Modelling The Acoustic Performance Of Inhomogeneous Micro-Perforated Panel Absorber

Micro-perforated panel (MPP) absorber is increasingly gaining more popularity in noise control as a sound absorber given its facile installation, long durability, environmental friendliness and attractive appearance and as an alternative to the classical porous acoustics materials. A single MPP absorber typically features a Helmholtz resonator with a high absorption amplitude, but narrow absorption bandwidth. The main objective of this study is to obtain a wider sound absorption bandwidth by proposing an inhomogeneous perforation technique. The first step is to study the acoustic performance of a single layer MPP containing holes of two different sizes and ratios and with multiple cavity depths. Thereafter, for more improvement of the absorption bandwidth, this single MPP is cascaded with another single MPP to form a double-layer MPP model of inhomogeneous perforation. Mathematical models based on the equivalent electrical circuit method are proposed, and the absorption coefficient is calculated under a normal incidence of sound. The results show that the introduction of inhomogeneous perforation technique improves the absorption performance of the single layer MPP absorber compared to the homogenous one, especially with multi-cavity depths. The MPP layer should consist of two sets of perforation parameters set in an equal arrangement in two sub MPP areas; one of smaller perforation ratio with large hole diameter and the other of larger perforation ratio with smaller hole diameter. The proposed double layer inhomogeneous MPP model exhibits significantly wider sound absorption bandwidth and higher sound absorption amplitude than that of the conventional double-layer and even triple-layer homogeneous MPPs. The results demonstrate that the absorption bandwidth can be effectively controlled to higher frequencies region by reducing the air cavity between the two inhomogeneous MPP layers, and by decreasing the cavity depth behind the sub-MPP with small hole diameter and high perforation ratio. For the low frequency improvement, this can be achieved by increasing the cavity depth behind the sub-MPP with large hole diameter-small perforation ratio. The theoretical results were validated with the experiments by using the impedance tube method with a good agreement. This study also presents an empirical mathematical model for the single layer, multi cavity inhomogeneous MPP to conveniently obtain the required MPP parameters to have the halfabsorption bandwidth of absorption coefficient

Wideband Sound Absorption Of A Double-Layer Microperforated Panel With Inhomogeneous Perforation

Micro-perforated panel (MPP) absorber is increasingly gaining popularity as an alternative sound absorber in buildings compared to the well-known synthetic porous materials. A single MPP has a typical feature of a Helmholtz resonator with a high amplitude of absorption but a narrow absorption frequency bandwidth. To improve the bandwidth, a single MPP can be cascaded with another single MPP to form a double-layer MPP. This paper proposes the introduction of inhomogeneous perforation in the double-layer MPP system (DL-iMPP) to enhance the absorption bandwidth of a double-layer MPP. Mathematical models are proposed using the equivalent electrical circuit model and are validated with experiments with good agreement. It is revealed that the DL-iMPP produces a wider half-absorption bandwidth compared to the conventional homogeneous double-layer MPP. The absorption bandwidth to higher frequencies can be effectively controlled by reducing the air cavity between the iMPPs and to the lower frequencies by increasing the back cavity depth at the second layer

Theoretical Model Of Absorption Coefficient Of An Inhomogeneous MPP Absorber With Multi-Cavity Depths

Micro-perforated panel (MPP) absorber has been known as an alternative absorber to classical porous material given its facile installation, long durability, environmental friendliness and attractive appearance. Extensive studies of MPP absorber proposing the improvement of its absorption frequency bandwidth have been published. This study presents a MPP absorber introduced with inhomogeneous perforations and with multi-cavity depths. The MPP is divided into two sub-area, where each area has different hole diameter, perforation ratio and a separated backed cavity depth. The acoustic impedance is modelled using electrical equivalent circuit and the absorption coefficient is calculated under normal-incidence of sound. It is found that the inhomogeneous MPP can have good bandwidth of absorption by designing the sub-MPP of smaller perforation ratio with large hole diameter and the one having the larger perforation ratio with smaller hole diameter. The absorption bandwidth can be conveniently controlled by adjusting the cavity depth of each sub-MPP. The results from the experimental work show good agreement with the theoretical model

