Cracking is one of the main causes requiring replacement of asphalt pavement, but the traditional mix design methodologies do not require testing of asphalt mixture cracking resistance. Two cracking ...tests, Thermal Stress Restrained Specimen Test (TSRST) and Semi-Circular Bending (SCB), were evaluated in this study to determine their suitability for adapting as part of mixture type testing and quality control protocol. Eight different mixtures were used to evaluate the test methods, having a wide range of maximum aggregate size, mix type, binder grade and target application. Half of the mixtures were plant-produced, while the other half were laboratory-produced. The results showed that TSRST is the preferred method for mix design because of smaller result variability and better distinguishing between the different mixtures. At the same time, a reasonable correlation exists between TSRST and SCB tests. This makes it possible to use the simpler SCB test for pre-screening samples to further test using the TSRST. The equivalent ageing protocol is a pre-requisite to be able to compare the test results. The fraass breaking point, a measure of bitumen low-temperature cracking resistance, did not provide good correlation with either of the mixture cracking tests.
In this study, a new class of magnetorheological (MR) damper, which can realize desired damping force at both low and high speeds of vehicle suspension systems, is proposed and its salient ...characteristics are shown through computer simulations. Unlike conventional MR dampers, the proposed MR damper has a specific pole shape function and therefore the damping coefficient is changed by varying the effective area of the main orifice. In addition, by controlling the opening or closing the bypass orifice, the drastic change of the damping coefficient is realizable. After briefly describing the operating principle, a mathematical modeling is performed considering the pole shape function which is a key feature of the proposed MR damper. Then, the field-dependent damping force and piston velocity-dependent characteristics are presented followed by an example on how to achieve desired damping force characteristics by changing the damping coefficient and slope breaking point which represents the bilinear damping property.
Long before reaching its mechanical breaking point, a bio-system begins responding to stress at its own “bio-functional breaking point,” a phase of life activity dysfunction. However, little is known ...about the correlation between tissue flexibility and the conditions under which cellular response, damage, and death occur. We are now developing a new confocal microscopy-based observation method to analyze cell aggregates (spheroids) that are under physical pressure. The method concomitantly assesses cellular responses, stress levels, and cellular structure changes. Using this method, we found that the artificial suppression of the gene expression of fibronectin, a major component of the extracellular matrix, provides different mechanical characteristics to hepatoma-derived cell line spheroids than does the control wild type. This study may aid in the prediction of the characteristics of a tissue of interest by simply analyzing the tissue gene expression pattern, providing valuable information for the development and operation of wearable devices. It may also help in the preparation of custom devices that suit specific individuals.
The objective of this study was to study and compare the impact of HMT on rheology and textural properties observed between sago and arenga starces, and then related to structural change of ...amylopectin. The HMT were conducted using the autoclaving method at 20% moisture content and heated to 120 C for 60 min for sago and 90 min for arenga starch as optimum condition. The HMT shifted gelatinization temperature higher and reduced the enthalpy of both starches. The HMT sago starch paste exhibited an exceptionally strong shear thinning behavior as shown by a rapid decrease of viscosity and an increase of shear rate. The HMT clearly made the texture of starch gels more fragile compared to their native form and reduced their breaking point to a lower strain. The HMT effect on the rheological properties and texture of the sago starch was greater than the changes observed with the arenga starch. Major changes in rheological properties after HMT was not followed by changes in amylopectin structure. The HMT process did not significantly affect the amylopectin chain-length distribution in Arenga starch. In the sago starch, HMT affect to long chain amylopectin with DP ≥ 37. The HMT effect on rheology and textural properties was higher in sago starch than arenga starch. This study demonstrated that long chain amylopectin with DP ≥ 37 plays an important role in contributing to the rheological change caused by the HMT.
► ANN method was employed to model polymer modified bitumen properties. ► Fraass breaking point, creep stiffness and creep rate were the desirable properties. ► An appropriate architecture has been ...obtained to predict desirable properties. ► Accuracy and authenticity of simulation process was confirmed.
Improving bitumen properties by using polymeric materials such as ethylene butyl acrylate, styrene–ethylene–butylene–styrene, ethylene vinyl acetate and styrene–butadiene–styrene has been reported by the researchers. To avoid practical measuring difficulties, Artificial Neural Network has been employed to predict the properties. The presented study, by employing practical data obtained by the researchers and using MATLAB program, has suggested models to predict physical–mechanical properties of modified bitumen. In the process, an appropriate architecture has been obtained to predict each of desirable properties by using try and error method. Comparing the model results with experimental data showed the high acceptability of the suggested models.
