Due to the potential cost saving and minimal temperature stratification, the energy storage based on phase-change materials (PCMs) can be a reliable approach for decoupling energy demand from immediate supply availability. However, due to their high heat resistance, these materials necessitate the introduction of enhancing additives, such as expanded surfaces and fins, to enable their deployment in more widespread thermal and energy storage applications. This study reports on how circular fins with staggered distribution and variable orientations can be employed for addressing the low thermal response rates in a PCM (Paraffin RT-35) triple-tube heat exchanger consisting of two heat-transfer fluids flow in opposites directions through the inner and the outer tubes. Various configurations, dimensions, and orientations of the circular fins at different flow conditions of the heat-transfer fluid were numerically examined and optimized using an experimentally validated computational fluid-dynamic model. The results show that the melting rate, compared with the base case of finless, can be improved by 88% and the heat charging rate by 34%, when the fin orientation is downward–upward along the left side and the right side of the PCM shell. The results also show that there is a benefit if longer fins with smaller thicknesses are adopted in the vertical direction of the storage unit. This benefit helps natural convection to play a greater role, resulting in higher melting rates. Changing the fins’ dimensions from (thickness × length) 2 × 7.071 mm2 to 0.55 × 25.76 mm2 decreases the melting time by 22% and increases the heat charging rate by 9.6%. This study has also confirmed the importance of selecting the suitable values of Reynolds numbers and the inlet temperatures of the heat-transfer fluid for optimizing the melting enhancement potential of circular fins with downward–upward fin orientations.
Electrical distribution system loads are permanently not fixed and alter in value and nature with time. Therefore, accurate consumer load data and models are required for performing system planning, system operation, and analysis studies. Moreover, realistic consumer load data are vital for load management, services, and billing purposes. In this work, a realistic aggregate electric load model is developed and proposed for a sample operative substation in Baghdad distribution network. The model involves aggregation of hundreds of thousands of individual components devices such as motors, appliances, and lighting fixtures. Sana’a substation in Al-kadhimiya area supplies mainly residential grade loads. Measurement-based
... Show MoreIt is becoming a public health issue to predict which expectant women will develop gestational diabetes mellitus (GDM). The goal of this case control research is to investigate the role of maternal oxidative stress levels in the first, second, and third trimesters, as well as other factors, in the development of gestational diabetes mellitus (GDM). Methods Between October and December 2021, 142 women participated in this research. The 101 GDM patients were split into three groups based on their gestation (T1, T2, and T3), and 41 healthy pregnant women were chosen as the comparison group. TAS and TOS levels of oxidative stress and XO were calculated using a Spectrophotometer for colorimetric techniques; fasting and random sugar levels, as
... Show MoreIn this paper we generalize some of the results due to Bell and Mason on a near-ring N admitting a derivation D , and we will show that the body of evidence on prime near-rings with derivations have the behavior of the ring. Our purpose in this work is to explore further this ring like behavior. Also, we show that under appropriate additional hypothesis a near-ring must be a commutative ring.
Background: Polycystic ovary syndrome (PCOS) is
the most common form of chronic anovulation
associated with androgen excess; it occurs in about 5
– 10% 0f reproductive age women. Metabolic
syndrome is characterized by insulin resistance,
hypertension, obesity, abnormalities of blood clotting
and dyslipidemia.
Adult women with PCOS have an increased
prevalence of the metabolic syndrome(MBS).
Objectives: To detect the prevalence of metabolic
syndrome in women with proved PCOS, attending the
Specialized Center for Endocrinology and Diabetes, in
Baghdad.
Materials and methods : A total number of 40
women with proved PCOS were included in this study
which was conducted in the Specialized Center f
The non static chain is always the problem of static analysis so that explained some of theoretical work, the properties of statistical regression analysis to lose when using strings in statistic and gives the slope of an imaginary relation under consideration. chain is not static can become static by adding variable time to the multivariate analysis the factors to remove the general trend as well as variable placebo seasons to remove the effect of seasonal .convert the data to form exponential or logarithmic , in addition to using the difference repeated d is said in this case it integrated class d. Where the research contained in the theoretical side in parts in the first part the research methodology ha
... Show MoreBackground: Zinc is involved in a variety of
metabolic processes and it has a well known
antioxidant activity, so the measurement of its serum
level can have a special value in several diseases.
Objectives: The study is designed to determine the
serum zinc level in heart failure patients and to
compare it with that of healthy individuals and to
study the significance of the results obtained.
Methods: Atomic absorption spectrometer
technique was used to determine serum zinc level in
fifty heart failure patients and fifty healthy individuals
who were age and sex matched.
Results: The mean serum zinc level in healthy
individuals was about 45.5% greater than that of heart
failure patients. This diffe
Document clustering is the process of organizing a particular electronic corpus of documents into subgroups of similar text features. Formerly, a number of conventional algorithms had been applied to perform document clustering. There are current endeavors to enhance clustering performance by employing evolutionary algorithms. Thus, such endeavors became an emerging topic gaining more attention in recent years. The aim of this paper is to present an up-to-date and self-contained review fully devoted to document clustering via evolutionary algorithms. It firstly provides a comprehensive inspection to the document clustering model revealing its various components with its related concepts. Then it shows and analyzes the principle research wor
... Show MoreBackground: Dialysis is in common use to treat patients
with end stage renal failure .However longstanding dialysis
harboring some cellular changes in various body fluids.
This study was conducted in order to detect these changes
in urine.
Objective: The study was conducted to detect cellular
changes in urine of patients with longstanding dialysis.
Method: Fifty-three urine samples were examined
cytologically obtained from patients with longstanding
dialysis during 6 months period. Freshly voided midstream
urine samples were taken . Samples were centrifuged and 2
to 3 drops of sediments were smeared on 2 glass slides and
fixed in 95% ethyl alcohol then stained with Hand E stain
to be evaluated.
R
Praise be to God, who is satisfied with Islam as our religion, “He opened a clear conquest for us,” and whoever works with us through the Shari’ah works and protects us. And that our master and Mawlana Muhammad His servant and Messenger is a prophet who has been merciful and compassionate. "
And after:
The occupation of Iraq and the accompanying bone events, and the following severe obstacles, resulted in a set of problems that require legitimate stances, and satisfactory answers, remove confusion and delusion, amid the clash of opinions and contradictions of jurisprudence. Work and application.
Among the difficult problems that surfaced in light of the new political developments on the land of Iraq: (the ruling on dealing