1,141 research outputs found
The nature and boundary of the floating phase in a dissipative Josephson junction array
We study the nature of correlations within, and the transition into, the
floating phase of dissipative Josephson junction arrays. Order parameter
correlations in this phase are long-ranged in time, but only short-ranged in
space. A perturbative RG analysis shows that, in {\it arbitrary} spatial
dimension, the transition is controlled by a continuous locus of critical fixed
points determined entirely by the \textit{local} topology of the lattice. This
may be the most natural example of a line of critical points existing in
arbitrary dimensions.Comment: Parts rewritten, typos correcte
Reduction of hand transmitted and whole body vibrations experienced by tractor operators by using piezo crystal material
A study was proposed to investigate the effects of vibration on tractor operator’s health attempting a biodynamic and physiological approach. The source vibration levels at steering wheel and seat for the hand transmitted and whole body vibration during different tractor operations were measured. Two isolators, one commercially available, made of styrene butadiene rubber (SBR) and the other custom designed, made of piezo-electric material embedded in SBR were tested for attenuation of vibration. It was observed that an average 40% reduction in vibration intensity was experienced with installation of custom-designed isolator underneath the tractor operator’s seat. The measured values of vertical vibration at operator’s seat were found to be within 8 h fatigue decreased proficiency boundary limit. Incorporation of custom-designed isolator reduced the muscle load to a maximum of 44.37% in erector spinae muscle during first tilling operation, while flexor carpi radialis in transport attained 23.03% reduction. Keywords: Piezo crystal, vibration, transmissibility, accelerometer, isolators
Translational vibration evaluation of tractor seats for ride comfort
An investigation was carried out on tractor seat design for better operator comfort during operation. The project objectives were mainly aimed to increase the ride comfort by improving the seat suspension which is used in Indian tractors. Tests were conducted for haulage operation and also for field operation. During haulage operation tests were carried out onexisting seats used in Indian tractors with three new selected suspension systems of the two most selling models of MF 241 and MF 1035. The model MF 241 equipped with a existing seat is mostly used in India, while the model MF 1035 consists of exported benchmark seat (for comparison) which is a seat whose suspension appeared to majority of operators is used for more comfortable and rest three selected seat suspensions were replaced to same existing seat used in India. Tests were conducted with three different operators representing 5th, 50th and 95th percentile (SM1, SM2 and SM3) of the population of India. Best suspension system was selected, based on weighted RMS acceleration awx, awy, awz for each axis and the acceleration vector sum av performance. The values of weighted RMS acceleration awx, awy, awz, and acceleration vector sum av of different suspension systems were compared with exported benchmark seat as well as existing seat mostly used in India. The changes in the vibration peak along with speed were compared graphically. It was observed that the SP2 suspension gives better result amongthree selected suspensions. The results were comparable with exported benchmark seat in higher speed range which was available in developed countries.Keywords: seat suspension, weighted R.M.S acceleration, spring constan
Estimation of plant nitrogen content using digital image processing
A manually operated four wheel test trolley was designed and developed for acquiring outdoor color images of plant under controlled illumination to predict crop nitrogen content in field. This set up consists of a camera to capture the plant image, four lights to control illumination and a laptop for processing the signal. The developed unit was evaluated rigorously for paddy crop for four observations at fifteen days interval after transplantation. The results were compared with the chlorophyll content of the crop measured by SPAD meter and the chemical analysis of plant leaf. The processing of the color plant image was done in MATLAB 7.0 program. Various features such as R, G, B, normalized ‘r’ and normalized ‘g’ were analyzed for both the processes. Regression models were developed and evaluated between various image feature and the plant nitrogen content and observed that, the minimum accuracy was found to be 65% with an average accuracy of 75% (Standard Deviation +1.9), actual and predicted values of nitrogen percent were linearly correlated with R2 value (0.948), this showed that the plant nitrogen content can be successfully estimated by its color image feature. Keywords: precision agriculture, digital image processing, site specific nitrogen applicatio
Orientation-dependent solid solution strengthening in zirconium: a nanoindentation study
Orientation-dependent solid solution strengthening was explored through a combined microtexture plus nanoindentation study. Pure zirconium (6N purity crystal-bar Zr) and commercial Zircaloy-2 were investigated for comparison. Local mechanical properties were estimated through finite element (FE) simulations of the unloading part of the nanoindentation load–displacement response. Combinations of ‘averaging’ scheme and constitutive relationship were used to resolve uncertainty of FE-extracted mechanical properties. Comparing the two grades, non-basal oriented grains showed an overall hardening and increase in elastic modulus. In contrast, insignificant change was observed for basal (or near-basal) oriented grains. The strengthening of non-basal orientations appeared via elimination of the lowest hardness/stiffness values without a shift in the peak value. Such asymmetric development brought out the clear picture of orientation-dependent solid solution strengthening in zirconium
Failure Investigation of a Boiler Pipe
The damaged boiler pipe from the cochran horizontal pipe
type boiler was investigated to study the cause of its failure. The damaged pipe having a through hole of about 4mm size was studied from both water and fire side with the help of visual inspection, physical measurements, optical micrograph, x-ray diffraction (XRD) and Electron probe microanalysis (EPMA).It was concluded that water side corrosion was more predominant than the fire side corrosion in reducing the thickness of the plate and eventually causing a through hole. The higher rate of
corrosion from water side may he attributed mainly due to the presence of large amount of inclusions which led to preferential dissolution of matrix around them. The water side corrosion product was non adherent, fragile and powdery whereas fire side corrosion product was adherent
Exploitation of mica deposits at Nellore mica belt, Andhra Pradesh, India
India is the leading producer of sheet mica and a
major part of this is exported. Nellore mica belt is the
largest mica-producing area covering part of Nellore
district in Andhra Pradesh, India. As most of the
mines are old and privately operated, they are developed
and operated purely based on local experiences.
