A bag adapted for the handling of a filtering element or filter unit

International Nuclear Information System (INIS)

Marshall, D.A.G.

1980-01-01

The invention relates to a transparent, flexible, synthetic plastics bag adapted to contain a filter element or filter unit so that the latter can be inserted into or removed from a filter casing or duct while being contained in the bag. The bag has a neck portion which is capable of being removably secured in an air-tight manner on to a part of the casing, and gloves or glove portions are provided in, or are formed in, the wall of the bag to permit handles on the filter element or unit to be grasped. (author)

Neutron Transmission of Single-crystal Sapphire Filters

Science.gov (United States)

Adib, M.; Kilany, M.; Habib, N.; Fathallah, M.

2005-05-01

An additive formula is given that permits the calculation of the nuclear capture, thermal diffuse and Bragg scattering cross-sections as a function of sapphire temperature and crystal parameters. We have developed a computer program that allows calculations of the thermal neutron transmission for the sapphire rhombohedral structure and its equivalent trigonal structure. The calculated total cross-section values and effective attenuation coefficient for single-crystalline sapphire at different temperatures are compared with measured values. Overall agreement is indicated between the formula and experimental data. We discuss the use of sapphire single crystal as a thermal neutron filter in terms of the optimum cystal thickness, mosaic spread, temperature, cutting plane and tuning for efficient transmission of thermal-reactor neutrons.

Photonic crystal ring resonator based optical filters for photonic integrated circuits

International Nuclear Information System (INIS)

Robinson, S.

2014-01-01

In this paper, a two Dimensional (2D) Photonic Crystal Ring Resonator (PCRR) based optical Filters namely Add Drop Filter, Bandpass Filter, and Bandstop Filter are designed for Photonic Integrated Circuits (PICs). The normalized output response of the filters is obtained using 2D Finite Difference Time Domain (FDTD) method and the band diagram of periodic and non-periodic structure is attained by Plane Wave Expansion (PWE) method. The size of the device is minimized from a scale of few tens of millimeters to the order of micrometers. The overall size of the filters is around 11.4 μm × 11.4 μm which is highly suitable of photonic integrated circuits

Experience with HEPA filters at United States nuclear installations

International Nuclear Information System (INIS)

Bellamy, R.R.

1977-01-01

Part 50 of Title 10 of the United States Code of Federal Regulations requires that a number of atmosphere cleanup systems be included in the design of commercial nuclear power plants to be licensed in the United States. These filtering systems are to contain high efficiency particulate air (HEPA) filters for removal of radioactive particulate matter generated during normal and accident conditions. Recommendations for the design, testing and maintenance of the filtering systems and HEPA filter components are contained in a number of United States Nuclear Regulatory Commission documents and industry standards. This paper will discuss this published guidance available to designers of filtering systems and the plant operators of U.S. commercial nuclear power plants. The paper will also present a survey of published reports of experience with HEPA filters, failures and possible causes for the failures, and other abnormal occurrences pertaining to HEPA filters installed in U.S. nuclear power installations. A discussion will be included of U.S. practices for qualification of HEPA filters before installation, and verification of continued performance capability at scheduled intervals during operation

Spatial filtering of light by chirped photonic crystals

International Nuclear Information System (INIS)

Staliunas, Kestutis; Sanchez-Morcillo, Victor J.

2009-01-01

We propose an efficient method for spatial filtering of light beams by propagating them through two-dimensional (also three dimensional) chirped photonic crystals, i.e., through the photonic structures with fixed transverse lattice period and with the longitudinal lattice period varying along the direction of the beam propagation. We prove the proposed idea by numerically solving the paraxial propagation equation in refraction-index-modulated media and we evaluate the efficiency of the process by harmonic-expansion analysis. The technique can be also applied for filtering (for cleaning) of the packages of atomic waves (Bose condensates), also to improve the directionality of acoustic and mechanical waves.

The neutron transmission of single crystal MgO filters

International Nuclear Information System (INIS)

Carpenter, J.M.; Hilleke, R.O.

1989-01-01

We have measured and analyzed the wavelength dependence of the transmission probability of a beam of neutrons passing through a single crystal MgO filter at 77 K. The 12.7 cm filter transmits 70% or more of the incident beam at wavelengths greater than about 1.8 A. At shorter wavelengths the transmission probability drops sharply, with 50% transmission occurring at about 1.2 A, and 1% transmission for the range 0.1-0.4 A. We have determined that cooling the filter to 77 K improves the transmission of >1 A neutrons, while further cooling to 25 K shows little additional improvement, and no improvement for short wavelengths. We have identified the wavelengths of the sharp dips in the transmission found in this region caused by Bragg scattering in MgO. We also show how these peaks may be used to calibrate the wavelength scale of time-of-flight measurements taken on instruments using similar filters. (orig.)

Thin film polarizer and color filter based on photo-polymerizable nematic liquid crystal

Science.gov (United States)

Mohammadimasoudi, Mohammad; Neyts, Kristiaan; Beeckman, Jeroen

2015-03-01

We present a method to fabricate a thin film color filter based on a mixture of photo-polymerizable liquid crystal and chiral dopant. A chiral nematic liquid crystal layer reflects light for a certain wavelength interval Δλ (= Δn.P) with the period and Δn the birefringence of the liquid crystal. The reflection band is determined by the chiral dopant concentration. The bandwidth is limited to 80nm and the reflectance is at most 50% for unpolarized incident light. The thin color filter is interesting for innovative applications like polarizer-free reflective displays, polarization-independent devices, stealth technologies, or smart switchable reflective windows to control solar light and heat. The reflected light has strong color saturation without absorption because of the sharp band edges. A thin film polarizer is developed by using a mixture of photo-polymerizable liquid crystal and color-neutral dye. The fabricated thin film absorbs light that is polarized parallel to the c axis of the LC. The obtained polarization ratio is 80% for a film of only 12 μm. The thin film polarizer and the color filter feature excellent film characteristics without domains and can be detached from the substrate which is useful for e.g. flexible substrates.

Cross-section of single-crystal materials used as thermal neutron filters

International Nuclear Information System (INIS)

Adib, M.

2005-01-01

Transmission properties of several single crystal materials important for neutron scattering instrumentation are presented. A computer codes are developed which permit the calculation of thermal diffuse and Bragg-scattering cross-sections of silicon., and sapphire as a function of material's constants, temperature and neutron energy, E, in the range 0.1 MeV .A discussion of the use of their single-crystal as a thermal neutron filter in terms of the optimum crystal thickness, mosaic spread, temperature, cutting plane and tuning for efficient transmission of thermal-reactor neutrons is given

Single-crystal filters for attenuating epithermal neutrons and gamma rays in reactor beams

DEFF Research Database (Denmark)

Rustad, B.M.; Als-Nielsen, Jens Aage; Bahnsen, A.

1965-01-01

Cross section of representative samples of bismuth and quartz were measured at room and liquid nitrogen temperatures over neutron energy range of 0.0007 to 2.0 ev to obtain data for design of single-crystal 32-cm bismuth filters for attenuating fast neutrons and γ-rays in reactor beams; filters may...

Acoustic frequency filter based on anisotropic topological phononic crystals

KAUST Repository

Chen, Zeguo

2017-11-02

We present a design of acoustic frequency filter based on a two-dimensional anisotropic phononic crystal. The anisotropic band structure exhibits either a directional or a combined (global + directional) bandgap at certain frequency regions, depending on the geometry. When the time-reversal symmetry is broken, it may introduce a topologically nontrivial bandgap. The induced nontrivial bandgap and the original directional bandgap result in various interesting wave propagation behaviors, such as frequency filter. We develop a tight-binding model to characterize the effective Hamiltonian of the system, from which the contribution of anisotropy is explicitly shown. Different from the isotropic cases, the Zeeman-type splitting is not linear and the anisotropic bandgap makes it possible to achieve anisotropic propagation characteristics along different directions and at different frequencies.

Acoustic frequency filter based on anisotropic topological phononic crystals

KAUST Repository

Chen, Zeguo; Zhao, Jiajun; Mei, Jun; Wu, Ying

2017-01-01

We present a design of acoustic frequency filter based on a two-dimensional anisotropic phononic crystal. The anisotropic band structure exhibits either a directional or a combined (global + directional) bandgap at certain frequency regions, depending on the geometry. When the time-reversal symmetry is broken, it may introduce a topologically nontrivial bandgap. The induced nontrivial bandgap and the original directional bandgap result in various interesting wave propagation behaviors, such as frequency filter. We develop a tight-binding model to characterize the effective Hamiltonian of the system, from which the contribution of anisotropy is explicitly shown. Different from the isotropic cases, the Zeeman-type splitting is not linear and the anisotropic bandgap makes it possible to achieve anisotropic propagation characteristics along different directions and at different frequencies.

Design of a micromachined terahertz electromagnetic crystals (EMXT) channel-drop filter on silicon-substrate

Science.gov (United States)

Zhou, Kai; Liu, Yong; Si, Liming; Lv, Xin

2013-08-01

An integrated 0.5 THz electromagnetic crystals(EMXT) channel-drop filter based on PBG structure is presented in this paper. A channel-drop filter is a device in which a narrow bandwidth is redirected to another "drop" waveguide while other frequencies are unaffected. It's capable of extracting a certain frequency from a continuous spectrum in the bus channel and passing it to the test channel. It has potential applications in photonic integrated circuits, radio astronomy, THz spectroscopy, THz communication and remote sensing radar receiver. PBG structures(or photonic crystals) are periodic structures which possess band gaps, where the electromagnetic wave of certain ranges of frequencies cannot pass through and is reflected. The proposed channel-drop filter consists of input waveguide,output waveguide and PBG structure. The proposed filter is simulated using the finite element method and can be fabricated by micro-electromechanical systems (MEMS) technology,due to its low cost, high performance and high processing precision.The filter operation principle and fabrication process are discussed.The simulation results show its ability to filter the frequency of 496GHz with a linewidth of approximately 4GHz and transmission of 27.2 dB above background.The loss at resonant frequency is less than 1dB considering the thickness and roughness of gold layer required by the MEMS process.The channel drop efficiency is 84%.

Tunable polarisation-maintaining filter based on liquid crystal photonic bandgap fibre

DEFF Research Database (Denmark)

Scolari, Lara; Olausson, Christina Bjarnal Thulin; Weirich, Johannes

2008-01-01

A tunable and polarisation-maintaining all-in-fibre filter based on a liquid crystal photonic bandgap fibre is demonstrated. Its polarisation extinction ratio reaches 14 dB at 1550 nm wavelength. Its spectral tunability range spans over 250 nm in the temperature range 30–70°C. The measured...

Noise filtering in a multi-channel system using a tunable liquid crystal photonic bandgap fiber

DEFF Research Database (Denmark)

Petersen, Martin Nordal; Scolari, Lara; Tokle, Torger

2008-01-01

This paper reports on the first application of a liquid crystal infiltrated photonic bandgap fiber used as a tunable filter in an optical transmission system. The device allows low-cost amplified spontaneous emission (ASE) noise filtering and gain equalization with low insertion loss and broad...... tunability. System experiments show that the use of this filter increases for times the distance over which the optical signal-to-noise ratio (OSNR) is sufficient for error-free transmission with respect to the case in which no filtering is used....

Iridescence and spectral filtering of the gyroid-type photonic crystals in Parides sesostris wing scales

Science.gov (United States)

Wilts, Bodo D.; Michielsen, Kristel; De Raedt, Hans; Stavenga, Doekele G.

2012-01-01

The cover scales on the wing of the Emerald-patched Cattleheart butterfly, Parides sesostris, contain gyroid-type biological photonic crystals that brightly reflect green light. A pigment, which absorbs maximally at approximately 395 nm, is immersed predominantly throughout the elaborate upper lamina. This pigment acts as a long-pass filter shaping the reflectance spectrum of the underlying photonic crystals. The additional effect of the filtering is that the spatial distribution of the scale reflectance is approximately angle-independent, leading to a stable wing pattern contrast. The spectral tuning of the original reflectance is verified by photonic band structure modelling. PMID:24098853

Feasibility for the medium efficiency filter as a postfilter in the air cleaning unit

International Nuclear Information System (INIS)

Lim, H. S.; Jung, D. Y.; Byun, S. C.; Kim, S. H.

2002-01-01

The Air Cleaning Unit (ACU) is provided in a nuclear facility to filter the radioactive materials in gaseous effluents released from the facility during normal operation and during a postulated accident. The Air Cleaning Unit (ACU) consists of pre-HEPA filters, charcoal adsorber, post HEPA filters, fans, etc. The charcoal filters keep on-site dose and off-site effluents ALARA, consistent with regulatory requirements. The function of HEPA filter downstream of charcoal(carbon) adsorber in ACU is to catch potential radioactive carbon dust and to be a backup in the event of failure of upstream HEPA. Previous Regulatory Guide use only post HEPA filter of charcoal adsorber downstream but the Regulatory Guide of current revisions allows use of 95% dust spot efficiency filters in lieu of HEPA at the downstream of the carbon adsorber. In this paper is described that the background information of filters, Current Regulatory Guide of revised by the United States Nuclear Regulatory Commission and the feasibility for the medium efficiency filter as a carbon adsorber post filter in the Air Cleaning Unit

Unit Root Properties of Seasonal Adjustment and Related Filters: Special Cases

Directory of Open Access Journals (Sweden)

Bell William.R.

2017-03-01

Full Text Available Bell (2012 catalogued unit root factors contained in linear filters used in seasonal adjustment (model-based or from the X-11 method but noted that, for model-based seasonal adjustment, special cases could arise where filters could contain more unit root factors than was indicated by the general results. This article reviews some special cases that occur with canonical ARIMA model based adjustment in which, with some commonly used ARIMA models, the symmetric seasonal filters contain two extra nonseasonal differences (i.e., they include an extra (1 - B(1 - F. This increases by two the degree of polynomials in time that are annihilated by the seasonal filter and reproduced by the seasonal adjustment filter. Other results for canonical ARIMA adjustment that are reported in Bell (2012, including properties of the trend and irregular filters, and properties of the asymmetric and finite filters, are unaltered in these special cases. Special cases for seasonal adjustment with structural ARIMA component models are also briefly discussed.

Realisation and optical engineering of linear variable bandpass filters in nanoporous anodic alumina photonic crystals.

Science.gov (United States)

Sukarno; Law, Cheryl Suwen; Santos, Abel

2017-06-08

We present the first realisation of linear variable bandpass filters in nanoporous anodic alumina (NAA-LVBPFs) photonic crystal structures. NAA gradient-index filters (NAA-GIFs) are produced by sinusoidal pulse anodisation and used as photonic crystal platforms to generate NAA-LVBPFs. The anodisation period of NAA-GIFs is modified from 650 to 850 s to systematically tune the characteristic photonic stopband of these photonic crystals across the UV-visible-NIR spectrum. Then, the nanoporous structure of NAA-GIFs is gradually widened along the surface under controlled conditions by wet chemical etching using a dip coating approach aiming to create NAA-LVBPFs with finely engineered optical properties. We demonstrate that the characteristic photonic stopband and the iridescent interferometric colour displayed by these photonic crystals can be tuned with precision across the surface of NAA-LVBPFs by adjusting the fabrication and etching conditions. Here, we envisage for the first time the combination of the anodisation period and etching conditions as a cost-competitive, facile, and versatile nanofabrication approach that enables the generation of a broad range of unique LVBPFs covering the spectral regions. These photonic crystal structures open new opportunities for multiple applications, including adaptive optics, hyperspectral imaging, fluorescence diagnostics, spectroscopy, and sensing.

Experimental demonstration of a ferroelectric liquid crystal tunable filter for fast demodulation of FBG sensors

Science.gov (United States)

Mathews, Sunish; Semenova, Yuliya; Rajan, Ginu; Farrell, Gerald

2009-05-01

A discretely tunable Surface-Stabilized Ferroelectric Liquid Crystal based Lyot Filter, with tuning speeds in the order of microseconds, is demonstrated experimentally as a channel dropper for the demodulation of multiple Fibre Bragg Grating sensors. The 3-stage Lyot Filter designed and experimentally verified can be used together with the high-speed ratiometric wavelength measurement system employing a fibre bend loss edge filter. Such systems can be used for the demodulation of distributed Fibre Bragg Grating sensors employed in applications such as structural monitoring, industrial sensing and haptic telerobotic surgical systems.

Integrable microwave filter based on a photonic crystal delay line.

Science.gov (United States)

Sancho, Juan; Bourderionnet, Jerome; Lloret, Juan; Combrié, Sylvain; Gasulla, Ivana; Xavier, Stephane; Sales, Salvador; Colman, Pierre; Lehoucq, Gaelle; Dolfi, Daniel; Capmany, José; De Rossi, Alfredo

2012-01-01

The availability of a tunable delay line with a chip-size footprint is a crucial step towards the full implementation of integrated microwave photonic signal processors. Achieving a large and tunable group delay on a millimetre-sized chip is not trivial. Slow light concepts are an appropriate solution, if propagation losses are kept acceptable. Here we use a low-loss 1.5 mm-long photonic crystal waveguide to demonstrate both notch and band-pass microwave filters that can be tuned over the 0-50-GHz spectral band. The waveguide is capable of generating a controllable delay with limited signal attenuation (total insertion loss below 10 dB when the delay is below 70 ps) and degradation. Owing to the very small footprint of the delay line, a fully integrated device is feasible, also featuring more complex and elaborate filter functions.

Electro-optical tunable birefringent filter

Science.gov (United States)

Levinton, Fred M [Princeton, NJ

2012-01-31

An electrically tunable Lyot type filter is a Lyot that include one or more filter elements. Each filter element may have a planar, solid crystal comprised of a material that exhibits birefringence and is electro-optically active. Transparent electrodes may be coated on each face of the crystal. An input linear light polarizer may be located on one side of the crystal and oriented at 45 degrees to the optical axis of the birefringent crystal. An output linear light polarizer may be located on the other side of the crystal and oriented at -45 degrees with respect to the optical axis of the birefringent crystal. When an electric voltage is applied between the electrodes, the retardation of the crystal changes and so does the spectral transmission of the optical filter.

Optical properties of the two-port resonant tunneling filters in two-dimensional photonic crystal slabs

International Nuclear Information System (INIS)

Ren Cheng; Cheng Li-Feng; Kang Feng; Gan Lin; Zhang Dao-Zhong; Li Zhi-Yuan

2012-01-01

We have designed and fabricated two types of two-port resonant tunneling filters with a triangular air-hole lattice in two-dimensional photonic crystal slabs. In order to improve the filtering efficiency, a feedback method is introduced by closing the waveguide. It is found that the relative position between the closed waveguide boundary and the resonator has an important impact on the dropping efficiency. Based on our analyses, two different types of filters are designed. The transmission spectra and scattering-light far-field patterns are measured, which agree well with theoretical prediction. In addition, the resonant filters are highly sensitive to the size of the resonant cavities, which are useful for practical applications

Investigation of 2D photonic crystal structure based channel drop filter using quad shaped photonic crystal ring resonator for CWDM system

Energy Technology Data Exchange (ETDEWEB)

Chhipa, Mayur Kumar, E-mail: mayurchhipa1@gmail.com; Dusad, Lalit Kumar [Government Engineering College Ajmer, Rajasthan (India); Rajasthan Technical University, Kota, Rajasthan (India)

2016-05-06

In this paper, the design & performance of two dimensional (2-D) photonic crystal structure based channel drop filter is investigated using quad shaped photonic crystal ring resonator. In this paper, Photonic Crystal (PhC) based on square lattice periodic arrays of Gallium Indium Phosphide (GaInP) rods in air structure have been investigated using Finite Difference Time Domain (FDTD) method and photonic band gap is being calculated using Plane Wave Expansion (PWE) method. The PhC designs have been optimized for telecommunication wavelength λ= 1571 nm by varying the rods lattice constant. The number of rods in Z and X directions is 21 and 20, with lattice constant 0.540 nm it illustrates that the arrangement of Gallium Indium Phosphide (GaInP) rods in the structure which gives the overall size of the device around 11.4 µm × 10.8 µm. The designed filter gives good dropping efficiency using 3.298, refractive index. The designed structure is useful for CWDM systems. This device may serve as a key component in photonic integrated circuits. The device is ultra compact with the overall size around 123 µm{sup 2}.

A high-transmission liquid-crystal Fabry-Perot infrared filter for electrically tunable spectral imaging detection

Science.gov (United States)

Liu, Zhonglun; Xin, Zhaowei; Long, Huabao; Wei, Dong; Dai, Wanwan; Zhang, Xinyu; Wang, Haiwei; Xie, Changsheng

2018-02-01

Previous studies have presented the usefulness of typical liquid-crystal Fabry-Perot (LC-FP) infrared filters for spectral imaging detection. Yet, their infrared transmission performances still remain to improve or even rise. In this paper, we propose a new type of electrically tunable LC-FP infrared filter to solve the problem above. The key component of the device is a FP resonant cavity composed of two parallel plane mirrors, in which the zinc selenide (ZnSe) materials with a very high transmittance in the mid-long-wavelength infrared regions are used as the electrode substrates and a layer of nano-aluminum (Al) film, which is directly contacted with liquid-crystal materials, is chosen to make high reflective mirrors as well as the electrodes. Particularly, it should be noted that the directional layer made up of ployimide (PI) used previously is removed. The experiment results indicate that the filter can reduce the absorption of infrared wave remarkably, and thus highlight a road to effectively improve the infrared transmittance ability.

Ultra-compact air-mode photonic crystal nanobeam cavity integrated with bandstop filter for refractive index sensing.

Science.gov (United States)

Sun, Fujun; Fu, Zhongyuan; Wang, Chunhong; Ding, Zhaoxiang; Wang, Chao; Tian, Huiping

2017-05-20

We propose and investigate an ultra-compact air-mode photonic crystal nanobeam cavity (PCNC) with an ultra-high quality factor-to-mode volume ratio (Q/V) by quadratically tapering the lattice space of the rectangular holes from the center to both ends while other parameters remain unchanged. By using the three-dimensional finite-difference time-domain method, an optimized geometry yields a Q of 7.2×10 6 and a V∼1.095(λ/n Si ) 3 in simulations, resulting in an ultra-high Q/V ratio of about 6.5×10 6 (λ/n Si ) -3 . When the number of holes on either side is 8, the cavity possesses a high sensitivity of 252 nm/RIU (refractive index unit), a high calculated Q-factor of 1.27×10 5 , and an ultra-small effective V of ∼0.758(λ/n Si ) 3 at the fundamental resonant wavelength of 1521.74 nm. Particularly, the footprint is only about 8×0.7  μm 2 . However, inevitably our proposed PCNC has several higher-order resonant modes in the transmission spectrum, which makes the PCNC difficult to be used for multiplexed sensing. Thus, a well-designed bandstop filter with weak sidelobes and broad bandwidth based on a photonic crystal nanobeam waveguide is created to connect with the PCNC to filter out the high-order modes. Therefore, the integrated structure presented in this work is promising for building ultra-compact lab-on-chip sensor arrays with high density and parallel-multiplexing capability.

Flexible photonic-crystal Fano filters based on transferred semiconductor nanomembranes

Energy Technology Data Exchange (ETDEWEB)

Zhou Weidong; Yang Hongjun; Qiang Zexuan; Chen Li; Yang Weiquan; Chuwongin, Santhad; Zhao Deyin [Department of Electrical Engineering, NanoFAB Center, University of Texas at Arlington, TX 76019 (United States); Ma Zhenqiang; Qin Guoxuan; Pang Huiqing, E-mail: wzhou@uta.ed, E-mail: mazq@engr.wisc.ed [Department of Electrical and Computer Engineering, University of Wisconsin-Madison, WI 53706 (United States)

2009-12-07

Crystalline semiconductor nanomembranes (NMs), which are transferable, stackable, bondable and manufacturable, offer unprecedented opportunities for unique and novel device applications. We report and review here nanophotonic devices based on stacked semiconductor NMs that were built on Si, glass and flexible PET substrates. Photonic-crystal Fano resonance based surface-normal optical filters and broadband reflectors have been demonstrated with unique angle and polarization properties. Such a low temperature NM stacking process can lead to a paradigm shift on silicon photonic integration and inorganic flexible photonics.

Tunable dual-channel filter based on the photonic crystal with air defects.

Science.gov (United States)

Zhao, Xiaodan; Yang, Yibiao; Wen, Jianhua; Chen, Zhihui; Zhang, Mingda; Fei, Hongming; Hao, Yuying

2017-07-01

We propose a tuning filter containing two channels by inserting a defect layer (Air/Si/Air/Si/Air) into a one-dimensional photonic crystal of Si/SiO 2 , which is on the symmetry of the defect. Two transmission peaks (1528.98 and 1564.74 nm) appear in the optical communication S-band and C-band, and the transmittance of these two channels is up to 100%. In addition, this design realizes multi-channel filtering to process large dynamic range or multiple independent signals in the near-infrared band by changing the structure. The tuning range will be enlarged, and the channels can be moved in this range through the easy control of air thickness and incident angle.

Junction-type photonic crystal waveguides for notch- and pass-band filtering

KAUST Repository

Shahid, Naeem

2011-01-01

Evolution of the mode gap and the associated transmission mini stop-band (MSB) as a function of photonic crystal (PhC) waveguide width is theoretically and experimentally investigated. The change of line-defect width is identified to be the most appropriate way since it offers a wide MSB wavelength tuning range. A high transmission narrow-band filter is experimentally demonstrated in a junction-type waveguide composed of two PhC waveguides with slightly different widths. The full width at half maximum is 5.6 nm; the peak transmission is attenuated by only ∼5 dB and is ∼20 dB above the MSBs. Additionally, temperature tuning of the filter were also performed. The results show red-shift of the transmission peak and the MSB edges with a gradient of dλ/dT = 0.1 nm/°C. It is proposed that the transmission MSBs in such junction-type cascaded PhC waveguides can be used to obtain different types of filters. © 2011 Optical Society of America.

Band structures of two dimensional solid/air hierarchical phononic crystals

International Nuclear Information System (INIS)

Xu, Y.L.; Tian, X.G.; Chen, C.Q.

2012-01-01

The hierarchical phononic crystals to be considered show a two-order “hierarchical” feature, which consists of square array arranged macroscopic periodic unit cells with each unit cell itself including four sub-units. Propagation of acoustic wave in such two dimensional solid/air phononic crystals is investigated by the finite element method (FEM) with the Bloch theory. Their band structure, wave filtering property, and the physical mechanism responsible for the broadened band gap are explored. The corresponding ordinary phononic crystal without hierarchical feature is used for comparison. Obtained results show that the solid/air hierarchical phononic crystals possess tunable outstanding band gap features, which are favorable for applications such as sound insulation and vibration attenuation.

Band structures of two dimensional solid/air hierarchical phononic crystals

Energy Technology Data Exchange (ETDEWEB)

Xu, Y.L.; Tian, X.G. [State Key Laboratory for Mechanical Structure Strength and Vibration, Xi' an Jiaotong University, Xi' an 710049 (China); Chen, C.Q., E-mail: chencq@tsinghua.edu.cn [Department of Engineering Mechanics, AML and CNMM, Tsinghua University, Beijing 100084 (China)

2012-06-15

The hierarchical phononic crystals to be considered show a two-order 'hierarchical' feature, which consists of square array arranged macroscopic periodic unit cells with each unit cell itself including four sub-units. Propagation of acoustic wave in such two dimensional solid/air phononic crystals is investigated by the finite element method (FEM) with the Bloch theory. Their band structure, wave filtering property, and the physical mechanism responsible for the broadened band gap are explored. The corresponding ordinary phononic crystal without hierarchical feature is used for comparison. Obtained results show that the solid/air hierarchical phononic crystals possess tunable outstanding band gap features, which are favorable for applications such as sound insulation and vibration attenuation.

Self-collimation-based photonic crystal notch filters

International Nuclear Information System (INIS)

Lee, Sun-Goo; Kim, Seong-Han; Kee, Chul-Sik; Kim, Kap-Joong

2017-01-01

We introduce a design concept of an optical notch filter (NF) utilizing two perfectly reflecting mirrors and a beam splitter. Based on the new design concept, a photonic crystal (PC)-NF based on the self-collimation phenomenon in a two-dimensional PC is proposed and studied through finite-difference time-domain simulations and experimental measurements in a microwave region. The transmission properties of the self-collimation-based PC-NF were demonstrated to be controlled by adjusting the values of parameters such as the radius of rods in the line-defect beam splitter, distance between the two perfectly reflecting mirrors, and radius of rods on the outermost surface of the perfectly reflecting mirrors. Our results indicate that the proposed design concept could provide a new approach to manipulate light propagation, and the PC-NF could increase the applicability of the self-collimation phenomenon in a PC. (paper)

Pressure-controlled terahertz filter based on 1D photonic crystal with a defective semiconductor

Science.gov (United States)

Qinwen, XUE; Xiaohua, WANG; Chenglin, LIU; Youwen, LIU

2018-03-01

The tunable terahertz (THz) filter has been designed and studied, which is composed of 1D photonic crystal (PC) containing a defect layer of semiconductor GaAs. The analytical solution of 1D defective PC (1DDPC) is deduced based on the transfer matrix method, and the electromagnetic plane wave numerical simulation of this 1DDPC is performed by using the finite element method. The calculated and simulated results have confirmed that the filtering transmittance of this 1DDPC in symmetric structure of air/(Si/SiO2) N /GaAs/(SiO2/Si) N /air is far higher than in asymmetric structure of air/(Si/SiO2) N /GaAs/(Si/SiO2) N /air, where the filtering frequency can be tuned by the external pressure. It can provide a feasible route to design the external pressure-controlled THz filter based on 1DPC with a defective semiconductor.

Thermoluminescence dosimeters with narrow bandpass filters

Science.gov (United States)

Walker, Scottie W.

2004-07-20

A dosimetry method exposes more than one thermoluminescence crystals to radiation without using conventional filters, and reads the energy stored in the crystals by converting the energy to light in a conventional manner, and then filters each crystal output in a different portion of the spectrum generated by the crystals.

Characterization of the bistable wideband optical filter on the basis of nonlinear 2D photonic crystal

Energy Technology Data Exchange (ETDEWEB)

Guryev, I. V., E-mail: guryev@ieee.org; Sukhoivanov, I. A., E-mail: guryev@ieee.org; Andrade Lucio, J. A., E-mail: guryev@ieee.org; Manzano, O. Ibarra, E-mail: guryev@ieee.org; Rodriguez, E. Vargaz, E-mail: guryev@ieee.org; Gonzales, D. Claudio, E-mail: guryev@ieee.org; Chavez, R. I. Mata, E-mail: guryev@ieee.org; Gurieva, N. S., E-mail: guryev@ieee.org [University of Guanajuato, Engineering division (Mexico)

2014-05-15

In our work, we investigated the wideband optical filter on the basis of nonlinear photonic crystal. The all-optical flip-flop using ultra-short pulses with duration lower than 200 fs is obtained in such filters. Here we pay special attention to the stability problem of the nonlinear element. To investigate this problem, the temporal response demonstrating the flip-flop have been computed within the certain range of the wavelengths as well as at different input power.

Optimization of phononic filters via genetic algorithms

Energy Technology Data Exchange (ETDEWEB)

Hussein, M I [University of Colorado, Department of Aerospace Engineering Sciences, Boulder, Colorado 80309-0429 (United States); El-Beltagy, M A [Cairo University, Faculty of Computers and Information, 5 Dr. Ahmed Zewail Street, 12613 Giza (Egypt)

2007-12-15

A phononic crystal is commonly characterized by its dispersive frequency spectrum. With appropriate spatial distribution of the constituent material phases, spectral stop bands could be generated. Moreover, it is possible to control the number, the width, and the location of these bands within a frequency range of interest. This study aims at exploring the relationship between unit cell configuration and frequency spectrum characteristics. Focusing on 1D layered phononic crystals, and longitudinal wave propagation in the direction normal to the layering, the unit cell features of interest are the number of layers and the material phase and relative thickness of each layer. An evolutionary search for binary- and ternary-phase cell designs exhibiting a series of stop bands at predetermined frequencies is conducted. A specially formulated representation and set of genetic operators that break the symmetries in the problem are developed for this purpose. An array of optimal designs for a range of ratios in Young's modulus and density are obtained and the corresponding objective values (the degrees to which the resulting bands match the predetermined targets) are examined as a function of these ratios. It is shown that a rather complex filtering objective could be met with a high degree of success. Structures composed of the designed phononic crystals are excellent candidates for use in a wide range of applications including sound and vibration filtering.

Optimization of phononic filters via genetic algorithms

International Nuclear Information System (INIS)

Hussein, M I; El-Beltagy, M A

2007-01-01

A phononic crystal is commonly characterized by its dispersive frequency spectrum. With appropriate spatial distribution of the constituent material phases, spectral stop bands could be generated. Moreover, it is possible to control the number, the width, and the location of these bands within a frequency range of interest. This study aims at exploring the relationship between unit cell configuration and frequency spectrum characteristics. Focusing on 1D layered phononic crystals, and longitudinal wave propagation in the direction normal to the layering, the unit cell features of interest are the number of layers and the material phase and relative thickness of each layer. An evolutionary search for binary- and ternary-phase cell designs exhibiting a series of stop bands at predetermined frequencies is conducted. A specially formulated representation and set of genetic operators that break the symmetries in the problem are developed for this purpose. An array of optimal designs for a range of ratios in Young's modulus and density are obtained and the corresponding objective values (the degrees to which the resulting bands match the predetermined targets) are examined as a function of these ratios. It is shown that a rather complex filtering objective could be met with a high degree of success. Structures composed of the designed phononic crystals are excellent candidates for use in a wide range of applications including sound and vibration filtering

[Decontamination of dental unit waterlines using disinfectants and filters].

Science.gov (United States)

Monarca, S; Garusi, G; Gigola, P; Spampinato, L; Zani, C; Sapelli, P L

2002-10-01

Bacterial contamination of the dental unit water system can become a health problem for patients, particularly if they are immunodepressed. The present study has had the purpose of evaluating the effectiveness of methods of chemical decontamination using different disinfectants (peracetic acid, hydrogen peroxide, silver salts, chloramine T, glutaraldehyde T4) and methods of physical decontamination using synthetic membranes for the filtration of water. A preliminary removal procedure of the biofilm present in the waterline has been followed in a dental unit prepared on purpose for the research; subsequently different 2-week long maintenance procedures were applied using disinfectants injected by a pump and finally the bacterial contamination of the water flowing from the waterline was evaluated. The physical decontamination was performed using 0.22 mm membrane filters, which have been installed also in another dental unit, and the filtered water was analyzed to detect bacterial contamination. The preliminary procedure of biofilm removal succeeded obtaining germ-free water. Among the disinfectants used for the maintenance of the water quality only glutaraldehyde T4 was able to reduce the bacterial contamination under the limit suggested by the ADA. The membrane filter system was not able to purify the water, but when a disinfectant (peracetic acid) was used in the last part of the waterline good results were obtained. At present no decontamination system of dental waterline is available, and glutaraldehyde T4 seems to be the best disinfectant only if integrated with periodic biofilm removal for the maintenance of the water quality.

Silicon on-chip bandpass filters for the multiplexing of high sensitivity photonic crystal microcavity biosensors

International Nuclear Information System (INIS)

Yan, Hai; Zou, Yi; Yang, Chun-Ju; Chakravarty, Swapnajit; Wang, Zheng; Tang, Naimei; Chen, Ray T.; Fan, Donglei

2015-01-01

A method for the dense integration of high sensitivity photonic crystal (PC) waveguide based biosensors is proposed and experimentally demonstrated on a silicon platform. By connecting an additional PC waveguide filter to a PC microcavity sensor in series, a transmission passband is created, containing the resonances of the PC microcavity for sensing purpose. With proper engineering of the passband, multiple high sensitivity PC microcavity sensors can be integrated into microarrays and be interrogated simultaneously between a single input and a single output port. The concept was demonstrated with a 2-channel L55 PC biosensor array containing PC waveguide filters. The experiment showed that the sensors on both channels can be monitored simultaneously from a single output spectrum. Less than 3 dB extra loss for the additional PC waveguide filter is observed

Silicon on-chip bandpass filters for the multiplexing of high sensitivity photonic crystal microcavity biosensors

Energy Technology Data Exchange (ETDEWEB)

Yan, Hai, E-mail: hai.yan@utexas.edu; Zou, Yi; Yang, Chun-Ju [Department of Electrical and Computer Engineering, Microelectronics Research Center, The University of Texas at Austin, 10100 Burnet Rd., Austin, Texas 78758 (United States); Chakravarty, Swapnajit, E-mail: swapnajit.chakravarty@omegaoptics.com [Omega Optics, Inc., 8500 Shoal Creek Blvd., Austin, Texas 78757 (United States); Wang, Zheng [Department of Electrical and Computer Engineering, Microelectronics Research Center, The University of Texas at Austin, 10100 Burnet Rd., Austin, Texas 78758 (United States); Materials Science and Engineering Program, Texas Materials Institute, The University of Texas at Austin, Austin, Texas 78712 (United States); Tang, Naimei; Chen, Ray T., E-mail: raychen@uts.cc.utexas.edu [Department of Electrical and Computer Engineering, Microelectronics Research Center, The University of Texas at Austin, 10100 Burnet Rd., Austin, Texas 78758 (United States); Omega Optics, Inc., 8500 Shoal Creek Blvd., Austin, Texas 78757 (United States); Fan, Donglei [Materials Science and Engineering Program, Texas Materials Institute, The University of Texas at Austin, Austin, Texas 78712 (United States); Department of Mechanical Engineering, The University of Texas at Austin, Austin, Texas 78712 (United States)

2015-03-23

A method for the dense integration of high sensitivity photonic crystal (PC) waveguide based biosensors is proposed and experimentally demonstrated on a silicon platform. By connecting an additional PC waveguide filter to a PC microcavity sensor in series, a transmission passband is created, containing the resonances of the PC microcavity for sensing purpose. With proper engineering of the passband, multiple high sensitivity PC microcavity sensors can be integrated into microarrays and be interrogated simultaneously between a single input and a single output port. The concept was demonstrated with a 2-channel L55 PC biosensor array containing PC waveguide filters. The experiment showed that the sensors on both channels can be monitored simultaneously from a single output spectrum. Less than 3 dB extra loss for the additional PC waveguide filter is observed.

Penggunaan Unit Slow Sand Filter, Ozon Generator dan Rapid Sand Filter Skala Rumah Tangga Untuk Meningkatkan Kualitas Air Sumur Dangkal Menjadi Air Layak Minum (Parameter Zat Organik dan Deterjen

Directory of Open Access Journals (Sweden)

Anindya Prawita Sari

2014-09-01

Full Text Available Air sumur merupakan air tanah yang sering kali digunakan masyarakat untuk aktivitas sehari-hari. Air sumur dengan kadar organik dan deterjen tinggi tidak layak dikonsumsi masyarakat karena dapat menyebabkan berbagai macam penyakit. Selain itu, adanya zat organik dan deterjen mempengaruhi warna dan bau air sumur sehingga tidak layak konsumsi. Slow sand filter merupakan unit pengolahan yang mampu meremoval zat organik pada air. Slow sand filter dan rapid sand filter tidak menggunakan bahan kimia dalam proses pengolahan sehingga lebih ekonomis dan efektif. Sedangkan ozon, efektif digunakan untuk meremoval zat organik yang ada dalam air dengan mengubah rantai zat organik menjadi lebih sederhana. Tujuan penelitian ini adalah untuk mengetahui keefektifan penggunaan slow sand filter, ozon generator dan rapid sand filter dalam menyisihkan beban deterjen dan zat organik pada air sumur. Hasil penelitian menunjukkan bahwa efisiensi removal pada unit slow sand filter untuk beban organik dan deterjen sebesar 57,6% dan 60,5 %, pada unit ozonasi sebesar 47,4% dan 17,5%, dan pada unit rapid sand filter sebesar 50,0% dan 50,9 %.

Improved reproducibility of unit-cell parameters in macromolecular cryocrystallography by limiting dehydration during crystal mounting.

Science.gov (United States)

Farley, Christopher; Burks, Geoffry; Siegert, Thomas; Juers, Douglas H

2014-08-01

In macromolecular cryocrystallography unit-cell parameters can have low reproducibility, limiting the effectiveness of combining data sets from multiple crystals and inhibiting the development of defined repeatable cooling protocols. Here, potential sources of unit-cell variation are investigated and crystal dehydration during loop-mounting is found to be an important factor. The amount of water lost by the unit cell depends on the crystal size, the loop size, the ambient relative humidity and the transfer distance to the cooling medium. To limit water loss during crystal mounting, a threefold strategy has been implemented. Firstly, crystal manipulations are performed in a humid environment similar to the humidity of the crystal-growth or soaking solution. Secondly, the looped crystal is transferred to a vial containing a small amount of the crystal soaking solution. Upon loop transfer, the vial is sealed, which allows transport of the crystal at its equilibrated humidity. Thirdly, the crystal loop is directly mounted from the vial into the cold gas stream. This strategy minimizes the exposure of the crystal to relatively low humidity ambient air, improves the reproducibility of low-temperature unit-cell parameters and offers some new approaches to crystal handling and cryoprotection.

Real-time optical correlator using computer-generated holographic filter on a liquid crystal light valve

Science.gov (United States)

Chao, Tien-Hsin; Yu, Jeffrey

1990-01-01

Limitations associated with the binary phase-only filter often used in optical correlators are presently circumvented in the writing of complex-valued data on a gray-scale spatial light modulator through the use of a computer-generated hologram (CGH) algorithm. The CGH encodes complex-valued data into nonnegative real CGH data in such a way that it may be encoded in any of the available gray-scale spatial light modulators. A CdS liquid-crystal light valve is used for the complex-valued CGH encoding; computer simulations and experimental results are compared, and the use of such a CGH filter as the synapse hologram in a holographic optical neural net is discussed.

Filtering properties of Thue-Morse nano-photonic crystals containing high-temperature superconductor

Science.gov (United States)

Talebzadeh, Robabeh; Bavaghar, Mehrdad

2018-05-01

In this paper, we introduced new design of quasi-periodic layered structures by choosing order two of ternary Thue-Morse structure. We considered Superconductor-dielectric photonic crystal with mirror symmetric as (ABSSAB)N(BASSBA)N composed of two kinds of nano-scale dielectric layers (A and B) and high-temperature superconductor layers where N is the number of period. This structure is assumed to be the free space. By using the transfer matrix method and the two fluid model, we theoretically study the transmission spectrum of ternary Thue-Morse superconducting photonic crystals with mirror symmetry and introduce this structure as a narrow optical filter. We showed that transmission peak so-called defect mode appears itself inside the transmission spectrum of suggested structure as same as defective layered structure. Also, we analyzed the influence of various related parameters such as the operating temperature of superconductor layer on position of defect mode. The redshift of defect mode with increasing the operating temperature was observed.

Tunable ultra-wideband terahertz filter based on three-dimensional arrays of H-shaped plasmonic crystals

International Nuclear Information System (INIS)

Yuan Cai; Xu Shi-Lin; Yao Jian-Quan; Zhao Xiao-Lei; Cao Xiao-Long; Wu Liang

2014-01-01

A face-to-face system of double-layer three-dimensional arrays of H-shaped plasmonic crystals is proposed, and its transmission and filtering properties are investigated in the terahertz regime. Simulation results show that our design has excellent filtering properties. It has an ultra-wide bandgap and passband with steep band-edges, and the transmittance of the passband and the forbidden band are very close to 1 and 0, respectively. As the distance between the two face-to-face plates increases, the resonance frequency exhibits a gradual blueshift from 0.88 THz to 1.30 THz. Therefore, we can dynamically control the bandwidths of bandgap and passband by adding a piezoelectric ceramic plate between the two crystal plates. Furthermore, the dispersion relations of modes and electric field distributions are presented to analyze the generation mechanisms of bandgaps and to explain the location of bandgaps and the frequency shift phenomenon. Due to the fact that our design can provide many resonant modes, the bandwidth of the bandgaps can be greatly broadened. This paper can serve as a valuable reference for the design of terahertz functional devices and three-dimensional terahertz metamaterials. (interdisciplinary physics and related areas of science and technology)

Polarization filtering in the visible wavelength range using surface plasmon resonance and a sunflower-type photonic quasi-crystal fiber

Science.gov (United States)

Yan, Bei; Wang, Anran; Liu, Exian; Tan, Wei; Xie, Jianlan; Ge, Rui; Liu, Jianjun

2018-04-01

A novel polarization filter based on a sunflower-type photonic quasi-crystal fiber (PQF) is proposed in this paper. We also discuss different methods to tune the filter wavelength. The proposed filter can efficiently produce polarized light with visible wavelengths by using the resonance between the second-order surface plasmon polariton mode and the core mode of the PQF. The filtered wavelength can be tuned between 0.55 µm and 0.68 µm by adjusting the thickness of the gold film. When the thickness of the gold film is 25.3 nm, the resonance loss in the y-polarized direction reaches 11707 dB m‑1 for a wavelength of 0.6326 µm, and the full width at half maximum is only 5 nm. Due to the flexible design and absence of both polarization coupling and polarization dispersion, this polarization filter can be used in devices that require narrow-band filtering.

Design of an optomechanical filter based on solid/solid phoxonic crystals

Science.gov (United States)

Moradi, Pedram; Bahrami, Ali

2018-03-01

We simulate a phoxonic crystal which shows complete phononic and TM-polarized photonic bandgaps. The constituent materials are tungsten and polymethyl methacrylate, and we obtained these bandgaps with a filling factor of only 28%, which is very compatible with the fabrication method. A cavity was then defined that selects narrow passbands of optical and elastic waves. In order to maximize the quality factor, a defect rod is added in the output waveguide. The final structure filters an optical wavelength of 840 nm (with corresponding frequency of 357 THz) and an elastic frequency of 3.6703 GHz. Simulations are done by using finite element, plane wave expansion, and finite difference time domain methods.

Changing ventilation filters

International Nuclear Information System (INIS)

Hackney, S.

1980-01-01

A filter changing unit has a door which interlocks with the door of a filter chamber so as to prevent contamination of the outer surfaces of the doors by radioactive material collected on the filter element and a movable support which enables a filter chamber thereonto to be stored within the unit in such a way that the doors of the unit and the filter chamber can be replaced. The door pivots and interlocks with another door by means of a bolt, a seal around the periphery lip of the first door engages the periphery of the second door to seal the gap. A support pivots into a lower filter element storage position. Inspection windows and glove ports are provided. The unit is releasably connected to the filter chamber by bolts engaging in a flange provided around an opening. (author)

Tunable all-optical photonic crystal channel drop filter for DWDM systems

Science.gov (United States)

Habibiyan, H.; Ghafoori-Fard, H.; Rostami, A.

2009-06-01

In this paper we propose a tunable channel drop filter in a two-dimensional photonic crystal, based on coupled-cavity waveguides with alternating small and large defects and an electromagnetically induced transparency phenomenon. By utilizing this phenomenon a narrower linewidth is obtained and also the frequency of the dropped signal becomes tunable. Simulation results show that the proposed filter is suitable for dense wavelength-division multiplexing (DWDM) systems with 0.8 nm channel spacing. Using this novel component, two ultrasmall eight-channel double-sided and single-sided demultiplexers are introduced. The properties of these devices are investigated using the finite-difference time-domain method. For the single-sided device, transmission loss is 1.5 ± 0.5 dB, the cross-talk level between adjacent channels is better than -18 dB and the average 3 dB optical passband is 0.36 nm. Using planar silicon-on-insulator technology, the physical area for the single-sided component is 700 µm2 and for the double-sided component is 575 µm2. To the best of our knowledge, these are the smallest all-optical demultiplexers with this spectral resolution reported to date. Malfunction of the proposed device due to fabrication errors is modeled and its tunable characteristic is demonstrated.

Cross-correlated imaging of single-mode photonic crystal rod fiber with distributed mode filtering

DEFF Research Database (Denmark)

Laurila, Marko; Barankov, Roman; Jørgensen, Mette Marie

2013-01-01

Photonic crystal bandgap fibers employing distributed mode filtering design provide near diffraction-limited light outputs, a critical property of fiber-based high-power lasers. Microstructure of the fibers is tailored to achieve single-mode operation at specific wavelength by resonant mode...... identify regimes of resonant coupling between higher-order core modes and cladding band. We demonstrate a passive fiber design in which the higher-order modal content inside the single-mode guiding regime is suppressed by at least 20 dB even for significantly misaligned input-coupling configurations....

Inulin isoforms differ by repeated additions of one crystal unit cell

Science.gov (United States)

Cooper, Peter D.; Barclay, Thomas G.; Ginic-Markovic, Milena; Gerson, Andrea R.; Petrovsky, Nikolai

2014-01-01

Inulin isoforms, especially delta inulin, are important biologically as immune activators and clinically as vaccine adjuvants. In exploring action mechanisms, we previously found regular increments in thermal properties of the seven-member inulin isoform series that suggested regular additions of some energetic structural unit. Because the previous isolates carried additional longer chains that masked defining ranges, these were contrasted with new isoform isolates comprising only inulin chain lengths defining that isoform. The new series began with 19 fructose units per chain (alpha-1 inulin), increasing regularly by 6 fructose units per isoform. Thus the ‘energetic unit’ equates to 6 fructose residues per chain. All isoforms showed indistinguishable X-ray diffraction patterns that were also identical with known inulin crystals. We conclude that an ‘energetic unit’ equates to one helix turn of 6 fructose units per chain as found in one unit cell of the inulin crystal. Each isoform chain comprised progressively more helix turns plus one additional fructose and glucose residues per chain. PMID:24528745

Broad bandwidth and 600 μm length photonic crystal fiber polarization filter at the communication window of 1.55 μm

Science.gov (United States)

Zhang, Zhen; Li, Shuguang; Liu, Qiang; Zhang, Shuhuan; Wang, Yujun; Wu, Junjun

2018-02-01

A broad bandwidth and 600-μm length photonic crystal fiber polarization filter at the communication window of 1.55 μm is proposed. The physical parameters are analyzed by the finite element method. In the structure, the loss is 705.81 dB/cm for y-polarized mode and 24.06 dB/cm for x-polarized mode at the wavelength of 1.55 μm; the y-polarized mode will be filtered out because of this property. The bandwidth of an extinction ratio (ER) better than -20 dB is 65 nm when the filter length is 600 μm, and the ER is -41 dB at the communication wavelength of 1.55 μm. The filter structure is simple and easy to produce, and it can be used to produce a single-polarization filter.

Design of Double PG Crystal Neutron Diffractometer

International Nuclear Information System (INIS)

Adib, M.; Habib, N.; El-Mesiry, M.S.; Fathallah, M.

2011-01-01

The design of a diffractometer containing two pyrolytic graphite (PG) crystals to select monochromatic neutrons in the range of wavelengths longer than 0.26 nm is given. The first crystal is high oriented pyrolytic graphite (HOPG) set at glancing angle to reflect monochromatic neutrons with a selected wavelength. The second is a low quality PG crystal filter, set at take-off-angle such that, it transmits the selected monochromatic neutrons and rejects the higher order contaminations accompanying the first order reflection. It was shown that, 2 mm thick of PG crystal having 0.30 FWHM on mosaic spread are the optimum parameters of monochromator PG crystal. While the optimum thickness and mosaic spread of the PG crystal filter were selected to have low contamination factor of higher order reflections. The optimum parameters of the PG filter crystal were calculated using the computer package Graphite recently developed in our laboratory. Calculation shows that, 3 cm thick PG filter (20 on mosaic spread) is sufficient to almost eliminate the higher order contaminations accompanying the main monochromatic neutrons with

The history of ceramic filters.

Science.gov (United States)

Fujishima, S

2000-01-01

The history of ceramic filters is surveyed. Included is the history of piezoelectric ceramics. Ceramic filters were developed using technology similar to that of quartz crystal and electro-mechanical filters. However, the key to this development involved the theoretical analysis of vibration modes and material improvements of piezoelectric ceramics. The primary application of ceramic filters has been for consumer-market use. Accordingly, a major emphasis has involved mass production technology, leading to low-priced devices. A typical ceramic filter includes monolithic resonators and capacitors packaged in unique configurations.

Tunable electro-optic filter stack

Science.gov (United States)

Fontecchio, Adam K.; Shriyan, Sameet K.; Bellingham, Alyssa

2017-09-05

A holographic polymer dispersed liquid crystal (HPDLC) tunable filter exhibits switching times of no more than 20 microseconds. The HPDLC tunable filter can be utilized in a variety of applications. An HPDLC tunable filter stack can be utilized in a hyperspectral imaging system capable of spectrally multiplexing hyperspectral imaging data acquired while the hyperspectral imaging system is airborne. HPDLC tunable filter stacks can be utilized in high speed switchable optical shielding systems, for example as a coating for a visor or an aircraft canopy. These HPDLC tunable filter stacks can be fabricated using a spin coating apparatus and associated fabrication methods.

Quasi-periodic photonic crystal Fabry–Perot optical filter based on Si/SiO2 for visible-laser spectral selectivity

Science.gov (United States)

Qi, Dong; Wang, Xian; Cheng, Yongzhi; Chen, Fu; Liu, Lei; Gong, Rongzhou

2018-06-01

We report on a 1D quasi-periodic photonic crystal Fabry–Perot optical filter Cs(Si/SiO2)3(SiO2/Si)3 for spectral selectivity of visible light and 1.55 µm laser. A material transparency interval of 1.03–2.06 µm makes Si a unique choice of high refractive index material. Owing to the CIE 1931 standard and equal inclination interference, the designed structure can be successfully fabricated with a certain color (brown, khaki, or blue) corresponding to the different Cs physical thickness d and response R(λ). In addition, the peak transmittance T max of the proposed structure can reach as high as 92.56% (Cs  =  20 nm), 90.83% (Cs  =  40 nm), and 88.85% (Cs  =  60 nm) with a relatively narrow full width at half maximum of 4.4, 4.6, and 4.8 nm at 1.55 µm. The as-prepared structure indicates that it is feasible for a photonic crystal Fabry–Perot optical filter to achieve visible-laser (1.55 µm) spectral selectivity.

