the best representatives of each cluster are chosen and compared with the ASTER spectral library of JPL/NASA through spectral comparison techniques, such as Spectral angle mapper (SAM) and Normalized Cross Correlation (NCC). The results of the algorithm indicate significant computational efficiency (more than 20 times faster) as compared to previous algorithms and have shown a promising performance for mineral identification.

  12. Polylogarithmic representation of radiative and thermodynamic properties of thermal radiation in a given spectral range: I. Blackbody radiation

    CERN Document Server

    Fisenko, Anatoliy I

    2014-01-01

    Using polylogarithm functions the exact analytical expressions for the radiative and thermodynamic properties of blackbody radiation, such as the Wien displacement law, Stefan-Boltzmann law, total energy density, number density of photons, Helmholtz free energy density, internal energy density, enthalpy density, entropy density, heat capacity at constant volume, and pressure in the finite range of frequencies are constructed. The obtained expressions allow us to tabulate these functions in various finite frequency bands at different temperatures for practical applications. As an example, the radiative and thermodynamic functions using experimental data for the monopole spectrum of the Cosmic Microwave Background (CMB) radiation measured by the COBE FIRAS instrument in the 60 - 600 GHz frequency interval at the temperature T = 2.725 K are calculated. The expressions obtained for the radiative and thermodynamic functions can be easily presented in wavelength and wavenumber domains.

  13. On the radiative and thermodynamic properties of the cosmic radiations using COBE FIRAS instrument data: I. Cosmic microwave background radiation

    Science.gov (United States)

    Fisenko, Anatoliy I.; Lemberg, Vladimir

    2014-07-01

    Using the explicit form of the functions to describe the monopole and dipole spectra of the Cosmic Microwave Background (CMB) radiation, the exact expressions for the temperature dependences of the radiative and thermodynamic functions, such as the total radiation power per unit area, total energy density, number density of photons, Helmholtz free energy density, entropy density, heat capacity at constant volume, and pressure in the finite range of frequencies v 1≤ v≤ v 2 are obtained. Since the dependence of temperature upon the redshift z is known, the obtained expressions can be simply presented in z representation. Utilizing experimental data for the monopole and dipole spectra measured by the COBE FIRAS instrument in the 60-600 GHz frequency interval at the temperature T=2.72548 K, the values of the radiative and thermodynamic functions, as well as the radiation density constant a and the Stefan-Boltzmann constant σ are calculated. In the case of the dipole spectrum, the constants a and σ, and the radiative and thermodynamic properties of the CMB radiation are obtained using the mean amplitude T amp=3.358 mK. It is shown that the Doppler shift leads to a renormalization of the radiation density constant a, the Stefan-Boltzmann constant σ, and the corresponding constants for the thermodynamic functions. The expressions for new astrophysical parameters, such as the entropy density/Boltzmann constant, and number density of CMB photons are obtained. The radiative and thermodynamic properties of the Cosmic Microwave Background radiation for the monopole and dipole spectra at redshift z≈1089 are calculated.

  14. FlexyDos3D: a deformable anthropomorphic 3D radiation dosimeter: radiation properties

    DEFF Research Database (Denmark)

    De Deene, Yves; Skyt, Peter Sandegaard; Hill, Robin

    2015-01-01

    Three dimensional radiation dosimetry has received growing interest with the implementation of highly conformal radiotherapy treatments. The radiotherapy community faces new challenges with the commissioning of image guided and image gated radiotherapy treatments (IGRT) and deformable image...... and oxygen concentration has also been investigated. The radiophysical properties of this new dosimeter are discussed including stability, spatial integrity, temperature dependence of the dosimeter during radiation, readout and storage, dose rate dependence and tissue equivalence....

  15. Theory and measurement of emittance properties for radiation thermometry applications.

    Science.gov (United States)

    Dewitt, D. P.; Hernicz, R. S.

    1972-01-01

    Some basic concepts of radiation physics are briefly reviewed to provide an introduction to the radiative properties - including emittance, reflectance, absorptance, and transmittance - their definitions, interrelations, theory and methods of measurement. Analyzed data showing typical characteristics of temperature and wavelength dependence, surface effects and environmental influences on the radiation properties of selected classes of materials are presented. Emphasis is placed on those emittance properties of particular interest to conventional radiation thermometry applications, but sufficient generality on all properties is presented to be useful for new or unusual techniques where a more detailed understanding of the behavior of materials is desirable. Data sources are identified to assist the reader in locating property information. It is the intention of the paper to give the reader a background to become more fully aware of the pitfalls, limitations, but of course, advantages in the use of data from the literature. The paper is written in the form of an abbreviated review fully documenting the more important topics and concepts which can only be treated briefly.

  16. Studying laser radiation effect on steel structure and properties

    Directory of Open Access Journals (Sweden)

    А. М. Gazaliyev

    2016-07-01

    Full Text Available There was studied the effect of laser radiation on the structure and properties of annealed and tempered steel with different content of carbon. For surface hardening there was used a laser complex equipped with Nd: YAG pulse laser with power density up to 30 kW/сm2. As a result of the carried-out studies there were calculated characteristics of laser, steel microstructure and properties.

  17. Polylogarithmic representation of radiative and thermodynamic properties of thermal radiation in a given spectral range: II. Real-body radiation

    CERN Document Server

    Fisenko, Anatoliy I

    2015-01-01

    The general analytical expressions for the thermal radiative and thermodynamic properties of a real-body are obtained in a finite range of frequencies at different temperatures. The frequency dependence of the spectral emissivity is represented as a power series. The Stefan-Boltzmann law, total energy density, number density of photons, Helmholtz free energy density, internal energy density, enthalpy density, entropy density, heat capacity at constant volume, pressure, and total emissivity are expressed in terms of the polylogarithm functions. The general expressions for the thermal radiative and thermodynamic functions are applied for the study of thermal radiation of liquid and solid zirconium carbide. These functions are calculated using experimental data for the frequency dependence of the normal spectral emissivity in the visible-near infrared range at the melting (freezing) point. The gaps between the thermal radiative and thermodynamic functions of liquid and solid zirconium carbide are observed. The g...

  18. Fast methods of computing bulk radiative properties of inhomogeneous clouds illuminated by solar radiation

    Energy Technology Data Exchange (ETDEWEB)

    Gabriel, P. [Colorado State Univ., Fort Collins, CO (United States)

    1995-09-01

    The use of cloud fraction as a means of incorporating horizontal cloud inhomogeneity in radiative transfer calculations is widespread in the atmospheric science community. This research attempts to bypass the use of cloud fraction in radiative transfer modeling for two-dimensional media. Gabriel describes two approximation techniques useful in calculating the domain averaged bulk radiative properties such as albedo, flux divergence and mean radiance that dispense with the need to use cloud fraction as a specifier of cloud inhomogeneity. The results suggest that the variability of the medium can largely be accounted for through the pseudo-source term, offering hope of parameterizing the equation of transfer in terms of the statistical properties of the medium. 1 fig.

  19. Development of a Random Field Model for Gas Plume Detection in Multiple LWIR Images.

    Energy Technology Data Exchange (ETDEWEB)

    Heasler, Patrick G.

    2008-09-30

    This report develops a random field model that describes gas plumes in LWIR remote sensing images. The random field model serves as a prior distribution that can be combined with LWIR data to produce a posterior that determines the probability that a gas plume exists in the scene and also maps the most probable location of any plume. The random field model is intended to work with a single pixel regression estimator--a regression model that estimates gas concentration on an individual pixel basis.

  20. Radiation Damage Study on the Electrical Properties of Si Diodes

    Science.gov (United States)

    Pascoalino, Kelly C. S.; Gonçalves, Josemary A. C.; Tobias, Carmen C. B.

    2011-08-01

    The aim of this work was to study the radiation damage effects on the electrical properties of Float Zone (FZ) and Magnetic Czochralski (MCz) diodes. The effects were evaluated by measuring the reverse current and capacitance of these devices as a function of the reverse voltage. The irradiation was performed in the Radiation Technology Center (CTR) at IPEN-CNEN/SP using a 60Co irradiator (Gammacell 220-Nordion) with a dose rate of about 2 kGy/h. Samples were irradiated at room temperature in five steps up to an accumulated dose of 603 kGy.

  1. Solid state temperature-dependent NUC (non-uniformity correction) in uncooled LWIR (long-wave infrared) imaging system

    Science.gov (United States)

    Cao, Yanpeng; Tisse, Christel-Loic

    2013-06-01

    In uncooled LWIR microbolometer imaging systems, temperature fluctuations of FPA (Focal Plane Array) as well as lens and mechanical components placed along the optical path result in thermal drift and spatial non-uniformity. These non-idealities generate undesirable FPN (Fixed-Pattern-Noise) that is difficult to remove using traditional, individual shutterless and TEC-less (Thermo-Electric Cooling) techniques. In this paper we introduce a novel single-image based processing approach that marries the benefits of both statistical scene-based and calibration-based NUC algorithms, without relying neither on extra temperature reference nor accurate motion estimation, to compensate the resulting temperature-dependent non-uniformities. Our method includes two subsequent image processing steps. Firstly, an empirical behavioral model is derived by calibrations to characterize the spatio-temporal response of the microbolometric FPA to environmental and scene temperature fluctuations. Secondly, we experimentally establish that the FPN component caused by the optics creates a spatio-temporally continuous, low frequency, low-magnitude variation of the image intensity. We propose to make use of this property and learn a prior on the spatial distribution of natural image gradients to infer the correction function for the entire image. The performance and robustness of the proposed temperature-adaptive NUC method are demonstrated by showing results obtained from a 640×512 pixels uncooled LWIR microbolometer imaging system operating over a broad range of temperature and with rapid environmental temperature changes (i.e. from -5°C to 65°C within 10 minutes).

  2. Radiation properties of the SASE3 afterburner for European XFEL

    Science.gov (United States)

    Wei, Tao; Li, Peng; Li, Yuhui; Pflueger, Joachim

    2017-05-01

    At present the SASE3 undulator beamline of the European XFEL includes 21 planar undulators which generate horizontally polarized radiation in the soft X-ray region between 0.4 and 5.0nm. In order to satisfy the demand to full polarization control it is planned to install four helical undulator segments at the end of the planar SASE3 undulator system. The helical undulator segments will be used as an afterburner, i.e. they will use the micro-bunched electron beam and produce enhanced coherent radiation at a power level comparable to the linear system but with full polarization control. In this contribution the properties of the emitted radiation will be investigated.

  3. 3D Gray Radiative Properties of a Radiation Hydrodynamic Model of a YSO Accretion Shock

    Science.gov (United States)

    Ibgui, L.; de Sá, L.; Stehlé, C.; Chièze, J.-P.; Orlando, S.; Hubeny, I.; Lanz, T.; Matsakos, T.; González, M.; Bonito, R.

    2014-09-01

    We present preliminary results of radiative properties of a 1D gray radiation hydrodynamic (RHD) model of an accretion shock on a young stellar object (YSO). This model takes into account the transition between the collisional equilibrium regime (local thermodynamic equilibrium, LTE), and the coronal equilibrium regime. Based on the 1D planar structure, we built a 3D cylindrical one. Most notably, the post-shock region obtained in our case is far less extended (by a factor of 10 000) than the typical one obtained with models that assume gray optically thin radiative losses. Moreover, we find that the column is optically thin in its longitudinal dimension, and in the transverse dimension, except over an extremely narrow region (≲ 700 m). Consequently, still under the gray assumption, the photons emitted by the hot slab can propagate through the column and escape freely in all directions, including towards the chromosphere. The radiation flux has therefore components that are perpendicular to the accretion column, which demonstrates that a multidimensional (2D or 3D) radiative model is necessary for such a cylindrical structure. This study needs to be taken forward and expanded, by improving the radiative treatment of the RHD model, through relaxation of both the gray and the LTE approximations for the calculation of opacities, in order to clarify the structure of the post-shock region, which is a major source of emission probed by observations.

  4. Properties of radiation-synthesized polyvinylpyrrolidone/chitosan hydrogel blends

    Science.gov (United States)

    Mahmud, Maznah; Daik, Rusli; Adam, Zainah

    2015-09-01

    Poly(vinylpyrrolidone) (PVP)-crosslinked chitosan hydrogels were prepared by gamma radiation at various doses; 1, 3 5, 7, 10, 15, 20, 25 and 30kGy. Gamma radiation was used as a crosslinking tool which requires no chemical initiator, no heating process and need no purification step on the end products obtained. The hydrogel formulations were composed of 6% chitosan with average molecular weight (Mw) = 48 800 g/mol and 14% PVP with Mw = 10 000 g/mol in 2% lactic acid. Physical properties of hydrogels such as gel fraction and swelling property at pH 5.5 and pH 7.0 as well as syneresis activity were determined. It was found that different radiation dose induces different effect on hydrogels' network formed. Morphological study of hydrogels has been carried out by scanning electron microscope (SEM). From these preliminary evaluations, it can be concluded that gamma radiation is an effective tool for network development of hydrogels and it also induces enhancement on characteristics of hydrogels synthesized.

  5. Properties of radiation-synthesized polyvinylpyrrolidone/chitosan hydrogel blends

    Energy Technology Data Exchange (ETDEWEB)

    Mahmud, Maznah [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia 43600 Bangi, Selangor (Malaysia); Radiation Processing Technology Division, Malaysian Nuclear Agency, 43000 Kajang, Selangor (Malaysia); Daik, Rusli [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia 43600 Bangi, Selangor (Malaysia); Adam, Zainah [Radiation Processing Technology Division, Malaysian Nuclear Agency, 43000 Kajang, Selangor (Malaysia)

    2015-09-25

    Poly(vinylpyrrolidone) (PVP)-crosslinked chitosan hydrogels were prepared by gamma radiation at various doses; 1, 3 5, 7, 10, 15, 20, 25 and 30kGy. Gamma radiation was used as a crosslinking tool which requires no chemical initiator, no heating process and need no purification step on the end products obtained. The hydrogel formulations were composed of 6% chitosan with average molecular weight (Mw) = 48 800 g/mol and 14% PVP with Mw = 10 000 g/mol in 2% lactic acid. Physical properties of hydrogels such as gel fraction and swelling property at pH 5.5 and pH 7.0 as well as syneresis activity were determined. It was found that different radiation dose induces different effect on hydrogels’ network formed. Morphological study of hydrogels has been carried out by scanning electron microscope (SEM). From these preliminary evaluations, it can be concluded that gamma radiation is an effective tool for network development of hydrogels and it also induces enhancement on characteristics of hydrogels synthesized.

  6. Phase errors and their effect on undulator radiation properties

    Directory of Open Access Journals (Sweden)

    Richard P. Walker

    2013-01-01

    Full Text Available A detailed analysis is carried out of the various types of phase errors present in real undulator devices, and their statistical properties. The influence of phase errors on the radiation properties is also examined, distinguishing the effects on peak brightness and integrated flux, and including the effects of electron beam emittance and energy spread. The limitation of the usual expression for the reduction in intensity due to phase errors, based on the rms phase error, is explored, and a new parameter is introduced which correlates better with the reduction in integrated flux. The implications for operation of undulators in future lower emittance storage rings is also discussed.

  7. LWIR hyperspectral change detection for target acquisition and situation awareness in urban areas

    NARCIS (Netherlands)

    Dekker, R.J.; Schwering, P.B.W.; Benoist, K.W.; Pignatti, S.; Santini, F.; Friman, O.

    2013-01-01

    This paper studies change detection of LWIR (Long Wave Infrared) hyperspectral imagery. Goal is to improve target acquisition and situation awareness in urban areas with respect to conventional techniques. Hyperspectral and conventional broadband high-spatial-resolution data were collected during th

  8. Toxic properties of specific radiation determinant molecules, derived from radiated species

    Science.gov (United States)

    Popov, Dmitri; Maliev, Vecheslav; Kedar, Prasad; Casey, Rachael; Jones, Jeffrey

    Introduction: High doses of radiation induce the formation of radiation toxins in the organs of irradiated mammals. After whole body irradiation, cellular macromolecules and cell walls are damaged as a result of long-lived radiation-induced free radicals, reactive oxygen species, and fast, charged particles of radiation. High doses of radiation induce breaks in the chemical bonds of macromolecules and cross-linking reactions via chemically active processes. These processes result in the creation of novel modified macromolecules that possess specific toxic and antigenic properties defined by the type and dose of irradiation by which they are generated. Radiation toxins isolated from the lymph of irradiated animals are classified as hematotoxic, neurotoxic, and enteric non-bacterial (GI) radiation toxins, and they play an important role in the development of hematopoietic, cerebrovascular, and gastrointestinal acute radiation syndromes (ARS). Seven distinct toxins derived from post-irradiated animals have been designated as Specific Radiation Determinants (SRD): SRD-1 (neurotoxic radiation toxin generated by the cerebrovascular form of ARS), SRD-3 (enteric non-bacterial radiation toxins generated by the gastrointestinal form of ARS), and SRD-4 (hematotoxic radiation toxins generated by the hematological, bone marrow form of ARS). SRD-4 is further subdivided into four groups depending on the severity of the ARS induced: SRD-4/1, mild ARS; SRD-4/2, moderate ARS; SRD-4/3, severe ARS; and SRD-4/4, extremely severe ARS. The seventh SRD, SRD-2 is a toxic extract derived from animals suffering from a fourth form of ARS, as described in European literature and produces toxicity primarily in the autonimic nervous system. These radiation toxins have been shown to be responsible for the induction of important pathophysiological, immunological, and biochemical reactions in ARS. Materials and Methods: These studies incorporated the use of statistically significant numbers of a

  9. Radiation toxins: molecular mechanisms of action and radiomimetic properties .

    Science.gov (United States)

    Popov, Dmitri; Maliev, Vecheslav

    . Injection of SRD-3 in toxic doses to experimen-tal animals. The clinical symptoms were: increased peristalsis, vomiting, diarrhea with blood. Postmortem section demonstrated multiple petechiae on the cell walls and serous membranes of the abdomen. Experiment N4. Injection of SRD-4 to experimental animals resulted in develop-ment lymphocytopenia, leukocytopenia, trombocytopenia. Autopsy of those animals that died showed changes that are specific a Hematopoietic form of the ARS with development of marked hemorrhagias into tissues of internal organs. Conclusion: 1. Administration of radiation toxins of SRD group to radiation naive animals in toxic doses 0.1 mg/kg; 0,5 mg/kg; 1 mg/kg; 2 mg/kg;3 mg/kg up to 30 mg/kg and more initiates development of specific toxic reactions with symptoms of the ARS. 2.Biological molecules of the Radiation Toxins SRD-group possess both toxic and antigenic properties.

  10. Polylogarithmic Representation of Radiative and Thermodynamic Properties of Thermal Radiation in a Given Spectral Range: II. Real-Body Radiation

    Science.gov (United States)

    Fisenko, Anatoliy I.; Lemberg, Vladimir

    2015-11-01

    There are several classes of materials and space objects for which the frequency dependence of the spectral emissivity is represented as a power series. Therefore, the study of the properties of thermal radiation for these real bodies is an important task for both fundamental science and industrial applications. The general analytical expressions for the thermal radiative and thermodynamic functions of a real body are obtained in a finite range of frequencies at different temperatures. The Stefan-Boltzmann law, total energy density, number density of photons, Helmholtz free energy density, internal energy density, enthalpy density, entropy density, heat capacity at constant volume, pressure, and total emissivity are expressed in terms of the polylogarithm functions. The obtained general expressions for the thermal radiative and thermodynamic functions are applied for the study of thermal radiation of liquid and solid zirconium carbide. These functions are calculated using experimental data for the frequency dependence of the normal spectral emissivity in the visible and near-infrared range at the melting (freezing) point. The gaps between the thermal radiative and thermodynamic functions of liquid and solid zirconium carbide are observed. The general analytical expressions obtained can easily be presented in the wavenumber domain.

  11. EFFECTS OF GAMMA RADIATION ON ELECTROCHEMICAL PROPERTIES OF IONIC LIQUIDS

    Energy Technology Data Exchange (ETDEWEB)

    Visser, A; Nicholas Bridges, N; Thad Adams, T; John Mickalonis, J; Mark02 Williamson, M

    2009-04-21

    The electrochemical properties of ionic liquids (ILs) make them attractive for possible replacement of inorganic salts in high temperature molten salt electrochemical processing of nuclear fuel. To be a feasible replacement solvent, ILs need to be stable in moderate and high doses of radiation without adverse chemical and physical effects. Here, we exposed seven different ILs to a 1.2 MGy dose of gamma radiation to investigate their physical and chemical properties as they related to radiological stability. The azolium-based ILs experienced the greatest change in appearance, but these ILs were chemically more stable to gamma radiation than some of the other classes of ILs tested, due to the presence of aromatic electrons in the azolium ring. All the ILs exhibited a decrease in their conductivity and electrochemical window (at least 1.1 V), both of which could affect the utility of ILs in electrochemical processing. The concentration of the irradiation decomposition products was less than 3 mole %, with no impurities detectable using NMR techniques.

  12. Radiation properties of slot and dipole elements on layered substrates

    Science.gov (United States)

    Rogers, R. L.; Neikirk, D. P.

    1989-06-01

    Calculation results are presented for the radiation properties of slot and dipole antennas on electrically thick grounded dielectric substrates, with application to the development of mm-wave and far-IR imaging arrays. Factors considered in the selection of dieletric layers include the beam patterns, surface waves losses, and the type of element used. The effects of dielectric and ground plane losses are taken into account for the case of high-gain structures. Results for the efficiencies and beam patterns of three and five layer structures show that, in combination with a twin element configuration, both slot and dipole antennas can overcome the problem of losses to surface waves in the substrate and be made to efficiently radiate to air on these layered dielectric structures.

  13. Structure and Infrared Radiation Properties of Substituted Cordierites

    Institute of Scientific and Technical Information of China (English)

    XU Qing; SONG Chaowen; CHEN Wen; LIU Xiaofang; ZHANG Feng

    2006-01-01

    Zn2+ - or Ti4+ -substituted cordierites with the nominal compositions of Mg1.6 Zn0.4 Al4 Si5 O18 and Mg1.8 Ti0.2 Al4.4 Si4.6 O18 respectively, were prepared by a conventional solid state reaction method. The structure of the substituted cordierites was characterized by X- ray diffraction (XRD), infrared ( IR ) spectroscopy and 29 Si magic angle spinning ( MAS ) nuclear magnetic resonance ( NMR ). The infrared radiation properties were investigated in the bands within 2.5-25 μm. Compared with the un-substituted cordierite composition ( Mg2 Al4 Si5 O18 ), Zn2+ - or Ti4+ -substituted cordierites show superior infrared properties . XRD and IR results confirm the formation of hexagonal α-cordierite as the main crystal phase for the substituted cordierites. 29 Si MAS NMR result indicates that Zn2+ or Ti4+ substitutions for partial Mg2+ of a- cordierite promoted the ordering of the distribution of Al and Si atoms in T1 ( tetrahedra connecting six-membered rings together with [ MgO6 ] octahedra ) and T2 ( tetraheda forming six- membered rings ) tetrahedral sites. This resulted in a lattice deformation and increased the anharmonicity of polarization vibration, which is responsible for the improvement of infrared radiation properties of the substituted cordierites.

  14. Equilibrium properties of blackbody radiation in Doubly Special Relativity

    CERN Document Server

    Chandra, Nitin; Vaibhav, Vinay

    2016-01-01

    Doubly Special Relativity (DSR) is an attempt to incorporate an observer independent energy/length scale in the relativistic theory. We study various thermodynamic properties of blackbody radiation in DSR. We find that the energy density, specific heat etc. follows usual acoustic phonon dynamics as has been well studied by Debye. Other thermodynamic quantities like pressure, entropy etc. has also been calculated. The usual Stefan-Boltzmann law gets modified. The phase-space measure is also expected to get modified for an exotic spacetime, which in turn leads to the modification of Planck energy density distribution and the Wien's displacement law.

  15. Calculation of the radiative properties of photosynthetic microorganisms

    Science.gov (United States)

    Dauchet, Jérémi; Blanco, Stéphane; Cornet, Jean-François; Fournier, Richard

    2015-08-01

    A generic methodological chain for the predictive calculation of the light-scattering and absorption properties of photosynthetic microorganisms within the visible spectrum is presented here. This methodology has been developed in order to provide the radiative properties needed for the analysis of radiative transfer within photobioreactor processes, with a view to enable their optimization for large-scale sustainable production of chemicals for energy and chemistry. It gathers an electromagnetic model of light-particle interaction along with detailed and validated protocols for the determination of input parameters: morphological and structural characteristics of the studied microorganisms as well as their photosynthetic-pigment content. The microorganisms are described as homogeneous equivalent-particles whose shape and size distribution is characterized by image analysis. The imaginary part of their refractive index is obtained thanks to a new and quite extended database of the in vivo absorption spectra of photosynthetic pigments (that is made available to the reader). The real part of the refractive index is then calculated by using the singly subtractive Kramers-Krönig approximation, for which the anchor point is determined with the Bruggeman mixing rule, based on the volume fraction of the microorganism internal-structures and their refractive indices (extracted from a database). Afterwards, the radiative properties are estimated using the Schiff approximation for spheroidal or cylindrical particles, as a first step toward the description of the complexity and diversity of the shapes encountered within the microbial world. Finally, these predictive results are confronted to experimental normal-hemispherical transmittance spectra for validation. This entire procedure is implemented for Rhodospirillum rubrum, Arthrospira platensis and Chlamydomonas reinhardtii, each representative of the main three kinds of photosynthetic microorganisms, i.e. respectively

  16. Radiation induced oxidative degradation of polymers. 3. Effect of radiation on mechanical properties. [Gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Seguchi, T.; Arakawa, K.; Ito, M.; Hayakawa, N.; Machi, S. (Japan Atomic Energy Research Inst., Takasaki, Gunma. Takasaki Radiation Chemistry Research Establishment)

    1983-01-01

    The changes of mechanical properties of various kinds of polyethylene (PE) and ethylene-propylene copolymer (EPR) with the irradiation in air, in oxygen of 10 atm, and under vacuum were investigated. The decrease in the elongation (Esub(b)) and the tensile strength (Tsub(b)) of PE by the irradiation in oxygen is larger than under vacuum. The changes of Esub(b) well reflect the degradation of PE. In case of EPR, the Tsub(b) decreases sharply with dose in any environments, and the Esub(b) decreases under vacuum to a larger extent than in oxygen. The modulus at 200% elongation of EPR increases with dose under vacuum, but decreases in oxygen. When the samples were irradiated in air, the changes of the mechanical properties were the intermediate between oxygen and vacuum and dependent on the ratio of oxidation and non-oxidation layers in the film. The antioxidant (Irganox 1010 or DPPD) mixed in polymers was found to retard effectively the polymer degradation by the irradiation in oxygen.

  17. Radiative and combustion properties of nanoparticle-laden liquids

    Science.gov (United States)

    Tyagi, Himanshu

    Key processes in energy conversion systems are radiative transport and combustion. The general objective of this dissertation is to improve energy conversion efficiency by a fundamental investigation of how nanoparticle-laden liquid suspensions, generally termed nanofluids, can be used to either enhance radiative absorption in solar thermal energy systems, or to improve the combustion properties of liquid fuels. The present study theoretically investigates the feasibility of using a non-concentrating direct absorption solar collector (DAC) and compares its performance with that of a typical flat-plate collector. Here a nanofluid - a mixture of water and aluminum nanoparticles - is used as the absorbing medium. It was observed that the presence of nanoparticles increases the absorption of incident radiation by more than 9 times over that of pure water. Under similar operating conditions, the efficiency of a DAC using nanofluid as the working fluid is found to be up to 10 percent higher (on an absolute basis) than that of a flat-plate collector. This study also attempts to improve the ignition properties of diesel fuel by investigating the influence of adding aluminum and aluminum-oxide nanoparticles to diesel. As part of this study, droplet ignition experiments were carried out atop a heated hot plate over the range of 688 to 768 degrees centigrade. Different types of fuel mixtures were used; both particle size (15 nm and 50 nm) as well as the volume fraction (0, 0.1 and 0.5 percent) of nanoparticles added to diesel were varied. It was observed that the ignition probability for the fuel mixtures which contained nanoparticles was significantly higher than that of pure diesel. Finally, the concept of using solar energy for converting biomass into useful product-gases was explored. A molten salt mixture (containing nanoparticles) was used to absorb and transfer solar energy to the biomass. Under the highest amount of solar radiation (60 times the normal solar radiation

  18. Radiation damage in silicon. Defect analysis and detector properties

    Energy Technology Data Exchange (ETDEWEB)

    Hoenniger, F.

    2008-01-15

    acceptor, a model has been introduced to describe the radiation induced changes in macrsocopic detector properties as affected by the microscopic defect generation. Finally charge collection measurements have been performed at high radiation doses. (orig.)

  19. A compact LWIR Fourier transform imaging spectrometer employing a variable gap Fabry-Perot interferometer

    Science.gov (United States)

    Zhang, Fang; Gao, Jiaobo; Liu, Fang; Zhao, Yujie; Zheng, Yawei; Zhang, Lei

    2016-10-01

    With unique working principle and spectral characteristic, the long wave infrared (LWIR) interferometric spectral imaging is a popular technology with wide application in many fields. In order to miniaturize and light the instrument, a new method of LWIR spectral imaging system based on a variable gap Fabry-Perot (FP) interferometer is researched. With the system working principle analyzed, theoretically, it is researched that how to make certain the primary parameter, such as, the reflectivity of the two interferometric cavity surfaces and the wedge angle of interferometric cavity. A prototype is developed and good experimental results of blackbody and polypropylene film are obtained. The research shows that besides high throughput and high spectral resolution, the advantage of miniaturization is also simultaneously achieved in this method.

  20. Variation in MidIR and LWIR polarimetric imagery due to diurnal and meteorological impacts

    Science.gov (United States)

    Gurton, Kristan P.; Felton, Melvin

    2008-04-01

    We present radiometric and polarimetric calibrated imagery recorded in both the mid-wave IR (MidIR) and long wave IR (LWIR) as a function diurnal variation over several multiday periods. We compare differences in polarimetric and conventional thermal imagry for both IR atmospheric transmission windows, i.e., 3-5μm and 8-12 μm regions. Meteorological parameters measured during the study include temperature, relative-humidity, wind-speed/direction, precipitation, and ambient atmospheric IR loading. The two camera systems used in the study differed significantly in design. The LWIR polarimetric sensor utilizes a spinning achromatic retarder and is best suited for static scenes, while the MidIR system is based on a division-of-aperture design and is capable of recording polarimetric imagery of targets that are rapidly moving. Examples of both S0 (conventional thermal) and degree-of-linear polarization (DOLP) imagery are presented and compared.

  1. The full spectral radiative properties of Proxima Centauri

    Science.gov (United States)

    Ribas, Ignasi; Gregg, Michael D.; Boyajian, Tabetha S.; Bolmont, Emeline

    2017-07-01

    Context. The discovery of Proxima b, a terrestrial temperate planet, presents the opportunity of studying a potentially habitable world in optimal conditions. A key aspect in the modeling of its habitability is to understand the radiation environment of the planet in the full spectral domain. Aims: We aim to characterize the X-rays to mid-IR radiative properties of Proxima with the goal of providing the top-of-atmosphere fluxes on the planet. We also aim at constraining the fundamental properties of the star, namely its mass, radius, effective temperature and luminosity. Methods: We have employed observations from a large number of facilities and made use of different methodologies to piece together the full spectral energy distribution of Proxima. In the high-energy domain, we payed particular attention to the contributions of rotational modulation, activity cycle, and flares so that the data provided are representative of the overall radiation dose received by the atmosphere of the planet. Results: We present the full spectrum of Proxima covering 0.7 to 30 000 nm. The integration of the data shows that the top-of-atmosphere average XUV irradiance on Proxima b is 0.293 W m-2, that is, nearly 60 times higher than Earth, and that the total irradiance is 877 ± 44 W m-2, or 64 ± 3% of the solar constant but with a significantly redder spectrum. We also provide laws for the XUV evolution of Proxima corresponding to two scenarios, one with a constant XUV-to-bolometric luminosity value throughout its history and another one in which Proxima left the saturation phase at an age of about 1.6 Gyr and is now in a power-law regime. Regarding the fundamental properties of Proxima, we find M = 0.120 ± 0.003 M⊙, R = 0.146 ± 0.007 R⊙, Teff = 2980 ± 80 K, and L = 0.00151 ± 0.00008 L⊙. In addition, our analysis reveals a 20% excess in the 3-30 μm flux of the star that is best interpreted as arising from warm dust in the system. Conclusions: The data provided here should

  2. Light scattering reviews 7 radiative transfer and optical properties of atmosphere and underlying surface

    CERN Document Server

    Kokhanovsky, Alexander A

    2014-01-01

    This book describes modern advances in radiative transfer and light scattering. Coverage includes fast radiative transfer techniques, use of polarization in remote sensing and recent developments in remote sensing of snow properties from space observations.

  3. Properties of an ultrarelativistic charged particle radiation in a constant homogeneous crossed electromagnetic field

    CERN Document Server

    Bogdanov, O V; Lazarenko, G Yu

    2016-01-01

    The properties of radiation created by a classical ultrarelativistic scalar charged particle in a constant homogeneous crossed electromagnetic field are described both analytically and numerically with radiation reaction taken into account in the form of the Landau-Lifshitz equation. The total radiation naturally falls into two parts: the radiation formed at the entrance point of a particle into the crossed field (the synchrotron entrance radiation), and the radiation coming from the late-time asymptotics of a particle motion (the de-excited radiation). The synchrotron entrance radiation resembles, although does not coincide with, the ultrarelativistic limit of the synchrotron radiation: its distribution over energies and angles possesses almost the same properties. The de-excited radiation is soft, not concentrated in the plane of motion of a charged particle, and almost completely circularly polarized. The photon energy delivering the maximum to its spectral angular distribution decreases with increasing th...

  4. Moving beyond flat earth: dense 3D scene reconstruction from a single FL-LWIR camera

    Science.gov (United States)

    Stone, K.; Keller, J. M.; Anderson, D. T.

    2013-06-01

    In previous work an automatic detection system for locating buried explosive hazards in forward-looking longwave infrared (FL-LWIR) and forward-looking ground penetrating radar (FL-GPR) data was presented. This system consists of an ensemble of trainable size-contrast filters prescreener coupled with a secondary classification step which extracts cell-structured image space features, such as local binary patterns (LBP), histogram of oriented gradients (HOG), and edge histogram descriptors (EHD), from multiple looks and classifies the resulting feature vectors using a support vector machine. Previously, this system performed image space to UTM coordinate mapping under a flat earth assumption. This limited its applicability to flat terrain and short standoff distances. This paper demonstrates a technique for dense 3D scene reconstruction from a single vehicle mounted FL-LWIR camera. This technique utilizes multiple views and standard stereo vision algorithms such as polar rectification and optimal correction. Results for the detection algorithm using this 3D scene reconstruction approach on data from recent collections at an arid US Army test site are presented. These results are compared to those obtained under the flat earth assumption, with special focus on rougher terrain and longer standoff distance than in previous experiments. The most recent collection also allowed comparison between uncooled and cooled FL-LWIR cameras for buried explosive hazard detection.

  5. Aerosol properties and associated radiative effects over Cairo (Egypt)

    Science.gov (United States)

    El-Metwally, M.; Alfaro, S. C.; Wahab, M. M. Abdel; Favez, O.; Mohamed, Z.; Chatenet, B.

    2011-02-01

    Cairo is one of the largest megacities in the World and the particle load of its atmosphere is known to be particularly important. In this work we aim at assessing the temporal variability of the aerosol's characteristics and the magnitude of its impacts on the transfer of solar radiation. For this we use the level 2 quality assured products obtained by inversion of the instantaneous AERONET sunphotometer measurements performed in Cairo during the Cairo Aerosol CHaracterization Experiment (CACHE), which lasted from the end of October 2004 to the end of March 2006. The analysis of the temporal variation of the aerosol's optical depth (AOD) and spectral dependence suggests that the aerosol is generally a mixture of at least 3 main components differing in composition and size. This is confirmed by the detailed analysis of the monthly-averaged size distributions and associated optical properties (single scattering albedo and asymmetry parameter). The components of the aerosol are found to be 1) a highly absorbing background aerosol produced by daily activities (traffic, industry), 2) an additional, 'pollution' component produced by the burning of agricultural wastes in the Nile delta, and 3) a coarse desert dust component. In July, an enhancement of the accumulation mode is observed due to the atmospheric stability favoring its building up and possibly to secondary aerosols being produced by active photochemistry. More generally, the time variability of the aerosol's characteristics is due to the combined effects of meteorological factors and seasonal production processes. Because of the large values of the AOD achieved during the desert dust and biomass burning episodes, the instantaneous aerosol radiative forcing (RF) at both the top (TOA) and bottom (BOA) of the atmosphere is maximal during these events. For instance, during the desert dust storm of April 8, 2005 RF BOA, RF TOA, and the corresponding atmospheric heating rate peaked at - 161.7 W/m 2, - 65.8 W/m 2

  6. Potential of the Thermal Infrared Wavelength Region to predict semi-arid Soil Surface Properties for Remote Sensing Monitoring

    Science.gov (United States)

    Eisele, Andreas; Chabrillat, Sabine; Lau, Ian; Hecker, Christoph; Hewson, Robert; Carter, Dan; Wheaton, Buddy; Ong, Cindy; Cudahy, Thomas John; Kaufmann, Hermann

    2014-05-01

    Digital soil mapping with the means of passive remote sensing basically relies on the soils' spectral characteristics and an appropriate atmospheric window, where electromagnetic radiation transmits without significant attenuation. Traditionally the atmospheric window in the solar-reflective wavelength region (visible, VIS: 0.4 - 0.7 μm; near infrared, NIR: 0.7 - 1.1 μm; shortwave infrared, SWIR: 1.1 - 2.5 μm) has been used to quantify soil surface properties. However, spectral characteristics of semi-arid soils, typically have a coarse quartz rich texture and iron coatings that can limit the prediction of soil surface properties. In this study we investigated the potential of the atmospheric window in the thermal wavelength region (long wave infrared, LWIR: 8 - 14 μm) to predict soil surface properties such as the grain size distribution (texture) and the organic carbon content (SOC) for coarse-textured soils from the Australian wheat belt region. This region suffers soil loss due to wind erosion processes and large scale monitoring techniques, such as remote sensing, is urgently required to observe the dynamic changes of such soil properties. The coarse textured sandy soils of the investigated area require methods, which can measure the special spectral response of the quartz dominated mineralogy with iron oxide enriched grain coatings. By comparison, the spectroscopy using the solar-reflective region has limitations to discriminate such arid soil mineralogy and associated coatings. Such monitoring is important for observing potential desertification trends associated with coarsening of topsoil texture and reduction in SOC. In this laboratory study we identified the relevant LWIR wavelengths to predict these soil surface properties. The results showed the ability of multivariate analyses methods (PLSR) to predict these soil properties from the soil's spectral signature, where the texture parameters (clay and sand content) could be predicted well in the models

  7. Radiation properties and emissivity parameterization of high level thin clouds

    Science.gov (United States)

    Wu, M.-L. C.

    1984-01-01

    To parameterize emissivity of clouds at 11 microns, a study has been made in an effort to understand the radiation field of thin clouds. The contributions to the intensity and flux from different sources and through different physical processes are calculated by using the method of successive orders of scattering. The effective emissivity of thin clouds is decomposed into the effective absorption emissivity, effective scattering emissivity, and effective reflection emissivity. The effective absorption emissivity depends on the absorption and emission of the cloud; it is parameterized in terms of optical thickness. The effective scattering emissivity depends on the scattering properties of the cloud; it is parameterized in terms of optical thickness and single scattering albedo. The effective reflection emissivity follows the similarity relation as in the near infrared cases. This is parameterized in terms of the similarity parameter and optical thickness, as well as the temperature difference between the cloud and ground.

  8. Exploring gamma radiation effect on exoelectron emission properties of bone

    Energy Technology Data Exchange (ETDEWEB)

    Zakaria, M.; Dekhtyar, Y.; Bogucharska, T.; Noskov, V. [Riga Technical Univ., Biomedical Engineering and Nanotechnology Institute (Latvia)

    2006-07-01

    Gamma radiation is used for radiation therapy to treat carcinogenic diseases including bone cancer. Ionising radiation kills carcinogenic calls. However, there are side effects of the gamma radiation on the bone surface electron structure. One of the effects is in the form of altering electron density of states of bone that, with time, influences biomedical reactions on bone life condition. (authors)

  9. The Atmospheric Radiation Measurement Program May 2003 Intensive Operations Period Examining Aerosol Properties and Radiative Influences: Preface to Special Section

    Science.gov (United States)

    Ferrare, Richard; Feingold, Graham; Ghan, Steven; Ogren, John; Schmid, Beat; Schwartz, Stephen E.; Sheridan, Pat

    2006-01-01

    Atmospheric aerosols influence climate by scattering and absorbing radiation in clear air (direct effects) and by serving as cloud condensation nuclei, modifying the microphysical properties of clouds, influencing radiation and precipitation development (indirect effects). Much of present uncertainty in forcing of climate change is due to uncertainty in the relations between aerosol microphysical and optical properties and their radiative influences (direct effects) and between microphysical properties and their ability to serve as cloud condensation nuclei at given supersaturations (indirect effects). This paper introduces a special section that reports on a field campaign conducted at the Department of Energy Atmospheric Radiation Measurement site in North Central Oklahoma in May, 2003, examining these relations using in situ airborne measurements and surface-, airborne-, and space-based remote sensing.

  10. GLYCOLIC ACID PHYSICAL PROPERTIES, IMPURITIES, AND RADIATION EFFECTS ASSESSMENT

    Energy Technology Data Exchange (ETDEWEB)

    Lambert, D.; Pickenheim, B.; Hay, M.

    2011-06-20

    The Defense Waste Processing Facility (DWPF) is pursuing alternative reductants/flowsheets to increase attainment to meet closure commitment dates. In fiscal year 2009, SRNL evaluated several options and recommended the further assessment of the nitric/formic/glycolic acid flowsheet. SRNL is currently performing testing with this flowsheet to support the DWPF down-select of alternate reductants. As part of the evaluation, SRNL was requested to determine the physical properties of formic and glycolic acid blends. Blends of formic acid in glycolic acid were prepared and their physical properties tested. Increasing amounts of glycolic acid led to increases in blend density, viscosity and surface tension as compared to the 90 wt% formic acid that is currently used at DWPF. These increases are small, however, and are not expected to present any difficulties in terms of processing. The effect of sulfur impurities in technical grade glycolic acid was studied for its impact on DWPF glass quality. While the glycolic acid specification allows for more sulfate than the current formic acid specification, the ultimate impact is expected to be on the order of 0.03 wt% sulfur in glass. Note that lower sulfur content glycolic acid could likely be procured at some increased cost if deemed necessary. A paper study on the effects of radiation on glycolic acid was performed. The analysis indicates that substitution of glycolic acid for formic acid would not increase the radiolytic production rate of H{sub 2} and cause an adverse effect in the SRAT or SME process. It has been cited that glycolic acid solutions that are depleted of O{sub 2} when subjected to large radiation doses produced considerable quantities of a non-diffusive polymeric material. Considering a constant air purge is maintained in the SRAT and the solution is continuously mixed, oxygen depletion seems unlikely, however, if this polymer is formed in the SRAT solution, the rheology of the solution may be affected and

  11. The Effect of Radiations on the Structural and Electrical Properties of Device Technologies: Comparison and Trends

    OpenAIRE

    Jain, C.P.

    2014-01-01

    The effects of radiation on the structural and electrical properties of electronic devices are complex in nature and have changed much during decades of device evolution. These effects are mainly because of radiation induced charge build-up in oxide and interfacial regions. This paper presents a details of these radiation induced effects, their dependencies, and the change in structural properties and electrical characterises of different devices before and after irradiation are measured and ...

  12. QCL as a game changer in MWIR and LWIR military and homeland security applications

    Science.gov (United States)

    Patel, C. Kumar N.; Lyakh, Arkadiy; Maulini, Richard; Tsekoun, Alexei; Tadjikov, Boris

    2012-06-01

    QCLs represent an important advance in MWIR and LWIR laser technology. With the demonstration of CW/RT QCLs, large number applications for QCLs have opened up, some of which represent replacement of currently used laser sources such as OPOs and OPSELs, and others being new uses which were not possible using earlier MWIR/LWIR laser sources, namely OPOs, OPSELs and CO2 lasers. Pranalytica has made significant advances in CW/RT power and WPE of QCLs and through its invention of a new QCL structure design, the non-resonant extraction, has demonstrated single emitter power of >4.7 W and WPE of >17% in the 4.4μm-5.0μm region. Pranalytica has also been commercially supplying the highest power MWIR QCLs with high WPEs. The NRE design concept now has been extended to the shorter wavelengths (3.8μm-4.2μm) with multiwatt power outputs and to longer wavelengths (7μm-10μm) with >1 W output powers. The high WPE of the QCLs permits RT operation of QCLs without using TECs in quasi-CW mode where multiwatt average powers are obtained even in ambient T>70°C. The QCW uncooled operation is particularly attractive for handheld, battery-operated applications where electrical power is limited. This paper describes the advances in QCL technology and applications of the high power MWIR and LWIR QCLs for defense applications, including protection of aircraft from MANPADS, standoff detection of IEDs, insitu detection of CWAs and explosives, infrared IFF beacons and target designators. We see that the SWaP advantages of QCLs are game changers.

  13. On the radiative and thermodynamic properties of the extragalactic far infrared background radiation using COBE FIRAS instrument data

    CERN Document Server

    Fisenko, Anatoliy I

    2014-01-01

    Using the explicit form of the function to describe the average spectrum of the extragalactic far infrared background (FIRB) radiation measured by the COBE FIRAS instrument in the 0.15 - 2.4 THz frequency interval, the radiative and thermodynamic properties, such as the total emissivity, total radiation power per unit area, total energy density, number density of photons, Helmholtz free energy density, entropy density, heat capacity at constant volume, pressure, enthalpy density, and internal energy density are calculated. The calculated value of the total intensity received in the 0.15 - 2.4 THz frequency interval is 13.6 nW m^-2 sr^-1, and comprises about 19.4 % of the total intensity expected from the energy released by stellar nucleosynthesis over cosmic history. The radiative and thermodynamic functions of the extragalactic far infrared background (FIRB) radiation are calculated at redshift z = 1.5.

  14. Radiative properties of advanced spacecraft heat shield materials

    Science.gov (United States)

    Cunnington, G. R.; Funai, A. I.; Mcnab, T. K.

    1983-01-01

    Experimental results are presented to show the effects of simulated reentry exposure by convective heating and by radiant heating on spectral and total emittance of statically oxidized Inconel 617 and Haynes HS188 superalloys to 1260 K and a silicide coatea (R512E) columbium 752 alloy to 1590 K. Convective heating exposures were conducted in a supersonic arc plasma wind tunnel using a wedge-shaped specimen configuration. Radiant tests were conducted at a pressure of .003 atmospheres of dry air at a flow velocity of several meters per second. Convective heating specimens were subjected to 8, 20, and 38 15-min heating cycles, and radiant heating specimens were tested for 10, 20, 50, and 100 30-min heating cycles. Changes in radiative properties are explained in terms of changes in composition resulting from simulated reentry tests. The methods used to evaluate morphological, compositional and crystallographic changes include: Auger electron spectroscopy; scanning electron microscopy; X-ray diffraction analysis; and electron microprobe analysis.

  15. SWIR, VIS and LWIR observer performance against handheld objects: a comparison

    Science.gov (United States)

    Adomeit, Uwe

    2016-10-01

    The short wave infrared spectral range caused interest to be used in day and night time military and security applications in the last years. This necessitates performance assessment of SWIR imaging equipment in comparison to the one operating in the visual (VIS) and thermal infrared (LWIR) spectral range. In the military context (nominal) range is the main performance criteria. Discriminating friend from foe is one of the main tasks in today's asymmetric scenarios and so personnel, human activities and handheld objects are used as targets to estimate ranges. The later was also used for an experiment at Fraunhofer IOSB to get a first impression how the SWIR performs compared to VIS and LWIR. A human consecutively carrying one of nine different civil or military objects was recorded from five different ranges in the three spectral ranges. For the visual spectral range a 3-chip color-camera was used, the SWIR range was covered by an InGaAs-camera and the LWIR by an uncooled bolometer. It was ascertained that the nominal spatial resolution of the three cameras was in the same magnitude in order to enable an unbiased assessment. Daytime conditions were selected for data acquisition to separate the observer performance from illumination conditions and to some extend also camera performance. From the recorded data, a perception experiment was prepared. It was conducted as a nine-alternative forced choice, unlimited observation time test with 15 observers participating. Before the experiment, the observers were trained on close range target data. Outcome of the experiment was the average probability of identification versus range between camera and target. The comparison of the range performance achieved in the three spectral bands gave a mixed result. On one hand a ranking VIS / SWIR / LWIR in decreasing order can be seen in the data, but on the other hand only the difference between VIS and the other bands is statistically significant. Additionally it was not possible

  16. Properties of an ultrarelativistic charged particle radiation in a constant homogeneous crossed electromagnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Bogdanov, O.V., E-mail: bov@tpu.ru [Physics Faculty, Tomsk State University, Tomsk, 634050 (Russian Federation); Department of Higher Mathematics and Mathematical Physics, Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation); Kazinski, P.O., E-mail: kpo@phys.tsu.ru [Physics Faculty, Tomsk State University, Tomsk, 634050 (Russian Federation); Department of Higher Mathematics and Mathematical Physics, Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation); Lazarenko, G.Yu., E-mail: lazarenko.georgijj@icloud.com [Physics Faculty, Tomsk State University, Tomsk, 634050 (Russian Federation)

    2017-05-15

    The properties of radiation created by a classical ultrarelativistic scalar charged particle in a constant homogeneous crossed electromagnetic field are described both analytically and numerically with radiation reaction taken into account in the form of the Landau–Lifshitz equation. The total radiation naturally falls into two parts: the radiation formed at the entrance point of a particle into the crossed field (the synchrotron entrance radiation), and the radiation coming from the late-time asymptotics of a particle motion (the de-excited radiation). The synchrotron entrance radiation resembles, although does not coincide with, the ultrarelativistic limit of the synchrotron radiation: its distribution over energies and angles possesses almost the same properties. The de-excited radiation is soft, not concentrated in the plane of motion of a charged particle, and almost completely circularly polarized. The photon energy delivering the maximum to its spectral angular distribution decreases with increasing the initial energy of a charged particle, while the maximum value of this distribution remains the same at the fixed photon observation angle and entrance angle of a charged particle. The ultraviolet and infrared asymptotics of the total radiation are also described. - Highlights: • Properties of an electron radiation in a crossed electromagnetic field are studied. • Spectral angular distribution of the synchrotron entrance radiation is described. • Spectral angular distribution of the de-excited radiation is described. • De-excited radiation is almost completely circularly polarized. • Photon energy at the maximum of the de-excited radiation decreases with increasing the initial energy of an electron.

  17. HgZnTe-based detectors for LWIR NASA applications

    Science.gov (United States)

    Patten, Elizabeth A.; Kalisher, Murray H.

    1990-01-01

    The initial goal was to grow and characterize HgZnTe and determine if it indeed had the advantageous properties that were predicted. Researchers grew both bulk and liquid phase epitaxial HgZnTe. It was determined that HgZnTe had the following properties: (1) microhardness at least 50 percent greater than HgCdTe of equivalent bandgap; (2) Hg annealing rates of at least 2 to 4 times longer than HgCdTe; and (3) higher Hg vacancy formation energies. This early work did not focus on one specific composition (x-value) of HgZnTe since NASA was interested in HgZnTe's potential for a variety of applications. Since the beginning of 1989, researchers have been concentrating, however, on the liquid phase growth of very long wavelength infrared (VLWIR) HgZnTe (cutoff approx. equals 17 microns at 65K) to address the requirements of the Earth Observing System (EOS). Since there are no device models to predict the advantages in reliability one can gain with increased microhardness, surface stability, etc., one must fabricate HgZnTe detectors and assess their relative bake stability (accelerated life test behavior) compared with HgCdTe devices fabricated in the same manner. Researchers chose to fabricate HIT detectors as a development vehicle for this program because high performance in the VLWIR has been demonstrated with HgCdTe HIT detectors and the HgCdTe HIT process should be applicable to HgZnTe. HIT detectors have a significant advantage for satellite applications since these devices dissipate much less power than conventional photoconductors to achieve the same responsivity.

  18. Influence of x-ray radiation on the properties of magnetorheological elastomers

    Science.gov (United States)

    Yu, M.; Fu, J.; Ju, B. X.; Zheng, X.; Choi, S. B.

    2013-12-01

    In this work, the influence of x-ray radiation on the properties of magnetorheological elastomers (MREs) was experimentally investigated. Five MRE samples with the same composition were prepared, and then were irradiated by an x-ray detection machine, with different radiation doses. The microstructures of samples before and after x-ray irradiation were observed by using scanning electron microscopy. The dynamic mechanical properties of all samples were investigated under different magnetic flux densities. The experimental results indicated that the x-rays had a great impact on the properties of MRE. Due to the x-ray radiation, two kinds of radiation-induced effects were generated in the MRE, which were radiation-induced crosslinking and radiation-induced degradation. Based on the influence of the radiation-induced effects on MRE, the initial modulus of the MRE was increased by the radiation-induced crosslinking effect, but the MR effect of the MRE decreased. While the MRE began to degrade, the MR effect of the MRE exhibited a large increasing trend with the increase of the x-ray radiation dose. In addition, the damping property of the MRE was also influenced greatly by the x-ray radiation, and the loss factor of the MRE was increased dramatically first and then decreased under x-ray irradiation. On the basis of these results, this study may provide a good guideline for developing various applications of MREs.

  19. Spectral properties of Compton inverse radiation: Application of Compton beams

    CERN Document Server

    Bulyak, Eugene

    2013-01-01

    Compton inverse radiation emitted due to backscattering of laser pulses off the relativistic electrons possesses high spectral density and high energy of photons - in hard x-ray up to gamma-ray energies - because of short wavelength of laser radiation as compared with the classical electromagnetic devices such as undulators. In this report, the possibility of such radiation to monochromatization by means of collimation is studied. Two approaches have been considered for the description of the spectral-angular density of Compton radiation based on the classical field theory and on the quantum electrodynamics. As is shown, both descriptions produce similar total spectra. On the contrary, angular distribution of the radiation is different: the classical approach predicted a more narrow radiation cone. Also proposed and estimated is a method of the `electronic' monochromatization based on the electronic subtraction of the two images produced by the electron beams with slightly different energies. A `proof-of-prin...

  20. Full-band structure modeling of the radiative and non-radiative properties of semiconductor materials and devices (Presentation Recording)

    Science.gov (United States)

    Bellotti, Enrico; Wen, Hanqing; Pinkie, Benjamin; Matsubara, Masahiko; Bertazzi, Francesco

    2015-08-01

    Understanding the radiative and non-radiative properties of semiconductor materials is a prerequisite for optimizing the performance of existing light emitters and detectors and for developing new device architectures based on novel materials. Due to the ever increasing complexity of novel semiconductor systems and their relative technological immaturity, it is essential to have design tools and simulation strategies that include the details of the microscopic physics and their dependence on the macroscopic (continuum) variables in the macroscopic device models. Towards this end, we have developed a robust full-band structure based approach that can be used to study the intrinsic material radiative and non-radiative properties and evaluate the same characteristics of low-dimensional device structures. A parallel effort is being carried out to model the effect of substrate driven stress/strain and material quality (dislocations and defects) on microscopic quantities such as non-radiative recombination rate. Using this modeling approach, we have extensively studied the radiative and non-radiative properties of both elemental (Si and Ge) and compound semiconductors (HgCdTe, InGaAs, InAsSb and InGaN). In this work we outline the details of the modelling approach, specifically the challenges and advantages related to the use of the full-band description of the material electronic structure. We will present a detailed comparison of the radiative and Auger recombination rates as a function of temperature and doping for HgCdTe and InAsSb that are two important materials for infrared detectors and emitters. Furthermore we will discuss the role of non-radiatiave Auger recombination processes in explaining the performance of light emitter diodes. Finally we will present the extension of the model to low dimensional structures employed in a number of light emitter and detector structures.

  1. Novel concept of TDI readout circuit for LWIR detector

    Science.gov (United States)

    Kim, Byunghyuck; Yoon, Nanyoung; Lee, Hee Chul; Kim, Choong-Ki

    2000-07-01

    Noise property is the prime consideration in readout circuit design. The output noise caused by the photon noise, which dominates total noise in BLIP detectors, is limited by the integration time that an element looks at a specific point in the scene. Large integration time leads to a low noise performance. Time-delay integration (TDI) is used to effectively increase the integration time and reduce the photon noise. However, it increases the number of dead pixels and requires large integration capacitors and low noise output stage of the readout circuit. In this paper, to solve these problems, we propose a new concept of readout circuit, which performs background suppression, cell-to-cell background current non-uniformity compensation, and dead pixel correction using memory, ADC, DAC, and current copier cell. In simulation results, comparing with the conventional TDI readout circuit, the integration capacitor size can be reduced to 1/5 and trans-impedance gain can be increased by five times. Therefore, the new TDI readout circuit does not require large area and low noise output stage. And the error of skimming current is less than 2%, and the fixed pattern noise induced by cell-to-cell background current variation is reduced to less than 1%.

  2. Laboratory-Measured Rainfall Effects on LWIR Soil Reflectance

    Science.gov (United States)

    Howington, S. E.; Ballard, J., Jr.; Wilhelms, S.

    2012-12-01

    The long-wave infrared reflectance of soils will often have distinct spectral characteristics that depend on the soil's physical and spectral properties. Rainfall has the effect of sorting soil particles at the ground surface, thus changing its long-wave infrared reflectance. This study examines how rainfall alters the measured directional-hemispherical thermal infrared (8-14 μm) spectral reflectance by comparing disturbed soil with undisturbed soil and pre-rain with post-rain conditions. The study uses a soil with a specified sand/silt ratio and a calibrated, laboratory rainfall simulator. For an accumulated rainfall of 8 cm, the mean disturbed soil thermal infrared spectral reflectance within 8.1 - 9.2 μm waveband increases from an initial reflectance of 13 percent to a maximum reflectance of 31 percent. Sixty percent of this reflectance change occurred with only 1 cm accumulated rainfall. This study shows that, for this described disturbed sand/silt soil mixture, small accumulated rainfall amounts significantly alter the directional-hemispherical thermal infrared spectral reflectance.

  3. On the radiative and thermodynamic properties of the cosmic radiations using COBE FIRAS instrument data: II. Extragalactic far infrared background radiation

    Science.gov (United States)

    Fisenko, Anatoliy I.; Lemberg, Vladimir

    2014-07-01

    Using formula to describe the average spectrum of the extragalactic far infrared background (FIRB) radiation measured by the COBE FIRAS instrument in the 0.15-2.4 THz frequency interval at mean temperature T=18.5 K, the radiative and thermodynamic properties, such as the total emissivity, total radiation power per unit area, total energy density, number density of photons, Helmholtz free energy density, entropy density, heat capacity at constant volume, and pressure are calculated. The value for the total intensity received in the 0.15-2.4 THz frequency interval is equal to 13.6 nW m-2 sr-1. This value is about 19.4 % of the total intensity expected from the energy released by stellar nucleosynthesis over cosmic history. The radiative and thermodynamic functions of the extragalactic far infrared background (FIRB) radiation are calculated at redshift z=1.5.

  4. Optical characterization of OLED emitter properties by radiation pattern analyses

    Energy Technology Data Exchange (ETDEWEB)

    Flaemmich, Michael

    2011-09-08

    Researches in both, academia and industry are investigating optical loss channels in OLED layered systems by means of optical simulation tools in order to derive promising concepts for a further enhancement of the overall device performance. Besides other factors, the prospects of success of such optimization strategies rely severely on the credibility of the optical input data. The present thesis provides a guideline to measure the active optical properties of OLED emitter materials in situ by radiation pattern analyses. Reliable and widely applicable methods are introduced to determine the internal electroluminescence spectrum, the profile of the emission zone, the dipole emitter orientation, and the internal luminescence quantum efficiency of emissive materials from the optical far field emission of OLEDs in electrical operation. The proposed characterization procedures are applied to sets of OLEDs containing both, fluorescent polymeric materials as well as phosphorescent small-molecular emitters, respectively. On the one hand, quite expected results are obtained. On the other hand, several novel and truly surprising results are found. Most importantly, this thesis contains the first report of a non-isotropic, mainly parallel emitter orientation in a phosphorescent small-molecular guest-host system (Ir(MDQ)2(acac) in a-NPD). Due to the latter result, emitter orientation based optimization of phosphorescent OLEDs seems to be within reach. Since parallel dipoles emit preferably into air, the utilization of smart emissive materials with advantageous molecular orientation is capable to boost the efficiency of phosphorescent OLEDs by 50%. Materials design, the influence of the matrix material and the substrate, as well as film deposition conditions are just a few parameters that need to be studied further in order to exploit the huge potential of the dipole emitter orientation in phosphorescent OLEDs.

  5. Photodetector development at Fraunhofer IAF: From LWIR to SWIR operating from cryogenic close to room temperature

    Science.gov (United States)

    Daumer, V.; Gramich, V.; Müller, R.; Schmidt, J.; Rutz, F.; Stadelmann, T.; Wörl, A.; Rehm, R.

    2017-02-01

    Photodetectors in the non-visible region of the electromagnetic spectrum are essential for security, defense and space science as well as industrial and scientific applications. The research activities at Fraunhofer IAF cover a broad range in the infrared (IR) regime. Whereas short-wavelength IR (SWIR, <1.7 μm) detectors are realized by InGaAs/InP structures, InAs/GaSb type-II superlattice (T2SL) infrared detectors are developed for the spectral bands from mid- (MWIR, 3-5 μm) to long-wavelength IR (LWIR, 8-12 μm). We report on the extension of the superlattice empirical pseudopotential method (SEPM) to 300 K for the design of LWIR heterostructures for operation near room temperature. Recently, we have also adapted heterostructure concepts to our well established bi-spectral T2SL MWIR detector resulting in a dark current density below 2 × 10-9 A/cm2 for a cut-off wavelength close to 5 μm. Finally, we present first results obtained with a gated viewing system based on our InGaAs/InAlAs/InP avalanche photodiode arrays.

  6. Improving the detection task performance of a LWIR imaging system through the use of wavefront coding

    Science.gov (United States)

    Gross, Kevin A.; Kubala, Kenny

    2007-04-01

    In a traditional optical system the imaging performance is maximized at a single point in the operational space. This characteristic leads to maximizing the probability of detection if the object is on axis, at the designed conjugate, with the designed operational temperature and if the system components are manufactured without error in form and alignment. Due to the many factors that influence the system's image quality the probability of detection will decrease away from this peak value. An infrared imaging system is presented that statistically creates a higher probability of detection over the complete operational space for the Hotelling observer. The system is enabled through the use of wavefront coding, a computational imaging technology in which optics, mechanics, detection and signal processing are combined to enable LWIR imaging systems to be realized with detection task performance that is difficult or impossible to obtain in the optical domain alone. The basic principles of statistical decision theory will be presented along with a specific example of how wavefront coding technology can enable improved performance and reduced sensitivity to some of the fundamental constraints inherent in LWIR systems.

  7. Standoff chemical D and Id with extended LWIR hyperspectral imaging spectroradiometer

    Science.gov (United States)

    Prel, Florent; Moreau, Louis; Lavoie, Hugo; Bouffard, François; Thériault, Jean-Marc; Vallieres, Christian; Roy, Claude; Dubé, Denis

    2013-05-01

    Standoff detection and identification (D and Id) of unknown volatile chemicals such as chemical pollutants and consequences of industrial incidents has been increasingly desired for first responders and for environmental monitoring. On site gas detection sensors are commercially available and several of them can even detect more than one chemical species, however only few of them have the capabilities of detecting a wide variety of gases at long and safe distances. The ABB Hyperspectral Imaging Spectroradiometer (MR-i), configured for gas detection detects and identifies a wide variety of chemical species including toxic industrial chemicals (TICs) and surrogates several kilometers away from the sensor. This configuration is called iCATSI for improved Compact Atmospheric Sounding Interferometer. iCATSI is a standoff passive system. The modularity of the MR-i platform allows optimization of the detection configuration with a 256 x 256 Focal Plane Array imager or a line scanning imager both covering the long wave IR atmospheric window up to 14 μm. The uniqueness of its extended LWIR cut off enables to detect more chemicals as well as provide higher probability of detection than usual LWIR sensors.

  8. Influence of radiation damage on BGO scintillation properties

    Energy Technology Data Exchange (ETDEWEB)

    Georgii, R.; Meissl, R.; Lichti, G.G.; Schoenfelder, V. [Max-Planck-Institut fuer Extraterrestrische Physik, Garching (Germany); Hajdas, W. [Paul-Scherrer Institut, CH-5232 Villigen (Switzerland); Henschel, H. [Fraunhofer-Institut fuer Naturwissenschaftlich-Technische Trendanalyse, D-53879 Euskirchen (Germany); Graef, H.-D.; Neumann-Cosel, P. von; Richter, A. [Institut fuer Kernphysik, Technische Universitaet Darmstadt, D-64289 Darmstadt (Germany)

    1998-08-11

    Aboard INTEGRAL, the next medium-size {gamma}-ray mission of the European Space Agency (ESA), a high-resolution Ge-spectrometer array with a BGO anticoincidence shield and imaging capability will be flown. The influence of the radiation damage on the photoelectron yield of the BGO scintillators due to the radiation environment in the orbit, i.e. {gamma}-rays, electrons and protons from the radiation, belts and the cosmic diffuse radiation, was investigated. Irradiation tests with doses equivalent to the orbit conditions were performed and the photoelectron yields of different BGO crystals were measured. It was found that for equal doses the reduction of the photoelectron yield varies strongly for the crystals of different manufacturers. Furthermore, electromagnetic radiation affects the photoelectron yield much stronger than particle radiation. A possible explanation is given by interpreting the effect due to {gamma}-rays primarily as damage of the electronic structure of the BGO, whereas the particle radiation damages mainly the crystal structure. (orig.) 19 refs.

  9. Structural and Radiation Shielding Properties of a Martian Habitat Material Synthesized From In-Situ Resources

    Science.gov (United States)

    Sen, S.; Caranza, S.; Bhattacharya, M.; Makel, D. B.

    2006-01-01

    The 2 primary requirements of a Martian habitat structure include sufficient structural integrity and effective radiation shielding. In addition, the capability to synthesize such building materials primarily from in-situ resources would significantly reduce the cost associated with transportation of such materials and structures from earth. To demonstrate the feasibility of such an approach we have fabricated samples in the laboratory using simulated in-situ resources, evaluated radiation shielding effectiveness using radiation transport codes and radiation test data, and conducted mechanical properties testing. In this paper we will present experimental results that demonstrate the synthesis of polyethylene from a simulated Martian atmosphere and the fabrication of a composite material using simulated Martian regolith with polyethylene as the binding material. Results from radiation transport calculations and data from laboratory radiation testing using a 500 MeV/nucleon Fe beam will be discussed. Mechanical properties of the proposed composite as a function of composition and processing parameters will also be presented.

  10. Design investigation of a cost-effective dual-band (MWIR/LWIR) and a wide band optically athermalized application

    Science.gov (United States)

    Ding, Fujian; Washer, Joe; Morgen, Daniel

    2016-10-01

    Dual-band and wide-band lenses covering both the MWIR and LWIR spectral bands are increasingly needed as dualband MWIR/LWIR detectors have become prevalent and broadband applications have expanded. Currently in dual-band /wide-band applications, the use of more than three elements per lens group and the use of chalcogenide glass is common. This results in expensive systems. Also, many chalcogenides are available only in small diameters, which is a problem for large aperture broadband lenses. In this paper an investigation of cost-effective designs for dual-band MWIR/LWIR lens using only widely available IR materials, specifically Ge, ZnSe and ZnS were performed. An athermalized dual-band MWIR/LWIR using these three materials is presented. The performance analysis of this lens shows that this design form with these three common IR materials works well in certain applications. The required large size blanks of these materials can be easily obtained. Traditional chromatic aberration correction without diffraction for either wide-band or dual-band application was employed. In addition, the methods of harmonic diffraction for dual-band applications, especially with one narrow band, were used for two different presented designs.

  11. Advanced LWIR hyperspectral sensor for on-the-move proximal detection of liquid/solid contaminants on surfaces

    Science.gov (United States)

    Giblin, Jay P.; Dixon, John; Dupuis, Julia R.; Cosofret, Bogdan R.; Marinelli, William J.

    2017-05-01

    Sensor technologies capable of detecting low vapor pressure liquid surface contaminants, as well as solids, in a noncontact fashion while on-the-move continues to be an important need for the U.S. Army. In this paper, we discuss the development of a long-wave infrared (LWIR, 8-10.5 μm) spatial heterodyne spectrometer coupled with an LWIR illuminator and an automated detection algorithm for detection of surface contaminants from a moving vehicle. The system is designed to detect surface contaminants by repetitively collecting LWIR reflectance spectra of the ground. Detection and identification of surface contaminants is based on spectral correlation of the measured LWIR ground reflectance spectra with high fidelity library spectra and the system's cumulative binary detection response from the sampled ground. We present the concepts of the detection algorithm through a discussion of the system signal model. In addition, we present reflectance spectra of surfaces contaminated with a liquid CWA simulant, triethyl phosphate (TEP), and a solid simulant, acetaminophen acquired while the sensor was stationary and on-the-move. Surfaces included CARC painted steel, asphalt, concrete, and sand. The data collected was analyzed to determine the probability of detecting 800 μm diameter contaminant particles at a 0.5 g/m2 areal density with the SHSCAD traversing a surface.

