ANALISIS POSTUR KERJA PADA BAGIAN GUDANG MUAT GREY DI PT SURYA PUTRA MULIA

PT Surya Putra Mulia is a company that produces gray (greige) using the knitting process. This research is focused on the warehouse section on the loading process finished goods. In the warehouse section there are some excessive physical activities due to activities are carried out manually. Measurement of work posture is needed to determine whether the work posture carried out by the operator is good and ergonomic. Assessment of work posture is carried out using the Rapid Entire Body Assessment (REBA) method. Based on an assessment using the REBA (Rapid Entire Body Assessment) method, it shows that the withdrawal of finished goods includes a moderate level of risk, which means that improvements are needed. The activity of loading finished goods onto trucks (figure 3) includes a moderate risk level which means that repairs are needed, while in Figure 4 it is a high risk level which means that immediate corrective action is needed. For the preparation of finished goods on trucks, it is a moderate risk level, which means that repairs are needed. So that in the process of withdrawing finished goods, proposals are given to reduce the burden being transported. Then add a tool in the process of loading finished goods to the truck in the form of a hand stacker.

Design of a Controlled-Release Delivery Composite of Antibacterial Agent Gatifloxacin by Spherical Silica Nanocarrier

In this study, a spherical silica nanoparticle was explored as a gatifloxacin carrier synthesized by the chemical precipitation method. It was found that there was no new chemical bond formation during the loading process between gatifloxacin and silica, which implies that the binding was driven by physical interaction. In addition, the drug loading and encapsulation efficiency could be improved by appropriately increasing nano-silica content in the loading process. Meanwhile, the release rate of gatifloxacin after loading nano-silica was also improved, suggesting the successful design of a controlled-release delivery composite. The silica nanocarrier could significantly improve the antibacterial performance of Escherichia coli by 2.1 times, which was higher than the pure gatifloxacin. The 24 h bacteriostatic rate was higher than that of a simple mixture of silica nanoparticles and gatifloxacin. Strong reactive oxygen species (ROS) in GAT-SiO2 NPs suggests that ROS might be associated with bactericidal activity. The synergy between the physicochemical effect and ROS production of this material is proposed as the mechanism of its antibacterial activity, which can also be confirmed by the cell membrane damage observed under electron microscopy and DNA damage experiments. Collectively, our finding indicates that nano-silica microspheres could serve as a promising carrier for the sustained release of gatifloxacin, thereby providing a new carrier design scheme for the improvement of the antibacterial effect.

Calculation features of compressed-bent build-up timber columns with nonlinear-deformable shear bracings

Object of research is build-up compressed–bent and eccentrically compressed columns on yielding nonlinear – deformable shear bracings. Purpose of the research is development of a numerical method for calculation of columns, allowing to take in account the influence of deflection of elastic axis of bar on the increment of the bending moment from the action of longitudinal compressive force and the nonlinear dependence between the forces and deformations in the shear bracings. Problem-solving method consists in dividing the column into separate sections, a system of equations is compiled from the condition of equality of the increment of concentrated shears. The loading process is divided into a set number of stages, at each forces in the shear bracings, the stresses in the branches, and the buckling function of the elastic axis of the element are determined. The obtained values of forces in the shear bracings and buckling are used to specify stiffness of the bracings and component of the bending moment arising due to eccentric application of the longitudinal compressive force when longitudinal axis of the element is deflecting. To obtain the resulting values, the obtained forces, deflections and stresses in the branches at each calculation stage are summed up.

An approach to optimize container locations in a containership with Electre III

In this article, we treat the problem of container storage in the export direction, exactly in the containership loading process. We propose an approach to the problem of container placement in a containership by describing a decision model to help decision-makers (handling operators) to minimize the total containers shifting. This is obtained by using a multicriteria decision method named Electre III (Elimination and Choice Expressing Reality) to identify the best location of any container. Here, we consider four criteria: the container destination, the container weight, the departure date of the container and the container type. This method has as input a matrix of performance and the subjective parameters and gives a ranking of alternatives as an output.

The Effect of Changing Stirrup Spacing and Hook Angle on RC Cantilever Beams with Industrial Iron Chips Waste

In this study, the usability of industrial iron chips waste was investigated in order to provide recycling in the production of reinforced concrete cantilever beams with different stirrup spacing and hook angle. In the concrete produced for cantilever beams, aggregates not larger than 4 mm in diameter were reduced by 20% and replaced with iron chips waste. Cantilever beams are manufactured with stirrup spaces of 50, 100 and 150 mm. The hook angles of the stirrups are differentiated to be 90 and 135 degrees. The experimental setup was prepared in such a way that one side of the samples was fixed, and the other side was free. The loading process was done from the end point of the released side. Load-Displacement curves of cantilever beams were obtained. In the research, it was observed that although 20% iron chips added cantilever beams experienced a decrease in their strength compared to the reference beams, they increased their ductility values at all three different stirrup spaces. As the stirrup spacing widened, the ductility values decreased. However, the effect of iron chips additive on ductility has increased. Samples with stirrup hook angle of 135 degrees increased both strength and ductility values compared to samples with 90 degrees.

