673 research outputs found
Dr Narinder Singh Kapany: Forgotten 'Father of Fiber-Optics'
No full text34-37After the demise of eminent Indian radio-astronomer Prof. Govind Swarup, the scientific community worldwide now mourns another great loss, Dr Narinder Singh Kapany
Aspects of lipid and protein metabolism in the genetically obese Zucker rat
No full textPre-obese fa/fa rats were identified by their decreased rectal temperatures from day 16 onwards. Fatty acid synthesis was measured in vivo by H-incorporation, and in vitro by measurements of the enzymes, glucose-6-phosphate dehydrogense-andfatty acid synthetase. Serum insulin, hepatic and adipose tissue lipogenesis in suckling pre-obese pups were low and similar to lean pups. In rats which had access to the high carbohydrate maternal diet during suckling, adipose tissue lipogenesis was increased to higher levels in pre-obese than lean pups while hepatic lipogenesis was unaltered. Serum insulins rose to similar level in both genotypes. The increased accumulation of 3H-fatty acids in the adipose tissue was shown to be entirely due to de novo synthesis. The excessive accumulation of 3H-fatty acids persisted even when uptake of circulating triglycerides was abolished by the detergent Triton WR 1339. The difference in adipose tissue lipogenesis in pre-weaned lean and pre-obese pups which had access to solid food was not abolished by lowering serum insulins by streptozotocin treatment. Insulin secretory capacity in response to a glucose load was enhanced in pre-obese rats before weaning. A study of the glucocorticoid sensitive hepatic enzymes tyrosine aminotransferase (TAT) and tryptophan dioxygenase (TO) revealed an abnormality in the levels and in the regulation of TAT in the fa/fa rats. Changes in TAT and TO activities were age dependent, and TAT activity was higher in fa/fa rats despite normal serum corticosterone concentrations. The ingestion of solid food was necessary for the elevation of TAT in fa/fa rats. Although the diurnal rhythm of TAT was similar in lean and obese rats, the responses to pair-feeding, to starvation and to tryptophan administration were different in both intact and adrenalectomised obese rats. The response of TO was normal in all the dietary and hormonal influences studied. Both the time course and the dose response curve for the induction of TAT in adrenalectomised rats by corticosterone were different in obese rats. Maximum induction after a single dose (S mg/lOO g body wt.) occurred after 6 hours in lean and after 9 hours in obese rats. The induced levels of TAT in obese rats were 5-6 fold higher than lean values, and were due to increases in the amount of enzyme protein. The half life of TAT was similar in lean and obese rats suggesting that the elevated levels of TAT were due to an increase in enzyme synthesis. The exaggerated responses of TAT to corticosterone in obese rats occurred despite normal glucocorticoid receptor binding. The results are discussed in relation to the altered lipid and protein deposition in the Zucker obese rats, and the role played by adrenal glucocorticoids.</p
On the wear properties of Nylon6-SiC-Al2O3 based fused deposition modelling feed stock filament
No full textFused deposition modelling (FDM) is one of the commonly used additive manufacturing (AM) technologies. In commercial FDM setup a plastic material based filament (usually of ABS) is unwound from a coil to produce functional/non-functional prototypes. The application domain of FDM is limited presently, because of selective material availability in commercial market as regards to the wear of functional prototypes is concerned. In order to enhance the application domain of commercial FDM setup, an effort has been made to develop new polymer composite (with hybrid reinforcement) wire of Nylon6-SiC-Al2O3 with enhanced wear resistant properties. In this research work experimental investigations has been carried out for optimizing wear properties of Nylon6-SiC-Al2O3 based feed stock filament of FDM. Further mathematical model for above mentioned property has been developed and counter verified as a case study
Investigation of torquemeters for high speed shafts
No full textThesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1959Includes bibliographical references (leaves 64-67).by Narinder S. Saluja.B.S.B.S. Massachusetts Institute of Technology, Department of Mechanical Engineerin
Refusals strategies on facebook among primary school children / Narinder Kaur A/P Bakhtawar Singh
No full textThis study investigates refusal strategies on Facebook among primary school children. Based on a Discourse Completion Test (DCT) which has twelve situations, thirty school-going children aged between 11 and 12 years old were asked to construct refusals for the various situations given. For this study, a group of 30 students were asked to respond to the situations where refusals to requests, refusals to suggestions, refusals to invitations and refusals to offers were made. The study aims to explore the types of refusal strategies frequently used by primary school children and what strategies are most revealed in the response to refusals used in the situations given within different settings such as family, formal and social. The data were analyzed and categorized according to the refusal taxonomy by Beebe, Takahashi and Uliss-Weltz (1990). It is found that these primary school children employed more indirect strategies compared to the direct strategies. The high frequency in the use of indirect strategies demonstrates that the subjects were aware of the fact that the use of indirect strategies lessens the face-threatening effect of the speech act of refusals. In fact the indirect strategies, “statement of alternative” enjoyed the highest frequency in the family settings while the indirect strategies “excuse, reasons and explanation” enjoyed the highest frequency in the formal and social settings. Finally, the possible justifications behind the variations in the productions of refusals are discussed.