  12. Radiative properties of the urban fabric derived from surface form analysis: A simplified solar balance model

    OpenAIRE

    BERNABE, Anne; Musy, Marjorie; ANDRIEU, Hervé; Calmet, Isabelle

    2015-01-01

    Urban shape determines the absorption and emission of radiation. Urban fabrics are characterized by the solar trapping effect due to multiple reflections of radiation within the geometry, in turn generating increased energy absorption that contributes to the urban heat island. Interactions between urban radiative properties and urban shape are studied through an analytical development. A simplified solar balance model is developed based on morphological indicators. A processing chain is perfo...

  13. Cloud forming properties of ambient aerosol in the Netherlands and resultant shortwave radiative forcing of climate

    NARCIS (Netherlands)

    Khlystov, A.

    1998-01-01

    This thesis discusses properties of ambient aerosols in the Netherlands which are controlling the magnitude of the local aerosol radiative forcing. Anthropogenic aerosols influence climate by changing the radiative transfer through the atmosphere via two effects, one is direct and a second

  14. Aerosol properties and radiative forcing for three air masses transported in Summer 2011 to Sopot, Poland

    Science.gov (United States)

    Rozwadowska, Anna; Stachlewska, Iwona S.; Makuch, P.; Markowicz, K. M.; Petelski, T.; Strzałkowska, A.; Zieliński, T.

    2013-05-01

    Properties of atmospheric aerosols and solar radiation reaching the Earth's surface were measured during Summer 2011 in Sopot, Poland. Three cloudless days, characterized by different directions of incoming air-flows, which are typical transport pathways to Sopot, were used to estimate a radiative forcing due to aerosols present in each air mass.

  15. Cloud forming properties of ambient aerosol in the Netherlands and resultant shortwave radiative forcing of climate.

    NARCIS (Netherlands)

    Khlystov, A.

    1998-01-01

    This thesis discusses properties of ambient aerosols in the Netherlands which are controlling the magnitude of the local aerosol radiative forcing. Anthropogenic aerosols influence climate by changing the radiative transfer through the atmosphere via two effects, one is direct and a second is indire

  16. Radiative properties of materials with surface scattering or volume scattering: A review

    Institute of Scientific and Technical Information of China (English)

    Qunzhi ZHU; Hyunjin LEE; Zhuomin M. ZHANG

    2009-01-01

    Radiative properties of rough surfaces, parti-culate media and porous materials are important in thermal engineering and many other applications. These properties are often needed for calculating heat transfer between surfaces and volume elements in participating media, as well as for accurate radiometric temperature measure-ments. In this paper, recent research on scattering of thermal radiation by rough surfaces, fibrous insulation, soot, aerogel, biological materials, and polytetrafluor-oethylene (PTFE) is reviewed. Both theoretical modeling and experimental investigation are discussed. Rigorous solutions and approximation methods for surface scattering and volume scattering are described. The approach of using measured surface roughness statistics in Monte Carlo simulations to predict radiative properties of rough surfaces is emphasized. The effects of various parameters on the radiative properties of particulate media and porous materials are summarized.

  17. On the radiative and thermodynamic properties of the cosmic radiations using COBE FIRAS instrument data: III. Galactic far-infrared radiation

    Science.gov (United States)

    Fisenko, Anatoliy I.; Lemberg, Vladimir

    2015-07-01

    Using the three-component spectral model describing the FIRAS average continuum spectra, the exact analytical expressions for thermodynamic and radiative functions of Galactic far-infrared radiation are obtained. The COBE FIRAS instrument data in the 0.15-2.88 THz frequency interval at the mean temperatures of T1 = 17.72 K, T2 = 14 K and T3 = 6.73 K are used for calculating the radiative and thermodynamic functions, such as the total radiation power per unit area, total energy density, total emissivity, number density of photons, Helmholtz free energy density, entropy density, heat capacity at constant volume and pressure for the warm, intermediate-temperature and very cold components of the Galactic continuum spectra. The generalized Stefan-Boltzmann law for warm, intermediate-temperature and very cold components is constructed. The temperature dependence of each component is determined by the formula IS-B(T) = σ‧T6. This result is important when we construct the cosmological models of radiative transfer that can be applied inside the Galaxy. Within the framework of the three-component spectral model, the total number of photons in our Galaxy and the total radiation power (total luminosity) emitted from a surface of the Galaxy are calculated. Their values are NGtotal = 1.3780 × 1068 and IGtotal(T) = 1.0482 × 1036 W. Other radiative and thermodynamic properties of the Galactic far-infrared radiation (photon gas) of the Galaxy are calculated. The expressions for astrophysical parameters, such as the entropy density/Boltzmann constant and number density of the Galactic far-infrared photons are obtained. We assume that the obtained analytical expressions for thermodynamic and radiative functions may be useful for describing the continuum spectra of the far-infrared radiation for other galaxies.

  18. Effect of Ionizing Radiation on the Properties of Porous Silicon Nanostructures

    Directory of Open Access Journals (Sweden)

    I.B. Olenych

    2015-12-01

    Full Text Available The influence of ionizing radiation from 226Ra source on the electrical and photoluminescent properties of porous silicon nanostructures was investigated. After the radiation exposure, AC resistance of experimental samples decreased and luminescence band was changed. Temperature dependencies of electrical conductivity and depolarization current were studied in 80-325 K temperature range. Effect of radiation on the energy distribution of localized electronic states in porous silicon based structures is analyzed. Obtained results expand the application prospective of porous silicon for radiation sensing.

  19. Ground-based measurements of aerosol optical properties and radiative forcing in North China

    Institute of Scientific and Technical Information of China (English)

    Hongbin Chen; Xiangao Xia; Pucai Wang; Wenxing Zhang

    2007-01-01

    In order to gain an insight into the aerosol properties and their climatic effect over the continental source regions of China, it is of significance to carry out long-term ground-based measurements of aerosol optical properties and radiative forcing. A couple of temporary and permanent Aerosol Robotic Network (AERONET) sites and three comprehensive radiative sites were established in China as a result of international cooperation in recent years. Heavy aerosol loading and significant temporal and spatial variation over North China are revealed by the AERONET data.Aerosol-induced reductions in surface radiation budget are examined on the basis of collocated observations by sun photometers and pyranometers.

  20. The utilize of gamma radiation on the examination of mechanical properties of polymeric materials

    Directory of Open Access Journals (Sweden)

    F. Greškovič

    2012-04-01

    Full Text Available The article deals about the application area of radiation crosslinking of plastics, which follows after the injection moulding. The main objective of the presented article is the research of influence irradiation dosage on mechanical properties of materials: PP filled by 15 % of mineral filler – talc. Mechanical properties - tensile strength and impact strength by Charpy were examined in dependence on absorbed dose of the gamma rays on various conditions and were compared with non-irradiated samples. Radiation processing involves mainly the use of either electron beams from electron accelerators or gamma radiation from Cobalt-60 sources.

  1. Engineering steps for optimizing high temperature LWIR HgCdTe photodiodes

    Science.gov (United States)

    Madejczyk, Pawel; Gawron, Waldemar; Martyniuk, Piotr; Keblowski, Artur; Pusz, Wioletta; Pawluczyk, Jaroslaw; Kopytko, Malgorzata; Rutkowski, Jaroslaw; Rogalski, Antoni; Piotrowski, Jozef

    2017-03-01

    The authors report on energy gap engineering solutions to improve the high-temperature performance of long-wave infrared (LWIR) HgCdTe photodiodes. Metalorganic chemical vapour deposition (MOCVD) technology with a wide range of composition and donor/acceptor doping and without ex-situ post grown annealing seems to be an excellent tool for HgCdTe heterostructure epitaxial growth. The heterojunction HgCdTe photovoltaic device based on epitaxial graded gap structures integrated with Auger-suppression is a magnificent solution for high operating temperature (HOT) infrared detectors. The thickness, composition and doping of HgCdTe heterostructure were optimized with respect to photoelectrical parameters like dark current, the responsivity and the response time. In this paper we focus on graded interface abruptness in the progressive optimization.

  2. Long range robust multi-terawatt MWIR and LWIR atmospheric light bullets

    Science.gov (United States)

    Moloney, Jerome V.; Schuh, Kolja; Panagiotopoulos, Paris; Kolesik, M.; Koch, S. W.

    2017-05-01

    There is a strong push worldwide to develop multi-Joule femtosecond duration laser pulses at wavelengths around 3.5-4 and 9-11μm within important atmospheric transmission windows. We have shown that pulses with a 4 μm central wavelength are capable of delivering multi-TW powers at km range. This is in stark contrast to pulses at near-IR wavelengths which break up into hundreds of filaments with each carrying around 5 GW of power per filament over meter distances. We will show that nonlinear envelope propagators fail to capture the true physics. Instead a new optical carrier shock singularity emerges that can act to limit peak intensities below the ionization threshold leading to low loss long range propagation. At LWIR wavelengths many-body correlations of weakly-ionized electrons further suppress the Kerr focusing nonlinearity around 10μm and enable whole beam self-trapping without filaments.

  3. Investigation of radiation keeping property of barite coated cloth via image processing method

    Energy Technology Data Exchange (ETDEWEB)

    Kilincarslan, S.; Akkurt, I.; Molla, T.; Akarslan, F. [Department of Construction Education, Suleyman Demirel University, Isparta (Turkey); Department of Physics, Science Faculty, Suleyman Demirel University, Isparta (Turkey); Department of Construction Education, Suleyman Demirel University, Isparta (Turkey); Textil Engineering, Engineering Faculty, Suleyman Demirel University, Isparta (Turkey)

    2012-09-06

    Preservative clothes which are able to absorb radiation beam are needed not only for saving people working at radioactive environment but also for saving others from natural and man-made radiation sources we are exposed in daily life. Barite is a mineral which can be used for armour plating because of high atomic numbered element barium constituent of barite. In this study, armour plating property of barite was applied to fabrics. Barite coated fabric having characteristic of keeping radiation was obtained by penetrating barite on cloth via coating method. Radiation keeping property of fabrics obtained was determined via image processing. The results of experiments showed that barite coated fabrics have blocked radiation more than normal fabrics have done.

  4. On the linear properties of the nonlinear radiative transfer problem

    Science.gov (United States)

    Pikichyan, H. V.

    2016-11-01

    In this report, we further expose the assertions made in nonlinear problem of reflection/transmission of radiation from a scattering/absorbing one-dimensional anisotropic medium of finite geometrical thickness, when both of its boundaries are illuminated by intense monochromatic radiative beams. The new conceptual element of well-defined, so-called, linear images is noteworthy. They admit a probabilistic interpretation. In the framework of nonlinear problem of reflection/transmission of radiation, we derive solution which is similar to linear case. That is, the solution is reduced to the linear combination of linear images. By virtue of the physical meaning, these functions describe the reflectivity and transmittance of the medium for a single photon or their beam of unit intensity, incident on one of the boundaries of the layer. Thereby the medium in real regime is still under the bilateral illumination by external exciting radiation of arbitrary intensity. To determine the linear images, we exploit three well known methods of (i) adding of layers, (ii) its limiting form, described by differential equations of invariant imbedding, and (iii) a transition to the, so-called, functional equations of the "Ambartsumyan's complete invariance".

  5. LWIR passive perception system for stealthy unmanned ground vehicle night operations

    Science.gov (United States)

    Lee, Daren; Rankin, Arturo; Huertas, Andres; Nash, Jeremy; Ahuja, Gaurav; Matthies, Larry

    2016-05-01

    Resupplying forward-deployed units in rugged terrain in the presence of hostile forces creates a high threat to manned air and ground vehicles. An autonomous unmanned ground vehicle (UGV) capable of navigating stealthily at night in off-road and on-road terrain could significantly increase the safety and success rate of such resupply missions for warfighters. Passive night-time perception of terrain and obstacle features is a vital requirement for such missions. As part of the ONR 30 Autonomy Team, the Jet Propulsion Laboratory developed a passive, low-cost night-time perception system under the ONR Expeditionary Maneuver Warfare and Combating Terrorism Applied Research program. Using a stereo pair of forward looking LWIR uncooled microbolometer cameras, the perception system generates disparity maps using a local window-based stereo correlator to achieve real-time performance while maintaining low power consumption. To overcome the lower signal-to-noise ratio and spatial resolution of LWIR thermal imaging technologies, a series of pre-filters were applied to the input images to increase the image contrast and stereo correlator enhancements were applied to increase the disparity density. To overcome false positives generated by mixed pixels, noisy disparities from repeated textures, and uncertainty in far range measurements, a series of consistency, multi-resolution, and temporal based post-filters were employed to improve the fidelity of the output range measurements. The stereo processing leverages multi-core processors and runs under the Robot Operating System (ROS). The night-time passive perception system was tested and evaluated on fully autonomous testbed ground vehicles at SPAWAR Systems Center Pacific (SSC Pacific) and Marine Corps Base Camp Pendleton, California. This paper describes the challenges, techniques, and experimental results of developing a passive, low-cost perception system for night-time autonomous navigation.

  6. Assessing estimates of radiative forcing for solar geoengineering starts with accurate aerosol radiative properties

    Science.gov (United States)

    Dykema, J. A.; Keith, D.; Keutsch, F. N.

    2016-12-01

    The deliberate modification of Earth's albedo as a complement to mitigation in order to slow climate change brings with it a range of risks. A range of different approaches have been studied, including the injection of aerosol particles into the stratosphere to decrease solar energy input into the climate system. Key side effects from this approach include ozone loss and radiative heating. Both of these side effects may produce dynamical changes with further consequences for stratospheric and tropospheric climate. Studies of past volcanic eruptions suggest that sulfate aerosol injection may be capable of achieving a compensating radiative forcing of -1 W m-2 or more. It is also expected that such injection of sulfate aerosols will result in loss of stratospheric ozone and of significant infrared heating. The problems resulting from sulfate aerosols intended have motivated the investigation of alternative materials, including high refractive index solid materials. High refractive index materials have the potential to scatter more efficiently per unit mass, leading to a reduction in surface area for heterogeneous chemistry, and, depending on details of absorption, less radiative heating. Fundamentally, assessing these trade-offs requires accurate knowledge of the complex refractive index of materials being considered over the full range of wavelengths relevant to atmospheric radiative transfer, that is, from ultraviolet to far-infrared. Our survey of the relevant literature finds that such measurements are not available for all materials of interest at all wavelengths. We utilize a method developed in astrophysics to fill in spectral gaps, and find that some materials may heat the stratosphere substantially more than was found in previous work. Stratospheric heating can warm the tropical tropopause layer, increasing the flux of water vapor into the stratosphere, with further consequences for atmospheric composition and radiative forcing. We analyze this consequence

  7. Wave field synthesis of moving virtual sound sources with complex radiation properties.

    Science.gov (United States)

    Ahrens, Jens; Spors, Sascha

    2011-11-01

    An approach to the synthesis of moving virtual sound sources with complex radiation properties in wave field synthesis is presented. The approach exploits the fact that any stationary sound source of finite spatial extent radiates spherical waves at sufficient distance. The angular dependency of the radiation properties of the source under consideration is reflected by the amplitude and phase distribution on the spherical wave fronts. The sound field emitted by a uniformly moving monopole source is derived and the far-field radiation properties of the complex virtual source under consideration are incorporated in order to derive a closed-form expression for the loudspeaker driving signal. The results are illustrated via numerical simulations of the synthesis of the sound field of a sample moving complex virtual source.

  8. High-performance 1024x1024 MWIR/LWIR Dual-band InAs/GaSb Type-II Superlattice-based Camera System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — High performance LWIR detectors are highly needed. In order to image from long distance, it is important that imagers have high sensitivity, high resolution, and...

  9. Optical properties of the PANDA barrel DIRC radiator bars

    Energy Technology Data Exchange (ETDEWEB)

    Kalicy, Grzegorz; Krebs, Marvin; Peters, Klaus [GSI, Darmstadt (Germany); Goethe Universitaet, Frankfurt (Germany); Schwarz, Carsten; Schwiening, Jochen [GSI, Darmstadt (Germany); Collaboration: PANDA-Collaboration

    2015-07-01

    The PANDA experiment at the Facility for Antiproton and Ion Research in Europe (FAIR) at GSI, Darmstadt, will study fundamental questions of hadron physics and QCD. A fast focusing DIRC (Detection of Internally Reflected Cherenkov light) counter will provide hadronic particle identification (PID) in the barrel region of the PANDA detector. To meet the PID requirements, the Barrel DIRC has to provide precise measurements of the Cherenkov angle, which is conserved for Cherenkov photons propagating through the radiator by total internal reflection. The radiators, rectangular bars made from fused silica, have to fulfill very strict optical and mechanical requirements. This includes the squareness and parallelism of the sides of the bars, sharp corners, and a very smooth surface polish, ensuring that the Cherenkov photons reach the optical sensors without angular distortions. Currently the Barrel DIRC is at the final design stage and several different bar shapes and fabrication methods are being considered for the final detector. An optical setup, consisting of a computer-controlled positioning and a multi-wavelength laser system, is used to evaluate the radiator bars to obtain critical values like transmittance and reflectivity. The current results and techniques are presented on this poster.

  10. Effect of gamma radiation on optical and electrical properties of tellurium dioxide thin films

    Indian Academy of Sciences (India)

    T K Maity; S L Sharma

    2008-11-01

    Gamma radiation induced changes in the optical and electrical properties of tellurium dioxide (TeO2) thin films, prepared by thermal evaporation, have been studied in detail. The optical characterization of the as-deposited thin films and that of the thin films exposed to various levels of gamma radiation dose clearly show that the optical bandgap decreases with increase in the gamma radiation dose up to a certain dose. At gamma radiation doses above this value, however, the optical bandgap has been found to increase. On the other hand, the current vs voltage plots for the as-deposited thin films and those for the thin films exposed to various levels of gamma radiation dose show that the current increases with the gamma radiation dose up to a certain dose and that the value of this particular dose depends upon the thickness of the film. The current has, however, been found to decrease with further increase in gamma radiation dose. The observed changes in both the optical and electrical properties indicate that TeO2 thin films can be used as the real time gamma radiation dosimeter up to a certain dose, a quantity that depends upon the thickness of the film.

  11. Statistical and coherence properties of radiation from X-ray free electron lasers

    CERN Document Server

    Saldin, E L; Yurkov, M V

    2009-01-01

    We describe statistical and coherence properties of the radiation from x-ray free electron lasers (XFEL). It is shown that the X-ray FEL radiation before saturation is described with gaussian statistics. Particularly important is the case of the optimized X-ray FEL, studied in detail. Applying similarity techniques to the results of numerical simulations allowed us to find universal scaling relations for the main characteristics of an X-ray FEL operating in the saturation regime: efficiency, coherence time and degree of transverse coherence. We find that with an appropriate normalization of these quantities, they are functions of only the ratio of the geometrical emittance of the electron beam to the radiation wavelength. Statistical and coherence properties of the higher harmonics of the radiation are highlighted as well.

  12. State of the art of AIM LWIR and VLWIR MCT 2D focal plane detector arrays for higher operating temperatures

    Science.gov (United States)

    Figgemeier, H.; Hanna, S.; Eich, D.; Mahlein, K.-M.; Fick, W.; Schirmacher, W.; Thöt, R.

    2016-05-01

    In this paper AIM presents its latest results on both n-on-p and p-on-n low dark current planar MCT photodiode technology LWIR and VLWIR two-dimensional focal plane detector arrays with a cut-off wavelength >11μm at 80K and a 640x512 pixel format at a 20μm pitch. Thermal dark currents significantly reduced as compared to `Tennant's Rule 07' at a yet good detection efficiency >60% as well as results from NETD and photo response performance characterization are presented. The demonstrated detector performance paces the way for a new generation of higher operating temperature LWIR MCT FPAs with a <30mK NETD up to a 110K detector operating temperature and with good operability.

  13. Development of paints with infrared radiation reflective properties

    Directory of Open Access Journals (Sweden)

    Eliane Coser

    2015-06-01

    Full Text Available AbstractLarge buildings situated in hot regions of the Globe need to be agreeable to their residents. Air conditioning is extensively used to make these buildings comfortable, with consequent energy consumption. Absorption of solar visible and infrared radiations are responsible for heating objects on the surface of the Earth, including houses and buildings. To avoid excessive energy consumption, it is possible to use coatings formulated with special pigments that are able to reflect the radiation in the near- infrared, NIR, spectrum. To evaluate this phenomenon an experimental study about the reflectivity of paints containing infrared-reflective pigments has been made. By irradiating with an IR source and by measuring the surface temperatures of the samples we evaluated: color according to ASTM D 2244-14, UV/VIS/NIR reflectance according to ASTM E 903-12 and thermal performance. Additionally, the spectral reflectance and the IR emittance were measured and the solar reflectance of the samples were calculated. The results showed that plates coated with paints containing IR-reflecting pigments displayed lower air temperature on the opposite side as compared to conventional coatings, indicating that they can be effective to reflect NIR and decrease the temperature of buildings when used in roofs and walls.

  14. Study of radiation detection properties of GaN pn diode

    Science.gov (United States)

    Sugiura, Mutsuhito; Kushimoto, Maki; Mitsunari, Tadashi; Yamashita, Kohei; Honda, Yoshio; Amano, Hiroshi; Inoue, Yoku; Mimura, Hidenori; Aoki, Toru; Nakano, Takayuki

    2016-05-01

    Recently, GaN, which has remarkable properties as a material for optical devices and high-power electron devices, has also attracted attention as a material for radiation detectors. We previously suggested the use of BGaN as a neutron detector material. However, the radiation detection characteristics of GaN itself are not yet adequately understood. For realizing a BGaN neutron detector, the understanding of the radiation detection characteristics of GaN, which is a base material of the neutron detector, is important. In this study, we evaluated the radiation detection characteristics of GaN. We performed I-V and energy spectrum measurements under alpha ray, gamma ray, and thermal neutron irradiations to characterize the radiation detection characteristics of a GaN diode. The obtained results indicate that GaN is an effective material for our proposed new BGaN-based neutron detector.

  15. Effect of Ionizing Beta Radiation on the Mechanical Properties of Poly(ethylene under Thermal Stress

    Directory of Open Access Journals (Sweden)

    Bednarik Martin

    2016-01-01

    Full Text Available It was found in this study, that ionizing beta radiation has a positive effect on the mechanical properties of poly(ethylene. In recent years, there have been increasing requirements for quality and cost effectiveness of manufactured products in all areas of industrial production. These requirements are best met with the polymeric materials, which have many advantages in comparison to traditional materials. The main advantages of polymer materials are especially in their ease of processability, availability, and price of the raw materials. Radiation crosslinking is one of the ways to give the conventional plastics mechanical, thermal, and chemical properties of expensive and highly resistant construction polymers. Several types of ionizing radiation are used for crosslinking of polymers. Each of them has special characteristics. Electron beta and photon gamma radiation are used the most frequently. The great advantage is that the crosslinking occurs after the manufacturing process at normal temperature and pressure. The main purpose of this paper has been to determine the effect of ionizing beta radiation on the tensile modulus, strength and elongation of low and high density polyethylene (LDPE and HDPE. These properties were examined in dependence on the dosage of the ionizing beta radiation (non-irradiated samples and those irradiated by dosage 99 kGy were compared and on the test temperature. Radiation cross-linking of LDPE and HDPE results in increased tensile strength and modulus, and decreased of elongation. The measured results indicate that ionizing beta radiation treatment is effective tool for improvement of mechanical properties of LDPE and HDPE under thermal stress.

  16. Properties and recrystallization of radiation damaged pyrochlore and titanite

    Energy Technology Data Exchange (ETDEWEB)

    Zietlow, Peter

    2016-11-02

    Radiation damage in minerals is caused by the alpha-decay of incorporated radionuclides, such as U and Th and their decay products. The effect of thermal annealing (400-1400 K) on radiation-damaged pyrochlores has been investigated by Raman scattering, X-ray powder diffraction (XRD), and combined differential scanning calorimetry/thermogravimetry (DSC/TG) (Zietlow et al., in print). The analysis of three natural radiation-damaged pyrochlore samples from Miass/Russia (6.4 wt% Th, 23.1.10{sup 18} a-decay events per gram (dpg)), Zlatoust/Russia (6.3 wt% Th, 23.1.10{sup 18} dpg), Panda Hill/Tanzania (1.6 wt% Th, 1.6.10{sup 18} dpg), and Blue River/Canada (10.5 wt% U, 115.4.10{sup 18} dpg), are compared with a crystalline reference pyrochlore from Schelingen (Germany). The type of structural recovery depends on the initial degree of radiation damage (Panda Hill 28 %, Blue River 85 %, Zlatoust and Miass 100 % according to XRD), as the recrystallization temperature increases with increasing degree of amorphization. Raman spectra indicate reordering on the local scale during annealing-induced recrystallization. As Raman modes around 800 cm{sup -1} are sensitive to radiation damage (Vandenborre and Husson 1983, Moll et al. 2011), the degree of local order was deduced from the ratio of the integrated intensities of the sum of the Raman bands between 605 and 680 cm{sup -1} devided by the sum of the integrated intensities of the bands between 810 and 860 cm{sup -1}. The most radiation damaged pyrochlores (Miass and Zlatoust) show an abrupt recovery of both, its short- (Raman) and long-range order (X-ray) between 800 and 850 K. The volume decrease upon recrystallization in Zlatoust pyrochlore was large enough to crack the sample repeatedly. In contrast, the weakly damaged pyrochlore (Panda Hill) begins to recover at considerably lower temperatures (near 500 K), extending over a temperature range of ca. 300 K, up to 800 K (Raman). The pyrochlore from Blue River shows in its

  17. Effect of UV/EB radiation dosages on the properties of nanocomposite coatings

    Energy Technology Data Exchange (ETDEWEB)

    Nik Salleh, Nik Ghazali, E-mail: Nik_Ghazali@nuclearmalaysia.gov.m [Malaysian Nuclear Agency, Block 42, Radiation Curing and Synthesis Group, Bangi, 43000 Kajang, Selangor (Malaysia); Firdaus Yhaya, Mohd; Hassan, Azman; Abu Bakar, Aznizam; Mokhtar, Munirah [Faculty of Chemical and Natural Resources Engineering, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor (Malaysia)

    2011-02-15

    The aim of this study was to compare the effects of ultraviolet (UV) and electron beam (EB) radiation on the properties of cured nanocomposite coatings. Surface hardness increased with increase in radiation dosages (number of passes) for all samples. This was due to the increase in crosslinking with increase in radiation dosage. Pendulum hardness, gel content, and thumb twist results were analyzed to choose appropriate curing dosage for both curing techniques. The selected dosages were then used to cure coatings for scratch and abrasion resistance tests. It was found that the UV curing produced coatings with better abrasion resistance, whereas EB curing was a more suitable approach for producing scratch resistance coatings.

  18. The optical properties of equatorial cirrus in the pilot radiation observation experiment

    Energy Technology Data Exchange (ETDEWEB)

    Platt, C.M.R.; Young, S.A.; Manson, P.; Patterson, G.R. [CSIRO, Victoria (Australia)] [and others

    1996-04-01

    The development of a sensitive filter radiometer for the Atmospheric Radiation Measurement (ARM) Program has been reported. The aim was to develop a reliable and fast instrument that could be used alongside a lidar to obtain near realtime optical properties of clouds, particularly high ice clouds, as they drifted over an ARM Cloud and Radiation Testbed (CART) site allowing calculation of the radiation divergence in the atmosphere over the site. Obtaining cloud optical properties by the lidar/radiometer, or LIRAD, method was described by Platt et al.; the latter paper also describes a year`s data on mid-latitude cirrus. The optical properties of equatorial cirrus (i.e., cirrus within a few degrees of the equator) have hardly been studied at all. The same is true of tropical cirrus, although a few observations have been reported by Davis and Platt et al.This paper describes obersvations performed on cirrus clouds, analysis methods used, and results.

  19. Surface radiation properties of ThO/sub 2/ and other reactor materials

    Energy Technology Data Exchange (ETDEWEB)

    Chan, S.H.; Ma, H.H.

    1979-12-01

    This technical report summarizes the results obtained on surface radiation properties of ThO/sub 2/ and other related reactor materials. Specifically, the present study provides surface radiation properties of three nuclear reactor materials; thorium dioxide, sodium and steel (99 Fe + 1 C). First, based on transmission spectra and Kramers-Kronig analysis, the complex refractive index, which is fundamental to surface radiation property calculations, of ThO/sub 2/ is presented over a wide spectral range. Then depending on the contacting media, three types of the surface are considered. They are the interfaces between ThO/sub 2/ and Sodium, ThO/sub 2/ and Steel (99 Fe + 1 C) as well as ThO/sub 2/ and a gas. For each interface, the spectral interface reflectance from one side of the medium to the other side is evaluated for all wavelengths.

  20. Radiation dose dependent change in physiochemical, mechanical and barrier properties of guar gum based films.

    Science.gov (United States)

    Saurabh, Chaturbhuj K; Gupta, Sumit; Bahadur, Jitendra; Mazumder, S; Variyar, Prasad S; Sharma, Arun

    2013-11-06

    Mechanical and water vapor barrier properties of biodegradable films prepared from radiation processed guar gum were investigated. Films prepared from GG irradiated up to 500 Gy demonstrated significantly higher tensile strength as compared to non-irradiated control films. This improvement in tensile strength observed was demonstrated to be due to the ordering of polymer structures as confirmed by small angle X-ray scattering analysis. Exposure to doses higher than 500 Gy, however, resulted in a dose dependent decrease in tensile strength. A dose dependent decrease in puncture strength with no significant differences in the percent elongation was also observed at all the doses studied. Water vapor barrier properties of films improved up to 15% due to radiation processing. Radiation processing at lower doses for improving mechanical and barrier properties of guar based packaging films is demonstrated here for the first time. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Luminescence properties of porcelain ceramics relevant to restrospective radiation dosimetry

    DEFF Research Database (Denmark)

    Bøtter-Jensen, L.; Markey, B.G.; Poolton, N.R.J.

    1996-01-01

    . This appears to arise from the fact that OSL is potentially stimulated in a variety of component phases of the ceramic, and these phases vary from sample to sample. This article reports an initial attempt at characterising the luminescence properties of widely available porcelain wares manufactured under...

  2. Measured comparison of the inversion periods for polarimetric and conventional thermal long-wave IR (LWIR) imagery

    Science.gov (United States)

    Felton, M.; Gurton, K. P.; Roth, L. E.; Pezzaniti, J. L.; Chenault, D. B.

    2009-08-01

    We report the results of a multi-day diurnal study in which radiometrically calibrated polarimetric and conventional thermal imagery is recorded in the LWIR to identify/compare the respective time periods in which minimum target contrast is achieved, e.g., thermal inversion periods are typically experienced during dusk and dawn. Imagery is recorded with a polarimetric IR sensor employing a 324x256 microbolometer array using a spinning achromatic retarder to perform the polarimetric filtering. The images used in this study include the S0, normalized S1, and normalized S2 Stokes images and the degree of linear polarization (DOLP) images of a scene containing military vehicles and the natural background. In addition, relevant meteorological parameters measured during the test period include air temperature, ambient loading in the LWIR, relative humidity, and cloud cover, height and density. The data shows that the chief factors affecting polarimetric contrast are the amount of thermal emission from the objects in the scene and the abundance of LWIR sources in the optical background. In addition, we found that contrast between targets and background within polarimetric images often remains relatively high during periods of low thermal contrast.

  3. Tracking properties of the ATLAS Transition Radiation Tracker (TRT)

    CERN Document Server

    Krasnopevtsev, Dimitriy; The ATLAS collaboration

    2016-01-01

    The tracking performance parameters of the ATLAS Transition Radiation Tracker (TRT) as part of the ATLAS Inner Detector are described for different data taking conditions in proton-proton, proton-lead and heavy ion collisions at the Large Hadron Collider (LHC). These studies are performed using data collected during the first and the second periods of LHC operation and are compared with Monte Carlo simulations. The performance of the TRT, operating with different gas mixtures (Xenon-based and Argon-based) and for high track multiplicities is presented. These studies show that the tracking performance of the TRT with these two gas mixtures is similar and that the detector still provides a significant contribution to the particle momentum measurement of the overall Inner Detector of the ATLAS experiment.

  4. Study on inverse estimation of radiative properties from directional radiances by using statistical RPSO algorithm

    Science.gov (United States)

    Han, Kuk-Il; Kim, Do-Hwi; Choi, Jun-Hyuk; Kim, Tae-Kuk; Shin, Jong-Jin

    2016-09-01

    Infrared signals are widely used to discriminate objects against the background. Prediction of infrared signal from an object surface is essential in evaluating the detectability of the object. Appropriate and easy method of procurement of the radiative properties such as the surface emissivity, bidirectional reflectivity is important in estimating infrared signals. Direct measurement can be a good choice but a costly and time consuming way of obtaining the radiative properties for surfaces coated with many different newly developed paints. Especially measurement of the bidirectional reflectivity usually expressed by the bidirectional reflectance distribution function (BRDF) is the most costly job. In this paper we are presenting an inverse estimation method of the radiative properties by using the directional radiances from the surface of concern. The inverse estimation method used in this study is the statistical repulsive particle swarm optimization (RPSO) algorithm which uses the randomly picked directional radiance data emitted and reflected from the surface. In this paper, we test the proposed inverse method by considering the radiation from a steel plate surface coated with different paints at a clear sunny day condition. For convenience, the directional radiance data from the steel plate within a spectral band of concern are obtained from the simulation using the commercial software, RadthermIR, instead of the field measurement. A widely used BRDF model called as the Sandford-Robertson(S-R) model is considered and the RPSO process is then used to find the best fitted model parameters for the S-R model. The results obtained from this study show an excellent agreement with the reference property data used for the simulation for directional radiances. The proposed process can be a useful way of obtaining the radiative properties from field measured directional radiance data for surfaces coated with or without various kinds of paints of unknown radiative

  5. Measurement of axial radiation properties in Z-pinch dynamic hohlraum at Julong-1

    Science.gov (United States)

    Meng, Shijian; Hu, Qingyuan; Ning, Jiaming; Ye, Fan; Huang, Zhanchang; Qin, Yi; Wang, Dong; Xu, Zeping; Xu, Rongkun

    2017-01-01

    Axial radiation properties in Z-pinch dynamic hohlraum is investigated experimentally for the first time at Julong-1 facility in China, employing a load that contains a cylindrical CHO foam placed at the central axis position of the nested tungsten wire array. Time-resolved axially radiating images indicate that the velocity of the radiating shock is 31.9 ± 5.6 cm/μs in shot 0181. At t = -6.5 ns with respect to the peak of radially radiated power at stagnation, the annular width is estimated to be ˜1 mm and the intensities distribution in the shock implies a good azimuthal symmetry of radiation pressure. Axial power is found to peak prior to the arrival of the shock to the axis, which is explained by the balance between shock heating and radiating cooling. Utilizing the end-on radiation images and axial power, the peak radiation temperature in dynamic hohlraum is obtained to be ˜65 eV.

  6. Chemical structure and physical properties of radiation-induced crosslinking of polytetrafluoroethylene

    Energy Technology Data Exchange (ETDEWEB)

    Oshima, Akihiro E-mail: aks@taka.jaeri.go.jp; Ikeda, Shigetoshi; Katoh, Etsuko; Tabata, Yoneho

    2001-07-01

    The chemical structure and physical properties of polytetrafluoroethylene (PTFE) that has been crosslinked by radiation have been studied by various methods. It has been found that a Y-type crosslinking structure and a Y-type structure incorporating a double bond (modified Y-type) is formed in PTFE by radiation-crosslinking in the molten state. In addition, various types of double bond structures, excluding the crosslinking site, have been identified. The crosslinked PTFE has a good light transparency due to the loss of crystallites, whilst it retains the excellent properties of electrical insulation and heat resistance. The coefficient of abrasion and the permanent creep are also greatly improved by crosslinking.

  7. Influence of radiation on the properties of solar cells

    OpenAIRE

    Zdravković Miloš R.; Vasić Aleksandra I.; Radosavljević Radovan Lj.; Vujisić Miloš Lj.; Osmokrović Predrag V.

    2011-01-01

    The wide substitution of conventional types of energy by solar energy lies in the rate of developing solar cell technology. Silicon is still the mostly used element for solar cell production, so efforts are directed to the improvement of physical properties of silicon structures. There are several trends in the development of solar cells, but mainly two directions are indicated: the improvement of the conventional solar cell characteristics based on semiconductor materials, and explorin...

  8. Radiation shielding properties of concretes including quiclime (CaO)

    Science.gov (United States)

    Özavcı, S.; ćetin, B.

    2017-02-01

    Lime is one of the oldest binder material used for concrete production. In this study, the shielding properties of γ-rays by Quicklime concretes have been investigated for concretes containing different rates of wood ash, küfenki stones, disbudak tree leaf juice and water. Measurements performed using a gamma spectrometer that contains an NaI(Tl) detector and MCA at 662, 1173 and 1332 keV.

  9. Mineral Classification of Land Surface Using Multispectral LWIR and Hyperspectral SWIR Remote-Sensing Data. A Case Study over the Sokolov Lignite Open-Pit Mines, the Czech Republic

    Directory of Open Access Journals (Sweden)

    Gila Notesco

    2014-07-01

    Full Text Available Remote-sensing techniques offer an efficient alternative for mapping mining environments and assessing the impacts of mining activities. Airborne multispectral data in the thermal region and hyperspectral data in the optical region, acquired with the Airborne Hyperspectral Scanner (AHS sensor over the Sokolov lignite open-pit mines in the Czech Republic, were analyzed. The emissivity spectrum was calculated for each vegetation-free land pixel in the longwave infrared (LWIR-region image using the surface-emitted radiation, and the reflectance spectrum was derived from the visible, near-infrared and shortwave-infrared (VNIR–SWIR-region image using the solar radiation reflected from the surface, after applying atmospheric correction. The combination of calculated emissivity, with the ability to detect quartz, and SWIR reflectance spectra, detecting phyllosilicates and kaolinite in particular, enabled estimating the content of the dominant minerals in the exposed surface. The difference between the emissivity values at λ = 9.68 µm and 8.77 µm was found to be a useful index for estimating the relative amount of quartz in each land pixel in the LWIR image. The absorption depth at around 2.2 µm in the reflectance spectra was used to estimate the relative amount of kaolinite in each land pixel in the SWIR image. The resulting maps of the spatial distribution of quartz and kaolinite were found to be in accordance with the geological nature and origin of the exposed surfaces and demonstrated the benefit of using data from both thermal and optical spectral regions to map the abundance of the major minerals around the mines.

  10. Influence of crystallization conditions on the tensile properties of radiation crosslinked, vitamin E stabilized UHMWPE.

    Science.gov (United States)

    George, A; Ngo, H D; Bellare, A

    2014-12-01

    Radiation crosslinking for ultra-high molecular weight polyethylene results in improved wear resistance but a reduction in mechanical properties. Incorporation of vitamin E has been known to decrease the rate of oxidative degradation occurring through radiation crosslinking and prevents the need for post-irradiation melting with subsequent loss of crystallinity. In this study, we aimed to determine the effect of thermal treatments prior to crosslinking on the morphology and tensile properties of vitamin-E-containing polyethylene. Vitamin-E-blended polyethylene was melted and subsequently quenched in ice water in order to induce high rate crystallization. A second group was additionally annealed at 126°C following quenching and all samples were irradiated using electron beam radiation to a dose of 100kGy. The morphology of control, quenched and quench-annealed polyethylene was characterized using small angle x-ray scattering and differential scanning calorimetry. Tensile properties of these polyethylenes were measured before and after radiation crosslinking with equilibrium swelling experiments performed to assess the crosslink density of irradiated samples. This study shows how the tensile properties of polyethylene can be enhanced by varying thermal treatments prior to crosslinking; and thus how it may be possible to offset the reduction in tensile properties afforded by the crosslinking process.

  11. Impact of morphology on the radiative properties of fractal soot aggregates

    Science.gov (United States)

    Doner, Nimeti; Liu, Fengshan

    2017-01-01

    The impact of morphology on the radiative properties of fractal soot aggregates was investigated using the discrete dipole approximation (DDA). The optical properties of four different types of aggregates of freshly emitted soot with a fractal dimension Df=1.65 and a fractal pre-factor kf=1.76 were calculated. The four types of aggregates investigated are formed by uniform primary particles in point-touch, by uniform but overlapping primary particles, by uniform but enlarged primary particles in point-touch, and formed by point-touch and polydisperse primary particles. The radiative properties of aggregates consisting of N=20, 56 and 103 primary particles were numerically evaluated for a given refractive index at 0.532 and 1.064 μm. The radiative properties of soot aggregates vary strongly with the volume equivalent radius aeff and wavelength. The accuracy of DDA was evaluated in the first and fourth cases against the generalized multi-sphere Mie (GMM) solution in terms of the vertical-vertical differential scattering cross section (Cvv). The model predicted the average relative deviations from the base case to be within 15-25% for Cvv, depending on the number of particles for the aggregate. The scattering cross sections are only slightly affected by the overlapping but more significantly influenced by primary particle polydispersity. It was also found that the enlargement of primary particles by 20% has a strong effect on soot aggregate radiative properties.

  12. Correlation of Radiation Dosage With Mechanical Properties of Thin Films

    Science.gov (United States)

    Newton, R. L.

    2003-01-01

    The objective of this investigation was to examine the relationship between irradiation level (proton dose), microstructure, and stress levels in chemical vapor deposited diamond and polysilicon film using crosssectioned specimens. However, the emphasis was placed on the diamond specimen because diamond holds much promise for use in advanced technologies. The use of protons allows not only the study of the charged particle that may cause the most microstructural damage in Earth-orbit microelectromechanical systems (MEMS) devices, but also allows the study of relatively deeply buried damage inside the diamond material. Using protons allows these studies without having to resort to megaelectronvolt implant energies that may create extensive damage due to the high energy that is needed for the implantation process. Since 1 MEMS devices operating in space will not have an opportunity to reverse radiation damage via annealing, only nonannealed specimens were investigated. The following three high spatial resolution techniques were used to examine these relationships: (I) Scanning electron microscopy, (2) micro-Raman spectroscopy, and (3) micro x-ray diffraction.

  13. Radiation hydrolysate of tuna cooking juice with enhanced antioxidant properties

    Science.gov (United States)

    Choi, Jong-il; Sung, Nak-Yun; Lee, Ju-Woon

    2012-08-01

    Tuna protein hydrolysates are of increasing interest because of their potential application as a source of bioactive peptides. Large amounts of tuna cooking juice with proteins and extracts are produced during the process of tuna canning, and these cooking juice wastes cause environmental problems. Therefore, in this study, cooking juice proteins were hydrolyzed by irradiation for their utilization as functional additives. The degree of hydrolysis of tuna cooking juice protein increased from 0% to 15.1% at the absorbed doses of 50 kGy. To investigate the antioxidant activity of the hydrolysate, it was performed the ferric reducing antioxidant power (FRAP) assay, and the lipid peroxidation inhibitory and superoxide radical scavenging activities were measured. The FRAP values increased from 1470 μM to 1930 μM and IC50 on superoxide anion was decreased from 3.91 μg/mL to 1.29 μg/mL at 50 kGy. All of the antioxidant activities were increased in the hydrolysate, suggesting that radiation hydrolysis, which is a simple process that does not require an additive catalysts or an inactivation step, is a promising method for food and environmental industries.

  14. Tracking properties of the ATLAS Transition Radiation Tracker (TRT)

    CERN Document Server

    Krasnopevtsev, Dimitrii; The ATLAS collaboration

    2016-01-01

    The tracking performance parameters of the ATLAS Transition Radiation Tracker (TRT) as part of the ATLAS Inner Detector (ID) are described for different data taking conditions in proton-proton collisions at the Large Hadron Collider (LHC). These studies are performed using data collected during the first (Run 1) and the second (Run 2) periods of LHC operation and are compared with Monte Carlo simulations. The performance of the TRT, operating with Xe-based (Xe-based) and Argon-based (Ar-based) gas mixtures and its dependence on the TRT occupancy is presented. No significant degradation of position measurement accuracy was found up to occupancies of about 20\\% in Run 1. The relative number of reconstructed tracks in ID that also have a extension in the TRT was observed to be almost constant with the increase of occupancies up to 50\\%. Even in configurations where tracks are close to each other, the reconstruction algorithm is still able to find the correct TRT hits and properly reconstruct the tracks.

  15. The Impacts of Optical Properties on Radiative Forcing Due to Dust Aerosol

    Institute of Scientific and Technical Information of China (English)

    WANG Hong; SHI Guangyu; LI Shuyan; LI Wei; WANG Biao; HUANG Yanbin

    2006-01-01

    There are large uncertainties in the quantitative assessment of radiative effects due to atmospheric dust aerosol. The optical properties contribute much to those uncertainties. The authors perform several sensitivity experiments to estimate the impacts of optical characteristics on regional radiative forcing in this paper. The experiments involve in refractive indices, single scattering albedo, asymmetry factor and optical depth. An updated dataset of refractive indices representing East Asian dust and the one recommended by the World Meteorology Organization (WMO) are contrastively analyzed and used. A radiative transfer code for solar and thermal infrared radiation with detailed aerosol parameterization is employed. The strongest emphasis is on the refractive indices since other optical parameters strongly depend on it, and the authors found a strong sensitivity of radiative forcing on refractive indices. Studies show stronger scattering, weaker absorption and forward scattering of the East Asian dust particles at solar wavelengths, which leads to higher negative forcing, lower positive forcing and bigger net forcing at the top of the atmosphere (TOA) than that of the WMO dust model. It is also found that the TOA forcings resulting from these two dust models have opposite signs in certain regions, which implies the importance of accurate measurements of optical properties in the quantitative estimation of radiative forcing.

  16. VIS-NIR, SWIR and LWIR Imagery for Estimation of Ground Bearing Capacity

    Science.gov (United States)

    Fernández, Roemi; Montes, Héctor; Salinas, Carlota

    2015-01-01

    Ground bearing capacity has become a relevant concept for site-specific management that aims to protect soil from the compaction and the rutting produced by the indiscriminate use of agricultural and forestry machines. Nevertheless, commonly known techniques for its estimation are cumbersome and time-consuming. In order to alleviate these difficulties, this paper introduces an innovative sensory system based on Visible-Near InfraRed (VIS-NIR), Short-Wave InfraRed (SWIR) and Long-Wave InfraRed (LWIR) imagery and a sequential algorithm that combines a registration procedure, a multi-class SVM classifier, a K-means clustering and a linear regression for estimating the ground bearing capacity. To evaluate the feasibility and capabilities of the presented approach, several experimental tests were carried out in a sandy-loam terrain. The proposed solution offers notable benefits such as its non-invasiveness to the soil, its spatial coverage without the need for exhaustive manual measurements and its real time operation. Therefore, it can be very useful in decision making processes that tend to reduce ground damage during agricultural and forestry operations. PMID:26083227

  17. FSR: a field portable spectral reflectometer to measure ground from NIR to LWIR

    Science.gov (United States)

    Moreau, Louis; Bourque, Hugo; Ouellet, Réal; Prel, Florent; Roy, Claude; Vallieres, Christian; Thériault, Guillaume

    2011-11-01

    ABB Bomem has recently designed a field-deployable reflectometer. The Full Spectrum Reflectometer (FSR) measures the diffuse reflectance of surfaces in the 0.7 μm to 13.5 μm spectral range. The spectral resolution is adjustable from 32 to 4 cm-1. The instrument is portable, battery-operated and designed for field usage in a single, lightweight and ruggedized package. In its simplest mode, the instrument is automated and can be operated by non-specialist personnel with minimal training. The FSR has a laboratory mode to measure targets brought to the instrument in a sampling cup and a field mode with automated measurement sequence. To facilitate the measurement of various ground surfaces, the instrument is packaged in a three-point mount for easy target access and stability. One of the mount is the sampling port. The instrument has its own built-in NIR and LWIR infrared sources to illuminate the ground area to be measured. The instrument includes two built-in references for calibration: a Spectralon diffuser and an Infragold diffuser. The first units were commissioned to build a spectral database of surfaces in various conditions (humidity, temperature, texture, mixing, etc.) and in the presence of interfering chemicals (oils, solvents, etc.) but the instrument can also serve other purposes such as the identification of unknown materials.

  18. Detection and tracking of RC model aircraft in LWIR microgrid polarimeter data

    Science.gov (United States)

    Ratliff, Bradley M.; LeMaster, Daniel A.; Mack, Robert T.; Villeneuve, Pierre V.; Weinheimer, Jeffrey J.; Middendorf, John R.

    2011-10-01

    The LWIR microgrid Polarized InfraRed Advanced Tactical Experiment (PIRATE) sensor was used to image several types of RC model aircraft at varying ranges and speeds under different background conditions. The data were calibrated and preprocessed using recently developed microgrid processing algorithms prior to estimation of the thermal (s0) and polarimetric (s1 and s2) Stokes vector images. The data were then analyzed to assess the utility of polarimetric information when the thermal s0 data is augmented with s1 and s2 information for several model aircraft detection and tracking scenarios. Multi-variate analysis tools were applied in conjunction with multi-hypothesis detection schemes to assess detection performance of the aircraft under different background clutter conditions. We find that polarization is able to improve detection performance when compared with the corresponding thermal data in nearly all cases. A tracking algorithm was applied to a sequence of s0 and corresponding degree of linear polarization (DoLP) images. An initial assessment was performed to determine whether polarization information can provide additional utility in these tracking scenarios.

  19. Advances in III-V based dual-band MWIR/LWIR FPAs at HRL

    Science.gov (United States)

    Delaunay, Pierre-Yves; Nosho, Brett Z.; Gurga, Alexander R.; Terterian, Sevag; Rajavel, Rajesh D.

    2017-02-01

    Recent advances in superlattice-based infrared detectors have rendered this material system a solid alternative to HgCdTe for dual-band sensing applications. In particular, superlattices are attractive from a manufacturing perspective as the epitaxial wafers can be grown with a high degree of lateral uniformity, low macroscopic defect densities (processed over the last two years. To assess the FPA performance, noise equivalent temperature difference (NETD) measurements were conducted at 80K, f/4.21 and using a blackbody range of 22°C to 32°C. For the MWIR band, the NETD was 27.44 mK with a 3x median NETD operability of 99.40%. For the LWIR band, the median NETD was 27.62 mK with a 3x median operability of 99.09%. Over the course of the VISTA program, HRL fabricated over 30 FPAs with similar NETDs and operabilities in excess of 99% for both bands, demonstrating the manufacturability and high uniformity of III-V superlattices. We will also present additional characterization results including blinkers, spatial stability, modulation transfer function and thermal cycles reliability.

  20. New target acquisition task for contemporary operating environments: personnel in MWIR, LWIR, and SWIR

    Science.gov (United States)

    Boettcher, Evelyn J.; Leonard, Kevin R.; Hodgkin, Van A.; Thompson, Roger; Miller, Brian; Hixson, Jon; Johnson, Sara; Godbolt, Tehran; Acton, David D.

    2010-04-01

    Operating environments that US Soldiers and Marines are in have changed, along with the types of tasks that they are required to perform. In addition, the potential imaging sensor options available have increased. These changes make it necessary to examine how these new tasks are affected by waveband and time of day. US Army Research, Development and Engineering Command, Communications Electronics Research Development and Engineering Center, Night Vision and Electronic Sensor Directorate (NVESD), investigated one such task for several wavebands (MWIR, LWIR, Visible, and SWIR) and during both day and night. This task involved identification of nine different personnel targets: US Soldier, US Marine, Eastern-European/Asian Soldier, Urban Insurgent, Rural Insurgent, Hostile Militia, Indigenous Inhabitant, Contract Laborer, and Reporter. These nine distinct targets were made up from three tactically significant categories: Friendly Force, Combatant and Neutral/Non-Combatant. A ten second video was taken of an actor dressed as one of these targets. The actors walk a square pattern, enabling all aspects to be seen in each video clip. Target characteristics were measured and characteristic dimension, target contrast tabulated. A nine-alternative, forced-choice human perception test was performed at NVESD. This test allowed NVESD to quantify the ability of observers to discriminate between personnel targets for each waveband and time of day. The task difficulty criterion, V50, was also calculated allowing for future modeling using the NVESD sensor performance model.

  1. VIS-NIR, SWIR and LWIR Imagery for Estimation of Ground Bearing Capacity

    Directory of Open Access Journals (Sweden)

    Roemi Fernández

    2015-06-01

    Full Text Available Ground bearing capacity has become a relevant concept for site-specific management that aims to protect soil from the compaction and the rutting produced by the indiscriminate use of agricultural and forestry machines. Nevertheless, commonly known techniques for its estimation are cumbersome and time-consuming. In order to alleviate these difficulties, this paper introduces an innovative sensory system based on Visible-Near InfraRed (VIS-NIR, Short-Wave InfraRed (SWIR and Long-Wave InfraRed (LWIR imagery and a sequential algorithm that combines a registration procedure, a multi-class SVM classifier, a K-means clustering and a linear regression for estimating the ground bearing capacity. To evaluate the feasibility and capabilities of the presented approach, several experimental tests were carried out in a sandy-loam terrain. The proposed solution offers notable benefits such as its non-invasiveness to the soil, its spatial coverage without the need for exhaustive manual measurements and its real time operation. Therefore, it can be very useful in decision making processes that tend to reduce ground damage during agricultural and forestry operations.

  2. The utilize of gamma radiation on the examination of mechanical properties of polymeric materials

    OpenAIRE

    F. Greškovič; Varga, J.; Ľ. Dulebová

    2012-01-01

    The article deals about the application area of radiation crosslinking of plastics, which follows after the injection moulding. The main objective of the presented article is the research of influence irradiation dosage on mechanical properties of materials: PP filled by 15 % of mineral filler – talc. Mechanical properties - tensile strength and impact strength by Charpy were examined in dependence on absorbed dose of the gamma rays on various conditions and were compared with non-irradiated ...

  3. Dielectric and Radiative Properties of Sea Foam at Microwave Frequencies: Conceptual Understanding of Foam Emissivity

    OpenAIRE

    Gaiser, Peter W.; Anguelova, Magdalena D.

    2012-01-01

    Foam fraction can be retrieved from space-based microwave radiometric data at frequencies from 1 to 37 GHz. The retrievals require modeling of ocean surface emissivity fully covered with sea foam. To model foam emissivity well, knowledge of foam properties, both mechanical and dielectric, is necessary because these control the radiative processes in foam. We present a physical description of foam dielectric properties obtained from the foam dielectric constant including foam skin depth; foam ...

  4. Radiation processing of indigenous natural polymers. Properties of radiation modified blends from sago-starch for biodegradable composite

    Energy Technology Data Exchange (ETDEWEB)

    Ghazali, Z.; Dahlan, K.Z. [Malaysian Institute for Nuclear and Technology Research (MINT), Bangi, Kajang (Malaysia); Wongsuban, B.; Idris, S.; Muhammad, K. [Universiti Putra Malaysia, Faculty of Food Science and Biotechnology, Department of Food Science, Serdang (Malaysia)

    2001-03-01

    Research and development on biodegradable polymer blends and composites have gained wider interest to offer alternative eco-friendly products. Natural polysaccharide such as sago-starch offers the most promising raw material for the production of biodegradable composites. The potential of sago, which is so abundant in Malaysia, to produce blends for subsequent applications in composite material, was evaluated and explored. Blends with various formulations of sago starch and polyvinyl alcohol (PVA), and polyvinyl pyrrolidone (PVP) polymers were prepared and subjected to radiation modification using electron beam irradiation. The effect of irradiation on the sago and its blends was evaluated and their properties were characterized. The potential of producing composite from sago blends was explored. Foams from these blends were produced using microwave oven while films were produced through casting method. The properties such as mechanical, water absorption, expansion ratio, and biodegradability were characterized and reported in this paper. (author)

  5. Spectroscopic comparison of effects of electron radiation on mechanical properties of two polyimides

    Science.gov (United States)

    Long, Edward R., Jr.; Long, Sheila Ann T.

    1987-01-01

    The differences in the radiation durabilities of two polyimide materials, Du Pont Kapton and General Electric Ultem, are compared. An explanation of the basic mechanisms which occur during exposure to electron radiation from analyses of infrared (IR) and electron paramagnetic resonance (EPR) spectroscopic data for each material is provided. The molecular model for Kapton was, in part, established from earlier modeling for Ultem (pp. 1293-1298 of IEEE Transactions on Nuclear Science, December 1984). Techniques for understanding the durability of one complex polymer based on the understanding of a different and equally complex polymer are demonstrated. The spectroscopic data showed that the primary radiation-generated change in the tensile properties of Ultem (a large reduction in tensile elongation) was due to crosslinking, which followed the capture by phenyl radicals of hydrogen atoms removed from gem-dimethyl groups. In contrast, the tensile properties of Kapton remained unchanged because radical-radical recombination, a self-mending process, took place.

  6. Effect of laser radiation on physicochemical and functional properties of human hemoglobin in vitro

    NARCIS (Netherlands)

    Irzhak, LI; Zotova, EA; Mamaeva, SA

    1997-01-01

    Exposure to laser radiation increases pH and isoelectric point of human hemoglobin solution, improves the acid-base properties, increases affinity for oxygen, and decreases the Bohr effect in comparison with intact hemoglobin. The mechanisms underlying these changes are discussed.

  7. Search for new scintillators by studying the fluorescence properties of powdered compounds with synchrotron radiation.

    Science.gov (United States)

    Dewu, W; Jianfei, L; Yaning, X; Yifan, G; Yu, C; Hancheng, S; Jiashan, Z; Zuqi, Z

    1995-03-01

    This paper describes a method for investigating the properties of powdered compounds using synchrotron X-radiation. The fluorescence decay times of bismuth germanate, BaF(2), CeF(3) and CsI, as well as the light yields of several samples of gadolinium silicate, prepared in different ways, have been measured.

  8. A comparison of radiation shielding of stainless steel with different magnetic properties

    Directory of Open Access Journals (Sweden)

    Calik Adnan

    2014-01-01

    Full Text Available The radiation shielding properties of three different stainless steels have been investigated. For this purpose, linear attenuation coefficients at photon energy levels of 662 keV and 1250 keV have been measured. The obtained results showed that ferritic stainless steel was more capable in stopping the high energy photons than its non-magnetic counterpart.

  9. The Sensitivity of Diagnostic Radiative Properties to Cloud Microphysics among Cloud-Resolving Model Simulations.

    Science.gov (United States)

    Xu, Kuan-Man

    2005-04-01

    This study examines the sensitivity of diagnosed radiative fluxes and heating rates to different treatments of cloud microphysics among cloud-resolving models (CRMs). The domain-averaged CRM outputs are used in this calculation. The impacts of the cloud overlap and uniform hydrometeor assumptions are examined using outputs having spatially varying cloud fields from a single CRM. It is found that the cloud overlap assumption impacts the diagnosis more significantly than the uniform hydrometeor assumption for all radiative fluxes. This is also the case for the longwave radiative cooling rate except for a layer above 7 km where it is more significantly impacted by the uniform hydrometeor assumption. The radiative cooling above upper-tropospheric anvils and the warming below these clouds are overestimated by about 0.5 K day-1 using the domain-averaged outputs. These results are used to further quantify intermodel differences in radiative properties due to different treatments of cloud microphysics among 10 CRMs. The magnitudes of the intermodel differences, as measured by the deviations from the consensus of 10 CRMs, are found to be smaller than those due to the cloud overlap assumption and comparable to those due to the uniform hydrometeor assumption for most shortwave radiative fluxes and the net radiative fluxes at the top of the atmosphere (TOA) and at the surface. For all longwave radiative fluxes, they are smaller than those due to cloud overlap and uniform hydrometeor assumptions. The consensus of all diagnosed radiative fluxes except for the surface downward shortwave flux agrees with observations to a degree that is close to the uncertainties of satellite- and ground-based measurements.

  10. Properties of radiation synthesized PVP-kappa carrageenan hydrogel blends[PVP; Carrageenan; Hydrogels; Radiation crosslinking; Radiation grafting; Semi-interpenetrating network

    Energy Technology Data Exchange (ETDEWEB)

    Abad, L.V. E-mail: lvabad@pnri.dost.gov.ph; Relleve, L.S.; Aranilla, C.T.; Rosa, A.M. dela

    2003-12-01

    Hydrogels have been synthesized from varying concentrations of polyvinyl pyrolidone (PVP) and kappa carrageenan (KC) using gamma radiation. Physical properties such as gel fraction and swelling behavior were determined. Data revealed the presence of a network structure whereby KC is physically entangled into the crosslinked PVP (SIPN). TGA, X-RF and FT-IR analyses of the gel fractions also indicated grafting and crosslinking of the PVP. The degree of grafting and crosslinking depended on the concentrations of KC and PVP. Maximum grafting was obtained at higher KC concentration and lower PVP.

  11. Radiation induced oxidative degradation of polymers—III. Effect of radiation on mechanical properties

    Science.gov (United States)

    Seguchi, Tadao; Arakawa, Kazuo; Ito, Masayuki; Hayakawa, Naohiro; Machi, Sueo

    The changes of mechanical properties of various kinds of polyethylene (PE) and ethylene-propylene copolymer (EPR) with the irradiation in air, in oxygen of 10 atm, and under vacuum were investigated. The decrease in the elongation ( E b) and the tensile strength ( T b) of PE by the irradiation in oxygen is larger than under vacuum. The changes of E b well reflect the degradation of PE. In case of EPR, the T b decreases sharply with dose in any environments, and the E b decreases under vacuum to a larger extent than in oxygen. The modulus at 200% elongation of EPR increases with dose under vacuum, but decreases in oxygen. When the samples were irradiated in air, the changes of the mechanical properties were the intermediate between oxygen and vacuum and dependent on the ratio of oxidation and non-oxidation layers in the film. The antioxidant (Irganox 1010 or DPPD) mixed in polymers was found to retard effectively the polymer degradation by the irradiation in oxygen.

  12. Cloud Scavenging Effects on Aerosol Radiative and Cloud-nucleating Properties - Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Ogren, John A.; Sheridan, Patrick S.; Andrews, Elisabeth

    2009-03-05

    The optical properties of aerosol particles are the controlling factors in determining direct aerosol radiative forcing. These optical properties depend on the chemical composition and size distribution of the aerosol particles, which can change due to various processes during the particles’ lifetime in the atmosphere. Over the course of this project we have studied how cloud processing of atmospheric aerosol changes the aerosol optical properties. A counterflow virtual impactor was used to separate cloud drops from interstitial aerosol and parallel aerosol systems were used to measure the optical properties of the interstitial and cloud-scavenged aerosol. Specifically, aerosol light scattering, back-scattering and absorption were measured and used to derive radiatively significant parameters such as aerosol single scattering albedo and backscatter fraction for cloud-scavenged and interstitial aerosol. This data allows us to demonstrate that the radiative properties of cloud-processed aerosol can be quite different than pre-cloud aerosol. These differences can be used to improve the parameterization of aerosol forcing in climate models.

  13. Radiation Effects in Flow through Porous Medium over a Rotating Disk with Variable Fluid Properties

    Directory of Open Access Journals (Sweden)

    Shalini Jain

    2016-01-01

    Full Text Available The present study investigates the radiation effects in flow through porous medium over a permeable rotating disk with velocity slip and temperature jump. Fluid properties density (ρ, viscosity (μ, and thermal conductivity (κ are taken to be dependent on temperature. Particular case considering these fluid properties’ constant is also discussed. The governing partial differential equations are converted into nonlinear normal differential equation using similarity alterations. Transformed system of equations is solved numerically by using Runge-Kutta method with shooting technique. Effects of various parameters such as porosity parameter K, suction parameter Ws, rotational Reynolds number Re, Knudsen number Kn, Prandtl number Pr, radiation parameter N, and relative temperature difference parameter ε on velocity profiles along radial, tangential, and axial direction and temperature distribution are investigated for both variable fluid properties and constant fluid properties. Results obtained are analyzed and depicted through graphs and table.

  14. Thermal radiative properties of metamaterials and other nanostructured materials: A review

    Institute of Scientific and Technical Information of China (English)

    Ceji FU; Zhuomin M. ZHANG

    2009-01-01

    The ability to manufacture, control, and manipulate structures at extremely small scales is the hallmark of modem technologies, including microelec-tronics, MEMS/NEMS, and nano-biotechnology. Along with the advancement of microfabrication technology, more and more investigations have been performed in recent years to understand the influence of microstructures on radiative properties. The key to the enhancement of performance is through the modification of the reflection and transmission properties of electromagnetic waves and thermal emission spectra using one-, two-, or three-dimensional micro/nanostructures. This review focuses on recent developments in metamaterials-manmade mate-rials with exotic optical properties, and other nanostruc-tured materials, such as gratings and photonic crystals, for application in radiative energy transfer and energy conversion systems.

  15. Crystal Properties and Radiation Effects in Solid Molecular Hydrogens

    Energy Technology Data Exchange (ETDEWEB)

    Kozioiziemski, B

    2000-09-01

    The crystal lattice structure, growth shapes and helium generated by beta-decay of solid deuterium-tritium (D-T) mixtures have been studied. Understanding of these D-T properties is important for predicting and optimizing the target design of the National Ignition Facility (NIF). Raman spectroscopy showed the D-T crystal structure is hexagonal close packed, common to the non-tritiated isotopes. The isotopic mixtures of both tritiated and non-tritiated species broadens the rotational transitions, especially of the lighter species in the mixture. The vibrational frequencies of each isotope is shifted to higher energy in the mixture than the pure components. The J = 1-0 population decreases exponentially with a 1/e time constant which rapidly increases above 10.5 K for both D{sub 2} and T{sub 2} in D-T. The conversion rate is nearly constant from 5 K to 10 K for both D{sub 2} and T{sub 2} at 7.1 hours and 2.1 hours, respectively. The smoothing of D-T layers by beta decay heating is limited by the crystal surface energy. Deuterium and hydrogen-deuteride crystals were grown at a number of temperatures below the triple point to determine the surface energy and roughening transition. Several distinct crystal shapes were observed on a number of different substrates. The a facet roughens between 0.9 T{sub TP} and T{sub TP}, while the c facet persists up to the melting temperature. This is very different from the behavior of the other rare gas crystals which grow completely rounded above 0.8 T{sub TP}. Helium bubbles formed as a product of the beta decay were observed using optical microscopy and the diffusion of smaller bubbles measured with dynamic light scattering. Bubble diffusion coefficients as high as 2.0 x 10{sup -16} m{sup 2}/s were measured for 10-50 nm bubbles. The bubbles move in response to a thermal gradient, with speeds between 1 {micro}m/hour and 100 {micro}m/hour for thermal gradients and temperatures appropriate to NIF targets.

  16. Infrared radiative properties of alumina up to the melting point: A first-principles study

    Science.gov (United States)

    Yang, J. Y.; Xu, M.; Liu, L. H.

    2016-11-01

    The high thermal emission of alumina dominates the radiative heat transfer of rocket exhaust plume. Yet numerous experimental measurements on radiative properties of alumina at high temperatures vary considerably from each other and cannot provide physical insight into the underlying mechanism. In this work, the ab initio molecular dynamics (AIMD) method and ab initio parameterized Drude model are combined to predict the radiative properties of alumina for temperatures up to 2327 K (the melting point) in the spectral range 1-12 μm. Contributed by different microscopic processes, the optical absorption of alumina in the spectral range 1-4 and 4-12 μm is described by two distinct methods. In the spectral range 4-12 μm, the multi-phonon process mainly contributes to optical absorption and can be simulated by the AIMD method based on the linear response theory. While in the spectral range 1-4 μm, the optical absorption is mainly caused by intrinsic carriers and can be effectively described by the ab initio parameterized Drude model. The first-principles calculations can successfully predict the infrared radiative properties of alumina at high temperatures and well reproduce the literature experiments. Moreover, the theoretical simulations verify that alumina can retain its semiconducting character even in the liquid phase and there emerges sharp increase in the near-infrared optical absorption of alumina upon melting.

  17. Properties of BGO thin films under the influence of gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Arshak, K. [Electronic and Computer Engineering Department, University of Limerick, Limerick (Ireland)], E-mail: khalil.arshak@ul.ie; Korostynska, O.; Harris, J. [Electronic and Computer Engineering Department, University of Limerick, Limerick (Ireland); Morris, D.; Arshak, A. [Physics Department, University of Limerick, Limerick (Ireland); Jafer, E. [Electronic and Computer Engineering Department, University of Limerick, Limerick (Ireland)

    2008-02-15

    It is important to know the behaviour of materials under the influence of radiation for the effective design of novel sensor systems. Optical properties of bismuth germinate (Bi{sub 4}Ge{sub 3}O{sub 12}-BGO) thin films were investigated in terms of their perception to gamma radiation exposure. An Edwards E306A vacuum thermal coating system was used for thin films deposition. BGO films with a thickness of 200 nm were exposed to a disk-type {sup 137}Cs gamma radiation source with an activity of 370 kBq. Optical properties of the films were investigated using CARY IE UV-Visible Spectrophotometer. Calculated optical band gap for as-deposited BGO thin film was 1.95 eV. Gamma radiation induced changes in the optical properties of thin films, which could be explained by the variation in the degree of disorder. From the density-of-state model, it is known that optical band gap decreases with an increasing degree of disorder of the amorphous phase. Electrical properties of BGO thin films were recorded in real time using a low power capacitive interface system with a high resolution, which is based on Delta-sigma modulator. At doses from 0 to 1.5 mGy little if any changes in the capacitance were measured. This could be explained by co-existence of two processes, namely creation and annihilation of defects under the influence of radiation. After a threshold dose of 1.5 mGy creation of defects becomes more prevailing and the BGO film capacitance has gradually increased in value from 2.97 pF to 7.09 pF after irradiation with a 2.44 mGy dose.

