Technical Performance Parameters Research Articles

Sizing and energy management of grid-connected hybrid renewable energy systems based on techno-economic predictive technique

This study intends to construct and optimally run a grid-connected hybrid renewable energy system (HRES) powering a residential building. A special techno-economic multi-objective optimization technique is used for sizing the HRES. In addition, an energy management strategy (EMS) is established as a distinct multi-objective optimization problem to minimize degradation and operating costs while improving system performance. A Bi-level mixed integer non-linear programming (BMINLP) is the framework used to formulate the two-optimization problems. Sizing problem is characterized by the higher level, on contrast; the nested EMS problem within the constraints of the size problem is presented on the lower level. For this investigation, the problem is executed via the MATLAB program. The global optimization toolbox is applied via the Multi-Objective Genetic Algorithm (MOGA) to solve the sizing optimization. While the EMS is executed using the "Intlinprg" mixed integer linear programming (MILP) solver. The technical and economic performance parameters such as degradation, renewable energy fraction (REF), operating, maintenance, and investment costs are evaluated in this study. The primary results reveal that the summer week encounters the lowest total cost and the highest REF, at roughly 99484 $ and 60 %, respectively. Furthermore, the investigation shows that the lowest degradation value attained in the same week with approximately 50.

Effects of high-intensity functional training on physical fitness and sport-specific performance among the athletes: A systematic review with meta-analysis.

This study aims to meta-analyze the impact of high-intensity functional training on athletes' physical fitness and sport-specific performance. A systematic search was conducted in five well-known academic databases (PubMed, Scopus, Web of Science, EBSCOhost, and the Cochrane Library) up to July 1, 2023. The literature screening criteria included: (1) studies involving healthy athletes, (2) a HIFT program, (3) an assessment of outcomes related to athletes' physical fitness or sport-specific performance, and (4) the inclusion of randomized controlled trials. The Physical Therapy Evidence Database (PEDro) scale was used to evaluate the quality of studies included in the meta-analysis. 13 medium- and high-quality studies met the inclusion criteria for the systematic review, involving 478 athletes aged between 10 and 24.5 years. The training showed a small to large effect size (ES = 0.414-3.351; all p < 0.05) in improving upper and lower body muscle strength, power, flexibility, and sport-specific performance. High-intensity functional training effectively improves athletes' muscle strength, power, flexibility, and sport-specific performance but has no significant impact on endurance and agility. Future research is needed to explore the impact of high-intensity functional training on athletes' speed, balance, and technical and tactical performance parameters.

Sizing and energy management of standalone hybrid renewable energy systems based on economic predictive control

This paper aims to design and run a standalone hybrid renewable energy System (HRES) feeding residential building load. The suggested HRES encompasses photovoltaic panels and wind turbines as energy sources, combined with a hydrogen subsystem and a bank of batteries for energy storage. The meteorological input data includes irradiance, temperature, and wind speed for four seasonal weeks. These data sets are collected for a rural site situated in the town of Ras Munif, northern Jordan. The load profiles characterize a selected benchmark residential building. Consequently, a bi-level mixed integer nonlinear programming (BMINLP) problem is formulated to incorporate the designing problem with the energy management process. The upper level represents the sizing problem, while the lower level problem denotes the energy management strategy (EMS). Each problem has its independent objective function, constraints, and optimization variables. The EMS is an economic-based single objective optimization problem expressed as a mixed integer linear programming (MILP) problem. On the contrary, a mixed integer nonlinear programming (MINLP) approach frames the sizing problem to optimize a techno-economic-based multi-objective function. The interaction between the two problems is that the lower problem is an embedded constraint of the upper problem. Moreover, the candidate solutions from the upper problem are treated as fixed parameters in the lower problem. A multi-objective genetic algorithm is used to execute the overall problem by the MATLAB toolbox. The technical and economic performance parameters, including the investment cost, maintenance, operating costs, and others, are assessed based on the best findings. The key finding demonstrates that the summer week has the lowest total cost and energy loss factor, with around 132,000 $ and 0, respectively. Furthermore, the findings reveal that the entire system's energy loss factor for each sample period is less than 0.0009. This value is substantially less than the permitted limit of 0.01.

