bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effects of soft cryotherapy on conjunctiva and cornea in isolated pig eyes and comparison with standard liquid nitrogen: A pilot ex vivo study
Authors: Barachetti Laura , Giudice Chiara , Cescon Margherita , Mortellaro Carlo M. , Ferrari Roberta , Rampazzo Antonella 
Published: March 2020

AbstractPurposeTo evaluate the immediate effects on cornea and conjunctiva of a cryosurgical method based on the application of a dimethyl ether, propane and isobutene solution (DMEPI, Histofreezer®), and of Liquid Nitrogen (LN2; Cry‐Ac Cryogun®).MethodsA total of 52 isolated pig eyes were obtained at the slaughterhouse, preserved for less than one hour in Ringer Lactate and divided into four groups. The first group included eyes treated with two applications of DMEPI in the center of the cornea, the second group eyes treated with DMEPI on the third eyelid's conjunctiva, the third group eyes treated with LN2 on the third eyelid's conjunctiva and the fourth group included eyes treated with LN2 on the central cornea. Each cryogen application (0.8 cm area) lasted 40 seconds. Each group included one (untreated) control eye. The eyes were submitted for routine histopathological evaluation. Histological alterations were recorded and scored with a semiquantitative scoring system.ResultsNo tissue alteration was detected on the conjunctiva, in any of the groups. Treated corneas showed mild to moderate cytoplasmic vacuolization of epithelial cells, shrinkage and hypereosinophilia of small groups of basal epithelial cells and stromal cleft formation.ConclusionsSoft cryosurgery caused no severe acute histologically detectable damage to cornea and conjunctiva in isolated pig eyes, and no significant difference was observed when LN2 and DMEPI treatments were compared. Further in vivo studies should be performed in order to verify possible delayed effects and the clinical efficacy of DMEPI cryosurgery in specific corneal and/or conjunctival diseases.
Lifetime Model for the Fatigue Fracture in Cu/Al2O3/Cu Composites: Experimental Validation of a Substantial Lifetime Enhancement by Cu Step Etching
Authors: Gaiser Patrick , Klingler Markus , Wilde Jürgen 
Published: March 2020

AbstractDirect bonded copper (DBC) alumina (Al2O3) substrates are used in power electronic devices in order to transfer the heat from semiconductor devices to the heat sink and to carry high electric currents. Fatigue-induced cracks in the ceramic result in a diminished heat dissipation, leading to failure of a power device. Hence, a lifetime model concerning this failure mode is necessary. In this paper, a new lifetime model including crack initiation as well as crack propagation for the fatigue fracture of Al2O3-based DBC substrates is presented. It is based on experimental crack detection techniques and finite element method (FEM) simulations including fracture mechanics. For the validation of the lifetime model, experiments are presented which show that by appropriate design of the copper edge, the lifetime of the substrates is increased substantially.
Guidelines for Reduced-Order Thermal Modeling of Multifinger GaN HEMTs
Authors: Pearson Robert , Chatterjee Bikramjit , Kim Samuel , Graham Samuel , Rattner Alexander , Choi Sukwon 
Published: March 2020

Abstract
The increasing demand for tightly integrated gallium nitride high electron mobility transistors (HEMT) into electronics systems requires accurate thermal evaluation. While these devices exhibit favorable electrical characteristics, the performance and reliability suffer from elevated operating temperatures. Localized device self-heating, with peak channel and die level heat fluxes of the order of 1 MW cm−2 and 1 kW cm−2, respectively, presents a need for thermal management that is reliant on accurate channel temperature predictions. In this publication, a high-fidelity multiphysics modeling approach employing one-way electrothermal coupling is validated against experimental results from Raman thermometry of a 60-finger gallium nitride (GaN) HEMT power amplifier under a set of direct current (DC)-bias conditions. A survey of commonly assumed reduced-order approximations, in the form of numerical and analytical models, are systematically evaluated with comparisons to the peak channel temperature rise of the coupled multiphysics model. Recommendations of modeling assumptions are made relating to heat generation, material properties, and composite layer discretization for numerical and analytical models. The importance of electrothermal coupling is emphasized given the structural and bias condition effect on the heat generation profile. Discretization of the composite layers, with temperature-dependent thermal properties that are physically representative, are also recommended.
Influence of Frequency-Dependent Friction Modeling on the Simulation of Transient Flows in High-Pressure Flow Pipelines
Authors: Ferrari Alessandro , Vento Oscar 
Published: March 2020

