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Sample records for cell concentration system

  1. Solar cell concentrating system

    International Nuclear Information System (INIS)

    Garg, H.P.; Sharma, V.K.; Agarwal, R.K.

    1986-11-01

    This study reviews fabrication techniques and testing facilities for different solar cells under concentration which have been developed and tested. It is also aimed to examine solar energy concentrators which are prospective candidates for photovoltaic concentrator systems. This may provide an impetus to the scientists working in the area of solar cell technology

  2. High concentration photovoltaic systems applying III-V cells

    International Nuclear Information System (INIS)

    Zubi, Ghassan; Bernal-Agustin, Jose L.; Fracastoro, Gian Vincenzo

    2009-01-01

    High concentration systems make use of the direct solar beam and therefore are suitable for application in regions with high annual direct irradiation values. III-V PV cells with a nominal efficiency of up to 39% are readily available in today's market, with further efficiency improvements expected in the years ahead. The relatively high cost of III-V cells limits their terrestrial use to applications under high concentration, usually above 400 suns. In this way the relatively high cell cost is compensated through the low amount for cells needed per kW nominal system output. This paper presents a state of the art of high concentration photovoltaics using III-V cells. This PV field accounts already for more than 20 developed systems, which are commercially available or shortly before market introduction. (author)

  3. Point-focus spectral splitting solar concentrator for multiple cells concentrating photovoltaic system

    International Nuclear Information System (INIS)

    Maragliano, Carlo; Chiesa, Matteo; Stefancich, Marco

    2015-01-01

    In this paper we present and experimentally validate a low-cost design of a spectral splitting concentrator for the efficient conversion of solar energy. The optical device consists of a dispersive prismatic lens made of polycarbonate designed to simultaneously concentrate solar light and split it into its spectral components. With respect to our previous implementation, this device concentrates light along two axes and generates a light pattern compatible with the dimensions of a set of concentrating photovoltaic cells, while providing a higher concentration ratio. The mathematical framework and the constructive approach used for the design are presented and the device performance is simulated using ray-tracing software. We obtain spectral separation in the visible range within a 3 × 1 cm 2 area and a maximum concentration of 210× for a single wavelength. The device is fabricated by injection molding and its performance is experimentally investigated. We measure an optical transmissivity above 90% in the range 400–800 nm and we observe a spectral distribution in good accordance with simulations. Our results demonstrate the feasibility of the device for cost effective high efficiency concentrated photovoltaic systems. (paper)

  4. Design and Operation of an Electrochemical Methanol Concentration Sensor for Direct Methanol Fuel Cell Systems

    Science.gov (United States)

    Narayanan, S. R.; Valdez, T. I.; Chun, W.

    2000-01-01

    The development of a 150-Watt packaged power source based on liquid feed direct methanol fuel cells is being pursued currently at the Jet propulsion Laboratory for defense applications. In our studies we find that the concentration of methanol in the fuel circulation loop affects the electrical performance and efficiency the direct methanol fuel cell systems significantly. The practical operation of direct methanol fuel cell systems, therefore, requires accurate monitoring and control of methanol concentration. The present paper reports on the principle and demonstration of an in-house developed electrochemical sensor suitable for direct methanol fuel cell systems.

  5. Increasing Fuel Efficiency of Direct Methanol Fuel Cell Systems with Feedforward Control of the Operating Concentration

    Directory of Open Access Journals (Sweden)

    Youngseung Na

    2015-09-01

    Full Text Available Most of the R&D on fuel cells for portable applications concentrates on increasing efficiencies and energy densities to compete with other energy storage devices, especially batteries. To improve the efficiency of direct methanol fuel cell (DMFC systems, several modifications to system layouts and operating strategies are considered in this paper, rather than modifications to the fuel cell itself. Two modified DMFC systems are presented, one with an additional inline mixer and a further modification of it with a separate tank to recover condensed water. The set point for methanol concentration control in the solution is determined by fuel efficiency and varies with the current and other process variables. Feedforward concentration control enables variable concentration for dynamic loads. Simulation results were validated experimentally with fuel cell systems.

  6. Optimized scalable stack of fluorescent solar concentrator systems with bifacial silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Martínez Díez, Ana Luisa, E-mail: a.martinez@itma.es [Fundación ITMA, Parque Empresarial Principado de Asturias, C/Calafates, Parcela L-3.4, 33417 Avilés (Spain); Fraunhofer Institute for Solar Energy Systems ISE, Heidenhofstr. 2, 79110 Freiburg (Germany); Gutmann, Johannes; Posdziech, Janina; Rist, Tim; Goldschmidt, Jan Christoph [Fraunhofer Institute for Solar Energy Systems ISE, Heidenhofstr. 2, 79110 Freiburg (Germany); Plaza, David Gómez [Fundación ITMA, Parque Empresarial Principado de Asturias, C/Calafates, Parcela L-3.4, 33417 Avilés (Spain)

    2014-10-21

    In this paper, we present a concentrator system based on a stack of fluorescent concentrators (FCs) and a bifacial solar cell. Coupling bifacial solar cells to a stack of FCs increases the performance of the system and preserves its efficiency when scaled. We used an approach to optimize a fluorescent solar concentrator system design based on a stack of multiple fluorescent concentrators (FC). Seven individual fluorescent collectors (20 mm×20 mm×2 mm) were realized by in-situ polymerization and optically characterized in regard to their ability to guide light to the edges. Then, an optimization procedure based on the experimental data of the individual FCs was carried out to determine the stack configuration that maximizes the total number of photons leaving edges. Finally, two fluorescent concentrator systems were realized by attaching bifacial silicon solar cells to the optimized FC stacks: a conventional system, where FC were attached to one side of the solar cell as a reference, and the proposed bifacial configuration. It was found that for the same overall FC area, the bifacial configuration increases the short-circuit current by a factor of 2.2, which is also in agreement with theoretical considerations.

  7. The effects of concentrated system on the electrical parameters of GaInP/GaAs solar cell

    Science.gov (United States)

    Kınacı, Barış

    2017-02-01

    III-V concentrator solar cells are suitable materials in order to reduce the cost of photovoltaic electricity. By using Fresnel lens in concentrating photovoltaic technology is an effective way to entirely use the sunlight. In the present study, the research on the efficiency analysis of the GaInP/GaAs concentrated solar cell structure with AlGaAs tunnel junction was performed. The electrical output parameters of this structure were determined by concentrated system with Fresnel lens. The current-voltage measurements of concentrated solar cell were carried out at room temperature under both dark and air mass 1.5 global radiations. The parameters of GaInP/GaAs concentrated solar cell at 1 Sun and at 32 Suns are compared. It is obtained that the integration of the concentrated system on the solar cell structure improves the device performance by ≈7.5%.

  8. Outdoor performance of a low-concentrated photovoltaic–thermal hybrid system with crystalline silicon solar cells

    International Nuclear Information System (INIS)

    Kong, Chengdong; Xu, Zilin; Yao, Qiang

    2013-01-01

    Highlights: ► Four different weather conditions are considered and characterized. ► The concentrator is carefully designed to get a uniformly concentrated irradiation. ► A model is made to evaluate the system with optical efficiency of concentrators considered. ► Direct and diffuse lights are distinguished in the model. - Abstract: The main problem of the photovoltaic system is the high cost of solar cells. One possible solution is to concentrate the solar radiation to minimize the required cell area for the same output. In this paper a low-concentrating photovoltaic–thermal hybrid (PV/T) system was set up to study the electrical and thermal outputs under different weather conditions. The concentrator in the system was designed using Fresnel lens and flat mirrors to get a uniformly concentrated irradiation on the solar cells. The results show that on a clear day the electrical efficiency is about 10% and the thermal efficiency is about 56% for our system. Irradiance is the most important factor to characterize the weather. When the irradiance is above 350 W/m 2 the electrical output will saturate and when it is above 162 W/m 2 the thermal energy can be effectively output in our system. The system is also modeled to predict the output and describe the concentrator’s performance. By this model different concentrated PV/T systems can be compared in the electrical and thermal outputs and also the performance of concentrators

  9. The effect of the optical system on the electrical performance of III-V concentrator triple junction solar cells

    Science.gov (United States)

    Schultz, R. D.; van Dyk, E. E.; Vorster, F. J.

    2016-01-01

    High Concentrated Photovoltaic (H-CPV) technologies utilize relatively inexpensive reflective and refractive optical components for concentration to achieve high energy yield. The electrical performance of H-CPV systems is, however, dependent on the properties and configuration of the optical components. The focus of this paper is to summarize the effect of the properties of the optical system on the electrical performance of a Concentrator Triple Junction (CTJ) InGaP/InGaAs/Ge cell. Utilizing carefully designed experiments that include spectral measurements and intensity profiles in the optical plane of the CTJ cell, the influence of photon absorption, Fresnel lens properties and chromatic aberration created by the optical system on the electrical performance of a CTJ cell is shown. From the results obtained, it is concluded that good characterization and understanding of the optical system's properties may add to improved design of future multi-junction devices.

  10. The effect of the optical system on the electrical performance of III–V concentrator triple junction solar cells

    International Nuclear Information System (INIS)

    Schultz, R.D.; Dyk, E.E. van; Vorster, F.J.

    2016-01-01

    High Concentrated Photovoltaic (H-CPV) technologies utilize relatively inexpensive reflective and refractive optical components for concentration to achieve high energy yield. The electrical performance of H-CPV systems is, however, dependent on the properties and configuration of the optical components. The focus of this paper is to summarize the effect of the properties of the optical system on the electrical performance of a Concentrator Triple Junction (CTJ) InGaP/InGaAs/Ge cell. Utilizing carefully designed experiments that include spectral measurements and intensity profiles in the optical plane of the CTJ cell, the influence of photon absorption, Fresnel lens properties and chromatic aberration created by the optical system on the electrical performance of a CTJ cell is shown. From the results obtained, it is concluded that good characterization and understanding of the optical system’s properties may add to improved design of future multi-junction devices.

  11. A new procedure for estimating the cell temperature of a high concentrator photovoltaic grid connected system based on atmospheric parameters

    International Nuclear Information System (INIS)

    Fernández, Eduardo F.; Almonacid, Florencia

    2015-01-01

    Highlights: • Concentrating grid-connected systems are working at maximum power point. • The operating cell temperature is inherently lower than at open circuit. • Two novel methods for estimating the cell temperature are proposed. • Both predict the operating cell temperature from atmospheric parameters. • Experimental results show that both methods perform effectively. - Abstract: The working cell temperature of high concentrator photovoltaic systems is a crucial parameter when analysing their performance and reliability. At the same time, due to the special features of this technology, the direct measurement of the cell temperature is very complex and is usually obtained by using different indirect methods. High concentrator photovoltaic modules in a system are operating at maximum power since they are connected to an inverter. So that, their cell temperature is lower than the cell temperature of a module at open-circuit voltage since an important part of the light power density is converted into electricity. In this paper, a procedure for indirectly estimating the cell temperature of a high concentrator photovoltaic system from atmospheric parameters is addressed. Therefore, this new procedure has the advantage that is valid for estimating the cell temperature of a system at any location of interest if the atmospheric parameters are available. To achieve this goal, two different methods are proposed: one based on simple mathematical relationships and another based on artificial intelligent techniques. Results show that both methods predicts the cell temperature of a module connected to an inverter with a low margin of error with a normalised root mean square error lower or equal than 3.3%, an absolute root mean square error lower or equal than 2 °C, a mean absolute error lower or equal then 1.5 °C, and a mean bias error and a mean relative error almost equal to 0%

  12. Experimental study on direct-contact liquid film cooling simulated dense-array solar cells in high concentrating photovoltaic system

    International Nuclear Information System (INIS)

    Wang, Yiping; Shi, Xusheng; Huang, Qunwu; Cui, Yong; Kang, Xue

    2017-01-01

    Highlights: • Direct-contact liquid film cooling dense-array solar cells was first proposed. • Average temperature was controlled well below 80 °C. • The maximum temperature difference was less than 10 °C. • The heat transfer coefficient reached up to 11.91 kW/(m 2 ·K) under 589X. - Abstract: This paper presented a new method of cooling dense-array solar cells in high concentrating photovoltaic system by direct-contact liquid film, and water was used as working fluid. An electric heating plate was designed to simulate the dense-array solar cells in high concentrating photovoltaic system. The input power of electric heating plate simulated the concentration ratios. By heat transfer experiments, the effect of water temperatures and flow rates on heat transfer performance was investigated. The results indicated that: the average temperature of simulated solar cells was controlled well below 80 °C under water temperature of 30 °C and flow rate of 300 L/h when concentration ratio ranged between 300X and 600X. The maximum temperature difference among temperature measurement points was less than 10 °C, which showed the temperature distribution was well uniform. The heat transfer coefficient reached up to 11.91 kW/(m 2 ·K) under concentration ratio of 589X. To improve heat transfer performance and obtain low average temperature of dense-array solar cells, lower water temperature and suitable water flow rate are preferred.

  13. NGCPV: A new generation of concentrator photovoltaic cells, modules and systems

    OpenAIRE

    Cristóbal López, Ana Belén; Martí Vega, Antonio; Sala Pano, Gabriel; Bett, Andreas W.; Ekins-Daukes, Ned; Roca, Franco; Luque Heredia, Ignacio; Warmuth, Werner; Merten, Jens; Okada, Y.; Hishikawa, Y.; Takamoto, Tatsuya; Araki, Kenji; Fukuyama, A.; Kuze, N.

    2012-01-01

    This work introduces the lines of research that the NGCPV project is pursuing and some of the first results obtained. Sponsored by the European Commission under the 7th Framework Program and NEDO (Japan) within the first collaborative call launched by both Bodies in the field of energy, NGCPV project aims at approaching the cost of the photovoltaic kWh to competitive prices in the framework of high concentration photovoltaics (CPV) by exploring the development and assessment of concentrator p...

  14. Concentrator cell status and projections

    Energy Technology Data Exchange (ETDEWEB)

    Arvizu, D.E.

    1984-08-01

    Over the last few years much work has been directed at improving conventional single crystal silicon cells for concentrator application. Although 20% efficient concentrator cells have been fabricated, the current thinking indicates that conventional silicon devices are approaching theoretical maximums. The primary emphasis of today's Federal program for concentrating photovoltaics is directed at advanced high efficiency devices. Advanced device approaches that are being pursued include patterned diffusion silicon designs with practical efficiency limits greater than 25%, optimized conventional GaAs devices with efficiency limits near 28%, and multiple-junction structures with efficiency limits over 35%. Progress in each of these areas are reviewed.

  15. Concentrator-solar-cell development

    Science.gov (United States)

    Grenon, L.

    1982-07-01

    A program is described which is a continuation of earlier programs for the development of high-efficiency, low-cost, silicon concentrator solar cells. The base-line process steps and process sequences identified in these earlier contracts were evaluated and specific processes reviewed. In particular, emphasis on the use of Czochralski-grown silicon wafers rather than float-zone wafers were examined. Additionally, a study of the trade-offs between textured and nontextured cells was initiated, and the limits within which the low-cost plated nickel copper metallization can be used in concentrator solar cell applications was identified.

  16. Dual temperature concentration system

    International Nuclear Information System (INIS)

    Spevack, J.S.

    1975-01-01

    In a dual temperature isotope exchange system--exemplified by exchange of deuterium and protium between water and hydrogen sulfide gas in hot and cold towers, in which the feed stream (water) containing the desired isotope is passed through a pair of towers maintained at different temperatures wherein it effects isotope exchange with countercurrently circulated auxiliary fluid (H 2 S) and is impoverished in said isotope and then disposed of, e.g. discharged to waste,--the flow of isotope enriched auxiliary fluid between said towers (hot H 2 S saturated with water vapor) is divided and a part thereof is adjusted in its temperature (to cold tower conditions) and then passed to the auxiliary fluid impoverishing (cold) tower, while the remainder of the divided flow of such enriched auxiliary fluid is passed through a subsequent isotope concentration treatment to produce a product more highly enriched in the desired isotope and wherein it is also adjusted in its temperature and is impoverished in said isotope during said subsequent treatment before it is delivered to the said auxiliary fluid impoverishing (cold) tower. Certain provisions are made for returning to the hot tower liquid carried as vapor by the remainder of the divided flow to the subsequent isotope concentration treatment, for recovering sensible and latent heat, and for reducing passage of auxiliary fluid to waste

  17. Advanced high efficiency concentrator cells

    Energy Technology Data Exchange (ETDEWEB)

    Gale, R. (Varian Associates, Inc., Palo Alto, CA (United States). Varian Research Center)

    1992-06-01

    This report describes research to develop the technology needed to demonstrate a monolithic, multijunction, two-terminal, concentrator solar cell with a terrestrial power conversion efficiency greater than 35%. Under three previous subcontracts, Varian developed many of the aspects of a technology needed to fabricate very high efficiency concentrator cells. The current project was aimed at exploiting the new understanding of high efficiency solar cells. Key results covered in this report are as follows. (1) A 1.93-eV AlGaAs/1.42-eV GaAs metal-interconnected cascade cell was manufactured with a one-sun efficiency at 27.6% at air mass 1.5 (AM1.5) global. (2) A 1.0eV InGaAs cell was fabricated on the reverse'' side of a low-doped GaAs substrate with a one-sun efficiency of 2.5% AM1.5 diffuse and a short-circuit current of 14.4 mA/cm{sup 2}. (3) Small-scale manufacturing of GaAs p/n concentrator cells was attempted and obtained an excellent yield of high-efficiency cells. (4) Grown-in tunnel junction cell interconnects that are transparent and thermally stable using C and Si dopants were developed. 10 refs.

  18. Soft lithography for concentrator photovoltaic CPV - system's ...

    African Journals Online (AJOL)

    Soft lithography for concentrator photovoltaic CPV - system's application. ... Soft lithography for concentrator photovoltaic CPV - system's application. N.L. Chiromawa, K Ibrahim, M.H. Ali, U.M. Gana, A.O. Musa, N.I. Mannawi, A.A. ... Abstract. No Abstract. Keywords: Micro-Fresnel lens,Photovoltaic, Solar cells, PMMA, PDMS ...

  19. Optimal concentrations in transport systems

    Science.gov (United States)

    Jensen, Kaare H.; Kim, Wonjung; Holbrook, N. Michele; Bush, John W. M.

    2013-01-01

    Many biological and man-made systems rely on transport systems for the distribution of material, for example matter and energy. Material transfer in these systems is determined by the flow rate and the concentration of material. While the most concentrated solutions offer the greatest potential in terms of material transfer, impedance typically increases with concentration, thus making them the most difficult to transport. We develop a general framework for describing systems for which impedance increases with concentration, and consider material flow in four different natural systems: blood flow in vertebrates, sugar transport in vascular plants and two modes of nectar drinking in birds and insects. The model provides a simple method for determining the optimum concentration copt in these systems. The model further suggests that the impedance at the optimum concentration μopt may be expressed in terms of the impedance of the pure (c = 0) carrier medium μ0 as μopt∼2αμ0, where the power α is prescribed by the specific flow constraints, for example constant pressure for blood flow (α = 1) or constant work rate for certain nectar-drinking insects (α = 6). Comparing the model predictions with experimental data from more than 100 animal and plant species, we find that the simple model rationalizes the observed concentrations and impedances. The model provides a universal framework for studying flows impeded by concentration, and yields insight into optimization in engineered systems, such as traffic flow. PMID:23594815

  20. Outdoor performance analysis of a 1090× point-focus Fresnel high concentrator photovoltaic/thermal system with triple-junction solar cells

    International Nuclear Information System (INIS)

    Xu, Ning; Ji, Jie; Sun, Wei; Han, Lisheng; Chen, Haifei; Jin, Zhuling

    2015-01-01

    Graphical abstract: A high concentrator photovoltaic/thermal (HCPV/T) system based on point-focus Fresnel lens has been set up in this work. The concentrator has a geometric concentration ratio of 1090× and uniform irradiation distribution can be obtained on solar cells. The system produces both electricity and heat. Performance of the system has been investigated based on the outdoor measurement in a clear day. The HCPV/T system presents an instantaneous electrical efficiency of 28% and a highest instantaneous thermal efficiency of 54%, respectively. Experimental results show that direct irradiation affects the electrical performance of the system dominantly. Fitting results of electrical performance offer simple and reliable methods to analyze the system performance. - Highlights: • A point-focus Fresnel lens photovoltaic/thermal system is proposed and studied. • The system presents an instantaneous electrical efficiency of 28%. • The system has a highest instantaneous thermal efficiency of 54%. • Direct irradiation has the dominant effect on the electrical performance. • Fitting results offer simple and reliable methods to analyze system performances. - Abstract: A high concentrator photovoltaic/thermal (HCPV/T) system based on point-focus Fresnel lens has been set up in this work. The concentrator has a geometric concentration ratio of 1090× and uniform irradiation distribution can be obtained on solar cells. The system produces both electricity and heat. Performance of the system has been investigated based on the outdoor measurement in a clear day. The HCPV/T system presents an instantaneous electrical efficiency of 28% and a highest instantaneous thermal efficiency of 54%, which means the overall efficiency of the system can be more than 80%. A mathematical model for calculating cell temperature is proposed to solve difficult measurement of cell temperature in a system. Moreover, characteristics of electrical performance under various direct

  1. Characterization of the InGaP/InGaAs/Ge triple-junction solar cell with a two-stage dish-style concentration system

    International Nuclear Information System (INIS)

    Wang, Zilong; Zhang, Hua; Wen, Dongsheng; Zhao, Wei; Zhou, Zhigang

    2013-01-01

    Highlights: • A mathematical model of triple-junction solar cell is established. • The calculated results compare well with outdoor experimental data. • A high efficiency heat pipe exchanger is specially designed to cool the cell. • The effect of the homogenizer is more significant at small direct solar radiation. • The impact of solar radiation on the experimental error is researched. - Abstract: Research on automatic tracking solar concentrator photovoltaic systems has gained increasing focus recently in order to develop high efficient solar PV technologies. A paraboloidal concentrator with a secondary optical system (with a concentration ratio in the range of 100–200×) and a sun tracking system was developed in this work. The performance of a heat-pipe cooled triple-junction GaInP/GalnAs/Ge solar cell was characterized. The experiments showed that the system achieved an average output power of 1.52 W/cm 2 and an average efficiency of 29.3% when average direct solar radiation is 450 W/m 2 , while keeping the maximum cell temperature below 64.9 °C, which were 23.3% and 9.1% higher than those of single stage concentrating system respectively. Moreover, the experimental error is increases with the solar radiation. The experimental results for V oc and I sc compared reasonable well with the predictions from a mathematical model, and the calculated values were out of the measured error, which suggested that the model can be used to analyze the influence of relevant parameters on the performance of high concentration photovoltaic systems

  2. Systems Biology Reveals Cigarette Smoke-Induced Concentration-Dependent Direct and Indirect Mechanisms That Promote Monocyte-Endothelial Cell Adhesion.

    Science.gov (United States)

    Poussin, Carine; Laurent, Alexandra; Peitsch, Manuel C; Hoeng, Julia; De Leon, Hector

    2015-10-01

    Cigarette smoke (CS) affects the adhesion of monocytes to endothelial cells, a critical step in atherogenesis. Using an in vitro adhesion assay together with innovative computational systems biology approaches to analyze omics data, our study aimed at investigating CS-induced mechanisms by which monocyte-endothelial cell adhesion is promoted. Primary human coronary artery endothelial cells (HCAECs) were treated for 4 h with (1) conditioned media of human monocytic Mono Mac-6 (MM6) cells preincubated with low or high concentrations of aqueous CS extract (sbPBS) from reference cigarette 3R4F for 2 h (indirect treatment, I), (2) unconditioned media similarly prepared without MM6 cells (direct treatment, D), or (3) freshly generated sbPBS (fresh direct treatment, FD). sbPBS promoted MM6 cells-HCAECs adhesion following I and FD, but not D. In I, the effect was mediated at a low concentration through activation of vascular inflammation processes promoted in HCAECs by a paracrine effect of the soluble mediators secreted by sbPBS-treated MM6 cells. Tumor necrosis factor α (TNFα), a major inducer, was actually shed by unstable CS compound-activated TNFα-converting enzyme. In FD, the effect was triggered at a high concentration that also induced some toxicity. This effect was mediated through an yet unknown mechanism associated with a stress damage response promoted in HCAECs by unstable CS compounds present in freshly generated sbPBS, which had decayed in D unconditioned media. Aqueous CS extract directly and indirectly promotes monocytic cell-endothelial cell adhesion in vitro via distinct concentration-dependent mechanisms. © The Author 2015. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  3. Thermal regeneration of an electrochemical concentration cell

    Science.gov (United States)

    Krumpelt, M.; Bates, J.K.

    1980-05-09

    A system and method are described for thermally regenerating an electrochemical concentration cell having first and second aluminum electrodes respectively positioned in contact with first and second electrolytes separated by an ion exchange member, the first and second electrolytes being composed of different concentrations of an ionic solvent and a salt, preferably an aluminum halide. The ionic solvent may be either organic or inorganic with a relatively low melting point, the ionic solvent and the salt form a complex wherein the free energy of formation of said complex is less than about -5 kcal/mole. A distillation column using solar heat or low grade industrial waste heat receives the first and second electrolytes and thermally decomposes the salt-solvent complex to provide feed material for the two half cells.

  4. Thermal regeneration of an electrochemical concentration cell

    Science.gov (United States)

    Krumpelt, Michael; Bates, John K.

    1981-01-01

    A system and method for thermally regenerating an electrochemical concentration cell having first and second aluminum electrodes respectively positioned in contact with first and second electrolytes separated by an ion exchange member, the first and second electrolytes being composed of different concentrations of an ionic solvent and a salt, preferably an aluminum halide. The ionic solvent may be either organic or inorganic with a relatively low melting point, the ionic solvent and the salt form a complex wherein the free energy of formation of said complex is less than about -5 Kcal/mole. A distillation column using solar heat or low grade industrial waste heat receives the first and second electrolytes and thermally decomposes the salt-solvent complex to provide feed material for the two half cells.

  5. Concentrated sunlight for organic solar cells

    DEFF Research Database (Denmark)

    Tromholt, Thomas

    2010-01-01

    . A high solar intensity study of inverted P3HT:PCBM solar cells is presented. Performance peak positions were found to be in the range of 1-5 suns, with smaller cells peaking at higher solar concentrations. Additionally, concentrated sunlight is demonstrated as a practical tool for accelerated stability...

  6. Cerebrospinal fluid concentration of erlotinib and its active metabolite OSI-420 in patients with central nervous system metastases of non-small cell lung cancer.

    Science.gov (United States)

    Togashi, Yosuke; Masago, Katsuhiro; Fukudo, Masahide; Terada, Tomohiro; Fujita, Shiro; Irisa, Kaoru; Sakamori, Yuichi; Kim, Young Hak; Mio, Tadashi; Inui, Ken-ichi; Mishima, Michiaki

    2010-07-01

    Although there have been several reports in which central nervous system (CNS) metastases of non-small cell lung cancer (NSCLC) were improved by erlotinib, cerebrospinal fluid (CSF) penetration of erlotinib in such patients has not been reported. We investigated CSF concentrations of erlotinib and its active metabolite OSI-420. We administered 150 mg erlotinib daily to four patients with NSCLC who had CNS metastases, and we investigated plasma pharmacokinetics of erlotinib and OSI-420 on days 1 and 8. In addition, we measured the concentrations of erlotinib and OSI-420 in CSF just before administration of erlotinib on day 8. In all cases except for one case, plasma pharmacokinetics data on day 8 were similar to those previously reported. The mean +/- SD CSF concentrations of erlotinib and OSI-420 were 54 +/- 30 ng/ml and 10.8 +/- 8.2 ng/ml, respectively. The mean +/- SD CSF penetration rates of erlotinib and OSI-420 were 5.1% +/- 1.9% and 5.8% +/- 3.6%, respectively. CSF concentrations of erlotinib exceeded median inhibitory concentration (IC50) of erlotinib in intact tumor cells with wild-type epidermal growth factor receptor gene. The CSF penetrations of erlotinib and OSI-420 in patients with NSCLC who had CNS metastases were approximately 5.1% and 5.8%, respectively. This indicates that erlotinib can become a treatment option for CNS metastases of NSCLC.

  7. Renewable Electricity Generation via Solar-Powered Methanol Reforming: Hybrid Proton Exchange Membrane Fuel Cell Systems Based on Novel Non-Concentrating, Intermediate-Temperature Solar Collectors

    Science.gov (United States)

    Real, Daniel J.

    Tremendous research efforts have been conducted studying the capturing and conversion of solar energy. Solar thermal power systems offer a compelling opportunity for renewable energy utilization with high efficiencies and excellent cost-effectiveness. The goal of this work was to design a non-concentrating collector capable of reaching temperatures above 250 °C, use this collector to power methanol steam reforming, and operate a proton exchange membrane (PEM) fuel cell using the generated hydrogen. The study presents the construction and characterization of a non-concentrating, intermediate-temperature, fin-in-tube evacuated solar collector, made of copper and capable of reaching stagnation temperatures of 268.5 °C at 1000 W/m2 irradiance. The collector was used to power methanol steam reforming, including the initial heating and vaporization of liquid reactants and the final heating of the gaseous reactants. A preferential oxidation (PROX) catalyst was used to remove CO from simulated reformate gas, and this product gas was used to operate a PEM fuel cell. The results show 1) that the outlet temperature is not limited by heat transfer from the absorber coating to the heat transfer fluid, but by the amount of solar energy absorbed. This implicates a constant heat flux description of the heat transfer process and allows for the usage of materials with lower thermal conductivity than copper. 2) It is possible to operate a PEM fuel cell from reformate gas if a PROX catalyst is used to remove CO from the gas. 3) The performance of the fuel cell is only slightly decreased (~4%) by CO2 dilution present in the reformate and PROX gas. These results provide a foundation for the first renewable electricity generation via solar-powered methanol reforming through a hybrid PEM fuel cell system based on novel non-concentrating, intermediate-temperature solar collectors.

  8. Concentrators Enhance Solar Power Systems

    Science.gov (United States)

    2013-01-01

    "Right now, solar electric propulsion is being looked at very seriously," says Michael Piszczor, chief of the photovoltaic and power technologies branch at Glen Research Center. The reason, he explains, originates with a unique NASA mission from the late 1990s. In 1998, the Deep Space 1 spacecraft launched from Kennedy Space Center to test a dozen different space technologies, including SCARLET, or the Solar Concentrator Array with Refractive Linear Element Technology. As a solar array that focused sunlight on a smaller solar cell to generate electric power, SCARLET not only powered Deep Space 1 s instruments but also powered its ion engine, which propelled the spacecraft throughout its journey. Deep Space 1 was the first spacecraft powered by a refractive concentrator design like SCARLET, and also utilized multi-junction solar cells, or cells made of multiple layers of different materials. For the duration of its 38-month mission, SCARLET performed flawlessly, even as Deep Space 1 flew by Comet Borrelly and Asteroid Braille. "Everyone remembers the ion engine on Deep Space 1, but they tend to forget that the SCARLET array powered it," says Piszczor. "Not only did both technologies work as designed, but the synergy between the two, solar power and propulsion together, is really the important aspect of this technology demonstration mission. It was the first successful use of solar electric propulsion for primary propulsion." More than a decade later, NASA is keenly interested in using solar electric propulsion (SEP) for future space missions. A key issue is cost, and SEP has the potential to substantially reduce cost compared to conventional chemical propulsion technology. "SEP allows you to use spacecraft that are smaller, lighter, and less costly," says Piszczor. "Even though it might take longer to get somewhere using SEP, if you are willing to trade time for cost and smaller vehicles, it s a good trade." Potentially, SEP could be used on future science missions

  9. Analysis of Photovoltaic Concentrating Solar Energy Systems

    OpenAIRE

    Garo Pilawjian

    2012-01-01

    In this paper the photovoltaic concentrating solar energy systems are analyzed. Both the Fresnel lens light refraction and mirror light reflection concentrating optical systems are considered. The main parameters and properties of photovoltaic concentrating solar energy systems are outlined. It is shown that the multi-parameter cost optimization is necessary to conduct to reduce the cost of photovoltaic concentrating solar energy systems.

  10. Experimental characterization of a concentrating photovoltaic system varying the light concentration

    International Nuclear Information System (INIS)

    Renno, C.; Petito, F.; Landi, G.; Neitzert, H.C.

    2017-01-01

    Highlights: • Experimental characterization of a concentrating photovoltaic system. • Analysis of the point-focus concentrating system performances. • Photovoltaic system parameters as function of the concentration factor. - Abstract: The concentrating photovoltaic system represents one of the most promising solar technologies because it allows a more efficient energy conversion. When a CPV system is designed, the main parameter which has to be considered is the concentration factor that affects both the system energy performances and its configuration. An experimental characterization of a CPV system previously realized at the University of Salerno, is presented in this paper considering several aspects related to the optical configuration, the concentration factor and the solar cell used. In particular, the parameters of an Indium Gallium Phosphide/Gallium Arsenide/Germanium triple-junction solar cell are investigated as function of the concentration factor determined by means of an experimental procedure that uses different optical configurations. The maximum concentration factor reached by the CPV system is 310 suns. The cell parameters dependence on the concentration is reported together with an electroluminescence analysis of the Indium Gallium Phosphide/Gallium Arsenide/Germanium cell. A monitoring of the electrical power provided by the system during its working is also presented corresponding to different direct irradiance values. A mean power of 2.95 W with an average efficiency of 32.8% is obtained referring to a mean irradiance of 930 W/m 2 ; lower values are obtained when the irradiance is highly fluctuating. The concentrating photovoltaic system electric energy output is estimated considering different concentration levels; the maximal obtained value is 23.5 W h on a sunny day at 310×. Finally, the temperature of the triple-junction solar cell is evaluated for different months in order to evaluate the potential annual thermal energy production

  11. In-line filtration of SAG-M red cell concentrates prepared in top/bottom or conventional bag systems.

    Science.gov (United States)

    Müller, N

    1996-01-01

    SAG-M RCCs were prepared in triple conventional or quadruple top/bottom bag systems and filtered at +4 degrees C using the in-line filter system Leucoflex LCR 4 Macopharma after 16-24-30 h of storage. Postfiltration WBC content was determined by Nageotte hemocytometer counting. The mean WBC content of the units prepared in conventional bag systems and filtered was higher than that of the units prepared in T/B bag systems. The best results could be obtained in T/B RCCs stored for 24 h; potassium and hemolysis levels were also improved. The Leucoflex LCR 4 in-line filter T/B system can be recommended for application in the clinical routine by virtue of the effective leukocyte elimination.

  12. Temperature optimization of high concentrated active cooled solar cells

    OpenAIRE

    Sabry, M.

    2016-01-01

    Active cooling is essential for solar cells operating under high optical concentration ratios. A system comprises four solar cells that are in thermal contact on top of a copper tube is proposed. Water is flowing inside the tube in order to reduce solar cells temperature for increasing their performance. Computational Fluid Dynamics (CFD) simulation of such system has been performed in order to investigate the effect of water flow rate, tube internal diameter, and convective heat transfer coe...

  13. Multijunction cells for concentrators: Technology prospects

    Science.gov (United States)

    Ferber, R. R. (Compiler); Costogue, E. N. (Compiler); Shimada, K. (Compiler)

    1984-01-01

    Development of high-efficiency multijunction solar cells for concentrator applications is a key step in achieving the goals of the U.S. Department of Energy National Photovoltaics Program. This report summarizes findings of an issue study conducted by the Jet Propulsion Laboratory Photovoltaic Analysis and Integration Center, with the assistance of the Solar Energy Research Institute and Sandia National laboratoies, which surveyed multijunction cell research for concentrators undertaken by federal agencies and by private industry. The team evaluated the potentials of research activities sponsored by DOE and by corporate funding to achieve projected high-efficiency goals and developed summary statements regarding industry expectations. Recommendations are made for the direction of future work to address specific unresolved aspects of multijunction cell technology.

  14. Multijunction solar cells for conversion of concentrated sunlight to electricity.

    Science.gov (United States)

    Kurtz, Sarah; Geisz, John

    2010-04-26

    Solar-cell efficiencies have exceeded 40% in recent years. The keys to achieving these high efficiencies include: 1) use of multiple materials that span the solar spectrum, 2) growth of these materials with near-perfect quality by using epitaxial growth on single-crystal substrates, and 3) use of concentration. Growth of near-perfect semiconductor materials is possible when the lattice constants of the materials are matched or nearly matched to that of a single-crystal substrate. Multiple material combinations have now demonstrated efficiencies exceeding 40%, motivating incorporation of these cells into concentrator systems for electricity generation. The use of concentration confers several key advantages.

  15. High-efficiency concentrator silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Sinton, R.A.; Cuevas, A.; King, R.R.; Swanson, R.M. (Stanford Univ., CA (USA). Solid-State Electronics Lab.)

    1990-11-01

    This report presents results from extensive process development in high-efficiency Si solar cells. An advanced design for a 1.56-cm{sup 2} cell with front grids achieved 26% efficiency at 90 suns. This is especially significant since this cell does not require a prismatic cover glass. New designs for simplified backside-contact solar cells were advanced from a status of near-nonfunctionality to demonstrated 21--22% for one-sun cells in sizes up to 37.5 cm{sup 2}. An efficiency of 26% was achieved for similar 0.64-cm{sup 2} concentrator cells at 150 suns. More fundamental work on dopant-diffused regions is also presented here. The recombination vs. various process and physical parameters was studied in detail for boron and phosphorous diffusions. Emitter-design studies based solidly upon these new data indicate the performance vs design parameters for a variety of the cases of most interest to solar cell designers. Extractions of p-type bandgap narrowing and the surface recombination for p- and n-type regions from these studies have a generality that extends beyond solar cells into basic device modeling. 68 refs., 50 figs.

  16. Lens refracting cost effective photovoltaic solar energy concentrating systems

    International Nuclear Information System (INIS)

    Pilawjian, G.A.

    2014-01-01

    The overall cost reduction task is studied for photovoltaic (PV) solar energy systems. For that purpose, a new, cost effective lens refracting system is developed. The concentrating system consists of Fresnel lenses placed under different facet angles refracting the sun light onto the solar cells placed along a line. The developed photovoltaic concentrating system uses the mathematical model of Fresnel lens concentrating optics for photovoltaic systems used to optimize the system by cost. A computer program FLCPVSys2.1 for the new concentrating system is developed allowing to design a photovoltaic system of the required power with the minimum cost. The program can be used for designing a cost effective photovoltaic solar concentrating system

  17. Instrumentation for accelerated life tests of concentrator solar cells.

    Science.gov (United States)

    Núñez, N; Vázquez, M; González, J R; Jiménez, F J; Bautista, J

    2011-02-01

    Concentrator photovoltaic is an emergent technology that may be a good economical and efficient alternative for the generation of electricity at a competitive cost. However, the reliability of these new solar cells and systems is still an open issue due to the high-irradiation level they are subjected to as well as the electrical and thermal stresses that they are expected to endure. To evaluate the reliability in a short period of time, accelerated aging tests are essential. Thermal aging tests for concentrator photovoltaic solar cells and systems under illumination are not available because no technical solution to the problem of reaching the working concentration inside a climatic chamber has been available. This work presents an automatic instrumentation system that overcomes the aforementioned limitation. Working conditions have been simulated by forward biasing the solar cells to the current they would handle at the working concentration (in this case, 700 and 1050 times the irradiance at one standard sun). The instrumentation system has been deployed for more than 10 000 h in a thermal aging test for III-V concentrator solar cells, in which the generated power evolution at different temperatures has been monitored. As a result of this test, the acceleration factor has been calculated, thus allowing for the degradation evolution at any temperature in addition to normal working conditions to be obtained.

  18. Simulation of an electrowetting solar concentration cell

    Science.gov (United States)

    Khan, Iftekhar; Rosengarten, Gary

    2015-09-01

    Electrowetting control of liquid lenses has emerged as a novel approach for solar tracking and concentration. Recent studies have demonstrated the concept of steering sunlight using thin electrowetting cells without the use of any bulky mechanical equipment. Effective application of this technique may facilitate designing thin and flat solar concentrators. Understanding the behavior of liquid-liquid and liquid-solid interface of the electrowetting cell through trial and error experimental processes is not efficient and is time consuming. In this paper, we present a simulation model to predict the liquid-liquid and liquid-solid interface behavior of electrowetting cell as a function of various parameters such as applied voltage, dielectric constant, cell size etc. We used Comsol Multiphysics simulations incorporating experimental data of different liquids. We have designed both two dimensional and three dimensional simulation models, which predict the shape of the liquid lenses. The model calculates the contact angle using the Young-Lippman equation and uses a moving mesh interface to solve the Navier-stokes equation with Navier slip wall boundary condition. Simulation of the electric field from the electrodes is coupled to the Young-Lippman equation. The model can also be used to determine operational characteristics of other MEMS electrowetting devices such as electrowetting display, optical switches, electronic paper, electrowetting Fresnel lens etc.

  19. Performance analysis of solar cell arrays in concentrating light intensity

    International Nuclear Information System (INIS)

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

    2009-01-01

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

  20. Tracking-integrated systems for concentrating photovoltaics

    Science.gov (United States)

    Apostoleris, Harry; Stefancich, Marco; Chiesa, Matteo

    2016-04-01

    Concentrating photovoltaic (CPV) systems, which use optical elements to focus light onto small-area solar cells, have the potential to minimize the costs, while improving efficiency, of photovoltaic technology. However, CPV is limited by the need to track the apparent motion of the Sun. This is typically accomplished using high-precision mechanical trackers that rotate the entire module to maintain normal light incidence. These machines are large, heavy and expensive to build and maintain, deterring commercial interest and excluding CPV from the residential market. To avoid this issue, some attention has recently been devoted to the development of tracking-integrated systems, in which tracking is performed inside the CPV module itself. This creates a compact system geometry that could be less expensive and more suitable for rooftop installation than existing CPV trackers. We review the basic tracking principles and concepts exploited in these systems, describe and categorize the existing designs, and discuss the potential impact of tracking integration on CPV cost models and commercial potential.

  1. Increasing the efficiency of fluorescent concentrator systems

    Energy Technology Data Exchange (ETDEWEB)

    Goldschmidt, Jan Christoph; Peters, Marius; Boesch, Armin; Helmers, Henning; Dimroth, Frank; Glunz, Stefan W.; Willeke, Gerhard [Fraunhofer Institute for Solar Energy Systems, Heidenhofstr. 2, 79110 Freiburg (Germany)

    2009-02-15

    This study examines concepts for increasing the efficiency of fluorescent concentrator systems. Different system sizes and configurations are investigated in detail by external quantum efficiency measurements, light-beam-induced current maps and by I-V measurements. A photonic structure that serves as a bandstop reflection filter for light emitted from dyes in the fluorescent concentrator increases the system efficiency relatively by 20%. Such photonic structures are especially beneficial for larger systems. The combination of two fluorescent concentrators made with different dyes in one stack increases the system efficiency from 5.1% with only one dye to 6.7% for the stack. (author)

  2. Hybrid photovoltaic and thermoelectric module for high concentration solar system

    Science.gov (United States)

    Tamaki, Ryo; Toyoda, Takeshi; Tamura, Yoichi; Matoba, Akinari; Minamikawa, Toshiharu; Tokuda, Masayuki; Masui, Megumi; Okada, Yoshitaka

    2017-09-01

    A photovoltaic (PV) and thermoelectric (TE) hybrid module was developed for application to high concentration solar systems. The waste heat from the solar cells under concentrated light illumination was utilized to generate additional electricity by assembling TE devices below the multi-junction solar cells (MJSCs). Considering the high operating temperature of the PV and TE hybrid module compared with conventional concentrator PV modules, the TE device could compensate a part of the MJSC efficiency degradation at high temperature. The performance investigation clarified the feasibility of the hybrid PV and TE module under highly concentrated sunlight illumination.

  3. Safety and Effectiveness of Bone Marrow Cell Concentrate in the Treatment of Chronic Critical Limb Ischemia Utilizing a Rapid Point-of-Care System

    Directory of Open Access Journals (Sweden)

    Venkatesh Ponemone

    2017-01-01

    Full Text Available Critical limb ischemia (CLI is the end stage of lower extremity peripheral vascular disease (PVD in which severe obstruction of blood flow results in ischemic rest pain, ulcers and/or gangrene, and a significant risk of limb loss. This open-label, single-arm feasibility study evaluated the safety and therapeutic effectiveness of autologous bone marrow cell (aBMC concentrate in revascularization of CLI patients utilizing a rapid point-of-care device. Seventeen (17 no-option CLI patients with ischemic rest pain were enrolled in the study. Single dose of aBMC, prepared utilizing an intraoperative point-of-care device, the Res-Q™ 60 BMC system, was injected intramuscularly into the afflicted limb and patients were followed up at regular intervals for 12 months. A statistically significant improvement in Ankle Brachial Index (ABI, Transcutaneous Oxygen Pressure (TcPO2, mean rest pain and intermittent claudication pain scores, wound/ ulcer healing, and 6-minute walking distance was observed following aBMC treatment. Major amputation-free survival (mAFS rate and amputation-free rates (AFR at 12 months were 70.6% and 82.3%, respectively. In conclusion, aBMC injections were well tolerated with improved tissue perfusion, confirming the safety, feasibility, and preliminary effectiveness of aBMC treatment in CLI patients.

  4. Simulation and development of a multi-leg homogeniser concentrating assembly for concentrated photovoltaic (CPV) system with electrical rating analysis

    KAUST Repository

    Burhan, Muhammad

    2016-03-09

    Concentrated photovoltaic (CPV) system utilizing multi-junction solar cells, is the main focus for current research, offering highest efficiency among all photovoltaic systems. The main aspect of CPV system is the design and performance of concentrating assembly, as it determines the performance of whole CPV system. However, the conventional design of CPV concentrating assembly dedicates one concentrator for each solar cell, in which single concentrator is capable to concentrate solar radiation onto single solar cell. This paper proposes a novel concentrating assembly for CPV system, which is designed to concentrate solar radiation onto four multi-junction solar cells with a single set of concentrators. The proposed design not only can reduce the number of concentrators and assembly efforts for CPV systems, but also achieved an acceptance angle of 1°. In this paper, the proposed multi-leg homogeniser CPV concentrating assembly is designed, developed, experimentally tested and verified through ray tracing simulation. The paper also discuss the development of mini, precise and accurate but cost effective two axis solar tracker for CPV system, which can be installed at any location even at rooftop of residential buildings, unlike conventional large scale CPV systems. Moreover, through the electrical rating analysis of the developed CPV system, its performance can be accurately estimated in any region. © 2016 Elsevier Ltd. All rights reserved.

  5. Status of concentrator collector and high-efficiency concentrator cell development

    Energy Technology Data Exchange (ETDEWEB)

    Gee, J.M.

    1990-01-01

    Photovoltaic concentrator collectors are an attractive option for utility-scale photovoltaic power plants. This paper reviews the current status of photovoltaic concentrator collector and cell development. Included in the review is a discussion of the economic motivation for concentrators, a summary of recent concentrator collector and cell development, and a description of a major new program to accelerate development and commercial introduction of concentrator collectors. 21 refs., 1 fig., 3 tabs.

  6. Optimization of concentrator photovoltaic solar cell performance through photonic engineering

    Energy Technology Data Exchange (ETDEWEB)

    Harris, James [Stanford Univ., CA (United States)

    2018-04-04

    The goal of this program was to incorporate two new and innovative design concepts into the design and production of CPV cells that have near zero added cost, yet significantly increase the operational efficiency of CPV modules. The program focused developing luminescent coupling effects and radiative cooling layers to increase efficiency and suppress CPV module power losses due to spectral variations and heating. The major results of the program were: 1) The optics of three commercial refractive (Fresnel) concentrators were characterized and prevent application of radiative cooling concepts due to strong mid-IR absorption (4-12µm) required to effectively radiate blackbody radiation from the cells and provide cooling. Investigation of alternative materials for the concentrator lenses produced only undesirable options—materials with reasonable mid-IR transmission for cooling only had about 30-40 visible transmission, thus reducing incident sunlight by >50%. While our investigation was somewhat limited, our work suggests that the only viable concentrator system that can incorporate radiative cooling utilizes reflective optics. 2) With limited ability to test high concentration CPV cells (requires outdoor testing), we acquired both semi-crystalline and crystalline Si cells and tested them in our outdoor facility and demonstrated 4°C cooling using a simple silica layer coating on the cells. 3) Characterizing Si cells in the IR associated with radiative cooling, we observed very significant near-IR absorption that increases the cell operating temperature by a similar amount, 4-5°C. By appropriate surface layer design, one can produce a layer that is highly reflective in the near-IR (1.5-4µm) and highly emissive in the mid-IR (5-15µm), thus reducing cell operational temperature by 10°C and increasing efficiency by ~1% absolute. The radiative cooling effect in c-Si solar cells might be further improved by providing a higher thermal conductive elastomer for

  7. Uranium concentration monitor manual: 2300 system

    International Nuclear Information System (INIS)

    Russo, P.A.; Sprinkle, J.K. Jr.; Stephens, M.M.

    1985-04-01

    This manual describes the design, operation, and procedures for measurement control for the automated uranium concentration monitor on the 2300 solvent extraction system at the Oak Ridge Y-12 Plant. The nonintrusive monitor provides a near-real time readout of uranium concentration at two locations simultaneously in the solvent extraction system for process monitoring and control. Detectors installed at the top of the extraction column and at the bottom of the backwash column acquire spectra of gamma rays from the solvent extraction solutions in the columns. Pulse-height analysis of these spectra gives the concentration of uranium in the organic product of the extraction column and in the aqueous product of the solvent extraction system. The visual readouts of concentrations for process monitoring are updated every 2 min for both detection systems. Simultaneously, the concentration results are shipped to a remote computer that has been installed by Y-12 to demonstrate automatic control of the solvent extraction system based on input of near-real time process operation information. 8 refs., 13 figs., 4 tabs

  8. Simulation and development of a multi-leg homogeniser concentrating assembly for concentrated photovoltaic (CPV) system with electrical rating analysis

    International Nuclear Information System (INIS)

    Burhan, Muhammad; Chua, Kian Jon Ernest; Ng, Kim Choon

    2016-01-01

    Highlights: • Novel multi-leg homogeniser concentrating assembly is developed for CPV system. • Single set of concentrator, concentrates sunlight on 4 MJCs with 1° acceptance angle. • The system performance is analyzed through experiment and ray tracing simulation. • Mini two axis solar tracker, with high tracking accuracy, is developed and tested. • Electrical rating analysis accurately estimates CPV system performance in any region. - Abstract: Concentrated photovoltaic (CPV) system utilizing multi-junction solar cells, is the main focus for current research, offering highest efficiency among all photovoltaic systems. The main aspect of CPV system is the design and performance of concentrating assembly, as it determines the performance of whole CPV system. However, the conventional design of CPV concentrating assembly dedicates one concentrator for each solar cell, in which single concentrator is capable to concentrate solar radiation onto single solar cell. This paper proposes a novel concentrating assembly for CPV system, which is designed to concentrate solar radiation onto four multi-junction solar cells with a single set of concentrators. The proposed design not only can reduce the number of concentrators and assembly efforts for CPV systems, but also achieved an acceptance angle of 1°. In this paper, the proposed multi-leg homogeniser CPV concentrating assembly is designed, developed, experimentally tested and verified through ray tracing simulation. The paper also discuss the development of mini, precise and accurate but cost effective two axis solar tracker for CPV system, which can be installed at any location even at rooftop of residential buildings, unlike conventional large scale CPV systems. Moreover, through the electrical rating analysis of the developed CPV system, its performance can be accurately estimated in any region.

  9. Technique for Outdoor Test on Concentrating Photovoltaic Cells

    Directory of Open Access Journals (Sweden)

    Paola Sansoni

    2015-01-01

    Full Text Available Outdoor experimentation of solar cells is essential to maximize their performance and to assess utilization requirements and limits. More generally tests with direct exposure to the sun are useful to understand the behavior of components and new materials for solar applications in real working conditions. Insolation and ambient factors are uncontrollable but can be monitored to know the environmental situation of the solar exposure experiment. A parallel characterization of the photocells can be performed in laboratory under controllable and reproducible conditions. A methodology to execute solar exposure tests is proposed and practically applied on photovoltaic cells for a solar cogeneration system. The cells are measured with concentrated solar light obtained utilizing a large Fresnel lens mounted on a sun tracker. Outdoor measurements monitor the effects of the exposure of two multijunction photovoltaic cells to focused sunlight. The main result is the continuous acquisition of the V-I (voltage-current curve for the cells in different conditions of solar concentration and temperature of exercise to assess their behavior. The research investigates electrical power extracted, efficiency, temperatures reached, and possible damages of the photovoltaic cell.

  10. A Concentrator Photovoltaic System Based on a Combination of Prism-Compound Parabolic Concentrators

    Directory of Open Access Journals (Sweden)

    Ngoc Hai Vu

    2016-08-01

    Full Text Available We present a cost-effective concentrating photovoltaic system composed of a prism and a compound parabolic concentrator (P-CPC. In this approach, the primary collector consists of a prism, a solid compound parabolic concentrator (CPC, and a slab waveguide. The prism, which is placed on the input aperture of CPC, directs the incoming sunlight beam to be parallel with the main axes of parabolic rims of CPC. Then, the sunlight is reflected at the parabolic rims and concentrated at the focal point of these parabolas. A slab waveguide is coupled at the output aperture of the CPC to collect focused sunlight beams and to guide them to the solar cell. The optical system was modeled and simulated with commercial ray tracing software (LightTools™. Simulation results show that the optical efficiency of a P-CPC can achieve up to 89%. when the concentration ratio of the P-CPC is fixed at 50. We also determine an optimal geometric structure of P-CPC based on simulation. Because of the simplicity of the P-CPC structure, a lower-cost mass production process is possible. A simulation based on optimal structure of P-CPC was performed and the results also shown that P-CPC has high angular tolerance for input sunlight. The high tolerance of the input angle of sunlight allows P-CPC solar concentrator utilize a single sun tracking system instead of a highly precise dual suntracking system as cost effective solution.

  11. Fourth-generation photovoltaic concentrator system development

    Energy Technology Data Exchange (ETDEWEB)

    O`Neill, M.J.; McDanal, A.J. [ENTECH, Inc., Dallas-Fort Worth Airport, TX (United States)

    1995-10-01

    In 1991, under a contract with Sandia for the Concentrator Initiative, the ENTECH team initiated the design and development of a fourth-generation concentrator module. In 1992, Sandia also contracted with ENTECH to develop a new control and drive system for the ENTECH array. This report documents the design and development work performed under both contracts. Manufacturing processes for the new module were developed at the same time under a complementary PVMaT contract with the National Renewable Energy Laboratory. Two 100-kW power plants were deployed in 1995 in Texas using the newly developed fourth-generation concentrator technology, one at the CSW Solar Park near Ft. Davis and one at TUE Energy Park in Dallas. Technology developed under the Sandia contracts has made a successful transition from the laboratory to the production line to the field.

  12. Towards operating direct methanol fuel cells with highly concentrated fuel

    Science.gov (United States)

    Zhao, T. S.; Yang, W. W.; Chen, R.; Wu, Q. X.

    A significant advantage of direct methanol fuel cells (DMFCs) is the high specific energy of the liquid fuel, making it particularly suitable for portable and mobile applications. Nevertheless, conventional DMFCs have to be operated with excessively diluted methanol solutions to limit methanol crossover and the detrimental consequences. Operation with diluted methanol solutions significantly reduces the specific energy of the power pack and thereby prevents it from competing with advanced batteries. In view of this fact, there exists a need to improve conventional DMFC system designs, including membrane electrode assemblies and the subsystems for supplying/removing reactants/products, so that both the cell performance and the specific energy can be simultaneously maximized. This article provides a comprehensive review of past efforts on the optimization of DMFC systems that operate with concentrated methanol. Based on the discussion of the key issues associated with transport of the reactants/products, the strategies to manage the supply/removal of the reactants/products in DMFC operating with highly concentrated methanol are identified. With these strategies, the possible approaches to achieving the goal of concentrated fuel operation are then proposed. Past efforts in the management of the reactants/products for implementing each of the approaches are also summarized and reviewed.

  13. High-concentration planar microtracking photovoltaic system exceeding 30% efficiency

    Science.gov (United States)

    Price, Jared S.; Grede, Alex J.; Wang, Baomin; Lipski, Michael V.; Fisher, Brent; Lee, Kyu-Tae; He, Junwen; Brulo, Gregory S.; Ma, Xiaokun; Burroughs, Scott; Rahn, Christopher D.; Nuzzo, Ralph G.; Rogers, John A.; Giebink, Noel C.

    2017-08-01

    Prospects for concentrating photovoltaic (CPV) power are growing as the market increasingly values high power conversion efficiency to leverage now-dominant balance of system and soft costs. This trend is particularly acute for rooftop photovoltaic power, where delivering the high efficiency of traditional CPV in the form factor of a standard rooftop photovoltaic panel could be transformative. Here, we demonstrate a fully automated planar microtracking CPV system 660× concentration ratio over a 140∘ full field of view. In outdoor testing over the course of two sunny days, the system operates automatically from sunrise to sunset, outperforming a 17%-efficient commercial silicon solar cell by generating >50% more energy per unit area per day in a direct head-to-head competition. These results support the technical feasibility of planar microtracking CPV to deliver a step change in the efficiency of rooftop solar panels at a commercially relevant concentration ratio.

  14. Radiative cooling for concentrating photovoltaic systems

    Science.gov (United States)

    Sun, Yubo; Zhou, Zhiguang; Jin, Xin; Sun, Xingshu; Alam, Muhammad Ashraful; Bermel, Peter

    2017-09-01

    Radiative cooling, a unique and uncommon passive cooling method for devices operating outdoors, has recently been demonstrated to be effective for photovoltaic thermal management. In this work, we investigate the effect of radiative cooling as a complement to existing passive cooling methods like convective cooling in a related system with much higher heat loads: a high-concentration photovoltaic (HCPV) system. A feasible radiative cooler design addressing the thermal management challenges here is proposed. It consists of low-iron soda-lime glass with a porous layer on top as an antireflection coating and a diamond layer as heat spreader. It is found that the proposed structure has strong mid-IR emittance as well as high solar transmission, allowing radiative cooling under direct sunlight and low loss in the concentrated solar irradiance. A systematic simulation with realistic considerations is then performed. Compared with a conventional copper cooler, the lowest temperature reached by the proposed radiative cooler is 14 K lower. Furthermore, less area of the proposed cooler is needed to reach a standard target temperature (333.15 K) for steady-state operation under high concentrations for the crystalline silicon PV module. In order to compare the coolers quantitatively, a figure of merit - cooling power per weight - is introduced. At the target temperature, the proposed cooler is determined to have a cooling power per weight of 75 W/kg, around 3.7 times higher than that of the conventional copper cooler.

  15. Linear concentration system; Sistema de concentracion lineal

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez Lugo, J.I; Leon Rovira, N; Aguayo Tellez, H [Instituto Tecnologico y de Estudios Superiores de Monterrey, Monterrey, Nuevo Leon (Mexico)]. E-mails: a00812662@itesm.mx; noel.leon@itesm.mx; haguayo@itesm.mx

    2013-03-15

    Solar linear concentration technologies to generate high temperatures are limited to the ranges of 200 to 500 degrees Celsius. While its performance has been tested through prototypes and pilot plants around the world, there are still areas of opportunity that can be exploited to obtain a linear concentration that achieves temperatures above this range in order to have a better use of the available solar energy. Because of this: It is possible to develop a linear concentration system that can track the sun with minimal movement of the absorber-receiver while maintaining temperatures above 850 degrees Celsius sufficient for industrial processes that require that temperature. The methodology consists of a series of stages (conceptual design, simulation, evaluation, development concept, results and validation) through which concepts are generated that allow design and evaluation of solar concentrator configurations with the help of simulation software. We have designed a linear parabolic concentrating system which comprises a set of mirrors segments with different focal lengths that works within the range of 600 degrees Celsius; however, it is advancing in the development of a double concentration to reach 850 degrees Celsius. [Spanish] Las tecnologias de concentracion lineal solar para generar altas temperaturas se ven limitadas a los rangos de 200 a 500 grados centigrados. Si bien su funcionamiento ha sido probado a traves de prototipos y plantas piloto alrededor del mundo, aun existen areas de oportunidad que pueden ser aprovechadas para obtener un sistema de concentracion lineal que permita alcanzar temperaturas mayores a este rango para asi tener un mejor aprovechamiento de la energia solar disponible. Debido a esto: Es posible desarrollar un sistema de concentracion lineal capaz de seguir la trayectoria del Sol con minimo movimiento del absorbedor-recibidor al mismo tiempo que mantiene temperaturas superiores a los 850 grados centigrados suficientes para

  16. Microfabricated ratchet structures for concentrating and patterning motile bacterial cells

    International Nuclear Information System (INIS)

    Kim, Sang Yub; Lee, Eun Se; Lee, Ho Jae; Lee, Se Yeon; Lee, Sung Kuk; Kim, Taesung

    2010-01-01

    We present a novel microfabricated concentrator for Escherichia coli that can be a stand-alone and self-contained microfluidic device because it utilizes the motility of cells. First of all, we characterize the motility of E. coli cells and various ratcheting structures that can guide cells to move in a desired direction in straight and circular channels. Then, we combine these ratcheting microstructures with the intrinsic tendency of cells to swim on the right side in microchannels to enhance the concentration rates up to 180 fold until the concentrators are fully filled with cells. Furthermore, we demonstrate that cells can be positioned and concentrated with a constant spacing distance on a surface, allowing spatial patterning of motile cells. These results can be applied to biosorption or biosensor devices that are powered by motile cells because they can be highly concentrated without any external mechanical and electrical energy sources. Hence, we believe that the concentrator design holds considerable potential to be applied for concentrating and patterning other motile microbes and providing a versatile structure for motility study of bacterial cells.

  17. Fabrication and performance analysis of concentrated hybrid photovoltaic system

    Directory of Open Access Journals (Sweden)

    Murthy Krishna

    2018-01-01

    Full Text Available Sun is the most important source of renewable source of energy. During the past few decades there has been an ever-increasing interest in Photovoltaic (PV cells as it directly converts solar radiation into electricity. This paper involves the performance study of photovoltaic system under concentrated solar radiation. The main problem with the concentration solar energy is the drastic increase in temperature of the photovoltaic module resulting in a decrease in performance efficiency of the system. This problem of overheating of the system can be overcome by providing cooling which would ensure operation of the module in the optimal temperature range. Hence, the setup would function as a hybrid model serving the dual purpose of power generation while also utilizing the waste heat for water heating applications. The experimental set up consist of a novel arrangement of concentrator and reflector and the cooling system. The Hybrid Photovoltaic System was repeatedly tested under real time conditions on several days. A comparison was drawn between the results obtained from direct exposure of a standard photovoltaic module to that obtained from the hybrid system in order to better understand the improvement in performance parameters. The study shown a significant improvement of output of standard photovoltaic module under the concentrated solar radiation.

  18. Monitoring of yeast cell concentration using a micromachined impedance sensor

    NARCIS (Netherlands)

    Krommenhoek, E.E.; Gardeniers, Johannes G.E.; Bomer, Johan G.; van den Berg, Albert; Li, X.; Ottens, M.; van der Wielen, L.A.M.; van Dedem, G.W.K.; van Leeuwen, M.; van Gulik, W.M.; Heijnen, J.J.

    2005-01-01

    The paper describes the design, modelling and experimental characterization of a micromachined impedance sensor for on-line monitoring of the viable yeast cell concentration (biomass) in a miniaturized cell assay. Measurements in a Saccharomyces cerevisiae cell culture show that the permittivity of

  19. Flexible thermal cycle test equipment for concentrator solar cells

    Science.gov (United States)

    Hebert, Peter H [Glendale, CA; Brandt, Randolph J [Palmdale, CA

    2012-06-19

    A system and method for performing thermal stress testing of photovoltaic solar cells is presented. The system and method allows rapid testing of photovoltaic solar cells under controllable thermal conditions. The system and method presents a means of rapidly applying thermal stresses to one or more photovoltaic solar cells in a consistent and repeatable manner.

  20. Assuring long-term reliability of concentrator PV systems

    Science.gov (United States)

    McConnell, R.; Garboushian, V.; Brown, J.; Crawford, C.; Darban, K.; Dutra, D.; Geer, S.; Ghassemian, V.; Gordon, R.; Kinsey, G.; Stone, K.; Turner, G.

    2009-08-01

    Concentrator PV (CPV) systems have attracted significant interest because these systems incorporate the world's highest efficiency solar cells and they are targeting the lowest cost production of solar electricity for the world's utility markets. Because these systems are just entering solar markets, manufacturers and customers need to assure their reliability for many years of operation. There are three general approaches for assuring CPV reliability: 1) field testing and development over many years leading to improved product designs, 2) testing to internationally accepted qualification standards (especially for new products) and 3) extended reliability tests to identify critical weaknesses in a new component or design. Amonix has been a pioneer in all three of these approaches. Amonix has an internal library of field failure data spanning over 15 years that serves as the basis for its seven generations of CPV systems. An Amonix product served as the test CPV module for the development of the world's first qualification standard completed in March 2001. Amonix staff has served on international standards development committees, such as the International Electrotechnical Commission (IEC), in support of developing CPV standards needed in today's rapidly expanding solar markets. Recently Amonix employed extended reliability test procedures to assure reliability of multijunction solar cell operation in its seventh generation high concentration PV system. This paper will discuss how these three approaches have all contributed to assuring reliability of the Amonix systems.

  1. Performance of planar heterojunction perovskite solar cells under light concentration

    Directory of Open Access Journals (Sweden)

    Aaesha Alnuaimi

    2016-11-01

    Full Text Available In this work, we present 2D simulation of planar heterojunction perovskite solar cells under high concentration using physics-based TCAD. The performance of planar perovskite heterojunction solar cells is examined up to 1000 suns. We analyze the effect of HTM mobility and band structure, surface recombination velocities at interfaces and the effect of series resistance under concentrated light. The simulation results revealed that the low mobility of HTM material limits the improvement in power conversation efficiency of perovskite solar cells under concentration. In addition, large band offset at perovskite/HTM interface contributes to the high series resistance. Moreover, losses due to high surface recombination at interfaces and the high series resistance deteriorate significantly the performance of perovskite solar cells under concentration.

  2. Continuous measurement of radon concentration in air with Lucas cell

    International Nuclear Information System (INIS)

    Machaj, B.; Urbanski, P.

    1998-01-01

    Lucas cell was investigated as alpha radiation detector for continuous measurement of radon concentration in air with air sampling by means of the pump. The investigations carried out indicate that short lived radon decay products inside of the Lucas chamber with dimensions φ54x74 mm (0.17L) attach to the internal walls of the cell and are not removed when the cell is flushed with fresh air. This effect and the known effect of increase of radon daughters concentration when pure radon is introduced into the cell results in delay of response of the gage to variations of radon concentration. The response of the gage is considered and signal processing is suggested that can be useful in continuous measurement of radon concentration. (author)

  3. Coupling of Luminescent Solar Concentrators to Plasmonic Solar Cells

    Science.gov (United States)

    Wang, Shu-Yi

    absorption at the emission peak of the dye. A factorial increase in the output power density of coupled PV as compared to PV exposed directly to solar spectrum is observed for high light concentration on the edge. These initial results motivated a more in-depth study of coupled LSC-PV system, which took into account the radiative transport inside the realistic LSC. These investigations were carried out on LSCs using Lumogen Red305 and Rhodamine 6G dyes coupled to pristine and plasmonic ultra-thin film silicon solar cells. Prediction based on detailed balance shows that the coupled LSC-plasmonic solar cell can generate 63.7 mW/cm2 with a photocurrent density of 71.3 mA/cm2 which is higher than that of cSi solar cells available on current market. The second part of the thesis focuses on PV absorption enhancement techniques. First, the effect of vertical positioning of plasmonic nanostructures on absorption enhancement was theoretically investigated to understand which one of the three mechanisms usually responsible for the enhancement (forward scattering, diffraction and localized surface plamson) plays the dominant role. Simulation results suggested that the maximum enhancement occurred when placing the nanostructures in the rear side of the cell because of longer path length due to scattering. The experimental effort then switched focus on substrate patterning, which is a less expensive alternative to plasmonic absorption enhancement. Specifically, a nanostructured substrate was prepared by a simple electrochemical process based on two-step aluminum anodization technique. The absorption of thin film silicon deposited on these substrates showed a broadband enhancement. The overall photocurrent density was up to 40% higher than that of films deposited on flat substrates. In conclusion, the studies carried out in this thesis indicate that spectral coupling of LSCs to thin film solar cells could lead to significant improvements in PV output power density. Moreover, while the

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

    International Nuclear Information System (INIS)

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

    2011-01-01

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

  5. Effect of autologous transplantation of bone marrow cells concentrated with the MarrowXpress system in patients with critical limb ischemia.

    Science.gov (United States)

    Maione, C; Botti, C; Coppola, C A; Silvestroni, C; Lillo, S; Schiavone, V; Sica, G; Sica, V; Kumar, V; Cobellis, G

    2013-01-01

    Critical limb ischemia (CLI), a vascular disease affecting lower limbs, with high morbidity and mortality, is becoming a challenge due to the aging of the population. Patients without direct revascularization options have the worst outcomes. To date, 25% to 40% of CLI patients are not candidates for surgical or endovascular approaches, facing a major amputation as the ultimate option. This study sought to assess the safety and efficacy of transplantation of autologous bone marrow concentrates in "no-option" patients to restore blood perfusion by collateral flow and limb salvage. We performed a nonrandomized, noncontrolled pilot study for no-option CLI patients using intra-arterial infusion of autologous bone marrow concentrate. Variation of blood perfusion parameters, evaluated by laser doppler flowmetry after 6 and 12 months, was set as primary endpoint. Thirteen enrolled patients showed improvements in objective measurements of perfusion. This uncontrolled study provided evidence that transplantation of autologous bone marrow concentrates was well tolerated by CLI patients without significant adverse effects, demonstrating improved perfusion, confirming the feasibility and safety of the procedure. Copyright © 2013 Elsevier Inc. All rights reserved.

