bluuebunny/crossref_metadata_2025 huggingface dataset:
Foreign Direct Investment and Institutional Diversity in Trade Agreements: Credibility, Commitment, and Economic Flows in the Developing World, 1971–2007
Authors: Büthe Tim , Milner Helen V.
Published: December 2013

International trade agreements lead to more foreign direct investment (FDI) in developing countries. This article examines the causal mechanisms underpinning this trade-investment linkage by asking whether institutional features of preferential trade agreements (PTAs), which allow governments to make more credible commitments to protect foreign investments, indeed result in greater FDI. The authors explore three institutional differences. First, they examine whether PTAs that have entered into force lead to greater FDI than PTAs that have merely been negotiated and signed, since only the former constitute a binding commitment under international law. Second, they ask whether trade agreements that have investment clauses lead to greater FDI. Third, they consider whether PTAs with dispute-settlement mechanisms lead to greater FDI. Analyses of FDI flows into 122 developing countries from 1971 to 2007 show that trade agreements that include stronger mechanisms for credible commitment induce more FDI. Institutional diversity in international agreements matters.
Development of an adaptive neural‐fuzzy inference system based meta‐model for estimating lightning related failures in polluted environments
Authors: Shariatinasab Reza , Ghayur Safar Jalil , Akafi Mobarakeh Mohsen
Published: December 2013

Owing to the random nature of the lightning phenomenon, the statistical based methods such as Monte Carlo simulation are the best tool to perform the lightning‐related studies. However, Monte Carlo simulation is complex and time consuming, especially, for larger networks where a lot of regions must be investigated, separately. Although some researches have been carried out to evaluate the lightning flashover outage rates based on artificial intelligence (AI) techniques, but, so far, any work has not been reported to perform a risk assessment of lightning surges by means of AI. This study presents a meta‐model based on adaptive neural‐fuzzy inference system (ANFIS) that can be utilised to perform the lightning‐related risk analysis with a good accuracy. The inputs of ANFIS are tower footing resistance, critical flashover voltage and the rate of lightning occurrence; and its outputs include the failure risk of both the insulation and arrester. The trained ANFIS can be very efficient in terms of time and computational resources for the further analysis, like placement of arresters or insulation coordination studies, on the electrical network on which the training is performed. To demonstrate the effectiveness of the ANFIS meta‐model, an optimisation method, based on genetic algorithm, has been implemented in order to find the optimum location of a specified set of line arresters on power network. Also, in order to consider the environmental condition, that is, pollution and altitude, a new method to determine the importance of each node of interest in protection is introduced.
Thermodiffusion in concentrated ferrofluids: A review and current experimental and numerical results on non-magnetic thermodiffusion
Authors: Sprenger Lisa , Lange Adrian , Odenbach Stefan
Published: December 2013

Ferrofluids are colloidal suspensions consisting of magnetic nanoparticles dispersed in a carrier liquid. Their thermodiffusive behaviour is rather strong compared to molecular binary mixtures, leading to a Soret coefficient (ST) of 0.16 K−1. Former experiments with dilute magnetic fluids have been done with thermogravitational columns or horizontal thermodiffusion cells by different research groups. Considering the horizontal thermodiffusion cell, a former analytical approach has been used to solve the phenomenological diffusion equation in one dimension assuming a constant concentration gradient over the cell's height. The current experimental work is based on the horizontal separation cell and emphasises the comparison of the concentration development in different concentrated magnetic fluids and at different temperature gradients. The ferrofluid investigated is the kerosene-based EMG905 (Ferrotec) to be compared with the APG513A (Ferrotec), both containing magnetite nanoparticles. The experiments prove that the separation process linearly depends on the temperature gradient and that a constant concentration gradient develops in the setup due to the separation. Analytical one dimensional and numerical three dimensional approaches to solve the diffusion equation are derived to be compared with the solution used so far for dilute fluids to see if formerly made assumptions also hold for higher concentrated fluids. Both, the analytical and numerical solutions, either in a phenomenological or a thermodynamic description, are able to reproduce the separation signal gained from the experiments. The Soret coefficient can then be determined to 0.184 K−1 in the analytical case and 0.29 K−1 in the numerical case. Former theoretical approaches for dilute magnetic fluids underestimate the strength of the separation in the case of a concentrated ferrofluid.
Protein structural ensembles are revealed by redefining X-ray electron density noise
Authors: Lang P. Therese , Holton James M. , Fraser James S. , Alber Tom
Published: December 2013

Significance

This work presents computational solutions to two longstanding problems in protein structure determination using X-ray crystallography. Together, these methods reveal that the electron density threshold for discovering alternative protein and ligand conformations is much lower than the standard cutoff for structural modeling. Three broad applications illustrate that the features present in weak electron density can reveal important, unanticipated conformational heterogeneity in proteins. The methods introduced here help convert X-ray crystallography from the principal technique to obtain “snapshots” of biological molecules to an approach that also can reveal the signatures of molecular motions that are potentially important for function. These advances have broad implications for developing drugs and understanding protein mechanisms.
On Near Optimal Lattice Quantization of Multi‐Dimensional Data Points
Authors: Finckh M. , Dammertz H. , Lensch H. P. A.
Published: December 2013

