bluuebunny/crossref_metadata_2025 huggingface dataset:
Techno-Economic Analysis of Dual-Stage Sodium Thermal Electrochemical Converter (Na-TEC) Power Block for Distributed CSP
Authors: Gunawan Andrey , Limia Alexander , Ha Jong Min , Kottke Peter A. , Lee Seung Woo , Fedorov Andrei G. , Yee Shannon K.
Published: October 2018

A sodium thermal electrochemical converter (Na-TEC) converts heat directly into electricity without moving parts by isothermal expansion of ions through beta”-alumina solid-electrolyte (BASE). These generators are most similar to thermoelectric generators; however, they are considerably more efficient than the best performing thermoelectric materials. While these heat engines have been considered for CSP applications, literature review found that the efficiency of single-stage Na-TEC could readily achieve 20% even though ideal cycle efficiencies predict above 45% efficiency at elevated temperatures. Thermal parasitic loss has been identified to be responsible for the largest drop in the efficiency. Our recent study shows that staging helps to improve thermal management of the Na-TEC, due to the lower average temperature of the device, which can reduce the thermal parasitic loss. We demonstrate that dual-stage device can improve the efficiency by up to 8% over the best performing single-stage device. We are currently designing and developing a modular dual-stage Na-TEC power block with target efficiency of 33%. We emphasize modularity because this power block can be potentially deployed for both small-scale dish solar, which is appropriate for distributed residential scale (2–3 kWe), and large-scale heliostats and parabolic trough CSP, which is appropriate for centralized industrial scale. A fundamental cost-scaling relationship for this technology was developed based on this design. System variables and component manufacturing methods with material selection for processes were established. The current off-the-shelf component costs indicated an overnight capital cost of $2,044/kWe. The costs of BASE, manufacturing, and electrode preparation have driven the overall price of the module. The paper demonstrates $/W design optimization and cost scaling analysis to reduce the system capital $/W metric below $ 1,500/kWe, with the goal being to achieve the cost target of <900/kWe set by Department of Energy’s Sun Shot Initiative.
A Comparative Study of Industrial Energy Assessments for Small and Medium-Sized Industrial Facilities
Authors: Abbas Ahmad I. , Saravani Mandana S. , Al-Haddad Muhannad R. , Amano Ryoichi S. , Qandil Mohammad Darwish
Published: October 2018

The Industrial Assessment Center at University of Wisconsin-Milwaukee (WM-IAC) has implemented over 100 industrial energy, waste, and productivity assessments, and has recommended $9.5 million of energy and operational savings with about 950 recommendations since it was re-established in 2011. This paper analyzes the assessments, and the recommendations were performed over two years only, 2014 and 2015. During these two years, a total of 40 assessments were created by visiting different manufacturing facilities with the analysis of the data gathered and processed. The determinants of the data were the number of recommendations, recommended energy savings (in kWh/year), recommended energy cost savings (in US$/year), implemented energy savings (in US$/year), the Standard Industrial Code (SIC) and the groups of Energy Efficiency Opportunities (EEOs). Such an analytical study was meant to reveal the significance of EEO groups through a variety of SICs in terms of the potential for energy savings, particularly focused towards choosing plant facilities for IAC assessments. Additionally, this paper could be considered as a guide for plant managers, energy engineers and other personnel involved in the energy assessment process. Conclusions are inferred with respect to the most promising EEOs that can be resolved based on the characteristics of the manufacturing plants visited. The information investigated can pave the way for composing energy demanding industries and expose priority goal areas regarding minimizing the energy consumption.
Analysis of Loss-of-Flow Accidents in Pre-Cooler and Inter-Cooler of HTR-10GT
Authors: Yang Xiaoyong , Li Xiao , Wang Jie , Zhang Youjie
Published: October 2018

Closed Brayton cycle (CBC) coupled with High Temperature Gas-cooled Reactor (HTGR) has potential application due to its compact configuration, high power generation efficiency and inherent safety. It is also one of the major power conversion methods for Generation IV advanced nuclear power systems. The typical CBC has several helium-water heat exchangers, including pre-cooler and inter-cooler. These helium-water heat exchangers have important influence on the performance of power conversion system, especially in loss-of-flow accidents (LOFAs). A system model including the reactor and the energy conversion system was established in this paper. The 10MW High Temperature Gas-cooled reactor-test Module helium Gas Turbine (HTR-10GT) was taken as the example to show the consequences of LOFAs. The results showed that LOFAs led to the rising of water temperature out of heat exchangers. With the reduction of water flow rate, the maximum water temperature would increase sharply, and the water temperature in pre-cooler was higher than that in inter-cooler. At low water flow rate, the water temperature would exceed the boiling point. LOFAs also made the rising of helium temperature. It had impacts on the performance of helium compressors. The elevated inlet temperature of helium compressors changed the corrected speed and corrected flow rate, therefore caused the deterioration of compressor’s performance. Furthermore, the LOFAs caused the reactor inlet temperature increasing. In low water flow rate, it would make the reactor inlet temperature beyond the temperature limitation of reactor pressure vessel and influence the safety of reactor. And the LOFAs also reduced the output work of cycle. This paper provides insights of features of CBC in LOFAs and will be helpful to the design and safety operation of closed Brayton cycle coupled with HTGR.
Guidelines for the Design, Installation, Operation and Maintenance of Safety Relief Devices for Steam Surface Condensers
Authors: Nightingale Darren M.
Published: October 2018

Steam surface condensers may require several different relief devices for safe operation. Atmospheric relief devices are typically utilized for the safe relief of over-pressure on the shell-side (LP steam). This is to protect and prevent steam surface condensers, often including steam turbine exhaust hoods, from exceeding specified design pressures. In addition to shell-side safety devices, relief devices for the tube-side (cooling water), such as water box pressure & vacuum relief, venting and air removal valves, all perform a similar function.

