Analytical techniques: A compilation

A compilation, containing articles on a number of analytical techniques for quality control engineers and laboratory workers, is presented. Data cover techniques for testing electronic, mechanical, and optical systems, nondestructive testing techniques, and gas analysis techniques

Similitude requirements and scaling relationships as applied to model testing

The similitude requirements for the most general test conditions are presented. These similitude requirements are considered in relation to the scaling relationships, test technique, test conditions (including supersonic flow), and test objectives. Particular emphasis is placed on satisfying the various similitude requirements for incompressible and compressible flow conditions. For free flying models tests, the test velocities for incompressible flow are scaled from Froude number similitude requirements and those for compressible flow are scaled from Mach number similitude requirements. The limitations of various test techniques are indicated, with emphasis on the free flying model

A novel powder factor based bench blast design method for large surface coal mines

Large surface coal mines in Wyoming\u27s Powder River Basin ship millions of tons of coal per annum, moving millions of cubic yards of overburden to mine the coal. Much of this volume is blasted in the form of benches, a common mining technique. Increases in production and scale of equipment in the past thirty-five years have created a paradigm shift for drill and blast personnel at these large surface mines, and the explosives industry has yet to create a blast design method specifically tailored for large surface coal mine bench blasting. This research examines the typical scale of bench blasting at large surface coal mines, develops a new method of design tailored for these operations, and tests the new method against two widely accepted traditional blast design methods. Novel contributions of the research include a new universal scale of energy distribution known as Available Energy, and an entirely powder factor based blast design method that uses cut width as part of the design process. Numerical comparison testing is done at both small borehole diameters (corresponding to the original domain of the traditional blast design methods) and at large borehole diameters. A comparison of the new method and existing major methods of traditional blast design is monitored graphically, and linear regression is used to track the improvement of the accuracy of the match. Finally, the new design method is presented in nomograph form to facilitate use in the field. Development of the nomograph is discussed and sample nomographs for specific design conditions are included. Recommendations for future work and broader applications of the Available Energy paradigm are given to conclude the dissertation. --Abstract, page iii

Relationship Between Soil Support Value and Kentucky CBR

Three slightly different correlations between Kentucky CBR\u27s and the AASHO Road Test soil support values were developed. The first relationship was made by assuming a logarithmic scale between Kentucky CBR\u27s of 5.2 and 100, which corresponded to values on the soil support scale of 3 and 10, respectively. The Kentucky CBR of 5.2 was determined by performing tests on the AASHO road subgrade soils. For practical purposes, the AASHO Road Test crushed stone base material was assumed to be a 100 percent CBR material (this assumption was based on CBR data previously reported by Shook and Fang). The second correlation was obtained by assuming a logarithmic scale between Kentucky CBR\u27s of 5.2 and 90, corresponding to values on the soil support scale of 3 and 10, respectively. The third relationship was constructed through computations using actual traffic data, the Kentucky flexible pavement design curves and the AASHO Design Chart (PT = 2.5). Computed soil support values of 3 and 10 corresponded to Kentucky CBR\u27s of 6 and 90, respectively. Computed values of soil support were plotted to an arithmetic scale and Kentucky CBR\u27s were plotted to a logarithmic scale. In a range of Kentucky CBR\u27s varying from about 4 to 40, the relationship was linear, while from 40 to 90, the curve was concave upward. There was reasonable agreement between a Kentucky CBR of 5.2, determined by tests, and 6, determined through computations. Comments are made regarding the Kentucky CBR testing procedure. In particular, it is noted that Nomographs C and D in Appendix A of the AASHO Guide which relate Kentucky CBR\u27s and soil support values are not valid because the Kentucky CBR testing procedure does not permit the substitution of dynamic compaction in lieu of static compaction for molding CBR soil specimens. Several ASTM and Kentucky CBR tests were performed at different molding moisture contents and compactive energies on the AASHO embankment soil, four representative Kentucky soils, and one soil from the state of Ohio. These data were compared to CBR data previously reported by Shook and Fang. For CBR\u27s ranging from about 4 to 12, a relationship was developed between Kentucky and ASTM CBR\u27s. Within this range of values, Kentucky and ASTM CBR\u27s are approximately equal. Molding specimens under the static pressure of 2000 pounds per square inch as used in the Kentucky CBR procedure produced specimens with initial dry densities that averaged about six percent higher than those obtained by AASHO Designation: T99-57. CBR\u27s and axial swell values were also higher. For soil specimens molded at the same initial dry densities, CBR\u27s of statically compacted specimens are distinctively lower than those observed for dynamically compacted specimens. For relatively small decreases in initial dry densities, there were very large decreases in CBR\u27s. This probably accounts for discrepancies that have been observed between field and laboratory CBR\u27s