Exposure to space radiation of high-performance infrared multilayer filters

Science.gov (United States)

Seeley, J. S.; Hawkins, G. J.; Hunneman, R.

1991-01-01

The University of Reading experiment exposed IR interference filters and crystal substrates on identical earth facing and leading-edge sites of the Long Duration Exposure Facility (LDEF). Filters mostly comprised multilayer coatings of lead telluride (PbTe)/II-IV on germanium (Ge) and other substrates: crystals comprised CdTe, MgF2, sapphire, quartz, silicon, and some softer materials. Identical control samples were maintained in the laboratory throughout the experiment. The filters were novel in their design, construction and manufacture, and categorized high-performance because of their ability to resolve emission spectra of the important atmospheric gases for various purposes in remote sensing. No significant changes were found in the spectra of the hard-coated filters or in the harder crystals (the softer materials were degraded to an extent). By virtue of this well-documented and long exposure in LDEF, the qualification of the filter type is significantly improved for its future requirements.

Protein crystal growth results from the United States Microgravity Laboratory-1 mission

Science.gov (United States)

Delucas, Lawrence J.; Moore, K. M.; Vanderwoerd, M.; Bray, T. L.; Smith, C.; Carson, M.; Narayana, S. V. L.; Rosenblum, W. M.; Carter, D.; Clark, A. D, Jr.

1994-01-01

Protein crystal growth experiments have been performed by this laboratory on 18 Space Shuttle missions since April, 1985. In addition, a number of microgravity experiments also have been performed and reported by other investigators. These Space Shuttle missions have been used to grow crystals of a variety of proteins using vapor diffusion, liquid diffusion, and temperature-induced crystallization techniques. The United States Microgravity Laboratory - 1 mission (USML-1, June 25 - July 9, 1992) was a Spacelab mission dedicated to experiments involved in materials processing. New protein crystal growth hardware was developed to allow in orbit examination of initial crystal growth results, the knowledge from which was used on subsequent days to prepare new crystal growth experiments. In addition, new seeding hardware and techniques were tested as well as techniques that would prepare crystals for analysis by x-ray diffraction, a capability projected for the planned Space Station. Hardware that was specifically developed for the USML-1 mission will be discussed along with the experimental results from this mission.

Real-time mass measurement of dust particles deposited on vessel wall in a divertor simulator using quartz crystal microbalances

International Nuclear Information System (INIS)

Tateishi, Mizuki; Koga, Kazunori; Katayama, Ryu; Yamashita, Daisuke; Kamataki, Kunihiro; Seo, Hyunwoong; Itagaki, Naho; Shiratani, Masaharu; Ashikawa, Naoko; Masuzaki, Suguru; Nishimura, Kiyohiko; Sagara, Akio

2015-01-01

We are developing a dust monitoring method using quartz crystal microbalances (QCMs) equipped with a dust eliminating filter. Here we report a dust eliminating ratio of the filter and first measurement results of the QCMs in a divertor simulator. The volume of spherical dust in unit area on the filter and QCM under the filter were 2.09 × 10 −9 and 1.22 × 10 −10 m 3 m −2 , respectively. Thus, the dust eliminating ratio of the filter is 94.2%. The QCM without the filter gives deposition rate due to radicals and dust particles, whereas the QCM with the filter gives deposition rate predominantly due to radicals. From the results, we deduce information of mass fraction of dust particles in deposits

Neutron Beam Filters

International Nuclear Information System (INIS)

Adib, M.

2011-01-01

The purpose of filters is to transmit neutrons with selected energy, while remove unwanted ones from the incident neutron beam. This reduces the background, and the number of spurious. The types of commonly used now-a-day neutron filters and their properties are discussed in the present work. There are three major types of neutron filters. The first type is filter of selective thermal neutron. It transmits the main reflected neutrons from a crystal monochromate, while reject the higher order contaminations accompanying the main one. Beams coming from the moderator always contain unwanted radiation like fast neutrons and gamma-rays which contribute to experimental background and to the biological hazard potential. Such filter type is called filter of whole thermal neutron spectrum. The third filter type is it transmits neutrons with energies in the resonance energy range (En . 1 KeV). The main idea of such neutron filter technique is the use of large quantities of a certain material which have the deep interference minima in its total neutron cross-section. By transmitting reactor neutrons through bulk layer of such material, one can obtain the quasimonochromatic neutron lines instead of white reactor spectrum.

Side loading filter apparatus

International Nuclear Information System (INIS)

Reynolds, K.E.

1981-01-01

A side loading filter chamber for use with radioactive gases is described. The equipment incorporates an inexpensive, manually operated, mechanism for aligning filter units with a number of laterally spaced wall openings and for removing the units from the chamber. (U.K.)

Bragg reflection transmission filters for variable resolution monochromators

International Nuclear Information System (INIS)

Chapman, D.

1989-01-01

There are various methods for improving the angular and spectral resolution of monochromator and analyzer systems. The novel system described here, though limited to higher x-ray energies (>20keV), is based on a dynamical effect occurring on the transmitted beam with a thin perfect crystal plate set in the Bragg reflection case. In the case of Bragg reflection from a perfect crystal, the incident beam is rapidly attenuated as it penetrates the crystal in the range of reflection. This extinction length is of the order of microns. The attenuation length, which determines the amount of normal transmission through the plate is generally much longer. Thus, in the range of the Bragg reflection the attenuation of the transmitted beam can change by several orders of magnitude with a small change in energy or angle. This thin crystal plate cuts a notch in the transmitted beam with a width equal to its Darwin width, thus acting as a transmission filter. When used in a non-dispersive mode with other monochromator crystals, the filter when set at the Bragg angle will reflect the entire Darwin width of the incident beam and transmit the wings of the incident beam distribution. When the element is offset in angle by some fraction of the Darwin width, the filter becomes useful in adjusting the angular width of the transmitted beam and removing a wing. Used in pairs with a symmetric offset, the filters can be used to continuously adjust the intrinsic angular divergence of the beam with good wing reduction. Instances where such filters may be useful are in improving the angular resolution of a small angle scattering camera. These filters may be added to a Bonse-Hart camera with one pair on the incident beam to reduce the intrinsic beam divergence and a second pair on the analyzer arm to improve the analyzer resolution. 2 refs., 3 Figs

The Fate of Mengovirus on Fiberglass Filter of Air Handling Units.

Science.gov (United States)

Bandaly, Victor; Joubert, Aurélie; Le Cann, Pierre; Andres, Yves

2017-12-01

One of the most important topics that occupy public health problems is the air quality. That is the reason why mechanical ventilation and air handling units (AHU) were imposed by the different governments in the collective or individual buildings. Many buildings create an artificial climate using heating, ventilation, and air-conditioning systems. Among the existing aerosols in the indoor air, we can distinguish the bioaerosol with biological nature such as bacteria, viruses, and fungi. Respiratory viral infections are a major public health issue because they are usually highly infective. We spend about 90% of our time in closed environments such as homes, workplaces, or transport. Some studies have shown that AHU contribute to the spread and transport of viral particles within buildings. The aim of this work is to study the characterization of viral bioaerosols in indoor environments and to understand the fate of mengovirus eukaryote RNA virus on glass fiber filter F7 used in AHU. In this study, a set-up close to reality of AHU system was used. The mengovirus aerosolized was characterized and measured with the electrical low pressure impact and the scanner mobility particle size and detected with RT-qPCR. The results about quantification and the level of infectivity of mengovirus on the filter and in the biosampler showed that mengovirus can pass through the filter and remain infectious upstream and downstream the system. Regarding the virus infectivity on the filter under a constant air flow, mengovirus was remained infectious during 10 h after aerosolization.

Transmission properties of one-dimensional ternary plasma photonic crystals

International Nuclear Information System (INIS)

Shiveshwari, Laxmi; Awasthi, S. K.

2015-01-01

Omnidirectional photonic band gaps (PBGs) are found in one-dimensional ternary plasma photonic crystals (PPC) composed of single negative metamaterials. The band characteristics and transmission properties are investigated through the transfer matrix method. We show that the proposed structure can trap light in three-dimensional space due to the elimination of Brewster's angle transmission resonance allowing the existence of complete PBG. The results are discussed in terms of incident angle, layer thickness, dielectric constant of the dielectric material, and number of unit cells (N) for TE and TM polarizations. It is seen that PBG characteristics is apparent even in an N ≥ 2 system, which is weakly sensitive to the incident angle and completely insensitive to the polarization. Finite PPC could be used for multichannel transmission filter without introducing any defect in the geometry. We show that the locations of the multichannel transmission peaks are in the allowed band of the infinite structure. The structure can work as a single or multichannel filter by varying the number of unit cells. Binary PPC can also work as a polarization sensitive tunable filter

Transmission properties of one-dimensional ternary plasma photonic crystals

Energy Technology Data Exchange (ETDEWEB)

Shiveshwari, Laxmi [Department of Physics, K. B. Womens' s College, Hazaribagh 825 301 (India); Awasthi, S. K. [Department of Physics and Material Science and Engineering, Jaypee Institute of Information Technology, Noida 201 304 (India)

2015-09-15

Omnidirectional photonic band gaps (PBGs) are found in one-dimensional ternary plasma photonic crystals (PPC) composed of single negative metamaterials. The band characteristics and transmission properties are investigated through the transfer matrix method. We show that the proposed structure can trap light in three-dimensional space due to the elimination of Brewster's angle transmission resonance allowing the existence of complete PBG. The results are discussed in terms of incident angle, layer thickness, dielectric constant of the dielectric material, and number of unit cells (N) for TE and TM polarizations. It is seen that PBG characteristics is apparent even in an N ≥ 2 system, which is weakly sensitive to the incident angle and completely insensitive to the polarization. Finite PPC could be used for multichannel transmission filter without introducing any defect in the geometry. We show that the locations of the multichannel transmission peaks are in the allowed band of the infinite structure. The structure can work as a single or multichannel filter by varying the number of unit cells. Binary PPC can also work as a polarization sensitive tunable filter.

Multiple order reflections in crystal neutron monochromators

International Nuclear Information System (INIS)

Fulfaro, R.

1976-01-01

A study of the higher order reflections in neutron crystal monochromators was made in order to obtain, for the IEA single crystal spectrometer, the operation range of 1,0eV to 0,01eV. Two crystals were studied, an Al(III) near 1,0eV and a Ge(III) in lower energies. For the Ge(III) case the higher order contaminations in the reflected beam were determined using as standard the gold total neutron cross section and performing the crystal reflectivity calculation for several orders of reflection. The knowledge of the contamination for each order as a function of neutron wavelength allows the optimization of the filter thickness in order to avoid higher order neutrons. The Ge(III) crystal was used because its second order reflections are theoretically forbidden, giving an advantage on other crystals, since measurements can be made until 0.02eV directly without filters. In the energy range 0.02 to 0.01eV, order contaminations higher than the second are present, therefore, either quartz filters are employed or calculated corrections are applied to the experimental data. The Al(III) crystal was used in order to estimate the second order contamination effect, in the iridium resonance measurements, at E 0 = 0.654eV. In that region, approximations can be made and it was not necessary to make the crystal reflectivity calculation for the filters thickness optimization. Since only the second order affects the results in that region, tellurium was used for the filtration, because this element has a resonance in the range of neutrons with energy 4E [pt

Pyrolytic Graphite as a Selective Neutron Filter

International Nuclear Information System (INIS)

Adib, M.; Habib, N.; Fathalla, M.

2006-01-01

The transmission of neutrons through pyrolytic graphite (PG) crystals, set at different angles with respect to incident beam, were calculated using an additive formula. A computer program HOPG was developed to provide the required calculation. An overall agreement between the calculated neutron transmissions through a slab of 1,85 mm thick PG crystal with an angular spread of c-axes of 0,4 degree, set at different angles to the incident beam, and the available experimental ones in the wavelength range from (0,02 to 1,4) nm were obtained. A feasibility study for use of PG crystal as an efficient second-order neutron filter is detailed in terms of crystal thickness, angular spread of c-axes and its operation with respect to the neutron beam. It was shown that a PG crystal with an angular spread of c-axes and its orientation with respect to the neutron beam. It was shown that a PG crystal with an angular spread of 0,8 degree is sufficient for optimum scattering of second-order neutrons in the wavelength band (0,384-0,183) nm, by adjusting the filter in an appropriate orientation

Gaussian Filtering with Tapered Oil-Filled Photonic Bandgap Fibers

DEFF Research Database (Denmark)

Brunetti, Anna Chiara; Scolari, Lara; Weirich, Johannes

2008-01-01

A tunable Gaussian filter based on a tapered oil-filled photonic crystal fiber is demonstrated. The filter is centered at X=1364nm with a bandwidth (FWHM) of 237nm. Tunability is achieved by changing the temperature of the filter. A shift of 210nm of the central wavelength has been observed...

Polarization-Insensitive Tunable Optical Filters based on Liquid Crystal Polarization Gratings

Science.gov (United States)

Nicolescu, Elena

Tunable optical filters are widely used for a variety of applications including spectroscopy, optical communication networks, remote sensing, and biomedical imaging and diagnostics. All of these application areas can greatly benefit from improvements in the key characteristics of the tunable optical filters embedded in them. Some of these key parameters include peak transmittance, bandwidth, tuning range, and transition width. In recent years research efforts have also focused on miniaturizing tunable optical filters into physically small packages for compact portable spectroscopy and hyperspectral imaging applications such as real-time medical diagnostics and defense applications. However, it is important that miniaturization not have a detrimental effect on filter performance. The overarching theme of this dissertation is to explore novel configurations of Polarization Gratings (PGs) as simple, low-cost, polarization-insensitive alternatives to conventional optical filtering technologies for applications including hyperspectral imaging and telecommunications. We approach this goal from several directions with a combination of theory and experimental demonstration leading to, in our opinion, a significant contribution to the field. We present three classes of tunable optical filters, the first of which is an angle-filtering scheme where the stop-band wavelengths are redirected off axis and the passband is transmitted on-axis. This is achieved using a stacked configuration of polarization gratings of various thicknesses. To improve this class of filter, we also introduce a novel optical element, the Bilayer Polarization Grating, exhibiting unique optical properties and demonstrating complex anchoring conditions with high quality. The second class of optical filter is analogous to a Lyot filter, utilizing stacks of static or tunable waveplates sandwiched with polarizing elements. However, we introduce a new configuration using PGs and static waveplates to replace

Unit-cell design for two-dimensional phase-field simulation of microstructure evolution in single-crystal Ni-based superalloys during solidification

Directory of Open Access Journals (Sweden)

Dongjia Cao

2017-12-01

Full Text Available Phase-field simulation serves as an effective tool for quantitative characterization of microstructure evolution in single-crystal Ni-based superalloys during solidification nowadays. The classic unit cell is either limited to γ dendrites along crystal orientation or too ideal to cover complex morphologies for γ dendrites. An attempt to design the unit cell for two-dimensional (2-D phase-field simulations of microstructure evolution in single-crystal Ni-based superalloys during solidification was thus performed by using the MICRESS (MICRostructure Evolution Simulation Software in the framework of the multi-phase-field (MPF model, and demonstrated in a commercial TMS-113 superalloy. The coupling to CALPHAD (CALculation of PHAse Diagram thermodynamic database was realized via the TQ interface and the experimental diffusion coefficients were utilized in the simulation. Firstly, the classic unit cell with a single γ dendrite along crystal orientation was employed for the phase-field simulation in order to reproduce the microstructure features. Then, such simple unit cell was extended into the cases with two other different crystal orientations, i.e., and . Thirdly, for crystal orientations, the effect of γ dendritic orientations and unit cell sizes on microstructure and microsegregation was comprehensively studied, from which a new unit cell with multiple γ dendrites was proposed. The phase-field simulation with the newly proposed unit cell was further performed in the TMS-113 superalloy, and the microstructure features including the competitive growth of γ dendrites, microsegregation of different solutes and distribution of γ′ grains, can be nicely reproduced.

Automatic control unit for A neutron diffraction crystal spectrometer

Energy Technology Data Exchange (ETDEWEB)

Adib, M.; Abbas, Y.; Mostafa, M.; Hamouda, I.

1982-01-01

An automatic transistorized unit has been designed and constructed to control the operation of the double axis crystal spectrometer installed in front of one of the horizontal channels of the ET-RR-1 reactor. The function of the automatic unit is to store the diffracted neutrons at a certain angle with respect to the direction of the incident neutron beam in a selected channel of a 1024-multichannel analyzer for a certain preadjusted time period. AT the end of this time period the unit rotates the spectrometer's arm to another angle, selects the next channel of the MCA and provides the measurement of the diffracted neutron for the same time period. Such a sequence is repeated automatically over all angles required for the neutron diffraction pattern of the sample under investigation. As a result, the stored information at the MCA provides the neutron diffraction pattern as a function of channel number, where each channel corresponds to a certain scattering angle. The stored distribution at MCA can be obtained through the analyzer read out unit. The designed automatic unit has the possibility of providing the neutron diffraction pattern using a 6-digit scaler and a printer.

Ultra-wide tuning single channel filter based on one-dimensional photonic crystal with an air cavity

Science.gov (United States)

Zhao, Xiaodan; Yang, Yibiao; Chen, Zhihui; Wang, Yuncai; Fei, Hongming; Deng, Xiao

2017-02-01

By inserting an air cavity into a one-dimensional photonic crystal of LiF/GaSb, a tunable filter covering the whole visible range is proposed. Following consideration of the dispersion of the materials, through modulating the thickness of the air cavity, we demonstrate that a single resonant peak can shift from 416.1 to 667.3 nm in the band gap at normal incidence by means of the transfer matrix method. The research also shows that the transmittance of the channel can be maximized when the number of periodic LiF/GaSb layers on one side of the air defect layer is equal to that of the other side. When adding a period to both sides respectively, the full width at half maximum of the defect mode is reduced by one order of magnitude. This structure will provide a promising approach to fabricate practical tunable filters in the visible region with ultra-wide tuning range. Project supported by the National Natural Science Foundation of China (Nos. 61575138, 61307069, 51205273), and the Top Young Academic Leaders and the Outstanding Innovative Teams of Higher Learning Institutions of Shanxi.

Laboratory for filter testing

Energy Technology Data Exchange (ETDEWEB)

Paluch, W.

1987-07-01

Filters used for mine draining in brown coal surface mines are tested by the Mine Draining Department of Poltegor. Laboratory tests of new types of filters developed by Poltegor are analyzed. Two types of tests are used: tests of scale filter models and tests of experimental units of new filters. Design and operation of the test stands used for testing mechanical properties and hydraulic properties of filters for coal mines are described: dimensions, pressure fluctuations, hydraulic equipment. Examples of testing large-diameter filters for brown coal mines are discussed.

Sampled data CT system including analog filter and compensating digital filter

International Nuclear Information System (INIS)

Glover, G. H.; DallaPiazza, D. G.; Pelc, N. J.

1985-01-01

A CT scanner in which the amount of x-ray information acquired per unit time is substantially increased by using a continuous-on x-ray source and a sampled data system with the detector. An analog filter is used in the sampling system for band limiting the detector signal below the highest frequency of interest, but is a practically realizable filter and is therefore non-ideal. A digital filter is applied to the detector data after digitization to compensate for the characteristics of the analog filter, and to provide an overall filter characteristic more nearly like the ideal

Tunable ultra-broadband polarization filter based on three-core resonance of the fluid-infiltrated and gold-coated photonic crystal fiber

Science.gov (United States)

Liu, Yingchao; Chen, Hailiang; Ma, Mingjian; Zhang, Wenxun; Wang, Yujun; Li, Shuguang

2018-03-01

We propose a tunable ultra-broadband polarization filter based on three-core resonance of the fluid-infiltrated and gold-coated high birefringent photonic crystal fiber (HB-PCF). Gold film was applied to the inner walls of two cladding air holes and surface plasmon polaritons were generated on its surface. The two gold-coated cladding air holes acted as two defective cores. As the phase matching condition was satisfied, light transmitted in the fiber core and coupled to the two defective cores. The three-core PCF supported three super modes in two orthogonal polarization directions. The coupling characteristics among these modes were investigated using the finite-element method. We found that the coupling wavelengths and strength between these guided modes can be tuned by altering the structural parameters of the designed HB-PCF, such as the size of the voids, thickness of the gold-films and liquid infilling pattern. Under the optimized structural parameters, a tunable broadband polarization filter was realized. For one liquid infilling pattern, we obtained a broadband polarization filter which filtered out the light in y-polarization direction at the wavelength of 1550 nm. For another liquid infilling pattern, we filtered out light in the x-polarization direction at the wavelength of 1310 nm. Our studies on the designed HB-PCF made contributions to the further devising of tunable broadband polarization filters, which are extensively used in telecommunication and sensor systems. Project supported by the National Natural Science Foundation of China (Grant Nos. 61505175 and 61475134) and the Natural Science Foundation of Hebei Province (Grant Nos. F2017203110 and F2017203193).

Graphene-based photonic crystal

International Nuclear Information System (INIS)

Berman, Oleg L.; Boyko, Vladimir S.; Kezerashvili, Roman Ya.; Kolesnikov, Anton A.; Lozovik, Yurii E.

2010-01-01

A novel type of photonic crystal formed by embedding a periodic array of constituent stacks of alternating graphene and dielectric discs into a background dielectric medium is proposed. The photonic band structure and transmittance of such photonic crystal are calculated. The graphene-based photonic crystals can be used effectively as the frequency filters and waveguides for the far infrared region of electromagnetic spectrum. Due to substantial suppression of absorption of low-frequency radiation in doped graphene the damping and skin effect in the photonic crystal are also suppressed. The advantages of the graphene-based photonic crystal are discussed.

Gravity driven and in situ fractional crystallization processes in the Centre Hill complex, Abitibi Subprovince, Canada: Evidence from bilaterally-paired cyclic units

Science.gov (United States)

Thériault, R. D.; Fowler, A. D.

1996-12-01

The formation of layers in mafic intrusions has been explained by various processes, making it the subject of much controversy. The concept that layering originates from gravitational settling of crystals has been superseded in recent years by models involving in situ fractional crystallization. Here we present evidence from the Centre Hill complex that both processes may be operative simultaneously within the same intrusion. The Centre Hill complex is part of the Munro Lake sill, an Archean layered mafic intrusion emplaced in volcanic rocks of the Abitibi Subprovince. The Centre Hill complex comprises the following lithostratigraphic units: six lower cyclic units of peridotite and clinopyroxenite; a middle unit of leucogabbro; six upper cyclic units of branching-textured gabbro (BTG) and clotted-textured gabbro (CTG), the uppermost of these units being overlain by a marginal zone of fine-grained gabbro. The cyclic units of peridotite/clinopyroxenite and BTG/CTG are interpreted to have formed concurrently through fractional crystallization, associated with periodic replenishment of magma to the chamber. The units of peridotite and clinopyroxenite formed by gravitational accumulation of crystals that grew under the roof. The cyclic units of BTG and CTG formed along the upper margin of the sill by two different mechanisms: (1) layers of BTG crystallized in situ along an inward-growing roof and (2) layers of CTG formed by accumulation of buoyant plagioclase crystals. The layers of BTG are characterized by branching pseudomorphs after fayalite up to 50 cm in length that extend away from the upper margin. The original branching crystals are interpreted to have grown from stagnant intercumulus melt in a high thermal gradient resulting from the injection of new magma to the chamber.

Learning about the Unit Cell and Crystal Lattice with Computerized Simulations and Games: A Pilot Study

Science.gov (United States)

Luealamai, Sutha; Panijpan, Bhinyo

2012-01-01

The authors have developed a computer-based learning module on the unit cell of various types of crystal. The module has two components: the virtual unit cell (VUC) part and the subsequent unit cell hunter part. The VUC is a virtual reality simulation for students to actively arrive at the unit cell from exploring, from a broad view, the crystal…

An automatic control unit for A neutron diffraction crystal spectrometer

International Nuclear Information System (INIS)

Adib, M.; Abbas, Y.; Mostafa, M.; Hamouda, I.

1982-01-01

An automatic transistorized unit has been designed and constructed to control the operation of the double axis crystal spectrometer installed in front of one of the horizontal channels of the ET-RR-1 reactor. The function of the automatic unit is to store the diffracted neutrons at a certain angle with respect to the direction of the incident neutron beam in a selected channel of a 1024-multichannel analyzer for a certain preadjusted time period. AT the end of this time period the unit rotates the spectrometer's arm to another angle, selects the next channel of the MCA and provides the measurement of the diffracted neutron for the same time period. Such a sequence is repeated automatically over all angles required for the neutron diffraction pattern of the sample under investigation. As a result, the stored information at the MCA provides the neutron diffraction pattern as a function of channel number, where each channel corresponds to a certain scattering angle. The stored distribution at MCA can be obtained through the analyzer read out unit. The designed automatic unit has the possibility of providing the neutron diffraction pattern using a 6-digit scaler and a printer

Formation and evaluation of convex-curved crystals of lithium fluoride for use in analyzing x-ray spectra

International Nuclear Information System (INIS)

Sellick, B.O.

1976-01-01

Lithium fluoride as received from the vendor in boule form is 38 x 38 x 13 mm thick. This block is cleaved to wafers of the desired thickness, x-ray-evaluated for ''d'' spacing and greatest intensity, bent to the required radius, and then acid-etched to remove foreign material. The diffraction and dispersion characteristics of a wafer are analyzed using well-collimated tungsten x rays that strike the crystal and are diffracted onto no-screen x-ray film. If the crystal is satisfactory, it is mounted in a spectrogoniometer and rotated through an x-ray beam while a detector is set at the optimized angle for the diffracted x rays. The average intensity across the length of the crystal is recorded by multichannel scaling. Any imperfections appear as peaks or dips compared to the average intensity. The crystal next goes to a 10-channel, filter-fluorescer x-ray unit that compares zero-order intensity to diffracted Kα and Kβ intensity. Counts for 100-s intervals are taken in groups of three and averaged. Correction factors for instrument geometry, air, pinhole diameter at zero order, Kα-Kβ, barometric pressure, temperature, etc., are added to the efficiency calculations to obtain the crystal efficiency (epsilon) vs keV data. The crystal is mounted in the spectrograph or spectrometer and calibrated to either the detector or film plane by using direct radiation with proper x-ray filters or absorbers. The crystal is then ready for use

The case for improved HEPA-filter mechanical performance standards revisited

Energy Technology Data Exchange (ETDEWEB)

Ricketts, C.I.; Smith, P.R. [New Mexico State Univ., Las Cruces, NM (United States)

1997-08-01

Under benign operating conditions, High Efficiency Particulate Air (HEPA) filter units serve as reliable and relatively economical components in the air cleaning systems of nuclear facilities worldwide. Despite more than four decades of filter-unit evaluation and improvements, however, the material strength characteristics of the glass fiber filter medium continue to ultimately limit filter functional reliability. In worst-case scenarios involving fire suppression, loss-of-coolant accidents (LOCA`s), or exposure to shock waves or tornado induced flows, rupture of the filter medium of units meeting current qualification standards cannot be entirely ruled out. Even under so-called normal conditions of operation, instances of filter failure reported in the literature leave open questions of filter-unit reliability. Though developments of filter units with improved burst strengths have been pursued outside the United States, support for efforts in this country has been comparatively minimal. This despite user requests for filters with greater moisture resistance, for example. Or the fact that conventional filter designs result in not only the least robust component to be found in a nuclear air cleaning system, but also the one most sensitive to the adverse effects of conditions deviating from those of normal operation. Filter qualification-test specifications of current codes, standards, and regulatory guidelines in the United States are based primarily upon research performed in a 30-year period beginning in the 1950`s. They do not seem to reflect the benefits of the more significant developments and understanding of filter failure modes and mechanisms achieved since that time. One overseas design, based on such knowledge, has proven reliability under adverse operating conditions involving combined and serial challenges. Its widespread use, however, has faltered on a lack of consensus in upgrading filter performance standards. 34 refs., 2 figs., 3 tabs.

International Space Station (ISS) Bacterial Filter Elements (BFEs): Filter Efficiency and Pressure Testing of Returned Units

Science.gov (United States)

Green, Robert D.; Agui, Juan H.; Vijayakumar, R.

2017-01-01

The air revitalization system aboard the International Space Station (ISS) provides the vital function of maintaining a clean cabin environment for the crew and the hardware. This becomes a serious challenge in pressurized space compartments since no outside air ventilation is possible, and a larger particulate load is imposed on the filtration system due to lack of sedimentation due to the microgravity environment in Low Earth Orbit (LEO). The ISS Environmental Control and Life Support (ECLS) system architecture in the U.S. Segment uses a distributed particulate filtration approach consisting of traditional High-Efficiency Particulate Adsorption (HEPA) media filters deployed at multiple locations in each U.S. Segment module; these filters are referred to as Bacterial Filter Elements, or BFEs. These filters see a replacement interval, as part of maintenance, of 2-5 years dependent on location in the ISS. In this work, we present particulate removal efficiency, pressure drop, and leak test results for a sample set of 8 BFEs returned from the ISS after filter replacement. The results can potentially be utilized by the ISS Program to ascertain whether the present replacement interval can be maintained or extended to balance the on-ground filter inventory with extension of the lifetime of ISS beyond 2024. These results can also provide meaningful guidance for particulate filter designs under consideration for future deep space exploration missions.

Study on control of defect mode in hybrid mirror chirped porous silicon photonic crystal

Science.gov (United States)

Chen, Ying; Luo, Pei; Han, Yangyang; Cui, Xingning; He, Lei

2018-03-01

Based on the optical resonance principle and the tight-binding theory, a hybrid mirror chirped porous silicon photonic crystal is proposed. The control of the defect mode in hybrid mirror chirped porous silicon photonic crystal is studied. Through the numerical simulation, the control regulations of the defect modes resulted by the number of the periodical layers for the fundamental unit and the cascading number of the chirped structures are analyzed, and the split and the degeneration of the defect modes resulted by the change of the relative location between the mirror structures and the quasi-mirror structures are discussed. The simulation results show that the band gap would be broadened with the increase of the chirp quantity and the layer number of unilateral chirp. Adjusting the structural parameters of the hybrid mirror structure, the multimode characteristics will occur in the band gap. The more the cascading number of the chirped units, the more the number of the filtering channels will be. In addition, with the increase of the relative location between the mirror structures and the quasi-mirror structures, the degeneration of the defect modes will occur and can obtain high Q value. The structure can provide effective theoretical references for the design the multi-channel filters and high Q value sensors.

Three-dimensional photonic crystals as intermediate filter for thin-film tandem solar cells

Science.gov (United States)

Bielawny, Andreas; Miclea, Paul T.; Wehrspohn, Ralf B.; Lee, Seung-Mo; Knez, Mato; Rockstuhl, Carsten; Lisca, Marian; Lederer, Falk L.; Carius, Reinhard

2008-04-01

The concept of a 3D photonic crystal structure as diffractive and spectrally selective intermediate filter within 'micromorphous' (a-Si/μc-Si) tandem solar cells has been investigated numerically and experimentally. Our device aims for the enhancement of the optical pathway of incident light within the amorphous silicon top cell in its spectral region of low absorption. From our previous simulations, we expect a significant improvement of the tandem cell efficiency of about absolutely 1.3%. This increases the efficiency for a typical a-Si / μc-Si tandem cell from 11.1% to 12.4%, as a result of the optical current-matching of the two junctions. We suggest as wavelength-selective optical element a 3D-structured optical thin-film, prepared by self-organized artificial opal templates and replicated with atomic layer deposition. The resulting samples are highly periodic thin-film inverted opals made of conducting and transparent zinc-oxide. We describe the fabrication processes and compare experimental data on the optical properties in reflection and transmission with our simulations and photonic band structure calculations.

Electrically tunable liquid crystal photonic bandgap fiber laser

DEFF Research Database (Denmark)

Olausson, Christina Bjarnal Thulin; Scolari, Lara; Wei, Lei

2010-01-01

We demonstrate electrical tunability of a fiber laser by using a liquid crystal photonic bandgap fiber. Tuning of the laser is achieved by combining the wavelength filtering effect of a liquid crystal photonic bandgap fiber device with an ytterbium-doped photonic crystal fiber. We fabricate an al...

Filtering of elastic waves by opal-based hypersonic crystal.

Science.gov (United States)

Salasyuk, Alexey S; Scherbakov, Alexey V; Yakovlev, Dmitri R; Akimov, Andrey V; Kaplyanskii, Alexander A; Kaplan, Saveliy F; Grudinkin, Sergey A; Nashchekin, Alexey V; Pevtsov, Alexander B; Golubev, Valery G; Berstermann, Thorsten; Brüggemann, Christian; Bombeck, Michael; Bayer, Manfred

2010-04-14

We report experiments in which high quality silica opal films are used as three-dimensional hypersonic crystals in the 10 GHz range. Controlled sintering of these structures leads to well-defined elastic bonding between the submicrometer-sized silica spheres, due to which a band structure for elastic waves is formed. The sonic crystal properties are studied by injection of a broadband elastic wave packet with a femtosecond laser. Depending on the elastic bonding strength, the band structure separates long-living surface acoustic waves with frequencies in the complete band gap from bulk waves with band frequencies that propagate into the crystal leading to a fast decay.

Advancements in the Interferometric Measurements of Real Time Finishing Birefringent Filter's Crystal Plates

International Nuclear Information System (INIS)

Gan, Ma; Kushtal, Gi; Skomorovsky, Vi; Domyshev, Gn; Sadokhin, Vp

2006-01-01

The finishing of birefringent plates consists of two processes: polishing and evaluation of a surface, which have been performed separately till now. The purpose of this work is achieving of high accuracy of the evaluation and machining of the plane-parallel plates from birefringent crystals, in particular of crystal plates of birefringent filters during their finishing. The developed process combines evaluation and polishing in an interactive way. We have found modes of treatment, shape of polisher, have designed interferometer, with a mirror arranged in polisher. Visual checking of optical thickness comparatively with reference plate was carried out using the interference fringes of equal birefringence, and checking of an optical wedge - by interference rings of an equal inclination. The automated processing of TV camera interference fringes was impossible, because of gaps of interference fringes on polishing cells above the mirror. Therefore a special software was developed for processing of a complex fringe pattern interferogram. Software FastInterf uses furrier analysis technique which allows to process an interferogram with multiply gaps. Interferograms are registered by a high resolution TV camera (1280 x1024). Automatic processing of a fringe interferogram using FastInterf software takes less then one second. The influence of gaps is excluded, and the flat field is taken into account. Software provides full 3D surface and wavefront maps. Aberration analysis of a wavefront gives information on thickness of a plate comparatively with a reference one, optical wedge of plate and azimuth of an inclination of wave front. Moreover, software provides a control of surface quality. The measuring device, features of the software are described and process of interferometric evaluation during polishing is illustrated

Ultra-compact broadband higher order-mode pass filter fabricated in a silicon waveguide for multimode photonics

DEFF Research Database (Denmark)

Guan, Xiaowei; Ding, Yunhong; Frandsen, Lars Hagedorn

2015-01-01

An ultra-compact and broadband higher order-mode pass filter in a 1D photonic crystal silicon waveguide is proposed and experimentally demonstrated. The photonic crystal is designed for the lower order mode to work in the photonic band gap, while the higher order mode is located in the air band....... Consequently, light on the lower order mode is prohibited to pass through the filter, while light on a higher order mode can be converted to a Bloch mode in the photonic crystal and pass through the filter with low insertion loss. As an example, we fabricate a similar to 15-mu m-long first-order-mode pass...

BESSEL FILTER AND CHAOS: THREE-IN-ONE ACTION

DEFF Research Database (Denmark)

Tamaševicius, Arunas; Mykolaitis, Gytis; Bumeliene, Skaidra

2006-01-01

Low-pass active Bessel filters are proposed to be used in a chaotic oscillator. The Bessel unit plays the role of three-in-one: the delay line, the amplifier, and the filter. Results of Spice simulations and hardware experiments are presented.......Low-pass active Bessel filters are proposed to be used in a chaotic oscillator. The Bessel unit plays the role of three-in-one: the delay line, the amplifier, and the filter. Results of Spice simulations and hardware experiments are presented....

CH3SH adsorption properties and mechanism of deodorant filter made of iron hydroxide on porous iron frame; Tetsu takotaisei dasshu filter no methyl mercaptan jokyo seino to jokyo kiko

Energy Technology Data Exchange (ETDEWEB)

Noda, T. [Nippon Steel Corp., Tokyo (Japan)

1998-05-10

It is suggested that methyl mercaptan is decomposed to methyl sulfide and hydrogen by reaction with the a-iron hydroxide, and then the methyl sulfide combines with sulfur crystal and the hydrogen changes into water by the chemical reaction with the {alpha}-iron hydroxide. A deodorant filter was made by treating porous metallic iron with an aqueous solution of L-ascorbic acid, iron (II) sulfate and calcium hydroxide aqueous solution to deposit the iron ascorbate and the {alpha}-iron hydroxide on it. Then the deodorant filter was exposed to the hydrogen sulfide to yield the sulfur crystals on the surface of the deodorant filter. The methyl mercaptan removal capacity of the deodorant filter was studied with repetition of removal tests. Results show that the methyl mercaptan removal capacity of the deodorant filter is a little smaller than that of conventional granular activated carbon. 6 refs., 6 figs., 3 tabs.

The influence of typical ways of operating and air-handling unit on the sensory pollution load from used bag filters

DEFF Research Database (Denmark)

Mysen, M.; Clausen, Geo; Bekö, Gabriel

2003-01-01

An experiment was performed to determine whether the sensory pollution emitted from a bag filter that had been used for 3 months in a suburban area in Denmark was influenced by different ways of operating the air-handling unit (AHU). Samples of the used filter were pre-conditioned to simulate thr...... the airflow outside working hours would significantly increase the sensory pollution emitted by a used bag filter immediately after the AHU is turned on, in comparison with continuous airflow through the AHU (P...... operating conditions: 1) switched off overnight; 2) airflow reduced to 10% overnight; and 3) continuous 100% operation. Outside air passed through the samples and the acceptability of the air after the filter was assessed by a panel of subjects. The results indicate that turning off the AHU or reducing...

Replacement of fluid-filter elements without interruption of flow

Science.gov (United States)

Kotler, R. A.; Ward, J. B.

1969-01-01

Gatling-type filter assembly, preloaded with several filter elements enables filter replacement without breaking into the operative fluid system. When the filter element becomes contaminated, a unit inner subassembly is rotated 60 degrees to position a clean filter in the line.

Laser Rate Equation Based Filtering for Carrier Recovery in Characterization and Communication

DEFF Research Database (Denmark)

Piels, Molly; Iglesias Olmedo, Miguel; Xue, Weiqi

2015-01-01

We formulate a semiconductor laser rate equationbased approach to carrier recovery in a Bayesian filtering framework. Filter stability and the effect of model inaccuracies (unknown or un-useable rate equation coefficients) are discussed. Two potential application areas are explored: laser...... characterization and carrier recovery in coherent communication. Two rate equation based Bayesian filters, the particle filter and extended Kalman filter, are used in conjunction with a coherent receiver to measure frequency noise spectrum of a photonic crystal cavity laser with less than 20 nW of fiber...

An inkjet printed stripe-type color filter of liquid crystal display

International Nuclear Information System (INIS)

Chen, Chin-Tai; Wu, Kuo-Hua; Shieh, Fanny; Lu, Chun-Fu

2010-01-01

In this paper, we propose a comprehensive concept and new design of a drop-on-demand (DOD) inkjet printing process for fabricating color filter (CF) layers of liquid crystal displays (LCDs) onto the structured surfaces of flat substrates, composed of 'physical sidewalls' for aligning and controlling the liquid morphology. Several fundamental guidelines of the design have been addressed in current inkjet-printing techniques. Using a droplet generator (printhead) of the deposition system, the color-ink drops can be jetted and placed over the specific domains, where the sidewalls align the flow merged from a stream of droplets and fulfill the coverage of the defined areas, in which the geometrical relations correlating the droplets and sidewalls are explicitly expressed in the study. According to the results of the simulation and analysis, the proposed sidewalls, acting as the physical barriers, can control the liquid morphology through the simple geometric factors such as sidewall widths, heights and contact angles. The experimental results showed that the solid RGB color layers were self-assembled from the liquid droplets and formed with the uniform thickness, except for the neighborhood of the sidewalls. It indicated that the sidewalls serving as 'physical barriers' had a remarkable effect in confining and self-aligning the droplet flow within the desirable regions. This inkjet-printing method would alternatively offer one cost-effective and high-flexibility method for the production of the versatile LCD CF, thus being particularly beneficial for large-area printing and flexible substrates.

Autonomous control of inverter-interfaced Distributed Generation units for harmonic current filtering and resonance damping in an islanded microgrid

DEFF Research Database (Denmark)

Wang, Xiongfei; Blaabjerg, Frede; Chen, Zhe

2012-01-01

Harmonic current filtering and resonance damping have become important concerns on the control of an islanded microgrids. To address these challenges, this paper proposes a control method of inverter-interfaced Distributed Generation (DG) units, which can autonomously share harmonic currents and ...

MST Filterability Tests

Energy Technology Data Exchange (ETDEWEB)

Poirier, M. R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Burket, P. R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Duignan, M. R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2015-03-12

The Savannah River Site (SRS) is currently treating radioactive liquid waste with the Actinide Removal Process (ARP) and the Modular Caustic Side Solvent Extraction Unit (MCU). The low filter flux through the ARP has limited the rate at which radioactive liquid waste can be treated. Recent filter flux has averaged approximately 5 gallons per minute (gpm). Salt Batch 6 has had a lower processing rate and required frequent filter cleaning. Savannah River Remediation (SRR) has a desire to understand the causes of the low filter flux and to increase ARP/MCU throughput. In addition, at the time the testing started, SRR was assessing the impact of replacing the 0.1 micron filter with a 0.5 micron filter. This report describes testing of MST filterability to investigate the impact of filter pore size and MST particle size on filter flux and testing of filter enhancers to attempt to increase filter flux. The authors constructed a laboratory-scale crossflow filter apparatus with two crossflow filters operating in parallel. One filter was a 0.1 micron Mott sintered SS filter and the other was a 0.5 micron Mott sintered SS filter. The authors also constructed a dead-end filtration apparatus to conduct screening tests with potential filter aids and body feeds, referred to as filter enhancers. The original baseline for ARP was 5.6 M sodium salt solution with a free hydroxide concentration of approximately 1.7 M.3 ARP has been operating with a sodium concentration of approximately 6.4 M and a free hydroxide concentration of approximately 2.5 M. SRNL conducted tests varying the concentration of sodium and free hydroxide to determine whether those changes had a significant effect on filter flux. The feed slurries for the MST filterability tests were composed of simple salts (NaOH, NaNO₂, and NaNO₃) and MST (0.2 – 4.8 g/L). The feed slurry for the filter enhancer tests contained simulated salt batch 6 supernate, MST, and filter enhancers.

B Plant exhaust filter inventory analysis

International Nuclear Information System (INIS)

Lan, J.S.; Wootan, D.W.; Carter, L.L.; Bunch, W.L.; Covey, L.I.; Greenborg, J.

1994-10-01

This paper describes a method for determining radionuclide inventories in filters using measurements of radiation fields that determine photon dose rates and photon-plus-electron dose rates between filter banks. The mathematical approach quantifies the curie inventories of filter banks by using the measured dose rates and the calculated Green's functions involving detector responses per unit source

Higher-order chaotic oscillator using active bessel filter

DEFF Research Database (Denmark)

Lindberg, Erik; Mykolaitis, Gytis; Bumelien, Skaidra

2010-01-01

A higher-order oscillator, including a nonlinear unit and an 8th-order low-pass active Bessel filter is described. The Bessel unit plays the role of "three-in-one": a delay line, an amplifier and a filter. Results of hardware experiments and numerical simulation are presented. Depending...

Fresnel Lenses fabricated by femtosecond laser micromachining on Polymer 1D Photonic Crystal

Directory of Open Access Journals (Sweden)

Guduru Surya S.K.

2013-11-01

Full Text Available We report the fabrication of micro Fresnel lenses by femtosecond laser surface ablation on polymer 1D photonic crystals. This device is designed to focus the transmitted wavelength of the photonic crystal and filter the wavelengths corresponding to the photonic band gap region. Integration of such devices in a wavelength selective light harvesting and filtering microchip can be achieved.

Progress towards the use of disposable filters

International Nuclear Information System (INIS)

Macphail, I.

1979-08-01

Thermally degradable materials have been evaluated for service in HEPA filter units used to filter gases from active plants. The motivation was to reduce the bulk storage problems of contaminated filters by thermal decomposition to gaseous products and a solid residue substantially comprised of the filtered particulates. It is shown that while there are no commercially available alternatives to the glass fibre used in the filter medium, it would be feasible to manufacture the filter case and spacers from materials which could be incinerated. Operating temperatures, costs and the type of residues for disposal are discussed for filter case materials. (U.K.)

Field evaluation of prototype electrofibrous filters

International Nuclear Information System (INIS)

Kuhl, W.D.; Bergman, W.; Biermann, A.H.; Lum, B.Y.

1982-01-01

New prototype electrofibrous filters were designed, built and evaluated in laboratory tests and in field installations. Two prototypes were designed for use in nuclear ventilation ducts as prefilters to HEPA filters. One prototype is designed to be a permanent component of the ventilation system while the other is a disposable unit. The disposable electrofibrous prefilter was installed in the exhaust stream of a glove box in which barrels of uranium turnings are burned. Preliminary tests show the disposal prefilter is effectively prolonging the HEPA filter life. An earlier prototype of the rolling prefilter was upgraded to meet the increased requirements for installation in a nuclear facility. This upgraded prototype was evaluated in the fire test facility at LLNL and shown to be effective in protecting HEPA filters from plugging under the most severe smoke conditions. The last prototype described in this report is a recirculating air filter. After demonstrating a high performance in laboratory tests the unit was shipped to Savannah River where it is awaiting installation in a Pu fuel fabrication facility. An analysis of the particulate problem in Savannah River indicates that four recirculating air filter will save $172,000 per year in maintenance costs

Amplifying and compressing optical filter based on one-dimensional ternary photonic crystal structure containing gain medium

Science.gov (United States)

Jamshidi-Ghaleh, Kazem; Ebrahimpour, Zeinab; Moslemi, Fatemeh

2015-07-01

The transmission spectrum properties of the one-dimensional ternary photonic crystal (1DTPC) structure, composed of dielectric (D), metal (M) and gain (G) materials, with three different arrangements of (DGM)N, (GDM)N and (DMG)N, where N is the number of periodicity, were investigated. Two full photonic band gaps and N-1 resonant peaks, localized between them, were observed on transmittance spectra on near-UV spectrum region. When the gained layer was placed in front of the metal, the peaks appeared with higher resolution. There is a peak, localized on the higher band-edge of the first gap, which shows very interesting property than the other peaks. Thus, it amplifies and compresses faster with increase in the N and strength of the gain coefficient. The effects of the gain coefficient and periodicity number are graphically illustrated. This communication presents a PC structure that can be a good candidate to design an amplifying and compressing single or multi-channel optical filter in the UV region.

Frequency tunability of solid-core photonic crystal fibers filled with nanoparticle-doped liquid crystals

OpenAIRE

Scolari, Lara; Gauza, Sebastian; Xianyu, Haiqing; Zhai, Lei; Eskildsen, Lars; Alkeskjold, Thomas Tanggaard; Wu, Shin-Tson; Bjarklev, Anders Overgaard

2009-01-01

We infiltrate liquid crystals doped with BaTiO3 nanoparticles in a photonic crystal fiber and compare the measured transmission spectrum with the one achieved without dopant. New interesting features, such as frequency modulation response of the device and a transmission spectrum with tunable attenuation on the short wavelength side of the widest bandgap, suggest a potential application of this device as a tunable all-in-fiber gain equalization filter with an adjustable slope. The tunability ...

Experimental use of iteratively designed rotation invariant correlation filters

International Nuclear Information System (INIS)

Sweeney, D.W.; Ochoa, E.; Schils, G.F.

1987-01-01

Iteratively designed filters are incorporated into an optical correlator for position, rotation, and intensity invariant recognition of target images. The filters exhibit excellent discrimination because they are designed to contain full information about the target image. Numerical simulations and experiments demonstrate detection of targets that are corrupted with random noise (SNR≅0.5) and also partially obscured by other objects. The complex valued filters are encoded in a computer generated hologram and fabricated directly using an electron-beam system. Experimental results using a liquid crystal spatial light modulator for real-time input show excellent agreement with analytical and numerical computations

78 FR 79709 - Duke Energy Florida, Inc., Crystal River Unit 3 Nuclear Generating Plant Post-Shutdown...

Science.gov (United States)

2013-12-31

... NUCLEAR REGULATORY COMMISSION [Docket No. 50-302; NRC-2013-0283] Duke Energy Florida, Inc., Crystal River Unit 3 Nuclear Generating Plant Post-Shutdown Decommissioning Activities Report AGENCY: Nuclear Regulatory Commission (NRC). ACTION: Notice of receipt; availability; public meeting; and request...

Factors Influencing HEPA Filter Performance

International Nuclear Information System (INIS)

Parsons, M.S.; Waggoner, Ch.A.

2009-01-01

Properly functioning HEPA air filtration systems depend on a variety of factors that start with the use of fully characterized challenge conditions for system design and then process control during operation. This paper addresses factors that should be considered during the design phase as well as operating parameters that can be monitored to ensure filter function and lifetime. HEPA filters used in nuclear applications are expected to meet design, fabrication, and performance requirements set forth in the ASME AG-1 standard. The DOE publication Nuclear Air Cleaning Handbook (NACH) is an additional guidance document for design and operation HEPA filter systems in DOE facilities. These two guidelines establish basic maximum operating parameters for temperature, maximum aerosol particle size, maximum particulate matter mass concentration, acceptable differential pressure range, and filter media velocity. Each of these parameters is discussed along with data linking variability of each parameter with filter function and lifetime. Temporal uncertainty associated with gas composition, temperature, and absolute pressure of the air flow can have a direct impact on the volumetric flow rate of the system with a corresponding impact on filter media velocity. Correlations between standard units of flow rate (standard meters per minute or cubic feet per minute) versus actual units of volumetric flow rate are shown for variations in relative humidity for a 70 deg. C to 200 deg. C temperature range as an example of gas composition that, uncorrected, will influence media velocity. The AG-1 standard establishes a 2.5 cm/s (5 feet per minute) ceiling for media velocities of nuclear grade HEPA filters. Data are presented that show the impact of media velocities from 2.0 to 4.0 cm/s media velocities (4 to 8 fpm) on differential pressure, filter efficiency, and filter lifetime. Data will also be presented correlating media velocity effects with two different particle size

Advancements in the Interferometric Measurements of Real Time Finishing Birefringent Filter's Crystal Plates

Energy Technology Data Exchange (ETDEWEB)

Gan, Ma [State Optical Institute, Birzhevaya linia, 12 St. Petersburg (Russian Federation); Kushtal, Gi; Skomorovsky, Vi; Domyshev, Gn; Sadokhin, Vp [Institute of Solar-Terrestrial Physics Siberian Branch of Russian Academy of Sciences, 126 Lermontova Str., PO 4026, 664033, Irkutsk (Russian Federation)

2006-10-15

The finishing of birefringent plates consists of two processes: polishing and evaluation of a surface, which have been performed separately till now. The purpose of this work is achieving of high accuracy of the evaluation and machining of the plane-parallel plates from birefringent crystals, in particular of crystal plates of birefringent filters during their finishing. The developed process combines evaluation and polishing in an interactive way. We have found modes of treatment, shape of polisher, have designed interferometer, with a mirror arranged in polisher. Visual checking of optical thickness comparatively with reference plate was carried out using the interference fringes of equal birefringence, and checking of an optical wedge - by interference rings of an equal inclination. The automated processing of TV camera interference fringes was impossible, because of gaps of interference fringes on polishing cells above the mirror. Therefore a special software was developed for processing of a complex fringe pattern interferogram. Software FastInterf uses furrier analysis technique which allows to process an interferogram with multiply gaps. Interferograms are registered by a high resolution TV camera (1280 x1024). Automatic processing of a fringe interferogram using FastInterf software takes less then one second. The influence of gaps is excluded, and the flat field is taken into account. Software provides full 3D surface and wavefront maps. Aberration analysis of a wavefront gives information on thickness of a plate comparatively with a reference one, optical wedge of plate and azimuth of an inclination of wave front. Moreover, software provides a control of surface quality. The measuring device, features of the software are described and process of interferometric evaluation during polishing is illustrated.

Graphic filter library implemented in CUDA language

OpenAIRE

Peroutková, Hedvika

2009-01-01

This thesis deals with the problem of reducing computation time of raster image processing by parallel computing on graphics processing unit. Raster image processing thereby refers to the application of graphic filters, which can be applied in sequence with different settings. This thesis evaluates the suitability of using parallelization on graphic card for raster image adjustments based on multicriterial choice. Filters are implemented for graphics processing unit in CUDA language. Opacity ...

Compact Liquid Crystal Based Tunable Band-Stop Filter with an Ultra-Wide Stopband by Using Wave Interference Technique

Directory of Open Access Journals (Sweden)

Longzhu Cai

2017-01-01

Full Text Available A wave interference filtering section that consists of three stubs of different lengths, each with an individual stopband of its own central frequency, is reported here for the design of band-stop filters (BSFs with ultra-wide and sharp stopbands as well as large attenuation characteristics. The superposition of the individual stopbands provides the coverage over an ultra-wide frequency range. Equations and guidelines are presented for the application of a new wave interference technique to adjust the rejection level and width of its stopband. Based on that, an electrically tunable ultra-wide stopband BSF using a liquid crystal (LC material for ultra-wideband (UWB applications is designed. Careful treatment of the bent stubs, including impedance matching of the main microstrip line and bent stubs together with that of the SMA connectors and impedance adaptors, was carried out for the compactness and minimum insertion and reflection losses. The experimental results of the fabricated device agree very well with that of the simulation. The centre rejection frequency as measured can be tuned between 4.434 and 4.814 GHz when a biased voltage of 0–20 Vrms is used. The 3 dB and 25 dB stopband bandwidths were 4.86 GHz and 2.51 GHz, respectively, which are larger than that of other recently reported LC based tunable BSFs.

