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Pd/Ag alloy as an application for hydrogen sensing
Sharma, Bharat,Kim, Jung-Sik Elsevier 2017 International journal of hydrogen energy Vol.42 No.40
<P><B>Abstract</B></P> <P>A highly sensitive H<SUB>2</SUB> gas sensor was fabricated using a Micro Electromechanical Systems (MEMS) procedure having an embedded micro-heater. The palladium-silver (Pd/Ag having stoichiometric ratios 77:23) thin film was deposited by the RF/DC magnetron sputtering and used as the hydrogen sensing layer designed as a zig-zag pattern. Morphological and structural properties of the Pd/Ag thin film was studied by Field emission scanning electron microscope (FESEM), Atomic force microscopy (AFM) and Energy Dispersive Analysis of X-rays respectively. The working temperature of the micro heater showed a linear relation with variations of the heater voltage. The electro thermal properties of the H<SUB>2</SUB> sensor were studied by finite element method (FEM). The sensing properties of the fabricated H<SUB>2</SUB> sensor as the change of electrical resistance were studied with respect to hydrogen concentration and temperature. Experimental results showed high sensor response and response time after application of the heater voltage. The sensing properties of the alloyed Pd/Ag thin film were more improved than those of pure palladium. The maximum sensor response (R<SUB>s</SUB>) of the fabricated H<SUB>2</SUB> sensor was 14.26% for 1000 ppm H<SUB>2</SUB>. The sensor response of the fabricated H<SUB>2</SUB> sensor showed linear behavior with the heater voltage (operating temperature) and positively corresponded with the hydrogen concentration.</P> <P><B>Highlights</B></P> <P> <UL> <LI> MEMS based gas sensor was fabricated for H<SUB>2</SUB> sensing (embedded micro-heater). </LI> <LI> Pd/Ag alloy thin film used as the hydrogen sensing layer with a zig-zag pattern. </LI> <LI> Working temperature of micro heater shows a linear relation with heater voltage. </LI> <LI> The max. sensor response of the fabricated H<SUB>2</SUB> sensor was 14.26% for 1000 ppm H<SUB>2</SUB>. </LI> <LI> Sensor response of H<SUB>2</SUB> sensor shows linear behavior with heater voltage and H<SUB>2</SUB> conc. </LI> </UL> </P>
Recent advances on H<sub>2</sub> sensor technologies based on MOX and FET devices: A review
Sharma, Bharat,Sharma, Ashutosh,Kim, Jung-Sik Elsevier 2018 Sensors and actuators. B Chemical Vol.262 No.-
<P><B>Abstract</B></P> <P>The importance of metal oxide semiconductor (MOX) and field effect transistor (FET) based sensors has been increasing due to their extended practical applications for gas detection. Various investigations have confirmed that gas sensing characteristics depend on the sensitivity of the metal oxide and catalytic materials. In recent years, hydrogen gas sensor technology has been progressively more capable in practical applications. The propagation velocity of hydrogen flames is high enough to cause severe explosion over an extensive range of 4%–75% H<SUB>2</SUB>. Therefore, the use of hydrogen carries a great risk, and the requirement for its leakage detection is imperative in hydrogen generation, transportation, stockpiling, and its utilization. Usage of MOX and FETs has increased tremendously in designing precise hydrogen sensors. Therefore, in this review, the authors have focused on the recent development in MOX and FET based hydrogen sensors. MOX sensors are most widely available as commercialized ones.Also, FET-type gas sensors have many advantages, compared with traditional ones owing to their reduced shape, size, and lower production cost. Nevertheless, the processing parameters and reproducibility need to be enhanced for expanding their applications. In this review, the role of the important sensing parameters, e.g., measurement range, sensitivity, selectivity, response and recovery time, on the sensing mechanism and operation, and the most recent innovation and improvement in MOX and FET sensing technologies are discussed. Finally, we report the sensing techniques, mechanism and factors affecting the sensitivity for MOX and MOSFET type sensors.</P>
Sharma, Amit Kumar,Bhushan, Bharat,Kumar, Sanjeev,Kumar, Pushpendra,Sharma, Arjava,Kumar, Satish Asian Australasian Association of Animal Productio 2004 Animal Bioscience Vol.17 No.9
