A 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 method was employed to describe the heat storage and release in the mushy zone. Experimental results referred to an increase in thermal conductivity of paraffin wax that supported by copper foam matrix more than ten times. While the ventilation effect was still active for hours after the sun set, depending on the heat storage amount. Maximum ventilation mass flow rate with TESB collector was recorded with value equals to 36.651 kg/hr., when the overall discharge coefficient that was calculated for the system equals to 0.371. Experimental results showed that the best working angle range was 45~60o, and the highest air to the collector approaching temperature appeared to the double passes flat plate collector. Results gave greater heat storage efficiency of (47)% when the maximum solar radiation was 780 W/m2 at 12.00pm, while the energy summation through duration charge time was 18460 kJ. Computational results, depending on the equivalent heat capacity method for heat storage or release from phase change material that supported by copper foam matrix, showed the behavior of paraffin wax melting and solidification situation through periodic for charge and released heat from the solar collector. Also, these results gave agreement approaching the experimental results for the heat storage in the combined heat storage material, with standard error of 16.8%.
The study tackles the market orientation and the organizational learning as independent variables each included three sub-dimensions, and the variable of business performance as affiliated variable. These three variables have interacted to form the framework around which the study revolves. Since the banking sector has become an important part of which service sector is made, as well as it represents the basic pivot for the process of building and the development of the economies of countries, the Iraqi banking sector have been taken to be the sample of this study. A nonrandom sample of nine Iraqi banks was chosen, including four state banks (Al-Rafdain, Al-RaSheed, Industrial Bank, and Agricultural), and five private banks (Bagh
... Show MoreThe dispersion of supported Pt and Pt–Ir reforming catalysts have been studied, after treatment with oxidative and reducing atmosphere. Methylcyclohexane dehydrogenation reaction in the absence of hydrogen was used as a test reaction. An attempt was made to relate the behavior of the catalysts upon subject to reaction, to the dispersion of the same type of catalysts upon treatment with similar atmosphere and temperatures which appeared in literature. The total conversion of reaction can be explained by a change in metal dispersion. Thus, methylcyclohexane dehydrogenation reaction appears to be a really “structure sensitive” reaction.
The toluene yield increases as the oxidation temperature i
... Show MoreThe Strategy of employees' empowerment, organizational performance and total quality management represent three informative which were and still the hub of many studies and researches including the current study. The higher education is considered one of the most important services sectors and the main development as well as the civil progress in the society. It is the main source that provides the organizations with the human resources having scientific or practical professions. So Higher Education has been chosen especially Baghdad University as a sample of the study. The study problem is concentrated to find answers of the following questions: What the level of the powers mandate in the organization concerning the
... Show MoreAn experiment in the semester, the second semester of the academic year (2022-2023), and the data used was not processed (the second test for two independent, inaccurate samples, the Bermon correlation coefficient, and the Spearman correlation coefficient), and the following results were reached: There is a statistically significant difference at the level of ( 0) average, 05) between the third grade who studied the plan for asking cluster questions, and between the average of those who studied the special feature according to the traditional method of selecting achievement, and enjoyed completing the specialization, choosing the experimental group, because the strategy of asking cluster questions is one of the externalities that... Lear
... Show MoreThe researcher tried to show the importance of using environmental taxes as an effective economic factor for reducing contaminators resulting from cars exhausts, and presenting a suggested pattern for environmental taxes as a nucleus and a starting point for a wider implementing of environmental taxes in Iraq. &nbs
... Show Moreتضمن البحث التعريف بالإمام البزازي، وحياته العلمية، ومشايخه، وتلامذته، ومؤلفاته، ووفاته، وأربعة مسائل مختارة من ترجيحاته في الحدود والجنايات، والإمام محمد بن محمد بن شهاب بن يوسف (ت827هـ)، يُكنَّى بالكَردَرِيِّ الحنفي الخوارزمي الشهير بالبزَّازي، ويُنسب إلى كَرْدَر، وقد عرض في كتابه كثيرًا من كتب الحنفية، وذكر الكثير من آراء علمائهم مع تعرضه لبعض آراء المذاهب الأخرى. ولم يعتمد على التعريفات اللغوية والاصط
... Show Moreدراسة في رواية سعودية
The management of the overall quality (TQM)) of the philosophies that gained the attention of a large number of leaders and managers, practitioners and academics, as one of the prevailing management philosophies and desirable in the current period, is associated with the concept of quality itself, which shows the overall features and characteristics and attributes that related to the service and meet the needs of beneficiaries phenomenon and full, as was the concept of strategic performance with a significant level of interest from organizations because it is closely linked to the success of the organization in light of the changing competitive environment. These were the study in an attempt to see how a clear vision of the unive
... Show Moreيتناول البحث جزاء الاخلال بالوعد بالتعاقد في ضوء تعديل القانون المدني الفرنسي بموجب المرسوم رقم 131 لسنة 2016