Islamic University of Gaza
Institutional Repository of the Islamic University of GazaNot a member yet
10574 research outputs found
Sort by
Occurrence of intestinal parasites of mice Mus musculus in Gaza and Rafah, Gaza Strip, Palestine
No full textTo study the prevalence of intestinal parasites of home mice in Gaza and Rafah, the Gaza strip. This study included the digestive tract of 104 mice; the digestive system was removed after dissection from duodenum to the rectum. Stool samples were taken and saved by preservation SAF. Then the intestine was washed by running water into the sieve and seeing worms were washed with saline solution and then preserved by ethyl alcohol 70%. Stool samples were examined under microscope using saline and iodine using X10 and X40 in the laboratories of the Biology Department. It was found that mice were infected with intestinal parasites with prevalence 48.1% and for coccidia 35.6%. It was possible to identify some species of parasites, especially Giardia and some larvae of the worm and Enterobius. The prevalence of parasites for protozoa was 40.4% and for nematode was 16.3%. It is concluded that mouse is a potential source of intestinal parasites and presence in homes in Gaza strip is highly real risk. Control methods and awareness distribution among Palestinian community should take place, in addition to control mice by conventional traps, and by breeding domestic cats
Occurrence of Gastrointestinal Parasites Among Pre-School Children, Gaza, Palestine
No full textAims: The present study is aimed to asses the occurrence of gastrointestinal parasites among pre-school children in Gaza.
Methods: In this study 679 stool specimens were collected from pre-school children aged <10 months to 60 months attending Ard El-Insan Association ( Community primary health care center in Gaza city. Stool specimens were inspected by a direct smear microscopy and sedimentation techniques.
Results: The present study found that 16.6% of the studied children were infected with intestinal parasites. Infection with Giardia lamblia showed the highest prevalence ( 10.3% among other parasites detected. Intestinal parasite prevalence was higher among male children than females. All age groups were susceptible for parasitic infection and no clear trend due to age.
Conclusions: Intestinal parasites was found also among pre-school children in Gaza and those group of children need more medical attention to avoid them the intestinal parasites consequences.هدفت الدراسة الحالية إلى تقييم حدوث الطفيليات المعوية بين أطفال ما قبل المدرسة فى غزة حيث تم جمع ما مقداره 679 عينة براز من أطفال تتراوح أعمارهم من سن أقل من عشرة أشهر إلى 60 شهر يترددون على جمعية أرض الإنسان ( مركز مجتمعى للرعاية الصحية الأولية فى مدينة غزة. ولقد تم فحص عينات البراز بعدة طرق الأولى هي طريقة المسحة المباشرة والثانية هي تقنية التركيز.
وقد تبين من خلال هذه الدراسة أن ( % 16.6 من أطفال الدراسة كانوا مصابين بالطفيليات المعوية حيث ش َ كل طفيل الجارديا أعلى نسبة انتشار وصلت إلى ( % 10.3 بين الطفيليات المعوية المكتشفة. وقد وجدت الدراسة أن الأطفال الذكور أكثر إصابة بالطفيليات المعوية من الأطفال الإناث. بالإضافة إلى أن كل الفئات العمرية كانت قابلة للإصابة بالطفيليات المعوية وليس هناك اتجاه واضح بالنسبة للإصابة مقارنة بالعمر. توصلت الدراسة أن الطفيليات المعوية موجودة بين أطفال ما قبل المدرسة فى غزة وبينت أيضًا أن هذه المجموعة من أطفال تحتاج انتباه ورعاية طبية
أكثر لتجنبهم مضاعفات الإصابة بالطفيليات المعوية. أوصت الدراسة بتحسين الوضع الصحي بين هؤلاء الأطفال فى غزة لتمكينهم من وجود جسم صحي ونمو طبيعي
Enhancement of optical visible wavelength region selective reflector for photovoltaic cell applications using a ternary photonic crystal
No full text"
In a recent study, the authors proposed an optical broadband angular reflector having a band
selective feature and high reflectivity rate for possible applications in photovoltaic applications
using a binary photonic crystal. The obtained 100% reflectivity regions for TE and TM modes
were in bandwidths of 244 nm and 134 nm, respectively. In this paper, we show theoretically the
enhancement of the omnidirectional total-reflection wavelength range by using a ternary pho-
tonic crystal. By introducing a 30 nm-layer of Si3N4 between every two layers, constituting a
period of the lattice, the regions of 100% reflectivity for TE and TM modes are improved to
bandwidths of 269.641 nm and 155.364 nm, respectively. The improvement in the omnidirectional region is about 16%.""