•Multimorbidity prevalence increases at an early age, starting from the age of 28.•Multimorbidity prevalence increases most between 28 and 51 years of age.•Aiming for a considerable delay, current ...treatment and disease prevention strategies should focus on a complex approach towards a rather healthy young population.
Multimorbidity – the coexistence of ≥2 chronic conditions in same individual is usually associated with older age. There is an increase in its prevalence at a much younger age, however with very limited research specifying that.
To identify age breaking points for the occurrence of multimorbidity.
The study included patients, who used any healthcare services between the 01/01/2012 and 30/06/2014. Patients were divided into two groups – with single chronic condition and with multimorbidity. Age-specific proportion of multimorbidity, rate of primary and outpatient visits, number of hospitalizations and prescribed reimbursed medications between these groups were analyzed.
The study included 452578 patients, 94.63% of them had more than one chronic condition. The risk increase with every consecutive year for developing multimorbidity was between the age of 28 and 39 years. The age breaking point for the rapid increase in hospitalizations was about 29 years in multimorbidity group. The proportion of patients with multimorbidity using expensive medications starts to increase at the age of 41.
The risk of acquiring an additional chronic condition rises exponentially from the age of 29 years and platos between the age of 51 and 57. Patients with multimorbidity require increasing amounts of primary healthcare resources, where patients with single chronic condition require decreasing primary care usage, possibly attributed to successful patient empowerment.
We determine the finite groups whose poset of conjugacy classes of subgroups has breaking points. This leads to a new characterization of the generalized quaternion 2-groups. A generalization of this ...property is also studied.
The bank slopes in hydro-fluctuation areas of reservoirs or lakes suffer from severe erosion due to an absence of protection. Waves are one of the important external forces that cause bank erosion ...and slope failures. However, the processes and quantified impacts of wave-induced erosion on slopes remain unclear under different water level-fluctuation conditions. This paper focuses on the characteristics of wave-induced slope erosion under three conditions: water level dropping (WLD), fixed (WLF) and rising (WLR). A steel tank with glass pane was used to simulate the wave-induced slope erosion in the three treatments. The slope elevation data were collected by using the method of the pin meter for every 15 minutes from the beginning to the end, a total of 5 times during all treatments. These data were processed by using software (SURFER 9.0) to get the slope micro-topography and the erosion volume. Then the temporal and spatial change of slope erosion was analysed according to the erosion amount or erosion rate calculated based on bulk density of slope soil. The results demonstrated that the soil erosion rates for different water level changing treatments are in the following order: WLR>WLD>WLF. For the erosion spatial variation, the middle part of the slope was the major source of sediment in the WLD. The upper part of the slope was the major source of the sediment for the other two treatments. Compared with the standard deviation (SD), the coefficient of variation (CV) based on the SD is more representative of variations in the soil surface roughness (SSR). Furthermore, the good fit between the SSR and soil erosion rate have the potential to be used to predict soil erosion. Above all, the injection angle of the wave determined the rate of erosion to some extent, and the fall-back flow of the wave could also influence the extent of erosion, deposition, and bank morphology. It is vital to choose the appropriate index (SD or CV) in the three water levels to improve the prediction accuracy. This paper could provide scientific knowledge to manage reservoirs or river banks.
The performance of some commonly used quantum-chemical methods in accurately and reliably describing the influence of applying an external mechanical force has been investigated for a set of small ...molecules. By applying coupled-cluster CCSD(T) theory in an extended basis set as benchmark, all methods tested provide a good qualitative description of the physical process, although the quantitative agreement varies considerably. Hartree-Fock (HF) theory overestimates both the values of the bond-breaking point and the rupture force, typically by 20-30%. The same applies to density-functional theory (DFT) based on the local density approximation (LDA). By introducing the generalized gradient approximation (GGA) in the form of the BLYP and PBE functionals, only a slight overestimation is observed. Moreover, these pure DFT methods perform better than the hybrid B3LYP and CAM-B3LYP methods. The excellent agreement observed between the CCSD(T) method and multiconfigurational methods for bond distances significantly beyond the bond-breaking point shows that the essence of mechanical bond breaking is captured by single-reference-based methods. Comparisons of accurate numerical bond-dissociation curves with simple analytical forms show that Morse-type curves provide useful approximate bond-breaking points and rupture forces, accurate to within 10%. By contrast, polynomial curves are much less useful. The outcome of kinetic calculations to estimate the dissociation probability as a function of the applied force depends strongly on the description of the potential-energy curve. The most probable rupture forces calculated by numerical integration appear to be significantly more accurate than those obtained from simple analytical expressions based on fitted Morse potentials.
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