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معرفة عوامل خطر الإصابة بسرطان عنق الرحم لدي النساء الفلسطينيات: دراسة مقطعية وطنية
No full text"Background: High awareness of cervical cancer (CC) risk factors is important to decrease the morbidity and mortality associated with CC. This study aimed to assess the knowledge level of Palestinian women about CC risk factors and to determine the factors associated with good knowledge.
Methods: This was a national cross-sectional study. Adult women from hospitals, primary healthcare centers, and public spaces of 11 governorates in Palestine were recruited using a stratified convenience sampling. A translated-into-Arabic version of the validated CC awareness measure (CeCAM) was used to assess the knowledge about the 11 CC risk factors. For each correctly identified risk factor, the participant was given one point. The total score was calculated and was categorized into three categories: poor knowledge (0–3), fair knowledge (4–7), and good knowledge
(8–11).
Results: A total of 7223 participants completed the Arabic CeCAM (response rate = 89.3%) and 7058 questionnaires were included in the final analysis: 2655 from the Gaza Strip and 4403 from the West Bank and Jerusalem. Participants recruited from the Gaza Strip were younger, getting lower monthly incomes, and with less chronic diseases than participants recruited from the West Bank and Jerusalem. The most frequently identified risk factor was ‘having a weakened immune system’ (n = 5458, 77.3%) followed by ‘infection with a sexually transmitted infection’ (n = 5388, 76.3%). The least identified risk factor was ‘having many children’ (n = 1597, 22.6%). Only 1670 women (23.7%) had good knowledge of CC risk factors. Women living in the Gaza Strip were more likely than women living in the West Bank and Jerusalem to have good knowledge (25.2% vs 22.7%). Completing a secondary or diploma degree, being employed, and having a monthly income of ≥ 1450 NIS (around $450) were all associated with lower likelihood of having good knowledge of CC risk factors. Conversely, knowing someone with cancer was associated with higher likelihood of having good knowledge.
Conclusion: The overall awareness of CC risk factors was low. There is a substantial need to establish educational programs to promote Palestinian women’s awareness of CC.""خلفية البحث: الوعي العالي بعوامل الخطر لسرطان عنق الرحم مهم لتقليل نسبة المرض والوفيات المرتبطة بسرطان عنق الرحم. هدفت هذه الدراسة إلى تقييم مستوى معرفة النساء الفلسطينيات حول عوامل خطر الإصابة بسرطان عنق الرحم وتحديد العوامل المرتبطة بالمعرفة الجيدة.
منهجية البحث: كانت هذه دراسة مقطعية وطنية. تم اختيار المشاركات في هذا البحث من النساء البالغات و تم جمع البيانات من النساء من المستشفيات ومراكز الرعاية الصحية الأولية والأماكن العامة في 11 محافظة في فلسطين باستخدام عينة ملائمة طبقية. تم استخدام نسخة مترجمة إلى العربية من مقياس الوعي لسرطان عنق الرحم (CeCAM) لتقييم المعرفة حول عوامل الخطر ذات العلاقة بسرطان عنق الرحم. لكل عامل خطر تم تحديده بشكل صحيح ، تم إعطاء المشارك نقطة واحدة. تم حساب النتيجة الإجمالية وتم تصنيفها إلى ثلاث فئات: ضعف المعرفة (0-3) ، ومتوسطة (4-7) ، والمعرفة الجيدة (8-11).
النتائج: أكمل ما مجموعه 7223 مشاركًا اختبار CeCAM باللغة العربية (معدل الاستجابة = 89.3٪) وتم تضمين 7058 استبيانًا في التحليل النهائي: 2655 من قطاع غزة و 4403 من الضفة الغربية والقدس. كان المشاركون من قطاع غزة أصغر سناً, ويحصلون على دخل شهري أقل ، ولديهم أمراض مزمنة أقل من المشاركين من الضفة الغربية والقدس. كان عامل الخطر الأكثر تحديدًا هو ""ضعف الجهاز المناعي"" (العدد = 5458 ، 77.3٪) متبوعًا بـ ""الإصابة بعدوى تنتقل عن طريق الاتصال الجنسي"" (العدد = 5388 ، 76.3٪). كان عامل الخطر الأقل تحديدًا هو ""إنجاب العديد من الأطفال"" (العدد = 1597 ، 22.6٪). فقط 1670 امرأة (23.7٪) لديهن معرفة جيدة بعوامل خطر الإصابة بالسكري. كانت النساء اللواتي يعشن في قطاع غزة أكثر عرضة من النساء في الضفة الغربية والقدس للحصول على معرفة جيدة (25.2٪ مقابل 22.7٪). إن إكمال الشهادة الثانوية أو الدبلوم ، والتوظيف ، والحصول على دخل شهري قدره 1450 شيكل إسرائيلي جديد (حوالي 450 دولارًا) ، كلها مرتبطة بانخفاض احتمالية امتلاك معرفة جيدة بعوامل خطر الإصابة بسرطان عنق الرحم. على العكس من ذلك ، ارتبطت معرفة شخص مصاب بالسرطان بارتفاع احتمالية امتلاك معرفة جيدة.
