Statistical Quality Control of Highway Construction and Materials

The objective of this report is to review existing local practices used in establishing and enforcing highway specifications and construction processes and to compare these practices. With procedures based on statistical quality control concepts. In order that statistical quality control concepts may be properly used where applicable, the first part of this report considers the general theory underlying the use of statistical control methods and the development of different types. Of acceptance plans which may be used in the highway construction industry. The second portion of the report is concerned with analyzing and comparing Kentucky\u27s current specification requirements with typical quality control requirements established using basic statistical theory. Specifications used by some other agencies which are based on statistical principles are presented to illustrate the use being made of this type of acceptance plan. Historical data compiled for various contract items used in highway construction in Kentucky are also presented as background information useful for establishing statistically derived specifications in the future

Kinetic theory of cluster impingement in the framework of statistical mechanics of rigid disks

The paper centres on the evaluation of the function n(theta)=N(theta)/N0, that is the normalized number of islands as a function of coverage 0<theta<1, given N0 initial nucleation centres (dots) having any degree of spatial correlation. A mean field approach has been employed: the islands have the same size at any coverage. In particular, as far as the random distribution of dots is concerned, the problem has been solved by considering the contribution of binary collisions between islands only. With regard to correlated dots, we generalize a method previously applied to the random case only. In passing, we have made use of the exclusion probability reported in [S. Torquato, B. Lu, J. Rubinstein, Phys.Rev.A 41, 2059 (1990)], for determining the kinetics of surface coverage in the case of correlated dots, improving our previous calculation [M. Tomellini, M. Fanfoni, M. Volpe Phys. Rev.B 62, 11300, (2000)].Comment: 10 pages, 3 figure

A Preliminary Evaluation of Mounds to Divert Wayward Vehicles Away from Rigid Obstructions

In the summer of 1965, the first fatality report involving an interstate median bridge pier in Kentucky caused concern among state and national officials for the safety of motorists who perchance or otherwise enter upon a collision course toward an unprotected bridge pier. A consensus of opinion seemed to indicate that some form of attenuation or deflection device was necessary. Early innovations employed various short guardrail configurations to deflect wayward vehicles from the piers. The use of small, short sections has since evolved until present methods include surrounding the bridge pier with several hundred feet of guardrail, including ramped-end treatment (see Figure 1). The use of guardrail has not been questioned from the standpoint of safety design, yet some effort has been applied by Kentucky and other states to finding an alternative approach. From these efforts, the use of mounds to decelerate and deflect vehicles originated. It was thought that this design concept was consistent with current safety developments as well as being an economical treatment of the problem, since most of the work involved in constructing the mound can be done during grade and drain construction using natural materials available on location. These mounds have since been constructed on certain interstate projects and on all bridge locations of the Jackson Purchase (51.4 miles) and Pennyrile (56.6 miles) Parkways in Kentucky. Having found no records of accidents involving these mounds in the interim, there has been no substantial means of evaluating the effectiveness of this innovation in preventing or reducing the severity of collisions with bridge piers. Consequently, it was decided that low speed excursions over a mound might provide a basis for evaluation. The Division of Research made a series of driver-controlled traverses at low speeds on a typical site constructed on a 60-foot median. The purpose of this report is to summarize the results obtained from these initial, low-speed tests and, in so doing, attempt to make some determination of the reliability of this particular type of earthwork. It is anticipated that these low-speed tests will be supplemented eventually by testing at higher speeds, using some form of remote guidance system in place of the human driver. Also, it must be emphasized that conclusions drawn from this report apply only to low-speed encroachments. Additional effects which may be encountered during high-speed testing can only be hypothesized at this time

The Behavior of Coupled Automata

We study the nature of statistical correlations that develop between systems of interacting self-organized critical automata (sandpiles). Numerical and analytical findings are presented describing the emergence of “synchronization” between sandpiles and the dependency of this synchronization on factors such as variations in coupling strength, toppling rule probabilities, symmetric versus asymmetric coupling rules, and numbers of sandpiles

Hydrothermal sensitivities of seed populations underlie fluctuations of dormancy states in an annual plant community

Plant germination ecology involves continuous interactions between changing environmental conditions and the sensitivity of seed populations to respond to those conditions at a given time. Ecologically meaningful parameters characterizing germination capacity (or dormancy) are needed to advance our understanding of the evolution of germination strategies within plant communities. The germination traits commonly examined (e.g., maximum germination percentage under optimal conditions) may not adequately reflect the critical ecological differences in germination behavior across species, communities, and seasons. In particular, most seeds exhibit primary dormancy at dispersal that is alleviated by exposure to dry after-ripening or to hydrated chilling to enable germination in a subsequent favorable season. Population-based threshold (PBT) models of seed germination enable quantification of patterns of germination timing using parameters based on mechanistic assumptions about the underlying germination physiology. We applied the hydrothermal time (HTT) model, a type of PBT model that integrates environmental temperature and water availability, to study germination physiology in a guild of coexisting desert annual species whose seeds were after-ripened by dry storage under different conditions. We show that HTT assumptions are valid for describing germination physiology in these species, including loss of dormancy during after-ripening. Key HTT parameters, the hydrothermal time constant (θHT ) and base water potential distribution among seeds (Ψb (g)), were effective in describing changes in dormancy states and in clustering species exhibiting similar germination syndromes. θHT is an inherent species-specific trait relating to timing of germination that correlates well with long-term field germination fraction, while Ψb (g) shifts with depth of dormancy in response to after-ripening and seasonal environmental variation. Predictions based on variation among coexisting species in θHT and Ψb (g) in laboratory germination tests matched well with 25-yr observations of germination dates and fractions for the same species in natural field conditions. Seed dormancy and germination strategies, which are significant contributors to long-term species demographics under natural conditions, can be represented by readily measurable functional traits underlying variation in germination phenologies.This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

