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Pushpendra Kumar Dwivedi,R. Vinjamuri,S. K. Sahoo,Krishna Dutta 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.8
Ratcheting deformation in association with bulk texture evolution in HSLA steel is studied in this investigation. The cyclicdeformation behaviors and damage modes of the specimens are obtained at room temperature, employing asymmetric stresscontrolledtests under various combinations of mean stress and stress amplitudes. Bulk texture measurements of the specimensare done adopting an X-ray diffraction analysis. The results exhibit an increase in strain accumulation from 0.23 to 30.61%associated with a sharp reduction in ratcheting life from 3320 to 880 cycles by the increment in mean stress/stress amplitude. A continuous cyclic softening until the final failure is observed for all the ratcheting tests. It is noticed that variation of meanstress is more detrimental than stress amplitude in controlling strain accumulation while the effect of stress amplitude is morepronounced than mean stress for the reduction of ratcheting life. The fracture surface morphology indicates typical striationformation in the crack propagation region along with overload failure. The bulk texture studies indicate that there is a transitionbetween ‘ϒ’ fiber and ‘ζ’ fiber during all loading conditions. The texture intensity is increased from 5.71 to 11.68 withprogressive ratcheting strain accumulation. Here also, influence of stress amplitude is more significant than the mean stress.
Pawan Kumar,Rakesh Kumar Dwivedi,Pawan Kumar,Ravikant Prasad,Praveen Kumar Siwach,Hari Krishna Singh 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.58 No.1
Thin films of La_(0.80)Sr_(0.20)Mn_(1−x)Cu_xO_3 with x = 0.00, 0.04, 0.08, 0.10, 0.15, and 0.20 were deposited on single-crystal LaAlO_3 (100) (LAO) substrates at 250 ± 10 ℃ by using a nebulized spray pyrolysis technique. Structural, surface, and transport characterizations were done by X-ray diffraction (XRD), atomic force microscopy (AFM) and the standard four probe technique, respectively. XRD patterns revealed the formation of single-phase polycrystalline films with a rhombohedral crystal structure. Cu substitution resulted in a uniform decrease in the metal insulator transition (T_(IM)) temperature up to x = 0.10, followed by a drastic decrease in T_(IM) for x = 0.15. Finally, the metal-insulator transition vanished for higher Cu concentrations (x = 0.20) in the observed temperature range. The variation in T_(IM) with the amount of added Cu is explained on the basis of the double exchange mechanism. Cu substitution has been found to perturb the Mn^(3+)-O-Mn^(4+) network and has a strong influence on T_(IM). The variation in resistivity maxima with temperature for different Cu concentrations showed a systematic trend up to x ∼ 0.10. We also explored the electrical conduction at T > T_(IM) in the framework of small polaron hopping in the adiabatic limit. The activation energy showed a strong dependence on the Cu concentration. The maximum magneto-resistance (MR) up to 10%, was observed for x = 0.15 at low temperatures.
( Kumar Krishna Agrawaal ),( Prahald Karki ),( Nikesh Shrestha ),( Madhab Lamsal ) 대한내과학회 2014 대한내과학회 추계학술대회 Vol.2014 No.1
Background: Cardiac biomarkers provide a convenient and noninvasive means to gain insights into the underlying causes and consequences of ACS that mediate the risk of recurrent events and may be targets for specifi c treatment. The role of high sensitivity C reactive protein (hsCRP) for predicting the outcome has been established.There are studies to show the prognostic importance of estimated glomerular fi ltration rate. But our population differs genetically and environmentally as compared to west. Methods: It was a Prospective observational study. The Primary Outcome was taken as all cause mortality.Consecutive patients with the diagnosis of acute coronary syndrome giving consent for the study were enrolled and followed up at 6 weeks and 6 months. Mortality and the likely cause of death were recorded along with the day since admission. HS CRP was estimated on admission, at 6 weeks and at 6 months. The eGFR was calculated using the abbreviated MDRD formula at admission, at 6 weeks and 6 months. Results: There were 108 cases of ACS in duration of 6 months.The study showed 44% of patients had STEMI; 41% had NSTEMI and 23% had UA. The HS-CRP level of > 5mg/dl was highly signifi cant for predicting mortality during hospital stay and at 6 weeks (p-<0.001). There was 11% of in hospital mortality (p<0.001). At 6 months the overall mortality was 28% (p-<0.001). Arrhythmias were observed in 27% patients (p<0.001). Cardiogenic shock complicating STEMI resulted in high patient mortality (p-0.001). There was a statistical signifi cance with low eGFR (median eGFR 45 ml/ min/1.73 m2) levels during the admission. Illiteracy, Smoking and diabetes mellitus of duration more than 10 years was associated with increased risk of mortality. Conclusions: HS CRP> 5mg/dl, the eGFR levels =30ml/min/1.73 m2, Age >75 years, albuminuria and cardiogenic shock were signifi cant in predicting mortality in patients of ACS.
