scholarly journals Highly Sensitive Photoacoustic Microcavity Gas Sensor for Leak Detection

Sensors ◽  
2020 ◽  
Vol 20 (4) ◽  
pp. 1164 ◽  
Author(s):  
Ke Chen ◽  
Yewei Chen ◽  
Bo Zhang ◽  
Liang Mei ◽  
Min Guo ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Gas Sensor ◽  
Second Harmonic ◽  
Low Cost ◽  
Side Wall ◽  
Leak Detection ◽  
Micro Electro Mechanical System ◽  
Stainless Steel Capillary ◽  
Highly Sensitive ◽  
Mems Microphone

A highly sensitive photoacoustic (PA) microcavity gas sensor for leak detection is proposed. The miniature and low-cost gas sensor mainly consisted of a micro-electro-mechanical system (MEMS) microphone and a stainless-steel capillary with two small holes opened on the side wall. Different from traditional PA sensors, the designed low-power sensor had no gas valves and pumps. Gas could diffuse into the stainless-steel PA microcavity from two holes. The volume of the cavity in the sensor was only 7.9 μL. We use a 1650.96 nm distributed feedback (DFB) laser and the second-harmonic wavelength modulation spectroscopy (2f-WMS) method to measure PA signals. The measurement result of diffused methane (CH4) gas shows a response time of 5.8 s and a recovery time of 5.2 s. The detection limit was achieved at 1.7 ppm with a 1-s lock-in integral time. In addition, the calculated normalized noise equivalent absorption (NNEA) coefficient was 1.2 × 10−8 W·cm−1·Hz−1/2. The designed PA microcavity sensor can be used for the early warning of gas leakage.

scholarly journals Miniaturized Thermal Acoustic Gas Sensor Based on a CMOS Microhotplate and MEMS Microphone

Proceedings ◽  
2020 ◽  
Vol 56 (1) ◽  
pp. 3
Author(s):  
Richard Hopper ◽  
Daniel Popa ◽  
Vasileios Tsoutsouras ◽  
Florin Udrea ◽  
Phillip Stanley-Marbell
Keyword(s):  
Physical Properties ◽  
Gas Sensor ◽  
Conversion Efficiency ◽  
Low Cost ◽  
Cmos Technology ◽  
Gas Detection ◽  
Co2 Gas ◽  
Sensing Mechanism ◽  
Mems Microphone

In this work, we present a novel thermal acoustic gas sensor, fabricated using a CMOS microhotplate and MEMS microphone. The sensing mechanism is based on the detection of changes in the thermal acoustic conversion efficiency which is dependent on the physical properties of the gas. The gas sensor has all the benefits of CMOS technology, including low cost and miniaturization. Here, we demonstrate its application for CO2 gas detection.

Low-Cost Underwater Sound Recorder for coastal applications.

2020 ◽  
Author(s):  
Valentina Cafaro ◽  
Andrea Terribili ◽  
Lorenzo Pasculli ◽  
Viviana Piermattei ◽  
Marco Marcelli ◽  
...  
Keyword(s):  
Data Quality ◽  
High Performance ◽  
Low Cost ◽  
Sensory Modality ◽  
Field Tests ◽  
Standard Technique ◽  
Micro Electro Mechanical System ◽  
Wide Frequency Range ◽  
Underwater Sound ◽  
Mems Microphone

<p>Sound is the most widespread and pervasive kind of anthropogenic energy that human activities introduce into the marine environment. Sound energy input can be highly variable both in time and space, becoming an important part of the total ocean acoustic background. Moreover, the underwater sound plays an ecologically important role in marine ecosystems, being a critical sensory modality for many marine organisms that can be useful for both sensing the environment and communication. With the Marine Strategy Framework Directive (MSFD) (2008/56/EC, EU 2008), underwater noise has been recognized as pollution and included in the qualitative high-level descriptors to achieve good environmental status, GES.</p><p>During recent years, passive acoustic monitoring in the ocean has become a standard technique across the oceanographic community and is used to address biological, geological and meteorological issues. Due to the highly spatio-temporal variability of the ocean noise, a large number of the observing systems would be needed. Extended marine monitoring would require a reduction in the cost of platforms and instruments, without compromising data quality. Despite, a significant effort has been invested by the scientific community in the development of low-cost PAM recorders, much work still remains. Most of the problems are related to the pressure to which the devices are exposed, the battery pack limits, storage memory limits, and sensibility of the sound sensor once waterproofing and so on.</p><p>Here, we present a low-cost underwater sound recorder for coastal applications developed to be applied in both background noise monitoring and bioacoustic monitoring. This recorder consists of a high-performance USB-based microcontroller development system with an audio adapter that guarantees high audio quality. Additionally, test were conducted using both an ECM (Electret Condenser Microphone) and a MEMS microphone (Micro-Electro-Mechanical System) for a wide frequency range recordings to find the better solutions for good data quality. Compact and small in size, it can be easily installed on various oceanographic platforms for different types of sampling.</p><p>Here we present the first results of the laboratory and field tests, comparing our assembled device with a commercial recorder and a pre-calibrated hydrophone.  </p>

