Characterization and dielectric studies of hydrogen-beam-irradiated PDMS polymeric materials

Haifa A. Al‑Yousef,B. M. Alotaibi,A. Atta,M. M. Abdel‑Hamid 한국고분자학회 2023 Macromolecular Research Vol.31 No.8

In this work, PDMS films are treated with varying fluence of hydrogen ion beams (6 × 1017, 9 × 1017, and 12 × 1017 ions/cm2) for used in storage energy devices. XRD and FTIR were used to analyze the PDMS films. Furthermore, the SEM is employed to study the morphological alterations in treated PDMS films. Both XRD and FTIR result indicated that PDMS is chemically interacting after ion treatment. In addition, the dielectric parameters of PDMS films are measured using an LCR device in the frequencies 102–106 Hz. After PDMS exposed to 12 × 1017 ions/cm2, the dielectric constant of the PDMS increased from 23.4 to 44.8, and energy density increased from 1.01 × 10–4 to 1.92 × 10–4 J/m3, while the conductivity increased from 0.29 × 10–7 to 4.3 × 10–7 S/cm. Moreover, the real M′ decreased from 0.198 for PDMS to 0.165 for 6 × 1017 ions/cm2 and to 0.052 at 12 × 1017 ions/cm2, while the imaginary M″ is decreased from 0.205 to 0.155 for 6 × 1017 ions/cm2, and to 0.069 for 12 × 1017 ions/cm2. The studies indicated that the structure as well as electrical characteristics of the treated PDMS had been improved, which allowing being used these substances in different electronic instrumentations.

Effects of Short-Term Dried Plum (Prune) Intake on Markers of Bone Resorption and Vascular Function in Healthy Postmenopausal Women: A Randomized Crossover Trial

Yousef A. Al-Dashti,Roberta R. Holt,John G. Carson,Carl L. Keen,Robert M. Hackman 한국식품영양과학회 2019 Journal of medicinal food Vol.22 No.10

Osteoporosis and cardiovascular disease are global health burdens, with postmenopausal women being at great risk. Dried plums/prunes (DPs) have been reported to provide bone health benefits in animal models, which is consistent with in vitro models. Data from human studies suggest that DP intake can enhance lipid metabolism, anti-inflammatory, and oxidant defense systems, which can impact cardiovascular health. We tested the hypothesis that short-term consumption of low and reasonable levels of DPs augments bone resorption and vascular function. Twenty-seven healthy, postmenopausal women were randomly assigned to consume six DPs (∼42 g) or two DPs (∼14 g) per day for 2 weeks, then a 2-week washout period and then crossed over. Serum C-telopeptide, beta-crosslinked (CTX) was used as a measure of bone resorption. Peripheral artery tonometry (PAT) was used to assess microvascular function. The pattern of changes in CTX in the second 2-week period (no change or decline) differed significantly from the pattern in the first 2 weeks (increases in both groups; F = 9.26, P = .006), suggesting a trend in CTX reduction (i.e., a decrease in bone resorption) in those consuming six DPs per day in the second phase. No effects on vascular function were noted. A significant interaction was observed for the augmentation index, a measure of arterial stiffness, between treatment and years after menopause (P = .045). The results suggest a potentially favorable impact of DPs on bone health when assessed with a short-term, crossover study design in postmenopausal women. Given the novel assessments used in this study, follow-up studies are warranted.

Recessive Trait Crossover Genetic Algorithm Flight Control System Design

A. A. El-Mahallawy,A. A. Madkour,A. M. Yousef,H. A. Yousef,M. I. El-Singaby 제어로봇시스템학회 2008 제어로봇시스템학회 국제학술대회 논문집 Vol.2008 No.10

The requirements, design and simulation of a flight control system for precision tracking task, called pitchrate control augmentation system, is considered. This control system is designed for the F-16 fighter aircraft model using the recessive trait crossover genetic algorithm. The behavior of this controller is compared with that of H￥- mixed sensitivity approach. The flight simulations reveal that the desired performance objectives are achieved and that the controller provides acceptable performance in spite of modeling errors and plant parameter variations.

Cu⁰/S-doped TiO₂ nanoparticles-decorated carbon nanofibers as novel and efficient photocatalyst for hydrogen generation from ammonia borane

Yousef, A.,Brooks, R.M.,El-Halwany, M.M.,EL-Newehy, M.H.,Al-Deyab, S.S.,Barakat, N.A.M. Ceramurgica ; Elsevier Science Ltd 2016 CERAMICS INTERNATIONAL Vol.42 No.1

Cu<SUP>0</SUP>/S-doped TiO<SUB>2</SUB> nanoparticles (NPs)-decorated carbon nanofibers (CNFs) were introduced as a novel photocatalyst for the hydrolysis of ammonia borane under visible light. Nanofibers were prepared by electrospinning of a solution composed of titanium isopropoxide, polyvinylpyrroliodine, copper acetate tetrahydrate, and ammonium sulfide. Calcination of the formed nanofiber mats in Ar at 800<SUP>o</SUP>C led to thermal decomposition of CuS to Cu<SUP>0</SUP> and S. Finally, the obtained nanofibers revealed a better photocatalytic activity over that of the other used photocatalysts. The hydrogen evolution was approximately 60mL, 35mL, and 20mL in 40min using nanocatalyst and TiO<SUB>2</SUB>-CNFs, and TiO<SUB>2</SUB> NFs, respectively. The good nanofibrous morphology and electron-transfer, and high surface area are the main features of the introduced nanofibers.

