Results 1 - 10 of 11299
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[en] The article presents the results of experimental studies on the grinding process of a clinker preliminarily ground in press roller mills in a ball mill equipped with energy exchange devices. The authors studied the influence of the coefficients of loading for grinding bodies of the first and second mill chambers, their lengths, angles of inclination, and the mutual location of energy exchange devices (the ellipse segment and the double-acting blade) on the output parameters of the grinding process (productivity, drive power consumption and specific energy consumption). It is clarified that the best results of the disaggregation and grinding process, judging by the minimum specific energy consumption in the grinding of clinker with an anisotropic texture after force deformation between the rolls of a press roller shredder, are achieved at a certain angle of ellipse segment inclination; the length of the first chamber and the coefficients of loading the chambers with grinding bodies. (paper)
[en] Highlights: • We propose an original mixed integer programming formulation to optimize mine haulage equipment scheduling in the long term. • The model considers the effects of equipment aging, fuel consumption, payload capacity and cycle times. • The model considers joint minimization of fuel, M&R, and overhaul costs. • The case study shows a cost reduction of 13% in the discounted flows associated with total costs in a time horizon of 10 years. Different complexities force mining companies to find efficient ways to respond to demand challenges and ensure long-term sustainability. It explains, in part, the increase in the use of prescriptive analytics to optimize physical-asset life-cycle costs and decrease greenhouse gas (GHG) emissions. Mining, being an asset-intensive industry, provides huge improvement opportunities. This is especially true for scheduling practices of mine haulage fleet usage in long term planning. Fleet aging implies important cost increases in maintenance and repair (M&R), and overhauls. Fleets are often heterogeneous in term of truck performance, fuel consumption and GHG emissions. Sub-optimal scheduling decisions may induce severe cost over-runs and increased emissions. This paper proposes an original mixed integer programming formulation to optimize mine haulage equipment scheduling in the long term. The model considers the effects of equipment aging, fuel consumption, payload capacity and cycle times. Our formulation handles different aspects that according to author’s knowledge have not been considered in the literature as a whole: (i) joint minimization of fuel, M&R, and overhaul costs, (ii) reduction of GHG emissions, (iii) heterogeneous equipment performance metrics, (iv) increase in cycle times due to mine aging. The case study shows a cost reduction of 13% in the discounted flows associated with fuel, M&R, and overhauls in a time horizon of 10 years. This figure translates into an NPV gain of 13.1 million USD. Additionally, GHG emissions are reduced by an average of 3470 t/year or 11% overall.
[en] Loading-unloading system is one of the major systems of the SVST-Co60/B irradiator. However, this system has been operating by hand, it takes a lot of time and health of workers leads to labor-productivity is low. This project aims to design and manufacture a tote box loading system which works fully automatic and an unloading system works by manual of the SVST-Co60/B irradiator in order to reduce physical labor at the loading-unloading area. (author)
[en] Human osteoarthritic chondrocytes (hOACs) are characterized by their “dedifferentiated” and catabolic phenotype and lack the ability for restoring their inherent functions by themselves. Here we investigated whether extrinsically supplemented mechanical signal via compression loading would affect the phenotype of hOACs. Specifically, we applied cyclic compression loading on cultured hOACs-collagen constructs and measured the expression of the major chondrogenic factors, cell-matrix interaction molecules and matrix degradation enzymes. Dynamic compression loading stimulates the expression and nuclear localization of sox9 in hOACs and reduces the catabolic events via downregulated expression of collagenases. These results contribute to better understanding towards mechanoregulation of hOACs.
[en] The article proposes technical solutions for increasing the efficiency of finishing-cleaning and hardening processing of parts on the basis of rotor-screw technological systems. The essence, design features and technological capabilities of the rotor-screw technological system with a rotating container are disclosed, which allows one to expand the range of the resulting displacement vectors, granules of the abrasive medium and processed parts. Ways of intensification of the processing on their basis by means of vibration activation of the process providing a combined effect on the mass of loading of large and small amplitude low-frequency oscillations are proposed. The results of the experimental studies of the movement of bulk materials in a screw container are presented, which showed that Kv = 0.5-0.6 can be considered the optimal value of the container filling factor. The estimation of screw containers application efficiency proceeding from their design features is given. (paper)
[en] It has been experimentally established that the possibility of multi-contact shock systems can transmit large total energy of the impact pulse to the deformation center. Thus, an increase in the number of instruments in a shock system from two to four, with the constant energy of the shock pulse, made it possible to increase the depth and the degree of hardening in the surface layer. The performance of multi-contact impact systems can be increased by 50% without degrading the hardening parameters by increasing the distance between the tools. (paper)
[en] According to the flux mapping data, some of domestic WH type plants have experienced AOA (Axial Offset Anomaly) in several years. AOA is a phenomenon that the axial power distribution is considerably shifted to the bottom of the core compared with the predicted one. The root-cause is known as the deposition of boron compound (LiBO2) in the crud that is accumulated in the upper portion of a fuel assembly. At first, by analyzing flux mapping data, we have modeled AOA experienced cycle by 3D depletion code and determined approximately the boron mass deposited in crud. AOA model can be used to evaluate the effects of AOA. In addition, we need to setup a procedure to assess loading patterns for AOA risk and to give recommendations to the operators, if necessary. As a part of Loading Pattern Risk Assessment, we constructed the AOA prediction system to evaluate whether the selected loading pattern has the higher AOA risk or not. This procedure is described herein and application results are presented
[en] We demonstrate the recently developed technique of laser driven isentropic compression (ICE) for dynamically compressing Al samples at high loading rates close to the room temperature isentrope and up to peak stresses above 100GPa. Upon analysis of the unloading profiles from a multi-stepped Al/LiF target a continuous path through Stress-Density space may be calculated. For materials with phase transformations ramp compression techniques reveals the location of equilibrium phase boundaries and provide information on the kinetics of the lattice re-ordering