Comparative Study of Experimental and Theoretical Model of Highly-efficient GaInP/Si Tandem Solar Cells

Rached Ganouni,Mourad Talbi,Hatem Ezzaouia 대한전자공학회 2017 Journal of semiconductor technology and science Vol.17 No.6

Si based tandem solar cells speak to a contrasting option to conventional compound III-V multi-junction cells as a promising approach to accomplish high efficiencies. In this paper, we compare between an experimental model of a novel 4-terminal tandem cell design with a back-junction back-contacted (BJBC) c-Si and a theoretical model (proposed in this work) of a new structure of tandem solar cell based on c-Si using Matlab code. The obtained results from the computation of the overall efficiency η, show that we can attain the same efficiency (η = 28%) compared to the experimental model, but with less cost. Moreover, the physics coherence problem is solved with our model.

Edge-Based Individualized Anomaly Detection in Large-Scale Distributed Solar Farms

Ali Reza Sajun,Salsabeel Shapsough,Imran Zualkernan,Rached Dhaouadi 한국통신학회 2022 ICT Express Vol.8 No.2

Power output from large-scale solar farms is often plagued by anomalies that can adversely impact grid integration. This paper presents an anomaly detection system that used Siamese-twin neural networks for anomaly detection on edge devices in a solar farm. The model achieved an F1-score of 0.88 and was evaluated using two multi-threading schemes on a Raspberry PI, Nvidia Nano and Google Coral. A single analytics edge device could service 512 solar panels at 1 Hz. The best hardware platform was Nvidia’s Nano using a TensorFlow Lite model consuming about 35 Wh over 12 h, and with maximum CPU utilization not exceeding 60%.

Three-dimensional modelling of functionally graded beams using Saint-Venant’s beam theory

Mourad Khebizi,Hamza Guenfoud,Mohamed Guenfoud,Rached El Fatmi 국제구조공학회 2019 Structural Engineering and Mechanics, An Int'l Jou Vol.72 No.2

In this paper, the mechanical behaviour of functionally graded material beams is studied using the 3D Saint-Venant’s theory, in which the section is free to warp in and out of its plane (Poisson’s effects and out-of-plane warpings). The material properties of the FGM beam are distributed continuously through the thickness by several distributions, such as power-law distribution, exponential distribution, Mori-Tanaka schema and sigmoid distribution. The proposed method has been applied to study a simply supported FGM beam. The numerical results obtained are compared to other models in the literature, which show a high performance of the 3D exact theory used to describe the stress and strain fields in FGM beams.

A Study on the Minimum Paste Volume in the Design of Concrete Mixture

Fowler, David W.,Hahn, Michael De Moya,Rached, Marc,Choi, Doo-Sun,Choi, Jae-Jin Korea Concrete Institute 2008 International Journal of Concrete Structures and M Vol.2 No.2

Optimization of concrete mixing system is very important for the production of quality mixture of concrete and requires very complicated, specialized knowledge as there are a variety of variables that influence the result. One of the methods of optimizing the concrete mixing system is to minimize the volume of cement paste which, in turn, means maximizing the volume of aggregate. The purpose of this study is to determine the minimum volume of cement paste used in the design of concrete mixture and to design the optimum concrete mixing system based on the fluidity of mortar and concrete. In determining the minimum volume of cement paste, experiments of mortar and concrete were performed based on their workability, material segregation and bleeding. Type of aggregate, granularity distribution and sand percentage were used as test parameters and measurements were taken of the distribution of granularity, usage of HRWRA, minimum volume of paste and drying shrinkage and compressive strength of concrete.

A Study on the Minimum Paste Volume in the Design of Concrete Mixture

David W. Fowler,Michael De Moya Hahn,Marc Rached,Doo-Sun Choi,Jae-Jin Choi 한국콘크리트학회 2008 International Journal of Concrete Structures and M Vol.2 No.2

Analysis of torsional-bending FGM beam by 3D Saint-Venant refined beam theory

Ilies Guendouz,Mourad Khebizi,Hamza Guenfoud,Mohamed Guenfoud,Rached El Fatmi 국제구조공학회 2022 Structural Engineering and Mechanics, An Int'l Jou Vol.84 No.3

