Search results

The matter of predicting disasters has always been one of the hottest and most challenging tasks in geology. Earthquakes are among the most destructive ones among all the natural hazards. Occurring often without any warning, they are the most feared and unpredictable natural phenomena. In recent years with the emergence of new remote sensing instruments and techniques, geologists interested themselves to define accurate and reliable procedures to foresee disasters using this new technology. This paper aims to examine some of the data that have been used so far in earthquake prediction as well as cheap, relevant remotely sensing and geographic information systems methods to acquire and manipulate data.

Earthquakes are not the same in terms of origins, places (depth) and effects. So after having a brief look at the earthquakes, this paper examines the data that can be used for predicting earthquakes and reviews some of the remote sensing methods used to predict tectonic earthquakes. According to the types of measurements, remote sensing methods can be categorized in three main types; crust displacement, thermal and electromagnetic detecting techniques. Regarding the area's geological characteristics, satellites with optical and/or synthetic aperture radar sensors applications in prediction of large‐scale natural disasters will be discussed.

Presentation of the definitions and characteristics of earthquakes, categorized representation of the types of data used in this field as well as the types and names of the ground, aerial‐ and space‐borne data providers are the most important products of this review paper.

This method, if fully and systematically conducted, can be the cornerstone of an earth‐predicting system.

This mathematical analysis has been accomplished for the purpose of understanding the propagation behaviour like phase velocity and attenuation of Love-type waves through visco-micropolar composite Earth’s structure.

The considered geometry of this problem involves a micropolar Voigt-type viscoelastic stratum imperfectly bonded to a heterogeneous Voigt-type viscoelastic substratum. With the aid of governing equations of motion of each individual medium and method of separation of variable, the components of micro-rotation and displacement have been obtained.

The boundary conditions of the presumed geometry at the free surface and at the interface, together with the obtained components of micro-rotation, displacement and mechanical stresses give rise to the determinant form of the dispersion relation. Moreover, some noteworthy cases have also been extrapolated in detail. Graphical interpretation irradiating the impact of viscoelasticity, micropolarity, heterogeneity and imperfectness on the phase velocity and attenuation of Love-type waves is the principal highlight of the present study.

In this study, the influence of the considered parameters such as micropolarity, viscoelasticity, heterogeneity, and imperfectness has been elucidated graphically on the phase velocity and attenuation of Love-type waves. It has been noticed from the graphs that with the rising magnitude of micropolarity and heterogeneity, the attenuation curves shift upwards, that is the loss of energy of these waves takes place in a rapid way. Hence, from the outcomes of the present analysis, it can be concluded that heterogeneous micropolar stratified media can serve as a helpful tool in increasing the attenuation or in other words, loss of energy of Love-type waves, thus reducing the devastating behaviour of these waves.

Till date, the mathematical modelling as well as vibrational analysis of Love-type waves in a viscoelastic substrate overloaded by visco-micropolar composite Earth’s structure with mechanical interfacial imperfection remain unattempted by researchers round the globe. The current analysis is an approach for studying the traversal traits of surface waves (here, Love-type waves) in a realistic stratified model of the Earth’s crust and may thus, serves as a dynamic paraphernalia in various domains like earthquake and geotechnical engineering; exploration geology and soil mechanics and many more, both in a conceptual as well as pragmatic manner.

The purpose of this paper is to investigate the effect of reinforcement, inhomogeneity and initial stress on the propagation of shear waves. The problem consists of magneto poroelastic medium sandwiched between self-reinforced medium and poroelastic half space. Using Biot’s theory of wave propagation, the frequency equation is obtained.

Shear wave propagation in magneto poroelastic medium embedded between a self-reinforced medium and poroelastic half space is investigated. This particular setup is quite possible in the Earth crust. All the three media are assumed to be inhomogeneous under initial stress. The significant effects of initial stress and inhomogeneity parameters of individual media have been studied.

Phase velocity is computed against wavenumber for various values of self-reinforcement, heterogeneity parameter and initial stress. Classical elasticity results are deduced as a particular case of the present study. Also in the absence of inhomogeneity and initial stress, frequency equation is discussed. Graphical representation is made to exhibit the results.

Shear wave propagation in magneto poroelastic medium embedded between a self-reinforced medium, and poroelastic half space are investigated in presence of initial stress, and inhomogeneity parameter. For heterogeneous poroelastic half space, the Whittaker’s solution is obtained. From the numerical results, it is observed that heterogeneity parameter, inhomogeneity parameter and reinforcement parameter have significant influences on the wave characteristics. In addition, frequency equation is discussed in absence of inhomogeneity and initial stress. For the validation purpose, numerical results are also computed for a particular case.

