Sample records for absorbed assessment quantificacao

  1. Quantification of micronuclei in blood lymphocytes of patients exposed to gamma radiation for dose absorbed assessment; Quantificacao de micronucleos em linfocitos de pacientes expostas a radiacao gama para a avaliacao da dose absorvida

    Barbosa, Isvania Maria Serafim da Silva


    Dose assessment in an important step to evaluate biological effects as a result of individual exposure to ionizing radiation. The use of cytogenetic dosimetry based on the quantification of micronuclei in lymphocytes is very important to complement physical dosimetry, since the measurement of absorbed dose cannot be always performed. In this research, the quantification of micronuclei was carried out in order to evaluate absorbed dose as a result of radiotherapy with {sup 60}Co, using peripheral blood samples from 5 patients with cervical uterine cancer. For this purpose, an aliquot of whole blood from the individual patients was added in culture medium RPMI 1640 supplemented with fetal calf serum and phytohaemagglutinin. The culture was incubated for 44 hours. Henceforth, cytochalasin B was added to block the dividing lymphocytes in cytokinesis. The culture was returned to the incubator for further of 28 hours. Thus, cells were harvested, processed and analyzed. Values obtained considering micronuclei frequency after pelvis irradiation with absorption of 0,08 Gy and 1,8 Gy were, respectively, 0,0021 and 0,052. These results are in agreement with some recent researches that provided some standard values related to micronuclei frequency induced by gamma radiation exposure in different exposed areas for the human body. The results presented in this report emphasizes biological dosimetry as an important tool for dose assessment of either total or partial-body exposure to ionizing radiation, mainly in retrospective dose investigation. (author)

  2. Assessment criteria for assessing energy-absorbing front underrun protection on trucks

    Schram, R.; Leneman, F.J.W.; Zweep, C. van der; Wismans, J.S.H.M.; Witteman, W.J.


    The objective of this article is to investigate the possibilities to assess (energy-absorbing) front underrun protection (FUP) devices with respect to injuries of the car occupant without using a car and dummy in the test procedure. A large number of different crash configurations are simulated to

  3. Blood compounds irradiation process: assessment of absorbed dose using Fricke and Thermoluminescent dosimetric systems

    Soares, Gabriela de Amorim; Squair, Peterson Lima; Pinto, Fausto Carvalho; Belo, Luiz Claudio Meira; Grossi, Pablo Andrade [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN-CNEN/MG), Belo Horizonte, MG (Brazil)], e-mail:, e-mail:, e-mail:, e-mail:, e-mail:


    The assessment of gamma absorbed doses in irradiation facilities allows the quality assurance and control of the irradiation process. The liability of dose measurements is assign to the metrological procedures adopted including the uncertainty evaluation. Fricke and TLD 800 dosimetric systems were used to measure absorbed dose in the blood compounds using the methodology presented in this paper. The measured absorbed doses were used for evaluating the effectiveness of the irradiation procedure and the gamma dose absorption inside the irradiation room of a gamma irradiation facility. The radiation eliminates the functional and proliferative capacities of donor T-lymphocytes, preventing Transfusion associated graft-versus-host disease (TA-GVHD), a possible complication of blood transfusions. The results show the applicability of such dosimetric systems in quality assurance programs, assessment of absorbed doses in blood compounds and dose uniformity assign to the blood compounds irradiation process by dose measurements in a range between 25 Gy and 100 Gy. (author)

  4. [Characterization and soil environmental safety assessment of super absorbent polymers in agricultural application].

    Li, Xi; Liu, Yu-Rong; Zheng, Yuan-Ming; He, Ji-Zheng


    Super absorbent polymers (SAPs) are compounds that can absorb a lot of water which can be several folds of their original size and weight. They can increase soil water content and aggregates, promote fertilizer utilization efficiency, and stimulate crop growth. Therefore, SAPs have been widely regarded as a potential agent for water-saving agriculture. In this paper, we reviewed the advances of SAPs in materials, properties and applications in agriculture and pointed out that the absence of influences of SAPs on soil microbial ecology was the main issue in current studies. In regard to the adverse effects on soil environment caused by misuse of SAPs, we should address the systematic safety assessment of SAPs application in the soil, especially the effects on the soil microorganisms, which should be an important part of chemicals risk assessment in the soil application.

  5. Application of Charpy Impact Absorbed Energy to the Safety Assessment Based on SINTAP


    The European Structural Integrity Assessment Procedure(SINTAP) was applied to the assessment of welded joints of the APl 5L X65 pipeline steel with an assumed embedded flaw and surface flaw at the weld toe. At default level( level 0), the assessment point was established by estimating fracture toughness value KIc conservatively from Charpy energy test data. At the same time, the analysis level 1 (basic level)was applied based on the fracture toughness CTOD. Then the two assessment levels were compared. The assessment results show that all assessment points are located within the failure lines of analysis levels 0 and 1. So the welded joint of the pipeline is safe. It can be concluded that the assessment based on Charpy absorbed energy is practicable when other fracture toughness data are not available, or cannot be easily obtained. The results are conservative.

  6. Methodology for assessing the performance of urine absorbing aids in controlling malodour release.

    Sironi, S; Capelli, L; Dentoni, L; Del Rosso, R


    The aim of this study was to investigate the possibility of comparing the performance of different absorbent aids in terms of odour control by discussing a suitable methodology for product evaluation. To overcome the problems of low test reproducibility owing to biological urine variability, the first step of the work consisted of the identification and the production of artificial urine having a constant and stable composition over time, moreover preventing sensorial assessors from any risk of biological contamination. Sensorial measurements were performed to optimize the similarity between artificial and biological urine, especially as far as the composition of the volatile component and therefore of the odour properties are concerned. The assessment of absorbent articles performance to control urine malodour includes both the concentration and the hedonic tone of the odour released by the article itself loaded with synthetic urine. Analyses were run on different products, which can be grouped into two different classes: absorbing aids with or without odour control technology (OCT) respectively. Results show that, despite of the presence or absence of OCT on absorbing products, their odour concentrations are almost identical, being comprised between 10 000 and 12 000 ouE m(-3) . For this reason, it is evident that odour concentration is not suitable as the sole parameter for comparison of different absorbing products. Instead, the hedonic odour tone (odour pleasantness/unpleasantness) relevant to the different product typologies (that is products with and without OCT) should be used as an additional discriminating factor for this kind of comparative tests.

  7. Safety assessment of sanitary pads with a polymeric foam absorbent core.

    Woeller, Kara E; Hochwalt, Anne E


    Sanitary pads for menstrual hygiene have a layered design consisting of a fluid permeable surface (topsheet), an absorbent core, and an impermeable backing with adhesive. Most sanitary pads employ cellulose-based cores. This describes the safety evaluation of a menstrual pad with an emollient-treated topsheet and a novel polymeric foam core. A quantitative risk assessment was performed, which included: (1) toxicological evaluation of the raw material components; (2) quantitative exposure assessments of pad constituents, accounting for the fluid handling properties of the product and pertinent conditions of use; and (3) risk characterization for exposure to raw materials (e.g., potential for skin irritation, contact sensitization, or systemic effects, if relevant) and to the physical article itself (potential effects on skin friction, etc.). No significant risk of adverse effects was found. Five years of post-market surveillance substantiates that the product is well-tolerated (1 health complaint reported per 2 million products shipped to market) and surpasses women's expectations for menstrual protection and overall comfort and dryness. This report illustrates how the classical risk assessment paradigm, informed by the impact of product design, functionality and pertinent use conditions, allowed the systematic safety evaluation of a personal hygiene product with a novel, non-cellulosic absorbent foam core technology.

  8. Assessment of the absorbed dose to organs from bone mineral density scan by using TLDS and the Monte Carlo method

    Karimian Alireza


    Full Text Available Nowadays, dual energy X-ray absorptiometry is used in bone mineral density systems to assess the amount of osteoporosis. The purpose of this research is to evaluate patient organ doses from dual X-ray absorptiometry by thermoluminescence dosimeters chips and Monte Carlo method. To achieve this goal, in the first step, the surface dose of the cervix, kidney, abdomen region, and thyroid were measured by using TLD-GR 200 at various organ locations. Then, to evaluate the absorbed dose by simulation, the BMD system, patient's body, X-ray source and radiosensitive tissues were simulated by the Monte Carlo method. The results showed, for the spine (left femur bone mineral density scan by using thermoluminescence dosimeters, the absorbed doses of the cervix and kidney were 4.5 (5.64 and 162.17 (3.99(mGy, respectively. For spine (left femur bone mineral density scan in simulation, the absorbed doses of the cervix and kidney were 4.19 (5.88 and 175 (3.68(mGy, respectively. The data obtained showed that the absorbed dose of the kidney in the spine scan is noticeable. Furthermore, because of the small relative difference between the simulation and experimental results, the radiation absorbed dose may be assessed by simulation and software, especially for internal organs, and at different depths of otherwise inaccessible organs which is not possible in experiments.

  9. Nectarine Fruit Ripening and Quality Assessed Using the Index of Absorbance Difference (IAD

    E. Bonora


    Full Text Available Consistency of fruit quality is extremely important in horticulture. Fruit growth and quality in nectarine are affected by fruit position in the canopy, related to the tree shape. The “open shaped” training systems, such as Tatura Trellis, improve fruit growth and quality. The Index of Absorbance Difference (IAD is a new marker that characterizes climacteric fruit during ripening. A study on fruit ripening was performed by using the IAD on nectarine to monitor fruit maturity stages of two cultivars trained as Tatura Trellis in Victoria, Australia. Fruit of cv “Summer Flare 34” (“SF34” grown in different positions on the tree showed high ripening homogeneity. Fruit harvested at a similar ripening stage showed fruit firmness and soluble solid content homogeneity. Fruits from hand-thinned variety “Summer Flare 26” (“SF26” were larger in size, had advanced ripening, and showed greater homogeneity. For “SF26”, a weak correlation between IAD and SSC was observed. The experiment showed that the Tatura Trellis training system is characterized by high homogeneity of nectarine fruit when coupled with a proper management of fruit density. It also confirmed that the IAD could be used as new nondestructive maturity index for nectarine fruit quality assessment in the field.

  10. Absorbed dose assessment in particle-beam irradiated metal-oxide and metal-nonmetal memristors

    Knežević Ivan D.


    Full Text Available Absorbed dose was estimated after Monte Carlo simulation of proton and ion beam irradiation on metal-oxide and metal-nonmetal memristors. A memristive device comprises two electrodes, each of a nanoscale width, and a double-layer active region disposed between and in electrical contact with electrodes. Following materials were considered for the active region: titanium dioxide, zirconium dioxide, hafnium dioxide, strontium titanium trioxide and galium nitride. Obtained results show that significant amount of oxygen ion - oxygen and nonmetal ion - nonmetal vacancy pairs is to be generated. The loss of such vacancies from the device is believed to deteriorate the device performance over time. Estimated absorbed dose values in the memristor for different constituting materials are of the same order of magnitude because of the close values of treshold displacement energies for the investigated materials.

  11. Lung involvement quantification in chest radiographs; Quantificacao de comprometimento pulmonar em radiografias de torax

    Giacomini, Guilherme; Alvarez, Matheus; Oliveira, Marcela de; Miranda, Jose Ricardo A. [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Botucatu, SP (Brazil). Instituto de Biociencias. Departamento de Fisica e Biofisica; Pina, Diana R.; Pereira, Paulo C.M.; Ribeiro, Sergio M., E-mail: [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Botucatu, SP (Brazil). Faculdade de Medicina. Departamento de Doencas Tropicais e Diagnostico por Imagem


    Tuberculosis (TB) caused by Mycobacterium tuberculosis, is an infectious disease which remains a global health problem. The chest radiography is the commonly method employed to assess the TB's evolution. The methods for quantification of abnormalities of chest are usually performed on CT scans (CT). This quantification is important to assess the TB evolution and treatment and comparing different treatments. However, precise quantification is not feasible for the amount of CT scans required. The purpose of this work is to develop a methodology for quantification of lung damage caused by TB through chest radiographs. It was developed an algorithm for computational processing of exams in Matlab, which creates a lungs' 3D representation, with compromised dilated regions inside. The quantification of lung lesions was also made for the same patients through CT scans. The measurements from the two methods were compared and resulting in strong correlation. Applying statistical Bland and Altman, all samples were within the limits of agreement, with a confidence interval of 95%. The results showed an average variation of around 13% between the two quantification methods. The results suggest the effectiveness and applicability of the method developed, providing better risk-benefit to the patient and cost-benefit ratio for the institution. (author)

  12. Remote sensing assessment of absorbing aerosol over Peninsular Malaysia from OMI onboard Aura satellite

    Tan, K. C.; Lim, H. S.; Mat Jafri, M. Z.


    The observation of aerosol index derived from the Ozone Monitoring Instrument (OMI) on board the Dutch-Finnish Aura satellite with spatial resolution 1° x 1° have been analyzed over Peninsular Malaysia for 2013-2015, from June to September, respectively. The results show significant spatial and temporal variabilities in aerosol index with higher values during June 2013 and September 2015. On the other hand, the aerosol index does not show significant differences between the Peninsular Malaysia for the remaining study duration. The high positive aerosol index values over Southern Peninsular Malaysia clearly reveal the ultraviolet absorbing nature of smoke particles affecting the area during Indonesia forest fire, associated with the Southwest monsoon season. The spatial distribution of aerosol index has been analyzed using monthly OMI/Aura data obtained from the NASA-operated Giovanni. The result shows that the satellite measurements can measure and observe the increase of the aerosol index over different regions.

  13. MICE -- Absorber and focus coil safety working group design document: Preliminary design and assessments

    Barr, Giles; Baynham, Elwyn; Black, Edgar; Bradshaw, Tom; Cummings, Mary Anne; Green, Michael A.; Ishimoto, Shigeru; Ivanyushenkov, Yury; Lau, Wing; Zisman, Michael


    A Neutrino Factory based on a muon storage ring is the ultimate tool for studies of neutrino oscillations, including possibly the discovery of leptonic CP violation. it is also the first step toward a muon collider. To develop a stored-muon-beam facility to serve as a Neutrino Factory, it is necessary to ''cool'' a muon beam (decrease its phase-space volume). The short lifetime of the muon, 2.2 {micro}s at rest, eliminates all currently demonstrated cooling techniques and requires that a new, heretofore untried, technique--ionization cooling--be employed. Although ionization cooling of muons has never been demonstrated in practice, it has been shown by end-to-end simulation and design studies to be an important factor both for the performance and for the cost of a Neutrino Factory. This motivates an international program of R and D, including an experimental demonstration at Rutherford Appleton Laboratory (RAL). The aims of the international Muon Ionization Cooling Experiment are: (1) to show that it is possible to design, engineer and build a section of cooling channel capable of giving the desired performance for a Neutrino Factory; and (2) to place it in a muon beam and measure its performance in various modes of operation and beam conditions, thereby investigating the limits and practicality of cooling. The MICE collaboration has designed an experiment in which a section of an ionization cooling channel is exposed to a muon beam. This cooling channel assembles liquid-hydrogen absorbers providing energy loss and high-gradient radio frequency (RF) cavities to re-accelerate the particles, all tightly contained in a magnetic channel. It reduces the beam transverse emittance by > 10% for muon momenta between 140 and 240 MeV/c. The layout of the experiment is shown. They utilize one complete magnetic cell of the cooling channel, comprising three absorber-focus-coil (AFC) modules and two RF-coupling-coil (RFCC) modules. Spectrometers placed before

  14. Assessment of capabilities of multiangle imaging photo-polarimetry for atmospheric correction in presence of absorbing aerosols

    Kalashnikova, O. V.; Garay, M. J.; Xu, F.; Seidel, F. C.; Diner, D. J.


    Satellite remote sensing of ocean color is a critical tool for assessing the productivity of marine ecosystems and monitoring changes resulting from climatic or environmental influences. Yet water-leaving radiance comprises less than 10% of the signal measured from space, making correction for absorption and scattering by the intervening atmosphere imperative. Traditional ocean color retrieval algorithms utilize a standard set of aerosol models and the assumption of negligible water-leaving radiance in the near-infrared. Modern improvements have been developed to handle absorbing aerosols such as urban particulates in coastal areas and transported desert dust over the open ocean, where ocean fertilization can impact biological productivity at the base of the marine food chain. Even so, imperfect knowledge of the absorbing aerosol optical properties or their height distribution results in well-documented sources of error. In the UV, the problem of UV-enhanced absorption and nonsphericity of certain aerosol types are amplified due to the increased Rayleigh and aerosol optical depth, especially at off-nadir view angles. Multi-angle spectro-polarimetric measurements have been advocated as an additional tool to better understand and retrieve the aerosol properties needed for atmospheric correction for ocean color retrievals. The central concern of the work to be described is the assessment of the effects of absorbing aerosol properties on water leaving radiance measurement uncertainty by neglecting UV-enhanced absorption of carbonaceous particles and by not accounting for dust nonsphericity. In addition, we evaluate the polarimetric sensitivity of absorbing aerosol properties in light of measurement uncertainties achievable for the next generation of multi-angle polarimetric imaging instruments, and demonstrate advantages and disadvantages of wavelength selection in the UV/VNIR range. The phase matrices for the spherical smoke particles were calculated using a standard

  15. Sound Absorbers

    Fuchs, H. V.; Möser, M.

    Sound absorption indicates the transformation of sound energy into heat. It is, for instance, employed to design the acoustics in rooms. The noise emitted by machinery and plants shall be reduced before arriving at a workplace; auditoria such as lecture rooms or concert halls require a certain reverberation time. Such design goals are realised by installing absorbing components at the walls with well-defined absorption characteristics, which are adjusted for corresponding demands. Sound absorbers also play an important role in acoustic capsules, ducts and screens to avoid sound immission from noise intensive environments into the neighbourhood.

  16. Assessment of effective absorbed dose of (111)In-DTPA-Buserelin in human on the basis of biodistribution rat data.

    Lahooti, Afsaneh; Shanehsazzadeh, Saeed; Jalilian, Amir Reza; Tavakoli, Mohammad Bagher


    In this study, the effective absorbed dose to human organs was estimated, following intra vascular administration of (111)In-DTPA-Buserelin using biodistribution data from rats. Rats were sacrificed at exact time intervals of 0.25, 0.5, 1, 2, 4 and 24 h post injections. The Medical Internal Radiation Dose formulation was applied to extrapolate from rats to humans and to project the absorbed radiation dose for various human organs. From rat data, it was estimated that a 185-MBq injection of (111)In-DTPA-Buserelin into the human might result in an estimated absorbed dose of 24.27 mGy to the total body and the highest effective absorbed dose was in kidneys, 28.39 mSv. The promising results of this study emphasises the importance of absorbed doses in humans estimated from data on rats.

  17. Assessing the Progress and the Underlying Nature of the Flows of Doctoral and Master Degree Candidates Using Absorbing Markov Chains

    Nicholls, Miles G.


    In this paper, absorbing markov chains are used to analyse the flows of higher degree by research candidates (doctoral and master) within an Australian faculty of business. The candidates are analysed according to whether they are full time or part time. The need for such analysis stemmed from what appeared to be a rather poor completion rate (as…

  18. Absorbing and transferring risk: assessing the impact of a statewide high-risk-pregnancy telemedical program on VLBW maternal transports

    Norton Jonathan D


    Full Text Available Abstract Background Prior research has shown that resources have an impact on birth outcomes. In this paper we ask how combinations of telemedical and hospital-level resources impact transports of mothers expecting very low birth weight (VLBW babies in Arkansas. Methods Using de-identified birth certificate data from the Arkansas Department of Health, data were gathered on transports of women carrying VLBW babies for two six-month periods: a period just before the start of ANGELS (12/02-05/03, a telemedical outreach program for high-risk pregnancies, and a period after the program had been running for six months (12/03-05/04. For each maternal transport, the following information was recorded: maternal race-ethnicity, maternal age, and the birth weight of the infant. Logistic regression was used to assess the relationship between the predictors (telemedicine, hospital level, maternal characteristics and the probability of a transport. Results Having a telemedical site available increases the probability of a mother carrying a VLBW baby being transported to a level III facility either before or during birth. Having at least a level II nursery also increases the chance of a maternal transport. Where both level II nurseries and telemedical access are available, the odds of VLBW maternal transports are only modestly increased in comparison to the case where neither is present. At the individual level, Hispanic mothers were less likely to be transported than other mothers, and teenaged mothers were more likely to be transported than those 18 and over. A mother's being Black or being over 35 did not have an impact on the odds of being transported to a level III facility. Conclusion Combinations of resources have an impact on physician decisions regarding VLBW transports and are interpretable in terms of the capacity to diagnose and absorb risk. We suggest a collegial review of transport patterns and birth outcomes from areas with different levels of

  19. Development of methodology for assessment of absorbed dose and stopping power for low energy conversion electrons; Desenvolvimento de uma metodologia para estimativa da dose absorvida e do poder de freamento para eletrons de conversao de baixa energia

    Almeida, Ivan Pedro Salati de


    The evaluation of absorbed dose in the case of external and internalcontamination due to radionuclides is sometimes hard, because of the difficulties in the assessment of the absorbed dose caused by electrons with energy less than 100 KeV in mucous membrane. In this work, a methodology for assessment of absorbed dose and stopping power in VYNS (co-polymer of polivinyl chloride - acetate) absorbers, for the 62.5 KeV and 84-88 KeV energy {sup 109} Cd conversion electrons, working with a 4 {pi} proportional pressurized detector, is presented. In order to assure the reproducibility of measurement conditions, one of the detector halves has been used to obtain a spectrum of a thin {sup 109} Cd source, without absorber. The other half of the detector was used in concomitance to obtain spectra with different thicknesses if absorber. The absorbed energy was obtained subtracting each spectrum with absorber from the spectrum without absorber, which were stored in a microcomputer connected to signal processing systems by ACE type interface. The VYNS weight and thickness were evaluated using common radionuclide metrology procedures. As VYNS has characteristics similar to a tissue equivalent material, the results obtained are consistent with dosimetric concepts and have a good agreement with those of the literature. (author)

  20. Development of modern approach to absorbed dose assessment in radionuclide therapy, based on Monte Carlo method simulation of patient scintigraphy

    Lysak, Y. V.; Klimanov, V. A.; Narkevich, B. Ya


    One of the most difficult problems of modern radionuclide therapy (RNT) is control of the absorbed dose in pathological volume. This research presents new approach based on estimation of radiopharmaceutical (RP) accumulated activity value in tumor volume, based on planar scintigraphic images of the patient and calculated radiation transport using Monte Carlo method, including absorption and scattering in biological tissues of the patient, and elements of gamma camera itself. In our research, to obtain the data, we performed modeling scintigraphy of the vial with administered to the patient activity of RP in gamma camera, the vial was placed at the certain distance from the collimator, and the similar study was performed in identical geometry, with the same values of activity of radiopharmaceuticals in the pathological target in the body of the patient. For correct calculation results, adapted Fisher-Snyder human phantom was simulated in MCNP program. In the context of our technique, calculations were performed for different sizes of pathological targets and various tumors deeps inside patient’s body, using radiopharmaceuticals based on a mixed β-γ-radiating (131I, 177Lu), and clear β- emitting (89Sr, 90Y) therapeutic radionuclides. Presented method can be used for adequate implementing in clinical practice estimation of absorbed doses in the regions of interest on the basis of planar scintigraphy of the patient with sufficient accuracy.

  1. On the suitability of ultrathin detectors for absorbed dose assessment in the presence of high-density heterogeneities

    Bueno, M., E-mail:; Duch, M. A. [Institut de Tècniques Energètiques, Universitat Politècnica de Catalunya, 08028 Barcelona (Spain); Carrasco, P.; Jornet, N. [Servei de Radiofísica i Radioprotecció, Hospital de la Santa Creu i de Sant Pau, 08025 Barcelona (Spain); Muñoz-Montplet, C. [Servei de Física Mèdica i Protecció Radiològica, Institut Català d’Oncologia—Girona, 17007 Girona (Spain)


    Purpose: The aim of this study was to evaluate the suitability of several detectors for the determination of absorbed dose in bone. Methods: Three types of ultrathin LiF-based thermoluminescent dosimeters (TLDs)—two LiF:Mg,Cu,P-based (MCP-Ns and TLD-2000F) and a{sup 7}Li-enriched LiF:Mg,Ti-based (MTS-7s)—as well as EBT2 Gafchromic films were used to measure percentage depth-dose distributions (PDDs) in a water-equivalent phantom with a bone-equivalent heterogeneity for 6 and 18 MV and a set of field sizes ranging from 5×5 cm{sup 2} to 20×20 cm{sup 2}. MCP-Ns, TLD-2000F, MTS-7s, and EBT2 have active layers of 50, 20, 50, and 30 μm, respectively. Monte Carlo (MC) dose calculations (PENELOPE code) were used as the reference and helped to understand the experimental results and to evaluate the potential perturbation of the fluence in bone caused by the presence of the detectors. The energy dependence and linearity of the TLDs’ response was evaluated. Results: TLDs exhibited flat energy responses (within 2.5%) and linearity with dose (within 1.1%) within the range of interest for the selected beams. The results revealed that all considered detectors perturb the electron fluence with respect to the energy inside the bone-equivalent material. MCP-Ns and MTS-7s underestimated the absorbed dose in bone by 4%–5%. EBT2 exhibited comparable accuracy to MTS-7s and MCP-Ns. TLD-2000F was able to determine the dose within 2% accuracy. No dependence on the beam energy or field size was observed. The MC calculations showed that a50 μm thick detector can provide reliable dose estimations in bone regardless of whether it is made of LiF, water or EBT’s active layer material. Conclusions: TLD-2000F was found to be suitable for providing reliable absorbed dose measurements in the presence of bone for high-energy x-ray beams.

  2. Development of computational algorithms for quantification of pulmonary structures; Desenvolvimento de algoritmos computacionais para quantificacao de estruturas pulmonares

    Oliveira, Marcela de; Alvarez, Matheus; Alves, Allan F.F.; Miranda, Jose R.A., E-mail: [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Botucatu, SP (Brazil). Instituto de Biociencias. Departamento de Fisica e Biofisica; Pina, Diana R. [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Botucatu, SP (Brazil). Hospital das Clinicas. Departamento de Doencas Tropicais e Diagnostico por Imagem


    The high-resolution computed tomography has become the imaging diagnostic exam most commonly used for the evaluation of the squeals of Paracoccidioidomycosis. The subjective evaluations the radiological abnormalities found on HRCT images do not provide an accurate quantification. The computer-aided diagnosis systems produce a more objective assessment of the abnormal patterns found in HRCT images. Thus, this research proposes the development of algorithms in MATLAB® computing environment can quantify semi-automatically pathologies such as pulmonary fibrosis and emphysema. The algorithm consists in selecting a region of interest (ROI), and by the use of masks, filter densities and morphological operators, to obtain a quantification of the injured area to the area of a healthy lung. The proposed method was tested on ten HRCT scans of patients with confirmed PCM. The results of semi-automatic measurements were compared with subjective evaluations performed by a specialist in radiology, falling to a coincidence of 80% for emphysema and 58% for fibrosis. (author)

  3. Combination of UV absorbance and electron donating capacity to assess degradation of micropollutants and formation of bromate during ozonation of wastewater effluents.

    Chon, Kangmin; Salhi, Elisabeth; von Gunten, Urs


    In this study, the changes in UV absorbance at 254 nm (UVA254) and electron donating capacity (EDC) were investigated as surrogate indicators for assessing removal of micropollutants and bromate formation during ozonation of wastewater effluents. To measure the EDC, a novel method based on size exclusion chromatography followed by a post-column reaction was developed and calibrated against an existing electrochemical method. Low specific ozone doses led to a more efficient abatement of EDC than of UVA254. This was attributed to the abatement of phenolic moieties in the dissolved organic matter (DOM), which lose their EDC upon oxidation, but are partially transformed into quinones, which still absorb in the measured UV range. For higher specific ozone doses, the relative EDC abatement was lower than the relative UVA abatement, which can be explained by the oxidation of UV absorbing moieties (e.g. non-activated aromatic compounds), which contribute less to EDC. The abatement of the selected micropollutants (i.e., 17α-ethinylestradiol (EE2), carbamazepine (CBZ), atenolol (ATE), bezafibrate (BZF), ibuprofen (IBU), and p-chlorobenzoic acid (pCBA)) varied significantly depending on their reactivity with ozone in the examined specific ozone dose range of 0-1.45 mgO3/mgDOC. The decrease of EE2 and CBZ with high ozone reactivity was linearly proportional to the reduction of the relative residuals of UVA254 and EDC. The abatement of ATE, BZF, IBU, and pCBA with intermediate to low ozone reactivities was not significant in a first phase (UVA254/UVA254,0 = 1.00-0.70; EDC/EDC0 = 1.00-0.56) while their abatement was more efficient than the degradation of the relative residual UVA254 and much more noticeable than the degradation of the relative residual EDC in a second phase (UVA254/UVA254,0 = 0.70-0.25; EDC/EDC0 = 0.56-0.25) because the partially destroyed UV absorbing and electron donating DOM moieties become recalcitrant to ozone attack. Bromate formation was

  4. An introduction to absorbent dressings.

    Jones, Menna Lloyd


    Exudate bathes the wound bed with a serous fluid that contains essential components that promote wound healing. However, excess exudate is often seen as a challenge for clinicians. Absorbent dressings are often used to aid in the management of exudate, with the aim of providing a moist but unmacerated environment. With so many different types of absorbent dressings available today-alongside making a holistic assessment-it is essential that clinicians also have the knowledge and skill to select the most appropriate absorbent dressing for a given patient.

  5. [Environmental safety assessment on the new super absorbent polymers applied into a soil-Chinese cabbage system].

    Li, Xi; He, Ji-Zheng; Zheng, Yuan-Ming; Zheng, Ming-Lan


    Super absorbent polymers (SAPs), a new water retention material, have a potential for application in water-saving agricultural production. In this study, we investigated the effects of SAPs, synthesized from natural plant extracts, on Chinese cabbage fresh weight, soil water content, soil water stable aggregates, soil microbial biomass (carbon) and soil microbial respiration under three water conditions (excessive, normal and deficient) and two SAPs application strategies (bulk treatment and spraying treatment). The results showed that the SAPs significantly promoted the soil water content, water-stable aggregates (> 0.25 mm) and the soil microbial activities, especially under the water deficient conditions. Meanwhile, SAP application strategy was of great significance to the effects on Chinese cabbage and soil properties. Compared with the control treatment under normal water condition, spraying treatment of Jaguar C (S-JC) could reduce irrigation water amount by about 25% without reducing the crop production. Furthermore, compared with the control treatment under the same water condition with S-JC (deficient), it could increase Chinese cabbage production by 287%. Thus, SAPs is an environmental friendly water-saving technique in agricultural production.

  6. Composite absorbing potentials

    Palao, J P; Sala, P R


    The multiple scattering interferences due to the addition of several contiguous potential units are used to construct composite absorbing potentials that absorb at an arbitrary set of incident momenta or for a broad momentum interval.

  7. The ALICE absorbers

    Maximilien Brice


    Weighing more than 400 tonnes, the ALICE absorbers and the surrounding support structures have been installed and aligned with a precision of 1-2 mm, hardly an easy task but a very important one. The ALICE absorbers are made of three parts: the front absorber, a 35-tonne cone-shaped structure, and two small-angle absorbers, long straight cylinder sections weighing 18 and 40 tonnes. The three pieces lined up have a total length of about 17 m.

  8. Quantitative assessment of selective in-plane shielding of tissues in computed tomography through evaluation of absorbed dose and image quality

    Geleijns, J.; Veldkamp, W.J.H. [Leiden University Medical Center, Radiology Department, ZA Leiden (Netherlands); Salvado Artells, M.; Lopez Tortosa, M. [Universitat Rovira i Virgili, Facultat de Medicina i Ciencies de la Salut, Departament de Ciencies Mediques Basiques, Reus, Tarragona (Spain); Calzado Cantera, A. [Universidad Complutense de Madrid, Departamento de Radiologia, Madrid (Spain)


    This study aimed at assessment of efficacy of selective in-plane shielding in adults by quantitative evaluation of the achieved dose reduction and image quality. Commercially available accessories for in-plane shielding of the eye lens, thyroid and breast, and an anthropomorphic phantom were used for the evaluation of absorbed dose and image quality. Organ dose and total energy imparted were assessed by means of a Monte Carlo technique taking into account tube voltage, tube current, and scanner type. Image quality was quantified as noise in soft tissue. Application of the lens shield reduced dose to the lens by 27% and to the brain by 1%. The thyroid shield reduced thyroid dose by 26%; the breast shield reduced dose to the breasts by 30% and to the lungs by 15%. Total energy imparted (unshielded/shielded) was 88/86 mJ for computed tomography (CT) brain, 64/60 mJ for CT cervical spine, and 289/260 mJ for CT chest scanning. An increase in image noise could be observed in the ranges were bismuth shielding was applied. The observed reduction of organ dose and total energy imparted could be achieved more efficiently by a reduction of tube current. The application of in-plane selective shielding is therefore discouraged. (orig.)

  9. Comparative assessment of “plaque/media” change on three modalities of IVUS immediately after implantation of either everolimus-eluting bioresorbable vascular scaffold or everolimus-eluting metallic stent in Absorb II study

    Y. Zeng (Yaping); R. Cavalcante (Rafael); E. Tenekecioglu (Erhan); P. Suwannasom (Pannipa); Y. Sotomi (Yohei); C. Collet (Carlos); M. Abdelghani (Mohammad); H. Jonker (Hans); Digne, F. (Franck); Horstkotte, D. (Dieter); Zehender, M. (Manfred); Indolfi, C. (Ciro); F. Saia (Francesco); Fiorilli, R. (Rosario); B. Chevalier (Bernard); L. Bolognese (Leonardo); Goicolea, J. (Javier); Nie, S. (Shaoping); Y. Onuma (Yoshinobu); P.W.J.C. Serruys (Patrick); On Behalf Of The Investigators Of Absorb Ii Study,


    textabstractThe purpose of the study to assess the comparability of immediate changes in plaque/media volume (PV) on three modalities of intravascular ultrasound (IVUS) after implantation of either bioresorbable vascular scaffold (BVS) or everolimus-eluting metallic stent (EES) in Absorb II Study. T

  10. Advanced neutron absorber materials

    Branagan, Daniel J.; Smolik, Galen R.


    A neutron absorbing material and method utilizing rare earth elements such as gadolinium, europium and samarium to form metallic glasses and/or noble base nano/microcrystalline materials, the neutron absorbing material having a combination of superior neutron capture cross sections coupled with enhanced resistance to corrosion, oxidation and leaching.

  11. Absorbing Outflows in AGN

    Mathur, Smita


    The goal of this program was a comprehensive multiwavelength study of absorption phenomena in active galactic nuclei (AGN). These include a variety of associated absorption systems: X-ray warm absorbers, X-ray cold absorbers. UV absorbers with high ionization lines, MgII absorbers, red quasars and BALQSOs. The aim is to determine the physical conditions in the absorbing outflows, study their inter-relations and their role in AGN. We designed several observing programs to achieve this goal: X-ray spectroscopy, UV spectroscopy, FLAY spectroscopy and X-ray imaging. We were very successful towards achieving the goal over the five year period as shown through following observing programs and papers. Copies of a few papers are attached with this report.

  12. Bioresorbable polymeric scaffolds for coronary revascularization: Lessons learnt from ABSORB III, ABSORB China, and ABSORB Japan.

    Gogas, Bill D; King, Spencer B; Samady, Habib


    Bioresorbable polymers and biocorrodible metals are the latest developments in biodegradable materials used in interventional cardiology for the mechanical treatment of coronary atherosclerosis. Poly-L-lactic acid is the most frequently used bioresorbable polymer and initial evidence of feasibility, efficacy and clinical safety following deployment of polymer-based platforms was gained after completion of the first-in-man longitudinal ABSORB registries, Cohorts A and B and ABSORB Extend. In these studies, the biologic interaction of the first-generation Absorb Bioresorbable Vascular Scaffold (BVS) (Abbott Vascular, SC, Calif., US) with the underlying vascular tissue was evaluated in vivo with multiple imaging modalities such as intravascular ultrasound (IVUS), virtual histology-IVUS, IVUS-palpography, optical coherence tomography as well as ex vivo with coronary computed tomography. Efficacy measures following this in vivo multi-imaging assessment as well as clinical safety were comparable with current generation drug-eluting stents (DES) (Abbott Vascular, SC, Calif., US) in non-complex lesions over a 3-year follow-up. Furthermore, novel properties of functional and anatomic restoration of the vessel wall during the late phases of resorption and vascular healing were observed transforming the field of mechanical treatment of atherosclerosis from delivering only acute revascularization to additionally enable late repair and subsequent restoration of a more physiologic underlying vascular tissue. Despite the sufficient evidence and the subsequent Conformité Européenne mark approval of the first fully biodegradable scaffold (Absorb BVS) in 2012 for revascularizing non-complex lesions, the paucity of randomized comparisons of fully bioresorbable scaffolds (BRS) with metallic DES in a "real-world" clinical setting raised controversies among the interventional community for the merit of these technologies. Only recently, results from international large

  13. Multiband terahertz metamaterial absorber

    Gu Chao; Qu Shao-Bo; Pei Zhi-Bin; Xu Zhuo; Liu Jia; Gu Wei


    This paper reports the design of a multiband metamaterial (MM) absorber in the terahertz region. Theoretical and simulated results show that the absorber has four distinct and strong absorption points at 1.69, 2.76, 3.41 and that the impedance of MM could be tuned to match approximately the impedance of the free space to minimise the reflectance at absorption frequencies and large power loss exists at absorption frequencies. The distribution of the power loss indicates that the absorber is an excellent electromagnetic wave collector: the wave is first trapped and reinforced in certain specific locations and then consumed. This multiband absorber has applications in the detection of explosives and materials characterisation.

  14. TOMS Absorbing Aerosol Index

    Washington University St Louis — TOMS_AI_G is an aerosol related dataset derived from the Total Ozone Monitoring Satellite (TOMS) Sensor. The TOMS aerosol index arises from absorbing aerosols such...

  15. Electrodynamic absorber theory

    Deckert, Dirk-André


    This work deals with questions that arise in classical and quantum electrodynamics when describing the phenomena of radiation reaction and pair creation. The two guiding ideas are the absorber idea of Wheeler and Feynman (i.e. all emitted radiation will be again be absorbed by matter) and the electron sea idea of Dirac. In the first part classical dynamics are studied which allow for a description of radiation reaction without the need of renormalization. The starting point are the couple...

  16. Unidirectional perfect absorber

    Jin, L.; Wang, P.; Song, Z.


    This study proposes a unidirectional perfect absorber (UPA), which we realized with a two-arm Aharonov-Bohm interferometer, that consists of a dissipative resonator side-coupled to a uniform resonator array. The UPA has reflection-less full absorption on one direction, and reflectionless full transmission on the other, with an appropriate magnetic flux and coupling, detuning, and loss of the side-coupled resonator. The magnetic flux controls the transmission, the left transmission is larger for magnetic flux less than one-half flux quantum; and the right transmission is larger for magnetic flux between one-half and one flux quantum. Besides, a perfect absorber (PA) can be realized based on the UPA, in which light waves from both sides, with arbitrary superposition of the ampli- tude and phase, are perfectly absorbed. The UPA is expected to be useful in the design of novel optical devices.

  17. Neutron absorbing alloy

    Hayashi, Masayuki


    The neutron absorbing alloy of the present invention comprises Ti or an alloy thereof as a mother material, to which from 2 to 40% by weight of Hf and Gd within a range of from 4 to 50% by weight in total are added respectively. Ti is excellent in specific strength, corrosion resistance and workability, and produces no noxious intermetallic compound with Hf and Gd. In addition, since the alloy can incorporate a great quantity of Hf and Gd, a neutron absorbing material having excellent neutron absorbing performance than usual and excellent in specific strength, corrosion resistance and workability can be manufactured conveniently and economically not by a special manufacturing method. (T.M.)

  18. Metasurface Broadband Solar Absorber

    Azad, A K; Sykora, M; Weisse-Bernstein, N R; Luk, T S; Taylor, A J; Dalvit, D A R; Chen, H -T


    We demonstrate a broadband, polarization independent, omnidirectional absorber based on a metallic metasurface architecture, which accomplishes greater than 90% absorptance in the visible and near-infrared range of the solar spectrum, and exhibits low emissivity at mid- and far-infrared wavelengths. The complex unit cell of the metasurface solar absorber consists of eight pairs of gold nano-resonators that are separated from a gold ground plane by a thin silicon dioxide spacer. Our experimental measurements reveal high-performance absorption over a wide range of incidence angles for both s- and p-polarizations. We also investigate numerically the frequency-dependent field and current distributions to elucidate how the absorption occurs within the metasurface structure. Furthermore, we discuss the potential use of our metasurface absorber design in solar thermophotovoltaics by exploiting refractory plasmonic materials.

  19. Solar concentrator/absorber

    Von Tiesenhausen, G. F.


    Collector/energy converter, consisting of dual-slope optical concentrator and counterflow thermal energy absorber, is attached to multiaxis support structure. Efficient over wide range of illumination levels, device may be used to generate high temperature steam, serve as solar powered dryer, or power absorption cycle cooler.

  20. Optimal Sound Absorbing Structures

    Yang, Min; Fu, Caixing; Sheng, Ping


    Causal nature of the acoustic response, for any materials or structures, dictates an inequality that relates the absorption spectrum of the sample to its thickness. We present a general recipe for constructing sound-absorbing structures that can attain near-equality for the causal relation with very high absorption performance; such structures are denoted optimal. Our strategy involves using carefully designed acoustic metamaterials as backing to a thin layer of conventional sound absorbing material, e.g., acoustic sponge. By using this design approach, we have realized a 12 cm-thick structure that exhibits broadband, near-perfect flat absorption spectrum starting at around 400 Hz. From the causal relation, the calculated minimum sample thickness is 11.5 cm for the observed absorption spectrum. We present the theory that underlies such absorption performance, involving the evanescent waves and their interaction with a dissipative medium, and show the excellent agreement with the experiment.

  1. Universal metamaterial absorbe

    Smaali, Rafik; Moreau, Antoine; Taliercio, Thierry; Centeno, Emmanuel


    We propose a design for an universal absorber, characterized by a resonance frequency that can be tuned from visible to microwave frequencies independently of the choice of the metal and the dielectrics involved. An almost resonant perfect absorption up to 99.8 % is demonstrated at resonance for all polarization states of light and for a very wide angular aperture. These properties originate from a magnetic Fabry-Perot mode that is confined in a dielectric spacer of $\\lambda/100$ thickness by a metamaterial layer and a mirror. An extraordinary large funneling through nano-slits explains how light can be trapped in the structure. Simple scaling laws can be used as a recipe to design ultra-thin perfect absorbers whatever the materials and the desired resonance wavelength, making our design truly universal.

  2. Absorbable and biodegradable polymers

    Shalaby, Shalaby W


    INTRODUCTION NOTES: Absorbable/Biodegradable Polymers: Technology Evolution. DEVELOPMENT AND APPLICATIONOF NEW SYSTEMS: Segmented Copolyesters with Prolonged Strength Retention Profiles. Polyaxial Crystalline Fiber-Forming Copolyester. Polyethylene Glycol-Based Copolyesters. Cyanoacrylate-Based Systems as Tissue Adhesives. Chitosan-Based Systems. Hyaluronic Acid-Based Systems. DEVELOPMENTS IN PREPARATIVE, PROCESSING, AND EVALUATION METHODS: New Approaches to the Synthesis of Crystalline. Fiber-Forming Aliphatic Copolyesters. Advances in Morphological Development to Tailor the Performance of Me

  3. Ionized Absorbers in AGN

    Mathur, S.


    As a part of this program, we observed three AGN:PKS2251 + 113, PG0043 = 039 and PLH909. Two objects show signatures of absorbtion in their UV spectra. Based on our earlier modeling of X-ray warm absorbents, we expected to observe X-ray observation in these objects. The third, PLH909, is known to have soft excess in EINSTEIN data. Attachment: "Exploratory ASCA observation of broad absorption line quasi-stellar objects".

  4. Clustering of Absorbers

    Cristiani, S; D'Odorico, V; Fontana, A; Giallongo, E; Moscardini, L; Savaglio, S


    The observed clustering of Lyman-$\\alpha$ lines is reviewed and compared with the clustering of CIV systems. We argue that a continuity of properties exists between Lyman-$\\alpha$ and metal systems and show that the small-scale clustering of the absorbers is consistent with a scenario of gravitationally induced correlations. At large scales statistically significant over and under-densities (including voids) are found on scales of tens of Mpc.

  5. Metamaterial Absorbers in Terahertz Band

    Qi-Ye Wen; Huai-Wu Zhang; Qing-Hui Yang; Man-Man Mo


    In recent years, a great deal of effort has been made to a create terahertz (THz) wave absorber based on metamaterials (MM). Metamaterials absorbers have a variety of potential applications including thermal emitters, detector, stealth technology, phase imaging, etc. In this paper, we firstly introduce the basic structure and work principle of the THz MM absorbers, and a transmission line model is developed for devices analysis. To expand the application of THz absorbers, dual-band and broadband THz MM absorbers are designed, fabricated, and measured. At the end of this article, the future development trends of MM absorbers are discussed.

  6. Theory of microslit absorbers

    MAA Dah-You


    It is well known that narrow slit may be used as acoustical element. The exact formulae of the acoustical impedance of a narrow slit and its low-frequency approximation are available. The theory of slit is extended and a simple and practical formula is derived for the single slit. It is found that the resistance-to-reactance ratio of the slit increases to larger than one when the slit width is decreased to submillimeter range, and a panel with extremely narrow slits plus a back cavity will make an absorber with good absorption in a wide frequency range,without any porous or fibrous material. A complete theory of the microslit absorber (MSA) is, thus, presented and its absorption characteristics discussed. It is found that the MSA has essentially the same formulae as the microperforate absorber (MPA), except that the numerical coefficient of the resistance is smaller and the end correction for the mass reactance is larger for the MSA, resulting a performance inferior to that of MPA, ordinarily. Measures are proposed to compensate for these.

  7. Objective quantification of pulmonary effects in X-ray chest images; Quantificacao objetiva das sequelas pulmonares em imagens de raios-X de torax

    Oliveira, Marcela de; Giacomini, Guilherme; Alvarez, Matheus; Pereira, Paulo M.C.; Ribeiro, Sergio M.; Pina, Diana R. de [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Botucatu, SP (Brazil)


    Tuberculosis (TB) is an infectious lung disease of great concern worldwide. Even after treatment, TB leaves pulmonary sequelae that compromise the quality of life of patients. The exam of diagnostic imaging done more frequently is the X-ray chest. The evaluation of pulmonary involvement of these patients is performed visually by the radiologist. The detection and quantification aided by computer systems are of great importance for the more accurate assessment of pulmonary involvement. The objective of this study was to evaluate computationally the reduction of lung damage in X-ray of chest in patients treated with two different medication regimens. (author)

  8. Tool for objective quantification of pulmonary sequelae in monitoring of patients with tuberculosis; Ferramenta para quantificacao objetiva de sequelas pulmonares no acompanhamento de pacientes com tuberculose

    Giacomini, Guilherme; Alvarez, Matheus; Pina, Diana R. de; Bacchim Neto, Fernando A.; Pereira, Paulo C.M.; Ribeiro, Sergio M.; Miranda, Jose Ricardo de A., E-mail: [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Botucaru, SP (Brazil)


    Tuberculosis (TB), caused by Mycobacterium tuberculosis, is an ancient infectious disease that remains a global health problem. Chest radiography is the method commonly employed in assessing the evolution of TB. However, lung damage quantification methods are usually performed on a computerized tomography (CT). This objective quantification is important in the radiological monitoring of the patient by assessing the progression and treatment of TB. However, precise quantification is not feasible by the number of CT examinations necessary due to the high dose subjected to the patient and high cost to the institution. The purpose of this work is to develop a tool to quantify pulmonary sequelae caused by TB through chest X-rays. Aiming the proposed objective, a computational algorithm was developed, creating a three-dimensional representation of the lungs, with regions of dilated sequelae inside. It also made the quantification of pulmonary sequelae of these patients through CT scans performed in upcoming dates, minimizing the differences in disease progression. The measurements from the two methods were compared with results suggest that the effectiveness and applicability of the developed tool, allowing lower doses radiological monitoring of the patient during treatment.

  9. Absorber for terahertz radiation management

    Biallas, George Herman; Apeldoorn, Cornelis; Williams, Gwyn P.; Benson, Stephen V.; Shinn, Michelle D.; Heckman, John D.


    A method and apparatus for minimizing the degradation of power in a free electron laser (FEL) generating terahertz (THz) radiation. The method includes inserting an absorber ring in the FEL beam path for absorbing any irregular THz radiation and thus minimizes the degradation of downstream optics and the resulting degradation of the FEL output power. The absorber ring includes an upstream side, a downstream side, and a plurality of wedges spaced radially around the absorber ring. The wedges form a scallop-like feature on the innermost edges of the absorber ring that acts as an apodizer, stopping diffractive focusing of the THz radiation that is not intercepted by the absorber. Spacing between the scallop-like features and the shape of the features approximates the Bartlett apodization function. The absorber ring provides a smooth intensity distribution, rather than one that is peaked on-center, thereby eliminating minor distortion downstream of the absorber.

  10. Corrosion resistant neutron absorbing coatings

    Choi, Jor-Shan [El Cerrito, CA; Farmer, Joseph C [Tracy, CA; Lee, Chuck K [Hayward, CA; Walker, Jeffrey [Gaithersburg, MD; Russell, Paige [Las Vegas, NV; Kirkwood, Jon [Saint Leonard, MD; Yang, Nancy [Lafayette, CA; Champagne, Victor [Oxford, PA


    A method of forming a corrosion resistant neutron absorbing coating comprising the steps of spray or deposition or sputtering or welding processing to form a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material. Also a corrosion resistant neutron absorbing coating comprising a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material.

  11. A Perfect Terahertz Metamaterial Absorber

    Bagheri, Alireza


    In this paper the design for an absorbing metamaterial with near unity absorbance in terahertz region is presented. The absorber's unit cell structure consists of two metamaterial resonators that couple to electric and magnetic fields separately. The structure allows us to maximize absorption by varying dielectric material and thickness and, hence the effective electrical permittivity and magnetic permeability.

  12. Strategy study of quantification harmonization of SUV in PET/CT images; Estudo da estrategia de harmonizacao da quantificacao do SUV em imagens de PET/CT

    Fischer, Andreia Caroline Fischer da Silveira


    and quantitative assessments in different scopes. We concluded that the harmonization strategy of the SUV quantification presented in this paper was effective in reducing the variability of small structures quantification. However, for the comparison of SUV quantification between different scanners and institutions, it is essential that, in addition to the harmonization of quantification, the standardization of the methodology of patient preparation is maintained, in order to minimize the SUV variability due to biological factors. (author)

  13. Sensing with THz metamaterial absorbers

    Cong, Longqing


    Metamaterial perfect absorbers from microwaves to optical part of the electromagnetic spectrum has been intensely studied for its ability to absorb electromagnetic radiation. Perfect absorption of light by metamaterials have opened up new opportunities for application oriented functionalities such as efficient sensors and emitters. We present an absorber based sensing scheme at the terahertz frequencies and discuss optimized designs to achieve high frequency and amplitude sensitivities. The major advantage of a perfect metamaterial absorber as a sensor is the sensitive shift in the absorber resonance frequency along with the sharp change in the amplitude of the resonance due to strong interaction of the analyte with the electric and the magnetic fields at resonant perfect absorption frequency. We compare the sensing performance of the perfect metamaterial absorber with its complementary structural design and planar metasurface with identical structure. The best FoM values obtained for the absorber sensor here...

  14. Ferroelectrics based absorbing layers

    Hao, Jianping; Sadaune, Véronique; Burgnies, Ludovic; Lippens, Didier


    We show that ferroelectrics-based periodic structure made of BaSrTiO3 (BST) cubes, arrayed onto a metal plate with a thin dielectric spacer film exhibit a dramatic enhancement of absorbance with value close to unity. The enhancement is found around the Mie magnetic resonance of the Ferroelectrics cubes with the backside metal layer stopping any transmitted waves. It also involves quasi-perfect impedance matching resulting in reflection suppression via simultaneous magnetic and electrical activities. In addition, it was shown numerically the existence of a periodicity optimum, which is explained from surface waves analysis along with trade-off between the resonance damping and the intrinsic loss of ferroelectrics cubes. An experimental verification in a hollow waveguide configuration with a good comparison with full-wave numerical modelling is at last reported by measuring the scattering parameters of single and dual BST cubes schemes pointing out coupling effects for densely packed structures.

  15. The Flexible Bass Absorber

    Adelman-Larsen, Niels Werner; Thompson, Eric Robert; Gade, Anders Christian


    Multi-purpose concert halls face a dilemma. They host different performance types that require significantly different acoustic conditions in order to provide the best sound quality to both the performers, sound engineers and the audience. Pop and rock music often contain high levels of bass soun...... has been developed. Measurements were made on a variable and mobile low-frequency absorber. The paper presents the results of prototype sound absorption measurements as well as elements of the design.......Multi-purpose concert halls face a dilemma. They host different performance types that require significantly different acoustic conditions in order to provide the best sound quality to both the performers, sound engineers and the audience. Pop and rock music often contain high levels of bass sound...

  16. The Flexible Bass Absorber

    Adelman-Larsen, Niels Werner; Thompson, Eric Robert; Gade, Anders Christian


    Multi-purpose concert halls face a dilemma. They host different performance types that require significantly different acoustic conditions in order to provide the best sound quality to both the performers, sound engineers and the audience. Pop and rock music often contains high levels of bass sou...... has been developed. Measurements were made on a variable and mobile low-frequency absorber. The paper presents the results of prototype sound absorption measurements as well as elements of the design.......Multi-purpose concert halls face a dilemma. They host different performance types that require significantly different acoustic conditions in order to provide the best sound quality to both the performers, sound engineers and the audience. Pop and rock music often contains high levels of bass sound...

  17. Performance of Closely Spaced Point Absorbers with Constrained Floater Motion

    De Backer, G.; Vantorre, M.; Beels, C.;


    The performance of a wave energy converter array of twelve heaving point absorbers has been assessed numerically in a frequency domain model. Each point absorber is assumed to have its own linear power take-off. The impact of slamming, stroke and force restrictions on the power absorption...

  18. Liquid Hydrogen Absorber for MICE

    Ishimoto, S.; Suzuki, S.; Yoshida, M.; Green, Michael A.; Kuno, Y.; Lau, Wing


    Liquid hydrogen absorbers for the Muon Ionization Cooling Experiment (MICE) have been developed, and the first absorber has been tested at KEK. In the preliminary test at KEK we have successfully filled the absorber with {approx}2 liters of liquid hydrogen. The measured hydrogen condensation speed was 2.5 liters/day at 1.0 bar. No hydrogen leakage to vacuum was found between 300 K and 20 K. The MICE experiment includes three AFC (absorber focusing coil) modules, each containing a 21 liter liquid hydrogen absorber made of aluminum. The AFC module has safety windows to separate its vacuum from that of neighboring modules. Liquid hydrogen is supplied from a cryocooler with cooling power 1.5 W at 4.2 K. The first absorber will be assembled in the AFC module and installed in MICE at RAL.

  19. Bench Scale Process for Low Cost CO2 Capture Using a Phase-Changing Absorbent: Topical Report EH&S Risk Assessment

    Westendorf, Tiffany; Farnum, Rachel; Perry, Robert; Herwig, Mark; Giolando, Salvatore; Green, Dianne; Morall, Donna


    GE Global Research was contracted by the Department of Energy to design and build a bench-scale process for a novel phase-changing aminosilicone-based CO2 capture solvent (award number DEFE0013687). As part of this program, a technology EH&S assessment (Subtask 5.1) has been completed for a CO2 capture system for a 550 MW coal-fired power plant. The assessment focuses on two chemicals used in the process, the aminosilicone solvent, GAP-0, and dodecylbenzenesulfonic acid (DDBSA), the GAP-0 carbamate formed upon reaction of the GAP-0 with CO2, and two potential byproducts formed in the process, GAP-0/SOx salts and amine-terminated, urea-containing silicone (also referred to as “ureas” in this report). The EH&S assessment identifies and estimates the magnitude of the potential air and water emissions and solid waste generated by the process and reviews the toxicological profiles of the chemicals associated with the process. Details regarding regulatory requirements, engineering controls, and storage and handling procedures are also provided in the following sections.