In this article, we present torsion-bending analysis of a composite FGM beam with an open section, according to the advanced and refined theory of 1D / 3D beams based on the 3D Saint-Venant’s solution and taking into account the edge effects. The (initially one-dimensional) model contains a set of three-dimensional (3D) displacement modes of the cross section, reflecting its 3D mechanical behaviour. The modes are taken into account depending on the mechanical characteristics and the geometrical form of the cross-section of the composite FGM beam. The model considered is implemented on the CSB (Cross- Section and Beam Analysis) software package. It is based on the RBT/SV theory (Refined Beam Theory on Saint-Venant principle) of FGM beams. The mechanical and physical characteristics of the FGM beam continuously vary, depending on a power-law distribution, across the thickness of the beam. We compare the numerical results obtained by the three-beam theories, namely: The Classical Beam Theory of Saint-Venant (Classical Beam Theory CBT), the theory of refined beams (Refined Beam Theory RBT), and the theory of refined beams, using the higher (high) modes of distortion of the cross-section (Refined Beam Theory using distorted modes RBTd). The results obtained confirm a clear difference between those obtained by the three models at the level of the supports. Further from the support, the results of RBT and RBTd are of the same order, whereas those of CBT remains far from those of higher-order theories. The 3D stresses, strains and displacements, obtained by the present study, reflect the 3D behaviour of FGM beams well, despite the initially 1D nature of the problem. A validation example also shows a very good agreement of the proposed models with other models (classical or higher-order beam theory) and Carrera Unified Formulation 1D-beam model with Lagrange Expansion functions (CUF-LE).

The Physical Properties of Granite Microfines and the Workability of Mortar with Granite Microfines

Koehler, Eric,Hahn, Michael De Moya,Trachet, Alison,Rached, Marc,Choi, Jae Jin,Fowler, David Korean Recycled Construction Resources Institute 2009 한국건설순환자원학회지 Vol.4 No.3

This paper summarizes the analysis of granite microfines from California for use in portland cement concrete. For reference, the granite microfines were compared to microfines used in previous International Center for Aggregates Research(ICAR) projects. The particle shape characteristics, based on the packing density results, were assessed and apparent clay content, based on the methylene blue value test, was evaluated. Also, the physical properties of the microfines were confirmed in self-consolidating mortar mixtures.

Laparoscopic hybrid pancreaticoduodenectomy: Initial single center experience

Abdul Rahman Al-Sadairi,Antonio Mimmo,Rami Rhaiem,Francesco Esposito,Linda J. Rached,Ahmad Tashkandi,Perrine Zimmermann,Riccardo Memeo,Daniele Sommacale,Reza Kianmanesh,Tullio Piardi 한국간담췌외과학회 2021 Annals of hepato-biliary-pancreatic surgery Vol.25 No.1

Backgrounds/Aims: Pancreaticoduodenectomy (PD) is the gold standard for the treatment of periampullary tumors. Many specialized centers have adopted the totally laparoscopic or hybrid laparoscopic PD (LPD). However, this procedure has not yet been standardized and serious debate is taking place towards its safety and feasibility. Herein, we report our recent experience whit hybrid-LPD. Methods: During 2019 in our department 56 PD were performed and 21 (37.5%) underwent hybrid-LPD. We have retrospectively reviewed the short-term outcomes of these patients. Results: Main indication was pancreatic adenocarcinoma (71,4%). The median operative time and intraoperative blood loss were respectively 425 min (range, 226 to 576) and 317 ml (range 60 to 800 ml). Conversion to an open procedure was required in 4 patients (19%): 2 with suspected vein involvement, 1 for mesenteric panniculitis and 1 for biliary injury. The post-operative complication rate was 42.8% (9/21). Regarding post-operative pancreatic fistula, three patients (14.2%) had grade B and 1 grade C (4.7%). Median length of hospital stay was 14 days (range 9-23) and 90- days mortality was 4.7%. The mean number of harvested lymph nodes was 17.7 (range 12 to 26). The rate of margins R0 was 80%; R1 >0<1 mm was 10.5% and R1 0 mm was 9.5%. Conclusions: Hydrid–LPD is safe and feasible. Careful patient selection and increasing experience can reduce the risk of post-operative complications.

