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.
Diabetes mellitus, or simply diabetes, is a group of metabolic diseases in which a person has high blood sugar, either because the pancreas does not produce enough insulin, or because cells do not respond to the insulin that is produced. This high blood sugar produces the classical symptoms of polyuria (frequent urination), polydipsia (increased thirst), and polyphagia (increased hunger). The aim of the study is to measure several biochemical parameters in T2DM patients and the effect of these parameters in development the disease. Laboratory investigations including Ceruloplasmin , fasting blood glucose (FBG) , malondialdehyde (MDA), serum protein, uric acid, and protein electrophoresis have been measured in patients with type
... Show MoreThe inelastic longitudinal electron scattering form factors are calculated for the low-lying excited states of 7Li {the first excited state 2121TJ (0.478 MeV) and the second excited state 2127TJ (4.63 MeV)}. The exact value of the center of mass correction in the translation invariant shell model (TISM) has been included and gives good results. A higher 2p-shell configuration enhances the form factors for high q-values and resolves many discrepancies with the experiments. The data are well described when the core polarization (CP) effects are included through effective nucleon charge. The results are compared with other theoretical models.
Keyword: 7Li inelastic electron scattering form factors calculated with exact
With the increasing intensity of the ecological and environmental problems and the scarcity of fresh water, this paper was introduced to investigate the ability to use treated wastewater as a cooling media via studying its behavior throughout a cooling tower. The simultaneous transfer of heat and mass from the treated wastewater to air over splash-fill packing arranged in a zigzag manner was studied. The characteristic of the cooling tower, the outlet water temperature, and the rejected heat were investigated as the water-to-air ratio and inlet water temperature were varied. The core results show that the cooling tower of the tower decreases with increasing water-to-air ratio, and increases with the raise of inlet water temperature.
... Show MoreThis study aims to focus on the Motives behind volunteer work among a sample of volunteers working in civil society organizations and check if there are statistical differences with those variables according to (gender, age, job, period of volunteer work, and residence. The sample consists of (220 )volunteers,(189) male and(31) female from southern, northern and central governorate .The Volunteer Functions Inventory(VFI)(Clary & et al,1989)was applied, It consisting of(30) items with six fields( Values, Understanding, Social motives, Career, Protective, Enhancement).
The results show that the most common and important motivations are (Values, Understanding, and social motivations), there are differenc
... Show MoreIn this research, we introduce and study the concept of fibrewise bitopological spaces. We generalize some fundamental results from fibrewise topology into fibrewise bitopological space. We also introduce the concepts of fibrewise closed bitopological spaces,(resp., open, locally sliceable and locally sectionable). We state and prove several propositions concerning with these concepts. On the other hand, we extend separation axioms of ordinary bitopology into fibrewise setting. The separation axioms we extend are called fibrewise pairwise T_0 spaces, fibrewise pairwise T_1 spaces, fibrewise pairwise R_0 spaces, fibrewise pairwise Hausdorff spaces, fibrewise pairwise functionally Hausdorff spaces, fibrewise pairwise regular spaces, fibrewise
... Show Morewhich is much useful in the Arabic Language generally in the Holly Quran especially. It is the pronoun I have taken in the semantic aspect from it and I have done on the surra sabba which varities the semantical pronoun in it among the pronoun of the speaker the conscience of the addressee the absent such the the siprat pronoun that comes in it with the explanation for its importance and its work and this is the subject of the first unit which I advanced it from the concept of the pronoun Linguistically and convention. After that I have lighten in some meanings which I have done in the surrat as a semantic , magnification , proud, reprimand and others which I ended my research I have reached the results from it
... Show MoreThe humid and warm conditions in greenhouses provide an excellent environment for pests’ living conditions, and therefore, they provide ideal medium for alien introductions. Molluscs are among the most significant pests that infest plastic covered greenhouses. To identify and report their mollusc species, 23 greenhouses in Iraq were surveyed between March 2023 and April 2024. Of these, 11 were found to be infested with snails. A total of 158 specimens were collected and morphologically identified to seven species: Monacha obstructa (L. Pfeiffer, 1842), Eobania vermiculata (O.F. Müller, 1774), Xeropicta krynickii (Krynicki, 1833), Rumina decollata (Linnaeus, 1758), Polygyra cereolus (Megerle Von Mühlfeld, 1818), Cochlicella barba
... Show MoreTrimethoprim derivative Schiff bases are versatile ligands synthesized with carbonyl groups from the condensation of primary amines (amino acids). Because of their broad range of biological activity, these compounds are very important in the medical and pharmaceutical fields. Biological activities such as antibacterial, antifungal and antitumor activity are often seen. Transition metal complexes derived from biological activity Schiff base ligands have been commonly used
Trimethoprim derivative Schiff bases are versatile ligands synthesized with carbonyl groups from the condensation of primary amines (amino acids). Because of their broad range of biological activity, these compounds are very important in the medical and pharmaceutical fields. Biological activities such as antibacterial, antifungal and antitumor activity are often seen. Transition metal complexes derived from biological activity Schiff base ligands have been commonly used.