Development Of Design Criteria For Mechanical Roof Bolting In Underground Coal Mines

In spite of the widespread usage of mechanical roof bolts as a support system in the underground coal mines, the mechanisms by which roof bolts reinforce the mine roof are still not fully understood. The general practices of roof bolting system are largely based on some empirical rules, which tend to either underdesign or overdesign. In order to design the roof bolting system safely and economically, it is essential to understand the flexural behavior of the immediate roof. Based on the strata sequence, the strata in the immediate roof are divided into three types. The flexural behavior of the three strata types are investigated in terms of the following effects: roof span, horizontal stress, thickness and Young\u27s modulus of the lowest stratum. The reinforcement mechanism of suspension effect is analyzed based on beam-column theory. The equations of the maximum bending stress, deflection and transferred bolt load for the bolted strata are derived. In the analysis, the bolt load is assumed to be point load and the horizontal stress is uniformly applied to each stratum. The reinforcement mechanism of friction effect is also investigated. The major function of roof bolting in this case is to create the frictional resistance between the strata by the tensioning of roof bolts, thereby the individual layers are combined into one single thick layer. Based on the results of this research, the bolts should be equally spaced when the immediate roof is reinforced by the suspension effect. However the bolts should be spaced based on equal shear force concept when the immediate roof is reinforced by friction effect. An efficient computer program and nomographs are developed for the determination of proper bolting patterns and bolt tension. It is hoped that this development can lead to maximum safety with minimum cost for the design of roof bolting system in underground coal mines

Visual drainage assessment: A standardised visual soil assessment method for use in land drainage design in Ireland

peer-reviewedThe implementation of site-specific land drainage system designs is usually disregarded by landowners in favour of locally established ‘standard practice’ land drainage designs. This is due to a number of factors such as a limited understanding of soil–water interactions, lack of facilities for the measurement of soil’s physical or hydrological parameters and perceived time wastage and high costs. Hence there is a need for a site-specific drainage system design methodology that does not rely on inaccessible, time-consuming and/or expensive measurements of soil physical or hydrological properties. This requires a standardised process for deciphering the drainage characteristics of a given soil in the field. As an initial step, a new visual soil assessment method, referred to as visual drainage assessment (VDA), is presented whereby an approximation of the permeability of specific soil horizons is made using seven indicators (water seepage, pan layers, texture, porosity, consistence, stone content and root development) to provide a basis for the design of a site-specific drainage system. Across six poorly drained sites (1.3 ha to 2.6 ha in size) in south-west Ireland a VDA-based design was compared with (i) an ideal design (utilising soil physical measurements to elucidate soil hydraulic parameters) and (ii) a standard design (0.8 m deep drains at a 15 m spacing) by model estimate of water table control and rainfall recharge/drain discharge capacity. The VDA method, unlike standard design equivalents, provided a good approximation of an ideal (from measured hydrological properties) design and prescribed an equivalent land drainage system in the field. Mean modelled rainfall recharge/drain discharge capacity for the VDA (13.3 mm/day) and ideal (12.0 mm/day) designs were significantly higher (P < 0.001, s.e. 1.42 mm/day) than for the standard designs (0.5 mm/day), when assuming a design minimum water table depth of 0.45 m

Liqiud-Liquid Extraction as an Alternative Separation Technique for Ethanol-Water Solutions