THE IMPLEMENTATION OF A SYSTEMATIC METHOD FOR IDENTIFYING THE ROOT CAUSES OF MANUFACTURING NEGATIVE PROCESS YIELD IN A NORTH AMERICAN FASTENER MANUFACTURING FACILITY

Negative process yield is an unexplained expense that does have a significant impact on profits. As like most other manufacturing processes, there are multiple processing operations that a finished good can be exposed to during the course of the entire process. Negative process yield can occur during these known operations but without accurate reporting and data collection, it becomes a moot point. In order to investigate this unexplainable phenomena properly, understanding of what could possibly cause this from occurring must be achieved. In the case of the North American fastener manufacturing plant, missing pieces that are not accounted for through the normal scrap reporting process are often referred to as “negative process yield”. Loss of material from the various processes has been identified as a problem for the North American fastener manufacturing plant. The set of tools that assist in the identification and steady elimination of waste also referred to as lean principles and techniques must be used during the study. This study will examine and analyze the data collected and associated with the loss of unexplained production pieces throughout the production process and what the financial implications or effects have on margins or profits. The Taguchi Design of Experiment (DOE) method is to be used for the experiment. Roy stated that the main focus of the application of DOE is to improve quality. The definition of quality varies widely depending on the applications, but it must be defined before any experimental technique can be produced with meaningful results. Taguchi offers a generalized definition for quality of performance. He regards performance as the major component of product or process quality. A reduced variation results in a reduction in scrap, less rejection of product, and fewer warranty returns, consequently reducing costs, and improving profits and improving customer satisfaction. The result of the study indicated that the form tool was the most significant factor and the levels or grades of material used for those tools could have an effect on the machining process. There was also an indication that the drilling operation needed to be focused on and that the grade of material used, either carbide or high speed steel, be seriously considered based on the application and desired speeds and feeds of the drill depending on the substrate material of the fastener

Behavior of Coupled Automata

We study the nature of statistical correlations that develop between systems of interacting self-organized critical automata (sandpiles). Numerical and analytical findings are presented describing the emergence of synchronization between sandpiles and the dependency of this synchronization on factors such as variations in coupling strength, toppling rule probabilities, symmetric versus asymmetric coupling rules, and numbers of sandpiles

The influence of maternal glucocorticoids on offspring phenotype in high-and low-risk environments

Elevated maternal glucocorticoid levels during gestation can lead to phenotypic changes in offspring via maternal effects. Although such effects have traditionally been considered maladaptive, maternally derived glucocorticoids may adaptively prepare offspring for their future environment depending upon the correlation between maternal and offspring environments. Nevertheless, relatively few studies test the effects of prenatal glucocorticoid exposure across multiple environments. We tested the potential for ecologically relevant increases in maternal glucocorticoids in the eastern fence lizard (Sceloporus undulatus) to induce adaptive phenotypic changes in offspring exposed to high or low densities of an invasive fire ant predator. Maternal treatment had limited effects on offspring morphology and behavior at hatching, but by 10 days of age, we found maternal treatment interacted with offspring environment to alter anti-predator behaviors. We did not detect differences in early-life survival based on maternal treatment or offspring environment. Opposing selection on anti-predator behaviors from historic and novel invasive predators may confound the potential of maternal glucocorticoids to adaptively influence offspring behavior. Our test of the phenotypic outcomes of transgenerational glucocorticoid effects across risk environments provides important insight into the context-specific nature of this phenomenon and the importance of understanding both current and historic evolutionary pressures

A Blockchain-Based Approach Towards Overcoming Financial Fraud in Public Sector Services

In financial markets it is common for companies and individuals to invest into foreign companies. To avoid the double taxation of investors on dividend payment - both in the country where the profit is generated as well as the country of residence - most governments have entered into bilateral double taxation treaties, whereby investors can claim a tax refund in the country where the profit is generated. Due to easily forgeable documents and insufficient international exchange of information between tax authorities, investors illegitimately apply for these tax returns causing an estimated damage of 1.8 billion USD, for example, in Denmark alone. This paper assesses the potential of a blockchain database to provide a feasible solution for overcoming this problem against the backdrop of recent advances in the public sector and the unique set of blockchain capacities. Towards this end, we develop and evaluate a blockchain-based prototype system aimed at eliminating this type of tax fraud and increasing transparency regarding the flow of dividends. While the prototype is based on the specific context of the Danish tax authority, we discuss how it can be generalized for tracking international and interorganizational transactions

The biomechanics of amnion rupture: an X-ray diffraction study

Pre-term birth is the leading cause of perinatal and neonatal mortality, 40% of which are attributed to the pre-term premature rupture of amnion. Rupture of amnion is thought to be associated with a corresponding decrease in the extracellular collagen content and/or increase in collagenase activity. However, there is very little information concerning the detailed organisation of fibrillar collagen in amnion and how this might influence rupture. Here we identify a loss of lattice like arrangement in collagen organisation from areas near to the rupture site, and present a 9% increase in fibril spacing and a 50% decrease in fibrillar organisation using quantitative measurements gained by transmission electron microscopy and the novel application of synchrotron X-ray diffraction. These data provide an accurate insight into the biomechanical process of amnion rupture and highlight X-ray diffraction as a new and powerful tool in our understanding of this process