Multistage parallel-serial time averaging filters

International Nuclear Information System (INIS)

Theodosiou, G.E.

1980-01-01

Here, a new time averaging circuit design, the 'parallel filter' is presented, which can reduce the time jitter, introduced in time measurements using counters of large dimensions. This parallel filter could be considered as a single stage unit circuit which can be repeated an arbitrary number of times in series, thus providing a parallel-serial filter type as a result. The main advantages of such a filter over a serial one are much less electronic gate jitter and time delay for the same amount of total time uncertainty reduction. (orig.)

Development of a neutron irradiation device with a cooled crystal filter: Radiation physical properties and applications in in vivo irradiations

International Nuclear Information System (INIS)

Braetter, P.; Galinke, E.; Gatschke, W.; Gawlik, D.; Roesick, U.

1979-01-01

The radiation-physical and geometrical properties of a neutron-beam, collimated with a Bi-crystal filter were investigated at the reactor BER II. The influence of the crystal temperature as well as the actions of a reflector and a collimator on neutron flux-density and neutron field of the thermal neutrons were investigated. The dose contributions of the thermal, epithermal and fast neutrons as well as γ-radiation was determined by activation of the sample respective with TLD-measurements. The influence of irradiation and measurement geometry on the sensitivity and detection probability was investigated by means of phantom irradiations. The method prooved to be suitable, to detect changes of the Ca-content in a rat hind leg by about 10%. In investigations on animal groups of about 10 animals a threshold of detectability for changes of the ca-content is to be expected by about 4%. In a further group experiment it was found, that even in the case of multiple radiation the procedure of irradiation and measurement was not followed by a significant change in the Ca-content of the hind legs of the testing animals. (orig.) [de

Electrically Tuned Microwave Devices Using Liquid Crystal Technology

Directory of Open Access Journals (Sweden)

Pouria Yaghmaee

2013-01-01

Full Text Available An overview of liquid crystal technology for microwave and millimeter-wave frequencies is presented. The potential of liquid crystals as reconfigurable materials arises from their ability for continuous tuning with low power consumption, transparency, and possible integration with printed and flexible circuit technologies. This paper describes physical theory and fundamental electrical properties arising from the anisotropy of liquid crystals and overviews selected realized liquid crystal devices, throughout four main categories: resonators and filters, phase shifters and delay lines, antennas, and, finally, frequency-selective surfaces and metamaterials.

Principles of crystallization, and methods of single crystal growth

International Nuclear Information System (INIS)

Chacra, T.

2010-01-01

Most of single crystals (monocrystals), have distinguished optical, electrical, or magnetic properties, which make from single crystals, key elements in most of technical modern devices, as they may be used as lenses, Prisms, or grating sin optical devises, or Filters in X-Ray and spectrographic devices, or conductors and semiconductors in electronic, and computer industries. Furthermore, Single crystals are used in transducer devices. Moreover, they are indispensable elements in Laser and Maser emission technology.Crystal Growth Technology (CGT), has started, and developed in the international Universities and scientific institutions, aiming at some of single crystals, which may have significant properties and industrial applications, that can attract the attention of international crystal growth centers, to adopt the industrial production and marketing of such crystals. Unfortunately, Arab universities generally, and Syrian universities specifically, do not give even the minimum interest, to this field of Science.The purpose of this work is to attract the attention of Crystallographers, Physicists and Chemists in the Arab universities and research centers to the importance of crystal growth, and to work on, in the first stage to establish simple, uncomplicated laboratories for the growth of single crystal. Such laboratories can be supplied with equipment, which are partly available or can be manufactured in the local market. Many references (Articles, Papers, Diagrams, etc..) has been studied, to conclude the most important theoretical principles of Phase transitions,especially of crystallization. The conclusions of this study, are summarized in three Principles; Thermodynamic-, Morphologic-, and Kinetic-Principles. The study is completed by a brief description of the main single crystal growth methods with sketches, of equipment used in each method, which can be considered as primary designs for the equipment, of a new crystal growth laboratory. (author)

Remote aerosol testing of large size HEPA filter banks

International Nuclear Information System (INIS)

Franklin, B.; Pasha, M.; Bronger, C.A.

1987-01-01

Different methods of testing HEPA filter banks are described. Difficulties in remote testing of large banks of HEPA filters in series with minimum distances between banks, and with no available access upstream and downstream of the filter house, are discussed. Modifications incorporated to make the filter system suitable for remote testing without personnel re-entry into the filter house are described for a 51,000 m/sup 3//hr filter unit at the WIPP site

Pyrolytic graphite as an efficient second-order neutron filter at tuned positions of boundary crossing

International Nuclear Information System (INIS)

Adib, M.; Abdel Kawy, A.; Habib, N.; El Mesiry, M.

2010-01-01

An investigation of pyrolytic graphite (PG) crystal as an efficient second order neutron filter at tuned boundary crossings has been carried out. The neutron transmission through PG crystal at these tuned crossing points as a function of first- and second-order wavelengths were calculated in terms of PG mosaic spread and thickness. The filtering features of PG crystals at these tuned boundary crossings were deduced. It was shown that, there are a large number of tuned positions at double and triple boundary crossings of the curves (hkl) are very promising as tuned filter positions. However, only fourteen of them are found to be most promising ones. These tuned positions are found to be within the neutron wavelengths from 0.133 up to 0.4050 nm. A computer package GRAPHITE has been used in order to provide the required calculations in the whole neutron wavelength range in terms of PG mosaic spread and its orientation with respect to incident neutron beam direction. It was shown that 0.5 cm thick PG crystal with angular mosaic spread of 2 0 is sufficient to remove 2nd-order neutrons at the wavelengths corresponding to the positions of the intersection boundaries curves (hkl).

The statistical bandwidth of Butterworth filters

Science.gov (United States)

Davy, J. L.; Dunn, I. P.

1987-06-01

The precision of standard architectural acoustic measurements is a function of the statistical bandwidth of the band pass filters used in the measurements. The International and United States Standards on octave and fractional octave-band filters which specify the band pass filters used in architectural acoustics measurements give the effective bandwidth, but unfortunately not the statistical bandwidth of the filters. Both these Standards are currently being revised and both revisions require the use of Butterworth filter characteristics. In this paper it is shown theoretically that the ratio of statistical bandwidth to effective bandwidth for an nth order Butterworth band pass filter is {2n}/{(2n-1)}. This is verified experimentally for third-octave third-order Butterworth band pass filters. It is also shown experimentally that this formula is approximately correct for some non-Butterworth third-octave third-order band pass filters. Because of the importance of Butterworth filters in the revised Standards, the theory of Butterworth filters is reviewed and the formulae for Butterworth filters given in both revised Standards are derived.

Structural testing of salt loaded HEPA filters for WIPP

International Nuclear Information System (INIS)

Smith, P.R.; Leslie, I.H.; Hensel, E.C.; Shultheis, T.M.; Walls, J.R.

1993-01-01

The ventilation studies of the Waste Isolation Pilot Plant described in this paper were performed by personnel from New Mexico State Univ. in collaboration with Sandia National Laboratories, Los Alamos National Laboratory and Westinghouse Corporation. High efficiency particulate air filters (0.61m by 0.61m by 0.3m) of the type in use at the Waste Isolation Pilot Plant were loaded with salt aerosol provided from that site. The structural strength of salt-loaded, high-efficiency filters was investigated at two humidity levels, high (75%RH) and low (13-14% RH), by subjecting the filters to pressure transients of the types expected from tornadoes. Filters loaded under the high humidity condition proved to have a greater structural strength than did the filters loaded under the low humidity conditions, when both types were subjected to tornado-like pressure pulses. This unexpected results was apparently due to the crystallization of salt upon the wire face guard of the HEPA filter loaded under the high humidity condition which kept salt from penetrating the filter medium while still providing a substantial pressure drop at the standard flow rate. Results are also presented for HEPA filters pre-conditioned at 100% RH before structural testing and for HEPA filters in series with pre-filters

Amplifying and compressing optical filter based on one-dimensional ternary photonic crystal structure containing gain medium

Energy Technology Data Exchange (ETDEWEB)

Jamshidi-Ghaleh, Kazem, E-mail: k-jamshidi@azaruinv.ac.ir [Department of Physics, Azarbaijan Shahid Madani University, Tabriz (Iran, Islamic Republic of); Ebrahimpour, Zeinab [Department of Physics, Shahid Beheshti University, Evin 19839 Tehran (Iran, Islamic Republic of); Moslemi, Fatemeh [Department of Physics, Azarbaijan Shahid Madani University, Tabriz (Iran, Islamic Republic of)

2015-07-15

The transmission spectrum properties of the one-dimensional ternary photonic crystal (1DTPC) structure, composed of dielectric (D), metal (M) and gain (G) materials, with three different arrangements of (DGM){sup N}, (GDM){sup N} and (DMG){sup N}, where N is the number of periodicity, were investigated. Two full photonic band gaps and N−1 resonant peaks, localized between them, were observed on transmittance spectra on near-UV spectrum region. When the gained layer was placed in front of the metal, the peaks appeared with higher resolution. There is a peak, localized on the higher band-edge of the first gap, which shows very interesting property than the other peaks. Thus, it amplifies and compresses faster with increase in the N and strength of the gain coefficient. The effects of the gain coefficient and periodicity number are graphically illustrated. This communication presents a PC structure that can be a good candidate to design an amplifying and compressing single or multi-channel optical filter in the UV region.

Rotation speed measurement for turbine governor: torsion filtering by using Kalman filter

International Nuclear Information System (INIS)

Houry, M.P.; Bourles, H.

1995-11-01

The rotation speed of a turbogenerator is disturbed by its shaft torsion. Obtaining a filtered measure of this sped a problem of a great practical importance for turbine governor. A good filtering of this speed must meet two requirements: it must cut frequencies of the shaft torsion oscillation and it must not reduce or delay the signal in the pass-band. i.e. at lower frequencies. At Electricite de France, the speed measure is used to set in motion the fast valving system as quickly as possible, after a short circuit close to the unit (to contribute to the stability) or after an islanding (to quickly reach a balance with the house load). It is difficult to satisfy these two requirements by using conventional filtering methods. The standard solution consists in a first order filter: at Electricite de France, its time constant is equal to 80 ms; We have decided to improve this filtering by designing a new filter which cuts the frequencies of the shaft torsion oscillation without reducing the bandwidth of the speed measure. If one uses conventional methods to obtain a band-stop filter (for instance a Butterworth, a Chebyshev or an elliptic band-stop filter),it is easy to obtain the desired magnitude but not a phase near zero in the whole pass-band. Therefore, we have chosen to design the filter by using Kalman's theory. The measurement noise is modeled as a colored one, generated by a very lightly damped system driven by a white noise. The resulting Kalman filter is an effective band-stop filter, whose phase nicely remains near zero in the whole pass-band. (authors). 13 refs., 12 figs

Development of Filter-Blower Unit for use in the Advanced Nuclear Biological Chemical Protection System (ANBCPS) Helicopter/Transport-aircraft version

NARCIS (Netherlands)

Sabel, R.; Reffeltrath, P.A.; Jonkman, A.; Post, T.

2006-01-01

As a participant in the three-nation partnership for development of the ANBCP-S for use in Helicopters, Transport Aircraft and Fast Jet, the Royal Netherlands Airforce (RNLAF) picked up the challenge to design a Filter- Blower-Unit (FBU). Major Command (MajCom) of the RNLAF set priority to develop a

A new method of liquid crystal thermometry excluding human color sensation

International Nuclear Information System (INIS)

Kunugi, Tomoaki; Akino, Norio; Ueda, Masaharu.

1987-01-01

Some choresteric liquid crystals can be used as a thermometer because of their color changes with varying temperatures. However, it is impossible to employ human color sensation for precise quantitative evaluation of temperature from their color. Therefore, a new method of liquid crystal thermometry is developed using narrow band optical filters and an image processor to exclude the employment of human color sensation. Relations between filter wavelength and temperature were determined by calibration tests. Two dimensional temperature distributions on a heated plate were successfully measured by the present method. (author)

Crystallization and crystal manipulation of a steric chaperone in complex with its lipase substrate

International Nuclear Information System (INIS)

Pauwels, Kris; Loris, Remy; Vandenbussche, Guy; Ruysschaert, Jean-Marie; Wyns, Lode; Van Gelder, Patrick

2005-01-01

Crystals of the lipase of B. glumae in complex with its specific foldase were obtained in two forms. Crystallization, crystal manipulation and preliminary X-ray diffraction analysis are described. Bacterial lipases that are secreted via the type II secretion pathway require a lipase-specific foldase in order to obtain their native and biologically active conformation in the periplasmic space. The lipase–foldase complex from Burkholderia glumae (319 and 333 residues, respectively) was crystallized in two crystal forms. One crystal form belongs to space group P3 1 21 (P3 2 21), with unit-cell parameters a = b = 122.3, c = 98.2 Å. A procedure is presented which improved the diffraction of these crystals from ∼5 to 2.95 Å. For the second crystal form, which belonged to space group C2 with unit-cell parameters a = 183.0, b = 75.7, c = 116.6 Å, X-ray data were collected to 1.85 Å

Behavior of HEPA filters under high humidity airflows

International Nuclear Information System (INIS)

Ricketts, C.I.

1992-10-01

To help determine and improve the safety margins of High Efficiency Particulate Air (HEPA) filter units in nuclear facilities under possible accident conditions, the structural limits and failure mechanisms of filter in high-humidity airflows were established and the fundamental physical phenomena underlying filter failure or malfunction in humid air were identified. Empirical models for increases in filter pressure drop with time in terms of the relevant airstream parameters were also developed. The weaknesses of currently employed humidity countermeasures used in filter protection are discussed and fundamental explanations for reported filter failures in normal service are given. (orig./DG) [de

Recirculating electric air filter for use in confined spaces

International Nuclear Information System (INIS)

Bergman, W.; Biermann, A.; Kuhl, W.

1985-01-01

We have developed recirculating electric air filters for use in confined spaces where the existing ventilation system is not adequate for removing suspended particles. Two experimental filters were built and evaluated, both of which consisted of a cylindrical cartridge filter fitted over an air blower. In one design the cylindrical cartridge is a disposable unit with the electrodes and filter medium built as an integrated unit. The second design has a cylindrical cartridge that can be easily disassembled to allow replacement of the filter medium. Both designs were evaluated in a 354-ft 3 test cell using NaCl aerosols. The second design was installed and evaluated in a chamber where highly radioactive 238 PuO 2 powder is formed into pellets. We have derived equations that describe the theory of recirculating air filters. The predicted performance compares well with experimental measurements under controlled conditions. 2 refs., 7 figs., 1 tab. (DT)

Photonic Crystals Towards Nanoscale Photonic Devices

CERN Document Server

Lourtioz, Jean-Michel; Berger, Vincent; Gérard, Jean-Michel; Maystre, Daniel; Tchelnokov, Alexei; Pagnoux, Dominique

2008-01-01

Just like the periodical crystalline potential in solid state crystals determines their properties for the conduction of electrons, the periodical structuring of photonic crystals leads to envisioning the possibility of achieving a control of the photon flux in dielectric and metallic materials. The use of photonic crystals as cages for storing, filtering or guiding light at the wavelength scale paves the way to the realization of optical and optoelectronic devices with ultimate properties and dimensions. This will contribute towards meeting the demands for greater miniaturization imposed by the processing of an ever increasing number of data. Photonic Crystals will provide students and researchers from different fields with the theoretical background required for modelling photonic crystals and their optical properties, while at the same time presenting the large variety of devices, ranging from optics to microwaves, where photonic crystals have found application. As such, it aims at building bridges between...

Photonic Crystals Towards Nanoscale Photonic Devices

CERN Document Server

Lourtioz, Jean-Michel; Berger, Vincent; Gérard, Jean-Michel; Maystre, Daniel; Tchelnokov, Alexis

2005-01-01

Just like the periodical crystalline potential in solid-state crystals determines their properties for the conduction of electrons, the periodical structuring of photonic crystals leads to envisioning the possibility of achieving a control of the photon flux in dielectric and metallic materials. The use of photonic crystals as a cage for storing, filtering or guiding light at the wavelength scale thus paves the way to the realisation of optical and optoelectronic devices with ultimate properties and dimensions. This should contribute toward meeting the demands for a greater miniaturisation that the processing of an ever increasing number of data requires. Photonic Crystals intends at providing students and researchers from different fields with the theoretical background needed for modelling photonic crystals and their optical properties, while at the same time presenting the large variety of devices, from optics to microwaves, where photonic crystals have found applications. As such, it aims at building brid...

Particle Filtering Methods for Incorporating Intelligence Updates

Science.gov (United States)

2017-03-01

past time steps. 3.2.1 Particle Filtering through Bayesian Bootstrap Sampling Although SIS helps resolve the computational and complexity issues...variables. This insight was called the Bayesian bootstrap filter, or more commonly called the particle filter. Multiple particles are sampled from an...2012) 16 maps of drug flow into the United States. Business Insider Online, (July 8), http://www.businessinsider.com/16-maps-of-drug-flow-into-the

Large three-dimensional photonic crystals based on monocrystalline liquid crystal blue phases.

Science.gov (United States)

Chen, Chun-Wei; Hou, Chien-Tsung; Li, Cheng-Chang; Jau, Hung-Chang; Wang, Chun-Ta; Hong, Ching-Lang; Guo, Duan-Yi; Wang, Cheng-Yu; Chiang, Sheng-Ping; Bunning, Timothy J; Khoo, Iam-Choon; Lin, Tsung-Hsien

2017-09-28

Although there have been intense efforts to fabricate large three-dimensional photonic crystals in order to realize their full potential, the technologies developed so far are still beset with various material processing and cost issues. Conventional top-down fabrications are costly and time-consuming, whereas natural self-assembly and bottom-up fabrications often result in high defect density and limited dimensions. Here we report the fabrication of extraordinarily large monocrystalline photonic crystals by controlling the self-assembly processes which occur in unique phases of liquid crystals that exhibit three-dimensional photonic-crystalline properties called liquid-crystal blue phases. In particular, we have developed a gradient-temperature technique that enables three-dimensional photonic crystals to grow to lateral dimensions of ~1 cm (~30,000 of unit cells) and thickness of ~100 μm (~ 300 unit cells). These giant single crystals exhibit extraordinarily sharp photonic bandgaps with high reflectivity, long-range periodicity in all dimensions and well-defined lattice orientation.Conventional fabrication approaches for large-size three-dimensional photonic crystals are problematic. By properly controlling the self-assembly processes, the authors report the fabrication of monocrystalline blue phase liquid crystals that exhibit three-dimensional photonic-crystalline properties.

Optical properties of mesoporous photonic crystals, filled with dielectrics, ferroelectrics and piezoelectrics

Directory of Open Access Journals (Sweden)

V. S. Gorelik

2017-12-01

Full Text Available At present, it is very important to create new types of mirrors, nonlinear light frequency transformers and optical filters with controlled optical properties. In this connection, it is of great interest to study photonic crystals. Their dielectric permittivity varies periodically in space with a period permitting Bragg diffraction of light. In this paper, we have investigated the optical properties of mesoporous three-dimensional (3D opal-type and one-dimensional (1D anodic alumina photonic crystals, filled with different dielectrics, ferroelectrics and piezoelectrics. We have compared the optical properties of initial mesoporous photonic crystals and filled with different substances. The possibility of mesoporous photonic crystals using selective narrow-band light filters in Raman scattering experiments and nonlinear mirrors has been analyzed. The electromagnetic field enhancing in the case of exciting light frequency close to the stop band edges has been established. The optical harmonics and subharmonics generation in mesoporous crystals, filled with ferroelectrics and piezoelectrics was proposed.

Demonstration of a single-crystal reflector-filter for enhancing slow neutron beams

DEFF Research Database (Denmark)

Muhrer, G.; Schonfeldt, T.; Iverson, E. B.

2016-01-01

The cold polycrystalline beryllium reflector-filter concept has been used to enhance the cold neutron emission of cryogenic hydrogen moderators, while suppressing the intermediate wavelength and fast neutron emission at the same time. While suppressing the fast neutron emission is often desired, ......-filter benefits arise from its interaction with fast (background) neutrons, not with intermediate wavelength neutrons of potential interest in many types of neutron scattering. (C) 2016 Elsevier B.V. All rights reserved....

An Innovative Strategy for Accurate Thermal Compensation of Gyro Bias in Inertial Units by Exploiting a Novel Augmented Kalman Filter

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Rita Fontanella

2018-05-01

Full Text Available This paper presents an innovative model for integrating thermal compensation of gyro bias error into an augmented state Kalman filter. The developed model is applied in the Zero Velocity Update filter for inertial units manufactured by exploiting Micro Electro-Mechanical System (MEMS gyros. It is used to remove residual bias at startup. It is a more effective alternative to traditional approach that is realized by cascading bias thermal correction by calibration and traditional Kalman filtering for bias tracking. This function is very useful when adopted gyros are manufactured using MEMS technology. These systems have significant limitations in terms of sensitivity to environmental conditions. They are characterized by a strong correlation of the systematic error with temperature variations. The traditional process is divided into two separated algorithms, i.e., calibration and filtering, and this aspect reduces system accuracy, reliability, and maintainability. This paper proposes an innovative Zero Velocity Update filter that just requires raw uncalibrated gyro data as input. It unifies in a single algorithm the two steps from the traditional approach. Therefore, it saves time and economic resources, simplifying the management of thermal correction process. In the paper, traditional and innovative Zero Velocity Update filters are described in detail, as well as the experimental data set used to test both methods. The performance of the two filters is compared both in nominal conditions and in the typical case of a residual initial alignment bias. In this last condition, the innovative solution shows significant improvements with respect to the traditional approach. This is the typical case of an aircraft or a car in parking conditions under solar input.

An Innovative Strategy for Accurate Thermal Compensation of Gyro Bias in Inertial Units by Exploiting a Novel Augmented Kalman Filter.

Science.gov (United States)

Fontanella, Rita; Accardo, Domenico; Moriello, Rosario Schiano Lo; Angrisani, Leopoldo; Simone, Domenico De

2018-05-07

This paper presents an innovative model for integrating thermal compensation of gyro bias error into an augmented state Kalman filter. The developed model is applied in the Zero Velocity Update filter for inertial units manufactured by exploiting Micro Electro-Mechanical System (MEMS) gyros. It is used to remove residual bias at startup. It is a more effective alternative to traditional approach that is realized by cascading bias thermal correction by calibration and traditional Kalman filtering for bias tracking. This function is very useful when adopted gyros are manufactured using MEMS technology. These systems have significant limitations in terms of sensitivity to environmental conditions. They are characterized by a strong correlation of the systematic error with temperature variations. The traditional process is divided into two separated algorithms, i.e., calibration and filtering, and this aspect reduces system accuracy, reliability, and maintainability. This paper proposes an innovative Zero Velocity Update filter that just requires raw uncalibrated gyro data as input. It unifies in a single algorithm the two steps from the traditional approach. Therefore, it saves time and economic resources, simplifying the management of thermal correction process. In the paper, traditional and innovative Zero Velocity Update filters are described in detail, as well as the experimental data set used to test both methods. The performance of the two filters is compared both in nominal conditions and in the typical case of a residual initial alignment bias. In this last condition, the innovative solution shows significant improvements with respect to the traditional approach. This is the typical case of an aircraft or a car in parking conditions under solar input.

FLOWING BILATERAL FILTER: DEFINITION AND IMPLEMENTATIONS

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Maxime Moreaud

2015-06-01

Full Text Available The bilateral filter plays a key role in image processing applications due to its intuitive parameterization and its high quality filter result, smoothing homogeneous regions while preserving the edges of the objects. Considering the image as a topological relief, seeing pixel intensities as peaks and valleys, we introduce a way to control the tonal weighting coefficients, the flowing bilateral filter, reducing "halo" artifacts typically produced by the regular bilateral filter around a large peak surrounded by two valleys of lower values. In this paper we propose to investigate exact and approximated versions of CPU and parallel GPU (Graphical Processing Unit based implementations of the regular and flowing bilateral filter using the NVidia CUDA API. Fast implementations of these filters are important for the processing of large 3D volumes up to several GB acquired by x-ray or electron tomography.

Precise and versatile formula for birefringent filters

Science.gov (United States)

Shao, Zhongxing

1996-07-01

In an investigation of extraordinary-(E-) ray behavior and the index of refraction for E waves in a uniaxial crystal, a precise and versatile formula for birefringent filters, based on the exact construction of the optical path difference, is set up with neither the approximation Delta n = no - ne less than or equals no (or n e), nor the ambiguity sin( theta )/sin(rw) = ne. The exact construction gives the correct variation of the position and the dimension in each path, yielding the path difference while the filter is tuning. The formula is applicable not only to a filter with its optical axis parallel to the entrance surface (FAPS) but also to a filter with its axis inclined to the surface (FAIS). Also, the formula indicates that a FAIS allows laser wavelengths to be tuned over a wider range than does a FAPS. The origin of the wider range is interpreted to be the greater variation in the index for the FAIS while the filter is tuning. With the help of the formula we design a FAIS for tuning a cw 42.25.Lc.

Hygienic safety of reusable tap water filters (Germlyser® with an operating time of 4 or 8 weeks in a haematological oncology transplantation unit

Directory of Open Access Journals (Sweden)

Rochow Markus

2007-05-01

Full Text Available Abstract Background Microbial safe tap water is crucial for the safety of immunosuppressed patients. Methods To evaluate the suitability of new, reusable point-of-use filters (Germlyser®, Aquafree GmbH, Hamburg, Germany, three variations of a reusable filter with the same filter principle but with different outlets (with and without silver and inner surface coating of the filter encasements (with and without nano-crystalline silver were tested. The filter efficacy was monitored over 1, 4 and 8 weeks operating time in a haematological oncology transplantation unit equipped with 18 water outlets (12 taps, 6 showers. Results The filtered water fulfilled the requirements of absence of pathogens over time. From 348 samples, 8 samples (2.3% exceeded 100 cfu/ml (no sample ≥ 500 cfu/ml. As no reprocessed filter exhibited 100% filter efficacy in the final quality control after each reprocessing, these contaminations could be explained by retrograde contamination during use. Conclusion As a consequence of the study, the manufacturer recommends changing filters after 4 weeks in high risk areas and after 8 weeks in moderate infectious risk areas, together with routine weekly alcohol-based surface disinfection and additionally in case of visible contamination. The filter efficacy of the 3 filters types did not differ significantly regarding total bacterial counts. Manual reprocessing proved to be insufficient. Using a validated reprocessing in a washer/disinfector with alkaline, acid treatment and thermic disinfection, the filters were effectively reprocessable and now provide tap water meeting the German drinking water regulations as well as the WHO guidelines, including absence of pathogens.

Testing Of The Dual Rotary Filter System

International Nuclear Information System (INIS)

Herman, D.; Fowley, M.; Stefanko, D.

2011-01-01

The Savannah River National Laboratory (SRNL) installed and tested two hydraulically connected SpinTek rotary microfilter (RMF) units to determine the behavior of a multiple filter system. Both units were successfully controlled by a control scheme written in DELTA-V architecture by Savannah River Remediation (SRR) Process Control Engineering personnel. The control system was tuned to provide satisfactory response to changing conditions during the operation of the multi-filter system. Stability was maintained through the startup and shutdown of one of the filter units while the second was still in operation. The installation configuration originally proposed by the Small Colum Ion Exchange (SCIX) project of independent filter and motor mountings may be susceptible to vibration. Significant stiffening of the filter and motor mounts was required to minimize the vibration. Alignment of the motor to the filter was a challenge in this test configuration. The deployment configuration must be easy to manipulate and allow for fine adjustment. An analysis of the vibration signature of the test system identified critical speeds. Whether it corresponds to the resonance frequency of a rotor radial vibration mode that was excited by rotor unbalance is uncertain based upon the measurements. A relative motion series should be completed on the filter with the final shaft configuration to determine if the resonances exist in the final filter design. The instrumentation selected for deployment, including the concentrate discharge control valve and flow meters, performed well. Automation of the valve control integrated well with the control scheme and when used in concert with the other control variables, allowed automated control of the dual RMF system. The one area of concern with the instrumentation was the condition resulting when the filtrate flow meter operated with less than three gpm. This low flow was at the lower range of performance for the flow meter. This should not be

TESTING OF THE DUAL ROTARY FILTER SYSTEM

Energy Technology Data Exchange (ETDEWEB)

Herman, D.; Fowley, M.; Stefanko, D.

2011-08-29

The Savannah River National Laboratory (SRNL) installed and tested two hydraulically connected SpinTek rotary microfilter (RMF) units to determine the behavior of a multiple filter system. Both units were successfully controlled by a control scheme written in DELTA-V architecture by Savannah River Remediation (SRR) Process Control Engineering personnel. The control system was tuned to provide satisfactory response to changing conditions during the operation of the multi-filter system. Stability was maintained through the startup and shutdown of one of the filter units while the second was still in operation. The installation configuration originally proposed by the Small Colum Ion Exchange (SCIX) project of independent filter and motor mountings may be susceptible to vibration. Significant stiffening of the filter and motor mounts was required to minimize the vibration. Alignment of the motor to the filter was a challenge in this test configuration. The deployment configuration must be easy to manipulate and allow for fine adjustment. An analysis of the vibration signature of the test system identified critical speeds. Whether it corresponds to the resonance frequency of a rotor radial vibration mode that was excited by rotor unbalance is uncertain based upon the measurements. A relative motion series should be completed on the filter with the final shaft configuration to determine if the resonances exist in the final filter design. The instrumentation selected for deployment, including the concentrate discharge control valve and flow meters, performed well. Automation of the valve control integrated well with the control scheme and when used in concert with the other control variables, allowed automated control of the dual RMF system. The one area of concern with the instrumentation was the condition resulting when the filtrate flow meter operated with less than three gpm. This low flow was at the lower range of performance for the flow meter. This should not be

Physical characteristics of the paper filter and low cafestol content filter coffee brews.

Science.gov (United States)

Rendón, Mery Yovana; Dos Santos Scholz, Maria Brígida; Bragagnolo, Neura

2018-06-01

The results found in the literature concerning the effect of consuming filter coffee brews on increasing the blood cholesterol levels due to the presence of diterpenes, are divergent. Thus the present research evaluated the diterpene (cafestol and kahweol) concentrations in filter coffee brews prepared with paper filters of different sizes, colors and origins (Brazil, Japan, The United States of America, Germany, France and the Netherlands), with and without micro perforations. This is the first study that reports the physical characteristics of paper filter and its importance to obtain filter coffee brew with low cafestol content. Thus, a sample of Catuai cultivar coffee with high cafestol content was roasted to a medium-light degree and used to prepare the brews in a 1:10 ratio (coffee powder to water). The diterpenes were extracted by direct saponification and quantified and identified by HPLC-DAD-MS/MS. The paper filters were physically characterized by measuring their grammage, and the fat permeation rate calculated in order to better understand the differences between the filters which allow one to obtain higher or lower diterpene contents. The cafestol and kahweol concentrations in the brews varied from 1.62 to 2.98 mg/L and from 0.73 to 1.96 mg/L, respectively. The highest cafestol and kahweol concentrations were obtained using paper filters with micro perforations, considering similar sized paper filters. The paper filters showed high fat permeability and grammages between 50.46 and 67.48 g/m 2 . The diterpene retention capacities of the filters produced in the different countries were similar. The results showed that the porosity of the paper filter and the particle size of the ground roasted coffee were determinant factors in obtaining filter coffee brews with lower cafestol contents. Copyright © 2018 Elsevier Ltd. All rights reserved.

Neutron transmission through pyrolytic graphite crystals

Energy Technology Data Exchange (ETDEWEB)

Adib, M. [Reactor Physics Department NRC, Reactor Physics Division, Nuclear Research Center, Egyptian Atomic Energy Authority, Cairo 13759 (Egypt); Habib, N. [Reactor Physics Department NRC, Reactor Physics Division, Nuclear Research Center, Egyptian Atomic Energy Authority, Cairo 13759 (Egypt)]. E-mail: nadiahabib15@yahoo.com; Fathaalla, M. [Reactor Physics Department NRC, Reactor Physics Division, Nuclear Research Center, Egyptian Atomic Energy Authority, Cairo 13759 (Egypt)

2006-05-15

Calculation of the total cross-section, neutron transmission and removal coefficient of pyrolytic graphite (PG) for thermal neutron energies were carried out using an additive formula. The formula takes into account the variation of thermal diffuse and Bragg scattering cross-sections in terms of PG temperature and mosaic spread for neutron energies in the range 1 meV to 1 eV. A computer code PG has been developed which allow calculations for the graphite in its hexagonal close-packed structure, when its c-direction is parallel with incident neutron beam (parallel orientation). The calculated total neutron cross-sections for PG in parallel orientation at different mosaic spreads were compared with the measured values. An overall agreement is indicated between the formula fits and experimental data at room and liquid nitrogen temperatures. A feasibility study for use of PG crystals as second-order neutron filter is detailed in terms of mosaic spread, optimum thickness and temperature. The calculated removal coefficients of PG crystals show that such crystals are high efficiency second-order filter within neutron energy intervals (4-7 meV) and (10-15 meV)

Spin filtering through ferromagnetic BiMn O3 tunnel barriers

Science.gov (United States)

Gajek, M.; Bibes, M.; Barthélémy, A.; Bouzehouane, K.; Fusil, S.; Varela, M.; Fontcuberta, J.; Fert, A.

2005-07-01

We report on experiments of spin filtering through ultrathin single-crystal layers of the insulating and ferromagnetic oxide BiMnO3 (BMO). The spin polarization of the electrons tunneling from a gold electrode through BMO is analyzed with a counterelectrode of the half-metallic oxide La2/3Sr1/3MnO3 (LSMO). At 3K we find a 50% change of the tunnel resistances according to whether the magnetizations of BMO and LSMO are parallel or opposite. This effect corresponds to a spin-filtering efficiency of up to 22%. Our results thus show the potential of complex ferromagnetic insulating oxides for spin filtering and injection.

Protein-crystal growth experiment (planned)

Science.gov (United States)

Fujita, S.; Asano, K.; Hashitani, T.; Kitakohji, T.; Nemoto, H.; Kitamura, S.

1988-01-01

To evaluate the effectiveness of a microgravity environment on protein crystal growth, a system was developed using 5 cubic feet Get Away Special payload canister. In the experiment, protein (myoglobin) will be simultaneously crystallized from an aqueous solution in 16 crystallization units using three types of crystallization methods, i.e., batch, vapor diffusion, and free interface diffusion. Each unit has two compartments: one for the protein solution and the other for the ammonium sulfate solution. Compartments are separated by thick acrylic or thin stainless steel plates. Crystallization will be started by sliding out the plates, then will be periodically recorded up to 120 hours by a still camera. The temperature will be passively controlled by a phase transition thermal storage component and recorded in IC memory throughout the experiment. Microgravity environment can then be evaluated for protein crystal growth by comparing crystallization in space with that on Earth.

Rotation speed measurement for turbine governor: torsion filtering by using Kalman filter

International Nuclear Information System (INIS)

Houry, M.P.; Bourles, H.

1996-01-01

The rotation speed of a turbogenerator is disturbed by its shaft torsion. Obtaining a filtered measure of this speed is a problem of a great practical importance for turbine governor. A good filtering of this speed must meet two requirements: it must cut frequencies of the shaft torsion oscillation and it must not reduce or delay the signal in the pass-band, i.e. at lower frequencies. At Electricite de France, the speed measure is used to set in motion the fast valving system as quickly as possible, after a short circuit close to the unit or rather an islanding. It is difficult to satisfy these two requirements by using conventional filtering methods. The standard solution consists in a first order filter: at Electricite de France, its time constant is equal to 80 ms. We have decided to improve this filtering by designing a new filter which cuts the frequencies of the shaft torsion oscillation without reducing the bandwidth to the speed measure. If one uses conventional methods to obtain a band stop filter, it is easy to obtain the desired magnitude but not a phase near zero in the whole pass-band. Therefore, we have chosen to design the filter by using Kalman'a theory. The measurement noise is modeled as a colored one, generated by a very lightly damped system driven by a while noise. The resulting Kalman filter is an effective band stop filter, whose phase nicely remains near zero in the whole pass-band. The digital simulations we made and the tests we carried out with the Electricite de France Micro Network laboratory show the advantages of the rotation speed filter we designed using Kalman's theory. With the proposed filter, the speed measure filtering is better in terms of reduction and phase shift. the result is that there are less untimely solicitations of the fast valving system. Consequently, this device improves the power systems stability by minimizing the risks of deep perturbations due to a temporary lack of generation and the risks of under-speed loss

Dust collected in air filters - Possible source of volatile organic compounds and particles; Ger smutsiga luftfilter foersaemrad tilluft ? En studie av emissioner med ursprung i filter

Energy Technology Data Exchange (ETDEWEB)

Johansson, J.H.P.; Rosell, Lars

1998-06-01

Emissions from dust collected in air filters have been investigated using in situ measurements. Two air filters of different classes (F6 and F8/9) have been exposed to outdoor air for a preconditioning period of six months. After this period measurements have been carried out using two operating conditions, continuous and intermittent. Air samples were taken both up- and downstream of the filters. The air samples were analysed regarding volatile organic compounds (VOCs), including formaldehyde and microbial VOCs (mVOC) and the samples of airborne dust were examined regarding the contents of colony forming units, ergosterol (marker of fungi), and endotoxin (marker of gram negative bacteria). Furthermore, a visual inspection of the airborne dust was conducted using SEM. Particles released when the fan was turned on and a short period after, were monitored using an optical particle counter, slitsamplers (fungus spores) and membrane filters for SEM analysis. After finishing the in situ measurements, the filters were placed in climate chambers for emission sampling. Finally, samples were cut out for analysis of microbial contents in the filter material, both on the dusty and `clean` side of the filters. No consistent change of VOC, aldehyde or mVOC concentrations across the filters could be measured. A significant ozone reduction was seen in one of the in situ measurements. The chamber experiments showed that the filters were a source of various VOCs, e.g. aldehydes and mVOCs. The emission of mVOCs in the chambers was significantly higher for the F8/9 filter, probably due to more and finer dust in that filter. Only a few colonization units (fungi) penetrate filters when running continuously but an increase was noted at the moment the fans were started. The same phenomenon was observed with the optical particle counter, but both the intensity and length of the increase, for colonization units and other particles, were moderate. Mycological examination of the filter

Iron turbidity removal from the active process water system of the Kaiga Generating Station Unit 1 using an electrochemical filter

International Nuclear Information System (INIS)

Venkateswaran, G.; Gokhale, B.K.

2007-01-01

Iron turbidity is observed in the intermediate cooling circuit of the active process water system (APWS) of Kaiga Generating Station (KGS). Deposition of hydrous/hydrated oxides of iron on the plate type heat exchanger, which is employed to transfer heat from the APWS to the active process cooling water system (APCWS), can in turn result in higher moderator D 2 O temperatures due to reduced heat transfer. Characterization of turbidity showed that the major component is γ-FeOOH. An in-house designed and fabricated electrochemical filter (ECF) containing an alternate array of 33 pairs of cathode and anode graphite felts was successfully tested for the removal of iron turbidity from the APWS of Kaiga Generating Station Unit No. 1 (KGS No. 1). A total volume of 52.5 m 3 water was processed using the filter. At an average inlet turbidity of 5.6 nephelometric turbidity units (NTU), the outlet turbidity observed from the ECF was 1.6 NTU. A maximum flow rate (10 L . min -1 ) and applied potential of 18.0-20.0 V was found to yield an average turbidity-removal efficiency of ∝ 75 %. When the experiment was terminated, a throughput of > 2.08 . 10 5 NTU-liters was realized without any reduction in the removal efficiency. Removal of the internals of the filter showed that only the bottom 11 pairs of felts had brownish deposits, while the remaining felts looked clean and unused. (orig.)

Correction of Bowtie-Filter Normalization and Crescent Artifacts for a Clinical CBCT System.

Science.gov (United States)

Zhang, Hong; Kong, Vic; Huang, Ke; Jin, Jian-Yue

2017-02-01

To present our experiences in understanding and minimizing bowtie-filter crescent artifacts and bowtie-filter normalization artifacts in a clinical cone beam computed tomography system. Bowtie-filter position and profile variations during gantry rotation were studied. Two previously proposed strategies (A and B) were applied to the clinical cone beam computed tomography system to correct bowtie-filter crescent artifacts. Physical calibration and analytical approaches were used to minimize the norm phantom misalignment and to correct for bowtie-filter normalization artifacts. A combined procedure to reduce bowtie-filter crescent artifacts and bowtie-filter normalization artifacts was proposed and tested on a norm phantom, CatPhan, and a patient and evaluated using standard deviation of Hounsfield unit along a sampling line. The bowtie-filter exhibited not only a translational shift but also an amplitude variation in its projection profile during gantry rotation. Strategy B was better than strategy A slightly in minimizing bowtie-filter crescent artifacts, possibly because it corrected the amplitude variation, suggesting that the amplitude variation plays a role in bowtie-filter crescent artifacts. The physical calibration largely reduced the misalignment-induced bowtie-filter normalization artifacts, and the analytical approach further reduced bowtie-filter normalization artifacts. The combined procedure minimized both bowtie-filter crescent artifacts and bowtie-filter normalization artifacts, with Hounsfield unit standard deviation being 63.2, 45.0, 35.0, and 18.8 Hounsfield unit for the best correction approaches of none, bowtie-filter crescent artifacts, bowtie-filter normalization artifacts, and bowtie-filter normalization artifacts + bowtie-filter crescent artifacts, respectively. The combined procedure also demonstrated reduction of bowtie-filter crescent artifacts and bowtie-filter normalization artifacts in a CatPhan and a patient. We have developed a step

Rotating Ceramic Water Filter Discs System for Water Filtration

Directory of Open Access Journals (Sweden)

Riyadh Z. Al Zubaidy

2017-04-01

Full Text Available This work aimed to design, construct and operate a new laboratory scale water filtration system. This system was used to examine the efficiency of two ceramic filter discs as a medium for water filtration. These filters were made from two different ceramic mixtures of local red clay, sawdust, and water. The filtration system was designed with two rotating interfered modules of these filters. Rotating these modules generates shear force between water and the surfaces of filter discs of the filtration modules that works to reduce thickness of layer of rejected materials on the filters surfaces. Each module consists of seven filtration units and each unit consists of two ceramic filter discs. The average measured hydraulic conductivity of the first module was 13.7mm/day and that for the second module was 50mm/day. Results showed that the water filtration system can be operated continuously with a constant flow rate and the filtration process was controlled by a skin thin layer of rejected materials. The ceramic water filters of both filtration modules have high removal efficiency of total suspended solids up to 100% and of turbidity up to 99.94%.

Thermal neutron detectors based on complex oxide crystals

CERN Document Server

Ryzhikov, V; Volkov, V; Chernikov, V; Zelenskaya, O

2002-01-01

The ways of improvement of spectrometric quality of CWO and GSO crystals have been investigated with the aim of their application in thermal neutron detectors based on radiation capture reactions. The efficiency of the neutron detection by these crystals was measured, and the obtained data were compared with the results for sup 6 LiI(Tl) crystals. It is shown that the use of complex oxide crystals and neutron-absorption filters for spectrometry of thermal and resonance neutrons could be a promising method in combination with computer data processing. Numerical calculations are reported for spectra of gamma-quanta due to radiation capture of the neutrons. To compensate for the gamma-background lines, we used a crystal pair of heavy complex oxides with different sensitivity to neutrons.

Utilizations of filtered neutron beams at Dalat nuclear research reactor

International Nuclear Information System (INIS)

Hien, P.D.; Chau, L.N.; Tan, V.H.; Hiep, N.T.; Phuong, L.B.

1992-01-01

Neutron beam utilizations in basic and applied researches have been important activities at the Dalat nuclear reactor. The neutron filters with single crystal of silicon are used to produce thermal neutrons at the tangential horizontal channel and quasi-monoenergetic 144 KeV and 54 KeV neutrons at the piercing beam tube. The paper presents some relevant characteristics of the filtered neutron beams at the two horizontal channels. Applications of neutron beams in prompt gamma-ray activation analysis and in nuclear data measurements are briefly described. (author)

Optimal design of active EMC filters

Science.gov (United States)

Chand, B.; Kut, T.; Dickmann, S.

2013-07-01

A recent trend in automotive industry is adding electrical drive systems to conventional drives. The electrification allows an expansion of energy sources and provides great opportunities for environmental friendly mobility. The electrical powertrain and its components can also cause disturbances which couple into nearby electronic control units and communication cables. Therefore the communication can be degraded or even permanently disrupted. To minimize these interferences, different approaches are possible. One possibility is to use EMC filters. However, the diversity of filters is very large and the determination of an appropriate filter for each application is time-consuming. Therefore, the filter design is determined by using a simulation tool including an effective optimization algorithm. This method leads to improvements in terms of weight, volume and cost.

Systematic Procedure for Generating Operational Policies to Achieve Target Crystal Size Distribution (CSD) in Batch Cooling Crystallization

DEFF Research Database (Denmark)

Abdul Samad, Noor Asma Fazli; Singh, Ravendra; Sin, Gürkan

2011-01-01

Batch cooling crystallization is one of the important unit operations involving separation of solid-liquid phases. Usually the most common crystal product qualities are directly related to the crystal size distribution (CSD). However the main difficulty in batch crystallization is to obtain a uni...

Hemispherical-field-of-view, nonimaging narrow-band spectral filter

Science.gov (United States)

Miles, R. B.; Webb, S. G.; Griffith, E. L.

1981-01-01

Two compound parabolic concentrators are used to create a 180-deg-field-of-view spectral filter. The collection optics are reflective and are designed to collimate the light through a multilayer interference filter and then to refocus it onto an optical detector. Assuming unit reflectance and no loss through the optical filter, this device operates at the thermodynamic collection limit.

Proposing Wavelet-Based Low-Pass Filter and Input Filter to Improve Transient Response of Grid-Connected Photovoltaic Systems

Directory of Open Access Journals (Sweden)

Bijan Rahmani

2016-08-01

Full Text Available Available photovoltaic (PV systems show a prolonged transient response, when integrated into the power grid via active filters. On one hand, the conventional low-pass filter, employed within the integrated PV system, works with a large delay, particularly in the presence of system’s low-order harmonics. On the other hand, the switching of the DC (direct current–DC converters within PV units also prolongs the transient response of an integrated system, injecting harmonics and distortion through the PV-end current. This paper initially develops a wavelet-based low-pass filter to improve the transient response of the interconnected PV systems to grid lines. Further, a damped input filter is proposed within the PV system to address the raised converter’s switching issue. Finally, Matlab/Simulink simulations validate the effectiveness of the proposed wavelet-based low-pass filter and damped input filter within an integrated PV system.

Analysis of Depressurization Performance in Containment of Wolsong NPP Unit 1 through Containment Filtered Venting System

International Nuclear Information System (INIS)

Lee, Sunghan; Kim, Jinhyuck; Suh, Nam Duk; Cho, Songwon

2014-01-01

Containment filtered venting system (CFVS) is designed to open and to close isolation valves passively by an operator. CFVS is operated when the containment pressure exceeds the design pressure (225 kPa(a)) and is closed when the containment pressure decreases below 151 kPa(a). The aim of this study is to analyze the depressurization performance of Wolsong unit 1 through CFVS during SBO. The thermal-hydraulic behavior in containment of Wolsong unit 1 was evaluated using the MELCOR 1.8.6 code developed at Sandia National Laboratories (SNL) for the U.S. Nuclear Regulatory Commission (NRC). In addition, in order to evaluate the effects of the CFVS according to the venting area, a sensitivity study depending on different venting area of the CFVS was conducted. Finally, an analysis of the effects of filtering and scrubbing of radioactive material for CFVS is important but not treated in this paper. The SBO accident is chosen to analyze the thermal-hydraulic behavior of Wolsong unit 1. During SBO, the analysis of CFVS affecting on the depressurization of the containment was conducted using MELCOR 1.8.6 code. Also, a sensitivity study was carried out to evaluate the depressurization performance according to the venting area of CFVS. The results show that the containment pressure is considerably decreased and the integrity of the containment could be maintained in case of CFVS operating. Therefore, CFVS has the capacity to keep the containment pressure below the design pressure during SBO. In addition, there are large differences in the containment pressure depending on venting area. We found that the decreasing rate of the pressure in the containment and water level in CFVS depends on the venting area. In the future, a proper requirement for CFVS sizing criteria according to accident scenarios such as LBLOCA, SBLOCA and SGTR, etc. should be evaluated in order to review the licensing for CFVS. Finally, analyses of aerosols, fission product, and radioactive material

All-in-fibre Rayleigh-rejection filter for raman spectroscopy

DEFF Research Database (Denmark)

Brunetti, Anna Chiara; Scolari, L.; Lund-Hansen, T.

2012-01-01

An in-line Rayleigh-rejection filter for Raman spectroscopy is demonstrated. The device is based on a solid-core photonic crystal fibre infiltrated with a high-index liquid. At room temperature, the filter exhibits a full width at half maximum bandwidth of 143 nm and an insertion loss of 0.3 d......B. A shift of 32 nm of the central wavelength is demonstrated by increasing the temperature from 22 to 70°C. FEM simulations of the spectra at different temperatures showed good agreement with experimental results. The device was successfully employed to perform Raman spectroscopy of a sample of cyclohexane...

Particle tracking from image sequences of complex plasma crystals

International Nuclear Information System (INIS)

Hadziavdic, Vedad; Melandsoe, Frank; Hanssen, Alfred

2006-01-01

In order to gather information about the physics of the complex plasma crystals from the experimental data, particles have to be tracked through a sequence of images. An application of the Kalman filter for that purpose is presented, using a one-dimensional approximation of the particle dynamics as a model for the filter. It is shown that Kalman filter is capable of tracking dust particles even with high levels of measurement noise. An inherent part of the Kalman filter, the innovation process, can be used to estimate values of the physical system parameters from the experimental data. The method is shown to be able to estimate the characteristic oscillation frequency from noisy data

Projects on filter testing in Sweden

International Nuclear Information System (INIS)

Normann, B.; Wiktorsson, C.

1985-01-01

The Swedish nuclear power program comprises twelve light water reactors. Nine are boiling water reactors of ASEA-ATOM design and three are pressurized water reactors of Westinghouse design. Of these, ten are in operation and two are under construction and planned to go into operation during late 1984 and early 1985, respectively. Frequent tests on the penetration of particles through HEPA filters, regular tests on the adsorption of methyl iodide in the stand-by carbon filter units by laboratory testing are discussed. The proposed new regulations are based on many years of experience of filter system operation and of tests in-situ and in the laboratory. Moisture and water are factors that affect the functioning of filters. In addition, high loading of dust can give rise to increased penetration through HEPA filters, however pinholes could have less influence on the total penetration. Laboratory tests show that DOP particles retain 30-40% in 90 mm carbon filters (8-12 mesh). However no effect on the ability of carbon to adsorb methyl iodide after DOP contamination in combined carbon/HEPA filters has been observed. Leakage from ventilation ducts can cause radioactive contamination problems during filter testing with radioiodine. In-situ testing of control-room filters has been performed using inactive methyl iodide. A type of carbon bed not previously used in Sweden has been introduced. Testing of this filter type is discussed

Physichal parameters for wedge filters used in radiotherapy

International Nuclear Information System (INIS)

Strunga, Emil

1995-01-01

Wedge filters using in radiotherapy up two important problems: attenuation of gamma rays introduced by the presence of wedge filters and spinning of isodoses curves plate. Depending of irradiation geometry, characterised by D w , - source filter distance, D c - source dose's estimate point distance, a - side of irradiation field; nature and size filter: α - wedge angle, μ - linear adsorption coefficient, ε - filter cover attenuation w - filter side, and nature of target volume characterised by μ' - linear absorption coefficient of medium has been estimated absorption factor of wedge filter (k w ) for two irradiation geometry: and spinning angle of isodose plate (Θ): 3) tg θ (μD w (μ'D c - 2 Calculated values has been compared with the experimental measured values, for a cobaltotherapy unit Rokus-M, and the result was that between the two series of dates it is a good concordance

Testing of a Rotary Micro-filter for Hanford Applications

International Nuclear Information System (INIS)

Poirier, M.R.; Herman, D.T.; Stefanko, D.B.; Fink, S.D.

2009-01-01

Savannah River National Laboratory (SRNL) researchers are investigating and developing a rotary micro-filter for solid-liquid separation applications with emphasis on deployment in radioactive services. The Department of Energy (DOE) Office of Waste Processing employed the SRNL team to evaluate the use of this rotary micro-filter for the Hanford Supplemental Pretreatment process. The authors tested a full-scale, 25-disk filter unit containing 0.5 μ filter media using a Hanford Tank AN-105 simulant at solids loadings of 0.06, 0.29, and 1.29 wt %. Based on recommendations from prior tests, the authors modified the filter unit by replacing the primary mechanical seal with an air seal. They also replaced the bushing with alternate materials of construction aimed at extended mean time between maintenance events. The testing provides the following conclusions. - The rotary filter produces a higher flux than the crossflow filter for the Hanford simulant. The gain in performance is less than previously seen for Savannah River Site simulants. - Filtrate clarity proved excellent with turbidity of <4 NTU (nephelometric turbidity units) in all samples. - Inspection of the primary mechanical seal faces after ∼140 hours of operation showed an expected minimal amount of initial wear, no passing of process fluid through the seal faces, and very little change in the air channeling grooves on the stationary face. - Some polishing of surfaces occurred at the bottom of the shaft bushing. The authors recommend improving the shaft bushing by holding it in place with a locking ring and incorporating grooves to provide additional cooling. - The authors recommend that Hanford test other pore size media to determine the optimum pore size for Hanford waste. - During final facility operation, the filter should be rinsed with filtrate or dilute caustic and drained prior to an extended shutdown to prevent the formation of a layer of settled solids on top of the filter disks. (authors)

An Application of Filtered Renewal Processes in Hydrology

Directory of Open Access Journals (Sweden)

Mario Lefebvre

2014-01-01

Full Text Available Filtered renewal processes are used to forecast daily river flows. For these processes, contrary to filtered Poisson processes, the time between consecutive events is not necessarily exponentially distributed, which is more realistic. The model is applied to obtain one- and two-day-ahead forecasts of the flows of the Delaware and Hudson Rivers, both located in the United States. Better results are obtained than with filtered Poisson processes, which are often used to model river flows.

