bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of mechanical properties of glass fibers chopped strands mat composite subjected to UV degradation
Authors: Stanciu M D , Teodorescu H D , Trandafir M , Guţăş V , Savin A 
Published: December 2020

Abstract
The paper focuses on the evaluation of physical and mechanical features of ageing glass fibers chopped strands reinforced polymeric composite, denoted MAT300. First, the samples were analyzed with chroma meter in order to determine the coefficients of color change. Then, the control samples were subjected to three points bending since the other samples were exposed to ultraviolet radiation UV-A radiation for 216 hours. After ageing, the color parameters were measured and the bending test was performed in the laboratory of the Department of Mechanical Engineering at the Transylvania University of Braşov, on the LS100 Lloyd's Instruments type test machine. Results showed the characteristic curves of the fibers glass chopped strands MAT samples, the values of the modulus of longitudinal elasticity, the strain and the breaking stress. Also, the color parameters (lightness, greenness and yellowness scale) were measured, both before and after test, in the rupture zone, considering that the sample break is accompanied by the delamination of the fiber and matrix layers.
Automatic detection of fibers orientation on composite laminates using convolutional neural networks
Authors: Şerban Alexandru , Barsanescu Paul-Doru 
Published: December 2020

Abstract
The mechanical behaviour and failure of the composite materials are highly influenced by the fibre’s orientation. It is important to decide which type of layers and orientations to use for the layup sequence such that the composite laminate is as light and/or cheap as possible while being capable to carry the load for which it is designed. During the production process it is critical to cut and lay the composite woven according to the optimal layup sequence resulting from the optimization process. Therefore, it is important to develop an automatic system which is capable to accurately detect the fibres orientation from a material picture. In our previous work we proposed such a system based on image processing and computational geometry. The main disadvantage of this system is that it has a lot of parameters which need to be manually tuned for each material. In this paper we propose a simple system which doesn’t need any parameter tuning. It is based on convolutional neural networks and we demonstrate with a lot of examples that it is very accurate, stable and insensitive to image variations. The method was tested on diverse composite laminates and woven with different chromatic and morphological properties.
Effects of the hydrogen addition on combustion in automotive diesel engine
Authors: Ene A M , Pana C , Negurescu N , Cernat A , Fuiorescu D , Nutu C 
Published: December 2020

Abstract
Today, fossil fuel replacement and pollutant emissions reduction can be assured by hydrogen use at the automotive diesel engine, obtaining the engine energetic performance improving. The hydrogen has good combustion proprieties. The paper presents some experimental investigations results carried out at an automotive K9K engine diesel at 2000 rev/min speed and 70% load. They showed that hydrogen might be suitable partial substitute of diesel fuel. The hydrogen use assures the thermal efficiency increase due to combustion improvement through homogeneous air-hydrogen mixture rise. The experimental investigations results show that specific energetic consumption decreases with ~8%, the thermal efficiency increases from 31.9% to 34% due to combustion improvement at the hydrogen content increase. In the same time, due to combustion improvement HC and smoke emissions level decreases with 15% respectively 20%. NOx emissions level decreases with 11% comparative to diesel engine at for a 12% percent of substitute ratio of diesel fuel by hydrogen. At the higher percents of substitute ratio of diesel fuel by hydrogen the NOx emissions level increases due to temperature rise. A great advantage is the CO2 emission level decrease with 12% at the increase of percent of substitute ratio of diesel fuel by hydrogen.
Improving brake efficiency by optimizing the design of a car brake caliper
Authors: Gaidur M , Pascal I , Ciobotar C C , Rakosi E , Talif S , Manolache Gh. , Nazare M 
Published: December 2020

Abstract
The continuous advancement in the field of automotive engineering supports the development of new working techniques regarding the definition of new machine parts. In this study, the topological optimization of a tangentially loaded brake caliper is treated. For the first part of the study, the distribution of forces inside the caliper is explained. In the next stage, the computation stage, the working method approached for topological optimization is described. The results and conclusions are commented in the last part of this paper.
Theoretical and experimental possibilities to set up some sensors systems involved in active safety process
Authors: Ispas N , Năstăsoiu M 
Published: December 2020

