تعد التجارب المختبرية من أهم الوسائل التي تمكن من فهم خصائص المواد الكيميائية وسلوكها، كما إنها الوسيلة الوحيدة لتحضير المركبات الكيميائية المختلفة. وقد أدى تطور التكنولوجيا في الوقت الحاضر إلى إستخدام أدوات وأجهزة قياس في المختبر مكنت من زيادة دقة نتائج التجارب وسرعة الحصول عليها. أن تفعيل المختبر وإجراء الأنشطة العملية يمكن أن تحقق عدة أمور منها : 1- تُنمي في الطالب مهارات التفكير العلمي ( الملاحظة ، وتحديد المشكلة، وفرض الفروض، وإختبار الفروض، وإختيار الفرض الصحيح ، الإستنتاج والتعميم ) 2- تنمية القدرة على حل المشكلات والتفكير الإبداعي . 3- تمكن الطالب من تكوين المفاهيم بدلاً من المعرفة المجردة . 4- تساعد الطالب على تكوين الميول والإتجاهات العلمية ونوع الإختصاص في المستقبل . 5- تساعد على ترسيخ المعلومة وبقاء أثر التعلم فترة أطول . 6- تكسب الطالب طرق التعامل مع الأدوات المختبرية والمواد الكيميائية والتعرف على مخاطرها عن قرب وفهم قوانين وقواعد السلامة في المختبر وتطبيقها والمحافظة على سيرالعمل والآلات والأجهزة الموجودة في المختبر. 7- بث روح التعاون بين الطلاب بين المجاميع المختبرية . ويغطي هذا الكتاب مما يحويه من المعلومات الضرورية الوافية لمساقين في الكيمياء اللاعضوية وخاصة في التعرف على الجدول الدوري للعناصر وكل مايحتاجه الطالب في الالمام بالمعلومات التي تفيده من خلال التعرف على المختبرات العملية والتي تخص المرحلة الثانية . ويتميز هذا الكتاب بشموله بالتجارب العملية لثلاثين تجربة والتي تخص حول مركبات عناصر في الجدول الدوري. ويعتبر هذا الكتاب كمدخل في توضيح العلاقة بين المنهج النظري والمنهج العملي بشكل مترابط المفاهيم من خلال تعرف الطالب على التجارب العملية لما لها من مجالات تطبيقية في بيئته. وإشتمل الكتاب على عشرة فصول : الفصل الأول: توجيهات مختبرية وتعليمات عامة - نموذج كتابة التقريرعن التجربة - التعرف على الأدوات والأجهزة المستخدمة في مختبر الكيمياء ، توضيح الطريقة الصحيحة للتعامل مع الأجهزة ، مبادئ السلامة الأمنية ، مخاطر المواد الكيميائية ، بطاقات التعريف ، قواعد السلامة في تخزين وتداول المواد الكيميائية ،الاشارة الى الإسستعمالات الخاطئة والصحيحة بشكل مخططات او صور او رسوم توضيحية وبعض الإسعافات الأولية . الفصل الثاني: معلومات حول الجدول الدوري للعناصر . الفصل الثالث :الهيدروجين وتجربة (1) وتخص الحوامض والقواعد والأملاح . الفصل الرابع- الفصل العاشر : التجارب من (2-30 ) تخص معلومات عن العناصر بزمر مختلفة مع ذكر المخاطر الكيميائية للمواد الكيميائية التي يتم التعامل معها في المختبر. الملاحق (Appendix ) : وتتضمن بعض الأجوبة النموذجية لبعض تجارب الكيمياء اللأعضوية الواردة في الكتاب مع أسماء جميع عناصرالجدول الدوري وبعض خواصها . الإشارات التحذيرية– إشارات المنع - الإشارات الإجبارية --الإشارات الإستدلالية .