  6. An energy analysis of a linear concentrating photovoltaic system with an active cooling system

    Science.gov (United States)

    Kerzmann, Tony L.; Schaefer, Laura A.

    2010-08-01

    The recent focus on renewable energy has lead to an increased awareness of solar energy. Concentrating photovoltaic systems have seen a resurgence in research interest since their earlier pilot plant origins in the 1970s and 1980s. The use of concentration reduces the amount of expensive photovoltaic materials while maintaining a high level of incident solar radiation. This research combines the advantage of concentrating solar energy with high efficiency multijunction cells and an active cooling system to create a system that efficiently produces both electricity and heat. A linear concentrating photovoltaic system model was developed in order to simulate the system under actual solar and climatic conditions, where a number of different system variables can be adjusted. This simulation was used to evaluate the effects of domestic hot water use on a 6.2 kWp system. The results show the changes in solar cell efficiency, electricity produced, thermal energy produced, dollar value displaced, and global warming potential displaced as the domestic hot water use of the system is varied. This simulation can be used to find an optimal system for given input conditions and can be used to find optimal operating conditions for a given system size.

  7. Pathway to 50% Efficient Inverted Metamorphic Concentrator Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Geisz, John F [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Steiner, Myles A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Jain, Nikhil [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Schulte, Kevin L [National Renewable Energy Laboratory (NREL), Golden, CO (United States); France, Ryan M [National Renewable Energy Laboratory (NREL), Golden, CO (United States); McMahon, William E [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Perl, Emmett [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Horowitz, Kelsey A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Friedman, Daniel J [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-09-06

    Series-connected five (5J) and six junction (6J) concentrator solar cell strategies have the realistic potential to exceed 50% efficiency to enable low-cost CPV systems. We propose three strategies for developing a practical 6J device. We have overcome many of the challenges required to build such concentrator solar cell devices: We have developed 2.1 eV AlGaInP, 1.7 eV AlGaAs, and 1.7 eV GaInAsP junctions with external radiative efficiency greater than 0.1%. We have developed a transparent tunnel junction that absorbs minimal light intended for the second junction yet resists degradation under thermal load. We have developed metamorphic grades from the GaAs to the InP lattice constant that are transparent to sub-GaAs bandgap light. We have grown and compared low bandgap junctions (0.7eV - 1.2 eV) using metamorphic GaInAs, metamorphic GaInAsP, and GaInAsP lattice-matched to InP. And finally, we have demonstrated excellent performance in a high voltage, low current 4 junction inverted metamorphic device using 2.1, 1.7, 1.4, and 1.1 eV junctions with over 8.7 mA/cm2 one-sun current density that operates up to 1000 suns without tunnel junction failure.

  8. Counter-flow elutriation of clinical peripheral blood mononuclear cell concentrates for the production of dendritic and T cell therapies

    OpenAIRE

    Stroncek, David F; Fellowes, Vicki; Pham, Chauha; Khuu, Hanh; Fowler, Daniel H; Wood, Lauren V; Sabatino, Marianna

    2014-01-01

    Introduction Peripheral blood mononuclear cells (PBMC) concentrates collected by apheresis are frequently used as starting material for cellular therapies, but the cell of interest must often be isolated prior to initiating manufacturing. Study design and methods The results of enriching 59 clinical PBMC concentrates for monocytes or lymphocytes from patients with solid tumors or multiple myeloma using a commercial closed system semi-automated counter-flow elutriation instrument (Elutra, Teru...

  9. Cell suspension concentration monitoring by using a miniaturized serial high frequency SAWR sensor

    OpenAIRE

    Li, Jian; Feng, Hailin; Fang, Yiming

    2015-01-01

    In this paper, a miniaturized cell suspension concentration monitoring method was investigated. The sensing unit was a carbon screen-printed electrode (CSPE) in serial with a 433MHz vacuum-packaged surface acoustic wave resonator (SAWR). SAWR provided a stable and high operating frequency, which helps to keep the stability and sensitivity of the monitoring system. Living cells suspensions in different concentrations were prepared and dropcast on CSPE. Frequency responses of the sensor were re...

  10. Flat plate vs. concentrator solar photovoltaic cells - A manufacturing cost analysis

    Science.gov (United States)

    Granon, L. A.; Coleman, M. G.

    1980-01-01

    The choice of which photovoltaic system (flat plate or concentrator) to use for utilizing solar cells to generate electricity depends mainly on the cost. A detailed, comparative manufacturing cost analysis of the two types of systems is presented. Several common assumptions, i.e., cell thickness, interest rate, power rate, factory production life, polysilicon cost, and direct labor rate are utilized in this analysis. Process sequences, cost variables, and sensitivity analyses have been studied, and results of the latter show that the most important parameters which determine manufacturing costs are concentration ratio, manufacturing volume, and cell efficiency. The total cost per watt of the flat plate solar cell is $1.45, and that of the concentrator solar cell is $1.85, the higher cost being due to the increased process complexity and material costs.

  11. Accelerated Life Test for Photovoltaic Cells Using Concentrated Light

    Directory of Open Access Journals (Sweden)

    Daniel Tudor Cotfas

    2016-01-01

    Full Text Available This paper presents a new method developed to significantly reduce the necessary time for the ageing tests for different types of photovoltaic cells. Two ageing factors have been applied to the photovoltaic cells: the concentrated light and the temperature. The maximum power of the photovoltaic cells was monitored during the ageing process. The electrical dc and ac parameters of the photovoltaic cells were measured and analyzed at 1 sun irradiance, before and after the test stress. During the test, two photovoltaic cells are kept at maximum power point and the other two are kept at open circuit voltage point. The method is validated through the results obtained for the monocrystalline silicon solar cell.

  12. Methods and systems for concentrated solar power

    Science.gov (United States)

    Ma, Zhiwen

    2016-05-24

    Embodiments described herein relate to a method of producing energy from concentrated solar flux. The method includes dropping granular solid particles through a solar flux receiver configured to transfer energy from concentrated solar flux incident on the solar flux receiver to the granular solid particles as heat. The method also includes fluidizing the granular solid particles from the solar flux receiver to produce a gas-solid fluid. The gas-solid fluid is passed through a heat exchanger to transfer heat from the solid particles in the gas-solid fluid to a working fluid. The granular solid particles are extracted from the gas-solid fluid such that the granular solid particles can be dropped through the solar flux receiver again.

  13. Concentration of Cupriavidus necator cells by flocculation and sedimentation.

    Science.gov (United States)

    Finkler, Leandro; Luna-Finkler, Christine Lamenha; Pinto, José Carlos; Alves, Tito Livio Moitinho

    2007-12-01

    Separation and cells concentration constitute important stages in most biotechnological processes. Particularly, use of flocculation/sedimentation can improve significantly the extraction of biopolymers accumulated by microorganisms and the biodegradation of xenobiotic compounds by cell sludge. In this work the use of tannin and aluminum sulphate (Al2(SO4)3) as flocculating agents for concentration of cells of Cupriavidus necator DSM 545 is evaluated. Cells were grown in broth nutrient medium in Erlenmeyer flasks, submitted to orbital agitation of 160 rpm at 30 °C for 21 h. The optimal concentrations of flocculating agents, as determined with a standard jar test method, were equal to 2,800 mg/L for tannin and 800 mg/L for Al2(SO4)3, allowing for recovery of 95% of the cells in both cases. Obtained flocs presented density and average diameter of 1.03 g/mL ± 0.01 g/mL and 158 μm ± 19 μm for tannin and of 1.05 g/mL ± 0.01 g/mL and 146 μm ± 14 μm for Al2(SO4)3, respectively. Batch settling tests were performed in order to determine the operational capacity of continuous settlers to be used for separation of the investigated flocculent suspensions. Finally, cultivation of cells using flocs as inoculum indicated that the cells remained viable after flocculation with usage of the optimum flocculating agent concentrations.

  14. Fuel cell systems

    International Nuclear Information System (INIS)

    Kotevski, Darko

    2003-01-01

    Fuel cell systems are an entirely different approach to the production of electricity than traditional technologies. They are similar to the batteries in that both produce direct current through electrochemical process. There are six types of fuel cells each with a different type of electrolyte, but they all share certain important characteristics: high electrical efficiency, low environmental impact and fuel flexibility. Fuel cells serve a variety of applications: stationary power plants, transport vehicles and portable power. That is why world wide efforts are addressed to improvement of this technology. (Original)

  15. Reversible degradation of inverted organic solar cells by concentrated sunlight

    DEFF Research Database (Denmark)

    Tromholt, Thomas; Manor, Assaf; Katz, Eugene A

    2011-01-01

    Concentrated sunlight was used to study the performance response of inverted P3HT:PCBM organic solar cells after exposure to high intensity sunlight. Correlations of efficiency as a function of solar intensity were established in the range of 0.5–15 suns at three different stages: for a pristine...

  16. Concentration Impedance in Testing of Solid Oxide Cells Revisited

    DEFF Research Database (Denmark)

    Mogensen, Mogens Bjerg; Ebbesen, Sune Dalgaard; Jensen, Søren Højgaard

    2017-01-01

    The concentration impedance originating from diffusion and reactant conversion impedance of the Ni-YSZ supported fuel electrode in solid oxide cell has been treated many times during the latest couple of decades. In spite of this, the separation of the diffusion impedance from the conversion...

  17. Thermal Analysis of Direct Liquid-Immersed Solar Receiver for High Concentrating Photovoltaic System

    Directory of Open Access Journals (Sweden)

    Xinyue Han

    2015-01-01

    Full Text Available Concentrator solar cells that operate at high solar concentration level must be cooled. In this paper, direct liquid immersion cooling of triple-junction solar cells (InGaP/InGaAs/Ge is proposed as a heat dissipation solution for dense-array high concentrating photovoltaic (HCPV systems. The advantages of triple-junction CPV cells immersed in a circulating dielectric liquid and dish HCPV technology are integrated into a CPV system to improve the system electrical conversion efficiency. An analytical model for the direct liquid-immersed solar receiver with triple-junction CPV cells is presented. The main outputs of the model are the components temperatures of the receiver and the system electrical efficiency. The influence of concentration factor, mass flow rate, and inlet liquid temperature on the operating temperature of the triple-junction CPV cells and the system electrical conversion efficiency are discussed. It is shown that the system electrical conversion efficiency is very high for a wide range of operating conditions. The three operating parameters have a major effect on the operating temperature of the triple-junction CPV cells and, by extension, system output power. The flow rate selection should match concentration factor to keep the triple-junction CPV cells temperature lower and increase the electrical conversion efficiency of the dense-array HCPV system.

  18. A compact multiparameter acquisition system for radon concentration studies

    Science.gov (United States)

    Pugliese; Baiano; Boiano; D'Onofrio; Roca; Sabbarese; Vollaro

    2000-07-01

    A compact device suitable to acquire and display, at the same time, radon concentrations in a given atmosphere, and the environmental parameters characterising the atmosphere, is presented and described. It consists of two main blocks: (i) a detection section including a set of sensors for measuring pressure, humidity and temperature, and a set of silicon surface barrier detectors mounted in electrostatic cells collecting the ionised radon daughters; (ii) a single NIM module featuring an eight channel 12 bit ADC and the linear electronics to shape the signals from the silicon detectors. The system is controlled by a computer via a RS232 port. The software, implemented in Visual Basic, allows to display the energy distribution of the pulses coming from the alpha detectors and to initialise and control all phases of the acquisition. The results of preliminary tests show the high reliability of the system.

  19. A compact multiparameter acquisition system for radon concentration studies

    International Nuclear Information System (INIS)

    Pugliese, M.; Baiano, G.; Boiano, A.; D'Onofrio, A.; Roca, V.; Sabbarese, C.; Vollaro, P.

    2000-01-01

    A compact device suitable to acquire and display, at the same time, radon concentrations in a given atmosphere, and the environmental parameters characterising the atmosphere, is presented and described. It consists of two main blocks: (i) a detection section including a set of sensors for measuring pressure, humidity and temperature, and a set of silicon surface barrier detectors mounted in electrostatic cells collecting the ionised radon daughters; (ii) a single NIM module featuring an eight channel 12 bit ADC and the linear electronics to shape the signals from the silicon detectors. The system is controlled by a computer via a RS232 port. The software, implemented in Visual Basic, allows to display the energy distribution of the pulses coming from the alpha detectors and to initialise and control all phases of the acquisition. The results of preliminary tests show the high reliability of the system

  20. Hemicellulosic ethanol production by immobilized cells of Scheffersomyces stipitis: effect of cell concentration and stirring.

    Science.gov (United States)

    Milessi, Thais S S; Antunes, Felipe A F; Chandel, Anuj K; da Silva, Silvio S

    2015-01-01

    Bioconversion of hemicellulosic hydrolysate into ethanol plays a pivotal role in the overall success of biorefineries. For the efficient fermentative conversion of hemicellulosic hydrolysates into ethanol, the use of immobilized cells system could provide the enhanced ethanol productivities with significant time savings. Here, we investigated the effect of 2 important factors (e.g., cell concentration and stirring) on ethanol production from sugarcane bagasse hydrolysate using the yeast Scheffersomyces stipitis immobilized in calcium alginate matrix. A 2(2) full factorial design of experiment was performed considering the process variables- immobilized cell concentration (3.0, 6.5 and 10.0 g/L) and stirring (100, 200 and 300 rpm). Statistical analysis showed that stirring has the major influence on ethanol production. Maximum ethanol production (8.90 g/l) with ethanol yield (Yp/s) of 0.33 g/g and ethanol productivity (Qp) of 0.185 g/l/h was obtained under the optimized process conditions (10.0 g/L of cells and 100 rpm).

  1. Optimization of a Point Focus Concentration Photovoltaic System with Passive Cooling

    International Nuclear Information System (INIS)

    Chenlo, F.

    2015-01-01

    The objective of this work is modeling the temperature of photovoltaic (PV) solar cells operating in concentration systems with circular geometry and coupled to a heat sink plate for passive cooling. The proposed thermal behavior model analyses the temperature surface distribution of both PV solar cell and heat sink plate as function of light concentration. The model also allows analyzing the influence of other parameters such as uniform and non-uniform variation of the heat sink plate thickness or variation of the thermal transmission coefficient. The optimal range of the concentration factor is studied using simple models for the PV solar cell efficiency and Fresnel lens concentrator performance together with a function of costs applied to medium concentration silicon crystalline PV cells and high efficiency and high concentration multi-junction PV cells. Finally, experimental main parameters and its procedures measurement for concentration systems are presented. Modeling results show that the use of a high conductivity disk thermally coupled between the rear side of the cell and the cooling plate reduces the working cell temperature. Results also indicates that use of a light redirecting prism by total internal reflection of sunlight, reduces optical losses due to concentrator defects and chromatic aberration and increases the angle tracking error acceptance without having to increase the area of the PV solar cell

  2. A concentrator module of spherical Si solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Zhengxin; Masuda, Atsushi; Nagai, Takehiko; Kondo, Michio [Research Center for Photovoltaics, National Institute of Advanced Industrial Science and Technology (AIST), Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568 (Japan); Miyazaki, Takashi; Takano, Miwako; Takano, Masahiro; Yoshigahara, Haruyuki [Techno Frontier Tsukuba, Japan Gore-Tex Inc., 5-5 Tokodai, Tsukuba, Ibaraki 300-2635 (Japan); Sakai, Kazutoshi; Asai, Koichi [Fuji Machine Manufacture Co. Ltd., 480 Tojiri, Hasama, Toyota, Aichi 470-0452 (Japan)

    2007-11-23

    Spherical Si solar cell, which is made up of Si spheres with a diameter of approximately 1.0 mm, is expected to be a promising candidate for low consumption of Si feedstock and simple process technology. This paper describes the formation process and the structure of a concentrator module in detail. The concentrator lens was formed by casting with ultraviolet light hardening resin. The concentration ratio was 4.4 times and the pitch between the spheres was 2.0 mm. By this module design, it was possible to realize a consumption of the Si feedstock of about 3.0 g/W. Conversion efficiencies of 11.3% from single-sphere cell, 8.5% from a 23-spheres module and 5.2% from a 105-spheres module under AM1.5, 100 mW/cm{sup 2} illumination were achieved. (author)

  3. Thermal analysis of a multi-layer microchannel heat sink for cooling concentrator photovoltaic (CPV) cells

    Science.gov (United States)

    Siyabi, Idris Al; Shanks, Katie; Mallick, Tapas; Sundaram, Senthilarasu

    2017-09-01

    Concentrator Photovoltaic (CPV) technology is increasingly being considered as an alternative option for solar electricity generation. However, increasing the light concentration ratio could decrease the system output power due to the increase in the temperature of the cells. The performance of a multi-layer microchannel heat sink configuration was evaluated using numerical analysis. In this analysis, three dimensional incompressible laminar steady flow model was solved numerically. An electrical and thermal solar cell model was coupled for solar cell temperature and efficiency calculations. Thermal resistance, solar cell temperature and pumping power were used for the system efficiency evaluation. An increase in the number of microchannel layers exhibited the best overall performance in terms of the thermal resistance, solar cell temperature uniformity and pressure drop. The channel height and width has no effect on the solar cell maximum temperature. However, increasing channel height leads to a reduction in the pressure drop and hence less fluid pumping power.

  4. Field test analysis of concentrator photovoltaic system focusing on average photon energy and temperature

    Science.gov (United States)

    Husna, Husyira Al; Ota, Yasuyuki; Minemoto, Takashi; Nishioka, Kensuke

    2015-08-01

    The concentrator photovoltaic (CPV) system is unique and different from the common flat-plate PV system. It uses a multi-junction solar cell and a Fresnel lens to concentrate direct solar radiation onto the cell while tracking the sun throughout the day. The cell efficiency could reach over 40% under high concentration ratio. In this study, we analyzed a one year set of environmental condition data of the University of Miyazaki, Japan, where the CPV system was installed. Performance ratio (PR) was discussed to describe the system’s performance. Meanwhile, the average photon energy (APE) was used to describe the spectrum distribution at the site where the CPV system was installed. A circuit simulator network was used to simulate the CPV system electrical characteristics under various environmental conditions. As for the result, we found that the PR of the CPV systems depends on the APE level rather than the cell temperature.

  5. System for particle concentration and detection

    Science.gov (United States)

    Morales, Alfredo M.; Whaley, Josh A.; Zimmerman, Mark D.; Renzi, Ronald F.; Tran, Huu M.; Maurer, Scott M.; Munslow, William D.

    2013-03-19

    A new microfluidic system comprising an automated prototype insulator-based dielectrophoresis (iDEP) triggering microfluidic device for pathogen monitoring that can eventually be run outside the laboratory in a real world environment has been used to demonstrate the feasibility of automated trapping and detection of particles. The system broadly comprised an aerosol collector for collecting air-borne particles, an iDEP chip within which to temporarily trap the collected particles and a laser and fluorescence detector with which to induce a fluorescence signal and detect a change in that signal as particles are trapped within the iDEP chip.

  6. Biaxial-Type Concentrated Solar Tracking System with a Fresnel Lens for Solar-Thermal Applications

    OpenAIRE

    Tsung Chieh Cheng; Chao Kai Yang; I Lin

    2016-01-01

    In this paper, an electromechanical, biaxial-type concentrated solar tracking system was designed for solar-thermal applications. In our tracking system, the sunlight was concentrated by the microstructure of Fresnel lens to the heating head of the Stirling engine and two solar cells were installed to provide the power for tracking system operation. In order to obtain the maximum sun power, the tracking system traces the sun with the altitude-azimuth biaxial tracing method and accurately main...

  7. The World's Largest Photovoltaic Concentrator System.

    Science.gov (United States)

    Smith, Harry V.

    1982-01-01

    The Mississippi County Community College large-scale energy experiment, featuring the emerging high technology of solar electricity, is described. The project includes a building designed for solar electricity and a power plant consisting of a total energy photovoltaic system, and features two experimental developments. (MLW)

  8. Mechanically Stacked Four-Junction Concentrator Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Steiner, Myles A.; Geisz, John F.; Ward, J. Scott; Garcia, Ivan; Friedman, Daniel J.; King, Richard R.; Chiu, Philip T.; France, Ryan M.; Duda, Anna; Olavarria, Waldo J.; Young, Michelle; Kurtz, Sarah R.

    2015-06-14

    Multijunction solar cells can be fabricated by bonding together component cells that are grown separately. Because the component cells are each grown lattice-matched to suitable substrates, this technique allows alloys of different lattice constants to be combined without the structural defects introduced when using metamorphic buffers. Here we present results on the fabrication and performance of four-junction mechanical stacks composed of GaInP/GaAs and GaInAsP/GaInAs tandems, grown on GaAs and InP substrates, respectively. The two tandems were bonded together with a low-index, transparent epoxy that acts as an omni-directional reflector to the GaAs bandedge luminescence, while simultaneously transmitting nearly all of the sub-bandgap light. As determined by electroluminescence measurements and optical modeling, the GaAs subcell demonstrates a higher internal radiative limit and thus higher subcell voltage, compared with GaAs subcells without enhanced internal optics; all four subcells exhibit excellent material quality. The device was fabricated with four contact terminals so that each tandem can be operated at its maximum power point, which raises the cumulative efficiency and decreases spectral sensitivity. Efficiencies exceeding 38% at one-sun have been demonstrated. Eliminating the series resistance is the key challenge for the concentrator cells. We will discuss the performance of one-sun and concentrator versions of the device, and compare the results to recently fabricated monolithic four-junction cells.

  9. Energy Yield Determination of Concentrator Solar Cells using Laboratory Measurements: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Geisz, John F.; Garcia, Ivan; McMahon, William E.; Steiner, Myles A.; Ochoa, Mario; France, Ryan M.; Habte, Aron; Friedman, Daniel J.

    2015-09-14

    The annual energy conversion efficiency is calculated for a four junction inverted metamorphic solar cell that has been completely characterized in the laboratory at room temperature using measurements fit to a comprehensive optoelectronic model of the multijunction solar cells. A simple model of the temperature dependence is used to predict the performance of the solar cell under varying temperature and spectra characteristic of Golden, CO for an entire year. The annual energy conversion efficiency is calculated by integrating the predicted cell performance over the entire year. The effects of geometric concentration, CPV system thermal characteristics, and luminescent coupling are highlighted. temperature and spectra characteristic of Golden, CO for an entire year. The annual energy conversion efficiency is calculated by integrating the predicted cell performance over the entire year. The effects of geometric concentration, CPV system thermal characteristics, and luminescent coupling are highlighted.

  10. Flight Experience from Space Photovoltaic Concentrator Arrays and its Implication on Terrestrial Concentrator Systems

    Science.gov (United States)

    Piszczor, Michael F., Jr.

    2003-01-01

    Nearly all photovoltaic solar arrays flown in space have used a planar (non- concentrating) design. However, there have been a few notable exceptions where photovoltaic concentrators have been tested and used as the mission s primary power source. Among these are the success experienced by the SCARLET (Solar Concentrator Array with Refractive Linear Element Technology) concept used to power NASA's Deep Space 1 mission and the problems encountered by the original Boeing 702 reflective trough concentrator design. This presentation will give a brief overview of past photovoltaic concentrator systems that have flown in space, specifically addressing the valuable lessons learned from flight experience, and other viable concentrator concepts that are being proposed for the future. The general trends of this flight experience will be noted and discussed with regard to its implications on terrestrial photovoltaic concentrator designs.

  11. Concentrate composition for automatic milking systems - effect on milking frequency

    DEFF Research Database (Denmark)

    Madsen, Jørgen; Weisbjerg, Martin Riis; Hvelplund, Torben

    2010-01-01

    The purpose of this study was to investigate the potential of affecting milking frequency in an Automatic Milking System (AMS) by changing ingredient composition of the concentrate fed in the AMS. In six experiments, six experimental concentrates were tested against a Standard concentrate all sup...

  12. An advanced space photovoltaic concentrator array using Fresnel lenses, gallium arsenide cells, and prismatic cell covers

    Science.gov (United States)

    O'Neill, Mark J.; Piszczor, Michael F.

    1988-01-01

    The current status of a space concentrator array which uses refractive optics, gallium arsenide cells, and prismatic cell covers to achieve excellent performance at a very low array mass is documented. The prismatically covered cells have established records for space cell performance (24.2 percent efficient at 100 AM0 suns and 25 C) and terrestrial single-junction cell performance (29.3 percent efficient at 200 AM1.5 suns and 25 C).

  13. Optimum Concentration Ratio Analysis Using Dynamic Thermal Model for Concentrated Photovoltaic System

    Science.gov (United States)

    2012-03-22

    different semiconductor material solar cells, such as GaAs, InGaP, CdTe , and other high-efficiency cell materials to investigate the thermal properties...Technology. Norwell, MA : Kluwer Academic Publishers, 1997. 39. Model of Photovoltaic Module in MATLAB. Gonzalez-Longatt, Francisco M. 2DO Congreso...of Hong Kong, 2010. 44. A Simple Passive Cooling Structure and its Heat Analysis for 500 X Concentration PV Module . Araki, Kenji, Uozumi, Hisafumi

  14. Hyaluronan scaffold supports osteogenic differentiation of bone marrow concentrate cells.

    Science.gov (United States)

    Cavallo, C; Desando, G; Ferrari, A; Zini, N; Mariani, E; Grigolo, B

    2016-01-01

    Osteochondral lesions are considered a challenge for orthopedic surgeons. Currently, the treatments available are often unsatisfactory and unable to stimulate tissue regeneration. Tissue engineering offers a new therapeutic strategy, taking into account the role exerted by cells, biomaterial and growth factors in restoring tissue damage. In this light, Mesenchymal Stem Cells (MSCs) have been indicated as a fascinating tool for regenerative medicine thanks to their ability to differentiate into bone, cartilage and adipose tissue. However, in vitro-cultivation of MSCs could be associated with some risks such as de-differentiation/reprogramming, infection and contaminations of the cells. To overcome these shortcomings, a new approach is represented by the use of Bone Marrow Concentrate (BMC), that could allow the delivery of cells surrounded by their microenvironment in injured tissue. For this purpose, cells require a tridimensional scaffold that can support their adhesion, proliferation and differentiation. This study is focused on the potentiality of BMC seeded onto a hyaluronan-based scaffold (Hyaff-11) to differentiate into osteogenic lineage. This process depends on the specific interaction between cells derived from bone marrow (surrounded by their niche) and scaffold, that create an environment able to support the regeneration of damaged tissue. The data obtained from the present study demonstrate that BMC grown onto Hyaff-11 are able to differentiate toward osteogenic sense, producing specific osteogenic genes and matrix proteins.

  15. Terrestrial photovoltaic power systems with sunlight concentration. Annual progress report, January 1, 1975--December 31, 1975

    Energy Technology Data Exchange (ETDEWEB)

    Backus, C.E.

    1976-01-31

    This annual report is for the second year of a program to investigate the characteristics of the components and the total system using sunlight concentrated onto solar cells. The second year was primarily to experimentally investigate the conclusions of the first year of analytical studies. Cells have been fabricated that are designed for different intensities. Typically the efficiency of a cell will increase from its 11 percent at AM1 peak to efficiency at the designed concentration level and return to its initial efficiency at about 3 times its designed concentration level. The developed cells have been tested under high intensity simulators and in concentrated sunlight and have shown to have the predicted response. The experimental testing of passive cooling limitations for cooling cells with just finned arrangements in the back of the cell has been completed in the controlled environment of a wind tunnel. These experiments have confirmed the heat transfer coefficients that had been used in the analytical studies. Testing was done to collect heat transfer coefficients for actual wind conditions and these data show good agreement with the controlled wind tunnel data. Four photovoltaic/concentrator system experiments have been started with CR of about 3, 10, 25, and 100. System analysis has indicated that photovoltaic concentration systems may be attractive in low solar irradiation areas such as Cleveland.

  16. GaAs quantum dot solar cell under concentrated radiation

    International Nuclear Information System (INIS)

    Sablon, K.; Little, J. W.; Hier, H.; Li, Y.; Mitin, V.; Vagidov, N.; Sergeev, A.

    2015-01-01

    Effects of concentrated solar radiation on photovoltaic performance are investigated in well-developed GaAs quantum dot (QD) solar cells with 1-Sun efficiencies of 18%–19%. In these devices, the conversion processes are enhanced by nanoscale potential barriers and/or AlGaAs atomically thin barriers around QDs, which prevent photoelectron capture to QDs. Under concentrated radiation, the short circuit current increases proportionally to the concentration and the open circuit voltage shows the logarithmic increase. In the range up to hundred Suns, the contributions of QDs to the photocurrent are proportional to the light concentration. The ideality factors of 1.1–1.3 found from the V OC -Sun characteristics demonstrate effective suppression of recombination processes in barrier-separated QDs. The conversion efficiency shows the wide maximum in the range of 40–90 Suns and reaches 21.6%. Detailed analysis of I-V-Sun characteristics shows that at low intensities, the series resistance decreases inversely proportional to the concentration and, at ∼40 Suns, reaches the plateau determined mainly by the front contact resistance. Improvement of contact resistance would increase efficiency to above 24% at thousand Suns

  17. Beam-Forming Concentrating Solar Thermal Array Power Systems

    Science.gov (United States)

    Cwik, Thomas A. (Inventor); Dimotakis, Paul E. (Inventor); Hoppe, Daniel J. (Inventor)

    2016-01-01

    The present invention relates to concentrating solar-power systems and, more particularly, beam-forming concentrating solar thermal array power systems. A solar thermal array power system is provided, including a plurality of solar concentrators arranged in pods. Each solar concentrator includes a solar collector, one or more beam-forming elements, and one or more beam-steering elements. The solar collector is dimensioned to collect and divert incoming rays of sunlight. The beam-forming elements intercept the diverted rays of sunlight, and are shaped to concentrate the rays of sunlight into a beam. The steering elements are shaped, dimensioned, positioned, and/or oriented to deflect the beam toward a beam output path. The beams from the concentrators are converted to heat at a receiver, and the heat may be temporarily stored or directly used to generate electricity.

  18. Long-term performance potential of concentrated photovoltaic (CPV) systems

    KAUST Repository

    Burhan, Muhammad

    2017-07-17

    Owing to the diverse photovoltaic (PV) systems’ design and technology, as well as the dynamic nature of insolation data received on the aperture surfaces, the instantaneous output from a PV system fluctuates greatly. For accurate performance estimation of a large PV field, the long term performance as electrical output is a more rational approach over the conventional testing methods, such as at Standard Testing Conditions (STC) and at the Nominal Operating Cell Temperature (NOCT) available hitherto. In this paper, the long-term performances of concentrated PVs (Cassegrain reflectors and Fresnel lens) with 2-axes tracking and a variety of PV systems, namely the stationary flat-plate PV (mono-crystalline, poly-crystalline and thin-films CIS types), is presented over a period of one year for the merit comparison of system design, under the tropical weather conditions of Singapore. From the measured field performances, the total energy output of 240.2 kW h/m/year is recorded for CPV operation in Singapore, which is nearly two folds higher than the stationary PV panels.

  19. Fuel cell system with interconnect

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Zhien; Goettler, Richard

    2016-12-20

    The present invention includes an integrated planar, series connected fuel cell system having electrochemical cells electrically connected via interconnects, wherein the anodes of the electrochemical cells are protected against Ni loss and migration via an engineered porous anode barrier layer.

  20. Ascorbate concentrations in vitro and in vivo, and their role in the radiation response of cells

    International Nuclear Information System (INIS)

    Stratford, M.R.L.; Hodgkiss, R.J.

    1985-01-01

    Hydrogen-atom or electron-transfer reactions of ascorbate are often invoked in discussing its potential role in radiobiology and free radical damage by cytotoxins, but detailed information on actual levels in experimental systems is lacking. A range of 0-250 μM ascorbate is present in several commonly used mammalian cell culture media. V79 379A Chinese hamster cells can concentrate ascorbate from medium containing 200 or 500 μM ascorbate but when ascorbate is absent in medium, cells do not appear to contain a significant amount. Tumour concentrations are approximately 1mM, similar to that of glutathione (GSH). There is much current interest in depleting cells of GSH to enhance radiosensitivity, and ascorbate is maintained by a GSH dependent enzyme, glutathione dehydrogenase. Data is presented on the effect of GSH depletion by buthionine sulphoximine on cell and tumour ascorbate levels, and the effect of ascorbate on in vitro radiosensitivity, and misonidazole sensitizing efficiency

  1. Parametric analysis of a hybrid solar concentrating photovoltaic/concentrating solar power (CPV/CSP) system

    International Nuclear Information System (INIS)

    Han, Xue; Zhao, Guankun; Xu, Chao; Ju, Xing; Du, Xiaoze; Yang, Yongping

    2017-01-01

    Highlights: • Performance of the hybrid system is evaluated with the energy and exergy analyses. • Trapezoidal-shaped distribution of concentrated radiation flux density is adopted. • Effects of the influencing factors are investigated to optimize the design parameters. • Performance and reliability of the system with various DNIs are also discussed. - Abstract: This paper presents a parametric study of a recently proposed concentrating photovoltaic/concentrating solar power (CPV/CSP) hybrid system based on the energy and exergy analyses. A steady-state physical model is established for the hybrid system to carry out the energy and exergy analyses, in which a more general trapezoidal-shaped distribution of concentrated solar energy flux density is employed. Effects of various parameters are investigated including the average optical concentration ratio, the outlet temperature of R134a from the solar thermal receiver, and the coolant saturation vapor temperature. The results show that the generating efficiency and the power output of the hybrid system can increase by about 20% compared with the CPV-alone system, which indicates that the proposed hybrid system has a great potential to increase the utilization ratio of solar energy. Increasing the average optical concentration ratio or decreasing the outlet temperature of R134a from the solar thermal receiver can result in evident increases of both the energy efficiency and the exergy efficiency of the hybrid system. It is also shown that the energy and exergy efficiencies of the organic Rankine cycle (ORC) subsystem are nearly independent of the Direct Normal Irradiance (DNI), and the hybrid system can be always operated with a high efficiency despite of the DNI change at different moments or days.

  2. Electrorefining cell with parallel electrode/concentric cylinder cathode

    Science.gov (United States)

    Gay, Eddie C.; Miller, William E.; Laidler, James J.

    1997-01-01

    A cathode-anode arrangement for use in an electrolytic cell is adapted for electrochemically refining spent nuclear fuel from a nuclear reactor and recovering purified uranium for further treatment and possible recycling as a fresh blanket or core fuel in a nuclear reactor. The arrangement includes a plurality of inner anodic dissolution baskets that are each attached to a respective support rod, are submerged in a molten lithium halide salt, and are rotationally displaced. An inner hollow cylindrical-shaped cathode is concentrically disposed about the inner anodic dissolution baskets. Concentrically disposed about the inner cathode in a spaced manner are a plurality of outer anodic dissolution baskets, while an outer hollow cylindrical-shaped is disposed about the outer anodic dissolution baskets. Uranium is transported from the anode baskets and deposited in a uniform cylindrical shape on the inner and outer cathode cylinders by rotating the anode baskets within the molten lithium halide salt. Scrapers located on each anode basket abrade and remove the spent fuel deposits on the surfaces of the inner and outer cathode cylinders, with the spent fuel falling to the bottom of the cell for removal. Cell resistance is reduced and uranium deposition rate enhanced by increasing the electrode area and reducing the anode-cathode spacing. Collection efficiency is enhanced by trapping and recovery of uranium dendrites scrapped off of the cylindrical cathodes which may be greater in number than two.

  3. AlGaInP/GaAs Tandem Solar Cells for Power Conversion at 400 degrees C and High Concentration

    Energy Technology Data Exchange (ETDEWEB)

    Steiner, Myles A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Perl, Emmett [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Simon, John D [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Friedman, Daniel J [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Jain, Nikhil [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Sharps, Paul [SolAero Technologies Corp.; McPheeters, Claiborne [SolAero Technologies Corp.; Lee, Minjoo L. [University of Illinois at Urbana-Champaign

    2017-09-06

    We demonstrate dual junction (Al)GaInP/GaAs solar cells that are designed to operate at 400 degrees C and 1000X concentration in a hybrid photovoltaic-solar thermal concentrator system. The cells have a front metallization and anti-reflection coating that are stable under 400 degrees C operation. We show how the cell performance degrades with increasing aluminum compositions in the top cell. Our best cell is a GaInP/GaAs tandem that demonstrated 15+/-1% efficiency at 400 degrees C over a concentration range of 300-1000 suns, with several pathways to improved performance.

  4. Does the intracellular ionic concentration or the cell water content (cell volume) determine the activity of TonEBP in NIH3T3 cells?

    DEFF Research Database (Denmark)

    Rødgaard, Tina; Schou, Kenneth; Friis, Martin Barfred

    2008-01-01

    of the present investigation was to investigate whether cell shrinkage or high intracellular ionic concentration induced the activation of TonEBP. We designed a model system for isotonically shrinking cells over a prolonged period of time. Cells swelled in hypotonic medium and performed a regulatory volume......Cl(-) co-transporter, and Gadolinium inhibited shrinkage-activated Na(+) channels. Cells remained shrunken for at least 4 hours (isotonically shrunken cells). The activity of TonEBP was investigated with a Luciferase assay after isotonic shrinkage and after shrinkage in a high NaCl hypertonic medium....... We found that TonEBP was strongly activated after 4 and 16 hours in cells in high NaCl hypertonic medium but not after 4 or 16 hours in isotonically shrunken cells. Cells treated with high NaCl hypertonic medium for 4 hours had significantly higher intracellular concentrations of both K(+) and Na...

  5. Performance investigation of a concentrating photovoltaic/thermal system with transmissive Fresnel solar concentrator

    International Nuclear Information System (INIS)

    Feng, Chaoqing; Zheng, Hongfei; Wang, Rui; Ma, Xinglong

    2016-01-01

    Highlights: • A common design method of a cycloidal transmissive Fresnel solar concentrator was presented. • The gallium arsenide high concentrated solar was used as the receiver. • High efficiency of electric generating could be achieved at noon. • Fresnel solar concentrator was studied and compared in hazy weather and clear weather. - Abstract: A design method of a cycloidal transmissive Fresnel solar concentrator which can provide a certain width focal line was presented in this study. Based on the optical principle of refraction, the dimensions of each wedge-shaped element of Fresnel lens are calculated. An optical simulation has been done to obtain the optical efficiency of the concentrator for different tracking error and axial incidence angle. It has been found that about 80% of the incident sunlight can still be gathered by the absorber when the tracking error is within 0.7°. When the axial angle of incidence is within 10°, it almost has no influence to the receiving rate. The concentrating photovoltaic/thermal system with transmissive Fresnel solar concentrator has been designed in this paper. Take the gallium arsenide high concentrated battery as the receiver, experimental research about cylindrical Fresnel concentrating photovoltaic/thermal system is undertaken in the real sky. Main parameters are tested such as the temperature distribution on receiver, electric energy and thermal energy outputs of concentrating photovoltaic/thermal system, the efficiency of multipurpose utilization of electric and heat, and so on. The test results in clear weather show that maximum electric generating efficiency is about 18% at noon, the maximum heat receiving rate of cooling water is about 45%. At noon time (11:00–13:00), the total efficiency of thermal and electricity can reach more than 55%. Performance of this concentrating photovoltaic/thermal system with transmissive Fresnel solar concentrator is studied and compared in two types typical weather, hazy

  6. Design and simulation of a low concentrating photovoltaic/thermal system

    International Nuclear Information System (INIS)

    Rosell, J.I.; Vallverdu, X.; Lechon, M.A.; Ibanez, M.

    2005-01-01

    The advantages of photovoltaic/thermal (PV/T) collectors and low solar concentration technologies are combined into a photovoltaic/thermal system to increase the solar energy conversion efficiency. This paper presents a prototype 11X concentration rate and two axis tracking system. The main novelty is the coupling of a linear Fresnel concentrator with a channel photovoltaic/thermal collector. An analytical model to simulate the thermal behaviour of the prototype is proposed and validated. Measured thermal performance of the solar system gives values above 60%. Theoretical analysis confirms that thermal conduction between the PV cells and the absorber plate is a critical parameter

  7. Elevated Concentrations of Serum Immunoglobulin Free Light Chains in Systemic Lupus Erythematosus Patients in Relation to Disease Activity, Inflammatory Status, B Cell Activity and Epstein-Barr Virus Antibodies

    DEFF Research Database (Denmark)

    Draborg, Anette H; Lydolph, Magnus; Westergaard, Marie

    2015-01-01

    , FLCs' association with Epstein-Barr virus (EBV) antibodies was examined. METHODS: Using a nephelometric assay, κFLC and λFLC concentrations were quantified in sera from 45 SLE patients and 40 healthy controls. SLE patients with renal insufficiency were excluded in order to preclude high concentrations...... of serum FLCs due to decreased clearance. RESULTS: Serum FLC concentrations were significantly elevated in SLE patients compared to healthy controls (pdisease activity (SLE disease activity......OBJECTIVE: In this study, we examined the concentration of serum immunoglobulin free light chains (FLCs) in systemic lupus erythematosus (SLE) patients and investigated its association with various disease parameters in order to evaluate the role of FLCs as a potential biomarker in SLE. Furthermore...

  8. Optical characterization of nonimaging dish concentrator for the application of dense-array concentrator photovoltaic system.

    Science.gov (United States)

    Tan, Ming-Hui; Chong, Kok-Keong; Wong, Chee-Woon

    2014-01-20

    Optimization of the design of a nonimaging dish concentrator (NIDC) for a dense-array concentrator photovoltaic system is presented. A new algorithm has been developed to determine configuration of facet mirrors in a NIDC. Analytical formulas were derived to analyze the optical performance of a NIDC and then compared with a simulated result obtained from a numerical method. Comprehensive analysis of optical performance via analytical method has been carried out based on facet dimension and focal distance of the concentrator with a total reflective area of 120 m2. The result shows that a facet dimension of 49.8 cm, focal distance of 8 m, and solar concentration ratio of 411.8 suns is the most optimized design for the lowest cost-per-output power, which is US$1.93 per watt.

  9. Counter-flow elutriation of clinical peripheral blood mononuclear cell concentrates for the production of dendritic and T cell therapies.

    Science.gov (United States)

    Stroncek, David F; Fellowes, Vicki; Pham, Chauha; Khuu, Hanh; Fowler, Daniel H; Wood, Lauren V; Sabatino, Marianna

    2014-09-17

    Peripheral blood mononuclear cells (PBMC) concentrates collected by apheresis are frequently used as starting material for cellular therapies, but the cell of interest must often be isolated prior to initiating manufacturing. The results of enriching 59 clinical PBMC concentrates for monocytes or lymphocytes from patients with solid tumors or multiple myeloma using a commercial closed system semi-automated counter-flow elutriation instrument (Elutra, Terumo BCT) were evaluated for quality and consistency. Elutriated monocytes (n = 35) were used to manufacture autologous dendritic cells and elutriated lymphocytes (n = 24) were used manufacture autologous T cell therapies. Elutriated monocytes with >10% neutrophils were subjected to density gradient sedimentation to reduce neutrophil contamination and elutriated lymphocytes to RBC lysis. Elutriation separated the PBMC concentrates into 5 fractions. Almost all of the lymphocytes, platelets and red cells were found in fractions 1 and 2; in contrast, most of the monocytes, 88.6 ± 43.0%, and neutrophils, 74.8 ± 64.3%, were in fraction 5. In addition, elutriation of 6 PBMCs resulted in relatively large quantities of monocytes in fractions 1 or 2. These 6 PBMCs contained greater quantities of monocytes than the other 53 PBMCs. Among fraction 5 isolates 38 of 59 contained >10% neutrophils. High neutrophil content of fraction 5 was associated with greater quantities of neutrophils in the PBMC concentrate. Following density gradient separation the neutrophil counts fell to 3.6 ± 3.4% (all products contained <10% neutrophils). Following red cell lysis of the elutriated lymphocyte fraction the lymphocyte recovery was 86.7 ± 24.0% and 34.3 ± 37.4% of red blood cells remained. Elutriation was consistent and effective for isolating monocytes and lymphocytes from PBMC concentrates for manufacturing clinical cell therapies, but further processing is often required.

  10. Hybrid photovoltaic-thermoelectric system for concentrated solar energy conversion: Experimental realization and modeling

    Science.gov (United States)

    Beeri, Ofer; Rotem, Oded; Hazan, Eden; Katz, Eugene A.; Braun, Avi; Gelbstein, Yaniv

    2015-09-01

    An experimental demonstration of the combined photovoltaic (PV) and thermoelectric conversion of concentrated sunlight (with concentration factor, X, up to ˜300) into electricity is presented. The hybrid system is based on a multi-junction PV cell and a thermoelectric generator (TEG). The latter increases the electric power of the system and dissipates some of the excessive heat. For X ≤ 200, the system's maximal efficiency, ˜32%, was mostly due to the contribution from the PV cell. With increasing X and system temperature, the PV cell's efficiency decreased while that of the TEG increased. Accordingly, the direct electrical contribution of the TEG started to dominate in the total system power, reaching ˜20% at X ≈ 290. Using a simple steady state finite element modeling, the cooling effect of the TEG on the hybrid system's efficiency was proved to be even more significant than its direct electrical contribution for high solar concentrations. As a result, the total efficiency contribution of the TEG reached ˜40% at X ≈ 200. This suggests a new system optimization concept that takes into account the PV cell's temperature dependence and the trade-off between the direct electrical generation and cooling capabilities of the TEG. It is shown that the hybrid system has a real potential to exceed 50% total efficiency by using more advanced PV cells and TE materials.

  11. An ambient radioxenon monitoring system based on fluid transfer concentration

    Science.gov (United States)

    Russ, William Robert, II

    A monitoring system using fluid transfer concentration has been developed to measure ambient radioxenon, an indicator of underground nuclear weapons testing. The monitoring system consists of a concentration system and detection system. Low concentrations of ambient radioxenon necessitate concentrating atmospheric xenon to enable detection of signature xenon radiation against normal background radiation. The concentration system relies on the preferential absorption of xenon in oil followed by the degassing of the fluid to produce an output containing a much greater fraction of xenon than the atmospheric input. The concentration system first absorbs ambient radioxenon then releases the radioxenon by degassing. A prototype packed bed absorption column was characterized. Columns of different dimensions and flow rates were modeled. Heating, ultrasound, bubbling, drawing a vacuum on the headspace above the oil and combinations thereof were evaluated as a means of degassing. An effective degassing technique was the combination of strong vacuum, cavitating agitation, and a packed bed. Various detectors and pulse processing techniques were evaluated. A combination of an electron detector and a photon detector was used to take advantage of the characteristic electron/photon coincidence radiation of radioxenon. A NaI(TI) scintillator was used as the photon detector, and a gas proportional detector, plastic scintillator and liquid scintillator were evaluated for use as the electron detector. Simple coincidence, coincidence with electron detector pulse height discrimination, coincidence with electron detector pulse shape discrimination, and delayed coincidence pulse processing techniques were evaluated as a means of minimizing background counts, especially from radon and radon progeny. The most promising detection systems were a gas proportional/NaI(TI) detector operated in coincidence mode using pulse height discrimination with the gas proportional detector, and a plastic

  12. Animal Cell Expression Systems.

    Science.gov (United States)

    Butler, M; Reichl, U

    2017-10-03

    control. Over the past decade, however, there have been various commercial influenza vaccines made available from cell technology using animal host cells. Analysis of glycosylation control shows that the type of host cell has the greatest influence on the final analyzed glycan profile. Other factors such as the virus strain, the cultivation system, or various process parameters have been shown to have only a minor effect on the glycosylation pattern. We predict that the analysis of glycan profiles in viral vaccines will become increasingly important in the development and consistent manufacturing of safe and potent vaccines. Graphical Abstract.

  13. Elevated CO2 concentration impacts cell wall polysaccharide composition of green microalgae of the genus Chlorella.

    Science.gov (United States)

    Cheng, Y-S; Labavitch, J M; VanderGheynst, J S

    2015-01-01

    The effect of CO2 concentration on the relative content of starch, lipid and cell wall carbohydrates in microalgal biomass was investigated for the four following Chlorella strains: C. vulgaris (UTEX 259), C. sorokiniana (UTEX 2805), C. minutissima (UTEX 2341) and C. variabilis (NC64A). Each strain had a different response to CO2 concentration. The starch content was higher in UTEX259 and NC64A cultured with 2% CO2 in the air supply than in cells cultured with ca. 0·04% CO2 (ambient air), while starch content was not affected for UTEX 2805 and UTEX 2341. The lipid content was higher in Chlorella minutissima UTEX 2341 cultured in 2% CO2 than in cells cultured in ambient air, but was unchanged for the other three strains. All four Chlorella strains tended to have a higher percentage of uronic acids and lower percentage of neutral sugars in their cell wall polysaccharide complement when grown with 2% CO2 supply. Although the percentage of neutral sugars in the cell walls varied with CO2 concentration, the relative proportions of different neutral sugar constituents remained constant for both CO2 conditions. The results demonstrate the importance of considering the effects of CO2 on the cell wall carbohydrate composition of microalgae. Microalgae have the potential to produce products that will reduce society's reliance on fossil fuels and address challenges related to food and feed production. An overlooked yet industrially relevant component of microalgae are their cell walls. Cell wall composition affects cell flocculation and the recovery of intracellular products. In this study, we show that increasing CO2 level results in greater cell wall polysaccharide and uronic acid content in the cell walls of three strains of microalgae. The results have implications on the management of systems for the capture of CO2 and production of fuels, chemicals and food from microalgae. © 2014 The Society for Applied Microbiology.

  14. Building a Six-Junction Inverted Metamorphic Concentrator Solar Cell

    Energy Technology Data Exchange (ETDEWEB)

    Geisz, John F [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Steiner, Myles A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Jain, Nikhil [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Schulte, Kevin L [National Renewable Energy Laboratory (NREL), Golden, CO (United States); France, Ryan M [National Renewable Energy Laboratory (NREL), Golden, CO (United States); McMahon, William E [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Perl, Emmett [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Friedman, Daniel J [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-12-02

    We propose practical six-junction (6J) inverted metamorphic multijunction (IMM) concentrator solar cell designs with the potential to exceed 50% efficiency using moderately high quality junction materials. We demonstrate the top three junctions and their monolithic integration lattice matched to GaAs using 2.1-eV AlGaInP, 1.7-eV AlGaAs or GaInAsP, and 1.4-eV GaAs with external radiative efficiencies >0.1%. We demonstrate tunnel junctions with peak tunneling current >400 A/cm2 that are transparent to <2.1-eV light. We compare the bottom three GaInAs(p) junctions with bandgaps of 1.2, 1.0, and 0.7 eV grown on InP and transparent metamorphic grades with low dislocation densities. The solution to an integration challenge resulting from Zn diffusion in the GaAs junction is illustrated in a five-junction IMM. Excellent 1-sun performance is demonstrated in a complete 6J IMM device with VOC = 5.15 V, and a promising pathway toward >50% efficiency at high concentrations is presented.

  15. Design and experimental investigation of a Multi-segment plate concentrated photovoltaic solar energy system

    International Nuclear Information System (INIS)

    Wang, Gang; Chen, Zeshao; Hu, Peng

    2017-01-01

    Highlights: • A multi-segment plate concentrated photovoltaic solar energy system was proposed. • A prototype of this new concentrator was developed for experimental investigation. • Experimental investigation results showed a good concentrating uniformity. - Abstract: Solar energy is one of the most promising renewable energies and meaningful for the sustainable development of energy source. A multi-segment plate concentrated photovoltaic (CPV) solar power system was proposed in this paper, the design principle of the multi-segment plate concentrator of this solar power system was given, which could provide uniform solar radiation flux density distribution on solar cells. A prototype of this multi-segment plate CPV solar power system was developed for the experimental study, aiming at the investigations of solar radiation flux density distribution and PV performances under this concentrator design. The experimental results showed that the solar radiation flux density distribution provided by the multi-segment plate concentrator had a good uniformity, and the number and temperature of solar cells both influence the photoelectric transformation efficiency of the CPV solar power system.

  16. Fuel cell system with interconnect

    Energy Technology Data Exchange (ETDEWEB)

    Goettler, Richard; Liu, Zhien

    2017-12-12

    The present invention includes a fuel cell system having a plurality of adjacent electrochemical cells formed of an anode layer, a cathode layer spaced apart from the anode layer, and an electrolyte layer disposed between the anode layer and the cathode layer. The fuel cell system also includes at least one interconnect, the interconnect being structured to conduct free electrons between adjacent electrochemical cells. Each interconnect includes a primary conductor embedded within the electrolyte layer and structured to conduct the free electrons.

  17. Experimental and theoretical model of a concentrating photovoltaic and thermal system

    International Nuclear Information System (INIS)

    Renno, C.; Petito, F.

    2016-01-01

    Highlights: • Experimental analysis of a concentrating photovoltaic system. • MJ cell electrical characterization and concentration factor evaluation. • Thermal model in ANSYS of the CPV/T system cooling circuit. - Abstract: The experimental and theoretical analysis of a concentrating photovoltaic and thermal system (CPV/T) presented in this paper allows to evaluate the electrical parameters of the system, the concentration factor, the cell temperature in different working conditions and the fluid temperature. In particular, the experimental values of the cell temperature represent the input of a model developed in ANSYS-CFX. This model evaluates the theoretical temperature values of the fluid that flows into the cooling circuit of the CPV/T system, designed with the CATIA software. Hence, both electrical and thermal parameters have been analyzed in order to evaluate the potential energy production of a concentrating photovoltaic and thermal system. Different configurations of the CPV/T system have been analyzed and the value of the concentration factor has been determined by means of an experimental procedure. The experimental and theoretical electric powers are compared in different climatic conditions considering a solar radiation included between 500 and 900 W/m 2 . The electric efficiency is also evaluated as function of solar irradiance and cloudiness. Moreover, the fluid temperature as function of the experimental cell temperature is determined in different working conditions by means of the ANSYS model. The fluid temperature is also theoretically determined varying the operating conditions along the circuit. Finally, a study of the electrical and thermal performances represents a key-factor to develop a more complex prototype of a CPV/T system.

  18. Limits to anaerobic energy and cytosolic concentration in the living cell

    Science.gov (United States)

    Paglietti, A.

    2015-11-01

    For many physical systems at any given temperature, the set of all states where the system's free energy reaches its largest value can be determined from the system's constitutive equations of internal energy and entropy, once a state of that set is known. Such an approach is fraught with complications when applied to a living cell, because the cell's cytosol contains thousands of solutes, and thus thousands of state variables, which makes determination of its state impractical. We show here that, when looking for the maximum energy that the cytosol can store and release, detailed information on cytosol composition is redundant. Compatibility with cell's life requires that a single variable that represents the overall concentration of cytosol solutes must fall between defined limits, which can be determined by dehydrating and overhydrating the cell to its maximum capacity. The same limits are shown to determine, in particular, the maximum amount of free energy that a cell can supply in fast anaerobic processes, starting from any given initial state. For a typical skeletal muscle in normal physiological conditions this energy, i.e., the maximum anaerobic capacity to do work, is calculated to be about 960 J per kg of muscular mass. Such energy decreases as the overall concentration of solutes in the cytosol is increased. Similar results apply to any kind of cell. They provide an essential tool to understand and control the macroscopic response of single cells and multicellular cellular tissues alike. The applications include sport physiology, cell aging, disease produced cell damage, drug absorption capacity, to mention the most obvious ones.

  19. Outdoor Performance Comparison of Concentrator Photovoltaic and Flat Plate Photovoltaic Systems

    OpenAIRE

    Hidaka Yoshihide; Imai Kenta; Ota Yasuyuki; Nishioka Kensuke

    2016-01-01

    Output characteristics of tracking type concentrator photovoltaic (CPV) system, multi-crystalline silicon (mc-Si) PV system, CIGS PV system, and amorphous silicon (a-Si) PV system were analyzed in the data period of a year from August 2013 to July 2014. In this study, we analyzed the influence of environmental factors using average photon energy (APE) and temperature of solar cell (Tcell). The characteristics of 14 kW CPV system, 50 kW mc-Si PV system, 60 kW CIGS PV system, 1.35 kW a-Si PV sy...

  20. Systems biomechanics of the cell

    CERN Document Server

    Maly, Ivan V

    2013-01-01

    Systems Biomechanics of the Cell attempts to outline systems biomechanics of the cell as an emergent and promising discipline. The new field owes conceptually to cell mechanics, organism-level systems biomechanics, and biology of biochemical systems. Its distinct methodology is to elucidate the structure and behavior of the cell by analyzing the unintuitive collective effects of elementary physical forces that interact within the heritable cellular framework. The problematics amenable to this approach includes the variety of cellular activities that involve the form and movement of the cell body and boundary (nucleus, centrosome, microtubules, cortex, and membrane). Among the elementary system effects in the biomechanics of the cell, instability of symmetry, emergent irreversibility, and multiperiodic dissipative motion can be noted. Research results from recent journal articles are placed in this unifying framework. It is suggested that the emergent discipline has the potential to expand the spectrum of ques...

  1. Construction and testing of a test stand for solar cells and concentrating collectors

    Science.gov (United States)

    Pfeiffer, H.

    1981-11-01

    A hibrid system consisting of photovoltaic cells and parabolic concentrators was built and tested in order to study the possible cost reduction of photovoltaic systems by concentration of sunlight. The test stand comprises four parabolic tracking reflectors, a cooling circuit, electrical and thermodynamical instrumentation and an electrical water pump as a load. The solar cells are mounted in the focal line of the collectors on a cooling channel designed for optimal heat transfer and their uniform illumination is carefully adjusted. The photovoltaic generator delivers electrical energy with 9.3% efficiency at 25 C. In the hybrid regime the thermal efficiency attains 45% at a temperature of 90 C, and the electrical efficiency 6%.

  2. Heat Transfer Phenomena in Concentrating Solar Power Systems.

    Energy Technology Data Exchange (ETDEWEB)

    Armijo, Kenneth Miguel; Shinde, Subhash L.

    2016-11-01

    Concentrating solar power (CSP) utilizes solar thermal energy to drive a thermal power cycle for the generation of electricity. CSP systems are facilitated as large, centralized power plants , such as power towers and trough systems, to take advantage of ec onomies of scale through dispatchable thermal energy storage, which is a principle advantage over other energy generation systems . Additionally, the combination of large solar concentration ratios with high solar conversion efficiencies provides a strong o pportunity of employment of specific power cycles such as the Brayton gas cycle that utilizes super critical fluids such as supercritical carbon dioxide (s CO 2 ) , compared to other sola r - fossil hybrid power plants. A comprehensive thermal - fluids examination is provided by this work of various heat transfer phenomena evident in CSP technologies. These include sub - systems and heat transfer fundamental phenomena evident within CSP systems , which include s receivers, heat transfer fluids (HTFs), thermal storage me dia and system designs , thermodynamic power block systems/components, as well as high - temperature materials. This work provides literature reviews, trade studies, and phenomenological comparisons of heat transfer media (HTM) and components and systems, all for promotion of high performance and efficient CSP systems. In addition, f urther investigations are also conducted that provide advanced heat transfer modeling approaches for gas - particle receiver systems , as well as performance/efficiency enhancement re commendations, particularly for solarized supercritical power systems .

  3. Influence of intracellular adenosine-triphosphate concentration of yeast cells on survival following X-irradiation

    International Nuclear Information System (INIS)

    Reinhard, R.D.; Pohlit, W.

    1975-01-01

    The effect of D-glucose, 2-deoxy-D-glucose and starvation in buffer on the ATP-concentration of yeast cells has been studied. In both the wild-type and a respiratory-deficient mutant strain 2-deoxy-D-glucose decreases the value for ATP, while it is enhanced by glucose only in the mutant strain. Populations with different ATP-concentrations have been irradiated. The results suggest that ATP may be an essential factor in the system that determines the length of the shoulder of the dose effect curves. (orig.) [de

  4. Concentration of carbon dioxide by a high-temperature electrochemical membrane cell

    Science.gov (United States)

    Kang, M. P.; Winnick, J.

    1985-01-01

    The performance of a molten carbonate carbon dioxide concentrator (MCCDC) cell, as a device for removal of CO2 from manned spacecraft cabins without fuel expenditure, is investigated. The test system consists of an electrochemical cell (with an Li2CO3-38 mol pct K2CO3 membrane contained in a LiAlO2 matrix), a furnace, and a flow IR analyzer for monitoring CO2. Operation of the MCCDC-driven cell was found to be suitable for the task of CO2 removal: the cell performed at extremely low CO2 partial pressures (at or above 0.1 mm Hg); cathode CO2 efficiencies of 97 percent were achieved with 0.25 CO2 inlet concentration at 19 mA sq cm, at temperatures near 873 K. Anode concentrations of up to 5.8 percent were obtained. Simple cathode and anode performance equations applied to correlate cell performance agreed well with those measured experimentally. A flow diagram for the process is included.

  5. Purifying, Separating, and Concentrating Cells From a Sample Low in Biomass

    Science.gov (United States)

    Benardini, James N.; LaDuc, Myron T.; Diamond, Rochelle

    2012-01-01

    Frequently there is an inability to process and analyze samples of low biomass due to limiting amounts of relevant biomaterial in the sample. Furthermore, molecular biological protocols geared towards increasing the density of recovered cells and biomolecules of interest, by their very nature, also concentrate unwanted inhibitory humic acids and other particulates that have an adversarial effect on downstream analysis. A novel and robust fluorescence-activated cell-sorting (FACS)-based technology has been developed for purifying (removing cells from sampling matrices), separating (based on size, density, morphology), and concentrating cells (spores, prokaryotic, eukaryotic) from a sample low in biomass. The technology capitalizes on fluorescent cell-sorting technologies to purify and concentrate bacterial cells from a low-biomass, high-volume sample. Over the past decade, cell-sorting detection systems have undergone enhancements and increased sensitivity, making bacterial cell sorting a feasible concept. Although there are many unknown limitations with regard to the applicability of this technology to environmental samples (smaller cells, few cells, mixed populations), dogmatic principles support the theoretical effectiveness of this technique upon thorough testing and proper optimization. Furthermore, the pilot study from which this report is based proved effective and demonstrated this technology capable of sorting and concentrating bacterial endospore and bacterial cells of varying size and morphology. Two commercial off-the-shelf bacterial counting kits were used to optimize a bacterial stain/dye FACS protocol. A LIVE/DEAD BacLight Viability and Counting Kit was used to distinguish between the live and dead cells. A Bacterial Counting Kit comprising SYTO BC (mixture of SYTO dyes) was employed as a broad-spectrum bacterial counting agent. Optimization using epifluorescence microscopy was performed with these two dye/stains. This refined protocol was further

  6. Functional Concentrations of BMP4 on Differentiation of Mouse Embryonic Stem Cells to Primordial Germ Cells

    Directory of Open Access Journals (Sweden)

    Hatef Ghasemi Hamidabadi

    2011-01-01

    Full Text Available Background: Bone morphogenetic protein 4 (BMP4 has a significant role in primordial germ cells(PGCs differentiation from mouse embryonic stem cell (mESC. The aim of this study is to determinethe best concentration of BMP4 at a time of two days on differentiation PGCs from mESC.Materials and Methods: To differentiate PGCs, embryoid bodies (EBs from mESCs were culturedin concentrations of 0, 5 and 10 ng/ml BMP4 for two days. Germ cell markers Oct4 (Pou5f1, Stella(Dppa3 and Mvh (Ddx4 were analyzed by flow cytometry, immunocytochemistry and reversetranscriptase polymerase chain reaction (RT-PCR.Results: Flow cytometry data demonstrated most Mvh-positive cells were observed only in thetreated groups. Immunocytochemistry of EBs in the treated groups identified cells positive forMvh. PCR results showed expression of Oct4 in the control group and treated groups. Stella andMvh were expressed only in the treated groups.Conclusion: Low concentrations of BMP4 during two days had an optimal effect on differentiationof PGCs from mESC.

  7. Flexible concentrator photovoltaics based on microscale silicon solar cells embedded in luminescent waveguides.

    Science.gov (United States)

    Yoon, Jongseung; Li, Lanfang; Semichaevsky, Andrey V; Ryu, Jae Ha; Johnson, Harley T; Nuzzo, Ralph G; Rogers, John A

    2011-06-14

    Unconventional methods to exploit monocrystalline silicon and other established materials in photovoltaic (PV) systems can create new engineering opportunities, device capabilities and cost structures. Here we show a type of composite luminescent concentrator PV system that embeds large scale, interconnected arrays of microscale silicon solar cells in thin matrix layers doped with luminophores. Photons that strike cells directly generate power in the usual manner; those incident on the matrix launch wavelength-downconverted photons that reflect and waveguide into the sides and bottom surfaces of the cells to increase further their power output, by more than 300% in examples reported here. Unlike conventional luminescent photovoltaics, this unusual design can be implemented in ultrathin, mechanically bendable formats. Detailed studies of design considerations and fabrication aspects for such devices, using both experimental and computational approaches, provide quantitative descriptions of the underlying materials science and optics.

  8. Flexible concentrator photovoltaics based on microscale silicon solar cells embedded in luminescent waveguides

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Jongseung [Univ. of Southern California, Los Angeles, CA (United States). Dept. of Chemical Engineering and Materials Science; Li, Lanfang [Univ. of Illinois, Urbana, IL (United States). Dept. of Materials Science and Engineering and Frederick Seitz Materials Research Lab. (FS-MRL); Semichaevsky, Andrey V. [Univ. of Illinois, Urbana, IL (United States). Dept. of Mechanical Science and Engineering; Ryu, Jae Ha [Univ. of Illinois, Urbana, IL (United States). Dept. of Materials Science and Engineering and Frederick Seitz Materials Research Lab. (FS-MRL); Johnson, Harley T. [Univ. of Illinois, Urbana, IL (United States). Dept. of Mechanical Science and Engineering and Frederick Seitz Materials Research Lab. (FS-MRL); Nuzzo, Ralph G. [Univ. of Illinois, Urbana, IL (United States). Dept. of Chemistry and Frederick Seitz Materials Research Lab. (FS-MRL); Rogers, John A. [Univ. of Illinois, Urbana, IL (United States). Depts. of Materials Science and Engineering, Mechanical Science and Engineering, Chemistry and Frederick Seitz Materials Research Lab. (FS-MRL)

    2011-06-14

    Unconventional methods to exploit monocrystalline silicon and other established materials in photovoltaic (PV) systems can create new engineering opportunities, device capabilities and cost structures. Here we show a type of composite luminescent concentrator PV system that embeds large scale, interconnected arrays of microscale silicon solar cells in thin matrix layers doped with luminophores. Photons that strike cells directly generate power in the usual manner; those incident on the matrix launch wavelength-downconverted photons that reflect and waveguide into the sides and bottom surfaces of the cells to increase further their power output, by more than 300% in examples reported here. Unlike conventional luminescent photovoltaics, this unusual design can be implemented in ultrathin, mechanically bendable formats. Detailed studies of design considerations and fabrication aspects for such devices, using both experimental and computational approaches, provide quantitative descriptions of the underlying materials science and optics.

  9. The effect of initial cell concentration on xylose fermentation by Pichia stipitis

    Science.gov (United States)

    Frank K. Agbogbo; Guillermo Coward-Kelly; Mads Torry-Smith; Kevin Wenger; Thomas W. Jeffries

    2007-01-01

    Xylose was fermented using Pichia stipitis CBS 6054 at different initial cell concentrations. A high initial cell concentration increased the rate of xylose utilization, ethanol formation, and the ethanol yield. The highest ethanol concentration of 41.0 g/L and a yield of 0.38 g/g was obtained using an initial cell concentration of 6.5 g/L. Even though more xylitol was...

  10. Effects of Nonuniform Incident Illumination on the Thermal Performance of a Concentrating Triple Junction Solar Cell

    Directory of Open Access Journals (Sweden)

    Fahad Al-Amri

    2014-01-01

    Full Text Available A numerical heat transfer model was developed to investigate the temperature of a triple junction solar cell and the thermal characteristics of the airflow in a channel behind the solar cell assembly using nonuniform incident illumination. The effects of nonuniformity parameters, emissivity of the two channel walls, and Reynolds number were studied. The maximum solar cell temperature sharply increased in the presence of nonuniform light profiles, causing a drastic reduction in overall efficiency. This resulted in two possible solutions for solar cells to operate in optimum efficiency level: (i adding new receiver plate with higher surface area or (ii using forced cooling techniques to reduce the solar cell temperature. Thus, surface radiation exchanges inside the duct and Re significantly reduced the maximum solar cell temperature, but a conventional plain channel cooling system was inefficient for cooling the solar cell at medium concentrations when the system was subjected to a nonuniform light distribution. Nonuniformity of the incident light and surface radiation in the duct had negligible effects on the collected thermal energy.