  20. Improvement Of The Helmholtz Absorber

    Morrow, Duane L.


    Helmholtz-resonator system improved to enable it to absorb sound at more than one frequency without appreciable loss of effectiveness at primary frequency. Addition of annular cavities enables absorption of sound at harmonic frequencies in addition to primary frequency. Improved absorber designed for use on structures of high transmission loss. Applied to such machines as fixed-speed engines and fans.

  1. Leaf absorbance and photosynthesis

    Schurer, Kees


    The absorption spectrum of a leaf is often thought to contain some clues to the photosynthetic action spectrum of chlorophyll. Of course, absorption of photons is needed for photosynthesis, but the reverse, photosynthesis when there is absorption, is not necessarily true. As a check on the existence of absorption limits we measured spectra for a few different leaves. Two techniques for measuring absorption have been used, viz. the separate determination of the diffuse reflectance and the diffuse transmittance with the leaf at a port of an integrating sphere and the direct determination of the non-absorbed fraction with the leaf in the sphere. In a cross-check both methods yielded the same results for the absorption spectrum. The spectrum of a Fuchsia leaf, covering the short-wave region from 350 to 2500 nm, shows a high absorption in UV, blue and red, the well known dip in the green and a steep fall-off at 700 nm. Absorption drops to virtually zero in the near infrared, with subsequent absorptions, corresponding to the water absorption bands. In more detailed spectra, taken at 5 nm intervals with a 5 nm bandwidth, differences in chlorophyll content show in the different depths of the dip around 550 nm and in a small shift of the absorption edge at 700 nm. Spectra for Geranium (Pelargonium zonale) and Hibiscus (with a higher chlorophyll content) show that the upper limit for photosynthesis can not be much above 700 nm. No evidence, however, is to be seen of a lower limit for photosynthesis and, in fact, some experiments down to 300 nm still did not show a decrease of the absorption although it is well recognized that no photosynthesis results with 300 nm wavelengths.

  2. Visible light broadband perfect absorbers

    Jia, X. L.; Meng, Q. X.; Yuan, C. X.; Zhou, Z. X.; Wang, X. O., E-mail: [School of Science, Harbin Institute of Technology, Harbin 150001 (China)


    The visible light broadband perfect absorbers based on the silver (Ag) nano elliptical disks and holes array are studied using finite difference time domain simulations. The semiconducting indium silicon dioxide thin film is introduced as the space layer in this sandwiched structure. Utilizing the asymmetrical geometry of the structures, polarization sensitivity for transverse electric wave (TE)/transverse magnetic wave (TM) and left circular polarization wave (LCP)/right circular polarization wave (RCP) of the broadband absorption are gained. The absorbers with Ag nano disks and holes array show several peaks absorbance of 100% by numerical simulation. These simple and flexible perfect absorbers are particularly desirable for various potential applications including the solar energy absorber.

  3. Identification of UV-absorbing extractables from rubber closures used in containers of injectable powder and safety assessment of leachables in the drug.

    Wei, Yulei; Wu, Ying; Zhu, Tingli; Li, Zhiyan; Zhang, Yilan


    Rubber closures have been of great concern to regulatory authorities on account of their potential safety risks to patients. The aim of our work is to provide part of data about the compatibility of the injectable powder and its packaging materials for the drug registration. In this report, methodologies were established to study the system of the preparation. Firstly, three major extractables were isolated by semi-preparative HPLC method combined with silica gel-based chromatographic methods. NMR spectra including 1D NMR ((1)H, (13)C, DEPT135) and 2D NMR (COSY, HSQC, HMBC) were introduced to identify the extractables, besides HPLC, GC-MS, ESI-MS/MS and HRMS. The extractables were determined to be N-(2-(2,2,4,4-tetramethylcyclohexyl)allyl) benzo[d]thiazol-2-amine (1), 2,6-Di-tert-butyl-4-methylphenol (2) and sulfur (3) respectively. Then, to address safety concerns, approaches including QSAR analysis, the TTC and comprehensive literature evaluation methods to toxicological safety evaluation of the target compounds were established, where the safety threshold such as TTC and PDE values were developed. Finally, the migration testing of the extractables were performed to assess the leaching behavior of the rubber closures. An optimized analysis method was proposed using SPE and HPLC with an ultraviolet detector, which demonstrated good linearity, acceptable accuracy and precision. The levels of the target compounds in the powder were measured and the calculated worst case exposure of extractable 2 exceeded the TTC limit of 1.5μg/day, indicating that the products may possess potential health risks to patients. In contrast to previous studies, various NMR techniques, which were rarely applied to identify unknown extractables from rubber closures in the literature, were discussed for the structural elucidation of rubber closures extractables. Among the target compounds, extractable 1 was a new compound, whose isolation and structural elucidation were first reported here

  4. Absorbent product to absorb fluids. [for collection of human wastes

    Dawn, F. S.; Correale, J. V. (Inventor)


    A multi-layer absorbent product for use in contact with the skin to absorb fluids is discussed. The product utilizes a water pervious facing layer for contacting the skin, overlayed by a first fibrous wicking layer, the wicking layer preferably being of the one-way variety in which fluid or liquid is moved away from the facing layer. The product further includes a first container section defined by inner and outer layer of a water pervious wicking material between which is disposed a first absorbent mass. A second container section defined by inner and outer layers between which is disposed a second absorbent mass and a liquid impermeable/gas permeable layer. Spacesuit applications are discussed.

  5. Acoustic performance of membrane absorbers

    Frommhold, W.; Fuchs, H. V.; Sheng, S.


    This paper is a report on the acoustic properties of absorbing elements, which consist of metal membranes and show good sound absorption at low and medium frequencies over more than one octave. The studies refer to the sound absorption coefficient and acoustic impedance at normal incidence of the sound waves. It is shown that the behavior of the absorbing element is mainly determined by a combination of Helmholtz resonance and plate resonance. The parameters of the separate resonators are determined both by theory and experiment and serve as input data for a simplified calculation model, which can be used as an auxiliary tool for designing membrane absorber silencers.

  6. Broadband fast semiconductor saturable absorber.

    Jacobovitz-Veselka, G R; Kellerm, U; Asom, T


    Kerr lens mode-locked (KLM) solid-state lasers are typically not self-starting. We address this problem by introducing a broadband semiconductor saturable absorber that could be used as a tunable, all-solid-state, passive starting mechanism. We extend the wavelength tunability of a semiconductor saturable absorber to more than 100 nm using a band-gap-engineered low-temperature molecular-beam-epitaxy (MBE)-grown bulk AlGaAs semiconductor saturable absorber in which the absorption edge of the saturable absorber has been artificially broadened by continuously reducing the Al concentration during the MBE growth. We demonstrate its tunability and its feasibility as a starting mechanism for KLM with a picosecond resonant passive mode-locked Ti:sapphire laser. The extension to femtosecond KLM lasers has been discussed previously.

  7. Spontaneous emission and absorber theory

    Pegg, David T.


    One of the long term interests of George Series was the construction of a theory of spontaneous emission which does not involve field quantisation. His approach was written in terms of atomic operators only and he drew a parallel with the Wheeler-Feynman absorber theory of radiation. By making a particular extra postulate, he was able to obtain the correct spontaneous emission rate and the Lamb shift reasonably simply and directly. An examination of his approach indicates that this postulate is physically reasonable and the need for it arises because quantisation in his theory occurs after the response of the absorber has been accounted for by means of the radiative reaction field. We review briefly an alternative absorber theory approach to spontaneous emission based on the direct action between the emitting atom and a quantised absorber, and outline some applications to more recent effects of interest in quantum optics.

  8. Guided tissue regeneration. Absorbable barriers.

    Wang, H L; MacNeil, R L


    Over the past 15 years, techniques aimed at regeneration of lost periodontal tissue have become widely used and accepted in clinical practice. Among these techniques are those which use the principles of guided tissue regeneration (GTR), wherein barriers (i.e., membranes) are used to control cell and tissue repopulation of the periodontal wound. A variety of non-absorbable and absorbable barriers have been developed and used for this purpose, with a trend in recent years toward increased use of absorbable GTR materials. This article describes the evolution of absorbable barrier materials and overview materials available for clinical use today. In addition, advantages and disadvantages of these materials are discussed, as well as possible new developments in barrier-based GTR therapy.

  9. Test Facility for Volumetric Absorber

    Ebert, M.; Dibowski, G.; Pfander, M.; Sack, J. P.; Schwarzbozl, P.; Ulmer, S.


    Long-time testing of volumetric absorber modules is an inevitable measure to gain the experience and reliability required for the commercialization of the open volumetric receiver technology. While solar tower test facilities are necessary for performance measurements of complete volumetric receivers, the long-term stability of individual components can be tested in less expensive test setups. For the qualification of the aging effects of operating cycles on single elements of new absorber materials and designs, a test facility was developed and constructed in the framework of the KOSMOSOL project. In order to provide the concentrated solar radiation level, the absorber test facility is integrated into a parabolic dish system at the Plataforma Solar de Almeria (PSA) in Spain. Several new designs of ceramic absorbers were developed and tested during the last months. (Author)

  10. The absorber hypothesis of electrodynamics

    De Luca, Jayme


    We test the absorber hypothesis of the action-at-a-distance electrodynamics for globally-bounded solutions of a finite-particle universe. We find that the absorber hypothesis forbids globally-bounded motions for a universe containing only two charged particles, otherwise the condition alone does not forbid globally-bounded motions. We discuss the implication of our results for the various forms of electrodynamics of point charges.

  11. Power Absorption by Closely Spaced Point Absorbers in Constrained Conditions

    De Backer, G.; Vantorre, M.; Beels, C.;


    The performance of an array of closely spaced point absorbers is numerically assessed in a frequency domain model Each point absorber is restricted to the heave mode and is assumed to have its own linear power take-off (PTO) system Unidirectional irregular incident waves are considered, represent......The performance of an array of closely spaced point absorbers is numerically assessed in a frequency domain model Each point absorber is restricted to the heave mode and is assumed to have its own linear power take-off (PTO) system Unidirectional irregular incident waves are considered......, representing the wave climate at Westhinder on the Belgian Continental Shelf The impact of slamming, stroke and force restrictions on the power absorption is evaluated and optimal PTO parameters are determined For multiple bodies optimal control parameters (CP) are not only dependent on the incoming waves...

  12. Carbon Absorber Retrofit Equipment (CARE)

    Klein, Eric [Neumann Systems Group, Incorporated, Colorado Springs, CO (United States)


    During Project DE-FE0007528, CARE (Carbon Absorber Retrofit Equipment), Neumann Systems Group (NSG) designed, installed and tested a 0.5MW NeuStream® carbon dioxide (CO2) capture system using the patented NeuStream® absorber equipment and concentrated (6 molal) piperazine (PZ) as the solvent at Colorado Springs Utilities’ (CSU’s) Martin Drake pulverized coal (PC) power plant. The 36 month project included design, build and test phases. The 0.5MW NeuStream® CO2 capture system was successfully tested on flue gas from both coal and natural gas combustion sources and was shown to meet project objectives. Ninety percent CO2 removal was achieved with greater than 95% CO2product purity. The absorbers tested support a 90% reduction in absorber volume compared to packed towers and with an absorber parasitic power of less than 1% when configured for operation with a 550MW coal plant. The preliminary techno-economic analysis (TEA) performed by the Energy and Environmental Research Center (EERC) predicted an over-the-fence cost of $25.73/tonne of CO2 captured from a sub-critical PC plant.

  13. Mushroom plasmonic metamaterial infrared absorbers

    Ogawa, Shinpei; Fujisawa, Daisuke; Hata, Hisatoshi; Uetsuki, Mitsuharu; Misaki, Koji; Kimata, Masafumi


    There has been a considerable amount of interest in the development of various types of electromagnetic wave absorbers for use in different wavelength ranges. In particular, infrared (IR) absorbers with wavelength selectivity can be applied to advanced uncooled IR sensors, which would be capable of identifying objects through their radiation spectrum. In the present study, mushroom plasmonic metamaterial absorbers (MPMAs) for the IR wavelength region were designed and fabricated. The MPMAs consist of a periodic array of thin metal micropatches connected to a thin metal plate with narrow silicon (Si) posts. A Si post height of 200 nm was achieved by isotropic XeF2 etching of a thin Si layer sandwiched between metal plates. This fabrication procedure is relatively simple and is consistent with complementary metal oxide semiconductor technology. The absorption spectra of the fabricated MPMAs were experimentally measured. In addition, theoretical calculations of their absorption properties were conducted using rigorous coupled wave analysis. Both the calculated and measured absorbance results demonstrated that these MPMAs can realize strong selective absorption at wavelengths beyond the period of the array by varying the micropatch width. Absorbance values greater than 90% were achieved. Dual- or single-mode absorption can also be selected by varying the width of the Si posts. Pixel structures using such MPMAs could be used as high responsivity, high resolution and fast uncooled IR sensors.

  14. Mushroom plasmonic metamaterial infrared absorbers

    Ogawa, Shinpei, E-mail:; Fujisawa, Daisuke; Hata, Hisatoshi; Uetsuki, Mitsuharu; Misaki, Koji [Advanced Technology R and D Center, Mitsubishi Electric Corporation, 8-1-1 Tsukaguchi-Honmachi, Amagasaki, Hyogo 661-8661 (Japan); Kimata, Masafumi [College of Science and Engineering, Ritsumeikan University, 1-1-1 Noji-higashi, Kusatsu, Shiga 525-8577 (Japan)


    There has been a considerable amount of interest in the development of various types of electromagnetic wave absorbers for use in different wavelength ranges. In particular, infrared (IR) absorbers with wavelength selectivity can be applied to advanced uncooled IR sensors, which would be capable of identifying objects through their radiation spectrum. In the present study, mushroom plasmonic metamaterial absorbers (MPMAs) for the IR wavelength region were designed and fabricated. The MPMAs consist of a periodic array of thin metal micropatches connected to a thin metal plate with narrow silicon (Si) posts. A Si post height of 200 nm was achieved by isotropic XeF{sub 2} etching of a thin Si layer sandwiched between metal plates. This fabrication procedure is relatively simple and is consistent with complementary metal oxide semiconductor technology. The absorption spectra of the fabricated MPMAs were experimentally measured. In addition, theoretical calculations of their absorption properties were conducted using rigorous coupled wave analysis. Both the calculated and measured absorbance results demonstrated that these MPMAs can realize strong selective absorption at wavelengths beyond the period of the array by varying the micropatch width. Absorbance values greater than 90% were achieved. Dual- or single-mode absorption can also be selected by varying the width of the Si posts. Pixel structures using such MPMAs could be used as high responsivity, high resolution and fast uncooled IR sensors.

  15. Waveform-dependent absorbing metasurfaces

    Wakatsuchi, Hiroki; Rushton, Jeremiah J; Sievenpiper, Daniel F


    We present the first use of a waveform-dependent absorbing metasurface for high-power pulsed surface currents. The new type of nonlinear metasurface, composed of circuit elements including diodes, is capable of storing high power pulse energy to dissipate it between pulses, while allowing propagation of small signals. Interestingly, the absorbing performance varies for high power pulses but not for high power continuous waves (CWs), since the capacitors used are fully charged up. Thus, the waveform dependence enables us to distinguish various signal types (i.e. CW or pulse) even at the same frequency, which potentially creates new kinds of microwave technologies and applications.

  16. Study of an electroacoustic absorber

    Rodríguez de Antonio, Javier


    El problema de la atenuación del ruido de baja frecuencia todavía persiste pese a que ha sido ampliamente estudiado. Las técnicas para absorber ruido de alta frecuencia (superior a 500 Hz), como son los materiales porosos, resonadores de Helmholtz o espumas no ofrecen resultados aceptables a bajas frecuencias. Serían necesarios volúmenes impracticables de materiales porosos para intentar absorber frecuencias menores a 500 Hz, y lo mismo ocurre con los resonadores de Helmholtz. Esta ineficacia...

  17. Oil and fat absorbing polymers

    Marsh, H. E., Jr. (Inventor)


    A method is described for forming a solid network polymer having a minimal amount of crosslinking for use in absorbing fats and oils. The polymer remains solid at a swelling ratio in oil or fat of at least ten and provides an oil absorption greater than 900 weight percent.

  18. Insight into magnetorheological shock absorbers

    Gołdasz, Janusz


    This book deals with magnetorheological fluid theory, modeling and applications of automotive magnetorheological dampers. On the theoretical side a review of MR fluid compositions and key factors affecting the characteristics of these fluids is followed by a description of existing applications in the area of vibration isolation and flow-mode shock absorbers in particular. As a majority of existing magnetorheological devices operates in a so-called flow mode a critical review is carried out in that regard. Specifically, the authors highlight common configurations of flow-mode magnetorheological shock absorbers, or so-called MR dampers that have been considered by the automotive industry for controlled chassis applications. The authors focus on single-tube dampers utilizing a piston assembly with one coil or multiple coils and at least one annular flow channel in the piston.

  19. Detection of IgM antibodies against Toxoplasma gondii in blood samples absorbed onto filter paper, in order to assess a baseline for the occurence of congenital toxoplasma infections

    Conyn-van Spaendonck MAE; van Knapen F


    This report deals in the first place with some investigations on the utility of blood samples absorbed onto filter paper for determination of antibodies to Toxoplasma gondii. Secondly, the results of specific IgM detection in such samples of a cohort of neonates born in 1986/1987 are reported. The

  20. Optimum thickness of Mossbauer absorber


    If recoilless fraction fa is available, the optimum absorber thickness dopt can be calculated by maximizing the signal to noise ratio or Q factor. In this work,an approach presented is to get experimental Qexp as a function of the thickness, and then fitting Qexp by its theoretical expression gives fa value. At last the dopt value is deduced from a maximum on the fitted curve. In such a way, thicknesses of six specimens with quadrupole or magnetic hyperfine splitting were optimized.

  1. Plasmonic titanium nitride nanostructures for perfect absorbers

    Guler, Urcan; Li, Wen-Wei; Kinsey, Nathaniel


    We propose a metamaterial based perfect absorber in the visible region, and investigate the performance of titanium nitride as an alternative plasmonic material. Numerical and experimental results reveal that titanium nitride performs better than gold as a plasmonic absorbing material...

  2. Remarks on Wheeler-Feynman absorber theory

    Gründler, Gerold


    The derivation of absorber theory is outlined in very detail. Absorber theory is based on classical action-at-a-distance electrodynamics, but it deviates from that theory at a crucial point. It is shown that (a) absorber theory cannot achieve any of it's essential results without this deviation, and that (b) this deviation restricts the application range of absorber theory to stationary radiation processes. Furthermore an error which crept into Wheeler's and Feynman's interpretation of their ...

  3. A randomised controlled trial of absorbable versus non-absorbable sutures for skin closure after open carpal tunnel release.

    Theopold, C


    We compared the aesthetic outcome of scars after closure of open carpal tunnel incisions with either absorbable 4-0 Vicryl Rapide or non-absorbable 4-0 Novafil. Patients were recruited in a randomized controlled trial and scars were scored at 6 weeks using a modified Patient and Observer Scar Assessment Scale. Scores demonstrated differences only for pain, vascularity and cross-hatching between both groups, though none of these were statistically significant. The dissolving and falling out of Vicryl Rapide was significantly more comfortable than removal of 4-0 Novafil sutures, assessed on a numerical analogue scale. There was no difference in infection rate between both study groups, supporting overall the use of Vicryl Rapide for the closure of palmar hand incisions, in light of the convenience and cost savings associated with absorbable sutures.

  4. Synchrotron radiation absorber for high density loads

    Anashin, V. V.; Kuzminych, V. S.; Trakhtenberg, E. M.; Zholents, A. A.


    A design of a special synchrotron radiation absorber for the storage ring VEPP-4M is presented. The density of the synchrotron radiation power on the absorber surface is up to 500 W/mm 2. The absorber is made from a beryllium plate, brazed inside to the copper vacuum chamber, which is intensively water-cooled from outside.

  5. Piezooptic effect of absorbing environment

    Ю. А. Рудяк


    Full Text Available Application of piezooptic effect of absorbing environment for the definition of the parameter of stress deformation state was examined. The analysis of dielectric permeability tensor of imaginary parts was done. It is shown that changes in the real part dielectric permeability tensor mainly the indicator of fracture was fixed by means of mechanics interference methods and the changes in the imaginary part (α – real rate of absorption can be measured by means of analysis of light absorption and thus stress deformation state can be determined

  6. Porcelain enamel neutron absorbing material

    Iverson, Daniel C.


    A porcelain enamel composition as a neutron absorbing material can be prepared of a major proportion by weight of a cadmium compound and a minor proportion of compounds of boron, lithium and silicon. These compounds in the form of a porcelain enamel coating or layer on several alloys has been found to be particularly effective in enhancing the nuclear safety of equipment for use in the processing and storage of fissile material. The composition of the porcelain enamel coating can be tailored to match the coefficient of thermal expansion of the equipment to be coated and excellent coating adhesion can be achieved.

  7. Carbon dioxide absorbents for rebreather diving.

    Pennefather, John


    Firstly I would like to thank SPUMS members for making me a Life Member of SPUMS; I was surprised and greatly honoured by the award. I also want to confirm and expand on the findings on carbon dioxide absorbents reported by David Harvey et al. For about 35 years, I was the main player in deciding which absorbent went into Australian Navy and Army diving sets. On several occasions, suppliers of absorbents to the anaesthesia market tried to supply the Australian military market. On no occasion did they provide absorbent that came close to the minimum absorbent capacity required, generally being 30-40% less efficient than diving-grade absorbents. Because I regard lives as being more important than any likely dollar saving, the best absorbent was always selected unless two suppliers provided samples with the same absorbent capacity. On almost every occasion, there was a clear winner and cost was never considered. I suggest the same argument for the best absorbent should be used by members and their friends who dive using rebreather sets. I make this point because of my findings on a set that was brought to me after the death of its owner. The absorbent was not the type or grain size recommended by the manufacturer of the set and did not resemble any of the diving grade absorbents I knew of. I suspected by its appearance that it was anaesthetic grade absorbent. When I tested the set, the absorbent system failed very quickly so it is likely that carbon dioxide toxicity contributed to his death. The death was not the subject of an inquest and I have no knowledge of how the man obtained the absorbent. Possibly there was someone from an operating theatre staff who unintentionally caused their friend's death by supplying him with 'borrowed absorbent'. I make this point as I would like to discourage members from making a similar error.

  8. A polarization-independent broadband terahertz absorber

    Shi, Cheng; Zang, XiaoFei, E-mail:, E-mail:; Wang, YiQiao; Chen, Lin; Cai, Bin; Zhu, YiMing, E-mail:, E-mail: [Shanghai Key Laboratory of Modern Optical System and Engineering Research Center of Optical Instrument and System, Ministry of Education, University of Shanghai for Science and Technology, Shanghai 200093 (China)


    A highly efficient broadband terahertz absorber is designed, fabricated, and experimentally as well as theoretically evaluated. The absorber comprises a heavily doped silicon substrate and a well-designed two-dimensional grating. Due to the destructive interference of waves and diffraction, the absorber can achieve over 95% absorption in a broad frequency range from 1 to 2 THz and for angles of incidence from 0° to 60°. Such a terahertz absorber is also polarization-independent due to its symmetrical structure. This omnidirectional and broadband absorber have potential applications in anti-reflection coatings, imaging systems, and so on.

  9. Remarks on Wheeler-Feynman absorber theory

    Gründler, Gerold


    The derivation of absorber theory is outlined in very detail. Absorber theory is based on classical action-at-a-distance electrodynamics, but it deviates from that theory at a crucial point. It is shown that (a) absorber theory cannot achieve any of it's essential results without this deviation, and that (b) this deviation restricts the application range of absorber theory to stationary radiation processes. Furthermore an error which crept into Wheeler's and Feynman's interpretation of their equation (19) is pointed out. These shortcomings can probably be eliminated by a quantum-theoretical formulation of absorber theory.

  10. Multi-channel coherent perfect absorbers

    Bai, Ping


    The absorption efficiency of a coherent perfect absorber usually depends on the phase coherence of the incident waves on the surfaces. Here, we present a scheme to create a multi-channel coherent perfect absorber in which the constraint of phase coherence is loosened. The scheme has a multi-layer structure such that incident waves in different channels with different angular momenta can be simultaneously and perfectly absorbed. This absorber is robust in achieving high absorption efficiency even if the incident waves become "incoherent" and possess "random" wave fronts. Our work demonstrates a unique approach to designing highly efficient metamaterial absorbers. © CopyrightEPLA, 2016.

  11. Analysis and evaluation of RF absorbing material in suppressing modes associated with a metallic cavity

    Green, David L.

    Application of absorbing materials within enclosures designed to house high-speed digital electronics has become common practice for suppressing resonances associated with the enclosure geometry. Use of absorbing material is often considered toward the end of the design phase when the product is undergoing electromagnetic compatibility compliance testing, leaving little time for the additional experimentation required to optimize absorber material selection or placement within the device. The engineering principles required for maximizing absorber performance within the enclosure are often disregarded, replaced by a "shotgun" approach where multiple material options are experimented with until a solution is achieved. For this research a frequency domain reverberation chamber technique and one-port time domain quality factor estimation technique are employed to quantify the ability of various absorbing materials to suppress resonances of a physically small, electrically large cavity representative of those that may be used to enclose high-speed circuitry. Using both measurement techniques, assessment of the performance of various absorbing materials was performed as well as an evaluation of the affect absorber position has on overall material performance. It was found that both measurement techniques were effective in quantifying absorber performance within the cavity. For the frequency domain reverberation chamber approach the absorber effectiveness, defined as the difference in insertion loss between the cavity with and without absorbing material, was analyzed for various materials. For the undermoded cavity it was found that absorber effectiveness was positionally dependent. For the overmoded cavity, however, the position of the absorber within the cavity, as long as the total exposed surface area remained constant, did not have a significant impact on the absorber effectiveness. Similar results were also found by comparing the estimated quality factor for

  12. Energy-Absorbing Beam Member

    Littell, Justin D. (Inventor)


    An energy-absorbing (EA) beam member and having a cell core structure is positioned in an aircraft fuselage proximate to the floor of the aircraft. The cell core structure has a length oriented along a width of the fuselage, a width oriented along a length of the fuselage, and a depth extending away from the floor. The cell core structure also includes cell walls that collectively define a repeating conusoidal pattern of alternating respective larger and smaller first and second radii along the length of the cell core structure. The cell walls slope away from a direction of flight of the aircraft at a calibrated lean angle. An EA beam member may include the cell core structure and first and second plates along the length of the cell core structure on opposite edges of the cell material.

  13. Numerical simulations of quasar absorbers

    Theuns, T


    The physical state of the intergalactic medium can be probed in great detail with the intervening absorption systems seen in quasar spectra. The properties of the Hydrogen absorbers depend on many cosmological parameters, such as the matter-power spectrum, reionisation history, ionising background and the nature of the dark matter. The spectra also contain metal lines, which can be used to constrain the star formation history and the feedback processes acting in large and small galaxies. Simulations have been instrumental in investigating to what extent these parameters can be unambiguously constrained with current and future data. This paper is meant as an introduction to this subject, and reviews techniques and methods for simulating the intergalactic medium.

  14. Warm Absorbers in Active Galactic Nuclei

    Komossa, S


    We first provide a review of the properties of warm absorbers concentrating on what we have learned from ROSAT and ASCA. This includes dusty and dust-free warm absorbers, non-X-ray emission and absorption features of warm absorbers, and the possible warm absorber interpretation of the peculiar 1.1 keV features. We then discuss facets of warm absorbers by a more detailed investigation of individual objects: In a first part, we discuss several candidates for dusty warm absorbers. In a second part, we review and extend our earlier study of a possible relation between warm absorber and CLR in NGC 4051, and confirm that both components are of different origin (the observed coronal lines are underpredicted by the models, the warm absorber is too highly ionized). We then suggest that a potential overprediction of these lines in more lowly ionized absorbers can be avoided if these warm absorbers are dusty. In a third part, we present first results of an analysis of a deep ROSAT PSPC observation of the quasar MR2251-1...

  15. Multiband Negative Permittivity Metamaterials and Absorbers

    Yiran Tian


    Full Text Available Design and characteristics of multiband negative permittivity metamaterial and its absorber configuration are presented in this paper. The proposed multiband metamaterial is composed of a novel multibranch resonator which can possess four electric resonance frequencies. It is shown that, by controlling the length of the main branches of such resonator, the resonant frequencies and corresponding absorbing bands of metamaterial absorber can be shifted in a large frequency band.

  16. Multiobjective Topology Optimization of Energy Absorbing Materials


    125–143 DOI 10.1007/s00158-014-1117-8 RESEARCH PAPER Multiobjective topology optimization of energy absorbing materials Raymond A. Wildman · George A...recent developments. J Multiscale Model 3(4):1–42 Qiao P, Yang M, Bobaru F (2008) Impact mechanics and high-energy absorbing materials: review . J Aerosp...ARL-RP-0533 ● AUG 2015 US Army Research Laboratory Multiobjective Topology Optimization of Energy Absorbing Materials by

  17. A Six-Fold Symmetric Metamaterial Absorber

    Humberto Fernández Álvarez


    Full Text Available A novel microwave metamaterial absorber design is introduced along with its manufacturing and characterization. Significant results considering both bandwidth and angular stability are achieved. Parametric analysis and simplified equivalent circuit are provided to give an insight on the key elements influencing the absorber performance. In addition, the constitutive parameters of the effective medium model are obtained and related to the absorber resonant behavior. Moreover, a new thinner and more flexible absorber version, preserving broad bandwidth and angular insensitive performance, is simulated, and an 8 × 8 unit-cells prototype is manufactured and measured for a limited angular margin in an anechoic chamber.

  18. Nonlinear dynamic vibration absorbers with a saturation

    Febbo, M.; Machado, S. P.


    The behavior of a new type of nonlinear dynamic vibration absorber is studied. A distinctive characteristic of the proposed absorber is the impossibility to extend the system to infinity. The mathematical formulation is based on a finite extensibility nonlinear elastic potential to model the saturable nonlinearity. The absorber is attached to a single degree-of-freedom linear/nonlinear oscillator subjected to a periodic external excitation. In order to solve the equations of motion and to analyze the frequency-response curves, the method of averaging is used. The performance of the FENE absorber is evaluated considering a variation of the nonlinearity of the primary system, the damping and the linearized frequency of the absorber and the mass ratio. The numerical results show that the proposed absorber has a very good efficiency when the nonlinearity of the primary system increases. When compared with a cubic nonlinear absorber, for a large nonlinearity of the primary system, the FENE absorber shows a better effectiveness for the whole studied frequency range. A complete absence of quasi-periodic oscillations is also found for an appropriate selection of the parameters of the absorber. Finally, direct integrations of the equations of motion are performed to verify the accuracy of the proposed method.

  19. Absorbent product and articles made therefrom

    Dawn, F. S.; Correale, J. V. (Inventor)


    A multilayer absorbent product for use in contact with the skin to absorb fluids is described. The product has a water pervious facing layer for contacting the skin, and a first fibrous wicking layer overlaying the water pervious layer. A first container section is defined by inner and outer layers of a water pervious wicking material in between a first absorbent mass and a second container section defined by inner and outer layers of a water pervious wicking material between what is disposed a second absorbent mass, and a liquid impermeable/gas permeable layer overlaying the second fibrous wicking layer.

  20. Metamaterial absorber with random dendritic cells

    Zhu, Weiren; Zhao, Xiaopeng


    The metamaterial absorber composed of random dendritic cells has been investigated at microwave frequencies. It is found that the absorptivities come to be weaker and the resonant frequency get red shift as the disordered states increasing, however, the random metamaterial absorber still presents high absorptivity more than 95%. The disordered structures can help understanding of the metamaterial absorber and may be employed for practical design of infrared metamaterial absorber, which may play important roles in collection of radiative heat energy and directional transfer enhancement.

  1. Comments on liquid hydrogen absorbers for MICE

    Green, Michael A.


    This report describes the heat transfer problems associatedwith a liquid hydrogen absorber for the MICE experiment. This reportdescribes a technique for modeling heat transfer from the outside world,to the abosrber case and in its vacuum vessel, to the hydrogen and theninto helium gas at 14 K. Also presented are the equation for freeconvection cooling of the liquid hydrogen in the absorber.

  2. An ultrathin dual-band metamaterial absorber

    Zhang, Yong; Duan, Junping; Zhang, Wendong; Wang, Wanjun; Zhang, Binzhen


    The design and preparation of an ultrathin dual-band metamaterial absorber whose resonant frequency located at radar wave (20 GHz-60 GHz) is presented in this paper. The absorber is composed of a 2-D periodic sandwich featured with two concentric annuluses. The influence on the absorber's performance produced by resonant cell's structure size and material parameters was numerically simulated and analyzed based on the standard full wave finite integration technology in CST. Laser ablation process was adopted to prepare the designed absorber on epoxy resin board coated with on double plane of copper with a thickness that is 1/30 and 1/50 of the resonant wavelength at a resonant frequency of 30.51 GHz and 48.15 GHz. The full width at half maximum (FWHM) reached 2.2 GHz and 2.35 GHz and the peak of the absorptance reached 99.977%. The ultrathin absorber is nearly omnidirectional for all polarizations. The test results of prepared sample testify the designed absorber's excellent absorbing performance forcefully. The absorber expands inspirations of radar stealth in military domain due to its flexible design, cost-effective and other outstanding properties.

  3. 21 CFR 872.6050 - Saliva absorber.


    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Saliva absorber. 872.6050 Section 872.6050 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6050 Saliva absorber. (a) Identification. A saliva...

  4. Tuned mass absorber on a flexible structure

    Krenk, Steen; Høgsberg, Jan Becker


    The classic design of a tuned mass absorber is based on a simple two-mass analogy in which the tuned mass is connected to the structural mass with a spring and a viscous damper. In a flexible multi-degree-of-freedom structure the tuned mass absorber is typically introduced to provide damping of a...

  5. [Absorbed doses in dental radiology].

    Bianchi, S D; Roccuzzo, M; Albrito, F; Ragona, R; Anglesio, S


    The growing use of dento-maxillo-facial radiographic examinations has been accompanied by the publication of a large number of studies on dosimetry. A thorough review of the literature is presented in this article. Most studies were carried out on tissue equivalent skull phantoms, while only a few were in vivo. The aim of the present study was to evaluate in vivo absorbed doses during Orthopantomography (OPT). Full Mouth Periapical Examination (FMPE) and Intraoral Tube Panoramic Radiography (ITPR). Measurements were made on 30 patients, reproducing clinical conditions, in 46 anatomical sites, with 24 intra- and 22 extra-oral thermoluminiscent dosimeters (TLDS). The highest doses were measured, in orthopantomography, at the right mandibular angle (1899 mu Gy) in FMPE on the right naso-labial fold (5640 mu Gy and in ITPR on the palatal surface of the left second upper molar (1936 mu Gy). Intraoral doses ranged from 21 mu Gy, in orthopantomography, to 4494 mu Gy in FMPE. Standard errors ranged from 142% in ITPR to 5% in orthopantomography. The highest rate of standard errors was found in FMPE and ITPR. The data collected in this trial are in agreement with others in major literature reports. Disagreements are probably due to different exam acquisition and data collections. Such differences, presented comparison in several sites, justify lower doses in FMPE and ITPR. Advantages and disadvantages of in vivo dosimetry of the maxillary region are discussed, the former being a close resemblance to clinical conditions of examination and the latter the impossibility of collecting values in depth of tissues. Finally, both ITPR and FMPE required lower doses than expected, and can be therefore reconsidered relative to their radiation risk.

  6. Quantification of decreasing of human health risk by bioremediation of a contaminated soil with petroleum hydrocarbons; Quantificacao do decrescimo de risco associado a biorremediacao de um solo contaminado por hidrocarbonetos de petroleo

    Lima, Cristiane A.; Castilhos, Zuleica C.; Rizzo, Andrea C.L. [Centro de Tecnologia Mineral (CETEM), Rio de Janeiro, RJ (Brazil); Leite, Selma G.F. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Escola de Quimica


    The main objective of this work was to evaluate the efficiency of four different bioremediation processes in the decrease of organic pollutants present in a soil contaminated with crude oil, using a toxicological approach based on the human health risk assessment methodology (USEPA, 1989). The different techniques of bioremediation utilized (biostimulation, bioaugmentation and addition of enzymatic solution) were efficient in the removal of the organic pollutants, especially of PAHs, considered highly recalcitrant. In the human health risk assessment, the exposure pathway that resulted in higher hazards of no-carcinogenic effects and risks of carcinogenic effects in the population (children and adult) was dermal contact with soil. The pollutant that contributed more in the different exposure pathways was benzo(a)pyrene. When carcinogenic and no-carcinogenic effects in children and adults were evaluated, the different treatments showed efficiency, once they were capable to reduce the risk and the hazard index (HI) bellow target levels (< 1 x 10{sup -4} and 1, respectively), showing that these treatments were efficient to decrease the potential damage in the exposed population. (author)

  7. Selecting appropriate absorbent products to treat urinary incontinence.

    Payne, Drew


    Urinary incontinence can have a significant negative effect on a person's life, especially if left unmanaged and untreated. Continence assessment, often carried out by community nurses, is an important element in the management of a person's urinary incontinence, and so is the selection of appropriate absorbent incontinence pads. This article reviews: the causes and effects of urinary incontinence; how to derive the most appropriate information from a continence assessment; strategies for selecting incontinence pads for a person, on the basis of the results of the continence assessment; and some of the problems and risks associated with the use of incontinence pads.

  8. Quantification of Mycosphaerella fijiensis in vitro growth by absorbance readings

    Mileidy Cruz-Martín


    Full Text Available The slow growth of Mycosphaerella fijiensis Morelet in synthetic and semi-synthetic media as well as the characteristics of their colonies makes the use of traditional methods for evaluating the fungal growth are inadequate and impractical. Therefore, it requires a method to quantify growth in small volumes of substance and in short periods of time. The aim of this study was to quantify the M. fijiensis growth, through absorbance readings on the time, of mycelial suspensions obtained from cultures in liquid medium. Mycelial dry weight of the pathogen grown in liquid culture in flasks of 250 ml capacity and the absorbance in 96 well plates was compared. Similar procedure was used to evaluate the effect of bacterial culture filtrates with in vitro antifungal activity against M. fijiensis. A linear relationship between absorbance at 595 nm of fungal growth in liquid culture medium with respect to the dry mass was found. Absorbance readings using 96-well plates were possible to quantify the M. fijiensis mycelial suspensions growth in liquid culture. Also, there may be applied to assess the growth inhibition of the pathogen for bacterial culture filtrates with results at 48 h incubation. Key words: antifungal activity assay, biomass, DO595

  9. Performance of a Multifunctional Space Evaporator-Absorber-Radiator (SEAR)

    Izenson, Michael G.; Chen, Weibo; Phillips, Scott; Chepko, Ariane; Bue, Grant; Quinn, Gregory


    The Space Evaporator-Absorber-Radiator (SEAR) is a nonventing thermal control subsystem that combines a Space Water Membrane Evaporator (SWME) with a Lithium Chloride Absorber Radiator (LCAR). The LCAR is a heat pump radiator that absorbs water vapor produced in the SWME. Because of the very low water vapor pressure at equilibrium with lithium chloride solution, the LCAR can absorb water vapor at a temperature considerably higher than the SWME, enabling heat rejection sufficient for most EVA activities by thermal radiation from a relatively small area radiator. Prior SEAR prototypes used a flexible LCAR that was designed to be installed on the outer surface of a portable life support system (PLSS) backpack. This paper describes a SEAR subsystem that incorporates a very compact LCAR. The compact, multifunctional LCAR is built in the form of thin panels that can also serve as the PLSS structural shell. We designed and assembled a 2 ft² prototype LCAR based on this design and measured its performance in thermal vacuum tests when supplied with water vapor by a SWME. These tests validated our models for SEAR performance and showed that there is enough area available on the PLSS backpack shell to enable rejection of metabolic heat from the LCAR. We used results of these tests to assess future performance potential and suggest approaches for integrating the SEAR system with future space suits.

  10. Design of a nonlinear torsional vibration absorber

    Tahir, Ammaar Bin

    Tuned mass dampers (TMD) utilizing linear spring mechanisms to mitigate destructive vibrations are commonly used in practice. A TMD is usually tuned for a specific resonant frequency or an operating frequency of a system. Recently, nonlinear vibration absorbers attracted attention of researchers due to some potential advantages they possess over the TMDs. The nonlinear vibration absorber, or the nonlinear energy sink (NES), has an advantage of being effective over a broad range of excitation frequencies, which makes it more suitable for systems with several resonant frequencies, or for a system with varying excitation frequency. Vibration dissipation mechanism in an NES is passive and ensures that there is no energy backflow to the primary system. In this study, an experimental setup of a rotational system has been designed for validation of the concept of nonlinear torsional vibration absorber with geometrically induced cubic stiffness nonlinearity. Dimensions of the primary system have been optimized so as to get the first natural frequency of the system to be fairly low. This was done in order to excite the dynamic system for torsional vibration response by the available motor. Experiments have been performed to obtain the modal parameters of the system. Based on the obtained modal parameters, the design optimization of the nonlinear torsional vibration absorber was carried out using an equivalent 2-DOF modal model. The optimality criterion was chosen to be maximization of energy dissipation in the nonlinear absorber attached to the equivalent 2-DOF system. The optimized design parameters of the nonlinear absorber were tested on the original 5-DOF system numerically. A comparison was made between the performance of linear and nonlinear absorbers using the numerical models. The comparison showed the superiority of the nonlinear absorber over its linear counterpart for the given set of primary system parameters as the vibration energy dissipation in the former is

  11. Practical absorption limits of MPP absorber

    MAA Dah-You


    The construction and properties of microperforated panel (MPP) absorber are discussed. The absorption limit of the absorber had been shown that low values of the perforate constant k = d(f/10)1/2 and the orifice diameter d (in mm) are essential for MPP to have high absorption in wide frequency band. To find the exact limits, take 1 for k as a start, because both specific resistance and high absorption require k around one. And the orifice diameter d is chosen as 0.1 mm, so that the peak absorption coefficient (resonance absorption) is at 1000 Hz,and high sound frequency may be in the absorption region. Is it possible for a single layer of such an MPP to cover the whole absorption region required in practice? The half-absorption limit is not a good criterion, because low absorption comes in also in some cases. The 0.5 absorption coefficient limit is suggested for practical region, as a standard for comparison. Absorption curves were drawn for different load resistances, of absorption coefficients versus frequency.Ordinary MPP absorber absorbs in slightly over two octaves, and the new absorber with r = 1 (specific resistance equal to the characteristic impedance in air)is slightly better than these, 2.5 octaves. The new absorbers with r > 1, are much better than these, and some satisfies high absorption in broad frequency range. Realization of these will mean great progress of MPP absorbers.

  12. Assessment of the absorption process following bioabsorbable everolimus-eluting stent implantation: Temporal changes in strain values and tissue composition using intravascular ultrasound radiofrequency data analysis A substudy of the ABSORB clinical trial

    H.M. Garcia-Garcia (Hector); N. Gonzalo (Nieves); R. Pawar (Ravindra); N. Kukreja (Neville); D. Dudek (Dariusz); L. Thuesen (Leif); J.A. Ormiston (John); E.S. Regar (Eveline); P.W.J.C. Serruys (Patrick)


    textabstractAims: The main objective was to use IVUS-backscatter radiofrequency (IVUS-RF) to assess the degradation of a bioabsorbable stent by measuring serial changes in dense calcium (DC) and necrotic core (NC) as assessed by intravascular ultrasound-Virtual Histology™ (IVUS-VH) and in the strain

  13. Absorbed dose by a CMOS in radiotherapy

    Borja H, C. G.; Valero L, C. Y.; Guzman G, K. A.; Banuelos F, A.; Hernandez D, V. M.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Calle Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Paredes G, L. C., E-mail: [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)


    Absorbed dose by a complementary metal oxide semiconductor (CMOS) circuit as part of a pacemaker, has been estimated using Monte Carlo calculations. For a cancer patient who is a pacemaker carrier, scattered radiation could damage pacemaker CMOS circuits affecting patient's health. Absorbed dose in CMOS circuit due to scattered photons is too small and therefore is not the cause of failures in pacemakers, but neutron calculations shown an absorbed dose that could cause damage in CMOS due to neutron-hydrogen interactions. (Author)

  14. Graphene and Graphene Metamaterials for Terahertz Absorbers

    Andryieuski, Andrei; Pizzocchero, Filippo; Booth, Tim


    Graphene, due to the possibility to tune its conductivity, is the promising material for a range of the terahertz (THz) applications, such as tunable reflectors, absorbers, modulators, filters and polarization converters. Subwavelength structuring of graphene in order to form metamaterials allows...... for even more control over the THz waves. In this poster presentation I will show an elegant way to describe the graphene metamaterials and the design of graphene based absorbers. I will also present our recent experimental results on the graphene absorbers characterization....

  15. The nonlinear piezoelectric tuned vibration absorber

    Soltani, P.; Kerschen, G.


    This paper proposes a piezoelectric vibration absorber, termed the nonlinear piezoelectric tuned vibration absorber (NPTVA), for the mitigation of nonlinear resonances of mechanical systems. The new feature of the NPTVA is that its nonlinear restoring force is designed according to a principle of similarity, i.e., the NPTVA should be an electrical analog of the nonlinear host system. Analytical formulas for the NPTVA parameters are derived using the homotopy perturbation method. Doing so, a nonlinear generalization of Den Hartog’s equal-peak tuning rule is developed for piezoelectric vibration absorbers.

  16. Design and application of functional absorbers

    WANG Jiqing


    This paper gives an overview of the research at Institute of Acoustics, Tongji University, on functional absorbers and experience acquired in practical applications over the past three decades. Experiments and analysis of the absorption characteristics of three different geometrical forms of functional absorbers, i.e., panels, cubes and tubes, were conducted with different arrangements. The resulting esthetical effects are illustrated with pictures. Several non-fiber materials are used to compose functional absorbers with advantages both in acoustic properties and in architectural features. Cost effectiveness analysis is also given in order to provide design guidelines.

  17. Absorbed Energy in Ship Collisions and Grounding

    Pedersen, Preben Terndrup; Zhang, Shengming


    is that the absorbed energy does not depend on the arrangement of the structure, the material properties, and the damage mode.The purpose of the present paper is to establish a new simple relation between the absorbed energy and the destroyed material volume, which can be used as a design tool for analysis of ship......Minorsky's well-known empirical formula, which relates the absorbed energy to the destroyed material volume, has been widely used in analyses of high energy collision and grounding accidents for nearly 40 years. The advantage of the method is its apparent simplcity. Obviously, its drawback...

  18. Absorbed dose by a CMOS in radiotherapy

    Borja H, C. G.; Valero L, C. Y.; Guzman G, K. A.; Banuelos F, A.; Hernandez D, V. M.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Calle Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Paredes G, L. C., E-mail: [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)


    Absorbed dose by a complementary metal oxide semiconductor (CMOS) circuit as part of a pacemaker, has been estimated using Monte Carlo calculations. For a cancer patient who is a pacemaker carrier, scattered radiation could damage pacemaker CMOS circuits affecting patient's health. Absorbed dose in CMOS circuit due to scattered photons is too small and therefore is not the cause of failures in pacemakers, but neutron calculations shown an absorbed dose that could cause damage in CMOS due to neutron-hydrogen interactions. (Author)

  19. Absorbed dose rate in air in metropolitan Tokyo before the Fukushima Daiichi Nuclear Power Plant accident.

    Inoue, K; Hosoda, M; Fukushi, M; Furukawa, M; Tokonami, S


    The monitoring of absorbed dose rate in air has been carried out continually at various locations in metropolitan Tokyo after the accident of the Fukushima Daiichi Nuclear Power Plant. While the data obtained before the accident are needed to more accurately assess the effects of radionuclide contamination from the accident, detailed data for metropolitan Tokyo obtained before the accident have not been reported. A car-borne survey of the absorbed dose rate in air in metropolitan Tokyo was carried out during August to September 2003. The average absorbed dose rate in air in metropolitan Tokyo was 49±6 nGy h(-1). The absorbed dose rate in air in western Tokyo was higher compared with that in central Tokyo. Here, if the absorbed dose rate indoors in Tokyo is equivalent to that outdoors, the annual effective dose would be calculated as 0.32 mSv y(-1).

  20. Structural and optical properties of copper-coated substrates for solar thermal absorbers

    Pratesi, Stefano; De Lucia, Maurizio; Meucci, Marco; Sani, Elisa


    Spectral selectivity, i.e. merging a high absorbance at sunlight wavelengths to a low emittance at the wavelengths of thermal spectrum, is a key characteristics for materials to be used for solar thermal receivers. It is known that spectrally selective absorbers can raise the receiver efficiency for all solar thermal technologies. Tubular sunlight receivers for parabolic trough collector (PTC) systems can be improved by the use of spectrally selective coatings. Their absorbance is increased by deposing black films, while the thermal emittance is minimized by the use of properly-prepared substrates. In this work we describe the intermediate step in the fabrication of black-chrome coated solar absorbers, namely the fabrication and characterization of copper coatings on previously nickel-plated stainless steel substrates. We investigate the copper surface features and optical properties, correlating them to the coating thickness and to the deposition process, in the perspective to assess optimal conditions for solar absorber applications.

  1. Space Compatible Radar Absorbing Materials Project

    National Aeronautics and Space Administration — This SBIR Phase 1 project shall investigate novel radar absorbing materials (RAM) for use in space or simulated space environments. These materials are lightweight...

  2. An ultra-broadband multilayered graphene absorber

    Amin, Muhammad


    An ultra-broadband multilayered graphene absorber operating at terahertz (THz) frequencies is proposed. The absorber design makes use of three mechanisms: (i) The graphene layers are asymmetrically patterned to support higher order surface plasmon modes that destructively interfere with the dipolar mode and generate electromagnetically induced absorption. (ii) The patterned graphene layers biased at different gate voltages backedup with dielectric substrates are stacked on top of each other. The resulting absorber is polarization dependent but has an ultra-broadband of operation. (iii) Graphene\\'s damping factor is increased by lowering its electron mobility to 1000cm 2=Vs. Indeed, numerical experiments demonstrate that with only three layers, bandwidth of 90% absorption can be extended upto 7THz, which is drastically larger than only few THz of bandwidth that can be achieved with existing metallic/graphene absorbers. © 2013 Optical Society of America.

  3. Semiconductor saturable absorbers for ultrafast THz signals

    Hoffmann, Matthias C.; Turchinovich, Dmitry

    We demonstrate saturable absorber behavior of n-type semiconductors in the THz frequency range using nonlinear THz spectroscopy. Further, we observe THz pulse shortening and increase of the group refractive index at high field strengths....

  4. Taming electromagnetic metamaterials for isotropic perfect absorbers

    Doan Tung Anh


    Full Text Available Conventional metamaterial absorbers, which consist of a dielectric spacer sandwiched between metamaterial resonators and a metallic ground plane, have been inherently anisotropic. In this paper, we present an alternative approach for isotropic perfect absorbers using symmetric metamaterial structures. We show that by systematically manipulating the electrically and magnetically induced losses, one can achieve a desired absorption without breaking the structural homogeneity. Finite integration simulations and standard retrieval method are performed to elaborate on our idea.

  5. Absorbing Boundary Conditions for Hyperbolic Systems

    Matthias Ehrhardt


    This paper deals with absorbing boundary conditions for hyperbolic systems in one and two space dimensions. We prove the strict well-posedness of the resulting initial boundary value problem in 1D. Afterwards we establish the GKS-stability of the corresponding Lax-Wendroff-type finite difference scheme. Hereby, we have to extend the classical proofs, since the (discretized) absorbing boundary conditions do not fit the standard form of boundary conditions for hyperbolic systems.

  6. Graphene and Graphene Metamaterials for Terahertz Absorbers

    Andryieuski, Andrei; Pizzocchero, Filippo; Booth, Tim; Bøggild, Peter


    Graphene, due to the possibility to tune its conductivity, is the promising material for a range of the terahertz (THz) applications, such as tunable reflectors, absorbers, modulators, filters and polarization converters. Subwavelength structuring of graphene in order to form metamaterials allows for even more control over the THz waves. In this poster presentation I will show an elegant way to describe the graphene metamaterials and the design of graphene based absorbers. I will also present...

  7. Perfect terahertz absorber using fishnet based metafilm

    Azad, Abul Kalam [Los Alamos National Laboratory; Shchegolkov, Dmitry Yu [Los Alamos National Laboratory; Chen, Houtong [Los Alamos National Laboratory; Taylor, Antoinette [Los Alamos National Laboratory; Smirnova, E I [Los Alamos National Laboratory; O' Hara, John F [Los Alamos National Laboratory


    We present a perfect terahertz (THz) absorber working for a broad-angle of incidence. The two fold symmetry of rectangular fishnet structure allows either complete absorption or mirror like reflection depending on the polarization of incident the THz beam. Metamaterials enable the ability to control the electromagnetic wave in a unique fashion by designing the permittivity or permeability of composite materials with desired values. Although the initial idea of metamaterials was to obtain a negative index medium, however, the evolution of metamaterials (MMs) offers a variety of practically applicable devices for controlling electromagnetic wave such as tunable filters, modulators, phase shifters, compact antenna, absorbers, etc. Terahertz regime, a crucial domain of the electromagnetic wave, is suffering from the scarcity of the efficient devices and might take the advantage of metamaterials. Here, we demonstrate design, fabrication, and characterization of a terahertz absorber based on a simple fishnet metallic film separated from a ground mirror plane by a dielectric spacer. Such absorbers are in particular important for bolometric terahertz detectors, high sensitivity imaging, and terahertz anechoic chambers. Recently, split-ring-resonators (SRR) have been employed for metamaterial-based absorbers at microwave and THz frequencies. The experimental demonstration reveals that such absorbers have absorptivity close to unity at resonance frequencies. However, the downside of these designs is that they all employ resonators of rather complicated shape with many fine parts and so they are not easy to fabricate and are sensitive to distortions.

  8. Advances in micro-perforated panel absorbers

    LIU Ke; TIAN Jing; JIAO Fenglei; L(U) Yadong


    Theoretical and experimental investigations on the performance of micro-perforated-panel absorbers are reviewed in this paper. By reviewing recent research work, this paper reveals a relationship between the maximum absorption coefficient and the limit of the absorption frequency bandwidth. It has been demonstrated that the absorption frequency bandwidth can be extended up to 3 or 4 octaves as the diameters of the micro-holes decrease. This has become possible with the development of the technologies for manufacturing micro-perforated panels,such as laser drilling, powder metallurgy, welded meshing and electro-etching to form micrometer order holes. In this paper, absorption characteristics of such absorbers in random fields and in high sound intensity are discussed both theoretically and experimentally. A new absorbing structure based on micro-perforated-panel absorbers demonstrate experimentally high sound absorption capability. This review shows that the micro-perforated-panel absorber has potentials to be one of ideal absorbing materials in the 21st century.

  9. Adaptive Piezoelectric Absorber for Active Vibration Control

    Sven Herold


    Full Text Available Passive vibration control solutions are often limited to working reliably at one design point. Especially applied to lightweight structures, which tend to have unwanted vibration, active vibration control approaches can outperform passive solutions. To generate dynamic forces in a narrow frequency band, passive single-degree-of-freedom oscillators are frequently used as vibration absorbers and neutralizers. In order to respond to changes in system properties and/or the frequency of excitation forces, in this work, adaptive vibration compensation by a tunable piezoelectric vibration absorber is investigated. A special design containing piezoelectric stack actuators is used to cover a large tuning range for the natural frequency of the adaptive vibration absorber, while also the utilization as an active dynamic inertial mass actuator for active control concepts is possible, which can help to implement a broadband vibration control system. An analytical model is set up to derive general design rules for the system. An absorber prototype is set up and validated experimentally for both use cases of an adaptive vibration absorber and inertial mass actuator. Finally, the adaptive vibration control system is installed and tested with a basic truss structure in the laboratory, using both the possibility to adjust the properties of the absorber and active control.

