178 research outputs found
Chasing the Shadows: A study of The Half Mother
The three decade old armed conflict in Kashmir has claimed thousands of lives, left hundreds homeless and rendered numerous youth missing. The vacillation of the Kashmir issue has raised a furore and frenzy among the people and it has been registered and documented in various literary and non-literary genres. The narratives about the state of conflict and its impact on the populace are tendentious, written from extrinsic and probative positions that fall in the ambit of mainstream narratives. Lately, the indigenous writers from Kashmir have registered the grim accounts of the impact of insurgency and militancy in the state and the unabated military action. The native writers have a firsthand account of the events of the turmoil. One such writer Shahnaz Bashir’s The Half Mother is a doleful story of Haleema, the protagonist who is an epitome of valiance and courage. It is a woeful tale of a grief stricken mother who loses her only son to the enforced disappearance at the hands of the armed forces In this paper, I aim to highlight the importance of the native Kashmiri writers in bringing out the honest and truthful accounts of the impact of militancy on the contemporary Kashmiri literature
Modeling and prediction of wear rate of aluminum alloy (Al 7075) using power law and ANN
The wear process significantly influences machine parts during their useful life. The wear process is complex, and therefore, it is very difficult to develop a comprehensive model involving all the operating parameters. In the present study, wear rate is measured during the wear process at different operating parameters such as force (load), sliding distance, and velocity. Power law and Artificial neural network (ANN) approaches are used to model the wear rate of Al7075 alloy. Power law and neural network-based models are compared using statistical methods with a coefficient of determination (R2), mean absolute percentage error (MAPE), and means square error (MSE). It is seen that the proposed models are competent to predict the wear rate of Al7075 alloy. The ANN model estimates the wear rate with high accuracy compared to that of the power law model. The models developed for wear rate were found to be consistent with the experimental data. ANOVA analysis revealed that the load has a significant effect on the wear rate than the sliding speed and sliding distance
Tribological properties of IF-MoS<inf>2</inf> nanoparticles as lubricant additive on cylinder liner and piston ring tribo-pair
Friction and wear behaviors of different concentrations of IF-MoS2 nanoparticles in SAE 20W40 were studied. First of all tribological tests with SAE 20W40 + IF-MoS2 were carried out on a four ball wear test machine as per ASTM D 4172 standard to study its wear properties. Detailed friction and wear studies on cylinder liner and piston ring tribo-pair were conducted on pin-on-block universal tribometer under lubricated conditions of SAE 20W40+ IF-MoS2. These experimental studies were conducted at different operating parameters to ascertain the influence of nanoadditive on friction and wear of cylinder liner and piston ring tribo-pair. A minimum coefficient of friction of 0.0772 was observed for 0.5 wt% of IF-MoS2 at normal load of 100 N at sliding velocity of 0.03 m/sec. A substantial reduction of 65% in the wear of cylinder liner and piston ring tribo-pair was also observed when lubricated with SAE 20W40 and 0.5 wt% of IF-MoS2. Scanning electron microscopy and energy dispersive spectrometry analysis of the worn out surfaces was also carried out to find the causes for observed friction and wear behavior
Friction and wear reduction by graphene nano platelets for hybrid nano Aluminium matrix composite under dry sliding conditions
Friction losses and wear losses are the main failure reasons in the internal combustion (IC) engine components i.e., cylinder liner and piston. So, it demands lightweight self-lubricating low friction and wear-resistant materials to increase the efficiency and reduce the emission issue of the IC engine. In this concern, tribological tests are performed on self-lubricating aluminium composites samples reinforced with 6 wt.% of γ-Al2O3 and Graphene Nano Platelets (GNP) with varying concentration (0.5 wt.% - 5 wt.%), using ball-on-disc tribo-configuration under dry sliding conditions. The scope of this study is to investigate the anti-friction and anti-wear properties of GNP as reinforcement in the hybrid nanocomposite. The hybrid nanocomposite samples are fabricated using Spark Plasma Sintering (SPS) fabrication route. From the results, it is reported that friction and wear reduction percentage is 37.43 % and 51.64 %, respectively for the hybrid nanocomposite with 5 wt. % GNP. It is attributed to the inclusion of GNP, which reduces the Coefficient of Friction (COF) and improves wear resistance of the composite significantly
Modeling and optimization of flank wear and surface roughness of Monel-400 during hot turning using artificial intelligence techniques
This work aims to model and investigate the effect of cutting speed, feed rate, depth of cut and the workpiece temperature on surface roughness and flank wear (responses) of Monel-400 during turning operation. It also aims to optimize the machining parameters of the above operation. A power-law model is developed for this purpose and is corroborated by comparing the results with the artificial neural network (ANN) model. Based on the coefficient of determination (R2), mean square error (MSE), and mean absolute percentage error (MAPE) the results of the power-law model are found to be in close agreement with that of ANN. Also, the proposed power law and ANN models for surface roughness and flank wear are in close agreement with the experiment results. For the power-law model R2, MSE, and MAPE were found to be 99.83%, 9.9×10-4, and 3.32×10-2, and that of ANN were found to be 99.91%, 5.4×10-4, and 5.96×10-2, respectively for surface roughness and flank wear. An error of 0.0642% (minimum) and 8.7346% (maximum) for surface roughness and 0.0261% (minimum) and 4.6073% (maximum) for flank wear were recorded between the observed and experimental results, respectively. In order to optimize the objective functions obtained from power-law models of the surface roughness and flank wear, GA (genetic algorithm) was used to determine the optimal values of the operating parameters and objective functions thereof. The optimal value of 2.1973 µm and 0.256 mm were found for surface roughness and flank wear, respectively
