scholarly journals Research on “Cylinder-Four-Beam” Microstructure Improvement of MEMS Bionic Vector Hydrophone

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Zeming Jian ◽  
Yifan Huang ◽  
Lei Nie ◽  
Mengran Liu ◽  
Guojun Zhang
Keyword(s):  
Mechanical Analysis ◽  
Feasible Region ◽  
Performance Tests ◽  
Microstructural Parameters ◽  
Ansys Simulation ◽  
Block Height ◽  
Vector Hydrophone ◽  
Length Width ◽  
Low Sensitivity ◽  
Higher Sensitivity

The existing MEMS bionic vector hydrophone has the problems of low-sensitivity and narrow-working band, and the sensitivity and working bandwidth cannot be improved simultaneously by changing the single microstructural parameter. In this paper, the MEMS bionic vector hydrophone microstructural parameters (length, width and height of cantilever, side length of the center block, height and radius of the rigid cylinder) have been optimized simultaneously to obtain a higher sensitivity at the almost same working bandwidth. Firstly, through the mechanical analysis of the microstructure, the objective function and feasible region are established to optimize the parameters of the microstructure, and a set of optimized parameters is obtained. Secondly, the optimized structure is verified by ANSYS simulation, and then, the optimized four-beam structure is fabricated by the MEMS manufacturing technology. Finally, these two kinds of hydrophones (the previous one and the optimized one) are produced, and their performance tests are carried out. The testing results show that the performances of the optimized hydrophone have been greatly improved, exhibiting a receiving sensitivity of −181.2 dB@1 kHz (increasing by 6.5 dB, 0 dB reference 1 V/μ Pa), the frequency response ranging from 20 Hz to 1 kHz which is the same working bandwidth as before, and a good dipole directivity. The optimization researches in this paper provide a method and idea for the performance improvement of the following MEMS vector hydrophone.

scholarly journals Molecular Dynamics Simulation of the Influence of RDX Internal Defects on Sensitivity

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 329
Author(s):  
Pengmin Yan ◽  
Xue Zhao ◽  
Jiuhou Rui ◽  
Juan Zhao ◽  
Min Xu ◽  
...  
Keyword(s):  
Energetic Materials ◽  
Low Cost ◽  
Relative Sensitivity ◽  
Dynamics Simulation ◽  
Safety Properties ◽  
Internal Defects ◽  
X Ray ◽  
X Ray Computed ◽  
Low Sensitivity ◽  
Higher Sensitivity

The internal defect is an important factor that could influence the energy and safety properties of energetic materials. RDX samples of two qualities were characterized and simulated to reveal the influence of different defects on sensitivity. The internal defects were characterized with optical microscopy, Raman spectroscopy and microfocus X-ray computed tomography technology. The results show that high-density RDX has fewer defects and a more uniform distribution. Based on the characterization results, defect models with different defect rates and distribution were established. The simulation results show that the models with fewer internal defects lead to shorter N-NO2 maximum bond lengths and greater cohesive energy density (CED). The maximum bond length and CED can be used as the criterion for the relative sensitivity of RDX, and therefore defect models doped with different solvents are established. The results show that the models doped with propylene carbonate and acetone lead to higher sensitivity. This may help to select the solvent to prepare low-sensitivity RDX. The results reported in this paper are aiming at the development of a more convenient and low-cost method for studying the influence of internal defects on the sensitivity of energetic materials.

scholarly journals In Vitro Antimicrobial Sensitivity of Escherichia coli Isolated from Clinical Sources

1970 ◽  
Vol 34 (1) ◽  
pp. 99-101
Author(s):  
Mohammad Shahriar ◽  
Mahboob Hossain ◽  
Shaila Kabir
Keyword(s):  
Escherichia Coli ◽  
Nalidixic Acid ◽  
E Coli ◽  
Antimicrobial Sensitivity ◽  
Sensitivity Pattern ◽  
Low Sensitivity ◽  
Academy Of Sciences ◽  
Higher Sensitivity