  18. Implementation of pixel level digital TDI for scanning type LWIR FPAs

    Science.gov (United States)

    Ceylan, Omer; Kayahan, Huseyin; Yazici, Melik; Afridi, Sohaib; Shafique, Atia; Gurbuz, Yasar

    2014-07-01

    Implementation of a CMOS digital readout integrated circuit (DROIC) based on pixel level digital time delay integration (TDI) for scanning type LWIR focal plane arrays (FPAs) is presented. TDI is implemented on 8 pixels with over sampling rate of 3. Analog signal integrated on integration capacitor is converted to digital domain in pixel, and digital data is transferred to TDI summation counters, where contributions of 8 pixels are added. Output data is 16 bit, where 8 bits are allocated for most significant bits and 8 bits for least significant bits. Control block of the ROIC, which is responsible of generating timing diagram for switches controlling the pixels and summation counters, is realized with VerilogHDL. Summation counters and parallel-to-serial converter to convert 16 bit parallel output data to single bit output are also realized with Verilog HDL. Synthesized verilog netlists are placed&routed and combined with analog under-pixel part of the design. Quantization noise of analog-to-digital conversion is less than 500e-. Since analog signal is converted to digital domain in-pixel, inaccuracies due to analog signal routing over large chip area is eliminated. ROIC is fabricated with 0.18μm CMOS process and chip area is 10mm2. Post-layout simulation results of the implemented design are presented. ROIC is programmable through serial or parallel interface. Input referred noise of ROIC is less than 750 rms electron, while power consumption is less than 30mW. ROIC is designed to perform in cryogenic temperatures.

  19. Implementation of electronic crosstalk correction for terra MODIS PV LWIR bands

    Science.gov (United States)

    Geng, Xu; Madhavan, Sriharsha; Chen, Na; Xiong, Xiaoxiong

    2015-09-01

    The MODerate-resolution Imaging Spectroradiometer (MODIS) is one of the primary instruments in the fleet of NASA's Earth Observing Systems (EOS) in space. Terra MODIS has completed 15 years of operation far exceeding its design lifetime of 6 years. The MODIS Level 1B (L1B) processing is the first in the process chain for deriving various higher level science products. These products are used mainly in understanding the geophysical changes occurring in the Earth's land, ocean, and atmosphere. The L1B code is designed to carefully calibrate the responses of all the detectors of the 36 spectral bands of MODIS and provide accurate L1B radiances (also reflectances in the case of Reflective Solar Bands). To fulfill this purpose, Look Up Tables (LUTs), that contain calibration coefficients derived from both on-board calibrators and Earth-view characterized responses, are used in the L1B processing. In this paper, we present the implementation mechanism of the electronic crosstalk correction in the Photo Voltaic (PV) Long Wave InfraRed (LWIR) bands (Bands 27-30). The crosstalk correction involves two vital components. First, a crosstalk correction modular is implemented in the L1B code to correct the on-board Blackbody and Earth-View (EV) digital number (dn) responses using a linear correction model. Second, the correction coefficients, derived from the EV observations, are supplied in the form of LUTs. Further, the LUTs contain time stamps reflecting to the change in the coefficients assessed using the Noise Equivalent difference Temperature (NEdT) trending. With the algorithms applied in the MODIS L1B processing it is demonstrated that these corrections indeed restore the radiometric balance for each of the affected bands and substantially reduce the striping noise in the processed images.

  20. Effect of radiation processing on nutritional, functional, sensory and antioxidant properties of red kidney beans

    Science.gov (United States)

    Marathe, S. A.; Deshpande, R.; Khamesra, Arohi; Ibrahim, Geeta; Jamdar, Sahayog N.

    2016-08-01

    In the present study dry red kidney beans (Phaseolus vulgaris), irradiated in the dose range of 0.25-10.0 kGy were evaluated for proximate composition, functional, sensory and antioxidant properties. Radiation processing up to 10 kGy did not affect proximate composition, hydration capacity and free fatty acid value. All the sensory attributes were unaffected at 1.0 kGy dose. The dose of 10 kGy, showed lower values for odor and taste, however, they were in acceptable range. Significant improvement in textural quality and reduction in cooking time was observed at dose of 10 kGy. Antioxidant activity of radiation processed samples was also assessed after normal processing such as soaking and pressure cooking. Both phenolic content and antioxidant activity evaluated in terms of DPPH free radical scavenging assay and inhibition in lipid peroxidation using rabbit erythrocyte ghost system, were marginally improved (5-10%) at the dose of 10 kGy in dry and cooked samples. During storage of samples for six months, no significant change was observed in sensory, cooking and antioxidant properties. Thus, radiation treatment of 1 kGy can be applied to get extended shelf life of kidney beans with improved functional properties without impairing bioactivity; nutritional quality and sensory property.

  1. The effects of proton radiation on UHMWPE material properties for space flight and medical applications

    Science.gov (United States)

    Cummings, Chad S.; Lucas, Eric M.; Marro, Justin A.; Kieu, Tri M.; DesJardins, John D.

    2011-11-01

    Ultra High Molecular Weight Polyethylene (UHMWPE) is a polymer widely used as a radiation shielding material in space flight applications and as a bearing material in total joint replacements. As a long chain hydrocarbon based polymer, UHMWPE's material properties are influenced by radiation exposure, and prior studies show that gamma irradiation is effective for both medical sterilization and increased wear resistance in total joint replacement applications. However, the effects of space flight radiation types and doses on UHMWPE material properties are poorly understood. In this study, three clinically relevant grades of UHMWPE (GUR 1020, GUR 1050, and GUR 1020 blended with Vitamin E) were proton irradiated and tested for differences in material properties. Each of the three types of UHMWPE was irradiated at nominal doses of 0 Gy (control), 5 Gy, 10 Gy, 20 Gy, and 35 Gy. Following irradiation, uniaxial tensile testing and thermal testing using Differential Scanning Calorimetry (DSC) and Dynamic Mechanical Analysis (DMA) were performed. Results show small but significant changes in several material properties between the control (0 Gy) and 35 Gy samples, indicating that proton irradiation could have a effect on the long term performance of UHMWPE in both medical and space flight applications.

  2. Observations of Three-Dimensional Radiative Effects that Influence Satellite Retrievals of Cloud Properties

    Science.gov (United States)

    Varnai, Tamas; Marshak, Alexander; Lau, William K. M. (Technical Monitor)

    2001-01-01

    This paper examines three-dimensional (3D) radiative effects, which arise from horizontal radiative interactions between areas that have different cloud properties. Earlier studies have argued that these effects can cause significant uncertainties in current satellite retrievals of cloud properties, because the retrievals rely on one-dimensional (1D) theory and do not consider the effects of horizontal changes in cloud properties. This study addresses two questions: which retrieved cloud properties are influenced by 3D radiative effects, and where 3D effects tend to occur? The influence of 3D effects is detected from the wayside illumination and shadowing make clouds appear asymmetric: Areas appear brighter if the cloud top surface is tilted toward, rather than away from, the Sun. The analysis of 30 images by the Moderate Resolution Imaging Spectroradiometer (MODIS) reveals that retrievals of cloud optical thickness and cloud water content are most influenced by 3D effects, whereas retrievals of cloud particle size are much less affected. The results also indicate that while 3D effects are strongest at cloud edges, cloud top variability in cloud interiors, even in overcast regions, also produces considerable 3D effects. Finally, significant 3D effects are found in a wide variety of situations, ranging from thin clouds to thick ones and from low clouds to high ones.

  3. Aerosol Optical Properties and Its Radiative Forcing over Yulin, China in 2001 and 2002

    Institute of Scientific and Technical Information of China (English)

    CHE Huizheng; ZHANG Xiaoye; Stephane ALFRARO; Bernadette CHATENET; Laurent GOMES; ZHAO Jianqi

    2009-01-01

    The aerosol optical properties and direct radiative forcing over the Mu Us desert of northern China, acquired through a CE318 sunphotometer of the ground-bascd Aerosol Robotic Network (AERONET), are analyzed. The seasonal variations in the aerosol optical properties are examined. The effect of meteorological elements (pressure, temperature, water vapor pressure, relative humidity and wind speed) on the aerosol optical properties is also studied. Then, the sources and optical properties under two different cases, a dust event and a pollution event, are compared. The results show that the high aerosol optical depth (AOD) found in Yulin was mostly attributed to the occurrence of dust events in spring from the Mu Us desert and deserts of West China and Mongolia, as well as the impacts of anthropogenic pollutant particles from the middle part of China in the other seasons. The seasonal variation and the probability distribution of the radiative forcing and the radiative forcing efficiency at the surface and the top of the atmosphere are analyzed and regressed using the linear and Gaussian regression methods.

  4. The role of InAs thickness on the material properties of InAs/GaSb superlattices

    Science.gov (United States)

    Haugan, H. J.; Brown, G. J.; Szmulowicz, F.; Elhamri, S.; Olson, B. V.; Boggess, T. F.; Grazulis, L.

    2011-09-01

    The epitaxial growth parameters optimized for mid-wavelength infrared (MWIR) InAs/GaSb superlattice (SL) growth are not directly applicable for long-wavelength infrared (LWIR) SL growth. We observed a two orders of magnitude drop in the spectral intensity of the measured photoresponse (PR) as the InAs layer thickness in the SL increases from 9 monolayers (MLs) to 16 MLs for a fixed GaSb layer thickness of 7 MLs. However, the theoretically calculated absorption strength decreases only by about a factor of two. So other factors affecting photoresponse, such as carrier mobility and lifetime, are likely responsible for the large drop in the PR of the LWIR SL in this sample set. In fact the measured Hall properties of MWIR and LWIR SLs are very different, with holes as the majority carriers in MWIR SLs and electrons as the majority carriers in LWIR SLs. Therefore we investigated the charge carrier density, carrier mobility, and carrier recombination dynamics in LWIR SL samples. Specifically we used temperature-dependent Hall effect and time-resolved pump-probe measurements to study the effect of adjusting several growth parameters on the background carrier concentrations and studied carrier lifetimes in LWIR SLs.

  5. Temporal Variability of Aerosol Properties during TCAP: Impact on Radiative Forcing

    Energy Technology Data Exchange (ETDEWEB)

    Kassianov, Evgueni I.; Barnard, James C.; Pekour, Mikhail S.; Berg, Larry K.; Fast, Jerome D.; Michalsky, Joseph J.; Lantz, K.; Hodges, G. B.

    2013-11-01

    Ground-based remote sensing and in situ observations of aerosol microphysical and optical properties have been collected during summertime (June-August, 2012) as part of the Two-Column Aerosol Project (TCAP; http://campaign.arm.gov/tcap/), which was supported by the U.S. Department of Energy’s (DOE’s) Atmospheric Radiation Measurement (ARM) Program (http://www.arm.gov/). The overall goal of the TCAP field campaign is to study the evolution of optical and microphysical properties of atmospheric aerosol transported from North America to the Atlantic and their impact on the radiation energy budget. During TCAP, the ground-based ARM Mobile Facility (AMF) was deployed on Cape Cod, an arm-shaped peninsula situated on the easternmost portion of Massachusetts (along the east coast of the United States) and that is generally downwind of large metropolitan areas. The AMF site was equipped with numerous instruments for sampling aerosol, cloud and radiative properties, including a Multi-Filter Rotating Shadowband Radiometer (MFRSR), a Scanning Mobility Particle Sizer (SMPS), an Aerodynamic Particle Sizer (APS), and a three-wavelength nephelometer. In this study we present an analysis of diurnal and day-to-day variability of the column and near-surface aerosol properties obtained from remote sensing (MFRSR data) and ground-based in situ measurements (SMPS, APS, and nephelometer data). In particular, we show that the observed diurnal variability of the MFRSR aerosol optical depth is strong and comparable with that obtained previously from the AERONET climatology in Mexico City, which has a larger aerosol loading. Moreover, we illustrate how the variability of aerosol properties impacts the direct aerosol radiative forcing at different time scales.

  6. MWIR/LWIR filter based on Liquid-Crystal Fabry-Perot structure for tunable spectral imaging detection

    Science.gov (United States)

    Zhang, Huaidong; Muhammad, Afzal; Luo, Jun; Tong, Qing; Lei, Yu; Zhang, Xinyu; Sang, Hongshi; Xie, Changsheng

    2015-03-01

    An electrically tunable medium-wave infrared (MWIR)/long-wave infrared (LWIR) filter based on the key structure of Liquid-Crystal (LC) Fabry-Perot (FP), which works in the wavelength range from 2.5 μm to 12 μm, is designed and fabricated successfully in this paper. According to the optical interference principle of the FP cavity and electrically controlled birefringence of nematic LC molecules, the particular functions including spectral selection and spectral staring and spectral adjustment, can be realized by the developed MWIR/LWIR filter driven and controlled electrically. As to the LC-FP filter, both planar reflective mirrors are shaped by depositing a layer of aluminum (Al) film (∼60 nm) over one side of double-side polished Zinc Selenide (ZnSe) wafer (∼1 mm), and then polyimide (PI) layer with the thickness of ∼100 nm is coated directly on Al film. With typical sandwich architecture, the depth of the cavity with nematic LC molecules sealed in is ∼7.5 μm. To make sure the LC molecules parallel aligned and twist regularly under voltage driving signal applied on Al film, which also acts as electrode, the V-grooves are formed in PI layer with the depth of ∼90 nm and the width of ∼350 nm at average by strong rubbing. The typical transmission spectrum in MWIR&LWIR wavelength range and several spectral images in MWIR wavelength range based on the fabricated LC-FP filter, have been obtained through applying a voltage driving-signal with different root-means-square (RMS) value over the electrodes of LC-FP filter in the selected voltage range from 0VRMS to 19.8VRMS. The testing result demonstrates a prospect of realization smart spectral imaging and further integrating the LC-FP filter with infrared focal plane arrays (FPAs) to achieve the purpose infrared multispectral imaging. The developed MWIR&LWIR LC-FP filters show some obvious advantages such as wide working wavelength range, electrically tunable spectral selection, ultra-compact, low cost, being

  7. Radiation properties and hydrodynamics evolution of highly charged ions in laser-produced silicon plasma.

    Science.gov (United States)

    Min, Qi; Su, Maogen; Cao, Shiquan; Sun, Duixiong; O'Sullivan, Gerry; Dong, Chenzhong

    2016-11-15

    We present a simplified radiation hydrodynamic model based on the fluid dynamic equations and the radiative transfer equation, which can be used to investigate the radiation properties and dynamics evolution of highly charged ions in a laser-produced plasma in vacuum. The outputs of the model consist of the evolution of the electron temperature, atom, and ion density, and the temporal and spatial evolution of various transient particles in plasma, as well as the simulated spectrum related to certain experimental conditions in a specified spectral window. In order to test the model and provide valuable experimental feedback, a series of EUV emission spectra of silicon plasmas have been measured using the spatio-temporally resolved laser produced plasma technique. The temporal and spatial evolution of the plasma is reliably reconstructed by using this model.

  8. UV radiation effect towards mechanical properties of Natural Fibre Reinforced Composite material: A Review

    Science.gov (United States)

    Mahzan, Shahruddin; Fitri, Muhamad; Zaleha, M.

    2017-01-01

    The use of natural fibres as reinforcement material have become common in human applications. Many of them are used in composite materials especially in the polymer matrix composites. The use of natural fibres as reinforcement also provide alternative solution of usage instead of being a waste materials. In some applications, these natural reinforced polymer composites were used as the outer layer, making them exposed to ultra violet exposure, hence prone to UV radiation. This paper reviews the effect of UV radiation towards the mechanical properties of natural fibre reinforced polymer matrix composite material. The effect of chemical treatment towards the natural fibre is also investigated. One of the important features that was critically explored was the degradation of the composite materials. The influence of UV radiation on the degradation rate involve several parameters such as wavelength, intensity and exposure time. This review highlights the influence of these parameters in order to provide better solution for polymer matrix composite’s development.

  9. Improved aerosol radiative properties as a foundation for solar geoengineering risk assessment

    Science.gov (United States)

    Dykema, J. A.; Keith, D. W.; Keutsch, F. N.

    2016-07-01

    Side effects resulting from the deliberate injection of sulfate aerosols intended to partially offset climate change have motivated the investigation of alternatives, including solid aerosol materials. Sulfate aerosols warm the tropical tropopause layer, increasing the flux of water vapor into the stratosphere, accelerating ozone loss, and increasing radiative forcing. The high refractive index of some solid materials may lead to reduction in these risks. We present a new analysis of the scattering efficiency and absorption of a range of candidate solid aerosols. We utilize a comprehensive radiative transfer model driven by updated, physically consistent estimates of optical properties. We compute the potential increase in stratospheric water vapor and associated longwave radiative forcing. We find that the stratospheric heating calculated in this analysis indicates some materials to be substantially riskier than previous work. We also find that there are Earth-abundant materials that may reduce some principal known risks relative to sulfate aerosols.

  10. Long-wave infrared radiation reflected by compression stockings in the treatment of cellulite: a clinical double-blind, randomized and controlled study.

    Science.gov (United States)

    Bagatin, E; Miot, H A; Soares, J L M; Sanudo, A; Afonso, J P J M; de Barros Junior, N; Talarico, S

    2013-10-01

    Cellulite refers to changes in skin relief on the thighs and buttocks of women, with a prevalence of 80-90%, causing dissatisfaction and search for treatment. Etiopathogenesis is multifactorial, as follows: herniation of the hypodermis towards the dermis, facilitated by perpendicular fibrous septa, changes in the dermal extracellular matrix, decreased adiponectin, genetic polymorphism, microcirculation alterations and inflammatory process. There are numerous therapeutic approaches, with little evidence of effectiveness. The long-wave infrared (LWIR) radiation interacts with water, improves microcirculation and stimulates metabolic processes. To date, the use of tissues with potential reflection of LWIR radiation has not been systematically investigated as adjuvant treatment for cellulite. To investigate the efficacy and safety of the treatment of cellulite through the use of compression stockings made with thread reflecting LWIR radiation. Clinical study of therapeutic intervention, controlled and double-blind, including 30 women, aging from 25 to 40 years, with cellulite of grades II and III on the thighs and buttocks who used compression stockings, "pantyhose" model, made with reflector thread of LWIR radiation, on only one randomized side. Women under other treatments for cellulite and with venous and/or blood insufficiencies were excluded. Evaluation of efficacy by clinical parameters, photographs, Dermatology Life Quality Index (DLQI), cutometry and high frequency ultrasonography and security by observation of adverse events and venous EcoDoppler recordings. DLQI scores showed significant reduction; the two-dimensional high-frequency ultrasonography showed an insignificant increase in dermal echogenicity as well as other efficacy parameters demonstrated no or slight improvement, with no differences between the sides exposed or not to LWIR; and there were no severe adverse events. Compression stockings, with or without thread reflector of LWIR, showed slight

  11. Absorption Properties of Simply Fabricated All-Metal Mushroom Plasmonic Metamaterials Incorporating Tube-Shaped Posts for Multi-Color Uncooled Infrared Image Sensor Applications

    Directory of Open Access Journals (Sweden)

    Shinpei Ogawa

    2016-03-01

    Full Text Available Wavelength-selective infrared (IR absorbers have attracted considerable interest due to their potential for a wide range of applications. In particular, they can be employed as advanced uncooled IR sensors that identify objects through their radiation spectra. Herein, we propose a mushroom plasmonic metamaterial absorber incorporating tube-shaped metal posts (MPMAT for use in the long-wavelength IR (LWIR region. The MPMAT design consists of a periodic array of thin metal micropatches connected to a thin metal plate via tube-shaped metal posts. Both the micropatches and posts can be constructed simultaneously as a result of the tube-shaped structure of the metal post structure; thus, the fabrication procedure is both simple and low cost. The absorption properties of these MPMATs were assessed both theoretically and experimentally, and the results of both investigations demonstrated that these devices exhibit suitable levels of LWIR absorption regardless of the specific tube-shaped structures employed. It was also found to be possible to tune the absorption wavelength by varying the micropatch width and the inner diameter of the tube-shaped metal posts, and to obtain absorbance values of over 90%. Focal plane array structures based on such MPMATs could potentially serve as high-performance, low-cost, multi-spectral uncooled IR image sensors.

  12. Synthesis and properties of radiation modified thermally cured castor oil based polyurethanes

    Science.gov (United States)

    Mortley, Aba; Bonin, H. W.; Bui, V. T.

    2007-12-01

    Thermally cured polyurethanes were prepared from castor oil and hexamethylene diisocyanate (HMDI). Due to the long aliphatic chain of the castor oil component of polyurethane, thermal curing of castor oil based polyurethane (COPU) is limited by increasing polymer viscosity. To enhance further crosslinking, COPUs were exposed to doses up to 3.0 MGy produced by the mixed ionizing radiation field of a SLOWPOKE-2 research nuclear reactor. The physico-mechanical properties of castor oil based polyurethanes (COPU), unirradiated and irradiated, were characterized by mechanical tensile tests. A four-fold increase in modulus and tensile strength values from 0.930 to 4.365 MPa and 0.149 to 0.747 MPa, respectively, suggests improved physico-mechanical properties resulting from radiation. The changing areas of the carbonyl and the NH absorbance peaks and the disappearance of the isocyanate peak in the FTIR spectra as radiation progressed, indicates increased hydrogen bonding and intermolecular crosslinking, which is in agreement with the mechanical tests. Unchanging 13C solid state NMR spectra imply limited sample degradation with increasing radiation.

  13. Study on the mechanical property of polyimide film in space radiation environments

    Science.gov (United States)

    Shen, Zicai; Mu, Yongqiang; Ding, Yigang; Liu, Yuming; Zhao, Chunqing

    2016-01-01

    Polyimide films are widely used in spacecraft, but their mechanical properties would degrade in space environments, such as electron, proton, near ultraviolet or far ultraviolet, etc. The mechanical property and mechanism of polyimide film in electron, proton, near ultraviolet and far ultraviolet was studied by Φ800 combined space radiation test facility of Beijing Institute of Space Environment Engineering (BISSE. Rupture elongation of Kapton film decrease with the increase of the tensile deformation rate. The tensile strength and the rupture elongation of Kapton film decrease with the increase of electron and proton radiation, while tensile strength and the rupture elongation of Kapton film decrease firstly and then increase with near ultraviolet and far ultraviolet.

  14. Remote assessment of the degree of soil degradation from radiation properties of soils

    Science.gov (United States)

    Romanov, A. N.

    2009-03-01

    The effect of the water and salt contents, the soil texture, and the groundwater level on the radiation properties of soils was studied. A methodology was developed for the remote assessment of the degree of soil degradation on the basis of measuring the brightness temperature and emissivity of soils in the microwave region. Criteria based on the remote measurements of radiation parameters of soils for recording changes in the water-physical and other properties of soils, which are necessary for detecting degradation processes at early stages, were substantiated. For the remote assessment of soil degradation, it was proposed to analyze trends in changes with time concerning the emissivities of unfrozen soils occurring at a positive temperature (depending on the soil water content and the groundwater level), the emissivities of frozen nonsaline soils (depending on the soil texture and thermodynamic temperature), and the brightness temperature (depending on the soil salinity and thermodynamic temperature).

  15. Investigation of efficient termination structure for improved breakdown properties of semiconductor radiation detectors

    Energy Technology Data Exchange (ETDEWEB)

    Krizaj, D.; Resnik, D.; Vrtacnik, D.; Amon, S. [Univ. of Ljubljana (Slovenia). Faculty of Electrical Engineering; Cindro, V. [Jozef Stefan Inst., Ljubljana (Slovenia)

    1998-06-01

    Efficiency of a new junction termination structure for improvement of breakdown properties of semiconductor radiation detectors is investigated. The structure consists of a diffused resistor winding around the active junction in a spiral fashion. The current flow through the spiral enables controlled potential distribution along the spiral turns and thus controlled depletion spreading from the main junction, efficiently preventing premature avalanche breakdown. Both multiple guard-ring structures and spiral junction termination structures have shown good breakdown properties typically three to five times higher than breakdown voltages of diodes without junction termination. The breakdown voltages of spiral junction termination structures are only weakly influenced by changes in substrate doping concentration caused by neutron irradiation. They can thus be considered for termination of future semiconductor radiation detectors.

  16. Effect of Solar Radiation on Viscoelastic Properties of Bovine Leather: Temperature and Frequency Scans

    Science.gov (United States)

    Nalyanya, Kallen Mulilo; Rop, Ronald K.; Onyuka, Arthur S.

    2017-04-01

    This work presents both analytical and experimental results of the effect of unfiltered natural solar radiation on the thermal and dynamic mechanical properties of Boran bovine leather at both pickling and tanning stages of preparation. Samples cut from both pickled and tanned pieces of leather of appropriate dimensions were exposed to unfiltered natural solar radiation for time intervals ranging from 0 h (non-irradiated) to 24 h. The temperature of the dynamic mechanical analyzer was equilibrated at 30°C and increased to 240°C at a heating rate of 5°C \\cdot Min^{-1}, while its oscillation frequency varied from 0.1 Hz to 100 Hz. With the help of thermal analysis (TA) control software which analyzes and generates parameter means/averages at temperature/frequency range, the graphs were created by Microsoft Excel 2013 from the means. The viscoelastic properties showed linear frequency dependence within 0.1 Hz to 30 Hz followed by negligible frequency dependence above 30 Hz. Storage modulus (E') and shear stress (σ ) increased with frequency, while loss modulus (E''), complex viscosity (η ^{*}) and dynamic shear viscosity (η) decreased linearly with frequency. The effect of solar radiation was evident as the properties increased initially from 0 h to 6 h of irradiation followed by a steady decline to a minimum at 18 h before a drastic increase to a maximum at 24 h. Hence, tanning industry can consider the time duration of 24 h for sun-drying of leather to enhance the mechanical properties and hence the quality of the leather. At frequencies higher than 30 Hz, the dynamic mechanical properties are independent of the frequency. The frequency of 30 Hz was observed to be a critical value in the behavior in the mechanical properties of bovine hide.

  17. The influence of different black carbon and sulfate mixing methods on their optical and radiative properties

    Science.gov (United States)

    Zhang, Hua; Zhou, Chen; Wang, Zhili; Zhao, Shuyun; Li, Jiangnan

    2015-08-01

    Three different internal mixing methods (Core-Shell, Maxwell-Garnett, and Bruggeman) and one external mixing method are used to study the impact of mixing methods of black carbon (BC) with sulfate aerosol on their optical properties, radiative flux, and heating rate. The optical properties of a mixture of BC and sulfate aerosol particles are considered for three typical bands. The results show that mixing methods, the volume ratio of BC to sulfate, and relative humidity have a strong influence on the optical properties of mixed aerosols. Compared to internal mixing, external mixing underestimates the particle mass absorption coefficient by 20-70% and the particle mass scattering coefficient by up to 50%, whereas it overestimates the particle single scattering albedo by 20-50% in most cases. However, the asymmetry parameter is strongly sensitive to the equivalent particle radius, but is only weakly sensitive to the different mixing methods. Of the internal methods, there is less than 2% difference in all optical properties between the Maxwell-Garnett and Bruggeman methods in all bands; however, the differences between the Core-Shell and Maxwell-Garnett/Bruggeman methods are usually larger than 15% in the ultraviolet and visible bands. A sensitivity test is conducted with the Beijing Climate Center Radiation transfer model (BCC-RAD) using a simulated BC concentration that is typical of east-central China and a sulfate volume ratio of 75%. The results show that the internal mixing methods could reduce the radiative flux more effectively because they produce a higher absorption. The annual mean instantaneous radiative force due to BC-sulfate aerosol is about -3.18 W/m2 for the external method and -6.91 W/m2 for the internal methods at the surface, and -3.03/-1.56/-1.85 W/m2 for the external/Core-Shell/(Maxwell-Garnett/Bruggeman) methods, respectively, at the tropopause.

  18. Effects of Radiation on the Physical Properties of Superlig 644 Resin

    Energy Technology Data Exchange (ETDEWEB)

    Oji, L.N.

    2001-01-10

    This study evaluated the physical properties and stability of irradiated SuperLig 644 in a simulated salt solution (Envelope A simulant without cesium) exposed to a 60Co gamma radiation source. The primary objective was to examine the physical properties of irradiated resin, such as adhesion, to ascertain if resin irradiated to extremely high doses would exhibit high back-pressure or stick together when sluiced out of a column. This work is in support of the design of cesium-removal ion exchange columns at the Hanford River Protection Project (RPP)

  19. Transmission Properties of THz Radiation Pulses through Very Deep Zero-Order Metallic Gratings

    Institute of Scientific and Technical Information of China (English)

    XING Qi-Rong; LI Shu-Xin; ZHANG Wei-Li; LANG Li-Ying; MAO Fang-Lin; XU Shi-Xiang; CHAI Lu; WANG Qing-Yue

    2005-01-01

    @@ Very deep zero-order metallic grating structures are processed to study the transmission properties of THz radiation pulses. The experiments have been performed with two samples. The delay of the THz pulses and the corresponding resonantly enhanced transmission spectra through the samples are observed. To explain the extraordinary transmission we have treated the samples as Fabry-Perot resonators through resonant excitation of the coupled surface plasmon polaritons filled in the cavities between the metal slats. The experimental results are in reasonable agreement with the numerical simulation. Our results show that THz-time-domain spectroscopy may be an effective technique for studying the optical properties of various THz microstructured devices.

  20. Tensile and tribological properties of high-crystallinity radiation crosslinked UHMWPE

    Energy Technology Data Exchange (ETDEWEB)

    Bistolfi, Alessandro; Turell, Mary Beth; Lee, Ying-Lung; Bellare, Anuj; (BWH)

    2009-09-02

    Osteolysis due to particulate wear debris associated with ultrahigh molecular weight polyethylene (UHMWPE) components of total joint replacement prostheses has been a major factor determining their in vivo lifetime. In recent years, radiation crosslinking has been employed to decrease wear rates in PE components, especially in acetabular cups of total hip replacement prostheses. A drawback of radiation crosslinking is that it leads to a crosslinked PE (or XPE) with lower mechanical properties compared with uncrosslinked PE. In contrast, high-crystallinity PEs are known to have several mechanical properties higher than conventional PE. In this study, we hypothesized that increasing the crystallinity of radiation crosslinked and remelted XPE would result in an increase in tensile properties without compromising wear resistance. High-pressure crystallization was performed on PE and XPE and analyzed for the resulting morphological alterations using differential scanning calorimeter, low voltage scanning electron microscopy, and ultrasmall angle X-ray scattering. Uniaxial tensile tests showed that high-pressure crystallization increased the tensile modulus and yield stress in both PE and XPE, decreased the ultimate strain and ultimate stress in PE but had no significant effect on ultimate strain or ultimate stress in XPE. Multidirectional wear tests demonstrated that high-pressure crystallization decreased the wear resistance of PE but had no effect on the wear resistance of XPE. In conclusion, this study shows that high-pressure crystallization can be effectively used to increase the crystallinity and modulus of XPE without compromising its superior wear resistance compared with PE.

  1. Tensile and tribological properties of high-crystallinity radiation crosslinked UHMWPE.

    Science.gov (United States)

    Bistolfi, Alessandro; Turell, Mary Beth; Lee, Ying-Lung; Bellare, Anuj

    2009-07-01

    Osteolysis due to particulate wear debris associated with ultrahigh molecular weight polyethylene (UHMWPE) components of total joint replacement prostheses has been a major factor determining their in vivo lifetime. In recent years, radiation crosslinking has been employed to decrease wear rates in PE components, especially in acetabular cups of total hip replacement prostheses. A drawback of radiation crosslinking is that it leads to a crosslinked PE (or XPE) with lower mechanical properties compared with uncrosslinked PE. In contrast, high-crystallinity PEs are known to have several mechanical properties higher than conventional PE. In this study, we hypothesized that increasing the crystallinity of radiation crosslinked and remelted XPE would result in an increase in tensile properties without compromising wear resistance. High-pressure crystallization was performed on PE and XPE and analyzed for the resulting morphological alterations using differential scanning calorimeter, low voltage scanning electron microscopy, and ultrasmall angle X-ray scattering. Uniaxial tensile tests showed that high-pressure crystallization increased the tensile modulus and yield stress in both PE and XPE, decreased the ultimate strain and ultimate stress in PE but had no significant effect on ultimate strain or ultimate stress in XPE. Multidirectional wear tests demonstrated that high-pressure crystallization decreased the wear resistance of PE but had no effect on the wear resistance of XPE. In conclusion, this study shows that high-pressure crystallization can be effectively used to increase the crystallinity and modulus of XPE without compromising its superior wear resistance compared with PE.

  2. Effects of agrochemicals, ultra violet stabilisers and solar radiation on the radiometric properties of greenhouse films

    Directory of Open Access Journals (Sweden)

    Giuliano Vox

    2013-10-01

    Full Text Available Agrochemicals, based on iron, sulphur and chlorine, generate by products that lead to a degradation of greenhouse films together with a decrease in their mechanical and physical properties. The degradation due to agrochemicals depends on their active principles, method and frequency of application, and greenhouse ventilation. The aim of the research was to evaluate how agrochemical contamination and solar radiation influence the radiometric properties of ethylene-vinyl acetate copolymer greenhouse films by means of laboratory and field tests. The films, manufactured on purpose with the addition of different light stabiliser systems, were exposed to natural outdoor weathering at the experimental farm of the University of Bari (Italy; 41° 05’ N in the period from 2006 to 2008. Each film was tested for two low tunnels: one low tunnel was sprayed from inside with the agrochemicals containing iron, chlorine and sulphur while the other one was not sprayed and served as control. Radiometric laboratory tests were carried out on the new films and on samples taken at the end of the trials. The experimental tests showed that both the natural weathering together with the agrochemicals did not modify significantly the radiometric properties of the films in the solar and in the photosynthetically active radiation wavelength range. Within six months of experimental field tests the variations in these radiometric characteristics were at most 10%. Significant variations, up to 70% of the initial value, were recorded for the stabilised films in the long-wave infrared radiation wavelength range.

  3. Waste Tire Particles and Gamma Radiation as Modifiers of the Mechanical Properties of Concrete

    Directory of Open Access Journals (Sweden)

    Eduardo Sadot Herrera-Sosa

    2014-01-01

    Full Text Available In polymer reinforced concrete, the Young’s modulus of both polymers and cement matrix is responsible for the detrimental properties of the concrete, including compressive and tensile strength, as well as stiffness. A novel methodology for solving such problems is based on use of ionizing radiation, which has proven to be a good tool for improvement on physical and chemical properties of several materials including polymers, ceramics, and composites. In this work, particles of 0.85 mm and 2.80 mm obtained from waste tire were submitted at 250 kGy of gamma radiation in order to modify their physicochemical properties and then used as reinforcement in Portland cement concrete for improving mechanical properties. The results show diminution on mechanical properties in both kinds of concrete without (or with irradiated tire particles with respect to plain concrete. Nevertheless such diminutions (from 2 to 16% are compensated with the use of high concentration of waste tire particles (30%, which ensures that the concrete will not significantly increase the cost.

  4. J-integral fracture toughness, Tearing modulus and tensile properties of Vitamin E stabilized radiation crosslinked UHMWPE.

    Science.gov (United States)

    Bellare, Anuj; Dorfman, Robert; Samuel, Ashwanth; Thornhill, Thomas S

    2016-08-01

    Radiation crosslinking of ultra-high molecular weight polyethylene (UHMWPE) increases its wear resistance in total joint replacement prostheses. Unfortunately, it is accompanied by a dose-dependent decrease in several mechanical properties. In this study, the tensile properties and fracture behavior of radiation crosslinked, Vitamin E stabilized UHMWPE was studied as a function of radiation dose. The Rice and Sorensen model, applicable to elastic-plastic materials, was utilized to obtain the initial crack driving force, J1c, steady state J-integral fracture toughness, Jss and the Tearing modulus. Tensile tests showed the dependence of tensile properties on radiation dose. Jss of non-crosslinked UHMWPE was higher than for crosslinked UHMWPE׳s but there was no dose dependent change in Jss whereas there was almost no change in J1c over the entire dose range. Finally, a monotonic decrease in Tearing modulus was observed with radiation dose.

  5. Physical Properties of CO2 Frost Formed by Radiative Cooling in a Mars Simulation Chamber

    Science.gov (United States)

    Wood, Stephen; Bruckner, A.; Hansen, G.; Cornwall, C.; Kimber, N.; Alvarez, F.

    2013-10-01

    We have performed realistic laboratory simulations of the thermal and radiative environment at the surface of Mars to produce the first samples of carbon dioxide ice formed as it does on Mars, by radiative cooling from a near-pure CO2 gas. It is important to determine the physical characteristics of Mars' seasonal CO2 polar ice caps because these determine their radiative properties which, in turn, control the polar energy balance and the seasonal variation in global surface pressure. It is not known whether they form as fluffy fine-grained deposits, dense solid ice, or something in between. Previous simulations have used conductive cooling, condensing CO2 onto a substrate cooled by liquid nitrogen (Kieffer 1968, Ditteon and Kieffer 1979). This technique favors the growth of grains having the best thermal contact with the surface, resulting in large grain sizes and a coarse texture. On Mars, however, the latent heat released by condensation must be lost radiatively to space. For this experiment, we have constructed a Mars simulation chamber containing low thermal conductivity analog regolith and low pressure CO2 gas. To grow radiation frost in the laboratory requires simultaneous containment of the atmosphere/vapor while allowing infrared radiation to escape (to balance the latent heat of condensation). Planets accomplish this using gravity to hold down the atmosphere. The key to our simulation is the use of a thin polypropylene film that is largely transparent in the thermal infrared yet strong enough to maintain the required pressure differential between our Mars-like "atmosphere" and the vacuum-enclosed space simulator (a liquid-nitrogen cooled plate). We use internal and external light sources to briefly illuminate the frost and obtain high resolution images of its physical morphology and texture using an in situ fiberscope with an articulated tip. Initial results will be presented.

  6. Effect of a Temperature Mode of Radiation-thermal Sintering the Structure and Magnetic Properties of Mn-Zn-ferrites

    Directory of Open Access Journals (Sweden)

    V.G. Kostishyn

    2015-12-01

    Full Text Available 2000NM Mn-Zn-ferrites have been produced by radiation-thermal sintering (RTS. We have studied the effect of RTS on the electromagnetic properties of ferrites. X-ray diffraction have been used to investigate general aspects of phase transformations during the radiation-thermal sintering of green compacts.

  7. NOAA Climate Data Record (CDR) of Cloud and Clear-Sky Radiation Properties, Version 1.0

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NASA LaRC cloud and clear sky radiation properties dataset is generated using algorithms initially developed for application to TRMM and MODIS imagery within the...

  8. A promising new mechanism of ionizing radiation detection for positron emission tomography: modulation of optical properties

    Science.gov (United States)

    Tao, Li; Daghighian, Henry M.; Levin, Craig S.

    2016-11-01

    Using conventional scintillation detection, the fundamental limit in positron emission tomography (PET) time resolution is strongly dependent on the inherent temporal variances generated during the scintillation process, yielding an intrinsic physical limit for the coincidence time resolution of around 100 ps. On the other hand, modulation mechanisms of the optical properties of a material exploited in the optical telecommunications industry can be orders of magnitude faster. In this paper we borrow from the concept of optics pump-probe measurement to for the first time study whether ionizing radiation can produce modulations of optical properties, which can be utilized as a novel method for radiation detection. We show that a refractive index modulation of approximately 5× {{10}-6} is induced by interactions in a cadmium telluride (CdTe) crystal from a 511 keV photon source. Furthermore, using additional radionuclide sources, we show that the amplitude of the optical modulation signal varies linearly with both the detected event rate and average photon energy of the radiation source.

  9. A new mechanism of ionizing radiation detection for positron emission tomography: modulation of optical properties

    Science.gov (United States)

    Tao, Li; Daghighian, Henry M.; Levin, Craig S.

    2016-10-01

    Using conventional scintillation detection, the fundamental limit in positron emission tomography (PET) annihilation photon pair coincidence time resolution is strongly dependent on the inherent temporal variances generated during the scintillation process, yielding an intrinsic physical limit of around 100 ps. On the other hand, modulation mechanisms of a material's optical properties as exploited in the optical telecommunications industry can be orders of magnitude faster. In this paper we borrow from the concept of optics pump-probe measurement to study whether ionizing radiation can also produce fast modulations of optical properties, which can be utilized as a novel method for radiation detection. We show that a refractive index modulation of approximately 5x10-6 is induced by interactions in a cadmium telluride (CdTe) crystal from a 511 keV photon source. Furthermore, using additional radionuclide sources, we show that the amplitude of the optical modulation signal varies linearly with both the radiation source flux rate and average photon energy.

  10. Parameterization of sea-salt optical properties and physics of the associated radiative forcing

    Science.gov (United States)

    Li, J.; Ma, X.; von Salzen, K.; Dobbie, S.

    2008-08-01

    The optical properties of sea-salt aerosol have been parameterized at shortwave and longwave wavelengths. The optical properties were parameterized in a simple functional form in terms of the ambient relative humidity based on Mie optical property calculations. The proposed parameterization is tested relative to Mie calculations and is found to be accurate to within a few percent. In the parameterization, the effects of the size distribution on the optical properties are accounted for in terms of effective radius of the sea-salt size distribution. This parameterization differs from previous works by being formulated directly with the wet sea-salt size distribution and, to our knowledge, this is the first published sea-salt parameterization to provide a parameterization for both shortwave and longwave wavelengths. We have used this parameterization in a set of idealized 1-D radiative transfer calculations to investigate the sensitivity of various attributes of sea-salt forcing, including the dependency on sea-salt column loading, effective variance, solar angle, and surface albedo. From these sensitivity tests, it is found that sea-salt forcings for both shortwave and longwave spectra are linearly related to the sea-salt loading for realistic values of loadings. The radiative forcing results illustrate that the shortwave forcing is an order of magnitude greater than the longwave forcing results and opposite in sign, for various loadings. Forcing sensitivity studies show that the influence of effective variance for sea-salt is minor; therefore, only one value of effective variance is used in the parameterization. The dependence of sea-salt forcing with solar zenith angle illustrates an interesting result that sea-salt can generate a positive top-of-the-atmosphere result (i.e. warming) when the solar zenith angle is relatively small (i.e. <30°). Finally, it is found that the surface albedo significantly affects the shortwave radiative forcing, with the forcing

  11. VARIATION OF PHYSICO-CHEMICAL PROPERTIES OF RADIATION CROSSLINKED RUBBER WITH STORAGE TIME

    Institute of Scientific and Technical Information of China (English)

    N.C. Dafader; M.E. Haque; F. Akhtar

    2005-01-01

    The effect of storage on physico-chemical properties of non-irradiated natural rubber and radiation vulcanized natural rubber (RVNR) were evaluated. The rubber films were stored under two different conditions, namely in open air and sealed polyethylene bags. The antioxidant, tris(nonylated phenyl) phosphite (TNPP) was used for preventing degradation of RVNR films. Gel content, cross-link density, tensile strength at break and 500% elongation of rubber films were measured.The results show that the retention (%) of tensile properties of rubber films with TNPP is higher than that of rubber films without antioxidants. The rubber films stored in polyethylene bags also show better retention of tensile properties than those of rubber films stored in open air.

  12. Synthesis and properties of p(NIPA-co-NVP)/clay hydrogels by radiation polymerization

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In this study, hydrogels of P(NIPA-co-NVP)/clay were synthesized by γ-ray radiation. Different thermo-sensitive hydrogels were made under different experimental conditions such as dose, monomer ratio, and content of clay. X-ray diffraction shows that the layer distance between Na-clays is changed from 1.6 to 2.7 nm because Na-clay pieces can be intercalated or exfoliated by HTMAB, and that between P(NIPA-co-NVP)/clay pieces is 3.4 nm.The swelling property tests show that the LCST of P(NIPA-co-NVP) is higher than PNIPA. With the increase of NVP content, LCST is higher. As the ratio of NIPA/NVP is 95/5, hydrogel shows the best swelling property and LCST is 37℃. LCST of P(NIPA-co-NVP)/clay hydrogel is not changed, but the strength and swelling properties are better.

  13. Experimental design of mixture applied to study PVP hydrogels properties crosslinked by ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Alcantara, Mara Tania S.; Lugao, Ademar B., E-mail: maratalcantara@uol.com.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Taqueda, Maria Elena S. [Universidade de Sao Paulo (USP), SP (Brazil). Escola Politecnica. Dept. de Engenharia Quimica

    2009-07-01

    Hydrogels are three dimensional hydrophilic crosslinked polymeric networks that have capacity to swell by absorbing water or biological fluids without dissolve. Hydrogels have been widely used in different application fields from agriculture, industry and in biomedicine. The properties of a hydrogel are extremely important in selecting which materials are suitable for a specific application. So mixtures can offer hydrogels with different properties to different applications. The PVP hydrogels were prepared by gamma radiation of an aqueous polymer solution and crosslinked by gamma ray, an effective and simple method for hydrogel formation that offers some advantages over the other techniques. In this work, a mixture experimental design was used to study the relationship between polymer cross-linking and swelling properties of PVP hydrogels with PEG as plasticizer and agar as gellifier. The gel fraction was measured for every mixture specified for the experiment D-optimal designs. (author)

  14. Thermophysical Properties of Selected Aerospace Materials. Part 1. Thermal Radiative Properties

    Science.gov (United States)

    1976-01-01

    Cu, 0.3% Cr, and Al balance [A00005]. Various properties and usage of this alloy is discussed in [T15906] and [A00005]. In the solution-heat...molecular weight of Lucite is of the order of 5 x 105 to over 106 (degree of polymerisation approximately 5000-10000). According to x-ray data...filaments to high temperature usage in composite. In the area of metal matrix, aluminum or aluminum alloys are currently com- mercially available

  15. Overview of ACE-Asia Spring 2001 Investigations on Aerosol Radiative Effects and Related Aerosol Properties

    Science.gov (United States)

    Russell, Philip B.; Valero, F. P. J.; Flatau, P. J.; Bergin, M.; Holben, B.; Nakajima, T.; Pilewskie, P.; Bergstrom, R.; Hipskind, R. Stephen (Technical Monitor)

    2001-01-01

    A primary, ACE-Asia objective was to quantify the interactions between aerosols and radiation in the Asia-Pacific region. Toward this end, radiometric and related aerosol measurements were made from ocean, land, air and space platforms. Models that predict aerosol fields guided the measurements and are helping integrate and interpret results. Companion overview's survey these measurement and modeling components. Here we illustrate how these components were combined to determine aerosol radiative. impacts and their relation to aerosol properties. Because clouds can obscure or change aerosol direct radiative effects, aircraft and ship sorties to measure these effects depended on predicting and finding cloud-free areas and times with interesting aerosols present. Pre-experiment satellite cloud climatologies, pre-flight aerosol and cloud forecasts, and in-flight guidance from satellite imagery all helped achieve this. Assessments of aerosol regional radiative impacts benefit from the spatiotemporal coverage of satellites, provided satellite-retrieved aerosol properties are accurate. Therefore, ACE-Asia included satellite retrieval tests, as part of many comparisons to judge the consistency (closure) among, diverse measurements. Early results include: (1) Solar spectrally resolved and broadband irradiances and optical depth measurements from the C-130 aircraft and at Kosan, Korea yielded aerosol radiative forcing efficiencies, permitting comparisons between efficiencies of ACE-Asia and INDOEX aerosols, and between dust and "pollution" aerosols. Detailed results will be presented in separate papers. (2) Based on measurements of wavelength dependent aerosol optical depth (AOD) and single scattering albedo the estimated 24-h a average aerosol radiative forcing efficiency at the surface for photosynthetically active radiation (400 - 700 nm) in Yulin, China is approx. 30 W sq m per AOD(500 nm). (3) The R/V Brown cruise from Honolulu to Sea of Japan sampled an aerosol optical

  16. Theoretical radiative properties between states of the triplet manifold of NH radical.

    Science.gov (United States)

    Owono Owono, L C; Ben Abdallah, D; Jaidane, N; Lakhdar, Z Ben

    2008-02-28

    Ab initio transition dipole moments between states of the triplet manifold of NH radical are determined at the complete active space self-consistent field, followed by the internally contracted multireference singles plus doubles configuration interaction level of theory with a modified aug-cc-pVTZ basis set that accounts for valence-Rydberg interactions. This enables the computation of various radiative characteristics such as Einstein coefficients, radiative lifetimes, and oscillator strengths. These properties concern as well valence and Rydberg states. For the valence states, only the (0, 0) band of the A 3 Pi-X 3 Sigma(-) transition has received some important amount of attention. Data for the other transitions are rather scarce and sometimes inexistent. The results obtained in this work show good agreement with the available experimental data in comparison to other theoretical numbers reported in the literature.

  17. Radiative properties of diffractively-coupled optical nano-antennas with helical geometry.

    Science.gov (United States)

    Wang, Ren; Forestiere, Carlo; Dal Negro, Luca

    2015-10-01

    In this paper, using the rigorous Surface Integral Equation (SIE) method, we study light scattering by Au nano-helices with geometrical dimensions comparable to the wavelength of visible light and we demonstrate that they behave as highly directional nano-antennas with largely controllable radiation and polarization characteristics in the optical regime. In particular, we systematically investigate the radiation properties of helical nano-antennas with realistic Au dispersion parameters in the visible spectral range, and we establish general design rules that enable the engineering of directional scattering with elliptical or circular polarization. Given the realistic material and geometric parameters used in this work, our findings provide novel opportunities for the engineering of chiral sensors, filters, and components for nano-scale antennas with unprecedented beam forming and polarization capabilities.

  18. Neutron radiation shielding properties of polymer incorporated self compacting concrete mixes.

    Science.gov (United States)

    Malkapur, Santhosh M; Divakar, L; Narasimhan, Mattur C; Karkera, Narayana B; Goverdhan, P; Sathian, V; Prasad, N K

    2017-07-01

    In this work, the neutron radiation shielding characteristics of a class of novel polymer-incorporated self-compacting concrete (PISCC) mixes are evaluated. Pulverized high density polyethylene (HDPE) material was used, at three different reference volumes, as a partial replacement to river sand in conventional concrete mixes. By such partial replacement of sand with polymer, additional hydrogen contents are incorporated in these concrete mixes and their effect on the neutron radiation shielding properties are studied. It has been observed from the initial set of experiments that there is a definite trend of reductions in the neutron flux and dose transmission factor values in these PISCC mixes vis-à-vis ordinary concrete mix. Also, the fact that quite similar enhanced shielding results are recorded even when reprocessed HDPE material is used in lieu of the virgin HDPE attracts further attention. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Preparation and physical properties of enhanced radiation induced crosslinking of ethylene-vinyl alcohol copolymer (EVOH)

    Energy Technology Data Exchange (ETDEWEB)

    Deng Pengyang [Changchun Institute of Applied chemistry, Chinese Academy of Science, 5625 Renmin Street, Changchun, Jilin 130022 (China) and Graduate School of Chinese Academy of Science, 19 Yuquan Street, Beijing 100039 (China)]. E-mail: dpyang@ciac.jl.cn; Liu Meihua [Changchun Institute of Applied chemistry, Chinese Academy of Science, 5625 Renmin Street, Changchun, Jilin 130022 (China); Department of Materials Science and Engineering, Jilin University, 142 Renmin Street, Changchun, Jilin 130025 (China); Zhang Wanxi [Department of Materials Science and Engineering, Jilin University, 142 Renmin Street, Changchun, Jilin 130025 (China); Sun Jiazhen [Changchun Institute of Applied chemistry, Chinese Academy of Science, 5625 Renmin Street, Changchun, Jilin 130022 (China)

    2007-05-15

    Preparation and physical properties of ethylene-vinyl alcohol copolymer (EVOH) crosslinked by enhanced radiation have been studied through various methods. It was found that the most effective agent for irradiation-crosslinking was triallyl isocyanurate (TAIC) among four kinds of polyfunctional monomers. Gel content (65.6%) was formed for EVOH-44 (content of ethylene is 44 mol%) at 200 kGy with 5% TAIC, but for EVOH-32 (content of ethylene is 32 mol%), only 37.4% gel content was formed under the same conditions. This result showed that the more the content of ethylene units comprised in EVOH, the easier the chemical bonds could be formed between different molecular chains. Tensile strength and elastic modulus increased after crosslinking at high test temperature and elongation at break decreased at the same time. Hygroscopicity of EVOH showed noticeable decrease after enhancement radiation-crosslinking.

  20. Cherenkov radiation from the target with predetermined dielectric properties, produced by a 3D-printer

    Science.gov (United States)

    Naumenko, G.; Potylitsyn, A.; Bleko, V.; Soboleva, V.; Stuchebrov, S.

    2017-07-01

    Most targets made of industrial materials, used for the generation of Cherenkov radiation (ChR) have a refractive index n > 1.4 in millimeter wavelength region. It is often a problem to get out the radiation from such cylindrical or flat targets because the angle of incidence of ChR on the outer surface of target is greater than the angle of total internal reflection. In this work we present the solution of this problem by the usage of the targets with predetermined dielectric properties, manufactured using 3-D printer. We demonstrate the emission of ChR in millimeter wavelength region from the such flat target with the refractive index n = 1.37 . Suggested technique allows us to fabricate targets with turned refractive index.

  1. On Fundamental Properties Of The Classical Electromagnetic Zero-point Radiation And Its Implications

    CERN Document Server

    Matsuoka, Y

    2005-01-01

    There is a classical theory that can explain various quantum phenomena including the Casimir effect, the van der Waals force, the blackbody radiation, and so forth [1]. The classical theory is called “stochastic electrodynamics (SED)” and only the difference from conventional classical physics is the choice of the boundary condition for Maxwell equations. It requires random electromagnetic radiation called “zero-point field (ZPF),” which exists throughout space even at zero temperature. Thus, the ZPF is thought to be an universal background field which corresponds to the vacuum ground state in the language of quantum electrodynamics. In this paper, the fundamental properties, especially the symmetries, of the ZPF are studied at first. It is found that the requirement of the Lorentz invariance of the field might be incompatible with the formulation of classical electrodynamics. Secondly, the behavior of unrestricted charged particle immersed in the ZPF is considered. Unl...

  2. Graphene coated subwavelength wires: a theoretical investigation of emission and radiation properties

    Science.gov (United States)

    Cuevas, Mauro

    2017-10-01

    This work analyzes the emission and radiation properties of a single optical emitter embedded in a graphene-coated subwavelength wire. We discuss the modifications of the spontaneous emission rate and the radiation efficiency as a function of the position and orientation of the dipole inside the wire. Our results show that these quantities can be enhanced by several orders of magnitude when the emission frequency coincides with one of the resonance frequencies of the graphene-coated wire. In particular, high-order plasmon resonances are excited when the emitter is moved from the wire center. Modifications resulting from varying the orientation of the dipole in the near field distribution and in the far field intensities are shown.

  3. Modeling of particle radiative properties in coal combustion depending on burnout

    Science.gov (United States)

    Gronarz, Tim; Habermehl, Martin; Kneer, Reinhold

    2016-08-01

    In the present study, absorption and scattering efficiencies as well as the scattering phase function of a cloud of coal particles are described as function of the particle combustion progress. Mie theory for coated particles is applied as mathematical model. The scattering and absorption properties are determined by several parameters: size distribution, spectral distribution of incident radiation and spectral index of refraction of the particles. A study to determine the influence of each parameter is performed, finding that the largest effect is due to the refractive index, followed by the effect of size distribution. The influence of the incident radiation profile is negligible. As a part of this study, the possibility of applying a constant index of refraction is investigated. Finally, scattering and absorption efficiencies as well as the phase function are presented as a function of burnout with the presented model and the results are discussed.

  4. Modeling of particle radiative properties in coal combustion depending on burnout

    Science.gov (United States)

    Gronarz, Tim; Habermehl, Martin; Kneer, Reinhold

    2017-04-01

    In the present study, absorption and scattering efficiencies as well as the scattering phase function of a cloud of coal particles are described as function of the particle combustion progress. Mie theory for coated particles is applied as mathematical model. The scattering and absorption properties are determined by several parameters: size distribution, spectral distribution of incident radiation and spectral index of refraction of the particles. A study to determine the influence of each parameter is performed, finding that the largest effect is due to the refractive index, followed by the effect of size distribution. The influence of the incident radiation profile is negligible. As a part of this study, the possibility of applying a constant index of refraction is investigated. Finally, scattering and absorption efficiencies as well as the phase function are presented as a function of burnout with the presented model and the results are discussed.

  5. Influence of ionizing radiation on the mechanical properties of BisGMA/TEGDMA based experimental resin

    Science.gov (United States)

    LMP, Campos; Boaro, LC; LKG, Santos; Parra, DF; Lugão, AB

    2015-10-01

    Dental restorative composites are activated by visible light and the polymerization process, known as direct technique, is initiated by absorbing light in a specific wavelength range (450-500 nm). However this technique presented some disadvantages. If light is not inserted correctly, layers uncured can cause countless damage to restoration, especially with regard to mechanical properties. A clinical alternative used to reduce the shortcomings of direct application is the use of composite resins for indirect application. These composites are adaptations of resins prepared for direct use, with differences mainly in the healing process. Besides the traditional photoactivation, indirect application composites may be submitted to particular curing conditions, such as a slow curing rate, heating, vacuum, and inert-gas pressure leading to an oxygen-free environment. However few studies have been conducted on the process of post-curing by ionizing radiation at low doses. On this sense the purpose of this study was to evaluate possible interactions of ionizing radiation in the post-curing process of the experimental composites based on BisGMA/TEGDMA filled with silica Aerosil OX-50 silanized. Characterization of the experimental composites was performed by thermogravimetry analysis, infrared spectroscopy, elastic modulus and flexural strength. Statistical analysis of results was calculated by one-way ANOVA/Tukey's test. Cross-linking of the polymeric matrix caused by ionizing radiation, influenced the thermal stability of irradiated specimens. FTIR analysis showed that the ionizing radiation induced a post-cure reaction in the specimens. The irradiation dose influenced directly the mechanical properties that showed a strong positive correlation between flexural strength and irradiation and between modulus strength and irradiation.

  6. Radiative properties of argon-helium-nitrogen-carbon-cobalt-nickel plasmas used in CNT synthesis

    Science.gov (United States)

    Salem, D.; Hannachi, R.; Cressault, Y.; Teulet, Ph; Béji, L.

    2015-02-01

    This work presents the radiative properties of argon-helium-nitrogen-carbon-nickel-cobalt thermal plasmas by the computation of net emission coefficients (NECs) under the assumption of a local thermodynamic equilibrium and at temperature range 1000-20 000 K. These mixtures were often used in the study of carbon nanotubes (CNTs) synthesis with arc plasma which becomes one of the most useful techniques in terms of flexibility of carbon nanostructures produced with fewer defects. The values of NEC allow estimation of total radiation losses in plasmas, by taking into account the emission radiation resulting from the atomic continuum, the molecular continuum, the atomic lines and some molecular bands. Free-free transitions (Bremsstrahlung) and free-bound (electron-ion recombination), have been considered for the calculation of atomic continuum. For bound-bound transitions, natural, resonance, Van der Waals, Stark and Doppler effects have been taken into account in the calculation of the lines broadenings while the self-absorption of the resonance lines has been treated using their escape factors. Molecular continuum has been only considered for N2, C2 and CN molecules whereas we have only taken into account diatomic systems N2, \\text{N}2+ , CN and C2 for the emission of the molecular bands. The results obtained show that even for low concentrations of Ni and Co in the plasma, the NECs are modified and considerably increase only at a low temperature (T < 8000 K) and the major contribution in the total radiation arises from the lines emission. However, the effect of the thickness of the plasma on plasma radiation has been analysed based on the self absorption phenomenon of resonance lines.

  7. Radiation damage and luminescence properties of gamma aluminum oxynitride transparent ceramic

    Science.gov (United States)

    Du, Xinhua; Yao, Shiyue; Jin, Xihai; Chen, Haohong; Li, Weifeng; Liang, Bo

    2015-09-01

    This paper reports on the radiation damage of gamma aluminum oxynitride (γ-AlON) transparent ceramic, which remarkably degrades UV-vis transparency and hence limits its applications in optoelectronic devices. The radiation-induced optical absorption of the as-sintered γ-AlON consists of at least two subbands: one is in the UV region with a peak at 270 nm and the other optical absorption band centers at 550 nm, covering the whole visible light spectrum, which makes the sample colored. Interestingly, all the radiation-induced color centers can be completely ‘bleached’ by low temperature annealing. In the thermoluminescence curve, we observed a broad luminescence in the range of 25-300 °C with the peak at 120 °C. Furthermore, the x-ray excited luminescence spectra revealed that there exist multiple emission centers in the γ-AlON. Based on this experimental fact, the radiation damage and luminescent mechanisms were studied. These optical properties of the γ-AlON are considered to be related to defect states. In the as-sintered γ-AlON, charge balancing is realized by the co-existence of \\text{V}\\text{Al}\\prime\\prime \\prime and \\text{O}\\text{N}\\bullet , and the predominant defect form is ≤ft[\\text{V}\\text{Al}\\prime\\prime \\prime-\\text{3O}\\text{N}\\bullet\\right] , which is optically inactive and no optical absorption occurs. However, isolated \\text{V}\\text{Al}\\prime\\prime \\prime and \\text{O}\\text{N}\\bullet can be formed by irradiation and it is these that are responsible for the radiation damage of γ-AlON transparent ceramic. In the end, the UV absorption and visible-light absorption in the irradiated sample were ascribed to VAl-related and ON-related intrinsic defects, respectively.

  8. Assessment of the Radiation Attenuation Properties of Several Lead Free Composites by Monte Carlo Simulation

    Directory of Open Access Journals (Sweden)

    Kazempour M.

    2015-06-01

    Full Text Available Background: In diagnostic radiology lead apron, are usually used to protect patients and radiology staff against ionizing radiation. Lead apron is a desirable shield due to high absorption and effective attenuation of x-ray photons in the diagnostic radiology range. Objective: Although lead aprons have good radiation protection properties, in recent years, researchers have been looking for alternative materials to be used instead of lead apron because of some problems derived from lead-content of aprons. Because of its lead-content, these radiation protection garments are so heavy and uncomfortable for the staff to wear, particularly in long-time uses. In addition, lead is a toxic element and its disposal is associated with environmental and human-health hazards. Method: In this study, several new combinations of lead free materials ((W-Si, (W-Sn-Ba-EPVC , (W-Sn-Cd-EPVC have been investigated in the energy range of diagnostic radiology in two geometries: narrow and broad beam. Geometries of the radiation attenuation characteristics of these materials was assessed in 40, 60, 90 and 120 kVp and the results compared with those of some lead-containing materials ((Pb-Si, (Pb-EPVC. Results: Lead shields still provide better protection in low energies (below 40 kVp. Combination of W-Sn-Cd-EPVC has shown the best radiation attenuation features in 60 and 90 kVp and the composition of (W-Sn-Ba-EPVC represents the best attenuation in 120 kVp, even better than previously mentioned lead- containing composites. Conclusion: Lead free shields are completely effective for protection against X-ray energies in the range of 60 to 120 kVp.

  9. Effect of low-intensity electromagnetic radiation on structurization properties of bacterial lipopolysaccharide

    Directory of Open Access Journals (Sweden)

    Grigory E. Brill

    2014-09-01

    Full Text Available Purpose — to investigate the effects of low-intensity electromagnetic radiation on the process of dehydration selforganization of bacterial lipopolysaccharide (LPS. Material and Methods — The method of wedge dehydration has been used to study the structure formation of bacterial LPS. Image-phases analysis included their qualitative characteristics, as well as the calculation of quantitative indicators, followed by statistical analysis. Results — Low-intensity ultra high frequency (UHF radiation (1 GHz, 0.1 μW/cm2, 10 min has led to the changes in the suspension system of the LPS-saline reflected in the kinetics of structure formation. Conclusion — 1 GHz corresponds to the natural frequency of oscillation of water clusters and, presumably, the effect of UHF on structure of LPS mediates through the changes in water-salt environment. Under these conditions, properties of water molecules of hydration and possibly the properties of hydrophobic and hydrophilic regions in the molecule of LPS, which can affect the ability of toxin molecules to form aggregates change. Therefore the LPS structure modification may result in the change of its toxic properties.

  10. Effect of low-intensity electromagnetic radiation on structurization properties of bacterial lipopolysaccharide

    Directory of Open Access Journals (Sweden)

    Brill G.E.

    2013-12-01

    Full Text Available Purpose: to investigate the effects of low-intensity electromagnetic radiation on the process of dehydration self-organization of bacterial lipopolysaccharide. Materials and Methods. The method of wedge dehydration has been used to study the structure formation of bacterial lipopolysaccharide. Image-phases analysis included their qualitative characteristics, as well as the calculation of quantitative indicators, followed by statistical analysis. Results. UHF-Radiation (1GHz, 0,1 uW/cm2, 10 min has led to the changes in the suspension system of the LPS-saline reflected in the kinetics of structure formation. Conclusion. 1 GHz corresponds to the natural frequency of oscillation of water clusters and, presumably, the effect of UHF on structure of LPS mediates through the changes in water-salt environment. Under these conditions, properties of water molecules of hydration and possibly the properties of hydrophobic and hydrophilic regions in the molecule of LPS, which can affect the ability of toxin molecules to form aggregates change. Therefore the lipopolysaccharide structure modification may result in the change of its toxic properties.

  11. Measuring the radiative properties of astrophysical matter using the Z X-ray source

    Science.gov (United States)

    Bailey, James; ZAPP Team

    2017-06-01

    The Z Astrophysical Plasma Properties (ZAPP) collaboration is staging Z experiments that simultaneously investigate multiple topics in radiative properties of hot dense matter. The four astrophysics questions presently guiding this research are: 1) Why can’t we predict the location of the convection zone base in the Sun?; 2) How does radiation transport affect spectrum formation in accretion-powered objects?; 3) Why doesn’t spectral fitting provide the correct properties for White Dwarfs?; and 4) Why can’t we predict the heating and charge state distribution in photoionized plasmas? Recent progress using Z, the most energetic x-ray source on earth, to address these questions will be described. We emphasize the first two topics. Opacity models are an essential ingredient of stellar models and are highly sophisticated, but laboratory opacity tests have only now become possible at the conditions existing inside stars. Our opacity research emphasizes measuring iron at conditions relevant to the base of the solar convection zone, where the electron temperature and density are believed to be 190 eV and 9x1022 e/cc, respectively. The results exhibit large disagreements between iron opacity measurements and models and ongoing research is aimed at testing hypotheses for this discrepancy. The second project is motivated by the fact that emission lines from L-shell ions are not observed from iron in black hole accretion disks, but are observed from silicon in x-ray binaries. These disparate observations may be explained by differences in the radiation transport within the plasmas, but models for the spectral line formation and transport in photoionized plasmas have never been tested. We investigate photoionized silicon plasmas using absorption spectroscopy to infer the plasma conditions and emission spectroscopy to determine the dependence of spectral emission on plasma column density.++Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed

  12. Preparation and properties of hydrogels of PVA/PVP/chitosan by radiation

    Energy Technology Data Exchange (ETDEWEB)

    Nho, Y. C.; Park, K. R. [KAERI, Taejon (Korea, Republic of)

    2001-05-01

    The radiation can induce chemical reaction to modify polymer under even the solid condition or in the low temperature. The radiation crosslinking can be easily adjusted and is easily reproducible by controlling the radiation dose. The finished product contains no residuals of substances required to initiate the chemical crosslinking which can restrict the application possibilities. In these studies, hydrogels from a mixture of chitosan and polyvinyl alcohol(PVA)/Poly-N-vinylpyrrolidone(PVP) were made by 'freezing and thawing', or gamma-ray irradiation or two steps of 'freezing and thawing', and gamma-ray irradiation or two steps of 'freezing and thawing' and gamma-ray irradiation for wound dressing. The mechanical properties such as gelation, water absorptivity, and gel strength were examined to evaluate the hydrogels for wound dressing. The composition of PVA:PVP was 60:40, PVA/PVP: chitosan ratio was in the range of 9:1 -7:3, and the solid concentration of PVA/PVP/chitosan solution was 15wt%. Gamma irradiation doses of 25, 35, 50, 60 and 70kGy, respectively were exposed to a mixture of PVA/PVP/chitosan to evaluate the effect of irradiation dose on the mechanical properties of hydrogels. Water-soluble chitosan was used to in this experiment. The mechanical properties of hydrogels such as gelation and gel strength was higher when two steps of 'freezing and thawing' and irradiation were used than only 'freezing and thawing' was utilized. Gel content was influenced slightly by PVA/PVP:chitosan composition and irradiation dose, but swelling was done greatly by them. Swelling percent was much increased as the composition of chitosan in PVA/PVP/chitosan increased.

