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Article
Effect of Adding some Additives and Drying Method on Compressive Strength of Gypsum Products

Authors: Wael Abdul Razak وائل عبد الرزاق --- Ihab N. Yassin ايهاب ياسين --- Firas Abd Kati فراس عبد كاطع
Journal: Tikrit Journal for Dental Sciences مجلة تكريت لعلوم طب الاسنان ISSN: 20731213 Year: 2017 Volume: 5 Issue: 2 Pages: 25-32
Publisher: Tikrit University جامعة تكريت

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Abstract

Gypsum products (dental plaster and stone) are widely used indentistry. However, the main problem with any gypsum productsis reproduction of fine details and dimensional stability. Thecurrent study was conducted to assess the effect of incorporatingvarious additives (i.e. cured resin, pulverised stone, pulverisedplaster, and glass fibers) and drying method on compressivestrength of gypsum products. A total of 160 specimens weredivided into 2 groups according to the method of drying (air andmicrowave). For each drying method, each group was subdivideddepending on the type of material used into 2 groups; dentalplaster and dental stone. Variuos additives were used forreinforcement; cured resin, pulverised plaster, pulverised stone,and glass fibers. The unmodified group was considered as control.The specimens were dried and the compressive strength test wasapplied on all specimens. All specimens' data were statisticallyanalysed via ANOVA, Tukey and independent T tests.Thecompressive strength of gypsum products was significantlyinfluenced by the type of additive used. The specimens reinforcedwith glass fibers, cured resin, pulverised plaster, and stone had agreater value of mean compressive strength compared withunmodified groups. Statistically, highly significant differenceswere observed among all dried groups (P≤0.001). As well, themicrowave specimens were more resistant to compressiveloadings than air dried specimens. No significant differences,however, were recorded between the two drying methods(P>0.05).The glass fibers have a significant effect on compressivestrength of gypsum products. The pulverised particles and curedresin can be added at 1 % by weight to enhance the mechanicalproperties of plaster and stone. Microwave drying for 5 minutescan fasten the drying time and permit early manipulation of plasterand stone models.


Article
Effect of different types of saline water on some chemical properties of gypsiferous soil
تأثير انواع مختلفة من المياه المالحة على بعض الصفات الكيميائية للترب الجبسية

Authors: Diaa F. Hassan --- Rafal J. Mohammed --- Ameer A. Jafaar
Journal: Euphrates Journal of Agriculture Science مجلة الفرات للعلوم الزراعية ISSN: 38752072 Year: 2018 Volume: 10 Issue: 3 Pages: 106-113
Publisher: Al-kasim University جامعة القاسم الخضراء

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Abstract

This study selected a soil with a high gypsum content of 590 g.kg-1. Different types of water were used: distilled water, river water and well water. The soil was leached by water at different levels as far as (WHC) Water Holding Capacity. It was leached once and twice and thrice taking into consideration the amount of the field capacity. Then the cations were measure the rate of leaching speed. The rate of leaching of ions for distilled water is higher than that of the river, which is higher than the well water.The effect of leaching was studied with different saline water types and their different quantities In the leaching of saline gypsum Soil salinity was 11.6 ds.m-1 after leaching with the types of water, the salinity were 3.73, 4.95 and 9.01 ds.m-1 for distilled water, river water and Well water respectively, As for the effect of amount of water was found the salainity 7.83, 5.99 and 3.88 ds.m-1 when leaching in three W.H.C, two W.H.C and one W.H.C respectively.Also we show the effect water quality and quantity on gypsum amount so we found that the amount of gypsum were 460, 503.3 and 533.3 g.kg-1 for distilled water, river water and well water respectively. As for the effect the amount of gypsum were 523.3, 500.0 and 473.3 g. kg-1 for one W.H.C, two W.H.C and three W.H.C respectively. As for the speed of leaching the ions it was found that the largest ions be magnesium, followed by calcium and sulfate, then bicarbonate, sodium and chloride, at 0.55, 0.50, 0.50, 0.52, 0.40 and 0.43) meq.l-1 respectively This is due to the bonding of these ions to make salts of different solubility.