Abstract
Frequency-dependent friction can be an important dissipative factor for unsteady flows. In this research investigation, various popular models have been reviewed thoroughly and then applied to evaluate frequency-dependent friction in high-pressure transient flows. Three piezoresistive transducers were used to measure pressure signals along a 2 m high-pressure pipe: the first and the third signal were assumed as boundary conditions in a homemade code that is able to solve the velocity and pressure fields along the pipe. The simulation pressure data have been compared with the pressure signal measured by means of the transducer installed in the middle of the pipe. In addition, an injector model has been applied to a 2 m pipe in order to perform additional simulations in which the rail pressure time distribution and the electrical current time history to the injector are provided as boundary conditions. It has been observed that when frequency-dependent friction is taken into account, more accurate pressure results are generally obtained along the injector supply line than in the case in which the viscous stress is calculated by only taking into account the steady-state Darcy–Weisbach contribution. On the other hand, on the basis of a comparison between the obtained numerical results and experimental traces, the improvement is not related to the method by which the unsteady friction is evaluated. Therefore, the simplest frequency-dependent friction model is recommended to simulate high-pressure transient flows in pipes with a shorter aspect ratio than 800 and lower Reynolds numbers than 104.
Multistability Control of Space Magnetization in Hyperjerk Oscillator: A Case Study
Authors: Leutcho Gervais Dolvis , Kengne Jacques , Fonzin Fozin Theophile , Srinivasan K. , Njitacke Tabekoueng Z. , Jafari Sajad , Borda Monica 
Published: March 2020

Abstract
In this paper, multistability control of a 5D autonomous hyperjerk oscillator through linear augmentation scheme is investigated. The space magnetization is characterized by the coexistence of five different stable states including an asymmetric pair of chaotic attractors, an asymmetric pair of period-3 cycle, and a symmetric chaotic attractor for a given/fixed set of parameters. The linear augmentation method is applied here to control, for the first time, five coexisting attractors. Standard Lyapunov exponents, bifurcation diagrams, basins of attraction, and 3D phase portraits are presented as methods to conduct the efficaciousness of the control scheme. The results of the applied methods reveal that the monostable chaotic attractor is obtained through three important crises when varying the coupling strength. In particular, below the first critical value of the coupling strength, five distinct attractors are coexisting. Above that critical value, three and then two chaotic attractors are now coexisting, respectively. While for higher values of the coupling strength, only the symmetric chaotic attractor is viewed in the controlled system. The process of annihilation of coexisting multiple attractors to monostable one is confirmed experimentally. The important results of the controlled hyperjerk system with its unique survived chaotic attractor are suited in applications like secure communications.
Linear Stability of Momentum Boundary Layer Flow and Heat Transfer Over a Moving Wedge
Authors: Kudenatti Ramesh B. , Misbah Noor E. , Bharathi M. C. 
Published: March 2020

Abstract
This paper studies the linear stability of the unsteady boundary-layer flow and heat transfer over a moving wedge. Both mainstream flow outside the boundary layer and the wedge velocities are approximated by the power of the distance along the wedge wall. In a similar manner, the temperature of the wedge is approximated by the power of the distance that leads to a wall exponent temperature parameter. The governing boundary layer equations admit a class of self-similar solutions under these approximations. The Chebyshev collocation and shooting methods are utilized to predict the upper and lower branch solutions for various parameters. For these two solutions, the velocity, temperature profiles, wall shear-stress, and temperature gradient are entirely different and need to be assessed for their stability as to which of these solutions is practically realizable. It is shown that algebraically growing steady solutions do exist and their effects are significant in the unsteady context. The resulting eigenvalue problem determines whether or not the steady solutions are stable. There are interesting results that are linked to bypass an important class of boundary layer flow and heat transfer. The hydrodynamics behind these results are discussed in some detail.
Progress Toward Roll Processing of Solar Reflective Material
Authors: Smilgys Russell V. , Wallace Steven P. , Kennedy Cheryl E. 
Published: March 2020