  13. Aerosol optical, microphysical and radiative properties at regional background insular sites in the western Mediterranean

    Science.gov (United States)

    Sicard, Michaël; Barragan, Rubén; Dulac, François; Alados-Arboledas, Lucas; Mallet, Marc

    2016-09-01

    In the framework of the ChArMEx (the Chemistry-Aerosol Mediterranean Experiment; http://charmex.lsce.ipsl.fr/) program, the seasonal variability of the aerosol optical, microphysical and radiative properties derived from AERONET (Aerosol Robotic Network; http://aeronet.gsfc.nasa.gov/) is examined in two regional background insular sites in the western Mediterranean Basin: Ersa (Corsica Island, France) and Palma de Mallorca (Mallorca Island, Spain). A third site, Alborán (Alborán Island, Spain), with only a few months of data is considered for examining possible northeast-southwest (NE-SW) gradients of the aforementioned aerosol properties. The AERONET dataset is exclusively composed of level 2.0 inversion products available during the 5-year period 2011-2015. AERONET solar radiative fluxes are compared with ground- and satellite-based flux measurements. To the best of our knowledge this is the first time that AERONET fluxes are compared with measurements at the top of the atmosphere. Strong events (with an aerosol optical depth at 440 nm greater than 0.4) of long-range transport aerosols, one of the main drivers of the observed annual cycles and NE-SW gradients, are (1) mineral dust outbreaks predominant in spring and summer in the north and in summer in the south and (2) European pollution episodes predominant in autumn. A NE-SW gradient exists in the western Mediterranean Basin for the aerosol optical depth and especially its coarse-mode fraction, which all together produces a similar gradient for the aerosol direct radiative forcing. The aerosol fine mode is rather homogeneously distributed. Absorption properties are quite variable because of the many and different sources of anthropogenic particles in and around the western Mediterranean Basin: North African and European urban areas, the Iberian and Italian peninsulas, most forest fires and ship emissions. As a result, the aerosol direct forcing efficiency, more dependent to absorption than the absolute

  14. Radiation shielding properties of a novel cement–basalt mixture for nuclear energy applications

    Energy Technology Data Exchange (ETDEWEB)

    Ipbüker, Cagatay; Nulk, Helena; Gulik, Volodymyr [University of Tartu, Institute of Physics (Estonia); Biland, Alex [HHK Technologies, Houston (United States); Tkaczyk, Alan Henry, E-mail: alan@ut.ee [University of Tartu, Institute of Physics (Estonia)

    2015-04-01

    Highlights: • Basalt fiber is a relatively cheap material that can be used as reinforcement. • Gamma-ray attenuation remains relatively stable with addition of basalt fiber. • Neutron attenuation remains relatively stable with addition of basalt fiber. • Cement–basalt mixture has a good potential for use in nuclear energy applications. - Abstract: The radiation shielding properties of a new proposed building material, a novel cement–basalt fiber mixture (CBM), are investigated. The authors analyze the possibility of this material to be a viable substitute to outgoing materials in nuclear energy applications, which will lead to a further sustained development of nuclear energy in the future. This computational study involves four types of concrete with various amounts of basalt fiber in them. The gamma-ray shielding characteristics of proposed CBM material are investigated with the help of WinXCom program, whereas the neutron shielding characteristics are computed by the Serpent code. For gamma-ray shielding, we find that the attenuation coefficients of concretes with basalt fibers are not notably influenced by the addition of fibers. For neutron shielding, additional basalt fiber in mixture presents negligible effect on neutron radiation shielding. With respect to radiation shielding, it can be concluded that basalt fibers have good potential as an addition to heavyweight concrete for nuclear energy applications.

  15. Spectroscopic analysis of radiation-generated changes in tensile properties of a polyetherimide film

    Science.gov (United States)

    Long, E. R., Jr.; Long, S. A. T.

    1985-01-01

    The effects of electron radiation on Ultem, a polyetherimide were studied for doses from 2 x 10 to the 9th power to 6 x 10 to the 9th power rad. Specimens were studied for tensile property testing and for electron paramagnetic resonance and infrared spectroscopic measurements of molecular structure. A Faraday cup design and a method for remote temperature measurement were developed. The spectroscopic data show that radiation caused dehydrogenation of methyl groups, rupture of main-chain ether linkage, and opening of imide rings, all to form radicals and indicate that the so-formed atomic hydrogen attached to phenyl radicals, but not to phenoxyl radicals, which would have formed hydroxyls. The observed decays of the radiation-generated phenoxyl, gem-dimethyl, and carbonyl radicals were interpreted as a combining of the radicals to form crosslinking. This crosslinking is the probable cause of the major reduction in the elongation of the tensile specimens after irradiation. Subsequent classical solubility tests indicate that the irradiation caused massive crosslinking.

  16. Effect of gamma radiation and endodontic treatment on mechanical properties of human and bovine root dentin

    Energy Technology Data Exchange (ETDEWEB)

    Novais, Veridiana Resende; Soares, Priscilla Barbosa Ferreira; Guimaraes, Carlla Martins; Schliebe, Lais Rani Sales Oliveira; Braga, Stella Sueli Lourenco; Soares, Carlos Jose, E-mail: carlosjsoares@ufu.br [Universidade Federal de Uberlandia (UFU), MG (Brazil)

    2016-11-15

    This study evaluated the effect of gamma radiation and endodontic treatment on the microhardness and flexural strength of human and bovine root dentin. Forty single rooted human teeth and forty bovine incisor teeth were collected, cleaned and stored in distilled water at 4 °C. The human and bovine teeth were divided into 4 groups (n=10) resulting from the combination of two study factors: first, regarding the endodontic treatment in 2 levels: with or without endodontic treatment; and second, radiotherapy in two levels: with or without radiotherapy by 60 Gy of Co-60 gamma radiation fractioned into 2 Gy daily doses five days per week. Each tooth was longitudinally sectioned in two parts; one-half was used for the three-point bending test and the other for the Knoop hardness test (KHN). Data were analyzed by 3-way ANOVA and Tukey HSD test (α=0.05). No significant difference was found for flexural strength values. The human dentin had significantly higher KHN than the bovine. The endodontic treatment and radiotherapy resulted in significantly lower KHN irrespective of tooth origin. The results indicated that the radiotherapy had deleterious effects on the microhardness of human and bovine dentin and this effect is increased by the interaction with endodontic therapy. The endodontic treatment adds additional negative effect on the mechanical properties of radiated tooth dentin; the restorative protocols should be designed taking into account this effect. (author)

  17. Radiative properties of magnetic neutron stars with metallic surfaces and thin atmospheres

    CERN Document Server

    Potekhin, A Y; van Adelsberg, M; Werner, K

    2012-01-01

    The goal of this work is to develop a simple analytic description of the emission properties (spectrum and polarization) of the condensed, strongly magnetized surface of neutron stars. We have improved the method of van Adelsberg et al. (2005) (arXiv:astro-ph/0406001) for calculating the spectral properties of condensed magnetized surfaces. Using the improved method, we calculate the reflectivity of an iron surface at magnetic field strengths B \\sim (10^{12} - 10^{14}) G, with various inclinations of the magnetic field lines and radiation beam with respect to the surface and each other. We construct analytic expressions for the emissivity of this surface as functions of the photon energy, magnetic field strength, and the three angles that determine the geometry of the local problem. Using these expressions, we calculate X-ray spectra for neutron stars with condensed iron surfaces covered by thin partially ionized hydrogen atmospheres. We develop simple analytic descriptions of the intensity and polarization o...

  18. Crosslinking of rigid PVC by ionizing radiation to improve its thermal properties

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Castaneda, C. [Centro de Investigacion en Quimica Aplicada, Blvd. Enrique Reyna 140, Saltillo Coahuila (Mexico); Benavides, R., E-mail: robertob@ciqa.m [Centro de Investigacion en Quimica Aplicada, Blvd. Enrique Reyna 140, Saltillo Coahuila (Mexico); Martinez-Pardo, M.E. [Instituto Nacional de Investigaciones Nucleares, Apartado postal 18-1027, Col. Escandon, 11801 Mexico, D.F. (Mexico); Uribe, R.M. [Kent State University, College of Technology and Program on Electron Beam Technology, P.O. Box 5190, Kent, OH 44242-0001 (United States); Carrasco-Abrego, H. [Instituto Nacional de Investigaciones Nucleares, Apartado postal 18-1027, Col. Escandon, 11801 Mexico, D.F. (Mexico); Martinez, G. [Centro de Investigacion en Quimica Aplicada, Blvd. Enrique Reyna 140, Saltillo Coahuila (Mexico)

    2010-03-15

    Rigid PVC formulations containing two different stabilizer systems (tin and Ca/Zn) and TMPTMA as a crosslinking agent were treated with ionizing radiation (gamma and electron beam) at different doses and irradiation atmospheres. The objective was to increase thermal and mechanical properties of this material. Polyene formation was followed through the yellowing index (YI), the extent of crosslinking by gel percentage, thermal resistance by Vicat temperature and the mechanical properties by DMA. Both formulations became colored with irradiation, especially with gamma as a result of a longer treatment time; the gel formation and the Vicat temperature were also higher for gamma treated samples, suggesting that values were enhanced by oxidation. However, DMA elastic modulus traces were almost similar for both treatments. The main difference observed for Ca/Zn samples compared with traditional tin samples was the lower ability of the former system in protecting the material against processing conditions.

  19. Parameterization of sea-salt optical properties and physics of the associated radiative forcing

    Directory of Open Access Journals (Sweden)

    J. Li

    2008-03-01

    Full Text Available The optical properties of sea-salt aerosol have been parameterized at solar and longwave wavelengths. The optical properties were parameterized in a simple functional form in terms of the ambient relative humidity based on Mie optical property calculations. The proposed parameterization is tested relative to Mie calculations and is found to be accurate to within a few percent. In the parameterization, the effects of the size distribution on the optical properties are accounted for in terms of effective radius of the sea-salt size distribution. This parameterization differs from previous works by being formulated directly with the wet sea-salt size distribution (and compared to AERONET results and, to our knowledge, this is the first published sea-salt parameterization to provide a parameterization for both solar and longwave wavelengths. We have used this parameterization in a set of idealized 1-D radiative transfer calculations to investigate the sensitivity of various attributes of sea-salt forcing, such as dependence with sea-salt column loading, effective variance, solar angle, and surface albedo. From these sensitivity tests, it is found that sea-salt forcings for both solar and longwave spectra are linearly related to the sea-salt loading for realistic values of loadings. The radiative forcing results illustrate that the shortwave forcing is an order of magnitude greater than the longwave forcing results and opposite in sign, for various loadings. Studies of the sensitivity of forcing results to variations in effective variance show there to be minimal variation; therefore, only one value of effective variance is used in the parameterization. The dependence of sea-salt forcing with solar angle illustrates an interesting result that sea-salt can generate a positive top-of-the-atmosphere result (i.ewarming when the solar zenith angle is relatively small 30° Finally, it is found that the surface albedo significantly affects the solar

  20. On the radiative and thermodynamic properties of the Cosmic Microwave Background radiation using COBE FIRAS instrument data

    CERN Document Server

    Fisenko, Anatoliy I

    2014-01-01

    Use formulas to describe the monopole and dipole spectra of the Cosmic Microwave Background (CMB) radiation, the exact expressions for the temperature dependences of the radiative and thermodynamic functions, such as the total radiation power per unit area, total energy density, number density of photons, Helmholtz free energy density, entropy density, heat capacity at constant volume, pressure, enthalpy density, and internal energy density in the finite range of frequencies are obtained. Since the dependence of temperature upon the redshift z is known, the obtained expressions can be simply presented in z representation. Utilizing experimental data for the monopole and dipole spectra measured by the COBE FIRAS instrument in the 60 - 600 GHz frequency interval at the temperature T = 2.728 K, the values of the radiative and thermodynamic functions, as well as the radiation density constant a and the Stefan-Boltzmann constant are calculated. In the case of the dipole spectrum, the constants a and the Stefan-Bol...

  1. The multispectral reflectance of shortwave radiation by agricultural crops in relation with their morphological and optical properties

    NARCIS (Netherlands)

    Bunnik, N.J.J.

    1978-01-01

    Relations between morphological properties of uniform canopies. optical properties of the leaves and reflection of shortwave radiation, in the visible light region and the near infrared, by crops are the subject of this thesis.The aim of the study was a further investigation of potential application

  2. UHMW-PE. A shielding material with special properties influenced by radiation

    Energy Technology Data Exchange (ETDEWEB)

    Ehe, K. von der; Jaunich, M.; Wolff, D. [Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin (Germany)

    2011-07-01

    Ultra high molecular weight polyethylene (UHMW-PE) - due to its high hydrogen content - is used as neutron shielding material in casks for storage and transport of radioactive materials. Besides this, UHMW-PE - as a high-performance polymer - has been used for several years in medical technology due to its excellent slip and wear properties. Due to the special properties of UHMW-PE which result basically from its extreme chain lengths and its high degree of crystallinity, it is predestinated for the aforementioned applications. In both cases, irradiation and its impact on the molecular structure of polyethylene play an important role. In the first case, irradiation exists as a by-product of inserting the radioactive material in the cask. Hence PE has to withstand any type of degradation affecting safety relevant aspects to be applicable for long term radiation shielding purposes for instance over a period of 40 years. In the second case irradiation is applied deliberately for purposes such as sterilization and crosslinking, leading to partial improvement of the mechanical properties (e.g. fracture toughness, crack propagation resistance, wear resistance) and better chemical stability. Specifically concerning their use in the field of medical technology, different types of UHMW-PE have been objects of numerous publications. It is generally accepted that two parallel and competitive processes, based on chain scission and reactions of C-centered radicals and molecular fragments, occur in PE as a consequence of radiation: radical recombination accounts for crosslinking, together with some disproportionation, formation of low molecular weight fragments, and recrystallization. Furthermore, formation of oxygenated structures in the presence of traces of oxygen is an antagonist of the C-centered radicals. Radiation induced scission preferentially takes place in the amorphous phase and noncrystalline surface of the crystals. It is followed by folding of molecular fragments

  3. Dielectric and Radiative Properties of Sea Foam at Microwave Frequencies: Conceptual Understanding of Foam Emissivity

    Directory of Open Access Journals (Sweden)

    Peter W. Gaiser

    2012-04-01

    Full Text Available Foam fraction can be retrieved from space-based microwave radiometric data at frequencies from 1 to 37 GHz. The retrievals require modeling of ocean surface emissivity fully covered with sea foam. To model foam emissivity well, knowledge of foam properties, both mechanical and dielectric, is necessary because these control the radiative processes in foam. We present a physical description of foam dielectric properties obtained from the foam dielectric constant including foam skin depth; foam impedance; wavelength variations in foam thickness, roughness of foam layer interfaces with air and seawater; and foam scattering parameters such as size parameter, and refraction index. Using these, we analyze the scattering, absorption, reflection and transmission in foam and gain insights into why volume scattering in foam is weak; why the main absorption losses are confined to the wet portion of the foam; how the foam impedance matching provides the transmission of electromagnetic radiation in foam and maximizes the absorption; and what is the potential for surface scattering at the foam layers boundaries. We put all these elements together and offer a conceptual understanding for the high, black-body-like emissivity of foam floating on the sea surface. We also consider possible scattering regimes in foam.

  4. Transverse coherence properties of X-ray beams in third-generation synchrotron radiation sources

    CERN Document Server

    Geloni, Gianluca; Schneidmiller, Evgeni; Yurkov, Mikhail

    2008-01-01

    This article describes a complete theory of spatial coherence for undulator radiation sources. Current estimations of coherence properties often assume that undulator sources are quasi-homogeneous, like thermal sources, and rely on the application of the van Cittert-Zernike theorem for calculating the degree of transverse coherence. Such assumption is not adequate when treating third generation light sources, because the vertical(geometrical) emittance of the electron beam is comparable or even much smaller than the radiation wavelength in a very wide spectral interval that spans over four orders of magnitude (from 0.1 Angstrom up to 10^3 Angstrom). Sometimes, the so-called Gaussian-Schell model, that is widely used in statistical optics in the description of partially-coherent sources, is applied as an alternative to the quasi-homogeneous model. However, as we will demonstrate, this model fails to properly describe coherent properties of X-ray beams from non-homogeneous undulator sources. As a result, a more...

  5. Resistivity, ESR, and Radiation Shielding Properties of the Volcanic Rock Materials

    Directory of Open Access Journals (Sweden)

    Çiğdem Nuhoğlu

    2014-01-01

    Full Text Available Pumices have been used in cement, concrete, brick, and ceramic industries as an additive and aggregate material. It will be important to study pumice types by using a different tool as EPR which is a new technique for related material to be used for industrial aims. Electron spin resonance (ESR spectra of the pumice types were taken by EMX-type spectrometer. Also, the current-voltage (I-V and surface resistivity probe stand of the thin films was studied using a four-point probe measurements. The relationship between radiation shielding properties of the pumice samples and their surface resistivity, chemical, and electrokinetic properties was evaluated using simple regression analysis. Simple regression analysis indicated a strong correlation between surface resistivity and density and SiO2, Fe2O3, CaO, MgO, and TiO2 content of pumice samples in this study. It is found that a correlation between determined g-factor by EPR spectroscopy and radiation shielding is established for pumice samples.

  6. CHANGE IN DEFORMATION PROPERTIES MODELING OF CONCRETE IN PROTECTIVE STRUCTURES OF NUCLEAR REACTOR BY IONIZING RADIATION

    Directory of Open Access Journals (Sweden)

    E. K. Agakhanov

    2016-01-01

    Full Text Available The necessity of studying the effect impact of elementary particles impact on the strength and deformation materials properties used in protective constructions nuclear reactors and reactor technology has been stipulated. A nuclear reactor pressure vessel from prestressed concrete, combining the functions of biological protection is to be considered. The neutron flux problem distribution in the pressure vessel of a nuclear reactor has been solved. The solution is made in axisymmetric with the finite element method using a flat triangular finite element. Computing has been conducted in Matlab package. The comparison with the results has been obtained using the finite difference method, as well as the graphs of changes under the influence of radiation exposure and the elastic modulus of concrete radiation deformations have been constructed. The proposed method allows to simulate changes in the deformation properties of concrete under the influence of neutron irradiation. Results of the study can be used in the calculation of stress-strain state of structures, taking into account indirect heterogeneity caused by the physical fields influence.

  7. Effects of UVB Radiation on the Physicochemical Properties of Fibroblasts and Keratinocytes.

    Science.gov (United States)

    Dobrzyńska, Izabela; Szachowicz-Petelska, Barbara; Skrzydlewska, Elżbieta; Figaszewski, Zbigniew A

    2016-06-01

    The skin is the largest human organ, providing the first line of defense to protect the body from physical and environmental effects. The aim of this study was to determine the influence of short-wave ultraviolet (UVB) radiation on the membrane electrical properties, phospholipid content, and lipid peroxidation levels of fibroblasts and keratinocytes. Changes in cell function may affect the basal electrical surface properties of cell membranes. These changes can be detected using electrokinetic measurements. In this study, the surface charge densities of fibroblasts and keratinocytes were measured as a function of pH. A four-component equilibrium model was used to describe the interaction between the ions in solution and on cell membrane surfaces. Agreement was found between the experimental and theoretical charge variation curves of leukemia cells from pH 2.5 to pH 9. Phospholipid composition was determined qualitatively and quantitatively by HPLC, and lipid peroxidation was estimated by measuring the level of malondialdehyde. The acidic functional group concentrations and average association constants with hydroxyl ions were higher, and the average association constants with hydrogen ions were smaller in UVB-treated skin cell membranes compared to those in untreated cells. Moreover, our results showed that UVB radiation is associated with increased levels of phospholipids and lipid peroxidation products in fibroblasts and keratinocytes.

  8. Effect of penetrating ionising radiation on the mechanical properties of pericardium

    Energy Technology Data Exchange (ETDEWEB)

    Daar, Eman, E-mail: e.daar@surrey.ac.u [Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom); Woods, E. [Royal Free Hampstead NHS Trust, Pond Street, Hampstead, London NW3 2QG (United Kingdom); Keddie, J.L. [Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom); Nisbet, A. [Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom); Royal Surrey County Hospital, Guildford (United Kingdom); Bradley, D.A. [Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom)

    2010-07-21

    The pericardium is an anistropic composite material made up of collagen and elastin fibres embedded in an amorphous matrix mainly composed of proteoglycan and hyaluronan. The collagen fibres are arranged in layers, with different directions of alignment in each layer, giving rise to interesting mechanical properties of pericardium, including the ability to undergo large deformation during performance of regular physiological functions. The present study aims to investigate the effect of penetrating photon ionising radiation on bovine pericardium tissue, being part of a study of the effect of cardiac doses received in breast radiotherapy and the possibility that this can give rise to cardiovascular complications. Irradiation doses in the range 5-80 Gy were used. To characterise the various mechanical properties [elastic modulus, stress relaxation, ultimate tensile strength (UTS) and fracture] a uniaxial tensile test method was applied. The preliminary results reflect the wide inter-sample variations that are expected in dealing with tissues, with only a weak indication of increase in the UTS of the pericardium tissue with increase in radiation dose. Such an effect has also been observed by others, with reduction in UTS at doses of 80 Gy.

  9. Effect of magnetic polaritons on the radiative properties of inclined plate arrays

    Science.gov (United States)

    Wang, Liping; Haider, Ahmad; Zhang, Zhuomin

    2014-01-01

    This study investigates the spectral radiative properties of inclined parallel-plate arrays with emphasis on the effect of magnetic polaritons. The rigorous coupled-wave analysis (RCWA) is employed and the geometry of parallel-plate arrays is reproduced by considering the structure as a multilayered grating with lateral shift. Enhanced absorption at specific wavelengths with angular independence due to the excitation of magnetic resonances is demonstrated with the numerical calculation. The magnetic resonance condition can be simply predicted by a modified capacitor-inductor (LC) model, and electromagnetic field distributions are presented to illustrate the unique behavior of magnetic polaritons such as field localization and induced currents. The agreement between the RCWA and LC model on the resonance conditions confirms the excitation of magnetic polaritons. A parametric study is conducted to investigate the geometric effects on the radiative properties. It is shown that the resonance wavelengths of magnetic polaritons can be tuned by changing the plate length, thickness, period, or inclination angle. The understanding gained from this study may benefit the design of energy harvesting devices.

  10. Gamma radiation influences pasting, thermal and structural properties of corn starch

    Science.gov (United States)

    Ben Bettaïeb, Nasreddine; Jerbi, Mohamed Taïeb; Ghorbel, Dorra

    2014-10-01

    Irradiation is one of the effective methods able to change starch structure and its functional properties. In this research, the effect of γ-radiation (3, 5, 10, 20 and 50 kGy) on the pasting, thermal, structural and morphological properties of corn starch was studied. Brabender viscoamylograph test showed that the maximal consistency of the starch paste and its corresponding temperature decreased significantly with increasing irradiation dose. Differential scanning calorimetry also showed a decrease in gelatinization temperatures (TOnset, Tp, TOffset) with increasing irradiation dose. Fourier transform infrared spectroscopy spectra showed that the irradiated starch displayed a significant decrease in the intensity of O-H stretch, C-H stretch, bending mode of water and bending mode of glycosidic linkage. No modification in the shape and intensity of X-ray diffraction peaks was observed after irradiation. These results suggested that until 50 kGy, γ- radiation would affect the starch granule membrane and the amorphous zone rather than the crystalline one.

  11. Effect of radiation on disinfection and mechanical properties of Korean traditional paper, Hanji

    Science.gov (United States)

    Choi, Jong-il; Chung, Yong Jae; Kang, Dai Ill; Lee, Kyu Shik; Lee, Ju-Woon

    2012-08-01

    Fumigants, including methyl bromide and ethylene oxide, are generally used for the preservation of the Korean cultural heritage, especially paper products like letters and books. However, the use of fumigants is banned because of their harmful effects on humans and the environment. Gamma irradiation is being considered as an alternative for the sterilization of insects and fungi in organic products. Therefore, the purpose of this study was to investigate the sterilization effects of radiation and its effect on the mechanical properties of the Korean traditional paper—Hanji. Treatment doses of 9 kGy and 8 kGy of gamma irradiation inactivated 5 log units of Aspergillus niger and Bacillus cereus spores inoculated on Hanji, respectively. The gamma irradiations up to an absorbed dose of 50 kGy resulted in no significant changes in the tensile strength, bursting strength, and appearance of Hanji. These results confirmed that radiation treatment disinfects the Korean traditional paper efficiently without changing its properties and that this treatment could be used to prevent the damage of Korean ancient archives by molds and fungi.

  12. Effect of UV radiation as an alternative to thermal pasteurization on some properties of tomato juice

    Directory of Open Access Journals (Sweden)

    Mahsa Noktehsanj-Avval

    2016-06-01

    Full Text Available Most foods are usually pasteurizedby thermal processes. Pasteurization can reduce organoleptic and nutritional characteristics of the products. Radiation isa new technique for reduction of food poisoning due to food consumption and increasing shelf life of the product. In the present study, the effect of UV radiation as a cold pasteurization was investigated on the quality of tomato juice (TJ to improve sensory, chemical and microbial properties. Treatments T1, T2, T3, T4, were tomato juice with heat treatment (treatment temperature 60 °C- 2 min as a control treatment, pasteurized samples (treatments 72 °C for 2min, irradiated samples (from 15cm- 30min, and irradiated samples (15cm- 60minute, respectively. T3 and T4 samples received radiation dose of 2.158 j/m2. The prepared samples were stored at a refrigerator for 90 days and every 30 days, the chemical test (lycopene content, pH, acidity, vitamin C, and Brix, were performed. The results showed that pH has significantly increased (p ˂ 0.05 in all four treatments during storage. Generally the effects of irradiation on the Brix were not significant (p ˂ 0.05. By increasing irradiation time, amounts of lycopene significantly increased (p ˂ 0.05, also decreases were observed in both treatments T3 and T4 during storage. Radiation compared to the thermal treatment was successful in retaining and increasing the amount of vitamin C, which was significantly increase in T4 treatment (p ˂ 0/05, in first day. pH were reduced during storage in all samples.

  13. Synergetic radar and lidar algorithm for the retrieval of radiative and microphysical properties in ice clouds

    Science.gov (United States)

    Tinel, Claire; Testud, Jacques; Protat, Alain; Pelon, Jacques R.

    2003-04-01

    To appreciate the radiative impact of clouds in the dynamics of the global atmosphere, it is important to deploy from space, from aircraft, or from ground, instruments able to describe the cloud layering and to document the cloud characteristics (namely liquid and/or ice water content, and the effective particle radius). In the framework of EarthCARE (ESA), that plans to associate a cloud radar and a lidar on the same spatial platform, RALI (RAdar-LIdar) airborne system is an interesting demonstrator. RALI combines the 95 GHz radar of the CETP and the 0.5 μm wavelength backscattering lidar of the SA. In order to derive the radiative and microphysical properties of clouds, a synergetic algorithm has been developed. It combines the apparent backscatter coefficient, βa, from the lidar and the apparent reflectivity, Za, from the radar to infer properties of the particle size distribution. The principle of this algorithm is to apply in parallel the Hitschfeld-Bordan algorithm to the radar and the Klett algorithm to the lidar. Taken separately, these two algorithms are unstable, but by considering a mutual constraint, it is shown that a stable solution can be established. This solution formulates the retrieval of the true reflectivity and backscattering coefficient, to access microphysical and radiative parameters of clouds. This algorithm allows also to retrieve the variable N0* parameter, which is a normalization parameter of the particle size distribution. This synergetic algorithm has been tested with simulated cases, and results of the algorithm applied on real data are validated by microphysical in-situ measurements.

  14. Sensitivity of radiative properties of persistent contrails to the ice water path

    Directory of Open Access Journals (Sweden)

    R. Rodríguez De León

    2011-07-01

    Full Text Available The dependence of the radiative properties of persistent linear contrails on the variability of their ice water path is assessed in a two-stream radiative transfer model. It is assumed that the ice water content and the effective size of ice crystals in aged contrails do not differ from those observed in natural cirrus; the parameterization of these two variables, based on in situ observations, allows a more realistic representation than the common assumption of fixed values for the contrail optical depth and ice crystal effective radius.

    The results show that the large variability in ice water content that aged contrails may share with natural cirrus, together with an assumed contrail vertical thickness between 220 and 1000 m, translate into a wider range of radiative forcings from linear contrails (0.3 to 51.6 mW m−2 than that reported in previous studies, including IPCC's (3 to 30 mW m−2. The derivation of a best estimate within this range is complicated by the fact that the ice water contents measured in situ imply mean optical depths between 0.08 and 0.32, coinciding with the range commonly assumed in contrail studies, while optical depths derived from satellite ice water content retrievals are significantly larger (0.51–2.02. Further field and modelling studies of the temporal evolution of contrail properties will thus be needed to reduce the uncertainties associated with the values assumed in large scale contrail studies.

  15. Magnetic Properties Studies on Thermal Aged Fe-Cu Alloys for the Simulation of Radiation Damage

    Energy Technology Data Exchange (ETDEWEB)

    Lee, C. K.; Kishore, M.B.; Park, D. G. [KAERI, Daejeon (Korea, Republic of); Son, De Rac. [Hannam University, Daejeon (Korea, Republic of)

    2016-05-15

    We evaluated the changes in magnetic properties due to cold rolling and thermal ageing of a Fe-1%Cu model alloy in this study. Initially, the alloy was 10% cold rolled, and isothermally aged at 400 .deg. C for 1, 10, 100 and 1000 hr. The samples were prepared at various thermal aging conditions and all the conditions were interpreted. The hysteresis loops, Magnetic Barkhausen noise (BN). The change of magnetic properties can be interpreted in terms of the domain wall motion and dislocation dynamics associated with copper rich precipitates (CRPs).The results were interpreted in terms of ageing time dependence of the precipitates evolution such as the volume fraction and size distribution. In order to evaluate the radiation embrittlement of RPV steel, A Cold rolled Fe-Cu model Alloy was prepared, The prepared samples were thermally aged by annealing at 400 .deg. C for various times, the magnetic properties of the annealed samples were measured, The Barkhausen noise and BH Loop shows a considerable trend corresponding to the Ageing time. The magnetic properties were interpreted and correlated to the CRPs formed through annealing process.

  16. Radiative Effect of Clouds on Tropospheric Chemistry: Sensitivity to Cloud Vertical Distributions and Optical Properties

    Science.gov (United States)

    Liu, H.; Crawford, J. H.; Pierce, R. B.; Considine, D. B.; Logan, J. A.; Duncan, B. N.; Norris, P.; Platnick, S. E.; Chen, G.; Yantosca, R. M.; Evans, M. J.

    2005-12-01

    Representation of clouds in global models poses a significant challenge since most cloud processes occur on sub-grid scales and must be parameterized. Uncertainties in cloud distributions and optical properties are therefore a limiting factor in model assessments of the radiative effect of clouds on global tropospheric chemistry. We present an analysis of the sensitivity of the radiative effect of clouds to cloud vertical distributions and optical properties with the use of the GEOS-CHEM global 3-D chemistry transport model coupled with the Fast-J radiative transfer algorithm. GEOS-CHEM was driven with a series of meteorological archives (GEOS1-STRAT, GEOS-3, and GEOS-4) generated by the Goddard Earth Observing System data assimilation system (GEOS DAS) at the NASA global Modeling and Assimilation Office (GMAO), which have significantly different cloud optical depths and vertical distributions. The column cloud optical depths in GEOS-3 generally agree with the satellite retrieval products from the Moderate Resolution Imaging Spectroradiometer (MODIS) and the International Satellite Cloud Climatology Project (ISCCP) within ±10%, while those in GEOS1-STRAT and GEOS-4 are too low by factors of about 5 and 2, respectively. With respect to vertical distribution, clouds in GEOS-4 are optically much thinner in the tropical upper troposphere compared to those in GEOS1-STRAT and GEOS-3. Assuming linear scaling of cloud optical depth with cloud fraction in a grid-box, our model calculations indicate that the changes in global mean hydroxyl radical (OH) due to the radiative effect of clouds in June are about -1% (GEOS1-STRAT), 1% (GEOS-3), and 14% (GEOS-4), respectively. The effects on global mean OH are similar for GEOS1-STRAT and GEOS-3 due to similar vertical distributions of clouds, even though the column cloud optical depths in the two archives differ by a factor of about 5. Clouds in GEOS-4 have a much larger impact on global mean OH because more solar radiation is

  17. Optical and radiative properties of aerosols over Abu Dhabi in the United Arab Emirates

    Science.gov (United States)

    Beegum, S. Naseema; Romdhane, Haifa Ben; Ali, Mohammed Tauha; Armstrong, Peter; Ghedira, Hosni

    2016-12-01

    The present study is on the aerosol optical and radiative properties in the short-wave radiation and its climate implications at the arid city of Abu Dhabi (24.42 ∘N, 54.61 ∘E, 4.5 m MSL), in the United Arab Emirates. The direct aerosol radiative forcings (ARF) in the short-wave region at the top (TOA) and bottom of the atmosphere (BOA) are estimated using a hybrid approach, making use of discrete ordinate radiative transfer method in conjunction with the short-wave flux and spectral aerosol optical depth (AOD) measurements, over a period of 3 years (June 2012-July 2015), at Abu Dhabi located at the south-west coast of the Arabian Gulf. The inferred microphysical properties of aerosols at the measurement site indicate strong seasonal variations from the dominance of coarse mode mineral dust aerosols during spring (March-May) and summer (June-September), to the abundance of fine/accumulation mode aerosols mainly from combustion of fossil-fuel and bio-fuel during autumn (October-November) and winter (December-February) seasons. The monthly mean diurnally averaged ARF at the BOA (TOA) varies from -13.2 Wm-2 (˜-0.96 Wm-2) in November to -39.4 Wm-2 (-11.4 Wm-2) in August with higher magnitudes of the forcing values during spring/summer seasons and lower values during autumn/winter seasons. The atmospheric aerosol forcing varies from + 12.2 Wm-2 (November) to 28.2 Wm-2 (June) with higher values throughout the spring and summer seasons, suggesting the importance of mineral dust aerosols towards the solar dimming. Seasonally, highest values of the forcing efficiency at the surface are observed in spring (-85.0 ± 4.1 W m-2 τ -1) followed closely by winter (-79.2 ± 7.1 W m-2 τ -1) and the lowest values during autumn season (-54 ± 4.3 W m-2 τ -1). The study concludes with the variations of the atmospheric heating rates induced by the forcing. Highest heating rate is observed in June (0.39 K day -1) and the lowest in November (0.17 K day -1) and the temporal

  18. Optical and radiative properties of aerosols over Abu Dhabi in the United Arab Emirates

    Indian Academy of Sciences (India)

    S Naseema Beegum; Haifa Ben Romdhane; Mohammed Tauha Ali; Peter Armstrong; Hosni Ghedira

    2016-12-01

    The present study is on the aerosol optical and radiative properties in the short-wave radiation and its climate implications at the arid city of Abu Dhabi (24.42°N, 54.61°E, 4.5 m MSL), in the United Arab Emirates. The direct aerosol radiative forcings (ARF) in the short-wave region at the top (TOA) and bottom of the atmosphere (BOA) are estimated using a hybrid approach, making use of discrete ordinate radiative transfer method in conjunction with the short-wave flux and spectral aerosol optical depth (AOD) measurements, over a period of 3 years (June 2012–July 2015), at Abu Dhabi located at the southwest coast of the Arabian Gulf. The inferred microphysical properties of aerosols at the measurementsite indicate strong seasonal variations from the dominance of coarse mode mineral dust aerosols during spring (March–May) and summer (June–September), to the abundance of fine/accumulation modeaerosols mainly from combustion of fossil-fuel and bio-fuel during autumn (October–November) and winter(December–February) seasons. The monthly mean diurnally averaged ARF at the BOA (TOA) varies from −13.2Wm⁻² (∼ −0.96 Wm⁻²) in November to −39.4 Wm⁻² (−11.4 Wm⁻²) in August with higher magnitudes of the forcing values during spring/summer seasons and lower values during autumn/winter seasons. The atmospheric aerosol forcing varies from +12.2 Wm⁻² (November) to 28.2 Wm⁻² (June) with higher values throughout the spring and summer seasons, suggesting the importance of mineral dust aerosols towards the solar dimming. Seasonally, highest values of the forcing efficiency at the surfaceare observed in spring (−85.0± 4.1Wm⁻²τ⁻¹) followed closely by winter (−79.2±7.1 W m⁻²τ⁻¹) and the lowest values during autumn season (−54±4.3W m⁻²τ⁻¹). The study concludes with the variations of the atmospheric heating rates induced by the forcing. Highest heating rate is observed in June (0.39 K day⁻¹) and the lowest in November

  19. Climatological and radiative properties of midlatitude cirrus clouds derived by automatic evaluation of lidar measurements

    Science.gov (United States)

    Kienast-Sjögren, Erika; Rolf, Christian; Seifert, Patric; Krieger, Ulrich K.; Luo, Bei P.; Krämer, Martina; Peter, Thomas

    2016-06-01

    Cirrus, i.e., high, thin clouds that are fully glaciated, play an important role in the Earth's radiation budget as they interact with both long- and shortwave radiation and affect the water vapor budget of the upper troposphere and stratosphere. Here, we present a climatology of midlatitude cirrus clouds measured with the same type of ground-based lidar at three midlatitude research stations: at the Swiss high alpine Jungfraujoch station (3580 m a.s.l.), in Zürich (Switzerland, 510 m a.s.l.), and in Jülich (Germany, 100 m a.s.l.). The analysis is based on 13 000 h of measurements from 2010 to 2014. To automatically evaluate this extensive data set, we have developed the Fast LIdar Cirrus Algorithm (FLICA), which combines a pixel-based cloud-detection scheme with the classic lidar evaluation techniques. We find mean cirrus optical depths of 0.12 on Jungfraujoch and of 0.14 and 0.17 in Zürich and Jülich, respectively. Above Jungfraujoch, subvisible cirrus clouds (τ change in cloud morphology at Jungfraujoch above ˜ 13 km, possibly because high particle number densities form in the observed cirrus clouds, when many ice crystals nucleate in the high supersaturations following rapid uplifts in lee waves above mountainous terrain. The retrieved optical properties are used as input for a radiative transfer model to estimate the net cloud radiative forcing, CRFNET, for the analyzed cirrus clouds. All cirrus detected here have a positive CRFNET. This confirms that these thin, high cirrus have a warming effect on the Earth's climate, whereas cooling clouds typically have cloud edges too low in altitude to satisfy the FLICA criterion of temperatures below -38 °C. We find CRFNET = 0.9 W m-2 for Jungfraujoch and 1.0 W m-2 (1.7 W m-2) for Zürich (Jülich). Further, we calculate that subvisible cirrus (τ < 0.03) contribute about 5 %, thin cirrus (0.03 < τ < 0.3) about 45 %, and opaque cirrus (0.3 < τ) about 50 % of the total cirrus radiative forcing.

  20. Study of material properties important for an optical property modulation-based radiation detection method for positron emission tomography.

    Science.gov (United States)

    Tao, Li; Daghighian, Henry M; Levin, Craig S

    2017-01-01

    We compare the performance of two detector materials, cadmium telluride (CdTe) and bismuth silicon oxide (BSO), for optical property modulation-based radiation detection method for positron emission tomography (PET), which is a potential new direction to dramatically improve the annihilation photon pair coincidence time resolution. We have shown that the induced current flow in the detector crystal resulting from ionizing radiation determines the strength of optical modulation signal. A larger resistivity is favorable for reducing the dark current (noise) in the detector crystal, and thus the higher resistivity BSO crystal has a lower (50% lower on average) noise level than CdTe. The CdTe and BSO crystals can achieve the same sensitivity under laser diode illumination at the same crystal bias voltage condition while the BSO crystal is not as sensitive to 511-keV photons as the CdTe crystal under the same crystal bias voltage. The amplitude of the modulation signal induced by 511-keV photons in BSO crystal is around 30% of that induced in CdTe crystal under the same bias condition. In addition, we have found that the optical modulation strength increases linearly with crystal bias voltage before saturation. The modulation signal with CdTe tends to saturate at bias voltages higher than 1500 V due to its lower resistivity (thus larger dark current) while the modulation signal strength with BSO still increases after 3500 V. Further increasing the bias voltage for BSO could potentially further enhance the modulation strength and thus, the sensitivity.

  1. Impacts and implementation of fuel moisture release and radiation properties in modelling of pulverized fuel combustion processes

    DEFF Research Database (Denmark)

    Yin, Chungen

    2015-01-01

    Pulverized fuels (PF) prepared and fired in utility boilers usually contain a certain amount of moisture, either free moisture or chemically bound moisture. In PF furnaces, radiation which is the principal mode of heat transfer consists of contribution from both gas and particle phase. This paper...... presents different methods for fuel moisture release and new models for gas and particle radiative properties, and demonstrates their implementation, importance and impacts in PF combustion modelling via a comprehensive CFD study of a pulverized coal-fired utility boiler. To conclude, it is recommended...... to add the free moisture into the primary air stream while lump the moisture retained in the feed after the mills with volatiles in PF combustion modelling. For gas and particle radiation in PF boilers, it is found that particle radiation largely overwhelms gas radiation due to high particle loading...

  2. Influence of CO2 Laser Radiation on the Mechanical Properties of Portland Cement Pastes

    Directory of Open Access Journals (Sweden)

    González-Mota, R.

    2011-03-01

    Full Text Available This article presents the results of the treatment of fresh cement pastes with CO2 laser radiation (10.6μm, in order to improve its mechanical properties in addition to obtaining lower setting times than those of a natural setting (without radiation . It was observed that the CO2 laser radiation has a positive influence on the mechanical properties of cement paste, not due to the heat produced during irradiation, but due to the effect of electric field propagation on water molecules, whose are arranged around functional groups of the binder and by the effect of ration, causes a micro vibration effect, resulting in a more compact and less porous paste which has better mechanical properties compared to natural setting paste. The internal and surface temperature of the samples, the evolution of setting, Young's modulus (using ultrasonic pulse velocity and compressive strength were registered.En este artículo se presentan los resultados correspondientes al tratamiento de pastas frescas de cemento con radiación láser de CO2 (10.6µm, con el propósito de mejorar sus propiedades mecánicas además de obtener tiempos de fraguado menores a los del fraguado en forma natural (sin radiación. Se demostró que la radiación con láser de CO2 influye positivamente en las propiedades mecánicas de la pasta de cemento, no por el calentamiento producido durante la irradiación, sino por el efecto de la propagación del campo eléctrico sobre las moléculas de agua que están dispuestas alrededor de los grupos funcionales del aglutinante y que al rotar producen un efecto equivalente a micro vibraciones, dando como resultado un material más compacto, con menos poros y mejores propiedades mecánicas respecto al fraguado natural. Se registró la temperatura interna y superficial de las muestras, la evolución del fraguado, el módulo de Young y la resistencia a compresión.

  3. Microscopic properties of xenon plasmas for density and temperature regimes of laboratory astrophysics experiments on radiative shocks.

    Science.gov (United States)

    Rodríguez, R; Espinosa, G; Gil, J M; Stehlé, C; Suzuki-Vidal, F; Rubiano, J G; Martel, P; Mínguez, E

    2015-05-01

    This work is divided into two parts. In the first one, a study of radiative properties (such as monochromatic and the Rosseland and Planck mean opacities, monochromatic emissivities, and radiative power loss) and of the average ionization and charge state distribution of xenon plasmas in a range of plasma conditions of interest in laboratory astrophysics and extreme ultraviolet lithography is performed. We have made a particular emphasis in the analysis of the validity of the assumption of local thermodynamic equilibrium and the influence of the atomic description in the calculation of the radiative properties. Using the results obtained in this study, in the second part of the work we have analyzed a radiative shock that propagated in xenon generated in an experiment carried out at the Prague Asterix Laser System. In particular, we have addressed the effect of plasma self-absorption in the radiative precursor, the influence of the radiation emitted from the shocked shell and the plasma self-emission in the radiative precursor, the cooling time in the cooling layer, and the possibility of thermal instabilities in the postshock region.

  4. Thermal and mechanical properties of blends of LDPE and EVA crosslinked by electron beam radiation

    Science.gov (United States)

    Borhani Zarandi, Mahmoud; Amrollahi Bioki, Hojjat

    2013-08-01

    Low density polyethylene (LDPE) blends with different percentages of ethylene vinyl acetate (EVA) irradiated with 10 MeV electron beam in the range of 50-250 kGy at room temperature. The effect of irradiation and EVA content on the mechanical and thermal properties of LDPE was studied. It was revealed that for all blends increasing the applied dose up to 150 kGy would result in decrease in the specific heat capacity (cp) and thermal conductivity (k) of LDPE and then raised slightly with further increased in radiation doses. The gel content showed that under the irradiation, the crosslinking density at each irradiation dose depends almost on the amorphous portions of the LDPE/EVA. The mechanical properties of LDPE/EVA blends were found to be influenced by the electron beam irradiation and EVA content. It can be deduced that the mechanical properties of LDPE are improved by blending with EVA and irradiated by electron beam. Fourier transform infrared (FTIR) spectroscopy was used to characterize the structure of LDPE. Result indicates small variation in crystalline content, which could be increased or decreased on the formation of important bond groups.

  5. Rediscovering leaf optical properties: New insights into plant acclimation to solar UV radiation.

    Science.gov (United States)

    Barnes, Paul W; Flint, Stephan D; Ryel, Ronald J; Tobler, Mark A; Barkley, Anne E; Wargent, Jason J

    2015-08-01

    The accumulation of UV-absorbing compounds (flavonoids and other phenylpropanoid derivatives) and resultant decrease in the UV transmittance of the epidermis in leaves (TUV), is a primary protective mechanism against the potentially deleterious effects of UV radiation and is a critical component of the overall acclimation response of plants to changing UV environments. Traditional measurements of TUV were laborious, time-consuming and destructive or invasive, thus limiting their ability to efficiently make multiple measurements of the optical properties of plants in the field. The development of rapid, nondestructive optical methods of determining TUV has permitted the examination of UV optical properties of leaves with increased replication, on a finer time scale, and enabled repeated sampling of the same leaf over time. This technology has therefore allowed for studies examining acclimation responses to UV in plants in ways not previously possible. Here we provide a brief review of these earlier studies examining leaf UV optical properties and some of their important contributions, describe the principles by which the newer non-invasive measurements of epidermal UV transmittance are made, and highlight several case studies that reveal how this technique is providing new insights into this UV acclimation response in plants, which is far more plastic and dynamic than previously thought.

  6. Thin film AlSb carrier transport properties and room temperature radiation response

    Science.gov (United States)

    Vaughan, Erin Ivey

    Theoretical predictions for AlSb material properties have not been realized using bulk growth methods. This research was motivated by advances in molecular beam epitaxial (MBE) growth technology to produce high-quality thin-film AlSb for the purpose of evaluating transport properties and suitability for radiation detection. Simulations using MCNP5 were performed to benchmark an existing silicon surface barrier detector and to predict ideal AlSb detector behavior, with the finding that AlSb should have improved detection efficiency due to the larger atomic number of Sb compared with Si. GaSb diodes were fabricated by both homoepitaxial MBE and ion implantation methods in order to determine the effect on the radiation detection performance. It was found that the radiation response for the MBE grown GaSb diodes was very uniform, whereas the ion-implanted GaSb diodes exhibited highly variable spectral behavior. Two sets of AlSb heterostructures were fabricated by MBE methods; one for a Hall doping study and the other for a radiation response study. The samples were characterized for material quality using transmission electron microscopy (TEM), Nomarski imaging, atomic force microscopy (AFM), x-ray diffraction (XRD), I-V curve analysis, and Hall effect measurements. The Hall study samples were grown on semi-insulating (SI) GaAs substrates and contained a thin GaAs layer on top to protect the AlSb from oxygen. Doping for the AlSb layer was achieved using GaTe and Be for n- and p-type conductivity, respectively, with intended doping densities ranging from 1015 to 1017 cm -3. Results for net carrier concentration ranged 2x10 9 to 1x1017 cm-3, 60 to 3000 cm 2/Vs for mobility, and 2 to 106 Ω-cm for resistivity, with the undoped AlSb samples presenting the best values. The radiation detector samples were designed to be PIN diodes, with undoped AlSb sandwiched between n-type GaAs substrate and p-type GaSb as a conductive oxygen-protective layer. Energy spectra were measured

  7. Study of surface properties of ATLAS12 strip sensors and their radiation resistance

    Science.gov (United States)

    Mikestikova, M.; Allport, P. P.; Baca, M.; Broughton, J.; Chisholm, A.; Nikolopoulos, K.; Pyatt, S.; Thomas, J. P.; Wilson, J. A.; Kierstead, J.; Kuczewski, P.; Lynn, D.; Hommels, L. B. A.; Ullan, M.; Bloch, I.; Gregor, I. M.; Tackmann, K.; Hauser, M.; Jakobs, K.; Kuehn, S.; Mahboubi, K.; Mori, R.; Parzefall, U.; Clark, A.; Ferrere, D.; Sevilla, S. Gonzalez; Ashby, J.; Blue, A.; Bates, R.; Buttar, C.; Doherty, F.; McMullen, T.; McEwan, F.; O'Shea, V.; Kamada, S.; Yamamura, K.; Ikegami, Y.; Nakamura, K.; Takubo, Y.; Unno, Y.; Takashima, R.; Chilingarov, A.; Fox, H.; Affolder, A. A.; Casse, G.; Dervan, P.; Forshaw, D.; Greenall, A.; Wonsak, S.; Wormald, M.; Cindro, V.; Kramberger, G.; Mandić, I.; Mikuž, M.; Gorelov, I.; Hoeferkamp, M.; Palni, P.; Seidel, S.; Taylor, A.; Toms, K.; Wang, R.; Hessey, N. P.; Valencic, N.; Hanagaki, K.; Dolezal, Z.; Kodys, P.; Bohm, J.; Stastny, J.; Bevan, A.; Beck, G.; Milke, C.; Domingo, M.; Fadeyev, V.; Galloway, Z.; Hibbard-Lubow, D.; Liang, Z.; Sadrozinski, H. F.-W.; Seiden, A.; To, K.; French, R.; Hodgson, P.; Marin-Reyes, H.; Parker, K.; Jinnouchi, O.; Hara, K.; Sato, K.; Hagihara, M.; Iwabuchi, S.; Bernabeu, J.; Civera, J. V.; Garcia, C.; Lacasta, C.; Marti i Garcia, S.; Rodriguez, D.; Santoyo, D.; Solaz, C.; Soldevila, U.

    2016-09-01

    A radiation hard n+-in-p micro-strip sensor for the use in the Upgrade of the strip tracker of the ATLAS experiment at the High Luminosity Large Hadron Collider (HL-LHC) has been developed by the "ATLAS ITk Strip Sensor collaboration" and produced by Hamamatsu Photonics. Surface properties of different types of end-cap and barrel miniature sensors of the latest sensor design ATLAS12 have been studied before and after irradiation. The tested barrel sensors vary in "punch-through protection" (PTP) structure, and the end-cap sensors, whose stereo-strips differ in fan geometry, in strip pitch and in edge strip ganging options. Sensors have been irradiated with proton fluences of up to 1×1016 neq/cm2, by reactor neutron fluence of 1×1015 neq/cm2 and by gamma rays from 60Co up to dose of 1 MGy. The main goal of the present study is to characterize the leakage current for micro-discharge breakdown voltage estimation, the inter-strip resistance and capacitance, the bias resistance and the effectiveness of PTP structures as a function of bias voltage and fluence. It has been verified that the ATLAS12 sensors have high breakdown voltage well above the operational voltage which implies that different geometries of sensors do not influence their stability. The inter-strip isolation is a strong function of irradiation fluence, however the sensor performance is acceptable in the expected range for HL-LHC. New gated PTP structure exhibits low PTP onset voltage and sharp cut-off of effective resistance even at the highest tested radiation fluence. The inter-strip capacitance complies with the technical specification required before irradiation and no radiation-induced degradation was observed. A summary of ATLAS12 sensors tests is presented including a comparison of results from different irradiation sites. The measured characteristics are compared with the previous prototype of the sensor design, ATLAS07.

  8. Seasonal variation of columnar aerosol optical properties and radiative forcing over Beijing, China

    Science.gov (United States)

    Yu, Xingna; Lü, Rui; Liu, Chao; Yuan, Liang; Shao, Yixing; Zhu, Bin; Lei, Lu

    2017-10-01

    Long-term seasonal characteristics of aerosol optical properties and radiative forcing at Beijing (during March 2001-March 2015) were investigated using a combination of ground-based Sun/sky radiometer retrievals from the AERONET and a radiative transfer model. Aerosol optical depth (AOD) showed a distinct seasonal variation with higher values in spring and summer, and relatively lower values in fall and winter. Average Angstrom exponent (AE) in spring was lower than other seasons, implying the significant impact of dust episodes on aerosol size distribution. AE mainly distributed between 1.0 and 1.4 with an obvious uni-peak pattern in each season. The observation data showed that high AODs (>1.0) were clustered in the fine mode growth wing and the coarse mode. Compared to AOD, seasonal variation in single scattering albedo (SSA) showed an opposite pattern with larger values in summer and spring, and smaller ones in winter and fall. The highest volume size distribution and median radius of fine mode particles occurred in summer, while those of coarse mode particles in spring. The averaged aerosol radiative forcing (ARF) at the top of the atmosphere (TOA) in spring, summer, fall and winter were -33 ± 22 W m-2, -35 ± 22 W m-2, -28 ± 20 W m-2, and -24 ± 23 W m-2 respectively, and these differences were mainly due to the SSA seasonal variation. The largest positive ARF within atmosphere occurred in spring, implying strong warming in the atmosphere. The low heating ratio in summer was caused by the increase in water vapor content, which enhanced light scattering capacity (i.e., increased SSA).

  9. Investigation the optical and radiative properties of aerosol vertical profile of boundary layer by lidar and ground based measurements

    Science.gov (United States)

    Chen, W.; Chou, C.; Lin, P.; Wang, S.

    2011-12-01

    The planetary boundary layer is the air layer near the ground directly affected by diurnal heat, moisture, aerosol, and cloud transfer to or from the surface. In the daytime solar radiation heats the surface, initiating thermal instability or convection. Whereas, the scattering and absorption of aerosols or clouds might decrease the surface radiation or heat atmosphere which induce feedbacks such as the enhanced stratification and change in relative humidity in the boundary layer. This study is aimed to understand the possible radiative effect of aerosols basing on ground based aerosol measurements and lidar installed in National Taiwan University in Taipei. The optical and radiative properties of aerosols are dominated by aerosol composition, particle size, hygroscopicity property, and shape. In this study, aerosol instruments including integrating nephelometer, open air nephelometer, aethalometer are applied to investigate the relationship between aerosol hygroscopicity properties and aerosol types. The aerosol hygroscopicity properties are further applied to investigate the effect of relative humidity on aerosol vertical profiles measured by a dual-wavelength and depolarization lidar. The possible radiative effect of aerosols are approached by vertical atmospheric extinction profiles measured by lidar. Calculated atmospheric and aerosol heating effects was compared with vertical meteorological parameters measured by radiosonde. The result shows light-absorbing aerosol has the potential to affect the stability of planetary boundary layer.

  10. Effects of ionizing radiation on the physicochemical properties of red wine Cabernet Sauvignon

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Fellipe S.; Santos, Anderson R.L.; Pereira, Walsan W., E-mail: fellipess@ird.gov.br, E-mail: aleiras@ird.gov.br, E-mail: walsan@ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2015-07-01

    Oenology has as its main purpose the continuous improvement of wine quality without jeopardizing its proprieties, and the intent is to make these improvements using innovative new technologies. The objective of the present work is to assess the effect of ionizing radiation on the physicochemical properties of Cabernet Sauvignon that may lead to changes in wine quality, aging process and other related characteristics. The samples used for this process were irradiated using an Argonaut reactor powered at 340 Watts and with a thermal neutron fluency of 10{sup 9} n.cm{sup -2}.s{sup -1}. For irradiation experiments, the samples were put into the reactor chamber until the reactor reached criticality and for an additional 30 minutes while receiving radiation. The analyzed data included density, alcoholic, ashes and spectrophotometric measurements of absorbance at wavelengths of 420, 520 and 620 nm. Increased absorbance values at 420 nm indicate an increase in tannin composition of the wine and therefore a higher level of oxidation. Intriguingly, a rise in absorbance was also observed at 520 nm for the same test samples; which is inconsistent with published data on irradiated cachaca that showed that anthocyanin levels dropped at 520 nm after irradiation. In summary, for measurements made at a fluency of 109 n/cm{sup 2}.s for 30 min, the effects were minimal, which requires a higher dose to have better effects. Future studies should evaluating dosing effects of irradiation on improving the quality of the Cabernet Sauvignon. (author)

  11. Gamma Radiation Effects on Physical, Optical, and Structural Properties of Binary As-S glasses

    Energy Technology Data Exchange (ETDEWEB)

    Sundaram, S. K.; McCloy, John S.; Riley, Brian J.; Murphy, Mark K.; Qiao, Hong (Amy); Windisch, Charles F.; Walter, Eric D.; Crum, Jarrod V.; Golovchak, Roman; Shpotyuk, O.

    2012-03-01

    Gamma radiation induces changes in physical, optical, and structural properties in chalcogenide glasses., Previous research has focused on As{sub 2}S{sub 3} and families of glasses containing Ge. For the first time, we present composition and dose dependent data on the As-S binary glass series. Binary As{sub x}S{sub 100-x} (x = 30, 33, 36, 40, and 42) glasses were irradiated with gamma radiation using a {sup 60}Co source at 2.8 Gy/s to accumulated doses of 1, 2, 3, and 4 MGy. The irradiated samples were characterized at each dose level for density, refractive index, x-ray diffraction, and Raman spectrum. These results are compared to those of as-made and 1 year aged samples. We report an initial increase in density followed by a decrease as a function of dose that contradicts the expected compositional dependence of molar volume of these glasses. This unusual behavior is explained based on microvoid formation and nanoscale phase-separation induced by the irradiation in these glasses. XRD, Raman, and EPR data provide supporting evidence, underscoring the importance of optimally- or overly-constrained structures for stability under aging or irradiation.

  12. Evolution of structure and infrared radiation properties for ferrite-based amorphous coating

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Lei [State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081 (China); Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education, Wuhan University of Science and Technology, Wuhan 430081 (China); Fan, Xi’an, E-mail: groupfxa@163.com [State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081 (China); Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education, Wuhan University of Science and Technology, Wuhan 430081 (China); Zhang, Jianyi [State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081 (China); Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education, Wuhan University of Science and Technology, Wuhan 430081 (China); Hu, Xiaoming [Suzhou Sagreon New Materials Co., Ltd, Zhangjiagang 215625 (China); Li, Guangqiang; Zhang, Zhan [State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081 (China); Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education, Wuhan University of Science and Technology, Wuhan 430081 (China)

    2014-10-15

    Highlights: • The ferrite-based amorphous infrared radiation coating was prepared by plasma spraying. • The coating could keep amorphous structure when the temperature was below 700 °C. • The amorphous structure can improve the emissivity of ferrite-based coatings. • The amorphous coating exhibited a higher emissivity than that by brushing process. • The coating has an excellent thermal shock resistance and can work at 1000 °C. - Abstract: The ferrite-based amorphous coatings with high infrared radiation properties have been successfully prepared on the surface of carbon steel substrate by plasma spraying process. The phase, morphology, microstructure, thermal behavior and infrared emissivity were determined by X-ray diffraction, scanning electron microscopy, differential scanning calorimetry and infrared spectroscopy. The prepared coating could keep amorphous structure when the ambient temperature was below 700 °C and it would crystallize gradually with further increasing the temperature. The amorphous structure is confirmed to be constructive for improving the emissivity of ferrite-based coatings, especially in the 3–8 μm band. The emissivity of the amorphous coating obtained by plasma spraying was over 0.8 in 3–8 μm band at 800 °C, which was higher than that of the coating with same composition prepared by conventional brushing method. The excellent thermal shock resistance of the coatings makes them to be good candidates for sensible energy-saving materials, which could work for long term at 1000 °C.

  13. Retrieving ice cloud properties by using a fast infrared radiative transfer model

    Science.gov (United States)

    Wang, C.; Yang, P.; Heidinger, A. K.; Platnick, S. E.; Baum, B. A.

    2010-12-01

    A new fast infrared radiative transfer (RT) model based on pre-computed look-up tables (LUTs) including the LUTs for emissivity function and cloud effective temperature is proposed. This model can be applied to the simulation of upward radiance (or brightness temperature) at 8.5, 11.0 and 12.0 μm at the top of the atmosphere (TOA) under cloudy-sky conditions. Optical depths of Atmospheric layers resulting from gaseous absorption are derived from the correlated-K distribution (CKD) method. The cloud reflection and transmission functions are computed from the discrete ordinates radiative transfer model (DISORT). In addition to the LUTs of reflection and transmission functions of cloud in traditional RT models, the LUTs of emissivity and effective temperature are also included to improve the accuracy. Generally speaking, for an atmosphere containing a single ice cloud layer with small optical thickness (i.e., less than 5.0), the brightness temperature differences (BTDs) between the fast model and DISORT results are approximately less than 0.1K, whereas the BTDs are less than 0.02K when the ice cloud optical thickness is larger than 5.0. Moreover, with the fast RT model, cloud optical and microphysical properties of ice clouds are retrieved from MODIS and CALIPSO observations and the MERRA reanalysis data. The present retrievals are compared with the MODIS operational cloud products (MYD06).

  14. Research on Ground-Based LWIR Hyperspectral Research on Ground-Based LWIR Hyperspectral Imaging Remote Gas Detection Imaging Remote Gas Detection%地面长波红外高光谱成像气体探测研究

    Institute of Scientific and Technical Information of China (English)

    郑为建; 雷正刚; 余春超; 杨智雄; 王海洋; 付艳鹏; 李训牛; 廖宁放; 苏君红

    2016-01-01

    The new progress of ground-based long-wave infrared remote sensing is presented ,which describes the windowing spatial and temporal modulation Fourier spectroscopy imaging in details .The prototype forms the interference fringes based on the corner-cube of spatial modulation of Michelson interferometer ,using cooled long-wave infrared photovoltaic staring FPA (focal plane array) detector .The LWIR hyperspectral ima-ging is achieved by the process of collection ,reorganization ,correction ,apodization ,FFT etc .from data cube .Noise equivalent spectral radiance (NESR) ,which is the sensitivity index of CHIPED-1 LWIR hyper-spectral imaging prototype ,can reach 5.6 × 10-8 W · (cm-1 · sr · cm2 )-1 at single sampling .The data is the same as commercial temporal modulation hyperspectral imaging spectrometer .It can prove the advantage of this technique . This technique still has space to be improved . For instance , spectral response range of CHIPED-1 LWIR hyperspectral imaging prototype can reach 11.5μm by testing the transmission curve of pol-ypropylene film .In this article ,choosing the results of outdoor high-rise and diethyl ether gas experiment as an example ,the authors research on the detecting method of 2D distribution chemical gas VOC by infrared hyper-spectral imaging .There is no observed diethyl ether gas from the infrared spectral slice of the same wave num-ber in complicated background and low concentration .By doing the difference spectrum ,the authors can see the space distribution of diethyl ether gas clearly . Hyperspectral imaging is used in the field of organic gas VOC infrared detection .Relative to wide band infrared imaging ,it has some advantages .Such as ,it has high sensitivity ,the strong anti-interference ability ,identify the variety ,and so on . Abstract The new progress of ground-based long-wave infrared remote sensing is presented ,which describes the windowing spatial and temporal modulation Fourier spectroscopy imaging in details

  15. Radiation Shielding Properties Comparison of Pb-Based Silicate, Borate, and Phosphate Glass Matrices

    Directory of Open Access Journals (Sweden)

    Suwimon Ruengsri

    2014-01-01

    Full Text Available Theoretical calculations of mass attenuation coefficients, partial interactions, atomic cross-section, and effective atomic numbers of PbO-based silicate, borate, and phosphate glass systems have been investigated at 662 keV. PbO-based silicate glass has been found with the highest total mass attenuation coefficient and then phosphate and borate glasses, respectively. Compton scattering has been the dominate interaction contributed to the different total attenuation coefficients in each of the glass matrices. The silicate and phosphate glass systems are more appropriate choices as lead-based radiation shielding glass than the borate glass system. Moreover, comparison of results has shown that the glasses possess better shielding properties than standard shielding concretes, suggesting a smaller size requirement in addition to transparency in the visible region.

  16. Tailoring Thermal Radiative Properties with Film-Coupled Concave Grating Metamaterials

    CERN Document Server

    Wang, Hao

    2014-01-01

    This work numerically investigates the radiative properties of film-coupled metamaterials made of a two-dimensional metallic concave grating on a continuous metal film separated by an ultrathin dielectric spacer. Spectrally-selective absorption is demonstrated in the visible and near-infrared regime, and underlying mechanisms are elucidated to be either localized magnetic polaritons (MPs) or surface plasmon polaritons (SPPs). The unique behaviors of MPs and SPPs are explained with the help of electromagnetic field distributions at respective resonance frequencies. An inductor-capacitor model is utilized to further confirm the excitation of MP, while dispersion relation is used to understand the behaviors of different SPP modes. Geometric effects of ridge width and grating period on the resonance absorption peaks are discussed. Moreover, directional responses at oblique incidences for different polarization states are studied. Fundamental understanding gained here will facilitate the design of novel metamateri...

  17. Properties of para-terphenyl as detector for alpha, beta and gamma radiation

    CERN Document Server

    Angelone, M; Bellini, F; Bocci, V; Collamati, F; De Lucia, E; Faccini, R; Ferroni, F; Fiore, S; Marafini, M; Materazzo, D; Mattei, I; Morganti, S; Patera, V; Piersanti, L; Pillon, M; Recchia, L; Russomando, A; Sarti, A; Sciubba, A; Camillocci, E Solfaroli; Voena, C

    2013-01-01

    Organic scintillators are often chosen as radiation detectors for their fast decay time and their low Z, while inorganic ones are used when high light ields are required. In this paper we show that a para-terphenyl based detector has a blend of properties of the two categories that can be optimal for energy and position measurements of low energy charged particles. On 0.1% diphenylbutadiene doped para-terphenyl samples we measure a light yield 3.5+-0.2 times larger than a typical organic scintillator (EJ-200), and a rejection power for 660 keV photons, with respect to electrons of the same energy, ranging between 3-11%, depending on the signal threshold. We also measure a light attenuation length = 4.73+-0.06 mm and we demonstrate that, with the measurements performed in this paper, a simulation based on FLUKA can properly reproduce the measured spectra.

  18. Early radiative properties of the developments of time-symmetric conformally flat initial data

    Energy Technology Data Exchange (ETDEWEB)

    Kroon, Juan Antonio Valiente [Max Planck Institut fuer Gravitationsphysik, Albert Einstein Institut, Am Muehlenberg 1, 14476 Golm (Germany)

    2003-03-07

    Using a representation of spatial infinity based on the properties of conformal geodesics, the first terms of an expansion for the Bondi mass for the development of time-symmetric, conformally flat initial data are calculated. As is to be expected, the Bondi mass agrees with the ADM at the sets where null infinity 'touches' spatial infinity. The second term in the expansion is proportional to the sum of the squared norms of the Newman-Penrose constants of the spacetime. On the basis of this result it is argued that these constants may provide a measure of the incoming radiation contained in the spacetime. This is illustrated by means of the Misner and Brill-Lindquist datasets. (letter to the editor)

  19. Total Heat Exchange Factor Based on Non-Gray Radiation Properties of Gas in Reheating Furnace

    Institute of Scientific and Technical Information of China (English)

    CUI Miao; CHEN Hai-geng; XU Li; WU Bin

    2009-01-01

    Modified mathematical models based on imaginary plane zone method in reheating furnace were developed in which non-gray radiation properties of gas were considered,and the Newton's method and the finite difference method were adopted.Effects of productivity,fuel consumption,fuel-air ratio,calorific value of fuel and inserting depth of thermocouple on total heat exchange factor along the length of reheating furnace were investigated.The resuits show that total heat exchange factor increases with productivity or inserting depth of thermocouple,and it decreases when fuel consumption,fuel-air ratio or calorific value of fuel increases.The results are valuable for dynamical compensation of total heat exchange factor for online control mathematical models in reheating furnace.

  20. Functional properties of nisin-carbohydrate conjugates formed by radiation induced Maillard reaction

    Science.gov (United States)

    Muppalla, Shobita R.; Sonavale, Rahul; Chawla, Surinder P.; Sharma, Arun

    2012-12-01

    Nisin-carbohydrate conjugates were prepared by irradiating nisin either with glucose or dextran. Increase in browning and formation of intermediate products was observed with a concomitant decrease in free amino and reducing sugar groups indicating occurrence of the Maillard reaction catalyzed by irradiation. Nisin-carbohydrate conjugates showed a broad spectrum antibacterial activity against Gram negative bacteria (Escherichia coli, Pseudomonas fluorescence) as well as Gram positive bacteria (Staphylococcus aureus, Bacillus cereus). Results of antioxidant assays, including that of DPPH radical-scavenging activity and reducing power, showed that the nisin-dextran conjugates possessed better antioxidant potential than nisin-glucose conjugate. These results suggested that it was possible to enhance the functional properties of nisin by preparing radiation induced conjugates suitable for application in food industry.

  1. Effect of radiation and temperature on resonance properties of polyurethane-coated wire bonds

    Science.gov (United States)

    Izen, J. M.; Chen, Y.; Kurth, M.

    2017-04-01

    Thin polyurethane (PU) coatings for aluminum wedge wire bonds are proposed to protect the ATLAS Inner Tracker upgrade from oscillations from periodic Lorentz forces and condensation-induced corrosion. Coating robustness after exposure to lifetime doses expected by parts of a tracking detector at the High Luminosity-Large Hadron Collider has been evaluated. Mechanical properties of irradiated samples were tested at room temperature and at 0-2° C. Irradiated samples were thermal-cycled to test for radiation-induced intolerance to thermal expansion. Mechanical vibrations of PU-coated wire bonds (99% aluminum, 1% silicon, 25 μ m diameter) were excited with 50% duty-cycle square wave currents in a 1.0 T field. The most vulnerable endcap disk geometry (magnetic field perpendicular to the wire bond and parallel to the normal of its PC board) was used. Resonance characteristics have been measured up to anticipated lifetime doses.

  2. A Method for Measuring Thermal Radiation Properties of Semi—Transparent Films

    Institute of Scientific and Technical Information of China (English)

    Y.P.Zhang; X.S.Ge; 等

    1992-01-01

    This paper presents a method(F method)for determining the optical constants and the thicknesses of semitransparent thin films.It has the following distinctive features:high precision;rapid determination of the measured quantities;wide range of convergence of solutions;capable of judging whether of not the results are reasonable,In order to meet the needs of application and engineering desigen,a family of curves designated Fig.n-F was prepared.Using it n,k,d of the thicknesses of the films determined by the F method.all important thermal radiation properties of the semi-transparent films needed in application can be obtained.

  3. Physical properties and biocompatibility of UHMWPE-derived materials modified by synchrotron radiation.

    Science.gov (United States)

    Bykova, Iu; Weinhardt, V; Kashkarova, A; Lebedev, S; Baumbach, T; Pichugin, V; Zaitsev, K; Khlusov, I

    2014-08-01

    The applications of synchrotron radiation (SR) in medical imaging have become of great use, particularly in angiography, bronchography, mammography, computed tomography, and X-ray microscopy. Thanks to recently developed phase contrast imaging techniques non-destructive preclinical testing of low absorbing materials such as polymers has become possible. The focus of the present work is characterization and examination of UHMWPE-derived materials widely used in medicine, before and after their exposure to SR during such testing. Physical properties, such as wettability, surface energy, IR-spectroscopy, roughness, optical microscopy, microhardness measurements of UHMWPE samples were studied before and after SR. The relationship between a growth of UHMWPE surface hydrophilicity after SR and surface colonization by stromal cells was studied in vitro. Obtained results demonstrate that SR may be used as prospective direction to examine bulk (porous) structure of polymer materials and/or to modify polymer surface and volume for tissue engineering.