In a recent study, the authors proposed an optical broadband angular reflector having a band
selective feature and high reflectivity rate for possible applications in photovoltaic applications
using a binary photonic crystal. The obtained 100% reflectivity regions for TE and TM modes
were in bandwidths of 244 nm and 134 nm, respectively. In this paper, we show theoretically the
enhancement of the omnidirectional total-reflection wavelength range by using a ternary pho-
tonic crystal. By introducing a 30 nm-layer of Si3N4 between every two layers, constituting a
period of the lattice, the regions of 100% reflectivity for TE and TM modes are improved to
bandwidths of 269.641 nm and 155.364 nm, respectively. The improvement in the omnidirectional region is about 16%.
Waveguides including negative permeability and simultaneously negative permittivity and permeability materials for sensing applications
No full textIn this paper, a four-layer slab waveguide sensor is proposed. The waveguide has the conventional structure of a substrate, a guiding film and a cladding. At the substrate-film interface, an additional layer is inserted which can be a material with negative permeability or a material with simultaneously negative permittivity and permeability. The proposed waveguide is analyzed and both the dispersion relation and Fresnel coefficients are derived. The reflectance of an incident wave from the structure is investigated and plotted. The reflectance dip appearing in the profile is optimized. Using the two structures as optical sensor is also studied. The حerformance of the two structures as optical sensors is compared.In this paper, a four-layer slab waveguide sensor is proposed. The waveguide has the conventional structure of a substrate, a guiding film and a cladding. At the substrate-film interface, an additional layer is inserted which can be a material with negative permeability or a material with simultaneously negative permittivity and permeability. The proposed waveguide is analyzed and both the dispersion relation and Fresnel coefficients are derived. The reflectance of an incident wave from the structure is investigated and plotted. The reflectance dip appearing in the profile is optimized. Using the two structures as optical sensor is also studied. The حerformance of the two structures as optical sensors is compared
Capacitance-voltage measurements of hetero-layer OLEDs treated by an electric field and thermal annealing
No full text"Abstract: Capacitance-voltage (C-V) characterization of organic light-emitting diodes (OLEDs) having the structure ITO/
PVK (poly (9-Vinylcarbazole)/Rhodamine B dye/Pb is reported. The C-V curves provide more understanding about
processes occurring in OLEDs like the voltages at which holes and electrons start flowing from the two electrodes through
the OLED layers and the voltages at which emission starts. The OLEDs were fabricated under the same annealing conditions
with an additional standard device without annealing for comparison. After depositing the Rhodamine B dye layer on the
PVK thin film, samples were thermally annealed at different temperatures. The Pb layer was then deposited. Some samples
were thermally annealed without applying any field, while others were annealed at the same temperatures under an external
electric field. It was found that devices treated by only thermal annealing and those annealed under an electric field do not
show any light emission whereas the standard device fabricated without any annealing does. The main difference between
devices fabricated by exposure to an electric field while annealing and other devices is the lower turn-on voltages of the
former devices.""Abstract: Capacitance-voltage (C-V) characterization of organic light-emitting diodes (OLEDs) having the structure ITO/
PVK (poly (9-Vinylcarbazole)/Rhodamine B dye/Pb is reported. The C-V curves provide more understanding about
processes occurring in OLEDs like the voltages at which holes and electrons start flowing from the two electrodes through
the OLED layers and the voltages at which emission starts. The OLEDs were fabricated under the same annealing conditions
with an additional standard device without annealing for comparison. After depositing the Rhodamine B dye layer on the
PVK thin film, samples were thermally annealed at different temperatures. The Pb layer was then deposited. Some samples
were thermally annealed without applying any field, while others were annealed at the same temperatures under an external
electric field. It was found that devices treated by only thermal annealing and those annealed under an electric field do not
show any light emission whereas the standard device fabricated without any annealing does. The main difference between
devices fabricated by exposure to an electric field while annealing and other devices is the lower turn-on voltages of the
former devices.