UNS S41003

Alloy Digest ◽  
2001 ◽  
Vol 50 (1) ◽  
Keyword(s):  
Stainless Steel ◽  
Physical Properties ◽  
Tensile Properties ◽  
Martensitic Stainless Steel ◽  
Low Cost ◽  
Heat Treating ◽  
Bend Strength

Abstract UNS S41003 is a low-cost utilitarian martensitic stainless steel to be used for highway and other applications. It is used in the tempered condition at several strength levels. This datasheet provides information on composition, physical properties, elasticity, tensile properties, and shear and bend strength It also includes information on forming, heat treating, and joining. Filing Code: SS-815. Producer or source: Bethlehem Lukens Plate.

OUTOKUMPU MODA 410L/4003

Alloy Digest ◽  
2020 ◽  
Vol 69 (12) ◽  
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Physical Properties ◽  
Tensile Properties ◽  
Ferritic Stainless Steel ◽  
Low Cost ◽  
Heat Treating ◽  
Low Carbon ◽  
Alloy Steels ◽  
Corrosive Environments

Abstract Outokumpu Moda 410L/4003 is a weldable, extra low carbon, Cr-Ni, ferritic stainless steel that is best suited for mildly corrosive environments such as indoors, where the material is either not exposed to contact with water or gets regularly wiped dry, or outdoors, where some discoloration and superficial rusting are acceptable. It is a low-cost alternative to low-carbon non-alloy steels in certain applications. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SS-1330. Producer or source: Outokumpu Oyj.

DURACORR

Alloy Digest ◽  
1997 ◽  
Vol 46 (5) ◽  
Keyword(s):  
Fracture Toughness ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
Life Cycle ◽  
Physical Properties ◽  
Tensile Properties ◽  
Life Cycle Cost ◽  
Low Cost ◽  
Bend Strength ◽  
Steel Company

Abstract Duracorr is low-cost, utilitarian 11% Cr stainless steel with more corrosion resistance and life-cycle cost advantages than weathering steels. The steel may be used where a combination of abrasion and corrosion resistance is required. This datasheet provides information on composition, physical properties, microstructure, hardness, tensile properties, and bend strength as well as fracture toughness. It also includes information on corrosion resistance as well as joining. Filing Code: SS-680. Producer or source: Lukens Steel Company.

Overcoming Gas Sampling Problems: Analysis of Volatiles Using Capillary Column Needles

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 643f-643
Author(s):  
Weimin Deng ◽  
Randolph M. Beaudry
Keyword(s):  
Stainless Steel ◽  
Capillary Column ◽  
Dependent Manner ◽  
Stainless Steel Capillary ◽  
Stainless Steel Needle ◽  
Injection Volume ◽  
Volatile Analysis ◽  
Gas Tight ◽  
Sampling Problems ◽  
Time Injection

Sampling factors that could affect gas chromatograph (GC) response for volatile analysis such as syringe pumping time, injection volume, needle length, temperature, and the type of volatile were investigated. Capillary GC column segments (steel and glass) were installed in gas-tight syringes and used as needles for volatile analysis. Standard stainless-steel needles were also used. Hexylacetate, ethyl-2-methylbutyrate, 6-methyl-5-hepten-2-one, and butanol standard were measured. The number of pumps required to maximize GC response for each needle–volatile combination was determined. Maximal GC response for hexylacetate using standard stainless steel, capillary glass, and capillary steel needles required 10, 20 and 30 pumps, respectively. However, for butanol measurement, the optimal syringe pump number was 5 to 10 for all needle types. The use of a capillary needle resulted in an increase in GC response in the range of 3- to 15-fold relative to a standard stainless steel needle. Injection volume affected GC response in a needle-and volatile-dependent manner. In no case did injection volume vs. GC response extrapolate through origin. The GC response for capillary column needles increased as temperature decreased. Capillary column needles may be useful tools for analysis of volatiles that readily partition into the column coating.