شملت الدراسة اختيار تربة ذات محتوى جبسي عالي يبلغ 590 غم.كغم-1 كما استخدمت انواع مختلفة من المياه هي ماء مقطر وماء نهر وماء بئر وقد تم الغسل لهذه التربة بمستويات مختلفة بقدر قابلية التربة العظمى على مسك الماء (W.H.C) اذ غسلت بمقدار مره واحده ومرتين وثلاث مرات مع مراعاة مقدار السعة الحقلية بعد ذلك تم تقدير الايونات لقياس معدل سرعه غسلها اذ يتبين ان معدل سرعة غسل الايونات للماء المقطر اعلى من ماء النهر والذي بدوره اعلى من ماء البئر . تم دراسة تأثير الغسل بنوعيات مياه مختلفة الملوحة وكمياتها المختلفة في غسل ملوحة الترب الجبسية اذ كانت ملوحة التربة الاصلية 11.6 ديسيسيمنز.م-1 اما بعد غسل التربة فقد وجد ان كمية الملوحة انخفضت اذ بلغت 3.75 , 4.95 و 9.01 ديسيسيمنز.م-1 عند الغسل بماء مقطر وماء نهر وبئر على التوالي كما بلغت كمية الملوحة 7.83 , 5.99 و 3.88 ديسيسيمنز.م-1 عند الغسل بمقدار مره واحده ومرتين وثلاث مرات من كمية (W.H.C) . اما كمية الجبس فقد كانت تقل ذوبانياتها مع زيادة ملوخة مياه الغسل اذ كانت كمياتها 460 , 503.3 و 533.3 غم.كغم-1 عند الغسل بماء مقطر وماء نهر وبئر على التوالي كما بلغت كمية الجبس 523.3 , 500 و 473.3 غم.كغم-1 عند الغسل بمقدار مره واحده ومرتين وثلاث مرات من كمية (W.H.C) . اما بالنسبة لسرعة غسل الايون وجد ان اكبر الايونات غسلا هو المغنيسيوم يليه الكالسيوم والكبريتات ثم البيكاربونات بعدها الصوديوم واخرها الكلورايد اذ تم الغسل بمعدلات (0,55 , 0,50 , 0,50 , 0,52 , 0,40 , 0,43 ) مليمكافئ.لتر-1 على التوالي ويعود السبب في هذا الترتيب الى ارتباط هذه الايونات لتكون املاح مختلفة الذوبان .


Article
IMPROVEMENT OF THE MECHANICAL PROPERTIES OF GYPSEOUS SOIL BY ADDITIVES
تحسين الخواص الميكانيكية للتربة الجبسيه بواسطة إضافات

Author: Huda N. T. AL-Numani
Journal: Al-Qadisiyah Journal for Engineering Sciences مجلة القادسية للعلوم الهندسية ISSN: 19984456 Year: 2010 Volume: 3 Issue: 3 Pages: 287-296
Publisher: Al-Qadisiyah University جامعة القادسية

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Abstract

The presence of gypsum in soil as bond agent alters its behavior, in other words, there is a large influence of gypsum on the physical and mechanical properties of soil. This influence depends mainly on the amount and type of gypsum presented in the soil.The soils used in this study were brought from one locations at Al-Tar region west of Al-Najaf city. These soils had gypsum content of 35%. The classification tests indicate that the soil is poorly graded. In this paper an experimental study is carried out on the effect of three different additives to the gypseous soil in order to improve the compaction properties of the gypsum soil. The additives used in this study were cement, ceramic and mix of cement and ceramic. The percentages of ceramic was varied between 4-12% in the first series whereas percentage of cement was between 4-8% by weight in the second series. In the third series the percentage of cement was kept constant 4% by weight while the percentage of ceramic varied from 4 to 12% by weight. Control groub without any additive was also tested to determine the effect of additives. The results show that the best improvement in compaction characteristics test is achieved when the sample is treated with adding mix of cement and ceramic, the maximum dry density only increase with the increases in mixing content, while the opposite is true for the optimum water content. The results also show that the maximum dry density of treated gypsum soil with ceramic material increases with the increase in ceramic content up to 8% after which the density decreases.

