Dielectric relaxation of chlorinated polyvinyl chloride (CPVC) stabilized with cyanoguanidine

Salah Mahrous,Taha A. Hanfy,Maged S. Sobhyv 한국물리학회 2007 Current Applied Physics Vol.7 No.6

Dielectric spectra of CPVC stabilized with cyanoguanidine were studied in the temperature range 300450 K and frequency range10 kHz to 1 MHz. In these conditions, only one clear dielectric relaxation band (a-type) associated with dipolar polarization wasobserved. Dielectric losses was found to directly proportional to the number of dipoles (N) which reects the orientational distributionof polymer chains in the amorphous region, at which dielectric losses concerned. Calculations of the dielectric modulusM0(T) at lowtemperature indicate that there is a role of the electrode polarization in the relaxation process. Dielectric loss data were used to calculatethe activation enthalpy by two dierent methods, the obtained value was. 450 kJ/mol.

Performance of pillar design in underground stone mines that include discontinuities

Hyung-Sik Yang,Won-Beom Kim,Mahrous A.M. Ali 한국자원공학회 2012 Geosystem engineering Vol.15 No.3

This paper describes a pillar design methodology that was developed from a study of pillar performance in operating stone mines. A number of methodologies have been developed to calculate full-scale mine pillar strengths based on laboratory scale strength obtained from specimens. Data were collected on rock mass quality, pillar conditions, mining dimensions and intact rock strength. Results showed that current mining practices have resulted in generally stable pillar layouts, without recent cases of extensive pillar collapses; however, failure of the pillars was found to be related to spalling of hard brittle rock, shearing along pre-existing angular discontinuities or progressive extrusion of soft infill material on bedding planes. A numerical model (FLAC3D) for the entire rock mass has been developed in order to analyze the stability of the entire underground opening. A preliminary monitoring phase has been realized, aimed at controlling abandoned rock structure movement at the most significant discontinuities. Some measurements of the vertical stress in the pillars and in the walls have also been performed and were used for model calibration. Once the model has been calibrated, analysis of the actual stress and deformation conditions can then be evaluated, the stability condition of the entire structure can be computed and a forecast analysis of what intervention could be realized to guarantee underground public access can be performed. The developed strength equation can be used to design stable pillar layouts, keeping in mind that the safety factor is greater than 1.5 and the width:height ratio of the pillars is between 0.6 and 0.8. It is concluded that, by applying the developed equation and selecting appropriate input parameters, it should then be possible to calculate the factor of safety.

Biochemical and histopathological studies of sulfonylurea derivative as a new chemotherapeutic agent against liver cancer in free‑ and nano‑coated forms

Sroor Farid M.,Basyouni Wahid M.,Aly Hanan F.,Younis Eman A.,Mahrous Karima F.,Haroun Ahmed A. 한국응용생명화학회 2022 Applied Biological Chemistry (Appl Biol Chem) Vol.65 No.6

The most frequent type of primary liver cancer is hepatocellular carcinoma (HCC), accounting for approximately 90% of primary liver cancers and a third leading cause of cancer deaths. In the current study, the synthesized compound 3 was re-formulated using tetraethyl orthosilicate (TEOS) with weight ratio (1:1) via sol-gel technique. The prepared material has been examined using Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray elemental analysis (EDX), and scanning and transmission electron microscopes (SEM and TEM). Herein, we investigate the mode of action of 3 as potent anti-liver cancer in vivo as normal and nano-forms. Rats were given a single dosage of 50 mg/kg b.wt. of HCC through an intraperitoneal injection (ip). A single dosage of CCl4 (2 ml/kg IP) was also given to rats 2 weeks later. Several liver, tumor and oxidative stress biomarkers were detected including liver enzymes; alanine and aspartate aminotransferases (ALT and AST), alkaline phosphatse (ALP), gamma glutamyl transferase (GGT), glutathione (GSH), lipid peroxide (MDA), catalase (CAT), superoxide dismutase (SOD), total antioxidant capacity (TAC), α-fetoprotein and α-L-Fucosidase. Hepatic pathological pictures were also performed for the documentation of the presence of HCC and supported the biochemical results. Moreover, the DNA damage in liver tissues of male rats using comet assay was studied. The results showed that the HePG2 (− ve) group of rats exhibited a significant reduction (P < 0.05) in DNA damage values (9.30 ± 0.89) relative to other treatment groups. Nevertheless, the DNA damage values in the HePG2 (+ ve) and 5-flurouracil groups were significantly higher (P < 0.01) compared to the HePG2 (− ve) group. Additionally, HePG2 (coated 3) and HePG2 (3) groups exhibited significant decrease in the DNA damage compared to those in HePG2 (+ ve) group.