الخلاصة: كان الوعي العام لعوامل الخطر ذات العلاقة بسرطان عنق الرحم منخفض. هناك حاجة جوهرية لإنشاء برامج تثقيفية لتعزيز وعي النساء الفلسطينيات ببرنامج سرطان عنق الرحم.
تقييم الوعي وممارسات النظافة الشخصية فيما يتعلق بـ COVID-19 بين البالغين في غزة ، فلسطين
No full textCoronavirus disease 2019 (COVID-19) has spread worldwide and become an emerging life-threatening pandemic disease since 2019. This study aimed to evaluate the basic knowledge, awareness, personal hygiene and healthy practices regarding COVID-19 during its outbreak among the Palestinian population in the Gaza Strip. It is a cross-sectional survey carried out between July and August 2020 and included 458 participants, aged 18 years or older, belonging to the five Gaza Strip governorates, Palestine, with a variety of socio-economic status. Sociodemographic data and data on COVID-19 knowledge, awareness, personal hygiene and healthy practices were collected via email and social media applications (WhatsApp and Facebook) from the study participants. Statistical analyses were performed using Vr 22 of the SPSS software. Overall, the mean ± SD age of the participants was 26.5 ± 4.2 years. Our findings showed that most of the Gazan adults had very good knowledge regarding COVID-19 in terms of host sources, causative agents, incubation period, symptoms, transmission, treatment and prevention. Additionally, most of the participants had a high level of personal hygiene and healthy practices during the COVID-19 outbreak, where personal hygiene and healthy practices against COVID-19 was 77.4%. Furthermore, a higher educational level did not affect the quality of personal hygiene and healthy practice behaviours during the COVID-19 outbreak. Although most of the Gazans had good knowledge regarding the healthy practices, a significant percentage of the population did not practice the hygiene protocol. Despite the majority of the Gazan population having very good knowledge regarding COVID-19 and a high level of personal hygiene and healthy practices during the COVID-19 outbreak, a small proportion require education about avoiding physical contact and maintaining social distancing with others during the pandemic.Coronavirus disease 2019 (COVID-19) has spread worldwide and become an emerging life-threatening pandemic disease since 2019. This study aimed to evaluate the basic knowledge, awareness, personal hygiene and healthy practices regarding COVID-19 during its outbreak among the Palestinian population in the Gaza Strip. It is a cross-sectional survey carried out between July and August 2020 and included 458 participants, aged 18 years or older, belonging to the five Gaza Strip governorates, Palestine, with a variety of socio-economic status. Sociodemographic data and data on COVID-19 knowledge, awareness, personal hygiene and healthy practices were collected via email and social media applications (WhatsApp and Facebook) from the study participants. Statistical analyses were performed using Vr 22 of the SPSS software. Overall, the mean ± SD age of the participants was 26.5 ± 4.2 years. Our findings showed that most of the Gazan adults had very good knowledge regarding COVID-19 in terms of host sources, causative agents, incubation period, symptoms, transmission, treatment and prevention. Additionally, most of the participants had a high level of personal hygiene and healthy practices during the COVID-19 outbreak, where personal hygiene and healthy practices against COVID-19 was 77.4%. Furthermore, a higher educational level did not affect the quality of personal hygiene and healthy practice behaviours during the COVID-19 outbreak. Although most of the Gazans had good knowledge regarding the healthy practices, a significant percentage of the population did not practice the hygiene protocol. Despite the majority of the Gazan population having very good knowledge regarding COVID-19 and a high level of personal hygiene and healthy practices during the COVID-19 outbreak, a small proportion require education about avoiding physical contact and maintaining social distancing with others during the pandemic
دراسة تاثيرمركبات الفوسفات العضوي على مزارع الخلايا الليمفاوية