Linear filtering applied to Monte Carlo criticality calculations

International Nuclear Information System (INIS)

Morrison, G.W.; Pike, D.H.; Petrie, L.M.

1975-01-01

A significant improvement in the acceleration of the convergence of the eigenvalue computed by Monte Carlo techniques has been developed by applying linear filtering theory to Monte Carlo calculations for multiplying systems. A Kalman filter was applied to a KENO Monte Carlo calculation of an experimental critical system consisting of eight interacting units of fissile material. A comparison of the filter estimate and the Monte Carlo realization was made. The Kalman filter converged in five iterations to 0.9977. After 95 iterations, the average k-eff from the Monte Carlo calculation was 0.9981. This demonstrates that the Kalman filter has the potential of reducing the calculational effort of multiplying systems. Other examples and results are discussed

Structural transitions in crystals of native aspartate carbamoyltransferase

International Nuclear Information System (INIS)

Gouaux, J.E.; Lipscomb, W.N.

1989-01-01

Screened precession x-ray photographs of crystals of native aspartate carbamoyltransferase ligated with L-aspartate and phosphate reveal the presence of a crystal unit-cell dimension that is intermediate between the T (tense) and R (relaxed) states. Characterizing the intermediate (I) crystal is a c-axis unit-cell dimension of 149 angstrom, halfway between the c-axis length of the T (c = 142 angstrom) and R (c = 156 angstrom) states, in the space group P321. Preservation of the P321 space group indicates that the intermediate crystal form retains a threefold axis of symmetry, and therefore the enzyme has at minimum a threefold axis; however, it is not known whether the molecular twofold axis is conserved. The I crystals are formed by soaking T-state crystals with L-aspartate and phosphate. By raising the concentration of L-aspartate the authors can further transform the I crystals, without fragmentation, to a form that has the same unit-cell dimensions as R-state crystals grown in the presence of N-(phosphonoacetyl)-L-aspartate

Far infrared filters for the Galileo-Jupiter and other missions

Science.gov (United States)

Seeley, J. S.; Hunneman, R.; Whatley, A.

1981-01-01

Progress in the development of FIR multilayer interference filters for the net flux radiometer and photopolarizing radiometer to be carried on board the Galileo mission to Jupiter is reported. The multilayer interference technique has been extended to the region above 40 microns by the use of PbTe/II-VI materials in hard-coated combination, with the thickest layers composed of CdSe QWOT at 74 microns and PbTe QWOT. Improvements have also been obtained in filters below 20 microns on the basis of the Chebyshev stack design. A composite filter cutting on steeply at 40 microns has been designed which employs a thin crystal quartz substrate, shorter wavelength absorption in ZnS and As2S3 thin films, and supplementary multilayer interference. Finally, absorptive filters have been developed based on II-VI compounds in multilayer combination with KRS-5 (or 6) on a KRS-5 (or 6) substrate

Filtered containment venting in Sweden

International Nuclear Information System (INIS)

Lindau, L.; Ellisson, K.

1989-01-01

After the TMI accident, Swedish authorities decided that all Swedish nuclear power plants should be upgraded with respect to mitigation of the consequences of severe accidents. One contribution to meet these ends is filtered containment venting, i.e. means to relieve containment overpressure and to clean the relief gas from radioactive components. The first system in operation was built at the Barsebaeck site (2 BWR's) where a gravel bed filter was installed. For the remaining Swedish units (7 BWR's and 3 PWR's) a passive, self-controlling wet scrubber system, FILTRA-MVSS, is now under installation. The principle of the FILTRA-MVSS is a self-controlling, self-pumping venturi collector submerged in a pool, and it is used to filter out emissions of solid and gaseous radioactive components

HEPA filter concerns - an overview

Energy Technology Data Exchange (ETDEWEB)

Leonard, J.F. [Department of Energy, Washington, DC (United States)

1995-02-01

The U.S. Department of Energy (DOE) recently initiated a complete review of the DOE High Efficiency Particulate Air (HEPA) Filter Program to identify areas for improvement. Although this process is currently ongoing, various issues and problems have already been identified for action that not only impacts the DOE HEPA filter program, but potentially the national and international air cleaning community as well. This paper briefly reviews a few of those concerns that may be of interest, and discusses actions initiated by the DOE to address the associated issues and problems. Issues discussed include: guidance standards, in-place testing, specifications, Test Facilities, portable units, vacuum cleaners, substitute aerosols, filter efficiencies, aging/shelf life/service life, fire suppression, handbook, Quality Products List (QPL), QA testing, and evaluations.

Metrics for comparing plasma mass filters

Energy Technology Data Exchange (ETDEWEB)

Fetterman, Abraham J.; Fisch, Nathaniel J. [Department of Astrophysical Sciences, Princeton University, Princeton, New Jersey 08540 (United States)

2011-10-15

High-throughput mass separation of nuclear waste may be useful for optimal storage, disposal, or environmental remediation. The most dangerous part of nuclear waste is the fission product, which produces most of the heat and medium-term radiation. Plasmas are well-suited to separating nuclear waste because they can separate many different species in a single step. A number of plasma devices have been designed for such mass separation, but there has been no standardized comparison between these devices. We define a standard metric, the separative power per unit volume, and derive it for three different plasma mass filters: the plasma centrifuge, Ohkawa filter, and the magnetic centrifugal mass filter.

Metrics for comparing plasma mass filters

International Nuclear Information System (INIS)

Fetterman, Abraham J.; Fisch, Nathaniel J.

2011-01-01

High-throughput mass separation of nuclear waste may be useful for optimal storage, disposal, or environmental remediation. The most dangerous part of nuclear waste is the fission product, which produces most of the heat and medium-term radiation. Plasmas are well-suited to separating nuclear waste because they can separate many different species in a single step. A number of plasma devices have been designed for such mass separation, but there has been no standardized comparison between these devices. We define a standard metric, the separative power per unit volume, and derive it for three different plasma mass filters: the plasma centrifuge, Ohkawa filter, and the magnetic centrifugal mass filter.

Flattening filter free beams from TrueBeam and Versa HD units: Evaluation of the parameters for quality assurance

Energy Technology Data Exchange (ETDEWEB)

Fogliata, Antonella, E-mail: antonella.fogliata@humanitas.it; Reggiori, Giacomo; Stravato, Antonella; Scorsetti, Marta; Cozzi, Luca [Radiotherapy and Radiosurgery Department, Humanitas Research Hospital, Milan-Rozzano I-20098 (Italy); Fleckenstein, Jens; Schneider, Frank; Lohr, Frank [Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Mannheim D-68167 (Germany); Pachoud, Marc; Ghandour, Sarah [Radiation Oncology Department, Hôpital Riviera Chablais, Vevey CH-1800 (Switzerland); Krauss, Harald [Radio-Oncology Department, Kaiser Franz Josef Spital, Vienna A-1100 (Austria)

2016-01-15

Purpose: Flattening filter free (FFF) beams generated by medical linear accelerators are today clinically used for stereotactical and non-stereotactical radiotherapy treatments. Such beams differ from the standard flattened beams (FF) in the high dose rate and the profile shape peaked on the beam central axis. Definition of new parameters as unflatness and slope for FFF beams has been proposed based on a renormalization factor for FFF profiles. The present study aims to assess the dosimetric differences between FFF beams generated by linear accelerators from different vendors, and to provide renormalization and parameter data of the two kinds of units. Methods: Dosimetric data from two Varian TrueBeam and two Elekta Versa HD linear accelerators, all with 6 and 10 MV nominal accelerating potentials, FF and FFF modes have been collected. Renormalization factors and related fit parameters according to Fogliata et al. [“Definition of parameters for quality assurance of flattening filter free (FFF) photon beams in radiation therapy,” Med. Phys. 39, 6455–6464 (2012)] have been evaluated for FFF beams of both units and energies. Unflatness and slope parameters from profile curves were evaluated. Dosimetric differences in terms of beam penetration and near-the-surface dose were also assessed. Results: FFF profile parameters have been updated; renormalization factors and unflatness from the Varian units are consistent with the published data. Elekta FFF beam qualities, different from the Varian generated beams, tend to express similar behaviour as the FF beam of the corresponding nominal energy. TPR{sub 20,10} for 6 and 10 MV FF and FFF TrueBeam beams are 0.665, 0.629 (6 MV) and 0.738, 0.703 (10 MV). The same figures for Versa HD units are 0.684, 0.678 (6 MV) and 0.734, 0.721 (10 MV). Conclusions: Renormalization factor and unflatness parameters evaluated from Varian and Elekta FFF beams are provided, in particular renormalization factors table and fit parameters.

Filters for radioactive liquid wastes

International Nuclear Information System (INIS)

Koshiba, Yukihiko; Kawashima, Akio

1980-01-01

In the crud generated in the reactor cooling water for nuclear power plants, iron oxides (hematite and magnetite) are contained as the main components, and also Co, Mn, Fe, Cr exist as radioactive nuclides. A new filter to separate these cruds, nuclepore membrane filter (NPMF), was investigated for its adaptability, and has been adopted as a practical filter for radioactive liquid wastes. The NPMF has such features as the possibility of complete automation of operation, no generation of secondary wastes, and easy maintenance, because the NPMF has uniform circular holes in poly-carbonate thin films, and shows the properties of stable filtering of particulates, capability of back washing, and others. The elements mounted in a practical system have such construction that the membrane is cut in the form of doughnut, and sandwiched with 100 mesh polyester nets (spacer); the obtained unit filter (cassette) is mounted on the stackable plate of the same size; and 80 pieces of this cassette are formed in a filter of 4 m 2 filtering area. The performance varies with the properties of suspended matters and the turbidity of wastes. For example, the filtered liquid of 0.1 ppm or less can be obtained when the 1 μm filter material is used to treat the liquid waste containing 1 to 100 ppm suspended matters. Usually back washed water is produced by about 1/100 of treated liquid wastes. The lifetime of the membrane is expected to be 1 or 2 years if crud is the main component. (Wakatsuki, Y.)

Photonic crystal nanostructures for optical biosensing applications

DEFF Research Database (Denmark)

Dorfner, D.; Zabel, T.; Hürlimann, T.

2009-01-01

We present the design, fabrication and optical investigation of photonic crystal (PhC) nanocavity drop filters for use as optical biosensors. The resonant cavity mode wavelength and Q-factor are studied as a function of the ambient refractive index and as a function of adsorbed proteins (bovine...

Development of filtered containment venting system and application for Kashiwazaki-Kariwa Nuclear Power Station Unit 6, 7

International Nuclear Information System (INIS)

Murai, Soutarou; Hiranuma, Naoki; Kimura, Takeo; Omori, Shuichi; Watanabe, Fumitoshi; Sasa, Daisuke

2014-01-01

The Fukushima Dai-ichi Nuclear Power Station (1F) of Tokyo Electric Power Company (TEPCO) had experienced severe radio-active release to the environment in the Tohoku Region Pacific Coast Earthquake (alias: the Great East Japan Earthquake) in 2011. Under the Station Black-Out (SBO) conditions caused by tsunami with the earthquake, the 1F operators had tried to vent the gasses in the Primary Containment Vessels (PCVs) of the unit 1, 2 and 3 to the environment through the water pools in the suppression chambers of the PCVs. Its venting, however, was imperfect and, as a result, major direct radio-active release to the environment was caused. After this disaster, TEPCO launched a project to develop the Filtered Containment Venting System (FCVS), in which our very bitter experiences in the 1F accident as described above are reflected. One of the main purposes of the development of the FCVS is to enhance operability of venting under the severe plant conditions such as the SBO during progressing of severe core damage, and another is to enhance removal performance of radio-nuclides with the newly added filtering equipment, which is installed in the venting line from the PCV to the outer. The Kashiwazaki-Kariwa NPS unit 6 and 7 will be the first reactors applied the FCVSs. In this paper, we show the design concept of the TEPCO's FCVS, the brief overview of the system design and the summary of experiment which has been performed for getting the performance data of the FCVS such as decontamination factor in various conditions. (author)

Reflectivity and filtering characteristics of pyrolytic graphite

International Nuclear Information System (INIS)

Adib, M.; Abdel-Kawy, A.; Ashry, A.; Abbas, Y.; Wahba, W.

1988-01-01

The neutron transmission measurements through oriented pyrolytic graphite (P.G. crystal) were carried out in the wavelength band from 0.15 nm to 6.5 nm at different orientations of the (002) plane of the crystal w.r.t. the neutron beam direction. It was found that the P.G. crystal may be tuned for optimum scattering of second-order neutrons in the wavelength ranging between 0.112 nm and 0.425 nm, by adjusting the filter in an appropriate orientation. The reflectivity of (002), (004) and (006) planes of P.G. were measured and the following results are obtained: the reflectivity of (002) plane was found to be 99% by (transmission method). The ratio of the integrated intensity of the reflected neutrons from (004) and (006) is 3.14+-0.25 and is found to be in agreement with the calculated ratio. The measurements were performed using the fixed scattering angle spectrometer installed in front of the ET-RR-1 reactor horizontal channel

Interim report on the TMI-2 purification filter examination

International Nuclear Information System (INIS)

Mason, R.E.; Hobbins, R.R.; Cook, B.A.; MacDonald, P.E.

1983-02-01

Filters from the purification/makeup system of the Three Mile Island Unit 2 Reactor were examined after the March 28, 1979, accident to determine the character of the debris transported to the filters. The general condition of the filters is presented. Material was removed from the filters and examined. The elemental and radionuclide makeup of the debris is discussed. Distribution of particle size and shape is presentd for some of the material examined. This is an interim report. When the investigation is completed, another report summarizing all of the data will be issued

Impact of axial velocity and transmembrane pressure (TMP) on ARP filter performance

Energy Technology Data Exchange (ETDEWEB)

Poirier, M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Burket, P. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2016-02-29

The Savannah River Site (SRS) is currently treating radioactive liquid waste with the Actinide Removal Process (ARP) and the Modular Caustic Side Solvent Extraction Unit (MCU). Recently, the low filter flux through the ARP of approximately 5 gallons per minute has limited the rate at which radioactive liquid waste can be treated. Salt Batch 6 had a lower processing rate and required frequent filter cleaning. Savannah River Remediation (SRR) has a desire to understand the causes of the low filter flux and to increase ARP/MCU throughput. One potential method for increasing filter flux is to adjust the axial velocity and transmembrane pressure (TMP). SRR requested SRNL to conduct bench-scale filter tests to evaluate the effects of axial velocity and transmembrane pressure on crossflow filter flux. The objective of the testing was to determine whether increasing the axial velocity at the ARP could produce a significant increase in filter flux. The authors conducted the tests by preparing slurries containing 6.6 M sodium Salt Batch 6 supernate and 2.5 g MST/L, processing the slurry through a bench-scale crossflow filter unit at varying axial velocity and TMP, and measuring filter flux as a function of time.

Imaging transport phenomena during lysozyme protein crystal growth by the hanging drop technique

Science.gov (United States)

Sethia Gupta, Anamika; Gupta, Rajive; Panigrahi, P. K.; Muralidhar, K.

2013-06-01

The present study reports the transport process that occurs during the growth of lysozyme protein crystals by the hanging drop technique. A rainbow schlieren technique has been employed for imaging changes in salt concentration. A one dimensional color filter is used to record the deflection of the light beam. An optical microscope and an X-ray crystallography unit are used to characterize the size, tetragonal shape and Bravais lattice constants of the grown crystals. A parametric study on the effect of drop composition, drop size, reservoir height and number of drops on the crystal size and quality is reported. Changes in refractive index are not large enough to create a meaningful schlieren image in the air gap between the drop and the reservoir. However, condensation of fresh water over the reservoir solution creates large changes in the concentration of NaCl, giving rise to clear color patterns in the schlieren images. These have been analyzed to obtain salt concentration profiles near the free surface of the reservoir solution as a function of time. The diffusion of fresh water into the reservoir solution at the early stages of crystal growth followed by the mass flux of salt from the bulk solution towards the free surface has been recorded. The overall crystal growth process can be classified into two regimes, as demarcated by the changes in slope of salt concentration within the reservoir. The salt concentration in the reservoir equilibrates at long times when the crystallization process is complete. Thus, transport processes in the reservoir emerge as the route to monitor protein crystal growth in the hanging drop configuration. Results show that crystal growth rate is faster for a higher lysozyme concentration, smaller drops, and larger reservoir heights.

Flood protection of Crystal River Unit 3 Nuclear Plant

International Nuclear Information System (INIS)

Noble, R.M.; Simpson, B.

1975-01-01

To satisfy U.S. Atomic Energy Commission (AEC) safety criteria, a required evaluation of the worst site-related flood is performed for the Crystal River Plant, located on the Gulf Coast of Florida, the probable maximum stillwater flood levels are likely to be a result of the probable maximum hurricane. Flood protection requirements for the Crystal River Plant are determined by considering the most severe combination of probable maximum hurricane parameters for the Gulf Coast Region. These parameters are used as input to a model of hurricane surge generation and attendant wave activity in order to determine the maximum flood levels at the Crystal River Plant. 4 refs

Report of minutes of government-industry meeting on filters, media, and media testing

International Nuclear Information System (INIS)

Anderson, W.L.

1981-01-01

This session, following the precedents of earlier meetings, related the operating requirements placed on the high efficiency filter and the capacity of industry to meet them. To this end, the collected talents of the assembled body were unified toward the problems of the particulate filter, its components, and its methods of test. The following seven subjects were discussed: round robin paper test program; DOP (di-octyl phthalate) carcinogenicity; DOP substitute (thermal); DOP substitute (air); filter materials in corrosive environments; fire retardant filter frames; and filter unit leakage. Highlights of the session are: results of the round robin filter exchange test program to ascertain the accuracy and reproducibility of the Q127 filter media tester indicated that the overall agreement between the widely dispersed instruments were much better than expected and previously determined; the National Cancer Institute (NCI) is expected to issue in the near future an intelligence bulletin, pointing out that some carcinogenic effect was noted of DOP from bioassay data; it was recommended that polyethylene glycol 400 be accepted as a substitute for DOP in thermal generators; for the Laskin-type air-operated generators, dioctyl sebacate appeared to give the most promising results; a strong recommendation was made that all polyurethane foams be excluded from specifications and use where the filter unit will be exposed to acid environments; filter unit leakage was attributed to a lack of or insufficient adhasive and/or improper application of adhesie

GPU Accelerated Vector Median Filter

Science.gov (United States)

Aras, Rifat; Shen, Yuzhong

2011-01-01

Noise reduction is an important step for most image processing tasks. For three channel color images, a widely used technique is vector median filter in which color values of pixels are treated as 3-component vectors. Vector median filters are computationally expensive; for a window size of n x n, each of the n(sup 2) vectors has to be compared with other n(sup 2) - 1 vectors in distances. General purpose computation on graphics processing units (GPUs) is the paradigm of utilizing high-performance many-core GPU architectures for computation tasks that are normally handled by CPUs. In this work. NVIDIA's Compute Unified Device Architecture (CUDA) paradigm is used to accelerate vector median filtering. which has to the best of our knowledge never been done before. The performance of GPU accelerated vector median filter is compared to that of the CPU and MPI-based versions for different image and window sizes, Initial findings of the study showed 100x improvement of performance of vector median filter implementation on GPUs over CPU implementations and further speed-up is expected after more extensive optimizations of the GPU algorithm .

Filter-adsorber aging assessment

Energy Technology Data Exchange (ETDEWEB)

Winegardner, W.K. [Pacific Northwest Laboratory, Richland, WA (United States)

1995-02-01

An aging assessment of high-efficiency particulate (HEPA) air filters and activated carbon gas adsorption units was performed by the Pacific Northwest Laboratory as part of the U.S. Nuclear Regulatory Commission`s (USNRC) Nuclear Plant Aging Research (NPAR) Program. This evaluation of the general process in which characteristics of these two components gradually change with time or use included the compilation of information concerning failure experience, stressors, aging mechanisms and effects, and inspection, surveillance, and monitoring methods (ISMM). Stressors, the agents or stimuli that can produce aging degradation, include heat, radiation, volatile contaminants, and even normal concentrations of aerosol particles and gasses. In an experimental evaluation of degradation in terms of the tensile breaking strength of aged filter media specimens, over forty percent of the samples did not meet specifications for new material. Chemical and physical reactions can gradually embrittle sealants and gaskets as well as filter media. Mechanisms that can lead to impaired adsorber performance are associated with the loss of potentially available active sites as a result of the exposure of the carbon to airborne moisture or volatile organic compounds. Inspection, surveillance, and monitoring methods have been established to observe filter pressure drop buildup, check HEPA filters and adsorbers for bypass, and determine the retention effectiveness of aged carbon. These evaluations of installed filters do not reveal degradation in terms of reduced media strength but that under normal conditions aged media can continue to effectively retain particles. However, this degradation may be important when considering the likelihood of moisture, steam, and higher particle loadings during severe accidents and the fact it is probable that the filters have been in use for an extended period.

Analysis of an MCU HEPA filter

Energy Technology Data Exchange (ETDEWEB)

Peters, T. B. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Fondeur, F. F. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2017-01-01

A series of direct analyses on three portions (inlet, center, and outlet) of the High Efficiency Particulate Air (HEPA) filter material from the Modular Caustic-Side Solvent Extraction Unit (MCU) have been performed; this includes x-ray methods such as X-Ray Diffraction (XRD), Contained Scanning Electron Microscopy (CSEM) and X-Ray Fluorescence (XRF), as well as Fourier Transform InfraRed spectroscopy (FTIR). Additionally, two leaching studies (one with water, one with dichloromethane) have been performed on three portions (inlet, center, and outlet) of the HEPA filter material, with the leachates being analyzed by Inductively-coupled plasma emission spectroscopy (ICPES), Semi-Volatile Organic Analysis (SVOA) and gammascan. From the results of the analyses, SRNL feels that cesium-depleted solvent is being introduced into the HEPA filter. The most likely avenue for this is mechanical aerosolization of solvent, where the aerosol is then carried along an airstream into the HEPA filter. Once introduced into the HEPA filter media, the solvent wicks throughout the material, and migrates towards the outlet end. Once on the outlet end, continual drying could cause particulate flakes to exit the filter and travel farther down the airstream path.

Operation strategy of industrial crystallization for the production of 2,3,4,4'-tetrahydroxybenzophenon

Energy Technology Data Exchange (ETDEWEB)

Kim, Do Yeon; Yang, Dae Ryook [Korea University, Seoul (Korea, Republic of)

2015-07-15

To improve the filterability of hydroxybenzophenone crystal, a cooling strategy for the cooling crystallization process is investigated by examining the solubility and growth kinetics of hydroxybenzophenone. The operating strategy is divided into two steps. The first step is to generate the seed by dissolving the raw material and by changing operating conditions. The second step is to grow seeds to the product with desired crystal size distribution. For each part, an operating strategy has been proposed based on the solid-liquid phase equilibrium data in a ternary system and growth kinetic experimental results. The strategy for the first step is experimentally determined under various operating conditions, and the second one is determined by theoretical modeling and model-based optimization. The average crystal size resulting from the proposed strategy has been improved and the filterability has been enhanced compared to an existing strategy used in the industry.

Operation strategy of industrial crystallization for the production of 2,3,4,4'-tetrahydroxybenzophenon

International Nuclear Information System (INIS)

Kim, Do Yeon; Yang, Dae Ryook

2015-01-01

To improve the filterability of hydroxybenzophenone crystal, a cooling strategy for the cooling crystallization process is investigated by examining the solubility and growth kinetics of hydroxybenzophenone. The operating strategy is divided into two steps. The first step is to generate the seed by dissolving the raw material and by changing operating conditions. The second step is to grow seeds to the product with desired crystal size distribution. For each part, an operating strategy has been proposed based on the solid-liquid phase equilibrium data in a ternary system and growth kinetic experimental results. The strategy for the first step is experimentally determined under various operating conditions, and the second one is determined by theoretical modeling and model-based optimization. The average crystal size resulting from the proposed strategy has been improved and the filterability has been enhanced compared to an existing strategy used in the industry

Evaluation of self-contained HEPA filter

Energy Technology Data Exchange (ETDEWEB)

Arndt, T.E. [Westinghouse Hanford Company, Richland, WA (United States)

1995-02-01

This paper presents the results of an evaluation of a self-contained high-efficiency particulate air filter (SHEPA) used in nuclear applications. A SCHEPA consists of filter medium encapsulated in a casing that is part of the system boundary. The SCHEPA filter serves as a combination of filter housing and filter. The filter medium is attached directly to the casing using adhesive as a bonding agent. A cylindrical connection in the middle of the end caps connects the filter assembly to adjoining ductwork. The SCHEPA must perform the functions of a filter housing, filter frame, and filter. It was recognized that the codes and standards do not address the SCHEPA specifically. Therefore, the investigation evaluated the SCHEPA against current codes and standards related to the functional requirements of an air-cleaning system. The specific standards used are required by DOE Order 6430.1A{sup 1} and include ASME N509{sup 3}, ASME N510{sup 4}, ERDA 76-21{sup 5}, MIL-F-51068F{sup 6}, NFPA 90A, {sup 7} and NFPA 91{sup 8}. The evaluation does not address whether the SCHEPA as a standard (off-the-shelf) filter could be upgraded to meet the current code requirements for an air-cleaning unit. The evaluation also did not consider how the SCHEPA was used in a system (e.g., whether it was under positive or negative pressure or whether it served as an air inlet filter to prevent contamination releases under system pressurization). The results of the evaluation show that, the SCHEPA filter does not meet design, fabrication, testing, and documentation requirements of ASME N509{sup 3} and ASME N510{sup 4}. The paper will identify these deficiencies. Specific exhaust system requirements and application should be considered when an evaluation of the SCHEPA filter is being performed in existing systems. When new designs are being comtemplated, other types of HEPA filter housings can be used in lieu of the SCHEPA filter.

Magnon band structure and magnon density in one-dimensional magnonic crystals

International Nuclear Information System (INIS)

Qiu, Rong-ke; Huang, Te; Zhang, Zhi-dong

2014-01-01

By using Callen's Green's function method and the Tyablikov and Anderson–Callen decoupling approximations, we systematically study the magnon band structure and magnon density perpendicular to the superlattice plane of one-dimensional magnonic crystals, with a superlattice consisting of two magnetic layers with ferromagnetic (FM) or antiferromagnetic (AFM) interlayer exchange coupling. The effects of temperature, interlayer coupling, anisotropy and external magnetic field on the magnon-energy band and magnon density in the K x -direction are investigated in three situations: a) the magnon band of magnetic superlattices with FM interlayer coupling, b) separate and c) overlapping magnon bands of magnetic superlattices with AFM interlayer coupling. In the present work, a quantum approach is developed to study the magnon band structure and magnon density of magnonic crystals and the results are beneficial for the design of magnonic-crystal waveguides or gigahertz-range spin-wave filters. - Highlights: • A quantum approach has been developed to study the magnon band of magnonic crystals. • The separate and overlapping magnon bands of magnetic superlattices are investigated. • The results are beneficial for the design of gigahertz-range spin-wave filters

Magnon band structure and magnon density in one-dimensional magnonic crystals

Energy Technology Data Exchange (ETDEWEB)

Qiu, Rong-ke, E-mail: rkqiu@163.com [Shenyang University of Technology, Shenyang 110870 (China); Huang, Te [Shenyang University of Technology, Shenyang 110870 (China); Zhang, Zhi-dong [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China)

2014-11-15

By using Callen's Green's function method and the Tyablikov and Anderson–Callen decoupling approximations, we systematically study the magnon band structure and magnon density perpendicular to the superlattice plane of one-dimensional magnonic crystals, with a superlattice consisting of two magnetic layers with ferromagnetic (FM) or antiferromagnetic (AFM) interlayer exchange coupling. The effects of temperature, interlayer coupling, anisotropy and external magnetic field on the magnon-energy band and magnon density in the K{sub x}-direction are investigated in three situations: a) the magnon band of magnetic superlattices with FM interlayer coupling, b) separate and c) overlapping magnon bands of magnetic superlattices with AFM interlayer coupling. In the present work, a quantum approach is developed to study the magnon band structure and magnon density of magnonic crystals and the results are beneficial for the design of magnonic-crystal waveguides or gigahertz-range spin-wave filters. - Highlights: • A quantum approach has been developed to study the magnon band of magnonic crystals. • The separate and overlapping magnon bands of magnetic superlattices are investigated. • The results are beneficial for the design of gigahertz-range spin-wave filters.

Performance of sand filters for the separations areas at the Savannah River Laboratory

International Nuclear Information System (INIS)

Orth, D.A.; Sykes, G.H.; McKibben, J.M.

1981-01-01

Two new large sand filters, 30.5 by 100 m, were constructed and put into service at the Savannah River Plant (SRP) in 1975 and 1976. These units were designed to provide final filtration of process air - one for each of the two separations areas. Eventual flow will be 4950 m 3 /min (205,000 scfm) on each unit when all facilities are connected. They were built as replacements for the original sand filters that began operation in 1954 and 1955. The new filters have been operated in parallel with the old units following partial failure of the old units from acid attack and erosion of the concrete support structure for the sand beds. The design of the new units was based on extensive tests at SRP on characteristics of different sands. The performance of the new filters meets criteria for pressure drop, flow capacity, and efficiency. The efficiencies measured by DOP test are greater than 99.98%. Parallel operation reduces air velocity through the beds, which increases efficiency. A characteristic of sand filter performance has been low apparent efficiency at low input; efficiency increases as the activity input rises. This is attributed to a small entrainment release from the large amount of activity already sorbed on the filter; this release controls and lowers the calculated efficiency at low input. An analysis of efficiency as a function of input activity projects efficiencies greater than 99.99% for large inputs that might be characteristic of large internal accidents. The data indicate that DOP efficiencies can be used in hazards analyses to determine accident consequences. Routine evaluation of filter releases can be used for surveillance to establish that performance is normal at other times

PIXE analysis of atmospheric particulate matter in glas fibre filters

International Nuclear Information System (INIS)

Tabacniks, M.H.; Orsini, C.Q.; Maenhaut, W.

1993-01-01

A 3-step extraction procedure was developed to allow particle-induced X-ray emission (PIXE) analysis of particulate matter in normal glass fibre filter samples. The detection limits, expressed in ng/m 3 of air, for the filter extracts were 5 to 30 times lower than those achieved by PIXE analysis or ordinary Nuclepore polycarbonate filter samples. The concentration results were compared with those obtained from routine atomic absorption spectrometry measurements and with the PIXE data from Nuclepore stacked filter unit samples taken in parallel. (orig.)

Tunable Microwave Filter Design Using Thin-Film Ferroelectric Varactors

Science.gov (United States)

Haridasan, Vrinda

Military, space, and consumer-based communication markets alike are moving towards multi-functional, multi-mode, and portable transceiver units. Ferroelectric-based tunable filter designs in RF front-ends are a relatively new area of research that provides a potential solution to support wideband and compact transceiver units. This work presents design methodologies developed to optimize a tunable filter design for system-level integration, and to improve the performance of a ferroelectric-based tunable bandpass filter. An investigative approach to find the origins of high insertion loss exhibited by these filters is also undertaken. A system-aware design guideline and figure of merit for ferroelectric-based tunable band- pass filters is developed. The guideline does not constrain the filter bandwidth as long as it falls within the range of the analog bandwidth of a system's analog to digital converter. A figure of merit (FOM) that optimizes filter design for a specific application is presented. It considers the worst-case filter performance parameters and a tuning sensitivity term that captures the relation between frequency tunability and the underlying material tunability. A non-tunable parasitic fringe capacitance associated with ferroelectric-based planar capacitors is confirmed by simulated and measured results. The fringe capacitance is an appreciable proportion of the tunable capacitance at frequencies of X-band and higher. As ferroelectric-based tunable capac- itors form tunable resonators in the filter design, a proportionally higher fringe capacitance reduces the capacitance tunability which in turn reduces the frequency tunability of the filter. Methods to reduce the fringe capacitance can thus increase frequency tunability or indirectly reduce the filter insertion-loss by trading off the increased tunability achieved to lower loss. A new two-pole tunable filter topology with high frequency tunability (> 30%), steep filter skirts, wide stopband

Crystallization of carbohydrate oxidase from Microdochium nivale

International Nuclear Information System (INIS)

Dušková, Jarmila; Dohnálek, Jan; Skálová, Tereza; Østergaard, Lars Henrik; Fuglsang, Claus Crone; Kolenko, Petr; Štěpánková, Andrea; Hašek, Jindřich

2009-01-01

Industrially used carbohydrate oxidase was successfully crystallized in several forms, diffraction data suitable for structural analysis were collected. Microdochium nivale carbohydrate oxidase was produced by heterologous recombinant expression in Aspergillus oryzae, purified and crystallized. The enzyme crystallizes with varying crystal morphologies depending on the crystallization conditions. Several different crystal forms were obtained using the hanging-drop vapour-diffusion method, two of which were used for diffraction measurements. Hexagon-shaped crystals (form I) diffracted to 2.66 Å resolution, with unit-cell parameters a = b = 55.7, c = 610.4 Å and apparent space group P6 2 22. Analysis of the data quality showed almost perfect twinning of the crystals. Attempts to solve the structure by molecular replacement did not give satisfactory results. Recently, clusters of rod-shaped crystals (form II) were grown in a solution containing PEG MME 550. These crystals belonged to the monoclinic system C2, with unit-cell parameters a = 132.9, b = 56.6, c = 86.5 Å, β = 95.7°. Data sets were collected to a resolution of 2.4 Å. The structure was solved by the molecular-replacement method. Model refinement is currently in progress

Impact of a silver layer on the membrane of tap water filters on the microbiological quality of filtered water

Directory of Open Access Journals (Sweden)

Bruderek Juliane

2008-10-01

Full Text Available Abstract Background Bacteria in the hospital's drinking water system represent a risk for the acquisition of a nosocomial infection in the severely immunocompromised host. Terminal tap water filters may be used to prevent nosocomial Legionnaires' disease. We present data from water samples using an improved kind of tap water filters. Methods In a blinded study on an intermediate care unit of the thoracic surgery department, a modified type of the Germlyser water filter (Aqua-Free Membrane Technology with a newly-introduced silver layer on the filtration membrane was compared to its preceding type without such a layer on 15 water outlets. We determined growth of Legionella, other pathogenic bacteria, and the total heterotrophic plate count in unfiltered water and filtered water samples after filter usage intervals of 1 through 4 weeks. Results A total of 299 water samples were tested. Twenty-nine of the 60 unfiltered water samples contained Legionella of various serogroups (baseline value. In contrast, all samples filtered by the original water filter and all but one of the water samples filtered by the modified filter type remained Legionella-free. No other pathogenic bacteria were detected in any filtered sample. The total plate count in water samples increased during use of both kinds of filters over time. However, for the first 7 days of use, there were significantly fewer water samples containing >100 CFU per mL when using the new filter device compared with the older filters or taps with no filter. No advantage was seen thereafter. Conclusion The use of this type of terminal water filter is an appropriate method to protect immunocompromised patients from water-borne pathogens such as Legionella.

Crystal structure and thermal property of polyethylene glycol octadecyl ether

International Nuclear Information System (INIS)

Meng, Jie-yun; Tang, Xiao-fen; Li, Wei; Shi, Hai-feng; Zhang, Xing-xiang

2013-01-01

Highlights: ► The crystal structure of C18En for n ≥ 20 is a monoclinic system. ► Polyethylene glycol octadecyl ether crystallizes perfectly. ► The number of repeat units has significant effect on the melting, crystallizing temperature and enthalpy. ► The thermal stable temperature increases rapidly with increasing the number of repeat unit. - Abstract: The crystal structure, phase change property and thermal stable temperature (T d ) of polyethylene glycol octadecyl ether [HO(CH 2 CH 2 O) n C 18 H 37 , C18En] with various numbers of repeat units (n = 2, 10, 20 and 100) as phase change materials (PCMs) were investigated using temperature variable Fourier transformed infrared spectroscopy (FTIR), wide-angle X-ray diffraction (XRD), differential scanning calorimetry (DSC), and thermogravimetric analysis (TG). C18En crystallizes perfectly at 0 °C; and the crystal structure for n ≥ 20 is a monoclinic system. The number of repeat units has great effect on the phase change properties of C18En. The thermal stable temperature increases rapidly with increasing the number of repeat units. They approach to that of PEG-2000 as the number of repeat units is more than 10. T d increases rapidly with increasing the number of repeat units. C18En are a series of promising polymeric PCMs

Enhanced performance of a filter-sensor system.

Science.gov (United States)

Sasaki, Isao; Josowicz, Mira; Janata, Jirí; Glezer, Ari

2006-06-01

In this paper are addressed two important, but seemingly unrelated issues: long term performance of a gas sensing array and performance of an air purification unit. It is shown that when considered together, the system can be regarded as a "smart filter". The enhancement is achieved by periodic differential sampling and measurement of the "upstream" and "downstream" gases of a filter. The correctly functioning filter supplies the "zero gas" from the downstream for the continuous sensor baseline correction. A key element in this scheme is the synthetic jet that delivers well-defined pulses of the two gases. The deterioration of the performance of the "smart filter" can be diagnosed from the response pattern of the sensor. The approach has been demonstrated on removal/sensing of ammonia gas from air.

Employment of the technique of radiotracers for analysis of industrial filters

International Nuclear Information System (INIS)

Ramos, Vitor Santos; Crispim, Verginia Reis

2007-01-01

The main aim of this work is to develop a methodology to evaluate the characteristics of porous media in filter using the radio-tracing technique. To do this, an experimental prototype filter made up of an acrylic cylinder, vertically mounted and supported on the lower side by a controlled leaking valve was developed. Two filters (spheres of acrylic and silica crystals) were used to check the movement of the water through the porous media using 123 I in its MIBG (iodine-123-meta-iodo benzyl-guanidine) form. Further up the filter an instantaneous injection of the substance makes it possible to see the passage of radioactive clouds through the two scintillatory detectors NaI (2x2) ' ' positioned before and immediately after the cylinder with the filtering element (porous media). The are caused by the detectors on the passage of the radioactive cloud are analyzed through statistical functions using the weighted moment method which makes it possible to calculate the Residence-Time (the amount of time the tracer takes to thoroughly pass through the filter) per the equation of dispersion in tubular flow and the one-directional flow of the radiotracer in the porous media. (author)

Error Measurements in an Acousto-Optic Tunable Filter Fiber Bragg Grating Sensor System

Science.gov (United States)

1994-05-01

for an ideal AOTF, at 833 and 838 nm using a TeO2 crystal ............................ 33 Figure 3.12. Frequency characteristics of Equation (3.43...multiple channels in an AOTF requires the presence of multiple RF frequencies to establish the complex grating. Since the crystal used in the AOTF ( TeO2 ) is...in germano- silicate glass . This index modulation, Bragg grating, acts as an optical band rejection filter for those wavelengths that meet the Bragg

Modified-hybrid optical neural network filter for multiple object recognition within cluttered scenes

Science.gov (United States)

Kypraios, Ioannis; Young, Rupert C. D.; Chatwin, Chris R.

2009-08-01

Motivated by the non-linear interpolation and generalization abilities of the hybrid optical neural network filter between the reference and non-reference images of the true-class object we designed the modifiedhybrid optical neural network filter. We applied an optical mask to the hybrid optical neural network's filter input. The mask was built with the constant weight connections of a randomly chosen image included in the training set. The resulted design of the modified-hybrid optical neural network filter is optimized for performing best in cluttered scenes of the true-class object. Due to the shift invariance properties inherited by its correlator unit the filter can accommodate multiple objects of the same class to be detected within an input cluttered image. Additionally, the architecture of the neural network unit of the general hybrid optical neural network filter allows the recognition of multiple objects of different classes within the input cluttered image by modifying the output layer of the unit. We test the modified-hybrid optical neural network filter for multiple objects of the same and of different classes' recognition within cluttered input images and video sequences of cluttered scenes. The filter is shown to exhibit with a single pass over the input data simultaneously out-of-plane rotation, shift invariance and good clutter tolerance. It is able to successfully detect and classify correctly the true-class objects within background clutter for which there has been no previous training.

Crystallization of the class IV adenylyl cyclase from Yersinia pestis

International Nuclear Information System (INIS)

Smith, Natasha; Kim, Sook-Kyung; Reddy, Prasad T.; Gallagher, D. Travis

2006-01-01

The class IV adenylyl cyclase from Y. pestis has been crystallized in an orthorhombic form suitable for structure determination. The class IV adenylyl cyclase from Yersinia pestis has been cloned and crystallized in both a triclinic and an orthorhombic form. An amino-terminal His-tagged construct, from which the tag was removed by thrombin, crystallized in a triclinic form diffracting to 1.9 Å, with one dimer per asymmetric unit and unit-cell parameters a = 33.5, b = 35.5, c = 71.8 Å, α = 88.7, β = 82.5, γ = 65.5°. Several mutants of this construct crystallized but diffracted poorly. A non-His-tagged native construct (179 amino acids, MW = 20.5 kDa) was purified by conventional chromatography and crystallized in space group P2 1 2 1 2 1 . These crystals have unit-cell parameters a = 56.8, b = 118.6, c = 144.5 Å, diffract to 3 Å and probably have two dimers per asymmetric unit and V M = 3.0 Å 3 Da −1 . Both crystal forms appear to require pH below 5, complicating attempts to incorporate nucleotide ligands into the structure. The native construct has been produced as a selenomethionine derivative and crystallized for phasing and structure determination

Compact triple band-stop filter using novel epsilon-shaped metamaterial with lumped capacitor

Science.gov (United States)

Ali, W. A. E.; Hamdalla, M. Z. M.

2018-04-01

This paper presents the design of a novel epsilon-shaped metamaterial unit cell structure that is applicable for single-band and multi-band applications. A closed-form formulas to control the resonance frequencies of the proposed design are included. The proposed unit cell, which exhibits negative permeability at its frequency bands, is etched from the ground plane to form a band-stop filter. The filter design is constructed to validate the band-notched characteristics of the proposed unit cell. A lumped capacitor is inserted for size reduction purpose in addition to multi-resonance generation. The fundamental resonance frequency is translated from 3.62 GHz to 2.45 GHz, which means that the filter size will be more compact (more than 32% size reduction). The overall size of the proposed filter is 13 × 6 × 1.524 mm3, where the electrical size is 0.221λg × 0.102λg × 0.026λg at the lower frequency band (2.45 GHz). Two other resonance frequencies are generated at 5.3 GHz and 9.2 GHz, which confirm the multi-band behavior of the proposed filter. Good agreement between simulated and measured characteristics of the fabricated filter prototype is achieved.

Mini-stop bands in single heterojunction photonic crystal waveguides

KAUST Repository

Shahid, N.; Amin, M.; Naureen, S.; Anand, S.

2013-01-01

Spectral characteristics of mini-stop bands (MSB) in line-defect photonic crystal (PhC) waveguides and in heterostructure PhC waveguides having one abrupt interface are investigated. Tunability of the MSB position by air-fill factor heterostructure PhC waveguides is utilized to demonstrate different filter functions, at optical communication wavelengths, ranging from resonance-like to wide band pass filters with high transmission. The narrowest filter realized has a resonance-like transmission peak with a full width at half maximum of 3.4 nm. These devices could be attractive for coarse wavelength selection (pass and drop) and for sensing applications. 2013 Copyright 2013 Author(s). This article is distributed under a Creative Commons Attribution 3.0 Unported License.

The Application of Paired Parallel Filters for Ultra-Wideband Signal Processing

Directory of Open Access Journals (Sweden)

S. L. Chernyshev

2015-01-01

Full Text Available The paper considers a unit in which the parallel filters on regular lines are pair-attached. This connection allows to reduce a side line impedance at the point of connection. At the same time these lines become narrow, and the possibility to excite higher modes in the joint reduces.Consider the scattering matrix of four identical lines connection. Then find the scattering matrix of connection in which two side lines are connected with filters. Particular cases of the reflection coefficients of different filters are considered. It is shown that only in the case of identical filters there remained a linear relationship between the input filter coefficients of reflection and transmission coefficient of the unit. It facilitates the solution of the problem of synthesis. Restrictions on the transfer coefficient are found. In transition to the time domain impulse response of connection under consideration and the expression for the synthesis were defined. The paper considers an example of implementation of the matched filtering in this connection. In this case, the output signal is a half-sum of the input signal and their autocorrelation function.

Laboratory-scale integrated ARP filter test

Energy Technology Data Exchange (ETDEWEB)

Poirier, M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Burket, P. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2016-03-01

The Savannah River Site (SRS) is currently treating radioactive liquid waste with the Actinide Removal Process (ARP) and the Modular Caustic Side Solvent Extraction Unit (MCU). Recently, the low filter flux through the ARP of approximately 5 gallons per minute has limited the rate at which radioactive liquid waste can be treated. Salt Batch 6 had a lower processing rate and required frequent filter cleaning. There is a desire to understand the causes of the low filter flux and to increase ARP/MCU throughput. This task attempted to simulate the entire ARP process, including multiple batches (5), washing, chemical cleaning, and blending the feed with heels and recycle streams. The objective of the tests was to determine whether one of these processes is causing excessive fouling of the crossflow or secondary filter. The authors conducted the tests with feed solutions containing 6.6 M sodium Salt Batch 6 simulant supernate with no MST.

Tungsten anode tubes with K-edge filters for mammography

Energy Technology Data Exchange (ETDEWEB)

Beaman, S.; Lillicrap, S.C. (Wessex Regional Medical Physics Service, Bath (UK)); Price, J.L. (Jarvis Screening Centre, Guildford (UK))

1983-10-01

Optimum X-ray energies for mammography have previously been calculated using the maximum signal to noise ratio (SNR) per unit dose to the breast, or the minimum exposure for constant SNR. Filters having absorption edges at appropriate energy positions have been used to modify the shape of tungsten anode spectra towards the calculated optimum. The suitability of such spectra for practical use has been assessed by comparing the film image quality and the incident breast dose obtained using a K-edge filtered tungsten anode tube with that obtained using a molybdenum anode. Image quality has been assessed by using a 'random' phantom and by comparing mammograms where one breast was radiographed using a filtered tungsten anode tube and the other using a standard molybdenum anode unit. Relative breast doses were estimated from both ionisation chamber measurements with a phantom and thermoluminescent dosimetry measurements on the breast. Film image quality assessment indicated that the filtered tungsten anode tube gave results not significantly different from those obtained with a molybdenum anode tube for a tissue thickness of about 4 cm and which were better for larger breast thicknesses. Doses could be reduced to between one-half and one-third with the filtered tungsten anode tube.

Tungsten anode tubes with K-edge filters for mammography

International Nuclear Information System (INIS)

Beaman, S.; Lillicrap, S.C.; Price, J.L.

1983-01-01

Optimum X-ray energies for mammography have previously been calculated using the maximum signal to noise ratio (SNR) per unit dose to the breast, or the minimum exposure for constant SNR. Filters having absorption edges at appropriate energy positions have been used to modify the shape of tungsten anode spectra towards the calculated optimum. The suitability of such spectra for practical use has been assessed by comparing the film image quality and the incident breast dose obtained using a K-edge filtered tungsten anode tube with that obtained using a molybdenum anode. Image quality has been assessed by using a 'random' phantom and by comparing mammograms where one breast was radiographed using a filtered tungsten anode tube and the other using a standard molybdenum anode unit. Relative breast doses were estimated from both ionisation chamber measurements with a phantom and thermoluminescent dosimetry measurements on the breast. Film image quality assessment indicated that the filtered tungsten anode tube gave results not significantly different from those obtained with a molybdenum anode tube for a tissue thickness of abut 4 cm and which were better for larger breast thicknesses. Doses could be reduced to between one-half and one-third with the filtered tungsten anode tube. (U.K.)

Luminescent unit computerization to research spectral characteristics of fine film alkali halide crystal

International Nuclear Information System (INIS)

Zhalimbetov, T.; Zhabetov, A.; Moldagaliev, A.; Sarmukhanov, E.; Shunkeev, K.; Shunkeev, S.; Abdullin, K.; Tokmoldin, C.

2002-01-01

The fundamental optical absorption of ion crystals characterizes the creation of different free low energetic electronic excitation (the excitons and electron-hole pairs), but their straight registration is not possible because of incommensurable big absorption factor of alkali halide monocrystals. So to registration the spectrums of alkali halide monocrystal very fine layers are necessary. We have received fine films of Nal and KCl in system of KCl-Nal-KCl, KCl-KI-KCl on the base of universal vacuum post VUP-4, VUP-5 by thermal evaporation. A unique spectral unit has been created For this on the basic the SDL-2 complex. Complex consists of radiator, systems of condensers, monochromators MDR-12 and MDR-23, receivers of radiation, controller by unit. Connect and control of monochromators by means of IBM-compatible computer has been created. Kinematics schemes of monochromators provide consequent removing on output slot of monochromatic radiation in operating range of each diffraction lattice and indication its wavelength. The tumbling diffraction lattices is done the crossbar engines SHDR-711. For this special plate of control and block of reinforcement for crossbar engines in monochromators MDR-12 and MDR-23 are designed and constructed. Created controller of monochromators consists of double cascade preamplifier on transistors n-p-n type (815G) and logical scheme, constructed on summers and K555 series triggers. The preamplifier is used for reinforcement of signal to available amplifier on transistors KT837D. The logical scheme reduces the number of used categories of bidirectional port and enables unhooking the feeding to the windings of crossbar engine at conservation of previous combination of signals. The connection controller of monochromators is done through controller of port of computer with use the parallel interface. For installing computerized system of collection and data processing is provided marketed by means of modern object-oriented programming

A study on displacement of crystalline diffraction peaks in electron-beam irradiated filter paper cellulose

International Nuclear Information System (INIS)

Zhou Ruimin; Xiang Qun; Song Jing

1997-01-01

It is found that the crystalline diffraction angles of the electron-beam irradiated filter paper cellulose shift regularly when the irradiation dose is increased. The experiments indicate that the molecules between crystalline area and amorphous area in the filter paper cellulose will be degraded by the irradiation and the cellulose molecules in the surface of crystal will come off, thus the microcrystalline dimension will be reduced and the diffraction angle will become smaller. The fact that intensity of the 002 peak for filter paper samples decreases gradually with the increasing storage time can be attributed to the post-irradiation effect

Evaluation of prototype electrofibrous filters for nuclear ventilation ducts

International Nuclear Information System (INIS)

Bergman, W.; Kuhl, W.D.; Biermann, A.H.; Johnson, J.S.; Lum, B.Y.

1983-01-01

Two prototype electrofibrous filters were designed, built and evaluated in laboratory tests and in field installations. These prototypes were designed for use in nuclear ventilation ducts as prefilters to HEPA filters. One prototype is designed to be a permanent component of the ventilation system while the other is a disposable unit. The disposable electrofibrous prefilter was installed in the exhaust stream of a glove box in which barrels of uranium turnings are burned. Preliminary tests show the disposable prefilter is effectively prolonging the HEPA filter life

Evaluation of prototype electrofibrous filters for nuclear-ventilation ducts

International Nuclear Information System (INIS)

Bergman, W.; Kuhl, W.D.; Biermann, A.H.; Johnson, J.S.; Lum, B.Y.

1982-01-01

Two prototypes electrofibrous filters were designed, built and evaluated in laboratory tests and in field installations. These prototypes were designed for use in nuclear ventilation ducts as prefilters to HEPA filters. One prototype is designed to be a permanent component of the ventilation system while the other is a disposable unit. The disposable electrofibrous prefilter was installed in the exhaust stream of a glove box in which barrels of uranium turnings are burned. Preliminary tests show the disposable prefilter is effectively prolonging the HEPA filter life

Ultra scaledown to predict filtering centrifugation of secreted antibody fragments from fungal broth.

Science.gov (United States)

Boulding, N; Yim, S S S; Keshavarz-Moore, E; Ayazi Shamlou, P; Berry, M

2002-08-20

Extracellularly expressed anti-hen egg lysozyme single-chain antibody fragments (scFv) produced by Aspergillus awamori were recovered using filtering centrifugation. Two filtering centrifuges with 0.5- and 30-L capacities were used to represent laboratory- and pilot-scale equipment, respectively. Critical regime analysis using the computational fluid dynamics (CFD) technique provided information about the local energy dissipation rates in both units. Experimental data indicated loss of scFv activity for energy dissipation rates above about 2.0 x 10(4) W kg(-1). This loss of activity increased in the presence of gas-liquid interfaces during filtering centrifugation. An ultra scaledown filtering centrifuge with a maximum working volume of 35 mL was designed to mimic the operating conditions identified by the critical regime analysis for the laboratory- and pilot-plant-scale units. The recovered scFv activity levels and the separation performance of the three units were comparable when operated at equal maximum energy dissipation rates. Copyright 2002 Wiley Periodicals, Inc.

On the use of lead as a neutron filter

Energy Technology Data Exchange (ETDEWEB)

Adib, M.; Naguib, K.; Ashry, A.; Fathalla, M. E-mail: mohamedfathallah@hotmail.com

2002-06-01

A generalized formula is given which allows to calculate the contribution of the total neutron cross-section including the Bragg scattering from different (hkl) planes to the neutron transmission through a solid crystalline material. The formula takes into account the crystalline form of the material (poly- or mono-crystal) and crystal parameters. A computer program ISCANF-II was developed to provide the required calculations. The calculated values of the neutron transmission through a lead single crystal cut along the (311) plane were compared with the previously measured ones in the wavelength range 0.03 to 0.52 nm. The measured and calculated values were found to be in reasonable agreement within the statistical accuracy. The feasibility study on using a poly-crystalline lead as a cold neutron filter and mono-crystalline as a thermal neutron one is given. The optimum crystal thickness, temperature and characteristics for efficiently transmitting the thermal reactor neutrons, while removing simultaneously fast neutrons and gamma rays accompanying the thermal ones for the both cases are given.