In this article, we highlight the problems associated
with the present mica-mining practices in the Nellore
mica belt, and scientific approaches that have been
adopted for fixing different parameters associated
with mica extraction. Based on detailed field study,
geo-mechanical data and tested rock properties,
extensive numerical modelling is done to suggest the
best possible method of mining for safe and sustainable
mica extraction from the area
Evaluation of the Immunoprotective Potential of Recombinant Paraflagellar Rod Proteins of Trypanosoma evansi in Mice
Trypanosomosis, caused by Trypanosoma evansi, is an economically significant disease of livestock. Systematic antigenic variation by the parasite has undermined prospects for the development of a protective vaccine that targets the immunodominant surface antigens, encouraging exploration of alternatives. The paraflagellar rod (PFR), constituent proteins of the flagellum, are prominent non-variable vaccine candidates for T. evansi owing to their strategic location. Two major PFR constituent proteins, PFR1 (1770bp) and PFR2 (1800bp), were expressed using Escherichia coli. Swiss albino mice were immunized with the purified recombinant TePFR1 (89KDa) and TePFR2 (88KDa) proteins, as well as with the mix of the combined proteins at equimolar concentrations, and subsequently challenged with virulent T. evansi. The PFR-specific humoral response was assessed by ELISA. Cytometric bead-based assay was used to measure the cytokine response and flow cytometry for quantification of the cytokines. The recombinant TePFR proteins induced specific humoral responses in mice, including IgG1 followed by IgG2a and IgG2b. A balanced cytokine response induced by rTePFR 1 and 2 protein vaccination associated with extended survival and improved control of parasitemia following lethal challenge. The observation confirms the immunoprophylactic potential of the covert antigens of T. evansi
Associations between environmental factors and hospital admissions for sickle cell disease
Sickle cell disease (SCD) is an increasing global health burden. This inherited disease is characterised by a remarkable phenotypic heterogeneity, which can only partly be explained by genetic factors. Environmental factors are likely to play an important role but studies of their impact on disease severity are limited and their results are often inconsistent. This study investigated associations between a range of environmental factors and hospital admissions of young patients with SCD in London and in Paris between 2008 and 2012. Specific analyses were conducted for sub-groups of patients with different genotypes and for the main reasons of admissions. Generalized additive models and distributed lag non-linear models were used to assess the magnitude of the associations and to calculate relative risks. Some environmental factors significantly influence the numbers of hospital admissions of children with SCD, although the associations identified are complicated. Our study suggests that meteorological factors are more likely to be associated with hospital admissions for SCD than air pollutants. It confirms previous reports of risks associated with wind speed (RR: 1.06/SD [95% confidence interval (CI): 1.00-1.12]) and also with rainfall (RR: 1.06/SD [95%CI: 1.01-1.12]). Maximum atmospheric pressure was found to be a protective factor (RR: 0.93/SD [95%CI: 0.88-0.99]). Weak or no associations were found with temperature. Divergent associations were identified for different genotypes or reasons of admissions, which could partly explain the lack of consistency in earlier studies. Advice to patients with SCD usually includes avoiding a range of environmental conditions that are believed to trigger acute complications, including extreme temperatures and high altitudes. Scientific evidence to support such advice is limited and sometimes confusing. This study shows that environmental factors do explain some of the variations in rates of admission to hospital with acute symptoms in SCD, but the associations are complex, and likely to be specific to different environments and the individual's exposure to them. Furthermore, this study highlights the need for prospective studies with large numbers of patients and standardised protocols across Europe
Prevalence of porcine cysticercosis in Bareilly, Northern India
Aim: The objective of this study was to investigate the prevalence of Taenia solium cysticercosis in pigs slaughtered at makeshift houses in Bareilly, Northern India.
Materials and Methods: Local makeshift slaughter houses were visited weekly in Bareilly to explore the prevalence of the porcine cysticercosis in this area. 175 pigs were screened for cysticercosis and prevalence was correlated to age, sex and breed of pigs.
Results: A total of 175 pigs were examined for cysticercosis out of which 9 (5.14%) were found positive for porcine cysticercosis. Sex-wise prevalence of this infection in male and female was recorded as 4.82% (4/83) and 5.43% (5/92), respectively. The infection was higher (5.34%) in the young age group of 1-12 months as compared to the older stocks of 13-24 months of age group (4.54%). Prevalence of porcine cysticercosis was relatively higher in cross bred pigs (5.88%, 6/102) than in the non-descript local breed of pigs (4.11%, 3/73).
Conclusion: The present study reveals that T. solium cysticerci infection is prevalent in swine population of Bareilly. Keeping in view the zoonotic importance, strict hygienic measures need to be undertaken for prevention of human infection
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