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Effectiveness of Geant4 in Monte Carlo Simulation Studyofphonon Conduction in Sn Host with Si Nanowire Interface Geant4在具有Si纳米线界面的Sn基体中声子传导的蒙特卡罗模拟研究中的有效性
Pub Date : 2019-12-01 DOI: 10.2478/awutp-2019-0001
C. Iheduru, M. Eleruja, B. Olofinjana, O. E. Awe, A. Buba
Abstract We have explored the effectiveness of Geant4 by using it to simulate phonon conduction in Sn Host with Si Nanowire Interface. Our Monte Carlo Simulation shows that the effectiveness of the phonon conduction Geant4 simulation increases when the system attained a steady state of 100 time steps. We have simulated phonon conduction in Sn host with Si nanowire interface using a Geant4Condensed Matter Physics Monte Carlo simulation toolkit in a low cost and less powerful processing computer machine. In the simulation, phonons were displaced inside a computation domain from their initial positions with the velocities and direction vectors assigned to them. A time step was selected so that a phonon can move at most the length of one sub-cell in one time step. Our phonon conduction analysis of SiSn based alloy using Geant4 showed performance enhancement and reasonable predicted thermal values. Numerical predictions of the thermal profile simulations of the values of the temperature in each cell were all within ten percent of the average temperature of Silicon – Tin.
摘要利用Geant4模拟具有Si纳米线界面的Sn宿主体内的声子传导,探讨了其有效性。我们的蒙特卡罗模拟表明,当系统达到100个时间步长的稳态时,声子传导Geant4模拟的有效性增加。我们利用Geant4Condensed Matter Physics蒙特卡罗模拟工具包,在低成本、低功能的处理计算机上模拟了具有Si纳米线界面的Sn主机中的声子传导。在模拟中,声子在给定的速度和方向矢量的作用下从其初始位置在计算域中移位。选择一个时间步长,使声子在一个时间步长内最多移动一个子单元的长度。我们利用Geant4对SiSn基合金的声子传导进行了分析,结果表明SiSn基合金的声子传导性能得到了提高,预测的热值也较为合理。热剖面模拟的数值预测结果均在硅锡平均温度的10%以内。
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引用次数: 0
Spin Coating Method Fabricated of In2O3 Thin Films 旋转镀膜法制备In2O3薄膜
Pub Date : 2019-12-01 DOI: 10.2478/awutp-2019-0005
S. Benramache, Y. Aoun
Abstract In this work, the In2O3 thin films have been fabricated using a spin coating technique; this technique was prepared in our laboratory. The effect of the layer times (3, 5, 7 and 9 times) on optical and structural properties was investigated. In2O3 thin films were fabricated by dissolving 0.2 M of the indium chloride dehydrate InCl3.2H2O in the absolute H2O. The In2O3 thin films were crystallized at a temperature of 600 °C with pending time of 1 hour. The optical property shows that the prepared In2O3 thin films for 3 and 5 times have a transmission of about 85 %. The maximum bandgap energy was 3.69 eV for 5 times and the lowest Urbach energy was 0.47 eV for 9 times. From XDR all fabricated In2O3 thin films having one diffraction crystal plan is (222) peak intensity, this attribution have good crystalline structure with minimum crystallite size of the (222) plan is 59.69 nm. The prepared In2O3 thin films can be used in photovoltaic applications due to the existing phase and higher transmission.
摘要:本文采用自旋镀膜技术制备了In2O3薄膜;这项技术是在我们的实验室里制备的。研究了层数(3、5、7、9)对光学性能和结构性能的影响。将0.2 M氯化铟脱水物InCl3.2H2O溶解在绝对水中制备了In2O3薄膜。在600℃的温度下结晶,等待时间为1小时。光学性能表明,制备的In2O3薄膜经过3次和5次的透射率约为85%。5次最大带隙能量为3.69 eV, 9次最低乌尔巴赫能量为0.47 eV。从XDR上看,所有制备的In2O3薄膜都具有一个衍射晶图(222)峰强度,该属性具有良好的晶体结构,(222)晶图的最小晶粒尺寸为59.69 nm。所制备的In2O3薄膜由于具有良好的相位和较高的透射率,可用于光伏应用。
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引用次数: 2
Solutions of the Dirac Equation in a Bardeen Black Hole Geometry 巴丁黑洞几何中狄拉克方程的解
Pub Date : 2019-12-01 DOI: 10.2478/awutp-2018-0013
C. Sporea
Abstract In this paper we study the Dirac equation in the geometry of a (regular) Bardeen black hole. We will focus on finding new analytical solutions in the vicinity of the black hole horizon. These solutions can be used with the asymptotic solutions (derived in a previous paper) to compute numerical phase shifts that define the scattering amplitudes.