This paper provides a thorough background to all the types of condenser safety relief devices currently available. The latest applicable standards, codes and guidelines for these safety relief devices are reviewed, in conjunction with the current methodology for the correct design and sizing of such devices. Several sample calculations and working examples for the correct sizing of safety devices are provided for reference. The paper includes a review of the relative attributes and considerations for the appropriate selection of each of these types of safety devices, e.g. rupture discs versus atmospheric relief valves for shell-side protection. The paper concludes with a comprehensive review of the latest guidelines for the installation, operation, and maintenance for these safety devices, including guidance on other aspects such as preferred locations, exhaust & vent piping, routine inspection, and testing requirements.
Experimental Study on the Speed Matching of Two Rotors for a Counter-Rotating Fan
Authors: Ai Zijian , Qin Guoliang , Lin Jingxiang , Chen Xuefei
Published: October 2018

A method for the speed matching of the second rotor (R2) with equal power for two rotors was proposed to avoid the overload of the second motor under low flow rate and the rapid decrease in pressure-rise and efficiency of R2 under high flow rate. The speed matching of two-stage rotors is proposed and analyzed to improve the stability margin of the counter-rotating fan (CRF). The fan performances during constant speed operating and during the speed matching operating are presented and discussed using experimental research. The results show that, the speed matching of R2 operating decreases the load of R2 under low flow rate and increases the pressure-rise and efficiency of R2 under high flow rate. Thus, the efficient working range and the blocking condition margin are increased. Reducing n1 and increasing n2 under low flow rate can regulate the position of unstable working line leftward without reducing the pressure-rise of the fan. Thus, the stability margin of the CRF is expanded.
The Influence of Vaned Diffuser Outlet Diameters on Operating Performance of a Single-Stage Centrifugal Pump
Authors: Zhu Xiangyuan , Lai Fen , Zhu Liping , Li Guojun
Published: October 2018

To enhance the efficiency and stable operation, the unsteady pressure fluctuations in a centrifugal pump and the radial force on an impeller are investigated for three different vaned diffuser outlet diameters. The steady-state hydrodynamic performance of the centrifugal pump with three different vaned diffuser outlet diameters was experimentally measured. Numerical simulations were used to obtain the hydrodynamic performance of the experimental centrifugal pump based on the Reynolds-averaged Navier-Stokes (RANS) and turbulence models. The numerical results of the hydrodynamic performance were in agreement with the experimental data. The accuracy of the utilized numerical approach was demonstrated. The unsteady flow characteristics of the centrifugal pump were numerically studied. With increasing diffuser vane outlet diameter, the flow field within the volute became more non-uniform, and the pressure fluctuation was more drastic. Moreover, because of the influence of the non-uniform flow field and the pressure fluctuation, the radial force on the impeller increased.
Syngas Production and Combustion Turbine Operation With Hydrogen-Rich Fuel at the Kemper County IGCC
Authors: Nelson Matt , Vimalchand Pannalal , Peng WanWang , Lieuwen Tim , Madden Diane Revay , Miller Paul , Pinkston Tim , Wilson Steve
Published: October 2018

The Kemper County Project has demonstrated Transport Integrated Gasification (TRIG™) at a 2-on-1 Integrated Gasification Combined-Cycle (IGCC) facility located in Kemper County, Mississippi. Kemper is the largest IGCC project in the world, the first to use lignite as fuel, the first to capture and sell CO2, and the first to produce multiple byproducts from initial startup. The facility features two Siemens SGT6-5000F gas turbines, each capable of operating on a high-hydrogen syngas produced in the Transport Gasifiers from locally mined lignite.

Using high-hydrogen syngas requires unique modifications to the combustion turbine design. Flame-diffusion combustors, rather than dry low-NOX designs, prevent flashback caused by the high hydrogen content of the syngas. Also, ports added to the turbine compressor casing allow air to be extracted from the compressor and used elsewhere in the plant, supplying up to one half of the air required by the gasifier.

