Study of the Properties of Coarse Aggregates

Research Project C-22 is an investigation of the geologic aspects of limestone aggregate that might cause failure if used in highway construction. This represents work being carried on at the Highway Materials Research Laboratory in Lexington. The end point of this work is to determine the cause or causes of failure and provide a test that will delete faulty materials from construction work. In order to evaluate the engineering aspect of the author\u27s work, a study ef the physical tests of these same aggregates is to be made. A correlation between Laboratory Analysis and performance Surveys of these same aggregates in roads should be sufficient to make pertinent observations. Limestone varies in any and all proportions of its basic constituents, with the introduction of some new minerals from time to time. As defined, limestone should be composed of calcium carbonate plus some small amount of impurities. The variation in amount and types of impurity give a limestone its characteristics and this variation is so unique that very rarely will two limestones be identical. The variation in minerals is complex, inasmuch as two different minerals having the same elements, may have entirely different reactions to any influence brought upon them. As to the limits set on the name limestone , the presence of 50% carbonate material should assign a rock as limestone. A chemical analysis, although helpful, will not be a positive criterion as the analysis tells only the compounds present and not the way in which they are combined. It seems a reasonable hypothesis that the impurities present are the dominant agents in any failure of limestone aggregate and a careful comparative study of these impurities should show whether the premise is well founded. This, then, is the main objective of the study

A Study of the Properties of Coarse Aggregates

Research Project C-22 is an investigation of the geologic aspects of limestone aggregate that might cause failure if used in highway construction, as reported earlier. As the study was to be approached from a new standpoint, it was allowed to mature along significant lines. At present a working plan has been adopted and is shown here in some detail

Geologic Considerations in Relation to a Materials Survey

In materials surveying, geology should be of maximum benefit, not as a complete informant but as a foundation for reconnaissance, assembly, and cataloging of materials. Geology in essence is a materials survey on a grand scale. Use of this science for engineering purposes involves some primary knowledge of geologic nomenclature, the basic historic approach of geologists, and the use of resources and data published by state, federal, and private agencies over a period of 75 years. Recognition of the need for information on surface conditions as an aid to engineering and allied sciences is emphasized; and in response to this need, a new system of U.S.G.S. mapping is cited and illustrated in which a special map of surficial geology is prepared in conjunction with the traditional bedrock geologic maps. The importance and the difficulty of converting geologic data to engineering uses are considered, and in lieu of a universally satisfactory means for accomplishing this, a few specific conversions are discussed and illustrated. Each is considered separately from the standpoint of possible materials requirements and the application of geologic methods to the location of usable materials

A Survey of Acidity in Drainage Waters and the Condition of Highway Drainage Installations

Every creek gulley and raw interrupted by roadway fills and embankments must be provided with an adequate drainage conduit under the pavement. If the natural drainage is impeded or the conduit is not functioning properly, impounded water over-runs the pavement, seeps through the fill, and eventually disintegrates the section or reduces its stability. The topography in Kentucky, through varied sectionally, requires on the average, one cross-drain for every thousand feet of roadway. Obviously, these drainage structures are of considerable economic importance in the highway program, not only from the standpoint of initial construction costs, but also from consideration of the service-efficiency or the permanence of the installation itself. Of these two factors, service-efficiency is undoubtedly the more important factor in determining an integrated service economy. Since permanence of a culvert or cross-drain depends largely on the specific properties of the material with which it is made, considerable advantage may be derived by selecting material for use in areas where their properties are compatible with the conditions of service, and excluding them where condition are known to be unfavorable

A Laboratory Investigation of Mineralogical, Chemical and Physical Properties of Limestone Aggregates

The project described in this report represents one phase of comprehensive research with all types of aggregates for highway paving mixtures in Kentucky. It was designed to show the fundamental properties of limestones which determine their suitability for this type of use -- particularly their so-called durability. For this reason, emphasis was placed on analysis of the intrinsic properties of the aggregates themselves rather than analysis of procedures or test methods, such as freezing and thawing

Distributed computer system enhances productivity for SRB joint optimization

Initial calculations of a redesign of the solid rocket booster joint that failed during the shuttle tragedy showed that the design had a weight penalty associated with it. Optimization techniques were to be applied to determine if there was any way to reduce the weight while keeping the joint opening closed and limiting the stresses. To allow engineers to examine as many alternatives as possible, a system was developed consisting of existing software that coupled structural analysis with optimization which would execute on a network of computer workstations. To increase turnaround, this system took advantage of the parallelism offered by the finite difference technique of computing gradients to allow several workstations to contribute to the solution of the problem simultaneously. The resulting system reduced the amount of time to complete one optimization cycle from two hours to one-half hour with a potential of reducing it to 15 minutes. The current distributed system, which contains numerous extensions, requires one hour turnaround per optimization cycle. This would take four hours for the sequential system

Some Chemical, Physical and Mineralogical Features of Soil Colloids

The -1 micron portion of several diversified soils were separated by sedimentary fractionation. Physical properties were evaluated on the -1 micron portion, the +1 micron portion, and on the original -40 sample. The -1 micron portion was analyzed for clay mineral identity by X-ray diffraction, and analyzed chemically for associated materials such as the oxides of Iron, Aluminum, Calcium, and lv!agneeium. These data present several possibilities and trends as to the inter-dependency of the involved variables, other considerations have been devoted to the geologic origin of several samples and to various physico-chemical relationships