摘要本文研究了(规则)巴丁黑洞几何中的狄拉克方程。我们将集中精力在黑洞视界附近寻找新的解析解。这些解可以与渐近解(在以前的论文中推导)一起用于计算确定散射振幅的数值相移。
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引用次数: 0
Estimating Global Solar Radiation from Routine Meteorological Parameters Over a Tropical City (7.23°N; 3.52°E) Using Quadratic Models 利用常规气象参数估算热带城市(7.23°N)太阳总辐射3.52°E)使用二次模型
Pub Date : 2018-08-01 DOI: 10.2478/awutp-2018-0005
G. I. Olatona
Abstract The need for adequate solar radiation is ever increasing for various applications. However there is an inadequate data of solar radiation in many countries due to the cost of instrument set up. Hence this study investigates two models for estimating solar radiation from routinely measured meteorological parameters. The data were obtained from the International Institute of Tropical Agriculture, Ibadan. The regression coefficients of the quadratic models were determined and used to estimate the global solar radiation for both forward and backward predictions. Their predictive accuracies were compared with four other models and the measured values using standard statistical error indicators. The results showed for forward as compared to backward predictions in bracket root mean square errors 1.2 (1.1); mean bias errors 1.1 (0.8) and mean percentage errors -4.8% (-2.9%) while for backward prediction 1.9 (1.7), 1.7 (1.4) and 7.9% (2.2%) measured in KJm−2day−1 respectively. A positive error value shows an over estimation while a negative value shows an under estimation. The models are versatile for estimating global solar radiation at the horizontal surface, fixing missing data and correcting outliers.
摘要各种应用对充足太阳辐射的需求日益增加。然而,由于仪器设置费用的原因,许多国家的太阳辐射数据不足。因此,本研究探讨了根据常规测量的气象参数估算太阳辐射的两种模式。这些数据来自伊巴丹的国际热带农业研究所。确定了二次模型的回归系数,并将其用于估算全球太阳辐射的正向和反向预测。使用标准统计误差指标将其预测精度与其他四种模型和实测值进行比较。结果表明,与后向预测相比,前向预测的均方根误差为1.2 (1.1);平均偏差误差为1.1(0.8),平均百分比误差为-4.8%(-2.9%),而向后预测的误差分别为1.9(1.7)、1.7(1.4)和7.9%(2.2%),测量时间为KJm−2day−1。误差值为正表示估计过高,而误差值为负值表示估计不足。这些模型在估算水平表面的全球太阳辐射、修复缺失数据和校正异常值方面用途广泛。
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引用次数: 3
Effect of Cu2O Morphology on Photovoltaic Performance of P-Type Dye-Sensitized Solar Cells Cu2O形态对p型染料敏化太阳能电池光电性能的影响
Pub Date : 2018-08-01 DOI: 10.2478/awutp-2018-0007
D. Ursu, A. Dabici, Melinda Vajda, Neli-Camelia Bublea, N. Duțeanu, M. Miclau
Abstract Cuprous oxide with different morphologies (3D hierarchical structure consisting of the micrometer dendritic rods and the porous truncated octahedrons) has been successfully synthesized via a facile one-step hydrothermal method using copper (II) acetate and ethyl cellulose as reactants. The p-type dye-sensitized solar cell based on the micrometer porous structure exhibits approximately 15% increase in JSC and VOC than 3D hierarchical structure. This enhancement could be explained by the high dye loading capacity of this porous structure and lowering the recombination process at the oxide/dye/electrolyte interface.