  4. Physical properties of new collimator cone system for stereotactic radiation therapy developed in samsung medical center.

    Science.gov (United States)

    Kim, D Y; Ahn, Y C; Oh, D G; Choi, D R; Ju, S G; Yeo, I H; Huh, S J

    2000-09-01

    A new collimator cone system has been developed at the Samsung Medical Center that overcomes some of the limitations of present commercially supplied collimator cones. The physical properties of the newly developed cone system are described in this report. The new cones have relatively larger aperture sizes (3.0-7.0 cm in diameter) and are 16 cm in length. Each new cone is fabricated with cerrobend alloy melted and poured into a stainless steel housing that is permanently fixed to a mounting plate. The mounting plate of the new cone is designed to insert into the wedge mount slot of the gantry head. The mechanical accuracy of the central axis of the cone pointing to the isocenter was tested using film, a steel ball positioned at the isocenter by the mechanical isocenter device. For the evaluation of beam flatness and penumbra, off-axis ratios at 5 cm depth were measured by film dosimetry using polystyrene phantom. The average error of the mechanical isocenter was 0.27 mm (+/- 0.16 mm). The beam flatness was excellent in the central region of the beam, and the average penumbra width was 3.35 mm (+/- 0.25 mm). The new cone design has more clearance between the patient's head and the gantry, and can more easily be removed from the gantry head because it slides in and out of the wedge slot. This facilitates changing cone sizes during one treatment session, and makes the process of double exposure port films easier. A new collimator cone system for stereotactic radiation therapy has been developed. The mechanical accuracy and physical properties are satisfactory for clinical use, and the new design permits a wider range of clinical applications for stereotactic radiation therapy.

  5. On the radiative properties of soot aggregates - Part 2: Effects of coating

    Science.gov (United States)

    Liu, Fengshan; Yon, Jérôme; Bescond, Alexandre

    2016-03-01

    The effects of weakly absorbing material coating on soot have attracted considerable research attention in recent years due to the significant influence of such coating on soot radiative properties and the large differences predicted by different numerical models. Soot aggregates were first numerically generated using the diffusion limited cluster aggregation algorithm to produce fractal aggregates formed by log-normally distributed polydisperse spherical primary particles in point-touch. These aggregates were then processed by adding a certain amount of primary particle overlapping and necking to simulate the soot morphology observed from transmission electron microscopy images. After this process, a layer of WAM coating of different thicknesses was added to these more realistic soot aggregates. The radiative properties of these coated soot aggregates over the spectral range of 266-1064 nm were calculated by the discrete dipole approximation (DDA) using the spectrally dependent refractive index of soot for four aggregates containing Np=1, 20, 51 and 96 primary particles. The considered coating thicknesses range from 0% (no coating) up to 100% coating in terms of the primary particle diameter. Coating enhances both the particle absorption and scattering cross sections, with much stronger enhancement to the scattering one, as well as the asymmetry factor and the single scattering albedo. The absorption enhancement is stronger in the UV than in the visible and the near infrared. The simple corrections to the Rayleigh-Debye-Gans fractal aggregates theory for uncoated soot aggregates are found not working for coated soot aggregates. The core-shell model significantly overestimates the absorption enhancement by coating in the visible and the near infrared compared to the DDA results of the coated soot particle. Treating an externally coated soot aggregate as an aggregate formed by individually coated primary particles significantly underestimates the absorption

  6. Influence of atomic kinetics in the simulation of plasma microscopic properties and thermal instabilities for radiative bow shock experiments

    Science.gov (United States)

    Espinosa, G.; Rodríguez, R.; Gil, J. M.; Suzuki-Vidal, F.; Lebedev, S. V.; Ciardi, A.; Rubiano, J. G.; Martel, P.

    2017-03-01

    Numerical simulations of laboratory astrophysics experiments on plasma flows require plasma microscopic properties that are obtained by means of an atomic kinetic model. This fact implies a careful choice of the most suitable model for the experiment under analysis. Otherwise, the calculations could lead to inaccurate results and inappropriate conclusions. First, a study of the validity of the local thermodynamic equilibrium in the calculation of the average ionization, mean radiative properties, and cooling times of argon plasmas in a range of plasma conditions of interest in laboratory astrophysics experiments on radiative shocks is performed in this work. In the second part, we have made an analysis of the influence of the atomic kinetic model used to calculate plasma microscopic properties of experiments carried out on magpie on radiative bow shocks propagating in argon. The models considered were developed assuming both local and nonlocal thermodynamic equilibrium and, for the latter situation, we have considered in the kinetic model different effects such as external radiation field and plasma mixture. The microscopic properties studied were the average ionization, the charge state distributions, the monochromatic opacities and emissivities, the Planck mean opacity, and the radiative power loss. The microscopic study was made as a postprocess of a radiative-hydrodynamic simulation of the experiment. We have also performed a theoretical analysis of the influence of these atomic kinetic models in the criteria for the onset possibility of thermal instabilities due to radiative cooling in those experiments in which small structures were experimentally observed in the bow shock that could be due to this kind of instability.

  7. Study of surface properties of ATLAS12 strip sensors and their radiation resistance

    Energy Technology Data Exchange (ETDEWEB)

    Mikestikova, M., E-mail: mikestik@fzu.cz [Academy of Sciences of the Czech Republic, Institute of Physics, Na Slovance 2, 18221 Prague 8 (Czech Republic); Allport, P.P.; Baca, M.; Broughton, J.; Chisholm, A.; Nikolopoulos, K.; Pyatt, S.; Thomas, J.P.; Wilson, J.A. [School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT (United Kingdom); Kierstead, J.; Kuczewski, P.; Lynn, D. [Brookhaven National Laboratory, Physics Department and Instrumentation Division, Upton, NY 11973-5000 (United States); Hommels, L.B.A. [Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Ullan, M. [Centro Nacional de Microelectronica (IMB-CNM, CSIC), Campus UAB-Bellaterra, 08193 Barcelona (Spain); Bloch, I.; Gregor, I.M.; Tackmann, K. [DESY, Notkestrasse 85, 22607 Hamburg (Germany); Hauser, M.; Jakobs, K.; Kuehn, S. [Physikalisches Institut, Universität Freiburg, Hermann-Herder-Str. 3, D-79104 Freiburg (Germany); and others

    2016-09-21

    A radiation hard n{sup +}-in-p micro-strip sensor for the use in the Upgrade of the strip tracker of the ATLAS experiment at the High Luminosity Large Hadron Collider (HL-LHC) has been developed by the “ATLAS ITk Strip Sensor collaboration” and produced by Hamamatsu Photonics. Surface properties of different types of end-cap and barrel miniature sensors of the latest sensor design ATLAS12 have been studied before and after irradiation. The tested barrel sensors vary in “punch-through protection” (PTP) structure, and the end-cap sensors, whose stereo-strips differ in fan geometry, in strip pitch and in edge strip ganging options. Sensors have been irradiated with proton fluences of up to 1×10{sup 16} n{sub eq}/cm{sup 2}, by reactor neutron fluence of 1×10{sup 15} n{sub eq}/cm{sup 2} and by gamma rays from {sup 60}Co up to dose of 1 MGy. The main goal of the present study is to characterize the leakage current for micro-discharge breakdown voltage estimation, the inter-strip resistance and capacitance, the bias resistance and the effectiveness of PTP structures as a function of bias voltage and fluence. It has been verified that the ATLAS12 sensors have high breakdown voltage well above the operational voltage which implies that different geometries of sensors do not influence their stability. The inter-strip isolation is a strong function of irradiation fluence, however the sensor performance is acceptable in the expected range for HL-LHC. New gated PTP structure exhibits low PTP onset voltage and sharp cut-off of effective resistance even at the highest tested radiation fluence. The inter-strip capacitance complies with the technical specification required before irradiation and no radiation-induced degradation was observed. A summary of ATLAS12 sensors tests is presented including a comparison of results from different irradiation sites. The measured characteristics are compared with the previous prototype of the sensor design, ATLAS07. - Highlights:

  8. Radiative properties of Bay of Bengal aerosols: Spatial distinctiveness and source impacts

    Science.gov (United States)

    Babu, S. Suresh; Gogoi, Mukunda M.; Kumar, V. H. Arun; Nair, Vijayakumar S.; Moorthy, K. Krishna

    2012-03-01

    Simultaneous and collocated measurements of spectrally resolved scattering and absorption coefficients and mass concentration of near-surface composite aerosols in the marine atmosphere over the Bay of Bengal (BOB), along with incoming shortwave (0.3-3 μm) global solar radiation and columnar spectral aerosol optical depths (AOD), were made on a research cruise during the winter phase of the Integrated Campaign for Aerosols, Gases and Radiation Budget (W-ICARB). The aerosol radiative properties revealed distinct spatial features associated with the contrasting outflows from Indo-Gangetic Plain (IGP) and East Asia. Both scattering and absorption coefficients depicted very high values (>200 and >15 Mm-1) over the northwestern and southeastern BOB and extremely low values (<50 and <10 Mm-1) over the central BOB. The mean value of the total scattering coefficient at 550 nm (˜123.7 ± 85.3 Mm-1) over the entire BOB during winter was higher than the mean values (˜94 ± 47 Mm-1) reported for the premonsoon season. While SSA at 550 nm showed very low values (<0.8) over a very large region in the central BOB and moderately low values over the southern BOB (˜0.85-0.9), the columnar AOD varied from the least values of ˜0.1 over the northeastern BOB to the highest values of ˜0.8 over the northwestern BOB. While significant cooling was observed at the top of the atmosphere and surface over the northwestern BOB, the atmospheric forcing was found to be significantly high (˜15 W m-2) over the southern BOB, where the aerosol radiative forcing efficiency (ARFE) at the surface was also found to be high. Examination of the Moderate Resolution Imaging Spectroradiometer (MODIS)-derived fire count along with the advection pathways revealed a strong contribution from the emissions of biomass smoke from East Asia, which might be contributing to the enhanced aerosol induced warming over the southern BOB. However, the ARFE at the surface was low over the northwestern BOB, where the

  9. Evaluation of the sealing properties and TMA study of multilayer PA/PE film treated with e-beam radiation

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz, Angel V.; Gargalaka Junior, Joao [UNIPAC Embalagens Ltda., Sao Paulo, SP (Brazil)]. E-mail: angel.ortiz@unipacnet.com.br; joao.gargalaka@unipacnet.com.br; Wiebeck, Helio [Universidade de Sao Paulo (USP), SP (Brazil). Escola Politecnica]. E-mail: hwiebeck@usp.br

    2007-07-01

    Multilayer films are widely used in the food industry as thermoforming as well as non thermoforming vacuum packaging. In this study a PA6/LDPE multilayer film underwent E-beam radiation and its sealing properties were evaluated over 3 years after the film was irradiated. Packaging materials have been widely processed by ionizing radiation in order to improve their chemical and physical properties and also for sterilization purposes. Basically, flexible packaging manufacturers apply specific radiation doses to promote cross-linking and scission of the polymeric chains and thus obtain alterations in certain properties. While enhancing a specific property, significant losses may result in others. We examined the effects of E-beam radiation on the sealing properties of the multilayer film irradiated with doses up to 127 kGy. Results showed that as doses go up, the sealing strength goes down. The TMA study shows that the softening/melting temperatures of the LDPE layer (sealing layer) varies according to the irradiation doses and helps explain the results of the sealing strength tests. (author)

  10. Properties of a local dust storm on Mars' Atlantis Chaos by means of radiative transfer modeling.

    Science.gov (United States)

    Oliva, Fabrizio; Altieri, Francesca; Geminale, Anna; Bellucci, Giancarlo; D'Aversa, Emiliano; Carrozzo, Giacomo; Sindoni, Giuseppe; Grassi, Davide

    2017-04-01

    In this study we present the analysis of the dust properties in a local storm imaged in the Atlantis Chaos region on Mars by the OMEGA spectrometer (Bibring et al., 2004) on March 2nd 2005 (ORB1441_5). By means of an inverse radiative transfer code we study the dust properties across the region and try to infer the connection be-tween the local storm dynamics and the orography. OMEGA is a visible and near-IR mapping spectrometer, operating in the spectral range 0.38-5.1 μm with three separate channels with different spectral resolution. The instrument's IFOV is 1.2 mrad. To analyze the storm properties we have used the inverse radiative transfer model MITRA (Oliva et al., 2016; Sindoni et al., 2013) to retrieve the effective radius reff, the optical depth at 880 nm τ880 and the top pressure tp of the dust layer. We used the Mars Climate Database (MCD, Forget et al., 1999) to obtain the atmospheric properties of the studied region to be used as input in our model. Moreover we used the optical constants from Wolff et al. (2009) to describe the dust composition. The properties from the surface have been obtained by ap-plying the SAS method (Geminale et al., 2015) to observations of the same region relatively clear from dust. All retrievals have been performed in the spectral range 500 ÷ 2500 nm. Here we describe the result from our analysis carried out on selected regions of the storm and characterized by a different optical depth of the dust. Aknowledgements: This study has been performed within the UPWARDS project and funded in the context of the European Union's Horizon 2020 Programme (H2020-Compet-08-2014), grant agreement UPWARDS-633127. References: Bibring, J-P. et al., 2004. OMEGA: Observatoire pour la Minéralogie, l'Eau, les Glaces et l'Activité. Mars Express: the scientific payload, Ed. by Andrew Wilson, scientific coordination: Agustin Chicarro. ESA SP-1240, Noordwijk, Netherlands: ESA Publications Division, ISBN 92-9092-556-6, 2004, p. 37 - 49. Forget

  11. Low dark current MCT-based focal plane detector arrays for the LWIR and VLWIR developed at AIM

    Science.gov (United States)

    Gassmann, Kai Uwe; Eich, Detlef; Fick, Wolfgang; Figgemeier, Heinrich; Hanna, Stefan; Thöt, Richard

    2015-10-01

    For nearly 40 years AIM develops, manufactures and delivers photo-voltaic and photo-conductive infrared sensors and associated cryogenic coolers which are mainly used for military applications like pilotage, weapon sights, UAVs or vehicle platforms. In 2005 AIM started to provide the competences also for space applications like IR detector units for the SLSTR instrument on board of the Sentinel 3 satellite, the hyperspectral SWIR Imager for EnMAP or pushbroom detectors for high resolution Earth observation satellites. Meanwhile AIM delivered more than 25 Flight Models for several customers. The first European pulse-tube cooler ever operating on-board of a satellite is made by AIM. AIM homes the required infrared core capabilities such as design and manufacturing of focal plane assemblies, detector housing technologies, development and manufacturing of cryocoolers and also data processing for thermal IR cameras under one roof which enables high flexibility to react to customer needs and assures economical solutions. Cryogenically cooled Hg(1-x)CdxTe (MCT) quantum detectors are unequalled for applications requiring high imaging as well as high radiometric performance in the infrared spectral range. Compared with other technologies, they provide several advantages, such as the highest quantum efficiency, lower power dissipation compared to photoconductive devices and fast response times, hence outperforming micro-bolometer arrays. However, achieving an excellent MCT detector performance at long (LWIR) and very long (VLWIR) infrared wavelengths is challenging due to the exponential increase in the thermally generated photodiode dark current with increasing cut-off wavelength and / or operating temperature. Dark current is a critical design driver, especially for LWIR / VLWIR multi-spectral imagers with moderate signal levels or hyper-spectral Fourier spectrometers operating deep into the VLWIR spectral region. Consequently, low dark current (LDC) technologies are the

  12. Impact of precursor purity on optical properties and radiation detection of CsI:Tl scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Saengkaew, Phannee; Cheewajaroen, Kulthawat; Yenchai, Chadet; Thong-aram, Decho [Chulalongkorn University, Department of Nuclear Engineering, Faculty of Engineering, Bangkok (Thailand); Sanorpim, Sakuntam [Chulalongkorn University, Department of Physics, Faculty of Science, Bangkok (Thailand); Jitpukdee, Manit [Kasetsart University, Department of Applied Radiation and Isotope, Faculty of Science, Bangkok (Thailand); Yordsri, Visittapong; Thanachayanont, Chanchana [Ministry of Science and Technology, National Metal and Materials Technology Center, National Science and Technology Development Agency, Pathumthani (Thailand); Nuntawong, Noppadon [Ministry of Science and Technology, National Electronic and Computer Technology Center, National Science and Technology Development Agency, Pathumthani (Thailand)

    2016-08-15

    Cesium iodide doped with thallium (CsI:Tl) crystals was grown to develop the gamma-ray detectors by using low-cost raw materials. Effect of impurities on optical properties and radiation detection performance was investigated. By a modified homemade Bridgman-Stockbarger technique, CsI:Tl samples were grown in two levels of CsI and TlI reactant materials, i.e., having as a very high purity of 99.999 % and a high purity of 99.9 %. XRD measurements indicate CsI:Tl crystals having a good quality with a dominant (110) plane. Having a cubic structure, a lattice constant of CsI crystals of 0.4574 nm and a crystallite size of 43.539 nm were obtained. From the lower-purity raw materials, calcite was found in an orange crystal with a lattice constant of 0.4560 nm and a crystallite size of 43.089 nm. By PL measurements, the optical properties of the CsI:Tl crystals were analyzed. ∝540-nm-wavelength PL peak was observed from the colorless high-purity crystal, and ∝600-nm-wavelength PL peak was observed from the orange crystal. The brighter PL emission was obtained from the orange crystals suggesting impurities. CsI:Tl surface morphology by SEM exhibited a smooth surface with some parallel crystal facets. For electrical properties of high-quality CsI:Tl crystals, the electrical resistances were 230 ± 16 MΩ in cross-sectional direction and 714 ± 136 MΩ in vertical direction with respect to more homogeneous crystal quality in cross-sectional direction than that in vertical direction. TEM measurement was applied to evaluate the microstructure of colorless CsI:Tl crystal with different patterns of a cubic structure. Both CsI:Tl crystals show good efficiencies and good resolutions. Maintaining the same electronic conditions and amplifications, the colorless CsI:Tl scintillators represented a higher detection efficiency at 122 keV of Co-57 of 78.4 % and the energy resolution of 23.3 % compared to the detection efficiency of 75.9 % and the energy resolution of 34.6 % of the

  13. Effect of sea breeze circulation on aerosol mixing state and radiative properties in a desert setting

    Science.gov (United States)

    Derimian, Yevgeny; Choël, Marie; Rudich, Yinon; Deboudt, Karine; Dubovik, Oleg; Laskin, Alexander; Legrand, Michel; Damiri, Bahaiddin; Koren, Ilan; Unga, Florin; Moreau, Myriam; Andreae, Meinrat O.; Karnieli, Arnon

    2017-09-01

    Chemical composition, microphysical, and optical properties of atmospheric aerosol deep inland in the Negev Desert of Israel are found to be influenced by daily occurrences of sea breeze flow from the Mediterranean Sea. Abrupt increases in aerosol volume concentration and shifts of size distributions towards larger sizes, which are associated with increase in wind speed and atmospheric water content, were systematically recorded during the summertime at a distance of at least 80 km from the coast. Chemical imaging of aerosol samples showed an increased contribution of highly hygroscopic particles during the intrusion of the sea breeze. Besides a significant fraction of marine aerosols, the amount of internally mixed marine and mineral dust particles was also increased during the sea breeze period. The number fraction of marine and internally mixed particles during the sea breeze reached up to 88 % in the PM1-2. 5 and up to 62 % in the PM2. 5-10 size range. Additionally, numerous particles with residuals of liquid coating were observed by SEM/EDX analysis. Ca-rich dust particles that had reacted with anthropogenic nitrates were evidenced by Raman microspectroscopy. The resulting hygroscopic particles can deliquesce at very low relative humidity. Our observations suggest that aerosol hygroscopic growth in the Negev Desert is induced by the daily sea breeze arrival. The varying aerosol microphysical and optical characteristics perturb the solar and thermal infrared radiations. The changes in aerosol properties induced by the sea breeze, relative to the background situation, doubled the shortwave radiative cooling at the surface (from -10 to -20.5 W m-2) and increased by almost 3 times the warming of the atmosphere (from 5 to 14 W m-2), as evaluated for a case study. Given the important value of observed liquid coating of particles, we also examined the possible influence of the particle homogeneity assumption on the retrieval of aerosol microphysical characteristics

  14. Biomass burning aerosol over the Amazon during SAMBBA: impact of chemical composition on radiative properties

    Science.gov (United States)

    Morgan, William; Allan, James; Flynn, Michael; Darbyshire, Eoghan; Hodgson, Amy; Liu, Dantong; O'shea, Sebastian; Bauguitte, Stephane; Szpek, Kate; Langridge, Justin; Johnson, Ben; Haywood, Jim; Longo, Karla; Artaxo, Paulo; Coe, Hugh

    2014-05-01

    Biomass burning represents one of the largest sources of particulate matter to the atmosphere, resulting in a significant perturbation to the Earth's radiative balance coupled with serious impacts on public health. Globally, biomass burning aerosols are thought to exert a small warming effect but with the uncertainty being 4 times greater than the central estimate. On regional scales, the impact is substantially greater, particularly in areas such as the Amazon Basin where large, intense and frequent burning occurs on an annual basis for several months. Absorption by atmospheric aerosols is underestimated by models over South America, which points to significant uncertainties relating to Black Carbon (BC) aerosol properties. Initial results from the South American Biomass Burning Analysis (SAMBBA) field experiment, which took place during September and October 2012 over Brazil on-board the UK Facility for Airborne Atmospheric Measurement (FAAM) BAe-146 research aircraft, are presented here. Aerosol chemical composition was measured by an Aerodyne Aerosol Mass Spectrometer (AMS) and a DMT Single Particle Soot Photometer (SP2). The physical, chemical and optical properties of the aerosols across the region will be characterized in order to establish the impact of biomass burning on regional air quality, weather and climate. The aircraft sampled a range of conditions including sampling of pristine Rainforest, fresh biomass burning plumes, regional haze and elevated biomass burning layers within the free troposphere. The aircraft sampled biomass burning aerosol across the southern Amazon in the states of Rondonia and Mato Grosso, as well as in a Cerrado (Savannah-like) region in Tocantins state. This presented a range of fire conditions, both in terms of their number, intensity, vegetation-type and their combustion efficiencies. Near-source sampling of fires in Rainforest environments suggested that smouldering combustion dominated, while flaming combustion dominated

  15. Modelling the dust emission from dense interstellar clouds: disentangling the effects of radiative transfer and dust properties

    OpenAIRE

    Ysard, N.; Juvela, M.; Demyk, K.; Guillet, V.; Abergel, A.; Bernard, J. -P.; Malinen, J.; Mény, C.; Montier, L.; Paradis, D.; Ristorcelli, I.; L. Verstraete

    2012-01-01

    With Planck and Herschel, we now have the spectral coverage and angular resolution required to observe dense and cold molecular clouds. As these clouds are optically thick at short wavelength but optically thin at long wavelength, it is tricky to conclude anything about dust properties without a proper treatment of the radiative transfer (RT). Our aim is to disentangle the effects of RT and of dust properties on the variations in the dust emission to provide observers with keys to analyse the...

  16. The evaluation of properties for radiation therapy techniques with flattening filter-free beam and usefulness of time and economy to a patient with the radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Goo, Jang Hyeon; Won, Hui Su; Hong, Joo Wan; Chang, Nam Jun; Park, Jin Hong [Dept. of Radiation Oncology, Seoul national university Bundang hospital, Sungnam (Korea, Republic of)

    2014-12-15

    The aim of this study was to appraise properties for radiation therapy techniques and effectiveness of time and economy to a patient in the case of applying flattening filter-free (3F) and flattening filter (2F) beam to the radiation therapy. Alderson rando phantom was scanned for computed tomography image. Treatment plans for intensity modulated radiation therapy (IMRT), volumetric modulated arc therapy (VMAT) and stereotactic body radiation therapy (SBRT) with 3F and 2F beam were designed for prostate cancer. To evaluate the differences between the 3F and 2F beam, total monitor units (MUs), beam on time (BOT) and gantry rotation time (GRT) were used and measured with TrueBeam{sup TM} STx and Surveillance And Measurement (SAM) 940 detector was used for photoneutron emitted by using 3F and 2F. To assess temporal and economical aspect for a patient, total treatment periods and medical fees were estimated. In using 3F beam, total MUs in IMRT plan increased the highest up to 34.0% and in the test of BOT, GRT and photoneutron, the values in SBRT plan decreased the lowest 39.8, 38.6 and 48.1%, respectively. In the temporal and economical aspect, there were no differences between 3F and 2F beam in all of plans and the results showed that 10 days and 169,560 won was lowest in SBRT plan. According as the results, total MUs increased by using 3F beam than 2F beam but BOT, GRT and photoneutron decreased. From above the results, using 3F beam can decrease intra-fraction setup error and risk of radiation-induced secondary malignancy. But, using 3F beam did not make the benefits of temporal and economical aspect for a patient with the radiation therapy.

  17. On the radiative and thermodynamic properties of the cosmic radiations using COBE FIRAS instrument data: III. Galactic far-infrared radiation

    CERN Document Server

    Fisenko, Anatoliy I

    2014-01-01

    Using the three-component spectral model describing the FIRAS average continuum spectra, the analytical expressions for the temperature dependence of the thermodynamic and radiative functions of the galactic far-infrared radiation are obtained. The COBE FIRAS instrument data in the 0.15 - 2.88 THz frequency interval at the mean temperatures T = 17.72 K, T = 14 K, and T =6.73 K are used for calculating the radiative and thermodynamic functions, such as the total radiation power per unit area, total energy density, total emissivity, number density of photons, Helmholtz free energy density, entropy density, heat capacity at constant volume and pressure for the warm, intermediate-temperature and very cold components of the Galactic continuum spectra. The generalized Stefan-Boltzmann laws for the warm, intermediate-temperature and very cold components are constructed. This result is important when we construct the cosmological models of radiative transfer in the inner Galaxy. Within the framework of the three- com...

  18. Effect of high energy β-radiation and addition of triallyl isocyanurate on the selected properties of polylactide

    Science.gov (United States)

    Malinowski, Rafał

    2016-06-01

    Comparison of some changes occurring in polylactide (PLA) due to high energy β-radiation and addition of triallyl isocyanurate (TAIC) was the main objective of the present study. It was found that irradiation of PLA by high energy β-radiation causes essential changes in its properties, that undergoes mainly degradation, to form a porous structure. The PLA degradation can be diminished by introduction into the polymer matrix of a low-molecular mass multifunctional compound like TAIC. Upon the electron radiation, effective crosslinking of PLA by TAIC occurs. Application of TAIC favorably influences hindering of the PLA degradation or, when the doses are very large, diminishes worsening of the PLA functional qualities. It was also found that the optimum crosslinking of PLA is obtained when the electron radiation doses of the range of 40-200 kGy are applied and the amount of TAIC equal 3-5 wt% is used.

  19. Effect of high energy β-radiation and addition of triallyl isocyanurate on the selected properties of polylactide

    Energy Technology Data Exchange (ETDEWEB)

    Malinowski, Rafał, E-mail: malinowskirafal@gmail.com

    2016-06-15

    Comparison of some changes occurring in polylactide (PLA) due to high energy β-radiation and addition of triallyl isocyanurate (TAIC) was the main objective of the present study. It was found that irradiation of PLA by high energy β-radiation causes essential changes in its properties, that undergoes mainly degradation, to form a porous structure. The PLA degradation can be diminished by introduction into the polymer matrix of a low-molecular mass multifunctional compound like TAIC. Upon the electron radiation, effective crosslinking of PLA by TAIC occurs. Application of TAIC favorably influences hindering of the PLA degradation or, when the doses are very large, diminishes worsening of the PLA functional qualities. It was also found that the optimum crosslinking of PLA is obtained when the electron radiation doses of the range of 40–200 kGy are applied and the amount of TAIC equal 3–5 wt% is used.

  20. Prediction of air-fuel and oxy-fuel combustion through a generic gas radiation property model

    DEFF Research Database (Denmark)

    Yin, Chungen

    2017-01-01

    Thermal radiation plays an important role in heat transfer in combustion furnaces. The weighted-sum-of-gray-gases model (WSGGM), representing a good compromise between computational efficiency and accuracy, is commonly used in computational fluid dynamics (CFD) modeling of combustion processes...... for evaluating gaseous radiative properties. However, the WSGGMs still have some limitations in practical use, e.g., unable to naturally accommodate different combustion environments, difficult to accurately address the variations in species concentrations in a flame, and inconvenient to account for the impacts...... of participating species other than H2O and CO2. As a result, WSGGMs with different coefficients have been published for specific applications. In this paper, a reliable generic model for gaseous radiation property calculation, which is a computationally efficient exponential wide band model (E-EWBM) applicable...

  1. Thermal radiative and thermodynamic properties of solid and liquid uranium and plutonium carbides in the visible-near infrared range

    CERN Document Server

    Fisenko, Anatoliy I

    2016-01-01

    The knowledge of thermal radiative and thermodynamic properties of uranium and plutonium carbides under extreme conditions is essential for designing a new metallic fuel materials for next generation of a nuclear reactor. The present work is devoted to the study of the thermal radiative and thermodynamic properties of liquid and solid uranium and plutonium carbides at their melting/freezing temperatures. The Stefan-Boltzmann law, total energy density, number density of photons, Helmholtz free energy density, internal energy density, enthalpy density, entropy density, heat capacity at constant volume, pressure, and normal total emissivity are calculated using experimental data for the frequency dependence of the normal spectral emissivity of liquid and solid uranium and plutonium carbides in the visible-near infrared range. It is shown that the thermal radiative and thermodynamic functions of uranium carbide have a slight difference during liquid-to-solid transition. Unlike UC, such a difference between these ...

  2. Evaluation of mechanical properties and DSC study of commercial multilayer PA/PE film treated with E-beam radiation

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz, Angel V. [UNIPAC Embalagens Ltda., Sao Paulo, SP (Brazil)]. E-mail: angel.ortiz@unipacnet.com; Moura, Esperidiana A.B. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)]. E-mail: eabmoura@ipen.br; Coelho, Antonio C.V. [Sao Paulo Univ., SP (Brazil). Escola Politecnica]. E-mail: acvcoelh@usp.br

    2005-07-01

    Packaging materials have been widely processed by ionizing radiation in order to improve their chemical and physical properties and also for sterilization purposes. Basically, flexible packaging manufacturers apply specific radiation doses to promote cross-linking and scission of the polymeric chains and thus obtain alterations in certain properties of the material. While enhancing a specific property, significant losses may result in others. In this study, we examined the effects of E-beam radiation on a commercial multilayer PA6/LDPE based film, irradiated with doses up to 127 kGy. Food producers mostly use this structure as a thermoforming bottom web for processed meat products. Two weeks after irradiation, tensile strength and elongation of the film were analyzed. Both mechanical properties were again analyzed 18 months after irradiation took place. Significant changes of mechanical properties were observed specially 18 months after irradiation. Once cross-linking and scission are able to affect the material crystalline arrangement and consequently cause properties changes, a DSC ( Differential Scanning Calorimetry) study was carried out for doses up to 130 kGy in order to verify such changes. (author)

  3. Retrieval of radiative and microphysical properties of clouds from multispectral infrared measurements

    Science.gov (United States)

    Iwabuchi, Hironobu; Saito, Masanori; Tokoro, Yuka; Putri, Nurfiena Sagita; Sekiguchi, Miho

    2016-12-01

    Satellite remote sensing of the macroscopic, microphysical, and optical properties of clouds are useful for studying spatial and temporal variations of clouds at various scales and constraining cloud physical processes in climate and weather prediction models. Instead of using separate independent algorithms for different cloud properties, a unified, optimal estimation-based cloud retrieval algorithm is developed and applied to moderate resolution imaging spectroradiometer (MODIS) observations using ten thermal infrared bands. The model considers sensor configurations, background surface and atmospheric profile, and microphysical and optical models of ice and liquid cloud particles and radiative transfer in a plane-parallel, multilayered atmosphere. Measurement and model errors are thoroughly quantified from direct comparisons of clear-sky observations over the ocean with model calculations. Performance tests by retrieval simulations show that ice cloud properties are retrieved with high accuracy when cloud optical thickness (COT) is between 0.1 and 10. Cloud-top pressure is inferred with uncertainty lower than 10 % when COT is larger than 0.3. Applying the method to a tropical cloud system and comparing the results with the MODIS Collection 6 cloud product shows good agreement for ice cloud optical thickness when COT is less than about 5. Cloud-top height agrees well with estimates obtained by the CO2 slicing method used in the MODIS product. The present algorithm can detect optically thin parts at the edges of high clouds well in comparison with the MODIS product, in which these parts are recognized as low clouds by the infrared window method. The cloud thermodynamic phase in the present algorithm is constrained by cloud-top temperature, which tends not to produce results with an ice cloud that is too warm and liquid cloud that is too cold.

  4. The footprints of 16 year trends of Arctic springtime cloud and radiation properties on September sea ice retreat

    Science.gov (United States)

    Huang, Yiyi; Dong, Xiquan; Xi, Baike; Dolinar, Erica K.; Stanfield, Ryan E.

    2017-02-01

    The most prominent September Arctic sea ice decline over the period of 2000-2015 occurs over the Siberian Sea, Laptev Sea, and Kara Sea. The satellite observed and retrieved sea ice concentration (SIC) and cloud/radiation properties over the Arctic (70°-90°N) have been used to investigate the impact of springtime cloud and radiation properties on September SIC variation. Positive trends of cloud fractions, cloud water paths, and surface downward longwave flux at the surface over the September sea ice retreat areas are found over the period of 1 March to 14 May, while negative trends are found over the period of 15 May to 28 June. The spatial distributions of correlations between springtime cloud/radiation properties and September SIC have been calculated, indicating that increasing cloud fractions and downward longwave flux during springtime tend to enhance sea ice melting due to strong cloud warming effect. Surface downward and upward shortwave fluxes play an important role from May to June when the onset of sea ice melting occurs. The comparison between linearly detrended and nondetrended of each parameter indicates that significant impact of cloud and radiation properties on September sea ice retreat occurs over the Chukchi/Beaufort Sea at interannual time scale, especially over the period of 31 March to 29 April, while strongest climatological trends are found over the Laptev/Siberian Sea.

  5. Interaction effects of radiation and convection measured by a thermal manikin wearing protective clothing with different radiant properties

    NARCIS (Netherlands)

    Havenith, G.; Wang, X.; Candas, V.; Hartog, E. den; Griefahn, B.; Holmér, I.; Meinander, H.; Richards, M.

    2005-01-01

    As part of the EU funded research project THERMPROTECT ('Thermal properties of protective clothing and their use') this paper deals with manikin experiments on the effects of heat radiation at different wind speeds, considering aspects related to the reflectivity of the clothing. A heated thermal

  6. The Preparation and Properties of Thermosensitive Hydrogels Based on Chitosan Grafted N-isopropylacrylamide via γ-Radiation

    Institute of Scientific and Technical Information of China (English)

    Hong CAI; Jing ZHANG; Zheng Pu ZHANG; Yan Geng ZHANG; Bing Lin HE

    2004-01-01

    Thermosensitive hydrogels were prepared by graft polymerization of chitosan and N-isopropylacrylamide via 60Co γ-radiation. The effects of monomer concentration and total irradiation dose on percent grafting and grafting efficiency were studied. The thermosensitivity and swelling properties of the hydrogels were investigated.

  7. Radiation-induced change of optical property of hydroxypropyl cellulose hydrogel containing methacrylate compounds: As a basis for development of a new type of radiation dosimeter

    Science.gov (United States)

    Yamashita, Shinichi; Hiroki, Akihiro; Taguchi, Mitsumasa

    2014-08-01

    Hydrogels with matrix of a cellulose derivative, hydrogel of hydroxpropyl cellulose (HPC), containing two of methacrylate compounds (2-hydroxyethyl methacrylate (HEMA) and poly(ethylene glycol) dimethacrylate (9G)) were irradiated with 60Co γ-rays. The gels become white with irradiation, and thus, could be candidates of a new type of radiation dosimeter utilized in radiation therapy because the gels become white with irradiation and can be confirmed directly by human eyes even at low doses of 1-2 Gy. Radiation-induced change of optical properties, haze value and UV-vis absorption spectrum, of the irradiated gels was measured. Dose response of the white turbidity appearance was different for different compositions of the methacrylate compounds as well as for different dose rates. The degree of the radiation-induced white turbidity was quantified by measuring haze value, showing linear dose response in low dose region (<2 Gy). We also analyzed the gels with a UV-vis spectrometer and HEMA- and 9G-rich gels gave different spectral shapes, indicating that there are at least two mechanisms leading to the white turbidity. In addition, dose rate dependence was smaller for 9G-rich gels than HEMA-rich gels in the range of 0.015-1.5 Gy/min.

  8. A detailed radiation heat transfer study of a dish-Stirling receiver: The impact of cavity wall radiation properties and cavity shapes

    Science.gov (United States)

    Garrido, Jorge; Wang, Wujun; Nilsson, Martin; Laumert, Björn

    2016-05-01

    A detailed 3-D radiation analysis of a dish-Stirling cavity receiver is carried out to estimate the cavity steady-state temperatures in order to assess the receiver integrity, lifetime and efficiency performance. For this purpose, a parabolic dish was modeled with 5.2 m focal length, 8.85 m aperture diameter and 2 mrad surface error. Three generic cavity shapes (cylindrical, diamond-shaped and reverse-conical) with three different emissivities (0.2, 0.4 and 0.7) are studied. Worst-case scenario heat generations (total absorbed radiation), maximum steady-state temperatures and energy balances of the cavities are calculated to evaluate the receiver performance. The results show that reverse-conical cavities can significantly reduce cavity wall peak temperatures (by 40-120 K), improve the temperature evenness and decrease the radiation losses by 4-5%. Regarding radiation properties, low reflectivities present lower steady-state temperatures even for low/moderate direct solar fluxes. Due to the lower temperatures, lower total thermal losses are also expected.

  9. Predicting Radiative Heat Transfer in Oxy-Methane Flame Simulations: An Examination of Its Sensitivities to Chemistry and Radiative Property Models

    Directory of Open Access Journals (Sweden)

    Hassan Abdul-Sater

    2015-01-01

    Full Text Available Measurements from confined, laminar oxy-methane flames at different O2/CO2 dilution ratios in the oxidizer are first reported with measurements from methane-air flames included for comparison. Simulations of these flames employing appropriate chemistry and radiative property modeling options were performed to garner insights into the experimental trends and assess prediction sensitivities to the choice of modeling options. The chemistry was modeled employing a mixture-fraction based approach, Eddy dissipation concept (EDC, and refined global finite rate (FR models. Radiative properties were estimated employing four weighted-sum-of-gray-gases (WSGG models formulated from different spectroscopic/model databases. The mixture fraction and EDC models correctly predicted the trends in flame length and OH concentration variations, and the O2, CO2, and temperature measurements outside the flames. The refined FR chemistry model predictions of CO2 and O2 deviated from their measured values in the flame with 50% O2 in the oxidizer. Flame radiant power estimates varied by less than 10% between the mixture fraction and EDC models but more than 60% between the different WSGG models. The largest variations were attributed to the postcombustion gases in the temperature range 500 K–800 K in the upper sections of the furnace which also contributed significantly to the overall radiative transfer.

  10. A tandem approach for collocated measurements of microphysical and radiative cirrus properties

    Science.gov (United States)

    Klingebiel, Marcus; Ehrlich, André; Finger, Fanny; Röschenthaler, Timo; Jakirlić, Suad; Voigt, Matthias; Müller, Stefan; Maser, Rolf; Wendisch, Manfred; Hoor, Peter; Spichtinger, Peter; Borrmann, Stephan

    2017-09-01

    Microphysical and radiation measurements were collected with the novel AIRcraft TOwed Sensor Shuttle (AIRTOSS) - Learjet tandem platform. The platform is a combination of an instrumented Learjet 35A research aircraft and an aerodynamic bird, which is detached from and retracted back to the aircraft during flight via a steel wire with a length of 4000 m. Both platforms are equipped with radiative, cloud microphysical, trace gas, and meteorological instruments. The purpose of the development of this tandem set-up is to study the inhomogeneity of cirrus as well as other stratiform clouds. Sophisticated numerical flow simulations were conducted in order to optimally integrate an axially asymmetric Cloud Combination Probe (CCP) inside AIRTOSS. The tandem platform was applied during measurements at altitudes up to 36 000 ft (10 970 m) in the framework of the AIRTOSS - Inhomogeneous Cirrus Experiment (AIRTOSS-ICE). Ten flights were performed above the North Sea and Baltic Sea to probe frontal and in situ formed cirrus, as well as anvil outflow cirrus. For one flight, cirrus microphysical and radiative properties displayed significant inhomogeneities resolved by both measurement platforms. The CCP data show that the maximum of the observed particle number size distributions shifts with decreasing altitude from 30 to 300 µm, which is typical for frontal, midlatitude cirrus. Theoretical considerations imply that cloud particle aggregation inside the studied cirrus is very unlikely. Consequently, diffusional growth was identified to be the dominant microphysical growth process. Measurements of solar downward and upward irradiances at 670 nm wavelength were conducted above, below, and in the cirrus on both the Learjet and AIRTOSS. The observed variability of the downward irradiance below the cirrus reflects the horizontal heterogeneity of the observed thin cirrus. Vertically resolved solar heating rates were derived by either using single-platform measurements at different

  11. 3D Gray Radiative Properties of Accretion Shocks in Young Stellar Objects

    Science.gov (United States)

    Ibgui, L.; Orlando, S.; Stehlé, C.; Chièze, J.-P.; Hubeny, I.; Lanz, T.; de Sá, L.; Matsakos, T.; González, M.; Bonito, R.

    2014-01-01

    We address the problem of the contribution of radiation to the structure and dynamics of accretion shocks on Young Stellar Objects. Solving the 3D RTE (radiative transfer equation) under our "gray LTE approach", i.e., using appropriate mean opacities computed in local thermodynamic equilibrium, we post-process the 3D MHD (magnetohydrodynamic) structure of an accretion stream impacting the stellar chromosphere. We find a radiation flux of ten orders of magnitude larger than the accreting energy rate, which is due to a large overestimation of the radiative cooling. A gray LTE radiative transfer approximation is therefore not consistent with the given MHD structure of the shock. Further investigations are required to clarify the role of radiation, by relaxing both the gray and LTE approximations in RHD (radiation hydrodynamics) simulations. Post-processing the obtained structures through the resolution of the non-LTE monochromatic RTE will provide reference radiation quantities against which RHD approximate solutions will be compared.

  12. Monthly-averaged anthropogenic aerosol direct radiative forcing over the Mediterranean based on AERONET aerosol properties

    Directory of Open Access Journals (Sweden)

    A. Bergamo

    2008-12-01

    Full Text Available The all-sky direct radiative effect by anthropogenic aerosol (DREa is calculated in the solar (0.3–4 μm and infrared (4–200 μm spectral ranges for six Mediterranean sites. The sites are differently affected by pollution and together reflect typical aerosol impacts that are expected over land and coastal sites of the central Mediterranean basin. Central to the simulations are aerosol optical properties from AERONET sun-/sky-photometer statistics for the year 2003. A discussion on the variability of the overall (natural + anthropogenic aerosol properties with site location is provided. Supplementary data include MODIS satellite sensor based solar surface albedos, ISCCP products for high- mid- and low cloud cover and estimates for the anthropogenic aerosol fraction from global aerosol models. Since anthropogenic aerosol particles are considered to be smaller than 1 μm in size, mainly the solar radiation transfer is affected with impacts only during sun-light hours. At all sites the (daily average solar DREa is negative all year round at the top of the atmosphere (ToA. Hence, anthropogenic particles produce over coastal and land sites of the central Mediterranean a significant cooling effect. Monthly DREa values vary from site to site and are seasonally dependent as a consequence of the seasonal dependence of available sun-light and microphysical aerosol properties. At the ToA the monthly average DREa is −(4±1 W m−2 during spring-summer (SS, April–September and −(2±1 W m−2 during autumn-winter (AW, October–March at the polluted sites. In contrast, it varies between −(3±1 W m−2 and −(1±1 W m−2 on SS and AW, respectively at the less polluted site. Due to atmospheric absorption the DREa at the surface is larger than at the ToA. At the surface the monthly average DREa varies between the most and the least polluted

  13. The roadmap for low price- high performance IR detector based on LWIR to NIR light up-conversion approach

    Science.gov (United States)

    Kipper, R.; Arbel, D.; Baskin, E.; Fayer, A.; Epstein, A.; Shuall, N.; Saguy, A.; Veksler, D.; Spektor, B.; Ben-Aharon, D.; Garber, V.

    2009-05-01

    The introduction of an uncooled microbolometer image sensor about a decade ago enabled cost reduction of IR cameras. As a result, the available markets grew both in military and civilian applications. Since then, the price of microbolometer was gradually reduced due to introduction of devices with smaller pixel, maturity of the technology and quantity growth. However, the requirement for a vacuum package still limits the price of microbolometer based cameras to several thousands of dollars. Sirica's novel wavelength conversion technology aims at breaking this paradigm by being uncooled and vacuumless, lowering IR camera prices by an order of magnitude, opening the way to new mass markets. Sirica's proprietary IR-to-Visible/NIR conversion layer allows for low-cost high performance LWIR detector with no requirement for cooling and vacuum packaging. In the last years, the development efforts focused on development of the conversion media. Recently, a parallel effort for the integration of the conversion layer together with other detector components has started. Packaging of detector components, such as conversion layer, pumping light source, dichroic filter, and their coupling with silicon CMOS image sensor have great importance from a price-performance point of view. According to the company's business-development roadmap, the detector prototype should be available during the first quarter of 2010.

  14. Design of 90×8 ROIC with pixel level digital TDI implementation for scanning type LWIR FPAs

    Science.gov (United States)

    Ceylan, Omer; Kayahan, Huseyin; Yazici, Melik; Gurbuz, Yasar

    2013-06-01

    Design of a 90×8 CMOS readout integrated circuit (ROIC) based on pixel level digital time delay integration (TDI) for scanning type LWIR focal plane arrays (FPAs) is presented. TDI is implemented on 8 pixels which improves the SNR of the system with a factor of √8. Oversampling rate of 3 improves the spatial resolution of the system. TDI operation is realized with a novel under-pixel analog-to-digital converter, which improves the noise performance of ROIC with a lower quantization noise. Since analog signal is converted to digital domain in-pixel, non-uniformities and inaccuracies due to analog signal routing over large chip area is eliminated. Contributions of each pixel for proper TDI operation are added in summation counters, no op-amps are used for summation, hence power consumption of ROIC is lower than its analog counterparts. Due to lack of multiple capacitors or summation amplifiers, ROIC occupies smaller chip area compared to its analog counterparts. ROIC is also superior to its digital counterparts due to novel digital TDI implementation in terms of power consumption, noise and chip area. ROIC supports bi-directional scan, multiple gain settings, bypass operation, automatic gain adjustment, pixel select/deselect, and is programmable through serial or parallel interface. Input referred noise of ROIC is less than 750 rms electrons, while power consumption is less than 20mW. ROIC is designed to perform both in room and cryogenic temperatures.

  15. Radiation response and electrical properties of polymer energy storage capacitors: PVF2, Polysulfone, and Mylar

    Science.gov (United States)

    Edwards, L. R.

    1981-01-01

    Efforts were made to develop a polymer film capacitor that is tolerant to radiation. The capacitors are to be utilized in a high voltage pulse discharge application. Radiation response data at high dose/dose rate levels are presented for polyvinylidene fluoride (PVF2), polysulfone, and Mylar. The results show that PVF2 is the most radiation tolerant while Mylar is the least tolerant. The data also show that the radiation response is quite dependent on operating electric stress.

  16. Multiwalled carbon nanotubes and dispersed nanodiamond novel hybrids: Microscopic structure evolution, physical properties, and radiation resilience

    Science.gov (United States)

    Gupta, S.; Farmer, J.

    2011-01-01

    We report the structure and physical properties of novel hybrids of multiwalled carbon nanotubes (MWCNTs) and ultradispersed diamond (UDD) forming nanocomposite ensemble that were subjected to 50, 100, and 103 kGy gamma ray doses and characterized using various analytical tools to investigate hierarchical defects evolution. This work is prompted by recent work on single-walled CNTs and UDD ensemble [Gupta et al., J. Appl. Phys. 107, 104308 (2010)] where radiation-induced microscopic defects seem to be stabilized by UDD. The present experiments show similar effects where these hybrids display only a minimal structural modification under the maximum dose. Quantitative analyses of multiwavelength Raman spectra revealed lattice defects induced by irradiation assessed through the variation in prominent D, G, and 2D bands. A minimal change in the position of D, G, and 2D bands and a marginal increase in intensity of the defect-induced double resonant Raman scattered D and 2D bands are some of the implications suggesting the radiation coupling. The in-plane correlation length (La) was also determined following Tunistra-Koenig relation from the ratio of D to G band (ID/IG) besides microscopic stress. However, we also suggest the following taking into account of intrinsic defects of the constituents: (a) charge transfer arising at the interface due to the difference in electronegativity of MWCNT C sp2 and UDD core (C sp3) leading to phonon and electron energy renormalization; (b) misorientation of C sp2 at the interface of MWCNT and UDD shell (C sp2) resulting in structural disorder; (c) softening or violation of the q ˜0 selection rule leading to D band broadening and a minimal change in G band intensity; and (d) normalized intensity of D and G bands with 2D band help to distinguish defect-induced double resonance phenomena. The MWCNT when combined with nanodiamond showed a slight decrease in their conductance further affected by irradiation pointing at relatively good

  17. Aerosol Properties and Radiative Forcing over Kanpur during Severe Aerosol Loading Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Kaskaoutis, D. G.; Sinha, P. R.; Vinoj, V.; Kosmopoulos, P. G.; Tripathi, S. N.; Misra, Amit; Sharma, M.; Singh, R. P.

    2013-11-01

    Atmospheric aerosols over India exhibit large spatio-temporal fluctuation driven by the local monsoon system, emission rates and seasonally-changed air masses. The northern part of India is well-known for its high aerosol loading throughout the year due to anthropogenic emissions, dust influence and biomass burning. On certain circumstances and, under favorable weather conditions, the aerosol load can be severe, causing significant health concerns and climate implications. The present work analyzes the aerosol episode (AE) days and examines the modification in aerosol properties and radiative forcing during the period 2001-2010 based on Kanpur-AERONET sun photometer data. As AEs are considered the days having daily-mean aerosol optical depth (AOD) above the decadal mean + 1 STD (standard deviation); the threshold value is defined at 0.928. The results identify 277 out of 2095 days (13.2%) of AEs over Kanpur, which are most frequently observed during post-monsoon (78 cases, 18.6%) and monsoon (76, 14.7%) seasons due to biomass-burning episodes and dust influence, respectively. On the other hand, the AEs in winter and pre-monsoon are lower in both absolute and percentage values (65, 12.5% and 58, 9.1%, respectively). The modification in aerosol properties on the AE days is strongly related to season. Thus, in post-monsoon and winter the AEs are associated with enhanced presence of fine-mode aerosols and Black Carbon from anthropogenic pollution and any kind of burning, while in pre-monsoon and monsoon seasons they are mostly associated with transported dust. Aerosol radiative forcing (ARF) calculated using SBDART shows much more surface (~-69 to -97 Wm-2) and Top of Atmosphere cooling (-20 to -30 Wm-2) as well as atmospheric heating (~43 to 71 Wm-2) during the AE days compared to seasonal means. These forcing values are mainly controlled by the higher AODs and the modified aerosol characteristics (Angstrom α, SSA) during the AE days in each season and may cause

  18. A radiation closure study of Arctic stratus cloud microphysical properties using the collocated satellite-surface data and Fu-Liou radiative transfer model

    Science.gov (United States)

    Dong, Xiquan; Xi, Baike; Qiu, Shaoyue; Minnis, Patrick; Sun-Mack, Sunny; Rose, Fred

    2016-09-01

    Retrievals of cloud microphysical properties based on passive satellite imagery are especially difficult over snow-covered surfaces because of the bright and cold surface. To help quantify their uncertainties, single-layered overcast liquid-phase Arctic stratus cloud microphysical properties retrieved by using the Clouds and the Earth's Radiant Energy System Edition 2 and Edition 4 (CERES Ed2 and Ed4) algorithms are compared with ground-based retrievals at the Atmospheric Radiation Measurement North Slope of Alaska (ARM NSA) site at Barrow, AK, during the period from March 2000 to December 2006. A total of 206 and 140 snow-free cases (Rsfc ≤ 0.3), and 108 and 106 snow cases (Rsfc > 0.3), respectively, were selected from Terra and Aqua satellite passes over the ARM NSA site. The CERES Ed4 and Ed2 optical depth (τ) and liquid water path (LWP) retrievals from both Terra and Aqua are almost identical and have excellent agreement with ARM retrievals under snow-free and snow conditions. In order to reach a radiation closure study for both the surface and top of atmosphere (TOA) radiation budgets, the ARM precision spectral pyranometer-measured surface albedos were adjusted (63.6% and 80% of the ARM surface albedos for snow-free and snow cases, respectively) to account for the water and land components of the domain of 30 km × 30 km. Most of the radiative transfer model calculated SW↓sfc and SW↑TOA fluxes by using ARM and CERES cloud retrievals and the domain mean albedos as input agree with the ARM and CERES flux observations within 10 W m-2 for both snow-free and snow conditions. Sensitivity studies show that the ARM LWP and re retrievals are less dependent on solar zenith angle (SZA), but all retrieved optical depths increase with SZA.

  19. Effect of γ-radiation on free radicals formation, structural changes and functional properties of wheat starch.

    Science.gov (United States)

    Atrous, Hager; Benbettaieb, Nasreddine; Hosni, Faouzi; Danthine, Sabine; Blecker, Christophe; Attia, Hamadi; Ghorbel, Dorra

    2015-09-01

    Wheat starch was treated by different γ-radiation doses (3, 5, 10, 20, 35 and 50 kGy). The effects of γ-radiation on structural, thermal, physicochemical, morphological and rheological properties of wheat starch were studied. The presence of free radicals after γ-radiation treatment, which number decreased with time was confirmed. Structural analysis revealed decreases in the intensities of the O-H and C-H stretches and glycosidic linkages indicating the depolymerization of amylose and probably amylopectin into shorter chain molecules, but showed that γ-radiation treatment did not affect the crystalline structure. Differential scanning calorimetric (DSC) thermograms showed the absence of significant differences in the gelatinization temperatures, as well as the corresponding transition enthalpies since the DSC parameters are related to the crystalline ordering within the granules. Apparent amylose content decreased linearly with increasing irradiation dose leading to an increase in water solubility index. An increase in the swelling power was observed after irradiation treatment until 20 kGy, followed by a rapid decrease at higher doses. Microscopic observations showed that the effect of γ-radiation was more visible on starch pastes than on starch granules. Rheological properties of the starch pastes decreased with increasing irradiation dose as a result of glycosidic bond cleavage.

  20. Thermal radiative and thermodynamic properties of solid and liquid uranium and plutonium carbides in the visible-near-infrared range

    Science.gov (United States)

    Fisenko, Anatoliy I.; Lemberg, Vladimir F.

    2016-09-01

    The knowledge of thermal radiative and thermodynamic properties of uranium and plutonium carbides under extreme conditions is essential for designing a new metallic fuel materials for next generation of a nuclear reactor. The present work is devoted to the study of the thermal radiative and thermodynamic properties of liquid and solid uranium and plutonium carbides at their melting/freezing temperatures. The Stefan-Boltzmann law, total energy density, number density of photons, Helmholtz free energy density, internal energy density, enthalpy density, entropy density, heat capacity at constant volume, pressure, and normal total emissivity are calculated using experimental data for the frequency dependence of the normal spectral emissivity of liquid and solid uranium and plutonium carbides in the visible-near infrared range. It is shown that the thermal radiative and thermodynamic functions of uranium carbide have a slight difference during liquid-to-solid transition. Unlike UC, such a difference between these functions have not been established for plutonium carbide. The calculated values for the normal total emissivity of uranium and plutonium carbides at their melting temperatures is in good agreement with experimental data. The obtained results allow to calculate the thermal radiative and thermodynamic properties of liquid and solid uranium and plutonium carbides for any size of samples. Based on the model of Hagen-Rubens and the Wiedemann-Franz law, a new method to determine the thermal conductivity of metals and carbides at the melting points is proposed.

  1. Synthesis and characterization of gold/alanine nanocomposites with potential properties for medical application as radiation sensors.

    Science.gov (United States)

    Guidelli, Eder José; Ramos, Ana Paula; Zaniquelli, Maria Elisabete D; Nicolucci, Patricia; Baffa, Oswaldo

    2012-11-01

    Radiation dose assessment is essential for several medical treatments and diagnostic procedures. In this context, nanotechnology has been used in the development of improved radiation sensors, with higher sensitivity as well as smaller sizes and energy dependence. This paper deals with the synthesis and characterization of gold/alanine nanocomposites with varying mass percentage of gold, for application as radiation sensors. Alanine is an excellent stabilizing agent for gold nanoparticles because the size of the nanoparticles does not augment with increasing mass percentage of gold, as evidenced by UV-vis spectroscopy, dynamic light scattering, and transmission electron microscopy. X-ray diffraction patterns suggest that the alanine crystalline orientation undergoes alterations upon the addition of gold nanoparticles. Fourier transform infrared spectroscopy indicates that there is interaction between the gold nanoparticles and the amine group of the alanine molecules, which may be the reason for the enhanced stability of the nanocomposite. The application of the nanocomposites as radiation detectors was evaluated by the electron spin resonance technique. The sensitivity is improved almost 3 times in the case of the nanocomposite containing 3% (w/w) gold, so it can be easily tuned by changing the amount of gold nanoparticles in the nanocomposites, without the size of the nanoparticles influencing the radiation absorption. In conclusion, the featured properties, such as homogeneity, nanoparticle size stability, and enhanced sensitivity, make these nanocomposites potential candidates for the construction of small-sized radiation sensors with tunable sensitivity for application in several medical procedures.

  2. The effect of helium, radiation damage and irradiation temperature on the mechanical properties of beryllium

    Energy Technology Data Exchange (ETDEWEB)

    Fabritsiev, S.A. [D.V. Efremov Scientific Research Inst., St. Petersburg (Russian Federation); Pokrovsky, A.S.

    1998-01-01

    In this work different RF beryllium grades were irradiated in the BOR-60 reactor to a dose of {approx}5-10 dpa at irradiation temperatures 350, 420, 500, 800degC. Irradiation at temperatures of 350-400degC is shown to result in Be hardening due to the accumulation of radiation defect complexes. Hardening is accompanied with a sharp drop in plasticity at T{sub test} {<=} 300degC. A strong anisotropy in plasticity has been found at a mechanical testing temperature of 400degC and this parameter may be preferable when the samples are cut crosswise to the pressing direction. High-temperature irradiation (T{sub irr} = 780degC) gives rise to large helium pores over the grain boundaries and smaller pores in the grain body. Fracture is brittle and intercrystallite at T{sub test} {>=} 600degC. Helium embrittlement is accompanied as well with a drop in the Be strength properties. (author)

  3. Effects of nanoscale features on infrared radiative properties of heavily doped silicon complex gratings

    Institute of Scientific and Technical Information of China (English)

    HSU; PeiFeng

    2010-01-01

    The infrared radiative properties of one heavily doped silicon complex grating and its corresponding four modified complex gratings with attached features at transverse magnetic wave incidence were numerically investigated by employing the finite-difference time-domain method.For the complex grating,by properly choosing the carrier concentration and geometry,it exhibited a broadband absorptance peak at wavelengths between 7 and 12μm resulting from the excitation of surface plasmon polaritons.As for the four modified complex gratings,though absorptance spectra of the gratings almost remained unchanged, their locations shifted towards longer wavelengths.Meanwhile,the spectral absorptance peaks of two modified complex gratings were wider than that of the grating without attached features.Such broadened peaks could be partly attributed to the cavity resonance within the grating structures demonstrated by the electromagnetic fields and Poynting vectors plots.Finally,through comparing the spectral absorptances of complex gratings with two symmetrical square features in three sizes,it was shown that the peak wavelength shifted toward longer wavelengths with enlarged feature size.This work theoretically laid a foundation for the optimized design and application of the infrared detector with high performance.

  4. Antibacterial properties of Au doped polycarbonate synthesized by gamma radiation assisted diffusion method

    Science.gov (United States)

    Hareesh, K.; Deore, Avinash V.; Dahiwale, S. S.; Sanjeev, Ganesh; Kanjilal, D.; Ojha, Sunil; Dhole, N. A.; Kodam, K. M.; Bhoraskar, V. N.; Dhole, S. D.

    2015-07-01

    Gold (Au)-Polycarbonate (PC) matrix was prepared by gamma radiation assisted diffusion of Au nanoparticles in PC matrix. UV-Visible spectroscopy showed the surface plasmon resonance around 550 nm which corresponds to Au and this peak shift towards lower wavelength i.e. blue shift indicating the decrease in particle size of Au. Rutherford Backscattering (RBS) experiment confirmed the diffusion of Au in PC and depth of diffusion is found to be around 0.85 μm. X-ray Diffractogram (XRD) results also revealed the diffusion of Au in PC where the peak observed at 2θ∼38.29° which correspond to the FCC structure. Scanning Electron Microscope (SEM) images showed the hexagonal shaped Au nanoparticles and average particle size is found to be around 110 nm. These samples also showed anti-bacterial properties with both gram positive and gram negative bacteria's and revealed the inhibition of the overall growth of the bacteria with gamma dose.

  5. Terrestrial kilometric radiation. III - Average spectral properties. [observations by IMP-6 and RAE-2 satellites

    Science.gov (United States)

    Kaiser, M. L.; Alexander, J. K.

    1977-01-01

    The spectral properties of terrestrial kilometric radiation (TKR) derived from observations made during radio-astronomy experiments on board the Imp 6 and Radio Astronomy Explorer 2 spacecraft are studied. As viewed from near the equatorial plane, TKR is most intense and most often observed in the 2100-2400 LT zone and is rarely seen in the 0900-1200 LT zone. The absolute flux levels in the 100- to 600-kHz TKR band increase significantly with increasing substorm activity as inferred from the auroral electrojet index (AE). In the late-evening sector the median power increases by about 3 orders of magnitude between quiet periods (AE less than 75 gammas) and disturbed periods (AE above 200 gammas). The peak flux density usually occurs near 250 kHz, although the frequency of the peak in the flux spectrum appears to vary inversely with AE from a maximum near 300 kHz during very quiet times to a minimum below 200 kHz during very disturbed times. The half-power bandwidth is typically 100% of the peak frequency. The variation of TKR flux density with apparent source altitude indicates that source strength decreases more rapidly than the inverse square of distance.

  6. Intrinsic wave properties of Saturn Kilometric Radiation and evolution with propagation

    Science.gov (United States)

    Lamy, L.; Cecconi, B.; Zarka, P. M.; Cassini/Rpws, Mag; Caps Teams

    2010-12-01

    Investigating the crossing of the southern source region of Saturn Kilometric Radiation (SKR) by the Cassini spacecraft in late 2008, we review the intrinsic properties of SKR waves and their evolution with propagation through the kronian high-latitude plasma. In particular, we identify SKR magneto-ionic modes and estimate the electron/wave energy conversion efficiency thanks to in situ and remote observations. Then, we focus on the unusual locus of radio sources, illustrating an enhanced auroral activity. The beaming pattern is derived from different techniques for local and distant radio sources, and shows that kilometric waves are generally emitted at large angles with respect to the local magnetic field vector. Finally, we show that the SKR polarization is elliptical at the source, but becomes gradually circular along the ray path. The SKR polarization transfer is satisfactorily described in the frame of wave propagation in a cold plasma and conditions of weak mode coupling. SKR characteristics are analyzed comparatively to other equivalent auroral planetary radio emissions.

  7. Solar ultraviolet radiation: properties, characteristics and amounts observed in Brazil and South America.

    Science.gov (United States)

    Corrêa, Marcelo de Paula

    2015-01-01

    The beneficial and harmful effects of human exposure to solar ultraviolet radiation (UV-R) are topics that arouse great interest not only among physicians and scientists, but also the general public and the media. Currently, discussions on vitamin D synthesis (beneficial effect) are confronted with the high and growing number of new cases of non-melanoma skin cancer and other diseases of the skin and eyes (harmful effect) diagnosed each year in Brazil. However, the lack of scientific knowledge on the UV-R in Brazil and South America leads to adoption of protective measures based on studies conducted in Europe and USA, where the amounts of UV-R available at surface and the sun-exposure habits and characteristics of the population are significantly different from those observed in Brazil. In order to circumvent this problem, the Brazilian Society of Dermatology recently published the Brazilian Consensus of Photoprotection based on recent studies performed locally. The main goal of this article is to provide detailed educational information on the main properties and characteristics of UV-R and UV index in a simple language. It also provides: a) a summary of UV-R measurements recently performed in Brazil; b) a comparison with those performed in Europe; and, c) an evaluation to further clarify the assessment of potential harm and health effects owing to chronic exposures.

  8. A stochastic model of radiation carcinogenesis: Latent time distributions and their properties

    Energy Technology Data Exchange (ETDEWEB)

    Klebanov, L.V.; Yakovlev, A.Yu. (St. Petersburg Technical Univ. (Russian Federation)); Rachev, S.T. (Univ. of California, Santa Barbara (United States))

    1993-01-01

    A stochastic model of radiation carcinogenesis is proposed that has much in common with the ideas suggested by M. Pike as early as 1966. The model allows one to obtain a parametric family of substochastic-type distributions for the time of tumor latency that provides a description of the rate of tumor development and the number of affected individuals. With this model it is possible to interpret data on tumor incidence in terms of promotion and progression processes. The basic model is developed for a prolonged irradiation at a constant dose rate and includes short-term irradiation as a special case. A limiting form of the latent time distribution for short-term irradiation at high doses is obtained. This distribution arises in the extreme value theory within the random minima framework. An estimate for the rate of convergence to a limiting distributions is given. Based on the proposed latent time distributions, long-term predictions of carcinogenic risk do not call for information about irradiation dose. As shown by computer simulation studies and real data analysis, the parametric estimation of carcinogenic risk appears to be robust to the loss of statistical information caused by the right-hand censoring of time-to-tumor observations. It seems likely that this property, although revealed by means of a purely empirical procedure, may be useful in selecting a model for the practical purpose of risk prediction. 44 refs., 3 figs., 1 tab.

  9. Synthesis, characterization and properties of radiation-induced Starch/(EG-co-MAA hydrogels

    Directory of Open Access Journals (Sweden)

    H.L. Abd El-Mohdy

    2016-11-01

    Full Text Available Association of poly(carboxylic acids and non-ionic polymers in solutions via hydrogen bonding results in formation of novel polymeric materials–interpolymer complexes. Starch/(EG-co-MAA polymeric hydrogels were obtained by γ-initiated radiation copolymerization of ethylene glycol (EG with methacrylic acid (MAA which grafted on starch. The gel content of prepared hydrogels was varied with changes in starch content, EG:MAA composition and irradiation dose as well as crosslinking density. The swelling was studied as a function of starch content, EG:MAA composition, irradiation dose, type of soaked liquid, pH and temperature of matrix-surrounding medium. The degree of swelling greatly increased with enhanced MAA content, pH and temperature whereas, it decreased with reduced starch content and irradiation dose. The swelling was varied with the polarity of soaked liquid. The results showed that Starch/(EG-co-MAA hydrogels reached the equilibrium swelling state in water after 72 h. The structure and surface morphology of prepared polymer were confirmed with FTIR and SEM, respectively. The thermal properties of hydrogels were studied by using DSC and TGA, they cleared that there is miscibility between EG and MAA in copolymer and adding them improve the thermal stability of starch. The results indicate that Starch/(EG-co-MAA materials may be used in various applications.

  10. COMPARISON OF CHARACTERIZATION TECHNIQUES IN P-ON-N HgCdTe LWIR PHOTODIODES TECHNOLOGY

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In this paper standard techniques for characterization of HgCdTe liquid phase epitaxial layers (LPE) were presented. The performance of long wavelength p-on-n HgCdTe photodiodes fabricated by arsenic diffusion was described. The correlation between LPE HgCdTe material parameters and properties of the infrared photodiodes was demonstrated.