No full textFor many years, organophosphate (OP) pesticides have been considered an attractive
choice for pest control around the world. Excessive use of OPs is a concerning issue
for human health. Although the genotoxic effect of these pesticides has been
reported, studies that examined their aneuploidy-inducing effect are limited or
absent. Therefore, we sought to investigate the potential of OP pesticides, which are
extensively used in the Gaza Strip, to induce aneuploidy in human peripheral blood
lymphocyte (PBL) cultures. To achieve this goal, we first assessed the cytotoxic effect
of selected concentrations of Nemacur (fenamiphos), Rogor (dimethoate), and
Dursban (chlorpyrifos) on human PBL cultures by the MTT assay. Then, fluorescence
in situ hybridization (FISH) technique was used to determine the frequency of
induced aneuploidy (chromosome loss or gain) in human PBL cultures treated with
different concentrations of the three types of OPs. We found that all the OPs treatments
used did not show appreciable cytotoxic effects. Increase in frequencies of
aneuploidy, chromosome loss, and chromosome gain were observed after each treatment
as compared to the results of their respective solvent control cultures, and that
increase of aneuploidy was significantly evident at 0.050 mg/ml of Nemacur. It was
also noticed that chromosome loss is more frequent than chromosome gain for each
concentration of the three types of OPs. While the aneuploidy induction effect of
the investigated OPs is not significant (except for the 0.050 mg/ml of Nemacur),
these pesticides should be examined further since many people are exposed to them.-
العلاقة بين حالة الحديد وفيتامين ب 12مع مرض الشريان التاجي في مدينة غزة
No full textAims: To investigate the association of iron and vitamin B12 status with coronary artery disease in
Gaza city.
Study Design: A Case control study
Place and Duration of Study: Samples were collected from the cardiac unit at Al-Shifa hospital,
Gaza Strip.
Methodology: Case-control study was conducted on a sample of 31 patients with coronary artery
disease (CAD) and 27 apparently healthy controls aged between 30-60 years. Interviewed
questionnaire was conducted among the study population. Vitamin B12, serum ferritin, serum iron,
lipid profile parameters, and high sensitivity C reactive protein were performed. An approval was
acquired from Helsinki ethical committee to perform this study. All data were analyzed by SPSS.
Results: The results showed that the mean level of serum iron in cases (71.6 24.7 µg/dl) was
lower compared to that of controls (87.3 28.4 µg/dl) and the difference was statistically significant
(P=.028). Moreover, transferrin saturation percentage in cases (24.0 ± 8.9%) was lower compared
to controls (29.0 ± 9.9%) and the difference was statistically significant (P=.045). In addition, the mean levels of serum vitamin B12 in cases (238.8 ± 51.4 pg/dl) was lower compared to controls
(337.3± 108.4 pg/dl) and was statistically significant (P<0.001). The Pearson correlation test
showed that there was a significant positive correlation between the level of serum iron with the
level of vitamin B12 among the participants (r = 0.28, P=.032).
Conclusion: The mean differences of transferrin saturation, serum ferritin, and vitamin B12
between cases and controls were statistically significant. The mean levels of serum vitamin B12 in
cases was lower compared to controls and was statistically significant.المقدمة: مرض الشريان التاجي هو تراكم لويحة عصيدية في الشرايين المتوسطة والكبيرة الحجم التي تغذي
ً عضلة القلب. يلعب الحديد دور ً ا رئيسيا في الحفاظ على الوظائف الخلوية المختلفة ويتوسط عمليات الأيض
المختلفة، حيث تؤدي زيادته في الجسم إلى خطر للإصابة بمرض الشريان التاجي عن طريق تعزيز أكسدة
الدهون. يعمل فيتامين ب 12ز تيحفتفي صنيع حامض أميني يسمى ميثونين والذي قد يؤدي نقصه إلى زيادة
تركيز هوموسيستين في البلازما ومن ثم إلى تصلب الشرايين. تساهم معرفة العلاقة بين حالة الحديد وفيتامين
ب و 12مرض الشريان التاجي في تحديد الأولويات ووضع برامج وقاية وطنية فعالة لتقليل معدلات الإصابة
والوفيات الناجمة عن مرض الشريان التاجي.
الهدف: دراسة علاقة حالة الحديد وفيتامين ب 12مع مرض الشريان التاجي في مدينة غزة.