PWM Control Techniques for Single-Phase Multilevel Inverter Based Controlled DC Cells

Mahmoud A. Sayed,Mahrous Ahmed,Maha G. Elsheikh,Mohamed Orabi 전력전자학회 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.2

This paper presents a single-phase five-level inverter controlled by two novel pulse width modulation (PWM) switching techniques. The proposed PWM techniques are designed based on minimum switching power loss and minimum total harmonic distortion (THD). In a single-phase five-level inverter employing six switches, the first proposed PWM technique requires four switches to operate at switching frequency and two other switches to operate at line frequency. The second proposed PWM technique requires only two switches to operate at switching frequency and the rest of the switches to operate at line frequency. Compared with conventional PWM techniques for single-phase five-level inverters, the proposed PWM techniques offer high efficiency and low harmonic components in the output voltage. The validity of the proposed PWM switching techniques in controlling single-phase five-level inverters to regulate load voltage is verified experimentally using a 100 V, 500 W laboratory prototype controlled by dspace 1103.

PWM Control Techniques for Single-Phase Multilevel Inverter Based Controlled DC Cells

Sayed, Mahmoud A.,Ahmed, Mahrous,Elsheikh, Maha G.,Orabi, Mohamed The Korean Institute of Power Electronics 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.2

This paper presents a single-phase five-level inverter controlled by two novel pulse width modulation (PWM) switching techniques. The proposed PWM techniques are designed based on minimum switching power loss and minimum total harmonic distortion (THD). In a single-phase five-level inverter employing six switches, the first proposed PWM technique requires four switches to operate at switching frequency and two other switches to operate at line frequency. The second proposed PWM technique requires only two switches to operate at switching frequency and the rest of the switches to operate at line frequency. Compared with conventional PWM techniques for single-phase five-level inverters, the proposed PWM techniques offer high efficiency and low harmonic components in the output voltage. The validity of the proposed PWM switching techniques in controlling single-phase five-level inverters to regulate load voltage is verified experimentally using a 100 V, 500 W laboratory prototype controlled by dspace 1103.

쿠웨이트에서의 도시고형폐기물매립지 관리

( Al-meshan A. Meshal ),( Farhat Mahrous ) 한국폐기물자원순환학회 2002 APLAS Vol.2002 No.2

쿠웨이트는 Arabian Gulf의 북서쪽에 자리잡은 면적 18000km²의 인구 2백만이상, 연 증가율 4.7%의 국가이다. 쿠웨이트에서 발생하는 고형폐기물의 총 질량은 2000년에 4백만톤 이상으로 산출할 수 있다. 현재, 여러 거주지역에서 가정 폐기물이 연간 약 1백만톤(총량의 25%) 발생한다. 쿠웨이트에서 일반적으로 시행되고 있는 주요 처분 시스템은 투기이다. 쿠웨이트는 현재, 많은 지역에 19개 이상의 사용 중이거나 오래 되어 중지된 매립지가 있다. 이러한 지역의 기후적인 조건은 높은 온도와 낮은 강우, 높은 증발에 의한 전형적인 건조 기후의 특징을 보인다. 평균 연간 강수량은 대략 100mm정도로 강우에 의해 발생한다. 한편, 평균 연간 증발 비율은 대략 3,800mm이다. 연중 대부분의 온도범위는 20□~50□이다. 본 연구는 쿠웨이트의 온도 조건하에서 매립지의 운영을 제시한다. The State of Kuwait is located at the northwestern comer of the Arabian Gulf and occupies an area of about 18,000 km² with a population of over 2 millions and an annual growth rate of 4.7%. The total quantities of the solid waste generated in the State of Kuwait are estimated in the year 2000 over 4 millions tons. Currently, about 1 million tons per year (representing 25% of the total) are household waste generated by various residential areas. The main disposal system commonly used in Kuwait is dumping sites. Kuwait currently has over 19 active and old closed landfills, which occupy many areas. The climatic conditions of the areas are typical for arid climates characterized by high temperatures and low rainfall and high evaporation. The mean annual precipitation is approximately 100 millimeters occurring as rainfall. On the other hand, the mean annual evaporation rate is approximately 3,800 millimeters. The temperature ranges between 20 and 50℃ most of the year. This paper presents the operation of landfills under extreme climate conditions in the State of Kuwait.