Echocardiographic Assessment Of Left Ventricular Systolic Function Among Patients with Chronic Kidney Disease Managed In Ebn Sena Dialysis Center In Diyala

Background: Cardiovascular diseases are prevalent in patients with chronic  kidney disease and represent the major hazard for mortality in this population . Left ventricular hypertrophy is a cardiovascular complication in patients with chronic kidney disease and end-stage renal disease. Left ventricular hypertrophy in dialysis patients has generally a bad prognostic value, because it represents a risk factor for the development of cardiac arrhythmias, ischemic heart disease, heart failure and sudden death. Objective: To study  left ventricular systolic functions by Echocardiography in patients with chronic renal failure on hemodialysis  program and their relation with some risk factors. Patients and Methods: 100 patients with end stage renal failure on dialysis were studied  by echocardiography, the patients were divided into two groups, the first group   with normal echo study , while the second group consisted of patients with left ventricular  systolic dysfunction. Risk factors  including age , sex , duration of dialysis , hypertension, DM, and hemoglobin levels were compared between the groups. Results: Left Ventricular  disorders occurred in 65% , 34% of patients showed left  ventricular  systolic dysfunction , , older age  group, longer duration of dialysis  , hypertension ,DM, and anemia were found to be significantly associated  with  left ventricular systolic dysfunction. Conclusion: Our study concluded that large numbers of end-stage renal disease patients have hypertension and diabetes as the etiology of their disease, which could be prevented by better approach in controlling blood pressure and blood sugar.         Anaemia is a major problem and as a predictor of cardiovascular risk factor for those patients. Echocardiographic Left Ventricular Study are prognostic predictors in chronic kidney disease patients, which suggest that echocardiography may play a vital role in assessing cardiac morphology and functions in those patients

Sound Absorption Of MPP With Irregular Hole Distribution

Analytical models for the sound absorption coefficient of MPP are extensively available particularly for the cases where holes are regularly distributed across the MPP structure. The behaviors of sound absorption performance have therefore been well recognized. Thus, it’s also interesting to study the MPP for the cases where the distribution of holes is not spaced regularly across the MPP, which becomes the objective of this paper. Here, the FEM is employed to simulate the acoustic impedance of the panel holes. Two main cases of irregular hole distributions are observed, namely 1) where the holes are concentrated in the middle of the plate, and 2) where the holes are distributed around the edge. For each case, this is applied for MPP with homogenous and inhomogeneous perforations. The analysis reveals that for both cases of hole distributions, the peak absorption can shift to lower frequency with the second case to have more effect than the first case. The finite element models are validated with experiment with good agreement

Effect of Intravenous Dexmedetomidine Infusion on Interleukin-6 (IL-6) and Plasma Cortisol in Open Heart Surgery

Aim of the work: to evaluate the effect of intravenous dexmedetomidine infusion on patients undergoing open heart surgery regarding stress response markers as plasma interleukin-6 and plasma cortisol. Patents and Methods: Fifty consecutive patients aged 18-70years, scheduled for elective open heart surgery using CPB technique were enrolled in this study at the Cardiothoracic Surgery Unit, Luxor international hospital, from July 2018 to May 2019. Patients randomly assigned using closed envelope technique into two equal groups according to the drug infused intraoperatively: 1st group (25 patients):- Dexmedetomidine group (Group D); received loading dose of intravenous dexmedetomidine infusion of 1 μg/kg IV dissolved in 20ml normal saline over 10 minutes followed by maintenance dose of 0.5 μg/kg/hr. till the end of surgery where 0.5 μg /kg/h was calculated for each patient and dissolved in 12.5 ml normal saline 2nd group ( 25 patients):- placebo group (Group P); receive 20ml intravenous infusion of normal saline 0.9 % over 10 minutes followed by continuous infusion of 12.5 ml of normal saline till the end of surgery. Results: Our study revealed that HR and MAP wasn’t significantly different between the two groups at the baseline, but significantly lowered in Dex. group after induction, during CPB, post CPB, and postoperative.Dexometomedine suppress the intraoperative and postoperative rise of IL-6 which was significantly higher in placebo group relative to Dex. group. Also dexometomedine has effect on stress hormone as serum cortisol and serum glucose decease in Dex. group relative to placebo group. None of studied cases revealed bradycardia or hypotention and there are no significant difference between groups regarding side effect drowsiness, nausea and vomiting Conclusion: This study demonstrated that the continuous administration of dexmedetomidine during open heart surgery with CPB suppressed intraoperative and post-operative cytokine secretion, and improved post-operative inflammatory response indices in the present study. Also it stabilize blood pressure and heart rate and blunt cardiovascular response to CPB. These results could be attributed to the anti-inflammatory effects of dexmedetomidine