A study of antimicrobial sensitivity of Escherichia coli (E. coli) isolated from clinical sourcesof different diagnostic centers of Dhaka, Bangladesh was carried out to facilitate the choice of drugin the management of E. coli induced symptoms. Very low sensitivity of E. coli towards ampicillin(4%), aztreonam (4%), cloxacillin (5%), nalidixic acid (5%), ciprofloxacin (7.5%), ceftriaxone(12.5%), doxycycline (12.5%), ceftazidime (16.25%), co-trimoxazole (20%), chloramphenicol(22.51%), tetracycline (25%), and netilmicin (35%) was observed. Higher sensitivity pattern wasobserved for gentamicin (56%) and only imipenem (95%) showed sensitivity pattern possiblysusceptible enough to consider for the management of E. coli induced cases in the area under study.The low sensitivity to different antimicrobial could be attributed to their prevailing usage and abusein the area under study.Key words: E. coli; Antimicrobial sensitivity; Clinical isolatesDOI: 10.3329/jbas.v34i1.5497Journal of Bangladesh Academy of Sciences, Vol.34, No.1, 99-101, 2010

The role of CT in the diagnosis of sacro-iliitis

1998 ◽  
Vol 39 (3) ◽  
pp. 265-268 ◽  
Author(s):  
M. Geijer ◽  
H. Sihlbom ◽  
J. H. Göthlin ◽  
E. Nordborg
Keyword(s):  
Clinical Symptoms ◽  
Conventional Radiography ◽  
Symptom Duration ◽  
Radiological Findings ◽  
Early Start ◽  
Early Course ◽  
Low Sensitivity ◽  
Higher Sensitivity ◽  
Made In

Objective: Ankylosing spondylitis is a progressive, debilitating disease in which early diagnosis and early treatment can improve the prognosis. Radiographic confirmation is essential for diagnosis but conventional radiography has not proved useful, particularly in the early course of the disease. The aims of this study were to correlate the findings at conventional radiography with those at CT, and to correlate the duration of clinical symptoms with the radiological findings Material and Methods: Forty patients with clinical sacro-iliitis and 13 controls were evaluated by means of conventional radiography and CT Results: Conventional radiography was positive in 10/40 patients and CT in 30/40 patients. Conventional radiography was positive in only 2/14 patients with a symptom duration of less than 2 years while CT was positive in 10/14 such patients Conclusion: The study demonstrated a considerably higher sensitivity in CT than in conventional radiography in detecting the subtle changes necessary for the radiological diagnosis of sacro-iliitis, particularly in cases of short duration. CT allows an early start to be made in treatment with a consequently improved prognosis. The use of conventional radiography cannot be recommended because its low sensitivity delays diagnosis in many instances

scholarly journals Lateral flow assays for diagnosing invasive pulmonary aspergillosis in adult hematology patients: A comparative multicenter study

2019 ◽  
Vol 58 (4) ◽  
pp. 444-452 ◽  
Author(s):  
Toine Mercier ◽  
Albert Dunbar ◽  
Elizabeth de Kort ◽  
Alexander Schauwvlieghe ◽  
Marijke Reynders ◽  
...  
Keyword(s):  
Invasive Pulmonary Aspergillosis ◽  
Lavage Fluid ◽  
Turnaround Time ◽  
Lateral Flow ◽  
Pulmonary Aspergillosis ◽  
Microbiological Methods ◽  
Lateral Flow Assays ◽  
Sample Testing ◽  
Low Sensitivity ◽  
Higher Sensitivity

Abstract Fast diagnosis of invasive pulmonary aspergillosis (IPA) is essential as early adequate therapy improves survival. However, current microbiological methods suffer from a low sensitivity or a long turnaround time, often as a result of batching. Recently, two lateral flow assays for diagnosing IPA have been CE (Conformité Européenne)-marked and commercialized. These assays can be used for fast single sample testing. However, clinical validation and comparative studies are lacking. We therefore sought to evaluate and compare these assays in adult hematology patients. We retrospectively tested 235 bronchoalveolar lavage fluid (BALf) samples of adult hematology patients from four centers using the AspLFD (OLM Diagnostics) and the sōna Aspergillus galactomannan LFA (IMMY). Both tests were read out independently by two researchers and by a digital reader. We included 11 patients with proven IPA, 64 with probable IPA, 43 with possible fungal disease, and 117 controls with no signs of IPA. In cases of proven IPA, the performance of both assays was similar. In cases of proven and probable IPA, we found an identical specificity for both assays, but a higher sensitivity (0.83 vs 0.69, P = .008) and a better negative predictive value (0.89 vs 0.82, P = .009) for the LFA. Digital readout improved the diagnostic performance of both tests. In conclusion, both assays showed a good performance for the diagnosis of IPA in BALf from adult hematology patients. Results were further improved by using a digital reader, especially for weakly positive results.

scholarly journals Contamination of River Water byCryptosporidium parvum Oocysts in Western Japan