  11. Double red cell concentrates -in vitro quality after delayed refrigeration.

    Science.gov (United States)

    Thomas, S; Bekoe, Y; Uddin, S; Beard, M; Cardigan, R

    2010-10-01

    Automated collection of red cell concentrates (RCC) presents a number of potential advantages to donors, blood services and recipients, and allows the collection of finished components from sites that are remote from a blood centre. However, data are lacking on how long the collected RCC may be stored at ambient temperature prior to their final storage at 4 °C. In this study, the Haemonetics Cymbal device was used to collect RCC using citrate, phosphate and dextrose (CPD-50) anticoagulant. A total of 10 procedures each yielded two leucodepleted RCC in saline, adenine, glucose and mannitol (SAGM) additive solution. One of each pair of RCC was kept warm in an insulated transport bag for 8 h and the other for 6 h. In vitro assessments of the quality of the RCC were made during subsequent 42-day storage of the RCC at 2-6 °C, and compared with reference data. All collected RCC were within UK and European limits for volume, haematocrit and haemoglobin content. Haemolysis was within specification at Day 42 and was no different in RCC held warm for 6 or 8 hours, but tended to be higher than reference data from whole blood derived RCC. ATP, 2,3 DPG and supernatant potassium levels were all similar in RCC held warm for 6 or 8 hours and reference data. We conclude that the Cymbal device may be used to collect two RCC in SAGM, and the in vitro assessment indicates that RCC may be stored without refrigeration for up to 8 h following collection, prior to final storage at 4 °C. © 2010 The Authors. Transfusion Medicine © 2010 British Blood Transfusion Society.

  12. Performance enhancement of concentrated photovoltaic systems using a microchannel heat sink with nanofluids

    International Nuclear Information System (INIS)

    Radwan, Ali; Ahmed, Mahmoud; Ookawara, Shinichi

    2016-01-01

    Highlights: • A comprehensive model for the concentrated photovoltaic system is developed. • The Eulerian two-phase flow model is efficient to model nanofluids flow. • Higher solar cell efficiency is achieved by using Silicon Carbide–water nanofluids. • Microchannel cooling greatly reduces the cell temperature with less friction power. - Abstract: A new cooling technique for low concentrated photovoltaic–thermal (LCPV/T) systems is developed using a microchannel heat sink with nanofluids. In this study, Aluminum Oxide (Al 2 O 3 )–water and Silicon Carbide (SiC)–water nanofluids with different volume fractions are used as cooling mediums. The influence of cooling mass flow rate and nanoparticles volume fractions on the performance of LCPV/T system is investigated at different values of concentration ratio. A comprehensive model is developed which includes a thermal model for the photovoltaic layers, coupled with thermo-fluid dynamics of two-phase flow model of the microchannel heat sink. The model is numerically simulated to estimate the performance parameters such as the solar cell temperature and the electrical and thermal efficiency. Results indicate that a significant reduction in solar cell temperature is attained particularly at the high concentration ratio by using nanofluids compared to using water. Using SiC–water nanofluid achieves a relatively higher reduction in cell temperature than Al 2 O 3 –water nanofluid. By increasing the volume fraction of nanoparticles, both SiC–water and Al 2 O 3 –water nanofluids accomplish a major reduction of cell temperature. As a result, the use of nanofluids achieves higher solar cell electrical efficiency, particularly at lower Reynolds number (Re) and higher concentration ratio, than the use of water. The influence of nanofluids on thermal efficiency varies according to the concentration ratio. Furthermore, friction power increases with the increase in both Reynolds number and nanoparticle volume

  13. Experimental validation of a heat transfer model for concentrating photovoltaic system

    International Nuclear Information System (INIS)

    Sendhil Kumar, Natarajan; Matty, Katz; Rita, Ebner; Simon, Weingaertner; Ortrun, Aßländer; Alex, Cole; Roland, Wertz; Tim, Giesen; Tapas Kumar, Mallick

    2012-01-01

    In this paper, a three dimensional heat transfer model is presented for a novel concentrating photovoltaic design for Active Solar Panel Initiative System (ASPIS). The concentration ratio of two systems (early and integrated prototype) are 5× and 10× respectively, designed for roof-top integrated Photovoltaic systems. ANSYS 12.1, CFX package was effectively used to predict the temperatures of the components of the both ASPIS systems at various boundary conditions. The predicted component temperatures of an early prototype were compared with experimental results of ASPIS, which were carried out in Solecta – Israel and at the Austrian Institute of Technology (AIT) – Austria. It was observed that the solar cell and lens temperature prediction shows good agreement with Solecta measurements. The minimum and maximum deviation of 3.8% and 17.9% were observed between numerical and Solecta measurements and the maximum deviations of 16.9% were observed between modeling and AIT measurements. Thus, the developed validated thermal model enables to predict the component temperatures for concentrating photovoltaic systems. - Highlights: ► Experimentally validated heat transfer model for concentrating Photovoltaic system developed. ► Predictions of solar cell temperatures for parallactic tracking CPV system for roof integration. ► The ASPIS module contains 2 mm wide 216 solar cells manufactured based on SATURN technology. ► A solar cell temperature of 44 °C was predicted for solar radiation intensity was 1000 W/m 2 and ambient temperature was 20 °C. ► Average deviation was 6% and enabled to predict temperature of any CPV system.

  14. Biopsy needle advancement during bone marrow aspiration increases mesenchymal stem cell concentration

    Directory of Open Access Journals (Sweden)

    Anne E Peters

    2016-03-01

    Full Text Available Point-of-care kits to concentrate bone marrow (BM derived mesenchymal stem cells (MSCs are used clinically in horses. A maximal number of MSCs per ml of marrow aspirated might be desired prior to use of a point-of-care system to concentrate MSCs. Our objective was to test a method to increase the number of MSCs per ml of marrow collected. We collected 2 BM aspirates using 2 different collection techniques from 12 horses. The first collection technique was to aspirate BM from a single site without advancement of the biopsy needle. The second collection technique was to aspirate marrow from multiple sites within the same sternal puncture by advancing the needle 5 mm 3 times for BM aspiration from 4 sites. Numbers of MSCs in collected BM were assessed by total nucleated cell count (TNCC of BM after aspiration, total Colony-Forming-Unit-fibroblast (CFU-F assay, and total MSC number at each culture passage. The BM aspiration technique of 4 needle advancements during BM aspiration resulted in higher initial nucleated cell counts, more CFU-Fs, and more MSCs at the first passage. There were no differences in the number of MSCs at later passages. Multiple advancements of the BM needle during BM aspiration resulted in increased MSC concentration at the time of BM collection. If a point-of-care kit is used to concentrate MSCs, multiple advancements may result in higher MSC numbers in the BM concentrate after preparation by the point-of-care kit. For culture expanded MSCs beyond the first cell passage, the difference is of questionable clinical relevance.

  15. Maintaining molten salt electrolyte concentration in aluminum-producing electrolytic cell

    Energy Technology Data Exchange (ETDEWEB)

    Barnett, Robert J.; Mezner, Michael B.; Bradford, Donald R

    2005-01-04

    A method of maintaining molten salt concentration in a low temperature electrolytic cell used for production of aluminum from alumina dissolved in a molten salt electrolyte contained in a cell free of frozen crust wherein volatile material is vented from the cell and contacted and captured on alumina being added to the cell. The captured volatile material is returned with alumina to cell to maintain the concentration of the molten salt.

  16. V-trough concentrator on a photovoltaic full tracking system in a hot desert climate

    Energy Technology Data Exchange (ETDEWEB)

    Shaltout, M.A.M.; Ghettas, A.; Sabry, M. [National Research Inst., of Astronomy and Geophysics, Cairo (Egypt)

    1995-11-01

    A V-trough concentrator with a two-axis tracker system to increase the performance of photovoltaics was designed by the authors and installed on the roof-top of the building of the National Research Institute of Astronomy and Geophysics at Helwan in South Cairo. The V-trough concentrator system comprises two flat mirrors with dimensions 50 cm x 18 cm. They are fixed with the reflecting surfaces facing each other with a separation of about 11 cm, on a wooden table of 50 cm axis length. A sample of polycrystalline amorphous silicon cells were fixed into the system, and similar solar cells of each type were fixed separate to the system, to estimate the electrical gain. The measurements were performed daily at different air masses for one complete year. The temperature of the solar cells in and out of the system were measured for comparison. Also, measurements for beam and global solar radiation and other meteorological conditions were recorded. The optical losses of the system were analyzed and details of collectable energy calculations are presented. The energy gain from the isolated contribution of the V-trough concentrators is also evaluated. (Author)

  17. The volumes and transcript counts of single cells reveal concentration homeostasis and capture biological noise.

    NARCIS (Netherlands)

    Kempe, H.; Schwabe, A.; Crémazy, F.; Verschure, P.J.; Bruggeman, F.J.

    2015-01-01

    Transcriptional stochasticity can be measured by counting the number of mRNA molecules per cell. Cell-to-cell variability is best captured in terms of concentration rather than molecule counts, because reaction rates depend on concentrations. We combined single-molecule mRNA counting with

  18. A selective electrocatalyst-based direct methanol fuel cell operated at high concentrations of methanol.

    Science.gov (United States)

    Feng, Yan; Liu, Hui; Yang, Jun

    2017-06-01

    Owing to the serious crossover of methanol from the anode to the cathode through the polymer electrolyte membrane, direct methanol fuel cells (DMFCs) usually use dilute methanol solutions as fuel. However, the use of high-concentration methanol is highly demanded to improve the energy density of a DMFC system. Instead of the conventional strategies (for example, improving the fuel-feed system, membrane development, modification of electrode, and water management), we demonstrate the use of selective electrocatalysts to run a DMFC at high concentrations of methanol. In particular, at an operating temperature of 80°C, the as-fabricated DMFC with core-shell-shell Au@Ag 2 S@Pt nanocomposites at the anode and core-shell Au@Pd nanoparticles at the cathode produces a maximum power density of 89.7 mW cm -2 at a methanol feed concentration of 10 M and maintains good performance at a methanol concentration of up to 15 M. The high selectivity of the electrocatalysts achieved through structural construction accounts for the successful operation of the DMFC at high concentrations of methanol.

  19. A selective electrocatalyst–based direct methanol fuel cell operated at high concentrations of methanol

    Science.gov (United States)

    Feng, Yan; Liu, Hui; Yang, Jun

    2017-01-01

    Owing to the serious crossover of methanol from the anode to the cathode through the polymer electrolyte membrane, direct methanol fuel cells (DMFCs) usually use dilute methanol solutions as fuel. However, the use of high-concentration methanol is highly demanded to improve the energy density of a DMFC system. Instead of the conventional strategies (for example, improving the fuel-feed system, membrane development, modification of electrode, and water management), we demonstrate the use of selective electrocatalysts to run a DMFC at high concentrations of methanol. In particular, at an operating temperature of 80°C, the as-fabricated DMFC with core-shell-shell Au@Ag2S@Pt nanocomposites at the anode and core-shell Au@Pd nanoparticles at the cathode produces a maximum power density of 89.7 mW cm−2 at a methanol feed concentration of 10 M and maintains good performance at a methanol concentration of up to 15 M. The high selectivity of the electrocatalysts achieved through structural construction accounts for the successful operation of the DMFC at high concentrations of methanol. PMID:28695199

  20. Solar cooling with concentrating photovoltaic/thermal (CPVT) systems

    International Nuclear Information System (INIS)

    Mittelman, Gur; Kribus, Abraham; Dayan, Abraham

    2007-01-01

    Simultaneous production of electrical and high grade thermal energy is proposed with a concentrating photovoltaic/thermal (CPVT) system operating at elevated temperature. CPVT collectors may operate at temperatures above 100 o C, and the thermal energy can drive processes such as refrigeration, desalination and steam production. The performance and cost of a CPVT system with single effect absorption cooling are investigated in detail. The results show that under a wide range of economic conditions, the combined solar cooling and power generation plant can be comparable to, and sometimes even significantly better than, the conventional alternative

  1. Qualification and reliability of high-efficiency multi-junction concentrator solar cells for terrestrial applications

    Science.gov (United States)

    Hebert, Peter

    2008-08-01

    The concentrator photovoltaic (CPV) industry has created a qualification standard - IEC 62108. This standard applies to receivers and modules - certainly the most appropriate configurations for qualification and safety testing. CPV systems manufacturers expect the solar cells they buy to be qualified and highly reliable. However, the IEC qualification standard does not apply to the configurations offered by multijunction cell manufacturers and there are no accepted reliability test standards. This paper describes how one cell manufacturer adapted IEC 62108 to perform qualification testing on bare cells. Damp heat and high temperature durability qualification/reliability test results are shown for first generation CPV cells (C1MJ). Typical meteorological year data is analyzed for three locations to look at high temperature durability and to propose thermal cycle reliability test conditions. Space qualification testing is shown to envelope terrestrial thermal cycling and a thermal cycling reliability test is proposed. The space heritage of commercially available cells is reviewed to provide some background on reliability of multijunction cells.

  2. Concentrator Photovoltaics

    CERN Document Server

    Luque, Antonio L

    2007-01-01

    Photovoltaic solar-energy conversion is one of the most promising technologies for generating renewable energy, and conversion of concentrated sunlight can lead to reduced cost for solar electricity. In fact, photovoltaic conversion of concentrated sunlight insures an efficient and cost-effective sustainable power resource. This book gives an overview of all components, e.g. cells, concentrators, modules and systems, for systems of concentrator photovoltaics. The authors report on significant results related to design, technology, and applications, and also cover the fundamental physics and market considerations. Specific contributions include: theory and practice of sunlight concentrators; an overview of concentrator PV activities; a description of concentrator solar cells; design and technology of modules and systems; manufacturing aspects; and a market study.

  3. Hydrogen depolarized carbon dioxide concentrator performance improvements and cell pair structural tests. [for manned space station

    Science.gov (United States)

    Huddleston, J. D.; Aylward, J. R.

    1973-01-01

    The investigations and testing associated with the CO2 removal efficiency and voltage degradation of a hydrogen depolarized carbon oxide concentrator are reported. Also discussed is the vibration testing of a water vapor electrolysis cell pair. Performance testing of various HDC cell pairs with Cs2CO3 electrolyte provided sufficient parametric and endurance data to size a six man space station prototype CO2 removal system as having 36 HDC cell pairs, and to verify a life capability exceeding six moths. Testing also demonstrated that tetramethylammonium carbonate is an acceptable HDC electrolyte for operating over the relative humidity range of 30 to 90 percent and over a temperature range of 50 to 80 F.

  4. Particle Size Affects Concentration-Dependent Cytotoxicity of Chitosan Nanoparticles towards Mouse Hematopoietic Stem Cells

    Directory of Open Access Journals (Sweden)

    Siti Sarah Omar Zaki

    2015-01-01

    Full Text Available Chitosan nanoparticles (CSNPs have been extensively applied in medical and pharmaceutical fields as promising drug delivery systems. Despite that, the safety of CSNPs remains inadequate and needs further investigation, particularly on hematopoietic stem cells (HSCs. CSNPs were prepared by ionic gelation method and later were characterized for their physical characteristics (particle size and zeta potential. Cytotoxicity of CSNPs was assessed by MTT assay. Particle size was highly influenced by chitosan concentration and molecular weight (medium and high molecular weight (MMW and HMW. Higher chitosan concentration and molecular weight produced larger nanoparticles. Zeta potential of CSNPs was not significantly affected by chitosan concentrations and molecular weights used in the present study. MMW had a better stability than HMW CSNPs as their particle size and zeta potential were not significantly altered after autoclaving. Cytotoxicity of CSNPs was influenced by zeta potential and particle size. On the other hand, chitosan concentration and molecular weight indirectly influenced cytotoxicity by affecting particle size and zeta potential of CSNPs. In conclusion, cytotoxicity of CSNPs was mainly attributed to their physical characteristics and this opens a strategy to ensure the safety of CSNPs applications in stem cell technology.

  5. Particle Size Affects Concentration-Dependent Cytotoxicity of Chitosan Nanoparticles towards Mouse Hematopoietic Stem Cells

    International Nuclear Information System (INIS)

    Zaki, S. S. O.; Ibrahim, M. N.; Katas, H.

    2015-01-01

    Chitosan nanoparticles (CSNPs) have been extensively applied in medical and pharmaceutical fields as promising drug delivery systems. Despite that, the safety of CSNPs remains inadequate and needs further investigation, particularly on hematopoietic stem cells (HSCs). CSNPs were prepared by ionic gelation method and later were characterized for their physical characteristics (particle size and zeta potential). Cytotoxicity of CSNPs was assessed by MTT assay. Particle size was highly influenced by chitosan concentration and molecular weight (medium and high molecular weight (MMW and HMW)). Higher chitosan concentration and molecular weight produced larger nanoparticles. Zeta potential of CSNPs was not significantly affected by chitosan concentrations and molecular weights used in the present study. MMW had a better stability than HMW CSNPs as their particle size and zeta potential were not significantly altered after autoclaving. Cytotoxicity of CSNPs was influenced by zeta potential and particle size. On the other hand, chitosan concentration and molecular weight indirectly influenced cytotoxicity by affecting particle size and zeta potential of CSNPs. In conclusion, cytotoxicity of CSNPs was mainly attributed to their physical characteristics and this opens a strategy to ensure the safety of CSNPs applications in stem cell technology.

  6. Ozone concentration-monitoring photoacoustic system based on a frequency-quadrupled Nd:YAG laser

    Science.gov (United States)

    Ajtai, T.; Filep, Á.; Varga, A.; Motika, G.; Bozóki, Z.; Szabó, G.

    2010-10-01

    A novel type of system based on a frequency-quadrupled Nd:YAG laser light source at 266 nm and a dual-cell photoacoustic detection unit was developed, and its applicability for ozone-concentration measurement with a minimum detectable ozone concentration of about 100 pptV was demonstrated. The instrument was calibrated against an ozone generator, and it was installed at a regional environmental monitoring station to be operated in parallel with a commercial UV-absorption photometry based ozone-monitoring instrument. While good agreement between the readings of the two systems was found, the photoacoustic system outperformed its optical absorption based counterpart as far as minimum detectable concentration and measurement accuracy is concerned.

  7. The experimental study of a two-stage photovoltaic thermal system based on solar trough concentration

    International Nuclear Information System (INIS)

    Tan, Lijun; Ji, Xu; Li, Ming; Leng, Congbin; Luo, Xi; Li, Haili

    2014-01-01

    Highlights: • A two-stage photovoltaic thermal system based on solar trough concentration. • Maximum cell efficiency of 5.21% with the mirror opening width of 57 cm. • With single cycle, maximum temperatures rise in the heating stage is 12.06 °C. • With 30 min multiple cycles, working medium temperature 62.8 °C, increased 28.7 °C. - Abstract: A two-stage photovoltaic thermal system based on solar trough concentration is proposed, in which the metal cavity heating stage is added on the basis of the PV/T stage, and thermal energy with higher temperature is output while electric energy is output. With the 1.8 m 2 mirror PV/T system, the characteristic parameters of the space solar cell under non-concentrating solar radiation and concentrating solar radiation are respectively tested experimentally, and the solar cell output characteristics at different opening widths of concentrating mirror of the PV/T stage under condensation are also tested experimentally. When the mirror opening width was 57 cm, the solar cell efficiency reached maximum value of 5.21%. The experimental platform of the two-stage photovoltaic thermal system was established, with a 1.8 m 2 mirror PV/T stage and a 15 m 2 mirror heating stage, or a 1.8 m 2 mirror PV/T stage and a 30 m 2 mirror heating stage. The results showed that with single cycle, the long metal cavity heating stage would bring lower thermal efficiency, but temperature rise of the working medium is higher, up to 12.06 °C with only single cycle. With 30 min closed multiple cycles, the temperature of the working medium in the water tank was 62.8 °C, with an increase of 28.7 °C, and thermal energy with higher temperature could be output

  8. Ambient pressure fuel cell system

    Science.gov (United States)

    Wilson, Mahlon S.

    2000-01-01

    An ambient pressure fuel cell system is provided with a fuel cell stack formed from a plurality of fuel cells having membrane/electrode assemblies (MEAs) that are hydrated with liquid water and bipolar plates with anode and cathode sides for distributing hydrogen fuel gas and water to a first side of each one of the MEAs and air with reactant oxygen gas to a second side of each one of the MEAs. A pump supplies liquid water to the fuel cells. A recirculating system may be used to return unused hydrogen fuel gas to the stack. A near-ambient pressure blower blows air through the fuel cell stack in excess of reaction stoichiometric amounts to react with the hydrogen fuel gas.

  9. Concentrating PV/T Hybrid System for Simultaneous Electricity and Usable Heat Generation: A Review

    Directory of Open Access Journals (Sweden)

    Longzhou Zhang

    2012-01-01

    Full Text Available Photovoltaic (PV power generation is one of the attractive choices for efficient utilization of solar energy. Considering that the efficiency and cost of PV cells cannot be significantly improved in near future, a relatively cheap concentrator to replace part of the expensive solar cells could be used. The photovoltaic thermal hybrid system (PV/T, combining active cooling with thermal electricity and providing both electricity and usable heat, can enhance the total efficiency of the system with reduced cell area. The effect of nonuniform light distribution and the heat dissipation on the performance of concentrating PV/T was discussed. Total utilization of solar light by spectral beam splitting technology was also introduced. In the last part, we proposed an integrated compound parabolic collector (CPC plate with low precision solar tracking, ensuring effective collection of solar light with a significantly lowered cost. With the combination of beam splitting of solar spectrum, use of film solar cell, and active liquid cooling, efficient and full spectrum conversion of solar light to electricity and heat, in a low cost way, might be realized. The paper may offer a general guide to those who are interested in the development of low cost concentrating PV/T hybrid system.

  10. THE PROGRAMED CELL DEATH REGULATORS OF ISOLATED MODEL SYSTEMS

    Directory of Open Access Journals (Sweden)

    D. V. Vatlitsov

    2016-06-01

    Full Text Available The technology evolution creates the prerequisites for the emergence of new informational concept and approaches to the formation of a fundamentally new principles of biological objects understanding. The aim was to study the activators of the programmed cell death in an isolated system model. Cell culture aging parameters were performed on flow cytometer. It had formed the theory that the changes in the concentrations of metal ions and increase their extracellular concentration had formed a negative gradient into the cells.regulation of cell death. It was shown that the metals ions concentrations.

  11. Dynamic behavior of a multi-effect sugar concentrator system

    International Nuclear Information System (INIS)

    Aly, N.H.; Marwan, M.A.

    1994-01-01

    A transient mathematical model is developed to simulate the dynamic response of multi effect evaporator for sugar distiller concentrators at delta company, Egypt. Based on the mass and energy balance equations, a non linear mathematical model relating the system variables is obtained. This model allows to investigate the response of the unit parameters in both steady state and transient operating condition. Also, the response of the unit to perturbations in feed syrup, flow rate, concentration and heating steam temperature is studied. The predicted response based on the solution of the mathematical model is illustrated. The developed model proved to be efficient and capable to predict different operating conditions at steady state or transients variations. The study shows that an increase in heating steam temperature can be a critical factor due to caramelization of the syrup. 1 tab., 10 fig

  12. Remote information concentration and multipartite entanglement in multilevel systems

    Energy Technology Data Exchange (ETDEWEB)

    Wang Xinwen; Zhang Dengyu; Tang Shiqing; Xie Lijun [Department of Physics and Electronic Information, Hengyang Normal University, Hengyang 421008 (China); Yang Guojian [Department of Physics, Beijing Normal University, Beijing 100875 (China)

    2011-10-15

    Remote information concentration (RIC) in d-level systems (qudits) is studied. It is shown that the quantum information initially distributed in three spatially separated qudits can be remotely and deterministically concentrated to a single qudit via an entangled channel without performing any global operations. The entangled channel can be different types of genuine multipartite pure entangled states which are inequivalent under local operations and classical communication. The entangled channel can also be a mixed entangled state, even a bound entangled state which has a similar form to the Smolin state, but has different features from the Smolin state. A common feature of all these pure and mixed entangled states is found; i.e., they have d{sup 2} common commuting stabilizers. The differences of qudit-RIC and qubit-RIC (d=2) are also analyzed.

  13. Outdoor Performance Comparison of Concentrator Photovoltaic and Flat Plate Photovoltaic Systems

    Directory of Open Access Journals (Sweden)

    Hidaka Yoshihide

    2016-01-01

    Full Text Available Output characteristics of tracking type concentrator photovoltaic (CPV system, multi-crystalline silicon (mc-Si PV system, CIGS PV system, and amorphous silicon (a-Si PV system were analyzed in the data period of a year from August 2013 to July 2014. In this study, we analyzed the influence of environmental factors using average photon energy (APE and temperature of solar cell (Tcell. The characteristics of 14 kW CPV system, 50 kW mc-Si PV system, 60 kW CIGS PV system, 1.35 kW a-Si PV system were evaluated and compared. As a result, the output performance of CPV was highest between the four systems at the most frequent conditions in the outdoor environment.

  14. Design of a novel concentrating photovoltaic–thermoelectric system incorporated with phase change materials

    International Nuclear Information System (INIS)

    Cui, Tengfei; Xuan, Yimin; Li, Qiang

    2016-01-01

    Highlights: • A novel photovoltaic–thermoelectric system integrated with phase change materials is proposed. • The theoretical model of the PV–PCM–TE system is established to study its feasibility. • The PV–PCM–TE system is proved to be superior to single PV cells and PV–TE systems. • The influence parameters of the PV–PCM–TE system are investigated. - Abstract: Since the solar irradiance within a day is varying, the temperature of the photovoltaic–thermoelectric (PV–TE) system becomes fluctuant with the change of the incident solar irradiance, which exerts a significant influence on the efficiency of the total system. In this paper, the phase change material (PCM) is introduced into the PV–TE system to construct a novel PV–PCM–TE hybrid system. The purposes of applying PCM are to mitigate the temperature fluctuations of the PV cell and the TE modules and keep the hybrid PV–TE system operating under a fixed operating condition. A theoretical model of evaluating the efficiency of the concentrating PV–PCM–TE hybrid system is presented. The feasibility of the PV–PCM–TE system with four types of PV cells, c-Si, CIGS, single-junction GaAs, and GaInP/InGaAs/Ge (III–V), are investigated. The optimum operating conditions which indicate that the PV–PCM–TE system has the highest total efficiency are discussed to determine the melting temperatures of PCMs. A series of structure parameters are designed to obtain the optimized parameters for the PV–PCM–TE system, and the influences of these parameters on the PV–PCM–TE system are investigated. The results indicate that the performance of the PV–PCM–TE system is superior to single PV cells and/or PV–TE systems.

  15. A high-throughput AO/PI-based cell concentration and viability detection method using the Celigo image cytometry.

    Science.gov (United States)

    Chan, Leo Li-Ying; Smith, Tim; Kumph, Kendra A; Kuksin, Dmitry; Kessel, Sarah; Déry, Olivier; Cribbes, Scott; Lai, Ning; Qiu, Jean

    2016-10-01

    To ensure cell-based assays are performed properly, both cell concentration and viability have to be determined so that the data can be normalized to generate meaningful and comparable results. Cell-based assays performed in immuno-oncology, toxicology, or bioprocessing research often require measuring of multiple samples and conditions, thus the current automated cell counter that uses single disposable counting slides is not practical for high-throughput screening assays. In the recent years, a plate-based image cytometry system has been developed for high-throughput biomolecular screening assays. In this work, we demonstrate a high-throughput AO/PI-based cell concentration and viability method using the Celigo image cytometer. First, we validate the method by comparing directly to Cellometer automated cell counter. Next, cell concentration dynamic range, viability dynamic range, and consistency are determined. The high-throughput AO/PI method described here allows for 96-well to 384-well plate samples to be analyzed in less than 7 min, which greatly reduces the time required for the single sample-based automated cell counter. In addition, this method can improve the efficiency for high-throughput screening assays, where multiple cell counts and viability measurements are needed prior to performing assays such as flow cytometry, ELISA, or simply plating cells for cell culture.

  16. Trapping light escaping from the edges of the optical element in a Concentrating Photovoltaic system

    International Nuclear Information System (INIS)

    Baig, Hasan; Sellami, Nazmi; Mallick, Tapas K.

    2015-01-01

    Highlights: • Influence of encapsulant spillage on the optical performance. • Use of reflective film along the edge to trap light. • Optical performance improvement of a concentrating photovoltaic system. • Experimental validation of results. - Abstract: The encapsulant is an important element used for mechanical bonding and optical coupling between the concentrator and the solar cell in a typical concentrating photovoltaic system. In this work we explain the concept of trapping the light escaping through the optical concentrator – encapsulant interface. Understanding how the losses incur is important for the development of concentrating photovoltaic systems. A case study is performed on a 3D Cross Compound Parabolic Concentrator (3DCCPC) based low concentrating photovoltaic system. Detailed optical analysis is presented quantifying the losses based on the thickness of the encapsulant spillage. Simulation results show that the optical efficiency drops from 84.5% to 55.6% whilst increase in the encapsulant spillage thickness from 0.1 mm to 3 mm. Use of reflective film is made along the bottom edges of the concentrator in order to make the interface region optically inactive to carry out refraction and trap the escaping light. Modelling shows that the optical losses can be completely managed by the use of the reflective film. Experiments are carried out by building a prototype in order to demonstrate the concept and validate the results. The short circuit current is found to increase by a maximum of 8.5%. A maximum power ratio of 2.73 is observed at an incidence angle of 10° for the system using the reflective film compared to 2.56 without the reflective film

  17. PDMS/glass microfluidic cell culture system for cytotoxicity tests and cells passage

    DEFF Research Database (Denmark)

    Ziolkowska, K.; Jedrych, E.; Kwapiszewski, R.

    2010-01-01

    In this paper, hybrid (PDMS/glass) microfluidic cell culture system (MCCS) integrated with the concentration gradient generator (CGG) is presented. PDMS gas permeability enabled cells' respiration in the fabricated microdevices and excellent glass hydrophilicity allowed successful cells' seeding......' bioactivity, defining the lowest toxic level of tested substances etc....

  18. Performance optimization of dense-array concentrator photovoltaic system considering effects of circumsolar radiation and slope error.

    Science.gov (United States)

    Wong, Chee-Woon; Chong, Kok-Keong; Tan, Ming-Hui

    2015-07-27

    This paper presents an approach to optimize the electrical performance of dense-array concentrator photovoltaic system comprised of non-imaging dish concentrator by considering the circumsolar radiation and slope error effects. Based on the simulated flux distribution, a systematic methodology to optimize the layout configuration of solar cells interconnection circuit in dense array concentrator photovoltaic module has been proposed by minimizing the current mismatch caused by non-uniformity of concentrated sunlight. An optimized layout of interconnection solar cells circuit with minimum electrical power loss of 6.5% can be achieved by minimizing the effects of both circumsolar radiation and slope error.

  19. Analysis of a Concentrated Solar Thermophotovoltaic System with Thermal Energy Storage

    Science.gov (United States)

    Seyf, Hamid Reza; Henry, Asegun

    2017-01-01

    We analyzed a high temperature concentrated solar thermophotovoltaic (TPV) system with thermal energy storage (TES), which is enabled by the potential usage of liquid metal as a high temperature heat transfer fluid. The system concept combines the great advantages of TES with the potential for low cost and high performance derived from photovoltaic cells fabricated on reusable substrates, with a high reflectivity back reflector for photon recycling. The TES makes the electricity produced dispatchable, and thus the system studied should be compared to technologies such as concentrated solar power (CSP) with TES (e.g., using a turbine) or PV with electrochemical batteries, instead of direct and intermittent electricity generation from flat plate PV alone. Thus, the addition of TES places the system in a different class than has previously been considered and based on the model results, appears worthy of increased attention. The system level analysis presented identifies important cell level parameters that have the greatest impact on the overall system performance, and as a result can help to set the priorities for future TPV cell development.

  20. Optimum Design Of Grid Connected Photovoltaic System Using Concentrators

    Directory of Open Access Journals (Sweden)

    Eng. Mohammed Fawzy

    2015-08-01

    Full Text Available Abstract Due to the increasing demand of electrical energy in Egypt and also in many neighboring countries around the world the main problem facing electrical energy production using classical methods such steam power stations is the depletion of fossil fuels. The gap between the electrical energy demand and the continuous increase on the fossil fuel cost make the problem of electricity generation more sophisticated. With the continuous decrease of the photovoltaic PV technologies cost it doesnt make sense neglecting the importance of electricity production using solar photovoltaic PV especially that the annual average daily energy received is about 6 kamp12310whmamp123112day in Cairo Egypt 30N.In this work a detailed simulation model including photovoltaic PV module characteristics and climatic conditions of Cairo Egypt is developed. The model compares fixed PV systems electrical energy output with photovoltaic PV system using concentrators and double axis tracker systems. The comparison includes the energy generated area required as well as the cost per kwh generated. The optimality criterion is the cost per kwh generated. The system that gives the minimum cost per kwh is the optimum system. To verify the developed model the simulation results of fixed PV modules and CPV using tracking system obtained by the model are compared with practical measurements of 40KW peak station erected in Cairo Egypt 30N.Very good agreement between measured values and results obtained from detailed simulation model. For fixed PV system the detailed economic analysis showed that it gives minimum cost perkwh generated Comparisons among these systems are presented. For Cairo results showed that a cost of about 6 to 9 US centskwh is attainable.

  1. Reformate fuel cell system durability

    Energy Technology Data Exchange (ETDEWEB)

    Borup, R. L. (Rodney L.); Inbody, M. A. (Michael A.); Uribe, F. A. (Francisco A.); Tafoya, J. (Jose I.)

    2002-01-01

    The goal of this research is to identify the factors limiting the durability of fuel cells and fuel processors. This includes identifying PEM fuel cell durability issues for operating on pure hydrogen, and those that arise from the fuel processing of liquid hydrocarbons (e.g., gasoline) as a function of fuel composition and impurity content. Benchmark comparisons with the durability of fuel cells operating on pure hydrogen are used to identify limiting factors unique to fuel processing. We describe the design, operation and operational results of the durability system, including the operating conditions for the system, fuel processor sub-section operation over 1000 hours, post-mortem characterization of the catalysts in the fuel processor, and single cell operation.

  2. Standard Test Method for Electrical Performance of Concentrator Terrestrial Photovoltaic Modules and Systems Under Natural Sunlight

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2009-01-01

    1.1 This test method covers the determination of the electrical performance of photovoltaic concentrator modules and systems under natural sunlight using a normal incidence pyrheliometer. 1.2 The test method is limited to module assemblies and systems where the geometric concentration ratio specified by the manufacturer is greater than 5. 1.3 This test method applies to concentrators that use passive cooling where the cell temperature is related to the air temperature. 1.4 Measurements under a variety of conditions are allowed; results are reported under a select set of concentrator reporting conditions to facilitate comparison of results. 1.5 This test method applies only to concentrator terrestrial modules and systems. 1.6 This test method assumes that the module or system electrical performance characteristics do not change during the period of test. 1.7 The performance rating determined by this test method applies only at the period of the test, and implies no past or future performance level. 1.8...

  3. A sensor-less methanol concentration control system based on feedback from the stack temperature

    International Nuclear Information System (INIS)

    An, Myung-Gi; Mehmood, Asad; Ha, Heung Yong

    2014-01-01

    Highlights: • A new sensor-less methanol control algorithm based on feedback from the stack temperature is developed. • Feasibility of the algorithm is tested using a DMFC system with a recirculating fuel loop. • The algorithm precisely controls the methanol concentration without the use of methanol sensors. • The sensor-less controller shortens the time that the DMFC system requires to go from start-up to steady-state. • This controller is effective in handling unexpected changes in the methanol concentration and stack temperature. - Abstract: A sensor-less methanol concentration control system based on feedback from the stack temperature (SLCCF) has been developed. The SLCCF algorithm is embedded into an in-house LabVIEW program that has been developed to control the methanol concentration in the feed of direct methanol fuel cells (DMFCs). This control method utilizes the close correlation between the stack temperature and the methanol concentration in the feed. Basically, the amounts of methanol to be supplied to the re-circulating feed stream are determined by estimating the methanol consumption rates under given operating conditions, which are then adjusted by a proportional–integral controller and supplied into the feed stream to maintain the stack temperature at a set value. The algorithm is designed to control the methanol concentration and the stack temperature for both start-up and normal operation processes. Feasibility tests with a 200 W-class DMFC system under various operating conditions confirm that the algorithm successfully maintains the methanol concentration in the feed as well as the stack temperature at set values, and the start-up time required for the DMFC system to reach steady-state operating conditions is reduced significantly compared with conventional sensor-less methods

  4. Critical Filler Concentration in Sulfated Titania-Added Nafion™ Membranes for Fuel Cell Applications

    Directory of Open Access Journals (Sweden)

    Mirko Sgambetterra

    2016-04-01

    Full Text Available In this communication we present a detailed study of Nafion™ composite membranes containing different amounts of nanosized sulfated titania particles, synthesized through an optimized one-step synthesis procedure. Functional membrane properties, such as ionic exchange capacity and water uptake (WU ability will be described and discussed, together with thermal analysis, atomic force microscopy and Raman spectroscopy data. Also electrochemical properties such as proton conductivity and performances in hydrogen fuel cells will be presented. It has been demonstrated that a critical concentration of filler particles can boost the fuel cell performance at low humidification, exhibiting a significant improvement of the maximum power and current density delivered under 30% low-relative humidity (RH and 70 °C with respect to bare Nafion™-based systems.

  5. Experimental System of Solar Adsorption Refrigeration with Concentrated Collector.

    Science.gov (United States)

    Yuan, Z X; Li, Y X; Du, C X

    2017-10-18

    To improve the performance of solar adsorption refrigeration, an experimental system with a solar concentration collector was set up and investigated. The main components of the system were the adsorbent bed, the condenser, the evaporator, the cooling sub-system, and the solar collector. In the first step of the experiment, the vapor-saturated bed was heated by the solar radiation under closed conditions, which caused the bed temperature and pressure to increase. When the bed pressure became high enough, the bed was switched to connect to the condenser, thus water vapor flowed continually from the bed to the condenser to be liquefied. Next, the bed needed to cool down after the desorption. In the solar-shielded condition, achieved by aluminum foil, the circulating water loop was opened to the bed. With the water continually circulating in the bed, the stored heat in the bed was took out and the bed pressure decreased accordingly. When the bed pressure dropped below the saturation pressure at the evaporation temperature, the valve to the evaporator was opened. A mass of water vapor rushed into the bed and was adsorbed by the zeolite material. With the massive vaporization of the water in the evaporator, the refrigeration effect was generated finally. The experimental result has revealed that both the COP (coefficient of the performance of the system) and the SCP (specific cooling power of the system) of the SAPO-34 zeolite was greater than that of the ZSM-5 zeolite, no matter whether the adsorption time was longer or shorter. The system of the SAPO-34 zeolite generated a maximum COP of 0.169.

  6. Enhanced Vertical Concentration Gradient in Rubbed P3HT:PCBM Graded Bilayer Solar Cells.

    Science.gov (United States)

    Vohra, Varun; Arrighetti, Gianmichele; Barba, Luisa; Higashimine, Koichi; Porzio, William; Murata, Hideyuki

    2012-07-05

    Graded bilayer solar cells have proven to be at least as efficient as the bulk heterojunctions when it comes to the Poly(3-hexylthiophene) (P3HT) - [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) donor-acceptor system. However, control of the vertical concentration gradient using simple techniques has never been reported. We demonstrate that rubbing the P3HT layer prior to PCBM deposition induces major morphological changes in the active layer. Using the newly introduced energy-dispersive X-ray spectroscopy element mapping technique, we found that rubbing P3HT induces the formation of an ideal vertical donor-acceptor concentration gradient. Furthermore, the P3HT crystallites undergo a molecular reorientation from edge-on to face-on configuration inducing a better charge transport in the vertical direction. The combination of these two major morphological changes leads to the fabrication of high-performance solar cells that exhibit, to date, the record efficiencies for spin-coated graded bilayers solar cells.

  7. [Systems with a concentration gradient have no potential energy but have the ability to do useful work].

    Science.gov (United States)

    Bazhin, N M

    2015-01-01

    The systems with the concentration gradient have no potential energy for heat and useful work production. Nevertheless, they have the ability to do useful work due to the heat dragged from the environment using, for instance, electrodes in the concentration cells. The second law of thermodynamics is not violated: work process occurred due to the heat dragged from the environment is coupled with the process of concentration leveling.

  8. Circulating concentrations of stem-cell-mobilizing cytokines are associated with levels of osteoprogenitor cells and aortic calcification severity

    International Nuclear Information System (INIS)

    Pal, S.N.; Clancy, P.; Golledge, J.

    2011-01-01

    The background of this study was to investigate the association between aortic calcification, concentrations of stem-cell-mobilizing cytokines and osteocalcin-positive mononuclear cells in a mouse model and patients with peripheral artery disease. We estimated the concentration of the stem-cell-mobilizing cytokines stromal cell-derived factor α (SDF-1α), granulocyte colony stimulating factor and stem cell factor in a mouse model of aortic calcification developed in osteoprotegerin-deficient (OPG -/- ) mice, as well as in patient plasma samples. Calcification was estimated by a colorimetric assay of extracts of harvested mice aortas and by computed tomographic angiogram images in patients. The cytokine concentrations were assessed for association with the severity of calcification and the percentage of osteocalcin-positive mononuclear cells (OCN + MNC) using non-parametric analysis. The serum concentration of stromal SDF-1α and granulocyte-colony stimulating factor (G-CSF) were significantly greater in OPG -/- compared to control mice. The percentage of circulating OCN + MNC was correlated to the concentration of SDF-1α in OPG -/- mice. These cytokines also correlated with the severity of calcification in OPG -/- mice. Patients with more severe calcification had a higher plasma concentration of the cytokines than those with less marked aortic calcification. The concentrations also correlated with circulating OCN + MNC and aortic calcification volumes. The association between stem cell cytokines, OCN + MNC and calcification suggests a possible role of bone-derived osteoprogenitor cells in the pathogenesis of vascular calcification. (author)

  9. Design optimization of ultra-high concentrator photovoltaic system using two-stage non-imaging solar concentrator

    Science.gov (United States)

    Wong, C.-W.; Yew, T.-K.; Chong, K.-K.; Tan, W.-C.; Tan, M.-H.; Lim, B.-H.

    2017-11-01

    This paper presents a systematic approach for optimizing the design of ultra-high concentrator photovoltaic (UHCPV) system comprised of non-imaging dish concentrator (primary optical element) and crossed compound parabolic concentrator (secondary optical element). The optimization process includes the design of primary and secondary optics by considering the focal distance, spillage losses and rim angle of the dish concentrator. The imperfection factors, i.e. mirror reflectivity of 93%, lens’ optical efficiency of 85%, circumsolar ratio of 0.2 and mirror surface slope error of 2 mrad, were considered in the simulation to avoid the overestimation of output power. The proposed UHCPV system is capable of attaining effective ultra-high solar concentration ratio of 1475 suns and DC system efficiency of 31.8%.

  10. Photovoltaic modules with cylindrical waveguides in a system for the secondary concentration of solar radiation

    Science.gov (United States)

    Andreev, V. M.; Davidyuk, N. Yu.; Ionova, E. A.; Rumyantsev, V. D.

    2013-09-01

    The parameters of the concentrating photoelectric modules with triple-junction (InGaP/GaAs/Ge) solar cells whose focusing system contains an original secondary optical element are studied. The element consists of a plane-convex lens in optical contact with the front surface of an intermediate glass plate and a cylindrical waveguide that is located on the rear side of the glass plate above the surface of the solar element. It is demonstrated that the structure of the secondary optical element provides a wide misorientation characteristic of the concentrator and the cylindrical waveguide allows a more uniform radiation density over the surface of the solar cell. The effect of chromatic aberration in the primary and secondary optical systems on the parameters of photoelectric modules is analyzed. It is demonstrated that the presence of waveguides with a length of 3-5 mm leads to effective redistribution of radiation over the surface of the solar cell whereas shorter and longer waveguides provide the local concentration of radiation at the center of the photodetecting area.

  11. FRET imaging of hemoglobin concentration in Plasmodium falciparum-infected red cells.

    Directory of Open Access Journals (Sweden)

    Alessandro Esposito

    Full Text Available During its intraerythrocytic asexual reproduction cycle Plasmodium falciparum consumes up to 80% of the host cell hemoglobin, in large excess over its metabolic needs. A model of the homeostasis of falciparum-infected red blood cells suggested an explanation based on the need to reduce the colloid-osmotic pressure within the host cell to prevent its premature lysis. Critical for this hypothesis was that the hemoglobin concentration within the host cell be progressively reduced from the trophozoite stage onwards.The experiments reported here were designed to test this hypothesis by direct measurements of the hemoglobin concentration in live, infected red cells. We developed a novel, non-invasive method to quantify the hemoglobin concentration in single cells, based on Förster resonance energy transfer between hemoglobin molecules and the fluorophore calcein. Fluorescence lifetime imaging allowed the quantitative mapping of the hemoglobin concentration within the cells. The average fluorescence lifetimes of uninfected cohorts was 270+/-30 ps (mean+/-SD; N = 45. In the cytoplasm of infected cells the fluorescence lifetime of calcein ranged from 290+/-20 ps for cells with ring stage parasites to 590+/-13 ps and 1050+/-60 ps for cells with young trophozoites and late stage trophozoite/early schizonts, respectively. This was equivalent to reductions in hemoglobin concentration spanning the range from 7.3 to 2.3 mM, in line with the model predictions. An unexpected ancillary finding was the existence of a microdomain under the host cell membrane with reduced calcein quenching by hemoglobin in cells with mature trophozoite stage parasites.The results support the predictions of the colloid-osmotic hypothesis and provide a better understanding of the homeostasis of malaria-infected red cells. In addition, they revealed the existence of a distinct peripheral microdomain in the host cell with limited access to hemoglobin molecules indicating the

  12. Red blood cells sensitivity to oxidative stress in the presence of low concentrations of uranium compound

    Energy Technology Data Exchange (ETDEWEB)

    Shevchenko, O.G. [Institute of Biology, Komi Scientific Centre, Ural Branch of Russian Academy of Sciences, 167982, Syktyvkar (Russian Federation)

    2014-07-01

    Uranium is a natural radioactive element widespread in biosphere. There are a few works that examined cellular and molecular mechanisms of uranium toxicity. Red blood cells are classical model to investigate toxicity mechanisms on cell membrane system. The aim of present work is to study the effect of uranyl ion in nano-molar concentrations on erythrocytes sensitivity (in vitro) to factors provoking acute oxidative stress. Uranyl ions were added to suspension of mice red blood cells in PBS as UO{sub 2}Cl{sub 2} solution. Samples were incubated in a thermostatic shaker at 37 deg. C during 3-5 hours. Than acute oxidative stress was induced by H{sub 2}O{sub 2} (0.9 mM) or AAPH (5 mM) solutions. Destabilization of the membrane was induced by nonionic detergent Triton X-100. The hemolysis degree and the content of LPO secondary products reacting with 2-thiobarbituric acid in the incubation mixture were determined spectrophotometrically. The ratio of hemoglobin various forms (oxyHb, metHb and ferrylHb) was calculated taking into account extinction coefficients. It was shown that uranyl chloride enhances cell sensitivity to nonionic detergent Triton X-100 effects, indicating alterations of membrane acyl chain order due to contact with the radionuclide ions. Uranium exposure also caused an increase in the cell sensitivity to the AAPH effects, resulted in a decrease in red cell survival rate, a sharp increase in accumulation of hemoglobin oxidation products and a slight increase in the concentration of LPO secondary products. Thus, uranyl ions change physicochemical properties of the erythrocyte membranes that resulted in increased sensitivity to effects of peroxyl radicals formed by thermal decomposition of AAPH. On the contrary, use of another source of free radicals - H{sub 2}O{sub 2} - after uranyl ions exposure resulted in marked decrease of oxidative hemolysis, inhibition of LPO and hemoglobin oxidation. Since the uranium chemical properties similar to properties of

  13. Encystment of Vermamoeba (Hartmannella) vermiformis: Effects of environmental conditions and cell concentration.

    Science.gov (United States)

    Fouque, Emilie; Trouilhé, Marie-Cécile; Thomas, Vincent; Humeau, Philippe; Héchard, Yann

    2014-11-01

    Vermamoeba vermiformis is a free-living amoeba (FLA) which is widely distributed in the environment. It is known to colonize water systems and to be a reservoir of pathogenic bacteria, such as Legionella pneumophila. For these reasons the control of V. vermiformis represents an important health issue. However, FLA may be resistant to disinfection treatments due to the process of encystment. Thereby, it is important to better understand factors influencing this process. In this aim, we investigated the effect of temperature, pH, osmotic pressure and cell concentration on the encystment of two V. vermiformis strains. Encystment was quite fast, with a 100% encystment rate being observed after 9h of incubation. For the two strains, an optimal encystment was obtained at 25 and 37°C. Concerning pH and osmotic pressure, there were different effects on the encystment according to the tested strains. For the reference strain (ATCC 50237), the patterns of encystment were similar for pH comprised between 5 and 9 and for KCl concentrations ranging from 0.05 to 0.2 mol L(-1). For the environmental strain (172A) an optimal encystment was obtained for basic pH (8 and 9) and for a concentration in KCl of 0.1 mol L(-1). The results also clearly demonstrated that the encystment rate increased with cell concentration, suggesting that there is an inter-amoebal communication. The present study establish for the first time environmental conditions favoring encystment and would lay the foundations to better control the encystment of V. vermiformis. Copyright © 2014 Elsevier Inc. All rights reserved.

  14. Pneumatic System for Concentration of Micrometer-Size Lunar Soil

    Science.gov (United States)

    McKay, David; Cooper, Bonnie

    2012-01-01

    A report describes a size-sorting method to separate and concentrate micrometer- size dust from a broad size range of particles without using sieves, fluids, or other processes that may modify the composition or the surface properties of the dust. The system consists of four processing units connected in series by tubing. Samples of dry particulates such as lunar soil are introduced into the first unit, a fluidized bed. The flow of introduced nitrogen fluidizes the particulates and preferentially moves the finer grain sizes on to the next unit, a flat plate impactor, followed by a cyclone separator, followed by a Nuclepore polycarbonate filter to collect the dust. By varying the gas flow rate and the sizes of various orifices in the system, the size of the final and intermediate particles can be varied to provide the desired products. The dust can be collected from the filter. In addition, electron microscope grids can be placed on the Nuclepore filter for direct sampling followed by electron microscope characterization of the dust without further handling.

  15. Plasma D-dimer concentration in patients with systemic sclerosis

    Directory of Open Access Journals (Sweden)

    Montagnana Martina

    2006-01-01

    Full Text Available Abstract Background Systemic sclerosis (SSc is an autoimmune disorder of the connective tissue characterized by widespread vascular lesions and fibrosis. Little is known so far on the activation of the hemostatic and fibrinolytic systems in SSc, and most preliminary evidences are discordant. Methods To verify whether SSc patients might display a prothrombotic condition, plasma D-dimer was assessed in 28 consecutive SSc patients and in 33 control subjects, matched for age, sex and environmental habit. Results and discussion When compared to healthy controls, geometric mean and 95% confidence interval (IC95% of plasma D-dimer were significantly increased in SSc patients (362 ng/mL, IC 95%: 361–363 ng/mL vs 229 ng/mL, IC95%: 228–231 ng/mL, p = 0.005. After stratifying SSc patients according to disease subset, no significant differences were observed between those with limited cutaneous pattern and controls, whereas patients with diffuse cutaneous pattern displayed substantially increased values. No correlation was found between plasma D-dimer concentration and age, sex, autoantibody pattern, serum creatinine, erythrosedimentation rate, nailfold videocapillaroscopic pattern and pulmonary involvement. Conclusion We demonstrated that SSc patients with diffuse subset are characterized by increased plasma D-dimer values, reflecting a potential activation of both the hemostatic and fibrinolytic cascades, which might finally predispose these patients to thrombotic complications.

  16. Direct measurement of local dissolved oxygen concentration spatial profiles in a cell culture environment.

    Science.gov (United States)

    Kagawa, Yuki; Matsuura, Katsuhisa; Shimizu, Tatsuya; Tsuneda, Satoshi

    2015-06-01

    Controlling local dissolved oxygen concentration (DO) in media is critical for cell or tissue cultures. Various biomaterials and culture methods have been developed to modulate DO. Direct measurement of local DO in cultures has not been validated as a method to test DO modulation. In the present study we developed a DO measurement system equipped with a Clark-type oxygen microelectrode manipulated with 1 μm precision in three-dimensional space to explore potential applications for tissue engineering. By determining the microelectrode tip position precisely against the bottom plane of culture dishes with rat or human cardiac cells in static monolayer culture, we successfully obtained spatial distributions of DO in the medium. Theoretical quantitative predictions fit the obtained data well. Based on analyses of the variance between samples, we found the data reflected "local" oxygen consumption in the vicinity of the microelectrode and the detection of temporal changes in oxygen consumption rates of cultured cells was limited by the diffusion rate of oxygen in the medium. This oxygen measuring system monitors local oxygen consumption and production with high spatial resolution, and can potentially be used with recently developed oxygen modulating biomaterials to design microenvironments and non-invasively monitor local DO dynamics during culture. © 2015 Wiley Periodicals, Inc.

  17. High temperature helical tubular receiver for concentrating solar power system

    Science.gov (United States)

    Hossain, Nazmul

    In the field of conventional cleaner power generation technology, concentrating solar power systems have introduced remarkable opportunity. In a solar power tower, solar energy concentrated by the heliostats at a single point produces very high temperature. Falling solid particles or heat transfer fluid passing through that high temperature region absorbs heat to generate electricity. Increasing the residence time will result in more heat gain and increase efficiency. A novel design of solar receiver for both fluid and solid particle is approached in this paper which can increase residence time resulting in higher temperature gain in one cycle compared to conventional receivers. The helical tubular solar receiver placed at the focused sunlight region meets the higher outlet temperature and efficiency. A vertical tubular receiver is modeled and analyzed for single phase flow with molten salt as heat transfer fluid and alloy625 as heat transfer material. The result is compared to a journal paper of similar numerical and experimental setup for validating our modeling. New types of helical tubular solar receivers are modeled and analyzed with heat transfer fluid turbulent flow in single phase, and granular particle and air plug flow in multiphase to observe the temperature rise in one cyclic operation. The Discrete Ordinate radiation model is used for numerical analysis with simulation software Ansys Fluent 15.0. The Eulerian granular multiphase model is used for multiphase flow. Applying the same modeling parameters and boundary conditions, the results of vertical and helical receivers are compared. With a helical receiver, higher temperature gain of heat transfer fluid is achieved in one cycle for both single phase and multiphase flow compared to the vertical receiver. Performance is also observed by varying dimension of helical receiver.

  18. Advances towards reliable identification and concentration determination of rare cells in peripheral blood

    Science.gov (United States)

    Alemany Server, R.; Martens, D.; Jans, K.; Bienstman, P.; Hill, D.

    2016-03-01

    Through further development, integration and validation of micro-nano-bio and biophotonics systems FP7 CanDo is developing an instrument that will permit highly reproducible and reliable identification and concentration determination of rare cells in peripheral blood for two key societal challenges, early and low cost anti-cancer drug efficacy determination and cancer diagnosis/monitoring. A cellular link between the primary malignant tumour and the peripheral metastases, responsible for 90% of cancerrelated deaths, has been established in the form of circulating tumour cells (CTCs) in peripheral blood. Furthermore, the relatively short survival time of CTCs in peripheral blood means that their detection is indicative of tumour progression thereby providing in addition to a prognostic value an evaluation of therapeutic efficacy and early recognition of tumour progression in theranostics. In cancer patients however blood concentrations are very low (=1 CTC/1E9 cells) and current detection strategies are too insensitive, limiting use to prognosis of only those with advanced metastatic cancer. Similarly, problems occur in therapeutics with anti-cancer drug development leading to lengthy and costly trials often preventing access to market. The novel cell separation/Raman analysis technologies plus nucleic acid based molecular characterization of the CanDo platform will provide an accurate CTC count with high throughput and high yield meeting both key societal challenges. Being beyond the state of art it will lead to substantial share gains not just in the high end markets of drug discovery and cancer diagnostics but due to modular technologies also in others. Here we present preliminary DNA hybridization sensing results.

  19. Concentration-dependent fluorescence live-cell imaging and tracking of intracellular nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Ji Hye; Joo, Sang-Woo [Department of Chemistry, Soongsil University, Seoul 156-743 (Korea, Republic of); Cho, Keunchang [Logos Biosystems, Incorporated, Anyang 431-070 (Korea, Republic of); Lee, So Yeong, E-mail: leeso@snu.ac.kr, E-mail: sjoo@ssu.ac.kr [Laboratory of Pharmacology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 151-742 (Korea, Republic of)

    2011-06-10

    Using live-cell imaging techniques we investigated concentration-dependent intracellular movements of fluorescence nanoparticles (NPs) in real-time after their entry into HeLa cells via incubation. Intracellular particle traces appeared to be a mixture of both random and fairly unidirectional movements of the particles. At rather low concentrations of NPs, a majority of the non-random intracellular particle trajectories are assumed to mostly go along microtubule networks after endocytosis, as evidenced from the inhibition test with nocodazole. On the other hand, as the concentrations of NPs increased, random motions were more frequently observed inside the cells.

  20. Concentration-dependent fluorescence live-cell imaging and tracking of intracellular nanoparticles

    International Nuclear Information System (INIS)

    Seo, Ji Hye; Joo, Sang-Woo; Cho, Keunchang; Lee, So Yeong

    2011-01-01

    Using live-cell imaging techniques we investigated concentration-dependent intracellular movements of fluorescence nanoparticles (NPs) in real-time after their entry into HeLa cells via incubation. Intracellular particle traces appeared to be a mixture of both random and fairly unidirectional movements of the particles. At rather low concentrations of NPs, a majority of the non-random intracellular particle trajectories are assumed to mostly go along microtubule networks after endocytosis, as evidenced from the inhibition test with nocodazole. On the other hand, as the concentrations of NPs increased, random motions were more frequently observed inside the cells.

  1. Development of manufacturing capability for high-concentration, high-efficiency silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Sinton, R.A.; Verlinden, P.J.; Crane, R.A.; Swanson, R.N. [SunPower Corp., Sunnyvale, CA (United States)

    1996-10-01

    This report presents a summary of the major results from a program to develop a manufacturable, high-efficiency silicon concentrator solar cell and a cost-effective manufacturing facility. The program was jointly funded by the Electric Power Research Institute, Sandia National Laboratories through the Concentrator Initiative, and SunPower Corporation. The key achievements of the program include the demonstration of 26%-efficient silicon concentrator solar cells with design-point (20 W/cm{sup 2}) efficiencies over 25%. High-performance front-surface passivations; that were developed to achieve this result were verified to be absolutely stable against degradation by 475 days of field exposure at twice the design concentration. SunPower demonstrated pilot production of more than 1500 of these cells. This cell technology was also applied to pilot production to supply 7000 17.7-cm{sup 2} one-sun cells (3500 yielded wafers) that demonstrated exceptional quality control. The average efficiency of 21.3% for these cells approaches the peak efficiency ever demonstrated for a single small laboratory cell within 2% (absolute). Extensive cost models were developed through this program and calibrated by the pilot-production project. The production levels achieved indicate that SunPower could produce 7-10 MW of concentrator cells per year in the current facility based upon the cell performance demonstrated during the program.

  2. Cell growth, intracellular calcium concentration and metabolic cooperation measured in cells exposed to 50 Hz electromagnetic fields

    International Nuclear Information System (INIS)

    Skauli, K.S.

    1996-08-01

    Colony-forming efficiency, DNA/protein and DNA/cell were measured in cells exposed to magnetic fields of 0.2 and 1 mT at a frequency of 50 Hz. Intracellular calcium concentrations were measured in cells exposed to 0.3 and 1 mT at 50 Hz. Metabolic cooperation was measured in cells exposed to 1 mT at 50 Hz. No significant effects of the fields were observed. 20 refs., 10 figs

  3. Concentration photovoltaic–thermal energy co-generation system using nanofluids for cooling and heating

    International Nuclear Information System (INIS)

    Xu, Zelin; Kleinstreuer, Clement

    2014-01-01

    Highlights: • Pilot study for improved CPV/T system efficiencies when using nanofluids as coolant. • Validated computational efficiency analysis of a 2-D combined CPV/T model. • Use of a new thermal conductivity model for nanofluids. • Nanofluid-based co-generation system a preferable to water-based systems. - Abstract: New designs of dual concentration photovoltaic–thermal (CPV/T) systems can provide both electrical and thermal energy, while reducing solar cell material usage via optical techniques. The overall system efficiency can be improved by using advanced dual-purpose liquids with enhanced heat transfer characteristics, such as nanofluids. In this paper the use of nanofluids, i.e., dilute nanoparticle suspensions in liquids, are considered for improved efficiency of a CPV/T system for the first time. Specifically, a 2-D model coupling thermal analysis and computational fluid dynamics simulations has been developed to calculate efficiencies of individual subsystems as well as the overall system. A new thermal conductivity model for nanofluids, which was validated with experimental data sets, was employed. The electrical and thermal performances of the system were evaluated for different climatic conditions. The results show that using nanofluids improves the electrical and total efficiencies of the system, especially when using silicon solar cells. For example, if the nanofluid outlet temperature of the solar cell is set to 62 °C via a controlled flow rate, the system overall efficiency could reach 70% with electrical and thermal contributions amounting to 11% and 59%, respectively. In summary, a nanofluid-based system is preferable to water-based systems in the long run

  4. Polymethylmethacrylate-based luminescent solar concentrators with bottom-mounted solar cells

    International Nuclear Information System (INIS)

    Zhang, Yi; Sun, Song; Kang, Rui; Zhang, Jun; Zhang, Ningning; Yan, Wenhao; Xie, Wei; Ding, Jianjun; Bao, Jun; Gao, Chen

    2015-01-01

    Graphical abstract: - Highlights: • Bottom-mounted luminescent solar concentrators on dye-doped plates were studied. • The mechanism of transport process was proposed. • The fabricated luminescent solar concentrator achieved a gain of 1.38. • Power conversion efficiency of 5.03% was obtained with cell area coverage of 27%. • The lowest cost per watt of $1.89 was optimized with cell area coverage of 18%. - Abstract: Luminescent solar concentrators offer an attractive approach to concentrate sunlight economically without tracking, but the narrow absorption band of luminescent materials hinders their further development. This paper describes bottom-mounted luminescent solar concentrators on dye-doped polymethylmethacrylate plates that absorb not only the waveguided light but also the transmitted sunlight and partial fluorescent light in the escape cone. A series of bottom-mounted luminescent solar concentrators with size of 78 mm × 78 mm × 7 mm were fabricated and their gain and power conversion efficiency were investigated. The transport process of the waveguided light and the relationship between the bottom-mounted cells were studied to optimize the performance of the device. The bottom-mounted luminescent solar concentrator with cell area coverage of 9% displayed a cell gain of 1.38, to our best knowledge, which is the highest value for dye-doped polymethylmethacrylate plate luminescent solar concentrators. Power conversion efficiency as high as 5.03% was obtained with cell area coverage of 27%. Furthermore, the bottom-mounted luminescent solar concentrator was found to have a lowest cost per watt of $1.89 with cell area coverage of 18%. These results suggested that the fabricated bottom-mounted luminescent solar concentrator may have a potential in low-cost building integrated photovoltaic application

  5. Temporal Microbial Community Dynamics in Microbial Electrolysis Cells – Influence of Acetate and Propionate Concentration

    KAUST Repository

    Rao, Hari Ananda

    2017-07-20

    Microbial electrolysis cells (MECs) are widely considered as a next generation wastewater treatment system. However, fundamental insight on the temporal dynamics of microbial communities associated with MEC performance under different organic types with varied loading concentrations is still unknown, nevertheless this knowledge is essential for optimizing this technology for real-scale applications. Here, the temporal dynamics of anodic microbial communities associated with MEC performance was examined at low (0.5 g COD/L) and high (4 g COD/L) concentrations of acetate or propionate, which are important intermediates of fermentation of municipal wastewaters and sludge. The results showed that acetate-fed reactors exhibited higher performance in terms of maximum current density (I: 4.25 ± 0.23 A/m), coulombic efficiency (CE: 95 ± 8%), and substrate degradation rate (98.8 ± 1.2%) than propionate-fed reactors (I: 2.7 ± 0.28 A/m; CE: 68 ± 9.5%; substrate degradation rate: 84 ± 13%) irrespective of the concentrations tested. Despite of the repeated sampling of the anodic biofilm over time, the high-concentration reactors demonstrated lower and stable performance in terms of current density (I: 1.1 ± 0.14 to 4.2 ± 0.21 A/m), coulombic efficiency (CE: 44 ± 4.1 to 103 ± 7.2%) and substrate degradation rate (64.9 ± 6.3 to 99.7 ± 0.5%), while the low-concentration reactors produced higher and dynamic performance (I: 1.1 ± 0.12 to 4.6 ± 0.1 A/m; CE: 52 ± 2.5 to 105 ± 2.7%; substrate degradation rate: 87.2 ± 0.2 to 99.9 ± 0.06%) with the different substrates tested. Correlating reactor\\'s performance with temporal dynamics of microbial communities showed that relatively similar anodic microbial community composition but with varying relative abundances was observed in all the reactors despite differences in the substrate and concentrations tested. Particularly, Geobacter was the predominant bacteria on the anode biofilm of all MECs over time suggesting its

  6. Fuel cell-fuel cell hybrid system

    Science.gov (United States)

    Geisbrecht, Rodney A.; Williams, Mark C.

    2003-09-23

    A device for converting chemical energy to electricity is provided, the device comprising a high temperature fuel cell with the ability for partially oxidizing and completely reforming fuel, and a low temperature fuel cell juxtaposed to said high temperature fuel cell so as to utilize remaining reformed fuel from the high temperature fuel cell. Also provided is a method for producing electricity comprising directing fuel to a first fuel cell, completely oxidizing a first portion of the fuel and partially oxidizing a second portion of the fuel, directing the second fuel portion to a second fuel cell, allowing the first fuel cell to utilize the first portion of the fuel to produce electricity; and allowing the second fuel cell to utilize the second portion of the fuel to produce electricity.

  7. Low concentrations of doxycycline attenuates FasL-induced apoptosis in HeLa cells.

    Science.gov (United States)

    Yoon, Jung Mi; Koppula, Sushruta; Huh, Se Jong; Hur, Sun Jin; Kim, Chan Gil

    2015-07-24

    Doxycycline (DC) has been shown to possess non-antibiotic properties including Fas/Fas Ligand (FasL)-mediated apoptosis against several tumor types in the concentration range of 10-40 µg/mL. However, the effect of DC in apoptotic signaling at much low concentrations was not studied. The present study investigated the attenuation effect of low dose of DC on FasL-induced apoptosis in HeLa cell by the methods of MTT assay, fluorescence microscopy, DNA fragmentation, flow cytometry analysis, and western blotting. In the present findings we showed that low concentration of DC (HeLa cells. FasL treatment to HeLa cells resulted in a concentration-dependent induction of cell death, and treatment with low concentrations of DC (0.1-2 µg/mL) significantly (p cell death as measured by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Further, the FasL-induced apoptotic features in HeLa cells, such as morphological changes, DNA fragmentation and cell cycle arrest was also inhibited by DC (0.5 µg/mL). Tetracycline and minocycline also showed similar anti-apoptotic effects but were not significant when compared to DC, tested at same concentrations. Further, DC (0.01-16 µg/mL) did not influence the hydrogen peroxide- or cisplatin-induced intrinsic apoptotic pathway in HeLa cells. Protein analysis using Western blotting confirmed that FasL-induced cleavage/activation of caspase-8 and caspase-3, were inhibited by DC treatment at low concentration (0.5 µg/mL). Considering the overall data, we report for the first time that DC exhibited anti-apoptotic effects at low concentrations in HeLa cells by inhibition of caspase activation via FasL-induced extrinsic pathway.

  8. Bone marrow concentrate for autologous transplantation in minipigs. Characterization and osteogenic potential of mesenchymal stem cells.

    Science.gov (United States)

    Herten, M; Grassmann, J P; Sager, M; Benga, L; Fischer, J C; Jäger, M; Betsch, M; Wild, M; Hakimi, M; Jungbluth, P

    2013-01-01

    Autologous bone marrow plays an increasing role in the treatment of bone, cartilage and tendon healing disorders. Cell-based therapies display promising results in the support of local regeneration, especially therapies using intra-operative one-step treatments with autologous progenitor cells. In the present study, bone marrow-derived cells were concentrated in a point-of-care device and investigated for their mesenchymal stem cell (MSC) characteristics and their osteogenic potential. Bone marrow was harvested from the iliac crest of 16 minipigs. The mononucleated cells (MNC) were concentrated by gradient density centrifugation, cultivated, characterized by flow cytometry and stimulated into osteoblasts, adipocytes, and chondrocytes. Cell differentiation was investigated by histological and immunohistological staining of relevant lineage markers. The proliferation capacity was determined via colony forming units of fibroblast and of osteogenic alkaline-phosphatase-positive-cells. The MNC could be enriched 3.5-fold in nucleated cell concentrate in comparison to bone marrow. Flow cytometry analysis revealed a positive signal for the MSC markers. Cells could be differentiated into the three lines confirming the MSC character. The cellular osteogenic potential correlated significantly with the percentage of newly formed bone in vivo in a porcine metaphyseal long-bone defect model. This study demonstrates that bone marrow concentrate from minipigs display cells with MSC character and their osteogenic differentiation potential can be used for osseous defect repair in autologous transplantations.