Abstract
The safety systems present in the construction of modern motor vehicles fully benefit from all development research efforts in the field of autonomous motor vehicles. In this paper, we have analyzed, theoretically and experimentally, for three distinct types of passenger cars, the following active safety systems: 1. Autonomous Emergency Braking system, designed as an automatic braking process of the vehicle, in response to the detection of a probable collision, to reduce the speed of the vehicle; 2. Forward Collision Warning, implemented as an audiovisual warning that is present on board a motor vehicle, to alert the driver; 3. Dynamic Brake support, which further amplifies the braking force to detect the imminent collision to achieve a higher deceleration than in the situation of a normal speed reduction. As a following were study three states such as: Car-to-Car Rear Stationary as a possible collision in which a vehicle travels forwards towards another stationary vehicle and the front structure of the vehicle strikes the rear structure of the other, Car-to-Car Rear Moving as a probable collision in which a vehicle travels forwards towards another vehicle that is travelling at constant speed and the front structure of the vehicle strikes the rear structure of the other and possible collisions named Car-to-Car Rear Braking in which a vehicle travels forwards towards another vehicle that is travelling at constant speed and then decelerates, and the frontal structure of the vehicle strikes the rear structure of the other. The three situations have been examined, experimentally and theoretic, in order to obtain important information about the configurations of sensor systems that compose safety systems. The work allowed to obtain configuration information, experimentally confirmed, with an impact on the improvement of future autonomous vehicles system.
Simulation possibilities of the internal combustion engine management elements using Lotus Engine Simulation software
Authors: Magdas V B , Mastan D C , Burnete N 
Published: December 2020

Abstract
Nowadays the international regulation regarding the exhaust emission and fuel consumption are going in a progressive restricting direction. Authorities force the researchers toward an optimization of new produced engines by lowering the fuel consumption, the harmful exhaust gases and increasing the overall engine efficiency. By lowering the overall quantity of harmful produced gasses, an optimization of the previously produced engines is a good study direction, where the actual engines are analysed and there may be found different ways to upgrade it to a better, more economical and less harmful way of functioning.
The paper approaches the simulation possibilities of the variable valve timing systems using Lotus Engine Simulation software. More precise, it is showed how to use this tool and introduce, modify and analyse the system mentioned above. After simulating different setups of the engine and continuously varying the functionality parameters, useful result shows different ways for further investigations on the engine optimization.
The finite element analysis of pelvic assembly resulted from a pedestrian’s traffic accident. The analysis of the iliac bone
Authors: Pascal I , Ciobotar C C , Gaidur M , Rakosi E , Manolache Gh , Talif S 
Published: December 2020

Abstract
The purpose of this study is to make a series of finite element analyses of the iliac bone of a pedestrian involved in a car crash. The analyses are of a static type. The conditions for the analyses were chosen as to reflect the reality of the situation. The forces which acted on the iliac bone have been experimentally determined. In this study, the authors want to highlight the benefit of the finite element analysis in the road accidentology field.
Modeling and simulating the activities in an automobile repair shop using ARENA software – part 1
Authors: Radulescu I , Tociu A C , Radulescu A V 
Published: December 2020

Abstract
The automobile repair shop market is a highly competitive domain, also filled with opportunities; any competitive advantage can have a significant impact on the chances of success of a firm in this area of activity. The research contains two parts about modeling and simulating the activities in an automobile repair shop, by using ARENA software. Main steps are: simulating the firm's activities by using ARENA simulations software, analyzing the results, continuously seeking and implementing solutions to optimize the experimental model for an efficient use of the available resources. The analyzed automobile repair shop is performing the following services: concierge, diagnosis, mechanical repairs, bodywork and painting, maintenance and periodic technical inspections. Its activities will be simulated for a number of 289 vehicles in a 9600 minutes time interval, representing 20 working days of 8 h/day each, equal to an average working month. The statistical data are collected and studied; it can be observed that there are resources with a low degree of usage, yet with a high number of interventions performed, also others discrepancies in using human resources and equipment. The main results to be obtained are focused in the
The study of cyclic variability at a n-butanol spark ignition engine fueled
Authors: Sandu Cr , Pana C , Negurescu N , Cernat Al , Fuiorescu D , Georgescu R , Nutu C 
Published: December 2020