منهجية الدراسة: اعتمدت منهجية الدراسة على استخدام مجموعة تجريبية وأخرى ضابطة وتكونت " "80من
من الأشخاص الذين تتراوح أعمارهم ما بين 30الى 60سنة، بحيث كانت المجموعة المرضية تحتوي على40
شخصاً يعاني من مرض الشريان التاجي، والمجموعة الضابطة تحتوي على 40شخصاً سليماً. تم و تعبئة
استبيانات لكل واحد منهم، وقد تم قياس الفيريتين وفيتا ب مين 12باستخدام تقنية ،ELISAوكذلك تم قياس
مستوى الحديد، الكوليسترول الكلي، الدهون الثلاثية، الكوليسترول الحميد وغير ذلك. تم حساب الكوليسترول
غير المرغوب فيه ومؤشر كتلة الجسم، وقد تم اجراء فحص الدم الشامل، وتم الحصول على موافقة من اللجنة
الأخلاقية المحلية لإجراء هذه الدراسة وتحليل جميع البيانات باستخدام البرنامج الإحصائي المحوسب SPSS
اصدار .22
النتائج: أظهرت النتائج أن هناك فرق ذو دلالة إحصائية بين مستويات الحديد في حالات الذكور كان منخفضا
مقارنه بالذكور في المجموعة الضابطة و . كذلك تبين الدراسة أن هناك فرق ذو دلالة إحصائية بين نسبه تشبع
الترانسفيرين في الحالات الذكور أقل مقارنة بالذكور في المجموعة الضابطة. بالإضافة إلى ذلك، أن متوسط
مستوى فيتامين ب 12في حالات الذكور والذكور في المجموعة الضابطة ذات دلالة إحصائية. من خلال
معامل ارتباط بيرسون تبين أن هناك ارتباطاً إيجابياً كبيراً بين مستوى الحديد مع مستوى فيتامين ب 12بين
الذكور ولكن ليس الإناث.
الاستنتاج: أظهرت هذه الدراسة أن هناك فرقاً ذو دلالة إحصائية في تشبع الترانسفيرين والفيريتين بين الحالات
الذكور والذكور في المجموعة الضابطة. ولم يكن الاختلاف ذا دلالة إحصائية في تشبع الترانسفيرين والفيريتين
ال في حالات الإناث والإناث في المجموعة الضابطة. وكان متوسط مستوى فيتامين ب 12لدى الحالات الذكور
أقل مقارنةً بالذكور في المجموعة الضابطة وكانت ذات دلالة إحصائية. بينما كان متوسط مستوى فيتامين ب
12في الحالات الإناث أقل مقارنةً بالإناث في المجموعة الضابطة ول ، م يكن الاختلاف ذا دلالة إحصائي
استكشاف العلاقات بين خصائص الجودة لنموذج أيزو 9126
No full textConsidering quality attributes when developing software is inevitable. Quality attributes are also known as non-functional requirement that requested by software stakeholders. ISO9126 is one of the best-known quality models that includes some important quality attributes. It is not practical to develop software applications without considering the relationships between quality attributes. This is because that achieving one quality attribute will often enhance or hinder other quality attributes in the software being developed. Many research works have studied the relationships between quality attributes. In this paper we introduced a literature survey for studying and defining the relationships between quality attributes that defined by the ISO9126 quality model. We also proposed a matching mechanism between equivalent attributes that expressed differently in the current published work.يعتبر الأخذ بالحسبان لخصائص الجودة عند تطوير البرمجيات أمرا حتميا. وتعرف خصائص الجودة بالمتطلبات الغير وظيفية والتي يطلبها المهتمون بالبرمجية. يعتبر أيزو 9126 من أكثر نماذج الجودة المعروفة ويشمل عددا من خصائص الجودة. من غير العملي أن يتم تطوير البرمجية بدون الأخد بعير الاعتبار العلاقات بين خصائص الجودة. وذلك لأن انجاز أحد خصائص الجودة غالبا ما يعزز أو يعيق خصائص أخرى في البرمجية المطلوب تطويرها. هناك عدة أبحاث درست العلاقات بين خصائص الجودة. في هذه الورقة قدمنا مسحا أدبيا لدراسة وتعريف العلاقات بين خصائص الجودة المعرفة في نموذج أيزو 9126. واقترحنا أيضا آلية للتوافق بين خصائص الجودة المتكافئة والتي يتم التعبير عنها بطرق مختلفة في الأبحاث المنشورة
A highly birefringent bend-insensitive porous core PCF for endlessly single-mode operation in THz regime: an analysis with core porosity
No full text"We present an endlessly single-mode, bend-insensitive and highly birefringent photonic crystal fbre (PCF) for efcient
wave transmission in the terahertz (THz) spectrum. To facilitate fat dispersion and high birefringence, a diamond-shaped
porous core is introduced inside the Zeonex (background material)-based hexagonal porous cladding. Moreover, the dense
geometrical arrangement of the regular hexagonal lattice in the cladding region holds maximum usable optical power inside
the porous core. The major geometrical parameter of the proposed PCF such as core porosity has been optimized to improve
the optical guiding parameters. The numerically investigated outcomes have shown an ultrahigh birefringence and numerical
aperture of 0.0888 and 0.57, respectively. Apart from this, very low bending and material losses of 3.01 × 10−20 cm−1 and
0.01451 cm−1 with fattened dispersion variation of±0.2463 ps/THz/cm have been achieved over the broad THz band (i.e.