  9. Concentration characteristics and cell arrangement in luminescent concentrator PV modules; Keiko shukogata taiyo denchi module no cell haichi to shuko tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Inamura, A. [Science University of Tokyo, Tokyo (Japan); Sakuta, K. [Electrotechnical Laboratory, Tsukuba (Japan)

    1997-11-25

    A luminescent concentrator PV module requires no tracking equipment and can use scattered light. A mini PV module was prepared from a luminescent plate of 100times100times3mm, and a single-crystalline PV cell of 100times20mm. Characteristics of various prototype modules with different PV cell areas and cell arrangements were also measured. Four kinds of edge reflecting materials with different reflectances by various white coating were applied to Al sashes for module frames, and each sash was fixed on one edge of the luminescent plate. In experiment, 3 other edges were covered with black tapes to reduce each reflectance to 0%. Although PV module output was affected by reflectance of edges, the output was satisfactory at 90% or more in reflectance showing no difference in output. A concentrating efficiency decreased with an increase in luminescent plate (concentrator) area, while it was improved by cell arrangement with short optical pass length, and cell arrangement hardly affected by edge reflection. 4 refs., 7 figs.

  10. A Novel Concentrator Photovoltaic (CPV System with the Improvement of Irradiance Uniformity and the Capturing of Diffuse Solar Radiation

    Directory of Open Access Journals (Sweden)

    Nguyen Xuan Tien

    2016-09-01

    Full Text Available This paper proposes a novel concentrator photovoltaic (CPV system with improved irradiation uniformity and system efficiency. CPV technology is very promising its for highly efficient solar energy conversion. A conventional CPV system usually uses only one optical component, such as a refractive Fresnel lens or a reflective parabolic dish, to collect and concentrate solar radiation on the solar cell surface. Such a system creates strongly non-uniform irradiation distribution on the solar cell, which tends to cause hot spots, current mismatch, and degrades the overall efficiency of the system. Additionally, a high-concentration CPV system is unable to collect diffuse solar radiation. In this paper, we propose a novel CPV system with improved irradiation uniformity and collection of diffuse solar radiation. The proposed system uses a Fresnel lens as a primary optical element (POE to concentrate and focus the sunlight and a plano-concave lens as a secondary optical element (SOE to uniformly distribute the sunlight over the surface of multi-junction (MJ solar cells. By using the SOE, the irradiance uniformity is significantly improved in the system. Additionally, the proposed system also captures diffuse solar radiation by using an additional low-cost solar cell surrounding MJ cells. In our system, incident direct solar radiation is captured by MJ solar cells, whereas incident diffuse solar radiation is captured by the low-cost solar cell. Simulation models were developed using a commercial optical simulation tool (LightTools™. The irradiance uniformity and efficiency of the proposed CPV system were analyzed, evaluated, and compared with those of conventional CPV systems. The analyzed and simulated results show that the CPV system significantly improves the irradiance uniformity as well as the system efficiency compared to the conventional CPV systems. Numerically, for our simulation models, the designed CPV with the SOE and low-cost cell provided

  11. Cytotoxic and genotoxic effects of high concentrations of the immunosuppressive drugs cyclosporine and tacrolimus in MRC-5 cells.

    Science.gov (United States)

    Cilião, H L; Ribeiro, D L; Camargo-Godoy, R B O; Specian, A F L; Serpeloni, J M; Cólus, I M S

    2015-02-01

    Immunosuppressive drugs are used to suppress immune system activity in transplant patients and reduce the risk of organ rejection. The present study evaluated the potential cytotoxic, genotoxic and mutagenic of the immunosuppressive drugs cyclosporine (CsA) and tacrolimus (FK-506) on normal human fibroblasts (MRC-5 cells). Based on plasma concentrations of the immunosuppressive drugs, which were obtained from the records of kidney transplant patients at the Kidney Institute of Londrina, Brazil, 11 concentrations of each immunosuppressive were chosen to evaluate cell viability using the MTT assay. From these results, CsA and FK-506 concentrations of 135, 300, 675, and 1520 ng/ml and 8, 16, 24, and 32 ng/ml, respectively, were evaluated using (i) the comet assay, (ii) the nuclear division index (NDI), (iii) the micronucleus test (CBMN) and (iv) cell proliferation curves generated by quantifying cell numbers and protein levels. In this study, 1520 to 3420 ng/ml CsA decreased cell viability after 48 h of exposure. Genotoxic effects were observed only with a concentration of 1520 ng/ml after 3h of exposure and with concentrations of 675 and 1520 ng/ml after 24h of exposure. Mutagenic effects were observed only for the concentration of 1520 ng/ml. FK-506 decreased cell viability after 72 h of exposure for concentrations up to 20 ng/ml; genotoxic effects were observed with concentrations up to 8 ng/ml for both treatment times (3 and 24h) and mutagenic effects were observed with concentrations of 24 and 32 ng/ml after 24h of treatment. The cell proliferation curves demonstrated the absence of cytostatic effects of these drugs, and these data were confirmed by the NDI analysis. Our results suggest that concentrations lower than 300 ng/ml of CsA and 16 ng/ml of FK-506 are safe for use, as they did not induce genotoxic and mutagenic damage or affect MRC-5 cell viability and proliferation. Copyright © 2014 Elsevier GmbH. All rights reserved.

  12. Polyaspartic Acid Concentration Controls the Rate of Calcium Phosphate Nanorod Formation in High Concentration Systems

    Energy Technology Data Exchange (ETDEWEB)

    Krogstad, Daniel V. [Biosystems and; Wang, Dongbo [Biosystems and; Lin-Gibson, Sheng [Biosystems and

    2017-08-31

    Polyelectrolytes are known to greatly affect calcium phosphate (CaP) mineralization. The reaction kinetics as well as the CaP phase, morphology and aggregation state depend on the relative concentrations of the polyelectrolyte and the inorganic ions in a complex, nonlinear manner. This study examines the structural evolution and kinetics of polyaspartic acid (pAsp) directed CaP mineralization at high concentrations of polyelectrolytes, calcium, and total phosphate (19–30 mg/mL pAsp, 50–100 mM Ca2+, Ca/P = 2). Using a novel combination of characterization techniques including cryogenic transmission electron microscopy (cryo-TEM), spectrophotometry, X-ray total scattering pair distribution function analysis, and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), it was determined that the CaP mineralization occurred over four transition steps. The steps include the formation of aggregates of pAsp stabilized CaP spherical nanoparticles (sNP), crystallization of sNP, oriented attachment of the sNP into nanorods, and further crystallization of the nanorods. The intermediate aggregate sizes and the reaction kinetics were found to be highly polymer concentration dependent while the sizes of the particles were not concentration dependent. This study demonstrates the complex role of pAsp in controlling the mechanism as well as the kinetics of CaP mineralization.

  13. Reuse of the Reflective Light and the Recycle Heat Energy in Concentrated Photovoltaic System

    Directory of Open Access Journals (Sweden)

    Hsin-Chien Chen

    2013-01-01

    Full Text Available A complex solar unit with microcrystalline silicon solar cells placed around the centered GaAs triple junction solar cell has been proposed and carried out. With the same illumination area and intensity, the total resultant power shows that the excess microcrystalline silicon solar cells increase the total output power by 13.2% by absorbing the reflective light from the surface of optical collimators. Furthermore, reusing the residual heat energy generated from the above-mentioned mechanism helps to increase the output power by around 14.1%. This mechanism provides a simple method to enhance the utility rate of concentrated photovoltaic (CPV system. Such concept can be further applied to the aerospace industry and the development of more efficient CPV solar energy applications.

  14. Development of a microfluidic perfusion 3D cell culture system

    Science.gov (United States)

    Park, D. H.; Jeon, H. J.; Kim, M. J.; Nguyen, X. D.; Morten, K.; Go, J. S.

    2018-04-01

    Recently, 3-dimensional in vitro cell cultures have gained much attention in biomedical sciences because of the closer relevance between in vitro cell cultures and in vivo environments. This paper presents a microfluidic perfusion 3D cell culture system with consistent control of long-term culture conditions to mimic an in vivo microenvironment. It consists of two sudden expansion reservoirs to trap incoming air bubbles, gradient generators to provide a linear concentration, and microchannel mixers. Specifically, the air bubbles disturb a flow in the microfluidic channel resulting in the instability of the perfusion cell culture conditions. For long-term stable operation, the sudden expansion reservoir is designed to trap air bubbles by using buoyancy before they enter the culture system. The performance of the developed microfluidic perfusion 3D cell culture system was examined experimentally and compared with analytical results. Finally, it was applied to test the cytotoxicity of cells infected with Ewing’s sarcoma. Cell death was observed for different concentrations of H2O2. For future work, the developed microfluidic perfusion 3D cell culture system can be used to examine the behavior of cells treated with various drugs and concentrations for high-throughput drug screening.

  15. Mechatronics in fuel cell systems

    Energy Technology Data Exchange (ETDEWEB)

    Stefanopoulou, Anna G.; Kyungwon Suh [Mechanical Engineering Department, University of Michigan, 1231 Beal Avenue, Ann Arbor, MI 48109, (United States)

    2007-03-15

    Power generation from fuel cells (FCs) requires the integration of chemical, fluid, mechanical, thermal, electrical, and electronic subsystems. This integration presents many challenges and opportunities in the mechatronics field. This paper highlights important design issues and poses problems that require mechatronics solutions. The paper begins by describing the process of designing a toy school bus powered by hydrogen for an undergraduate student project. The project was an effective and rewarding educational activity that revealed complex systems issues associated with FC technology. (Author)

  16. A method for the control of alumina concentration in aluminum reduction cells

    Directory of Open Access Journals (Sweden)

    Jens G. Balchen

    1992-01-01

    Full Text Available The paper presents a new method for the control of the concentration of the alumina in electrolysis cells for the production of aluminium. The method is based upon the well known fact that apparent resistivity of the cell is a function of the alumina concentration so that the resistivity has the lowest value around the concentration of three per cent and increases in both directions. The method uses the cross correlation between a perturbation of the feed flow of alumina into the cell and the resulting response in measured voltage across the cell. The cross-correlation is proportional to the slope of the resistivity against concentration curve, making it possible to control the alumina flow, to achieve a desired slope. The method has much in common with other methods presently in use which require a much more complicated computation scheme.

  17. Effect of Concentration of Collagen Gel on Functional Activity of Bone Marrow Mesenchymal Stromal Cells.

    Science.gov (United States)

    Nashchekina, Yu A; Yudintceva, N M; Nikonov, P O; Ivanova, E A; Smagina, L V; Voronkina, I V

    2017-05-01

    Collagen I gels with protein concentrations of 1, 2, and 3.5 mg/ml were prepared and embedded in a porous polylactide scaffold to reduce their contraction. Concentration of the gel did not affect its degradation. Collagen gels promoted the formation of cell networks. The cells in the collagen gel with a concentration of 1 mg/ml embedded in polylactide scaffold had elongated spindle-like shape, in contrast to flattened cells in collagen gel of the same concentration not embedded in the scaffold. Stabilization of the collagen gel in the polylactide scaffold promoted active synthesis of laminin and fibronectin by cells as soon as on day 5 of culturing in comparison with that in free collagen substrate.

  18. Determination of algal cell culture (Desmodesmus subspicatus) concentration using a microplate reader

    Czech Academy of Sciences Publication Activity Database

    Kočí, V.; Dragoun, D.; Lukavský, Jaromír

    2006-01-01

    Roč. 165, č. 122 (2006), s. 123-135 ISSN 0342-1120 Institutional research plan: CEZ:AV0Z60050516 Keywords : algal bioassay * microplate spectrophotometry * cell concentration Subject RIV: EF - Botanics

  19. Application of the wavelet image analysis technique to monitor cell concentration in bioprocesses

    Directory of Open Access Journals (Sweden)

    G. J. R. Garófano

    2005-12-01

    Full Text Available The growth of cells of great practical interest, such as, the filamentous cells of bacterium Streptomyces clavuligerus, the yeast Saccharomyces cerevisiae and the insect Spodoptera frugiperda (Sf9 cell, cultivated in shaking flasks with complex media at appropriate temperatures and pHs, was quantified by the new wavelet transform technique. This image analysis tool was implemented using Matlab 5.2 software to process digital images acquired of samples taken of these three types of cells throughoot their cultivation. The values of the average wavelet coefficients (AWCs of simplified images were compared with experimental measurements of cell concentration and with computer-based densitometric measurements. AWCs were shown to be directly proportional to measurements of cell concentration and to densitometric measurements, making evident the great potential of the wavelet transform technique to quantitatively estimate the growth of several types of cells.

  20. Relationship between RFC gene expression and intracellular drug concentration in methotrexate-resistant osteosarcoma cells.

    Science.gov (United States)

    Wang, J J; Li, G J

    2014-07-24

    Osteosarcoma is a primary malignant tumor in adolescents, associated with high mortality and morbidity. The high-dose methotrexate (MTX) chemotherapy used to treat this disease may induce primary or secondary drug resistance, resulting in a reduced effect of comprehensive treatment. In this study, the relationship between reduced folate carrier (RFC) gene expression and intracellular drug concentration in MTX-resistant osteosarcoma cells (Saos-2) was investigated. MTX-resistant human osteosarcoma cells (Saos-2/MTX2.2, Saos-2/MTX4.4) were prepared. The sensitivities of Saos-2 (primary cells), Saos-2/MTX2.2, and Saos-2/MTX4.4 cells to MTX, diamminedichloroplatinum (DDP), ifosfamide (IFO), epirubicine (EPI), adriamycin (ADM), theprubicin (THP), and paclitaxel (PTX) were detected by MTT. The median inhibitory concentration (IC50) and resistance index were measured. Semi-quantitative RT-PCR was used to evaluate the expression of RFC gene in cells. The intracellular (3)H-MTX concentration was determined. Results showed that IC50 of Saos-2/MTX2.2 and Saos-2/MTX4.4 was 4.87 and 12.73 times that of Saos-2, respectively. Both Saos-2/MTX2.2 and Saos-2/MTX4.4 had resistance to IFO, ADM, EPI, THP, and PTX, but not DDP. Compared to Saos-2/MTX2.2 and Saos-2/MTX4.4, the expression of RFC mRNA in Saos-2 was significantly higher. The intracellular (3)H-MTX concentration reached a peak at 50 min. After 70 min, the concentration was maintained at a plateau. During this phase, the (3)H-MTX concentration in Saos-2 cells was 2.15 times higher than the concentration in Saos-2/MTX4.4 cells. The reduced RFC mRNA expression in PTX-resistant osteosarcoma cells may be related to the decrease in intracellular (3)H-MTX concentration.

  1. Biological Effects of Osteoblast-Like Cells on Nanohydroxyapatite Particles at a Low Concentration Range

    Directory of Open Access Journals (Sweden)

    Xiaochen Liu

    2011-01-01

    Full Text Available The biological effects of osteoblast-like MG-63 cells on nanohydroxyapatite (n-HA at the low concentration range (5–25 g/mL for 5 days was investigated. The results showed the viability and actin cytoskeleton of the cells descended with the increase of the concentration of n-HA, and the actin cytoskeleton of cells was depolymerised and became more disordered. Apoptotic rate of cells (1.85%, 1.99%, and 2.29% increased with the increase of n-HA concentration (5, 15, and 25 g/mL and become significantly higher than the control. Total intracellular protein content decreased with n-HA concentration increase, showing significant difference between 25 g/mL and the control, and no significant change of ALP activity was observed at the 5th day. The results revealed that the cell growth was inhibited by n-HA in a concentration-dependent manner, and the obvious biological effects of MG-63 cells on n-HA existed at the low concentration range from 5 to 25 g/mL.

  2. The prognostic value of YKL-40 concentrations in nonmyeloablative conditioning allogeneic hematopoietic cell transplantation

    DEFF Research Database (Denmark)

    Mørup, Anne Mette; Kornblit, Brian; Johansen, Julia S

    2011-01-01

    and plasma YKL-40 concentrations as prognostic biomarkers in a cohort of 149 patients treated with hematopoietic cell transplantation (HCT) after nonmyeloablative conditioning for hematologic malignancies. Recipients with pretransplant YKL-40 concentrations above the age-adjusted 95th percentile (high) had...

  3. Biaxial-Type Concentrated Solar Tracking System with a Fresnel Lens for Solar-Thermal Applications

    Directory of Open Access Journals (Sweden)

    Tsung Chieh Cheng

    2016-04-01

    Full Text Available In this paper, an electromechanical, biaxial-type concentrated solar tracking system was designed for solar-thermal applications. In our tracking system, the sunlight was concentrated by the microstructure of Fresnel lens to the heating head of the Stirling engine and two solar cells were installed to provide the power for tracking system operation. In order to obtain the maximum sun power, the tracking system traces the sun with the altitude-azimuth biaxial tracing method and accurately maintains the sun’s radiation perpendicular to the plane of the heating head. The results indicated that the position of heating head is an important factor for power collection. If the sunlight can be concentrated to completely cover the heating head with small heat loss, we can obtain the maximum temperature of the heating head of the Stirling engine. Therefore, the temperature of heating head can be higher than 1000 °C in our experiment on a sunny day. Moreover, the results also revealed that the temperature decrease of the heating head is less than the power decrease of solar irradiation because of the latent heat of copper and the small heat loss from the heating head.

  4. Commercial Application of a Photovoltaic Concentrator system. Phase I. Final report, 1 June 1978-28 February 1979

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, D.J.; Anderson, E.R.; Bardwell, K.M.

    1980-04-01

    This report documents the design and analysis of the BDM CAPVC (Commercial Application of a Photovoltaic Concentrator) system. The preliminary design, prototype test and evaluation, system analysis, and final design of a large-scale concentrating photovoltaic system are described. The application is on an attractive new office building which represents a large potential market. The photovoltaic concentrating array is a roof-mounted, single-axis linear parabolic trough, using single crystalline silicon photovoltaic cells. A total of 6720 square feet of aperture is focussed on 13,944 PV cells. The photovoltaic system operates in parallel with the local utility in an augmentary loadsharing operating mode. The array is actively cooled and the thermal energy utilized for building heat during winter months. (WHK)

  5. Illumination uniformity issue explored via two-stage solar concentrator system based on Fresnel lens and compound flat concentrator

    International Nuclear Information System (INIS)

    Yeh, Naichia

    2016-01-01

    This paper illustrates details about the solar radiation distribution on the target of a two-stage solar concentrator that combines the Fresnel lens (FL) and the compound flat concentrator (CFC). The paper starts with a review of some FL development milestones such as the two-stage systems and the comparisons of flat vs. curved lenses in addition to the most noteworthy FL-based solar energy application, concentration photovoltaic (CPV). Through the review of the FL based CPV and two-stage concentrators, this study leads to the development of an algorithm to explore the spectrum distribution insight on the receiver of a two-stage (FL plus CFC) solar concentration system. It established the potential for using a correctly positioned 2nd stage reflector of right dimension to selectively redirect the desired spectrum on the target area so as to enhance the concentration flux intensity and uniformity at the same time. The study also helped to chart out the approximate locations of certain spectrum segments on the FL's target area, which is useful for exploring the spectrum control mechanism via the Fresnel lenses. - Highlights: • Map out the approximate locations of spectrum segments on FL's focal area. • Use the 2nd stage reflector to selectively reflect the desired spectrum on target. • Explore the spectrum distribution insight on FL solar concentrators' target area.

  6. Absolute choline concentration measured by quantitative proton MR spectroscopy correlates with cell density in meningioma

    Energy Technology Data Exchange (ETDEWEB)

    Yue, Qiang [University of Tsukuba, Department of Neurosurgery, Institute of Clinical Medicine, Tsukuba Science City, Ibaraki (Japan)]|[West China Hospital of Sichuan University, Huaxi MR Research Center, Department of Radiology, Chengdu (China); Shibata, Yasushi; Kawamura, Hiraku; Matsumura, Akira [University of Tsukuba, Department of Neurosurgery, Institute of Clinical Medicine, Tsukuba Science City, Ibaraki (Japan); Isobe, Tomonori [Kitasato University, Department of Medical Technology, School of Allied Health Sciences, Minato, Tokyo (Japan); Anno, Izumi [University of Tsukuba, Department of Radiology, Institute of Clinical Medicine, Tsukuba, Ibaraki (Japan); Gong, Qi-Yong [West China Hospital of Sichuan University, Huaxi MR Research Center, Department of Radiology, Chengdu (China)]|[University of Liverpool, Division of Medical Imaging, Faculty of Medicine, Liverpool (United Kingdom)

    2009-01-15

    This study was aimed to investigate the relationship between quantitative proton magnetic resonance spectroscopy (1H-MRS) and pathological changes in meningioma. Twenty-two meningioma cases underwent single voxel 1H-MRS (point-resolved spectroscopy sequence, repetition time/echo time = 2,000 ms/68, 136, 272 ms). Absolute choline (Cho) concentration was calculated using tissue water as the internal reference and corrected according to intra-voxel cystic/necrotic parts. Pathological specimens were stained with MIB-1 antibody to measure cell density and proliferation index. Correlation analysis was performed between absolute Cho concentration and cell density and MIB-1 labeled proliferation index. Average Cho concentration of all meningiomas before correction was 2.95 {+-} 0.86 mmol/kg wet weight. It was increased to 3.23 {+-} 1.15 mmol/kg wet weight after correction. Average cell density of all meningiomas was 333 {+-} 119 cells/HPF, and average proliferation index was 2.93 {+-} 5.72%. A linear, positive correlation between cell density and Cho concentration was observed (r = 0.650, P = 0.001). After correction of Cho concentration, the correlation became more significant (r = 0.737, P < 0.001). However, no significant correlation between Cho concentration and proliferation index was found. There seemed to be a positive correlation trend after correction of Cho concentration but did not reach significant level. Absolute Cho concentration, especially Cho concentration corrected according to intra-voxel cystic/necrotic parts, reflects cell density of meningioma. (orig.)

  7. Fuel cell system blower configuration

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Kirtikumar H.; Saito, Kazuo

    2017-11-28

    An exemplary fuel cell system includes a cell stack assembly having a plurality of cathode components and a plurality of anode components. A first reactant blower has an outlet situated to provide a first reactant to the cathode components. A second reactant blower has an outlet situated to provide a second reactant to the anode components. The second reactant blower includes a fan portion that moves the second reactant through the outlet. The second reactant blower also includes a motor portion that drives the fan portion and a bearing portion associated with the fan portion and the motor portion. The motor portion has a motor coolant inlet coupled with the outlet of the first reactant blower to receive some of the first reactant for cooling the motor portion.

  8. 3D-printed concentrator arrays for external light trapping on thin film solar cells

    NARCIS (Netherlands)

    van Dijk, Lourens; Marcus, E. A. Pepijn; Oostra, A. Jolt; Schropp, Ruud E. I.; Di Vece, Marcel

    After our recent demonstration of a 3D-printed external light trap on a small solar cell, we now consider its potential for large solar panels. An external light trap consists of a parabolic concentrator and a spacer that redirects the photons that are reflected by the solar cell back towards the

  9. Fluorescent multiplex cell flow systems and methods

    KAUST Repository

    Merzaban, Jasmeen

    2017-06-01

    Systems and methods are provided for simultaneously assaying cell adhesion or cell rolling for multiple cell specimens. One embodiment provides a system for assaying adhesion or cell rolling of multiple cell specimens that includes a confocal imaging system containing a parallel plate flow chamber, a pump in fluid communication with the parallel plate flow chamber via a flow chamber inlet line and a cell suspension in fluid communication with the parallel plate flow chamber via a flow chamber outlet line. The system also includes a laser scanning system in electronic communication with the confocal imaging system, and a computer in communication with the confocal imaging system and laser scanning system. In certain embodiments, the laser scanning system emits multiple electromagnetic wavelengths simultaneously it cause multiple fluorescent labels having different excitation wavelength maximums to fluoresce. The system can simultaneously capture real-time fluorescence images from at least seven cell specimens in the parallel plate flow chamber.

  10. KOH concentration effect on the cycle life of nickel-hydrogen cells

    Science.gov (United States)

    Lim, H. S.; Verzwyvelt, S. A.

    1985-01-01

    Effects of KOH concentration on the cycle life of a sintered-type nickel electrode were studied in a boiler plate nickel-hydrogen cell at 23 C using an accelerated 45-min cycle regime at 80 percent depth of discharge. The cycle life improved greatly as the KOH concentration decreased, although the initial capacity of the cell decreased slightly. The cycle life improved by a factor of two or more when the KOH concentration was reduced from 36 to 31 percent and by a similar factor from reductions of 31 to 26 percent. For many applications, this life improvement may outweigh the initial capacity decrease.

  11. Performance of Hughes GaAs concentrator cells under 1-MeV electron irradiation

    International Nuclear Information System (INIS)

    Curtis, H.B.; Swartz, C.K.

    1985-01-01

    Several Hughes gallium arsenide (GaAs) concentrator cells were exposed to 1-MeV electrons at fluences up to 1x10 to the 15th power electrons/sq cm. Performance data were taken after several fluences, at two temperatures, and at concentration levels from 1 to approx. 150x AMO. Data at 1 sun and 25 deg C were taken with an X-25 xenon-lamp solar simulator. Data at concentration were taken using a pulsed solar simulator with the assumption of a linear relationship between short-circuit current and irradiance. The cells are 5 by 5 mm with a 4-mm diameter illuminated area. 1 reference

  12. Radiation performance of AlGaAs concentrator cells and expected performance of cascade structures

    International Nuclear Information System (INIS)

    Curtis, H.B.; Swartz, C.K.; Hart, R.E. Jr.

    1987-01-01

    Aluminum gallium arsenide, GaAs, silicon and InGaAs cells have been irradiated with 1 MeV electrons and 37 MeV protons. These cells are candidates for individual cells in a cascade structure. Data is presented for both electron and proton irradiation studies for one sun and a concentration level of 100X AMO. Results of calculations on the radiation resistance of cascade cell structures based on the individual cell data are also presented. Both series connected and separately connected structures are investigated

  13. Extracellular concentration of homocysteine in human cell lines is influenced by specific inhibitors of cyst(e)ine transport.

    Science.gov (United States)

    Hultberg, Björn

    2004-04-01

    Despite the growing evidence that plasma homocysteine is a cardiovascular risk factor, the mechanism behind the vascular injuries is still unknown. Studies of the cellular uptake systems for homocysteine are scarce, but membrane transporters of cyst(e)ine seem to be involved. In the present study the cellular uptake of extracellular homocysteine in HeLa and hepatoma cell lines is investigated by using several different transport inhibitors for cellular uptake of cyst(e)ine. It is shown that systems A and Xc- are the main transport systems for homocysteine uptake in HeLa cells. It is also confirmed that the magnitude of homocysteine uptake in hepatoma cells is lower than in HeLa cells. However, in the presence of high amounts of extracellular homocysteine both cell types exhibited a high elimination of homocysteine, which was inhibited by the presence of inhibitors of systems A or Xc-. It is possible that there is normally a high turnover of homocysteine in cell cultures, which is not detected by occasional determinations of homocysteine concentrations. The complex pattern of homocysteine production, release, uptake and distribution between different cells in the body is important to examine further in order to possibly be able to modulate the elimination of homocysteine from circulation and thereby lower the risk of cardiovascular disease.

  14. Detergent sclerosants at sub-lytic concentrations induce endothelial cell apoptosis through a caspase dependent pathway.

    Science.gov (United States)

    Cooley-Andrade, Osvaldo; Cheung, Kelvin; Chew, An-Ning; Connor, David Ewan; Parsi, Kurosh

    2016-07-01

    To investigate the apoptotic effects of detergent sclerosants sodium tetradecylsulphate (STS) and polidocanol (POL) on endothelial cells at sub-lytic concentrations. Human umbilical vein endothelial cells (HUVECs) were isolated and labelled with antibodies to assess for apoptosis and examined with confocal microscopy and flow cytometry. Isolated HUVECs viability was assessed using propidium iodide staining. Early apoptosis was determined by increased phosphatidylserine exposure by lactadherin binding. Caspase 3, 8, 9 and Bax activation as well as inhibitory assays with Pan Caspase (Z-VAD-FMK) and Bax (BI-6C9) were assessed to identify apoptotic pathways. Porimin activation was used to assess cell membrane permeability. Cell lysis reached almost 100 % with STS at 0.3 % and with POL at 0.6 %. Apoptosis was seen with both STS and POL at concentrations ranging from 0.075 to 0.15 %. PS exposure increased with both STS and POL and exhibited a dose-dependent trend. Active Caspase 3, 8 and 9 but not Bax were increased in HUVECs stimulated with low concentrations of both STS and POL. Inhibitory assays demonstrated Caspase 3, 8, 9 inhibition at low concentrations (0.075 to 0.6 %) with both STS and POL. Both agents increased the activation of porimin at all concentrations. Both sclerosants induced endothelial cell (EC) apoptosis at sub-lytic concentrations through a caspase-dependant pathway. Both agents induced EC oncosis.

  15. Translation in cell-free systems

    International Nuclear Information System (INIS)

    Jagus, R.

    1987-01-01

    The simplest, unambiguous identification of a particular mRNA is the identification of its protein product. This can be established by translation of the mRNA of interest in a cell-free protein-synthesizing system. Messenger RNA protein product identification is important in the isolation of a particular mRNA species for cDNA cloning and in the identification of positive cDNA clones. The two high-activity translation systems in common use are those prepared from rabbit reticulocytes and from wheat germ. Both systems are easy to prepare, and both are available commercially. Each has advantages and disadvantages over the other and a choice between the two will depend on the type of mRNAs to be translated, the prejudices of experience, and availability. The main disadvantage of the reticulocyte system is that it requires removal of endogenous mRNA. However, this is a relatively simple procedure. The wheat germ system does not require removal of endogenous mRNA and may translate weakly initiating mRNAs more efficiently. However, ionic optima for translation in the wheat germ system are more sensitive to the nature and concentration of mRNA and may need to be determined for each template. The biggest problem with the use of the wheat germ system is its tendency to produce incomplete translation products due to premature termination

  16. Vasopressin activates Akt/mTOR pathway in smooth muscle cells cultured in high glucose concentration

    Energy Technology Data Exchange (ETDEWEB)

    Montes, Daniela K.; Brenet, Marianne; Muñoz, Vanessa C.; Burgos, Patricia V.; Villanueva, Carolina I. [Department of Physiology, Universidad Austral de Chile, Valdivia 509-9200 (Chile); Figueroa, Carlos D. [Department of Anatomy, Histology and Pathology, Universidad Austral de Chile, Valdivia 509-9200 (Chile); González, Carlos B., E-mail: cbgonzal@uach.cl [Department of Physiology, Universidad Austral de Chile, Valdivia 509-9200 (Chile); Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, TX 77555 (United States)

    2013-11-29

    Highlights: •AVP induces mTOR phosphorylation in A-10 cells cultured in high glucose concentration. •The mTOR phosphorylation is mediated by the PI3K/Akt pathway activation. •The AVP-induced mTOR phosphorylation inhibited autophagy and stimulated cell proliferation. -- Abstract: Mammalian target of rapamycin (mTOR) complex is a key regulator of autophagy, cell growth and proliferation. Here, we studied the effects of arginine vasopressin (AVP) on mTOR activation in vascular smooth muscle cells cultured in high glucose concentration. AVP induced the mTOR phosphorylation in A-10 cells grown in high glucose, in contrast to cells cultured in normal glucose; wherein, only basal phosphorylation was observed. The AVP-induced mTOR phosphorylation was inhibited by a PI3K inhibitor. Moreover, the AVP-induced mTOR activation inhibited autophagy and increased thymidine incorporation in cells grown in high glucose. This increase was abolished by rapamycin which inhibits the mTORC1 complex formation. Our results suggest that AVP stimulates mTOR phosphorylation by activating the PI3K/Akt signaling pathway and, subsequently, inhibits autophagy and raises cell proliferation in A-10 cells maintained in high glucose concentration.

  17. Melanin-concentrating hormone: unique peptide neuronal systems in the rat brain and pituitary gland

    Energy Technology Data Exchange (ETDEWEB)

    Zamir, N.; Skofitsch, G.; Bannon, M.J.; Jacobowitz, D.M.

    1986-03-01

    A unique neuronal system was detected in the rat central nervous system by immunohistochemistry and radioimmunoassay with antibodies to salmon melanin-concentrating hormone (MCH). MCH-like immunoreactive (MCH-LI) cell bodies were confined to the hypothalamus. MCH-LI fibers were found throughout the brain but were most prevalent in hypothalamus, mesencephalon, and pons-medulla regions. High concentrations of MCH-LI were measured in the hypothalamic medial forebrain bundle (MFB), posterior hypothalamic nucleus, and nucleus of the diagonal band. Reversed-phase high-performance liquid chromatography of MFB extracts from rat brain indicate that MCH-like peptide from the rat has a different retention time than that of the salmon MCH. An osmotic stimuls (2% NaCl as drinking water for 120 hr) caused a marked increase in MCH-LI concentrations in the lateral hypothalamus and neurointermediate lobe. The present studies establish the presence of MCH-like peptide in the rat brain. The MCH-LI neuronal system is well situated to coordinate complex functions such as regulation of water intake.

  18. Electrical Rating of Concentrated Photovoltaic (CPV) Systems: Long-Term Performance Analysis and Comparison to Conventional PV Systems

    KAUST Repository

    Burhan, Muhammad

    2016-02-29

    The dynamic nature of meteorological data and the commercial availability of diverse photovoltaic systems, ranging from single-junction silicon-based PV panels to concentrated photovoltaic (CPV) systems utilizing multi-junction solar cells and a two-axis solar tracker, demand a simple but accurate methodology for energy planners and PV system designers to understand the economic feasibility of photovoltaic or renewable energy systems. In this paper, an electrical rating methodology is proposed that provides a common playing field for planners, consumers and PV manufacturers to evaluate the long-term performance of photovoltaic systems, as long-term electricity rating is deemed to be a quick and accurate method to evaluate economic viability and determine plant sizes and photovoltaic system power production. A long-term performance analysis based on monthly and electrical ratings (in kWh/m2/year) of two developed CPV prototypes, the Cassegrain mini dish and Fresnel lens CPVs with triple-junction solar cells operating under the meteorological conditions of Singapore, is presented in this paper. Performances are compared to other conventional photovoltaic systems.

  19. Estimating cell capacity for multi-cell electrical energy system

    Science.gov (United States)

    Hashemi, Iman Ahari

    A Multi-Cell Electrical Energy System is a set of batteries that are connected in series. The series batteries provide the required voltage necessary for the contraption. After using the energy that is provided by the batteries, some cells within the system tend to have a lower voltage than the other cells. Also, other factors, such as the number of times a battery has been charged or discharged, how long it has been within the system and many other factors, result in some cells having a lesser capacity compared to the other cells within the system. The outcome is that it lowers the required capacity that the electrical energy system is required to provide. By having an unknown cell capacity within the system, it is unknown how much of a charge can be provided to the system so that the cells are not overcharged or undercharged. Therefore, it is necessary to know the cells capacity within the system. Hence, if we were dealing with a single cell, the capacity could be obtained by a full charge and discharge of the cell. In a series system that contains multiple cells a full charging or discharging cannot happen as it might result in deteriorating the structure of some cells within the system. Hence, to find the capacity of a single cell within an electrical energy system it is required to obtain a method that can estimate the value of each cell within the electrical energy system. To approach this method an electrical energy system is required. The electrical energy system consists of rechargeable non-equal capacity batteries to provide the required energy to the system, a battery management system (BMS) board to monitor the cells voltages, an Arduino board that provides the required communication to BMS board, and the PC, and a software that is able to deliver the required data obtained from the Arduino board to the PC. The outcome, estimating the capacity of a cell within a multi-cell system, can be used in many battery related technologies to obtain unknown

  20. Effects of cell concentrations on the survival and repopulation of haemopoietic stem cells in irradiated bone marrow cell culture in vitro

    International Nuclear Information System (INIS)

    Fujitake, Hideki; Okamoto, Yuruko; Okubo, Hiroshi; Miyanomae, Takeshi; Kumagai, Keiko; Mori, K.J.

    1981-01-01

    Effects of cell concentrations on the survival and repopulation of haemopoietic stem cells after irradiation were studied in the long-term culture of mouse bone marrow cells in vitro. No difference was observed in the survival of the stem cells among cultures in which 0 - 10 7 cells were re-inoculated on the adherent cell colonies in the culture flask. Stem cells showed a significant proliferation within 1 week and the number of the stem cells exceeded the control in 3 weeks after irradiation in the cultures with less than 10 6 re-inoculated cells per flask. In contrast, there was a considerable delay in the onset of stem cell proliferation after irradiation in the culture with 10 7 cells per flask. Based on these results, a possibility that a stimulator of stem cell proliferation, released from irradiated stromal cells, is cancelled by an inhibitory factor produced by irradiated or unirradiated haemopoietic cells is postulated. (author)

  1. KOH concentration effect on cycle life of nickel-hydrogen cells. III - Cycle life test

    Science.gov (United States)

    Lim, H. S.; Verzwyvelt, S. A.

    1988-01-01

    A cycle life test of Ni/H2 cells containing electrolytes of various KOH concentrations and a sintered type nickel electrode was carried out at 23 C using a 45 min accelerated low earth orbit (LEO) cycle regime at 80 percent depth of discharge. One of three cells containing 26 percent KOH has achieved over 28,000 cycles, and the other two 19,000 cycles, without a sign of failure. Two other cells containing 31 percent KOH electrolyte, which is the concentration presently used in aerospace cells, failed after 2,979 and 3,620 cycles. This result indicates that the cycle life of the present type of Ni/H2 cells may be extended by a factor of 5 to 10 simply by lowering the KOH concentration. Long cycle life of a Ni/H2 battery at high depth-of-discharge operation is desired, particularly for an LEO spacecraft application. Typically, battery life of about 30,000 cycles is required for a five year mission in an LEO. Such a cycle life with presently available cells can be assured only at a very low depth-of-discharge operation. Results of testing already show that the cycle life of an Ni/H2 cell is tremendously improved by simply using an electrolyte of low KOH concentration.

  2. KOH concentration effect on cycle life of nickel-hydrogen cells

    Science.gov (United States)

    Lim, Hong S.; Verzwyvelt, S. A.

    1987-01-01

    A cycle life test of Ni/H2 cells containing electrolytes of various KOH concentrations and a sintered type nickel electrode was carried out at 23 C using a 45 min accelerated low Earth orbit (LEO) cycle regime at 80 percent depth of discharge. One of three cells containing 26 percent KOH has achieved over 28,000 cycles, and the other two 19,000 cycles, without a sign of failure. Two other cells containing 31 percent KOH electrolyte, which is the concentration presently used in aerospace cells, failed after 2,979 and 3,620 cycles. This result indicates that the cycle life of the present type of Ni/H2 cells may be extended by a factor of 5 to 10 simply by lowering the KOH concentration. Long cycle life of a Ni/H2 battery at high depth-of-discharge operation is desired, particularly for an LEO spacecraft application. Typically, battery life of about 30,000 cycles is required for a five year mission in an LEO. Such a cycle life with presently available cells can be assured only at a very low depth-of-discharge operation. Results of testing already show that the cycle life of an Ni/H2 cell is tremendously improved by simply using an electrolyte of low KOH concentration.

  3. Fuel-cell engine stream conditioning system

    Science.gov (United States)

    DuBose, Ronald Arthur

    2002-01-01

    A stream conditioning system for a fuel cell gas management system or fuel cell engine. The stream conditioning system manages species potential in at least one fuel cell reactant stream. A species transfer device is located in the path of at least one reactant stream of a fuel cell's inlet or outlet, which transfer device conditions that stream to improve the efficiency of the fuel cell. The species transfer device incorporates an exchange media and a sorbent. The fuel cell gas management system can include a cathode loop with the stream conditioning system transferring latent and sensible heat from an exhaust stream to the cathode inlet stream of the fuel cell; an anode humidity retention system for maintaining the total enthalpy of the anode stream exiting the fuel cell related to the total enthalpy of the anode inlet stream; and a cooling water management system having segregated deionized water and cooling water loops interconnected by means of a brazed plate heat exchanger.

  4. Electrical and Thermal Performance Analysis for a Highly Concentrating Photovoltaic/Thermal System

    Directory of Open Access Journals (Sweden)

    Ning Xu

    2015-01-01

    Full Text Available A 30 kW highly concentrating photovoltaic/thermal (HCPV/T system has been constructed and tested outdoors. The HCPV/T system consists of 32 modules, each of which consists of point-focus Fresnel lens and triple-junction solar cells with a geometric concentrating ratio of 1090x. The modules are connected to produce both electrical and thermal energy. Performance analysis has been conducted from the viewpoint of thermodynamics. The experimental results show that highest photovoltaic efficiency of 30% and instantaneous thermal efficiency of 30% can be achieved at the same time, which means the total solar energy conversion efficiency of the HCPV/T system is higher than 60%. The photovoltaic efficiency increases with direct irradiance when the direct irradiance is below 580 W/m2, but it remains nearly unchanged when the direct irradiation is higher than 580 W/m2. The instantaneous thermal efficiency decreases during water heating process. However, the electrical performance of the system is not affected obviously by water temperature. Highest exergetic efficiency of 35.4% can be produced by the HCPV/T system. The exergetic efficiency is mainly affected by irradiation level, which is similar to the characteristics of photovoltaic performance.

  5. Stomatal and pavement cell density linked to leaf internal CO2 concentration

    Science.gov (United States)

    Šantrůček, Jiří; Vráblová, Martina; Šimková, Marie; Hronková, Marie; Drtinová, Martina; Květoň, Jiří; Vrábl, Daniel; Kubásek, Jiří; Macková, Jana; Wiesnerová, Dana; Neuwithová, Jitka; Schreiber, Lukas

    2014-01-01

    Background and Aims Stomatal density (SD) generally decreases with rising atmospheric CO2 concentration, Ca. However, SD is also affected by light, air humidity and drought, all under systemic signalling from older leaves. This makes our understanding of how Ca controls SD incomplete. This study tested the hypotheses that SD is affected by the internal CO2 concentration of the leaf, Ci, rather than Ca, and that cotyledons, as the first plant assimilation organs, lack the systemic signal. Methods Sunflower (Helianthus annuus), beech (Fagus sylvatica), arabidopsis (Arabidopsis thaliana) and garden cress (Lepidium sativum) were grown under contrasting environmental conditions that affected Ci while Ca was kept constant. The SD, pavement cell density (PCD) and stomatal index (SI) responses to Ci in cotyledons and the first leaves of garden cress were compared. 13C abundance (δ13C) in leaf dry matter was used to estimate the effective Ci during leaf development. The SD was estimated from leaf imprints. Key Results SD correlated negatively with Ci in leaves of all four species and under three different treatments (irradiance, abscisic acid and osmotic stress). PCD in arabidopsis and garden cress responded similarly, so that SI was largely unaffected. However, SD and PCD of cotyledons were insensitive to Ci, indicating an essential role for systemic signalling. Conclusions It is proposed that Ci or a Ci-linked factor plays an important role in modulating SD and PCD during epidermis development and leaf expansion. The absence of a Ci–SD relationship in the cotyledons of garden cress indicates the key role of lower-insertion CO2 assimilation organs in signal perception and its long-distance transport. PMID:24825295

  6. Evaluation of optimal dual axis concentrated photovoltaic thermal system with active ventilation using Frog Leap algorithm

    International Nuclear Information System (INIS)

    Gholami, H.; Sarwat, A.I.; Hosseinian, H.; Khalilnejad, A.

    2015-01-01

    Highlights: • Electro-thermal performance of open-loop controlled dual axis CPVT is investigated. • For using the absorbed heat, active ventilation with a heat storage tank is used. • Economic optimization of the system is performed, using Frog Leap algorithm. • Detailed model of all sections is simulated with their characteristics evaluation. • Triple-junction photovoltaic cells, which are the most recent technology, are used. - Abstract: In this study, design and optimization of a concentrated photovoltaic thermal (CPVT) system considering electrical, mechanical, and economical aspects is investigated. For this purpose, each section of the system is simulated in MATLAB, in detail. Triple-junction photovoltaic cells, which are the most recent technology, are used in this study. They are more efficient in comparison to conventional photovoltaic cells. Unlike ordinary procedures, in this work active ventilation is used for absorbing the thermal power of radiation, using heat storage tanks, which not only results in increasing the electrical efficiency of the system through decreasing the temperature, but also leads to storing and managing produced thermal energy and increasing the total efficiency of the system up to 85 percent. The operation of the CPVT system is investigated for total hours of the year, considering the needed thermal load, meteorological conditions, and hourly radiation of Khuznin, a city in Qazvin province, Iran. Finally, the collector used for this system is optimized economically, using frog leap algorithm, which resulted in the cost of 13.4 $/m 2 for a collector with the optimal distance between tubes of 6.34 cm.

  7. High Concentration of Melatonin Regulates Leaf Development by Suppressing Cell Proliferation and Endoreduplication in Arabidopsis.

    Science.gov (United States)

    Wang, Qiannan; An, Bang; Shi, Haitao; Luo, Hongli; He, Chaozu

    2017-05-05

    N -acetyl-5-methoxytryptamine (Melatonin), as a crucial messenger in plants, functions in adjusting biological rhythms, stress tolerance, plant growth and development. Several studies have shown the retardation effect of exogenous melatonin treatment on plant growth and development. However, the in vivo role of melatonin in regulating plant leaf growth and the underlying mechanism are still unclear. In this study, we found that high concentration of melatonin suppressed leaf growth in Arabidopsis by reducing both cell size and cell number. Further kinetic analysis of the fifth leaves showed that melatonin remarkably inhibited cell division rate. Additionally, flow cytometic analysis indicated that melatonin negatively regulated endoreduplication during leaf development. Consistently, the expression analysis revealed that melatonin regulated the transcriptional levels of key genes of cell cycle and ribosome. Taken together, this study suggests that high concentration of melatonin negatively regulated the leaf growth and development in Arabidopsis , through modulation of endoreduplication and the transcripts of cell cycle and ribosomal key genes.

  8. Silver nanoparticles promote osteogenic differentiation of human urine-derived stem cells at noncytotoxic concentrations

    Directory of Open Access Journals (Sweden)

    Qin H

    2014-05-01

    Full Text Available Hui Qin,1,* Chen Zhu,2,* Zhiquan An,1 Yao Jiang,1 Yaochao Zhao,1 Jiaxin Wang,1 Xin Liu,1 Bing Hui,1 Xianlong Zhang,1 Yang Wang1 1Department of Orthopedics, Sixth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 2Department of Orthopaedic Surgery, Provincial Hospital Affiliated to Anhui Medical University, HeFei, People's Republic of China *These authors contributed equally to this work Abstract: In tissue engineering, urine-derived stem cells are ideal seed cells and silver nanoparticles (AgNPs are perfect antimicrobial agents. Due to a distinct lack of information on the effects of AgNPs on urine-derived stem cells, a study was conducted to evaluate the effects of silver ions and AgNPs upon the cytotoxicity and osteogenic differentiation of urine-derived stem cells. Initially, AgNPs or AgNO3 were exposed to urine-derived stem cells for 24 hours. Cytotoxicity was measured using the Cell Counting kit-8 (CCK-8 test. The effects of AgNPs or AgNO3 at the maximum safety concentration determined by the CCK-8 test on osteogenic differentiation of urine-derived stem cells were assessed by alkaline phosphatase activity, Alizarin Red S staining, and the quantitative reverse transcription polymerase chain reaction. Lastly, the effects of AgNPs or AgNO3 on "urine-derived stem cell actin cytoskeleton organization" and RhoA activity were assessed by rhodamine-phalloidin staining and Western blotting. Concentration-dependent toxicity was observed starting at an AgNO3 concentration of 2 µg/mL and at an AgNP concentration of 4 µg/mL. At these concentrations, AgNPs were observed to promote osteogenic differentiation of urine-derived stem cells, induce actin polymerization and increase cytoskeletal tension, and activate RhoA; AgNO3 had no such effects. In conclusion, AgNPs can promote osteogenic differentiation of urine-derived stem cells at a suitable concentration, independently of silver ions, and are suitable for incorporation

  9. Sublethal Concentrations of Carbapenems Alter Cell Morphology and Genomic Expression of Klebsiella pneumoniae Biofilms

    Science.gov (United States)

    Van Laar, Tricia A.; Chen, Tsute; You, Tao

    2015-01-01

    Klebsiella pneumoniae, a Gram-negative bacterium, is normally associated with pneumonia in patients with weakened immune systems. However, it is also a prevalent nosocomial infectious agent that can be found in infected surgical sites and combat wounds. Many of these clinical strains display multidrug resistance. We have worked with a clinical strain of K. pneumoniae that was initially isolated from a wound of an injured soldier. This strain demonstrated resistance to many commonly used antibiotics but sensitivity to carbapenems. This isolate was capable of forming biofilms in vitro, contributing to its increased antibiotic resistance and impaired clearance. We were interested in determining how sublethal concentrations of carbapenem treatment specifically affect K. pneumoniae biofilms both in morphology and in genomic expression. Scanning electron microscopy showed striking morphological differences between untreated and treated biofilms, including rounding, blebbing, and dimpling of treated cells. Comparative transcriptome analysis using RNA sequencing (RNA-Seq) technology identified a large number of open reading frames (ORFs) differentially regulated in response to carbapenem treatment at 2 and 24 h. ORFs upregulated with carbapenem treatment included genes involved in resistance, as well as those coding for antiporters and autoinducers. ORFs downregulated included those coding for metal transporters, membrane biosynthesis proteins, and motility proteins. Quantitative real-time PCR validated the general trend of some of these differentially regulated ORFs. Treatment of K. pneumoniae biofilms with sublethal concentrations of carbapenems induced a wide range of phenotypic and gene expression changes. This study reveals some of the mechanisms underlying how sublethal amounts of carbapenems could affect the overall fitness and pathogenic potential of K. pneumoniae biofilm cells. PMID:25583711

  10. The application of pulsed concentrated solar radiation with the purpose of immune system correction of rheumatic arthritis patients

    International Nuclear Information System (INIS)

    Shonazarov, N.P.

    1996-01-01

    The investigation results of dosed pulsed concentrated solar radiation(PCSR) influence to rheumatic arthritis patients are given. It was obtained that PCSR especially in the complex with balneological physiotherapy factors corrects regulator functions of cell link and decreases the density of humoral link of immune system. (author). 2 refs., 2 tabs

  11. Extension of the anisotropic biphasic theory to large strain and high cell concentrations

    Science.gov (United States)

    Evans, Michael Charles

    The fiber alignment of engineered tissues is an important design criterion for engineered tissues. The fiber alignment can affect the material properties as well as the behavior of the material. The Anisotropic Biphasic Theory (ABT) has been solved previously in two dimensions for axisymmetric problems such as disks and tubes. We solved the ABT in three dimensions for the first time and used the results from the ABT to determine fiber alignments in various tissue equivalent structures. The framework that the ABT was solved in, called Trellis, has the capability of h and r adaptivity allowing accurate solutions with coarse initial meshes. Several cases were studied to validate the method and were then compared to previously published experiments. The effect of complex constraints on the final fiber alignment was studied. The initial geometry has a dramatic effect on the final fiber alignment for such simple shapes as tissue engineered flaps and cruciforms. The constraints on the gel can affect the fiber alignment throughout the gel. In order to model more complex geometries, such as the bioartificial heart valve, an additional boundary condition was added to our three dimensional formulation. A penalty method was used on the force balance of the ABT to mimic a slippery surface found on a Teflon mandrel. The new boundary condition was used to model the bioartificial heart valve; the alignment generated was similar to that found experimentally. In order to determine high strain and large cell concentration behavior of collagen gels, a series of experiments was developed to determine material properties after incubation. The cell concentration and collagen concentration was varied and the material properties were measured at several different time points. The tensile material properties were found to increase with both collagen and cell concentration. The compaction ratio was found to increase with cell concentration and time, but decrease with collagen concentration

  12. Low-Cost High-Concentration Photovoltaic Systems for Utility Power Generation

    Energy Technology Data Exchange (ETDEWEB)

    McConnell, R.; Garboushian, V.; Gordon, R.; Dutra, D.; Kinsey, G.; Geer, S.; Gomez, H.; Cameron, C.

    2012-03-31

    Under DOE's Technology Pathway Partnership (TPP) program, Amonix, Inc. developed a new generation of high-concentration photovoltaic systems using multijunction technology and established the manufacturing capacity needed to supply multi-megawatt power plants buing using the new Amonix 7700-series solar energy systems. For this effort, Amonix Collaborated with a variety of suppliers and partners to complete project tasks. Subcontractors included: Evonik/Cyro; Hitek; the National Renewable Energy Laboratory (NREL); Raytech; Spectrolab; UL; University of Nevada, Las Vegas; and TUV Rheinland PTL. The Amonix TPP tasks included: Task 1: Multijunction Cell Optimization for Field Operation, Task 2: Fresnel Lens R&D, Task 3: Cell Package Design & Production, Task 4: Standards Compliance and Reliability Testing, Task 5: Receiver Plate Production, Task 6: MegaModule Performance, Task 7: MegaModule Cost Reduction, Task 8: Factory Setup and MegaModule Production, Task 9: Tracker and Tracking Controller, Task 10: Installation and Balance of System (BOS), Task 11: Field Testing, and Task 12: Solar Advisor Modeling and Market Analysis. Amonix's TPP addressed nearly the complete PV value chain from epitaxial layer design and wafer processing through system design, manufacturing, deployment and O&M. Amonix has made progress toward achieving these reduced costs through the development of its 28%+ efficient MegaModule, reduced manufacturing and installation cost through design for manufacturing and assembly, automated manufacturing processes, and reduced O&M costs. Program highlights include: (1) Optimized multijunction cell and cell package design to improve performance by > 10%; (2) Updated lens design provided 7% increased performance and higher concentration; (3) 28.7% DC STC MegaModule efficiency achieved in Phase II exceeded Phase III performance goal; (4) New 16' focal length MegaModule achieved target materials and manufacturing cost reduction; (5) Designed and

  13. Production of glucose syrups in highly concentrated systems

    NARCIS (Netherlands)

    Veen, van der M.E.; Goot, van der A.J.; Boom, R.M.

    2005-01-01

    We have investigated the hydrolysis of maltodextrins in a high concentration (up to 70%), by means of enzymatic and acid catalysis. The study revealed that the equilibrium compositions of the catalyzed reactions were kinetically determined by the selectivity of the catalyst, the substrate

  14. Hydrodynamic instabilities and concentration polarization coupled by osmotic pressure in a Taylor-Couette cell

    Science.gov (United States)

    Martinand, Denis; Tilton, Nils

    2016-11-01

    This study addresses analytically and numerically the coupling between hydrodynamic instabilities and osmotic pressure driven by concentration polarization. The configuration consists of a Taylor-Couette cell filled with a Newtonian fluid carrying a passive scalar. Whereas the concentric inner and outer cylinders are membranes permeable to the solvent, they totally reject the scalar. As a radial in- or outflow of solvent is imposed through both cylinders, a concentration boundary layer develops on the cylinder where the solvent exits, until an equilibrium steady state is reached. In addition, the rotation of the inner cylinder is used to drive centrifugal instabilities in the form of toroidal vortices, which interact with the concentration boundary layer. By means of the osmotic pressure, concentration polarization is found to promote or hinder the hydrodynamic instabilities, depending on capacity of the vortices and diffusion to increase the concentration field at the membrane. The results obtained by analytical stability analysis agree with dedicated Direct Numerical Simulations.

  15. Multi-Generation Concentrating Solar-Hydrogen Power System for Sustainable Rural Development

    Energy Technology Data Exchange (ETDEWEB)

    Krothapalli, A.; Greska, B.

    2007-07-01

    This paper describes an energy system that is designed to meet the demands of rural populations that currently have no access to grid-connected electricity. Besides electricity, it is well recognized that rural populations need at least a centralized refrigeration system for storage of medicines and other emergency supplies, as well as safe drinking water. Here we propose a district system that will employ a multi-generation concentrated solar power (CSP) system that will generate electricity and supply the heat needed for both absorption refrigeration and membrane distillation (MD) water purification. The electricity will be used to generate hydrogen through highly efficient water electrolysis and individual households can use the hydrogen for generating electricity, via affordable proton exchange membrane (PEM) fuel cells, and as a fuel for cooking. The multi-generation system is being developed such that its components will be easy to manufacture and maintain. As a result, these components will be less efficient than their typical counterparts but their low cost-to-efficiency ratio will allow for us to meet our installation cost goal of $1/Watt for the entire system. The objective of this paper is to introduce the system concept and discuss the system components that are currently under development. (auth)

  16. Different concentrations of kaempferol distinctly modulate murine embryonic stem cell function.

    Science.gov (United States)

    Correia, Marcelo; Rodrigues, Ana S; Perestrelo, Tânia; Pereira, Sandro L; Ribeiro, Marcelo F; Sousa, Maria I; Ramalho-Santos, João

    2016-01-01

    Kaempferol (3,4',5,7-tetrahydroxyflavone) is a natural flavonoid with several beneficial and protective effects. It has been demonstrated that kaempferol has anticancer properties, particularly due to its effects on proliferation, apoptosis and the cell cycle. However, possible effects on pluripotent embryonic stem cell function have not yet been addressed. Embryonic stem cells have the ability to self-renew and to differentiate into all three germ layers with potential applications in regenerative medicine and in vitro toxicology. We show that exposure of murine embryonic stem cells (mESC) to high concentrations of kaempferol (200 μM) leads to decreased cell numbers, although the resulting smaller cell colonies remain pluripotent. However, lower concentrations of this compound (20 μM) increase the expression of pluripotency markers in mESCs. Mitochondrial membrane potential and mitochondrial mass are not affected, but a dose-dependent increase in apoptosis takes place. Moreover, mESC differentiation is impaired by kaempferol, which was not related to apoptosis induction. Our results show that low concentrations of kaempferol can be beneficial for pluripotency, but inhibit proper differentiation of mESCs. Additionally, high concentrations induce apoptosis and increase mitochondrial reactive oxygen species (ROS). Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. N-myc oncogene amplification is correlated to trace metal concentrations in neuroblastoma cultured cells

    International Nuclear Information System (INIS)

    Gouget, B.; Sergeant, C.; Benard, J.; Llabador, Y.; Simonoff, M.

    2000-01-01

    N-myc oncogene amplification is a powerful predictor of aggressive behavior of neuroblastoma (NB), the most common solid tumor of the early childhood. Since N-myc overexpression - subsequent to amplification - determines a phenotype of invasiveness and metastatic spreading, it is assumed that N-myc amplified neuroblasts synthesize zinc metalloenzymes leading to tumor invasion and formation of metastases. In order to test a possible relation between N-myc oncogene amplification and trace metal contents in human NB cells, Fe, Cu and Zn concentrations have been measured by nuclear microprobe analysis in three human neuroblastoma cell lines with various degrees of N-myc amplification. Elemental determinations show uniform distribution of trace metals within the cells, but variations of intracellular trace metal concentrations with respect to the degree of N-myc amplification are highly dependent on the nature of the element. Zinc concentration is higher in both N-myc amplified cell lines (IMR-32 and IGR-N-91) than in the non-amplified cells (SK-N-SH). In contrast, intracellular iron content is particularly low in N-myc amplified cell lines. Moreover, copper concentrations showed an increase with the degree of N-myc amplification. These results indicate that a relationship exists between intracellular trace metals and N-myc oncogene amplification. They further suggest that trace metals very probably play a determinant role in mechanisms of the neuroblastoma invasiveness

  18. N- myc oncogene amplification is correlated to trace metal concentrations in neuroblastoma cultured cells

    Science.gov (United States)

    Gouget, B.; Sergeant, C.; Benard, J.; Llabador, Y.; Simonoff, M.

    2000-10-01

    N- myc oncogene amplification is a powerful predictor of aggressive behavior of neuroblastoma (NB), the most common solid tumor of the early childhood. Since N- myc overexpression - subsequent to amplification - determines a phenotype of invasiveness and metastatic spreading, it is assumed that N- myc amplified neuroblasts synthesize zinc metalloenzymes leading to tumor invasion and formation of metastases. In order to test a possible relation between N- myc oncogene amplification and trace metal contents in human NB cells, Fe, Cu and Zn concentrations have been measured by nuclear microprobe analysis in three human neuroblastoma cell lines with various degrees of N- myc amplification. Elemental determinations show uniform distribution of trace metals within the cells, but variations of intracellular trace metal concentrations with respect to the degree of N- myc amplification are highly dependent on the nature of the element. Zinc concentration is higher in both N- myc amplified cell lines (IMR-32 and IGR-N-91) than in the non-amplified cells (SK-N-SH). In contrast, intracellular iron content is particularly low in N- myc amplified cell lines. Moreover, copper concentrations showed an increase with the degree of N- myc amplification. These results indicate that a relationship exists between intracellular trace metals and N- myc oncogene amplification. They further suggest that trace metals very probably play a determinant role in mechanisms of the neuroblastoma invasiveness.

  19. Battery Cell Balancing System and Method

    Science.gov (United States)

    Davies, Francis J. (Inventor)

    2014-01-01

    A battery cell balancing system is operable to utilize a relatively small number of transformers interconnected with a battery having a plurality of battery cells to selectively charge the battery cells. Windings of the transformers are simultaneously driven with a plurality of waveforms whereupon selected battery cells or groups of cells are selected and charged. A transformer drive circuit is operable to selectively vary the waveforms to thereby vary a weighted voltage associated with each of the battery cells.

  20. Solar cells: Operating principles, technology, and system applications

    Science.gov (United States)

    Green, M. A.

    Solar cell theory, materials, fabrication, design, modules, and systems are discussed. The solar source of light energy is described and quantified, along with a review of semiconductor properties and the generation, recombination, and the basic equations of photovoltaic device physics. Particular attention is given to p-n junction diodes, including efficiency limits, losses, and measurements. Si solar cell technology is described for the production of solar-quality crystals and wafers, and design, improvements, and device structures are examined. Consideration is given to alternate semiconductor materials and applications in concentrating systems, storage, and the design and construction of stand-alone systems and systems for residential and centralized power generation.

  1. Effects of sub-toxic concentrations of camphorquinone on cell lipid metabolism.

    Science.gov (United States)

    Datar, Rahul A; Rueggeberg, Fredrick A; Caughman, Gretchen B; Wataha, John C; Lewis, Jill B; Schuster, George S

    2005-01-01

    The biological effects of camphorquinone (CQ), an initiator for light-polymerized resins, have been reported to relate to its ability to generate free radicals and cause radical-induced membrane damage via lipid peroxidation. However, the effects of CQ on lipids other than peroxidation may result in unfavorable tissue responses especially at concentrations that are not overtly toxic to cells. The purpose of the current study was to examine the effects of CQ on cell lipid metabolism at subtoxic concentrations, with or without visible light irradiation. HCP and THP-1 cells were exposed to CQ with or without light irradiation under clinically relevant conditions and lipid metabolism was analyzed using 14C-labeling and thin-layer chromatography. We found that CQ increased synthesis of neutral lipids, such as triglycerides, from 7 to nearly 15% of the total and diglycerides from 2% to about 3% of the total in HCP cells, while synthesis of phospholipids, such as sphingomyelin, was decreased by 1-1.5%. In THP-1 cells cholesterol synthesis increased more than 2-fold and cholesterol ester synthesis increased more than 5-fold. Light-activated CQ did not differ significantly in terms of its bioactivity compared to no-light conditions. We conclude that CQ significantly altered the metabolism of several important structural lipids in two cell types at sub-toxic concentrations that are clinically relevant. These changes in lipid metabolism may in turn affect membrane integrity and permeability and possibly lead to significant changes in cell responses.

  2. Modular PEM Fuel Cell SCADA & Simulator System

    Directory of Open Access Journals (Sweden)

    Francisca Segura

    2015-09-01

    Full Text Available The paper presents a Supervision, Control, Data Acquisition and Simulation (SCADA & Simulator system that allows for real-time training in the actual operation of a modular PEM fuel cell system. This SCADA & Simulator system consists of a free software tool that operates in real time and simulates real situations like failures and breakdowns in the system. This developed SCADA & Simulator system allows us to properly operate a fuel cell and helps us to understand how fuel cells operate and what devices are needed to configure and run the fuel cells, from the individual stack up to the whole fuel cell system. The SCADA & Simulator system governs a modular system integrated by three PEM fuel cells achieving power rates higher than tens of kilowatts.

  3. The prognostic value of YKL-40 concentrations in nonmyeloablative conditioning allogeneic hematopoietic cell transplantation

    DEFF Research Database (Denmark)

    Mørup, Anne Mette; Kornblit, Brian; Johansen, Julia S

    2011-01-01

    and plasma YKL-40 concentrations as prognostic biomarkers in a cohort of 149 patients treated with hematopoietic cell transplantation (HCT) after nonmyeloablative conditioning for hematologic malignancies. Recipients with pretransplant YKL-40 concentrations above the age-adjusted 95th percentile (high) had...... could function as a biomarker for relapse risk and treatment-related toxicity, and possibly as a tool complementing clinical risk scores such as the HCT comorbidity index....

  4. The effects of a reduced environmental deuterium concentration on growth of culture normal and neoplastic cells

    International Nuclear Information System (INIS)

    Bild, Walther; Haulica, Ion; Nastasa, V.

    2002-01-01

    In connection with studies on the effects of deuterium depleted water on radioprotection and immunostimulation, research was conducted to find out effects of environmental depleted deuterium upon culture cells growth. The reduction of deuterium concentration in cellular medium was achieved by forming the culture medium for RMPI 1640, Gibco BRL cells with under-deuterated water (produced at ICSI) with different deuterium concentration (30, 60, 90, 120 ppm), as compared with control batches in the same medium constituted from normal distilled water (145-150 ppm D/(D+H). A significant stimulation in the cellular growth due to deuterium depletion in the culture media was observed. Also, variations in growth rates and the profile of proliferation curves in neoplastic cells as compared with normal cells were observed, the same trend being observed in all cultures. Paradoxically, quantitative effects were observed, peaking at 90 ppm deuterium concentration rather than at a minimal concentration, as expected. The MTT test confirmed the stimulating effects of deuterium depletion. To put into evidence the immunity stimulation, the explant rat splenocytes from laboratory animals were grown, stimulated with Concanavaline A or bacterial Lipopolysaccharides of increasing concentration. Similar effects were observed

  5. Chip based electroanalytical systems for cell analysis

    DEFF Research Database (Denmark)

    Spegel, C.; Heiskanen, A.; Skjolding, L.H.D.

    2008-01-01

    ' measurements of processes related to living cells, i.e., systems without lysing the cells. The focus is on chip based amperometric and impedimetric cell analysis systems where measurements utilizing solely carbon fiber microelectrodes (CFME) and other nonchip electrode formats, such as CFME for exocytosis...

  6. A Fresnel lenses based concentrated PV system in a greenhouse

    NARCIS (Netherlands)

    Sonneveld, P.J.; Swinkels, G.L.A.M.; Tuijl, van B.A.J.; Janssen, H.J.J.; Gieling, T.H.

    2011-01-01

    The scope of this investigation is the development and testing of a new type of greenhouse with an integrated linear Fresnel lens, receiver module and an innovative system for tracking to exploit all direct radiation in a solar energy system. The basic idea of this horticultural application is to

  7. Study official non- concentration system benefits by emphasize to ...

    African Journals Online (AJOL)

    The huge volume of government services through various government departments, so having a coherent administrative system, efficient, transparent and accountable government and policy makers always a problem for any society is considered. In administrative law, govern the country with two systems will be common in ...

  8. Performance investigation of low – Concentration photovoltaic systems under hot and arid conditions: Experimental and numerical results

    International Nuclear Information System (INIS)

    Yousef, Mohamed S.; Abdel Rahman, Ali K.; Ookawara, S.

    2016-01-01

    Highlights: • Influence of cooling on the performance of photovoltaic systems. • A comprehensive model (optical, thermal, and electrical) was developed. • Experimental measurements were conducted under hot climate conditions. • For conventional photovoltaic with cooling, about 11% more power was obtained. • For concentrated photovoltaic with cooling, about 15% more power was obtained. - Abstract: In this study, a comparative performance analysis was performed between a conventional photovoltaic system and a low-concentration photovoltaic system. Two typical photovoltaic modules and two compound parabolic concentrating photovoltaic systems were examined. A Cooling system was employed to lower the temperature of the solar cells in each of the two configurations. Experimental and numerical investigations of the performance of the two arrangements with and without cooling were presented. Experiments were conducted outdoors at the Egypt-Japan University of Science and Technology, subjected to the hot climate conditions of New Borg El-Arab City, Alexandria, Egypt (Longitude/Latitude: E 029°42′/N 30°55′). A comprehensive system model was established, which comprises an optical model, coupled with thermal and electrical models. The coupled model was developed analytically and solved numerically, using MATLAB software, to assess the overall performance of the two configurations, considering the concentration ratio of the concentrated photovoltaic system to be 2.4X. The results indicated that cooling the solar panels considerably improved the electrical power yield of the photovoltaic systems. By employing cooling, the temperatures of the conventional photovoltaic system and the concentrated photovoltaic system were effectively lowered by approximately 25% and 30%, respectively, resulting in a significant enhancement in the electrical power output of the photovoltaic system by 11% and that of the concentrated photovoltaic system by 15%. Furthermore, the

  9. Sponge phase behaviour in concentrated surfactant-alcohol-brine system

    Science.gov (United States)

    Gomati, R.; Daoud, M.; Gharbi, A.

    1997-02-01

    The sponge phase monodomain extending from the brine corner to the alcohol corner of an ionic surfactant-alcohol-brine phase diagram is first detailed and then investigated by electrolytic conductivity and refractive index measurements. Upon progressive dimunition of the brine fraction of the sponge phase, the ionic conductivity suffers from two gumps corresponding to two respective critical concentrations, while the variation of the refractive index remains linear but exhibits two slope changes. According to the phase diagram observations we propose one scenario, in agreement with theoretical predictions, to explain these results in terms of continuous structural transformations of the amphiphilic membrane from the swollen sponge phase to the inverse micellar phase.