摘要以乙酸铜(II)和乙基纤维素为原料,采用简单的一步水热法成功合成了具有不同形貌的氧化亚铜(由微米级枝状棒和多孔截断八面体组成的三维分层结构)。基于微米级多孔结构的p型染料敏化太阳能电池的JSC和VOC比3D层次化结构提高了约15%。这种增强可以解释为这种多孔结构的高染料负载能力和降低氧化物/染料/电解质界面的复合过程。
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引用次数: 2
Experimental Assessment of the Meliss Simulation Model Accuracy of the Direct Solar Irradiance in Brasov, Romania 罗马尼亚布拉索夫Meliss太阳直接辐照度模拟模型精度的实验评估
Pub Date : 2018-08-01 DOI: 10.2478/awutp-2018-0003
Camelia Liliana Moldovan, R. Păltănea, I. Visa
Abstract The solar irradiance is the main input parameter when designing solar energy conversion systems. A poor accuracy of the solar irradiance simulation models negatively affect the output energy and the durability of the solar energy conversion system. In the paper, the measured values of the direct solar irradiance in the entire month of July 2016 are analysed and, based on the daily received direct solar energy and the variability of the direct solar irradiance, the days are classified in four categories: clear sky days, partially clear sky days, partially cloudy days and cloudy days. Based on this classification, only four clear sky days were identified in July 2016. The same procedure was applied for the months of July 2013, 2014 and 2015 resulting 13 clear sky days in the entire monitoring period of four years (2013-2016). The measured values of the direct solar irradiance in these 13 selected clear sky days are comparatively analysed against the direct solar irradiance simulated with Meliss clear sky model. Further on, a statistical analysis is performed for the time interval 8:00-16:00 to evaluate absolute, relative and root mean square errors between the measured and simulated values. The results show that the simulation model overestimates, in eleven out of the thirteen clear sky days, the solar direct irradiance in the central part of the day. The measurements were performed in the Renewable Energy Systems and Recycling (RESREC) Research Centre located in the R&D Institute of the Transilvania University of Brasov, Romania.
太阳辐照度是太阳能转换系统设计的主要输入参数。太阳辐照度模拟模型精度较差,影响了太阳能转换系统的输出能量和使用寿命。本文对2016年7月全月的太阳直射度实测值进行了分析,根据日接收的太阳直射能量和太阳直射度的变异性,将其划分为晴天、部分晴天、部分阴天和阴天四类。根据这一分类,2016年7月仅确定了4个晴天。2013年7月、2014年7月和2015年7月采用相同的程序,整个四年(2013-2016年)监测期间有13天晴空。将选取的13个晴空日的太阳直射度实测值与Meliss晴空模式模拟的太阳直射度进行对比分析。进一步,对8:00-16:00时间间隔进行统计分析,评估测量值与模拟值之间的绝对误差、相对误差和均方根误差。结果表明,在13个晴空日中,模拟模型高估了11个晴空日中部的太阳直接辐照度。测量在位于罗马尼亚布拉索夫特兰西瓦尼亚大学研发研究所的可再生能源系统和回收(RESREC)研究中心进行。
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引用次数: 0
Modeling of Daily Global Solar Irradiation in Timisoara by Using a Fuzzy Approach 用模糊方法模拟蒂米什瓦拉日全球太阳辐照
Pub Date : 2018-08-01 DOI: 10.2478/awutp-2018-0004
R. Boata
Abstract This paper proposes a new simple model to forecast daily global solar irradiation one day ahead using the Takagi-Sugeno fuzzy methods. The model is based on solar radiation data measured in Timisoara, Romania. The daily clearness index represents the direct variable used by the fuzzy algorithm. The model forecasts the clearness index at the moment of time t on basis of two previous values measured at time t-1 and t-2. An assessment of the model accuracy is performed.
摘要本文提出了一种新的简单模型,利用Takagi-Sugeno模糊方法提前一天预测全球太阳辐射。该模型基于在罗马尼亚蒂米什瓦拉测量的太阳辐射数据。日清晰度指数是模糊算法使用的直接变量。该模型基于之前在t-1和t-2时刻测量的两个值来预测t时刻的清晰度指数。对模型的精度进行了评估。
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引用次数: 2
Improved Model for Forecasting Global Solar Irradiance During Sunny and Cloudy Days 预测晴天和阴天全球太阳辐照度的改进模式
Pub Date : 2018-08-01 DOI: 10.2478/awutp-2018-0002
B. Burduhos, M. Neagoe
Abstract A precise estimation of the electrical energy produced daily by photovoltaic (PV) systems is important both for PV owners and for electrical grid operators. It can be achieved if the received solar irradiance can be accurately estimated during any type of daily solar profile (clear, cloudy, mixed sky), not only average solar profile for larger periods of time, e.g. one month or season, as used in PV system design. The paper firstly describes an existing mathematical model, based on the Meliss approach, which uses mean monthly coefficients for estimating average direct and diffuse solar irradiance. This model is satisfactory for monthly/annual intervals but is not useful for daily estimations. Therefore in the second part of the paper an algorithm which allows to generate daily variations of the model’s coefficients for clear and cloudy sky conditions is proposed. The improved model with variable coefficients was tested during several representative days and can be used for estimating the effect which different meteorological conditions as fog/dew/frost have on the quantity and quality of the solar irradiance received by a PV convertor.