One of the most elementary application of a lattice is the quantization of real‐valued s‐dimensional vectors into finite bit precision to make them representable by a digital computer. Most often, the simple s‐dimensional regular grid is used for this task where each component of the vector is quantized individually. However, it is known that other lattices perform better regarding the average quantization error. A rank‐1 lattices is a special type of lattice, where the lattice points can be described by a single s‐dimensional generator vector. Further, the number of points inside the unit cube [0, 1)s is arbitrary and can be directly enumerated by a single one‐dimensional integer value. By choosing a suitable generator vector the minimum distance between the lattice points can be maximized which, as we show, leads to a nearly optimal mean quantization error. We present methods for finding parameters for s‐dimensional maximized minimum distance rank‐1 lattices and further show their practical use in computer graphics applications.
Achieving Quasi-Isothermal Air Compression With Multistage Compressors for Large-Scale Energy Storage
Authors: Wang Kai , Li Peiwen , Arabyan Ara
Published: December 2013

The round trip efficiency of compressed air for energy storage is greatly limited by the significant increase in the temperature of the compressed air (and the resulting heat loss) in high-ratio adiabatic compression. This paper introduces a multi-stage compression scheme with low-compression-ratio compressors and inter-compressor natural convection cooling resulting in a quasi-isothermal compression process that can be useful for large-scale energy storage. When many low pressure ratio compressors work inline, a high overall compression ratio can be achieved with high efficiency. The quasi-isothermally compressed air can then be expanded adiabatically in turbines to generate power with the addition of thermal energy, from either fuel or a solar thermal source. This paper presents mathematical models of such an energy storage system and discusses its round-trip performance with different operating schemes.
Experimental Study on Performance of a Residential Combined Cooling, Heating and Power System Under Varying Building Load
Authors: Qian Suxin , Gluesenkamp Kyle , Hwang Yunho , Radermacher Reinhard
Published: December 2013

Trigeneration systems are closely associated with sorption cooling technology because prime mover waste heat can be recovered to produce cooling. The working pair and cycle type of the sorption cooling system needs to be matched to the waste heat temperature of the prime mover, as well as with the capacity and application of the trigeneration system. A residential trigeneration system with a 4 kWelec internal combustion engine, a 220 gallon (830 L) hot water tank and a 3 kW adsorption chiller powered by 70°C waste heat with separate sensible and latent cooling control strategy is presented in this study. Transient experiments were conducted under 5 day long hot water and space cooling load profiles from a simulated house to evaluate the performance from a practical perspective. The fuel consumption was measured and compared with that of two baseline systems. An analytical criterion was derived and discussed to further evaluate the trigeneration system with different loads under different climates. It was found that the presented residential trigeneration system could save about 30% of fuel consumption compared with conventional off-grid operation mode, but is not more fuel efficient than the conventional on-grid and vapor compression cooling combination.
Design Point for Predicting Year-Round Performance of Solar Parabolic Trough Concentrator Systems
Authors: Wirz Men , Roesle Matthew , Steinfeld Aldo
Published: December 2013

Thermal efficiencies of the solar field of two different parabolic trough concentrator (PTC) systems are evaluated for a variety of operating conditions and geographical locations, using a detailed 3D heat transfer model. Results calculated at specific design points are compared to yearly average efficiencies determined using measured direct normal solar irradiance (DNI) data as well as an empirical correlation for DNI. It is shown that the most common choices of operating conditions at which solar field performance is evaluated, such as the equinox or the summer solstice, are inadequate for predicting the yearly average efficiency of the solar field. For a specific system and location, the different design point efficiencies vary significantly and differ by as much as 11.5% from the actual yearly average values. An alternative simple method is presented of determining a representative operating condition for solar fields through weighted averages of the incident solar radiation. For all tested PTC systems and locations, the efficiency of the solar field at the representative operating condition lies within 0.3% of the yearly average efficiency. Thus, with this procedure, it is possible to accurately predict year-round performance of PTC systems using a single design point, while saving computational effort. The importance of the design point is illustrated by an optimization study of the absorber tube diameter, where different choices of operating conditions result in different predicted optimum absorber diameters.
Heat Loss Experiments on a Non-Evacuated Parabolic Trough Receiver Employing a Thermally Insulating Layer in the Annular Gap
Authors: Al-Ansary Hany , Zeitoun Obida
Published: December 2013