Cadmium-doped cobalt/carbon nanoparticles as novel nonprecious electrocatalyst for methanol oxidation

Barakat, N.A.M.,Abdelkareem, M.A.,Yousef, A.,Al-Deyab, S.S.,El-Newehy, M.,Kim, H.Y. Pergamon Press ; Elsevier Science Ltd 2013 INTERNATIONAL JOURNAL OF HYDROGEN ENERGY - Vol.38 No.8

Cd-doped Cobalt nanoparticles encapsulated in graphite shell have been synthesized using a simple sol-gel technique. Typically, a sol-gel composed of cadmium acetate, cobalt acetate and poly(vinyl alcohol) has been prepared based on the polycondensation property of the acetates. The utilized physiochemical characterizations affirmed that drying, grinding and calcination in Ar atmosphere of the prepared gel leads to produce Cd-doped Co nanoparticles encapsulated in a thin graphite layer. The prepared nanoparticles revealed good electroactivity towards methanol electrooxidation. High current density (70 mAcm<SUP>-2</SUP>) and considerably low onset potential (~600 mV vs. NHE) were obtained. Moreover, because of the graphite shell, good stability was observed. Considering that the introduced nanoparticles composed of nonprecious metals and the obtained electrochemical results are satisfactory, the introduced study might open new avenues for the cobalt-based nanostructures to be used as novel effective electrocatalysts in the fuel cells applications.

Influence of Genotype and Haplotype of MDR1 (C3435T, G2677A/T, C1236T) on the Incidence of Breast Cancer - a Case-Control Study in Jordan

Abuhaliema, Ali M,Yousef, Al-Motassem F,El-Madany, Nirmeen N,Bulatova, Nailya R,Awwad, Nemah M,Yousef, Muhammad A,Al Majdalawi, Khalil Z Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.1

Background: Breast cancer is the leading cause of cancer death among women and the second in humans worldwide. Many published studies have suggested an association between MDR1 polymorphisms and breast cancer risk. Our aim was to study the association between genetic polymorphism of MDR1 at three sites (C3435T, G2677A/T, and C1236T) and their haplotype and the risk of breast cancer in Jordanian females. Materials and Methods: A case-control study involving 150 breast cancer cases and 150 controls was conducted. Controls were age-matched to cases. The polymerase chain reaction/restriction fragment length polymorphism (PCR-RFLP) technique and sequencing were performed to analyse genotypes. Results: The distribution of MDR1 C3435T genotypes differed between cases and controls [cases, CC 45.3%, CT 41.3%, and TT 13.3%; controls, CC 13.4%, CT 43.3%, and TT 30.2%, p < 0.001]. Similarly, the distribution of G2677A/T significantly differed [cases, GG 43.1 %, GT+GA 50.9% and AA+TT 6%; controls, GG 29.6 %, GT+GA 50.9%, and AA+TT 19.4%, p = 0.004]. On the other hand, genotype and allelotype distribution of C1236T was not statistically different between cases and controls (p=0.56 and 0.26, respectively). The CGC haplotype increased the risk to breast cancer by 2.5-fold compared to others, while TGC and TTC haplotypes carried 2.5- and 5-fold lower risk of breast cancer, respectively. Conclusions: Genetic polymorphisms of MDR1 C3435T and G2677A/T, but not C1236T, are associated with increased risk of breast cancer. In addition, CGC, TGC and TTC haplotypes have different impacts on the risk of breast cancer. Future, larger studies are needed to validate these findings.

Prediction of compressive strength of concrete using neural networks

Yousef A. Al-Salloum,Abid A. Shah,Saleh H. Alsayed,Tarek H. Almusallam,M.S. Al-Haddad,H. Abbas 사단법인 한국계산역학회 2012 Computers and Concrete, An International Journal Vol.10 No.2

This research deals with the prediction of compressive strength of normal and high strength concrete using neural networks. The compressive strength was modeled as a function of eight variables: quantities of cement, fine aggregate, coarse aggregate, micro-silica, water and super-plasticizer, maximum size of coarse aggregate, fineness modulus of fine aggregate. Two networks, one using raw variables and another using grouped dimensionless variables were constructed, trained and tested using available experimental data, covering a large range of concrete compressive strengths. The neural network models were compared with regression models. The neural networks based model gave high prediction accuracy and the results demonstrated that the use of neural networks in assessing compressive strength of concrete is both practical and beneficial. The performance of model using the grouped dimensionless variables is better than the prediction using raw variables.