Behavior of geopolymer concrete deep beams containing waste aggregate of glass and limestone as a partial replacement of natural sand
No full textThe geopolymer concrete has outstanding physical properties and positive impact on environment compared to conventional concrete. Present endeavor highlights a strategy for management of glass and limestone waste to recycle them in geopolymer concrete deep beams. In this study, 126 geopolymer concrete samples were made for investigating the mechanical properties of geopolymer concrete with the sand replacement ratio of 0–15% by weight in increments of 5%. In addition, seven Reinforced geopolymer concrete deep beams of 600,150,150 mm were casted with respect to the concrete mix and their performance was examined in four-point bending test as per ASTM C78/C78M considering sand replacing ratio of 0–15%. Moreover, proper material constitutive relationships were selected to simulate the performance of geopolymer concrete incorporating waste aggregate. Consequently, a nonlinear finite element solution in ANSYS 11.0 was developed using these constitutive models to predict the behavior of beams. Experimental observations revealed that the use of waste lime and waste glass aggregates reduced the compressive and tensile strength of geopolymer concrete. Furthermore, the loss in strength using waste glass aggregate was less than 15% when compared to geopolymer concrete with waste limestone. Whereas, 5–15% sand replacing with waste aggregate resulted in an average reduction of 19% in loading capacity of the deep beams. The degradation in the ultimate load of the beams with limestone aggregate was 46.6% lower than that for members containing waste glass aggregate. The strain energy of the deep beams containing waste limestone was enhanced by increasing the waste aggregate content from 5% to 15%. Whilst increasing the ratio of replacement for glass mixes led to a decrease in final compressive strain. The outputs of the numerical analysis, in terms of loading capacity of the geopolymer concrete deep beams, were in good matching with the experimental results.The geopolymer concrete has outstanding physical properties and positive impact on environment compared to conventional concrete. Present endeavor highlights a strategy for management of glass and limestone waste to recycle them in geopolymer concrete deep beams. In this study, 126 geopolymer concrete samples were made for investigating the mechanical properties of geopolymer concrete with the sand replacement ratio of 0–15% by weight in increments of 5%. In addition, seven Reinforced geopolymer concrete deep beams of 600,150,150 mm were casted with respect to the concrete mix and their performance was examined in four-point bending test as per ASTM C78/C78M considering sand replacing ratio of 0–15%. Moreover, proper material constitutive relationships were selected to simulate the performance of geopolymer concrete incorporating waste aggregate. Consequently, a nonlinear finite element solution in ANSYS 11.0 was developed using these constitutive models to predict the behavior of beams. Experimental observations revealed that the use of waste lime and waste glass aggregates reduced the compressive and tensile strength of geopolymer concrete. Furthermore, the loss in strength using waste glass aggregate was less than 15% when compared to geopolymer concrete with waste limestone. Whereas, 5–15% sand replacing with waste aggregate resulted in an average reduction of 19% in loading capacity of the deep beams. The degradation in the ultimate load of the beams with limestone aggregate was 46.6% lower than that for members containing waste glass aggregate. The strain energy of the deep beams containing waste limestone was enhanced by increasing the waste aggregate content from 5% to 15%. Whilst increasing the ratio of replacement for glass mixes led to a decrease in final compressive strain. The outputs of the numerical analysis, in terms of loading capacity of the geopolymer concrete deep beams, were in good matching with the experimental results
نظام شمسي منخفض السعر للمجمدات بدون بطاريات احتياطية
No full textThis paper introduces a 420-liter freezer powered by a PV solar system that works without spare batteries. Hence, it provides a green solution for stand-alone applications in remote areas and in places with electricity shortage. To this end, an AC compressor is replaced with a DC compressor to run by the PV panels using a controller that can allow for easy start-up, maximum power tracking, and power management for the system. The designed prototype enabled the freezer to run with attested operation. There are no issues concerning the compressor starting if the speeds is lowered. The system can remain operational even during low solar irradiance days. In addition, an optimum utilization of the photovoltaic energy can be accomplished.This paper introduces a 420-liter freezer powered by a PV solar system that works without spare batteries. Hence, it provides a green solution for stand-alone applications in remote areas and in places with electricity shortage. To this end, an AC compressor is replaced with a DC compressor to run by the PV panels using a controller that can allow for easy start-up, maximum power tracking, and power management for the system. The designed prototype enabled the freezer to run with attested operation. There are no issues concerning the compressor starting if the speeds is lowered. The system can remain operational even during low solar irradiance days. In addition, an optimum utilization of the photovoltaic energy can be accomplished
