Islamic University of Gaza
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Anaemia among school children aged 6-11 years old in Gaza Strip, Palestine.
No full textThe objective of the study was to determine the prevalence of anaemia among children aged 6-11 old years due to causes other than parasitic infections. The present study was a cross-sectional study that included 1446 school children of both sexes, distributed in three localities ( Khanyounis, Gaza and Beit-lahia of Gaza strip. The cut-off point for anaemia was determined according to the mean of haemoglobin for all studied school age children, which was ( 12 g/dl in accordance to WHO criteria. The observed mean level of Hb was 12 g/dl; standard deviation was 0.915 while the normal value is ranged between 8.9-15.2. Anaemia was found slightly higher in girls ( 36.3% than boys ( 34% . The results showed that anaemia constitute a health problem in Gaza with a prevalence of 35.3%. No variation in the prevalence of anaemia among the three studies areas. It is concluded that anaemia still constitutes a health problem among schoolchildren with a present prevalence among school–age children of 35.3%. It is expected that the prevalence of anaemia may be higher than that reported by this study due to Israeli siege to Gaza Strip.هدفت الدراسة الحالية الى تحديد مستوى شيوع فقر الدم بين أطفال تترواح أعمارهم من بين 6-11 سنة لأسباب غير الاصابة بالأمراض الطفيلية بين هؤالاء الأطفال. اشتملت الدراسة المقطعية الحالية على 1446 طفل من أطفال المدارس من كلا الجنسين وكانوا موزعين على ثلاثة مناطق ( خانيونس, غرب بيت لاهيا في قطاع غزة. تم تحديد مدى الأنيميا ( فقر الدم بين هؤالاء الأطفال بواسطة ايجاد متوسط الهيموغلوبين والذي وصل معدله الى 12 g/dl و هي مشابهة لمعايير منظمة الصحة العالمية. دلت النتائج الحالية على أن معدل شيوع فقر الدم كان 34% بين الأولاد و 36.3% بين البنات مع معدل شيوع عام وصل الى 35.3%. لم تظهر النتائج أي اختلاف في شيوع فقر الدم في المناطق الثلاثة: لا يزال يشكل فقر الدم أحد المشاكل الصحية بين أطفال المدارس بنسبة شيوع 35.3% ويتوقع أن تكون نسبة شيوع الأنيميا أعلى من النسبة التي سجلتها هذه الدراسة نتيجة الحصار الاسرائيلي على قطاع غزة
تعرض عمال محطات الوقود المحتوى على الرصاص في قطاع غزة: مدى الإدراك والأعراض المصاحبة.
No full textAwareness and self reported symptoms among 105 gasoline station workers in the Gaza Strip were assessed. A cross section of workers was asked to fill in a questionnaire. Workers reported high level of knowledge on health effects of leaded gasoline 88 ( 83.8% and lead as an environmental pollutant 89 ( 84.8% . Protective measures were poorly used. Knowledge seems not to have much influence on practice. The most common self reported symptoms were neurological symptoms
including headache 78 ( 74.3% , fatigue 74 ( 70.5% , irritability 66 ( 62.9% , concentration difficulties 65 ( 61.9% , and sleep disturbance 55 ( 52.4% . The prevalence of symptoms increased with increasing years of work ( X2 corrected=7.713,
P=0.021 . Use of respiratory mask in particular can potentially limit such symptoms ( X2 corrected=8.325, P=0.004 .تناولت الدراسة تقييم مدى الإدراك والأعراض المصاحبة الناتجة عن التعرض للوقود المحتوى على الرصاص لدى 105 من عمال محطات الوقود في قطاع غزة. وقد إستخدم الباحثون الاستبانات للحصول على المعلومات. بينت النتائج وجود مستوى عال من المعرفة لدى العمال عن التأثيرات الصحية للوقود المحتوى على الرصاص 88 ( 83.8% وعن الرصاص كملوث للبيئة 89 ( 84.8% . و قد كان استخدام وسائل الحماية ضعيفا وكانت المعرفة لدى العمال ليس لها تأثير كبير على الممارسة، أي على استخدام أدوات الحماية في المحطة، ووجد أن الأعراض الصحية الأآثر شيوعا بين العمال هي الأعراض العصبية وتشمل الصداع 78 ( 74.3% وضعف العضلات 74 ( 70.5% والإثارة العصبية 66
( 62.9% وصعوبات في التركيز 65 ( 61.9% واضطرابات في النوم 55 ( 52.4% ، وكان معدل انتشار الأعراض يزداد بزيادة سنوات العمل في المحطة ( X2 corrected=7.713, P=0.021 وقد تبين أن استعمال قناع التنفس يحد بكفاءة من هذه الأعراض ( X2 corrected=8.325, P=0.004
Influence of sisal fibres and rubber latex on the engineering properties of sand concrete
No full textThis experimental study aims to investigate the properties of sand concrete (SC) by using sisal fibres and latex in various fields in construction. Sisal fibres were applied at four ratios of 0.05%, 0.10%, 0.15% and 0.20%, while liquid latex was replaced with three ratios of 15%, 25% and 35%. In this context, ideal percentages of sisal fibre (0.1% F) and latex (35% L) were combined in a single cement matrix. For each percentage, tests on flow, density, compressive strength, flexural strength, ultrasonic pulse velocity, modulus of elasticity, water accessible porosity, water absorption and shrinkage were performed on fresh and hardened SC. Scanning electron microscopy (SEM) was also conducted for microstructure analysis. Results indicate