  10. Development of a primary standard for absorbed dose from unsealed radionuclide solutions

    Billas, I.; Shipley, D.; Galer, S.; Bass, G.; Sander, T.; Fenwick, A.; Smyth, V.


    Currently, the determination of the internal absorbed dose to tissue from an administered radionuclide solution relies on Monte Carlo (MC) calculations based on published nuclear decay data, such as emission probabilities and energies. In order to validate these methods with measurements, it is necessary to achieve the required traceability of the internal absorbed dose measurements of a radionuclide solution to a primary standard of absorbed dose. The purpose of this work was to develop a suitable primary standard. A comparison between measurements and calculations of absorbed dose allows the validation of the internal radiation dose assessment methods. The absorbed dose from an yttrium-90 chloride (90YCl) solution was measured with an extrapolation chamber. A phantom was developed at the National Physical Laboratory (NPL), the UK’s National Measurement Institute, to position the extrapolation chamber as closely as possible to the surface of the solution. The performance of the extrapolation chamber was characterised and a full uncertainty budget for the absorbed dose determination was obtained. Absorbed dose to air in the collecting volume of the chamber was converted to absorbed dose at the centre of the radionuclide solution by applying a MC calculated correction factor. This allowed a direct comparison of the analytically calculated and experimentally determined absorbed dose of an 90YCl solution. The relative standard uncertainty in the measurement of absorbed dose at the centre of an 90YCl solution with the extrapolation chamber was found to be 1.6% (k  =  1). The calculated 90Y absorbed doses from published medical internal radiation dose (MIRD) and radiation dose assessment resource (RADAR) data agreed with measurements to within 1.5% and 1.4%, respectively. This study has shown that it is feasible to use an extrapolation chamber for performing primary standard absorbed dose measurements of an unsealed radionuclide solution. Internal radiation

  11. Warm Absorber Diagnostics of AGN Dynamics

    Kallman, Timothy

    Warm absorbers and related phenomena are observable manifestations of outflows or winds from active galactic nuclei (AGN) that have great potential value. Understanding AGN outflows is important for explaining the mass budgets of the central accreting black hole, and also for understanding feedback and the apparent co-evolution of black holes and their host galaxies. In the X-ray band warm absorbers are observed as photoelectric absorption and resonance line scattering features in the 0.5-10 keV energy band; the UV band also shows resonance line absorption. Warm absorbers are common in low luminosity AGN and they have been extensively studied observationally. They may play an important role in AGN feedback, regulating the net accretion onto the black hole and providing mechanical energy to the surroundings. However, fundamental properties of the warm absorbers are not known: What is the mechanism which drives the outflow?; what is the gas density in the flow and the geometrical distribution of the outflow?; what is the explanation for the apparent relation between warm absorbers and the surprising quasi-relativistic 'ultrafast outflows' (UFOs)? We propose a focused set of model calculations that are aimed at synthesizing observable properties of warm absorber flows and associated quantities. These will be used to explore various scenarios for warm absorber dynamics in order to answer the questions in the previous paragraph. The guiding principle will be to examine as wide a range as possible of warm absorber driving mechanisms, geometry and other properties, but with as careful consideration as possible to physical consistency. We will build on our previous work, which was a systematic campaign for testing important class of scenarios for driving the outflows. We have developed a set of tools that are unique and well suited for dynamical calculations including radiation in this context. We also have state-of-the-art tools for generating synthetic spectra, which are

  12. Ultrathin flexible dual band terahertz absorber

    Shan, Yan; Chen, Lin; Shi, Cheng; Cheng, Zhaoxiang; Zang, Xiaofei; Xu, Boqing; Zhu, Yiming


    We propose an ultrathin and flexible dual band absorber operated at terahertz frequencies based on metamaterial. The metamaterial structure consists of periodical split ring resonators with two asymmetric gaps and a metallic ground plane, separated by a thin-flexible dielectric spacer. Particularly, the dielectric spacer is a free-standing polyimide film with thickness of 25 μm, resulting in highly flexible for our absorber and making it promising for non-planar applications such as micro-bolometers and stealth aircraft. Experimental results show that the absorber has two resonant absorption frequencies (0.41 THz and 0.75 THz) with absorption rates 92.2% and 97.4%, respectively. The resonances at the absorption frequencies come from normal dipole resonance and high-order dipole resonance which is inaccessible in the symmetrical structure. Multiple reflection interference theory is used to analyze the mechanism of the absorber and the results are in good agreement with simulated and experimental results. Furthermore, the absorption properties are studied under various spacer thicknesses. This kind of metamaterial absorber is insensitive to polarization, has high absorption rates (over 90%) with wide incident angles range from 0° to 45° and the absorption rates are also above 90% when wrapping it to a curved surface.

  13. Oxygen absorbers in food preservation: a review.

    Cichello, Simon Angelo


    The preservation of packaged food against oxidative degradation is essential to establish and improve food shelf life, customer acceptability, and increase food security. Oxygen absorbers have an important role in the removal of dissolved oxygen, preserving the colour, texture and aroma of different food products, and importantly inhibition of food spoilage microbes. Active packaging technology in food preservation has improved over decades mostly due to the sealing of foods in oxygen impermeable package material and the quality of oxygen absorber. Ferrous iron oxides are the most reliable and commonly used oxygen absorbers within the food industry. Oxygen absorbers have been transformed from sachets of dried iron-powder to simple self-adhesive patches to accommodate any custom size, capacity and application. Oxygen concentration can be effectively lowered to 100 ppm, with applications spanning a wide range of food products and beverages across the world (i.e. bread, meat, fish, fruit, and cheese). Newer molecules that preserve packaged food materials from all forms of degradation are being developed, however oxygen absorbers remain a staple product for the preservation of food and pharmaceutical products to reduce food wastage in developed nations and increased food security in the developing & third world.

  14. Detecting and interpreting statistical lensing by absorbers

    Ménard, B


    We propose a method for detecting gravitational magnification of distant sources, like quasars, due to absorber systems detected in their spectra. We first motivate the use of metal absorption lines rather than Lyman-alpha lines, then we show how to relate the observed moments of the source magnitude distribution to the mass distribution of absorbers. In order to illustrate the feasibility of the method, we use a simple model to estimate the amplitude of the effect expected for MgII absorption lines, and show that their lensing signal might already be detectable in large surveys like the SDSS. Our model suggests that quasars behind strong MgII absorbers are in average brightened by -0.05 to -0.2 magnitude due to magnification. One must therefore revisit the claim that, in magnitude limited surveys, quasars with strong absorbers tend to be missed due to extinction effects. In addition to constraining the mass of absorber systems, applying our method will allow for the quantification of this bias.

  15. Distributed Absorber for Noise and Vibration Control

    Michel Azoulay


    Full Text Available An approach to a wide-band frequency passive vibration attenuation is introduced in this paper. This aims to suppress noise and vibration of extended multimode objects like plates, panels and shells. The absorber is arranged in the form of a single-layer assembly of small inertial bodies (balls being distributed and moulded within the light visco-elastic media (e.g. silicone resin. The absorber as a whole is embedded into object face covering the critical patches of the system surface. For the purpose of characterization, the authors introduced the complex frequency response function relating the volume velocity produced by the vibrating object surface (response stimulated by a point-wise force (stimulus applied to a particular point. The simulation and optimization of the main frequency characteristics has been performed using a full scale 3-dimensional Finite Element model. These revealed some new dynamic features of absorber's structures, which can contribute to vibration attenuation. A full-scale physical experimentation with synthesised absorber's structures confirmed the main results of simulation and has shown significant noise reduction over a staggering 0–20 kHz frequency band. This was achieved with a negligible weight and volume penalty due to the addition of the absorber. The results can find multiple applications in noise and vibration control of different structures. Some examples of such applications are presented.

  16. A Design Outline for Floating Point Absorber Wave Energy Converters

    Mohammed Faizal


    Full Text Available An overview of the most important development stages of floating point absorber wave energy converters is presented. At a given location, the wave energy resource has to be first assessed for varying seasons. The mechanisms used to convert wave energy to usable energy vary for different wave energy conversion systems. The power output of the generator will have variations due to varying incident waves. The wave structure-interaction leads to modifications in the incident waves; thus, the power output is also affected. The device has to be stable enough to prevent itself from capsizing. The point absorber will give optimum performance when the incident wave frequencies correspond to the natural frequency of the device. The methods for calculating natural frequencies for pitching and heaving systems are presented. Mooring systems maintain the point absorber at the desired location. Various mooring configurations as well as the most commonly used materials for mooring lines are discussed. An overview of scaled modelling is also presented.

  17. Absorbing material based on starch having improved absorbent properties and process for the preparation thereof

    Feil, H.; Soest, van J.J.G.; Schijndel, van R.J.G.


    A biodegradable, highly water-absorbing polymer based on starch or derivatives thereof is described, wherein the starch has not been chemically modified or only to a degree of substitution below 0.2, and has a water-absorbing power of at least 10 times its own weight, half of the water absorption be

  18. Non-Absorbable Gas Behavior in the Absorber/Evaporator of a Absorption Chiller

    Suzuki, Hiroshi; Nagamoto, Wataru; Sugiyama, Takahide

    A two-dimensional numerical study on non-absorbable gas behavior in the absorber/evaporator of an absorption chiller has been performed. In the present study, the effect of the pitch-to-diameter ratio of a cylinder bundle in the absorber was highlighted. From the results, a sudden decrease of the overall heat transfer coefficient of the absorber was observed at a certain mean concentration of non-absorbable gas for each pitch-to-diameter ratio. Such a critical concentration was also found to decrease as the pitch-to- diameter ratio increased. The sudden decrease occurs due to the sudden disappearance of recirculating region, which is formed between the absorber and the evaporator, and where most of non-absorbable gas stays when it exists. As the pitch-to-diameter ratio increases, the recirculating region becomes weak because the velocity of the high velocity region supporting the recirculating flow decreases. Then, the critical mean concentration of non-absorbable gas is found to decrease as pitch-to-ratio increases.

  19. Neutron absorbed dose in a pacemaker CMOS

    Borja H, C. G.; Guzman G, K. A.; Valero L, C.; Banuelos F, A.; Hernandez D, V. M.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Paredes G, L., E-mail: [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)


    The neutron spectrum and the absorbed dose in a Complementary Metal Oxide Semiconductor (CMOS), has been estimated using Monte Carlo methods. Eventually a person with a pacemaker becomes an oncology patient that must be treated in a linear accelerator. Pacemaker has integrated circuits as CMOS that are sensitive to intense and pulsed radiation fields. Above 7 MV therapeutic beam is contaminated with photoneutrons that could damage the CMOS. Here, the neutron spectrum and the absorbed dose in a CMOS cell was calculated, also the spectra were calculated in two point-like detectors in the room. Neutron spectrum in the CMOS cell shows a small peak between 0.1 to 1 MeV and a larger peak in the thermal region, joined by epithermal neutrons, same features were observed in the point-like detectors. The absorbed dose in the CMOS was 1.522 x 10{sup -17} Gy per neutron emitted by the source. (Author)

  20. Distributed electric absorbers of beam vibrations

    dell'lsola, Francesco; Del Vescovo, Dionisio; Maurini, Corrado


    Several electric vibration absorbers based on distributed piezoelectric control of beam vibrations are studied. The damping devices are conceived by interconnecting with different modular electric networks an array of piezoelectric transducers uniformly distributed on a beam. Five different vibration absorbers made of five different network interconnecting topologies are considered and their damping performances are analyzed and compared. The analysis is based on homogenized models of modular piezo-electromechanical systems. The optimal parameters of these absorbers are found by adopting the criterion of critical damping of waves with a single wave number. We show that: i) there is an interconnecting network providing an optimal multimodal damping; ii) the performances required to the electr(on)ic components can be significantly decreased by increasing the number (and decreasing the dimensions) of the piezoelectric transducers.

  1. On the warm absorber in AGN outflow

    Adhikari, T P; Sobolewska, M; Czerny, B


    Warm absorber (WA) is an ionised gas present in the line of sight to the AGN central engine. The effect of the absorber is imprinted in the absorption lines observed in X-ray spectra of AGN. In this work, we model the WA in Seyfert 1 galaxy Mrk 509 using its recently published shape of broad band spectral energy distribution (SED) as a continuum illuminating the absorber. Using the photoionization code {\\sc Titan}, recently we have shown that the absorption measure distribution (AMD) found for this object can be successfully modelled as a single slab of gas in total pressure (radiation+gas) equilibrium, contrary to the usual models of constant density multiple slabs. We discuss the transmitted spectrum that would be recorded by an observer after the radiation from the nucleus passes through the WA.

  2. Ferrite HOM Absorber for the RHIC ERL

    Hahn,H.; Choi, E.M.; Hammons, L.


    A superconducting Energy Recovery Linac is under construction at Brookhaven National Laboratory to serve as test bed for RHIC upgrades. The damping of higher-order modes in the superconducting five-cell cavity for the Energy-Recovery linac at RHIC is performed exclusively by two ferrite absorbers. The ferrite properties have been measured in ferrite-loaded pill box cavities resulting in the permeability values given by a first-order Debye model for the tiled absorber structure and an equivalent permeability value for computer simulations with solid ring dampers. Measured and simulated results for the higher-order modes in the prototype copper cavity are discussed. First room-temperature measurements of the finished niobium cavity are presented which confirm the effective damping of higher-order modes in the ERL. by the ferrite absorbers.

  3. Broadband plasmonic absorber for photonic integrated circuits

    Xiong, Xiao; Ren, Xi-Feng; Guo, Guang-Can


    The loss of surface plasmon polaritons has long been considered as a fatal shortcoming in information transport. Here we propose a plasmonic absorber utilizing this "shortcoming" to absorb the stray light in photonic integrated circuits (PICs). Based on adiabatic mode evolution, its performance is insensitive to incident wavelength with bandwidth larger than 300nm, and robust against surrounding environment and temperature. Besides, the use of metal enables it to be very compact and beneficial to thermal dissipation. With this 40um-long absorber, the absorption efficiency can be over 99.8% at 1550nm, with both the reflectivity and transmittance of incident light reduced to less than 0.1%. Such device may find various applications in PICs, to eliminate the residual strong pump laser or stray light.

  4. Interference theory of metamaterial perfect absorbers

    Chen, Hou-Tong


    The impedance matching in metamaterial perfect absorbers has been believed to involve and rely on magnetic resonant response, with a direct evidence from the anti-parallel directions of surface currents in the metal structures. Here we present a different theoretical interpretation based on interferences, which shows that the two layers of metal structure in metamaterial absorbers are linked only by multiple reflections with negligible near-field interactions or magnetic resonances. This is further supported by the out-of-phase surface currents derived at the interfaces of resonator array and ground plane through multiple reflections and superpositions. The theory developed here explains all features observed in narrowband metamaterial absorbers and therefore provides a profound understanding of the underlying physics.

  5. Absorber Materials at Room and Cryogenic Temperatures

    F. Marhauser, T.S. Elliott, A.T. Wu, E.P. Chojnacki, E. Savrun


    We recently reported on investigations of RF absorber materials at cryogenic temperatures conducted at Jefferson Laboratory (JLab). The work was initiated to find a replacement material for the 2 Kelvin low power waveguide Higher Order Mode (HOM) absorbers employed within the original cavity cryomodules of the Continuous Electron Beam Accelerator Facility (CEBAF). This effort eventually led to suitable candidates as reported in this paper. Furthermore, though constrained by small funds for labor and resources, we have analyzed a variety of lossy ceramic materials, several of which could be usable as HOM absorbers for both normal conducting and superconducting RF structures, e.g. as loads in cavity waveguides and beam tubes either at room or cryogenic temperatures and, depending on cooling measures, low to high operational power levels.

  6. Precise dispersion equations of absorbing filter glasses

    Reichel, S.; Biertümpfel, Ralf


    The refractive indices versus wavelength of optical transparent glasses are measured at a few wavelengths only. In order to calculate the refractive index at any wavelength, a so-called Sellmeier series is used as an approximation of the wavelength dependent refractive index. Such a Sellmeier representation assumes an absorbing free (= loss less) material. In optical transparent glasses this assumption is valid since the absorption of such transparent glasses is very low. However, optical filter glasses have often a rather high absorbance in certain regions of the spectrum. The exact description of the wavelength dependent function of the refractive index is essential for an optimized design for sophisticated optical applications. Digital cameras use an IR cut filter to ensure good color rendition and image quality. In order to reduce ghost images by reflections and to be nearly angle independent absorbing filter glass is used, e.g. blue glass BG60 from SCHOTT. Nowadays digital cameras improve their performance and so the IR cut filter needs to be improved and thus the accurate knowledge of the refractive index (dispersion) of the used glasses must be known. But absorbing filter glass is not loss less as needed for a Sellmeier representation. In addition it is very difficult to measure it in the absorption region of the filter glass. We have focused a lot of effort on measuring the refractive index at specific wavelength for absorbing filter glass - even in the absorption region. It will be described how to do such a measurement. In addition we estimate the use of a Sellmeier representation for filter glasses. It turns out that in most cases a Sellmeier representation can be used even for absorbing filter glasses. Finally Sellmeier coefficients for the approximation of the refractive index will be given for different filter glasses.

  7. Durability of Polymeric Glazing and Absorber Materials

    Jorgensen, G.; Terwilliger, K.; Bingham, C.; Lindquist, C.; Milbourne, M.


    The Solar Heating and Lighting Program has set the goal of reducing the cost of solar water heating systems by at least 50%. An attractive approach to such large cost reduction is to replace glass and metal parts with less-expensive, lighter-weight, more-integrated polymeric components. The key challenge with polymers is to maintain performance and assure requisite durability for extended lifetimes. We have begun evaluation of several new UV-screened polycarbonate sheet glazing constructions. This has involved interactions with several major polymer industry companies to obtain improved candidate samples. Proposed absorber materials were tested for UV resistance, and appear adequate for unglazed ICS absorbers.

  8. Timing the warm absorber in NGC 4051

    Silva, C. V.; Uttley, P.; Costantini, E.


    We investigated, using spectral-timing analysis, the characterization of highly ionized outflows in Seyfert galaxies, the so-called warm absorbers. Here, we present our results of the extensive 600 ks of XMM-Newton archival observations of the bright and highly variable Seyfert 1 galaxy NGC 4051 whose spectrum has revealed a complex multicomponent wind. Making use of both RGS and EPIC-pn data, we performed a detailed analysis through a time-dependent photoionization code in combination with spectral and Fourier spectral-timing techniques. The source light curves and the warm absorber parameters obtained from the data were used to simulate the response of the gas to variations in the ionizing flux of the central source. The resulting time variable spectra were employed to predict the effects of the warm absorber on the time lags and coherence of the energy dependent light curves. We have found that, in the absence of any other lag mechanisms, a warm absorber with the characteristics of the one observed in NGC 4051, is able to produce soft lags, up to 100 s, on timescales of hours. The time delay is associated with the response of the gas to changes in the ionizing source, either by photoionization or radiative recombination, which is dependent on its density. The range of radial distances that, under our assumptions, yield longer time delays are distances r 0.3-1.0 × 1016 cm, and hence gas densities n 0.4-3.0 × 107 cm-3. Since these ranges are comparable to the existing estimates of the location of the warm absorber in NGC 4051, we suggest that it is likely that the observed X-ray time lags may carry a signature of the warm absorber response time to changes in the ionizing continuum. Our results show that the warm absorber in NGC 4051 does not introduce lags on the short timescales associated with reverberation, but will likely modify the hard continuum lags seen on longer timescales, which in this source have been measured to be on the order of 50 s. Hence, these

  9. Shock-Absorbent Ball-Screw Mechanism

    Hirr, Otto A., Jr.; Meneely, R. W.


    Actuator containing two ball screws in series employs Belleville springs to reduce impact loads, thereby increasing life expectancy. New application of springs increases reliability of equipment in which ball screws commonly used. Set of three springs within lower screw of ball-screw mechanism absorbs impacts that result when parts reach their upper and lower limits of movement. Mechanism designed with Belleville springs as shock-absorbing elements because springs have good energy-to-volume ratio and easily stacked to attain any stiffness and travel.

  10. Spin Particle in an Absorbing Environment

    Amooshahi, M.


    The quantum dynamics of a localized spin Particle interacting with an absorbing environment is investigated. The quantum Langevin-Schrödinger equation for spin is obtained. The susceptibility function of the environment is calculated in terms of the coupling function of the spin and the environment. it is shown that the susceptibility function satisfies the Kramers-Kronig relations. Spontaneous emission and the shift frequency of the spin is obtained in terms of the imaginary part of the susceptibility function in frequency domain. Some transition probabilities between the spin states are calculated when the absorbing environment is in the thermal state.

  11. Quantum walk with one variable absorbing boundary

    Wang, Feiran; Zhang, Pei; Wang, Yunlong; Liu, Ruifeng; Gao, Hong; Li, Fuli


    Quantum walks constitute a promising ingredient in the research on quantum algorithms; consequently, exploring different types of quantum walks is of great significance for quantum information and quantum computation. In this study, we investigate the progress of quantum walks with a variable absorbing boundary and provide an analytical solution for the escape probability (the probability of a walker that is not absorbed by the boundary). We simulate the behavior of escape probability under different conditions, including the reflection coefficient, boundary location, and initial state. Moreover, it is also meaningful to extend our research to the situation of continuous-time and high-dimensional quantum walks.

  12. 21 CFR 880.6025 - Absorbent tipped applicator.


    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Absorbent tipped applicator. 880.6025 Section 880... Devices § 880.6025 Absorbent tipped applicator. (a) Identification. An absorbent tipped applicator is a device intended for medical purposes that consists of an absorbent swab on a wooden, paper, or...

  13. 21 CFR 880.5300 - Medical absorbent fiber.


    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Medical absorbent fiber. 880.5300 Section 880.5300... Devices § 880.5300 Medical absorbent fiber. (a) Identification. A medical absorbent fiber is a device...'s body surface. Absorbent fibers intended solely for cosmetic purposes are not included in...

  14. Mechanical and microwave absorbing properties of carbon-filled polyurethane.

    Kucerová, Z; Zajícková, L; Bursíková, V; Kudrle, V; Eliás, M; Jasek, O; Synek, P; Matejková, J; Bursík, J


    Polyurethane (PU) matrix composites were prepared with various carbon fillers at different filler contents in order to investigate their structure, mechanical and microwave absorbing properties. As fillers, flat carbon microparticles, carbon microfibers and multiwalled carbon nanotubes (MWNT) were used. The microstructure of the composite was examined by scanning electron microscopy and transmission electron microscopy. Mechanical properties, namely universal hardness, plastic hardness, elastic modulus and creep were assessed by means of depth sensing indentation test. Mechanical properties of PU composite filled with different fillers were investigated and the composite always exhibited higher hardness, elastic modulus and creep resistance than un-filled PU. Influence of filler shape, content and dispersion was also investigated.

  15. Tunable metamaterial dual-band terahertz absorber

    Luo, C. Y.; Li, Z. Z.; Guo, Z. H.; Yue, J.; Luo, Q.; Yao, G.; Ji, J.; Rao, Y. K.; Li, R. K.; Li, D.; Wang, H. X.; Yao, J. Q.; Ling, F. R.


    We report a design of a temperature controlled tunable dual band terahertz absorber. The compact single unit cell consists of two nested closed square ring resonators and a layer metallic separated by a substrate strontium titanate (STO) dielectric layer. It is found that the absorber has two distinctive absorption peaks at frequencies 0.096 THz and 0.137 THz, whose peaks are attained 97% and 75%. Cooling the absorber from 400 K to 250 K causes about 25% and 27% shift compared to the resonance frequency of room temperature, when we cooling the temperature to 150 K, we could attained both the two tunabilities exceeding 53%. The frequency tunability is owing to the variation of the dielectric constant of the low-temperature co-fired ceramic (LTCC) substrate. The mechanism of the dual band absorber is attributed to the overlapping of dual resonance frequencies, and could be demonstrated by the distributions of the electric field. The method opens up avenues for designing tunable terahertz devices in detection, imaging, and stealth technology.

  16. Review of Plasmonic Nanocomposite Metamaterial Absorber

    Mehdi Keshavarz Hedayati


    Full Text Available Plasmonic metamaterials are artificial materials typically composed of noble metals in which the features of photonics and electronics are linked by coupling photons to conduction electrons of metal (known as surface plasmon. These rationally designed structures have spurred interest noticeably since they demonstrate some fascinating properties which are unattainable with naturally occurring materials. Complete absorption of light is one of the recent exotic properties of plasmonic metamaterials which has broadened its application area considerably. This is realized by designing a medium whose impedance matches that of free space while being opaque. If such a medium is filled with some lossy medium, the resulting structure can absorb light totally in a sharp or broad frequency range. Although several types of metamaterials perfect absorber have been demonstrated so far, in the current paper we overview (and focus on perfect absorbers based on nanocomposites where the total thickness is a few tens of nanometer and the absorption band is broad, tunable and insensitive to the angle of incidence. The nanocomposites consist of metal nanoparticles embedded in a dielectric matrix with a high filling factor close to the percolation threshold. The filling factor can be tailored by the vapor phase co-deposition of the metallic and dielectric components. In addition, novel wet chemical approaches are discussed which are bio-inspired or involve synthesis within levitating Leidenfrost drops, for instance. Moreover, theoretical considerations, optical properties, and potential application of perfect absorbers will be presented.

  17. Microstructured extremely thin absorber solar cells

    Biancardo, Matteo; Krebs, Frederik C


    In this paper we present the realization of extremely thin absorber (ETA) solar cells employing conductive glass substrates functionalized with TiO2 microstructures produced by embossing. Nanocrystalline or compact TiO2 films on Indium doped tin oxide (ITO) glass substrates were embossed...

  18. Methods of calculating radiation absorbed dose.

    Wegst, A V


    The new tumoricidal radioactive agents being developed will require a careful estimate of radiation absorbed tumor and critical organ dose for each patient. Clinical methods will need to be developed using standard imaging or counting instruments to determine cumulated organ activities with tracer amounts before the therapeutic administration of the material. Standard MIRD dosimetry methods can then be applied.

  19. Can polar bear hairs absorb environmental energy?

    He Ji-Huan


    Full Text Available A polar bear (Ursus maritimus has superior ability to survive in harsh Arctic regions, why does the animal have such an excellent thermal protection? The present paper finds that the unique labyrinth cavity structure of the polar bear hair plays an important role. The hair can not only prevent body temperature loss but can also absorb energy from the environment.

  20. Timing the warm absorber in NGC 4051

    Silva, Catia; Costantini, Elisa


    We investigated, using spectral-timing analysis, the characterization of highly ionized outflows in Seyfert galaxies, the so-called warm absorbers. Here, we present our results on the extensive ~ 600 ks of XMM-Newton archival observations of the bright and highly variable Seyfert 1 galaxy NGC 4051, whose spectrum has revealed a complex multicomponent wind. Making use of both RGS and EPIC-pn data, we performed a detailed analysis through a time-dependent photoionization code in combination with spectral and Fourier spectral-timing techniques. The source light curves and the warm absorber parameters obtained from the data were used to simulate the response of the gas due to variations in the ionizing flux of the central source. The resulting time variable spectra were employed to predict the effects of the warm absorber on the time lags and coherence of the energy dependent light curves. We have found that, in the absence of any other lag mechanisms, a warm absorber with the characteristics of the one observed ...

  1. Can polar bear hairs absorb environmental energy?

    He Ji-Huan; Wang Qing-Li; Sun Jie


    A polar bear (Ursus maritimus) has superior ability to survive in harsh Arctic regions, why does the animal have such an excellent thermal protection? The present paper finds that the unique labyrinth cavity structure of the polar bear hair plays an important role. The hair can not only prevent body temperature loss but can also absorb energy from the environment.

  2. Fabrication of high efficacy selective solar absorbers

    Tile, N


    Full Text Available High efficiency tandem selective solar absorber materials of carbon in nickel oxide (C-NiO) composite were fabricated on an aluminium substrate using a simple and cost effective sol-gel process. The process involved preparation of carbon and nickel...

  3. Moving core beam energy absorber and converter

    Degtiarenko, Pavel V.


    A method and apparatus for the prevention of overheating of laser or particle beam impact zones through the use of a moving-in-the-coolant-flow arrangement for the energy absorbing core of the device. Moving of the core spreads the energy deposition in it in 1, 2, or 3 dimensions, thus increasing the effective cooling area of the device.

  4. Semiconductor saturable absorbers for ultrafast terahertz signals

    Hoffmann, Matthias C.; Turchinovich, Dmitry


    We demonstrate saturable absorber behavior of n-type semiconductors GaAs, GaP, and Ge in the terahertz THz frequency range at room temperature using nonlinear THz spectroscopy. The saturation mechanism is based on a decrease in electron conductivity of semiconductors at high electron momentum sta...

  5. Absorbed fractions for electrons in ellipsoidal volumes

    Amato, E.; Lizio, D.; Baldari, S.


    We applied a Monte Carlo simulation in Geant4 in order to calculate the absorbed fractions for monoenergetic electrons in the energy interval between 10 keV and 2 MeV, uniformly distributed in ellipsoids made from soft tissue. For each volume, we simulated a spherical shape, four oblate and four prolate ellipsoids, and one scalene shape. For each energy and for every geometrical configuration, an analytical relationship between the absorbed fraction and a 'generalized radius' was found, and the dependence of the fit parameters from electron energy is discussed and fitted by proper parametric functions. With the proposed formulation, the absorbed fraction for electrons in the 10-2000 keV energy range can be calculated for all volumes and for every ellipsoidal shape of practical interest. This method can be directly applied to evaluation of the absorbed fraction from the radionuclide emission of monoenergetic electrons, such as Auger or conversion electrons. The average deposited energy per disintegration in the case of extended beta spectra can be evaluated through integration. Two examples of application to a pure beta emitter such as 90Y and to 131I, whose emission include monoenergetic and beta electrons plus gamma photons, are presented. This approach represent a generalization of our previous studies, allowing a comprehensive treatment of absorbed fractions from electron and photon sources uniformly distributed in ellipsoidal volumes of any ellipticity and volume, in the whole range of practical interest for internal dosimetry in nuclear medicine applications, as well as in radiological protection estimations of doses from an internal contamination.

  6. Neutron absorbers and methods of forming at least a portion of a neutron absorber

    Guillen, Donna P; Porter, Douglas L; Swank, W David; Erickson, Arnold W


    Methods of forming at least a portion of a neutron absorber include combining a first material and a second material to form a compound, reducing the compound into a plurality of particles, mixing the plurality of particles with a third material, and pressing the mixture of the plurality of particles and the third material. One or more components of neutron absorbers may be formed by such methods. Neutron absorbers may include a composite material including an intermetallic compound comprising hafnium aluminide and a matrix material comprising pure aluminum.

  7. Economic Impact of the Use of an Absorbable Adhesion Barrier in Preventing Adhesions Following Open Gynecologic Surgeries.

    Roy, Sanjoy; Carlton, Rashad; Weisberg, Martin; Clark, Ryan; Migliaccio-Walle, Kristen; Chapa, Hector


    We used an economic model to assess the impact of using the GYNECARE INTERCEED absorbable adhesion barrier for reducing the incidence of postoperative adhesions in open surgical gynecologic procedures. Caesarean section surgery, hysterectomy, myomectomy, ovarian surgery, tubal surgery, and endometriosis surgery were modeled with and without the use of GYNECARE INTERCEED absorbable adhesion barrier. Incremental GYNECARE INTERCEED absorbable adhesion barrier material costs, medical costs arising from complications, and adhesion-related readmissions were considered. GYNECARE INTERCEED absorbable adhesion barrier use was assumed in 75% of all procedures. The economic impact was reported during a 3-year period from a United States hospital perspective. Assuming 100 gynecologic surgeries of each type and an average of one GYNECARE INTERCEED absorbable adhesion barrier sheet per surgery, a net savings of $540,823 with GYNECARE INTERCEED absorbable adhesion barrier during 3 years is estimated. In addition, GYNECARE INTERCEED absorbable adhesion barrier use resulted in 62 fewer cases of patients developing adhesions. Although the use of GYNECARE INTERCEED absorbable adhesion barrier added $137,250 in material costs, this was completely offset by the reduction in length of stay ($178,766 savings), fewer adhesion-related readmissions ($458,220 savings), and operating room cost ($41,078 savings). Adoption of the GYNECARE INTERCEED absorbable adhesion barrier for appropriate gynecologic surgeries would likely result in significant savings for hospitals, driven primarily by clinical patient benefits in terms of decreased length of stay and adhesion-related readmissions.

  8. Effect of the bio-absorbent on the microwave absorption property of the flaky CIPs/rubber absorbers

    Cheng, Yang; Xu, Yonggang, E-mail:; Cai, Jun; Yuan, Liming; Zhang, Deyuan


    Microwave absorbing composites filled with flaky carbonyl iron particles (CIPs) and the bio-absorbent were prepared by using a two-roll mixer and a vulcanizing machine. The electromagnetic (EM) parameters were measured by a vector network analyzer and the reflection loss (RL) was measured by the arch method in the frequency range of 1–4 GHz. The uniform dispersion of the absorbents was verified by comparing the calculated RL with the measured one. The results confirm that as the bio-absorbent was added, the permittivity was increased due to the volume content of absorbents, and the permeability was enlarged owing to the volume content of CIPs and interactions between the two absorbents. The composite filled with bio-absorbents achieved an excellent absorption property at a thickness of 1 mm (minimum RL reaches −7.8 dB), and as the RL was less than −10 dB the absorption band was widest (2.1–3.8 GHz) at a thickness of 2 mm. Therefore, the bio-absorbent is a promising additive candidate on fabricating microwave absorbing composites with a thinner thickness and wider absorption band. - Graphical abstract: Morphology of composites filled with flaky CIPs and the bio-absorbent. The enhancement of bio-absorbent on the electromagnetic absorption property of composites filled with flaky carbonyl iron particles (CIPs) is attributed to the interaction of the two absorbents. The volume content of the FCMPs with the larger shape CIPs play an important role in this effects, the composites filled with irons and bio-absorbents can achieve wider-band and thinner-thickness absorbing materials. - Highlights: • Absorbers filled with bio-absorbents and CIPs was fabricated. • Bio-absorbents enhanced the permittivity and permeability of the composites. • The absorbent interactions play a key role in the enhancement mechanism. • Bio-absorbents enhanced the composite RL in 1–4 GHz.

  9. Optimization of sound absorbing performance for gradient multi-layer-assembled sintered fibrous absorbers

    Zhang, Bo; Zhang, Weiyong; Zhu, Jian


    The transfer matrix method, based on plane wave theory, of multi-layer equivalent fluid is employed to evaluate the sound absorbing properties of two-layer-assembled and three-layer-assembled sintered fibrous sheets (generally regarded as a kind of compound absorber or structures). Two objective functions which are more suitable for the optimization of sound absorption properties of multi-layer absorbers within the wider frequency ranges are developed and the optimized results of using two objective functions are also compared with each other. It is found that using the two objective functions, especially the second one, may be more helpful to exert the sound absorbing properties of absorbers at lower frequencies to the best of their abilities. Then the calculation and optimization of sound absorption properties of multi-layer-assembled structures are performed by developing a simulated annealing genetic arithmetic program and using above-mentioned objective functions. Finally, based on the optimization in this work the thoughts of the gradient design over the acoustic parameters- the porosity, the tortuosity, the viscous and thermal characteristic lengths and the thickness of each samples- of porous metals are put forth and thereby some useful design criteria upon the acoustic parameters of each layer of porous fibrous metals are given while applying the multi-layer-assembled compound absorbers in noise control engineering.

  10. A sound absorbing metasurface with coupled resonators

    Li, Junfei; Wang, Wenqi; Xie, Yangbo; Popa, Bogdan-Ioan; Cummer, Steven A.


    An impedance matched surface is able, in principle, to totally absorb the incident sound and yield no reflection, and this is desired in many acoustic applications. Here we demonstrate a design of impedance matched sound absorbing surface with a simple construction. By coupling different resonators and generating a hybrid resonance mode, we designed and fabricated a metasurface that is impedance-matched to airborne sound at tunable frequencies with subwavelength scale unit cells. With careful design of the coupled resonators, over 99% energy absorption at central frequency of 511 Hz with a 50% absorption bandwidth of 140 Hz is achieved experimentally. The proposed design can be easily fabricated, and is mechanically stable. The proposed metasurface can be used in many sound absorption applications such as loudspeaker design and architectural acoustics.

  11. Absorbing angles, Steiner minimal trees, and antipodality

    Martini, Horst; de Wet, P Oloff; 10.1007/s10957-009-9552-1


    We give a new proof that a star $\\{op_i:i=1,...,k\\}$ in a normed plane is a Steiner minimal tree of its vertices $\\{o,p_1,...,p_k\\}$ if and only if all angles formed by the edges at o are absorbing [Swanepoel, Networks \\textbf{36} (2000), 104--113]. The proof is more conceptual and simpler than the original one. We also find a new sufficient condition for higher-dimensional normed spaces to share this characterization. In particular, a star $\\{op_i: i=1,...,k\\}$ in any CL-space is a Steiner minimal tree of its vertices $\\{o,p_1,...,p_k\\}$ if and only if all angles are absorbing, which in turn holds if and only if all distances between the normalizations $\\frac{1}{\\|p_i\\|}p_i$ equal 2. CL-spaces include the mixed $\\ell_1$ and $\\ell_\\infty$ sum of finitely many copies of $R^1$.

  12. Absorbing Software Testing into the Scrum Method

    Tuomikoski, Janne; Tervonen, Ilkka

    In this paper we study, how to absorb software testing into the Scrum method. We conducted the research as an action research during the years 2007-2008 with three iterations. The result showed that testing can and even should be absorbed to the Scrum method. The testing team was merged into the Scrum teams. The teams can now deliver better working software in a shorter time, because testing keeps track of the progress of the development. Also the team spirit is higher, because the Scrum team members are committed to the same goal. The biggest change from test manager’s point of view was the organized Product Owner Team. Test manager don’t have testing team anymore, and in the future all the testing tasks have to be assigned through the Product Backlog.

  13. Use of Wedge Absorbers in MICE

    Neuffer, D. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Summers, D. [Univ. of Mississippi, Oxford, MS (United States); Mohayai, T. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); IIT, Chicago, IL (United States); Snopok, P. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); IIT, Chicago, IL (United States); Rogers, C. [Science and Technology Facilities Council (STFC), Oxford (United Kingdom). Rutherford Appleton Lab. (RAL)


    Wedge absorbers are needed to obtain longitudinal cooling in ionization cooling. They also can be used to obtain emittance exchanges between longitudinal and transverse phase space. There can be large exchanges in emittance, even with single wedges. In the present note we explore the use of wedge absorbers in the MICE experiment to obtain transverse–longitudinal emittance exchanges within present and future operational conditions. The same wedge can be used to explore “direct” and “reverse” emittance exchange dynamics, where direct indicates a configuration that reduces momentum spread and reverse is a configuration that increases momentum spread. Analytical estimated and ICOOL and G4BeamLine simulations of the exchanges at MICE parameters are presented. Large exchanges can be obtained in both reverse and direct configurations.

  14. Liquid neutron absorber alternatives for the MPTRR

    Jatuff, F.E.; Villarino, E.A. [INVAP S.E., S.C. de Bariloche (Argentina)


    The Multi-Purpose Type Research Reactor (MPTRR) control and first shutdown systems consist of six control plates of a Ag-In-Cd alloy. The second shutdown system is given by a liquid neutron absorber, a solution of boric acid, filling the inside of the chimney separating the core from the reflectors. The chimney is composed of four sides (four independent systems), each of them formed by two Zircaloy walls of 0.6 cm, and the empty central space inside (1.8 cm) filled with pure nitrogen during normal operation. The licensing criterion for the second shutdown system (the chimney, for brevity) requires a reactivity worth of {approximately}5000 pcm. The purpose of the work is the analysis of alternative liquid absorbers and the maximum reactivity worth reachable by the second shut-down system.

  15. Oxygen absorbers in food preservation: a review

    Cichello, Simon Angelo


    The preservation of packaged food against oxidative degradation is essential to establish and improve food shelf life, customer acceptability, and increase food security. Oxygen absorbers have an important role in the removal of dissolved oxygen, preserving the colour, texture and aroma of different food products, and importantly inhibition of food spoilage microbes. Active packaging technology in food preservation has improved over decades mostly due to the sealing of foods in oxygen imperme...

  16. 2D Saturable Absorbers for Fibre Lasers

    Robert I. Woodward


    Full Text Available Two-dimensional (2D nanomaterials are an emergent and promising platform for future photonic and optoelectronic applications. Here, we review recent progress demonstrating the application of 2D nanomaterials as versatile, wideband saturable absorbers for Q-switching and mode-locking fibre lasers. We focus specifically on the family of few-layer transition metal dichalcogenides, including MoS2, MoSe2 and WS2.

  17. VUV Absorbing Vapours in n-Perfluorocarbons

    Albrecht, E; Bellunato, T F; Bressan, A; Dalla Torre, S; D'Ambrosio, C; Davenport, M; Dragicevic, M; Duarte-Pinto, S; Fauland, P; Ilie, S; Lenzen, Georg; Pagano, P; Piedigrossi, D; Tessarotto, F; Ullaland, O


    The optical transparency of perfluorocarbons used as Cherenkov media is of prime importance to many Ring Imaging Cherenkov detectors. We will in this paper show that the main photon absorbers in these fluids are hydrocarbons with double or triple bonds. We will moreover discuss a process which can eliminate these pollutants and restore the intrinsic excellent optical transparency of these fluids in the VUV range.

  18. Preparation of perlite-based carbon dioxide absorbent.

    He, H; Wu, L; Zhu, J; Yu, B


    A new highly efficient carbon dioxide absorbent consisting of sodium hydroxide, expanded perlite and acid-base indicator was prepared. The absorption efficiency, absorption capacity, flow resistance and color indication for the absorbent were tested and compared with some commercial products. The absorbent can reduce the carbon dioxide content in gases to 3.3 ppb (v/v) and absorbs not less than 35% of its weight of carbon dioxide. Besides its large capacity and sharp color indication, the absorbent has an outstanding advantage of small flow resistance in comparison with other commercial carbon dioxide absorbents. Applications in gas analysis and purification were also investigated.

  19. Comparison of disposable diapers with fluff absorbent and fluff plus absorbent polymers: effects on skin hydration, skin pH, and diaper dermatitis.

    Davis, J A; Leyden, J J; Grove, G L; Raynor, W J


    Diaper dermatitis results from the action of a number of physical and chemical factors on the skin. While its etiology is complex, there is agreement that prolonged contact between wet diapers and the skin leading to excessive hydration of the stratum corneum and reduced barrier function is a primary factor. Recent research also indicates that pH elevation resulting from ammonia production increases the probability of skin damage due to fecal enzyme activity. New diapers containing absorbent polymers blended with cellulose fluff in the absorbent core have been developed. The absorbent polymer binds fluids and controls pH in the diaper environment. To assess the effectiveness of these diapers, a clinical study was conducted with approximately 150 infants over 15 weeks, using fluff diapers and absorbent polymer diapers. The results clearly showed that the diapers with absorbent polymer provide a better skin environment than those with fluff only with respect to lower skin wetness and pH control (instrumental measurements). In addition, the clinicians' grades indicated a directional reduction in diaper rash severity.

  20. Slow and Fast Light in an Electro-Absorber

    Öhman, Filip; Bermejo Ramirez, Andres; Sales, Salvador


    We demonstrate controllable and large time delay in cascaded semiconductor saturable absorbers and amplifiers. The possibility of further increasing the tuneable phase shift by utilizing field screening effects in the quantum well absorber is demonstrated....

  1. Modeling the Effect of Polychromatic Light in Quantitative Absorbance Spectroscopy

    Smith, Rachel; Cantrell, Kevin


    Laboratory experiment is conducted to give the students practical experience with the principles of electronic absorbance spectroscopy. This straightforward approach creates a powerful tool for exploring many of the aspects of quantitative absorbance spectroscopy.

  2. Effect of inclusions' distribution on microwave absorbing properties of composites

    Qin, Siliang; Wang, Qingguo; Qu, Zhaoming


    Effect of inclusions' spatial distributions on the permeability and permittivity of composites is studied using the generalized Maxwell-Garnett equations. The result indicates that inclusions' orientation distribution can increase the longitudinal electromagnetic parameters. For inclusions' random and orientation distribution, single and three-layer absorbers are designed and optimized using genetic algorithm. The result shows that under a given absorbing requirement, absorber with inclusions' orientation distribution is lighter and thinner than absorber with inclusions' random distribution.

  3. Slow and Fast Light in an Electro-Absorber

    Öhman, Filip; Bermejo Ramirez, Andres; Sales, Salvador


    We demonstrate controllable and large time delay in cascaded semiconductor saturable absorbers and amplifiers. The possibility of further increasing the tuneable phase shift by utilizing field screening effects in the quantum well absorber is demonstrated.......We demonstrate controllable and large time delay in cascaded semiconductor saturable absorbers and amplifiers. The possibility of further increasing the tuneable phase shift by utilizing field screening effects in the quantum well absorber is demonstrated....

  4. Method for absorbing an ion from a fluid

    Gao, Huizhen; Wang, Yifeng; Bryan, Charles R.


    A method for absorbing an ion from a fluid by using dispersing an organic acid into an anion surfactant solution, mixing in a divalent-metal containing compound and a trivalent-metal containing compound and calcining the resulting solid layered double hydroxide product to form an absorbent material and then contacting the absorbent material with an aqueous solution of cations or anions to be absorbed.

  5. Design and analysis of crossover trials for absorbing binary endpoints.

    Nason, Martha; Follmann, Dean


    The crossover is a popular and efficient trial design used in the context of patient heterogeneity to assess the effect of treatments that act relatively quickly and whose benefit disappears with discontinuation. Each patient can serve as her own control as within-individual treatment and placebo responses are compared. Conventional wisdom is that these designs are not appropriate for absorbing binary endpoints, such as death or HIV infection. We explore the use of crossover designs in the context of these absorbing binary endpoints and show that they can be more efficient than the standard parallel group design when there is heterogeneity in individuals' risks. We also introduce a new two-period design where first period "survivors" are rerandomized for the second period. This design combines the crossover design with the parallel design and achieves some of the efficiency advantages of the crossover design while ensuring that the second period groups are comparable by randomization. We discuss the validity of the new designs and evaluate both a mixture model and a modified Mantel-Haenszel test for inference. The mixture model assumes no carryover or period effects while the Mantel-Haenszel approach conditions out period effects. Simulations are used to compare the different designs and an example is provided to explore practical issues in implementation.

  6. Material Model Evaluation of a Composite Honeycomb Energy Absorber

    Jackson, Karen E.; Annett, Martin S.; Fasanella, Edwin L.; Polanco, Michael A.


    A study was conducted to evaluate four different material models in predicting the dynamic crushing response of solid-element-based models of a composite honeycomb energy absorber, designated the Deployable Energy Absorber (DEA). Dynamic crush tests of three DEA components were simulated using the nonlinear, explicit transient dynamic code, LS-DYNA . In addition, a full-scale crash test of an MD-500 helicopter, retrofitted with DEA blocks, was simulated. The four material models used to represent the DEA included: *MAT_CRUSHABLE_FOAM (Mat 63), *MAT_HONEYCOMB (Mat 26), *MAT_SIMPLIFIED_RUBBER/FOAM (Mat 181), and *MAT_TRANSVERSELY_ANISOTROPIC_CRUSHABLE_FOAM (Mat 142). Test-analysis calibration metrics included simple percentage error comparisons of initial peak acceleration, sustained crush stress, and peak compaction acceleration of the DEA components. In addition, the Roadside Safety Verification and Validation Program (RSVVP) was used to assess similarities and differences between the experimental and analytical curves for the full-scale crash test.


    李宏; 阮航宇


    A new type microgap surge absorber fabricated by only semiconductor technique has in it a special structure silicon chip which forms microgaps for gas discharge with electrodes, and has advantages such as small size, low cost, suitability for mass production besides the desirable characteristics that common microgap surge absorbers have. Applications of this absorber in communication facilities are discussed.

  8. 21 CFR 886.3300 - Absorbable implant (scleral buckling method).


    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Absorbable implant (scleral buckling method). 886... SERVICES (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Prosthetic Devices § 886.3300 Absorbable implant (scleral buckling method). (a) Identification. An absorbable implant (scleral buckling method) is a...

  9. Graphene metamaterials based tunable terahertz absorber: effective surface conductivity approach

    Andryieuski, Andrei; Lavrinenko, Andrei


    In this paper we present the efficient design of functional thin-film metamaterial devices with the effective surface conductivity approach. As an example, we demonstrate a graphene based perfect absorber. After formulating the requirements to the perfect absorber in terms of surface conductivity...... we investigate the properties of graphene wire medium and graphene fishnet metamaterials and demonstrate both narrowband and broadband tunable absorbers....

  10. About sound mufflers sound-absorbing panels aircraft engine

    Dudarev, A. S.; Bulbovich, R. V.; Svirshchev, V. I.


    The article provides a formula for calculating the frequency of sound absorbed panel with a perforated wall. And although the sound absorbing structure is a set of resonators Helmholtz, not individual resonators should be considered in acoustic calculations, and all the perforated wall panel. The analysis, showing how the parameters affect the size and sound-absorbing structures in the absorption rate.

  11. Graphene metamaterials based tunable terahertz absorber: effective surface conductivity approach.

    Andryieuski, Andrei; Lavrinenko, Andrei V


    In this paper we present the efficient design of functional thin-film metamaterial devices with the effective surface conductivity approach. As an example, we demonstrate a graphene based perfect absorber. After formulating the requirements to the perfect absorber in terms of surface conductivity we investigate the properties of graphene wire medium and graphene fishnet metamaterials and demonstrate both narrowband and broadband tunable absorbers.

  12. Adaptive Seat Energy Absorbers for Enhanced Crash Safety: Technology Demonstration


    ARL-TR-7743 ● AUG 2016 US Army Research Laboratory Adaptive Seat Energy Absorbers for Enhanced Crash Safety: Technology...AUG 2016 US Army Research Laboratory Adaptive Seat Energy Absorbers for Enhanced Crash Safety: Technology Demonstration by Muthuvel...COVERED (From - To) 10 January 2012–29 February 2016 4. TITLE AND SUBTITLE Adaptive Seat Energy Absorbers for Enhanced Crash Safety: Technology

  13. 21 CFR 868.5300 - Carbon dioxide absorbent.


    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Carbon dioxide absorbent. 868.5300 Section 868...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5300 Carbon dioxide absorbent. (a) Identification. A carbon dioxide absorbent is a device intended for medical purposes that consists of...

  14. 21 CFR 868.5310 - Carbon dioxide absorber.


    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Carbon dioxide absorber. 868.5310 Section 868.5310...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5310 Carbon dioxide absorber. (a) Identification. A carbon dioxide absorber is a device that is intended for medical purposes and that is used in...

  15. [Absorbable coronary stents. New promising technology].

    Erbel, Raimund; Böse, Dirk; Haude, Michael; Kordish, Igor; Churzidze, Sofia; Malyar, Nasser; Konorza, Thomas; Sack, Stefan


    Coronary stent implantation started in Germany 20 years ago. In the beginning, the progress was very slow and accelerated 10 years later. Meanwhile, coronary stent implantation is a standard procedure in interventional cardiology. From the beginning of permanent stent implantation, research started to provide temporary stenting of coronary arteries, first with catheter-based systems, later with stent-alone technology. Stents were produced from polymers or metal. The first polymer stent implantation failed except the Igaki-Tamai stent in Japan. Newly developed absorbable polymer stents seem to be very promising, as intravascular ultrasound (IVUS) and optical coherence tomography have demonstrated. Temporary metal stents were developed based on iron and magnesium. Currently, the iron stent is tested in peripheral arteries. The absorbable magnesium stent (Biotronik, Berlin, Germany) was tested in peripheral arteries below the knee and meanwhile in the multicenter international PROGRESS-AMS (Clinical Performance and Angiographic Results of Coronary Stenting with Absorbable Metal Stents) study. The first magnesium stent implantation was performed on July 30, 2004 after extended experimental testing in Essen. The magnesium stent behaved like a bare-metal stent with low recoil of 5-7%. The stent struts were absorbed when tested with IVUS. Stent struts were not visible by fluoroscopy or computed tomography (CT) as well as magnetic resonance imaging (MRI). That means, that the magnesium stent is invisible and therefore CT and MRI can be used for imaging of interventions. Only using micro-CT the stent struts were visible. The absorption process could be demonstrated in a patient 18 days after implantation due to suspected acute coronary syndrome, which was excluded. IVUS showed a nice open lumen. Stent struts were no longer visible, but replaced by tissue indicating the previous stent location. Coronary angiography after 4 months showed an ischemia-driven target lesion

  16. [Performance of desulfurizing absorbent of roasted navajoite].

    Chen, Fang; Yang, Chun-ping; Gan, Hai-ming; Wu, Ting; Chen, Hai-lin; Chen, Hong; Xu, Ke-hui; Xie, Geng-xin


    An innovative flue gas desulfurization (FGD) coupling process was proposed in this study to overcome the problems in wet-type limestone/lime processes which include fouling, clogging, and difficulty of selling the by-products and the problems in traditional process for vanadium extraction from navajoite ore such as excessive consumption of sulfuric acid and emissions of pollutants. The performance of a jet bubbling reactor (JBR) at pilot-scale was evaluated using navajoite ore produced in the process of extracting vanadium pentoxide as desulfurization absorbent. Results showed that navajoite ore slurry achieved better desulfurization performance than limestone slurry. When the inlet flue gas pressure drop was 3.0 kPa, the gas flow was about 2350 m3 x h(-1) and the pH of the navajoite ore slurry was higher than 4.5, the desulfurization efficiency was stable about 90%. The SO2 removal efficiency appeared to increase along with the increasing of absorbent cycle-index. The efficiency of the second circulation was improved 3.5% compared to the first circulation. After an operating duration of 40 minutes, the leaching rate of vanadium pentoxide was about 20%, and reached 60% when the by-products were leached with 5% dilute sulfuric acid for 10 hours. The by-product from this process not only could be used to produce vanadium pentoxide which is a valuable industrial product, but also could significantly overcome the pollution problem existing in the traditional refining process of vanadium pentoxide when navajoite ore is used as the feed material. This FGD process using roasted navajoite slurry as absorbent is environmental sound and cost-effective, and shows the potential for application in the field of flue gas desulfurization as well as hydrometallurgy.

  17. A novel broadband waterborne acoustic absorber

    Wang, Changxian; Wen, Weibin; Huang, Yixing; Chen, Mingji; Lei, Hongshuai; Fang, Daining


    In this paper, we extended the ray tracing theory in polar coordinate system, and originally proposed the Snell-Descartes law in polar coordinates. Based on these theories, a novel broadband waterborne acoustic absorber device was proposed. This device is designed with gradient-distributing materials along radius, which makes the incidence acoustic wave ray warps. The echo reduction effects of this device were investigated by finite element analysis, and the numerical results show that the reflectivity of acoustic wave for the new device is lower than that of homogenous and Alberich layers in almost all frequency 0-30 kHz at the same loss factor.

  18. Absorbency of Superabsorbent Polymers in Cementitious Environments

    Esteves, Luis Pedro; Jensen, Ole Mejlhede


    Optimal use of superabsorbent polymers (SAP) in cement-based materials relies on knowledge on how SAP absorbency is influenced by different physical and chemical parameters. These parameters include salt concentration in the pore fluid, temperature of the system and SAP particle size. The present...... composition of the exposure liquid is investigated with atomic absorption spectroscopy. The paper provides the reader with knowledge about the absorption capacity of SAP in a cementitious environment, and how the absorption process may influence the cement pore fluid....