وجود الجبس في التربة كعامل ربط يغير سلوكها, بتعبير أخر, هناك تأثير كبير للجبس على الخواص الفيزيائية والميكانيكية للتربة. يعتمد هذا التأثير بشكل رئيسي على كمية ونوع الجبس الموجود في التربة. لتربة المستخدمة في هذه الدراسة أخذت من موقع واحد من منطقة الطار الواقعة غرب مدينة النجف .كانت التربة ذات محتوى جبسي (35%). أشار اختبار التصنيف بأن التربة رمليه ضعيفة التدرج. في هذا البحث أجريت دراسة تجريبية على تأثير ثلاث إضافات مختلفة إلى التربة الجبسيه لكي تحسن خواص الرص للتربة الجبسيه . الإضافات المستعملة في هذه الدراسة هي الخزف , الأسمنت وخليط الأسمنت والخزف. النسب المئوية لمادة الخزف كانت تتفاوت بين (4-12%) في السلسلة الأولى بينما نسبة الأسمنت كانت بين (4-8%) من وزن التربة في السلسلة الثانية. في السلسلة الثالثة كانت نسبة الأسمنت ثابتة (4%) بينما تتراوح نسبة السيراميك بين (4-12%) من وزن التربة. كذلك فحصت التربة بدون أي إضافات لإيجاد تأثير هذه الإضافات. بينت النتائج بأن أفضل تحسين في خصائص الرص ينجز عندما تعالج العينة بإضافة خليط الأسمنت والخزف, حيث وجد أن الكثافة الجافة العظمى تزداد بزيادة محتوى الخليط, بينما العكس صحيح لمحتوى الماء الأمثل. بينت النتائج أن الكثافة الجافة العظمى للتربة الجبسيه المعالجة بمادة الخزف تزداد بزيادة محتوى الخزف إلى حد 8% بعدها تتناقص الكثافة.

Keywords

Soil --- Gypsum --- Ceramic --- Cement --- Compaction


Article
Improvement of Physical and Mechanical Properties of Iraqi Gypsum Using Resole Resin

Author: Atheer Alaa Abdulhussein
Journal: journal of kerbala university مجلة جامعة كربلاء ISSN: 18130410 Year: 2012 Volume: 10 Issue: 2 Pages: 211-220
Publisher: Kerbala University جامعة كربلاء

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Abstract

The objective of the present work is to improve physical and mechanical properties of local gypsum reinforced with Resole resin. The water-gypsum ratio was kept at 45% throughout all these experiments. The prepared composites show a clear improvement in impact, compression strength and modulus of elasticity while, the bending strength is reduced when the Resole resin proportion in gypsum was increased from 2.5 to 10%. The other objective of this study was to evaluate the water absorption of Resole –gypsum composite. From the experimental results it may be concluded that swelling % was reduced when the Resole percentage in gypsum- Resole composite was increased.

الهدف من العمل هو بتحسين الخواص الميكانيكية والفيزيائية للجبس المحلي المعزز براتنج الريسول. نسبة الماء الى الجبس ثبتت على نسبة 45% خلال جميع التجارب. النماذج المتراكبة المحضرة من راتنجResole)) مع الجبس حصل فيها تحسين ملحوض في قوة التصادم والانضغاط ومعامل المرونة في حين لوحظ هناك انخفاض في قوة الانحناء عندما تغيرت نسبة الريسول في الجبس من 2.5% الى 10% الهدف الاخر من هذه الدراسة هو تقييم امتصاص الماء من قبل متراكبات الجبس والريسول. من النتائج العملية ظهر بشكل واضح, ان درجة الانتفاخ تقل كلما ازدادت نسبة راتنج الريسول في متراكبات جبس-ريسول.


Article
Evaluation of Some Physical Properties of Die Stone Made From Local Raw Gypsum Material

Authors: Lamia T Rejab --- Salwan F Al-Hamdani --- Mohammed Y
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2012 Volume: 12 Issue: 20 Pages: 309-315
Publisher: Mosul University جامعة الموصل

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Abstract

Aim: The aim of this study was to prepare die stone material by dehydration of the local natural raw gypsum in boiling with 30% calcium chloride solution , and then evaluated some physical properties of this prepared die stone. Materials and methods : The values of some physical properties of the pre-pared die stone in boiling with 30% calcium chloride solution which are water/powder ratio, setting time, and compressive strength were compared with that of three types of gypsum products commer-cial die stone, Elite type III dental stone and Iraqi plaster. The data were collected , mean and standard deviation were determined. Statistically, (ANOVA) and Dunnett Pairwise Multiple Comparison test were carried out to determine the significant differences at p≤ 0.05 Results: Results showed that there were no significant differences between the locally prepared die stone and the commercial one at p≤ 0.05 in water/powder ratio and setting time values, but it was significant difference in compressive strength. But there are a significant difference between the physical properties of the locally prepared die stone and Elite type III dental stone and Iraqi plaster. Conclusions: The results showed the physical properties of the locally prepared die stone approach the physical properties of the commercial product according to the recommendation of ADA for gypsum products.