Abstract
Alcohols such as ethanol, methanol and butanol have gained more attraction in recent years in the use of alternative fuels at the internal combustion engines (ICE) because of their good combustion properties. The use of the butanol-gasoline blends can lead to a decrease in greenhouse gases (CO2) and pollutants such as unburnt hydrocarbons (HC), carbon monoxide (CO) but may increase nitrogen oxides (NOx). An experimental study carried out on a spark ignition engine fueled with a n-butanol-gasoline blend (10% vol. butanol - 90% vol. gasoline) at an engine load χ=55%, speed of n=2500 rpm and different air excess ratios (λ). The objective of this paper is to determine the effects of n-butanol on combustion, specifically on the cyclic variability. So, the COV values for maximum pressure, indicated mean effective pressure and angles of mass fraction burned -10%, 50% and 90%- are presented The engine fueling with butanol-gasoline blend engine leads to the decrease of the cyclic variability and the COV values don’t exceed the recommended value. A great advantage of n-butanol use is the increase of the thermal efficiency due to the stable engine operation and at lean mixtures.
Impact of weather extremes on fresh air ventilation systems
Authors: Adîncu D A , Popescu A , Atanasiu M 
Published: December 2020

Abstract
In the last decades, climate changes start to have a significant impact on society and environment. Extreme temperatures affect more often the functioning of fresh air ventilation systems, as they are designed according to specific standards and norms, without considering the extreme weather events. The main object of this study is to analyze the extreme weather events registered in six major cities from Romania, based on daily observation data for outdoor air temperature variations (minimum and maximum). The analysis covers the outdoor air temperature data recorded by the local weather stations from these cities over a period of 9 years, between 2011 and 2019.
Analysis of a dual-purpose refrigerating and heat pump system
Authors: Dima D , Ionita C , Vasilescu E E , Gheorghian A T , Dobrovicescu A 
Published: December 2020

Abstract
The study is looking for the optimum configuration of a system that requires refrigeration and heating. An ammonia refrigerator separated from a R152a heat pump are first considered. Water is the hot carrying fluid. Based on the exergy analysis, that points out the location and magnitude of each system operational malfunction, an optimization strategy is considered. Following the optimization procedure the two initial separated systems are coupled by using the condenser of the refrigerating unit to preheat water. Due to the exergy destruction in the water preheating condenser, ammonia is replaced by CO2. The transcritical CO2 heater diminish the exergy destruction with the heat transfer across a finite temperature difference. Solutions for further improving the efficiency of the dual-purpose system focus on the decrease in the throttling valve destruction in the CO2 refrigerating unit.
NZEB design principles for affordable single-family housing accounting for regional climatic conditions
Authors: Dumitraşcu A I , Corduban C G , Hapurne T M , Bliuc I 
Published: December 2020

Abstract
The architecture should be specific to a certain place and a certain culture, not only from the standpoint of formal integration in the existing building stock, but also from the perspective of adapting to the regional climatic conditions. Thus, the importance of a “regional” applied concept in the global context regarding NZEB (Nearly Zero Energy Building) design must be emphasized. This paper presents a methodology for evaluation of a NZEB single-family house, taking into account specific climatic characteristics and use of passive design principles for cost optimization. Based on detailed climate data, the most efficient passive measures for the studied region were analyzed. The single-family housing project was evaluated through a BIM (Building Information Modeling) methodology and the result was optimized and compared with National and European standards for NZEB.
Compression ignition engine - sources of pollution
Authors: Istrate A , Bică M , Simion M 
Published: December 2020

