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%.
An experimental investigation of the variation of argon discharge current with a glow and afterglow time intervals of a square discharge voltage was carried out at low pressure (6-11 mbar). The discharge was created between two circular metal electrodes of diameter (7.5 cm), separated horizontally by a distance (10 cm) at the two ends of a Pyrex cylindrical tube. A composite of two Gaussian functions has been suggested to fit and explain the variation graphs clearly. It is shown that the necessary times of glow and afterglow needed to attain a maximum discharge current are (70 us) and (60 us), respectively. The discharge current is observed to drop to the lowest value when the two times are serially longer than (85 us) and (72 u
... Show Moreتستخدم تقنيات التصنيفِ ًبصورة واسعة جدا في كثير من المجالات التطبيقية. ولاسيما في المجالات الاقتصادية والتحليلات المالية كما في عِلْمِ تحليل الزبونِ التنبؤيِpredictive customer analytics ، الذي يتضمن ذلك الإمتلاكِ، المقايضة، إحتكار وإحراز الإئتمانِ والجباياتِ. إنّ هدفَ أيّ نموذج تصنيفِ هو أَنْ يُصنّفَ َ المشاهدات في مجموعتين أَو أكثرِ للوصول الى التنبؤ بنتيجةً ترتبط بكُلّ مشاهدة ومثا
... Show MoreFinancial institutions, including banks, remain a major target for money launderers in order to transfer illegal funds to legitimate funds through limited internal audit procedures and external auditing.
The study is a study of the operations of money laundering and what can be done by the verification efforts when integrated in the fight against them, by analyzing the level of cooperative relationship and communication between them. To achieve the objectives of the study, a questionnaire prepared for this purpose was distributed to an appropriate sample of (60) auditors of the internal audit staff of the Central Bank of Iraq and the external auditors working in the Federal control foundation Accordingly , appropriate methods wer
... Show MoreWives generally and working wives especially may encounter in some
families forms of physical or psychological violence through all the
levels or whether it was a psychological intimidation or cursing and
insolence and detracting her human . value and the husband marries
another woman or uses physical abuse against her and beating and
sexual abuse of the wife are also included in this from . it is noticed that
the violent attitude of the husband may take one from or it may change
and alter with time for it might lead to the increase of the possibility of
violence to occur in different ways
The importance of this study comes out from the step that on which in
folds the problem of the use of the husband of vio
الآخر في الشعر العربي الحديث (من نكسة حزيران إلى أخريات الألفية الثانية)
اهتمت المجتمعات العالمية في الآونة الأخير بفئة الأطفال ، ورعاية الطفولة وذلك لما لها من أهمية كبيرة في مستقبل المجتمع ، وتنميتة وتقدمه . لأنها يعتمد عليها في تقدم وتطور المجتمع فـي جميع المجالات الاقتصادية والاجتماعية والثقافية . ومن هنا ارتبطت الطفولة بالحياة برباط عضوي فالأطفال براعم الحياة ومع هذه البراعم تستمر الحياة لذلك اهتمت دول العالم بوضع البرامج وعقد المؤتمرات من اجل النهوض
... Show MoreIn this paper the use of a circular array antenna with adaptive system in conjunction with modified Linearly Constrained Minimum Variance Beam forming (LCMVB) algorithm is proposed to meet the requirement of Angle of Arrival (AOA) estimation in 2-D as well as the Signal to Noise Ratio (SNR) of estimated sources (Three Dimensional 3-D estimation), rather than interference cancelation as it is used for. The proposed system was simulated, tested and compared with the modified Multiple Signal Classification (MUSIC) technique for 2-D estimation. The results show the system has exhibited astonishing results for simultaneously estimating 3-D parameters with accuracy approximately equivalent to the MUSIC technique (for estimating elevation and a
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