Experimental and numerical investigations of the influence of partial replacement of coarse aggregates by plastic waste on the impact load
No full textThe effect of partial replacement of coarse aggregate by plastic waste on the performance of concrete under impact three-point bending loading was investigated experimentally and numerically. Specimens were prepared for 5%, 10% and 20 % replacements by volume of coarse aggregate. For each case, three beams of 100 mm wide, 50 mm deep and 400 mm long were loaded to failure in a drop-weight impact machine by subjecting it to 30 N weight from 400 mm height, while another three beams of the same size were tested under static load. The load-displacement of beams of concrete with plastic waste subjected to static and impact loads were studied. The dynamic beam behaviour was also analysed numerically using the finite-element method (FEM) based LUSAS software. In general, the experimental results reveal that the impact tup, inertial load and bending load increase with the increase in the percentage of coarse aggregate replacement by plastic waste, while the static peak bending load always decreases. The concrete with plastic waste is stronger and more energy-absorbing under impact loading, than under static loading. The predicted load against displacement behaviours of both ordinary concrete and concrete with plastic waste, are well matched with the experimental results.The effect of partial replacement of coarse aggregate by plastic waste on the performance of concrete under impact three-point bending loading was investigated experimentally and numerically. Specimens were prepared for 5%, 10% and 20 % replacements by volume of coarse aggregate. For each case, three beams of 100 mm wide, 50 mm deep and 400 mm long were loaded to failure in a drop-weight impact machine by subjecting it to 30 N weight from 400 mm height, while another three beams of the same size were tested under static load. The load-displacement of beams of concrete with plastic waste subjected to static and impact loads were studied. The dynamic beam behaviour was also analysed numerically using the finite-element method (FEM) based LUSAS software. In general, the experimental results reveal that the impact tup, inertial load and bending load increase with the increase in the percentage of coarse aggregate replacement by plastic waste, while the static peak bending load always decreases. The concrete with plastic waste is stronger and more energy-absorbing under impact loading, than under static loading. The predicted load against displacement behaviours of both ordinary concrete and concrete with plastic waste, are well matched with the experimental results
العلاقة بين كفاءة مدراء المشروعات و اداء العاملين في صناعة التشييد بقطاع غزة
No full text: Projects managers‟ competencies are one of the factors that have the greatest impact on the employees'
performance in construction projects. However, many construction companies appear to give insufficient attention
to the issues related to improving the competencies of their project managers. This study investigated the
relationship between projects managers' competencies and employees' performance under the setting of Gaza
construction firms. It aims to identify the competencies required for the contractor's projects managers that
contribute towards the employees' performance and exploring the most effective methods for developing the
construction project manager competencies. A questionnaire survey was used. A total of 110 structured
questionnaires were distributed targeting project managers, 94 valid questionnaires to be used for further
discussions with a response rate of 85.5%. The results show that the employees' performance in construction
projects is highly affected by the competences of the project manage. It is found that the top three measures of
construction employees' performance according to its influence by the competencies of the project‟s managers are;
„productivity‟, „compliance with work instructions‟ and „working after regular working time‟. Whereas to
influence the employees' performance, the top three most important competencies needed for project manager
were: „communication skills‟, „team management‟ and „problem solving‟. The best methods to develop the project
manager's competencies are „on-the job training‟, „off-the job training‟ and „Observing experienced others‟.تعتبر كفاءات مديري المشاريع من العوامل التي لها التأثير الأكبر على أداء الموظفين في مشاريع البناء. ومع ذلك ، يبدو أن العديد من شركات المقاولات لا تولي اهتماما كافيا للقضايا المتعلقة بتحسين كفاءات مديري مشاريعهم. تناولت هذه الدراسة العلاقة بين كفاءات مديري المشاريع وأداء الموظفين في ظل ظروف شركات البناء في غزة. تهدف هذه الدراسة إلى تحديد الكفاءات المطلوبة لمديري مشاريع المقاول التي تساهم في أداء الموظفين واستكشاف أكثر الطرق فعالية لتطوير كفاءات مدير مشروع البناء. تم استخدام الاستبيانة لجمع المعلومات حيث تم توزيع ما مجموعه 110 استبيانات تستهدف مديري المشاريع ، و تم استرداد 94 استبيانًة صالحًة لاستخدامها في مزيد من المناقشات بمعدل استجابة 85.5٪. أظهرت النتائج أن أداء الموظفين في مشاريع البناء يتأثر بشكل كبير بكفاءات مدير المشروع. لقد وجد أن أعلى ثلاثة مقاييس لأداء العاملين في البناء حسب تأثيرها من قبل كفاءات مديري المشروع هي: "الإنتاجية" ، "الامتثال لتعليمات العمل" و "العمل بعد وقت العمل المعتاد". في حين للتأثير على أداء الموظفين ، كانت أهم ثلاث كفاءات مطلوبة لمدير المشروع هي: "مهارات الاتصال" و "إدارة الفريق" و "حل المشكلات".و يعتبر أفضل الطرق لتطوير كفاءات مدير المشروع هي "التدريب أثناء العمل" و "التدريب خارج العمل" و "مراقبة الآخرين ذوي الخبرة"