Parabolic trough collectors are economically and technically attractive options for process heat applications that require temperatures in excess of 200 °C. One of the reasons is that low-cost non-evacuated receivers are used in this type of application. However, at higher temperatures, the performance of non-evacuated receivers deteriorates considerably due to excessive radiation and natural convection losses. A new idea had been preliminarily investigated by the authors both numerically and experimentally. The idea was to introduce a thermally insulating layer to the part of the receiver’s annular gap that does not receive concentrated sunlight from the parabolic mirrors, and the results had been quite promising. This paper presents additional, more extensive experiments on this concept. In these experiments, a cartridge heater is inserted along the axis of the receiver tube of a non-evacuated receiver. The heater is surrounded by a conductive material to ensure uniform heating of the receiver tube. A number of thermocouples are affixed near the inner surface of the receiver as well as on the outer surface of the glass envelope to monitor temperature uniformity. Two sets of experiments are then conducted, one with the insulating layer, and the other without. In each set, the power input is set to a certain level and the receiver temperature is measured once steady state conditions are attained. The power level is then increased, and the measurements are repeated. The heat loss values from each set are compared to determine whether adding the insulating layer enhances receiver performance. Results show that a reduction in heat loss of as much as 15% can be achieved using this design, and collector efficiency can increase by up to about 6%. However, it was also found that the extent of improvement in collector efficiency depends on the operating temperature and direct normal irradiance, with the improvement being more significant at higher temperature applications and at low direct normal irradiance.
Modeling and Testing of a Portable Thermal Battery
Authors: Taylor Robert A. , Chung Derek , Morrison Karl , Hawkes Evatt
Published: December 2013

Portable energy storage will be a key challenge if electric vehicles become a large part of our future transportation system. A big limiting factor is vehicle range. Range can be further limited if heating and air conditioning systems are powered by the electric vehicle’s batteries. The use of electricity for HVAC can be minimized if a thermal battery can be substituted as the energy source to provide sufficient cabin heating and cooling. The aim of this project was to model, design, and fabricate a thermal storage battery for electric vehicles. Since cost and weight are the main considerations for a vehicular application — every attempt was made to minimize them in this design. Thus, the final thermal battery consists of a phase change material Erythritol (a sugar alcohol commonly used as artificial sweetener) as the storage medium sealed in an insulated, stainless steel cooking pot. Heat exchange to the thermal battery is accomplished via water (or low viscosity engine oil) which is pushed through a copper coil winding. A CFD model was used to determine the geometry (winding radius and number of coils) and flow conditions necessary to create adequate heat transfer. Testing of the fabricated design indicates that the prototype thermal battery module losses less than 5% per day and can provide enough heat to meet the demand of cruising passenger vehicle for up to 1 hour of full heating on a cold day. Other metrics, such as $/kJ and kJ/kg, are competitive with Lithium ion batteries for our prototype.
Environmental Impact Assessment of an Anaerobic Codigestion System in Western New York State
Authors: Rankin Matthew J. , Trabold Thomas A. , Blythe Robert
Published: December 2013

Anaerobic codigestion of dairy manure and food-based feedstocks reflects a cradle-to-cradle approach to organic waste management. Given both of their abundance throughout New York State, waste-to-energy processes represent promising waste management strategies. The existing waste-to-energy literature has not yet fully realized the environmental impacts associated with displaced grid electricity generation and feedstock-hauling emissions on the net environmental impact of centralized codigestion facilities. The key objective of this study is to provide a comprehensive environmental impact assessment with the purpose of understanding the existing environmental status of centralized codigestion facilities. Real-time data from an operational codigestion facility located in Western New York State was used to conduct this environmental impact statement. A comprehensive inventory of greenhouse gas emissions associated with renewable electricity production at the codigestion facility was developed using the Emissions & Generation Resource Integrated Database (eGRID) (U.S. EPA), while emissions associated with feedstock hauling were quantified using the fuel life-cycle approach developed by the Greenhouse gases, Regulated Emissions, and Energy use in Transportation model (GREET) (U.S. DOE). With each of the emissions models used for this analysis, it was determined that the net environmental impact associated with hauling food-related feedstocks from the many locations throughout the Northeast U.S. region would be acceptably low, and thus could be part of future sustainable development of centralized codigestion facilities.
Probabilistic Analysis to Quantify Optical Performance and Error Budgets for Next Generation Heliostats
Authors: Christian Joshua , Moya Adam , Ho Clifford , Andraka Charles , Yuan James
Published: December 2013

Current heliostats cost ∼$200/m2 of reflective area and are estimated to contribute up to 50% of the total solar power tower plant costs. A drastic overall cost reduction is required in order for concentrated solar thermal power to be economically viable. The Department of Energy has set forth the SunShot initiative targeting a levelized cost of energy (LCOE) of $0.06/kWh by the year 2020. The cost of each heliostat must be brought down to an estimated $75/m2 to achieve this rigorous goal. One of the driving aspects of heliostat design and cost are the heliostat optical errors. At the moment, it is relatively unclear about the amount of error that can be present in the system while still maintaining low cost and high optical accuracy. The optical errors present on heliostat mirror surfaces directly influence the plant LCOE by causing beam spillage. This can result in an increase in the number of heliostats, an increased receiver size, and decreased thermal efficiency. Assuming a fixed heliostat cost of $75/m2, the effects of optical errors on LCOE are evaluated within the software DELSOL. From a probabilistic analysis, beam quality errors (i.e. slope error, alignment errors, etc.) are shown to have more importance on the LCOE than tracking errors. This determination results in a realization that the tracking errors and beam quality errors can be combined into a “bundled” root-sum-square (RSS) error value. A “bundled” error value of 2 mrad results in an LCOE of $0.06/kWh. This “bundled” value is the basis for a new optical error budget and is decomposed into five individual errors. These five errors can be used as design specifications for new generation heliostats.
Solar House as an Educational Tool for the Newly Established Renewable Energy Engineering Program
Authors: Wang Xingwu , Tang Jianxin , Leigh Wallace
Published: December 2013

