A wave-envelope of sound propagation in nonuniform circular ducts with compressible mean flows

An acoustic theory is developed to determine the sound transmission and attenuation through an infinite, hard-walled or lined circular duct carrying compressible, sheared, mean flows and having a variable cross section. The theory is applicable to large as well as small axial variations, as long as the mean flow does not separate. The technique is based on solving for the envelopes of the quasi-parallel acoustic modes that exist in the duct instead of solving for the actual wave, thereby reducing the computation time and the round-off error encountered in purely numerical techniques. The solution recovers the solution based on the method of multiple scales for slowly varying duct geometry. A computer program was developed based on the wave-envelope analysis for general mean flows. Results are presented for the reflection and transmission coefficients as well as the acoustic pressure distributions for a number of conditions: both straight and variable area ducts with and without liners and mean flows from very low to high subsonic speeds are considered

Transmission of sound through nonuniform circular ducts with compressible mean flows

An acoustic theory is developed to determine the sound transmission and attenuation through an infinite, hard-walled or lined, circular duct carrying compressible, sheared, mean flows and having a variable cross section. The theory is applicable to large as well as small axial variations, as long as the mean flow does not separate. Although the theory is described for circular ducts, it is applicable to other duct configurations - annular, two dimensional, and rectangular. The theory is described for the linear problem, but the technique is general and has the advantage of being applicable to the nonlinear case as well as the linear case. The technique is based on solving for the envelopes of the quasi-parallel acoustic modes that exist in the duct instead of solving for the actual wave. A computer program was developed. The mean flow model consists of a one dimensional flow in the core and a quarter-sine profile in the boundary layer. Results are presented for the reflection and transmission coefficients in ducts with varying slopes and carrying different mean flows

Thermal decomposition products of kynol and nomex with reference to structure and toxicity

The purpose of this investigation was to study the combustion products of KYNOL and NOMEX as a fire retardant fibers. From the quantitative analysis data of the combustion products, the polymer structure is discussed and the property of thermal stability is explained. From the analysis of the combustion products, the toxicity indices for the two fibers are determined. It is found to be 0.1 for KYNOL and 0.71 for NOMEX. This can be interpreted to mean that, if one gram of MIDI, is decomposed and the combustion products were diffused in one cubic meter of air, the probability of dying for a man in that space after 30 minutes exposure is only 10 %, while that of NOMEX is 71 %

Early outcome of pediatric pyeloplasty in kidneys with split renal function less than 10%: A prospective study of 25 cases

Objectives: To detect the outcome of pyeloplasty in kidneys with split renal function (SRF) less than 10% in the pediatric age group.Subjects and methods: We prospectively analyzed the data from 25 cases of ureteropelvic junction obstruction (UPJO) candidate for pyeloplasty with SRF less than 10%. Abdominopelvic ultrasonography and diuretic renogram using technetium-99 m diethylenetriamine Penta acetic acid (DTPA) were done in all cases. We studied the improvement in pelvic anteroposterior diameter (APD) postoperatively. We compared pre and postoperative SRF after six months and one year.Results: The median age was 24 months (3 months–11 years), male to female 2:1. The median preoperative SRF was 5% (range: 0%–10%) and the median APD of the renal pelvis was 3 cm (range: 2.2–5). There was significant improvement of median APD 0.8 cm (range: 0.5–1.9) (P value <0.05). There was a significant postoperative improvement in the median SRF (P-value <0.05) as the median SRF after 6 months and 1 year were 21% and 20%, respectively but there was no significant difference between SRF at six months and one year (P value 0.174).Conclusion: Pyeloplasty provides high rates of functional success even in very poorly functioning kidneys with SRF ≤10% by DTPA renogram in pediatric age group

