Acceptance Sampling Plans from Life Tests Based on Percentiles of New Weibull–Pareto Distribution with Application to Breaking Stress of Carbon Fibers Data

In this paper, acceptance sampling plans (ASPs) are proposed for the new Weibull-Pareto distribution (NWPD) percentiles assuming truncated life tests at a pre-determined time. The minimum sample sizes essential to assert the specified percentile are calculated for a given consumer’s risk. The operating characteristic function values of the developed ASPs and producer’s risk are provided. A real data set related to the breaking stress of carbon fibers data are presented for illustration.

Breaking stress of Coulomb crystals in the neutron star crust

It is generally accepted that the Coulomb crystal model can be used to describe matter in the neutron star crust. In [1] we study the properties of deformed Coulomb crystals and how their stability depends on the polarization of the electron background. The breaking stress in the crust σmax at zero temperature was calculated based on the analysis of the electrostatic energy and the phonon spectrum of the Coulomb crystal. In this paper, I briefly discuss the influence of zero-point, thermal contributions and the internal magnetic field on σmax.

Influence of water content on mechanical behaviour of gastropod taenioglossan radulae

One molluscan autapomorphy is the radula, the organ used for feeding. Here, for the first time, the performance and failure of taenioglossan radular teeth were tested in a biomechanical experiment which in turn allowed building hypotheses about tooth functionalities. Shear load was applied to tooth cusps with a force transducer until structural failure occurred, the broken area was measured, and finally breaking stress was calculated. These experiments were carried out under dry and wet conditions. Our results show that certain tooth types can resist higher stresses and are rather specialised to loosen food items from a surface, whereas other teeth can only gather food particles. The experiments additionally illustrate the high influence of the water content on the resulting breaking stress. When wet teeth were tested, their ductility and ability to avoid being fractured by an obstacle increased. Their flexibility also allowed them support from teeth of adjacent tooth rows, which made the whole system less prone to failure. Our results were compared with the previous data on the mechanical properties and feeding simulations. This study provides a keystone for further comparative studies aiming at connecting diversity of radulae with their possible adaptations to the ingesta.

Developing Soybean Protein Gel-Based Foods from Okara Using the Wet-Type Grinder Method

Okara, a by-product of tofu or soymilk, is rich in dietary fibers (DFs) that are mostly insoluble. A wet-type grinder (WG) system was used to produce nanocellulose (NC). We hypothesized that the WG system would increase the dispersion performance and viscosity of okara. These properties of WG-treated okara improve the gel-forming ability of soybean proteins. Here, the suspensions of 2 wt% okara were treated with WG for different passages (1, 3, and 5 times). The particle size distribution (PSD) and viscosity of WG-treated okara decreased and increased, respectively, with different passages. The five-time WG-treated okara homogeneously dispersed in water after 24 h, whereas untreated okara did not. The breaking stress, strain, and water holding capacity of soybean protein isolate (SPI) gels increased upon the addition of WG-treated okara. This effect increased as the number of WG treatments increased. The breaking stress and strain of SPI gels to which different concentrations of the five-time WG-treated okara were added also increased with increasing concentrations of WG-treated okara. These results suggest that NC technology can improve the physicochemical properties of okara and are useful in the development of protein gel-based foods.

Influence of moulding condition on the properties of dressed and functionalized nanocomposites based on low density polyethylene

The results of a study of the effect of injection molding on the physicomechanical and technological properties of nanocomposites based on functionalized low-density polyethylene by maleic anhydride and dressed with talc γ-aminopropyltriethoxysilane are presented. As the object of study, nanocomposites with 5.0 and 30 mass. % of dressed talc were used. Properties such as breaking stress, elongation at break, flexural strength, and volumetric shrinkage were investigated. It was found that the introduction of dressed talc in the composition of chemically modified low density polyethylene contributes to some increase in the breaking stress and the flexural modulus of the nanocomposite. Experimental studies were carried out in a wide range of temperatures of the material cylinder and casting pressure. It was found that comparatively high physical and mechanical properties are achieved in samples obtained at higher temperatures in the zones of the material cylinder. Casting pressure ranged from 50 to 150 MPa. It was found that relatively high physicomechanical and technological properties for nanocomposites with 5.0 and 30 mass. % talc content are achieved at a temperature of the material cylinder in the zones 110 – 130 – 160 – 180 °C and a casting pressure of 150 MPa. A significant reduction in volumetric shrinkage is achieved in samples with 30%mass. talc content. The influence of mold temperature and holding time under pressure on the change in the properties of nanocomposites is considered. It is shown that the most optimal mode in the cooling mold for samples with 5.0 mass. % talc content is 50 °C and the exposure time under pressure is 20 s, and for a nanocomposite with 30%mass. talc content — 50 °C and holding time 10 s. The influence of the location of the gate device relative to the surface of the sample on the change in the properties of composite materials is studied. The scientific substantiation of the discovered patterns in changing the properties of nanocomposites is given.

PREDICTION OF THE BREAKING STRESS OF CLAYEY SOILS FROM TCHI DEPRESSION TO BENIN.

The phenomena of shrinkage and swelling of clay soils depending on the water content are manifested by disorders affecting mainly individual houses, often not very rigid and superficially founded. The superficial foundations of infrastructures built on swelling soils are subjected to several stresses due to shrinkage and swelling phenomena. These stresses are the cause of damage to the frames in the form of cracks, or even lead to the partial or total breakage of the structure when it is built without special precautions. In order to control these induced stresses and to safeguard these infrastructures, it is necessary to control the breaking stress so that the dimensioned foundations do not cause the structure to break. The objective of this study is to develop a model to estimate the breaking stress thanks to the physical parameters of these soils. To achieve this, we performed several physical and mechanical tests on swelling soil samples taken from the study area, the results of which we used to use the established non-linear least squares method of swelling pressure prediction models. The models were based on test results from 24 soil samples. The tests were carried out in accordance with the French NF standards. This study has shown that the shear strength of a soil is a function of several physical parameters, mainly: pre-consolidation stress and plasticity index. We obtained the model qu=(2.9-1.181.IP). σ'p allowing us to predict the shear strength for the study area. This model is obtained with a regression coefficient precision r2 = 98.50%.

Deformed crystals and torsional oscillations of neutron star crust

ABSTRACT We study breaking stress of deformed Coulomb crystals in a neutron star crust, taking into account electron plasma screening of ion–ion interaction; calculated breaking stress is fitted as a function of electron screening parameter. We apply the results for analysing torsional oscillation modes in the crust of a non-magnetic star. We present exact analytical expression for the fundamental frequencies of such oscillations and show that the frequencies of all torsional oscillations are insensitive to the presence of the outer neutron star crust. The results can be useful in theoretical modelling of processes involving deformed Coulomb crystals in the crust of neutron stars, such as magnetic field evolution, torsional crustal, or magneto-elastic quasi-periodic oscillations of flaring soft gamma-ray repeaters, pulsar glitches. The applicability of the results to soft gamma-ray repeaters is discussed.