This paper introduces the newly established renewable energy engineering program at Alfred University (AU) and a solar house project used as an educational tool for this program. Topics include solar energy harvesting and adaptation of solar systems, engineering calculations/simulation, and global collaboration and marketing.
Factors Influencing Farmers’ Perceived Values of Solar Houses in China: A Focus Group Study in Chongqing
Authors: Li Xuesong , Wang Xingwu
Published: December 2013

Solar houses are important for Chinese farmers to improve quality of life. What are the farmers’ perceived values (FPVs)? In this paper, we report a focus group study in Chongqing, China. Four constructs are considered in the FPV model: economic, quality, social and emotional values. The most important construct is the economic value and the second one is the quality value. Between social and emotional values, this study cannot yield the proper ranking for the third and fourth places.
Thermodynamic Analysis of a Central Heating System Combing the Urban Heat Network With Geothermal Energy
Authors: Wang Xiao , Fu Lin , Zhao Xiling , Liu Hua
Published: December 2013

In recent years, with the continuous urban expansion, the central heating sources are commonly insufficient in the areas of Northern China. Besides, the increasing heat transfer temperature difference results in more and more exergy loss between the primary heat network and the secondary heat network. This paper introduces a new central heating system which combines the urban heat network with geothermal energy (CHSCHNGE). In this system, the absorption heat exchange unit, which is composed of an absorption heat pump and a water to water heat exchanger, is as alternative to the conventional water to water heat exchanger at the heat exchange station, and the doing work ability of the primary heat network is utilized to drive the absorption heat pump to extract the shallow geothermal energy. In this way, the heat supply ability of the system will be increased with fewer additional energy consumptions. Since the water after driving the absorption heat pump has high temperature, it can continue to heat the supply water coming from the absorption heat pump. As a result, the water of the primary heat network will be stepped cooled and the exergy loss will be reduced. In this study, the performance of the system is simulated based on the mathematical models of the heat source, the absorption heat exchange unit, the ground heat exchanger and the room. The thermodynamic analyses are performed for three systems and the energy efficiency and exergy efficiency are compared. The results show that (a) the COP of the absorption heat exchange unit is 1.25 and the heating capacity of the system increases by 25%, which can effectively reduce the requirements of central heating sources; (b) the PER of the system increases 14.4% more than that of the conventional co-generation central heating system and 54.1% more than that of the ground source heat pump system; (c) the exergy efficiency of the CHSCHNGE is 17.6% higher than that of the conventional co-generation central heating system and 45.6% higher than that of the ground source heat pump system.
Novel Non-Concentrated Solar Collector for Solar-Powered Chemical Reactions
Authors: Real Daniel , Hotz Nico
Published: December 2013

The purpose of this study is the proof that non-concentrating solar-thermal collectors can supply the thermal energy needed to power endothermic chemical reactions such as steam reforming of alcoholic (bio-) fuels. Traditional steam reformers require the combustion of up to 50% of the primary fuel to enable the endothermic reforming reaction. Our goal is to use a selective solar absorber coating on top of a collector-reactor surrounded by vacuum insulation. For methanol reforming, a reaction temperature of 220–250°C is required for effective methanol-to-hydrogen conversion. A multilayer absorber coating (TiNOX) is used, as well as a turbomolecular pump to reach ultra-high. The collector-reactor is made of copper tubes and plates and a Cu/ZnO/Al2O3 catalyst is integrated in a porous ceramic structure towards the end of the reactor tube. The device is tested under 1000 W/m2 solar irradiation (using an ABB class solar simulator, air mass 1.5).

Numerical and experimental results show that convective and conductive heat losses are eliminated at vacuum pressures of <10−4 Torr. By reducing radiative losses through chemical polishing of the non-absorbing surfaces, the methanol-water mixture can be effectively heated to 240–250°C and converted to hydrogen-rich gas mixture. For liquid methanol-water inlet flow rates up to 1 ml/min per m2 of solar collector area can be converted to hydrogen with a methanol conversion rate above 90%.

This study will present the design and fabrication of the solar collector-reactor, its testing and optimization, and its integration into an entire hydrogen-fed Polymer Electrolyte Membrane fuel cell system.
Flame-Made CuO/ZnO/Al2O3 Catalyst for Methanol Steam Reforming
Authors: Lim Emmanuel , Visutipol Teeravit , Peng Wen , Hotz Nico
Published: December 2013