The Plasma Interaction Experiment (PIX) description and test program

The plasma interaction experiment (PIX) is a battery powered preprogrammed auxiliary payload on the LANDSAT-C launch. This experiment is part of a larger program to investigate space plasma interactions with spacecraft surfaces and components. The varying plasma densities encountered during available telemetry coverage periods are deemed sufficient to determine first order interactions between the space plasma environment and the biased experimental surfaces. The specific objectives of the PIX flight experiment are to measure the plasma coupling current and the negative voltage breakdown characteristics of a solar array segment and a gold plated steel disk. Measurements will be made over a range of surface voltages up to plus or minus kilovolt. The orbital environment will provide a range of plasma densities. The experimental surfaces will be voltage biased in a preprogrammed step sequence to optimize the data returned for each plasma region and for the available telemetry coverage

Static stability of the Space Station solar array FASTMast structure

The combined loads test of the 3-Bay FASTMast marks the end of the Lewis Research Center (LeRC) effort to characterize the behavior of the principal Space Station solar array support structure. The primary objective of this test and analysis effort was to develop a method to predict structural stability failure modes under flight-like applied loads. Included at the beginning of this report is a brief historical perspective of the hardware design development and FASTMast structural stability problem evolution. Once an understanding of the solution process has been established, test and analysis details are presented and related to the postulated failure theories. The combined load test series subjected the structure to a combination of transverse, moment, and torsion loads similar to that expected in the service environment. Nonlinear finite element (FE) models were developed and large displacement analyses were performed to support the test effort and failure mode predictions. Details of the test configuration as well as test and analysis results are presented. The results were then critiqued to establish valid and successful support of the failure mode assessments. Finally, study conclusions are drawn and recommendations for safe operation of the FASTMast structure are presented for consideration

HILLE-KNESER-TYPE CRITERIA FOR SECOND-ORDER DYNAMIC EQUATIONS ON TIME SCALES

We consider the pair of second-order dynamic equations, (r(t)(xΔ)γ)Δ + p(t)xγ(t) = 0 and (r(t)(xΔ)γ)Δ + p(t)xγσ (t) = 0, on a time scale T, where γ \u3e 0 is a quotient of odd positive integers. We establish some necessary and sufficient conditions for nonoscillation of Hille-Kneser type. Our results in the special case when T = R involve the well known Hille-Kneser-type criteria of second-order linear differential equations established by Hille. For the case of the second-order half-linear differential equation, our results extend and improve some earlier results of Li and Yeh and are related to some work of Dosly and Rehak and some results of Rehak for half-linear equations on time scales. Several examples are considered to illustrate the main results

Technique for recognizing faces using a hybrid of moments and a local binary pattern histogram

The face recognition process is widely studied, and the researchers made great achievements, but there are still many challenges facing the applications of face detection and recognition systems. This research contributes to overcoming some of those challenges and reducing the gap in the previous systems for identifying and recognizing faces of individuals in images. The research deals with increasing the precision of recognition using a hybrid method of moments and local binary patterns (LBP). The moment technique computed several critical parameters. Those parameters were used as descriptors and classifiers to recognize faces in images. The LBP technique has three phases: representation of a face, feature extraction, and classification. The face in the image was subdivided into variable-size blocks to compute their histograms and discover their features. Fidelity criteria were used to estimate and evaluate the findings. The proposed technique used the standard Olivetti Research Laboratory dataset in the proposed system training and recognition phases. The research experiments showed that adopting a hybrid technique (moments and LBP) recognized the faces in images and provide a suitable representation for identifying those faces. The proposed technique increases accuracy, robustness, and efficiency. The results show enhancement in recognition precision by 3% to reach 98.78%

Oral verapamil in paroxysmal supraventricular tachycardia recurrence control: A randomized clinical trial

