Experimental study on the thermal performance of a new type of thermal energy storage based on flat micro-heat pipe array

International Nuclear Information System (INIS)

Li, Feng-fei; Diao, Yan-hua; Zhao, Yao-hua; Zhu, Ting-ting; Liu, Jing

2016-01-01

Highlights: • A novel thermal energy storage based on flat micro-heat pipe array is proposed. • The thermal storage shows excellent thermal performance in the working process. • The novel thermal storage has the advantage of low flow resistance. - Abstract: The thermal performance of an air-based phase change storage unit is analyzed and discussed in this study. The thermal energy storage uses flat micro-heat pipe array (FMHPA) as the core heat transfer component and lauric acid as phase change material (PCM). An experimental system is devised to test the heat storage–release property of the storage unit under different inlet temperatures and flow rates of the heat transfer medium. The performance of the storage unit and the melting/solidification curves of the phase change material are obtained based on extensive experimental data. Experimental results indicate that the flat micro-heat pipe array exhibits excellent temperature uniformity in the heat storage–release process, and the performance of the storage unit is efficient and steady.

Fabrication of high thermal conductivity arrays of carbon nanotubes and their composites

Science.gov (United States)

Geohegan, David B [Knoxville, TN; Ivanov, Ilya N [Knoxville, TN; Puretzky, Alexander A [Knoxville, TN

2010-07-27

Methods and apparatus are described for fabrication of high thermal conductivity arrays of carbon nanotubes and their composites. A composition includes a vertically aligned nanotube array including a plurality of nanotubes characterized by a property across substantially all of the vertically aligned nanotube array. A method includes depositing a vertically aligned nanotube array that includes a plurality of nanotubes; and controlling a deposition rate of the vertically aligned nanotubes array as a function of an in situ monitored property of the plurality of nanotubes.

Fabrication of three-dimensional ordered nanodot array structures by a thermal dewetting method

International Nuclear Information System (INIS)

Li Zhenxing; Yoshino, Masahiko; Yamanaka, Akinori

2012-01-01

A new fabrication method for three-dimensional nanodot arrays with low cost and high throughput is developed in this paper. In this process, firstly a 2D nanodot array is fabricated by combination of top-down and bottom-up approaches. A nanoplastic forming technique is utilized as the top-down approach to fabricate a groove grid pattern on an Au layer deposited on a substrate, and self-organization by thermal dewetting is employed as the bottom-up approach. On the first-layer nanodot array, SiO 2 is deposited as a spacer layer. Au is then deposited on the spacer layer and thermal dewetting is conducted to fabricate a second-layer nanodot array. The effective parameters influencing dot formation on the second layer, including Au layer thickness and SiO 2 layer thickness, are studied. It is demonstrated that a 3D nanodot array of good vertical alignment is obtained by repeating the SiO 2 deposition, Au deposition and thermal dewetting. The mechanism of the dot agglomeration process is studied based on geometrical models. The effects of the spacer layer thickness and Au layer thickness on the morphology and alignment of the second-layer dots are discussed. (paper)

Thermal design of spacecraft solar arrays using a polyimide foam

International Nuclear Information System (INIS)

Bianco, N; Iasiello, M; Naso, V

2015-01-01

The design of the Thermal Control System (TCS) of spacecraft solar arrays plays a fundamental role. Indeed, the spacecraft components must operate within a certain range of temperature. If this doesn't occur, their performance is reduced and they may even break. Solar arrays, which are employed to recharge batteries, are directly exposed to the solar heat flux, and they need to be insulated from the earth's surface irradiation. Insulation is currently provided either with a white paint coating or with a Multi Layer Insulation (MLI) system [1]. A configuration based on an open-cell polyimide foam has also been recently proposed [2]. Using polyimide foams in TCSs looks very attractive in terms of costs, weight and assembling. An innovative thermal analysis of the above cited TCS configurations is carried out in this paper, by solving the porous media energy equation, under the assumption of Local Thermal Equilibrium (LTE) between the two phases. Radiation effects through the solar array are also considered by using the Rosseland approximation. Under a stationary daylight condition, temperature profiles are obtained by means of the finite-element based code COMSOL Multiphysics ® . Finally, since the weight plays an important role in aerospace applications, weights of the three TCS configurations are compared. (paper)

Thermal design of spacecraft solar arrays using a polyimide foam

Science.gov (United States)

Bianco, N.; Iasiello, M.; Naso, V.

2015-11-01

The design of the Thermal Control System (TCS) of spacecraft solar arrays plays a fundamental role. Indeed, the spacecraft components must operate within a certain range of temperature. If this doesn't occur, their performance is reduced and they may even break. Solar arrays, which are employed to recharge batteries, are directly exposed to the solar heat flux, and they need to be insulated from the earth's surface irradiation. Insulation is currently provided either with a white paint coating or with a Multi Layer Insulation (MLI) system [1]. A configuration based on an open-cell polyimide foam has also been recently proposed [2]. Using polyimide foams in TCSs looks very attractive in terms of costs, weight and assembling. An innovative thermal analysis of the above cited TCS configurations is carried out in this paper, by solving the porous media energy equation, under the assumption of Local Thermal Equilibrium (LTE) between the two phases. Radiation effects through the solar array are also considered by using the Rosseland approximation. Under a stationary daylight condition, temperature profiles are obtained by means of the finite-element based code COMSOL Multiphysics®. Finally, since the weight plays an important role in aerospace applications, weights of the three TCS configurations are compared.

A multi-frequency sparse hemispherical ultrasound phased array for microbubble-mediated transcranial therapy and simultaneous cavitation mapping.

Science.gov (United States)

Deng, Lulu; O'Reilly, Meaghan A; Jones, Ryan M; An, Ran; Hynynen, Kullervo

2016-12-21

Focused ultrasound (FUS) phased arrays show promise for non-invasive brain therapy. However, the majority of them are limited to a single transmit/receive frequency and therefore lack the versatility to expose and monitor the treatment volume. Multi-frequency arrays could offer variable transmit focal sizes under a fixed aperture, and detect different spectral content on receive for imaging purposes. Here, a three-frequency (306, 612, and 1224 kHz) sparse hemispherical ultrasound phased array (31.8 cm aperture; 128 transducer modules) was constructed and evaluated for microbubble-mediated transcranial therapy and simultaneous cavitation mapping. The array is able to perform effective electronic beam steering over a volume spanning (-40, 40) and (-30, 50) mm in the lateral and axial directions, respectively. The focal size at the geometric center is approximately 0.9 (2.1) mm, 1.7 (3.9) mm, and 3.1 (6.5) mm in lateral (axial) pressure full width at half maximum (FWHM) at 1224, 612, and 306 kHz, respectively. The array was also found capable of dual-frequency excitation and simultaneous multi-foci sonication, which enables the future exploration of more complex exposure strategies. Passive acoustic mapping of dilute microbubble clouds demonstrated that the point spread function of the receive array has a lateral (axial) intensity FWHM between 0.8-3.5 mm (1.7-11.7 mm) over a volume spanning (-25, 25) mm in both the lateral and axial directions, depending on the transmit/receive frequency combination and the imaging location. The device enabled both half and second harmonic imaging through the intact skull, which may be useful for improving the contrast-to-tissue ratio or imaging resolution, respectively. Preliminary in vivo experiments demonstrated the system's ability to induce blood-brain barrier opening and simultaneously spatially map microbubble cavitation activity in a rat model. This work presents a tool to investigate optimal strategies for non-thermal

A cryogenic thermal source for detector array characterization

Science.gov (United States)

Chuss, David T.; Rostem, Karwan; Wollack, Edward J.; Berman, Leah; Colazo, Felipe; DeGeorge, Martin; Helson, Kyle; Sagliocca, Marco

2017-10-01

We describe the design, fabrication, and validation of a cryogenically compatible quasioptical thermal source for characterization of detector arrays. The source is constructed using a graphite-loaded epoxy mixture that is molded into a tiled pyramidal structure. The mold is fabricated using a hardened steel template produced via a wire electron discharge machining process. The absorptive mixture is bonded to a copper backplate enabling thermalization of the entire structure and measurement of the source temperature. Measurements indicate that the reflectance of the source is <0.001 across a spectral band extending from 75 to 330 GHz.

Equivalent thermal history reconstruction from a partially crystallized glass-ceramic sensor array

Science.gov (United States)

Heeg, Bauke

2015-11-01

The basic concept of a thermal history sensor is that it records the accumulated exposure to some unknown, typically varying temperature profile for a certain amount of time. Such a sensor is considered to be capable of measuring the duration of several (N) temperature intervals. For this purpose, the sensor deploys multiple (M) sensing elements, each with different temperature sensitivity. At the end of some thermal exposure for a known period of time, the sensor array is read-out and an estimate is made of the set of N durations of the different temperature ranges. A potential implementation of such a sensor was pioneered by Fair et al. [Sens. Actuators, A 141, 245 (2008)], based on glass-ceramic materials with different temperature-dependent crystallization dynamics. In their work, it was demonstrated that an array of sensor elements can be made sensitive to slight differences in temperature history. Further, a forward crystallization model was used to simulate the variations in sensor array response to differences in the temperature history. The current paper focusses on the inverse aspect of temperature history reconstruction from a hypothetical sensor array output. The goal of such a reconstruction is to find an equivalent thermal history that is the closest representation of the true thermal history, i.e., the durations of a set of temperature intervals that result in a set of fractional crystallization values which is closest to the one resulting from the true thermal history. One particular useful simplification in both the sensor model as well as in its practical implementation is the omission of nucleation effects. In that case, least squares models can be used to approximate the sensor response and make reconstruction estimates. Even with this simplification, sensor noise can have a destabilizing effect on possible reconstruction solutions, which is evaluated using simulations. Both regularization and non-negativity constrained least squares

Film-Evaporation MEMS Tunable Array for Picosat Propulsion and Thermal Control

Science.gov (United States)

Alexeenko, Alina; Cardiff, Eric; Martinez, Andres; Petro, Andrew

2015-01-01

The Film-Evaporation MEMS Tunable Array (FEMTA) concept for propulsion and thermal control of picosats exploits microscale surface tension effect in conjunction with temperature- dependent vapor pressure to realize compact, tunable and low-power thermal valving system. The FEMTA is intended to be a self-contained propulsion unit requiring only a low-voltage DC power source to operate. The microfabricated thermal valving and very-high-integration level enables fast high-capacity cooling and high-resolution, low-power micropropulsion for picosats that is superior to existing smallsat micropropulsion and thermal management alternatives.

Thermal conductivity of vertically aligned carbon nanotube arrays: Growth conditions and tube inhomogeneity

Energy Technology Data Exchange (ETDEWEB)

Bauer, Matthew L.; Pham, Quang N.; Saltonstall, Christopher B.; Norris, Pamela M. [Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, Virginia 22904-4746 (United States)

2014-10-13

The thermal conductivity of vertically aligned carbon nanotube arrays (VACNTAs) grown on silicon dioxide substrates via chemical vapor deposition is measured using a 3ω technique. For each sample, the VACNTA layer and substrate are pressed to a heating line at varying pressures to extract the sample's thermophysical properties. The nanotubes' structure is observed via transmission electron microscopy and Raman spectroscopy. The presence of hydrogen and water vapor in the fabrication process is tuned to observe the effect on measured thermal properties. The presence of iron catalyst particles within the individual nanotubes prevents the array from achieving the overall thermal conductivity anticipated based on reported measurements of individual nanotubes and the packing density.

Turbulence, chaos and thermal noise in globally coupled Josephson junction arrays

International Nuclear Information System (INIS)

Dominguez, D.

1995-03-01

We discuss the effects of thermal noise in underdamped Josephson junction series arrays that are globally coupled through a resistive load and driven by an rf current. We study the breakdown of the law of large numbers in the turbulent phase of the Josephson arrays. This corresponds to a saturation of the broad band noise S 0 for a large number N of junctions. We find that this phenomenon is stable against thermal fluctuations below a critical temperature T cl . The behaviour of S 0 vs. T, for large N, shows three different regimes. For 0 cl , S 0 decreases when increasing T, and there is turbulence and the breakdown of the law of large numbers. For T cl c2 , S 0 is constant and the dynamics is dominated by the chaos of the individual junctions. Finally for T > T c2 , S 0 in mainly due to thermal fluctuations, since it increases linearly with T. (author). 23 refs, 6 figs

Image-guided ultrasound phased arrays are a disruptive technology for non-invasive therapy.

Science.gov (United States)

Hynynen, Kullervo; Jones, Ryan M

2016-09-07

Focused ultrasound offers a non-invasive way of depositing acoustic energy deep into the body, which can be harnessed for a broad spectrum of therapeutic purposes, including tissue ablation, the targeting of therapeutic agents, and stem cell delivery. Phased array transducers enable electronic control over the beam geometry and direction, and can be tailored to provide optimal energy deposition patterns for a given therapeutic application. Their use in combination with modern medical imaging for therapy guidance allows precise targeting, online monitoring, and post-treatment evaluation of the ultrasound-mediated bioeffects. In the past there have been some technical obstacles hindering the construction of large aperture, high-power, densely-populated phased arrays and, as a result, they have not been fully exploited for therapy delivery to date. However, recent research has made the construction of such arrays feasible, and it is expected that their continued development will both greatly improve the safety and efficacy of existing ultrasound therapies as well as enable treatments that are not currently possible with existing technology. This review will summarize the basic principles, current statures, and future potential of image-guided ultrasound phased arrays for therapy.

Thermal analysis for folded solar array of spacecraft in orbit

International Nuclear Information System (INIS)

Yang, W.H.; Cheng, H.E.; Cai, A.

2004-01-01

The combined radiation-conduction heat transfer in folded solar array was considered as a three-dimensional anisotropic conduction without inner heat source. The three-dimensional equivalent conductivity in cell plate were obtained. The especially discrete equation coefficients of the nodes on the surfaces of adjacent cell plates were deduced by utilizing the simplified radiation network among the two adjacent cell plate surfaces and the deep cold space. All the thermal influence factors on the temperature response of the folded solar array were considered carefully. SIP method was used to solve the discrete equation. By comparing the calculation results under three cases, the temperature response and the maximum average difference of the folded solar array was obtained during the period of throw-radome of the launch vehicle and spread of the folded solar array. The obtained result is a valuable reference for the selection of the launch time of the spacecraft

A thermal plasmonic sensor platform: resistive heating of nanohole arrays.

Science.gov (United States)

Virk, Mudassar; Xiong, Kunli; Svedendahl, Mikael; Käll, Mikael; Dahlin, Andreas B

2014-06-11

We have created a simple and efficient thermal plasmonic sensor platform by letting a DC current heat plasmonic nanohole arrays. The sensor can be used to determine thermodynamic parameters in addition to monitoring molecular reactions in real-time. As an application example, we use the thermal sensor to determine the kinetics and activation energy for desorption of thiol monolayers on gold. Further, the temperature of the metal can be measured optically by the spectral shift of the bonding surface plasmon mode (0.015 nm/K). We show that this resonance shift is caused by thermal lattice expansion, which reduces the plasma frequency of the metal. The sensor is also used to determine the thin film thermal expansion coefficient through a theoretical model for the expected resonance shift.

Thin-film sparse boundary array design for passive acoustic mapping during ultrasound therapy.

Science.gov (United States)

Coviello, Christian M; Kozick, Richard J; Hurrell, Andrew; Smith, Penny Probert; Coussios, Constantin-C

2012-10-01

A new 2-D hydrophone array for ultrasound therapy monitoring is presented, along with a novel algorithm for passive acoustic mapping using a sparse weighted aperture. The array is constructed using existing polyvinylidene fluoride (PVDF) ultrasound sensor technology, and is utilized for its broadband characteristics and its high receive sensitivity. For most 2-D arrays, high-resolution imagery is desired, which requires a large aperture at the cost of a large number of elements. The proposed array's geometry is sparse, with elements only on the boundary of the rectangular aperture. The missing information from the interior is filled in using linear imaging techniques. After receiving acoustic emissions during ultrasound therapy, this algorithm applies an apodization to the sparse aperture to limit side lobes and then reconstructs acoustic activity with high spatiotemporal resolution. Experiments show verification of the theoretical point spread function, and cavitation maps in agar phantoms correspond closely to predicted areas, showing the validity of the array and methodology.

Treatment time reduction for large thermal lesions by using a multiple 1D ultrasound phased array system

International Nuclear Information System (INIS)

Liu, H.-L.; Chen, Y.-Y.; Yen, J.-Y.; Lin, W.-L.

2003-01-01

To generate large thermal lesions in ultrasound thermal therapy, cooling intermissions are usually introduced during the treatment to prevent near-field heating, which leads to a long treatment time. A possible strategy to shorten the total treatment time is to eliminate the cooling intermissions. In this study, the two methods, power optimization and acoustic window enlargement, for reducing power accumulation in the near field are combined to investigate the feasibility of continuously heating a large target region (maximally 3.2 x 3.2 x 3.2 cm 3 ). A multiple 1D ultrasound phased array system generates the foci to scan the target region. Simulations show that the target region can be successfully heated without cooling and no near-field heating occurs. Moreover, due to the fact that there is no cooling time during the heating sessions, the total treatment time is significantly reduced to only several minutes, compared to the existing several hours

Optimization of single channel glazed photovoltaic thermal (PVT) array using Evolutionary Algorithm (EA) and carbon credit earned by the optimized array

International Nuclear Information System (INIS)

Singh, Sonveer; Agrawal, Sanjay; Gadh, Rajit

2015-01-01

Highlights: • Optimization of SCGPVT array using Evolutionary Algorithm. • The overall exergy gain is maximized with an Evolutionary Algorithm. • Annual Performance has been evaluated for New Delhi (India). • There are improvement in results than the model given in literature. • Carbon credit analysis has been done. - Abstract: In this paper, work is carried out in three steps. In the first step, optimization of single channel glazed photovoltaic thermal (SCGPVT) array has been done with an Evolutionary Algorithm (EA) keeping the overall exergy gain is an objective function of the SCGPVT array. For maximization of overall exergy gain, total seven design variables have been optimized such as length of the channel (L), mass flow rate of flowing fluid (m_F), velocity of flowing fluid (V_F), convective heat transfer coefficient through the tedlar (U_T), overall heat transfer coefficient between solar cell to ambient through glass cover (U_S_C_A_G), overall back loss heat transfer coefficient from flowing fluid to ambient (U_F_A) and convective heat transfer coefficient of tedlar (h_T). It has been observed that the instant overall exergy gain obtained from optimized system is 1.42 kW h, which is 87.86% more than the overall exergy gain of a un-optimized system given in literature. In the second step, overall exergy gain and overall thermal gain of SCGPVT array has been evaluated annually and there are 69.52% and 88.05% improvement in annual overall exergy gain and annual overall thermal gain respectively than the un-optimized system for the same input irradiance and ambient temperature. In the third step, carbon credit earned by the optimized SCGPVT array has also been evaluated as per norms of Kyoto Protocol Bangalore climatic conditions.

Characterization of Thermal Cross-talk in a γ-ray Microcalorimeter Array

International Nuclear Information System (INIS)

Jethava, N.; Ullom, J. N.; Bennett, D. A.; Irwin, K. D.; Horansky, R. D.; Beall, J. A.; Hilton, G. C.; Vale, L. R.; Hoover, A.; Bacrania, M. K.; Rabin, M. W.

2009-01-01

We present experimental data describing cross-talk within an array of gamma-ray microcalorimeters during gamma-ray irradiation. The microcalorimeters consist of Mo/Cu transition-edge sensors (TESs) with attached Sn absorbers. We observe both thermal and electrical cross-talk with peak cross-talk amplitudes as large as 0.4%. We have developed an analytical model for thermal cross-talk and make a preliminary comparison to data. Cross-talk must be understood and minimized for high resolution spectroscopy at high input count rates.

Thermal microphotonic sensor and sensor array

Science.gov (United States)

Watts, Michael R [Albuquerque, NM; Shaw, Michael J [Tijeras, NM; Nielson, Gregory N [Albuquerque, NM; Lentine, Anthony L [Albuquerque, NM

2010-02-23

A thermal microphotonic sensor is disclosed for detecting infrared radiation using heat generated by the infrared radiation to shift the resonant frequency of an optical resonator (e.g. a ring resonator) to which the heat is coupled. The shift in the resonant frequency can be determined from light in an optical waveguide which is evanescently coupled to the optical resonator. An infrared absorber can be provided on the optical waveguide either as a coating or as a plate to aid in absorption of the infrared radiation. In some cases, a vertical resonant cavity can be formed about the infrared absorber to further increase the absorption of the infrared radiation. The sensor can be formed as a single device, or as an array for imaging the infrared radiation.

MR-guided noninvasive thermal coagulation of in-vivo liver tissue using ultrasonic phased array

Science.gov (United States)

Daum, Douglas R.; Smith, Nadine; McDannold, Nathan; Hynynen, Kullervo H.

1999-05-01

Magnetic resonance (MR) imaging was used to guide and monitor the thermal tissue coagulation of in vivo porcine tissue using a 256 element ultrasonic phased array. The array could coagulate tissue volumes greater than 2 cm3 in liver and 0.5 cm3 in kidney using a single 20 second sonication. This sonication used multiple focus fields which were temporally cycled to heat large tissue volumes simultaneously. Estimates of the coagulated tissue using a thermal dose threshold compare well with T2-weighted images of post sonication lesions. The overlapping large focal volumes could aid in the treatment of large tumor volumes which require multiple overlapping sonications. The ability of MR to detect the presence and undesirable thermal increases at acoustic obstacle such as cartilaginous and bony ribs is demonstrated. This could have a significant impact on the ability to monitor thermal treatments of the liver and other organs which are acoustically blocked.

Realization of thermally durable close-packed 2D gold nanoparticle arrays using self-assembly and plasma etching

International Nuclear Information System (INIS)

Sivaraman, Sankar K; Santhanam, Venugopal

2012-01-01

Realization of thermally and chemically durable, ordered gold nanostructures using bottom-up self-assembly techniques are essential for applications in a wide range of areas including catalysis, energy generation, and sensing. Herein, we describe a modular process for realizing uniform arrays of gold nanoparticles, with interparticle spacings of 2 nm and above, by using RF plasma etching to remove ligands from self-assembled arrays of ligand-coated gold nanoparticles. Both nanoscale imaging and macroscale spectroscopic characterization techniques were used to determine the optimal conditions for plasma etching, namely RF power, operating pressure, duration of treatment, and type of gas. We then studied the effect of nanoparticle size, interparticle spacing, and type of substrate on the thermal durability of plasma-treated and untreated nanoparticle arrays. Plasma-treated arrays showed enhanced chemical and thermal durability, on account of the removal of ligands. To illustrate the application potential of the developed process, robust SERS (surface-enhanced Raman scattering) substrates were formed using plasma-treated arrays of silver-coated gold nanoparticles that had a silicon wafer or photopaper as the underlying support. The measured value of the average SERS enhancement factor (2 × 10 5 ) was quantitatively reproducible on both silicon and paper substrates. The silicon substrates gave quantitatively reproducible results even after thermal annealing. The paper-based SERS substrate was also used to swab and detect probe molecules deposited on a solid surface. (paper)

Thermal modelling using discrete vasculature for thermal therapy: a review

Science.gov (United States)

Kok, H.P.; Gellermann, J.; van den Berg, C.A.T.; Stauffer, P.R.; Hand, J.W.; Crezee, J.

2013-01-01

Reliable temperature information during clinical hyperthermia and thermal ablation is essential for adequate treatment control, but conventional temperature measurements do not provide 3D temperature information. Treatment planning is a very useful tool to improve treatment quality and substantial progress has been made over the last decade. Thermal modelling is a very important and challenging aspect of hyperthermia treatment planning. Various thermal models have been developed for this purpose, with varying complexity. Since blood perfusion is such an important factor in thermal redistribution of energy in in vivo tissue, thermal simulations are most accurately performed by modelling discrete vasculature. This review describes the progress in thermal modelling with discrete vasculature for the purpose of hyperthermia treatment planning and thermal ablation. There has been significant progress in thermal modelling with discrete vasculature. Recent developments have made real-time simulations possible, which can provide feedback during treatment for improved therapy. Future clinical application of thermal modelling with discrete vasculature in hyperthermia treatment planning is expected to further improve treatment quality. PMID:23738700

Plasmonic photo-thermal therapy (PPTT) | Huang | Alexandria ...

African Journals Online (AJOL)

Photo-thermal therapy (PTT) is a minimally-invasive therapy in which photon energy is converted into heat to kill cancer. Gold nanoparticles absorb light strongly and convert photon energy into heat quickly and efficiently, thereby making them superior contrast agents for PTT. This gold nanoparticle-assisted PTT called ...

A self-adaptive thermal switch array for rapid temperature stabilization under various thermal power inputs

International Nuclear Information System (INIS)

Geng, Xiaobao; Patel, Pragnesh; Narain, Amitabh; Meng, Dennis Desheng

2011-01-01

A self-adaptive thermal switch array (TSA) based on actuation by low-melting-point alloy droplets is reported to stabilize the temperature of a heat-generating microelectromechanical system (MEMS) device at a predetermined range (i.e. the optimal working temperature of the device) with neither a control circuit nor electrical power consumption. When the temperature is below this range, the TSA stays off and works as a thermal insulator. Therefore, the MEMS device can quickly heat itself up to its optimal working temperature during startup. Once this temperature is reached, TSA is automatically turned on to increase the thermal conductance, working as an effective thermal spreader. As a result, the MEMS device tends to stay at its optimal working temperature without complex thermal management components and the associated parasitic power loss. A prototype TSA was fabricated and characterized to prove the concept. The stabilization temperatures under various power inputs have been studied both experimentally and theoretically. Under the increment of power input from 3.8 to 5.8 W, the temperature of the device increased only by 2.5 °C due to the stabilization effect of TSA

Photoacoustic emission from Au nanoparticles arrayed on thermal insulation layer.

Science.gov (United States)

Namura, Kyoko; Suzuki, Motofumi; Nakajima, Kaoru; Kimura, Kenji

2013-04-08

Efficient photoacoustic emission from Au nanoparticles on a porous SiO(2) layer was investigated experimentally and theoretically. The Au nanoparticle arrays/porous SiO(2)/SiO(2)/Ag mirror sandwiches, namely, local plasmon resonators, were prepared by dynamic oblique deposition (DOD). Photoacoustic measurements were performed on the local plasmon resonators, whose optical absorption was varied from 0.03 (3%) to 0.95 by varying the thickness of the dielectric SiO(2) layer. The sample with high absorption (0.95) emitted a sound that was eight times stronger than that emitted by graphite (0.94) and three times stronger than that emitted by the sample without the porous SiO(2) layer (0.93). The contribution of the porous SiO(2) layer to the efficient photoacoustic emission was analyzed by means of a numerical method based on a one-dimensional heat transfer model. The result suggested that the low thermal conductivity of the underlying porous layer reduces the amount of heat escaping from the substrate and contributes to the efficient photoacoustic emission from Au nanoparticle arrays. Because both the thermal conductivity and the spatial distribution of the heat generation can be controlled by DOD, the local plasmon resonators produced by DOD are suitable for the spatio-temporal modulation of the local temperature.

Aligned Carbon Nanotube Arrays Bonded to Solid Graphite Substrates: Thermal Analysis for Future Device Cooling Applications

Directory of Open Access Journals (Sweden)

Betty T. Quinton

2018-05-01

Full Text Available Carbon nanotubes (CNTs are known for high thermal conductivity and have potential use as nano-radiators or heat exchangers. This paper focuses on the thermal performance of carpet-like arrays of vertically aligned CNTs on solid graphite substrates with the idea of investigating their behavior as a function of carpet dimensions and predicting their performance as thermal interface material (TIM for electronic device cooling. Vertically aligned CNTs were grown on highly oriented pyrolytic graphite (HOPG substrate, which creates a robust and durable all-carbon hierarchical structure. The multi-layer thermal analysis approach using Netzsch laser flash analysis system was used to evaluate their performance as a function of carpet height, from which their thermal properties can be determined. It was seen that the thermal resistance of the CNT array varies linearly with CNT carpet height, providing a unique way of decoupling the properties of the CNT carpet from its interface. This data was used to estimate the thermal conductivity of individual multi-walled nanotube strands in this carpet, which was about 35 W/m-K. The influence of CNT carpet parameters (aerial density, diameter, and length on thermal resistance of the CNT carpet and its potential advantages and limitations as an integrated TIM are discussed.

Modelling of the thermal parameters of high-power linear laser-diode arrays. Two-dimensional transient model

International Nuclear Information System (INIS)

Bezotosnyi, V V; Kumykov, Kh Kh

1998-01-01

A two-dimensional transient thermal model of an injection laser is developed. This model makes it possible to analyse the temperature profiles in pulsed and cw stripe lasers with an arbitrary width of the stripe contact, and also in linear laser-diode arrays. This can be done for any durations and repetition rates of the pump pulses. The model can also be applied to two-dimensional laser-diode arrays operating quasicontinuously. An analysis is reported of the influence of various structural parameters of a diode array on the thermal regime of a single laser. The temperature distributions along the cavity axis are investigated for different variants of mounting a crystal on a heat sink. It is found that the temperature drop along the cavity length in cw and quasi-cw laser diodes may exceed 20%. (lasers)

Effects of thermal annealing temperature and duration on hydrothermally grown ZnO nanorod arrays

Energy Technology Data Exchange (ETDEWEB)

Zhao, X.Q.; Kim, C.R.; Lee, J.Y.; Shin, C.M.; Heo, J.H.; Leem, J.Y. [Department of Nano Systems Engineering, Center for Nano Manufacturing, Inje University, Obang-dong, Gimhae, Gyeongnam 621-749 (Korea, Republic of); Ryu, H. [Department of Nano Systems Engineering, Center for Nano Manufacturing, Inje University, Obang-dong, Gimhae, Gyeongnam 621-749 (Korea, Republic of)], E-mail: hhryu@inje.ac.kr; Chang, J.H. [Major of Nano Semiconductor, Korea Maritime University, 1 Dongsam-dong, Yeongdo-Ku, Busan 606-791 (Korea, Republic of); Lee, H.C. [Department of Mechatronics Engineering, Korea Maritime University, 1 Dongsam-dong, Yeongdo-Ku, Busan 606-791 (Korea, Republic of); Son, C.S. [Department of Electronic Materials Engineering, Silla University, Gwaebeop-dong, Sasang-gu, Busan 617-736 (Korea, Republic of); Shin, B.C.; Lee, W.J. [Department of Nano Engineering, Dong-Eui University, 995 Eomgwangno, Busanjin-gu, Busan 614-714 (Korea, Republic of); Jung, W.G. [School of Advanced Materials Engineering, Kookmin University, 861-1, Jeongneung-dong, Seongbuk-gu, Seoul 136-702 (Korea, Republic of); Tan, S.T. [Institute of Microelectronics, 11 Science Park Road, Science Park II, Singapore 117685 (Singapore); Zhao, J.L. [School of Electrical and Electronic Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798 (Singapore); Sun, X.W. [Institute of Microelectronics, 11 Science Park Road, Science Park II, Singapore 117685 (Singapore); School of Electrical and Electronic Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798 (Singapore)

2009-03-15

In this study, the effects of thermal annealing temperature and duration on ZnO nanorod arrays fabricated by hydrothermal method were investigated. The annealed ZnO/Si(1 1 1) substrate was used for ZnO nanorod array growth. The effects of annealing treatment on the structural and optical properties were investigated by scanning electron microscopy, X-ray diffraction, and room-temperature photoluminescence measurements. With the annealing temperature of 750 {sup o}C and the annealing duration of 10 min, both the structural and optical properties of the ZnO nanorod arrays improved significantly, as indicated in the X-ray diffraction and photoluminescence measurement.

Thermal wave interference with high-power VCSEL arrays for locating vertically oriented subsurface defects

Science.gov (United States)

Thiel, Erik; Kreutzbruck, Marc; Studemund, Taarna; Ziegler, Mathias

2018-04-01

Among the photothermal methods, full-field thermal imaging is used to characterize materials, to determine thicknesses of layers, or to find inhomogeneities such as voids or cracks. The use of classical light sources such as flash lamps (impulse heating) or halogen lamps (modulated heating) led to a variety of nondestructive testing methods, in particular, lock-in and flash-thermography. In vertical-cavity surface-emitting lasers (VCSELs), laser light is emitted perpendicularly to the surface with a symmetrical beam profile. Due to the vertical structure, they can be arranged in large arrays of many thousands of individual lasers, which allows power scaling into the kilowatt range. Recently, a high-power yet very compact version of such a VCSEL-array became available that offers both the fast timing behavior of a laser as well as the large illumination area of a lamp. Moreover, it allows a spatial and temporal control of the heating because individual parts of the array can be controlled arbitrarily in frequency, amplitude, and phase. In conjunction with a fast infrared camera, such structured heating opens up a field of novel thermal imaging and testing methods. As a first demonstration of this approach, we chose a testing problem very challenging to conventional thermal infrared testing: The detection of very thin subsurface defects perpendicularly oriented to the surface of metallic samples. First, we generate destructively interfering thermal wave fields, which are then affected by the presence of defects within their reach. It turned out that this technique allows highly sensitive detection of subsurface defects down to depths in excess of the usual thermographic rule of thumb, with no need for a reference or surface preparation.

Performance of a thermal imager employing a hybrid pyroelectric detector array with MOSFET readout

International Nuclear Information System (INIS)

Watton, R.; Mansi, M.V.

1988-01-01

A thermal imager employing a two-dimensional hybrid array of pyroelectric detectors with MOSFET readout has been built. The design and theoretical performance of the detector are discussed, and the results of performance measurements are presented. 8 references

Control of thermal therapies with moving power deposition field

International Nuclear Information System (INIS)

Arora, Dhiraj; Minor, Mark A; Skliar, Mikhail; Roemer, Robert B

2006-01-01

A thermal therapy feedback control approach to control thermal dose using a moving power deposition field is developed and evaluated using simulations. A normal tissue safety objective is incorporated in the controller design by imposing constraints on temperature elevations at selected normal tissue locations. The proposed control technique consists of two stages. The first stage uses a model-based sliding mode controller that dynamically generates an 'ideal' power deposition profile which is generally unrealizable with available heating modalities. Subsequently, in order to approximately realize this spatially distributed idealized power deposition, a constrained quadratic optimizer is implemented to compute intensities and dwell times for a set of pre-selected power deposition fields created by a scanned focused transducer. The dwell times for various power deposition profiles are dynamically generated online as opposed to the commonly employed a priori-decided heating strategies. Dynamic intensity and trajectory generation safeguards the treatment outcome against modelling uncertainties and unknown disturbances. The controller is designed to enforce simultaneous activation of multiple normal tissue temperature constraints by rapidly switching between various power deposition profiles. The hypothesis behind the controller design is that the simultaneous activation of multiple constraints substantially reduces treatment time without compromising normal tissue safety. The controller performance and robustness with respect to parameter uncertainties is evaluated using simulations. The results demonstrate that the proposed controller can successfully deliver the desired thermal dose to the target while maintaining the temperatures at the user-specified normal tissue locations at or below the maximum allowable values. Although demonstrated for the case of a scanned focused ultrasound transducer, the developed approach can be extended to other heating modalities with

Spatio-temporal chaos and thermal noise in Josephson junction series arrays

International Nuclear Information System (INIS)

Dominguez, D.; Cerdeira, H.A.

1995-01-01

We study underdamped Josephson junction series arrays that are globally coupled through a resistive shunting load and driven by an rf bias current. We find that they can be an experimental realization of many phenomena currently studied in globally coupled logistic map. Depending on the bias current the array can show Shapiro steps but also spatio-temporal chaos or ''turbulence'' in the IV characteristics. In the turbulent phase there is a saturation of the broad band noise for a large number of junctions. This corresponds to a break down of the law of large numbers as seen in globally coupled maps. We study this phenomenon as a function of thermal noise. We find that when increasing the temperature the broad band noise decreases. (author). 8 refs, 1 fig

Additive model for thermal comfort generated by matrix experiment using orthogonal array

Energy Technology Data Exchange (ETDEWEB)

Hwang, Reuy-Lung [Department of Occupational Safety and Health, China Medical University, 91 Huseh-shin Road, Taichung 404 (China); Lin, Tzu-Ping [Department of Leisure Planning, National Formosa University, 64 Wen-hua Road, Huwei, Yunlin 632 (China); Liang, Han-Hsi [Department of Architecture, National United University, No. 1, Lien Da, Kung-Ching Li, Miaoli 360 (China); Yang, Kuan-Hsiug; Yeh, Tsung-Chyn [Department of Mechanical and Electro-Mechanical Engineering, National Sun Yet-Sen University, No. 91, Lien-hai Road, Kaohsiung (China)

2009-08-15

In addition to ensuring the thermal comfort of occupants, monitoring and controlling indoor thermal environments can reduce the energy consumed by air conditioning systems. This study develops an additive model for predicting thermal comfort with rapid and simple arithmetic calculations. The advantage of the additive model is its comprehensibility to administrators of air conditioning systems, who are unfamiliar with the PMV-PPD model but want to adjust an indoor environment to save energy without generating complaints of discomfort from occupants. In order to generate the additive model, a laboratory chamber experiment based on matrix experiment using orthogonal array, was performed. By applying the analysis of variance on observed thermal sensation votes and percentage of dissatisfaction, the factor effects of environmental variables that account for the additive model were determined. Additionally, the applicability of the PMV-PPD model in hot and humid climates is discussed in this study, based on experimental results. (author)

Thermal Molding of Organic Thin-Film Transistor Arrays on Curved Surfaces.

Science.gov (United States)

Sakai, Masatoshi; Watanabe, Kento; Ishimine, Hiroto; Okada, Yugo; Yamauchi, Hiroshi; Sadamitsu, Yuichi; Kudo, Kazuhiro

2017-12-01

In this work, a thermal molding technique is proposed for the fabrication of plastic electronics on curved surfaces, enabling the preparation of plastic films with freely designed shapes. The induced strain distribution observed in poly(ethylene naphthalate) films when planar sheets were deformed into hemispherical surfaces clearly indicated that natural thermal contraction played an important role in the formation of the curved surface. A fingertip-shaped organic thin-film transistor array molded from a real human finger was fabricated, and slight deformation induced by touching an object was detected from the drain current response. This type of device will lead to the development of robot fingers equipped with a sensitive tactile sense for precision work such as palpation or surgery.

Thermal imager based on the array light sensor device of 128×128 CdHgTe-photodiodes

Directory of Open Access Journals (Sweden)

Reva V. P.

2010-08-01

Full Text Available The results of investigation of developed thermal imager for middle (3—5 µm infrared region are presented and its applications features are discussed. The thermal imager consists of cooled to 80 K 128×128 diodes focal plane array on the base of cadmium–mercury–telluride compound and cryostat with temperature checking system. The photodiode array is bonded with readout device (silicon focal processor via indium microcontacts. The measured average value of noise equivalent temperature difference was NETD= 20±4 mK (background radiation temperature T = 300 K, field of view 2θ = 180°, the cooled diaphragm was not used.

Performance study of solar cell arrays based on a Trough Concentrating Photovoltaic/Thermal system

International Nuclear Information System (INIS)

Li, Ming; Ji, Xu; Li, Guoliang; Wei, Shengxian; Li, YingFeng; Shi, Feng

2011-01-01

Highlights: → The performances of solar cell arrays based on a Trough Concentrating Photovoltaic/Thermal (TCPV/T) system have been studied. → The optimum concentration ratios for the single crystalline silicon cell, the Super cells and the GaAs cells were studied by experiments. → The influences between the solar cell's performance and the series resistances, the working temperature, solar irradiation intensity were explored. - Abstract: The performances of solar cell arrays based on a Trough Concentrating Photovoltaic/Thermal (TCPV/T) system have been studied via both experiment and theoretical calculation. The I-V characteristics of the solar cell arrays and the output performances of the TCPV/T system demonstrated that among the investigated four types of solar cell arrays, the triple junction GaAs cells possessed good performance characteristics and the polysilicon cells exhibited poor performance characteristics under concentrating conditions. The optimum concentration ratios for the single crystalline silicon cell, the Super cells and the GaAs cells were also studied by experiments. The optimum concentration ratios for the single crystalline silicon cells and Super cells were 4.23 and 8.46 respectively, and the triple junction GaAs cells could work well at higher concentration ratio. Besides, some theoretical calculations and experiments were performed to explore the influences of the series resistances and the working temperature. When the series resistances R s changed from 0 Ω to 1 Ω, the maximum power P m of the single crystalline silicon, the polycrystalline silicon, the Super cell and the GaAs cell arrays decreased by 67.78%, 74.93%, 77.30% and 58.07% respectively. When the cell temperature increased by 1 K, the short circuit current of the four types of solar cell arrays decreased by 0.11818 A, 0.05364 A, 0.01387 A and 0.00215 A respectively. The research results demonstrated that the output performance of the solar cell arrays with lower

The utility of sparse 2D fully electronically steerable focused ultrasound phased arrays for thermal surgery: a simulation study

International Nuclear Information System (INIS)

Ellens, Nicholas; Pulkkinen, Aki; Song Junho; Hynynen, Kullervo

2011-01-01

Sparse arrays are widely used in diagnostic ultrasound for their strong performance and relative technical simplicity. This simulation study assessed the efficacy of phased arrays of varied sparseness for thermal surgery, especially with regard to power consumption and near-field heating. It employs a linear ultrasound propagation model and a semi-analytical solution to the Pennes' bioheat transfer equation. The basic design had 4912 cylindrical transducers (500 kHz) arranged on a flat 12 cm disk (1.5 mm spacing). This array was compared to randomly-thinned sparse arrays with 75%, 50% and 25% populations. Temperature elevations of 60 and 70 deg. C were induced in sonication times of 5-20 s, at foci spanning depths of 50-150 mm and radii of 0-60 mm. The sparse arrays produced nearly indistinguishable focal patterns but, averaged across the foci, required 132%, 200% and 393% of the power of the full array, respectively, applied through fewer transducer elements. Comparable results were found at 1 MHz from equivalent arrays. Simulated lesions were formed (thermal dose ≥ 240 equivalent minutes at 43 deg. C (T 43 )) and 'transition' and 'unsafe' regions (both defined as 5 min 43 < 240 min) were identified, the former immediately surrounding the lesion and the latter anywhere else. At a depth of 100 mm, sparse arrays were found to produce comparable lesions to the full array at the focus, but 'unsafe', over-heated near-field regions after some ablated lesion volume: about 12 mL for the 25% array, around 100 mL for the 50% array, while the 75% and full arrays produced 150 mL lesions safely.

A practical dimensionless equation for the thermal conductivity of carbon nanotubes and CNT arrays

Directory of Open Access Journals (Sweden)

Qiang Chen

2014-05-01

Full Text Available Experimental results reported in the last decade on the thermal conductivity of carbon nanotubes (CNTs have shown a fairly divergent behavior. An underlying intrinsic consistency was believed to exist in spite of the divergence in the thermal conductivity data of various CNTs. A dimenisonless equation that describes the temperature dependence of thermal conductivity was derived by introducing reduced forms relative to a chosen reference point. This equation can serve as a practical approximation to characterize the conductivity of individual CNT with different structural parameters as well as bulk CNT arrays with different bundle configurations. Comparison of predictions by the equation and historical measurements showed good agreements within their uncertainties.

The impact of thermal wave characteristics on thermal dose distribution during thermal therapy: A numerical study

International Nuclear Information System (INIS)

Shih, T.-C.; Kou, H.-S.; Liauh, C.-T.; Lin, W.-L.

2005-01-01

The aim of this study was to investigate the effects of the propagation speed of a thermal wave in terms of the thermal relaxation time on the temperature/thermal dose distributions in living tissue during thermal therapies. The temperature field in tissue was solved by the finite difference method, and the thermal dose was calculated from the formulation proposed by Sapareto and Dewey [Int. J. Radiat. Oncol. Biol. Phys. 10, 787-800 (1984)]. Under the same total deposited energy, for a rapid heating process the time lagging behavior of the peak temperature became pronounced and the level of the peak temperature was decreased with increasing the thermal relaxation time. When the heating duration was longer than the thermal relaxation time of tissues, there was no significant difference between the thermal dose distributions with/without considering the effect of the thermal relaxation time. In other words, when the heating duration is comparable to or shorter than the thermal relaxation time of tissue, the results of the wave bioheat transfer equation (WBHTE) are fully different from that of the Pennes' bioheat transfer equation (PBHTE). Besides, for a rapid heating process the dimension of thermal lesion was still significantly affected by perfusion, because this is what is predicted by the WBHTE but not by the PBHTE, i.e., the wave feature of the temperature field cannot fully be predicted by the PBHTE

Thermally responsive silicon nanowire arrays for native/denatured-protein separation

International Nuclear Information System (INIS)

Wang Hongwei; Wang Yanwei; Yuan Lin; Wang Lei; Yang Weikang; Wu Zhaoqiang; Li Dan; Chen Hong

2013-01-01

We present our findings of the selective adsorption of native and denatured proteins onto thermally responsive, native-protein resistant poly(N-isopropylacrylamide) (PNIPAAm) decorated silicon nanowire arrays (SiNWAs). The PNIPAAm–SiNWAs surface, which shows very low levels of native-protein adsorption, favors the adsorption of denatured proteins. The amount of denatured-protein adsorption is higher at temperatures above the lower critical solution temperature (LCST) of PNIPAAm. Temperature cycling surrounding the LCST, which ensures against thermal denaturation of native proteins, further increases the amount of denatured-protein adsorption. Moreover, the PNIPAAm–SiNWAs surface is able to selectively adsorb denatured protein even from mixtures of different protein species; meanwhile, the amount of native proteins in solution is kept nearly at its original level. It is believed that these results will not only enrich current understanding of protein interactions with PNIPAAm-modified SiNWAs surfaces, but may also stimulate applications of PNIPAAm–SiNWAs surfaces for native/denatured protein separation. (paper)

Measuring Millimeter Wave of Cold Atmospheric Plasma Array by a Novel Technique

Directory of Open Access Journals (Sweden)

Bryon Eckert

2016-08-01

Full Text Available An unexplained repulsive force occasionally observed during non-thermal plasma treatment of large infections may point the way to an efficient mechanism for characterizing biofield energy. Ambient pressure air plasma in non-thermal equilibrium creates areas of localized population inversion, causing spontaneous emission at magnetic dipole rotational resonance lines. For O2, many of these lines occur in the 60 GHz frequency range. This experiment examines a possible link between the fine resonance frequencies of oxygen in the 60 GHz region, and the therapeutic frequencies used in Russian non-thermal EHF therapy. This paper also explores the feasibility of using a plasma array for biological torsion field characterization. An array of several hundred non-thermal plasma plumes are placed directly in front of a circular horn. A switchable circular polarizer is used to select left hand circular, linear or right hand circular polarization. A low noise frequency converter allows a noise temperature of less than 1150 K. A frequency scan and averaging algorithm is developed to characterize noise temperature versus frequency, comparing signal and noise levels between plasma on and plasma off, and switching polarization sense. An experimental setup is proposed as a proof of concept for detecting signals from the plasma array, while a practical laboratory tool is also proposed.

Intravenous Laser Therapy in Young Children with Thermal Injuries

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R. V. Bocharov

2014-01-01

Full Text Available Objective: to evaluate the laboratory and clinical effects of combined intravenous laser therapy in young children with thermalinjuries in the acute period of burn disease.Subjects and methods. Forty children whose mean age was 2.67±0.35 years were examined; thermal injuries accounted for 25.05±1.01% of the total body surface area; of them degrees IIIaIIIb was 19.04±0.85%. A comparison group (n=15 received conventional therapy without taking into account and correcting baseline and current hemostasiological disorders. On day 1, a study group (n=25 had programmed anticoagulant therapy and intravenous laser therapy at different radiation frequencies with a Mustang 20002+ laser therapy apparatus (patent for invention No. 2482894 in addition to the conventional therapy. The laser therapy cycle was 6 to 16 sessions. The investigators estimated and compared the following examined parameters: white blood cell count; leukocytic index of intoxication; plasma average mass molecules at a wavelength of 254 nm; toxogenic granularity of neutrophils; wound exudate discharge time; surgical plasty area; and hospitalization time.Results. The positive laboratory and clinical effects of the performed combined intravenous laser therapy in the combined therapy of burn disease in young children were comparatively shown in the study group patients. The significant decrease in the level of an inflammatory response and endogenous intoxication led to a rapider burn wound cleansing, active epithelization, and reduced surgical plasty volumes.Conclusion. Combined intravenous laser therapy signif icantly exerts antiinflammatory and detoxifying effects in young children with 40% thermal injuries in the acute period of burn disease. Abolishing a systemic inflammatory response by combined intravenous laser therapy initiated early regenerative processes in the burn wound and caused reductions in surgical plasty volumes and hospitalization time, which optimizes ther

Comparative study on radon effects and thermal effects on humans in radon hot spring therapy

International Nuclear Information System (INIS)

Yamaoka, K.; Mitsunobu, F.; Hanamoto, K.; Tanizaki, Y.; Sugita, K.; Kohima, S.

2003-01-01

Full text: The radon therapy is used radon ( 222 Rn) gas, which mainly emits alpha-rays, and induces a small amount of active oxygen in the body. Because most of the diseases to which the radon therapy as well as the thermal therapy is applied are related to activated oxygen, in this study the effects of the radioactivity of radon and thermal effects were compared under the room or the hot spring condition with the similar chemical component, using as the parameters which are closely involved in the clinical for radon therapy. In the results, the radon and thermal therapy enhanced the antioxidation function, such as the activities of superoxide dismutase (SOD) and catalase, which inhibit lipid peroxidation and total cholesterol produce in the body. Moreover the therapy enhanced concanavalin A (ConA)-induced mitogen response, and increased the level of CD4, which is the marker of helper T cell, and decreased the level of CD8, which is the common marker of killer T cell and supresser T cell, in the white cell differentiation antigen (CD4/CD8) assay. Furthermore, the therapy increased the levels of alpha atrial natriuretic polypeptide (alpha ANP), beta endorphin, adrenocorticotropic hormone (ACTH), insulin and glucose-phosphate dehydrogenase (G-6-PDH), and decreased the vasopression level. The results were on the whole larger in the radon group than in the thermal group. The findings suggest that the radon therapy more contributes to the prevention of life style-related diseases related to peroxidation reactions and immune depression than thermal therapy. Moreover these indicate what may be a part of the mechanism for the alleviation of hypertension, osteoarthritis (pain) and diabetes mellitus brought about more radon therapy than thermal therapy

Fabrication of a Micro-Needle Array Electrode by Thermal Drawing for Bio-Signals Monitoring.

Science.gov (United States)

Ren, Lei; Jiang, Qing; Chen, Keyun; Chen, Zhipeng; Pan, Chengfeng; Jiang, Lelun

2016-06-17

A novel micro-needle array electrode (MAE) fabricated by thermal drawing and coated with Ti/Au film was proposed for bio-signals monitoring. A simple and effective setup was employed to form glassy-state poly (lactic-co-glycolic acid) (PLGA) into a micro-needle array (MA) by the thermal drawing method. The MA was composed of 6 × 6 micro-needles with an average height of about 500 μm. Electrode-skin interface impedance (EII) was recorded as the insertion force was applied on the MAE. The insertion process of the MAE was also simulated by the finite element method. Results showed that MAE could insert into skin with a relatively low compression force and maintain stable contact impedance between the MAE and skin. Bio-signals, including electromyography (EMG), electrocardiography (ECG), and electroencephalograph (EEG) were also collected. Test results showed that the MAE could record EMG, ECG, and EEG signals with good fidelity in shape and amplitude in comparison with the commercial Ag/AgCl electrodes, which proves that MAE is an alternative electrode for bio-signals monitoring.

Fabrication of a Micro-Needle Array Electrode by Thermal Drawing for Bio-Signals Monitoring

Directory of Open Access Journals (Sweden)

Lei Ren

2016-06-01

Full Text Available A novel micro-needle array electrode (MAE fabricated by thermal drawing and coated with Ti/Au film was proposed for bio-signals monitoring. A simple and effective setup was employed to form glassy-state poly (lactic-co-glycolic acid (PLGA into a micro-needle array (MA by the thermal drawing method. The MA was composed of 6 × 6 micro-needles with an average height of about 500 μm. Electrode-skin interface impedance (EII was recorded as the insertion force was applied on the MAE. The insertion process of the MAE was also simulated by the finite element method. Results showed that MAE could insert into skin with a relatively low compression force and maintain stable contact impedance between the MAE and skin. Bio-signals, including electromyography (EMG, electrocardiography (ECG, and electroencephalograph (EEG were also collected. Test results showed that the MAE could record EMG, ECG, and EEG signals with good fidelity in shape and amplitude in comparison with the commercial Ag/AgCl electrodes, which proves that MAE is an alternative electrode for bio-signals monitoring.

Proposed Use of Zero Bias Diode Arrays as Thermal Electric Noise Rectifiers and Non-Thermal Energy Harvesters

Science.gov (United States)

Valone, Thomas F.

2009-03-01

The well known built-in voltage potential for some select semiconductor p-n junctions and various rectifying devices is proposed to be favorable for generating DC electricity at "zero bias" (with no DC bias voltage applied) in the presence of Johnson noise or 1/f noise which originates from the quantum vacuum (Koch et al., 1982). The 1982 Koch discovery that certain solid state devices exhibit measurable quantum noise has also recently been labeled a finding of dark energy in the lab (Beck and Mackey, 2004). Tunnel diodes are a class of rectifiers that are qualified and some have been credited with conducting only because of quantum fluctuations. Microwave diodes are also good choices since many are designed for zero bias operation. A completely passive, unamplified zero bias diode converter/detector for millimeter (GHz) waves was developed by HRL Labs in 2006 under a DARPA contract, utilizing a Sb-based "backward tunnel diode" (BTD). It is reported to be a "true zero-bias diode." It was developed for a "field radiometer" to "collect thermally radiated power" (in other words, 'night vision'). The diode array mounting allows a feed from horn antenna, which functions as a passive concentrating amplifier. An important clue is the "noise equivalent power" of 1.1 pW per root hertz and the "noise equivalent temperature difference" of 10° K, which indicate sensitivity to Johnson noise (Lynch, et al., 2006). There also have been other inventions such as "single electron transistors" that also have "the highest signal to noise ratio" near zero bias. Furthermore, "ultrasensitive" devices that convert radio frequencies have been invented that operate at outer space temperatures (3 degrees above zero point: 3° K). These devices are tiny nanotech devices which are suitable for assembly in parallel circuits (such as a 2-D array) to possibly produce zero point energy direct current electricity with significant power density (Brenning et al., 2006). Photovoltaic p-n junction

Transient three-dimensional thermal-hydraulic analysis of nuclear reactor fuel rod arrays: general equations and numerical scheme

International Nuclear Information System (INIS)

Wnek, W.J.; Ramshaw, J.D.; Trapp, J.A.; Hughes, E.D.; Solbrig, C.W.

1975-11-01

A mathematical model and a numerical solution scheme for thermal-hydraulic analysis of fuel rod arrays are given. The model alleviates the two major deficiencies associated with existing rod array analysis models, that of a correct transverse momentum equation and the capability of handling reversing and circulatory flows. Possible applications of the model include steady state and transient subchannel calculations as well as analysis of flows in heat exchangers, other engineering equipment, and porous media

Ordering and thermal excitations in dipolar coupled single domain magnet arrays (Presentation Recording)

Science.gov (United States)

Östman, Erik; Arnalds, Unnar; Kapaklis, Vassilios; Hjörvarsson, Björgvin

2015-09-01

For a small island of a magnetic material the magnetic state of the island is mainly determined by the exchange interaction and the shape anisotropy. Two or more islands placed in close proximity will interact through dipolar interactions. The state of a large system will thus be dictated by interactions at both these length scales. Enabling internal thermal fluctuations, e.g. by the choice of material, of the individual islands allows for the study of thermal ordering in extended nano-patterned magnetic arrays [1,2]. As a result nano-magnetic arrays represent an ideal playground for the study of physical model systems. Here we present three different studies all having used magneto-optical imaging techniques to observe, in real space, the order of the systems. The first study is done on a square lattice of circular islands. The remanent magnetic state of each island is a magnetic vortex structure and we can study the temperature dependence of the vortex nucleation and annihilation fields [3]. The second are long chains of dipolar coupled elongated islands where the magnetization direction in each island only can point in one of two possible directions. This creates a system which in many ways mimics the Ising model [4] and we can relate the correlation length to the temperature. The third one is a spin ice system where elongated islands are placed in a square lattice. Thermal excitations in such systems resemble magnetic monopoles [2] and we can investigate their properties as a function of temperature and lattice parameters. [1] V. Kapaklis et al., New J. Phys. 14, 035009 (2012) [2] V. Kapaklis et al., Nature Nanotech 9, 514(2014) [3] E. Östman et al.,New J. Phys. 16, 053002 (2014) [4] E. Östman et al.,Thermal ordering in mesoscopic Ising chains, In manuscript.

Calculating electrical and thermal characteristics of multiple PV array configurations installed in the tropics

International Nuclear Information System (INIS)

Effendy Ya’acob, M.; Hizam, Hashim; Htay, Myo Than; Radzi, M. Amran M.; Khatib, Tamer; Bakri A, M.

2013-01-01

Highlights: • Electrical and temperature characteristics of multiple PV array configurations. • Ten months tropical field analysis implying SNL model for array parameter. • Review on T c equations and GEV analysis for rapid fluctuating environmental data. • CPV array projects the highest ΔT of 2.72 °C with G e of 0.36 W/m 2 . • Fixed flat array produces highest parameter values of I sc , V oc , I mp , V mp and P mp . - Abstract: This study intends to define the electrical characteristics and temperature equations of PV array installed in the tropics based on Sandia National Laboratory (SNL) model. Ten units of 1 kW rated PV array namely Fixed Flat (FF), Tracking Flat (TF) and Concentrating (CPV) have been installed at Universiti Putra Malaysia (UPM), Serdang District, Malaysia at the coordinate of 2°59′20′′N:101°43′30′′E with tropical-based ground conditions. Electrical characteristics are the main elements of contributions where five operating conditions for CEEG PV Module are applied based on the SNL model to produce array parameter values. It is found that FF array projects the highest operating value of 12.06 A (I sc ), 11.55 A (I mp ), 524.78 V (V oc ), 89.5 V (V mp ), and 1033.7 W (P mp ) with good regression fit and strong correlation R 2 of more than 0.5. The versatility and accuracy of this work have been validated and applied for three different types of PV array system installed in the equatorial doldrum spot of uniform temperature–irradiance, high in humidity–rainfall and generally light wind field conditions. The parameters are calculated using filtered field data sampled at STC of 5% tolerance. Focal point of calculating array temperature (T array ) as means of thermal effect on multiple PV array configurations is highlighted based on recent study on T c equations and Generalized Extreme Value (GEV) analysis using field data at site

Optical spins and nano-antenna array for magnetic therapy.

Science.gov (United States)

Thammawongsa, N; Mitatha, S; Yupapin, P P

2013-09-01

Magnetic therapy is an alternative medicine practice involving the use of magnetic fields subjected to certain parts of the body and stimulates healing from a range of health problems. In this paper, an embedded nano-antenna system using the optical spins generated from a particular configuration of microrings (PANDA) is proposed. The orthogonal solitons pairs corresponding to the left-hand and right-hand optical solitons (photons) produced from dark-bright soliton conversion can be simultaneously detected within the system at the output ports. Two possible spin states which are assigned as angular momentum of either +ħ or -ħ will be absorbed by an object whenever this set of orthogonal solitons is imparted to the object. Magnetic moments could indeed arise from the intrinsic property of spins. By controlling some important parameters of the system such as soliton input power, coupling coefficients and sizes of rings, output signals from microring resonator system can be tuned and optimized to be used as magnetic therapy array.