In the present study, a catalyst produced by flame spray pyrolysis (FSP) was evaluated for its ability to produce hydrogen-rich gas mixtures. Catalyst particles fabricated by a novel flame spray pyrolysis method resulting in a highly active catalyst with high surface-to-volume ratio were compared to a commercially produced catalyst (BASF F3-01). Both catalysts consisted of CuO/ZnO/Al2O3 of identical composition (CuO 40wt%, ZnO 40wt%, Al2O3 20wt%). Reaction temperatures between 220 and 295 °C, methanol-water inlet flow rates between 2 and 50 μl/min, and reactor masses between 25 and 100 mg were tested for their effect on methanol conversion and the production of undesired carbon monoxide. 100% methanol conversion can be easily achieved within the operational conditions mentioned for this flame-made catalyst — at reactor temperatures of 255 °C (achievable with non-concentrating solar collectors) more than 80% methanol conversion can be reached for methanol-water inlet flow rates as high as 10 μl/min. The FSP catalyst demonstrates similar catalytic abilities as the BASF, produces a consistent gas composition and produces lower overall CO production. Furthermore, the FSP catalyst demonstrates a better suitability to fuel cell use through its higher resistance to degradation and smaller production of carbon monoxide over long-term use.

In the present study, the merits of using flame spray pyrolysis to produce CuO/ZnO/Al2O3 methanol steam reforming catalysts are examined, and directly compared to catalysts that are commercially produced in bulk pellet form, and then ground and sieved. The comparison is performed from several different perspectives: catalytic activity and CO production at various temperatures and fuel inlet flow rates; surface and structure characteristics are determined via scanning electron and transmission electron microscopy; surface area characteristics are determined via BET tests.
Experimental Investigation of Advanced Microscale Reactors for Enhanced Carbon Capture and Natural Gas Sweetening Applications
Authors: Ganapathy Harish , Shooshtari Amir , Dessiatoun Serguei , Alshehhi Mohamed , Ohadi Michael M.
Published: December 2013

There is an active need to develop compact mass transfer systems for high efficiency gas-liquid absorption applications, such as solvent-based carbon capture and natural gas sweetening processes. The present paper focuses on the absorption of carbon dioxide in aqueous diethanolamine using microreactors having hydraulic diameters of 762, 508 and 254 μm. The mass transfer phenomenon was studied and characterized with respect to absorption efficiency and mass transfer coefficient. Parametric studies were conducted varying the liquid and gas phase concentrations. Liquid-side volumetric mass transfer coefficients as high as 620 s−1 were achieved, which is between 2–3 orders of magnitude higher than that reported for most conventional gas-liquid absorption systems. High levels of absorption efficiency, close to 100%, were observed under certain operating conditions. The presently observed process intensification was attributed to an increase in the specific interfacial area with reduction in the channel diameter.
Design and Experimental Investigation of a Heat Pipe Supported External Cooling System for HT-PEFC Fuel Cell Stacks
Authors: Supra Jen , Janßen Holger , Lehnert Werner , Stolten Detlef
Published: December 2013

A 10-cells HT-PEFC stack with an active cell area of 200 cm2 has been built up and tested regarding the temperature distribution from cell to cell and over the active area since not every cell is cooled. Measurements with artificial reformate as a fuel show that the vertical temperature distribution over the active area is sufficiently small, with a maximum of 5.1 K at 550 mA cm−2. Also the temperature gradient from cell to cell is sufficiently small with 10.7 K at 550 mA cm−2. As a result it can be mentioned, that the heat pipe supported external cooling is well suited to cool HT-PEFC stacks with large active areas in reformate operation.
Neutron Imaging of Water Accumulation in the Active Area and Channel-to-Manifold Transitions of a PEMFC
Authors: Liu Xuan , Trabold Thomas A. , Gagliardo Jeffrey J. , Jacobson David L. , Hussey Daniel S.
Published: December 2013

Management of liquid water formed by the electrochemical fuel cell reaction is a key factor in PEMFC performance and durability. For practical stack applications, an important consideration is the transport of liquid water at the transition between the ends of the bipolar plate channels and the manifolds, where excess reactant flows from all the individual cells are combined and directed to the stack exhaust. In this region, gas-phase momentum can be very low, especially on the anode, where there is little driving force to remove liquid water that may accumulate as a result of geometrical or surface energy variations, or due to relatively low temperatures that exist outside of the fuel cell active area. This study seeks to characterize the water accumulated within the active area and at the channel-to-manifold transition regions at both the anode and cathode outlets, as a function of cell operating temperature and current density. The neutron imaging method was applied to directly measure the water volumes within the transition regions, and provide a comparison to simultaneously measured water volume within the cell active area. Transition-region water was found to be weakly dependent on current density, suggesting that once water forms in this area, little driving force exists to extract it entirely by means of gas momentum. Moreover, it was found that the active area water volume is strongly dependent on cell temperature, and temperature variation of as little as 0.5 °C can produce a significant change in water accumulation which is reflected in the cell voltage.
PEMFC Stack Activation Through Thermal Management
Authors: Bethapudi Sasank Viswanath , Rajalakshmi N. , Dhathathreyan K. S.
Published: December 2013