  10. Space Photovoltaic Concentrator Using Robust Fresnel Lenses, 4-Junction Cells, Graphene Radiators, and Articulating Receivers

    Science.gov (United States)

    O'Neill, Mark; McDanal, A. J.; Brandhorst, Henry; Spence, Brian; Iqbal, Shawn; Sharps, Paul; McPheeters, Clay; Steinfeldt, Jeff; Piszczor, Michael; Myers, Matt

    2016-01-01

    At the 42nd PVSC, our team presented recent advances in our space photovoltaic concentrator technology. These advances include more robust Fresnel lenses for optical concentration, more thermally conductive graphene radiators for waste heat rejection, improved color-mixing lens technology to minimize chromatic aberration losses with 4-junction solar cells, and an articulating photovoltaic receiver enabling single-axis sun-tracking, while maintaining a sharp focal line despite large beta angles of incidence. In the past year, under a NASA Phase II SBIR program, our team has made much additional progress in the development of this new space photovoltaic concentrator technology, as described in this paper.

  11. Methods to homogenize electrochemical concentration cell (ECC) ozonesonde measurements across changes in sensing solution concentration or ozonesonde manufacturer

    Science.gov (United States)

    Deshler, Terry; Stübi, Rene; Schmidlin, Francis J.; Mercer, Jennifer L.; Smit, Herman G. J.; Johnson, Bryan J.; Kivi, Rigel; Nardi, Bruno

    2017-06-01

    Ozone plays a significant role in the chemical and radiative state of the atmosphere. For this reason there are many instruments used to measure ozone from the ground, from space, and from balloons. Balloon-borne electrochemical cell ozonesondes provide some of the best measurements of the ozone profile up to the mid-stratosphere, providing high vertical resolution, high precision, and a wide geographic distribution. From the mid-1990s to the late 2000s the consistency of long-term records from balloon-borne ozonesondes has been compromised by differences in manufacturers, Science Pump (SP) and ENSCI (EN), and differences in recommended sensor solution concentrations, 1.0 % potassium iodide (KI) and the one-half dilution: 0.5 %. To investigate these differences, a number of organizations have independently undertaken comparisons of the various ozonesonde types and solution concentrations, resulting in 197 ozonesonde comparison profiles. The goal of this study is to derive transfer functions to allow measurements outside of standard recommendations, for sensor composition and ozonesonde type, to be converted to a standard measurement and thus homogenize the data to the expected accuracy of 5 % (10 %) in the stratosphere (troposphere). Subsets of these data have been analyzed previously and intermediate transfer functions derived. Here all the comparison data are analyzed to compare (1) differences in sensor solution composition for a single ozonesonde type, (2) differences in ozonesonde type for a single sensor solution composition, and (3) the World Meteorological Organization's (WMO) and manufacturers' recommendations of 1.0 % KI solution for Science Pump and 0.5 % KI for ENSCI. From the recommendations it is clear that ENSCI ozonesondes and 1.0 % KI solution result in higher amounts of ozone sensed. The results indicate that differences in solution composition and in ozonesonde type display little pressure dependence at pressures ≥ 30 hPa, and thus the transfer

  12. Methods to homogenize electrochemical concentration cell (ECC ozonesonde measurements across changes in sensing solution concentration or ozonesonde manufacturer

    Directory of Open Access Journals (Sweden)

    T. Deshler

    2017-06-01

    Full Text Available Ozone plays a significant role in the chemical and radiative state of the atmosphere. For this reason there are many instruments used to measure ozone from the ground, from space, and from balloons. Balloon-borne electrochemical cell ozonesondes provide some of the best measurements of the ozone profile up to the mid-stratosphere, providing high vertical resolution, high precision, and a wide geographic distribution. From the mid-1990s to the late 2000s the consistency of long-term records from balloon-borne ozonesondes has been compromised by differences in manufacturers, Science Pump (SP and ENSCI (EN, and differences in recommended sensor solution concentrations, 1.0 % potassium iodide (KI and the one-half dilution: 0.5 %. To investigate these differences, a number of organizations have independently undertaken comparisons of the various ozonesonde types and solution concentrations, resulting in 197 ozonesonde comparison profiles. The goal of this study is to derive transfer functions to allow measurements outside of standard recommendations, for sensor composition and ozonesonde type, to be converted to a standard measurement and thus homogenize the data to the expected accuracy of 5 % (10 % in the stratosphere (troposphere. Subsets of these data have been analyzed previously and intermediate transfer functions derived. Here all the comparison data are analyzed to compare (1 differences in sensor solution composition for a single ozonesonde type, (2 differences in ozonesonde type for a single sensor solution composition, and (3 the World Meteorological Organization's (WMO and manufacturers' recommendations of 1.0 % KI solution for Science Pump and 0.5 % KI for ENSCI. From the recommendations it is clear that ENSCI ozonesondes and 1.0 % KI solution result in higher amounts of ozone sensed. The results indicate that differences in solution composition and in ozonesonde type display little pressure dependence at pressures

  13. Dissolved oxygen concentration in the medium during cell culture: Defects and improvements.

    Science.gov (United States)

    Zhang, Kuan; Zhao, Tong; Huang, Xin; He, Yunlin; Zhou, Yanzhao; Wu, Liying; Wu, Kuiwu; Fan, Ming; Zhu, Lingling

    2016-03-01

    In vitro cell culture has provided a useful model to study the effects of oxygen on cellular behavior. However, it remains unknown whether the in vitro operations themselves affect the medium oxygen levels and the living states of cells. In addition, a prevailing controversy is whether reactive oxygen species (ROS) production is induced by continuous hypoxia or reoxygenation. In this study, we have measured the effects of different types of cell culture containers and the oxygen environment where medium replacement takes place on the actual oxygen tension in the medium. We found that the deviations of oxygen concentrations in the medium are much greater in 25-cm(2) flasks than in 24-well plates and 35-mm dishes. The dissolved oxygen concentrations in the medium were increased after medium replacement in normoxia, but remained unchanged in glove boxes in which the oxygen tension remained at a low level (11.4, 5.7, and 0.5% O2 ). We also found that medium replacement in normoxia increased the number of ROS-positive cells and reduced the cell viability; meanwhile, medium replacement in a glove box did not produce the above effects. Therefore, we conclude that the use of 25-cm(2) flasks should be avoided and demonstrate that continuous hypoxia does not produce ROS, whereas the reoxygenation that occurs during the harvesting of cells leads to ROS and induces cell death. © 2015 International Federation for Cell Biology.

  14. Glial Cells: The Other Cells of the Nervous System

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 7; Issue 1. Glial Cells: The Other Cells of the Nervous System - An Introduction to Glial Cells. Medha S Rajadhyaksha Yasmin Khan. Series Article Volume 7 Issue 1 January 2002 pp 4-10 ...

  15. Thermal Management of Concentrated Multi-Junction Solar Cells with Graphene-Enhanced Thermal Interface Materials

    Directory of Open Access Journals (Sweden)

    Mohammed Saadah

    2017-06-01

    Full Text Available We report results of experimental investigation of temperature rise in concentrated multi-junction photovoltaic solar cells with graphene-enhanced thermal interface materials. Graphene and few-layer graphene fillers, produced by a scalable environmentally-friendly liquid-phase exfoliation technique, were incorporated into conventional thermal interface materials. Graphene-enhanced thermal interface materials have been applied between a solar cell and heat sink to improve heat dissipation. The performance of the multi-junction solar cells has been tested using an industry-standard solar simulator under a light concentration of up to 2000 suns. It was found that the application of graphene-enhanced thermal interface materials allows one to reduce the solar cell temperature and increase the open-circuit voltage. We demonstrated that the use of graphene helps in recovering a significant amount of the power loss due to solar cell overheating. The obtained results are important for the development of new technologies for thermal management of concentrated photovoltaic solar cells.

  16. Clusters of reaction rates and concentrations in protein networks such as the phosphotransferase system.

    Science.gov (United States)

    Härdin, Hanna M; Zagaris, Antonios; Willms, Allan R; Westerhoff, Hans V

    2014-01-01

    To understand the functioning of living cells, it is often helpful or even necessary to exploit inherent timescale disparities and focus on long-term dynamic behaviour. In the present study, we explore this type of behaviour for the biochemical network of the phosphotransferase system. We show that, during the slow phase that follows a fast initial transient, the network reaction rates are partitioned into clusters corresponding to connected parts of the reaction network. Rates within any of these clusters assume essentially the same value: differences within each cluster are vastly smaller than that from one cluster to another. This rate clustering induces an analogous clustering of the reactive compounds: only the molecular concentrations on the interface between these clusters are produced and consumed at substantially different rates and hence change considerably during the slow phase. The remaining concentrations essentially assume their steady-state values already by the end of the transient phase. Further, we find that this clustering phenomenon occurs for a large number of parameter values and also for models with different topologies; to each of these models, there corresponds a particular network partitioning. Our results show that, in spite of its complexity, the phosphotransferase system tends to behave in a rather simple (yet versatile) way. The persistence of clustering for the perturbed models we examined suggests that it is likely to be encountered in various environmental conditions, as well as in other signal transduction pathways with network structures similar to that of the phosphotransferase system. © 2013 FEBS.

  17. Relationship between haemoglobin concentration and packed cell volume in cattle blood samples

    Directory of Open Access Journals (Sweden)

    Paa-Kobina Turkson

    2015-02-01

    Full Text Available A convention that has been adopted in medicine is to estimate haemoglobin (HB concentration as a third of packed cell volume (PCV or vice versa. The present research set out to determine whether a proportional relationship exists between PCV and Hb concentration in cattle blood samples, and to assess the validity of the convention of estimating Hb concentration as a third of PCV. A total of 440 cattle in Ghana from four breeds (Ndama, 110; West African Short Horn, 110; Zebu, 110 and Sanga, 110 were bled for haematological analysis, specifically packed cell volume, using the microhaematocrit technique and haemoglobin concentration using the cyanmethaemoglobin method. Means, standard deviations, standard errors of mean and 95% confidence intervals were calculated. Trendline analyses generated linear regression equations from scatterplots. For all the cattle, a significant and consistent relationship (r = 0.74 was found between Hb concentration and PCV (%. This was expressed as Hb concentration (g/dL = 0.28 PCV + 3.11. When the Hb concentration was estimated by calculating it as a third of PCV, the relationship was expressed in linear regression as Hb concentration (g/dL = 0.83 calculated Hb + 3.11. The difference in the means of determined (12.2 g/dL and calculated (10.9 g/dL Hb concentrations for all cattle was significant (p < 0.001, whereas the difference in the means of determined Hb and corrected calculated Hb was not significant. In conclusion, a simplified relationship of Hb (g/dL = (0.3 PCV + 3 may provide a better estimate of Hb concentration from the PCV of cattle.

  18. Building integration of concentrating solar systems for heating applications

    International Nuclear Information System (INIS)

    Tsoutsou, Sapfo; Infante Ferreira, Carlos; Krieg, Jan; Ezzahiri, Mohamed

    2014-01-01

    A new solar collection system integrated on the façade of a building is investigated for Dutch climate conditions. The solar collection system includes a solar façade, a receiver tube and 10 Fresnel lenses. The Fresnel lenses Fresnel lenses considered were linear, non-imaging, line – focused with a system tracking the position of the sun that ensures vertical incidence of the direct solar radiation on the lenses. For the heating system a double-effect absorption heat pump, which requires high temperature of the heating fluid, was used, working with water and lithium-bromide as refrigerant and solution respectively. The Fresnel lens system is connected with the absorption heat pump through a thermal energy storage tank which accumulates the heat from the Fresnel lens system to provide it to the high pressure generator of the absorption heat pump. - Highlights: • The integration of Fresnel lenses in solar thermal building façades is investigated. • Using building integrated Fresnel lenses, 43% heating energy can be saved. • Energy savings in Mediterranean countries are significantly larger. • The absorption heat pump could make great contribution to energy savings for Dutch climate conditions

  19. Fundamentals of fuel cell system integration

    Science.gov (United States)

    Krumpelt, Michael; Kumar, Romesh; Myles, Kevin M.

    1994-04-01

    Fuel cells are theoretically very efficient energy conversion devices that have the potential of becoming a commercial product for numerous uses in the civilian economy. We have analyzed several fuel cell system designs with regard to thermal and chemical integration of the fuel cell stack into the rest of the system. Thermal integration permits the use of the stack waste heat for the endothermic steps of fuel reforming. Chemical integration provides the steam needed for fuel reforming from the water produced by the electrochemical cell reaction. High-temperature fuel cells, such as the molten carbonate and the solid oxide fuel cells, permit this system integration in a relatively simple manner. Lower temperature fuel cells, such as the polymer electrolyte and phosphoric acid systems, require added system complexity to achieve such integration. The system economics are affected by capital and fuel costs and technical parameters, such as electrochemical fuel utilization, current density, and system complexity. At today's low fuel prices and the high fuel cell costs (in part, because of the low rates of production of the early prototypes), fuel cell systems are not cost competitive with conventional power generation. With the manufacture and sale of larger numbers of fuel cell systems, the total costs will decrease from the current several thousand dollars per kW, to perhaps less than $100 per kW as production volumes approa ch a million units per year.

  20. A systematic method of interconnection optimization for dense-array concentrator photovoltaic system.

    Science.gov (United States)

    Siaw, Fei-Lu; Chong, Kok-Keong

    2013-01-01

    This paper presents a new systematic approach to analyze all possible array configurations in order to determine the most optimal dense-array configuration for concentrator photovoltaic (CPV) systems. The proposed method is fast, simple, reasonably accurate, and very useful as a preliminary study before constructing a dense-array CPV panel. Using measured flux distribution data, each CPV cells' voltage and current values at three critical points which are at short-circuit, open-circuit, and maximum power point are determined. From there, an algorithm groups the cells into basic modules. The next step is I-V curve prediction, to find the maximum output power of each array configuration. As a case study, twenty different I-V predictions are made for a prototype of nonimaging planar concentrator, and the array configuration that yields the highest output power is determined. The result is then verified by assembling and testing of an actual dense-array on the prototype. It was found that the I-V curve closely resembles simulated I-V prediction, and measured maximum output power varies by only 1.34%.

  1. Design and testing of a uniformly solar energy TIR-R concentration lenses for HCPV systems.

    Science.gov (United States)

    Shen, S C; Chang, S J; Yeh, C Y; Teng, P C

    2013-11-04

    In this paper, total internal reflection-refraction (TIR-R) concentration (U-TIR-R-C) lens module were designed for uniformity using the energy configuration method to eliminate hot spots on the surface of solar cell and increase conversion efficiency. The design of most current solar concentrators emphasizes the high-power concentration of solar energy, however neglects the conversion inefficiency resulting from hot spots generated by uneven distributions of solar energy concentrated on solar cells. The energy configuration method proposed in this study employs the concept of ray tracing to uniformly distribute solar energy to solar cells through a U-TIR-R-C lens module. The U-TIR-R-C lens module adopted in this study possessed a 76-mm diameter, a 41-mm thickness, concentration ratio of 1134 Suns, 82.6% optical efficiency, and 94.7% uniformity. The experiments demonstrated that the U-TIR-R-C lens module reduced the core temperature of the solar cell from 108 °C to 69 °C and the overall temperature difference from 45 °C to 10 °C, and effectively relative increased the conversion efficiency by approximately 3.8%. Therefore, the U-TIR-R-C lens module designed can effectively concentrate a large area of sunlight onto a small solar cell, and the concentrated solar energy can be evenly distributed in the solar cell to achieve uniform irradiance and effectively eliminate hot spots.

  2. System for concentrating and analyzing particles suspended in a fluid

    Science.gov (United States)

    Fiechtner, Gregory J [Bethesda, MD; Cummings, Eric B [Livermore, CA; Singh, Anup K [Danville, CA

    2011-04-26

    Disclosed is a device for separating and concentrating particles suspended in a fluid stream by using dielectrophoresis (DEP) to trap and/or deflect those particles as they migrate through a fluid channel. The method uses fluid channels designed to constrain a liquid flowing through it to uniform electrokinetic flow velocities. This behavior is achieved by connecting deep and shallow sections of channels, with the channel depth varying abruptly along an interface. By careful design of abrupt changes in specific permeability at the interface, an abrupt and spatially uniform change in electrokinetic force can be selected. Because these abrupt interfaces also cause a sharp gradient in applied electric fields, a DEP force also can be established along the interface. Depending on the complex conductivity of the suspended particles and the immersion liquid, the DEP force can controllably complement or oppose the local electrokinetic force transporting the fluid through the channel allowing for manipulation of particles suspended in the transporting liquid.

  3. Cell boundary fault detection system

    Science.gov (United States)

    Archer, Charles Jens [Rochester, MN; Pinnow, Kurt Walter [Rochester, MN; Ratterman, Joseph D [Rochester, MN; Smith, Brian Edward [Rochester, MN

    2009-05-05

    A method determines a nodal fault along the boundary, or face, of a computing cell. Nodes on adjacent cell boundaries communicate with each other, and the communications are analyzed to determine if a node or connection is faulty.

  4. A 75-kW methanol reforming fuel cell system

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Xiqiang; Wang, Shudong; Li, Xiangyi; Hou, Ming; Yuan, Zhongshan; Li, Deyi; Pan, Liwei; Zhang, Cheng; Liu, Jingkai; Ming, Pingwen; Yi, Baolian [Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China)

    2006-11-22

    A 75-kW methanol reforming fuel cell system, which consists of a fuel cell system and a methanol auto-thermal reforming fuel processor has been developed at Dalian Institute of Chemical Physics, Chinese Academy of Sciences (CAS). The core of the fuel cell system is a group of CO tolerant PEMFC stacks with a double layer composite structured anode. The fuel cell stacks show good CO tolerance even though 140ppm CO was present in the reformate stream during transients. The auto-thermal reforming (ATR) fuel cell processor could adiabatically produce a suitable reformate without external energy consumption. The output of hydrogen-rich reformate was approximately 120Nm{sup 3}h{sup -1} with a H{sub 2} content near 53% and the CO concentrations generally were under 30ppm. The fuel cell system was integrated with the methanol reforming fuel processor and the peak power output of the fuel cell system exceeded 75kW in testing. The hydrogen utilization approached 70% in the fuel cell system. (author)

  5. Glial Cells: The Other Cells of the Nervous System ...

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 7; Issue 6. Glial Cells: The Other Cells of the Nervous System - Oligodendrocytes – Ensheathers of the CNS. Yasmin Khan Medha S Rajadhyaksha. Series Article Volume 7 Issue 6 June 2002 pp 6-13 ... Keywords. Glia; myelin; central nervous system.

  6. Immobilized yeast cell systems for continuous fermentation applications.

    Science.gov (United States)

    Verbelen, Pieter J; De Schutter, David P; Delvaux, Filip; Verstrepen, Kevin J; Delvaux, Freddy R

    2006-10-01

    In several yeast-related industries, continuous fermentation systems offer important economical advantages in comparison with traditional systems. Fermentation rates are significantly improved, especially when continuous fermentation is combined with cell immobilization techniques to increase the yeast concentration in the fermentor. Hence the technique holds a great promise for the efficient production of fermented beverages, such as beer, wine and cider as well as bio-ethanol. However, there are some important pitfalls, and few industrial-scale continuous systems have been implemented. Here, we first review the various cell immobilization techniques and reactor setups. Then, the impact of immobilization on cell physiology and fermentation performance is discussed. In a last part, we focus on the practical use of continuous fermentation and cell immobilization systems for beer production.

  7. Community structure dynamics during startup in microbial fuel cells - The effect of phosphate concentrations.

    Science.gov (United States)

    Yanuka-Golub, Keren; Reshef, Leah; Rishpon, Judith; Gophna, Uri

    2016-07-01

    For microbial fuel cells (MFCs) to become a cost-effective wastewater treatment technology, they must produce a stable electro-active microbial community quickly and operate under realistic wastewater nutrient conditions. The composition of the anodic-biofilm and planktonic-cells communities was followed temporally for MFCs operated under typical laboratory phosphate concentrations (134mgL(-1)P) versus wastewater phosphate concentrations (16mgL(-1)P). A stable peak voltage was attained two-fold faster in MFCs operating under lower phosphate concentration. All anodic-biofilms were composed of well-known exoelectrogenic bacterial families; however, MFCs showing faster startup and a stable voltage had a Desulfuromonadaceae-dominated-biofilm, while biofilms co-dominated by Desulfuromonadaceae and Geobacteraceae characterized slower or less stable MFCs. Interestingly,planktonic-cell concentrations of these bacteria followed a similar trend as the anodic-biofilm and could therefore serve as a biomarker for its formation. These results demonstrate that wastewater-phosphate concentrations do not compromise MFCs efficiency, and considerably speed up startup times. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. BIOCOMPATIBILITY OF LEUKOCYTE REMOVAL FILTERS DURING BEDSIDE LEUKOCYTE FILTRATION OF RED-CELL CONCENTRATES

    NARCIS (Netherlands)

    GU, YJ; OBSTER, R; DEHAAN, J; HUET, RCGG; VANOEVEREN, W

    1992-01-01

    The biocompatibility of leukocyte removal filters was evaluated in four different types of leukocyte filters made from different materials during bedside leukocyte filtration of red cell concentrates (RCC). Two units of banked RCC were filtrated through each leukocyte filter inserted into the

  9. Mast cell concentration and skin wound contraction in rats treated with Ximenia americana L.

    Science.gov (United States)

    Castro Souza Junior Neto, José de; Estevão, Lígia Reis de Moura; Baratella-Evêncio, Liriane; Vieira, Marcela Gabriela Feitosa; Simões, Ricardo Santos; Florencio-Silva, Rinaldo; Evêncio-Luz, Luís; Evêncio-Neto, Joaquim

    2017-02-01

    To evaluate wound contraction and the concentration of mast cells in skin wounds treated with wild plum (Ximenia americana) essential oil-based ointment in rats. Sixty rats were submitted to two cutaneous wounds in the thoracic region, on the right and left antimeres. Thereon, they were divided into three groups: GX (wounds treated once a day with hydro alcoholic branch extract of Ximenia americana), GP (wounds that received vehicle), and GC (wounds without product application). Wounds were measured immediately after the injury as well as 4, 7, 14 and 21 days post-topical application of the extract. At these days, five rats from each group were euthanatized. Thereafter, samples were fixed in 10% formaldehyde and processed for paraffin embedding. Sections were stained with H.E, Masson's Trichrome and toluidine blue for morphological, morphometrical and histopathological analysis, under light microscopy. The degree of epithelial contraction was measured and mast cell concentrations were also evaluated with an image analyzer (Image Pro-plus®software) . The extract treated group showed lower mast cell concentrations in the 4th day of lesion, as compared to GP (GX GP = GC; pamericana induces a decrease in mast cell concentration, at the beginning of the healing process, and promotes early skin wound contraction in rats.

  10. A new cellulose acetate filter to remove leukocytes from buffy-coat-poor red cell concentrates

    NARCIS (Netherlands)

    Pietersz, R. N.; Dekker, W. J.; Reesink, H. W.

    1989-01-01

    Transfusion of leukocyte-free red cell concentrates (RCC) prevents or delays HLA immunization in multitransfused patients. We investigated a new cellulose acetate filter which was recently introduced to remove leukocytes from buffy-coat-poor RCC. It was found that the filtration time was only 10 min

  11. Bone marrow concentrated cell transplantation: rationale for its use in the treatment of human osteochondral lesions.

    Science.gov (United States)

    Cavallo, C; Desando, G; Cattini, L; Cavallo, M; Buda, R; Giannini, S; Facchini, A; Grigolo, B

    2013-01-01

    Bone marrow is one of the best characterized stem cell microenvironments that contains Mesenchymal Stem Cells (MSCs), a rare population of non-hematopoietic stromal cells. MSCs have been indicated as a new option for regenerative medicine because of their ability to differentiate into various lineages such as bone, cartilage and adipose tissue. However, isolation procedures are crucial for the functional activity of the transplanted cells. The use of concentrated bone marrow cells (BMCs) enables a cell population surrounded by its microenvironment (niche) to be implanted while avoiding all the complications related to the in vitro culture. The cells of the niche are able to regulate stem cell behavior through direct physical contact and secreting paracrine factors. The aim of this study was to characterize BMCs in vitro to evaluate their ability to differentiate toward mature cells and try to understand whether there are differences in the chondrogenic and osteogenic potential of cells from patients of different ages. Mononuclear Cells (MNCs) isolated by Ficoll were used as control. Both cell populations were grown in monolayers and differentiated with specific factors and analyzed by histological and molecular biology assays to evaluate the expression of some specific extracellular matrix molecules. The present investigations revealed the ability of BMCs to act as isolated cells. They are able to form colonies and differentiate toward chondrogenic and osteogenic lineages, the latter pathway appearing to be influenced by donor age. The results obtained by this study support the use of BMCs in clinical practice for the repair of osteochondral damage, which might be particularly useful for the one-step procedure allowing cells to be directly implanted in operating room.

  12. Well-Controlled Cell-Trapping Systems for Investigating Heterogeneous Cell-Cell Interactions.

    Science.gov (United States)

    Kamiya, Koki; Abe, Yuta; Inoue, Kosuke; Osaki, Toshihisa; Kawano, Ryuji; Miki, Norihisa; Takeuchi, Shoji

    2018-03-01

    Microfluidic systems have been developed for patterning single cells to study cell-cell interactions. However, patterning multiple types of cells to understand heterogeneous cell-cell interactions remains difficult. Here, it is aimed to develop a cell-trapping device to assemble multiple types of cells in the well-controlled order and morphology. This device mainly comprises a parylene sheet for assembling cells and a microcomb for controlling the cell-trapping area. The cell-trapping area is controlled by moving the parylene sheet on an SU-8 microcomb using tweezers. Gentle downward flow is used as a driving force for the cell-trapping. The assembly of cells on a parylene sheet with round and line-shaped apertures is demonstrated. The cell-cell contacts of the trapped cells are then investigated by direct cell-cell transfer of calcein via connexin nanopores. Finally, using the device with a system for controlling the cell-trapping area, three different types of cells in the well-controlled order are assembled. The correct cell order rate obtained using the device is 27.9%, which is higher than that obtained without the sliding parylene system (0.74%). Furthermore, the occurrence of cell-cell contact between the three cell types assembled is verified. This cell-patterning device will be a useful tool for investigating heterogeneous cell-cell interactions. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Design of a NIR concentrator system integrated in a greenhouse

    NARCIS (Netherlands)

    Piet Sonneveld; Gert-Jan Swinkels; H.J.J. Janssen; B.A.J. van Tuijl

    2012-01-01

    In this paper the design and development of a new type of greenhouse with an integrated filter for reflecting near infrared radiation (NIR) and a solar energy delivery system is described. Especially the optical parts as the spectral selective film, the properties of the circular reflector and the

  14. The concentration gradient flow battery as electricity storage system

    NARCIS (Netherlands)

    Egmond, Van W.J.; Saakes, M.; Porada, S.; Meuwissen, T.; Buisman, C.J.N.; Hamelers, H.V.M.

    2016-01-01

    Unlike traditional fossil fuel plants, the wind and the sun provide power only when the renewable resource is available. To accommodate large scale use of renewable energy sources for efficient power production and utilization, energy storage systems are necessary. Here, we introduce a scalable

  15. The different effects on cranial and trunk neural crest cell behaviour following exposure to a low concentration of alcohol in vitro.

    Science.gov (United States)

    Czarnobaj, Joanna; Bagnall, Keith M; Bamforth, J Steven; Milos, Nadine C

    2014-05-01

    Embryonic neural crest cells give rise to large regions of the face and peripheral nervous system. Exposure of these cells to high alcohol concentrations leads to cell death in the craniofacial region resulting in facial defects. However, the effects of low concentrations of alcohol on neural crest cells are not clear. In this study, cranial neural crest cells from Xenopus laevis were cultured in an ethanol concentration approximately equivalent to one drink. Techniques were developed to study various aspects of neural crest cell behaviour and a number of cellular parameters were quantified. In the presence of alcohol, a significant number of cranial neural crest cells emigrated from the explant on fibronectin but the liberation of individual cells was delayed. The cells also remained close to the explant and their morphology changed. Cranial neural crest cells did not grow on Type 1 collagen. For the purposes of comparison, the behaviour of trunk neural crest cells was also studied. The presence of alcohol correlated with increased retention of single cells on fibronectin but left other parameters unchanged. The behaviour of trunk neural crest cells growing on Type 1 collagen in the presence of alcohol did not differ from controls. Low concentrations of alcohol therefore significantly affected both cranial and trunk neural crest cells, with a wider variety of effects on cells from the cranial as opposed to the trunk region. The results suggest that low concentrations of alcohol may be more detrimental to early events in organ formation than currently suspected. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Anticancer effects of clinically acceptable colchicine concentrations on human gastric cancer cell lines.

    Science.gov (United States)

    Lin, Zu-Yau; Kuo, Chao-Hung; Wu, Deng-Chyang; Chuang, Wan-Long

    2016-02-01

    Colchicine is a very cheap microtubule destabilizer. Because microtubules are an ideal target for anticancer drugs, the purpose of this study was to investigate whether clinically acceptable colchicine concentrations have anticancer effects on gastric cancer cells, and its possible anticancer mechanisms. Two human gastric cancer cell lines (i.e., AGS and NCI-N87) were investigated by proliferative assay, microarray, quantitative reverse transcriptase-polymerase chain reaction, and a nude mice study using clinically acceptable colchicine concentrations (2 ng/mL and 6 ng/mL for in vitro tests and 0.07 mg colchicine/kg/d for in vivo tests). Our results showed that colchicine had the same inhibitory effects on the proliferation of both cell lines. The antiproliferative effects of colchicine on both cell lines were achieved only at the concentration of 6 ng/mL (p colchicine, compared with 2 ng/mL colchicine. Among these genes, only the upregulated DUSP1 gene may contribute to the antiproliferative effects of colchicine on gastric cancer cells. The nude mice (BALB/c-nu) experiment showed that colchicine-treated mice after 14 days of treatment had lower increased tumor volume ratios (p = 0.0199) and tumor growth rates (p = 0.024) than the control mice. In conclusion, colchicine has potential for the palliative treatment of gastric cancer. However, the anticancer effects are achieved only at high clinically acceptable colchicine concentrations. Monitoring the colchicine plasma concentration is mandatory if this drug is applied for the palliative treatment of gastric cancer. Copyright © 2016. Published by Elsevier Taiwan.

  17. Spectral and Concentration Sensitivity of Multijunction Solar Cells at High Temperature: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Friedman, Daniel J.; Steiner, Myles A.; Perl, Emmett E.; Simon, John

    2017-06-14

    We model the performance of two-junction solar cells at very high temperatures of ~400 degrees C and beyond for applications such as hybrid PV/solar-thermal power production, and identify areas in which the design and performance characteristics behave significantly differently than at more conventional near-room-temperature operating conditions. We show that high-temperature operation reduces the sensitivity of the cell efficiency to spectral content, but increases the sensitivity to concentration, both of which have implications for energy yield in terrestrial PV applications. For other high-temperature applications such as near-sun space missions, our findings indicate that concentration may be a useful tool to enhance cell efficiency.

  18. Effect of initial salt concentrations on cell performance and distribution of internal resistance in microbial desalination cells.

    Science.gov (United States)

    Yang, Euntae; Choi, Mi-Jin; Kim, Kyoung-Yeol; Chae, Kyu-Jung; Kim, In S

    2015-01-01

    Microbial desalination cells (MDCs) are modified microbial fuel cells (MFCs) that concurrently produce electricity and desalinate seawater, but adding a desalination compartment and an ion-exchange membrane may increase the internal resistance (Ri), which can limit the cell performance. However, the effects of a desalination chamber and initial NaCl concentrations on the internal resistances and the cell performances (i.e. Coulombic efficiency (CE), current and power density) of MDCs have yet to be thoroughly explored; thus, the cell performance and Ri distributions of MDCs having different initial concentrations and an MFC having no desalination chamber were compared. In the MDCs, the current and power density generation increased from 2.82 mA and 158.2 mW/m2 to 3.17 mA and 204.5 mW/m2 when the initial NaCl concentrations were increased from 5 to 30 g/L, as a consequence of the internal resistances decreasing from 2432.0 to 2328.4 Ω. And even though the MFC has a lower Ri than the MDCs, lower cell performances (current: 2.59 mA; power density: 141.6 mW/m2 and CE: 62.1%) were observed; there was no effect of improved junction potential in the MFC. Thus, in the MDCs, the higher internal resistances due to the addition of a desalination compartment can be offset by reducing the electrolyte resistance and improving the junction potential at higher NaCl concentrations.

  19. Study on direct-contact phase-change liquid immersion cooling dense-array solar cells under high concentration ratios

    International Nuclear Information System (INIS)

    Kang, Xue; Wang, Yiping; Huang, Qunwu; Cui, Yong; Shi, Xusheng; Sun, Yong

    2016-01-01

    Highlights: • Direct-contact phase-change liquid immersion cooling for solar cells was proposed. • A self-regulating system investigated the feasibility in temperature control. • Temperature was well controlled between 87.3 °C and 88.5 °C. • Surface heat transfer coefficient was up to 23.49 kW/(m 2 ·K) under 398.4×. • A model illustrated the interface function was the main reason to affect light. - Abstract: A new cooling method by directly immersing the solar cells into phase-change liquid was put forward to cool dense-array solar cells in high concentrating photovoltaic system. A self-running system was built to study the feasibility of temperature control and the effect of bubbles generated by ethanol phase change under concentration ratio ranged between 219.8× and 398.4×. The results show that the cooling system is self-regulating without consuming extra energy and ethanol flow rate reaches up to 180.6 kg/(s·m 2 ) under 398.4×. The temperature of solar cells distributes in the range between 87.3 °C and 88.5 °C, the surface heat transfer coefficient of electric heating plate is up to 23.49 kW/(m 2 ·K) under 398.4×. The bubble effect on electrical performance of triple-junction solar cells is reported and the results show that I sc and P max decline 10.2% and 7.3%, respectively. A model based on bubble images illustrates that light loss at the interface between ethanol and bubble is the main reason to cut down the electrical performance.

  20. Increased serum concentration of immune cell derived microparticles in polymyositis/dermatomyositis.

    Science.gov (United States)

    Baka, Zsuzsanna; Senolt, Ladislav; Vencovsky, Jiri; Mann, Herman; Simon, Piroska Sebestyén; Kittel, Agnes; Buzás, Edit; Nagy, György

    2010-02-16

    Microparticles are recently recognized players of intercellular communication. They are involved in signal transduction, cell activation and apoptosis. Their importance is also suggested in autoimmune diseases such as rheumatoid arthritis and systemic sclerosis. We investigated the role of microparticles in polymyositis/dermatomyositis, a group of rare autoimmune diseases, characterized by specific skin lesions and muscle weakness. The plasma concentration of monocyte and lymphocyte derived microparticles of 20 patients with polymyositis/dermatomyositis and 20 healthy controls were determined by flow cytometry. The structure of microparticles was visualized by electron microscopy. Significantly elevated numbers of monocyte (CD14 positive), T-lymphocyte (CD3 positive) and B-lymphocyte (CD19 positive) derived microparticles were found in the plasma samples of polymyositis/dermatomyositis patients, compared to healthy controls (p=0.001, 0.01 and 0.006, respectively). Furthermore, the plasma levels of monocyte and B-lymphocyte derived microparticles correlated with the manual muscle strength test (r=0.497, p=0.027; r=0.508, p=0.023; respectively). Patients with anti-Jo-1 antibody and lung involvement had significantly higher numbers of T- and B-lymphocyte and monocyte derived MPs (p=0.006, 0.012 and 0.007, respectively, for anti-Jo-1; p=0.013, 0.016 and 0.025, respectively, for lung involvement). After ultracentrifugation, CK activity could be detected only in traces in the resuspended pellet containing microparticles of healthy and diseased individuals. The electron microscopy revealed slightly different microparticles in the samples of patients with polymyositis/dermatomyositis. These results suggest that immune cell derived microparticles may contribute to the inflammatory process in polymyositis/dermatomyositis, however, CK-positive, possibly muscle derived microparticles do not seem to be present in the blood of patients with polymyositis

  1. Effects of low concentrations of Regorafenib and Sorafenib on human HCC cell AFP, migration, invasion and growth in vitro

    Science.gov (United States)

    Carr, Brian Irving; D’Alessandro, Rosalba; Refolo, Maria Grazia; Iacovazzi, Palma Aurelia; Lippolis, Catia; Messa, Caterina; Cavallini, Aldo; Correale, Mario; Di Carlo, Antonio

    2012-01-01

    Sorafenib was shown in clinical trial to enhance survival in hepatocellular carcinoma (HCC) patients, but with minimal tumor shrinkage. To correlate several indices of HCC growth at various drug concentrations, HCC cells were grown in various low concentrations of two multi-kinase inhibitors, Regorafenib (Stivarga) and Sorafenib (Nexavar) and their effects were examined on alpha-fetoprotein (AFP), cell growth, migration and invasion. In two AFP positive human HCC cell lines, AFP was inhibited at 0.1–1µM drug concentrations. Cell migration and invasion were also inhibited at similar low drug concentrations. However, 10-fold higher drug concentrations were required to inhibit cell growth in both AFP positive and negative cells. To investigate this concentration discrepancy of effects, cells were then grown for prolonged times and sub-cultured in low drug concentrations and then their growth was re-tested. The growth in these drug-exposed cells was found to be slower than cells without prior drug exposure and they were also more sensitive to subsequent drug challenge. Evidence was also found for changes in cell signaling pathways in these slow-growth cells. Low multi-kinase inhibitor concentrations thus modulate several aspects of HCC cell biology. PMID:23169148

  2. System for adding sulfur to a fuel cell stack system for improved fuel cell stability

    Science.gov (United States)

    Mukerjee, Subhasish [Pittsford, NY; Haltiner, Jr., Karl J; Weissman, Jeffrey G [West Henrietta, NY

    2012-03-06

    A system for adding sulfur to a fuel cell stack, having a reformer adapted to reform a hydrocarbon fuel stream containing sulfur contaminants, thereby providing a reformate stream having sulfur; a sulfur trap fluidly coupled downstream of the reformer for removing sulfur from the reformate stream, thereby providing a desulfurized reformate stream; and a metering device in fluid communication with the reformate stream upstream of the sulfur trap and with the desulfurized reformate stream downstream of the sulfur trap. The metering device is adapted to bypass a portion of the reformate stream to mix with the desulfurized reformate stream, thereby producing a conditioned reformate stream having a predetermined sulfur concentration that gives an acceptable balance of minimal drop in initial power with the desired maximum stability of operation over prolonged periods for the fuel cell stack.

  3. Concentrated photovoltaics system costs and learning curve analysis

    Science.gov (United States)

    Haysom, Joan E.; Jafarieh, Omid; Anis, Hanan; Hinzer, Karin

    2013-09-01

    An extensive set of costs in /W for the installed costs of CPV systems has been amassed from a range of public sources, including both individual company prices and market reports. Cost reductions over time are very evident, with current prices for 2012 in the range of 3.0 ± 0.7 /W and a predicted cost of 1.5 /W for 2020. Cost data is combined with deployment volumes in a learning curve analysis, providing a fitted learning rate of either 18.5% or 22.3% depending on the methodology. This learning rate is compared to that of PV modules and PV installed systems, and the influence of soft costs is discussed. Finally, if an annual growth rate of 39% is assumed for deployed volumes, then, using the learning rate of 20%, this would predict the achievement of a cost point of 1.5 /W by 2016.

  4. Systems Biology and Stem Cell Pluripotency

    DEFF Research Database (Denmark)

    Mashayekhi, Kaveh; Hall, Vanessa Jane; Freude, Kristine

    2016-01-01

    Recent breakthroughs in stem cell biology have accelerated research in the area of regenerative medicine. Over the past years, it has become possible to derive patient-specific stem cells which can be used to generate different cell populations for potential cell therapy. Systems biological...... improve systems biology and its uses in the field. In this chapter, we first give a general background on stem cell biology and regenerative medicine. Stem cell potency is introduced together with the hierarchy of stem cells ranging from pluripotent embryonic stem cells (ESCs) and induced pluripotent stem...... modeling of stem cell pluripotency and differentiation have largely been based on prior knowledge of signaling pathways, gene regulatory networks, and epigenetic factors. However, there is a great need to extend the complexity of the modeling and to integrate different types of data, which would further...

  5. Design and Control of High Temperature PEM Fuel Cell System

    DEFF Research Database (Denmark)

    Andreasen, Søren Juhl

    demands for this. A 1kW fuel cell stack with optimized  ow plates was heated in 5 minutes using the introduction of an electrical air pre-heater. Using pure hydrogen in compressed form is problematic due to the very small density of hydrogen, even at high pressures. Hydrogen is a very energy e-cient gas...... enables the use of designing cathode air cooled stacks greatly simplifying the fuel cell system and lowering the parasitic losses. Furthermore, the fuel impurity tolerance is signicantly improved because of the higher temperatures, and much higher concentrations of CO can be endured without performance...... or life time losses. In order to evaluate the performance of using HTPEM fuel cells for electricity production in electrical applications, a 400 W fuel cell system is initially designed using a cathode air cooled 30 cell HTPEM stack. The stack runs on pure hydrogen in a deadend anode configuration...

  6. CLINICAL VALUE OF BAFF AND APRIL CONCENTRATIONS IN SYSTEMIC LUPUS ERYTHEMATOSUS

    Directory of Open Access Journals (Sweden)

    T. A. Panafidina

    2016-01-01

    Full Text Available Systemic lupus erythematosus (SLE is characterized by the pathological activation and differentiation of B lymphocytes. The B-lymphocyte stimulator (BLyS, also known as B cell-activating factor of the tumor necrosis factor family (BAFF, and its homologue, a proliferation-inducing ligand (APRIL, belong to the ligands of the tumor necrosis factor (TNF family and play a key role in B-lymphocyte selection and survival.Objective: to determine serum BAFF and APRIL concentrations in patients with SLE and a relationship of the clinical and laboratory parameters of the disease to the level of these cytokines.Subjects and methods. The investigation enrolled 73 patients (62 women and 11 men; median age, 30.0 [28.0; 46.0] years with SLE (disease duration, 5.0 [1.5; 11.0] years and its high activity (the median SLEDAI-2K scores of 8 [2; 13].Involvement of the kidneys and joints were found in 40 and 36% of cases, respectively; there were hematologic disorders in 38%, antinuclear factor (ANF in 94.5%, and anti-double stranded DNA antibodies in 77%. The concurrent antiphospholipid syndrome was detected in 15% of the patients. 66% of the patients took glucocorticoids (GCs (the median dose was 10 [0; 15] mg/day, calculated with reference to prednisolone, 42% received cytotoxic drugs (cyclophosphamide, mycophenolate mofetil, azathioprine; 12% used biological agents (BAs; 31.5% received no therapy at enrolment in the investigation. Serum BAFF and APRIL concentrations were estimated using an enzyme immunoassay.Results and discussion. The concentrations of BAFF and APRIL did not differ essentially in the patients with SLE and in the controls: the median level of BAFF was 0.02 [0.01; 0.64] and 0.02 [0.01; 0.03] ng/ml; that of APRIL was 2.09 [0.01; 3.80] and 0.01 [0.01; 4.16] ng/ml, respectively. The elevated concentration of BAFF (>0.82 ng/ml was revealed in 5.5% of the patients with SLE and that of APRIL (>5.96 ng/ml in 4.1%. There was a positive correlation between

  7. [Effects of glucose concentration fluctuation on function of cultured bovine arterial endothelial cells].

    Science.gov (United States)

    Ye, Xi-yun; Tu, Qian; Tong, Zhi; Weng, Yu-jing; Wang, Yao-fa

    2010-03-01

    To explore the effects of glucose concentration fluctuation on function of cultured bovine arterial endothelial cells and underlying mechanism. The thoracic aorta of newborn calf was used for primary endothelial cells culture. Cells were divided into 3 groups and cultured for 48 h: control group (C, 5.5 mmol/L), constant high glucose group (HG, 30 mmol/L) and glucose fluctuation (GF, three circles of 2 h 30 mmol/L followed by 3 h 5.5 mmol/L, 30 mmol/L overnight, repeat the whole procedure on the following day) groups. The membranes fluidity of endothelial cells was detected by fluorescence polarization method. The contents of sorbierite, aldose reductase (AR), sorbitol dehydrogenase (SDH) and advanced glycation end products (AGEs) were measured. RAGE, eNOS and ET-1 mRNA expressions were detected by semi-quantitative RT-PCR. The membranes fluidity of endothelial cells in HG or GF group were significantly decreased compared with the control group (all P RAGE, eNOS and ET-1 were significantly upregulated compared with the control group (all P bovine arterial endothelial cells dysfunction than high glucose via activating polyols metabolic pathways, upregulating the expression of AGEs, eNOS and ET-1. Therefore, glucose concentration fluctuation might play a crucial role on macrovascular complications of diabetes.

  8. Fuel quality issues in stationary fuel cell systems.

    Energy Technology Data Exchange (ETDEWEB)

    Papadias, D.; Ahmed, S.; Kumar, R. (Chemical Sciences and Engineering Division)

    2012-02-07

    Fuel cell systems are being deployed in stationary applications for the generation of electricity, heat, and hydrogen. These systems use a variety of fuel cell types, ranging from the low temperature polymer electrolyte fuel cell (PEFC) to the high temperature solid oxide fuel cell (SOFC). Depending on the application and location, these systems are being designed to operate on reformate or syngas produced from various fuels that include natural gas, biogas, coal gas, etc. All of these fuels contain species that can potentially damage the fuel cell anode or other unit operations and processes that precede the fuel cell stack. These detrimental effects include loss in performance or durability, and attenuating these effects requires additional components to reduce the impurity concentrations to tolerable levels, if not eliminate the impurity entirely. These impurity management components increase the complexity of the fuel cell system, and they add to the system's capital and operating costs (such as regeneration, replacement and disposal of spent material and maintenance). This project reviewed the public domain information available on the impurities encountered in stationary fuel cell systems, and the effects of the impurities on the fuel cells. A database has been set up that classifies the impurities, especially in renewable fuels, such as landfill gas and anaerobic digester gas. It documents the known deleterious effects on fuel cells, and the maximum allowable concentrations of select impurities suggested by manufacturers and researchers. The literature review helped to identify the impurity removal strategies that are available, and their effectiveness, capacity, and cost. A generic model of a stationary fuel-cell based power plant operating on digester and landfill gas has been developed; it includes a gas processing unit, followed by a fuel cell system. The model includes the key impurity removal steps to enable predictions of impurity breakthrough

  9. Effects of Subminimum Inhibitory Concentrations of Antibiotics on the Pasteurella multocida Proteome: A Systems Approach

    Directory of Open Access Journals (Sweden)

    Bindu Nanduri

    2008-01-01

    Full Text Available To identify key regulators of subminimum inhibitory concentration (sub-MIC antibiotic response in the Pasteurella multocida proteome, we applied systems approaches. Using 2D-LC-ESI-MS2, we achieved 53% proteome coverage. To study the differential protein expression in response to sub-MIC antibiotics in the context of protein interaction networks, we inferred P. multocida Pm70 protein interaction network from orthologous proteins. We then overlaid the differential protein expression data onto the P. multocida protein interaction network to study the bacterial response. We identified proteins that could enhance antimicrobial activity. Overall compensatory response to antibiotics was characterized by altered expression of proteins involved in purine metabolism, stress response, and cell envelope permeability.

  10. Effect of KOH concentration on LEO cycle life of IPV nickel-hydrogen flight battery cells

    Science.gov (United States)

    Smithrick, John J.; Hall, Stephen W.

    1990-01-01

    A breakthrough in the low-earth-orbit (LEO) cycle life of individual pressure vessel (IPV) nickel hydrogen battery cells is reported. The cycle life of boiler plate cells containing 26 percent potassium hydroxide (KOH) electrolyte was about 40,000 LEO cycles compared to 3500 cycles for cells containing 31 percent KOH. The effect of KOH concentration on cycle life was studied. The cycle regime was a stressful accelerated LEO, which consisted of a 27.5 min charge followed by a 17.5 min charge (2 x normal rate). The depth of discharge (DOD) was 80 percent. The cell temperature was maintained at 23 C. The next step is to validate these results using flight hardware and real time LEO test. NASA Lewis has a contract with the Naval Weapons Support Center (NWSC), Crane, Indiana to validate the boiler plate test results. Six 48 A-hr Hughes recirculation design IPV nickel-hydrogen flight battery cells are being evaluated. Three of the cells contain 26 percent KOH (test cells) and three contain 31 percent KOH (control cells). They are undergoing real time LEO cycle life testing. The cycle regime is a 90-min LEO orbit consisting of a 54-min charge followed by a 36-min discharge. The depth-of-discharge is 80 percent. The cell temperature is maintained at 10 C. The cells were cycled for over 8000 cycles in the continuing test. There were no failures for the cells containing 26 percent KOH. There were two failures, however, for the cells containing 31 percent KOH.

  11. Novel double-stage high-concentrated solar hybrid photovoltaic/thermal (PV/T) collector with nonimaging optics and GaAs solar cells reflector

    International Nuclear Information System (INIS)

    Abdelhamid, Mahmoud; Widyolar, Bennett K.; Jiang, Lun; Winston, Roland; Yablonovitch, Eli; Scranton, Gregg; Cygan, David; Abbasi, Hamid; Kozlov, Aleksandr

    2016-01-01

    Highlights: • A novel hybrid concentrating photovoltaic thermal (PV/T) collector is developed. • Thermal component achieves 60× concentration using nonimaging optics. • GaAs solar cells used as spectrally selective mirrors for low energy photons. • Thermal efficiencies of 37% at 365 °C and electrical efficiencies of 8% achieved. • Combined electric efficiency reaches 25% of DNI for system cost of $283.10/m 2. - Abstract: A novel double stage high-concentration hybrid solar photovoltaic thermal (PV/T) collector using nonimaging optics and world record thin film single-junction gallium arsenide (GaAs) solar cells has been developed. We present a detailed design and simulation of the system, experimental setup, prototype, system performance, and economic analysis. The system uses a parabolic trough (primary concentrator) to focus sunlight towards a secondary nonimaging compound parabolic concentrator (CPC) to simultaneously generate electricity from single junction GaAs solar cells, as well as high temperature dispatchable heat. This study is novel in that (a) the solar cells inside the vacuum tube act as spectrally selective mirrors for lower energy photons to maximize the system exergy, and (b) secondary concentrator allows the thermal component to reach a concentration ratio ∼60×, which is significantly higher than conventional PV/T concentration ratios. The maximum outlet temperature reached was 365 °C, and on average the thermal efficiency of the experiment was around 37%. The maximum electrical efficiency was around 8%. The total system electricity generation is around 25% of incoming DNI, by assuming the high temperature stream is used to power a steam turbine. The installed system cost per unit of parabolic trough aperture area is $283.10 per m 2 .

  12. The effect of increased centrifugation temperature on the quality of red-blood-cell concentrates of automated whole blood processing.

    Science.gov (United States)

    Weinigel, C; Rummler, S; Barz, D

    2013-10-01

    There are manual and automated methods to separate whole blood (WB) available. The Atreus whole blood processing system is an automated method, which combines centrifugation and expression of components into a single device. A major difference to conventional methods is that centrifugation temperature is not controlled at 22°C. The aim of this study was to examine the influence of increased centrifugation temperatures on the quality of red-blood-cell concentrates (RCC) after active cooling of WB prior to processing. A total of 28 WB were processed: 16 at centrifugation temperatures of up to 28°C (1st protocol) and 12 at 34°C (2nd protocol). RCC quality parameters were tested weekly for 42 days. Red-blood-cell concentrates (RCC) quality complied with the European and German guidelines. Haemolysis was not significantly different throughout storage. Significant statistical differences were detected between both protocols in potassium concentration at the end of storage and in ATP levels at the day of processing. Centrifugation temperatures of up to 34°C are well tolerated by the red blood cells with minimal interference with the RCC quality parameters. © 2013 International Society of Blood Transfusion.

  13. The Effects of Bee Venom on PLA2 and Calcium Concentration in Raw 264.7 Cells

    Directory of Open Access Journals (Sweden)

    Jong-Il Yun

    2003-06-01

    Full Text Available Objectives : The purpose of this study was to investigate the effect of Bee Venom on the lipopolysaccharide, sodium nitroprusside and hydrogen peroxide induced expression phospholipase A2 and calcium concentration in RAW 264.7 cells, a murine macrophage cell line. Methods : The expression of phospholipase A2 was determined by western blotting with corresponding antibodies, and the generation of intracellular calcium concentration was investigated by delta scan system in RAW 264.7 cells. Results : 1. Compared with control, expressions of lipopolysaccharide-induced phospholipase A2 were decreased significantly by 1 ㎍/㎕ of bee venom and decreased by 0.5, 5 ㎍/㎕ of bee venom. 2. Compared with control, expressions of sodium nitroprusside-induced phospholipase A2 were decreased significantly by 5 ㎍/㎕ of bee venom but increased by 0.5, 5 ㎍/㎕ of bee venom. 3. Compared with control, expressions of hydrogen peroxide-induced phospholipase A2 were decreased significaltly by 1 ㎍/㎕ of bee venom and decreased by 0.5 ㎍/㎕ of bee venom but increased by 5 ㎍/㎕ of bee venom. 4. Compared with control, lipopolysaccharide, sodium nitroprusside and hydrogen peroxide- induced intracellular calcium concentrations were decreased by 0.5, 1, 5 ㎍/㎕ of bee venom and by indomethacin

  14. Influences mass concentration of P3HT and PCBM to application of organic solar cells

    International Nuclear Information System (INIS)

    Supriyanto, A.; Maya; Iriani, Y.; Ramelan, A. H.; Nurosyid, F; Rosa, E. S.

    2016-01-01

    Poly (3-hexylthiophene) (P3HT) and [6, 6] -phenyl-C61-butyric acid methyl ester (PCBM) are used for the organic solar cell applications. P3HT and PCBM act as donors and acceptors, respectively. In this study the efficiency of the P3HT: PCBM organic solar cells as function of the mass concentration of the blend P3HT: PCBM with 1, 2, 8, 16 mg/ml. Deposition P3HT:PCBM film using spin coating with a rotary speed of 2500 rpm for 10 seconds. Optical properties of absorption spectra characteristic using a UV-Visible Spectrometer Lambda 25 and electrical properties of I-V characteristic using Keithley 2602 instrument. The results of absoption spectra for P3HT:PCBM within different mass concentration obtained 500-600 nm wavelengths. The Energy-gap obtained about 1.9eV. The organic solar cells device performance were investigated using I-V cahractyeristic. For mass concentration of 1, 2, 8 and 16 mg/ml P3HT:PCBM were obtained 0.5×10"-"3%, 2.2×10"-"3%, 5.9×10"-"3%, and 6.1×10"-"3% efficiency of organics solar cells respectively. (paper)

  15. Solar concentrator modules with silicone-onglass Fresnel lens panels and multijunction cells.

    Science.gov (United States)

    Rumyantsev, Valery D

    2010-04-26

    High-efficiency multijunction (MJ) solar cells, being very expensive to manufacture, should only be used in combination with solar concentrators in terrestrial applications. An essential cost reduction of electric power produced by photovoltaic (PV) installations with MJ cells, may be expected by the creation of highly-effective, but inexpensive, elements for optical concentration and sun tracking. This article is an overview of the corresponding approach under development at the Ioffe Physical Technical Institute. The approach to R&D of the solar PV modules is based on the concepts of sunlight concentration by small-aperture area Fresnel lenses and "all-glass" module design. The small-aperture area lenses are arranged as a panel with silicone-on-glass structure where the glass plate serves as the front surface of a module. In turn, high-efficiency InGaP/(In)GaAs/Ge cells are arranged on a rear module panel mounted on a glass plate which functions as a heat sink and integrated protective cover for the cells. The developed PV modules and sun trackers are characterized by simple design, and are regarded as the prototypes for further commercialization.

  16. Solar concentrator modules with silicone-on-glass Fresnel lens panels and multijunction cells.

    Science.gov (United States)

    Rumyantsev, Valery D

    2010-04-26

    High-efficiency multijunction (MJ) solar cells, being very expensive to manufacture, should only be used in combination with solar concentrators in terrestrial applications. An essential cost reduction of electric power produced by photovoltaic (PV) installations with MJ cells, may be expected by the creation of highly-effective, but inexpensive, elements for optical concentration and sun tracking. This article is an overview of the corresponding approach under development at the Ioffe Physical Technical Institute. The approach to R&D of the solar PV modules is based on the concepts of sunlight concentration by small-aperture area Fresnel lenses and "all-glass" module design. The small-aperture area lenses are arranged as a panel with silicone-on-glass structure where the glass plate serves as the front surface of a module. In turn, high-efficiency InGaP/(In)GaAs/Ge cells are arranged on a rear module panel mounted on a glass plate which functions as a heat sink and integrated protective cover for the cells. The developed PV modules and sun trackers are characterized by simple design, and are regarded as the prototypes for further commercialization.

  17. Biological effects of tritium on fish cells in the concentration range of international drinking water standards.

    Science.gov (United States)

    Stuart, Marilyne; Festarini, Amy; Schleicher, Krista; Tan, Elizabeth; Kim, Sang Bog; Wen, Kendall; Gawlik, Jilian; Ulsh, Brant

    2016-10-01

    To evaluate whether the current Canadian tritium drinking water limit is protective of aquatic biota, an in vitro study was designed to assess the biological effects of low concentrations of tritium, similar to what would typically be found near a Canadian nuclear power station, and higher concentrations spanning the range of international tritium drinking water standards. Channel catfish peripheral blood B-lymphoblast and fathead minnow testis cells were exposed to 10-100,000 Bq l(-1) of tritium, after which eight molecular and cellular endpoints were assessed. Increased numbers of DNA strand breaks were observed and ATP levels were increased. There were no increases in γH2AX-mediated DNA repair. No differences in cell growth were noted. Exposure to the lowest concentrations of tritium were associated with a modest increase in the viability of fathead minnow testicular cells. Using the micronucleus assay, an adaptive response was observed in catfish B-lymphoblasts. Using molecular endpoints, biological responses to tritium in the range of Canadian and international drinking water standards were observed. At the cellular level, no detrimental effects were noted on growth or cycling, and protective effects were observed as an increase in cell viability and an induced resistance to a large challenge dose.

  18. Bactericidal concentrations of methylglyoxal produced by heated cells of Streptococcus faecalis.

    Science.gov (United States)

    Payne, J; Hilton, M G; Gooch, J E

    1981-01-01

    Cells of Streptococcus faecalis that survived heating for 21 min at 60 degrees C were killed when resuspended at an initial cell density of about 1 X 10(8) viable units/mL and incubated at 33 degrees C for 24 h in a no-growth medium containing potassium phosphate buffer, pH 7.1, glucose, and casein hydrolysate. When such heated cells were resuspended at an initial cell density of about 1 X 10(7) viable units/mL or lower, subsequent cell death was reduced at least 10 000-fold. Unheated cells incubated under similar conditions at about 1 X 10(8) and 1 X 10(9) viable units/mL did not die. Cell death was due to a toxic compound synthesized by the heated cells, and supernatants from incubations showing a bactericidal effect contained a component, absent in nonlethal supernatants, that reacted with 2,4-dinitrophenylhydrazine. Thin-layer chromatography, mass spectrometer analysis, and the visible spectrum of the 2,4-dinitrophenylhydrazine derivative of the unknown and authentic methylglyoxal, and the positive response shown by the free unknown compound when used as a substrate for glyoxalase I, suggested that methylglyoxal was the bactericidal compound. Solutions of authentic methylglyoxal were bactericidal at concentrations above 0.2 mM and lethal supernatants contained about 1 mM methylglyoxal, whereas supernatants that were not lethal contained less than 0.02 mM methylglyoxal.

  19. Field experience and performance evaluation of a medium-concentration CPV system

    Science.gov (United States)

    Norton, Matthew; Bentley, Roger; Georghiou, George E.; Chonavel, Sylvain; De Mutiis, Alfredo

    2012-10-01

    With the aim of gaining experience and performance data from location with a harsh summer climate, a 70 X concentrating photovoltaic (CPV) system was installed in Janurary 2009 in Nicosia, Cyprus. The performance of this system has been monitored using regular current-voltage characterisations for three years. Over this period, the output of the system has remained fairly constant. Measured performance ratios varied from 0.79 to 0.86 in the winter, but fell to 0.64 over the year when left uncleaned. Operating cell temperatures were modeled and found to be similar to those of flat plate modules. The most significant causes of energy loss have been identified as originating from tracking issues and soiling. Losses due to soiling could account for a drop in output of 0.2% per day. When cleaned and properly oriented, the normalized output of the system has remained constant, suggesting that this particular design is tolerant to the physical strain of long-term outdoor exposure in harsh summer conditions. Regular cleaning and reliable tracker operation are shown to be essential for maximizing energy yield.

  20. THE STRUCTURE AND CONCENTRATION OF SOLIDS IN PHOTORECEPTOR CELLS STUDIED BY REFRACTOMETRY AND INTERFERENCE MICROSCOPY

    Science.gov (United States)

    Sidman, Richard L.

    1957-01-01

    Fragments of freshly obtained retinas of several vertebrate species were studied by refractometry, with reference to the structure of the rods and cones. The findings allowed a reassessment of previous descriptions based mainly on fixed material. The refractometric method was used also to measure the refractice indices and to calculate the concentrations of solids and water in the various cell segments. The main quantitative data were confirmed by interference microscopy. When examined by the method of refractometry the outer segments of freshly prepared retinal rods appear homogeneous. Within a few minutes a single eccentric longitudinal fiber appears, and transverse striations may develop. These changes are attributed to imbibition of water and swelling in structures normally too small for detection by light microscopy. The central "core" of outer segments and the chromophobic disc between outer and inner segments appear to be artifacts resulting from shrinkage during dehydration. The fresh outer segments of cones, and the inner segments of rods and cones also are described and illustrated. The volumes, refractive indices, concentrations of solids, and wet and dry weights of various segments of the photoreceptor cells were tabulated. Rod outer segments of the different species vary more than 100-fold in volume and mass but all have concentrations of solids of 40 to 43 per cent. Cone outer segments contain only about 30 per cent solids. The myoids, paraboloids, and ellipsoids of the inner segments likewise have characteristic refractive indices and concentrations of solids. Some of the limitations and particular virtues of refractometry as a method for quantitative analysis of living cells are discussed in comparison with more conventional biochemical techniques. Also the shapes and refractive indices of the various segments of photoreceptor cells are considered in relation to the absorption and transmission of light. The Stiles-Crawford effect can be accounted

  1. Experimental procedures for the calibration of scintillation cells used in the determination of radon gas concentrations

    International Nuclear Information System (INIS)

    Grenier, M; Bigu, J.

    1982-02-01

    Experimental and analytical procedures are described for the calibration of scintillation cells used for the determination of radon gas concentration. In-house designed and built scintillation cells, used routinely in the monitoring of radon gas in uranium mine underground environments and in the laboratory, were calibrated. The cells had a volume of approximately 158 cm 3 and an α-counting efficiency ranging from 50% to 64%. Calibration factors for the cells were determined. Values ranged approximately from 0.177 cpm/pCiL -1 (4.77 cpm/BqL -1 ) to 0.224 cpm/pCiL -1 (6.05 cpm/BqL -1 ). The calibration facilities at the Elliot Lake Laboratory are briefly described

  2. Unsteady optical and thermal behaviour of crossed compound parabolic concentrator with solar cell

    OpenAIRE

    Li, Wenguang; Paul, Manosh C.; Sellami, Nazmi; Mallick, Tapas K.; Knox, Andrew R.

    2015-01-01

    In reality, a solar panel with concentrator is\\ud subject to variable sunlight radiation, wind\\ud speed and environmental air temperature in a\\ud day, accordingly the solar output power is\\ud changed in a wide range of 2W-13W, causing\\ud a degraded electric performance [1-3]. Thus it\\ud is necessary to characterise optical and\\ud thermal behaviour of a crossed compound\\ud parabolic concentrator (CCPC) with solar cell\\ud in its design stage to optimise its configuration.\\ud Presently, the CCPC...

  3. Estimation of CO concentration in high temperature PEM fuel cells using electrochemical impedance

    DEFF Research Database (Denmark)

    Jensen, Hans-Christian Becker; Andreasen, Søren Juhl; Kær, Søren Knudsen

    2013-01-01

    Storing electrical energy is one of the main challenges for modern society grid systems containing increasing amounts of renewable energy from wind, solar and wave sources. Although batteries are excellent storage devices for electrical energy, their usage is often limited by a low energy density......) fuel cells can eciently run on the reformed hydrogen rich gas, although with reduced performance depending on the contaminants, such as CO, in the gas. By estimating the amount of CO in the fuel cell, it could be possible to adjust the fuel cell system operating parameters to increase performance...

  4. Induced Pluripotent Stem Cell-Derived Red Blood Cells and Platelet Concentrates: From Bench to Bedside

    Directory of Open Access Journals (Sweden)

    Daniele Focosi

    2017-12-01

    Full Text Available Red blood cells and platelets are anucleate blood components indispensable for oxygen delivery and hemostasis, respectively. Derivation of these blood elements from induced pluripotent stem (iPS cells has the potential to develop blood donor-independent and genetic manipulation-prone products to complement or replace current transfusion banking, also minimizing the risk of alloimmunization. While the production of erythrocytes from iPS cells has challenges to overcome, such as differentiation into adult-type phenotype that functions properly after transfusion, platelet products are qualitatively and quantitatively approaching a clinically-applicable level owing to advances in expandable megakaryocyte (MK lines, platelet-producing bioreactors, and novel reagents. Guidelines that assure the quality of iPS cells-derived blood products for clinical application represent a novel challenge for regulatory agencies. Considering the minimal risk of tumorigenicity and the expected significant demand of such products, ex vivo production of iPS-derived blood components can pave the way for iPS translation into the clinic.

  5. Induced Pluripotent Stem Cell-Derived Red Blood Cells and Platelet Concentrates: From Bench to Bedside.

    Science.gov (United States)

    Focosi, Daniele; Amabile, Giovanni

    2017-12-27

    Red blood cells and platelets are anucleate blood components indispensable for oxygen delivery and hemostasis, respectively. Derivation of these blood elements from induced pluripotent stem (iPS) cells has the potential to develop blood donor-independent and genetic manipulation-prone products to complement or replace current transfusion banking, also minimizing the risk of alloimmunization. While the production of erythrocytes from iPS cells has challenges to overcome, such as differentiation into adult-type phenotype that functions properly after transfusion, platelet products are qualitatively and quantitatively approaching a clinically-applicable level owing to advances in expandable megakaryocyte (MK) lines, platelet-producing bioreactors, and novel reagents. Guidelines that assure the quality of iPS cells-derived blood products for clinical application represent a novel challenge for regulatory agencies. Considering the minimal risk of tumorigenicity and the expected significant demand of such products, ex vivo production of iPS-derived blood components can pave the way for iPS translation into the clinic.

  6. Innovative High Temperature Fuel Cell systems

    NARCIS (Netherlands)

    Au, Siu Fai

    2003-01-01

    The world's energy consumption is growing extremely rapidly. Fuel cell systems are of interest by researchers and industry as the more efficient alternative to conventional thermal systems for power generation. The principle of fuel cell conversion does not involve thermal combustion and hence in

  7. A new one-platform flow cytometric method for residual cell counting in platelet concentrates.

    Science.gov (United States)

    Schmidt, Michael; Spengler, Hans-Peter; Lambrecht, Bernd; Hourfar, Michael K; Seifried, Erhard; Tonn, Torsten

    2009-12-01

    According to German regulations and guidelines, residual red blood cells (rRBCs) and residual white blood cells (rWBCs) must number fewer than 3 x 10(9) cells/unit and 1 x 10(6) cells/unit in platelet concentrates (PCs), respectively. Due to low levels of residual cells in final products, there is still a need for fast, reliable, and sensitive methods of automated detection of these cell types. In Part A, 21 PCs were spiked with predetermined numbers of red blood cells (RBCs) and white blood cells (WBCs). The linearity, precision, and accuracy of the BD Thrombo Count assay (BD Biosciences Europe) were tested and validated according to international guidelines. Finally in Part B, 100 PCs prepared from pooled buffy coats were tested by the BD Thrombo Count assay and compared with other methods, including Nageotte (rWBCs) and Neubauer (rRBCs) counting chambers and the flow cytometric BD LeucoCOUNT (Becton Dickinson) assay (rWBCs). The unspecific background of blank PC samples was fewer than 0.02 cells/microL for WBCs and fewer than 34 cells/microL for RBCs (mean, 21). Linear regression and precision analyses of spiked PC samples were determined for both WBCs (r(2) = 0.992; range, 0.6-6.0 WBCs/microL) and RBCs (r(2) = 0.999; 800-8000 RBCs/microL). No carryover of cells or drift in results was detected in the automated sample acquisition mode. Analysis according to statistical methods of Bland and Altman demonstrated a high correlation between BD Thrombo Count and the Neubauer manual counting chamber. This novel flow cytometric test is a quick and reliable single-tube assay that has been demonstrated as a potential alternative for the existing manual microscopic counting procedures that are both time-consuming and laborious.