Ultrasound cylindrical phased array for transoesophageal thermal therapy: initial studies

International Nuclear Information System (INIS)

Melodelima, David; Lafon, Cyril; Prat, Frederic; Birer, Alain; Cathignol, Dominique

2002-01-01

This work was undertaken to investigate the feasibility of constructing a cylindrical phased array composed of 64 elements spread around the periphery (OD 10.6 mm) for transoesophageal ultrasound thermotherapy. The underlying operating principle of this applicator is to rotate a plane ultrasound beam electronically. For this purpose, eight adjacent transducers were successively excited with appropriate delay times so as to generate a plane wave. The exposure direction was changed by exciting a different set of eight elements. For these feasibility studies, we used a cylindrical prototype (OD 10.6 mm) composed of 16 elementary transducers distributed over a quarter of the cylinder, all operating at 4.55 MHz. The active part was mechanically reinforced by a rigid damper structure behind the transducers. It was shown that an ultrasound field similar to that emitted by a plane transducer could be generated. Ex vivo experiments on pig's liver demonstrated that the ultrasound beam could be accurately rotated to generate sector-based lesions to a suitable depth (up to 19 mm). Throughout these experiments, exposures lasting 20 s were delivered at an acoustic intensity of 17 W cm -2 . By varying the power from exposure to exposure, the depth of the lesion at different angles could be controlled

Physics of epi-thermal boron neutron capture therapy (epi-thermal BNCT).

Science.gov (United States)

Seki, Ryoichi; Wakisaka, Yushi; Morimoto, Nami; Takashina, Masaaki; Koizumi, Masahiko; Toki, Hiroshi; Fukuda, Mitsuhiro

2017-12-01

The physics of epi-thermal neutrons in the human body is discussed in the effort to clarify the nature of the unique radiologic properties of boron neutron capture therapy (BNCT). This discussion leads to the computational method of Monte Carlo simulation in BNCT. The method is discussed through two examples based on model phantoms. The physics is kept at an introductory level in the discussion in this tutorial review.

Thermal performance of solar air collection-storage system with phase change material based on flat micro-heat pipe arrays

International Nuclear Information System (INIS)

Wang, Teng-yue; Diao, Yan-hua; Zhu, Ting-ting; Zhao, Yao-hua; Liu, Jing; Wei, Xiang-qian

2017-01-01

Highlights: • A new type of solar air collection-storage thermal system with PCM is proposed. • Flat micro-heat pipe array is used as the core heat transfer element. • Air volume flow rate influence charging and discharging time obviously. • Air-side thermal resistance dominates during charging and discharging. - Abstract: In this study, a new type of solar air collection-storage thermal system (ACSTS) with phase change material (PCM) is designed using flat micro-heat pipe arrays (FMHPA) as the heat transfer core element. The solar air collector comprises FMHPA and vacuum tubes. The latent thermal storage device (LTSD) utilizes lauric acid, which is a type of fatty acid, as PCM. The experiments test the performance of collector efficiency and charging and discharging time of thermal storage device through different air volume flow rates. After a range of tests, high air volume flow rate is concluded to contribute to high collector efficiency and short charging and discharging time and enhance instantaneous heat transfer, whereas an air volume flow rate of 60 m"3/h during discharging provides a steady outlet temperature. The cumulative heat transfer during discharging is between 4210 and 4300 kJ.

Heat transfer behavior including thermal wake effects in forced air cooling of arrays of rectangular blocks

International Nuclear Information System (INIS)

Sridhar, S.; Faghri, M.; Lessmann, R.C.

1990-01-01

Experiments have been carried out to study thermal wake effects in arrays of rectangular blocks encountered in electronic equipment. Data were obtained for a series of channel heights and flow velocities. The temperature rise due to wake effects behind a single heated module was found to be fairly independent of the channel height and the position of the heated block, for a given approach velocity. The adiabatic temperature rise data for a module due to a heated element immediately upstream of it for different inter-module spacings were found to correlate well in terms of a new parameter called the surface packing density. This paper reports that it was reported by the authors in an earlier paper that both the adiabatic heat transfer coefficient nd pressure-drop data for regular in-line arrays correlated well in terms of a composite geometric parameter called the column packing density. These experiments have been extended to a higher Reynolds number. Empirical correlations are presented here for friction factor and Nusselt number in terms of the volume packing density, and for the thermal wake effects in terms of the surface packing density. Data from literature for arrays with widely different geometric parameters are shown to agree with these correlations

A 1372-element Large Scale Hemispherical Ultrasound Phased Array Transducer for Noninvasive Transcranial Therapy

International Nuclear Information System (INIS)

Song, Junho; Hynynen, Kullervo

2009-01-01

Noninvasive transcranial therapy using high intensity focused ultrasound transducers has attracted high interest as a promising new modality for the treatments of brain related diseases. We describe the development of a 1372 element large scale hemispherical ultrasound phased array transducer operating at a resonant frequency of 306 kHz. The hemispherical array has a diameter of 31 cm and a 15.5 cm radius of curvature. It is constructed with piezoelectric (PZT-4) tube elements of a 10 mm in diameter, 6 mm in length and 1.4 mm wall thickness. Each element is quasi-air backed by attaching a cork-rubber membrane on the back of the element. The acoustic efficiency of the element is determined to be approximately 50%. The large number of the elements delivers high power ultrasound and offers better beam steering and focusing capability. Comparisons of sound pressure-squared field measurements with theoretical calculations in water show that the array provides good beam steering and tight focusing capability over an efficient volume of approximately 100x100x80 mm 3 with nominal focal spot size of approximately 2.3 mm in diameter at -6 dB. We also present its beam steering and focusing capability through an ex vivo human skull by measuring pressure-squared amplitude after phase corrections. These measurements show the same efficient volume range and focal spot sizes at -6 dB as the ones in water without the skull present. These results indicate that the array is sufficient for use in noninvasive transcranial ultrasound therapy.

Thermal dewetting with a chemically heterogeneous nano-template for self-assembled L1(0) FePt nanoparticle arrays.

Science.gov (United States)

Wang, Liang-Wei; Cheng, Chung-Fu; Liao, Jung-Wei; Wang, Chiu-Yen; Wang, Ding-Shuo; Huang, Kuo-Feng; Lin, Tzu-Ying; Ho, Rong-Ming; Chen, Lih-Juann; Lai, Chih-Huang

2016-02-21

A design for the fabrication of metallic nanoparticles is presented by thermal dewetting with a chemically heterogeneous nano-template. For the template, we fabricate a nanostructured polystyrene-b-polydimethylsiloxane (PS-b-PDMS) film on a Si|SiO2 substrate, followed by a thermal annealing and reactive ion etching (RIE) process. This gives a template composed of an ordered hexagonal array of SiOC hemispheres emerging in the polystyrene matrix. After the deposition of a FePt film on this template, we utilize the rapid thermal annealing (RTA) process, which provides in-plane stress, to achieve thermal dewetting and structural ordering of FePt simultaneously. Since the template is composed of different composition surfaces with periodically varied morphologies, it offers more tuning knobs to manipulate the nanostructures. We show that both the decrease in the area of the PS matrix and the increase in the strain energy relaxation transfer the dewetted pattern from the randomly distributed nanoparticles into a hexagonal periodic array of L10 FePt nanoparticles. Transmission electron microscopy with the in situ heating stage reveals the evolution of the dewetting process, and confirms that the positions of nanoparticles are aligned with those of the SiOC hemispheres. The nanoparticles formed by this template-dewetting show an average diameter and center-to-center distance of 19.30 ± 2.09 nm and 39.85 ± 4.80 nm, respectively. The hexagonal array of FePt nanoparticles reveals a large coercivity of 1.5 T, much larger than the nanoparticles fabricated by top-down approaches. This approach offers an efficient pathway toward self-assembled nanostructures in a wide range of material systems.

A Probabilistic Approach to Predict Thermal Fatigue Life for Ball Grid Array Solder Joints

Science.gov (United States)

Wei, Helin; Wang, Kuisheng

2011-11-01

Numerous studies of the reliability of solder joints have been performed. Most life prediction models are limited to a deterministic approach. However, manufacturing induces uncertainty in the geometry parameters of solder joints, and the environmental temperature varies widely due to end-user diversity, creating uncertainties in the reliability of solder joints. In this study, a methodology for accounting for variation in the lifetime prediction for lead-free solder joints of ball grid array packages (PBGA) is demonstrated. The key aspects of the solder joint parameters and the cyclic temperature range related to reliability are involved. Probabilistic solutions of the inelastic strain range and thermal fatigue life based on the Engelmaier model are developed to determine the probability of solder joint failure. The results indicate that the standard deviation increases significantly when more random variations are involved. Using the probabilistic method, the influence of each variable on the thermal fatigue life is quantified. This information can be used to optimize product design and process validation acceptance criteria. The probabilistic approach creates the opportunity to identify the root causes of failed samples from product fatigue tests and field returns. The method can be applied to better understand how variation affects parameters of interest in an electronic package design with area array interconnections.

Analysis of thermal dispersion in an array of parallel plates with fully-developed laminar flow

International Nuclear Information System (INIS)

Xu Jiaying; Lu Tianjian; Hodson, Howard P.; Fleck, Norman A.

2010-01-01

The effect of thermal dispersion upon heat transfer across a periodic array of parallel plates is studied. Three basic heat transfer problems are addressed, each for steady, fully-developed, laminar fluid flow: (a) transient heat transfer due to an arbitrary initial temperature distribution within the fluid, (b) steady heat transfer with constant heat flux on all plate surfaces, and (c) steady heat transfer with constant wall temperatures. For problems (a) and (b), the effective thermal dispersivity scales with the Peclet number Pe according to 1 + CPe 2 , where the coefficient C is independent of Pe. For problem (c) the coefficient C is a function of Pe.

Cancer therapy using non-thermal atmospheric pressure plasma with ultra-high electron density

International Nuclear Information System (INIS)

Tanaka, Hiromasa; Mizuno, Masaaki; Toyokuni, Shinya; Maruyama, Shoichi; Kodera, Yasuhiro; Terasaki, Hiroko; Adachi, Tetsuo; Kato, Masashi; Kikkawa, Fumitaka; Hori, Masaru

2015-01-01

Cancer therapy using non-thermal atmospheric pressure plasma is a big challenge in plasma medicine. Reactive species generated from plasma are key factors for treating cancer cells, and thus, non-thermal atmospheric pressure plasma with high electron density has been developed and applied for cancer treatment. Various cancer cell lines have been treated with plasma, and non-thermal atmospheric plasma clearly has anti-tumor effects. Recent innovative studies suggest that plasma can both directly and indirectly affect cells and tissues, and this observation has widened the range of applications. Thus, cancer therapy using non-thermal atmospheric pressure plasma is promising. Animal experiments and understanding the mode of action are essential for clinical application in the future. A new academic field that combines plasma science, the biology of free radicals, and systems biology will be established

Cancer therapy using non-thermal atmospheric pressure plasma with ultra-high electron density

Energy Technology Data Exchange (ETDEWEB)

Tanaka, Hiromasa [Institute of Innovation for Future Society, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Center for Advanced Medicine and Clinical Research, Nagoya University Graduate School of Medicine, Tsurumai-cho 65, Showa-ku, Nagoya 466-8550 (Japan); Mizuno, Masaaki [Center for Advanced Medicine and Clinical Research, Nagoya University Graduate School of Medicine, Tsurumai-cho 65, Showa-ku, Nagoya 466-8550 (Japan); Toyokuni, Shinya [Department of Pathology and Biological Responses, Nagoya University Graduate School of Medicine, Tsurumai-cho 65, Showa-ku, Nagoya 466-8550 (Japan); Maruyama, Shoichi [Department of Nephrology, Nagoya University Graduate School of Medicine, Tsurumai-cho 65, Showa-ku, Nagoya 466-8550 (Japan); Kodera, Yasuhiro [Department of Gastroenterological Surgery (Surgery II), Nagoya University Graduate School of Medicine, Tsurumai-cho 65, Showa-ku, Nagoya 466-8550 (Japan); Terasaki, Hiroko [Department of Ophthalmology, Nagoya University Graduate School of Medicine, Tsurumai-cho 65, Showa-ku, Nagoya 466-8550 (Japan); Adachi, Tetsuo [Laboratory of Clinical Pharmaceutics, Gifu Pharmaceutical University, 501-1196 Gifu (Japan); Kato, Masashi [Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, Tsurumai-cho 65, Showa-ku, Nagoya 466-8550 (Japan); Kikkawa, Fumitaka [Department of Obstetrics and Gynecology, Nagoya University Graduate School of Medicine, Tsurumai-cho 65, Showa-ku, Nagoya 466-8550 (Japan); Hori, Masaru [Institute of Innovation for Future Society, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan)

2015-12-15

Cancer therapy using non-thermal atmospheric pressure plasma is a big challenge in plasma medicine. Reactive species generated from plasma are key factors for treating cancer cells, and thus, non-thermal atmospheric pressure plasma with high electron density has been developed and applied for cancer treatment. Various cancer cell lines have been treated with plasma, and non-thermal atmospheric plasma clearly has anti-tumor effects. Recent innovative studies suggest that plasma can both directly and indirectly affect cells and tissues, and this observation has widened the range of applications. Thus, cancer therapy using non-thermal atmospheric pressure plasma is promising. Animal experiments and understanding the mode of action are essential for clinical application in the future. A new academic field that combines plasma science, the biology of free radicals, and systems biology will be established.

Thermal Characterisation of Micro Flat Aluminium Heat Pipe Arrays by Varying Working Fluid and Inclination Angle

Directory of Open Access Journals (Sweden)

Guanghan Huang

2018-06-01

Full Text Available A micro heat pipe array is desirable owing to its high heat transfer capacity, compact size, and high surface–volume ratio compared with conventional heat pipes. In this study, micro flat aluminium heat pipe arrays (MF-AHPA were developed and systematically characterised by varying working fluid and inclination angle. Three MF-AHPAs with different working fluids, i.e., acetone, cyclopentane, and n-hexane, were fabricated. The acetone MF-AHPA achieved the best thermal performance. The underlying mechanism is the small flow viscous friction and small shearing force of liquid vapour. Additionally, the experimental results show a strong dependence of MF-AHPAs’ thermal resistance on the orientation due to the gravitational effect on axial liquid distribution. Finally, a criterion is proposed to determine the optimal inclination angle of the MF-AHPA. In the present study, a volumetric fraction (αa,c of 74 ± 7% has been shown to well predict an optimal inclination angle of the MF-AHPAs with various working fluids and heat loads.

Use of a two-dimensional ionization chamber array for proton therapy beam quality assurance

International Nuclear Information System (INIS)

Arjomandy, Bijan; Sahoo, Narayan; Ding Xiaoning; Gillin, Michael

2008-01-01

Two-dimensional ion chamber arrays are primarily used for conventional and intensity modulated radiotherapy quality assurance. There is no commercial device of such type available on the market that is offered for proton therapy quality assurance. We have investigated suitability of the MatriXX, a commercial two-dimensional ion chamber array detector for proton therapy QA. This device is designed to be used for photon and electron therapy QA. The device is equipped with 32x32 parallel plate ion chambers, each with 4.5 mm diam and 7.62 mm center-to-center separation. A 250 MeV proton beam was used to calibrate the dose measured by this device. The water equivalent thickness of the buildup material was determined to be 3.9 mm using a 160 MeV proton beam. Proton beams of different energies were used to measure the reproducibility of dose output and to evaluate the consistency in the beam flatness and symmetry measured by MatriXX. The output measurement results were compared with the clinical commissioning beam data that were obtained using a 0.6 cc Farmer chamber. The agreement was consistently found to be within 1%. The profiles were compared with film dosimetry and also with ion chamber data in water with an excellent agreement. The device is found to be well suited for quality assurance of proton therapy beams. It provides fast two-dimensional dose distribution information in real time with the accuracy comparable to that of ion chamber measurements and film dosimetry

Far infrared thermal detectors for laser radiometry using a carbon nanotube array

Energy Technology Data Exchange (ETDEWEB)

Lehman, John H.; Lee, Bob; Grossman, Erich N.

2011-07-20

We present a description of a 1.5 mm long, vertically aligned carbon nanotube array (VANTA) on a thermopile and separately on a pyroelectric detector. Three VANTA samples, having average lengths of 40 {mu}m, 150 {mu}m, and 1.5 mm were evaluated with respect to reflectance at a laser wavelength of 394 {mu}m(760 GHz), and we found that the reflectance decreases substantially with increasing tube length, ranging from 0.38 to 0.23 to 0.01, respectively. The responsivity of the thermopile by electrical heating (98.4 mA/W) was equal to that by optical heating (98.0 mA/W) within the uncertainty of the measurement. We analyzed the frequency response and temporal response and found a thermal decay period of 500 ms, which is consistent with the specific heat of comparable VANTAs in the literature. The extremely low (0.01) reflectance of the 1.5 mm VANTAs and the fact that the array is readily transferable to the detector's surface is, to our knowledge, unprecedented.

Hyper-thermal neutron irradiation field for neutron capture therapy

International Nuclear Information System (INIS)

Sakurai, Yoshinori; Kobayashi, Tooru; Kanda, Keiji

1994-01-01

The utilization of hyper-thermal neutrons, which have an energy spectrum of a Maxwell distribution higher than the room temperature of 300 K, has been studied in order to improve the thermal neutron flux distribution in a living body for a deep-seated tumor in neutron capture therapy (NCT). Simulation calculations using MCNP-V3 were carried out in order to investigate the characteristics of the hyper-thermal neutron irradiation field. From the results of simulation calculations, the following were confirmed: (i) The irradiation field of the hyper-thermal neutrons is feasible by using some scattering materials with high temperature, such as Be, BeO, C, SiC and ZrH 1.7 . Especially, ZrH 1.7 is thought to be the best material because of good characteristics of up-scattering for thermal neutrons. (ii) The ZrH 1.7 of 1200 K yields the hyper-thermal neutrons of a Maxwell-like distribution at about 2000 K and the treatable depth is about 1.5 cm larger comparing with the irradiation of the thermal neutrons of 300 K. (iii) The contamination by the secondary gamma-rays from the scattering materials can be sufficiently eliminated to the tolerance level for NCT through the bismuth layer, without the larger change of the energy spectrum of hyper-thermal neutrons. ((orig.))

Effect of van der Waals forces on thermal conductance at the interface of a single-wall carbon nanotube array and silicon

Directory of Open Access Journals (Sweden)

Ya Feng

2014-12-01

Full Text Available Molecular dynamics simulations are performed to evaluate the effect of van der Waals forces among single-wall carbon nanotubes (SWNTs on the interfacial thermal conductance between a SWNT array and silicon substrate. First, samples of SWNTs vertically aligned on silicon substrate are simulated, where both the number and arrangement of SWNTs are varied. Results reveal that the interfacial thermal conductance of a SWNT array/Si with van der Waals forces present is higher than when they are absent. To better understand how van der Waals forces affect heat transfer through the interface between SWNTs and silicon, further constructs of one SWNT surrounded by different numbers of other ones are studied, and the results show that the interfacial thermal conductance of the central SWNT increases with increasing van der Waals forces. Through analysis of the covalent bonds and vibrational density of states at the interface, we find that heat transfer across the interface is enhanced with a greater number of chemical bonds and that improved vibrational coupling of the two sides of the interface results in higher interfacial thermal conductance. Van der Waals forces stimulate heat transfer at the interface.

A Micro-Thermal Sensor for Focal Therapy Applications

Science.gov (United States)

Natesan, Harishankar; Hodges, Wyatt; Choi, Jeunghwan; Lubner, Sean; Dames, Chris; Bischof, John

2016-02-01

There is an urgent need for sensors deployed during focal therapies to inform treatment planning and in vivo monitoring in thin tissues. Specifically, the measurement of thermal properties, cooling surface contact, tissue thickness, blood flow and phase change with mm to sub mm accuracy are needed. As a proof of principle, we demonstrate that a micro-thermal sensor based on the supported “3ω” technique can achieve this in vitro under idealized conditions in 0.5 to 2 mm thick tissues relevant to cryoablation of the pulmonary vein (PV). To begin with “3ω” sensors were microfabricated onto flat glass as an idealization of a focal probe surface. The sensor was then used to make new measurements of ‘k’ (W/m.K) of porcine PV, esophagus, and phrenic nerve, all needed for PV cryoabalation treatment planning. Further, by modifying the sensor use from traditional to dynamic mode new measurements related to tissue vs. fluid (i.e. water) contact, fluid flow conditions, tissue thickness, and phase change were made. In summary, the in vitro idealized system data presented is promising and warrants future work to integrate and test supported “3ω” sensors on in vivo deployed focal therapy probe surfaces (i.e. balloons or catheters).

Study on the dose distribution of the mixed field with thermal and epi-thermal neutrons for neutron capture therapy

International Nuclear Information System (INIS)

Kobayashi, Tooru; Sakurai, Yoshinori; Kanda, Keiji

1994-01-01

Simulation calculations using DOT 3.5 were carried out in order to confirm the characteristics of depth-dependent dose distribution in water phantom dependent on incident neutron energy. The epithermal neutrons mixed to thermal neutron field is effective improving the thermal neutron depth-dose distribution for neutron capture therapy. A feasibility study on the neutron energy spectrum shifter was performed using ANISN-JR for the KUR Heavy Water Facility. The design of the neutron spectrum shifter is feasible, without reducing the performance as a thermal neutron irradiation field. (author)

Design Methodology of a Dual-Halbach Array Linear Actuator with Thermal-Electromagnetic Coupling.

Science.gov (United States)

Eckert, Paulo Roberto; Flores Filho, Aly Ferreira; Perondi, Eduardo; Ferri, Jeferson; Goltz, Evandro

2016-03-11

This paper proposes a design methodology for linear actuators, considering thermal and electromagnetic coupling with geometrical and temperature constraints, that maximizes force density and minimizes force ripple. The method allows defining an actuator for given specifications in a step-by-step way so that requirements are met and the temperature within the device is maintained under or equal to its maximum allowed for continuous operation. According to the proposed method, the electromagnetic and thermal models are built with quasi-static parametric finite element models. The methodology was successfully applied to the design of a linear cylindrical actuator with a dual quasi-Halbach array of permanent magnets and a moving-coil. The actuator can produce an axial force of 120 N and a stroke of 80 mm. The paper also presents a comparative analysis between results obtained considering only an electromagnetic model and the thermal-electromagnetic coupled model. This comparison shows that the final designs for both cases differ significantly, especially regarding its active volume and its electrical and magnetic loading. Although in this paper the methodology was employed to design a specific actuator, its structure can be used to design a wide range of linear devices if the parametric models are adjusted for each particular actuator.

Thermal expansion behavior study of Co nanowire array with in situ x-ray diffraction and x-ray absorption fine structure techniques

Science.gov (United States)

Mo, Guang; Cai, Quan; Jiang, Longsheng; Wang, Wei; Zhang, Kunhao; Cheng, Weidong; Xing, Xueqing; Chen, Zhongjun; Wu, Zhonghua

2008-10-01

In situ x-ray diffraction and x-ray absorption fine structure techniques were used to study the structural change of ordered Co nanowire array with temperature. The results show that the Co nanowires are polycrystalline with hexagonal close packed structure without phase change up until 700 °C. A nonlinear thermal expansion behavior has been found and can be well described by a quadratic equation with the first-order thermal expansion coefficient of 4.3×10-6/°C and the second-order thermal expansion coefficient of 5.9×10-9/°C. The mechanism of this nonlinear thermal expansion behavior is discussed.

Radon dynamics in underwater thermal radon therapy

International Nuclear Information System (INIS)

Lettner, H.; Hofmann, W.; Winkler, R.; Rolle, R.; Foisner, W.

1998-01-01

At a facility for underwater thermal radon therapy in Bad Hofgastein, experiments were carried out with the aim of establishing radon in the air exhaled by the treated patients and of radon decay products on the skin of the patients. The time course of radon concentration in the exhaled air shows a maximum a few minutes after entering the bath, then the Rn concentration remains constant over the remaining time spent in the bath. Taking into account several simplifying assumptions, the average dose to the epidermis from radon daughters is about 50 μGy. (A.K.)

The Surface Interface Characteristics of Vertically Aligned Carbon Nanotube and Graphitic Carbon Fiber Arrays Grown by Thermal and Plasma Enhanced Chemical Vapor Deposition

Science.gov (United States)

Delzeit, Lance; Nguyen, Cattien; Li, Jun; Han, Jie; Meyyappan, M.

2002-01-01

The development of nano-arrays for sensors and devices requires the growth of arrays with the proper characteristics. One such application is the growth of vertically aligned carbon nanotubes (CNTs) and graphitic carbon fibers (GCFs) for the chemical attachment of probe molecules. The effectiveness of such an array is dependent not only upon the effectiveness of the probe and the interface between that probe and the array, but also the array and the underlaying substrate. If that array is a growth of vertically aligned CNTs or GCFs then the attachment of that array to the surface is of the utmost importance. This attachment provides the mechanical stability and durability of the array, as well as, the electrical properties of that array. If the detection is to be acquired through an electrical measurement, then the appropriate resistance between the array and the surface need to be fabricated into the device. I will present data on CNTs and GCFs grown from both thermal and plasma enhanced chemical vapor deposition. The focus will be on the characteristics of the metal film from which the CNTs and GCFs are grown and the changes that occur due to changes within the growth process.

Silicon monolithic microchannel-cooled laser diode array

International Nuclear Information System (INIS)

Skidmore, J. A.; Freitas, B. L.; Crawford, J.; Satariano, J.; Utterback, E.; DiMercurio, L.; Cutter, K.; Sutton, S.

2000-01-01

A monolithic microchannel-cooled laser diode array is demonstrated that allows multiple diode-bar mounting with negligible thermal cross talk. The heat sink comprises two main components: a wet-etched Si layer that is anodically bonded to a machined glass block. The continuous wave (cw) thermal resistance of the 10 bar diode array is 0.032 degree sign C/W, which matches the performance of discrete microchannel-cooled arrays. Up to 1.5 kW/cm 2 is achieved cw at an emission wavelength of ∼808 nm. Collimation of a diode array using a monolithic lens frame produced a 7.5 mrad divergence angle by a single active alignment. This diode array offers high average power/brightness in a simple, rugged, scalable architecture that is suitable for large two-dimensional areas. (c) 2000 American Institute of Physics

Heat transfer due to electroconvulsive therapy: Influence of anisotropic thermal and electrical skull conductivity.

Science.gov (United States)

Menezes de Oliveira, Marilia; Wen, Peng; Ahfock, Tony

2016-09-01

This paper focuses on electroconvulsive therapy (ECT) and head models to investigate temperature profiles arising when anisotropic thermal and electrical conductivities are considered in the skull layer. The aim was to numerically investigate the threshold for which this therapy operates safely to the brain, from the thermal point of view. A six-layer spherical head model consisting of scalp, fat, skull, cerebro-spinal fluid, grey matter and white matter was developed. Later on, a realistic human head model was also implemented. These models were built up using the packages from COMSOL Inc. and Simpleware Ltd. In these models, three of the most common electrode montages used in ECT were applied. Anisotropic conductivities were derived using volume constraint and included in both spherical and realistic head models. The bio-heat transferring problem governed by Laplace equation was solved numerically. The results show that both the tensor eigenvalues of electrical conductivity and the electrode montage affect the maximum temperature, but thermal anisotropy does not have a significant influence. Temperature increases occur mainly in the scalp and fat, and no harm is caused to the brain by the current applied during ECT. The work assures the thermal safety of ECT and also provides a numerical method to investigate other non-invasive therapies. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Performance analysis of solar cell arrays in concentrating light intensity

International Nuclear Information System (INIS)

Xu Yongfeng; Li Ming; Lin Wenxian; Wang Liuling; Xiang Ming; Zhang Xinghua; Wang Yunfeng; Wei Shengxian

2009-01-01

Performance of concentrating photovoltaic/thermal system is researched by experiment and simulation calculation. The results show that the I-V curve of the GaAs cell array is better than that of crystal silicon solar cell arrays and the exergy produced by 9.51% electrical efficiency of the GaAs solar cell array can reach 68.93% of the photovoltaic/thermal system. So improving the efficiency of solar cell arrays can introduce more exergy and the system value can be upgraded. At the same time, affecting factors of solar cell arrays such as series resistance, temperature and solar irradiance also have been analyzed. The output performance of a solar cell array with lower series resistance is better and the working temperature has a negative impact on the voltage in concentrating light intensity. The output power has a -20 W/V coefficient and so cooling fluid must be used. Both heat energy and electrical power are then obtained with a solar trough concentrating photovoltaic/thermal system. (semiconductor devices)

Test stand for non-uniformity correction of microbolometer focal plane arrays used in thermal cameras

Science.gov (United States)

Krupiński, Michał; Bareła, Jaroslaw; Firmanty, Krzysztof; Kastek, Mariusz

2013-10-01

Uneven response of particular detectors (pixels) to the same incident power of infrared radiation is an inherent feature of microbolometer focal plane arrays. As a result an image degradation occurs, known as Fixed Pattern Noise (FPN), which distorts the thermal representation of an observed scene and impairs the parameters of a thermal camera. In order to compensate such non-uniformity, several NUC correction methods are applied in digital data processing modules implemented in thermal cameras. Coefficients required to perform the non-uniformity correction procedure (NUC coefficients) are determined by calibrating the camera against uniform radiation sources (blackbodies). Non-uniformity correction is performed in a digital processing unit in order to remove FPN pattern in the registered thermal images. Relevant correction coefficients are calculated on the basis of recorded detector responses to several values of radiant flux emitted from reference IR radiation sources (blackbodies). The measurement of correction coefficients requires specialized setup, in which uniform, extended radiation sources with high temperature stability are one of key elements. Measurement stand for NUC correction developed in Institute of Optoelectronics, MUT, comprises two integrated extended blackbodies with the following specifications: area 200×200 mm, stabilized absolute temperature range +15 °C÷100 °C, and uniformity of temperature distribution across entire surface +/-0.014 °C. Test stand, method used for the measurement of NUC coefficients and the results obtained during the measurements conducted on a prototype thermal camera will be presented in the paper.

Blood leakage detection during dialysis therapy based on fog computing with array photocell sensors and heteroassociative memory model.

Science.gov (United States)

Wu, Jian-Xing; Huang, Ping-Tzan; Lin, Chia-Hung; Li, Chien-Ming

2018-02-01

Blood leakage and blood loss are serious life-threatening complications occurring during dialysis therapy. These events have been of concerns to both healthcare givers and patients. More than 40% of adult blood volume can be lost in just a few minutes, resulting in morbidities and mortality. The authors intend to propose the design of a warning tool for the detection of blood leakage/blood loss during dialysis therapy based on fog computing with an array of photocell sensors and heteroassociative memory (HAM) model. Photocell sensors are arranged in an array on a flexible substrate to detect blood leakage via the resistance changes with illumination in the visible spectrum of 500-700 nm. The HAM model is implemented to design a virtual alarm unit using electricity changes in an embedded system. The proposed warning tool can indicate the risk level in both end-sensing units and remote monitor devices via a wireless network and fog/cloud computing. The animal experimental results (pig blood) will demonstrate the feasibility.

Multi-parameter fibre Bragg grating sensor-array for thermal vacuum cycling test

Science.gov (United States)

Cheng, L.; Ahlers, B.; Toet, P.; Casarosa, G.; Appolloni, M.

2017-11-01

Fibre Bragg Grating (FBG) sensor systems based on optical fibres are gaining interest in space applications. Studies on Structural Health Monitoring (SHM) of the reusable launchers using FBG sensors have been carried out in the Future European Space Transportation Investigations Programme (FESTIP). Increasing investment in the development on FBG sensor applications is foreseen for the Future Launchers Preparatory Programme (FLPP). TNO has performed different SHM measurements with FBGs including on the VEGA interstage [1, 2] in 2006. Within the current project, a multi-parameter FBG sensor array demonstrator system for temperature and strain measurements is designed, fabricated and tested under ambient as well as Thermal Vacuum (TV) conditions in a TV chamber of the European Space Agency (ESA), ESTEC site. The aim is the development of a multi-parameters measuring system based on FBG technology for space applications. During the TV tests of a Space Craft (S/C) or its subsystems, thermal measurements, as well as strain measurements are needed by the engineers in order to verify their prediction and to validate their models. Because of the dimensions of the test specimen and the accuracy requested to the measurement, a large number of observation/measuring points are needed. Conventional sensor systems require a complex routing of the cables connecting the sensors to their acquisition unit. This will add extra weight to the construction under test. FBG sensors are potentially light-weight and can easily be multiplexed in an array configuration. The different tasks comply of a demonstrator system design; its component selection, procurement, manufacturing and finally its assembly. The temperature FBG sensor is calibrated in a dedicated laboratory setup down to liquid nitrogen (LN2) temperature at TNO. A temperature-wavelength calibration curve is generated. After a test programme definition a setup in thermal vacuum is realised at ESA premises including a mechanical

3D perfused brain phantom for interstitial ultrasound thermal therapy and imaging: design, construction and characterization

International Nuclear Information System (INIS)

Martínez, José M; Jarosz, Boguslaw J

2015-01-01

Thermal therapy has emerged as an independent modality of treating some tumors. In many clinics the hyperthermia, one of the thermal therapy modalities, has been used adjuvant to radio- or chemotherapy to substantially improve the clinical treatment outcomes. In this work, a methodology for building a realistic brain phantom for interstitial ultrasound low dose-rate thermal therapy of the brain is proposed. A 3D brain phantom made of the tissue mimicking material (TMM) had the acoustic and thermal properties in the 20–32 °C range, which is similar to that of a brain at 37 °C. The phantom had 10–11% by mass of bovine gelatin powder dissolved in ethylene glycol. The TMM sonicated at 1 MHz, 1.6 MHz and 2.5 MHz yielded the amplitude attenuation coefficients of 62  ±  1 dB m −1 , 115  ±  4 dB m −1 and 175  ±  9 dB m −1 , respectively. The density and acoustic speed determination at room temperature (∼24 °C) gave 1040  ±  40 kg m −3 and 1545  ±  44 m s −1 , respectively. The average thermal conductivity was 0.532 W m −1  K −1 . The T1 and T2 values of the TMM were 207  ±  4 and 36.2  ±  0.4 ms, respectively. We envisage the use of our phantom for treatment planning and for quality assurance in MRI based temperature determination. Our phantom preparation methodology may be readily extended to other thermal therapy technologies. (paper)

Elevation of antioxidant enzymes in the clinical effects of radon and thermal therapy for bronchial asthma

International Nuclear Information System (INIS)

Mitsunobu, Fumihiro; Hosaki, Yasuhiro; Ashida, Kozo; Tanizaki, Yoshiro; Yamaoka, Kiyonori; Hanamoto, Katsumi; Sugita, Katsuhiro; Kojima, Shuji

2003-01-01

An increased systemic production of oxygen-free radicals by activated inflammatory cells is thought to be involved in the pathophysiology of asthma. The aim of this study is to evaluate the clinical effects of radon and thermal therapy on asthma in relation to antioxidant enzymes and lipid peroxide. Radon and thermal therapy were performed once a week. All subjects went to a hot bathroom with a high concentration of radon, and nasal inhalation of vapor from a hot spring was performed for 40 min once a day under conditions of high humidity. The room temperature was 48 deg C; the room radon concentration was 2,080 Bq/m 3 . Blood samples were collected at 2 h, 14, and 28 days after the first therapy. A blood sample also was collected before the first therapy (at body temperature and background radon level) to be used as the control. The forced expiratory volume in one second (%FEV 1 ) was significantly increased 28 days after the first therapy. On day 28, the catalase (CAT) activity was significantly increased in comparison with the control. The superoxide dismutase (SOD) activity was significantly increased compared to the control after first inhalation. On days 14 and 28, the lipid peroxide level was significantly decreased in comparison with the control. In conclusion, the present pilot study has shown that radon and thermal therapy improved the pulmonary function of asthmatics by increasing the reduced activities of antioxidant enzymes. (author)

A study on the utilization of hyper-thermal neutrons for neutron capture therapy

International Nuclear Information System (INIS)

Sakurai, Yoshinori; Kobayashi, Tooru; Kanda, Keiji

1993-01-01

The utilization of hyper-thermal neutrons, which have an energy spectrum of a Maxwellian distribution of a higher temperature than the room temperature of 300 K, was studied in order to improve the thermal neutron flux distribution at the deeper part in a living body for neutron capture therapy. Simulation calculations were carried out using MCNP-V3 in order to confirm the characteristics of hyper-thermal neutrons, i.e., (1) depth dependence of neutron energy spectrum, and (2) depth distribution of the reaction rate in a water phantom for materials with 1/v neutron absorption. It is confirmed that the hyper-thermal neutron irradiation can improve the thermal neutron flux distribution in the deeper and wider area in a living body compared with the thermal neutron irradiation. Practically, by the incidence of the hyper-thermal neutrons with a 3000 K Maxwellian distribution, the thermal neutron flux at 5 cm depth can be given about four times larger than by the incidence of the thermal neutrons of 300 K. (author)

Nanofabrication and characterization of ZnO nanorod arrays and branched microrods by aqueous solution route and rapid thermal processing

International Nuclear Information System (INIS)

Lupan, Oleg; Chow, Lee; Chai, Guangyu; Roldan, Beatriz; Naitabdi, Ahmed; Schulte, Alfons; Heinrich, Helge

2007-01-01

This paper presents an inexpensive and fast fabrication method for one-dimensional (1D) ZnO nanorod arrays and branched two-dimensional (2D), three-dimensional (3D) - nanoarchitectures. Our synthesis technique includes the use of an aqueous solution route and post-growth rapid thermal annealing. It permits rapid and controlled growth of ZnO nanorod arrays of 1D - rods, 2D - crosses, and 3D - tetrapods without the use of templates or seeds. The obtained ZnO nanorods are uniformly distributed on the surface of Si substrates and individual or branched nano/microrods can be easily transferred to other substrates. Process parameters such as concentration, temperature and time, type of substrate and the reactor design are critical for the formation of nanorod arrays with thin diameter and transferable nanoarchitectures. X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, transmission electron microscopy and Micro-Raman spectroscopy have been used to characterize the samples

Blood leakage detection during dialysis therapy based on fog computing with array photocell sensors and heteroassociative memory model

Science.gov (United States)

Wu, Jian-Xing; Huang, Ping-Tzan; Li, Chien-Ming

2018-01-01

Blood leakage and blood loss are serious life-threatening complications occurring during dialysis therapy. These events have been of concerns to both healthcare givers and patients. More than 40% of adult blood volume can be lost in just a few minutes, resulting in morbidities and mortality. The authors intend to propose the design of a warning tool for the detection of blood leakage/blood loss during dialysis therapy based on fog computing with an array of photocell sensors and heteroassociative memory (HAM) model. Photocell sensors are arranged in an array on a flexible substrate to detect blood leakage via the resistance changes with illumination in the visible spectrum of 500–700 nm. The HAM model is implemented to design a virtual alarm unit using electricity changes in an embedded system. The proposed warning tool can indicate the risk level in both end-sensing units and remote monitor devices via a wireless network and fog/cloud computing. The animal experimental results (pig blood) will demonstrate the feasibility. PMID:29515815

Subsurface thermal behaviour of tissue mimics embedded with large blood vessels during plasmonic photo-thermal therapy.

Science.gov (United States)

Paul, Anup; Narasimhan, Arunn; Das, Sarit K; Sengupta, Soujit; Pradeep, Thalappil

2016-11-01

The purpose of this study was to understand the subsurface thermal behaviour of a tissue phantom embedded with large blood vessels (LBVs) when exposed to near-infrared (NIR) radiation. The effect of the addition of nanoparticles to irradiated tissue on the thermal sink behaviour of LBVs was also studied. Experiments were performed on a tissue phantom embedded with a simulated blood vessel of 2.2 mm outer diameter (OD)/1.6 mm inner diameter (ID) with a blood flow rate of 10 mL/min. Type I collagen from bovine tendon and agar gel were used as tissue. Two different nanoparticles, gold mesoflowers (AuMS) and graphene nanostructures, were synthesised and characterised. Energy equations incorporating a laser source term based on multiple scattering theories were solved using finite element-based commercial software. The rise in temperature upon NIR irradiation was seen to vary according to the position of the blood vessel and presence of nanoparticles. While the maximum rise in temperature was about 10 °C for bare tissue, it was 19 °C for tissue embedded with gold nanostructures and 38 °C for graphene-embedded tissues. The axial temperature distribution predicted by computational simulation matched the experimental observations. A different subsurface temperature distribution has been obtained for different tissue vascular network models. The position of LBVs must be known in order to achieve optimal tissue necrosis. The simulation described here helps in predicting subsurface temperature distributions within tissues during plasmonic photo-thermal therapy so that the risks of damage and complications associated with in vivo experiments and therapy may be avoided.

WE-H-209-01: Advances in Ultrasound Therapy

Energy Technology Data Exchange (ETDEWEB)

Hynynen, K. [University of Toronto (Canada)

2016-06-15

Focused ultrasound has been shown to be the only method that allows noninvasive thermal coagulation of tissues and recently this potential has been explored for image-guided drug delivery. In this presentation, the advances in ultrasound phased array technology for energy delivery, exposure monitoring and control will be discussed. Experimental results from novel multi-frequency transmit/receive arrays will be presented. In addition, the feasibility of fully electronically focused and steered high power arrays with many thousands of transducer elements will be discussed. Finally, some of the recent clinical and preclinical results for the treatment of brain disease will be reviewed. Learning Objectives: Introduce FUS therapy principles and modern techniques Discuss use of FUS for drug delivery Cover the technology required to deliver FUS and monitor therapy Present clinical examples of the uses of these techniques This research was supported by funding from The Canada Research Chair Program, Grants from CIHR and NIH (no. EB003268).; K. Hynynen, Canada Foundation for Innovation; Canadian Institutes of Health Research; Focused Ultrasound Surgery Foundation; Canada Research Chair Program; Natural Sciences and Engineering Research Council of Canada; Ontario Research Fund; National Institutes of Health; Canadian Cancer Society Research Institute; The Weston Brain Institute; Harmonic Medical; Focused Ultrasound Instruments.

WE-H-209-01: Advances in Ultrasound Therapy

International Nuclear Information System (INIS)

Hynynen, K.

2016-01-01

Focused ultrasound has been shown to be the only method that allows noninvasive thermal coagulation of tissues and recently this potential has been explored for image-guided drug delivery. In this presentation, the advances in ultrasound phased array technology for energy delivery, exposure monitoring and control will be discussed. Experimental results from novel multi-frequency transmit/receive arrays will be presented. In addition, the feasibility of fully electronically focused and steered high power arrays with many thousands of transducer elements will be discussed. Finally, some of the recent clinical and preclinical results for the treatment of brain disease will be reviewed. Learning Objectives: Introduce FUS therapy principles and modern techniques Discuss use of FUS for drug delivery Cover the technology required to deliver FUS and monitor therapy Present clinical examples of the uses of these techniques This research was supported by funding from The Canada Research Chair Program, Grants from CIHR and NIH (no. EB003268).; K. Hynynen, Canada Foundation for Innovation; Canadian Institutes of Health Research; Focused Ultrasound Surgery Foundation; Canada Research Chair Program; Natural Sciences and Engineering Research Council of Canada; Ontario Research Fund; National Institutes of Health; Canadian Cancer Society Research Institute; The Weston Brain Institute; Harmonic Medical; Focused Ultrasound Instruments

Thermal-to-visible transducer (TVT) for thermal-IR imaging

Science.gov (United States)

Flusberg, Allen; Swartz, Stephen; Huff, Michael; Gross, Steven

2008-04-01

We have been developing a novel thermal-to-visible transducer (TVT), an uncooled thermal-IR imager that is based on a Fabry-Perot Interferometer (FPI). The FPI-based IR imager can convert a thermal-IR image to a video electronic image. IR radiation that is emitted by an object in the scene is imaged onto an IR-absorbing material that is located within an FPI. Temperature variations generated by the spatial variations in the IR image intensity cause variations in optical thickness, modulating the reflectivity seen by a probe laser beam. The reflected probe is imaged onto a visible array, producing a visible image of the IR scene. This technology can provide low-cost IR cameras with excellent sensitivity, low power consumption, and the potential for self-registered fusion of thermal-IR and visible images. We will describe characteristics of requisite pixelated arrays that we have fabricated.

Thermal-hydraulic performance of a multiple jet cooling module with a concave dimple array in a helium-cooled divertor

Energy Technology Data Exchange (ETDEWEB)

Jung, Hyo-Yeon; Kim, Kwang-Yong, E-mail: kykim@inha.ac.kr

2017-01-15

A numerical study was performed to evaluate the thermal-hydraulic performance of a finger type cooling module, where multiple jets impinge on the surface with concave dimples, in the divertor of a nuclear fusion reactor. Conjugate heat transfer was analyzed in both the solid and fluid domains using three-dimensional Reynolds-averaged Navier-Stokes equations with the shear stress transport turbulence model. The computational domain consisted of a single fluid domain and three solid domains: tile, thimble, and cartridge. The numerical results for the temperature variation on the tile were validated in comparison with the experimental data. A parametric study was performed with two design variables, the ratios of dimple diameter and dimple height to the nozzle diameter, and two dimple arrays (inline and staggered arrays). The parametric study showed that the heat transfer rate was increased by up to 2.62% by introducing concave dimples, and that the heat transfer and pressure drop performances increased with increasing diameter and height of the dimples for a specified dimple array.

Development of a quantum dot mediated thermometry for minimally invasive thermal therapy

Science.gov (United States)

Hanson, Willard L.

Thermally-related, minimally invasive therapies are designed to treat tumors while minimizing damage to the surrounding tissues. Adjacent tissues become susceptible to thermal injury to ensure the cancer is completely destroyed. Destroying tumor cells, while minimizing collateral damage to the surrounding tissue, requires the capacity to control and monitor tissue temperatures both spatially and temporally. Current devices measure the tumor's tissue temperature at a specific location leaving the majority unmonitored. A point-wise application can not substantiate complete tumor destruction. This type of surgery would be more effective if volumetric tissue temperature measurement were available. On this premise, the feasibility of a quantum dot (QD) assembly to measure the tissue temperature volumetrically was tested in the experiments described in this dissertation. QDs are fluorescence semiconductor nanoparticles having various superior optical properties. This new QD-mediated thermometry is capable of monitoring the thermal features of tissues non-invasively by measuring the aggregate fluorescence intensity of the QDs accumulated at the target tissues prior to and during the surgical procedure. Thus, such a modality would allow evaluation of tissue destruction by measuring the fluorescence intensity of the QD as a function of temperature. The present study also quantified the photoluminescence intensity and attenuation of the QD as a function of depth and wavelength using a tissue phantom. A prototype system was developed to measure the illumination through a tissue phantom as a proof of concept of the feasibility of a noninvasive thermal therapy. This prototype includes experimental hardware, software and working methods to perform image acquisition, and data reduction strategic to quantify the intensity and transport characteristics of the QD. The significance of this work is that real-time volumetric temperature information will prove a more robust tool for use

Kalman Filtered MR Temperature Imaging for Laser Induced Thermal Therapies

OpenAIRE

Fuentes, D.; Yung, J.; Hazle, J. D.; Weinberg, J. S.; Stafford, R. J.

2011-01-01

The feasibility of using a stochastic form of Pennes bioheat model within a 3D finite element based Kalman filter (KF) algorithm is critically evaluated for the ability to provide temperature field estimates in the event of magnetic resonance temperature imaging (MRTI) data loss during laser induced thermal therapy (LITT). The ability to recover missing MRTI data was analyzed by systematically removing spatiotemporal information from a clinical MR-guided LITT procedure in human brain and comp...

Flat-plate photovoltaic array design optimization

Science.gov (United States)

Ross, R. G., Jr.

1980-01-01

An analysis is presented which integrates the results of specific studies in the areas of photovoltaic structural design optimization, optimization of array series/parallel circuit design, thermal design optimization, and optimization of environmental protection features. The analysis is based on minimizing the total photovoltaic system life-cycle energy cost including repair and replacement of failed cells and modules. This approach is shown to be a useful technique for array optimization, particularly when time-dependent parameters such as array degradation and maintenance are involved.

Thermal efficiency of Duovent array glassing; Eficiencia termica de arreglos de vidrios Duovent

Energy Technology Data Exchange (ETDEWEB)

Alvarez Garcia G; Cortina Leyva, C; Flores Prieto, Jose J [Centro Nacional de Investigacion y Tecnologico, DGIT SEP, Cuernavaca, Morelos (Mexico)

2000-07-01

This paper presents an experimental study of the thermal performance of duovent glazing with different solar control coatings. The thermal efficiency, {eta}, was determined. The duovent array consists of 6 mm glass+solar coating+air layer+6 mm glass. The width of the air layer between the two glasses is 12 mm. The experimental work was carried out using a calorimeter setup calling DEMETEV. The DEMETEV was specially designed to measure the heat gains through sample glassings. The heat flux, the shading coefficients and the thermal efficiency curve as a function of the temperature difference and incident radiative flux are presented. Comparing the results for duovent with clear glasses with the ones reported by Dubrous show a difference of 2.2%. Also this study verifies the theoretical model reported. [Spanish] En este trabajo se presenta un estudio experimental del comportamiento termico de vidrios Duovent con diferentes filtros solares mediante el calculo de la eficiencia termica, {eta}. El arreglo lo comprende vidrio+filtro+aire+vidrio de 6 mm de espesor con un espacio con aire entre vidrios de 12 mm. El trabajo experimental se llevo a cabo haciendo uso del dispositivo calorimetrico experimental, denominado DEMETEV, que fue disenado especialmente para medir las ganancias de calor a traves de vidrios. Se presentan los flujos de calor, los coeficientes de sombreado y la curva de eficiencia termica como funcion de la diferencia de temperaturas y del flujo radioactivo incidente. Los resultados obtenidos para vidrios claros fueron comparados con los que se obtuvieron en el trabajo reportado por Dubrous obteniendo una diferencia del 2.2%. Tambien se presenta la validacion de los datos experimentales con un modelo teorico reportado.

Gold Nanoparticles as a Photothermal Agent in Cancer Therapy: The Thermal Ablation Characteristic Length

Directory of Open Access Journals (Sweden)

Thomas Grosges

2018-05-01

Full Text Available In cancer therapy, the thermal ablation of diseased cells by embedded nanoparticles is one of the known therapies. It is based on the absorption of the energy of the illuminating laser by nanoparticles. The resulting heating of nanoparticles kills the cell where these photothermal agents are embedded. One of the main constraints of this therapy is preserving the surrounding healthy cells. Therefore, two parameters are of interest. The first one is the thermal ablation characteristic length, which corresponds to an action distance around the nanoparticles for which the temperature exceeds the ablation threshold. This critical geometric parameter is related to the expected conservation of the body temperature in the surroundings of the diseased cell. The second parameter is the temperature that should be reached to achieve active thermal agents. The temperature depends on the power of the illuminating laser, on the size of nanoparticles and on their physical properties. The purpose of this paper is to propose behavior laws under the constraints of both the body temperature at the boundary of the cell to preserve surrounding cells and an acceptable range of temperature in the target cell. The behavior laws are deduced from the finite element method, which is able to model aggregates of nanoparticles. We deduce sensitivities to the laser power and to the particle size. We show that the tuning of the temperature elevation and of the distance of action of a single nanoparticle is not significantly affected by variations of the particle size and of the laser power. Aggregates of nanoparticles are much more efficient, but represent a potential risk to the surrounding cells. Fortunately, by tuning the laser power, the thermal ablation characteristic length can be controlled.

Hyperbaric oxygen therapy attenuates central sensitization induced by a thermal injury in humans

DEFF Research Database (Denmark)

Rasmussen, V M; Borgen, A E; Jansen, E C

2015-01-01

BACKGROUND: Hyperbaric oxygen (HBO2 ) treatment has in animal experiments demonstrated antinociceptive effects. It was hypothesized that these effects would attenuate secondary hyperalgesia areas (SHAs), an expression of central sensitization, after a first-degree thermal injury in humans. METHODS...... was demonstrated. However, in the nine volunteers starting with the control session, a statistical significant attenuation of SHAs was demonstrated in the HBO2 session (P = 0.004). CONCLUSIONS: The results indicate that HBO2 therapy in humans attenuates central sensitization induced by a thermal skin injury......, compared with control. These new and original findings in humans corroborate animal experimental data. The thermal injury model may give impetus to future human neurophysiological studies exploring the central effects of hyperbaric oxygen treatment....

Hot Spots Detection of Operating PV Arrays through IR Thermal Image Using Method Based on Curve Fitting of Gray Histogram

Directory of Open Access Journals (Sweden)

Jiang Lin

2016-01-01

Full Text Available The overall efficiency of PV arrays is affected by hot spots which should be detected and diagnosed by applying responsible monitoring techniques. The method using the IR thermal image to detect hot spots has been studied as a direct, noncontact, nondestructive technique. However, IR thermal images suffer from relatively high stochastic noise and non-uniformity clutter, so the conventional methods of image processing are not effective. The paper proposes a method to detect hotspots based on curve fitting of gray histogram. The result of MATLAB simulation proves the method proposed in the paper is effective to detect the hot spots suppressing the noise generated during the process of image acquisition.

Polarization measurements made on LFRA and OASIS emitter arrays

Science.gov (United States)

Geske, Jon; Sparkman, Kevin; Oleson, Jim; Laveigne, Joe; Sieglinger, Breck; Marlow, Steve; Lowry, Heard; Burns, James

2008-04-01

Polarization is increasingly being considered as a method of discrimination in passive sensing applications. In this paper the degree of polarization of the thermal emission from the emitter arrays of two new Santa Barbara Infrared (SBIR) micro-bolometer resistor array scene projectors was characterized at ambient temperature and at 77 K. The emitter arrays characterized were from the Large Format Resistive Array (LFRA) and the Optimized Arrays for Space-Background Infrared Simulation (OASIS) scene projectors. This paper reports the results of this testing.

Fiber-array based optogenetic prosthetic system for stimulation therapy

Science.gov (United States)

Gu, Ling; Cote, Chris; Tejeda, Hector; Mohanty, Samarendra

2012-02-01

Recent advent of optogenetics has enabled activation of genetically-targeted neuronal cells using low intensity blue light with high temporal precision. Since blue light is attenuated rapidly due to scattering and absorption in neural tissue, optogenetic treatment of neurological disorders may require stimulation of specific cell types in multiple regions of the brain. Further, restoration of certain neural functions (vision, and auditory etc) requires accurate spatio-temporal stimulation patterns rather than just precise temporal stimulation. In order to activate multiple regions of the central nervous system in 3D, here, we report development of an optogenetic prosthetic comprising of array of fibers coupled to independently-controllable LEDs. This design avoids direct contact of LEDs with the brain tissue and thus does not require electrical and heat isolation, which can non-specifically stimulate and damage the local brain regions. The intensity, frequency, and duty cycle of light pulses from each fiber in the array was controlled independently using an inhouse developed LabView based program interfaced with a microcontroller driving the individual LEDs. While the temporal profile of the light pulses was controlled by varying the current driving the LED, the beam profile emanating from each fiber tip could be sculpted by microfabrication of the fiber tip. The fiber array was used to stimulate neurons, expressing channelrhodopsin-2, in different locations within the brain or retina. Control of neural activity in the mice cortex, using the fiber-array based prosthetic, is evaluated from recordings made with multi-electrode array (MEA). We also report construction of a μLED array based prosthetic for spatio-temporal stimulation of cortex.

Kalman filtered MR temperature imaging for laser induced thermal therapies.

Science.gov (United States)

Fuentes, D; Yung, J; Hazle, J D; Weinberg, J S; Stafford, R J

2012-04-01

The feasibility of using a stochastic form of Pennes bioheat model within a 3-D finite element based Kalman filter (KF) algorithm is critically evaluated for the ability to provide temperature field estimates in the event of magnetic resonance temperature imaging (MRTI) data loss during laser induced thermal therapy (LITT). The ability to recover missing MRTI data was analyzed by systematically removing spatiotemporal information from a clinical MR-guided LITT procedure in human brain and comparing predictions in these regions to the original measurements. Performance was quantitatively evaluated in terms of a dimensionless L(2) (RMS) norm of the temperature error weighted by acquisition uncertainty. During periods of no data corruption, observed error histories demonstrate that the Kalman algorithm does not alter the high quality temperature measurement provided by MR thermal imaging. The KF-MRTI implementation considered is seen to predict the bioheat transfer with RMS error 10 sec.

Daytime Solar Heating of Photovoltaic Arrays in Low Density Plasmas

Science.gov (United States)

Galofaro, J.; Vayner, B.; Ferguson, D.

2003-01-01

The purpose of the current work is to determine the out-gassing rate of H2O molecules for a solar array placed under daytime solar heating (full sunlight) conditions typically encountered in a Low Earth Orbital (LEO) environment. Arc rates are established for individual arrays held at 14 C and are used as a baseline for future comparisons. Radiated thermal solar flux incident to the array is simulated by mounting a stainless steel panel equipped with resistive heating elements several centimeters behind the array. A thermal plot of the heater plate temperature and the array temperature as a function of heating time is then obtained. A mass spectrometer is used to record the levels of partial pressure of water vapor in the test chamber after each of the 5 heating/cooling cycles. Each of the heating cycles was set to time duration of 40 minutes to simulate the daytime solar heat flux to the array over a single orbit. Finally the array is cooled back to ambient temperature after 5 complete cycles and the arc rates of the solar arrays is retested. A comparison of the various data is presented with rather some unexpected results.

First detection of thermal radio emission from solar-type stars with the Karl G. Jansky very large array

Energy Technology Data Exchange (ETDEWEB)

Villadsen, Jackie; Hallinan, Gregg; Bourke, Stephen [Department of Astronomy, California Institute of Technology, 1200 E. California Ave., Pasadena, CA 91125 (United States); Güdel, Manuel [Department of Astrophysics, University of Vienna, Türkenschanzstrasse 17, A-1180 Vienna (Austria); Rupen, Michael, E-mail: jrv@astro.caltech.edu [National Radio Astronomy Observatory, Socorro, NM 87801 (United States)

2014-06-20

We present the first detections of thermal radio emission from the atmospheres of solar-type stars τ Cet, η Cas A, and 40 Eri A. These stars all resemble the Sun in age and level of magnetic activity, as indicated by X-ray luminosity and chromospheric emission in Ca II H and K lines. We observed these stars with the Karl G. Jansky Very Large Array with sensitivities of a few μJy at combinations of 10.0, 15.0, and 34.5 GHz. τ Cet, η Cas A, and 40 Eri A are all detected at 34.5 GHz with signal-to-noise ratios of 6.5, 5.2, and 4.5, respectively. 15.0 GHz upper limits imply a rising spectral index greater than 1.0 for τ Cet and 1.6 for η Cas A, at the 95% confidence level. The measured 34.5 GHz flux densities correspond to stellar disk-averaged brightness temperatures of roughly 10,000 K, similar to the solar brightness temperature at the same frequency. We explain this emission as optically thick thermal free-free emission from the chromosphere, with possible contributions from coronal gyroresonance emission above active regions and coronal free-free emission. These and similar quality data on other nearby solar-type stars, when combined with Atacama Large Millimeter/Submillimeter Array observations, will enable the construction of temperature profiles of their chromospheres and lower transition regions.

First detection of thermal radio emission from solar-type stars with the Karl G. Jansky very large array

International Nuclear Information System (INIS)

Villadsen, Jackie; Hallinan, Gregg; Bourke, Stephen; Güdel, Manuel; Rupen, Michael

2014-01-01

We present the first detections of thermal radio emission from the atmospheres of solar-type stars τ Cet, η Cas A, and 40 Eri A. These stars all resemble the Sun in age and level of magnetic activity, as indicated by X-ray luminosity and chromospheric emission in Ca II H and K lines. We observed these stars with the Karl G. Jansky Very Large Array with sensitivities of a few μJy at combinations of 10.0, 15.0, and 34.5 GHz. τ Cet, η Cas A, and 40 Eri A are all detected at 34.5 GHz with signal-to-noise ratios of 6.5, 5.2, and 4.5, respectively. 15.0 GHz upper limits imply a rising spectral index greater than 1.0 for τ Cet and 1.6 for η Cas A, at the 95% confidence level. The measured 34.5 GHz flux densities correspond to stellar disk-averaged brightness temperatures of roughly 10,000 K, similar to the solar brightness temperature at the same frequency. We explain this emission as optically thick thermal free-free emission from the chromosphere, with possible contributions from coronal gyroresonance emission above active regions and coronal free-free emission. These and similar quality data on other nearby solar-type stars, when combined with Atacama Large Millimeter/Submillimeter Array observations, will enable the construction of temperature profiles of their chromospheres and lower transition regions.