Abstract
The goal of this work is to demonstrate that high performance solar reflective material can be produced in a roll format using vacuum deposition techniques. The material consists of a multilayer thin film stack on a substrate. The essential feature of the film stack is an alumina film several microns thick deposited over a silver film. The alumina film is deposited under high vacuum using a physical vapor deposition technique called ion beam assisted deposition (IBAD). The alumina film is optically transparent, scratch resistant, and durable. Its purpose is to protect the silver film and maintain high optical reflectance.
Work on this reflective material began five years ago. Samples were produced on polyester substrates by batch coating. Those samples showed excellent durability in accelerated testing at the National Renewable Energy Laboratory (NREL) in Golden Colorado. The principal limitation to commercialization of the process was a low alumina deposition rate. Over the past three years the alumina deposition rate has been increased from 1 nm/s to 20 nm/s.
The next step is to produce material in a roll format. A roll coater has been built to process 30.48-cm wide rolls of solar reflective material. A steel strip with a highly specular surface finish will be used as the web material. The advantage of this material compared to polyester is that it withstands a higher process temperature and lowers final product installation costs. A major technical challenge will be to reproduce high reflector durability in a continuous, high rate process.
Optimization of Korean Crop Storage Insulation Systems
Authors: Yoon JongHo , Lee Euy-Joon , Krarti Moncef 
Published: March 2020

Abstract
With the increasing concerns with the quality and the safety of foods, several standards and guidelines have been developed to improve the design, construction, and operation of storage warehouses. Several cool storage buildings have been constructed in Korea during the last decade. However, there are no specific standards or guidelines for energy use reduction in refrigerated structures. The main objective of this study to determine the impact of various insulation systems on the total cooling load of the cool storage structures with particular consideration given to the product thermal mass effect to find optimal insulation thickness for each envelope component for various climatic locations in Korea. An energy analysis model was developed using the DOE-2.1E program and over 3500 energy simulations were performed. To determine the optimal configuration for die storage building insulation system, life-cycle cost analysis was conducted. The selection of optimal insulation configuration for each climatic location is based on various criteria including those of crop storage owners and of national energy conservation policy. The results presented in this paper provide easy-to-use design guidelines to select optimal insulation thickness for crop storage facility in Korea.
Dehumidification Through Indirect Nighttime Ventilation
Authors: Abaza Hussein , Beliveau Yvan , Jones Jim 
Published: March 2020

Abstract
Natural ventilation is an important passive cooling strategy. Using cool night air can cool the building structure and lower air conditions energy consumption. However, there are obstacles in using this cooling strategy, including high relative humidity, pollution, limitations in the thermal storage of the building, and low nighttime air temperature. This paper investigates energy savings by indirect ventilation to pre-cool buildings and reduces humidity. The nighttime ventilation strategy is based on optimizing the use of direct and indirect natural ventilation through an air-to-air heat exchanger. This strategy has been tested at the Beliveau House in Blacksburg, Virginia. Simulation results suggest that the indirect ventilation strategy at the Beliveau House reduces inside relative humidity on hot humid summer days by 20%, and the total summer cooling load by 38% when compared to the existing condition.
Ground-Coupled Heat and Moisture Transfer From Buildings: Part 2 — Application
Authors: Deru Michael P. , Kirkpatrick Allan T. 
Published: March 2020