  8. Spontaneous oscillations of cell voltage, power density, and anode exit CO concentration in a PEM fuel cell.

    Science.gov (United States)

    Lu, Hui; Rihko-Struckmann, Liisa; Sundmacher, Kai

    2011-10-28

    The spontaneous oscillations of the cell voltage and output power density of a PEMFC (with PtRu/C anode) using CO-containing H(2) streams as anodic fuels have been observed during galvanostatic operating. It is ascribed to the dynamic coupling of the CO adsorption (poisoning) and the electrochemical CO oxidation (reactivating) processes in the anode chamber of the single PEMFC. Accompanying the cell voltage and power density oscillations, the discrete CO concentration oscillations at the anode outlet of the PEMFC were also detected, which directly confirms the electrochemical CO oxidation taking place in the anode chamber during galvanostatic operating. This journal is © the Owner Societies 2011

  9. Nanoporous separator and low fuel concentration to minimize crossover in direct methanol laminar flow fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Hollinger, A.S. [Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, 1206 Green Street, Urbana, IL 61801 (United States); Maloney, R.J.; Jayashree, R.S. [Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, 600 S. Matthews Avenue, Urbana, IL 61801 (United States); Natarajan, D.; Markoski, L.J. [INI Power Systems, 175 Southport Drive, Suite 100, Morrisville, NC 27560 (United States); Kenis, P.J.A. [Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, 1206 Green Street, Urbana, IL 61801 (United States); Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, 600 S. Matthews Avenue, Urbana, IL 61801 (United States)

    2010-06-01

    Laminar flow fuel cells (LFFCs) overcome some key issues - most notably fuel crossover and water management - that typically hamper conventional polymer electrolyte-based fuel cells. Here we report two methods to further minimize fuel crossover in LFFCs: (i) reducing the cross-sectional area between the fuel and electrolyte streams, and (ii) reducing the driving force of fuel crossover, i.e. the fuel concentration gradient. First, we integrated a nanoporous tracketch separator at the interface of the fuel and electrolyte streams in a single-channel LFFC to dramatically reduce the cross-sectional area across which methanol can diffuse. Maximum power densities of 48 and 70 mW cm{sup -2} were obtained without and with a separator, respectively, when using 1 M methanol. This simple design improvement reduces losses at the cathode leading to better performance and enables thinner cells, which is attractive in portable applications. Second, we demonstrated a multichannel cell that utilizes low methanol concentrations (<300 mM) to reduce the driving force for methanol diffusion to the cathode. Using 125 mM methanol as the fuel, a maximum power density of 90 mW cm{sup -2} was obtained. This multichannel cell further simplifies the LFFC design (one stream only) and its operation, thereby extending its potential for commercial application. (author)

  10. Measurement of the mechanical properties of single Synechocystis sp. strain PCC6803 cells in different osmotic concentrations using a robot-integrated microfluidic chip.

    Science.gov (United States)

    Chang, Di; Sakuma, Shinya; Kera, Kota; Uozumi, Nobuyuki; Arai, Fumihito

    2018-03-23

    Synechocystis sp. strain PCC6803 (Synechocystis) is a model microorganism and its mechanosensitive (MS) channels play important roles in its osmoadaptation mechanism. When the osmotic concentration of the culture environment changes, the inner pressure of the cell also changes due to the transportation of water through ion channels. Because the tension in the cell membrane relates to the inner pressure, we expect that the response of the MS channels to an osmotic concentration change could be evaluated by measuring their mechanical properties. Here, we propose a system for the measurement of the mechanical properties of a single Synechocystis cell. We developed a robot-integrated microfluidic chip combined with optical tweezers. The chip has an external actuated pushing probe and a force sensor probe. A single cell was located between the tip of both probes using the optical tweezers and was then deformed using the probes. As a result, we could measure the force and deformation and compare the Young's moduli of two groups: a group of wild type cells and a group of mutant (genetically modified) cells with a defect in the MS channels, at three different osmotic concentrations. The results showed that the Young's modulus of each group changed according to the osmotic concentration, while changes in cell size were too small to be detected. These results confirmed that the proposed evaluation method provides an understanding of the physiological function of MS channels for keeping the cell integrity of microorganisms when the cells are exposed to different external osmotic changes.

  11. Short-term effects of ultrahigh concentration cationic silica nanoparticles on cell internalization, cytotoxicity, and cell integrity with human breast cancer cell line (MCF-7)

    Energy Technology Data Exchange (ETDEWEB)

    Seog, Ji Hyun [Korea Advanced Institute of Science and Technology, Graduate School of Nanoscience and Technology (Korea, Republic of); Kong, Bokyung [Corning Precision Materials (Korea, Republic of); Kim, Dongheun [Korea Advanced Institute of Science and Technology, Graduate School of Nanoscience and Technology (Korea, Republic of); Graham, Lauren M. [University of Maryland, Department of Chemistry and Biochemistry (United States); Choi, Joon Sig [Chungnam National University, Department of Biochemistry (Korea, Republic of); Lee, Sang Bok, E-mail: slee@umd.edu [Korea Advanced Institute of Science and Technology, Graduate School of Nanoscience and Technology (Korea, Republic of)

    2015-01-15

    High concentrations of cationic colloidal silica nanoparticles (CCS-NPs) have been widely used for the enrichment of plasma membrane proteins. However, the interaction between the CCS-NPs and cells under the required concentration for the isolation of plasma membrane are rarely investigated. We evaluated the internalization and toxicity of the 15 nm CCS-NPs which were exposed at high concentrations with short time in human breast cancer cells (MCF-7) with transmission electron microscopy, energy dispersive X-ray spectroscopy, inductively coupled plasma atomic emission spectroscopy, and colorimetric assays. The NPs were observed throughout the cells, particularly in the cytoplasm and the nucleus, after short incubation periods. Additionally, the NPs significantly influenced the membrane integrity of the MCF-7 cells.

  12. Cancer stem cells of the digestive system.

    Science.gov (United States)

    Colvin, Hugh S; Nishida, Naohiro; Koseki, Jun; Konno, Masamitsu; Kawamoto, Koichi; Tsunekuni, Kenta; Doki, Yuichiro; Mori, Masaki; Ishii, Hideshi

    2014-12-01

    Stem cells of the digestive system are ideal in many ways for research, given they are abundant, highly proliferative and have a uniform structural arrangement. This in turn has enormously aided the research of cancer stem cells of the digestive system, which is now shaping our understanding of cancer stem cells. In this review, the recent advances in the understanding of cancer stem cells of the digestive system have been summarized, including aspects such as their identification, origin, cell-cycle dormancy, relationship with epithelial-mesenchymal transition, cellular metabolism and the underlying molecular mechanisms. Newly acquired knowledge concerning cancer stem cells have led to the development of novel cancer therapeutics with provisional yet encouraging results. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  13. [Biologic effects of different concentrations of putrescine on human umbilical vein endothelial cells].

    Science.gov (United States)

    Chen, Jianxia; Rong, Xinzhou; Fan, Guicheng; Li, Songze; Zhang, Tao; Li, Qinghui

    2015-12-01

    To explore the effects of different concentrations of putrescine on proliferation, migration, and apoptosis of human umbilical vein endothelial cells (HUVECs). HUVECs were routinely cultured in vitro. The 3rd to the 5th passage of HUVECs were used in the following experiments. (1) Cells were divided into 500, 1 000, and 5 000 µg/mL putrescine groups according to the random number table (the same grouping method was used for following grouping), with 3 wells in each group, which were respectively cultured with complete culture solution containing putrescine in the corresponding concentration for 24 h. Morphology of cells was observed by inverted optical microscope. (2) Cells were divided into 0.5, 1.0, 5.0, 10.0, 50.0, 100.0, 500.0, 1 000.0 µg/mL putrescine groups, and control group, with 4 wells in each group. Cells in the putrescine groups were respectively cultured with complete culture solution containing putrescine in the corresponding concentration for 24 h, and cells in control group were cultured with complete culture solution with no additional putrescine for 24 h. Cell proliferation activity (denoted as absorption value) was measured by colorimetry. (3) Cells were divided (with one well in each group) and cultured as in experiment (2), and the migration ability was detected by transwell migration assay. (4) Cells were divided (with one flask in each group) and cultured as in experiment (2), and the cell apoptosis rate was determined by flow cytometer. Data were processed with one-way analysis of variance, Kruskal-Wallis test, and Dunnett test. (1) After 24-h culture, cell attachment was good in 500 µg/mL putrescine group, and no obvious change in the shape was observed; cell attachment was less in 1 000 µg/mL putrescine group and the cells were small and rounded; cells in 5 000 µg/mL putrescine group were in fragmentation without attachment. (2) The absorption values of cells in 0.5, 1.0, 5.0, 10.0, 50.0, 100.0, 500.0, 1 000.0 µg/mL putrescine groups

  14. Evaluation of various glyphosate concentrations on DNA damage in human Raji cells and its impact on cytotoxicity.

    Science.gov (United States)

    Townsend, Michelle; Peck, Connor; Meng, Wei; Heaton, Matthew; Robison, Richard; O'Neill, Kim

    2017-04-01

    Glyphosate is a highly used active compound in agriculturally based pesticides. The literature regarding the toxicity of glyphosate to human cells has been highly inconsistent. We studied the resulting DNA damage and cytotoxicity of various glyphosate concentrations on human cells to evaluate DNA damaging potential. Utilizing human Raji cells, DNA damage was quantified using the comet assay, while cytotoxicity was further analyzed using MTT viability assays. Several glyphosate concentrations were assessed, ranging from 15 mM to 0.1 μM. We found that glyphosate treatment is lethal to Raji cells at concentrations above 10 mM, yet has no cytotoxic effects at concentrations at or below 100 μM. Treatment concentrations of 1 mM and 5 mM induce statistically significant DNA damage to Raji cells following 30-60 min of treatment, however, cells show a slow recovery from initial damage and cell viability is unaffected after 2 h. At these same concentrations, cells treated with additional compound did not recover and maintained high levels of DNA damage. While the cytotoxicity of glyphosate appears to be minimal for physiologically relevant concentrations, the compound has a definitive cytotoxic nature in human cells at high concentrations. Our data also suggests a mammalian metabolic pathway for the degradation of glyphosate may be present. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Measurement of plasma cell-free DNA concentrations in dogs with sepsis, trauma, and neoplasia.

    Science.gov (United States)

    Letendre, Jo-Annie; Goggs, Robert

    2017-05-01

    To determine if cell-free DNA (cfDNA) was identifiable in canine plasma, to evaluate 3 techniques for the measurement of plasma cfDNA concentrations in dogs presented to an emergency service, and to compare the plasma cfDNA concentrations of healthy dogs to those with sepsis, trauma, and neoplasia. Retrospective study of banked canine plasma samples collected between May 2014 and December 2014. Dogs presented to the emergency service of a university veterinary teaching hospital. Plasma cfDNA was measured on residual plasma samples obtained from 15 dogs with sepsis, 15 dogs with moderate-severe trauma, 15 dogs diagnosed with a sarcoma. Plasma cfDNA was also measured in 15 healthy dogs. None. Assay linearity, repeatability, and reproducibility were evaluated. Quantification of cfDNA was performed in duplicate on diluted citrated plasma and following DNA purification using 2 fluorescence assays (SYBR-Gold; Quant-iT) and by ultraviolet absorbance spectroscopy. Fluorescence intensities (FIs) were converted to cfDNA concentrations using standard curves. Median FI values and cfDNA concentrations were compared to healthy controls using the Kruskal-Wallis test, with adjustment for multiple comparisons. Alpha was set at 0.05. Both assays had excellent linearity, and acceptable repeatability and reproducibility. Compared to controls, plasma cfDNA concentrations were significantly increased in dogs with sepsis or moderate-severe trauma with both assays (P ≤ 0.003). Dogs with neoplasia had significantly increased cfDNA concentrations with the Quant-iT assay only (P = 0.003). When measurements were performed on purified DNA, only dogs with moderate-severe trauma had significantly increased cfDNA concentrations (P plasma using 2 fluorescence assays. DNA extraction offers no advantage over direct measurement. Compared to healthy controls, dogs with sepsis or moderate-severe trauma have significantly increased plasma cfDNA concentrations. © Veterinary Emergency and Critical Care

  16. Ketamine Metabolites Enantioselectively Decrease Intracellular D-Serine Concentrations in PC-12 Cells.

    Directory of Open Access Journals (Sweden)

    Nagendra S Singh

    Full Text Available D-Serine is an endogenous NMDA receptor co-agonist that activates synaptic NMDA receptors modulating neuronal networks in the cerebral cortex and plays a key role in long-term potentiation of synaptic transmission. D-serine is associated with NMDA receptor neurotoxicity and neurodegeneration and elevated D-serine concentrations have been associated with Alzheimer's and Parkinsons' diseases and amyotrophic lateral sclerosis. Previous studies have demonstrated that the ketamine metabolites (rac-dehydronorketamine and (2S,6S-hydroxynorketamine decrease intracellular D-serine concentrations in a concentration dependent manner in PC-12 cells. In the current study, PC-12 cells were incubated with a series of ketamine metabolites and the IC50 values associated with attenuated intracellular D-serine concentrations were determined. The results demonstrate that structural and stereochemical features of the studied compounds contribute to the magnitude of the inhibitory effect with (2S,6S-hydroxynorketamine and (2R,6R-hydroxynorketamine displaying the most potent inhibition with IC50 values of 0.18 ± 0.04 nM and 0.68 ± 0.09 nM. The data was utilized to construct a preliminary 3D-QSAR/pharmacophore model for use in the design of new and more efficient modulators of D-serine.

  17. Determination of blood cell subtype concentrations from frozen whole blood samples using TruCount beads.

    Science.gov (United States)

    Langenskiöld, Cecilia; Mellgren, Karin; Abrahamsson, Jonas; Bemark, Mats

    2016-06-24

    In many studies it would be advantageous if blood samples could be collected and analyzed using flow cytometry at a later stage. Ideally, sample collection should involve little hands-on time, allow for long-term storage, and minimally influence the samples. Here we establish a flow cytometry antibody panel that can be used to determine granulocytes, monocytes, and lymphocyte subset concentrations in fresh and frozen whole blood using TruCount technology. The panel can be used on fresh whole-blood samples as well as whole-blood samples that have been frozen after mixing with 10% DMSO. Concentrations in frozen and fresh sample is highly correlated both when frozen within 4 h and the day after collection (r ≥ 0.98), and the estimated concentration in frozen samples was between 91 and 94% of that in fresh samples for all cell types. Using this method whole-blood samples can be frozen using a simple preparation method, and stored long-term before accurate determination of cell concentration. This allows for standardized analysis of the samples at a reference laboratory in multi-center studies. © 2016 International Clinical Cytometry Society. © 2016 International Clinical Cytometry Society.

  18. Harvest impacts on alfalfa stem neutral detergent fiber concentration and digestibility and cell wall concentration and composition

    Science.gov (United States)

    Alfalfa (Medicago sativa L.) stem fiber concentration and digestibility, lignin, and polysaccharide composition impact energy availability for livestock and biofuel conversion efficiency and are affected by maturity stage and environmental influences. We evaluated stem neutral detergent fiber (NDF) ...

  19. Feasibility and parametric evaluation of hybrid concentrated photovoltaic-thermoelectric system

    DEFF Research Database (Denmark)

    Rezaniakolaei, Alireza; Rosendahl, Lasse Aistrup

    2017-01-01

    Concentrated photovoltaic (CPV) system integrated with thermoelectric generators (TEGs) is a novel technology that has potential to offer high efficient system. In this study, a thermally coupled model of concentrated photovoltaic-thermoelctric (CPV/TEG) system is established to investigate...... feasibility of the hybrid system over wide range of solar concentrations and different types of heat sinks. The model takes into account critical design parameters in the CPV and the TEG module. The results of this study show that for thermoelectric materials with ZT ≈ 1, the CPV/TEG system is more efficient...... than CPV-only system. The results indicate that contribution of the TEG in power generation enhances at high sun concentrations. Depending to critical design parameters of the CPV and the TEG, there are optimal values for heat transfer coefficient in the heat sink that offer minimum energy cost....

  20. Fuel cell systems and production aspects

    Energy Technology Data Exchange (ETDEWEB)

    Blomen, L.J.M.J. [Blomenco, Rumpt (Netherlands)

    1995-02-01

    Attention is paid to some system integration and production aspects of fuel cell systems. After an introduction of the main performance differences of fuel cell systems with different types of fuel cells, and the causes for such differences, a few aspects of building up sub-systems towards large and small capacity fuel cell systems are being discussed. Subsequently, some production aspects are being highlighted: the concept of an automated plant and automated plant contracting, the trends towards greater simplicity m reactors, and a systematic evaluation of the differences in fuel processing steps required in systems with different types of fuel cells. In this section also the cost aspects of a total plant contracting project are being discussed. As a next step, some emphasis has been placed on system integration aspects, explaining that hydrogen purification does not always `destroy` system efficiency, and can be used in dispersed hydrogen generation concepts. Advanced system integration concepts include simplified flow sheet design, in which instead of special dedicated rotating equipment standard gas turbine rotary components are being employed. As an example, it is claimed that gas turbine - fuel cell combinations can be made with very high electrical efficiencies. 5 figs., 2 tabs.

  1. Water reactive hydrogen fuel cell power system

    Science.gov (United States)

    Wallace, Andrew P; Melack, John M; Lefenfeld, Michael

    2014-01-21

    A water reactive hydrogen fueled power system includes devices and methods to combine reactant fuel materials and aqueous solutions to generate hydrogen. The generated hydrogen is converted in a fuel cell to provide electricity. The water reactive hydrogen fueled power system includes a fuel cell, a water feed tray, and a fuel cartridge to generate power for portable power electronics. The removable fuel cartridge is encompassed by the water feed tray and fuel cell. The water feed tray is refillable with water by a user. The water is then transferred from the water feed tray into a fuel cartridge to generate hydrogen for the fuel cell which then produces power for the user.

  2. A novel solar trigeneration system based on concentrating photovoltaic/thermal collectors. Part 1: Design and simulation model

    International Nuclear Information System (INIS)

    Buonomano, Annamaria; Calise, Francesco; Dentice d'Accadia, Massimo; Vanoli, Laura

    2013-01-01

    This paper analyzes the thermodynamic performance of high-temperature PhotoVoltaic/Thermal (PVT) solar collectors. The collector is based on a combination of a parabolic dish concentrating solar thermal collector and a high efficiency solar photovoltaic collector. The PVT system under investigation allows one to produce simultaneously electrical energy and high-temperature thermal energy by solar irradiation. The main aim of this study is the design and the analysis of a concentrating PVT which is able to operate at reasonable electric and thermal efficiency up to 180 °C. In fact, the PVT is designed to be integrated in a Solar Heating and Cooling system and it must drive a two-effect absorption chiller. This capability is quite new since conventional PVT collectors usually operate below 45 °C. Among the possible high-temperature PVT systems, this paper is focused on a system consisting in a dish concentrator and in a triple-junction PV layer. In particular, the prototype consists in a parabolic dish concentrator and a planar receiver. The system is equipped with a double axis tracking system. The bottom surface of the receiver is equipped with triple-junction silicon cells whereas the top surface is insulated. In order to analyze the performance of the Concentrating PVT (CPVT) collector a detailed mathematical model was implemented. This model is based on zero-dimensional energy balances on the control volumes of the system. The simulation model allows one to calculate in detail the temperatures of the main components of the system (PV layer, concentrator, fluid inlet and outlet and metallic substrate) and the main energy flows (electrical energy, useful thermal energy, radiative losses, convective losses). The input parameters of the model include all the weather conditions (temperature, insolation, wind velocity, etc.) and the geometrical/material parameters of the systems (lengths, thermal resistances, thicknesses, etc.). Results showed that both electrical

  3. The development and test of the PV concentrator system with electrical and thermal output

    Science.gov (United States)

    Okhorzina, A.; Kshalova, A.

    2017-08-01

    The article presents the control system of the PV concentrator system cooled by a heat sink. The installation is a hybrid system that generates heat and electrical energy from sunlight. The installation consists of a concentrator, photovoltaic modules and their cooling systems. It is necessary to control each part of the System to make it work effectively and get the highest amount of energy from it. The control system consists of subsystems, which control the sun tracking, cooling and the photovoltaic modules with accumulators.

  4. [Effects of grape procyanidins on the concentration of intracellular calcium and the proliferation activity of the hepatoma cells].

    Science.gov (United States)

    Zhong, Jin-Yi; Li, Jie; Liu, Hui; Zhang, She-Hua

    2006-09-01

    To investigate the effects of grape procyanidins (GPC) on concentration of intracellular calcium and the proliferation activity of normal hepatic cells and the hepatic cell injuried by alcohol. Rat hepatic cells and the cell injuried by alcohol were cultured with different concentration of GPC. The proliferation activity and concentration of intracellular calcium of the hepatic cells were measured by MTT assay and Fura-2 fluorescence methods. (1) The concentration of intracellular calcium of the normal control group and alcohol injury group were (108.26 +/- 14.17) and (651.24 +/- 47.95) nmol/L respectively, and that of both the high and the medium dose GPC groups were lower than the alcohol injury group, all differences are significant (P calcium in the normal hepatic cells treated with GPC is the group with calcium of extracellular fluid > the group free from calcium of extracellular fluid > the normal control group. (3) The proliferation activity of the high and the medium dose GPC group of normal hepatic cell and the cell injuried by alcohol were higher than the normal control group and alcohol injury group, all differences are significant (P calcium concentration of normal hepatic cell by increasing extracellular fluidca introaffluxion and release from calcium pool, and enhance the proliferation activity of hepatic cells. It also can inhibit the abnormal rise (overload) of intracellular calcium concentration and the proliferation activity injury of hepatic cell induced by alcohol.

  5. Preservation of high glycolytic phenotype by establishing new acute lymphoblastic leukemia cell lines at physiologic oxygen concentration

    International Nuclear Information System (INIS)

    Sheard, Michael A.; Ghent, Matthew V.; Cabral, Daniel J.; Lee, Joanne C.; Khankaldyyan, Vazgen; Ji, Lingyun; Wu, Samuel Q.; Kang, Min H.

    2015-01-01

    Cancer cells typically exhibit increased glycolysis and decreased mitochondrial oxidative phosphorylation, and they continue to exhibit some elevation in glycolysis even under aerobic conditions. However, it is unclear whether cancer cell lines employ a high level of glycolysis comparable to that of the original cancers from which they were derived, even if their culture conditions are changed to physiologically relevant oxygen concentrations. From three childhood acute lymphoblastic leukemia (ALL) patients we established three new pairs of cell lines in both atmospheric (20%) and physiologic (bone marrow level, 5%) oxygen concentrations. Cell lines established in 20% oxygen exhibited lower proliferation, survival, expression of glycolysis genes, glucose consumption, and lactate production. Interestingly, the effects of oxygen concentration used during cell line initiation were only partially reversible when established cell cultures were switched from one oxygen concentration to another for eight weeks. These observations indicate that ALL cell lines established at atmospheric oxygen concentration can exhibit relatively low levels of glycolysis and these levels are semi-permanent, suggesting that physiologic oxygen concentrations may be needed from the time of cell line initiation to preserve the high level of glycolysis commonly exhibited by leukemias in vivo. - Highlights: • Establishing new ALL cell lines in 5% oxygen resulted in higher glycolytic expression and function. • Establishing new ALL cell lines in 5% oxygen resulted in higher proliferation and lower cell death. • The divergent metabolic phenotypes selected in 5% and 20% oxygen are semi-permanent

  6. Preservation of high glycolytic phenotype by establishing new acute lymphoblastic leukemia cell lines at physiologic oxygen concentration

    Energy Technology Data Exchange (ETDEWEB)

    Sheard, Michael A., E-mail: msheard@chla.usc.edu [Developmental Therapeutics Program, USC-CHLA Institute for Pediatric Clinical Research, Division of Hematology-Oncology, Children' s Hospital Los Angeles, 4650 Sunset Blvd., Los Angeles, CA 90027 (United States); Ghent, Matthew V., E-mail: mattghent@gmail.com [Department of Pathology, Keck School of Medicine, University of Southern California, Health Sciences Campus, Los Angeles, CA 90089 (United States); Cabral, Daniel J., E-mail: dcabral14@gmail.com [Cancer Center and Departments of Cell Biology & Biochemistry, Pharmacology & Neuroscience, Internal Medicine and Pediatrics, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430 (United States); Lee, Joanne C., E-mail: joannebarnhart@gmail.com [Cancer Center and Departments of Cell Biology & Biochemistry, Pharmacology & Neuroscience, Internal Medicine and Pediatrics, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430 (United States); Khankaldyyan, Vazgen, E-mail: khangaldian@yahoo.com [Developmental Therapeutics Program, USC-CHLA Institute for Pediatric Clinical Research, Division of Hematology-Oncology, Children' s Hospital Los Angeles, 4650 Sunset Blvd., Los Angeles, CA 90027 (United States); Ji, Lingyun, E-mail: lingyun.ji@med.usc.edu [Developmental Therapeutics Program, USC-CHLA Institute for Pediatric Clinical Research, Division of Hematology-Oncology, Children' s Hospital Los Angeles, 4650 Sunset Blvd., Los Angeles, CA 90027 (United States); Wu, Samuel Q., E-mail: swu@chla.usc.edu [Medical Genetics, Children' s Hospital Los Angeles, 4650 Sunset Blvd., Los Angeles, CA 90027 (United States); Kang, Min H., E-mail: min.kang@ttuhsc.edu [Cancer Center and Departments of Cell Biology & Biochemistry, Pharmacology & Neuroscience, Internal Medicine and Pediatrics, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430 (United States); and others

    2015-05-15

    Cancer cells typically exhibit increased glycolysis and decreased mitochondrial oxidative phosphorylation, and they continue to exhibit some elevation in glycolysis even under aerobic conditions. However, it is unclear whether cancer cell lines employ a high level of glycolysis comparable to that of the original cancers from which they were derived, even if their culture conditions are changed to physiologically relevant oxygen concentrations. From three childhood acute lymphoblastic leukemia (ALL) patients we established three new pairs of cell lines in both atmospheric (20%) and physiologic (bone marrow level, 5%) oxygen concentrations. Cell lines established in 20% oxygen exhibited lower proliferation, survival, expression of glycolysis genes, glucose consumption, and lactate production. Interestingly, the effects of oxygen concentration used during cell line initiation were only partially reversible when established cell cultures were switched from one oxygen concentration to another for eight weeks. These observations indicate that ALL cell lines established at atmospheric oxygen concentration can exhibit relatively low levels of glycolysis and these levels are semi-permanent, suggesting that physiologic oxygen concentrations may be needed from the time of cell line initiation to preserve the high level of glycolysis commonly exhibited by leukemias in vivo. - Highlights: • Establishing new ALL cell lines in 5% oxygen resulted in higher glycolytic expression and function. • Establishing new ALL cell lines in 5% oxygen resulted in higher proliferation and lower cell death. • The divergent metabolic phenotypes selected in 5% and 20% oxygen are semi-permanent.

  7. A fluorescence anisotropy method for measuring protein concentration in complex cell culture media.

    Science.gov (United States)

    Groza, Radu Constantin; Calvet, Amandine; Ryder, Alan G

    2014-04-22

    The rapid, quantitative analysis of the complex cell culture media used in biopharmaceutical manufacturing is of critical importance. Requirements for cell culture media composition profiling, or changes in specific analyte concentrations (e.g. amino acids in the media or product protein in the bioprocess broth) often necessitate the use of complicated analytical methods and extensive sample handling. Rapid spectroscopic methods like multi-dimensional fluorescence (MDF) spectroscopy have been successfully applied for the routine determination of compositional changes in cell culture media and bioprocess broths. Quantifying macromolecules in cell culture media is a specific challenge as there is a need to implement measurements rapidly on the prepared media. However, the use of standard fluorescence spectroscopy is complicated by the emission overlap from many media components. Here, we demonstrate how combining anisotropy measurements with standard total synchronous fluorescence spectroscopy (TSFS) provides a rapid, accurate quantitation method for cell culture media. Anisotropy provides emission resolution between large and small fluorophores while TSFS provides a robust measurement space. Model cell culture media was prepared using yeastolate (2.5 mg mL(-1)) spiked with bovine serum albumin (0 to 5 mg mL(-1)). Using this method, protein emission is clearly discriminated from background yeastolate emission, allowing for accurate bovine serum albumin (BSA) quantification over a 0.1 to 4.0 mg mL(-1) range with a limit of detection (LOD) of 13.8 μg mL(-1). Copyright © 2014. Published by Elsevier B.V.

  8. Estimating changes in urban ozone concentrations due to life cycle emissions from hydrogen transportation systems

    International Nuclear Information System (INIS)

    Guihua Wang; Ogden, Joan M.; Chang, Daniel P.Y.

    2007-01-01

    Hydrogen has been proposed as a low polluting alternative transportation fuel that could help improve urban air quality. This paper examines the potential impact of introducing a hydrogen-based transportation system on urban ambient ozone concentrations. This paper considers two scenarios, where significant numbers of new hydrogen vehicles are added to a constant number of gasoline vehicles. In our scenarios hydrogen fuel cell vehicles (HFCVs) are introduced in Sacramento, California at market penetrations of 9% and 20%. From a life cycle analysis (LCA) perspective, considering all the emissions involved in producing, transporting, and using hydrogen, this research compares three hypothetical natural gas to hydrogen pathways: (1) on-site hydrogen production; (2) central hydrogen production with pipeline delivery; and (3) central hydrogen production with liquid hydrogen truck delivery. Using a regression model, this research shows that the daily maximum temperature correlates well with atmospheric ozone formation. However, increases in initial VOC and NO x concentrations do not necessarily increase the peak ozone concentration, and may even cause it to decrease. It is found that ozone formation is generally limited by NO x in the summer and is mostly limited by VOC in the fall in Sacramento. Of the three hydrogen pathways, the truck delivery pathway contributes the most to ozone precursor emissions. Ozone precursor emissions from the truck pathway at 9% market penetration can cause additional 3-h average VOC (or NO x ) concentrations up to approximately 0.05% (or 1%) of current pollution levels, and at 20% market penetration up to approximately 0.1% (or 2%) of current pollution levels. However, all of the hydrogen pathways would result in very small (either negative or positive) changes in ozone air quality. In some cases they will result in worse ozone air quality (mostly in July, August, and September), and in some cases they will result in better ozone air

  9. High-efficiency thin and compact concentrator photovoltaics with micro-solar cells directly attached to a lens array.

    Science.gov (United States)

    Hayashi, Nobuhiko; Inoue, Daijiro; Matsumoto, Mitsuhiro; Matsushita, Akio; Higuchi, Hiroshi; Aya, Youichirou; Nakagawa, Tohru

    2015-06-01

    We propose a thin and compact concentrator photovoltaic (CPV) module, about 20 mm thick, one tenth thinner than those of conventional CPVs that are widely deployed for mega-solar systems, to broaden CPV application scenarios. We achieved an energy conversion efficiency of 37.1% at a module temperature of 25 °C under sunlight irradiation optimized for our module. Our CPV module has a lens array consisting of 10 mm-square unit lenses and micro solar cells that are directly attached to the lens array, to reduce the focal length of the concentrator and to reduce optical losses due to reflection. The optical loss of the lens in our module is about 9.0%, which is lower than that of conventional CPV modules with secondary optics. This low optical loss enables our CPV module to achieve a high energy conversion efficiency.

  10. Analysis of a photovoltaic-electrolyser direct-coupling system with a V-trough concentrator

    International Nuclear Information System (INIS)

    Su, Ziyun; Ding, Shuiting; Gan, Zhiwen; Yang, Xiaoyi

    2016-01-01

    Highlights: • A V-trough concentrator is applied in PVE system. • An analysis model for the CPVE system is established and verified experimentally. • The result shows that the V-trough concentrator increases the system efficiency. • The hydrogen production of the PVE system is doubled in this investigation. - Abstract: Hydrogen is a clean energy carrier for energy storage which is essential to solar system for continuous energy output. A promising method to store solar energy as hydrogen energy is by using photovoltaic-electrolyser (PVE) system. In this investigation, the operation of a PVE system with V-trough concentrator was studied experimentally and numerically. The V-trough concentrator was optimized and the daily average concentration ratio reaches about 1.9. A mathematical model including the sub models for irradiation flux pattern, PV array and electrolyser was established to analyze the characteristics of the system and it was verified experimentally. The results show that the utilization of V-trough concentrator makes PVE system work more efficiently with the same PV array. In this study, the conversion efficiency of solar energy to hydrogen energy was increased from 5.62% to 6.18% and the hydrogen production was doubled.

  11. An Automatic Indirect Immunofluorescence Cell Segmentation System

    Directory of Open Access Journals (Sweden)

    Yung-Kuan Chan

    2014-01-01

    Full Text Available Indirect immunofluorescence (IIF with HEp-2 cells has been used for the detection of antinuclear autoantibodies (ANA in systemic autoimmune diseases. The ANA testing allows us to scan a broad range of autoantibody entities and to describe them by distinct fluorescence patterns. Automatic inspection for fluorescence patterns in an IIF image can assist physicians, without relevant experience, in making correct diagnosis. How to segment the cells from an IIF image is essential in developing an automatic inspection system for ANA testing. This paper focuses on the cell detection and segmentation; an efficient method is proposed for automatically detecting the cells with fluorescence pattern in an IIF image. Cell culture is a process in which cells grow under control. Cell counting technology plays an important role in measuring the cell density in a culture tank. Moreover, assessing medium suitability, determining population doubling times, and monitoring cell growth in cultures all require a means of quantifying cell population. The proposed method also can be used to count the cells from an image taken under a fluorescence microscope.

  12. A microfluidic-structured flow field for passive direct methanol fuel cells operating with highly concentrated fuels

    International Nuclear Information System (INIS)

    Wu, Q X; Zhao, T S; Chen, R; Yang, W W

    2010-01-01

    Conventional direct methanol fuel cells (DMFCs) have to operate with excessively diluted methanol solutions to limit methanol crossover and its detrimental consequences. Operation with such diluted methanol solutions not only results in a significant penalty in the specific energy of the power pack, limiting the runtime of this type of fuel cell, but also lowers the cell performance and operating stability. In this paper, a microfluidic-structured anode flow field for passive DMFCs with neither liquid pumps nor gas compressors/blowers is developed. This flow field consists of plural micro flow passages. Taking advantage of the liquid methanol and gas CO 2 two-phase counter flow, the unique fluidic structure enables the formation of a liquid–gas meniscus in each flow passage. The evaporation from the small meniscus in each flow passage can lead to an extremely large interfacial mass-transfer resistance, creating a bottleneck of methanol delivery to the anode CL. The fuel cell tests show that the innovative flow field allows passive DMFCs to achieve good cell performance with a methanol concentration as high as 18.0 M, increasing the specific energy of the DMFC system by about five times compared with conventional designs.

  13. Development and calibration of a portable radon sampling system for groundwater 222Rn activity concentration measurements.

    Science.gov (United States)

    Lucas, Fabio de Oliveira; de Oliveira, Igor José Chaves; Ribeiro, Fernando Brenha

    2009-10-01

    The assembling of a system for field sampling and activity concentration measurement of radon dissolved in groundwater is described. Special attention is given in presenting the calibration procedure to obtain the radon activity concentration in groundwater from the raw counting rate registered in a portable scintillation detector and in establishing the precision of the activity concentration measurements. A field procedure was established and the system tested during one year of monthly observations of (222)Rn activity concentration in groundwater drawn from two wells drilled on metamorphic rocks exposed at Eastern São Paulo State, Brazil. The observed mean (222)Rn activity concentrations are 374Bq/dm(3) in one well and about 1275Bq/dm(3) in the other one. In both wells the (222)Rn activity concentrations showed a seasonal variation similar to variations previously reported in the literature for the same region.

  14. Effect of molecular weight and concentration of hyaluronan on cell proliferation and osteogenic differentiation in vitro

    International Nuclear Information System (INIS)

    Zhao, Ningbo; Wang, Xin; Qin, Lei; Guo, Zhengze; Li, Dehua

    2015-01-01

    Hyaluronan (HA), the simplest glycosaminoglycan and a major component of the extracellular matrix, exists in various tissues. It is involved in some critical biological procedures, including cellular signaling, cell adhesion and proliferation, and cell differentiation. The effect of molecular weight (MW) and concentration of HA on cell proliferation and differentiation was controversial. In this study, we investigated the effect of MW and concentration of HA on the proliferation and osteogenic differentiation of rabbit bone marrow-derived stem cells in vitro. Results showed that high MW HA decreased the cell adhesion rate in a concentration-dependant manner. The cell adhesion rate was decreased by increasing MW of HA. Cell proliferation was significantly enhanced by low MW HA (P < 0.05). The factorial analysis indicated that MW and concentration had an interactive effect on the cell adhesion rate and cell proliferation (P < 0.05). High MW HA increased the mRNA expressions of ALP, RUNX-2 and OCN. The higher the MW was, the higher the mRNA expressions were. The factorial analysis indicated that MW and concentration had an interactive effect on ALP mRNA expression (P < 0.05). HA of higher MW and higher concentration promoted bone formation. These findings provide some useful information in understanding the mechanism underlying the effect of MW and concentration of HA on cell proliferation and differentiation. - Highlights: • Effect of hyaluronan on cell proliferation and differentiation is evaluated in vitro. • Hyaluronan of low molecular weight increases cell proliferation. • Hyaluronan of high molecular weight promotes cell osteogenic differentiation. • Molecular weight and concentration of hyaluronan show interactive effect

  15. Cell death in the cardiovascular system

    Science.gov (United States)

    Clarke, Murray; Bennett, Martin; Littlewood, Trevor

    2007-01-01

    Cell death is important for both development and tissue homeostasis in the adult. As such, it is tightly controlled and deregulation is associated with diverse pathologies; for example, regulated cell death is involved in vessel remodelling during development or following injury, but deregulated death is implicated in pathologies such as atherosclerosis, aneurysm formation, ischaemic and dilated cardiomyopathies and infarction. We describe the mechanisms of cell death and its role in the normal physiology and various pathologies of the cardiovascular system. PMID:16547202

  16. [Cell polarity in the cardiovascular system].

    Science.gov (United States)

    Haller, C; Kübler, W

    1999-05-01

    The importance of cell polarity as a fundamental biological principle is increasingly recognized in the cardiovascular system. Polar cell mechanisms underlie not only the development of the heart and blood vessels, but also play a major role in the adult organism for polarized endothelial functions such as the separation of the intra- and extravascular compartment and the vectorial exchange of substances between these compartments. Endothelial cells are connected through intercellular junctions which separate the functionally and structurally distinct luminal and abluminal cell surfaces. The luminal plasma membrane is in contact with the blood and takes part in the regulation of hemostasis. The abluminal cell membrane connects the endothelial cell with the basement membrane and modulates blood flow through the release of vasoactive substances. Results from epithelial model systems have shown that the polarized cell phenotype is generated by specific protein sorting and regulated protein trafficking between the trans-Golgi network and the cell surface. The polarized distribution of cell membrane proteins is maintained by anchorage with the cytoskeleton and limitation of lateral diffusion by tight junctions. Disturbances of cell polarity may contribute to the pathogenesis of disease states, including ischemic and radiocontrast-induced acute renal failure and carcinomas. Recent results have demonstrated the importance of cholesterol for protein traffic from the trans-Golgi network to the apical cell membrane. This novel intracellular function of cholesterol could point to a connection between cell polarity and the pathogenesis of arteriosclerosis. The polarity of the endothelium also has to be taken into account when developing gene-therapeutic strategies, since therapeutic success will not only depend on the efficient expression of the desired gene product, but also on its correct cellular location or secretion into the correct extracellular compartment. These

  17. Manipulation of lipoplex concentration at the cell surface boosts transfection efficiency in hard-to-transfect cells.

    Science.gov (United States)

    Palchetti, Sara; Pozzi, Daniela; Marchini, Cristina; Amici, Augusto; Andreani, Cristina; Bartolacci, Caterina; Digiacomo, Luca; Gambini, Valentina; Cardarelli, Francesco; Di Rienzo, Carmine; Peruzzi, Giovanna; Amenitsch, Heinz; Palermo, Rocco; Screpanti, Isabella; Caracciolo, Giulio

    2017-02-01

    To date, efficiency upon non-viral DNA delivery remains low and this implies the existence of unidentified transfection barriers. Here we explore the mechanisms of action of multicomponent (MC) cationic liposome/DNA complexes (lipoplexes) by a combination of reporter technologies, dynamic light scattering (DLS), synchrotron small angle X-ray scattering (SAXS), fluorescence activated cell sorting (FACS) analysis and laser scanning confocal microscopy (LSCM) in live cells. Lipofectamine - the gold standard among transfection reagents - was used as a reference. On the basis of our results, we suggest that an additional transfection barrier impairs transfection efficiency, that is: low lipoplex concentration at the cell surface. Based on the acquired knowledge we propose an optimized transfection protocol that allowed us to efficiently transfect DND41, JURKAT, MOLT3, P12-ICHIKAWA, ALL-SILL, TALL-1 human T-cell acute lymphoblastic leukemia (T-ALL) cell lines known to be difficult-to-transfect by using non-viral vectors and where LFN-based technologies fail to give satisfactory results. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. Design and Optimization of Fresnel Lens for High Concentration Photovoltaic System

    Directory of Open Access Journals (Sweden)

    Lei Jing

    2014-01-01

    Full Text Available A practical optimization design is proposed, in which the solar direct light spectrum and multijunction cell response range are taken into account in combination, particularly for the Fresnel concentrators with a high concentration and a small aspect ratio. In addition, the change of refractive index due to temperature variation in outdoor operation conditions is also considered in the design stage. The calculation results show that this novel Fresnel lens achieves an enhancement of energy efficiency of about 10% compared with conventional Fresnel lens for a given solar spectrum, solar cell response, and corrected sunshine hours of different ambient temperature intervals.

  19. Analysing Scenarios of Cell Population System Development

    Directory of Open Access Journals (Sweden)

    M. S. Vinogradova

    2014-01-01

    Full Text Available The article considers an isolated population system consisting of two types of human stem cells, namely normal cells and cells with chromosomal abnormalities (abnormal ones. The system develops in the laboratory (in vitro. The article analyses possible scenarios of the population system development, which are implemented for different values of its parameters. An investigated model of the cell population system takes into account the limited resources. It is represented as a system of two nonlinear differential equations with continuous right-hand part. The model is considered with non-negative values of the variables; the domain is divided into four sets. The model feature is that in each set the right part of the system of differential equations has a different form.The article analyses a quality of the rest points of the system in each of four sets. The analytical conditions for determination of the number of rest points and the quality of rest points, with, at least, one zero coordinate, are obtained.It is shown that the population system under study cannot have more than two points of rest, both coordinates of which are positive (non-zero. It is difficult to determine quality of such rest points depending on the model parameters due to the complexity of the expressions, which define the systems of the first approximation, recorded in a neighborhood of these points of rest. Numerical research results of the stability of these points of rest are obtained, and phase portraits with the specified specific values of the system parameters are demonstrated. The main scenarios for the cell population development are adduced. Analysis of mathematical model shows that a cell population system may remain the system consisting of populations of normal and abnormal cells; it can degenerate into a population of abnormal cells or perish. The scenario, in which there is only the population of normal cells, is not implemented. The numerical simulation

  20. Microbial Heat Recovery Cell (MHRC) System Concept

    Energy Technology Data Exchange (ETDEWEB)

    None

    2017-09-01

    This factsheet describes a project that aimed to develop a microbial heat recovery cell (MHRC) system that combines a microbial reverse electrodialysis technology with waste heat recovery to convert industrial effluents into electricity and hydrogen.

  1. Measurement of radon decay product concentrations in South Australian cave systems

    Energy Technology Data Exchange (ETDEWEB)

    Johnston, Andrew [South Australian Health Commission, Adelaide, SA (Australia)

    1994-12-31

    Measurements of radon decay product concentrations have been conducted for periods of up to 14 days in three South Australian cave systems using a continuous monitor. The dependence of radon decay product concentrations on geology, cave use and surface atmospheric conditions is examined. The estimation of doses to workers in these caves is also discussed. 3 refs., 4 figs.

  2. Influence of zirconium ion concentration in model extraction systems TBP - diluents - Zr+4 - nitric acid

    International Nuclear Information System (INIS)

    Rogoz, F.; Tlalka, M.

    1987-07-01

    In systems containing TBP, MBP, DBP and 1-butanol stable emulsions and precipitates are formed which separation is difficult in certain domain of concentration in zirconium ions. MPB and DBP increase stability of primary emulsion in kerosen and carbon tetrachloride but for different concentrations of nitric acid. Addition of 1-butanol decreases slightly the stability of primary emulsion [fr

  3. Particle dynamics and particle-cell interaction in microfluidic systems

    Science.gov (United States)

    Stamm, Matthew T.

    Particle-laden flow in a microchannel resulting in aggregation of microparticles was investigated to determine the dependence of the cluster growth rate on the following parameters: suspension void fraction, shear strain rate, and channel-height to particle-diameter ratio. The growth rate of an average cluster was found to increase linearly with suspension void fraction, and to obey a power-law relationships with shear strain rate as S 0.9 and channel-height to particle-diameter ratio as (h/d )--3.5. Ceramic liposomal nanoparticles and silica microparticles were functionalized with antibodies that act as targeting ligands. The bio-functionality and physical integrity of the cerasomes were characterized. Surface functionalization allows cerasomes to deliver drugs with selectivity and specificity that is not possible using standard liposomes. The functionalized particle-target cell binding process was characterized using BT-20 breast cancer cells. Two microfluidic systems were used; one with both species in suspension, the other with cells immobilized inside a microchannel and particle suspension as the mobile phase. Effects of incubation time, particle concentration, and shear strain rate on particle-cell binding were investigated. With both species in suspension, the particle-cell binding process was found to be reasonably well-described by a first-order model. Particle desorption and cellular loss of binding affinity in time were found to be negligible; cell-particle-cell interaction was identified as the limiting mechanism in particle-cell binding. Findings suggest that separation of a bound particle from a cell may be detrimental to cellular binding affinity. Cell-particle-cell interactions were prevented by immobilizing cells inside a microchannel. The initial stage of particle-cell binding was investigated and was again found to be reasonably well-described by a first-order model. For both systems, the time constant was found to be inversely proportional to

  4. Small molecule ice recrystallization inhibitors enable freezing of human red blood cells with reduced glycerol concentrations.

    Science.gov (United States)

    Capicciotti, Chantelle J; Kurach, Jayme D R; Turner, Tracey R; Mancini, Ross S; Acker, Jason P; Ben, Robert N

    2015-04-08

    In North America, red blood cells (RBCs) are cryopreserved in a clinical setting using high glycerol concentrations (40% w/v) with slow cooling rates (~1°C/min) prior to storage at -80°C, while European protocols use reduced glycerol concentrations with rapid freezing rates. After thawing and prior to transfusion, glycerol must be removed to avoid intravascular hemolysis. This is a time consuming process requiring specialized equipment. Small molecule ice recrystallization inhibitors (IRIs) such as β-PMP-Glc and β-pBrPh-Glc have the ability to prevent ice recrystallization, a process that contributes to cellular injury and decreased cell viability after cryopreservation. Herein, we report that addition of 110 mM β-PMP-Glc or 30 mM β-pBrPh-Glc to a 15% glycerol solution increases post-thaw RBC integrity by 30-50% using slow cooling rates and emphasize the potential of small molecule IRIs for the preservation of cells.

  5. Improving optical performance of concentrator cells by means of a deposited nanopattern layer

    Energy Technology Data Exchange (ETDEWEB)

    García-Linares, Pablo, E-mail: pablo.garcia-linares@cea.fr; Besson, Pierre; Weick, Clément; Baudrit, Mathieu [CEA-LITEN, Laboratoire de Photovoltaïque à Concentration, INES, Le Bourget du Lac (France); Dominguez, César [CEA-LITEN, Laboratoire de Photovoltaïque à Concentration, INES, Le Bourget du Lac (France); Instituto de Energía Solar - Universidad Politécnica de Madrid, Madrid (Spain); Dellea, Olivier [CEA-LITEN, Laboratoire de Surfaces Nanostructurées, Grenoble (France); Kämpfe, Thomas; Jourlin, Yves [Laboratoire Hubert Curien UMR CNRS, Université de Lyon, St. Etienne (France)

    2015-09-28

    Multijunction solar cells (MJSC) use anti-reflective coatings (ARC) to minimize Fresnel reflection losses for a family of light incidence angles. These coatings adapt the refractive index of the cell to that of the surrounding medium. Patterns with sizes in the range of the light wavelength can be used to further reduce reflections through diffraction. Transparent nanopatterns with a gradual profile, called moth-eye nanostructures, can adapt the refractive index of the optical interfaces (often with n∼1.5) used to encapsulate concentrator solar cells to that of the air (n{sub air}∼1). Here we show the effect of a nanometric moth-eye ARC with a round motif deposited on commercial MJSC that achieves short-circuit current (I{sub SC}) gains greater than 2% at normal incidence and even higher in the case of tilted illumination. In this work, MJSC with different moth-eye ARC are characterized under quantum efficiency (QE) as well as under concentrated illumination I-V in order to assess their potential. Simulations based on coupled wave analysis (RCWA) are used to fit the experimental results with successful results.

  6. KOH concentration effect on the cycle life of nickel-hydrogen cells. 4: Results of failure analyse

    Science.gov (United States)

    Lim, H. S.; Verzwyvelt, S. A.

    1989-01-01

    Effects of KOH concentrations on failure modes and mechanisms of nickel-hydrogen cells were studied using long cycled boiler plate cells containing electrolytes of various KOH concentrations ranging 21 to 36 percent. Life of these cells were up to 40,000 cycles in an accelerated low earth orbit (LEO) cycle regime at 80 percent depth of discharge. An interim life test results were reported earlier in J. Power Sources, 22, 213-220, 1988. The results of final life test, end-of-life cell performance, and teardown analyses are discussed. These teardown analyses included visual observations, measurements of nickel electrode capacity in an electrolyte-flooded cell, dimensional changes of cell components, SEM studies on cell cross section, BET surface area and pore volume distribution in cycled nickel electrodes, and chemical analyses. Cycle life of a nickel-hydrogen cell was improved tremendously as KOH concentration was decreased from 36 to 31 percent and from 31 to 26 percent while effect of further concentration decrease was complicated as described in our earlier report. Failure mode of high concentration (31 to 36 percent) cells was gradual capacity decrease, while that of low concentration (21 to 26 percent) cells was mainly formation of a soft short. Long cycled (25,000 to 40,000 cycles) nickel electrodes were expanded more than 50 percent of the initial value, but no correlation was found between this expansion and measured capacity. All electrodes cycled in low concentration (21 to 26 percent) cells had higher capacity than those cycled in high concentration (31 to 36 percent) cells.

  7. Performance of a concentrated photovoltaic energy system with static linear Fresnel lenses

    NARCIS (Netherlands)

    Sonneveld, P.J.; Swinkels, G.L.A.M.; Tuijl, van B.A.J.; Janssen, H.J.J.; Campen, J.B.; Bot, G.P.A.

    2011-01-01

    A new type of greenhouse with linear Fresnel lenses in the cover performing as a concentrated photovoltaic (CPV) system is presented. The CPV system retains all direct solar radiation, while diffuse solar radiation passes through and enters into the greenhouse cultivation system. The removal of all

  8. Inhibitory effect of extracellular purine nucleotide and nucleoside concentrations on T cell proliferation

    Energy Technology Data Exchange (ETDEWEB)

    Weiler, Monica [Department of Medicine III and Transfusion Medicine, University Hospital Grosshadern, Ludwig-Maximilians-University, Munich (Germany); Schmetzer, Helga [Helmholtz Center Munich (Germany); German Research Center for Environmental Health, Munich (Germany); Braeu, Marion; Buhmann, Raymund [Helmholtz Center Munich (Germany); German Research Center for Environmental Health, Munich (Germany); Department of Medicine III and Transfusion Medicine, University Hospital Grosshadern, Ludwig-Maximilians-University, Munich (Germany)

    2016-11-15

    The release of nucleic acids and derivatives after tissue-injury may affect cellular immune-response. We studied the impact of extracellular ribo-, desoxyribonucleotides and nucleosides on T-cell immunity. Peripheral-blood-mononuclear-cells (PBMCs) or isolated CD3{sup +}T-cells obtained from 6 healthy donors were stimulated via CD3/CD28 Dynabeads or dendritic cells (DCs) in the presence or absence of pyrimidine-, purine-nucleotides and -nucleosides (range 2–200 µM). Addition of deoxy-, guanosine-triphosphate (dGTP, GTP) and guanosine resulted concentration dependent in a complete, adenosine-triphosphate (ATP) in a partial inhibition of the induced T-cell-proliferation. Deoxyadenosine-triphosphate (dATP), adenosine and the pyrimidine-ribo- and -deoxyribonucleotides displayed no inhibitory capacity. Inhibitory effects of dGTP and GTP, but not of guanosine and ATP were culture-media-dependent and could be almost abrogated by use of the serum-free lymphocyte-culture-media X-Vivo15 instead of RPMI1640 with standard-supplementation. In contrast to RPMI1640, X-Vivo15 resulted in a significant down-regulation of the cell-surface-located ectonucleotidases CD39 (Ecto-Apyrase) and CD73 (Ecto-5′-Nucleotidase), critical for the extracellular nucleotides-hydrolysis to nucleosides, explaining the loss of inhibition mediated by dGTP and GTP, but not Guanosine. In line with previous findings ATP was found to exert immunosuppressive effects on T-cell-proliferation. Purine-nucleotides, dGTP and GTP displayed a higher inhibitory capacity, but seem to be strictly dependent on the microenvironmental conditions modulating the responsiveness of the respective T-lymphocytes. Further evaluation of experimental and respective clinical settings should anticipate these findings.

  9. Inhibitory effect of extracellular purine nucleotide and nucleoside concentrations on T cell proliferation

    International Nuclear Information System (INIS)

    Weiler, Monica; Schmetzer, Helga; Braeu, Marion; Buhmann, Raymund

    2016-01-01

    The release of nucleic acids and derivatives after tissue-injury may affect cellular immune-response. We studied the impact of extracellular ribo-, desoxyribonucleotides and nucleosides on T-cell immunity. Peripheral-blood-mononuclear-cells (PBMCs) or isolated CD3 + T-cells obtained from 6 healthy donors were stimulated via CD3/CD28 Dynabeads or dendritic cells (DCs) in the presence or absence of pyrimidine-, purine-nucleotides and -nucleosides (range 2–200 µM). Addition of deoxy-, guanosine-triphosphate (dGTP, GTP) and guanosine resulted concentration dependent in a complete, adenosine-triphosphate (ATP) in a partial inhibition of the induced T-cell-proliferation. Deoxyadenosine-triphosphate (dATP), adenosine and the pyrimidine-ribo- and -deoxyribonucleotides displayed no inhibitory capacity. Inhibitory effects of dGTP and GTP, but not of guanosine and ATP were culture-media-dependent and could be almost abrogated by use of the serum-free lymphocyte-culture-media X-Vivo15 instead of RPMI1640 with standard-supplementation. In contrast to RPMI1640, X-Vivo15 resulted in a significant down-regulation of the cell-surface-located ectonucleotidases CD39 (Ecto-Apyrase) and CD73 (Ecto-5′-Nucleotidase), critical for the extracellular nucleotides-hydrolysis to nucleosides, explaining the loss of inhibition mediated by dGTP and GTP, but not Guanosine. In line with previous findings ATP was found to exert immunosuppressive effects on T-cell-proliferation. Purine-nucleotides, dGTP and GTP displayed a higher inhibitory capacity, but seem to be strictly dependent on the microenvironmental conditions modulating the responsiveness of the respective T-lymphocytes. Further evaluation of experimental and respective clinical settings should anticipate these findings.

  10. High concentration of Daunorubicin and Daunorubicinol in human malignant astrocytomas after systemic administration of liposomal Daunorubicin

    NARCIS (Netherlands)

    Albrecht, K. W.; de Witt Hamer, P. C.; Leenstra, S.; Bakker, P. J.; Beijnen, J. H.; Troost, D.; Kaaijk, P.; Bosch, A. D.

    2001-01-01

    The value of chemotherapy in patients with malignant astrocytoma remains controversial. In our laboratories in vitro experiments with organotypic spheroid cultures showed superior effectiveness of anthracyclines. Systemic administration did not provide in therapeutic concentrations so far. Because

  11. Lithography-free nanofluidic concentrator based on droplets-on-demand system

    Science.gov (United States)

    Yu, Miao; Zhou, Hongbo; Yao, Shuhuai

    2013-11-01

    Biomarkers are usually low-abundance proteins in biofluids and below detection limit of conventional biosensors. Nanofluidic concentration devices allow efficient biomolecules trapping by utilizing ion concentration polarization near nanochannels. However, once the electric field is turned off, the electrokinetic concentration plug cannot maintain its concentration status and starts to diffuse. In order to maintain the high concentration and extract the concentrated sample for further analysis, a good approach is to encapsulate these plugs into water-in-oil droplets. Here we developed a nanofluidic concentrator based on droplet-on-demand generator to encapsulate concentrated sample in nL droplets. The lithography-free nanochannels were patterned by thermal cracking on the surface of PS Petri-dish. The resulting nanochannel arrays were 30 nm in depth. In combination with microchannels on PDMS, the micro-nano hybrid chip was developed. We used FITC solution to demonstrate that the chip significantly increased the sample concentration for more than 100 folds within 5 minutes. By tuning the pulsed pressure imposed by the solenoid valve connected to the concentration channel, the system can generate a desired volume of droplet with a target sample concentration at a prescribed time. This work was supported by the Research Grants Council of Hong Kong under General Research Fund (Grant No. 621110).

  12. Optimization of catholyte concentration and anolyte pHs in two chamber microbial electrolysis cells

    KAUST Repository

    Nam, Joo-Youn

    2012-12-01

    The hydrogen production rate in a microbial electrolysis cell (MEC) using a non-buffered saline catholyte (NaCl) can be optimized through proper control of the initial anolyte pH and catholyte NaCl concentration. The highest hydrogen yield of 3.3 ± 0.4 mol H2/mole acetate and gas production rate of 2.2 ± 0.2 m3 H2/m3/d were achieved here with an initial anolyte pH = 9 and catholyte NaCl concentration of 98 mM. Further increases in the salt concentration substantially reduced the anolyte pH to as low as 4.6, resulting in reduced MEC performance due to pH inhibition of exoelectrogens. Cathodic hydrogen recovery was high (rcat > 90%) as hydrogen consumption by hydrogenotrophic methanogens was prevented by separating the anode and cathode chambers using a membrane. These results show that the MEC can be optimized for hydrogen production through proper choices in the concentration of a non-buffered saline catholyte and initial anolyte pH in two chamber MECs. Copyright © 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

  13. Direct methanol feed fuel cell and system

    Science.gov (United States)

    Surampudi, Subbarao (Inventor); Frank, Harvey A. (Inventor); Narayanan, Sekharipuram R. (Inventor); Chun, William (Inventor); Jeffries-Nakamura, Barbara (Inventor); Kindler, Andrew (Inventor); Halpert, Gerald (Inventor)

    2009-01-01

    Improvements to non acid methanol fuel cells include new formulations for materials. The platinum and ruthenium are more exactly mixed together. Different materials are substituted for these materials. The backing material for the fuel cell electrode is specially treated to improve its characteristics. A special sputtered electrode is formed which is extremely porous. The fuel cell system also comprises a fuel supplying part including a meter which meters an amount of fuel which is used by the fuel cell, and controls the supply of fuel based on said metering.

  14. Real-time direct cell concentration and viability determination using a fully automated microfluidic platform for standalone process monitoring

    DEFF Research Database (Denmark)

    Rodrigues de Sousa Nunes, Pedro André; Kjaerulff, S.; Dufva, Martin

    2015-01-01

    The industrial production of cells has a large unmet need for greater process monitoring, in addition to the standard temperature, pH and oxygen concentration determination. Monitoring the cell health by a vast range of fluorescence cell-based assays can greatly improve the feedback control...

  15. [The Influence of Different Ionic Concentration in Cell Physiological Solution on Temperature Measurement by Near Infrared].

    Science.gov (United States)

    Zheng, Yu; Chen, Xiong; Zhou, Mei; Wang, Meng-jun; Wang, Jin-hai; Li, Gang; Cui, Jun

    2015-10-01

    It is important to real-timely monitor and control the temperature of cell physiological solution in patch clamp experiments, which can eliminate the uncertainty due to temperature and improve the measurement accuracy. This paper studies the influence of different ions at different concentrations in the physiological solution on precision of a temperature model by using near infrared spectroscopy and chemometrics method. Firstly, we prepared twelve sample solutions respectively with the solutes of CaCl2, KCl and NaCl at four kinds of concentrations, and collected the spectra of different solutions at the setting temperature range 20-40 degrees C, the range of the spectra is 9 615-5 714 cm(-1). Then we divided the spectra of each solution at different temperatures into two parts (a training set and a prediction set) by three methods. Interval partial least squares method was used to select an effective wavelength range and develop calibration models between the spectra in the selected range and temperature velues. The experimental results show that RMSEP of CaCl2 solution with 0.25 g x mL(-1) is maximum, the result of the three tests are 0.386 3, 0.303 7 and 0.337 2 degrees C, RMSEP of NaCl with 0.005 g x mL(-1) solution is minimum, the result of the three tests are 0.220 8, 0.155 3 and 0.145 2 degrees C. The experimental results indicate that Ca2+ has the greatest influence on the accuracy of the temperature model of the cell physiological solution, then K+, and Na+ has the least influence. And with the ionic concentration increasing, the model accuracy decreases. Therefore; when we build the temperature model of cell physiological solution, it is necessary to change the proportion of the three kinds of main ions in cell physiological solution reasonably in order to correct the effects of different ionic concentrations in physiological solution and improve the accuracy of temperature measurements by near infrared spectroscopy.

  16. Buffer layer between a planar optical concentrator and a solar cell

    Directory of Open Access Journals (Sweden)

    Manuel E. Solano

    2015-09-01

    Full Text Available The effect of inserting a buffer layer between a periodically multilayered isotropic dielectric (PMLID material acting as a planar optical concentrator and a photovoltaic solar cell was theoretically investigated. The substitution of the photovoltaic material by a cheaper dielectric material in a large area of the structure could reduce the fabrication costs without significantly reducing the efficiency of the solar cell. Both crystalline silicon (c-Si and gallium arsenide (GaAs were considered as the photovoltaic material. We found that the buffer layer can act as an antireflection coating at the interface of the PMLID and the photovoltaic materials, and the structure increases the spectrally averaged electron-hole pair density by 36% for c-Si and 38% for GaAs compared to the structure without buffer layer. Numerical evidence indicates that the optimal structure is robust with respect to small changes in the grating profile.

  17. Buffer layer between a planar optical concentrator and a solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Solano, Manuel E. [Departamento de Ingeniería Matemática and CI" 2 MA, Universidad de Concepción, Concepción, Casilla 160-C (Chile); Barber, Greg D. [Penn State Institute of Energy and the Environment, Pennsylvania State University, University Park, PA 16802 (United States); Department of Chemistry, Pennsylvania State University, University Park, PA 16802 (United States); Lakhtakia, Akhlesh [Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, PA 16802 (United States); Faryad, Muhammad [Department of Physics, Lahore University of Management Sciences, Lahore 54792 (Pakistan); Monk, Peter B. [Department of Mathematical Sciences, University of Delaware, Newark, DE 19716 (United States); Mallouk, Thomas E. [Department of Chemistry, Pennsylvania State University, University Park, PA 16802 (United States)

    2015-09-15

    The effect of inserting a buffer layer between a periodically multilayered isotropic dielectric (PMLID) material acting as a planar optical concentrator and a photovoltaic solar cell was theoretically investigated. The substitution of the photovoltaic material by a cheaper dielectric material in a large area of the structure could reduce the fabrication costs without significantly reducing the efficiency of the solar cell. Both crystalline silicon (c-Si) and gallium arsenide (GaAs) were considered as the photovoltaic material. We found that the buffer layer can act as an antireflection coating at the interface of the PMLID and the photovoltaic materials, and the structure increases the spectrally averaged electron-hole pair density by 36% for c-Si and 38% for GaAs compared to the structure without buffer layer. Numerical evidence indicates that the optimal structure is robust with respect to small changes in the grating profile.

  18. Electrochemical behavior of heavily cycled nickel electrodes in Ni/H2 cells containing electrolytes of various KOH concentrations

    Science.gov (United States)

    Lim, H. S.; Verzwyvelt, S. A.

    1989-01-01

    A study has been made of charge and discharge voltage changes with cycling of Ni/H2 cells containing electrolytes of various KOH concentrations. A study has also been made of electrochemical behavior of the nickel electrodes from the cycled Ni/H2 cells as a function of overcharge amounts. Discharge voltages depressed gradually with cycling for cells having high KOH concentrations (31 to 36 percent), but the voltages increased for those having low KOH concentrations (21 to 26 percent). To determine if there was a crystallographic change of the active material due to cycling, electrochemical behavior of nickel electrodes was studied in an electrolyte flooded cell containing either 31 or 26 percent KOH electrolyte as a function of the amount of overcharge. The changes in discharge voltage appear to indicate crystal structure changes of active material from gamma-phase to beta-phase in low KOH concentrations, and vice versa in high KOH concentration.

  19. Research and Development for Novel Thermal Energy Storage Systems (TES) for Concentrating Solar Power (CSP)

    Energy Technology Data Exchange (ETDEWEB)

    Faghri, Amir; Bergman, Theodore L; Pitchumani, Ranga

    2013-09-26

    The overall objective was to develop innovative heat transfer devices and methodologies for novel thermal energy storage systems for concentrating solar power generation involving phase change materials (PCMs). Specific objectives included embedding thermosyphons and/or heat pipes (TS/HPs) within appropriate phase change materials to significantly reduce thermal resistances within the thermal energy storage system of a large-scale concentrating solar power plant and, in turn, improve performance of the plant. Experimental, system level and detailed comprehensive modeling approaches were taken to investigate the effect of adding TS/HPs on the performance of latent heat thermal energy storage (LHTES) systems.

  20. Lithium isotope effect in the extraction systems of polyethers: effect of salt concentration

    International Nuclear Information System (INIS)

    Fang Shengqiang; Fu Lian

    1991-01-01

    Separation factors of lithium isotopes at 20 deg C were determined in the extraction systems of B15C5-CHCl 3 /LiBr-H 2 O. The initial concentration of LiBr was controlled in the extent of more than 2 mol/l. It may be established that the increase of LiBr concentration causes a remarkable increase of the separation factor. The essence of this effect due to the change in salt concentration was discussed in connection with examination of relevant phenomena in literature. It can be concluded that the relationship between α and Cm, the concentration of lithium salt, is dependent on K Q and K P express respectively, lithium isotope exchange equilibrium constants between Li-crownether complex and hydrated lithium ion for lithium concentration less than 1-2 mol/l, and between lithium salt ion pair and hydrated lithium ion for lithium concentration more than 2 mol/l in aqueous phase

  1. Micro-total analysis system for virus detection: microfluidic pre-concentration coupled to liposome-based detection.

    Science.gov (United States)

    Connelly, John T; Kondapalli, Sowmya; Skoupi, Marc; Parker, John S L; Kirby, Brian J; Baeumner, Antje J

    2012-01-01

    An integrated microfluidic biosensor is presented that combines sample pre-concentration and liposome-based signal amplification for the detection of enteric viruses present in environmental water samples. This microfluidic approach overcomes the challenges of long assay times of cell culture-based methods and the need to extensively process water samples to eliminate inhibitors for PCR-based methods. Here, viruses are detected using an immunoassay sandwich approach with the reporting antibodies tagged to liposomes. Described is the development of the integrated device for the detection of environmentally relevant viruses using feline calicivirus (FCV) as a model organism for human norovirus. In situ fabricated nanoporous membranes in glass microchannels were used in conjunction with electric fields to achieve pre-concentration of virus-liposome complexes and therefore enhance the antibody-virus binding efficiency. The concentrated complexes were eluted to a detection region downstream where captured liposomes were lysed to release fluorescent dye molecules that were then quantified using image processing. This system was compared to an optimized electrochemical liposome-based microfluidic biosensor without pre-concentration. The limit of detection of FCV of the integrated device was at 1.6 × 10(5) PFU/mL, an order of magnitude lower than that obtained using the microfluidic biosensor without pre-concentration. This significant improvement is a key step toward the goal of using this integrated device as an early screening system for viruses in environmental water samples.

  2. A comparative performance study of a photovoltaic concentrator system with discrete mirror and continuos profile for two different absorber shapes

    Energy Technology Data Exchange (ETDEWEB)

    H, Saiful; Rezau, K.M [University of Dhaka, Dhaka (Bangladesh)

    2000-07-01

    Profiles of parabolic concentrators of discrete mirror and continuos surface mirror have been designed for combined electrical thermal photovoltaic systems. In the design the changes of concentration ratio, effect of reflection, angle of incidence over the absorber have been taken into account for maximum energy collection. The performances of the system are studied for solar cells of modified grid finger for illuminations from 1-10 sun. The local concentration ratio (LCR) distribution over the absorbers for both the concentrator, the optical efficiency, thermal efficiency, electrical and thermal power output and overall efficiency have been evaluated for different values of beam radiation concentration ratio and focal distance. [Spanish] Se han disenado perfiles de concentradores parabolicos de espejo discreto y de superficie continua para sistemas fotovoltaicos combinados electricos y termicos. En el diseno los cambios de la proporcion de concentracion, del efecto de la reflexion, del angulo de incidencia sobre el observador se han tenido en cuenta para una maxima recoleccion de energia. Los rendimientos del sistema se han estudiado para celdas solares de parrilla modificada para iluminaciones solares de 1-10. Han sido evaluados para diferentes valores de la proporcion de la concentracion de la radiacion en el rayo y la distancia focal la proporcion de concentracion local (LCR) de la distribucion en los absorbedores, para el concentrador la eficiencia optica, la eficiencia termica, electrica, la produccion de energia termica y electrica y la eficiencia total.

