Annals of West University of Timisoara Physics最新文献

Drag Coefficient Estimation of Low Density Objects by Free Fall Experiments 用自由落体实验估计低密度物体的阻力系数

Annals of West University of Timisoara Physics Pub Date : 2023-08-28 DOI: 10.2478/awutp-2023-0005

T. Günther, K. A. Hoang

引用次数: 0

Structural, Mechanical, Elastic, Electronic, Magnetic and Optical Properties of Spinel Compounds ATi2S4 (A=Ca, Sr and Ba): AB Initio Study 尖晶石化合物ATi2S4 (A=Ca, Sr和Ba)的结构、力学、弹性、电子、磁性和光学性质:从头算研究

Annals of West University of Timisoara Physics Pub Date : 2023-08-04 DOI: 10.2478/awutp-2023-0003

Mohammed Nadir Bousahla, Mohammed Alaa Bousahla, A. Chahed, Z. Bousahla, H. Rozale, H. Bendjilali

引用次数: 1

Uncertainties in Clear-Sky Solar Irradiance Modeling Induced by the Limited Availability of the Atmospheric Parameters 大气参数有限可用性导致晴空太阳辐照度模拟中的不确定性

Annals of West University of Timisoara Physics Pub Date : 2023-08-04 DOI: 10.2478/awutp-2023-0004

E. Carstea, M. Paulescu

引用次数: 0

The Performance of a Photovoltaic Cell Coupled with a Thermoelectric Generator 光伏电池与热电发电机耦合的性能研究

Annals of West University of Timisoara Physics Pub Date : 2023-04-17 DOI: 10.2478/awutp-2023-0002

V. Ordodi, I. Borlea, D. A. Vereș, C. Stănese, B. F. Mercè

引用次数: 0

Analysis of Graphene Pythagoras Tree Fractal Antenna with Thin SiO2 Substrate in Terahertz Regime 薄SiO2衬底石墨烯毕达哥拉斯树分形天线在太赫兹波段的分析

Annals of West University of Timisoara Physics Pub Date : 2023-04-10 DOI: 10.2478/awutp-2023-0001

Zakarya Hafdi, Zinelabiddine Mezache, Jun-Lei Tao, Ghada Guergour

{"title":"Analysis of Graphene Pythagoras Tree Fractal Antenna with Thin SiO2 Substrate in Terahertz Regime","authors":"Zakarya Hafdi, Zinelabiddine Mezache, Jun-Lei Tao, Ghada Guergour","doi":"10.2478/awutp-2023-0001","DOIUrl":"https://doi.org/10.2478/awutp-2023-0001","url":null,"abstract":"Abstract The Pythagoras Tree Fractal patch is considered on a SiO2 substrate thickness of 1.5 µm to radiate at four frequencies of 4.975THz, 5.38THz, 6.73THz, and 7.61THz with Voltage Standing Wave Ratio (VSWR) ≤ 2. This is a very creative fractal design of a multiband THz antenna, based on a very thin graphene layer, the study proved a value in terms of high radiation efficiency and high gain, at the level of current research we made a comparison study where the design has evidently huge potential regarding applicability for telecommunication technology in the terahertz regime. The demand for high-performance terahertz (THz) antennas has increased significantly in recent years due to their potential applications in various fields such as medical imaging, security screening, and wireless communications. In this paper, the authors present an analysis of a graphene Pythagoras Tree Fractal (GPTF) antenna with a thin SiO2 substrate for THz regime. The GPTF antenna is designed using a fractal geometry approach, which provides multiple resonant frequencies and enhances the overall radiation efficiency. The thin SiO2 substrate is used to reduce the substrate losses and improve the radiation performance of the antenna. The authors use the Finite-Difference Time-Domain (FDTD) software to simulate the performance of the proposed antenna. The results show that the proposed antenna exhibits high gain, low return loss, and wide bandwidth, making it a promising candidate for THz applications.","PeriodicalId":31012,"journal":{"name":"Annals of West University of Timisoara Physics","volume":"143 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88823942","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Experimental Study of Thermal Conductivity of Concrete with Biosourced Material for Saved Energy in Buildings 建筑节能用生物源材料混凝土导热性能试验研究

Annals of West University of Timisoara Physics Pub Date : 2022-11-28 DOI: 10.2478/awutp-2022-0011

