This paper aims to study the effect of circular Y-shaped fin arrangement to improve the low thermal response rates of a double-tube heat exchanger containing Paraffin phase change material (PCM). ANSYS software is employed to perform the computational fluid dynamic (CFD) simulations of the heat exchanger, including fluid flow, heat transfer, and the phase change process. The optimum state of the fin configuration is derived through sensitivity analysis by evaluating the geometrical parameters of the Y-shaped fin. For the same height of the fins (10 mm), the solidification time is reduced by almost 22%, and the discharging rate is enhanced by almost 26% using Y-shaped fins compared with the straight fins. The results demonstrate that the solidification time is inversely proportional to the fin's length. The heat release rate for the case with the longest fins (stem length of 10 mm) is 39 W, almost 2.8 times higher than that with the fins' stem length of 5 mm. The case with the tributary's angle of 22.5o solidified in 55 min, faster than the other studied angles. Increasing the number of fins significantly affects the solidification time and discharging rate. By increasing the number of fins from 3 to 9, the heat transfer rate improves by 194%. The advantages of circular Y-shaped fins are well known in heat transfer applications and therefore are characterized toward higher performance in this study for the first time during the solidification process.
The present paper addresses cultivation of Chlorella vulgaris microalgae using airlift photobioreactor that sparged with 5% CO2/air. The experimental data were compared with that obtained from bioreactor aerated with air and unsparged bioreactor. The results showed that the concentration of biomass is 0.36 g l-1 in sparged bioreactor with CO2/air, while, the concentration of biomass reached to 0.069 g l-1 in the unsparged bioreactor. They showed also that aerated bioreactor with CO2/air gives more biomass production even the bioreactor was aerated with air. This study proved that application of sparging system for cultivation of Chlorella vulgaris microalgae using either CO2/air mixture or air has a significant growth rate, since the biorea
... Show MoreIn this paper, we introduce the concept of cubic bipolar-fuzzy ideals with thresholds (α,β),(ω,ϑ) of a semigroup in KU-algebra as a generalization of sets and in short (CBF). Firstly, a (CBF) sub-KU-semigroup with a threshold (α,β),(ω,ϑ) and some results in this notion are achieved. Also, (cubic bipolar fuzzy ideals and cubic bipolar fuzzy k-ideals) with thresholds (α,β),(ω ,ϑ) are defined and some properties of these ideals are given. Relations between a (CBF).sub algebra and-a (CBF) ideal are proved. A few characterizations of a (CBF) k-ideal with thresholds (α, β), (ω,ϑ) are discussed. Finally, we proved that a (CBF) k-ideal and a (CBF) ideal with thresholds (α, β), (ω,ϑ) of a KU-semi group are equivalent relations.
Quantum channels enable the achievement of communication tasks inaccessible to their
classical counterparts. The most famous example is the distribution of secret keys. Unfortunately, the rate
of generation of the secret key by direct transmission is fundamentally limited by the distance. This limit
can be overcome by the implementation of a quantum repeater. In order to boost the performance of the
repeater, a quantum repeater based on cut-off with two different types of quantum memories is suggestd,
which reduces the effect of decoherence during the storage of a quantum state.
In this paper, the species of the genus of Chlaenius Bonelli, 1810 (Coleoptera, Carabidae) were reviewed, and it was revealed that there are 21 confirmed species in Iraq; among them, the species of Chlaenius hamifer Chaudoir, 1856 was recorded for the first time in Iraq.
Diagnostic characters, a redescription of some of the morphological features, photographs and illustrations are provided for the new record species in this investigation.
Thyroid hormones (TH) regulate the metabolic processes required for normal development and growth; also, to organizemetabolism in adults, any defect in thyroid function leads to abnormality in thyroid hormones level. The current study hasbeen designed to find the relationship between retinol-binding protein-4 and progranulin in the serum of Iraqi women withhypothyroidism and hyperthyroidism, also, to study whether these patients are exposed to a risk of developing diabetes mellitus,and PGRN may be a biomarker in detection early stage of diabetes mellitus.Materials and Methods: in this study, serum samples were obtained from 50 Iraqis women patients, [25 patients withhypothyroidism (G2) and 25 patients with hyperthyroidism (G3)] in addition
... Show MoreThe mathematical construction of an ecological model with a prey-predator relationship was done. It presumed that the prey consisted of a stage structure of juveniles and adults. While the adult prey species had the power to fight off the predator, the predator, and juvenile prey worked together to hunt them. Additionally, the effect of the harvest was considered on the prey. All the solution’s properties were discussed. All potential equilibrium points' local stability was tested. The prerequisites for persistence were established. Global stability was investigated using Lyapunov methods. It was found that the system underwent a saddle-node bifurcation near the coexistence equilibrium point while exhibiting a transcritical bifurcation
... Show MoreThe effect of ozone gas with temperatures 35. 40 and 45 Celsius to control on larval and adult stages of Tribolium castaneum was tested and at time of exposure 1.0, 3.0, 7.0, 9.0, 11.0, 13.0 hours and the level of relative humidity prevailing during the test 45 ± 1%. Results showed significant differences between the exposure times, when the percentage of mortality 100% between larvae (primary, intermediate and advanced) in the treatment effect at a temperature of 35 Celsius with ozone gas at exposure time to 9.0, 11.0, 11.0 hours for the three ages respectively, and adult (male and female) in the same treatment when the three heat degrees had given ratios the total mortality reached 100% of both males at exposure time to 7.0 ,3
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