Sounding of the Atmosphere Using Broadband Emission Radiometry (SABER): Instrument and Science Measurement Description

AbstractSABER (Sounding of the Atmosphere using Broadband Emission Radiometry) is a 10‐channel infrared radiometer that is one of four instruments on the NASA TIMED (Thermosphere‐Ionosphere‐Mesosphere Energetics and Dynamics) satellite mission to study the structure, energetics, chemistry, and dynamics of the Earth's mesosphere and lower thermosphere. Each of the ten SABER channels has a unique filter over its detector. The filter passes infrared radiation within a defined spectral region that optimizes the ability to derive temperature and constituent concentrations from the infrared radiance measurements. The TIMED spacecraft was launched into a 625 km circular polar orbit (74.1° inclination) via a Boeing Delta II rocket from Vandenberg Air Force Base on 7 December 2001. SABER continues to operate nominally and collect data routinely as it has for over 21 years. Nearly 2,200 peer‐reviewed journal articles have been published worldwide using SABER data. A list of these articles is included in Supporting Information S1 accompanying this paper. This paper presents a detailed technical description of the SABER instrument including major subsystems of the instrument and technical performance parameters. This paper comprehensively describes the instrument and its components and provides final instrument design and performance parameters. The motivation for this paper is to document this information permanently for future reference. The Space Dynamics Laboratory (SDL) of Utah State University designed, fabricated, and calibrated the SABER instrument in close collaboration with NASA Langley Research Center, Hampton University, and Global Atmospheric Technologies and Science (GATS).

Is ball-possession style more physically demanding than counter-attacking? The influence of playing style on match performance in professional soccer.

In soccer, the offensive style of play describes characteristic behavioral features of the players at team level during the offensive phase of matches. This study aimed to investigate the effect of offensive playing style (i.e., while in ball possession) on physical and technical match performance during offensive play as well as success-related factors. The sample consisted of official tracking and event data of 153 matches of the 2020/21 German Bundesliga season. For every team in every match an offensive playing style coefficient was calculated to locate teams on a continuum between ball possession and counter-attacking style. This calculation contains 11 technical and physical performance parameters and has already been validated. In addition, dependent physical (e.g., sprinting distance), technical (e.g., passes), and success-related (e.g., goals) variables were examined. A separate linear mixed model was calculated for each dependent variable. While teams with lower playing style coefficient values (= counter-attacking style) covered more high-intensity (p ≤ 0.01; R2 = 0.13) and sprinting distances per second in possession (p ≤ 0.01; R2 = 0.14), teams with higher playing style coefficient values (= ball possession style) were physically more demanded over a whole match (e.g., more accelerations (p ≤ 0.01; R2 = 0.69), decelerations (p ≤ 0.01; R2 = 0.69), high-intensity (p ≤ 0.01; R2 = 0.36), sprint distance (p = 0.03; R2 = 0.08)). Furthermore, teams with higher playing style coefficient values played more horizontal passes (p ≤ 0.01; R2 = 0.73) and revealed better passing success rates (p ≤ 0.01; R2 = 0.17). In contrast, teams with lower playing style coefficient values played more long passes (p < 0.01; R2 = 0.58). The influence of the playing style coefficient on success-related variables was smaller (p ≤ 0.36; R2 = 0.10-0.13). Concluding, offensive playing style affects physical and technical match performance, but has limited influence on success. Hence, coaches can use the findings to optimize training contents to prepare players for the physical demands of a match.