The Promise of Molecular and Genomic Techniques for Biodiversity Research and DNA Barcoding of the Arabian Peninsula Flora

The Arabian Peninsula is known to have a comprehensive and rich endowment of unique and genetically diverse plant genetic resources. Analysis and conservation of biological diversity is a crucial issue to the whole Arabian Peninsula. The rapid and accurate delimitation and identification of a species is crucial to genetic diversity analysis and the first critical step in the assessment of distribution, population abundance and threats related to a particular target species. During the last two decades, classical strategies of evaluating genetic variability, such as morphology and physiology, have been greatly complemented by phylogenetic, taxonomic, genetic diversity and breeding research molecular studies. At present, initiatives are taking place around the world to generate DNA barcode libraries for vascular plant flora and to make these data available in order to better understand, conserve and utilize biodiversity. The number of herbarium collection-based plant evolutionary genetics and genomics studies being conducted has been increasing worldwide. The herbaria provide a rich resource of already preserved and identified material, and these as well as freshly collected samples from the wild can be used for creating a reference DNA barcode library for the vascular plant flora of a region. This review discusses the main molecular and genomic techniques used in plant identification and biodiversity analysis. Hence, we highlight studies emphasizing various molecular techniques undertaken during the last 10 years to study the plant biodiversity of the Arabian Peninsula. Special emphasis on the role of DNA barcoding as a powerful tool for plant biodiversity analysis is provided, along with the crucial role of herbaria in creating a DNA barcode library

Absorption Coefficient Of A Double-Layer Inhomogeneous Micro-Perforated Panel Backed With Multiple Cavity Depths

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 result

Cutaneous actinomycosis and long-term management through using oral and topical antibiotics: A case report

Actinomycosis is a subacute or chronic suppurative bacterial infection which caused because of filamentous gram-positive, anaerobic to microaerophilic nonacid fast bacilli primarily of the genus Actinomyces that normally colonize the mouth, colon, and vagina. Primary cutaneous actinomycosis is a rare entity and is generally associated with trauma. A 61- year-old Yemeni male firstly presented to the surgical department in King Fahd Central Hospital with multiple swelling, petted lesions and boring of sensation in the right foot. Local examination showed multiple erythematous nodules and plaques with discharge in the right leg, and active sinus was not determined

The impact of medication therapy management services on patient outcomes

This extensive analysis investigates the influence of Medication Therapy Management (MTM) services on patient outcomes, specifically emphasizing medication adherence, health-related quality of life, healthcare usage, and cost savings. We performed a comprehensive review and meta-analysis of relevant literature over the last decade to assess the efficacy of MTM services. The study included research that encompassed a wide range of patient demographics, with particular emphasis on individuals with chronic ailments and the elderly. The analysis demonstrated that MTM interventions had a substantial impact on enhancing drug adherence, leading to a noteworthy 10% rise in adherence rates when compared to conventional treatment. Moreover, MTM services have shown beneficial impacts on the health-related quality of life, especially in patients with chronic ailments like diabetes and hypertension. Patients who received MTM services reported enhanced physical and mental health ratings, suggesting a more extensive influence on their overall well-being. Furthermore, it was shown that MTM services effectively decrease healthcare consumption, resulting in a decrease in hospitalizations and trips to the emergency room. Significantly, those suffering from heart failure and numerous chronic ailments saw a noteworthy 20% decline in hospitalizations and a 15% drop in visits to the emergency room, respectively.&nbsp