On the use of lead as a neutron filter

International Nuclear Information System (INIS)

Adib, M.; Naguib, K.; Ashry, A.; Fathalla, M.

2002-01-01

A generalized formula is given which allows to calculate the contribution of the total neutron cross-section including the Bragg scattering from different (hkl) planes to the neutron transmission through a solid crystalline material. The formula takes into account the crystalline form of the material (poly- or mono-crystal) and crystal parameters. A computer program ISCANF-II was developed to provide the required calculations. The calculated values of the neutron transmission through a lead single crystal cut along the (311) plane were compared with the previously measured ones in the wavelength range 0.03 to 0.52 nm. The measured and calculated values were found to be in reasonable agreement within the statistical accuracy. The feasibility study on using a poly-crystalline lead as a cold neutron filter and mono-crystalline as a thermal neutron one is given. The optimum crystal thickness, temperature and characteristics for efficiently transmitting the thermal reactor neutrons, while removing simultaneously fast neutrons and gamma rays accompanying the thermal ones for the both cases are given

Failure of action potential propagation in sensory neurons: mechanisms and loss of afferent filtering in C-type units after painful nerve injury.

Science.gov (United States)

Gemes, Geza; Koopmeiners, Andrew; Rigaud, Marcel; Lirk, Philipp; Sapunar, Damir; Bangaru, Madhavi Latha; Vilceanu, Daniel; Garrison, Sheldon R; Ljubkovic, Marko; Mueller, Samantha J; Stucky, Cheryl L; Hogan, Quinn H

2013-02-15

The T-junction of sensory neurons in the dorsal root ganglion (DRG) is a potential impediment to action potential (AP) propagation towards the CNS. Using intracellular recordings from rat DRG neuronal somata during stimulation of the dorsal root, we determined that the maximal rate at which all of 20 APs in a train could successfully transit the T-junction (following frequency) was lowest in C-type units, followed by A-type units with inflected descending limbs of the AP, and highest in A-type units without inflections. In C-type units, following frequency was slower than the rate at which AP trains could be produced in either dorsal root axonal segments or in the soma alone, indicating that the T-junction is a site that acts as a low-pass filter for AP propagation. Following frequency was slower for a train of 20 APs than for two, indicating that a cumulative process leads to propagation failure. Propagation failure was accompanied by diminished somatic membrane input resistance, and was enhanced when Ca(2+)-sensitive K(+) currents were augmented or when Ca(2+)-sensitive Cl(-) currents were blocked. After peripheral nerve injury, following frequencies were increased in axotomized C-type neurons and decreased in axotomized non-inflected A-type neurons. These findings reveal that the T-junction in sensory neurons is a regulator of afferent impulse traffic. Diminished filtering of AP trains at the T-junction of C-type neurons with axotomized peripheral processes could enhance the transmission of activity that is ectopically triggered in a neuroma or the neuronal soma, possibly contributing to pain generation.

Crystallization and Characterization of Galdieria sulphuraria RUBISCO in Two Crystal Forms: Structural Phase Transition Observed in P21 Crystal Form

Directory of Open Access Journals (Sweden)

Boguslaw Stec

2007-10-01

Full Text Available We have isolated ribulose-1,5-bisphosphate-carboxylase/oxygenase (RUBISCOfrom the red algae Galdieria Sulphuraria. The protein crystallized in two different crystalforms, the I422 crystal form being obtained from high salt and the P21 crystal form beingobtained from lower concentration of salt and PEG. We report here the crystallization,preliminary stages of structure determination and the detection of the structural phasetransition in the P21 crystal form of G. sulphuraria RUBISCO. This red algae enzymebelongs to the hexadecameric class (L8S8 with an approximate molecular weight 0.6MDa.The phase transition in G. sulphuraria RUBISCO leads from two hexadecamers to a singlehexadecamer per asymmetric unit. The preservation of diffraction power in a phasetransition for such a large macromolecule is rare.

Thermal neutron filter design for the neutron radiography facility at the LVR-15 reactor

Energy Technology Data Exchange (ETDEWEB)

Soltes, Jaroslav [Research Centre Rez Ltd., Husinec - Rez 130, 250 68 Rez, (Czech Republic); Faculty of Nuclear Sciences and Physical Engineering, CTU in Prague, (Czech Republic); Viererbl, Ladislav; Lahodova, Zdena; Koleska, Michal; Vins, Miroslav [Research Centre Rez Ltd., Husinec - Rez 130, 250 68 Rez, (Czech Republic)

2015-07-01

In 2011 a decision was made to build a neutron radiography facility at one of the unused horizontal channels of the LVR-15 research reactor in Rez, Czech Republic. One of the key conditions for operating an effective radiography facility is the delivery of a high intensity, homogeneous and collimated thermal neutron beam at the sample location. Additionally the intensity of fast neutrons has to be kept as low as possible as the fast neutrons may damage the detectors used for neutron imaging. As the spectrum in the empty horizontal channel roughly copies the spectrum in the reactor core, which has a high ratio of fast neutrons, neutron filter components have to be installed inside the channel in order to achieve desired beam parameters. As the channel design does not allow the instalment of complex filters and collimators, an optimal solution represent neutron filters made of large single-crystal ingots of proper material composition. Single-crystal silicon was chosen as a favorable filter material for its wide availability in sufficient dimensions. Besides its ability to reasonably lower the ratio of fast neutrons while still keeping high intensities of thermal neutrons, due to its large dimensions, it suits as a shielding against gamma radiation from the reactor core. For designing the necessary filter dimensions the Monte-Carlo MCNP transport code was used. As the code does not provide neutron cross-section libraries for thermal neutron transport through single-crystalline silicon, these had to be created by approximating the theory of thermal neutron scattering and modifying the original cross-section data which are provided with the code. Carrying out a series of calculations the filter thickness of 1 m proved good for gaining a beam with desired parameters and a low gamma background. After mounting the filter inside the channel several measurements of the neutron field were realized at the beam exit. The results have justified the expected calculated values

Potential of simple filters to improve microbial quality of irrigation water used in urban vegetable farming in Ghana

DEFF Research Database (Denmark)

Keraita, Bernard; Drechsel, Pay; Konradsen, Flemming

2008-01-01

. As part of a larger study on possible interventions for health risk reduction, the potential of simple interventions was explored. Column slow sand filters with three levels of sand depths (0.5 m, 0.75 m and 1 m) and fabric filters made of nylon, cotton and netting were assessed. More than 600 water...... samples were analyzed for helminth eggs and thermotolerant coliforms. Flow rates were also measured. From slow sand filters, 71-96% of helminths and 2 log units (from 7 to 5 log units) of thermotolerant coliforms were removed. Sand depths had no significant influence in the removal. Lower removal rates...... were achieved by fabric filters, with an average removal of 12-62% for helminth eggs and 1 log unit for thermotolerant coliforms. Nylon filters had higher removal rates especially for helminth eggs (58%). Average flow rates for sand filters were 3 m per day and fabric filters had steady flows of about...

Low-loss tunable all-in-fiber filter for Raman spectroscopy

DEFF Research Database (Denmark)

Brunetti, Anna Chiara; Scolari, Lara; Lund-Hansen, Toke

2011-01-01

We show a novel in-line Rayleigh-rejection filter for Raman spectroscopy, based on a solid-core Photonic Crystal Fiber (PCF) filled with a high-index material. The device is low-loss and thermally tunable, and allows for a strong attenuation of the Rayleigh line at 532nm and the transmission...... of the Raman lines in a broad wavenumber range....

The fluence research of filter material for fast neutron fluence measurement

International Nuclear Information System (INIS)

Tang Xiding

2010-01-01

When the fast neutron fluence is measured by radioactivation techniques in the nuclear reactor the fast neutron is also filtered a little by the thermal neutron filter material, and if the filter material thickness increase the filtered fast neutron increases therewith. For fast neutron fluenc measurement, there are only cadmium, boron and gadolinium three elements filtering fluence can be calculated ordinarily. In order to calculate the filtered fast neutron fluence of the all elements in the filter material, the many total cross sections of nuclides had checked out from nuclear cross section data library, converted them into the same energy group structure, then element's total cross section, compound's total cross section and multilayer filters' total cross section had calculated from these total cross sections with same energy group structure, a new cross section data library can be obtained lastly through merging these cross sections into the old cross section data library used for neutron fluence measurement. The calculation analysis indicates that the results of the unit 2 surveillance capsule U of DAYA Bay NPP and the unit 1 surveillance capsule A of the Second Nuclear Power Plant of Qinshan by considering the all elements subtracting iron are smaller about 1.5% and 2.6% respectively than the ones only to consider cadmium, boron. The old measured results accord with the new values under the measurement uncertainty, are reliable. The new results are more accuracy. (authors)

Crystal growth and properties of novel organic nonlinear optical crystals of 4-Nitrophenol urea

Energy Technology Data Exchange (ETDEWEB)

Mohan, M. Krishna, E-mail: krishnamohan.m@ktr.srmuniv.ac.in; Ponnusamy, S.; Muthamizhchelvan, C.

2017-07-01

Single crystals of 4-Nitrophenol urea have been grown from water using slow evaporation technique at constant temperature, with the vision to improve the properties of the crystals. The unit cell parameters of the grown crystals were determined by single crystal and powder X-Ray diffraction. FTIR studies reveals the presence of different vibrational bands. The Optical studies confirmed that the crystal is transparent up to 360 nm .TGA and DSC studies were carried out to understand the thermal behavior of crystals. The SHG studies show the suitability of the crystals for NLO applications. The etching studies were carried out to study the behavior of the crystals under different conditions.These studies reveal that the crystals of 4-Nitrophenol urea are suitable for device applications. - Highlights: • 4-Nitrophenol urea crystals of dimensions 14 mm × 1 mm were grown. • UV–Visible studies indicate the crystal is transparent in the region of 370–800 nm. • Thermal studies show the crystal starts decomposing at 170 °C. • SHG studies indicate that the crystals have NLO efficiency 3.5 times that of KDP.

Impact Of Sodium Oxalate, Sodium Aluminosilicate, and Gibbsite/Boehmite on ARP Filter Performance

Energy Technology Data Exchange (ETDEWEB)

Poirier, M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Burket, P. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2015-11-01

The Savannah River Site (SRS) is currently treating radioactive liquid waste with the Actinide Removal Process (ARP) and the Modular Caustic Side Solvent Extraction Unit (MCU). Recently, the low filter flux through the ARP of approximately 5 gallons per minute has limited the rate at which radioactive liquid waste can be treated. Salt Batch 6 had a lower processing rate and required frequent filter cleaning. Savannah River Remediation (SRR) has a desire to understand the causes of the low filter flux and to increase ARP/MCU throughput. SRR requested SRNL to conduct bench-scale filter tests to evaluate whether sodium oxalate, sodium aluminosilicate, or aluminum solids (i.e., gibbsite and boehmite) could be the cause of excessive fouling of the crossflow or secondary filter at ARP. The authors conducted the tests by preparing slurries containing 6.6 M sodium Salt Batch 6 supernate, 2.5 g MST/L slurry, and varying concentrations of sodium oxalate, sodium aluminosilicate, and aluminum solids, processing the slurry through a bench-scale filter unit that contains a crossflow primary filter and a dead-end secondary filter, and measuring filter flux and transmembrane pressure as a function of time. Among the conclusions drwn from this work are the following: (1) All of the tests showed some evidence of fouling the secondary filter. This fouling could be from fine particles passing through the crossflow filter. (2) The sodium oxalate-containing feeds behaved differently from the sodium aluminosilicate- and gibbsite/boehmite-containing feeds.

Variable-metric diffraction crystals for x-ray optics

International Nuclear Information System (INIS)

Smither, R.K.; Fernandez, P.B.

1992-01-01

A variable-metric (VM) crystal is one in which the spacing between the crystalline planes changes with position in the crystal. This variation can be either parallel to the crystalline planes or perpendicular to the crystalline planes of interest and can be produced by either introducing a thermal gradient in the crystal or by growing a crystal made of two or more elements and changing the relative percentages of the two elements as the crystal is grown. A series of experiments were performed in the laboratory to demonstrate the principle of the variable-metric crystal and its potential use in synchrotron beam lines. One of the most useful applications of the VM crystal is to increase the number of photons per unit bandwidth in a diffracted beam without losing any of the overall intensity. In a normal synchrotron beam line that uses a two-crystal monochromator, the bandwidth of the diffracted photon beam is determined by the vertical opening angle of the beam which is typically 0.10--0.30 mrad or 20--60 arcsec. When the VM crystal approach is applied, the bandwidth of the beam can be made as narrow as the rocking curve of the diffracting crystal, which is typically 0.005--0.050 mrad or 1--10 arcsec. Thus a very large increase of photons per unit bandwidth (or per unit energy) can be achieved through the use of VM crystals. When the VM principle is used with bent crystals, new kinds of x-ray optical elements can be generated that can focus and defocus x-ray beams much like simple lenses where the focal length of the lens can be changed to match its application. Thus both large magnifications and large demagnifications can be achieved as well as parallel beams with narrow bandwidths

A program for the derivation of crystal unit cell parameters from X-ray powder diffraction measurements

International Nuclear Information System (INIS)

Ferguson, I.F.; Rogerson, A.H.

1984-01-01

The program, FIRESTAR, determines the dimensions of a crystallographic unit cell from a set of X-ray powder diffraction measurements corresponding to a set of Bragg reflections, provided that the crystal system applicable is known and the Bragg reflections have been indexed. The program includes a range of possible extrapolation functions, and the data may be weighted. Provision is made for detecting and rejecting a single 'bad' measurement, and then rejecting measurements which lie outside an error limit set in the input data. (orig.)

Replicating the microbial community and water quality performance of full-scale slow sand filters in laboratory-scale filters.

Science.gov (United States)

Haig, Sarah-Jane; Quince, Christopher; Davies, Robert L; Dorea, Caetano C; Collins, Gavin

2014-09-15

Previous laboratory-scale studies to characterise the functional microbial ecology of slow sand filters have suffered from methodological limitations that could compromise their relevance to full-scale systems. Therefore, to ascertain if laboratory-scale slow sand filters (L-SSFs) can replicate the microbial community and water quality production of industrially operated full-scale slow sand filters (I-SSFs), eight cylindrical L-SSFs were constructed and were used to treat water from the same source as the I-SSFs. Half of the L-SSFs sand beds were composed of sterilized sand (sterile) from the industrial filters and the other half with sand taken directly from the same industrial filter (non-sterile). All filters were operated for 10 weeks, with the microbial community and water quality parameters sampled and analysed weekly. To characterize the microbial community phyla-specific qPCR assays and 454 pyrosequencing of the 16S rRNA gene were used in conjunction with an array of statistical techniques. The results demonstrate that it is possible to mimic both the water quality production and the structure of the microbial community of full-scale filters in the laboratory - at all levels of taxonomic classification except OTU - thus allowing comparison of LSSF experiments with full-scale units. Further, it was found that the sand type composing the filter bed (non-sterile or sterile), the water quality produced, the age of the filters and the depth of sand samples were all significant factors in explaining observed differences in the structure of the microbial consortia. This study is the first to the authors' knowledge that demonstrates that scaled-down slow sand filters can accurately reproduce the water quality and microbial consortia of full-scale slow sand filters. Copyright © 2014 Elsevier Ltd. All rights reserved.

Slow neutron total cross-section, transmission and reflection calculation for poly- and mono-NaCl and PbF{sub 2} crystals

Energy Technology Data Exchange (ETDEWEB)

Mansy, Muhammad S., E-mail: mmansy88@asrt.sci.eg [Reactor Physics Department, Nuclear Research Centre, Atomic Energy Authority, Cairo (Egypt); Radioactive Waste Management Unit, Hot Labs Centre, Atomic Energy Authority, Cairo (Egypt); Adib, M.; Habib, N. [Reactor Physics Department, Nuclear Research Centre, Atomic Energy Authority, Cairo (Egypt); Bashter, I.I. [Physics Department, Faculty of Science, Zagazig University (Egypt); Morcos, H.N.; El-Mesiry, M.S. [Reactor Physics Department, Nuclear Research Centre, Atomic Energy Authority, Cairo (Egypt)

2016-10-01

Highlights: • Slow neutron cross-section calculation for poly- and mono-crystalline materials. • Monochromatic features of PbF{sub 2} and NaCl mono-crystals. • Characterization of poly- and mono-crystal filters used in neutron diffraction. • Computer code developed calculates neutron cross-section, transmission & reflection. - Abstract: A detailed study about the calculation of total neutron cross-section, transmission and reflection from crystalline materials was performed. The developed computer code is approved to be sufficient for the required calculations, also an excellent agreement has been shown when comparing the code results with the other calculated and measured values. The optimal monochromator and filter parameters were discussed in terms of crystal orientation, mosaic spread, and thickness. Calculations show that 30 cm thick of PbF{sub 2} poly-crystal is an excellent cold neutron filter producing neutron wavelengths longer than 0.66 nm needed for the investigation of magnetic structure experiments. While mono-crystal filter PbF{sub 2} cut along its (1 1 1), having mosaic spread (η = 0.5°) and thickness 10 cm can only transmit thermal neutrons of the desired wavelengths and suppress epithermal and γ-rays forming unwanted background, when it is cooled to liquid nitrogen temperature. NaCl (2 0 0) and PbF{sub 2} (1 1 1) monochromator crystals having mosaic spread (η = 0.5°) and thickness 10 mm shows high neutron reflectivity for neutron wavelengths (λ = 0.114 nm and λ = 0.43 nm) when they used as a thermal and cold neutron monochromators respectively with very low contamination from higher order reflections.

Phononic Crystal Waveguide Transducers for Nonlinear Elastic Wave Sensing.

Science.gov (United States)

Ciampa, Francesco; Mankar, Akash; Marini, Andrea

2017-11-07

Second harmonic generation is one of the most sensitive and reliable nonlinear elastic signatures for micro-damage assessment. However, its detection requires powerful amplification systems generating fictitious harmonics that are difficult to discern from pure nonlinear elastic effects. Current state-of-the-art nonlinear ultrasonic methods still involve impractical solutions such as cumbersome signal calibration processes and substantial modifications of the test component in order to create material-based tunable harmonic filters. Here we propose and demonstrate a valid and sensible alternative strategy involving the development of an ultrasonic phononic crystal waveguide transducer that exhibits both single and multiple frequency stop-bands filtering out fictitious second harmonic frequencies. Remarkably, such a sensing device can be easily fabricated and integrated on the surface of the test structure without altering its mechanical and geometrical properties. The design of the phononic crystal structure is supported by a perturbative theoretical model predicting the frequency band-gaps of periodic plates with sinusoidal corrugation. We find our theoretical findings in excellent agreement with experimental testing revealing that the proposed phononic crystal waveguide transducer successfully attenuates second harmonics caused by the ultrasonic equipment, thus demonstrating its wide range of potential applications for acousto/ultrasonic material damage inspection.

Expression, purification and crystallization of Streptococcus dysgalactiae-derived mitogen

International Nuclear Information System (INIS)

Papageorgiou, Anastassios C.; Saarinen, Susanna; Ramirez-Bartutis, Rosa; Kato, Hidehito; Uchiyama, Takehiko; Kirikae, Teruo; Miyoshi-Akiyama, Toru

2006-01-01

S. dysgalactiae-derived mitogen, a superantigen, was crystallized. Crystals diffract to 2.4 Å at a synchrotron-radiation source and belong to space group P3/P3 1 /P3 2 , with unit-cell parameters a = b = 52.7, c = 62.4 Å, γ = 120° and one molecule in the crystallographic asymmetric unit. Superantigens are bacterial or viral toxins with potent immunostimulatory properties. Streptococcus dysgalactiae-derived mitogen, a 25 kDa protein, is a recently discovered superantigen isolated from S. dysgalactiae culture supernatant. Sequence considerations suggest that it belongs to a new superantigen family distinct from other superantigens. The protein was expressed in Escherichia coli cells and purified to homogeneity. Crystals were grown at pH 4.2–4.4 in the presence of 18–20%(w/v) PEG 3350 and 0.4 M lithium nitrate. A complete data set to 2.4 Å resolution was collected from a single crystal at liquid-nitrogen temperatures using synchrotron radiation. The crystals belong to space group P3/P3 1 /P3 2 , with unit-cell parameters a = b = 52.7, c = 62.4 Å, γ = 120° and one molecule in the crystallographic asymmetric unit

Rainbow trapping in one-dimensional chirped photonic crystals composed of alternating dielectric slabs

International Nuclear Information System (INIS)

Shen, Yun; Fu, Jiwu; Yu, Guoping

2011-01-01

Highlights: → A simple one-dimensional chirped photonic crystal is proposed to realize rainbow trapping. → The results show different wavelengths can be trapped at different spatial positions. → The structure can be used for optical buffer, memories and filter, sorter, etc. -- Abstract: One-dimensional chirped photonic crystals composed of alternating dielectric slabs are proposed to realize rainbow trapping. We theoretically and numerically demonstrate that not only significantly reduced group velocity can be achieved in the proposed chirped structures, but different wavelengths can be localized in different spatial positions, indicating trapped rainbow. Our results imply a feasible way to slow or even trap light in simple systems, which can be used for optical buffer, memory, data processor and filter, sorter, etc.

Crystallization and preliminary X-ray analysis of stationary phase survival protein E (SurE) from Xylella fastidiosa in two crystal forms

International Nuclear Information System (INIS)

Reis, Marcelo Augusto dos; Saraiva, Antonio Marcos; Santos, Marcelo Leite dos; Souza, Anete Pereira de; Aparicio, Ricardo

2012-01-01

The crystallization and preliminary analysis of two crystal forms of survival protein E from X. fastidiosa are reported. The bacterium Xylella fastidiosa is a phytopathogenic organism that causes citrus variegated chlorosis, a disease which attacks economically important crops, mainly oranges. In this communication, the crystallization and preliminary X-ray crystallographic analysis of XfSurE, a survival protein E from X. fastidiosa, are reported. Data were collected for two crystal forms, I and II, to 1.93 and 2.9 Å resolution, respectively. Crystal form I belonged to space group C2, with unit-cell parameters a = 172.36, b = 84.18, c = 87.24 Å, α = γ = 90, β = 96.59°, whereas crystal form II belonged to space group C2, with unit-cell parameters a = 88.05, b = 81.26, c = 72.84 Å, α = γ = 90, β = 94.76°

Unified Digital Periodic Signal Filters for Power Converter Systems

DEFF Research Database (Denmark)

Yang, Yongheng; Xin, Zhen; Zhou, Keliang

2017-01-01

Periodic signal controllers like repetitive and resonant controllers have demonstrated much potential in the control of power electronic converters, where periodic signals (e.g., ac voltages and currents) can be precisely regulated to follow references. Beyond the control of periodic signals, ac...... signal processing (e.g., in synchronization and pre-filtering) is also very important for power converter systems. Hence, this paper serves to unify digital periodic signal filters so as to maximize their roles in power converter systems (e.g., enhance the control of ac signals). The unified digital...... periodic signal filters behave like a comb filter, but it can also be configured to selectively filter out the harmonics of interest (e.g., the odd-order harmonics in single-phase power converter systems). Moreover, a virtual variable-sampling-frequency unit delay that enables frequency adaptive periodic...

Specific filters applied in nuclear medicine services

Energy Technology Data Exchange (ETDEWEB)

Ramos, Vitor S.; Crispim, Verginia R., E-mail: verginia@con.ufrj.b [Coordenacao dos Programas de Pos-Graduacao de Engenharia (PEN/COPPE/UFRJ), RJ (Brazil). Programa de Engenharia Nuclear; Brandao, Luis E.B. [Instituto de Engenharia Nuclear (IEN/CNEN-RJ) Rio de Janeiro, RJ (Brazil)

2011-07-01

In Nuclear Medicine, radioiodine, in various chemical forms, is a key tracer used in diagnostic practices and/or therapy. Due to its high volatility, medical professionals may incorporate radioactive iodine during the preparation of the dose to be administered to the patient. In radioactive iodine therapy doses ranging from 3.7 to 7.4 GBq per patient are employed. Thus, aiming at reducing the risk of occupational contamination, we developed a low cost filter to be installed at the exit of the exhaust system where doses of radioactive iodine are fractionated, using domestic technology. The effectiveness of radioactive iodine retention by silver impregnated silica [10%] crystals and natural activated carbon was verified using radiotracer techniques. The results showed that natural activated carbon is effective for I{sub 2} capture for a large or small amount of substrate but its use is restricted due to its low flash point (150 deg C). Besides, when poisoned by organic solvents, this flash point may become lower, causing explosions if absorbing large amounts of nitrates. To hold the CH{sub 3}I gas, it was necessary to increase the volume of natural activated carbon since it was not absorbed by SiO{sub 2} + Ag crystals. We concluded that, for an exhaust flow range of (306 {+-} 4) m{sup 3}/h, a double stage filter using SiO{sub 2} + Ag in the first stage and natural activated carbon in the second is sufficient to meet radiological safety requirements. (author)

Development of methodology for characterization of cartridge filters from the IEA-R1 using the Monte Carlo method

International Nuclear Information System (INIS)

Costa, Priscila

2014-01-01

The Cuno filter is part of the water processing circuit of the IEA-R1 reactor and, when saturated, it is replaced and becomes a radioactive waste, which must be managed. In this work, the primary characterization of the Cuno filter of the IEA-R1 nuclear reactor at IPEN was carried out using gamma spectrometry associated with the Monte Carlo method. The gamma spectrometry was performed using a hyperpure germanium detector (HPGe). The germanium crystal represents the detection active volume of the HPGe detector, which has a region called dead layer or inactive layer. It has been reported in the literature a difference between the theoretical and experimental values when obtaining the efficiency curve of these detectors. In this study we used the MCNP-4C code to obtain the detector calibration efficiency for the geometry of the Cuno filter, and the influence of the dead layer and the effect of sum in cascade at the HPGe detector were studied. The correction of the dead layer values were made by varying the thickness and the radius of the germanium crystal. The detector has 75.83 cm 3 of active volume of detection, according to information provided by the manufacturer. Nevertheless, the results showed that the actual value of active volume is less than the one specified, where the dead layer represents 16% of the total volume of the crystal. A Cuno filter analysis by gamma spectrometry has enabled identifying energy peaks. Using these peaks, three radionuclides were identified in the filter: 108m Ag, 110m Ag and 60 Co. From the calibration efficiency obtained by the Monte Carlo method, the value of activity estimated for these radionuclides is in the order of MBq. (author)

Crystallization of the FaeE chaperone of Escherichia coli F4 fimbriae

International Nuclear Information System (INIS)

Van Molle, Inge; Buts, Lieven; Coppens, Fanny; Qiang, Liu; Wyns, Lode; Loris, Remy; Bouckaert, Julie; De Greve, Henri

2005-01-01

The periplasmic chaperone FaeE of E. coli F4 fimbriae crystallizes in three crystal forms. F4 (formerly K88) fimbriae from enterotoxigenic Escherichia coli are assembled via the FaeE/FaeD chaperone/usher pathway. The chaperone FaeE crystallizes in three crystal forms, all belonging to space group C2. Crystals of form 1 diffract to 2.3 Å and have unit-cell parameters a = 195.7, b = 78.5, c = 184.6 Å, β = 102.2°. X-ray data for crystal form 2 were collected to 2.7 Å using an SeMet variant of FaeE. The crystals have unit-cell parameters a = 136.4, b = 75.7, c = 69.4 Å, β = 92.8°. Crystals of form 3 were formed in a solution containing the FaeE–FaeG complex and diffract to 2.8 Å. Unit-cell parameters are a = 109.7, b = 78.6, c = 87.8 Å, β = 96.4°

Crystallization of the FaeE chaperone of Escherichia coli F4 fimbriae

Energy Technology Data Exchange (ETDEWEB)

Van Molle, Inge, E-mail: ivmolle@vub.ac.be; Buts, Lieven; Coppens, Fanny; Qiang, Liu; Wyns, Lode; Loris, Remy; Bouckaert, Julie; De Greve, Henri [Laboratorium voor Ultrastructuur, Vlaams Interuniversitair Instituut voor Biotechnologie, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussel (Belgium)

2005-04-01

The periplasmic chaperone FaeE of E. coli F4 fimbriae crystallizes in three crystal forms. F4 (formerly K88) fimbriae from enterotoxigenic Escherichia coli are assembled via the FaeE/FaeD chaperone/usher pathway. The chaperone FaeE crystallizes in three crystal forms, all belonging to space group C2. Crystals of form 1 diffract to 2.3 Å and have unit-cell parameters a = 195.7, b = 78.5, c = 184.6 Å, β = 102.2°. X-ray data for crystal form 2 were collected to 2.7 Å using an SeMet variant of FaeE. The crystals have unit-cell parameters a = 136.4, b = 75.7, c = 69.4 Å, β = 92.8°. Crystals of form 3 were formed in a solution containing the FaeE–FaeG complex and diffract to 2.8 Å. Unit-cell parameters are a = 109.7, b = 78.6, c = 87.8 Å, β = 96.4°.

Crystallization of purple nitrous oxide reductase from Pseudomonas stutzeri

International Nuclear Information System (INIS)

Pomowski, Anja; Zumft, Walter G.; Kroneck, Peter M. H.; Einsle, Oliver

2010-01-01

The physiologically active form of nitrous oxide reductase was isolated and crystallized under strict exclusion of dioxygen and diffraction data were collected from crystals belonging to two different space groups. Nitrous oxide reductase (N 2 OR) from Pseudomonas stutzeri catalyzes the final step in denitrification: the two-electron reduction of nitrous oxide to molecular dinitrogen. Crystals of the enzyme were grown under strict exclusion of dioxygen by sitting-drop vapour diffusion using 2R,3R-butanediol as a cryoprotectant. N 2 OR crystallized in either space group P1 or P6 5 . Interestingly, the key determinant for the resulting space group was the crystallization temperature. Crystals belonging to space group P1 contained four 130 kDa dimers in the asymmetric unit, while crystals belonging to space group P6 5 contained a single dimer in the asymmetric unit. Diffraction data were collected to resolutions better than 2 Å

Duty cycle dependence of a periodically poled LiNbO3-based electro-optic Solc filter.

Science.gov (United States)

Rabia, Eyal; Arie, Ady

2006-01-20

We demonstrate that the performance of a periodically poled LiNbO3- (PPLN-) based electro-optic Solc filter is dependent on the duty cycle of the crystal. This may limit the performance of the device for applications such as add-drop filtering and switching, owing to the deterioration of the extinction ratio. It is shown that by adding a retarder to the Solc filter it is possible to improve the extinction ratio; thus the dependence of the filter on the duty cycle can be reduced. Using Jones calculus, we analyzed the effect of a variable retarder that can also be rotated on the extinction ratio. We experimentally observed a 6 dB increase in the extinction ratio when we used a half-wavelength retarder.

Sensory Pollution from Bag Filters, Carbon Filters and Combinations

DEFF Research Database (Denmark)

Bekö, Gabriel; Clausen, Geo; Weschler, Charles J.

2008-01-01

by an upstream pre-filter (changed monthly), an EU7 filter protected by an upstream activated carbon (AC) filter, and EU7 filters with an AC filter either downstream or both upstream and downstream. In addition, two types of stand-alone combination filters were evaluated: a bag-type fiberglass filter...... that contained AC and a synthetic fiber cartridge filter that contained AC. Air that had passed through used filters was most acceptable for those sets in which an AC filter was used downstream of the particle filter. Comparable air quality was achieved with the stand-alone bag filter that contained AC...

Crystal structure of N-(quinolin-6-ylhydroxylamine

Directory of Open Access Journals (Sweden)

Anuruddha Rajapakse

2014-11-01

Full Text Available The title compound, C9H8N2O, crystallized with four independent molecules in the asymmetric unit. The four molecules are linked via one O—H...N and two N—H...N hydrogen bonds, forming a tetramer-like unit. In the crystal, molecules are further linked by O—H...N and N—H...O hydrogen bonds forming layers parallel to (001. These layers are linked via C—H...O hydrogen bonds and a number of weak C—H...π interactions, forming a three-dimensional structure. The crystal was refined as a non-merohedral twin with a minor twin component of 0.319.

FULL SCALE REGENERABLE HEPA FILTER DESIGN USING SINTERED METAL FILTER ELEMENTS

International Nuclear Information System (INIS)

Gil Ramos; Kenneth Rubow; Ronald Sekellick

2002-01-01

features in its design and operation. The element bundle would be an all welded assembly, which could be removed and replaced as a unit if the elements ever needed replacement. Each element had a spray nozzle mounted above it for cleaning; it could also be cleaned by a soak and backwash technique. The inlet nozzle incorporated a cyclonic separator to initially remove large suspended material and droplets. Tests indicated a significant reduction of dirt load getting to the filter elements, which would extend the operating time between cleanings. A high capacity blower was selected to overcome the higher pressure drop of the metallic elements. The blower, having a 25 horsepower motor, would be capable of operating the system to higher pressure drops than available on the glass fiber HEPA filters. This additional capacity further increases the operating duration of the filter. Upon successful testing and acceptance of the full-scale design, Phase IIB would involve the construction and test of a full-scale prototype system on an actual HLW tank. Phase IIA was completed but for funding and priority reasons the contract was halted; thus Phase IIB would not be pursued at this time. The Mott RHFS has been proven at each stage of the development process to meet the requirements of a suitable replacement system for the glass fiber HEPA filters enabling great cost savings. It remains to test a full-scale operating system on an actual high level waste tank to fully demonstrate the performance and anticipated cost savings of the Mott RHFS. Mott is confident that the performance will be more than acceptable

Fabrication of Ceramic Layer-by-Layer Infrared Wavelength Photonic Band Gap Crystals

Energy Technology Data Exchange (ETDEWEB)

Kang, Henry Hao-Chuan [Iowa State Univ., Ames, IA (United States)

2004-12-19

Photonic band gap (PBG) crystals, also known as photonic crystals, are periodic dielectric structures which form a photonic band gap that prohibit the propagation of electromagnetic (EM) waves of certain frequencies at any incident angles. Photonic crystals have several potential applications including zero-threshold semiconductor lasers, the inhibition of spontaneous emission, dielectric mirrors, and wavelength filters. If defect states are introduced in the crystals, light can be guided from one location to another or even a sharp bending of light in micron scale can be achieved. This generates the potential for optical waveguide and optical circuits, which will contribute to the improvement in the fiber-optic communications and the development of high-speed computers.

Plasmonic and Photonic Modes Excitation in Graphene on Silicon Photonic Crystal Membrane

DEFF Research Database (Denmark)

Andryieuski, Andrei; Gu, Tingyi; Hao, Yufeng

. Being deposited on a silicon photonic crystal membrane graphene serves as a highly promising system for modern optoelectronics with rich variety of possible regimes. Depending on the relation between the photonic crystal lattice constant and wavelengths (plasmonic, photonic and free-space) we identify...... characterization. Measured data are well correlated with the numerical analysis. Combined graphene – silicon photonic crystal membranes can find applications for infrared absorbers, modulators, filters, sensors and photodetectors....... four different interaction schemes. We refer to them as metamaterial, plasmonic, photonic and diffraction grating regimes based on the principle character of light interactions with the graphene deposited on the Si photonic crystal membrane. The optimal configurations for resonant excitation of modes...

A new look at the economic disposal of contaminated aerosol filters

International Nuclear Information System (INIS)

Sinhuber, D.; Stiehl, H.H.; Schroth, W.

1977-01-01

HEPA filter elements loaded with radioactive aerosols represent a large percentage of the radioactive waste of nuclear plants. The HEPA filter elements used at present in air filter units are not suitable to an economic disposal and space-saving final storage on account of their construction. New concepts for HEPA filters are necessary from the point of view of waste disposal. The criteria of these new designs are as follows: reduction of space required for HEPA filters used at the same or even increased flow rates and with the same efficiency; essentially smaller dimensions of HEPA filters for storage in waste containers; removal without contamination, volume reduction (without contamination) for disposal of the HEPA filters; smallest possible volume of the HEPA filters after processing for final storage. The construction of HEPA filters as a result of the requirements mentioned above and taking into consideration the present stage of technology is explained. The advantages of such construction with regard to the criteria mentioned before are presented in comparison with the HEPA filters at present in use

First principles crystal engineering of nonlinear optical materials. I. Prototypical case of urea

Science.gov (United States)

Masunov, Artëm E.; Tannu, Arman; Dyakov, Alexander A.; Matveeva, Anastasia D.; Freidzon, Alexandra Ya.; Odinokov, Alexey V.; Bagaturyants, Alexander A.

2017-06-01

The crystalline materials with nonlinear optical (NLO) properties are critically important for several technological applications, including nanophotonic and second harmonic generation devices. Urea is often considered to be a standard NLO material, due to the combination of non-centrosymmetric crystal packing and capacity for intramolecular charge transfer. Various approaches to crystal engineering of non-centrosymmetric molecular materials were reported in the literature. Here we propose using global lattice energy minimization to predict the crystal packing from the first principles. We developed a methodology that includes the following: (1) parameter derivation for polarizable force field AMOEBA; (2) local minimizations of crystal structures with these parameters, combined with the evolutionary algorithm for a global minimum search, implemented in program USPEX; (3) filtering out duplicate polymorphs produced; (4) reoptimization and final ranking based on density functional theory (DFT) with many-body dispersion (MBD) correction; and (5) prediction of the second-order susceptibility tensor by finite field approach. This methodology was applied to predict virtual urea polymorphs. After filtering based on packing similarity, only two distinct packing modes were predicted: one experimental and one hypothetical. DFT + MBD ranking established non-centrosymmetric crystal packing as the global minimum, in agreement with the experiment. Finite field approach was used to predict nonlinear susceptibility, and H-bonding was found to account for a 2.5-fold increase in molecular hyperpolarizability to the bulk value.

Neutron transmission and reflection at a copper single crystal

Energy Technology Data Exchange (ETDEWEB)

Adib, M.; Maayouf, R.M.A.; Abdel-Kawy, A.; Fayek, M.; Habib, N. (Atomic Energy Establishment, Cairo (Egypt). Reactor and Neutron Physics Dept.); Wahba, M. (Ain Shams Univ., Cairo (Egypt). Dept. of Engineering Physics and Mathematics)

1991-06-01

Neutron transmission and reflection at a copper single crystal cut along the (111) plane were studied with the fixed-scattering-angle spectrometer installed at the ET-RR-1 reactor. The transmission was measured for neutron wavelengths between 0.15 and 0.46 nm and various orientations of the (111) plane with respect to the incident beam. When used as a neutron band pass filter, the crystal is optimally oriented when the neutron beam is incident parallel to the (111) direction. The reflectivity was measured for the (111) plane at 45deg with respect to the incident beam. The results were found to be in reasonable agreement with a value predicted for the reflected intensity at an imperfect crystal with finite absorption. (orig.).

Neutron transmission and reflection at a copper single crystal

International Nuclear Information System (INIS)

Adib, M.; Maayouf, R.M.A.; Abdel-Kawy, A.; Fayek, M.; Habib, N.; Wahba, M.

1991-01-01

Neutron transmission and reflection at a copper single crystal cut along the (111) plane were studied with the fixed-scattering-angle spectrometer installed at the ET-RR-1 reactor. The transmission was measured for neutron wavelengths between 0.15 and 0.46 nm and various orientations of the (111) plane with respect to the incident beam. When used as a neutron band pass filter, the crystal is optimally oriented when the neutron beam is incident parallel to the [111] direction. The reflectivity was measured for the (111) plane at 45deg with respect to the incident beam. The results were found to be in reasonable agreement with a value predicted for the reflected intensity at an imperfect crystal with finite absorption. (orig.) [de

Topological Valley Transport in Two-dimensional Honeycomb Photonic Crystals.

Science.gov (United States)

Yang, Yuting; Jiang, Hua; Hang, Zhi Hong

2018-01-25

Two-dimensional photonic crystals, in analogy to AB/BA stacking bilayer graphene in electronic system, are studied. Inequivalent valleys in the momentum space for photons can be manipulated by simply engineering diameters of cylinders in a honeycomb lattice. The inequivalent valleys in photonic crystal are selectively excited by a designed optical chiral source and bulk valley polarizations are visualized. Unidirectional valley interface states are proved to exist on a domain wall connecting two photonic crystals with different valley Chern numbers. With the similar optical vortex index, interface states can couple with bulk valley polarizations and thus valley filter and valley coupler can be designed. Our simple dielectric PC scheme can help to exploit the valley degree of freedom for future optical devices.

Crystallization and preliminary characterization of three different crystal forms of human saposin C heterologously expressed in Pichia pastoris

International Nuclear Information System (INIS)

Schultz-Heienbrok, Robert; Remmel, Natascha; Klingenstein, R.; Rossocha, Maksim; Sandhoff, Konrad; Saenger, Wolfram; Maier, Timm

2006-01-01

Three different crystal forms were obtained of human saposin C. The structures could not be determined by molecular replacement using known solution structures of the protein as search models, supporting the notion of a highly flexible protein. The amphiphilic saposin proteins (A, B, C and D) act at the lipid–water interface in lysosomes, mediating the hydrolysis of membrane building blocks by water-soluble exohydrolases. Human saposin C activates glucocerebrosidase and β-galactosylceramidase. The protein has been expressed in Pichia pastoris, purified and crystallized in three different crystal forms, diffracting to a maximum resolution of 2.5 Å. Hexagonal crystals grew from 2-propanol-containing solution and contain a single molecule in the asymmetric unit according to the Matthews coefficient. Orthorhombic and tetragonal crystals were both obtained with pentaerythritol ethoxylate and are predicted to contain two molecules in the asymmetric unit. Attempts to determine the respective crystal structures by molecular replacement using either the known NMR structure of human saposin C or a related crystal structure as search models have so far failed. The failure of the molecular-replacement method is attributed to conformational changes of the protein, which are known to be required for its biological activity. Crystal structures of human saposin C therefore might be the key to mapping out the conformational trajectory of saposin-like proteins

Frequency shift of a crystal quartz resonator in thickness-shear modes induced by an array of hemispherical material units.

Science.gov (United States)

Yuantai Hu; Huiliang Hu; Bin Luo; Huan Xue; Jiemin Xie; Ji Wang

2013-08-01

A two-dimensional model was established to study the dynamic characteristics of a quartz crystal resonator with the upper surface covered by an array of hemispherical material units. A frequency-dependent equivalent mass ratio was proposed to simulate the effect of the covered units on frequency shift of the resonator system. It was found that the equivalent mass ratio alternately becomes positive or negative with change of shear modulus and radius of each material unit, which indicates that the equivalent mass ratio is strongly related to the vibration mode of the covered loadings. The further numerical results show the cyclical feature in the relationship of frequency shift and shear modulus/radius as expected. The solutions are useful in the analysis of frequency stability of quartz resonators and acoustic wave sensors.

A high-speed data-collection system for large-unit-cell crystals using an imaging plate as a detector

International Nuclear Information System (INIS)

Sato, Mamoru; Yamamoto, Masaki; Imada, Katsumi; Katsube, Yukiteru; Tanaka, Nobuo; Higashi, Tsuneyuki

1992-01-01

A high-speed data-collection system for large-unit-cell crystals is presented, using the Fuji Imaging Plate as an X-ray detector and a rotating-anode generator as the X-ray source. It is an automatic data-acquisition system that requires almost no manual intervention. The quality of data collected on the system is discussed. Merging R values ranged from 0.04 to 0.05. Compared with a four-circle diffractometer, data reproducibility was better, isomorphous/anomalous Patterson maps were almost identical in quality and data from a small-molecule crystal, cytidine, were of almost the same quality. Protein structures were refinable using the data measured on the system, the final crystallographic R value of the 2.2 A 3-isopropylmalate dehydrogenase structure being 0.185 and that of the 1.88 A Flammulina veltipes agglutinin structure being 0.199. (orig.)

Expression, purification and crystallization of Helicobacter pyloril-asparaginase

Energy Technology Data Exchange (ETDEWEB)

Dhavala, Prathusha [Turku Centre for Biotechnology, University of Turku and Åbo Akademi, Turku 20521 (Finland); Krasotkina, Julya [Institute for Biomedical Sciences, Russian Academy of Medical Sciences, Moscow (Russian Federation); Dubreuil, Christine; Papageorgiou, Anastassios C., E-mail: tassos.papageorgiou@btk.fi [Turku Centre for Biotechnology, University of Turku and Åbo Akademi, Turku 20521 (Finland)

2008-08-01

l-Asparaginase from H. pylori was overexpressed in E. coli, purified and crystallized. The crystals belonged to space group I222, with unit-cell parameters a = 63.6, b = 94.9, c = 100.2 Å and one molecule in the asymmetric unit. A complete data set to 1.6 Å resolution was collected using synchrotron radiation. The l-asparaginases from Escherichia coli and Erwinia chrysanthemi are effective drugs that have been used in the treatment of acute childhood lymphoblastic leukaemia for over 30 years. However, despite their therapeutic potential, they can cause serious side effects as a consequence of their intrinsic glutaminase activity, which leads to l-glutamine depletion in the blood. Consequently, new asparaginases with low glutaminase activity, fewer side effects and high activity towards l-asparagine are highly desirable as better alternatives in cancer therapy. l-Asparaginase from Helicobacter pylori was overexpressed in E. coli and purified for structural studies. The enzyme was crystallized at pH 7.0 in the presence of 16–19%(w/v) PEG 4000 and 0.1 M magnesium formate. Data were collected to 1.6 Å resolution at 100 K from a single crystal at a synchrotron-radiation source. The crystals belong to space group I222, with unit-cell parameters a = 63.6, b = 94.9, c = 100.2 Å and one molecule of l-asparaginase in the asymmetric unit. Elucidation of the crystal structure will provide insight into the active site of the enzyme and a better understanding of the structure–activity relationship in l-asparaginases.

Vena Cava Filter Retrieval with Aorto-Iliac Arterial Strut Penetration.

Science.gov (United States)

Holly, Brian P; Gaba, Ron C; Lessne, Mark L; Lewandowski, Robert J; Ryu, Robert K; Desai, Kush R; Sing, Ronald F

2018-05-03

To evaluate the safety and technical success of inferior vena cava (IVC) filter retrieval in the setting of aorto-iliac arterial strut penetration. IVC filter registries from six large United States IVC filter retrieval practices were retrospectively reviewed to identify patients who underwent IVC filter retrieval in the setting of filter strut penetration into the adjacent aorta or iliac artery. Patient demographics, implant duration, indication for placement, IVC filter type, retrieval technique and technical success, adverse events, and post procedural clinical outcomes were identified. Arterial penetration was determined based on pre-procedure CT imaging in all cases. The IVC filter retrieval technique used was at the discretion of the operating physician. Seventeen patients from six US centers who underwent retrieval of an IVC filter with at least one strut penetrating either the aorta or iliac artery were identified. Retrieval technical success rate was 100% (17/17), without any major adverse events. Post-retrieval follow-up ranging from 10 days to 2 years (mean 4.6 months) was available in 12/17 (71%) patients; no delayed adverse events were encountered. Findings from this series suggest that chronically indwelling IVC filters with aorto-iliac arterial strut penetration may be safely retrieved.

Expression, purification and crystallization of Streptococcus dysgalactiae-derived mitogen

Energy Technology Data Exchange (ETDEWEB)

Papageorgiou, Anastassios C., E-mail: tassos.papageorgiou@btk.fi; Saarinen, Susanna; Ramirez-Bartutis, Rosa [Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, Turku 20521 (Finland); Kato, Hidehito; Uchiyama, Takehiko [Department of Microbiology and Immunology, Tokyo Women’s Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo 162-8666 (Japan); Kirikae, Teruo; Miyoshi-Akiyama, Toru [Department of Infectious Diseases, International Medical Center of Japan, 1-21-1 Toyama, Shinjuku-ku, Tokyo 162-8655 (Japan); Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, Turku 20521 (Finland)

2006-03-01

S. dysgalactiae-derived mitogen, a superantigen, was crystallized. Crystals diffract to 2.4 Å at a synchrotron-radiation source and belong to space group P3/P3{sub 1}/P3{sub 2}, with unit-cell parameters a = b = 52.7, c = 62.4 Å, γ = 120° and one molecule in the crystallographic asymmetric unit. Superantigens are bacterial or viral toxins with potent immunostimulatory properties. Streptococcus dysgalactiae-derived mitogen, a 25 kDa protein, is a recently discovered superantigen isolated from S. dysgalactiae culture supernatant. Sequence considerations suggest that it belongs to a new superantigen family distinct from other superantigens. The protein was expressed in Escherichia coli cells and purified to homogeneity. Crystals were grown at pH 4.2–4.4 in the presence of 18–20%(w/v) PEG 3350 and 0.4 M lithium nitrate. A complete data set to 2.4 Å resolution was collected from a single crystal at liquid-nitrogen temperatures using synchrotron radiation. The crystals belong to space group P3/P3{sub 1}/P3{sub 2}, with unit-cell parameters a = b = 52.7, c = 62.4 Å, γ = 120° and one molecule in the crystallographic asymmetric unit.

Crystal structure and spin state of mixed-crystals of iron with NCS and NCBH3 for the assembled complexes bridged by 1,3-bis(4-pyridyl)propanes

International Nuclear Information System (INIS)

Haruka Dote; Hiroki Yasuhara

2015-01-01

New mixed crystals, Fe(NCS) x (NCBH 3 )( 2-x )(bpp) 2 , (bpp = 1,3-bis(4-pyridyl)propane) were synthesized. The formation of mixed crystals was confirmed by powder X-ray diffraction patterns and single crystal X-ray structural analysis. Elemental analyses showed that all Fe(NCS) x (NCBH 3 )( 2-x )(bpp) 2 samples had more Fe(NCS) 2 unit than the preparation fraction. 57 Fe Moessbauer spectroscopy revealed that all the spectra consist of only Fe(NCS) 2 unit and Fe(NCBH 3 ) 2 unit. And the fraction of low-spin state in the Fe(NCBH 3 ) 2 unit changed with the change of x. The results suggested that the high spin site of Fe(NCS) 2 unit affects the spin state of Fe(NCBH 3 ) 2 unit. (author)

The medline UK filter: development and validation of a geographic search filter to retrieve research about the UK from OVID medline.

Science.gov (United States)

Ayiku, Lynda; Levay, Paul; Hudson, Tom; Craven, Jenny; Barrett, Elizabeth; Finnegan, Amy; Adams, Rachel

2017-07-13

A validated geographic search filter for the retrieval of research about the United Kingdom (UK) from bibliographic databases had not previously been published. To develop and validate a geographic search filter to retrieve research about the UK from OVID medline with high recall and precision. Three gold standard sets of references were generated using the relative recall method. The sets contained references to studies about the UK which had informed National Institute for Health and Care Excellence (NICE) guidance. The first and second sets were used to develop and refine the medline UK filter. The third set was used to validate the filter. Recall, precision and number-needed-to-read (NNR) were calculated using a case study. The validated medline UK filter demonstrated 87.6% relative recall against the third gold standard set. In the case study, the medline UK filter demonstrated 100% recall, 11.4% precision and a NNR of nine. A validated geographic search filter to retrieve research about the UK with high recall and precision has been developed. The medline UK filter can be applied to systematic literature searches in OVID medline for topics with a UK focus. © 2017 Crown copyright. Health Information and Libraries Journal © 2017 Health Libraries GroupThis article is published with the permission of the Controller of HMSO and the Queen's Printer for Scotland.

Modified septic tank-anaerobic filter unit as a two-stage onsite domestic wastewater treatment system.

Science.gov (United States)

Sharma, Meena Kumari; Khursheed, Anwar; Kazmi, Absar Ahmad

2014-01-01

This study demonstrates the performance evaluation of a uniquely designed two-stage system for onsite treatment of domestic wastewater. The system consisted of two upflow anaerobic bioreactors, a modified septic tank followed by an upflow anaerobic filter, accommodated within a single cylindrical unit. The system was started up without inoculation at 24 h hydraulic retention time (HRT). It achieved a steady-state condition after 120 days. The system was observed to be remarkably efficient in removing pollutants during steady-state condition with the average removal efficiency of 88.6 +/- 3.7% for chemical oxygen demand, 86.3 +/- 4.9% for biochemical oxygen demand and 91.2 +/- 9.7% for total suspended solids. The microbial analysis revealed a high reduction (>90%) capacity of the system for indicator organism and pathogens. It also showed a very good endurance against imposed hydraulic shock load. Tracer study showed that the flow pattern was close to plug flow reactor. Mean HRT was also found to be close to the designed value.

Crystallization and preliminary X-ray analysis of vicenisaminyltransferase VinC

International Nuclear Information System (INIS)

Nango, Eriko; Minami, Atsushi; Kumasaka, Takashi; Eguchi, Tadashi

2008-01-01

The crystallization of VinC, a glycosyltransferase involved in the biosynthesis of the antitumour antibiotic vicenistatin, is reported. A recombinant glycosyltransferase, VinC, from Streptomyces halstedii HC34 has been crystallized at 293 K using PEG 3350 as precipitant. The diffraction pattern of the crystal extends to 2.0 Å resolution at 100 K using synchrotron radiation at SPring-8. The crystals are orthorhombic and belong to space group I222, with unit-cell parameters a = 98.21, b = 130.39, c = 140.11 Å. The presence of two molecules per asymmetric unit gives a crystal volume per protein weight (V M ) of 2.43 Å 3 Da −1 and a solvent content of 49.5% by volume

Crystal structures of titanium–aluminium and –gallium complexes bearing two μ2-CH3 units

Directory of Open Access Journals (Sweden)

Tim Oswald

2017-05-01

Full Text Available The isotypic crystal structures of two titanocene complexes containing an EMe3 unit (E = Al, Ga; Me = methyl with two μ2-coordinating methyl groups, namely [μ-1(η5-(adamantan-1-yl-2κC1cycylopentadienyl]di-μ2-methyl-methyl-2κC-[1(η5-pentamethylcyclopentadienyl]aluminiumtitanium(III, [AlTi(CH33(C10H15(C15H18], and [μ-1(η5-(adamantan-1-yl-2κC1cycylopentadienyl]di-μ2-methyl-methyl-2κC-[1(η5-pentamethylcyclopentadienyl]galliumtitanium(III, [GaTi(CH33(C10H15(C15H18], are reported. Reacting a dinuclear nitrogen-bridged low-valent titanium(III complex with the Lewis acids AlMe3 or GaMe3 results in the loss of molecular dinitrogen and the formation of two monomeric titanocene(III fragments bearing two μ2-bridging methyl groups. Single crystal X-ray diffraction reveals the formation of a new E—C bond involving the pentafulvene ligand while the bridging and terminal methyl groups remain intact.

