Designing a system that removes metallic inclusions from bulk raw materials on the belt conveyor

Modern industrial technologies require raw materials of high purity from suppliers, especially due to the possible presence of inclusions of heterogeneous metals in them. The existence of metallic inclusions of heterogeneous metals in the raw materials leads to equipment failure, a decrease in the quality of output products, and, consequently, large financial losses. Since the main method of transporting raw materials in the industry is still a conveyor belt, this imposes additional conditions to control and remove metallic inclusions. For various reasons, current methods for removing metallic inclusions in the conveyor belt do not fully meet the needs of modern production. The main issue related to existing removal systems is the lack of intelligent interaction between these systems and the absence of information exchange between systems that detect and remove metallic inclusions. An alternative method for removing metallic inclusions of heterogeneous metals from loose medium has been proposed, which implies the tandem operation of the system that detects metallic inclusions and the system that removes them. The tandem operation of the two systems makes it possible to exchange information about a detected metallic inclusion and, as a result, to more flexibly use tools for the removal of metallic inclusion depending on the size and location of the metallic inclusion relative to the conveyor belt axis. At the same time, the control unit of the removal system makes it possible to control the conveyor belt itself, which allows the removal of complex metallic inclusions using the reverse of the electric drive of the belt, as well as enables a control check of the fact of removal. The developed algorithm of the removal system was implemented in the programming environment TIA-Portal. The introduction of this removal system could reduce the number of metallic inclusions in raw materials by 15‒20 %; moreover, its application is not limited to only one sector of the national economy

Performance Assessment of Interaction Soil Pile Structure Using the Fragility Methodology

This study aimed to investigate whether the seismic fragility and performance of interaction soil-pile-structure (ISPS) were affected by different parameters: axial load, a section of the pile, and the longitudinal steel ratio of the pile were implanted in different type of sand (loose, medium, dense). In order to better understand the ISPS phenomena, a series of nonlinear static analysis have been conducted for two different cases, namely: (i) fixed system and (ii) ISPS system, to get the curves of the capacity of every parameter for developing the fragility curve. After a comparison of the numerical results of pushover analysis and fragility curves, the results indicate that these parameters are significantly influenced on lateral capacity, ductility and seismic fragility on the ISPS. The increasing in the axial load exhibit high probabilities of exceeding the damage state. The increase in pile section and longitudinal steel ratio, the effect of probability damage (low and high) are not only related to the propriety geometrically, but also related to the values of ductility and lateral capacity of the system. Doi: 10.28991/cej-2021-03091660 Full Text: PDF

Soil Structure Interaction Effects on R C Structures Subjected to Dynamic Loads

From the past studies, every engineering structure was designed to withstand all external and internal forces applicable to the structure. For this many design methods are implemented and different techniques are found manually, experimentally and practically. One of the parameters which influence the analysis results is, support condition of the structure. Assuming fixed or pinned support in regular analysis of structure considering soil interaction with foundation may not produce accurate results as support condition differ by type of soil ie., loose, medium or hard & their characteristics. So, there is need to study about structural interaction with soil and their outcome deeply. Now a day’s soil structure interaction studies are playing major role in the analysis & design of structures. Many studies are carried out on structure interaction of soil considering seismic or lateral forces. This paper reviews the studies carried out on structural interaction with soil and its impacts on various reinforced concrete buildings subjected to dynamic loads

Effect of randomly distributed polypropylene fiber reinforcement on the shear behavior of sandy soil

The inclusions of geosynthetic materials (fibers, geomembranes and geotextiles) is a new improvement technique that ensures uniformity in the soil during construction. The use of tension resisting discreet inclusions like polypropylene fibers has attracted a significant amount of attention these past years in the improvement of soil performance in a cost-efficient manner. A series of direct shear box tests were conducted on unreinforced and reinforced Chlef sand with different contents of fibers (0, 0.25, 0.5 and0.75%) in order to study the mechanical behavior of sand reinforced with polypropylene fibers. Samples were prepared at three different relative densities 30%, 50% and 80% representing loose, medium dense and dense states,respectively, and performed at normal stresses of 50, 100 and 200 kPa. The experimental results show that the mechanical characteristics are improved with the addition of polypropylene fibers. The inclusion of randomly distributed fibers has a significant effect on the shear strength and dilation of sandy soil. The increase in strength is a function of fiber content, where it has been shown that the mechanical characteristics improve with the increase in fiber content up to 0.75%, this improvement is more significant at a higher normal stress and relative density.