Hichem Necib, D. Belatrache, Hafnaoui Goutar, Nesrine Sahraoui

{"title":"Experimental Study of Thermal Conductivity of Concrete with Biosourced Material for Saved Energy in Buildings","authors":"Hichem Necib, D. Belatrache, Hafnaoui Goutar, Nesrine Sahraoui","doi":"10.2478/awutp-2022-0011","DOIUrl":"https://doi.org/10.2478/awutp-2022-0011","url":null,"abstract":"Abstract This study aims to improve the thermal efficiency of concrete slabs by introducing a plant material. This can contribute to the improvement of internal thermal comfort for buildings and this by lower energy consumption. For this, several experiments were carried out at the laboratory, to find the thermal properties of a new innovative building material produced by inserting ALFA (STIPA TENACISSIMA) into a concrete slab. Several mass percentages of ALFA relative to the total mass of the concrete slab (0%, 0.4%, 0.8%, 1.2% and 1.6%) were studied to see the effect of the introduced quantity of this plant on the thermal conductivity of concrete. It was concluded that the insertion of ALFA in the concrete, decreases considerably the thermal conductivity. The best results are noticed for 1.2% of ALFA, whose thermal conductivity of the concrete is reduced up to 50.61%. As a result, heat gains and losses, through wall or slab, are significantly reduced, which reduces the energy consumed by cooling and heating of homes. In addition, the degree-day method was used to calculate the costs of cooling and heating energy for 58 regions in Algeria. The lowest total energy cost is noticed in the TENES region, while the highest energy cost is noticed in the BORDJ B. MOKHTAR region.","PeriodicalId":31012,"journal":{"name":"Annals of West University of Timisoara Physics","volume":"27 1","pages":"158 - 171"},"PeriodicalIF":0.0,"publicationDate":"2022-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90538829","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Short-Term PV Power Forecasting Based on Sky Imagery. A Case Study at the West University of Timisoara 基于天空图像的短期光伏发电预测。蒂米什瓦拉西部大学的案例研究

Annals of West University of Timisoara Physics Pub Date : 2022-11-18 DOI: 10.2478/awutp-2022-0010

Robert Blaga, C. Dughir, Andreea Săbăduş, N. Stefu, M. Paulescu

{"title":"Short-Term PV Power Forecasting Based on Sky Imagery. A Case Study at the West University of Timisoara","authors":"Robert Blaga, C. Dughir, Andreea Săbăduş, N. Stefu, M. Paulescu","doi":"10.2478/awutp-2022-0010","DOIUrl":"https://doi.org/10.2478/awutp-2022-0010","url":null,"abstract":"Abstract This study deals with the performance of PV2-state model in intra-hour forecasting of photovoltaic (PV) power. The PV2-state model links an empirical model for estimating the PV power delivered by a PV system under clear-sky with a model for forecasting the relative position of the Sun and clouds. Sunshine number (SSN), a binary quantifier showing if the Sun shines or not, is used as a measure for the Sun position with respect to clouds. A physics-based approach to intra-hour forecasting, processing cloud field information from an all-sky imager, is applied to predict SSN. The quality of SSN prediction conditions the overall quality of PV2-state forecasts. The PV2-state performance was evaluated against a challenging database (high variability in the state-of-the-sky, thin cloud cover, broken cloud field, isolated passing clouds) comprising radiometric data and sky-images collected on the Solar Platform of the West University of Timisoara, Romania. The investigation was performed from two perspectives: general model accuracy and, as a novelty, identification of characteristic elements in the state-of-the-sky which fault the SSN prediction. The outcome of such analysis represents the basis of further research aiming to increase the performance in PV power forecasting.","PeriodicalId":31012,"journal":{"name":"Annals of West University of Timisoara Physics","volume":"56 1","pages":"148 - 157"},"PeriodicalIF":0.0,"publicationDate":"2022-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88558478","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Investigation of the Optoelectronic and Photovoltaic Properties of YxIN1-xP Alloys using First Principles Calculations 用第一性原理计算研究YxIN1-xP合金的光电和光伏性能

Annals of West University of Timisoara Physics Pub Date : 2022-11-18 DOI: 10.2478/awutp-2022-0009