  19. DHCAL with Minimal Absorber: Measurements with Positrons

    Freund, B; Repond, J.; Schlereth, J.; Xia, L.; Dotti, A.; Grefe, C.; Ivantchenko, V.; Antequera, J.Berenguer; Calvo Alamillo, E.; Fouz, M.C.; Marin, J.; Puerta-Pelayo, J.; Verdugo, A.; Brianne, E.; Ebrahimi, A.; Gadow, K.; Göttlicher, P.; Günter, C.; Hartbrich, O.; Hermberg, B.; Irles, A.; Krivan, F.; Krüger, K.; Kvasnicka, J.; Lu, S.; Lutz, B.; Morgunov, V.; Provenza, A.; Reinecke, M.; Sefkow, F.; Schuwalow, S.; Tran, H.L.; Garutti, E.; Laurien, S.; Matysek, M.; Ramilli, M.; Schroeder, S.; Bilki, B.; Norbeck, E.; Northacker, D.; Onel, Y.; Cvach, J.; Gallus, P.; Havranek, M.; Janata, M.; Kovalcuk, M.; Kvasnicka, J.; Lednicky, D.; Marcisovsky, M.; Polak, I.; Popule, J.; Tomasek, L.; Tomasek, M.; Sicho, P.; Smolik, J.; Vrba, V.; Zalesak, J.; van Doren, B.; Wilson, G.W.; Kawagoe, K.; Hirai, H.; Sudo, Y.; Suehara, T.; Sumida, H.; Takada, S.; Tomita, T.; Yoshioka, T.; Bilokin, S.; Bonis, J.; Cornebise, P.; Pöschl, R.; Richard, F.; Thiebault, A.; Zerwas, D.; Hostachy, J.Y.; Morin, L.; Besson, D.; Chadeeva, M.; Danilov, M.; Markin, O.; Popova, E.; Gabriel, M.; Goecke, P.; Kiesling, C.; Kolk, N.van der; Simon, F.; Szalay, M.; Corriveau, F.; Blazey, G.C.; Dyshkant, A.; Francis, K.; Zutshi, V.; Kotera, K.; Ono, H.; Takeshita, T.; Ieki, S.; Kamiya, Y.; Ootani, W.; Shibata, N.; Jeans, D.; Komamiya, S.; Nakanishi, H.


    In special tests, the active layers of the CALICE Digital Hadron Calorimeter prototype, the DHCAL, were exposed to low energy particle beams, without being interleaved by absorber plates. The thickness of each layer corresponded approximately to 0.29 radiation lengths or 0.034 nuclear interaction lengths, defined mostly by the copper and steel skins of the detector cassettes. This paper reports on measurements performed with this device in the Fermilab test beam with positrons in the energy range of 1 to 10 GeV. The measurements are compared to simulations based on GEANT4 and a standalone program to emulate the detailed response of the active elements.

  20. Impedance matched thin metamaterials make metals absorbing.

    Mattiucci, N; Bloemer, M J; Aközbek, N; D'Aguanno, G


    Metals are generally considered good reflectors over the entire electromagnetic spectrum up to their plasma frequency. Here we demonstrate an approach to tailor their absorbing characteristics based on the effective metamaterial properties of thin, periodic metallo-dielectric multilayers by exploiting a broadband, inherently non-resonant, surface impedance matching mechanism. Based on this mechanism, we design, fabricate and test omnidirectional, thin ( 99%) over a frequency range spanning from the UV to the IR. Our approach opens new venues to design cost effective materials for many applications such as thermo-photovoltaic energy conversion devices, light harvesting for solar cells, flat panel display, infrared detectors, stray light reduction, stealth and others.

  1. Acoustical model of a Shoddy fibre absorber

    Manning, John Peter

    Shoddy fibres or "Shoddies" are a mixture of post-consumer and post-industrial fibres diverted from textile waste streams and recycled into their raw fibre form. They have found widespread use as a raw material for manufacturing sound absorbers that include, but are not limited to: automotive, architectural and home appliance applications. The purpose of this project is to develop a simple acoustic model to describe the acoustic behaviour of sound absorbers composed primarily of Shoddy fibres. The model requires knowledge of the material's bulk density only. To date, these materials have not been the focus of much published research and acoustical designers must rely on models that were developed for other materials or are overly complex. For modelling purposes, an equivalent fluid approach is chosen to balance complexity and accuracy. In deriving the proposed model, several popular equivalent fluid models are selected and the required input parameters for each model identified. The models are: the model of Delaney and Bazley, two models by Miki, the model of Johnson in conjunction with the model of Champoux and Allard and the model of Johnson in conjunction with the model of Lafarge. Characterization testing is carried out on sets of Shoddy absorbers produced using three different manufacturing methods. The measured properties are open porosity, tortuosity, airflow resistivity, the viscous and thermal characteristic lengths and the static thermal permeability. Empirical relationships between model parameters and bulk density are then derived and used to populate the selected models. This yields several 'simplified' models with bulk density as the only parameter. The most accurate model is then selected by comparing each model's prediction to the results of normal incidence sound absorption tests. The model of Johnson-Lafarge populated with the empirical relations is the most accurate model over the range of frequencies considered (approx. 300 Hz - 4000 Hz

  2. A variable passive low-frequency absorber

    Larsen, Niels Werner; Thompson, Eric Robert; Gade, Anders


    typically been too expensive or requires too much space to be practical for multi-purpose halls. Measurements were made on a variable low-frequency absorber to develop a practical solution to the dilemma. The paper will present the results of the measurements as well as a possible design.......Multi-purpose concert halls face a dilemma. They can host classical music concerts, rock concerts and spoken word performances in a matter of a short period. These different performance types require significantly different acoustic conditions in order to provide the best sound quality to both...

  3. Outflows vs. Clouds in AGN Intrinsic Absorbers

    Arav, Nahum


    We discuss the crucial role of a dynamical picture in the analysis of AGN intrinsic absorbers data. High quality FUSE data of Mrk 279 are used to demonstrate that the line of sight covering fraction is a strong function of velocity. In Mrk 279, as well as in most cases where the data is of high enough quality, the shape of the absorption troughs is mainly determined by the velocity-dependent covering fraction. We argue that the traditional ``cloud'' picture of AGN outflows is hard pressed to ...

  4. Sustained safety and performance of the second-generation drug-eluting absorbable metal scaffold in patients with de novo coronary lesions: 12-month clinical results and angiographic findings of the BIOSOLVE-II first-in-man trial

    Haude, Michael; Ince, Hüseyin; Abizaid, Alexandre; Toelg, Ralph; Lemos, Pedro Alves; von Birgelen, Clemens; Christiansen, Evald Høj; Wijns, William; Neumann, Franz-Josef; Kaiser, Christoph; Eeckhout, Eric; Lim, Soo Teik; Escaned, Javier; Onuma, Yoshinobu; Garcia-Garcia, Hector M.; Waksman, Ron


    Aims Metal absorbable scaffolds constitute a conceptually attractive alternative to polymeric scaffolds. Promising 6-month outcomes of a second-generation drug-eluting absorbable metal scaffold (DREAMS 2G), consisting of an absorbable magnesium scaffold backbone, have been reported. We assessed the

  5. Structure and activity relationships for amine based CO2 absorbents-I

    Singh, P.; Niederer, J. P. M.; Versteeg, G. F.


    A study to determine the structure and activity relationships of various amine based CO2 absorbents was performed in which, the absorption of pure CO2 at atmospheric pressure was measured to assess the total absorption rate and capacities. Results showed that an increase in chain length between the

  6. Structure and activity relationships for amine-based CO2 absorbents-II

    Niederer, J. P. M.; Versteeg, G. F.


    A study to determine the structure and activity relationships of various amine-based CO2 absorbents was performed, in which the absorption of pure CO2 at atmospheric pressure was measured to assess the total absorption rates and capacities. Steric hindrance effect was noticed when side chain with al

  7. Effects of Consecutive Wideband Tympanometry Trials on Energy Absorbance Measures of the Middle Ear

    Burdiek, Laina M.; Sun, Xiao-Ming


    Purpose: Wideband acoustic immittance (WAI) is a new technique for assessing middle ear transfer function. It includes energy absorbance (EA) measures and can be acquired with the ear canal pressure varied, known as "wideband tympanometry" (WBTymp). The authors of this study aimed to investigate effects of consecutive WBTymp testing on…

  8. Tracking Performances of Several Front-Absorber Designs

    Lautridou, P; CERN. Geneva; Métivier, V; Rahmani, A; Ramillien, V; Reposeur, T; Morsch, Andreas; Cussonneau, J P


    The tracking performances of the ALICE forward muon spectrometer are investigated for several front-absorbers designs. The obtained mass resolution is compared to the one of the absorber proposed in the LOI. Out of punchthrough considerations, two absorbers compositions, including a Carbon+Concrete sandwich design, allow to reach the requested mass resolution for the Y's. Almost identical behaviours are observed versus rapidity and transverse momentum of resonances for both new candidates. These proposed designs improve the mass resolution performances and could stand as suitable absorber options for the forward muon spectrometer of ALICE. The Carbon+Concrete absorber has been retained for the Technical Proposal [1].

  9. Heat Transfer Performance of Absorber of Absorption Refrigerating Machine

    Kunugi, Yoshifumi; Ouchi, Tomihisa; Usui, Sanpei; Fukuda, Tamio

    Experimental studies on heat transfer performance of absorber for lithium bromide-water absorption refrigerating machine are presented in this paper. Experimental apparatus for 35 kW evaporator and absorber, and outer grooved tubes are used. As a result, over-al1 coefficient of heat transmission of absorber has a maximum value, in the case of heat transfer area ratio of absorber to evaporator, is about 0.8. Heat transfer rate of absorber is increased by 60% by using the outer grooved tube compared with the plane surfaced tube.

  10. Warm absorbers in active galactic nuclei

    Reynolds, C S; Reynolds, C S; Fabian, A C


    Recent {\\it ASCA} observations confirm the presence of X-ray absorption due to partially ionized gas in many Seyfert 1 galaxies; the so-called warm absorber. Constraints on the location of the warm material are presented with the conclusion that this material lies at radii coincident with, or just outside, the broad-line region. The stability of this warm material to isobaric perturbations under the assumptions of thermal and photoionization equilibrium is also studied. It is shown that there is a remarkably small range of ionization parameter, \\xi, for which the warm absorber state is stable. The robustness of this result to changes in the shape of the primary continuum, the assumed density and optical depth is investigated. Given the constraints on the location and the stability properties of the material, several models for the environments of Seyfert nuclei are discussed. These attempt to explain the presence of significant amounts of partially ionized material. In particular, various models of the broad-...

  11. Possible Quantum Absorber Effects in Cortical Synchronization

    Kämpf, Uwe

    The Wheeler-Feynman transactional "absorber" approach was proposed originally to account for anomalous resonance coupling between spatio-temporally distant measurement partners in entangled quantum states of so-called Einstein-Podolsky-Rosen paradoxes, e.g. of spatio-temporal non-locality, quantum teleportation, etc. Applied to quantum brain dynamics, however, this view provides an anticipative resonance coupling model for aspects of cortical synchronization and recurrent visual action control. It is proposed to consider the registered activation patterns of neuronal loops in so-called synfire chains not as a result of retarded brain communication processes, but rather as surface effects of a system of standing waves generated in the depth of visual processing. According to this view, they arise from a counterbalance between the actual input's delayed bottom-up data streams and top-down recurrent information-processing of advanced anticipative signals in a Wheeler-Feynman-type absorber mode. In the framework of a "time-loop" model, findings about mirror neurons in the brain cortex are suggested to be at least partially associated with temporal rather than spatial mirror functions of visual processing, similar to phase conjugate adaptive resonance-coupling in nonlinear optics.

  12. An Energy Absorber with Force Modificator

    SU Hao; ZHANG Xiaowei; YU Tongxi


    Thin-walled tubes are extensively applied in engineering,especially in vehicle structures to resist axial or traversal impact loads,for their excellent energy absorbing capacity.However,in the axial deformation mode,the force history has an extremely high peak force which may bring not only fatal injury to occupants but also damage to structures,cargo and environment.Aiming to develop energy absorbers with impact-force modificator,square metal tube with force modificator is investigated which can monitor the force-deformation history of the tube.A small device is designed to serve as an impact-force modificator,which introduces desired imperfections to the square tube just before the impact happens between the impactor and the tube,so as to reduce the peak force.Prototypes with various governing parameters were manufactured and tested both quasi-statically and dynamically to study the effects of these parameters on the characteristics of energy absorption.The results show that the force modificator can achieve the desired reduction of the peak force well whilst remaining the specific energy absorption capacity of the original square tube.With future improvements,it could be applied to vehicles or roadside safety hardware to mitigate the consequences produced by traffic accidents.

  13. Absorber Alignment Measurement Tool for Solar Parabolic Trough Collectors: Preprint

    Stynes, J. K.; Ihas, B.


    As we pursue efforts to lower the capital and installation costs of parabolic trough solar collectors, it is essential to maintain high optical performance. While there are many optical tools available to measure the reflector slope errors of parabolic trough solar collectors, there are few tools to measure the absorber alignment. A new method is presented here to measure the absorber alignment in two dimensions to within 0.5 cm. The absorber alignment is measured using a digital camera and four photogrammetric targets. Physical contact with the receiver absorber or glass is not necessary. The alignment of the absorber is measured along its full length so that sagging of the absorber can be quantified with this technique. The resulting absorber alignment measurement provides critical information required to accurately determine the intercept factor of a collector.

  14. Nano-Composite Superfine Nickel Powder Double Absorbent Coating Designing

    LU Yan-hong; WANG Zhi-hui; HUANG Dong-zhen; HU Chuan-xin; ZHANG Chen-jia; LI Wan-zhi; LIANG Wen-ting


    We adopt a definite procedure to compound traditional absorbing material-superfine powder nickel and nano -SiC powder to obtain the nano-composite nickel powder, then testing the absorbing speciality of the composite powder. In virtue of computer assistant designing, we apply double-deck absorbent structure to improve absorbent effect and widen wave band. The experiment indicated that it is possible to achieve the anticipative object to improve the absorbing capability by adopting nano-composite absorbing material, but each component of the composite material must have matched electromagnetic parameter with another. For matching double-coating structure, it ought to modulate the correlativity of each factor to achieve the most matching in order to optimise the absorbent speciality.

  15. Clinical application of absorbable clips in hepatectomy

    ZHU Yu


    Full Text Available ObjectiveTo evaluate the feasibility of application of absorbable clips in hepatectomy for reducing intraoperative bleeding, operation time, and postoperative complications. MethodsA retrospective analysis was performed on the clinical data of 315 patients who underwent hepatectomy in the department of hepatobiliary surgery from January 2010 to July 2012. These patients were divided into observation group (n=149, among whom absorbable clips were used in hepatectomy, and control group (n=166, among whom the conventional surgical approach was used. Intraoperative bleeding, operation time, bile leakage, surgical site infection, liver failure, material and hospitalization expenses, and reoperation due to active bleeding at surgical wound were evaluated. Continuous data were analyzed by t test, and categorical data were analyzed by chi-square analysis and Fisher′s exact test. ResultsThe intraoperative bleeding was significantly less in the observation group than in the control group (34459±116.78 vs 582.90±216.17 ml, t=11.95, P<0.05. The operation time was significantly shorter in the observation group than in the control group (205.56±45.72 vs 270.84±33.87 min, t=14.47, P<0.05. The material expenses were significantly more in the observation group than in the control group (2849.36±84.75 vs 567.27±56.38 yuan, t=16.21, P<0.05, but there was no significant difference in hospitalization expenses between the observation group and control group (39 344.52±521.21 vs 38 872.43±426.05 yuan, t=0, P>0.05. After operation, bile leakage was found in one case in the observation group and 9 cases in the control group (χ2=5.765, P<0.05; surgical site infection was found in 2 cases in the observation group and in 15 cases in the control group (χ2=9.104, P<0.05; liver failure was found in 2 cases in the observation group and in 11 cases in the control group (χ2=5.541, P<0.05. No one underwent reoperation in the observation group, versus

  16. A chiral microwave absorbing absorbent of Fe–CoNiP coated on spirulina

    Xu, Yonggang, E-mail: [Science and Technology on Electromagnetic Scattering Laboratory, Shanghai, 200438 (China); Yuan, Liming [Science and Technology on Electromagnetic Scattering Laboratory, Shanghai, 200438 (China); Zhang, Deyuan [School of Mechanical Engineering and Automation, Beihang University, Beijing, 100191 (China)


    A chiral bio-absorbent of Fe–CoNiP coated on the spirulina was fabricated by the electroless and chemical vapor decomposition. The scanning electron microscopy (SEM) was used to evaluate the spirulina cells particle morphology. X-ray diffraction (XRD) patterns were done to analyze the particle crystal grain structure. The permittivity and permeability was measured by a vector network analyzer in frequency 8–18 GHz, and the reflection loss (RL) was calculated. The results showed the carbonyl iron particles (CIPs) and CoNiP were bonded to the spirulina surface, the permittivity and permeability could be enlarged as Fe films coated on the particles compared with the CoNiP spirulina, it was attributed to the excellent electromagnetic property of CIPs. The chiral Fe–CoNiP composites had a better absorbing property at 8–18 GHz than the CoNiP spirulina composite, the RL was −16.26 dB at 10.48 GHz, the absorbing band was 9.5–11.5 GHz of RL less than −10 dB, which indicated the Fe–CoNiP spirulina could be an effective absorbent used in 8–18 GHz. - Highlights: • Absorbers filled with Fe–CoNiP coating on the spirulina were fabricated. • The permittivity and permeability increased as CIPs coated. • The Fe material enhanced the electromagnetic property. • The spirulina coated Fe–CoNiP was effective in 8–18 GHz.

  17. Global Navigation Satellite System Multipath Mitigation Using a Wave-Absorbing Shield.

    Yang, Haiyan; Yang, Xuhai; Sun, Baoqi; Su, Hang


    Code multipath is an unmanaged error source in precise global navigation satellite system (GNSS) observation processing that limits GNSS positioning accuracy. A new technique for mitigating multipath by installing a wave-absorbing shield is presented in this paper. The wave-absorbing shield was designed according to a GNSS requirement of received signals and collected measurements to achieve good performance. The wave-absorbing shield was installed at the KUN1 and SHA1 sites of the international GNSS Monitoring and Assessment System (iGMAS). Code and carrier phase measurements of three constellations were collected on the dates of the respective installations plus and minus one week. Experiments were performed in which the multipath of the measurements obtained at different elevations was mitigated to different extents after applying the wave-absorbing shield. The results of an analysis and comparison show that the multipath was mitigated by approximately 17%-36% on all available frequencies of BeiDou Navigation Satellite System (BDS), Global Positioning System (GPS), and Global Navigation Satellite System (GLONASS) satellites. The three-dimensional accuracies of BDS, GPS, and GLONASS single-point positioning (SPP) were, respectively, improved by 1.07, 0.63 and 0.49 m for the KUN1 site, and by 0.72, 0.79 and 0.73 m for the SHA1 site. Results indicate that the multipath of the original observations was mitigated by using the wave-absorbing shield.

  18. PLD-grown thin film saturable absorbers

    Tellkamp, Friedjof


    The subject of this thesis is the preparation and characterization of thin films made of oxidic dielectrics which may find their application as saturable absorber in passively Q-switched lasers. The solely process applied for fabrication of the thin films was the pulsed laser deposition (PLD) which stands out against other processes by its flexibility considering the composition of the systems to be investigated. Within the scope of this thesis the applied saturable absorbers can be divided into two fundamentally different kinds of functional principles: On the one hand, saturable absorption can be achieved by ions embedded in a host medium. Most commonly applied bulk crystals are certain garnets like YAG (Y{sub 3}Al{sub 5}O{sub 12}) or the spinel forsterite (Mg{sub 2}SiO{sub 4}), in each case with chromium as dopant. Either of these media was investigated in terms of their behavior as PLD-grown saturable absorber. Moreover, experiments with Mg{sub 2}GeO{sub 4}, Ca{sub 2}GeO{sub 4}, Sc{sub 2}O{sub 3}, and further garnets like YSAG or GSGG took place. The absorption coefficients of the grown films of Cr{sup 4+}:YAG were determined by spectroscopic investigations to be one to two orders of magnitude higher compared to commercially available saturable absorbers. For the first time, passive Q-switching of a Nd:YAG laser at 1064 nm with Cr{sup 4+}:YAG thin films could be realized as well as with Cr:Sc{sub 2}O{sub 3} thin films. On the other hand, the desirable effect of saturable absorption can also be generated by quantum well structures. For this purpose, several layer system like YAG/LuAG, Cu{sub 2}O/MgO, and ZnO/corumdum were investigated. It turned out that layer systems with indium oxide (In{sub 2}O{sub 3}) did not only grew in an excellent way but also showed up a behavior regarding their photo luminescence which cannot be explained by classical considerations. The observed luminescence at roughly 3 eV (410 nm) was assumed to be of excitonic nature and its

  19. Corundum-based transparent infrared absorbers

    Schwingenschlögl, Udo


    Hypothetical corundum-based compounds are studied by electronic structure calculations. One quarter of the Al atoms in Al2O3 is replaced by a 3d transition metal from the M = Ti, ..., Zn (d1, ..., d9) series. Structure optimisations are performed for all the M-Al2O3 compounds and the electronic states are evaluated. Due to the M substitutes, narrow partially filled bands are formed at the Fermi energy. Beyond, for M = Ni and M = Cu the optical properties of Al2O3 in the visible range are conserved, while for M = Ti, ..., Co the systems form high accuracy optical filters. Since the compounds absorb the infrared radiation, the M = Ni and M = Cu systems are good candidates for heat-protective coatings. © 2009 Elsevier B.V. All rights reserved.

  20. Hydrogen heat treatment of hydrogen absorbing materials

    Park, Choong-Nyeon


    This study introduces the hydrogen heat treatment of hydrogen absorbing materials and its applicability for practical use. This treatment is somewhat different from normal heat treatment because of the interaction between metal atoms and hydrogen. Since hydrogen can be removed very fast by pumping it out the hydrogen-induced new lattice phase which can not be obtained without hydrogen can be preserved in a meta-stable state. A thermodynamic interpretation of the hydrogen heat treatment established previously was reformulated for graphical and analytical methods and applied to Pd-Pt-H and Pd-Ag-H alloy systems and a fair correlation between the calculation and experimental results was shown. The feasibility of applying the thermodynamic interpretation to intermetallic compounds-hydrogen systems was also discussed.

  1. Skin interaction with absorbent hygiene products.

    Runeman, Bo


    Skin problems due to the use of absorbent hygiene products, such as diapers, incontinence pads, and feminine sanitary articles, are mostly due to climate or chafing discomfort. If these conditions are allowed to prevail, these may develop into an irritant contact dermatitis and eventually superficial skin infections. Skin humidity and aging skin are among the most significant predisposing and aggravating factors for dermatitis development. Improved product design features are believed to explain the decline in observed diaper dermatitis among infants. Where adult incontinence-related skin problems are concerned, it is very important to apply a holistic perspective to understand the influences due to the individual's incontinence level and skin condition, as well as the hygiene and skin care measures provided. Individuals with frail, sensitive skin or with skin diseases may preferably have to use high-quality products, equipped with superabsorbent polymers and water vapor-permeable back sheets, to minimize the risk of skin complications.

  2. Post-treatments of Super Absorbent Polymer

    LIU Song; ZHOU Xiang; XING Zhi-qi


    Properties of high absorbency and modulus (gel rength) were both needed in applications of superabsorbent polymer (SAP). Generally, the absorption characteristic and gel strength reach a crossover point for a given system. Beyond this point, a given property will show improvement at the expense of another property. To synthesize SAP with properties superior to this optimum value, further modification in the process becomes essential. In our post-treatment modification of superabsorbent polymer, neither the variety of the crosslinkers, nor their amount was found the effective factors to the polymer performance, but the liquor ratio of the treating liquid to polymer. The combination of the chemical treating and heat-treating method was also explored. But this didn't put any positive effect on SAP's properties.

  3. Ultrathin microwave metamaterial absorber utilizing embedded resistors

    Kim, Young Ju; Hwang, Ji Sub; Yoo, Young Joon; Khuyen, Bui Xuan; Rhee, Joo Yull; Chen, Xianfeng; Lee, YoungPak


    We numerically and experimentally studied an ultrathin and broadband perfect absorber by enhancing the bandwidth with embedded resistors into the metamaterial structure, which is easy to fabricate in order to lower the Q-factor and by using multiple resonances with the patches of different sizes. We analyze the absorption mechanism in terms of the impedance matching with the free space and through the distribution of surface current at each resonance frequency. The magnetic field, induced by the antiparallel surface currents, is formed strongly in the direction opposite to the incident electromagnetic wave, to cancel the incident wave, leading to the perfect absorption. The corresponding experimental absorption was found to be higher than 97% in 0.88–3.15 GHz. The agreement between measurement and simulation was good. The aspects of our proposed structure can be applied to future electronic devices, for example, advanced noise-suppression sheets in the microwave regime.

  4. Hot Carrier extraction with plasmonic broadband absorbers

    Ng, Charlene; Dligatch, Svetlana; Roberts, Ann; Davis, Timothy J; Mulvaney, Paul; Gomez, Daniel E


    Hot charge carrier extraction from metallic nanostructures is a very promising approach for applications in photo-catalysis, photovoltaics and photodetection. One limitation is that many metallic nanostructures support a single plasmon resonance thus restricting the light-to-charge-carrier activity to a spectral band. Here we demonstrate that a monolayer of plasmonic nanoparticles can be assembled on a multi-stack layered configuration to achieve broad-band, near-unit light absorption, which is spatially localised on the nanoparticle layer. We show that this enhanced light absorbance leads to $\\sim$ 40-fold increases in the photon-to-electron conversion efficiency by the plasmonic nanostructures. We developed a model that successfully captures the essential physics of the plasmonic hot-electron charge generation and separation in these structures. This model also allowed us to establish that efficient hot carrier extraction is limited to spectral regions where the photons possessing energies higher than the S...

  5. Ultrathin microwave absorber based on metamaterial

    Kim, Y. J.; Yoo, Y. J.; Hwang, J. S.; Lee, Y. P.


    We suggest that ultrathin broadband metamaterial is a perfect absorber in the microwave regime by utilizing the properties of a resistive sheet and metamaterial. Meta-atoms are composed of four-leaf clover-shape metallic patterns and a metal plane separated by three intermediate resistive sheet layers between four dielectric layers. We interpret the absorption mechanism of the broadband by using the distribution of surface currents at specific frequencies. The simulated absorption was over 99% in 1.8-4.2 GHz. The corresponding experimental absorption was also over 99% in 2.62-4.2 GHz; however, the absorption was slightly lower than 99% in 1.8-2.62 GHz because of the sheet resistance and the changed values for the dielectric constant. Furthermore, it is independent of incident angle. The results of this research indicate the possibility of applications, due to the suppression of noxious exposure, in cell phones, computers and microwave equipments.

  6. Neutron absorbed dose in a pacemaker CMOS

    Borja H, C. G.; Guzman G, K. A.; Valero L, C. Y.; Banuelos F, A.; Hernandez D, V. M.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Calle Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Paredes G, L., E-mail: [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)


    The absorbed dose due to neutrons by a Complementary Metal Oxide Semiconductor (CMOS) has been estimated using Monte Carlo methods. Eventually a person with a pacemaker becomes a patient that must be treated by radiotherapy with a linear accelerator; the pacemaker has integrated circuits as CMOS that are sensitive to intense and pulsed radiation fields. When the Linac is working in Bremsstrahlung mode an undesirable neutron field is produced due to photoneutron reactions; these neutrons could damage the CMOS putting the patient at risk during the radiotherapy treatment. In order to estimate the neutron dose in the CMOS a Monte Carlo calculation was carried out where a full radiotherapy vault room was modeled with a W-made spherical shell in whose center was located the source term of photoneutrons produced by a Linac head operating in Bremsstrahlung mode at 18 MV. In the calculations a phantom made of tissue equivalent was modeled while a beam of photoneutrons was applied on the phantom prostatic region using a field of 10 x 10 cm{sup 2}. During simulation neutrons were isotropically transported from the Linac head to the phantom chest, here a 1 {theta} x 1 cm{sup 2} cylinder made of polystyrene was modeled as the CMOS, where the neutron spectrum and the absorbed dose were estimated. Main damages to CMOS are by protons produced during neutron collisions protective cover made of H-rich materials, here the neutron spectrum that reach the CMOS was calculated showing a small peak around 0.1 MeV and a larger peak in the thermal region, both connected through epithermal neutrons. (Author)

  7. Flexor Tenorrhaphy Using Absorbable Suture Materials

    Hyung Joo Kang


    Full Text Available Background Nonabsorbable sutures are favorable for repairing flexor tendons. However,absorbable sutures have performed favorably in an animal model.Methods Two-strand sutures using the interlocking modified Kessler method with polydioxanoneabsorbable sutures 4-0 were used to repair completely ruptured flexor tendons in 55 fingersfrom 41 consecutive patients. The medical records of average 42 follow up weeks were analyzedretrospectively. The data analyzed using the chi-squared test, and Fisher’s exact test was used forpostoperative complications. The results were compared with those of other studies.Results Among the index, middle, ring, and little fingers were injured in 9, 17, 16, and13 fingers, respectively. The injury levels varied from zone 1 to 5. Of the 55 digits in ourstudy, there were 26 (47% isolated flexor digitorum profundus (FDP injuries and 29 (53%combined FDP and with flexor digitorum superficialis injuries. Pulley repair was also conducted.Concomitant injuries of blood vessels and nerves were found in 17 patients (23 fingers; nerveinjuries occurred in 5 patients (10 fingers. Two patients had ruptures (3.6%, and one patienthad two adhesions (3.6%. Using the original Strickland criteria, all the patients were assessedto be excellent or good. Also, fibrosis and long-term foreign body tissue reactions such as stitchgranuloma were less likely occurred in our study. Compared to the Cullen’s report that usednonabsorbable sutures, there was no significant difference in the rupture or adhesion rates.Conclusions Therefore, this study suggests that appropriate absorbable core sutures can beused safely for flexor tendon repairs.

  8. 基于统一计算架构的人体受照剂量实时仿真评估方法%Real-time absorbed dose simulation assessment method for the maintenance workers of nuclear facilities based on compute unified device architecture

    杨子辉; 王静; 何桃; 宋婧; 龙鹏程


    基于统一计算架构(Compute unified device architecture, CUDA),利用GPU的流多处理器和共享显存实现了辐射环境中人体体素级受照剂量的并行计算。通过加速器驱动次临界系统散裂靶质子束窗的维修更换仿真例题的测试,百万量级体素人体受照剂量计算时间降低到10 ms的量级,能够保持与实时维修仿真同步。该方法能够满足维修仿真对维修人员的器官当量剂量和人体有效剂量计算的实时性要求,可应用到维修方案的实时仿真推演,对提高维修方案的设计与验证效率,辅助优化方案和保障人员辐射安全具有重要意义。%The absorbed dose assessment method was developed based on compute unified device architecture parallel architecture and human voxel model, to realize the parallel computing of radiation dose for human body in the radiation environment using the GPU processors and shared memory. The maintenance strategy simulation dose assessment of the spallation target proton beam window for accelerator driven system was tested by this method. The results showed that the computing time can reach 10 ms level with millions of voxel and the dose calculation can synchronize with real-time simulation of maintenance process.This method could realize the requirement of organ equivalent dose and effective dose calculation for maintenance worker. In the simulation deduction of maintenance strategy, this method is of great significance in protecting personnel radiation safety and improving the efficiency for  the design and validation of maintenance scheme.

  9. Space radiation absorbed dose distribution in a human phantom

    Badhwar, G. D.; Atwell, W.; Badavi, F. F.; Yang, T. C.; Cleghorn, T. F.


    The radiation risk to astronauts has always been based on measurements using passive thermoluminescent dosimeters (TLDs). The skin dose is converted to dose equivalent using an average radiation quality factor based on model calculations. The radiological risk estimates, however, are based on organ and tissue doses. This paper describes results from the first space flight (STS-91, 51.65 degrees inclination and approximately 380 km altitude) of a fully instrumented Alderson Rando phantom torso (with head) to relate the skin dose to organ doses. Spatial distributions of absorbed dose in 34 1-inch-thick sections measured using TLDs are described. There is about a 30% change in dose as one moves from the front to the back of the phantom body. Small active dosimeters were developed specifically to provide time-resolved measurements of absorbed dose rates and quality factors at five organ locations (brain, thyroid, heart/lung, stomach and colon) inside the phantom. Using these dosimeters, it was possible to separate the trapped-proton and the galactic cosmic radiation components of the doses. A tissue-equivalent proportional counter (TEPC) and a charged-particle directional spectrometer (CPDS) were flown next to the phantom torso to provide data on the incident internal radiation environment. Accurate models of the shielding distributions at the site of the TEPC, the CPDS and a scalable Computerized Anatomical Male (CAM) model of the phantom torso were developed. These measurements provided a comprehensive data set to map the dose distribution inside a human phantom, and to assess the accuracy and validity of radiation transport models throughout the human body. The results show that for the conditions in the International Space Station (ISS) orbit during periods near the solar minimum, the ratio of the blood-forming organ dose rate to the skin absorbed dose rate is about 80%, and the ratio of the dose equivalents is almost one. The results show that the GCR model dose

  10. Heat and mass transfer characteristics of a small helical absorber

    Yoon, Jung-In [College of Engineering, School of Mechanical Engineering, Pukyong National University, San 100, Yongdang-dong, Nam-gu, Pusan 608-739 (Korea, Republic of); Kwon, Oh-Kyung [KITECH, 35-3 Hongchon-ri, Ipjang-meon, Chonan, Chungnam 330-825 (Korea, Republic of); Bansal, P.K. [Department of Mechanical Engineering, The University of Auckland, Private bag 92019, Auckland (New Zealand); Moon, Choon-Geun; Lee, Ho-Saeng [Department of Refrigeration and Air-conditioning Engineering, Graduate School, Pukyong National University, San 100, Yongdang-dong, Nam-gu, Pusan 608-739 (Korea, Republic of)


    This paper presents experimental results of heat and mass transfer investigation of the falling film absorber (with strong lithium bromide solution) for a small household absorption chiller/heater. Various components (e.g. low temperature generator, absorber and evaporator) were arranged concentrically in cylindrical form such that the helical-arrangement of the heat exchangers allowed the system to be more compact than the conventional system. Measurements from the helical absorber were compared with data from the literature. The comparison revealed that the heat and mass transfer performance of the helical absorber tube is similar to the existing tube bundle absorber. As a result, the proposed helical absorber shows a good potential due its reduced size and weight for the future designs of small capacity absorption chillers/heaters. (author)

  11. Large area bismuth absorbers for X-ray microcalorimeters

    Vaillancourt, J.E. E-mail:; Allen, C.A.; Brekosky, R.; Dosaj, A.; Galeazzi, M.; Kelley, R.; Liu, D.; McCammon, D.; Porter, F.S.; Rocks, L.E.; Sanders, W.T.; Stahle, C.K


    Two challenges facing the use of large area (2 mmx2 mm) bismuth absorbers for microcalorimetry are uncertainties in the heat capacity of bismuth and the effects of lateral heat conduction and position dependence due to the absorber's large size. We have measured the heat capacity of three Bi samples to be 0.3-0.6 J K{sup -1} m{sup -3} at 100 mK. These absorbers also exhibit response variations as phonons created by an X-ray event at an absorber edge will take longer to propagate to the thermometer attachment point than those at the absorber center. This effect may degrade the detector's energy resolution if the propagation time is not very short compared to the thermometer time constant. We show that the response of the largest absorber varies by {approx}4% across its area.

  12. Study of Novel EUV Absorber : Nickel and Nickel Oxide

    Woo, Dong Gon; Kim, Jung Hwan; Kim, Jung Sik; Hong, Seongchul; Ahn, Jinho [Hanyang University, Seoul (Korea, Republic of)


    The shadowing effect is one of the most urgent issues yet to be solved in high-volume manufacturing using extreme ultraviolet lithography (EUVL). Many studies have been conducted to mitigate the unexpected results caused by shadowing effects. The simplest way to mitigate the shadowing effect is to reduce the thickness of the absorber. Since nickel has high extinction coefficients in the EUV wavelengths, it is one of more promising absorber material candidates. A Ni based absorber exhibited imaging performance comparable to a Tantalum nitride absorber. However, the Ni-based absorber showed a dramatic reduction in horizontal-vertical critical dimension (H-V CD) bias. Therefore, limitations in fabricating a EUV mask can be mitigated by using the Ni based absorber.

  13. Local Structure Analysis of Materials for Solar Cell Absorber Layer

    Jewell, Leila Elizabeth


    This dissertation examines solar cell absorber materials that have the potential to replace silicon in solar cells, including several copper-based sulfides and perovskites. Earth-abundant absorbers such as these become even more cost-effective when used in a nanostructured solar cell. Atomic layer deposition (ALD) and chemical vapor deposition (CVD) deposit highly conformal films and hence are important tools for developing extremely thin absorber solar cells with scalability. Thus, the prima...

  14. Design and Implementation of a Regenerative Shock Absorber

    Maravandi, Amir


    In this thesis, the development of a novel regenerative shock absorber sized for a passengercar suspension system is studied. In the first phase, DC and AC rotary machines along with charging circuits, to be used in the energy conversion stage of the proposed shock absorber are analyzed. In this analysis, the rotary damping coefficients provided by these systems are obtained following by experimental results.In the second phase, the development of a novel regenerative shock absorber in a proo...

  15. Light-absorbing impurities in Arctic snow

    S. J. Doherty


    Full Text Available Absorption of radiation by ice is extremely weak at visible and near-ultraviolet wavelengths, so small amounts of light-absorbing impurities in snow can dominate the absorption of solar radiation at these wavelengths, reducing the albedo relative to that of pure snow, contributing to the surface energy budget and leading to earlier snowmelt. In this study Arctic snow is surveyed for its content of light-absorbing impurities, expanding and updating the 1983–1984 survey of Clarke and Noone. Samples were collected in Alaska, Canada, Greenland, Svalbard, Norway, Russia, and the Arctic Ocean during 2005–2009, on tundra, glaciers, ice caps, sea ice, frozen lakes, and in boreal forests. Snow was collected mostly in spring, when the entire winter snowpack is accessible for sampling. Sampling was carried out in summer on the Greenland ice sheet and on the Arctic Ocean, of melting glacier snow and sea ice as well as cold snow. About 1200 snow samples have been analyzed for this study.

    The snow is melted and filtered; the filters are analyzed in a specially designed spectrophotometer system to infer the concentration of black carbon (BC, the fraction of absorption due to non-BC light-absorbing constituents and the absorption Ångstrom exponent of all particles. The reduction of snow albedo is primarily due to BC, but other impurities, principally brown (organic carbon, are typically responsible for ~40% of the visible and ultraviolet absorption. The meltwater from selected snow samples was saved for chemical analysis to identify sources of the impurities. Median BC amounts in surface snow are as follows (nanograms of carbon per gram of snow: Greenland 3, Arctic Ocean snow 7, melting sea ice 8, Arctic Canada 8, Subarctic Canada 14, Svalbard 13, Northern Norway 21, Western Arctic Russia 26, Northeastern Siberia 17. Concentrations are more variable in the European Arctic than in Arctic Canada or the Arctic Ocean, probably because of the proximity

  16. Decomposition-based recovery of absorbers in turbid media

    Campbell, S. D.; Goodin, I. L.; Grobe, S. D.; Su, Q.; Grobe, R.


    We suggest that the concept of the point-spread function traditionally used to predict the blurred image pattern of various light sources embedded inside turbid media can be generalized under certain conditions to predict also the presence and location of spatially localized absorbing inhomogeneities based on shadow point-spread functions associated with each localized absorber in the medium. The combined image obtained from several absorbers can then be decomposed approximately into the arithmetic sums of these individual shadow point-spread functions with suitable weights that can be obtained from multiple-regression analysis. This technique permits the reconstruction of the location of absorbers.

  17. Decomposition based recovery of absorbers in turbid media

    Goodin, Isaac; Rogers, Ben; Su, Q.; Grobe, R.


    We suggest that the concept of the point-spread function traditionally used to predict the blurred image pattern of various light sources embedded inside turbid media can be generalized under certain conditions to predict also the presence and location of spatially localized absorbing inhomogeneities based on shadow point spread functions associated with each localized absorber in the medium. The combined image obtained from several absorbers can then be decomposed approximately into the arithmetic sums of these individual shadow point spread functions with suitable weights that can be obtained from multiple regression analysis. This technique permits the reconstruction of the location of absorbers.


    KESKIN Reyhan


    Full Text Available Absorbency of textiles is defined as the ability of taking in a fluid in the manner of a sponge. Absorbency is required for comfort properties in so me clothes such as sportswear and underwear clothing, for drying properties in napkins, towels and bathrobes, for health concerns in some medical textiles such as bandages, gauze and absorbent cotton, and for cleaning properties in washclothes and mops. In this study five different fabric samples (three woven 100% cotton fabrics A, B and P respectively at plain, twill, and peshtamal weaving patterns and two 100% cotton terry towels T1 and T2 were tested. The absorbency properties of the samples were evaluated according to the droplet test, sinking time test and wicking height tests (pottasium chromate test. Peshtamal samples showed better absorbency results than plain and twill weaves and lower but close results to towel samples according to the droplet test, sinking time test and wicking height tests. The absorbency properties of peshtamals showed results close to towel samples. The void content of peshtamals is higher than plain and twill samples but closer and lower than towel samples. The good absorbency results of peshtamals might be due to the void content of peshtamals which is higher than plain and twill samples but closer and lower than towel samples. Peshtamals which are good in absorbency and light in weight might be used widespreadly in daily life for their high absorbency, and on travel for weight saving purposes.

  19. Optimal active vibration absorber - Design and experimental results

    Lee-Glauser, Gina; Juang, Jer-Nan; Sulla, Jeffrey L.


    An optimal active vibration absorber can provide guaranteed closed-loop stability and control for large flexible space structures with collocated sensors/actuators. The active vibration absorber is a second-order dynamic system which is designed to suppress any unwanted structural vibration. This can be designed with minimum knowledge of the controlled system. Two methods for optimizing the active vibration absorber parameters are illustrated: minimum resonant amplitude and frequency matched active controllers. The Controls-Structures Interaction Phase-1 Evolutionary Model at NASA LaRC is used to demonstrate the effectiveness of the active vibration absorber for vibration suppression. Performance is compared numerically and experimentally using acceleration feedback.

  20. Optimal active vibration absorber: Design and experimental results

    Lee-Glauser, Gina; Juang, Jer-Nan; Sulla, Jeffrey L.


    An optimal active vibration absorber can provide guaranteed closed-loop stability and control for large flexible space structures with collocated sensors/actuators. The active vibration absorber is a second-order dynamic system which is designed to suppress any unwanted structural vibration. This can be designed with minimum knowledge of the controlled system. Two methods for optimizing the active vibration absorber parameters are illustrated: minimum resonant amplitude and frequency matched active controllers. The Controls-Structures Interaction Phase-1 Evolutionary Model at NASA LaRC is used to demonstrate the effectiveness of the active vibration absorber for vibration suppression. Performance is compared numerically and experimentally using acceleration feedback.

  1. Simulated mixed absorbers and effective atomic numbers for attenuation

    K Karunakaran Nair; N Ramachandran; K K Abdullah; K M Varier


    The total -ray interaction crosss-sections on mixed absorbers were determined at 662 keV with a view to study the effective atomic numbers for -ray absorption under narrow beam good geometry set-up. The measurements were taken for the combination of metallic absorbers like aluminium, copper, lead and mercury and also for the simulated absorbers by rotating the targets. ORTEC HPGe and NaI(Tl) detectors were used for detection of -rays.The experimental results compare favourably with theoretical values derived from XCOM package and suggest the usefulness of the concept of effective atomic numbers and the utility of the rotating absorbers technique.

  2. Semiconductor nanowire optical antenna solar absorbers.

    Cao, Linyou; Fan, Pengyu; Vasudev, Alok P; White, Justin S; Yu, Zongfu; Cai, Wenshan; Schuller, Jon A; Fan, Shanhui; Brongersma, Mark L


    Photovoltaic (PV) cells can serve as a virtually unlimited clean source of energy by converting sunlight into electrical power. Their importance is reflected in the tireless efforts that have been devoted to improving the electrical and structural properties of PV materials. More recently, photon management (PM) has emerged as a powerful additional means to boost energy conversion efficiencies. Here, we demonstrate an entirely new PM strategy that capitalizes on strong broad band optical antenna effects in one-dimensional semiconductor nanostructures to dramatically enhance absorption of sunlight. We show that the absorption of sunlight in Si nanowires (Si NWs) can be significantly enhanced over the bulk. The NW's optical properties also naturally give rise to an improved angular response. We propose that by patterning the silicon layer in a thin film PV cell into an array of NWs, one can boost the absorption for solar radiation by 25% while utilizing less than half of the semiconductor material (250% increase in the light absorption per unit volume of material). These results significantly advance our understanding of the way sunlight is absorbed by one-dimensional semiconductor nanostructures and provide a clear, intuitive guidance for the design of efficient NW solar cells. The presented approach is universal to any semiconductor and a wide range of nanostructures; as such, it provides a new PV platform technology.

  3. Light absorbing carbon emissions from commercial shipping

    Lack, Daniel; Lerner, Brian; Granier, Claire; Baynard, Tahllee; Lovejoy, Edward; Massoli, Paola; Ravishankara, A. R.; Williams, Eric


    Extensive measurements of the emission of light absorbing carbon aerosol (LAC) from commercial shipping are presented. Vessel emissions were sampled using a photoacoustic spectrometer in the Gulf of Mexico region. The highest emitters (per unit fuel burnt) are tug boats, thus making significant contributions to local air quality in ports. Emission of LAC from cargo and non cargo vessels in this study appears to be independent of engine load. Shipping fuel consumption data (2001) was used to calculate a global LAC contribution of 133(+/-27) Ggyr-1, or ~1.7% of global LAC. This small fraction could have disproportionate effects on both air quality near port areas and climate in the Arctic if direct emissions of LAC occur in that region due to opening Arctic sea routes. The global contribution of this LAC burden was investigated using the MOZART model. Increases of 20-50 ng m-3 LAC (relative increases up to 40%) due to shipping occur in the tropical Atlantic, Indonesia, central America and the southern regions of South America and Africa.

  4. Absorber Coatings for Mid-Infrared Astrophysics

    Baker, Dahlia Anne; Wollack, Edward; Rostem, Karwan


    Control over optical response is an important aspect of instrument design for astrophysical imaging. Here we consider a mid-infrared absorber coating proposed for use on HIRMES (High Resolution Mid-Infrared Spectrometer), a cryogenic spectrometer which will fly on the SOFIA (Stratospheric Observatory for Infrared Astronomy) aircraft. The aim of this effort is to develop an absorptive coating for the 20-200 microns spectral range based on a graphene loaded epoxy binder (Epotek 377H) and glass microsphere scatterers (3M K1). The coatings electromagnetic response was modeled using a Matlab script and the glass microspheres were characterized by the measured size distribution, the dielectric constant, and the filling fraction. Images of the microspheres taken by a microscope were used to determine the size distribution with an ImageJ particle analysis program. Representative test samples for optical evaluation were fabricated for characterization via infrared Fourier transform spectroscopy. The optical tests will determine the material’s absorptance and reflectance. These test results will be compared to the modeled response.

  5. A variable passive low-frequency absorber

    Larsen, Niels Werner; Thompson, Eric R.; Gade, Anders Christian


    Multi-purpose concert halls face a dilemma. They can host classical music concerts, rock concerts and spoken word performances in a matter of a short period. These different performance types require significantly different acoustic conditions in order to provide the best sound quality to both the performers and the audience. A recommended reverberation time for classical music may be in the range of 1.5-2 s for empty halls, where rock music sounds best with a reverberation time around 0.8-1 s. Modern rhythmic music often contains high levels of sound energy in the low frequency bands but still requires a high definition for good sound quality. Ideally, the absorption of the hall should be adjustable in all frequency bands in order to provide good sound quality for all types of performances. The mid and high frequency absorption is easily regulated, but adjusting the low-frequency absorption has typically been too expensive or requires too much space to be practical for multi-purpose halls. Measurements were made on a variable low-frequency absorber to develop a practical solution to the dilemma. The paper will present the results of the measurements as well as a possible design.

  6. Laser beam propagation in non-linearly absorbing media

    Forbes, A


    Full Text Available Many analytical techniques exist to explore the propagation of certain laser beams in free space, or in a linearly absorbing medium. When the medium is nonlinearly absorbing the propagation must be described by an iterative process using the well...

  7. 14 CFR 29.475 - Tires and shock absorbers.


    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Tires and shock absorbers. 29.475 Section... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Strength Requirements Ground Loads § 29.475 Tires and shock absorbers. Unless otherwise prescribed, for each specified landing condition, the tires must...

  8. 14 CFR 27.475 - Tires and shock absorbers.


    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Tires and shock absorbers. 27.475 Section... AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Strength Requirements Ground Loads § 27.475 Tires and shock absorbers. Unless otherwise prescribed, for each specified landing condition, the tires must be assumed...

  9. Effects of Root-Growing Space on Its Absorbing Characteristics

    SONG Hai-xing; LI Sheng-xiu


    Influences of root-growing space of maize upon root physiological characteristics, nutrient uptake and crop yields were studied under conditions with and without supply of water and N. Results showed that limitation of the root-growing space greatly affected root growth, decreased total root-absorbing area and TTC-reductive amounts. However, it obviously increased the root active-absorbing area, specific absorbing area (absorbing area per gram root weight) and specific active-absorbing area (actively absorbing area per gram root weight) in addition to promoting the TTC-reductive intensity. This clearly showed that plants were not passively tolerant to stress, but actively regulated their physiological metabolic processes, and strengthened their absorbing ability to increase water and nutrient uptake so that root injury by the environmental stress could be reduced. Supply of water and N stimulated root growth, increased root-absorbing area and activity, promoted nutrient uptake, and therefore increased crop yield and decreased the detrimental effects resulting from the limitation of roots-growing space.

  10. A blast absorber test: measurement and model results

    Eerden, F.J.M. van der; Berg, F. van den; Hof, J. van 't; Arkel, E. van


    A blast absorber test was conducted at the Aberdeen Test Centre from 13 to 17 June 2005. The test was set up to determine the absorbing and shielding effect of a gravel pile, of 1.5 meters high and 15 by 15 meters wide, on blasts from large weapons: e.g. armor, artillery or demolition. The blast was

  11. Preparation of Superabsorbent Polymers with Increased Saline Absorbency

    LIU Song; JIN Yi-fen; ZHOU Xiang


    Superabsorbent having enhanced absorbency of 0.9%NaCl solution was synthesized on one basis of incorporating zwitterionic (sulfobetaine) monomer into the previous monomer mixture, which comprises ionic (AA) and nonionic monomers, and another basis of introducing inorganic salt B. As far as saline absorbency is concerned, introduction of inorganic salt B is more useful than the sulfobetaine monomer.

  12. Photochromic And Thermochromic Pigments For Solar Absorbing-Reflecting Coatings

    Novinson, Thomas


    Both photochromic and thermochromic compounds were synthesized and physical measurements were made to determine coefficients of relectance, absorbance and emission. The most interesting group of thermochromic compounds are related to silver tctraiodomercurate and the most interesting photochromic compounds are substituted benzoindolinopyrospirans. The synthesis and optical reflectance and absorbance properties of other classes of compounds are also reported.

  13. Contributions to the Study of Dynamic Absorbers, a Case Study

    Monica Balcau


    Full Text Available Dynamic absorbers are used to reduce torsional vibrations. This paper studies the effect of a dynamic absorber attached to a mechanical system formed of three reduced masses which are acted on by one, two or three order x harmonics of a disruptive force.

  14. Why muscle is an efficient shock absorber.

    Michael A Ferenczi

    Full Text Available Skeletal muscles power body movement by converting free energy of ATP hydrolysis into mechanical work. During the landing phase of running or jumping some activated skeletal muscles are subjected to stretch. Upon stretch they absorb body energy quickly and effectively thus protecting joints and bones from impact damage. This is achieved because during lengthening, skeletal muscle bears higher force and has higher instantaneous stiffness than during isometric contraction, and yet consumes very little ATP. We wish to understand how the actomyosin molecules change their structure and interaction to implement these physiologically useful mechanical and thermodynamical properties. We monitored changes in the low angle x-ray diffraction pattern of rabbit skeletal muscle fibers during ramp stretch compared to those during isometric contraction at physiological temperature using synchrotron radiation. The intensities of the off-meridional layer lines and fine interference structure of the meridional M3 myosin x-ray reflection were resolved. Mechanical and structural data show that upon stretch the fraction of actin-bound myosin heads is higher than during isometric contraction. On the other hand, the intensities of the actin layer lines are lower than during isometric contraction. Taken together, these results suggest that during stretch, a significant fraction of actin-bound heads is bound non-stereo-specifically, i.e. they are disordered azimuthally although stiff axially. As the strong or stereo-specific myosin binding to actin is necessary for actin activation of the myosin ATPase, this finding explains the low metabolic cost of energy absorption by muscle during the landing phase of locomotion.

  15. Assessment

    Geoff Brindley


    @@ Introduction TERMINOLOGY AND KEY CONCEPTS The term assessment refers to a variety of ways of collecting information on a learner's language ability or achievement. Although testing and assessment are often used interchangeably, the latter is an umbrella term encompassing measurement instruments administered on a ‘one-off’ basis such as tests, as well as qualitative methods of monitoring and recording student learning such as observation, simulations of project work. Assessment is also distinguished from evaluation which is concerned with the overall language programme and not just with what individual students have learnt. Proficiency assessment refers to the assessment of general language abilities acquired by the learner independent of a course of study.This kind of assessment is often done through the administration of standardised commercial language-proficency tests. On the other hand, assessment of achievement aims to establish what a student had learned in relation to a particular course or curriculum (thus frequently carried out by the teacher) .Achievement assesssment may be based either on the specific content of the course or on the course objectives (Hughes 1989).

  16. Thermally Induced Nonlinear Optical Absorption in Metamaterial Perfect Absorbers

    Guddala, Sriram; Ramakrishna, S Anantha


    A metamaterial perfect absorber consisting of a tri-layer (Al/ZnS/Al) metal-dielectric-metal system with top aluminium nano-disks is fabricated by laser-interference lithography and lift-off processing. The metamaterial absorber had peak resonant absorbance at 1090 nm and showed nonlinear absorption for 600ps laser pulses at 1064 nm wavelength. A nonlinear saturation of reflectance was measured to be dependent on the average laser power incident and not the peak laser intensity. The nonlinear behaviour is shown to arise from the heating due to the absorbed radiation and photo-thermal changes in the dielectric properties of aluminium. The metamaterial absorber is seen to be damage resistant at large laser intensities of 25 MW/cm2.

  17. Dynamic Vibration Absorber with Negative Stiffness for Rotor System

    Hongliang Yao


    Full Text Available To suppress the vibration of a rotor system, a vibration absorber combining negative stiffness with positive stiffness together is proposed in this paper. Firstly, the negative stiffness producing mechanism using ring type permanent magnets is presented and the characteristics of the negative stiffness are analyzed. Then, the structure of the absorber is proposed; the principles and nonlinear dynamic characteristics of the absorber-rotor system are studied numerically. Finally, experiments are carried out to verify the numerical conclusions. The results show that the proposed vibration absorber is effective to suppress the vibration of the rotor system, the nonlinearity of the negatives stiffness affects the vibration suppression effect little, and the negative stiffness can broaden the effective vibration control frequency range of the absorber.

  18. Performance evaluation of CFRP-rubber shock absorbers

    Lamanna, Giuseppe, E-mail:; Sepe, Raffaele, E-mail: [Department of Industrial and Information Engineering, Second University of Naples, via Roma, 29 - 81031 Aversa (Italy)


    In the present work a numerical investigation on the energy absorbing capability of dedicated structural components made of a carbon fiber reinforced polymer and an emulsion polymerised styrene butadiene rubber is reported. The shock absorbers are devices designed to absorb large amounts of energy by sacrificing their own structural integrity. Their aim is to cushion the effects of an impact phenomenon with the intent to preserve other structures from global failure or local damaging. Another important role of shock absorbers is reducing the peak of the acceleration showed during an impact phenomenon. This effect is of considerable interest in the case of vehicles to preserve passengers’ safety. Static and dynamic numerical results are compared with experimental ones in terms of mean crushing forces, energy and peak crushing. The global performance of the absorbers has been evaluated by referencing to a proposed quality index.

