DISCOVERY OF NEW KIMBERLITE FIELDS ON THE SOUTHERN SLOPE OF THE LEONE-LIBERIAN SHIELD (Sierra Leone)

During 2017–2018 not far from Sewafeh town, Kono province (Republic of Sierra Leone), we identified a number of previously unknown manifestations of kimberlite magmatism in the form of a system of individual veins localized at the contact of the migmatite basement and Archean ultrabasic massifs, or in the immediate vicinity of ultramafic massifs, which is part of the rocks of the greenstone belt. The optimal sequence of conducting remote sensing studies, such as interpretation of space images of various resolution, neotectonic and geomorphological analysis, SRTM modeling, and then field geological and geophysical research have facilitated this discovery. According to drilling data, kimberlites in different spots of their occurrence (Punduru 1 area) are represented by subvolcanic phlogopite-olivine (with perovskite), and olivine varieties, as well as veins of numerous intensely metasomatic altered kimberlite breccias (Yomby area). Veins of subvolcanic kimberlites are concentrated in the contact part with ultramafic massifs of magmatic and lava (metakomatiite xenoliths) genesis. Kimberlites are the youngest vein formations in the area, crossing even vein pegmatites, the generation of which was provoked by the intrusion of ultramafic rocks in the basement migmatites (Cederholm effect). Kimberlites are present in the section of wells in the form of separate veins of complex morphology and thickness from a few centimeters to 45 cm. In well P1-2 at a depth of 92 m, these are represented by micro porphyry kimberlites of the basaltoid type with microlithic groundmass, altered by secondary metasomatic processes. Porphyry inclusions are represented by pseudomorphs of carbonate-serpentine composition after olivine and rare phlogopite flakes. Olivine crystals of the second-generation act as micro porphyry inclusions. The rock matrix is carbonate. Carbonate is represented by finely crystalline calcite, or replaced by dolomite. In addition to olivine, the groundmass contains relics or pseudomorphs after phlogopite, as well as magnetite, perovskite (it can be replaced by magnetite), secondary apatite. The kimberlites of the Bambawo area are represented by sub-volcanic porphyry basaltoid kimberlites, autolithic kimberlites and kimberlite xenotuff breccias.

Study on detection of lumps in a soft object by using a scanning roller type palpation sensor system

In this study, a palpation sensor system is developed to detect a lump in a soft object. The developed sensor system consists of a contact part using a bearing, two linear sliders and a 3-axis load cell. While the roller type contact part is scanned against a soft object, reaction force applied to the contact part is measured. Lumps are detected by measuring fluctuation of the reaction force. In experiments, the sensor system is scanned against the samples. From the results, it is found that the lump with a small diameter embedded at a deep position.

Research on bolt pre-tightening and relaxation mechanism under transverse load

In order to predict the bolt’s stress distribution under the pre-tightening state and the loosening process under the transverse load, a 3D model considering the bolt thread structure was established by finite element method (FEM). In this study, the looseness effect of transverse load amplitude, the friction coefficient of the bolt head load bearing surface and the thread contact surface are mainly studied. The result indicated that the stress under bolt pre-tightening is mainly concentrated on the contact part of the bolt’s head and bar. At the contact area of the load threads at one end and the transition part between the bolt bar and the thread, the stress and axial direction of the thread part are offset. Under the transverse displacement load, the sliding of the bolt can be divided into three stages: full contact, viscous contact, and full slip. The numerical model of bolt relaxation obtained in this paper can provide reference for the application, checking and prediction of threaded fasteners.

Computational Design Method to Control Touch Feeling of Mattress With Geometric Surface-Shape

Foam material is one of the ingredients that are frequently used for controlling of touch feeling on the contacting part of various products like bed mattresses. For better sleep, it is necessary to design to control the touch feeling of the mattresses. Touch feeling depends on various properties of the foam material, and the shape characteristics of the contact part also give humans various and complicated feelings. According to previous studies, it was possible to easily quantify the physical properties of foam materials by using indentation test. Furthermore, it is necessary to analyze the change in touch feeling due to the shape of contact part of foams for better mattress design. Therefore, in this report, the purpose is to analyze the contact problem including the material property and the shape property of the foam material. A new softness parameter was created by analyzing the contact problem using FEM analysis. Specifically, it is report a design technology based on multiple parameters of tactile sensation that change depending on the shape of the contact part of the foam material.