0.8–1.3 THz). Additionally, our proposed PCF sustains endlessly single-mode operation with a very high core power fraction
of 75.28%. With all these promising results, the proposed PCF would be a potential candidate for polarization preserving as
well as for efcient broadband transmission applications in the THz regime.""We present an endlessly single-mode, bend-insensitive and highly birefringent photonic crystal fbre (PCF) for efcient
wave transmission in the terahertz (THz) spectrum. To facilitate fat dispersion and high birefringence, a diamond-shaped
porous core is introduced inside the Zeonex (background material)-based hexagonal porous cladding. Moreover, the dense
geometrical arrangement of the regular hexagonal lattice in the cladding region holds maximum usable optical power inside
the porous core. The major geometrical parameter of the proposed PCF such as core porosity has been optimized to improve
the optical guiding parameters. The numerically investigated outcomes have shown an ultrahigh birefringence and numerical
aperture of 0.0888 and 0.57, respectively. Apart from this, very low bending and material losses of 3.01 × 10−20 cm−1 and
0.01451 cm−1 with fattened dispersion variation of±0.2463 ps/THz/cm have been achieved over the broad THz band (i.e.
0.8–1.3 THz). Additionally, our proposed PCF sustains endlessly single-mode operation with a very high core power fraction
of 75.28%. With all these promising results, the proposed PCF would be a potential candidate for polarization preserving as
well as for efcient broadband transmission applications in the THz regime.
الخلايا الشمسية المعدلة مع طلاء مضاد للانعكاس
No full textDesigning a solar cell that can harvest energy with a high level of efficiency is an important research topic. For improving the performance of solar cells, this paper introduces four proposed structures for solar cells and examines their efficiencies for potential production with low cost and high efficiency. In each model, the absorbent material is Borofloat glass and the antireflection coatings used are SiNx and sol-gel -based materials. The four proposed solar cell structures are as follows: (i) a three-layer solar cell in which a sol-gel film is used to match the refractive index between the glass substrate and air cladding; (ii) a four-layer solar cell in which a sol-gel film is used to match the refractive index between SiNx laid on top of a glass substrate and air cladding; (iii) a four-layer structure in which a sol-gel film topped with air cladding is used as a match between the glass and SiNx; and (iv) a four-layer solar cell in which two layers of SiNx are stacked between the glass and the air. A transfer-matrix method is used to solve for the total transmission and total reflection for all structures, and the effects of the film thicknesses and incidence angles are considered in each case. An analysis is carried out using Maple 17, and the results show that using a sol-gel material between glass and air gives almost zero reflection for a wide range of wavelengths, meaning that this can be used as a perfect absorbent and can therefore be recommended for high- efficiency solar cells. Using two layers of SiNx between the air and glass gives almost zero reflection at 600 nm, making this approach an outstanding candidate for solar cells with a maximum absorption of around 600 nm. The other two structures have lower values of transmission, meaning that they are good candidates for low- efficiency solar cells. However, further techno-economic studies of the proposed structures should be carried out, and that solar cell manufacturers should consider these structures."