  19. Tunable THz perfect absorber using graphene-based metamaterials

    Faraji, Mahboobeh; Moravvej-Farshi, Mohammad Kazem; Yousefi, Leila


    A tunable THz absorber, with absorbance more than 90% is proposed, and numerically characterized. The absorber structure is based on metamaterials with unit cells consisting of two patterned graphene layers separated by a 5-nm thick layer of Al2O3. Numerical results show that when the chemical potential of the top graphene microribbons are tuned by an external variable bias and that of the lower graphene fishnet is kept at μC=0, frequency of the absorption peaks can be tuned as desired, therefore we can have a tunable or switchable absorber. The proposed absorber can have applications in designing tunable reflective THz filters or tunable THz switches and modulators. It can also be used for cloaking objects in THz range.

  20. Graphene Based Terahertz Absorber Designed With Effective Surface Conductivity Approach

    Andryieuski, Andrei; Pizzocchero, Filippo; Booth, Tim

    Young field of terahertz (THz) science and technology demands new materials and devices, such as filters, modulators, polarization converters and absorbers. Graphene, a recently discovered single-atom-thick material, provides exciting properties for functional terahertz applications. Graphene...... conductivity and how to use it in optical design. We demonstrate a tunable THz perfect absorber, which consists of continuous graphene various structured graphene metamaterials above a metal mirror. Changing the Fermi level from 0 eV to 0.5 eV allows for drastic changes in absorbance from less than 0.1 to 1...... in the working range. We demonstrate the possibility of the absorber bandwidth control with the metamaterial’s unit cell geometry. The results of fabrication and characterization of the THz graphene metamaterials based absorbers will be presented at the conference....

  1. Magnetically rotational reactor for absorbing benzene emissions by ionic liquids

    Yangyang; Jiang; Chen; Guo; Huizhou; Liu


    A magnetically rotational reactor (MRR) has been developed and used in absorbing benzene emissions. The MRR has a permanent magnet core and uses magnetic ionic liquid [bmim]FeCl4 as absorbent. Benzene emissions were carried by N2 into the MRR and were absorbed by the magnetic ionic liquid. The rotation of the permanent magnet core provided impetus for the agitation of the magnetic ionic liquid, enhancing mass transfer and making benzene better dispersed in the absorbent. 0.68 g benzene emissions could be absorbed by a gram of [bmim]FeCl4, 0.27 and 0.40 g/ghigher than that by [bmim]PF6 and [bmim]BF4, respectively. The absorption rate increased with increasing rotation rate of the permanent magnet.

  2. Structure and Performance Analysis of Regenerative Electromagnetic Shock Absorber

    Longxin Zhen


    Full Text Available This paper analyzed the structure and principle of a regenerative electromagnetic shock absorber in detail. The innovative shock absorber resembles linear generator in principle and can generate electric power through the relative reciprocating motion between coil assembly and permanent magnet assembly. At the same time, the damping can remove discomfort caused by road roughness. The regenerated electric power can be recovered through battery. Analysis of magnetic flux density of the permanent magnet array of the innovative shock absorber was performed using ANSYS software based on the structure parameters given in the paper,then the performance parameters of the shock absorber was determined . Analysis and calculation results prove the viability of this shock absorber.

  3. Absorber-evaporator unit for an absorption-refrigeration system

    Hallatt, R.J.; Rorschach, R.L.


    This low temperature absorption-refrigeration system uses an absorber-evaporator. A conduit is connected between the upper portion of the absorber and the lower portion of the evaporator to conduct inert gas from the absorber to the evaporator. A second conduit connects the upper portion of the evaporator to the lower portion of the absorber and a blower in this conduit circulates the inert gas through the closed system. By placing the blower between the evaporator ad the absorber, the pressure in the evaporator is maintained at a minimum so that the working temperature is as low as possible. The medium to be cooled by the refrigerant is circulated through a heat exchanger located within the evaporator, whereby the latent heat of vaporization of the liquid refrigerant is employed to cool the outside medium. (2 claims)

  4. New Technology in Hydrogen Absorbers for Muon Cooling Channels

    Cummings, M A C


    Ionization cooling is the only technique fast enough to cool and focus muons for neutrino factories and muon colliders, and hydrogen is the optimal material for maximum cooling and minimal multiple scattering. Liquid hydrogen absorber R&D for the Muon Collaboration has proceeded on parallel and complementary fronts. The continuing LH2 absorber engineering and technical developments by the MuCool group conducted by ICAR* institutions (NIU, IIT and UIUC), the University of Mississippi and Oxford University, in cooperation with Fermilab, will be summarized, including results from the first hydrogen absorber tests at the newly constructed FNAL Mucool Test Area (MTA). The program includes designs for the high-powered test of an absorber prototype (external heat exchange) at the MTA which are nearing completion to be installed by summer 2005, an alternative absorber design (internal heat exchange) being finalized for the approved cooling experiment (MICE) at Rutherford-Appleton Laboratory, and a novel idea for ...

  5. Multilayer metamaterial absorbers inspired by perfectly matched layers

    Pastuszczak, Anna; Antosiewicz, Tomasz J; Kotynski, Rafal


    We derive periodic multilayer absorbers with effective uniaxial properties similar to perfectly matched layers (PML). This approximate representation of PML is based on the effective medium theory and we call it an effective medium PML (EM-PML). We compare the spatial reflection spectrum of the layered absorbers to that of a PML material and demonstrate that after neglecting gain and magnetic properties, the absorber remains functional. This opens a route to create electromagnetic absorbers for real and not only numerical applications and as an example we introduce a layered absorber for the wavelength of $8$~$\\mu$m made of SiO$_2$ and NaCl. We also show that similar cylindrical core-shell nanostructures derived from flat multilayers also exhibit very good absorptive and reflective properties despite the different geometry.

  6. Improvement on the wave absorbing property of a lossy frequency selective surface absorber using a magnetic substrate

    Sun Liang-Kui; Cheng Hai-Feng; Zhou Yong-Jiang; Wang Jun


    An equivalent-circuit model is used to analyse the improvement of the wave absorbing performance of the lossy frequency selective surface(FSS)absorber by using a magnetic substrate,showing that it is possible to widen the wave absorbing bandwidth.Three pieces of magnetic substrates are prepared.According to the complex permittivity and permeability,the reflectivity of the corresponding absorber is calculated by the finite difference time-domain(FDTD)method,and the bandwidth of the reflectivity below-10 dB is optimized by genetic algorithm.The calculated results indicate that the wave absorbing performance is significantly improved by increasing the complex permeability of the substrate; the reflectivity bandwidth below-10 dB of the single layer FSS absorber can reach 3.6-18 GHz with a thickness of 5 mm,which is wider than that with a dielectric substrate.The density of the FSS absorber is only 0.92 g/cm3.Additionally,the absorption band can be further widened by inserting a second lossy FSS.Finally,a double layer lossy FSS absorber with a magnetic substrate is fabricated based on the design result.The experimental result is consistent with the design one.

  7. Middle ear packing materials: comparison between absorbable hemostatic gelatine sponge and sugarcane biopolymer sponge in rats

    Débora Lopes Bunzen


    Full Text Available INTRODUCTION: Several biomaterials can be used in ear surgery to pack the middle ear or support the graft. The absorbable gelatin sponge is the most widely used, but it may produce fibrosis and impair ventilation of the middle ear. OBJECTIVE: This experimental study aimed to investigate the inflammatory effects of the sugarcane biopolymer sponge (BP in the rat middle ear compared with absorbable gelatin sponge (AGS. MATERIALS AND METHODS: Prospective experimental study design. Thirty adult female Wistar rats were allocated to receive the BP sponge into the right ear and AGS into the left ear. Animals were randomly killed at 4 and 12 weeks post-procedure. Qualitative histological assessments were performed to evaluate the inflammatory reaction in the tympanic bullae. RESULTS: The BP sponge caused inflammation more intense and persistent than AGS. The BP was not absorbed during the experiment. Fibrosis was observed only in the ears with AGS. There were thickening of the mucosa and neoangiogenesis in the group of AGS. CONCLUSION: Despite inflammation, the BP sponge produced less fibrosis and neoangiogenesis compared to AGS. The sponge BP appeared to be a non-absorbable biomaterial in the middle ear.

  8. Food-processes wastewaters treatment using food solid-waste materials as adsorbents or absorbents

    Rapti, Ilaira; Georgopoulos, Stavros; Antonopoulou, Maria; Konstantinou, Ioannis; Papadaki, Maria


    The wastewaters generated by olive-mills during the production of olive oil, wastewaters from a dairy and a cow-farm unit and wastewaters from a small food factory have been treated by means of selected materials, either by-products of the same units, or other solid waste, as absorbents or adsorbents in order to identify the capacity of those materials to remove organic load and toxicity from the aforementioned wastewaters. The potential of both the materials used as absorbents as well as the treated wastewaters to be further used either as fertilizers or for agricultural irrigation purposes are examined. Dry olive leaves, sheep wool, rice husks, etc. were used either in a fixed-bed or in a stirred batch arrangemen,t employing different initial concentrations of the aforementioned wastewaters. The efficiency of removal was assessed using scpectrophotometric methods and allium test phytotoxicity measurements. In this presentation the response of each material employed is shown as a function of absorbent/adsorbent quantity and kind, treatment time and wastewater kind and initial organic load. Preliminary results on the potential uses of the adsorbents/absorbents and the treated wastewaters are also shown. Keywords: Olive-mill wastewaters, dairy farm wastewaters, olive leaves, zeolite, sheep wool

  9. Microwave absorbance properties of zirconium–manganese substituted cobalt nanoferrite as electromagnetic (EM) wave absorbers

    Khan, Kishwar, E-mail:; Rehman, Sarish


    Highlights: • Good candidates for EM materials with low reflectivity. • Good candidates for broad bandwidth at microwave frequency. • Microwave absorbing bandwidth was modulated simply by manipulating the Zr–Mn. • Higher the Zr–Mn content, the higher absorption rates for the electromagnetic radiation. • The predicted reflection loss shows that this can be used for thin ferrite absorber. - Abstract: Nanocrystalline Zr–Mn (x) substituted Co ferrite having chemical formula CoFe{sub 2−2x}Zr{sub x}Mn{sub x}O{sub 4} (x = 0.1–0.4) was prepared by co-precipitation technique. Combining properties such as structural, electrical, magnetic and reflection loss characteristics. Crystal structure and surface morphology of the calcined samples were characterized by X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM). By using two point probe homemade resistivity apparatus to find resistivity of the sample. Electromagnetic (EM) properties are measured through RF impedance/materials analyzer over 1 MHz–3 GHz. The room-temperature dielectric measurements show dispersion behavior with increasing frequency from 100 Hz to 3 MHz. Magnetic properties confirmed relatively strong dependence of saturation magnetization on Zr–Mn composition. Curie temperature is also found to decrease linearly with addition of Zr–Mn. Furthermore, comprehensive analysis of microwave reflection loss (RL) is carried out as a function of substitution, frequency, and thickness. Composition accompanying maximum microwave absorption is suggested.

  10. Nonlinear dynamic model for magnetically-tunable Galfenol vibration absorbers

    Scheidler, Justin J.; Dapino, Marcelo J.


    This paper presents a single degree of freedom model for the nonlinear vibration of a metal-matrix composite manufactured by ultrasonic additive manufacturing that contains seamlessly embedded magnetostrictive Galfenol alloys (FeGa). The model is valid under arbitrary stress and magnetic field. Changes in the composite's natural frequency are quantified to assess its performance as a semi-active vibration absorber. The effects of Galfenol volume fraction and location within the composite on natural frequency are quantified. The bandwidth over which the composite's natural frequency can be tuned with a bias magnetic field is studied for varying displacement excitation amplitudes. The natural frequency is tunable for all excitation amplitudes considered, but the maximum tunability occurs below an excitation amplitude threshold of 1 × 10-6 m for the composite geometry considered. Natural frequency shifts between 6% and 50% are found as the Galfenol volume fraction varies from 25% to 100% when Galfenol is located at the composite neutral axis. At a modest 25% Galfenol by volume, the model shows that up to 15% shifts in composite resonance are possible through magnetic bias field modulation if Galfenol is embedded away from the composite midplane. As the Galfenol volume fraction and distance between Galfenol and composite midplane are increased, linear and quadratic increases in tunability result, respectively.

  11. Fractal Model for Acoustic Absorbing of Porous Fibrous Metal Materials

    Weihua Chen


    Full Text Available To investigate the changing rules between sound absorbing performance and geometrical parameters of porous fibrous metal materials (PFMMs, this paper presents a fractal acoustic model by incorporating the static flow resistivity based on Biot-Allard model. Static flow resistivity is essential for an accurate assessment of the acoustic performance of the PFMM. However, it is quite difficult to evaluate the static flow resistivity from the microstructure of the PFMM because of a large number of disordered pores. In order to overcome this difficulty, we firstly established a static flow resistivity formula for the PFMM based on fractal theory. Secondly, a fractal acoustic model was derived on the basis of the static flow resistivity formula. The sound absorption coefficients calculated by the presented acoustic model were validated by the values of Biot-Allard model and experimental data. Finally, the variation of the surface acoustic impedance, the complex wave number, and the sound absorption coefficient with the fractal dimensions were discussed. The research results can reveal the relationship between sound absorption and geometrical parameters and provide a basis for improving the sound absorption capability of the PFMMs.

  12. Ultrathin planar broadband absorber through effective medium design

    Dong Liu; Haitong Yu; Zhen Yang; Yuanyuan Duan


    Ultrathin planar absorbers hold promise in solar energy systems because they can reduce the material,fabrication,and system cost.Here,we present a general strategy of effective medium design to realize ultrathin planar broadband absorbers.The absorber consists of two ultrathin absorbing dielectrics to designan effective absorbing medium,a transparent layer,and metallic substrate.Compared with previous studies,this strategy provides another dimension of freedom to enhance optical absorption;therefore,destructive interference can be realized over a broad spectrum.To demonstrate the power and simplicity of this strategy,we both experimentally and theoretically characterized an absorber with 5-nm-thick Ge,10-nm-thick Ti,and 50-nm-thick SiO2 films coated on an Ag substrate fabricated using simple deposition methods.Absorptivity higher than 80% was achieved in 15-nm-thick (1/50 of the center wavelength) Ge and Ti films from 400 nm to near 1 μm.As an application example,we experimentally demonstrated that the absorber exhibited a normal solar absorptivity of 0.8 with a normal emittance of 0.1 at 500 ℃,thus demonstrating its potential in solar thermal systems.The effective medium design strategy is general and allows material versatility,suggesting possible applications in real-time optical manipulation using dynamic materials.

  13. The rat bowel of β-asaron absorbs the research

    QI Yue; JIA Dong; YOU Xian-min; ZOU Gui-xin; JIANG Hong


    Objective Study the β-asaron under the condition that the bowel each segment of rat and be worth in the diffent medicine density and pH of the absorption dynamics characteristic, as to it's the rat absorbs the part in the body and it absorbs the mechanism to carry on the study, for the further design β-asaron settle release the product to provide the living creature medicine learn the basis. Methods Apply the rat to the body to infuse to flow the bowel absorption experiment investigation and absorption dynamics characteristic;adopt the HPLC method measurement β-asaron is in rat body the bowel absorbs the medicine density within the reflux liquid. Results It absorb the quantity and β-asaron of the medicine in the reflux liquid, the density of β-asaron becomes the direct proption, the absorption speed constant of the medicine is basic and constant within the scope of the 19 μg·mL-1- 57 μg·mL-1; In the pH is 5.6; 6.9; 8.0 three kinds of dissimilarities lie the absorption velocity constant of the quality and absorb the of percentage and also did not show the difference of salience;β-asaron is in the small intestines the lower part absorb better, absorbthe velocity to press to return to bowel, ileum, jejunum, duodenum, colon to descend one by one in order, absorb the velocity constant one by one in order is 0.402, 0.396, 0.385, 0.325 h-1. Conclusions β-asaron absorbs to present a class absorption dynamics characteristic in the bowel way, absorbing the mechanism as passive absorption; in order to return to ileum and jejunums, main absorption part there is certain absorption in the colon, too.

  14. UV-visible absorbance spectroscopy as a proxy for peatland dissolved organic carbon (DOC) quantity and quality: considerations on wavelength and absorbance degradation.

    Peacock, Mike; Evans, Chris D; Fenner, Nathalie; Freeman, Chris; Gough, Rachel; Jones, Timothy G; Lebron, Inma


    Absorbance in the UV or visible spectrum (UV-vis) is commonly used as a proxy for DOC concentrations in waters draining upland catchments. To determine the appropriateness of different UV-vis measurements we used surface and pore water samples from two Welsh peatlands in four different experiments: (i) an assessment of single wavelength proxies (1 nm increments between 230-800 nm) for DOC concentration demonstrated that 254 nm was more accurate than 400 nm. The highest R(2) values between absorbance and DOC concentration were generated using 263 nm for one sample set (R(2) = 0.91), and 230 nm for the other three sample sets (respective R(2) values of 0.86, 0.81, and 0.93). (ii) A comparison of different DOC concentration proxies, including single wavelength proxies, a two wavelength model, a proxy using phenolic concentration, and a proxy using the area under a UV spectrum at 250-350 nm. It was found that both a single wavelength proxy (≤263 nm) and a two wavelength model performed well for both pore water and surface water. (iii) An evaluation of the E2 : E3, E2 : E4, E4 : E6 ratios, and SUVA (absorbance at 254 nm normalised to DOC concentration) as indicators of DOC quality showed that the E4 : E6 ratio was subject to extensive variation over time, and was highly correlated between surface water and pore water, suggesting that it is a useful metric to determine temporal changes in DOC quality. (iv) A repeated weekly analysis over twelve weeks showed no consistent change in UV-vis absorbance, and therefore an inferred lack of degradation of total DOC in samples that were filtered and stored in the dark at 4 °C.

  15. Towards Perfectly Absorbing Boundary Conditions for Euler Equations

    Hayder, M. Ehtesham; Hu, Fang Q.; Hussaini, M. Yousuff


    In this paper, we examine the effectiveness of absorbing layers as non-reflecting computational boundaries for the Euler equations. The absorbing-layer equations are simply obtained by splitting the governing equations in the coordinate directions and introducing absorption coefficients in each split equation. This methodology is similar to that used by Berenger for the numerical solutions of Maxwell's equations. Specifically, we apply this methodology to three physical problems shock-vortex interactions, a plane free shear flow and an axisymmetric jet- with emphasis on acoustic wave propagation. Our numerical results indicate that the use of absorbing layers effectively minimizes numerical reflection in all three problems considered.

  16. Simulation Process Analysis of Rubber Shock Absorber for Machine Tool

    Chai Rong Xia


    Full Text Available The simulation on rubber shock absorber of machine tool was studied. The simple material model of rubber was obtained by through the finite element analysis software ABAQUS. The compression speed and the hardness of rubber material were considered to obtain the deformation law of rubber shock absorber. The location of fatigue were confirmed from the simulation results. The results shown that the fatigue position is distributed in the corner of shock absorber. The degree of deformation is increased with increasing of compress speed, and the hardness of rubber material is proportional to deformation.

  17. Flexible subterahertz metamaterial absorber fabrication using inkjet printing technology

    Lee, Dongju; Sung, Hyuk-Kee; Lim, Sungjoon


    In this study, a flexible metamaterial (MM) absorber was designed at 0.1 THz and fabricated using inkjet printing technology. The unit cell of the MM absorber was designed using a finite element method-based full-wave simulation. The unit cell comprised square rings, and it was printed with silver nanoparticle ink on flexible Kapton polyimide film. The fabrication processes were performed using a material printer. The absorber's reflection coefficient was measured using a vector network analyzer and a WR-10 waveguide. The absorption ratio was 93.5 % at 0.102 THz. Therefore, we demonstrated the possibility of inkjet printing at a subterahertz band.

  18. Optimization of the acoustic absorption coefficients of certain functional absorbents

    Pocsa, V.; Biborosch, L.; Veres, A.; Halpert, E.; Lorian, R.; Botos, T.


    The sound absorption coefficients of some functional absorbents (mineral wool plates) are determined by the reverberation chamber method. The influence of the angle of inclination of the sound absorbing material with respect to the surface to be treated is analyzed as well as the influence of the covering index, defined as the ratio of the designed area of a plate and the area of the treated surface belonging to another plate. As compared with the conventional method of applying sound-absorbing plates, the analyzed structures have a higher technological and economical efficiency. The optimum structure corresponds to an angle of inclination of 15 deg and a covering index of 0.8.

  19. Energy deposition studies for the LBNE beam absorber

    Rakhno, Igor L; Tropin, Igor S


    Results of detailed Monte Carlo energy deposition studies performed for the LBNE absorber core and the surrounding shielding with the MARS15 code are described. The model of the entire facility, that includes a pion-production target, focusing horns, target chase, decay channel, hadron absorber system -- all with corresponding radiation shielding -- was developed using the recently implemented ROOT-based geometry option in the MARS15 code. This option provides substantial flexibility and automation when developing complex geometry models. Both normal operation and accidental conditions were studied. Various design options were considered, in particular the following: (i) filling the decay pipe with air or helium; (ii) the absorber mask material and shape; (iii) the beam spoiler material and size. Results of detailed thermal calculations with the ANSYS code helped to select the most viable absorber design options.

  20. [Decoloring and spectral properties analysis of innoxious ultraviolet absorbents].

    Fang, Yi-Wen; Ni, Wen-Xiu; Huang, Chong; Xue, Liang; Yu, Lin


    The ultraviolet absorbent extracted from mango leaves, was discolored by some decoloring agent. Then the spectral properties of the discolored ultraviolet absorbents were analyzed. The discolored method of ultraviolet absorbent was studied by comparing one with the others. The results showed that the discoloring effect was satisfactory by using active carbon, H2O2, citric acid, and oxalic acid as decoloring agent. Specially, when oxalic acid was used as decoloring agent, the color of the production was slight, the rate of production was high, and the absorption effect of ultraviolet ray was well. When the concentration of the ultraviolet absorbent solution is 0.5% (w/w), the ultraviolet ray transmission was smaller than 0.3% in 200-370 nm, and it increased slightly from 370 nm. There was a maximum value at 400 nm, approaching 12%.

  1. Integrated microcalorimeters using Ir TES and Sn mushroom absorbers

    Galeazzi, M. [Department of Physics, University of Miami, 1320 Campo Sano Dr., Coral Gables, FL 33146 (United States)]. E-mail:; Bogorin, D. [Department of Physics, University of Miami, 1320 Campo Sano Dr., Coral Gables, FL 33146 (United States); Chen, C. [Department of Physics, University of Miami, 1320 Campo Sano Dr., Coral Gables, FL 33146 (United States)


    University of Miami has recently started a program to fabricate fully integrated microcalorimeter arrays using iridium thin films as Transition Edge Sensors (TES) and tin mushroom absorbers. We present our preliminary results in both areas.

  2. Radio-absorbing properties of nickel-containing schungite powder

    Lyn'kov, L. M.; Borbot'ko, T. V.; Krishtopova, E. A.


    A nickel-containing shungite powder has been synthesized by means of chemical reduction from aqueous solutions. The chemical composition and radio-absorbing properties of this powder have been studied.

  3. Stretchable Metamaterial Absorber Using Liquid Metal-Filled Polydimethylsiloxane (PDMS

    Kyeongseob Kim


    Full Text Available A stretchable metamaterial absorber is proposed in this study. The stretchability was achieved by liquid metal and polydimethylsiloxane (PDMS. To inject liquid metal, microfluidic channels were fabricated using PDMS powers and microfluidic-channel frames, which were built using a three-dimensional printer. A top conductive pattern and ground plane were designed after considering the easy injection of liquid metal. The proposed metamaterial absorber comprises three layers of PDMS substrate. The top layer is for the top conductive pattern, and the bottom layer is for the meandered ground plane. Flat PDMS layers were inserted between the top and bottom PDMS layers. The measured absorptivity of the fabricated absorber was 97.8% at 18.5 GHz, and the absorption frequency increased from 18.5 to 18.65 GHz as the absorber was stretched from its original length (5.2 cm to 6.4 cm.

  4. Catalog of strong MgII absorbers (Lawther+, 2012)

    Lawther, D.; Paarup, Troels; Schmidt, Morten L.


    of our paper. A subset of the absorbers have been visually inspected - see the MAN_OK flag in the catalog. The number of sightlines searched, tabulated by absorber redshift, i.e. g(z), is available as an ASCII table (for S/N>8 and S/N>15). All analysis in our paper is based on the SNR>8 coverage......Here we present a catalog of strong (rest equivalent width Wr> intervening Mg II absorbers in the SDSS Data Release 7 quasar catalog (2010AJ....139.2360S, Cat. VII/260). The intervening absorbers were found by a semi-automatic algorithm written in IDL - for details of the algorithm see section 2...

  5. Experimental investigation of damping force of twin tube shock absorber

    Sandip K. Kadu


    Full Text Available A shock absorber is a mechanical device to damp shock impulse and convert kinetic energy into thermal energy. The damping effect of shock absorber depends on damping force and damping force is affected by various process parameters. In this analysis three process parameters damping diameter(A, number of holes(B and suspension velocity(C were considered and their effect on damping force of shock absorber was studied and accordingly suitable orthogonal array was selected by taguchi method. Experiment conducted on servo hydraulic testing machine and after conducting experiments damping force was measured and with the help of S/N ratio, ANOVA, Regression analysis optimum parameter values can be obtained and confirmation experiments was carried out. Twin tube shock absorber was used to carry out experimentation.

  6. Calculations in the Wheeler-Feynman Absorber Theory of Radiation.

    Balaji, Kalathur Sreenivasan

    One dimensional computer aided calculations were done to find the self-consistent solutions for various absorber configurations in the context of the Wheeler-Feynman Absorber theory, wherein every accelerating charge is assumed to produce a time symmetric combination of advanced and retarded fields. These calculations picked out the so called "outerface" solution for incomplete absorbers and showed that advanced as well as retarded signals interact with matter in the same manner as in the full retarded theory. Based on these calculations the Partridge experiment and the Schmidt-Newman experiment were ruled out as tests of the Absorber theory. An experiment designed to produce and detect advanced effects is proposed, based on more one-dimensional calculations.

  7. Calculations in the Wheeler-Feynman absorber theory of radiation

    Balaji, K.S.


    One dimensional computer aided calculations were done to find the self consistent solutions for various absorber configurations in the context of the Wheeler-Feynman absorber theory, wherein every accelerating charge is assumed to produce a time symmetric combination of advanced and retarded fields. These calculations picked out the so called outerface solution for incomplete absorbers and showed that advanced as well as retarded signals interact with matter in the same manner as in the full retarded theory. Based on these calculations, the Partridge experiment and the Schmidt-Newman experiment were ruled out as tests of the absorber theory. An experiment designed to produce and detect advanced effects is proposed, based on more one-dimensional calculations.

  8. Angular solar absorptance of absorbers used in solar thermal collectors.

    Tesfamichael, T; Wäckelgård, E


    The optical characterization of solar absorbers for thermal solar collectors is usually performed by measurement of the spectral reflectance at near-normal angle of incidence and calculation of the solar absorptance from the measured reflectance. The solar absorptance is, however, a function of the angle of incidence of the light impinging on the absorber. The total reflectance of two types of commercial solar-selective absorbers, nickel-pigmented anodized aluminum, and sputtered nickel nickel oxide coated aluminum are measured at angles of incidence from 5 to 80 in the wavelength range 300-2500 nm by use of an integrating sphere. From these measurements the angular integrated solar absorptance is determined. Experimental data are compared with theoretical calculations, and it is found that optical thin-film interference effects can explain the significant difference in solar absorptance at higher angles for the two types of absorbers.

  9. Two-dimensional QR-coded metamaterial absorber

    Sui, Sai; Ma, Hua; Wang, Jiafu; Pang, Yongqiang; Zhang, Jieqiu; Qu, Shaobo


    In this paper, the design of metamaterial absorbers is proposed based on QR coding and topology optimization. Such absorbers look like QR codes and can be recognized by decoding softwares as well as mobile phones. To verify the design, two lightweight wideband absorbers are designed, which can achieve wideband absorption above 90 % in 6.68-19.30 and 7.00-19.70 GHz, respectively. More importantly, polarization-independent absorption over 90 % can be maintained under incident angle within 55°. The QR code absorber not only can achieve wideband absorption, but also can carry information such as texts and Web sites. They are of important values in applications such identification and electromagnetic protection.

  10. Liquid absorbent solutions for separating nitrogen from natural gas

    Friesen, Dwayne T.; Babcock, Walter C.; Edlund, David J.; Lyon, David K.; Miller, Warren K.


    Nitrogen-absorbing and -desorbing compositions, novel ligands and transition metal complexes, and methods of using the same, which are useful for the selective separation of nitrogen from other gases, especially natural gas.

  11. Distribution of Doppler Redshifts of Associated Absorbers of SDSS Quasars

    Cai-Juan Pan; Zhi-Fu Chen


    Doppler redshifts of a sample of Mg II associated absorbers of SDSS DR7 quasars are analysed. We find that there might be three Gaussian components in the distribution of the Doppler redshift. The first Gaussian component, with the peak being located at Dopp = -0.0074, probably arises from absorbers with outflow histories observed in the direction close to jets of quasars. The second Gaussian component, with the peak being located at Dopp = -0.0017, possibly arises from absorbers with outflow histories observed in the direction far away from jets of quasars. Whereas, the third Gaussian component, with the peak being located at Dopp = -0.0004, might arise from the random motion of absorbers with respect to quasars.

  12. Evaluation of electromagnetic absorbing capacity of materials in foundry industry

    D. Nowak


    Full Text Available In the paper, a research on determining the standing wave ratio as a measure of electromagnetic absorbing capacity of moulding materials is presented. Preliminary tests performed using a microwave strip line showed that high-silica, chromite and magnesite moulding sands are characterised by low absorbing capacity of microwaves. It was demonstrated that microwave absorbing capacity is significantly affected by chemical compounds included in the examined substrates. It was found that use of a microwave strip line permits precise determining characteristic microwave absorbing capacities of various moulding materials and thus their suitability for microwave drying/hardening of moulds and cores or for other foundry processes. Such a microwave drier can be applied for identifying mass components and for determining e.g. base granularity by means of precisely determined reflection ratios |Γ| and positions of minimum signal values.

  13. 21 CFR 878.4830 - Absorbable surgical gut suture.


    ... (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4830 Absorbable...) or the submucosal fibrous tissue of sheep (ovine) intestine, and is intended for use in soft...

  14. Multi-band metamaterial absorber topology for infrared frequency regime

    Mulla, Batuhan; Sabah, Cumali


    In this paper, a new multiband metamaterial absorber design is proposed and the numerical characterization is carried out. The design is composed of three layers with differently sized quadruplets in which the interaction among them causes the multiband absorption response in the infrared frequency regime. In order to characterize the absorber and explain the multiband topology, some parametric studies with respect to the dimensions of the structure are carried out and the contributions of the quadruplets to the absorption spectrum are analyzed. According to the results, it is found that the proposed metamaterial absorber has five bands in the infrared frequency regime with the absorption levels of: 98.90%, 99.39%, 86.46%, 92.80% and 97.96%. Moreover, the polarization dependency of the structure is examined and it is found that the design operates well as a perfect absorber with polarization independency in the studied frequency range.

  15. Wheeler-Feynman Absorbers on the Light Horizon

    Lear, C W


    Early Wheeler-Feynman absorber theories invoke both retarded and advanced electromagnetic waves for photon emission and absorption in order to remove problems involving lack of radiative damping during electron acceleration. Subsequent inquiries have suggested that only certain cosmologies would allow such a retarded-advanced wave mechanism to exist. These include quasi-steady state cosmologies and exclude flat, expanding Friedman-type cosmologies. Key to the exclusion process is a diminishing density of future absorbers in an ever-expanding universe. Such absorbers would be expected to be real electromagnetically interacting particles. However future virtual absorber sites, if they exist, would not be so diminished. Such sites would be plentiful on the future light horizon, receding from the source at the speed of light. The present treatment proposes that virtual absorption sites are present at every point in spacetime, and are characterized by the Fresnel-Kirchhoff diffraction integral. On the future light...

  16. Phase transition analogies in a laser with saturable absorber

    Dembinski, S.T.; Kossakowski, A. (Uniwersytet Mikolaja Kopernika, Torun (Poland). Instytut Fizyki)


    The possible threshold behavior of a four-level laser in the presence of a saturable absorber is examined. In the parameter space of the absorber, regions where the threshold behavior resemble first or second order phase transitions are found. The analysis is based on the semi-classical approximation and makes use of some concepts taken from Thom's theory of catastrophes.

  17. Calirimeter/absorber optimization for a RHIC dimuon experiment

    Aronson, S.H.; Murtagh, M.J.; Starks, M. [Brookhaven National Lab., Upton, NY (United States); Liu, X.T.; Petitt, G.A.; Zhang, Z. [Georgia State Univ., Atlanta (United States); Ewell, L.A.; Hill, J.C.; Wohn, F.K. [Iowa State Univ., Ames (United States); Costales, J.B.; Namboodiri, M.N., Sangster, T.C.; Thomas, J.H. [Lawrence Livermore National Lab., CA (United States); Gavron, A.; Waters, L. [Los Alamos National Lab., NM (United States); Kehoe, W.L.; Steadman, S.G. [Massachusetts Institute of Technology, Cambridge (United States); Awes, T.C.; Obenshain, F.E.; Saini, S.; Young, G.R. [Oak Ridge National Lab., TN (United States); Chang, J.; Fung, S.Y.; Kang, J.H. [Univ. of California, Riverside, CA (United States); Kreke, J.; He, Xiaochun, Sorensen, S.P. [Univ. of Tennessee, Knoxville (United States); Cornell, E.C.; Maguire, C.F. [Vanderbilt Univ., Nashville, TN (United States)


    The RD-10 R&D effort on calorimeter/absorber optimization for a RHIC experiment had an extended run in 1991 using the A2 test beam at the AGS. Measurements were made of the leakage of particles behind various model hadron calorimeters. Behavior of the calorimeter/absorber as a muon-identifier was studied. First comparisons of results from test measurements to calculated results using the GHEISHA code were made

  18. Calirimeter/absorber optimization for a RHIC dimuon experiment

    Aronson, S.H.; Murtagh, M.J.; Starks, M. [Brookhaven National Lab., Upton, NY (United States); Liu, X.T.; Petitt, G.A.; Zhang, Z. [Georgia State Univ., Atlanta (United States); Ewell, L.A.; Hill, J.C.; Wohn, F.K. [Iowa State Univ., Ames (United States); Costales, J.B.; Namboodiri, M.N., Sangster, T.C.; Thomas, J.H. [Lawrence Livermore National Lab., CA (United States); Gavron, A.; Waters, L. [Los Alamos National Lab., NM (United States); Kehoe, W.L.; Steadman, S.G. [Massachusetts Institute of Technology, Cambridge (United States); Awes, T.C.; Obenshain, F.E.; Saini, S.; Young, G.R. [Oak Ridge National Lab., TN (United States); Chang, J.; Fung, S.Y.; Kang, J.H. [Univ. of California, Riverside, CA (United States); Kreke, J.; He, Xiaochun, Sorensen, S.P. [Univ. of Tennessee, Knoxville (United States); Cornell, E.C.; Maguire, C.F. [Vanderbilt Univ., Nashville, TN (United States)


    The RD-10 R&D effort on calorimeter/absorber optimization for a RHIC experiment had an extended run in 1991 using the A2 test beam at the AGS. Measurements were made of the leakage of particles behind various model hadron calorimeters. Behavior of the calorimeter/absorber as a muon-identifier was studied. First comparisons of results from test measurements to calculated results using the GHEISHA code were made

  19. Design of integration-ready metasurface-based infrared absorbers

    Ogando, Karim, E-mail:; Pastoriza, Hernán [Laboratorio de Bajas Temperaturas, Instituto Balseiro and Centro Atómico Bariloche, Bariloche 8400 (Argentina)


    We introduce an integration ready design of metamaterial infrared absorber, highly compatible with many kinds of fabrication processes. We present the results of an exhaustive experimental characterization, including an analysis of the effects of single meta-atom geometrical parameters and collective arrangement. We confront the results with the theoretical interpretations proposed in the literature. Based on the results, we develop a set of practical design rules for metamaterial absorbers in the infrared region.

  20. On the fluid-loaded thin-panel absorbers

    TONG Xiaopeng; BAI Guofeng; LIU Ke; TIAN Jing


    The sound absorption of fluid-loaded thin-panel absorbers was investigated. A general theory and an approximate theory are given. Parameters of potential energy kinetic energy, and the fluid-loading factor are proposed. This has made the absorption mechanism clearer, and the computation simpler than before. The absorption coefficients and impedances of thin-panel absorbers were tested with a hydro-acoustical tube. The experimental results agreed well with the theoretical results.

  1. A novel composite sound absorber with recycled rubber particles

    Hong, Zhou; Bo, Li; Guangsu, Huang; Jia, He


    A new kind of composite sound absorber has been fabricated, using recycled rubber particles with good attenuation property as sound energy attenuation layer, low characteristic impedance materials such as polymer porous foam or perforated panel as matching layer. Its' attractive characteristics include: low-cost, broad-band sound absorption, thin in thickness and relatively simple processing. An acoustic transmission analytical model is developed and successfully applied to evaluate the sound absorption of the composite absorber.

  2. Electron paramagnetic resonance measurements of absorbed dose in teeth from citizens of Ozyorsk

    Wieser, A.; Semiochkina, N. [Helmholtz Zentrum Muenchen - German Research Center for Environmental Health, Institute of Radiation Protection, Neuherberg (Germany); Vasilenko, E.; Aladova, E.; Smetanin, M. [Southern Urals Biophysics Institute, Ozyorsk (Russian Federation); Fattibene, P. [Istituto Superiore di Sanita, Rome (Italy)


    In 1945, within the frame of the Uranium Project for the production of nuclear weapons, the Mayak nuclear facilities were constructed at the Lake Irtyash in the Southern Urals, Russia. The nuclear workers of the Mayak Production Association (MPA), who lived in the city of Ozyorsk, are the focus of epidemiological studies for the assessment of health risks due to protracted exposure to ionising radiation. Electron paramagnetic resonance measurements of absorbed dose in tooth enamel have already been used in the past, in an effort to validate occupational external doses that were evaluated in the Mayak Worker Dosimetry System. In the present study, 229 teeth of Ozyorsk citizens not employed at MPA were investigated for the assessment of external background exposure in Ozyorsk. The annually absorbed dose in tooth enamel from natural background radiation was estimated to be (0.7 ± 0.3) mGy. For citizens living in Ozyorsk during the time of routine noble gas releases of the MPA, which peaked in 1953, the average excess absorbed dose in enamel above natural background was (36 ± 29) mGy, which is consistent with the gamma dose obtained by model calculations. In addition, there were indications of possible accidental gaseous MPA releases that affected the population of Ozyorsk, during the early and late MPA operation periods, before 1951 and after 1960. (orig.)


    I. Glagolenko; D. Wachs; N. Woolstenhulme; G. Chang; B. Rabin; C. Clark; T. Wiencek


    Based on the results of the reactor physics assessment, conversion of the Advanced Test Reactor (ATR) at the Idaho National Laboratory (INL) can be potentially accomplished in two ways, by either using U-10Mo monolithic or U-7Mo dispersion type plates in the ATR fuel element. Both designs, however, would require incorporation of the burnable absorber in several plates of the fuel element to compensate for the excess reactivity and to flatten the radial power profile. Several different types of burnable absorbers were considered initially, but only borated compounds, such as B4C, ZrB2 and Al-B alloys, were selected for testing primarily due to the length of the ATR fuel cycle and fuel manufacturing constraints. To assess and compare irradiation performance of the U-Mo fuels with different burnable absorbers we have designed and manufactured 28 RERTR miniplates (20 fueled and 8 non-fueled) containing fore-mentioned borated compounds. These miniplates will be tested in the ATR as part of the RERTR-13 experiment, which is described in this paper. Detailed plate design, compositions and irradiations conditions are discussed.

  4. Safety and performance of the second-generation drug-eluting absorbable metal scaffold in patients with de-novo coronary artery lesions (BIOSOLVE-II): 6 month results of a prospective, multicentre, non-randomised, first-in-man trial

    Haude, Michael; Ince, Hüseyin; Abizaid, Alexandre; Toelg, Ralph; Lemos, Pedro Alves; von Birgelen, Clemens; Christiansen, Evald Høj; Wijns, William; Neumann, Franz-Josef; Kaiser, Christoph; Eeckhout, Eric; Lim, Soo Teik; Escaned, Javier; Garcia-Garcia, Hector M.; Waksman, Ron


    Background Absorbable scaffolds were designed to overcome the limitations of conventional, non-absorbable metal-based drug-eluting stents. So far, only polymeric absorbable scaffolds are commercially available. We aimed to assess the safety and performance of a novel second-generation drug-eluting

  5. Contribution of recoil atoms to irradiation damage in absorber materials

    Simeone, D.; Hablot, O.; Micalet, V.; Bellon, P.; Serruys, Y.


    Absorbing materials are used to control the reactivity of nuclear reactors by taking advantage of nuclear reactions (e.g., 10B(n,α) 7Li) where neutrons are absorbed. During such reactions, energetic recoils are produced. As a result, radiation damage in absorbing materials originates both from these nuclear reactions and from elastic collisions between neutrons and atoms. This damage eventually leads to a partial destruction of the materials, and this is the main limitation on their lifetime in nuclear reactors. Using a formalism developed to calculate displacements per atoms (dpa) in a multi atomic target, we have calculated damages in terms of displacements per atom in a (n,α) absorbing material taking into account geometrical effects of 10 boron self shielding and transmutation reactions induced by neutrons inside the absorber. Radiation damage is calculated for boron carbide and hafnium diboride ceramics in a Pressurized Water Reactor environment. It is shown that recoils produced by nuclear reactions account for the main part of the radiation damage created in these ceramics. Damages are calculated as a function of the distance from the center of an absorber pellet. Due to the self-shielding effect, these damage curves exhibit sharp maxima, the position of which changes in time.

  6. Wideband-Switchable Metamaterial Absorber Using Injected Liquid Metal

    Kim, Hyung Ki; Lee, Dongju; Lim, Sungjoon


    Metamaterial absorbers can provide good solutions for radar-cross-section (RCS) reduction. In spite of their attractive features of thinness, lightness, and low cost, resonant metamaterial absorbers have a drawback of narrow bandwidth. For practical radar applications, wideband absorbers are necessary. In this paper, we propose a wideband-switchable metamaterial absorber using liquid metal. In order to reduce RCS both for X-band and C-band, the switchable Jerusalem cross (JC) resonator is introduced. The JC resonator consists of slotted circular rings, chip resistors, and microfluidic channels. The JC resonator is etched on a flexible printed circuit board (FPCB), and the microfluidic channels are laser-etched on a polydimethylsiloxane (PDMS) material. The proposed absorber can switch the absorption frequency band by injecting a liquid metal alloy into the channels. The performance of the absorber was demonstrated through full-wave simulation and through measurements employing prototypes. The experimental results showed absorption ratios of over 90% from 7.43 GHz to 14.34 GHz, and from 5.62 GHz to 7.3 GHz, with empty channels and liquid metal-filled channels, respectively. Therefore, the absorption band was successfully switched between the C-band (4–8 GHz) and the X-band (8–12 GHz) by injecting liquid metal eutectic gallium indium alloy (EGaIn) into the channels. PMID:27546310

  7. Thin Perfect Absorbers for Electromagnetic Waves: Theory, Design, and Realizations

    Ra'di, Y.; Simovski, C. R.; Tretyakov, S. A.


    With recent advances in nanophotonics and nanofabrication, considerable progress has been achieved in realizations of thin composite layers designed for full absorption of incident electromagnetic radiation, from microwaves to the visible. If the layer is structured at a subwavelength scale, thin perfect absorbers are usually called "metamaterial absorbers," because these composite structures are designed to emulate some material responses not reachable with any natural material. On the other hand, many thin absorbing composite layers were designed and used already in the time of the introduction of radar technology, predominantly as a means to reduce radar visibility of targets. In view of a wide variety of classical and new topologies of optically thin metamaterial absorbers and plurality of applications, there is a need for a general, conceptual overview of the fundamental mechanisms of full absorption of light or microwave radiation in thin layers. Here, we present such an overview in the form of a general theory of thin perfectly absorbing layers. Possible topologies of perfect metamaterial absorbers are classified based on their fundamental operational principles. For each of the identified classes, we provide design equations and give examples of particular realizations. The concluding section provides a summary and gives an outlook on future developments in this field.

  8. Investigations on laser transmission welding of absorber-free thermoplastics

    Mamuschkin, Viktor; Olowinsky, Alexander; Britten, Simon W.; Engelmann, Christoph


    Within the plastic industry laser transmission welding ranks among the most important joining techniques and opens up new application areas continuously. So far, a big disadvantage of the process was the fact that the joining partners need different optical properties. Since thermoplastics are transparent for the radiation of conventional beam sources (800- 1100 nm) the absorbance of one of the joining partners has to be enhanced by adding an infrared absorber (IR-absorber). Until recently, welding of absorber-free parts has not been possible. New diode lasers provide a broad variety of wavelengths which allows exploiting intrinsic absorption bands of thermoplastics. The use of a proper wavelength in combination with special optics enables laser welding of two optically identical polymer parts without absorbers which can be utilized in a large number of applications primarily in the medical and food industry, where the use of absorbers usually entails costly and time-consuming authorization processes. In this paper some aspects of the process are considered as the influence of the focal position, which is crucial when both joining partners have equal optical properties. After a theoretical consideration, an evaluation is carried out based on welding trials with polycarbonate (PC). Further aspects such as gap bridging capability and the influence of thickness of the upper joining partner are investigated as well.

  9. Ammonia-water absorption in vertical tubular absorbers

    Fernandez-Seara, Jose; Sieres, Jaime; Rodriguez, Cristobal; Vazquez, Manuel [Area de Maquinas y Motores Termicos, Escuela Tecnica Superior de Ingenieros Industriales, Campus Lagoas-Marcosende, No 9, 36200 Vigo (Spain)


    This paper presents a detailed analysis of the heat and mass transfer processes during the absorption of ammonia into water in a co-current vertical tubular absorber. The absorber configuration is of the shell and tubes type. The absorption process progresses as the vapour and liquid contact inside the tubes. Water is used as the absorber cooling medium. A differential mathematical model has been developed on the basis of mass and energy balances and heat and mass transfer equations, in order to provide further understanding of the absorber behaviour. The model takes into account separately for the churn, slug and bubbly flow patterns experimentally forecasted in this type of absorption processes inside vertical tubes and considers the simultaneous heat and mass transfer processes in both liquid and vapour phases, as well as heat transfer to the cooling medium. The model equations have been solved using the finite-difference method. Results obtained for specific data are depicted to show local values of the most important variables all along the absorber length. Parametric analyses have been performed to show the influence of design parameters and operating conditions on the absorber performance. The effect of the heat and mass transfer coefficients has also been evaluated. (authors)

  10. Design Guidelines for Ferrite Absorbers Submitted to RF-induced Heating

    Bertarelli, A


    The use of ferrite absorbers is one of the most effective means of damping potentially harmful high order RF modes, which may lead to beam instabilities and excessive power losses in accelerator devices. However, the power deposited on ferrite absorbers themselves maylead to ferrite exceeding its Curie temperature, losing its damping properties. An evaluation of the ferrite capability to dissipate deposited heat is hence of paramount importance for the safe design of particle accelerator devices. In this paper, figures of merit are proposed to assess the maximum specific power allowed on a generic ferrite tile, before it reaches its Curie temperature. Due to its inherent brittleness, sufficient contact pressure between ferrite and its housing, allowing heat transmission by conduction, can hardly be applied. A semi-analytical study is thus performed, assuming that ferrite is evacuating heat solely through radiation. The described method is then exemplified in the case of the BPM-embedded tertiary collimator (T...

  11. Evaluation of bismuth shielding effectiveness in reducing breast absorbed dose during thoracic CT scan

    Alonso, T. C.; Mourao, A. P.; Santana, P. C.; Silva, T. A. [Federal University of Minas Gerais, Program of Nuclear Science and Techniques, Av. Pte. Antonio Carlos 6627, 31270-901 Belo Horizonte, Minas Gerais (Brazil)


    Computed Tomography (CT) is an essential method for tracking neoplasia and efficiently diagnosing a wide variety of thoracic diseases. CT is generally considered the most accurate choice for lung examination. Due to the growing use of CT, breast and other superficial and radiosensitive organs are unnecessarily irradiated during radiological procedures, thus requiring the development of strategies appropriate to optimize and, if possible, to reduce the radiation dose. The use of bismuth shielding to reduce radiation dose absorbed by breast during thoracic CT examinations has been the subject of many studies recently published by Brazilian and foreign authors of various fields. The purpose of this paper is both to accurately determine the glandular dose when breast is exposed to radiation and to assess the reduction in absorbed dose during thoracic CT examinations, using a set of Thermoluminescent Dosimeters, an anthropomorphic phantom and bismuth shielding. (Author)

  12. ECG movement artefacts can be greatly reduced with the aid of a movement absorbing device

    Harrison, Adrian Paul; Wandall, Kirsten; Thorball, Jørgen


    Accurate ECG signal analysis can be confounded by electric lead, and/or electrode movements varying in origin from, for example, hiccups, tremor or patient restlessness. ECG signals recorded using either a conventional electrode holder or with the aid of an electrode holder capable of absorbing...... movement artefacts, were measured on a healthy human subject. Results show a greatly improved stability of the ECG signal recorded using an electrode holder capable of absorbing movement artefacts during periods of lead disturbance, and highlight the movement artefacts that develop when the recording lead...... of a conventional ECG electrode holder is tugged or pulled during theperiod of monitoring. It is concluded that the new design of ECG electrode holder will not only enable clearer signal recordings for clinical assessment, but will reduce the ECG artefacts associated with the transportation of patients, and may...

  13. Propionate absorbed from the colon acts as gluconeogenic substrate in a strict carnivore, the domestic cat (Felis catus)

    Verbrugghe, A; Hesta, M; Daminet, S


    In six normal-weight and six obese cats, the metabolic effect of propionate absorbed from the colon was assessed. Two colonic infusions were tested in a crossover design with intervals of 4 weeks. The test solution contained 4 mmol sodium propionate per kg ideal body weight in a 0.2% NaCl solution...

  14. Pilot in vivo study of an absorbable polydioxanone vena cava filter.

    Eggers, Mitchell D; McArthur, Mark J; Figueira, Tomas A; Abdelsalam, Mohamed E; Dixon, Katherine P; Pageon, Laura R; Wallace, Michael J; Huang, Steven Y


    The objectives of this study were to evaluate tensile strength retention of polydioxanone as a function of time in a swine venous system and to assess the feasibility of an absorbable inferior vena cava (IVC) filter made from polydioxanone in a pilot swine study. Twenty strands (60 cm each) of size 1 polydioxanone absorbable suture (Ethicon, Somerville, NJ) were placed in the central venous system of domestic swine. Strands were harvested at weekly intervals during 10 weeks for tensile strength testing. Results were compared with control samples obtained from an in vitro engineered circulation system containing sodium phosphate buffer solution. Three IVC filters braided from polydioxanone suture were also catheter deployed in three swine to assess absorbable IVC filter feasibility. Polydioxanone retained 82% tensile strength in vitro vs 79% in vivo at 35 days (P > .22), the desired prophylactic duration. For IVC filters made from polydioxanone, technical success of placement was achieved in all three filters deployed (100%). Autologous thrombus deployed inferior to the filter remained trapped in the filter until thrombus resorption, with no evidence of pulmonary emboli on follow-up computed tomography. There were no instances of caval penetration, filter-induced IVC thrombosis, filter migration, or tilt >15 degrees with imaging and clinical follow-up carried out to 32 weeks. Strength retention of polydioxanone suture placed in the venous system of swine is similar to earlier in vitro studies out to 10 weeks (P > .06 for all weeks) and is more than sufficient (8.20 ± 0.37 kg mean load at break for size 1) to trap thrombus. Pilot animal study suggests that an absorbable polydioxanone IVC filter can be catheter deployed to capture and to hold iatrogenically administered autologous thrombus through resorption. Copyright © 2015 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

  15. Systematic review of absorbable vs non-absorbable sutures used for the closure of surgical incisions

    Muhammad; S; Sajid; Malcolm; R; Mc; Fall; Pauline; A; Whitehouse; Parv; S; Sains


    AIM: To report a systematic review of published randomized controlled trials(RCTs) investigating the role of absorbable suture(AS) against non-AS(NAS) used for the closure of surgical incisions.METHODS: RCTs investigating the use of AS vs NAS for the closure of surgical incisions were statistically analysed based upon the principles of meta-analysis and the summated outcomes were represented as OR.RESULTS: The systematic search of medical literature yielded 10 RCTs on 1354 patients. Prevalence of wound infection(OR = 0.97; 95%CI: 0.56, 1.69; Z = 0.11; P = 0.92) and operative morbidity(P = 0.45) was comparable in both groups. Nonetheless, the use of AS lead to lower risk of wound break-down(OR = 0.12; 95%CI: 0.04, 0.39; Z = 3.52; P < 0.0004).CONCLUSION: This meta-analysis of 10 RCTs demonstrates that the use of AS is similar to NAS for skin closure for surgical site infection and other operative morbidities. AS do not increase the risk of skin wound dehiscence,rather lead to a reduced risk of wound dehiscence compared to NAS.

  16. Highly selective etching of SnO2 absorber in binary mask structure for extreme ultra-violet lithography.

    Lee, Soo Jin; Jung, Chang Yong; Park, Sung Jin; Hwangbo, Chang Kweun; Seo, Hwan Seok; Kim, Sung Soo; Lee, Nae-Eung


    Among the core EUVL (extreme ultra-violet lithography) technologies for nanoscale patterning below the 30 nm node for Si chip manufacturing, new materials and fabrication processes for high-performance EUVL masks are of considerable importance due to the use of new reflective optics. In this work, the selective etching of SnO2 (tin oxide) as a new absorber material, with high EUV absorbance due to its large extinction coefficient, for the binary mask structure of SnO2 (absorber layer)/Ru (capping/etch stop layer)/Mo-Si multilayer (reflective layer)/Si (substrate), was investigated. Because infinitely high selectivity of the SnO2 layer to the Ru ESL is required due to the ultrathin nature of the Ru layer, various etch parameters were assessed in the inductively coupled Cl2/Ar plasmas in order to find the process window required for infinitely high etch selectivity of the SnO2 layer. The results showed that the gas flow ratio and V(dc) value play an important role in determining the process window for the infinitely high etch selectivity of SnO2 to Ru ESL. The high EUV-absorbance SnO2 layer, patternable by a dry process, allows a smaller absorber thickness, which can mitigate the geometric shadowing effects observed for high-performance binary EUVL masks.

  17. Metamaterial Absorber for Electromagnetic Waves in Periodic Water Droplets

    Yoo, Young Joon; Ju, Sanghyun; Park, Sang Yoon; Ju Kim, Young; Bong, Jihye; Lim, Taekyung; Kim, Ki Won; Rhee, Joo Yull; Lee, Youngpak


    Perfect metamaterial absorber (PMA) can intercept electromagnetic wave harmful for body in Wi-Fi, cell phones and home appliances that we are daily using and provide stealth function that military fighter, tank and warship can avoid radar detection. We reported new concept of water droplet-based PMA absorbing perfectly electromagnetic wave with water, an eco-friendly material which is very plentiful on the earth. If arranging water droplets with particular height and diameter on material surface through the wettability of material surface, meta-properties absorbing electromagnetic wave perfectly in GHz wide-band were shown. It was possible to control absorption ratio and absorption wavelength band of electromagnetic wave according to the shape of water droplet-height and diameter- and apply to various flexible and/or transparent substrates such as plastic, glass and paper. In addition, this research examined how electromagnetic wave can be well absorbed in water droplets with low electrical conductivity unlike metal-based metamaterials inquiring highly electrical conductivity. Those results are judged to lead broad applications to variously civilian and military products in the future by providing perfect absorber of broadband in all products including transparent and bendable materials.