2001 ◽  
Vol 67 (9) ◽  
pp. 3832-3836 ◽  
Author(s):  
Kazuo Ono ◽  
Hidetaka Tsuji ◽  
Shiba Kumar Rai ◽  
Akio Yamamoto ◽  
Kuniyoshi Masuda ◽  
...  
Keyword(s):  
River Water ◽  
Cryptosporidium Parvum ◽  
Fragment Length Polymorphism ◽  
Immunomagnetic Separation ◽  
Polymorphism Analysis ◽  
Western Region ◽  
Western Japan ◽  
Low Sensitivity ◽  
Bovine Type ◽  
Higher Sensitivity

ABSTRACT In Japan, only a few rivers have been inspected forCryptosporidium parvum contamination, and the methods used had low sensitivity. In 1998 and 1999, we used a method with higher sensitivity to examine all large rivers used as sources of water supply in one prefecture (which we divided into four areas) in western Japan for Cryptosporidium oocysts. One sample was collected at each of 156 sites along 18 rivers, and samples were tested for Cryptosporidium oocysts by immunomagnetic separation. Samples were classified as being obtained on an island with livestock and fishing industries, a densely populated urban area, a western region including farming villages, or a still more rural northern area with agriculture and fishing. Restriction fragment length polymorphism analysis was used for identification of the C. parvum found as the bovine or human type. C. parvum was detected in at least one sample from 13 of the 18 rivers and in 47% (74 of 156) of the samples. One-third to all of the samples from each area contained C. parvum oocysts. The number of C. parvum oocysts per 20 liters of river water varied in the same pattern as the number of cattle kept in the four kinds of areas (as determined by the Mantel extension test). Oocysts isolated were of the bovine type; the C. parvum detected in rivers probably came from cattle kept in that valley. As we had expected, when tested with a more sensitive method, river water in western Japan was found to be greatly contaminated with C. parvum oocysts, as reported in other countries.

scholarly journals Sensitivity Analysis of a Bayesian Network

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Chenzhao Li ◽  
Sankaran Mahadevan
Keyword(s):  
Sensitivity Analysis ◽  
Bayesian Network ◽  
Prior Distribution ◽  
Global Sensitivity Analysis ◽  
Auxiliary Variable ◽  
Sensitivity Index ◽  
Main Concern ◽  
Deterministic Function ◽  
Low Sensitivity ◽  
Higher Sensitivity

In a Bayesian network (BN), how a node of interest is affected by the observation at another node is a main concern, especially in backward inference. This challenge necessitates the proposed global sensitivity analysis (GSA) for BN, which calculates the Sobol’ sensitivity index to quantify the contribution of an observation node toward the uncertainty of the node of interest. In backward inference, a low sensitivity index indicates that the observation cannot reduce the uncertainty of the node of interest, so that a more appropriate observation node providing higher sensitivity index should be measured. This GSA for BN confronts two challenges. First, the computation of the Sobol’ index requires a deterministic function while the BN is a stochastic model. This paper uses an auxiliary variable method to convert the path between two nodes in the BN to a deterministic function, thus making the Sobol’ index computation feasible. Second, the computation of the Sobol’ index can be expensive, especially if the model inputs are correlated, which is common in a BN. This paper uses an efficient algorithm proposed by the authors to directly estimate the Sobol’ index from input–output samples of the prior distribution of the BN, thus making the proposed GSA for BN computationally affordable. This paper also extends this algorithm so that the uncertainty reduction of the node of interest at given observation value can be estimated. This estimate purely uses the prior distribution samples, thus providing quantitative guidance for effective observation and updating.

scholarly journals Preparation and thermal insulation performance of cast-in-situ phosphogypsum wall

2018 ◽  
Vol 16 (1_suppl) ◽  
pp. 81-92
Author(s):  
Yubo Li ◽  
Shaobin Dai ◽  
Yichao Zhang ◽  
Jun Huang ◽  
Ying Su ◽  
...  
Keyword(s):  
Thermal Insulation ◽  
Green Building ◽  
Building Construction ◽  
Sound Insulation ◽  
Performance Tests ◽  
Method Of Calculation ◽  
Ansys Simulation ◽  
Insulation Performance ◽  
The Heat Transfer Coefficient

Introduction: The mass accumulation of phosphogypsum has caused serious environmental pollution, which has become a worldwide problem. Gypsum is a kind of green building material, which is lighter, has better heat and sound insulation performance, and is easier to recycle compared to cement. The application of cast-in-situ phosphogypsum wall could consume a large amount of pollutant, and improve the efficiency of building construction. Methods: The preparation and thermal insulation performance of cast-in-situ phosphogypsum wall were investigated. The property of phosphogypsum–fly ash–lime (PFL) triad cementing materials, the adaptability of retarders and superplasticizers, and the influences of vitrified microsphere as aggregates were explored. Thus, the optimum mix was proposed. Thermal insulation performance tests and ANSYS simulation of this material was carried out. Results: Optimal structures based on heat channels and the method of calculation determining related parameters were proposed, which achieved a 12.3% reduction in the heat transfer coefficient of the wall. Conclusion: With good performance, phosphogypsum could be used in cast-in-situ walls. This paper provides the theoretical basis for the preparation and energy-saving application of phosphogypsum in the walls of buildings.