  11. Investigation of DEPFET as vertex detector at ILC. Intrinsic properties, radiation hardness and alternative readout schemes

    Energy Technology Data Exchange (ETDEWEB)

    Rummel, Stefan

    2009-07-20

    The International Linear Collider (ILC) is supposed to be the next generation lepton collider. The detectors at ILC are intended to be precision instruments improving the performance in impact parameter (IP), momentum and energy resolution significantly compared to previous detectors at lepton colliders. To achieve this goal it is necessary to develop new detector technologies or pushing existing technologies to their technological edges. Regarding the Vertex detector (VTX) this implies challenges in resolution, material budget, power consumption and readout speed. A promising technology for the Vertex detector is the Depleted Field Effect Transistor (DEPFET). The DEPFET is a semiconductor device with in-pixel ampli cation integrated on a fully depleted bulk. This allows building detectors with intrinsically high SNR due to the large sensitive volume and the small input capacitance at the rst ampli er. To reach the ambitious performance goals it is important to understand its various features: clear performance, internal amplification, noise and radiation hardness. The intrinsic noise is analyzed, showing that the contribution of the DEPFET is below 50 e{sup -} at the required speed. Moreover it is possible to show that the internal ampli cation could be further improved to more than 1nA/e{sup -} using the standard DEPFET technology. The clear performance is investigated on matrix level utilizing a dedicated setup for single pixel testing which allows direct insight into the DEPFET operation, without the complexity of the full readout system. It is possible to show that a full clear could be achieved with a voltage pulse of 10 V. Furthermore a novel clear concept - the capacitive coupled clear gate - is demonstrated. The radiation hardness is studied with respect to the system performance utilizing various irradiations with ionizing and non ionizing particles. The impact on the bulk as well as the interface damage is investigated. Up to now the readout is performed

  12. Properties and Planned Use of the Intense THz Radiation from ELBE at Dresden-Rossendorf.

    Science.gov (United States)

    Fahmy, K; Furlinski, G; Gippner, P; Grosse, E; Piest, H; Seidel, W; Sczepan, M; Wohlfarth, D; Wolf, A; Wuensch, R

    2003-06-01

    The radiation source ELBE atDresden-Rossendorf is centered around asuperconducting ELectron accelerator ofhigh Brilliance and low Emittance (ELBE) which produces electronbeams up to 40 MeV. This new facility delivers secondary radiation of differentkinds. Special emphasis will be given tothe production of intense THz radiationfrom its Free-Electron Lasers (FEL). This radiation will be usedfor various research activities including the life sciences. Two additionalfemtosecond Ti:sapphire laser systems allowto exploit different methods of THzgeneration for such investigations.

  13. Quantum properties of the radiation emitted by a conductor in the Coulomb blockade regime

    Science.gov (United States)

    Mora, C.; Altimiras, C.; Joyez, P.; Portier, F.

    2017-03-01

    We present an input-output formalism describing a tunnel junction strongly coupled to its electromagnetic environment. We exploit it in order to investigate the dynamics of the radiation being emitted and scattered by the junction. We find that the nonlinearity imprinted in the electronic transport by a properly designed environment generates strongly squeezed radiation. Our results show that the interaction between a quantum conductor and electromagnetic fields can be exploited as a resource to design simple sources of nonclassical radiation.

  14. Properties of the third harmonic of the radiation from self-amplified spontaneous emission free electron laser

    Directory of Open Access Journals (Sweden)

    E. L. Saldin

    2006-03-01

    Full Text Available Recent theoretical and experimental studies have shown that the self-amplified spontaneous emission free-electron laser (SASE FEL with a planar undulator holds a potential for generation of relatively strong coherent radiation at the third harmonic of the fundamental frequency. Here we present a detailed study of the nonlinear harmonic generation in the SASE FEL obtained with a time-dependent FEL simulation code. Using similarity techniques we present universal dependencies for temporal, spectral, and statistical properties of the odd harmonics of the radiation from SASE FEL. In particular, we derived universal formulas for radiation power of the odd harmonics at saturation. It was also found that coherence time at saturation falls inversely proportional to the harmonic number, and relative spectrum bandwidth remains constant with the harmonic number.

  15. Coherence properties and diagnostics of betatron radiation emitted by an externally-injected electron beam propagating in a plasma channel

    Energy Technology Data Exchange (ETDEWEB)

    Paroli, B., E-mail: bruno.paroli@unimi.it [Dipartimento di Fisica, Universitá degli Studi di Milano and INFN Sezione di Milano, via G. Celoria, 16, 20133 Milano (Italy); Chiadroni, E.; Ferrario, M. [INFN-LNF, via E. Fermi, 00044 Frascati (Italy); Mostacci, A. [“La Sapienza” University, SBAI Department, via A. Scarpa 14, 00161 Rome (Italy); INFN-LNF, via E. Fermi, 00044 Frascati (Italy); Petrillo, V.; Potenza, M.A.C.; Rossi, A.R.; Serafini, L. [Dipartimento di Fisica, Universitá degli Studi di Milano and INFN Sezione di Milano, via G. Celoria, 16, 20133 Milano (Italy)

    2015-07-15

    A 3-dimensional time-domain simulation of X-ray produced by a laser wakefield accelerated electron beam was performed in order to know its properties like intensity, spectrum, divergence and coherence. Particular attention was paid to the coherence around the acceleration axis. The broad spectrum of betatron radiation (1–10 keV) leads to a short coherence length. Nevertheless we observe that under particular detection condition the spatial coherence has a characteristic enlargement. We give a simplified interpretation of this effect in terms of phase shift of the electric field on a virtual detector. Moreover we describe a near field scattering technique to characterize the betatron radiation. This diagnostics will be used to map the transverse spatio-temporal coherence of X-ray radiation in the laser wakefield accelerator under development at Frascati National Laboratories (LNF)

  16. Coherence properties and diagnostics of betatron radiation emitted by an externally-injected electron beam propagating in a plasma channel

    Science.gov (United States)

    Paroli, B.; Chiadroni, E.; Ferrario, M.; Mostacci, A.; Petrillo, V.; Potenza, M. A. C.; Rossi, A. R.; Serafini, L.

    2015-07-01

    A 3-dimensional time-domain simulation of X-ray produced by a laser wakefield accelerated electron beam was performed in order to know its properties like intensity, spectrum, divergence and coherence. Particular attention was paid to the coherence around the acceleration axis. The broad spectrum of betatron radiation (1-10 keV) leads to a short coherence length. Nevertheless we observe that under particular detection condition the spatial coherence has a characteristic enlargement. We give a simplified interpretation of this effect in terms of phase shift of the electric field on a virtual detector. Moreover we describe a near field scattering technique to characterize the betatron radiation. This diagnostics will be used to map the transverse spatio-temporal coherence of X-ray radiation in the laser wakefield accelerator under development at Frascati National Laboratories (LNF).

  17. Impact of the ice phase on a mesoscale convective system: Implication of cloud parameterization and cloud radiative properties

    Energy Technology Data Exchange (ETDEWEB)

    Chin, H.N.S.; Bradley, M.M.; Molenkamp, C.R.; Grant, K.E.; Chuang, C.

    1991-08-01

    This study attempts to provide further understanding of the effect of the ice phase on cloud ensemble features which are useful for improving GCM cumulus parameterization. In addition, cloud model results are used to diagnose the radiative properties of anvils in order to assess cloud/radiation interaction and its feedback on the larger-scale climate for the future work. The heat, moisture and mass budget analyses of a simulated squall line system indicate that, at least for this type of system, the inclusion of the ice phase in the microphysics does not considerably change the net cloud heating and drying effects and the feedback on the large-scale motion. Nonetheless, its impact on the radiative properties of clouds significantly influences not only the squall line system itself, but also the larger-scale circulation due to the favorable stratification for long-lasting anvil clouds. The water budget suggests a simple methodology to parameterize the microphysical effect without considering it as a model physics module. Further application of the water budget might also be used to parameterize the cloud transport of condensates in the anvil cloud region, which allows the GCM columns to interact with each other. The findings of this study suggest that the ice phase could be ignored in the cloud parameterization in order to save significant amounts of computational resources and to simplify the model physics. More scientific effort should, however, be focused on the effect of the ice phase to further explore cloud feedback on the large-scale climate through the radiative process. The cloud/radiation interaction and its feedback on the larger-scale climate will be addressed in a companion study by coupling the radiative transfer model with the cloud model. 19 refs., 13 figs.

  18. VNIR, MWIR, and LWIR source assemblies for optical quality testing and spectro-radiometric calibration of earth observation satellites

    Science.gov (United States)

    Compain, Eric; Maquet, Philippe; Leblay, Pierrick; Gavaud, Eric; Marque, Julien; Glastre, Wilfried; Cortese, Maxime; Sugranes, Pierre; Gaillac, Stephanie; Potheau, Hervé

    2015-09-01

    This document presents several original OGSEs, Optical Ground Support Equipment, specifically designed and realized for the optical testing and calibration of earth observation satellites operating in a large spectral band from 0.4μm to 14.7μm. This work has been mainly supported by recent development dedicated to MTG, Meteosat Third Generation, the ESA next generation of meteorological satellites. The improved measurement capabilities of this new satellite generation has generated new challenging requirements for the associated optical test equipments. These improvements, based on design and component innovation will be illustrated for the MOTA, the GICS and the DEA OGSEs. MOTA and GICS are dedicated to the AIT, Assembly Integration and Test, of FCI, the Flexible Combined Imager of the imaging satellite MTG-I. DEA OGSE is dedicated to the AIT of the DEA, Detection Electronics Assembly, which is part of IRS instrument, an IR sounder part of MTG-S satellite. From an architectural point of view, the presented original designs enable to run many optical tests with a single system thanks to a limited configuration effort. Main measurement capabilities are optical quality testing (MTF based mainly on KEF measurement), Line of Sight (LoS) stability measurement, straylight analyses, VNIR-MWIR-LWIR focal plane array co-registration, and broadband large dynamic spectro-radiometric calibration. Depending on the AIT phase of the satellite, these source assemblies are operated at atmospheric pressure or under secondary vacuum. In operation, they are associated with an opto-mechanical projection system that enables to conjugate the image of the source assembly with the focal plane of the satellite instruments. These conjugation systems are usually based on high resolution, broadband collimator, and are optionally mounted on hexapod to address the entire field of instruments.

  19. Influence of porosity on electrical properties of low-k dielectrics irradiated with vacuum-ultraviolet radiation

    Science.gov (United States)

    Choudhury, F. A.; Nguyen, H. M.; Baklanov, M. R.; de Marneffe, J. F.; Li, W.; Pei, D.; Benjamin, D. I.; Zheng, H.; King, S. W.; Lin, Y.-H.; Fung, H.-S.; Chen, C.-C.; Nishi, Y.; Shohet, J. L.

    2016-09-01

    During plasma processing, low-k dielectrics are exposed to high levels of vacuum ultraviolet (VUV) radiation emitted from the plasma. The porous structure of these materials makes them more sensitive to modification because of their low density and consequently deep penetration of active species into the film. Here, we investigate the changes to electrical properties of porous low-k dielectrics as a function of porosity after VUV irradiation. Organosilicate low-k films of porosities between 30% and 50% were exposed to synchrotron VUV radiation at 8 eV with a fluence of approximately 5 × 1014 photons/cm2. Capacitance-voltage measurements showed an increase in the dielectric constant along with a flat-band voltage shift. FTIR results show methyl depletion as well as water uptake after VUV treatment. These show that deterioration of the electrical properties after VUV exposure and the degree of damage are found to be higher for the more porous films.

  20. Pattern scaling effect on the radiative properties of wafer’s surface

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    This paper presents a parametric study of the radiative properties of patterned wafers with a polysilicon gate array on the Si substrate, considering the effect of wavelength and polarization. The finite-difference time-domain (FDTD) method was employed to examine the pattern scaling effect on the spectral absorptance via numerical solutions of the Maxwell’s equations. The effective medium theory (EMT) was also used to help explain the absorptance predictions. While the gate sizes are very small compared to wavelength, the results show rather unusual phenomena. The absorptance calculated by EMT is in agreement with FDTD in the cases with small gate and period sizes. With the increase of period and decrease of the ratio of the gate width to the grating period, both EMT and FDTD results for the TM (transverse magnetic) mode approach to pure silicon since the grating effect diminishes. However, the error of EMT results for the TE mode in some cases becomes considerable due to the limitation of EMT, which requires the period to be significantly smaller than the wavelength. Besides, the TE (transverse electric) absorptance curve separates from that of plain Si when the wavelength equals the grating period, this is because the gate can interact with its neighbering region by diffraction and the diffraction effects are weak, when the wavelength is small. The peak absorptance can be attributed to the thin film effect. It shows that a slight increase in the gate height can drastically increase the absorptance and the increased gate height shifts the peak absorptance to longer wavelength due to the increase of optical path length in the effective thin film. This work is of great importance for optimization of advanced annealing techniques in semiconductor manufacturing.

  1. Characterisation of Conformational and Ligand Binding Properties of Membrane Proteins Using Synchrotron Radiation Circular Dichroism (SRCD).

    Science.gov (United States)

    Hussain, Rohanah; Siligardi, Giuliano

    Membrane proteins are notoriously difficult to crystallise for use in X-ray crystallographic structural determination, or too complex for NMR structural studies. Circular dichroism (CD) is a fast and relatively easy spectroscopic technique to study protein conformational behaviour in solution. The advantage of synchrotron radiation circular dichroism (SRCD) measured with synchrotron beamlines compared to the CD from benchtop instruments is the extended spectral far-UV region that increases the accuracy of secondary structure estimations, in particular under high ionic strength conditions. Membrane proteins are often available in small quantities, and for this SRCD measured at the Diamond B23 beamline has successfully facilitated molecular recognition studies. This was done by probing the local tertiary structure of aromatic amino acid residues upon addition of chiral or non-chiral ligands using long pathlength cells (1-5 cm) of small volume capacity (70 μl-350 μl). In this chapter we describe the use of SRCD to qualitatively and quantitatively screen ligand binding interactions (exemplified by Sbma, Ace1 and FsrC proteins); to distinguish between functionally similar drugs that exhibit different mechanisms of action towards membrane proteins (exemplified by FsrC); and to identify suitable detergent conditions to observe membrane protein-ligand interactions using stabilised proteins (exemplified by inositol transporters) as well as the stability of membrane proteins (exemplified by GalP, Ace1). The importance of the in solution characterisation of the conformational behaviour and ligand binding properties of proteins in both far- andnear-UV regions and the use of high-throughput CD (HT-CD) using 96- and 384-well multiplates to study the folding effects in various protein crystallisation buffers are also discussed.

  2. The Influence of Sea Ice on Arctic Low Cloud Properties and Radiative Effects

    Science.gov (United States)

    Taylor, Patrick C.

    2015-01-01

    The Arctic is one of the most climatically sensitive regions of the Earth. Climate models robustly project the Arctic to warm 2-3 times faster than the global mean surface temperature, termed polar warming amplification (PWA), but also display the widest range of surface temperature projections in this region. The response of the Arctic to increased CO2 modulates the response in tropical and extra-tropical regions through teleconnections in the atmospheric circulation. An increased frequency of extreme precipitation events in the northern mid-latitudes, for example, has been linked to the change in the background equator-to-pole temperature gradient implied by PWA. Understanding the Arctic climate system is therefore important for predicting global climate change. The ice albedo feedback is the primary mechanism driving PWA, however cloud and dynamical feedbacks significantly contribute. These feedback mechanisms, however, do not operate independently. How do clouds respond to variations in sea ice? This critical question is addressed by combining sea ice, cloud, and radiation observations from satellites, including CERES, CloudSAT, CALIPSO, MODIS, and microwave radiometers, to investigate sea ice-cloud interactions at the interannual timescale in the Arctic. Cloud characteristics are strongly tied to the atmospheric dynamic and thermodynamic state. Therefore, the sensitivity of Arctic cloud characteristics, vertical distribution and optical properties, to sea ice anomalies is computed within atmospheric dynamic and thermodynamic regimes. Results indicate that the cloud response to changes in sea ice concentration differs significantly between atmospheric state regimes. This suggests that (1) the atmospheric dynamic and thermodynamic characteristics and (2) the characteristics of the marginal ice zone are important for determining the seasonal forcing by cloud on sea ice variability.

  3. Characterization of the radiation shielding properties of US and Russian EVA suits using passive detectors

    Energy Technology Data Exchange (ETDEWEB)

    Benton, E.R. [Eril Research, Inc., Stillwater, OK 74074-1541 (United States)]. E-mail: erilresearch@gmail.com; Benton, E.V. [Physics Department, University of San Francisco, San Francisco, CA 94117-1080 (United States); Frank, A.L. [Physics Department, University of San Francisco, San Francisco, CA 94117-1080 (United States); Moyers, M.F. [Department of Radiation Medicine, Loma Linda University, Loma Linda, CA 92354 (United States)

    2006-10-15

    Radiation measurements using passive detectors were carried out to assess the shielding properties of the US Extravehicular Mobility Unit (EMU) space suit and the Russian Orlan-M suit during irradiations of the suits and a tissue-equivalent phantom by monoenergetic proton and electron beams at the Loma Linda University Medical Center (LLUMC). During irradiations of 6 MeV electrons and 60 MeV protons, absorbed dose as a function of depth was measured using thermoluminescent detector (TLD) exposed behind swatches of the two suit materials and inside the two extravehicular activity (EVA) helmets. Considerable reduction in electron dose was measured behind all suit materials on exposure to 6 MeV electrons. Slowing of the proton beam in the suit materials led to an increase in dose measured on exposure to 60 MeV protons. During 232 MeV proton irradiations, measurements were made with TLD and CR-39 plastic nuclear track detector (PNTD) at five organ locations inside a tissue-equivalent phantom, exposed both with and without the two EVA suits. The EVA helmets produced a 13% to 27% reduction in total absorbed dose and a 0% to 25% reduction in dose equivalent when compared to measurements made in the phantom head alone. Differences in absorbed dose and dose equivalent between the suit and non-suit irradiations for the lower portions of the two EVA suits tended to be smaller. Proton-induced target fragmentation was found to be a significant source of increased dose equivalent, especially within the two EVA helmets, and average quality factor inside the EMU and Orlan-M helmets was 2% to 14% greater than that measured in the bare phantom head.

  4. Influence of heterogeneous freezing on the microphysical and radiative properties of orographic cirrus clouds

    Directory of Open Access Journals (Sweden)

    H. Joos

    2013-07-01

    Full Text Available The influence of heterogeneous freezing on the microphysical and optical properties of orographic cirrus clouds has been simulated with the cloud resolving model EULAG. Idealized simulations with different concentrations of ice nuclei (IN in a dynamically dominated regime with high vertical velocities have been performed. Furthermore the temperature under which the cloud forms as well as the critical supersaturation which is needed for the initiation of heterogenoues freezing have been varied. The short wave, long wave and net cloud forcing has been calculated under the assumption that the clouds form between 06:00 and 12:00 LT or between 12:00 and 18:00 LT, respectively. In general it can be seen that the onset of homogeneous freezing is shifted in time depending on the IN concentration as part of the available water vapor is depleted before the critical threshold for homogeneous freezing is reached. Although the high vertical velocities in an orographic gravity wave lead to a strong adiabatic cooling followed by high ice supersaturations, a small number concentration of IN in the order of 5 L−1 is already able to strongly decrease the simulated ice crystal number burden (ICNB, ice water path (IWP and optical depth of the cloud. In general, the ICNB, IWP and optical depth strongly decrease when the IN concentrations are increased from 0 to 50 L−1. The absolute values of the short wave, long wave and net cloud forcing are also reduced with increasing IN concentrations. If a cloud produces a net warming or cooling depends on the IN concentration, the temperature and the time of day at which the cloud forms. The clouds that form between 06:00 and 12:00 LT are mainly cooling whereas the clouds with the same microphysical properties can lead to a warming when they form between 12:00 and 18:00 LT. In order to predict the radiative forcing of cirrus clouds it is therefore necessary to take the correct dynamical and thermodynamical processes as

  5. 3D Gray Radiative Properties of Accretion Shocks in Young Stellar Objects

    Directory of Open Access Journals (Sweden)

    Ibgui L.

    2014-01-01

    Full Text Available We address the problem of the contribution of radiation to the structure and dynamics of accretion shocks on Young Stellar Objects. Solving the 3D RTE (radiative transfer equation under our “gray LTE approach”, i.e., using appropriate mean opacities computed in local thermodynamic equilibrium, we post-process the 3D MHD (magnetohydrodynamic structure of an accretion stream impacting the stellar chromosphere. We find a radiation flux of ten orders of magnitude larger than the accreting energy rate, which is due to a large overestimation of the radiative cooling. A gray LTE radiative transfer approximation is therefore not consistent with the given MHD structure of the shock. Further investigations are required to clarify the role of radiation, by relaxing both the gray and LTE approximations in RHD (radiation hydrodynamics simulations. Post-processing the obtained structures through the resolution of the non-LTE monochromatic RTE will provide reference radiation quantities against which RHD approximate solutions will be compared.

  6. Statistical properties of the radiation from SASE FEL operating in a post-saturation regime with and without undulator tapering

    CERN Document Server

    Schneidmiller, E A

    2015-01-01

    We describe statistical and coherence properties of the radiation from x-ray free electron lasers (XFEL) operating in the post-saturation regime. We consider practical case of the SASE3 FEL at the European XFEL. We perform comparison of the main characteristics of the X-ray FEL operating in the post-saturation regime with and without undulator tapering: efficiency, coherence time and degree of transverse coherence.

  7. Performance of 12- μm- to 15- μm-Pitch MWIR and LWIR HgCdTe FPAs at Elevated Temperatures

    Science.gov (United States)

    Strong, Roger L.; Kinch, Michael A.; Armstrong, John M.

    2013-11-01

    Infrared (IR) focal-plane arrays (FPAs) with higher operating temperatures and smaller pitches enable reduced size, weight, and power in infrared systems. We have characterized a large number of medium- and long-wavelength IR (MWIR and LWIR) FPAs as a function of temperature and cutoff wavelength to determine the impact of these parameters on their performance. The 77-K cutoff wavelength range for the MWIR arrays was 5.0 μm to 5.6 μm, and 8.6 μm to 11.3 μm for the LWIR. The dark currents in DRS's high-density vertically integrated photodiode (HDVIP)® FPAs (based on a front-side- illuminated, via-interconnected, cylindrical-geometry N+/N/P architecture) are dominated by Auger-7 recombination from 120 K to 200 K for the MWIR and 70 K to 100 K for the LWIR. In these temperature ranges the FPA operability is generally limited not by dark current defects but by noise defects. Pixels with high 1/ f noise should produce a tail in the root-mean-square (rms) noise distribution. We have found that the skewness of the rms noise distribution is the simplest measure of an array's 1/ f noise, and that the rms noise skewness typically shows little variation over these temperature ranges. The temperature dependence of the defect counts in normal arrays (wet etched prior to CdTe interdiffusion) increases as n i, while nonstandard arrays (ion milled or plasma etched prior to CdTe interdiffusion) can have high 1/ f noise and defect counts that vary as n {i/2}. Our models indicate that, if the dominant dark current is due to diffusion, then the 1/ f noise varies as n {i/2}, whereas if depletion current dominates, then the 1/ f noise varies as n i. Systemic 1/ f noise is not an issue for DRS's standard MWIR FPAs at 110 K to 160 K, or for standard LWIR FPAs at 77 K to 100 K.

  8. Influence of high-dose gamma radiation and particle size on antioxidant properties of Maize ( Zea mays L.) flour

    Energy Technology Data Exchange (ETDEWEB)

    Nawaz, Haq; Shad, Muhammad Aslam; Rehman, Tanzila; Ramzan, Ayesha, E-mail: haqnawaz@bzu.edu.pk [Bahauddin Zakariya University, Multan (Pakistan)

    2016-10-15

    Influence of high-dose gamma radiation and particle size on antioxidant properties of maize (Zea mays L.) flour was studied using response surface methodology. A central composite design based on three levels of each of particle size, in terms of mesh number (40, 60 and 80 meshes), and gamma radiation dose (25, 50 and 75 kGy) was constructed. A statistically significant dose-dependent decrease (p<0.05) in antioxidant properties of gamma irradiated flour was observed. However, an increase in the mesh number (decrease in particle size of flour) resulted in an increase in antioxidant properties. The optimum level of radiation dose to achieve maximum value of responses was found to be 50 kGy for Trolox equivalent total antioxidant activity (TETAOA), 25 kGy for iron chelating ability (ICA), 25 kGy for reducing power (RP) and 75 kGy for linoleic acid reduction capacity (LARC). However, the optimum level of mesh number to achieve desired levels of TETAOA, ICA, RP and LARC was found to be 80 meshes. (author)

  9. Urban aerosol properties, their radiative effects and the verification of different satellite retrievals of urban aerosol pollution

    Science.gov (United States)

    Chubarova, Nataly; Sviridenkov, Mikhail; Kopeikin, Vladimir; Emilenko, Alexander; Verichev, Konstantin; Skorokhod, Andrei; Semutnikova, Evgenia

    2013-04-01

    The effects of urban pollution on different aerosol properties and their year-to-year-changes in various atmospheric conditions were studied according to long-term simultaneous measurements by the collocated AERONET CIMEL sun/sky photometers in Moscow (large megacity) and at Zvenigorod (nearby clean area) for 2006-2012 year period. Additional measurements of PM10 and PM2.5, as well as soot content observations were used for evaluating the effects of local urban sources and their influence on columnar aerosol properties (single scattering albedo, aerosol optical thickness, etc.) and, hence, on radiative properties of aerosol. We discuss the results of the comparisons between RT modeling and high quality ground-based radiative measurements, which provide validation of the obtained urban radiative effects for different aerosols in clear-sky conditions. Special attention was paid to testing the retrievals of several aerosol parameters (AOT, single scattering albedo, Angstrom exponent, etc) over the urban area and the detection of the urban aerosol pollution by different satellite instruments (MISR, MODIS, SEAWIFS, OMI) against the data of collocated AERONET CIMEL sun/sky photometers in different atmospheric conditions over snow and snow-free surfaces.

  10. Differences in rates of decrease of environmental radiation dose rates by ground surface property in Fukushima City after the Fukushima Daiichi nuclear power plant accident.

    Science.gov (United States)

    Kakamu, Takeyasu; Kanda, Hideyuki; Tsuji, Masayoshi; Kobayashi, Daisuke; Miyake, Masao; Hayakawa, Takehito; Katsuda, Shin-ichiro; Mori, Yayoi; Okouchi, Toshiyasu; Hazama, Akihiro; Fukushima, Tetsuhito

    2013-01-01

    After the Great East Japan Earthquake on 11 March 2011, the environmental radiation dose in Fukushima City increased. On 11 April, 1 mo after the earthquake, the environmental radiation dose rate at various surfaces in the same area differed greatly by surface property. Environmental radiation measurements continue in order to determine the estimated time to 50% reduction in environmental radiation dose rates by surface property in order to make suggestions for decontamination in Fukushima. The measurements were carried out from 11 April to 11 November 2011. Forty-eight (48) measurement points were selected, including four kinds of ground surface properties: grass (13), soil (5), artificial turf (7), and asphalt (23). Environmental radiation dose rate was measured at heights of 100 cm above the ground surface. Time to 50% reduction of environmental radiation dose rates was estimated for each ground surface property. Radiation dose rates on 11 November had decreased significantly compared with those on 11 April for all surface properties. Artificial turf showed the longest time to 50% reduction (544.32 d, standard error: 96.86), and soil showed the shortest (213.20 d, standard error: 35.88). The authors found the environmental radiation dose rate on artificial materials to have a longer 50% reduction time than that on natural materials. These results contribute to determining an order of priority for decontamination after nuclear disasters.

  11. Influence of electromagnetic radiation produced by mobile phone on some biophysical blood properties in rats.

    Science.gov (United States)

    El-Bediwi, Abu Bakr; Saad, Mohamed; El-kott, Attall F; Eid, Eman

    2013-04-01

    Effects of electromagnetic radiation produced by mobile phone on blood viscosity, plasma viscosity, hemolysis, Osmotic fragility, and blood components of rats have been investigated. Experimental results show that there are significant change on blood components and its viscosity which affects on a blood circulation due to many body problems. Red blood cells, White blood cells, and Platelets are broken after exposure to electromagnetic radiation produced by mobile phone. Also blood viscosity and plasma viscosity values are increased but Osmotic fragility value decreased after exposure to electromagnetic radiation produced by mobile phone.

  12. Relationships Between Ice Cloud Properties and Radiative Effects from A-Train Observations and Global Climate Models

    Science.gov (United States)

    Berry, B. J.; Mace, G. G.

    2014-12-01

    Using data from the A-Train satellites, we investigate the distribution of clouds and their microphysical and radiative properties in Southeast Asia during the summer monsoon. We find an approximate balance in the top of the atmosphere (TOA) cloud radiative effect, which is largely due to commonly occurring cirrus layers that warm the atmosphere, and less frequent deep layer clouds, which produce a strong cooling at the surface. The distribution of cloud ice water path (IWP) in cirrus layers, obtained from the 2C-ICE CloudSat data product, is highly skewed with a mean value of 170 g m-2 and a median of 16 g m-2. We evaluate the fraction of the total IWP observed by CloudSat and CALIPSO individually and find that both instruments are necessary for describing the overall IWP statistics and particularly the values that are most important to cirrus radiative impact. In examining how cirrus cloud radiative effects at the TOA vary as a function of IWP, we find that cirrus with IWP less than 200 g m-2 produce a net warming. Weighting the distribution of radiative effect by the frequency of occurrence of IWP values, we find that cirrus with IWP around 20 g m-2 contribute most to heating at the TOA. We conclude that the mean IWP is a poor diagnostic of radiative impact. We suggest that climate model intercomparisons with data should focus on the median IWP because that statistic is more descriptive of the cirrus that contribute most to the radiative impacts of tropical ice clouds. Given these findings, we use the A-Train observations to address the issues of IWP occurrence and high cloud forcing in a global climate model (GCM). Our goal is to determine whether the clouds that heat the upper troposphere in the model are the same genre of clouds that heat the upper troposphere in the real atmosphere. First, we define a cloud radiative kernel that's a function of IWP to determine whether the modeled ice clouds produce similar shortwave and longwave radiative effects at the TOA

  13. Investigation on seasonal variations of aerosol properties and its influence on radiative effect over an urban location in central India

    Science.gov (United States)

    Jose, Subin; Gharai, Biswadip; Niranjan, K.; Rao, P. V. N.

    2016-05-01

    Aerosol plays an important role in modulating solar radiation, which are of great concern in perspective of regional climate change. The study analysed the physical and optical properties of aerosols over an urban area and estimated radiative effect using three years in-situ data from sunphotometer, aethalometer and nephelometer as input to radiative transfer model. Aerosols properties indicate the dominance of fine mode aerosols over the study area. However presence of coarse mode aerosols is also found during pre-monsoon [March-April-May]. Daily mean aerosol optical depth showed a minimum during winter [Dec-Jan-Feb] (0.45-0.52) and a maximum during pre-monsoon (0.6-0.7), while single scattering albedo (ω) attains its maximum (0.78 ± 0.05) in winter and minimum (0.67 ± 0.06) during pre-monsoon and asymmetry factor varied in the range between 0.48 ± 0.02 to 0.53 ± 0.04. Episodic events of dust storm and biomass burning are identified by analyzing intrinsic aerosol optical properties like scattering Ångström exponent (SAE) and absorption Ångström exponent (AAE) during the study periods and it has been observed that during dust storm events ω is lower (˜0.77) than that of during biomass burning (˜0.81). The aerosol direct radiative effect at top of the atmosphere during winter is -11.72 ± 3.5 Wm-2, while during pre-monsoon; it is -5.5 ± 2.5 Wm-2, which can be due to observed lower values of ω during pre-monsoon. A large positive enhancement of atmospheric effect of ˜50.53 Wm-2 is observed during pre-monsoon compared to winter. Due to high aerosol loading in pre-monsoon, a twofold negative surface forcing is also observed in comparison to winter.

  14. A new parameterization for ice cloud optical properties used in BCC-RAD and its radiative impact

    Science.gov (United States)

    Zhang, Hua; Chen, Qi; Xie, Bing

    2015-01-01

    A new parameterization of the solar and infrared optical properties of ice clouds that considers the multiple habits of ice particles was developed on the basis of a prescribed dataset. First, the fitting formulae of the bulk extinction coefficient, single-scatter albedo, asymmetry factor, and δ-function forward-peak factor at the given 65 wavelengths as a function of effective radius were created for common scenarios, which consider a greater number of wavelengths and are more accurate than those used previously. Then, the band-averaged volume extinction and absorption coefficients, asymmetry factor and forward-peak factor of ice cloud were derived for the BCC-RAD (Beijing Climate Center radiative transfer model) using a parameter reference table. Finally, the newly developed and the original schemes in the BCC-RAD and the commonly used Fu Scheme of ice cloud were all applied to the BCC-RAD. Their influences on radiation calculations were compared using the mid-latitude summer atmospheric profile with ice clouds under no-aerosol conditions, and produced a maximum difference of approximately 30.0 W/m2 for the radiative flux, and 4.0 K/d for the heating rate. Additionally, a sensitivity test was performed to investigate the impact of the ice crystal density on radiation calculations using the three schemes. The results showed that the maximum difference was 68.1 W/m2 for the shortwave downward radiative flux (for the case of perpendicular solar insolation), and 4.2 K/d for the longwave heating rate, indicating that the ice crystal density exerts a significant effect on radiation calculations for a cloudy atmosphere.

  15. Simple Models of the Spatial Distribution of Cloud Radiative Properties for Remote Sensing Studies

    Science.gov (United States)

    2004-01-01

    This project aimed to assess the degree to which estimates of three-dimensional cloud structure can be inferred from a time series of profiles obtained at a point. The work was motivated by the desire to understand the extent to which high-frequency profiles of the atmosphere (e.g. ARM data streams) can be used to assess the magnitude of non-plane parallel transfer of radiation in thc atmosphere. We accomplished this by performing an observing system simulation using a large-eddy simulation and a Monte Carlo radiative transfer model. We define the 3D effect as the part of the radiative transfer that isn't captured by one-dimensional radiative transfer calculations. We assess the magnitude of the 3D effect in small cumulus clouds by using a fine-scale cloud model to simulate many hours of cloudiness over a continental site. We then use a Monte Carlo radiative transfer model to compute the broadband shortwave fluxes at the surface twice, once using the complete three-dimensional radiative transfer F(sup 3D), and once using the ICA F (sup ICA); the difference between them is the 3D effect given.

  16. Shielding properties of lead-free protective clothing and their impact on radiation doses.

    Science.gov (United States)

    Schlattl, Helmut; Zankl, Maria; Eder, Heinrich; Hoeschen, Christoph

    2007-11-01

    The shielding properties of two different lead-free materials-tin and a compound of 80% tin and 20% bismuth-for protective clothing are compared with those of lead for three typical x-ray spectra generated at tube voltages of 60, 75, and 120 kV. Three different quantities were used to compare the shielding capability of the different materials: (1) Air-kerma attenuation factors in narrow-beam geometry, (2) air-kerma attenuation factors in broad-beam geometry, and (3) ratios of organ and effective doses in the human body for a whole-body irradiation with a parallel beam directed frontally at the body. The thicknesses of tin (0.45 mm) and the tin/bismuth compound (0.41 mm) to be compared against lead correspond to a lead equivalence value of 0.35 mm for the 75 kV spectrum. The narrow-beam attenuation factors for 0.45 mm tin are 54% and 32% lower than those for 0.35 mm lead for 60 and 120 kV; those for 0.41 mm tin/bismuth are 12% and 32% lower, respectively. The decrease of the broad-beam air-kerma attenuation factors compared to lead is 74%, 46%, and 41% for tin and 42%, 26%, and 33% for tin/bismuth and the spectra at 60, 75, and 120 kV, respectively. Therefore, it is recommended that the characterization of the shielding potential of a material should be done by measurements in broad-beam geometry. Since the secondary radiation that is mainly responsible for the shielding reduction in broad-beam geometry is of low penetrability, only more superficially located organs receive significantly enhanced doses. The increase for the dose to the glandular breast tissue (female) compared to being shielded by lead is 143%, 37%, and 45% when shielded by tin, and 35%, 15%, and 39% when shielded by tin/bismuth for 60, 75, and 120 kV, respectively. The effective dose rises by 60%, 6%, and 38% for tin, and 14%, 3% and, 35% for tin/bismuth shielding, respectively.

  17. Black carbon aerosols and their radiative properties in the Pearl River Delta region

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The climatic and environmental effects of atmospheric aerosols are a hot topic in global science community, and radiative properties of the aerosols are one of the important parameters in assessing climatic change. Here we studied the black carbon concentration and absorption coefficient measured with aethalometers, scattering coefficient measured with nephelometers, and single scattering albedo derived at an atmospheric composition watch station in Guangzhou from 2004 to 2007. Our main results are as follows. The data of black carbon concentration and absorption coefficients measured with instruments cannot be directly used until they are measured in parallel with internationally accepted instruments for comparison, calibration, and reduction. After evaluation of the data, the result shows that the monthly mean of BC concentration varies 3.1―14.8 μg·m-3 and the concentration decreases by about 1 μg·m-3 in average over the four years; It is higher in the dry season with a multi-year mean of 8.9 μg/m3 and lower in the rainy season with a multi-year mean of 8.0 μg·m-3; The extreme maximum of monthly mean concentration occurred in December 2004 and extreme minimum in July 2007, and a 4-year mean is 8.4 μg·m-3. It is also shown that monthly mean scattering coefficient derived varies 129 -565 Mm-1, monthly mean absorption coefficient 32-139 Mm-1, and monthly mean single scattering albedo 0.71-0.91, with annual mean values of 0.80, 0.82, 0.79 and 0.84 for 2004, 2005, 2006 and 2007, respectively. Three instruments were used to take simultaneous measurements of BC in PM10, PM2.5, and PM1 and the results showed that PM2.5 took up about 90% of PM10 and PM1 accounted for about 68% of PM2.5, and BC aerosols are mainly present in fine particulates. The variability of BC concentrations is quite consistent between the Nancun station (141 m above sea level) and the Panyu station (13 m above sea level), which are 8 km apart from each other. The concentration in higher

  18. Black carbon aerosols and their radiative properties in the Pearl River Delta region

    Institute of Scientific and Technical Information of China (English)

    WU Dui; MAO JieTai; DENG XueJiao; TIE XueXi; ZHANG YuanHang; ZENG LiMin; LI Fei; TAN HaoBo; BI XueYan; HUANG XiaoYing; CHEN Jing; DENG Tao

    2009-01-01

    The climatic and environmental effects of atmospheric aerosols are a hot topic in global science community, and radiative properties of the aerosols are one of the important parameters in assessing climatic change. Here we studied the black carbon concentration and absorption coefficient measured with aethalometers, scattering coefficient measured with nephelometers, and single scattering albedo derived at an atmospheric composition watch station in Guangzhou from 2004 to 2007. Our main resuits are as follows. The data of black carbon concentration and absorption coefficients measured with instruments cannot be directly used until they are measured in parallel with internationally accepted instruments for comparison, calibration, and reduction. After evaluation of the data, the result shows that the monthly mean of BC concentration varies 3.1-14.8 pg. m-3 and the concentration decreases by about 1 μg. m-3 in average over the four years; It is higher in the dry season with a multi-year mean of monthly mean concentration occurred in December 2004 and extreme minimum in July 2007, end a 4-year mean is 8.4 pg. m-3. It is also shown that monthly mean scattering coefficient derived varies 129 -565 Mm-1, monthly mean absorption coefficient 32-139 Mm-1, and monthly mean single scattering albedo 0.71-0.91, with annual mean values of 0.80, 0.82, 0.79 and 0.84 for 2004, 2005, 2006 and 2007, respectively. Three instruments were used to take simultaneous measurements of BC in PM10, PM2.5, and PM1 and the results showed that PM2.5 took up about 90% of PM10 and PM1 accounted for about 66% of PM2.5, and BC aerosols are mainly present in fine particulates. The variability of BC concentrations is quite consistent between the Nancun station (141 m above sea level) and the Panyu station (13 m above sea level), which are 8 km apart from each other. The concentration in higher altitude station (Panyu) is consistently lower than the lower altitude station (Nancun), and the difference of

  19. Death of an Arctic Mixed Phase Cloud: How Changes in the Arctic Environment Influence Cloud Properties and Cloud Radiative Feedbacks

    Science.gov (United States)

    Roesler, E. L.; Posselt, D. J.

    2012-12-01

    Arctic mixed phase stratocumulus clouds exert an important influence on the radiative budget over the Arctic ocean and sea ice. Field programs and numerical experiments have shown the properties of these clouds to be sensitive to changes in the surface properties, thermodynamic environment, and aerosols. While it is clear that Arctic mixed-phase clouds respond to changes in the Arctic environment, uncertainty remains as to how climate warming will affect the cloud micro- and macrophysical properties. This is in no small part due to the fact that there are nonlinear interactions between changes in atmospheric and surface properties and changes in cloud characteristics. In this study, large-eddy simulations are performed of an arctic mixed phase cloud observed during the Indirect and Semi-Direct Aerosol Campaign. A parameter-space-filling uncertainty quantification technique is used to rigorously explore how simulated arctic mixed phase clouds respond to changes in the properties of the environment. Specifically, the cloud ice and aerosol concentration, surface sensible and latent heat fluxes, and large scale temperature, water vapor, and vertical motion are systematically changed, and the properties of the resulting clouds are examined. It is found that Arctic mixed phase clouds exhibit four characteristic behaviors: stability, growth, decay, and dissipation. Sets of environmental and surface properties that lead to the emergence of each type of behavior are presented, and the implications for the response of Arctic clouds to changes in climate are explored.

  20. A short review of radiation-induced raft-mediated graft copolymerization: A powerful combination for modifying the surface properties of polymers in a controlled manner

    Science.gov (United States)

    Barsbay, Murat; Güven, Olgun

    2009-12-01

    Surface grafting of polymeric materials is attracting increasing attention as it enables the preparation of new materials from known and commercially available polymers having desirable bulk properties such as thermal stability, elasticity, permeability, etc., in conjunction with advantageous newly tailored surface properties such as biocompatibility, biomimicry, adhesion, etc. Ionizing radiation, particularly γ radiation is one of the most powerful tools for preparing graft copolymers as it generates radicals on most substrates. With the advent of living free-radical polymerization techniques, application of γ radiation has been extended to a new era of grafting; grafting in a controlled manner to achieve surfaces with tailored and well-defined properties. This report presents the current use of γ radiation in living free-radical polymerization and highlights the use of both techniques together as a combination to present an advance in the ability to prepare surfaces with desired, tunable and well-defined properties.

  1. A short review of radiation-induced raft-mediated graft copolymerization: A powerful combination for modifying the surface properties of polymers in a controlled manner

    Energy Technology Data Exchange (ETDEWEB)

    Barsbay, Murat [Department of Chemistry, Hacettepe University, 06800 Beytepe, Ankara (Turkey)], E-mail: mbarsbay@hacettepe.edu.tr; Gueven, Olgun [Department of Chemistry, Hacettepe University, 06800 Beytepe, Ankara (Turkey)], E-mail: guven@hacettepe.edu.tr

    2009-12-15

    Surface grafting of polymeric materials is attracting increasing attention as it enables the preparation of new materials from known and commercially available polymers having desirable bulk properties such as thermal stability, elasticity, permeability, etc., in conjunction with advantageous newly tailored surface properties such as biocompatibility, biomimicry, adhesion, etc. Ionizing radiation, particularly {gamma} radiation is one of the most powerful tools for preparing graft copolymers as it generates radicals on most substrates. With the advent of living free-radical polymerization techniques, application of {gamma} radiation has been extended to a new era of grafting; grafting in a controlled manner to achieve surfaces with tailored and well-defined properties. This report presents the current use of {gamma} radiation in living free-radical polymerization and highlights the use of both techniques together as a combination to present an advance in the ability to prepare surfaces with desired, tunable and well-defined properties.

  2. Preparation and Properties of Smart Thermal Control and Radiation Protection Materials for Multi-functional Structure of Small Spacecraft

    Institute of Scientific and Technical Information of China (English)

    shijie Zhang; Xibin Cao; Yingqiang Luan; Xinxin Ma; Xiaohui Lin; Xianren Kong

    2011-01-01

    Considering the unique properties of small spacecraft, such as light weight, low power-consumption and high heat flux density, a new kind of lightweight boron carbide (B4C) radiation-protection coating material was proposed. New techniques for preparing LSMO thermal control coating and B4C radiation-protection coating were developed. The sample piece of multi-functional structure was manufactured by using the proposed materials, and a series of performance tests, such as thermal control and radiation-protection behaviors were evaluated. Test results show that: the emissivity of the multi-functional structure varies from 0.42 to 0.86 at 240 K to 353 K and the phase transition temperature is about 260 K. The electron radiation-protection ability of the multi-functional structure is 3.3 times better than that of Al material. The performance index of this multi-functional structure can meet the requirements for space application in on-board electronic equipment.

  3. Radiolytic formation of Fe3O4 nanoparticles: influence of radiation dose on structure and magnetic properties.

    Directory of Open Access Journals (Sweden)

    Alam Abedini

    Full Text Available Colloidal Fe3O4 nanoparticles were synthesized using a gamma-radiolysis method in an aqueous solution containing iron chloride in presence of polyvinyl alcohol and isopropanol as colloidal stabilizer and hydroxyl radical scavenger, respectively. Gamma irradiation was carried out in a 60Co gamma source chamber at different absorbed doses. Increasing the radiation dose above a certain critical dose (100 kGy leads to particle agglomeration enhancement, and this can influence the structure and crystallinity, and consequently the magnetic properties of the resultant particles. The optimal condition for formation of Fe3O4 nanoparticles with a uniform and narrow size distribution occurred at a dose of 100 kGy, as confirmed by X-ray diffractometry and transmission electron microscopy. A vibrating sample magnetometry study showed that, when radiation dose increased, the saturation and remanence magnetization decreased, whereas the coercivity and the remanence ratio increased. This magnetic behavior results from variations in crystallinity, surface effects, and particle size effects, which are all dependent on the radiation dose. In addition, Fourier transform infrared spectroscopy was performed to investigate the nature of the bonds formed between the polymer chains and the metal surface at different radiation doses.

  4. Electron-radiation effects on the ac and dc electrical properties and unpaired electron densities of three aerospace polymers

    Science.gov (United States)

    Long, Sheila Ann T.; Long, Edward R., Jr.; Ries, Heidi R.; Harries, Wynford L.

    1986-12-01

    The effects of gigarad-level total absorbed doses from 1-MeV electrons on the post-irradiation alternating-current (ac) and direct-current (dc) electrical properties and the unpaired electron densities have been studied for Kapton, Ultem, and Mylar. The unpaired electron densities (determined from electron paramagnetic resonance spectroscopy) and the dc electrical conductivities of the irradiated materials were monitored as functions of time following the exposures to determine their decay characteristics at room temperature. The elevated-temperature ac electrical dissipations of the Ultem and Mylar were affected by the radiation. The dc conductivity of the Kapton increased by five orders of magnitude, while the dc conductivities of the Ultem and Mylar increased by less than an order of magnitude, due to the radiation. The observed radiation-generated changes in the ac electrical dissipations are explained in terms of known radiation-generated changes in the molecular structures of the three materials. A preliminary model relating the dc electrical conductivity and the unpaired electron density in the Kapton is proposed.

  5. Electron-radiation effects on the ac and dc electrical properties and unpaired electron densities of three aerospace polymers

    Science.gov (United States)

    Long, Sheila Ann T.; Long, Edward R., Jr.; Ries, Heidi R.; Harries, Wynford L.

    1986-01-01

    The effects of gigarad-level total absorbed doses from 1-MeV electrons on the post-irradiation alternating-current (ac) and direct-current (dc) electrical properties and the unpaired electron densities have been studied for Kapton, Ultem, and Mylar. The unpaired electron densities (determined from electron paramagnetic resonance spectroscopy) and the dc electrical conductivities of the irradiated materials were monitored as functions of time following the exposures to determine their decay characteristics at room temperature. The elevated-temperature ac electrical dissipations of the Ultem and Mylar were affected by the radiation. The dc conductivity of the Kapton increased by five orders of magnitude, while the dc conductivities of the Ultem and Mylar increased by less than an order of magnitude, due to the radiation. The observed radiation-generated changes in the ac electrical dissipations are explained in terms of known radiation-generated changes in the molecular structures of the three materials. A preliminary model relating the dc electrical conductivity and the unpaired electron density in the Kapton is proposed.

  6. Simultaneous reconstruction of temperature distribution and radiative properties in participating media using a hybrid LSQR PSO algorithm

    Institute of Scientific and Technical Information of China (English)

    牛春洋; 齐宏; 黄兴; 阮立明; 王伟; 谈和平

    2015-01-01

    A hybrid least-square QR decomposition (LSQR)-particle swarm optimization (LSQR–PSO) algorithm was devel-oped to estimate the three-dimensional (3D) temperature distributions and absorption coefficients simultaneously. The outgoing radiative intensities at the boundary surface of the absorbing media were simulated by the line-of-sight (LOS) method, which served as the input for the inverse analysis. The retrieval results showed that the 3D temperature distribu-tions of the participating media with known radiative properties could be retrieved accurately using the LSQR algorithm, even with noisy data. For the participating media with unknown radiative properties, the 3D temperature distributions and absorption coefficients could be retrieved accurately using the LSQR–PSO algorithm even with measurement errors. It was also found that the temperature field could be estimated more accurately than the absorption coefficients. In order to gain insight into the effects on the accuracy of temperature distribution reconstruction, the selection of the detection direction and the angle between two detection directions was also analyzed.

  7. Structure, mechanical and tribological properties of radiation cross-linked ultrahigh molecular weight polyethylene and composite materials based on it

    Energy Technology Data Exchange (ETDEWEB)

    Tcherdyntsev, V.V., E-mail: vvch@misis.ru [National University of Science and Technology «MISiS», Leninsky Prospect, 4, Moscow, 119049 (Russian Federation); Kaloshkin, S.D.; Lunkova, A.A.; Musalitin, A.M. [National University of Science and Technology «MISiS», Leninsky Prospect, 4, Moscow, 119049 (Russian Federation); Danilov, V.D. [A.A. Blagonravov Institute of Mechanical Engineering RAS, ul. Bardina 4, Moscow, 117334 (Russian Federation); Borisova, Yu.V.; Boykov, A.A.; Sudarchikov, V.A. [National University of Science and Technology «MISiS», Leninsky Prospect, 4, Moscow, 119049 (Russian Federation)

    2014-02-15

    Highlights: • Effect of irradiation, oriented drawing, and filling on the structure and properties of UHMWPE was studied. • Radiation cross-linking leads to an increase in the melting temperature of UHMWPE. • The optimal irradiation dose is found to be 20 Mrad. • Strength of UHMWPE can be improved by a combination of irradiation, orientation, and filling with nanotubes. -- Abstract: The effect of irradiation with electrons, oriented drawing, and reinforcement with multi-walled carbon nanotubes (MWCNT) on the structure, physico-mechanical and tribological properties of ultrahigh molecular weight polyethylene (UHMWPE) is studied. It is shown that the radiation cross-linking leads to the melting temperature of UHMWPE nearly linear increases with the dose of radiation. The optimal irradiation dose with respect to the mechanical characteristics is found to be 20 Mrad. It is shown that the strength characteristics of UHMWPE can be improved most efficiently by a combination of irradiation, oriented drawing, and reinforcement with nanotubes, and the second and the third factors have a stronger effect than the first one. A combined effect of three factors enabled us to enhance the yield strength of material by almost four times without a detrimental effect on its plasticity.

  8. Radiation-induced graft polymerization of acrylamide: Reverse osmosis properties of polyethylene-g-poly(acrylamide) membrane

    Science.gov (United States)

    Dessouki, Ahmed M.; Hegazy, El-Sayed A.; El-Assy, Nasef B.; El-Boohy, Hussein A.

    A study has been made of some properties of the graft copolymer obtained by direct radiation grafting of acrylamide (AAm) onto low density polyethylene (LDPE) films. The swelling behaviour was investigated for the grafted and alkali-treated graft copolymer and it was found that this depends mainly on the amount of hydrophilic groups and also on the type of electrolytes (K- or Nasalts). salts). Some other properties of the graft copolymer films such as dimensional change wet and dry, electrical conductivity, and mechanical properties were studied. A trial has been made of such membrane for reverse osmosis desalination of saline water. The effect of operating time, degree of grafting, applied pressure and feed concentration on the water flux and salt rejection was determined.

  9. Effects of ionizing radiation on the antioxidant system of microscopic fungi with radioadaptive properties found in the Chernobyl exclusion zone.

    Science.gov (United States)

    Tugay, Tatyana I; Zheltonozhskaya, Marina V; Sadovnikov, Leonid V; Tugay, Andrei V; Farfán, Eduardo B

    2011-10-01

    Some microscopic fungi found in the area of the Chernobyl Exclusion Zone appear to have unique radioadaptive properties associated with their capability to respond positively to the effects of ionizing irradiation. On the one hand, this capability can be used potentially in bio-remediation technologies, and on the other hand, it requires additional, more thorough studies to identify its underlying mechanisms. Practically, no data are currently available on mechanisms for implementation of these radioadaptive properties by microscopic fungi. The objective of the completed study was to evaluate the functioning of the antioxidant system of a microscopic fungus as one of potential mechanisms for implementation of its radioadaptive properties. The study was performed using a model system simulating the soil radioactivity in the 5-km zone around the Chernobyl Nuclear Power Plant, with the ratio of the radioactive isotopes matching the radionuclide content in the fuel component of the Chernobyl fallout. The completed study was the first ever performed to identify a comprehensive response of the major components of the antioxidant system of the microscopic fungi to ionizing radiation, resulting in an induced melanin synthesis and increased activity of the known enzymes of antioxidant protection. Their response to ionizing radiation depended on the presence or absence of radioadaptive properties and phase of the fungal growth. Fungi with radioadaptive properties have a much higher susceptibility for inducing synthesis of melanin and antioxidant enzymes than fungi without radioadaptive properties (hereinafter referred to as the reference species or strains), which illustrates the contribution of these processes to "radiophilia" of the fungi.

  10. Composition, size distribution, optical properties, and radiative effects of laboratory-resuspended PM10 from geological dust of the Rome area, by electron microscopy and radiative transfer modelling

    Science.gov (United States)

    Pietrodangelo, A.; Salzano, R.; Bassani, C.; Pareti, S.; Perrino, C.

    2015-11-01

    In this work, new information has been gained on the laboratory-resuspended PM10 fraction from geological topsoil and outcropped rocks representative of the Rome area (Latium). Mineralogical composition, size distribution, optical properties and the surface radiative forcing efficiency (RFE) of dust types representing the compositional end members of this geological area have been addressed. A multi-disciplinary approach was used, based on chamber resuspension of raw materials and sampling of the PM10 fraction, to simulate field sampling at dust source, scanning electron microscopy/X-ray energy-dispersive microanalysis (SEM XEDS) of individual mineral particles, X-ray diffraction (XRD) analysis of bulk dust samples, building of number and volume size distribution (SD) from microanalysis data of mineral particles and fitting to a log-normal curve, and radiative transfer modelling (RTM) to retrieve optical properties and radiative effects of the compositional end-member dust samples. The mineralogical composition of Rome lithogenic PM10 varies between an end-member dominated by silicate minerals (from volcanics lithotypes), and one mostly composed of calcite (from travertine or limestones). Lithogenic PM10 with intermediate composition derives mainly from siliciclastic rocks or marlstones. Size and mineral species of PM10 particles of silicate-dominated dust types are tuned mainly by rock weathering and, to lesser extent, by debris formation or crystallization; chemical precipitation of CaCO3 plays a major role in calcite-dominated types. These differences are reflected in the diversity of volume distributions, either within dust types or mineral species. Differences are also observed between volume distributions of calcite from travertine (natural source; SD unimodal at 5 μm a.d.) and from road dust (anthropic source; SD bimodal at 3.8 and 1.8 μm a.d.). The volcanics and travertine dusts differently affect the single scattering albedo (SSA) and the asymmetry

  11. Influence of gamma radiation on thermal properties and water vapor transmission of poly(3-hydroxybutyrate) (PHB) in blends

    Energy Technology Data Exchange (ETDEWEB)

    Forster, Pedro L.; Martins, Natalia A.; Parra, Duclerc F.; Egute, Nayara S.; Lugao, Ademar B., E-mail: dfparra@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2009-07-01

    Biodegradable polymers are a newly emerging field. A vast number of biodegradable polymers have been synthesized recently and some microorganisms and enzymes capable of degrading them have been identified. Polyesters such as poly(3-hydroxybutyrate) (PHB) or other polyhydroxyalkanoates (PHAs) have attracted commercial and academic interest as new biodegradable materials. In this work, we investigated the effect of gamma radiation on the thermal properties and biodegradation behavior of PHB in blend with poly(ethyleneglycol)(PEG). The samples were irradiated at gamma radiation of 5 and 10 kGy. The thermal behaviour was investigated by utilization of differential scanning calorimetry (DSC) changes in thermal stability, glass transition and melting point were reported. (author)

  12. Preparation, Microstructure and Properties of NiO-Cr_2O_3-TiO_2 Infrared Radiation Coating

    Institute of Scientific and Technical Information of China (English)

    Wu Chen; Weiping Ye; Xudong Cheng; Wei Duan; Fang Mao; Deliang Li

    2009-01-01

    The spherical agglomerated particles were fabricated by spray drying with the powders of NiO, Cr_2O_3 and TiO2. Plasma spray power, which has good property of flowability, was acquired by heat treatment from the particles at 1200℃ in the reducing atmosphere. Dark and uniform coating of More than 50 μm thick was deposited on the copper sheet substrate by plasma spraying. It is found that the infrared normal total emissivity of the coating is up to 0.91 at 600℃ by infrared radiation testing. The X-ray diffraction analysis shows that the formation of (Cr_0.88Ti_0.12)_2O_3 and spinel structural NiCr_2O_4 in the coating is the main reason for high efficient infrared radiation, and the phase structure and performance of coating is favorable under the thermal cycle between room temperature and 600℃.

  13. The radiation swelling effect on fracture properties and fracture mechanisms of irradiated austenitic steels. Part II. Fatigue crack growth rate

    Science.gov (United States)

    Margolin, B.; Minkin, A.; Smirnov, V.; Sorokin, A.; Shvetsova, V.; Potapova, V.

    2016-11-01

    The experimental data on the fatigue crack growth rate (FCGR) have been obtained for austenitic steel of 18Cr-10Ni-Ti grade (Russian analog of AISI 321 steel) irradiated up to neutron dose of 150 dpa with various radiation swelling. The performed study of the fracture mechanisms for cracked specimens under cyclic loading has explained why radiation swelling affects weakly FCGR unlike its effect on fracture toughness. Mechanical modeling of fatigue crack growth has been carried out and the dependencies for prediction of FCGR in irradiated austenitic steel with and with no swelling are proposed and verified with the obtained experimental results. As input data for these dependencies, FCGR for unirradiated steel and the tensile mechanical properties for unirradiated and irradiated steels are used.

  14. Radiative property investigation. [digital computer programs for determining bidirectional reflectance of spacecraft materials

    Science.gov (United States)

    Scott, R. L., Jr.

    1974-01-01

    A detailed formulation of radiative heat transfer problems involving the use of bidirectional reflectance is discussed. Except for very simple systems this formulation is very intricate. For this reason and the fact that bidirectional data are scarce, such a formulation is not in common use. However, with the development of the digital computer there have been numerical methods developed for detailed radiative investigations using the bidirectional reflectance. Since computations using bidirectional reflectance are coming into use for spacecraft radiative studies, it is necessary to have reflectance data on the materials involved. Materials that are frequently studied are coatings which are used in controlling the thermal environment of spacecrafts. This study is primarily concerned with the bidirectional reflectance of zinc oxide which is one constituent commonly used for coatings.

  15. Evaluation of GISS SCM Simulated Cloud and Radiative Properties Using Both Surface and Satellite Observations

    Science.gov (United States)

    Kennedy, A. D.; Dong, X.; Xi, B.; Del Genio, A.; Wolf, A.; Minnis, P.; Khaiyer, M.; Doelling, D.; Nordeen, M.; Keyes, D.

    2009-05-01

    To evaluate the GISS SCM simulated cloud fractions, three years of surface and GOES satellite data have been collected at DOE ARM Southern Great Plains (SGP) site during 1999-2001. The GOES derived total and high cloud fractions from both 0.5° and 2.5° grid boxes are in excellent agreement with surface observations, suggesting that the ARM point observations can represent large areal observations. Compared to the ARM radar-lidar observed cloud fractions, the SCM simulated most mid-level clouds, overestimated low clouds, and underestimated total and high clouds with additional missed during the summer season. Further studies have revealed that the model simulated cloud fractions are strongly dependent on the large-scale synoptic pattern and its associated variables such as vertical motion and relative humidity. Because a significant amount of clouds over ARM SGP occur during synoptically quiescent conditions, the model has issues producing enough high cloud cover. This work suggests that alterations need to be made to the stratiform cloud scheme to better represent the sub-grid scale cloud variability in this case. The model simulated radiation budget is also evaluated with two years of collocated ARM surface radiation and CERES and GOES TOA radiation over the SGP site during March 2000-Dec. 2001. For this comparison, the model simulated surface and TOA radiation budgets agree well with surface and satellite observations (˜10 W m-2). Model simulated cloud optical depth, however, is about an order of magnitude higher than CERES/GOES retrievals, which may explain why the radiation budget is reasonable and yet total cloud fraction has a negative bias compared to observations. Further study is warranted to better understand how this impacts cloud radiative forcing.

  16. Measurement and Modeling of Vertically Resolved Aerosol Optical Properties and Radiative Fluxes Over the ARM SGP Site

    Science.gov (United States)

    Schmid, B.; Arnott, P.; Bucholtz, A.; Colarco, P.; Covert, D.; Eilers, J.; Elleman, R.; Ferrare, R.; Flagan, R.; Jonsson, H.

    2003-01-01

    In order to meet one of its goals - to relate observations of radiative fluxes and radiances to the atmospheric composition - the Department of Energy's Atmospheric Radiation Measurement (ARM) program has pursued measurements and modeling activities that attempt to determine how aerosols impact atmospheric radiative transfer, both directly and indirectly. However, significant discrepancies between aerosol properties measured in situ or remotely remain. One of the objectives of the Aerosol Intensive Operational Period (TOP) conducted by ARM in May 2003 at the ARM Southern Great Plains (SGP) site in north central Oklahoma was to examine and hopefully reduce these differences. The IOP involved airborne measurements from two airplanes over the heavily instrumented SGP site. We give an overview of airborne results obtained aboard the Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) Twin Otter aircraft. The Twin Otter performed 16 research flights over the SGP site. The aircraft carried instrumentation to perform in-situ measurements of aerosol absorption, scattering, extinction and particle size. This included such novel techniques as the photoacoustic and cavity ring-down methods for in-situ absorption (675 nm) and extinction (675 and 1550 nm) and a new multiwavelength, filter-based absorption photometer (467, 530, 660 nm). A newly developed instrument measured cloud condensation nucleus concentration (CCN) concentrations at two supersaturation levels. Aerosol optical depth and extinction (354-2139 nm) were measured with the NASA Ames Airborne Tracking 14-channel sunphotometer. Furthermore, up-and downwelling solar (broadband and spectral) and infrared radiation were measured using seven individual radiometers. Three up-looking radiometers werer mounted on a newly developed stabilized platform, keeping the instruments level up to aircraft pitch and roll angles of approximately 10(exp 0). This resulted in unprecedented continuous vertical profiles

  17. Effect of high-energy radiation and alkali treatment on the properties of cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Foeldvary, Cs.M. E-mail: foldvary@iki.kfki.hu; Takacs, E.; Wojnarovits, L

    2003-06-01

    The effect of the treatment with NaOH or tetramethyl ammonium hydroxide solutions on preirradiated cotton-cellulose was investigated. Both the radiation and the treatment with alkali solutions caused loss of weight in cellulose; however, there was a synergism, a high weight loss was observed during alkali treatment of preirradiated samples. The radiation caused scissions of the cellulose chains and during the treatment with aqueous alkaline solutions some smaller fragments dissolved, resulting in a strong absorbance of the solutions with maximum at around 268 nm. It was attributed to the absorbance of aldehyde/keto groups.

  18. Regional aerosol optical properties and radiative impact of the extreme smoke event in the European Arctic in spring 2006

    Directory of Open Access Journals (Sweden)

    C. Lund Myhre

    2007-11-01

    Full Text Available In spring 2006 a special meteorological situation occurred in the European Arctic region giving record high levels of air pollution. The synoptic situation resulted in extensive transport of pollution predominantly from agricultural fires in Eastern Europe into the Arctic region and record high air-pollution levels were measured at the Zeppelin observatory at Ny-Ålesund (78°54' N, 11°53' E in the period from 25 April to 12 May. In the present study we investigate the optical properties of the aerosols from this extreme event and we estimate the radiative forcing of this episode.

    We examine the aerosol optical properties from the source region and into the European Arctic and explore the evolution of the episode and the changes in the optical properties. A number of sites in Eastern Europe, Northern Scandinavia and Svalbard are included in the study. The observations show that the maximum AOD was from 2–3 May at all sites and varies from 0.52 to 0.87, and the corresponding Ångstrøm exponent was relatively large. Lidar measurements from Minsk, ALOMAR (Arctic Lidar Observatory for Middle Atmosphere Research at Andenes and Ny-Ålesund show that the aerosol layer was below 3 km at all sites the height is decreasing from the source region and into the Arctic. For the AERONET sites included (Minsk, Toravere, Hornsund we have further studied the evolution of the aerosol size. The single scattering albedo at Svalbard is provided for two sites; Ny-Ålesund and Hornsund. Importantly the calculated single scattering albedo based on the aerosol chemical composition and size distribution from Ny-Ålesund and the AERONET measurements at Hornsund are consistent. We have found strong agreement between the satellite daily MODIS AOD and the ground-based AOD observations. This agreement is crucial for accurate radiative forcing calculations. We calculate a strong negative radiative forcing for the most polluted days employing the analysed

  19. Aerosol optical properties and radiative effects over Manora Peak in the Himalayan foothills: seasonal variability and role of transported aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava, A.K. [Indian Institute of Tropical Meteorology (Branch), Prof Ramnath Vij Marg, New Delhi (India); Ram, K. [Institute of Environment and Sustainable Development, Banaras Hindu University, Varanasi (India); Singh, Sachchidanand, E-mail: ssingh@nplindia.org [Radio and Atmospheric Sciences Division, CSIR-National Physical Laboratory, New Delhi (India); Kumar, Sanjeev [Radio and Atmospheric Sciences Division, CSIR-National Physical Laboratory, New Delhi (India); Tiwari, S. [Indian Institute of Tropical Meteorology (Branch), Prof Ramnath Vij Marg, New Delhi (India)

    2015-01-01

    The higher altitude regions of Himalayas and Tibetan Plateau are influenced by the dust and black carbon (BC) aerosols from the emissions and long-range transport from the adjoining areas. In this study, we present impacts of advection of polluted air masses of natural and anthropogenic emissions, on aerosol optical and radiative properties at Manora Peak (∼ 2000 m amsl) in central Himalaya over a period of more than two years (February 2006–May 2008). We used the most updated and comprehensive data of chemical and optical properties available in one of the most climatically sensitive region, the Himalaya, to estimate atmospheric radiative forcing and heating rate. Aerosol optical depth (AOD) was found to vary from 0.04 to 0.45 with significantly higher values in summer mainly due to an increase in mineral dust and biomass burning aerosols due to transport. In contrast, single scattering albedo (SSA) varied from 0.74 to 0.88 with relatively lower values during summer, suggesting an increase in absorbing BC and mineral dust aerosols. As a result, a large positive atmospheric radiative forcing (about 28 ± 5 Wm{sup −2}) and high values of corresponding heating rate (0.80 ± 0.14 Kday{sup −1}) has been found during summer. During the entire observation period, radiative forcing at the top of the atmosphere varied from − 2 to + 14 Wm{sup −2} and from − 3 to − 50 Wm{sup −2} at the surface whereas atmospheric forcing was in the range of 3 to 65 Wm{sup −2} resulting in a heating rate of 0.1–1.8 Kday{sup −1}. - Highlights: • Aerosol chemical and optical properties at Manora Peak, in central Himalaya, were significantly affected by dust and black carbon (BC) aerosols from the emissions and long-range transport from the adjoining areas. • Elevated AOD and lower SSA values were observed at Manora Peak during summer. • Enhancement in absorbing aerosols was observed during summer. • Large aerosol radiative forcing and heating rate was observed

  20. OPTICAL RADIO-CHROMIC PROPERTIES OF POLYANILINE FILM IRRADIATED WITH GAMMA RADIATION

    Directory of Open Access Journals (Sweden)

    MOHAMMED AHMED ALI

    2010-06-01

    Full Text Available Aniline hydrochloride monomer has been polymerized to polyaniline salt (emeraldine salt and the characterization reveal that it is an electro-chromic material after direct -radiation exposure to high dose up to 50 kGy. The electro-chromic material which deduced by direct step wise appearance of light green color to dark green color following the radiation doses rather than colorless. The Radio-chromic and polymerization confirmed by using UV-visible spectroscopy, which gave rise to absorbance band at 790 nm, the absorbance band in turn increased following the dose exponentially. The band gap energy of PANI was obtained and showed to be decreases by increase of radiation dose down to 1 eV at 50 kGy. Raman spectroscopy showed a new bond C=N as a part of polaron conducting species is created by irradiation, which has Raman shift of 1637 cm-1. The double bond at C=N which is responsible for the appearance of the green color has been increases exponentially following the radiation dose.

  1. Radiation-optical properties of vitreous As{sub 2}S{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Shpotyuk, O.I.; Matkovskii, A.O. [Scientific Research Institute of Materials, Lvov (Ukraine)

    1994-12-31

    Physical features and microstructural mechanism of radiation-induced effects in vitreous As{sub 2}S{sub 3} are studied. Observed changes, i.e., long-wave shift of fundamental edge absorption, increase of longitudinal ultrasonic velocity, decrease of frequency normalized acoustic loss coefficient and acoustooptical figure of merit, etc. are described. (author). 19 refs, 6 figs, 1 tab.

  2. Light Absorption Properties and Radiative Effects of Primary Organic Aerosol Emissions

    Science.gov (United States)

    Organic aerosols (OA) in the atmosphere affect Earth’s energy budget by not only scattering but also absorbing solar radiation due to the presence of the so-called “brown carbon” (BrC) component. However, the absorptivities of OA are not or poorly represented in current climate m...

  3. Analysis on the Radiation Property of the Bounded Modes of Periodic Leaky-Wave Structure with Finite-Length Using a Hybrid Method.