准确估算光伏发电系统每天产生的电能对光伏发电用户和电网运营商都很重要。如果能够在任何类型的每日太阳轮廓(晴朗、多云、混合天空)中准确地估计接收到的太阳辐照度,而不仅仅是光伏系统设计中使用的较长时间(例如一个月或一个季节)的平均太阳轮廓,就可以实现这一目标。本文首先描述了一个现有的基于Meliss方法的数学模型,该模型使用平均月系数来估计平均直射和漫射太阳辐照度。这个模型对于每月/每年的间隔是令人满意的,但是对于每天的估计是无用的。因此,在论文的第二部分提出了一种算法,该算法允许在晴朗和多云的天空条件下生成模型系数的日变化。改进的变系数模型在几个有代表性的日子里进行了测试,可以用来估计不同气象条件(如雾/露/霜)对光伏变流器接收太阳辐照度的数量和质量的影响。
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引用次数: 1
Fluid Flow Control in Domestic Hot Water Systems During Days with Different Radiative Stability Levels 不同辐射稳定水平下生活热水系统的流量控制
Pub Date : 2018-08-01 DOI: 10.2478/awutp-2018-0009
S. Budea, V. Badescu
Abstract This paper presents models/strategies for optimum performance of solar collector in closed loop systems. These models aim to maximize the obtained energy by thermal conversion of solar energy. The mass flow rate of the fluid from the primary circuit of the system is the control parameter. The semi empirical models and optimal control methods are in brief presented. The volume of the storage tank is important and the ratio Vs/Ac between this volume and area of the collectors is a key factor in appropriate sizing of the DHW system. Therefore, the paper establishes a relationship between this ratio and the mass flow rate of the fluid in the collector This paper also analyses the variation of the energetic performance (useful heat flux transferred to the storage tank, heat flux transferred to the water, water temperature in the storage tank) with the volume of the storage tank. Analysis was performed on an extensive set of meteorological data from Timisoara, Romania, with instantaneous data (measured at 15 seconds) for summer days, from July 2009, with different relative sunshine values, σ. Important differences have been observed between days with different stability levels - days more or less stable.
摘要本文提出了闭环系统中太阳能集热器性能最优的模型/策略。这些模型旨在最大限度地利用太阳能的热转换所获得的能量。系统一次回路流体的质量流量为控制参数。简要介绍了半经验模型和最优控制方法。储罐的体积很重要,该体积与集热器面积之间的Vs/Ac比率是DHW系统适当尺寸的关键因素。因此,本文建立了该比值与集热器内流体质量流量的关系,并分析了能量性能(传递给储罐的有用热流密度、传递给水的热流密度、储罐内水温)随储罐体积的变化规律。对罗马尼亚蒂米什瓦拉地区2009年7月以来具有不同相对日照值σ的夏季瞬时(15秒)气象资料进行了分析。在稳定程度不同的日子(稳定或不稳定的日子)之间观察到重要的差异。
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引用次数: 0
Impact of Aerosol on the Estimation Accuracy of Solar Radiation 气溶胶对太阳辐射估算精度的影响
Pub Date : 2018-08-01 DOI: 10.2478/awutp-2018-0010
Calinoiu Delia-Gabriela, Paulescu Marius
Abstract The paper is focused on the solar irradiance estimation in clear-sky conditions and an aerosol-loaded atmosphere. Two parametric models developed by our group and three empirical models are tested. The estimates of the parametric models are based on three atmospheric parameters (ozone, nitrogen dioxide and water vapor column content) and the aerosol properties quantified by means of several specific parameters (Ångström turbidity coefficient, single scattering albedo, asymmetry factor). The empirical models contain no inputs for aerosol properties. Data collected from 10 stations were used to test the models. The inputs for the parametric models were retrieved from Aerosol Robotic Network - AERONET. Global and diffuse solar irradiance data at high-quality standards were retrieved from the Baseline Surface Radiation Network BSRN. A comparative analysis of the models’ accuracy in estimating clear-sky solar irradiance is discussed from the perspective of aerosol proprieties.
摘要本文主要研究了晴空条件下大气气溶胶负荷下太阳辐照度的估算。本文对两个参数模型和三个实证模型进行了检验。参数模式的估计是基于三个大气参数(臭氧、二氧化氮和水蒸气柱含量)和几个特定参数(Ångström浊度系数、单次散射反照率、不对称因子)量化的气溶胶特性。经验模式不包含气溶胶特性的输入。从10个站点收集的数据用于测试模型。参数模型的输入从气溶胶机器人网络- AERONET中检索。高质量标准的全球和漫射太阳辐照度数据来自基线表面辐射网络BSRN。从气溶胶特性的角度比较分析了模式在估算晴空太阳辐照度时的精度。
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引用次数: 0
期刊
Annals of West University of Timisoara Physics
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