Bonding effects of cleaning protocols and time-point of acid etching on dentin impregnated with endodontic sealer

Manzoli Tatiane Miranda,Zaniboni Joissi Ferrari,Besegato João Felipe,Guiotti Flávia Angélica,Dantas Andréa Abi Rached,Kuga Milton Carlos 대한치과보존학회 2022 Restorative Dentistry & Endodontics Vol.47 No.2

Objectives This study aimed to investigate the bonding effects of cleaning protocols on dentin impregnated with endodontic sealer residues using ethanol (E) or xylol (X). The effects of dentin acid etching immediately (I) or 7 days (P) after cleaning were also evaluated. For bonding to dentin, universal adhesive (Scotchbond Universal; 3M ESPE) was used. The persistence of sealer residues, hybrid layer formation and microshear bond strength were the performed analysis. Materials and Methods One hundred and twenty bovine dentin specimens were allocated into 4 groups (n = 10): G1 (E+I); G2 (X+I); G3 (E+P); and G4 (X+P). The persistence of sealer residues was evaluated by SEM. Confocal laser scanning microscopy images were taken to measure the formed hybrid layer using the Image J program. For microshear bond strength, 4 resin composite cylinders were placed over the dentin after the cleaning protocols. ANOVA followed by Tukey test and Kruskal-Wallis followed by Dunn test were used for parametric and non-parametric data, respectively (α = 5%). Results G2 and G4 groups showed a lower persistence of residues (p < 0.05) and thicker hybrid layer than the other groups (p < 0.05). No bond strength differences among all groups were observed (p > 0.05). Conclusions Dentin cleaning using xylol, regardless of the time-point of acid etching, provided lower persistence of residues over the surface and thicker hybrid layer. However, the bond strength of the universal adhesive system in etch-and-rinse strategy was not influenced by the cleaning protocols or time-point of acid etching. Objectives This study aimed to investigate the bonding effects of cleaning protocols on dentin impregnated with endodontic sealer residues using ethanol (E) or xylol (X). The effects of dentin acid etching immediately (I) or 7 days (P) after cleaning were also evaluated. For bonding to dentin, universal adhesive (Scotchbond Universal; 3M ESPE) was used. The persistence of sealer residues, hybrid layer formation and microshear bond strength were the performed analysis. Materials and Methods One hundred and twenty bovine dentin specimens were allocated into 4 groups (n = 10): G1 (E+I); G2 (X+I); G3 (E+P); and G4 (X+P). The persistence of sealer residues was evaluated by SEM. Confocal laser scanning microscopy images were taken to measure the formed hybrid layer using the Image J program. For microshear bond strength, 4 resin composite cylinders were placed over the dentin after the cleaning protocols. ANOVA followed by Tukey test and Kruskal-Wallis followed by Dunn test were used for parametric and non-parametric data, respectively (α = 5%). Results G2 and G4 groups showed a lower persistence of residues (p < 0.05) and thicker hybrid layer than the other groups (p < 0.05). No bond strength differences among all groups were observed (p > 0.05). Conclusions Dentin cleaning using xylol, regardless of the time-point of acid etching, provided lower persistence of residues over the surface and thicker hybrid layer. However, the bond strength of the universal adhesive system in etch-and-rinse strategy was not influenced by the cleaning protocols or time-point of acid etching.

Larval development and foraging behavior of Erythrodiplax abjecta (Rambur) (Anisoptera: Libellulidae) in captivity

Fredy Palacino-Rodríguez,Leonardo Rache-Rodríguez,Diego Andrés Palacino,Adolfo Cordero-Rivera 한국응용곤충학회 2020 Journal of Asia-Pacific Entomology Vol.23 No.4

Understanding the life cycle of Neotropical odonate species is essential given our scant knowledge of this region. In this paper, we examine growth ratio between instars, development patterns, and active/passive feeding behavior of the Andean dragonfly Erythrodiplax abjecta (Rambur, 1842). Larvae were obtained from eggs laid by two females in the laboratory and were maintained at 12–34 °C in individual containers until either their emergence or their death. Larvae hatched 26–57 days after laying, and the total development time was determined as being 316 (SD ± 6.6) days, including 13 instars. Larval instars were characterized using six morphometric variables. The foraging behavior was analyzed considering the time of day and the percentage of the background covered by detritus. The growth ratios between successive instars averaged 1.9 for FW pad length, 1.6 for HW pad length and 1.2 for head width, head length, metathoracic leg length, and total length. Neither the active foraging nor the sit-and-wait foraging behavior were affected by either time of the day or the percentage of background covered by detritus. Erythrodiplax abjecta is univoltine and has a slow lifestyle associated with lentic perennial waters, where larval development and growth rates are low. We provide an equation to estimate the E. abjecta larval instars from field specimens.