Abstract
In this paper the effects of moisture on the heat transfer from two basic types of building foundations, a slab-on-grade and a basement, are examined. A two-dimensional finite element heat and moisture transfer program is used to show the effects of precipitation, soil type, foundation insulation, water table depth, and freezing on the heat transfer from the building foundation. Comparisons are made with a simple heat conduction model to illustrate the dependency of the soil thermal conductivity on moisture content.
Hybrid Lighting: Designing an Energy-Saving Strategy for Bioregenerative Space Life Support
Authors: Cuello Joel L. 
Published: March 2020

Abstract
The objective of this paper was to provide an overview of current ground-based efforts in the design and development of hybrid lighting systems, combining solar irradiance and electric lighting, to effect reduced electrical power demand for growing plants in a bioregenerative life support system (BLSS) for future space applications on the Moon or Mars. Two experimental Hybrid Solar and Artificial Lighting (HYSAL) systems have been developed: one employing xenon-metal halide (XMH) lamps and the other adopting light-emitting diodes (LEDs) as the electric-lighting components, and both using a mirror-based, fiberoptic-based solar collection system. The results showed that both HYSAL systems provided acceptable spectral quality and lighting uniformity. The apparent electrical conversion efficiency of the HYSAL system with LEDs, however, exceeded that of the HYSAL system with XMH by five-fold. Preliminary simulations of a Martian BLSS indicated that the lighting power required for plant production could be supplemented by the available extraterrestrial solar irradiance by as much as 50%. The use of solar stationary orbits over Mars for an orbiting Martian BLSS to reduce the required electrical power was also suggested.
Roof Integrated Solar Absorber: The Measured Performance of “Invisible” Solar Collectors
Authors: Colon Carlos J. , Merrigan Tim 
Published: March 2020

Abstract
The Florida Solar Energy Center (FSEC), with the support of the National Renewable Energy Laboratory (NREL), has investigated the thermal performance of solar absorbers which are an integral yet indistinguishable part of a building’s roof. The first roof-integrated solar absorber (RISA) system was retrofitted into FSEC’S Flexible Roof Facility in Cocoa, Florida in September 1998. This “proof-of-concept” system uses the asphalt shingle roof surface and the plywood decking under the shingles as an unglazed solar absorber. The absorbed solar heat is then transferred to water that is circulated from a storage tank through polymer tubing attached to the underside of the roof decking. Data collected on this direct 3.9 m2 (42 ft2) solar system for a period of 12 months indicates that it was able to provide an average of 3.4 kWh per day of hot water energy to the storage tank under a 242 liters (64 gal) per day load. The RISA system’s average annual solar conversion efficiency was also determined to be 8 percent, with daily efficiencies reaching a maximum of 13 percent. In addition, a thermal performance equation has been determined to characterize the Phase 1 RISA system’s year-long efficiency under various ambient temperature, insolation, and wind speed conditions.
As a follow-on to the proof-of-concept phase, two prototypes of approximately 4.5 m2 (48 ft2) surface area were constructed and submitted for FSEC thermal performance testing. These Phase 2 RISA prototypes differ in both roof construction and the position of the polymer tubing. One prototype is similar to the “proof-of-concept” RISA system as it employs an asphalt shingle roof surface and has the tubing mounted on the underside of the plywood decking. The second RISA prototype uses metal roofing panels over a plywood substrate and places the polymer tubing between the plywood decking and the metal roofing. Both prototypes were tested according to ASHRAE Standard 93 for determining the thermal performance of solar collectors. From performance data measured both outdoors and indoors using a solar Simulator, FR(ταe)’s were determined to be approximately 18% and 33% for the asphalt shingle and metal roof RISA prototypes, respectively. In addition, the coefficients of linear and second-order efficiency equations were also determined at various wind speeds. Finally, an FSEC thermal performance rating was calculated at the low and intermediate temperature levels. In summary, this paper is a first look at the thermal performance results for these “invisible” solar absorbers that use the actual roof surface of a building for solar heat collection.
Experiences With Using Solar Photovoltaics to Heat Domestic Water
Authors: Dougherty Brian P. , Fanney A. Hunter 
Published: March 2020