The feasibility of liquid extraction as an economic alternative to the ternary azeotrope distillation of an ethanol-water fermenta tion mixture was studied. Experimentation included the determination of the attractiveness of the potential solvents Freon TF, 1-pentene, ethyl ether, unleaded gasoline, and #2 diesel fuel. Selectivities and distribution coefficients for these solvents were determined. Analysis included generation of a process flowsheet and the resultant energy requirements and process economics. Unleaded gasoline was selected aver #2 diesel fuel as the more attractive solvent based on the distribution coefficients, and Freon TF, 1-pentene, and ethyl ether were ruled out as potential solvents. A fermentation plant incorporating a gasoline extraction process and a beer still to separate the fermentation mixture, with an ethanol recovery rate of 96 wt%, was found to yield an energy savings of 15.6% over a fermentation plant equipped with only a ternary azeotrope dis tillation separation process. Annual cost for this extraction scheme was found to be $3,998,600, as compared to an annual cost of$1,501,400 for the distillation process. Increasing the recovery rate of ethanol to greater than 99 wt% for the extraction process was suggested as a means to vastly improve its economics. An extraction scheme that did not include the beer still to preconcentrate the alcohol was found to be uneconomical

Erosion Control During Highway Construction: Volume 1

Summary: Highway constuction as we know it today is a high-risk activity with respect to engendering soil erosion. In earlier days of road building, when rights-of-way were generally narrow and excavations mostly shollow, erosion was rarely a serious problem. Only occasionally was it considered necessary to design and apply specific measures for erosion control. With the advent of the superhighway involving far greater widths of right-of-way, and much deeper disturbance of the natural ground to affort the horizontal and vertical highway geometry necessary for high-speed travel, came a several fold increase in erosion potential and a direct need for specific action aimed at its control. Highway engineers have reacted by revising contruction specifications to include many protective measures. In creaseing public awareness of the desireability of protecting the environment has been a source of both support and pressure in the application of erosion control in highway construction. Although improvement has been significant, unwanted soil erosion and accompanying sedimentation resulting from highway construction activity continue to be problems. A lack of knowledge within the highway industry of improved erosion control measures developed outside the industry, perhaps some resistance to change because of a lack of familiarity with erosion control measures, and in some instances a need for information not now available anywhere, are probably the major contributors to continuation of the problem. The present project was directed at improving erosion control practice in highway construction by providing assistance in all three of the foregoing areas contributory to the problem. The principal output of the study is a MANUAL of erosion control principles and practices. The MANUAL focuses on techniques for predicting the erosion potential of highway construction sites, and for estimating the effectiveness of various erosion control measures. A wide variety of control measures are listed and described, and information that will aid in selecting measures to meet specific site requirements is presented. Design standards for control measures, and information on such matters as size selection for mechanical control measures, are not included in the MANUAL because these are already widely available in highway engineering offices. To develop the erosion control MANUAL on which the project effort was centered, means had to be established for estimating the water and wind soil erosion potentials on highway construction sites and the effectiveness of various measures that might be considered for controlling the erosion. The universal soil loss equation

Multi-modal virtual environment research at Armstrong Laboratory

One mission of the Paul M. Fitts Human Engineering Division of Armstrong Laboratory is to improve the user interface for complex systems through user-centered exploratory development and research activities. In support of this goal, many current projects attempt to advance and exploit user-interface concepts made possible by virtual reality (VR) technologies. Virtual environments may be used as a general purpose interface medium, an alternative display/control method, a data visualization and analysis tool, or a graphically based performance assessment tool. An overview is given of research projects within the division on prototype interface hardware/software development, integrated interface concept development, interface design and evaluation tool development, and user and mission performance evaluation tool development

Study of spin-scan imaging for outer planets missions

The constraints that are imposed on the Outer Planet Missions (OPM) imager design are of critical importance. Imager system modeling analyses define important parameters and systematic means for trade-offs applied to specific Jupiter orbiter missions. Possible image sequence plans for Jupiter missions are discussed in detail. Considered is a series of orbits that allow repeated near encounters with three of the Jovian satellites. The data handling involved in the image processing is discussed, and it is shown that only minimal processing is required for the majority of images for a Jupiter orbiter mission