Analysis of FHIT Gene Methylation in Egyptian Breast Cancer Women: Association with Clinicopathological Features

Zaki, Seham Mahrous,Abdel-Azeez, Hala A.,El Nagar, Mona Roshdy,Metwally, Khaled Abdel-Aziz,Ahmed, Marwa M. Samir S. Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.3

Background: Fragile histidine triad (FHIT) gene is a tumor suppressor gene which involved in breast cancer pathogenesis. Epigenetics alterations in FHIT contributes to tumorigenesis of breast cancer. Objective: Our objective was to study FHIT promoter region hypermethylation in Egyptian breast cancer patients and its association with clinicopathological features. Materials and Methods: Methylation-specific polymerase chain reaction was performed to study the hypermethylation of FHIT promoter region in 20 benign breast tissues and 30 breast cancer tissues. Results: The frequency of hypermethylation of FHIT promoter region was significantly increased in breast cancer patients compared to bengin breast disease patients. The Odd's ratio (95%CI) of development of breast cancer in individuals with FHIT promoter hypermethylation (MM) was 11.0 (1.22-250.8). There were also significant associations between FHIT promoter hypermethylation and estrogen, progesterone receptors negativity, tumor stage and nodal involvment in breast cancer pateints. Conclusions: Our results support an association between FHIT promotor hypermethylation and development of breast cancer in Egyptian breast cancer patients. FHIT promoter hypermethylation is associated with some poor prognostic features of breast cancer.

MANAGEMENT OF MUNICIPAL SOLID WASTE LANDFILLS IN THE STATE OF KUWAIT

( Al-meshan A. Meshal ),( Farhat Mahrous ) 한국폐기물자원순환학회 2002 APLAS Vol.2002 No.1

The State of Kuwait is located at the northwestern comer of the Arabian Gulf and occupies an area of about 18,000 km² with a population of over 2 millions and an annual growth rate of 4.7%. The total quantities of the solid waste generated in the State of Kuwait are estimated in the year 2000 over 4 millions tons. Currently, about 1 million tons per year (representing 25% of the total) are household waste generated by various residential areas. The main disposal system commonly used in Kuwait is dumping sites. Kuwait currently has over 19 active and old closed landfills, which occupy many areas. The climatic conditions of the areas are typical for arid climates characterized by high temperatures and low rainfall and high evaporation. The mean annual precipitation is approximately 100 millimeters occurring as rainfall. On the other hand, the mean annual evaporation rate is approximately 3,800 millimeters. The temperature ranges between 20 and 50℃ most of the year. This paper presents the operation of landfills under extreme climate conditions in the State of Kuwait.

Ionospheric disturbance dynamo associated to a coronal hole: Case study of 5-10 April 2010 : disturbance dynamo and coronal hole

Fathy, I.,Amory-Mazaudier, C.,Fathy, A.,Mahrous, A. M.,Yumoto, K.,Ghamry, E. American Geophysical Union 2014 JOURNAL OF GEOPHYSICAL RESEARCH. SPACE PHYSICS Vol.119 No.5

In this paper we study the planetary magnetic disturbance during the magnetic storm occurring on 5 April 2010 associated with high-speed solar wind stream due to a coronal hole following a coronal mass ejection. We separate the magnetic disturbance associated to the ionospheric disturbance dynamo (Ddyn) from the magnetic disturbance associated to the prompt penetration of magnetospheric electric field (DP2). This event exhibits different responses of ionospheric disturbance dynamo in the different longitude sectors (European-African, Asian, and American). The strongest effect is observed in the European-African sector. The Ddyn disturbance reduces the amplitude of the daytime H component at low latitudes during four consecutive days in agreement with the Blanc and Richmond's model of ionospheric disturbance dynamo. The amplitude of Ddyn decreased with time during the 4days. We discuss its diverse worldwide effects. The observed signature of magnetic disturbance process in specific longitude sector is strongly dependent on which Earth's side faces the magnetic storms (i.e., there is a different response depending on which longitude sector is at noon when the SSC hits). Finally, we determined an average period of 22h for Ddyn using wavelet analysis.

The key challenges towards the effective implementation of digital transformation in the mining industry

Abdellah Wael R.,Kim Jong-Gwan,Hassan Mohamed M.A.,Ali Mahrous A. M. 한국자원공학회 2022 Geosystem engineering Vol.25 No.2

Digital transformation (DT) is defined as a strategy for boosting mining assets by attempting significant changes to of own properties through the integration of communication, data computing, and property technologies. Making large-scale changes will be difficult with digital technology, especially if the business is not well-positioned to do so. Increasing cybersecurity protection levels is the most effective way to ensure the success of the transformation. When making significant changes, a clear digital vision should be outlined and implemented with strong leadership. However, the majority of digital transformation initiatives fail before they are completed. The problem does not just affect the mining industry. The purpose of this paper is to investigate the major challenges encountered in digital transformation projects and to propose a strategic solution for implementing and scaling digital initiatives.