Solidification behaviour of eutectic and near eutectic aluminum-copper alloys

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Metallurgy, 1963.Includes bibliographical references (leaves 101-103).by Pradeep Rohatgi.M.S

The study of plasma-boundary interactions Quarterly report, 1 Sep. - 30 Nov. 1967

Electrode drag force measurements in boundary interactions of pulsed accelerator plasm

Listening to loan officers: the impact of commercial credit standards on lending and output

Over most of the last thirty-three years, the Federal Reserve has polled a small number of bank loan officers about their moves to tighten or ease commercial credit standards. Although the Senior Loan Officer Opinion Survey uses a small sample and gathers only qualitative information, it proves to be a useful tool in predicting changes in commercial lending and output. The authors find a strong correlation between tighter credit standards and slower loan growth and output, even after controlling for credit demand and other predictors of lending and output. The analysis also shows that the loan officer reports can help predict narrower measures of business activity, including inventory investment and industrial production.Bank loans ; Business cycles ; Forecasting

Plasma boundary interactions - 2

Model of plasma boundary interaction

Laser-assisted solar cell metallization processing

Laser-assisted processing techniques for producing high-quality solar cell metallization patterns are being investigated, developed, and characterized. The tasks comprising these investigations are outlined

Skillful management of exodontia complication to prevent dreadful sequelae

Successful surgical treatments depend upon accurate diagnosis, judicious treatment planning, selection and execution of an appropriate surgical technique, and on a well monitored post-operative period. However, despite these precautions, extraction of teeth (particularly third molar) is exposed to the accidents and complications common to all buccomaxillary and facial interventions. A maxillary third molar may be displaced in maxillary sinus, nearby soft tissue, or may migrate in a superioposterior direction towards paraphyrangeal space, or infratemporal fossa. Dislocating the maxillary third molar in infratemporal fossa is one of the worst nightmare as this area has complex anatomy consisting of vital neurovascular tissues and complex fascial spaces. The extent of displacement depends upon anatomical conditions as well as direction and amount of force applied. Complication arises from error in judgment, improper use of instruments, the application of extreme force or failure to obtain full visualization before acting. Various researchers have given their opinion regarding immediate or delayed removal of tooth pushed in infratemporal fossa but almost all agree that each case should be weighed independently for risk and reward before attempting. Here we present a case in which intraoral approach was taken to retrieve the displaced tooth thus preventing potentially dreadful complications

Development of high efficiency solar cells on silicon web

Web base material is being improved with a goal toward obtaining solar cell efficiencies in excess of 18% (AM1). Carrier loss mechanisms in web silicon was investigated, techniques were developed to reduce carrier recombination in the web, and web cells were fabricated using effective surface passivation. The effect of stress on web cell performance was also investigated

Directional solidification of aluminum-nickel eutectic alloys using electroslag remelting

Attempts were made to produce directionally solidified, specifically grain aligned Al-6 wt pct Ni eutectic alloy using a laboratory scale ESR unit. For this purpose sand cast alloy electrodes were electroslag remelted under different mold conditions. The grain structure of the ingots obtained from these meltings showed that insulated silica molds gave the best vertical alignment of grains along the length of the ingot. The NiAl3 fibers within the grains tended to fan out and there was only a preferred alignment of fibers along the growth direction under the conditions of our experiments. The ESR parameters most suitable for vertical alignment of eutectic grains have been identified. In some electroslag remelting trials ingots were grown on a seed ingot. This resulted in a fewer vertical grains compared to the case when no seed ingot was used. The sand cast specimen of the eutectic exhibited a maximum tensile strength of around 88.2 MN/m2 (9.0 kg/mm2) whereas conventional ESR using water cooled mold gave strength value of 98.0 MN/m2 (10 kg/mm2). The directionally solidified ESR material showed longitudinal tensile strength as high as 213.7 MN/m2 (21.8 kg/mm2) which could be further increased to 220.6 MN/m2 (22.5 kg/mm2) by using the seed ingot. The average growth rate was varied between 5 to 25 mm/min during electroslag remelting in this study. The flow stresses, tangent modulus and ultimate tensile strength of directionally solidified eutectic increased with increasing growth rates

Dendritic solidification of aqueous solutions.

Massachusetts Institute of Technology. Dept. of Metallurgy. Thesis. 1964. Sc.D.Sc.D