The Introduction of an MR-Conditional Prototype for Cardiopulmonary Bypass Support: Technical Aspects and System Requirements

Introduction: The use of cardiopulmonary bypass (CBP; also known as a heart-lung machine) in newborns with complex congenital heart defects may result in brain damage. Magnetic resonance imaging (MRI) assessments cannot be performed safely because the metal components used to construct CBP devices may elicit adverse effects on patients when they are placed in a magnetic field. Thus, this project aimed to develop a prototype MR-conditional circulatory support system that could be used to perform cerebral perfusion studies in animal models. Methods: The circulatory support device includes a roller pump with two rollers. The ferromagnetic and most of the metal components of the roller pump were modified or replaced, and the drive was exchanged by an air-pressure motor. All materials used to develop the prototype device were tested in the magnetic field according to the American Society for Testing and Materials (ASTM) Standard F2503-13. The technical performance parameters, including runtime/durability as well as achievable speed and pulsation behavior, were evaluated and compared to standard requirements. The behavior of the prototype device was compared with a commercially available pump. Results: The MRI-conditional pump system produced no image artifacts and could be safely operated in the presence of the magnetic field. The system exhibited minor performance-related differences when compared to a standard CPB pump; feature testing revealed that the prototype meets the requirements (i.e., operability, controllability, and flow range) needed to proceed with the planned animal studies. Conclusion: This MR-conditional prototype is suitable to perform an open-heart surgery in an animal model to assess brain perfusion in an MR environment.

Specific Sound Production Techniques in Academic Guitar Music

"The article is focused on the problematic research area in the borderline between performance, musical and composer’s interests in academic guitar music. Modern growth trends have been identified in the sound production experimental reserves being not typical for the classical guitar performance stroke in concert practice until the early 20th century. A specific method typology of sound production has been proposed: using the technical performance parameters, phonic and visual sound effects, the origin, and primary, authentic realms of life. The connections with similar processes in other instrumental areas have been traced. The light has been thrown on technical and aesthetic facets. The specific methods in sound production stroke, the tone quality and acoustic characteristics varying in range, the expanded visual noise sound effects, and graphic images in the score have been examined. The artistic music samples of the whole generation of experimental composers, namely the French ones: Maurice Ohana, Roland Dyens, Francis Kleynjans and the Chilean ones: Juan Antonio Sánchez, Gustavo Becerra Schmidt analyzed through specific methods of guitar sound extraction have resulted in marked imaginative connections and associations with the content core of musical works. Keywords: guitar music, specific methods of sound extraction, modern guitar concert practice "

Evaluation and comparison in caffeine extraction under green conditions: Solvent selection and ultrasound‐assisted process

AbstractThis study compared the green solvents ethyl acetate and water for caffeine extraction from coffee pills against four traditional solvents (ethanol, methanol, acetone, and acetonitrile). Each solvent's green degree (GD) was calculated using seven environmental and technical performance parameters. The environmental parameters were obtained from the Glaxo Smith Kline guide. Fick's law of effective diffusion was used as the technical parameter. Water was selected as the preferred solvent (among the six evaluated in this study), and its ultrasound‐assisted extraction (UAE) conditions were optimized. The optimal conditions were estimated by ridge analysis. It was found that caffeine extraction was approximately 4.3 times higher in UAE than in conventional solid–liquid processes, and the extraction time was reduced by 96%. Moreover, this process improved caffeine extraction with water. Therefore, the use of UAE over conventional solid extraction and water as an inexpensive, easily accessible, manageable, and environmentally friendly solvent provides extraction alternatives for caffeine in different matrices. Additionally, a methodology is proposed to evaluate the GD for each solvent in the green chemistry framework to achieve sustainable development goals.

Optimization and energy assessment of technological process for CO2 capture system of natural gas and coal combustion