Activation of PEM fuel cell stack is an important factor in setting peak power of stack before its steady operations. Several methods of activation for larger capacity stacks involve operation of the stacks initially at low voltages under highly humidified conditions and at high temperatures. This is expected to improve proton conductivity of the membrane. For large area cells this method can create hot spots due to high current and non-uniform temperature distribution. Hence, an alternative approach for activating PEMFC stack at low current for vehicular applications has been investigated in this study. Conventional stack activation requires continuous supply of coolant. However for vehicular applications, a closed loop thermal management system is required. During the course of developing such a close loop thermal management system for transportation application, we have identified that the same system can be used in activating a PEM fuel cell stack. In the present study a 5kW PEMFC stack, operating on dry reactants, has been activated using a closed loop thermal management system. The activation has been carried out over a period of 620 minutes with 6 start/stop cycles. Through the start stop cycles the power delivered by the stack steadily increased from 2.5kW, to 5kW. Further, heat developed inside the fuel cell, as removed by the coolant water, has been studied and there is a proportional increase in the overall heat removed by the coolant to the total power delivered by the fuel cell. The start stop cycles are regulated based on the single cell voltages and stack temperature. Each cycle is stopped when the stack temperature reaches a set temperature of 50°C. The advantage of this procedure is that it will result in long life of the fuel cell stack, uniform membrane equilibration, and will avert hot spot generation in the electrodes at low cell potential.
Coexistence of 3G Repeaters with LTE Base Stations
Authors: Yeo Woon-Young , Lee Sang-Min , Hwang Gyung-Ho , Kim Jae-Hoon
Published: December 2013

Repeaters have been an attractive solution for mobile operators to upgrade their wireless networks at low cost and to extend
network coverage effectively. Since the first LTE commercial deployment in 2009, many mobile operators have launched LTE
networks by upgrading their 3G and legacy networks. Because all 3G frequency bands are shared with the frequency bands
for LTE deployment and 3G mobile operators have an enormous number of repeaters, reusing 3G repeaters in LTE networks is
definitely a practical and cost‐efficient solution. However, 3G repeaters usually do not support spatial multiplexing with multiple
antennas, and thus it is difficult to reuse them directly in LTE networks. In order to support spatial multiplexing of LTE, the role
of 3G repeaters should be replaced with small LTE base stations or MIMO‐capable repeaters. In this paper, a repeater network
is proposed to reuse 3G repeaters in LTE deployment while still supporting multilayer transmission of LTE. Interestingly, the
proposed network has a higher cluster throughput than an LTE network with MIMO‐capable repeaters.
The Accuracy of Prostate Cancer Localization Diagnosed on Transrectal Ultrasound-Guided Biopsy Compared to 3-Dimensional Transperineal Approach
Authors: Krughoff Kevin , Eid Khadijah , Phillips Jason , Stoimenova Diliana , Smith Daniel , O’Donnell Colin , Crawford E. David , Barqawi Al
Published: December 2013

Background. Prostate cancer is often understaged following 12-core transrectal ultrasound- (TRUS-) guided biopsies. Our goal is to understand where cancers are typically missed by this method.Methods. Transperineal 3-dimensional mapping biopsy (3DMB) provides a more accurate depiction of disease status than transrectal ultrasound- (TRUS-) guided biopsy. We compared 3DMB findings in men with prior TRUS-guided biopsies to determine grade and location of missed cancer. Results were evaluated for 161 men with low-risk organ confined prostate cancer.Results. The number of cancer-positive biopsy zones per patient with TRUS was 1.38 ± 1.21 compared to 3.33 ± 4.06 with 3DMB, with most newly discovered cancers originating from the middle lobe and apex. Approximately half of all newly discovered cancerous zones resulted from anterior 3DMB sampling. Gleason upgrade was recognized in 56 patients using 3DMB. When both biopsy methods found positive cores in a given zone, Gleason upgrades occurred most frequently in the middle left and right zones. TRUS cancer-positive zones not confirmed by 3DMB were most often the basal zones.Conclusion. Most cancer upgrades and cancers missed from TRUS biopsy originated in the middle left zone of the prostate, specifically in anterior regions. Anterior sampling may lead to more accurate diagnosis and appropriate followup.
Electronic Properties of Boron and Silicon Doped (10, 0) Zigzag Single‐Walled Carbon Nanotube upon Gas Molecular Adsorption: A DFT Comparative Study
Authors: Gowri sankar P. A. , Udhayakumar K.
Published: December 2013

We have performed a comparative study of nine predominant gas molecules (H2, H2O, O2, CO, CO2, NO, NO2, NH3, and CH3OH) adsorption property on the top surface of the (10, 0) zigzag single‐walled pristine Carbon nanotube (C‐CNT), Boron doped carbon nanotube (B‐CNT), and Silicon doped carbon nanotube (Si‐CNT) are investigated by using density functional theory (DFT) computations to exploit their potential applications as gas sensors. For the first time, we calculated the optimal equilibrium position, absorption energy (Ead), and density of states (DOS) of the considered gas molecules adsorbed on the open end of zigzag single‐walled (10, 0) B‐CNT and Si‐CNT. Our first principle calculations demonstrate that the B‐CNT and Si‐CNT adsorbent materials are able to adsorb the considered gas molecules with variety of adsorption energy and their electronic structure dramatic changes in the density of states near the Fermi level. The obtained comparative DFT studies results are useful for designing a high‐fidelity gas sensor materials and selective adsorbents for a selective gas sensor.
S100β Levels in CSF of Nonambulatory Dogs with Intervertebral Disk Disease Treated with Electroacupuncture
Authors: Murata Hayashi Ayne , Fonseca Pinto Ana Carolina Brandão Campos , Cortopassi Silvia Renata Gaido , Marvulle Valdecir , Ruivo Maximino Jessica , Chadi Gerson , Matera Julia Maria
Published: December 2013