The COVID-19 Pandemic and Instability of Stock Markets: An Empirical Analysis Using Panel Vector Error Correction Model

Yousef M. ABDULRAZZAQ,Mohammad A. ALI,Hesham A. ALMANSOURI 한국유통과학회 2022 The Journal of Asian Finance, Economics and Busine Vol.9 No.4

The objective of this research is to examine the influence of the COVID-19 pandemic on stock markets in a few developing and developed countries. This study uses daily data from January 2020 to May 2021 and obtained from World Health Organization and Thomson Reuters. The secondary data was evaluated through panel econometric methodology that includes different unit root tests, and to analyze the longrun relationship between variables, panel cointegration techniques were applied. The long-run causality among variables was examined through Panel Vector Error Correction Model. The overall findings of this study suggest a long-run association exists between several cases and death with the stock returns of the GCC and other stock markets. Furthermore, the VECM model also identified a long-run causality running from COVID cases and death towards the stock rerun of both sets of stock markets. However, a subsequent Wald test yielded mixed results, indicating no short-run causality between cases and deaths and stock returns in both groups; however, in the case of GCC, several COVID-19 cases are having a causal impact on stock markets, which is notable in light of the fact that the death rate in GCC is significantly lower than in many developed and developing countries.

Cu₀- doped TiO₂ nanofibers as potential photocatalyst and antimicrobial agent

Yousef, A.,El-Halwany, M.M.,Barakat, N.A.M.,Al-Maghrabi, M.N.,Kim, H.Y. Korean Society of Industrial and Engineering Chemi 2015 Journal of industrial and engineering chemistry Vol.26 No.-

Cu<SUB>0</SUB> nanoparticles (NPs)-doped TiO<SUB>2</SUB> nanofibers (NFs) were prepared as an effective photodegradation of three azo dyes as well as an antimicrobial agent under visible light. Fabrication of one dimensional zero-valent Cu nanoparticles-doped TiO<SUB>2</SUB> nanofibers with high aspect ratio have been successfully synthesized by simple and low cost; electrospinning technique followed by hydrothermal process. The photocatalytic activity of introduced nanofibers was evaluated by performing of three azo dyes. Catalytic NFs show a superior photodegaradation activity under visible light as well as good antimicrobial activity. Moreover, photocatalyst nanofibers appeared good stability, which was used for three cycles without regeneration.

Catalytic hydrolysis of ammonia borane for hydrogen generation using Cu(0) nanoparticles supported on TiO₂ nanofibers

Yousef, Ayman,Barakat, Nasser A.M.,EL-Newehy, Mohamed H.,Ahmed, M.M.,Kim, Hak Yong Elsevier 2015 Colloids and surfaces. A, Physicochemical and engi Vol.470 No.-

<P><B>Abstract</B></P> <P>Cu(0) nanoparticles supported on TiO<SUB>2</SUB> nanofibers (Cu-decorated TiO<SUB>2</SUB> NFs) are introduced as an effective photocatalyst for hydrolytic dehydrogenation of ammonia borane (AB) under solar radiation. The introduced Cu-decorated TiO<SUB>2</SUB> NFs were prepared using electrospinning followed by hydrothermal treatment as a novel route for preparation of metal-decorated metal oxide nanofibers. Interestingly, the utilized physicochemical characterizations showed that the prepared nanocatalyst composed of core TiO<SUB>2</SUB> NFs decorated by Cu(0) NPs. A strong photocatalytic activity for catalytic hydrolysis of AB under solar radiation using the introduced nanocatalysts was observed. The results reveal that high rate of hydrogen release from ammonia borane (2.75 equivalent moles) as compared to undecorated TiO<SUB>2</SUB> NFs (1.6 equivalent moles) and pristine Cu NPs (1.2 equivalent moles). The obtained high hydrogen production, in case of the introduced Cu-decorated TiO<SUB>2</SUB> NFs, is attributed to the dual effect of counter parts. Furthermore, the introduced nanofibers could be utilized for three successive cycles with the same efficiency which reflects high stability. Moreover, the photocatalytic activity of the introduced NFs was further confirmed by photodegradation of methylene blue (MB) under solar radiation; complete removal was observed after 120min.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Cu(0) nanoparticles covered surface of titanium dioxide nanofibers. </LI> <LI> High catalytic activity in hydrogen release from ammonia borane. </LI> <LI> Prepared photocatalyst can be reused with the same activity. </LI> </UL> </P>