  18. Are bio-absorbable stents the future of SFA treatment?

    Peeters, P; Keirse, K; Verbist, J; Deloose, K; Bosiers, M


    Several limitations inherent to the implantation of a metallic device, such as the occurrence of in-stent re-stenosis, in an arterial lumen intuitively explain the interest for developing bio-absorbable stents. Two main types of bio-absorbable stents currently exist: polymer stents and metallic stents. To date, no studies with bio-absorbable stents have been conducted in the superficial femoral artery (SFA). Because of their strut thickness and lack of radial force, polymer stents are no good candidates for endovascular use. Absorbable metal stents (AMS) do have the potential to perform well for artery treatment, although current evidence from in-human coronary and infrapopliteal studies yield unsatisfactory results. Drastic technological improvements are mandatory before AMS can be considered for every day practice. Yet, it is our belief that further development of other metal and non-metal bio-absorbable stents, with or without drug-coating, may lead to the creation of the ultimate SFA stent.

  19. Advanced UV Absorbers for the Protection of Human Skin.

    Hüglin, Dietmar

    The increasing awareness of the damaging effects of UV radiation to human skin triggered the market introduction of new cosmetic UV absorbers. This article summarizes the outcome of a multi-year research program, in which the author contributed to the development of different new UV filters. First of all, the molecular design and the basic properties of bis-ethylhexyloxyphenol methoxyphenyl triazine (BEMT) will be presented. This oil-soluble filter, which today is widely used in both beach products and skin care products, exhibits inherent photostability and strong broad-spectrum UV-A+B absorbance. Based on the concept of micronized organic UV absorbers, the UV-B filter tris biphenyl triazine (TBPT) will be introduced. At present TBPT exhibits the highest efficacy of all cosmetic UV absorbers in the market (measured by area under the UV spectrum). Finally, the concept of liposomogenic UV absorbers will be featured. This approach was developed to create water-resistant UV filters, as liposomogenic structures are thought to integrate into the lipids of the horny layer. Due to prohibitively high costs, this technology did not result in a commercial product so far.

  20. Metamaterial Absorber for Electromagnetic Waves in Periodic Water Droplets.

    Yoo, Young Joon; Ju, Sanghyun; Park, Sang Yoon; Ju Kim, Young; Bong, Jihye; Lim, Taekyung; Kim, Ki Won; Rhee, Joo Yull; Lee, YoungPak


    Perfect metamaterial absorber (PMA) can intercept electromagnetic wave harmful for body in Wi-Fi, cell phones and home appliances that we are daily using and provide stealth function that military fighter, tank and warship can avoid radar detection. We reported new concept of water droplet-based PMA absorbing perfectly electromagnetic wave with water, an eco-friendly material which is very plentiful on the earth. If arranging water droplets with particular height and diameter on material surface through the wettability of material surface, meta-properties absorbing electromagnetic wave perfectly in GHz wide-band were shown. It was possible to control absorption ratio and absorption wavelength band of electromagnetic wave according to the shape of water droplet-height and diameter- and apply to various flexible and/or transparent substrates such as plastic, glass and paper. In addition, this research examined how electromagnetic wave can be well absorbed in water droplets with low electrical conductivity unlike metal-based metamaterials inquiring highly electrical conductivity. Those results are judged to lead broad applications to variously civilian and military products in the future by providing perfect absorber of broadband in all products including transparent and bendable materials.

  1. Absorbing Set Spectrum Approach for Practical Code Design

    Wang, Jiadong; Zhang, Zhengya; Wesel, Richard


    This paper focuses on controlling the absorbing set spectrum for a class of regular LDPC codes known as separable, circulant-based (SCB) codes. For a specified circulant matrix, SCB codes all share a common mother matrix, examples of which are array-based LDPC codes and many common quasi-cyclic codes. SCB codes retain the standard properties of quasi-cyclic LDPC codes such as girth, code structure, and compatibility with efficient decoder implementations. In this paper, we define a cycle consistency matrix (CCM) for each absorbing set of interest in an SCB LDPC code. For an absorbing set to be present in an SCB LDPC code, the associated CCM must not be full columnrank. Our approach selects rows and columns from the SCB mother matrix to systematically eliminate dominant absorbing sets by forcing the associated CCMs to be full column-rank. We use the CCM approach to select rows from the SCB mother matrix to design SCB codes of column weight 5 that avoid all low-weight absorbing sets (4, 8), (5, 9), and (6, 8). ...

  2. Frequency-tunable terahertz absorbers based on graphene metasurface

    Chen, Ming; Sun, Wei; Cai, Jianjin; Chang, Linzi; Xiao, Xiaofei


    We present efficient designs of graphene-based thin absorbers, which are capable of near-unity absorption of the incident electromagnetic waves in the terahertz regime. Primarily, a single-frequency absorber is proposed. Subsequently, by simply stacking the double layer graphene metasurface with various geometric dimensions, the dual-frequency absorption and broadband absorption are realized respectively. Results demonstrate that the absorptivity of the single-frequency absorber reaches 99.51% at 2.71 THz when the Fermi energy is fixed at 0.9 eV. The dual-frequency absorber can simultaneously work at two frequencies with its absorptivity being 98.94% for 1.99 THz and 99.1% for 2.69 THz. The bandwidth of absorption rate above 90% expands three times when compared with the former single-frequency absorber. Additionally, it possesses the polarization-insensitive and large angle tolerance properties. More importantly, the absorption frequency can be dynamically controlled by adjusting Fermi energy levels without varying the nanostructure, which exhibits tremendous application values in many fields.

  3. Optimally tuned vibration absorbers to control sound transmission

    Grissom, Michael; Belegundu, Ashok; Koopmann, Gary


    A design optimization method is proposed for controlling broadband vibration of a structure and it concomitant acoustic radiation using multiple-tuned absorbers. A computationally efficient model of a structure is developed and coupled with a nonlinear optimization search algorithm. The eigenvectors of the original structure are used as repeated basis functions in the analysis of the structural dynamic re-analysis problem. The re-analysis time for acoustic power computations is reduced by calculating and storing modal radiation resistance matrices at discrete frequencies. The matrices are then interpolated within the optimization loop for eigenvalues that fall between stored frequencies. The method is demonstrated by applying multiple-tuned vibration absorbers to an acoustically-excited composite panel. The absorber parameters are optimized with an objective of maximizing the panel's sound power transmission loss. It is shown that in some cases the optimal solution includes vibration absorbers that are tuned very closely in frequency, thus acting effectively as a broadband vibration absorber (BBVA). The numerical model and design optimization method are validated experimentally, and the BBVA is found to be an effective noise abatement tool.

  4. Metamaterial Absorber for Electromagnetic Waves in Periodic Water Droplets

    Yoo, Young Joon; Ju, Sanghyun; Park, Sang Yoon; Ju Kim, Young; Bong, Jihye; Lim, Taekyung; Kim, Ki Won; Rhee, Joo Yull; Lee, YoungPak


    Perfect metamaterial absorber (PMA) can intercept electromagnetic wave harmful for body in Wi-Fi, cell phones and home appliances that we are daily using and provide stealth function that military fighter, tank and warship can avoid radar detection. We reported new concept of water droplet-based PMA absorbing perfectly electromagnetic wave with water, an eco-friendly material which is very plentiful on the earth. If arranging water droplets with particular height and diameter on material surface through the wettability of material surface, meta-properties absorbing electromagnetic wave perfectly in GHz wide-band were shown. It was possible to control absorption ratio and absorption wavelength band of electromagnetic wave according to the shape of water droplet–height and diameter– and apply to various flexible and/or transparent substrates such as plastic, glass and paper. In addition, this research examined how electromagnetic wave can be well absorbed in water droplets with low electrical conductivity unlike metal-based metamaterials inquiring highly electrical conductivity. Those results are judged to lead broad applications to variously civilian and military products in the future by providing perfect absorber of broadband in all products including transparent and bendable materials. PMID:26354891

  5. Study on `Tannix` an absorbent for heavy metals including uranium

    Nakamura, Yasuo [Mitsubishi Nuclear Fuel Co. Ltd., Tokyo (Japan)


    To treat radioactive wastes including uranium and transuranic elements such as plutonium, americium etc., development of an absorbent which can be used to absorb and isolate these elements without producing secondary wastes after treatment was attempted. And an absorbent has been successfully developed by polymerizing tannin, a natural product. It is known that tannin binds heavy metals including uranium resulting to produce their precipitates. There are some reports suggesting its absorption ability for uranium. However, tannin has not been used to isolate a heavy metal from a solution because it is soluble in water. Here, insolubilization of tannin was attempted and a manufacturing method for a gelatinized insoluble tannin named as ``Tannix`` was established. Wattle tannin extracted from Mimosa pudica produced in Africa was dissolved in an alkaline solution and gelatinized by heating after the addition of formalin. Thus obtained insoluble tannin was used after crushing and sieving. This product, ``Tannix`` was able to absorb more than 99% of uranium in the waste. And the absorbed Tannin could be degraded by incineration even at a low temperature, leaving only uranium, but not producing any secondary product. (M.N.)

  6. Dermatological testing of an emollient-treated menstrual pad with a novel foam absorbent core.

    Farage, Miranda A; Segarra, Vanessa Silva; Bramante, Mario; Elsner, Peter; Maibach, Howard I


    Dermatological testing was used to assess the skin compatibility of a menstrual pad with an emollient-treated surface layer and a novel, polymeric absorbent foam core. The test program included: 1) skin patch tests to assess cumulative skin irritation, 2) human repeat insult patch tests to assess the potential for contact sensitization, and 3) repeated application to the popliteal fossa ("behind-the-knee" test) to assess combined chemical irritation and frictional effects. Studies showed the new product and its components to be as mild to skin as other commercially available materials with no evidence for the induction of delayed contact hypersensitivity. Pads with an emollient-based topsheet finish were milder to the skin than pads with a conventional topsheet finish. The test program provides reassurance that the skin compatibility of the new menstrual pad is similar to that of conventional marketed pads with a history of safe use and consumer acceptance.

  7. Estimating Solar Irradiation Absorbed by Photovoltaic Panels with Low Concentration Located in Craiova, Romania

    Ionel L. Alboteanu


    Full Text Available Solar irradiation is one of the important parameters that should be taken into consideration for the design and utilization of a photovoltaic system. Usually, the input parameters of a photovoltaic system are solar irradiation, the ambient environment temperature and the wind speed, and as a consequence most photovoltaic systems are equipped with sensors for measuring these parameters. This paper presents several mathematical models for solar irradiation assessment. The starting point is represented by the mathematical model of extraterrestrial irradiation, and resulting finally in the model for solar irradiation, absorbed by a low concentration photovoltaic panel. These estimating models of solar irradiation have been particularized for the Craiova, Romania, and have been verified through numerical simulation. Regarding terrestrial solar irradiation, four mathematical models have been adopted, namely Adnot, Haurwitz, Kasten and Empirical (EIM. Of these, the most appropriate for the Craiova location were the models Adnot and Empirical. Consequently, for the calculation of the solar irradiation absorbed by the photovoltaic (PV panels with low concentration, these models have been taken into consideration. In this study, a comparative analysis was also carried out with respect to the solar irradiation absorbed by the PV panels without concentration and those with collectedness of the solar radiation. This analysis was based on the results of numerical simulation and experimental tests.

  8. When things go crunch: Gap length effects on a magnetorheological tunable vibration absorber

    Albanese, Anne-Marie; Cunefare, Kenneth


    A tunable vibration absorber (TVA), where the tunable element is a magneto-rheological (MR) elastomer spring, has demonstrated up to a 460% change on tuning frequency. A frequency increase is associated with a significant decrease in the springs static equilibrium length, referred hereto as a crunch. The crunch is caused by magnetic attractive forces across the spring. The spring, an iron-doped silicone gel, is placed between two halves of a low-carbon steel loop. One loop half behaves as an absorber mass, and has approximately 200 turns of magnet wire around it. Driving current through this wire generates a magnetic flux around the steel path and through the MR spring. Beyond a threshold, the magnetic field induces a large frequency shift in the absorber, with a crunch observed across the elastomer. The crunch can occur when the static equilibrium length is unconstrained by geometry, thus a magnetic attractive force shortens the spring length. The relationship between the magnitude of the crunch and the frequency shift will be presented. Additionally, the impact of different initial MR spring lengths on the frequency behavior will be considered. Finally, the frequency variability achievable by MR-spring-based TVAs with and without the crunch will be assessed.

  9. Treatment of displaced radial head fractures by internal fixation with absorbable pins

    HOU Zhen-hai; ZHOU Ji-hong; SHI Jian-guo; SHI Yi-bin; XIA Jun-jie; YAO Jun


    Objective: To study the effect of internal fixation with absorbable pins on treatment of displaced radial head fractures.Methods: From May 1999 to May 2004, 16 patients with displaced radial head fractures (Mason types Ⅱ and Ⅲ) were treated with internal fixation by absorbable pins.The duration of follow-up averaged 22.6 months (12-58 months). The outcome was assessed on the basis of elbow motion, radiographic findings and the functional rating score delineated by Broberg and Morrey.Results: All fractures healed within 10 months without avascular necrosis of radial head. The mean elbow flexion loss was 15°(0°-35°), and pronation and supination decreased by 10° (0°-30°) on average compared with those of the contralateral elbow. Five patients had an excellent result, 6 a good result, and 3 a fair result according to the criteria of Borberg and Morrey.Conclusions: Internal fixation with absorbable pins is an effective method in treating displaced radial head fractures. It can maintain the biomechanical stability of forearm, improve the elbow function and avoid second operation.

  10. An antibacterial and absorbable silk-based fixation material with impressive mechanical properties and biocompatibility

    Shi, Chenglong; Pu, Xiaobing; Zheng, Guan; Feng, Xinglong; Yang, Xuan; Zhang, Baoliang; Zhang, Yu; Yin, Qingshui; Xia, Hong


    Implant-associated infections and non-absorbing materials are two important reasons for a second surgical procedure to remove internal fixation devices after an orthopedic internal fixation surgery. The objective of this study was to produce an antibacterial and absorbable fixation screw by adding gentamicin to silk-based materials. The antibacterial activity was assessed against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) in vitro by plate cultivation and scanning electron microscopy (SEM). We also investigated the properties, such as the mechanical features, swelling properties, biocompatibility and degradation, of gentamicin-loaded silk-based screws (GSS) in vitro. The GSS showed significant bactericidal effects against S. aureus and E. coli. The antibacterial activity remained high even after 4 weeks of immersion in protease solution. In addition, the GSS maintained the remarkable mechanical properties and excellent biocompatibility of pure silk-based screws (PSS). Interestingly, after gentamicin incorporation, the degradation rate and water-absorbing capacity increased and decreased, respectively. These GSS provide both impressive material properties and antibacterial activity and have great potential for use in orthopedic implants to reduce the incidence of second surgeries.

  11. Numerical simulation of the effects of hanging sound absorbers on TABS cooling performance

    Rage, Nils; Kazanci, Ongun Berk; Olesen, Bjarne W.


    to a degradation of the room acoustic comfort. Therefore, challenges arise when this system has to be combined with acoustic requirements. Soffit-hanging sound absorbers embody a promising solution. This study focuses on quantifying their impact on the cooling performance of TABS, assessed by means of the cooling...... capacity coefficient of the ceiling deck. The influence of different ceiling coverage ratios (0-30-45-60 and 80%) as well as the influence of the distance at which the absorbers are placed is studied by numerical simulations using a new, specially-developed TRNSYS Type. Tests were performed in a test room...... simulating a two-person office of 20 m2, with a typical cooling load of 42 W/m2. The results show that covering 60% of the ceiling surface with sound absorbers hanging at 300 mm from the ceiling active deck is expected to reduce the cooling capacity coefficient of TABS by 15.8%. This drops to 25...

  12. Constraining MHD Disk-Winds with X-ray Absorbers

    Fukumura, Keigo; Tombesi, F.; Shrader, C. R.; Kazanas, D.; Contopoulos, J.; Behar, E.


    From the state-of-the-art spectroscopic observations of active galactic nuclei (AGNs) the robust features of absorption lines (e.g. most notably by H/He-like ions), called warm absorbers (WAs), have been often detected in soft X-rays (UFOs) whose physical condition is much more extreme compared with the WAs. Motivated by these recent X-ray data we show that the magnetically- driven accretion-disk wind model is a plausible scenario to explain the characteristic property of these X-ray absorbers. As a preliminary case study we demonstrate that the wind model parameters (e.g. viewing angle and wind density) can be constrained by data from PG 1211+143 at a statistically significant level with chi-squared spectral analysis. Our wind models can thus be implemented into the standard analysis package, XSPEC, as a table spectrum model for general analysis of X-ray absorbers.

  13. Enhancement of acoustical performance of hollow tube sound absorber

    Putra, Azma; Khair, Fazlin Abd; Nor, Mohd Jailani Mohd


    This paper presents acoustical performance of hollow structures utilizing the recycled lollipop sticks as acoustic absorbers. The hollow cross section of the structures is arranged facing the sound incidence. The effects of different length of the sticks and air gap on the acoustical performance are studied. The absorption coefficient was measured using impedance tube method. Here it is found that improvement on the sound absorption performance is achieved by introducing natural kapok fiber inserted into the void between the hollow structures. Results reveal that by inserting the kapok fibers, both the absorption bandwidth and the absorption coefficient increase. For test sample backed by a rigid surface, best performance of sound absorption is obtained for fibers inserted at the front and back sides of the absorber. And for the case of test sample with air gap, this is achieved for fibers introduced only at the back side of the absorber.

  14. On the undamped vibration absorber with cubic stiffness characteristics

    Gatti, G.


    In order to improve the performance of a vibration absorber, a nonlinear spring can be used on purpose. This paper presents an analytical insight on the characteristics of an undamped nonlinear vibration absorber when it is attached to a linear spring-mass-damper oscillator. In particular, the nonlinear attachment is modelled as a Duffing's oscillator with a spring characteristics having a linear positive stiffness term plus a cubic stiffness term. The effects of the nonlinearity, mass ratio and frequency ratio are investigated based on an approximate analytical formulation of the amplitude-frequency equation. Comparisons to the linear case are shown in terms of the frequency response curves. The nonlinear absorber seems to show an improved robustness to mistuning respect to the corresponding linear device. However, such a better robustness may be limited by some instability of the expected harmonic response.

  15. Broadband terahertz metamaterial absorber based on sectional asymmetric structures

    Gong, Cheng; Zhan, Mingzhou; Yang, Jing; Wang, Zhigang; Liu, Haitao; Zhao, Yuejin; Liu, Weiwei


    We suggest and demonstrate the concept and design of sectional asymmetric structures which can manipulate the metamaterial absorber’s working bandwidth with maintaining the other inherent advantages. As an example, a broadband terahertz perfect absorber is designed to confirm its effectiveness. The absorber’s each cell integrates four sectional asymmetric rings, and the entire structure composed of Au and Si3N4 is only 1.9 μm thick. The simulation results show the bandwidth with absorptivity being larger than 90% is extended by about 2.8 times comparing with the conventional square ring absorber. The composable small cell, ultra-thin, and broadband absorption with polarization and incident angle insensitivity will make the absorber suitable for the applications of focal plane array terahertz imaging. PMID:27571941

  16. A simple model for the design of vertical tube absorbers

    Patnaik, V.; Perez-Blanco, H. [Pennsylvania State Univ., University Park, PA (United States); Ryan, W.A. [Gas Research Inst., Chicago, IL (United States)


    The absorption of water vapor in aqueous solutions of lithium bromide is modelled for a falling-film, vertical-tube absorber. The model is based on the solution of three ordinary differential equations to calculate solution bulk and interface concentration and temperature distributions and the coolant temperature distribution. The heat and mass transfer coefficients employed in the equations are extracted from the literature. In this way, the model incorporates recent information on wavy-laminar flows. Under certain conditions, the solution exhibits instabilities in the entrance region of the absorber tube, which are corrected by the introduction of a dampening factor incorporating relevant thermophysical properties. The usefulness of the model for generating absorber performance charts is demonstrated.

  17. MAGIICAT I. The MgII Absorber-Galaxy Catalog

    Nielsen, Nikole M; Kacprzak, Glenn G; Murphy, Michael T


    We describe the MgII Absorber-Galaxy Catalog, MAGIICAT, a compilation of 182 spectroscopically identified intermediate redshift (0.07 0.3 Angstroms], low redshift (z zmed), where zmed = 0.359 is the median galaxy redshift. We find no differences between the luminosity function subsamples, except for a ~0.5 magnitude dimming with decreasing redshift in the B-band for weak absorbing M_B < -18 galaxies. Rest-frame color B-K correlates with M_K at the 8 sigma level for the whole sample but is driven by the strong absorbing, high redshift subsample (6 sigma). We find possible faint-end "roll offs" in both the B- and K-band luminosity functions. Using M_K as a proxy for stellar mass, we infer that in low stellar mass galaxies, MgII absorption is preferentially detected in blue galaxies and the absorption is more likely to be weak.

  18. An Elastic Absorber Theory for a Thin Fabric Sheet

    ZHANG Xi-nan


    The current sound absorption theory which is based on Rayleigh model believes that fibrous material absorb sound by the fluid frictional energy dissipation between the air and the solid fibers. However, Rayleigh model is only useful for a quanlitative understanding of effects in a porous material but not for calculation of the acoustical properties of real absorbent. In this paper, a new vibration sound absorption theory which is totally different from classical theory was put forward. The specific acoustic impedance of fiber layers have been derived from the membrane vibration equation and the sound absorption coefficient calculated agree with test results. The new theory can explain the phenomenon that thin fiber layers exhibit less sound absorption coefficient when it was as the cover fabric of sound absorber, but it is mare efficient to sound absorption when it was hang as the curtains or have back cavity behind it.

  19. Enhancement of acoustical performance of hollow tube sound absorber

    Putra, Azma, E-mail:; Khair, Fazlin Abd, E-mail:; Nor, Mohd Jailani Mohd, E-mail: [Centre for Advanced Research on Energy, Universiti Teknikal Malaysia Melaka, Hang Tuah Jaya, Durian Tunggal Melaka 76100 Malaysia (Malaysia)


    This paper presents acoustical performance of hollow structures utilizing the recycled lollipop sticks as acoustic absorbers. The hollow cross section of the structures is arranged facing the sound incidence. The effects of different length of the sticks and air gap on the acoustical performance are studied. The absorption coefficient was measured using impedance tube method. Here it is found that improvement on the sound absorption performance is achieved by introducing natural kapok fiber inserted into the void between the hollow structures. Results reveal that by inserting the kapok fibers, both the absorption bandwidth and the absorption coefficient increase. For test sample backed by a rigid surface, best performance of sound absorption is obtained for fibers inserted at the front and back sides of the absorber. And for the case of test sample with air gap, this is achieved for fibers introduced only at the back side of the absorber.

  20. A recyclable and regenerable magnetic chitosan absorbent for dye uptake.

    Zhao, Weifeng; Huang, Xuelian; Wang, Yilin; Sun, Shudong; Zhao, Changsheng


    A recyclable and regenerable magnetic polysaccharide absorbent for methylene blue (MB) removal was prepared by coating magnetic polyethyleneimine nanoparticles (PEI@MNPs) with sulfonated chitosan (SCS) and further cross-linked with glutaraldehyde. The driving force for coating is the electrostactic interaction between positively charged PEI and negatively charged SCS. Infrared spectra, zeta potential, thermal gravimetric analysis and X-ray diffraction demonstrated the successful synthesis of magnetic polysaccharide absorbent. The self-assembly of polysaccharide with magnetic nanopartices did not alter the saturation magnetization value of the absorbent confirmed by vibrating sample magnetometer. The nanoparticles showed fast removal (about 30min reached equilibrium) of MB. In particular, the removal ability of MB after desorption did not reduce, demonstrating an excellent regeneration ability. Our study provides new insights into utilizing polysaccharides for environmental remediation and creating advanced magnetic materials for various promising applications.

  1. Absorber Model for CO2 Capture by Monoethanolamine

    Faramarzi, Leila; Kontogeorgis, Georgios; Michelsen, Michael Locht


    The rate-based steady-state model proposed by Gabrielsen et al. (Gabrielsen, J.; Michelsen, M. L.; Kontogeorgis, G. M.; Stenby, E. H. AIChE J. 2006, 52, 10, 3443-3451) for the design of the CO2-2-amino-2-methylpropanol absorbers is adopted and improved for the design of the CO2-monoethanolamine...... absorber. The influence of the application of different mass transfer correlations on the model's performance is investigated. Analytical expressions for the calculation of the enhancement factor for the second order as well as the pseudo-first-order reaction regime are integrated in the model......, and their impact on the model's prediction is compared. The model has been successfully applied to CO2 absorber packed columns and validated against pilot plant data with good agreement....

  2. Preparation and Characterization of Super Absorbent Resin from Natural Cellulose

    李杰; 马凤国; 谭惠民


    The grafting polyacrylamide onto wood pulp cellulose (cell-g-PAM) was performed with cerous ammonium nitrate as the initiator and hydrolyzed to produce the super absorbent resin. The FTIR shows that the polyacrylamide is grafted on the cellulose. After hydrolyzation, part of acrylamino groups are transformed into carboxyl groups. The XRD analysis shows that the graft polymerization occurred at the amorphous section and the surface of the crystal section of cellulose. The SEM graph reveals that there is a layer of polymer on the surface of cellulose fiber and the fibril structure of the cellulose surface is covered. After hydrolyzation, the surface of the product is different from that of cell-g-PAM's and the surface is scraggy. The technical conditions to prepare high water absorbent resin were confirmed. Through the radical graft copolymerization, the high water absorbent resin can be produced from wood pulp cellulose.

  3. Numerical modeling of incline plate LiBr absorber

    Karami, Shahram; Farhanieh, Bijan


    Among major components of LiBr-H2O absorption chillers is the absorber, which has a direct effect on the chillier size and whose characteristics have significant effects on the overall efficiency of absorption machines. In this article, heat and mass transfer process in absorption of refrigerant vapor into a lithium bromide solution of water-cooled incline plate absorber in the Reynolds number range of 5 absorption. An analysis for linear distribution of wall temperature condition carries out to investigate the reliability of the present numerical method through comparing with previous investigation. The effect of plate angle on heat and mass transfer parameters is investigated and the results show that absorption mass flux and heat and mass transfer coefficient increase as the angle of the plate increase. The main parameters of absorber design, namely Nusselt and Sherwood numbers, are correlated as a function of Reynolds Number and the plate angle.

  4. Characteristics of New-type Energy Absorber for Vehicle Collision

    XU Qing-xin; SHEN Rong-ying; ZHOU Hai-ting


    A new type energy absorber was introduced, which is composed of thousands of thin ring plates with different diameters. Because it can switch the impact to thousands of shearing actions among thin ring plates inside the absorber, the impact energy is decentralized and dissipated gradually, the impact acting time is extended and the peak of acceleration is reduced obviously. Numerical simulations by finite element method (FEM) coupled with smoothed particle hydrodynamics (SPH) method were preformed to predict the energy absorption characteristics. Energy absorption ability with different impact velocities was studied and the effects of thickness and material of ring plates were discussed. The sled crash test was carried out to validate the result of simulations. The new type absorber is effective for collision that impact velocity is lower than 40 km/h.

  5. A principle of similarity for nonlinear vibration absorbers

    Habib, G.; Kerschen, G.


    This paper develops a principle of similarity for the design of a nonlinear absorber, the nonlinear tuned vibration absorber (NLTVA), attached to a nonlinear primary system. Specifically, for effective vibration mitigation, we show that the NLTVA should feature a nonlinearity possessing the same mathematical form as that of the primary system. A compact analytical formula for the nonlinear coefficient of the absorber is then derived. The formula, valid for any polynomial nonlinearity in the primary system, is found to depend only on the mass ratio and on the nonlinear coefficient of the primary system. When the primary system comprises several polynomial nonlinearities, we demonstrate that the NLTVA obeys a principle of additivity, i.e., each nonlinear coefficient can be calculated independently of the other nonlinear coefficients using the proposed formula.

  6. Preview control of vehicle suspension system featuring MR shock absorber

    Seong, M. S.; Choi, S. B.; Cho, M. W.; Lee, H. G.


    This paper presents control performance evaluation of optimal preview control algorithm for vehicle suspension featuring MR shock absorber. The optimal preview control algorithm has several advantages such as high control performance over that which is best for a non-preview system. In order to achieve this goal, a commercial MR shock absorber, Delphi MganerideTM, which is applicable to high class passenger vehicle, is adopted and its field-dependent damping force and dynamic responses are experimentally evaluated. Then the governing equation of motion for the full-vehicle model is established and integrated with the MR shock absorber. Subsequently, optimal controller with preview control algorithm is formulated and implemented for vibration suppression of the car body. Control performance of the preview controller is evaluated for the full-vehicle model under random road condition. In addition, the control performances depending on preview distances are evaluated.

  7. Characterization of Absorbent Flow Rate in Towel and Tissue

    Paul D. Beuther


    Full Text Available The quality of a paper towel is often judged based on how quickly it can wipe up a spill. However, the test methods currently available cannot repeatably measure significant differences in absorbent rate between samples. Recent round-robin testing evaluations by TAPPI and CEN organizations have shown that past methods, such as ASTM D5802-95 and TAPPI T561-pm [1], are unreliable due to high variability. The reasons for the lack of repeatability are unclear. The relation between the wicking mechanism and the fundamental absorbent properties needs to be better understood. This paper uses x-ray imaging to show the overall flow characteristics of fluid absorption within a towel, and compares the results to model predictions to show which parameters are important to the process. From this understanding, a revised test method is proposed that provides adequate statistical discernment of absorbent rate properties of tissue on a simple lab-bench scale device.

  8. Graphene induced tunable and polarization-insensitive broadband metamaterial absorber

    Zhang, Yuping; Li, Yue; Cao, Yanyan; Liu, Yuanzhong; Zhang, Huiyun


    We design a tunable and broadband metamaterial absorber in the mid-infrared region based on graphene. The unit cell of the proposed metamaterial absorber consists of circular gold patches, which coupled with a graphene layer, and are separated by a dielectric spacer from the gold film on the bottom. The absorption bandwidth is effectively extended by patterning multi-circular gold patches of different dimension elements with appropriate geometrical parameters in a co-plane. The metamaterial absorber achieves its frequency tunable characteristics via changing the applied voltage or chemical doping to manipulate graphene's Fermi energy. We analyzed the surface current distributions and the distributions of the z-component electric field for understanding the absorption mechanism. Moreover, the design principle here could be regarded as a template to extend bandwidth by introducing more circular patches into each unit cell. Our design has potential applications in various fields of stealth technology, photovoltaic devices, sensors, and broadband communication.

  9. Tunable multichannel absorber composed of graphene and doped periodic structures

    Kong, Xiang-kun; Shi, Xiang-zhu; Mo, Jin-jun; Fang, Yun-tuan; Chen, Xin-lei; Liu, Shao-bin


    A new design for a tunable multichannel compact absorber, which is achieved by using an asymmetric photonic crystal with graphene monolayers, is theoretically proposed. The graphene monolayers are periodically embedded into the first and last dielectric layers. The absorption, reflection, and transmission spectra of the absorber are studied numerically. A perfect absorption channel is achieved because of impedance matching, and channel number can be modulated by changing periodic number. The characteristic properties of the absorption channel depend on graphene conductivity, which can be controlled via the gate voltage. The proposed structure works as a perfect absorber that is independent from polarization. It has potential applications in the design of multichannel filters, thermal detectors, and electromagnetic wave energy collectors.

  10. Hafnium as a neutron absorber in research reactors

    Jatuff, F.E.; Villarino, E.A. [INVAP S.E., S.C. de Bariloche (Argentina)


    Research reactors usually require the periodic replacement of control rods because of the burnup of the neutron absorber material, even if devices have been mainly withdrawn. The purpose of this paper is the study of the reactivity worth of hafnium as a neutron absorber in the multi-purpose-type research reactor (MPTRR). The MPTRR design develops 20 MW, and it is configured by five rows of six low-enriched uranium (200% enrichment) materials test reactor fuels inside a Zircaloy chimney. The standard control plates are given by two rows of three plates of silver-indium-cadmium alloy (85% silver, 10% indium, and 5% cadmium, in weight percents; 0.26 cm of maximum absorber width), separating the central three rows of fuel elements from the peripheral first and fifth rows. The burnup of control plates decreases the reactivity worth below the licensing criteria in {approximately}6 months.

  11. An effective absorbing boundary algorithm for acoustical wave propagator


    In this paper, Berenger's perfectly matched layer (PML) absorbing boundary condition for electromagnetic waves is introduced as the truncation area of the computational domain to absorb one-dimensional acoustic wave for the scheme of acoustical wave propagator (AWP). To guarantee the efficiency of the AWP algorithm, a regulated propagator matrix is derived in the PML medium.Numerical simulations of a Gaussian wave packet propagating in one-dimensional duct are carried out to illustraze the efficiency of the combination of PML and AWP. Compared with the traditional smoothing truncation windows technique of AWP, this scheme shows high computational accuracy in absorbing acoustic wave when the acoustical wave arrives at the computational edges. Optimal coefficients of the PML configurations are also discussed.

  12. Design of electromagnetic shock absorbers for automotive suspensions

    Amati, Nicola; Festini, Andrea; Tonoli, Andrea


    Electromechanical dampers seem to be a valid alternative to conventional shock absorbers for automotive suspensions. They are based on linear or rotative electric motors. If they are of the DC-brushless type, the shock absorber can be devised by shunting its electric terminals with a resistive load. The damping force can be modified by acting on the added resistance. To supply the required damping force without exceeding in size and weight, a mechanical or hydraulic system that amplifies the speed is required. This paper illustrates the modelling and design of such electromechanical shock absorbers. This paper is devoted to describe an integrated design procedure of the electrical and mechanical parameters with the objective of optimising the device performance. The application to a C class front suspension car has shown promising results in terms of size, weight and performance.

  13. Infrared Perfect Ultra-narrow Band Absorber as Plasmonic Sensor

    Wu, Dong; Liu, Yumin; Li, Ruifang; Chen, Lei; Ma, Rui; Liu, Chang; Ye, Han


    We propose and numerically investigate a novel perfect ultra-narrow band absorber based on a metal-dielectric-metal-dielectric-metal periodic structure working at near-infrared region, which consists of a dielectric layer sandwiched by a metallic nanobar array and a thin gold film over a dielectric layer supported by a metallic film. The absorption efficiency and ultra-narrow band of the absorber are about 98 % and 0.5 nm, respectively. The high absorption is contributed to localized surface ...

  14. Energy deposition and radiological studies for the LBNF Hadron Absorber

    Rakhno, I L; Tropin, I S; Eidelman, Y I


    Results of detailed Monte Carlo energy deposition and radiological studies performed for the LBNF hadron absorber with the MARS15 code are described. The model of the entire facility, that includes a pion-production target, focusing horns, target chase, decay channel, hadron absorber system - all with corresponding radiation shielding - was developed using the recently implemented ROOT-based geometry option in the MARS15 code. Both normal operation and accidental conditions were studied. Results of detailed thermal calculations with the ANSYS code helped to select the most viable design options.

  15. Application of Intrared Absorbers to Nylon 6,6


    The dyeing procedures, Appendix III, all utilized 40:1 liquor -cloth ratios at boiling temperatures. The in- frared absorbers were applied at 0.2...s were adjusted by acetic acid or ammonia . - -■■-■ ■ - - - — ...—n . <<af-’"’"" >-T—■"— »inmmn Table I Reflectance of Cyasorb IR 99 Absorbers...a formulation of dyes that approach the ideal camouflage curve is to search for acid dyes with strong infrared absorption bands. The spectra of

  16. Dual band metamaterial perfect absorber based on Mie resonances

    Liu, Xiaoming; Lan, Chuwen; Li, Bo; Zhou, Ji, E-mail: [State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Bi, Ke [School of Science, Beijing University of Posts and Telecommunications, Beijing 100876 (China); Zhao, Qian [State Key Lab of Tribology, Department of Precision Instruments and Mechanology, Tsinghua University, Beijing 100084 (China)


    We numerically and experimentally demonstrated a polarization insensitive dual-band metamaterial perfect absorber working in wide incident angles based on the two magnetic Mie resonances of a single dielectric “atom” with simple structure. Two absorption bands with simulated absorptivity of 99% and 96%, experimental absorptivity of 97% and 94% at 8.45 and 11.97 GHz were achieved due to the simultaneous magnetic and electric resonances in dielectric “atom” and copper plate. Mie resonances of dielectric “atom” provide a simple way to design metamaterial perfect absorbers with high symmetry.

  17. Preparation of A New Type of Stress-absorbed Material

    WU Shao-peng; YANG Tao; YUAN Hai-qing


    Neoprene latex modified emulsified bitumen and fine aggregate are used to prepare a new type of stress-absorbed material, which has strong ability of anti-reflective cracking on asphalt concrete over layer-constructed upon a semi-rigid type base course or cement concrete pavement block. Experimental results demonstrate the stress-absorbed material have excellent mechanical properties including a low modulus of elasticity, high ultimate tensile stress and strain, and a strong distortion ability. Stress concentration in asphalt over layer originated by temperature changes and traffic loads can be alleviated.

  18. Integrated polymer waveguides for absorbance detection in chemical analysis systems

    Mogensen, Klaus Bo; El-Ali, Jamil; Wolff, Anders


    . The emphasis of this paper is on the signal-to-noise ratio of the detection and its relation to the sensitivity. Two absorbance cells with an optical path length of 100 μm and 1000 μm were characterized and compared in terms of sensitivity, limit of detection and effective path length for measurements......A chemical analysis system for absorbance detection with integrated polymer waveguides is reported for the first time. The fabrication procedure relies on structuring of a single layer of the photoresist SU-8, so both the microfluidic channel network and the optical components, which include planar...

  19. Resonant Inerter Based Absorbers for a Selected Global Mode

    Krenk, Steen


    The paper presents calibration and efficiency analyses for two different configurations of a resonant vibration absorber consisting of a spring, a damper and an inerter element. In the two configurations the damper is either in parallel with the spring or with the inerter element. A calibration......-resonant modes. The calibration procedure is given a unified format for the two absorber types, and the high efficiency – evaluated as the ability to reproduce the selected dynamic amplification level of the resonant mode – is demonstrated....

  20. Photophoretic trampoline - Interaction of single airborne absorbing droplets with light

    Esseling, Michael; Alpmann, Christina; Denz, Cornelia


    We present the light-induced manipulation of absorbing liquid droplets in air. Ink droplets from a printer cartridge are used to demonstrate that absorbing liquids - just like their solid counterparts - can interact with regions of high light intensity due to the photophoretic force. It is shown that droplets follow a quasi-ballistic trajectory after bouncing off a high intensity light sheet. We estimate the intensities necessary for this rebound of airborne droplets and change the droplet trajectories through a variation of the manipulating light field.

  1. Formulation and justification of the Wheeler-Feynman absorber theory

    Schulman, L. S.


    The “absorber theory” of Wheeler and Feynman is supposed to justify the use of retarded potentials in ordinary electromagnetic calculations despite a fundamentally time symmetric interaction. We restate the thesis of absorber theory as follows: here exist causal solutions of time symmetric electrodynamics. In our formulation, absorption need only take place in one direction of time (the future) rather than both, as seems to be required by Wheeler and Feynman. Even with complete absorption, however, the effects of advanced interactions are not entirely eliminated and a residual field may introduce a degree of indeterminacy into particle trajectories obtained using retarded potentials alone.

  2. The arrow of electromagnetic time and the generalized absorber theory

    Cramer, John G.


    The problem of the direction of electromagnetic time, i.e., the complete dominance of retarded electromagnetic radiation over advanced radiation in the universe, is considered in the context of a generalized form of the Wheeler-Feynman absorber theory in an open expanding universe with a singularity at T=0. It is shown that the application of a four-vector reflection boundary condition at the singularity leads to the observed dominance of retarded radiation; it also clarifies the role of advanced and retarded waves in the emission of very weakly absorbed radiation such as neutrinos.

  3. Arrow of electromagnetic time and the generalized absorber theory

    Cramer, J.G.


    The problem of the direction of electromagnetic time, i.e., the complete dominance of retarded electromagnetic radiation over advanced radiation in the universe, is considered in the context of a generalized form of the Wheeler--Feynman absorber theory in an open expanding universe with a singularity at T = 0. It is shown that the application of a four-vector reflection boundary condition at the singularity leads to the observed dominance of retarded radiation; it also clarifies the role of advanced and retarded waves in the emission of very weakly absorbed radiation such as neutrinos.

  4. The Wheeler-Feynman absorber theory: A reinterpretation?

    Ridderbos, T. M.


    The “reinterpretation” of the Wheeler-Feynman absorber theory of radiation, as presented by H. Price in Refs. 1 and 2, is shown not to be a reinterpretation of the mathematical framework of the theory, but an alteration of the theory, which renders it asymmetric. It is shown that Price is mistaken in accusing Wheeler and Feynman of presenting flawed arguments as to whether the advanced and retarded components are distinct; and about the reasons for excluding the time-reversed version of the absorber theory.

  5. Design of Absorbing Wave Maker based on Digital Filters

    Christensen, Morten; Frigaard, Peter

    An absorbing wave maker operated by means of on-line signals from digital FIR filters is presented. Surface elevations are measured in two positions in front of the wave maker. The reflected wave train is seperated by the sum of the incident and reflected wave trains by means of digital filtering...... and subsequent superposition of the measured surface elevations. The motion of the wave paddle required to absorb reflected waves is determined and added to the original wave paddle control signal. Irregular wave tests involving test structures with different degrees of reflection show that excellent absorption...

  6. Extending the Bandwidth of Electric Ring Resonator Metamaterial Absorber

    LUO Hao; WANG Tao; GONG Rong-Zhou; NIE Yan; WANG Xian


    An efficient method is proposed to extend the bandwidth of a metamaterial absorber with multi-resonance structure. The basic unit cell of a metamaterial absorber consists of the electric ring resonator, dielectric substrate (FR-4)and split-wire. By assembling five sandwiched structures with different geometric dimensions into a unit cell, we obtain the superposition of five different absorption peaks.Finally the bandwidth of metamaterial absorption is extended and the full width at half maximum is up to 1.3 GHz. The simulated and experimental results are consistent.

  7. RF Electromagnetic Field Treatment of Tetragonal Kesterite CZTSSe Light Absorbers

    Semenenko, Mykola O.; Babichuk, Ivan S.; Kyriienko, Oleksandr; Bodnar, Ivan V.; Caballero, Raquel; Leon, Maximo


    In this work, we propose a method to improve electro-optical and structural parameters of light-absorbing kesterite materials. It relies on the application of weak power hydrogen plasma discharges using electromagnetic field of radio frequency range, which improves homogeneity of the samples. The method allows to reduce strain of light absorbers and is suitable for designing solar cells based on multilayered thin film structures. Structural characteristics of tetragonal kesterite Cu2ZnSn(S, Se)4 structures and their optical properties were studied by Raman, infrared, and reflectance spectroscopies. They revealed a reduction of the sample reflectivity after RF treatment and a modification of the energy band structure.

  8. Absorbed Power Minimization in Cellular Users with Circular Antenna Arrays

    Christofilakis, Vasilis; Votis, Constantinos; Tatsis, Giorgos; Raptis, Vasilis; Kostarakis, Panos


    Nowadays electromagnetic pollution of non ionizing radiation generated by cellular phones concerns millions of people. In this paper the use of circular antenna array as a means of minimizing the absorbed power by cellular phone users is introduced. In particular, the different characteristics of radiation patterns produced by a helical conventional antenna used in mobile phones operating at 900 MHz and those produced by a circular antenna array, hypothetically used in the same mobile phones, are in detail examined. Furthermore, the percentage of decrement of the power absorbed in the head as a function of direction of arrival is estimated for the circular antenna array.

  9. Brown carbon: a significant atmospheric absorber of solar radiation?

    Y. Feng


    Full Text Available Several recent observational studies have shown organic carbon aerosols to be a significant source of absorption of solar radiation. The absorbing part of organic aerosols is referred to as "brown" carbon (BrC. Using a global chemical transport model and a radiative transfer model, we estimate for the first time the enhanced absorption of solar radiation due to BrC in a global model. The simulated wavelength dependence of aerosol absorption, as measured by the absorption Ångström exponent (AAE, increases from 0.9 for non-absorbing organic carbon to 1.2 (1.0 for strongly (moderately absorbing BrC. The calculated AAE for the strongly absorbing BrC agrees with AERONET spectral observations at 440–870 nm over most regions but overpredicts for the biomass burning-dominated South America and southern Africa, in which the inclusion of moderately absorbing BrC has better agreement. The resulting aerosol absorption optical depth increases by 18% (3% at 550 nm and 56% (38% at 380 nm for strongly (moderately absorbing BrC. The global simulations suggest that the strongly absorbing BrC contributes up to +0.25 W m−2 or 19% of the absorption by anthropogenic aerosols, while 72% is attributed to black carbon, and 9% is due to sulfate and non-absorbing organic aerosols coated on black carbon. Like black carbon, the absorption of BrC (moderately to strongly inserts a warming effect at the top of the atmosphere (TOA (0.04 to 0.11 W m−2, while the effect at the surface is a reduction (−0.06 to −0.14 W m−2. Inclusion of the strongly absorption of BrC in our model causes the direct radiative forcing (global mean of organic carbon aerosols at the TOA to change from cooling (−0.08 W m−2 to warming (+0.025 W m−2. Over source regions and above clouds, the absorption of BrC is higher and thus can play an important role in photochemistry and the hydrologic cycle.

  10. Wild bees preferentially visit Rudbeckia flower heads with exaggerated ultraviolet absorbing floral guides

    Lisa Horth


    Full Text Available Here, we report on the results of an experimental study that assessed the visitation frequency of wild bees to conspecific flowers with different sized floral guides. UV absorbent floral guides are ubiquitous in Angiosperms, yet surprisingly little is known about conspecific variation in these guides and very few studies have evaluated pollinator response to UV guide manipulation. This is true despite our rich understanding about learning and color preferences in bees. Historical dogma indicates that flower color serves as an important long-range visual signal allowing pollinators to detect the flowers, while floral guides function as close-range signals that direct pollinators to a reward. We initiated the work presented here by first assessing the population level variation in UV absorbent floral guides for conspecific flowers. We assessed two species, Rudbeckia hirta and R. fulgida. We then used several petal cut-and-paste experiments to test whether UV floral guides can also function to attract visitors. We manipulated floral guide size and evaluated visitation frequency. In all experiments, pollinator visitation rates were clearly associated with floral guide size. Diminished floral guides recruited relatively few insect visitors. Exaggerated floral guides recruited more visitors than smaller or average sized guides. Thus, UV floral guides play an important role in pollinator recruitment and in determining the relative attractiveness of conspecific flower heads. Consideration of floral guides is therefore important when evaluating the overall conspicuousness of flower heads relative to background coloration. This work raises the issue of whether floral guides serve as honest indicators of reward, since guide size varies in nature for conspecific flowers at the same developmental stage and since preferences for larger guides were found. To our knowledge, these are the first cut-and-paste experiments conducted to examine whether UV absorbent

  11. Effect of thermal-treatment sequence on sound absorbing and mechanical properties of porous sound-absorbing/thermal-insulating composites

    Huang Chen-Hung


    Full Text Available Due to recent rapid commercial and industrial development, mechanical equipment is supplemented massively in the factory and thus mechanical operation causes noise which distresses living at home. In livelihood, neighborhood, transportation equipment, jobsite construction noises impact on quality of life not only factory noise. This study aims to preparation technique and property evaluation of porous sound-absorbing/thermal-insulating composites. Hollow three-dimensional crimp PET fibers blended with low-melting PET fibers were fabricated into hollow PET/low-melting PET nonwoven after opening, blending, carding, lapping and needle-bonding process. Then, hollow PET/low-melting PET nonwovens were laminated into sound-absorbing/thermal-insulating composites by changing sequence of needle-bonding and thermal-treatment. The optimal thermal-treated sequence was found by tensile strength, tearing strength, sound-absorbing coefficient and thermal conductivity coefficient tests of porous composites.

  12. Development of the FracTherm absorber - simulations and experiments; Entwicklung des FracTherm-Absorbers - Simulationen und Experimente

    Hermann, M. [Fraunhofer Inst. fuer Solare Energiesysteme, Freiburg (Germany)


    The energy efficiency of a solar absorber is strongly influenced by the flow of the heat transfer fluid. In order to obtain a high thermal efficiency (expressed by a high collector efficiency factor F'), the volume flow distribution should be uniform all over the absorber. Moreover, the pressure drop should be low in order to reduce the primary energy which is needed to drive the pump. Conventional absorber designs often show disadvantages (e.g. high pressure drop for serial connection, non-uniform flow distribution for parallel connection). This paper describes an alternative, ''bionic'' approach with a multiple branched, ''fractal'' channel design for solar absorbers. The aim of a current research work, which is sponsored by the Scholarship Programme of the German Federal Environmental Foundation (DBU), is to compare these structures with conventional ones concerning the pressure drop and the thermal efficiency. In order to achieve a fractal channel design on a given area, an algorithm (patent pending) and a simulation programme called FracTherm were developed. FracTherm allows to calculate the volume flow distribution, the pressure drop as well as the distribution of the collector efficiency factor F' and the fluid temperature. The simulations show that rather high F' values (about 0.97) can be expected (water; about 50 l/(m{sup 2}h)). Flow experiments with ink and thermography with an absorber model also revealed a uniform flow distribution and indicate a high thermal efficiency. Three aluminium test absorbers (590 mm x 1000 mm) were built by the Pechiney Rhenalu Chambery Company using the rollbond process. (orig.)

  13. Assessment of bovine biomaterials containing bone morphogenetic proteins bound to absorbable hydroxyapatite in rabbit segmental bone defects Avaliação de biomateriais bovinos contendo proteínas morfogenéticas ósseas absorvidas a hidroxiapatita em defeitos ósseos segmentares em coelhos

    Evelyn Hasegawa Gonçalves Caporali


    Full Text Available PURPOSE: To evaluate the osteo-regenerative capacity of two proprietary bone grafting materials, using a segmental defect model in both radial diaphyses of rabbits. METHODS: The right defect was filled with pooled bone morphogenetic proteins (pBMPs bound to absorbable ultrathin powdered hydroxyapatite (HA mixed with inorganic and demineralized bone matrix and bone-derived collagen, derived from bovine bone (Group A. The left defect was filled with bovine demineralized bone matrix and pBMPs bound to absorbable ultrathin powdered HA (Group B. In both groups, an absorbable membrane of demineralized bovine cortical was used to retain the biomaterials in the bone defects, and to guide the tissue regeneration. The rabbits were euthanized 30, 90 and 150 days after surgery. Radiographic, tomographic and histologic evaluations were carried out on all specimens. RESULTS: At 30 days, the demineralized cortical bone cover was totally resorbed in both groups. HA was totally resorbed from Group A defects, whereas HA persisted in Group B defects. A prominent foreign body reaction was evident with both products, more pronounced in sections from Group B. At 90 days, the defects in Group B exhibited more new bone than Group A. However, at 150 days after surgery, neither treatment had stimulated complete repair of the defect. CONCLUSION: The partial bone healing of the segmental defect occurred with low or none performance of the biomaterials tested.OBJETIVO: Avaliar a capacidade osteo-regenerativa de dois biomateriais utilizando um modelo de defeito segmentar efetuado nas diáfises do rádio de coelhos. MÉTODOS: O defeito direito foi preenchido com pool de proteínas morfogenéticas ósseas (pBMPs e hidroxiapatita em pó ultrafina absorvível (HA combinada com matriz óssea inorgânica desmineralizada e colágeno, derivados do osso bovino (Grupo A. O defeito esquerdo foi preenchido com matriz óssea desmineralizada bovina com pBMPs e hidroxiapatita em p

  14. Single scattering properties of semi-embedded soot morphologies with intersecting and non-intersecting surfaces of absorbing spheres and non-absorbing host

    Wu, Yu; Cheng, Tianhai; Zheng, Lijuan; Chen, Hao; Xu, Hui


    The optical properties of light absorbing soot aerosols generally change through interactions with weakly absorbing particles, resulting in complex mixing states, and have been highlighted as a major uncertainty in assessing their radiative forcing and climatic impact. The single scattering properties of soot aggregates partially embedded in the host sulfate particle (semi-embedded soot-containing mixtures) are investigated for two kinds of morphologies with intersecting and non-intersecting surfaces. The surfaces cannot be overlapped in the non-intersecting surface morphology, while the intersecting surface morphology is unconstrained. Based on the modified diffusion limited aggregation (DLA) algorithm, the models with non-intersecting surfaces are simulated and applied for the single scattering calculations of semi-embedded soot-containing mixtures using the superposition T-matrix (STM) method. For comparison, the models with intersecting surfaces are simulated with the same morphological parameters, but some soot monomers are intersected by the host sphere. Due to the limitation of current STM method, the optical properties of these models with intersecting surfaces are calculated using the discrete dipole approximation (DDA) method. The soot volume fractions outside sulfate host (Fs,out) are introduced and applied to characterize the mixing states of the soot-containing aerosols. These simulations show that the absorption cross-sections of those internally, deeply, half and slightly embedded mixed soot particles (Fs,out = 0.0, 0.2, 0.5, 0.8) are ~105%, ~65%, ~43% and ~14% larger than the semi-external mixtures (Fs,out = 1.0), respectively. The results also indicate that the differences of extinction cross-sections, single scattering albedo (SSA) and asymmetry parameter (ASY) between simulations with intersecting and non-intersecting surfaces are small (infrared wavelengths, the relative deviations of absorption cross-sections between these different

  15. Exchanging Ohmic Losses in Metamaterial Absorbers with Useful Optical Absorption for Photovoltaics

    Vora, Ankit; Pala, Nezih; Kulkarni, Anand; Pearce, Joshua M; Güney, Durdu Ö


    Using metamaterial absorbers, we have shown that metallic layers in the absorbers do not necessarily constitute undesired resistive heating problem for photovoltaics. Tailoring the geometric skin depth of metals and employing the natural bulk absorbance characteristics of the semiconductors in those absorbers can enable the exchange of undesired resistive losses with the useful optical absorbance in the active semiconductors. Thus, Ohmic loss dominated metamaterial absorbers can be converted into photovoltaic near-perfect absorbers with the advantage of harvesting the full potential of light management offered by the metamaterial absorbers. Based on experimental permittivity data for indium gallium nitride, we have shown that between 75%-95% absorbance can be achieved in the semiconductor layers of the converted metamaterial absorbers. Besides other metamaterial and plasmonic devices, our results may also apply to photodectors and other metal or semiconductor based optical devices where resistive losses and p...

  16. The changes in optical absorbance of ZrO{sub 2} thin film with the rise of the absorbed dose

    Abayli, D., E-mail:; Baydogan, N., E-mail: [Energy Institute, Istanbul Technical University, Ayazaga Campus, 34469, Istanbul (Turkey)


    In this study, zirconium oxide (ZrO{sub 2}) thin film samples prepared by sol–gel method were irradiated using Co-60 radioisotope as gamma source. Then, it was investigated the ionizing effect on optical properties of ZrO{sub 2} thin film samples with the rise of the absorbed dose. The changes in the optical absorbance of ZrO{sub 2} thin films were determined by using optical transmittance and the reflectance measurements in the range between 190 – 1100 nm obtained from PG Instruments T80 UV-Vis spectrophotometer.

  17. Methods for applying microchannels to separate methane using liquid absorbents, especially ionic liquid absorbents from a mixture comprising methane and nitrogen

    Tonkovich, Anna Lee Y.; Litt, Robert D.; Dongming, Qiu; Silva, Laura J.; Lamont, Micheal Jay; Fanelli, Maddalena; Simmons, Wayne W.; Perry, Steven


    Methods of using microchannel separation systems including absorbents to improve thermal efficiency and reduce parasitic power loss. Energy is typically added to desorb methane and then energy or heat is removed to absorb methane using a working solution. The working solution or absorbent may comprise an ionic liquid, or other fluids that demonstrate a difference in affinity between methane and nitrogen in a solution.

