An Order-Theoretical Extension of the Guttman Scale to Less Simple Orders

A perfect Guttman scale is rarely found in real data. Pairwise dominance relations between items to be scaled, however, often meet the conditions for less simple orders, such as strict partial orders, interval orders, and semiorders. Examples are thus provided for an extension of the Guttman scale to less simple orders in the framework of ordinal theory, or more specifically, the theory of representations with thresholds. The study is methodologically based on ordering theory. Three illustrative constructions of less simple orders demonstrate that they much more strongly account for real data than do Guttman scales, and that some uniqueness in scale values and thresholds is found in semiorders and interval orders.

     

Disappearance Conditions of Thermal Stress Singularities Based on Stress Intensity in Two and Three-Phase Bonded Structures

The characteristics of stress singularities near the free edge of the interface of bonded dissimilar materials subjected to change in temperature are investigated. The thermal stresses are represented by the sum of the singular terms of types r^-1 and log r, no singular ones and the particular ones. The functions, K × F (j=1,2,3), associated with the terms except the particular terms contributing to the thermal stresses are described as new stress intensity factors. The K is obtained from the technique of the Mellin transform and the F is calculated by numerical analysis such as finite element analysis. The emphasis here is placed on clarifying material combinations with arbitrary wedge angles and elastic properties yielding K = 0. The results can be used to determine material/geometry which ensures that interface residual stresses will be in compressive. This revised version was published online in July 2006 with corrections to the Cover Date.     

Effect of stress ratio on near-threshold propagation of delimination fatigue cracks in unidirectional CFRP

The effect of the stress ratio on near-threshold growth of delamination fatigue cracks was investigated with unidirectional laminates made from Ciba Geigy 914C prepegs (T300/914) and from Toray P305 prepegs (T300/#2500). Tests of delamination fatigue crack propagation were carried out under mode I opening loading by using double cantilever beam specimens. The normalized gradient of energy release range was controlled in load-shedding tests. In the region of crack growth rates above about 5 × 10⁻¹⁰ m/cycle, the growth rate was expressed as a power function of fracture mechanics parameters. Below this region, there existed a growth threshold. The influence of the stress ratio became smaller when the rate was correlated to the energy release rate range than when the rate was correlated to the stress intensity range or the maximum energy release rate. A controlling fracture mechanics parameter is discussed on the basis of fractographic observation and mechanism consideration. A new phenomenological law of fatigue crack propagation is derived.     

A simple facility to measure the scalar neutron spectrum in an assembly

An inexpensive, simple and safe facility was constructed to measure the neutron spectrum in an assembly, by setting a neutron source outside the assembly. A normalization technique for the neutron spectrum and error analyses are mentioned. The error of the calculated spectrometer efficiency is cancelled at the final spectrum normalization. The error caused by the present method is within acceptable levels.     

Changes in the quality of jaboticaba fruit (Myriciaria jaboticaba (Vell) Berg. cv. Sabará) stored under different oxygen concentrations

BACKGROUND: Jaboticaba (Myriciaria jaboticaba (Vell) Berg.) is a highly perishable Brazilian berry with a shelf life of only 2 days under ambient conditions. Low temperatures and controlled atmosphere (CA) have been used to extend the shelf life of perishable fruit. Thus the aim of this study was to determine the effect of CA with varying concentrations of oxygen (1, 5, 10, 15 and 21kPa) during cold storage (12.5 °C) of ‘Sabará’ jaboticaba fruit. RESULTS: Atmospheres with lower oxygen concentrations (1 and 5 kPa O₂) significantly reduced jaboticaba respiration rate. Fruit stored under these conditions had higher L* values, and titratable acidity (TA), and lower ratios of soluble solids content (SSC)/TA. However, at the lowest concentration of oxygen (1 kPa O₂), firmness decreased markedly compared to fruits stored at higher O₂ levels (P < 0.05). After only 2 days of storage at ambient temperature jaboticaba received a score of 1.6 (dislike strongly ? 1) compared to fruit stored under CA, which scored 7.4 (like moderately ? 7). After 9 days of storage, fruit from all treatments remained above the limit of acceptability (score 5) and were rated as 6.2. With respect to appearance, statistical differences between treatments were not observed. The total anthocyanin content was not affected by oxygen concentration but decreased 40.4% during CA storage. CONCLUSION: 'Sabará' jaboticaba fruit can be satisfactorily stored under atmospheres containing 5‐21 kPa O₂ at 12.5 °C for up to 6 days. Copyright © 2011 Society of Chemical Industry     

A case report of pseudohypoparathyroidism (Drezner's type I) associated with probable Bartter's syndrome

A 24-yr-old male patient that suffered from chronic tetany since school age. At the age of 20 tetanic convulsions occurred due to hypocalcemia. His mother also had chronic tetany due to pseudohypoparathyroidism. At the age of 24, hypocalcemia caused by pseudohypoparathyroidism was noted. Hypopotassemia persisted even when the hypocalcemia improved with the administration of 1 alpha-hydroxycholecalciferol and calcium lactate. Other findings were normal blood pressure, high levels of plasma renin activity and serum aldosterone, a fall in blood pressure after angiotensin II antagonist infusion, blunted pressor response to angiotensin II infusion and hyperplasia of the juxtaglomerular cells. These results were compatible with Bartter's syndrome. Plasma prostaglandins E2 and F2 alpha in standing position were suppressed after indomethacin administration. To our knowledge this is thought to be the first report of a case of pseudohypoparathyroidism associated with probable Bartter's syndrome.     

Micro/macro-mechanical approach of first ply failure in CFRP

A combined experimental and numerical study has been carried out in order to predict initial failure in transversely loaded carbon fibre/epoxy composites. Three-point bending experiments on macroscopic composite specimens with special laminate lay-ups were carried out in a scanning electron microscope (SEM). The in-situ experiments allow observing the onset of microscopic composite failure under transverse loading and measurement of the global applied load at onset of failure. The experimental results show that interfacial failure was the dominating failure mechanism. The interfacial stresses at initiation of failure were determined successfully by a non-linear micro/macro FE-Analysis and compared with experimental results obtained from 3-point bending tests of standard composite specimens. The results show that the interfacial normal strength (INS) governs the failure process.     

Reduction in energy release rate for mode I fracture of a fibre with a cracked coating layer due to small-scale interfacial debonding

In order to predict the effect of small-scale interfacial debonding on the energy release rate at a crack tip for mode I fracture of a fibre with a cracked coating layer, an approximate calculation method has been presented. The relation of debonding length, thickness of the coating layer and ratio of elastic modulus of the coating layer to that of the fibre, to the energy release rate of the fibre was calculated for some examples. It was demonstrated that small-scale debonding reduces the energy release rate and, therefore, effectively prevents reduction in fibre strength.