Published Resarch

Abstract

Zinc phosphate (ZnP) baths are widely used for increasing corrosion resistance and surface preparation for painting. Studies on exploiting these baths in the reinforced concrete (RC) are still in the early stages. This is probably due to the shortcomings, such as the alkaline instability and high porosity of the obtained coatings. Use of natural pozzolan (NP) as cement replacement is growing rapidly due to its economic, ecological, and technical benefits. The combined effect of using ZnP baths and NP-based cement on the resistance of concrete against damage caused by corrosion has been investigated. Four phosphating baths were prepared: ZnP, ZnP-Ni, ZnP-Cu, and ZnP-Mn. Steel specimens were phosphated at 55-60°C for 15 min. Concrete specimens were produced with four different levels of NP: 0% (control), 10 %, 20%, and 30%. The investigation was carried out using RC specimens where a constant anodic potential was impressed after 28 and 90 days of concrete curing. The electrochemical behavior of the coated steel has further been evaluated in chloride contaminated Ca(OH)₂saturated solution (CH-Cl) using the open circuit potential (OCP), the potentiodynamic polarization, and the polarization resistance with time. The bond strength between the coated steel and concrete has been evaluated by the pull-out test. Test results showed that concrete containing NP at higher replacement levels and steel specimens treated in bication baths exhibited corrosion initiation times several times longer than the control concrete with uncoated steel. In addition, the best corrosion performance was noted in the steel specimen treated in the ZnP-Cu bath. Its corrosion density was about twentyfold lower with respect to the bare steel, and its inhibition efficiency exceeded 95% in (CH-Cl) solution. In addition, its polarization resistance was about fifteenfold lower with respect to the bare steel. SEM, EDX, and XRD techniques have been employed, as well.

Key words: Corrosion of reinforcing steel; Natural pozzolan; Zinc phosphate bath; Durability of reinforced concrete.

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https://doi.org/10.1155/2018/9078253

Abstract

Calcined clay was obtained by thermal treatment of the clayey soil used in this study, levels of temperature ranging from (450, 650, 850°C) were studied for 3hours to be stabilized by lime. Pozzolanic activity of thermally treated soil samples, were determined using Chapelle test modified at each level. Combinations of clayey soil, lime and calcined clay selected according to the best result obtained from Chapelle test, were prepared. A constant content of lime (6%), measured as a percent of the dry soil mass was added. while the calcined clay ranged from (0%) to (20%). The experimental parts included compression test in standard proctor mould, Atterberg limits, free swelling and pressure of swelling in oedometer ring, linear shrinkage. the optimum moisture content and maximum dry density were obtained and the test results showed an improvement in consistency properties with a decrease in plasticity index with increase of calcined clay percentage added to the clayey soil. Values of free swelling decreased from (7.4%) to (1.2%), pressure of swelling decreased from (80KPa) to (10KPa) and linear shrinkage decreased from (16.7%) to (2.4%), all of that at the combination 6% lime, 20% calcined clay. that was a clear indicator to the improvement that took place in the clayey soil treated by calcined clay and lime.

Key words: Calcined clay, lime, plasticity index, free swelling, pressure of swelling, linear shrinkage.

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http://magazine.albaath-univ.edu.sy/1/pages/2018/1/07.pdf

Abstract

As E-learning Tools and techniques are becoming more common and compelling, many researches have emerged lately that aims at making it more flexible and applicable. Besides, the content is getting very large nowadays, so that it is very important to develop a more accurate and robust search techniques that help users find the best learning materials that exists all along the web specially on social learning websites.

In this paper we propose a new method to collect, index and retrieve learning materials, a collection algorithm is presented that can bring together content from various sources. We present a semantic indexing method that aims at weighting words of the document based on both DBpedia and Wordnet Ontologies, which proves more accurate results according to the analysis and comparison that are shown in this paper.

Key words: E-learning, DBpedia, WordNet, Search Engine, Social web.

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http://www.jatit.org/volumes/ninetysix12.php

Abstract

The use of traditional medicine is increasing rapidly in many societies due to its efficiency and affordability. Practitioners use locally available herbs and plants to treat illnesses and prepare various herbal wellness tonics and other remedies. Herbal medicines have been proved to be effective in many cases and outperformed chemical drugs.

Subsequently, it becomes essential to develop an herbal repository containing the hierarchical taxonomy that represents the structured knowledge of herbs. Various medical applications can benefit from this repository to ensure the accuracy and the effectiveness of the use of herbs for healing.

Today, medical ontologies have become the most efficient way for representing declarative knowledge about diseases, symptoms, medications, and diagnoses.

Many ontologies have been elaborated in the few past years for some well-known traditional medicines like those identified in China, Africa and Korea. Some of them tried to relate traditional medicine ontologies with known "modern" medical ontologies. Linking traditional medicine ontologies with medical ontologies would promote the use of herbs efficiently.

In this paper, we proposed a new ontology for the herbal medicine. We also introduced an algorithm to align our ontology with the symptom ontology (SYMP) and the disease ontology (DOID). The MeSH ontology is the source of our herbal concepts. We are using this ontology in an educational expert system that prescribes herbs for the treatment of casual symptoms, suggests new herbal blends, and detects the interactions of herbs. We have also developed a simple e-health portal that interacts with the expert system.

Key words: Herbal Medicine, DOID, SYMP, MeSH, Ontology Modeling, Ontology Engineering, Ontologies Alignment, Semantic Technology, Expert Systems.

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https://dx.doi.org/10.6025/jdim/2018/16/3/114-126

Abstract

In this work, we derive analytical solutions for static structure factor for homogeneous and isotropic solution composed of two components interacting with each other via simple van der Waals potential which is inversely proportional to the sixth power of the distance between the two components. We assume that the first component is the solvent and the second component is the dissolved material which has low concentration or density in comparison to the concentration of the solvent, i.e. dilute solution, which is common for macromolecular fluids.

The presented solution is obtained using direct and inverse Fourier transforms in solving Ornstein–Zernike equations (OZE) for multicomponent systems. We calculated isothermal compressibilities as a function of concentration and comparison with other simulation and theoretical results are presented. We believe that the presented solution can be useful in studying biomolecular fluids and other soft matter fluids.

Keywords: Ornstein–Zernike equation; Van der Waals potential; two-component fluid; macromolecular fluid; partial structure factor; isothermal compressibility; soft matter.

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https://doi.org/10.1007/s12043-018-1550-0