  3. Design construction and analysis of solar ridge concentrator photovoltaic (PV) system to improve battery charging performance.

    Science.gov (United States)

    Narasimman, Kalaiselvan; Selvarasan, Iniyan

    2016-05-01

    A ridge concentrator photovoltaic system for a 10W multi-crystalline solar panel was designed with the concentration ratios of 1X and 2X. The ray tracing model of ridge concentrator photovoltaic system was carried out using Trace-Pro simulation. The optimum tilt angle for the concentrator PV system throughout the year was computed. The electrical parameters of the 3 panels were analyzed. The effect of temperature on the electrical performance of the panel was also studied. The reduction of voltage due to increasing panel temperature was managed by MPES type Charge controller. Glass reflector with reflectivity 0.95 was chosen as the ridge wall for the concentrator system. The maximum power outputs for the 1X and 2X panel reached were 9W and 10.5W with glass reflector. The percentage of power improvement for 1X and 2X concentrations were 22.3% and 45.8% respectively. The 2X concentrated panel connected battery takes lower time to charge compared with normal panel connected battery. Copyright © 2016. Published by Elsevier Inc.

  4. Effect of the ethanol concentration in the anode on the direct ethanol fuel cell performance

    Energy Technology Data Exchange (ETDEWEB)

    Belchor, Pablo Martins; Loeser, Neiva; Forte, Maria Madalena de Camargo [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil); Carpenter, Deyse [Fundacao Universidade Regional de Blumenau (FURB), Blumenau, SC (Brazil)], Email: rafarstv@hotmail.com

    2010-07-01

    Changes in the climate, sources and development of renewable energy are issues that have gain greater importance, and fuel cells have been investigated as an alternative source to produce energy through electrochemical reactions. Among the fuel cells types the Proton Exchange Membrane (PEMFC), fed with pure hydrogen at the anode and oxygen at the cathode, seen be the more promising ones as an electrolyte for portable, mobile and stationary applications due to its low emissions, low operating temperature, high power density and quick configuration. To avoid inconvenience of storage and transportation of pure hydrogen a PEMFC fed with alcohols has been developed, named Direct Alcohol Fuel Cells (DAFC). One way to increase the performance of DAFC is added water in the alcohol inserted into the anode, because the water keeps the membrane hydrated. In this work, the performance of a DAFC was evaluated by following the loss in the polarization curve and cell power by varying the ethanol/water ratio. The aim of this study was determine the optimal water/ethanol ratio to be feed in a DEFC prototype mounted in the lab. By the results it was possible to point that the best concentration of ethanol aqueous solution for the DEFC tested was around 1 mol.L-1. (author)

  5. Sunlight to hydrogen conversion: Design optimization and energy management of concentrated photovoltaic (CPV-Hydrogen) system using micro genetic algorithm

    KAUST Repository

    Burhan, Muhammad

    2016-02-14

    Owing to the intermittent solar irradiance from cloud cover in the diurnal period and unavailability at night time, the practical design of a solar system requires energy backup storage for an uninterrupted supply or for off-grid operation. However, for highly efficient CPV (concentrated photovoltaic) system, the literature is lacking for energy management and optimization algorithm and tool for standalone operation. In this paper, a system with CPV and electrolyser is presented where beam irradiance of sunlight is harnessed to convert the instantaneously generated electricity into useful Hydrogen/Oxygen gas, where they can be stored and re-used for downstream applications such as the fuel cells, etc. The multi-variable design and multi-objective optimization strategies are proposed and presented for a standalone operation of the CPV-Hydrogen system as well as their system performances, particularly electrical rating of CPV based upon the real weather data of Singapore. © 2016 Elsevier Ltd.

  6. Long bone nonunions treated with autologous concentrated bone marrow-derived cells combined with dried bone allograft.

    Science.gov (United States)

    Scaglione, M; Fabbri, L; Dell'Omo, D; Gambini, F; Guido, G

    2014-08-01

    Nowadays the treatment of long bone nonunion continues to be one of the most complex and debated topics due to the large number of failures. For several years, in the relevant literature three factors have been considered essential in the healing process: growth factors and hormones, osteoprogenitor cells (mesenchymal stem cells), and extracellular matrix. The mechanical stability of the fracture site is considered the fourth element of the "Diamond concept theory." The aim of our study was to evaluate the validity of biological adjuvants of mechanical synthesis allowing a faster healing process of nonunions. We dealt with 19 patients with long bone nonunion. All patients have been treated with concentrated mesenchymal stem cells without bone autologous transplant. We used the Extracell BMC-marrow aspirate protocol of Regen Lab. The radiographic parameters taken into account for the diagnosis of successful healing were the presence of a bridge callus, obliteration of the fracture line and bone cortical continuity. Clinically, the pain was investigated with VAS score (visual analogue scale), where zero means no pain and 10 the worst possible pain. Radiographic investigation shows complete healing in 78.9 % (15 cases) with an average time to healing of 6.5 months (minimum healing time 80 days) corresponding also in complete remission of clinical symptoms. The use of growth factors and autologous mesenchymal stem cells through the enforcement of system for tissue regeneration is a valid and innovative biotechnology technique for the treatment long bone nonunions.

  7. KOH concentration effect on the cycle life of nickel-hydrogen cells. IV - Results of failure analysis

    Science.gov (United States)

    Lim, H. S.; Verzwyvelt, S. A.

    1990-01-01

    Potassium hydroxide concentration effects on the cycle life of a Ni/H2 cell have been studied by carrying out a cycle life test on ten Ni/H2 boiler plate cells which contain electrolytes of various KOH concentrations. Failure analyses of these cells were carried out after completion of the life test, which accumulated up to 40,000 cycles at an 80-percent depth of discharge over a period of 3.7 years. These failure analyses included studies on changes of electrical characteristics of test cells, and component analyses after disassembly of the cell. The component analyses included visual inspections, dimensional changes, capacity measurements of nickel electrodes, scanning electron microscopy, surface area measurements, and chemical analyses. Results have indicated that failure mode and change in the nickel electrode varied as the concentration was varied, especially when the concentration was changed from 31 percent or higher to 26 percent or lower.

  8. KOH concentration effect on the cycle life of nickel-hydrogen cells. Part 4: Results of failure analyses

    Science.gov (United States)

    Lim, H. S.; Verzwyvelt, S. A.

    1989-01-01

    KOH concentration effects on cycle life of a Ni/H2 cell have been studied by carrying out a cycle life test of ten Ni/H2 boiler plate cells which contain electrolytes of various KOH concentrations. Failure analyses of these cells were carried out after completion of the life test which accumulated up to 40,000 cycles at an 80 percent depth of discharge over a period of 3.7 years. These failure analyses included studies on changes of electrical characteristics of test cells and component analyses after disassembly of the cell. The component analyses included visual inspections, dimensional changes, capacity measurements of nickel electrodes, scanning electron microscopy, BET surface area measurements, and chemical analyses. Results have indicated that failure mode and change in the nickel electrode varied as the concentration was varied, especially, when the concentration was changed from 31 percent or higher to 26 percent or lower.

  9. Enhancing performance of a linear dielectric based concentrating photovoltaic system using a reflective film along the edge

    International Nuclear Information System (INIS)

    Baig, Hasan; Sarmah, Nabin; Chemisana, Daniel; Rosell, Joan; Mallick, Tapas K.

    2014-01-01

    In the present study, we model and analyse the performance of a dielectric based linear concentrating photovoltaic system using ray tracing and finite element methods. The results obtained are compared with the experiments. The system under study is a linear asymmetric CPC (Compound Parabolic Concentrator) designed to operate under extreme incident angles of 0° and 55° and have a geometrical concentration ratio of 2.8×. Initial experiments showed a maximum PR (power ratio) of 2.2 compared to a non concentrating counterpart. An improvement to this has been proposed and verified by adding a reflective film along the edges of the concentrator to capture the escaping rays and minimise optical losses. The addition of the reflective film changes the incoming distribution on the solar cell. Results show an increase of 16% in the average power output while using this reflective film. On including the thermal effects it was found that the overall benefit changes to about 6% while using a reflective film. Additionally, the effects of the non-uniformity of the incoming radiation are also analysed and reported for both the cases. It is found that adding the reflective film drops the maximum power at the output by only 0.5% due to the effect of non-uniformity. - Highlights: • Optical, thermal and electrical analysis of a concentrating photovoltaic system. • Improvement in performance by use of reflective film along the edge. • Experimental validation of results. • Effects of non-uniform illumination on the performance of the CPV system. • Impact of temperature profile on the overall performance

  10. A hydrogen-ferric ion rebalance cell operating at low hydrogen concentrations for capacity restoration of iron-chromium redox flow batteries

    Science.gov (United States)

    Zeng, Y. K.; Zhao, T. S.; Zhou, X. L.; Zou, J.; Ren, Y. X.

    2017-06-01

    To eliminate the adverse impacts of hydrogen evolution on the capacity of iron-chromium redox flow batteries (ICRFBs) during the long-term operation and ensure the safe operation of the battery, a rebalance cell that reduces the excessive Fe(III) ions at the positive electrolyte by using the hydrogen evolved from the negative electrolyte is designed, fabricated and tested. The effects of the flow field, hydrogen concentration and H2/N2 mixture gas flow rate on the performance of the hydrogen-ferric ion rebalance cell have been investigated. Results show that: i) an interdigitated flow field based rebalance cell delivers higher limiting current densities than serpentine flow field based one does; ii) the hydrogen utilization can approach 100% at low hydrogen concentrations (≤5%); iii) the apparent exchange current density of hydrogen oxidation reaction in the rebalance cell is proportional to the square root of the hydrogen concentration at the hydrogen concentration from 1.3% to 50%; iv) a continuous rebalance process is demonstrated at the current density of 60 mA cm-2 and hydrogen concentration of 2.5%. Moreover, the cost analysis shows that the rebalance cell is just approximately 1% of an ICRFB system cost.

  11. Optimisation of the performance of a novel rotationally asymmetrical optical concentrator design for building integrated photovoltaic system

    International Nuclear Information System (INIS)

    Abu-Bakar, Siti Hawa; Muhammad-Sukki, Firdaus; Freier, Daria; Ramirez-Iniguez, Roberto; Mallick, Tapas Kumar; Munir, Abu Bakar; Mohd Yasin, Siti Hajar; Abubakar Mas'ud, Abdullahi; Md Yunus, Norhidayah

    2015-01-01

    Solar energy is one of the renewable energy sources that has shown promising potential in addressing the world's energy needs, particularly via the solar PV (photovoltaic) technology. However, the high cost of installation is still being considered as the main obstacle to the widespread adoption of solar PV system. The use of solar concentrators is one of the solutions that could help to produce lower cost solar PV systems. One of the existing concentrator designs is known as the RADTIRC (rotationally asymmetrical dielectric totally internally reflecting concentrator) which was developed in GCU (Glasgow Caledonian University) since 2010. This paper aims at optimising the existing RADTIRC prototype by increasing its electrical output whilst keeping the cost of the system at minimum. This is achieved by adopting a better material and a different technique to fabricate the concentrator. The optimised RADTIRC prototype was fabricated from PMMA (polymethyl-methacrylate) using injection moulding. It was found that the optimised RADTIRC-PV prototype generated an opto-electronic gain of 4.48 when compared with the bare cell under STC (standard test conditions). A comparison with the old prototype showed that the optimised RADTIRC-PV prototype increased the short circuit current by 13.57% under STC. - Highlights: • An optimisation of the performance of the RADTIRC was presented. • The optimised prototype was fabricated from PMMA using injection moulding. • The electrical and optical performances were investigated. • The optimised prototype generated an opto-electronic gain of 4.48x

  12. Sublethal concentrations of waterborne copper induce cellular stress and cell death in zebrafish embryos and larvae

    Directory of Open Access Journals (Sweden)

    Pedro P Hernandez

    2011-01-01

    Full Text Available Copper is an essential ion that forms part of the active sites of many proteins. At the same time, an excess of this metal produces free radicals that are toxic for cells and organisms. Fish have been used extensively to study the effects of metals, including copper, present in food or the environment. It has been shown that different metals induce different adaptive responses in adult fish. However, until now, scant information has been available about the responses that are induced by waterborne copper during early life stages of fish. Here, acute toxicity tests and LC50 curves have been generated for zebrafish larvae exposed to dissolved copper sulphate at different concentrations and for different treatment times. We determined that the larvae incorporate and accumulate copper present in the medium in a concentration-dependent manner, resulting in changes in gene expression. Using a transgenic fish line that expresses enhanced green fluorescent protein (EGFP under the hsp70 promoter, we monitored tissue-specific stress responses to waterborne copper by following expression of the reporter. Furthermore, TUNEL assays revealed which tissues are more susceptible to cell death after exposure to copper. Our results establish a framework for the analysis of whole-organism management of excess external copper in developing aquatic animals.

  13. Evaluation of droplet digital PCR for quantification of residual leucocytes in red blood cell concentrates.

    Science.gov (United States)

    Doescher, A; Loges, U; Petershofen, E K; Müller, T H

    2017-11-01

    Enumeration of residual white blood cells in leucoreduced blood components is essential part of quality control. Digital PCR has substantially facilitated quantitative PCR and was thus evaluated for measurements of leucocytes. Target for quantification of leucocytes by digital droplet PCR was the blood group gene RHCE. The SPEF1 gene was added as internal control for the entire assay starting with automated DNA extraction. The sensitivity of the method was determined by serial dilutions of standard samples. Quality control samples were analysed within 24 h, 7 days and 6 months after collection. Routine samples from leucodepleted red blood cell concentrates (n = 150) were evaluated in parallel by flow-cytometry (LeucoCount) and by digital PCR. Digital PCR reliably detected at least 0·4 leucocytes per assay. The mean difference between PCR and flow-cytometric results from 150 units was -0·01 (±1·0). DNA samples were stable for up to at least six months. PCR measurement of leucocytes in samples from plasma and platelet concentrates also provided valid results in a pilot study. Droplet digital PCR to enumerate leucocytes offers an alternative for quality control of leucoreduced blood products. Sensitivity, specificity and reproducibility are comparable to flow-cytometry. The option to collect samples over an extended period of time and the automatization introduce attractive features for routine quality control. © 2017 International Society of Blood Transfusion.

  14. Subinhibitory concentrations of triclosan promote Streptococcus mutans biofilm formation and adherence to oral epithelial cells.

    Directory of Open Access Journals (Sweden)

    Telma Blanca Lombardo Bedran

    Full Text Available Triclosan is a general membrane-active agent with a broad-spectrum antimicrobial activity that is commonly used in oral care products. In this study, we investigated the effect of sub-minimum inhibitory concentrations (MICs of triclosan on the capacity of the cariogenic bacterium Streptococcus mutans to form biofilm and adhere to oral epithelial cells. As quantified by crystal violet staining, biofilm formation by two reference strains of S. mutans was dose-dependently promoted, in the range of 2.2- to 6.2-fold, by 1/2 and 1/4 MIC of triclosan. Observations by scanning electron microscopy revealed the presence of a dense biofilm attached to the polystyrene surface. Growth of S. mutans in the presence of triclosan at sub-MICs also increased its capacity to adhere to a monolayer of gingival epithelial cells. The expression of several genes involved in adherence and biofilm formation in S. mutans was investigated by quantitative RT-PCR. It was found that sub-MICs of triclosan significantly increased the expression of comD, gtfC, and luxS, and to a lesser extent of gtfB and atlA genes. These findings stress the importance of maintaining effective bactericidal concentrations of therapeutic triclosan since sub-MICs may promote colonization of the oral cavity by S. mutans.

  15. Subinhibitory Concentrations of Triclosan Promote Streptococcus mutans Biofilm Formation and Adherence to Oral Epithelial Cells

    Science.gov (United States)

    Bedran, Telma Blanca Lombardo; Grignon, Louis; Spolidorio, Denise Palomari; Grenier, Daniel

    2014-01-01

    Triclosan is a general membrane-active agent with a broad-spectrum antimicrobial activity that is commonly used in oral care products. In this study, we investigated the effect of sub-minimum inhibitory concentrations (MICs) of triclosan on the capacity of the cariogenic bacterium Streptococcus mutans to form biofilm and adhere to oral epithelial cells. As quantified by crystal violet staining, biofilm formation by two reference strains of S. mutans was dose-dependently promoted, in the range of 2.2- to 6.2-fold, by 1/2 and 1/4 MIC of triclosan. Observations by scanning electron microscopy revealed the presence of a dense biofilm attached to the polystyrene surface. Growth of S. mutans in the presence of triclosan at sub-MICs also increased its capacity to adhere to a monolayer of gingival epithelial cells. The expression of several genes involved in adherence and biofilm formation in S. mutans was investigated by quantitative RT-PCR. It was found that sub-MICs of triclosan significantly increased the expression of comD, gtfC, and luxS, and to a lesser extent of gtfB and atlA genes. These findings stress the importance of maintaining effective bactericidal concentrations of therapeutic triclosan since sub-MICs may promote colonization of the oral cavity by S. mutans. PMID:24551218

  16. The influence of statins on the free intracellular calcium concentration in human umbilical vein endothelial cells

    Directory of Open Access Journals (Sweden)

    Figulla Hans R

    2004-05-01

    Full Text Available Abstract Background Statins are cholesterol-lowering drugs that are widely used to reduce the risk of cardiac infarction. Their beneficial clinical effects, however, are not restricted to their influence on cholesterol production. As several studies have shown that they have a potency of relaxing blood vessels. Methods We measured the effects of statins on the intracellular free calcium concentration ([Ca2+]i in human umbilical vein endothelial cells (HUVEC after acute application and 24-h-preincubation of statins. Results Incubation of the cells for 24 h with cerivastatin or fluvastatin significantly increased the resting [Ca2+]i. For cerivastatin this effect manifested at a concentration of 1 μM. Increase of resting [Ca2+]i in the presence of cerivastatin also occurred when the nitric oxide synthase was inhibited. Transient Ca2+ release induced by histamine was not affected. Conclusions The increase of resting [Ca2+]i after incubation with cerivastatin or fluvastatin may provide an explanation for the direct effects of statins on the endothelial-dependent vasodilatation and restoration of endothelial activity in vivo.

  17. Note: Photoluminescence measurement system for multi-junction solar cells.

    Science.gov (United States)

    Trespidi, F; Malchiodi, A; Farina, F

    2017-05-01

    We describe a photoluminescence spectroscopy system developed for studying phenomena of optical coupling in multiple-junction solar cells and processed/unprocessed wafers, under the high solar concentration levels typical of HCPV (High Concentration PhotoVoltaic) systems. The instrument operates at room temperature over two spectral ranges: 475 nm-1100 nm and 950 nm-1650 nm. Power densities exceeding 10 000 suns can be obtained on the sample. The system can host up to four compact focusable solid state laser sources, presently only three are mounted and operated at 450 nm, 520 nm, and 785 nm; they provide overlapped beams on the sample surface and can shine simultaneously the sample to study possible mutual interaction between the different junctions.

  18. Foetal Leydig cells and the neuroendocrine system.

    Science.gov (United States)

    Sklebar, Duska; Semanjski, Kristina; Kos, Marina; Sklebar, Ivan; Jezek, Davor

    2008-01-01

    It has been shown that adult human Leydig cells express a number of neuroendocrine markers, and, therefore, could be considered as a part of the neuroendocrine system in the adult. A limited number of studies have dealt with the dynamics of development of human foetal Leydig cells, whereas studies on their neuroendocrine nature are still extremely rare. Therefore, the aim of our study was to investigate the development of human foetal Leydig cells in different weeks of gestation (wg) and to check if these cells express certain markers characteristic of the diffuse neuroendocrine system (DNS). Qualitative, quantitative histological studies and immunohistochemical analyses of human foetal testicular tissue have been performed. According to our data, Leydig cells formed a dynamic population of cells within the interstitum of testes in the period between 15 and 36 wg. The total number of Leydig cells of human foetal testes changed through different stages of gestation by means of 'pulsatile' dynamics (most likely, by following the variable level of gonadotropins). At early stages of development (15-17 wg) immunohistochemical reactions for the expression of neuron specific enolase (NSE) were positive within sex cords and between them, in the interstitum. Pro-spermatogonia in the sex cords were positive, as well as elongated spindle-shaped cells of the interstitum (very likely, precursors of Leydig cells). During the later stages of development (28-36 wg), excluding the pro-spermatogonia, the interstitial Leydig cells were also positive. The results of the immunohistochemical analyses (the expression of NSE) confirmed the hypothesis that human foetal Leydig cells were of neuroendocrine nature.

  19. The concentration of copper, zinc and molybdenum in serum and red blood cells of Filipinos

    International Nuclear Information System (INIS)

    Cruz, B. de la; Lansangan, L.M.; Asprer, G.A.; Paradero, R.R.; Acuna, T.T.

    1975-01-01

    Eighty-two samples of serum and red blood cells from 32 normal subjects and 50 patients with hypertension, old myocardial infarct and diabetes mellitus were analyzed by neutron activation analysis for copper, zinc and molybdenum. The mean value of copper in the normal serum (0.56 μg/g) was found to be lower than the reported mean values of 1.13 μg/g and 1.15 μg/g for foreign subjects. The mean value of copper in the normal red blood cells (0.55 μg/g) was also found to be lower than the reported values of 0.92 μg/g and 0.95 μg/g among foreigners. The mean concentration of copper in the serum of patients with hypertension and old myocardial infarct (1.02+-0.25 μg/g) and diabetes mellitus (1.06+-0.02 μg/g) were higher than the normal value of 0.56+-0.15 μg/g. The mean concentration of zinc in the serum of patients with hypertension and old myocardial infarct (0.74+-0.38 μg/g) and in diabetes mellitus (0.61+-0.33 μg/g) were lower than the normal value of 1.25+-0.58 μg/g. The level of copper in the red blood cells of patients with hypertension and old myocardial infarct (0.99+-0.62 μg/g) and diabetes mellitus (0.75+-0.39 μg/g) were found to be higher than the normal value of (0.55+-0.41) μg/g). The mean concentration of molybdenum in the red blood cells of patients with hypertension and old myocardial infarct (1.16+-0.73 μg/g) and diabetes mellitus (1.55+-0.91 μg/g) were higher than the normal level of 0.73+-0.43 μg/g. The results are discussed

  20. Subinhibitory concentrations of cell wall synthesis inhibitors promote biofilm formation of Enterococcus faecalis

    Science.gov (United States)

    Yu, Wen; Hallinen, Kelsey; Wood, Kevin

    Enterococcus faecalis are commonly associated with hospital acquired infections, because they readily form biofilms on instruments and medical devices. Biofilms are inherently more resistant to killing by antibiotics compared to planktonic bacteria, in part because of their heterogeneous spatial structure. Surprisingly, however, subminimal inhibitory concentrations (sub-MICs) of some antibiotics can actually promote biofilm formation. Unfortunately, much is still unknown about how low drug doses affect the composition and spatial structure of the biofilm. In this work, we investigate the effects of sub-MICs of ampicillin on the formation of E. faecalis biofilms. First, we quantified biofilm mass using crystal violet staining in polystyrene microtiter plates. We found that total biofilm mass is increased over a narrow range of ampicillin concentrations before ultimately declining at higher concentrations. Second, we show that sub-MICs of ampicillin can increase mass of E. faecalis biofilms while simultaneously increasing extracellular DNA/RNA and changing total number of viable cells under confocal microscopy. Further, we use RNA-seq to identify genes differentially expressed under sub-MICs of ampicillin. Finally, we show a mathematical model to explain this phenomenon. This work was funded by The Hartwell Foundation Individual Biomedical Research Award and NSF CAREER 1553208 to KBW.

  1. Glial Cells: The Other Cells of the Nervous System

    Indian Academy of Sciences (India)

    Carl Ludwig Schleich (1859-1922) was an anaesthetist and a surgeon who for the first time emphasized the role of neuroglia in brain function. In an era that was dominated by the idea that neurons alone were functional units of the nervous system and that glial cells were a mere glue holding neurons in place, Schleich ...

  2. Activation/Inhibition of mast cells by supra-optimal antigen concentrations.

    Science.gov (United States)

    Huber, Michael

    2013-01-22

    Mast cells (MCs) are tissue resident cells of hemopoietic origin and are critically involved in allergic diseases. MCs bind IgE by means of their high-affinity receptor for IgE (FcεRI). The FcεRI belongs to a family of multi-chain immune recognition receptors and is activated by cross-linking in response to multivalent antigens (Ags)/allergens. Activation of the FcεRI results in immediate release of preformed granular substances (e.g. histamine, heparin, and proteases), generation of arachidonic acid metabolites, and production of pro-inflammatory cytokines. The FcεRI shows a remarkable, bell-shaped dose-response behavior with weak induction of effector responses at both low and high (so-called supra-optimal) Ag concentrations. This is significantly different from many other receptors, which reach a plateau phase in response to high ligand concentrations. To explain this unusual dose-response behavior of the FcεRI, scientists in the past have drawn parallels to so-called precipitin curves resulting from titration of Ag against a fixed concentration of antibody (Ab) in solution (a.k.a. Heidelberger curves). Thus, for high, supra-optimal Ag concentrations one could assume that every IgE-bound FcεRI formed a monovalent complex with "its own Ag", thus resulting in marginal induction of effector functions due to absence of receptor cross-linking. However, this was never proven to be the case. More recently, careful studies of FcεRI activation and signaling events in MCs in response to supra-optimal Ag concentrations have suggested a molecular explanation for the descending part of this bell-shaped curve. It is obvious now that extensive FcεRI/IgE/Ag clusters are formed and inhibitory molecules and signalosomes are engaged in response to supra-optimal cross-linking (amongst them the Src family kinase Lyn and the inositol-5'-phosphatase SHIP1) and they actively down-regulate MC effector responses. Thus, the analysis of MC signaling triggered by supra

  3. An Advanced Model to Precisely Estimate the Cell-Free Fetal DNA Concentration in Maternal Plasma.

    Directory of Open Access Journals (Sweden)

    Xiongbin Kang

    Full Text Available With the speedy development of sequencing technologies, noninvasive prenatal testing (NIPT has been widely applied in clinical practice for testing for fetal aneuploidy. The cell-free fetal DNA (cffDNA concentration in maternal plasma is the most critical parameter for this technology because it affects the accuracy of NIPT-based sequencing for fetal trisomies 21, 18 and 13. Several approaches have been developed to calculate the cffDNA fraction of the total cell-free DNA in the maternal plasma. However, most approaches depend on specific single nucleotide polymorphism (SNP allele information or are restricted to male fetuses.In this study, we present an innovative method to accurately deduce the concentration of the cffDNA fraction using only maternal plasma DNA. SNPs were classified into four maternal-fetal genotype combinations and three boundaries were added to capture effective SNP loci in which the mother was homozygous and the fetus was heterozygous. The median value of the concentration of the fetal DNA fraction was estimated using the effective SNPs. A depth-bias correction was performed using simulated data and corresponding regression equations for adjustments when the depth of the sequencing data was below 100-fold or the cffDNA fraction is less than 10%.Using our approach, the median of the relative bias was 0.4% in 18 maternal plasma samples with a median sequencing depth of 125-fold. There was a significant association (r = 0.935 between our estimations and the estimations inferred from the Y chromosome. Furthermore, this approach could precisely estimate a cffDNA fraction as low as 3%, using only maternal plasma DNA at the targeted region with a sequencing depth of 65-fold. We also used PCR instead of parallel sequencing to calculate the cffDNA fraction. There was a significant association (r = 98.2% between our estimations and those inferred from the Y chromosome.

  4. New Polymer Electrolyte Cell Systems

    Science.gov (United States)

    Smyrl, William H.; Owens, Boone B.; Mann, Kent; Pappenfus, T.; Henderson, W.

    2004-01-01

    PAPERS PUBLISHED: 1. Pappenfus, Ted M.; Henderson, Wesley A.; Owens, Boone B.; Mann, Kent R.; Smyrl, William H. Complexes of Lithium Imide Salts with Tetraglyme and Their Polyelectrolyte Composite Materials. Journal of the Electrochemical Society (2004), 15 1 (2), A209-A2 15. 2. Pappenfus, Ted M.; Henderson, Wesley A.; Owens, Boone B.; Mann, Kent R.; Smyrl, William H. Ionic-liquidlpolymer electrolyte composite materials for electrochemical device applications. Polymeric Materials Science and Engineering (2003), 88 302. 3. Pappenfus, Ted R.; Henderson, Wesley A.; Owens, Boone B.; Mann, Kent R.; and Smyrl, William H. Ionic Conductivity of a poly(vinylpyridinium)/Silver Iodide Solid Polymer Electrolyte System. Solid State Ionics (in press 2004). 4. Pappenfus Ted M.; Mann, Kent R; Smyrl, William H. Polyelectrolyte Composite Materials with LiPFs and Tetraglyme. Electrochemical and Solid State Letters, (2004), 7(8), A254.

  5. Development of highly efficient solid oxide electrolyzer cell systems

    DEFF Research Database (Denmark)

    Duhn, Jakob Dragsbæk

    Solid oxide electrolyzer cells (SOEC) are electrochemical devices capable of converting H2O or CO2 to H2 and CO, respectively. In this thesis, the possibility of production of CO with SOECs are investigated, since it is currently of commercial interest, but could also play a major role in the fut......Solid oxide electrolyzer cells (SOEC) are electrochemical devices capable of converting H2O or CO2 to H2 and CO, respectively. In this thesis, the possibility of production of CO with SOECs are investigated, since it is currently of commercial interest, but could also play a major role...... in the future energy system. The overall objective of the thesis was to investigate the limits for the allowed CO concentration during electrolysis of CO2 in SOECs and how the limit could be increased. A high CO concentration is desired because it lowers the strain on the separation unit and amount of recycle...

  6. A concentrator system for BI-CPVT with static linear Fresnel lenses

    NARCIS (Netherlands)

    Swinkels, G.L.A.M.; Sonneveld, P.J.; Tuijl, van B.A.J.; Janssen, H.J.J.; Zwart, de H.F.

    2011-01-01

    A greenhouse with Fresnel lenses in the south facing roof and a receiver for concentrated Photovoltaic with water cooling (CPVT system) will result in electrical and thermal energy output from the solar energy excess entering a greenhouse. The PV system converts about half of the direct radiation

  7. On the concentration of the capacity for a code division multiple access system

    OpenAIRE

    Korada, Satish Babu; Macris, Nicolas

    2007-01-01

    We prove the concentration of the capacity, in the large system limit, for a code division multiple access system over an additive white Gaussian noise channel, with Gaussian signature sequences and {\\it binary input} symbols. The probabilistic tools that are used are quite powerful and could have applications in many other similar situations.

  8. A Proposed Concentration Curriculum Design for Big Data Analytics for Information Systems Students

    Science.gov (United States)

    Molluzzo, John C.; Lawler, James P.

    2015-01-01

    Big Data is becoming a critical component of the Information Systems curriculum. Educators are enhancing gradually the concentration curriculum for Big Data in schools of computer science and information systems. This paper proposes a creative curriculum design for Big Data Analytics for a program at a major metropolitan university. The design…

  9. Feasibility and parametric evaluation of hybrid concentrated photovoltaic-thermoelectric system

    DEFF Research Database (Denmark)

    Rezaniakolaei, Alireza; Rosendahl, Lasse Aistrup

    2017-01-01

    feasibility of the hybrid system over wide range of solar concentrations and different types of heat sinks. The model takes into account critical design parameters in the CPV and the TEG module. The results of this study show that for thermoelectric materials with ZT ≈ 1, the CPV/TEG system is more efficient...... than CPV-only system. The results indicate that contribution of the TEG in power generation enhances at high sun concentrations. Depending to critical design parameters of the CPV and the TEG, there are optimal values for heat transfer coefficient in the heat sink that offer minimum energy cost....

  10. Concept of a methodical process for the design of concentrating photovoltaic systems according to the context of use

    Science.gov (United States)

    González-Correa, David; Osorio-Gómez, Gilberto; Mejía-Gutiérrez, Ricardo

    2016-09-01

    Concentrating Photo Voltaic (CPV) systems maximize energy harvested from the sun with multi-junction solar cells of less area, reducing related implementation costs and reaching energy production thresholds up to 38,9 %. Nowadays, CPV systems are generally implemented in solar energy farms in a permanent location, however, these systems could be used in other dynamic contexts, such as vehicles or portable devices. In this way, mechanical and geometrical parameters related to manipulation, transportation and installation should be carefully considered at the design stage. Besides, each condition of use presents different variables affecting these parameters. In all, there is not an established architecture for these systems, opening up the possibility of radically changing their use, geometry and components. Therefore, a concept of a methodical process for designing of CPV systems is proposed in order to predict their behavior in terms of implementation and energy production. This might allow the development of robust concepts that can be adapted to different context of use as required, providing an itinerant character and thus extending the field of implementation of these systems beyond a static use. The relevant variables for the use of CPV systems are determined through experimentation considering the implementation of Fresnel lenses as light concentrators. This allows generating a structured design guide composed of different methods of measurement, selection and development. The methodical process is based on a perspective of functional modules considering needs, technical aspects and particular usage conditions of each design and it would provide appropriate guidelines in each circumstance.

  11. Advanced photovoltaic power systems using tandem GaAs/GaSb concentrator modules

    Science.gov (United States)

    Fraas, L. M.; Kuryla, M. S.; Pietila, D. A.; Sundaram, V. S.; Gruenbaum, P. E.; Avery, J. E.; Dihn, V.; Ballantyne, R.; Samuel, C.

    1992-01-01

    In 1989, Boeing announced the fabrication of a tandem gallium concentrator solar cell with an energy conversion efficiency of 30 percent. This research breakthrough has now led to panels which are significantly smaller, lighter, more radiation resistant, and potentially less expensive than the traditional silicon flat plate electric power supply. The new Boeing tandem concentrator (BTC) module uses an array of lightweight silicone Fresnel lenses mounted on the front side of a light weight aluminum honeycomb structure to focus sunlight onto small area solar cells mounted on a thin back plane. This module design is shown schematically. The tandem solar cell in this new module consists of a gallium arsenide light sensitive cell with a 24 percent energy conversion efficiency stacked on top of a gallium antimonide infrared sensitive cell with a conversion efficiency of 6 percent. This gives a total efficiency 30 percent for the cell-stack. The lens optical efficiency is typically 85 percent. Discounting for efficiency losses associated with lens packing, cell wiring, and cell operating temperature still allows for a module efficiency of 22 percent which leads to a module power density of 300 Watts/sq. m. This performance provides more than twice the power density available from a single crystal silicon flat plate module and at least four times the power density available from amorphous silicon modules. The fact that the lenses are only 0.010 ft. thick and the aluminum foil back plane is only 0.003 ft. thick leads to a very lightweight module. Although the cells are an easy to handle thickness of 0.020 ft., the fact that they are small, occupying one-twenty-fifth of the module area, means that they add little to the module weight. After summing all the module weights and given the high module power, we find that we are able to fabricate BTC modules with specific power of 100 watts/kg.

  12. Melaleuca alternifolia concentrate inhibits in vitro entry of influenza virus into host cells.

    Science.gov (United States)

    Li, Xinghua; Duan, Songwei; Chu, Cordia; Xu, Jun; Zeng, Gucheng; Lam, Alfred King-Yin; Zhou, Junmei; Yin, Yue; Fang, Danyun; Reynolds, Maxwell John; Gu, Huaiyu; Jiang, Lifang

    2013-08-09

    Influenza virus causes high morbidity among the infected population annually and occasionally the spread of pandemics. Melaleuca alternifolia Concentrate (MAC) is an essential oil derived from a native Australian tea tree. Our aim was to investigate whether MAC has any in vitro inhibitory effect on influenza virus infection and what mechanism does the MAC use to fight the virus infection. In this study, the antiviral activity of MAC was examined by its inhibition of cytopathic effects. In silico prediction was performed to evaluate the interaction between MAC and the viral haemagglutinin. We found that when the influenza virus was incubated with 0.010% MAC for one hour, no cytopathic effect on MDCK cells was found after the virus infection and no immunofluorescence signal was detected in the host cells. Electron microscopy showed that the virus treated with MAC retained its structural integrity. By computational simulations, we found that terpinen-4-ol, which is the major bioactive component of MAC, could combine with the membrane fusion site of haemagglutinin. Thus, we proved that MAC could prevent influenza virus from entering the host cells by disturbing the normal viral membrane fusion procedure.

  13. Melaleuca alternifolia Concentrate Inhibits in Vitro Entry of Influenza Virus into Host Cells

    Directory of Open Access Journals (Sweden)

    Lifang Jiang

    2013-08-01

    Full Text Available Influenza virus causes high morbidity among the infected population annually and occasionally the spread of pandemics. Melaleuca alternifolia Concentrate (MAC is an essential oil derived from a native Australian tea tree. Our aim was to investigate whether MAC has any in vitro inhibitory effect on influenza virus infection and what mechanism does the MAC use to fight the virus infection. In this study, the antiviral activity of MAC was examined by its inhibition of cytopathic effects. In silico prediction was performed to evaluate the interaction between MAC and the viral haemagglutinin. We found that when the influenza virus was incubated with 0.010% MAC for one hour, no cytopathic effect on MDCK cells was found after the virus infection and no immunofluorescence signal was detected in the host cells. Electron microscopy showed that the virus treated with MAC retained its structural integrity. By computational simulations, we found that terpinen-4-ol, which is the major bioactive component of MAC, could combine with the membrane fusion site of haemagglutinin. Thus, we proved that MAC could prevent influenza virus from entering the host cells by disturbing the normal viral membrane fusion procedure.

  14. Evaluating the Various Cropping Systems on Cd Concentrations of Different Growth Stages of Wheat

    Directory of Open Access Journals (Sweden)

    Khoshnaz Payandeh

    2017-12-01

    Full Text Available Soil contamination with heavy metals would accumulate these elements in plant tissues and decrease qualitaty and quantity of agricultural producs and thus endanger human and animal healths. Previous crop residues and rates of fertilizers applications (especially phosphorus fertilizer are the most important effective factors on accumulation of cadmium in crop tissues. Another influential factor affecting soil shrinkage is crop rotation which induces the solubility of cadmium. This research was aimed to assess the effects of conventional cropping system on cadmium concentrations in wheat at its different growth stages by using a split plot in time experiment based on completely randomized block design with three replications in the 2014-2015 growing season in Shavoor Agricultural Research Station (Khuzestan province. Main plot consisted of cropping system (rice-wheat, fallow-wheat and sub plot of growth stages at three levels (tillering, flowering and ripening. Different wheat seed cadmium concentrations due to two cropping systems were different significantly at 1% probability level. Cadmium concentration in the seeds at rice-wheat cropping system (0.31 mg.kg-1 was higher than fallow-wheat system (0.27 mg.kg-1 which is higher than World Health Organization standards. Result of analysis of variance showed that the effect of cropping systems and different growth stages of wheat on root and stem cadmium concentrations were significant at 1% probability level. Rice-wheat cropping system resulted in higher cadmium concentration in root (1.09 mg.kg-1 and stem (0.73 mg.kg-1 compared to that of the fallow-wheat cropping system. Accumulation of cadmium in stem or root at different growth stages of wheat were not significant but it was totally additive, because range of variation of cadmium concentration from planting to harvest was low.

  15. Solar concentrator with integrated tracking and light delivery system with summation

    Science.gov (United States)

    Maxey, Lonnie Curt

    2015-05-05

    A solar light distribution system includes a solar light concentrator that is affixed externally to a light transfer tube. Solar light waves are processed by the concentrator into a collimated beam of light, which is then transferred through a light receiving port and into the light transfer tube. A reflector redirects the collimated beam of light through the tube to a light distribution port. The interior surface of the light transfer tube is highly reflective so that the light transfers through the tube with minimal losses. An interchangeable luminaire is attached to the light distribution port and provides light inside of a structure. A sun tracking device rotates the concentrator and the light transfer tube to optimize the receiving of solar light by the concentrator throughout the day. The system provides interior lighting that uses only renewable energy sources, and releases no carbon dioxide emissions into the atmosphere.

  16. Solar concentrator with integrated tracking and light delivery system with collimation

    Science.gov (United States)

    Maxey, Lonnie Curt

    2015-06-09

    A solar light distribution system includes a solar light concentrator that is affixed externally to a light transfer tube. Solar light waves are processed by the concentrator into a collimated beam of light, which is then transferred through a light receiving port and into the light transfer tube. A reflector directs the collimated beam of light through the tube to a light distribution port. The interior surface of the light transfer tube is highly reflective so that the light transfers through the tube with minimal losses. An interchangeable luminaire is attached to the light distribution port and distributes light inside of a structure. A sun tracking device rotates the concentrator and the light transfer tube to optimize the receiving of solar light by the concentrator throughout the day. The system provides interior lighting, uses only renewable energy sources, and releases no carbon dioxide emissions into the atmosphere.

  17. Operation of a Thin-Film Inflatable Concentrator System Demonstrated in a Solar Thermal Vacuum Environment

    Science.gov (United States)

    Wong, Wayne A.

    2002-01-01

    Thin-film inflatable solar concentrators offer significant advantages in comparison to stateof- the-art rigid panel concentrators, including low weight, low stowage volume, and simple gas deployment. From June 10 to 22, 2001, the ElectroMagnetic Radiation Control Experiment (EMRCE) Team used simulated solar energy to demonstrate the operation of an inflatable concentrator system at NASA Glenn Research Center's Tank 6 thermal vacuum facility. The joint Government/industry test team was composed of engineers and technicians from Glenn, the Air Force Research Laboratory, SRS Technologies, and ATK Thiokol Propulsion. The research hardware consisted of the following: 1) A thin-film inflatable concentrator; 2) The hexapod pointing and focus control system; 3) Two rigidized support struts using two candidate technologies - ultraviolet-rigidized glass and radiation-cured isographite.

  18. Review of Organic Wastewater Compound Concentrations and Removal in Onsite Wastewater Treatment Systems.

    Science.gov (United States)

    Schaider, Laurel A; Rodgers, Kathryn M; Rudel, Ruthann A

    2017-07-05

    Onsite wastewater treatment systems, such as septic systems, serve 20% of U.S. households and are common in areas not served by wastewater treatment plants (WWTPs) globally. They can be sources of nutrients and pathogen pollution and have been linked to health effects in communities where they contaminate drinking water. However, few studies have evaluated their ability to remove organic wastewater compounds (OWCs) such as pharmaceuticals, hormones, and detergents. We synthesized results from 20 studies of 45 OWCs in conventional drainfield-based and alternative onsite wastewater treatment systems to characterize concentrations and removal. For comparison, we synthesized 31 studies of these same OWCs in activated sludge WWTPs. OWC concentrations and removal in drainfields varied widely and depended on wastewater sources and compound-specific removal processes, primarily sorption and biotransformation. Compared to drainfields, alternative systems had similar median and higher maximum concentrations, reflecting a wider range of system designs and redox conditions. OWC concentrations and removal in drainfields were generally similar to those in conventional WWTPs. Persistent OWCs in groundwater and surface water can indicate the overall extent of septic system impact, while the presence of well-removed OWCs, such as caffeine and acetaminophen, may indicate discharges of poorly treated wastewater from failing or outdated septic systems.

  19. An evaluation of radioxenon detection techniques for use with a fluid-based concentration system

    Energy Technology Data Exchange (ETDEWEB)

    Russ, W.R.; Stuenkel, D.O.; Valentine, J.D. [Univ. of Cincinnati, OH (United States). Nuclear and Radiological Engineering Program; Gross, K.C. [Argonne National Lab., IL (United States). Reactor Analysis Div.

    1999-06-01

    A portable monitoring system to measure the quantity of radioxenon ({sup 131m}Xe, {sup 133}Xe, {sup 133m}Xe, and {sup 135}Xe) in the atmosphere is being developed which incorporates a fluid-based concentration system with a detection system. To this end a number of radioxenon detection techniques have been evaluated to determine the best method of analyzing the output of the concentration system, which may contain significant amounts of radon in addition to concentrated xenon. Three detector configurations have been tested to measure the characteristic electron/photon coincidence radiation: plastic scintillator/NaI(Tl), gas proportional detector/NaI(Tl), and liquid scintillator/NaI(Tl). In addition to standard coincidence measurements, some additional gating criteria were also used; pulse height discrimination, pulse shape discrimination, and delayed coincidence. While the lowest relative minimum detectable activity was achieved using the liquid scintillator with delayed coincidence gating, the best performance for fieldable detection systems depends on the ratio of xenon to radon in the output of the concentration system. A high ratio favors the use of a gas proportional/NaI(Tl) detector using coincidence gating with pulse height discrimination. The use of a plastic scintillator/NaI(Tl) detector using coincidence gating with pulse shape discrimination is preferred when the ratio is low. A portable system that monitors the abundance and ratios of atmospheric radioxenon isotopes is required for use in the field to detect nuclear weapons testing.

  20. Design and Implementation of PLC-Based Automatic Sun tracking System for Parabolic Trough Solar Concentrator

    Directory of Open Access Journals (Sweden)

    Wang Jinping

    2016-01-01

    Full Text Available A sun-tracking system for parabolic trough solar concentrators (PTCs is a control system used to orient the concentrator toward the sun always, so that the maximum energy can be collected. The work presented here is a design and development of PLC based sun tracking control system for PTC. Sun tracking control system consists of a Programmable Logic Controller (PLC and a single axis hydraulic drives tracking control system. Hydraulic drives and the necessary tracking angle algorithm have been designed and developed to perform the technical tasks. A PLC unit was employed to control and monitor the mechanical movement of the PTC and to collect and store data related to the tracking angle of PTC. It is found that the tracking error of the system is less than 0.6°. Field experience shows that tracking algorithm act stable and reliable and suit for PTCs.

  1. Redox flow cell energy storage systems

    Science.gov (United States)

    Thaller, L. H.

    1979-01-01

    NASA-Redox systems are electrochemical storage devices that use two fully soluble Redox couples, anode and cathode fluids, as active electrode materials separated by a highly selective ion exchange membrane. The reactants are contained in large storage tanks and pumped through a stack of Redox flow cells where the electrochemical reactions (reduction and oxidation) take place at porous carbon felt electrodes. A string or stack of these power producing cells is connected in series in a bipolar manner. Redox energy storage systems promise to be inexpensive and possess many features that provide for flexible design, long life, high reliability and minimal operation and maintenance costs. These features include independent sizing of power and storage capacity requirements and inclusion within the cell stack of a cell that monitors the state of charge of the system as a whole, and a rebalance cell which permits continuous correction to be made for minor side reactions that would tend to result in the anode fluid and cathode fluids becoming electrochemically out of balance. These system features are described and discussed.

  2. Development of crystalline silicon based metal wrap through (MWT) solar cells for low concentrator (2-30x) applications

    OpenAIRE

    Fellmeth, T.; Fritz, S.; Menkö, M.; Mingirulli, N.; Glatthaar, M.; Clement, F.; Biro, D.; Preu, R.

    2009-01-01

    One of the main barriers on the way to mass production of concentrator silicon solar cells is the lack of industrially feasible process sequences. Therefore, a concentrator silicon based Metal Wrap Through (CMWT) solar cell completely processed at the Fraunhofer ISE PhotoVoltaic Technology Evaluation Center (PV-TEC) is introduced. This means no clean room or photolithographic steps are necessary. Under one-sun conditions, a conversion efficiency of 18.6% could be reached which is so far the h...

  3. Differential concentration-specific effects of caffeine on cell viability, oxidative stress, and cell cycle in pulmonary oxygen toxicity in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Tiwari, Kirti Kumar; Chu, Chun; Couroucli, Xanthi; Moorthy, Bhagavatula; Lingappan, Krithika, E-mail: lingappa@bcm.edu

    2014-08-08

    Highlights: • Caffeine at 0.05 mM decreases oxidative stress in hyperoxia. • Caffeine at 1 mM decreases cell viability, increases oxidative stress in hyperoxia. • Caffeine at 1 but not 0.05 mM, abrogates hyperoxia-induced G2/M arrest. - Abstract: Caffeine is used to prevent bronchopulmonary dysplasia (BPD) in premature neonates. Hyperoxia contributes to the development of BPD, inhibits cell proliferation and decreases cell survival. The mechanisms responsible for the protective effect of caffeine in pulmonary oxygen toxicity remain largely unknown. A549 and MLE 12 pulmonary epithelial cells were exposed to hyperoxia or maintained in room air, in the presence of different concentrations (0, 0.05, 0.1 and 1 mM) of caffeine. Caffeine had a differential concentration-specific effect on cell cycle progression, oxidative stress and viability, with 1 mM concentration being deleterious and 0.05 mM being protective. Reactive oxygen species (ROS) generation during hyperoxia was modulated by caffeine in a similar concentration-specific manner. Caffeine at 1 mM, but not at the 0.05 mM concentration decreased the G2 arrest in these cells. Taken together this study shows the novel funding that caffeine has a concentration-specific effect on cell cycle regulation, ROS generation, and cell survival in hyperoxic conditions.

  4. Differential concentration-specific effects of caffeine on cell viability, oxidative stress, and cell cycle in pulmonary oxygen toxicity in vitro

    International Nuclear Information System (INIS)

    Tiwari, Kirti Kumar; Chu, Chun; Couroucli, Xanthi; Moorthy, Bhagavatula; Lingappan, Krithika

    2014-01-01

    Highlights: • Caffeine at 0.05 mM decreases oxidative stress in hyperoxia. • Caffeine at 1 mM decreases cell viability, increases oxidative stress in hyperoxia. • Caffeine at 1 but not 0.05 mM, abrogates hyperoxia-induced G2/M arrest. - Abstract: Caffeine is used to prevent bronchopulmonary dysplasia (BPD) in premature neonates. Hyperoxia contributes to the development of BPD, inhibits cell proliferation and decreases cell survival. The mechanisms responsible for the protective effect of caffeine in pulmonary oxygen toxicity remain largely unknown. A549 and MLE 12 pulmonary epithelial cells were exposed to hyperoxia or maintained in room air, in the presence of different concentrations (0, 0.05, 0.1 and 1 mM) of caffeine. Caffeine had a differential concentration-specific effect on cell cycle progression, oxidative stress and viability, with 1 mM concentration being deleterious and 0.05 mM being protective. Reactive oxygen species (ROS) generation during hyperoxia was modulated by caffeine in a similar concentration-specific manner. Caffeine at 1 mM, but not at the 0.05 mM concentration decreased the G2 arrest in these cells. Taken together this study shows the novel funding that caffeine has a concentration-specific effect on cell cycle regulation, ROS generation, and cell survival in hyperoxic conditions

  5. The concentration gradient flow battery as electricity storage system: Technology potential and energy dissipation

    Science.gov (United States)

    van Egmond, W. J.; Saakes, M.; Porada, S.; Meuwissen, T.; Buisman, C. J. N.; Hamelers, H. V. M.

    2016-09-01

    Unlike traditional fossil fuel plants, the wind and the sun provide power only when the renewable resource is available. To accommodate large scale use of renewable energy sources for efficient power production and utilization, energy storage systems are necessary. Here, we introduce a scalable energy storage system which operates by performing cycles during which energy generated from renewable resource is first used to produce highly concentrated brine and diluate, followed up mixing these two solutions in order to generate power. In this work, we present theoretical results of the attainable energy density as function of salt type and concentration. A linearized Nernst-Planck model is used to describe water, salt and charge transport. We validate our model with experiments over wide range of sodium chloride concentrations (0.025-3 m) and current densities (-49 to +33 A m-2). We find that depending on current density, charge and discharge steps have significantly different thermodynamic efficiency. In addition, we show that at optimal current densities, mechanisms of energy dissipation change with salt concentration. We find the highest thermodynamic efficiency at low concentrate concentrations. When using salt concentrations above 1 m, water and co-ion transport contribute to high energy dissipation due to irreversible mixing.

  6. Cooling Grapple System for FMEF hot cell

    International Nuclear Information System (INIS)

    Semmens, L.S.; Frandsen, G.B.; Tome, R.

    1983-01-01

    A Cooling Grapple System was designed and built to handle fuel assemblies within the FMEF hot cell. The variety of functions for which it is designed makes it unique from grapples presently in use. The Cooling Grapple can positively grip and transport assemblies vertically, retrieve assemblies from molten sodium where six inches of grapple tip is submerged, cool 7 kw assemblies in argon, and service an in-cell area of 372 m 2 (4000 ft 2 ). Novel and improved operating and maintenance features were incorporated in the design including a shear pin and mechanical catcher system to prevent overloading the grapple while allowing additional reaction time for crane shutdown

  7. High throughput solar cell ablation system

    Science.gov (United States)

    Harley, Gabriel; Pass, Thomas; Cousins, Peter John; Viatella, John

    2012-09-11

    A solar cell is formed using a solar cell ablation system. The ablation system includes a single laser source and several laser scanners. The laser scanners include a master laser scanner, with the rest of the laser scanners being slaved to the master laser scanner. A laser beam from the laser source is split into several laser beams, with the laser beams being scanned onto corresponding wafers using the laser scanners in accordance with one or more patterns. The laser beams may be scanned on the wafers using the same or different power levels of the laser source.

  8. Determination of the critical micelle concentration in simulations of surfactant systems.

    Science.gov (United States)

    Santos, Andrew P; Panagiotopoulos, Athanassios Z

    2016-01-28

    Alternative methods for determining the critical micelle concentration (cmc) are investigated using canonical and grand canonical Monte Carlo simulations of a lattice surfactant model. A common measure of the cmc is the "free" (unassociated) surfactant concentration in the presence of micellar aggregates. Many prior simulations of micellizing systems have observed a decrease in the free surfactant concentration with overall surfactant loading for both ionic and nonionic surfactants, contrary to theoretical expectations from mass-action models of aggregation. In the present study, we investigate a simple lattice nonionic surfactant model in implicit solvent, for which highly reproducible simulations are possible in both the canonical (NVT) and grand canonical (μVT) ensembles. We confirm the previously observed decrease of free surfactant concentration at higher overall loadings and propose an algorithm for the precise calculation of the excluded volume and effective concentration of unassociated surfactant molecules in the accessible volume of the solution. We find that the cmc can be obtained by correcting the free surfactant concentration for volume exclusion effects resulting from the presence of micellar aggregates. We also develop an improved method for determination of the cmc based on the maximum in curvature for the osmotic pressure curve determined from μVT simulations. Excellent agreement in cmc and other micellar properties between NVT and μVT simulations of different system sizes is observed. The methodological developments in this work are broadly applicable to simulations of aggregating systems using any type of surfactant model (atomistic/coarse grained) or solvent description (explicit/implicit).

  9. Modeling and performance analysis of a concentrated photovoltaic–thermoelectric hybrid power generation system

    International Nuclear Information System (INIS)

    Lamba, Ravita; Kaushik, S.C.

    2016-01-01

    Highlights: • Thermodynamic model of concentrated photovoltaic–thermoelectric system is analysed. • Thomson effect reduces the power output of PV, TE and hybrid PV–TEG system. • Effect of thermocouple number, irradiance, PV and TE current have been studied. • The optimum concentration ratio for maximum power output has been found out. • The overall efficiency and power output of hybrid PV–TEG system has been improved. - Abstract: In this study, a thermodynamic model for analysing the performance of a concentrated photovoltaic–thermoelectric generator (CPV–TEG) hybrid system including Thomson effect in conjunction with Seebeck, Joule and Fourier heat conduction effects has been developed and simulated in MATALB environment. The expressions for calculating the temperature of photovoltaic (PV) module, hot and cold sides of thermoelectric (TE) module are derived analytically as well. The effect of concentration ratio, number of thermocouples in TE module, solar irradiance, PV module current and TE module current on power output and efficiency of the PV, TEG and hybrid PV–TEG system have been studied. The optimum concentration ratio corresponding to maximum power output of the hybrid system has been found out. It has been observed that by considering Thomson effect in TEG module, the power output of the PV, TE and hybrid PV–TEG systems decreases and at C = 1 and 5, it reduces the power output of hybrid system by 0.7% and 4.78% respectively. The results of this study may provide basis for performance optimization of a practical irreversible CPV–TEG hybrid system.

  10. PARTICULATE MATTER CONCENTRATION AND EMISSION FACTOR IN THREE DIFFERENT LAYING HEN HOUSING SYSTEMS

    Directory of Open Access Journals (Sweden)

    Annamaria Costa

    2009-09-01

    Full Text Available The aim of this study was to evaluate PM10 concentration in three different laying hens houses (traditional battery cages with aerated open manure storage, aviary system and vertical tiered cages with manure belts with forced air drying and to evaluate particulate matter emission into atmosphere during one year of observation. Internal and external temperature and relative humidity, ventilation rate, PM10 concentration have been continuously monitored in order to evaluate particulate matter concentration changes during the day and the season and to define PM10 emission factors. PM10 concentration was corrected by gravimetric technique to lower measurements error. In the aviary system house, TSP and fine particulate matter (particles smaller than 2.5 micron concentration was measured. Average yearly PM10 concentration was remarkably higher in the aviary system house with 0.215 mg m-3 vs 108 mg m-3 for the ventilated belt house and vs 0.094 mg m-3 for the traditional battery cages house. In the Aviary system housing, TSP concentration was 0.444 mg m-3 and PM2.5 was 0.032 mg m-3, highlighting the existence of a severe working environment for men and animals. Recorded values for PM10 emission were 0.433 mg h-1 hen-1 for battery cages housing type, 0.081 mg h-1 hen-1 for ventilated belt cages house, values lower than those available in literature, while the aviary system housing type showed the highest PM10 emission (1.230 mg h-1 hen-1 with appreciable peaks during the morning, together with the increased animal activity and daily farmer operations, as feed administration, cleaning and droppings removal.

  11. Testicular superoxide dismutase activity, heat shock protein 70 concentration and blood plasma inhibin-alpha concentration of dogs with a Sertoli cell tumor in a unilateral cryptorchid testis.

    Science.gov (United States)

    Kawakami, Eiichi; Hirano, Taichi; Hori, Tatsuya; Tsutsui, Toshihiko

    2007-12-01

    The proportions of Sertoli cell tumor (SCT), seminoma and Leydig cell tumor in 50 dogs with unilateral testicular tumors were 52%, 36% and 12%, respectively. The rate of occurrence of SCT in the cryptorchid testis was very high (71%). The testicular superoxide dismutase (SOD) activity, testicular heat shock protein (HSP) 70 concentration and peripheral blood plasma inhibin (INH)-alpha concentration of 10 dogs with a unilateral cryptorchid testis and no testicular tumors, 10 dogs with SCT in a unilateral cryptorchid testis and 10 normal dogs, all aged 5-15 years, were measured in order to identify high risk factors for the occurrence of SCT in the canine cryptorchid testis. The mean SOD activity in cryptorchid testes and SCTs was significantly lower and higher, respectively, than in normal testes (both Pdogs was significantly lower and higher, respectively, than in normal dogs (Pdogs and high HSP 70 concentration in the SCTs may be related to the occurrence of SCT and tumor cell proliferation in canine cryptorchid testes.

  12. Effects of ammonium concentration and charge exchange on ammonium recovery from high strength wastewater using a microbial fuel cell

    NARCIS (Netherlands)

    Kuntke, P.; Geleij, M.; Bruning, H.; Zeeman, G.; Hamelers, H.V.M.; Buisman, C.J.N.

    2011-01-01

    Ammonium recovery using a 2 chamber microbial fuel cell (MFC) was investigated at high ammonium concentration. Increasing the ammonium concentration (from 0.07 g to 4 g ammonium-nitrogen/L) by addition of ammonium chloride did not affect the performance of the MFC. The obtained current densities by

  13. Glial Cells: The Other Cells of the Nervous System-Schwann Cells ...

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 7; Issue 8. Glial Cells: The Other Cells of the Nervous System - Schwann Cells – Regulators of the Periphery. Yasmin Khan Medha S Rajadhyaksha. Series Article Volume 7 Issue 8 August 2002 pp 8-15 ...

  14. Micropower chemical fuel-to-electric conversion : a "regenerative flip" hydrogen concentration cell promising near carnot efficiency.

    Energy Technology Data Exchange (ETDEWEB)

    Wally, Karl

    2006-05-01

    Although battery technology is relatively mature, power sources continue to impose serious limitations for small, portable, mobile, or remote applications. A potentially attractive alternative to batteries is chemical fuel-to-electric conversion. Chemical fuels have volumetric energy densities 4 to 10 times those of batteries. However, realizing this advantage requires efficient chemical fuel-to-electric conversion. Direct electrochemical conversion would be the ideal, but, for most fuels, is generally not within the state-of-the-science. Next best, chemical-to-thermal-to-electric conversion can be attractive if efficiencies can be kept high. This small investigative project was an exploration into the feasibility of a novel hybrid (i.e., thermal-electrochemical) micropower converter of high theoretical performance whose demonstration was thought to be within near-term reach. The system is comprised of a hydrogen concentration electrochemical cell with physically identical hydrogen electrodes as anode and cathode, with each electrode connected to physically identical hydride beds each containing the same low-enthalpy-of-formation metal hydride. In operation, electrical power is generated by a hydrogen concentration differential across the electrochemical cell. This differential is established via coordinated heating and passive cooling of the corresponding hydride source and sink. Heating is provided by the exothermic combustion (i.e., either flame combustion or catalytic combustion) of a chemical fuel. Upon hydride source depletion, the role of source and sink are reversed, heating and cooling reversed, electrodes commutatively reversed, cell operation reversed, while power delivery continues unchanged. This 'regenerative flip' of source and sink hydride beds can be cycled continuously until all available heating fuel is consumed. Electricity is efficiently generated electrochemically, but hydrogen is not consumed, rather the hydrogen is regeneratively

  15. GUM approach to uncertainty estimations for online 220Rn concentration measurements using Lucas scintillation cell

    International Nuclear Information System (INIS)

    Sathyabama, N.

    2014-01-01

    It is now widely recognized that, when all of the known or suspected components of errors have been evaluated and corrected, there still remains an uncertainty, that is, a doubt about how well the result of the measurement represents the value of the quantity being measured. Evaluation of measurement data - Guide to the expression of Uncertainty in Measurement (GUM) is a guidance document, the purpose of which is to promote full information on how uncertainty statements are arrived at and to provide a basis for the international comparison of measurement results. In this paper, uncertainty estimations following GUM guidelines have been made for the measured values of online thoron concentrations using Lucas scintillation cell to prove that the correction for disequilibrium between 220 Rn and 216 Po is significant in online 220 Rn measurements

  16. Highly Variable Plasma Concentrations of Voriconazole in Pediatric Hematopoietic Stem Cell Transplantation Patients

    Science.gov (United States)

    Wolfs, Tom; Jonker, Martine; de Waal, Marjolein; Egberts, Toine C. G.; Ververs, Tessa T.; Boelens, Jaap J.; Bierings, Marc

    2013-01-01

    Invasive fungal infections are of great concern in pediatric hematopoietic stem cell transplantation (HSCT) recipients. Voriconazole is usually the drug of first choice for treating or preventing invasive aspergillosis. Optimum trough levels (Ctroughs) are between 1 and 5 mg/liter. It is unclear whether these levels are reached with currently advised pediatric dosing schedules. Between 2007 and 2011, 11 patients voriconazole in the HSCT unit of UMC Utrecht. For children 12 years) (P = 0.034). The intrapatient variability in Ctrough ranged between 1 and 238%. Voriconazole was discontinued in six patients due to toxicity. These patients had a median Ctrough of 0.5 mg/liter at the initial dose (ranging from 0.5 to 2.6 mg/liter), and a medium maximal concentration of 4 mg/liter was reached. Inter- and intrapatient variability is a major concern in voriconazole treatment and necessitates therapeutic drug monitoring of dosing, especially in young children. PMID:23114771

  17. Increases in cellular calcium concentration stimulate pepsinogen secretion from dispersed chief cells

    International Nuclear Information System (INIS)

    Raufman, J.P.; Berger, S.; Cosowsky, L.; Straus, E.

    1986-01-01

    Intracellular calcium concentration ([Ca]i) and pepsinogen secretion from dispersed chief cells from guinea pig stomach were determined before and after stimulation with calcium ionophores. [Ca]i was measured using the fluorescent probe quin2. Basal [Ca]i was 105 +/- 4 nM. Pepsinogen secretion was measured with a new assay using 125 I-albumin substrate. This assay is 1000-fold more sensitive than the widely-used spectrophotometric assay, technically easy to perform, rapid, and relatively inexpensive. The kinetics and stoichiometry of ionophore-induced changes in [Ca]i and pepsinogen secretion were similar. These data support a role for calcium as a cellular mediator of pepsinogen secretion

  18. Concentrators using fluorescent substances

    Energy Technology Data Exchange (ETDEWEB)

    Hayashibara, M.; Tsukamoto, M. (Hitachi Seisakusho K.K., Tokyo (Japan))

    1990-01-01

    In luminescent concentrators - plates of polymethylmethacrylate (PMMA) or other transparent material with a fluorescent compound dispersed within them - incident light is trapped and concentrated by internal reflection, and shifted to a longer wavelength, as it interacts with fluorescent particles. Experience with the use of luminescent concentrators for electricity generation in conjunction with solar cells, in solar heaters, in amplifiers for light intensity, in long-wave converters and in display panels is discussed. Solar energy conversion efficiencies of 4-5% have been obtained in generating systems combining concentrators containing Fluorol 555 or Rhodamin 6G with GaAs solar cells. (author).

  19. Graphene-derived Fe/Co-N-C catalyst in direct methanol fuel cells: Effects of the methanol concentration and ionomer content on cell performance

    Science.gov (United States)

    Park, Jong Cheol; Choi, Chang Hyuck

    2017-08-01

    Non-precious metal catalysts (typically Fe(Co)-N-C catalysts) have been widely investigated for use as cost-effective cathode materials in low temperature fuel cells. Despite the high oxygen reduction activity and methanol-tolerance of graphene-based Fe(Co)-N-C catalysts in an acidic medium, their use in direct methanol fuel cells (DMFCs) has not yet been successfully implemented, and only a few studies have investigated this topic. Herein, we synthesized a nano-sized graphene-derived Fe/Co-N-C catalyst by physical ball-milling and a subsequent chemical modification of the graphene oxide. Twelve membrane-electrode-assemblies are fabricated with various cathode compositions to determine the effects of the methanol concentration, ionomer (i.e. Nafion) content, and catalyst loading on the DMFC performance. The results show that a graphene-based catalyst is capable of tolerating a highly-concentrated methanol feed up to 10.0 M. The optimized electrode composition has an ionomer content and catalyst loading of 66.7 wt% and 5.0 mg cm-2, respectively. The highest maximum power density is ca. 32 mW cm-2 with a relatively low PtRu content (2 mgPtRu cm-2). This study overcomes the drawbacks of conventional graphene-based electrodes using a nano-sized graphene-based catalyst and further shows the feasibility of their potential applications in DMFC systems.

  20. Determining the concentrations of the squamous cell carcinoma antigen using the Maglumi 2000 automatic analyzer.

    Science.gov (United States)

    Ni, X; Qi, S

    2014-02-01

    The aim of this paper was to validate the use of the chemiluminescence immunoassay (CLIA) for detecting the squamous cell carcinoma antigen (SCCa) in human serum or plasma using a Maglumi 2000 automatic analyzer. We performed a pilot study to examine both the sensitivity and specificity of the SCCa, in diagnosing squamous cell carcinomas. High levels of SCCa are helpful in diagnosing lung cancer, especially squamous cell carcinoma. The method was linear to 22.81 ng/mL SCCa, with a detection limit of 0.02 ng/mL. An entire assay can be completed in 40 mins. The coefficients of variation (CV) of the intra- and inter-assays were less than 5% and 6%, respectively. There was a good correlation between the present and manual method. The SCCa discriminated between the squamous cell carcinoma patients and healthy controls with an area under the receiver operating characteristic (ROC) curve of 0.9231. These results indicate that the SCCa assay showed good performance using a Maglumi 2000 automatic analyzer. This new and simple analytic system will promote the application of SCCa in clinical laboratories.

  1. Molecular mechanisms involved in the inhibition of tumor cells proliferation exposed to elevated concentrations of the epidermal growth factor

    International Nuclear Information System (INIS)

    Guillen, Isabel A; Berlanga, Jorge; Camacho, Hanlet

    2013-01-01

    The EGF promotes inhibition of cell proliferation in vitro and in vivo models depending on its concentration, application schema and the type of tumor cells on which it acts. Our research hypothesis was based on the fact that the EGF varies the expression of genes involved in a negative regulation of tumor cell lines proliferation carrying high levels of its receptor (EGFR). Our objectives were, to obtain information about the effect of EGF on tumor cell proliferation in vitro and in vivo models and, know the gene expression patterns of a group of genes involved in cancer signaling pathways and EGFR. The results showed that EGF at nanomolar concentrations inhibits the tumor cells proliferation bearing high levels of EGFR and, promotes the survival of treated animals, establishing a direct relationship between the inhibition of cell proliferation, high concentrations of EGF and, high amount of EGFR in the cells. The differential gene expression profile showed a variation in a group of genes which exert a powerful control over the cell cycle progression, gene transcription and apoptosis. It was concluded that the inhibition of tumor cell proliferation by the action of EGF is due to activation of molecular mechanisms controlling cell cycle progression. This work won the Annual Award of the Cuban Academy of Sciences in 2012

  2. Cigarette Smoking Is Associated with a Lower Concentration of CD105+ Bone Marrow Progenitor Cells

    Directory of Open Access Journals (Sweden)

    Shaul Beyth

    2015-01-01

    Full Text Available Cigarette smoking is associated with musculoskeletal degenerative disorders, delayed fracture healing, and nonunion. Bone marrow progenitor cells (BMPCs, known to express CD105, are important in local trophic and immunomodulatory activity and central to musculoskeletal healing/regeneration. We hypothesized that smoking is associated with lower levels of BMPC. Iliac bone marrow samples were collected from individuals aged 18–65 years during the first steps of pelvic surgery, under IRB approval with informed consent. Patients with active infectious or neoplastic disease, a history of cytotoxic or radiation therapy, primary or secondary metabolic bone disease, or bone marrow dysfunction were excluded. Separation process purity and the number of BMPCs recovered were assessed with FACS. BMPC populations in self-reported smokers and nonsmokers were compared using the two-tailed t-test. 13 smokers and 13 nonsmokers of comparable age and gender were included. The average concentration of BMPCs was 3.52 × 105/mL ± 2.45 × 105/mL for nonsmokers versus 1.31 × 105/mL ± 1.61 × 105/mL for smokers (t= 3.2, P=0.004. This suggests that cigarette smoking is linked to a significant decrease in the concentration of BMPCs, which may contribute to the reduced regenerative capacity of smokers, with implications for musculoskeletal maintenance and repair.