The performance analysis of the Trough Concentrating Solar Photovoltaic/Thermal system

Energy Technology Data Exchange (ETDEWEB)

Li, M., E-mail: liming@ynnu.edu.c [Solar Energy Research Institute, Yunnan Normal University, 650092 Kunming (China); Li, G.L. [School of Physics and Electronic Information, Yunnan Normal University, Kunming 650092 (China); Ji, X.; Yin, F.; Xu, L. [Solar Energy Research Institute, Yunnan Normal University, 650092 Kunming (China)

2011-06-15

Research highlights: {yields} A 2 m{sup 2} Trough Concentrating Photovoltaic/Thermal (TCPV/T) system is built, a single crystalline silicon solar cell array, a polycrystalline silicon cell array, a Super cell array and a GaAs cell array are respectively used in the experiments. {yields} Another 10 m{sup 2} TCPV/T system using the GaAs cell array and a concentrating silicon cell array are also constructed and characterized. {yields} The economic performance analysis show the electricity generating cost of the TCPV/T system with the concentrating silicon cell array can catch up with flat-plate PV system. -- Abstract: The electrical and thermal performance of a 2 m{sup 2} Trough Concentrating Photovoltaic/Thermal (TCPV/T) system with an energy flux ratio 10.27 are characterized by experiments. A single crystalline silicon solar cell array, a polycrystalline silicon cell array, a Super cell array and a GaAs cell array are respectively used in the experiments. The experimental results show that the electrical performance of the system with the GaAs cell array is better than that of crystal silicon solar cell arrays. The superior output performance of the GaAs cell array mainly benefits from its lower series resistance. But the thermal performances of the system using the single crystal silicon solar cell array and the polycrystalline silicon solar cell array are better. It results from the widths of the two types of cells in the system close to that of the focal line. Another 10 m{sup 2} TCPV/T system with an energy flux ratio of 20 using the GaAs cell array and a concentrating silicon cell array are also constructed and characterized. The experimental results indicate that the photoelectric efficiency of the GaAs cell array is 23.83%, and the instantaneous electrical efficiency and thermal efficiency of the system are 9.88% and 49.84% respectively. While the instantaneous electrical efficiency and thermal efficiency of the system using the low-cost concentrating

The performance analysis of the Trough Concentrating Solar Photovoltaic/Thermal system

International Nuclear Information System (INIS)

Li, M.; Li, G.L.; Ji, X.; Yin, F.; Xu, L.

2011-01-01

Research highlights: → A 2 m 2 Trough Concentrating Photovoltaic/Thermal (TCPV/T) system is built, a single crystalline silicon solar cell array, a polycrystalline silicon cell array, a Super cell array and a GaAs cell array are respectively used in the experiments. → Another 10 m 2 TCPV/T system using the GaAs cell array and a concentrating silicon cell array are also constructed and characterized. → The economic performance analysis show the electricity generating cost of the TCPV/T system with the concentrating silicon cell array can catch up with flat-plate PV system. -- Abstract: The electrical and thermal performance of a 2 m 2 Trough Concentrating Photovoltaic/Thermal (TCPV/T) system with an energy flux ratio 10.27 are characterized by experiments. A single crystalline silicon solar cell array, a polycrystalline silicon cell array, a Super cell array and a GaAs cell array are respectively used in the experiments. The experimental results show that the electrical performance of the system with the GaAs cell array is better than that of crystal silicon solar cell arrays. The superior output performance of the GaAs cell array mainly benefits from its lower series resistance. But the thermal performances of the system using the single crystal silicon solar cell array and the polycrystalline silicon solar cell array are better. It results from the widths of the two types of cells in the system close to that of the focal line. Another 10 m 2 TCPV/T system with an energy flux ratio of 20 using the GaAs cell array and a concentrating silicon cell array are also constructed and characterized. The experimental results indicate that the photoelectric efficiency of the GaAs cell array is 23.83%, and the instantaneous electrical efficiency and thermal efficiency of the system are 9.88% and 49.84% respectively. While the instantaneous electrical efficiency and thermal efficiency of the system using the low-cost concentrating silicon cell array are 7.51% and 42

Theoretical thermal dosimetry produced by an annular phased array system in CT-based patient models

International Nuclear Information System (INIS)

Paulsen, K.D.; Strohbehn, J.W.; Lynch, D.R.

1984-01-01

Theoretical calculations for the specific absorption rate (SAR) and the resulting temperature distributions produced by an annular phased array (APA) type system are made. The finite element numerical method is used in the formulation of both the electromagnetic (EM) and the thermal boundary value problems. A number of detailed patient models based on CT-scan data from the pelvic, visceral, and thoracic regions are generated to stimulate a variety of tumor locations and surrounding normal tissues. The SAR values from the EM solution are input into the bioheat transfer equation, and steady-rate temperature distributions are calculated for a wide variety of blood flow rates. Based on theoretical modeling, the APA shows no preferential heating of superficial over deep-seated tumors. However, in most cases satisfactory thermal profiles (therapeutic volume near 60%) are obtained in all three regions of the human trunk only for tumors with little or no blood flow. Unsatisfactory temperature patterns (therapeutic volume <50%) are found for tumors with moderate to high perfusion rates. These theoretical calculations should aid the clinician in the evaluation of the effectiveness of APA type devices in heating tumors located in the trunk region

In vitro assessment of the efficacy of thermal therapy in human benign prostatic hyperplasia

NARCIS (Netherlands)

Bhowmick, P.; Coad, J. E.; Bhowmick, S.; Pryor, J. L.; Larson, T.; de la Rosette, J.; Bischof, J. C.

2004-01-01

The successful management of BPH with minimally invasive thermal therapies requires a firm understanding of the temperature-time relationship for tissue destruction. In order to accomplish this objective, the present in vitro study assesses the cellular viability of human BPH tissue subjected to an

Development of FIR arrays with integrating amplifiers

Science.gov (United States)

Young, Erick T.

1988-08-01

The development of optimized photoconductor arrays suitable for far infrared space astronomical applications are described. Although the primary impetus is the production of a 16 by 16 element Ge:Ga demonstration array for SIRTF, the extension of this technology to Large Deployable Reflector (LDR) is considered. The optimization of Ge:Ga and Ge:Be photoconductor materials is discussed. In collaboration with Lawrence Berkeley Laboratory, measurements of FIR photoconductors with quantum efficiencies greater than 20 percent at 100 micrometers, and dark currents below 300 electrons/s are presented. Integrating J-FET amplifier technology is discussed. The current generation of integrating amplifiers has a demonstrated read noise of less than 20 electrons for an integration time of 100 s. The design is shown for a stackable 16 x n Ge:Ga array that utilizes a 16-channel monolithic version of the J-FET integrator. A part of the design is the use of a thin, thermally insulating substrate that allows the electronics to operate at the optimum temperature of 50 K while maintaining thermal and optical isolation from the detectors at 2 K. The power dissipation for the array is less than 16 mW. The array design may particularly be applicable to high resolution imaging spectrometers for LDR.

Flexible fabrication of biomimetic compound eye array via two-step thermal reflow of simply pre-modeled hierarchic microstructures

Science.gov (United States)

Huang, Shengzhou; Li, Mujun; Shen, Lianguan; Qiu, Jinfeng; Zhou, Youquan

2017-06-01

A flexible fabrication method for the biomimetic compound eye (BCE) array is proposed. In this method, a triple-layer sandwich-like coating configuration was introduced, and the required hierarchic microstructures are formed with a simple single-scan exposure in maskless digital lithography. Taking advantage of the difference of glass transition point (Tg) between photoresists of each layer, the pre-formed hierarchic microstructures are in turn reflowed to the curved substrate and the BCE ommatidia in a two-step thermal reflow process. To avoid affecting the spherical substrate formed in the first thermal reflow, a non-contact strategy was proposed in the second reflow process. The measurement results were in good agreement with the designed BCE profiles. Results also showed that the fabricated BCE had good performances in optical test. The presented method is flexible, convenient, low-cost and can easily adapt to the fabrications of other optical elements with hierarchic microstructures.

Thermoelectric properties of one-dimensional graphene antidot arrays

International Nuclear Information System (INIS)

Yan, Yonghong; Liang, Qi-Feng; Zhao, Hui; Wu, Chang-Qin; Li, Baowen

2012-01-01

We investigate the thermoelectric properties of one-dimensional (1D) graphene antidot arrays by nonequilibrium Green's function method. We show that by introducing antidots to the pristine graphene nanoribbon the thermal conductance can be reduced greatly while keeping the power factor still high, thus leading to an enhanced thermoelectric figure of merit (ZT). Our numerical results indicate that ZT values of 1D antidot graphene arrays can be up to unity, which means the 1D graphene antidot arrays may be promising for thermoelectric applications. -- Highlights: ► We study thermoelectric properties of one-dimensional (1D) graphene antidot arrays. ► Thermoelectric figure of merit (ZT) of 1D antidot arrays can exceed unity. ► ZT of 1D antidot arrays is larger than that of two-dimensional arrays.

Thermally Induced Vibrations of the Hubble Space Telescope's Solar Array 3 in a Test Simulated Space Environment

Science.gov (United States)

Early, Derrick A.; Haile, William B.; Turczyn, Mark T.; Griffin, Thomas J. (Technical Monitor)

2001-01-01

NASA Goddard Space Flight Center and the European Space Agency (ESA) conducted a disturbance verification test on a flight Solar Array 3 (SA3) for the Hubble Space Telescope using the ESA Large Space Simulator (LSS) in Noordwijk, the Netherlands. The LSS cyclically illuminated the SA3 to simulate orbital temperature changes in a vacuum environment. Data acquisition systems measured signals from force transducers and accelerometers resulting from thermally induced vibrations of the SAI The LSS with its seismic mass boundary provided an excellent background environment for this test. This paper discusses the analysis performed on the measured transient SA3 responses and provides a summary of the results.

The cryo-thermal therapy eradicated melanoma in mice by eliciting CD4+ T-cell-mediated antitumor memory immune response.

Science.gov (United States)

He, Kun; Liu, Ping; Xu, Lisa X

2017-03-23

Tumor metastasis is a major concern in tumor therapy. In our previous studies, a novel tumor therapeutic modality of the cryo-thermal therapy has been presented, highlighting its effect on the suppression of distal metastasis and leading to long-term survival in 4T1 murine mammary carcinoma model. To demonstrate the therapeutic efficacy in other aggressive tumor models and further investigate the mechanism of long-term survival induced, in this study, spontaneous metastatic murine B16F10 melanoma model was used. The cryo-thermal therapy induced regression of implanted melanoma and prolonged long-term survival while inhibiting lung metastasis. It also promoted the activation of CD4 + CD25 - conventional T cells, while reduced the percentage of CD4 + CD25 + regulatory T cells (Tregs) and myeloid-derived suppressor cells (MDSCs) in the spleen, lung and blood. Furthermore, the cryo-thermal therapy enhanced the cytolytic function of CD8 + T cells and induced differentiation of CD8 + T cells into memory stem T cell (T SCM ), and differentiation of CD4 + T cells into dominant CD4-CTL, Th1 and Tfh subsets in the spleen for 90 days after the treatment. It was found that good therapeutic effect was mainly dependent on CD4 + T cells providing a durable memory antitumor immune response. At the same time, significant increase of serum IFN-γ was also observed to provide an ideal microenvironment of antitumor immunity. Further study showed that the rejection of re-challenge of B16F10 but not GL261 tumor in the treated mice in 45 or 60 days after the treatment, implied a strong systemic and melanoma-specific memory antitumor immunity induced by the treatment. Thus the cryo-thermal therapy would be considered as a new therapeutic strategy to prevent tumor recurrence and metastasis with potential clinical applications in the near future.

Thermal resonance in signal transmission

International Nuclear Information System (INIS)

Reigada, Ramon; Sarmiento, Antonio; Lindenberg, Katja

2001-01-01

We use temperature tuning to control signal propagation in simple one-dimensional arrays of masses connected by hard anharmonic springs and with no local potentials. In our numerical model a sustained signal is applied at one site of a chain immersed in a thermal environment and the signal-to-noise ratio is measured at each oscillator. We show that raising the temperature can lead to enhanced signal propagation along the chain, resulting in thermal resonance effects akin to the resonance observed in arrays of bistable systems

Thermal resonance in signal transmission

Energy Technology Data Exchange (ETDEWEB)

Reigada, Ramon; Sarmiento, Antonio; Lindenberg, Katja

2001-06-01

We use temperature tuning to control signal propagation in simple one-dimensional arrays of masses connected by hard anharmonic springs and with no local potentials. In our numerical model a sustained signal is applied at one site of a chain immersed in a thermal environment and the signal-to-noise ratio is measured at each oscillator. We show that raising the temperature can lead to enhanced signal propagation along the chain, resulting in thermal resonance effects akin to the resonance observed in arrays of bistable systems.

Processes and Materials for Flexible PV Arrays

National Research Council Canada - National Science Library

Gierow, Paul

2002-01-01

.... A parallel incentive for development of flexible PV arrays are the possibilities of synergistic advantages for certain types of spacecraft, in particular the Solar Thermal Propulsion (STP) Vehicle...

WE-H-209-00: Carson/Zagzebski Distinguished Lectureship: Image Guided Ultrasound Therapy

Energy Technology Data Exchange (ETDEWEB)

NONE

2016-06-15

Focused ultrasound has been shown to be the only method that allows noninvasive thermal coagulation of tissues and recently this potential has been explored for image-guided drug delivery. In this presentation, the advances in ultrasound phased array technology for energy delivery, exposure monitoring and control will be discussed. Experimental results from novel multi-frequency transmit/receive arrays will be presented. In addition, the feasibility of fully electronically focused and steered high power arrays with many thousands of transducer elements will be discussed. Finally, some of the recent clinical and preclinical results for the treatment of brain disease will be reviewed. Learning Objectives: Introduce FUS therapy principles and modern techniques Discuss use of FUS for drug delivery Cover the technology required to deliver FUS and monitor therapy Present clinical examples of the uses of these techniques This research was supported by funding from The Canada Research Chair Program, Grants from CIHR and NIH (no. EB003268).; K. Hynynen, Canada Foundation for Innovation; Canadian Institutes of Health Research; Focused Ultrasound Surgery Foundation; Canada Research Chair Program; Natural Sciences and Engineering Research Council of Canada; Ontario Research Fund; National Institutes of Health; Canadian Cancer Society Research Institute; The Weston Brain Institute; Harmonic Medical; Focused Ultrasound Instruments.

In situ x-ray diffraction study on AgI nanowire arrays

International Nuclear Information System (INIS)

Wang Yinhai; Ye Changhui; Wang Guozhong; Zhang Lide; Liu Yanmei; Zhao Zhongyan

2003-01-01

The AgI nanowire arrays were prepared in the ordered porous alumina membrane by an electrochemical method. Transmission electron microscopy observation shows that the AgI nanowires are located in the channels of the alumina membrane. In situ x-ray diffractions show that the nanowire arrays possess hexagonal close-packed structure (β-AgI) at 293 K, orienting along the (002) plane, whereas at 473 K, the nanowire arrays possess a body-centered cubic structure (α-AgI), orienting along the (110) plane. The AgI nanowire arrays exhibit a negative thermal expansion property from 293 to 433 K, and a higher transition temperature from the β to α phase. We ascribe the negative thermal expansion behavior to the phase transition from the β to α phase, and the elevated transition temperature to the radial restriction by the channels of alumina membrane

Thermal Management of Quantum Cascade Lasers in an individually Addressable Array Architecture

Science.gov (United States)

2016-02-08

diode arrays, along with access to both front and rear facets. Hence, both laser and single-pass amplifier arrays can be accommodated. A module was... CW conditions at an emission wavelength of 9 m. OCIS codes: Semiconductor lasers , quantum cascade (140.5965), Laser arrays (140.3290) 1...Rubio, "Active coherent beam combining of diode lasers ," Opt. Lett. 36, 999-1001 (2011). 2. B. G. Saar, K. Creedon, L. Missaggia, C. A. Wang, M. K

Further development of thermal neutron capture therapy for metastatic and deeply-invasive human malignant melanoma

International Nuclear Information System (INIS)

Mishima, Yutaka

1995-03-01

This issue is the collection of the papers presented thermal neutron capture therapy for metastatic and deeply-invasive human malignant melanoma. Separate abstracts were prepared for 2 of the papers in this report. The remaining 32 papers were considered outside the subject scope of INIS. (J.P.N.)

Numerical simulation of time fractional dual-phase-lag model of heat transfer within skin tissue during thermal therapy.

Science.gov (United States)

Kumar, Dinesh; Rai, K N

2017-07-01

In this paper, we investigated the thermal behavior in living biological tissues using time fractional dual-phase-lag bioheat transfer (DPLBHT) model subjected to Dirichelt boundary condition in presence of metabolic and electromagnetic heat sources during thermal therapy. We solved this bioheat transfer model using finite element Legendre wavelet Galerkin method (FELWGM) with help of block pulse function in sense of Caputo fractional order derivative. We compared the obtained results from FELWGM and exact method in a specific case, and found a high accuracy. Results are interpreted in the form of standard and anomalous cases for taking different order of time fractional DPLBHT model. The time to achieve hyperthermia position is discussed in both cases as standard and time fractional order derivative. The success of thermal therapy in the treatment of metastatic cancerous cell depends on time fractional order derivative to precise prediction and control of temperature. The effect of variability of parameters such as time fractional derivative, lagging times, blood perfusion coefficient, metabolic heat source and transmitted power on dimensionless temperature distribution in skin tissue is discussed in detail. The physiological parameters has been estimated, corresponding to the value of fractional order derivative for hyperthermia treatment therapy. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Design, Implementation, and Performance of the Astro-H SXS Calorimeter Array and Anti-Coincidence Detector

Science.gov (United States)

Kilbourne, Caroline A.; Adams, Joseph S.; Brekosky, Regis P.; Chiao, Meng P.; Chervenak, James A.; Eckart, Megan E.; Figueroa-Feliciano, Enectali; Galeazzi, Masimilliano; Grein, Christoph; Jhabvala, Christine A.;

Temperature mapping and thermal dose calculation in combined radiation therapy and 13.56 MHz radiofrequency hyperthermia for tumor treatment

Science.gov (United States)

Kim, Jung Kyung; Prasad, Bibin; Kim, Suzy

2017-02-01

To evaluate the synergistic effect of radiotherapy and radiofrequency hyperthermia therapy in the treatment of lung and liver cancers, we studied the mechanism of heat absorption and transfer in the tumor using electro-thermal simulation and high-resolution temperature mapping techniques. A realistic tumor-induced mouse anatomy, which was reconstructed and segmented from computed tomography images, was used to determine the thermal distribution in tumors during radiofrequency (RF) heating at 13.56 MHz. An RF electrode was used as a heat source, and computations were performed with the aid of the multiphysics simulation platform Sim4Life. Experiments were carried out on a tumor-mimicking agar phantom and a mouse tumor model to obtain a spatiotemporal temperature map and thermal dose distribution. A high temperature increase was achieved in the tumor from both the computation and measurement, which elucidated that there was selective high-energy absorption in tumor tissue compared to the normal surrounding tissues. The study allows for effective treatment planning for combined radiation and hyperthermia therapy based on the high-resolution temperature mapping and high-precision thermal dose calculation.

Transition edge sensor series array bolometer

Energy Technology Data Exchange (ETDEWEB)

Beyer, J, E-mail: joern.beyer@ptb.d [Physikalisch-Technische Bundesanstalt (PTB), Abbestrasse 2-12, D-10587 Berlin (Germany)

2010-10-15

A transition edge sensor series array (TES-SA) is an array of identical TESs that are connected in series by low-inductance superconducting wiring. The array elements are equally and well thermally coupled to the absorber and respond to changes in the absorber temperature in synchronization. The TES-SA total resistance increases compared to a single TES while the shape of the superconducting transition is preserved. We are developing a TES-SA with a large number, hundreds to thousands, of array elements with the goal of enabling the readout of a TES-based bolometer operated at 4.2 K with a semiconductor-based amplifier located at room temperature. The noise and dynamic performance of a TES-SA bolometer based on a niobium/aluminum bilayer is analyzed. It is shown that stable readout of the bolometer with a low-noise transimpedance amplifier is feasible.

Transition edge sensor series array bolometer

International Nuclear Information System (INIS)

Beyer, J

2010-01-01

A transition edge sensor series array (TES-SA) is an array of identical TESs that are connected in series by low-inductance superconducting wiring. The array elements are equally and well thermally coupled to the absorber and respond to changes in the absorber temperature in synchronization. The TES-SA total resistance increases compared to a single TES while the shape of the superconducting transition is preserved. We are developing a TES-SA with a large number, hundreds to thousands, of array elements with the goal of enabling the readout of a TES-based bolometer operated at 4.2 K with a semiconductor-based amplifier located at room temperature. The noise and dynamic performance of a TES-SA bolometer based on a niobium/aluminum bilayer is analyzed. It is shown that stable readout of the bolometer with a low-noise transimpedance amplifier is feasible.

Magnetic Reversal and Thermal Stability of CoFeB Perpendicular Magnetic Tunnel Junction Arrays Patterned by Block Copolymer Lithography

KAUST Repository

Tu, Kun-Hua

2018-04-10

Dense arrays of pillars, with diameters of 64 and 25 nm, were made from a perpendicular CoFeB magnetic tunnel junction thin film stack using block copolymer lithography. While the soft layer and hard layer in the 64 nm pillars reverse at different fields, the reversal of the two layers in the 25 nm pillars could not be distinguished, attributed to the strong interlayer magnetostatic coupling. First order reversal curves were used to identify the steps that occur during switching, and the thermal stability and effective switching volume were determined from scan rate dependent hysteresis measurements.

Enhancing transformer dynamic rating through grid application of photovoltaic arrays

International Nuclear Information System (INIS)

El-Gasseir, M.M.; Sayer, M.A.; Alteneder, K.P.; McCulla, G.A.; Bigger, J.

1993-01-01

This paper demonstrates that exact matching between the substation's peak-day load profile and the profile of coincident net output generation of the PV array is unjustifiable and will unduly lead to overlooking many investment deferment opportunities that would otherwise be major components of high value applications of PV arrays. Further, the paper shows how and to what extent the load matchability requirement could be relaxed. Because of the thermal inertia of transformers, the output of an adequately sized and located photovoltaic array can both delay and reduce transformer temperature rise even in cases where load peak occurs after sunset. The time lag due to thermal inertia and ambient temperature decline allow overloading of the transformer beyond its normal rating without significant loss of life. Simulations depicting the interplay between PV array capacity, ambient temperature, transformer size, oil and winding temperature rise, peak load magnitude, load profile and loss of life, have been conducted. Tradeoffs between PV array capacity and transformer over-rating gains have been assessed. The impacts of PV generation on the over-rating potential of an actual 22.4-MVA bank transformer of a Salt River Project (SRP) distribution substation in Phoenix, Arizona were evaluated

Solar photovoltaic/thermal residential experiment. Phase I. Final report

Energy Technology Data Exchange (ETDEWEB)

Darkazalli, G.

1980-07-01

Month-by-month energy transfer data between an occupied residence and its energy supply systems are presented. The data were obtained during the first phase of photovoltaic/thermal residential research conducted at the University of Texas at Arlington/Solar Energy Research Facility. This research was part of the US Department of Energy Photovoltaic/Thermal Project managed by the M.I.T. Lincoln Laboratory. Energy transfer data are divided into different categories depending on how the energy is consumed. Energy transfers between some system components are also categorized. These components include a flat-plate thermal collector array, a flat-plate photovoltaic array, a dc-to-ac inverter, thermal storage tanks, and a series heat pump. System operations included directing surplus electrical energy (generated by the photovoltaic array) into the local utility grid. The heat pump used off-peak utility power to chill water during the cooling season.

Comparison of the performance between portal dosimetry and a commercial two-dimensional array system on pretreatment quality assurance for volumetric-modulated arc and intensity-modulated radiation therapy

International Nuclear Information System (INIS)

Kim, Yon-Lae; Chung, Jin-Beom; Kim, Jae-Sung; Lee, Jeong-Woo; Choi, Kyoung-Sik

2014-01-01

The aim of this study was to compare the dosimetric performance and to evaluate the pretreatment quality assurance (QA) of a portal dosimetry and a commercial two-dimensional (2-D) array system. In the characteristics comparison study, the measured values for the dose linearity, dose rate response, reproducibility, and field size dependence for 6-MV photon beams were analyzed for both detector systems. To perform the qualitative evaluations of the 10 IMRT and the 10 VMAT plans, we used the Gamma index for quantifying the agreement between calculations and measurements. The performance estimates for both systems show that overall, minimal differences in the dosimetric characteristics exist between the Electron portal imaging device (EPID) and 2-D array system. In the qualitative analysis for pretreatment quality assurance, the EPID and 2-D array system yield similar passing rate results for the majority of clinical Intensity-modulated radiation therapy (IMRT) and Volumetric-modulated arc therapy (VMAT) cases. These results were satisfactory for IMRT and VMAT fields and were within the acceptable criteria of γ % ≤1, γ avg < 0.5. The EPDI and the 2-D array systems showed comparable dosimetric results. In this study, the results revealed both systems to be suitable for patient-specific QA measurements for IMRT and VMAT. We conclude that, depending on the status of clinic, both systems can be used interchangeably for routine pretreatment QA.

Comparison of the performance between portal dosimetry and a commercial two-dimensional array system on pretreatment quality assurance for volumetric-modulated arc and intensity-modulated radiation therapy

Energy Technology Data Exchange (ETDEWEB)

Kim, Yon-Lae [Choonhae College of Health Sciences, Ulsan (Korea, Republic of); The Catholic University of Korea, Seoul (Korea, Republic of); Chung, Jin-Beom; Kim, Jae-Sung [Seoul National University Bundang Hospital, Seongnam (Korea, Republic of); Lee, Jeong-Woo [Konkuk University Medical Center, Seoul (Korea, Republic of); Choi, Kyoung-Sik [SAM Anyang Hospital, Anyang (Korea, Republic of)

2014-04-15

The aim of this study was to compare the dosimetric performance and to evaluate the pretreatment quality assurance (QA) of a portal dosimetry and a commercial two-dimensional (2-D) array system. In the characteristics comparison study, the measured values for the dose linearity, dose rate response, reproducibility, and field size dependence for 6-MV photon beams were analyzed for both detector systems. To perform the qualitative evaluations of the 10 IMRT and the 10 VMAT plans, we used the Gamma index for quantifying the agreement between calculations and measurements. The performance estimates for both systems show that overall, minimal differences in the dosimetric characteristics exist between the Electron portal imaging device (EPID) and 2-D array system. In the qualitative analysis for pretreatment quality assurance, the EPID and 2-D array system yield similar passing rate results for the majority of clinical Intensity-modulated radiation therapy (IMRT) and Volumetric-modulated arc therapy (VMAT) cases. These results were satisfactory for IMRT and VMAT fields and were within the acceptable criteria of γ{sub %}≤1, γ{sub avg} < 0.5. The EPDI and the 2-D array systems showed comparable dosimetric results. In this study, the results revealed both systems to be suitable for patient-specific QA measurements for IMRT and VMAT. We conclude that, depending on the status of clinic, both systems can be used interchangeably for routine pretreatment QA.

Synthesis of ordered large-scale ZnO nanopore arrays

International Nuclear Information System (INIS)

Ding, G.Q.; Shen, W.Z.; Zheng, M.J.; Fan, D.H.

2006-01-01

An effective approach is demonstrated for growing ordered large-scale ZnO nanopore arrays through radio-frequency magnetron sputtering deposition on porous alumina membranes (PAMs). The realization of highly ordered hexagonal ZnO nanopore arrays benefits from the unique properties of ZnO (hexagonal structure, polar surfaces, and preferable growth directions) and PAMs (controllable hexagonal nanopores and localized negative charges). Further evidence has been shown through the effects of nanorod size and thermal treatment of PAMs on the yielded morphology of ZnO nanopore arrays. This approach opens the possibility of creating regular semiconducting nanopore arrays for the application of filters, sensors, and templates

Enhancement of thermoelectric figure-of-merit in laterally-coupled nanowire arrays

International Nuclear Information System (INIS)

Zhang, Yiqun; Shi, Yi; Pu, Lin; Wang, Junzhuan; Pan, Lijia; Zheng, Youdou

2011-01-01

A high ZT value is predicted in laterally-coupled nanowire arrays. The quantum confinement and coupling of electrons are considered in the framework of effective-mass envelope-function theory. The boundary scattering on phonons is also taken into account. The thermoelectric properties benefit from the large Seebeck coefficient and dramatically reduced lattice thermal conductivity, as well as the preserved electronic conductivity in the minibands of the coupling nanowires. The enhancement of ZT to more than 10-fold is achieved in the n-type Si nanowires/Ge host material. Results suggest that the laterally-coupled nanowire arrays can be designed for high-performance thermoelectric devices. -- Highlights: → A high ZT value is predicted in the lateral-coupling nanowire arrays. → The lattice thermal conductivity is dramatically reduced in the lateral direction of nanowire arrays. → The electron transport is preserved in the lateral direction due to the coupling effect. → The ZT value is largely enhanced as the nanowire volume fraction exceeds some critical point.

Applying the sequential neural-network approximation and orthogonal array algorithm to optimize the axial-flow cooling system for rapid thermal processes

International Nuclear Information System (INIS)

Hung, Shih-Yu; Shen, Ming-Ho; Chang, Ying-Pin

2009-01-01

The sequential neural-network approximation and orthogonal array (SNAOA) were used to shorten the cooling time for the rapid cooling process such that the normalized maximum resolved stress in silicon wafer was always below one in this study. An orthogonal array was first conducted to obtain the initial solution set. The initial solution set was treated as the initial training sample. Next, a back-propagation sequential neural network was trained to simulate the feasible domain to obtain the optimal parameter setting. The size of the training sample was greatly reduced due to the use of the orthogonal array. In addition, a restart strategy was also incorporated into the SNAOA so that the searching process may have a better opportunity to reach a near global optimum. In this work, we considered three different cooling control schemes during the rapid thermal process: (1) downward axial gas flow cooling scheme; (2) upward axial gas flow cooling scheme; (3) dual axial gas flow cooling scheme. Based on the maximum shear stress failure criterion, the other control factors such as flow rate, inlet diameter, outlet width, chamber height and chamber diameter were also examined with respect to cooling time. The results showed that the cooling time could be significantly reduced using the SNAOA approach

Use of two-dimensional chamber arrays in volumetric modulated arc therapy treatment verification; Empleo de matrices bidimensionales de camaras de ionizacion en la verificacion de tratamientos de arcoterapia volumetrica modulada

Energy Technology Data Exchange (ETDEWEB)

Clemente Gutierrez, F.; Perez Vara, C.; Prieto Villacorta, M.; Fernandez Ruiz, M. L.; Ruiz Prados, M.

2013-09-01

Volumetric modulated arc therapy (VMAT) requires, as another kind of intensity-modulated radiation therapy (IMRT), patient-specific QA procedures. This work analyzes the method carried out in our institution for VMAT treatment verification. Our hypothesis is that traditional IMRT QA is valid for VMAT technique. Results obtained for absolute point-dose measurements with ion chamber are presented, as well as comparison with treatment planning system calculations (mean difference of (-0.50 {+-} 0.43)%). In addition, different setups with 2D ion chamber array for dose distributions comparison are analyzed. These detectors are the basis of our QA procedure. Advantages and disadvantages of those setups are shown. The present study includes results for 111 patients treated with VMAT technique from different disease sites. We conclude that 2D ion chamber arrays traditionally used in IMRT QA are valid detectors for rotational techniques if these arrays are used together with additional devices (phantoms, accessories) that allow us to obtain as much information as possible. (Author)

ZnO nanorod arrays prepared by chemical bath deposition combined with rapid thermal annealing: structural, photoluminescence and field emission characteristics

International Nuclear Information System (INIS)

Chen, Hung-Wei; He, Hsin-Min; Lee, Yi-Mu; Yang, Hsi-Wen

2016-01-01

ZnO nanorod arrays were prepared by low temperature chemical bath deposition (CBD) combined with rapid thermal annealing (RTA) under different ambient conditions. The structure and morphology of the synthesized ZnO have been characterized by field-emission scanning electron microscopy (FESEM) and x-ray diffraction (XRD). The obtained ZnO samples are highly crystalline with a hexagonal wurtzite phase and also display well-aligned array structure. A pronounced effect on increased nanorod length was found for the RTA-treated ZnO as compared to the as-grown ZnO. Analysis of XRD indicates that the (0 0 2) feature peak of the as-grown ZnO was shifted towards a lower angle as compared to the peaks of RTA-treated ZnO samples due to the reduction of tensile strain along the c-axis by RTA. Photoluminescence (PL) studies reveal that the ZnO nanorod arrays receiving RTA in an O 2 environment have the sharpest UV emission band and greatest intensity ratio of near band-edge emission (NBE) to deep level emission (DLE). Additionally, the effects of RTA on the field emission properties were evaluated. The results demonstrate that RTA an O 2 environment can lower the turn-on field and improve the field enhancement factor. The stability of the field emission current was also tested for 4 h. (paper)

Application and possible mechanisms of combining LLLT (low level laser therapy), infrared hyperthermia and ionizing radiation in the treatment of cancer

Science.gov (United States)

Abraham, Edward H.; Woo, Van H.; Harlin-Jones, Cheryl; Heselich, Anja; Frohns, Florian

2014-02-01

Benefit of concomitant infrared hyperthermia and low level laser therapy and ionizing radiation is evaluated in this study. The purpose/objectives: presentation with locally advanced bulky superficial tumors is clinically challenging. To enhance the efficacy of chemotherapy and IMRT (intensity-modulated radiation therapy) and/or electron beam therapy we have developed an inexpensive and clinically effective infrared hyperthermia approach that combines black-body infrared radiation with halogen spectrum radiation and discrete wave length infrared clinical lasers LLLT. The goal is to produce a composite spectrum extending from the far infrared to near infrared and portions of the visible spectrum with discrete penetrating wavelengths generated by the clinical infrared lasers with frequencies of 810 nm and/or 830 nm. The composite spectrum from these sources is applied before and after radiation therapy. We monitor the surface and in some cases deeper temperatures with thermal probes, but use an array of surface probes as the limiting safe thermal constraint in patient treatment while at the same time maximizing infrared entry to deeper tissue layers. Fever-grade infrared hyperthermia is produced in the first centimeters while non-thermal infrared effects act at deeper tissue layers. The combination of these effects with ionizing radiation leads to improved tumor control in many cancers.

Feasibility of salvage interstitial microwave thermal therapy for prostate carcinoma following failed brachytherapy: studies in a tissue equivalent phantom

International Nuclear Information System (INIS)

McCann, Claire; Kumaradas, J Carl; Gertner, Mark R; Davidson, Sean R H; Dolan, Alfred M; Sherar, Michael D

2003-01-01

Thermal therapy is an experimental treatment to destroy solid tumours by heating them to temperatures ranging from 55 deg C to 90 deg C, inducing thermal coagulation and necrosis of the tumour. We are investigating the feasibility of interstitial microwave thermal therapy as a salvage treatment for prostate cancer patients with local recurrence following failed brachytherapy. Due to the electrical and thermal conductivity of the brachytherapy seeds, we hypothesized that the seeds could scatter the microwave energy and cause unpredictable heating. To investigate this, a 915 MHz helical antenna was inserted into a muscle-equivalent phantom with and without brachytherapy seeds. Following a 10 W, 5 s input to the antenna, the temperature rise was used to calculate absorbed power, also referred to as specific absorption rate (SAR). Plane wave models based on Maxwell's equations were also used to characterize the electromagnetic scattering effect of the seeds. In addition, the phantom was heated with 8 W for 5 min to quantify the effect of the seeds on the temperature distribution during extended heating. SAR measurements indicated that the seeds had no significant effect on the shape and size of the SAR pattern of the antenna. However, the plane wave simulations indicated that the seeds could scatter the microwave energy resulting in hot spots at the seed edges. Lack of experimental evidence of these hot spots was probably due to the complex polarization of the microwaves emitted by the helical antenna. Extended heating experiments also demonstrated that the seeds had no significant effect on the temperature distributions and rates of temperature rise measured in the phantom. The results indicate that brachytherapy seeds are not a technical impediment to interstitial microwave thermal therapy as a salvage treatment following failed brachytherapy

A Method of Estimating Pressure and Intensity Distributions of Multielement Phased Array High Intensity Focused Ultrasonic Field at Full Power Using a Needle Hydrophone

International Nuclear Information System (INIS)

Yu Ying; Shen Guofeng; Bai Jingfeng; Chen Yazhu

2011-01-01

The pressure and intensity distribution of high intensity focused ultrasound (HIFU) fields at full power are critical for predicting heating patterns and ensuring safety of the therapy. With the limitations of maximum pressure at the hydrophone and damage from cavitation or thermal effects, it is hard to measure pressure and intensity directly when HIFU is at full power. HIFU-phased arrays are usually composed of large numbers of small elements and the sound power radiated from some of them at full power is measureable using a hydrophone, we grouped them based on the limitation of maximum permissible pressure at the hydrophone and the characteristics of the element arrangement in the array. Then sound field measurement of the group was carried out at full power level. Using the acoustic coherence principle, the pressure and intensity distribution of the array at full power level can be calculated from corresponding values from the groups. With this method, computer simulations and sound field measurement of a 65-element concentric distributed phased array was carried out. The simulation results demonstrate theoretically the feasibility of this method. Measurements on the 65-element phased array also verify the effectiveness of this method for estimating the pressure and intensity distribution of phased array at full power level using a needle hydrophone.

Multiobjective Optimization Method for Multichannel Microwave Components of Active Phased Array Antenna

Directory of Open Access Journals (Sweden)

Lu Wang

2016-01-01

Full Text Available Multichannel microwave components are widely used and the active phased array antenna is a typical representative. The high power generated from T/R modules in active phased array antenna (APAA leads to the degradation of its electrical performances, which seriously restricts the development of high-performance APAA. Therefore, to meet the demand of thermal design for APAA, a multiobjective optimization design model of cold plate is proposed. Furthermore, in order to achieve temperature uniformity and case temperature restrictions of APAA simultaneously, optimization model of channel structure is developed. Besides, an airborne active phased array antenna was tested as an example to verify the validity of the optimization model. The valuable results provide important reference for engineers to enhance thermal design technology of antennas.

Bevacizumab (Avastin and Thermal Laser Combination Therapy for Peripapillary Choroidal Neovascular Membranes

Directory of Open Access Journals (Sweden)

Sean D. Adrean

2017-01-01

Full Text Available Objective. This is a retrospective interventional case series describing the results of 5 eyes from 5 patients with symptomatic peripapillary choroidal neovascularization (CNVM receiving initial bevacizumab treatment followed by thermal laser and bevacizumab combination therapy. Methods. Patients received intravitreal bevacizumab injections until the lesions were well-defined. Thermal laser ablation was then administered and followed by an additional bevacizumab injection after one week. Visual outcomes, OCT changes, and rates of recurrence were recorded and analyzed. Results. Median visual outcomes improved from 20/50 to 20/30 (p=0.0232. Median central macular thickness decreased from 347 μm to 152 μm (p=0.0253. The mean visual improvement was 3 lines. An average of 3.8 bevacizumab injections per patient were given overall. Patients were followed for an average of 24 months, during which all eyes were absent for recurrence. Conclusion. Symptomatic peripapillary CNVM may be successfully managed with bevacizumab followed by a combination of thermal laser and bevacizumab without the need for frequent retreatment. The area requiring treatment may be better defined using bevacizumab, limiting the ablation of the healthy retina and improving treatment margins. With this treatment regimen, the patients experience improved visual outcomes and have a low rate of recurrence.

Self-assembled ordered carbon-nanotube arrays and membranes.

Energy Technology Data Exchange (ETDEWEB)

Overmyer, Donald L.; Siegal, Michael P.; Yelton, William Graham

2004-11-01

Imagine free-standing flexible membranes with highly-aligned arrays of carbon nanotubes (CNTs) running through their thickness. Perhaps with both ends of the CNTs open for highly controlled nanofiltration? Or CNTs at heights uniformly above a polymer membrane for a flexible array of nanoelectrodes or field-emitters? How about CNT films with incredible amounts of accessible surface area for analyte adsorption? These self-assembled crystalline nanotubes consist of multiple layers of graphene sheets rolled into concentric cylinders. Tube diameters (3-300 nm), inner-bore diameters (2-15 nm), and lengths (nanometers - microns) are controlled to tailor physical, mechanical, and chemical properties. We proposed to explore growth and characterize nanotube arrays to help determine their exciting functionality for Sandia applications. Thermal chemical vapor deposition growth in a furnace nucleates from a metal catalyst. Ordered arrays grow using templates from self-assembled hexagonal arrays of nanopores in anodized-aluminum oxide. Polymeric-binders can mechanically hold the CNTs in place for polishing, lift-off, and membrane formation. The stiffness, electrical and thermal conductivities of CNTs make them ideally suited for a wide-variety of possible applications. Large-area, highly-accessible gas-adsorbing carbon surfaces, superb cold-cathode field-emission, and unique nanoscale geometries can lead to advanced microsensors using analyte adsorption, arrays of functionalized nanoelectrodes for enhanced electrochemical detection of biological/explosive compounds, or mass-ionizers for gas-phase detection. Materials studies involving membrane formation may lead to exciting breakthroughs in nanofiltration/nanochromatography for the separation of chemical and biological agents. With controlled nanofilter sizes, ultrafiltration will be viable to separate and preconcentrate viruses and many strains of bacteria for 'down-stream' analysis.

MgB2-Based Bolometer Array for Far Infra-Red Thermal Imaging and Fourier Transform Spectroscopy Applications

Science.gov (United States)

Lakew, B.; Aslam, S.; Brasunas, J.

2012-01-01

The mid-superconducting critical temperature (T(sub c) approximately 39 K) of the simple binary, intermetallic MgB, [1] makes it a very good candidate for the development of the next generation of electrooptical devices (e.g. [2]). In particular, recent advances in thin film deposition teclmiques to attain higb quality polycrystalline thin film MgB, deposited on SiN-Si substrates, with T(sub c) approximately 38K [3] coupled with the low voltage noise performance of the film [4] makes it higbly desirable for the development of moderately cooled bolometer arrays for integration into future space-bourne far infra-red (FIR) spectrometers and thermal mappers for studying the outer planets, their icy moons and other moons of interest in the 17-250 micrometer spectral wavelength range. Presently, commercially available pyroelectric detectors operating at 300 K have specific detectivity, D(*), around 7 x 10(exp 8) to 2 x 10(exp 9) centimeters square root of Hz/W. However, a MgB2 thin film based bolometer using a low-stress (less than 140 MPa) SiN membrane isolated from the substrate by a small thermal conductive link, operating at 38 K, promises to have two orders of magnitude higher specific detectivity [5][6].

Copper-encapsulated vertically aligned carbon nanotube arrays.

Science.gov (United States)

Stano, Kelly L; Chapla, Rachel; Carroll, Murphy; Nowak, Joshua; McCord, Marian; Bradford, Philip D

2013-11-13

A new procedure is described for the fabrication of vertically aligned carbon nanotubes (VACNTs) that are decorated, and even completely encapsulated, by a dense network of copper nanoparticles. The process involves the conformal deposition of pyrolytic carbon (Py-C) to stabilize the aligned carbon-nanotube structure during processing. The stabilized arrays are mildly functionalized using oxygen plasma treatment to improve wettability, and they are then infiltrated with an aqueous, supersaturated Cu salt solution. Once dried, the salt forms a stabilizing crystal network throughout the array. After calcination and H2 reduction, Cu nanoparticles are left decorating the CNT surfaces. Studies were carried out to determine the optimal processing parameters to maximize Cu content in the composite. These included the duration of Py-C deposition and system process pressure as well as the implementation of subsequent and multiple Cu salt solution infiltrations. The optimized procedure yielded a nanoscale hybrid material where the anisotropic alignment from the VACNT array was preserved, and the mass of the stabilized arrays was increased by over 24-fold because of the addition of Cu. The procedure has been adapted for other Cu salts and can also be used for other metal salts altogether, including Ni, Co, Fe, and Ag. The resulting composite is ideally suited for application in thermal management devices because of its low density, mechanical integrity, and potentially high thermal conductivity. Additionally, further processing of the material via pressing and sintering can yield consolidated, dense bulk composites.

Magnetomotive optical coherence elastography (MM-OCE) for thermal therapy dosimetry (Conference Presentation)

Science.gov (United States)

Huang, Pin-Chieh; Marjanovic, Marina; Spillman, Darold R.; Odintsov, Boris M.; Boppart, Stephen A.

2016-03-01

Biomechanical properties of tissues have been utilized for disease detection, diagnosis, and progression, however they have not been extensively utilized for therapy dosimetry. Magnetic hyperthermia aims to kill cells and ablate tumors using magnetic nanoparticles (MNPs) either injected in or targeted to tumors. Upon application of an appropriate AC magnetic field, MNPs can heat target tissue while sparing non-targeted healthy tissue. However, a sensitive monitoring technique for the dose of magnetic hyperthermia is needed to prevent over-treatment and collateral injury. During hyperthermia treatments, the viscoelastic properties of tissues are altered due to protein denaturation, coagulation, and tissue dehydration, making these properties candidates for dosimetry. Magnetomotive optical coherence elastography (MM-OCE) utilizes MNPs as internal force transducers to probe the biomechanical properties of tissues. Therefore, we aim to evaluate the hyperthermia dose based on the elastic changes revealed by MM-OCE. In this study, MNPs embedded in tissues were utilized for both hyperthermia and MM-OCE measurements. Tissue temperature and elastic modulus were obtained, where the elastic modulus was extracted from the resonance frequency detected by MM-OCE. Results showed a correlation between stiffness and temperature change following treatment. To investigate the thermal-dose-dependent changes, intervals of hyperthermia treatment were repeatedly performed on the same tissue sequentially, interspersed with MM-OCE. With increasing times of treatment, tissue stiffness increased, while temperature rise remained relatively constant. These results suggest that MM-OCE may potentially identify reversible and irreversible tissue changes during thermal therapy, supporting the use of MM-OCE for dosimetric control of hyperthermia in future applications.

Simulating the Sky as Seen by the Square Kilometer Array using the MIT Array Performance Simulator (MAPS)

Science.gov (United States)

Matthews, Lynn D.; Cappallo, R. J.; Doeleman, S. S.; Fish, V. L.; Lonsdale, C. J.; Oberoi, D.; Wayth, R. B.

2009-05-01

The Square Kilometer Array (SKA) is a proposed next-generation radio telescope that will operate at frequencies of 0.1-30 GHz and be 50-100 times more sensitive than existing radio arrays. Meeting the performance goals of this instrument will require innovative new hardware and software developments, a variety of which are now under consideration. Key to evaluating the performance characteristics of proposed SKA designs and testing the feasibility of new data calibration and processing algorithms is the ability to carry out realistic simulations of radio wavelength arrays under a variety of observing conditions. The MIT Array Performance Simulator (MAPS) (http://www.haystack.mit.edu/ast/arrays/maps/index.html) is an observations simulation package designed to achieve this goal. MAPS accepts an input source list or sky model and generates a model visibility set for a user-defined "virtual observatory'', incorporating such factors as array geometry, primary beam shape, field-of-view, and time and frequency resolution. Optionally, effects such as thermal noise, out-of-beam sources, variable station beams, and time/location-dependent ionospheric effects can be included. We will showcase current capabilities of MAPS for SKA applications by presenting results from an analysis of the effects of realistic sky backgrounds on the achievable image fidelity and dynamic range of SKA-like arrays comprising large numbers of small-diameter antennas.

Fabrication of close-packed TES microcalorimeter arrays using superconducting molybdenum/gold transition-edge sensors

Science.gov (United States)

Finkbeiner, F. M.; Brekosky, R. P.; Chervenak, J. A.; Figueroa-Feliciano, E.; Li, M. J.; Lindeman, M. A.; Stahle, C. K.; Stahle, C. M.; Tralshawala, N.

2002-02-01

We present an overview of our efforts in fabricating Transition-Edge Sensor (TES) microcalorimeter arrays for use in astronomical x-ray spectroscopy. Two distinct types of array schemes are currently pursued: 5×5 single pixel TES array where each pixel is a TES microcalorimeter, and Position-Sensing TES (PoST) array. In the latter, a row of 7 or 15 thermally-linked absorber pixels is read out by two TES at its ends. Both schemes employ superconducting Mo/Au bilayers as the TES. The TES are placed on silicon nitride membranes for thermal isolation from the structural frame. The silicon nitride membranes are prepared by a Deep Reactive Ion Etch (DRIE) process into a silicon wafer. In order to achieve the concept of closely packed arrays without decreasing its structural and functional integrity, we have already developed the technology to fabricate arrays of cantilevered pixel-sized absorbers and slit membranes in silicon nitride films. Furthermore, we have started to investigate ultra-low resistance through-wafer micro-vias to bring the electrical contact out to the back of a wafer. .

Design of hyper-thermal neutron irradiation fields for neutron capture therapy in KUR-heavy water neutron irradiation facility. Mounting of hyper-thermal neutron converter in therapeutic collimator

International Nuclear Information System (INIS)

Sakurai, Y.; Kobayashi, T.

2001-01-01

Neutron capture therapy (NCP) using thermal neutron needs to improve of depth dose distribution in a living body. Epi-thermal neutron following moderation of fast neutron is usually used for improving of the depth dose distribution. The moderation method of fast neutron, however, gets mixed some of high energy neutron which give some of serious effects to a living body, and involves the difficulty for collimation of thermal neutron to the diseased part. Hyper-thermal neutrons, which are in an energy range of 0.1-3 eV at high temperature side of thermal neutron, are under consideration for application to the NCP. The hyper-thermal neutrons can be produced by up-scattering of thermal neutron in a high temperature material. Fast neutron components in collimator for the NCP reduce on application of the up-scattering method. Graphite at high temperature (>1000k) is used as a hyper-thermal neutron converter. The hyper-thermal neutron converter is planted to mount on therapeutic collimator which is located at the nearest side of patient for the NCP. Total neutron flux, ratio of hyper-thermal neutron to total neutron, and ratio of gamma-ray dose to neutron flux are calculated as a function of thickness of the graphite converter using monte carlo code MCNP-V4B. (M. Suetake)

Advanced thermal management materials

CERN Document Server

Jiang, Guosheng; Kuang, Ken

2012-01-01

""Advanced Thermal Management Materials"" provides a comprehensive and hands-on treatise on the importance of thermal packaging in high performance systems. These systems, ranging from active electronically-scanned radar arrays to web servers, require components that can dissipate heat efficiently. This requires materials capable of dissipating heat and maintaining compatibility with the packaging and dye. Its coverage includes all aspects of thermal management materials, both traditional and non-traditional, with an emphasis on metal based materials. An in-depth discussion of properties and m

The Next-Generation Very Large Array: Technical Overview

Science.gov (United States)

McKinnon, Mark; Selina, Rob

2018-01-01

As part of its mandate as a national observatory, the NRAO is looking toward the long range future of radio astronomy and fostering the long term growth of the US astronomical community. NRAO has sponsored a series of science and technical community meetings to consider the science mission and design of a next-generation Very Large Array (ngVLA), building on the legacies of the Atacama Large Millimeter/submillimeter Array (ALMA) and the Very Large Array (VLA).The basic ngVLA design emerging from these discussions is an interferometric array with approximately ten times the sensitivity and ten times higher spatial resolution than the VLA and ALMA radio telescopes, optimized for operation in the wavelength range 0.3cm to 3cm. The ngVLA would open a new window on the Universe through ultra-sensitive imaging of thermal line and continuum emission down to milli-arcsecond resolution, as well as unprecedented broadband continuum polarimetric imaging of non-thermal processes. The specifications and concepts for major ngVLA system elements are rapidly converging.We will provide an overview of the current system design of the ngVLA. The concepts for major system elements such as the antenna, receiving electronics, and central signal processing will be presented. We will also describe the major development activities that are presently underway to advance the design.

Highly selective gas sensor arrays based on thermally reduced graphene oxide.

Science.gov (United States)

Lipatov, Alexey; Varezhnikov, Alexey; Wilson, Peter; Sysoev, Victor; Kolmakov, Andrei; Sinitskii, Alexander

2013-06-21

The electrical properties of reduced graphene oxide (rGO) have been previously shown to be very sensitive to surface adsorbates, thus making rGO a very promising platform for highly sensitive gas sensors. However, poor selectivity of rGO-based gas sensors remains a major problem for their practical use. In this paper, we address the selectivity problem by employing an array of rGO-based integrated sensors instead of focusing on the performance of a single sensing element. Each rGO-based device in such an array has a unique sensor response due to the irregular structure of rGO films at different levels of organization, ranging from nanoscale to macroscale. The resulting rGO-based gas sensing system could reliably recognize analytes of nearly the same chemical nature. In our experiments rGO-based sensor arrays demonstrated a high selectivity that was sufficient to discriminate between different alcohols, such as methanol, ethanol and isopropanol, at a 100% success rate. We also discuss a possible sensing mechanism that provides the basis for analyte differentiation.

Solar cell array design handbook - The principles and technology of photovoltaic energy conversion

Science.gov (United States)

Rauschenbach, H. S.

1980-01-01

Photovoltaic solar cell array design and technology for ground-based and space applications are discussed from the user's point of view. Solar array systems are described, with attention given to array concepts, historical development, applications and performance, and the analysis of array characteristics, circuits, components, performance and reliability is examined. Aspects of solar cell array design considered include the design process, photovoltaic system and detailed array design, and the design of array thermal, radiation shielding and electromagnetic components. Attention is then given to the characteristics and design of the separate components of solar arrays, including the solar cells, optical elements and mechanical elements, and the fabrication, testing, environmental conditions and effects and material properties of arrays and their components are discussed.

Developing the ultimate biomimetic flow-sensor array

NARCIS (Netherlands)

Bruinink, C.M.; Jaganatharaja, R.K.; de Boer, Meint J.; Berenschot, Johan W.; Kolster, M.L.; Lammerink, Theodorus S.J.; Wiegerink, Remco J.; Krijnen, Gijsbertus J.M.

2009-01-01

This contribution reports on the major developments and achievements in our group on fabricating highly sensitive biomimetic flow-sensor arrays. The mechanoreceptive sensory hairs of crickets are taken as a model system for their ability to perceive flow signals at thermal noise levels and,

Extremely Black Vertically Aligned Carbon Nanotube Arrays for Solar Steam Generation.

Science.gov (United States)

Yin, Zhe; Wang, Huimin; Jian, Muqiang; Li, Yanshen; Xia, Kailun; Zhang, Mingchao; Wang, Chunya; Wang, Qi; Ma, Ming; Zheng, Quan-Shui; Zhang, Yingying

2017-08-30

The unique structure of a vertically aligned carbon nanotube (VACNT) array makes it behave most similarly to a blackbody. It is reported that the optical absorptivity of an extremely black VACNT array is about 0.98-0.99 over a large spectral range of 200 nm-200 μm, inspiring us to explore the performance of VACNT arrays in solar energy harvesting. In this work, we report the highly efficient steam generation simply by laminating a layer of VACNT array on the surface of water to harvest solar energy. It is found that under solar illumination the temperature of upper water can significantly increase with obvious water steam generated, indicating the efficient solar energy harvesting and local temperature rise by the thin layer of VACNTs. We found that the evaporation rate of water assisted by VACNT arrays is 10 times that of bare water, which is the highest ratio for solar-thermal-steam generation ever reported. Remarkably, the solar thermal conversion efficiency reached 90%. The excellent performance could be ascribed to the strong optical absorption and local temperature rise induced by the VACNT layer, as well as the ultrafast water transport through the VACNT layer due to the frictionless wall of CNTs. Based on the above, we further demonstrated the application of VACNT arrays in solar-driven desalination.

Thermally Conductive Tape Based on Carbon Nanotube Array, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — Future NASA missions require thermal control systems that can accommodate large changes in ambient temperature. The two essential aspects of an effective thermal...

SWIFT BAT Loop Heat Pipe Thermal System Characteristics and Ground/Flight Operation Procedure

Science.gov (United States)

Choi, Michael K.

2003-01-01

The SWIFT Burst Alert Telescope (BAT) Detector Array has a total power dissipation of 208 W. To meet the stringent temperature gradient and thermal stability requirements in the normal operational mode, and heater power budget in both the normal operational and safehold modes, the Detector Array is thermally well coupled to eight constant conductance heat pipes (CCHPs) embedded in the Detector Array Plate (DAP), and two loop heat pipes (LHPs) transport heat fiom the CCHPs to a radiator. The CCHPs have ammonia as the working fluid and the LHPs have propylene as the working fluid. Precision heater controllers, which have adjustable set points in flight, are used to control the LHP compensation chamber and Detector Array XA1 ASIC temperatures. The radiator has the AZ-Tek AZW-LA-II low-alpha white paint as the thermal coating and is located on the anti-sun side of the spacecraft. This paper presents the characteristics, ground operation and flight operation procedures of the LHP thermal system.

Impact of Improved Heat Sinking of an X-Ray Calorimeter Array on Crosstalk, Noise, and Background Events

Science.gov (United States)

Kilbourne, C. A.; Adams, J. S.; Brekosky, R. P.; Chervenak, J. A.; Chiao, M. P.; Kelley, R. L.; Kelly, D. P.; Porter, F. S.

2011-01-01

The x-ray calorimeter array of the Soft X-ray Spectrometer (SXS) of the Astro-H satellite will incorporate a silicon thermistor array produced during the development of the X-Ray Spectrometer (XRS) of the Suzaku satellite. On XRS, inadequate heat sinking of the array led to several non-ideal effects. The thermal crosstalk, while too small to be confused with x-ray signals, nonetheless contributed a noise term that could be seen as a degradation in energy resolution at high flux. When energy was deposited in the silicon frame around the active elements of the array, such as by a cosmic ray, the resulting pulse in the temperature of the frame resulted in coincident signal pulses on most of the pixels. In orbit, the resolution was found to depend on the particle background rate. In order to minimize these effects on SXS, heat-sinking gold was applied to areas on the front and back of the array die, which was thermally anchored to the gold of its fanout board via gold wire bonds. The thermal conductance from the silicon chip to the fanout board was improved over that of XRS by an order of magnitude. This change was sufficient for essentially eliminating frame events and allowing high-resolution to be attained at much higher counting rates. We will present the improved performance, the measured crosstalk, and the results of the thermal characterization of such arrays.

Intraoperative boron neutron capture therapy for malignant gliomas. First clinical results of Tsukuba phase I/II trial using JAERI mixed thermal-epithermal beam

International Nuclear Information System (INIS)

Matsumura, A.; Yamamoto, T.; Shibata, Y.

2000-01-01

Since October 1999, a clinical trial of intraoperative boron neutron capture therapy (IOBNCT) is in progress at JRR-4 (Japan Research Reactor-4) in Japan Atomic Energy Research Institute (JAERI) using mixed thermal-epithermal beam (thermal neutron beam I: TNB-I). Compared to pure thermal beam (thermal neutron beam II: TNB-II), TNB-I has an improved neutron delivery into the deep region than TNB-II. The clinical protocol and the preliminary results will be discussed. (author)

One-dimensional arrays of oscillators: Energy localization in thermal equilibrium

International Nuclear Information System (INIS)

Reigada, R.; Romero, A.H.; Sarmiento, A.; Lindenberg, K.