Miniaturized and Ferrite Based Tunable Bandpass Filters in LCP and LTCC Technologies for SoP Applications

KAUST Repository

Arabi, Eyad A.

2015-01-01

, namely low temperature co-fired ceramic (LTCC) and the liquid crystal polymers (LCP) is demonstrated. The miniaturized filter is based on a second order topology, which has been modified to improve the selectivity and out-of-band rejection without

Formation and growth mechanism of TiC crystal in TiCp/Ti composites

Institute of Scientific and Technical Information of China (English)

金云学; 王宏伟; 曾松岩; 张二林

2002-01-01

Ti-C and Ti-Al-C alloys were prepared using gravity and directional solidification processes. Morphologies of TiC crystal were investigated by using SEM, XRD and EDX. Also, the formation and growth mechanism of TiC crystal have been analyzed on the basis of coordination polyhedron growth unit theory. During solidification of titanium alloys, the coordination polyhedron growth unit is TiC6. TiC6 growth units stack in a linking mode of edge to edge and form octahedral TiC crystal with {111} planes as present faces. Although the growing geometry of TiC crystal is decided by its lattice structure, the final morphology of TiC crystal depends on the effects of its growth environment. In solute concentration distribution, the super-saturation of C or TiC6 at the corners of octahedral TiC crystal is much higher than that of edges and faces of octahedral TiC crystal. At these corners the driving force for crystal growth is greater and the interface is instable which contribute to quick stacking rate of growth units at these corners and result in secondary dendrite arms along TiC crystallographic 〈100〉 directions. TiC crystal finally grows to be dendrites.

Liquid crystal dimers

CERN Document Server

Kumar Pal, Santanu

2017-01-01

This book covers in-depth discussion of design principles, synthesis and thermal behavior of all types of liquid crystal (LC) dimers. The text presents recent advances in the field of LC dimers consisting of different mesogenic units such as calamitic, discotic and bent-core molecules. It starts with a chapter on the introduction of liquid crystal dimers, including their odd-even behavior, basic classification of dimers and common mesophases in dimers. The text shows how the molecular architectures are being used to develop new materials to study a range of interesting phenomena such as the biaxial nematic phase containing rod-like and disc-like mesogenic units. Finally, the text presents perspectives related to technological relevance of these dimers such as dopants in LC display mixtures exhibiting faster relaxation time, strong flexoelectric coupling and others to effect control over the properties of these materials.

Thermo-, photo-, and mechano-responsive liquid crystal networks enable tunable photonic crystals.

Science.gov (United States)

Akamatsu, N; Hisano, K; Tatsumi, R; Aizawa, M; Barrett, C J; Shishido, A

2017-10-25

Tunable photonic crystals exhibiting optical properties that respond reversibly to external stimuli have been developed using liquid crystal networks (LCNs) and liquid crystal elastomers (LCEs). These tunable photonic crystals possess an inverse opal structure and are photo-responsive, but circumvent the usual requirement to contain dye molecules in the structure that often limit their applicability and cause optical degradation. Herein, we report tunable photonic crystal films that reversibly tune the reflection peak wavelength under thermo-, photo- and mechano-stimuli, through bilayering a stimuli-responsive LCN including azobenzene units with a colourless inverse opal film composed of non-responsive, flexible durable polymers. By mechanically deforming the azobenzene containing LCN via various stimuli, the reflection peak wavelength from the bilayered film assembly could be shifted on demand. We confirm that the reflection peak shift occurs due to the deformation of the stimuli-responsive layer propagating towards and into the inverse opal layer to change its shape in response, and this shift behaviour is repeatable without optical degradation.

Aquatic Plant/microbial Filters for Treating Septic Tank Effluent

Science.gov (United States)

Wolverton, B. C.

1988-01-01

The use of natural biological processes for treating many types of wastewater have been developed by NASA at the John C. Stennis Space Center, NSTL, Mississippi, during the past 15 years. The simplest form of this technology involves the use of aquatic plant/marsh filters for treatment of septic tank effluent. Septic tank effluent from single home units can be treated to advanced secondary levels and beyond by using a 37.2 sq m (400 sq ft) surface area washed gravel filter. This filter is generally 0.3 m (1 ft) deep with a surface cover of approximately 0.15 m (6 in.) of gravel. The plants in this filter are usually aesthetic or ornamental such as calla lily (Zantedeschia aethiopica), canna lily (Canna flaccida), elephant ear (Colocasia esculenta), and water iris (Iris pseudacorus).

Photonic and Plasmonic Guided Modes in Graphene-Silicon Photonic Crystals

DEFF Research Database (Denmark)

Gu, Tingyi; Andryieuski, Andrei; Hao, Yufeng

2015-01-01

We report the results of systematic studies of plasmonic and photonic guided modes in large-area single-layer graphene integrated into a nanostructured silicon substrate. The interaction of light with graphene and substrate photonic crystals can be classified in distinct regimes depending......, filters, sensors, and photodetectors utilizing silicon photonic platforms....... on the relation of the photonic crystal lattice constant and the relevant modal wavelengths, that is, plasmonic, photonic, and free-space. By optimizing the design of the substrate, these resonant modes can increase the absorption of graphene in the infrared, facilitating enhanced performance of modulators...

Study of the efficiency of some water treatment unit that present in houses in Erbil city-Iraq

Science.gov (United States)

Toma, Janan. Jabbar.; Hanna, Aveen. Matti.

2017-09-01

Many people in Erbil city started more than two decade to put special treatment units in their houses to purified water to become safer for drinking uses. The aim of this study was determine the efficiency of six kind water treatment units which include (two replicate of Crystal Water Purifier, So-Safe Water Filter, R O Water Purifier, Kontec Water Purified and Al-Kawther Purified Water). Water samples were collected in two sites one before and other after treatment unit. Each sample was collect with three replication during May to October-2016. Analyzed for Major cations concentration (calcium, magnesium, sodium and potassium), anions concentration (nitrate and chloride) and hydrogen ion concentration (pH), electrical conductivity (EC), total dissolved solids (TDS), alkalinity and total hardness by using standard methods. The water quality index values for all raw water sample befor and after treatment was good and excellent respectively for drinking purposes. Efficiency of So-Safe Water Filter was 66.32% it means was more efficiency than others special water treatment units while in RO Water Purifier was 27.14%, means less efficiency than other water purifier water under this study. Values for major cations, anions and others chemicals characteristics in the water samples after treatment became lower concentrations than befor treatment, likely an indication that these were removed by treatment. According to guideline of world health organization all of variables except total hardness befor treatment are safe and suitable for drinking purposes.

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.

Production, purification, crystallization and structure determination of H-1 Parvovirus

International Nuclear Information System (INIS)

Halder, Sujata; Nam, Hyun-Joo; Govindasamy, Lakshmanan; Vogel, Michèle; Dinsart, Christiane; Salomé, Nathalie; McKenna, Robert; Agbandje-McKenna, Mavis

2012-01-01

The production, purification, crystallization and crystallographic analysis of H-1 Parvovirus, a gene-therapy vector, are reported. Crystals of H-1 Parvovirus (H-1PV), an antitumor gene-delivery vector, were obtained for DNA-containing capsids and diffracted X-rays to 2.7 Å resolution using synchrotron radiation. The crystals belonged to the monoclinic space group P2 1 , with unit-cell parameters a = 255.4, b = 350.4, c = 271.6 Å, β = 90.34°. The unit cell contained two capsids, with one capsid per crystallographic asymmetric unit. The H-1PV structure has been determined by molecular replacement and is currently being refined

Continuous vacuum processing system for quartz crystal resonators

International Nuclear Information System (INIS)

Ney, R.J.; Hafner, E.

1979-01-01

An ultrahigh vacuum continuous cycle quartz crystal fabrication facility has been developed that assures an essentially contamination-free environment throughout the final manufacturing steps of the crystal unit. The system consists of five essentially tubular vacuum chambers that are interconnected through gate valves. The unplated crystal resonators, mounted in ceramic flatback frames and loaded on carrier trays, enter the vacuum system through an entrance air lock, are UV/ozone cleaned, baked at 300 0 C, plated to frequency, thermocompression sealed, and exit as completed crystal units through an exit air lock, while the bake, plate and seal chambers remain under continuous vacuum permanently. In-line conveyor belts are used, in conjunction with balanced vacuum manipulators, to move the resonator components to the various work stations. Unique high density, highly directional nozzle beam evaporation sources, capable of long term operation without reloading, are used for electroding the resonators simultaneously on both sides. The design goal for the system is a production rate of 200 units per 8 hour day; it is adaptable to automatic operation

Fir Filters Compliant with the IEEE Standard for M Class PMU

Directory of Open Access Journals (Sweden)

Duda Krzysztof

2016-12-01

Full Text Available In this paper it is shown that M class PMU (Phasor Measurement Unit reference model for phasor estimation recommended by the IEEE Standard C37.118.1 with the Amendment 1 is not compliant with the Standard. The reference filter preserves only the limits for TVE (total vector error, and exceeds FE (frequency error and RFE (rate of frequency error limits. As a remedy we propose new filters for phasor estimation for M class PMU that are fully compliant with the Standard requirements. The proposed filters are designed: 1 by the window method; 2 as flat-top windows; or as 3 optimal min-max filters. The results for all Standard compliance tests are presented, confirming good performance of the proposed filters. The proposed filters are fixed at the nominal frequency, i.e. frequency tracking and adaptive filter tuning are not required, therefore they are well suited for application in lowcost popular PMUs.

Time-Sequential Working Wavelength-Selective Filter for Flat Autostereoscopic Displays

Directory of Open Access Journals (Sweden)

René de la Barré

2017-02-01

Full Text Available A time-sequential working, spatially-multiplexed autostereoscopic 3D display design consisting of a fast switchable RGB-color filter array and a fast color display is presented. The newly-introduced 3D display design is usable as a multi-user display, as well as a single-user system. The wavelength-selective filter barrier emits the light from a larger aperture than common autostereoscopic barrier displays with similar barrier pitch and ascent. Measurements on a demonstrator with commercial display components, simulations and computational evaluations have been carried out to describe the proposed wavelength-selective display design in static states and to show the weak spots of display filters in commercial displays. An optical modelling of wavelength-selective barriers has been used for instance to calculate the light ray distribution properties of that arrangement. In the time-sequential implementation, it is important to avoid that quick eye or eyelid movement leads to visible color artifacts. Therefore, color filter cells, switching faster than conventional LC display cells, must distribute directed light from different primaries at the same time, to create a 3D presentation. For that, electric tunable liquid crystal Fabry–Pérot color filters are presented. They switch on-off the colors red, green and blue in the millisecond regime. Their active areas consist of a sub-micrometer-thick nematic layer sandwiched between dielectric mirrors and indium tin oxide (ITO-electrodes. These cells shall switch narrowband light of red, green or blue. A barrier filter array for a high resolution, glasses-free 3D display has to be equipped with several thousand switchable filter elements having different color apertures.

Crystallization and preliminary X-ray crystallographic analysis of a new crystal form of hydroxylamine oxidoreductase from Nitrosomonas europaea

International Nuclear Information System (INIS)

Cedervall, Peder E.; Hooper, Alan B.; Wilmot, Carrie M.

2009-01-01

A new crystal form of N. europaea hydroxylamine oxidoreductase (space group P2 1 2 1 2) diffracted to 2.25 Å resolution at a third-generation synchrotron X-ray source. Hydroxylamine oxidoreductase (HAO) from Nitrosomonas europaea is a homotrimeric protein that catalyzes the oxidation of hydroxylamine to nitrite. Each monomer, with a molecular weight of 67.1 kDa, contains seven c-type hemes and one heme P460, the porphyrin ring of which is covalently linked to a tyrosine residue from an adjacent subunit. HAO was first crystallized and structurally characterized at a resolution of 2.8 Å in 1997. The structure was solved in space group P6 3 and suffered from merohedral twinning. Here, a crystallization procedure is presented that yielded untwinned crystals belonging to space group P2 1 2 1 2, which diffracted to 2.25 Å resolution and contained one trimer in the asymmetric unit. The unit-cell parameters were a = 140.7, b = 142.6, c = 107.4 Å

Molecular mechanisms of crystal growth

International Nuclear Information System (INIS)

Pina, C. M.

2000-01-01

In this paper I present an example of the research that the Mineral Surface Group of the Munster University is conducting in the field of Crystal Growth. Atomic Force Microscopy (Am) in situ observations of different barite (BaSO4) faces growing from aqueous solutions, in combination with computer simulations of the surface attachment of growth units allows us to test crystal growth models. Our results demonstrate the strong structural control that a crystal can exert on its own growth, revealing also the limitation of the classical crystal growth theories (two dimensional nucleation and spiral growth models) in providing a complete explanation for the growth behaviour at a molecular scale. (Author) 6 refs

Pyrolytic Graphite as a Tunable Second order Neutron Filter

International Nuclear Information System (INIS)

Adib, M.

2009-01-01

A study has been carried out on the neutron transmission through pyrolytic graphite (PG) crystals in order to check its applicability as an efficient tunable second order neutron filter. The neutron transmission have been calculated as a function of neutron wavelengths in the range from 0.01 nm up to 0.7 nm at various PG mosaic spread, thickness and orientation of its c-axis with respect to the beam direction The Computer package Graphite has been used to provide the required calculation. It was shown that highly aligned (10 FWHM on mosaic spread) PG crystal ∼2 cm thick, may be tuned for optimum scattering of 2 second order neutrons within some favorable wavelength intervals in the range between 0.112 and 0.425 nm by adjusting the crystal in an appropriate orientation. .However, a less quality and thinner PG was found to almost eliminate 2 second order neutrons at only tuned values of wavelength corresponding to the poison of the triple intersection points of the curves (hkl) ± and (00l)

Nonlinear Filtering and Approximation Techniques

Science.gov (United States)

1991-09-01

filtering. UNIT8 Q RECERCE**No 1223 Programme 5 A utomatique, Productique, Traitement dui Signal et des Donnc~es CONSISTENT PARAMETER ESTIMATION FOR...ue’e[71 E C 2.’(Rm x [0,7]; R) is the unique solution of the Hamilton-Jacobi-Bellman equation 9u,’[7](x, t) - EAu "’[ 7](x,t) + He,’[ 7](x,t,Du,[ 7](x,t

Slow neutron total cross-section, transmission and reflection calculation for poly- and mono-NaCl and PbF2 crystals

Science.gov (United States)

Mansy, Muhammad S.; Adib, M.; Habib, N.; Bashter, I. I.; Morcos, H. N.; El-Mesiry, M. S.

2016-10-01

A detailed study about the calculation of total neutron cross-section, transmission and reflection from crystalline materials was performed. The developed computer code is approved to be sufficient for the required calculations, also an excellent agreement has been shown when comparing the code results with the other calculated and measured values. The optimal monochromator and filter parameters were discussed in terms of crystal orientation, mosaic spread, and thickness. Calculations show that 30 cm thick of PbF2 poly-crystal is an excellent cold neutron filter producing neutron wavelengths longer than 0.66 nm needed for the investigation of magnetic structure experiments. While mono-crystal filter PbF2 cut along its (1 1 1), having mosaic spread (η = 0.5°) and thickness 10 cm can only transmit thermal neutrons of the desired wavelengths and suppress epithermal and γ-rays forming unwanted background, when it is cooled to liquid nitrogen temperature. NaCl (2 0 0) and PbF2 (1 1 1) monochromator crystals having mosaic spread (η = 0.5°) and thickness 10 mm shows high neutron reflectivity for neutron wavelengths (λ = 0.114 nm and λ = 0.43 nm) when they used as a thermal and cold neutron monochromators respectively with very low contamination from higher order reflections.

Digital Simulation of a Hybrid Active Filter - An Active Filter in Series with a Shunt Passive Filter

OpenAIRE

Sitaram, Mahesh I; Padiyar, KR; Ramanarayanan, V

1998-01-01

Active filters have long been in use for the filtering of power system load harmonics. In this paper, the digital simulation results of a hybrid active power filter system for a rectifier load are presented. The active filter is used for filtering higher order harmonics as the dominant harmonics are filtered by the passive filter. This reduces the rating of the active filter significantly. The DC capacitor voltage of the active filter is controlled using a PI controller.

A single point mutation changes the crystallization behavior of Mycoplasma arthritidis-derived mitogen

Energy Technology Data Exchange (ETDEWEB)

Guo, Yi; Li, Zhong; Van Vranken, Sandra J. [Wadsworth Center, New York State Department of Health, Empire State Plaza, PO Box 509, Albany, New York 12201-0509 (United States); Li, Hongmin, E-mail: lih@wadsworth.org [Wadsworth Center, New York State Department of Health, Empire State Plaza, PO Box 509, Albany, New York 12201-0509 (United States); Department of Biomedical Sciences, School of Public Health, University at Albany, State University of New York, Empire State Plaza, PO Box 509, Albany, New York 12201-0509 (United States)

2006-03-01

The mutagenesis, crystallization and preliminary crystallographic analysis of M. arthritidis-derived mitogen is described. Mycoplasma arthritidis-derived mitogen (MAM) functions as a conventional superantigen (SAg). Although recombinant MAM has been crystallized by the hanging-drop vapour-diffusion method, the crystals diffracted poorly to only 5.0 Å resolution, with large unit-cell parameters a = 163.8, b = 93.0, c = 210.9 Å, β = 93.7° in the monoclinic space group P2{sub 1}. Unit-cell content analysis revealed that as many as 24 molecules could be present in the asymmetric unit. Systematic alanine mutagenesis was applied in order to search for mutants that give crystals of better quality. Two mutants, L50A and K201A, were crystallized under the same conditions as wild-type MAM (MAM{sub wt}). Crystals of the L50A mutant are isomorphous with those of MAM{sub wt}, while a new crystal form was obtained for the K201 mutant, belonging to the cubic space group P4{sub 1}32 with unit-cell parameters a = b = c = 181.9 Å. Diffraction data were collected to 3.6 and 2.8 Å resolution from crystals of the MAM L50A and K201A mutants, respectively. Molecular-replacement calculations suggest the presence of two molecules in the asymmetric unit for the MAM K201A mutant crystal, resulting in a V{sub M} of 5.0 Å Da{sup −1} and a solvent content of 75%. An interpretable electron-density map for the MAM K201A mutant crystal was produced using the molecular-replacement method.

Four crystal forms of a Bence-Jones protein

International Nuclear Information System (INIS)

Makino, Debora L.; Henschen-Edman, Agnes H.; McPherson, Alexander

2004-01-01

Four crystal forms have been grown and characterized by X-ray diffraction of a Bence-Jones protein collected from the urine of a multiple myeloma patient more than 40 y ago. The trigonal crystal form may shed some light on the formation of fibrils common to certain storage diseases. Four crystal forms have been grown and characterized by X-ray diffraction of a Bence-Jones protein collected from the urine of a multiple myeloma patient more than 40 years ago. Closely related tetragonal and orthorhombic forms belonging to space groups P4 3 2 1 2 and P2 1 2 1 2 1 , with unit-cell parameters a = b = 68.7, c = 182.1 and a = 67.7, b = 69.4, c = 87.3 Å, diffract to 1.5 and 1.9 Å, respectively. Two closely related trigonal forms, both belonging to space group P3 1 21 with unit-cell parameters a = b = 154.3 Å but differing by a doubling of the c axis, one 46.9 Å and the other 94.0 Å, diffract to 2.9 and 2.6 Å resolution, respectively. The trigonal crystal of short c-axis length shows a positive indication of twinning. The trigonal crystal of longer c axis, which appeared only after eight months of incubation at room temperature, is likely to be composed of proteolytically degraded molecules and unlike the other crystal forms contains two entire Bence-Jones dimers in the asymmetric unit. This latter crystal form may shed some light on the formation of fibrils common to certain storage diseases

Efficient Scalable Median Filtering Using Histogram-Based Operations.

Science.gov (United States)

Green, Oded

2018-05-01

Median filtering is a smoothing technique for noise removal in images. While there are various implementations of median filtering for a single-core CPU, there are few implementations for accelerators and multi-core systems. Many parallel implementations of median filtering use a sorting algorithm for rearranging the values within a filtering window and taking the median of the sorted value. While using sorting algorithms allows for simple parallel implementations, the cost of the sorting becomes prohibitive as the filtering windows grow. This makes such algorithms, sequential and parallel alike, inefficient. In this work, we introduce the first software parallel median filtering that is non-sorting-based. The new algorithm uses efficient histogram-based operations. These reduce the computational requirements of the new algorithm while also accessing the image fewer times. We show an implementation of our algorithm for both the CPU and NVIDIA's CUDA supported graphics processing unit (GPU). The new algorithm is compared with several other leading CPU and GPU implementations. The CPU implementation has near perfect linear scaling with a speedup on a quad-core system. The GPU implementation is several orders of magnitude faster than the other GPU implementations for mid-size median filters. For small kernels, and , comparison-based approaches are preferable as fewer operations are required. Lastly, the new algorithm is open-source and can be found in the OpenCV library.

Super-resolution with an optically-addressable liquid crystal spatial light modulator

International Nuclear Information System (INIS)

McOrist, J.; Sharma, M.D.; Sheppard, C.J.R.

2002-01-01

Full text: An optically-addressable liquid crystal spatial light modulator has been used to generate super-resolving masks. This approach avoids problems of low efficiency and coupling between amplitude and phase modulation, that occur when using conventional liquid crystal modulators. When addressed by a programmed light intensity distribution, it allows filters to be changed rapidly to modify the response of a system or permit the investigation of different filter designs. The device used is not pixellated, with a spatial resolution of 30 line pairs/mm over an area 18mm X 18mm, and can achieve continuously-variable phase modulation up to 1.5 wavelengths. The system consists of a write-beam that is collimated from a white-light source. An input mask was used in our experiments determines the modulation pattern of the read-beam. The read-beam from a HeNe laser reflects from the modulator and is focused by a microscope objective. The value of the phase change induced by the transparent regions of the mask can be altered continuously by adjusting the brightness of the write-beam. We have used this system to attain super-resolution by simple Toraldo filters, consisting of arrays of rings. Copyright (2002) Australian Society for Electron Microscopy Inc

Characteristics of poly- and mono-crystalline BeO and SiO{sub 2} as thermal and cold neutron filters

Energy Technology Data Exchange (ETDEWEB)

Adib, M.; Habib, N. [Reactor Physics Department, NRC, Atomic Energy Authority, Cairo (Egypt); Bashter, I.I. [Physics Department, Faculty of Science, Zagazig University (Egypt); Morcos, H.N.; El-Mesiry, M.S. [Reactor Physics Department, NRC, Atomic Energy Authority, Cairo (Egypt); Mansy, M.S., E-mail: drmohamedmansy88@hotmail.com [Reactor Physics Department, NRC, Atomic Energy Authority, Cairo (Egypt)

2015-09-01

Highlights: • Neutron filtering features of BeO and SiO{sub 2} poly- and mono-crystals. • Calculations of the cold and thermal neutron cross sections and transmission with the code “HEXA-FILTERS”. • Optimal mosaic spread, thicknesses and cutting planes for BeO and SiO{sub 2} mono-crystals. - Abstract: A simple model along with a computer code “HEXA-FILTERS” is used to carry out the calculation of the total cross-sections of BeO and SiO{sub 2} having poly or mono-crystalline form as a function of neutron wavelength at room (R.T.) and liquid nitrogen (L.N.) temperatures. An overall agreement is indicated between the calculated neutron cross-sections and experimental data. Calculation shows that 25 cm thick of polycrystalline BeO cooled at liquid nitrogen temperature was found to be a good filter for neutron wavelengths longer than 0.46 nm. While, 50 cm of SiO{sub 2}, with much less transmission, for neutrons with wavelengths longer than 0.85 nm. It was also found that 10 cm of BeO and 15 cm SiO{sub 2} thick mono-crystals cut along their (0 0 2) plane, with 0.5° FWHM on mosaic spread and cooled at L.N., are a good thermal neutron filter, with high effect-to-noise ratio.

Characterization of Crystal Chirality in Amino Acids Using Low-Frequency Raman Spectroscopy.

Science.gov (United States)

Aviv, Hagit; Nemtsov, Irena; Mastai, Yitzhak; Tischler, Yaakov R

2017-10-19

We present a new method for differentiating racemic crystals from enantiopure crystals. Recently, developments in optical filters have enabled the facile use of Raman spectroscopy to detect low-frequency vibrational (LFV) modes. Here, for the first time, we use Raman spectroscopy to characterize the LFV modes for crystalline organic materials composed of chiral molecules. The LF-Raman spectra of racemic and enantiopure crystals exhibit a significant variation, which we attribute to different hydrogen-bond networks in the chiral crystal structures. Across a representative set of amino acids, we observed that when comparing racemic versus enantiopure crystals, the available LFV modes and their relative scattering intensity are strong functions of side chain polarity. Thus, LF-Raman can be used as a method that is complementary to the currently used methods for characterizing crystal chirality due to simpler, faster, and more sensitive measurements, along with the small sample size required, which is limited by the laser-beam diameter in the focus.

The security management of spent filter cartridge in Qinshan phase 3 (heavy water reactor) nuclear power plant

International Nuclear Information System (INIS)

Xue Dahai

2005-01-01

Qinshan phase 3 nuclear power plant is the first CANDU plant that China fetched in from Canada, and both two units operate under well condition up to now. The radioactive wastes produced during the unit operation mainly include technical waste, spent resin, and spent filter cartridge. The spent filter cartridge is one important part both in the volume and radioactivity of the radioactive waste, and it is the important content of radioactive waste management. Different from PWR, part of high radioactive spent filter in CANDU unit comes from heavy water system such as moderator system. It has to be dried through blowing before replaced from the system. But this working procedure result the filtrate dreg become flexible, and it can bring on the risk of internal or external exposure. It is very important to pay high attention to control the contamination spread during spent filter inside transfer. (authors)

The ''Gent'' stacked filter unit (SFU) sampler for the collection of atmospheric aerosols in two size fractions: Description and instructions for installation and use

International Nuclear Information System (INIS)

Maenhaut, W.; Francois, F.; Cafmeyer, J.

1994-01-01

This report contains a description and general instructions for the installation and use of the ''Gent'' Stacked Filter Unit (SFU) PM10 sampler. The sampler operates at a flow rate of 16 litres per min. It collects particulates which have an equivalent aerodynamic diameter (EAD) of less than 10 μm in separate ''coarse'' (2-10 μm EAD) and ''fine'' ( 10 μm EAD particles is accomplished by a PM10 pre-impaction stage upstream of the stacked filter cassette. The air is drawn through the sampler by means of a diaphragm vacuum pump, which is enclosed in a special housing together with a needle valve, vacuum gauge, flow meter, volume meter, time switch (for interrupted sampling) and hour meter. A list of manufacturers of the various components of the sampler is also given. (author). 4 figs, 1 tab

Highly uniform residual layers for arrays of 3D nanoimprinted cavities in Fabry-Pérot-filter-array-based nanospectrometers

Science.gov (United States)

Memon, Imran; Shen, Yannan; Khan, Abdullah; Woidt, Carsten; Hillmer, Hartmut

2016-04-01

Miniaturized optical spectrometers can be implemented by an array of Fabry-Pérot (FP) filters. FP filters are composed of two highly reflecting parallel mirrors and a resonance cavity. Each filter transmits a small spectral band (filter line) depending on its individual cavity height. The optical nanospectrometer, a miniaturized FP-based spectrometer, implements 3D NanoImprint technology for the fabrication of multiple FP filter cavities in a single process step. However, it is challenging to avoid the dependency of residual layer (RL) thickness on the shape of the printed patterns in NanoImprint. Since in a nanospectrometer the filter cavities vary in height between neighboring FP filters and, thus, the volume of each cavity varies causing that the RL varies slightly or noticeably between different filters. This is one of the few disadvantages of NanoImprint using soft templates such as substrate conformal imprint lithography which is used in this paper. The advantages of large area soft templates can be revealed substantially if the problem of laterally inhomogeneous RLs can be avoided or reduced considerably. In the case of the nanospectrometer, non-uniform RLs lead to random variations in the designed cavity heights resulting in the shift of desired filter lines. To achieve highly uniform RLs, we report a volume-equalized template design with the lateral distribution of 64 different cavity heights into several units with each unit comprising four cavity heights. The average volume of each unit is kept constant to obtain uniform filling of imprint material per unit area. The imprint results, based on the volume-equalized template, demonstrate highly uniform RLs of 110 nm thickness.

Removal of phosphorus, fluoride and metals from a gypsum mining leachate using steel slag filters.

Science.gov (United States)

Claveau-Mallet, Dominique; Wallace, Scott; Comeau, Yves

2013-03-15

The objective of this work was to evaluate the capacity of steel slag filters to treat a gypsum mining leachate containing 11-107 mg P/L ortho-phosphates, 9-37 mg/L fluoride, 0.24-0.83 mg/L manganese, 0.20-3.3 zinc and 1.7-8.2 mg/L aluminum. Column tests fed with reconstituted leachates were conducted for 145-222 days and sampled twice a week. Two types of electric arc furnace (EAF) slags and three filter sequences were tested. The voids hydraulic retention time (HRT(v)) of columns ranged between 4.3 and 19.2 h. Precipitates of contaminants present in columns were sampled and analyzed with X-ray diffraction at the end of tests. The best removal efficiencies over a period of 179 days were obtained with sequential filters that were composed of Fort Smith EAF slag operated at a total HRT(v) of 34 h which removed 99.9% of phosphorus, 85.3% of fluoride, 98.0% of manganese and 99.3% of zinc. Mean concentration at this system's effluent was 0.04 mg P/L ortho-phosphates, 4 mg/L fluoride, 0.02 mg/L manganese, 0.02 zinc and 0.5 mg/L aluminum. Thus, slag filters are promising passive and economical systems for the remediation of mining effluents. Phosphorus was removed by the formation of apatite (hydroxyapatite, Ca(5)(PO(4))(3)OH or fluoroapatite, Ca(5)(PO(4))(3)F) as confirmed by visual and X-ray diffraction analyses. The growth rate of apatite was favored by a high phosphorus concentration. Calcite crystals were present in columns and appeared to be competing for calcium and volume needed for apatite formation. The calcite crystal growth rate was higher than that of apatite crystals. Fluoride was removed by precipitation of fluoroapatite and its removal was favored by a high ratio of phosphorus to fluoride in the wastewater. Copyright © 2012 Elsevier Ltd. All rights reserved.

A simple gold-coated microstructure fiber polarization filter in two communication windows

Science.gov (United States)

Feng, Xinxing; Li, Shuguang; Du, Huijing; Zhang, Yinan; Liu, Qiang

2018-03-01

A polarization filter is designed at two communication windows of 1310 and 1550 nm based on microstructured optical fiber. The model has four large diameter air holes and two gold-coated air holes. The influence of the geometrical parameters of the photonic crystal fiber on the performance of the polarization filter is analyzed by the finite element method. The numerical simulation shows that when the fiber length is 300 μm, the corresponding extinction ratio is 209.7 dB and 179.8 dB, the bandwidth of extinction ratio (ER) better than 20 dB is 150 nm and 350 nm at the communication wavelength of 1310 nm and 1550 nm.

Generalized Phase Contrast with matched filtering using LCoS pico-projectors

OpenAIRE

Bañas, Andrew Rafael; Palima, Darwin; Glückstad, Jesper

2012-01-01

We report a beam shaping system for generating high intensity programmable opticalspots using mGPC: matched filtering combined with Generalized Phase Contrastapplying two consumer handheld pico-projectors. Such a system presents a low costalternative for optical trapping and manipulation, optical lattices and other beamshaping applications usually implemented with high-end spatial light modulators.Portable pico-projectors based on liquid crystal on silicon (LCoS) devices were usedas binary ph...

Unit for air decontamination

International Nuclear Information System (INIS)

Mariano H, E.

1991-02-01

To fulfill the applicable requirements of safety to the ventilation systems in nuclear facilities, it is necessary to make a cleaning of the air that hurtles to the atmosphere. For that which was designed and it manufactured an unit for decontamination of the air for the Pilot plant of production of Nuclear Fuel that this built one with national parts, uses Hepa national filters and the design can adapt for different dimensions of filters, also can be added a lodging for a prefilter or to adopt two Hepa filters. (Author)

Filter assembly for metallic and intermetallic tube filters

Science.gov (United States)

Alvin, Mary Anne; Lippert, Thomas E.; Bruck, Gerald J.; Smeltzer, Eugene E.

2001-01-01

A filter assembly (60) for holding a filter element (28) within a hot gas cleanup system pressure vessel is provided, containing: a filter housing (62), said filter housing having a certain axial length and having a peripheral sidewall, said sidewall defining an interior chamber (66); a one piece, all metal, fail-safe/regenerator device (68) within the interior chamber (66) of the filter housing (62) and/or extending beyond the axial length of the filter housing, said device containing an outward extending radial flange (71) within the filter housing for seating an essential seal (70), the device also having heat transfer media (72) disposed inside and screens (80) for particulate removal; one compliant gasket (70) positioned next to and above the outward extending radial flange of the fail-safe/regenerator device; and a porous metallic corrosion resistant superalloy type filter element body welded at the bottom of the metal fail-safe/regenerator device.

Statistically-Efficient Filtering in Impulsive Environments: Weighted Myriad Filters

Directory of Open Access Journals (Sweden)

Juan G. Gonzalez

2002-01-01

Full Text Available Linear filtering theory has been largely motivated by the characteristics of Gaussian signals. In the same manner, the proposed Myriad Filtering methods are motivated by the need for a flexible filter class with high statistical efficiency in non-Gaussian impulsive environments that can appear in practice. Myriad filters have a solid theoretical basis, are inherently more powerful than median filters, and are very general, subsuming traditional linear FIR filters. The foundation of the proposed filtering algorithms lies in the definition of the myriad as a tunable estimator of location derived from the theory of robust statistics. We prove several fundamental properties of this estimator and show its optimality in practical impulsive models such as the α-stable and generalized-t. We then extend the myriad estimation framework to allow the use of weights. In the same way as linear FIR filters become a powerful generalization of the mean filter, filters based on running myriads reach all of their potential when a weighting scheme is utilized. We derive the “normal” equations for the optimal myriad filter, and introduce a suboptimal methodology for filter tuning and design. The strong potential of myriad filtering and estimation in impulsive environments is illustrated with several examples.

Filter material charging apparatus for filter assembly for radioactive contaminants

International Nuclear Information System (INIS)

Goldsmith, J.M.; O'Nan, A. Jr.

1977-01-01

A filter charging apparatus for a filter assembly is described. The filter assembly includes a housing with at least one filter bed therein and the filter charging apparatus for adding filter material to the filter assembly includes a tank with an opening therein, the tank opening being disposed in flow communication with opposed first and second conduit means, the first conduit means being in flow communication with the filter assembly housing and the second conduit means being in flow communication with a blower means. Upon activation of the blower means, the blower means pneumatically conveys the filter material from the tank to the filter housing

Fabrication of Refractive Index Tunable Polydimethylsiloxane Photonic Crystal for Biosensor Application

Science.gov (United States)

Raman, Karthik; Murthy, T. R. Srinivasa; Hegde, G. M.

Photonic crystal based nanostructures are expected to play a significant role in next generation nanophotonic devices. Recent developments in two-dimensional (2D) photonic crystal based devices have created widespread interest as such planar photonic structures are compatible with conventional microelectronic and photonic devices. Various optical components such as waveguides, resonators, modulators and demultiplexers have been designed and fabricated based on 2D photonic crystal geometry. This paper presents the fabrication of refractive index tunable Polydimethylsiloxane (PDMS) polymer based photonic crystals. The advantages of using PDMS are mainly its chemical stability, bio-compatibility and the stack reduces sidewall roughness scattering. The PDMS structure with square lattice was fabricated by using silicon substrate patterned with SU8-2002 resist. The 600 nm period grating of PDMS is then fabricated using Nano-imprinting. In addition, the refractive index of PDMS is modified using certain additive materials. The resulting photonic crystals are suitable for application in photonic integrated circuits and biological applications such as filters, cavities or microlaser waveguides.

Application of difference filter to Feynman-α analysis

International Nuclear Information System (INIS)

Mouri, Tomoaki; Ohtani, Nobuo

1997-11-01

The Feynman-α method has been developed for monitoring sub-criticality in nuclear fuel facilities. It is difficult to apply the Feynman-α method which estimates statistical variation of the number of neutron counts per unit time, to the system in transient condition such that the averaged neutron flux varies with time. In the application of Feynman-α method to such system, it is suggested to remove the averaged variation of neutron flux from neutron count data by the use of the difference filter. In this study, we applied the difference filter to reactor noise data at sub-criticality near to criticality, where the prompt decay constant was difficult to estimate due to the large effect of delayed neutron. With the difference filter, accurate prompt decay constants for effective multiplication factors from 0.999 to 0.994 were obtained by Feynman-α method. It was cleared that the difference filter is effective to estimate accurate prompt decay constant, so that there is the prospect to be able to apply Feynman-α method having the difference filter to the system in the transient condition. (author)

Development of a ten inch manipulators-based, flexible, broadband two-crystal spectrometer

International Nuclear Information System (INIS)

Steel, A. B.; Dunn, J.; Emig, J.; Beiersdorfer, P.; Brown, G. V.; Shepherd, R.; Marley, E. V.; Hoarty, D. J.

2014-01-01

We have developed and implemented a broadband X-ray spectrometer with a variable energy range for use at the Atomic Weapons Establishment's Orion Laser. The spectrometer covers an energy bandwidth of ∼1–2 keV using two independently mounted, movable Bragg diffraction crystals. Using combinations of cesium hydrogen pthlate, ammonium dihydrogen phosphate, and pentaerythritol crystals, spectra covering the 1.4–2.5, 1.85–3.15, or 3.55–5.1 keV energy bands have been measured. Image plate is used for detection owing to its high dynamic range. Background signals caused by high energy X-rays and particles commonly produced in high energy laser experiments are reduced by a series of tantalum baffles and filters installed between the source and crystal and also between the crystals and detector

Butterfly wing color: A photonic crystal demonstration

Science.gov (United States)

Proietti Zaccaria, Remo

2016-01-01

We have theoretically modeled the optical behavior of a natural occurring photonic crystal, as defined by the geometrical characteristics of the Teinopalpus Imperialis butterfly. In particular, following a genetic algorithm approach, we demonstrate how its wings follow a triclinic crystal geometry with a tetrahedron unit base. By performing both photonic band analysis and transmission/reflection simulations, we are able to explain the characteristic colors emerging by the butterfly wings, thus confirming their crystal form.

Development, characterization, and modeling of a tunable filter camera

Science.gov (United States)

Sartor, Mark Alan

1999-10-01

This paper describes the development, characterization, and modeling of a Tunable Filter Camera (TFC). The TFC is a new multispectral instrument with electronically tuned spectral filtering and low-light-level sensitivity. It represents a hybrid between hyperspectral and multispectral imaging spectrometers that incorporates advantages from each, addressing issues such as complexity, cost, lack of sensitivity, and adaptability. These capabilities allow the TFC to be applied to low- altitude video surveillance for real-time spectral and spatial target detection and image exploitation. Described herein are the theory and principles of operation for the TFC, which includes a liquid crystal tunable filter, an intensified CCD, and a custom apochromatic lens. The results of proof-of-concept testing, and characterization of two prototype cameras are included, along with a summary of the design analyses for the development of a multiple-channel system. A significant result of this effort was the creation of a system-level model, which was used to facilitate development and predict performance. It includes models for the liquid crystal tunable filter and intensified CCD. Such modeling was necessary in the design of the system and is useful for evaluation of the system in remote-sensing applications. Also presented are characterization data from component testing, which included quantitative results for linearity, signal to noise ratio (SNR), linearity, and radiometric response. These data were used to help refine and validate the model. For a pre-defined source, the spatial and spectral response, and the noise of the camera, system can now be predicted. The innovation that sets this development apart is the fact that this instrument has been designed for integrated, multi-channel operation for the express purpose of real-time detection/identification in low- light-level conditions. Many of the requirements for the TFC were derived from this mission. In order to provide

Development and evaluation of a cleanable high efficiency steel filter

International Nuclear Information System (INIS)

Bergman, W.; Larsen, G.; Weber, F.; Wilson, P.; Lopez, R.; Valha, G.; Conner, J.; Garr, J.; Williams, K.; Biermann, A.; Wilson, K.; Moore, P.; Gellner, C.; Rapchun, D.; Simon, K.; Turley, J.; Frye, L.; Monroe, D.

1993-01-01

We have developed a high efficiency steel filter that can be cleaned in-situ by reverse air pulses. The filter consists of 64 pleated cylindrical filter elements packaged into a 6l0 x 6l0 x 292 mm aluminum frame and has 13.5 m 2 of filter area. The filter media consists of a sintered steel fiber mat using 2 μm diameter fibers. We conducted an optimization study for filter efficiency and pressure drop to determine the filter design parameters of pleat width, pleat depth, outside diameter of the cylinder, and the total number of cylinders. Several prototype cylinders were then built and evaluated in terms of filter cleaning by reverse air pulses. The results of these studies were used to build the high efficiency steel filter. We evaluated the prototype filter for efficiency and cleanability. The DOP filter certification test showed the filter has a passing efficiency of 99.99% but a failing pressure drop of 0.80 kPa at 1,700 m 3 /hr. Since we were not able to achieve a pressure drop less than 0.25 kPa, the steel filter does not meet all the criteria for a HEPA filter. Filter loading and cleaning tests using AC Fine dust showed the filter could be repeatedly cleaned by reverse air pulses. The next phase of the prototype evaluation consisted of installing the unit and support housing in the exhaust duct work of a uranium grit blaster for a field evaluation at the Y-12 Plant in Oak Ridge, TN. The grit blaster is used to clean the surface of uranium parts and generates a cloud of UO 2 aerosols. We used a 1,700 m 3 /hr slip stream from the 10,200 m 3 /hr exhaust system

Planar Superconducting Millimeter-Wave/Terahertz Channelizing Filter

Science.gov (United States)

Ehsan, Negar; U-yen, Kongpop; Brown, Ari; Hsieh, Wen-Ting; Wollack, Edward; Moseley, Samuel

2013-01-01

This innovation is a compact, superconducting, channelizing bandpass filter on a single-crystal (0.45 m thick) silicon substrate, which operates from 300 to 600 GHz. This device consists of four channels with center frequencies of 310, 380, 460, and 550 GHz, with approximately 50-GHz bandwidth per channel. The filter concept is inspired by the mammalian cochlea, which is a channelizing filter that covers three decades of bandwidth and 3,000 channels in a very small physical space. By using a simplified physical cochlear model, and its electrical analog of a channelizing filter covering multiple octaves bandwidth, a large number of output channels with high inter-channel isolation and high-order upper stopband response can be designed. A channelizing filter is a critical component used in spectrometer instruments that measure the intensity of light at various frequencies. This embodiment was designed for MicroSpec in order to increase the resolution of the instrument (with four channels, the resolution will be increased by a factor of four). MicroSpec is a revolutionary wafer-scale spectrometer that is intended for the SPICA (Space Infrared Telescope for Cosmology and Astrophysics) Mission. In addition to being a vital component of MicroSpec, the channelizing filter itself is a low-resolution spectrometer when integrated with only an antenna at its input, and a detector at each channel s output. During the design process for this filter, the available characteristic impedances, possible lumped element ranges, and fabrication tolerances were identified for design on a very thin silicon substrate. Iterations between full-wave and lumped-element circuit simulations were performed. Each channel s circuit was designed based on the availability of characteristic impedances and lumped element ranges. This design was based on a tabular type bandpass filter with no spurious harmonic response. Extensive electromagnetic modeling for each channel was performed. Four channels

The Military Efficacy of Individual Water Purification Filters.

Science.gov (United States)

1990-12-01

criteria. ’t *.;as a.Lso serv ea that the KPF units grew opportunistic Pseudomonas sp . on the oroduct water side of the filters, which could have a...small pathogenic protozoan cysts such as Cryptospor-dium parvum, Giardia lamblia, and Entamoeba coli, from water over the effective use life of the...of heterotrophic bacteria such as Pseudoronas sP , Flavobacterium Sp , and other potentially harmfui organisms inside of the units. Enteric viruses are

New piezoelectric materials for SAW filters

Science.gov (United States)

Anghelescu, Adrian; Nedelcu, Monica

2010-11-01

Scientific research of surface acoustic wave (SAW) devices had an early start by the end of 1960s and led to the development of high frequency and small size piezo devices. A sustained effort was dedicated for these components to be transformed into many more interesting applications for telecom market. Recently the employment of new piezo materials and crystallographic orientations open new opportunities for SAW filters. New piezoelectric crystals of gallium orthophosphate (GaPO4) provide higher electromechanical coupling than quartz, while maintaining temperature compensated characteristics similar to quartz. Based on this material phase transition of 970°C, development of new piezo devices to operate at higher temperatures up to 800°C can be done. SAW velocities about 30% lower than ST-X quartz, favors smaller and more compact devices. Other advantages of GaPO4 are: stability with high resistance to stress induced twinning, 3~4 times higher electromechanical coupling than quartz and existence of SAW temperature compensated orientations. Another family of new materials of the trigonal 32 class has received much attention recently because of their temperature behavior similar to quartz and the promise of higher electromechanical coupling coefficients. It is the family of langasite (LGS, La3Ga5SiO14), langatate (LGT, La3Ga5.5Ta0.5O14) and langanite (La3Ga5.5Nb0.5O14). Langasite crystals, easier to obtain and with the value of electromechanical coupling coefficient intermediate between quartz and lithium tantalate (k2=0.32% for 0°, 140°, 22.5° orientation and k2=0.38% for 0°, 140°, 25° orientation), enable us to design SAW filters with a relative pass band of 0.3% to 0.85%. Other piezoelectric materials are reviewed for comparison.

Four crystal forms of a Bence-Jones protein

Energy Technology Data Exchange (ETDEWEB)

Makino, Debora L.; Henschen-Edman, Agnes H.; McPherson, Alexander, E-mail: amcphers@uci.edu [Molecular Biology and Biochemistry, University of California, Irvine, 560 Steinhaus Hall, Irvine, CA 92697-3900 (United States)

2005-01-01

Four crystal forms have been grown and characterized by X-ray diffraction of a Bence-Jones protein collected from the urine of a multiple myeloma patient more than 40 y ago. The trigonal crystal form may shed some light on the formation of fibrils common to certain storage diseases. Four crystal forms have been grown and characterized by X-ray diffraction of a Bence-Jones protein collected from the urine of a multiple myeloma patient more than 40 years ago. Closely related tetragonal and orthorhombic forms belonging to space groups P4{sub 3}2{sub 1}2 and P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = b = 68.7, c = 182.1 and a = 67.7, b = 69.4, c = 87.3 Å, diffract to 1.5 and 1.9 Å, respectively. Two closely related trigonal forms, both belonging to space group P3{sub 1}21 with unit-cell parameters a = b = 154.3 Å but differing by a doubling of the c axis, one 46.9 Å and the other 94.0 Å, diffract to 2.9 and 2.6 Å resolution, respectively. The trigonal crystal of short c-axis length shows a positive indication of twinning. The trigonal crystal of longer c axis, which appeared only after eight months of incubation at room temperature, is likely to be composed of proteolytically degraded molecules and unlike the other crystal forms contains two entire Bence-Jones dimers in the asymmetric unit. This latter crystal form may shed some light on the formation of fibrils common to certain storage diseases.

DEVELOPMENT OF AG-1 SECTION FI ON METAL MEDIA FILTERS - 9061

International Nuclear Information System (INIS)

Adamson, D.; Waggoner, C.A.

2008-01-01

Development of a metal media standard (FI) for ASME AG-1 (Code on Nuclear Air and Gas Treatment) has been under way for almost ten years. This paper will provide a brief history of the development process of this section and a detailed overview of its current content/status. There have been at least two points when dramatic changes have been made in the scope of the document due to feedback from the full Committee on Nuclear Air and Gas Treatment (CONAGT). Development of the proposed section has required resolving several difficult issues associated with scope; namely, filtering efficiency, operating conditions (media velocity, pressure drop, etc.), qualification testing, and quality control/acceptance testing. A proposed version of Section FI is currently undergoing final revisions prior to being submitted for balloting. The section covers metal media filters of filtering efficiencies ranging from medium (less than 99.97%) to high (99.97% and greater). Two different types of high efficiency filters are addressed; those units intended to be a direct replacement of Section FC fibrous glass HEPA filters and those that will be placed into newly designed systems capable of supporting greater static pressures and differential pressures across the filter elements. Direct replacements of FC HEPA filters in existing systems will be required to meet equivalent qualification and testing requirements to those contained in Section FC. A series of qualification and quality assurance test methods have been identified for the range of filtering efficiencies covered by this proposed standard. Performance characteristics of sintered metal powder vs. sintered metal fiber media are dramatically different with respect to parameters like differential pressures and rigidity of the media. Wide latitude will be allowed for owner specification of performance criteria for filtration units that will be placed into newly designed systems. Such allowances will permit use of the most

Experimental relationship between the specific resistance of a HEPA [High Efficiency Particulate Air] filter and particle diameters of different aerosol materials

International Nuclear Information System (INIS)

Novick, V.J.; Monson, P.R.; Ellison, P.E.

1990-01-01

The increase in pressure drop across a HEPA filter has been measured as a function of the particle mass loading using two materials with different particle morphologies. The HEPA filter media chosen, is identical to the filter media used in the Airborne Activity Confinement System (AACS) on the Savannah River Reactors. The velocity through the test filter media was the same as the velocity through the AACS media, under normal operating flow conditions. Sodium Chloride challenge particles were generated using an atomizer, resulting in regularly shaped crystalline forms. Ammonium chloride aerosols were formed from the gas phase reaction of HCl and NH 4 OH vapors resulting in irregular agglomerates. In both cases, the generation conditions were adjusted to provide several different particle size distributions. For each particle size distribution, the mass of material loaded per unit area of filter per unit pressure drop for a given filtration velocity (1/Specific resistance) was measured. Theoretical considerations in the most widely accepted filter cake model predict that the mass per unit area and per unit pressure drop should increase with the particle density times the particle diameter squared. However, these test results indicate that the increase in the mass loaded per unit area per unit pressure drop, for both materials, can be better described by plotting the specific resistance divided by the particle density as an inverse function of the particle density times the particle diameter squared. 9 refs., 7 figs

Automation of the electromagnetic filter applied for condensation water treatment in the secondary cooling system of the Paks Nuclear Power Plant

International Nuclear Information System (INIS)

Szilagyi, Gyoergy

1989-01-01

A full-flow condensation water purification system is applied in the secondary cooling circuit of the Paks NPP. The electromagnetic filter of the filtering system eliminates ferromagnetic impurities. The filter consists of a high current coil and an automatic control unit. During the improvement of this unit, a FESTO FPC-404 type controller based on an extended capability PLC was installed. (R.P.) 5 figs

42 CFR 84.1151 - DOP filter test; respirators designed as respiratory protection against dusts, fumes, and mists...

Science.gov (United States)

2010-10-01

... 42 Public Health 1 2010-10-01 2010-10-01 false DOP filter test; respirators designed as... filter test; respirators designed as respiratory protection against dusts, fumes, and mists having an air...) All single air-purifying respirator filter units will be tested in an atmosphere concentration of 100...

Quartz crystal fabrication facility

Science.gov (United States)

Ney, R. J.

1980-05-01

The report describes the design and operation of a five chamber, interconnected vacuum system, which is capable of cleaning, plating, and sealing precision quartz crystal units in ceramic flatpack enclosures continuously in a high vacuum environment. The production rate design goal was 200 units per eight hour day. A unique nozzle beam gold deposition source was developed to operate for extended periods of time without reloading. The source puts out a narrow beam of gold typically in the order of 2 1/2 deg included cone angle. Maximum deposition rates are in the order of 400 a/min at 5.5 in. 'throw' distance used. Entrance and exit air lock chambers expedite the material throughput, so that the processing chambers are at high vacuum for extended periods of time. A stainless steel conveyor belt, in conjunction with three vacuum manipulators, transport the resonator components to the various work stations. Individual chambers are normally separated from each other by gate valves. The crystal resonators, mounted in flatpack frames but unplated, are loaded into transport trays in a lid-frame-lid sequency for insertion into the system and exit as completed crystal units. The system utilizes molybdenum coated ball bearings at essentially all friction surfaces. The gold sources and plating mask heads are equipped with elevators and gate valves, so that they can be removed from the system for maintenance without exposing the chambers to atmosphere.

