Mechanical and Thermal Characteristics of Optimized Electrospun Nylon 6,6 Nanofibers by Using Taguchi Method

Saleh S. Abdelhady,Said H. Zoalfakar,M. A. Agwa,Ashraf A. Ali 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.11

This study is an attempt to optimize the electrospinning process to produce minimum Nylon 6,6 nanofibers by using Taguchi statistical technique. Nylon 6,6 solutions were prepared in a mixture of formic acid (FA) and Dichloromethane (DCM). Design of experiment by using Taguchi statistical technique was applied to determine the most important processing parameters influence on average fiber diameter of Nylon 6,6 nanofiber produced by electrospinning process. The effects of solvent/nylon and FA/DCM ratio on average fiber diameter were investigated. Optimal electrospinning conditions were determined by using the signal-to-noise (S/N) ratio that was calculated from the electrospun Nylon 6,6 nanofibers diameters according to "the-smaller-the-better" approach. The optimum Nylon 6,6 concentration (NY%) and FA/DCM ratio were determined. The morphology of electrospun nanofibers is significantly altered by FA/DCM solvent ratio as well as Nylon 6,6 concentration. The smallest diameter and the narrowest diameter distribution of Nylon 6,6 nanofibers (166 ffi 33 nm) were obtained for 10 wt% Nylon 6,6 solution in 80 wt% FA and 20 wt% DCM. An increase of 118%, 280% and 26% in tensile strength, modulus of elasticity and elongation at break over as-cast was obtained, respectively. Glass transition temperature of Nylon 6,6 nanofibers were determined by using differential scanning calorimeter (DSC). Analysis of variance ANOVA shows that NY% is the most influential parameter.

Synthesis, Pharmacological Activity Evaluation and Molecular Modeling of New Polynuclear Heterocyclic Compounds Containing Benzimidazole Derivatives

Fatma A. Bassyouni,Tamer S. Saleh,Mahmoud M. ElHefnawi,Sherein I. Abd El-Moez,Waled M. El-Senousy,Mohamed E. Abdel-Rehim 대한약학회 2012 Archives of Pharmacal Research Vol.35 No.12

Novel heterocyclic compounds containing benzimidazole derivatives were synthesized from 2-(1Hbenzimidazol-2-yl) acetonitrile (1) and arylhydrazononitrile derivative 2 was obtained via coupling of 1 with 4-methyl phenyldiazonium salt, which was then reacted with hydroxylamine hydrochloride to give amidooxime derivative 3. This product was cyclized into the corresponding oxadiazole derivative 4 upon reflux in acetic anhydride. Compound 4 was refluxed in DMF in the presence of triethylamine to give the corresponding 5-(1H-benzimidazol-2-yl)-2-p-tolyl-2H-1,2,3-triazol-4-amine 6. Treatment of compound 6 with ethyl chloroformate afforded 2,6-dihydro-2-(4-methylphenyl)-1,2,3-triazolo[4'',5''-4',5']pyrimido[1,6-a]benzimidazole-5(4H)-one (8). 1,2-bis(2-cyanomethyl-1H-benzimidazol-1-yl)ethane-1,2-dione (10) was synthesized via the condensation reaction of 2-(1H-benzimidazol-2-yl) acetonitrile (1) and diethyloxalate. The reactivity of compound 10 towards some diamine reagents was studied. The in vitro antimicrobial activity of the synthesized compounds was investigated against several pathogenic bacterial strains such as Escherichia coli O157, Salmonella typhimurium, E. coli O119, S. paratyphi, Pseudomonas aeruginosa, Staphylococcus aureus, Listeria monocytogenes and Bacillus cereus. The results of MIC revealed that compounds 12a-c showed the most effective antimicrobial activity against tested strains. On the other hand, compounds 12a, b exhibited high activity against rotavirus Wa strain while compounds 12b, c exhibited high activity against adenovirus type 7. In silico target prediction, docking and validation of the compounds 12a-c were performed. The dialkylglycine decarboxylase bacterial enzyme was predicted as a potential bacterial target receptor using pharmacophorebased correspondence with previous leads; giving the highest normalized scores and a high correlation docking score with mean inhibition concentrations. A novel binding mechanism was predicted after docking using the MOE software and its validation.