The aim of the study was to investigate S100β levels in the cerebrospinal fluid of nonambulatory dogs with intervertebral disk disease treated with electroacupuncture:
10 dogs with thoracolumbar disk extrusion graded 3 to 5 (EA group) and 7 dogs without neurologic dysfunction (control group). All dogs regained ambulation. S100β was detected by Western blot analysis where EA group dogs were evaluated at two time points (M1 = before EA and M2 = when the dogs return ambulation) and at one time point from control group. In EA group dogs M1-S100β levels were significantly higher than in control group. EA group dogs were divided into subgroups A (n=7—early motor recovery; 6.7±7.8 days) and B (n=3—late motor recovery; 76±17.0 days). M1-S100β levels were similar between subgroups A and B. However, M2-S100β levels were significantly higher in subgroup B than in subgroup A. An elevated S100β levels were observed in dogs with late motor recovery. S100β may be associated with neuroplasticity following spinal cord injuries with intervertebral disk extrusion. Further studies with larger numbers of subjects and control group with affected dogs are necessary to investigate the relationship between neurotrophic factors and electroacupuncture stimulation.
Dubhe: A Reliable and Low-Latency Data Dissemination Mechanism for VANETs
Authors: Zhang Lifeng , Jin Beihong
Published: December 2013

Many attractive applications over vehicular ad hoc networks (VANETs) need data to be transmitted to the remote destinations through multihop data forwarding, but some unique characteristics of VANETs (i.e., high node mobility, dynamic topology changes with frequent link breakage, and unstable quality of wireless transmission) incur unstable data delivery performance. In order to reliably and quickly disseminate the data, we present Dubhe which includes a delay model and an improved greedy broadcast algorithm embedded with a coverage elimination rule. The former is used for making decisions for path selection with the aim of minimizing the transmission latency, while the latter focuses on boosting the reliability of one-hop data transmission. We also analyze the necessity and effectiveness of Dubhe and the retransmission overheads theoretically. It is shown from the experiments that Dubhe can achieve high-reliability and low-latency data delivery in comparison with the epidemic-based protocol and the static-node-assisted adaptive data delivery protocol.
Seroprevalence of St. Louis Encephalitis Virus and West Nile Virus (Flavivirus,Flaviviridae) in Horses, Uruguay
Authors: Burgueño Analía , Spinsanti Lorena , Díaz Luis Adrián , Rivarola María Elisa , Arbiza Juan , Contigiani Marta , Delfraro Adriana
Published: December 2013

St. Louis encephalitis virus (SLEV) and West Nile virus (WNV) belong to the Japanese encephalitis antigenic complex (Flavivirusgenus,Flaviviridaefamily). They show antigenic close relationships and share many similarities in their ecology. Both are responsible for serious human diseases. The aim of this study was to investigate the presence of neutralizing antibodies to these viruses in horses from Uruguay. To do this, 425 horse sera were collected in 2007 and analyzed by plaque reduction neutralization tests. As a result, 205 sera (48.2%) were found positive for SLEV, with titers ranging between 10 and 80. Two sera remained inconclusive, since they showed low titers to WNV and SLEV (10 and 20), not allowing us to demonstrate activity of WNV in our territory. This is the first report of circulation of SLEV in horses in Uruguay.
Inhibition of Nuclear Nox4 Activity by Plumbagin: Effect on Proliferative Capacity in Human Amniotic Stem Cells
Authors: Guida Marianna , Maraldi Tullia , Resca Elisa , Beretti Francesca , Zavatti Manuela , Bertoni Laura , La Sala Giovanni B. , De Pol Anto
Published: December 2013

Human amniotic fluid stem cells (AFSC) with multilineage differentiation potential are novel source for cell therapy. However,in vitroexpansion leads to senescence affecting differentiation and proliferative capacities. Reactive oxygen species (ROS) have been involved in the regulation of stem cell pluripotency, proliferation, and differentiation. Redox-regulated signal transduction is coordinated by spatially controlled production of ROS within subcellular compartments. NAD(P)H oxidase family, in particular Nox4, has been known to produce ROS in the nucleus; however, the mechanisms and the meaning of this function remain largely unknown. In the present study, we show that Nox4 nuclear expression (nNox4) increases during culture passages up to cell cycle arrest and the serum starvation causes the same effect. With the decrease of Nox4 activity, obtained with plumbagin, a decline of nuclear ROS production and of DNA damage occurs. Moreover, plumbagin exposure reduces the binding between nNox4 and nucleoskeleton components, as Matrin 3. The same effect was observed also for the binding with phospho-ERK, although nuclear ERK and P-ERK are unchanged. Taken together, we suggest that nNox4 regulation may have important pathophysiologic effects in stem cell proliferation through modulation of nuclear signaling and DNA damage.
Sphingosine-1-phosphate-Mediated Mobilization of Hematopoietic Stem/Progenitor Cells during Intravascular Hemolysis Requires Attenuation of SDF-1-CXCR4 Retention Signaling in Bone Marrow
Authors: Mierzejewska Kasia , Klyachkin Yuri M. , Ratajczak Janina , Abdel-Latif Ahmed , Kucia Magda , Ratajczak Mariusz Z.
Published: December 2013