The Kemper facility has achieved the integrated operation of both gasifiers, including the production of electricity from syngas by both combustion turbines. Turbine operation on the high hydrogen syngas was smooth both during normal operations and during transitions, with efficiencies meeting or exceeding expectations. This paper describes the Kemper plant design, focusing on the combustion turbine design unique to Kemper. The paper also discusses turbine design challenges specific to Kemper, provides an overview of the robust control scheme used on both syngas and natural gas co-firing operations, and provides preliminary operational and performance results, including inspection findings.
Thermo-Economic Analyses and Comparisons of Two S-CO2-Brayton-Cycle-Based Combined Power Cycles for Concentrated Solar Power Plants
Authors: Ma Yuegeng , Zhang Xuwei , Liu Ming , Liu Jiping
Published: October 2018

In order to pursue superior cycle efficiency and lower power generation cost for the CSP plants, two S-CO2–Brayton–cycle–based power cycles with different utilization methods of the residual heat recover of the top S-CO2 Brayton cycle (SCBC) are investigated to seek alternatives to the stand-alone S-CO2 cycle as the power block of concentrated solar power plants. The residual heat released by the top S-CO2 cycle are either utilized to drive a LiBr absorption chiller (AC) for further chilling of the CO2 fluids exiting the precooler before entering the main compressor inlet temperature or recovered by an organic rankine cycle (ORC) for generating electricity. Thermo-economic analysis and optimization are performed for the SCBC–AC and SCBC–ORC, respectively. The results show that the thermal and exergetic efficiencies of the SCBC–AC are comparable with those of the SCBC–ORC in low pressure ratio conditions (PR<2.7) but are apparently lower than SCBC–ORC when PR is over 2.7. The LCOE of the CSP plant integrated with SCBC–AC is more sensitive to the change of PR. The optimal PR to maximum the cycle efficiency or minimize the plant LCOE for the SCBC–ORC is higher than that for the SCBC–AC, while the optimal recuperator effectiveness to minimize the LCOE of CSP plant integrated with SCBC–ORC is lower than that of SCBC–AC. The optimization results show that the thermo-economic performance of the SCBC–AC is comparable to that of the SCBC–ORC. Significant ηex improvement and LCOE reduction can be obtained by both the two combined cycles relative to the stand-alone S-CO2 cycle. The maximal ηex improvements obtained by the SCBC–ORC and SCBC–AC are 6.83% and 4.12%, respectively. The maximal LCOE reduction obtained by the SCBC-ORC and SCBC–AC are 0.70 ȼ / (kW·h) and 0.60 ȼ / (kW·h), respectively.
Co-Combustion Characteristics of Semi-Coke and Coal Under Air Condition
Authors: Wang Pengqian , Wang Chang'an , Tao Zichen , Yuan Maobo , Du Yongbo , Zhang Jinping , Che Defu
Published: October 2018

In this work, the combustion characteristics of semi-coke, coal, and their blends under air conditions were studied. The influence of blending ratio on the combustion characteristics of blended fuels were investigated by thermogravimetric analysis. It was found that the co-combustion of semi-coke and bituminous coal was a complicated process rather than a simple linear superposition, with interaction effect occurring in the co-combustion process. The synergy occurred in the whole combustion process and it was analyzed quantitatively by comparing the interaction coefficient f and the relative root mean square error RMS. The combustion of semi-coke and the blends can be divided to three stages, as well as two stages of coal. In addition, the blends show better combustion behavior with enhancing bituminous coal proportion, and bituminous coal can improve the combustion behavior of semi-coke.
Reduced Chemical Kinetic Models Using Alternate and Stochastic Species Elimination
Authors: Eldeeb Mazen A. , Akih-Kumgeh Benjamin
Published: October 2018

This work extends the species sensitivity method of model reduction known as Alternate Species Elimination (ASE) to a stochastic version. The new Stochastic Species Elimination (SSE) approach allows for a linear reduction in the number of species retained in the course of reduction. It improves the computational cost and offers flexibility to the user in terminating the reduction process when an acceptable model size is attained. Larger chemical kinetic models, such as the recent literature model of n-octanol, are approached with the SSE method coupled with multiple species sampling. This further allows for a faster model reduction process. These modified approaches are applied to the reduction of selected chemical kinetic models based on ignition simulations: the n-heptane model by Mehl et al. (654 species, 5258 reactions), reduced using the SSE method (293 species, 2792 reactions) and the ASE method (245 species, 2405 reactions); the iso-octane model by Mehl et al. (874 species, 7522 reactions), reduced to an SSE version (315 species, 3037 reactions) and an ASE version (306 species, 2732 reactions); and the n-octanol model by Cai et al. (1281 species, 5537 reactions), with a reduced SSE version (450 species, 2532 reactions). Resulting skeletal models are shown to adequately predict ignition delay times as well as flame propagation when compared to the predictions of the detailed models. Burning velocity predictions are well-captured even though the reduction is based on ignition delay simulations.
The Power Flow Method for Analysis and Optimization of Heat Recovery and Power Generation System
Authors: Chen Xi , Chen Qun
Published: October 2018

Performance improvement of heat recovery systems has huge potential for energy conservation but puzzles researchers due to the nonlinear coupled properties. The traditional modelling approaches focus on individual components, which introduces numerous non-independent variables and further complicates the system optimization. In this contribution, through the thermo-electric analogy method, the equivalent power flow diagram is built based on the system layout, then the corresponding governing equations are derived according to the circuitous philosophy, which reveals the overall transfer and conversion laws of heat. Then, by analyzing the pressure variations of fluids in various components, the flow resistance balance equations are established, which describes the pressure distribution in circulation loop. Moreover, through combining with the coupling relations between the temperatures and pressures of fluids, the inherent physical constraints among operating parameters are revealed by introducing few intermediate variables, which provides convenience for model computation. On this basis, through reasonably matching the mass flow rates of working fluids, the net power generation is maximized under variable working conditions. The optimization results indicate the parameters variation of flue gas significantly impacts the optimal operating state of system, while the empirical constant backpressure operation strategy apparently deviates from the optimums, and the most deviation reaches 8.2%.
Thermal Performance Study of Helically Grooved Absorber Tubes for Parabolic Trough Solar Collector
Authors: Vishwakarma Suresh , Debnath Kishore , Debnath Biplab Kumar
Published: October 2018

