Double-layer micro-perforated panels (MPPs) have been studied extensively as sound absorption systems to increase the absorption performance of single-layer MPPs. However, existing proposed models indicate that there is still room for improvement regarding the frequency bands of absorption for the double-layer MPP. This study presents a double-layer MPP formed with two single MPPs with inhomogeneous perforation backed by multiple cavities of varying depths. The theoretical formulation is developed using the electrical equivalent circuit method to calculate the absorption coefficient under a normal incident sound. The simulation results show that the proposed model can produce absorption coefficient with wider absorption bandwidth compared with the conventional double- and even triple-layer MPPs. The bandwidth can be increased to higher frequency by decreasing the cavity depth behind a sub-MPP with small hole diameter and a high perforation ratio, and to lower frequency by increasing the cavity depth behind a sub-MPP with large hole diameter and a small perforation ratio. The experimental data, measured by impedance tube, are in good agreement with the predicted results.
<span lang="EN-US">In the last years, the self-balancing platform has become one of the most common candidates to use in many applications such as flight, biomedical fields, and industry. In this paper, the physical prototype of a proposed self-balancing platform that described the self-balancing attitude in the (X-axis, Y-axis, or biaxial) under the influence of road disturbance has been introduced. In the physical prototype, the inertial measurement unit (IMU) sensor will sense the disturbance in (X-axis, Y-axis, and biaxial). With the determined error, the corresponding electronic circuit, DC servo motors, and the Arduino software, the platform overcame the tilt angle(disturbance). Optimization of the proportional-integral-
... Show MoreWe consider the outflow of water from the peak of a triangular ridge into a channel of finite depth. Solutions are computed for different flow rates and bottom angles. A numerical method is used to compute the flow from the source for small values of flow rate and it is found that there is a maximum flow rate beyond which steady solutions do not seem to exist. Limiting flows are computed for each geometrical configuration. One application of this work is as a model of saline water being returned to the ocean after desalination. References Craya, A. ''Theoretical research on the flow of nonhomogeneous fluids''. La Houille Blanche, (1):22–55, 1949. doi:10.1051/lhb/1949017 Dun, C. R. and Hocking, G. C. ''Withdrawal of fluid through
... Show MoreAbstract
Objective(s): to Evaluation of Parents’ Knowledge about Nutritional Management of kids with Phenylketonuria; to Identify the association between parents’ Knowledge about nutritional management then their demographic variables of fathers, mothers (parents age, residence then socioeconomic position).
Methodology: A non-experimental project; was accompanied on parents of phenylketonuria kid in Baghdad town since the period 3 June to 5 October 2022. A Non-probability sample (convenience) of 35 PKU children and their parents (father and mother) was selected Purposively from the hospitals that are select for the study. A survey is built for the purpose of the educa
... Show MoreDue to the spread of insect pests that destroys the crops belonging to the Cucurbitaceae family and led to deterioration in crop productivity in Iraq due to various reasons, the most important of which is Climate fluctuation and extreme weather events have a major impact on this problem. So, this paper was proposed to identify those species pests and prevalence. Insects were collected during the period from March 1. 2022 to October 30, 2022 from the several regions of Iraq, including: Baghdad, Babylon, Basra, Karbala, Wasit, Diyala, Saladin, and Duhok Provinces. The results showed 19 important species under 17 genera with 13 families, and five orders. The most common synonyms and dist
One of the important objectives of the varistor is for a sustainable environment and reduce the pollution resulting from the frequent damage of the electrical devices and power station waste. In present work, the influence of Al2O3 additives on the non –linear electrical features of SnO2 varistors, has been investigated, where SnO2 ceramic powder doped with Al2O3 in three rates (0.005, 0.01, and 0.05), the XRD test improved that SnO2 is the primary phase, while CoCr2O4, and Al2O3 represent the secondary phases. The electrical tests of all prepared samples confirmed that the increasing of Al2O3 rates and sintering temperature improves and increase the electrical features, where the best results obtained at Al2O3 (0.05) and 1000℃, the non
... Show MoreBackground: Knee osteoarthritis (KOA) is a common joint disorder leading to considerable pain and locomotor disability in lower limb function. Locomotor disability, which is difficulty in activities of daily living related to lower limb function, can be the consequence of KOA, so early diagnosis and management may improve quality of life.
Objective: To assess the contribution of radiological osteoarthritis of the knees to disability in the activities of daily living related to lower limb function.
Methods: One hundred twenty Iraqi KOA patients (104 females and 16 males) who were attending to Rheumatology Unit, Full history was taken and complete clinical exami
... Show MoreABSTRACTBackground: dyslipidemia plays a crucial rule in the development of cardiovascular disease, which has become the leading cause of death in most developed countries as well as in developing countries (1). The effects of reducing low density lipoprotein – C (LDL-C) concentrations on the prevention of cardiovascular events and stroke have been well reported in many clinical trials.Objectives: Evidence supports the use of statins for lipid modifications in the primary prevention of coronary artery disease, morbidity and mortality. This study aims to determine the effectiveness of atorvastatin in treating dyslipidemia in Iraqi obese patients.Methods: 200 overweight and obese patients with hypercholesterolemia, according to NCEP ATP
... Show MoreAn attempt was made to determine the insect parasites of cockroaches in Iraq. As a result of this survey three species of Hymenoptera representing two separate families, which have been reared from ootheca of cockroaches were recovered. These were: Evania dimidiata Fabricius, Evania appendigaster (Linnaeus) (Evaniidae) and Anastatus longicornis sp. n. (Eupelmidae) which described here as a new species from Iraq.
Background: the activity of acute lymphoblastic leukemia had been observed to correlate with levels of serum lipoproteins
Objective: to evaluate the correlation of serum levels of different types of lipoproteins with activity of the disease in patients with acute lymphoblastic leukemia.
Type of the study: A prospective study.
Methods: A study included patients diagnosed as acute lymphoblastic leukemia, their serum levels of lipoproteins at time of diagnosis, and on relapse were obtained for comparison.
Results: there is significant inverse correlation of activity of acute lymphoblastic leukemia with serum total cholesterol
... Show More