1999-01-01

All systems in thermal equilibrium exhibit a spatially variable energy landscape due to thermal fluctuations. Thus at any instant there is naturally a thermodynamically driven localization of energy in parts of the system relative to other parts of the system. The specific characteristics of the spatial landscape such as, for example, the energy variance, depend on the thermodynamic properties of the system and vary from one system to another. The temporal persistence of a given energy landscape, that is, the way in which energy fluctuations (high or low) decay toward the thermal mean, depends on the dynamical features of the system. We discuss the spatial and temporal characteristics of spontaneous energy localization in 1D anharmonic chains in thermal equilibrium. copyright 1999 American Institute of Physics

Micropatterned arrays of porous silicon: toward sensory biointerfaces.

Science.gov (United States)

Flavel, Benjamin S; Sweetman, Martin J; Shearer, Cameron J; Shapter, Joseph G; Voelcker, Nicolas H

2011-07-01

We describe the fabrication of arrays of porous silicon spots by means of photolithography where a positive photoresist serves as a mask during the anodization process. In particular, photoluminescent arrays and porous silicon spots suitable for further chemical modification and the attachment of human cells were created. The produced arrays of porous silicon were chemically modified by means of a thermal hydrosilylation reaction that facilitated immobilization of the fluorescent dye lissamine, and alternatively, the cell adhesion peptide arginine-glycine-aspartic acid-serine. The latter modification enabled the selective attachment of human lens epithelial cells on the peptide functionalized regions of the patterns. This type of surface patterning, using etched porous silicon arrays functionalized with biological recognition elements, presents a new format of interfacing porous silicon with mammalian cells. Porous silicon arrays with photoluminescent properties produced by this patterning strategy also have potential applications as platforms for in situ monitoring of cell behavior.

CFD investigations of data centers’ thermal performance for different configurations of CRACs units and aisles separation

Directory of Open Access Journals (Sweden)

S.A. Nada

2016-06-01

Full Text Available The thermal performance of data centers is numerically studied for different configurations of computer room air conditioning (CRAC units and physical separations of cold and hot aisles. Temperature distribution, air flow characteristics and thermal management of data centers racks array are predicted and evaluated for the different arrangements. Measureable performance indices: supply/return heat index (SHI/RHI, return temperature index (RTI and return cooling index (RCI are used to measure the thermal management effectiveness of data center racks. The results showed that: (i hot air recirculation, cold air bypass and the measurable performance indices of the racks strongly depend on the racks location in the racks array, (ii the CRACs units layout affects the thermal managements of the racks array especially the sides and middle racks in the array, and (iii using cold aisle containments enhances the thermal performance of the data center.

Rectenna thermal model development

Science.gov (United States)

Kadiramangalam, Murall; Alden, Adrian; Speyer, Daniel

1992-01-01

Deploying rectennas in space requires adapting existing designs developed for terrestrial applications to the space environment. One of the major issues in doing so is to understand the thermal performance of existing designs in the space environment. Toward that end, a 3D rectenna thermal model has been developed, which involves analyzing shorted rectenna elements and finite size rectenna element arrays. A shorted rectenna element is a single element whose ends are connected together by a material of negligible thermal resistance. A shorted element is a good approximation to a central element of a large array. This model has been applied to Brown's 2.45 GHz rectenna design. Results indicate that Brown's rectenna requires redesign or some means of enhancing the heat dissipation in order for the diode temperature to be maintained below 200 C above an output power density of 620 W/sq.m. The model developed in this paper is very general and can be used for the analysis and design of any type of rectenna design of any frequency.

Development of a spherically focused phased array transducer for ultrasonic image-guided hyperthermia

OpenAIRE

Liu, Jingfei; Foiret, Josquin; Stephens, Douglas N.; Le Baron, Olivier; Ferrara, Katherine W.

2016-01-01

A 1.5 MHz prolate spheroidal therapeutic array with 128 circular elements was designed to accommodate standard imaging arrays for ultrasonic image-guided hyperthermia. The implementation of this dual-array system integrates real-time therapeutic and imaging functions with a single ultrasound system (Vantage 256, Verasonics). To facilitate applications involving small animal imaging and therapy the array was designed to have a beam depth of field smaller than 3.5 mm and to electronically steer...

HIFU Monitoring and Control with Dual-Mode Ultrasound Arrays

Science.gov (United States)

Casper, Andrew Jacob

The biological effects of high-intensity focused ultrasound (HIFU) have been known and studied for decades. HIFU has been shown capable of treating a wide variety of diseases and disorders. However, despite its demonstrated potential, HIFU has been slow to gain clinical acceptance. This is due, in part, to the difficulty associated with robustly monitoring and controlling the delivery of the HIFU energy. The non-invasive nature of the surgery makes the assessment of treatment progression difficult, leading to long treatment times and a significant risk of under treatment. This thesis research develops new techniques and systems for robustly monitoring HIFU therapies for the safe and efficacious delivery of the intended treatment. Systems and algorithms were developed for the two most common modes of HIFU delivery systems: single-element and phased array applicators. Delivering HIFU with a single element transducer is a widely used technique in HIFU therapies. The simplicity of a single element offers many benefits in terms of cost and overall system complexity. Typical monitoring schemes rely on an external device (e.g. diagnostic ultrasound or MRI) to assess the progression of therapy. The research presented in this thesis explores using the same element to both deliver and monitor the HIFU therapy. The use of a dual-mode ultrasound transducer (DMUT) required the development of an FPGA based single-channel arbitrary waveform generator and high-speed data acquisition unit. Data collected from initial uncontrolled ablations led to the development of monitoring and control algorithms which were implemented directly on the FPGA. Close integration between the data acquisition and arbitrary waveform units allowed for fast, low latency control over the ablation process. Results are presented that demonstrate control of HIFU therapies over a broad range of intensities and in multiple in vitro tissues. The second area of investigation expands the DMUT research to an

Improving Reliability of High Power Quasi-CW Laser Diode Arrays for Pumping Solid State Lasers

Science.gov (United States)

Amzajerdian, Farzin; Meadows, Byron L.; Baker, Nathaniel R.; Barnes, Bruce W.; Baggott, Renee S.; Lockard, George E.; Singh, Upendra N.; Kavaya, Michael J.

2005-01-01

Most Lidar applications rely on moderate to high power solid state lasers to generate the required transmitted pulses. However, the reliability of solid state lasers, which can operate autonomously over long periods, is constrained by their laser diode pump arrays. Thermal cycling of the active regions is considered the primary reason for rapid degradation of the quasi-CW high power laser diode arrays, and the excessive temperature rise is the leading suspect in premature failure. The thermal issues of laser diode arrays are even more drastic for 2-micron solid state lasers which require considerably longer pump pulses compared to the more commonly used pump arrays for 1-micron lasers. This paper describes several advanced packaging techniques being employed for more efficient heat removal from the active regions of the laser diode bars. Experimental results for several high power laser diode array devices will be reported and their performance when operated at long pulsewidths of about 1msec will be described.

Study of solar array switching power management technology for space power system

Science.gov (United States)

Cassinelli, J. E.

1982-01-01

This report documents work performed on the Solar Array Switching Power Management Study. Mission characteristics for three missions were defined to the depth necessary to determine their power management requirements. Solar array switching concepts which could satisfy the mission requirements were identified. The switching concepts were compared with a conventional buck regulator system for cost, weight and volume, reliability, efficiency and thermal control. Solar array switching provided significant advantages in all areas of comparison for the reviewed missions.

A general melt-injection-decomposition route to oriented metal oxide nanowire arrays

International Nuclear Information System (INIS)

Han, Dongqiang; Zhang, Xinwei; Hua, Zhenghe; Yang, Shaoguang

2016-01-01

Highlights: • A general melt-injection-decomposition (MID) route is proposed for the fabrication of oriented metal oxide nanowire arrays. • Four kinds of metal oxide (CuO, Mn_2O_3, Co_3O_4 and Cr_2O_3) nanowire arrays have been realized as examples through the developed MID route. • The mechanism of the developed MID route is discussed using Thermogravimetry and Differential Thermal Analysis technique. • The MID route is a versatile, simple, facile and effective way to prepare different kinds of oriented metal oxide nanowire arrays in the future. - Abstract: In this manuscript, a general melt-injection-decomposition (MID) route has been proposed and realized for the fabrication of oriented metal oxide nanowire arrays. Nitrate was used as the starting materials, which was injected into the nanopores of the anodic aluminum oxide (AAO) membrane through the capillarity action in its liquid state. At higher temperature, the nitrate decomposed into corresponding metal oxide within the nanopores of the AAO membrane. Oriented metal oxide nanowire arrays were formed within the AAO membrane as a result of the confinement of the nanopores. Four kinds of metal oxide (CuO, Mn_2O_3, Co_3O_4 and Cr_2O_3) nanowire arrays are presented here as examples fabricated by this newly developed process. X-ray diffraction, scanning electron microscopy and transmission electron microscopy studies showed clear evidence of the formations of the oriented metal oxide nanowire arrays. Formation mechanism of the metal oxide nanowire arrays is discussed based on the Thermogravimetry and Differential Thermal Analysis measurement results.

An efficient route to Cu_2O nanorod array film for high-performance Li-ion batteries

International Nuclear Information System (INIS)

Yang, Yumei; Wang, Kun; Yang, Zeheng; Zhang, Yingmeng; Gu, Heyun; Zhang, Weixin; Li, Errui; Zhou, Chen

2016-01-01

Fabrication of well-organized one-dimensional nanostructured arrays on conducting substrates as binder free electrodes allows us to synergize and integrate multi-functionalities into lithium ion batteries. In this contribution, we report a metal-induced thermal reduction (MITR) method to prepare free-standing Cu_2O nanorod array film with average diameters of 400 ± 100 nm and lengths of several microns on copper substrates by direct thermal reduction of Cu(OH)_2 nanorod arrays on copper foils in nitrogen atmosphere at 500 °C. The presence of Cu substrates reduces the Cu(OH)_2 to Cu_2O and decreases the reduction temperature significantly through changing the reaction Gibbs energy. Compared with some previously-reported methods about thermal reduction, the MITR method is facile, controllable, efficient and low energy consumption. The free-standing Cu_2O nanorod array film on Cu substrates as anode can achieve high rate capability (315 mAh g"−"1 at 10 C) and good cyclability (358 mAh g"−"1 after 200 cycles at 1 C), demonstrating their excellent electrochemical performance in lithium ion batteries, which results from relatively faster electron and ion transport, easier electrolyte diffusion and better accommodation of strains from the repeated conversion reactions based on their one-dimensional nanostructured arrays. - Highlights: • A metal-induced thermal reduction method was used to prepare Cu_2O nanorod array film. • Copper substrate takes an important part in the conversion of Cu(OH)_2 to Cu_2O. • The Cu_2O films show excellent electrochemical properties as anode for Li-ion battery.

Multifunctional Material Structures Based on Laser-Etched Carbon Nanotube Arrays

Directory of Open Access Journals (Sweden)

Aline Emplit

2014-09-01

Full Text Available High-power electronics in the transportation and aerospace sectors need size and weight reduction. Multifunctional and multistructured materials are currently being developed to couple electromagnetic (EM and thermal properties, i.e., shielding against electromagnetic impulsions, and thermal management across the thermal interface material (TIM. In this work, we investigate laser-machined patterned carbon nanotube (CNT micro-brushes as an alternative to metallic structures for driving simultaneously EM and heat propagation. The thermal and electromagnetic response of the CNT array is expected to be sensitive to the micro-structured pattern etched in the CNT brush.

SU-F-J-215: Non-Thermal Pulsed High Intensity Focused Ultrasound Therapy Combined with 5-Aminolevulinic Acid: An in Vivo Pilot Study

Energy Technology Data Exchange (ETDEWEB)

Wang, B; He, W; Cvetkovic, D; Chen, L; Ma, C [Fox Chase Cancer Center, Philadelphia, PA (United States)

2016-06-15

Purpose: It has recently been shown that non-thermal pulsed high intensity focused ultrasound (pHIFU) has a cell-killing effect. The purpose of the study is to investigate the sonosensitizing effect of 5-Aminolevulinic Acid (5-ALA) in non-thermal pHIFU cancer therapy. Methods: FaDu human head and neck squamous cell carcinoma cells were injected subcutaneously in the flanks of nude mice. After one to two weeks, the tumors reached the volume of 112 ± 8 mm3 and were assigned randomly into a non-thermal pHIFU group (n=9) and a non-thermal sonodynamic therapy (pHIFU after 5-ALA administration) group (n=7). The pHIFU treatments (parameters: 1 MHz frequency; 25 W acoustic power; 0.1 duty cycle; 60 seconds duration) were delivered using an InSightec ExAblate 2000 system with a GE Signa 1.5T MR scanner. The mice in the non-thermal sonodynamic group received 5-ALA tail-vein injection 4 hours prior to the pHIFU treatment. The tumor growth was monitored using the CT scanner on a Sofie-Biosciences G8 PET/CT system. Results: The tumors in this study grew very aggressively and about 60% of the tumors in this study developed ulcerations at various stages. Tumor growth delay after treatments was observed by comparing the treated (n=9 in pHIFU group; n=7 in sonodynamic group) and untreated tumors (n=17). However, no statistically significant differences were found between the non-thermal pHIFU and non-thermal sonodynamic group. The mean normalized tumor volume of the untreated tumors on Day 7 after their first CT scans was 7.05 ± 0.54, while the normalized volume of the treated tumors on Day 7 after treatment was 5.89 ± 0.79 and 6.27 ± 0.47 for the sonodynamic group and pHIFU group, respectively. Conclusion: In this study, no significant sonosensitizing effects of 5-ALA were obtained on aggressive FaDu tumors despite apparent tumor growth delay in some mice treated with non-thermal sonodynamic therapy.

Custom ceramic microchannel-cooled array for high-power fiber-coupled application

Science.gov (United States)

Junghans, Jeremy; Feeler, Ryan; Stephens, Ed

2018-03-01

A low-SWaP (Size, Weight and Power) diode array has been developed for a high-power fiber-coupled application. High efficiency ( 65%) diodes enable high optical powers while minimizing thermal losses. A large amount of waste heat is still generated and must be extracted. Custom ceramic microchannel-coolers (MCCs) are used to dissipate the waste heat. The custom ceramic MCC was designed to accommodate long cavity length diodes and micro-lenses. The coolers provide similar thermal performance as copper MCCs however they are not susceptible to erosion and can be cooled with standard filtered water. The custom ceramic micro-channel cooled array was designed to be a form/fit replacement for an existing copperbased solution. Each array consisted of three-vertically stacked MCCs with 4 mm CL, 976 nm diodes and beamshaping micro-optics. The erosion and corrosion resistance of ceramic array is intended to mitigate the risk of copperbased MCC corrosion failures. Elimination of the water delivery requirements (pH, resistivity and dissolved oxygen control) further reduces the system SWaP while maintaining reliability. The arrays were fabricated and fully characterized. This work discusses the advantages of the ceramic MCC technology and describes the design parameters that were tailored for the fiber-coupled application. Additional configuration options (form/fit, micro-lensing, alternate coolants, etc.) and on-going design improvements are also discussed.

Fabrication of gold-nanoparticle arrays using photolithography and thermal dewetting

NARCIS (Netherlands)

de Vreede, Lennart; Göeken, Kristian; Göeken, Kristian; Gill, Ron; Gill, Ron; van den Berg, Albert; Eijkel, Jan C.T.; Zengerle, R.

2013-01-01

We demonstrate a new manufacturing method using only basic cleanroom techniques to produce an array of 106 100 nm diameter gold-nanoparticles (GNPs) of equal shape and 5 μm spacing on a fused silica surface. Photolithography and sputtering are used to produce gold islets, followed by a simple

SEP solar array Shuttle flight experiment

Science.gov (United States)

Elms, R. V., Jr.; Young, L. E.; Hill, H. C.

1981-01-01

An experiment to verify the operational performance of a full-scale Solar Electric Propulsion (SEP) solar array is described. Scheduled to fly on the Shuttle in 1983, the array will be deployed from the bay for ten orbits, with dynamic excitation to test the structural integrity being furnished by the Orbiter verniers; thermal, electrical, and sun orientation characteristics will be monitored, in addition to safety, reliability, and cost effective performance. The blanket, with aluminum and glass as solar cell mass simulators, is 4 by 32 m, with panels (each 0.38 by 4 m) hinged together; two live Si cell panels will be included. The panels are bonded to stiffened graphite-epoxy ribs and are storable in a box in the bay. The wing support structure is detailed, noting the option of releasing the wing into space by use of the Remote Manipulator System if the wing cannot be refolded. Procedures and equipment for monitoring the array behavior are outlined, and comprise both analog data and TV recording for later playback and analysis. The array wing experiment will also aid in developing measurement techniques for large structure dynamics in space.

A general melt-injection-decomposition route to oriented metal oxide nanowire arrays

Energy Technology Data Exchange (ETDEWEB)

Han, Dongqiang; Zhang, Xinwei; Hua, Zhenghe; Yang, Shaoguang, E-mail: sgyang@nju.edu.cn

2016-12-30

Highlights: • A general melt-injection-decomposition (MID) route is proposed for the fabrication of oriented metal oxide nanowire arrays. • Four kinds of metal oxide (CuO, Mn{sub 2}O{sub 3}, Co{sub 3}O{sub 4} and Cr{sub 2}O{sub 3}) nanowire arrays have been realized as examples through the developed MID route. • The mechanism of the developed MID route is discussed using Thermogravimetry and Differential Thermal Analysis technique. • The MID route is a versatile, simple, facile and effective way to prepare different kinds of oriented metal oxide nanowire arrays in the future. - Abstract: In this manuscript, a general melt-injection-decomposition (MID) route has been proposed and realized for the fabrication of oriented metal oxide nanowire arrays. Nitrate was used as the starting materials, which was injected into the nanopores of the anodic aluminum oxide (AAO) membrane through the capillarity action in its liquid state. At higher temperature, the nitrate decomposed into corresponding metal oxide within the nanopores of the AAO membrane. Oriented metal oxide nanowire arrays were formed within the AAO membrane as a result of the confinement of the nanopores. Four kinds of metal oxide (CuO, Mn{sub 2}O{sub 3}, Co{sub 3}O{sub 4} and Cr{sub 2}O{sub 3}) nanowire arrays are presented here as examples fabricated by this newly developed process. X-ray diffraction, scanning electron microscopy and transmission electron microscopy studies showed clear evidence of the formations of the oriented metal oxide nanowire arrays. Formation mechanism of the metal oxide nanowire arrays is discussed based on the Thermogravimetry and Differential Thermal Analysis measurement results.

Electrical power system integrated thermal/electrical system simulation

International Nuclear Information System (INIS)

Freeman, W.E.

1992-01-01

This paper adds thermal properties to previously developed electrical Saber templates and incorporates these templates into a functional Electrical Power Subsystem (EPS) simulation. These combined electrical and thermal templates enable the complete and realistic simulation of a vehicle EPS on-orbit. Applications include on-orbit energy balance determinations for system load changes, initial array and battery EPS sizing for new EPS development, and array and battery technology trade studies. This effort proves the versatility of the Saber simulation program in handling varied and complex simulations accurately and in a reasonable amount of computer time. 9 refs

Structural anomalies induced by the metal deposition methods in 2D silver nanoparticle arrays prepared by nanosphere lithography

Energy Technology Data Exchange (ETDEWEB)

Huang, Shengli, E-mail: huangsl@xmu.edu.cn [Fujian Provincial Key Lab of Semiconductors and Applications, Department of Physics, Xiamen University, Xiamen, Fujian 361005 (China); State Key Lab of Silicon Materials, Zhejiang University, Hangzhou 310027 (China); Yang, Qianqian [Fujian Provincial Key Lab of Semiconductors and Applications, Department of Physics, Xiamen University, Xiamen, Fujian 361005 (China); State Key Lab of Silicon Materials, Zhejiang University, Hangzhou 310027 (China); Zhang, Chunjing; Kong, Lingqi; Li, Shuping; Kang, Junyong [Fujian Provincial Key Lab of Semiconductors and Applications, Department of Physics, Xiamen University, Xiamen, Fujian 361005 (China)

2013-06-01

Silver nanoparticle arrays with 2-dimensional hexagonal arrangement were fabricated on the silicon substrates by nanosphere lithography. The silver film was deposited either by thermal evaporation or by magnetron sputtering under different conditions. The nanostructures of the achieved sphere template and the array units were characterized by scanning electron microscopy and atomic force microscopy, and were found to be anomalous under different deposition parameters. Comparative study indicated that the formation of the various 2-dimensional silver nanoparticle array structures was dominated by the thermal energy (temperature), kinetic energy and deposition direction of the deposited metal atoms as well as the size and nanocurvature of the colloidal particles and the metal clusters. - Highlights: • Silver nanoparticle arrays with different nanostructures on silicon substrates. • Various deposition parameters in arrays formation systematically examined. • Possible mechanisms and optimization of nanostructures formation addressed.

Space Environment Testing of Photovoltaic Array Systems at NASA's Marshall Space Flight Center

Science.gov (United States)

Phillips, Brandon S.; Schneider, Todd A.; Vaughn, Jason A.; Wright, Kenneth H., Jr.

2015-01-01

To successfully operate a photovoltaic (PV) array system in space requires planning and testing to account for the effects of the space environment. It is critical to understand space environment interactions not only on the PV components, but also the array substrate materials, wiring harnesses, connectors, and protection circuitry (e.g. blocking diodes). Key elements of the space environment which must be accounted for in a PV system design include: Solar Photon Radiation, Charged Particle Radiation, Plasma, and Thermal Cycling. While solar photon radiation is central to generating power in PV systems, the complete spectrum includes short wavelength ultraviolet components, which photo-ionize materials, as well as long wavelength infrared which heat materials. High energy electron radiation has been demonstrated to significantly reduce the output power of III-V type PV cells; and proton radiation damages material surfaces - often impacting coverglasses and antireflective coatings. Plasma environments influence electrostatic charging of PV array materials, and must be understood to ensure that long duration arcs do not form and potentially destroy PV cells. Thermal cycling impacts all components on a PV array by inducing stresses due to thermal expansion and contraction. Given such demanding environments, and the complexity of structures and materials that form a PV array system, mission success can only be ensured through realistic testing in the laboratory. NASA's Marshall Space Flight Center has developed a broad space environment test capability to allow PV array designers and manufacturers to verify their system's integrity and avoid costly on-orbit failures. The Marshall Space Flight Center test capabilities are available to government, commercial, and university customers. Test solutions are tailored to meet the customer's needs, and can include performance assessments, such as flash testing in the case of PV cells.

Column Grid Array Rework for High Reliability

Science.gov (United States)

Mehta, Atul C.; Bodie, Charles C.

2008-01-01

Due to requirements for reduced size and weight, use of grid array packages in space applications has become common place. To meet the requirement of high reliability and high number of I/Os, ceramic column grid array packages (CCGA) were selected for major electronic components used in next MARS Rover mission (specifically high density Field Programmable Gate Arrays). ABSTRACT The probability of removal and replacement of these devices on the actual flight printed wiring board assemblies is deemed to be very high because of last minute discoveries in final test which will dictate changes in the firmware. The questions and challenges presented to the manufacturing organizations engaged in the production of high reliability electronic assemblies are, Is the reliability of the PWBA adversely affected by rework (removal and replacement) of the CGA package? and How many times can we rework the same board without destroying a pad or degrading the lifetime of the assembly? To answer these questions, the most complex printed wiring board assembly used by the project was chosen to be used as the test vehicle, the PWB was modified to provide a daisy chain pattern, and a number of bare PWB s were acquired to this modified design. Non-functional 624 pin CGA packages with internal daisy chained matching the pattern on the PWB were procured. The combination of the modified PWB and the daisy chained packages enables continuity measurements of every soldered contact during subsequent testing and thermal cycling. Several test vehicles boards were assembled, reworked and then thermal cycled to assess the reliability of the solder joints and board material including pads and traces near the CGA. The details of rework process and results of thermal cycling are presented in this paper.

Reliability of Ceramic Column Grid Array Interconnect Packages Under Extreme Temperatures

Science.gov (United States)

Ramesham, Rajeshuni

2011-01-01

A paper describes advanced ceramic column grid array (CCGA) packaging interconnects technology test objects that were subjected to extreme temperature thermal cycles. CCGA interconnect electronic package printed wiring boards (PWBs) of polyimide were assembled, inspected nondestructively, and, subsequently, subjected to ex - treme-temperature thermal cycling to assess reliability for future deep-space, short- and long-term, extreme-temperature missions. The test hardware consisted of two CCGA717 packages with each package divided into four daisy-chained sections, for a total of eight daisy chains to be monitored. The package is 33 33 mm with a 27 27 array of 80%/20% Pb/Sn columns on a 1.27-mm pitch. The change in resistance of the daisy-chained CCGA interconnects was measured as a function of the increasing number of thermal cycles. Several catastrophic failures were observed after 137 extreme-temperature thermal cycles, as per electrical resistance measurements, and then the tests were continued through 1,058 thermal cycles to corroborate and understand the test results. X-ray and optical inspection have been made after thermal cycling. Optical inspections were also conducted on the CCGA vs. thermal cycles. The optical inspections were conclusive; the x-ray images were not. Process qualification and assembly is required to optimize the CCGA assembly, which is very clear from the x-rays. Six daisy chains were open out of seven daisy chains, as per experimental test data reported. The daisy chains are open during the cold cycle, and then recover during the hot cycle, though some of them also opened during the hot thermal cycle..

Thermal crosstalk investigation in an integrated InP multiwavelength laser

NARCIS (Netherlands)

Gilardi, G.; Wale, M.J.; Smit, M.K.

2012-01-01

We numerically investigate the thermal crosstalk effects in an integrated InP multiwavelength laser. The multiwavelength laser under investigation consists of a number of Distributed Bragg Reflector lasers and an Arrayed Waveguide Grating. Each laser generates a fixed wavelength and the Arrayed

Thermalization and cooling of plasmon-exciton polaritons : towards quantum condensation

NARCIS (Netherlands)

Rodriguez, S.R.K.; Feist, J.; Verschuuren, M.A.; Garcia Vidal, F.J.; Gomez Rivas, J.

2013-01-01

We present indications of thermalization and cooling of quasiparticles, a precursor for quantum condensation, in a plasmonic nanoparticle array. We investigate a periodic array of metallic nanorods covered by a polymer layer doped with an organic dye at room temperature. Surface lattice resonances

Tailoring Thermal Radiative Properties with Doped-Silicon Nanowires

Energy Technology Data Exchange (ETDEWEB)

Zhang, Zhuomin [Georgia Inst. of Technology, Atlanta, GA (United States)

2017-08-28

Aligned doped-silicon nanowire (D-SiNW) arrays form a hyperbolic metamaterial in the mid-infrared and have unique thermal radiative properties, such as broadband omnidirectional absorption, low-loss negative refraction, etc. A combined theoretical and experimental investigation will be performed to characterize D-SiNW arrays and other metamaterials for tailoring thermal radiative properties. Near-field thermal radiation between anisotropic materials with hyperbolic dispersions will also be predicted for potential application in energy harvesting. A new kind of anisotropic metamaterial with a hyperbolic dispersion in a broad infrared region has been proposed and demonstrated based on aligned doped-silicon nanowire (D-SiNW) arrays. D-SiNW-based metamaterials have unique thermal radiative properties, such as broadband omnidirectional absorption whose width and location can be tuned by varying the filling ratio and/or doping level. Furthermore, high figure of merit (FOM) can be achieved in a wide spectral region, suggesting that D-SiNW arrays may be used as a negative refraction material with much less loss than other structured materials, such as layered semiconductor materials. We have also shown that D-SiNWs and other nanostructures can significantly enhance near-field thermal radiation. The study of near-field radiative heat transfer between closely spaced objects and the electromagnetic wave interactions with micro/nanostructured materials has become an emerging multidisciplinary field due to its importance in advanced energy systems, manufacturing, local thermal management, and high spatial resolution thermal sensing and mapping. We have performed extensive study on the energy streamlines involving anisotropic metamaterials and the applicability of the effective medium theory for near-field thermal radiation. Graphene as a 2D material has attracted great attention in nanoelectronics, plasmonics, and energy harvesting. We have shown that graphene can be used to

Comparison of Thermal Detector Arrays for Off-Axis THz Holography and Real-Time THz Imaging

Directory of Open Access Journals (Sweden)

Erwin Hack

2016-02-01

Full Text Available In terahertz (THz materials science, imaging by scanning prevails when low power THz sources are used. However, the application of array detectors operating with high power THz sources is increasingly reported. We compare the imaging properties of four different array detectors that are able to record THz radiation directly. Two micro-bolometer arrays are designed for infrared imaging in the 8–14 μm wavelength range, but are based on different absorber materials (i vanadium oxide; (ii amorphous silicon; (iii a micro-bolometer array optimized for recording THz radiation based on silicon nitride; and (iv a pyroelectric array detector for THz beam profile measurements. THz wavelengths of 96.5 μm, 118.8 μm, and 393.6 μm from a powerful far infrared laser were used to assess the technical performance in terms of signal to noise ratio, detector response and detectivity. The usefulness of the detectors for beam profiling and digital holography is assessed. Finally, the potential and limitation for real-time digital holography are discussed.

Comparison of Thermal Detector Arrays for Off-Axis THz Holography and Real-Time THz Imaging.

Science.gov (United States)

Hack, Erwin; Valzania, Lorenzo; Gäumann, Gregory; Shalaby, Mostafa; Hauri, Christoph P; Zolliker, Peter

2016-02-06

In terahertz (THz) materials science, imaging by scanning prevails when low power THz sources are used. However, the application of array detectors operating with high power THz sources is increasingly reported. We compare the imaging properties of four different array detectors that are able to record THz radiation directly. Two micro-bolometer arrays are designed for infrared imaging in the 8-14 μm wavelength range, but are based on different absorber materials (i) vanadium oxide; (ii) amorphous silicon; (iii) a micro-bolometer array optimized for recording THz radiation based on silicon nitride; and (iv) a pyroelectric array detector for THz beam profile measurements. THz wavelengths of 96.5 μm, 118.8 μm, and 393.6 μm from a powerful far infrared laser were used to assess the technical performance in terms of signal to noise ratio, detector response and detectivity. The usefulness of the detectors for beam profiling and digital holography is assessed. Finally, the potential and limitation for real-time digital holography are discussed.

Role of magnetic resonance imaging in guiding thermal therapies. A brief technical review

International Nuclear Information System (INIS)

Kuroda, Kagayaki

2007-01-01

For a number of reasons, Magnetic Resonance Imaging (MRI) is a unique tool for interventional use. It has a spatial resolution which is independent of the wavelength of the electromagnetic field used for imaging, has various imaging parameters which are related to the physical properties of the subject; provides a superior soft-tissue contrast; provides freedom in determining the slicing or viewing angle; and it utilizes non-ionizing radiation. This technology offers assistance in therapeutic applications such as lesion identification, treatment planning, device tracking, temperature imaging and treatment evaluation. In this article, the role of MRI in assisting thermal therapy is briefly reviewed from a technical point of view. (author)

Multi-Channel RF System for MRI-Guided Transurethral Ultrasound Thermal Therapy

Science.gov (United States)

Yak, Nicolas; Asselin, Matthew; Chopra, Rajiv; Bronskill, Michael

2009-04-01

MRI-guided transurethral ultrasound thermal therapy is an approach to treating localized prostate cancer which targets precise deposition of thermal energy within a confined region of the gland. This treatment requires a system incorporating a heating applicator with multiple planar ultrasound transducers and associated RF electronics to control individual elements independently in order to achieve accurate 3D treatment. We report the design, construction, and characterization of a prototype multi-channel system capable of controlling 16 independent RF signals for a 16-element heating applicator. The main components are a control computer, microcontroller, and a 16-channel signal generator with 16 amplifiers, each incorporating a low-pass filter and transmitted/reflected power detection circuit. Each channel can deliver from 0.5 to 10 W of electrical power and good linearity from 3 to 12 MHz. Harmonic RF signals near the Larmor frequency of a 1.5 T MRI were measured to be below -30 dBm and heating experiments within the 1.5 T MR system showed no significant decrease in SNR of the temperature images. The frequency and power for all 16 channels could be changed in less than 250 ms, which was sufficiently rapid for proper performance of the control algorithms. A common backplane design was chosen which enabled an inexpensive, modular approach for each channel resulting in an overall system with minimal footprint.

Generic nano-imprint process for fabrication of nanowire arrays

Energy Technology Data Exchange (ETDEWEB)

Pierret, Aurelie; Hocevar, Moira; Algra, Rienk E; Timmering, Eugene C; Verschuuren, Marc A; Immink, George W G; Verheijen, Marcel A; Bakkers, Erik P A M [Philips Research Laboratories Eindhoven, High Tech Campus 11, 5656 AE Eindhoven (Netherlands); Diedenhofen, Silke L [FOM Institute for Atomic and Molecular Physics c/o Philips Research Laboratories, High Tech Campus 4, 5656 AE Eindhoven (Netherlands); Vlieg, E, E-mail: e.p.a.m.bakkers@tue.nl [IMM, Solid State Chemistry, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen (Netherlands)

2010-02-10

A generic process has been developed to grow nearly defect-free arrays of (heterostructured) InP and GaP nanowires. Soft nano-imprint lithography has been used to pattern gold particle arrays on full 2 inch substrates. After lift-off organic residues remain on the surface, which induce the growth of additional undesired nanowires. We show that cleaning of the samples before growth with piranha solution in combination with a thermal anneal at 550 deg. C for InP and 700 deg. C for GaP results in uniform nanowire arrays with 1% variation in nanowire length, and without undesired extra nanowires. Our chemical cleaning procedure is applicable to other lithographic techniques such as e-beam lithography, and therefore represents a generic process.

Micromachined two dimensional resistor arrays for determination of gas parameters

NARCIS (Netherlands)

van Baar, J.J.J.; Verwey, Willem B.; Dijkstra, Mindert; Dijkstra, Marcel; Wiegerink, Remco J.; Lammerink, Theodorus S.J.; Krijnen, Gijsbertus J.M.; Elwenspoek, Michael Curt

A resistive sensor array is presented for two dimensional temperature distribution measurements in a micromachined flow channel. This allows simultaneous measurement of flow velocity and fluid parameters, like thermal conductivity, diffusion coefficient and viscosity. More general advantages of

Formation of precise 2D Au particle arrays via thermally induced dewetting on pre-patterned substrates

Directory of Open Access Journals (Sweden)

Dong Wang

2011-06-01

Full Text Available The fabrication of precise 2D Au nanoparticle arrays over a large area is presented. The technique was based on pre-patterning of the substrate before the deposition of a thin Au film, and the creation of periodic particle arrays by subsequent dewetting induced by annealing. Two types of pre-patterned substrates were used: The first comprised an array of pyramidal pits and the second an array of circular holes. For the dewetting of Au films on the pyramidal pit substrate, the structural curvature-driven diffusion cooperates with capillarity-driven diffusion, resulting in the formation of precise 2D particle arrays for films within a structure dependent thickness-window. For the dewetting of Au films on the circular hole substrate, the periodic discontinuities in the films, induced by the deposition, can limit the diffusion paths and lead to the formation of one particle per individual separated region (holes or mesas between holes, and thus, result in the evolution of precise 2D particle arrays. The influence of the pre-patterned structures and the film thickness is analyzed and discussed. For both types of pre-patterned substrate, the Au film thickness had to be adjusted in a certain thickness-window in order to achieve the precise 2D particle arrays.

Formation of precise 2D Au particle arrays via thermally induced dewetting on pre-patterned substrates

Science.gov (United States)

Ji, Ran

2011-01-01

Summary The fabrication of precise 2D Au nanoparticle arrays over a large area is presented. The technique was based on pre-patterning of the substrate before the deposition of a thin Au film, and the creation of periodic particle arrays by subsequent dewetting induced by annealing. Two types of pre-patterned substrates were used: The first comprised an array of pyramidal pits and the second an array of circular holes. For the dewetting of Au films on the pyramidal pit substrate, the structural curvature-driven diffusion cooperates with capillarity-driven diffusion, resulting in the formation of precise 2D particle arrays for films within a structure dependent thickness-window. For the dewetting of Au films on the circular hole substrate, the periodic discontinuities in the films, induced by the deposition, can limit the diffusion paths and lead to the formation of one particle per individual separated region (holes or mesas between holes), and thus, result in the evolution of precise 2D particle arrays. The influence of the pre-patterned structures and the film thickness is analyzed and discussed. For both types of pre-patterned substrate, the Au film thickness had to be adjusted in a certain thickness-window in order to achieve the precise 2D particle arrays. PMID:21977445

Heat Sinking, Cross Talk, and Temperature Stability for Large, Close-Packed Arrays of Microcalorimeters

Science.gov (United States)

Imoto, Naoko; Bandler, SImon; Brekosky, Regis; Chervenak, James; Figueroa-Felicano, Enectali; Finkbeiner, Frederick; Kelley, Richard; Kilbourne, Caroline; Porter, Frederick; Sadleir, Jack;

Thermal-mechanical deformation modelling of soft tissues for thermal ablation.

Science.gov (United States)

Li, Xin; Zhong, Yongmin; Jazar, Reza; Subic, Aleksandar

2014-01-01

Modeling of thermal-induced mechanical behaviors of soft tissues is of great importance for thermal ablation. This paper presents a method by integrating the heating process with thermal-induced mechanical deformations of soft tissues for simulation and analysis of the thermal ablation process. This method combines bio-heat transfer theories, constitutive elastic material law under thermal loads as well as non-rigid motion dynamics to predict and analyze thermal-mechanical deformations of soft tissues. The 3D governing equations of thermal-mechanical soft tissue deformation are discretized by using the finite difference scheme and are subsequently solved by numerical algorithms. Experimental results show that the proposed method can effectively predict the thermal-induced mechanical behaviors of soft tissues, and can be used for the thermal ablation therapy to effectively control the delivered heat energy for cancer treatment.

Transport in arrays of submicron Josephson junctions over a ground plane

Energy Technology Data Exchange (ETDEWEB)

Ho, Teressa Rae [Univ. of California, Berkeley, CA (United States)

1997-12-01

One-dimensional (1D) and two-dimensional (2D) arrays of Al islands linked by submicron Al/Al_xO_y/Al tunnel junctions were fabricated on an insulating layer grown on a ground plane. The arrays were cooled to temperatures as low as 20 mK where the Josephson coupling energy E_J of each junction and the charging energy E_C of each island were much greater than the thermal energy k_BT. The capacitance C_g between each island and the ground plane was much greater than the junction capacitance C. Two classes of arrays were studied. In the first class, the normal state tunneling resistance of the junctions was much larger than the resistance quantum for single electrons, R_N>> R_Qe≡ h/e² ~ 25.8 kΩ, and the islands were driven normal by an applied magnetic field such that E_J = 0 and the array was in the Coulomb blockade regime. The arrays were made on degenerately-doped Si, thermally oxidized to a thickness of approximately 100 nm. The current-voltage (I - V) characteristics of a 1D and a 2D array were measured and found to display a threshold voltage V_T below which little current flows. In the second class of arrays, the normal state tunneling resistance of the junctions was close to the resistance quantum for Cooper pairs, R_N≈R_Q≡h/4e²≈6.45kΩ, such that E_J/E_C≈1. The arrays were made on GaAs/Al_0.3Ga_0.7As heterostructures with a two-dimensional electron gas approximately 100 nm below the surface. One array displayed superconducting behavior at low temperature. Two arrays displayed insulating behavior at low temperature, and the size of the Coulomb gap increased with increasing R_g.

Elastomeric thermal interface materials with high through-plane thermal conductivity from carbon fiber fillers vertically aligned by electrostatic flocking.

Science.gov (United States)

Uetani, Kojiro; Ata, Seisuke; Tomonoh, Shigeki; Yamada, Takeo; Yumura, Motoo; Hata, Kenji

2014-09-03

Electrostatic flocking is applied to create an array of aligned carbon fibers from which an elastomeric thermal interface material (TIM) can be fabricated with a high through-plane thermal conductivity of 23.3 W/mK. A high thermal conductivity can be achieved with a significantly low filler level (13.2 wt%). As a result, this material retains the intrinsic properties of the matrix, i.e., elastomeric behavior. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Design and testing of a combustion-heated nineteen-converter SAVTEC array

International Nuclear Information System (INIS)

Nyren, T.; Fitzpatrick, G.O.; Korringa, M.; McVey, J.; Sahines, T.

1984-01-01

The SAVTEC (Self-Adjusting Versatile Thermionic Energy Converter) is a new design approach for achieving very close (<12μ) interelectrode spacing in a thermionic converter. Techniques were developed for fabricating an array of nineteen SAVTEC converters. The array was incorporated in an SiC protective ''hot shell'' which also served as a radiant heat source for the emitter of each converter. The completed assembly was tested with a specially constructed combustion heat source. Electric output was generated by sixteen of the nineteen converters, despite poor thermal contact in a cooling block, which resulted in high collector temperatures. Details of the array design and test results are described

Solar panels offer array of hope.

Science.gov (United States)

Baillie, Jonathan

2009-01-01

The installation of what is believed to be the largest array of solar thermal panels currently in use at a UK NHS hospital has taken place at an ideal time for the facility in question, Harlow's Princess Alexandra Hospital, with the hospital's gas bill alone having risen by 153% over the past nine months thanks to soaring energy prices, and the estates department keen to mitigate the effects in any way possible. Jonathan Baillie reports.

Array capabilities and future arrays

International Nuclear Information System (INIS)

Radford, D.

1993-01-01

Early results from the new third-generation instruments GAMMASPHERE and EUROGAM are confirming the expectation that such arrays will have a revolutionary effect on the field of high-spin nuclear structure. When completed, GAMMASHPERE will have a resolving power am order of magnitude greater that of the best second-generation arrays. When combined with other instruments such as particle-detector arrays and fragment mass analysers, the capabilites of the arrays for the study of more exotic nuclei will be further enhanced. In order to better understand the limitations of these instruments, and to design improved future detector systems, it is important to have some intelligible and reliable calculation for the relative resolving power of different instrument designs. The derivation of such a figure of merit will be briefly presented, and the relative sensitivities of arrays currently proposed or under construction presented. The design of TRIGAM, a new third-generation array proposed for Chalk River, will also be discussed. It is instructive to consider how far arrays of Compton-suppressed Ge detectors could be taken. For example, it will be shown that an idealised open-quote perfectclose quotes third-generation array of 1000 detectors has a sensitivity an order of magnitude higher again than that of GAMMASPHERE. Less conventional options for new arrays will also be explored

Mechanism for wettability alteration of ZnO nanorod arrays via thermal annealing in vacuum and air

International Nuclear Information System (INIS)

Zhang Jun; Liu Yanru; Wei Zhiyang; Zhang Junyan

2013-01-01

Highlights: ► Oxygen vacancy is the key factor in accounting for the change in morphology of the ZnO nanorod arrays. ► We firstly investigated the wettability alteration of ZnO nanorod arrays annealed in vacuum at different temperature. ► The hydrophilicity of the ZnO nanorod arrays annealed in air is not related to the oxygen vacancy but ascribed to the O adatom on the nanorod surface. - Abstract: The ZnO nanorod arrays were synthesized via a simple hydrothermal process followed by annealing in vacuum and air respectively at different temperature. The wettability of samples was controlled by adjusting the annealing atmosphere and temperature. To investigate the mechanism of wettability alteration, the chemical composition and surface morphology of nanorod arrays were analyzed by X-ray photoelectron spectroscopy (XPS) and field emission scanning electron microscopy (FE-SEM), respectively. Increasing oxygen vacancy concentration by increasing annealing temperature in vacuum resulted in a great change of surface morphology, which played the major role in wettability change. Under annealing in air, oxygen vacancy concentration reduced and the surface morphology of nanorod arrays showed little change with increasing annealing temperature. The wettability alteration is ascribed to the O adatom on the nanorods surface.

Micro-array collimators for X-rays and neutrons

International Nuclear Information System (INIS)

Cimmino, A.; Allman, B.E.; Klein, A.G.; Bastie, P.

1998-08-01

The authors describe the fabrication techniques of novel, compact optical elements for collimating and/or focusing beams of X-rays or thermal neutrons. These optical elements are solid composite arrays consisting of regular stacks of alternating micro-foils, analogous in action to Soller slit collimators, but up to three orders of magnitude smaller. The arrays are made of alternating metals with suitable refractive indices for reflection and/or absorption of the specific radiation. In one implementation, the arrays are made of stacked micro-foils of transmissive elements (Al, Cu) coated and/or electroplated with absorbing elements (Gd, Cd), which are repeatedly rolled or drawn and restacked to achieve the required collimation parameters. The authors present results of these collimators using both X-rays and neutrons. The performance of the collimating element is limited only by the choice of micro-foil materials and the uniformity of their interfaces

Uncooled infrared focal plane array imaging in China

Science.gov (United States)

Lei, Shuyu

2015-06-01

This article reviews the development of uncooled infrared focal plane array (UIFPA) imaging in China in the past decade. Sensors based on optical or electrical read-out mechanism were developed but the latter dominates the market. In resistive bolometers, VOx and amorphous silicon are still the two major thermal-sensing materials. The specifications of the IRFPA made by different manufactures were collected and compared. Currently more than five Chinese companies and institutions design and fabricate uncooled infrared focal plane array. Some devices have sensitivity as high as 30 mK; the largest array for commercial products is 640×512 and the smallest pixel size is 17 μm. Emphasis is given on the pixel MEMS design, ROIC design, fabrication, and packaging of the IRFPA manufactured by GWIC, especially on design for high sensitivities, low noise, better uniformity and linearity, better stabilization for whole working temperature range, full-digital design, etc.

Identification of Tequila with an Array of ZnO Thin Films: A Simple and Cost-Effective Method

Directory of Open Access Journals (Sweden)

Pedro Estanislao Acuña-Avila

2017-12-01

Full Text Available An array of ZnO thin film sensors was obtained by thermal oxidation of physical vapor deposited thin Zn films. Different conditions of the thermal treatment (duration and temperature were applied in view of obtaining ZnO sensors with different gas sensing properties. Films having undergone a long thermal treatment exhibited high responses to low ethanol concentrations, while short thermal treatments generally led to sensors with high ethanol sensitivity. The sensor array was used to distinguish among Tequilas and Agave liquor. Linear discriminant analysis and the multilayer perceptron neural network reached 100% and 86.3% success rates in the discrimination between real Tequila and Agave liquor and in the identification of Tequila brands, respectively. These results are promising for the development of an inexpensive tool offering low complexity and cost of analysis for detecting fraud in spirits.

SU-F-BRCD-08: Uncertainty Quantification by Generalized Polynomial Chaos for MR-Guided Laser Induced Thermal Therapy.

Science.gov (United States)

Fahrenholtz, S; Fuentes, D; Stafford, R; Hazle, J

2012-06-01

Magnetic resonance-guided laser induced thermal therapy (MRgLITT) is a minimally invasive thermal treatment for metastatic brain lesions, offering an alternative to conventional surgery. The purpose of this investigation is to incorporate uncertainty quantification (UQ) into the biothermal parameters used in the Pennes bioheat transfer equation (BHT), in order to account for imprecise values available in the literature. The BHT is a partial differential equation commonly used in thermal therapy models. MRgLITT was performed on an in vivo canine brain in a previous investigation. The canine MRgLITT was modeled using the BHT. The BHT has four parameters'" microperfusion, conductivity, optical absorption, and optical scattering'"which lack precise measurements in living brain and tumor. The uncertainties in the parameters were expressed as probability distribution functions derived from literature values. A univariate generalized polynomial chaos (gPC) expansion was applied to the stochastic BHT. The gPC approach to UQ provides a novel methodology to calculate spatio-temporal voxel-wise means and variances of the predicted temperature distributions. The performance of the gPC predictions were evaluated retrospectively by comparison with MR thermal imaging (MRTI) acquired during the MRgLITT procedure in the canine model. The comparison was evaluated with root mean square difference (RMSD), isotherm contours, spatial profiles, and z-tests. The peak RMSD was ∼1.5 standard deviations for microperfusion, conductivity, and optical absorption, while optical scattering was ∼2.2 standard deviations. Isotherm contours and spatial profiles of the simulation's predicted mean plus or minus two standard deviations demonstrate the MRTI temperature was enclosed by the model's isotherm confidence interval predictions. An a = 0.01 z-test demonstrates agreement. The application of gPC for UQ is a potentially powerful means for providing predictive simulations despite poorly known

SU-E-T-644: Evaluation of Angular Dependence Correction for 2D Array Detector Using for Quality Assurance of Volumetric Modulated Arc Therapy

International Nuclear Information System (INIS)

Karthikeyan, N; Ganesh, K M; Vikraman, S; Shariff, MH

2014-01-01

Purpose: To evaluate the angular dependence correction for Matrix Evolution 2D array detector in quality assurance of volumetric modulated arc therapy(VMAT). Methods: Total ten patients comprising of different sites were planned for VMAT and taken for the study. Each plan was exposed on Matrix Evolution 2D array detector with Omnipro IMRT software based on the following three different methods using 6MV photon beams from Elekta Synergy linear accelerator. First method, VMAT plan was delivered on Matrix Evolution detector as it gantry mounted with dedicated holder with build-up of 2.3cm. Second, the VMAT plan was delivered with the static gantry angle on to the table mounted setup. Third, the VMAT plan was delivered with actual gantry angle on Matrix Evolution detector fixed in Multicube phantom with gantry angle sensor and angular dependence correction were applied to quantify the plan quality. For all these methods, the corresponding QA plans were generated in TPS and the dose verification was done for both point and 2D fluence analysis with pass criteria of 3% dose difference and 3mm distance to agreement. Results: The measured point dose variation for the first method was observed as 1.58±0.6% of mean and SD with TPS calculated. For second and third method, the mean and standard deviation(SD) was observed as 1.67±0.7% and 1.85±0.8% respectively. The 2D fluence analysis of measured and TPS calculated has the mean and SD of 97.9±1.1%, 97.88±1.2% and 97.55±1.3% for first, second and third methods respectively. The calculated two-tailed Pvalue for point dose and 2D fluence analysis shows the insignificance with values of 0.9316 and 0.9015 respectively, among the different methods of QA. Conclusion: The qualitative evaluation of angular dependence correction for Matrix Evolution 2D array detector shows its competency in accuracy of quality assurance measurement of composite dose distribution of volumetric modulated arc therapy

A silicon strip detector array for energy verification and quality assurance in heavy ion therapy.

Science.gov (United States)

Debrot, Emily; Newall, Matthew; Guatelli, Susanna; Petasecca, Marco; Matsufuji, Naruhiro; Rosenfeld, Anatoly B

2018-02-01

The measurement of depth dose profiles for range and energy verification of heavy ion beams is an important aspect of quality assurance procedures for heavy ion therapy facilities. The steep dose gradients in the Bragg peak region of these profiles require the use of detectors with high spatial resolution. The aim of this work is to characterize a one dimensional monolithic silicon detector array called the "serial Dose Magnifying Glass" (sDMG) as an independent ion beam energy and range verification system used for quality assurance conducted for ion beams used in heavy ion therapy. The sDMG detector consists of two linear arrays of 128 silicon sensitive volumes each with an effective size of 2mm × 50μm × 100μm fabricated on a p-type substrate at a pitch of 200 μm along a single axis of detection. The detector was characterized for beam energy and range verification by measuring the response of the detector when irradiated with a 290 MeV/u 12 C ion broad beam incident along the single axis of the detector embedded in a PMMA phantom. The energy of the 12 C ion beam incident on the detector and the residual energy of an ion beam incident on the phantom was determined from the measured Bragg peak position in the sDMG. Ad hoc Monte Carlo simulations of the experimental setup were also performed to give further insight into the detector response. The relative response profiles along the single axis measured with the sDMG detector were found to have good agreement between experiment and simulation with the position of the Bragg peak determined to fall within 0.2 mm or 1.1% of the range in the detector for the two cases. The energy of the beam incident on the detector was found to vary less than 1% between experiment and simulation. The beam energy incident on the phantom was determined to be (280.9 ± 0.8) MeV/u from the experimental and (280.9 ± 0.2) MeV/u from the simulated profiles. These values coincide with the expected energy of 281 MeV/u. The sDMG detector

Three nights leg thermal therapy could improve sleep quality in patients with chronic heart failure.

Science.gov (United States)

Sawatari, Hiroyuki; Nishizaka, Mari K; Miyazono, Mami; Ando, Shin-Ichi; Inoue, Shujiro; Takemoto, Masao; Sakamoto, Takafumi; Goto, Daisuke; Furumoto, Tomoo; Kinugawa, Shintaro; Hashiguchi, Nobuko; Rahmawati, Anita; Chishaki, Hiroaki; Ohkusa, Tomoko; Magota, Chie; Tsutsui, Hiroyuki; Chishaki, Akiko

2018-02-01

Sleep quality is often impaired in patients with chronic heart failure (HF), which may worsen their quality of life and even prognosis. Leg thermal therapy (LTT), topical leg warming, has been shown to improve endothelial function, oxidative stress, and cardiac function in patients with HF. However, its short-term influence to sleep quality has not been evaluated in HF patients. Eighteen of 23 patients with stable HF received LTT (15 min of warming at 45 °C and 30 min of insulation) at bedtime for 3 consecutive nights and 5 patients served as control. Subjective sleep quality was evaluated by St. Mary's Hospital Sleep Questionnaire, Oguri-Shirakawa-Azumi Sleep Inventory, and Epworth sleepiness scale, and also objectively evaluated by polysomnography. LTT significantly improved subjective sleep quality indicated by depth of sleep (p quality (p improve subjective and objective sleep quality in patients with HF. LTT can be a complimentary therapy to improve sleep quality in these patients.

Next generation thermal imaging

International Nuclear Information System (INIS)

Marche, P.P.

1988-01-01

The best design of high performance thermal imagers for the 1990s will use horizontal quasi-linear arrays with focal plane processing associated with a simple vertical mechanical scanner. These imagers will have performance that is greatly improved compared to that of present-day devices (50 to 100 percent range and resolution improvement). 5 references

Tissue Damage, Temperature, and pH Induced by Different Electrode Arrays on Potato Pieces (Solanum tuberosum L.

Directory of Open Access Journals (Sweden)

Maraelys Morales González

2018-04-01

Full Text Available One of the most challenging problems of electrochemical therapy is the design and selection of suitable electrode array for cancer. The aim is to determine how two-dimensional spatial patterns of tissue damage, temperature, and pH induced in pieces of potato (Solanum tuberosum L., var. Mondial depend on electrode array with circular, elliptical, parabolic, and hyperbolic shape. The results show the similarity between the shapes of spatial patterns of tissue damage and electric field intensity, which, like temperature and pH take the same shape of electrode array. The adequate selection of suitable electrodes array requires an integrated analysis that involves, in a unified way, relevant information about the electrochemical process, which is essential to perform more efficiently way the therapeutic planning and the personalized therapy for patients with a cancerous tumor.

Towards Development of Microcalorimeter Arrays of Mo/Au Transition-Edge Sensors with Bismuth Absorbers

Science.gov (United States)

Tralshawala, Nilesh; Brekosky, Regis; Figueroa-Feliciano, Enectali; Li, Mary; Stahle, Carl; Stahle, Caroline

2000-01-01

We report on our progress towards the development of arrays of X-ray microcalorimeters as candidates for the high resolution x-ray spectrometer on the Constellation-X mission. The microcalorimeter arrays (30 x 30) with appropriate pixel sizes (0.25 mm. x 0.25 mm) and high packing fractions (greater than 96%) are being developed. Each individual pixel has a 10 micron thick Bi X-ray absorber that is shaped like a mushroom to increase the packing fraction, and a Mo/Au proximity effect superconducting transition edge sensor (TES). These are deposited on a 0.25 or 0.5 micron thick silicon nitride membrane with slits to provide a controllable weak thermal link to the sink temperature. Studies are underway to model, test and optimize the TES pixel uniformity, critical current, heat capacity and the membrane thermal conductance in the array structure. Fabrication issues and procedures, and results of our efforts based on these optimizations will be provided.

Mechanical Development of a Very Non-Standard Patch Array Antenna for Extreme Environments

Science.gov (United States)

Hughes, Richard; Chamberlain, Neil; Jakoboski, Julie; Petkov, Mihail

2012-01-01

This paper describes the mechanical development of patch antenna arrays for the Juno mission. The patch arrays are part of a six-frequency microwave radiometer instrument that will be used to measure thermal emissions from Jupiter. The very harsh environmental conditions in Jupiter orbit, as well as a demanding launch environment, resulted in a design that departs radically from conventional printed circuit patch antennas. The paper discusses the development and qualification of the Juno patch array antennas, with emphasis on the materials approach that was devised to mitigate the effects of electron charging in Jupiter orbit.

Spacing optimization of high power LED arrays for solid state lighting

Energy Technology Data Exchange (ETDEWEB)

Chan, Y. Sing; Lee, S. W. Ricky, E-mail: rickylee@ust.hk [Electronic Packaging Laboratory, Center for Advanced Microsystems Packaging, Hong Kong University of Science and Technology (Hong Kong)

2011-01-15

This paper provides an analytical approach to determine the optimum pitch by utilizing a thermal resistance network, under the assumption of constant luminous efficiency. This work allows an LED array design which is mounted on a printed circuit board (PCB) attached with a heat sink subject to the natural convection cooling. Being validated by finite element (FE) models, the current approach can be shown as an effective method for the determination of optimal component spacing in an LED array assembly for SSL. (semiconductor devices)

Thermal properties of carbon inverse opal photonic crystals

International Nuclear Information System (INIS)

Aliev, Ali E.; Lee, Sergey B.; Baughman, Ray H.; Zakhidov, Anvar A.

2007-01-01

The thermal conductivity of thin-wall glassy carbon and graphitic carbon inverse opals, fabricated by templating of silica opal has been measured in the temperature range 10-400 K using transient pulse method. The heat flow through 100 A-thick layers of graphite sheets tiled on spherical surfaces of empty overlapping spheres arrayed in face-centered-cubic lattices has been analyzed in term of anisotropy factor. Taking into account high anisotropy factor in graphite, γ=342, we found that the thermal conductivity of inverse opal prepared by chemical vapor deposition infiltration is limited by heat flow across the graphitic layers in bottleneck, κ-perpendicular =3.95 W/m K. The electronic contribution to the thermal conductivity, κ e(300K) =3.7x10 -3 W/m K is negligible comparing to the measured value, κ (300K) =0.33 W/m K. The obtained phonon mean free path, l=90 nm is comparable with the graphite segments between hexagonal array of interconnections

Realization of cantilever arrays for parallel proximity imaging

International Nuclear Information System (INIS)

Sarov, Y; Ivanov, Tz; Frank, A; Zoellner, J-P; Nikolov, N; Rangelow, I W

2010-01-01

This paper reports on the fabrication and characterisation of self-actuating, and self-sensing cantilever arrays for large-scale parallel surface scanning. Each cantilever is integrated with a sharp silicon tip, a thermal-driven bimorph actuator, and a piezoresistive deflection sensor. Thus, the tip to the sample distance can be controlled individually for each cantilever. A radius of the tips below 10 nm is obtained, which enables nanometre in-plane surface imaging by Angstrom resolution in vertical direction. The fabricated cantilever probe arrays are also applicable for large-area manipulation, sub-10 nm metrology, bottom-up synthesis, high-speed gas analysis, for different bio-applications like recognition of DNA, RNA, or various biomarkers of a single disease, etc.