Flue gas stream generated from combusted natural gas, petroleum, and coal in power plants contains enormous CO2 with detrimental effects on the environment. CO2 capture systems must be integrated into these power plants to prevent emissions of CO2 into the open atmosphere. This work uses rate-based process modelling and a parametric design approach to optimally design large-scale amine-based PCC and compression systems that can be integrated into real 550 MW coal-fired and 555MW NGCC fired power plants. A comparative analysis of energy and economy is also conducted. Based on monoethanolamine (MEA), the process parameters of the post-combustion capture and compression system for CO2 were used as the study baseline. Different amines and alternative flow scheme optimization of the post-combustion capture with compression models are developed for coal and natural gas combined cycle (NGCC) cases and their energy consumption performances compared. Also, the operating and capital costs of the CO2 Capture and Storage (CCS) plant are determined for the overall process of economic evaluation concerning technical and economic performance parameters. The results show that rich solvent cooled recycle (RSR) and lean vapour compression (LVC) process modification under the integration case of CO2 capture and compressed Coal, energy savings of 20.4%, 41.8% and 34.8% for MEA, piperazine activated methyldiethanolamine solution (MDEA+PZ) and piperazine activated monoethanolamine (MEA+PZ) respectively, is possible when compared with the basic situation of MEA. RSR+LVC process modification under the integration case of CO2 capture and compressed NGCC, energy savings of 18.9%, 35.4% and 34.4% for MEA, MDEA+PZ and MEA+PZ, respectively, is possible when compared with the basic situation of MEA. Economic performance: the total annual operating costs of MDEA+PZ, RSR+LVC technological process optimized for the coal case was reduced by approximately 30% compared with the basic situation of MEA, while that for the NGCC case was reduced by 19%. The cost of CO2 avoided for the coal used MDEA+PZ into RSR+LVC technological process optimized capture is decreased by 13% compared with coal captured in MEA basic situation. For the NGCC cases, the cost of CO2 avoided for the NGCC of MDEA+PZ, RSR+LVC process optimized capture is decreased by 7% compared with NGCC with MEA basic case capture.

Estimation of the Production Economic Consequences of Stopping Partial Depopulation in Broiler Production

Simple SummaryPartial depopulation is often used in broiler production to optimize the use of the farm space and rear a larger number of broilers. However, it may increase the risk for the introduction of Campylobacter spp. in the poultry house. A simulation was performed to evaluate the production consequences of a Belgian poultry house performing a 25% partial depopulation at 35 days of age compared with a scenario where the entire flock is slaughtered at 42 days of age. The result showed that stopping partial depopulation leads to a substantial production and profit decrease. To compensate the loss, it would be necessary an increase in meat price.Partial depopulation is the removal and slaughter of part of a flock prior to the final slaughter age, and this practice allows broiler producers to optimize stocking density in broiler houses. However, this practice constitutes a serious break in farm biosecurity that can lead to the introduction of various pathogens in the flock, including Campylobacter spp. In this study, the production of a house performing partial depopulation of 25% of the flock at 35 days of age prior to the final slaughter at 42 days was compared with a production system where partial depopulation was not performed. The differences in production costs, profit, and technical performance parameters were evaluated. The model indicated that stopping partial depopulation reduces the production between 16 to 24%, which results in a 14% reduced profit per kg of live weight, and a 31% reduced profit per production cycle. To compensate the profit loss, it would be necessary to increase the meat price 3% from a starting price of 87.44 cents. For current conventional broiler production, it may be financially challenging to stop partial depopulation practices. Focusing on external biosecurity to avoid the introduction of Campylobacter into poultry houses may be the right compromise.

Technical and commercial viability assessment of liquid-cooled heat sinks for a circuit board with discrete heat loads

In this contribution, existing gaps in the design process of liquid-cooled heat sinks, i.e., the lack of overall performance assessment metrics and commercial viability analyses, are addressed. This work focused on the design of a cost-effective cooling system for a commercial circuit board with multiple and asymmetric heat sources designed and manufactured by an electronics company. The analysis was performed using 3-D computational fluid dynamics simulations across sixteen different cases, focusing on the effect on performance and manufacturing cost of two primary design features of liquid-cooled heat sinks: the inlet and outlet manifolds and heat transfer enhancing features, where pin fins and minichannels were considered. Specifically, the effect of diameter and spacing of the pin fins and the effect of the distribution and length of the mini channels over an unevenly heated surface were parametrically investigated. The tradeoff between thermal and hydraulic performance of the heat sinks was reconciled using an overall performance parameter, which allowed for a single numerical evaluation of the heat sinks’ global performance spanning several operating flow conditions. Likewise, the tradeoff between cost and performance was investigated by comparing the manufacturing cost of the different heat sink designs, including two heat spreader materials. Lastly, a comprehensive assessment of the potential cooling solutions for the circuit board was done by combining the overall performance and manufacturing cost per prototype through a novel parameter proposed herein. The broader liquid-cooled heat sink design approach reported in this work is a missing aspect in similar contributions, as the focus is solely on technical performance parameters, while commercial implementation issues (manufacturability and production cost) are neglected.

