STRESS INTENSITY FACTORS FOR CRACKS AT FASTENER HOLES

Abstract— Transmission and reflection photoelasticity has been used to determine the stress intensity factors for artificial cracks emanating from a hole in two-dimensional tensile plates. Three geometries were investigated, namely a free hole, a pin-loaded hole and a hole with an interference-fit pin. All these cases relate to situations commonly found in aircraft structures. The results have been compared where possible with analytical data and a good correlation was found for these cases.     

Corn Sweeteners in Ham Formulas

Corn sweeteners were compared with sucrose in cure formulas for hams. Thirty-six hams were randomly treated with nine sweetener treatments replicated four times. Combinations of sucrose, 55% high fructose corn syrup, 42% high fructose corn syrup, and high maltose corn syrup were used in brine formulas for pumping the hams. Sensory evaluations found no significant difference between sweetener type and sensory scores on color, flavor, tenderness, and overall satisfaction. However, ham weights appeared to be affected slightly by sweetener type. Sucrose produced greater ham yields at a 3% sweetener level. However, 55% high fructose corn syrup at 3.15% equalled the yield observed for sucrose. Forty-two percent high fructose corn syrup at greater than 3.3% solid level approached the yields observed for sucrose. Since sensory factors do not appear to be affected by corn syrup solids, only economic and yield factors need bc considered for their use in commercially produced hams.     

The Development of Colour Science

Colour Science has developed over many years as the result of the interaction between a number of penetrating theoretical advances in the understanding of the nature of colour perception and their practical application, made possible by technical advances in optics and electronics. This review traces the development of the subject to its present stage, where colour can be specified and measured numerically, and the results used both in specifying colour tolerances and in predicting colour recipes.     

Observation of Aqueous Dye Dispersions at High Temperature I - Construction of a Simple Microscope Pressure Hot Stage

There is at present, considerable interest in the behaviour of aqueous dye dispersions at high dyeing temperatures and in the variable solution properties of such dispersions prepared from metastable and stable dye solids. Earlier methods to observe dyebath conditions include the Microdyeoscope designed by Millson 1. This required a large dyebath, the solution from which passed through a cell situated in the focal plane of a microscope. The fibre or filament to be dyed was held in the cell. Observation was limited to temperatures of less than 100C. A cell formed within the dyebath by two inverted periscopes facing each other at a fixed distance has also been described 2 which allows the rate of dye concentration change to be determined spectrometrically. More recently Biedermann 3 has used a ‘microautoclave’ in which a composite (Teflon/glass) optical cell enclosed in a metal holder and heated indirectly on a Reichert microscope hot-stage was used for examining crystal growth and habit changes in dye dispersions up to 140C. This autoclave was, however, clumsy to use, the heat transfer to the liquid was poor, and the cell could not easily be scanned. Also the material was not in the normal focal plane of the microscope. In the design described in this paper we have eliminated several of these disadvantages to provide a cell which is more easily scanned and incorporates a combined heating and direct temperature reading control unit.     

Colour Differences in Azo Pigments

Four azo pigments - C.I. Pigment Red 1 and 6, Yellow 1 and Orange 6 - have been prepared using a continuous coupling process under a range of conditions of pH, coupling temperature, concentration and rate of flow. The colour and size distribution of the pigments have been measured, the latter using a modified optical centrifuge for which new conversion factors have been determined. Continuous methods generally give lower particle sizes than comparable batch methods. This is discussed in terms of theories of nucleation and growth, as is the potential industrial application of continuous coupling.     

