A brief study on various time domain viscoelasticity model

A viscoelastic material stores energy and dissipates it in the thermal domain when subjected to dynamic loading and most interestingly the storage and loss of energy depend upon the frequency of excitation. To find a time domain model to represent the behaviour viscoelastic solids found interest of many researchers. Bagley and Torvik (1983, 1985) represented frequency dependent behaviour of viscoelastic solids by using four-model parameters and differential operators of fractional order. The time-domain model with ordinary integer differential operators was developed by Golla and Hughes (1985), who incorporated the hereditary integral form of the viscoelastic constitutive law in a finite element model. The finite-element equations are derived in the Laplace domain through the Ritz technique. McTavish and Hughes (1992, 1993) extended the Golla-Hughes model and formulated the GHM (Golla-Hughes-McTavish) model for linear viscoelastic structure

Pattern of Agricultural Diversification in India

Agricultural diversification as measured by increase in the percent of non-food crops has grown; whereas diversification as measured by the concentration indices has remained unchanged in the recent decade. There have been significant changes in the pattern of agricultural diversification at the regional level. Within a region, smaller sub-regions or pockets of specialization in certain crops and crop-groups have emerged. Farms do not remain diversified and the usual notion of crop diversification as a risk management practice is also belied in the present study. The study also found certain kind of structural changes in all sub-sectors of agriculture : crop, livestock, and fisheries. Concerns over extreme effects of such changes are however, not valid.agricultural diversification, Agriculture Analysis, India, non-food crops, crop, livestock, and fisheries

Preparation of Ceramic Porous Body Using Different Volume Concentration of Ball Clay & Wheat Flour

The rheological study of the slurry containing ball clay and using different deflocculant (Sodium Silicate) concentration has been done. Slurry with different solid loading are prepared by taking ball clay and water in different proportions with solid loading 30%, 35% and 40% (by volume). Deflocculant with different concentrations are mixed with different slurries (with different solid loading). Deflocuculant with 5 different proportions was taken. Defloculant with 0.25%, 0.5%, 0.75%, 1 % and 1.25% (weight %) of the clay were taken and poured in a plastic bottle with alumina balls for wet milling for 12hrs. Rheology of the slurry was then studied by measuring the viscosity, sedimentation height and zeta potential of the slurry. Further with this optimized solid loading (30 Vol% Solid Loading) and the amount of deflocculant (0.85 wt. % of Ball clay), ceramic porous body was prepared with this fixed solid loading, but varying the ratio of ball clay and wheat flour. In this fixed solid loading, the wheat flour and ball clay was varied in the ratio 10:90, 20:80, 30:70, 40:60 and 50:50 by volume.The different slurry was prepared with varying ratio of wheat flour and ball clay as mentioned above. In this slurry, the amount of deflocculant was fixed 0.85% (wt %) of the total ball clay taken. These slurries were mixed through pot milling for 12 hours. Then the slurry was casted in a metal mold and kept at drier for 24 hours to get a cylindrical shaped body which was later fired at a different temperature. Different samples were fired at different temperatures to get the final ceramic porous body. Samples were fried at 11000C, 12000C and 13000C. Then characterization of the prepared ceramic porous body was done by determining Drying Shrinkage, Firing shrinkage, Apparent Porosity, Bulk Density and Cold Crushing strengt