Application of an improved mining complex for opencast mining of ore deposits

The purpose of the study is reducing the loss of mineral raw materials and increasing the efficiency of mining operations using a mining complex through the introduction of a new design and engineering solution that improves the equipment functionality. The study involves the analysis of known designs of mining equipment capable of providing the transformation of cyclic scooping of rock mass into its continuous loading, as well as screening of fine fractions from the ore mass. High productivity mining complexes are referred to a promising direction of mining equipment development. The article proposes an improved design of the mining complex, which allows to combine the extraction and loading process and ore mass grading. The improved mining complex is equipped with an annular conveyor with vibrating grids through which fines are screened into the accumulation hopper. From the accumulation hopper the small fractions are sent by means of a pneumatic conveying system to the bunker sections of a special-purpose hauler while the oversize product is loaded into a dump truck by a dump conveyor. The fine fractions of substandard ore collected in the bunker sections are sent for heap leaching. The fine fractions of conditioned ore are sent to the concentration plant to be processed. The proposed design and engineering solution employing an improved mining complex will reduce the cost of works and increase the recovery factor of mineral raw materials in the development of complex-structured deposits of ores characterized by natural concentration of small classes. Removal of fine ore fractions directly during the excavation and loading process can significantly reduce the dusting and decrease the loss of mineral raw materials from blowing and spilling of fine fractions.

Evaluation of the threshold for the development of fatigue cracks in a railway steel under harmonic and operational loading

The results of experimental studies of the fatigue crack development in 20GFL steel specimens cut from a cast bolster of a freight car are presented. The ratio of the threshold stress intensity coefficient Kth determined from the kinetic diagram of fatigue fracture and from the average parameters of the operational loading process is considered using the experimental results with a simulation of operational loading. Tests were carried out upon the development of permanent blocks of crack opening in the specimen (in a rigid loading mode). The operational process is presented in the form of a block of consecutive loading cycles recorded during the test of the car frame in conditions typical for a straight section of the railway track. The threshold operational level is determined by the algorithm of gradual reduction of the loading similar to the original process. The regularities in a decrease of the rate of crack development and corresponding decrease in the load were determined. Subsequent extrapolation of the obtained experimental regularities to zero value of the crack propagation rate provided estimation of the threshold loading level, similar to the initially specified value. It is shown that the value of the threshold level of the fatigue crack development in low-alloy steel 20GFL obtained from the fatigue fracture diagram (i.e., under harmonic loading) is significantly higher than that obtained from the estimate based on the average values of the operational loading process. The considered model of operational loading gives greater damage compared to harmonic loading, on the basis of which the survivability of structural elements is usually assessed.

Research on Shear Behavior of Sand–Structure Interface Based on Monotonic and Cyclic Tests

In order to study the shear behavior of the interface between sand and structure, a series of shear tests were carried out using an HJ-1 ring shear apparatus (Nanjing, China). First, through the monotonic shear tests, the loose sand and dense sand were sheared at the steel interface with different roughnesses. The results showed that when the interface was relatively smooth, the shear stress–shear displacement curves of loose sand and dense sand both exhibit strain hardening characteristics. When the interface was rough, the dense sand showed strain softening. The initial shear stiffness of the sand–steel interface increased with the increase in normal stress, interface roughness, or sand relative density. Then, considering the influence of initial shear stress, through the cyclic shear test, this work analyzed the shape of the loading and unloading curves and the development law of cumulative normal deformation, and discussed the change of loading and unloading shear stiffness under different stress level amplitudes and the residual deformation generated during the cycle. The research results showed that loose sand and dense sand generally shrunk in volume during the cycle. The initial loading process was similar to the case of static loading. In the later dynamic loading process, the shear shrinkage per cycle was relatively small and continued to develop. Additionally, it was found that the unloading stiffness of the sand–steel interface is always greater than the initial loading stiffness. As the number of cycles increases, the loading stiffness increases, and it may eventually approach the unloading stiffness.

Development of auto loading device in bearing positioning lip stamping

With the continuous development of our economy, the types and quantity of engine bearing are increasing. In order to prevent the bearing moving in the bearing pedestal, one or both ends of the bearing need to make positioning lip for axial positioning. In order to meet the needs of mass bearing production, an auto loading device for positioning lip of bearing is proposed in this paper. The horizontal conveyor belt and loading guide are used to make the blank turn to the required angle, and then the double cylinder valve and push rod motor are used to realize the time-sharing conveying and continuous loading of the blank. During the loading process, there are inclined slideway and blocking plate to avoid the collision between blanks and ensure the reliable loading bearings. Through the actual production verification, the developed device has the advantages of simple structure, low cost, fine working stability, and made great improving in the efficiency and safety for production of bearing.