An Experimental Study on the Heat and Mass Transfer of Liquid Nitrogen in a Loose Medium

Liquid nitrogen is a vital medium during the extinguishing and chilldown process of coal spontaneous combustion in coal mine goafs. In this paper, the heat and mass transfer of liquid nitrogen in a loose medium was investigated. A laboratory system including a temperature sensing system was designed and built to explore the effects of different nitrogen injection positions and angles on the chilldown effect. The results indicate that after liquid nitrogen injection, the temperatures in the liquid nitrogen flow area and the bottom of the model can be quickly reduced to −196 °C, which was the best chilldown effect zone. With the vaporization of the liquid nitrogen, the cryogenic nitrogen gradually diffused. At 20,000 s, the bottom temperature was about –63 °C, the middle was –30 °C, and the upper was 0 °C. When the model angle was 0°, the effective chilldown zone was the largest. As the angle increased, the effective chilldown volume and holding time decreased significantly. The model angle had a greater impact on the chilldown. For the position of nitrogen injection, the inlet was set slightly farther from the gas outlet’s position, leading to a larger coverage for the liquid nitrogen and cryogenic nitrogen chilldown. This study can provide a theoretical basis for the flow and chilldown of nitrogen injection in goafs.

Using Dynamic Cone Penetrometer Tester to Determine CBR and Bearing Pressures of Subsurface Soils in Parts of Owerri, Southeastern Nigeria

Using dynamic cone penetrometer tester (DCPT) to determine the CBR and bearing pressure of subsurface soils in parts of Owerri, southeastern Nigeria were investigated in this study. Six (6) DCPT were measured to the depth of 6 m. The data obtained from field DCP test was plotted on the graph of penetration resistance (mm/blow) versus penetration depth (m); which revealed the soil profile of three layers with different penetration consistencies and resistances. The highest PR (mm/blow) recorded was 11.4 mm/blow and the lowest is 55.5 mm/blow. The layers encountered during the measurement ranges from loose, medium and dense soils, where the average thicknesses of loose layers ranges from 0.1 to 0.5 m, medium layers 0.5 to 3.0 m and dense layers 3.0 to 6 m. The average CBR values recorded at interval of 1m to 6 m depths are as follows: 5%, 8%, 12%, 15%, 16% and 16%. Accordingly, the averages bearing pressures calculated were 104.8 KN/m2, 165.5 KN/m2, 231.9 KN/m2, 283.3 KN/m2, 291.5 KN/m2 and 301.1 KN/m2. It shows significant increase in strength with depths.

ANALISIS PLAXIS UNTUK DEWATERING BASEMENT DI TANAH KELEMPUNGAN DAN KEPASIRAN

Galian basement dapat dilakukan dengan beberapa metode disesuaikan dengan kondisi tanah, geometri galian, dan terutama kondisi lapangan, yaitu area tempat dimana akan dilaksanakannya suatu konstruksi bangunan. Salah satu metode yang baik dan akurat untuk digunakan dalam memodelisasikan sifat-sifat tanah yang bervariasi dan material pendukungnya adalah dengan menggunakan metode elemen hingga. PLAXIS 2D merupakan satu dari program-program computer yang dapat menerapkan metode elemen hingga. Penelitian ini dilakukan dengan membandingkan hasil anlisis terhadap kombinasi tanah kelempungan dan kepasiran pada simulasi galian basement dengan program PLAXIS 2D. Analisis dilakukan pada galian yang menggunakan perkuatan secant piles sebagai dinding penahan tanah dan angkur sebagai struktur penunjang. Hasil analisis bertahap terhadap 3 (tiga) kombinasi antara tanah kelempungan (soft, medium, stiff) dan kepasiran (loose, medium, dense) yang dibandingkan dari segi pergeseran dinding dengan nilai terbesar 20,1307 cm , penurunan tanah dengan nilai terbesar 26,75 cm , dan bidang momen yang terbentuk dengan nilai terbesar 146,28 kNm/m.