The influence of tactical formation on physical and technical match performance in male soccer: A systematic review

The number of investigations that specifically address the influence of formation on soccer performance has increased in recent years. Since there is no overview that summarizes these effects, this systematic review aims to synthesize the available literature on the effects of tactical formation on physical and technical match performance. According to the PRISMA 2020 guidelines, a systematic search was performed (Databases: PubMed and Web of Science). Studies were included, if they reported any physical (e.g., sprinting distance) or technical (e.g., number of passes) match performance parameters and compared at least two different formations. The study outcomes were synthesized descriptively. The effect of formation on physical performance was investigated in ten studies while three studies investigated the effect on technical performance (11 studies included). The studies revealed that formation has an effect on the physical and technical match performance of soccer players both in a team and at a positional level. On a team level, smaller differences were observed for formations that are similar in the number of players in each playing position (i.e., 4-5-1, 4-2-3-1). Furthermore, physical match performance was higher in formations with three defenders (e.g., 3-5-2) in comparison to formations with four defenders (e.g., 4-4-2). On a positional level, all positions were affected in a similar way by formation. Therefore, formation affects the physical and technical match performance of soccer players and if the playing position is also considered, the results become even more meaningful. The studies were very heterogeneous regarding their methodology (i.e., parameters, sample size). The findings can help coaches to design their training programs and to prepare the players for a specific positional role depending on the tactical formation.

237 Stable Performance with Reduced Antibiotic Use in Piglets Vaccinated with an E. coli F4/F18 Vaccine for the Prevention of F18-ETEC Post-weaning Diarrhea

Abstract Post-weaning Escherichia coli diarrhea (PWD) remains a major cause of economic losses for the pig industry. PWD, caused by enterotoxigenic E. coli (ETEC), typically provokes mild to severe watery diarrhea between 5–10 days after weaning. Recently, an oral live bivalent E. coli F4/F18 vaccine (Coliprotec® F4/F18; Elanco) was approved on the European market, which reduces the impact of PWD provoked by F4-ETEC and F18-ETEC. The objective was to compare technical results and antibiotic use following E. coli F4/F18 vaccination with previous standard therapeutic approach under field conditions. A 1600-sow farm (weaning at 26 days) with diagnosed problems of PWD due to F18-ETEC was selected. Piglets were vaccinated at 21 days with the oral live bivalent E. coli F4/F18 vaccine. At weaning, no standard group medication (ZnO and antibiotics) was applied for prevention of PWD. Several performance parameters were collected: treatment incidence (TI100), mortality and days in nursery. Statistical analysis was performed using JMP 14.0 – comparison of means. Oral E. coli F4/F18 vaccination significantly reduced TI100 (7 ± 2 days to 0 ± 1 days; P &amp;lt; 0.05). Mortality rate remained stable (2.05% in Control to 1.96% in Vaccinated group; P &amp;lt; 0.05). Days in nursery (40 ± 3 days) remained at the same level compared to pre-vaccination. The results show that live E. coli F4/F18 vaccination against PWD has led to similar technical performance parameters and mortality, in combination with a significant reduction in medication use. In conclusion, control of PWD through oral vaccination is a successful option in order to prevent piglets from the negative clinical outcomes of F18-ETEC infection during the post-weaning period.

