Statistical analysis of X-40 (Stellite-31) production blends.

An investigation was undertaken to statistically analyze the data obtained on X-40 (Stellite 31) production blends which were tested to the requirements of AMS 5382. For our purpose a blend is one or more furnace heats, the shot of which has been thoroughly mixed to produce greater uniformity of product. The mixed shot is charged to the arc furnaces and cast into parts, and test specimens. A great range of test results have been obtained in testing blends, and it was felt that a statistical analysis of a few of the variables might yield information which could be applied toward improving the general quality and performance of this alloy, particularly with respect to stress rupture time. While blended shot produces more uniformity of product than unblended shot, the spread of values obtained, particularly in stress rupture testing, is still considerable. Factors such as variation in composition, grain size and carbide spacing, were felt to be likely quantities which could possibly be found to influence the properties of Stellite 31, if the masking effects of the many variables present could be reduced or eliminated. To do this by a test program would be nearly impossible and prohibitive in cost. Statistical analysis would accomplish the purpose of indicating trends and tell us which basic factors should be concentrated upon, and perhaps permit a more scientific approach after the variables of little or no significance were eliminated. Some of these complex factors involve variations in processing, and some involve an almost infinite number of minor variations in relative chemical composition. In fact, no two production blends have been observed to date which permit direct comparison of one blend to another. In any alloy containing some ten chemical elements phase relationships may become very sensitive to slight composition shifts of any single element. Phase stability, of course, often reflects on the properties obtained. Since statistics in metallurgy is a tool and not an end in itself the statistical methods used are necessarily of a rudimentary nature. In this work a combination of arithmetic and graphical methods has been used, the arithmetic mean and value of the standard deviation being determined mathematically for the purpose of eliminating guess work in determining the slope and location of the distribution line. The graphical method has been used to plot the test data, confidence limits as calculated, and to illustrate the variations in accordance with the method described by L.R. Hill and P.L. Schmidt and by P.L. Schmidt --Introduction, pages 1-2

Lactation Curves of Holstein Cows as Influenced by Age, Gestation, and Season of Freshening

Lactation curves of dairy cows have been studied by dairy scientists for many years. The effects of various hereditary end non-hereditary influences on the lactation curve have been observed. Factors have been developed to standardize production to a common basis, correcting for differences in age, length of lactation, milking per day, gestation and environment

Effect of chromium, molybdenum, tungsten, and vanadium additions on the physical properties of 1.4 percent titanium-copper

Titanium, an element reported to be ninth most abundant of the elements in the earth\u27s crust, has received very little experimental attention as an alloying element in non-ferrous metallurgy. In copper, titanium produces an age-hardening effect, which makes it of great value to copper manufacturers of fabricated products. Yet, but a handfull of men have investigated the copper-titanium equilibrium diagram, and the titanium rich portion of the diagram still remains a mystery. No work has been done on ternary alloys of copper-titanium to this date, as far as recorded information is concerned, and it is hoped that the present work will, perhaps, throw a faint light on the possibilities of these alloys --Introduction, page 1

Correlation length and compressibility for polar fluids near their critical points

Ph.D.Donald C. O'She

Coastal Issues and Management Strategy for Sagar Island in Bay of Bengal

Sagar Island, situated in the east coast of India is one of the biggest deltaic Islands in Sundarban group. This Island is unique with its natural ecosystem and has a potential for becoming a prime eco-tourism destination. The natural and man-made problems affect the quality of environment and life of people in Sagar Island. This paper examines the severe coastal issues of Sagar Island that include coastal erosion, threat to biodiversity, natural hazards, tourism and livelihood insecurity of local communities.  It recommends adoption of a management strategy by implementing the Integrated Coastal Zone Management (ICZM) in order to mitigate these coastal issues and to ensure sustainable development of the coastal environment of Sagar Island in Sundarban Biosphere Reserve

The Calling Network: A Global Telephone Utility

There is a very large demand for basic telephone service in developing nations, and remote parts of industrialized nations, which cannot be met by conventional wireline and cellular systems. This is the world\u27s largest unserved market. We describe a system which uses recent advances in active phased arrays, fast-packet switching technology, adaptive routing, and light spacecraft technology, in part based on the work of the Jet Propulsion Laboratory and on recently-declassified work done on the Strategic Defense Initiative, to make it possible to address this market with a global telephone network based on a large low-Earth-orbit constellation of identical satellites. A telephone utility can use such a network to provide the same modem basic and enhanced telephone services offered by telephone utilities in the urban centers of fully-industrialized nations. Economies of scale permit capital and operating costs per subscriber low enough to provide service to all subscribers, regardless of location, at prices comparable to the same services in urban areas of industrialized nations, while generating operating profits great enough to attract the capital needed for its construction. The bandwidth needed to support the capacity needed to gain those economies of scale require that the system use Ka-band frequencies. This choice of frequencies places unusual constraints on the network design, and in particular forces the use of a large number of satellites. Global demand for basic and enhanced telephone service is great enough to support at least three networks of the size described herein. The volume of advanced components, and services such as launch services, required to construct and replace these networks is sufficient to propel certain industries to market leadership positions in the early 21st Century