Article
Evaluation of Some Physical Properties of Locally Prepared Alpha-calcium Sulfate Hemihydrate

Author: Lamia T Rejab
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2013 Volume: 13 Issue: 21 Pages: 14-20
Publisher: Mosul University جامعة الموصل

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Abstract

Aims: Aim of the study is to evaluate some physical properties of locally prepared dental stone form natural gypsum by two different calcination methods with autoclave with and without adding crystal habit modifier during calcination procedure for different periods of time. Materials and methods: The values of some physical properties that include specific gravity, water/ powder ratio and linear setting expansion of the prepared dental stone with autoclave with and without adding crystal habit modifier during calcination procedure for different periods of time and compared with that of commercial den-tal stone. ANOVA and Duncan's multiple range test were performed to determine the significant differ-ence among the tested groups at p ≤ 0.05%. Results: Results showed that there were significant differ-ences of the values of the physical properties between the locally prepared dental stone with autoclave and the commercial one at p≤ 0.05 in specific gravity, water/ powder ratio and linear setting expansion. Conclusions :The results appeared the alpha- calcium sulfate hemihydrates dental stone that prepared in autoclave with adding crystal habit modifier has superior properties than of that prepared without modifier, but still not reach the properties of the commercial product. All values of the tested proper-ties were in accordance with ADA Specification


Article
Properties of Keene's Cement-Quick Set Locally Product

Authors: Nadia S. Esmael --- Muhanned S. Gereed
Journal: Tikrit Journal of Engineering Sciences مجلة تكريت للعلوم الهندسية ISSN: 1813162X 23127589 Year: 2016 Volume: 23 Issue: 1 Pages: 53-60
Publisher: Tikrit University جامعة تكريت

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Abstract

Gypsum has been used as building material over a very long period of time. The production of gypsum plaster in Iraq confined on three types; plaster of Paris, ordinary gypsum and mechanical gypsum. The purpose of this study is to present a proposal to produce another type of gypsum plaster called Keene's cement, it has improvement characterizes than the other types of gypsum. In this study different percentage of alum solution has been used to soaked in gypsum lumps and different recalcinating temperatures also have been used. The results show that 12% of alum and 250 C° recalcinating temperature gave the highest result of compressive strength of Keene's cement product.

Keywords

Gypsum --- Keene's cement --- Alum


Article
Gypsum Mud Rheological Behavior

Author: Wissam.H.AL-Hashimi,
Journal: Journal of Petroleum Research & Studies مجلة البحوث والدراسات النفطية ISSN: 22205381 Year: 2017 Issue: 15 Pages: 28-50
Publisher: Ministry of Oil وزارة النفط

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Abstract

Gypsum muds are considered as the most important ones used in oil well drilling due to their thermal stability in addition to the durability of their ingredients. The main aim of this work is to study the effect of the gypsum mud compositions on their rheological behavior under the conditions of high-pressure and high temperature. Eleven samples of gypsum mud were tested using Fann viscometer model 50-C. All the tested samples had the same trend of reduction in both plastic viscosity and yield point with increasing temperature. The results showed that with 5 ppb of Q Broxine thermal degradation is obtained at approximately 150 0 F; this is due to the over treatment with thinner which result in more soluble solids and higher rheological properties while the decrement in NaOH concentration from 0.7 ppb to 0.35 ppb results in an increase in both yield point and plastic viscosity; this is due to the loss of OH-1 ions. Six rheological models were adopted: Bingham, power law, modified power law, Robertson stiff, modified Robertson stiff and Casson. Both Robertson stiff model and Casson model showed more acceptable values that fit the experimentaldata accurately.


Article
Mineralogy, Petrography and Chemistry of Two Local Plasters, Iraq
معدنية وبتروغرافية وكيميائية نوعين من البلاستر المحلي

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Abstract

The mineralogy, petrography and chemistry of two local plasters (Rasheed and Madae'n) and a dental stone were studied. Mineralogical studyby x-ray diffraction spectrometer proved that the three gypsum products consist mainly of bassanite or hemihydrate (CaSO4. 0.5 H2O) with minor amounts of gypsum and anhydrite. The petrography of the studied thin sections, reveals that the two local plasters consist of dispersed prismatic, monoclinic crystals withill-defined edges (bassanite of the β-hemihydrate). Dental stone consists of more packed, prismatic monoclinic crystals with well-defined and sharp edges(bassanite of the α–hemihydrate). Compressed powders of the two local plasters improved their crystal shapes and edges and made their outlines similar to dental stone or (α–hemihydrate).Chemical analyses of Rasheed and Madae'n plasters suggest that they consist of more than (96%) bassanite with small amounts of gypsum and anhydrite. Based on these compositions, the two local plasters are suitable for moulding, casting and constructional purposes. They are unsuitable for surgical plasters.