Thermal modelling using discrete vasculature for thermal therapy: A review

NARCIS (Netherlands)

Kok, H. Petra; Gellermann, Johanna; van den Berg, Cornelis A. T.; Stauffer, Paul R.; Hand, Jeffrey W.; Crezee, Johannes

2013-01-01

Reliable temperature information during clinical hyperthermia and thermal ablation is essential for adequate treatment control, but conventional temperature measurements do not provide 3D temperature information. Treatment planning is a very useful tool to improve treatment quality, and substantial

Fabrication of microlens arrays using a CO2-assisted embossing technique

International Nuclear Information System (INIS)

Huang, Tzu-Chien; Chan, Bin-Da; Ciou, Jyun-Kai; Yang, Sen-Yeu

2009-01-01

This paper reports a method to fabricate microlens arrays with a low processing temperature and a low pressure. The method is based on embossing a softened polymeric substrate over a mold with micro-hole arrays. Due to the effect of capillary and surface tension, microlens arrays can be formed. The embossing medium is CO 2 gas, which supplies a uniform pressing pressure so that large-area microlens arrays can be fabricated. CO 2 gas also acts as a solvent to plasticize the polymer substrates. With the special dissolving ability and isotropic pressing capacity of CO 2 gas, microlens arrays can be fabricated at a low temperature (lower than T g ) and free of thermal-induced residual stress. Such a combined mechanism of dissolving and embossing with CO 2 gas makes the fabrication of microlens arrays direct with complex processes, and is more compatible for optical usage. In the study, it is also found that the sag height of microlens changes when different CO 2 dissolving pressure and time are used. This makes it easy to fabricate microlens arrays of different geometries without using different molds. The quality, uniformity and optical property of the fabricated microlens arrays have been verified with measurements of the dimensions, surface smoothness, focal length, transmittance and light intensity through the fabricated microlens arrays

Thermal Cycle Reliability and Failure Mechanisms of CCGA and PBGA Assemblies with and without Corner Staking

Science.gov (United States)

Ghaffarian, Reza

2008-01-01

Area array packages (AAPs) with 1.27 mm pitch have been the packages of choice for commercial applications; they are now starting to be implemented for use in military and aerospace applications. Thermal cycling characteristics of plastic ball grid array (PBGA) and chip scale package assemblies, because of their wide usage for commercial applications, have been extensively reported on in literature. Thermal cycling represents the on-off environmental condition for most electronic products and therefore is a key factor that defines reliability.However, very limited data is available for thermal cycling behavior of ceramic packages commonly used for the aerospace applications. For high reliability applications, numerous AAPs are available with an identical design pattern both in ceramic and plastic packages. This paper compares assembly reliability of ceramic and plastic packages with the identical inputs/outputs(I/Os) and pattern. The ceramic package was in the form of ceramic column grid array (CCGA) with 560 I/Os peripheral array with the identical pad design as its plastic counterpart.

A study for soundness of turbine blade root using ultrasonic and phased array

International Nuclear Information System (INIS)

Gil, Doo Song; Park, Sang Ki; Cho, Yong Sang; Lee, Sang Gug; Huh, Kuang Bum

2003-01-01

Power plant is consisted of many component parts for the generation of the electricity and occasionally, turbine equipment may be caused in break-down because of the damage of the blade root. Phased array ultrasonic testing system has become available for power industry. This research describes the characteristics of phased array ultrasonic testing signal for various type of blade roots in thermal power plant turbines. This application of Phased array ultrasonic testing system has been promoted mainly to save inspection time and labor cost of turbine inspection. The characteristic of phased array ultrasonic testing signal for power plant component in very simple to understand but to difficult for perform the inspection. This paper is focused on the safety of the turbine equipment by the ultrasonic measurement and phased array analysis. As a result of the test through ultrasonic and phased array method, we have concluded that the main damage in these turbine blade roots parts could be generated by the concentrated stress and centrifugal force.

Gold nanoparticle array formation on dimpled Ta templates using pulsed laser-induced thin film dewetting.

Science.gov (United States)

El-Sayed, Hany A; Horwood, Corie A; Owusu-Ansah, Ebenezer; Shi, Yujun J; Birss, Viola I

2015-04-28

Here we show that pulsed laser-induced dewetting (PLiD) of a thin Au metallic film on a nano-scale ordered dimpled tantalum (DT) surface results in the formation of a high quality Au nanoparticle (NP) array. In contrast to thermal dewetting, PLiD does not result in deformation of the substrate, even when the Au film is heated to above its melting point. PLiD causes local heating of only the metal film and thus thermal oxidation of the Ta substrate can be avoided, also because of the high vacuum (low pO2) environment employed. Therefore, this technique can potentially be used to fabricate NP arrays composed of high melting point metals, such as Pt, not previously possible using conventional thermal annealing methods. We also show that the Au NPs formed by PLiD are more spherical in shape than those formed by thermal dewetting, likely demonstrating a different dewetting mechanism in the two cases. As the metallic NPs formed on DT templates are electrochemically addressable, a longer-term objective of this work is to determine the effect of NP size and shape (formed by laser vs. thermal dewetting) on their electrocatalytic properties.

Modeling energy production of solar thermal systems and wind turbines for installation at corn ethanol plants

Science.gov (United States)

Ehrke, Elizabeth

Nearly every aspect of human existence relies on energy in some way. Most of this energy is currently derived from fossil fuel resources. Increasing energy demands coupled with environmental and national security concerns have facilitated the move towards renewable energy sources. Biofuels like corn ethanol are one of the ways the U.S. has significantly reduced petroleum consumption. However, the large energy requirement of corn ethanol limits the net benefit of the fuel. Using renewable energy sources to produce ethanol can greatly improve its economic and environmental benefits. The main purpose of this study was to model the useful energy received from a solar thermal array and a wind turbine at various locations to determine the feasibility of applying these technologies at ethanol plants around the country. The model calculates thermal energy received from a solar collector array and electricity generated by a wind turbine utilizing various input data to characterize the equipment. Project cost and energy rate inputs are used to evaluate the profitability of the solar array or wind turbine. The current state of the wind and solar markets were examined to give an accurate representation of the economics of each industry. Eighteen ethanol plant locations were evaluated for the viability of a solar thermal array and/or wind turbine. All ethanol plant locations have long payback periods for solar thermal arrays, but high natural gas prices significantly reduce this timeframe. Government incentives will be necessary for the economic feasibility of solar thermal arrays. Wind turbines can be very profitable for ethanol plants in the Midwest due to large wind resources. The profitability of wind power is sensitive to regional energy prices. However, government incentives for wind power do not significantly change the economic feasibility of a wind turbine. This model can be used by current or future ethanol facilities to investigate or begin the planning process for a

Thermal tomography imaging in photonic traditional Chinese medicine information therapy with holistic effect for health whole nursing.

Science.gov (United States)

Ye, Binggang; Guo, Zhouyi; Huang, Hanchuan; Yang, Xicheng

2015-01-01

A photonic traditional Chinese medicine (TCM) information therapy was developed that has applications in whole health nursing including the prevention and treatment of ischemic cardiovascular and cerebrovascular diseases as well as the conditioning of the subhealth state. This therapy utilizes the beam of a 630 nm LED light to irradiate the oropharynx, while simultaneously employing two beams of 650 nm LED light to irradiate corresponding acupuncture points resulting in a synergistic outcome. This method was named "1 + 2 phototherapy." The principle mechanism of the therapy is a series of photon induced biological effects that are triggered by stimulating the photosensitive tissues of the oropharynx. This tissue includes the oral mucosa, capillaries, lymph nodes, saliva glands, nerves, and Jingluo and is stimulated by light beams of certain photon energy and imitative acupuncture information. Thermal tomography imaging shows that the average temperature of the upper-body was improved significantly after oropharyngeal irradiation under irradiation of "Futu point": the heat radiation of the spine, as well as chest, shoulders, arms, and clavicle, increased under irradiation of "Hoku," whereas the overall average temperature was below the temperature before irradiation. The experiment indicates that this therapy can promote blood circulation, regulate varied physiological parameters, and have holistic effects in whole health nursing.

Large-area high-power VCSEL pump arrays optimized for high-energy lasers

Science.gov (United States)

Wang, Chad; Geske, Jonathan; Garrett, Henry; Cardellino, Terri; Talantov, Fedor; Berdin, Glen; Millenheft, David; Renner, Daniel; Klemer, Daniel

2012-06-01

Practical, large-area, high-power diode pumps for one micron (Nd, Yb) as well as eye-safer wavelengths (Er, Tm, Ho) are critical to the success of any high energy diode pumped solid state laser. Diode efficiency, brightness, availability and cost will determine how realizable a fielded high energy diode pumped solid state laser will be. 2-D Vertical-Cavity Surface-Emitting Laser (VCSEL) arrays are uniquely positioned to meet these requirements because of their unique properties, such as low divergence circular output beams, reduced wavelength drift with temperature, scalability to large 2-D arrays through low-cost and high-volume semiconductor photolithographic processes, high reliability, no catastrophic optical damage failure, and radiation and vacuum operation tolerance. Data will be presented on the status of FLIR-EOC's VCSEL pump arrays. Analysis of the key aspects of electrical, thermal and mechanical design that are critical to the design of a VCSEL pump array to achieve high power efficient array performance will be presented.

A general melt-injection-decomposition route to oriented metal oxide nanowire arrays

Science.gov (United States)

Han, Dongqiang; Zhang, Xinwei; Hua, Zhenghe; Yang, Shaoguang

2016-12-01

In this manuscript, a general melt-injection-decomposition (MID) route has been proposed and realized for the fabrication of oriented metal oxide nanowire arrays. Nitrate was used as the starting materials, which was injected into the nanopores of the anodic aluminum oxide (AAO) membrane through the capillarity action in its liquid state. At higher temperature, the nitrate decomposed into corresponding metal oxide within the nanopores of the AAO membrane. Oriented metal oxide nanowire arrays were formed within the AAO membrane as a result of the confinement of the nanopores. Four kinds of metal oxide (CuO, Mn2O3, Co3O4 and Cr2O3) nanowire arrays are presented here as examples fabricated by this newly developed process. X-ray diffraction, scanning electron microscopy and transmission electron microscopy studies showed clear evidence of the formations of the oriented metal oxide nanowire arrays. Formation mechanism of the metal oxide nanowire arrays is discussed based on the Thermogravimetry and Differential Thermal Analysis measurement results.

Microcoil Spring Interconnects for Ceramic Grid Array Integrated Circuits

Science.gov (United States)

Strickland, S. M.; Hester, J. D.; Gowan, A. K.; Montgomery, R. K.; Geist, D. L.; Blanche, J. F.; McGuire, G. D.; Nash, T. S.

2011-01-01

As integrated circuit miniaturization trends continue, they drive the need for smaller higher input/output (I/O) packages. Hermetically sealed ceramic area array parts are the package of choice by the space community for high reliability space flight electronic hardware. Unfortunately, the coefficient of thermal expansion mismatch between the ceramic area array package and the epoxy glass printed wiring board limits the life of the interconnecting solder joint. This work presents the results of an investigation by Marshall Space Flight Center into a method to increase the life of this second level interconnection by the use of compliant microcoil springs. The design of the spring and its attachment process are presented along with thermal cycling results of microcoil springs (MCS) compared with state-of-the-art ball and column interconnections. Vibration testing has been conducted on MCS and high lead column parts. Radio frequency simulation and measurements have been made and the MCS has been modeled and a stress analysis performed. Thermal cycling and vibration testing have shown MCS interconnects to be significantly more reliable than solder columns. Also, MCS interconnects are less prone to handling damage than solder columns. Future work that includes shock testing, incorporation into a digital signal processor board, and process evaluation of expansion from a 400 I/O device to a device with over 1,100 I/O is identified.

EPOXI Uplink Array Experiment of June 27, 2008

Science.gov (United States)

Vilnrotter, V.; Tsao, P. C.; Lee, D. K.; Cornish, T. P.; Paal, L.; Jamnejad, V.

2008-08-01

Uplink array technology is currently being developed for NASA's Deep Space Network (DSN) to provide greater range and data throughput for future NASA missions, including manned missions to Mars and exploratory missions to the outer planets, the Kuiper Belt, and beyond. The DSN uplink arrays employ N microwave antennas transmitting at 7.2 GHz (X-band) to produce signals that add coherently at the spacecraft, hence providing a power gain of N^2 over a single antenna. This gain can be traded off directly for an N^2 higher data rate at a given distance such as Mars, providing, for example, high-definition video broadcast from Earth to a future human mission, or it can provide a given data rate for commands and software uploads at a distance N times greater than would be possible with a single antenna. The uplink arraying concept has been recently demonstrated using the three operational 34-m antennas of the Apollo Complex at the Goldstone Deep Space Communications Complex in California, which transmitted arrayed signals to the EPOXI spacecraft (an acronym formed from EPOCh and DIXI: Extrasolar Planetary Observation and Characterization and Deep Impact Extended Investigation). Both two-element and three-element uplink arrays were configured, and the theoretical array gains of 6 dB and 9.5 dB, respectively, were demonstrated experimentally. This required initial phasing of the array elements, the generation of accurate frequency predicts to maintain phase from each antenna despite relative velocity components due to Earth rotation and spacecraft trajectory, and monitoring of the ground-system phase for possible drifts caused by thermal effects over the 16-km fiber-optic signal distribution network. This article provides a description of the equipment and techniques used to demonstrate the uplink arraying concept in a relevant operational environment. Data collected from the EPOXI spacecraft are also analyzed to verify array calibration, array gain, and system stability

K-Band Phased Array Developed for Low- Earth-Orbit Satellite Communications

Science.gov (United States)

Anzic, Godfrey

1999-01-01

Future rapid deployment of low- and medium-Earth-orbit satellite constellations that will offer various narrow- to wide-band wireless communications services will require phased-array antennas that feature wide-angle and superagile electronic steering of one or more antenna beams. Antennas, which employ monolithic microwave integrated circuits (MMIC), are perfectly suited for this application. Under a cooperative agreement, an MMIC-based, K-band phased-array antenna is being developed with 50/50 cost sharing by the NASA Lewis Research Center and Raytheon Systems Company. The transmitting array, which will operate at 19 gigahertz (GHz), is a state-of-the-art design that features dual, independent, electronically steerable beam operation ( 42 ), a stand-alone thermal management, and a high-density tile architecture. This array can transmit 622 megabits per second (Mbps) in each beam from Earth orbit to small Earth terminals. The weight of the total array package is expected to be less than 8 lb. The tile integration technology (flip chip MMIC tile) chosen for this project represents a major advancement in phased-array engineering and holds much promise for reducing manufacturing costs.

Anodic Fabrication of Ti-Ni-O Nanotube Arrays on Shape Memory Alloy

Directory of Open Access Journals (Sweden)

Qiang Liu

2014-04-01

Full Text Available Surface modification with oxide nanostructures is one of the efficient ways to improve physical or biomedical properties of shape memory alloys. This work reports a fabrication of highly ordered Ti-Ni-O nanotube arrays on Ti-Ni alloy substrates through pulse anodization in glycerol-based electrolytes. The effects of anodization parameters and the annealing process on the microstructures and surface morphology of Ti-Ni-O were studied using scanning electron microscope and Raman spectroscopy. The electrolyte type greatly affected the formation of nanotube arrays. A formation of anatase phase was found with the Ti-Ni-O nanotube arrays annealed at 450 °C. The oxide nanotubes could be crystallized to rutile phase after annealing treatment at 650 °C. The Ti-Ni-O nanotube arrays demonstrated an excellent thermal stability by keeping their nanotubular structures up to 650 °C.

Laser-based microstructuring of materials surfaces using low-cost microlens arrays

Science.gov (United States)

Nieto, Daniel; Vara, G.; Diez, J. A.; O`Connor, Gerard M.; Arines, Justo; Gómez-Reino, C.; Flores-Arias, M.

2012-03-01

Since frictional interactions in microscopically small components are becoming increasingly important for the development of new products for all modern technology, we present a laser-based technique for micro-patterning surfaces of materials using low-cost microlens arrays. The microlens used were fabricated on soda-lime glass using a laser direct-write technique, followed by a thermal treatment into an oven. By combining laser direct-write and the thermal treatment it was possible to obtain high quality elements using a low cost infrared laser widely implemented in industry which makes this technique attractive in comparison with other more expensive methods. The main advantage of using microlens arrays for micropatterning surfaces is the possibility of fabricating a large number of identical structures simultaneously, leading to a highly efficient process. In order to study the capabilities of the microlens fabricated for microstructuring materials, identical structures and arrays of holes were fabricated over a variety of materials, such us, stainless steel, polymer and ceramic. The minimum diameter of the individual microstructure generated at surface is 5 μm. Different nanosecond lasers operating at Infrared, Green and UV were used. The topography and morphology of the elements obtained were determined using a confocal microscope SENSOFAR 2300 Plμ.

Development of an Electrostatically Clean Solar Array Panel

Science.gov (United States)

Stern, Theodore G.; Krumweide, Duane; Gaddy, Edward; Katz, Ira

2000-01-01

The results of design, analysis, and qualification of an Electrostatically Clean Solar Array (ECSA) panel are described. The objective of the ECSA design is to provide an electrostatic environment that does not interfere with sensitive instruments on scientific spacecraft. The ECSA design uses large, ITO-coated coverglasses that cover multiple solar cells, an aperture grid that covers the intercell areas, stress-relieved interconnects for connecting the aperture grid to the coverglasses, and edge clips to provides an electromagnetically shielded enclosure for the solar array active circuitry. Qualification coupons were fabricated and tested for photovoltaic response, conductivity, and survivability to launch acoustic and thermal cycling environments simulating LEO and GEO missions. The benefits of reducing solar panel interaction with the space environment are also discussed.

Theoretical modelling, experimental studies and clinical simulations of urethral cooling catheters for use during prostate thermal therapy

International Nuclear Information System (INIS)

Davidson, Sean R H; Sherar, Michael D

2003-01-01

Urethral cooling catheters are used to prevent thermal damage to the urethra during thermal therapy of the prostate. Quantification of a catheter's heat transfer characteristics is necessary for prediction of the catheter's influence on the temperature and thermal dose distribution in periurethral tissue. Two cooling catheters with different designs were examined: the Dornier Urowave catheter and a prototype device from BSD Medical Corp. A convection coefficient, h, was used to characterize the cooling ability of each catheter. The value of the convection coefficient (h = 330 W m -2 deg C -1 for the Dornier catheter, h = 160 W m -2 deg C -1 for the BSD device) was obtained by comparing temperatures measured in a tissue-equivalent phantom material to temperatures predicted by a finite element method simulation of the phantom experiments. The coefficient was found to be insensitive to the rate of coolant flow inside the catheter between 40 and 120 ml min -1 . The convection coefficient method for modelling urethral catheters was incorporated into simulations of microwave heating of the prostate. Results from these simulations indicate that the Dornier device is significantly more effective than the BSD catheter at cooling the tissue surrounding the urethra

Neutron detection using a planar array of superheated superconductors

International Nuclear Information System (INIS)

Meagher, G.

1996-01-01

A new thermal neutron detector consisting of an indium/mylar PASS array with a filler of boron powder has been tested successfully. A boron nucleus captures a neutron and the α-particle emitted in this reaction nucleates the transition to the normal state in a neighbouring grain. A PASS with grain radius r=12 μm showed very low response to irradiation by 835 keV γ-rays. The same PASS responded to α-particles with high efficiency, and thermal neutrons were detected with good efficiency and very low background. Thermal neutrons were also counted with an R=25 μm PASS. The use of large granules will allow spatial resolution to a single grain to be obtained and a read-out based on conventional inductive coupling and fast electronics to be utilized. (orig.)

Characterization and evaluation of a flexible MRI receive coil array for radiation therapy MR treatment planning using highly decoupled RF circuits

Science.gov (United States)

McGee, Kiaran P.; Stormont, Robert S.; Lindsay, Scott A.; Taracila, Victor; Savitskij, Dennis; Robb, Fraser; Witte, Robert J.; Kaufmann, Timothy J.; Huston, John, III; Riederer, Stephen J.; Borisch, Eric A.; Rossman, Phillip J.

2018-04-01

The growth in the use of magnetic resonance imaging (MRI) data for radiation therapy (RT) treatment planning has been facilitated by scanner hardware and software advances that have enabled RT patients to be imaged in treatment position while providing morphologic and functional assessment of tumor volumes and surrounding normal tissues. Despite these advances, manufacturers have been slow to develop radiofrequency (RF) coils that closely follow the contour of a RT patient undergoing MR imaging. Instead, relatively large form surface coil arrays have been adapted from diagnostic imaging. These arrays can be challenging to place on, and in general do not conform to the patient’s body habitus, resulting in sub optimal image quality. The purpose of this study is to report on the characterization of a new flexible and highly decoupled RF coil for use in MR imaging of RT patients. Coil performance was evaluated by performing signal-to-noise ratio (SNR) and noise correlation measurements using two coil (SNR) and four coil (noise correlation) element combinations as a function of coil overlap distance and comparing these values to those obtained using conventional coil elements. In vivo testing was performed in both normal volunteers and patients using a four and 16 element RF coil. Phantom experiments demonstrate the highly decoupled nature of the new coil elements when compared to conventional RF coils, while in vivo testing demonstrate that these coils can be integrated into extremely flexible and form fitting substrates that follow the exact contour of the patient. The new coil design addresses limitations imposed by traditional surface coil arrays and have the potential to significantly impact MR imaging for both diagnostic and RT applications.

Transdermal Delivery of siRNA through Microneedle Array

Science.gov (United States)

Deng, Yan; Chen, Jiao; Zhao, Yi; Yan, Xiaohui; Zhang, Li; Choy, Kwongwai; Hu, Jun; Sant, Himanshu J.; Gale, Bruce K.; Tang, Tao

2016-02-01

Successful development of siRNA therapies has significant potential for the treatment of skin conditions (alopecia, allergic skin diseases, hyperpigmentation, psoriasis, skin cancer, pachyonychia congenital) caused by aberrant gene expression. Although hypodermic needles can be used to effectively deliver siRNA through the stratum corneum, the major challenge is that this approach is painful and the effects are restricted to the injection site. Microneedle arrays may represent a better way to deliver siRNAs across the stratum corneum. In this study, we evaluated for the first time the ability of the solid silicon microneedle array for punching holes to deliver cholesterol-modified housekeeping gene (Gapdh) siRNA to the mouse ear skin. Treating the ear with microneedles showed permeation of siRNA in the skin and could reduce Gapdh gene expression up to 66% in the skin without accumulation in the major organs. The results showed that microneedle arrays could effectively deliver siRNA to relevant regions of the skin noninvasively.

Conformal atomic layer deposition of alumina on millimeter tall, vertically-aligned carbon nanotube arrays.

Science.gov (United States)

Stano, Kelly L; Carroll, Murphy; Padbury, Richard; McCord, Marian; Jur, Jesse S; Bradford, Philip D

2014-11-12

Atomic layer deposition (ALD) can be used to coat high aspect ratio and high surface area substrates with conformal and precisely controlled thin films. Vertically aligned arrays of multiwalled carbon nanotubes (MWCNTs) with lengths up to 1.5 mm were conformally coated with alumina from base to tip. The nucleation and growth behaviors of Al2O3 ALD precursors on the MWCNTs were studied as a function of CNT surface chemistry. CNT surfaces were modified through a series of post-treatments including pyrolytic carbon deposition, high temperature thermal annealing, and oxygen plasma functionalization. Conformal coatings were achieved where post-treatments resulted in increased defect density as well as the extent of functionalization, as characterized by X-ray photoelectron spectroscopy and Raman spectroscopy. Using thermogravimetric analysis, it was determined that MWCNTs treated with pyrolytic carbon and plasma functionalization prior to ALD coating were more stable to thermal oxidation than pristine ALD coated samples. Functionalized and ALD coated arrays had a compressive modulus more than two times higher than a pristine array coated for the same number of cycles. Cross-sectional energy dispersive X-ray spectroscopy confirmed that Al2O3 could be uniformly deposited through the entire thickness of the vertically aligned MWCNT array by manipulating sample orientation and mounting techniques. Following the ALD coating, the MWCNT arrays demonstrated hydrophilic wetting behavior and also exhibited foam-like recovery following compressive strain.

Hydrodynamics of single- and two-phase flow in inclined rod arrays

International Nuclear Information System (INIS)

Ebeling-Koning, D.B.; Todreas, N.E.

1983-09-01

Required inputs for thermal-hydraulic codes are constitutive relations for fluid-solid flow resistance, in single-phase flow, and interfacial momentum exchange (relative phase motion), in two-phase flow. An inclined rod array air-water experiment was constructed to study the hydrodynamics of multidimensional porous medium flow in rod arrays. Velocities, pressures, and bubble distributions were measured in square rod arrays of P/d = 1.5, at 0, 30, 45, and 90 degree inclinations to the vertical flow direction. Constitutive models for single-phase flow resistance are reviewed, new comprehensive models developed, and an assessment with previously published and new data made. The principle of superimposing one-dimensional correlations proves successful for turbulent single-phase inclined flow. For bubbly two-phase incline flow a new flow separation phenomena was observed and modeled. A two-region liquid velocity model is developed to explain the experimentally observed phenomena. Fundamental data for bubbles rising in rod arrays were also taken

Thermal Vacuum Integrated System Test at B-2

Science.gov (United States)

Kudlac, Maureen T.; Weaver, Harold F.; Cmar, Mark D.

2012-01-01

The National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC) Plum Brook Station (PBS) Space Propulsion Research Facility, commonly referred to as B-2, is NASA s third largest thermal vacuum facility. It is the largest designed to store and transfer large quantities of liquid hydrogen and liquid oxygen, and is perfectly suited to support developmental testing of chemical propulsion systems as well as fully integrated stages. The facility is also capable of providing thermal-vacuum simulation services to support testing of large lightweight structures, Cryogenic Fluid Management (CFM) systems, electric propulsion test programs, and other In-Space propulsion programs. A recently completed integrated system test demonstrated the refurbished thermal vacuum capabilities of the facility. The test used the modernized data acquisition and control system to monitor the facility during pump down of the vacuum chamber, operation of the liquid nitrogen heat sink (or cold wall) and the infrared lamp array. A vacuum level of 1.3x10(exp -4)Pa (1x10(exp -6)torr) was achieved. The heat sink provided a uniform temperature environment of approximately 77 K (140deg R) along the entire inner surface of the vacuum chamber. The recently rebuilt and modernized infrared lamp array produced a nominal heat flux of 1.4 kW/sq m at a chamber diameter of 6.7 m (22 ft) and along 11 m (36 ft) of the chamber s cylindrical vertical interior. With the lamp array and heat sink operating simultaneously, the thermal systems produced a heat flux pattern simulating radiation to space on one surface and solar exposure on the other surface. The data acquired matched pretest predictions and demonstrated system functionality.

Investigation of illumination efficiency on the LED therapy with different array types

Science.gov (United States)

Chen, Hsi-Chao; Liou, Cheng-Jyun

2009-08-01

Light-emitting diodes (LEDs) are a major discovery in twenty-one century for its advantages including small size, long lifetime, low voltage, high response and good mechanical properties. It is an environment-friendly product and maybe becomes a lighting source in future. In the other way LED lighting also is used for the lighting source of cosmetology. LED phototherapy provided medicine with a new tool capable of delivering light deep into tissues of the body, at wavelengths that are biologically optimal for pain treatment and holistic healing. The illumination efficiency is one of the key indexes for the LED phototherapy. LEDs were arranged on a disk of diameter of 100mm with different array types: a radial, a rhombus, an octagon, and a square. Then the LEDs with view angle of 120 degree were used for the lighting sources. Trace-Pro software was used for the optical simulation. The array types of radial and square were better than those of rhombus and octagon for illumination efficiency. In the mixture efficiency of a radial array was observed by different distances from 1mm to 100mm. However lighting could reach the well mixture after the treatment distance of 30mm by optical simulation. The view angle could reach +/-60 degree at the treatment distance of 50 mm for the LED phototherapy mockup.

Using Low-Frequency Phased Arrays to Detect Cracks in Cast Austenitic Piping Components

International Nuclear Information System (INIS)

Anderson, Michael T.; Cumblidge, Stephen E.; Doctor, Steven R.

2005-01-01

As part of a multi-year program funded by the United States Nuclear Regulatory Commission (US NRC) to address NDE reliability of inservice inspection (ISI) programs, recent studies conducted at the Pacific Northwest National Laboratory (PNNL) in Richland, Washington, have focused on assessing novel NDE approaches for the inspection of coarse-grained, cast stainless steel reactor components. The primary objective of this work is to provide information to the US NRC on the utility, effectiveness and reliability of ultrasonic testing (UT) and eddy current testing (ET) inspection techniques as related to the ISI of primary piping components in pressurized water reactors (PWRs). This paper describes progress, recent developments and early results from an assessment of a portion of this work relating to the ultrasonic low frequency phased array inspection technique. Westinghouse Owner's Group (WOG) cast stainless steel pipe segments with thermal and mechanical fatigue cracks, PNNL samples containing thermal fatigue cracks and several blank vintage specimens having very coarse grains that are representative of early centrifugally cast piping installed in PWRs, are being used for assessing the inspection method. The phased array approach was implemented using an R/D Tech Tomoscan III system operating at 1.0 MHz and 500 kHz, providing composite volumetric images of the samples. Several dual, transmit-receive, custom designed low-frequency arrays are employed in laboratory trials. Results from laboratory studies for assessing detection of thermal and mechanical fatigue cracks in cast stainless steel piping welds are discussed

BASIMO - Borehole Heat Exchanger Array Simulation and Optimization Tool

Science.gov (United States)

Schulte, Daniel O.; Bastian, Welsch; Wolfram, Rühaak; Kristian, Bär; Ingo, Sass

2017-04-01

Arrays of borehole heat exchangers are an increasingly popular source for renewable energy. Furthermore, they can serve as borehole thermal energy storage (BTES) systems for seasonally fluctuating heat sources like solar thermal energy or district heating grids. The high temperature level of these heat sources prohibits the use of the shallow subsurface for environmental reasons. Therefore, deeper reservoirs have to be accessed instead. The increased depth of the systems results in high investment costs and has hindered the implementation of this technology until now. Therefore, research of medium deep BTES systems relies on numerical simulation models. Current simulation tools cannot - or only to some extent - describe key features like partly insulated boreholes unless they run fully discretized models of the borehole heat exchangers. However, fully discretized models often come at a high computational cost, especially for large arrays of borehole heat exchangers. We give an update on the development of BASIMO: a tool, which uses one dimensional thermal resistance and capacity models for the borehole heat exchangers coupled with a numerical finite element model for the subsurface heat transport in a dual-continuum approach. An unstructured tetrahedral mesh bypasses the limitations of structured grids for borehole path geometries, while the thermal resistance and capacity model is improved to account for borehole heat exchanger properties changing with depth. Thereby, partly insulated boreholes can be considered in the model. Furthermore, BASIMO can be used to improve the design of BTES systems: the tool allows for automated parameter variations and is readily coupled to other code like mathematical optimization algorithms. Optimization can be used to determine the required minimum system size or to increase the system performance.

Subharmonic structure of Shapiro steps in frustrated superconducting arrays

International Nuclear Information System (INIS)

Kim, S.; Kim, B.J.; Choi, M.Y.

1995-01-01

Two-dimensional superconducting arrays with combined direct and alternating applied currents are studied both analytically and numerically. In particular, we investigate in detail current-voltage characteristics of a square array with 1/2 flux quantum per plaquette and triangular arrays with 1/2 and 1/4 flux quantum per plaquette. At zero temperature reduced equations of motion are obtained through the use of the translational symmetry present in the systems. The reduced equations lead to a series of subharmonic steps in addition to the standard integer and fractional giant Shapiro steps, producing devil's staircase structure. This devil's staircase structure reflects the existence of dynamically generated states in addition to the states originating from degenerate ground states in equilibrium. Widths of the subharmonic steps as functions of the amplitudes of alternating currents display Bessel-function-type behavior. We also present results of extensive numerical simulations, which indeed reveal the subharmonic steps together with their stability against small thermal fluctuations. Implications for topological invariance are also discussed

A study for soundness of turbine blade root using ultrasonic and phased array

International Nuclear Information System (INIS)

Gil, Doo Song; Park, Sang Ki; Cho, Yong Sang; Lee, Sang Gug; Huh, Kuang Bum

2003-01-01

Power plant is consisted of many component parts for the generation of the electricity, and occasionally, turbine equipment may be caused in break-down because of the damage of the blade root. Phased array ultrasonic testing system has become available for practical application in complicated geometry such as turbine blade root, tenon, disc in power industry. This research describes the characteristics of phased array ultrasonic testing signal for various type of blade roots in thermal Power Plant turbines. This application of Phased array ultrasonic testing system has been promoted mainly to save inspection time and labor cost of turbine inspection. The characteristic of phased array ultrasonic testing signal for power plant component in very simple to understand but to difficult for perform the inspection. This paper is focused on the safety of the turbine equipment by the ultrasonic measurement and phased array analysis. As a result of the test through ultrasonic and phased array method, we have concluded that the main damage in these turbine blade root parts could be generated by the concentrated stress and centrifugal force.

Reduction of thermal conductivity in phononic nanomesh structures.

Science.gov (United States)

Yu, Jen-Kan; Mitrovic, Slobodan; Tham, Douglas; Varghese, Joseph; Heath, James R

2010-10-01

Controlling the thermal conductivity of a material independently of its electrical conductivity continues to be a goal for researchers working on thermoelectric materials for use in energy applications and in the cooling of integrated circuits. In principle, the thermal conductivity κ and the electrical conductivity σ may be independently optimized in semiconducting nanostructures because different length scales are associated with phonons (which carry heat) and electric charges (which carry current). Phonons are scattered at surfaces and interfaces, so κ generally decreases as the surface-to-volume ratio increases. In contrast, σ is less sensitive to a decrease in nanostructure size, although at sufficiently small sizes it will degrade through the scattering of charge carriers at interfaces. Here, we demonstrate an approach to independently controlling κ based on altering the phonon band structure of a semiconductor thin film through the formation of a phononic nanomesh film. These films are patterned with periodic spacings that are comparable to, or shorter than, the phonon mean free path. The nanomesh structure exhibits a substantially lower thermal conductivity than an equivalently prepared array of silicon nanowires, even though this array has a significantly higher surface-to-volume ratio. Bulk-like electrical conductivity is preserved. We suggest that this development is a step towards a coherent mechanism for lowering thermal conductivity.

Large-area gold nanohole arrays fabricated by one-step method for surface plasmon resonance biochemical sensing.

Science.gov (United States)

Qi, Huijie; Niu, Lihong; Zhang, Jie; Chen, Jian; Wang, Shujie; Yang, Jingjing; Guo, Siyi; Lawson, Tom; Shi, Bingyang; Song, Chunpeng

2018-04-01

Surface plasmon resonance (SPR) nanosensors based on metallic nanohole arrays have been widely reported to detect binding interactions in biological specimens. A simple and effective method for constructing nanoscale arrays is essential for the development of SPR nanosensors. In this work, we report a one-step method to fabricate nanohole arrays by thermal nanoimprinting in the matrix of IPS (Intermediate Polymer Stamp). No additional etching process or supporting substrate is required. The preparation process is simple, time-saving and compatible for roll-to-roll process, potentially allowing mass production. Moreover, the nanohole arrays were integrated into detection platform as SPR sensors to investigate different types of biological binding interactions. The results demonstrate that our one-step method can be used to efficiently fabricate large-area and uniform nanohole arrays for biochemical sensing.

A study on the crack inspection signal characteristics for power plant components by phased array UT

International Nuclear Information System (INIS)

Cho, Yong Sang; Lim, Sang Gyu; Kil, Du Song

2001-01-01

Phased array ultrasonic testing system has become available for practical application in complicated geometry such as turbine blade root, tenon, disc in power industry. This research describes the characteristics of phased array UT signal for various type of blade roots in thermal Power Plant turbines. This application of Phased array ultrasonic testing system has been promoted mainly to save inspection time and labor cost of turbine inspection. The characteristic of phase array UT signal for power plant component is very simple to understand but to difficult for perform the inspection. Since our sophisticated inspection technique and systems are essential for the inspection of steam turbine blade roots that require high reliability, we intend to develop new technology and improve phased array technique based on the wide and much experience for the inspection of turbine components.

Diode temperature sensor array for measuring and controlling micro scale surface temperature

International Nuclear Information System (INIS)

Han, Il Young; Kim, Sung Jin

2004-01-01

The needs of micro scale thermal detecting technique are increasing in biology and chemical industry. For example, thermal finger print, Micro PCR(Polymer Chain Reaction), TAS and so on. To satisfy these needs, we developed a DTSA(Diode Temperature Sensor Array) for detecting and controlling the temperature on small surface. The DTSA is fabricated by using VLSI technique. It consists of 32 array of diodes(1,024 diodes) for temperature detection and 8 heaters for temperature control on a 8mm surface area. The working principle of temperature detection is that the forward voltage drop across a silicon diode is approximately proportional to the inverse of the absolute temperature of diode. And eight heaters (1K) made of poly-silicon are added onto a silicon wafer and controlled individually to maintain a uniform temperature distribution across the DTSA. Flip chip packaging used for easy connection of the DTSA. The circuitry for scanning and controlling DTSA are also developed

VERY LARGE ARRAY OBSERVATIONS OF DG TAU'S RADIO JET: A HIGHLY COLLIMATED THERMAL OUTFLOW

Energy Technology Data Exchange (ETDEWEB)

Lynch, C.; Mutel, R. L.; Gayley, K. G. [Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52240 (United States); Guedel, M. [Department of Astrophysics, University of Vienna, A-1180 Vienna (Austria); Ray, T. [Astronomy and Astrophysics Section, Dublin Institute for Advanced Studies, 31 Fitzwilliam Place, Dublin 2 (Ireland); Skinner, S. L. [Center for Astrophysics and Space Astronomy, University of Colorado, Boulder, CO 80309 (United States); Schneider, P. C. [Hamburger Sternwarte, Gojenbergsweg 112, D-21029 Hamburg (Germany)

2013-03-20

The active young protostar DG Tau has an extended jet that has been well studied at radio, optical, and X-ray wavelengths. We report sensitive new Very Large Array (VLA) full-polarization observations of the core and jet between 5 GHz and 8 GHz. Our high angular resolution observation at 8 GHz clearly shows an unpolarized inner jet with a size of 42 AU (0.''35) extending along a position angle similar to the optical-X ray outer jet. Using our nearly coeval 2012 VLA observations, we find a spectral index {alpha} = +0.46 {+-} 0.05, which combined with the lack of polarization is consistent with bremsstrahlung (free-free) emission, with no evidence for a non-thermal coronal component. By identifying the end of the radio jet as the optical depth unity surface, and calculating the resulting emission measure, we find that our radio results are in agreement with previous optical line studies of electron density and consequent mass-loss rate. We also detect a weak radio knot at 5 GHz located 7'' from the base of the jet, coincident with the inner radio knot detected by Rodriguez et al. in 2009 but at lower surface brightness. We interpret this as due to expansion of post-shock ionized gas in the three years between observations.

Highly directional transurethral ultrasound applicators with rotational control for MRI-guided prostatic thermal therapy

Energy Technology Data Exchange (ETDEWEB)

Ross, Anthony B [Thermal Therapy Research Group, UCSF Radiation Oncology, San Francisco, CA (United States); Diederich, Chris J [Thermal Therapy Research Group, UCSF Radiation Oncology, San Francisco, CA (United States); Nau, William H [Thermal Therapy Research Group, UCSF Radiation Oncology, San Francisco, CA (United States); Gill, Harcharan [Department of Urology, Stanford University, Stanford, CA (United States); Bouley, Donna M [Department of Comparative Medicine, Stanford University, Stanford, CA (United States); Daniel, Bruce [Department of Radiology, Stanford University, Stanford, CA (United States); Rieke, Viola [Department of Radiology, Stanford University, Stanford, CA (United States); Butts, R Kim [Department of Radiology, Stanford University, Stanford, CA (United States); Sommer, Graham [Department of Radiology, Stanford University, Stanford, CA (United States)

2004-01-21

Transurethral ultrasound applicators with highly directional energy deposition and rotational control were investigated for precise treatment of benign prostatic hyperplasia (BPH) and adenocarcinoma of the prostate (CaP). Two types of catheter-based applicators were fabricated, using either sectored tubular (3.5 mm OD x 10 mm) or planar transducers (3.5 mm x 10 mm). They were constructed to be MRI compatible, minimally invasive and allow for manual rotation of the transducer array within a 10 mm cooling balloon. In vivo evaluations of the applicators were performed in canine prostates (n 3) using MRI guidance (0.5 T interventional magnet). MR temperature imaging (MRTI) utilizing the proton resonance frequency shift method was used to acquire multiple-slice temperature overlays in real time for monitoring and guiding the thermal treatments. Post-treatment T1-weighted contrast-enhanced imaging and triphenyl tetrazolium chloride stained tissue sections were used to define regions of tissue coagulation. Single sonications with the tubular applicator ) produced coagulated zones covering a wedge of the prostate extending from 1-2 mm outside the urethra to the outer boundary of the gland (16 mm radial coagulation). Single sonications with the planar applicator (15-20 W, 10 min, {approx}8 MHz) generated thermal lesions of {approx}30 extending to the prostate boundary. Multiple sequential sonications (sweeping) of a planar applicator (12 W with eight rotations of 30 each) demonstrated controllable coagulation of a 270 contiguous section of the prostate extending to the capsule boundary. The feasibility of using highly directional transurethral ultrasound applicators with rotational capabilities to selectively coagulate regions of the prostate while monitoring and controlling the treatments with MRTI was demonstrated in this study.

Nanoscale thermal transport. II. 2003–2012

OpenAIRE

Cahill, David G.; Braun, Paul V.; Chen, Gang; Clarke, David R.; Fan, Shanhui; Goodson, Kenneth E.; Keblinski, Pawel; King, William P.; Mahan, Gerald D.; Majumdar, Arun; Maris, Humphrey J.; Phillpot, Simon R.; Pop, Eric; Shi, Li

2013-01-01

A diverse spectrum of technology drivers such as improved thermal barriers, higher efficiency thermoelectric energy conversion, phase-change memory, heat-assisted magnetic recording, thermal management of nanoscale electronics, and nanoparticles for thermal medical therapies are motivating studies of the applied physics of thermal transport at the nanoscale. This review emphasizes developments in experiment, theory, and computation in the past ten years and summarizes the present status of th...

Observation of intact desorption ionization of peptide molecules from arrays of tungsten oxide nanowires by laser irradiation

Energy Technology Data Exchange (ETDEWEB)

Han, Sang Yun [Dept. of Nanochemistry, Gachon University, Seongnam (Korea, Republic of)

2015-08-15

Length-controlled WO{sub 3} surface nanowires with a 50 nm diameter were prepared by utilizing anodic Al{sub 2}O{sub 3} templates. Careful control of the fabrication process yielded a set of length-controlled nanowire arrays (Figure 1). The lengths of the nanowires covered a range of 60–250 nm. Typically, a 0.5-μL drop of a sample solution in 10% MeOH that contained 2 pmol of sample was pipetted directly onto the nanowire chips, which were dried under ambient conditions. We report the observation of intact LDI of thermally labile peptides from WO{sub 3} nanowire arrays, which have never been reported for any other metal oxide nanowire arrays. As metal oxides are thermally stable and useful in many applications, and fabrication of various nanostructures are well established, we suggest that the nanostructured surfaces of metal oxides are promising for LDI and thus worthy of further investigations.

Safety of Laser Interstitial Thermal Therapy in Patients With Pacemakers.

Science.gov (United States)

Grewal, Sanjeet S; Gorny, Krzysztof R; Favazza, Christopher P; Watson, Robert E; Kaufmann, Timothy J; Van Gompel, Jamie J

2018-02-10

Laser interstitial thermal therapy (LiTT) has increasingly been used as a treatment option for medically refractory epilepsy, tumors, and radiation necrosis. The use of LiTT requires intraoperative magnetic resonance (MR) thermography. This can become an issue in patients with other implanted therapeutic devices such as pacemakers and vagal nerve stimulators due to concerns regarding increases in the specific absorption rate (SAR). This is a technical case report demonstrating a successfully and safely performed LiTT in a 1.5-T magnetic resonance imaging (MRI) in a patient with a pacemaker for mesial temporal sclerosis. An 83-yr-old gentleman who had an implanted cardiac pacemaker presented with medically intractable epilepsy and was confirmed to have mesial temporal sclerosis on imaging. Video electroencephalography demonstrated concordant ipsilateral seizures and semiology. He underwent LiTT for ablation of the mesial temporal lobe. This was performed with the below described protocol with a cardiology nurse monitoring the patient's cardiac condition and a physicist monitoring SAR, and MR imaging quality without any adverse events. This study reports on a protocol of cardiac and MR SAR to safely perform MR-guided LiTT in the setting of traditional pacemakers in patients who are not pacemaker dependent. Copyright © 2018 by the Congress of Neurological Surgeons

Thermalism in Argentina. Alternative or complementary dermatologic therapy.

Science.gov (United States)

Ubogui, J; Stengel, F M; Kien, M C; Sevinsky, L; Rodríguez Lupo, L

1998-11-01

Our study took place in the region of the Copahue Volcano in the Andes Mountain range, 1900 m above sea level. Fifty-five patients who came to the Copahue Thermal Basin Complex (Neuquén, Argentina) for treatment of psoriasis vulgaris were clinically evaluated for participation in this study. Thermal products--waters, mud, and/or algae--were the only therapeutic agents used, except for bland emollients for xerosis. Treatment for brief periods (10 +/- 3 days) resulted in notable improvement.

Thermal neutron flux distribution in ET-RR-2 reactor thermal column

Directory of Open Access Journals (Sweden)

Imam Mahmoud M.

2002-01-01

Full Text Available The thermal column in the ET-RR-2 reactor is intended to promote a thermal neutron field of high intensity and purity to be used for following tasks: (a to provide a thermal neutron flux in the neutron transmutation silicon doping, (b to provide a thermal flux in the neutron activation analysis position, and (c to provide a thermal neutron flux of high intensity to the head of one of the beam tubes leading to the room specified for boron thermal neutron capture therapy. It was, therefore, necessary to determine the thermal neutron flux at above mentioned positions. In the present work, the neutron flux in the ET-RR-2 reactor system was calculated by applying the three dimensional diffusion depletion code TRITON. According to these calculations, the reactor system is composed of the core, surrounding external irradiation grid, beryllium block, thermal column and the water reflector in the reactor tank next to the tank wall. As a result of these calculations, the thermal neutron fluxes within the thermal column and at irradiation positions within the thermal column were obtained. Apart from this, the burn up results for the start up core calculated according to the TRITION code were compared with those given by the reactor designer.

Focal plane array with modular pixel array components for scalability

Science.gov (United States)

Kay, Randolph R; Campbell, David V; Shinde, Subhash L; Rienstra, Jeffrey L; Serkland, Darwin K; Holmes, Michael L

2014-12-09

A modular, scalable focal plane array is provided as an array of integrated circuit dice, wherein each die includes a given amount of modular pixel array circuitry. The array of dice effectively multiplies the amount of modular pixel array circuitry to produce a larger pixel array without increasing die size. Desired pixel pitch across the enlarged pixel array is preserved by forming die stacks with each pixel array circuitry die stacked on a separate die that contains the corresponding signal processing circuitry. Techniques for die stack interconnections and die stack placement are implemented to ensure that the desired pixel pitch is preserved across the enlarged pixel array.

Timed arrays wideband and time varying antenna arrays

CERN Document Server

Haupt, Randy L

2015-01-01

Introduces timed arrays and design approaches to meet the new high performance standards The author concentrates on any aspect of an antenna array that must be viewed from a time perspective. The first chapters briefly introduce antenna arrays and explain the difference between phased and timed arrays. Since timed arrays are designed for realistic time-varying signals and scenarios, the book also reviews wideband signals, baseband and passband RF signals, polarization and signal bandwidth. Other topics covered include time domain, mutual coupling, wideband elements, and dispersion. The auth

Compact, semi-passive beam steering prism array for solar concentrators.

Science.gov (United States)

Zheng, Cheng; Li, Qiyuan; Rosengarten, Gary; Hawkes, Evatt; Taylor, Robert A

2017-05-10

In order to maximize solar energy utilization in a limited space (e.g., rooftops), solar collectors should track the sun. As an alternative to rotational tracking systems, this paper presents a compact, semi-passive beam steering prism array which has been designed, analyzed, and tested for solar applications. The proposed prism array enables a linear concentrator system to remain stationary so that it can integrate with a variety of different solar concentrators, and which should be particularly useful for systems which require a low profile (namely rooftop-mounted systems). A case study of this prism array working within a specific rooftop solar collector demonstrates that it can boost the average daily optical efficiency of the collector by 32.7% and expand its effective working time from 6 h to 7.33 h. Overall, the proposed design provides an alternative way to "follow" the sun for a wide range of solar thermal and photovoltaic concentrator systems.

Development of a spherically focused phased array transducer for ultrasonic image-guided hyperthermia.

Science.gov (United States)

Liu, Jingfei; Foiret, Josquin; Stephens, Douglas N; Le Baron, Olivier; Ferrara, Katherine W

2016-07-21

A 1.5 MHz prolate spheroidal therapeutic array with 128 circular elements was designed to accommodate standard imaging arrays for ultrasonic image-guided hyperthermia. The implementation of this dual-array system integrates real-time therapeutic and imaging functions with a single ultrasound system (Vantage 256, Verasonics). To facilitate applications involving small animal imaging and therapy the array was designed to have a beam depth of field smaller than 3.5 mm and to electronically steer over distances greater than 1 cm in both the axial and lateral directions. In order to achieve the required f number of 0.69, 1-3 piezocomposite modules were mated within the transducer housing. The performance of the prototype array was experimentally evaluated with excellent agreement with numerical simulation. A focal volume (2.70 mm (axial)  ×  0.65 mm (transverse)  ×  0.35 mm (transverse)) defined by the  -6 dB focal intensity was obtained to address the dimensions needed for small animal therapy. An electronic beam steering range defined by the  -3 dB focal peak intensity (17 mm (axial)  ×  14 mm (transverse)  ×  12 mm (transverse)) and  -8 dB lateral grating lobes (24 mm (axial)  ×  18 mm (transverse)  ×  16 mm (transverse)) was achieved. The combined testing of imaging and therapeutic functions confirmed well-controlled local heating generation and imaging in a tissue mimicking phantom. This dual-array implementation offers a practical means to achieve hyperthermia and ablation in small animal models and can be incorporated within protocols for ultrasound-mediated drug delivery.

Development of a spherically focused phased array transducer for ultrasonic image-guided hyperthermia

Science.gov (United States)

Liu, Jingfei; Foiret, Josquin; Stephens, Douglas N.; Le Baron, Olivier; Ferrara, Katherine W.

2016-07-01

A 1.5 MHz prolate spheroidal therapeutic array with 128 circular elements was designed to accommodate standard imaging arrays for ultrasonic image-guided hyperthermia. The implementation of this dual-array system integrates real-time therapeutic and imaging functions with a single ultrasound system (Vantage 256, Verasonics). To facilitate applications involving small animal imaging and therapy the array was designed to have a beam depth of field smaller than 3.5 mm and to electronically steer over distances greater than 1 cm in both the axial and lateral directions. In order to achieve the required f number of 0.69, 1-3 piezocomposite modules were mated within the transducer housing. The performance of the prototype array was experimentally evaluated with excellent agreement with numerical simulation. A focal volume (2.70 mm (axial)  ×  0.65 mm (transverse)  ×  0.35 mm (transverse)) defined by the  -6 dB focal intensity was obtained to address the dimensions needed for small animal therapy. An electronic beam steering range defined by the  -3 dB focal peak intensity (17 mm (axial)  ×  14 mm (transverse)  ×  12 mm (transverse)) and  -8 dB lateral grating lobes (24 mm (axial)  ×  18 mm (transverse)  ×  16 mm (transverse)) was achieved. The combined testing of imaging and therapeutic functions confirmed well-controlled local heating generation and imaging in a tissue mimicking phantom. This dual-array implementation offers a practical means to achieve hyperthermia and ablation in small animal models and can be incorporated within protocols for ultrasound-mediated drug delivery.

Motorcycle detection and counting using stereo camera, IR camera, and microphone array

Science.gov (United States)

Ling, Bo; Gibson, David R. P.; Middleton, Dan

2013-03-01

Detection, classification, and characterization are the key to enhancing motorcycle safety, motorcycle operations and motorcycle travel estimation. Average motorcycle fatalities per Vehicle Mile Traveled (VMT) are currently estimated at 30 times those of auto fatalities. Although it has been an active research area for many years, motorcycle detection still remains a challenging task. Working with FHWA, we have developed a hybrid motorcycle detection and counting system using a suite of sensors including stereo camera, thermal IR camera and unidirectional microphone array. The IR thermal camera can capture the unique thermal signatures associated with the motorcycle's exhaust pipes that often show bright elongated blobs in IR images. The stereo camera in the system is used to detect the motorcyclist who can be easily windowed out in the stereo disparity map. If the motorcyclist is detected through his or her 3D body recognition, motorcycle is detected. Microphones are used to detect motorcycles that often produce low frequency acoustic signals. All three microphones in the microphone array are placed in strategic locations on the sensor platform to minimize the interferences of background noises from sources such as rain and wind. Field test results show that this hybrid motorcycle detection and counting system has an excellent performance.

Testing of ITER central solenoid coil insulation in an array

International Nuclear Information System (INIS)

Jayakumar, R.; Martovetsky, N.N.; Perfect, S.A.

1995-01-01

A glass-polyimide insulation system has been proposed by the US team for use in the Central Solenoid (CS) coil of the international Thermonuclear Experimental Reactor (ITER) machine and it is planned to use this system in the CS model coil inner module. The turn insulation will consist of 2 layers of combined prepreg and Kapton. Each layer is 50% overlapped with a butt wrap of prepreg and an overwrap of S glass. The coil layers will be separated by a glass-resin composite and impregnated in a VPI process. Small scale tests on the various components of the insulation are complete. It is planned to fabricate and test the insulation in a 4 x 4 insulated CS conductor array which will include the layer insulation and be vacuum impregnated. The conductor array will be subjected to 20 thermal cycles and 100000 mechanical load cycles in a Liquid Nitrogen environment. These loads are similar to those seen in the CS coil design. The insulation will be electrically tested at several stages during mechanical testing. This paper will describe the array configuration, fabrication: process, instrumentation, testing configuration, and supporting analyses used in selecting the array and test configurations

ArrayBridge: Interweaving declarative array processing with high-performance computing

Energy Technology Data Exchange (ETDEWEB)

Xing, Haoyuan [The Ohio State Univ., Columbus, OH (United States); Floratos, Sofoklis [The Ohio State Univ., Columbus, OH (United States); Blanas, Spyros [The Ohio State Univ., Columbus, OH (United States); Byna, Suren [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Prabhat, Prabhat [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Wu, Kesheng [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Brown, Paul [Paradigm4, Inc., Waltham, MA (United States)

2017-05-04

Scientists are increasingly turning to datacenter-scale computers to produce and analyze massive arrays. Despite decades of database research that extols the virtues of declarative query processing, scientists still write, debug and parallelize imperative HPC kernels even for the most mundane queries. This impedance mismatch has been partly attributed to the cumbersome data loading process; in response, the database community has proposed in situ mechanisms to access data in scientific file formats. Scientists, however, desire more than a passive access method that reads arrays from files. This paper describes ArrayBridge, a bi-directional array view mechanism for scientific file formats, that aims to make declarative array manipulations interoperable with imperative file-centric analyses. Our prototype implementation of ArrayBridge uses HDF5 as the underlying array storage library and seamlessly integrates into the SciDB open-source array database system. In addition to fast querying over external array objects, ArrayBridge produces arrays in the HDF5 file format just as easily as it can read from it. ArrayBridge also supports time travel queries from imperative kernels through the unmodified HDF5 API, and automatically deduplicates between array versions for space efficiency. Our extensive performance evaluation in NERSC, a large-scale scientific computing facility, shows that ArrayBridge exhibits statistically indistinguishable performance and I/O scalability to the native SciDB storage engine.

Interventional MRI of the breast: minimally invasive therapy

International Nuclear Information System (INIS)

Hall-Craggs, M.A.

2000-01-01

In recent years a variety of minimally invasive therapies have been applied to the treatment of breast lesions. These therapies include thermal treatments (interstitial laser coagulation, focused ultrasound, radiofrequency and cryotherapy), percutaneous excision, and interstitial radiotherapy. Magnetic resonance has been used in these treatments to visualize lesions before, during and after therapy and to guide interventions. ''Temperature-sensitive'' sequences have shown changes with thermal ablation which broadly correlate with areas of tumour necrosis. Consequently, MR has the potential to monitor treatment at the time of therapy. To date, experience in the treatment of breast cancer has been restricted to small studies. Large controlled studies are required to validate the efficacy and safety of these therapies in malignant disease. (orig.)

Fabrication of cell container arrays with overlaid surface topographies.

Science.gov (United States)

Truckenmüller, Roman; Giselbrecht, Stefan; Escalante-Marun, Maryana; Groenendijk, Max; Papenburg, Bernke; Rivron, Nicolas; Unadkat, Hemant; Saile, Volker; Subramaniam, Vinod; van den Berg, Albert; van Blitterswijk, Clemens; Wessling, Matthias; de Boer, Jan; Stamatialis, Dimitrios

2012-02-01

This paper presents cell culture substrates in the form of microcontainer arrays with overlaid surface topographies, and a technology for their fabrication. The new fabrication technology is based on microscale thermoforming of thin polymer films whose surfaces are topographically prepatterned on a micro- or nanoscale. For microthermoforming, we apply a new process on the basis of temporary back moulding of polymer films and use the novel concept of a perforated-sheet-like mould. Thermal micro- or nanoimprinting is applied for prepatterning. The novel cell container arrays are fabricated from polylactic acid (PLA) films. The thin-walled microcontainer structures have the shape of a spherical calotte merging into a hexagonal shape at their upper circumferential edges. In the arrays, the cell containers are arranged densely packed in honeycomb fashion. The inner surfaces of the highly curved container walls are provided with various topographical micro- and nanopatterns. For a first validation of the microcontainer arrays as in vitro cell culture substrates, C2C12 mouse premyoblasts are cultured in containers with microgrooved surfaces and shown to align along the grooves in the three-dimensional film substrates. In future stem-cell-biological and tissue engineering applications, microcontainers fabricated using the proposed technology may act as geometrically defined artificial microenvironments or niches.

Reduction of thermal conductivity in phononic nanomesh structures

KAUST Repository

Yu, Jen-Kan

2010-07-25

Controlling the thermal conductivity of a material independently of its electrical conductivity continues to be a goal for researchers working on thermoelectric materials for use in energy applications1,2 and in the cooling of integrated circuits3. In principle, the thermal conductivity κ and the electrical conductivity σ may be independently optimized in semiconducting nanostructures because different length scales are associated with phonons (which carry heat) and electric charges (which carry current). Phonons are scattered at surfaces and interfaces, so κ generally decreases as the surface-to-volume ratio increases. In contrast, σ is less sensitive to a decrease in nanostructure size, although at sufficiently small sizes it will degrade through the scattering of charge carriers at interfaces. Here, we demonstrate an approach to independently controlling κ based on altering the phonon band structure of a semiconductor thin film through the formation of a phononic nanomesh film. These films are patterned with periodic spacings that are comparable to, or shorter than, the phonon mean free path. The nanomesh structure exhibits a substantially lower thermal conductivity than an equivalently prepared array of silicon nanowires, even though this array has a significantly higher surface-to-volume ratio. Bulk-like electrical conductivity is preserved. We suggest that this development is a step towards a coherent mechanism for lowering thermal conductivity. © 2010 Macmillan Publishers Limited. All rights reserved.

Effects of fin pitch and array of the frost layer growth on extended surface of a heat exchanger

International Nuclear Information System (INIS)

Yang, Dong Keun; Lee, Kwan Soo

2003-01-01

This paper presents the effects of the fin array and pitch on the frost layer growth of a heat exchanger. The numerical results are compared with experimental data of a cold plate to validate the present model, and agree well with experimental data within a maximum error of 8%. The characteristics of the frost formation on staggered fin array are somewhat different from those of in-line array. For fin pitch below 10 mm, the frost layer growth of second fin in the staggered array is affected by that of first fin. The heat transfer of single fin deteriorate with decreasing fin pitch regardless of fin array, however, the thermal performance of a heat exchanger, considering increase of heat surface area, becomes better

Embedded Thermal Control for Spacecraft Subsystems Miniaturization

Science.gov (United States)

Didion, Jeffrey R.