scholarly journals A rapid, accurate, scalable, and portable testing system for COVID-19 diagnosis

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Guanhua Xun ◽  
Stephan Thomas Lane ◽  
Vassily Andrew Petrov ◽  
Brandon Elliott Pepa ◽  
Huimin Zhao
Keyword(s):  
Limit Of Detection ◽  
Low Cost ◽  
High Volume ◽  
N Gene ◽  
Testing System ◽  
Target Sequence ◽  
One Pot ◽  
Sequence Detection ◽  
Highly Sensitive ◽  
Speed Accuracy

AbstractThe need for rapid, accurate, and scalable testing systems for COVID-19 diagnosis is clear and urgent. Here, we report a rapid Scalable and Portable Testing (SPOT) system consisting of a rapid, highly sensitive, and accurate assay and a battery-powered portable device for COVID-19 diagnosis. The SPOT assay comprises a one-pot reverse transcriptase-loop-mediated isothermal amplification (RT-LAMP) followed by PfAgo-based target sequence detection. It is capable of detecting the N gene and E gene in a multiplexed reaction with the limit of detection (LoD) of 0.44 copies/μL and 1.09 copies/μL, respectively, in SARS-CoV-2 virus-spiked saliva samples within 30 min. Moreover, the SPOT system is used to analyze 104 clinical saliva samples and identified 28/30 (93.3% sensitivity) SARS-CoV-2 positive samples (100% sensitivity if LoD is considered) and 73/74 (98.6% specificity) SARS-CoV-2 negative samples. This combination of speed, accuracy, sensitivity, and portability will enable high-volume, low-cost access to areas in need of urgent COVID-19 testing capabilities.

Highly sensitive ethanol gas sensor based on In2O3 spheres

Ionics ◽  
2021 ◽  
Author(s):  
Chao Shen ◽  
Ning Xu ◽  
Rongfeng Guan ◽  
Lu Yue ◽  
Wenhui Zhang
Keyword(s):  
Gas Sensor ◽  
Highly Sensitive

scholarly journals Immobilization of Pseudomonas aeruginosa static biomass on eggshell powder for on-line preconcentration and determination of Cr (VI)

2020 ◽  
Vol 18 (1) ◽  
pp. 303-313 ◽  
Author(s):  
Aamir Rasheed ◽  
Tahseen Ghous ◽  
Sumaira Mumtaz ◽  
Muhammad Nadeem Zafar ◽  
Kalsoom Akhter ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Low Cost ◽  
Colorimetric Detection ◽  
Time Flow ◽  
Highly Sensitive ◽  
Glass Column ◽  
On Line ◽  
Preconcentration Time ◽  
Ultra Trace

AbstractIn the present work, a novel continuous flow system (CFS) is developed for the preconcentration and determination of Cr (VI) using Pseudomonas aeruginosa static biomass immobilized onto an effective and low-cost solid support of powdered eggshells. A mini glass column packed with the immobilized biosorbent is incorporated in a CFS for the preconcentration and determination of Cr (VI) from aqueous solutions. The method is based on preconcentration, washing and elution steps followed by colorimetric detection with 1,5-diphenyl carbazide in sulphuric acid. The effects of several variables such as pH, retention time, flow rate, eluent concentration and loaded volume are studied. Under optimal conditions, the CFS method has a linear range between 10 and 100 μg L-1 and a detection limit of 6.25 μg L-1 for the determination of Cr (VI). The sampling frequency is 10 samples per hour with a preconcentration time of 5 mins. Furthermore, after washing with a 0.1 M buffer (pH 3.0), the activity of the biosorbent is regenerated and remained comparable for more than 200 cycles. Scanning electron microscopy reveals a successful immobilization of biomass on eggshells powder and precipitation of Cr (VI) on the bacterial cell surface. The proposed method proves highly sensitive and could be suitable for the determination of Cr (VI) at an ultra-trace level.

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