236 Performance and Antibiotic Use of Piglets Vaccinated with an E. coli F4/F18 Vaccination for the Prevention of F18-ETEC Post-weaning Diarrhea

Abstract Post-weaning Escherichia coli diarrhea (PWD) remains a major cause of economic losses for the pig industry. PWD, caused by enterotoxigenic E. coli (ETEC), typically provokes mild to severe watery diarrhea between 5 and 10 days after weaning. Recently, an oral live bivalent E. coli F4/F18 vaccine (Coliprotec® F4/F18; Elanco) is available on the European market, which reduces the impact of PWD provoked by F4-ETEC and F18-ETEC. The objective was to compare technical results of E. coli F4/F18 vaccination with previous standard therapeutic approach under field conditions. A 1100-sow farm with diagnosed problems of PWD due to F18-ETEC was selected. Control piglets received the standard treatment protocol with antimicrobials during the post-weaning phase. Vaccinated piglets were immunized at 18 days with the oral live bivalent E. coli F4/ F18 vaccine. At weaning, no standard group medication (ZnO and antibiotics) was applied for prevention of PWD. Piglets were fed a commercial dry feed. Several performance parameters were collected: weight at d0-47, ADWG, ADFI, FCR, TI100 and mortality. Statistical analysis was performed with JMP 14.0 – comparison of means. Oral E. coli F4/F18 vaccination significantly reduced the mortality rate (3.56% to 1.67%; P&amp;lt; 0.05) and TI100 (10 to 0 days; P&amp;lt; 0.05). All other performance parameters (ADWG, ADFI and FCR) were at the same level compared to pre-vaccination. Live E. coli F4/F18 vaccination against PWD resulted in similar technical performance parameters, in combination with a significant reduction in the mortality and medication use. In conclusion, control of PWD through vaccination is a good option in order to prevent piglets from the negative clinical outcomes of F18-ETEC infection during the post-weaning period.

GaAs electro-optic absorption modulators performance evaluation, under high-temperature variations

Abstract This work presents the gallium arsenide (GaAs) electro-optic absorption (EA) modulators performance evaluation compared to the previous models with SiGe EA modulators under high-temperature variations. The average switching speed is studied and analyzed for both EAs. The consumed energy or power per bit is taken into account for both modulators. The modulation depth and transmission coefficient are studied for both previous and proposed EAs with 250 Gb/s at room temperature. The technical performance parameters are also analyzed such as insertion loss, modulation depth, output power, contrast ratio, transmission coefficient, and power length product for both previous and proposed EAs under high-temperature variations. The study assured that to get the optimum GaAs EAs performance efficiency, the modulator length and the thickness should be values of 50 and 5 mm, respectively at room temperature.

Ergonomic Evaluation of Hand Operated Maize Sheller for Reducing Drudgery of Farm Women in Bihar

Maize shelling is one of the tedious and time-consuming agricultural operations. To reduce the drudgery of farm women involved in maize shelling, a hand-held octagonal maize sheller (OMS) tool was introduced. The OMS tool was evaluated for its impact on human health and shelling efficiency. An ergonomic study of the OMS tool was carried out with farm women as subjects for evaluation. Various ergonomic and technical performance parameters were assessed for two types of shelling viz. hand shelling and shelling using OMS tool. The results revealed that the OMS tool and hand shelling recorded an output of 23.71 and 8.87 kg/h, respectively. The cardiac cost per unit of output worked out was 69.73 and 287.09 beats/kg for OMS tool and hand shelling, respectively. Compared to hand shelling, the OMS tool reduced drudgery by 75.71%. Overall discomfort rating was 1.58 and 2.12 while the body part discomfort score was 21.27 and 30.41 for OMS tool and hand shelling, respectively. Adoption of OMS tool reduced the physical stress as very small percentage of subjects (less than 40%) reported about the body pain. In view of increased shelling efficiency and reduced physical pain, the OMS tool was found more suitable and is recommended for maize shelling.

Pick capacity model for cutting machine tools stored in a next generation Vertical Storage Machine

Tools for a group of cutting machine tools in a workshop are often centrally stored, maintained and prepared for use. Using a vertical lift machine (VLM) allows orderly and space-saving storage. It is expected that the total time to prepare tools for delivery in the workshop depends on the chosen VLM architecture and on the strategy for organising the tools in the VLM.This research proposes a mathematical model for determining the total preparation time as a function of the number of items ordered for a series of jobs in the workshop. The model is specific applied for machine cutting tools. While previous research focussed on storage strategies for carrousel storage machines or the basic VLM architecture, this research focusses on five VLM architectures that can be combined with three storage strategies in the mathematical model. The model is largely parametric, allowing for specific numerical values as applicable to the workshop being calculated and allowing to use the technical performance parameters of the VLM.The model illustrates that both the choice of the designated VLM architecture and the choice of storage strategy can have a significant impact on the total time needed to prepare the tools. For both choices to be made, no general rule emerges: a calculation with the specific numerical values for the workshop concerned is appropriate.