In this work, a computational study on four different types of helically grooved absorber tubes namely, semi-circular, rectangular, trapezoidal, and triangular has been carried out for their possible application in parabolic trough solar collector. In order to conduct the work, absorber tube of 2 m length with 19 mm inner and 25 mm outer diameter is selected. Flow velocities have been calculated by fixing the Reynolds number of the flow as 4000 i.e., turbulent flow. A constant heat flux of 818.5 W/m2 is provided at the lower surface of the absorber tube, facing the reflector. The simulation is performed using the finite volume based tool ANSYS FLUENT 17.1. The standard k-ε RNG turbulence model is used for simulation. The values of friction factors for semi-circular, rectangular, trapezoidal, and triangular absorber tube are 0.0511, 0.0889, 0.0929, and 0.0352, respectively. Nusselt numbers for these tubes are calculated as 68.91, 65.69, 72.05, and 85.49. Hence, it can be concluded from the present study that the thermal performance of the absorber tube with triangular groove is superior to the other groove types. The pressure drop for the same tube is also lowest.
Innovative Field Repair of a Drain Cooler Top Plate in a Low-Pressure Feedwater Heater
Authors: Svensson Eric , Marra Dominic , Catapano Michael
Published: October 2018

In 2014, the Turkey Point Nuclear Power Plant experienced a hole and a steam leak through the shell of the Unit 4, #3B Low Pressure (LP) Feedwater Heater (FWH) near the drains outlet nozzle. Although the location of the hole in the shell was below the centerline of the heater in the Drain Cooler (DC) Zone, a video probe inspection through the drains outlet nozzle revealed that the cause of the leak was actually a hole through the DC top plate, which then allowed the steam to penetrate into the DC zone and erode the shell. The shell was able to be repaired in 2014, however there was not enough time to try to fix the hole in the top plate at that time. During a planned refueling outage in 2017, an access window was cut into the shell and the DC boundary repaired using a custom fit plate to cover the hole and prevent further leakage of steam into the DC zone. The unusual configuration of the DC sealing plates in that area made the repair challenging, but overall the repair was successful and the FWH was able to be returned to service.

Additionally, during the maintenance outage, two leaking tubes were discovered on the periphery of the bundle near one of the Steam Inlet Nozzles. In order to determine the source of the tube failure, a video probe inspection of the shell side of the heater was conducted. It was determined that Foreign Material (FM) was the cause of the failures. By removing the steam inlet piping elbow, the Foreign Material was able to be retrieved and removed from the heater.
The Effect of Temperature on Lithium-Ion Battery Energy Efficiency With Graphite/LiFePO4 Electrodes at Different Nominal Capacities
Authors: Nazari Ashkan , Esmaeeli Roja , Hashemi Seyed Reza , Aliniagerdroudbari Haniph , Farhad Siamak
Published: October 2018

In this work, the energy efficiency of the lithium-ion batteries (LIB) with graphite anode and LiFePO4 cathode (G/LFP) at different nominal capacities and charge/discharge rates is studied through multiphysics modeling and computer simulation. After characterizing all the heat generation sources in the cell, the total heat generation in LIBs is calculated and the charge/discharge efficiency plots at different temperatures are obtained. Since G/LFP LIBs have a wide range of applications in passenger and commercial electric vehicles (EVs), the result of this study assist engineer toward more efficient battery pack design.
DC-Microgrids As a Means of Rural Development in East African Countries
Authors: Aemro Yohannes Biru , Moura Pedro , de Almeida Anibal T.
Published: October 2018

According to the World Health Organization, nearly 3 billion people burn wood, crop wastes, charcoal, coal and animal dung to meet their day to day energy needs and among these nearly 1.3 billion people do not have electricity access. More than 80% of the population suffering from energy poverty are living in rural areas of developing countries, such as in East Africa. On the other hand, the potential of renewable energy resources in East African countries is huge. However, such resources are usually intermittent and therefore the use of renewable energy sources to provide modern energy access with a good reliability level, for the remote locations with lack of energy access, is still an issue. With this regard, one of the emerging technologies to solve accessibility of energy in rural and remote areas is DC-microgrids. This paper assessed the use of off-grid systems in different developing countries and presents the results in improving energy access, especially in rural and remote locations. The results indicate that the experience of some Asian countries and Tanzania in East Africa could be a good example for other East African countries to invest in off-grid systems and address energy access problems in their rural and remote locations. On the other hand, there are challenges related to financing and lack of trained man power in East African countries.
Multi-Objective Design Optimization of Rotating Regenerative Air Preheater Using Genetic Algorithm
Authors: Wang Limin , Bu Yufan , Chen Xun , Wei Xiaoyang , Li Dechao , Che Defu
Published: October 2018