that adding latex emulsion to SC containing sisal fibres increased the adhesion of the fibres to the cement matrix, which contributed to the increase in flexural strength and the decrease in shrinkage. This condition also helped reduce the porosity and water absorption of latex-modified SC with sisal fibres compared with SC that contained fibres. The improvement occurred in the properties that constitute an obstacle to the widespread use of SC. Thus this improvement has practical implications.This experimental study aims to investigate the properties of sand concrete (SC) by using sisal fibres and latex in various fields in construction. Sisal fibres were applied at four ratios of 0.05%, 0.10%, 0.15% and 0.20%, while liquid latex was replaced with three ratios of 15%, 25% and 35%. In this context, ideal percentages of sisal fibre (0.1% F) and latex (35% L) were combined in a single cement matrix. For each percentage, tests on flow, density, compressive strength, flexural strength, ultrasonic pulse velocity, modulus of elasticity, water accessible porosity, water absorption and shrinkage were performed on fresh and hardened SC. Scanning electron microscopy (SEM) was also conducted for microstructure analysis. Results indicate that adding latex emulsion to SC containing sisal fibres increased the adhesion of the fibres to the cement matrix, which contributed to the increase in flexural strength and the decrease in shrinkage. This condition also helped reduce the porosity and water absorption of latex-modified SC with sisal fibres compared with SC that contained fibres. The improvement occurred in the properties that constitute an obstacle to the widespread use of SC. Thus this improvement has practical implications
Punching shear behaviour of RC flat slabs incorporating recycled coarse aggregates and crumb rubber
No full textThis paper presents experimental, analytical and numerical investigations to evaluate the punching shear strength of concrete slabs incorporating a combination of recycled coarse aggregate (RCA) and crumb rubber (CR). Therefore, twelve different concrete mixes were designed with various substitution ratios of RCA and CR as a partial replacement of natural coarse aggregate (NCA) and fine aggregate (FA), respectively. Four substitution ratios of RCA (0%, 25%, 50% and 100%) by NCA and three substitution ratios of CR (0%, 10% and 20%) by FA were considered. Twelve simply supported two-way RC slabs with dimensions of 1000 × 1000 × 100 mm were cast and tested. The experimental programme was divided into two stages. The first and second stages were respectively conducted to evaluate the mechanical properties and the punching shear behaviour of concrete slabs incorporating a combination of RCA and CR. Experimental results show that the combination of RCA and CR negatively affects the mechanical properties of concrete. The substitution ratios of rubber content had a more significant effect on the reduction of the concrete strengths than the RCA content. The punching shear strength, stiffness and toughness of RC slabs incorporating RCA and CR decreased with increasing CR and RCA contents. Based on the experimental results, a combination of 25% RCA and 10% CR is the optimum substitution ratios that can be used on the concrete mixture, as it has a minor effect on the punching shear strength of concrete slab. The predictions of five approaches, namely ACI 318–2014, ECP 203, Euro −2, BS8110 and CSA A23.3, were compared with the experimental results. Finally, nonlinear element analysis (ANSYS) was conducted to verify the experimental results with numerical ones.This paper presents experimental, analytical and numerical investigations to evaluate the punching shear strength of concrete slabs incorporating a combination of recycled coarse aggregate (RCA) and crumb rubber (CR). Therefore, twelve different concrete mixes were designed with various substitution ratios of RCA and CR as a partial replacement of natural coarse aggregate (NCA) and fine aggregate (FA), respectively. Four substitution ratios of RCA (0%, 25%, 50% and 100%) by NCA and three substitution ratios of CR (0%, 10% and 20%) by FA were considered. Twelve simply supported two-way RC slabs with dimensions of 1000 × 1000 × 100 mm were cast and tested. The experimental programme was divided into two stages. The first and second stages were respectively conducted to evaluate the mechanical properties and the punching shear behaviour of concrete slabs incorporating a combination of RCA and CR. Experimental results show that the combination of RCA and CR negatively affects the mechanical properties of concrete. The substitution ratios of rubber content had a more significant effect on the reduction of the concrete strengths than the RCA content. The punching shear strength, stiffness and toughness of RC slabs incorporating RCA and CR decreased with increasing CR and RCA contents. Based on the experimental results, a combination of 25% RCA and 10% CR is the optimum substitution ratios that can be used on the concrete mixture, as it has a minor effect on the punching shear strength of concrete slab. The predictions of five approaches, namely ACI 318–2014, ECP 203, Euro −2, BS8110 and CSA A23.3, were compared with the experimental results. Finally, nonlinear element analysis (ANSYS) was conducted to verify the experimental results with numerical ones