Key words: speech act, refusals, family settings, formal setting, social setting
Advancements in Lightweight Artificial Aggregates: Typologies, Compositions, Applications, and Prospects for the Future
No full textCurrently, the environment and its natural resources face many issues related to the depletion of natural resources, in addition to the increase in environmental pollution resulting from uncontrolled waste disposal. Therefore, it is crucial to identify practical and effective ways to utilize these wastes, such as transforming them into environmentally friendly concrete. Artificial lightweight aggregates (ALWAs) are gaining interest because of their shift in focus from natural aggregates. Researchers have developed numerous ALWAs to eliminate the need for natural aggregates. This article explores the diverse applications of ALWAs across different industries. ALWAs are currently in the research phase due to various limitations compared to the availability of the various natural aggregates that form more durable solutions. However, researchers have discovered that certain artificial aggregates prioritize weight over strength, allowing for the effective use of ALWAs in applications like pavements. We thoroughly studied the various ALWAs discussed in this article and found that fly ash and construction waste are the most diverse sources of primary material for ALWAs. However, the production of these aggregates also presents challenges in terms of processing and optimization. This article’s case study reveals that ALWAs, consisting of 80% fly ash, 5% blast-furnace slag, and only 15% cement, can yield a sustainable solution. In the single- and double-step palletization, the aggregate proved to be less environmentally harmful. Additionally, the production of ALWAs has a reduced carbon footprint due to the recycling of various waste materials, including aggregates derived from fly ash, marble sludge, and ground granulated blast-furnace slag. Despite their limited mechanical strength, the aggregates exhibit superior performance, making them suitable for use in high-rise buildings and landscapes. Researchers have found that composition plays a key role in determining the application-based properties of aggregates. This article also discusses environmental and sustainability considerations, as well as future trends in the LWA field. Simultaneously, recycling ALWAs can reduce waste and promote sustainable construction. However, this article discusses and researches the challenges associated with the production and processing of ALWAs
sj-docx-1-ajr-10.1177_19458924221105933 - Supplemental material for Efficacy of Vidian Neurectomy and Posterior Nasal Neurectomy in the Management of Nonallergic Rhinitis: A Systematic Review
No full textSupplemental material, sj-docx-1-ajr-10.1177_19458924221105933 for Efficacy of Vidian Neurectomy and Posterior Nasal Neurectomy in the Management of Nonallergic Rhinitis: A Systematic Review by Praween Senanayake, Eugene Wong, Kate McBride and Narinder Singh in American Journal of Rhinology & Allergy</p
Viscosity of blast furnace slags and its effects on their applications
No full textThe paper discusses the effect of chemical and mineralogical compositions and temperature of blast furnace slag on its viscosity. The importance of viscosity of slags with regard to its applications is also stressed on the basis of literature survey. In the production of heavy aggregate and pumice the 'long slags', the viscosity of which increases very slowly in a wide range of temperature, are preferred. For the production of slag cement, the short slags', the viscosity of which is varying fast, are preferred. The viscosity of slag obtained from various iron and steel plants in Poland and East Germany was determined employing the viscometer installed at the Institute, a brief description of which is also given. The graphs for relationship between temperature and viscosity of these slags are reported and the suitability of the slags under study is discussed. (Shri Narinder Singh and Shri Muthukrishnan, Scientists, National Metallurgical Laboratory, Jamshedpur, and Dr. T. Rogozinski, Head of Slag Laboratory, Instytut Metalurgii Zelaza, Gilwice, Poland
Survey of indigenous coals, fly ashes and flue dusts as a potential source of germanium
No full textGermanium occurs in the earth's crust in quantities as much as that of lead and zinc, but there are few concentrated deposits and even in these germanium is only present as a secondary element. This rarer metal occurs in certain coals also, and gets concentrated in the fly ash and flue dust deposited in the chimney, when such coals are used in thermal power stations or gas plants. Fly ash and flue dust are the source of germanium in many parts of the world. A number of collieries were approached and representative samples obtained from them were analysed for germanium to spot out the potential raw material of germanium. The fly ashes and flue dusts obtained from the thermal power station, Gujarat State Electricity Board, Porbander, using coals from Newton Chickely, North Chandamatta and Chandmatta collieries, were found to contain about 200 ppm germanium, which is quite rich in comparison to fly ashes utilized in other countries for extraction of germanium. (Shri Narinder Singh, Scientist; and Shri S.B. Mathur, Senior Scientific Assistant; National Metallurgical Laboratory
Metal matrix composite from recycled materials by using additive manufacturing assisted investment casting
No full textIn this research article, a novel method of additive manufacturing (AM) assisted investment casting (IC) has been demonstrated (by using the patterns prepared from waste materials reinforced with ceramic particles) for development of a metal matrix composite (MMC). In first stage, recycled low density polyethylene (LDPE) has been selected as matrix material, while ceramic reinforcement of SiC and Al2O3 has been blended in LDPE by screw extrusion. Initially, the recycled LDPE has been collected in granules form from the local market and processed on single screw extruder to prepare pallets. The ceramic particles and LDPE were blended together to prepared the final blend in different proportions on twin screw extruder. After that Taguchi L9 orthogonal array has been employed to ascertain the affect of different input parameters of FDM machine to prepare the functional prototypes in the form of cubical patterns. Instead of using conventional IC, a rapid method has been employed to prepare sacrificial pattern by using siladent powder (which is being used for preparing cast in clinical dentistry for dentures). Further this method has been explored as an alternate route of rapid IC, which requires very less time as compared to the traditional methods. At final stage cast were prepared with aluminium (Al) alloy as matrix material reinforced with SiC and Al2O3 (which were present in the mould cavity after removal of LDPE). The properties of MMC prepared via this novel route were subjected to hardness and grain size testing supported by photomicrographs and EDAX analysis
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