  3. Production of Concentrated Pickering Emulsions with Narrow Size Distributions Using Stirred Cell Membrane Emulsification.

    Science.gov (United States)

    Manga, Mohamed S; York, David W

    2017-09-12

    Stirred cell membrane emulsification (SCME) has been employed to prepare concentrated Pickering oil in water emulsions solely stabilized by fumed silica nanoparticles. The optimal conditions under which highly stable and low-polydispersity concentrated emulsions using the SCME approach are highlighted. Optimization of the oil flux rates and the paddle stirrer speeds are critical to achieving control over the droplet size and size distribution. Investigating the influence of oil volume fraction highlights the criticality of the initial particle loading in the continuous phase on the final droplet size and polydispersity. At a particle loading of 4 wt %, both the droplet size and polydispersity increase with increasing of the oil volume fraction above 50%. As more interfacial area is produced, the number of particles available in the continuous phase diminishes, and coincidently a reduction in the kinetics of particle adsorption to the interface resulting in larger polydisperse droplets occurs. Increasing the particle loading to 10 wt % leads to significant improvements in both size and polydispersity with oil volume fractions as high as 70% produced with coefficient of variation values as low as ∼30% compared to ∼75% using conventional homogenization techniques.

  4. Miniaturized Antimicrobial Susceptibility Test by Combining Concentration Gradient Generation and Rapid Cell Culturing

    Directory of Open Access Journals (Sweden)

    Samuel C. Kim

    2015-10-01

    Full Text Available Effective treatment of bacterial infection relies on timely diagnosis and proper prescription of antibiotic drugs. The antimicrobial susceptibility test (AST is one of the most crucial experimental procedures, providing the baseline information for choosing effective antibiotic agents and their dosages. Conventional methods, however, require long incubation times or significant instrumentation costs to obtain test results. We propose a lab-on-a-chip approach to perform AST in a simple, economic, and rapid manner. Our assay platform miniaturizes the standard broth microdilution method on a microfluidic device (20 × 20 mm that generates an antibiotic concentration gradient and delivers antibiotic-containing culture media to eight 30-nL chambers for cell culture. When tested with 20 μL samples of a model bacterial strain (E. coli ATCC 25922 treated with ampicillin or streptomycin, our method allows for the determination of minimum inhibitory concentrations consistent with the microdilution test in three hours, which is almost a factor of ten more rapid than the standard method.

  5. Differential concentration-specific effects of caffeine on cell viability, oxidative stress, and cell cycle in pulmonary oxygen toxicity in vitro.

    Science.gov (United States)

    Tiwari, Kirti Kumar; Chu, Chun; Couroucli, Xanthi; Moorthy, Bhagavatula; Lingappan, Krithika

    2014-08-08

    Caffeine is used to prevent bronchopulmonary dysplasia (BPD) in premature neonates. Hyperoxia contributes to the development of BPD, inhibits cell proliferation and decreases cell survival. The mechanisms responsible for the protective effect of caffeine in pulmonary oxygen toxicity remain largely unknown. A549 and MLE 12 pulmonary epithelial cells were exposed to hyperoxia or maintained in room air, in the presence of different concentrations (0, 0.05, 0.1 and 1mM) of caffeine. Caffeine had a differential concentration-specific effect on cell cycle progression, oxidative stress and viability, with 1mM concentration being deleterious and 0.05 mM being protective. Reactive oxygen species (ROS) generation during hyperoxia was modulated by caffeine in a similar concentration-specific manner. Caffeine at 1mM, but not at the 0.05 mM concentration decreased the G2 arrest in these cells. Taken together this study shows the novel funding that caffeine has a concentration-specific effect on cell cycle regulation, ROS generation, and cell survival in hyperoxic conditions. Copyright © 2014 Elsevier Inc. All rights reserved.

  6. Fuel cell system for transportation applications

    Science.gov (United States)

    Kumar, Romesh; Ahmed, Shabbir; Krumpelt, Michael; Myles, Kevin M.

    1993-01-01

    A propulsion system for a vehicle having pairs of front and rear wheels and a fuel tank. An electrically driven motor having an output shaft operatively connected to at least one of said pair of wheels is connected to a fuel cell having a positive electrode and a negative electrode separated by an electrolyte for producing dc power to operate the motor. A partial oxidation reformer is connected both to the fuel tank and to the fuel cell receives hydrogen-containing fuel from the fuel tank and water and air and for partially oxidizing and reforming the fuel with water and air in the presence of an oxidizing catalyst and a reforming catalyst to produce a hydrogen-containing gas. The hydrogen-containing gas is sent from the partial oxidation reformer to the fuel cell negative electrode while air is transported to the fuel cell positive electrode to produce dc power for operating the electric motor.

  7. Onion root tip cell system for biodosimetry?

    International Nuclear Information System (INIS)

    Paradiz, J; Druskovic, B.; Lovka, M.; Skrk, J.

    1996-01-01

    Methodology for radiation dose assessment based on chromosomal damage to plant cells has no yet been established, although root meristems have been the pioneer cytogenetic materials and profound analyses of irradiated meristematic cells of horse bean (Viciafaba L.) had been performed. Onion (Allium cepa L.) root tips frequently used for radiation cytogenetic studies, are recently considered to be one of the most promising plant test system for the detection of genotoxic environmental pollutants. We studied the possibility of using cytogenetic analyses of irradiated onion cells to determine the effective biological dose of ionizing radiation. The dose-effect relationships for chromosomal damages to onion meristematic cells were established after plants had been irradiated and subsequently grown in both laboratory and field conditions

  8. Ultra high open circuit voltage (>1 V) of poly-3-hexylthiophene based organic solar cells with concentrated light

    DEFF Research Database (Denmark)

    Tromholt, Thomas; Madsen, Morten Vesterager; Krebs, Frederik C

    2013-01-01

    One approach to increasing polymer solar cell efficiency is to blend poly-(3-hexyl-thiophene) with poorly electron accepting fullerene derivatives to obtain higher open circuit voltage (Voc). In this letter concentrated light is used to study the electrical properties of cell operation at up...

  9. Evaluating the impact of substrate and product concentration on a whole-cell biocatalyst during a Baeyer-Villiger reaction

    DEFF Research Database (Denmark)

    Shitu, J. O.; Chartrain, M.; Woodley, John

    2009-01-01

    The presence of high concentrations of substrate or product may impede the optimal functioning of a biocatalyst, more so in the case of whole cell biocatalysts where the metabolic status of the cells may be compromised. In this article we investigate these effects using as an example the Baeyer-V...

  10. Measuring cell identity in noisy biological systems

    Science.gov (United States)

    Birnbaum, Kenneth D.; Kussell, Edo

    2011-01-01

    Global gene expression measurements are increasingly obtained as a function of cell type, spatial position within a tissue and other biologically meaningful coordinates. Such data should enable quantitative analysis of the cell-type specificity of gene expression, but such analyses can often be confounded by the presence of noise. We introduce a specificity measure Spec that quantifies the information in a gene's complete expression profile regarding any given cell type, and an uncertainty measure dSpec, which measures the effect of noise on specificity. Using global gene expression data from the mouse brain, plant root and human white blood cells, we show that Spec identifies genes with variable expression levels that are nonetheless highly specific of particular cell types. When samples from different individuals are used, dSpec measures genes’ transcriptional plasticity in each cell type. Our approach is broadly applicable to mapped gene expression measurements in stem cell biology, developmental biology, cancer biology and biomarker identification. As an example of such applications, we show that Spec identifies a new class of biomarkers, which exhibit variable expression without compromising specificity. The approach provides a unifying theoretical framework for quantifying specificity in the presence of noise, which is widely applicable across diverse biological systems. PMID:21803789

  11. Interdependence of initial cell density, drug concentration and exposure time revealed by real-time impedance spectroscopic cytotoxicity assay

    DEFF Research Database (Denmark)

    Caviglia, Claudia; Zor, Kinga; Canepa, Silvia

    2015-01-01

    We investigated the combined effect of the initial cell density (12 500, 35 000, 75 000, and 100 000 cells cm−2) and concentration of the anti-cancer drug doxorubicin on HeLa cells by performing timedependent cytotoxicity assays using real-time electrochemical impedance spectroscopy. A correlation...... between the rate of cell death and the initial cell seeding density was found at 2.5 μM doxorubicin concentration, whereas this was not observed at 5 or 100 μM. By sensing the changes in the cell–substrate interaction using impedance spectroscopy under static conditions, the onset of cytotoxicity...... was observed 5 h earlier than when using a standard colorimetric end-point assay (MTS) which measures changes in the mitochondrial metabolism. Furthermore, with the MTS assay no cytotoxicity was observed after 15 h of incubation with 2.5 μM doxorubicin, whereas the impedance showed at this time point cell...

  12. Paralytic shellfish toxin concentration and cell density changes in Pyrodinium bahamense -Noctiluca scintillans feeding experiments.

    Science.gov (United States)

    Azanza, Rhodora V; Cruz, Lourdes J; Cariño, Flerida A; Blanco, Alelea G; Butardo, Vito M

    2010-05-01

    For the first time the potential of Noctiluca scintillans, a non-toxic mixotrophic dinoflagellate, in bioconverting and/or excreting saxitoxin has been illustrated, thus contributing to the limited knowledge on the aspects of toxin pathways in the food chain/web and predator-prey preferences. Noctiluca growth rate increased with higher Pyrodinium concentration but the ratio of Noctiluca to Pyrodinium should at least be 1:250 cells per mL. Noctiluca fed with Pyrodinium alone was found to decrease in number suggesting that the nutrients from this prey were insufficient. This was confirmed by the improved cell density of Noctiluca upon addition of 0.01% casitone to the Pyrodinium-fed Noctiluca. The alternative prey (Gymnodinium sanguineum) slowed down the grazing impact of Noctiluca on Pyrodinium. Noctiluca depleted Gymnodinium earlier than Pyrodinium showing preference over a prey with less saxitoxin. After the feeding experiments, total saxitoxin levels decreased to 72% in the Noctiluca-Pyrodinium setup whereas no saxitoxin was detected in the Noctiluca culture fed with Pyrodinium and G. sanguineum. It is possible that Gymnodinium can provide some nutrients needed to make Noctiluca more efficient in bioconverting saxitoxin. Copyright 2009 Elsevier Ltd. All rights reserved.

  13. Supplementation with concentrated milk protein in patients undergoing hematopoietic stem cell transplantation.

    Science.gov (United States)

    Perrone, Ana Carolina Amaral de São José; Barbosa, Thaís Rodrigues; da Silva, Fernanda Lopes; Perrone, Ítalo Tuler; de Carvalho, Antônio Fernandes; Stephani, Rodrigo; Dos Santos, Kelli Borges; Atalla, Ângelo; Hallack Neto, Abrahão Elias

    2017-05-01

    The aim of this study was to analyze the influence of dietary supplementation with whey protein concentrate (WPC) in the incidence of oral mucositis (OM) in patients undergoing hematopoietic stem cell transplantation (HSCT). Patients were supplemented with a daily intake of WPC delivering 50% of the daily protein requirements (DPR) according to the Dietary Reference Intakes and classified later based on the amount of ingested supplement until OM median onset. We evaluated 73 patients. Forty-three were part of the historical control and 30 were supplemented with WPC. The OM had a mean duration of 5.3 d (SD 4.5), ranging from the day of the infusion of stem cells until the 17th day after infusion and a median of 5 d after infusion. OM duration was influenced by the conditioning protocol (P WPC (P = 0.01). Patients who consumed the WPC in an amount ≥40% of DPR had a 35% reduction in duration of OM, and the incidence of OM grades 3 and 4 was 11 times smaller. Body mass index, serum albumin, and adverse reactions, such as diarrhea, nausea and vomiting, dysphagia, dry mouth and drooling, showed no statistically significant differences. WPC intake ≥40% of DPR helped to reduce the severity and duration of OM. The use of WPC in patients undergoing HSCT was shown to be safe, encouraging new studies in this population to assess its action mechanism. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. Compact Electro-Permeabilization System for Controlled Treatment of Biological Cells and Cell Medium Conductivity Change Measurement

    Directory of Open Access Journals (Sweden)

    Novickij Vitalij

    2014-10-01

    Full Text Available Subjection of biological cells to high intensity pulsed electric field results in the permeabilization of the cell membrane. Measurement of the electrical conductivity change allows an analysis of the dynamics of the process, determination of the permeabilization thresholds, and ion efflux influence. In this work a compact electro-permeabilization system for controlled treatment of biological cells is presented. The system is capable of delivering 5 μs - 5 ms repetitive square wave electric field pulses with amplitude up to 1 kV. Evaluation of the cell medium conductivity change is implemented in the setup, allowing indirect measurement of the ion concentration changes occurring due to the cell membrane permeabilization. The simulation model using SPICE and the experimental data of the proposed system are presented in this work. Experimental data with biological cells is also overviewed

  15. DESIGN COMPARISON OF EXPERIMENTAL STORM WATER DETENTION SYSTEMS TREATING CONCENTRATED ROAD RUNOFF

    Directory of Open Access Journals (Sweden)

    H. Nanbakhsh

    2005-07-01

    Full Text Available Urban drainage systems are vital infrastructure assets, which protect our cities from flooding and transmission of waterborne diseases. The objective of this research was to assess the treatment efficiencies of experimental stormwater detention (extended storage systems receiving concentrated runoff that had been primary treated by filtration with different aggregates. Five detention systems with different packing order arrangements of aggregates and plant roots were used in the system to test the effects of gravel, sand, ecosoil, block paving and turf on the water treatment performance. Inflow water, polluted by road runoff, was collected by manual abstraction with a 2 litter beaker from randomly selected gully pots the near by main roads. Several parameters such as BOD5, NO3, PO4, NH4, SS, TS, DO, pH, EC, NTU and temperature were examined based on standard method book. Results showed that concentrations of biochemical oxygen demand (BOD5 in contrast to suspended solids (SS were frequently reduced to below international secondary wastewater treatment standards. The BOD and SS concentrations within the outflow from the planted system compared to the unplanted gravel and sand systems were similar. However, BOD in the outflow of system 5 was lower than other systems. The denitrification process was not completed. This resulted in higher outflow than inflow nitrate-nitrogen concentrations. An analysis of variance indicated that some systems were similar in terms of most of their treatment performance variables including BOD and SS. It follows that there is no need to use additional aggregates with high adsorption capacities in the primary treatment stage from the water quality point of view.

  16. Thin concentrator photovoltaic module with micro-solar cells which are mounted by self-align method using surface tension of melted solder

    Science.gov (United States)

    Hayashi, Nobuhiko; Terauchi, Masaharu; Aya, Youichirou; Kanayama, Shutetsu; Nishitani, Hikaru; Nakagawa, Tohru; Takase, Michihiko

    2017-09-01

    We are developing a thin and lightweight CPV module using small size lens system made from poly methyl methacrylate (PMMA) with a short focal length and micro-solar cells to decrease the transporting and the installing costs of CPV systems. In order to achieve high conversion efficiency in CPV modules using micro-solar cells, the micro-solar cells need to be mounted accurately to the irradiated region of the concentrated sunlight. In this study, we have successfully developed self-align method thanks to the surface tension of the melted solder even utilizing commercially available surface-mounting technology (SMT). Solar cells were self-aligned to the specified positions of the circuit board by this self-align method with accuracy within ±10 µm. We actually fabricated CPV modules using this self-align method and demonstrated high conversion efficiency of our CPV module.

  17. Investigation of concentration overpotential distribution in a polymer electrolyte fuel cell. Paper no. IGEC-1-081

    International Nuclear Information System (INIS)

    Tajiri, K.; Yang, X.-G.; Wang, C.-Y.; Shinohara, K.

    2005-01-01

    Simultaneous measurement of current and high frequency resistance (HFR) distributions has been performed using a segmented polymer electrolyte fuel cell operated with H 2 /air. Each flow plate consisted of twelve segments along a serpentine flow field. Two types of gas diffusion layer (GDL), a treated hydrophobic carbon cloth coated with a microporous layer (MPL) on one side, and an untreated hydrophilic carbon cloth without MPL, were studied and contrasted. The total voltage loss is divided into three overpotentials: the activation, ohmic and concentration; and the concentration overpotential and its distribution are analyzed in detail. While the fuel cell using the GDL with MPL features a nearly uniform concentration overpotential profile, the one without-MPL shows an increase in concentration overpotential along the cathode flow. When the local concentration overpotential is plotted against the local oxygen concentration, the carbon cloth GDL without MPL showed a steeply increasing concentration overpotential with decreasing oxygen concentration, indicating a high sensitivity to the oxygen content. The same trend was observed for the GDL without MPL under lower relative humidity gases. It is thus found that the increase in concentration overpotential with decreasing oxygen concentration is related to the absence of MPL. (author)

  18. Impact of spectral irradiance distribution and temperature on the outdoor performance of concentrator photovoltaic system

    Science.gov (United States)

    Husna, Husyira Al; Shibata, Naoki; Sawano, Naoki; Ueno, Seiya; Ota, Yasuyuki; Minemoto, Takashi; Araki, Kenji; Nishioka, Kensuke

    2013-09-01

    Multi-junction solar cell is designed to have considerable effect towards the solar spectrum distribution so that the maximum solar radiation could be absorbed hence, enhancing the energy conversion efficiency of the cell. Due to its application in CPV system, the system's characteristics are more sensitive to environmental factor in comparison to flat-plate PV system which commonly equipped with Si-based solar cell. In this paper, the impact of environmental factors i.e. average photon energy (APE) and temperature of solar cell (Tcell) towards the performance of the tracking type CPV system were discussed. A year data period of direct spectral irradiance, cell temperature, and power output which recorded from November 2010 to October 2011 at a CPV system power generator plant located at Miyazaki, Japan was used in this study. The result showed that most frequent condition during operation was at APE = 1.87±0.005eV, Tcell = 65±2.5°C with performance ratio of 83.9%. Furthermore, an equivalent circuit simulation of a CPV subsystem in module unit was conducted in order to investigate the influence of environmental factors towards the performance of the module.

  19. Coal Integrated Gasification Fuel Cell System Study

    Energy Technology Data Exchange (ETDEWEB)

    Chellappa Balan; Debashis Dey; Sukru-Alper Eker; Max Peter; Pavel Sokolov; Greg Wotzak

    2004-01-31

    This study analyzes the performance and economics of power generation systems based on Solid Oxide Fuel Cell (SOFC) technology and fueled by gasified coal. System concepts that integrate a coal gasifier with a SOFC, a gas turbine, and a steam turbine were developed and analyzed for plant sizes in excess of 200 MW. Two alternative integration configurations were selected with projected system efficiency of over 53% on a HHV basis, or about 10 percentage points higher than that of the state-of-the-art Integrated Gasification Combined Cycle (IGCC) systems. The initial cost of both selected configurations was found to be comparable with the IGCC system costs at approximately $1700/kW. An absorption-based CO2 isolation scheme was developed, and its penalty on the system performance and cost was estimated to be less approximately 2.7% and $370/kW. Technology gaps and required engineering development efforts were identified and evaluated.

  20. Diagnostic system for measuring temperature, pressure, CO.sub.2 concentration and H.sub.2O concentration in a fluid stream

    Science.gov (United States)

    Partridge, Jr., William P.; Jatana, Gurneesh Singh; Yoo, Ji Hyung; Parks, II, James E.

    2017-12-26

    A diagnostic system for measuring temperature, pressure, CO.sub.2 concentration and H.sub.2O concentration in a fluid stream is described. The system may include one or more probes that sample the fluid stream spatially, temporally and over ranges of pressure and temperature. Laser light sources are directed down pitch optical cables, through a lens and to a mirror, where the light sources are reflected back, through the lens to catch optical cables. The light travels through the catch optical cables to detectors, which provide electrical signals to a processer. The processer utilizes the signals to calculate CO.sub.2 concentration based on the temperatures derived from H.sub.2O vapor concentration. A probe for sampling CO.sub.2 and H.sub.2O vapor concentrations is also disclosed. Various mechanical features interact together to ensure the pitch and catch optical cables are properly aligned with the lens during assembly and use.

  1. THE EFFECT OF BLOOD AND MILK SERUM ZINC CONCENTRATION ON MILK SOMATIC CELL COUNT IN DAIRY COWS

    Directory of Open Access Journals (Sweden)

    Ivana Davidov

    2016-11-01

    Full Text Available The objective of this study was to evaluate the effect of blood and milk zinc concentration on somatic cell count and occurrence of subclinical mastitis cases. The study was performed on thirty Holstein cows approximate same body weight, ages 3 to 5 years, with equally milk production. Blood samples were taken after the morning milking from the caudal vein and milk from all four quarters was taken before morning milking. All samples of blood and milk were taken to determined zinc, using inductively coupled plasma mass spectrometry. 37.67% (11/30 cows have blood serum zinc concentration below 7µmol/l, and 63.33% or 19/30 cows have blood serum zinc concentration higher then 13µmol/l. Also 30% (9/30 cows have somatic cell count lower then 400.000/ml which indicate absence of subclinical mastitis, but 70% (21/30 cows have somatic cell count higher then 400.000/ml which indicate subclinical mastitis. Results indicate that cows with level of zinc in blood serum higher then 13 µmol/l have lower somatic cell count. Cows with lower zinc blood serum concentration then 7 µmol/l have high somatic cell count and high incidence of subclinical mastitis. According to results in this research there is no significant effect of milk serum zinc concentration on somatic cell count in dairy cows.

  2. Low concentrations of metformin selectively inhibit CD133⁺ cell proliferation in pancreatic cancer and have anticancer action.

    Directory of Open Access Journals (Sweden)

    Shanmiao Gou

    Full Text Available Pancreatic cancer is the fourth leading cause of cancer related deaths in the United States. The prognosis remains dismal with little advance in treatment. Metformin is a drug widely used for the treatment of type II diabetes. Recent epidemiologic data revealed that oral administration of metformin is associated with a reduced risk of pancreatic cancer, suggesting its potential as a novel drug for this disease. Many studies have demonstrated the in vitro anticancer action of metformin, but the typically used concentrations were much higher than the in vivo plasma and tissue concentrations achieved with recommended therapeutic doses of metformin, and low concentrations of metformin had little effect on the proliferation of pancreatic cancer cells. We examined the effect of low concentrations of metformin on different subpopulations of pancreatic cancer cells and found that these selectively inhibited the proliferation of CD133⁺ but not CD24⁺CD44⁺ESA⁺ cells. We also examined the effect of low concentrations of metformin on cell invasion and in vivo tumor formation, demonstrating in vitro and in vivo anticancer action. Metformin was associated with a reduction of phospho-Erk and phospho-mTOR independent of Akt and AMPK phosphorylation. CD133⁺ pancreatic cancer cells are considered to be cancer stem cells that contribute to recurrence, metastasis and resistance to adjuvant therapies in pancreatic cancer. Our results provide a basis for combination of metformin with current therapies to improve the prognosis of this disease.

  3. Is Low Non-Lethal Concentration of Methylmercury Really Safe? A Report on Genotoxicity with Delayed Cell Proliferation

    Science.gov (United States)

    Crespo-Lopez, María Elena; Costa-Malaquias, Allan; Oliveira, Edivaldo H. C.; Miranda, Moysés S.; Arrifano, Gabriela P. F.; Souza-Monteiro, José R.; Sagica, Fernanda Espirito-Santo; Fontes-Junior, Enéas A.; Maia, Cristiane S. F.; Macchi, Barbarella M.; do Nascimento, José Luiz M.

    2016-01-01

    Human exposure to relatively low levels of methylmercury is worrying, especially in terms of its genotoxicity. It is currently unknown as to whether exposure to low levels of mercury (below established limits) is safe. Genotoxicity was already shown in lymphocytes, but studies with cells of the CNS (as the main target organ) are scarce. Moreover, disturbances in the cell cycle and cellular proliferation have previously been observed in neuronal cells, but no data are presently available for glial cells. Interestingly, cells of glial origin accumulate higher concentrations of methylmercury than those of neuronal origin. Thus, the aim of this work was to analyze the possible genotoxicity and alterations in the cell cycle and cell proliferation of a glioma cell line (C6) exposed to a low, non-lethal and non-apoptotic methylmercury concentration. Biochemical (mitochondrial activity) and morphological (integrity of the membrane) assessments confirmed the absence of cell death after exposure to 3 μM methylmercury for 24 hours. Even without promoting cell death, this treatment significantly increased genotoxicity markers (DNA fragmentation, micronuclei, nucleoplasmic bridges and nuclear buds). Changes in the cell cycle profile (increased mitotic index and cell populations in the S and G2/M phases) were observed, suggesting arrest of the cycle. This delay in the cycle was followed, 24 hours after methylmercury withdrawal, by a decrease number of viable cells, reduced cellular confluence and increased doubling time of the culture. Our work demonstrates that exposure to a low sublethal concentration of MeHg considered relatively safe according to current limits promotes genotoxicity and disturbances in the proliferation of cells of glial origin with sustained consequences after methylmercury withdrawal. This fact becomes especially important, since this cellular type accumulates more methylmercury than neurons and displays a vital role protecting the CNS, especially in

  4. Development of a 10 Hz measurement system for atmospheric aerosol concentration

    International Nuclear Information System (INIS)

    Bouarouri, Assia

    2014-01-01

    The goal is to develop an aerosol charger based on a corona discharge for atmospheric concentration measurements (10 3 -10 5 cm -3 ) within a response time of 100 ms. Two ion sources, point-to-hole and wire-to-slit have been characterized. The increase of the ion flow in the post-discharge by EHD ion confinement in both the discharge gap and the hole has been shown. At first, using an experimental survey driven in two mixing configurations, concentric and face-to-face, we have confirmed the aerosol diffusion charging law which depends on aerosol diameter and N i .t product, with N i , the ions concentration and t, the charging time. Thus, the originality of this charger relies on the very high heterogeneity of unipolar ion densities (N i 0 ≥10 9 cm -3 ) required to compensate the charging time of 50 ms. In these conditions, we have shown that aerosol diameter and the charging dynamic (which depends also on the diameter) control the aerosol trajectory. The chargers have, next, been compared in different operating conditions, mainly in terms of the maximal charging and the minimal losses. In the chosen charger (point-to-hole ion source and concentric mixing), the relations charge/mobility and losses according to diameter have been characterized. We have also shown the linearity of the charged particles current with the aerosol concentration which allows the current-concentration data inversion. The preliminary measurement system composed by the charger, the separator and the particle current measurements, satisfies the objectives of the study in terms of the concentration detection limit (10 3 cm -3 ) and the response time (100 ms). We have thus shown the feasibility of an atmospheric aerosol concentration measurement system at 10 Hz using a corona discharge charger provided that the separation power is improved. Furthermore, knowing that aerosol losses are negligible and the lower limit of the partial charging, the developed charger is adaptable with other

  5. [Design of high-efficiency double compound parabolic concentrator system in near infrared noninvasive biochemical analysis].

    Science.gov (United States)

    Gao, Jing; Lu, Qi-Peng; Peng, Zhong-Qi; Ding, Hai-Quan; Gao, Hong-Zhi

    2013-05-01

    High signal-to-noise ratio (SNR) of system is necessary to obtain accurate blood components in near infrared noninvasive biochemical analysis. In order to improve SNR of analytical system, high-efficiency double compound parabolic concentrator (DCPC) system was researched, which was aimed at increasing light utilization efficiency. Firstly, with the request of collection efficiency in near infrared noninvasive biochemical analysis, the characteristic of emergent rays through compound parabolic concentrator (CPC) was analyzed. Then the maximum focusing angle range of the first stage CPC was determined. Secondly, the light utilization efficiency of truncated type was compared with standard DCPC, thus the best structure parameters of DCPC system were optimized. Lastly, combined with optical parameters of skin tissue, calculations were operated when incident wavelength is 1 000 nm. The light utilization efficiency of DCPC system, CPC-focusing mirror system, and non-optical collecting system was calculated. The results show that the light utilization efficiency of the three optical systems is 1.46%, 0.84% and 0.26% respectively. So DCPC system enhances collecting ability for human diffuse reflection light, and helps improve SNR of noninvasive biochemical analysis system and overall analysis accuracy effectively.

  6. Ventilation systems as an effective tool for control of radon daughter concentration in mines

    International Nuclear Information System (INIS)

    Dory, A.B.

    1981-10-01

    Introduced with a brief discussion of the key role of ventilation in controlling mine atmospheres, the effects of the design of the ventilation system on the control of radon daughter concentrations are illustrated with specific reference to Alcan's Director Mine, St-Lawrence, Nfld. (This fluorspar mine was found to have high radon concentrations due to mine water bringing in dissolved radon.) After a discussion of the health physics history of the mine, the various phases of the ventilation system design and the general results are detailed. The author draws some conclusions having general application to the design of any mine with a radon or thoron daughter concentration. These include minimizing the 'age' of the air; the need for continuous ventilation in all areas; the value of remote control and monitoring; and the benefits of mine pressurization

  7. Lipid Droplet Formation in HeLa Cervical Cancer Cells Depends on Cell Density and the Concentration of Exogenous Unsaturated Fatty Acids.

    Science.gov (United States)

    Guštin, Ema; Jarc, Eva; Kump, Ana; Petan, Toni

    2017-09-01

    Cytosolic lipid droplets (LDs) store excess fatty acids (FAs) in the form of neutral lipids and prevent starvation-induced cancer cell death. Here we studied the ability of mono- and polyunsaturated FAs to affect LD formation and survival in HeLa cervical cancer cells. We found that the LD content in HeLa cells increases with cell density, but it decreases in MDA-MB-231 breast cancer cells. Exogenously-added unsaturated FAs, including oleic (OA), linoleic (LA), arachidonic (AA), eicosapentaenoic (EPA) and docosahexaenoic acid (DHA) displayed a similar ability to alter LD formation in HeLa cells. There was a dual, concentration-dependent effect on neutral lipid accumulation: low micromolar concentrations of LA, AA and DHA reduced, while all FAs induced LD formation at higher concentrations. In serum starved He-La cells, OA stimulated LD formation, but, contrary to expectations, it promoted cell death. Our results reveal a link between cell population density and LD formation in HeLa cells and show that unsaturated FAs may both suppress or stimulate LD formation. This dynamic regulation of LD content must be accounted for when studying the effects of lipids and lipid metabolism-targeting drugs on LD metabolism in HeLa cells.

  8. Stem cells and the aging hematopoietic system.

    Science.gov (United States)

    Beerman, Isabel; Maloney, William J; Weissmann, Irving L; Rossi, Derrick J

    2010-08-01

    Advancing age is accompanied by a number of clinically significant conditions arising in the hematopoietic system that include: diminution and decreased competence of the adaptive immune system, elevated incidence of certain autoimmune diseases, increased hematological malignancies, and elevated incidence of age-associated anemia. As with most tissues, the aged hematopoietic system also exhibits a reduced capacity to regenerate and return to normal homeostasis after injury or stress. Evidence suggests age-dependent functional alterations within the hematopoietic stem cell compartment significantly contribute to many of these pathophysiologies. Recent developments have shed light on how aging of the hematopoietic stem cell compartment contributes to hematopoietic decline through diverse mechanisms. Copyright 2010 Elsevier Ltd. All rights reserved.

  9. 50 kW on-site concentrating solar photovoltaic power system. Phase I: design. Final report, 1 June 1978-28 February 1979

    Energy Technology Data Exchange (ETDEWEB)

    Pittman, P F

    1979-03-30

    This contract is part of a three phase program to design, fabricate, and operate a solar photovoltaic electric power system with concentrating optics. The system will be located beside a Local Operating Headquarters of the Georgia Power Company in Atlanta, Georgia and will provide part of the power for the on-site load. Fresnel lens concentrators will be used in 2-axis tracking arrays to focus solar energy onto silicon solar cells producing a peak power output of 56 kW. The present contract covers Phase I which has as its objective the complete design of the system and necessary subsystems.

  10. Suitable Concentrations of Uric Acid Can Reduce Cell Death in Models of OGD and Cerebral Ischemia-Reperfusion Injury.

    Science.gov (United States)

    Zhang, Bin; Yang, Ning; Lin, Shao-Peng; Zhang, Feng

    2017-07-01

    Cerebral infarction (CI) is a common clinical cerebrovascular disease, and to explore the pathophysiological mechanisms and seek effective treatment means are the hotspot and difficult point in medical research nowadays. Numerous studies have confirmed that uric acid plays an important role in CI, but the mechanism has not yet been clarified. When treating HT22 and BV-2 cells with different concentrations of uric acid, uric acid below 450 μM does not have significant effect on cell viability, but uric acid more than 500 μM can significantly inhibit cell viability. After establishing models of OGD (oxygen-glucose deprivation) with HT22 and BV-2 cells, uric acid at a low concentration (50 μM) cannot improve cell viability and apoptosis, and Reactive oxygen species (ROS) levels during OGD/reoxygenation; a suitable concentration (300 μM) of uric acid can significantly improve cell viability and apoptosis, and reduce ROS production during OGD/reoxygenation; but a high concentration (1000 μM) of uric acid can further reduce cell viability and enhance ROS production. After establishing middle cerebral artery occlusion of male rats with suture method, damage and increase of ROS production in brain tissue could be seen, and after adding suitable concentration of uric acid, the degree of brain damage and ROS production was reduced. Therefore, different concentrations of uric acid should have different effect, and suitable concentrations of uric acid have neuroprotective effect, and this finding may provide guidance for study on the clinical curative effect of uric acid.

  11. Impact of medium volume and oxygen concentration in the incubator on pericellular oxygen concentration and differentiation of murine chondrogenic cell culture.

    Science.gov (United States)

    Oze, Hiroki; Hirao, Makoto; Ebina, Kosuke; Shi, Kenrin; Kawato, Yoshitaka; Kaneshiro, Shoichi; Yoshikawa, Hideki; Hashimoto, Jun

    2012-02-01

    Previous studies have demonstrated that oxygen environment is an important determinate factor of cell phenotypes and differentiation, although factors which affect pericellular oxygen concentration (POC) in murine chondrogenic cell culture remain unidentified. Oxygen concentrations in vivo were measured in rabbit musculoskeletal tissues, which were by far hypoxic compared to 20% O(2) (ranging from 2.29 ± 1.16 to 4.36 ± 0.51%). Oxygen concentrations in murine chondrogenic cell (C3H10T1/2) culture medium were monitored in different oxygen concentrations (20% or 5%) in the incubator and in different medium volumes (3,700 or 7,400 μl) within 25-cm(2) flasks. Chondrogenic differentiation was assessed by glycosaminoglycan production with quantitative evaluation of Alcian blue staining in 12-well culture dishes. Expression of chondrogenic genes, aggrecan, and type II collagen α1, was examined by quantitative real-time polymerase chain reaction. Oxygen concentrations in medium decreased accordingly with the depth from medium surface, and POC at Day 6 was 18.99 ± 0.81% in 3,700-μl medium (1,480-μm depth) and 13.26 ± 0.23% in 7,400-μl medium (2,960-μm depth) at 20% O(2) in the incubator, which was 4.96 ± 0.08% (1,480-μm depth) and 2.83 ± 0.42% (2,960-μm depth) at 5% O(2), respectively. The differences of POC compared by medium volume were statistically significant (p = 0.0003 at 20% and p = 0.001 at 5%). Glycosaminoglycan production and aggrecan gene expression were most promoted when cultured in moderately low POC, 1,000 μl (2,960-μm depth) at 20% O(2) and 500 μl (1,480-μm depth) at 5% O(2) in 12-well culture dishes. We demonstrate that medium volume and oxygen concentration in the incubator affect not only POC but also chondrogenic differentiation.

  12. Endotoxin concentration in poultry houses for laying hens kept in cages or in alternative housing systems

    OpenAIRE

    2011-01-01

    Abstract 1. Endotoxins as components of organic dust may have adverse effects on the respiratory health of workers in poultry buildings. The move towards more welfare-friendly housing systems for layers may increase worker exposure to air contaminants due to the use of litter. 2. The endotoxin concentrations in the inhalable fraction of airborne dust (below 100 ?m) from cage and alternative system henhouses (on-floor, free range and aviaries) were compared under both experiment...

  13. SHAPE EFFECT OF ANNULAR CONCENTRATOR IN ULTRASONIC SYSTEM ON AMPLIFICATION FACTOR OF VIBRATIONS AMPLITUDE

    Directory of Open Access Journals (Sweden)

    D. A. Stepanenko

    2016-01-01

    Full Text Available The paper contains a theoretical underpinning on creation of ultrasonic vibration concentrators based on annular elastic elements with non-circular (ellipse-like eccentric shape of internal contour. Shape of internal contour in polar coordinates is described by Fourier series relative to angular coordinate that consists of a constant term and first and second harmonics. An effect of geometric parameters of the concentrator on amplification factor and natural vibration frequencies has been investigated with the help of a finite element method. The paper reveals the possibility to control an amplification factor of annular concentrators while varying eccentricity of internal contour and mean value of cross-section thickness. The amplification factor satisfies a condition K < N, where N is thickness ratio of amplifier input and output sections, and it is decreasing with increase of vibration mode order. The similar condition has been satisfied for conical bar concentrator with the difference that in the case of bar concentrators an amplification is ensured due to variation of diameter and N will represent ratio of diameters. It has been proved that modification of internal contour shape makes it possible to carry out a wide-band tuning of natural frequencies of concentrator vibrations without alteration of its overall dimensions and substantial change of amplification factor, which is important for frequency matching of the concentrator and ultrasonic vibratory system. Advantages of the proposed concentrators include simplicity of design and manufacturing, small overall dimensions, possibility for natural frequency tuning by means of static load variation. The developed concentrators can find their application in ultrasonic devices and instruments for technological and medical purposes.

  14. Concentration of metals in shrimps and crabs from Thane-Bassein creek system, Maharashtra

    Digital Repository Service at National Institute of Oceanography (India)

    Krishnamurti, A.J.; Nair, V.R.

    Levels of Cu, Zn, Cd, Pb and Ni in shrimps and crabs from Thane-Bassein creek system, Maharashtra, India were evaluated for a period of one year and reported as baseline for future monitoring of this vital ecosystem. The pattern of concentration...

  15. Retrogradation of concentrated starch systems : mechanism and consequences for product properties

    NARCIS (Netherlands)

    Keetels, C.J.A.M.

    1995-01-01

    The mechanical properties of concentrated starch + water systems were studied during heating, cooling and storage. Methods used were a small-amplitude dynamic rheological test and compression between parallel plates. The mechanical properties were related to the structure of the gels.

  16. Investigation of Solar Hybrid Electric/Thermal System with Radiation Concentrator and Thermoelectric Generator

    Directory of Open Access Journals (Sweden)

    Edgar Arturo Chávez Urbiola

    2013-01-01

    Full Text Available An experimental study of a solar-concentrating system based on thermoelectric generators (TEGs was performed. The system included an electrical generating unit with 6 serially connected TEGs using a traditional semiconductor material, Bi2Te3, which was illuminated by concentrated solar radiation on one side and cooled by running water on the other side. A sun-tracking concentrator with a mosaic set of mirrors was used; its orientation towards the sun was achieved with two pairs of radiation sensors, a differential amplifier, and two servomotors. The hot side of the TEGs at midday has a temperature of around 200°C, and the cold side is approximately 50°C. The thermosiphon cooling system was designed to absorb the heat passing through the TEGs and provide optimal working conditions. The system generates 20 W of electrical energy and 200 W of thermal energy stored in water with a temperature of around 50°C. The hybrid system studied can be considered as an alternative to photovoltaic/thermal systems, especially in countries with abundant solar radiation, such as Mexico, China, and India.

  17. Metformin inhibition of mTORC1 activation, DNA synthesis and proliferation in pancreatic cancer cells: Dependence on glucose concentration and role of AMPK

    Energy Technology Data Exchange (ETDEWEB)

    Sinnett-Smith, James; Kisfalvi, Krisztina; Kui, Robert [Division of Digestive Diseases, Department of Medicine, CURE: Digestive Diseases Research Center, David Geffen School of Medicine and Molecular Biology Institute, University of California at Los Angeles, CA (United States); Rozengurt, Enrique, E-mail: erozengurt@mednet.ucla.edu [Division of Digestive Diseases, Department of Medicine, CURE: Digestive Diseases Research Center, David Geffen School of Medicine and Molecular Biology Institute, University of California at Los Angeles, CA (United States)

    2013-01-04

    Highlights: Black-Right-Pointing-Pointer Metformin inhibits cancer cell growth but the mechanism(s) are not understood. Black-Right-Pointing-Pointer We show that the potency of metformin is sharply dependent on glucose in the medium. Black-Right-Pointing-Pointer AMPK activation was enhanced in cancer cells incubated in physiological glucose. Black-Right-Pointing-Pointer Reciprocally, metformin potently inhibited mTORC1, DNA synthesis and proliferation. Black-Right-Pointing-Pointer Metformin, at low concentrations, inhibited DNA synthesis through AMPK. -- Abstract: Metformin, a widely used anti-diabetic drug, is emerging as a potential anticancer agent but the mechanisms involved remain incompletely understood. Here, we demonstrate that the potency of metformin induced AMPK activation, as shown by the phosphorylation of its substrates acetyl-CoA carboxylase (ACC) at Ser{sup 79} and Raptor at Ser{sup 792}, was dramatically enhanced in human pancreatic ductal adenocarcinoma (PDAC) cells PANC-1 and MiaPaCa-2 cultured in medium containing physiological concentrations of glucose (5 mM), as compared with parallel cultures in medium with glucose at 25 mM. In physiological glucose, metformin inhibited mTORC1 activation, DNA synthesis and proliferation of PDAC cells stimulated by crosstalk between G protein-coupled receptors and insulin/IGF signaling systems, at concentrations (0.05-0.1 mM) that were 10-100-fold lower than those used in most previous reports. Using siRNA-mediated knockdown of the {alpha}{sub 1} and {alpha}{sub 2} catalytic subunits of AMPK, we demonstrated that metformin, at low concentrations, inhibited DNA synthesis through an AMPK-dependent mechanism. Our results emphasize the importance of using medium containing physiological concentrations of glucose to elucidate the anticancer mechanism of action of metformin in pancreatic cancer cells and other cancer cell types.

  18. Effects of subtoxic concentrations of TiO2 and ZnO nanoparticles on human lymphocytes, dendritic cells and exosome production.

    Science.gov (United States)

    Andersson-Willman, Britta; Gehrmann, Ulf; Cansu, Zekiye; Buerki-Thurnherr, Tina; Krug, Harald F; Gabrielsson, Susanne; Scheynius, Annika

    2012-10-01

    Metal oxide nanoparticles are widely used in the paint and coating industry as well as in cosmetics, but the knowledge of their possible interactions with the immune system is very limited. Our aims were to investigate if commercially available TiO(2) and ZnO nanoparticles may affect different human immune cells and their production of exosomes, nano-sized vesicles that have a role in cell to cell communication. We found that the TiO(2) or ZnO nanoparticles at concentrations from 1 to 100μg/mL did not affect the viability of primary human peripheral blood mononuclear cells (PBMC). In contrast, monocyte-derived dendritic cells (MDDC) reacted with a dose dependent increase in cell death and caspase activity to ZnO but not to TiO(2) nanoparticles. Non-toxic exposure, 10μg/mL, to TiO(2) and ZnO nanoparticles did not significantly alter the phenotype of MDDC. Interestingly, ZnO but not TiO(2) nanoparticles induced a down regulation of FcγRIII (CD16) expression on NK-cells in the PBMC population, suggesting that subtoxic concentrations of ZnO nanoparticles might have an effect on FcγR-mediated immune responses. The phenotype and size of exosomes produced by PBMC or MDDC exposed to the nanoparticles were similar to that of exosomes harvested from control cultures. TiO(2) or ZnO nanoparticles could not be detected within or associated to exosomes as analyzed with TEM. We conclude that TiO(2) and ZnO nanoparticles differently affect immune cells and that evaluations of nanoparticles should be performed even at subtoxic concentrations on different primary human immune cells when investigating potential effects on immune functions. Copyright © 2012 Elsevier Inc. All rights reserved.

  19. Critical micelle concentration of surfactants in aqueous buffered and unbuffered systems

    International Nuclear Information System (INIS)

    Fuguet, Elisabet; Rafols, Clara; Roses, Marti; Bosch, Elisabeth

    2005-01-01

    Critical micelle concentration (CMC) of sodium dodecyl sulphate (SDS), lithium perfluorooctanesulfonate (LPFOS), hexadecyltrimethylammonium bromide (HTAB), tetradecyltrimethylammonium bromide (TTAB), and sodium cholate (SC), surfactants commonly used as pseudostationary phases in micellar electrokinetic chromatography (MEKC), have been determined by means of three different methods: MEKC, spectrophotometry, and conductometry. Determinations have been performed in water, and also in different concentrations of phosphate buffer at pH 7.0. CMC values ranging from 8.08 (water) to 1.99 (50 mM phosphate buffer) mM for SDS, from 7.16 (water) to 2,81 (30 mM phosphate buffer) mM for LPFOS, from 3.77 (water) to 1.93 (20 mM phosphate buffer) mM for TTAB, from 0.91 (water) to ∼0.34 (20 mM phosphate buffer) for HTAB, and around 13 mM (20 mM phosphate buffer) for SC, are obtained. The effect of the electrolyte concentration on the CMC, as well as the linear relationship between the electrolyte counter-ion concentration and the CMC are discussed. This linear relationship provides an easy way for users to estimate the CMC of a MEKC system, at a given electrolyte concentration. A comparison between experimental methods, as well as a discussion about the suitability of a given method for the determination of the CMC for a given surfactant system is also provided

  20. Photovoltaic Systems with and without Radiation Concentrators for Temperate and Tropical Regions

    Directory of Open Access Journals (Sweden)

    Vania Reis de Souza Sant’Anna

    2015-11-01

    Full Text Available The industrial development of solar photovoltaic technology has attracted investors and influenced governments to establish public policies for the sector. The present research consisted of studying, building and testing low concentration solar radiation systems for photovoltaic energy conversion. The study used optical nonimaging parameters for the V-trough type radiation concentrator constructed of anodized aluminum, to reflect and to cool. Designed to concentrate radiation by about two times and consisting of a set of photovoltaic modules connected in parallel, they were modeled in the Laboratory of Energy Area in the Department of Agricultural Engineering of the Federal University of Vicosa, Brazil, at the coordinates 20°45′14′′ S latitude, 42°52′53′′ W longitude and altitude 648.74 m. They were installed to the geographic North, with the same slope as the local latitude. For comparative analysis, it was determined the electrical characteristics for evaluation of the prototype’s performance with and without radiation concentration, the final productivity for cities in tropical and temperate regions and economic analysis for the system. It was concluded that the prototypes allowed for a gain of energy with concentration, about 31.3% more, and therefore a productivity gain for the analyzed cities in, kWh·kWp−1.

  1. APOLLON. Multi-APprOach for high efficiency integrated and inteLLigent cONcentrating PV modules (Systems). Deliverable 7.10. Publication of environmental LCI dataset

    Energy Technology Data Exchange (ETDEWEB)

    Olson, C.L. [ECN Solar Energy, Petten (Netherlands)

    2013-10-15

    This deliverable makes available the life-cycle inventory used to calculate the energy payback time and the carbon footprint of the Apollon final concentrating photovoltaics (CPV) design developed.. The data below relates to one Apollon module. The results are to be published in Environmental Science and Technology, in a paper, 'Sustainability of Materials and Costs of Materials in a Mirror-based Concentrating Photovoltaic System'. Reference is made to the results for the Spectrolab triple junction solar cell in the following two studies: (1) 'Life cycle assessment of high-concentration photovoltaic systems' (Prog. Photovolt: Res. Appl., vol. 21, pp. 379-388, 2013), and (2) 'Life Cycle Analysis of Two New Concentrator PV Systems', in 23rd European Photovoltaic Solar Energy Conference, Valencia, Spain, 2008.

  2. Strontium concentrations in corrosion products from residential drinking water distribution systems.

    Science.gov (United States)

    Gerke, Tammie L; Little, Brenda J; Luxton, Todd P; Scheckel, Kirk G; Maynard, J Barry

    2013-05-21

    The United States Environmental Protection Agency (US EPA) will require some U.S. drinking water distribution systems (DWDS) to monitor nonradioactive strontium (Sr(2+)) in drinking water in 2013. Iron corrosion products from four DWDS were examined to assess the potential for Sr(2+) binding and release. Average Sr(2+) concentrations in the outermost layer of the corrosion products ranged from 3 to 54 mg kg(-1) and the Sr(2+) drinking water concentrations were all ≤0.3 mg L(-1). Micro-X-ray adsorption near edge structure spectroscopy and linear combination fitting determined that Sr(2+) was principally associated with CaCO3. Sr(2+) was also detected as a surface complex associated with α-FeOOH. Iron particulates deposited on a filter inside a home had an average Sr(2+) concentration of 40.3 mg kg(-1) and the associated drinking water at a tap was 210 μg L(-1). The data suggest that elevated Sr(2+) concentrations may be associated with iron corrosion products that, if disturbed, could increase Sr(2+) concentrations above the 0.3 μg L(-1) US EPA reporting threshold. Disassociation of very small particulates could result in drinking water Sr(2+) concentrations that exceed the US EPA health reference limit (4.20 mg kg(-1) body weight).

  3. Influence of red blood cell concentrations on the measurement of turbulence using hot-film anemometer.

    Science.gov (United States)

    Sallam, A M; Hwang, N H

    1983-11-01

    Measurement of local velocity fluctuations was made with an L-shaped conical hot-film probe in a submerged circular jet. The experiment was carried out in solutions of washed human red blood cells (RBC) in a phosphate buffer solution (PBS), at hematocrit concentrations (Ht percent) of 10, 19, 29, and 38 percent. The viscosity of the testing solutions was kept at 3.2 c.p. by adding proper amount of dextran. The experiment was conducted at Reynolds numbers (NR) 674, 963, 1255 and 1410, based on the jet exit velocity and exit diameter. Statistical analyses were performed on the recorded instantaneous velocity signals to obtain the root-mean-square (rms) values, the probability density functions (PDF) and the power spectral density functions (PSDF) of the signals. Within the range tested, we noticed an incidental rise in rms values at 19 to 29 Ht percent for NR = 963 similar to those reported earlier in the literature. Further analyses using PDF and PSDF, however, showed neither a trend nor any physical significance of this rise. Based on the analyses of both the PDF and the PSDF, we believe that the incidental rise in rms value can be partially attributed to the high spikes registered by the probe in a high RBC concentrations fluid flow. The bombardment of RBC on the probe thermal boundary layer may cause a characteristic change in the probe response to certain flow phenomenon, at least within the Reynolds number range used in this study.(ABSTRACT TRUNCATED AT 250 WORDS)

  4. A Reliable and Reproducible Model for Assessing the Effect of Different Concentrations of α-Solanine on Rat Bone Marrow Mesenchymal Stem Cells

    Directory of Open Access Journals (Sweden)

    Adriana Ordóñez-Vásquez

    2017-01-01

    Full Text Available Αlpha-solanine (α-solanine is a glycoalkaloid present in potato (Solanum tuberosum. It has been of particular interest because of its toxicity and potential teratogenic effects that include abnormalities of the central nervous system, such as exencephaly, encephalocele, and anophthalmia. Various types of cell culture have been used as experimental models to determine the effect of α-solanine on cell physiology. The morphological changes in the mesenchymal stem cell upon exposure to α-solanine have not been established. This study aimed to describe a reliable and reproducible model for assessing the structural changes induced by exposure of mouse bone marrow mesenchymal stem cells (MSCs to different concentrations of α-solanine for 24 h. The results demonstrate that nonlethal concentrations of α-solanine (2–6 μM changed the morphology of the cells, including an increase in the number of nucleoli, suggesting elevated protein synthesis, and the formation of spicules. In addition, treatment with α-solanine reduced the number of adherent cells and the formation of colonies in culture. Immunophenotypic characterization and staining of MSCs are proposed as a reproducible method that allows description of cells exposed to the glycoalkaloid, α-solanine.

  5. Rinsing paired-agent model (RPAM) to quantify cell-surface receptor concentrations in topical staining applications of thick tissues

    Science.gov (United States)

    Xu, Xiaochun; Wang, Yu; Xiang, Jialing; Liu, Jonathan T. C.; Tichauer, Kenneth M.

    2017-06-01

    Conventional molecular assessment of tissue through histology, if adapted to fresh thicker samples, has the potential to enhance cancer detection in surgical margins and monitoring of 3D cell culture molecular environments. However, in thicker samples, substantial background staining is common despite repeated rinsing, which can significantly reduce image contrast. Recently, ‘paired-agent’ methods—which employ co-administration of a control (untargeted) imaging agent—have been applied to thick-sample staining applications to account for background staining. To date, these methods have included (1) a simple ratiometric method that is relatively insensitive to noise in the data but has accuracy that is dependent on the staining protocol and the characteristics of the sample; and (2) a complex paired-agent kinetic modeling method that is more accurate but is more noise-sensitive and requires a precise serial rinsing protocol. Here, a new simplified mathematical model—the rinsing paired-agent model (RPAM)—is derived and tested that offers a good balance between the previous models, is adaptable to arbitrary rinsing-imaging protocols, and does not require calibration of the imaging system. RPAM is evaluated against previous models and is validated by comparison to estimated concentrations of targeted biomarkers on the surface of 3D cell culture and tumor xenograft models. This work supports the use of RPAM as a preferable model to quantitatively analyze targeted biomarker concentrations in topically stained thick tissues, as it was found to match the accuracy of the complex paired-agent kinetic model while retaining the low noise-sensitivity characteristics of the ratiometric method.

  6. Reducing surface water total and methyl mercury concentrations and bioavailability using a coagulation-wetland system

    Science.gov (United States)

    Kraus, T. E.; Fleck, J.; Henneberry, Y. K.; Stumpner, E. B.; Krabbenhoft, D. P.; Bachand, P.; Randall, P.

    2013-12-01

    With the recent passage of laws regulating concentrations and loads of mercury (Hg) in surface waters, there is a need to develop management practices that will reduce the export of Hg from both point and non-point sources. Coagulation with metal based salts to remove particles and dissolved organic matter (DOM) from solution is a practice commonly employed by drinking water utilities. Because dissolved Hg is associated with particles and DOM, it follows that Hg should also be removed during the coagulation process and end up associated with the organo-metal precipitate, termed flocculate (floc). The effectiveness of iron- and aluminum-based coagulants for removing both inorganic and methyl mercury (IHg and MeHg, respectively) from solution was demonstrated in laboratory studies conducted on agricultural drainage waters of the Sacramento-San Joaquin Delta: dissolved concentrations of MeHg decreased by 80% while IHg decreased by 97% following coagulation. To test the field application of this technology, samples were collected from the inflows and outflows of wetland treatment cells constructed in the central Delta of California. This replicated field experiment includes three replicates each of three inflow waters treatments: (1) iron sulfate addition, (2) polyaluminum chloride addition, and (3) untreated controls. Water entering and exiting the nine treatment cells was sampled approximately monthly over a 1-year period for total Hg and MeHg in both the dissolved and particulate aqueous phases. Initial results confirm that coagulant addition is removing Hg (total and methyl, particulate and dissolved) from solution and sequestering it in the floc. Seasonal effects on DOM concentration and other factors appear to effect whether passage through the wetland cells alters surface water dissolved organic carbon (DOC) and Hg concentrations. Related studies will examine whether the presence of the floc affects the production and fate of MeHg within the wetland cells. If

  7. Genotoxic effects of daily personal exposure to particle mass and number concentrations on buccal cells

    Science.gov (United States)

    de Almeida, Daniela S.; da Costa, Silvano César; Ribeiro, Marcos; Moreira, Camila A. B.; Beal, Alexandra; Squizzato, Rafaela; Rudke, Anderson Paulo; Rafee, Sameh Adib Abou; Martins, Jorge A.; Palioto, Graciana Freitas; Kumar, Prashant; Martins, Leila D.

    2018-03-01

    The aim of this study is to assess personal exposure to Particle Number Concentrations (PNC) in four size ranges between 0.3 and 10 μm, and particulate matter (PM1; PM2.5; PM4; PM10) in order to evaluate possible genotoxic effects through a comet assay in buccal cells. A convenience cohort of 30 individuals from a Brazilian medium-sized city was selected. These individuals aged between 20 and 61 and worked in typical job categories (i.e., administrative, commerce, education, general services and transport). They were recruited to perform personal exposure measurements during their typical daily routine activities, totaling 240 h of sampling. The 8-h average mass concentrations in air for volunteers ranged from 2.4 to 31.8 μg m-3 for PM1, 4.2-45.1 μg m-3 for PM2.5, 7.9-66.1 μg m-3 for PM4 and from 23.1 to 131.7 μg m-3 for PM10. The highest PNC variation was found for 0.3-0.5 range, between 14 and 181 particles cm-3, 1 to 14 particles cm-3 for the 0.5-1.0 range, 0.2 to 2 particles cm-3 for the 1.0-2.5 range, and 0.06 to 0.7 particles cm-3 for the 2.5-10 range. Volunteers in the 'education' category experienced the lowest inhaled dose of PM2.5, as opposed to those involved in 'commercial' activities with the highest doses for PM10 (1.63 μg kg-1 h-1) and PM2.5 (0.61 μg kg-1 h-1). The predominant cause for these high doses was associated with the proximity of the workplace to the street and vehicle traffic. The comet assay performed in buccal cells indicated that the volunteers in 'commerce' category experienced the highest damage to their DeoxyriboNucleic Acid (DNA) compared with the control category (i.e. 'education'). These results indicate the variability in personal exposure of the volunteers in different groups, and the potential damage to DNA was much higher for those spending time in close proximity to the vehicle sources (e.g. commercial services) leading to exposure to a higher fraction of fine particles. This study builds understanding on the exposure

  8. Design and implementation of a 38 kW dish-Stirling concentrated solar power system

    Science.gov (United States)

    Yan, J.; Peng, Y. D.; Cheng, Z. R.; Liu, F. M.; Tang, X. H.

    2017-11-01

    Dish-Stirling concentrated solar power system (DS-CSP) is an important pathway for converting solar energy into electricity at high efficiency. In this study, a rated power 38 kW DS-CSP system was developed (installed in Xiangtan Electric Manufacturing Group). The heat engine adopted the alpha-type four cylinders double-acting Stirling engine (Stirling Biopower Flexgen S260). The absorber flux distribution simulation was conducted using ray tracing method and then the 204 m2 parabolic dish concentrator system (diameter is 17.70 m and focal length is 9.49 m) with single concentrator plus single pillar supporting has been designed and built. A water-cooled disc target and an absorber imitation device were adopted to test the tracking performance of the dish concentrator system, homogeneity of the focal spot and flux distribution of the absorber. Finally, the S260 Stirling engine was installed on the focal position of the dish concentrator and then the net output power date of the 38 kW DS-CSP system was tested. The absorber overheating problem on the DS-CSP system performance was discussed when the DS-CSP system was installed in different locations. The testing result shows that this system achieved the net output power of 38 kW and solar-to-electricity efficiency (SEE) of 25.3% with the direct normal irradiation (DNI) at 750 W/m2. The net output power can further increase to 40.5 kW with the SEE of 26.6% when the DNI reaches up to the maximum of 761 W/m2. The net output power of the 38 kW DS-CSP system has a linear function relationship with the DNI. The fitting function is Net power output=0.1003×DNI-36.129, where DNI is at the range of 460∼761 W/m2. This function could be used to predict the amount of the 38 kW DS-CSP system annual generation power.

  9. Equilibrium concentration of radionuclides in cement/groundwater/carbon steel system

    International Nuclear Information System (INIS)

    Keum, D. K.; Cho, W. J.; Hahn, P. S.

    1997-01-01

    Equilibrium concentration of major elements in an underground repository with a capacity of 100,000 drums have been simulated using the geochemical computer code (EQMOD). The simulation has been carried out at the conditions of pH 12 to 13.5, and Eh 520 and -520 mV. Solubilities of magnesium and calcium decrease with the increase of pH. The solubility of iron increases with pH at Eh -520 mV of reducing environment, while it almost entirely exists as the precipitate of Fe(OH) 3 (s) at Eh 520 mV of oxidizing environment. All of cobalt and nickel are predicted to be dissolved in the liquid phase regardless of pH since the solubility limit is greater than the total concentration. In the case of cesium and strontium, all forms of both ions are present in the liquid phase because they have negligible sorption capacity on cement and large solubility under disposal atmosphere. And thus the total concentration determines the equilibrium concentration. Adsorbed amounts of iodide and carbonate are dependent on adsorption capacity and adsorption equilibrium constant. Especially, the calcite turns out to be a solubility-limiting phase on the carbonate system. In order to validate the model, the equilibrium concentrations measured for a number of systems which consist of iron, cement, synthetic groundwater and radionuclides are compared with those predicted by the model. The concentrations between the model and the experiment of nonadsorptive elements - cesium, strontium, cobalt, nickel and iron, are well agreed. It indicates that the assumptions and the thermodynamic data in this work are valid. Using the adsorption equilibrium constant as a free parameter, the experimental data of iodide and carbonate have been fitted to the model. The model is in a good agreement with the experimental data of the iodide system. (author)

  10. Determination of the critical micelle concentration in simulations of surfactant systems

    International Nuclear Information System (INIS)

    Santos, Andrew P.; Panagiotopoulos, Athanassios Z.

    2016-01-01

    Alternative methods for determining the critical micelle concentration (cmc) are investigated using canonical and grand canonical Monte Carlo simulations of a lattice surfactant model. A common measure of the cmc is the “free” (unassociated) surfactant concentration in the presence of micellar aggregates. Many prior simulations of micellizing systems have observed a decrease in the free surfactant concentration with overall surfactant loading for both ionic and nonionic surfactants, contrary to theoretical expectations from mass-action models of aggregation. In the present study, we investigate a simple lattice nonionic surfactant model in implicit solvent, for which highly reproducible simulations are possible in both the canonical (NVT) and grand canonical (μVT) ensembles. We confirm the previously observed decrease of free surfactant concentration at higher overall loadings and propose an algorithm for the precise calculation of the excluded volume and effective concentration of unassociated surfactant molecules in the accessible volume of the solution. We find that the cmc can be obtained by correcting the free surfactant concentration for volume exclusion effects resulting from the presence of micellar aggregates. We also develop an improved method for determination of the cmc based on the maximum in curvature for the osmotic pressure curve determined from μVT simulations. Excellent agreement in cmc and other micellar properties between NVT and μVT simulations of different system sizes is observed. The methodological developments in this work are broadly applicable to simulations of aggregating systems using any type of surfactant model (atomistic/coarse grained) or solvent description (explicit/implicit)

  11. Determination of the critical micelle concentration in simulations of surfactant systems

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Andrew P.; Panagiotopoulos, Athanassios Z., E-mail: azp@princeton.edu [Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544 (United States)

    2016-01-28

    Alternative methods for determining the critical micelle concentration (cmc) are investigated using canonical and grand canonical Monte Carlo simulations of a lattice surfactant model. A common measure of the cmc is the “free” (unassociated) surfactant concentration in the presence of micellar aggregates. Many prior simulations of micellizing systems have observed a decrease in the free surfactant concentration with overall surfactant loading for both ionic and nonionic surfactants, contrary to theoretical expectations from mass-action models of aggregation. In the present study, we investigate a simple lattice nonionic surfactant model in implicit solvent, for which highly reproducible simulations are possible in both the canonical (NVT) and grand canonical (μVT) ensembles. We confirm the previously observed decrease of free surfactant concentration at higher overall loadings and propose an algorithm for the precise calculation of the excluded volume and effective concentration of unassociated surfactant molecules in the accessible volume of the solution. We find that the cmc can be obtained by correcting the free surfactant concentration for volume exclusion effects resulting from the presence of micellar aggregates. We also develop an improved method for determination of the cmc based on the maximum in curvature for the osmotic pressure curve determined from μVT simulations. Excellent agreement in cmc and other micellar properties between NVT and μVT simulations of different system sizes is observed. The methodological developments in this work are broadly applicable to simulations of aggregating systems using any type of surfactant model (atomistic/coarse grained) or solvent description (explicit/implicit)

  12. Hemicellulosic Ethanol Production by Immobilized Wild Brazilian Yeast Scheffersomyces shehatae UFMG-HM 52.2: Effects of Cell Concentration and Stirring Rate.

    Science.gov (United States)

    Antunes, F A F; Santos, J C; Chandel, A K; Milessi, T S S; Peres, G F D; da Silva, S S

    2016-02-01

    The use of sugarcane bagasse hemicellulosic hydrolysates presents an interesting alternative to second generation (2G) ethanol production. Techniques to enhance the fermentation process, e.g., the use of immobilized cells, is one of the key factors for efficient production. Here, the effect of two important parameters (cell concentration in immobilized system and stirring rate) on the 2G ethanol production using the wild Brazilian yeast S. shehatae UFMG-HM 52.2 immobilized in calcium alginate matrix are presented. A 2(2) full factorial design of experiments was carried out to evaluate the effect of cell concentrations in sodium alginate solution for immobilized bead production (3.0, 6.0, and 9.0 g/L) and stirring rate (150, 200, and 250 rpm) for 2G ethanol production. Statistical analysis showed that the use of both variables at low levels enhanced ethanol yield (YP/S). Under these process conditions, YP/S of 0.31 g/g and ethanol productivity (Qp) of 0.12 g/L h were achieved. Results showed the potential of this immobilized yeast in 2G ethanol production from C5 sugars and demonstrate the importance of adequate cell concentration in immobilized systems, a finding that stands to increase bioprocesses yields and productivity.

  13. Research on the detection system of liquid concentration base on birefringence light transmission method

    Science.gov (United States)

    Li, Tianze; Zhang, Xia; Hou, Luan; Jiang, Chuan

    2010-10-01

    The characteristics of the beam transmitting in the optical fiber and the liquid medium are analyzed in this paper. On this basis, a new type of semiconductor optical position sensitive detector is used for a receiving device, a light transmission method of birefringence is presented,and a set of opto-electrical detection system which is applied to detect liquid concentration is designed. The system is mainly composed of semiconductor lasers,optical systems, Psd signal conditioning circuit, Single-chip System, A/D conversion circuit and display circuit. Through theoretical analysis and experimental simulations, the accuracy of this system has been verified. Some main factors affecting the test results are analyzed detailedly in this paper. The experiments show that the temperature drift and the light intensity have a very small impact on this system. The system has some advantages, such as the simple structure, high sensitivity, good stability, fast response time, high degree of automation, and so on. It also can achieve the real-time detection of liquid concentration conveniently and accurately. The system can be widely applied in chemical, food, pharmacy and many other industries. It has broad prospects of application.

  14. High concentrations of genistein exhibit pro-oxidant effects in primary muscle cells through mechanisms involving 5-lipoxygenase-mediated production of reactive oxygen species.

    Science.gov (United States)

    Chen, Wei; Lin, Ying Cai; Ma, Xian Yong; Jiang, Zong Yong; Lan, Si Ping

    2014-05-01

    Genistein, a typical soy isoflavone, is an important antioxidant for improving human health and animal production but the compound possesses some pro-oxidant potential. In order to explore the latter, the dose-response relationship of various concentrations of genistein on both cellular proliferation and the redox system were examined. The proliferation of primary muscle cells was promoted by a low concentration of genistein but was inhibited by high concentrations, which also enhanced lipid oxidation and suppressed membrane fluidity. By selecting a high concentration (200 μM) as a pro-oxidant treatment, the mechanism underlying the pro-oxidant function of genistein was then explored. The generation of intracellular reactive oxygen species (ROS) was stimulated by 200 μM genistein, with inhibited expression of NADPH oxidase 4 and cyclooxygenase 1 and 2 as well as increased activity of the glutathione redox system. The cellular expression of 5-lipoxygenase, however, was up-regulated by 200 μM genistein and the addition of 5-lipoxygenase inhibitor (Zileuton) decreased genistein-induced intracellular ROS level, close to that from the addition of the ROS scavenger, N-acetylcysteine. It is concluded that higher concentrations of genistein exert pro-oxidant potential in the primary muscle cells through enhancing ROS production in a 5-lipoxygenase-dependent manner. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. A Comparison Of A Solar Power Satellite Concept To A Concentrating Solar Power System

    Science.gov (United States)

    Smitherman, David V.

    2013-01-01

    A comparison is made of a Solar Power Satellite concept in geostationary Earth orbit to a Concentrating Solar Power system on the ground to analyze overall efficiencies of each infrastructure from solar radiance at 1