In previous references, no study has been done on the optimization of rotary regenerative air preheaters (RAPHs) used in coal-fired power plants yet. The key structure parameters of RAPH include rotor radius, fluid section angles and matrix layer heights. In this study, work on the multi-objective design optimization of an RAPH was conducted by combing the thermal hydraulic calculation program which is developed to calculate the temperature and the pressure drop and the non-dominated sorting genetic algorithm (NSGA-II). The maximum heat transfer rate and the minimum friction, namely minimum outlet gas temperature and pressure drop, are considered as the conflicting objectives in the multi-optimization. The layer heights, rotor radius, angles of fluid sections and heights of matrix layers are involved in the design variables in the optimization. The optimization includes three cases in which the rotor radius upper limits are 7 m, 8 m and 9 m respectively. Sets of the Pareto-optimal front points were obtained for the different cases. The obtained optimal air-preheaters with larger upper limit of rotor radius would have better Pareto results. The optimum rotor radius is the upper limit value for different design range of rotor radius. The air-preheaters with larger upper design limit of rotor radius would have better Pareto results. In other words, if the upper design limit of rotor radius is too small, all the Pareto points in this case could not satisfy the performance requirements of heat transfer and friction, and the only way is to increase the upper design limit of rotor radius. The ratio of each optimum fluid section angle is determined by the fluid flow rate of each section.
Optimal Controlled Variable Selection for Cyber-Physical Systems
Authors: Bankole Temitayo , Pezzini Paolo , Tucker David , Bryden Kenneth , Bhattacharyya Debangsu
Published: October 2018

The design of optimal control architectures and the optimal selection of controlled variables represents a critical task for maximizing the economic profitability of operating plants. Traditionally, controlled variables are selected based on heuristics or past experiences. For cyber-physical systems (CPS), where physical and virtual components can be integrated in the same unit to evaluate the dynamic response of innovative power cycles past experiences may not be available. Trial-and-error methods can be time-consuming and costly. Besides, the selected controlled variables may not be optimal from the economic perspective. A systematic approach to the selection of controlled variable for cyber physical systems is presented here. The method is applied to a solid oxide fuel cell (SOFC)-gas turbine (GT) CPS at the National Energy Technology Laboratory (NETL) in Morgantown, WV. The main result of this work is the synthesis of optimal controlled variable sets for a cyber physical system exhibiting trade offs between economics as well as controllolability of variables.
Experimental Study of Thermal Performance Enhancement of Molten Salt Nanomaterials
Authors: Mostafavi Amirhossein , Eruvaram Vamsi Kiran , Shin Donghyun
Published: October 2018

Concentrating solar power (CSP) plants are one of the main technologies harvesting solar energy indirectly. In CSP systems, solar radiant light is concentrated into a focal receiver, where heat transfer fluid (HTF) as the energy carrier absorbs solar radiation. Thermal energy storage (TES) is the key method to expand operational time of CSP plants. Consequently, thermo-physical properties of the HTF is an important factor in transferring thermal energy. One of the promising chemicals for this purpose is a mixture of molten salts with stable properties at elevated temperatures. However, low thermal properties of molten salts, such as specific heat capacity (cp) around 1.5 kJ/kg°C, constrain thermal performance of CSP systems. Recently, many studies have been conducted to overcome this shortcoming, by adding minute concentration of nanoparticles. In this work, the selected molten salt eutectic is a mixture of LiNO3–NaNO3 by composition of 54:46 mol. % plus dispersing Silicon Dioxide (SiO2) nanoparticles with 10nm particle size. The results from the measured specific heat capacity by modulated differential scanning calorimeter (MDSC) shows a 9% cp enhancement. Moreover, the viscosity of the mixture is measured by a rheometer and the results show that the viscosity of molten salt samples increases by 27% and this may result in increasing the pumping energy of the HTF. Consequently, overall thermal performance of the selected mixture is investigated by figure of merit (FOM) analysis. The interesting results show an enhancement of the thermal storage of this mixture disregard with the viscosity increase effect.
Planning a Solar-Powered Microgrid for Remote Rural Communities on Mountainous Terrain
Authors: Lainfiesta Maximiliano , Zhang Xuewei
Published: October 2018

Based on a real-world scenario in Central America, this work is to plan and design a solar-powered microgrid for the rural communities who have had no access to electric power due to their distance from the grid as well as the mountainous terrain. The minimum spanning tree method is used to generate the initial grid topology and the difference between the results with and without the consideration of actual terrain effects is shown. The design of solar generation and energy storage has 3 options: a centralized solar park powering all communities, each community with a solar plant, and distributed generation at household level. Using dc power flow, we develop optimization algorithm to improve the solutions and compare the designs in terms of feasibility and resilience (against power congestion) or robustness (against structural damage). Through this case, it is demonstrated that our methodology can inform and assist the planning of solar-powered microgrids for remote communities.
Thermodynamic Analysis of a Parabolic Trough Solar Collector Power Generation Plant Coupled With an Organic Rankine Cycle
Authors: Alashkar Adnan , Gadalla Mohamed
Published: October 2018