AbstractThe high reliability and efficiency of the compression ignition engine as well as its low operating costs turned this engine into the preferred propulsion system for both cars and heavy vehicles. At the same time, the harmfulness of his pollutant emissions gave him the unpleasing status of First Culprit for the many health problems of the population in the metropolis. Currently, the compression ignition engine is mainly responsible for the release of five types of pollutant emissions into the atmosphere: carbon monoxide-CO, hydrocarbons-HC, mechanical particles-PM, sulphur dioxide-SO2 and nitrogen oxides-NOx. Thus, while emissions of carbon monoxide-CO and hydrocarbon-HC are low, due to the fact that this engine usually works with lean mixtures, high emissions of nitrogen oxides-NOx and mechanical particles-PM raise serious pollution problems worldwide.
Air-to-water heat pumps: the impact of climate, compressor technology, water output temperature and sizing on the seasonal coefficient of performance for heating
Authors: Mouzeviris G A , Papakostas K T 
Published: December 2020

Abstract
Air-to-water heat pumps (AWHPs) are devices that will broadly replace heating systems based on fossil fuels. The performance of AWHPs in heating operation is strongly influenced by various parameters such as the climate of the location, the hot water output temperature to the heat emitters, the oversizing or downsizing of the HP with respect to the thermal load of the building, the control system, and the heat pump’s compressor technology (fixed-capacity and inverter-driven HPs). The aim of this work is to study the impact of those parameters on the seasonal efficiency for heating of AWHPs in buildings at representative cities of the four Greek climatic zones. The active mode seasonal coefficient of performance (SCOPon) was estimated in various case studies, with the method proposed in European standard EN 14825, by using climatic data of the four locations. The results show the positive effect of lowering the water supply temperature to the heating system and of using inverter technology and control system with compensation on AWHPs efficiency. Additionally, it is demonstrated that the optimal performance of inverter-driven HPs appears when they are sized at the design outdoor air temperature, while in the case of the fixed-capacity HPs when they are down-sized.
CFD analysis of a round shaped air cushion vehicle with inclined skirt segments
Authors: Pavăl M S , Popescu A , Zahariea D 
Published: December 2020

Abstract
This article presents various two-dimensional CFD analyses specific to the area of the flexible skirt segments for a round-shaped air cushion vehicle. This study aims to analyse the flexible skirt segments and the influence of their inclination angle on the lift force values. The simulations, as well as the geometries of the flow domain, were carried out with ANSYS Fluent software, in which three parameters varied: tilt angle, segment height and air clearance height. The choice of segments height was based on a previous study by the authors and the values for air clearance height imposed in the present study were 10, 20, 30, 40 and 50 mm. Regarding the values of the inclination angles, three values were imposed: 45°, 60° and 75°. Using ANSYS CFD-Post application, the resulting pressure / velocity contours and streamlines are interpreted and with Curve Fitting Toolbox application within the MATLAB program, the curves describing lift forces obtained from the simulation are approximated.
Maximum energy efficiency on photovoltaic solar panels by using an innovative solar tracker
Authors: Sgârciu I A , Cernian A S , Anghel A M , Sgârciu V 
Published: December 2020

Abstract
The solutions currently used for the acquisition of solar energy are based on fixed mechanical structures, in which the photovoltaic panels are either ground-mounted or building-integrated, positioned on suitable rooftops. Both solutions involve the partial take-over of solar energy, thus a reduced energy efficiency of the photovoltaic installation. The solution proposed by the authors of the paper has an innovative mechanical construction and a mixed mode of operation, which combines the secular way with that of the tracking. The operation of the solar tracker presented in the paper is based on the programming in LabVIEW, with the use of a general module for the acquisition/generation of analogue and digital signals. The design developed by the authors has a simple mechanical construction, and the positioning considers the clock of the PC, so that the initial positioning (at start-up) is done in a simplified manner, regardless of the geographical placement of the tracker. The authors performed experiments in the laboratory and in the field, the results being consistent with the theoretical assumptions.
Exergy and performance analyses of impact subcooling for vapor compression refrigeration system utilizing eco-friendly refrigerants
Authors: Tarish A L , Al Douri J , Apostol V , Pop H L , Ionita C 
Published: December 2020