Equilibrium and kinetics of calcium–uranyl–carbonate adsorption on silica nanoparticles

Saleh, A. S.,Yun, J. I. Springer Science + Business Media 2017 JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY Vol.314 No.1

On some lower soft separation axioms

S. Saleh,허걸 원광대학교 기초자연과학연구소 2020 ANNALS OF FUZZY MATHEMATICS AND INFORMATICS Vol.19 No.1

The main aim of this paper, is to introduce and study some new weak soft separation axioms in soft spaces by using the notions of soft $\alpha $-open sets and soft $\alpha$-closure. We investigate some of their properties. Some nice results and relations are obtained with some necessary examples.

Thermodynamic and economic analysis of the performance of a direct evaporative cooler working under extreme summer weather conditions

Saleh S. Baakeem,Jamel Orfi,Abdelbasset Bessadok-Jemai 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.4

Riyadh is a desert region characterized by large daily and seasonal ambient temperature variations. Air cooling using mechanical vapor compression requires high energy rates resulting in negative environmental impacts. The use of non-conventional cooling methods such as evaporative cooling is attractive and needs further investigations particularly in such critical weather conditions. This paper deals with the analysis of the performance of a direct evaporative cooling in hot and arid weather conditions. Theoretical models using heat and mass transfer, exergy and cost analysis are first developed and presented. Such models have been systematically validated using available experimental and theoretical results from previous studies. The second part of the work concerns the analysis of the performance of a direct evaporative cooler under a metropolitan central Arabian Peninsula (Riyadh, KSA) weather conditions using average hourly temperature and relative humidity of the month of July. The optimum operating parameters of the cooler have been then selected. The analysis shows that the effect of the cooler effectiveness on the exergy efficiency is not significant. The suitable value of the effectiveness of the evaporative cooler working under summer weather of the studied location is found to be between 0.7-0.8. Such a value achieves comfortable conditions at low cost.

Some new properties on soft topological spaces

S. Saleh 원광대학교 기초자연과학연구소 2019 ANNALS OF FUZZY MATHEMATICS AND INFORMATICS Vol.17 No.3

In this paper, we introduce and study some new soft properties namely, soft $R_0$ and soft $R_1$($SR_i$, for short $i=0,1$) by using the concept of distinct soft points and we obtain some of their properties. We show how they relate to some soft separation axioms in [21]. Also we, show that the properties $SR_0 , {SR}_1$ are special cases of soft regularity. We further, show that in the case of soft compact spaces, ${SR}_1$ is equivalent to soft regularity. Finally, the relations between these properties in soft topologies and that in crisp topologies are studied. Moreover, some counterexamples are given.

Long-Term Outcomes of Posterior Lumbar Interbody Fusion Using Stand-Alone Ray Threaded Cage for Degenerative Disk Disease: A 20-Year Follow-Up

Saleh S. Baeesa,Belen G. Medrano,David C. Noriega 대한척추외과학회 2016 Asian Spine Journal Vol.10 No.6

Study Design: Retrospective study. Purpose: To analyze outcomes of posterior lumbar interbody fusion (PLIF) stand-alone cages. Overview of Literature: PLIF for degenerative disk disease using stand-alone cages has lost its popularity owing to implant-related complications and pseudoarthrosis. Methods: We analyzed the records of 45 patients (18 women, 27 men), operated between January 1994 and December 1996, with a mean follow-up of 18 years 3 months (20 years 3 months–22 years 3 months). Clinical outcomes were measured using visual analogue score (VAS), Oswestry disability index (ODI), Odom’s criteria, and radiological measurements of fusion rate, Cobb angle, and implant-related complications conducted at the preoperative evaluation, hospital discharge, 12-month follow-up, and final follow-up. Results: Preoperative mean VAS (back) was 6.9 and VAS (radicular) was 7.2, with mean improvements (p <0.05) of 2.9 and 3.1, respectively, at the final follow-up. Median preoperative ODI was 64.5, with a mean improvement to 34 and 42 at the 12-month and final follow-ups, respectively (p <0.05). Odom’s criteria at the 12-month follow-up were excellent in 11.2% patients, good in 57.7%, fair in 31.1%, and poor in none of the patients; at the final follow-up, no patient was classified as excellent, 71.1% as good, 22.2% as fair, and 6.7% as poor (p <0.05). Pseudoarthrosis was observed in five patients (11.1%), of whom, three (6.6%) required re-operation. Preoperative disk height was 9.23 mm, which increased to 13.33 mm in the immediate postoperative evaluation and was maintained at 10.0 mm at the final follow-up (p <0.05). The preoperative mean L1–S1 Cobb angle was 34.7°, which changed to 44.7° in the immediate postoperative evaluation and dropped to 39.7° at the final follow-up (p <0.005). Conclusions: PLIF stand-alone cages were associated with good clinical outcomes. Although the fusion rate was excellent, maintenance of disk heights and a lordotic alignment were not achieved in the long term.