Gluten-free (GF) foods have gained momentum among consumers due to an increase in incidence and awareness of gluten sensitivity and intolerance. Millet is a GF grain with nutritive qualities comparable to other cereals. However, it was not clear how millet-based GF products would be accepted, leading to the goal of this research. Therefore, the purpose of this paper is to evaluate the effect of formulation on physical properties and consumer preference of millet-based GF bread.

Three bread formulations were used: proso millet flour (100 percent), proso millet flour–corn starch (1:1), and proso millet flour–potato starch (1:1). Physical and sensory properties were statistically evaluated.

Starch addition to the bread formulation had a significant influence on bread volume, color and firmness. A consumer’s age, gluten intolerance and familiarity with millet products did influence the frequency of consumption of GF products. Gluten-intolerant panelists consumed GF products more often than others who are not. Older panelists reported consuming more GF products than younger panelists. Gender also had a significant effect on consumers’ preference for overall acceptability and crumb aroma. The formulation had a significant effect on consumers’ preference of crust color and crumb aroma.

The paper presents an understanding of how starch addition modulates bread properties for the GF market.

In this paper, the authors explored a novel approach to use different starches and proso millet for making GF bread and determined sensory responses based on demographics like age, celiac diagnosis and familiarity with GF foods. This vital information will help processors to determine the portion of the market to target and the formulation to explore further.

The main purpose of this paper is to present and use the particle simulation method to explicitly simulate the spontaneous crack initiation phenomenon in brittle materials, and to compare the particle simulation results with experimental ones on the laboratory scale.

Using the particle simulation method, the brittle material is simulated as an assembly of particles so that the microscopic mechanism of inter‐ and intra‐particle crack initiation can be straightforwardly considered on the microscopic scale. A laboratory test has been conducted using a gypsum sample model to validate the particle simulation method for explicitly simulating the spontaneous crack initiation phenomenon.

The paper finds that in terms of simulating the macroscopic sliding surface along or around the contact plane between a block and its foundation, both the laboratory test and the particle simulation have produced consistent results. This indicated that the particle simulation method is capable of simulating macroscopic cracks through simulating conglomerations and accumulations of microscopic crack initiation within the brittle material. Compared with other numerical methods, the particle simulation method is more suitable for explicitly and effectively simulating spontaneous crack initiation problems on the microscopic scale in brittle materials.

The particle simulation method can be used to explicitly and effectively simulate the spontaneous crack initiation on the microscopic scale in brittle materials. It can be also used to simulate the macroscopic sliding surface along or around the contact plane between a block and its foundation. The experimental results of simulating the spontaneous crack initiation on the laboratory scale in brittle materials are very valuable for validating the numerical simulation results obtained not only from the particle simulation method, but also from other numerical simulation methods.

This paper aims to study using a mobile manipulator with a collaborative robotic arm component to manipulate objects beyond the robot’s maximum payload.

This paper proposes a single-short probabilistic roadmap-based method to plan and optimize manipulation motion with environment support. The method uses an expanded object mesh model to examine contact and randomly explores object motion while keeping contact and securing affordable grasping force. It generates robotic motion trajectories after obtaining object motion using an optimization-based algorithm. With the proposed method’s help, the authors plan contact-rich manipulation without particularly analyzing an object’s contact modes and their transitions. The planner and optimizer determine them automatically.

The authors conducted experiments and analyses using simulations and real-world executions to examine the method’s performance. The method successfully found manipulation motion that met contact, force and kinematic constraints. It allowed a mobile manipulator to move heavy objects while leveraging supporting forces from environmental obstacles.

This paper presents an automatic approach for solving contact-rich heavy object manipulation problems. Unlike previous methods, the new approach does not need to explicitly analyze contact states and build contact transition graphs, thus providing a new view for robotic grasp-less manipulation, nonprehensile manipulation, manipulation with contact, etc.

This paper aims to present an associated methodology to evaluate the initial stress of coal-rock masses in steeply inclined coal seams.

On the basis of the real-time monitoring data in the field, the corresponding analytical analysis is carried out in consideration of the characteristics of topography and geology, so as to deduce the value of the initial stress in the study area and also give the analytical model of the initial stress field.

The authors identified feasibility of the initial stress level of coal-rock masses in steeply inclined coal seams, and revealed that exact acquisition on the displacement of surrounding rock was feasible to analyze the initial stress level of coal-rock masses by the back analytical method in the steeply inclined coal seams as a two-dimensional plane problem.

The calculation results including vertical stress, minimum horizontal principal stress and shearing stress were 7.057, 8.085 and 0.057 MPa, respectively. The KJ743 coal mine initial stress monitoring system was used to collect real-time initial stress data, which were used to check the accuracy of the analytical back results. The value of the vertical stress varied from 6.8 to 7.0 MPa, which is slightly smaller than the result of the back calculation. The minimum principal horizontal stress varied from 7.6 to 8.4 MPa, which is similar to the result of the back calculation.