Crystallization and preliminary crystallographic analysis of human glycosylated haemoglobin

International Nuclear Information System (INIS)

Syakhovich, Vitaly E.; Saraswathi, N. T.; Ruff, Marc; Bokut, Sergey B.; Moras, Dino

2006-01-01

Non enzymatic modification of haemoglobin by glucose plays an important role in diabetes pathogenesis. Here the purification, characterization and crystallization of human glycosylated haemoglobin are reported. Human glycosylated haemoglobin A 1C is a stable minor variant formed in vivo by post-translational modification of the main form of haemoglobin by glucose. Crystals of oxyHbA 1C were obtained using the hanging-drop vapour-diffusion method and PEG as precipitant. The diffraction pattern of the crystal extends to a resolution of 2.3 Å at 120 K. The crystals belong to space group C2, with unit-cell parameters a = 237.98, b = 59.27, c = 137.02 Å, α = 90.00, β = 125.40, γ = 90.00°. The presence of two and a half molecules per asymmetric unit gives a crystal volume per protein weight (V M ) of 9.70 Å 3 Da −1 and a solvent content of 49%

Crystallization and preliminary crystallographic analysis of human glycosylated haemoglobin

Energy Technology Data Exchange (ETDEWEB)

Syakhovich, Vitaly E. [Department of Biochemistry and Biophysics, International Sakharov Environmental University, Dolgobrodskaya St 23, 220009 Minsk (Belarus); Saraswathi, N. T.; Ruff, Marc, E-mail: ruff@igbmc.u-strasbg.fr [Département de Biologie et Génomique Structurales, Institut de Génétique et de Biologie Moléculaire et Cellulaire, 1 Rue Laurent Fries, BP 10142, 67404 Illkirch (France); Bokut, Sergey B. [Department of Biochemistry and Biophysics, International Sakharov Environmental University, Dolgobrodskaya St 23, 220009 Minsk (Belarus); Moras, Dino [Département de Biologie et Génomique Structurales, Institut de Génétique et de Biologie Moléculaire et Cellulaire, 1 Rue Laurent Fries, BP 10142, 67404 Illkirch (France); Department of Biochemistry and Biophysics, International Sakharov Environmental University, Dolgobrodskaya St 23, 220009 Minsk (Belarus)

2006-02-01

Non enzymatic modification of haemoglobin by glucose plays an important role in diabetes pathogenesis. Here the purification, characterization and crystallization of human glycosylated haemoglobin are reported. Human glycosylated haemoglobin A{sub 1C} is a stable minor variant formed in vivo by post-translational modification of the main form of haemoglobin by glucose. Crystals of oxyHbA{sub 1C} were obtained using the hanging-drop vapour-diffusion method and PEG as precipitant. The diffraction pattern of the crystal extends to a resolution of 2.3 Å at 120 K. The crystals belong to space group C2, with unit-cell parameters a = 237.98, b = 59.27, c = 137.02 Å, α = 90.00, β = 125.40, γ = 90.00°. The presence of two and a half molecules per asymmetric unit gives a crystal volume per protein weight (V{sub M}) of 9.70 Å{sup 3} Da{sup −1} and a solvent content of 49%.

Parasitic neutron bragg reflections from large imperfect single crystals

Energy Technology Data Exchange (ETDEWEB)

Naguib, K.; Adib, M

1998-12-01

A formula is given which allows to calculate the contribution of the total Bragg scattering from different (hkl) planes to the neutron transmission through a large imperfect single crystals. The formula takes into account the crystal structure type, its mosaic spread value, the plane along which the crystal surface is cut along and its orientation with respect to the neutron beam direction. A computer program ISCANF-1 was developed to calculate the total parasitic scattering cross-section from different (hkl) planes as well as the nuclear and diffuse scattering cross-sections. The ISCANF-1 program was applied to calculate the neutron attenuation through Cu and Zn single crystals, each of them cut along (002) planes. The calculated values of the neutron transmission through Cu and Zn crystals were compared with the measured ones in the wavelength range 0.21-0.47 nm and 0.04-0.52 nm respectively. The measured and calculated values were found to be in reasonable agreement within the statistical accuracy. The computer program ISCANF-1 was also applied to investigate the effect of parasitic Bragg scattering on the neutron filtering characteristics of both Zn and Cu single crystals as a function of their physical parameters.

Parasitic neutron bragg reflections from large imperfect single crystals

International Nuclear Information System (INIS)

Naguib, K.; Adib, M.

1998-01-01

A formula is given which allows to calculate the contribution of the total Bragg scattering from different (hkl) planes to the neutron transmission through a large imperfect single crystals. The formula takes into account the crystal structure type, its mosaic spread value, the plane along which the crystal surface is cut along and its orientation with respect to the neutron beam direction. A computer program ISCANF-1 was developed to calculate the total parasitic scattering cross-section from different (hkl) planes as well as the nuclear and diffuse scattering cross-sections. The ISCANF-1 program was applied to calculate the neutron attenuation through Cu and Zn single crystals, each of them cut along (002) planes. The calculated values of the neutron transmission through Cu and Zn crystals were compared with the measured ones in the wavelength range 0.21-0.47 nm and 0.04-0.52 nm respectively. The measured and calculated values were found to be in reasonable agreement within the statistical accuracy. The computer program ISCANF-1 was also applied to investigate the effect of parasitic Bragg scattering on the neutron filtering characteristics of both Zn and Cu single crystals as a function of their physical parameters

Spectral characterization in deep UV of an improved imaging KDP acousto-optic tunable filter

International Nuclear Information System (INIS)

Gupta, Neelam; Voloshinov, Vitaly

2014-01-01

Recently, we developed a number of high quality noncollinear acousto-optic tunable filter (AOTF) cells in different birefringent materials with UV imaging capability. Cells based on a single crystal of KDP (potassium dihydrophosphate) had the best transmission efficiency and the optical throughput needed to acquire high quality spectral images at wavelengths above 220 nm. One of the main limitations of these imaging filters was their small angular aperture in air, limited to about 1.0°. In this paper, we describe an improved imaging KDP AOTF operating from the deep UV to the visible region of the spectrum. The linear and angular apertures of the new filter are 10 × 10 mm 2 and 1.8°, respectively. The spectral tuning range is 205–430 nm with a 60 cm −1 spectral resolution. We describe the filter and present experimental results on imaging using both a broadband source and a number of light emitting diodes (LEDs) in the UV, and include the measured spectra of these LEDs obtained with a collinear SiO 2 filter-based spectrometer operating above 255 nm. (paper)

Crystallization of Doc and the Phd–Doc toxin–antitoxin complex

International Nuclear Information System (INIS)

Garcia-Pino, Abel; Dao-Thi, Minh-Hoa; Gazit, Ehud; Magnuson, Roy David; Wyns, Lode; Loris, Remy

2008-01-01

Crystals of bacteriophage P1 Doc were grown in the free state, in complex with a 22-amino-acid C-terminal peptide of Phd and in complex with full-length Phd. The phd/doc addiction system is responsible for the stable inheritance of lysogenic bacteriophage P1 in its plasmidic form in Escherichia coli and is the archetype of a family of bacterial toxin–antitoxin modules. The His66Tyr mutant of Doc (Doc H66Y ) was crystallized in space group P2 1 , with unit-cell parameters a = 53.1, b = 198.0, c = 54.1 Å, β = 93.0°. These crystals diffracted to 2.5 Å resolution and probably contained four dimers of Doc in the asymmetric unit. Doc H66Y in complex with a 22-amino-acid C-terminal peptide of Phd (Phd 52-73Se ) was crystallized in space group C2, with unit-cell parameters a = 111.1, b = 38.6, c = 63.3 Å, β = 99.3°, and diffracted to 1.9 Å resolution. Crystals of the complete wild-type Phd–Doc complex belonged to space group P3 1 21 or P3 2 21, had an elongated unit cell with dimensions a = b = 48.9, c = 354.9 Å and diffracted to 2.4 Å resolution using synchrotron radiation

Voice preprocessing system incorporating a real-time spectrum analyzer with programmable switched-capacitor filters

Science.gov (United States)

Knapp, G.

1984-01-01

As part of a speaker verification program for BISS (Base Installation Security System), a test system is being designed with a flexible preprocessing system for the evaluation of voice spectrum/verification algorithm related problems. The main part of this report covers the design, construction, and testing of a voice analyzer with 16 integrating real-time frequency channels ranging from 300 Hz to 3 KHz. The bandpass filter response of each channel is programmable by NMOS switched capacitor quad filter arrays. Presently, the accuracy of these units is limited to a moderate precision by the finite steps of programming. However, repeatability of characteristics between filter units and sections seems to be excellent for the implemented fourth-order Butterworth bandpass responses. We obtained a 0.1 dB linearity error of signal detection and measured a signal-to-noise ratio of approximately 70 dB. The proprocessing system discussed includes preemphasis filter design, gain normalizer design, and data acquisition system design as well as test results.

Crystallization of Doc and the Phd-Doc toxin-antitoxin complex.

Science.gov (United States)

Garcia-Pino, Abel; Dao-Thi, Minh-Hoa; Gazit, Ehud; Magnuson, Roy David; Wyns, Lode; Loris, Remy

2008-11-01

The phd/doc addiction system is responsible for the stable inheritance of lysogenic bacteriophage P1 in its plasmidic form in Escherichia coli and is the archetype of a family of bacterial toxin-antitoxin modules. The His66Tyr mutant of Doc (Doc(H66Y)) was crystallized in space group P2(1), with unit-cell parameters a = 53.1, b = 198.0, c = 54.1 A, beta = 93.0 degrees . These crystals diffracted to 2.5 A resolution and probably contained four dimers of Doc in the asymmetric unit. Doc(H66Y) in complex with a 22-amino-acid C-terminal peptide of Phd (Phd(52-73Se)) was crystallized in space group C2, with unit-cell parameters a = 111.1, b = 38.6, c = 63.3 A, beta = 99.3 degrees , and diffracted to 1.9 A resolution. Crystals of the complete wild-type Phd-Doc complex belonged to space group P3(1)21 or P3(2)21, had an elongated unit cell with dimensions a = b = 48.9, c = 354.9 A and diffracted to 2.4 A resolution using synchrotron radiation.

Cake filtration modeling: Analytical cake filtration model and filter medium characterization

Energy Technology Data Exchange (ETDEWEB)

Koch, Michael

2008-05-15

Cake filtration is a unit operation to separate solids from fluids in industrial processes. The build up of a filter cake is usually accompanied with a decrease in overall permeability over the filter leading to an increased pressure drop over the filter. For an incompressible filter cake that builds up on a homogeneous filter cloth, a linear pressure drop profile over time is expected for a constant fluid volume flow. However, experiments show curved pressure drop profiles, which are also attributed to inhomogeneities of the filter (filter medium and/or residual filter cake). In this work, a mathematical filter model is developed to describe the relationship between time and overall permeability. The model considers a filter with an inhomogeneous permeability and accounts for fluid mechanics by a one-dimensional formulation of Darcy's law and for the cake build up by solid continuity. The model can be solved analytically in the time domain. The analytic solution allows for the unambiguous inversion of the model to determine the inhomogeneous permeability from the time resolved overall permeability, e.g. pressure drop measurements. An error estimation of the method is provided by rewriting the model as convolution transformation. This method is applied to simulated and experimental pressure drop data of gas filters with textile filter cloths and various situations with non-uniform flow situations in practical problems are explored. A routine is developed to generate characteristic filter cycles from semi-continuous filter plant operation. The model is modified to investigate the impact of non-uniform dust concentrations. (author). 34 refs., 40 figs., 1 tab

Growth of CuSO4 · 5H2O single crystals and study of some of their properties

Science.gov (United States)

Manomenova, V. L.; Stepnova, M. N.; Grebenev, V. V.; Rudneva, E. B.; Voloshin, A. E.

2013-05-01

Large single crystals of copper sulfate pentahydrate CuSO4 · 5H2O of optical quality have been grown; they can be applied as broadband UV optical filters. Their transmission spectra are measured. The crystal thermal stability is investigated and the onset temperature of dehydration is determined to be 46°C.

Crystal structure determination of Efavirenz

International Nuclear Information System (INIS)

Popeneciu, Horea; Dumitru, Ristoiu; Tripon, Carmen; Borodi, Gheorghe; Pop, Mihaela Maria

2015-01-01

Needle-shaped single crystals of the title compound, C 14 H 9 ClF 3 NO 2 , were obtained from a co-crystallization experiment of Efavirenz with maleic acid in a (1:1) ratio, using methanol as solvent. Crystal structure determination at room temperature revealed a significant anisotropy of the lattice expansion compared to the previously reported low-temperature structure. In both low- and room temperature structures the cyclopropylethynyl fragment in one of the asymmetric unit molecules is disordered. While at low-temperature only one C atom exhibits positional disorder, at room temperature the disorder is present for two C atoms of the cyclopropane ring

Multilayer Photonic Crystal for Spectral Narrowing of Emission

Directory of Open Access Journals (Sweden)

Zhanfang LIU

2017-08-01

Full Text Available Multilayer colloidal crystal has been prepared by the layer-by-layer deposition of silica microspheres on a glass slide. Each layer is a slab consisting of a fcc close-packed colloidal arrays. By properly choosing the sizes of spheres, the whole spectral feature of multilayer colloidal crystal can be tuned. Here, we engineered a multilayer superlattice structure with an effective passband between two stop bands. This gives a strong narrowing effect on emission spectrum. With the stop bands at the shortwave and longwave edges of emission spectrum, the passband in the central wavelength region can be regarded as a strong decrease of suppression effect and enhancement of a narrow wavelength region of emission. The spectral narrowing modification effect of suitably engineered colloidal crystals shows up their importance in potential application as optical filters and lasing devices.DOI: http://dx.doi.org/10.5755/j01.ms.23.3.16320

Experimental study of filter cake formation on different filter media

International Nuclear Information System (INIS)

Saleem, M.

2009-01-01

Removal of particulate matter from gases generated in the process industry is important for product recovery as well as emission control. Dynamics of filtration plant depend on operating conditions. The models, that predict filter plant behaviour, involve empirical resistance parameters which are usually derived from limited experimental data and are characteristics of the filter media and filter cake (dust deposited on filter medium). Filter cake characteristics are affected by the nature of filter media, process parameters and mode of filter regeneration. Removal of dust particles from air is studied in a pilot scale jet pulsed bag filter facility resembling closely to the industrial filters. Limestone dust and ambient air are used in this study with two widely different filter media. All important parameters like pressure drop, gas flow rate, dust settling, are recorded continuously at 1s interval. The data is processed for estimation of the resistance parameters. The pressure drop rise on test filter media is compared. Results reveal that the surface of filter media has an influence on pressure drop rise (concave pressure drop rise). Similar effect is produced by partially jet pulsed filter surface. Filter behaviour is also simulated using estimated parameters and a simplified model and compared with the experimental results. Distribution of cake area load is therefore an important aspect of jet pulse cleaned bag filter modeling. Mean specific cake resistance remains nearly constant on thoroughly jet pulse cleaned membrane coated filter bags. However, the trend can not be confirmed without independent cake height and density measurements. Thus the results reveal the importance of independent measurements of cake resistance. (author)

Hyper-spectral modulation fluorescent imaging using double acousto-optical tunable filter based on TeO2-crystals

International Nuclear Information System (INIS)

Zaytsev, Kirill I; Perchik, Alexey V; Chernomyrdin, Nikita V; Yurchenko, Stanislav O; Kudrin, Konstantin G; Reshetov, Igor V

2015-01-01

We have proposed a method for hyper-spectral fluorescent imaging based on acousto-optical filtering. The object of interest was pumped using ultraviolet radiation of mercury lamp equipped with monochromatic excitation filter with the window of transparency centered at 365 nm. Double TeO 2 -based acousto-optical filter, tunable in range from 430 to 780 nm and having 2 nm bandwidth of spectral transparency, was used in order to detect quasimonochromatic images of object fluorescence. Modulating of ultraviolet pump intensity was used in order to reduce an impact of non-fluorescent background on the sample fluorescent imaging. The technique for signal-to-noise ratio improvement, based on fluorescence intensity estimation via digital processing of modulated video sequence of fluorescent object, was introduced. We have implemented the proposed technique for the test sample studying and we have discussed its possible applications

On the use of silicon as thermal neutron filter

International Nuclear Information System (INIS)

Adib, M.; Habib, N.; Ashry, A.; Fathalla, M.

2003-01-01

A simple formula is given which allows to calculate the contribution of the total neutron cross-section including the Bragg scattering from different (hkl) planes to the neutron transmission through a solid crystalline silicon. The formula takes into account the silicon form of poly or mono crystals and its parameters. A computer program DSIC was developed to provide the required calculations. The calculated values of the total neutron cross-section of perfect silicon crystal at room and liquid nitrogen temperatures were compared with the experimental ones. The obtained agreement shows that the simple formula fits the experimental data with sufficient accuracy. A good agreement was also obtained between the calculated and measured values of polycrystalline silicon in the energy range from 5 eV to 500 μeV. The feasibility study on using a poly-crystalline silicon as a cold neutron filter and mono-crystalline as a thermal neutron one is given. The optimum crystal thickness, mosaic spread, temperature and cutting plane for efficiently transmitting the thermal reactor neutrons, while rejecting both fast neutrons and gamma rays accompanying the thermal ones for the mono crystalline silicon are also given

On the use of silicon as thermal neutron filter

Energy Technology Data Exchange (ETDEWEB)

Adib, M.; Habib, N.; Ashry, A.; Fathalla, M. E-mail: mohamedfathalla@hotmail.com

2003-12-01

A simple formula is given which allows to calculate the contribution of the total neutron cross-section including the Bragg scattering from different (hkl) planes to the neutron transmission through a solid crystalline silicon. The formula takes into account the silicon form of poly or mono crystals and its parameters. A computer program DSIC was developed to provide the required calculations. The calculated values of the total neutron cross-section of perfect silicon crystal at room and liquid nitrogen temperatures were compared with the experimental ones. The obtained agreement shows that the simple formula fits the experimental data with sufficient accuracy. A good agreement was also obtained between the calculated and measured values of polycrystalline silicon in the energy range from 5 eV to 500 {mu}eV. The feasibility study on using a poly-crystalline silicon as a cold neutron filter and mono-crystalline as a thermal neutron one is given. The optimum crystal thickness, mosaic spread, temperature and cutting plane for efficiently transmitting the thermal reactor neutrons, while rejecting both fast neutrons and gamma rays accompanying the thermal ones for the mono crystalline silicon are also given.

Development of a ten inch manipulators-based, flexible, broadband two-crystal spectrometer

Energy Technology Data Exchange (ETDEWEB)

Steel, A. B., E-mail: steel1@llnl.gov; Dunn, J.; Emig, J.; Beiersdorfer, P.; Brown, G. V.; Shepherd, R.; Marley, E. V. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Hoarty, D. J. [Atomic Weapons Establishment, Aldermaston (United Kingdom)

2014-11-15

We have developed and implemented a broadband X-ray spectrometer with a variable energy range for use at the Atomic Weapons Establishment's Orion Laser. The spectrometer covers an energy bandwidth of ∼1–2 keV using two independently mounted, movable Bragg diffraction crystals. Using combinations of cesium hydrogen pthlate, ammonium dihydrogen phosphate, and pentaerythritol crystals, spectra covering the 1.4–2.5, 1.85–3.15, or 3.55–5.1 keV energy bands have been measured. Image plate is used for detection owing to its high dynamic range. Background signals caused by high energy X-rays and particles commonly produced in high energy laser experiments are reduced by a series of tantalum baffles and filters installed between the source and crystal and also between the crystals and detector.

Protein-Nanocellulose Interactions in Paper Filters for Advanced Separation Applications.

Science.gov (United States)

Gustafsson, Simon; Manukyan, Levon; Mihranyan, Albert

2017-05-16

Protein-based pharmaceutics are widely explored for healthcare applications, and 6 out of 10 best-selling drugs today are biologicals. The goal of this work was to evaluate the protein nanocellulose interactions in paper filter for advanced separation applications such as virus removal filtration and bioprocessing. The protein recovery was measured for bovine serum albumin (BSA), γ-globulin, and lysozyme using biuret total protein reagent and polyacrylamide gel electrophoresis (PAGE), and the throughput was characterized in terms of flux values from fixed volume filtrations at various protein concentrations and under worst-case experimental conditions. The affinity of cellulose to bind various proteins, such as BSA, lysozyme, γ-globulin, and human IgG was quantified using a quartz crystal microbalance (QCMB) by developing a new method of fixing the cellulose fibers to the electrode surface without cellulose dissolution-precipitation. It was shown that the mille-feuille filter exhibits high protein recovery, that is, ∼99% for both BSA and lysozyme. However, γ-globulin does not pass through the membrane due to its large size (i.e., >180 kDa). The PAGE data show no substantial change in the amount of dimers and trimers before and after filtration. QCMB analysis suggests a low affinity between the nanocellulose surface and proteins. The nanocellulose-based filter exhibits desirable inertness as a filtering material intended for protein purification.

Overexpression, purification, crystallization and preliminary X-ray crystal analysis of Bacillus pallidusd-arabinose isomerase

International Nuclear Information System (INIS)

Takeda, Kosei; Yoshida, Hiromi; Takada, Goro; Izumori, Ken; Kamitori, Shigehiro

2008-01-01

Recombinant B. pallidusd-arabinose isomerase was crystallized and diffraction data were collected to 2.3 Å resolution. d-Arabinose isomerase catalyzes the isomerization of d-arabinose to d-ribulose. Bacillus pallidusd-arabinose isomerase has broad substrate specificity and can catalyze the isomerization of d-arabinose, l-fucose, l-xylose, l-galactose and d-altrose. Recombinant B. pallidusd-arabinose isomerase was overexpressed, purified and crystallized. A crystal of the enzyme was obtained by the sitting-drop method at room temperature and belonged to the orthorhombic space group P2 1 2 1 2, with unit-cell parameters a = 144.9, b = 127.9, c = 109.5 Å. Diffraction data were collected to 2.3 Å resolution

An approach for fixed coefficient RNS-based FIR filter

Science.gov (United States)

Srinivasa Reddy, Kotha; Sahoo, Subhendu Kumar

2017-08-01

In this work, an efficient new modular multiplication method for {2k-1, 2k, 2k+1-1} moduli set is proposed to implement a residue number system (RNS)-based fixed coefficient finite impulse response filter. The new multiplication approach reduces the number of partial products by using pre-loaded product block. The reduction in partial products with the proposed modular multiplication improves the clock frequency and reduces the area and power as compared with the conventional modular multiplication. Further, the present approach eliminates a binary number to residue number converter circuit, which is usually needed at the front end of RNS-based system. In this work, two fixed coefficient filter architectures with the new modular multiplication approach are proposed. The filters are implemented using Verilog hardware description language. The United Microelectronics Corporation 90 nm technology library has been used for synthesis and the results area, power and delay are obtained with the help of Cadence register transfer level compiler. The power delay product (PDP) is also considered for performance comparison among the proposed filters. One of the proposed architecture is found to improve PDP gain by 60.83% as compared with the filter implemented with conventional modular multiplier. The filters functionality is validated with the help of Altera DSP Builder.

Crystallization and preliminary X-ray diffraction study of phosphopantetheine adenylyltransferase from M. tuberculosis crystallizing in space group P3{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Timofeev, V. I., E-mail: tostars@mail.ru [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation); Chupova, L. A.; Esipov, R. S. [Russian Academy of Sciences, Shemyakin–Ovchinnikov Institute of Bioorganic Chemistry (Russian Federation); Kuranova, I. P. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)

2015-09-15

Crystals of M. tuberculosis phosphopantetheine adenylyltransferase were grown in microgravity by the capillary counter-diffusion method through a gel layer. The X-ray diffraction data set suitable for the determination of the three-dimensional structure at atomic resolution was collected from one crystal at the Spring-8 synchrotron facility to 2.00-Å resolution. The crystals belong to sp. gr. P3{sub 2} and have the following unit-cell parameters: a = b = 106.47 Å, c = 71.32 Å, α = γ = 90°, β = 120°. The structure was solved by the molecular-replacement method. There are six subunits of the enzyme comprising a hexamer per asymmetric unit. The hexamer is a biologically active form of phosphopantetheine adenylyltransferase from M. tuberculosis.

Numerical study of canister filters with alternatives filter cap configurations

Science.gov (United States)

Mohammed, A. N.; Daud, A. R.; Abdullah, K.; Seri, S. M.; Razali, M. A.; Hushim, M. F.; Khalid, A.

2017-09-01

Air filtration system and filter play an important role in getting a good quality air into turbo machinery such as gas turbine. The filtration system and filter has improved the quality of air and protect the gas turbine part from contaminants which could bring damage. During separation of contaminants from the air, pressure drop cannot be avoided but it can be minimized thus helps to reduce the intake losses of the engine [1]. This study is focused on the configuration of the filter in order to obtain the minimal pressure drop along the filter. The configuration used is the basic filter geometry provided by Salutary Avenue Manufacturing Sdn Bhd. and two modified canister filter cap which is designed based on the basic filter model. The geometries of the filter are generated by using SOLIDWORKS software and Computational Fluid Dynamics (CFD) software is used to analyse and simulates the flow through the filter. In this study, the parameters of the inlet velocity are 0.032 m/s, 0.063 m/s, 0.094 m/s and 0.126 m/s. The total pressure drop produce by basic, modified filter 1 and 2 is 292.3 Pa, 251.11 Pa and 274.7 Pa. The pressure drop reduction for the modified filter 1 is 41.19 Pa and 14.1% lower compared to basic filter and the pressure drop reduction for modified filter 2 is 17.6 Pa and 6.02% lower compared to the basic filter. The pressure drops for the basic filter are slightly different with the Salutary Avenue filter due to limited data and experiment details. CFD software are very reliable in running a simulation rather than produces the prototypes and conduct the experiment thus reducing overall time and cost in this study.

The Mu2e undoped CsI crystal calorimeter

Science.gov (United States)

Atanov, N.; Baranov, V.; Budagov, J.; Cervelli, F.; Colao, F.; Cordelli, M.; Corradi, G.; Davydov, Y. I.; Di Falco, S.; Diociaiuti, E.; Donati, S.; Donghia, R.; Echenard, B.; Giovannella, S.; Glagolev, V.; Grancagnolo, F.; Happacher, F.; Hitlin, D. G.; Martini, M.; Miscetti, S.; Miyashita, T.; Morescalchi, L.; Murat, P.; Pedreschi, E.; Pezzullo, G.; Porter, F.; Raffaelli, F.; Ricci, M.; Saputi, A.; Sarra, I.; Spinella, F.; Tassielli, G.; Tereshchenko, V.; Usubov, Z.; Zhu, R. Y.

2018-02-01

The Mu2e experiment at Fermilab will search for Charged Lepton Flavor Violating conversion of a muon to an electron in an atomic field. The Mu2e detector is composed of a tracker, an electromagnetic calorimeter and an external system, surrounding the solenoid, to veto cosmic rays. The calorimeter plays an important role to provide: a) excellent particle identification capabilities; b) a fast trigger filter; c) an easier tracker track reconstruction. Two disks, located downstream of the tracker, contain 674 pure CsI crystals each. Each crystal is read out by two arrays of UV-extended SiPMs. The choice of the crystals and SiPMs has been finalized after a thorough test campaign. A first small scale prototype consisting of 51 crystals and 102 SiPM arrays has been exposed to an electron beam at the BTF (Beam Test Facility) in Frascati. Although the readout electronics were not final, results show that the current design is able to meet the timing and energy resolution required by the Mu2e experiment.

Liquid-crystal laser optics: design, fabrication, and performance

International Nuclear Information System (INIS)

Jacobs, S.D.; Cerqua, K.A.; Marshall, K.L.; Schmid, A.; Guardalben, M.J.; Skerrett, K.J.

1988-01-01

We describe the development of laser optics utilizing liquid crystals. Devices discussed constitute passive optical elements for both low-power and high-power laser systems, operating in either the pulsed or cw mode. Designs and fabrication methods are given in detail for wave plates, circular polarizers, optical isolators, laser-blocking notch filters, and soft apertures. Performance data in the visible to near infrared show these devices to be useful alternatives to other technologies based on conventional glasses, crystals, or thin films. The issue of laser damage is examined on the basis of off-line threshold testing and daily use in OMEGA, the 24-beam Nd:glass laser system at the Laboratory for Laser Energetics. Results demonstrate that long-term survivability has been achieved

Silicon photonic crystal nanostructures for refractive index sensing

DEFF Research Database (Denmark)

Dorfner, Dominic; Hürlimann, T.; Zabel, T.

2008-01-01

The authors present the fabrication and optical investigation of Silicon on Insulator photonic crystal drop-filters for use as refractive index sensors. Two types of defect nanocavities (L3 and H1-r) are embedded between two W1 photonic crystal waveguides to evanescently route light at the cavity...... mode frequency between input and output waveguides. Optical characterization of the structures in air and various liquids demonstrate detectivities in excess of n=n = 0:018 and n=n = 0:006 for the H1-r and L3 cavities, respectively. The measured cavity-frequencies and detector refractive index...... responsivities are in good agreement with simulations, demonstrating that the method provides a background free transducer signal with frequency selective addressing of a specic area of the sensor chip....

Design considerations for a suboptimal Kalman filter

Science.gov (United States)

Difilippo, D. J.

1995-06-01

In designing a suboptimal Kalman filter, the designer must decide how to simplify the system error model without causing the filter estimation errors to increase to unacceptable levels. Deletion of certain error states and decoupling of error state dynamics are the two principal model simplifications that are commonly used in suboptimal filter design. For the most part, the decisions as to which error states can be deleted or decoupled are based on the designer's understanding of the physics of the particular system. Consequently, the details of a suboptimal design are usually unique to the specific application. In this paper, the process of designing a suboptimal Kalman filter is illustrated for the case of an airborne transfer-of-alignment (TOA) system used for synthetic aperture radar (SAR) motion compensation. In this application, the filter must continuously transfer the alignment of an onboard Doppler-damped master inertial navigation system (INS) to a strapdown navigator that processes information from a less accurate inertial measurement unit (IMU) mounted on the radar antenna. The IMU is used to measure spurious antenna motion during the SAR imaging interval, so that compensating phase corrections can be computed and applied to the radar returns, thereby presenting image degradation that would otherwise result from such motions. The principles of SAR are described in many references, for instance. The primary function of the TOA Kalman filter in a SAR motion compensation system is to control strapdown navigator attitude errors, and to a less degree, velocity and heading errors. Unlike a classical navigation application, absolute positional accuracy is not important. The motion compensation requirements for SAR imaging are discussed in some detail. This TOA application is particularly appropriate as a vehicle for discussing suboptimal filter design, because the system contains features that can be exploited to allow both deletion and decoupling of error

Chromatic aberrations correction for imaging spectrometer based on acousto-optic tunable filter with two transducers.

Science.gov (United States)

Zhao, Huijie; Wang, Ziye; Jia, Guorui; Zhang, Ying; Xu, Zefu

2017-10-02

The acousto-optic tunable filter (AOTF) with wide wavelength range and high spectral resolution has long crystal and two transducers. A longer crystal length leads to a bigger chromatic focal shift and the double-transducer arrangement induces angular mutation in diffracted beam, which increase difficulty in longitudinal and lateral chromatic aberration correction respectively. In this study, the two chromatic aberrations are analyzed quantitatively based on an AOTF optical model and a novel catadioptric dual-path configuration is proposed to correct both the chromatic aberrations. The test results exhibit effectiveness of the optical configuration for this type of AOTF-based imaging spectrometer.

The Effect of Chain Structures on the Crystallization Behavior and Membrane Formation of Poly(Vinylidene Fluoride Copolymers

Directory of Open Access Journals (Sweden)

Wenzhong Ma

2014-05-01

Full Text Available The crystallization behaviors of two copolymers of PVDF were studied, and the effect of copolymerized chains on the crystallization behavior was investigated. The results indicated that both copolymers had a lowered crystallization temperature and crystallinity. The crystallization rate was improved by the copolymer with symmetrical units in PVDF chains, but hindered by asymmetrical units, compared with the neat PVDF. The symmetrical units in PVDF chains favored the β-crystals with fiber-like structures. According to the solubility parameter rule, methyl salicylate (MS can be chosen as a diluent for PVDF copolymers. Both diluted systems had liquid-liquid (L-L regions in the phase diagrams, which was due to the lowered crystallization temperature.

Technical evaluation of RETS-required reports for Crystal River Nuclear Generating Plant, Unit 3, for 1983

International Nuclear Information System (INIS)

Magleby, E.H.; Young, T.E.

1985-01-01

A review was performed on the reports required by Federal regulations and the plant-specific Radiological Effluent Technical Specifications (RETS) for operations conducted at Florida Power Corporation's Crystal River Nuclear Plant, Unit 3, during 1983. The three periodic reports reviewed were (1) the Effluent and Waste Disposal Semiannual Report, January 1-June 30, 1983, (2) the Effluent and Waste Disposal Semiannual Report, July 1-December 31, 1983, and (3) the Annual Environmental Operating Report, Radiological, 1983. The principal review guidelines were the plant's specific RETS and NRC guidance given in NUREG-0133, ''Preparation of Radiological Effluent Technical Specifications for Nuclear Power Plants.'' The Licensee's submitted reports were found to be reasonably complete and consistent with the review guidelines

Headwater fish population responses to planting grass filter strips adjacent to channelized agricultural headwater streams

Science.gov (United States)

Grass filter strips are a widely used conservation practice in the Midwestern United States for reducing nutrient, pesticide, and sediment inputs into agricultural streams. Only a limited amount of information is available on the ecological effects of planting grass filter strips adjacent to channe...

Coronagraph Focal-Plane Phase Masks Based on Photonic Crystal Technology: Recent Progress and Observational Strategy

Science.gov (United States)

Murakami, Naoshi; Nishikawa, Jun; Sakamoto, Moritsugu; Ise, Akitoshi; Oka, Kazuhiko; Baba, Naoshi; Murakami, Hiroshi; Tamura, Motohide; Traub, Wesley A.; Mawet, Dimitri;

Study of loading/air back-pulse cleaning cycles on the performance of ceramic membrane filters

International Nuclear Information System (INIS)

Waggoner, Charles; Alderman, Steven; Parsons, Michael; Hogoncamp, Kristina; Alderman, Steven

2007-01-01

Available in abstract form only. Full text of publication follows: The most commonly identified threats to conventional glass fiber HEPA filter performance are moisture and rapid blinding of filters by smoke. Regenerable filter media composed of ceramics or sintered metal can be utilized as pre-filters to protect the more vulnerable glass fiber HEPA filters in the event of upset conditions. Additionally, used in a pre-filtering application, the use of these regenerable filters can potentially extend the lifetime of conventional units. A series of tests have been conducted using CeraMem ceramic membrane filters in an effort to evaluate their performance after repeated loading and air back pulse cleaning. This was done in an effort to access filter performance after repeated loading/cleaning cycles. The filters were loaded using a solid potassium chloride aerosol challenge. The filters were evaluated for pressure drop and filtering efficiency changes from one cleaning cycle to the next. Additionally, the particle size distribution of the aerosol penetrating the filters was measured. (authors)

Hardware Implementation of a Bilateral Subtraction Filter

Science.gov (United States)

Huertas, Andres; Watson, Robert; Villalpando, Carlos; Goldberg, Steven

2009-01-01

A bilateral subtraction filter has been implemented as a hardware module in the form of a field-programmable gate array (FPGA). In general, a bilateral subtraction filter is a key subsystem of a high-quality stereoscopic machine vision system that utilizes images that are large and/or dense. Bilateral subtraction filters have been implemented in software on general-purpose computers, but the processing speeds attainable in this way even on computers containing the fastest processors are insufficient for real-time applications. The present FPGA bilateral subtraction filter is intended to accelerate processing to real-time speed and to be a prototype of a link in a stereoscopic-machine- vision processing chain, now under development, that would process large and/or dense images in real time and would be implemented in an FPGA. In terms that are necessarily oversimplified for the sake of brevity, a bilateral subtraction filter is a smoothing, edge-preserving filter for suppressing low-frequency noise. The filter operation amounts to replacing the value for each pixel with a weighted average of the values of that pixel and the neighboring pixels in a predefined neighborhood or window (e.g., a 9 9 window). The filter weights depend partly on pixel values and partly on the window size. The present FPGA implementation of a bilateral subtraction filter utilizes a 9 9 window. This implementation was designed to take advantage of the ability to do many of the component computations in parallel pipelines to enable processing of image data at the rate at which they are generated. The filter can be considered to be divided into the following parts (see figure): a) An image pixel pipeline with a 9 9- pixel window generator, b) An array of processing elements; c) An adder tree; d) A smoothing-and-delaying unit; and e) A subtraction unit. After each 9 9 window is created, the affected pixel data are fed to the processing elements. Each processing element is fed the pixel value for

Social and Demographic Factors Influencing Inferior Vena Cava Filter Retrieval at a Single Institution in the United States

Energy Technology Data Exchange (ETDEWEB)

Smith, S. Christian, E-mail: csmith@aemrc.arizona.edu; Shanks, Candace, E-mail: Candace.Shanks@osumc.edu; Guy, Gregory, E-mail: Gregory.Guy@osumc.edu; Yang, Xiangyu, E-mail: Xiangyu.Yang@osumc.edu; Dowell, Joshua D., E-mail: Joshua.Dowell@osumc.edu [The Ohio State University Wexner Medical Center, Division of Interventional Radiology, Department of Radiology (United States)

2015-10-15

PurposeRetrievable inferior vena cava filters (IVCFs) are associated with long-term adverse events that have increased interest in improving filter retrieval rates. Determining the influential patient social and demographic factors affecting IVCF retrieval is important to personalize patient management strategies and attain optimal patient care.Materials and MethodsSeven-hundred and sixty-two patients were retrospectively studied who had a filter placed at our institution between January 2011 and November 2013. Age, gender, race, cancer history, distance to residence from retrieval institution, and insurance status were identified for each patient, and those receiving retrievable IVCFs were further evaluated for retrieval rate and time to retrieval.ResultsOf the 762 filters placed, 133 were permanent filters. Of the 629 retrievable filters placed, 406 met the inclusion criteria and were eligible for retrieval. Results revealed patients with Medicare were less likely to have their filters retrieved (p = 0.031). Older age was also associated with a lower likelihood of retrieval (p < 0.001) as was living further from the medical center (p = 0.027). Patients who were white and had Medicare were more likely than similarly insured black patients to have their filters retrieved (p = 0.024).ConclusionsThe retrieval rate of IVCFs was most influenced by insurance status, distance from the medical center, and age. Race was statistically significant only when combined with insurance status. The results of this study suggest that these patient groups may need closer follow-up in order to obtain optimal IVCF retrieval rates.

Social and Demographic Factors Influencing Inferior Vena Cava Filter Retrieval at a Single Institution in the United States

International Nuclear Information System (INIS)

Smith, S. Christian; Shanks, Candace; Guy, Gregory; Yang, Xiangyu; Dowell, Joshua D.

2015-01-01

PurposeRetrievable inferior vena cava filters (IVCFs) are associated with long-term adverse events that have increased interest in improving filter retrieval rates. Determining the influential patient social and demographic factors affecting IVCF retrieval is important to personalize patient management strategies and attain optimal patient care.Materials and MethodsSeven-hundred and sixty-two patients were retrospectively studied who had a filter placed at our institution between January 2011 and November 2013. Age, gender, race, cancer history, distance to residence from retrieval institution, and insurance status were identified for each patient, and those receiving retrievable IVCFs were further evaluated for retrieval rate and time to retrieval.ResultsOf the 762 filters placed, 133 were permanent filters. Of the 629 retrievable filters placed, 406 met the inclusion criteria and were eligible for retrieval. Results revealed patients with Medicare were less likely to have their filters retrieved (p = 0.031). Older age was also associated with a lower likelihood of retrieval (p < 0.001) as was living further from the medical center (p = 0.027). Patients who were white and had Medicare were more likely than similarly insured black patients to have their filters retrieved (p = 0.024).ConclusionsThe retrieval rate of IVCFs was most influenced by insurance status, distance from the medical center, and age. Race was statistically significant only when combined with insurance status. The results of this study suggest that these patient groups may need closer follow-up in order to obtain optimal IVCF retrieval rates

The 2D Hotelling filter - a quantitative noise-reducing principal-component filter for dynamic PET data, with applications in patient dose reduction

International Nuclear Information System (INIS)

Axelsson, Jan; Sörensen, Jens

2013-01-01

In this paper we apply the principal-component analysis filter (Hotelling filter) to reduce noise from dynamic positron-emission tomography (PET) patient data, for a number of different radio-tracer molecules. We furthermore show how preprocessing images with this filter improves parametric images created from such dynamic sequence. We use zero-mean unit variance normalization, prior to performing a Hotelling filter on the slices of a dynamic time-series. The Scree-plot technique was used to determine which principal components to be rejected in the filter process. This filter was applied to [ 11 C]-acetate on heart and head-neck tumors, [ 18 F]-FDG on liver tumors and brain, and [ 11 C]-Raclopride on brain. Simulations of blood and tissue regions with noise properties matched to real PET data, was used to analyze how quantitation and resolution is affected by the Hotelling filter. Summing varying parts of a 90-frame [ 18 F]-FDG brain scan, we created 9-frame dynamic scans with image statistics comparable to 20 MBq, 60 MBq and 200 MBq injected activity. Hotelling filter performed on slices (2D) and on volumes (3D) were compared. The 2D Hotelling filter reduces noise in the tissue uptake drastically, so that it becomes simple to manually pick out regions-of-interest from noisy data. 2D Hotelling filter introduces less bias than 3D Hotelling filter in focal Raclopride uptake. Simulations show that the Hotelling filter is sensitive to typical blood peak in PET prior to tissue uptake have commenced, introducing a negative bias in early tissue uptake. Quantitation on real dynamic data is reliable. Two examples clearly show that pre-filtering the dynamic sequence with the Hotelling filter prior to Patlak-slope calculations gives clearly improved parametric image quality. We also show that a dramatic dose reduction can be achieved for Patlak slope images without changing image quality or quantitation. The 2D Hotelling-filtering of dynamic PET data is a computer

Feasibility Study On Using Crystalline Lead As a Neutron and Gamma Ray Filter

International Nuclear Information System (INIS)

Adib, M.; Naguib, K.; Ashry, A.; Fathalla, M.

2000-01-01

A generalized formula is given which allows to calculate the contribution of the total neutron cross- section including the Bragg scattering from different (hkI) planes to the neutron transmission through a solid crystalline material. The formula takes into account the crystalline form of the material (poly- or mono- crystal ) and crystal parameters. A computer program ISCANF-II was developed to provide the required calculations. The calculated values of the neutron transmission through a lead single crystal cut along the (311) plane were compared with the previously measured ones in the wavelength range 0.03-0.52 nm. The measured and calculated values were found to be in reasonable agreement within the statistical accuracy. The feasibility study on using a poly crystalline lead as a cold neutron filter and monocrystalline as a thermal neutron one is given. The optimum crystal thickness, temperature and characteristics for efficiently transmitting the thermal reactor neutrons, while removing simultaneously fast neutrons and gamma rays accompanying the thermal ones for the both cases are given

Crystallization of Ulex europaeus lectin I.

Science.gov (United States)

Vandonselaar, M; Delbaere, L T

1994-10-21

The lectin I from Ulex europaeus (UEAI) has a strong affinity for the H-type 2 human blood group determinant. Single crystals of UEAI have been grown in the monoclinic crystal system. Initial crystals were obtained after 11 months from a solution of 10 mg/ml protein, 40% 2,4-methylpentanediol and 0.1 N acetate buffer at pH 5.2. The technique of washing and reseeding was used to generate large suitable crystals. The space group is C2 with a = 78.84 A, b = 69.85 A, c = 120.62 A, beta = 108.74 degrees and Z = 4; there is one molecular dimer per asymmetric unit and the solvent content is estimated to be 58%. The crystals diffract to at least 2.8 A d spacings and are stable in the X-ray beam for more than three days.

Crystallization and preliminary X-ray crystallographic analysis of recombinant β-mannosidase from Aspergillus niger

International Nuclear Information System (INIS)

Demo, Gabriel; Fliedrová, Barbora; Weignerová, Lenka; Wimmerová, Michaela

2013-01-01

β-Mannosidase from Aspergillus niger was crystallized in the presence of d-mannose and the crystal diffracted to 2.41 Å resolution. The crystal belonged to the space group P1 with unit-cell parameters a= 62.37, b = 69.73, c = 69.90 Å, α = 108.20, β = 101.51, γ = 103.20°. β-Mannosidase (EC 3.2.1.25) is an important exoglycosidase specific for the hydrolysis of terminal β-linked mannoside in various oligomeric saccharide structures. β-Mannosidase from Aspergillus niger was expressed in Pichia pastoris and purified to clear homogeneity. β-Mannosidase was crystallized in the presence of d-mannose and the crystal diffracted to 2.41 Å resolution. The crystal belonged to space group P1, with unit-cell parameters a = 62.37, b = 69.73, c = 69.90 Å, α = 108.20, β = 101.51, γ = 103.20°. The parameters derived from the data collection indicate the presence of one molecule in the asymmetric unit

Conservation of filtering in manufacturing systems with unreliable machines and finished goods buffers

Directory of Open Access Journals (Sweden)

2006-01-01

Full Text Available This paper addresses the issue of reliable satisfaction of customer demand by unreliable production systems. In the framework of a simple production-storage-customer model, we show that this can be accomplished by using an appropriate level of filtering of production randomness. The filtering is ensured by finished goods buffers (filtering in space and shipping periods (filtering in time. The following question is considered: how are filtering in space and filtering in time interrelated? As an answer, we show that there exists a conservation law: in lean manufacturing systems, the amount of filtering in space multiplied by the amount of filteringin time (both measured in appropriate dimensionless units ispractically constant. Along with providing an insight into the nature of manufacturing systems, this law offers a tool for selecting the smallest, that is, lean, finished goods buffering, which is necessary and sufficient to ensure the desired level ofcustomer demand satisfaction.

Logarithmic r-θ mapping for hybrid optical neural network filter for multiple objects recognition within cluttered scenes

Science.gov (United States)

Kypraios, Ioannis; Young, Rupert C. D.; Chatwin, Chris R.; Birch, Phil M.

2009-04-01

θThe window unit in the design of the complex logarithmic r-θ mapping for hybrid optical neural network filter can allow multiple objects of the same class to be detected within the input image. Additionally, the architecture of the neural network unit of the complex logarithmic r-θ mapping for hybrid optical neural network filter becomes attractive for accommodating the recognition of multiple objects of different classes within the input image by modifying the output layer of the unit. We test the overall filter for multiple objects of the same and of different classes' recognition within cluttered input images and video sequences of cluttered scenes. Logarithmic r-θ mapping for hybrid optical neural network filter is shown to exhibit with a single pass over the input data simultaneously in-plane rotation, out-of-plane rotation, scale, log r-θ map translation and shift invariance, and good clutter tolerance by recognizing correctly the different objects within the cluttered scenes. We record in our results additional extracted information from the cluttered scenes about the objects' relative position, scale and in-plane rotation.

Non-isothermal crystallization kinetics and characterization of biodegradable poly(butylene succinate-co-neopentyl glycol succinate) copolyesters

International Nuclear Information System (INIS)

Xie, Wen-Jie; Zhou, Xiao-Ming

2015-01-01

Both biodegradable aliphatic neat poly(butylene succinate) (PBS) and poly(butylene succinate-co-neopentyl glycol succinate) (P(BS-co-NPGS)) copolyesters with different 1,4-butanediol/neopentyl glycol ratios were synthesized through a two-step process of transesterification and polycondensation using stannous chloride and 4-Methylbenzenesulfonic acid as the co-catalysts. The structure, non-isothermal crystallization behavior, crystalline morphology and crystal structure of neat PBS and P(BS-co-NPGS) copolyesters were characterized by 1 H NMR, differential scanning calorimetry (DSC), polarized optical microscope (POM) and wide angle X-ray diffraction (WAXD), respectively. The Avrami equation modified by Jeziorny and Mo's method was employed to describe the non-isothermal crystallization kinetics of the neat PBS and its copolyesters. The modified Avrami equation could adequately describe the primary stage of non-isothermal crystallization kinetics of the neat PBS and its copolyesters. Mo's method provided a fairly satisfactory description of the non-isothermal crystallization of neat PBS and its copolyesters. Interestingly, the values of 1/t 1/2 , Z c and F(T) obtained by the modified Avrami equation and Mo's method analysis indicated that the crystallization rate increased first and then decreased with an increase of NPGS content compared that of neat PBS, whereas the crystallization mechanism almost kept unchanged. The results of tensile testing showed that the ductility of PBS was largely improved by incorporating NPGS units. The elongation at break increased remarkably with increasing NPGS content. In particular, the sample with 20% NPGS content showed around 548% elongation at break. - Highlights: • The incorporation of NPGS units reduced the spherulite size of BS unit. • The existence of NPGS units did not change the crystal structure of BS unit. • The NPGS units incorporated in PBS could significantly improve the ductility of PBS. • The

Controlling flow conditions of test filters in iodine filters

International Nuclear Information System (INIS)

Holmberg, R.; Laine, J.

1979-03-01

Several different iodine filter and test filter designs and experience gained from their operation are presented. For the flow experiments, an iodine filter system equipped with flow regulating and measuring devices was built. In the experiments the influence of the packing method of the iodine sorption material and the influence of the flow regulating and measuring divices upon the flow conditions in the test filters was studied. On the basis of the experiments it has been shown that the flows through the test filters always can be adjusted to a correct value if there only is a high enough pressure difference available across the test filter ducting. As a result of the research, several different methods are presented with which the flows through the test filters in both operating and future iodine sorption system can easily be measured and adjusted to their correct values. (author)

Spatial filter lens design for the main laser of the National Ignition Facility

International Nuclear Information System (INIS)

Korniski, R.J.

1998-01-01

The National Ignition Facility (NIF), being designed and constructed at Lawrence Livermore National Laboratory (LLNL), comprises 192 laser beams The lasing medium is neodymium in phosphate glass with a fundamental frequency (1ω) of 1 053microm Sum frequency generation in a pair of conversion crystals (KDP/KD*P) will produce 1 8 megajoules of the third harmonic light (3ω or λ=351microm) at the target The purpose of this paper is to provide the lens design community with the current lens design details of the large optics in the Main Laser This paper describes the lens design configuration and design considerations of the Main Laser The Main Laser is 123 meters long and includes two spatial filters one 13 5 meters and one 60 meters These spatial filters perform crucial beam filtering and relaying functions We shall describe the significant lens design aspects of these spatial filter lenses which allow them to successfully deliver the appropriate beam characteristic onto the target For an overview of NIF please see ''Optical system design of the National Ignition Facility,'' by R Edward English. et al also found in this volume

Design of an elliptic spot illumination system in LED-based color filter-liquid-crystal-on-silicon pico projectors for mobile embedded projection.

Science.gov (United States)

Chen, Enguo; Yu, Feihong

2012-06-01

We present an elliptic spot illumination system for a color filter-liquid-crystal-on-silicon (CF-LCoS) pico projector employing a specifically designed free-form lens and a cylindrical lens to improve on previous designs in terms of optical efficiency while yielding an ultracompact and low-cost optical architecture. The detailed design description of the optical system is thoroughly investigated. Simulation results coincide well with the theoretical calculation. The single 1  mm×1  mm LED chip-powered optical engine, which employs a CF-LCoS panel with a diagonal of 0.28 in and an aspect ratio of 4:3, has an estimated output efficiency over 9.8% (11.8 lm@1 W) and an ANSI 9-point uniformity over 88.5%, with the ultrasmall volume 24  mm×19  mm×7  mm. Compared to the circular spot-illuminated projection system, a total increment of about 23% of system efficiency is available with this improved optical engine. It is believed that there would be a huge market potential to commercialize our design.

Magnetophotorefractive effect and interference filters in lithium niobate

International Nuclear Information System (INIS)

Dam-Hansen, C.

1996-03-01

This thesis deals with the fundamental photorefractive and photovoltaic properties of iron-doped lithium niobate crystals. Experimental observations of a strong magnetic field effect on the energy coupling and grating formation in a vectorial interaction scheme are presented. To the author's knowledge these are the first reported results in the field. It is shown that an enhancement of the diffraction efficiency of 60% is possible by applying even a moderate magnetic field of 0.23 T. A new theoretical model of the magnetophotorefractive effect in the vectorial interaction scheme is presented. It describes the space-charge field formation, two-wave mixing and grating formation under the influence of an externally applied magnetic field. Good agreement with the experimental results and the first measurement of nondiagonal components of the magnetophotovoltaic tensor are reported. A theoretical model for the temperature properties of photorefractive interference filters with subangstrom bandwidths are presented and compared favourably with experimental investigations. A novel method for determining the spectral response of these filters from a combined thermal and angular response measurements is described. (au) 9 tabs., 30 ills., 84 refs

The Rao-Blackwellized Particle Filter: A Filter Bank Implementation

Directory of Open Access Journals (Sweden)

Karlsson Rickard

2010-01-01

Full Text Available For computational efficiency, it is important to utilize model structure in particle filtering. One of the most important cases occurs when there exists a linear Gaussian substructure, which can be efficiently handled by Kalman filters. This is the standard formulation of the Rao-Blackwellized particle filter (RBPF. This contribution suggests an alternative formulation of this well-known result that facilitates reuse of standard filtering components and which is also suitable for object-oriented programming. Our RBPF formulation can be seen as a Kalman filter bank with stochastic branching and pruning.

Crystallization and preliminary X-ray diffraction analysis of phosphoglycerate kinase from Streptococcus pneumoniae

International Nuclear Information System (INIS)

Bernardo-García, Noelia; Bartual, Sergio G.; Fulde, Marcus; Bergmann, Simone; Hermoso, Juan A.

2011-01-01

Phosphoglycerate kinase, a two-domain enzyme involved in the glycolytic pathway, has been crystallized. Both the N-terminal domain and a ternary complex of the full-length enzyme with substrates were crystallized by the sitting-drop vapour-diffusion method. Inclusion of the substrates was critical in order to obtain crystals of the full-length protein. Phosphoglycerate kinase (PGK) is a widespread two-domain enzyme that plays a critical role in the glycolytic pathway. Several glycolytic enzymes from streptococci have been identified as surface-exposed proteins that are involved in streptococcal virulence by their ability to bind host proteins. This binding allows pneumococcal cells to disseminate through the epithelial and endothelial layers. Crystallization of PGK from Streptococcus pneumoniae yielded orthorhombic crystals (space group I222, unit-cell parameters a = 62.73, b = 75.38, c = 83.63 Å). However, the unit cell of these crystals was not compatible with the presence of full-length PGK. Various analytical methods showed that only the N-terminal domain of PGK was present in the I222 crystals. The ternary complex of PGK with adenylyl imidodiphosphate (AMP-PNP) and 3-phospho-d-glycerate (3PGA) produced monoclinic crystals (space group P2 1 , unit-cell parameters a = 40.35, b = 78.23, c = 59.03 Å, β = 96.34°). Molecular replacement showed that this new crystal form contained full-length PGK, thereby indicating the relevance of including substrates in order to avoid proteolysis during the crystallization process

Convergent Filter Bases

Directory of Open Access Journals (Sweden)

Coghetto Roland

2015-09-01

Full Text Available We are inspired by the work of Henri Cartan [16], Bourbaki [10] (TG. I Filtres and Claude Wagschal [34]. We define the base of filter, image filter, convergent filter bases, limit filter and the filter base of tails (fr: filtre des sections.