Abstract
The solar photovoltaic (PV) industry continues to make progress in increasing the efficiency while reducing the manufacturing costs of PV cells. Economies of scale are being realized as manufacturers expand their production capabilities. Products are commercially available that integrate photovoltaic cells within building façade, fenestration, and roofing components. Legislation and incentive programs by government and commercial entities are supporting both reduced first costs and greater rates of return. The combination of factors support improved cost-effectiveness. As this trend continues, more options for using PV become possible. One such application is a stand-alone, PV-direct, solar water heating application.
Solar water heating can be effectively accomplished by directly using the DC power production from solar photovoltaic modules. A simple controller having multiple power relays connects the PV modules with different combinations of in-tank resistive elements. The controller actively changes the resistive combination so that the photovoltaic modules generate power at or near their maximum output.
The technology, which has been patented and licensed, is applicable to configurations that use a single water heater and to two water heaters that are piped in series. Prototypes using both tank configurations have been in operation at four field sites. This paper emphasizes the single-tank application and the field results from installations in Maryland and Florida.
Field Tests of a PV-Powered Air Monitoring System
Authors: Sanidad L. , Baghzouz Y. , Boehm R. , Hodge Earl 
Published: March 2020

Abstract
A compact stand-alone PV power system was recently designed and built to run an air sampler for environmental monitoring at the Nevada Test Site. This paper presents an overview of the system design and analysis of some of the recorded daily cycles of various power flows during the summer period. The system long-term performance during both high and low solar resource periods is simulated with the computer code PVFORM using historical weather data.
Recommendations for Maximizing Battery Life in Photovoltaic Systems: A Review of Lessons Learned
Authors: Dunlop James P. , Farhi Brian N. 
Published: March 2020

Abstract
This report contains notes, observations and recommendations about the use of batteries in small stand-alone photovoltaic (PV) systems. The conclusions of this work are based on the results of more than a decade’s worth of battery testing at the Florida Solar Energy Center and related work with Sandia National Laboratories, the PV industry and user groups. The most critical findings were the relationship between battery state-of-charge and battery life and the importance of an adequate PV array-to-load ratio.
Photovoltaic Phenomena in Thin Film ZnTe-CdSe Heterojunctions
Authors: Focsha Alexandru , Gashin Petru , Simashkevich Alexei 
Published: March 2020

Abstract
Thin layer ZnTe-CdSe heterojunctions were produced by vapor phase epitaxial growth of ZnTe and CdSe layers on mica and single-crystal ZnSe substrates. These heterojunctions photosensitivity covers the wavelength region of 0.56–0.85 μm. The shape of photosensitivity spectral dependence of ZnTe-CdSe heterojunction depends on the components thickness and their doping level. Thin layer ZnTe-CdSe epitaxial heterojunction parameters under illumination of 80 mW/cm2 (AM1.5) are: FF=0.53, Uoc=0.72V, Isc=14.8 mA/cm2, efficiency η=7.1%. Thin film polycrystalline ZnTe-CdSe heterojunctions having the efficiency η=4.3%, Uoc=0.54 V, Isc=10.6 mA/cm2 were fabricated by using As or Cu doped ZnTe layers and In doped CdSe layers produced by HWT.
TRNSYS Modeling of the SEGS VI Parabolic Trough Solar Electric Generating System
Authors: Jones Scott A. , Pitz-Paal Robert , Schwarzboezl Peter , Blair Nathan , Cable Robert 
Published: March 2020

Abstract
A detailed performance model of the 30 MWe SEGS VI parabolic trough plant was created in the TRNSYS simulation environment using the Solar Thermal Electric Component model library. Both solar and power cycle performance were modeled, but natural gas-fired hybrid operation was not. Good agreement between model predictions and plant measurements was found, with errors usually less than 10%, and transient effects such as startup, shutdown, and cloud response were adequately modeled. While the model could be improved, it demonstrates the capability to perform detailed analysis and is useful for such things as evaluating proposed trough storage systems.