Tribological properties of h-BN nanoparticles as lubricant additive on cylinder liner and piston ring
Friction and wear behaviour of different concentrations of hex-boron nitride (h-BN) nanoparticles in engine oil of grade SAE 20W50 were studied at various loads. These tribological studies were conducted using a four-ball wear test machine and a pin-on-disc universal tribometer. Anti-wear properties of SAE 20W50 + h-BN were studied on the four-ball wear test machine as per ASTM D4172 standard. Friction and wear properties of SAE 20W50 + h-BN on piston ring and cylinder liner tribo-pair were studied using the universal tribometer. Nanoparticles of h-BN mixed in lubricant showed excellent tribological performance. In most of the cases, h-BN nanoparticles as additive reduced the wear loss by 30–70% at various loads. The minimum value of coefficient of friction (0.0401) was found with SAE 20W50 + 3 wt% of h-BN at normal load of 100 N. Scanning electron microscopy and Raman spectroscopy were used for characterisation of h-BN and wear scars
Loss of genetic diversity and inbreeding in Kashmir red deer (Cervus elaphus hanglu) of Dachigam National Park, Jammu & Kashmir, India
BACKGROUND: Hangul (Cervus elaphus hanglu), the eastern most subspecies of red deer, is now confined only to the mountains in the Kashmir region of Jammu & Kashmir State of India. It is of great conservation significance as this is the last and only hope for Asiatic survivor of the red deer species in India. Wild population of free ranging hangul deer inhabiting in and around Dachigam National Park was genetically assessed in order to account for constitutive genetic attributes of hangul population using microsatellite markers. RESULTS: In a pool of 36 multi-locus genotypes, 30 unique individuals were identified based on six microsatellite loci. The estimated cumulative probability of identity assuming all individuals were siblings (P(ID) sibs) was 0.009 (9 in 1000). Altogether, 49 different alleles were observed with mean (± s.e.) allelic number of 8.17 ± 1.05, ranging from 5 to 11 per locus. The observed heterozygosity ranged between 0.08 and 0.83, with mean 0.40 ± 0.11 and the inbreeding coefficient ranged between −0.04 and 0.87 with mean 0.38 ± 0.15. Majority of loci (5/6) were found to be informative (PIC value > 0.5). All loci deviated from Hardy-Weinberg equilibrium except Ca-38 (P > 0.05) and none of the pairs of loci showed significant linkage disequilibrium except the single pair of Ca-30 and Ca-43 (P < 0.05). CONCLUSIONS: The preliminary findings revealed that hangul population is significantly inbred and exhibited a low genetic diversity in comparison to other deer populations of the world. We suggest prioritizing the potential individuals retaining high heterozygosity for ex situ conservation and genetic monitoring of the hangul population should be initiated covering the entire distribution range to ensure the long term survival of hangul. We speculate further ignoring genetics attributes may lead to a detrimental effect which can negatively influence the reproductive fitness and survivorship of the hangul population in the wild
Tribological Characterisation of Graphene Oxide as Lubricant Additive on Hypereutectic Al-25Si/Steel Tribopair
The performance of a lubricant greatly depends on the additives it involves. However, recently used additives produce severe pollution when they are burned and exhausted. Therefore, it is necessary to develop a new generation of green additives. Graphene oxide (GO) is considered to be environmentally friendly. The scope of this study is to explore the fundamental tribological behavior of graphene, the first existing 2D material, and evaluate its performance as a lubricant additive. The friction and wear behavior of 0.5 wt% concentrations of GO particles in ethanol and SAE20W50 engine oil on a hypereutectic Al-25Si alloy disc against steel ball was studied at 5 N load. GO as an additive reduced the wear coefficient by 60–80% with 30 Hz frequency for 120 m sliding distance. The minimum value of the coefficient of friction (0.057) was found with SAE20W50 + 0.5 wt% GO. A possible explanation for these results is that the graphene layers act as a 2D nanomaterial and form a conformal protective film on the sliding contact interfaces and easily shear off due to weak Van der Waal's forces and drastically reduce the wear. Scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and Raman spectroscopy were used for characterization of GO and wear scars
Effect of Duration and Amplitude of Direct Current When Lidocaine is Delivered by Iontophoresis
Dosage for the galvanic stimulation for iontophoresis varies. Clinicians manipulate the duration or the amplitude of the current, but it is not known which is more effective. We compared the anesthetic effect of lidocaine HCL (2%) by manipulating the current parameters on 21 healthy volunteers (age: 21.2 ± 4.2, height 170.7 ± 10.2 cm, mass 82.1 ± 19.2 kg). Three conditions were administered in a random order using a Phoresor II® with 2 mL, 2% lidocaine HCL in an iontophoresis electrode. (1) HASD (40 mA*min): High amplitude (4 mA), short duration (10 min); (2) LALD (40 mA.min): Low amplitude (2 mA), long duration (20 min); (3) Sham condition (0 mA, 20 min). Semmes-Weinstein monofilament (SWM) scores were taken pre and post intervention to measure sensation changes. Two-way ANOVA with repeated measures was used to compare sensation. Both iontophoresis treatments: LALD (4.2 ± 0.32 mm) and HASD (4.2 ± 0.52 mm) significantly increased SWM scores, indicating an increase in anesthesia, compared to the sham condition (3.6 ± 0.06 mm) p \u3c 0.05. Neither LALD nor HASD was more effective and there was no difference in anesthesia with the sham. Lidocaine delivered via iontophoresis reduces cutaneous sensation. However, there was no benefit in either a HASD or LALD treatment
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