يعد تصميم خلية شمسية يمكنها حصاد الطاقة بمستوى عالٍ من الكفاءة موضوع بحث مهم. لتحسين أداء الخلايا الشمسية ، تقدم هذه الورقة أربعة هياكل مقترحة للخلايا الشمسية وتفحص كفاءتها من أجل الإنتاج المحتمل بتكلفة منخفضة وكفاءة عالية. في كل نموذج ، تكون المادة الماصة عبارة عن زجاج بوروفلوت والطلاءات المضادة للانعكاس المستخدمة هي SiNx ومواد أساسها هلام سول. الهياكل الأربعة المقترحة للخلايا الشمسية هي كما يلي: (1) خلية شمسية من ثلاث طبقات يتم فيها استخدام فيلم sol-gel لمطابقة معامل الانكسار بين الركيزة الزجاجية والكسوة الهوائية ؛ (2) خلية شمسية من أربع طبقات يتم فيها استخدام غشاء من مادة sol-gel لمطابقة معامل الانكسار بين SiNx الموضوعة فوق طبقة سفلية زجاجية وكسوة هوائية ؛ (3) هيكل من أربع طبقات يتم فيه استخدام غشاء جل-جيل مغطى بطبقة من الهواء كمطابقة بين الزجاج و SiNx ؛ و (4) خلية شمسية من أربع طبقات يتم فيها تكديس طبقتين من SiNx بين الزجاج والهواء. يتم استخدام طريقة مصفوفة النقل لحل الإرسال الكلي والانعكاس الكلي لجميع الهياكل ، ويتم أخذ تأثيرات سماكة الفيلم وزوايا السقوط في الاعتبار في كل حالة. تم إجراء تحليل باستخدام Maple 17 ، وأظهرت النتائج أن استخدام مادة sol-gel بين الزجاج والهواء يعطي انعكاسًا صفريًا تقريبًا لمجموعة كبيرة من الأطوال الموجية ، مما يعني أنه يمكن استخدام هذا كممتص مثالي وبالتالي يمكن التوصية به للخلايا الشمسية عالية الكفاءة. إن استخدام طبقتين من SiNx بين الهواء والزجاج يعطي انعكاسًا صفريًا تقريبًا عند 600 نانومتر ، مما يجعل هذا النهج مرشحًا بارزًا للخلايا الشمسية مع أقصى امتصاص يبلغ حوالي 600 نانومتر. الهيكلان الآخران لهما قيم انتقال أقل ، مما يعني أنهما مرشحان جيدان للخلايا الشمسية منخفضة الكفاءة. ومع ذلك ، ينبغي إجراء مزيد من الدراسات الفنية والاقتصادية للهياكل المقترحة ، ويجب على مصنعي الخلايا الشمسية النظر في هذه الهياكل.
Influence of steam curing regimes on the properties of ultrafine POFA-based high-strength green concrete
No full textThis paper investigated the influence of steam curing regimes on the properties of high-strength green concrete (HSGC) containing varying quantities of ultra-fine palm oil fuel ash (U-POFA) from 0%, 20%, 40% and 60% from the mass of Portland cement. The HSGC specimens were steam cured at 50 °C, 65 °C, and 80 °C for 16 h in order to evaluate the effect of curing temperatures. Besides, the HSGC specimens were also cured at 80 °C for 6, 11 and 16 h in order to investigate the effect of curing period. The influence of different temperatures and periods of steam curing on the development of the compressive strength (CS) and microstructure of the HSGC was investigated at 1, 3, 7, 28, 90, 180 and 360 days. The results showed that replacing 20%, 40% and 60% of ordinary Portland cement (OPC) with U-POFA exhibited a decrease in the CS in early ages up to 7 days, whereas the long-term CS at 360 days improved by 5.4%, 10% and 9.2%, respectively in comparison to the control concrete mixture. It was also found that the application of steam curing regime at 80 °C for 16 h contributed towards increasing the strength of concrete by 193% at 1 day for HSGC containing 60% U-POFA when compared to normally cured specimen. The trends in CS development were complimented with microstructural analyses based on TGA, XRD and SEM/EDX. It was observed that steam curing has a significant influence on microstructures of matrix in early ages. However, it can be concluded that the partial replacement of U-POFA has positive impacts on the long-term properties of the HSGC at 360 days.This paper investigated the influence of steam curing regimes on the properties of high-strength green concrete (HSGC) containing varying quantities of ultra-fine palm oil fuel ash (U-POFA) from 0%, 20%, 40% and 60% from the mass of Portland cement. The HSGC specimens were steam cured at 50 °C, 65 °C, and 80 °C for 16 h in order to evaluate the effect of curing temperatures. Besides, the HSGC specimens were also cured at 80 °C for 6, 11 and 16 h in order to investigate the effect of curing period. The influence of different temperatures and periods of steam curing on the development of the compressive strength (CS) and microstructure of the HSGC was investigated at 1, 3, 7, 28, 90, 180 and 360 days. The results showed that replacing 20%, 40% and 60% of ordinary Portland cement (OPC) with U-POFA exhibited a decrease in the CS in early ages up to 7 days, whereas the long-term CS at 360 days improved by 5.4%, 10% and 9.2%, respectively in comparison to the control concrete mixture. It was also found that the application of steam curing regime at 80 °C for 16 h contributed towards increasing the strength of concrete by 193% at 1 day for HSGC containing 60% U-POFA when compared to normally cured specimen. The trends in CS development were complimented with microstructural analyses based on TGA, XRD and SEM/EDX. It was observed that steam curing has a significant influence on microstructures of matrix in early ages. However, it can be concluded that the partial replacement of U-POFA has positive impacts on the long-term properties of the HSGC at 360 days