Novel beam bunching methods by perfect crystals and electromagnetic means

International Nuclear Information System (INIS)

Rauch, H.

1985-01-01

The use of perfect crystals for installing new neutron small-angle scattering cameras provides advantages for measurements in the small Q-range and for real-time experiments. A neutron resonator is proposed which is based on the combination of perfect crystal back-reflections in Zeman energy splitting. The neutron magnetic resonance system in combination with gated crystals can act as a pumping unit for neutrons and as a new pulse-shaping unit. It is shown how travelling magnetic waves can act as powerful neutron bunching units. The achievable velocity changes are around 5 m/s and, therefore, by a factor of 100 larger than in the case of neutron magnetic resonance systems. The advantage of expanding potentials for focusing neutrons from a source with a long pulse duration becomes obvious. Real gain factors higher than 10 are expected for properly designed systems. (author)

Unidirectional Wave Propagation in Low-Symmetric Colloidal Photonic-Crystal Heterostructures

OpenAIRE

Yannopapas, Vassilios

2015-01-01

We show theoretically that photonic crystals consisting of colloidal spheres exhibit unidirectional wave propagation and one-way frequency band gaps without breaking time-reversal symmetry via, e.g., the application of an external magnetic field or the use of nonlinear materials. Namely, photonic crystals with low symmetry such as the monoclinic crystal type considered here as well as with unit cells formed by the heterostructure of different photonic crystals show significant unidirectional ...

Application of DFT Filter Banks and Cosine Modulated Filter Banks in Filtering

Science.gov (United States)

Lin, Yuan-Pei; Vaidyanathan, P. P.

1994-01-01

None given. This is a proposal for a paper to be presented at APCCAS '94 in Taipei, Taiwan. (From outline): This work is organized as follows: Sec. II is devoted to the construction of the new 2m channel under-decimated DFT filter bank. Implementation and complexity of this DFT filter bank are discussed therein. IN a similar manner, the new 2m channel cosine modulated filter bank is discussed in Sec. III. Design examples are given in Sec. IV.

Economical Implementation of a Filter Engine in an FPGA

Science.gov (United States)

Kowalski, James E.

2009-01-01

A logic design has been conceived for a field-programmable gate array (FPGA) that would implement a complex system of multiple digital state-space filters. The main innovative aspect of this design lies in providing for reuse of parts of the FPGA hardware to perform different parts of the filter computations at different times, in such a manner as to enable the timely performance of all required computations in the face of limitations on available FPGA hardware resources. The implementation of the digital state-space filter involves matrix vector multiplications, which, in the absence of the present innovation, would ordinarily necessitate some multiplexing of vector elements and/or routing of data flows along multiple paths. The design concept calls for implementing vector registers as shift registers to simplify operand access to multipliers and accumulators, obviating both multiplexing and routing of data along multiple paths. Each vector register would be reused for different parts of a calculation. Outputs would always be drawn from the same register, and inputs would always be loaded into the same register. A simple state machine would control each filter. The output of a given filter would be passed to the next filter, accompanied by a "valid" signal, which would start the state machine of the next filter. Multiple filter modules would share a multiplication/accumulation arithmetic unit. The filter computations would be timed by use of a clock having a frequency high enough, relative to the input and output data rate, to provide enough cycles for matrix and vector arithmetic operations. This design concept could prove beneficial in numerous applications in which digital filters are used and/or vectors are multiplied by coefficient matrices. Examples of such applications include general signal processing, filtering of signals in control systems, processing of geophysical measurements, and medical imaging. For these and other applications, it could be

On the use of bismuth as a neutron filter

CERN Document Server

Adib, M

2003-01-01

A formula is given which, for neutron energies in the range 10 sup - sup 4 crystals, at room and liquid nitrogen temperatures. A feasibility study for use of Bi in powdered form, as a cold neutron filter, is detailed in terms of the optimum Bi-single crystal thickness, mosaic spread, temperature and cutting plane for efficient transmission of thermal-reactor neutrons, and also for rejection of the accom...

On the use of bismuth as a neutron filter

Science.gov (United States)

Adib, M.; Kilany, M.

2003-02-01

A formula is given which, for neutron energies in the range 10 -4< E<10 eV, permits calculation of the nuclear capture, thermal diffuse and Bragg scattering cross-sections as a function of bismuth temperature and crystalline form. Computer programs have been developed which allow calculations for the Bi rhombohedral structure in its poly-crystalline form and its equivalent hexagonal close-packed structure. The calculated total neutron cross-sections for poly-crystalline Bi at different temperatures were compared with the measured values. An overall agreement is indicated between the formula fits and experimental data. Agreement was also obtained for values of Bi-single crystals, at room and liquid nitrogen temperatures. A feasibility study for use of Bi in powdered form, as a cold neutron filter, is detailed in terms of the optimum Bi-single crystal thickness, mosaic spread, temperature and cutting plane for efficient transmission of thermal-reactor neutrons, and also for rejection of the accompanying fast neutrons and gamma rays.

On the use of bismuth as a neutron filter

Energy Technology Data Exchange (ETDEWEB)

Adib, M.; Kilany, M. E-mail: kilany11@hotmail.com

2003-02-01

A formula is given which, for neutron energies in the range 10{sup -4}crystals, at room and liquid nitrogen temperatures. A feasibility study for use of Bi in powdered form, as a cold neutron filter, is detailed in terms of the optimum Bi-single crystal thickness, mosaic spread, temperature and cutting plane for efficient transmission of thermal-reactor neutrons, and also for rejection of the accompanying fast neutrons and gamma rays.

On the use of bismuth as a neutron filter

International Nuclear Information System (INIS)

Adib, M.; Kilany, M.

2003-01-01

A formula is given which, for neutron energies in the range 10 -4 < E<10 eV, permits calculation of the nuclear capture, thermal diffuse and Bragg scattering cross-sections as a function of bismuth temperature and crystalline form. Computer programs have been developed which allow calculations for the Bi rhombohedral structure in its poly-crystalline form and its equivalent hexagonal close-packed structure. The calculated total neutron cross-sections for poly-crystalline Bi at different temperatures were compared with the measured values. An overall agreement is indicated between the formula fits and experimental data. Agreement was also obtained for values of Bi-single crystals, at room and liquid nitrogen temperatures. A feasibility study for use of Bi in powdered form, as a cold neutron filter, is detailed in terms of the optimum Bi-single crystal thickness, mosaic spread, temperature and cutting plane for efficient transmission of thermal-reactor neutrons, and also for rejection of the accompanying fast neutrons and gamma rays

Digital timing: sampling frequency, anti-aliasing filter and signal interpolation filter dependence on timing resolution

International Nuclear Information System (INIS)

Cho, Sanghee; Grazioso, Ron; Zhang Nan; Aykac, Mehmet; Schmand, Matthias

2011-01-01

The main focus of our study is to investigate how the performance of digital timing methods is affected by sampling rate, anti-aliasing and signal interpolation filters. We used the Nyquist sampling theorem to address some basic questions such as what will be the minimum sampling frequencies? How accurate will the signal interpolation be? How do we validate the timing measurements? The preferred sampling rate would be as low as possible, considering the high cost and power consumption of high-speed analog-to-digital converters. However, when the sampling rate is too low, due to the aliasing effect, some artifacts are produced in the timing resolution estimations; the shape of the timing profile is distorted and the FWHM values of the profile fluctuate as the source location changes. Anti-aliasing filters are required in this case to avoid the artifacts, but the timing is degraded as a result. When the sampling rate is marginally over the Nyquist rate, a proper signal interpolation is important. A sharp roll-off (higher order) filter is required to separate the baseband signal from its replicates to avoid the aliasing, but in return the computation will be higher. We demonstrated the analysis through a digital timing study using fast LSO scintillation crystals as used in time-of-flight PET scanners. From the study, we observed that there is no significant timing resolution degradation down to 1.3 Ghz sampling frequency, and the computation requirement for the signal interpolation is reasonably low. A so-called sliding test is proposed as a validation tool checking constant timing resolution behavior of a given timing pick-off method regardless of the source location change. Lastly, the performance comparison for several digital timing methods is also shown.

Comparison of pre-filter and post-filter ionised calcium monitoring in continuous veno-venous hemodiafiltration (CVVHD-F with citrate anti-coagulation.

Directory of Open Access Journals (Sweden)

Matthew J Brain

Full Text Available It is widespread practice during citrate anticoagulated renal replacement therapy to monitor circuit ionised calcium (iCa2+ to evaluate the effectiveness of anticoagulation. Whether the optimal site to sample the blood path is before or after the haemofilter is a common question.Using a prospectively collected observational dataset from intensive care patients receiving pre-dilution continuous veno-venous haemodiafiltration (CVVHD-F with integrated citrate anticoagulation we compared paired samples of pre and post filter iCa2+ where the target range was 0.3-0.5 mmol.L-1 as well as concurrently collected arterial iCa2+. Two nested mixed methods linear models were fitted to the data describing post vs pre filter iCa2+, and the relationship of pre, post and arterial samples.An 11 bed general intensive care unit.450 grouped samples from 152 time periods in seven patients on CRRT with citrate anticoagulation.The relationship of post to pre-filter iCa2+ was not 1:1 with post = 0.082 + 0.751 x pre-filter iCa2+ (95% CI intercept: 0.015-0.152, slope 0.558-0.942. Variation was greatest between patients rather than between circuits within the same patient or citrate dose. Compared to arterial iCa2+ there was no significant difference between pre and post-filter sampling sites (F-value 0.047, p = 0.827.These results demonstrate that there is minimal difference between pre and post filter samples for iCa2+ monitoring of circuit anticoagulation in citrate patients relative to the arterial iCa2+ in CVVHD-F however compared to pre-filter sampling, post filter sampling has a flatter response and greater variation.

Recleaning of HEPA filters by reverse flow - evaluation of the underlying processes and the cleaning technique

International Nuclear Information System (INIS)

Leibold, H.; Leiber, T.; Doeffert, I.; Wilhelm, J.G.

1993-08-01

HEPA filter operation at high concentrations of fine dusts requires the periodic recleaning of the filter units in their service locations. Due to the low mechanical stress induced during the recleaning process the regenration via low pressure reverse flow is a very suitable technique. Recleanability of HEPA filter had been attained for particle diameter >0,4 μm at air velocities up to 1 m/s, but filter clogging occurred in case of smaller particles. The recleaning forces are too weak for particles [de

A Study of Parallel Operation of an active Filter and passive Filters

DEFF Research Database (Denmark)

Chen, Zhe; Blaabjerg, Frede; Pedersen, John Kim

2002-01-01

This paper reports investigations of the parallel operations of a current controlled active filter and passive filters in a system with current harmonic sources. The task of reactive power and harmonic compensation is shared by the active filter and passive filters. The passive filters are used...... arrangements of the active and passive filters can operate relatively independently, also the compensation flexibility of the active filter can be fully exploited, such as one active filter for several harmonic sources.The simulation studies on various systems have been performed to evaluate the effectiveness...... of the systems. The results show that the power factor is corrected by the passive filters, harmonics are minimized by both active and passive filters and overloading of the filter system can be avoided....

Conjugate gradient filtering of instantaneous normal modes, saddles on the energy landscape, and diffusion in liquids.

Science.gov (United States)

Chowdhary, J; Keyes, T

2002-02-01

Instantaneous normal modes (INM's) are calculated during a conjugate-gradient (CG) descent of the potential energy landscape, starting from an equilibrium configuration of a liquid or crystal. A small number (approximately equal to 4) of CG steps removes all the Im-omega modes in the crystal and leaves the liquid with diffusive Im-omega which accurately represent the self-diffusion constant D. Conjugate gradient filtering appears to be a promising method, applicable to any system, of obtaining diffusive modes and facilitating INM theory of D. The relation of the CG-step dependent INM quantities to the landscape and its saddles is discussed.

Passive Power Filters

CERN Document Server

Künzi, R.

2015-06-15

Power converters require passive low-pass filters which are capable of reducing voltage ripples effectively. In contrast to signal filters, the components of power filters must carry large currents or withstand large voltages, respectively. In this paper, three different suitable filter struc tures for d.c./d.c. power converters with inductive load are introduced. The formulas needed to calculate the filter components are derived step by step and practical examples are given. The behaviour of the three discussed filters is compared by means of the examples. P ractical aspects for the realization of power filters are also discussed.

Synthesis and Single Crystal X-Ray Structure Determination of 3,3',5 ...

African Journals Online (AJOL)

Single crystal structure determination at 100 K revealed needle-like crystals in an orthorhombic crystal system. The asymmetric unit of the cell consists of an isolated chloride ion, one half of a tetrahedral [MnCl4]2- anion, a [H2Me4bpz]2+ dication and one half of a molecule of water. Keywords: Crystal Engineering, Hydrogen ...

Deep Kalman Filter: Simultaneous Multi-Sensor Integration and Modelling; A GNSS/IMU Case Study.

Science.gov (United States)

Hosseinyalamdary, Siavash

2018-04-24

Bayes filters, such as the Kalman and particle filters, have been used in sensor fusion to integrate two sources of information and obtain the best estimate of unknowns. The efficient integration of multiple sensors requires deep knowledge of their error sources. Some sensors, such as Inertial Measurement Unit (IMU), have complicated error sources. Therefore, IMU error modelling and the efficient integration of IMU and Global Navigation Satellite System (GNSS) observations has remained a challenge. In this paper, we developed deep Kalman filter to model and remove IMU errors and, consequently, improve the accuracy of IMU positioning. To achieve this, we added a modelling step to the prediction and update steps of the Kalman filter, so that the IMU error model is learned during integration. The results showed our deep Kalman filter outperformed the conventional Kalman filter and reached a higher level of accuracy.

A two-step crushed lava rock filter unit for grey water treatment at household level in an urban slum.

Science.gov (United States)

Katukiza, A Y; Ronteltap, M; Niwagaba, C B; Kansiime, F; Lens, P N L

2014-01-15

Decentralised grey water treatment in urban slums using low-cost and robust technologies offers opportunities to minimise public health risks and to reduce environmental pollution caused by the highly polluted grey water i.e. with a COD and N concentration of 3000-6000 mg L(-1) and 30-40 mg L(-1), respectively. However, there has been very limited action research to reduce the pollution load from uncontrolled grey water discharge by households in urban slums. This study was therefore carried out to investigate the potential of a two-step filtration process to reduce the grey water pollution load in an urban slum using a crushed lava rock filter, to determine the main filter design and operation parameters and the effect of intermittent flow on the grey water effluent quality. A two-step crushed lava rock filter unit was designed and implemented for use by a household in the Bwaise III slum in Kampala city (Uganda). It was monitored at a varying hydraulic loading rate (HLR) of 0.5-1.1 m d(-1) as well as at a constant HLR of 0.39 m d(-1). The removal efficiencies of COD, TP and TKN were, respectively, 85.9%, 58% and 65.5% under a varying HLR and 90.5%, 59.5% and 69%, when operating at a constant HLR regime. In addition, the log removal of Escherichia coli, Salmonella spp. and total coliforms was, respectively, 3.8, 3.2 and 3.9 under the varying HLR and 3.9, 3.5 and 3.9 at a constant HLR. The results show that the use of a two-step filtration process as well as a lower constant HLR increased the pollutant removal efficiencies. Further research is needed to investigate the feasibility of adding a tertiary treatment step to increase the nutrients and microorganisms removal from grey water. Copyright © 2013 Elsevier Ltd. All rights reserved.

Bedside intravascular ultrasound-guided inferior vena cava filter placement in medical-surgical intensive care critically-ill patients

Directory of Open Access Journals (Sweden)

Mohammad A. Abusedera

2015-09-01

Conclusions: Bedside IVUS-guided filter placement in medical-surgical critically ill patient in intensive care unit is a feasible, safe and reliable technique for IVC interruption. IVUS may be the most appropriate tool to guide filter insertion in obese patient.

Crystallization and preliminary crystallographic analysis of molybdenum-cofactor biosynthesis protein C from Thermus thermophilus

International Nuclear Information System (INIS)

Kanaujia, Shankar Prasad; Ranjani, Chellamuthu Vasuki; Jeyakanthan, Jeyaraman; Baba, Seiki; Chen, Lirong; Liu, Zhi-Jie; Wang, Bi-Cheng; Nishida, Masami; Ebihara, Akio; Shinkai, Akeo; Kuramitsu, Seiki; Shiro, Yoshitsugu; Sekar, Kanagaraj; Yokoyama, Shigeyuki

2006-01-01

The molybdenum-cofactor biosynthesis protein C from T. thermophilus has been crystallized in two different space groups, P2 1 and R32; the crystals diffracted to 1.9 and 1.75 Å resolution, respectively. The Gram-negative aerobic eubacterium Thermus thermophilus is an extremely important thermophilic microorganism that was originally isolated from a thermal vent environment in Japan. The molybdenum cofactor in this organism is considered to be an essential component required by enzymes that catalyze diverse key reactions in the global metabolism of carbon, nitrogen and sulfur. The molybdenum-cofactor biosynthesis protein C derived from T. thermophilus was crystallized in two different space groups. Crystals obtained using the first crystallization condition belong to the monoclinic space group P2 1 , with unit-cell parameters a = 64.81, b = 109.84, c = 115.19 Å, β = 104.9°; the crystal diffracted to a resolution of 1.9 Å. The other crystal form belonged to space group R32, with unit-cell parameters a = b = 106.57, c = 59.25 Å, and diffracted to 1.75 Å resolution. Preliminary calculations reveal that the asymmetric unit contains 12 monomers and one monomer for the crystals belonging to space group P2 1 and R32, respectively

Efficient decoding with steady-state Kalman filter in neural interface systems.

Science.gov (United States)

Malik, Wasim Q; Truccolo, Wilson; Brown, Emery N; Hochberg, Leigh R

2011-02-01

The Kalman filter is commonly used in neural interface systems to decode neural activity and estimate the desired movement kinematics. We analyze a low-complexity Kalman filter implementation in which the filter gain is approximated by its steady-state form, computed offline before real-time decoding commences. We evaluate its performance using human motor cortical spike train data obtained from an intracortical recording array as part of an ongoing pilot clinical trial. We demonstrate that the standard Kalman filter gain converges to within 95% of the steady-state filter gain in 1.5±0.5 s (mean ±s.d.). The difference in the intended movement velocity decoded by the two filters vanishes within 5 s, with a correlation coefficient of 0.99 between the two decoded velocities over the session length. We also find that the steady-state Kalman filter reduces the computational load (algorithm execution time) for decoding the firing rates of 25±3 single units by a factor of 7.0±0.9. We expect that the gain in computational efficiency will be much higher in systems with larger neural ensembles. The steady-state filter can thus provide substantial runtime efficiency at little cost in terms of estimation accuracy. This far more efficient neural decoding approach will facilitate the practical implementation of future large-dimensional, multisignal neural interface systems.

Particle Kalman Filtering: A Nonlinear Bayesian Framework for Ensemble Kalman Filters*

KAUST Repository

Hoteit, Ibrahim

2012-02-01

This paper investigates an approximation scheme of the optimal nonlinear Bayesian filter based on the Gaussian mixture representation of the state probability distribution function. The resulting filter is similar to the particle filter, but is different from it in that the standard weight-type correction in the particle filter is complemented by the Kalman-type correction with the associated covariance matrices in the Gaussian mixture. The authors show that this filter is an algorithm in between the Kalman filter and the particle filter, and therefore is referred to as the particle Kalman filter (PKF). In the PKF, the solution of a nonlinear filtering problem is expressed as the weighted average of an “ensemble of Kalman filters” operating in parallel. Running an ensemble of Kalman filters is, however, computationally prohibitive for realistic atmospheric and oceanic data assimilation problems. For this reason, the authors consider the construction of the PKF through an “ensemble” of ensemble Kalman filters (EnKFs) instead, and call the implementation the particle EnKF (PEnKF). It is shown that different types of the EnKFs can be considered as special cases of the PEnKF. Similar to the situation in the particle filter, the authors also introduce a resampling step to the PEnKF in order to reduce the risk of weights collapse and improve the performance of the filter. Numerical experiments with the strongly nonlinear Lorenz-96 model are presented and discussed.

Isolation, crystallization and crystal structure determination of bovine kidney Na(+),K(+)-ATPase.

Science.gov (United States)

Gregersen, Jonas Lindholt; Mattle, Daniel; Fedosova, Natalya U; Nissen, Poul; Reinhard, Linda

2016-04-01

Na(+),K(+)-ATPase is responsible for the transport of Na(+) and K(+) across the plasma membrane in animal cells, thereby sustaining vital electrochemical gradients that energize channels and secondary transporters. The crystal structure of Na(+),K(+)-ATPase has previously been elucidated using the enzyme from native sources such as porcine kidney and shark rectal gland. Here, the isolation, crystallization and first structure determination of bovine kidney Na(+),K(+)-ATPase in a high-affinity E2-BeF3(-)-ouabain complex with bound magnesium are described. Crystals belonging to the orthorhombic space group C2221 with one molecule in the asymmetric unit exhibited anisotropic diffraction to a resolution of 3.7 Å with full completeness to a resolution of 4.2 Å. The structure was determined by molecular replacement, revealing unbiased electron-density features for bound BeF3(-), ouabain and Mg(2+) ions.

Rectifier Filters

Directory of Open Access Journals (Sweden)

Y. A. Bladyko

2010-01-01

Full Text Available The paper contains definition of a smoothing factor which is suitable for any rectifier filter. The formulae of complex smoothing factors have been developed for simple and complex passive filters. The paper shows conditions for application of calculation formulae and filters. 

Producing KDP and DKDP crystals for the NIF laser

International Nuclear Information System (INIS)

Atherton, L. J.; Burnham, A. K.; Combs, R. C.; Couture, S. A.; De Yoreo, J. J.; Hawley-Fedder, R. A.; Montesant, R. C.; Robey, H. F.; Runkel, M.; Staggs, M.; Wegner, P. J.; Yan, M.; Zaitseva, N. P.

1999-01-01

The cost and physics requirements of the NIF have established two important roles for potassium dihydrogen phosphate (KDP) crystals. 1. To extract more laser energy per unit of flashlamp light and laser glass, the NIF has adopted a multipass architecture as shown in Figure 1. Light is injected in the transport spatial filter, first traverses the power amplifiers, and then is directed to main amplifiers, where it makes four passes before being redirected through the power amplifiers towards the target. To enable the multipass of the main amplifiers, a KDP-containing Pockels cell rotates the polarization of the beam to make it either transmit through or reflect off a polarizer held at Brewster's angle within the main laser cavity. If transmitted, the light reflects off a mirror and makes another pass through the cavity. If reflected, it proceeds through the power amplifier to the target. the original seed crystal as the pyramid faces grow. Unfortunately, this pyramidal growth is very slow, and it takes about two years to grow a crystal to NIF size. To provide more programmatic flexibility and reduce costs in the long run, we have developed an alternative technology commonly called rapid growth. Through a combination of higher temperatures and higher supersaturation of the growth solution, a NIF-size boule can be grown in 1 to 2 months from a small ''point'' seed. However, growing boules of adequate size is not sufficient. Care must be taken to prevent inclusions of growth solution and incorporation of atomically substituted 2. Implosions for ICF work far better at shorter wavelengths due to less generation of hot electrons, which preheat the fuel and make it harder to compress. Compromising between optic lifetime and implosion efficiency, both Nova and the NIF operate at a tripled frequency of the 1053-nm fundamental frequency of a neodymium glass laser. This tripling is accomplished by two crystals, one made of KDP and one made of deuterated KDP (DKDP). The first

Socio-economic impacts of nuclear generating stations: Crystal River Unit 3 case study

International Nuclear Information System (INIS)

Bergmann, P.A.

1982-07-01

This report documents a case study of the socio-economic impacts of the construction and operation of the Crystal River Unit 3 nuclear power station. It is part of a major post-licensing study of the socio-economic impacts at twelve nuclear power stations. The case study covers the period beginning with the announcement of plans to construct the reactor and ending in the period 1980 to 1981. The case study deals with changes in the economy, population, settlement patterns and housing, local government and public services, social structure, and public response in the study area during the construction/operation of the reactor. A regional modeling approach is used to trace the impact of construction/operation on the local economy, labor market, and housing market. Emphasis in the study is on the attribution of socio-economic impacts to the reactor or other causal factors. As part of the study of local public response to the construction/operation of the reactor, the effects of the Three Mile Island accident are examined

Crystallization and preliminary characterization of dihydropteridine reductase from Dictyostelium discoideum

International Nuclear Information System (INIS)

Chen, Cong; Seo, Kyung Hye; Kim, Hye Lim; Zhuang, Ningning; Park, Young Shik; Lee, Kon Ho

2008-01-01

The dihydropteridine reductase from D. discoideum has been crystallized. Diffraction data were collected from a rectangular-shaped crystal to 2.16 Å resolution. Dihydropteridine reductase from Dictyostelium discoideum (dicDHPR) can produce d-threo-BH 4 [6R-(1′R,2′R)-5,6,7,8-tetrahydrobiopterin], a stereoisomer of l-erythro-BH 4 , in the last step of tetrahydrobiopterin (BH 4 ) recycling. In this reaction, DHPR uses NADH as a cofactor to reduce quinonoid dihydrobiopterin back to BH 4 . To date, the enzyme has been purified to homogeneity from many sources. In this report, the dicDHPR–NAD complex has been crystallized using the hanging-drop vapour-diffusion method with PEG 3350 as a precipitant. Rectangular-shaped crystals were obtained. Crystals grew to maximum dimensions of 0.4 × 0.6 × 0.1 mm. The crystal belonged to space group P2 1 , with unit-cell parameters a = 49.81, b = 129.90, c = 78.76 Å, β = 100.00°, and contained four molecules in the asymmetric unit, forming two closely interacting dicDHPR–NAD dimers. Diffraction data were collected to 2.16 Å resolution using synchrotron radiation. The crystal structure has been determined using the molecular-replacement method

Construction of crystal structure prototype database: methods and applications.

Science.gov (United States)

Su, Chuanxun; Lv, Jian; Li, Quan; Wang, Hui; Zhang, Lijun; Wang, Yanchao; Ma, Yanming

2017-04-26

Crystal structure prototype data have become a useful source of information for materials discovery in the fields of crystallography, chemistry, physics, and materials science. This work reports the development of a robust and efficient method for assessing the similarity of structures on the basis of their interatomic distances. Using this method, we proposed a simple and unambiguous definition of crystal structure prototype based on hierarchical clustering theory, and constructed the crystal structure prototype database (CSPD) by filtering the known crystallographic structures in a database. With similar method, a program structure prototype analysis package (SPAP) was developed to remove similar structures in CALYPSO prediction results and extract predicted low energy structures for a separate theoretical structure database. A series of statistics describing the distribution of crystal structure prototypes in the CSPD was compiled to provide an important insight for structure prediction and high-throughput calculations. Illustrative examples of the application of the proposed database are given, including the generation of initial structures for structure prediction and determination of the prototype structure in databases. These examples demonstrate the CSPD to be a generally applicable and useful tool for materials discovery.

Construction of crystal structure prototype database: methods and applications

International Nuclear Information System (INIS)

Su, Chuanxun; Lv, Jian; Wang, Hui; Wang, Yanchao; Ma, Yanming; Li, Quan; Zhang, Lijun

2017-01-01

Crystal structure prototype data have become a useful source of information for materials discovery in the fields of crystallography, chemistry, physics, and materials science. This work reports the development of a robust and efficient method for assessing the similarity of structures on the basis of their interatomic distances. Using this method, we proposed a simple and unambiguous definition of crystal structure prototype based on hierarchical clustering theory, and constructed the crystal structure prototype database (CSPD) by filtering the known crystallographic structures in a database. With similar method, a program structure prototype analysis package (SPAP) was developed to remove similar structures in CALYPSO prediction results and extract predicted low energy structures for a separate theoretical structure database. A series of statistics describing the distribution of crystal structure prototypes in the CSPD was compiled to provide an important insight for structure prediction and high-throughput calculations. Illustrative examples of the application of the proposed database are given, including the generation of initial structures for structure prediction and determination of the prototype structure in databases. These examples demonstrate the CSPD to be a generally applicable and useful tool for materials discovery. (paper)

Crystallization and preliminary crystallographic analysis of l-asparaginase from Erwinia carotovora

International Nuclear Information System (INIS)

Wikman, Linnea E. K.; Krasotkina, Julya; Kuchumova, Anastasia; Sokolov, Nikolay N.; Papageorgiou, Anastassios C.

2005-01-01

Er. carotovoral-asparaginase, a potential antileukaemic agent, has been crystallized. Crystals diffract to 2.6 Å using a rotating-anode source and belong to space group P2 1 , with unit-cell parameters a = 78.0, b = 112.3, c = 78.7 Å, β = 101.9° and a homotetramer in the crystallographic asymmetric unit. Bacterial l-asparaginases have been used as therapeutic agents in the treatment of acute childhood lymphoblastic leukaemia for over 30 y. However, their use is limited owing to the glutaminase activity of the administered enzymes, which results in serious side effects. In contrast, l-asparaginase from Erwinia carotovora exhibits low glutaminase activity at physiological concentrations of l-asparagine and l-glutamine in the blood. Recombinant Er. carotovoral-asparaginase was crystallized in the presence of l-glutamate by the hanging-drop vapour-diffusion method using 10 mg ml −1 purified enzyme, 16–18%(w/v) PEG 3350 and 0.2 M NaF. X-ray diffraction data were collected to 2.6 Å at 293 K using an in-house rotating-anode generator. The crystals belong to the monoclinic P2 1 space group, with unit-cell parameters a = 78.0, b = 112.3, c = 78.7 Å, β = 101.9° and a homotetramer in the crystallographic asymmetric unit. A molecular-replacement solution has been found and refinement is currently in progress. The crystal structure may provide leads towards protein-engineering efforts aimed at safer asparaginase administration in leukaemia treatment

Comparison of filters: Inkjet printed on PEN substrate versus a laser-etched on LCP substrate

KAUST Repository

Arabi, Eyad A.

2014-10-01

In this paper, microstrip-based bandpass filters on polyethylene naphthalate (PEN) and liquid crystal polymers (LCP) are presented to investigate the performance of filters on ultra-thin substrates. PEN (with a thickness of 120 μm) has been characterized and used for a filter for the first time. In addition to being low cost and transparent, it demonstrates comparable RF performance to LCP. The conductor losses are compared by fabricating filters with inkjet printed lines as well as laser etched copper clad LCP sheets. With 5 layers of inkjet printing, and a curing temperature below 200°C, a final silver thickness of 2 μm and conductivity of 9.6 × 106 S/m are achieved. The designs are investigated at two frequencies, 24 GHz as well as 5 GHz to assess their performance at high and low frequencies respectively. The 24 GHz inkjet printed filter shows an insertion loss of 2 dB, while the 5 GHz design gives an insertion loss of 8 dB. We find that thin substrates have a strong effect on the insertion loss of filters especially as the frequency is reduced. The same design, realized on LCP (thickness of 100 μm) through laser etching, demonstrates a very similar performance, thus verifying this finding. © 2014 European Microwave Association.

Comparison of filters: Inkjet printed on PEN substrate versus a laser-etched on LCP substrate

KAUST Repository

Arabi, Eyad A.; McKerricher, Garret; Shamim, Atif

2014-01-01

In this paper, microstrip-based bandpass filters on polyethylene naphthalate (PEN) and liquid crystal polymers (LCP) are presented to investigate the performance of filters on ultra-thin substrates. PEN (with a thickness of 120 μm) has been characterized and used for a filter for the first time. In addition to being low cost and transparent, it demonstrates comparable RF performance to LCP. The conductor losses are compared by fabricating filters with inkjet printed lines as well as laser etched copper clad LCP sheets. With 5 layers of inkjet printing, and a curing temperature below 200°C, a final silver thickness of 2 μm and conductivity of 9.6 × 106 S/m are achieved. The designs are investigated at two frequencies, 24 GHz as well as 5 GHz to assess their performance at high and low frequencies respectively. The 24 GHz inkjet printed filter shows an insertion loss of 2 dB, while the 5 GHz design gives an insertion loss of 8 dB. We find that thin substrates have a strong effect on the insertion loss of filters especially as the frequency is reduced. The same design, realized on LCP (thickness of 100 μm) through laser etching, demonstrates a very similar performance, thus verifying this finding. © 2014 European Microwave Association.

British Society of Interventional Radiology (BSIR) Inferior Vena Cava (IVC) Filter Registry

International Nuclear Information System (INIS)

Uberoi, Raman; Tapping, Charles Ross; Chalmers, Nicholas; Allgar, Victoria

2013-01-01

Purpose: The British Society of Interventional Radiology (BSIR) Inferior Vena Cava (IVC) Filter Registry was produced to provide an audit of current United Kingdom (UK) practice regarding placement and retrieval of IVC filters to address concerns regarding their safety. Methods: The IVC filter registry is a web-based registry, launched by the BSIR on behalf of its membership in October 2007. This report is based on prospectively collected data from October 2007 to March 2011. This report contains analysis of data on 1,434 IVC filter placements and 400 attempted retrievals performed at 68 UK centers. Data collected included patient demographics, insertion and retrieval data, and patient follow-up. Results: IVC filter use in the majority of patients in the UK follows accepted CIRSE guidelines. Filter placement is usually a low-risk procedure, with a low major complication rate ( 9 weeks versus those with a shorter dwell time. New lower limb deep vein thrombosis (DVT) and/or IVC thrombosis was reported in 88 patients following filter placement, there was no significant difference of incidence between filter types. Conclusions: This registry report provides interventional radiologists and clinicians with an improved understanding of the technical aspects of IVC filter placement to help improve practice, and the potential consequences of IVC filter placement so that we are better able to advise patients. There is a significant learning curve associated with IVC filter insertion, and when a filter is placed with the intention of removal, procedures should be in place to avoid the patient being lost to follow-up

Fast high-pressure freezing of protein crystals in their mother liquor

International Nuclear Information System (INIS)

Burkhardt, Anja; Warmer, Martin; Panneerselvam, Saravanan; Wagner, Armin; Zouni, Athina; Glöckner, Carina; Reimer, Rudolph; Hohenberg, Heinrich; Meents, Alke

2012-01-01

Protein crystals were vitrified using high-pressure freezing in their mother liquor at 210 MPa and 77 K without cryoprotectants or oil coating. The method was successfully applied to photosystem II, which is representative of a membrane protein with a large unit cell and weak crystal contacts. High-pressure freezing (HPF) is a method which allows sample vitrification without cryoprotectants. In the present work, protein crystals were cooled to cryogenic temperatures at a pressure of 210 MPa. In contrast to other HPF methods published to date in the field of cryocrystallography, this protocol involves rapid sample cooling using a standard HPF device. The fast cooling rates allow HPF of protein crystals directly in their mother liquor without the need for cryoprotectants or external reagents. HPF was first attempted with hen egg-white lysozyme and cubic insulin crystals, yielding good to excellent diffraction quality. Non-cryoprotected crystals of the membrane protein photosystem II have been successfully cryocooled for the first time. This indicates that the presented HPF method is well suited to the vitrification of challenging systems with large unit cells and weak crystal contacts

Crystallization of Δ1-tetrahydrocannabinolic acid (THCA) synthase from Cannabis sativa

International Nuclear Information System (INIS)

Shoyama, Yoshinari; Takeuchi, Ayako; Taura, Futoshi; Tamada, Taro; Adachi, Motoyasu; Kuroki, Ryota; Shoyama, Yukihiro; Morimoto, Satoshi

2005-01-01

Δ 1 -Tetrahydrocannabinolic acid (THCA) synthase from C. sativa was crystallized. The crystal diffracted to 2.7 Å resolution with sufficient quality for further structure determination. Δ 1 -Tetrahydrocannabinolic acid (THCA) synthase is a novel oxidoreductase that catalyzes the biosynthesis of the psychoactive compound THCA in Cannabis sativa (Mexican strain). In order to investigate the structure–function relationship of THCA synthase, this enzyme was overproduced in insect cells, purified and finally crystallized in 0.1 M HEPES buffer pH 7.5 containing 1.4 M sodium citrate. A single crystal suitable for X-ray diffraction measurement was obtained in 0.09 M HEPES buffer pH 7.5 containing 1.26 M sodium citrate. The crystal diffracted to 2.7 Å resolution at beamline BL41XU, SPring-8. The crystal belonged to the primitive cubic space group P432, with unit-cell parameters a = b = c = 178.2 Å. The calculated Matthews coefficient was approximately 4.1 or 2.0 Å 3 Da −1 assuming the presence of one or two molecules of THCA synthase in the asymmetric unit, respectively

Influence factors of photocatalytic activity of the filter media modified by TiO2

Directory of Open Access Journals (Sweden)

Shen Rongyan

2014-01-01

Full Text Available The gangue filter media was modified by the titanium dioxide (TiO2 through the liquid phase deposition method. Some influence factors of photocatalytic activity were investigated, including the mole ratio of initial solution, the water bath temperature, the deposition time, the calcination temperature, and the heat preservation time of calcination. The morphology of the film was examined by SEM, EDS, and crystallite structure by X-Ray Diffraction (XRD. The SEM, EDS, and XRD data showed that new TiO2 crystal was found in the modified filter media. And the specific surface area of the modified filter media greatly increased. By the orthogonal experiment, the optimum parameters of modification were (NH42TiF6:H3BO3=1:2, water bath temperature of 80ºC, deposition time of 5h, calcination temperature of 500ºC, and 1h heat preservation time of calcination. Under above conditions, the heavy nitrogen wastewater of 1589.94 mg/L COD and 18750 times chroma was treated by the modified filter media. After 1h catalytic reaction, the decolorization rate and COD removal rate reached 65.89% and 47.87%, respectively.

Retina-Inspired Filter.

Science.gov (United States)

Doutsi, Effrosyni; Fillatre, Lionel; Antonini, Marc; Gaulmin, Julien

2018-07-01

This paper introduces a novel filter, which is inspired by the human retina. The human retina consists of three different layers: the Outer Plexiform Layer (OPL), the inner plexiform layer, and the ganglionic layer. Our inspiration is the linear transform which takes place in the OPL and has been mathematically described by the neuroscientific model "virtual retina." This model is the cornerstone to derive the non-separable spatio-temporal OPL retina-inspired filter, briefly renamed retina-inspired filter, studied in this paper. This filter is connected to the dynamic behavior of the retina, which enables the retina to increase the sharpness of the visual stimulus during filtering before its transmission to the brain. We establish that this retina-inspired transform forms a group of spatio-temporal Weighted Difference of Gaussian (WDoG) filters when it is applied to a still image visible for a given time. We analyze the spatial frequency bandwidth of the retina-inspired filter with respect to time. It is shown that the WDoG spectrum varies from a lowpass filter to a bandpass filter. Therefore, while time increases, the retina-inspired filter enables to extract different kinds of information from the input image. Finally, we discuss the benefits of using the retina-inspired filter in image processing applications such as edge detection and compression.

A Data Quality Filter for PMU Measurements: Description, Experience, and Examples

Energy Technology Data Exchange (ETDEWEB)

Follum, James D.; Amidan, Brett G.

2016-07-17

Networks of phasor measurement units (PMUs) continue to grow, and along with them, the amount of data available for analysis. With so much data, it is impractical to identify and remove poor quality data manually. The data quality filter described in this paper was developed for use with the Data Integrity and Situation Awareness Tool (DISAT), which analyzes PMU data to identify anomalous system behavior. The filter operates based only on the information included in the data files, without supervisory control and data acquisition (SCADA) data, state estimator values, or system topology information. Measurements are compared to preselected thresholds to determine if they are reliable. Along with the filter's description, examples of data quality issues from application of the filter to nine months of archived PMU data are provided. The paper is intended to aid the reader in recognizing and properly addressing data quality issues in PMU data.

Performance Evaluation of Two Different Industrial Foam Filters with LiMCA II Data

Science.gov (United States)

Syvertsen, Martin; Bao, Sarina

2015-04-01

Plant-scale filtration experiments with molten aluminum have been carried out with two different types of 10 × 10 × 2 in, 30 ppi ceramic foam filters. The filters were produced in the same production line where the only difference was the composition of the ceramic slurry used for the filter production. The inclusion contents in the aluminum melt before and after the filters were measured with two constantly running liquid metal cleanliness analyzer (LiMCA) II units. Three methods for analyzing the recorded data are presented. A significant difference in the filtration performance as function of time was found when settling of inclusions in the melt was taken into account. Statistical treatment of the time dependent LiMCA II data was performed.

A high temperature superconductor notch filter for the Sardinia Radio Telescope

Science.gov (United States)

Bolli, Pietro; Cresci, Luca; Huang, Frederick; Mariotti, Sergio; Panella, Dario

2018-04-01

A High Temperature Superconductor filter operating in the C-band between 4200 and 5600 MHz has been developed for one of the radio astronomical receivers of the Sardinia Radio Telescope. The motivation was to attenuate an interference from a weather radar at 5640 MHz, whose power level exceeds the linear region of the first active stages of the receiver. A very sharp transition after the nominal maximum passband frequency is reached by combining a 6th order band-pass filter with a 6th order stop-band. This solution is competitive with an alternative layout based on a cascaded triplet filter. Three units of the filter have been measured with two different calibration approaches to investigate pros and cons of each, and data repeatability. The final performance figures of the filters are: ohmic losses of the order of 0.15-0.25 dB, matching better than -15 dB, and -30 dB attenuation at 5640 MHz. Finally, a more accurate model of the connection between external connector and microstrip shows a better agreement between simulations and experimental data.

Thickness filters for gradient based multi-material and thickness optimization of laminated composite structures

DEFF Research Database (Denmark)

Sørensen, Rene; Lund, Erik

2015-01-01

This paper presents a new gradient based method for performing discrete material and thickness optimization of laminated composite structures. The novelty in the new method lies in the application of so-called casting constraints, or thickness filters in this context, to control the thickness...... variation throughout the laminate. The filters replace the layerwise density variables with a single continuous through-the-thickness design variable. Consequently, the filters eliminate the need for having explicit constraints for preventing intermediate void through the thickness of the laminate....... Therefore, the filters reduce both the number of constraints and design variables in the optimization problem. Based upon a continuous approximation of a unit step function, the thickness filters are capable of projecting discrete 0/1 values to the underlying layerwise or ”physical” density variables which...

Braile vena cava filter and greenfield filter in terms of centralization.

Science.gov (United States)

de Godoy, José Maria Pereira; Menezes da Silva, Adinaldo A; Reis, Luis Fernando; Miquelin, Daniel; Torati, José Luis Simon

2013-01-01

The aim of this study was to evaluate complications experienced during implantation of the Braile Vena Cava filter (VCF) and the efficacy of the centralization mechanism of the filter. This retrospective cohort study evaluated all Braile Biomédica VCFs implanted from 2004 to 2009 in Hospital de Base Medicine School in São José do Rio Preto, Brazil. Of particular concern was the filter's symmetry during implantation and complications experienced during the procedure. All the angiographic examinations performed during the implantation of the filters were analyzed in respect to the following parameters: migration of the filter, non-opening or difficulties in the implantation and centralization of the filter. A total of 112 Braile CVFs were implanted and there were no reports of filter opening difficulties or in respect to migration. Asymmetry was observed in 1/112 (0.9%) cases. A statistically significant difference was seen on comparing historical data on decentralization of the Greenfield filter with the data of this study. The Braile Biomédico filter is an evolution of the Greenfield filter providing improved embolus capture and better implantation symmetry.

Quartz substrate infrared photonic crystal

Science.gov (United States)

Ghadiri, Khosrow; Rejeb, Jalel; Vitchev, Vladimir N.

2003-01-01

This paper presents the fabrication of a planar photonic crystal (p2c) made of a square array of dielectric rods embedded in air, operating in the infrared spectrum. A quartz substrate is employed instead of the commonly used silicon or column III-V substrate. Our square structure has a normalized cylinder radius-to-pitch ratio of r/a = 0.248 and dielectric material contrast ɛr of 4.5. We choose a Z-cut synthetic quartz for its cut (geometry), and etching properties. Then a particular Z-axis etching process is employed in order to ensure the sharp-edged verticality of the rods and fast etching speed. We also present the computer simulations that allowed the establishment of the photonic band gaps (PBG) of our photonic crystal, as well as the actual measurements. An experimental measurement have been carried out and compared with different simulations. It was found that experimental results are in good agreement with different simulation results. Finally, a frequency selective device for optical communication based on the introduction of impurity sites in the photonic crystal is presented. With our proposed structure Optical System on a Chip (OsoC) with micro-cavity based active devices such as lasers, diodes, modulators, couplers, frequency selective emitters, add-drop filters, detectors, mux/demuxes and polarizers connected by passive waveguide links can be realized.

Deep Kalman Filter: Simultaneous Multi-Sensor Integration and Modelling; A GNSS/IMU Case Study

Directory of Open Access Journals (Sweden)

Siavash Hosseinyalamdary

2018-04-01

Full Text Available Bayes filters, such as the Kalman and particle filters, have been used in sensor fusion to integrate two sources of information and obtain the best estimate of unknowns. The efficient integration of multiple sensors requires deep knowledge of their error sources. Some sensors, such as Inertial Measurement Unit (IMU, have complicated error sources. Therefore, IMU error modelling and the efficient integration of IMU and Global Navigation Satellite System (GNSS observations has remained a challenge. In this paper, we developed deep Kalman filter to model and remove IMU errors and, consequently, improve the accuracy of IMU positioning. To achieve this, we added a modelling step to the prediction and update steps of the Kalman filter, so that the IMU error model is learned during integration. The results showed our deep Kalman filter outperformed the conventional Kalman filter and reached a higher level of accuracy.

Matched-filtering generalized phase contrast using LCoS pico-projectors for beam-forming

OpenAIRE

Bañas, Andrew Rafael; Palima, Darwin; Glückstad, Jesper

2012-01-01

We report on a new beam-forming system for generating high intensity programmable optical spikes using so-called matched-filtering Generalized Phase Contrast (mGPC) applying two consumer handheld pico-projectors. Such a system presents a low-cost alternative for optical trapping and manipulation, optical lattices and other beam-shaping applications usually implemented with high-end spatial light modulators. Portable pico-projectors based on liquid crystal on silicon (LCoS) devices are used as...

Crystallization and X-ray diffraction analysis of dihydropyrimidinase from Saccharomyces kluyveri

International Nuclear Information System (INIS)

Dobritzsch, Doreen; Andersen, Birgit; Piškur, Jure

2005-01-01

Dihydropyrimidinase from the yeast S. kluyveri was crystallized by vapour diffusion. The crystals belong to space group P2 1 (unit-cell parameters a = 91.0, b = 73.0, c = 161.4 Å, β = 91.4°) and diffracted to 2.6 Å resolution. Dihydropyrimidinase (EC 3.5.2.2) catalyzes the second step in the reductive pathway of pyrimidine degradation, the hydrolysis of 5,6-dihydrouracil and 5,6-dihydrothymine to the corresponding N-carbamylated β-amino acids. Crystals of the recombinant enzyme from the yeast Saccharomyces kluyveri diffracting to 2.6 Å at a synchrotron-radiation source have been obtained by the hanging-drop vapour-diffusion method. They belong to space group P2 1 (unit-cell parameters a = 91.0, b = 73.0, c = 161.4 Å, β = 91.4°), with one homotetramer per asymmetric unit

Production, crystallization and preliminary X-ray diffraction analysis of the allergen Can f 2 from Canis familiaris

International Nuclear Information System (INIS)

Madhurantakam, Chaithanya; Nilsson, Ola B.; Jönsson, Klas; Grönlund, Hans; Achour, Adnane

2009-01-01

The recombinant form of the allergen Can f 2 from C. familiaris was produced, isolated and crystallized in two different forms. Preliminary X-ray diffraction analyses are reported for the two crystal forms of Can f 2. The allergen Can f 2 from dog (Canis familiaris) present in saliva, dander and fur is an important cause of allergic sensitization worldwide. Here, the production, isolation, crystallization and preliminary X-ray diffraction analysis of two crystal forms of recombinant Can f 2 are reported. The first crystal form belonged to space group C222, with unit-cell parameters a = 68.7, b = 77.3, c = 65.1 Å, and diffracted to 1.55 Å resolution, while the second crystal form belonged to space group C2, with unit-cell parameters a = 75.7, b = 48.3, c = 68.7 Å, β = 126.5°, and diffracted to 2.1 Å resolution. Preliminary data analysis indicated the presence of a single molecule in the asymmetric unit for both crystal forms

Purification, crystallization and preliminary X-ray diffraction studies of parakeet (Psittacula krameri) haemoglobin

International Nuclear Information System (INIS)

Jaimohan, S. M.; Naresh, M. D.; Arumugam, V.; Mandal, A. B.

2009-01-01

Parakeet (Psittacula krameri) haemoglobin has been purified and crystallized under low salt buffered conditions. Preliminary analysis of the crystal that belonged to monoclinic system (C2) is reported. Birds often show efficient oxygen management in order to meet the special demands of their metabolism. However, the structural studies of avian haemoglobins (Hbs) are inadequate for complete understanding of the mechanism involved. Towards this end, purification, crystallization and preliminary X-ray diffraction studies have been carried out for parakeet Hb. Parakeet Hb was crystallized as the met form in low-salt buffered conditions after extracting haemoglobin from crude blood by microcentrifugation and purifying the sample by column chromatography. Good-quality crystals were grown from 10% PEG 3350 and a crystal diffracted to about 2.8 Å resolution. Preliminary diffraction data showed that the Hb crystal belonged to the monoclinic system (space group C2), with unit-cell parameters a = 110.68, b = 64.27, c = 56.40 Å, β = 109.35°. Matthews volume analysis indicated that the crystals contained a half-tetramer in the asymmetric unit

Structural Color Patterns by Electrohydrodynamic Jet Printed Photonic Crystals.

Science.gov (United States)

Ding, Haibo; Zhu, Cun; Tian, Lei; Liu, Cihui; Fu, Guangbin; Shang, Luoran; Gu, Zhongze

2017-04-05

In this work, we demonstrate the fabrication of photonic crystal patterns with controllable morphologies and structural colors utilizing electrohydrodynamic jet (E-jet) printing with colloidal crystal inks. The final shape of photonic crystal units is controlled by the applied voltage signal and wettability of the substrate. Optical properties of the structural color patterns are tuned by the self-assembly of the silica nanoparticle building blocks. Using this direct printing technique, it is feasible to print customized functional patterns composed of photonic crystal dots or photonic crystal lines according to relevant printing mode and predesigned tracks. This is the first report for E-jet printing with colloidal crystal inks. Our results exhibit promising applications in displays, biosensors, and other functional devices.

Creation of an iOS and Android Mobile Application for Inferior Vena Cava (IVC) Filters: A Powerful Tool to Optimize Care of Patients with IVC Filters.

Science.gov (United States)

Deso, Steven E; Idakoji, Ibrahim A; Muelly, Michael C; Kuo, William T

2016-06-01

Owing to a myriad of inferior vena cava (IVC) filter types and their potential complications, rapid and correct identification may be challenging when encountered on routine imaging. The authors aimed to develop an interactive mobile application that allows recognition of all IVC filters and related complications, to optimize the care of patients with indwelling IVC filters. The FDA Premarket Notification Database was queried from 1980 to 2014 to identify all IVC filter types in the United States. An electronic search was then performed on MEDLINE and the FDA MAUDE database to identify all reported complications associated with each device. High-resolution photos were taken of each filter type and corresponding computed tomographic and fluoroscopic images were obtained from an institutional review board-approved IVC filter registry. A wireframe and storyboard were created, and software was developed using HTML5/CSS compliant code. The software was deployed using PhoneGap (Adobe, San Jose, CA), and the prototype was tested and refined. Twenty-three IVC filter types were identified for inclusion. Safety data from FDA MAUDE and 72 relevant peer-reviewed studies were acquired, and complication rates for each filter type were highlighted in the application. Digital photos, fluoroscopic images, and CT DICOM files were seamlessly incorporated. All data were succinctly organized electronically, and the software was successfully deployed into Android (Google, Mountain View, CA) and iOS (Apple, Cupertino, CA) platforms. A powerful electronic mobile application was successfully created to allow rapid identification of all IVC filter types and related complications. This application may be used to optimize the care of patients with IVC filters.

Status Report and Research Plan for Cables Harvested from Crystal River Unit 3 Nuclear Generating Plant

Energy Technology Data Exchange (ETDEWEB)

Fifield, Leonard S. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2016-09-20

Harvested cables from operating or decommissioned nuclear power plants present an important opportunity to validate models, understanding material aging behavior, and validate characterization techniques. Crystal River Unit 3 Nuclear Generating Plant is a pressurized water reactor that was licensed to operate from 1976 to 2013. Cable segments were harvested and made available to the Light Water Reactor Sustainability research program through the Electric Power Research Institute. Information on the locations and circuits within the reactor from whence the cable segments came, cable construction, sourcing and installation information, and photographs of the cable locations prior to harvesting were provided. The cable variations provided represent six of the ten most common cable insulations in the nuclear industry and experienced service usage for periods from 15 to 42 years. Subsequently, these cables constitute a valuable asset for research to understand aging behavior and measurement of nuclear cables. Received cables harvested from Crystal River Unit 3 Nuclear Generating Plant consist of low voltage, insulated conductor surrounded by jackets in lengths from 24 to 100 feet each. Cable materials will primarily be used to investigate aging under simultaneous thermal and gamma radiation exposure. Each cable insulation and jacket material will be characterized in its as-received condition, including determination of the temperatures associated with endothermic transitions in the material using differential scanning calorimetry and dynamic mechanical analysis. Temperatures for additional thermal exposure aging will be selected following the thermal analysis to avoid transitions in accelerated laboratory aging that do not occur in field conditions. Aging temperatures above thermal transitions may also be targeted to investigate the potential for artifacts in lifetime prediction from rapid accelerated aging. Total gamma doses and dose rates targeted for each material

TESTING OF THE SECOND GENERATION SPINTEK ROTARY FILTER -11357