    Science.gov (United States)

    Li, Zheng; Wang, Junhong; Duan, Jianjie; Zhang, Zhan; Chen, Meie

    2016-03-18

    In this paper the radiation property of the one-dimensional periodic leaky-wave structure is analysed using a new hybrid method, which involves the mode expansion method for expanding the periodic aperture field in terms of spatial harmonics and the method of effective radiation sections for transforming the expanded fields into far fields. Using this method, the radiation of each spatial harmonic can be achieved, and the contributions of the harmonics (especially the bounded modes) to the total radiation of the periodic leaky-wave structure can be calculated. The main findings in this paper demonstrate that the bounded modes in a finite length structure have obvious contribution to the far-field radiation, which was considered to be non-radiative and always ignored in the conventional researches.

  4. The modulating impact of illumination and background radiation on 8 Hz-induced infrasound effect on physicochemical properties of physiolagical solution.

    Science.gov (United States)

    Baghdasaryan, Naira; Mikayelyan, Yerazik; Barseghyan, Sedrak; Dadasyan, Erna; Ayrapetyan, Sinerik

    2012-12-01

    At present, when the level of background ionizing radiation is increasing in a number of world locations, the problem of the study of biological effect of high background radiation becomes one of the extremely important global problems in modern life sciences. The modern research in biophysics proved that water is a most essential target, through which the biological effects of ionizing and non-ionizing radiations are realized. Therefore, there is no doubt about the strong dependency of non-ionizing radiation-induced effect on the level of background radiation. Findings have shown that illumination and background radiation have a strong modulation effect on infrasound-induced impacts on water physicochemical properties, which could also have appropriate effect on living organisms.

  5. Variation of physical properties of LDPE greenhouse films due to agrochemicals used during cultivation

    Directory of Open Access Journals (Sweden)

    Evelia Schettini

    2013-09-01

    Full Text Available During protected cultivation, the use of agrochemicals influence the degradation of the greenhouse plastic films. A research was carried out to evaluate how agrochemicals contamination and solar radiation influence the physical properties of low density polyethylene (LDPE films. The LDPE films were manufactured on purpose adding different anti-UV stabilizer systems and were exposed to natural outdoor weathering at the experimental farm of the University of Bari (Italy; 41° 05’ N. Each film was tested as covering of two low tunnels: one was sprayed from inside with commercial agrochemicals containing iron, chlorine and sulphur while the other one was not sprayed and used as control. Radiometric tests were carried out on the new films and on film samples taken at the end of the trial. Analyses on absorption of the selected contaminants were carried out in laboratory on the samples taken at the end of the exposure in the field in order to compare the relative effectiveness of the stabilizing systems under evaluation. The experimental tests showed that the natural weathering together with the agrochemicals did not modify significantly the radiometric properties of the films in the solar and PAR wavelength range. Significant variations were recorded for the stabilised films in the LWIR wavelength range.

  6. Exploiting the power law distribution properties of satellite fire radiative power retrievals: A method to estimate fire radiative energy and biomass burned from sparse satellite observations

    Science.gov (United States)

    Kumar, S. S.; Roy, D. P.; Boschetti, L.; Kremens, R.

    2011-10-01

    Instantaneous estimates of the power released by fire (fire radiative power, FRP) are available with satellite active fire detection products. The temporal integral of FRP provides an estimate of the fire radiative energy (FRE) that is related linearly to the amount of biomass burned needed by the atmospheric emissions modeling community. The FRE, however, is sensitive to satellite temporal and spatial FRP undersampling due to infrequent satellite overpasses, cloud and smoke obscuration, and failure to detect cool and/or small fires. Satellite FRPs derived over individual burned areas and fires have been observed to exhibit power law distributions. This property is exploited to develop a new way to derive FRE, as the product of the fire duration and the expected FRP value derived from the FRP power law probability distribution function. The method is demonstrated and validated by the use of FRP data measured with a dual-band radiometer over prescribed fires in the United States and by the use of FRP data retrieved from moderate resolution imaging spectroradiometer (MODIS) active-fire detections over Brazilian deforestation and Australian savanna fires. The biomass burned derived using the conventional FRP temporal integration and power law FRE estimation methods is compared with biomass burned measurements (prescribed fires) and available fuel load information reported in the literature (Australian and Brazilian fires). The results indicate that the FRE power law derivation method may provide more reliable burned biomass estimates under sparse satellite FRP sampling conditions and correct for satellite active-fire detection omission errors if the FRP power law distribution parameters and the fire duration are known.

  7. LWIR Snapshot Imaging Polarimeter

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Robert E Sampson

    2009-04-01

    This report describes the results of a phase 1 STTR to design a longwave infrared imaging polarimeter. The system design, expected performance and components needed to construct the imaging polarimeter are described. Expected performance is modeled and sytem specifications are presented.

  8. Uncooled Tunable LWIR Microbolometer

    Science.gov (United States)

    2010-05-05

    Table.1 Layer structure of the experimental devices in this study. (The optical constants of these materials have been taken from Palik [17...ch. 3, pp. 43-121. [16] H. A. Macleod, Thin Film Optical filters. 3rd ed. Inst of Physics Pub Inc, (2001). [17] E. Palik , Handbook of optical...Collins, Phys. Rev, vol. 101, p. 566, 1956. [65] E. D. Palik , Handbook of Optical Constants of Solids. Elsevier, 1998. [66] D. R. Lide, Ed., CRC

  9. Comparison of the luminescent properties of LuAG:Pr nanopowders, crystals and films using synchrotron radiation

    Science.gov (United States)

    Gorbenko, V.; Zych, E.; Voznyak, T.; Nizankovskiy, S.; Zorenko, T.; Zorenko, Yu.

    2017-04-01

    Comparison of the luminescent properties of nanopowder, single crystal and single crystalline film of Pr3+ doped Pr-doped Lu3Al5O12 garnet (LuAG:Pr) prepared by the different technological methods is performed in this work using the time-resolved emission spectroscopy under excitation by synchrotron radiation with an energy of 3.7-25 eV at 300 K and 10 K. The notable differences in the properties of the Pr3+ luminescence are observed in LuAG:Pr crystals and films caused by involving the LuAl antisite defects and oxygen vacancies in crystals and Pb2+ flux related dopant in films in the excitation processes of the Pr3+ luminescence. At the same time, we have also found that the influence of host defects on the Pr3+ luminescence is significantly smaller in the LuAG:Pr nanopowders.

  10. Mechanical properties of cables exposed to simultaneous thermal and radiation aging

    Energy Technology Data Exchange (ETDEWEB)

    Jacobus, M.J. (Sandia National Labs., Albuquerque, NM (USA)); Fuehrer, G.F. (Science and Engineering Associates, Inc., Albuquerque, NM (USA))

    1990-01-01

    Sandia National Laboratories is conducting long-term aging research on representative samples of nuclear power plant Class 1E cables. The objectives of this program are to determine the suitability of these cables for extended life (beyond the 40-year design basis) and to assess various cable condition monitoring (CM) techniques for predicting remaining cable life. This paper provides the results of mechanical measurements that were performed on cable specimens cross-linked polyethylene neoprene jackets: chlorinated polyethylene jackets, fiberglass braid jackets, and chlorosulfonated polyethylene jackets aged at relatively mild, simultaneous thermal and radiation exposure conditions for periods of up to nine months. After aging, some of the aged samples, as well as some unaged samples, were exposed to accident gamma radiation at ambient temperature. The mechanical measurements discussed in this paper include tensile strength, ultimate elongation, and compressive modulus. 10 refs., 22 figs., 2 tabs.

  11. Effect of radiation on properties of ENR/PVC/SiO2 membrane

    Science.gov (United States)

    Ismail, Nur Farahein Hadina; Abdullah, Ibrahim; Daik, Rusli; Ahmad, Ishak; Jamil, Suzereen; Lazim, Mohammad Azwan Mat; Othaman, Rizafizah

    2015-09-01

    In this study epoxidised natural rubber (ENR)/polyvinyl chloride (PVC) matrix was prepared by melt blending. The matrix was swelled in THF and silica as a filler was introduced to the solution to generate pore formation. The ENR/PVC/10 % SiO2 membrane was prepared using a casting knife technique. The membrane was irradiated using 2 MeV electron beam accelerator at a dose range of 10-100 kGy. The effect of electron beam irradiation of the membrane was studied by undergo characterization of Scanning electron microscope (SEM) and Fourier transform infra red (FTIR). Morphological studies showed that pores generated in ENR/PVC/10 % SiO2 membrane increased with the dosage of radiation. While FTIR analysis showed the presence of peak of Si-O-Si asymmetric stretching at 834 cm-1. There are no significant changes in the functional group before and after radiation.

  12. Effect of antioxidants on thermooxidative stability and technological properties of radiation grafted foam polyethylene

    Energy Technology Data Exchange (ETDEWEB)

    Burukhina, G.A.; Berlyant, S.M.; Pleshanov, V.P.

    1986-04-01

    Foam polyethylene (FPE) is used in many industrial applications at temperatures of 65-70%. In order to increase this range of practical utilization the effect of oxidation inhibitors was studied along with thermal stabilization of FPE. It was shown that even with small amounts of antioxidants, the foaming coefficient decreased and the optimal radiation absorption dose increased. Therefore, during stabilization of FPE, the introduced antioxidants should not exceed a level of 1%. The use of soot (in excess of 3%) was found to be advantageous in many cases. It yielded material with greater resistance to photodestruction; ionizing radiation affected it to a minimal extent and it did not migrate from the plastic during exposure to high temperatures. Otherwise, amine antioxidants were more effective than the phenolic antioxidants. 6 references, 3 figures.

  13. Effect of radiation on properties of ENR/PVC/SiO{sub 2} membrane

    Energy Technology Data Exchange (ETDEWEB)

    Ismail, Nur Farahein Hadina; Abdullah, Ibrahim; Daik, Rusli; Ahmad, Ishak; Jamil, Suzereen; Lazim, Mohammad Azwan Mat; Othaman, Rizafizah [School of Chemical Sciences and Food Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor Darul Ehsan. Malaysia (Malaysia)

    2015-09-25

    In this study epoxidised natural rubber (ENR)/polyvinyl chloride (PVC) matrix was prepared by melt blending. The matrix was swelled in THF and silica as a filler was introduced to the solution to generate pore formation. The ENR/PVC/10 % SiO{sub 2} membrane was prepared using a casting knife technique. The membrane was irradiated using 2 MeV electron beam accelerator at a dose range of 10-100 kGy. The effect of electron beam irradiation of the membrane was studied by undergo characterization of Scanning electron microscope (SEM) and Fourier transform infra red (FTIR). Morphological studies showed that pores generated in ENR/PVC/10 % SiO{sub 2} membrane increased with the dosage of radiation. While FTIR analysis showed the presence of peak of Si-O-Si asymmetric stretching at 834 cm{sup −1}. There are no significant changes in the functional group before and after radiation.

  14. Effect of Microwave Heating on Infrared Radiation Properties of Cordierite-Ferrites Based Composite Ceramics

    Institute of Scientific and Technical Information of China (English)

    LU; Lei; FAN; Xi’an; HU; Xiaoming; ZHANG; Jianyi

    2015-01-01

    The cordierite-ferrites based infrared radiation composite materials were synthesized with Fe2O3, Mn O2, Cu O, Co2O3, and Mg2Al4Si5O18 powders as raw materials via microwave heating. The cordierite-ferrites based composite ceramics could be obtained via microwave heating at 1173 K for 1 h or 1473 K for 10 min, respectively. The lower synthesis temperature or the shorter heating time results in the smaller grain size of the composite ceramics obtained by microwave heating. The interplanar distance of cordierite becomes greater after microwave heating, indicating that the doping effect of transitional metal oxides on the cordierite is more efficient in microwave heating. The infrared radiation composite ceramics synthesized by microwave heating at 1473 K for 1 h exhibit the maximum emissivity of 0.9 in the band range of 6-8 μm at 1073 K.

  15. Characterization of COTS ADC radiation properties for ATLAS LAr calorimeter readout upgrade

    CERN Document Server

    Takai, H; The ATLAS collaboration; Chen, H; Chen, K; Lanni, F; Rescia, S

    2013-01-01

    The ATLAS LAr calorimeters plan to upgrade the readout electronics for both Phase-I and Phase-II LHC luminosity upgrades. Detector signals will be digitized at the front-end, and data will be streamed out to the back-end system continuously. Therefore, radiation tolerant ADCs are key components for both upgrade phases. This presentation will report on irradiation test results of commercial-off-the-shelf (COTS) ADCs that have potentials to be used in the readout electronics upgrade. Total-ionization-dose (TID) irradiation test results will be described, which has been used to pre-screen COTS ADCs for further studies. Various SEE studies of a candidate ADC with both neutron and proton beams will be presented. Finally, annealing studies following ATLAS policy on radiation tolerant electronics will be reported.

  16. Thermal analysis evaluation of mechanical properties changes promoted by gamma radiation on surgical polymeric textiles

    Science.gov (United States)

    Ferreira, L. M.; Casimiro, M. H.; Oliveira, C.; Cabeço Silva, M. E.; Marques Abreu, M. J.; Coelho, A.

    2002-05-01

    The large number of surgical operations with post-operative infection problems and the appearing of new infectious diseases, contribute to the development of new materials in order to answer the needs of health care services. This development must take into account the modifications promoted by sterilisation methods in materials, namely by gamma radiation. The differential scanning calorimetry (DSC) and thermogravimetry (TGA) techniques show that a nonwoven and a laminate textiles maintain a good molecular cohesion, do not showing high levels of degradation, for gamma radiation dose values lower than 100 kGy in nonwoven and 200 kGy in laminate materials. The tensile strength and the elongation decrease slowly for the nonwoven textile and decrease faster for the laminate textile for 25 and 80 kGy absorbed dose. This paper shows that the DSC and TGA techniques can be helpful for the prevision of mechanical changes occurred in the materials as a consequence of the gamma irradiation.

  17. Viscoelastic property tuning for reducing noise radiated by switched-reluctance machines

    Science.gov (United States)

    Millithaler, Pierre; Dupont, Jean-Baptiste; Ouisse, Morvan; Sadoulet-Reboul, Émeline; Bouhaddi, Noureddine

    2017-10-01

    Switched-reluctance motors (SRM) present major acoustic drawbacks that hinder their use for electric vehicles in spite of widely-acknowledged robustness and low manufacturing costs. Unlike other types of electric machines, a SRM stator is completely encapsulated/potted with a viscoelastic resin. By taking advantage of the high damping capacity that a viscoelastic material has in certain temperature and frequency ranges, this article proposes a tuning methodology for reducing the noise emitted by a SRM in operation. After introducing the aspects the tuning process will focus on, the article details a concrete application consisting in computing representative electromagnetic excitations and then the structural response of the stator including equivalent radiated power levels. An optimised viscoelastic material is determined, with which the peak radiated levels are reduced up to 10 dB in comparison to the initial state. This methodology is implementable for concrete industrial applications as it only relies on common commercial finite-element solvers.

  18. Effect of Flyash Addition on Mechanical and Gamma Radiation Shielding Properties of Concrete

    Directory of Open Access Journals (Sweden)

    Kanwaldeep Singh

    2014-01-01

    Full Text Available Six concrete mixtures were prepared with 0%, 20%, 30%, 40%, 50%, and 60% of flyash replacing the cement content and having constant water to cement ratio. The testing specimens were casted and their mechanical parameters were tested experimentally in accordance with the Indian standards. Results of mechanical parameters show their improvement with age of the specimens and results of radiation parameters show no significant effect of flyash substitution on mass attenuation coefficient.

  19. Molecular and kinetic properties of sperm specific LDH after radiation inactivation.

    Science.gov (United States)

    Gupta, G S; Kang, B P

    2000-03-01

    Radiation inactivation of sperm specific lactate dehydrogenase-C4 (LDH-C4) has been studied and compared with the somatic LDH in aqueous solution. D37 of C isozyme was 470 Gy and that of B isozyme was 520 Gy. Semi-log plots of log N/No versus dose suggested that the inactivation of two LDH isozymes in presence of normal saline follows a single hit kinetics. Target molecular weight calculated by radiation analysis was found as 1.52 x 10(5) gm/mole for LDH-C4 and 1.38 x 10(5) gm/mole for LDH-B4. SDS-PAGE of irradiated enzymes showed a band of 35 kDa but did not indicate the presence of any other extra band, when compared with sham-irradiated enzymes. Chemical kinetics of residual activity following irradiation at D37 showed decrease in Vmax with coenzymes and primary substrates. However, decrease in Km was seen with pyruvate as increasing substrate. Nevertheless, K did not change when NAD+ was the leading substrate for LDH-B4 or LDH-C4. A hyperchromicity in intrinsic fluorescence and a blue shift in lambdamax over sham-irradiated LDH-C4 revealed the exposure of buried tryptophan residues to the surface after radiation inactivation. Results suggest that inspite of presence of variant amino acids, the conformations of two isozymes are stabilized by similar forces which behave in a similar way for radiation inactivation in aqueous phase.

  20. Solar ultraviolet radiation: properties, characteristics and amounts observed in Brazil and South America

    OpenAIRE

    Corrêa,Marcelo de Paula

    2015-01-01

    Abstract The beneficial and harmful effects of human exposure to solar ultraviolet radiation (UV-R) are topics that arouse great interest not only among physicians and scientists, but also the general public and the media. Currently, discussions on vitamin D synthesis (beneficial effect) are confronted with the high and growing number of new cases of non-melanoma skin cancer and other diseases of the skin and eyes (harmful effect) diagnosed each year in Brazil. However, the lack of scientific...

  1. Synthesis and characterization of metal-polymer nanocomposites with radiation-protective properties

    Science.gov (United States)

    Bychkov, A. N.; Dzhardimalieva, G. I.; Fetisov, G. P.; Valskiy, V. V.; Golubeva, N. D.; Pomogailo, A. D.

    2016-12-01

    Metal-polymer nanocomposites, which can weaken the activity of a beta radiation source in undesirable directions at the minimum protection size, are developed. These nanocomposites are fabricated by dispersing metal-containing nanoparticles in thermoplastic matrices. Metal nanoparticles are synthesized by the polymerassisted thermolysis of metal-containing precursors. The composition and structure of the nanocomposites are characterized by elemental and X-ray diffraction analyses and transmission electron microscopy.

  2. Physical and Radiative Properties of Aerosol Particles in the Caribbean: Influence of African Dust and Soufriere Volcanic Ash

    Science.gov (United States)

    Villanueva-Birriel, C. M.; Mayol-Bracero, O. L.; Sheridan, P.; Ogren, J. A.

    2007-12-01

    Atmospheric particles such as dust and volcanic ash have the potential of influencing the earth's radiative budget directly by scattering or absorbing solar radiation in the atmosphere and indirectly by affecting cloud condensation nuclei (CCN) concentrations and, therefore, cloud albedo. The radiatively-important properties of atmospheric particles are determined at the most fundamental level by their chemical composition and size distributions; therefore, the importance of studying the chemical, physical, and optical aerosol properties. Over the summer months, the island of Puerto Rico receives African dust incursions that reduce visibility and have an impact on public health, ecosystem, and climate. Visibility is also negatively affected when the island receives south-east winds and the Soufriere volcano (Montserrat Island) has been active. Here we present preliminary results of measurements performed during 2006 and 2007 at Cape San Juan, a ground-based station located at the northeastern tip of Puerto Rico. The cases investigated showed three possible types of air masses: clean (C), with African Dust (AD), and with volcanic ash (VA) from the Soufriere. We used a condensation particle counter to determine the particle number concentration, a sunphotometer (part of the AERONET) to determine volume size distributions and aerosol optical thickness (AOT), a 3-wavelength nephelometer to determine the scattering coefficients, and a 3-wavelength particle/soot absorption photometer (PSAP) for the absorption coefficients. The particle number concentrations were higher for AD and VA periods (up to about 700 cm-3 on average for both cases) in contrast to ~400 cm-3 for the C period. Volume size distributions showed bimodal distributions for the three cases with a greater influence of the coarse fraction for the C and VA periods and an increase in the fine particles for the AD period. The total scattering coefficient showed higher values for the AD (30 Mm-1) and the VA (26

  3. Expected properties of the radiation from VUV-FEL at DESY femtosecond mode of operation

    CERN Document Server

    Saldin, E L; Yurkov, M V

    2004-01-01

    For the next three years the nominal "long pulse" (200 fs) mode of FEL operation at VUV-FEL, based on a linearized bunch compression, is not available due to the lack of a key element - a 3rd harmonic RF cavity. Essentially nonlinear compression leads naturally to a formation of a short high-current leading peak (spike) in the density distribution that produces FEL radiation. Such a mode of operation was successfully tested at VUV-FEL, Phase I. In this paper we present optimized parameters of the beam formation system that allow us to get a current spike which is bright enough to get SASE saturation for the VUV-FEL, Phase 2 at shortest design wavelength down to 6 nm. The main feature of the considered mode of operation is the production of short (15-50 fs FWHM) radiation pulses with GW-level peak power that are attractive for many users. Main parameters of the SASE FEL radiation (temporal and spectral characteristics, intensity distributions, etc.) are presented, too.

  4. General properties of the radiation spectra from relativistic electrons moving in a Langmuir turbulence

    CERN Document Server

    Teraki, Yuto

    2014-01-01

    We examine the radiation spectra from relativistic electrons moving in a Langmuir turbulence expected to exist in high energy astrophysical objects by using numerical method. The spectral shape is characterized by the spatial scale {\\lambda}, field strength {\\sigma}, and frequency of the Langmuir waves, and in term of frequency they are represented by {\\omega}_0 = 2{\\pi}c/{\\lambda}, {\\omega}_st = e{\\sigma}/mc, and {\\omega}_p, respectively. We normalize {\\omega}_st and {\\omega}_p by {\\omega}_0 as \\a \\equiv {\\omega}_st/{\\omega}_0 and \\b \\equiv{\\omega}_p/{\\omega}_0, and examine the spectral shape in the a-b plane. An earlier study based on Diffusive Radiation in Langmuir turbulence (DRL) theory by Fleishman and Toptygin showed that the typical frequency is {\\gamma}^2{\\omega}_p and that the low frequency spectrum behaves as F_{\\omega} pronto {\\omega}^1 for b > 1 irrespective of a. Here, we adopt the first principle numerical approach to obtain the radiation spectra in more detail. We generate Langmuir turbulence ...

  5. Gamma radiation effects on mechanical properties and morphology of a polyurethane derivate from castor oil

    Science.gov (United States)

    Azevedo, Elaine Cristina; Orivaldo Chierice, Gilberto; Claro Neto, Salvador; Scheidegger Soboll, Daniel; Mauro Nascimento, Eduardo; Lepienski, Carlos Mauricio

    2011-03-01

    In this study, an adhesive of a polyurethane derivate from castor oil was irradiated with gamma radiation from a 60Co source, at doses from 0.2 to 25 kGy. This adhesive polyurethane is considered for use in hospital furniture because it does not liberate dangerous solvents. Hardness and elastic modulus were measured by instrumented indentation with a pyramidal Berkovich indenter, using loads from 0.08-40 mN with a nanoindenter XP. The instrumented indentation hardness was 110 MPa for an untreated sample, increasing to 124 MPa after irradiation with 25 kGy, at penetration depths of about 5 μm. The increases in elastic modulus induced by radiation were less pronounced. This polyurethane is naturally cross-linked and the relative modifications in the hardness are attributed to an additional cross-linking process induced by radiation. X-ray diffraction indicates a slight increase in crystallinity. The roughness measured by atomic force microscopy increases after gamma irradiation.

  6. Properties of plasma radiation during discharges with improved confinement on HL-2A Tokamak

    Institute of Scientific and Technical Information of China (English)

    Gao Jin-Ming; Liu Yi; Li Wei; Cui Zheng-Ying; Zhou Yan; Huang Yuan; Ji Xiao-Quan

    2010-01-01

    In the recent experiment on the HL-2A tokamak,two types of improved confinement regimes have been achieved in different configurations.One is the improved confinement regime in Umiter configuration during electron cyclotron resonant heating(ECRH),characterized by a sharp decrease in Hσ emission accompanied by an increase in the total radiation of plasma,the line averaged electron density and the stored energy of plasma.The other is high confinement regime(H-mode)in divertor configuration during a combination of ECRH and Neutral beam injection(NBI)heating,characterized with edge localized modes(ELMs)besides the features mentioned above.The ELMs are found to be localized on the plasma edge(r/α≥0.8),causing average losses of particles and stored energy in the ranges of about1-3% and 3-5% respectively during a single ELM event.So far,the ELMs observed in the HL-2A are type Ⅲ ELMs with low amplitude and high repetition frequency in a range from 200 Hz to 350 Hz.An investigation of the radiated power density profiles shows that radiative cooling effect plays a significant role in the transition back to the L-mode and the triggering of ELM events.

  7. Influence of Radiation on the Dielectric Properties of XLPE Based Insulation Systems

    Science.gov (United States)

    Ďurman, Vladimír; Lelák, Jaroslav

    2010-07-01

    The paper discusses the possibilities of acquiring and processing the dielectric data in the range of very low frequency (VLF) and also design and construction of an impedance analyzer for measurements in this frequency range. The impedance measurements in the VLF range were used for investigation of the influence of radiation on the cross-linked polyethylene cable dielectric. An expressive β-type relaxation process was found in this type of cable. Most of the dielectric response parameters of the process depend significantly on the absorbed dose of radiation. The analysis of the process parameters showed that the most probable reason of the structural changes in cross-linked polyethylene was additional cross-linking. The results also proved that the impedance measurements in the VLF range could be effectively used in practice for estimation of the absorbed dose in the cross-linked polyethylene cables stressed by radiation.t data only. In order to identify or classify motion, data processing in real time is needed.

  8. Retrieval of Boundary Layer 3D Cloud Properties Using Scanning Cloud Radar and 3D Radiative Transfer

    Energy Technology Data Exchange (ETDEWEB)

    Marchand, Roger [Univ. of Washington, Seattle, WA (United States)

    2017-01-24

    Retrievals of cloud optical and microphysical properties for boundary layer clouds, including those widely used by ASR investigators, frequently assume that clouds are sufficiently horizontally homogeneous that scattering and absorption (at all wavelengths) can be treated using one dimensional (1D) radiative transfer, and that differences in the field-of-view of different sensors are unimportant. Unfortunately, most boundary layer clouds are far from horizontally homogeneous, and numerous theoretical and observational studies show that the assumption of horizontal homogeneity leads to significant errors. The introduction of scanning cloud and precipitation radars at the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) program sites presents opportunities to move beyond the horizontally homogeneous assumption. The primary objective of this project was to develop a 3D retrieval for warm-phase (liquid only) boundary layer cloud microphysical properties, and to assess errors in current 1D (non-scanning) approaches. Specific research activities also involved examination of the diurnal cycle of hydrometeors as viewed by ARM cloud radar, and continued assessment of precipitation impacts on retrievals of cloud liquid water path using passive microwaves.

  9. Acoustic radiation force impulse (ARFI) imaging: Characterizing the mechanical properties of tissues using their transient response to localized force

    Science.gov (United States)

    Nightingale, Kathryn R.; Palmeri, Mark L.; Congdon, Amy N.; Frinkely, Kristin D.; Trahey, Gregg E.

    2004-05-01

    Acoustic radiation force impulse (ARFI) imaging utilizes brief, high energy, focused acoustic pulses to generate radiation force in tissue, and conventional diagnostic ultrasound methods to detect the resulting tissue displacements in order to image the relative mechanical properties of tissue. The magnitude and spatial extent of the applied force is dependent upon the transmit beam parameters and the tissue attenuation. Forcing volumes are on the order of 5 mm3, pulse durations are less than 1 ms, and tissue displacements are typically several microns. Images of tissue displacement reflect local tissue stiffness, with softer tissues (e.g., fat) displacing farther than stiffer tissues (e.g., muscle). Parametric images of maximum displacement, time to peak displacement, and recovery time provide information about tissue material properties and structure. In both in vivo and ex vivo data, structures shown in matched B-mode images are in good agreement with those shown in ARFI images, with comparable resolution. Potential clinical applications under investigation include soft tissue lesion characterization, assessment of focal atherosclerosis, and imaging of thermal lesion formation during tissue ablation procedures. Results from ongoing studies will be presented. [Work supported by NIH Grant R01 EB002132-03, and the Whitaker Foundation. System support from Siemens Medical Solutions USA, Inc.

  10. A 640×512-20μm dual-polarity ROIC for MWIR and LWIR hybrid FPAs

    Science.gov (United States)

    Eminoglu, Selim; Incedere, O. Samet; Bayhan, Nusret; Isikhan, Murat; Soyer, S. T.; Ustundag, C. M. B.; Kocak, Serhat; Turan, Ozge; Eksi, Umut; Akin, Tayfun

    2016-05-01

    This paper reports the development of a new dual-polarity Direct-Injection (DI) Readout Integrated Circuit (ROIC), called MT6420DDA, designed to support back-to-back connected photodiodes with a single contact per pixel using dual pixel input circuitries suitable for both p-on-n and n-on-p type detectors. The ROIC has a format of 640 × 512 (VGA) and a pixel pitch of 20μm, and can be used to build dual-color or dual-band FPAs working in the MWIR and/or LWIR bands. The ROIC supports snapshot operation with Integrate-then-Read (ITR) and Integrate-while-Read modes (IWR). MT6420DDA has a system-on-chip architecture, with programmable biasing, timing, and configuration. The ROIC supports 2, 4, and 8-output modes at pixel output rates up to 12.5 MHz per output. It runs on 3.3 V analog and 1.8 V digital supplies, and dissipates less than 135 mW in the 4-output mode at 10 MHz. The ROIC has separate programmable full well capacitance values of 1.5 Me-, 3.0 Me-, and 6.0 Me- for both polarities in the high-gain (HG), mid-gain (MG), and low-gain (LG) modes. The ROIC supports two type of polarity switching modes as PSBF (Polarity Switching between Frames) and PSWF (Polarity Switching within Frames). In the PSBF modes, an alternating input polarity is used for each detector type for each frame during each integration period, possibly with different full-well and integration time settings. In the PSWF mode, both type of pixels are exposed almost simultaneously, where detector current is integrated in a time multiplexed manner using the two separate integration capacitors of the pixel input circuitry. The PSBF mode is simple, but the time stamp for each image frame is different. The PSWF mode is complex, but results in a pseudo simultaneous registration of images for each color or spectral band. The ROIC has been developed for cryogenic operation down to 65K with an input referred noise level of less than 470 e- rms in the low-gain (LG) mode at 77K. The MT6420DDA ROIC has been

  11. The effect of an additional phosphite stabilizer on the properties of radiation cross-linked vitamin E blends of UHMWPE.

    Science.gov (United States)

    Oral, Ebru; Neils, Andrew; Yabannavar, Pooja; Muratoglu, Orhun K

    2014-06-01

    Antioxidant stabilization of radiation cross-linked ultrahigh molecular weight polyethylene (UHMWPE) has been introduced to improve the oxidative stability of total joint implant bearing surfaces. Blending of an antioxidant with UHMWPE resin powder followed by consolidation and radiation cross-linking has been cleared by the FDA for use in both total hips and total knees for designs incorporating two antioxidants, namely vitamin E and Covernox™ (a medical grade version of Irganox™ 1010). The antioxidants in the polymer are expected to protect the polymer during consolidation, during radiation cross-linking, on the shelf before implantation, and in vivo after implantation. To maximize the protection of the polymer afforded by the antioxidant in vivo, a novel approach may be the use of multiple antioxidants, especially to protect the primary antioxidant for a longer period of time. We hypothesized that the addition of a phosphite stabilizer (Irgafos 168™) commonly used in conjunction with hindered phenolic antioxidants in polymer processing could improve the oxidative stability of radiation cross-linked blends of vitamin E. To test our hypothesis, we prepared UHMWPE blends with 0.05 wt% Irgafos and 0.05 wt% vitamin E and compared its cross-link density, wear resistance, tensile properties, and impact strength to control blends containing only vitamin E. Our hypothesis was not supported; the cross-link density of UHMWPE was significantly decreased by the additive without additional benefit to oxidative stability. To our knowledge, this was the first attempt at using multiple stabilizers in medical grade UHMWPE.

  12. Effect of electron beam radiation processing on mechanical and thermal properties of fully biodegradable crops straw/poly (vinyl alcohol) biocomposites

    Science.gov (United States)

    Guo, Dan

    2017-01-01

    Fully biodegradable biocomposites based on crops straw and poly(vinyl alcohol) was prepared through thermal processing, and the effect of electron beam radiation processing with N,N-methylene double acrylamide as radiation sensitizer on mechanical and thermal properties of the biocomposites were investigated. The results showed that, when the radiation dose were in the range of 0-50 kGy, the mechanical and thermal properties of the biocomposites could be improved significantly through the electron beam radiation processing, and the interface compatibility was also improved because of the formation of stable cross-linked network structure, when the radiation dose were above the optimal value (50 kGy), the comprehensive properties of the biocomposites were gradually destroyed. EB radiation processing could be used as an effective technology to improve the comprehensive performance of the biocomposites, and as a green and efficient processing technology, radiation processing takes place at room temperature, and no contamination and by-product are possible.

  13. Retrieval of Fog/Low Stratus Microphysical Properties at Night with MSG/SEVIRI - A Comparison of Two Radiative Transport Models: Streamer and libRadtran

    Science.gov (United States)

    Merk, C.; Cermak, J.; Bendix, J.

    2009-04-01

    Fog and low stratus (FLS) impact on traffic safety and air quality; knowledge of the FLS distribution in time and space therefore is of great value. A new algorithm is developed to detect fog and low stratus with MSG/SEVIRI data at night. An essential component of this study needed for the discrimination between elevated and ground fog is the derivation of microphysical properties of low clouds. A radiative transfer model is used to model optical and microphysical properties (optical thickness, effective droplet radius and liquid water path) to create a lookup table for the operational algorithm. To find a suitable radiative transfer model for this study, two models are compared: Streamer and libRadtran. Streamer is a radiative transfer model that can be used for a wide variety of atmospheric and surface conditions. The computing time is relatively short and it is easy to handle, but the MSG/SEVIRI channels are represented only coarsely by the radiative transfer code's bands. Absorption effects may lead to inaccuracies in infrared channels. Streamer has got two radiative transfer solvers. LibRadtran is a library of radiative transfer routines and programs. The central program can be used as a tool for the simulation of instrument signals. It has got eight radiative transfer solvers. There are four different methods given for the spectral calculations, depending on the time and the purpose of the calculation is used for. For both radiative transfer models, all infrared channels except the water vapour channels are used and the optical thickness, effective droplet radius, surface temperature and the satellite zenith angle are varied. The aim of this study is to find out which radiative transfer model is most useful for the retrieval of FLS microphysics. Output from both radiative transfer models is presented and compared. The implementation in FLS property retrieval is shown and discussed.

  14. Effect of radiation on the microstructure and mechanical property of ultrahigh molecular weight polyethylene used in orthopedic prostheses

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Phil Hyun; Nho, Young Chang [KAERI, Daejon (Korea, Republic of)

    2004-07-01

    The effect of radiation on the microstructure and mechanical property of ultra high molecular weight ployethylene (UHMWPE) used in orthopedic implants was investigated. The raw material used in this study was GUR 4150 ram extruded UHMWPE bar. The UHMWPE specimen was irradiated at 140{open_square} in oil and room temperature under nitrogen with different dosages of an electron beam (EB) for the purposes of enhancing the crosslinking extent of the polymer. Following irradiation at room temperature, the UHMWPE specimens were thermally treated at various temperature to eliminate all the remaining free radicals. Surface oxidation of the UHMWPE samples according to the irradiation and thermal treating conditions were verified by FTIR-ATR. An electron spin resonance (ESR) spectroscopic study was Undertaken to investigate the remaining radicals in UHMWPE. The crystalline structure and mechanical properties of the irradiated UHMWPE were compared after the crosslinking of the EB. The crystalline structure and degree of crystallinity of irradiated UHMWPE were investigated using DSC, SAXS and WAXD. Mechanical properties such as the tensile strength were measured. The polymer pin on a metal plate type testing apparatus was used to test the wear property. The melt-irradiated samples had a higher crosslinking extent compared with the room temperature-irradiated and the UHMWPE control. The crystallinity and lamellar thickness of UHMWPE irradiated at room temperature increased much more comparing with specimens irradiated at 140{open_square}. The melt-irradiated UHMWPE had a better wear resistance than the room temperature-irradiated and the UHMWPE control.

  15. Radiation hardness by design for mixed signal infrared readout circuit applications

    Science.gov (United States)

    Gaalema, Stephen; Gates, James; Dobyns, David; Pauls, Greg; Wall, Bruce

    2013-09-01

    Readout integrated circuits (ROICs) to support space-based infrared detection applications often have severe radiation tolerance requirements. Radiation hardness-by-design (RHBD) significantly enhances the radiation tolerance of commercially available CMOS and custom radiation hardened fabrication techniques are not required. The combination of application specific design techniques, enclosed gate architecture nFETs and intrinsic thin oxide radiation hardness of 180 nm process node commercial CMOS allows realization of high performance mixed signal circuits. Black Forest Engineering has used RHBD techniques to develop ROICs with integrated A/D conversion that operate over a wide range of temperatures (40K-300K) to support infrared detection. ROIC radiation tolerance capability for 256x256 LWIR area arrays and 1x128 thermopile linear arrays is presented. The use of 130 nm CMOS for future ROIC RHBD applications is discussed.

  16. The influence of the earth radiation on space target detection system

    Science.gov (United States)

    Su, Xiaofeng; Chen, FanSheng; Cuikun, .; Liuyan, .

    2017-05-01

    In the view of space remote sensing such as satellite detection space debris detection etc. visible band is usually used in order to have the all-weather detection capability, long wavelength infrared (LWIR) detection is also an important supplement. However, in the tow wave band, the earth can be a very strong interference source, especially in the dim target detecting. When the target is close to the earth, especially the LEO target, the background radiation of the earth will also enter into the baffle, and became the stray light through reflection, the stray light can reduce the signal to clutter ratio (SCR) of the target and make it difficult to be detected. In the visible band, the solar albedo by the earth is the main clutter source while in the LWIR band the radiation of the earth is the main clutter source. So, in this paper, we establish the energy transformation from the earth background radiation to the detection system to assess the effects of the stray light. Firstly, we discretize the surface of the earth to different unit, and using MODTRAN to calculate the radiation of the discrete point in different light and climate conditions, then, we integral all the radiation which can reach the baffle in the same observation angles to get the energy distribution, finally, according the target energy and the non-uniformity of the detector, we can calculate the design requirement of the system stray light suppression, which provides the design basis for the optical system.

  17. The antioxidant properties of oligo sodium alginates prepared by radiation-induced degradation in aqueous and hydrogen peroxide solutions

    Science.gov (United States)

    Şen, Murat; Atik, Hanife

    2012-07-01

    In this study, the radiation-induced degradation of sodium alginates (NaAlg), having different guluronic acids (G) and mannuronic acid (M) ratios, (G/M), in aqueous and hydrogen peroxide solutions were investigated first; after that, the antioxidative properties of the oligo sodium alginates prepared were identified. Radiation degradation yield values, G(S), were determined for each irradiation condition and compared with those of the dry-state-irradiated NaAlg. The results showed that the oligo sodium alginates with M from 1000 to 3750 Da could be easily prepared by γ-irradiation of NaAlg solution in the presence of small amount of hydrogen peroxide at low doses (below 5.0 kGy) and by controlling the G/M. The antioxidant properties of the fractions with various molecular weight and G/M were evaluated by determining the scavenging ability of 1,1-diphenyl-2-picrylhydrazyl free radical (DPPHrad ), and 50% inhibition concentrations of LF120 NaAlg, which was irradiated in aqueous solution and H2O2 solution at a dose of 2.5 kGy and having number average molecular weights of 10.2 and 3.75 kDa were found to be 10.0 and 2.5 mg/ml, respectively. The results demonstrated that its molecular weight was an important factor in controlling the antioxidant properties of NaAlg, and due to the sharp decrease in molecular weight in the case of aqueous media irradiation the effect of G/M of initial polymer became unimportant whereas the dry-state-irradiated NaAlgs behaved conversely.

  18. Collective properties of quantum matter: from Hawking radiation analogues to quantum Hall effect in graphene

    CERN Document Server

    de Nova, J R M

    2015-01-01

    The work is divided in three parts. We devote the first part to the study of analog Hawking radiation in Bose-Einstein condensates. We study numerically the birth of a sonic black hole in an outcoupled Bose-Einstein condensate after relaxing the confinement provided by an optical lattice. We also study possible signatures of spontaneous Hawking radiation. We propose that the violation of CS inequalities is a smoking gun of the presence of the Hawking effect. We compare this criterion with the presence of entaglement, finding that both are equivalent under usual assumptions. Finally, we study a different gravitational analogue: the so-called black-hole laser. The most interesting result is the appearance of a regime of continuous and periodic emission of solitons, providing the most strong analogue with optical lasers. In the second part, we analyze the effect of the introduction of a short Bragg pulse in a thermal cloud. We show that the induced periodic density pattern decays to the equilibrium profile. Howe...

  19. Transient effects of ionizing and displacive radiation on the dielectric properties of ceramics

    Science.gov (United States)

    Goulding, R. H.; Zinkle, S. J.; Rasmussen, D. A.; Stoller, R. E.

    1996-03-01

    A resonant cavity technique was used to measure the dielectric constant and loss tangent of ceramic insulators at a frequency near 100 MHz during pulsed fission reactor irradiation near room temperature. Tests were performed on single crystal and several different grades of polycrystalline Al2O3, MgAl2O4, AlN, and Si3N4. Lead shielding experiments were performed for some of the irradiations in order to examine the importance of gamma ray versus neutron irradiation effects. With the exception of AlN, the dielectric constant of all of the ceramics decreased slightly (radiation fields of 4.2×104 Gy/s and 2.4×10-6 dpa/s, respectively. The loss tangent measured during irradiation for the different ceramics did not show any correlation with the preirradiation or postirradiation values. Analysis of the results indicates that the transient increases in loss tangent are due to radiation induced increases in the electrical conductivity. The loss tangent increases were proportional to the ionizing dose rate in all materials except for AlN, which exhibited a dose rate exponent of ˜1.6.

  20. Radiation Transfer of Models of Massive Star Formation. I. Dependence on Basic Core Properties

    CERN Document Server

    Zhang, Yichen

    2011-01-01

    Radiative transfer calculations of massive star formation are presented. These are based on the Turbulent Core Model of McKee & Tan and self-consistently included a hydrostatic core, an inside-out expansion wave, a zone of free-falling rotating collapse, wide-angle dust-free outflow cavities, an active accretion disk, and a massive protostar. For the first time for such models, an optically thick inner gas disk extends inside the dust destruction front. This is important to conserve the accretion energy naturally and for its shielding effect on the outer region of the disk and envelope. The simulation of radiation transfer is performed with the Monte Carlo code of Whitney, yielding spectral energy distributions (SEDs) for the model series, from the simplest spherical model to the fiducial one, with the above components each added step-by-step. Images are also presented in different wavebands of various telescope cameras, including Spitzer IRAC and MIPS, SOFIA FORCAST and Herschel PACS and SPIRE. The exist...

  1. Radiative properties of high wire number tungsten arrays with implosion times up to 250 ns

    Science.gov (United States)

    Deeney, C.; Coverdale, C. A.; Douglas, M. R.; Struve, K. W.; Spielman, R. B.; Stygar, W. A.; Peterson, D. L.; Roderick, N. F.; Haines, M. G.; Beg, F. N.; Ruiz-Camacho, J.

    1999-09-01

    High wire number, 25-mm-diameter tungsten wire arrays have been imploded on the 8-MA Saturn generator [R. B. Spielman et al., AIP Conference Proceeding 195, 3 (American Institute of Physics, Woodbury, NY 1989)], operating in a long-pulse mode. By varying the mass of the arrays from 710 to 6140 μg/cm, implosion times of 130-250 ns have been obtained with implosion velocities of 50-25 cm/μs, respectively. These Z-pinch implosions produced plasmas with millimeter diameters that radiated 600-800 kJ of x-rays, with powers of 20-49 TW; the corresponding pulsewidths were 19-7.5 ns, with risetimes ranging from 6.5 to 4.0 ns. These powers and pulsewidths are similar to those achieved with 50-ns implosion times on Saturn. Two-dimensional, radiation-magnetohydrodynamic calculations indicate that the imploding shells in these long implosion time experiments are comparable in width to those in the short-pulse cases. This can be due to lower initial perturbations. A heuristic wire array model suggests that the reduced perturbations, in the long-pulse cases, may be due to the individual wire merger occurring well before the acceleration of the shell. The experiments and modeling suggest that 150-200 ns implosion time Z-pinches could be employed for high-power, x-ray source applications.

  2. Effect of spine-like surface structures on the radiative properties of microorganism

    Science.gov (United States)

    Dong, J.; Zhao, J. M.; Liu, L. H.

    2016-04-01

    Many species of microorganisms possess spine-like surface structures. In this paper, we built a sphere with surface spines (SSS) model to represent such featured particles. The volume fraction of surface spines varied from 0% to 22% and the effects of the relative length, number, and radius of the spines on the radiation characteristics were studied using the discrete dipole approximation method with a complex relative refractive index of m=1.05+0.005i. Meanwhile, the approximations by the equivalent volume sphere (EVS) and the core shell sphere (CSS) models were examined. Surface spines led to increased scattering and absorption cross sections and asymmetry parameter. The EVS model overestimated the scattering cross section and underestimated the asymmetry parameter of SSS, the relative errors of which can exceed 10%, but EVS predicted the absorption cross section well. The CSS model combined with the Maxwell-Garnett mixing rule predicted the integral radiation parameters with relative errors less than 5% in all the cases, which was also valid for relative refractive indices with an imaginary part up to 0.1 and a real part up to 1.2. The resonance peaks of the phase function and Mueller matrix elements in the back scattering directions were damped out due to the existence of surface spines for size parameters larger than 10, which could not be captured by either the EVS or the CSS models.

  3. Direct Measure of Radiative and Dynamical Properties of an Exoplanet Atmosphere

    CERN Document Server

    de Wit, Julien; Langton, Jonathan; Laughlin, Gregory; Deming, Drake; Batygin, Konstantin; Fortney, Jonathan J

    2016-01-01

    Two decades after the discovery of 51 Peg b, the formation processes and atmospheres of short-period gas giants remain poorly understood. Observations of eccentric systems provide key insights on those topics as they can illuminate how a planet's atmosphere responds to changes in incident flux. We report here the analysis of multi-day multi-channel photometry of the eccentric (e~ 0.93) hot Jupiter HD 80606 b obtained with the Spitzer Space Telescope. The planet's extreme eccentricity combined with the long coverage and exquisite precision of new periastron-passage observations allow us to break the degeneracy between the radiative and dynamical timescales of HD 80606 b's atmosphere and constrain its global thermal response. Our analysis reveals that the atmospheric layers probed heat rapidly (~4 hr radiative timescale) from $\\lt$500 to 1400 K as they absorb ~ 20% of the incoming stellar flux during the periastron passage, while the planet's rotation period is 93$\\pm_{35}^{85}$ hr, which exceeds the predicted ...

  4. Visible absorption properties of radiation exposed XR type-T radiochromic film.

    Science.gov (United States)

    Butson, Martin J; Cheung, Tsang; Yu, Peter K N

    2004-10-01

    The visible absorption spectra of Gafchromic XR type-T radiochromic film have been investigated to analyse the dosimetry characteristics of the film with visible light densitometers. Common densitometers can use photospectrometry, fluorescent light (broad-band visible), helium neon (632 nm), light emitting diode (LED) or other specific bandwidth spectra. The visible absorption spectra of this film when exposed to photon radiation show peaks at 676 nm and 618 nm at 2 Gy absorbed doses which shift to slightly lower wavelengths (662 nm and 612 nm at 8 Gy absorbed dose) at higher doses. This is similar to previous models of Gafchromic film such as MD-55-2 and HS but XR type-T also includes a large absorption at lower visible wavelengths due to 'yellow' dyes placed within the film to aid with visible recognition of the film exposure level. The yellow dye band pass is produced at approximately 520 nm to 550 nm and absorbs wavelengths lower than this value within the visible spectrum. This accounts for the colour change from yellow to brown through the added absorption in the red wavelengths with radiation exposure. The film produces a relatively high dose sensitivity with up to 0.25 OD units per Gy change at 672 nm at 100 kVp x-ray energy. Variations in dose sensitivity can be achieved by varying wavelength analysis.

  5. Structural properties of the metastable state of phase change materials investigated by synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Merkelbach, Philipp; Eijk, Julia van; Wuttig, Matthias [I. Phys. Institut (IA), RWTH Aachen, 52056 Aachen (Germany); Braun, Carolin [Institut fuer Anorg. Chemie, CAU Kiel, 24098 Kiel (Germany)

    2008-07-01

    Phase change alloys are among the most promising materials for novel data storage devices. Since several years Phase Change Materials based on Ge-Sb-Te- alloys have been used in optical data storage solutions like rewriteable CDs and DVDs. Recently these alloys have been explored as potential candidates for fast nonvolatile electrical data storage devices in Phase Change Random Access Memory (PCRAM). Besides attracting considerable interest from the commercial point of view phase change materials are very interesting also due to their remarkable physical properties. They have the ability to be reversibly switched within a few nanoseconds between the amorphous and the crystalline phase, while changing their physical properties such as optical reflectivity and electrical resistivity significantly. Even though the electronic properties show a drastical contrast such fast transitions can only be caused by small atomic rearrangements. This behavior calls for a deeper understanding of the structural properties of the alloys. We have performed powder diffraction measurements of the crystal phase of various GeSbTe alloys, to determine the structural similarities and differences of several alloys. Understanding the crystal structure of phase change materials is a key to a deeper insight into the properties of these promising materials.

  6. Theoretical and experimental studies of the radiative properties of matter at high energy densities and their application to the problems of inertial confinement fusion

    Energy Technology Data Exchange (ETDEWEB)

    Denisov, O. B.; Orlov, N. Yu. [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation)

    2011-09-15

    The paper presents the results of theoretical and experimental studies of the radiative properties of plasmas produced by heating and compression of various materials to high energy densities. The specific features of the theoretical plasma model known as the ion model, which is used to calculate the radiative characteristics of plasmas of complex chemical composition, are discussed. The theoretical approach based on this model is applied to the plasma produced during the explosion of the X-pinch wires. The theoretical estimate of the radiation efficiency is compared with the experimental data on the total energy yield from an X-pinch made of two different wires (NiCr and Alloy 188). The radiative characteristics of (C12 H16 O8) and (C8 H12 O6) plasmas are calculated for the temperature diagnostics of plasmas produced from porous targets employed in inertial confinement fusion experiments with the use of laser radiation and heavy-ion beams.

  7. Composition, size distribution, optical properties and radiative effects of re-suspended local mineral dust of Rome area by individual-particle microanalysis and radiative transfer modelling

    Directory of Open Access Journals (Sweden)

    A. Pietrodangelo

    2015-05-01

    Full Text Available New information on the PM10 mineral dust from site-specific (Rome area, Latium outcropped rocks, and on the microphysics, optical properties and radiative effects of mineral dust at local level were gained in this work. A multi-disciplinary approach was used, based on individual-particle scanning electron microscopy with X-ray energy-dispersive microanalysis (SEM XEDS, X-ray diffraction (XRD analysis of dust, size distribution of mineral particles, and radiative transfer modelling (RTM.The mineral composition of Rome lithogenic PM10 varies between an end-member dominated by silicate minerals and one exclusively composed of calcite. The first is obtained from volcanic lithotypes, the second from travertine or limestones; lithogenic PM10 with intermediate composition derives mainly from siliciclastic rocks or marlstones of Rome area. Size and mineral species of PM10 particles of silicate-dominated dust types are tuned mainly by weathering and, to lesser extent, by debris formation or crystallization; chemical precipitation of CaCO3 plays a major role in calcite-dominated types. These differences are evidenced by the diversity of volume distributions, within either dust types, or mineral species. Further differences are observed between volume distributions of calcite from travertine (natural source and from road dust (anthropic source, specifically on the width, shape and enrichment of the fine fraction (unimodal at 5 μm a.d. for travertine, bimodal at 3.8 and 1.8 μm a.d. for road dust. Log-normal probability density functions of volcanics and travertine dusts affect differently the single scattering albedo (SSA and the asymmetry parameter (g in the VISible and Near Infrared (NIR regions, depending also on the absorbing/non-absorbing character of volcanics and travertine, respectively. The downward component of the BOA solar irradiance simulated by RTM for a volcanics-rich or travertine-rich atmosphere shows that volcanics contribution to the

  8. Composition, size distribution, optical properties and radiative effects of re-suspended local mineral dust of Rome area by individual-particle microanalysis and radiative transfer modelling

    Science.gov (United States)

    Pietrodangelo, A.; Salzano, R.; Bassani, C.; Pareti, S.; Perrino, C.

    2015-05-01

    New information on the PM10 mineral dust from site-specific (Rome area, Latium) outcropped rocks, and on the microphysics, optical properties and radiative effects of mineral dust at local level were gained in this work. A multi-disciplinary approach was used, based on individual-particle scanning electron microscopy with X-ray energy-dispersive microanalysis (SEM XEDS), X-ray diffraction (XRD) analysis of dust, size distribution of mineral particles, and radiative transfer modelling (RTM).The mineral composition of Rome lithogenic PM10 varies between an end-member dominated by silicate minerals and one exclusively composed of calcite. The first is obtained from volcanic lithotypes, the second from travertine or limestones; lithogenic PM10 with intermediate composition derives mainly from siliciclastic rocks or marlstones of Rome area. Size and mineral species of PM10 particles of silicate-dominated dust types are tuned mainly by weathering and, to lesser extent, by debris formation or crystallization; chemical precipitation of CaCO3 plays a major role in calcite-dominated types. These differences are evidenced by the diversity of volume distributions, within either dust types, or mineral species. Further differences are observed between volume distributions of calcite from travertine (natural source) and from road dust (anthropic source), specifically on the width, shape and enrichment of the fine fraction (unimodal at 5 μm a.d. for travertine, bimodal at 3.8 and 1.8 μm a.d. for road dust). Log-normal probability density functions of volcanics and travertine dusts affect differently the single scattering albedo (SSA) and the asymmetry parameter (g) in the VISible and Near Infrared (NIR) regions, depending also on the absorbing/non-absorbing character of volcanics and travertine, respectively. The downward component of the BOA solar irradiance simulated by RTM for a volcanics-rich or travertine-rich atmosphere shows that volcanics contribution to the solar

  9. Near-infrared radiation absorption properties of covellite (CuS using first-principles calculations

    Directory of Open Access Journals (Sweden)

    Lihua Xiao

    2016-08-01

    Full Text Available First-principles density functional theory was used to investigate the electronic structure, optical properties and the origin of the near-infrared (NIR absorption of covellite (CuS. The calculated lattice constant and optical properties are found to be in reasonable agreement with experimental and theoretical findings. The electronic structure reveals that the valence and conduction bands of covellite are determined by the Cu 3d and S 3p states. By analyzing its optical properties, we can fully understand the potential of covellite (CuS as a NIR absorbing material. Our results show that covellite (CuS exhibits NIR absorption due to its metal-like plasma oscillation in the NIR range.

  10. Near-infrared radiation absorption properties of covellite (CuS) using first-principles calculations

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Lihua, E-mail: xiaolihua@git.edu.cn [School of Materials and Metallurgical Engineering, Guizhou Institute of Technology, Guiyang 550003 (China); College of Physics and Information Science, Hunan Normal University, Changsha 410081 (China); Guizhou Special Functional Materials 2011 Collaborative Innovation Center, Guizhou Institute of Technology, Guiyang 550003 (China); Wu, Jianming; Liu, Yike; Lu, Fanghai [School of Materials and Metallurgical Engineering, Guizhou Institute of Technology, Guiyang 550003 (China); Guizhou Special Functional Materials 2011 Collaborative Innovation Center, Guizhou Institute of Technology, Guiyang 550003 (China); Ran, Jingyu; Qiu, Wei; Shao, Fang [Guizhou Special Functional Materials 2011 Collaborative Innovation Center, Guizhou Institute of Technology, Guiyang 550003 (China); Tang, Dongsheng, E-mail: dstang@hunnu.edu.cn [College of Physics and Information Science, Hunan Normal University, Changsha 410081 (China); Peng, Ping [School of Materials Science and Engineering, Hunan University, Changsha, Hunan 410082 (China)

    2016-08-15

    First-principles density functional theory was used to investigate the electronic structure, optical properties and the origin of the near-infrared (NIR) absorption of covellite (CuS). The calculated lattice constant and optical properties are found to be in reasonable agreement with experimental and theoretical findings. The electronic structure reveals that the valence and conduction bands of covellite are determined by the Cu 3d and S 3p states. By analyzing its optical properties, we can fully understand the potential of covellite (CuS) as a NIR absorbing material. Our results show that covellite (CuS) exhibits NIR absorption due to its metal-like plasma oscillation in the NIR range.

  11. Radiation modification of the properties of polypropylene/carboxymethyl cellulose blends and their biodegradability

    Indian Academy of Sciences (India)

    A M ABDEL GHAFFAR; H E ALI

    2016-12-01

    Polypropylene (PP)/carboxymethyl cellulose (CMC) blend films were prepared by changing content of CMC in the range of 0–20 wt%. Different analytical techniques such as thermogravimetric analysis (TGA), mechanicaltest and scanning electron microscopy (SEM) were used to investigate some selected properties such as thermal properties, tensile strength, elongation and morphology. Fourier transform infrared spectroscopy (FTIR) was performedto identify the chemical structure of the prepared blend films. The blend film with composition PP/15wt% CMC was selected due to its modified properties rather than other blends. The properties of original and irradiated PP/15wt% CMC blend were investigated. It was found that the swelling behaviour is slightly increased with increasing CMC content and does not exceed 7%. It is observed that for PP/15wt% CMC as irradiation dose increases the mechanical property (tensile strength) is enhanced up to 10 kGy and water resistant increases. The prepared PP/CMC with different concentration blends and the selected irradiated PP/15wt% CMC blend with different doses 0, 5, 10 and 20 kGy were subjected to biodegradation in soil burial tests for 6 months using two different types of soils,namely, agricultural and desert soils. The properties of original PP/CMC blends and irradiated PP/15wt% CMC blend that undergo biodegradation were investigated by mechanical test and SEM. From the study it can be concludedthat there is a possibility of using PP/15wt% CMC blend film irradiated to 10 kGy as a potential candidate for packaging purpose.

  12. Direct radiative forcing properties of atmospheric aerosols over semi-arid region, Anantapur in India.

    Science.gov (United States)

    Kalluri, Raja Obul Reddy; Gugamsetty, Balakrishnaiah; Kotalo, Rama Gopal; Nagireddy, Siva Kumar Reddy; Tandule, Chakradhar Rao; Thotli, Lokeswara Reddy; Rajuru Ramakrishna, Reddy; Surendranair, Suresh Babu

    2016-10-01

    This paper describes the aerosols optical, physical characteristics and the aerosol radiative forcing pertaining to semi-arid region, Anantapur for the period January 2013-December 2014. Collocated measurements of Aerosol Optical Depth (AOD) and Black Carbon mass concentration (BC) are carried out by using MICROTOPS II and Aethalometer and estimated the aerosol radiative forcing over this location. The mean values of AOD at 500nm are found to be 0.47±0.09, 0.34±0.08, 0.29±0.06 and 0.30±0.07 during summer, winter, monsoon and post-monsoon respectively. The Angstrom exponent (α380-1020) value is observed maximum in March (1.25±0.19) and which indicates the predominance of fine - mode aerosols and lowest in the month of July (0.33±0.14) and may be due to the dominance of coarse-mode aerosols. The diurnal variation of BC is exhibited two height peaks during morning 07:00-08:00 (IST) and evening 19:00-21:00 (IST) hours and one minima noticed during afternoon (13:00-16:00). The highest monthly mean BC concentration is observed in the month of January (3.4±1.2μgm(-3)) and the lowest in July (1.1±0.2μgm(-3)). The estimated Aerosol Direct Radiative Forcing (ADRF) in the atmosphere is found to be +36.8±1.7Wm(-2), +26.9±0.2Wm(-2), +18.0±0.6Wm(-2) and +18.5±3.1Wm(-2) during summer, winter, monsoon and post-monsoon seasons, respectively. Large difference between TOA and BOA forcing is observed during summer which indicate the large absorption of radiant energy (36.80Wm(-2)) which contributes more increase in atmospheric heating by ~1K/day. The BC contribution on an average is found to be 64% and is responsible for aerosol atmospheric heating.

  13. THE INVESTIGATION OF INFLUENCE OF LASER RADIATION ON THE STRUCTURE AND MECHANICAL PROPERTIES OF COMPOSITE ELECTROLYTIC NICKEL COATING

    Directory of Open Access Journals (Sweden)

    V. A. Zabludovsky

    2013-09-01

    Full Text Available Purpose. Investigation of laser radiation effect on the structure and mechanical properties of electrodeposited nickel composite coatings containing ultrafine diamonds. Methodology. Electrodeposition of nickel films was carried out with the addition of a standard solution of ultrafine diamonds (UFD on laser-electrolytic installation, built on the basis of the gas-discharge CO2 laser. Mechanical testing the durability of coatings were performed on a machine with reciprocating samples in conditions of dry friction against steel. The spectral microanalysis of the elemental composition of the film - substrate was performed on REMMA-102-02. Findings. Research of nickel coatings and modified ultrafine diamond electrodeposited under external stimulation laser demonstrated the dependence of the structure and mechanical properties of composite electrolytic coating (CEC, and the qualitative and quantitative distribution of nanodiamond coprecipitated from an electrodeposition method. Originality. The effect of laser light on the process of co-precipitation of the UFD, which increases the micro-hardness and wear resistance of electrolytic nickel coatings was determined. Practical value. The test method of laser-stimulated composite electrolytic nickel electrodeposition coating is an effective method of local increase in wear resistance of metal coatings, which provides durability save performance (functional properties of the surface.

  14. A Bridge from Optical to Infrared Galaxies Explaining Local Properties, Predicting Galaxy Counts and the Cosmic Background Radiation

    CERN Document Server

    Totani, T; Totani, Tomonori; Takeuchi, Tsutomu T.

    2002-01-01

    We give an explanation for the origin of various properties observed in local infrared galaxies, and make predictions for galaxy counts and cosmic background radiation (CBR), by a new model extended from that for optical/near-infrared galaxies. Important new characteristics of this study are that (1) mass scale dependence of dust extinction is introduced based on the size-luminosity relation of optical galaxies, and that (2) the big grain dust temperature T_dust is calculated based on a physical consideration for energy balance, rather than using the empirical relation between T_dust and total infrared luminosity L_IR found in local galaxies, which has been employed in most of previous works. Consequently, the local properties of infrared galaxies, i.e., optical/infrared luminosity ratios, L_IR-T_dust correlation, and infrared luminosity function are outputs predicted by the model. Our model indeed reproduces these local properties reasonably well. We then found considerably different results for MIR-submm co...

  15. Correlation between radiation damage and magnetic properties in reactor vessel steels

    Energy Technology Data Exchange (ETDEWEB)

    Kempf, R.A., E-mail: kempf@cnea.gov.ar [División Caracterización, GCCN, CAC-CNEA (Argentina); Sacanell, J. [Departamento Física de la Materia Condensada, GIyA, CAC-CNEA, CONICET (Argentina); Milano, J. [División Resonancias Magnéticas, CAB-CNEA, CONICET (Argentina); Guerra Méndez, N. [Departamento Física de la Materia Condensada, GIyA, CAC-CNEA, CONICET (Argentina); Winkler, E.; Butera, A. [División Resonancias Magnéticas, CAB-CNEA, CONICET (Argentina); Troiani, H. [División Física de Metales, CAB-CNEA and Instituto Balseiro (UNCU), CONICET (Argentina); Saleta, M.E. [División Resonancias Magnéticas, CAB-CNEA, CONICET (Argentina); Fortis, A.M. [Departamento Estructura y Comportamiento. Gerencia Materiales-GAEN, CAC-CNEA (Argentina)

    2014-02-01

    Since reactor pressure vessel steels are ferromagnetic, provide a convenient means to monitor changes in the mechanical properties of the material upon irradiation with high energy particles, by measuring their magnetic properties. Here, we discuss the correlation between mechanical and magnetic properties and microstructure, by studying the flux effect on the nuclear pressure vessel steel used in reactors currently under construction in Argentina. Charpy-V notched specimens of this steel were irradiated in the RA1 experimental reactor at 275 °C with two lead factors (LFs), 93 and 183. The magnetic properties were studied by means of DC magnetometry and ferromagnetic resonance. The results show that the coercive field and magnetic anisotropy spatial distribution are sensitive to the LF and can be explained by taking into account the evolution of the microstructure with this parameter. The saturation magnetization shows a dominant dependence on the accumulated damage. Consequently, the mentioned techniques are suitable to estimate the degradation of the reactor vessel steel.

  16. Study of \\chi_{bJ}(1P) Properties in the Radiative \\Upsilon(2S) Decays

    CERN Document Server

    Abdesselam, A; Adamczyk, K; Aihara, H; Said, S Al; Arinstein, K; Arita, Y; Asner, D M; Aso, T; Atmacan, H; Aulchenko, V; Aushev, T; Ayad, R; Aziz, T; Babu, V; Badhrees, I; Bahinipati, S; Bakich, A M; Bala, A; Ban, Y; Bansal, V; Barberio, E; Barrett, M; Bartel, W; Bay, A; Bedny, I; Behera, P; Belhorn, M; Belous, K; Berger, M; Besson, D; Bhardwaj, V; Bhuyan, B; Biswal, J; Bloomfield, T; Blyth, S; Bobrov, A; Bondar, A; Bonvicini, G; Bookwalter, C; Boulahouache, C; Bozek, A; Bračko, M; Breibeck, F; Brodzicka, J; Browder, T E; Waheed, E; Červenkov, D; Chang, M -C; Chang, P; Chao, Y; Chekelian, V; Chen, A; Chen, K -F; Chen, P; Cheon, B G; Chilikin, K; Chistov, R; Cho, K; Chobanova, V; Choi, S -K; Choi, Y; Cinabro, D; Crnkovic, J; Dalseno, J; Danilov, M; Dash, N; Di Carlo, S; Dingfelder, J; Doležal, Z; Dossett, D; Drásal, Z; Drutskoy, A; Dubey, S; Dutta, D; Dutta, K; Eidelman, S; Epifanov, D; Esen, S; Farhat, H; Fast, J E; Feindt, M; Ferber, T; Frey, A; Frost, O; Fulsom, B G; Gaur, V; Gabyshev, N; Ganguly, S; Garmash, A; Getzkow, D; Gillard, R; Giordano, F; Glattauer, R; Goh, Y M; Goldenzweig, P; Golob, B; Greenwald, D; Perdekamp, M Grosse; Grygier, J; Grzymkowska, O; Guo, H; Haba, J; Hamer, P; Han, Y L; Hara, K; Hara, T; Hasegawa, Y; Hasenbusch, J; Hayasaka, K; Hayashii, H; He, X H; Heck, M; Hedges, M T; Heffernan, D; Heider, M; Heller, A; Higuchi, T; Himori, S; Hirose, S; Horiguchi, T; Hoshi, Y; Hoshina, K; Hou, W -S; Hsiung, Y B; Hsu, C -L; Huschle, M; Hyun, H J; Igarashi, Y; Iijima, T; Imamura, M; Inami, K; Inguglia, G; Ishikawa, A; Itagaki, K; Itoh, R; Iwabuchi, M; Iwasaki, M; Iwasaki, Y; Iwata, S; Jacobs, W W; Jaegle, I; Jeon, H B; Joffe, D; Jones, M; Joo, K K; Julius, T; Kakuno, H; Kang, J H; Kang, K H; Kapusta, P; Kataoka, S U; Kato, E; Kato, Y; Katrenko, P; Kawai, H; Kawasaki, T; Keck, T; Kichimi, H; Kiesling, C; Kim, B H; Kim, D Y; Kim, H J; Kim, H -J; Kim, J B; Kim, J H; Kim, K T; Kim, M J; Kim, S H; Kim, S K; Kim, Y J; Kinoshita, K; Kleinwort, C; Klucar, J; Ko, B R; Kobayashi, N; Koblitz, S; Kodyš, P; Koga, Y; Korpar, S; Kotchetkov, D; Kouzes, R T; Križan, P; Krokovny, P; Kronenbitter, B; Kuhr, T; Kulasiri, L; Kumar, R; Kumita, T; Kurihara, E; Kuroki, Y; Kuzmin, A; Kvasnička, P; Kwon, Y -J; Lai, Y -T; Lange, J S; Lee, D H; Lee, I S; Lee, S -H; Leitgab, M; Leitner, R; Levit, D; Lewis, P; Li, C H; Li, H; Li, J; Li, L; Li, X; Li, Y; Gioi, L Li; Libby, J; Limosani, A; Liu, C; Liu, Y; Liu, Z Q; Liventsev, D; Loos, A; Louvot, R; Lubej, M; Lukin, P; Luo, T; MacNaughton, J; Masuda, M; Matsuda, T; Matvienko, D; Matyja, A; McOnie, S; Mikami, Y; Miyabayashi, K; Miyachi, Y; Miyake, H; Miyata, H; Miyazaki, Y; Mizuk, R; Mohanty, G B; Mohanty, S; Mohapatra, D; Moll, A; Moon, H K; Mori, T; Morii, T; Moser, H -G; Müller, T; Muramatsu, N; Mussa, R; Nagamine, T; Nagasaka, Y; Nakahama, Y; Nakamura, I; Nakamura, K R; Nakano, E; Nakano, H; Nakano, T; Nakao, M; Nakayama, H; Nakazawa, H; Nanut, T; Nath, K J; Natkaniec, Z; Nayak, M; Nedelkovska, E; Negishi, K; Neichi, K; Ng, C; Niebuhr, C; Niiyama, M; Nisar, N K; Nishida, S; Nishimura, K; Nitoh, O; Nozaki, T; Ogawa, A; Ogawa, S; Ohshima, T; Okuno, S; Olsen, S L; Ono, Y; Onuki, Y; Ostrowicz, W; Oswald, C; Ozaki, H; Pakhlov, P; Pakhlova, G; Pal, B; Palka, H; Panzenböck, E; Park, C -S; Park, C W; Park, H; Park, K S; Paul, S; Peak, L S; Pedlar, T K; Peng, T; Pesántez, L; Pestotnik, R; Peters, M; Petrič, M; Piilonen, L E; Poluektov, A; Prasanth, K; Prim, M; Prothmann, K; Pulvermacher, C; Purohit, M V; Rauch, J; Reisert, B; Ribežl, E; Ritter, M; Röhrken, M; Rorie, J; Rostomyan, A; Rozanska, M; Rummel, S; Ryu, S; Sahoo, H; Saito, T; Sakai, K; Sakai, Y; Sandilya, S; Santel, D; Santelj, L; Sanuki, T; Sasao, N; Sato, Y; Savinov, V; Schlüter, T; Schneider, O; Schnell, G; Schönmeier, P; Schram, M; Schwanda, C; Schwartz, A J; Schwenker, B; Seidl, R; Seino, Y; Semmler, D; Senyo, K; Seon, O; Seong, I S; Sevior, M E; Shang, L; Shapkin, M; Shebalin, V; Shen, C P; Shibata, T -A; Shibuya, H; Shinomiya, S; Shiu, J -G; Shwartz, B; Sibidanov, A; Simon, F; Singh, J B; Sinha, R; Smerkol, P; Sohn, Y -S; Sokolov, A; Soloviev, Y; Solovieva, E; Stanič, S; Starič, M; Steder, M; Strube, J F; Stypula, J; Sugihara, S; Sugiyama, A; Sumihama, M; Sumisawa, K; Sumiyoshi, T; Suzuki, K; Suzuki, K; Suzuki, S; Suzuki, S Y; Suzuki, Z; Takeichi, H; Takizawa, M; Tamponi, U; Tanaka, M; Tanaka, S; Tanida, K; Taniguchi, N; Taylor, G N; Tenchini, F; Teramoto, Y; Tikhomirov, I; Trabelsi, K; Trusov, V; Tse, Y F; Tsuboyama, T; Uchida, M; Uchida, T; Uehara, S; Ueno, K; Uglov, T; Unno, Y; Uno, S; Uozumi, S; Urquijo, P; Ushiroda, Y; Usov, Y; Vahsen, S E; Van Hulse, C; Vanhoefer, P; Varner, G; Varvell, K E; Vervink, K; Vinokurova, A; Vorobyev, V; Vossen, A; Wagner, M N; Waheed, E; Wang, C H; Wang, J; Wang, M -Z; Wang, P; Wang, X L; Watanabe, M; Watanabe, Y; Wedd, R; Wehle, S; White, E; Widmann, E; Wiechczynski, J; Williams, K M; Won, E; Yabsley, B D; Yamada, S; Yamamoto, H; Yamaoka, J; Yamashita, Y; Yamauchi, M; Yashchenko, S; Ye, H; Yelton, J; Yook, Y; Yuan, C Z; Yusa, Y; Zhang, C C; Zhang, L M; Zhang, Z P; Zhao, L; Zhilich, V; Zhukova, V; Zhulanov, V; Ziegler, M; Zivko, T; Zupanc, A; Zwahlen, N; Zyukova, O

    2016-01-01

    We report a study of radiative decays of \\chi_{bJ}(1P)(J=0,1,2) mesons into 74 hadronic final states comprising charged and neutral pions, kaons, protons; out of these, 41 modes are observed with at least 5 standard deviation significance. Our measurements not only improve the previous measurements by the CLEO Collaboration but also lead to first observations in many new modes. The large sample allows us to probe the total decay width of the \\chi_{b0}(1P). In the absence of a statistically significant result, a 90% confidence-level upper limit is set on the width at \\Gamma_{total}< 2.4 MeV. Our results are based on 24.7 fb^{-1} of e+e- collision data recorded by the Belle detector at the \\Upsilon(2S) resonance, corresponding to (157.8\\pm3.6)\\times10^6 \\Upsilon(2S) decays.