2014-01-01

Optimization of spacecraft size, weight and power (SWaP) resources is an explicit technical priority at Goddard Space Flight Center. Embedded Thermal Control Subsystems are a promising technology with many cross cutting NSAA, DoD and commercial applications: 1.) CubeSatSmallSat spacecraft architecture, 2.) high performance computing, 3.) On-board spacecraft electronics, 4.) Power electronics and RF arrays. The Embedded Thermal Control Subsystem technology development efforts focus on component, board and enclosure level devices that will ultimately include intelligent capabilities. The presentation will discuss electric, capillary and hybrid based hardware research and development efforts at Goddard Space Flight Center. The Embedded Thermal Control Subsystem development program consists of interrelated sub-initiatives, e.g., chip component level thermal control devices, self-sensing thermal management, advanced manufactured structures. This presentation includes technical status and progress on each of these investigations. Future sub-initiatives, technical milestones and program goals will be presented.

Hyperspectral Longwave Infrared Focal Plane Array and Camera Based on Quantum Well Infrared Photodetectors, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — We propose to develop a hyperspectral focal plane array and camera imaging in a large number of sharp hyperspectral bands in the thermal infrared. The camera is...

Quantifying the Influence of Near-Surface Water-Energy Budgets on Soil Thermal Properties Using a Network of Coupled Meteorological and Vadose Zone Instrument Arrays in Indiana, USA

Science.gov (United States)

Naylor, S.; Gustin, A. R.; Ellett, K. M.

2012-12-01

Weather stations that collect reliable, sustained meteorological data sets are becoming more widely distributed because of advances in both instrumentation and data server technology. However, sites collecting soil moisture and soil temperature data remain sparse with even fewer locations where complete meteorological data are collected in conjunction with soil data. Thanks to the advent of sensors that collect continuous in-situ thermal properties data for soils, we have gone a step further and incorporated thermal properties measurements as part of hydrologic instrument arrays in central and northern Indiana. The coupled approach provides insights into the variability of soil thermal conductivity and diffusivity attributable to geologic and climatological controls for various hydrogeologic settings. These data are collected to facilitate the optimization of ground-source heat pumps (GSHPs) in the glaciated Midwest by establishing publicly available data that can be used to parameterize system design models. A network of six monitoring sites was developed in Indiana. Sensors that determine thermal conductivity and diffusivity using radial differential temperature measurements around a heating wire were installed at 1.2 meters below ground surface— a typical depth for horizontal GSHP systems. Each site also includes standard meteorological sensors for calculating reference evapotranspiration following the methods by the Food and Agriculture Organization (FAO) of the United Nations. Vadose zone instrumentation includes time domain reflectometry soil-moisture and temperature sensors installed at 0.3-meter depth intervals down to a 1.8-meter depth, in addition to matric potential sensors at 0.15, 0.3, 0.6, and 1.2 meters. Cores collected at 0.3-meter intervals were analyzed in a laboratory for grain size distribution, bulk density, thermal conductivity, and thermal diffusivity. Our work includes developing methods for calibrating thermal properties sensors based on

Advanced materials for thermal management of electronic packaging

CERN Document Server

Tong, Xingcun Colin

2011-01-01

The need for advanced thermal management materials in electronic packaging has been widely recognized as thermal challenges become barriers to the electronic industry's ability to provide continued improvements in device and system performance. With increased performance requirements for smaller, more capable, and more efficient electronic power devices, systems ranging from active electronically scanned radar arrays to web servers all require components that can dissipate heat efficiently. This requires that the materials have high capability of dissipating heat and maintaining compatibility

Remanence coercivity of dot arrays of hcp-CoPt perpendicular films

Energy Technology Data Exchange (ETDEWEB)

Mitsuzuka, K; Shimatsu, T; Aoi, H [Research Institute of Electrical Communication, Tohoku University, Sendai, 980-8577 (Japan); Kikuchi, N; Okamoto, S; Kitakami, O, E-mail: shimatsu@riec.tohoku.ac.j [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, 980-8577 (Japan)

2010-01-01

The remanence coercivity, H{sub r}, of hcp-CoPt dot arrays with various dot thicknesses, {delta}, (3 and 10 nm) and Pt content (20-30at%) were experimentally investigated as a function of the dot diameter, D(30-400 nm). All dot arrays showed a single domain state, even after removal of an applied field equal to H{sub r}. The angular dependence of H{sub r} for the dot arrays indicated coherent rotation of the magnetization during nucleation. H{sub r} increased as Ddecreased in all series of dot arrays with various {delta} and Pt content. Assuming that the nucleation field of a dot is determined by the switching field of a grain having the smallest switching field, we calculated the value of nucleation field H{sub n}{sup cal} taking account of the c-axis distribution and the distribution of the demagnetizing field in the dot. The values of H{sub r} obtained experimentally are in good agreement with those of H{sub n}{sup cal}, taking account of thermal agitation of magnetization. This result suggested that the reversal process of hcp-CoPt dot arrays starts from a nucleation at the center of the dot followed by a propagation process.

Low Frequency Phased Array Application for Crack Detection in Cast Austenitic Piping

International Nuclear Information System (INIS)

Anderson, Michael T.; Cumblidge, Stephen E.; Doctor, Steven R.

2006-01-01

As part of a multi-year program funded by the United States Nuclear Regulatory Commission (US NRC) to address nondestructive examination (NDE) reliability of inservice inspection (ISI) programs, studies conducted at the Pacific Northwest National Laboratory (PNNL) in Richland, Washington, have focused on assessing novel NDE approaches for the inspection of coarse-grained, cast stainless steel reactor components. The primary objective of this work is to provide information to the US NRC on the utility, effectiveness and reliability of ultrasonic testing (UT) as related to the ISI of primary piping components in US commercial nuclear power plants. This paper describes progress, recent developments and results from an assessment of a portion of the work relating to the ultrasonic low frequency phased array inspection technique. Westinghouse Owner's Group (WOG) cast stainless steel pipe segments with thermal and mechanical fatigue cracks, PNNL samples containing thermal fatigue cracks and several blank vintage specimens having very coarse grains that are representative of early centrifugally cast piping installed in PWRs, were used for assessing the inspection method. The phased array approach was implemented using an R/D Tech Tomoscan III system operating at 1.0 MHz and 500 kHz, providing composite volumetric images of the samples. Several dual, transmit-receive, custom designed low-frequency arrays were employed in laboratory trials. Results from laboratory studies for assessing detection, localization and length sizing effectiveness are discussed.

Thermal distribution in biological tissue at laser induced fluorescence and photodynamic therapy

Science.gov (United States)

Krasnikov, I. V.; Seteikin, A. Yu.; Drakaki, E.; Makropoulou, M.

2012-03-01

Laser induced fluorescence spectroscopy and photodynamic therapy (PDT) are techniques currently introduced in clinical applications for visualization and local destruction of malignant tumours as well as premalignant lesions. During the laser irradiation of tissues for the diagnostic and therapeutic purposes, the absorbed optical energy generates heat, although the power density of the treatment light for surface illumination is normally low enough not to cause any significantly increased tissue temperature. In this work we tried to evaluate the utility of Monte Carlo modeling for simulating the temperature fields and the dynamics of heat conduction into the skin tissue under several laser irradiation conditions with both a pulsed UV laser and a continuous wave visible laser beam. The analysis of the results showed that heat is not localized on the surface, but it is collected inside the tissue. By varying the boundary conditions on the surface and the type of the laser radiation (continuous or pulsed) we can reach higher than normal temperature inside the tissue without simultaneous formation of thermally damaged tissue (e.g. coagulation or necrosis zone).

Fabrication of non-hexagonal close packed colloidal array on a substrate by transfer

Science.gov (United States)

Banik, Meneka; Mukherjee, Rabibrata

Self-organized colloidal arrays find application in fabrication of solar cells with advanced light management strategies. We report a simple spincoating based approach for fabricating two dimensional colloidal crystals with hexagonal and non-hexagonal close packed assembly on flat and nanopatterned substrates. The non-HCP arrays were fabricated by spin coating the particles onto soft lithographically fabricated substrates. The substrate patterns impose directionality to the particles by confining them within the grooves. We have developed a technique by which the HCP and non-HCP arrays can be transferred to any surface. For this purpose the colloidal arrays were fabricated on a UV degradable PMMA layer, resulting in transfer of the particles on UV exposure. This allows the colloidal structures to be transported across substrates irrespective of their surface energy, wettability or morphology. Since the particles are transferred without exposing it to any kind of chemical or thermal environment, it can be utilized for placing particles on top of thin film solar cells for improving their absorption efficiency.

Performance of compact TES arrays with integrated high-fill-fraction X-ray absorbers

International Nuclear Information System (INIS)

Lindeman, Mark A.; Bandler, Simon; Brekosky, Regis P.; Chervenak, James A.; Figueroa-Feliciano, Enectali; Finkbeiner, Fred M.; Kelley, Richard L.; Saab, Tarek; Stahle, Caroline K.; Talley, D.J.

2004-01-01

We have recently produced and tested two-dimensional arrays of Mo/Au transition-edge-sensor (TES) calorimeters with Bi/Cu absorbers. The arrays represent a significant step towards meeting the specifications of NASA's Constellation-X mission. The calorimeters are compactly spaced within 5x5 arrays of 250 μm square pixels necessary for an angular resolution of 5 arcsec. Lithographically produced absorbers hang over the substrate and wiring between the TESs for high filling fraction and high quantum efficiency. We designed the calorimeters with heat capacities and thermal couplings such that X-rays produce pulses with fall times of approximately 300 μs to allow relatively high count rates with low dead time. We read out up to four of the pixels simultaneously. The arrays demonstrated very good energy resolution (5 eV at 1.5 keV and 7 eV at 6 keV) and little crosstalk between neighboring pixels

SiO{sub 2} nanodot arrays using functionalized block copolymer templates and selective silylation

Energy Technology Data Exchange (ETDEWEB)

Kim, Su Min; Ku, Se Jin; Kim, Jin-Baek, E-mail: kjb@kaist.ac.kr [Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), 373-1, Guseong-Dong, Yuseong-Gu, Daejeon, 305-701 (Korea, Republic of)

2010-06-11

Silicon oxide nanodot arrays were fabricated using functionalized block copolymer templates and selective silylation. A polystyrene-b-poly(acrylic acid/acrylic anhydride) (PS-b-PAA/AN) thin film containing spherical nanodomains was used as a template to build nanoscopic silica structures. A PS-b-PAA/AN thin film was prepared by acid-catalyzed thermal deprotection of polystyrene-b-poly(tert-butyl acrylate) on an SU-8 resist film containing a photoacid generator. This resulting film has excellent solvent and thermal resistance due to crosslinked anhydride linkages in carboxyl-functionalized PAA/AN block domains. Silicon was introduced by spin-spraying of hexamethyldisilazane (HMDS) over the entire surface of a self-assembled PS-b-PAA/AN thin film. HMDS was selectively reacted with carboxylic acid groups in spherical domains of a PAA/AN block. SiO{sub 2} nanodot arrays were generated by oxygen reactive ion etching.

Fabrication of carbon nanotube thermal interface material on aluminum alloy substrates with low pressure CVD

Energy Technology Data Exchange (ETDEWEB)

Gao, Z L; Zhang, K; Yuen, M M F, E-mail: megzl@ust.hk [Department of Mechanical Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong (Hong Kong)

2011-07-01

High quality vertically aligned carbon nanotube (VACNT) arrays have been synthesized on bulk Al alloy (Al6063) substrates with an electron-beam (E-beam) evaporated Fe catalyst using low pressure chemical vapor deposition (LPCVD). The pretreatment process of the catalyst was shown to play a critical role. This was studied comprehensively and optimized to repeatedly grow high quality VACNT arrays within a wide range of thicknesses of catalyst layer (2-11 nm) and acetylene (C{sub 2}H{sub 2}) flow rates (100-300 sccm). The thermal performance of the resulting VACNT arrays was evaluated. The minimum interfacial thermal resistance of the Si/VACNT/Al interfaces achieved so far is only 4 mm{sup 2} K W{sup -1}, and the average value is 14.6 mm{sup 2} K W{sup -1}.

Effect of spacers on the thermal performance of an annular multi-layer insulation

International Nuclear Information System (INIS)

Haim, Y.; Weiss, Y.; Letan, R.

2014-01-01

The current study presents a model and is experimentally conducted in a system of 40 stainless steel coaxial foils, of nitrogen gas, entrapped between the foils, and of spacers, which are zirconia, spherical, 50 μm in size particles, widely dispersed in the gaps between the foils. The model, experimentally verified, relates to radiation between the foils, unobstructed by particles, to conduction in the nitrogen gas, and to conduction across the particles. The study was, in particular, aimed to measure the effective thermal conductivity of the particles and to assess its effect upon the array. At vacuum of 0.092 Pa, the effective thermal conductivity of the particles was 2.13 × 10 −4  W/m K, while the effective thermal conductivity of the array was 4.74 × 10 −4  W/m K. Thus, the low contribution of the particles conduction at vacuum conditions improves the insulation. It reaches 45% of the heat transfer rate. At atmospheric pressure, the effective thermal conductivity of the array reaches 4.5 × 10 −2  W/m K. There, the spacers contribution is negligible. - Highlights: •The multi-layer insulation of cylinder consists of foils separated by particles. •The particles are widely spaced in gaps. •Particles heat transfer rate is almost half of the total in vacuum. •At higher pressures the particles contribution is negligible. •The predicted thermal performance agrees with experimental results

Infrared detectors and focal plane arrays II; Proceedings of the Meeting, Orlando, FL, Apr. 23, 24, 1992

Science.gov (United States)

Dereniak, Eustace L.; Sampson, Robert E.

The present conference discusses Schottky-barrier IR image sensors, SWIR and MWIR Schottky-barrier imagers, a 640 x 640 PtSi, models of nonlinearities in focal plane arrays, retinal function relative to IRT focal plane arrays, a solid-state pyroelectric imager, and electrolyte electroreflectance spectroscopies for the ion-implanted HgCdTe with thermal annealing. Also discussed are HgCdTe hybrid focal plane arrays for thermoelectrically cooled applications, a novel IR detector plasma-edge detector, and IR detector circuits using monolithic CMOS amps with InSb detectors. (No individual items are abstracted in this volume)

Use of thermal sieve to allow optical testing of cryogenic optical systems.

Science.gov (United States)

Kim, Dae Wook; Cai, Wenrui; Burge, James H

2012-05-21

Full aperture testing of large cryogenic optical systems has been impractical due to the difficulty of operating a large collimator at cryogenic temperatures. The Thermal Sieve solves this problem by acting as a thermal barrier between an ambient temperature collimator and the cryogenic system under test. The Thermal Sieve uses a set of thermally controlled baffles with array of holes that are lined up to pass the light from the collimator without degrading the wavefront, while attenuating the thermal background by nearly 4 orders of magnitude. This paper provides the theory behind the Thermal Sieve system, evaluates the optimization for its optical and thermal performance, and presents the design and analysis for a specific system.

Interventional MRI of the breast: minimally invasive therapy

Energy Technology Data Exchange (ETDEWEB)

Hall-Craggs, M.A. [MR Unit, Middlesex Hospital, London (United Kingdom)

2000-01-01

In recent years a variety of minimally invasive therapies have been applied to the treatment of breast lesions. These therapies include thermal treatments (interstitial laser coagulation, focused ultrasound, radiofrequency and cryotherapy), percutaneous excision, and interstitial radiotherapy. Magnetic resonance has been used in these treatments to visualize lesions before, during and after therapy and to guide interventions. ''Temperature-sensitive'' sequences have shown changes with thermal ablation which broadly correlate with areas of tumour necrosis. Consequently, MR has the potential to monitor treatment at the time of therapy. To date, experience in the treatment of breast cancer has been restricted to small studies. Large controlled studies are required to validate the efficacy and safety of these therapies in malignant disease. (orig.)

Passive Films for CubeSat Solar Array and Radiator Thermal Control

Data.gov (United States)

National Aeronautics and Space Administration — Trending towards reduced power and mass budget on satellites with a longer mission life, there is a need for a reliable thermal control system that is more efficient...

SU-E-T-111: Development of Proton Dosimetry System Using Fiber-Optic Cerenkov Radiation Sensor Array

Energy Technology Data Exchange (ETDEWEB)

Son, J [National Cancer Center, Ilsan, Gyeonggi-do, Korea University, Seoul (Korea, Republic of); Kim, M; Shin, D; Lim, Y; Lee, S; Kim, J; Kim, J [National Cancer Center, Goyangsi, Gyeonggi-do (Korea, Republic of); Hwang, U [National Medical Center in Korea, Seoul, Seoul (Korea, Republic of); Yoon, M [Korea University, Seoul (Korea, Republic of)

2014-06-01

Purpose: We had developed and evaluated a new dosimetric system for proton therapy using array of fiber-optic Cerenkov radiation sensor (FOCRS) which can measure a percent depth dose (PDD) instantly. In this study, the Bragg peaks and spread out Bragg peak (SOBP) of the proton beams measured by FOCRS array were compared with those measured by an ion chamber. Methods and Method: We fabricated an optical fiber array of FOCRS in a handmade phantom which is composed of poly-methyl methacrylate (PMMA). There are 75 holes of 1mm diameter inside the phantom which is designed to be exposed in direction of beam when it is emerged in water phantom. The proton beam irradiation was carried out using IBA cyclotron PROTEUS 235 at national cancer center in Korea and a commercial data acquisition system was used to digitize the analog signal. Results: The measured Bragg peak and SOBP for the proton ranges of 7∼ 20 cm were well matched with the result from ion chamber. The comparison results show that the depth of proton beam ranges and the width of SOBP measured by array of FOCRS are comparable with the measurement from multi-layer ion chamber (MLIC) although there are some uncertainty in the measurement of FOCRS array for some specific beam ranges. Conclusion: The newly developed FOCRS array based dosimetric system for proton therapy can efficiently reduce the time and effort needed for proton beam range measurement compared to the conventional method and has the potential to be used for the proton pencil beam application.

Hydrodynamics of single- and two-phase flow in inclined rod arrays

International Nuclear Information System (INIS)

Todreas, N.E.

1984-01-01

Required inputs for thermal-hydraulic codes are constitutive relations for fluid-solid flow resistance, in single-phase flow, and interfacial momentum exchange (relative phase motion), in two-phase flow. An inclined rod array air-water experiment was constructed to study the hydrodynamics of multidimensional porous medium flow in rod arrays. Velocities, pressures, bubble distributions, and void fractions were measured in inline and rotational square rod arrays of P/d = 1.5, at 0, 30, 45, and 90 degree inclinations to the vertical flow direction. Constitutive models for single-phase flow resistance are reviewed, new comprehensive models developed, and an assessment with previously published and new data made. The principle of superimposing one-dimensional correlations proves successful for turbulent single-phase inclined flow. For bubbly two-phase yawed flow through incline rod arrays a new flow separation phenomena was observed and modeled. Bubbles of diameters significantly smaller than the rod diameter travel along the rod axis, while larger diameter bubbles move through the rod array gaps. The outcome is a flow separation not predictable with current interfacial momentum exchange models. This phenomenon was not observed in rotated square rod arrays. Current interfacial momentum exchange models were confirmed for this rod arrangement. Models for the two phase flow resistance multiplier for cross flow were reviewed and compared with data from cross and yawed flow rod arrays. Both drag and lift components of the multiplier were well predicted by the homogenous model. Other models reviewed overpredicted the data by a factor of two

NovoTTF™-100A System (Tumor Treating Fields) transducer array layout planning for glioblastoma: a NovoTAL™ system user study.

Science.gov (United States)

Chaudhry, Aafia; Benson, Laura; Varshaver, Michael; Farber, Ori; Weinberg, Uri; Kirson, Eilon; Palti, Yoram

2015-11-11

Optune™, previously known as the NovoTTF-100A System™, generates Tumor Treating Fields (TTFields), an effective anti-mitotic therapy for glioblastoma. The system delivers intermediate frequency, alternating electric fields to the supratentorial brain. Patient therapy is personalized by configuring transducer array layout placement on the scalp to the tumor site using MRI measurements and the NovoTAL System. Transducer array layout mapping optimizes therapy by maximizing electric field intensity to the tumor site. This study evaluated physician performance in conducting transducer array layout mapping using the NovoTAL System compared with mapping performed by the Novocure in-house clinical team. Fourteen physicians (7 neuro-oncologists, 4 medical oncologists, and 3 neurosurgeons) evaluated five blinded cases of recurrent glioblastoma and performed head size and tumor location measurements using a standard Digital Imaging and Communications in Medicine reader. Concordance with Novocure measurement and intra- and inter-rater reliability were assessed using relevant correlation coefficients. The study criterion for success was a concordance correlation coefficient (CCC) >0.80. CCC for each physician versus Novocure on 20 MRI measurements was 0.96 (standard deviation, SD ± 0.03, range 0.90-1.00), indicating very high agreement between the two groups. Intra- and inter-rater reliability correlation coefficients were similarly high: 0.83 (SD ±0.15, range 0.54-1.00) and 0.80 (SD ±0.18, range 0.48-1.00), respectively. This user study demonstrated an excellent level of concordance between prescribing physicians and Novocure in-house clinical teams in performing transducer array layout planning. Intra-rater reliability was very high, indicating reproducible performance. Physicians prescribing TTFields, when trained on the NovoTAL System, can independently perform transducer array layout mapping required for the initiation and maintenance of patients on TTFields

Matrix-assisted energy conversion in nanostructured piezoelectric arrays

Science.gov (United States)

Sirbuly, Donald J.; Wang, Xianying; Wang, Yinmin

2013-01-01

A nanoconverter is capable of directly generating electricity through a nanostructure embedded in a polymer layer experiencing differential thermal expansion in a stress transfer zone. High surface-to-volume ratio semiconductor nanowires or nanotubes (such as ZnO, silicon, carbon, etc.) are grown either aligned or substantially vertically aligned on a substrate. The resulting nanoforest is then embedded with the polymer layer, which transfers stress to the nanostructures in the stress transfer zone, thereby creating a nanostructure voltage output due to the piezoelectric effect acting on the nanostructure. Electrodes attached at both ends of the nanostructures generate output power at densities of .about.20 nW/cm.sup.2 with heating temperatures of .about.65.degree. C. Nanoconverters arrayed in a series parallel arrangement may be constructed in planar, stacked, or rolled arrays to supply power to nano- and micro-devices without use of external batteries.

Poster - Thurs Eve-09: Evaluation of a commercial 2D ion-chamber array for intensity modulated radiation therapy dose measurements.

Science.gov (United States)

Mei, X; Bracken, G; Kerr, A

2008-07-01

Experimental verification of calculated dose from a treatment planning system is often essential for quality assurance (QA) of intensity modulated radiation therapy (IMRT). Film dosimetry and single ion chamber measurements are commonly used for IMRT QA. Film dosimetry has very good spatial resolution, but is labor intensive and absolute dose is not reliable. Ion chamber measurements are still required for absolute dose after measurements using films. Dosimeters based on 2D detector arrays that can measure 2D dose in real-time are gaining wider use. These devices provide a much easier and reliable tool for IMRT QA. We report the evaluation of a commercial 2D ion chamber array, including its basic performance characteristics, such as linearity, reproducibility and uniformity of relative ion chamber sensitivities, and comparisons between measured 2D dose and calculated dose with a commercial treatment planning system. Our analysis shows this matrix has excellent linearity and reproducibility, but relative sensitivities are tilted such that the +Y region is over sensitive, while the -Y region is under sensitive. Despite this behavior, our results show good agreement between measured 2D dose profiles and Eclipse planned data for IMRT test plans and a few verification plans for clinical breast field-in-field plans. The gamma values (3% or 3 mm distance-to-agreement) are all less than 1 except for one or two pixels at the field edge This device provides a fast and reliable stand-alone dosimeter for IMRT QA. © 2008 American Association of Physicists in Medicine.

Therapy: a new nonsurgical therapy option for benign thyroid nodules?

DEFF Research Database (Denmark)

Hegedüs, Laszlo

2009-01-01

Despite the increasing implementation of iodization programs, benign nodular thyroid disease will remain a prevalent therapeutic concern for decades. recent research suggests that nonsurgical therapy, including radioactive iodine, radiofrequency thermal ablation and percutaneous laser ablation, m...

DWDM laser arrays fabricated using thermal nanoimprint lithography on Indium Phosphide substrates

DEFF Research Database (Denmark)

Smistrup, K.; Nørregaard, J.; Mironov, A.

2013-01-01

by including a lambda quarter shift at the center of the grating. The need for phase shifts and multiple wavelengths eliminates some lithography methods such as holography. Typically, these lasers are produced by e-beam lithography (EBL). We present a production method based on thermal nanoimprint lithography...... during the imprint process and the narrow temperature window for imprint and separation (80°C and 55°C) ensures minimal issues with thermal mismatch between the InP substrate and the Si stamp. The imprinted InP wafers were processed in NeoPhotonics standard process line to create working lasers...

Thermally modulated biomolecule transport through nanoconfined channels.

Science.gov (United States)

Liu, Lei; Zhu, Lizhong

2015-01-01

In this work, a nanofluidic device containing both a feed cell and a permeation cell linked by nanopore arrays has been fabricated, which is employed to investigate thermally controlled biomolecular transporting properties through confined nanochannels. The ionic currents modulated by the translocations of goat antibody to human immunoglobulin G (IgG) or bovine serum albumin (BSA) are recorded and analyzed. The results suggest that the modulation effect decreases with the electrolyte concentration increasing, while the effects generated by IgG translocation are more significant than that generated by BSA translocation. More importantly, there is a maximum decreasing value in each modulated current curve with biomolecule concentration increasing for thermally induced intermolecular collision. Furthermore, the turning point for the maximum shifts to lower biomolecule concentrations with the system temperature rising (from 4°C to 45°C), and it is mainly determined by the temperature in the feed cell if the temperature difference exists in the two separated cells. These findings are expected to be valuable for the future design of novel sensing device based on nanopore and/or nanopore arrays.

OPTIONS FOR USE OF APPROPRIATE ANTICOAGULANT THERAPY IN PATIENTS WITH THERMAL INJURY WITH A HIGH RISK OF THROMBOEMBOLIC COMPLICATIONS DEVELOPMENT ASSOCIATED WITH RECURRENT INTESTINAL BLEEDING

Directory of Open Access Journals (Sweden)

V. S. Borisov

2015-01-01

Full Text Available ABSTRACT. Patients with major thermal injury require anticoagulant therapy during almost the whole period of the burn disease, forcing the physician to balance constantly between the risk of possible bleeding associated with surgical treatment and the risk of thrombosis development in patients demonstrating a number of factors predisposing to the development of VTС. We report a clinical case of appropriate anticoagulant therapy using the new oral anticoagulants in a patient with a high risk of VTС development and recurrent bleeding from the tumor of the ascending colon. 

Thermal architecture of the SPICA/SAFARI instrument

Science.gov (United States)

Charles, Ivan; Duband, Lionel; Duval, Jean-Marc; Jackson, Brian; Jellema, Willem; Kooijman, Peter Paul; Luchier, Nicolas; Tirolien, Thierry; van Weers, Henk

2012-09-01

The SAFARI instrument is a far infrared imaging spectrometer that is a core instrument of the SPICA mission. Thanks to the large (3 meter) SPICA cold telescope, the ultra sensitive detectors and a powerful Fourier Transform Spectrometer, this instrument will give access to the faintest light never observed in the 34 μm - 210 μm bandwidth with a high spectral resolution. To achieve this goal, TES detectors, that need to be cooled at a temperature as low as 50 mK, have been chosen. The thermal architecture of the SAFARI focal plane unit (FPU) which fulfils the TES detector thermal requirements is presented. In particular, an original 50 mK cooler concept based on a sorption cooler in series with an adiabatic demagnetization refrigerator will be used. The thermal design of the detector focal plane array (FPA) that uses three temperature stages to limit the loads on the lowest temperature stage, will be also described. The current SAFARI thermal budget estimations are presented and discussed regarding the limited SPICA allocations. Finally, preliminary thermal sensitivity analysis dealing with thermal stability requirements is presented.

A dual-mode hemispherical sparse array for 3D passive acoustic mapping and skull localization within a clinical MRI guided focused ultrasound device

Science.gov (United States)

Crake, Calum; Brinker, Spencer T.; Coviello, Christian M.; Livingstone, Margaret S.; McDannold, Nathan J.

2018-03-01

Previous work has demonstrated that passive acoustic imaging may be used alongside MRI for monitoring of focused ultrasound therapy. However, past implementations have generally made use of either linear arrays originally designed for diagnostic imaging or custom narrowband arrays specific to in-house therapeutic transducer designs, neither of which is fully compatible with clinical MR-guided focused ultrasound (MRgFUS) devices. Here we have designed an array which is suitable for use within an FDA-approved MR-guided transcranial focused ultrasound device, within the bore of a 3 Tesla clinical MRI scanner. The array is constructed from 5  ×  0.4 mm piezoceramic disc elements arranged in pseudorandom fashion on a low-profile laser-cut acrylic frame designed to fit between the therapeutic elements of a 230 kHz InSightec ExAblate 4000 transducer. By exploiting thickness and radial resonance modes of the piezo discs the array is capable of both B-mode imaging at 5 MHz for skull localization, as well as passive reception at the second harmonic of the therapy array for detection of cavitation and 3D passive acoustic imaging. In active mode, the array was able to perform B-mode imaging of a human skull, showing the outer skull surface with good qualitative agreement with MR imaging. Extension to 3D showed the array was able to locate the skull within  ±2 mm/2° of reference points derived from MRI, which could potentially allow registration of a patient to the therapy system without the expense of real-time MRI. In passive mode, the array was able to resolve a point source in 3D within a  ±10 mm region about each axis from the focus, detect cavitation (SNR ~ 12 dB) at burst lengths from 10 cycles to continuous wave, and produce 3D acoustic maps in a flow phantom. Finally, the array was used to detect and map cavitation associated with microbubble activity in the brain in nonhuman primates.

ALMA Thermal Observations of a Proposed Plume Source Region on Europa

Energy Technology Data Exchange (ETDEWEB)

Trumbo, Samantha K.; Brown, Michael E. [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Butler, Bryan J. [National Radio Astronomy Observatory, Socorro, NM 87801 (United States)

2017-10-01

We present a daytime thermal image of Europa taken with the Atacama Large Millimeter Array. The imaged region includes the area northwest of Pwyll Crater, which is associated with a nighttime thermal excess seen by the Galileo Photopolarimeter Radiometer and with two potential plume detections. We develop a global thermal model of Europa and simulate both the daytime and nighttime thermal emission to determine if the nighttime thermal anomaly is caused by excess endogenic heat flow, as might be expected from a plume source region. We find that the nighttime and daytime brightness temperatures near Pwyll Crater cannot be matched by including excess heat flow at that location. Rather, we can successfully model both measurements by increasing the local thermal inertia of the surface.

Thermal Performance and Reliability Characterization of Bonded Interface Materials (BIMs): Preprint

Energy Technology Data Exchange (ETDEWEB)

DeVoto, D.; Paret, P.; Mihalic, M.; Narumanchi, S.; Bar-Cohen, A.; Matin, K.

2014-08-01

Thermal interface materials are an important enabler for low thermal resistance and reliable electronics packaging for a wide array of applications. There is a trend towards bonded interface materials (BIMs) because of their potential for low thermal resistivity (< 1 mm2K/W). However, BIMs induce thermomechanical stresses in the package and can be prone to failures and integrity risks. Deteriorated interfaces can result in high thermal resistance in the package and degradation and/or failure of the electronics. DARPA's Thermal Management Technologies program has addressed this challenge, supporting the development of mechanically-compliant, low resistivity nano-thermal interface (NTI) materials. In this work, we describe the testing procedure and report the results of NREL's thermal performance and reliability characterization of an initial sample of four different NTI-BIMs.

Template-based preparation of free-standing semiconducting polymeric nanorod arrays on conductive substrates.

Science.gov (United States)

Haberkorn, Niko; Weber, Stefan A L; Berger, Rüdiger; Theato, Patrick

2010-06-01

We describe the synthesis and characterization of a cross-linkable siloxane-derivatized tetraphenylbenzidine (DTMS-TPD), which was used for the fabrication of semiconducting highly ordered nanorod arrays on conductive indium tin oxide or Pt-coated substrates. The stepwise process allow fabricating of macroscopic areas of well-ordered free-standing nanorod arrays, which feature a high resistance against organic solvents, semiconducting properties and a good adhesion to the substrate. Thin films of the TPD derivate with good hole-conducting properties could be prepared by cross-linking and covalently attaching to hydroxylated substrates utilizing an initiator-free thermal curing at 160 degrees C. The nanorod arrays composed of cross-linked DTMS-TPD were fabricated by an anodic aluminum oxide (AAO) template approach. Furthermore, the nanorod arrays were investigated by a recently introduced method allowing to probe local conductivity on fragile structures. It revealed that more than 98% of the nanorods exhibit electrical conductance and consequently feature a good electrical contact to the substrate. The prepared nanorod arrays have the potential to find application in the fabrication of multilayered device architectures for building well-ordered bulk-heterojunction solar cells.

Progress on conformal microwave array applicators for heating chestwall disease

Science.gov (United States)

Stauffer, P. R.; Maccarini, P. F.; Juang, T.; Jacobsen, S. K.; Gaeta, C. J.; Schlorff, J. L.; Milligan, A. J.

2007-02-01

Previous studies have reported the computer modeling, CAD design, and theoretical performance of single and multiple antenna arrays of Dual Concentric Conductor (DCC) square slot radiators driven at 915 and 433 MHz. Subsequently, practical CAD designs of microstrip antenna arrays constructed on thin and flexible printed circuit board (PCB) material were reported which evolved into large Conformal Microwave Array (CMA) sheets that could wrap around the surface of the human torso for delivering microwave energy to large areas of superficial tissue. Although uniform and adjustable radiation patterns have been demonstrated from multiple element applicators radiating into simple homogeneous phantom loads, the contoured and heterogeneous tissue loads typical of chestwall recurrent breast cancer have required additional design efforts to achieve good coupling and efficient heating from the increasingly larger conformal array applicators used to treat large area contoured patient anatomy. Thus recent work has extended the theoretical optimization of DCC antennas to improve radiation efficiency of each individual aperture and reduce mismatch reflections, radiation losses, noise, and cross coupling of the feedline distribution network of large array configurations. Design improvements have also been incorporated into the supporting bolus structure to maintain effective coupling of DCC antennas into contoured anatomy and to monitor and control surface temperatures under the entire array. New approaches for non-invasive monitoring of surface and sub-surface tissue temperatures under each independent heat source are described that make use of microwave radiometry and flexible sheet grid arrays of thermal sensors. Efforts to optimize the clinical patient interface and move from planar rectangular shapes to contoured vest applicators that accommodate entire disease in a larger number of patients are summarized. By applying heat more uniformly to large areas of contoured anatomy

Experimental investigations of an endoluminal ultrasound applicator for MR-guided thermal therapy of pancreatic cancer

Science.gov (United States)

Adams, Matthew; Salgaonkar, Vasant; Jones, Peter; Plata, Juan; Chen, Henry; Pauly, Kim Butts; Sommer, Graham; Diederich, Chris

2017-03-01

An MR-guided endoluminal ultrasound applicator has been proposed for palliative and potential curative thermal therapy of pancreatic tumors. Minimally invasive ablation or hyperthermia treatment of pancreatic tumor tissue would be performed with the applicator positioned in the gastrointestinal (GI) lumen, and sparing of the luminal tissue would be achieved with a water-cooled balloon surrounding the ultrasound transducers. This approach offers the capability of conformal volumetric therapy for fast treatment times, with control over the 3D spatial deposition of energy. Prototype endoluminal ultrasound applicators have been fabricated using 3D printed fixtures that seat two 3.2 or 5.6 MHz planar or curvilinear transducers and contain channels for wiring and water flow. Spiral surface coils have been integrated onto the applicator body to allow for device localization and tracking for therapies performed under MR guidance. Heating experiments with a tissue-mimicking phantom in a 3T MR scanner were performed and demonstrated capability of the prototype to perform volumetric heating through duodenal luminal tissue under real-time PRF-based MR temperature imaging (MRTI). Additional experiments were performed in ex vivo pig carcasses with the applicator inserted into the esophagus and aimed towards liver or soft tissue surrounding the spine under MR guidance. These experiments verified the capacity of heating targets up to 20-25 mm from the GI tract. Active device tracking and automated prescription of imaging and temperature monitoring planes through the applicator were made possible by using Hadamard encoded tracking sequences to obtain the coordinates of the applicator tracking coils. The prototype applicators have been integrated with an MR software suite that performs real-time device tracking and temperature monitoring.

A Facile Method for Loading CeO2 Nanoparticles on Anodic TiO2 Nanotube Arrays.

Science.gov (United States)

Liao, Yulong; Yuan, Botao; Zhang, Dainan; Wang, Xiaoyi; Li, Yuanxun; Wen, Qiye; Zhang, Huaiwu; Zhong, Zhiyong

2018-04-03

In this paper, a facile method was proposed to load CeO 2 nanoparticles (NPs) on anodic TiO 2 nanotube (NT) arrays, which leads to a formation of CeO 2 /TiO 2 heterojunctions. Highly ordered anatase phase TiO 2 NT arrays were fabricated by using anodic oxidation method, then these individual TiO 2 NTs were used as tiny "nano-containers" to load a small amount of Ce(NO 3 ) 3 solutions. The loaded anodic TiO 2 NTs were baked and heated to a high temperature of 450 °C, under which the Ce(NO 3 ) 3 would be thermally decomposed inside those nano-containers. After the thermal decomposition of Ce(NO 3 ) 3 , cubic crystal CeO 2 NPs were obtained and successfully loaded into the anodic TiO 2 NT arrays. The prepared CeO 2 /TiO 2 heterojunction structures were characterized by a variety of analytical technologies, including XRD, SEM, and Raman spectra. This study provides a facile approach to prepare CeO 2 /TiO 2 films, which could be very useful for environmental and energy-related areas.

Natural convection heat transfer for a staggered array of heated, horizontal cylinders within a rectangular enclosure

Energy Technology Data Exchange (ETDEWEB)

Triplett, C.E.

1996-12-01

This thesis presents the results of an experimental investigation of natural convection heat transfer in a staggered array of heated cylinders, oriented horizontally within a rectangular enclosure. The main purpose of this research was to extend the knowledge of heat transfer within enclosed bundles of spent nuclear fuel rods sealed within a shipping or storage container. This research extends Canaan`s investigation of an aligned array of heated cylinders that thermally simulated a boiling water reactor (BWR) spent fuel assembly sealed within a shipping or storage cask. The results are presented in terms of piecewise Nusselt-Rayleigh number correlations of the form Nu = C(Ra){sup n}, where C and n are constants. Correlations are presented both for individual rods within the array and for the array as a whole. The correlations are based only on the convective component of the heat transfer. The radiative component was calculated with a finite-element code that used measured surface temperatures, rod array geometry, and measured surface emissivities as inputs. The correlation results are compared to Canaan`s aligned array results and to other studies of natural convection in horizontal tube arrays.

Natural convection heat transfer for a staggered array of heated, horizontal cylinders within a rectangular enclosure

International Nuclear Information System (INIS)

Triplett, C.E.

1996-12-01

This thesis presents the results of an experimental investigation of natural convection heat transfer in a staggered array of heated cylinders, oriented horizontally within a rectangular enclosure. The main purpose of this research was to extend the knowledge of heat transfer within enclosed bundles of spent nuclear fuel rods sealed within a shipping or storage container. This research extends Canaan's investigation of an aligned array of heated cylinders that thermally simulated a boiling water reactor (BWR) spent fuel assembly sealed within a shipping or storage cask. The results are presented in terms of piecewise Nusselt-Rayleigh number correlations of the form Nu = C(Ra) n , where C and n are constants. Correlations are presented both for individual rods within the array and for the array as a whole. The correlations are based only on the convective component of the heat transfer. The radiative component was calculated with a finite-element code that used measured surface temperatures, rod array geometry, and measured surface emissivities as inputs. The correlation results are compared to Canaan's aligned array results and to other studies of natural convection in horizontal tube arrays

Boron neutron capture therapy (BNCT). Recent aspect, a change from thermal neutron to epithermal neutron beam and a new protocol

International Nuclear Information System (INIS)

Nakagawa, Yoshinobu

1999-01-01

Since 1968, One-hundred seventy three patients with glioblastoma (n=81), anaplastic astrocytoma (n=44), low grade astrocytoma (n=16) or other types of tumor (n=32) were treated by boron-neutron capture therapy (BNCT) using a combination of thermal neutron and BSH in 5 reactors (HTR n=13, JRR-3 n=1, MuITR n=98, KUR n=28, JRR-2 n=33). Out of 101 patients with glioma treated by BNCT under the recent protocol, 33 (10 glioblastoma, 14 anaplastic astrocytoma, 9 low grade astrocytoma) patients lived or have lived longer than 3 years. Nine of these 33 lived or have lived longer than 10 years. According to the retrospective analysis, the important factors related to the clinical results were tumor dose radiation dose and maximum radiation dose in thermal brain cortex. The result was not satisfied as it was expected. Then, we decided to introduce mixed beams which contain thermal neutron and epithermal neutron beams. KUR was reconstructed in 1996 and developed to be available to use mixed beams. Following the shutdown of the JRR-2, JRR-4 was renewed for medical use in 1998. Both reactors have capacity to yield thermal neutron beam, epithermal neutron beam and mixed beams. The development of the neutron source lead us to make a new protocol. (author)

Innovative Solar Tracking Concept by Rotating Prism Array

Directory of Open Access Journals (Sweden)

Héctor García

2014-01-01

Full Text Available Solar energy has become one of the most promising renewable energies and is the most widely used nowadays. In order to achieve an optimum performance, both photovoltaic and solar thermal applications are required to track the position of the sun throughout the day and year in the most effective way possible to avoid a high negative impact on the system efficiency. The present paper attempts to describe a novel semipassive solar tracking concentrator (SPSTC in which, in order to track the sun, two independent arrays of polymethyl methacrylate (PMMA prisms are implemented to refract sunlight by rotating said prisms, thus being able to redirect solar radiation as desired. The first set is responsible for eliminating one of the directional components of the solar radiation; the task is achieved by rotating the prisms within the array at a specific angle. The second set deals with another of the sunlight’s directional components, transforming its direction into a completely perpendicular pattern to the array. Having downward vertical radiation makes it possible to implement a stationary Fresnel lens to concentrate the solar radiation for any application desired. The system is designed and validated using simulation software to prove the feasibility of the concept.

[Play therapy--psychotherapy with play as the medium: II. New developments].

Science.gov (United States)

von Gontard, Alexander; Lehmkuhl, Gerd

2003-02-01

A wide array of new forms and combinations of play therapy have been developed. The aim of the second part of this paper is to present an overview of these newer approaches, including: focussed therapies for specific disorders; behavioural approaches like the Cognitive-Behavioral Play Therapy and the Parent-Child Interaction Therapy; various combinations with family therapy; and therapies especially for preschool children like Filial Therapy, Developmental Play Therapy and Thera-play. Following a phase of experiments and combinations, the empirical evaluation of many play-therapy forms is needed. Especially questions of the differential indication of specific play-therapies and their effectiveness in the therapeutical practice need to be studied.

Improving Reliability of High Power Quasi-CW Laser Diode Arrays Operating in Long Pulse Mode

Science.gov (United States)

Amzajerdian, Farzin; Meadows, Byron L.; Barnes, Bruce W.; Lockard, George E.; Singh, Upendra N.; Kavaya, Michael J.; Baker, Nathaniel R.

2006-01-01

Operating high power laser diode arrays in long pulse regime of about 1 msec, which is required for pumping 2-micron thulium and holmium-based lasers, greatly limits their useful lifetime. This paper describes performance of laser diode arrays operating in long pulse mode and presents experimental data of the active region temperature and pulse-to-pulse thermal cycling that are the primary cause of their premature failure and rapid degradation. This paper will then offer a viable approach for determining the optimum design and operational parameters leading to the maximum attainable lifetime.

Improving Lifetime of Quasi-CW Laser Diode Arrays for Pumping 2-Micron Solid State Lasers

Science.gov (United States)

Amzajerdian, Farzin; Meadows, Byron L.; Baker, Nathaniel R.; Barnes, Bruce W.; Singh, Upendra N.; Kavaya, Michael J.

2007-01-01

Operating high power laser diode arrays in long pulse regime of about 1 msec, which is required for pumping 2-micron thulium and holmium-based lasers, greatly limits their useful lifetime. This paper describes performance of laser diode arrays operating in long pulse mode and presents experimental data on the active region temperature and pulse-to-pulse thermal cycling that are the primary cause of their premature failure and rapid degradation. This paper will then offer a viable approach for determining the optimum design and operational parameters leading to the maximum attainable lifetime.

A novel method for the fabrication of a high-density carbon nanotube microelectrode array

Directory of Open Access Journals (Sweden)

Adam Khalifa

2015-09-01

Full Text Available We present a novel method for fabricating a high-density carbon nanotube microelectrode array (MEA chip. Vertically aligned carbon nanotubes (VACNTs were synthesized by microwave plasma-enhanced chemical vapor deposition and thermal chemical vapor deposition. The device was characterized using electrochemical experiments such as cyclic voltammetry, impedance spectroscopy and potential transient measurements. Through-silicon vias (TSVs were fabricated and partially filled with polycrystalline silicon to allow electrical connection from the high-density electrodes to a stimulator microchip. In response to the demand for higher resolution implants, we have developed a unique process to obtain a high-density electrode array by making the microelectrodes smaller in size and designing new ways of routing the electrodes to current sources. Keywords: Microelectrode array, Neural implant, Carbon nanotubes, Through-silicon via interconnects, Microfabrication

SNP Arrays

Directory of Open Access Journals (Sweden)

Jari Louhelainen

2016-10-01

Full Text Available The papers published in this Special Issue “SNP arrays” (Single Nucleotide Polymorphism Arrays focus on several perspectives associated with arrays of this type. The range of papers vary from a case report to reviews, thereby targeting wider audiences working in this field. The research focus of SNP arrays is often human cancers but this Issue expands that focus to include areas such as rare conditions, animal breeding and bioinformatics tools. Given the limited scope, the spectrum of papers is nothing short of remarkable and even from a technical point of view these papers will contribute to the field at a general level. Three of the papers published in this Special Issue focus on the use of various SNP array approaches in the analysis of three different cancer types. Two of the papers concentrate on two very different rare conditions, applying the SNP arrays slightly differently. Finally, two other papers evaluate the use of the SNP arrays in the context of genetic analysis of livestock. The findings reported in these papers help to close gaps in the current literature and also to give guidelines for future applications of SNP arrays.

A novel method to design sparse linear arrays for ultrasonic phased array.

Science.gov (United States)

Yang, Ping; Chen, Bin; Shi, Ke-Ren

2006-12-22

In ultrasonic phased array testing, a sparse array can increase the resolution by enlarging the aperture without adding system complexity. Designing a sparse array involves choosing the best or a better configuration from a large number of candidate arrays. We firstly designed sparse arrays by using a genetic algorithm, but found that the arrays have poor performance and poor consistency. So, a method based on the Minimum Redundancy Linear Array was then adopted. Some elements are determined by the minimum-redundancy array firstly in order to ensure spatial resolution and then a genetic algorithm is used to optimize the remaining elements. Sparse arrays designed by this method have much better performance and consistency compared to the arrays designed only by a genetic algorithm. Both simulation and experiment confirm the effectiveness.

Tumour Debulking for Esophageal Cancer - Thermal Modalities

Directory of Open Access Journals (Sweden)

David Fleischer

1992-01-01

Full Text Available Esophageal cancer usually is discovered at a late stage and curative therapy seldom is possible. The prognosis is poor and most therapy is palliative. Endoscopic therapy commonly is employed; two common treatments involve thermal modalities. The Nd:YAG laser has been employed for 10 years and is effective in relieving obstruction in approximately 90% of cases. Re-ohstruction usually occurs in two to three months and repeat treatment may be necessary. Limitations to laser use include the fact that equipment is expensive and there are technical restrictions. An alternative thermal modality is the bipolar coagulation tumour probe which employs bipolar electrocoagulation. It is less expensive and, if the tumour is circumferential, tends to be easier to use. (It should not be used if the cancer is noncircumferential. The advantages and limitations of each modality are addressed.

Simulation of surface cracks measurement in first walls by laser spot array thermography

Energy Technology Data Exchange (ETDEWEB)

Pei, Cuixiang; Qiu, Jinxin; Liu, Haocheng; Chen, Zhenmao, E-mail: chenzm@mail.xjtu.edu.cn

2016-11-01

The inspection of surface cracks in first walls (FW) is very important to ensure the safe operation of the fusion reactors. In this paper, a new laser excited thermography technique with using laser spot array source is proposed for the surface cracks imaging and evaluation in the FW with an intuitive and non-contact measurement method. Instead of imaging a crack by scanning a single laser spot and superimposing the local discontinuity images with the present laser excited thermography methods, it can inspect a relatively large area at one measurement. It does not only simplify the measurement system and data processing procedure, but also provide a faster measurement for FW. In order to investigate the feasibility of this method, a numerical code based on finite element method (FEM) is developed to simulate the heat flow and the effect of the crack geometry on the thermal wave fields. An imaging method based on the gradient of the thermal images is proposed for crack measurement with the laser spot array thermography method.

A test-type hyper-thermal neutron generator for neutron capture therapy - estimation of neutron energy spectrum by simulation calculations and TOF experiments

International Nuclear Information System (INIS)

Sakurai, Yoshinori; Kobayashi, Tooru; Kobayashi, Katsuhei

1999-01-01

In order to clarify the irradiation characteristics of hyper-thermal neutrons and the feasibility of a hyper-thermal neutron irradiation field for neutron capture therapy, a 'test-type' hyper-thermal neutron generator was designed and made. Graphite of 6 cm thickness and 21 cm diameter was selected as the high temperature scatterer. The scatterer is heated up to 1200 deg. C maximum using molybdenum heaters. The radiation heat is shielded by reflectors of molybdenum and stainless steel. The temperature is measured using three R-type thermo-couples and controlled by a program controller. The total thickness of the generator is designed to be as thin as possible, 20 cm in maximum, in the standing point of the neutron beam intensity. The thermal stability, controllability and safety of the generator at high temperature employment were confirmed by the heating tests. As one of the experiments for the characteristics estimation, the neutron energy spectrum dependent on the scatterer temperature was measured by the TOF (time of flight) method using the LINAC neutron generator. The estimations by simulation calculations were also performed. From the experiment and calculation results, it was confirmed that the neutron temperature shifted higher as the scatterer temperature was higher. The prospect of the feasibility of the 'hyper-thermal neutron irradiation field for NCT' was opened from the estimation results of the generator characteristics by the simulation calculations and experiments

Thermal Mud Molecular Overview

Directory of Open Access Journals (Sweden)

Ersin Odabasi

2014-06-01

Full Text Available Thermal mud (peloids, which are frequently used for thermal therapy purposes consist of organic and inorganic (minerals compounds in general. Organic structure is formed after a variety of chemical processes occurring in decades and comprise of a very complex structure. Stagnant water environment, herbal diversity, microorganism multiplicity and time are crucial players to form the structure. Data regarding description of organic compounds are very limited. Nowadays, it was clearly understood that a variety of compounds those are neglected in daily practice are found in thermal mud after GC-MS and similar methods are being frequently used. Those compounds which are biologically active are humic compounds, carboxylic acids, terpenoids, steroids and fatty acids. By comprising the thermal mud, these different compound groups which are related to divers areas from cosmetology to inflammation, make the thermal mud very meaningful in the treatment of human disease. In this review, it was tried to put forward the effects of several molecule groups those consisting of the thermal mud structure. [TAF Prev Med Bull 2014; 13(3.000: 257-264

High accuracy thermal conductivity measurement of aqueous cryoprotective agents and semi-rigid biological tissues using a microfabricated thermal sensor

Science.gov (United States)

Liang, Xin M.; Sekar, Praveen K.; Zhao, Gang; Zhou, Xiaoming; Shu, Zhiquan; Huang, Zhongping; Ding, Weiping; Zhang, Qingchuan; Gao, Dayong

2015-01-01

An improved thermal-needle approach for accurate and fast measurement of thermal conductivity of aqueous and soft biomaterials was developed using microfabricated thermal conductivity sensors. This microscopic measuring device was comprehensively characterized at temperatures from 0 °C to 40 °C. Despite the previous belief, system calibration constant was observed to be highly temperature-dependent. Dynamic thermal conductivity response during cooling (40 °C to –40 °C) was observed using the miniaturized single tip sensor for various concentrations of CPAs, i.e., glycerol, ethylene glycol and dimethyl sulfoxide. Chicken breast, chicken skin, porcine limb, and bovine liver were assayed to investigate the effect of anatomical heterogeneity on thermal conductivity using the arrayed multi-tip sensor at 20 °C. Experimental results revealed distinctive differences in localized thermal conductivity, which suggests the use of approximated or constant property values is expected to bring about results with largely inflated uncertainties when investigating bio-heat transfer mechanisms and/or performing sophisticated thermal modeling with complex biological tissues. Overall, the presented micro thermal sensor with automated data analysis algorithm is a promising approach for direct thermal conductivity measurement of aqueous solutions and soft biomaterials and is of great value to cryopreservation of tissues, hyperthermia or cryogenic, and other thermal-based clinical diagnostics and treatments. PMID:25993037

Characteristics of heat transfer and fluid flow in a channel with single-row plates array oblique to flow direction for photovoltaic/thermal system

International Nuclear Information System (INIS)

Ali, Ahmed Hamza H.; Ahmed, Mahmoud; Youssef, M.S.

2010-01-01

This study has been carried out to investigate the characteristics of convective heat transfer and fluid flow for a single row of oblique plates array to the flow direction inside a channel. The flow inside the channel is laminar and the plates array have spanwise distance between the plates and heated by radiation. This configuration has been designed to be used for Photovoltaic/Thermal system (PV/T) applications. The theoretical results are validated with measured values, and a good agreement prevailed. The results show that an increase in the plate oblique angle (γ) in the range from 0 to 15 degrees, leads to an increase in the Nusselt number (Nu) up to a maximum value and then decreases. The oblique angle at the maximum value of Nu depends on the flow Reynolds Number (Re), and (l w /l pl ), where (l w /l pl ) is defined as the ratio of the plates' spacing at zero oblique angle to the plate length. Furthermore, increasing (l w /l pl ) results in a significant increase in the heat transfer coefficient depending on the values of Re, and plate oblique angle (γ). In addition, increasing (γ) from 0 to 15 degrees results in a decrease in the friction factor up to a certain value, after which the friction value approaches a constant value depending on Re value and (l w /l pl ). It was found that for any value of the plate oblique angle (γ), the friction factor decreases with the increase of the values of (l w /l pl ) and Re, respectively.

MISSION-ORIENTED SENSOR ARRAYS AND UAVs – A CASE STUDY ON ENVIRONMENTAL MONITORING

Directory of Open Access Journals (Sweden)

N. M. Figueira

2015-08-01

Full Text Available This paper presents a new concept of UAV mission design in geomatics, applied to the generation of thematic maps for a multitude of civilian and military applications. We discuss the architecture of Mission-Oriented Sensors Arrays (MOSA, proposed in Figueira et Al. (2013, aimed at splitting and decoupling the mission-oriented part of the system (non safety-critical hardware and software from the aircraft control systems (safety-critical. As a case study, we present an environmental monitoring application for the automatic generation of thematic maps to track gunshot activity in conservation areas. The MOSA modeled for this application integrates information from a thermal camera and an on-the-ground microphone array. The use of microphone arrays technology is of particular interest in this paper. These arrays allow estimation of the direction-of-arrival (DOA of the incoming sound waves. Information about events of interest is obtained by the fusion of the data provided by the microphone array, captured by the UAV, fused with information from the termal image processing. Preliminary results show the feasibility of the on-the-ground sound processing array and the simulation of the main processing module, to be embedded into an UAV in a future work. The main contributions of this paper are the proposed MOSA system, including concepts, models and architecture.

Hydrokinesitherapy in thermal mineral water

Directory of Open Access Journals (Sweden)

Rendulić-Slivar Senka

2013-01-01

Full Text Available The treatment of clients in health spa resorts entails various forms of hydrotherapy. Due to specific properties of water, especially thermal mineral waters, hydrokinesitherapy has a positive effect on the locomotor system, aerobic capabilities of organism and overall quality of human life. The effects of use of water in movement therapy are related to the physical and chemical properties of water. The application of hydrotherapy entails precautionary measures, with an individual approach in assessment and prescription. The benefits of treatment in thermal mineral water should be emphasized and protected, as all thermal mineral waters differ in composition. All physical properties of water are more pronounced in thermal mineral waters due to its mineralisation, hence its therapeutical efficiency is greater, as well.

Damage Detection/Locating System Providing Thermal Protection

Science.gov (United States)

Woodard, Stanley E. (Inventor); Jones, Thomas W. (Inventor); Taylor, Bryant D. (Inventor); Qamar, A. Shams (Inventor)

2010-01-01

A damage locating system also provides thermal protection. An array of sensors substantially tiles an area of interest. Each sensor is a reflective-surface conductor having operatively coupled inductance and capacitance. A magnetic field response recorder is provided to interrogate each sensor before and after a damage condition. Changes in response are indicative of damage and a corresponding location thereof.

Intracellular Protein Delivery and Gene Transfection by Electroporation Using a Microneedle Electrode Array

Science.gov (United States)

Choi, Seong-O; Kim, Yeu-Chun; Lee, Jeong Woo; Park, Jung-Hwan

2012-01-01

The impact of many biopharmaceuticals, including protein- and gene-based therapies, has been limited by the need for better methods of delivery into cells within tissues. Here, we present intracellular delivery of molecules and transfection with plasmid DNA by electroporation using a novel microneedle electrode array designed for targeted treatment of skin and other tissue surfaces. The microneedle array is molded out of polylactic acid. Electrodes and circuitry required for electroporation are applied to the microneedle array surface by a new metal-transfer micromolding method. The microneedle array maintains mechanical integrity after insertion into pig cadaver skin and is able to electroporate human prostate cancer cells in vitro. Quantitative measurements show that increasing electroporation pulse voltage increases uptake efficiency of calcein and bovine serum albumin, whereas increasing pulse length has lesser effects over the range studied. Uptake of molecules by up to 50 % of cells and transfection of 12 % of cells with a gene for green fluorescent protein is demonstrated at high cell viability. We conclude that the microneedle electrode array is able to electroporate cells, resulting in intracellular uptake of molecules, and has potential applications to improve intracellular delivery of proteins, DNA and other biopharmaceuticals. PMID:22328093

Design and fabrication of two-dimensional semiconducting bolometer arrays for HAWC and SHARC-II

Science.gov (United States)

Voellmer, George M.; Allen, Christine A.; Amato, Michael J.; Babu, Sachidananda R.; Bartels, Arlin E.; Benford, Dominic J.; Derro, Rebecca J.; Dowell, C. D.; Harper, D. A.; Jhabvala, Murzy D.; Moseley, S. H.; Rennick, Timothy; Shirron, Peter J.; Smith, W. W.; Staguhn, Johannes G.