Abstract
In the present paper, performance and exergy analysis for a vapor compression refrigeration system (VCRS) operating with eco-friendly refrigerants such as R1234ze and R1234fyare tested under different operation conditions to change the recently worked refrigerants R-134a. An analysis through performance and exergy is performed to guide the thermodynamic improvement for the VCRS. Additionally, a comprehensive study is conducted to examine the effects of subcooling temperature on performance and exergy destruction in all components of the VCRS. The exergy destruction of the compressors, condenser, evaporator and expansion device were calculated to obtain the exergy efficiencies. For simulation and analysis the VCRS, Engineering Equation Solver (EES) software program was utilized to obtain the thermodynamics refrigerant properties in which the system operates with the highest eco-friendly, energy and exergy performance is developed the VCRS to determine the most suitable alternative refrigerant to replace the R134a. The results indicate that the refrigerant R1234yf showed the greatest COP enhancement 16.7% due to subcooling, followed by R1234ze 14% and R134a 12.8% under the same operating conditions.
Hyperactive MEK1 Signaling in Cortical GABAergic Neurons Promotes Embryonic Parvalbumin Neuron Loss and Defects in Behavioral Inhibition
Authors: Holter Michael C , Hewitt Lauren T , Nishimura Kenji J , Knowles Sara J , Bjorklund George R , Shah Shiv , Fry Noah R , Rees Katherina P , Gupta Tanya A , Daniels Carter W , Li Guohui , Marsh Steven , Treiman David Michael , Olive Michael Foster , Anderson Trent R , Sanabria Federico , Snider William D , Newbern Jason M 
Published: December 2020

Abstract
Many developmental syndromes have been linked to genetic mutations that cause abnormal ERK/MAPK activity; however, the neuropathological effects of hyperactive signaling are not fully understood. Here, we examined whether hyperactivation of MEK1 modifies the development of GABAergic cortical interneurons (CINs), a heterogeneous population of inhibitory neurons necessary for cortical function. We show that GABAergic-neuron specific MEK1 hyperactivation in vivo leads to increased cleaved caspase-3 labeling in a subpopulation of immature neurons in the embryonic subpallial mantle zone. Adult mutants displayed a significant loss of parvalbumin (PV), but not somatostatin, expressing CINs and a reduction in perisomatic inhibitory synapses on excitatory neurons. Surviving mutant PV-CINs maintained a typical fast-spiking phenotype but showed signs of decreased intrinsic excitability that coincided with an increased risk of seizure-like phenotypes. In contrast to other mouse models of PV-CIN loss, we discovered a robust increase in the accumulation of perineuronal nets, an extracellular structure thought to restrict plasticity. Indeed, we found that mutants exhibited a significant impairment in the acquisition of behavioral response inhibition capacity. Overall, our data suggest PV-CIN development is particularly sensitive to hyperactive MEK1 signaling, which may underlie certain neurological deficits frequently observed in ERK/MAPK-linked syndromes.
Perceived risk, environmental attitude and fertilizer application by vegetable farmers in China
Authors: Xiang Zhaoyang , Tian Qingsong , Li Qianling 
Published: December 2020

Abstract
In this study, we investigated the impact of three different perceived risk and environmental attitude on the fertilizer reduction behavior in vegetable production and the interplay between perceived risk and environmental attitude. We found that perceived economic risk can exert a significant and negative effect on farmers’ fertilizer reduction behavior (−0.39) and perceived social and psychological risks has a relatively weak negative impact with coefficients of −0.25 and −0.23, respectively. A more friendly environmental attitude can significantly and positively affect farmers’ fertilizer reduction behavior. Furthermore, environmental attitude has a moderating effect on the association between perceived risk and farmer’s fertilizer reduction behavior, but just significant for economic and social risk. In other words, a better environmental attitude could reduce the negative effect of perceived risk. This study promoted our new understanding of the risk perception’s impact on farmers’ behavior.