Separation, Fractionation and Mineralogy of Clays in Soils

This paper describes a working method for separation, fractionation and identification of colloid and colloidal clay minerals in soils. Technical information pertains to super-centrifugation, electron-microscopy and X-ray diffraction. On the basis of these techniques, twenty-two samples have been investigated in conjunction with a soil stud of pumping pavements. Soils were first dispersed and separated by gravity sedimentation. Fractionation was accomplished by controlled super-centrifugation. The separated fractions were purified and then analyzed by X-ray diffraction. Computed size fractions were checked by shadow castings and lineal dimensions on electron micrographs. Results include identification of the mineral or minerals present and the properties of the natural sample from which the colloidal fractions were extracted. These methods furnish a basis for more extensive research relating the behavior of the clay minerals and their contributions to the properties of soils

Eagles, ravens, and other birds of prey: a history of USAF Suppression of Enemy Air Defense doctrine, 1973-1991

Doctor of PhilosophyDepartment of HistoryDonald J. MrozekDuring the Cold War, the United States’ foreign policy relied heavily on its ability to project military power. More often than not, the central component of force projection rested on the United States military’s effectiveness in employing air power both by establishing air superiority and through accurate delivery of ordnance. As the primary service tasked with conducting aerial warfare, the United States Air Force (USAF) was expected to maintain this capability either to achieve deterrence or, when necessary, to military action. In January 1973, the USAF seemed incapable of performing the latter task due to the North Vietnamese Integrated Air Defense System’s (NV-IAD’s) effectiveness in Operation Rolling Thunder and its successor, Operation Linebacker. Eighteen years later, Air Force aircraft spearheaded the Coalition’s air attack on the Iraqi Integrated Air Defense System (I-IADS) in January 1991. Considered by many to be the most effective air defense system outside the Soviet Union’s, the I-IADS was expected to exact heavy casualties from the allied forces. Instead, in less than twenty days, the USAF’s dominance was so complete that politicians, analysts and military historians quickly proclaimed a “Revolution in Military Affairs” (RMA). The majority of the current historiography credits advances in precision-guided munitions (PGMs), airframes, and computer technology as the impetus for the RMA. Others have claimed that the USAF’s training methodology and construction of advanced training sites such as the Red Flag complex at Nellis Air Force Base were the primary drivers for the Air Force’s success. While acknowledging the role all of these factors played, this dissertation also demonstrates the key role played by the development of Suppression of Enemy Air Defense (SEAD) doctrine from January 1973 through August 1991. In the aftermath of the American war in Vietnam, the Air Force considered defense suppression a tactical task that was secondary to the primary mission of putting ordnance on target. At the end of Desert Storm, proponents of the Air Force’s SEAD doctrine had convincing evidence that an enemy IADS was not just an ancillary weapons array, but functioned a critical national system just like manufacturing, government, or the people’s will. The process by which this viewpoint changed had effects on the development of the United States Air Force’s Cold War conventional capability in general, and the development of training methods, electronic warfare platforms, and modern airframes specifically

Inhibition of Serine Palmitoyl Transferase I Reduces Cardiac Ceramide Levels and Increases Glycolysis Rates following Diet-Induced Insulin Resistance

Objective: Diet-induced obesity (DIO) leads to an accumulation of intra-myocardial lipid metabolites implicated in causing cardiac insulin resistance and contractile dysfunction. One such metabolite is ceramide, and our aim was to determine the effects of inhibiting de novo ceramide synthesis on cardiac function and insulin stimulated glucose utilization in mice subjected to DIO. Materials and Methods: C57BL/6 mice were fed a low fat diet or subjected to DIO for 12 weeks, and then treated for 4 weeks with either vehicle control or the serine palmitoyl transferase I (SPT I) inhibitor, myriocin. In vivo cardiac function was assessed via ultrasound echocardiography, while glucose metabolism was assessed in isolated working hearts. Results: DIO was not associated with an accumulation of intra-myocardial ceramide, but rather, an accumulation of intra-myocardial DAG (2.63±0.41 vs. 4.80±0.97 nmol/g dry weight). Nonetheless, treatment of DIO mice with myriocin decreased intra-myocardial ceramide levels (50.3±7.7 vs. 26.9±2.7 nmol/g dry weight) and prevented the DIO-associated increase in intra-myocardial DAG levels. Interestingly, although DIO impaired myocardial glycolysis rates (7789±1267 vs. 2671±326 nmol/min/g dry weight), hearts from myriocin treated DIO mice exhibited an increase in glycolysis rates. Conclusions: Our data reveal that although intra-myocardial ceramide does not accumulate following DIO, inhibition of de novo ceramide synthesis nonetheless reduces intra-myocardial ceramide levels and prevents the accumulation of intra-myocardial DAG. These effects improved the DIO-associated impairment of cardiac glycolysis rates, suggesting that SPT I inhibition increases cardiac glucose utilization. © 2012 Ussher et al.published_or_final_versio