566 research outputs found

    The use of beta-carotene as environmentally safe inhibitor for Cu-Al-Ni alloyscorrosion in sulfide polluted chloride solutions

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    The stability of Cu-Al-Ni alloys used in the manufacture of NaCl in Egypt was investigated in sulfide polluted chloride solutions. Three different alloys, namely, Cu-10Al-5Ni, Cu-10Al-10Ni and Cu-10Al-45Niwereinvestigatedinchloride containingsulfide-ions using different electrochemical techniques including polarization and electrochemical impedance spectroscopy. The presence of sulfide ions in the chloride solution accelerates thecorrosion of Cu-Al-Ni alloys,whereas the increase of the nickel content in the alloy improves its corrosion resistance.?-carotene as eco-friendly corrosion inhibitor was used to protect the Cu-10Al-Ni alloys from corrosion in presence of sulfide ions. The corrosion inhibition efficiency reached >95% at 50 ppm of ?-carotene. The alloy surface was investigated by the scanning electron microscope and the surface constituents were analyzed by EDAX. Keywords: Corrosion; chloride, Cu-Ni alloys; EIS; sulfide pollution

    Constructing an Instrument for Measuring the Selective Visual Attention of Basic-Stage Students in Gaza and Verifying its Psychometric Characteristics

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    The research aims at constructing an instrument for measuring the selective visual attention of basic education students in Gaza, and verifying its validity and reliability. The research sample consisted of 200   grade ten students in Khan Younis (for the academic year, 2018 -2019). The evidence of constructive validity and the factorial validity of the instrument were  investigated. Results of the predictive factorial analysis showed that the three tasks of the instrument  covered a single  potential factor  namely selective visual attention. All slides of the selective visual attention tasks have achieved statistically significant correlations with the overall scores of the instrument.  The content of the slides was also validated in relation to the instrument. The instrument reliability was also checked with the alpha coefficient for the final form of the instrument as a whole (0,962), and the split–half  reliability coefficients ranged from (0.770 – 0.907). The final form of the instrument  showed three major functions

    Stability of Some Copper Ternary Alloys in Chloride Solutions Polluted by Sulfide Ions

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    The electrochemical performance of three copper alloys was investigated in simulated marine solution polluted by sulfide ions. Polarization techniques and electrochemical impedance spectroscopy, EIS, were used. Surface examination and morphological studies were employed. The results showed that the Cu-10Ni-10Zn alloy is more stable than the other two alloys. The alloy surface was covered by a barrier layer protecting it from corrosion. The thickness and resistance of the barrier layer formed on the Cu-10Ni-10Zn alloy increases with the increase of the immersion time. The mechanism of the corrosion process and the barrier film formation was discussed.  A comparison was made between the electrochemical stability of the three alloys in sulfide polluted chloride solution. The incorporation of Ni in the Cu2O barrier film leads to its stabilization and the stability is enhanced by the presence of Zn. The results leads to the recommendation of the Cu-10Ni-10Zn alloy for applications in sulfide polluted marine environments. Keywords:  Copper alloys, EIS, Polarization, SEM, Passive Films

    Impact Factors on Subcontractor's Cash Flow Management

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    Objective: This study aims to define how to maintain and protect the subcontractor firms' cash flow from economic fluctuation through legally sustainable solutions. Methods/Analysis: We conducted a case study in the Eastern Delta Region of Egypt. A questionnaire containing a list of 22 impact factors on subcontractors' cash flow was distributed across multiple subcontractor firms with an 82% response rate. It was designed to explore the factors causing cash flow instability and analyze them using SPSS statistics. Findings: The study finds that inflation, late payments, non-compensation for late payments, poor subcontractor cash flow management, subcontractor firms' inclination to avoid disputes, material price fluctuation, and non-compensation terms, as well as suppliers rejection of payment delays, are the most critical factors of subcontractor cash flow problems. Novelty/Improvement:The study suggests adding three sub-articles to Article 57 in "Tender Law" as legally sustainable solutions to protect and maintain the firm's growth rate from inflation, late payment, and the inclination to avoid disputes. Also, the study recommends that the owner ensure that cash is available before procuring the general contractors, as stated in Egyptian Law 182 of 2018. This study will contribute to establishing a sustainable win-win relationship between subcontractors and general contractors. Doi: 10.28991/CEJ-SP2023-09-08 Full Text: PD