  17. Measurement of Elastic Properties of Tissue by Shear Wave Propagation Generated by Acoustic Radiation Force

    Science.gov (United States)

    Tabaru, Marie; Azuma, Takashi; Hashiba, Kunio

    2010-07-01

    Acoustic radiation force (ARF) imaging has been developed as a novel elastography technology to diagnose hepatic disease and breast cancer. The accuracy of shear wave speed estimation, which is one of the applications of ARF elastography, is studied. The Young's moduli of pig liver and foie gras samples estimated from the shear wave speed were compared with those measured the static Young's modulus measurement. The difference in the two methods was 8%. Distance attenuation characteristics of the shear wave were also studied using finite element method (FEM) analysis. We found that the differences in the axial and lateral beam widths in pressure and ARF are 16 and 9% at F-number=0.9. We studied the relationship between two branch points in distance attenuation characteristics and the shape of ARF. We found that the maximum measurable length to estimate shear wave speed for one ARF excitation was 8 mm.

  18. Entropy and complexity properties of the d-dimensional blackbody radiation

    CERN Document Server

    Toranzo, I V

    2015-01-01

    Space dimensionality is a crucial variable in the analysis of the structure and dynamics of natural systems and phenomena. The dimensionality effects of the blackbody radiation has been the subject of considerable research activity in recent years. These studies are still somewhat fragmentary, pos- ing formidable qualitative and quantitative problems for various scientific and technological areas. In this work we carry out an information-theoretical analysis of the spectral energy density of a d-dimensional blackbody at temperature T by means of various entropy-like quantities (disequilibrium, Shannon entropy, Fisher information) as well as by three (dimensionless) complexity measures (Cr\\'amer-Rao, Fisher-Shannon and LMC). All these frequency-functional quantities are calculated and discussed in terms of temperature and dimensionality. It is shown that all three measures of complexity have an universal character in the sense that they depend neither on temperature nor on the Planck and Boltzmann constants, b...

  19. Thermal radiation effect on the extinction properties of electric arcs in HV circuit breakers

    Directory of Open Access Journals (Sweden)

    Ziani Abderrahmane

    2009-01-01

    Full Text Available During the formation of the electric arc at the opening of a high voltage circuit breaker, the generated plasma will be the seat of a very important thermal exchange. Models founded only on conduction and convection thermal transfers don't reproduce the whole thermal exchanges that are governing the extinction process. This paper is devoted to the development of a model of the electric arc extinction in a high voltage circuit breaker taking in account the thermal radiation of the plasma, in addition to the conduction and convection phenomena. The Stefan-Boltzman equation is coupled with the heat equation, and both equations are solved simultaneously in order to follow the evolution of the arc voltage and the conductance of the thermal plasma. The obtained results are found in good agreement with experimental recordings.

  20. Properties of cold ions produced by synchrotron radiation and by charged particle impact

    Science.gov (United States)

    Levin, J. C.; Biedermann, C.; Cederquist, H.; O, C.-S.; Short, R. T.; Sellin, I. A.

    1989-04-01

    Argon recoil ions produced by beams of 0.8 MeV/u Cl 5+ have been detected by time-of-flight (TOF) techniques in coincidence with the loss of from one to five projectile electrons. Recoil-ion energies have been determined to be more than an order of magnitude higher than those of highly charged ions produced by unmonochromatized synchrotron radiation. Charge-state distributions, however, show similarities, suggesting that loss of projectile electrons corresponds, in some cases, to inner-shell target ionization producing vacancy cascades. In an essential improvement to the usual multinomial description of ionization in the independent-electron-ejection model, we find the inclusion of Auger vacancy cascades significantly alters the description of the recoil ion spectra corresponding to the projectile-electron loss. These conclusions are consistent with impact parameters inferred from determination of mean recoil energy.

  1. Effects of nuclear radiation on the optical properties of cerium-doped glass (accelerator applications)

    CERN Document Server

    McGrath, B; Van de Voorde, M H

    1976-01-01

    Some twenty types of glass containing 0.5-4% CeO/sub 2/ have been irradiated in a /sup 60/Co gamma cell and in the mixed neutron-gamma field of a nuclear reactor, at total integrated doses of up to 5*10 /sup 9/ rad (CH). The resulting colouration has been assessed quantitatively by measuring the light transmission with reference to air, in the range 360-510 nm. From the results, certain types of glass suitable for applications in nuclear engineering can be selected. Specifically, it was found that 1-2% CeO/sub 2/ content is usually sufficient to obtain radiation-resistant optical glass: the reduction in light transmission above 450 nm is nil at 10/sup 8/ rad (CH), below 10% at 10/sup 9/ rad (CH), and below 20% at 5*10/sup 9/ rad (CH); the post-irradiation fading is negligible.

  2. Scintillation properties of semiconducting 6LiInSe2 crystals to ionizing radiation

    Science.gov (United States)

    Wiggins, Brenden; Groza, Michael; Tupitsyn, Eugene; Lukosi, Eric; Stassun, Keivan; Burger, Arnold; Stowe, Ashley

    2015-11-01

    6LiInSe2 has gained attention recently as a semiconducting thermal neutron detector. As presented herein, the chalcogenide compound semiconductor also detects incident neutrons via scintillation, making 6LiInSe2 the only lithium containing semiconductor to respond to neutrons via both detection mechanisms. Both yellow and red crystals, which appear in the literature, were investigated. Only the yellow crystal responded favorably to ionizing radiation, similar to the semiconducting operation utilizing electrodes. The obtained light yield for yellow crystals is 4400 photons/MeV, referenced to Bi4Ge3O12 (BGO).The estimated thermal neutron light yield was 21,000 photons/thermal neutron. The two measured decay time components were found to be 31±1 ns (49%) and 143±9 ns (51%).This crystal provides efficient, robust detection of neutrons via scintillation with respectable light yield and rapid response, enabling its use for a broad array of neutron detection applications.

  3. Effects of high energy radiation on the mechanical properties of epoxy/graphite fiber reinforced composites

    Science.gov (United States)

    Fornes, R. E.; Gilbert, R. D.; Memory, J. D.

    1987-01-01

    Publications and theses generated on composite research are listed. Surface energy changes of an epoxy based on tetraglycidyl diaminodiphenyl methane (TGDDM)/diaminodiphenyl sulfone (DDS), T-300 graphite fiber and T-300/5208 (graphite fiber/epoxy) composites were investigated after irradiation with 0.5 MeV electrons. Electron spin resonance (ESR) investigations of line shapes and the radical decay behavior were made of an epoxy based on tetraglycidyl diaminodiphenyl methane (TGDDM)/diaminodiphenyl sulfone (DDS), T-300 graphite fiber, and T-300/5208 (graphite fiber/epoxy) composites after irradiation with Co(60) gamma-radiation or 0.5 MeV electrons. The results of the experiments are discussed.

  4. Effects of Trehalose on Thermodynamic Properties of Alpha-synuclein Revealed through Synchrotron Radiation Circular Dichroism

    Science.gov (United States)

    Ruzza, Paolo; Hussain, Rohanah; Biondi, Barbara; Calderan, Andrea; Tessari, Isabella; Bubacco, Luigi; Siligardi, Giuliano

    2015-01-01

    Many neurodegenerative diseases, including Huntington’s, Alzheimer’s and Parkinson’s diseases, are characterized by protein misfolding and aggregation. The capability of trehalose to interfere with protein misfolding and aggregation has been recently evaluated by several research groups. In the present work, we studied, by means of synchrotron radiation circular dichroism (SRCD) spectroscopy, the dose-effect of trehalose on α-synuclein conformation and/or stability to probe the capability of this osmolyte to interfere with α-synuclein’s aggregation. Our study indicated that a low trehalose concentration stabilized α-synuclein folding much better than at high concentration by blocking in vitro α-synuclein’s polymerisation. These results suggested that trehalose could be associated with other drugs leading to a new approach for treating Parkinson’s and other brain-related diseases. PMID:25946077

  5. Effects of Trehalose on Thermodynamic Properties of Alpha-synuclein Revealed through Synchrotron Radiation Circular Dichroism

    Directory of Open Access Journals (Sweden)

    Paolo Ruzza

    2015-05-01

    Full Text Available Many neurodegenerative diseases, including Huntington’s, Alzheimer’s and Parkinson’s diseases, are characterized by protein misfolding and aggregation. The capability of trehalose to interfere with protein misfolding and aggregation has been recently evaluated by several research groups. In the present work, we studied, by means of synchrotron radiation circular dichroism (SRCD spectroscopy, the dose-effect of trehalose on α-synuclein conformation and/or stability to probe the capability of this osmolyte to interfere with α-synuclein’s aggregation. Our study indicated that a low trehalose concentration stabilized α-synuclein folding much better than at high concentration by blocking in vitro α-synuclein’s polymerisation. These results suggested that trehalose could be associated with other drugs leading to a new approach for treating Parkinson’s and other brain-related diseases.

  6. Studies of Mn/ZnO (0001¯) Interfacial Formation and Electronic Properties with Synchrotron Radiation

    Science.gov (United States)

    Zou, C. W.; Xu, P. S.; Wu, Y. Y.; Sun, B.; Xu, F. Q.; Pan, H. B.; Yuan, H. T.; Du, X. L.

    2007-01-01

    The initial growth, interfacial reaction and Fermi level movement of Mn on the O-terminated Zn (000 1¯) surface have been investigated by using synchrotron radiation photoelectron spectroscopy (SRPES) and X-ray photoemission (XPS). Mn is found to be grown on the surface in the layer-by-layer (Frank-van der Merwe) mode and be quite stable on the O-terminated surface at room temperature. With increasing the coverage of Mn, a downward Fermi level movement in band structure measurement of SRPES is observed and the resultant Schottky Barrier Height (SBH) is calculated to be about 1.1eV. Annealing behavior of the interface is investigated and we find that annealing at 600 °C induces a pronounced Mn-Zn atoms exchange reaction at the interface.

  7. Radiation on luminescent properties of quartz glasses and fiber light pipes

    CERN Document Server

    Abdurakhmanov, B S; Gulamova, R R; Alimov, R; Yuldashev, B S; Ashurov, M K; Rustamov, I R

    2002-01-01

    Paper contains the results of investigation into X-ray luminescence of KI and KU-1 quartz glasses and of various composition and size quartz fiber light pipes (FLP) gamma-irradiated within 10 sup 2 -10 sup 7 Gy dose range. On the basis of analysis of X-ray luminescence spectra of glasses and FLP and comparison of the experimental data one detected in spectra two luminescence bands within 410, 450-470 nm range. One determined dose dependences of X-ray luminescence intensity of every of these bands of luminescence and hypothesized about the nature of the relevant centers. The protective role of OH-groups in the process of radiation-induced generation of luminescence centres under gamma-irradiation of quartz glasses and FLP was confirmed experimentally

  8. Polar solar wind and interstellar wind properties from interplanetary Lyman-alpha radiation measurements

    Science.gov (United States)

    Witt, N.; Blum, P. W.; Ajello, J. M.

    1981-01-01

    The analysis of Mariner 10 observations of Lyman-alpha resonance radiation shows an increase of interplanetary neutral hydrogen densities above the solar poles. This increase is caused by a latitudinal variation of the solar wind velocity and/or flux. Using both the Mariner 10 results and other solar wind observations, the values of the solar wind flux and velocity with latitude are determined for several cases of interest. The latitudinal variation of interplanetary hydrogen gas, arising from the solar wind latitudinal variation, is shown to be most pronounced in the inner solar system. From this result it is shown that spacecraft Lyman-alpha observations are more sensitive to the latitudinal anisotropy for a spacecraft location in the inner solar system near the downwind axis.

  9. Estimation of participating media radiative properties with time dependent external illumination

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez Acevedo, Nancy I. [Universidade do Estado, Nova Friburgo, RJ (Brazil). Instituto Politecnico. Dept. de Modelagem Computacional]. E-mail: nacevedo@iprj.uerj.br; Roberty, Nilson C.; Silva Neto, Antonio J. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia. Programa de Engenharia Nuclear]. E-mail: nilson@lmn.con.ufrj.br; ajsneto@lmn.con.ufrj.br; ajsneto@iprj.uerj.br

    2003-07-01

    In this work two methods for the absorption and scattering coefficients estimation in homogeneous participant media with transient data on the intensity of the radiation that leaves of the medium are investigated. The transient problem is reduced to a family of stationary problems with an absorption coefficient modified by Laplace's transform parameter s. The transient experimental data acquired at the boundaries of the medium are also Laplace transformed and the inverse problem is then solved in the transformed space. The source-detector methodology and Levenberg-Marquardt's method, are applied to investigate the simultaneous estimation of the total extinction and scattering coefficients. numerical test cases results are presented. (author)

  10. Radiation-resistant properties of Ga-doped Si analyzed by DLTS

    Energy Technology Data Exchange (ETDEWEB)

    Yamaguchi, M.; Khan, A.; Vu, T.K.; Ohshita, Y.; Abe, T

    2003-12-31

    Using deep-level transient spectroscopy (DLTS), we have studied the effect of Ga impurities upon defect generation and annealing behavior of radiation-induced defects, and carrier removal and minority-carrier lifetime degradation in Si single crystals irradiated with 1 MeV electrons at room temperature. It is found that compared to the B impurity in p-type Si, the Ga impurity strongly suppresses the generation of the E{sub C}-0.18-0.21 eV and E{sub V}+0.36 eV defect centers, which play a dominant role in carrier removal as a deep donor state and act as a majority-carrier trapping center, and a recombination center. The effectiveness of the Ga impurity for suppressing the carrier removal effect with irradiation is also found in comparison to the B impurity.

  11. Radiation-resistant properties of Ga-doped Si analyzed by DLTS

    Science.gov (United States)

    Yamaguchi, M.; Khan, A.; Vu, T. K.; Ohshita, Y.; Abe, T.

    2003-12-01

    Using deep-level transient spectroscopy (DLTS), we have studied the effect of Ga impurities upon defect generation and annealing behavior of radiation-induced defects, and carrier removal and minority-carrier lifetime degradation in Si single crystals irradiated with 1 MeV electrons at room temperature. It is found that compared to the B impurity in p-type Si, the Ga impurity strongly suppresses the generation of the EC-0.18-0.21 eV and EV+0.36 eV defect centers, which play a dominant role in carrier removal as a deep donor state and act as a majority-carrier trapping center, and a recombination center. The effectiveness of the Ga impurity for suppressing the carrier removal effect with irradiation is also found in comparison to the B impurity.

  12. Radiative and convective properties of 316L Stainless Steel fabricated using the Laser Engineered Net Shaping process

    Science.gov (United States)

    Knopp, Jonathan

    Temperature evolution of metallic materials during the additive manufacturing process has direct influence in determining the materials microstructure and resultant characteristics. Through the power of Infrared (IR) thermography it is now possible to monitor thermal trends in a build structure, giving the power to adjust building parameters in real time. The IR camera views radiation in the IR wavelengths and determines temperature of an object by the amount of radiation emitted from the object in those wavelengths. Determining the amount of radiation emitted from the material, known as a materials emissivity, can be difficult in that emissivity is affected by both temperature and surface finish. It has been shown that the use of a micro-blackbody cavity can be used as an accurate reference temperature when the sample is held at thermal equilibrium. A micro-blackbody cavity was created in a sample of 316L Stainless Steel after being fabricated during using the Laser Engineered Net Shaping (LENS) process. Holding the sample at thermal equilibrium and using the micro-blackbody cavity as a reference and thermocouple as a second reference emissivity values were able to be obtained. IR thermography was also used to observe the manufacturing of these samples. When observing the IR thermography, patterns in the thermal history of the build were shown to be present as well as distinct cooling rates of the material. This information can be used to find true temperatures of 316L Stainless Steel during the LENS process for better control of desired material properties as well as future work in determining complete energy balance.

  13. Effect of ultraviolet and x-ray radiation on optical properties of epoxy polymers dyed with organic phosphors

    Science.gov (United States)

    Laurinas, V. CH; Kasymov, S. S.; Yurov, V. M.; Eremin, E. N.; Vedyashkin, M. V.

    2017-01-01

    Highly purified industrial bisphenol and cycloaliphatic epoxy oligomers of ED-24 and UP-612 brands were used to produce optically transparent products. UV radiation of a low-pressure mercury lamp with 80% of the light energy at 254 nm was used to study photodegradation. X-ray apparatus with 0.7BSV- Ag tube was used as an ionizing radiation source to investigate the effect of X-rays on the spectra of organic dyes in epoxy polymer. The threshold value of the energy generated by ruby laser which indicated the degradation in the test samples recorded by light scattering method was determined to study radiation resistance of epoxy polymers. Basically, all the dyes exhibited high resistance to UV light. The observation of the absorption spectra showed that on average, a third of the dye molecules in the matrix experienced photobleaching within 200 hour exposure. The exception was coumarin 1, which was completely decolourized after 40 hours of exposure. X-ray irradiation of the samples for two hours results in the change in the optical density equivalent to that caused by 40 hour exposure to UV irradiation. However, in the first case, the matrix optical density is proportional to the irradiation time, and in the second case, it remains stable upon further UV irradiation. The comparison of photoaging processes in dyed and undyed epoxy polymers showed that the investigated organic dyes do not have a sensitizing effect on the matrix. The stability of the optical properties of the epoxy matrices exposed to the effects of different factors was found to depend on the nature of epoxy polymer and the technique of its production. The results of these effects are significantly different in the character of the change in the optical density and mechanisms of chemical transformations in polymer.

  14. Accounting for particle non-sphericity in modeling of mineral dust radiative properties in the thermal infrared

    Science.gov (United States)

    Legrand, M.; Dubovik, O.; Lapyonok, T.; Derimian, Y.

    2014-12-01

    Spectral radiative parameters (extinction optical depth, single scattering albedo, asymmetry factor) of spheroids of mineral dust composed of quartz and clays have been simulated at wavelengths between 7.0 and 10.2 μm using a T-matrix code. In spectral intervals with high values of complex index of refraction and for large particles, the parameters cannot be fully calculated with the code. Practically, the calculations are stopped at a truncation radius over which the particles contribution cannot thus be taken into account. To deal with this issue, we have developed and applied an accurate corrective technique of T-matrix Size Truncation Compensation (TSTC). For a mineral dust described by its AERONET standard aspect ratio (AR) distribution, the full error margin when applying the TSTC is within 0.3% (or ±0.15%), whatever the radiative parameter and the wavelength considered, for quartz (the most difficult case). Large AR values limit also the possibilities of calculation with the code. The TSTC has been able to complete the calculations of the T-matrix code for a modified AERONET AR distribution with a maximum AR of 4.7 instead of 3 for the standard distribution. Comparison between the simulated properties of spheroids and of spheres of same volume confirms, in agreement with the literature, that significant differences are observed in the vicinity of the mineral resonant peaks (λ ca. 8.3-8.7 μm for quartz, ca. 9.3-9.5 μm for clays) and that they are due to absorption by the small particles. This is a favorable circumstance for the TSTC, which is concerned with the contribution of the largest particles. This technique of numerical calculation improves the accuracy of the simulated radiative parameters of mineral dust, which must lead to a progress in view of applications such as remote sensing or determination of energy balance of dust in the thermal infrared (TIR), incompletely investigated so far.

  15. Identification of aerosol types over Indo-Gangetic Basin: implications to optical properties and associated radiative forcing.

    Science.gov (United States)

    Tiwari, S; Srivastava, A K; Singh, A K; Singh, Sachchidanand

    2015-08-01

    The aerosols in the Indo-Gangetic Basin (IGB) are a mixture of sulfate, dust, black carbon, and other soluble and insoluble components. It is a challenge not only to identify these various aerosol types, but also to assess the optical and radiative implications of these components. In the present study, appropriate thresholds for fine-mode fraction and single-scattering albedo have been used to first identify the aerosol types over IGB. Four major aerosol types may be identified as polluted dust (PD), polluted continental (PC), black carbon-enriched (BCE), and organic carbon-enriched (OCE). Further, the implications of these different types of aerosols on optical properties and radiative forcing have been studied. The aerosol products derived from CIMEL sun/sky radiometer measurements, deployed under Aerosol Robotic Network program of NASA, USA were used from four different sites Karachi, Lahore, Jaipur, and Kanpur, spread over Pakistan and Northern India. PD is the most dominant aerosol type at Karachi and Jaipur, contributing more than 50% of all the aerosol types. OCE, on the other hand, contributes only about 12-15% at all the stations except at Kanpur where its contribution is ∼38%. The spectral dependence of AOD was relatively low for PD aerosol type, with the lowest AE values (1.0). SSA was found to be the highest for OCE (>0.9) and the lowest for BCE (<0.9) type aerosols, with drastically different spectral variability. The direct aerosol radiative forcing at the surface and in the atmosphere was found to be the maximum at Lahore among all the four stations in the IGB.

  16. Radiation effects on rat testes. VIII. Kinetic properties of hydrolases following partial body gamma irradiation of rats.

    Science.gov (United States)

    Gupta, G S; Bawa, S R

    1975-05-01

    Kinetic properties such as Michaelis constant (Km), maximum velocity (Vmax), temperature coefficient (Q10) and energy of activation (Ea) for hydrolysis of adenosine-5'-phosphate at pH 9.5 and sodium pyrophosphate at pH 8.35 by normal and radiated testes supernatants have been described. Kinetic parameters are related to respective phosphohydrolases (phosphatases). (1) Km values for 5'nucleotidase and inorganic pyrophosphatase of normal testis were determined as 1.25 X 10(-3)M and 0.81 X 10(-3)M respectively; (II) Vmax correspond to 318 mug P/15 min and 430 mug P/15 min for 100 mg tissue respectively; (III) Q10 for 5 nucleotidase is 1.7 and for inorganic pyrophosphatase is 4.2 at a temperature 10-30degreesC; (IV) Ea for hydrolysis of AMP and sodium pyrophosphate were calculated by Arrhenius plots as 17000 and 9000 cal/mol. (V) Km values for irradiated enzymes are similar to the control values suggesting that the binding capacities of these enzymes with their substrates remain unaffected after radiation; (VI) Vmax for radiated enzymes correspond to a value of 500 mug P/100 mg tissue/15 min for 5'nucleotidase and 118 mug P/100 mug tissue/15 min for inorganic pyrophosphatase; (VII) 110 for 5'nucleotidase is 2.2 and inorganic pyrophosphatase 1.16 at 10-30degreesC; (VIII) Ea for irradiated 5'nucleotidase is comparable to those of normal rats whereas for inorganic pyrophosphatase Ea is moderately declined. The observed changes have been related to the different types of metabolic activity in germinal and nongerminal cells of testes.

  17. Effects of gamma radiation on the electric properties of polyaniline; Efeitos da radiacao gama nas propriedades eletricas da polianilina

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Ana Paula da Costa

    1999-03-01

    Polymeric organic conductors has been attracting considerable attention in the scientific community. The possibility of having together the characteristics of conventional polymers with the electrical properties of conductive materials has greatly advanced the field of polymeric conductors in recent years. Among several polymers, polyaniline is the only polymeric conductor that its conductivity controlled by charge transfer doping by chemical or electrochemical oxidation and by protonation doping, without alteration in the number of electrons of the polymeric chain. These processes are reversible, and the conductivity of the polymers vary over orders of magnitude transforming the polymer from an insulator to a conductor. The electric conductivity in organic polymers can be explain by the formation of defects in the polymeric chain. These defects are due to doping process that can be done chemically or electrochemically, in most of polymer they are called solitons, polarons and bipolarons. The movement of the defects along the polymeric chain is responsible for the conductivity of the synthetic metals. The subject of these work is the characterization of electrical conductivity of PANI when the polymer interact with ionizing radiation. The effect of the interaction of gamma radiation with the polymer surface was studied using films chemically prepared in different oxidation states and with different levels of doping in order to evaluated the responses of these films the measurements were done as a function of the radiation dose. Also we develop a model based in the redox process of the main chain together with water radiolysis of absolved water molecule in order to explain the interaction. (author)

  18. Aerosol optical properties and radiative effect determined from sky-radiometer over Loess Plateau of Northwest China

    Directory of Open Access Journals (Sweden)

    Y. Liu

    2011-11-01

    Full Text Available The aerosol optical properties and their associated radiative effects are derived from sky-radiometer and surface solar radiation data collected over the Semi-Arid Climate and Environment Observatory of Lanzhou University (SACOL for the period of March to May (MAM 2009. The result shows that the seasonal mean aerosol optical depth (AOD at 500 nm in MAM is 0.40. The single scattering albedo (SSA at 500 nm in MAM at SACOL fluctuates significantly ranging from 0.82 to 0.98. The averaged value of SSA there for background aerosol is 0.90 in MAM, while it is smaller (0.87 during the dust event outbreak period. The smaller SSA can be interpreted as the result of larger particles during dust events. The averaged asymmetry factor (ASY at 500 nm during dust event period is 0.73, which is larger than 0.70 of background aerosols. The averaged shortwave radiative effects of the aerosols during dust event period in MAM are 0.68, −70.02 and 70.70 W m−2, respectively, at the top of the atmosphere (TOA, surface and in the atmosphere. The aerosols heat the atmosphere during dust event period by up to about 2 K day−1 (daily averaged, which is 60 % larger than the heating (1.25 K day−1 of background aerosols. The significant heating effect in the atmosphere of the aerosols during dust event is determined by larger AOD and smaller SSA.

  19. Radiation attenuation and nuclear properties of high density concrete made with steel aggregates

    Science.gov (United States)

    Bashter, I. I.

    The fast neutron and gamma ray spectra measured behind different thickness of steel scrap concrete with density of 4 g/cm3 have been studied. The mix proportions by weight of this type of concrete were 1 cement: 6.89 steel scrap: 2.9 sand and 0.5 Water. Comparison with a standard ordinary concrete of density 2.3 g/cm3 have been carried out. The measurements were made using a collimated beam of both gamma rays and neutrons emitted from one of the horizontal channel of the Egyptian Research Reactor-1. A fast neutron and gamma ray spectrometer with a stilbene crystal was used to measure the spectra of fast neutrons and gamma rays. Pulse shape discrimination using the zero cross over technique was used to separate the photon pulses from the electron pulses. The equation due to Schmidt has been modified and applied for determining the neutron effective removal cross sections (˜R) for steel scrap, ordinary, hematite-serpentine, ilmenite-limonite and ilmenite concretes. This equation gives results which are in good agreement with the measured values. The derived empirical equation in a previous work to calculate the neutron integral flux behind different thicknesses of different types of concretes, gives good results for steel scrap concrete under investigation comparing with the corresponding experimental data. Total neutron macroscopic cross sections, linear attenuation coefficients for gamma rays and the half-value layers for both radiations at different energies have been obtained for steel scrap concrete and comparing with the corresponding values of ordinary concrete. The results show that steel scrap concrete is better than ordinary, hematite-serpentine, ilmenite-limonite and ilmenite concretes from the radiation shielding point of view.

  20. Ultraviolet radiation-induced modifications of the optical and registration properties of a CR-39 nuclear track detector

    Energy Technology Data Exchange (ETDEWEB)

    Saad, A.F., E-mail: abdallahsaad56@hotmail.com [Physics Department, Faculty of Science, University of Benghazi, Benghazi (Libya); Physics Department, Faculty of Science, Zagazig University, Zagazig (Egypt); Al-Faitory, N.M. [Physics Department, Faculty of Science, University of Benghazi, Benghazi (Libya); Hussein, M. [Physics Department, Faculty of Science, Zagazig University, Zagazig (Egypt); Mohamed, R.A. [Physics Department, Faculty of Science, University of Benghazi, Benghazi (Libya)

    2015-09-15

    The UV–VIS (ultraviolet–visible) spectra and etching characteristics of poly allyl diglycol carbonate (PADC, a form of the CR-39 polymer) detector films after exposure to UV radiation for various times have been studied. Etching experiments were carried out on the UV-exposed CR-39 detectors after alpha particle and fission-fragment irradiation using a {sup 252}Cf source. The bulk and track etch rates were measured using the alpha and fission-fragment track diameters, and the sensitivity and the detection efficiency were also determined. The optical band gap for both indirect and direct transitions was calculated based on the absorption edge of the UV spectra of the pristine and variously UV-exposed detectors. The optical band gap evidently indicates a gradual change in the optical properties of the CR-39 detector that is induced by the UV radiation. This study shows that the UV-exposed CR-39 detectors were demonstrated to be highly sensitive to alpha particles, but proved to be somewhat less sensitive to the fission fragments.

  1. γ-radiation Sensor Using Optical and Electrical Properties of Manganese Phthalocyanine (MnPc Thick Film

    Directory of Open Access Journals (Sweden)

    K. Arshak

    2002-05-01

    Full Text Available Manganese phthaloyanine polymer thick films were fabricated using screenprinting techniques. The optical parameters were obtained from the analysis of the absorption spectra over a wavelength range of 385-900nm. The d.c. electrical measurements were carried out in a range of 0-30 volts. The effects of γ-radiation on the optical and the electrical properties were investigated for dosimetry applications. The optical energy band gaps of these films showed a decrease in their values with the increase in the radiation dose. The electronic transition has changed from direct allowed for the as-printed films (unexposed to γ-rays to indirect allowed for the irradiated samples. Both the as-printed and irradiated Ag/MnPc/Ag devices demonstrated a Schottky conduction mechanism. Both the absorbance and the capacitance of the MnPc thick films displayed a highly consistent linear response to γ-ray exposure.

  2. Radiation cured epoxy acrylate composites based on graphene, graphite oxide and functionalized graphite oxide with enhanced properties.

    Science.gov (United States)

    Guo, Yuqiang; Bao, Chenlu; Song, Lei; Qian, Xiaodong; Yuan, Bihe; Hu, Yuan

    2012-03-01

    Epoxy acrylate (EA) composites containing graphite oxide (GO), graphene and nitrogen-double bond functionalized graphite oxide (FGO) were fabricated using UV-radiation and electron beam radiation via in-situ polymerization. Graphene and FGO were homogenously dispersed in EA matrix and enhanced properties, including thermal stability, flame retardancy, electrical conductivity and reduced deleterious gas releasing in thermo decomposition were obtained. Microscale combustion colorimeter results illustrated improved flame retardancy; EA/FGO composites achieved a 29.7% reduction in total heat release (THR) when containing only 0.1% FGO and a 38.6% reduction in peak-heat release rate (PHRR) when containing 3% FGO. The onset decomposition temperatures were delayed and the maximum decomposition values were reduced, according to thermogravimetric analysis which indicated enhanced thermal stabilities. The electrical conductivity was increased by 6 orders of magnitude (3% graphene) and the deleterious gas released during the thermo decomposition was reduced with the addition of all the graphite samples. This study represented a new approach to functionalize GO with flame retardant elements and active curable double bond to achieve better dispersion of GO into polymer matrix to obtain nanocomposites and paved a way for achieving graphene-based materials with high-performance of graphene in enhancement of flame retardancy of polymers for practical applications.

  3. Investigation of gamma radiation effect on chemical properties and surface morphology of some nonlinear optical (NLO) single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Ahlam, M.A., E-mail: omaymn771@yahoo.com [Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore 570 006, Karnataka (India); Ravishankar, M.N. [Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore 570 006, Karnataka (India); Vijayan, N. [Materials Characterization Division, National Physical Laboratory, New Delhi 110 012 (India); Govindaraj, G. [Department of Physics, Pondicherry University, Pondicherry 605 014 (India); Siddaramaiah [Department of Polymer and Technology, Sri Jayachamarajendra College of Engineering, Mysore 570 006 (India); Gnana Prakash, A.P., E-mail: gnanaprakash@physics.uni-mysore.ac.in [Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore 570 006, Karnataka (India)

    2012-05-01

    The effect of Co-60 gamma irradiation on L-alanine cadmium chloride (LACC), L-alanine doped potassium dihydrogen orthophosphate (KDP) and L-arginine doped KDP nonlinear optical (NLO) single crystals were studied in doses ranging from 100 krad to 6 Mrad. The crystals were grown by slow evaporation method at room temperature. The effects of gamma irradiation on the chemical, surface morphology, DC electrical conductivity, thermal and mechanical properties of the grown crystals have been studied. The functional groups of unirradiated and irradiated crystals have been identified and confirmed by Fourier transform infrared (FTIR) studies. Scanning electron microscopy (SEM) of irradiated crystals shows some morphological changes in the crystals. The dc conductivity of LACC and L-alanine doped KDP crystals were found to increase with increase in radiation dose whereas in case of L-arginine doped KDP crystals, the dc conductivity was found to decrease with increase in radiation dose. Differential scanning calorimetry (DSC) thermograms reveals that there is no significant change in the melting point of the crystals after irradiation and the crystals does not decompose as a result of irradiation. The mechanical behavior of both unirradiated and irradiated crystals is explained with the indentation effects using Vicker's microhardness tester. The Vicker's hardness number H{sub V} and Mayer's index 'n' has been estimated and confirms that LACC belong to the hard materials.

  4. Investigation of gamma radiation effect on chemical properties and surface morphology of some nonlinear optical (NLO) single crystals

    Science.gov (United States)

    Ahlam, M. A.; Ravishankar, M. N.; Vijayan, N.; Govindaraj, G.; Siddaramaiah; Gnana Prakash, A. P.

    2012-05-01

    The effect of Co-60 gamma irradiation on L-alanine cadmium chloride (LACC), L-alanine doped potassium dihydrogen orthophosphate (KDP) and L-arginine doped KDP nonlinear optical (NLO) single crystals were studied in doses ranging from 100 krad to 6 Mrad. The crystals were grown by slow evaporation method at room temperature. The effects of gamma irradiation on the chemical, surface morphology, DC electrical conductivity, thermal and mechanical properties of the grown crystals have been studied. The functional groups of unirradiated and irradiated crystals have been identified and confirmed by Fourier transform infrared (FTIR) studies. Scanning electron microscopy (SEM) of irradiated crystals shows some morphological changes in the crystals. The dc conductivity of LACC and L-alanine doped KDP crystals were found to increase with increase in radiation dose whereas in case of L-arginine doped KDP crystals, the dc conductivity was found to decrease with increase in radiation dose. Differential scanning calorimetry (DSC) thermograms reveals that there is no significant change in the melting point of the crystals after irradiation and the crystals does not decompose as a result of irradiation. The mechanical behavior of both unirradiated and irradiated crystals is explained with the indentation effects using Vicker's microhardness tester. The Vicker's hardness number HV and Mayer's index 'n' has been estimated and confirms that LACC belong to the hard materials.

  5. Transport and noise properties of Si nanowire channels with different lengths before and after gamma radiation treatment

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jing; Vitusevich, Svetlana; Pud, Sergii; Sydoruk, Viktor; Offenhäusser, Andreas [Peter Grünberg Institute, Forschungszentrum Jülich (Germany); Petrychuk, Mykhailo [Taras Shevchenko National University, Kiev (Ukraine); Danilchenko, Boris [Institute of Physics, NASU, Kiev (Ukraine)

    2013-12-04

    The transport properties of Si nanowire (NW) structures fabricated on the basis of silicon on insulator (SOI) wafers were studied using noise spectroscopy before and after treatment with small doses of gamma radiation. The total resistance obtained from the I-V characteristics of Si NW structures scaled perfectly with length. Normalized flicker noise demonstrated 1/L{sup 2} dependence, which is a characteristic of dominant noise contribution from near-contact regions. The behavior changed to 1/L dependence after a small dose (1×10{sup 4} Gy) of gamma radiation treatment. Comparison of the random telegraph signal (RTS) noise parameters in the samples with small lengths before and after the treatment revealed a decrease in RTS amplitude and a shift to a lower frequency range after gamma irradiation. These results confirmed that the main changes in the samples were related to strain relaxation near-contact regions. In addition, such treatment resulted in a considerable decrease in the scattering data of device parameters.

  6. A study of chemical composition and radiation attenuation properties in clinoptilolite-rich natural zeolite from Turkey

    Energy Technology Data Exchange (ETDEWEB)

    Kurudirek, Murat, E-mail: mkurudirek@gmail.co [Faculty of Science, Department of Physics, Ataturk University, 25240 Erzurum (Turkey); Ozdemir, Yueksel [Faculty of Science, Department of Physics, Ataturk University, 25240 Erzurum (Turkey); Tuerkmen, Ibrahim [Faculty of Engineering, Department of Civil Engineering, Inonu University, Malatya (Turkey); Levet, Aytac [Faculty of Science, Department of Physics, Ataturk University, 25240 Erzurum (Turkey)

    2010-11-15

    Clinoptilolite, a type of natural zeolite, has been commonly used as pozzolanic additive in concrete. This type of natural zeolite is generally used as a mineral admixture by substitution in Portland cement to produce high performance concretes. In the present study, the major, minor and trace element levels present in the clinoptilolite-rich natural zeolite (CRNZ) have been determined using a wavelength dispersive X-ray fluorescence spectrometer. Also, the clinoptilolite-rich natural zeolite has been compared with Portland cement with respect to the radiation attenuation properties. From the results it can be concluded that due to the natural radioactive content of clinoptilolite-rich natural zeolite (CRNZ) even if it is in trace level and also due to the poorer X-ray attenuation compared with Portland cement, special care should be taken to use this type of natural zeolite as blend materials in cements, etc.

  7. A study of chemical composition and radiation attenuation properties in clinoptilolite-rich natural zeolite from Turkey

    Science.gov (United States)

    Kurudirek, Murat; Özdemir, Yüksel; Türkmen, İbrahim; Levet, Aytaç

    2010-11-01

    Clinoptilolite, a type of natural zeolite, has been commonly used as pozzolanic additive in concrete. This type of natural zeolite is generally used as a mineral admixture by substitution in Portland cement to produce high performance concretes. In the present study, the major, minor and trace element levels present in the clinoptilolite-rich natural zeolite (CRNZ) have been determined using a wavelength dispersive X-ray fluorescence spectrometer. Also, the clinoptilolite-rich natural zeolite has been compared with Portland cement with respect to the radiation attenuation properties. From the results it can be concluded that due to the natural radioactive content of clinoptilolite-rich natural zeolite (CRNZ) even if it is in trace level and also due to the poorer X-ray attenuation compared with Portland cement, special care should be taken to use this type of natural zeolite as blend materials in cements, etc.

  8. Optical properties and radiation response of Ce{sup 3+}-doped GdScO{sub 3} crystals

    Energy Technology Data Exchange (ETDEWEB)

    Yamaji, Akihiro; Fujimoto, Yutaka; Futami, Yoshisuke; Yokota, Yuui; Kurosawa, Shunsuke [Institute of Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); Kochurikhin, Vladimir [General Physics Institute, 38 Vavilov Str., 119991 Moscow (Russian Federation); Yanagida, Takayuki [New Industry Creation Hatchery Center, Tohoku University, 6-6-10 Aramaki, Aoba-ku, Sendai 980-8579 (Japan); Yoshikawa, Akira [Institute of Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); New Industry Creation Hatchery Center, Tohoku University, 6-6-10 Aramaki, Aoba-ku, Sendai 980-8579 (Japan)

    2012-12-15

    10%-Ce doped GdScO{sub 3} perovskite type single crystal was grown by the Czochralski process. The Ce concentration in the crystal was measured. No impurity phases were observed by powder X-ray diffraction analysis. We evaluated the optical and radiation properties of the grown crystal. Ce:GdScO{sub 3} crystal showed photo- and radio-luminescence peaks due to Ce{sup 3+} of 5d-4f transition and colour centre. The photoluminescence decay time was sub-ns order. The relative light yield under 5.5 MeV alpha-ray excitation was calculated to be approximately 9% of BGO. (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  9. Essential properties of the Difference Method for the Search of the Anisotropy of the Primary Cosmic Radiation

    CERN Document Server

    Pavlyuchenko, V P; Nikolskaya, N M; Erlykin, A D

    2015-01-01

    The methodical properties of the original difference method for the search of the anisotropy at the knee region of the primary cosmic radiation energy spectrum are analyzed. The main feature of the suggested method is a study of the difference in the EAS characteristics in different directions but not their intensity. It is shown that the method is stable to the random experimental errors and allows to separate the anomalies related to the laboratory coordinate system from the anomalies in the celestial coordinates. The method uses multiple scattering of the charge particles in the Galaxy magnetic fields to study the whole celestial sphere including the regions outside of the line of sight of the installation.

  10. Assessing the radiative impacts of precipitating clouds on winter surface air temperatures and land surface properties in general circulation models using observations

    Science.gov (United States)

    Li, J.-L. F.; Lee, Wei-Liang; Wang, Yi-Hui; Richardson, Mark; Yu, Jia-Yuh; Suhas, E.; Fetzer, Eric; Lo, Min-Hui; Yue, Qing

    2016-10-01

    Using CloudSat-CALIPSO ice water, cloud fraction, and radiation; Clouds and the Earth's Radiant Energy System (CERES) radiation; and long-term station-measured surface air temperature (SAT), we identified a substantial underestimation of the total ice water path, total cloud fraction, land surface radiative flux, land surface temperature (LST), and SAT during Northern Hemisphere winter in Coupled Model Intercomparison Project Phase 5 (CMIP5) models. We perform sensitivity experiments with the National Center for Atmospheric Research (NCAR) Community Earth System Model version 1 (CESM1) in fully coupled modes to identify processes driving these biases. We found that biases in land surface properties are associated with the exclusion of downwelling longwave heating from precipitating ice during Northern Hemisphere winter. The land surface temperature biases introduced by the exclusion of precipitating ice radiative effects in CESM1 and CMIP5 both spatially correlate with winter biases over Eurasia and North America. The underestimated precipitating ice radiative effect leads to colder LST, associated surface energy-budget adjustments, and cooler SAT. This bias also shifts regional soil moisture state from liquid to frozen, increases snow cover, and depresses evapotranspiration (ET) and total leaf area index in Northern Hemisphere winter. The inclusion of the precipitating ice radiative effects largely reduces the model biases of surface radiative fluxes (more than 15 W m-2), SAT (up to 2-4 K), and snow cover and ET (25-30%), compared with those without snow-radiative effects.

  11. Properties of the Coherent Radiation Emitted from Photonic Crystal in the Millimeter Wave Region III(III. Accelerator, Synchrotron Radiation, and Instrumentation)

    OpenAIRE

    2006-01-01

    Coherent radiation emitted from a Photonic crystal of a cylindrical tube of Teflon with periodic grooves is observed in the millimeter wave region. The observed spectra show a sharp peak at frequency of 4.625cm^. The inter-bunch coherence of the radiation is confirmed with an interferometer.

  12. Effect of solar radiation on the optical properties and molecular composition of laboratory proxies of atmospheric brown carbon.

    Science.gov (United States)

    Lee, Hyun Ji Julie; Aiona, Paige Kuuipo; Laskin, Alexander; Laskin, Julia; Nizkorodov, Sergey A

    2014-09-02

    Sources, optical properties, and chemical composition of atmospheric brown carbon (BrC) aerosol are uncertain, making it challenging to estimate its contribution to radiative forcing. Furthermore, optical properties of BrC may change significantly during its atmospheric aging. We examined the effect of photolysis on the molecular composition, mass absorption coefficient, and fluorescence of secondary organic aerosol (SOA) prepared by high-NOx photooxidation of naphthalene (NAP SOA). Our experiments were designed to model photolysis processes of NAP SOA compounds dissolved in cloud or fog droplets. Aqueous solutions of NAP SOA were observed to photobleach (i.e., lose their ability to absorb visible radiation) with an effective half-life of ∼15 h (with sun in its zenith) for the loss of near-UV (300-400 nm) absorbance. The molecular composition of NAP SOA was significantly modified by photolysis, with the average SOA formula changing from C14.1H14.5O5.1N0.085 to C11.8H14.9O4.5N0.023 after 4 h of irradiation. However, the average O/C ratio did not change significantly, suggesting that it is not a good metric for assessing the extent of photolysis-driven aging in NAP SOA (and in BrC in general). In contrast to NAP SOA, the photobleaching of BrC material produced by the reaction of limonene + ozone SOA with ammonia vapor (aged LIM/O3 SOA) was much faster, but it did not result in a significant change in average molecular composition. The characteristic absorbance of the aged LIM/O3 SOA in the 450-600 nm range decayed with an effective half-life of <0.5 h. These results emphasize the highly variable and dynamic nature of different types of atmospheric BrC.

  13. Direct radiative forcing properties of atmospheric aerosols over semi-arid region, Anantapur in India

    Energy Technology Data Exchange (ETDEWEB)

    Kalluri, Raja Obul Reddy; Gugamsetty, Balakrishnaiah [Aerosol & Atmospheric Research Laboratory, Department of Physics, Sri Krishnadevaraya University, Anantapur 515 003, Andhra Pradesh (India); Kotalo, Rama Gopal, E-mail: krgverma@yahoo.com [Aerosol & Atmospheric Research Laboratory, Department of Physics, Sri Krishnadevaraya University, Anantapur 515 003, Andhra Pradesh (India); Nagireddy, Siva Kumar Reddy; Tandule, Chakradhar Rao; Thotli, Lokeswara Reddy [Aerosol & Atmospheric Research Laboratory, Department of Physics, Sri Krishnadevaraya University, Anantapur 515 003, Andhra Pradesh (India); Rajuru Ramakrishna, Reddy [Aerosol & Atmospheric Research Laboratory, Department of Physics, Sri Krishnadevaraya University, Anantapur 515 003, Andhra Pradesh (India); Srinivasa Ramanujan Institute of Technology, B.K. Samudram Mandal, Anantapur 515 701, Andhra Pradesh (India); Surendranair, Suresh Babu [Space Physics Laboratory, Vikram Sarabhai Space Centre, Trivandrum 695 022, Kerala (India)

    2016-10-01

    This paper describes the aerosols optical, physical characteristics and the aerosol radiative forcing pertaining to semi-arid region, Anantapur for the period January 2013-December 2014. Collocated measurements of Aerosol Optical Depth (AOD) and Black Carbon mass concentration (BC) are carried out by using MICROTOPS II and Aethalometer and estimated the aerosol radiative forcing over this location. The mean values of AOD at 500 nm are found to be 0.47 ± 0.09, 0.34 ± 0.08, 0.29 ± 0.06 and 0.30 ± 0.07 during summer, winter, monsoon and post-monsoon respectively. The Angstrom exponent (α{sub 380–1020}) value is observed maximum in March (1.25 ± 0.19) and which indicates the predominance of fine - mode aerosols and lowest in the month of July (0.33 ± 0.14) and may be due to the dominance of coarse-mode aerosols. The diurnal variation of BC is exhibited two height peaks during morning 07:00–08:00 (IST) and evening 19:00–21:00 (IST) hours and one minima noticed during afternoon (13:00–16:00). The highest monthly mean BC concentration is observed in the month of January (3.4 ± 1.2 μg m{sup −3}) and the lowest in July (1.1 ± 0.2 μg m{sup −3}). The estimated Aerosol Direct Radiative Forcing (ADRF) in the atmosphere is found to be + 36.8 ± 1.7 W m{sup −2}, + 26.9 ± 0.2 W m{sup −2}, + 18.0 ± 0.6 W m{sup −2} and + 18.5 ± 3.1 W m{sup −2} during summer, winter, monsoon and post-monsoon seasons, respectively. Large difference between TOA and BOA forcing is observed during summer which indicate the large absorption of radiant energy (36.80 W m{sup −2}) which contributes more increase in atmospheric heating by ~ 1 K/day. The BC contribution on an average is found to be 64% and is responsible for aerosol atmospheric heating. - Highlights: • The mean values of AOD{sub 500} are found to be high during summer whereas low in monsoon. • The highest values of BC are observed in January and the lowest in the month of July. • The annual mean

  14. Study of the thermoluminescent properties of silicate mineral irradiated with gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Barbosa, Renata F.; Watanabe, S.; Rocca, Rene R. [Universidade de Sao Paulo (IF/USP), SP (Brazil). Inst. de Fisica; Reichmann, Fernando [CBE-Embrarad Tecnologia em Esterilizacao, Cotia, SP (Brazil)

    2012-07-01

    Full text: The use of irradiation processes in medicine, industry has increased. This leads to investigation of different materials to be used as a radiation dosimeter. In this work, we investigate silicate mineral of pyroxene group, the jadeite of chemical formula NaAlSi{sub 2}O{sub 6}, as an aim. Three natural silicate minerals have been purchased as being jadeite, one lilac coloured from Turkey and the others two, green coloured from State of Minas Gerais, Brazil. The X-ray fluorescence analysis indicated, however that the lilac jadeite is actually much closer to alkali feldspar (indicated JF) and the others green coloured jadeites is predominantly of quartz structure (JQ), but one of these, presented chromium in its composition, indicated by JQC. So, we registered TL glow curves of 'jadeites' after irradiation from low to high doses. The Harshaw model 4500 TL reader has been used keeping 4 deg Cs{sup -1} heating rate for read out. A {sup 60}Co source was used for low doses gamma-irradiation at IPEN, Sao Paulo, Brazil. Moreover, for high doses of gamma irradiation, it was used a Nordion JS 9600 (rate dose of 30 kGy/h) at CBE/EMBRARAD, Cotia, Sao Paulo, Brazil. The powder was divided into portions and irradiated in the range of dose varying 0.1 to 70 kGy. The glow curves of JQ samples irradiated to 0.1 to 50 kGy gamma rays presented 110 (very short lived), 260 and 360 deg C TL peaks. 260 deg C peak is shifted by irradiation to lower temperature to about 210 deg C above 5 kGy, but the intensity increased steadily up to 10 kGy. It is important to note that much higher dose than 70 kGy can be clearly detected. This material is therefore, an excellent candidate to dosimetry in hundreds (or even more) of kGy region. On the other hand, the glow curves of JF sample under 0.1 to 50 kGy gamma-irradiation presented 150 deg C and 260 deg C peaks. The 150 deg C peak grows up to about 30 kGy and then saturate. Therefore, this crystal can be used in dosimetry below

  15. Performance of the ATLAS Transition Radiation Tracker in Run 1 of the LHC: tracker properties

    CERN Document Server

    Aaboud, Morad; Abbott, Brad; Abdallah, Jalal; Abdinov, Ovsat; Abeloos, Baptiste; Abidi, Syed Haider; AbouZeid, Ossama; Abraham, Nicola; Abramowicz, Halina; Abreu, Henso; Abreu, Ricardo; Abulaiti, Yiming; Acharya, Bobby Samir; Adachi, Shunsuke; Adamczyk, Leszek; Adams, David; Adelman, Jahred; Adersberger, Michael; Adye, Tim; Affolder, Tony; Agatonovic-Jovin, Tatjana; Agheorghiesei, Catalin; Aguilar-Saavedra, Juan Antonio; Ahlen, Steven; Ahmadov, Faig; Aielli, Giulio; Akatsuka, Shunichi; Akerstedt, Henrik; Åkesson, Torsten Paul Ake; Akimov, Andrei; Alberghi, Gian Luigi; Albert, Justin; Alconada Verzini, Maria Josefina; Aleksa, Martin; Aleksandrov, Igor; Alexa, Calin; Alexander, Gideon; Alexopoulos, Theodoros; Alhroob, Muhammad; Ali, Babar; Aliev, Malik; Alimonti, Gianluca; Alison, John; Alkire, Steven Patrick; Allbrooke, Benedict; Allen, Benjamin William; Allport, Phillip; Aloisio, Alberto; Alonso, Alejandro; Alonso, Francisco; Alpigiani, Cristiano; Alshehri, Azzah Aziz; Alstaty, Mahmoud; Alvarez Gonzalez, Barbara; Άlvarez Piqueras, Damián; Alviggi, Mariagrazia; Amadio, Brian Thomas; Amaral Coutinho, Yara; Amelung, Christoph; Amidei, Dante; Amor Dos Santos, Susana Patricia; Amorim, Antonio; Amoroso, Simone; Amundsen, Glenn; Anastopoulos, Christos; Ancu, Lucian Stefan; Andari, Nansi; Andeen, Timothy; Anders, Christoph Falk; Anders, John Kenneth; Anderson, Kelby; Andreazza, Attilio; Andrei, George Victor; Angelidakis, Stylianos; Angelozzi, Ivan; Angerami, Aaron; Anghinolfi, Francis; Anisenkov, Alexey; Anjos, Nuno; Annovi, Alberto; Antel, Claire; Antonelli, Mario; Antonov, Alexey; Antrim, Daniel Joseph; Anulli, Fabio; Aoki, Masato; Aperio Bella, Ludovica; Arabidze, Giorgi; Arai, Yasuo; Araque, Juan Pedro; Araujo Ferraz, Victor; Arce, Ayana; Ardell, Rose Elisabeth; Arduh, Francisco Anuar; Arguin, Jean-Francois; Argyropoulos, Spyridon; Arik, Metin; Armbruster, Aaron James; Armitage, Lewis James; Arnaez, Olivier; Arnold, Hannah; Arratia, Miguel; Arslan, Ozan; Artamonov, Andrei; Artoni, Giacomo; Artz, Sebastian; Asai, Shoji; Asbah, Nedaa; Ashkenazi, Adi; Asquith, Lily; Assamagan, Ketevi; Astalos, Robert; Atkinson, Markus; Atlay, Naim Bora; Augsten, Kamil; Avolio, Giuseppe; Axen, Bradley; Ayoub, Mohamad Kassem; Azuelos, Georges; Baas, Alessandra; Baca, Matthew John; Bachacou, Henri; Bachas, Konstantinos; Backes, Moritz; Backhaus, Malte; Bagiacchi, Paolo; Bagnaia, Paolo; Baines, John; Bajic, Milena; Baker, Oliver Keith; Baldin, Evgenii; Balek, Petr; Balestri, Thomas; Balli, Fabrice; Balunas, William Keaton; Banas, Elzbieta; Banerjee, Swagato; Bannoura, Arwa A E; Barak, Liron; Barberio, Elisabetta Luigia; Barberis, Dario; Barbero, Marlon; Barillari, Teresa; Barisits, Martin-Stefan; Barklow, Timothy; Barlow, Nick; Barnes, Sarah Louise; Barnett, Bruce; Barnett, Michael; Barnovska-Blenessy, Zuzana; Baroncelli, Antonio; Barone, Gaetano; Barr, Alan; Barranco Navarro, Laura; Barreiro, Fernando; Barreiro Guimarães da Costa, João; Bartoldus, Rainer; Barton, Adam Edward; Bartos, Pavol; Basalaev, Artem; Bassalat, Ahmed; Bates, Richard; Batista, Santiago Juan; Batley, Richard; Battaglia, Marco; Bauce, Matteo; Bauer, Florian; Bawa, Harinder Singh; Beacham, James; Beattie, Michael David; Beau, Tristan; Beauchemin, Pierre-Hugues; Bechtle, Philip; Beck, Hans~Peter; Becker, Kathrin; Becker, Maurice; Beckingham, Matthew; Becot, Cyril; Beddall, Andrew; Beddall, Ayda; Bednyakov, Vadim; Bedognetti, Matteo; Bee, Christopher; Beermann, Thomas; Begalli, Marcia; Begel, Michael; Behr, Janna Katharina; Bell, Andrew Stuart; Bella, Gideon; Bellagamba, Lorenzo; Bellerive, Alain; Bellomo, Massimiliano; Belotskiy, Konstantin; Beltramello, Olga; Belyaev, Nikita; Benary, Odette; Benchekroun, Driss; Bender, Michael; Bendtz, Katarina; Benekos, Nektarios; Benhammou, Yan; Benhar Noccioli, Eleonora; Benitez, Jose; Benjamin, Douglas; Benoit, Mathieu; Bensinger, James; Bentvelsen, Stan; Beresford, Lydia; Beretta, Matteo; Berge, David; Bergeaas Kuutmann, Elin; Berger, Nicolas; Beringer, Jürg; Berlendis, Simon; Bernard, Nathan Rogers; Bernardi, Gregorio; Bernius, Catrin; Bernlochner, Florian Urs; Berry, Tracey; Berta, Peter; Bertella, Claudia; Bertoli, Gabriele; Bertolucci, Federico; Bertram, Iain Alexander; Bertsche, Carolyn; Bertsche, David; Besjes, Geert-Jan; Bessidskaia Bylund, Olga; Bessner, Martin Florian; Besson, Nathalie; Betancourt, Christopher; Bethani, Agni; Bethke, Siegfried; Bevan, Adrian John; Bianchi, Riccardo-Maria; Bianco, Michele; Biebel, Otmar; Biedermann, Dustin; Bielski, Rafal; Biesuz, Nicolo Vladi; Biglietti, Michela

    2017-01-01

    The tracking performance parameters of the ATLAS Transition Radiation Tracker (TRT) as part of the ATLAS inner detector are described in this paper for different data-taking conditions in proton--proton, proton--lead and lead--lead collisions at the Large Hadron Collider (LHC). The performance is studied using data collected for different data-taking conditions in proton--proton, proton--lead and lead--lead collisions at the Large Hadron Collider (LHC). The performance is studied using data collected during the first period of LHC operation (Run 1) and is compared with Monte Carlo simulations. The performance of the TRT, operating with two different gas mixtures (xenon-based and argon-based) and its dependence on the TRT occupancy is presented. These studies show that the tracking performance of the TRT is similar for the two gas mixtures and that a significant contribution to the particle momentum resolution is made by the TRT up to high particle densities.

  16. Scintillation properties of semiconducting {sup 6}LiInSe{sub 2} crystals to ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Wiggins, Brenden [Y-12 National Security Complex, Oak Ridge, TN (United States); Vanderbilt University, Nashville, TN (United States); Groza, Michael; Tupitsyn, Eugene [Fisk University, Nashville, TN (United States); Lukosi, Eric [University of Tennessee, Knoxville, TN (United States); Stassun, Keivan; Burger, Arnold [Vanderbilt University, Nashville, TN (United States); Fisk University, Nashville, TN (United States); Stowe, Ashley [Y-12 National Security Complex, Oak Ridge, TN (United States); Vanderbilt University, Nashville, TN (United States); University of Tennessee, Knoxville, TN (United States)

    2015-11-21

    {sup 6}LiInSe{sub 2} has gained attention recently as a semiconducting thermal neutron detector. As presented herein, the chalcogenide compound semiconductor also detects incident neutrons via scintillation, making {sup 6}LiInSe{sub 2} the only lithium containing semiconductor to respond to neutrons via both detection mechanisms. Both yellow and red crystals, which appear in the literature, were investigated. Only the yellow crystal responded favorably to ionizing radiation, similar to the semiconducting operation utilizing electrodes. The obtained light yield for yellow crystals is 4400 photons/MeV, referenced to Bi{sub 4}Ge{sub 3}O{sub 12} (BGO).The estimated thermal neutron light yield was 21,000 photons/thermal neutron. The two measured decay time components were found to be 31±1 ns (49%) and 143±9 ns (51%).This crystal provides efficient, robust detection of neutrons via scintillation with respectable light yield and rapid response, enabling its use for a broad array of neutron detection applications.

  17. Dynamical and Radiative Properties of X-Ray Pulsar Accretion Columns: Phase-averaged Spectra

    Science.gov (United States)

    West, Brent F.; Wolfram, Kenneth D.; Becker, Peter A.

    2017-02-01

    The availability of the unprecedented spectral resolution provided by modern X-ray observatories is opening up new areas for study involving the coupled formation of the continuum emission and the cyclotron absorption features in accretion-powered X-ray pulsar spectra. Previous research focusing on the dynamics and the associated formation of the observed spectra has largely been confined to the single-fluid model, in which the super-Eddington luminosity inside the column decelerates the flow to rest at the stellar surface, while the dynamical effect of gas pressure is ignored. In a companion paper, we have presented a detailed analysis of the hydrodynamic and thermodynamic structure of the accretion column obtained using a new self-consistent model that includes the effects of both gas and radiation pressures. In this paper, we explore the formation of the associated X-ray spectra using a rigorous photon transport equation that is consistent with the hydrodynamic and thermodynamic structure of the column. We use the new model to obtain phase-averaged spectra and partially occulted spectra for Her X-1, Cen X-3, and LMC X-4. We also use the new model to constrain the emission geometry, and compare the resulting parameters with those obtained using previously published models. Our model sheds new light on the structure of the column, the relationship between the ionized gas and the photons, the competition between diffusive and advective transport, and the magnitude of the energy-averaged cyclotron scattering cross-section.

  18. Structure and properties of the radiation-induced intermediates produced from HCN in noble gas matrices

    Science.gov (United States)

    Kameneva, Svetlana V.; Tyurin, Daniil A.; Feldman, Vladimir I.

    2016-07-01

    In this work we report the results of systematic studies on the radiation-induced transformations in HCN/Ng systems (Ng=Ne, Ar, Kr or Xe) at 7 K using a combination of FTIR and EPR spectroscopy. It was shown that HCN underwent efficient decomposition producing H atoms, CN radicals and HNC isomer. The thermally induced reactions of H atoms in different matrices result in the formation of two isomeric radicals, H2CN and trans-HCNH, the former being predominated. The temperature dependent dynamics of CN and H2CN radicals in a krypton matrix was observed by EPR spectroscopy in solid krypton. The vibrational frequencies, IR intensities and magnetic resonance parameters of H2CN and trans-HCNH radicals calculated at the CCSD(T) level are in reasonable agreement with the experimental results. It was found that HCNH radical could be effectively bleached with visible light. The comparison of experimental and computational data made it possible to assign a new vibrational band at 918 cm-1 in an Ar matrix (and the corresponding bands in Kr and Xe) to trans-HCNH radical. In addition, HKrCN was found in the case of krypton, whereas HXeCN and HXeNC were produced in solid xenon. The reaction mechanisms and contribution of different channels are discussed.

  19. Non-relativistic radiation mediated shock breakouts: III. Spectral properties of SN shock breakout

    CERN Document Server

    Sapir, Nir; Waxman, Eli

    2013-01-01

    The spectrum of radiation emitted following shock breakout from a star's surface with a power-law density profile $\\rho \\propto x^n$ is investigated. Assuming planar geometry, local Compton equilibrium and bremsstrahlung emission as the dominant photon production mechanism, numerical solutions are obtained for the photon number density and temperature profiles as a function of time, for hydrogen-helium envelopes. The temperature solutions are determined by the breakout shock velocity $v_0$ and the pre-shock breakout density $\\rho_0$, and depend weakly on the value of n. Fitting formulas for the peak surface temperature at breakout as a function of $v_0$ and $\\rho_0$ are provided, with $T_{peak}\\approx 9.44\\exp{[12.63(v_0/c)^{1/2}]}$ eV, and the time dependence of the surface temperature is tabulated. The time integrated emitted spectrum is a robust prediction of the model, determined by $\\mathcal{T}_{\\rm peak}$ and $v_0$ alone and insensitive to details of light travel time or slight deviations from spherical...

  20. Radiation Chemistry

    Science.gov (United States)

    Wojnárovits, L.

    Ionizing radiation causes chemical changes in the molecules of the interacting medium. The initial molecules change to new molecules, resulting in changes of the physical, chemical, and eventually biological properties of the material. For instance, water decomposes to its elements H2 and O2. In polymers, degradation and crosslinking take place. In biopolymers, e.g., DNS strand breaks and other alterations occur. Such changes are to be avoided in some cases (radiation protection), however, in other cases they are used for technological purposes (radiation processing). This chapter introduces radiation chemistry by discussing the sources of ionizing radiation (radionuclide sources, machine sources), absorption of radiation energy, techniques used in radiation chemistry research, and methods of absorbed energy (absorbed dose) measurements. Radiation chemistry of different classes of inorganic (water and aqueous solutions, inorganic solids, ionic liquids (ILs)) and organic substances (hydrocarbons, halogenated compounds, polymers, and biomolecules) is discussed in concise form together with theoretical and experimental backgrounds. An essential part of the chapter is the introduction of radiation processing technologies in the fields of polymer chemistry, food processing, and sterilization. The application of radiation chemistry to nuclear technology and to protection of environment (flue gas treatment, wastewater treatment) is also discussed.

  1. Probabilistic assessment of the influence of lake properties in long-term radiation doses to humans.

    Science.gov (United States)

    Pohjola, Jari; Turunen, Jari; Lipping, Tarmo; Ikonen, Ari T K

    2016-11-01

    The assessment processes concerning the safety of nuclear waste repositories include the modelling of radionuclide transport in biosphere and the evaluation of the doses to the most affected humans. In this paper, a scenario, in which a contaminated lake is the water source for drinking water, irrigation water and watering of livestock, is presented. The objective of the paper is to probabilistically study the influence of lake properties as parameters in the assessment scenario. The properties of the lake are a result of previously conducted probabilistic studies, where the land uplift of the terrain surrounding the repositories and the formation of water bodies were studied in a 10,000-year time span using Monte Carlo simulation. The lake is formed at 3000 years from present day and the changing properties of the lake have been used in the study. The studied radionuclides (36)Cl, (135)Cs, (129)I, (237)Np, (90)Sr, (99)Tc and (238)U enter the lake with a rate of 1 Bq/year. The transport process from the lake water to humans is described and the doses (dose conversion factors) to adult humans are evaluated based on a study on average food consumption. Sensitivity analysis is used for identifying the parameters having the most influence on the outcome of the dose. Based on the results from the sensitivity analysis, the volumetric outflow rate of the lake and the volume of the lake were taken into closer consideration. The results show the influence of probabilistically derived geomorphic lake input parameters on the dose. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. The structure and properties of different types of starch exposed to UV radiation: a comparative study.

    Science.gov (United States)

    Bajer, Dagmara; Kaczmarek, Halina; Bajer, Krzysztof

    2013-10-15

    The effect of UV-irradiation on four different types of native starch (corn, waxy corn, wheat and potato) have been investigated. Although the changes in the chemical structure of starch specimens were small, indicating good photostability, the samples lost adsorbed water and their crystallinity degree decreased after irradiation. Moreover, a drop in average molecular weight occurred in samples (with the exception of potato starch) as a result of main chain scission. The variations in the properties of investigated specimens of various origin were related to the differences in their structure and macromolecular arrangement. The lowest photostability among the four starches was exhibited by potato starch.