In this paper, the performance of Parabolic Trough Solar Collector (PTSC)-based power generation plant is studied. The effect of adding an Organic Rankine Cycle (ORC), and a Thermal Energy Storage (TES) system on the performance and financial metrics of the PTSC-power plant is investigated. Moreover, multiple organic working fluids for the ORC are compared in terms of the thermal and exergetic efficiencies, as well as the pumping power, and the most efficient fluid is selected. Further, the TES system is characterized by two-tank storage system with a storage period of 7 hours/24 hours. A yearly, monthly, and daily performance analyses are presented based on the Typical Meteorological Year (TMY) values for the city of Abu Dhabi, to study the improvement caused by the ORC and TES system. The simulation results show that Benzene is the most efficient organic fluid, as it showed the highest thermal and exergetic efficiency, and the lowest pumping power when compared to other organic fluids. In addition, the presence of the ORC increased the annual energy output of the power plant by 4%, while the addition of the TES increased the annual energy output by 68% and decreased the LCE by 29%. In the case where both the ORC and TES are added, the annual energy output increased by 72%, while the LCE decreases by almost 31%.
New species and new records of Microdispidae (Acari: Pygmephoroidea) from Zanzibar, Tanzania
Authors: Khaustov Alexander , Ermilov Sergey
Published: October 2018

During the study of mites, inhabiting soil and litter in Zanzibar, Tanzania, five species of microdispid mites were found. Two of them, namely Cochlodispus zanzibariensis sp. nov. and Caesarodispus africanus sp. nov., are described as new for science. The genera Cochlodispus Mahunka, 1972 and Rostrodispus Mahunka, 1969 stat. nov. are redefined. Rostrodispus brevisetus (Mahunka, 1975a) comb. nov. and Scutadispus variosetosus (Mahunka, 1075a) comb. nov. are redescribed. Pseudomicrodispus setosus (Evans, 1952) is recorded from the Afrotropical region for the first time. Cochlodispus operosus Rack and Kaliszewski, 1985 is moved from the family Microdispidae to the genus Bakerdania of the family Neopygmephoridae.
Atomic layer deposition of Al2O3 and TiO2 on MoS2 surfaces
Authors: Kropp Jaron A. , Cai Yuhang , Yao Zihan , Zhu Wenjuan , Gougousi Theodosia
Published: October 2018

In this work, the authors compare the surface coverage obtained in the initial and intermediate steps of Al2O3 and TiO2 atomic layer deposition on MoS2 surfaces prepared by either mechanical exfoliation or chemical vapor deposition (CVD). They find that the film surface coverage is highly dependent on the origin and preparation of the MoS2 starting surface. While mechanical exfoliation can be used to quickly obtain few-layer MoS2 surfaces, these surfaces exhibit significant variability in quality and cleanliness, leading to unpredictable film growth. Conversely, MoS2 grown by CVD provides a more reliable starting surface resulting in significantly improved scattering in the surface coverage. They find that, on CVD MoS2, neither Al2O3 nor TiO2 film growth strongly exhibits temperature dependence described by the Langmuir adsorption model. For both processes, films up to 6 nm thick deposited on CVD MoS2 are not fully coalesced and exhibit a large concentration of pinhole type features.
Power law viscoelasticity of a fractal colloidal gel
Authors: Aime S. , Cipelletti L. , Ramos L.
Published: October 2018

Power law rheology is of widespread occurrence in complex materials that are characterized by the presence of a very broad range of microstructural length and time scales. Although phenomenological models able to reproduce the observed rheological features exist, in general a well-established connection with the microscopic origin of this mechanical behavior is still missing. As a model system, this work focuses on a fractal colloidal gel. We thoroughly characterize the linear power law rheology of the sample and its age dependence. We show that at all sample ages and for a variety of rheological tests, the gel linear viscoelasticity is very accurately described by a fractional Maxwell (FM) model, characterized by a power law behavior. Thanks to a unique setup that couples small-angle static and dynamic light scattering to rheological measurements, we show that in the linear regime, shear induces reversible nonaffine rearrangements which might be at the origin of the power law rheology and we discuss the possible relationship between the FM model and the microscopic structure of the gel.
Trio earns physics Nobel for turning lasers into tools
Authors: Cho Adrian
Published: October 2018

Prize honors discoveries that led to optical tweezers and short, powerful bursts of laser light.
An autoimmune disease variant of IgG1 modulates B cell activation and differentiation
Authors: Chen Xiangjun , Sun Xiaolin , Yang Wei , Yang Bing , Zhao Xiaozhen , Chen Shuting , He Lili , Chen Hui , Yang Changmei , Xiao Le , Chang Zai , Guo Jianping , He Jing , Zhang Fuping , Zheng Fang , Hu Zhibin , Yang Zhiyong , Lou Jizhong , Zheng Wenjie , Qi Hai , Xu Chenqi , Zhang Hong , Shan Hongying , Zhou Xu-jie , Wang Qingwen , Shi Yi , Lai Luhua , Li Zhanguo , Liu Wanli
Published: October 2018

An IgG1 SNP enhances autoimmunity

One common feature of autoimmune diseases like systemic lupus erythematosus (SLE) is the presence of high titers of self-reactive antibodies. These result in immune complexes, inflammation, and tissue pathology. Consequently, the checkpoints that normally keep immunoglobulin G (IgG)–positive autoreactive B cells in check are of intense interest. Chen
et al.
report the presence of a common IgG1 single-nucleotide polymorphism (SNP) in East Asian populations (hIgG1-G396R). This SNP was enriched in SLE patients and associated with increased disease severity. Humans with this SNP, as well as knockin mice, showed enhanced plasma cell accumulation and antibody production. This SNP enhanced IgG1 immunoglobulin tail tyrosine motif phosphorylation, triggering longer adaptor protein Grb2 dwell times in immunological synapses and hyper–Grb2–Bruton's tyrosine kinase signaling after antigen binding.