    Ultrastructural and Molecular Changes in the Developing Small Intestine of the Toad Bufo regularis

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    The ontogenetic development of the small intestine of the toad Bufo regularis was investigated using twofold approaches, namely, ultrastructural and molecular. The former has been done using transmission electron microscope and utilizing the developmental stages 42, 50, 55, 60, 63, and 66. The most prominent ultrastructural changes were recorded at stage 60 and were more evident at stage 63. These included the appearance of apoptotic bodies/nuclei within the larval epithelium, the presence of macrophages, swollen mitochondria, distorted rough endoplasmic reticulum, chromatin condensation, and irregular nuclear envelop, and the presence of large vacuoles and lysosomes. The molecular investigation involved examining DNA content and fragmentation. The results showed that the DNA content decreased significantly during the metamorphic stages 60 and 63 compared with both larval (50 and 55) and postmetamorphic (66) stages. The metamorphic stages (60 and 63) displayed extensive DNA laddering compared with stages 50, 55, and 66. The percentage of DNA damage was 0.00%, 12.91%, 57.26%, 45.48%, and 4.43% for the developmental stages 50, 55, 60, 63, and 66, respectively. In conclusion, the recorded remodeling of the small intestine represents a model for clarifying the mechanism whereby cell death and proliferation are controlled

    Flexural Behavior of Unbounded Pre-stressed Beams Modified With Carbon Nanotubes under Elevated Temperature

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    Since fire is one of the common reasons for rehabilitation and reconstructions during the service life of a building, it is necessary to assess the elements structural and technical conditions. The objective of the present paper is to investigate the flexural behavior in bending for unbounded full pre-stressed beams with and without the incorporation of carbon nanotubes (CNTs) under the exposure to elevated temperature in comparison with non-pre-stressed beams. The test Method was divided into two major stages where the principal stage’s goal was considering the flexural behavior of fully and non-prestressed concrete beams containing CNT of 0 and 0.04% as cement replacement at ambient temperature. In the second stage, a typical group of beams was prepared and the flexural behavior was explored under the exposure to temperature of 400ºC, for 120 minutes. The major findings upon monitoring the failure mechanisms, ultimate load capacity, and deflection at critical sections, was that the CNT had shown a significant impact on the behavior and extreme resistance of fully and non-prestressed normal concrete. With CNT beams also exhibited higher imperviousness to high-temperature than that of the normal beams. Finally the significant Improvement was that the ultimate load of the non-pre-stressed beam with the presence of the CNT at the lower 50mm in the tension zone showed a gain of 13%, while the ultimate load of the fully pre-stressed beam with the presence of the CNT at the lower 50mm in the tension zone showed a gain of 21% as compared to the same beam without CNT, respectively. For the non-pre-stressed beams, the load capacity of the beam with CNT after exposure had a similar load capacity as the beam without CNT before exposure to high temperature

    Ultrasonographic Diagnosis and Clinical Evaluation of the Foreign Body Complications in the Compound Stomach of Cattle and Buffaloes

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    This study was aimed to detect and record the clinical and ultrasonographic findings of the different complications resulted from the foreign bodies lodged in the compound stomach of cattle and buffaloes. A total of 105 animals (37 cattle and 68 buffaloes) were subjected to study. Based on the clinical and ultrasonographic examination, animals were classified into; acute local reticuloperitonitis (ALRP) (15 cattle and 28 buffaloes), chronic local reticuloperitonitis (CLRP) (6 cattle and 14 buffaloes), acute diffuse reticuloperitonitis (ADRP) (5 cattle and 3buffaloes), reticular abscesses (RA) (4 cattle and 7 buffaloes), traumatic pericarditis (TP) (6 cattle and16 buffaloes) and liver abscess (one cattle). Results revealed that ALRP represented the highest percentage of 40.5% in cattle and 41.2 % in buffalos between the different complications of TRP. TP represented the second complications of higher incidence (16.2% in cows and 23.5% in buffalos). Liver abscess represented the lowest percentage (2.8%) and was recorded in cows only. The pregnant animals were affected more than the non pregnant. Clinical findings represented in systemic reaction and pain tests were commonly encountered in TRP and its complications. Some of the affected animals were negatively respond to metal detector test. Results of the present study indicated that the ultrasonographic examination provide a specific echogenic pattern for the different complications of TRP. It was concluded that, clinical examination only is not efficient to give accurate diagnosis of foreign body lodged in the reticulum and rumen and their complications. Ultrasonography is a safe, non invasive diagnostic confirmatory method that could be used for early detection of such conditions

