Silicon (Si)-based materials are sought in different engineering applications including Civil, Mechanical, Chemical, Materials, Energy and Minerals engineering. Silicon and Silicon dioxide are processed extensively in the industries in granular form, for example to develop durable concrete, shock and fracture resistant materials, biological, optical, mechanical and electronic devices which offer significant advantages over existing technologies. Here we focus on the constitutive behaviour of Si-based granular materials under mechanical shearing. In the recent times, it is widely recognised in the literature that the microscopic origin of shear strength in granular assemblies are associated with their ability to establish anisotropic networks (fabrics) comprising strong-force transmitting inter-particle contacts under shear loading. Strong contacts pertain to the relatively small number of contacts carrying greater than the average normal contact force. However, information on how such fabrics evolve in Si-based assemblies under mechanical loading, and their link to bulk shear strength of such assemblies are scarce in the literature. Using discrete element method (DEM), here we present results on how Si-based granular assemblies develop shear strength and their internal fabric structures under bi-axial quasi-static compression loading. Based on the analysis, a simple constitutive relation is presented for the bulk shear strength of the Si-based assemblies relating with their internal fabric anisotropy of the heavily loaded contacts. These findings could help to develop structure-processing property relations of Si-based materials in future, which originate at the microscale.
The corrosion behavior of low carbon steel in washing water of crude oil solution has been studied potentiostatically at five temperatures in the range (30–70)°C .The corrosion potential shifted to more negative values with increasing temperature and the corrosion current density increased with increasing temperature. Folic acid had on inhibiting effect on the corrosion of low carbon steel in washing water at a concentration (5× 10-4-- 5× 10-3 ) mol/dm3 over the temperature range (30–70)°C. Values of the protection efficiency were calculated from the corrosion current density .From the general results for this study, it can be seen that thermodynamic and kinetic function were also calculated (?G, ?S, ?H and Ea )
... Show MoreThe research aims to identify the effect of using the strategy of Roundhouse on the achievement of fourth-grade students of computer and their Attitudes towards it. The research sample consisted of (61) fourth-grade secondary school students distributed into the experimental group consisted of (31) students study computer according to the Roundhouse strategy, and the control group consisted of (30) students follow the traditional method. The researcher designed an achievement test consisting of (30) items of multiple choice. To measure the attitudes of students towards the computer, a questionnaire of (32) paragraphs with three alternatives was designed by the researcher. The results showed that there is a statistically significant diffe
... Show Moreackground: Escherichia coli is one of the most
important bacterial pathogen that can cause several
disease to human being . In our study we try to
investigate the sensitivity resistance pattern of
Escherichia coli against three antibiotics ( Amikacin,
Nalidixic acid and Cephalexin).
Methods: For this purpose we collected 51 clinical
isolates of Escherichia coli from stool and urine of
outpatient and inpatient patients from different wards
of AL-SADER Teaching Hospital in AL-NAJAF
AL-ASHRAf, IRAQ, and tested by culture and
sensitivity test .
Results: The results appeared that Amikacin show
the highest percentage of sensitivity ( 66.66 % ) ,
while Cephalexin show the lowest percentage of
sensiti
ABSTRACT
A field experiment was carried out in the fields of the college of agricultural engineering sciences, university of Baghdad during the fall season of 2021, in order to find out which of the cultivated genotypes of maize are efficient under nitrogen fertilization. The experiment was applied according to a RCBD (split plot design with three replications). The genotypes of experiment (Baghdad, 5018 and Sarah) and supplying three levels of nitrogen fertilizer, which are N1 (100 kg/ha), N2 (200 kg/ha) and N3 (300 kg/ha), the results of the statistical analysis are showed the superiority of the cultivar Sarah in the trait of number of days until 50% silking, chlorophyll
... Show MoreThis study aims to highlight the role of strategic leadership in adopting the intelligent organization model. The study was conducted on 7 economic organizations in Algeria. The study population consisted of 354 leaders, of whom a random sample of 176 leaders (managers, department heads, division heads, engineers) was selected. The researcher used a questionnaire as the main tool of the study. Statistical analysis and hypothesis testing were conducted using SEM (Structural Equation Modeling) with the aid of SPSS.v26 and AMOS.v24 software. The study concluded with a set of results, most notably: there is a statistically significant direct positive effect between strategic leadership and building intelligent organizations at a significance le
... Show MoreThis research was conducted under Lath house canopy of a nursery circumstances, Baghdad University for season 2013 in order to study the effect of soak lemon seeds sour orange with different levels of licorice concentrations extract (0, 0.5, 2.5 and 4.5 g/l) for 24 hours in the percentage of germination and some recipes vegetative growth of seedlings .the results outweigh the bitter orange seedlings and focus soak for licorice extract 4.5 g / l significant superiority in most of the traits plant height, leaf number, root length, stem diameter, amounting to 31.077 cm, 14.46 paper / plant, 25.35 cm, 0.52 mm respectively, which showed significant differences for the treatment of comparison which gave lower values. Clear that the licorice ext
... Show MoreThe present study aims at identifying the effect of organizational pressure with its aspects (management, work team, nature and conditions of work, external environment) on job performance in all its dimensions (commitment and effort made, capabilities and the rapidity of performance, motivation and job satisfaction, work environment) for the university teacher at the Faculty of Economics, Commercial and Management Sciences at the University of Djelfa, Algeria.
In this research, the descriptive analytical approach is used. Data was collected through the distribution of a questionnaire to a sample that included 130 permanent teachers before being analyzed using the (SPSS) statisti
... Show MoreThe organizational integration forms a necessity according to McKinsey model, especially for service organizations. In the context of various service sector developments, importance adoption of compact mechanisms by these organizations to upgrade their services has increased and senior management must be more aware of environmental, competitive and developmental requirements. It gets more important when it shows in an organization seeking at excellence of making services within its policies and strategies. Subject organizational integration dimensions (strategy, structure, systems, style, staff, shared values, and skills) are effective components in directing behaviors of employees and organization. This motivated both researcher
... Show MoreThe main aim of this study is to investigate the ability of four local entomopathogenic isolates Beauveria bassiana (Bals.) and Metarhizium anisopliae (Met.) to control the mosquito larvae in the lab. The results revealed that the isolate (MARD48) B .bassiana reduced the survival rate of the mosquito larvae to (80%) followed by the isolate M. anisopliae (MARD10) to (90%) in the first two days of treatment, and 60 and 66% respectively in the third day. The results also showed that the isolate B. bassiana (MARD48) killed 50% of the population (LC50) with the concentration 1×104 conidia/ml compared to 1×107 conidia/ml for the isolates B. bassiana (MARD14) and M. anisopliae (MARD10), and 1×108 conidia/ml for the isolate B .bassiana (MARD76).
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