Arsenic Exposure and Haematological Derangement in Cervical Cancer Cases in India
Kumar, Rahul,Trivedi, Vinita,Murti, Krishna,Dey, Akalanka,Singh, Jitendra Kumar,Nath, A,Das, P Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.15
Cervical cancer is the second most common gynecological malignancy worldwide. According to HPV Information Centre, Spain (Aug'2014), in India approximately 1,22,844 women are diagnosed with the disease every year and of them 67,477 die due to the disease. CaCx is said to be mediated by HPV but recent data published reveal the role of Oxidative Stress in different Cancers. Arsenic is also one of the agents for causing Oxidative Stress. Arsenic has been linked with different types of cancer. Arsenic is considered responsible for generation of free radicals and eventually for apoptosis. Early diagnosis of CaCx is presently a matter of concern and clinical presentation in advanced stages become difficult for complete clinical response. For determination of oxidative stress, Malondialdehyde (MDA) was taken as an identifier and arsenic estimation was performed with the help of Atomic Absorption Spectrometer (AAS). RBC count and Haemoglobin levels were performed according to standard protocol. MDA was in direct proportion with arsenic concentration and inversely proportional to RBC and Haemoglobin in CaCx patients. Arsenic is one of the major causative agents for oxidative stress and hence may be a risk factor leading to cancer including CaCx.
Krishna Kumar Chandra 강원대학교 산림과학연구소 2018 Journal of Forest Science Vol.34 No.5
Agroforestry is emerged as climate smart agriculture system and known to help in maintaining soil nutrient sustainability but its rate of expansion is still not appreciable. The present paper incorporates the different species under various agroforestry practices its density, growth and growing stock. The most dominated agroforestry practices in Bilaspur district identified as boundary tree based agri- silviculture (32%) followed with inside field tree based agri-silviculture (21%). Agri-horti-silvicultural system found merely in 5% farmer’s field while silvo-pastoral practice in 8% fields. The result depicts that the most prevailing agroforestry tree species in non-forest area of Bilaspur comprises Acacia nilotica 36%, Butea monosperma 22%, Albizia spp 16%, Terminalia arjuna 7%, Azadirachta indica 3.5% and other species 15.5%. More than 90% farmer allows tree species growing naturally in their fields mainly for fuel wood, timber and as source of additional income as these species need not require special attention and care, while only 5% farmer’s has adopted Tectona grandis, Dalbergia sissoo etc commercially for higher future return. The paper also discusses the constraints on agroforestry for enabling development of agroforestry in future.
Effect of fiber and aggregate size on mode-I fracture parameters of high strength concrete
Kumar, Ch.Naga Satish,Krishna, P.V.V.S.S.R.,Kumar, D.Rohini Techno-Press 2017 Advances in concrete construction Vol.5 No.6
In this paper, an experimental investigation was carried out to study the effect of volume fraction of fiber and maximum aggregate size on mode-I fracture parameters of high strength concrete. Total of 108 beams were tested on loading frame with three point loading, the variables in the high strength concrete beams are aggregate size (20 mm, 16 mm and 10 mm) and volume fraction of fibers (0%, 0.5%, 1% and 1.5%). The fracture parameters like fracture energy, brittleness number and fracture process zone were analyzed by the size effect method (SEM). It was found that fracture energy (Gf) increases with increasing the Maximum aggregate size and also increasing the volume of fibers, brittleness number (${\beta}$) decreases and fracture process zone (CF) increases.
Krishna Kumar Jaiswal,Ishita Banerjee,Swapnamoy Dutta,Ravikant Verma,Lokanadhan Gunti,Sharad Awasthi,Mayank Bhushan,Vinod Kumar,Mohamed Fahad Alajmi,Afzal Hussain 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.107 No.-
The rapid emergence of multidrug-resistant microbes has turned into the main threat to public healthworldwide. The preparation and application of nanomaterial-based antimicrobials have increased toaddress this problem with great significance. This study has investigated the bio-fabrication of polycrystallineAg-NCs using BCE as a reducer and stabilizer under microwave irradiation. Ag-NCs formationswere optimized using varying concentrations of BCE and silver acetate. The XRD confirmed the incidenceof phases of nanostructured crystals of Ag/AgO/AgCl. The average crystallite sizes were calculated to be22.19, 36.65, and 36.65 nm for Ag, AgO, and AgCl, respectively. SERS spectra revealed the vibrationalmodes of the Ag and Ag-O stretch bands. FTIR spectra have indicated the incidence of chemical fingerprintsfor Ag-NCs and BCE biomolecules. SEM and HR-TEM micrographs exhibited the almost sphericalto the oval shape of 50 nm. SAED pattern attested to silver crystallinity in agreement with XRD analysis. The MIC values of the Ag-NCs against Escherichia coli, Staphylococcus aureus, Aspergillus brasiliensis, andRhizopus stolonifer were observed to be 120, 60, 200, and 100 mg/ml, respectively. This study has demonstratedthe facile method to prepare polycrystalline Ag-NCs with appropriate structural and morphologicalcharacteristics for antimicrobial applications.
SEMI-MARKOV COMPARTMENTAL MODELS OF INVADING INSECT POPULATIONS
Kumar, Krishna B.,Arivudainambi, D. 한국전산응용수학회 2000 Journal of applied mathematics & informatics Vol.7 No.1
The total number of deaths and total sojourn times of African honey bees are studied using semi-markov compartment analysis. This generalizes many existing biological models.
Krishna Kumar Govindarajan 대한소아청소년과학회 2018 Clinical and Experimental Pediatrics (CEP) Vol.61 No.6
Perforation of the esophagus is an uncommon problem with significant morbidity and mortality. In children undergoing endoscopy, the risk of perforation is higher when interventional endoscopy is performed. The clinical features depend upon the site of esophageal perforation. Opinions vary regarding the optimal treatment protocol, and the role of conservative management in this context is not well established. Esophageal perforation that occurs as a consequence of endoscopy in children requires careful evaluation and management, as outlined in this article.