Health and safety improvement in construction projects: a lean construction approach
No full textObjectives. Lean construction techniques have been considered an effective approach and strategy to reduce accidents in construction projects. This article aims to investigate the application of the lean construction principle and its impact on occupational health and safety. Methods. To achieve the aim, an analytical descriptive method was used. The data were collected through a questionnaire, with 70 respondents who were chosen using a random stratified sample method. The questionnaire evaluated the perception of contractors and consultants about the important lean construction factors and their impact on construction project safety. Results. There is an agreement that the application of lean construction techniques can be impeded by challenges like lack of lean construction knowledge, complexity, misconception about lean construction and difficulties in changing employees. Conclusions. The study identified strategies that could be used to address these challenges that will improve the safety of construction projects. These include enlightenment on benefits of the lean practice, publication of improvements realized from lean practice, training, workers’ involvement and empowerment, persistence, robust planning and gradual implementation.Objectives. Lean construction techniques have been considered an effective approach and strategy to reduce accidents in construction projects. This article aims to investigate the application of the lean construction principle and its impact on occupational health and safety. Methods. To achieve the aim, an analytical descriptive method was used. The data were collected through a questionnaire, with 70 respondents who were chosen using a random stratified sample method. The questionnaire evaluated the perception of contractors and consultants about the important lean construction factors and their impact on construction project safety. Results. There is an agreement that the application of lean construction techniques can be impeded by challenges like lack of lean construction knowledge, complexity, misconception about lean construction and difficulties in changing employees. Conclusions. The study identified strategies that could be used to address these challenges that will improve the safety of construction projects. These include enlightenment on benefits of the lean practice, publication of improvements realized from lean practice, training, workers’ involvement and empowerment, persistence, robust planning and gradual implementation
Experimental and numerical studies on flexural behavior of high strength concrete beams containing waste glass
No full textThe behavior of concrete containing waste glass as a replacement of cement or aggregate was studied previously in the most of researches, but the present investigation focuses on the recycling of waste glass powder as a substitute for silica fume in high strength concrete (HSC). This endeavor deals with the efficiency of using waste glass powder, as an alternative for silica fume, in the flexural capacity of HSC beam. Thirteen members with dimensions of 0.3 m width, 0.15 m depth and 0.9 m span length were utilized in this work. A comparison study was performed considering HSC members and hybrid beams fabricated by HSC and conventional normal concrete (CC). In addition to the experiments on the influence of glass powder on flexural behavior, numerical analysis was implemented using nonlinear finite element approach to simulate the structural performance of the beams. Same constitutive relationships were selected to model the behavior of HSC with waste glass powder or silica fume to show the matching between the modeling outputs for beams made with these powders. The results showed that the loading capacity and ductility index of the HSC beams with waste glass powder demonstrated enhancing ultimate load and ductility compared with those of HSC specimens with silica fume. The study deduced that the recycled waste