Random amplification of polymorphic DNA-Polymerase Chain Reaction (RAPD-PCR) analysis was carried out using DNA samples of 30 animals of Rathi cattle and 42 animals of Tharparkar cattle. Genomic DNA was isolated as per standard protocol and evaluated for its quality, purity and concentration. Twenty three random primers were screened out of which 15 primers yielded satisfactory amplifications and were used for further analysis. Average numbers of polymorphic fragments per primer were 7.07${\pm}$0.86 in Rathi and 6.80${\pm}$0.61 in Tharparkar cattle. The percentage of polymorphic bands in these two cattle breeds were 86 and 87%, respectively. Within breed genetic similarities for pooled over primers in the animals of Rathi and Tharparkar breeds were .577${\pm}$0.30 and 0.531${\pm}$0.02, respectively on the basis of band frequency (BF) and 0.645${\pm}$0.04 and 0.534${\pm}$0.04, respectively on the basis of band sharing (BS). Averages of between breed genetic similarities for pooled over primers were 0.97 and 0.92 according to BF and BS, respectively, which reflect higher degree of genetic similarity between Rathi and Tharparkar cattle breeds. Index of genetic distance based on BF and BS for pooled over primers was 0.030${\pm}$0.011 and 0.088${\pm}$0.031, respectively. Percentage of polymorphic bands and within-breed genetic similarities on the basis of band frequency (BF) and band sharing (BS) for pooled over primers revealed higher genetic similarity in Rathi than Tharparkar cattle population. High estimates of between breed genetic similarities for pooled over primers indicated that either Rathi is having decent from Tharparkar or both the cattle breeds are having common descent. Low value of Index of genetic distances between these two cattle breeds may be due to the fact that Rathi and Tharparkar cattle breeds are the native of Thar Desert in Northwest India. The results of between breed genetic distances also confirm the existence of high degree of genetic similarity between these two breeds of cattle.
Enhancing mechanical and durability properties of geopolymer concrete with mineral admixture
Bharat Bhushan Jindal,Dhirendra Singhal,Sanjay Sharma,Parveen 사단법인 한국계산역학회 2018 Computers and Concrete, An International Journal Vol.21 No.3
This paper approaches to improve the mechanical and durability properties of low calcium fly ash geopolymer concrete with the addition of Alccofine as a mineral admixture. The mechanical and durability performance of GPC was assessed by means of compressive strength, flexural strength, permeability, water absorption and permeable voids tests. The correlation between compressive strength and flexural strength, depth of water penetration and percentage permeable voids are also reported. Test results show that addition of Alccofine significantly improves the mechanical as well as permeation properties of low calcium fly ash geopolymer concrete. Very good correlations were noted between the depth of water penetration and compressive strength, percentage permeable voids and compressive strength as well as between compressive strength and flexural strength.
Strength and permeation properties of alccofine activated low calcium fly ash geopolymer concrete
Bharat Bhushan Jindal,Dhirendra Singhal,Sanjay Sharma,Aniket Yadav,Shubham Shekhar,Abhishek Anand 사단법인 한국계산역학회 2017 Computers and Concrete, An International Journal Vol.20 No.6
This paper presents the experimental investigations on the compressive strength and permeation properties of geopolymer concrete prepared with low calcium fly ash as the primary binder activated with different percentage of Alccofine. The durability aspect was investigated by performing permeable voids and water absorption tests since permeability directly influences the durability properties. The test results show that Alccofine significantly improves the compressive strength and reduces the water permeability thus enhances the durability of geopolymer concrete at ambient curing regime which encourages the use of geopolymer concrete at ambient curing condition thus promising its use in general construction also.
Pulmonary Artery Stenosis due to Lung Carcinoma: A Rare Cause of Dyspnea
Rajiv Bharat Kharwar,Akhil Sharma,Rishi Sethi,Varun Shankar Narain,Ram Kirti Saran 한국심초음파학회 2014 Journal of Cardiovascular Imaging (J Cardiovasc Im Vol.22 No.4
Acquired bilateral pulmonary artery stenosis in adults due to lung malignancy is infrequently reported. We describe an adultmale who presented to us with chief complaints of dyspnea on exertion and one episode of hemoptysis. Two dimensionaltransthoracic echocardiography with color Doppler showed presence of an extra cardiac mass causing severe extrinsic compressionof both the right and left pulmonary artery leading to high pressure severe tricuspid regurgitation and extension of the mass intothe left atrium. Three dimensional transthoracic echocardiography clearly delineated the anatomy of the left atrial mass and itssurrounding anatomical relationship. The diagnosis of non small cell lung carcinoma was confirmed by multidetector computedtomography (MDCT) and with MDCT guided biopsy with histopathology. Patient succumbed one month later due to anepisode of massive hemoptysis.