The Synergistic Effects of Different Types of Hybridized Synthetic Fibers on Concrete Post-Crack Residual Strength

S. M. Iqbal S. Zainal,Farzad Hejazi,Farah Nora Aznieta Abd. Aziz,Mohd Saleh Jaafar 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.1

The use of fibers in cement composites has been shown to improve the mechanical properties of concrete through the fiber-bridging effect, which implies the fiber’s crack-resisting property. Additionally, the combination of two or more different fibers in the concrete mixture yielded better strength than the individual fibers due to its more versatile applications. Therefore, this study was conducted to investigate the combination of multiple synthetic fibers to improve the concrete residual strength and evaluate the hybridization synergistic effect. Ferro macro-sized fiber (FF) as the primary load-bearing fiber and four different secondary synthetic microfibers comprising Ultra-Net (UN), Super-Net (SN), Econo-Net (EN), and Nylo-Mono (NM) were utilized to develop a total of 16 hybrid fiber reinforced concrete (HyFRC) combinations and the performance were compared against their single-fiber counterpart. The tensile strength, bonding power, physical form, length, and volume fraction of the fibers were measured under the ASTM C1399 test standard in order to calculate the average residual strength (ARS) of concrete in the post-cracking region as well as to assess the synergistic effect of the fiber combination. The results recorded positive fiber synergy for all specimens tested. In addition, the Ferro-Nylo, Ferro-Super, Ferro-Econo, and Ferro-Ultra hybrids improved the ARS compared to the controlled specimens by 20.41, 10.2, 7.48, and 6.12%, respectively.

Observer-Based Control Design for a Class of Nonlinear Systems Subject to Unknown Inputs

Saleh S. Delshad,Thomas Gustafsson,Hamid Reza Karimi,Ali Zemouche 제어로봇시스템학회 2015 제어로봇시스템학회 국제학술대회 논문집 Vol.2015 No.10

This paper deals with the problem of observer-based controller design for a class of nonlinear systems subject to unknown inputs. A novel method is presented to design a controller using estimated state variables which guarantees all the state variables of the closed-loop system converge to the vicinity of the origin and stay there forever. This is done via satisfying several sufficient conditions in terms of nonlinear matrix inequalities. In light of linear algebra, particularly matrix decompositions, the achieved conditions will be converted to a Linear Matrix Inequality (LMI) problem to facilitate the procedure of computing the observer and controller gains. Finally, the effectiveness of the proposed method is illustrated by implementing on a highly nonlinear chaotic system.

Modeling and Forecasting Saudi Stock Market Volatility Using Wavelet Methods

Tariq S. ALSHAMMARI,Mohd T. ISMAIL,Sadam AL-WADI,Mohammad H. SALEH,Jamil J. JABER 한국유통과학회 2020 The Journal of Asian Finance, Economics and Busine Vol.7 No.11

This empirical research aims to modeling and improving the forecasting accuracy of the volatility pattern by employing the Saudi Arabia stock market (Tadawul)by studying daily closed price index data from October 2011 to December 2019 with a number of observations being 2048. In order to achieve significant results, this study employs many mathematical functions which are non-linear spectral model Maximum overlapping Discrete Wavelet Transform (MODWT) based on the best localized function (Bl14), autoregressive integrated moving average (ARIMA) model and generalized autoregressive conditional heteroskedasticity (GARCH) models. Therefore, the major findings of this study show that all the previous events during the mentioned period of time will be explained and a new forecasting model will be suggested by combining the best MODWT function (Bl14 function) and the fitted GARCH model. Therefore, the results show that the ability of MODWT in decomposition the stock market data, highlighting the significant events which have the most highly volatile data and improving the forecasting accuracy will be showed based on some mathematical criteria such as Mean Absolute Percentage Error (MAPE), Mean Absolute Scaled Error (MASE), Root Means Squared Error (RMSE), Akaike information criterion. These results will be implemented using MATLAB software and R- software.