2003-02-01

The High resolution Airborne Wideband Camera (HAWC) and the Submillimeter High Angular Resolution Camera II (SHARC II) will use almost identical versions of an ion-implanted silicon bolometer array developed at the National Aeronautics and Space Administration's Goddard Space Flight Center (GSFC). The GSFC "Pop-Up" Detectors (PUD's) use a unique folding technique to enable a 12 × 32-element close-packed array of bolometers with a filling factor greater than 95 percent. A kinematic Kevlar suspension system isolates the 200 mK bolometers from the helium bath temperature, and GSFC - developed silicon bridge chips make electrical connection to the bolometers, while maintaining thermal isolation. The JFET preamps operate at 120 K. Providing good thermal heat sinking for these, and keeping their conduction and radiation from reaching the nearby bolometers, is one of the principal design challenges encountered. Another interesting challenge is the preparation of the silicon bolometers. They are manufactured in 32-element, planar rows using Micro Electro Mechanical Systems (MEMS) semiconductor etching techniques, and then cut and folded onto a ceramic bar. Optical alignment using specialized jigs ensures their uniformity and correct placement. The rows are then stacked to create the 12 × 32-element array. Engineering results from the first light run of SHARC II at the Caltech Submillimeter Observatory (CSO) are presented.

Synthesis and Investigation of Millimeter-Scale Vertically Aligned Boron Nitride Nanotube Arrays

Science.gov (United States)

Tay, Roland; Li, Hongling; Tsang, Siu Hon; Jing, Lin; Tan, Dunlin; Teo, Edwin Hang Tong

Boron nitride nanotubes (BNNTs) have shown potential in a wide range of applications due to their superior properties such as exceptionally high mechanical strength, excellent chemical and thermal stabilities. However, previously reported methods to date only produced BNNTs with limited length/density and insufficient yield at high temperatures. Here we present a facile and effective two-step synthesis route involving template-assisted chemical vapor deposition at a relatively low temperature of 900 degree C and subsequent annealing process to fabricate vertically aligned (VA) BN coated carbon nanotube (VA-BN/CNT) and VA-BNNT arrays. By using this method, we achieve the longest VA-BN/CNTs and VA-BNNTs to date with lengths of over millimeters (exceeding two orders of magnitude longer than the previously reported length of VA-BNNTs). In addition, the morphology, chemical composition and microstructure of the resulting products, as well as the mechanism of coating process are systematically investigated. This versatile BN coating technique and the synthesis of millimeter-scale BN/CNT and BNNT arrays pave a way for new applications especially where the aligned geometry of the NTs is essential such as for field-emission, interconnects and thermal management.

Implementation of the first student-designed PV array in Canada

International Nuclear Information System (INIS)

Hadlock, C.; DeLoyde, J.; Dhir, T.

2004-01-01

This paper is a culmination of a 2-year project involving students, faculty, staff member, and private industry. Solar Technology Education Project (STEP) became the first student-led group to successfully install a 36-panel photovoltaic (PV) array on a Canadian University campus. The fundraising, design, and assembly of the PV array was entirely student driven. The project was completed in January 2004 with the installation of a 2 kW photovoltaic grid-tied array mounted to the roof of the University of Waterloo's Federation Hall, the largest student-run pub in North America. The photovoltaic array was a demonstration project to raise awareness about solar technology and the need for energy efficiency in buildings. It took two years to complete the project, which was implemented in three phases. The first phase was aimed at raising the required capital. The second phase included design and fabrication of the array. The third phase, still ongoing today, is the community outreach phase, which involves educating the surrounding communities about the project, solar technology, and the role of individuals in combating global warming. This paper examines the steps required for the implementation of a successful educational photovoltaic project, using the students' experience as a roadmap. A section highlighting what's next for STEP is also presented as the students attempt to build on the momentum from the project. The aim is to launch a solar thermal project on another University of Waterloo building to move one step closer to the ultimate goal of a sustainable campus

Fabrication of a bubble-driven arrayed actuator for a tactile display

International Nuclear Information System (INIS)

Shikida, Mitsuhiro; Imamura, Tsubasa; Ukai, Shinji; Miyaji, Takaaki; Sato, Kazuo

2008-01-01

A chip-sized arrayed actuator device has been developed for application to a tactile display. Each actuator uses a liquid–vapour phase change to drive a microneedle that stimulates receptors in a finger in contact with the array. The actuators have a flexible diaphragm structure and a bottom plate bonded together to create a cavity between them. A microneedle and a microheater are formed on the diaphragm and plate of each actuator, respectively. The sealed cavity is filled with an operating liquid. Activating the heater and generating bubbles, which is similar to the process of a thermal ink jet, increase the pressure in the cavity. As a result, the flexible membrane deforms and it drives the needle upwards to stimulate receptors. Microelectromechanical systems technologies are used to fabricate the three components of the actuators, which are manually assembled to form a 3 × 3 arrayed actuator device. The total size of the device is 15 × 15 × 1 mm. The device performance is experimentally evaluated and a large needle displacement (61 µm) is obtained with an input energy of 457 mJ

Charged particle therapy with mini-segmented beams

Directory of Open Access Journals (Sweden)

F. Avraham eDilmanian

2015-12-01

Full Text Available One of the fundamental attributes of proton therapy and carbon ion therapy is the ability of these charged particles to spare tissue distal to the targeted tumor. This significantly reduces normal tissue toxicity and has the potential to translate to a wider therapeutic index. Although, in general, particle therapy also reduces dose to the proximal tissues, particularly in the vicinity of the target, dose to the skin and to other very superficial tissues tends to be higher than that of megavoltage x-rays. The methods presented here, namely Interleaved carbon minibeams and Radiosurgery with arrays of proton and light ion minibeams, both utilize beams segmented into arrays of parallel minibeams of about 0.3 mm incident beam size. These minibeam arrays spare tissues, as demonstrated by synchrotron x-ray experiments. An additional feature of particle minibeams is their gradual broadening due to multiple Coulomb scattering as they penetrate tissues. In the case of interleaved carbon minibeams, which do not broaden much, two arrays of planar carbon minibeams that remain parallel at target depth, are aimed at the target from 90º angles and made to interleave at the target to produce a solid radiation field within the target. As a result the surrounding tissues are exposed only to individual carbon minibeam arrays and are therefore spared. The method was used in four-directional geometry at the NASA Space Radiation Laboratory to ablate a 6.5-mm target in a rabbit brain at a single exposure with 40 Gy physical absorbed dose. Contrast-enhanced magnetic resonance imaging and histology six month later showed very focal target necrosis with nearly no damage to the surrounding brain. As for minibeams of protons and light ions, for which the minibeam broadening is substantial, measurements at MD Anderson Cancer Center in Houston, Texas, and Monte Carlo simulations showed that the broadening minibeams will merge with their neighbors at a certain tissue depth

Coupling in reflector arrays

DEFF Research Database (Denmark)

Appel-Hansen, Jørgen

1968-01-01

In order to reduce the space occupied by a reflector array, it is desirable to arrange the array antennas as close to each other as possible; however, in this case coupling between the array antennas will reduce the reflecting properties of the reflector array. The purpose of the present communic......In order to reduce the space occupied by a reflector array, it is desirable to arrange the array antennas as close to each other as possible; however, in this case coupling between the array antennas will reduce the reflecting properties of the reflector array. The purpose of the present...

Intracranial dual-mode IVUS and hyperthermia using circular arrays: preliminary experiments.

Science.gov (United States)

Patel, Vivek; Light, Edward; Herickhoff, Carl; Grant, Gerald; Britz, Gavin; Wilson, Christy; Palmeri, Mark; Smith, Stephen

2013-01-01

In this study, we investigated the feasibility of using 3.5-Fr (3 Fr = 1 mm) circular phased-array intravascular ultrasound (IVUS) catheters for minimally invasive, image-guided hyperthermia treatment of tumors in the brain. Feasibility was demonstrated in two ways: (1) by inserting a 3.5-Fr IVUS catheter through skull burr holes, for 20 MHz brain imaging in the pig model, and (2) by testing a modified circular array for therapy potential with 18.5-MHz and 9-MHz continuous wave (CW) excitation. The imaging transducer's performance was superior to our previous 9-MHz mechanical IVUS prototype. The therapy catheter transducer was driven by CW electrical power at 18.5 MHz, achieving temperature changes reaching +8°C at a depth of 2 mm in a human glioblastoma grown on the flank of a mouse with minimal transducer resistive heating of +2°C. Further hyperthermia trials showed that 9-MHz CW excitation produced temperature changes of +4.5°C at a depth of 12 mm-a sufficient temperature rise for our long-term goal of targeted, controlled drug release via thermosensitive liposomes for therapeutic treatment of 1-cm-diameter glioblastomas.

Non-Destructive Spent Fuel Characterization with Semiconducting Gallium Arsinde Neutron Imaging Arrays

International Nuclear Information System (INIS)

McGregor, Douglas S.; Gersch, Holly K.; Sanders, Jeffrey D.; Lee, John C.; Hammig, Mark D.; Hartman, Michael R.; Yong Hong Yang; Klann, Raymond T.; Elzen, Brian Van Der; Lindsay, John T.; Simpson, Philip A.

2002-01-01

High resistivity bulk grown GaAs has been used to produce thermal neutron imaging devices for use in neutron radiography and characterizing burnup in spent fuel. The basic scheme utilizes a portable Sb/Be source for monoenergetic (24 keV) neutron radiation source coupled to an Fe filter with a radiation hard B-coated pixellated GaAs detector array as the primary neutron detector. The coated neutron detectors have been tested for efficiency and radiation hardness in order to determine their fitness for the harsh environments imposed by spent fuel. Theoretical and experimental results are presented, showing detector radiation hardness, expected detection efficiency and the spatial resolution from such a scheme. A variety of advanced neutron detector designs have been explored, with experimental results achieving 13% thermal neutron detection efficiency while projecting the possibility of over 30% thermal neutron detection efficiency

Nanomanipulation of 2 inch wafer fabrication of vertically aligned carbon nanotube arrays by nanoimprint lithography

DEFF Research Database (Denmark)

Bu, Ian Y. Y.; Eichhorn, Volkmar; Carlson, Kenneth

2011-01-01

Carbon nanotube (CNT) arrays are typically defined by electron beam lithography (EBL), and hence limited to small areas due to the low throughput. To obtain wafer‐scale fabrication we propose large area thermal nanoimprint lithography (NIL). A 2‐inch stamp master is defined using EBL for subsequent......, efficient production of wafer‐scale/larger arrays of CNTs has been achieved. The CNTs have been deposited by wafer‐scale plasma enhanced chemical vapour deposition (PECVD) of C2H2/NH3. Substrates containing such nanotubes have been used to automate nanorobotic manipulation sequences of individual CNTs...

High-density arrays of x-ray microcalorimeters for Constellation-X

Science.gov (United States)

Kilbourne, Caroline A.; Bandler, Simon R.; Brown, Ari D.; Chervenak, James A.; Figueroa-Feliciano, Enectali; Finkbeiner, Fred M.; Iyomoto, Naoko; Kelley, Richard L.; Porter, F. Scott; Saab, Tarek; Sadleir, John; White, Jennifer

2006-06-01

We have been developing x-ray microcalorimeters for the Constellation-X mission. Devices based on superconducting transition-edge sensors (TES) have demonstrated the potential to meet the Constellation-X requirements for spectral resolution, speed, and array scale (> 1000 pixels) in a close-packed geometry. In our part of the GSFC/NIST collaboration on this technology development, we have been concentrating on the fabrication of arrays of pixels suitable for the Constellation-X reference configuration. We have fabricated 8x8 arrays with 0.25-mm pixels arranged with 92% fill factor. The pixels are based on Mo/Au TES and Bi/Cu or Au/Bi absorbers. We have achieved a resolution of 4.0 eV FWHM at 6 keV in such devices, which meets the Constellation-X resolution requirement at 6 keV. Studies of the thermal transport in our Bi/Cu absorbers have shown that, while there is room for improvement, for 0.25-mm pixels the standard absorber design is adequate to avoid unacceptable line-broadening from position dependence caused by thermal diffusion. In order to improve reproducibility and to push closer to the 2-eV goal at 6 keV, however, we are refining the design of the TES and the interface to the absorber. Recent efforts to introduce a barrier layer between the Bi and the Mo/Au to avoid variable interface chemistry and thus improve the reproducibility of device characteristics have thus far yielded unsatisfactory results. However, we have developed a new set of absorber designs with contacts to the TES engineered to allow contact only in regions that do not serve as the active thermometer. We have further constrained the design so that a low-resistance absorber will not electrically short the TES. It is with such a design that we have achieved 4.0 eV resolution at 6 keV.

A novel, flat, electronically-steered phased array transducer for tissue ablation: preliminary results

International Nuclear Information System (INIS)

Ellens, Nicholas P K; Lucht, Benjamin B C; Gunaseelan, Samuel T; Hudson, John M; Hynynen, Kullervo H

2015-01-01

Flat, λ/2-spaced phased arrays for therapeutic ultrasound were examined in silico and in vitro. All arrays were made by combining modules made of 64 square elements with 1.5 mm inter-element spacing along both major axes. The arrays were designed to accommodate integrated, co-aligned diagnostic transducers for targeting and monitoring. Six arrays of 1024 elements (16 modules) and four arrays of 6144 elements (96 modules) were modelled and compared according to metrics such as peak pressure amplitude, focal size, ability to be electronically-steered far off-axis and grating lobe amplitude. Two 1024 element prototypes were built and measured in vitro, producing over 100 W of acoustic power. In both cases, the simulation model of the pressure amplitude field was in good agreement with values measured by hydrophone. Using one of the arrays, it was shown that the peak pressure amplitude dropped by only 24% and 25% of the on-axis peak pressure amplitude when steered to the edge of the array (40 mm) at depths of 30 mm and 50 mm. For the 6144 element arrays studied in in silico only, similarly high steerability was found: even when steered 100 mm off-axis, the pressure amplitude decrease at the focus was less than 20%, while the maximum pressure grating lobe was only 20%. Thermal simulations indicate that the modules produce more than enough acoustic power to perform rapid ablations at physiologically relevant depths and steering angles. Arrays such as proposed and tested in this study have enormous potential: their high electronic steerability suggests that they will be able to perform ablations of large volumes without the need for any mechanical translation. (paper)

K-West and K-East basin thermal analyses for dry conditions

International Nuclear Information System (INIS)

Beaver, T.R.; Cramer, E.R.; Hinman, C.A.

1994-01-01

Detailed 3 dimensional thermal analyses of the 100K East and 100 K West basins were conducted to determine the peak fuel temperature for intact fuel in the event of a complete loss of water from the basins. Thermal models for the building, an array of fuel encapsulation canisters on the basin floor, and the fuel within a single canister are described along with conservative predictions for the maximum expected temperatures for the loss of water event

Experimental and Numerical Investigations in Shallow Cut Grinding by Workpiece Integrated Infrared Thermopile Array.

Science.gov (United States)

Reimers, Marcel; Lang, Walter; Dumstorff, Gerrit

2017-09-30

The purpose of our study is to investigate the heat distribution and the occurring temperatures during grinding. Therefore, we did both experimental and numerical investigations. In the first part, we present the integration of an infrared thermopile array in a steel workpiece. Experiments are done by acquiring data from the thermopile array during grinding of a groove in a workpiece made of steel. In the second part, we present numerical investigations in the grinding process to further understand the thermal characteristic during grinding. Finally, we conclude our work. Increasing the feed speed leads to two things: higher heat flux densities in the workpiece and higher temperature gradients in the material.

Dosimetric characterization of a 2-D array of 223 solid state detectors for daily morning checks in Tomo Therapy equipment

International Nuclear Information System (INIS)

Reyes S, U.; Sosa A, M.; Vega C, H. R.

2015-10-01

Tomo Therapy is a new technique for the cancer treatment; however, the equipment must meet nearly all mechanical and dosimetric characteristics of a conventional linear accelerator for medical use. Daily quality controls are vital to the good operation of the equipment and thus guarantee excellent quality in the daily delivery of treatments. This paper presents the procedure of the dosimetric characterization of a two-dimensional array of 223 solid state detectors, called TomoDose of the Sun Nuclear Company. Dosimetric important criteria are established to perform these checks quickly and accurately. Dosimetric tests proposed are: repeatability, linearity, dependence of Sad and SSD. Some results are compared with readings of the ionization chamber Exradim A1SL. Finally the results of 30 consecutive days are presented to establish criteria for evidence of dose, field size, symmetry and flattening of the radiation beam on Tomo Therapy equipment. Expected values for daily verification are: Dose constancy of 194.89 c Gy, σ= 1.31 c Gy, symmetry in the X axis of -0.19 %, σ=0.08 %, symmetry in the Y axis of 1.66 %, σ= 0.05 %, flattened in the X axis of 25.71 %, σ= 0.05 % and flattened in the Y axis of 6.41 %, σ= 10.23 %. Field sizes obtained were 40.45 cm in the X axis and 5.10 on the Y axis, with standard deviations of 0.02 cm and 0.01 cm, respectively. TomoDose dosimetric values, compared to the values obtained with ionization chamber, presented differences smaller than 2%. (Author)

SU-E-J-91: Novel Epitaxial Silicon Array for Quality Assurance in Photon and Proton Therapy

International Nuclear Information System (INIS)

Talamonti, C; Zani, M; Scaringella, M; Bruzzi, M; Bucciolini, M; Menichelli, D; Friedl, F

2014-01-01

Purpose: to demonstrate suitability of a novel silicon array for measuring the dose properties of highly conformal photon and proton beams. Methods: prototype under test is a 24cm long linear array prototype, although the underlying technology is suitable to construct 2D arrays as well. It is based on a 64pixels monolithic sensor with 1mm pixel pitch, made of epitaxial ptype silicon. Thanks to design modularity, more sensors can be placed side by side without breaking pixel pitch. Flattened and unflattened photon beams, as well as proton radiation from a cyclotron in pencil beam scanning mode, were considered. Measurements of beam characteristics as percentage depth doses, dose profiles, output factors and energy response, which are necessary to deliver radiation with high precision and reliability, were performed. Results: Dose rate independence with photons was verified in the dose per pulse range 0.03 to 2mGy. Results clearly indicate nondependence of the detector sensitivity both for flattened and unflattened beams, with a variation of at most 0.5percentage. OFs were obtained for field with a lateral size ranging from 0.8cm to 16cm and the results are in good agreement with ion chamber A1SL, max difference less than 1.5percentage. Field sizes and beam penumbra were measured and compared to EBT film results. Concerning proton beams, sensitivity independence on dose rate was verified by changing the beam current in the interval 2-130Gy/s. Field sizes and beam penumbra measurements are in agreement with data taken with a scintillating 2D array with 0.5mm resolution IBA Lynx, and a better penumbra definition than an array of ionization chambers IBA MatriXX is reached. Conclusion: The device is a novel and valuable tool for QA both for photon and proton dose delivery. All measurements demonstrated its capability to measure with high spatial resolution many crucial properties of the RT beam

SU-E-J-91: Novel Epitaxial Silicon Array for Quality Assurance in Photon and Proton Therapy

Energy Technology Data Exchange (ETDEWEB)

Talamonti, C; Zani, M; Scaringella, M; Bruzzi, M; Bucciolini, M [University of Florence, Firenze (Italy); Menichelli, D; Friedl, F [IBA Dosimetry, Schwarzenbruck, Bavaria (Germany)

2014-06-01

Purpose: to demonstrate suitability of a novel silicon array for measuring the dose properties of highly conformal photon and proton beams. Methods: prototype under test is a 24cm long linear array prototype, although the underlying technology is suitable to construct 2D arrays as well. It is based on a 64pixels monolithic sensor with 1mm pixel pitch, made of epitaxial ptype silicon. Thanks to design modularity, more sensors can be placed side by side without breaking pixel pitch. Flattened and unflattened photon beams, as well as proton radiation from a cyclotron in pencil beam scanning mode, were considered. Measurements of beam characteristics as percentage depth doses, dose profiles, output factors and energy response, which are necessary to deliver radiation with high precision and reliability, were performed. Results: Dose rate independence with photons was verified in the dose per pulse range 0.03 to 2mGy. Results clearly indicate nondependence of the detector sensitivity both for flattened and unflattened beams, with a variation of at most 0.5percentage. OFs were obtained for field with a lateral size ranging from 0.8cm to 16cm and the results are in good agreement with ion chamber A1SL, max difference less than 1.5percentage. Field sizes and beam penumbra were measured and compared to EBT film results. Concerning proton beams, sensitivity independence on dose rate was verified by changing the beam current in the interval 2-130Gy/s. Field sizes and beam penumbra measurements are in agreement with data taken with a scintillating 2D array with 0.5mm resolution IBA Lynx, and a better penumbra definition than an array of ionization chambers IBA MatriXX is reached. Conclusion: The device is a novel and valuable tool for QA both for photon and proton dose delivery. All measurements demonstrated its capability to measure with high spatial resolution many crucial properties of the RT beam.

Concurrent array-based queue

Science.gov (United States)

Heidelberger, Philip; Steinmacher-Burow, Burkhard

2015-01-06

According to one embodiment, a method for implementing an array-based queue in memory of a memory system that includes a controller includes configuring, in the memory, metadata of the array-based queue. The configuring comprises defining, in metadata, an array start location in the memory for the array-based queue, defining, in the metadata, an array size for the array-based queue, defining, in the metadata, a queue top for the array-based queue and defining, in the metadata, a queue bottom for the array-based queue. The method also includes the controller serving a request for an operation on the queue, the request providing the location in the memory of the metadata of the queue.

A Multi-Modality CMOS Sensor Array for Cell-Based Assay and Drug Screening.

Science.gov (United States)

Chi, Taiyun; Park, Jong Seok; Butts, Jessica C; Hookway, Tracy A; Su, Amy; Zhu, Chengjie; Styczynski, Mark P; McDevitt, Todd C; Wang, Hua

2015-12-01

In this paper, we present a fully integrated multi-modality CMOS cellular sensor array with four sensing modalities to characterize different cell physiological responses, including extracellular voltage recording, cellular impedance mapping, optical detection with shadow imaging and bioluminescence sensing, and thermal monitoring. The sensor array consists of nine parallel pixel groups and nine corresponding signal conditioning blocks. Each pixel group comprises one temperature sensor and 16 tri-modality sensor pixels, while each tri-modality sensor pixel can be independently configured for extracellular voltage recording, cellular impedance measurement (voltage excitation/current sensing), and optical detection. This sensor array supports multi-modality cellular sensing at the pixel level, which enables holistic cell characterization and joint-modality physiological monitoring on the same cellular sample with a pixel resolution of 80 μm × 100 μm. Comprehensive biological experiments with different living cell samples demonstrate the functionality and benefit of the proposed multi-modality sensing in cell-based assay and drug screening.

Analysis of thermal-dose response to heat

International Nuclear Information System (INIS)

Storm, F.; Roe, D.; Drury, B.

1987-01-01

The authors reasoned that if hyperthermia alone has a clinical anti-tumor effect, response should have a thermal dose relationship. The authors analyzed 100 patients with advanced cancer treated with magnetic-induction. Three methods of determining thermal dose were used: (A) t1x10, the lowest temperature sustained throughout the tumor for 30-60min during the first of ten daily treatments, which represents one usual course of ten hourly sessions; (B) t43 (equivalent minutes at 43C) which accounts for non-linear tumor heating by combining serially measured temperatures during the first treatment with a mathematical description of the time-temperature relationship for thermal inactivation or damage; (C) Ct43 (cumulative t43), which represents the t43 value multiplied by the actual number of subsequent daily treatments received. Response was defined as CR+PR+MR. The results show a statistically significant effect of heat alone for t1x10, t43, and Ct43. These analyses demonstrate a thermal-dose relationship between hyperthermia therapy and tumor response as a sole independent variable, which indicates that heat therapy has clinical anti-cancer activity

Interface thermal characteristics of flip chip packages - A numerical study

International Nuclear Information System (INIS)

Kandasamy, Ravi; Mujumdar, A.S.

2009-01-01

Flip chip ball grid array (FC-BGA) packages are commonly used for high inputs/outputs (I/O) ICs; they have been proven to provide good solutions for a variety of applications to maximize thermal and electrical performance. A fundamental limitation to such devices is the thermal resistance at the top of the package, which is characterized θ JC parameter. The die-to-lid interface thermal resistance is identified as a critical issue for the thermal management of electronic packages. This paper focuses on the effect of the interface material property changes on the interface thermal resistance. The effect of package's junction to case (Theta-JC or θ JC ) thermal performance is investigated for bare die, flat lid and cup lid packages using a validated thermal model. Thermal performance of a cup or flat lid attached and bare die packages were investigated for different interface materials. Improved Theta-JC performance was observed for the large die as compared to the smaller die. Several parametric studies were carried out to understand the effects of interface bond line thickness (BLT), different die sizes, the average void size during assembly and thermal conductivity of interface materials on package thermal resistance

[Clinical observation of post-herpetic neuralgia treated with TCM herbal cupping therapy].

Science.gov (United States)

Wu, Xi; Hu, Hui; Guo, Liang; Wang, Hui

2013-02-01

To compare the difference in the efficacy on post-herpetic neuralgia among TCM herbal cupping therapy, Chinese medicine thermal compressing therapy and mecobalamine. Fifty-seven cases were randomized into a TCM herbal cupping group, a thermal compressing group and a western medicine group, 19 cases in each one. The oral administration of ibuprofen was applied in every group. In the herbal cupping group, the bamboo cups soaked in the boiled Chinese herbal decoction were sucked on the most significant painful area. In the thermal compressing group, the towel soaked in the boiled Chinese herbal decoction was compressed on the most significant painful area. In the medication group, the muscular injection of mecobalamine was adopted. The treatment was given once a day, for 2 weeks totally in each group. SF-MPQ score and clinical efficacy before and after treatment were observed in each group. The remarkable effective rates were 78.9% (15/19), 36.8% (7/19) and 5.3% (1/19) in the TCM herbal cupping group, thermal compressing group and western medicine group separately. The efficacy in the TCM herbal cupping group was significantly superior to the thermal compressing group and western medicine group (all P cupping group was reduced more significantly as compared with the thermal compressing group and western medicine group (all P cupping therapy achieves the superior efficacy for post-herpetic neuralgia and relieves pain effectively of the patients, which is more advantageous than CM herbal thermal compressing therapy and Mecobalamine.

Effect of density variation and non-covalent functionalization on the compressive behavior of carbon nanotube arrays

Energy Technology Data Exchange (ETDEWEB)

Misra, A [Instrumentation and Applied Physics, Indian Institute of Science, Bangalore, 560012 (India); Raney, J R; Craig, A E; Daraio, C, E-mail: daraio@caltech.edu [Engineering and Applied Science, California Institute of Technology, Pasadena, CA 91125 (United States)

2011-10-21

Arrays of aligned carbon nanotubes (CNTs) have been proposed for different applications, including electrochemical energy storage and shock-absorbing materials. Understanding their mechanical response, in relation to their structural characteristics, is important for tailoring the synthesis method to the different operational conditions of the material. In this paper, we grow vertically aligned CNT arrays using a thermal chemical vapor deposition system, and we study the effects of precursor flow on the structural and mechanical properties of the CNT arrays. We show that the CNT growth process is inhomogeneous along the direction of the precursor flow, resulting in varying bulk density at different points on the growth substrate. We also study the effects of non-covalent functionalization of the CNTs after growth, using surfactant and nanoparticles, to vary the effective bulk density and structural arrangement of the arrays. We find that the stiffness and peak stress of the materials increase approximately linearly with increasing bulk density.

Novel iron oxide nanotube arrays as high-performance anodes for lithium ion batteries

Science.gov (United States)

Zhong, Yuan; Fan, Huiqing; Chang, Ling; Shao, Haibo; Wang, Jianming; Zhang, Jianqing; Cao, Chu-nan

2015-11-01

Nanostructured iron oxides can be promising anode materials for lithium ion batteries (LIBs). However, improvement on the rate capability and/or electrochemical cycling stability of iron oxide anode materials remains a key challenge because of their poor electrical conductivities and large volume expansion during cycling. Herein, the vertically aligned arrays of one-dimensional (1D) iron oxide nanotubes with 5.8 wt% carbon have been fabricated by a novel surfactant-free self-corrosion process and subsequent thermal treatment. The as-fabricated nanotube array electrode delivers a reversible capacity of 932 mAh g-1 after 50 charge-discharge cycles at a current of 0.6 A g-1. The electrode still shows a reversible capacity of 610 mAh g-1 even at a very high rate (8.0 A g-1), demonstrating its prominent rate capability. Furthermore, the nanotube array electrode also exhibits the excellent electrochemical cycling stability with a reversible capacity of 880 mAh g-1 after 500 cycles at a current of 4 A g-1. The nanotube array electrode with superior lithium storage performance reveals the promising potential as a high-performance anode for LIBs.

Optoacoustic detection of thermal lesions

Science.gov (United States)

Arsenault, Michel G.; Kolios, Michael C.; Whelan, William M.

2009-02-01

Minimally invasive thermal therapy is being investigated as an alternative cancer treatment. It involves heating tissues to greater than 55°C over a period of a few minutes, which results in tissue coagulation. Optoacoustic (OA) imaging is a new imaging technique that involves exposing tissues to pulsed light and detecting the acoustic waves that are generated. In this study, adult bovine liver tissue samples were heated using continuous wave laser energy for various times, then scanned using an optoacoustic imaging system. Large optoacoustic signal variability was observed in the native tissue prior to heating. OA signal amplitude increased with maximum tissue temperature achieved, characterized by a correlation coefficient of 0.63. In this study we show that there are detectable changes in optoacoustic signal strength that arise from tissue coagulation, which demonstrates the potential of optoacoustic technology for the monitoring of thermal therapy delivery.

Characteristics of heat transfer and fluid flow in a channel with single-row plates array oblique to flow direction for photovoltaic/thermal system

Energy Technology Data Exchange (ETDEWEB)

Ali, Ahmed Hamza H. [Department of Energy Resources and Environmental Engineering, Egypt-Japan University of Science and Technology (E-JUST), P.O. Box 179, New Borg El-Arab City, Alexandria 21934 (Egypt); Ahmed, Mahmoud; Youssef, M.S. [Department of Mechanical Engineering, Faculty of Engineering, Assiut University, Assiut 71516 (Egypt)

2010-09-15

This study has been carried out to investigate the characteristics of convective heat transfer and fluid flow for a single row of oblique plates array to the flow direction inside a channel. The flow inside the channel is laminar and the plates array have spanwise distance between the plates and heated by radiation. This configuration has been designed to be used for Photovoltaic/Thermal system (PV/T) applications. The theoretical results are validated with measured values, and a good agreement prevailed. The results show that an increase in the plate oblique angle ({gamma}) in the range from 0 to 15 degrees, leads to an increase in the Nusselt number (Nu) up to a maximum value and then decreases. The oblique angle at the maximum value of Nu depends on the flow Reynolds Number (Re), and (l{sub w}/l{sub pl}), where (l{sub w}/l{sub pl}) is defined as the ratio of the plates' spacing at zero oblique angle to the plate length. Furthermore, increasing (l{sub w}/l{sub pl}) results in a significant increase in the heat transfer coefficient depending on the values of Re, and plate oblique angle ({gamma}). In addition, increasing ({gamma}) from 0 to 15 degrees results in a decrease in the friction factor up to a certain value, after which the friction value approaches a constant value depending on Re value and (l{sub w}/l{sub pl}). It was found that for any value of the plate oblique angle ({gamma}), the friction factor decreases with the increase of the values of (l{sub w}/l{sub pl}) and Re, respectively. (author)

IMPROVED COMPUTATIONAL CHARACTERIZATION OF THE THERMAL NEUTRON SOURCE FOR NEUTRON CAPTURE THERAPY RESEARCH AT THE UNIVERSITY OF MISSOURI

Energy Technology Data Exchange (ETDEWEB)

Stuart R. Slattery; David W. Nigg; John D. Brockman; M. Frederick Hawthorne

2010-05-01

Parameter studies, design calculations and initial neutronic performance measurements have been completed for a new thermal neutron beamline to be used for neutron capture therapy cell and small-animal radiobiology studies at the University of Missouri Research Reactor. The beamline features the use of single-crystal silicon and bismuth sections for neutron filtering and for reduction of incident gamma radiation. The computational models used for the final beam design and performance evaluation are based on coupled discrete-ordinates and Monte Carlo techniques that permit detailed modeling of the neutron transmission properties of the filtering crystals with very few approximations. This is essential for detailed dosimetric studies required for the anticipated research program.

Programmable cellular arrays. Faults testing and correcting in cellular arrays

International Nuclear Information System (INIS)

Cercel, L.

1978-03-01

A review of some recent researches about programmable cellular arrays in computing and digital processing of information systems is presented, and includes both combinational and sequential arrays, with full arbitrary behaviour, or which can realize better implementations of specialized blocks as: arithmetic units, counters, comparators, control systems, memory blocks, etc. Also, the paper presents applications of cellular arrays in microprogramming, in implementing of a specialized computer for matrix operations, in modeling of universal computing systems. The last section deals with problems of fault testing and correcting in cellular arrays. (author)

In vivo photothermal treatment with real-time monitoring by optical fiber-needle array.

Science.gov (United States)

Yang, Taeseok Daniel; Park, Kwanjun; Kim, Hyung-Jin; Im, Nu-Ri; Kim, Byoungjae; Kim, TaeHoon; Seo, Sohyun; Lee, Jae-Seung; Kim, Beop-Min; Choi, Youngwoon; Baek, Seung-Kuk

2017-07-01

Photothermal treatment (PTT) using gold nanoshells (gold-NSs) is accepted as a method for treating cancer. However, owing to restrictions in therapeutic depth and skin damage caused by excessive light exposure, its application has been limited to lesions close to the epidermis. Here, we demonstrate an in vivo PTT method that uses gold-NSs with a flexible optical fiber-needle array (OFNA), which is an array of multiple needles in which multimode optical fibers are inserted, one in each, for light delivery. The light for PTT was directly administrated to subcutaneous tissues through the OFNA, causing negligible thermal damage to the skin. Enhancement of light energy delivery assisted by the OFNA in a target area was confirmed by investigation using artificial tissues. The ability of OFNA to treat cancer without causing cutaneous thermal damage was also verified by hematoxylin and eosin (H&E) staining and optical coherence tomography in cancer models in mice. In addition, the OFNA allowed for observation of the target site through an imaging fiber bundle. By imaging the activation of the injected gold-NSs, we were able to obtain information on the PTT process in real-time.

Long-term lumen depreciation behavior and failure modes of multi-die array LEDs

Science.gov (United States)

Jayawardena, Asiri; Marcus, Daniel; Prugue, Ximena; Narendran, Nadarajah

2013-09-01

One of the main advantages of multi-die array light-emitting diodes (LEDs) is their high flux density. However, a challenge for using such a product in lighting fixture applications is the heat density and the need for thermal management to keep the junction temperatures of all the dies low for long-term reliable performance. Ten multi-die LED array samples for each product from four different manufacturers were subjected to lumen maintenance testing (as described in IES-LM-80-08), and their resulting lumen depreciation and failure modes were studied. The products were tested at the maximum case (or pin) temperature reported by the respective manufacturer by appropriately powering the LEDs. In addition, three samples for each product from two different manufacturers were subjected to rapid thermal cycling, and the resulting lumen depreciation and failure modes were studied. The results showed that the exponential lumen decay model using long-term lumen maintenance data as recommended in IES TM-21 does not fit for all package types. The failure of a string of dies and single die failure in a string were observed in some of the packages.

A random phased array device for delivery of high intensity focused ultrasound.

Science.gov (United States)

Hand, J W; Shaw, A; Sadhoo, N; Rajagopal, S; Dickinson, R J; Gavrilov, L R

2009-10-07

Randomized phased arrays can offer electronic steering of a single focus and simultaneous multiple foci concomitant with low levels of secondary maxima and are potentially useful as sources of high intensity focused ultrasound (HIFU). This work describes laboratory testing of a 1 MHz random phased array consisting of 254 elements on a spherical shell of radius of curvature 130 mm and diameter 170 mm. Acoustic output power and efficiency are measured for a range of input electrical powers, and field distributions for various single- and multiple-focus conditions are evaluated by a novel technique using an infrared camera to provide rapid imaging of temperature changes on the surface of an absorbing target. Experimental results show that the array can steer a single focus laterally to at least +/-15 mm off axis and axially to more than +/-15 mm from the centre of curvature of the array and patterns of four and five simultaneous foci +/-10 mm laterally and axially whilst maintaining low intensity levels in secondary maxima away from the targeted area in good agreement with linear theoretical predictions. Experiments in which pork meat was thermally ablated indicate that contiguous lesions several cm(3) in volume can be produced using the patterns of multiple foci.

A random phased array device for delivery of high intensity focused ultrasound

International Nuclear Information System (INIS)

Hand, J W; Shaw, A; Sadhoo, N; Rajagopal, S; Dickinson, R J; Gavrilov, L R

2009-01-01

Randomized phased arrays can offer electronic steering of a single focus and simultaneous multiple foci concomitant with low levels of secondary maxima and are potentially useful as sources of high intensity focused ultrasound (HIFU). This work describes laboratory testing of a 1 MHz random phased array consisting of 254 elements on a spherical shell of radius of curvature 130 mm and diameter 170 mm. Acoustic output power and efficiency are measured for a range of input electrical powers, and field distributions for various single- and multiple-focus conditions are evaluated by a novel technique using an infrared camera to provide rapid imaging of temperature changes on the surface of an absorbing target. Experimental results show that the array can steer a single focus laterally to at least ±15 mm off axis and axially to more than ±15 mm from the centre of curvature of the array and patterns of four and five simultaneous foci ±10 mm laterally and axially whilst maintaining low intensity levels in secondary maxima away from the targeted area in good agreement with linear theoretical predictions. Experiments in which pork meat was thermally ablated indicate that contiguous lesions several cm 3 in volume can be produced using the patterns of multiple foci.

Frontiers of Radio Astronomy in the 2020s: The Next Generation Very Large Array

Science.gov (United States)

Murphy, Eric Joseph; ngVLA Project Office, ngVLA Science and Technical Advisory Councils, ngVLA Science Working Groups

2018-01-01

This talk will describe the current community-driven science goals, design, and planning status of a future large centimeter radio array: the ‘Next Generation Very Large Array’ (ngVLA). The ngVLA is being developed to observe at wavelengths between ALMA at submm wavelengths, and the future SKA-1 at few centimeter and longer wavelengths, opening a new window on the Universe through ultra-sensitive imaging of thermal line and continuum emission down to milliarcsecond resolution, and unprecedented broad band continuum polarimetric imaging of non-thermal processes. The current design for the array includes 10x more effective collecting area and 10x higher spatial resolution than the current JVLA or ALMA, carefully optimized for operation in the frequency range 10GHz to 50GHz, while still delivering world-leading sensitivity over the entire 1.2GHz to 116 GHz spectrum.With this array, new frontiers in modern astronomy can be reached, including direct imaging and chemical analysis of planet formation in the terrestrial-zone of nearby stars, studies of dust-obscured star formation and the cosmic baryon cycle down to pc-scales in the local Universe, and detailed imaging of molecular gas and galaxy formation into the epoch of reionization. Novel techniques for exploring temporal phenomena on timescales from milliseconds to years will also be implemented. The ngVLA will be situated in the desert southwest of the United States, centered on the current JVLA infrastructure, with multiple antennas anticipated in states/regions adjacent to NM, and in northern Mexico.A recently formed Project Office is working closely with the U.S. and international research community to design the array, and plan its construction beginning mid next decade. Recent significant funding for design and development brought forward by the NSF will enable detailed science case development and technology prototyping/risk reduction before the next U.S astronomy Decadal Survey.

Thermally switchable adhesions of polystyrene-block-poly(n-isopropylacrylamide) copolymer pillar array mimicking climb attitude of geckos

Science.gov (United States)

Chen, Jem-Kun; Wang, Jing-Hong; Chang, Jia-Yaw; Fan, Shih-Kang

2012-09-01

Inspired by the gecko foot pad, we fabricated polystyrene-block-poly(N-isopropylacrylamide) (PS-b-PNIPAAm) copolymer pillar array to mimic climbing attitude of a gecko, alternately attach to and detach from a surface. The pillar array structure of the PS segment significantly enhances both of the hydrophilic and hydrophobic property of PNIPAAm segment tips at 25 and 50 °C, respectively, which could generate alternating adhesive forces of approximately 120 and 11 nN. The dramatic change in adhesive and friction force difference at 25 and 50 °C may guide the design of bio-inspired artificial analogues, which could approach gecko's climbing behavior.

Performance and costs of a roof-sized PV/thermal array combined with a ground coupled heat pump

NARCIS (Netherlands)

Bakker, M.; Zondag, H.A.

2005-01-01

A photovoltaic/thermal (PVT) panel is a combination of photovoltaic cells with a solar thermal collector, generating solar electricity and solar heat simultaneously. Hence, PVT panels are an alternative for a combination of separate PV panels and solar thermal collectors. A promising system concept,

In vitro radiobiological evaluation of selective killing effects of 10B1-paraboronophenylalanine.HCl in the thermal neutron capture therapy of malignant melanoma cells

International Nuclear Information System (INIS)

Ichihashi, M.; Ueda, M.; Hayashibe, K.; Hatta, S.; Tsuji, M.; Mishima, Y.; Fukuda, H.; Kobayashi, T.; Kanda, K.

1985-01-01

In order to clarify the specific affinity of 10 B 1 -p-boronophenylalanine.HCl ( 10 B 1 -BPA) to melanoma cells, the killing effects of 10 B 1 -BPA in the thermal neutron capture treatment on both cultured melanotic and amelanotic melanoma cells were compared with those on non-melanoma cells, such as Alexander cells, HeLa cells and normal human fibroblasts. Cells in the plateau phase cultured in the usual medium for 4-7 days were incubated with the medium containing 50 μg/ml 10 B 1 -BPA for 20 hours until 2 hours before thermal neutron irradiation. After thermal neutron irradiation, the number of colonies consisting of more than 50 cells was counted to obtain the dose-survival curves. The melanotic cells pre-incubated with 10 B 1 -BPA had more enhanced killing sensitivity to thermal neutron irradiation than amelanotic melanoma cells pre-incubated similarly with 10 B 1 -BPA. 10 B 1 -BPA pre-incubation had no enhanced killing effects on Alexander cells, but had slightly enhanced killing effects on HeLa cells. These results indicate that 10 B 1 -BPA could be incorporated by a specific uptake mechanism of melanoma cells and accumulated within melanotic melanoma cells and that 10 B 1 -BPA at present could be the best chemical for the thermal neutron capture therapy of human malignant melanoma. (Namekawa, K.)

Experimental and Numerical Investigations in Shallow Cut Grinding by Workpiece Integrated Infrared Thermopile Array

Directory of Open Access Journals (Sweden)

Marcel Reimers

2017-09-01

Full Text Available The purpose of our study is to investigate the heat distribution and the occurring temperatures during grinding. Therefore, we did both experimental and numerical investigations. In the first part, we present the integration of an infrared thermopile array in a steel workpiece. Experiments are done by acquiring data from the thermopile array during grinding of a groove in a workpiece made of steel. In the second part, we present numerical investigations in the grinding process to further understand the thermal characteristic during grinding. Finally, we conclude our work. Increasing the feed speed leads to two things: higher heat flux densities in the workpiece and higher temperature gradients in the material.

New Genetic Insights and Therapy in Multiple Myeloma

NARCIS (Netherlands)

K.L. Wu

2007-01-01

textabstractIn the last decade, several significant advances in myeloma therapy have occurred with the pace of change accelerated with the introduction of new anti-myeloma agents. The approach to the treatment of multiple myeloma has become more complex with an array of therapeutic options,

Acoustic and thermal properties of tissue

Science.gov (United States)

Retat, L.; Rivens, I.; ter Haar, G. R.

2012-10-01

Differences in ultrasound (US) and thermal properties of abdominal soft tissues may affect the delivery of thermal therapies such as high intensity focused ultrasound and may provide a basis for US monitoring of such therapies. 21 rat livers were obtained, within one hour of surgical removal. For a single liver, 3 lobes were selected and each treated in one of 3 ways: maintained at room temperature, water bath heated to 50°C ± 1°C for 10 ± 0.5 minutes, or water bath heated to 60°C ± 1°C for 10 ± 0.6 minutes. The attenuation coefficient, speed of sound and thermal conductivity of fresh rat liver was measured. The attenuation coefficients and speed of sound were measured using the finite-amplitude insertion-substitution (FAIS) method. For each rat liver, the control and treated lobes were scanned using a pair of weakly focused 2.5 MHz Imasonic transducers over the range 1.8 to 3 MHz. The conductivity measurement apparatus was designed to provide one-dimensional heat flow through each specimen using a combination of insulation, heat source and heat sink. Using 35 MHz US images to determine the volume of air trapped in the system, the thermal conductivity was corrected using a simulation based on the Helmhotz bio-heat equation. The process of correlating these results with biological properties is discussed.

Cyclotron-Resonance-Maser Arrays

International Nuclear Information System (INIS)

Kesar, A.; Lei, L.; Dikhtyar, V.; Korol, M.; Jerby, E.

1999-01-01

The cyclotron-resonance-maser (CRM) array [1] is a radiation source which consists of CRM elements coupled together under a common magnetic field. Each CRM-element employs a low-energy electron-beam which performs a cyclotron interaction with the local electromagnetic wave. These waves can be coupled together among the CRM elements, hence the interaction is coherently synchronized in the entire array. The implementation of the CRM-array approach may alleviate several technological difficulties which impede the development of single-beam gyro-devices. Furthermore, it proposes new features, such as the phased-array antenna incorporated in the CRM-array itself. The CRM-array studies may lead to the development of compact, high-power radiation sources operating at low-voltages. This paper introduces new conceptual schemes of CRM-arrays, and presents the progress in related theoretical and experimental studies in our laboratory. These include a multi-mode analysis of a CRM-array, and a first operation of this device with five carbon-fiber cathodes

Degree-of-Freedom Strengthened Cascade Array for DOD-DOA Estimation in MIMO Array Systems.

Science.gov (United States)

Yao, Bobin; Dong, Zhi; Zhang, Weile; Wang, Wei; Wu, Qisheng

2018-05-14

In spatial spectrum estimation, difference co-array can provide extra degrees-of-freedom (DOFs) for promoting parameter identifiability and parameter estimation accuracy. For the sake of acquiring as more DOFs as possible with a given number of physical sensors, we herein design a novel sensor array geometry named cascade array. This structure is generated by systematically connecting a uniform linear array (ULA) and a non-uniform linear array, and can provide more DOFs than some exist array structures but less than the upper-bound indicated by minimum redundant array (MRA). We further apply this cascade array into multiple input multiple output (MIMO) array systems, and propose a novel joint direction of departure (DOD) and direction of arrival (DOA) estimation algorithm, which is based on a reduced-dimensional weighted subspace fitting technique. The algorithm is angle auto-paired and computationally efficient. Theoretical analysis and numerical simulations prove the advantages and effectiveness of the proposed array structure and the related algorithm.

Infrared detectors, focal plane arrays, and imaging sensors; Proceedings of the Meeting, Orlando, FL, Mar. 30, 31, 1989

Science.gov (United States)

Dereniak, Eustace L.; Sampson, Robert T.

1989-10-01

The present conference on advancements in IR detectors, Schottky-barrier focal plane arrays, CCD image analysis, and HgCdTe materials gives attention to a 256 x 256 PtSi array for IR astronomy, proposals for a second-generation meteosat's advanced optical payload, cryogenic bipolar technology for on-focal-plane signal processing, a parallel cellular processing system for fast generation of perspective plots, and ultrahigh-speed CCD image sensors for scanning applications. Also discussed are MBE GaAs rib waveguide experiments at 10.6 microns, an interferometric thermal detector, the development status of superconducting IR detector research, the absorption coefficients of n-type Hg(1-x)Cd(x)Te samples, and the influence of the surface channel on crosstalk in HgCdTe photovoltaic arrays.

Molecular Dynamics Simulation of High Density DNA Arrays

Directory of Open Access Journals (Sweden)

Rudolf Podgornik

2018-01-01

Full Text Available Densely packed DNA arrays exhibit hexagonal and orthorhombic local packings, as well as a weakly first order transition between them. While we have some understanding of the interactions between DNA molecules in aqueous ionic solutions, the structural details of its ordered phases and the mechanism governing the respective phase transitions between them remains less well understood. Since at high DNA densities, i.e., small interaxial spacings, one can neither neglect the atomic details of the interacting macromolecular surfaces nor the atomic details of the intervening ionic solution, the atomistic resolution is a sine qua non to properly describe and analyze the interactions between DNA molecules. In fact, in order to properly understand the details of the observed osmotic equation of state, one needs to implement multiple levels of organization, spanning the range from the molecular order of DNA itself, the possible ordering of counterions, and then all the way to the induced molecular ordering of the aqueous solvent, all coupled together by electrostatic, steric, thermal and direct hydrogen-bonding interactions. Multiscale simulations therefore appear as singularly suited to connect the microscopic details of this system with its macroscopic thermodynamic behavior. We review the details of the simulation of dense atomistically resolved DNA arrays with different packing symmetries and the ensuing osmotic equation of state obtained by enclosing a DNA array in a monovalent salt and multivalent (spermidine counterions within a solvent permeable membrane, mimicking the behavior of DNA arrays subjected to external osmotic stress. By varying the DNA density, the local packing symmetry, and the counterion type, we are able to analyze the osmotic equation of state together with the full structural characterization of the DNA subphase, the counterion distribution and the solvent structural order in terms of its different order parameters and

High thermoelectric properties of (Sb, Bi)2Te3 nanowire arrays by tilt-structure engineering

Science.gov (United States)

Tan, Ming; Hao, Yanming; Deng, Yuan; Chen, Jingyi

2018-06-01

In this paper, we present an innovative tilt-structure design concept for (Sb, Bi)2Te3 nanowire array assembled by high-quality nanowires with well oriented growth, utilizing a simple vacuum thermal evaporation technique. The unusual tilt-structure (Sb, Bi)2Te3 nanowire array with a tilted angle of 45° exhibits a high thermoelectric dimensionless figure-of-merit ZT = 1.72 at room temperature. The relatively high ZT value in contrast to that of previously reported (Sb, Bi)2Te3 materials and the vertical (Sb, Bi)2Te3 nanowire arrays evidently reveals the crucial role of the unique tilt-structure in favorably influencing carrier and phonon transport properties, resulting in a significantly improved ZT value. The transport mechanism of such tilt-structure is proposed and investigated. This method opens a new approach to optimize nano-structure in thin films for next-generation thermoelectric materials and devices.

A review of array radars

Science.gov (United States)

Brookner, E.

1981-10-01

Achievements in the area of array radars are illustrated by such activities as the operational deployment of the large high-power, high-range-resolution Cobra Dane; the operational deployment of two all-solid-state high-power, large UHF Pave Paws radars; and the development of the SAM multifunction Patriot radar. This paper reviews the following topics: array radars steered in azimuth and elevation by phase shifting (phase-phase steered arrays); arrays steered + or - 60 deg, limited scan arrays, hemispherical coverage, and omnidirectional coverage arrays; array radars steering electronically in only one dimension, either by frequency or by phase steering; and array radar antennas which use no electronic scanning but instead use array antennas for achieving low antenna sidelobes.

Performance assessment of a 2D array of plastic scintillation detectors for IMRT quality assurance

Science.gov (United States)

Guillot, Mathieu; Gingras, Luc; Archambault, Louis; Beddar, Sam; Beaulieu, Luc

2013-07-01

The purposes of this work are to assess the performance of a 2D plastic scintillation detectors array prototype for quality assurance in intensity-modulated radiation therapy (IMRT) and to determine its sensitivity and specificity to positioning errors of one multileaf collimator (MLC) leaf and one MLC leaf bank by applying the principles of signal detection theory. Ten treatment plans (step-and-shoot delivery) and one volumetric modulated arc therapy plan were measured and compared to calculations from two treatment-planning systems (TPSs) and to radiochromic films. The averages gamma passing rates per beam found for the step-and-shoot plans were 95.8% for the criteria (3%, 2 mm), 97.8% for the criteria (4%, 2 mm), and 98.1% for the criteria (3%, 3 mm) when measurements were compared to TPS calculations. The receiver operating characteristic curves for the one leaf errors and one leaf bank errors were determined from simulations (theoretical upper limits) and measurements. This work concludes that arrays of plastic scintillation detectors could be used for IMRT quality assurance in clinics. The use of signal detection theory could improve the quality of dosimetric verifications in radiation therapy by providing optimal discrimination criteria for the detection of different classes of errors.

Performance assessment of a 2D array of plastic scintillation detectors for IMRT quality assurance

International Nuclear Information System (INIS)

Guillot, Mathieu; Gingras, Luc; Archambault, Louis; Beaulieu, Luc; Beddar, Sam

2013-01-01

The purposes of this work are to assess the performance of a 2D plastic scintillation detectors array prototype for quality assurance in intensity-modulated radiation therapy (IMRT) and to determine its sensitivity and specificity to positioning errors of one multileaf collimator (MLC) leaf and one MLC leaf bank by applying the principles of signal detection theory. Ten treatment plans (step-and-shoot delivery) and one volumetric modulated arc therapy plan were measured and compared to calculations from two treatment-planning systems (TPSs) and to radiochromic films. The averages gamma passing rates per beam found for the step-and-shoot plans were 95.8% for the criteria (3%, 2 mm), 97.8% for the criteria (4%, 2 mm), and 98.1% for the criteria (3%, 3 mm) when measurements were compared to TPS calculations. The receiver operating characteristic curves for the one leaf errors and one leaf bank errors were determined from simulations (theoretical upper limits) and measurements. This work concludes that arrays of plastic scintillation detectors could be used for IMRT quality assurance in clinics. The use of signal detection theory could improve the quality of dosimetric verifications in radiation therapy by providing optimal discrimination criteria for the detection of different classes of errors. (paper)

Neutron capture therapy with thermal neutrons at IRT MIFI

International Nuclear Information System (INIS)

Zajtsev, K.N.; Portnov, A.A.; Savkin, V.A.; Kulakov, V.N.; Khokhlov, V.F.; Shejno, I.N.; Vajnson, A.A.; Kozlovskaya, N.G.; Meshcherikova, V.V.; Mitin, V.N.; Yarmonenko, S.P.

2001-01-01

Combined preclinical investigations into neutron capture therapy are conducted. Malignant melanoma was adopted as the line of investigation; boron-containing and gadolinium-containing preparations were used during the neutron capture therapy working off. Preparations produce secondary varying radiations when used in tumor. Dogs with spontaneous melanoma were used for the experiments. Procedures for the irradiation of dogs by neutron beam as the stage before use for the treatment of oncology patients were finished off; efficiency of neutron beam influence on normal tissues during the irradiation of dogs with melanoma (and without it) in antitumor and side effect sense was estimated [ru

Thermally optimum spacing of vertical, natural convection cooled, parallel plates

Science.gov (United States)

Bar-Cohen, A.; Rohsenow, W. M.

Vertical two-dimensional channels formed by parallel plates or fins are a frequently encountered configuration in natural convection cooling in air of electronic equipment. In connection with the complexity of heat dissipation in vertical parallel plate arrays, little theoretical effort is devoted to thermal optimization of the relevant packaging configurations. The present investigation is concerned with the establishment of an analytical structure for analyses of such arrays, giving attention to useful relations for heat distribution patterns. The limiting relations for fully-developed laminar flow, in a symmetric isothermal or isoflux channel as well as in a channel with an insulated wall, are derived by use of a straightforward integral formulation.

Formation of patterned arrays of Au nanoparticles on SiC surface by template confined dewetting of normal and oblique deposited nanoscale films

Energy Technology Data Exchange (ETDEWEB)

Ruffino, F., E-mail: francesco.ruffino@ct.infn.it; Grimaldi, M.G.

2013-06-01

We report on the formation of patterned arrays of Au nanoparticles (NPs) on 6H SiC surface. To this end, we exploit the thermal-induced dewetting properties of a template confined deposited nanoscale Au film. In this approach, the Au surface pattern order, on the SiC substrate, is established by a template confined deposition using a micrometric template. Then, a dewetting process of the patterned Au film is induced by thermal processes. We compare the results, about the patterns formation, obtained for normal and oblique deposited Au films. We show that the normal and oblique depositions, through the same template, originate different patterns of the Au film. As a consequence of these different starting patterns, after the thermal processes, different patterns for the arrays of NPs originating from the dewetting mechanisms are obtained. For each fixed deposition angle α, the pattern evolution is analyzed, by scanning electron microscopy, as a function of the annealing time at 1173 K (900 °C). From these analyses, quantitative evaluations on the NPs size evolution are drawn. - Highlights: • Micrometric template-confined nanoscale gold films are deposited on silicon carbide. • The dewetting process of template-confined gold films on silicon carbide is studied. • Comparison of dewetting process of normal and oblique deposited gold films is drawn. • Patterned arrays of gold nanoparticles on silicon carbide surface are produced.

Formation of patterned arrays of Au nanoparticles on SiC surface by template confined dewetting of normal and oblique deposited nanoscale films

International Nuclear Information System (INIS)

Ruffino, F.; Grimaldi, M.G.

2013-01-01

We report on the formation of patterned arrays of Au nanoparticles (NPs) on 6H SiC surface. To this end, we exploit the thermal-induced dewetting properties of a template confined deposited nanoscale Au film. In this approach, the Au surface pattern order, on the SiC substrate, is established by a template confined deposition using a micrometric template. Then, a dewetting process of the patterned Au film is induced by thermal processes. We compare the results, about the patterns formation, obtained for normal and oblique deposited Au films. We show that the normal and oblique depositions, through the same template, originate different patterns of the Au film. As a consequence of these different starting patterns, after the thermal processes, different patterns for the arrays of NPs originating from the dewetting mechanisms are obtained. For each fixed deposition angle α, the pattern evolution is analyzed, by scanning electron microscopy, as a function of the annealing time at 1173 K (900 °C). From these analyses, quantitative evaluations on the NPs size evolution are drawn. - Highlights: • Micrometric template-confined nanoscale gold films are deposited on silicon carbide. • The dewetting process of template-confined gold films on silicon carbide is studied. • Comparison of dewetting process of normal and oblique deposited gold films is drawn. • Patterned arrays of gold nanoparticles on silicon carbide surface are produced

Finite-element analysis of elastic sound-proof coupling thermal state

Science.gov (United States)

Tsyss, V. G.; Strokov, I. M.; Sergaeva, M. Yu

2018-01-01

The aim is in calculated determining of the elastic rubber-metal element thermal state of soundproof coupling ship shafting under variable influence during loads in time. Thermal coupling calculation is performed with finite element method using NX Simens software with Nastran solver. As a result of studies, the following results were obtained: - a volumetric picture of the temperature distribution over the array of the deformed coupling body is obtained; - time to reach steady-state thermal coupling mode has been determined; - dependences of maximum temperature and time to reach state on the established operation mode on rotation frequency and ambient temperature are determined. The findings prove the conclusion that usage of finite element analysis modern software can significantly speed up problem solving.

The EUROBALL array

International Nuclear Information System (INIS)

Rossi Alvarez, C.