  18. Four-year clinical follow-up of the ABSORB everolimus-eluting bioresorbable vascular scaffold in patients with de novo coronary artery disease: The ABSORB trial

    D. Dudek (Dariusz); Y. Onuma (Yoshinobu); J.A. Ormiston (John); L. Thuesen (Leif); K. Miquel-Hébert (Karine); P.W.J.C. Serruys (Patrick)


    textabstractAims: The first-in-man ABSORB Cohort A trial demonstrated the bioresorption of the ABSORB BVS (Abbott Vascular, Santa Clara, CA, USA) at two years. This report describes the 4-year clinical outcomes. Methods and results: The ABSORB Cohort A trial enrolled 30 patients with a single de nov

  19. Recycling of waste tyre rubber into oil absorbent.

    Wu, B; Zhou, M H


    The abundant and indiscriminant disposal of waste tyres has caused both health and environmental problems. In this work, we provide a new way to dispose off waste tyres by reusing the waste tyre rubber (WTR) for oil absorptive material production. To investigate this feasibility, a series of absorbents were prepared by graft copolymerization-blending method, using waste tyre rubber and 4-tert-butylstyrene (tBS) as monomers. Divinylbenzene (DVB) and benzoyl peroxide (BPO) were employed as crosslinker and initiator, respectively. The existence of graft-blends (WTR-g-tBS) was determined by FTIR spectrometry and verified using thin-layer chromatography (TLC). In addition, the thermal properties of WTR-g-tBS were confirmed by a thermogravimetric analyzer (TGA). Oil absorbency of the grafted-blends increased with increases in either feed ratio of WTR to tBS or DVB concentration. This absorbency reached a maximum of 24.0gg(-1) as the feed ratio and DVB concentration were 60/40 and 1wt%, respectively, after which it decreased. At other ratios and concentrations the absorbency decreased. The gel fraction of grafted-blends increased with increasing concentration of DVB. Oil-absorption processes in pure toluene and crude oil diluted with toluene were found to adhere to first-order absorption kinetics. Furthermore, the oil-absorption rate in diluted crude oil was observed to be lower than pure toluene.

  20. Red fluorescent protein with reversibly photoswitchable absorbance for photochromic FRET

    Subach, F.V.; Zhang, L.; Gadella, T.W.J.; Gurskaya, N.G.; Lukyanov, K.A.; Verkhusha, V.V.


    We have developed the first red fluorescent protein, named rsTagRFP, which possesses reversibly photoswitchable absorbance spectra. Illumination with blue and yellow light switches rsTagRFP into a red fluorescent state (ON state) or nonfluorescent state (OFF state), respectively. The ON and OFF stat


    LIAO Changrong; ZHANG Honghui; YU Miao; CHEN Weimin


    The Bingham constitutive model, which is previously used in depiction of magnetorheological (MR) fluids rheological behaviors for design devices, exhibits discontinuous characteristics in representation of pre-yield behaviors and post-yield behaviors. A Biviscous constitutive model is presented to depict rheological behaviors of MR fluids and design automotive shock absorber. Quasi-static flow equations of MR fluids in annular channels are set theoretically up based on Navier-Stokes equations and several rational simplifications are made. And both flow boundary conditions and flow compatibilities conditions are established. Meantime, analytical velocity profiles of MR fluids though annular channels are obtained via solution of the quasi-static flow equations using Biviscous constitutive model. The prediction methodology of damping force offered by MR fluid shock absorber is formulated and damping performances are predicated in order to determine design parameters. MR fluid shock absorber for Mazda 323 car suspension is designed and fabricated in Chongqing University, China. Measurements from sinusoidal displacement cycle by Shanchuan Shock Absorber Ltd. of China North Industry Corporation reveal that the analytical methodology and design theory are reasonable.

  2. On the diversity of O vi absorbers at high redshift

    Draganova, Nadya


    In this thesis, we systematically analyze the properties of intergalactic \\Ovi absorbing gas structures at high redshift using optical spectra with intermediate ($\\sim 6.6$ \\kms FWHM) and high ($\\sim 4.0$ \\kms FWHM) resolution, obtained with UVES/VLT. We complement our analysis with synthetic spectra obtained from extensive cosmological simulations that are part of the OWLS project (Schaye et al. 2010). Our main conclusions are: 1) Both the observations and simulations imply that \\Ovi absorbers at high redshift arise in structures spanning a broad range of scales and different physical conditions. When the \\Ovi components are characterized by small Doppler parameters, the ionizing mechanism is most likely photoionization; otherwise, collisional ionization is the dominant mechanism. 2) The baryon- and metal-content of the \\Ovi absorbers at $z\\approx2$ is less than one per cent of the total mass-density of baryons and metals at that redshift. Therefore, \\Ovi absorbers do not trace the bulk of baryons and metals...

  3. Impact of structural heterogeneity in solar absorber layers (Conference Presentation)

    Toney, Michael


    Impact of structural heterogeneity in solar absorber layers Michael F Toney SLAC National Accelerator Laboratory Structural and morphological heterogeneity is common in thin film and emerging solar cell absorber layers, including organic photovoltaic bulk heterojunctions (OPV BHJs), hybrid organic-inorganic perovskites (HOIP), and Cu2ZnSn(S,Se)4 (CZTSSe), and has a significant impact on the (opto)electronic heterogeneity and hence absorber properties. In this talk I will use X-ray based methods, including scattering and spectroscopies, to characterize and quantify the heterogeneity in OPV BHJs and HOIP absorber layers. The BHJ films are blends of the small molecule X2 and [6,6]-phenyl C71 butyric acid methyl ester (PC71BM) where it has been established that there are three distinct region of the films - pure PC71BM, pure X2 and intimately mixed X2:PC71BM. This talk will show how the absolute concentration of the mixed phase can be used to explain the large PC71BM:X2 composition range where good performance is observed [1]. The talk will also show that spin cast CH3NH3PbI3 films consistent of both crystalline and amorphous regions, which can explain previous heterogeneity in the PL imaging [2]. [1] Huang et al., Adv. Energy Mater. 4, 1301886 (2014). [2] deQuilettes et al., Science 348, 683 (2015).

  4. Fission life-time calculation using a complex absorbing potential

    Scamps, Guillaume


    A comparison between the semi-classical approximation and the full quantum calculation with a complex absorbing potential is made with a model of the fission of 258Fm. The potential barrier is obtained with the constrained Skyrme HF+BCS theory. The life-time obtained by the two calculations agree with each other the difference being only by 25%.

  5. Bottom Slamming on Heaving Point Absorber Wave Energy Devices

    De Backer, Griet; Vantorre, Marc; Frigaard, Peter;


    Oscillating point absorber buoys may rise out of the water and be subjected to bottom slamming upon re-entering the water. Numerical simulations are performed to estimate the power absorption, the impact velocities and the corresponding slamming forces for various slamming constraints. Three buoy...

  6. The Kinematic Evolution of Strong MgII Absorbers

    Mshar, Andrew C; Lynch, Ryan S; Churchill, Chris; Kim, Tae-Sun


    We consider the evolution of strong (W_r(2796) > 0.3A) MgII absorbers, most of which are closely related to luminous galaxies. Using 20 high resolution quasar spectra from the VLT/UVES public archive, we examine 33 strong MgII absorbers in the redshift range 0.3 < z < 2.5. We compare and supplement this sample with 23 strong MgII absorbers at 0.4 < z < 1.4 observed previously with HIRES/Keck. We find that neither equivalent width nor kinematic spread (the optical depth weighted second moment of velocity) of MgII2796 evolve. However, the kinematic spread is sensitive to the highest velocity component, and therefore not as sensitive to additional weak components at intermediate velocities relative to the profile center. The fraction of absorbing pixels within the full velocity range of the system does show a trend of decreasing with decreasing redshift. Most high redshift systems (14/20) exhibit absorption over the entire system velocity range, which differs from the result for low redshift systems ...

  7. A compact analytic solution describing optoacoustic phenomenon in absorbing fluid

    Cundin, Luisiana; Barsalou, Norman; Voss, Shannon


    Derivation of an analytic, closed-form solution for Q-switched laser induced optoacoustic phenomenon in absorbing fluid media is presented. The solution assumes spherical symmetry as well for the forcing function, which represents heat deposition from Q-switched lasers. The Greens solution provided is a suitable kernel to generate more complex solutions arising in optoacoustics, optoacoustic spectroscopy, photoacoustic and photothermal problems.

  8. Experimental dermatoplasty of skin defects with an absorbable bioplastic preparation.

    Bornemisza, G; Ladányi, J; Mikó, I


    Experimental dermatoplasty was performed with fibrin sponge preparation in the rabbit, during the course of which the whole skin thickness was substituted. The fibrin sponge was fixed to the skin-edges with surgical adhesive. The gradually absorbed fibrin was replaced by the migrating epithelium such that epithelization developed gradually. In special cases this method can be recommended for clinical purposes.

  9. Highly Absorbent Antibacterial Hemostatic Dressing for Healing Severe Hemorrhagic Wounds

    Ting-Ting Li


    Full Text Available To accelerate healing of severe hemorrhagic wounds, a novel highly absorbent hemostatic dressing composed of a Tencel®/absorbent-cotton/polylactic acid nonwoven base and chitosan/nanosilver antibacterial agent was fabricated by using a nonwoven processing technique and a freeze-drying technique. This study is the first to investigate the wicking and water-absorbing properties of a nonwoven base by measuring the vertical wicking height and water absorption ratio. Moreover, blood agglutination and hemostatic second tests were conducted to evaluate the hemostatic performance of the resultant wound dressing. The blending ratio of fibers, areal weight, punching density, and fiber orientation, all significantly influenced the vertical moisture wicking property. However, only the first two parameters markedly affected the water absorption ratio. After the nonwoven base absorbed blood, scanning electron microscope (SEM observation showed that erythrocytes were trapped between the fibrin/clot network and nonwoven fibers when coagulation pathways were activated. Prothrombin time (PT and activated partial thromboplastin time (APTT blood agglutination of the resultant dressing decreased to 14.34 and 50.94 s, respectively. In the femoral artery of the rate bleeding model, hemostatic time was saved by 87.2% compared with that of cotton cloth. Therefore, the resultant antibacterial wound dressing demonstrated greater water and blood absorption, as well as hemostatic performance, than the commercially available cotton cloth, especially for healing severe hemorrhagic wounds.

  10. Practical design of a nonlinear tuned vibration absorber

    Grappasonni, C.; Habib, G.; Detroux, T.


    The aim of the paper is to develop a new nonlinear tuned vibration absorber (NLTVA) capable of mitigating the vibrations of nonlinear systems which are known to exhibit frequency-energy-dependent oscillations. A nonlinear generalization of Den Hartog's equal-peak method is proposed to ensure equal...

  11. Role of the Absorbing Area in Chaotic Synchronization

    Maistrenko, Yu.L.; Maistrenko, V.L.; Popovich, A.


    When two identical chaotic oscillators interact, one or more intervals of coupling parameters generally exist in which the synchronized state is weakly stable, and its basin of attraction is riddled with holes that are repelled from it. The paper discusses the role of the absorbing area...

  12. Angle- and Polarization-Insensitive Metamaterial Absorber using Via Array

    Lim, Daecheon; Lee, Dongju; Lim, Sungjoon


    In this paper, we propose an angle- and polarization-insensitive metamaterial absorber. We design a metamaterial unit cell that is based on a split ring cross resonator (SRCR). We observe that the absorption frequency and absorption ratio are insensitive to incident angles when a via array surrounds the SRR. We demonstrate the effect of the via array using full-wave simulations by comparing the absorptivity of the SRCR with and without the via array. Because of the symmetric geometry, we also realize polarization insensitivity. We build the proposed absorber on a printed-circuit-board with 30 × 30 unit cells, and we demonstrate its performance experimentally in free space. Under normal incidence, the fabricated absorber shows 99.6% absorptivity at 11.3 GHz for all polarization angles, while for oblique incidence, the fabricated absorber maintains an absorptivity higher than 90% for incident angles up to 70° and 60° for transverse magnetic (TM) and transverse electric (TE) modes, respectively. PMID:28000770

  13. Laser technology in solar absorber manufacturing; Laser punktet

    Berner, Joachim


    No other solar collector manufacturing stage is as fully automatic as absorber fabrication. Laser welding systems are well established in the market. In addition to welding machines, some manufacturers are also offering complete assembly lines for solar collector production. SONNE WIND and WAeRME presents technologies and manufacturers. (orig./AKB)

  14. Angle- and Polarization-Insensitive Metamaterial Absorber using Via Array

    Lim, Daecheon; Lee, Dongju; Lim, Sungjoon


    In this paper, we propose an angle- and polarization-insensitive metamaterial absorber. We design a metamaterial unit cell that is based on a split ring cross resonator (SRCR). We observe that the absorption frequency and absorption ratio are insensitive to incident angles when a via array surrounds the SRR. We demonstrate the effect of the via array using full-wave simulations by comparing the absorptivity of the SRCR with and without the via array. Because of the symmetric geometry, we also realize polarization insensitivity. We build the proposed absorber on a printed-circuit-board with 30 × 30 unit cells, and we demonstrate its performance experimentally in free space. Under normal incidence, the fabricated absorber shows 99.6% absorptivity at 11.3 GHz for all polarization angles, while for oblique incidence, the fabricated absorber maintains an absorptivity higher than 90% for incident angles up to 70° and 60° for transverse magnetic (TM) and transverse electric (TE) modes, respectively.

  15. Removal of trichlorobenzene using 'oxygen-enriched' highly active absorbent.

    Zhao, Yi; He, Peng; Zhang, Yu-Hai; Ma, Shuangchen


    Fly ash, industry lime and an additive, Ca(ClO2)2 (C) were used to prepare the 'oxygen-enriched' highly active absorbent (HAA). The influencing factors for removal of 1,2,4-trichlorobenzene (TCB) using this absorbent such as reaction temperature, simulating gas flow rate, oxygen content, etc. were studied in a self-designed reactor. The optimum experimental conditions of removing 1,2,4-TCB are that the content of an oxidizing additive in the absorbent is 3% (wt), simulating gas flow rate is 100 mL/min, reaction temperature is 250 degrees C, and the content of oxygen in simulating gas is 6%. The maximum removal efficiency is 81.71% in 10 mins. The absorption capacity of the absorbent is 0.000111 g/g. The reaction products were determined by gas chromatograph/mass spectrometer (GC/ MS), 2,6-Bis-[1,1-Dimethylethyl]-4-methyl-Phenol is considered to be the major intermediate product. The reaction route was revealed.

  16. Water-Structure Interactions on a Point Absorber

    Jakobsen, Morten Møller

    been the primary catalyst to more successful work later and may be helpful to others working in laboratory. The purpose of the experiments is to examine the wave and current induced loads on a floating point absorber (wave energy converter). Wave energy converters are used in ocean- or costal regions...

  17. Absorbed Dose Distribution in a Pulse Radiolysis Optical Cell

    Miller, Arne; McLaughlin, W. L.


    When a liquid solution in an optical cell is irradiated by an intense pulsed electron beam, it may be important in the chemical analysis of the solution to know the distribution of energy deposited throughout the cell. For the present work, absorbed dose distributions were measured by thin...

  18. New urea-absorbing polymers for artificial kidney machines

    Mueller, W. A.; Hsu, G. C.; Marsh, H. E., Jr.


    Etherified polymer is made from modified cellulose derivative which is reacted with periodate. It will absorb 2 grams of urea per 100 grams of polymer. Indications are that polymers could be used to help remove uremic wastes in artificial kidneys, or they could be administered orally as therapy for uremia.

  19. Polymers used to absorb fats and oils: A concept

    Marsh, H. E., Jr.


    One approach to problem of excessive oils and fats is to develop method by which oil is absorbed into solid mixture for elimination as solid waste. Materials proposed for these purposes are cross-linked (network) polymers that have high affinity for aliphatic substances, i. e., petroleum, animal, and vegetable oils.

  20. Atomic decay near a quantized medium of absorbing scatterers

    Suttorp, L.G.; van Wonderen, A.J.


    The decay of an excited atom in the presence of a medium that both scatters and absorbs radiation is studied with the help of a quantum-electrodynamical model. The medium is represented by a half-space filled with a randomly distributed set of non-overlapping spheres, which consist of a linear absor

  1. Fission life-time calculation using a complex absorbing potential

    Scamps Guillaume


    Full Text Available A comparison between the semi-classical approximation and the full quantum calculation with a complex absorbing potential is made with a model of the fission of 258Fm. The potential barrier is obtained with the constrained Skyrme HF+BCS theory. The life-time obtained by the two calculations agree with each other the difference being only by 25%.

  2. UV-absorbing compounds in subarctic herbarium bryophytes

    Huttunen, S. [Botany Division, Department of Biology, P.O. Box 3000, FIN-90 014 University of Oulu (Finland)]. E-mail:; Lappalainen, N.M. [Botany Division, Department of Biology, P.O. Box 3000, FIN-90 014 University of Oulu (Finland); Turunen, J. [Botany Division, Department of Biology, P.O. Box 3000, FIN-90 014 University of Oulu (Finland)


    The UV-B-absorbing compounds of herbarium specimens of 10 subarctic bryophyte species collected during the years 1926-1996 and available at the Botanical Museum, University of Oulu, were studied. We studied whether herbarium specimens reflect changes in the past radiation climate through their methanol-extractable compounds. The order of gametophytes based on the average amount of total compounds (sum of A{sub 280-320nm}) per mass from the lowest to the highest was Polytrichum commune, Pleurozium schreberi, Hylocomium splendens, Sphagnum angustifolium, Dicranum scoparium, Funaria hygrometrica, Sphagnum fuscum, Sphagnum warnstorfii, Sphagnum capillifolium and Polytrichastrum alpinum, and the amount of UV-B-absorbing compounds per specific surface area correlated with the summertime daily global radiation and latitude. P. alpinum, F. hygrometrica and three Sphagnum species seem to be good indicators for further studies. The amount of UV-B-absorbing compounds revealed no significant trends from the 1920s till the 1990s, with the exception of S. capillifolium, which showed a significant decreasing trend. - UV-B-absorbing compounds in subarctic herbarium bryophytes indicate the radiation climate of the collecting site and time.

  3. Metal-rich absorbers at high redshifts: abundance patterns

    Levshakov, S A; Molaro, P; Reimers, D; Hou, J L


    (Abbreviated) From six spectra of high-z QSOs, we select eleven metal-rich, Z>=Z_solar, and optically-thin to the ionizing radiation, N(HI)0, which supposes that the nitrogen enrichment occurs irregularly. In some cases, the lines of MgII 2796, 2803 appear to be shifted, probably as a result of an enhanced content of heavy isotopes 25Mg and 26Mg in the absorbing gas relative to the solar isotopic composition. Seven absorbers are characterized by low mean ionization parameter U, log U2 whereas all others are found at z ~= 1.8. Comparing the space number density of metal-rich absorbers with the comoving density of star-forming galaxies at z ~= 2, we estimate that the circumgalactic volume of each galaxy is populated by 10^7 - 10^8 such absorbers with total mass <=1/100th of the stellar galactic mass. Possible effects of high metal content on the peak values of star-forming and AGN activities at z~2 are discussed.

  4. Longitudinal metastructure bar with an active vibration absorber (Conference Presentation)

    Reichl, Katherine; Inman, Daniel J.


    This work addresses two issues in lightweight structural composites suitable for aerospace systems. The first is to add additional functionality to multifunctional composites and the second is to provide damping in structures that cover a wide range of frequencies and temperatures. Passive damping in all materials suffer from failing at certain temperature and in certain frequency ranges. The extreme environments often seen by aerospace structures provide high temperature, which is exactly where damping levels in structures reduce causing unacceptable vibrations. In addition, as loading frequencies decrease damping levels fall off, and many loads experienced by aerospace structures are low frequency. This work looks at the implementation of a control system to a longitudinal metastructure bar. A metastructure is a structure which has distributed vibration absorbers which provide passive damping to the system. The active control system will be implemented by adding piezoelectric materials to one of the absorbers to make the absorber active. The structure with the active vibration absorber will be compared to a structure of equal weight with no active components. Since the two comparison structures are of equal weight, the performance improvements are strictly due to the control system and not at the cost of additional weight.

  5. Superluminal pulse reflection from a weakly absorbing dielectric slab

    Wang, L G; Wang, Li-Gang; Zhu, Shi-Yao


    Group delay for a reflected light pulse from a weakly absorbing dielectric slab is theoretically investigated, and large negative group delay is found for weak absorption near a resonance of the slab ($Re(kd)=m\\pi$). The group delays for both the reflected and transmitted pulses will be saturated with the increase of the absorption.

  6. Molecular dynamic simulations of the water absorbency of hydrogels.

    Ou, Xiang; Han, Qiang; Dai, Hui-Hui; Wang, Jiong


    A polymer gel can imbibe solvent molecules through surface tension effect. When the solvent happens to be water, the gel can swell to a large extent and forms an aggregate called hydrogel. The large deformation caused by such swelling makes it difficult to study the behaviors of hydrogels. Currently, few molecular dynamic simulation works have been reported on the water absorbing mechanism of hydrogels. In this paper, we first use molecular dynamic simulation to study the water absorbing mechanism of hydrogels and propose a hydrogel-water interface model to study the water absorbency of the hydrogel surface. Also, the saturated water content and volume expansion rate of the hydrogel are investigated by building a hydrogel model with different cross-linking degree and by comparing the water absorption curves under different temperatures. The sample hydrogel model used consists of Polyethylene glycol diglycidyl ether (PEGDGE) as epoxy and the Jeffamine, poly-oxy-alkylene-amines, as curing agent. The conclusions obtained are useful for further investigation on PEGDGE/Jeffamine hydrogel. Moreover, the simulation methods, including hydrogel-water interface modeling, we first propose are also suitable to study the water absorbing mechanism of other hydrogels.

  7. Experimental realization of a terahertz all-dielectric metasurface absorber.

    Liu, Xinyu; Fan, Kebin; Shadrivov, Ilya V; Padilla, Willie J


    Metamaterial absorbers consisting of metal, metal-dielectric, or dielectric materials have been realized across much of the electromagnetic spectrum and have demonstrated novel properties and applications. However, most absorbers utilize metals and thus are limited in applicability due to their low melting point, high Ohmic loss and high thermal conductivity. Other approaches rely on large dielectric structures and / or a supporting dielectric substrate as a loss mechanism, thereby realizing large absorption volumes. Here we present a terahertz (THz) all dielectric metasurface absorber based on hybrid dielectric waveguide resonances. We tune the metasurface geometry in order to overlap electric and magnetic dipole resonances at the same frequency, thus achieving an experimental absorption of 97.5%. A simulated dielectric metasurface achieves a total absorption coefficient enhancement factor of FT=140, with a small absorption volume. Our experimental results are well described by theory and simulations and not limited to the THz range, but may be extended to microwave, infrared and optical frequencies. The concept of an all-dielectric metasurface absorber offers a new route for control of the emission and absorption of electromagnetic radiation from surfaces with potential applications in energy harvesting, imaging, and sensing.

  8. Absorbed Dose Distributions in Irradiated Plastic Tubing and Wire Insulation

    Miller, Arne; McLaughlin, W. L.


    Plastic tubing and wire insulation were simulated by radiochromic dye dosimeter films having electron absorbing properties similar to the materials of interest (polyethylene and PVC). A 400-keV electron accelerator was used to irradiate from 1, 2, 3 and 4 sides simulating possible industrial...

  9. Tests of absorbents and solidification techniques for oil wastes

    Lin, M.; MacKenzie, D. R.


    A representative of each of six classes of commonly used adsorbents was chosen for a series of tests. After reviewing ASTM and other related standard tests, uncomplicated procedures were developed for carrying out specific tests to determine absorbency for simulated oil waste and for water, under static and simulated transportation (repetitive shock) conditions. The tests were then applied to the six representative absorbents. Solidification tests were performed using these absorbents saturated with oil and loaded to 50% of saturation. The binders used were Portland I cement and Delaware Custom Material (DCM) cement shale silicate. Samples were checked for proper set, and the amounts of free liquid were measured. Another series of tests was performed on samples of simulated oil waste without absorbent, using Portland cement and DCM cement shale silicate. Samples were checked for proper set, free liquid was measured, and compressive strengths were determined. The state-of-the-art parameters were identified which satisfy NRC disposal criteria for solidified radioactive waste. The literature was reviewed for alternative methods of managing oil wastes. Conclusions are drawn on the relative utility of the various methods. 17 references, 3 tables.

  10. Absorbers in the Transactional Interpretation of Quantum Mechanics

    Boisvert, Jean-Sébastien; Marchildon, Louis


    The transactional interpretation of quantum mechanics, following the time-symmetric formulation of electrodynamics, uses retarded and advanced solutions of the Schrödinger equation and its complex conjugate to understand quantum phenomena by means of transactions. A transaction occurs between an emitter and a specific absorber when the emitter has received advanced waves from all possible absorbers. Advanced causation always raises the specter of paradoxes, and it must be addressed carefully. In particular, different devices involving contingent absorbers or various types of interaction-free measurements have been proposed as threatening the original version of the transactional interpretation. These proposals will be analyzed by examining in each case the configuration of absorbers and, in the special case of the so-called quantum liar experiment, by carefully following the development of retarded and advanced waves through the Mach-Zehnder interferometer. We will show that there is no need to resort to the hierarchy of transactions that some have proposed, and will argue that the transactional interpretation is consistent with the block-universe picture of time.

  11. Non-absorbable disaccharides versus placebo/no intervention and lactulose versus lactitol for the prevention and treatment of hepatic encephalopathy in people with cirrhosis

    Gluud, Lise Lotte; Vilstrup, Hendrik; Morgan, Marsha Y


    BACKGROUND: Non-absorbable disaccharides (lactulose and lactitol) are recommended as first-line treatment for hepatic encephalopathy. The previous (second) version of this review included 10 randomised clinical trials (RCTs) evaluating non-absorbable disaccharides versus placebo/no intervention...... and eight RCTs evaluating lactulose versus lactitol for people with cirrhosis and hepatic encephalopathy. The review found no evidence to either support or refute the use of the non-absorbable disaccharides and no differences between lactulose versus lactitol. OBJECTIVES: To assess the beneficial...... and harmful effects of i) non-absorbable disaccharides versus placebo/no intervention and ii) lactulose versus lactitol in people with cirrhosis and hepatic encephalopathy. SEARCH METHODS: We carried out electronic searches of the Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central...

  12. The development of national quality performance standards for disposable absorbent products for adult incontinence.

    Muller, Nancy; McInnis, Elaine


    Disposable absorbent products are widely used in inpatient care settings and in the community to manage adult urinary and fecal incontinence, but few product standards exist to help guide their production or optimal use. Increasing costs and reduced revenues have caused a number of states to evaluate absorbent product use among persons who receive care at home with the assistance of the Medicaid Waiver Program, further increasing concerns about the lack of product performance standards. To address these issues, the National Association For Continence (NAFC) formed a council of experts and key stakeholders with the objective of establishing national, independent quality performance standards for disposable absorbent products provided by states to Waiver Program recipients. The Council consisted of representatives from five purposefully selected states, technical directors from six nonwoven product manufacturers, an officer of the nonwoven manufactures trade association, a delegate from an academic nursing program and professional societies, a family caregiver, and a patient representative. Following a consensus method and guidelines for use, nine specific recommendations were developed, posted for public comment, and further refined. Final recommendations for product performance assessment include: rewet rate (a measure of a product's ability to withstand multiple incontinent episodes between changes), rate of acquisition (a measure of the speed at which urine is drawn away from the skin by a product, product retention capacity (a measure of a product's capacity to hold fluid without rewetting the skin), sizing options, absorbency levels, product safety, closure technology, breathable zones (a measure of the air permeability across a textile-like fabric at a controlled differential pressure), and elasticity. The Council also set values for and recommended four quantifiable parameters, and the testing methodology associated with each, to help consumers and states

  13. Fetal and maternal absorbed dose estimates for positron-emitting molecular imaging probes.

    Xie, Tianwu; Zaidi, Habib


    -generation computational models can be used for the assessment of radiation risks to pregnant women and the embryo/fetus undergoing PET/CT imaging procedures. This work also contributes to a better understanding of the absorbed dose distribution in the fetus. © 2014 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

  14. Intracellular labeling and quantification process by magnetic resonance imaging using iron oxide magnetic nanoparticles in rat C6 glioma cell line; Marcacao intracelular e processo de quantificacao por imagem por ressonancia magnetica utilizando nanoparticulas magneticas de oxido de ferro em celulas da linhagem C6 de glioma de rato

    Mamani, Javier Bustamante; Pavon, Lorena Favaro; Sibov, Tatiana Tais; Rossan, Fabiana; Silveira, Paulo Henrique; Cardenas, Walter Humberto; Gamarra, Lionel Fernel, E-mail: [Instituto do Cerebro - InCe, Hospital Israelita Albert Einstein - HIAE, Sao Paulo, SP (Brazil); Miyaki, Liza Aya Mabuchi [Faculdade de Enfermagem, Hospital Israelita Albert Einstein - HIAE, Sao Paulo, SP (Brazil); Amaro Junior, Edson [Departamento de Diagnostico por Imagem e Instituto do Cerebro - InCe, Hospital Israelita Albert Einstein - HIAE, Sao Paulo, SP (Brazil)


    Objective: To assess intracellular labeling and quantification by magnetic resonance imaging using iron oxide magnetic nanoparticles coated with biocompatible materials in rat C6 glioma cells in vitro. These methods will provide direction for future trials of tumor induction in vivo as well as possible magnetic hyperthermia applications. Methods: Aminosilane, dextran, polyvinyl alcohol, and starch-coated magnetic nanoparticles were used in the qualitative assessment of C6 cell labeling via light microscopy. The influence of the transfection agent poly-L-lysine on cellular uptake was examined. The quantification process was performed by relaxometry analysis in T{sub 1} and T{sub 2} weighted phantom images. Results: Light microscopy revealed that the aminosilane-coated magnetic nanoparticles alone or complexed with poly-L-lysine showed higher cellular uptake than did the uncoated magnetic particles. The relaxactivities of the aminosilane-coated magnetic nanoparticles with a hydrodynamic diameter of 50nm to a 3-T field were r{sub 1}=(6.1 +- 0.3) x10{sup -5} ms{sup -1}mL/{mu}g, r{sub 2}=(5.3 +- 0.1) x 10{sup -4} ms{sup -1}mL/{mu}g, with a ratio of r{sub 2} / r{sub 1}{approx_equal} 9. The iron uptake in the cells was calculated by analyzing the relaxation rates (R{sub 1}and R{sub 2}) using a mathematical relationship. Conclusions: C6 glioma cells have a high uptake efficiency for aminosilane-coated magnetic nanoparticles complexed with the transfection agent poly-L-lysine. The large ratio r{sub 2} / r{sub 1}{approx_equal} 9 indicates that these magnetic nanoparticles are ideal for quantification by magnetic resonance imaging with T{sub 2}-weighted imaging techniques. (author)

  15. Absorbed dose to water reference dosimetry using solid phantoms in the context of absorbed-dose protocols.

    Seuntjens, Jan; Olivares, Marina; Evans, Michael; Podgorsak, Ervin


    For reasons of phantom material reproducibility, the absorbed dose protocols of the American Association of Physicists in Medicine (AAPM) (TG-51) and the International Atomic Energy Agency (IAEA) (TRS-398) have made the use of liquid water as a phantom material for reference dosimetry mandatory. In this work we provide a formal framework for the measurement of absorbed dose to water using ionization chambers calibrated in terms of absorbed dose to water but irradiated in solid phantoms. Such a framework is useful when there is a desire to put dose measurements using solid phantoms on an absolute basis. Putting solid phantom measurements on an absolute basis has distinct advantages in verification measurements and quality assurance. We introduce a phantom dose conversion factor that converts a measurement made in a solid phantom and analyzed using an absorbed dose calibration protocol into absorbed dose to water under reference conditions. We provide techniques to measure and calculate the dose transfer from solid phantom to water. For an Exradin A12 ionization chamber, we measured and calculated the phantom dose conversion factor for six Solid Water phantoms and for a single Lucite phantom for photon energies between 60Co and 18 MV photons. For Solid Water of certified grade, the difference between measured and calculated factors varied between 0.0% and 0.7% with the average dose conversion factor being low by 0.4% compared with the calculation whereas for Lucite, the agreement was within 0.2% for the one phantom examined. The composition of commercial plastic phantoms and their homogeneity may not always be reproducible and consistent with assumed composition. By comparing measured and calculated phantom conversion factors, our work provides methods to verify the consistency of a given plastic for the purpose of clinical reference dosimetry.

  16. Potential climatic effects of light absorbing particles over the Third Pole regions

    Ji, Zhenming; Kang, Shichang


    Light absorbing particles (LAPs) have important impact on regional climate over the Third Pole regions. Carbonaceous and mineral aerosols, which are considered as the anthropogenic and natural sources respectively, can absorb and scatter incident solar radiation in the atmosphere. Meanwhile, LAPs deposition in snow/ice can also change the surface albedo, resulting in perturbations in the surface radiation balance. However, most studies that have made quantitative assessments of the climatic effect of LAPs over the Third Pole regions did not consider the impact of dust on snow/ice at the surface. In this study, a regional climate model RegCM4.3.4 (Regional Climate Model version 4.3.4) coupled with an aerosol-snow/ice feedback module was used to investigate the emission, distribution, and deposition of carbonaceous and dust aerosols. The study was focused on the two issues: 1) the evaluation of model performance; 2) the assessment of climatic effects induced by carbonaceous and mineral dust aerosols, respectively.

  17. Measurement of absorbed dose and proposed radiation exposure level

    Hasegawa, Takayuki; Koizumi, Masayuki; Furukawa, Tomo [Tokai Univ., Isehara, Kanagawa (Japan). Hospital


    Absorbed dose was measured in clinical X-ray examinations using thermoluminescence dosimeter (TLD). Moreover, we distributed the levels of radiation exposure into 3 classes. The presumed dose of the internal organs, e.g., uterus dose, was computed to depth doses with a surface dose. This information provides a prediction of the influence of radiation, and the examination can be performed with the informed consent of the patient. Moreover, we examined the distribution of the level of absorbed dose. We proposed two kinds of radiation exposure level, one to the fetus in a pregnant woman and a general level of radiation exposure that is not applied to pregnant women. The levels were as follows: 0.5 mGy and 100 mGy were considered the boundaries for fetal radiation exposure in a pregnant woman, and 200 mGy and 3 Gy were considered the boundaries for the general level of radiation exposure (excluding pregnant women). (author)



    To achieve the dual demand of resisting violent impact and attenuating vibration in vibration-impact-safety of protection for precision equipment such as MEMS packaging system, a theoretical mathematical model of multi-medium coupling shock absorber is presented. The coupling of quadratic damping, linear damping, Coulomb damping and nonlinear spring are considered in the model. The approximate theoretical calculating formulae are deduced by introducing transformation-tactics. The contrasts between the analytical results and numerical integration results are developed. The resisting impact characteristics of the model are also analyzed in progress. In the meantime,the optimum model of the parameters matching selection for design of the shock absorber is built.The example design is illustrated to confirm the validity of the modeling method and the theoretical solution.

  19. Seeking new growth hotspots in absorbing foreign direct investment



    In recent years, China’s service industries have absorbed an increasing amount of foreign direct investment (FDI); foreign investors have taken wholly foreign-owned enterprise (WFOE) as the most preferred vehicle of making investment in China; free ports have become a major source of FDI inflows to China; China’s FDI inflows as a percentage of global FDI inflows have been in decline. In the export-oriented or import-substitution manufacturing industries, China still needs to vigorously absorb FDI in the future. In addition, China should continue opening its infrastructure and social service industries. It is therefore imperative to further improve the institutional and policy environment for foreign investment utilization.

  20. Large-area, wide-angle, spectrally selective plasmonic absorber

    Wu, Chihhui; John, Jeremy; Milder, Andrew; Zollars, Byron; Savoy, Steve; Shvets, Gennady


    A simple metamaterial-based wide-angle plasmonic absorber is introduced, fabricated, and experimentally characterized using angle-resolved infrared spectroscopy. The metamaterials are prepared by nano-imprint lithography, an attractive low-cost technology for making large-area samples. The matching of the metamaterial's impedance to that of vacuum is responsible for the observed spectrally selective "perfect" absorption of infrared light. The impedance is theoretically calculated in the single-resonance approximation, and the responsible resonance is identified as a short-range surface plasmon. The spectral position of the absorption peak (which is as high as 95%) is experimentally shown to be controlled by the metamaterial's dimensions. The persistence of "perfect" absorption with variable metamaterial parameters is theoretically explained. The wide-angle nature of the absorber can be utilized for sub-diffraction-scale infrared pixels exhibiting spectrally selective absorption/emissivity.

  1. Water heating solar system using collector with polycarbonate absorber surface

    Souza, Luiz Guilherme Meira de; Sodre, Dilton; Cavalcanti, Eduardo Jose Cidade; Souza, Luiz Guilherme Vieira Meira de; Mendes, Jose Ubiragi de Lima [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil)], e-mails:,,


    It is presented s solar collector to be used in a heating water for bath system, whose main characteristics are low cost and easy fabrication and assembly processes. The collector absorber surface consists of a polycarbonate plate with an area of 1.5 m{sup 2}. The water inlet and outlet are made of PVC 50mm, and were coupled to a 6mm thick polycarbonate plate using fiberglass resin. A 200 liters thermal reservoir will be used. This reservoir is also alternative. The absorber heating system works under thermo-siphon regimen. Thermal parameters will be evaluated to prove the feasibility of the studied solar heating system to obtain bath water for a four people family. (author)

  2. Large-scale nanostructured low-temperature solar selective absorber.

    Chi, Kequn; Yang, Liu; Liu, Zhaolang; Gao, PingQi; Ye, Jichun; He, Sailing


    A large-scale nanostructured low-temperature solar selective absorber is demonstrated experimentally. It consists of a silicon dioxide thin film coating on a rough refractory tantalum substrate, fabricated based simply on self-assembled, closely packed polystyrene nanospheres. Because of the strong light harvesting of the surface nanopatterns and constructive interference within the top silicon dioxide coating, our absorber has a much higher solar absorption (0.84) than its planar counterpart (0.78). Though its absorption is lower than that of commercial black paint with ultra-broad absorption, the greatly suppressed absorption/emission in the long range still enables a superior heat accumulation. The working temperature is as high as 196.3°C under 7-sun solar illumination in ambient conditions-much higher than those achieved by the two comparables.

  3. Multimodal tuned dynamic absorber for split Stirling linear cryocooler

    Veprik, Alexander; Tuito, Avi


    Low size, weight, power and price split Stirling linear cryocooler usually comprises electro-dynamically driven compressor and pneumatically driven expander which are side-by-side fixedly mounted upon the common frame and interconnected by the configurable transfer line. Vibration export produced by such a cryocooler comprises of a pair of tonal forces, the frequency of which essentially equals fixed driving frequency. In vibration sensitive applications, this may result in excessive angular line of sight jitter and translational defocusing affecting the image quality. The authors present Multimodal Tuned Dynamic Absorber, having one translational and two tilting modes essentially tuned to the driving frequency. Dynamic analysis shows that the dynamic reactions (force and moment) produced by such a dynamic absorber are capable of simultaneous attenuation of translational and tilting components of cryocooler induced vibration. The authors reveal the preferable design, the method of fine tuning and outcomes of numerical simulation on attainable performance.

  4. Analysis of heat and mass transfer on helical absorber

    Kwon, O.K.; Kim, S.C.; Yun, J.H. [Korea Institute of Industrial Technology, Chonan (Korea); Lim, J.K.; Yoon, J.I. [Pukyong National University, Pusan (Korea)


    The absorption of vapor involves simultaneous heat and mass transfer in the vapor/liquid system. In this paper, a numerical study for vapor absorption process into LiBr-H{sub 2}O solution film flowing over helical absorber has been carried out. Axisymmetric cylindrical coordinate system was adopted to model the helical tube and the transport equations were solved by the finite volume method. The effects of operating conditions, such as the cooling water temperature, the system pressure, the film Reynolds number and the solution inlet concentration have been investigated in view of the absorption mass flux and the total absorption rate. The results for the temperature and concentration profiles, as well as the local absorption mass flux at the helical absorber are presented. It is shown that solution inlet concentration affected other than operation conditions for a mass flux. (author). 10 refs., 14 figs., 2 tabs.

  5. Photon spectrum and absorbed dose in brain tumor

    Silva S, A. [General Electric Healthcare, Antonio Dovali Jaime 70, Torre A 3er. piso, Col. Santa Fe, 01210 Mexico D. F. (Mexico); Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas, Zac. (Mexico); Rivera M, T. [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Av. Legaria No. 694, 11500 Mexico D. F. (Mexico)


    Using Monte Carlo methods a BOMAB phantom inside a treatment hall with a brain tumor nearby the pituitary gland was treated with photons produced by a Varian 6 MV linac. The photon spectrum and the absorbed dose were calculated in the tumor, pituitary gland and the head. The treatment beam was collimated to illuminate only the tumor volume; however photons were noticed in the gland. Photon fluence reaching the tumor is 78.1 times larger than the fluence in the pituitary gland, on the other hand the absorbed dose in the tumor is 188 times larger than the dose in the gland because photons that reach the pituitary gland are scattered, by the head and the tumor, through Compton effect. (Author)

  6. Refractory absorber/emitter using monolayer of ceramic microparticles

    Dyachenko, P. N.; do Rosário, J. J.; Leib, E. W.; Petrov, A. Y.; Störmer, M.; Weller, H.; Vossmeyer, T.; Schneider, G. A.; Eich, M.


    We present a self-assembled refractory absorber/emitter without the necessity to structure the metallic surface itself, still retaining the feature of tailored optical properties for visible light emission and thermophotovoltaic (TPV) applications. We have demonstrated theoretically and experimentally that monolayers of zirconium dioxide (ZrO2) microparticles on a tungsten layer can be used as large area, efficient and thermally stable selective absorbers/emitters. The band edge of the absorption is based on critically coupled microsphere resonances. It can be tuned from visible to near-infrared range by varying the diameter of the microparticles. We demonstrated the optical functionality of the structure after annealing up to temperatures of 1000°C under vacuum conditions. In particular it opens up the route towards high efficiency TPV systems with emission matched to the photovoltaic cell.

  7. Humidity buffering of interior spaces by porous, absorbent insulation

    Padfield, Tim


    Thermal insulation made from wool will have a detectable, but small, moderating influence onvariation in the indoor relative humidity in a house with less than half an air change per hour andwith porous wall surfaces, such as paper, limewash or silicate paint.Water vapour distributes itself fairly...... to practical insignificance.Absorbent insulation will only have a useful influence on the indoor climate if the entire wall isredesigned to give a much more porous structure. This development would conflict with thecustom of putting a vapour barrier or vapour retarder close to the inside surface of a wall....... A morepractical way of moderating the indoor relative humidity would be to use an absorbent interiorfinish instead of the customary gypsum board. The excellent performance of end grain wood as aninterior finish is shown for comparison.The experiments reported here show the influence on the daily variation...

  8. Tachyons and the Wheeler-Feynman Absorber Theory

    Tomaschitz, R


    The Proca equation with negative mass-square is studied in a refractive and absorptive spacetime. The generation of superluminal radiation fields by subluminal currents is discussed. The possibility of time-symmetric wave propagation is analysed in the context of the Wheeler-Feynman absorber theory; it is shown how advanced modes of the Proca field can be turned into retarded ones in a permeable spacetime capable of producing an absorber field. A microscopic oscillator model for the permeability is suggested. Tachyonic Lienard-Wiechert potentials are studied and strictly causal retarded wave solutions are obtained. Energy transfer by superluminal radiation is discussed, and explicit formulae for the spectral energy density and intensity are derived. Superluminal radiation fields generated by classical damped oscillators carrying tachyonic charge are investigated, including the tachyonic analogue to Thomson and Rayleigh cross sections. The Maxwell equations for negative mass-square are derived, their non-local...

  9. Some comments on the concept of absorbed dose

    Alvarez R, J.T. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)


    The main physical quantity for the evaluation of the induced effects by radiation ionizing is absorbed dose. ICRU report 51 defines this concept as quantity d{epsilon} divided by dm, where d{epsilon} is the mean energy imparted by radiation ionizing to matter of mass dm. However, nothing is said about the average operation concerning the stochastic energy imparted {epsilon}. Nevertheless, because considers the sum of all changes of rest mass of the involved nuclei and elementary particles in all interactions which occur within the mass (i.e. nuclear reactions and transformations of elementary particles), the average operation can not be done with an equilibrium statistical operator, rather, this has to be defined with a non-equilibrium statistical operator, therefore, absorbed dose is a function dependent on time. Furthermore, we present a discussion to clarify the equilibrium radiation and charged particle equilibrium within the context of thermodynamic equilibrium. (Author)

  10. A Pair of Light Emitting Diodes for Absorbance Measurement

    Shin, Dongyong; Eom, Inyong [Catholic Univ. of Daegu, Gyeongsan (Korea, Republic of)


    Two same wavelength LEDs (i. e. an emitter LED and a detector LED, respectively) were successfully used to measure absorbance of BTB solution. A linear calibration with r-squared value of 0.9945 was achieved. 0.03 μM of LOD was observed with a noise level of 2 Χ 10{sup -4} absorbance unit. We are now examining relative sensitivities of different LEDs with distinct wavelength. In the future, building a spectrophotometer equipped with LEDs is quite interesting both in scientifically and pedagogically (i. e. undergraduate lab course). Light emitting diodes (LEDs) have a semiconductor chip (∼1 mm{sup 2} area) mounted on a concave mirror and emit narrow band of wavelengths when forward biased. LEDs have been widely used in many fields. Conventional light bulbs are being replaced by LED bulbs.

  11. Stiffness control of magnetorheological gels for adaptive tunable vibration absorber

    Kim, Hyun Kee; Kim, Hye Shin; Kim, Young-Keun


    In this study, a stiffness feedback control system for magnetorheological (MR) gel—a smart material of variable stiffness—is proposed, toward the design of a tunable vibration absorber that can adaptively tune to a time varying disturbance in real time. A PID controller was designed to track the required stiffness of the MR gel by controlling the magnitude of the target external magnetic field pervading the MR gel. This paper proposes a novel magnetic field generator that could produce a variable magnetic field with low energy consumption. The performance of the MR gel stiffness control was validated through experiments that showed the MR gel absorber system could be automatically tuned from 56 Hz to 67 Hz under a field of 100 mT to minimize the vibration of the primary system.

  12. Microwave absorbing properties and magnetic properties of different carbon nanotubes


    The microwave absorbing properties and magnetic properties of as-grown Fe-filled carbon nanotubes (CNTs), annealed Fe-filled CNTs, and multi-walled CNTs were studied. Vibrating sample magnetometer results showed that the annealed Fe-filled CNTs have the weakest coercivity and strongest saturation magnetization among the three types CNTs, due to the presence of more ferromagnetic α-Fe nanowires. After annealing, the values increased to 291.0 Oe and 28.0 emu/g and the samples showed excellent microwave absorbing properties. The reflection loss was over 5 dB between 11.6 GHz and 18 GHz with a maximum value of 10.8 dB for annealed Fe-filled CNTs (1.1 wt%)/epoxy composite.

  13. Application Of Shape Memory Alloy In Harvesto-Absorber System

    Kęcik Krzysztof


    Full Text Available This paper presents a conception of the harvester-absorber system consisting of two parts. The first is the pendulum attached to the main system (oscillator, which is suspended on the linear damper and the nonlinear spring made of shape memory alloy. The spring is modelled as a polynomial function based on Landau–Ginzburg theory of phase transitions (similar as ferroelectric and ferromagnets. The obtained results show, that SMA element can increase harvesting energy level, while the absorber effect can be impaired (but not loss. Additionally, introducing SMA element causes changes in dynamics, introduces a new unstable solutions and bifurcations. The analysis was done by classical integration and continuation solution methods.

  14. Ultrafast pulse generation with black phosphorus solution saturable absorber

    Li, Lu; Wang, Yonggang; Wang, Xi


    The study presents the mode-locked Er-doped fiber (EDF) laser with a black phosphorus (BP) solution saturable absorber (SSA). The saturable absorber (SA) is fabricated based on a D-shaped fiber (DF) embedded in BP nanosheets N-Methylpyrrolidone solution. Such a BP solution method has the virtues of good antioxidant capacity, high heat dissipation and high damage threshold. This kind of SA shows a modulation depth of 7.75% and a nonsaturable loss of 10%. By employing the EDF-BP SSA, a repetition rate of 15.2 MHz mode-locked fiber laser is achieved. The pulse duration is 580 fs and the signal-to-noise ratio is 65 dB. The results indicate that the DF-BP solution can work as a potential SA for ultrafast nonlinear optics.

  15. Absorption enhancement of a dual-band metamaterial absorber

    Zhong, Min; Han, Gui Ming; Liu, Shui Jie; Xu, Bang Li; Wang, Jie; Huang, Hua Qing


    In this paper, we propose and fabricate a dual-band metamaterial absorber in 6-24 THz region. Electric field distribution reveal that the first absorption band is obtained from localized surface plasmon (LSP) modes which are excited both on inside and outside edges of each circular-patterned metal-dielectric stack, while the second absorption band is excited by LSP modes on outside edges of each stack. Measured results indicate that the absorption band width can be tuned by increasing the radius of circular-patterned layers or reducing the thickness of dielectric spacing layers. Moreover, the designed dual-band metamaterial absorber is independent on circular-patterned dielectric layer combinations.

  16. Resonance scattering of canonical elastic shells in absorbing fluid medium

    ZHUO Linkai; FAN Jun; TANG Weilin


    Resonance scattering of elastic spherical shell and cylindrical shell while the sur-rounding fluid medium has absorption is studied. The normal mode solution derived using exact elastic theory and the separation of variables is still applicable. However, the scattering form function has to be modified for the absorbing medium, otherwise the unreasonable resul twould be obtained. The backscattering form function in the absorbing medium is redefined, and the form function of elastic spherical and cylindrical shell with vacuum or solid matter filled is calculated in various absorption conditions. The results show that the absorption of surround-ing fluid leads to notable attenuation of the coincidence resonances in the mid-frequency, but it has a little in fluence on the low-frequency resonance scattering induced by the filler inside the shell.

  17. Research on the Relationship Between Absorbed Slack and Technology Innovation

    刘益; 方润生


    This paper divides the absorbed slack into dispersed slack and combined slack from the point of view of control right and analyzes the affection these two kinds of slacks have on the innovation. This research build a model of structural equation reflecting the relationship among the slack, absorbed capacity and innovation and proved this model with the data get from 607 enterprises by questionnaire. The result indicates that the dispersed slack and combined slack have positive relationship respectively with product innovation and process innovation and different slacks have some matching relationship with different absorptive capacities, which can result in different innovative output. This shows that the slack in Chinese enterprises can also promote the innovative output just like the western enterprises; so reducing the staff according to simple principles perhaps cannot be the most efficient way to improve the effectiveness in Chinese enterprises.

  18. Microwave absorbing properties and magnetic properties of different carbon nanotubes

    GUI XuChun; WANG KunLin; WEI JinQuan; L(U) RuiTao; SHU QinKe; JIA Yi; WANG Chen; ZHU HongWei; WU DeHai


    The microwave absorbing properties and magnetic properties of as-grown Fe-filled carbon nanotubes (CNTs), annealed Fe-filled CNTs, and multi-walled CNTs were studied. Vibrating sample magnetometer results showed that the annealed Fe-filled CNTs have the weakest coercivity and strongest saturation magnetization among the three types CNTs, due to the presence of more ferromagnetic α-Fe nanowires.After annealing, the values increased to 291.00e and 28.0 emu/g and the samples showed excellent microwave absorbing properties. The reflection loss was over 5 dB between 11.6 GHz and 18 GHz with a maximum value of 10.8 dB for annealed Fe-filled CNTs (1.1 wt%)/epoxy composite.

  19. Hysteresis of transient populations in absorbing-state systems

    Kapitanchuk, Oleksiy L.; Marchenko, Oleksij M.; Teslenko, Victor I.


    A nonequilibrium density matrix theory is used in order to explicitly describe the hysteresis interrelation between populations of nonstationary states in an absorbing multi-stage chain system in the one-particle approximation. As an illustrative example, we restrict ourselves to consideration of the 3-stage absorbing case for which we identify three types of the hysteresis; that is, the causal time dependent hysteresis with leaf-like and triangle-like closed loops, the hidden hysteresis with broken-line loops and the true hysteresis with open loops. Furthermore, we observe a common critical threshold for the hysteresis types and ascertain a reciprocal correspondence of this threshold as between the types as well with the experiment.

  20. Single-photon absorber based on strongly interacting Rydberg atoms

    Tresp, Christoph; Mirgorodskiy, Ivan; Gorniaczyk, Hannes; Paris-Mandoki, Asaf; Hofferberth, Sebastian


    Removing exactly one photon from an arbitrary input pulse is an elementary operation in quantum optics and enables applications in quantum information processing and quantum simulation. Here we demonstrate a deterministic single-photon absorber based on the saturation of an optically thick free-space medium by a single photon due to Rydberg blockade. Single-photon subtraction adds a new component to the Rydberg quantum optics toolbox, which already contains photonic logic building-blocks such as single-photon sources, switches, transistors, and conditional $\\pi$-phase shifts. Our approach is scalable to multiple cascaded absorbers, essential for preparation of non-classical light states for quantum information and metrology applications, and, in combination with the single-photon transistor, high-fidelity number-resolved photon detection.

  1. Online identification of active absorbers in automotive vibration control

    Buttelmann, M.; Lohmann, B.; Vinogradski, M.; Nedeljkovic, N. [Bremen Univ. (Germany). Inst. fuer Automatisierungstechnik; Marienfeld, P. [ContiTech Vibration Control GmbH, Hannover (Germany); Svaricek, F. [Continental Gummi-Werke AG, Hannover (Germany)


    In the past, engine-related noise and vibration in the vehicle cabin was exclusively reduced by passive absorption. Today, modern actuators and control systems make an active noise reduction possible by introducing counteracting vibration at 180 degrees phase lag. Within a cooperation of the Institute of Automation Systems and Continental AG, an approach using active absorbers at the engine mounts is investigated. As the dynamic behaviour of the active absorbers and other elements in the secondary path are time-variant (depending on temperature, age and other factors), an online identification is carried out. By this, the implemented feedforward control strategy is supported on a precise and frequently updated model of the secondary path. The chosen approaches to online and offline identification are presented together with first results achieved in online identification and with the overall control system. (orig.)

  2. [Shaping of electron radiation fields using homogeneous absorbent materials].

    Eichhorn, M; Reis, A; Kraft, M


    Proof of shielding and forming by absorbers was done in water phantom dosimetrically. Alterations of isodose course were measured in dependence of primary energy, as well as of thickness and density of the absorber materials. Piacryl or aluminium are not suitable for forming of irregular electron fields. They only effect a reduction of therapeutic range. For primary energies of 10.0 less than or equal to MeV less than or equal to E0- less than or equal to 20.0 MeV lead rubber and wood metal are to recommended in a thickness of less than or equal to 10 mm or less than or equal to 8 mm respectively.

  3. Preparation and Property of the Water Absorbent Hybrid Resin


    @@ Water absorption material has been attracted much more attention for its wide use in soil and water conservation, agriculture, etc. But this material will actually apply in agriculture, soil and water conservation only when it is cheap enough. Pulp fiber and starch to prepare high absorbing-water resin is a good method for decreasing the cost [1,2]. However, it still has a long way to turn it into reality. Now the montmorillonite is widely used in preparing nanocomposites [3]. But used it in preparing absorbing-water resin has little report. In this article the water absorption hybrid resin has been prepared by one step intercalation polymerization method. In the process of intercalation the partly neutralization acrylic acid and urea have been used as intercalating reagent. Beside that, the urea also has been used as cross-linking agent.