Performance evaluation of solar mini-grids in Bangladesh: A two-stage Data Envelopment Analysis

Abstract Solar mini-grids are the solution of choice for the electrification of remote off grid communities across the world. However, studies of comparative performance evaluation of such mini-grids are limited. In this article, we propose performance parameters for off grid distributed electricity generation systems like solar mini-grids, and on this basis evaluate the performance of 21 solar mini-grids which have been in operational in Bangladesh for at least a year, using a two stage Data Envelopment Analysis approach. We look at the efficiencies in terms of project costs, land cost, storage capacity, number of customers served, consumption per customer, rated capacity, power generation, distribution network and annual power consumption. Our findings indicate that all the mini-grids are installed in a relatively cost effective way. However, the market potential in the mini-grid sites is often underestimated or overestimated, leading to inefficiencies. The sensitivity analysis of the models has also been conducted. The effects of uncontrollable factors like solar irradiation, panel efficiency, panel costs, land costs, solar home system penetration and share of commercial users are tested using Tobit models. All these factors except competition from solar home systems affect the efficiencies of the mini-grids. This study is the first to provide a benchmark based comparative analysis of off-grid solar mini-grids, proposing financial and technical performance parameters specifically applicable to the off-grid context.

Bulk crystal growth and characterization of 3-HBST: A promising organic nonlinear optical crystal with high quality

High yield 3-hydroxy benzaldehyde-N-methyl 4-stilbazolium tosylate (3-HBST) was synthesized by optimizing the reaction temperature. High-quality bulk crystals of 3-HBST were grown by slow evaporation technique and spontaneous nucleation method, respectively. The crystal structure of 3-HBST was determined by single crystal X-ray diffraction (XRD) technique and belongs to monoclinic system. The defects of the 3-HBST crystals were observed by the synchrotron radiation X-ray topography. 3-HBST crystal remains stable until 305 °C, with a melting point of 214.1 °C from the TG-DTG and DSC techniques. The dielectric constant of 3-HBST crystal was also studied. The grown crystal had good optical transparency and the optical transmittance was investigated by UV-vis-NIR spectral analysis. Photoluminescence (PL) indicated green emission occurred at 478 nm. Based on the growth technical analysis and performance parameters measurements, 3-HBST crystal was verified to be a promising organic nonlinear optical crystal.

Photovoltaic Solar Systems in Multi-Headquarter Institutions: A Technical Implementation in Northeastern Brazil

The use of photovoltaic solar technology is increasingly widespread and consolidated worldwide, gaining significant interest in Brazil. Thanks to records of gradual photovoltaic system price decreases and the construction of legal frameworks favorable to their diffusion, urban and rural residential consumers, service companies, industries, and the government are progressively adhering to the use of this technology. In this context, it is important that institutions and companies with multiheadquarters discern whether it is more advantageous, from both a technical and economic point of view, to disperse photovoltaic systems throughout all of their headquarters or to centralize them in the offices presenting the best energy efficiency. The present study aims at answering this question. To this end, indicators recorded in the Institute of Education Science and Technology (IFRN)-Solar Project implemented by the Rio Grande do Norte Federal Institute of Education, Science and Technology, in Brazil, where 2 MWp of photovoltaic solar energy are installed in 19 of its 22 headquarters, were evaluated. The PVWatts Software, energy measurements at the different plant installation locations and technical performance parameters recurrent in the literature, as well as the Discounted Payback Method were used herein. The results indicate that system centralization in the best-evaluated sites (7 campi) will, in 25 years, provide a 9.07% energy supply gain, a 112.96% financial gain, and a payback reduction of 8.9 years when compared to the alternative comprising generation unit dispersion throughout the 19 campi.