Evaluation and optimisation of foam concrete containing ground calcium carbonate and glass fibre (experimental and modelling study)
No full textFoam concretes (FCs) have stronger matrix structure than lightweight concretes. The porosity of foam and lightweight concretes reduces as the density of the material increases. In addition, the porosity of lightweight concrete is highly affected by the aggregates’ pore features, and that of FC is totally affected by the pore structure of the matrix. Addition of ground calcium carbonate (GCC) and glass fibre (GF) to FC was investigated in this study. The effects of ingredients, namely, GCC, GF, cement and water on flexural and compressive strengths and the thermal conductivity properties were also studied. Test results were optimised in a proposed hybrid model. The optimisation results were also validated with laboratory tests. GCC incorporation increases compressive strength and thermal conductivity because of the filling effect. Furthermore, GF inclusion in the concrete mixtures contributes to the flexural strength of concrete.Foam concretes (FCs) have stronger matrix structure than lightweight concretes. The porosity of foam and lightweight concretes reduces as the density of the material increases. In addition, the porosity of lightweight concrete is highly affected by the aggregates’ pore features, and that of FC is totally affected by the pore structure of the matrix. Addition of ground calcium carbonate (GCC) and glass fibre (GF) to FC was investigated in this study. The effects of ingredients, namely, GCC, GF, cement and water on flexural and compressive strengths and the thermal conductivity properties were also studied. Test results were optimised in a proposed hybrid model. The optimisation results were also validated with laboratory tests. GCC incorporation increases compressive strength and thermal conductivity because of the filling effect. Furthermore, GF inclusion in the concrete mixtures contributes to the flexural strength of concrete
Properties and durability of concrete with olive waste ash as a partial cement replacement
No full textThis research aims to study the utilization of olive waste ash (OWA) in the production of concrete as a partial substitute for cement. Effects of using OWA on the physical and mechanical properties of concrete mixtures have been investigated. This is done by carrying out tests involving the addition of various percentages of OWA to cement (0%, 5%, 10% and 15%). For each percentage, tests were performed on both fresh and hardened concrete; these included slump test, unit weight test and compressive strength test after 7, 28 and 90 days. Durability tests were investigated in solutions containing 5% NaOH and MgSO4 by weight of water. In addition, resistance to high temperatures was tested by subjecting the cubes to high temperatures of up to 170oC. The results of this research indicate that a higher percentage of OWA gives a lower compressive strength and lower workability but higher performance in terms of durability against both different weather conditions and high temperatures.This research aims to study the utilization of olive waste ash (OWA) in the production of concrete as a partial substitute for cement. Effects of using OWA on the physical and mechanical properties of concrete mixtures have been investigated. This is done by carrying out tests involving the addition of various percentages of OWA to cement (0%, 5%, 10% and 15%). For each percentage, tests were performed on both fresh and hardened concrete; these included slump test, unit weight test and compressive strength test after 7, 28 and 90 days. Durability tests were investigated in solutions containing 5% NaOH and MgSO4 by weight of water. In addition, resistance to high temperatures was tested by subjecting the cubes to high temperatures of up to 170oC. The results of this research indicate that a higher percentage of OWA gives a lower compressive strength and lower workability but higher performance in terms of durability against both different weather conditions and high temperatures