  4. Preparation and Property of the Water Absorbent Hybrid Resin

    WANG; YunPu


    Water absorption material has been attracted much more attention for its wide use in soil and water conservation, agriculture, etc. But this material will actually apply in agriculture, soil and water conservation only when it is cheap enough. Pulp fiber and starch to prepare high absorbing-water resin is a good method for decreasing the cost [1,2]. However, it still has a long way to turn it into reality.  Now the montmorillonite is widely used in preparing nanocomposites [3]. But used it in preparing absorbing-water resin has little report. In this article the water absorption hybrid resin has been prepared by one step intercalation polymerization method. In the process of intercalation the partly neutralization acrylic acid and urea have been used as intercalating reagent. Beside that, the urea also has been used as cross-linking agent.   ……

  5. Sensors of absorbed dose of ionizing radiation based on mosfet

    Perevertaylo V. L.


    Full Text Available The requirements to technology and design of p-channel and n-channel MOS transistors with a thick oxide layer designed for use in the capacity of integral dosimeters of absorbed dose of ionizing radiation are defined. The technology of radiation-sensitive MOS transistors with a thick oxide in the p-channel and n-channel version is created.

  6. Tailored Buckling Microlattices as Reusable Light-Weight Shock Absorbers.

    Frenzel, Tobias; Findeisen, Claudio; Kadic, Muamer; Gumbsch, Peter; Wegener, Martin


    Structures and materials absorbing mechanical (shock) energy commonly exploit either viscoelasticity or destructive modifications. Based on a class of uniaxial light-weight geometrically nonlinear mechanical microlattices and using buckling of inner elements, either a sequence of snap-ins followed by irreversible hysteretic - yet repeatable - self-recovery or multistability is achieved, enabling programmable behavior. Proof-of-principle experiments on three-dimensional polymer microstructures are presented.

  7. Theoretical Research of Magnetorheological Shock Absorber Damping Force

    Andrius Klevinskis


    Full Text Available In the article an overview of magnetorheological shock absorbertypes is presented, theoretical calculations of heat dispersion,magnetic field strength produced by shock absorber as well asmaximum power of electromagnet are provided. The article alsoprovides device damping force in line with a change of devicetemperature. In the end of the research the results of experimentare presented in the graph format as well as the conclusions.

  8. Flexible metamaterial absorbers for stealth applications at terahertz frequencies

    Iwaszczuk, Krzysztof; Strikwerda, Andrew; Fan, K.


    We have wrapped metallic cylinders with strongly absorbing metamaterials. These resonant structures, which are patterned on flexible substrates, smoothly coat the cylinder and give it an electromagnetic response designed to minimize its radar cross section. We compare the normal-incidence, small...... frequency of 0.87 THz. In addition we discuss the effect of finite sample dimensions and the spatial dependence of the reflection spectrum of the metamaterial. (C)2011 Optical Society of America...

  9. Absorbed radiation by various tissues during simulated endodontic radiography

    Torabinejad, M.; Danforth, R.; Andrews, K.; Chan, C.


    The amount of absorbed radiation by various organs was determined by placing lithium fluoride thermoluminescent chip dosimeters at selected anatomical sites in and on a human-like X-ray phantom and exposing them to radiation at 70- and 90-kV X-ray peaks during simulated endodontic radiography. The mean exposure dose was determined for each anatomical site. The results show that endodontic X-ray doses received by patients are low when compared with other radiographic procedures.

  10. Shock Absorbers Save Structures and Lives during Earthquakes


    With NASA funding, North Tonawanda, New York-based Taylor Devices Inc. developed fluidic shock absorbers to safely remove the fuel and electrical connectors from the space shuttles during launch. The company is now employing the technology as seismic dampers to protect structures from earthquakes. To date, 550 buildings and bridges have the dampers, and not a single one has suffered damage in the wake of an earthquake.

  11. Non-self-absorbing materials for Luminescent Solar Concentrators (LSC)

    Saraidarov, T.; Levchenko, V.; Grabowska, A.; Borowicz, P.; Reisfeld, R.


    The diheptyl-bipyridyl-diol, as a non-self-absorbing fluorescent compound characterized by a large separation between absorption and fluorescence bands, has been incorporated in polyvinyl-butyral film. Steady state luminescence and lifetime were measured. An increase of luminescence intensity by about 34% in the presence of silver nanoparticles was observed. No appreciable changes were found in the corresponding lifetimes. The system is proposed as a potential candidate for increasing the LSC efficiency.

  12. Wheeler-Feynman Absorbers on the Light Horizon

    Lear, C. W.


    Early Wheeler-Feynman absorber theories invoke both retarded and advanced electromagnetic waves for photon emission and absorption in order to remove problems involving lack of radiative damping during electron acceleration. Subsequent inquiries have suggested that only certain cosmologies would allow such a retarded-advanced wave mechanism to exist. These include quasi-steady state cosmologies and exclude flat, expanding Friedman-type cosmologies. Key to the exclusion process is a diminishin...

  13. On the dual symmetry between absorbing and amplifying random media

    S Anantha Ramakrishna


    We re-examine the dual symmetry between absorbing and amplifying random media. By analysing the physically allowed choice of the sign of the square root to determine the complex wave vector in a medium, we draw a broad set of conclusions that enables us to resolve the apparent paradox of the dual symmetry and also to anticipate the large local electromagnetic field enhancements in amplifying random media.

  14. An absorbing phase transition from a structured active particle phase

    Lopez, Cristobal [Instituto Mediterraneo de Estudios Avanzados IMEDEA (CSIC-UIB), Campus de la Universidad de las Islas Baleares, E-07122 Palma de Mallorca (Spain); Ramos, Francisco [Departamento de Electromagnetismo y Fisica de la Materia and Instituto de Fisica Teorica y Computacional Carlos I, Facultad de Ciencias, Universidad de Granada, 18071 Granada (Spain); Hernandez-GarcIa, Emilio [Instituto Mediterraneo de Estudios Avanzados IMEDEA (CSIC-UIB), Campus de la Universidad de las Islas Baleares, E-07122 Palma de Mallorca (Spain)


    In this work we study the absorbing state phase transition of a recently introduced model for interacting particles with neighbourhood-dependent reproduction rates. The novelty of the transition is that as soon as the active phase is reached by increasing a control parameter a periodically arranged structure of particle clusters appears. A numerical study in one and two dimensions shows that the system falls into the directed percolation universality class.

  15. Numerical Modeling of a Wave Energy Point Absorber

    Hernandez, Lorenzo Banos; Frigaard, Peter; Kirkegaard, Poul Henning


    The present study deals with numerical modelling of the Wave Star Energy WSE device. Hereby, linear potential theory is applied via a BEM code on the wave hydrodynamics exciting the floaters. Time and frequency domain solutions of the floater response are determined for regular and irregular seas....... Furthermore, these results are used to estimate the power and the energy absorbed by a single oscillating floater. Finally, a latching control strategy is analysed in open-loop configuration for energy maximization....

  16. Acoustic radiation force and torque on an absorbing particle

    Silva, Glauber T


    Exact formulas of the radiation force and torque exerted on an absorbing particle in the Rayleigh scattering limit caused by an arbitrary harmonic acoustic wave are presented. They are used to analyze the trapping conditions by a single-beam acoustical tweezer based on a spherically focused ultrasound beam. Results reveal that particle's absorption has a pivotal role in single-beam trapping. Furthermore, we obtain the radiation torque induced by a Bessel beam in an on-axis particle.

  17. Reflection and absorption of millimeter waves by thin absorbing films.

    Alekseev, S I; Ziskin, M C


    Reflection, transmission, and absorption of mm-waves by thin absorbing films were determined at two therapeutic frequencies: 42. 25 and 53.57 GHz. Thin filter strips saturated with distilled water or an alcohol-water solution were used as absorbing samples of different thicknesses. The dependence of the power reflection coefficient R(d) on film thickness (d) was not monotonic. R(d) passed through a pronounced maximum before reaching its steady-state level [R(infinity)]. Similarly, absorption, A(d), passed two maximums with one minimum between them, before reaching its steady-state level [A(infinity)]. At 42.25 GHz, A(d) was compared with absorption in a semi-infinite water medium at a depth d. When d reflection, transmission, and absorption on d and allowed the determination of the refractive index (n), dielectric constant (epsilon), and penetration depth (delta) of the absorbing medium for various frequencies. For water samples, epsilon was found to be 12.4-19.3j, delta = 0.49 mm at 42.25 GHz, and epsilon = 9.0-19.5j, delta = 0.36 mm at 53.57 GHz. The calculated power density distribution within the film was strongly dependent on d. The measurements and calculations have shown that the reflection and absorption of mm-waves by thin absorbing layers can significantly differ from the reflection and absorption in similar semi-infinite media. The difference in reflection, absorption, and power density distribution in films, as compared to semi-infinite media, are caused by multiple internal reflections from the film boundaries. That is why, when using thin phantoms and thin biological samples, the specifics of the interaction of mm-waves with thin films should be taken into account. Copyright 2000 Wiley-Liss, Inc.

  18. Toward an adjustable nonlinear low frequency acoustic absorber

    Mariani, R.; Bellizzi, S.; Cochelin, B.; Herzog, P.; Mattei, P. O.


    A study of the targeted energy transfer (TET) phenomenon between an acoustic resonator and a thin viscoelastic membrane has recently been presented in the paper [R. Bellet et al., Experimental study of targeted energy transfer from an acoustic system to a nonlinear membrane absorber, Journal of Sound and Vibration 329 (2010) 2768-2791], providing a new path to passive sound control in the low frequency domain where no efficient dissipative device exists. This paper presents experimental results showing that a loudspeaker used as a suspended piston working outside its range of linearity can also be used as a nonlinear acoustic absorber. The main advantage of this technology of absorber is the perspective to adjust independently the device parameters (mass, nonlinear stiffness and damping) according to the operational conditions. To achieve this purpose, quasi-static and dynamic tests have been performed on three types of commercial devices (one with structural modifications), in order to define the constructive characteristics that it should present. An experimental setup has been developed using a one-dimensional acoustic linear system coupled through a box (acting as a weak spring) to a loudspeaker used as a suspended piston acting as an essentially nonlinear oscillator. The tests carried out on the whole vibro-acoustic system have showed the occurrence of the acoustic TET from the acoustic media to the suspended piston and demonstrated the efficiency of this new kind of absorber at low frequencies over a wide frequency range. Moreover, the experimental analyses conducted with different NES masses have confirmed that it is possible to optimize the noise absorption with respect to the excitation level of the acoustic resonator.

  19. Metal Oxide/Zeolite Combination Absorbs H2S

    Voecks, Gerald E.; Sharma, Pramod K.


    Mixed copper and molybdenum oxides supported in pores of zeolite found to remove H2S from mixture of gases rich in hydrogen and steam, at temperatures from 256 to 538 degree C. Absorber of H2S needed to clean up gas streams from fuel processors that incorporate high-temperature steam reformers or hydrodesulfurizing units. Zeolites chosen as supporting materials because of their high porosity, rigidity, alumina content, and variety of both composition and form.

  20. Microwave absorbing properties of activated carbon fibre polymer composites

    Tianchun Zou; Naiqin Zhao; Chunsheng Shi; Jiajun Li


    Microwave absorption of composites containing activated carbon fibres (ACFs) was investigated. The results show that the absorptivity greatly depends on increasing ACF content in the absorbing layer, first increasing and then decreasing. When the content is 0.76 wt.%, the bandwidth below −10dB is 12.2 GHz. Comparing the absorption characteristics of the ACF composite with one containing unactivated fibres, it is found that carbon fibre activation increases the absorption of the composite.

  1. Ruggedizing Printed Circuit Boards Using a Wideband Dynamic Absorber

    V.C. Ho


    Full Text Available The existing approaches to ruggedizing inherently fragile and sensitive critical components of electronic equipment such as printed circuit boards (PCB for use in hostile industrial and military environment are either insufficient or expensive. This paper addresses a novel approach towards ruggedizing commercial-off-the-shelf PCBs using a miniature wideband dynamic absorber. The optimisation technique used relies on the experimentally measured vibration spectra and complex receptance of the original PCB.

  2. Absorbed Doses to Patients in Nuclear Medicine; Doskatalogen foer nukleaermedicin

    Leide-Svegborn, Sigrid; Mattsson, Soeren; Nosslin, Bertil [Universitetssjukhuset MAS, Malmoe (Sweden). Avd. foer radiofysik; Johansson, Lennart [Norrlands Universitetssjukhus, Umeaa (Sweden). Avd. foer radiofysik


    The work with a Swedish catalogue of radiation absorbed doses to patients undergoing nuclear medicine investigations has continued. After the previous report in 1999, biokinetic data and dose estimates (mean absorbed dose to various organs and tissues and effective dose) have been produced for a number of substances: {sup 11}C- acetate, {sup 11}C- methionine, {sup 18}F-DOPA, whole antibody labelled with either {sup 99m}Tc, {sup 111}In, {sup 123}I or {sup 131}I, fragment of antibody, F(ab'){sub 2} labelled with either {sup 99m}Tc, {sup 111}In, {sup 123}I or {sup 131}I and fragment of antibody, Fab' labelled with either {sup 99m}Tc, {sup 111}In, {sup 123}I or {sup 131}I. The absorbed dose estimates for these substances have been made from published biokinetic information. For other substances of interest, e.g. {sup 14}C-urea (children age 3-6 years), {sup 14}C-glycocholic acid, {sup 14}C-xylose and {sup 14}C-triolein, sufficient literature data have not been available. Therefore, a large number of measurements on patients and volunteers have been carried out, in order to determine the biokinetics and dosimetry for these substances. Samples of breast milk from 50 mothers, who had been subject to nuclear medicine investigations, have been collected at various times after administration of the radiopharmaceutical to the mother. The activity concentration in the breast milk samples has been measured. The absorbed dose to various organs and tissues and the effective dose to the child who ingests the milk have been determined for 17 different radiopharmaceuticals. Based on these results revised recommendations for interruption of breast-feeding after nuclear medicine investigations are suggested.

  3. Parametric design of an electrorheological shock absorber with the mixed-mode

    ZHENG Ling; DENG Zhaoxiang; LI Yinong


    A mathematical model based on an electrorheological (ER) shock absorber with the mixed-mode is presented. Its application to the parametric design of an electrorheological fluid shock absorber with the simulation calculation performed by program MATLAB demonstrates that the model can predict the behavior of ER shock absorbers satisfactorily, shorten the design period of an electrorheological shock absorber, and reduce the cost in the prototype manufacturing. The strength analysis based on a three-dimensional finite element model for the electrorheological shock absorber confirm that the structure design of the ER shock absorber is reasonable, and the stress distribution is uniform.

  4. Design and realization of a magnetic-type absorber with a broadened operating frequency band

    Zhou Yong-Jiang; Pang Yong-Qiang; Cheng Hai-Feng


    In this paper,we present an efficient method to obtain absorbers with broadened operating frequency bands.They are accomplished by using conventional magnetic absorbing materials (MAMs) in the forms of array and mesh structures,which are similar to those in the case of a frequency selective surface.The proposed approach is verified not only by simulations but also by experimental results under the normal incidence at microwave frequencies.Moreover,the wideband absorber is lighter than the conventional magnetic absorber.These results indicate that our proposed absorbing structures can be used for designing good electromagnetic absorbers.

  5. Properties of InGaAs quantum dot saturable absorbers in monolithic mode-locked lasers

    Thompson, M.G.; Marinelli, C.; Chu, Y.

    Saturable absorbers properties are characterised in monolithic mode-locked InGaAs quantum dot lasers. We analyse the impact of weak quantum confined Stark effect, fast absorber recovery time and low absorber saturation power on the mode-locking performance.......Saturable absorbers properties are characterised in monolithic mode-locked InGaAs quantum dot lasers. We analyse the impact of weak quantum confined Stark effect, fast absorber recovery time and low absorber saturation power on the mode-locking performance....

  6. Fast ionized X-ray absorbers in AGNs

    Fukumura, K.; Tombesi, F.; Kazanas, D.; Shrader, C.; Behar, E.; Contopoulos, I.


    We investigate the physics of the X-ray ionized absorbers often identified as warm absorbers (WAs) and ultra-fast outflows (UFOs) in Seyfert AGNs from spectroscopic studies in the context of magnetically-driven accretion-disk wind scenario. Launched and accelerated by the action of a global magnetic field anchored to an underlying accretion disk around a black hole, outflowing plasma is irradiated and ionized by an AGN radiation field characterized by its spectral energy density (SED). By numerically solving the Grad-Shafranov equation in the magnetohydrodynamic (MHD) framework, the physical property of the magnetized disk-wind is determined by a wind parameter set, which is then incorporated into radiative transfer calculations with xstar photoionization code under heating-cooling equilibrium state to compute the absorber's properties such as column density N_H, line-of-sight (LoS) velocity v, ionization parameter ξ, among others. Assuming that the wind density scales as n ∝ r-1, we calculate theoretical absorption measure distribution (AMD) for various ions seen in AGNs as well as line spectra especially for the Fe Kα absorption feature by focusing on a bright quasar PG 1211+143 as a case study and show the model's plausibility. In this note we demonstrate that the proposed MHD-driven disk-wind scenario is not only consistent with the observed X-ray data, but also help better constrain the underlying nature of the AGN environment in a close proximity to a central engine.

  7. The Metallicity - Kinematics Relation in Large-N(HI) Absorbers

    Turnshek, D A; Nestor, D B; Belfort-Mihalyi, M; Quider, A; Turnshek, David A.; Rao, Sandhya M.; Nestor, Daniel B.; Belfort-Mihalyi, Michele; Quider, Anna


    Sloan Digital Sky Survey (SDSS) quasar spectroscopy is yielding a database of strong low-ionization MgII absorbers over the redshift interval 0.36absorbers with rest equivalent widths $W^{\\lambda2796}_0 \\ge 0.6$ \\AA have a mean neutral hydrogen column density that is roughly constant at $N(HI) \\approx 4 \\times 10^{20}$ atoms cm$^{-2}$, with individual systems lying in the damped Ly-alpha (DLA) and sub-DLA regimes. Since the MgII doublets generally exhibit saturation, the $W^{\\lambda2796}_0$ values are an indication of the absorbers' velocity spreads. Thus, we can study neutral-gas-phase metallicities as a function of kinematics by forming SDSS composite spectra and measuring weak unsaturated metal lines that form in neutral gas (e.g., CrII, FeII, MnII, SiII, ZnII) as a func...

  8. Wireless device for activation of an underground shock wave absorber

    Chikhradze, M.; Akhvlediani, I.; Bochorishvili, N.; Mataradze, E.


    The paper describes the mechanism and design of the wireless device for activation of energy absorber for localization of blast energy in underground openings. The statistics shows that the greatest share of accidents with fatal results associate with explosions in coal mines due to aero-methane and/or air-coal media explosion. The other significant problem is terrorist or accidental explosions in underground structures. At present there are different protective systems to reduce the blast energy. One of the main parts of protective Systems is blast Identification and Registration Module. The works conducted at G. Tsulukidze Mining Institute of Georgia enabled to construct the wireless system of explosion detection and mitigation of shock waves. The system is based on the constant control on overpressure. The experimental research continues to fulfill the system based on both threats, on the constant control on overpressure and flame parameters, especially in underground structures and coal mines. Reaching the threshold value of any of those parameters, the system immediately starts the activation. The absorber contains a pyrotechnic device ensuring the discharge of dispersed water. The operational parameters of wireless device and activation mechanisms of pyrotechnic element of shock wave absorber are discussed in the paper.

  9. Integration of a neutral absorber for the LHC point 8

    Santamaria, A; Alemany, R; Burkhardt, H; Cerutti, F


    The LHCb detector will be upgraded during the second long shutdown (LS2) of the LHC machine, in order to increase its statistical precision significantly. The upgraded LHCb foresees a peak luminosity of LHL = 1-21033cm-2s-11, with a pileup of ~5. This represents ten times more luminosity and five times more pile up than in the present LHC. With these conditions, the pp-collisions and beam losses will produce a non-negligeable beam-induced energy deposition in the interaction region. More precisely, studies [1] have shown that the energy deposition will especially increase on the D2 recombination dipole, which could bring them close to their safety thresholds. To avoid this, the placement of a minimal neutral absorber has been proposed. This absorber will have the same role as the TAN in the high luminosity Interaction Regions (IR) 1 and 5. This study shows the possible dimensions and location of this absorber, and how it would reduce both the peak power density and total heat load.

  10. Pneumatic Adaptive Absorber: Mathematical Modelling with Experimental Verification

    Grzegorz Mikułowski


    Full Text Available Many of mechanical energy absorbers utilized in engineering structures are hydraulic dampers, since they are simple and highly efficient and have favourable volume to load capacity ratio. However, there exist fields of applications where a threat of toxic contamination with the hydraulic fluid contents must be avoided, for example, food or pharmacy industries. A solution here can be a Pneumatic Adaptive Absorber (PAA, which is characterized by a high dissipation efficiency and an inactive medium. In order to properly analyse the characteristics of a PAA, an adequate mathematical model is required. This paper proposes a concept for mathematical modelling of a PAA with experimental verification. The PAA is considered as a piston-cylinder device with a controllable valve incorporated inside the piston. The objective of this paper is to describe a thermodynamic model of a double chamber cylinder with gas migration between the inner volumes of the device. The specific situation considered here is that the process cannot be defined as polytropic, characterized by constant in time thermodynamic coefficients. Instead, the coefficients of the proposed model are updated during the analysis. The results of the experimental research reveal that the proposed mathematical model is able to accurately reflect the physical behaviour of the fabricated demonstrator of the shock absorber.

  11. Application of Absorbable Hemostatic Materials Observed in Thyroid Operation

    Li, Yan-Ming; Liang, Zhen-Zhen; Song, Yan


    To observe the application effects of the absorbable hemostatic materials in thyroid operation. Methods: From May 2014 to January 2015, 100 patients with thyroid surgery in our university affiliated hospital were selected as the research object. Randomly divided into experimental group and control group, 50 cases in each group. Application of absorbable hemostatic hemostatic materials in the experimental group during the operation, the control group using the traditional mechanical methods of hemostasis hemostasis to observe the operation time, bleeding volume, postoperative drainage volume, complications and hospital stay of the two groups. Results: The operation time, bleeding volume, postoperative drainage and hospital stay in the experimental group were significantly lower in the study group than in the control group, and the difference between the two groups was statistically significant (P 0.05). Conclusion: Absorbable hemostatic materials can effectively shorten the operation time, reduce intraoperative blood loss and postoperative drainage, reduce the length of hospital stay and improve the success rate of surgery and patient satisfaction, which is worthy to be popularized in clinical thyroid surgery.

  12. Graphene metamaterial for multiband and broadband terahertz absorber

    Gao, Runmei; Xu, Zongcheng; Ding, Chunfeng; Wu, Liang; Yao, Jianquan


    In this paper, we present the efficient design of functional graphene thin film metamaterial on a metal-plane separated by a thick dielectric layer. Perfect absorption is characterized by the complete suppression of incident and reflected light and complete dissipation of incident energy. We investigate the properties of graphene metamaterials and demonstrate multiband absorbers that have five absorption bands, using silicon interlayers, in the 0-2.2 THz range. The absorption rate reached up to 99.9% at a frequency of 1.08 THz, and the quality factor was 6.98 for a 0.14 THz bandwidth. We present a novel theoretical interpretation based on standing wave field theory, which shows that coherent superposition of the incident and reflection rays produce stationary waves, and the field energy localized inside the thick spacers and dissipated through the metal-planes. Thus, light was effectively trapped in the metamaterial absorbers with negligible near-field interactions, causing high absorption. The theory developed here explains all features observed in multiband metamaterial absorbers and therefore provides a profound understanding of the underlying physical mechanisms.

  13. Energy scavenging strain absorber: application to kinetic dielectric elastomer generator

    Jean-Mistral, C.; Beaune, M.; Vu-Cong, T.; Sylvestre, A.


    Dielectric elastomer generators (DEGs) are light, compliant, silent energy scavengers. They can easily be incorporated into clothing where they could scavenge energy from the human kinetic movements for biomedical applications. Nevertheless, scavengers based on dielectric elastomers are soft electrostatic generators requiring a high voltage source to polarize them and high external strain, which constitutes the two major disadvantages of these transducers. We propose here a complete structure made up of a strain absorber, a DEG and a simple electronic power circuit. This new structure looks like a patch, can be attached on human's wear and located on the chest, knee, elbow… Our original strain absorber, inspired from a sailing boat winch, is able to heighten the external available strain with a minimal factor of 2. The DEG is made of silicone Danfoss Polypower and it has a total area of 6cm per 2.5cm sustaining a maximal strain of 50% at 1Hz. A complete electromechanical analytical model was developed for the DEG associated to this strain absorber. With a poling voltage of 800V, a scavenged energy of 0.57mJ per cycle is achieved with our complete structure. The performance of the DEG can further be improved by enhancing the imposed strain, by designing a stack structure, by using a dielectric elastomer with high dielectric permittivity.

  14. Fast microwave assisted pyrolysis of biomass using microwave absorbent.

    Borges, Fernanda Cabral; Du, Zhenyi; Xie, Qinglong; Trierweiler, Jorge Otávio; Cheng, Yanling; Wan, Yiqin; Liu, Yuhuan; Zhu, Rongbi; Lin, Xiangyang; Chen, Paul; Ruan, Roger


    A novel concept of fast microwave assisted pyrolysis (fMAP) in the presence of microwave absorbents was presented and examined. Wood sawdust and corn stover were pyrolyzed by means of microwave heating and silicon carbide (SiC) as microwave absorbent. The bio-oil was characterized, and the effects of temperature, feedstock loading, particle sizes, and vacuum degree were analyzed. For wood sawdust, a temperature of 480°C, 50 grit SiC, with 2g/min of biomass feeding, were the optimal conditions, with a maximum bio-oil yield of 65 wt.%. For corn stover, temperatures ranging from 490°C to 560°C, biomass particle sizes from 0.9mm to 1.9mm, and vacuum degree lower than 100mmHg obtained a maximum bio-oil yield of 64 wt.%. This study shows that the use of microwave absorbents for fMAP is feasible and a promising technology to improve the practical values and commercial application outlook of microwave based pyrolysis.

  15. Metamaterial absorbers realized in an X-band rectangular waveguide

    Huang Yong-Jun; Wen Guang-Jun; Li Jian; Zhong Jing-Ping; Wang Ping; Sun Yuan-Hua; O.Gordon; Zhu Wei-Ren


    In this paper,we demonstrate six types of metamaterial absorbers (MMAs) by measuring their absorptivities in an X-band (8-12 GHz) rectangular waveguide.Some of the MMAs have been demonstrated previously by using the free space measurement method,and the others are proposed firstly in this paper.The measured results show that all of the six MMAs exhibit high absorptivities above 98%,which have similar absorbing characteristics to those measured in the free space.The numerically obtained surface current densities for each MMA show that the absorbing mechanism is the same as that under the free space conditions.Such a demonstration method is superior to the conventional free space measurement method due to the small-scale test samples required,the simple measure device,and its low cost.Most importantly,the proposed method opens a way to enable MMAs to be used in microwave applications such as matched terminations.

  16. Sound absorption characteristics of microperforated absorbers for random incidence

    MAA Dah-You; LIU Ke


    Based on previous work on "Statistical absorption coefficient of microperforated absorbers", in which it was shown that theoretical results agree well with experiments on the absorption characteristics of microperforated absorbers (MPA) for random incidence. Further work was carried out in this investigation of the statistical absorption coefficients of MPA in random fields by computation, in order to find the best structure of MPA. It is established that ordinarily the absorption curves of MPA for random incidence and that for normal incidence are quite alike, only that the absorption coefficients are more or less reduced and the whole curve is shifted to higher frequencies without any change of shape. But when the perforate constant k = d/ωρο/4η where d is the diameters of perforations in mm and fo, the absorbers resonance frequency is reduced below 2, say, secondary absorption bands start to play more important role. Pretty soon, they merge with the main absorption band and form a long tail of the latter,extending the absorption far into high frequencies, raising the resulting absorption band to three, four or more octaves. The behavior of the secondary absorption bands is discussed.

  17. Design of Hybrid Dynamic Balancer and Vibration Absorber

    Y. R. Wang


    Full Text Available This study proposed a novel hybrid dynamic balancer and vibration absorber that is cheaper than active dampers and more effective than passive dampers. The proposed damping system does not need to be altered structurally to deal with different damping targets. Rather, the proposed vibration absorber is capable of self-adjustment to the optimal damping location in order to achieve balance and, thereby, optimize damping effects. The proposed device includes a groove under the damping target with inertial mass hung from a coil spring beneath. This allows the device to bounce vertically or rotate in order to reduce vibrations in the main body. The coil spring vibration absorber can also slide along the groove in order to adjust its location continuously until the vibrations in the system are minimized and the main body is balanced. Experiments verify the efficacy of the proposed device in improving damping performance beyond what has been achieved using conventional devices. We also provide an explanation of the theoretical underpinnings of the design as well as the implications of these findings with regard to future developments.

  18. Nonlinear dynamic modeling and resonance tuning of Galfenol vibration absorbers

    Scheidler, Justin J.; Dapino, Marcelo J.


    This paper investigates the semi-active control of a magnetically-tunable vibration absorber’s resonance frequency. The vibration absorber that is considered is a metal-matrix composite containing the magnetostrictive material Galfenol (FeGa). A single degree of freedom model for the nonlinear vibration of the absorber is presented. The model is valid under arbitrary stress and magnetic field, and incorporates the variation in Galfenol’s elastic modulus throughout the composite as well as Galfenol’s asymmetric tension-compression behavior. Two boundary conditions—cantilevered and clamped-clamped—are imposed on the composite. The frequency response of the absorber to harmonic base excitation is calculated as a function of the operating conditions to determine the composite’s capacity for resonance tuning. The results show that nearly uniform controllability of the vibration absorber’s resonance frequency is possible below a threshold of the input power amplitude using weak magnetic fields of 0-8 kA m-1. Parametric studies are presented to characterize the effect on resonance tunability of Galfenol volume fraction and Galfenol location within the composite. The applicability of the results to composites of varying geometry and containing different Galfenol materials is discussed.

  19. Reducing Railway Noise with Porous Sound-Absorbing Concrete Slabs

    Caiyou Zhao


    Full Text Available The effect of porous sound-absorbing concrete slabs on railway noise reduction is examined in this paper. First, the acoustical absorption coefficients of porous concrete materials with various aggregate types, gradations, fibre contents, and compaction indexes are measured in the laboratory. The laboratory results show that porous concrete that uses a composite of expanded perlite and slag as aggregate can not only obtain good acoustical absorption properties but also satisfy mechanical requirements. Also, the gradation of the combined aggregate has a significant effect on the acoustic absorption performance of the porous concrete, with an optimal aggregate gradation of 1~3 mm. Furthermore, the fibre content and compaction index affect both the strength and the acoustic absorption property of the porous concrete, with the optimum value of 0.3% and 1.6, respectively. Then, the findings from the laboratory studies are used to make porous sound-absorbing concrete slabs, which are applied in a test section. The measurements indicate that porous sound-absorbing concrete slabs can significantly reduce railway noise at different train speeds and that the amount of the noise reduction changes roughly linearly with speed when the train is traveling at less than 200 km/h. The maximum noise reduction is 4.05 dB at a speed of 200 km/h.

  20. Optical Properties and Aging of Light Absorbing Secondary Organic Aerosol

    Liu, J.; Lin, P.; Laskin, A.; Laskin, J.; Kathmann, S. M.; Wise, M.; Caylor, R.; Imholt, F.; Selimovic, V.; Shilling, J.


    The light-absorbing organic aerosol (OA), commonly referred to as "brown carbon (BrC)", has attracted considerable attention in recent years because of its potential to affect atmospheric radiation balance, especially in the ultraviolet region and thus impact photochemical processes. A growing amount of data has indicated that BrC is prevalent in the atmosphere, which has motivated numerous laboratory and field studies; however, our understanding of the relationship between the chemical composition and optical properties of BrC remains limited. We conducted chamber experiments to investigate the effect of various VOC precursors, NOx concentrations, photolysis time and relative humidity (RH) on the light absorption of selected secondary organic aerosols (SOA). Light absorption of chamber generated SOA samples, especially aromatic SOA, was found to increase with NOx concentration, at moderate RH, and for the shortest photolysis aging times. The highest mass absorption coefficients (MAC) value is observed from toluene SOA products formed under high NOx conditions at moderate RH, in which nitro-aromatics were previously identified as the major light absorbing compounds. BrC light absorption is observed to decrease with photolysis time, correlated with a decline of the organonitrate fraction of SOA. SOA formed from mixtures of aromatics and isoprene absorb less visible and UV light than SOA formed from aromatic precursors alone on a mass basis. The inherent changes in chemical compositions and the relationship with the light absorption will be discussed in detail.

  1. Absorbability of bulk sol-gel bioactive glasses

    Hamadouche, M.; Meunier, A.; Blanchat, C.; Sedel, L. [Paris-7 Univ. (France). Lab. de Recherches Orthopediques; Greenspan, D.C.; Zhong, J.P.; Torre, G.P. la [US Biomaterials Corp., Alachua, FL (United States)


    Melt-derived bioactive glasses have been used with success in various clinical applications for over 10 years. Recently, particles of sol-gel derived bioactive glasses with an initial high specific area have exhibited high osteoconductive properties, but also a significant degradability. In this work, we explored the in-vivo bioactivity and degradability of bulk sol-gel derived glasses. Two sol-gel compositions (58S and 77S Bioglass) were used. Bulk 45S5 were used as a control. Both sol-gel derived demonstrated similar osteoconductive properties to 45S% Bioglass. In addition, absorbability was observed for sol-gel derived glasses after 12 weeks of implantation. Total absorption reached 40% after 52 weeks. No degradation could be measured in the case of 45S5 melt derived Bioglass. The degradation process was highly time dependent as demonstrated by regression analysis. New bone formation was found to fill in areas that had been resorbed similar to bone remodeling. New bone was found to fill in areas that had been absorbed, similar to natural bone remodeling. This absorbability can be assumed to be at least partially related to an osteoclastic resorption, as viable osteoclasts-like cells were found directly in contact with the glass surfaces. (orig.)

  2. High-Capacity Spacesuit Evaporator Absorber Radiator (SEAR)

    Izenson, Michael G.; Chen, Weibo; Phillips, Scott; Chepko, Ariane; Bue, Grant; Quinn, Gregory


    Future human space exploration missions will require advanced life support technology that can operate across a wide range of applications and environments. Thermal control systems for space suits and spacecraft will need to meet critical requirements for water conservation and multifunctional operation. This paper describes a Space Evaporator Absorber Radiator (SEAR) that has been designed to meet performance requirements for future life support systems. A SEAR system comprises a lithium chloride absorber radiator (LCAR) for heat rejection coupled with a space water membrane evaporator (SWME) for heat acquisition. SEAR systems provide heat pumping to minimize radiator size, thermal storage to accommodate variable environmental conditions, and water absorption to minimize use of expendables. We have built and tested a flight-like, high-capacity LCAR, demonstrated its performance in thermal vacuum tests, and explored the feasibility of an ISS demonstration test of a SEAR system. The new LCAR design provides the same cooling capability as prior LCAR prototypes while enabling over 30% more heat absorbing capacity. Studies show that it should be feasible to demonstrate SEAR operation in flight by coupling with an existing EMU on the space station.

  3. A novel duct silencer using dielectric elastomer absorbers

    Lu, Zhenbo; Cui, Yongdong; Zhu, Jian; Debiasi, Marco


    A novel duct silencer was developed using dielectric elastomer absorbers (DEAs). Dielectric elastomer, a lightweight, high elastic energy density and large deformation under high DC/AC voltages smart material, was used to fabricate this new generation actuator. The acoustic performances of this duct silencer were experimentally investigated in a transmission loss (TL) measurement system using two-load method. It was found that the resonance peaks of this new duct silencer could be controlled by applying various DC voltages, a maximum resonance shift of 59.5Hz for the resonance peaks was achieved which indicated that this duct silencer could be adjusted to absorb broadband range noise without any addition mechanical part. Furthermore, the resonance shift and multiple resonances mechanisms using DEAs were proposed and discussed in the present paper which was aiming to achieve broadband noise reduction. The present results also provide insight into the appropriateness of the absorber for possible use as new acoustic treatment to replace the traditional acoustic treatment.

  4. Dose evaluation of therapeutic radiolabeled bleomycin complexes based on biodistribution data in wild-type rats:Effect of radionuclides in absorbed dose of different organs

    Hassan Yousefnia; Samaneh Zolghadri; Amir Reza Jalilian; Mohammad Ghannadi-Maragheh


    Bleomycins (BLMs), as tumor-seeking antibiotics, have been used for over 20 years in treatment of several types of cancers. Several radioisotopes are used in radiolabeling of BLMs for therapeutic and diagnostic purpos-es. An important points in developing new radiopharmaceuticals, especially therapeutic agents, is the absorbed dose delivered in critical organs. In this work, absorbed dose to organs after injection of 153Sm-, 177Lu-and 166Ho-labeled BLM was investigated by radiation dose assessment resource (RADAR) method based on biodis-tribution data in wild-type rats. The absorbed dose effect of the radionuclides was evaluated. The maximum absorbed dose for the complexes was observed in the kidneys, liver and lungs. For all the radiolabeled BLMs, bone and red marrow received considerable absorbed dose. Due to the high energy beta particles emitted by 166Ho, higher absorbed dose is observed for 166Ho-BLM in the most organs. The reported data can be useful for the determination of the maximum permissible injected activity of the radiolabeled BLMs in the treatment planning programs.

  5. Black carbon or brown carbon? The nature of light-absorbing carbonaceous aerosols

    M. O. Andreae


    Full Text Available Although the definition and measurement techniques for atmospheric 'black carbon' ('BC' or 'elemental carbon'' ('EC' have long been subjects of scientific controversy, the recent discovery of light-absorbing carbon that is not black ('brown carbon, Cbrown' makes it imperative to reassess and redefine the components that make up light-absorbing carbonaceous matter (LAC in the atmosphere. Evidence for the atmospheric presence of Cbrown comes from (1 spectral aerosol light absorption measurements near specific combustion sources, (2 observations of spectral properties of water extracts of continental aerosol, (3 laboratory studies indicating the formation of light-absorbing organic matter in the atmosphere, and (4 indirectly from the chemical analogy of aerosol species to colored natural humic substances. We show that brown carbon may severely bias measurements of 'BC' and 'EC' over vast parts of the troposphere, especially those strongly polluted by biomass burning, where the mass concentration of Cbrown is high relative to that of soot carbon. Chemical measurements to determine 'EC' are biased by the refractory nature of Cbrown as well as by complex matrix interferences. Optical measurements of 'BC' suffer from a number of problems: (1 many of the presently used instruments introduce a substantial bias into the determination of aerosol light absorption, (2 there is no unique conversion factor between light absorption and 'EC' or 'BC' concentration in ambient aerosols, and (3 the difference in spectral properties between the different types of LAC, as well as the chemical complexity of Cbrown, lead to several conceptual as well as practical complications. We also suggest that due to the sharply increasing absorption of Cbrown towards the UV, single-wavelength light absorption measurements may not be adequate for the assessment of absorption of solar radiation in the troposphere. We discuss the possible consequences of these effects for our

  6. Effects Influencing Plutonium-Absorber Interactions and Distributions in Routine and Upset Waste Treatment Plant Operations

    Delegard, Calvin H. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Sinkov, Sergey I. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Fiskum, Sandra K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)


    This report is the third in a series of analyses written in support of a plan to revise the Hanford Waste Treatment and Immobilization Plant (WTP) Preliminary Criticality Safety Evaluation Report (CSER) that is being implemented at the request of the U.S. Department of Energy (DOE) Criticality Safety Group. A report on the chemical disposition of plutonium in Hanford tank wastes was prepared as Phase 1 of this plan (Delegard and Jones 2015). Phase 2 is the provision of a chemistry report to describe the potential impacts on criticality safety of waste processing operations within the WTP (Freer 2014). In accordance with the request from the Environmental and Nuclear Safety Department of the WTP (Miles and Losey 2012), the Phase 2 report assessed the potential for WTP process conditions within and outside the range of normal control parameters to change the ratio of fissile material to neutron-absorbing material in the waste as it is processed with an eye towards potential implications for criticality safety. The Phase 2 study also considered the implications should WTP processes take place within the credible range of chemistry upset conditions. In the present Phase 3 report, the 28 phenomena described in the Phase 2 report were considered with respect to the disposition of plutonium and various absorber elements. The phenomena identified in the Phase 2 report are evaluated in light of the Phase 1 report and other resources to determine the impacts these phenomena might have to alter the plutonium/absorber dispositions and ratios. The outcomes of the Phase 3 evaluations then can be used to inform subsequent engineering decisions and provide reasonable paths forward to mitigate or overcome real or potential criticality concern in plant operations.

  7. The thermal instability of the warm absorber in NGC 3783

    Goosmann, R. W.; Holczer, T.; Mouchet, M.; Dumont, A.-M.; Behar, E.; Godet, O.; Gonçalves, A. C.; Kaspi, S.


    Context. The X-ray absorption spectra of active galactic nuclei frequently show evidence of winds with velocities in the order of 103 km s-1 extending up to 104 km s-1 in the case of ultra-fast outflows. At moderate velocities, these winds are often spectroscopically explained by assuming a number of absorbing clouds along the line of sight. In some cases it was shown that the absorbing clouds are in pressure equilibrium with each other. Aims: We assume a photo-ionized medium with a uniform total (gas+radiation) pressure. The irradiation causes the wind to be radiation pressure compressed (RPC). We attempt to reproduce the observed spectral continuum shape, ionic column densities, and X-ray absorption measure distribution (AMD) of the extensively observed warm absorber in the Seyfert galaxy NGC 3783. Methods: We compare the observational characteristics derived from the 900 ks Chandra observation to radiative transfer computations in pressure equilibrium using the radiative transfer code titan. We explore different values of the ionization parameter ξ of the incident flux and adjust the hydrogen-equivalent column density, NH0, of the warm absorber to match the observed soft X-ray continuum. From the resulting models we derive the column densities for a broad range of ionic species of iron and neon and a theoretical AMD that we compare to the observations. Results: We find an extension of the degeneracy between ξ and NH0 for the constant pressure models previously discussed for NGC 3783. Including the ionic column densities of iron and neon in the comparison between observations and data we conclude that a range of ionization parameters between 4000 and 8000 erg cm s-1 is preferred. For the first time, we present theoretical AMDs for a constant pressure wind in NGC 3783 that correctly reproduces the observed level and is in approximate agreement with the observational appearance of an instability region. Conclusions: Using a variety of observational indicators, we

  8. Light Absorbers and Catalysts for Solar to Fuel Conversion

    Kornienko, Nikolay I.

    Increasing fossil fuel consumption and the resulting consequences to the environment has propelled research into means of utilizing alternative, clean energy sources. Solar power is among the most promising of renewable energy sources but must be converted into an energy dense medium such as chemical bonds to render it useful for transport and energy storage. Photoelectrochemistry (PEC), the splitting of water into oxygen and hydrogen fuel or reducing CO 2 to hydrocarbon fuels via sunlight is a promising approach towards this goal. Photoelectrochemical systems are comprised of several components, including light absorbers and catalysts. These parts must all synergistically function in a working device. Therefore, the continual development of each component is crucial for the overall goal. For PEC systems to be practical for large scale use, the must be efficient, stable, and composed of cost effective components. To this end, my work focused on the development of light absorbing and catalyst components of PEC solar to fuel converting systems. In the direction of light absorbers, I focused of utilizing Indium Phosphide (InP) nanowires (NWs) as photocathodes. I first developed synthetic techniques for InP NW solution phase and vapor phase growth. Next, I developed light absorbing photocathodes from my InP NWs towards PEC water splitting cells. I studied cobalt sulfide (CoSx) as an earth abundant catalyst for the reductive hydrogen evolution half reaction. Using in situ spectroscopic techniques, I elucidated the active structure of this catalyst and offered clues to its high activity. In addition to hydrogen evolution catalysts, I established a new generation of earth abundant catalysts for CO2 reduction to CO fuel/chemical feedstock. I first worked with molecularly tunable homogeneous catalysts that exhibited high selectivity for CO2 reduction in non-aqueous media. Next, in order to retain molecular tunability while achieving stability and efficiency in aqueous

  9. Synthesis and absorbing mechanism of two-layer microwave absorbers containing polycrystalline iron fibers and carbonyl iron

    Ding, Qingwei; Zhang, Mingang; Zhang, Cunrui; Qian, Tianwei


    Polycrystalline iron fibers were fabricated by α-FeOOH fiber precursors. Two-layer microwave absorber had been prepared by as-prepared polycrystalline iron fibers and carbonyl iron. The structure, morphology and properties of the composites were characterized with X-ray diffraction, scanning electron microscope and Network Analyzer. The complex permittivity and reflection loss (dB) of the composites were measured employing vector network analyzer model PNA 3629D vector in the frequency range between 30 and 6000 MHz. The thickness effect of the carbonyl iron layer on the microwave loss properties of the composites was investigated. A possible microwave-absorbing mechanism of polycrystalline iron fibers/carbonyl iron composite was proposed. The polycrystalline iron fibers/carbonyl iron composite can find applications in suppression of electromagnetic interference, and reduction of radar signature.




    Full Text Available Introduction: As many as 35 percent of the world population suffer from some degree of iron deficiency anemia. According to recent reports published by WHO and ICN (International Congress of Nutrition 20-40 percent of women are suffering from iron deficiency. Iron deficiency anemia is caused by lack of intake of the necessary doses of Fe+2 called Heme. The recommended intake dose is 10-17 mg Fe + 2/day. In Iran, bread is the main source of daily iron intake. However, the iron content of bread is Fe+3 which is not absorbable. The objectives of this study is to determine the levels of absorbable iron (Fe + 2 in two common types of Iranian bread and identify the means of raising these to an adequate levels.
    Methods: Random sampling method together with the normal distribution curve was employed in testing 120 samples of flour and bread. Quantification was carried out on each sample in duplicate using spectrophotometer at 510 mu, micrometer wave length. The effect of three organic acids (lactic ascorbic and acetic acid converting of Fe+3 to Fe + 2 was investigated. Two groups of bread was tested. One group was baked in tratitional oven (Noon-e-Tanoori and the second group through the common Iranian hot rotating iron plate baking machine (Noon-e-Machini.
    Results: Our results showed that the amount of absorbable Fe+2 in breads baked in rotatory oven (Noon-e-Tanoori is 0.8 ± 0.32 mg and the amount of unabsorbable Fe+3 in dried bread is 2.34 ± 0.25 mg/100 gm while the amount of absorbable Fe + 2 baked in traditional ovens is only 0.3±0.11 mg versus of unabsorbable Fe  + 3 1.9±0.13 mg/100 gm of dried bread. Meanwhile it was found that lactic and ascorbic acids can convert Fe+3 to Fe+2. Therefore, addition of one of these two acids to bread can catalyze conversion of unabsorbable Fe+3 to absorbable Fe + 2.
    Discussion: On the average an Iranian consumes 370 gm of

  11. Effect of thermal-treatment sequence on sound absorbing and mechanical properties of porous sound-absorbing/thermal-insulating composites

    Huang Chen-Hung; Tsay Cherng-Shiuan; Lou Ching-Wen; Chuang Yu-Chun; Shih Ying-Huei; Lin Jia-Horng


    Due to recent rapid commercial and industrial development, mechanical equipment is supplemented massively in the factory and thus mechanical operation causes noise which distresses living at home. In livelihood, neighborhood, transportation equipment, jobsite construction noises impact on quality of life not only factory noise. This study aims to preparation technique and property evaluation of porous sound-absorbing/thermal-insulating composites. Hollow three-dimensional crimp PET fibers ble...

  12. A biomimetic absorbent for removal of trace level persistent organic pollutants from water.

    Liu, Huijuan; Qu, Jiuhui; Dai, Ruihua; Ru, Jia; Wang, Zijian


    A novel biomimetic absorbent containing the lipid triolein was developed for removing persistent organic pollutants (POPs) from water. The structural characteristics of the absorbent were obtained by SEM and a photoluminescence method. Under optimum preparation conditions, triolein was perfectly embedded in the cellulose acetate (CA) spheres, the absorbent was stable and no triolein leaked into the water. Dieldrin, endrin, aldrin and heptachlor epoxide were effectively removed by the CA--triolein absorbent in laboratory batch experiments. This suggests that CA-triolein absorbent may serve as a good absorbent for those selected POPs. Triolein in the absorbent significantly increased the absorption capacity, and lower residual concentrations of POPs were achieved when compared to the use of cellulose acetate absorbent. The absorption rate for lipophilic pollutants was very fast and exhibited some relationship with the octanol--water partition coefficient of the analyte. The absorption mechanism is discussed in detail.

  13. Absorbent properties of carboxymethylated fiber, hydroentangled nonwoven and regenerated cellulose: a comparative study

    Commercially-available, bleached cotton fibers, rayon, and their hydroentangled counterparts were carboxymethylated to produce cellulosic products with increased absorbency. These cellulose materials were tested for absorbance, spectroscopic properties, degree of substitution and carding ability. Ca...

  14. A smart radar absorber based on the phase-switched screen \\ud

    Chambers, B; Tennant, A


    Although conventional (i.e., passive) radar absorbers are widely used for modifying the radar cross-section (RCS) of current military platforms, such absorbers may not have adequate performance to satisfy future requirements. Active absorbers, however, offer the potential to overcome the so-called Rozanov performance limit and to enable additional smart functionality such as monitoring damage, adaptive control of RCS or target appearance, identification-friend-or-foe, and absorb-while-scan. T...

  15. The Dry-filling System for the Shock Absorber of Car Engine

    Du Rong


    Full Text Available The shock absorber is considered as an important component of the suspension system. In its production process, the liquid filling for the shock absorber is a very important part. This paper introduced one kind of shock absorber stem–filling system, which achieved liquid dry-filling in the shock absorber for the car engine. The results showed that this system is stable and reliable.

  16. Self-assembly of highly efficient, broadband plasmonic absorbers for solar steam generation

    Lin ZHOU; Tan, Yingling; Ji, Dengxin; Zhu, Bin; Zhang, Pei; Xu, Jun; Gan, Qiaoqiang; Yu, Zongfu; Zhu, Jia


    The study of ideal absorbers, which can efficiently absorb light over a broad range of wavelengths, is of fundamental importance, as well as critical for many applications from solar steam generation and thermophotovoltaics to light/thermal detectors. As a result of recent advances in plasmonics, plasmonic absorbers have attracted a lot of attention. However, the performance and scalability of these absorbers, predominantly fabricated by the top-down approach, need to be further improved to e...

  17. Pulse Delay and Speed-up of Ultra Fast Pulses in an Absorbing Quantum Well Medium

    Hansen, Per Lunnemann; Poel, Mike van der; Yvind, Kresten;


    Slow down and speed-up of 180 fs pulses in an absorbing semiconductor beyond the exisitng models is observed. Cascading gainand absorbing sections give us significant temporal pulse shifting at almost constant output pulse energy.......Slow down and speed-up of 180 fs pulses in an absorbing semiconductor beyond the exisitng models is observed. Cascading gainand absorbing sections give us significant temporal pulse shifting at almost constant output pulse energy....

  18. A contribution to the investigation of the heat load of shock absorbers of semi-active suspensions in motor vehicles

    Miroslav D. Demić


    the given vehicle model  have been written using the "NEWEUL." software package. The data input has been done in accordance with the program requirements, and 24 coordinate systems (including inertial-OI1I2I3 global coordinate system have been used to define the dynamic vehicle model with seven degrees of freedom. Thermal load on the shock absorbers of the semi-active suspension system Due to the relative motion between sprunged and unsprunged masses, mechanical work in the absorbers is equivalent to the amount of heat Q, J. As the heat flux is of a random size, it was assessed as appropriate to calculate the average power (flux for each buffer separately, and the data are given in Table 1 Table 1 Medium heat flux during a movement of  20, s Medium flux, W Front left absorber Front right absorber Rear left absorber Rear right absorber Speed 30,m/s, Mass 100% 2.330434E-006   5.569178E-006 5.358273E-006 2.944404E-006 Speed  5, m/s Mass 100% 2.435122E-006   5.673833E-006 5.477176E-006 2.968751E-006 Mass 75%, Speed 5, m/s 2.431798E-006   4.518553E-006 4.263119E-006 2.748116E-006 For  illustration, Fig. 1 shows the work converted to heat amount in the  shock absorbers of the semi-active suspension system, for a vehicle speed of  5 m/s. The analysis of the heat amount data for a speed of 5 and 30, m/s,for an illustrative example of a speed of 5, m / s , given in Fig. 1 shows that the amount of heat production increases with the covered distance (time. If the vehicle speed increases, the amount of heat decreases. The example in  Fig. 2 shows the effect of the vehicle load on the heat amount generated in the semi-active suspension system absorbers. Namely, the figure shows mechanical work (converted into heat in the shock absorbers of a partially loaded vehicle (75% while moving at a speed of 5, m / s. It can be determined that the reduced load on a vehicle leads to reduced thermal shock loading of vehicles, which is in accordance with heat flux.ConclusionBased on

  19. The estimation of absorbed dose rates for non-human biota : an extended inter-comparison.

    Batlle, J. V. I.; Beaugelin-Seiller, K.; Beresford, N. A.; Copplestone, D.; Horyna, J.; Hosseini, A.; Johansen, M.; Kamboj, S.; Keum, D.-K.; Kurosawa, N.; Newsome, L.; Olyslaegers, G.; Vandenhove, H.; Ryufuku, S.; Lynch, S. V.; Wood, M. D.; Yu, C. (Environmental Science Division); (Westlakes Scientific Consulting Ltd.); (Inst. de Radioprotection et de Surete Nucleaire); (Centre for Ecology & Hydrology); (Norwegian Radiation Protection Authority); (State Office for Nuclear Safety); (Korea Atomic Energy Research Institute); (Visible Information Centre Inc.); (Belgian Nuclear Research Centre); (University of Liverpool)


    An exercise to compare 10 approaches for the calculation of unweighted whole-body absorbed dose rates was conducted for 74 radionuclides and five of the ICRP's Reference Animals and Plants, or RAPs (duck, frog, flatfish egg, rat and elongated earthworm), selected for this exercise to cover a range of body sizes, dimensions and exposure scenarios. Results were analysed using a non-parametric method requiring no specific hypotheses about the statistical distribution of data. The obtained unweighted absorbed dose rates for internal exposure compare well between the different approaches, with 70% of the results falling within a range of variation of {+-}20%. The variation is greater for external exposure, although 90% of the estimates are within an order of magnitude of one another. There are some discernible patterns where specific models over- or under-predicted. These are explained based on the methodological differences including number of daughter products included in the calculation of dose rate for a parent nuclide; source-target geometry; databases for discrete energy and yield of radionuclides; rounding errors in integration algorithms; and intrinsic differences in calculation methods. For certain radionuclides, these factors combine to generate systematic variations between approaches. Overall, the technique chosen to interpret the data enabled methodological differences in dosimetry calculations to be quantified and compared, allowing the identification of common issues between different approaches and providing greater assurance on the fundamental dose conversion coefficient approaches used in available models for assessing radiological effects to biota.

  20. Development of a Marslander with crushable shock absorber by virtual and experimental testing

    Schröder, Silvio; Reinhardt, B.; Brauner, C.; Gebauer, I.; Buchwald, R.


    Since the beginning of space exploration, probes have been sent to other planets or moons with the associated challenge of landing on these bodies. For a soft landing several damping methods like landing legs or airbags have been used. A new and potentially less complex and lighter way to reduce the shock loads at touchdown is the use of a crushable shield underneath the lander platform. This crushable shield could be made for example out of an energy absorbing materials like an aluminum honeycomb core with a High Performance Polyethylene cover sheet. The design is particularly advantageous since no moving parts nor other mechanisms are required, thus making the shield very robust and fail safe. The only mission that has used this technique is the ESA/Roscosmos-mission ;ExoMars; which started in 2016. The development of such a crushable shock absorber implies and requires assessment of materials, manufacturing processes, the setup of a numerical simulation and the experimental validation in a test lab. In an independent research project (Marslander) a representative engineering mockup of the landing platform has been built and tested at the Landing & Mobility Test Facility (LAMA) to support the numerical simulation model with experimental data. This paper is focusing on the hardware tests. Results of the above stated development and testing processes will be presented and discussed.