Science
, this issue p.
700
Rapid Pliocene adaptive radiation of modern kangaroos
Authors: Couzens Aidan M. C. , Prideaux Gavin J.
Published: October 2018

Secrets revealed by kangaroo teeth

The teeth of mammals display complex adaptations to diet and can thus provide a window into the environments of extinct species. Couzens and Prideaux used such a window to examine the expansion and diversification of kangaroos, Australia's largest herbivores (see the Perspective by Polly). True kangaroos diversified not in response to drying in the Miocene, as suggested by molecular results, but rather as grasslands expanded during the Pliocene. Furthermore, the now-extinct short-faced kangaroos were not declining because of increases in aridity at the end of the Pleistocene but instead were experiencing an increase in dietary divergence.

Science
, this issue p.
72
; see also p.
25
Urbanization and humidity shape the intensity of influenza epidemics in U.S. cities
Authors: Dalziel Benjamin D. , Kissler Stephen , Gog Julia R. , Viboud Cecile , Bjørnstad Ottar N. , Metcalf C. Jessica E. , Grenfell Bryan T.
Published: October 2018

Seasonal flu by ZIP code

Influenza virus strikes communities in northern latitudes during winter, straining health care provision almost to the breaking point. Change in environmental humidity is a key driver, but many other seasonal and social factors contribute. Dalziel
et al.
obtained a geographical distribution of doctor visits for influenza-like illness for more than 600 U.S. cities (see the Perspective by Wallinga). Some ZIP codes regularly experienced sharply defined peaks of cases, or intense epidemics, and others showed a longer, more diffuse influenza season. The surges tended to occur in smaller cities with less residential density and lower household incomes. Larger, more densely populated cities had more-diffuse epidemics, presumably because of higher rates of personal contact, which makes influenza transmission less subject to climate variation.

Science
, this issue p.
75
; see also p.
29
Agricultural research, or a new bioweapon system?
Authors: Reeves R. G. , Voeneky S. , Caetano-Anollés D. , Beck F. , Boëte C.
Published: October 2018

Insect-delivered horizontal genetic alteration is concerning
Mythical androids and ancient automatons
Gods and Robots: Myths, Machines, and Ancient Dreams of Technology
Adrienne Mayor
Princeton University Press, 2018. 291 pp.
Authors: Olson Sarah
Published: October 2018

Technology tales from classical literature reveal the storied history of artificial intelligence
Marsupial responses to global aridification
Authors: Polly P. David
Published: October 2018

Tooth evolution in Australian kangaroos was a late response to climate change in the Neogene
Tamm-Horsfall Protein Protects the Urinary Tract against
Candida albicans
Authors: Coady Alison , Ramos Anissa R. , Olson Joshua , Nizet Victor , Patras Kathryn A.
Published: October 2018

Urinary tract infections (UTIs) caused by the human fungal pathogen
Candida albicans
and related species are prevalent in hospitalized patients, especially those on antibiotic therapy, with indwelling catheters, or with predisposing conditions such as diabetes or immunodeficiency. Understanding of key host defenses against
Candida
UTI is critical for developing effective treatment strategies.
Amino Acid Residue 217 in the Hemagglutinin Glycoprotein Is a Key Mediator of Avian Influenza H7N9 Virus Antigenicity
Authors: Chang Pengxiang , Sealy Joshua E. , Sadeyen Jean-Remy , Iqbal Munir
Published: October 2018

Avian influenza H7N9 viruses circulating in poultry and wild birds continue to evolve and acquire important phenotypic changes. Mutations to the virus hemagglutinin (HA) glycoprotein can modulate virus antigenicity and facilitate virus escape from natural or vaccine-induced immunity. The focus of this study was to identify evolutionary markers in the HA of H7N9 that drive escape from antibody-based immunity. To achieve this, we propagated low-pathogenicity H7N9 virus in the presence of polyclonal antiserum derived from ferrets infected with the same strain of virus (homologous antiserum). This selection process was repeated 10 times. The HA gene sequences of viruses recovered after the fifth passage showed that the viruses readily acquired mutations at three different amino acid positions (A125T, A151T, and L217Q). Further functional analysis of these mutations confirmed that the mutation at residue 217 in the HA was responsible for mediating changes to the immunological properties of the H7N9 virus.
Borderline Mucinous Testicular Tumour: Diagnostic and Management difficulties
Authors: Pratap Krishan , Perera Marlon , Malczewski Frances , Esler Rachel
Published: October 2018