Background: Adenosine is the first-line medication in patients with paroxysmal supraventricular tachycardia. Because it is cleared so rapidly from the circulation, recurrence of paroxysmal supraventricular tachycardia after initial successful conversion may occur. This study was conducted to evaluate the role of oral verapamil administration to control early recurrences of paroxysmal supraventricular tachycardia after adenosine infusion. Methods: Patients with acute paroxysmal supraventricular tachycardia and no contraindications for adenosine or verapamil treatment were included in study. All patients received an adenosine protocol (6 mg rapid bolus intravenous injection followed by two repeated doses of 12 mg if necessary). Patients in the adenosine-only group did not received any other medications but patients in the adenosine/verapamil group received 40 mg verapamil orally immediately after converting the rhythm to sinus rhythm. All patients were followed up for 6 h in the acute care area of the emergency department under continuous cardiac monitoring. Results: A total of 113 patients were assessed for eligibility and 92 patients were randomized into two groups (adenosine only versus adenosine/verapamil). There was no statistically significant difference in paroxysmal supraventricular tachycardia recurrence rate between the two groups in the first 30 min after treatment. Recurrence rate was statistically significantly lower in the adenosine/verapamil group than in the adenosine-only group between 30 and 120 min after treatment and thereafter. Two patients in the adenosine-only group experienced flushing and one patient in the adenosine/verapamil group experienced decreased systolic blood pressure. Oral verapamil can decrease paroxysmal supraventricular tachycardia recurrence after successful control with intravenous adenosine. © 2014, SAGE Publications. All rights reserved

Biochemical Testing Revision For Identification Several Kinds of Bacteria

البكتيريا هي الجراثيم المسببة للأمراض التي تسبب مجموعة متنوعة من الأمراض لدى البشر ، تتراوح من الطفيفة إلى التي تهدد الحياة. مطلوب الاكتشاف المناسب للعامل البكتيري المسبب للمرض من أجل العلاج المناسب للمرضى المصابين بهذه الاضطرابات.           يتم تصنيف البكتيريا إلى مجموعتين: البكتيريا موجبة الجرام والبكتيريا سلبية الجرام. يحتوي كلا النوعين من البكتيريا على مجموعة متنوعة من السمات البيوكيميائية الموروثة التي تسمح لنا بتمييزها ، والتحقق من وجودها وغيابها ، وتحديد ما إذا كانت سالبة الجرام أو موجبة الجرام. نتيجة لذلك ، تركز المراجعة الحالية على وصف العديد من الاختبارات الكيميائية الحيوية في قطعة واحدة. الاسـتنـتاجات           يتم التعرف على البكتيريا موجبة الجرام باستخدام الاختبارات الكيميائية الحيوية مثل اختبار الكاتلاز ، واختبار تجلط الدم ، واختبار التحلل المائي للنشا ، واختبار النترات ، بينما يتم تحديد البكتيريا سالبة الجرام باستخدام الاختبارات الكيميائية الحيوية مثل اختبار أوكسيديز ، واختبار اليورياز ، واختبار إندول ، واختبار الكبريت ، و اختبار الميثيل الأحمر / voges-proskauer. تم إنشاء اختبار المؤشر التحليلي 20E للتمييز بين بكتيريا Enterbacteriacea سالبة الجرام والبكتيريا غير Enterbactriacea. تم أيضًا إنشاء ميكروبات موجبة الجرام مثل أنواع المكورات العنقودية وأنواع المكورات الدقيقة والكائنات الحية الأخرى ذات الصلة باستخدام طريقة API.Abstract:       Bacteria are pathogenic germs that cause a variety of diseases in humans, ranging from minor to life-threatening. Proper detection of the disease-causing bacterial agent is required for proper treatment of patients affected with these disorders. Bacteria are classified into two groups: Gram Positive Bacteria and Gram Negative Bacteria. Both types of bacteria have a variety of inherited biochemical traits that allow us to distinguish them, check for their presence and absence, and determine whether they are gram negative or gram positive. As a result, the current review focuses on describing many biochemical assays in a single piece. Conclusion           Gram positive bacteria are identified using biochemical tests such as the catalase test, coagulase test, starch hydrolysis test, and nitrate test, while Gram negative bacteria are identified using biochemical tests such as the oxidase test, urease test, indole test, sulfur test, and methyl red /voges-proskauer test. The analytical profile index test 20E was created to distinguish between Gram-negative Enterbacteriacea and non-Enterbactriacea bacteria. Gram-positive microbes such as Staphylococcus species, Micrococcus species, and other related organisms have also been generated using the API method