Sphingosine-1-phosphate (S1P) is a crucial chemotactic factor in peripheral blood (PB) involved in the mobilization process and egress of hematopoietic stem/progenitor cells (HSPCs) from bone marrow (BM). Since S1P is present at high levels in erythrocytes, one might assume that, by increasing the plasma S1P level, the hemolysis of red blood cells would induce mobilization of HSPCs. To test this assumption, we induced hemolysis in mice by employing phenylhydrazine (PHZ). We observed that doubling the S1P level in PB from damaged erythrocytes induced only a marginally increased level of mobilization. However, if mice were exposed to PHZ together with the CXCR4 blocking agent, AMD3100, a robust synergistic increase in the number of mobilized HSPCs occurred. We conclude that hemolysis, even if it significantly elevates the S1P level in PB, also requires attenuation of the CXCR4-SDF-1 axis-mediated retention in BM niches for HSPC mobilization to occur. Our data also further confirm that S1P is a major chemottractant present in plasma and chemoattracts HSPCs into PB under steady-state conditions. However, to egress from BM, HSPCs first have to be released from BM niches by blocking the SDF-1-CXCR4 retention signal.
Experimental Investigation on Material Transfer Mechanism in WEDM of Pure Titanium (Grade-2)
Authors: Kumar Anish , Kumar Vinod , Kumar Jatinder
Published: December 2013

This research work mainly focused on experimental investigation on material transfer mechanism in WEDM of pure titanium. The effects of machining parameters such as pulse on time, pulse off time, peak current, spark gap voltage, wire feed, and wire tension on the material removal rate (MRR), overcut, and surface roughness for pure titanium in WEDM process were explored. The selected machined samples were analyzed using energy dispersive X-ray analysis, scanning electron microscope, and X-ray diffraction techniques. It was observed from the results that a significant material transfer occurred from the dielectric, as well as tool, electrode on the work surface either in free form and/or in compound form. Also the multiresponse optimization of process parameters was done using desirability approach. The predictions from this model were validated by conducting experiments.
Surfactant Modified/Mediated Thin-Layer Chromatographic Systems for the Analysis of Amino Acids
Authors: Bhawani Showkat A. , Albishri Hassan M. , Khan Ziya Ahmad , Mohamad Ibrahim Mohamad N. , Mohammad A.
Published: December 2013

This review incorporates a large number of chromatographic systems modified by the surfactants. A large number of solvent systems and stationary phases are summarized in this paper. Three different kinds of surfactants (anionic, cationic, and nonionic) are used as modifiers for stationary phases as well as solvent systems. Surfactants are used at all the three different concentration levels (below, above, and at critical micelle concentration) where surfactants behave differently. Modifications of both stationary phases and solvent systems by surfactants produced a new generation of chromatographic systems. Microemulsion solvent systems are also incorporated in this paper. Microemulsion thin-layer chromatography is a new approach in the field of chromatography.
Neuroprotective Activity of Thioctic Acid in Central Nervous System Lesions Consequent to Peripheral Nerve Injury
Authors: Tomassoni Daniele , Amenta Francesco , Di Cesare Mannelli Lorenzo , Ghelardini Carla , Nwankwo Innocent E. , Pacini Alessandra , Tayebati Seyed Khosrow
Published: December 2013

Peripheral neuropathies are heterogeneous disorders presenting often with hyperalgesia and allodynia. This study has assessed if chronic constriction injury (CCI) of sciatic nerve is accompanied by increased oxidative stress and central nervous system (CNS) changes and if these changes are sensitive to treatment with thioctic acid. Thioctic acid is a naturally occurring antioxidant existing in two optical isomers (+)- and (−)-thioctic acid and in the racemic form. It has been proposed for treating disorders associated with increased oxidative stress. Sciatic nerve CCI was made in spontaneously hypertensive rats (SHRs) and in normotensive reference cohorts. Rats were untreated or treated intraperitoneally for 14 days with (+/−)-, (+)-, or (−)-thioctic acid. Oxidative stress, astrogliosis, myelin sheets status, and neuronal injury in motor and sensory cerebrocortical areas were assessed. Increase of oxidative stress markers, astrogliosis, and neuronal damage accompanied by a decreased expression of neurofilament were observed in SHR. This phenomenon was more pronounced after CCI. Thioctic acid countered astrogliosis and neuronal damage, (+)-thioctic acid being more active than (+/−)- or (−)-enantiomers. These findings suggest a neuroprotective activity of thioctic acid on CNS lesions consequent to CCI and that the compound may represent a therapeutic option for entrapment neuropathies.