Analysis of the results of surgical management of traumatic paraplegia

Background: Thoracolumbar spine fractures are common injuries that can result in significant disability, deformity and neurological deficit. Aim of this study was to evaluate the results of surgical management of traumatic paraplegia, complete or incomplete as classified by Frankel scoring.Methods: A prospective study was conducted in patients attending outdoor and emergency department of orthopaedics of a tertiary care teaching institute in Katihar Medical College, Katihar (Bihar) with traumatic paraplegia involving the dorsolumbar spine. The duration of the study was July 2014 to July 2016. The important objectives are the time for recovery of various functions like sensory, motor and bowel and bladder function, comparison between early and late decompression, results of posterolateral fusion and time taken for solid bony fusion after operation. Cases selected for these studies were those treated surgically between July 2014 to July 2016. Total 46 cases were selected within a minimum of 6 month post-operative follow up of which 4 cases lost in follow up. Data collected from patients records including age, sex, time from injury to hospitalization, initial neurological status as per Frankel score, MRI findings, surgery performed, postoperative course and neurological status at the time of discharge and latest follow up. Patients lost to follow up were not studied for outcome analysis.Results: When decompression done within 1st week in incomplete paraplegia 80% of the patients showed return of grade 3 power. In complete paraplegia cases, 11% of the patients had return to power upto grade 3 when decompression done within 1 week where no cases return of grade 3 power when decompression done after2nd and 3rd week. Conclusions: After recovery from spinal shock, the earlier the surgical decompression done, the better the neurological and bowel/bladder function recovery both in complete and incomplete paraplegic cases. Reduction is better and easy and less time consuming in early decompression than in late. Motor recovery can continue for over 6 month after decompression.

Planar Hall effect in the Weyl semimetal GdPtBi

Observation of Weyl and Dirac Fermions in condensed matter systems is one of the most important discoveries. Among the very few available tools to characterize Weyl semimetals through electrical transport, negative magnetoresistance is most commonly used. Considering shortcomings of this method, new tools to characterize chiral anomaly in Weyl semimetals are desirable. We employ planar Hall effect as an effective technique in half Heusler Weyl semimetal GdPtBi to study chiral anomaly. This compound exhibits a large value of 1.5 mohm cm planar Hall resistivity at 2 K and in 9 T. Our analysis reveals that the observed amplitude is dominated by Berry curvature and chiral anomaly contributions. Through the angle dependent transport studies we establish that GdPtBi with relatively small orbital magnetoresistance is an ideal candidate to observe large planar Hall effect .Comment: Updated text

Exhaled nitric oxide atopy, and spirometry in asthma and rhinitis patients in India

  INTRODUCTION: Asthma is a chronic airway inflammatory disorder. Nitric oxide (NO) is non-invasively measured in exhaled breath (FeNO). The aim of the study was to investigate the anthropometric and physiologic factors that influence FeNO measurements. Also, to evaluate FeNO correlation with spirometry and inflammatory markers in asthma and rhinitis. MATERIAL AND METHODS: The study was a prospective analysis of asthma (BA) and rhinitis (AR) in patients enrolled from outpatient clinics between 2011 and 2015. Healthy controls (HC) were enrolled from the community. All subjects underwent baseline spirometry with reversibility, FeNO measurements, skin prick tests, and blood sampling for absolute eosinophil counts and serum total IgE levels. RESULTS: Of 528 enrolled participants, 215 were BA, 248 were BA-AR and 65 were HC. The mean FeNO was higher in atopic versus nonatopic subjects (34.14 vs. 25.99; p < 0.001); asthmatics versus non-asthmatics (30.46 vs. 12.91; p < 0.001), and in participants with BA-AR, compared to those without BA-AR (32.56 vs. 30.46; p < 0.001). The odds ratio for FeNO in the study population showed a significant positive association with male gender, absolute eosinophil count (AEC), breathlessness, duration of symptoms, family history and atopy. In examining the diagnostic accuracy of FeNO for asthma, the AUC for FeNO value is 0.833 (95% confidence interval [CI], 0.717–0.901), with cut-off levels to screen for asthma being 19.45 at 71.2% sensitivity and 81.8% specificity (p < 0.001). The Positive Predictive Value 96.84% (95% CI: 94.43–98.23) and Negative Predictive Value 30% (95% CI: 23.78–37.05) for asthma prediction with FeNO. CONCLUSION: The study highlights the importance of estimation of anthropometric parameters and dyspnea assessment in the evaluation of FeNO levels. Also, the presence of atopy may influence the results in the interpretation of FeNO readings. Moreover, the study have demonstrated that spirometry and FeNO have no significant correlation, which further lays emphasis on them as being different physiological parameters of asthma.