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.
The moon tree, the lover of the night, cholera, the sea changes its colors are poetic products left by the pioneer of free poetry, as many have called her. She used to write poetry and publish it in magazines and newspapers until she published it with collections that came into existence from an early age. Several factors helped her in that that contributed to the formation of her personality and the maturity of her talent, including factors Family, including environmental, and psychological, until she later became the focus of attention of many, so she became taught in the universities of London, and students stood by her method of writing free poetry, this poetic color that Badr Shaker Al-Sayyab participated in pioneering. Whoever exam
... Show MoreBackground: Swine influenza (also Called pig influenza, swine flu, hog flu and pig flu) is an infection by any one of several types of swine influenza virus (SIV) or S-OIV (Swine-Origin influenza virus) is any strain of the influenza family of viruses that is endemic in pigs. Patients and Methods:- Ninety patients with there families suspected of swine flu who were admitted to Central Teaching Hospital of Pediatric in Baghdad seventy one from Baghdad Al-Kerkh, twelve from Baghdad Al-Rasafa and seven other Iraqi Governorate (1 in Suleimaniya, 2 in Baquba, 4 in Anbar) they were included in a prospective study started from the 1st October till the 30 th of November 2009. Results:- The study revealed from )90( suspected cases the H1N1 Virus Pos
... Show MoreAbstract Software-Defined Networking (commonly referred to as SDN) is a newer paradigm that develops the concept of a software-driven network by separating data and control planes. It can handle the traditional network problems. However, this excellent architecture is subjected to various security threats. One of these issues is the distributed denial of service (DDoS) attack, which is difficult to contain in this kind of software-based network. Several security solutions have been proposed recently to secure SDN against DDoS attacks. This paper aims to analyze and discuss machine learning-based systems for SDN security networks from DDoS attack. The results have indicated that the algorithms for machine learning can be used to detect DDoS
... Show MoreThe major objective of this study is to establish a network of Ground Control Points-GCPs which can use it as a reference for any engineering project. Total Station (type: Nikon Nivo 5.C), Optical Level and Garmin Navigator GPS were used to perform traversing. Traversing measurement was achieved by using nine points covered the selected area irregularly. Near Civil Engineering Department at Baghdad University Al-jadiriya, an attempt has been made to assess the accuracy of GPS by comparing the data obtained from the Total Station. The average error of this method is 3.326 m with the highest coefficient of determination (R2) is 0.077 m observed in Northing. While in
Abstract The avulsion of the flexor digitorum profundus, also known as the jersey finger, is a well-known injury that can be treated surgically. It has been classified into four types, among them type IV which involves tendon avulsion from an associated bony fragment with subsequent retraction to the palm or proximal interphalangeal joint is very rare. We present a case of type IV injury in a 45-year-old man with a pulling-on injury. The repair followed a pull-out technique (reinserting the tendon into the avulsed fragment); the entire reduction was tied over a button on the dorsal aspect of the nail and was augmented with a volar plate. The case was reported due to its rarity. We found that early surgical management of this problem greatly
... Show MoreIn this work, we focused on studying 1,4-naphthoquinones and their derivatives, and knowing the methods of preparing them using different auxiliary agents and forming derivatives containing heterocyclic rings, active groups and saturated rings containing heterogeneous elements . In addition, due to their strong antibacterial, antifungal and anticancer activity, 1,4-naphthoquinone compounds biological importance and are considered a source of various pharmaceutical compounds.
500 samples of diarrhea stool were collected from different ages(less than 1year –upto30years) and for both genders from some patients in (Alwiya hospital for children, Al-kendi, central health public laboratory and some gavernarated labs) period(1/11/2009—1/10/2010). Kinds of bacteria and parasites agents were isolated and identified from patients with diarrhea. Nine species of gram negative bacteria from enterobacteriaceae were isolated, E. coli isolated are the higher ratio 4.8% of all, then Salmonella typhi4.6% while the lowest ratios is Citrobacterfreundii 0.4%, while the other identified species were be among the previous rotios. also Plesomonasshigelloides was isolated which concedride one of the bacterial local studies.many met
... Show MoreBackground: In the past, an association between Tuberculosis (TB) and Diabetes Mellitus (DM) was widely accepted, today the potential public health and clinical importance of this relationship seems to be largely ignored. The national clinical and policy guidance in the UK on the central of TB, for example, does not consider the relationship with DM.Objectives: To determine the risk of association between diabetes mellitus and pulmonary TB.Methods: A retrospective study conducted in Ibn Zuhr hospital for chest diseases from Jan 2008 – sep 2010 , included in the study 402 patients with TB divided into diabetic & non diabetic, 96 (23.8%) were diabetic while other 306 were TB not diabetic.Results: Risk of TB among DM patients were cle
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