DAWN OF THE DEAD CITY: AN EXPLORATORY ANALYSIS OF VACANT ADDRESSES IN BUFFALO,NY 2008–2010

ABSTRACT: This article examines residential vacancy patterns in Buffalo, NY, using data from a unique data set. It includes variables from HUD Aggregate USPS Administrative Data on Address Vacancies, the American Community Survey (ACS) 5‐year estimates for 2005–2009, housing choice voucher (HCV) records of local public housing agencies, and municipal in rem property records. Multiple regression is used to identify significant relationships between vacancy patterns, socioeconomic characteristics, and institutional factors. The findings from this analysis suggest that the percent of vacant residential properties increases in census tracts with elevated poverty rates, higher percentages of renters receiving rental assistance, and long‐term vacancies. They also suggest that the percent of abandoned residential properties increases in census tracts with highly concentrated black populations, elevated poverty rates, long‐term vacancies, and higher percentages of business addresses. We conclude that these relationships are unique to older core cities experiencing systemic population and job losses. These cities struggle with a distinct type of long‐term vacant and abandoned structures, which we label zombie properties. They can be contrasted with vacant and abandoned properties in transitional or regenerating areas. We offer recommendations for further analysis of zombie properties in these urban settings.     

Effect of irradiation and chilled storage on the microbiological and sensory quality of a ready meal

The sensory and microbiological quality of both non-irradiated and irradiated cook-chill ready meals consisting of roast beef and gravy, cauliflower and sauce together with roast and mashed potatoes were assessed at intervals during 15 d storage at 2–3°C.
Growth of Pseudomonas spp. caused obvious spoilage of the non-irradiated meals after storage, whereas spoilage was not apparent in the irradiated meals. Irradiation (2 and 3 kGy) reduced the number of microorganisms in the meal to <100 g⁻¹ initially and significant microbial growth did not occur during storage.
Using sensory profiling techniques a trained panel found that the effects of irradiation and chilled storage were most apparent in the cauliflower and potato components and occurred most often in the colour, appearance and textural attributes.
The combination of low dose irradiation and chilled storage effectively controlled microbial growth but changes in the sensory characteristics may limit the potential of irradiation to extend the shelf-life and enhance the safety of this ready meal.     

Transition from Ionic to Electronic Conduction in Pure ThO2 Under Reducing Conditions

Open-circuit emf and ac conductivity studies were conducted on two batches of dense polycrystalline ThO₂. The open-circuit emf data were used to delineate the low- p o₂ ionic domain boundary for "pure" ThO₂, which is presented as a log P_θ line on a log Po₂-1/ T diagram. In addition the ionic conductivity, σ_ion, and the high-Po₂ log P_θ boundary were also determined, mainly from ac conductivity measurements, which also confirmed the Po₂^I/4 dependence of σ_p, the p-type electronic conductivity, shown by other investigators. The main results are, for the first batch, log Pθ= 12.7−220.2 × 10³/4.575T, log σ_ion= 1.9−44.3×10³/4.575T, and log P_θ=−1.0−31.4 × 10³/4.575T; for the second batch, log Pθ=11.2−219.7 × 10³/4.575T, log σ_ion= 1.7−41.6 × 10³/4.575T, and log Pθ=0.6−40.4 × 10³/4.575T. The oxygen permeability of ThO₂ tubes and the oxidation rate constant of Th were predicted from the conductivity and emf data and compared with direct measurements previously reported. The calculated and previously measured permeabilities agreed very well; however, the correlation between the predicted and previously measured oxidation kinetics was somewhat less satisfactory.     

Some experimental observations on crack closure and crack-tip plasticity

This study presents a methodology for evaluating crack closure and the effect of crack-tip plasticity on stress intensity. Full-field displacement maps obtained by digital image correlation are used to obtain the mixed-mode, crack-driving force. The methodology allows the quantification of the effect of a range of contact phenomena: effects arising from interlocking, plastic deformation of crack face asperities and wedging generated as a consequence of sliding displacements of fatigue cracks have been identified. By evaluating the effective crack-tip stress intensity factor, crack opening levels can be quantified for both mode I and mode II. Moreover, the approach can take into account plasticity effects local to the crack in determining the stress intensity factor. All the information can be extracted in a non-contacting fashion with equipment that can be easily incorporated into industrial environments.