    Optimization of Reduction Process of Egyptian Ilmenitevia Metallothermic reactions

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    It is important to develop technologies for the production of master alloys for industrial applications. Detailed research on reduction of titanium from Egyptian ilmenite by an aluminothermic process in a graphite Crucible was charged by the mixture of ilmenite, flux, aluminum was investigated. This paper study the effect of aluminum feed (10%- 35%), flux material (type, and amount), and temperature preheat from 50 oC to 400 oC and time of preheating from 0.5 hr. to 3 hrs.  Then, the metallic samples formed by the reduction were analyzed using X-ray diffraction, scanning electron microscopy. The mixed fluxes were strongly and successfully reduced ilmenite to a high-purity master alloy with small amounts of detected impurities. Key words: Aluminothermic, Egyptian ilmenite, flux, ferrotitanium, master alloy DOI: 10.7176/CMR/11-7-04 Publication date:September 30th 2019

    Molecular markers as a prognostic system for hepatocellular carcinoma

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    AbstractThe gene expression profile p16, c-erbB-3 and bcl2 in hepatocellular carcinoma (HCC) patients with and without associated HCV infection, was assessed. Forty-eight subjects were included in the study and divided equally into two groups: HCC with and without HCV associated infection. Adjacent paracancerous tissues were assessed as control samples. Correlations with various clinico-pathological parameters of the tumour were assessed: stage, grade, and tumour size. The c-erbB-3 oncogene was expressed in 83.33% (40/48) of the total HCC sample and in 31.25% (15/48) of the noncancerous lesions. C-erbB-3 was expressed in 87.5% (21/24) of the HCC cases with associated HCV infection and in 79.16% (19/24) of the HCC cases without associated HCV infection. Gene expression of c-erbB-3 was significantly correlated with the clinico-pathological parameters of the tumour. P16 gene expression was found in 12.5% (6/48) of the total HCC sample and in 25% (12/48) of the para-cancerous lesions. P16 was expressed in 12.5% (3/24) of HCC cases with and without associated HCV infection. Gene expression of p16 exhibited significant negative correlation with clinico-pathological parameters of the tumour. Bcl2 gene expression was found in 20.8% (10/48) of the total HCC sample and in the para-cancerous lesions. Bcl2 was expressed in 20.8% (5/24) of the HCC cases with and without HCV associated infection. Gene expression of bcl2 did not show significant correlations with the clinico-pathological parameters of the tumour. In conclusion, gene expression profiles of p16 and c-erbB-3 could be used as prognostic molecular markers in HCC

    Topic Extraction and Interactive Knowledge Graphs for Learning Resources

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    Humanity development through education is an important method of sustainable development. This guarantees community development at present time without any negative effects in the future and also provides prosperity for future generations. E-learning is a natural development of the educational tools in this era and current circumstances. Thanks to the rapid development of computer sciences and telecommunication technologies, this has evolved impressively. In spite of facilitating the educational process, this development has also provided a massive amount of learning resources, which makes the task of searching and extracting useful learning resources difficult. Therefore, new tools need to be advanced to facilitate this development. In this paper we present a new algorithm that has the ability to extract the main topics from textual learning resources, link related resources and generate interactive dynamic knowledge graphs. This algorithm accurately and efficiently accomplishes those tasks no matter how big or small the texts are. We used Wikipedia Miner, TextRank, and Gensim within our algorithm. Our algorithm"s accuracy was evaluated against Gensim, largely improving its accuracy. This could be a step towards strengthening self-learning and supporting the sustainable development of communities, and more broadly of humanity, across different generations.The researcher was partially funded by the Egyptian Ministry of Higher Education and Minia University in the Arab Republic of Egypt. [Joint supervision mission from the fourth year missions (2015–2016) of the seventh five-year plan (2012–2017)]
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