تم دراسة معدنية وبتروغرافية وكيميائية نوعين من البلاستر (الجبس) المحلي الرشيد والمدائن وحجر الاسنان. أوضحت الدراسة المعدنية بواسطة جهاز الأشعة السينية الحائدة (XRD) إن نواتج الجبسوم الثلاثة تتكون بصورة رئيسة من معدن باسنايت أو هيميهايدرايت مع كميات قليلة من الجبسوم والانهايرايت. وأوضحت الدراسة البتروغرافية لمساحيق هذه النواتج بأن نوعي البلاستر المحلي يتكونان من بلورات متباعدة موشورية احادية الميل وذات حافات غير منتظمة (باسنايت من نوع β-hemihydrate). ويتكون حجر الأسنان من بلورات موشورية احادية الميل اكثر تراصا وذات حافات منتظمة (باسنايت من نوع α–hemihydrate). وبعد تسليط ضغط معين على مسحوق النوعين من البلاستر المحلي، تبين ان الأشكال البلورية اصبحت اكثر انتظاما والحافات اكثر وضوحا مما قبل عملية الانضغاط وأن هذه البلورات تشبه بلورات حجر الأسنان وقريبة من (α–hemihydrate).وأوضحت التحاليل الكيميائية لبلاستر الرشيد والمدائن بأنهما يتكونان من معدن باسنايت بنسبة اكبر من (%96) مع كمية قليلة من الجبسوم والأنهايدرايت واعتمادا على التركيب الكيميائي فإن هذين النوعين من البلاستر يصلحان لأعمال القولبة والصب (moulding and casting) وأعمال البناء كذلك، ولا يصلحان لاستعمال البلاستر الجراحي (surgical plaster).


Article
The Application of Color Composite Image in Detecting and Delineation Difference Reflection of Gypsum in Surface Soil of Al-Jazeera Area in Nineveh Governorate Iraq
استخدام المرئيات المركبة لونيا في كشف وتحديد الاختلافات الانعكاسية للجبسوم في الترب السطحية لمنطقة الجزيرة في محافظة نينوىه العراق

Author: Namik A. Daood نامق عبد المنعم داود
Journal: Iraqi National Journal of Earth Science المجلة العراقية الوطنية لعلوم الارض ISSN: 16823222 Year: 2009 Volume: 9 Issue: 2 Pages: 17-26
Publisher: Mosul University جامعة الموصل

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Abstract

This work represents an attempt to recognize and delineate the area of different reflection of gypsum in the surface soil of Al- Jazeera region in the Ninevah Governorate, depending on the variations in the spectral reflectance of the gypsum and other landform features in the study area. This investigation utilized the three bands (TM1, TM4 and TM7) of the Landsat7 immerging together by using the ERDAS program to produce single color composite image, including the use of three primary colors (Red ,Green and Blue) respectively. Given these conditions, the basic principles of visual interpretation of images are all that is required of interpreter to implement them by using the color theory and the available field references about the area. The present study concluded the presence of three different levels of gypsum in the top soil surface of the Al- Jazeera North Western Iraq. which are recognized in the color composite image. These results are confirmed by both field visits and laboratory analysis of soil sample.

يهدف البحث الحالي إلى كشف وتحديد مناطق الاختلافات الانعكاسية للجبسوم في ترسبات الترب السطحية لمنطقة الجزيرة في محافظة نينوى اعتمادا على تباين الانعكاسية الطيفية للجبسوم وبقية المعالم الأرضية الموجودة في منطقة الدراسة. تم اختيار حزم المرئيات الثلاثة TM1,TM4,TM7, للمتحسس راسم الخرائط الموضوعي المحسن للقمر الاصطناعي الأمريكي ( لاندسات 7) والتي دمجت مع بعضها باستخدام برنامج ( ايرداس) لتكوين مرئية واحدة مركبة لونياً وذلك بإعطاء كل حزمة لون من الألوان الرئيسة ( الأحمر، الأخضر والأزرق ) على التوالي. تم إجراء التفسير البصري بالاعتماد على نظرية الألوان، مبادئ التفسير البصري وبعض المعلومات المرجعية الحقلية المتوفرة عن منطقة الدراسة. خلصت الدراسة إلى تحديد ثلاث مستويات متباينة في توزيع مناطق انعكاسية الجبسوم في ترسبات الترب السطحية لمنطقة الجزيرة شمال غرب العراق في المرئية المركبة و المميزة لونياً. هذه النتائج تم تدقيقها بالاعتماد على الزيارات الحقلية والتحليلات المختبرية للنماذج الترابية.

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