The purpose of this study is stated regarding the impact of the horizontally polarized shear wave vibration on a composite medium in the terms of phase and damped velocity.

The assumed composite is composed of magneto-elastic fiber-reinforced (MEFR) layer constrained between heterogeneous viscoelastic layer and heterogeneous elastic half-space. The considered heterogeneity is associated with the directional rigidity and mass density in the uppermost layer and half-space of quadratic and trigonometric types, respectively. The coupled field equations related to the respective medium are solved analytically by employing the method of separation of variables.

The dispersion relation of the stated problem is secured by using the continuity assumptions, imposed at the stress-free surface and the interfaces of the expressed medium. The adopted numerical examples are used to compute the dispersion relation and plot the graphs between phase/damped velocity and wave number. Parametric studies on the phase and damped velocity yield five main conclusions: (1) Phase velocity decreases with increasing value of wave number and damped velocity increases up to a certain number and then starts falling simultaneously with increasing magnitude of wave number while keeping the rest parametric values fixed. (2) The presence of heterogeneity in the upper layer enhances the phase velocity and diminishes the damped velocity, but the presence of heterogeneity in the half-space enhances both the phase and damped velocity. (3) The appearance of reinforced parameters enhances the phase velocity for the considered crystalline graphite material and diminishes the phase velocity for the rest materials (carbon fiber-epoxy resin and steel) of the MEFR layer. Similarly, damped velocity decreases for the assumed crystalline graphite material of the MEFR layer and increases for the rest materials of the MEFR layer. (4) The induced dissipation factor due to viscoelastic property shows reversal decreasing and increasing effect on phase and damped velocity of SH-wave. (5) Ascending values of the angle at which the wave crosses the magnetic field increase the phase velocity and decrease the damped velocity for all the considered MEFR examples.

Till date, the mathematical modeling as well as vibrational analysis of wave propagation through the composite structure consisting of MEFR layer constrained between viscoelastic media and elastic half-space under the effect of different varying properties with depth remains a new challenging issue for the researchers around the globe. The current analysis is an approach to move ahead in the era of wave propagation in different realistic models based on their parametric studies. Also, these studies are very helpful to find their applications in the field of mechanical, construction, aerospace, automobile, biomedical, marine, manufacturing industries and many branches of science and technology where magnetic fields induced in elastic deformation occur.

The purpose of this study is to obtain a general solution to the field equations of thermoelastic solid with voids and micro-temperatures under the gravitational field in the context of the three theories, namely, coupled theory (CT), Lord and Shulman theory and Green and Lindsay theory.

The normal mode analysis is used to obtain the exact expressions for the considered variables. Comparisons are made with the results obtained in the three theories with and without gravity. Some particular cases are also deduced from the present investigation.

The effect of the gravity on the displacement, the micro-temperature vector, the temperature distribution, the normal stress, the changes in the volume fraction field and the heat flux moments have been depicted graphically.

Some particular cases are also deduced from the present investigation.

The results of the physical quantities have been illustrated graphically by a comparison between three different theories in the presence and absence of gravity.

This paper seeks to examine the production of wheatless bread from acha flour and to determine consumer acceptability of the product.

Wheatless bread was baked from acha (Digitaria exilis) and Irish potato starch blends of 80:20 respectively with varying (1‐4 per cent) quantity of carboxymethylcellulose (CMC). The loaves were assessed for loaf volume (LV) and specific loaf volume (SLV) as well as consumer acceptability.

The addition of CMC gave an increase in LV of 40.0 per cent in acha bread (AB) with 1 per cent CMC to 59.5 per cent in AB with 4 per cent CMC. The SLV of the acha loaves did not differ significantly from one another. There were significant differences (p < 0.05) between AB without CMC, AB with 1‐3 per cent CMC and wheat bread in appearance, crust colour, crumb texture, crumb colour and general acceptability (p < 0.05). However, there was no significant difference between the AB with 4 per cent CMC and wheat bread in crumb texture, crumb colour and general acceptability. AB with 4 per cent CMC compared favourably with wheat bread in sensory characteristics.

This work was a preliminary work to determine the possibility of producing bread with acha. Further research will investigate the functional and nutritional qualities of AB with 4 per cent CMC found to be comparable with wheat bread.

The study demonstrated the possibility of producing AB using CMC.

Acha has been identified as a major food for diabetic patients in Nigeria by medical practitioners. The AB developed will be of great benefit to countless diabetic patients in Nigeria.