A 45-year-old man presented with right-sided testicular swelling and pain. An examination found a tender, firm right testis, a clinically normal left testis and no palpable lymphadenopathy. Tumour and inflammatory markers were within normal limits. A scrotal ultrasound scan showed an intratesticular, avascular lesion measuring 4.4×2.6×1.8 cm. A CT scan of his chest/abdomen/pelvis (CT C/A/P) showed no metastatic or primary lesions. An elective right-inguinal orchidectomy was subsequently performed. Histopathology showed a cystic mucinous tumour lined with intestinal-type epithelium. Differentials of metastatic adenocarcinoma, possibly of a gastrointestinal origin, a monodermal teratoma, or a borderline mucinous tumour of the testicle (BMTT) were considered. Following 12 p genetic studies and a colonoscopy, both of which found no abnormalities, a presumptive diagnosis of a BMTT was made. The patient is to have an annual urological review with a CT C/A/P and 5 yearly colonoscopies.
Pericardial effusion as first presentation of disseminated non-Hodgkin’s lymphoma
Authors: Giudicatti Lauren Christina , Cirillo Melita , King Benjamin
Published: October 2018

A 46-year-old woman with quiescent lupus presented with worsening pleuritic chest pain and dyspnoea. Bedside echocardiogram confirmed large pericardial effusion with cardiac tamponade. Emergency bedside pericardiocentesis was performed. Pericardial fluid cytology confirmed diffuse large B cell lymphoma, stage four on positron emission tomography. Conventional rituximab, cyclophosphamide, doxorubicin, vincristine and prednisolone chemotherapy achieved good response in all sites except the pericardium. Progressive cardiac involvement was complicated by atrioventricular conduction block requiring permanent pacemaker. Second-line palliative chemotherapy was performed.
Preventive effect of oral magnesium in postmastectomy pain: protocol for a randomised, double-blind, controlled clinical trial
Authors: Morel Véronique , Joly Dominique , Villatte Christine , Pereira Bruno , Pickering Gisèle
Published: October 2018

Introduction

Breast cancer affects 1 in 10 women worldwide, and mastectomy is a cause of chronic pain with neuropathic characteristics.N-methyl-D-aspartate receptor (NMDAR) antagonists such as ketamine, memantine, dextromethorphan or magnesium are used to treat refractory pain by blocking NMDAR. Oral memantine has been shown to prevent postmastectomy pain and cognitive impact and to maintain quality of life. Likewise, the present study is intended to assess the preventive effect of oral magnesium, administered ahead of mastectomy, on the development of neuropathic pain. As a physiological blocker of NMDAR, magnesium could be an interesting candidate to prevent postoperative pain and associated comorbidities, including cognitive and emotional disorders, multiple analgesic consumption and impaired quality of life.

Methods and analysis

A randomised double-blind controlled clinical trial (NCT03063931) will include 100 women with breast cancer undergoing mastectomy at the Oncology Hospital, Clermont-Ferrand, France. Magnesium (100 mg/day; n=50) or placebo (n=50) will be administered for 6 weeks, starting 2 weeks before surgery. Intensity of pain, cognitive and emotional function and quality of life will be assessed by questionnaires. The primary endpoint is pain intensity on a 0–10 numerical rating scale at 1 month postmastectomy. Data analysis will use mixed models; all tests will be two-tailed, with type-I error set at α=0.05.

Ethics and dissemination

The study protocol and informed consent form were approved in December 2016 by the French Research Ethics Committee (South East VI Committee). Results will be communicated in various congresses and published in international publications.

Trial registration number

NCT03063931.
Protocol for a prospective multicentre registry cohort study on suicide attempters given the assertive case management intervention after admission to an emergency department in Japan: post-ACTION-J Study (PACS)
Authors: Kawanishi Chiaki , Ishii Takao , Yonemoto Naohiro , Yamada Mitsuhiko , Tachikawa Hirokazu , Kishimoto Toshifumi , Tsujii Noa , Hashimoto Satoshi , Kinoshita Toshihiko , Mimura Masaru , Okubo Yoshiro , Otsuka Kotaro , Yoshimura Reiji
Published: October 2018

Introduction

Suicide attempt is the most important risk factor for later suicide. A randomised-controlled, multicentre trial of postsuicide attempt case management for the prevention of further suicide attempts in Japan, named ACTION-J, has established effective interventions for prevention of suicide reattempts. The ACTION-J assertive case management intervention programme was adopted by the Japanese Ministry of Health, Labour and Welfare in 2016, when medical fees were revised. This nationwide programme is provided to patients who attempt suicide and who are admitted to emergency departments in Japan.

The aim of the present study is to examine the current implementation status of the ACTION-J programme. The present study also aims to clarify which patients’ and hospitals’ factors affect the implementation of the programme.

Methods and analysis

This is a prospective, multicentre, patient registry cohort study. Participants will be suicide attempters admitted to the emergency departments of medical facilities with both psychiatry and emergency departments. The assertive case management programme will be delivered to participants by a case manager for up to 24 weeks, based on psychiatric diagnoses, social risks and patient needs. The core feature of the programme is to encourage patients to participate in psychiatric treatment.

The primary outcome will be the proportion of patients still participating in the case management intervention at 24 weeks after registration. The secondary outcomes will include measures of the fidelity of the case management intervention. The fidelity will be evaluated using a fidelity assessment manual developed by the study group.

Ethics and dissemination

This observational study has been approved by the ethics board of Sapporo Medical University. Enrolment began in October 2016 and will continue until December 2018. Dissemination plans include presentations at scientific conferences and scientific publications.

Trial registration

UMIN000024474.