Tu1426 The ROME III Adult Questionnaire in Spanish-Mexico Has a Low Sensitivity for Identifying IBS and Higher Sensitivity for Uninvestigated Dyspepsia

2012 ◽  
Vol 142 (5) ◽  
pp. S-829-S-830 ◽  
Author(s):  
Max J. Schmulson ◽  
Aurelio Lopez-Colombo ◽  
Analy Mendoza-Gomez ◽  
Alvaro Montiel-Jarquin ◽  
Douglas R. Morgan
Keyword(s):  
Rome Iii ◽  
Low Sensitivity ◽  
Higher Sensitivity

scholarly journals Military Multipurpose Pylon Deigned for 100tf Load

2016 ◽  
Vol 22 (3) ◽  
pp. 670-676
Author(s):  
Adrian Popa ◽  
Ionuţ-Cristian Scurtu ◽  
Beazit Ali ◽  
Marian Ristea
Keyword(s):  
Complex Analysis ◽  
Emerging Technologies ◽  
Mechanical Analysis ◽  
Specific Load ◽  
Ansys Software ◽  
Ansys Simulation ◽  
Military Applications ◽  
Working Parameters ◽  
The Military

Abstract The breakthrough in static structural, buckling and modal computer-simulated results can be used for new military purpose applications. The development of hardware resources leads to better simulation in mechanical analysis. Based on the Ansys software, the values presented for the pylon result from a complex analysis. The present paper aims at defining the working parameters for a specific load of 100 tf, as well as presenting the actual software capabilities for military applications. The information provided is valuable for the emerging technologies and the military techniques, being based on the ANSYS simulation.

scholarly journals Comparison of Xpert MTB/RIF Assay and the Conventional Sputum Microscopy in DetectingMycobacterium tuberculosisin Northern Thailand

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Kanokwan Pinyopornpanish ◽  
Romanee Chaiwarith ◽  
Chansom Pantip ◽  
Rassamee Keawvichit ◽  
Kanlaya Wongworapat ◽  
...  
Keyword(s):  
Pulmonary Tuberculosis ◽  
Cross Sectional Study ◽  
University Hospital ◽  
Sputum Smear ◽  
Cross Sectional ◽  
Sputum Microscopy ◽  
Lower Specificity ◽  
Negative Sputum ◽  
Low Sensitivity ◽  
Higher Sensitivity

Background.Despite low sensitivity in detection ofMycobacterium tuberculosis, sputum acid-fast smear remains the main diagnostic method. This study aimed to compare the diagnostic performance of Xpert MTB/RIF assay versus conventional sputum acid-fast smear.Materials and Methods.A cross-sectional study was conducted at Chiang Mai University Hospital, Thailand. Patients who were ≥15 years old and had clinically suspected pulmonary tuberculosis were included.Results.109 specimens from 57 patients were included. Using MGIT sputum culture as a reference standard, the sensitivity (SEN) and specificity (SPEC) for Xpert were 95.3% (95% CI, 84.2%, 99.4%) and 86.4% (95% CI, 75.7%, 93.6%). The SEN and SPEC for sputum acid-fast smear were 60.5% (95% CI, 44.4%, 75.0%) and 98.5% (95% CI, 91.8%, 100%). Xpert had significantly higher sensitivity (pvalue < 0.001) and lower specificity (pvalue = 0.022) than sputum acid-fast smear. Among 43 culture-provenM. tuberculosisspecimens, sensitivity of Xpert was 100% (95% CI, 86.7%, 100%) in acid-fast positive smears (n=26) and 88.2% (95% CI, 63.5%, 98.5%) in acid-fast negative smears (n=17).Conclusions.The good sensitivity and specificity of Xpert assay in detectingM. tuberculosisfrom sputum specimens may help in early diagnosis and treatment of pulmonary tuberculosis, particularly among patients who had acid-fast negative sputum smear.

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