K. Talbi, Youcef Cherchab, A. Mir, B. Bouhadef

{"title":"Investigation of the Optoelectronic and Photovoltaic Properties of YxIN1-xP Alloys using First Principles Calculations","authors":"K. Talbi, Youcef Cherchab, A. Mir, B. Bouhadef","doi":"10.2478/awutp-2022-0009","DOIUrl":"https://doi.org/10.2478/awutp-2022-0009","url":null,"abstract":"Abstract Structural stability, electronic, optical, and photovoltaic properties of pure and doped InP were evaluated by using first principles calculations via the density functional theory (DFT). The exchange-correlation potential is treated with generalized gradient approximation (GGA-PBE). Additionally, the Tran Blaha modified Becke-Johnson exchange potential (TB-mBJ) is employed, because it gives very accurate results of the band gap in solids. Our results reveal that all compounds are energetically and mechanically stable. It is found that for Y concentrations less than 30%, the favored structure is a Zinc blende-like one, while for Y concentrations greater than 30%, the favored structure is a NaCl-like structure. The substitution of In by Y is found to be able to enlarge the direct bandgap of about 34% (from 1.43 eV to 2.17 eV) and confirms the semiconductor behavior for zinc blende stable structures. The absorption coefficient is reasonably exceeding 105 cm−1 for YxIn1-xP alloys in the case (x=0 and x=25%). The reflectivity shows less than 30% around the energy value of 2 eV and an efficiency of solar cell of 18% can be achieved for Y0.25In0.75P. Also, a thickness of L = 1μm is enough to confirm the experimental data. Regarding to the matching of lattice parameters (a mismatch < 4%) of InP and Y0.25In0.75P and the band gap energy difference made Y0.25In0.75P suitable for optoelectronic and photovoltaic devices in particularity as Tandem solar cells (Y0.25In0.75P/InP) and quantum well (Y0.25In0.75P/InP/Y0.25In0.75P) applications. In the absence of experimental works, our results can be useful for further studies.","PeriodicalId":31012,"journal":{"name":"Annals of West University of Timisoara Physics","volume":"11 1","pages":"126 - 147"},"PeriodicalIF":0.0,"publicationDate":"2022-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74270429","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Actualization of Semi-Empirical Equation for UV Index 紫外指数半经验方程的实现

Annals of West University of Timisoara Physics Pub Date : 2022-10-14 DOI: 10.2478/awutp-2022-0008

Adriana Vasi, N. Stefu

引用次数: 0

Theoretical Investigation of Structural, Electronic, and Optical Properties of ZnSnP2 Semiconductor ZnSnP2半导体结构、电子和光学性质的理论研究

Annals of West University of Timisoara Physics Pub Date : 2022-09-19 DOI: 10.2478/awutp-2022-0006

M. Ouledali, B. Amrani, S. Daoud, S. Louhibi-Fasla, H. Rekab-Djabri, N. Beloufa, S. Bekheira, I. Ouadha

{"title":"Theoretical Investigation of Structural, Electronic, and Optical Properties of ZnSnP2 Semiconductor","authors":"M. Ouledali, B. Amrani, S. Daoud, S. Louhibi-Fasla, H. Rekab-Djabri, N. Beloufa, S. Bekheira, I. Ouadha","doi":"10.2478/awutp-2022-0006","DOIUrl":"https://doi.org/10.2478/awutp-2022-0006","url":null,"abstract":"Abstract The structural, electronic, and optical properties of ZnSnP2 compound were determined using the first principles calculations. We applied the full-potential enhanced plane wave method (FP-LAPW) within the framework of density functional theory (DFT) as implemented in the Wien2k package. The exchange-correlation potential term was treated using the local density approximation (LDA), the generalized gradient approximation (GGA), the Engel–Vosko generalized gradient approximation (EV–GGA) and GGA plus modified Becke– Johnson (mBJ). The lattice parameters of the ZnSnP2 obtained by minimizing the total energy are consistent well with the existing theoretical and experimental results. The Dugdale and MacDonald Grüneisen parameter was found to be 1.43 from the GGA and 1.44 from the LDA, respectively. According to the electronic properties, the band structure analysis of ZnSnP2 shows that it has a direct band gap in the (Γ-Γ) direction with a value of 1.43 eV. We have investigated the optical properties of ZnSnP2 semiconducting compound. The data of the dielectric functions shown that the peaks are positioned at around 2.41, 3.21, 3.83 and 4.09 eV, respectively.","PeriodicalId":31012,"journal":{"name":"Annals of West University of Timisoara Physics","volume":"1993 1","pages":"82 - 94"},"PeriodicalIF":0.0,"publicationDate":"2022-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89037059","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0