Generation of Micro Texture Including Calcium and Phosphorus Elements on Titanium Alloy for Improvement of Biocompatibility With Laser Induced Mist Surface Treatment

Titanium alloys are widely used for the hard tissue substitute implants. However, it is necessary to improve interfacial biocompatibility for reduce adhesion period. For improvement of biocompatibility of titanium alloys, texture and chemical composition on contact part with biological tissue play very important roles. In this research, mist of glycerophosphoric acid calcium aqueous solution was applied on the laser irradiated area. As result, micro texture including Ca and P elements was generated on the Ti-6Al-4V-ELI alloys surfaces. When laser was irradiated, glycerophosphoric acid calcium aqueous solution applied as mist flowed on the test pieces as droplet. The velocity of droplet fluid was relatively fast, so that laser irradiation was unhindered access to the surface of specimens and the treatment was stable. In order to estimate biocompatibility of treated surfaces having micro texture with Ca and P element, culture assays using osteoblast cells were conducted. As result, it was clearly that biocompatibility of the specimen treated by laser with glycerophosphoric acid calcium aqueous solution mist more improved than treated specimen soaked in glycerophosphoric acid calcium aqueous solution.

Generation of Biocompatible Titanium Alloy Surfaces Including Calcium and Phosphorus Elements by Laser-Induced Mist Spraying Wet Treatment

Titanium alloys are widely used for the hard tissue substitute implants. However, it is necessary to improve interfacial biocompatibility to reduce adhesion period. For improvement of biocompatibility of Ti-6Al-4V ELI alloys, texture and chemical composition on contact part with biological tissue play very important roles. In this research, micro texture was generated on the Ti-6Al-4V ELI alloy surfaces utilizing laser irradiation, in order to improve biocompatibility. The biocompatibility was evaluated by osteoblast cell culture assays. The results indicated the surface having micro texture improve biocompatibility as compared with untreated surface. This was considered in order the fact that the formed modified surface had hydrophilicity, thereby improving the cell compatibility, and the cell adhesion due to the complicated shape. In addition, mist of glycerophosphoric acid calcium aqueous solution was applied on the laser irradiated area. As result, micro texture including Ca and P elements was generated on the Ti-6Al-4V ELI alloy surfaces. When laser was irradiated, glycerophosphoric acid calcium aqueous solution was applied as mist flowed on the test pieces as droplet. The velocity of droplet fluid was relatively fast, so that laser irradiation was unhindered access to the surface of test pieces and the treatment was stable. In order to estimate biocompatibility, culture assays using osteoblast cells were conducted on the treated surface having micro texture including Ca and P elements. As results, it was clearly that biocompatibility of the specimen treated by laser with glycerophosphoric acid calcium aqueous solution mist more improved than either untreated specimen or treated specimen soaked in glycerophosphoric acid calcium aqueous solution.

Reducing Tyre Hysteresis Losses using CuO Nanoparticles

<p class="5Abstracttext">Tyre is the contact part between the vehicle and road which provides various requirements of performance. Tyres are designed to absorb road irregularities, support vehicle load and provide braking/steering characteristics. An experimental test rig for single tyre test has been designed and constructed to evaluate the tyre performance characteristics under different operating conditions. The tyre load deflection characteristic has been examined by loading and unloading the tested tyre while resting on a hard surface at three inflation pressures. The results showed that the higher hysteresis losses were at tyre inflation pressure 20 psi. Three different percentages of CuO nanoparticles have been used to evaluate their effect on the tyre hysteresis losses. Transmission electron microscopy (TEM) has been performed for the analysis of nanoparticles size. Adding CuO nanoparticle in very small amounts with the enclosed air of the tested tyre can be useful for improving its performance significantly and decreasing the hysteresis losses. This has the potential for making use of the benefits of lower inflation pressure.</p>