Meso-scale FDM material layout design strategies under manufacturability constraints and fracture conditions

In the manufacturability-driven design (MDD) perspective, manufacturability of the product or system is the most important of the design requirements. In addition to being able to ensure that complex designs (e.g., topology optimization) are manufacturable with a given process or process family, MDD also helps mechanical designers to take advantage of unique process-material effects generated during manufacturing. One of the most recognizable examples of this comes from the scanning-type family of additive manufacturing (AM) processes; the most notable and familiar member of this family is the fused deposition modeling (FDM) or fused filament fabrication (FFF) process. This process works by selectively depositing uniform, approximately isotropic beads or elements of molten thermoplastic material (typically structural engineering plastics) in a series of pre-specified traces to build each layer of the part. There are many interesting 2-D and 3-D mechanical design problems that can be explored by designing the layout of these elements. The resulting structured, hierarchical material (which is both manufacturable and customized layer-by-layer within the limits of the process and material) can be defined as a manufacturing process-driven structured material (MPDSM). This dissertation explores several practical methods for designing these element layouts for 2-D and 3-D meso-scale mechanical problems, focusing ultimately on design-for-fracture. Three different fracture conditions are explored: (1) cases where a crack must be prevented or stopped, (2) cases where the crack must be encouraged or accelerated, and (3) cases where cracks must grow in a simple pre-determined pattern. Several new design tools, including a mapping method for the FDM manufacturability constraints, three major literature reviews, the collection, organization, and analysis of several large (qualitative and quantitative) multi-scale datasets on the fracture behavior of FDM-processed materials, some new experimental equipment, and the refinement of a fast and simple g-code generator based on commercially-available software, were developed and refined to support the design of MPDSMs under fracture conditions. The refined design method and rules were experimentally validated using a series of case studies (involving both design and physical testing of the designs) at the end of the dissertation. Finally, a simple design guide for practicing engineers who are not experts in advanced solid mechanics nor process-tailored materials was developed from the results of this project.U of I OnlyAuthor's request

Slow Conduction through an Arc of Block: A Basis for Arrhythmia Formation Post-Myocardial Infarction

Introduction The electrophysiologic basis for characteristic rate-dependent, constant-late-coupled (390 + 54 milliseconds) premature ventricular beats (PVBs) present 4–5 days following coronary artery occlusion were examined in 108 anesthetized dogs. Methods and results Fractionated/double potentials were observed in injured zone bipolar and composite electrograms at prolonged sinus cycle lengths (1,296 ± 396 milliseconds). At shorter cycle lengths, conduction of the delayed potential decremented, separating from the initial electrogram by a progressively prolonged isoelectric interval. With sufficient delay of the second potential following an isoelectric interval, a PVB was initiated. Both metastable and stable constant-coupled PVBs were associated with Wenckebach-like patterns of delayed activation following an isoelectric interval. Signal-averaging from the infarct border confirmed the presence of an isoelectric interval preceding the PVBs (N = 15). Pacing from the site of double potential formation accurately reproduced the surface ECG morphology (N = 15) of spontaneous PVBs. Closely-spaced epicardial mapping demonstrated delayed activation across an isoelectric interval representing “an arc of conduction block.” Rate-dependent very slow antegrade conduction through a zone of apparent conduction block (N = 8) produced decremental activation delays until the delay was sufficient to excite epicardium distal to the original “arc of conduction block,” resulting in PVB formation. Conclusion The present experiments demonstrate double potential formation and rate-dependent constant-coupled late PVB formation in infarcted dog hearts. Electrode recordings demonstrate a prolonged isoelectric period preceding PVB formation consistent with very slow conduction (<70 mm/s) across a line of apparent conduction block and may represent a new mechanism of PVB formation following myocardial infarction

A monoclonal antibody directed to N-acetylneuraminosyl-alpha 2 leads to 6-galactosyl residue in gangliosides and glycoproteins

This research was originally published in the Journal of Biological Chemistry. S Hakomori, C M Patterson, E Nudelman and K Sekiguchi. A monoclonal antibody directed to N-acetylneuraminosyl-alpha 2 leads to 6-galactosyl residue in gangliosides and glycoproteins. J. Biol. Chem. 1983; 258: 11819-11822 © the American Society for Biochemistry and Molecular Biolog