The purpose of this study is to investigate the histopathological response of dentinopulpal
response of human teeth to the Er: YAG laser cavity preparation in comparison with the conventional
class I cavity preparation. Thirty five sound human upper and lower first premolar teeth which were
needed to be extracted for orthodontic purposes were used in the study. Regarding to the method of
cavity preparation, the teeth were grouped into three groups; Group1; Control group which consists of
seven sound teeth without cavity preparation, Group2; Conventional cavity preparation group and group
3; Er: YAG laser cavity preparation group. Each of Group2 and3 consists of fourteen teeth that is
subdivided into: A. 7teeth that e
his project try to explain the using ability of spatial techniques for land cover change detection on regional level with the time parameter and did select for explain these abilities study case (Hewaizah marsh ) . this area apply to many big changes with the time. These changes made action on characters and behaviors of this area as well as all activities in it . This Project concerting to recognize the Using importance of remote sensing and GIS Methodology in data collecting for the changes of land use and the methodology for the analyses and getting the results for the next using as a base data for development and drawing the plans as well as in regional planning .This project focus on practical
... Show MoreThe research aims to demonstrate the dual use of analysis to predict financial failure according to the Altman model and stress tests to achieve integration in banking risk management. On the bank’s ability to withstand crises, especially in light of its low rating according to the Altman model, and the possibility of its failure in the future, thus proving or denying the research hypothesis, the research reached a set of conclusions, the most important of which (the bank, according to the Altman model, is threatened with failure in the near future, as it is located within the red zone according to the model’s description, and will incur losses if it is exposed to crises in the future according to the analysis of stress tests
... Show MoreThis study focuses on the biodegradation of oxymatrine insecticide by some soil fungi isolated from four agriculture stations. The results showed that the highest degradation rate 94.66% was recorded by Ulocladium sp. at 10 days and A. niger recorded the lowest degradation rate 45.86%, while at 20 days Ulocladium sp. also showed the highest degradation rate 94.98% and the lowest degradation rate reached to 82.49% with A.niger. The mix (Exerohilum sp.+Ulocladium sp.) recorded the highest degradation rate of oxymatrine insecticide 90.22%, 88.51%, 85.34% at 4, 8 and 12 ppm.The use of mixed isolates enhanced the biodegradation process. There is no study of oxymatrine biodegradation
... Show Moreتم في هذه الدراسة أعادة التخطيط لتوزيع الهيئات الرقابية على االدارات الخاضعة لتدقيقها لدائرة تدقيق نشاط التمويل والتوزيع في ديوان الرقـابة المالية االتحادي ، وتم بناء أنموذج التخصيص العـام اعتمادا"على لسنة أنجاز أعمال الهيئات الرقابية لالدارات الخاضعة (2016 (أوقـات,حيث أنـه تـم بنـاء أنموذج ريـاضي لتدقيقهاللمجموعة االولى لهيئات هـذه الدائرة وذلك للحصول علىالتخصيص األمثل للهيئات الـرقـابية على االدارات وي
... Show More A prominent figure such as Yahya bin Khaldoun and a scholar of the moroccan countries in the medieval era, and had a special place in the history of the country and the state of Bani Zayan, and the positions he occupied in it and left his scientific, literary and historical traces, leaving him an imprint in the course of history and its events, and in this study
I dealt with the research: his personal life : his name and lineage, then his upbringing and his family.
The aim of the study is to know this character in the details of his personal and scientific life, according to the historical descriptive research method, including description and presentation of events, and linking them in a
... Show MoreThe self-evident truth existing in today's business environment is the continuity of change and its continuity and turmoil, also its increase over time as it is more abundant, abundant, wide and complex than ever before, and it is the dominant feature in the business environment, as different organizations and operating units can find themselves shifting from the top to the bottom. And then it requires its departments to strive to adapt to these rapid and turbulent shifts and changes by bringing about a series of organizational and adaptive changes that are not limited to one organizational aspect only but rather include all organizational components. Accordingly, this research came to determine the readiness of public organizations to chan
... Show MoreA paraffin wax and copper foam matrix were used as a thermal energy storage material in the double passes air solar chimney (SC) collector to get ventilation effect through daytime and after sunset. Air SC collector was installed in the south wall of an insulated test room and tested with different working angles (30o, 45o and 60o). Different SC types were used; single pass, double passes flat plate collector and double pass thermal energy storage box collector (TESB). A computational model based on the finite volume method for transient tw dimensional domains was carried out to describe the heat transfer and storage in the thermal energy storage material of collector. Also, equivalent specific heat metho
... Show MoreAssessing performance efficiency is critical to the management need for oversight, planning, and continuous periodic evaluation of the multiple activities of Northern Cement State Company in order to determine the level of achievement of the objectives set, and to correct the deviations and delays that the evaluation shows and limitation of liability. What cannot be measured cannot be managed. The aim of this research is to highlight the impact of using BSC, financial and non-financial, to give comprehensive and clear picture of the company's performance and to measure the quality of its performance by using six-sigma and the level of deviations in achieving the planned goals. Therefore, four-key hypotheses were formulated for th
... Show MoreIn latest decades, genetic methods have developed into a potent tool in a number of life-attaching applications. In research looking at demographic genetic diversity, QTL detection, marker-assisted selection, and food traceability, DNA-based technologies like PCR are being employed more and more. These approaches call for extraction procedures that provide efficient nucleic acid extraction and the elimination of PCR inhibitors. The first and most important stage in molecular biology is the extraction of DNA from cells. For a molecular scientist, the high quality and integrity of the isolated DNA as well as the extraction method's ease of use and affordability are crucial factors. The present study was designed to establish a simple, fast
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