1998-01-01

The quality of the multidetector array EUROBALL is described, with emphasis on the history and formal organization of the related European collaboration. The detector layout is presented together with the electronics and Data Acquisition capabilities. The status of the instrument, its performances and the main features of some recently developed ancillary detectors will also be described. The EUROBALL array is operational in Legnaro National Laboratory (Italy) since April 1997 and is expected to run up to November 1998. The array represents a significant improvement in detector efficiency and sensitivity with respect to the previous generation of multidetector arrays

Dosimetry boron neutron capture therapy in liver cancer (hepatocellular carcinoma) by means of MCNP-code with neutron source from thermal column

International Nuclear Information System (INIS)

Irhas; Andang Widi Harto; Yohannes Sardjono

2014-01-01

Boron Neutron Capture Therapy (BNCT) using physics principle when B 10 (Boron-10) irradiated by low energy neutron (thermal neutron). Boron and thermal neutron reaction produced B 11m (Boron-11m) (t 1/2 =10 -2 s). B 11m decay emitted alpha, Li 7 (Lithium-7) particle and gamma ray. Irradiated time needed to ensure cancer dose enough. Liver cancer was primary malignant who located in liver (Hepatocellular carcinoma). Malignant in liver were different to metastatic from Breast, Colon Cancer, and the other. This condition was Metastatic Liver Cancer. Monte Carlo method used by Monte Carlo N-Particle (MCNP) Software. Probabilistic approach used for probability of interaction occurred and record refers to characteristic of particle and material. In this case, thermal neutron produced by model of Collimated Thermal Column Kartini Research Nuclear Reactor, Yogyakarta. Modelling organ and source used liver organ that contain of cancer tissue and research reactor. Variation of boron concentration was 20, 25, 30, 35, 40, 45, and 47 µg/g cancers. Output of MCNP calculation were neutron scattering dose, gamma ray dose and neutron flux from reactor. Neutron flux used to calculate alpha, proton and gamma ray dose from interaction of tissue material and thermal neutron. Variation of boron concentration result dose rate to every variation were 0,059; 0,072; 0,084; 0,098; 0.108; 0,12; 0,125 Gy/sec. Irradiation time who need to every concentration were 841,5 see (14 min 1 sec); 696,07 sec(11 min 36 sec); 593.11 sec (9 min 53 sec); 461,35 sec (8 min 30 sec); 461,238 sec (7 min 41 sec); 414,23 sec (6 min 54 sec); 398,38 sec (6 min 38 sec). Irradiating time could shortly when boron concentration more high. (author)

The analysis and rationale behind the upgrading of existing standard definition thermal imagers to high definition

Science.gov (United States)

Goss, Tristan M.

2016-05-01

With 640x512 pixel format IR detector arrays having been on the market for the past decade, Standard Definition (SD) thermal imaging sensors have been developed and deployed across the world. Now with 1280x1024 pixel format IR detector arrays becoming readily available designers of thermal imager systems face new challenges as pixel sizes reduce and the demand and applications for High Definition (HD) thermal imaging sensors increases. In many instances the upgrading of existing under-sampled SD thermal imaging sensors into more optimally sampled or oversampled HD thermal imaging sensors provides a more cost effective and reduced time to market option than to design and develop a completely new sensor. This paper presents the analysis and rationale behind the selection of the best suited HD pixel format MWIR detector for the upgrade of an existing SD thermal imaging sensor to a higher performing HD thermal imaging sensor. Several commercially available and "soon to be" commercially available HD small pixel IR detector options are included as part of the analysis and are considered for this upgrade. The impact the proposed detectors have on the sensor's overall sensitivity, noise and resolution is analyzed, and the improved range performance is predicted. Furthermore with reduced dark currents due to the smaller pixel sizes, the candidate HD MWIR detectors are operated at higher temperatures when compared to their SD predecessors. Therefore, as an additional constraint and as a design goal, the feasibility of achieving upgraded performance without any increase in the size, weight and power consumption of the thermal imager is discussed herein.

D Surface Generation from Aerial Thermal Imagery

Science.gov (United States)

Khodaei, B.; Samadzadegan, F.; Dadras Javan, F.; Hasani, H.

2015-12-01

Aerial thermal imagery has been recently applied to quantitative analysis of several scenes. For the mapping purpose based on aerial thermal imagery, high accuracy photogrammetric process is necessary. However, due to low geometric resolution and low contrast of thermal imaging sensors, there are some challenges in precise 3D measurement of objects. In this paper the potential of thermal video in 3D surface generation is evaluated. In the pre-processing step, thermal camera is geometrically calibrated using a calibration grid based on emissivity differences between the background and the targets. Then, Digital Surface Model (DSM) generation from thermal video imagery is performed in four steps. Initially, frames are extracted from video, then tie points are generated by Scale-Invariant Feature Transform (SIFT) algorithm. Bundle adjustment is then applied and the camera position and orientation parameters are determined. Finally, multi-resolution dense image matching algorithm is used to create 3D point cloud of the scene. Potential of the proposed method is evaluated based on thermal imaging cover an industrial area. The thermal camera has 640×480 Uncooled Focal Plane Array (UFPA) sensor, equipped with a 25 mm lens which mounted in the Unmanned Aerial Vehicle (UAV). The obtained results show the comparable accuracy of 3D model generated based on thermal images with respect to DSM generated from visible images, however thermal based DSM is somehow smoother with lower level of texture. Comparing the generated DSM with the 9 measured GCPs in the area shows the Root Mean Square Error (RMSE) value is smaller than 5 decimetres in both X and Y directions and 1.6 meters for the Z direction.

Comparison of parameters of modern cooled and uncooled thermal cameras

Science.gov (United States)

Bareła, Jarosław; Kastek, Mariusz; Firmanty, Krzysztof; Krupiński, Michał

2017-10-01

During the design of a system employing thermal cameras one always faces a problem of choosing the camera types best suited for the task. In many cases such a choice is far from optimal one, and there are several reasons for that. System designers often favor tried and tested solution they are used to. They do not follow the latest developments in the field of infrared technology and sometimes their choices are based on prejudice and not on facts. The paper presents the results of measurements of basic parameters of MWIR and LWIR thermal cameras, carried out in a specialized testing laboratory. The measured parameters are decisive in terms of image quality generated by thermal cameras. All measurements were conducted according to current procedures and standards. However the camera settings were not optimized for a specific test conditions or parameter measurements. Instead the real settings used in normal camera operations were applied to obtain realistic camera performance figures. For example there were significant differences between measured values of noise parameters and catalogue data provided by manufacturers, due to the application of edge detection filters to increase detection and recognition ranges. The purpose of this paper is to provide help in choosing the optimal thermal camera for particular application, answering the question whether to opt for cheaper microbolometer device or apply slightly better (in terms of specifications) yet more expensive cooled unit. Measurements and analysis were performed by qualified personnel with several dozen years of experience in both designing and testing of thermal camera systems with both cooled and uncooled focal plane arrays. Cameras of similar array sizes and optics were compared, and for each tested group the best performing devices were selected.

Silicon Micromachined Microlens Array for THz Antennas

Science.gov (United States)

Lee, Choonsup; Chattopadhyay, Goutam; Mehdi, IImran; Gill, John J.; Jung-Kubiak, Cecile D.; Llombart, Nuria

2013-01-01

5 5 silicon microlens array was developed using a silicon micromachining technique for a silicon-based THz antenna array. The feature of the silicon micromachining technique enables one to microfabricate an unlimited number of microlens arrays at one time with good uniformity on a silicon wafer. This technique will resolve one of the key issues in building a THz camera, which is to integrate antennas in a detector array. The conventional approach of building single-pixel receivers and stacking them to form a multi-pixel receiver is not suited at THz because a single-pixel receiver already has difficulty fitting into mass, volume, and power budgets, especially in space applications. In this proposed technique, one has controllability on both diameter and curvature of a silicon microlens. First of all, the diameter of microlens depends on how thick photoresist one could coat and pattern. So far, the diameter of a 6- mm photoresist microlens with 400 m in height has been successfully microfabricated. Based on current researchers experiences, a diameter larger than 1-cm photoresist microlens array would be feasible. In order to control the curvature of the microlens, the following process variables could be used: 1. Amount of photoresist: It determines the curvature of the photoresist microlens. Since the photoresist lens is transferred onto the silicon substrate, it will directly control the curvature of the silicon microlens. 2. Etching selectivity between photoresist and silicon: The photoresist microlens is formed by thermal reflow. In order to transfer the exact photoresist curvature onto silicon, there needs to be etching selectivity of 1:1 between silicon and photoresist. However, by varying the etching selectivity, one could control the curvature of the silicon microlens. The figure shows the microfabricated silicon microlens 5 x5 array. The diameter of the microlens located in the center is about 2.5 mm. The measured 3-D profile of the microlens surface has a

Thin randomly aligned hierarchical carbon nanotube arrays as ultrablack metamaterials

Science.gov (United States)

De Nicola, Francesco; Hines, Peter; De Crescenzi, Maurizio; Motta, Nunzio

2017-07-01

Ultrablack metamaterials are artificial materials able to harvest all the incident light regardless of wavelength, angle, or polarization. Here, we show the ultrablack properties of randomly aligned hierarchical carbon nanotube arrays with thicknesses below 200 nm. The thin coatings are realized by solution processing and dry-transfer deposition on different substrates. The hierarchical surface morphology of the coatings is biomimetic and provides a large effective area that improves the film optical absorption. Also, such a morphology is responsible for the moth-eye effect, which leads to the omnidirectional and polarization-independent suppression of optical reflection. The films exhibit an emissivity up to 99.36% typical of an ideal black body, resulting in the thinnest ultrablack metamaterial ever reported. Such a material may be exploited for thermal, optical, and optoelectronic devices such as heat sinks, optical shields, solar cells, light and thermal sensors, and light-emitting diodes.

Storage array reflection considerations

International Nuclear Information System (INIS)

Haire, M.J.; Jordan, W.C.; Taylor, R.G.

1997-01-01

The assumptions used for reflection conditions of single containers are fairly well established and consistently applied throughout the industry in nuclear criticality safety evaluations. Containers are usually considered to be either fully water reflected (i.e., surrounded by 6 to 12 in. of water) for safety calculations or reflected by 1 in. of water for nominal (structural material and air) conditions. Tables and figures are usually available for performing comparative evaluations of containers under various loading conditions. Reflection considerations used for evaluating the safety of storage arrays of fissile material are not as well established. When evaluating arrays, it has become more common for analysts to use calculations to demonstrate the safety of the array configuration. In performing these calculations, the analyst has considerable freedom concerning the assumptions made for modeling the reflection of the array. Considerations are given for the physical layout of the array with little or no discussion (or demonstration) of what conditions are bounded by the assumed reflection conditions. For example, an array may be generically evaluated by placing it in a corner of a room in which the opposing walls are far away. Typically, it is believed that complete flooding of the room is incredible, so the array is evaluated for various levels of water mist interspersed among array containers. This paper discusses some assumptions that are made regarding storage array reflection

Cascading Constrained 2-D Arrays using Periodic Merging Arrays

DEFF Research Database (Denmark)

Forchhammer, Søren; Laursen, Torben Vaarby

2003-01-01

We consider a method for designing 2-D constrained codes by cascading finite width arrays using predefined finite width periodic merging arrays. This provides a constructive lower bound on the capacity of the 2-D constrained code. Examples include symmetric RLL and density constrained codes...

Testing of focal plane arrays

International Nuclear Information System (INIS)

Merriam, J.D.

1988-01-01

Problems associated with the testing of focal plane arrays are briefly examined with reference to the instrumentation and measurement procedures. In particular, the approach and instrumentation used as the Naval Ocean Systems Center is presented. Most of the measurements are made with flooded illumination on the focal plane array. The array is treated as an ensemble of individual pixels, data being taken on each pixel and array averages and standard deviations computed for the entire array. Data maps are generated, showing the pixel data in the proper spatial position on the array and the array statistics

Monitoring daily and sub-daily variations in crustal strain with seismic arrays

Science.gov (United States)

Mao, S.; Campillo, M.; van der Hilst, R. D.; Brenguier, F.; Hillers, G.

2017-12-01

We demonstrate that we can monitor deformation of the shallow crust (with hourly temporal resolution) directly with seismic waves, by measuring relative seismic wave speed changes (dv/v) due to relatively known periodical forcing (tides and changes in atmospheric temperature) at Piton de la Fournaise Volcano (PdF), La Réunion. We use ambient seismic noise recorded (for one month) at VolcArray, an experiment with three arrays of 49 vertical-component geophones deployed on a 7x7 grid of approximately 80 m spacing. Through noise-based coda wave interferometry we infer for each array the average relative changes in propagation speed of seismic waves (dv/v) as a function of time, which relate to temporal changes in medium properties within 100m depth. The variations in dv/v ( 0.05%) on time-scales longer than a day are best explained by effects of precipitation on pore pressure. In contrast, the (weaker) daily and sub-daily fluctuations of dv/v ( 0.01%) are likely to be caused by tidal and thermal effects. We verify that the inferred variations of dv/v are unrelated to spatiotemporal changes of noise wavefields. We further compare the power spectrum of dv/v with spectra of simulated tide-induced volumetric strain, temperature records, very broadband (VBB) seismograms, and borehole tilt records. In all five types of data, dominant peaks are found at around diurnal, semi-diurnal, and ter-diurnal frequencies. A comparison of phase and spectra of the data suggests that the tidal and thermal effects on dv/v are of similar magnitude but vary with frequency. Theoretical modeling of tide- and temperature-induced strain in different frequency bands agrees with the relative magnitude of the two effects on dv/v from passive monitoring.

Dense Vertically Aligned Copper Nanowire Composites as High Performance Thermal Interface Materials.

Science.gov (United States)

Barako, Michael T; Isaacson, Scott G; Lian, Feifei; Pop, Eric; Dauskardt, Reinhold H; Goodson, Kenneth E; Tice, Jesse

2017-12-06

Thermal interface materials (TIMs) are essential for managing heat in modern electronics, and nanocomposite TIMs can offer critical improvements. Here, we demonstrate thermally conductive, mechanically compliant TIMs based on dense, vertically aligned copper nanowires (CuNWs) embedded into polymer matrices. We evaluate the thermal and mechanical characteristics of 20-25% dense CuNW arrays with and without polydimethylsiloxane infiltration. The thermal resistance achieved is below 5 mm 2 K W -1 , over an order of magnitude lower than commercial heat sink compounds. Nanoindentation reveals that the nonlinear deformation mechanics of this TIM are influenced by both the CuNW morphology and the polymer matrix. We also implement a flip-chip bonding protocol to directly attach CuNW composites to copper surfaces, as required in many thermal architectures. Thus, we demonstrate a rational design strategy for nanocomposite TIMs that simultaneously retain the high thermal conductivity of aligned CuNWs and the mechanical compliance of a polymer.

Thermally multiplexed polymerase chain reaction.

Science.gov (United States)

Phaneuf, Christopher R; Pak, Nikita; Saunders, D Curtis; Holst, Gregory L; Birjiniuk, Joav; Nagpal, Nikita; Culpepper, Stephen; Popler, Emily; Shane, Andi L; Jerris, Robert; Forest, Craig R

2015-07-01

Amplification of multiple unique genetic targets using the polymerase chain reaction (PCR) is commonly required in molecular biology laboratories. Such reactions are typically performed either serially or by multiplex PCR. Serial reactions are time consuming, and multiplex PCR, while powerful and widely used, can be prone to amplification bias, PCR drift, and primer-primer interactions. We present a new thermocycling method, termed thermal multiplexing, in which a single heat source is uniformly distributed and selectively modulated for independent temperature control of an array of PCR reactions. Thermal multiplexing allows amplification of multiple targets simultaneously-each reaction segregated and performed at optimal conditions. We demonstrate the method using a microfluidic system consisting of an infrared laser thermocycler, a polymer microchip featuring 1 μl, oil-encapsulated reactions, and closed-loop pulse-width modulation control. Heat transfer modeling is used to characterize thermal performance limitations of the system. We validate the model and perform two reactions simultaneously with widely varying annealing temperatures (48 °C and 68 °C), demonstrating excellent amplification. In addition, to demonstrate microfluidic infrared PCR using clinical specimens, we successfully amplified and detected both influenza A and B from human nasopharyngeal swabs. Thermal multiplexing is scalable and applicable to challenges such as pathogen detection where patients presenting non-specific symptoms need to be efficiently screened across a viral or bacterial panel.

Preparation and Photoluminescence of ZnO Comb-Like Structure and Nanorod Arrays

Science.gov (United States)

Yin, Song; Chen, Yi-qing; Su, Yong; Zhou, Qing-tao

2007-06-01

A large quantity of Zinc oxide (ZnO) comb-like structure and high-density well-aligned ZnO nanorod arrays were prepared on silicon substrate via thermal evaporation process without any catalyst. The morphology, growth mechanism, and optical properties of the both structures were investigated using XRD, SEM, TEM and PL. The resulting comb-teeth, with a diameter about 20 nm, growing along the [0001] direction have a well-defined epitaxial relationship with the comb ribbon. The ZnO nanorod arrays have a diameter about 200 nm and length up to several micrometers growing approximately vertical to the Si substrate. A ZnO film was obtained before the nanorods growth. A growth model is proposed for interpreting the growth mechanism of comb-like zigzag-notch nanostructure. Room temperature photoluminescence measurements under excitation wavelength of 325 nm showed that the ZnO comb-like nanostructure has a weak UV emission at around 384 nm and a strong green emission around 491 nm, which correspond to a near band-edge transition and the singly ionized oxygen vacancy, respectively. In contrast, a strong and sharp UV peak and a weak green peak was obtained from the ZnO nanorod arrays.

A universal approach to electrically connecting nanowire arrays using nanoparticles—application to a novel gas sensor architecture

Science.gov (United States)

Parthangal, Prahalad M.; Cavicchi, Richard E.; Zachariah, Michael R.

2006-08-01

We report on a novel, in situ approach toward connecting and electrically contacting vertically aligned nanowire arrays using conductive nanoparticles. The utility of the approach is demonstrated by development of a gas sensing device employing this nano-architecture. Well-aligned, single-crystalline zinc oxide nanowires were grown through a direct thermal evaporation process at 550 °C on gold catalyst layers. Electrical contact to the top of the nanowire array was established by creating a contiguous nanoparticle film through electrostatic attachment of conductive gold nanoparticles exclusively onto the tips of nanowires. A gas sensing device was constructed using such an arrangement and the nanowire assembly was found to be sensitive to both reducing (methanol) and oxidizing (nitrous oxides) gases. This assembly approach is amenable to any nanowire array for which a top contact electrode is needed.

A universal approach to electrically connecting nanowire arrays using nanoparticles-application to a novel gas sensor architecture

International Nuclear Information System (INIS)

Parthangal, Prahalad M; Cavicchi, Richard E; Zachariah, Michael R

2006-01-01

We report on a novel, in situ approach toward connecting and electrically contacting vertically aligned nanowire arrays using conductive nanoparticles. The utility of the approach is demonstrated by development of a gas sensing device employing this nano-architecture. Well-aligned, single-crystalline zinc oxide nanowires were grown through a direct thermal evaporation process at 550 deg. C on gold catalyst layers. Electrical contact to the top of the nanowire array was established by creating a contiguous nanoparticle film through electrostatic attachment of conductive gold nanoparticles exclusively onto the tips of nanowires. A gas sensing device was constructed using such an arrangement and the nanowire assembly was found to be sensitive to both reducing (methanol) and oxidizing (nitrous oxides) gases. This assembly approach is amenable to any nanowire array for which a top contact electrode is needed

Low concentration ratio solar array for low Earth orbit multi-100 kW application. Volume 1: Design, analysis and development tests

Science.gov (United States)

1983-01-01

A preliminary design effort directed toward a low concentration ratio photovoltaic array system capable of delivering multihundred kilowatts (300 kW to 1000 kW range) in low earth orbit is described. The array system consists of two or more array modules each capable of delivering between 113 kW to 175 kW using silicon solar cells or gallium arsenide solar cells, respectively. The array module deployed area is 1320 square meters and consists of 4356 pyramidal concentrator elements. The module, when stowed in the Space Shuttle's payload bay, has a stowage volume of a cube with 3.24 meters on a side. The concentrator elements are sized for a geometric concentration ratio (GCR) of six with an aperture area of .25 sq. m. The structural analysis and design trades leading to the baseline design are discussed. It describes the configuration, as well as optical, thermal and electrical performance analyses that support the design and overall performance estimates for the array are described.

Phased-array radars

Science.gov (United States)

Brookner, E.

1985-02-01

The operating principles, technology, and applications of phased-array radars are reviewed and illustrated with diagrams and photographs. Consideration is given to the antenna elements, circuitry for time delays, phase shifters, pulse coding and compression, and hybrid radars combining phased arrays with lenses to alter the beam characteristics. The capabilities and typical hardware of phased arrays are shown using the US military systems COBRA DANE and PAVE PAWS as examples.

Double-pass photovoltaic / thermal (PV/T) solar collector with advanced heat transfer features

International Nuclear Information System (INIS)

Mohd Nazari Abu Bakar; Baharudin Yatim; Mohd Yusof Othman; Kamaruzzaman Sopian

2006-01-01

The use of PV/T in combination with concentrating reflectors has a potential to significantly increase power production from a given solar cell area. A prototype double-pass photovoltaic-thermal solar air collector with CPR and fins has been designed and fabricated and its performance over a range of operating conditions was studied. The absorber of the hybrid photovoltaic / thermal (PV/T) collector under investigation consists of an array of solar cells for generating electricity, compound parabolic concentrator (CPR) to increase the radiation intensity falling on the solar cells and fins attached to the back side of the absorber plate to improve heat transfer to the flowing air. The thermal, electrical and combined electrical and thermal efficiencies of the collector are presented and discussed

ISS Solar Array Management

Science.gov (United States)

Williams, James P.; Martin, Keith D.; Thomas, Justin R.; Caro, Samuel

2010-01-01

The International Space Station (ISS) Solar Array Management (SAM) software toolset provides the capabilities necessary to operate a spacecraft with complex solar array constraints. It monitors spacecraft telemetry and provides interpretations of solar array constraint data in an intuitive manner. The toolset provides extensive situational awareness to ensure mission success by analyzing power generation needs, array motion constraints, and structural loading situations. The software suite consists of several components including samCS (constraint set selector), samShadyTimers (array shadowing timers), samWin (visualization GUI), samLock (array motion constraint computation), and samJet (attitude control system configuration selector). It provides high availability and uptime for extended and continuous mission support. It is able to support two-degrees-of-freedom (DOF) array positioning and supports up to ten simultaneous constraints with intuitive 1D and 2D decision support visualizations of constraint data. Display synchronization is enabled across a networked control center and multiple methods for constraint data interpolation are supported. Use of this software toolset increases flight safety, reduces mission support effort, optimizes solar array operation for achieving mission goals, and has run for weeks at a time without issues. The SAM toolset is currently used in ISS real-time mission operations.

Sensor array signal processing

CERN Document Server

Naidu, Prabhakar S

2009-01-01

Chapter One: An Overview of Wavefields 1.1 Types of Wavefields and the Governing Equations 1.2 Wavefield in open space 1.3 Wavefield in bounded space 1.4 Stochastic wavefield 1.5 Multipath propagation 1.6 Propagation through random medium 1.7 ExercisesChapter Two: Sensor Array Systems 2.1 Uniform linear array (ULA) 2.2 Planar array 2.3 Distributed sensor array 2.4 Broadband sensor array 2.5 Source and sensor arrays 2.6 Multi-component sensor array2.7 ExercisesChapter Three: Frequency Wavenumber Processing 3.1 Digital filters in the w-k domain 3.2 Mapping of 1D into 2D filters 3.3 Multichannel Wiener filters 3.4 Wiener filters for ULA and UCA 3.5 Predictive noise cancellation 3.6 Exercises Chapter Four: Source Localization: Frequency Wavenumber Spectrum4.1 Frequency wavenumber spectrum 4.2 Beamformation 4.3 Capon's w-k spectrum 4.4 Maximum entropy w-k spectrum 4.5 Doppler-Azimuth Processing4.6 ExercisesChapter Five: Source Localization: Subspace Methods 5.1 Subspace methods (Narrowband) 5.2 Subspace methods (B...

Large-area, high-intensity PV arrays for systems using dish concentrating optics

Energy Technology Data Exchange (ETDEWEB)

Ward, J.S.; Duda, A.; Zweibel, K.; Coutts, T.J. [National Renewable Energy Lab., Golden, CO (United States)

1998-09-01

In this paper, the authors report on efforts to fabricate monolithic interconnected modules (MIMs) using III-V semiconductors with bandgaps appropriate for the terrestrial solar spectrum. The small size of the component cells comprising the MIM allows for operation at extremely high flux densities and relaxes the requirement for a small spot size to be generated by the optics. This makes possible a PV option for the large dish concentrator systems that have been developed by the solar thermal community for use with Stirling engines. Additionally, the highly effective back-surface reflector integrated into the MIM design is an effective tool for thermal management of the array. Development of this technology would radically alter the projections for PV manufacturing capacity because of the potential for extremely high power generation per unit area of semiconductor material.

Spa therapy in dermatology

Directory of Open Access Journals (Sweden)

Najeeba Riyaz

2011-01-01

Full Text Available Spa therapy constitutes the use of mineral springs and thermal mud to soothe and heal various ailments. Like the mineral springs, seas and oceans are also important centers for spa therapy of which the most important is Dead Sea (DS. DS has been famous for thousands of years for its miraculous curative and cosmetic properties. Intensive research is going on using DS minerals in a wide range of dermatological conditions especially psoriasis, atopic dermatitis, vitiligo and other eczemas and several papers have been published in various international and pharmacological journals.

Vertically aligned carbon nanotube field emitter arrays with Ohmic base contact to silicon by Fe-catalyzed chemical vapor deposition

NARCIS (Netherlands)

Morassutto, M.; Tiggelaar, Roald M.; Smithers, M.A.; Smithers, M.A.; Gardeniers, Johannes G.E.

2016-01-01

Abstract In this study, dense arrays of aligned carbon nanotubes are obtained by thermal catalytic chemical vapor deposition, using Fe catalyst dispersed on a thin Ta layer. Alignment of the carbon nanotubes depends on the original Fe layer thickness from which the catalyst dispersion is obtained by

Passive microfluidic array card and reader

Science.gov (United States)

Dugan, Lawrence Christopher [Modesto, CA; Coleman, Matthew A [Oakland, CA

2011-08-09

A microfluidic array card and reader system for analyzing a sample. The microfluidic array card includes a sample loading section for loading the sample onto the microfluidic array card, a multiplicity of array windows, and a transport section or sections for transporting the sample from the sample loading section to the array windows. The microfluidic array card reader includes a housing, a receiving section for receiving the microfluidic array card, a viewing section, and a light source that directs light to the array window of the microfluidic array card and to the viewing section.

Electromagnetic Formation Flight (EMFF) for Sparse Aperture Arrays

Science.gov (United States)

Kwon, Daniel W.; Miller, David W.; Sedwick, Raymond J.

2004-01-01

Traditional methods of actuating spacecraft in sparse aperture arrays use propellant as a reaction mass. For formation flying systems, propellant becomes a critical consumable which can be quickly exhausted while maintaining relative orientation. Additional problems posed by propellant include optical contamination, plume impingement, thermal emission, and vibration excitation. For these missions where control of relative degrees of freedom is important, we consider using a system of electromagnets, in concert with reaction wheels, to replace the consumables. Electromagnetic Formation Flight sparse apertures, powered by solar energy, are designed differently from traditional propulsion systems, which are based on V. This paper investigates the design of sparse apertures both inside and outside the Earth's gravity field.

Field computation for two-dimensional array transducers with limited diffraction array beams.

Science.gov (United States)

Lu, Jian-Yu; Cheng, Jiqi

2005-10-01

A method is developed for calculating fields produced with a two-dimensional (2D) array transducer. This method decomposes an arbitrary 2D aperture weighting function into a set of limited diffraction array beams. Using the analytical expressions of limited diffraction beams, arbitrary continuous wave (cw) or pulse wave (pw) fields of 2D arrays can be obtained with a simple superposition of these beams. In addition, this method can be simplified and applied to a 1D array transducer of a finite or infinite elevation height. For beams produced with axially symmetric aperture weighting functions, this method can be reduced to the Fourier-Bessel method studied previously where an annular array transducer can be used. The advantage of the method is that it is accurate and computationally efficient, especially in regions that are not far from the surface of the transducer (near field), where it is important for medical imaging. Both computer simulations and a synthetic array experiment are carried out to verify the method. Results (Bessel beam, focused Gaussian beam, X wave and asymmetric array beams) show that the method is accurate as compared to that using the Rayleigh-Sommerfeld diffraction formula and agrees well with the experiment.

Dendrimer-assisted controlled growth of carbon nanotubes for enhanced thermal interface conductance

International Nuclear Information System (INIS)

Amama, Placidus B; Cola, Baratunde A; Sands, Timothy D; Xu, Xianfan; Fisher, Timothy S

2007-01-01

Multi-walled carbon nanotubes (MWCNTs) with systematically varied diameter distributions and defect densities were reproducibly grown from a modified catalyst structure templated in an amine-terminated fourth-generation poly(amidoamine) (PAMAM) dendrimer by microwave plasma-enhanced chemical vapor deposition. Thermal interface resistances of the vertically oriented MWCNT arrays as determined by a photoacoustic technique reveal a strong correlation with the quality as assessed by Raman spectroscopy. This study contributes not only to the development of an active catalyst via a wet chemical route for structure-controlled MWCNT growth, but also to the development of efficient and low-cost MWCNT-based thermal interface materials with thermal interface resistances ≤10 mm 2 K W -1

Thermal-hydraulic modeling of porous bed reactors

International Nuclear Information System (INIS)

Araj, K.J.; Nourbakhsh, H.P.

1987-01-01

Optimum design of nuclear reactor core requires an iterative approach between the thermal-hydraulic, neutronic and operational analysis. This paper concentrates on the thermal-hydraulic behavior of a hydrogen cooled, small particle bed reactor (PBR). The PBR core, modeled here, consists of a hexagonal array of fuel elements embedded in a moderator matrix. The fuel elements are annular packed beds of fuel particles held between two porous cylindrical frits. These particles, 500 to 600 μm in diameter, have a uranium carbide core, which is coated by two layers of graphite and an outer coating of zirconium carbide. Coolant flow, radially inward, from the cold frit through the packed bed and hot frit and axially out the channel, formed by the hot frit, to a common plenum. 5 refs., 1 fig., 2 tabs

Analysis of metastasis of melanoma-bearing hamsters in thermal neutron capture therapy

International Nuclear Information System (INIS)

Ueda, Masataka; Mishima, Yutaka; Ichihashi, Masamitsu

1985-01-01

Melanoma-bearing hamsters were divided into three groups: the MG I was treated with both 10 B 1 -para-boronophenylalanine.HCl ( 10 B 1 -BPA) and neutron capture therapy (NCT); the MG II was treated with NCT alone; and the control group (MG III). The most satisfactory effect on regression was seen in the MG I. When the opposite site to the transplanted tumor site was exposed to thermal neutrons, no enhanced effect on metastasis was seen. Tumor cells of MG I and MG II were transplanted subcutaneously 24 hr after NCT into normal hamsters (MG It and MG IIt), and their growth and metastasis abilities were examined. MG It cells possessed neither growth nor metastasis ability; while MG IIt cells showed normal growth and metastasis abilities. Lethal effects on tumor cells seemed to occur in the MG I at 24 hr after NCT, suggesting no effects of NCT on the metastasis ability of tumor cells. Metastasis was seen in 2 of 8 animals in the MG III; however, inhibitory effects on tumor cells were the same as those in the other groups MG I and MG II. When the cells were exposed to 100 rad and 300 rad of gamma rays to assess effects of gamma rays during NCT, neither tumor growth nor lung metastasis was affected. When the tumor was excised with 5 mm margin, relapse occurred in a high incidence. There was no difference in lung metastasis between NCT and gamma irradiation. (Namekawa, K.)

Chemothermal Therapy for Localized Heating and Ablation of Tumor

Directory of Open Access Journals (Sweden)

Zhong-Shan Deng

2013-01-01

Full Text Available Chemothermal therapy is a new hyperthermia treatment on tumor using heat released from exothermic chemical reaction between the injected reactants and the diseased tissues. With the highly minimally invasive feature and localized heating performance, this method is expected to overcome the ubiquitous shortcomings encountered by many existing hyperthermia approaches in ablating irregular tumor. This review provides a relatively comprehensive review on the latest advancements and state of the art in chemothermal therapy. The basic principles and features of two typical chemothermal ablation strategies (acid-base neutralization-reaction-enabled thermal ablation and alkali-metal-enabled thermal/chemical ablation are illustrated. The prospects and possible challenges facing chemothermal ablation are analyzed. The chemothermal therapy is expected to open many clinical possibilities for precise tumor treatment in a minimally invasive way.

Spontaneous Formation of Nanopillar Arrays in Ultrathin Viscous Films: Critical Role of Thermocapillary Stresses

Science.gov (United States)

Troian, Sandra; Dietzel, Mathias

2010-03-01

Nanoscale structures manifest exceedingly large surface to volume ratios and are therefore highly susceptible to control by surface stresses. Actuation techniques which can exploit this feature provide a key strategy for construction and self-organization of large area arrays. During the past decade, several groups have reported that molten polymer nanofilms subject to an ultra-large transverse thermal gradient undergo spontaneous formation of nanopillar arrays. The prevailing explanation is that coherent interfacial reflection of acoustic phonons causes periodic modulation of the radiation pressure leading to instability and pillar growth. We demonstrate instead that thermocapillary forces play a crucial if not dominant role in the formation process due to the strong modulation of surface tension with temperature. Any nanoscale viscous film is prone to such formations, not just polymeric films. Analysis of the governing interface equation reveals the mechanism controlling the growth, spacing and symmetry of these self-assembling arrays. We discuss how these findings are being used in our laboratory to construct nanoscale components for optical and photonic applications.

Optical properties of ordered vertical arrays of multi-walled carbon nanotubes from FDTD simulations.

Science.gov (United States)

Bao, Hua; Ruan, Xiulin; Fisher, Timothy S

2010-03-15

A finite-difference time-domain (FDTD) method is used to model thermal radiative properties of vertical arrays of multi-walled carbon nanotubes (MWCNT). Individual CNTs are treated as solid circular cylinders with an effective dielectric tensor. Consistent with experiments, the results confirm that CNT arrays are highly absorptive. Compared with the commonly used Maxwell-Garnett theory, the FDTD calculations generally predict larger reflectance and absorbance, and smaller transmittance, which are attributed to the diffraction and scattering within the cylinder array structure. The effects of volume fraction, tube length, tube distance, and incident angle on radiative properties are investigated systematically. Low volume fraction and long tubes are more favorable to achieve low reflectance and high absorbance. For a fixed volume fraction and finite tube length, larger periodicity results in larger reflectance and absorbance. The angular dependence studies reveal an optimum incident angle at which the reflectance can be minimized. The results also suggest that an even darker material could be achieved by using CNTs with good alignment on the top surface.

Josephson junction arrays

International Nuclear Information System (INIS)

Bindslev Hansen, J.; Lindelof, P.E.

1985-01-01

In this review we intend to cover recent work involving arrays of Josephson junctions. The work on such arrays falls naturally into three main areas of interest: 1. Technical applications of Josephson junction arrays for high-frequency devices. 2. Experimental studies of 2-D model systems (Kosterlitz-Thouless phase transition, commensurate-incommensurate transition in frustrated (flux) lattices). 3. Investigations of phenomena associated with non-equilibrium superconductivity in and around Josephson junctions (with high current density). (orig./BUD)

Mass accretion and nested array dynamics from Ni-Clad Ti-Al wire array Z pinches

International Nuclear Information System (INIS)

Jones, Brent Manley; Jennings, Christopher A.; Coverdale, Christine Anne; Cuneo, Michael Edward; Maron, Yitzhak; LePell, Paul David; Deeney, Christopher

2010-01-01

Analysis of 50 mm diameter wire arrays at the Z Accelerator has shown experimentally the accretion of mass in a stagnating z pinch and provided insight into details of the radiating plasma species and plasma conditions. This analysis focused on nested wire arrays with a 2:1 (outeninner) mass, radius, and wire number ratio where Al wires were fielded on the outer array and Ni-clad Ti wires were fielded on the inner array.In this presentation, we will present analysis of data from other mixed Al/Ni-clad Ti configurations to further evaluate nested wire array dynamics and mass accretion. These additional configurations include the opposite configuration to that described above (Ni-clad Ti wires on the outer array, with Al wires on the inner array) as well as higher wire number Al configurations fielded to vary the interaction of the two arrays. These same variations were also assessed for a smaller diameter nested array configuration (40 mm). Variations in the emitted radiation and plasma conditions will be presented, along with a discussion of what the results indicate about the nested array dynamics. Additional evidence for mass accretion will also be presented.

Electrostatic Discharge Test of Multi-Junction Solar Array Coupons After Combined Space Environmental Exposures

Science.gov (United States)

Wright, Kenneth H.; Schneider, Todd; Vaughn, Jason; Hoang, Bao; Funderburk, Victor V.; Wong, Frankie; Gardiner, George

2010-01-01

A set of multi-junction GaAs/Ge solar array test coupons were subjected to a sequence of 5-year increments of combined environmental exposure tests. The test coupons capture an integrated design intended for use in a geosynchronous (GEO) space environment. A key component of this test campaign is conducting electrostatic discharge (ESD) tests in the inverted gradient mode. The protocol of the ESD tests is based on the ISO/CD 11221, the ISO standard for ESD testing on solar array panels. This standard is currently in its final review with expected approval in 2010. The test schematic in the ISO reference has been modified with Space System/Loral designed circuitry to better simulate the on-orbit operational conditions of its solar array design. Part of the modified circuitry is to simulate a solar array panel coverglass flashover discharge. All solar array coupons used in the test campaign consist of 4 cells. The ESD tests are performed at the beginning of life (BOL) and at each 5-year environment exposure point. The environmental exposure sequence consists of UV radiation, electron/proton particle radiation, thermal cycling, and ion thruster plume. This paper discusses the coverglass flashover simulation, ESD test setup, and the importance of the electrical test design in simulating the on-orbit operational conditions. Results from 5th-year testing are compared to the baseline ESD characteristics determined at the BOL condition.

TES arrays for the short wavelength band of the SAFARI instrument on SPICA

Science.gov (United States)

Khosropanah, P.; Hijmering, R.; Ridder, M.; Gao, J. R.; Morozov, D.; Mauskopf, P. D.; Trappe, N.; O'Sullivan, C.; Murphy, A.; Griffin, D.; Goldie, D.; Glowacka, D.; Withington, S.; Jackson, B. D.; Audley, M. D.; de Lange, G.

2012-09-01

SPICA is an infra-red (IR) telescope with a cryogenically cooled mirror (~5K) with three instruments on board, one of which is SAFARI that is an imaging Fourier Transform Spectrometer (FTS) with three bands covering the wavelength of 34-210 μm. We develop transition edge sensors (TES) array for short wavelength band (34-60 μm) of SAFARI. These are based on superconducting Ti/Au bilayer as TES bolometers with a Tc of about 105 mK and thin Ta film as IR absorbers on suspended silicon nitride (SiN) membranes. These membranes are supported by long and narrow SiN legs that act as weak thermal links between the TES and the bath. Previously an electrical noise equivalent power (NEP) of 4×10-19 W/√Hz was achieved for a single pixel of such detectors. As an intermediate step toward a full-size SAFARI array (43×43), we fabricated several 8×9 detector arrays. Here we describe the design and the outcome of the dark and optical tests of several of these devices. We achieved high yield (<93%) and high uniformity in terms of critical temperature (<5%) and normal resistance (7%) across the arrays. The measured dark NEPs are as low as 5×10-19 W/√Hz with a response time of about 1.4 ms at preferred operating bias point. The optical coupling is implemented using pyramidal horns array on the top and hemispherical cavity behind the chip that gives a measured total optical coupling efficiency of 30±7%.

Neutron dosimetry in boron neutron capture therapy

International Nuclear Information System (INIS)

Fairchild, R.G.; Miola, U.J.; Ettinger, K.V.

1981-01-01

The recent development of various borated compounds and the utilization of one of these (Na 2 B 12 H 11 SH) to treat brain tumors in clinical studies in Japan has renewed interest in neutron capture therapy. In these procedures thermal neutrons interact with 10 B in boron containing cells through the 10 B(n,α) 7 Li reaction producing charged particles with a maximum range of approx. 10μm in tissue. Borated analogs of chlorpromazine, porphyrin, thiouracil and deoxyuridine promise improved tumor uptake and blood clearance. The therapy beam from the Medical Research Reactor in Brookhaven contains neutrons from a modified and filtered fission spectrum and dosimetric consequences of the use of the above mentioned compounds in conjunction with thermal and epithermal fluxes are discussed in the paper. One of the important problems of radiation dosimetry in capture therapy is determination of the flux profile and, hence, the dose profile in the brain. This has been achieved by constructing a brain phantom made of TE plastic. The lyoluminescence technique provides a convenient way of monitoring the neutron flux distributions; the detectors for this purpose utilize 6 Li and 10 B compounds. Such compounds have been synthesized specially for the purpose of dosimetry of thermal and epithermal beams. In addition, standard lyoluminescent phosphors, like glutamine, could be used to determine the collisional component of the dose as well as the contribution of the 14 N(n,p) 14 C reaction. Measurements of thermal flux were compared with calculations and with measurements done with activation foils

Carbon nanotube nanoelectrode arrays

Science.gov (United States)

Ren, Zhifeng; Lin, Yuehe; Yantasee, Wassana; Liu, Guodong; Lu, Fang; Tu, Yi

2008-11-18

The present invention relates to microelectode arrays (MEAs), and more particularly to carbon nanotube nanoelectrode arrays (CNT-NEAs) for chemical and biological sensing, and methods of use. A nanoelectrode array includes a carbon nanotube material comprising an array of substantially linear carbon nanotubes each having a proximal end and a distal end, the proximal end of the carbon nanotubes are attached to a catalyst substrate material so as to form the array with a pre-determined site density, wherein the carbon nanotubes are aligned with respect to one another within the array; an electrically insulating layer on the surface of the carbon nanotube material, whereby the distal end of the carbon nanotubes extend beyond the electrically insulating layer; a second adhesive electrically insulating layer on the surface of the electrically insulating layer, whereby the distal end of the carbon nanotubes extend beyond the second adhesive electrically insulating layer; and a metal wire attached to the catalyst substrate material.

Strain and thermal conductivity in ultrathin suspended silicon nanowires

Science.gov (United States)

Fan, Daniel; Sigg, Hans; Spolenak, Ralph; Ekinci, Yasin

2017-09-01

We report on the uniaxial strain and thermal conductivity of well-ordered, suspended silicon nanowire arrays between 10 to 20 nm width and 22 nm half-pitch, fabricated by extreme-ultraviolet (UV) interference lithography. Laser-power-dependent Raman spectroscopy showed that nanowires connected monolithically to the bulk had a consistent strain of ˜0.1 % , whereas nanowires clamped by metal exhibited variability and high strain of up to 2.3%, having implications in strain engineering of nanowires. The thermal conductivity at room temperature was measured to be ˜1 W /m K for smooth nanowires and ˜0.1 W /m K for rougher ones, similar to results by other investigators. We found no modification of the bulk properties in terms of intrinsic scattering, and therefore, the decrease in thermal conductivity is mainly due to boundary scattering. Different types of surface roughness, such as constrictions and line-edge roughness, may play roles in the scattering of phonons of different wavelengths. Such low thermal conductivities would allow for very efficient thermal energy harvesting, approaching and passing values achieved by state-of-the-art thermoelectric materials.

Thermal shock resistance behavior of a functionally graded ceramic: Effects of finite cooling rate

Directory of Open Access Journals (Sweden)

Zhihe Jin

2014-01-01

Full Text Available This work presents a semi-analytical model to explore the effects of cooling rate on the thermal shock resistance behavior of a functionally graded ceramic (FGC plate with a periodic array of edge cracks. The FGC is assumed to be a thermally heterogeneous material with constant elastic modulus and Poisson's ratio. The cooling rate applied at the FGC surface is modeled using a linear ramp function. An integral equation method and a closed form asymptotic temperature solution are employed to compute the thermal stress intensity factor (TSIF. The thermal shock residual strength and critical thermal shock of the FGC plate are obtained using the SIF criterion. Thermal shock simulations for an Al2O3/Si3N4 FGC indicate that a finite cooling rate leads to a significantly higher critical thermal shock than that under the sudden cooling condition. The residual strength, however, is relatively insensitive to the cooling rate.

A front-end electronic system for large arrays of bolometers

Science.gov (United States)

Arnaboldi, C.; Carniti, P.; Cassina, L.; Gotti, C.; Liu, X.; Maino, M.; Pessina, G.; Rosenfeld, C.; Zhu, B. X.

2018-02-01

CUORE is an array of thermal calorimeters composed of 988 crystals held at about 10 mK, whose absorbed energy is read out with semiconductor thermistors. The composition of the crystal is TeO2, and the aim is the study of the double beta decay of 130Te on very long and stable runs. CUPID-0 is an array of 26 Zn82Se crystals with double thermistor readout to study the double beta decay of 82Se. In the present paper, we present an overview of the entire front-end electronic readout chain, from the preamplifier to the anti-aliasing filter. This overview includes motivations, design strategies, circuit implementation and performance results of the electronic system, including other auxiliary yet important elements like power supplies and the slow control communication system. The stringent requirements of stability on the very long experimental runs that are foreseen during CUORE and CUPID-0 operation, are achieved thanks to novel solutions of the front-end preamplifier and of the detector bias circuit setup.

Filter arrays

Science.gov (United States)

Page, Ralph H.; Doty, Patrick F.

2017-08-01

The various technologies presented herein relate to a tiled filter array that can be used in connection with performance of spatial sampling of optical signals. The filter array comprises filter tiles, wherein a first plurality of filter tiles are formed from a first material, the first material being configured such that only photons having wavelengths in a first wavelength band pass therethrough. A second plurality of filter tiles is formed from a second material, the second material being configured such that only photons having wavelengths in a second wavelength band pass therethrough. The first plurality of filter tiles and the second plurality of filter tiles can be interspersed to form the filter array comprising an alternating arrangement of first filter tiles and second filter tiles.

Single-electron tunnel junction array

International Nuclear Information System (INIS)

Likharev, K.K.; Bakhvalov, N.S.; Kazacha, G.S.; Serdyukova, S.I.

1989-01-01

The authors have carried out an analysis of statics and dynamics of uniform one-dimensional arrays of ultrasmall tunnel junctions. The correlated single-electron tunneling in the junctions of the array results in its behavior qualitatively similar to that of the Josephson transmission line. In particular, external electric fields applied to the array edges can inject single-electron-charged solitons into the array interior. Shape of such soliton and character of its interactions with other solitons and the array edges are very similar to those of the Josephson vortices (sine-Gordon solitons) in the Josephson transmission line. Under certain conditions, a coherent motion of the soliton train along the array is possible, resulting in generation of narrowband SET oscillations with frequency f/sub s/ = /e where is the dc current flowing along the array

Direction-of-Arrival Estimation for Coprime Array Using Compressive Sensing Based Array Interpolation

Directory of Open Access Journals (Sweden)

Aihua Liu

2017-01-01

Full Text Available A method of direction-of-arrival (DOA estimation using array interpolation is proposed in this paper to increase the number of resolvable sources and improve the DOA estimation performance for coprime array configuration with holes in its virtual array. The virtual symmetric nonuniform linear array (VSNLA of coprime array signal model is introduced, with the conventional MUSIC with spatial smoothing algorithm (SS-MUSIC applied on the continuous lags in the VSNLA; the degrees of freedom (DoFs for DOA estimation are obviously not fully exploited. To effectively utilize the extent of DoFs offered by the coarray configuration, a compressing sensing based array interpolation algorithm is proposed. The compressing sensing technique is used to obtain the coarse initial DOA estimation, and a modified iterative initial DOA estimation based interpolation algorithm (IMCA-AI is then utilized to obtain the final DOA estimation, which maps the sample covariance matrix of the VSNLA to the covariance matrix of a filled virtual symmetric uniform linear array (VSULA with the same aperture size. The proposed DOA estimation method can efficiently improve the DOA estimation performance. The numerical simulations are provided to demonstrate the effectiveness of the proposed method.

In vitro modifications of the scala tympani environment and the cochlear implant array surface.

Science.gov (United States)

Kontorinis, Georgios; Scheper, Verena; Wissel, Kirsten; Stöver, Timo; Lenarz, Thomas; Paasche, Gerrit

2012-09-01

To investigate the influence of alterations of the scala tympani environment and modifications of the surface of cochlear implant electrode arrays on insertion forces in vitro. Research experimental study. Fibroblasts producing neurotrophic factors were cultivated on the surface of Nucleus 24 Contour Advance electrodes. Forces were recorded by an Instron 5542 Force Measurement System as three modified arrays were inserted into an artificial scala tympani model filled with phosphate-buffered saline (PBS). The recorded forces were compared to control groups including three unmodified electrodes inserted into a model filled with PBS (unmodified environment) or Healon (current practice). Fluorescence microscopy was used before and after the insertions to identify any remaining fibroblasts. Additionally, three Contour Advance electrodes were inserted into an artificial model, filled with alginate/barium chloride solution at different concentrations, while insertion forces were recorded. Modification of the scala tympani environment with 50% to 75% alginate gel resulted in a significant decrease in the insertion forces. The fibroblast-coated arrays also led to decreased forces comparable to those recorded with Healon. Fluorescence microscopy revealed fully cell-covered arrays before and partially covered arrays after the insertion; the fibroblasts on the arrays' modiolar surface remained intact. Modifications of the scala tympani's environment with 50% to 75% alginate/barium chloride and of the cochlear implant electrode surface with neurotrophic factor-producing fibroblasts drastically reduce the insertion forces. As both modifications may serve future intracochlear therapies, it is expected that these might additionally reduce possible insertion trauma. Copyright © 2012 The American Laryngological, Rhinological, and Otological Society, Inc.

The Applicability of Incoherent Array Processing to IMS Seismic Array Stations

Science.gov (United States)

Gibbons, S. J.

2012-04-01

The seismic arrays of the International Monitoring System for the CTBT differ greatly in size and geometry, with apertures ranging from below 1 km to over 60 km. Large and medium aperture arrays with large inter-site spacings complicate the detection and estimation of high frequency phases since signals are often incoherent between sensors. Many such phases, typically from events at regional distances, remain undetected since pipeline algorithms often consider only frequencies low enough to allow coherent array processing. High frequency phases that are detected are frequently attributed qualitatively incorrect backazimuth and slowness estimates and are consequently not associated with the correct event hypotheses. This can lead to missed events both due to a lack of contributing phase detections and by corruption of event hypotheses by spurious detections. Continuous spectral estimation can be used for phase detection and parameter estimation on the largest aperture arrays, with phase arrivals identified as local maxima on beams of transformed spectrograms. The estimation procedure in effect measures group velocity rather than phase velocity and the ability to estimate backazimuth and slowness requires that the spatial extent of the array is large enough to resolve time-delays between envelopes with a period of approximately 4 or 5 seconds. The NOA, AKASG, YKA, WRA, and KURK arrays have apertures in excess of 20 km and spectrogram beamforming on these stations provides high quality slowness estimates for regional phases without additional post-processing. Seven arrays with aperture between 10 and 20 km (MJAR, ESDC, ILAR, KSRS, CMAR, ASAR, and EKA) can provide robust parameter estimates subject to a smoothing of the resulting slowness grids, most effectively achieved by convolving the measured slowness grids with the array response function for a 4 or 5 second period signal. The MJAR array in Japan recorded high SNR Pn signals for both the 2006 and 2009 North Korea

Non-thermal irreversible electroporation (N-TIRE) and adjuvant fractionated radiotherapeutic multimodal therapy for intracranial malignant glioma in a canine patient.

Science.gov (United States)

Garcia, P A; Pancotto, T; Rossmeisl, J H; Henao-Guerrero, N; Gustafson, N R; Daniel, G B; Robertson, J L; Ellis, T L; Davalos, R V

2011-02-01

Non-thermal irreversible electroporation (N-TIRE) has shown promise as an ablative therapy for a variety of soft-tissue neoplasms. Here we describe the therapeutic planning aspects and first clinical application of N-TIRE for the treatment of an inoperable, spontaneous malignant intracranial glioma in a canine patient. The N-TIRE ablation was performed safely, effectively reduced the tumor volume and associated intracranial hypertension, and provided sufficient improvement in neurological function of the patient to safely undergo adjunctive fractionated radiotherapy (RT) according to current standards of care. Complete remission was achieved based on serial magnetic resonance imaging examinations of the brain, although progressive radiation encephalopathy resulted in the death of the dog 149 days after N-TIRE therapy. The length of survival of this patient was comparable to dogs with intracranial tumors treated via standard excisional surgery and adjunctive fractionated external beam RT. Our results illustrate the potential benefits of N-TIRE for in vivo ablation of undesirable brain tissue, especially when traditional methods of cytoreductive surgery are not possible or ideal, and highlight the potential radiosensitizing effects of N-TIRE on the brain.

Light-Emitting Diode-Based Illumination System for In Vitro Photodynamic Therapy

OpenAIRE

Defu Chen; Huifen Zheng; Zhiyong Huang; Huiyun Lin; Zhidong Ke; Shusen Xie; Buhong Li

2012-01-01

The aim of this study is to develop a light-emitting diode- (LED-) based illumination system that can be used as an alternative light source for in vitro photodynamic therapy (PDT). This illumination system includes a red LED array composed of 70 LEDs centered at 643 nm, an air-cooling unit, and a specific-designed case. The irradiance as a function of the irradiation distance between the LED array and the sample, the homogeneity and stability of irradiation, and the effect of long-time irrad...

Percutaneous thermal ablation of renal neoplasms

International Nuclear Information System (INIS)

Tacke, J.; Mahnken, A.H.; Guenther, R.W.

2005-01-01

Due to modern examination techniques such as multidetector computed tomography and high-field magnetic resonance imaging, the detection rate of renal neoplasms is continually increasing. Even though tumors exceeding 4 cm in diameter rarely metastasize, all renal lesions that are possible neoplasms should be treated. Traditional treatment techniques include radical nephrectomy or nephron-sparing resection, which are increasingly performed laparoscopically. Modern thermal ablation techniques such as hyperthermal techniques like radiofrequency ablation RFA, laser induced thermal ablation LITT, focused ultrasound FUS and microwave therapy MW, as well as hypothermal techniques (cryotherapy) may be a useful treatment option for patients who are unfit for or refuse surgical resection. Cryotherapy is the oldest and best known thermal ablation technique and can be performed laparoscopically or percutaneously. Since subzero temperatures have no antistyptic effect, additional maneuvers must be performed to control bleeding. Percutaneous cryotherapy of renal tumors is a new and interesting method, but experience with it is still limited. Radiofrequency ablation is the most frequently used method. Modern probe design allows volumes between 2 and 5 cm in diameter to be ablated. Due to hyperthermal tract ablation, the procedure is deemed to be safe and has a low complication rate. Although there are no randomized comparative studies to open resection, the preliminary results for renal RFA are promising and show RFA to be superior to other thermal ablation techniques. Clinical success rates are over 90% for both, cryo- and radiofrequency ablation. Whereas laser induced thermal therapy is established in hepatic ablation, experience is minimal with respect to renal application. For lesions of more than 2 cm in diameter, additional cooling catheters are required. MR thermometry offers temperature control during ablation. Microwave ablation is characterized by small ablation volumes

Online thermal imaging: a simple approach

Science.gov (United States)

Senior, Mark; Hollock, Steve; Sandhu, Sat; Coy, Joanne; Parkin, Rob

2003-04-01

Continuous monitoring of plant and processes is widely practised but the use of thermal imagers in such systems has always been restricted by camera cost. A radiometric thermal imager can be regarded as equivalent to multiple single point radiometers or a matrix of thermocouples but with the advantages of far denser coverage, non-contact measurement, simpler installation and data processing; in addition several of the advantages of conventional machine vision systems such as shape and position recognition can be provided. IRISYS has developed a multipoint radiometer utilising its low-cost infrared array technology. This unit provides continuous real-time temperature monitoring of 256 data points at an affordable price; it is housed in a small, light-weight, sealed and robust metal case and generates RS232 or Ethernet data output. This paper reviews the radiometer technology and its application to single and multi-camera systems.

Design and thermal performances of a scalable linear Fresnel reflector solar system

International Nuclear Information System (INIS)

Zhu, Yanqing; Shi, Jifu; Li, Yujian; Wang, Leilei; Huang, Qizhang; Xu, Gang

2017-01-01

Highlights: • A scalable linear Fresnel reflector which can supply different temperatures is proposed. • Inclination design of the mechanical structure is used to reduce the end losses. • The maximum thermal efficiency of 64% is achieved in Guangzhou. - Abstract: This paper proposes a scalable linear Fresnel reflector (SLFR) solar system. The optical mirror field which contains an array of linear plat mirrors closed to each other is designed to eliminate the inter-low shading and blocking. Scalable mechanical mirror support which can place different number of mirrors is designed to supply different temperatures. The mechanical structure can be inclined to reduce the end losses. Finally, the thermal efficiency of the SLFR with two stage mirrors is tested. After adjustment, the maximum thermal efficiency of 64% is obtained and the mean thermal efficiency is higher than that before adjustment. The results indicate that the end losses have been reduced effectively by the inclination design and excellent thermal performance can be obtained by the SLFR after adjustment.

Ultrasound therapy applicators for controlled thermal modification of tissue

Science.gov (United States)

Burdette, E. Clif; Lichtenstiger, Carol; Rund, Laurie; Keralapura, Mallika; Gossett, Chad; Stahlhut, Randy; Neubauer, Paul; Komadina, Bruce; Williams, Emery; Alix, Chris; Jensen, Tor; Schook, Lawrence; Diederich, Chris J.

2011-03-01

Heat therapy has long been used for treatments in dermatology and sports medicine. The use of laser, RF, microwave, and more recently, ultrasound treatment, for psoriasis, collagen reformation, and skin tightening has gained considerable interest over the past several years. Numerous studies and commercial devices have demonstrated the efficacy of these methods for treatment of skin disorders. Despite these promising results, current systems remain highly dependent on operator skill, and cannot effectively treat effectively because there is little or no control of the size, shape, and depth of the target zone. These limitations make it extremely difficult to obtain consistent treatment results. The purpose of this study was to determine the feasibility for using acoustic energy for controlled dose delivery sufficient to produce collagen modification for the treatment of skin tissue in the dermal and sub-dermal layers. We designed and evaluated a curvilinear focused ultrasound device for treating skin disorders such as psoriasis, stimulation of wound healing, tightening of skin through shrinkage of existing collagen and stimulation of new collagen formation, and skin cancer. Design parameters were examined using acoustic pattern simulations and thermal modeling. Acute studies were performed in 201 freshly-excised samples of young porcine underbelly skin tissue and 56 in-vivo treatment areas in 60- 80 kg pigs. These were treated with ultrasound (9-11MHz) focused in the deep dermis. Dose distribution was analyzed and gross pathology assessed. Tissue shrinkage was measured based on fiducial markers and video image registration and analyzed using NIH Image-J software. Comparisons were made between RF and focused ultrasound for five energy ranges. In each experimental series, therapeutic dose levels (60degC) were attained at 2-5mm depth. Localized collagen changes ranged from 1-3% for RF versus 8-15% for focused ultrasound. Therapeutic ultrasound applied at high

A thermal technique for local ultrasound intensity measurement: part 2. Application to exposimetry on a medical diagnostic device

International Nuclear Information System (INIS)

Wilkens, V

2010-01-01

Acoustic output measurements on medical ultrasound equipment are usually performed using radiation force balances to determine the output power and using hydrophones to determine pressure and intensity parameters. The local temporal-average ultrasound intensity can be measured alternatively by thermal sensors. The technique was described and prototype sensors were characterized in a preceding paper. Here, the application of such a thermal intensity sensor to the output beam characterization of a typical medical diagnostic device is described. Two transducers, a 7.5 MHz linear array and a 3.5 MHz convex array were investigated in different operating modes. For comparison, hydrophone measurements were also performed. If the spatial averaging effect is taken into account, good agreement is found between both measurement methods. The maximum deviations of the spatial-peak temporal-average intensities I SPTA obtained with the thermal sensor from the corresponding hydrophone-based results were below 12%. The simple thermal technique offers advantages for intensity measurements especially in the case of scanning and combined modes of the diagnostic device, where the synchronization between hydrophone measurements and the complex pulse emission pattern can be difficult

Fiber Laser Array

National Research Council Canada - National Science Library

Simpson, Thomas

2002-01-01

...., field-dependent, loss within the coupled laser array. During this program, Jaycor focused on the construction and use of an experimental apparatus that can be used to investigate the coherent combination of an array of fiber lasers...

Fabrication process for CMUT arrays with polysilicon electrodes, nanometre precision cavity gaps and through-silicon vias