glass powder is a good alternative to the pozzolanic powder of silica fume.The behavior of concrete containing waste glass as a replacement of cement or aggregate was studied previously in the most of researches, but the present investigation focuses on the recycling of waste glass powder as a substitute for silica fume in high strength concrete (HSC). This endeavor deals with the efficiency of using waste glass powder, as an alternative for silica fume, in the flexural capacity of HSC beam. Thirteen members with dimensions of 0.3 m width, 0.15 m depth and 0.9 m span length were utilized in this work. A comparison study was performed considering HSC members and hybrid beams fabricated by HSC and conventional normal concrete (CC). In addition to the experiments on the influence of glass powder on flexural behavior, numerical analysis was implemented using nonlinear finite element approach to simulate the structural performance of the beams. Same constitutive relationships were selected to model the behavior of HSC with waste glass powder or silica fume to show the matching between the modeling outputs for beams made with these powders. The results showed that the loading capacity and ductility index of the HSC beams with waste glass powder demonstrated enhancing ultimate load and ductility compared with those of HSC specimens with silica fume. The study deduced that the recycled waste glass powder is a good alternative to the pozzolanic powder of silica fume
Influence of substrate roughness and bonding agents on the bond strength between old and new concrete
No full textThis research aims to study factors affecting the strength of adhesion between old concrete and new concrete. Among the factors that have been studied in this research are the type of bonding material and the roughness of the surface adhesion, four types of bonding materials (EPICHOR-1768, C-Latex, SikaBond-T21, EPICHOR-500) have been selected because they are available in local markets. A wire brush is used in order to increase the roughness of sample surfaces. The pull-off and slant shear tests have been adopted to assess the bonding strength between the test the old and new concrete. 30 cylindrical samples (7 cm diameter) have been examined by pull-off test, also slant shear test was conducted on 40 samples (10 cm×10 cm×30 cm). The obtained results showed that there is an active role for the bonding material as well as the surface roughness to increase the strength of adhesion between the old and new concrete. Also, it showed that the best of these bonding materials is EPICHOR-1768 because of its significant impact in increasing the strength of the adhesion between the old and new concrete where the percentage of increase 124% in the pull-off test and 48% in slant shear test, compared to the reference sample for each test. As well, as a result of roughening the surface by brush, the strength of adhesion reaches 4% increase in the pull-off test and 23% in the slant shear test compared with the reference sample for each test, which demonstrates the importance of surface roughness to increase the bonding strength between the old and new concrete.This research aims to study factors affecting the strength of adhesion between old concrete and new concrete. Among the factors that have been studied in this research are the type of bonding material and the roughness of the surface adhesion, four types of bonding materials (EPICHOR-1768, C-Latex, SikaBond-T21, EPICHOR-500) have been selected because they are available in local markets. A wire brush is used in order to increase the roughness of sample surfaces. The pull-off and slant shear tests have been adopted to assess the bonding strength between the test the old and new concrete. 30 cylindrical samples (7 cm diameter) have been examined by pull-off test, also slant shear test was conducted on 40 samples (10 cm×10 cm×30 cm). The obtained results showed that there is an active role for the bonding material as well as the surface roughness to increase the strength of adhesion between the old and new concrete. Also, it showed that the best of these bonding materials is EPICHOR-1768 because of its significant impact in increasing the strength of the adhesion between the old and new concrete where the percentage of increase 124% in the pull-off test and 48% in slant shear test, compared to the reference sample for each test. As well, as a result of roughening the surface by brush, the strength of adhesion reaches 4% increase in the pull-off test and 23% in the slant shear test compared with the reference sample for each test, which demonstrates the importance of surface roughness to increase the bonding strength between the old and new concrete