Freight Fleet Management Problem: Evaluation of a Truck Utilization Rate Based on Agent Modeling

The article deals with the problem of estimating the rational number and utilization rate of the vehicles' fleet. According to the analysis results of the state-of-the-art literature it has been revealed that the issue of substantiating the rational fleet size and the rate of its utilization were not fully solved. The purpose of the study was to increase the efficiency of servicing transportation orders by determining the required number of vehicles. The goal of the research was the influence of the transportation process parameters on the truck utilization rate. Originating from the probabilistic nature of the transportation process, it has been proposed to use the AnyLogic software product to develop a simulation model for vehicle orders' servicing. From the processing of the experimental results by the regression analysis methods, it has been found that the dependence of changes in the vehicle utilization rate is of a linear form.

Study on preparation process parameters and tribological properties of porous PI materials

Purpose Previously, the effect of pore-forming agents on the properties of pore size and morphology was studied. In this paper, we determine the optimal combination of parameters by tensile strength and perform tribological tests with optimal combination of parameters. Design/methodology/approach In this paper, porous polyimide (PI) materials were fabricated using vacuum hot molding technology. The orthogonal experiment was designed to test the mechanical properties of porous PI materials with the process parameters and the content of pore-forming agent as the changing factors. The porous PI oil-bearing materials were obtained by vacuum immersion, and tribological test were carried out. Findings The results showed that porous PI oil-bearing materials are suitable for low-speed and low-load conditions. The actual value of the friction coefficient basically match with the theoretical value of the regression analysis, and the errors of the friction coefficient are within 10% and 3%, respectively, which proves that the method used in the study is feasible for the friction coefficient prediction. Originality/value In this paper, we have produced a new porous oil-bearing material with good tribological properties. This study can effectively predict the friction coefficient of PI porous material.

Optimization study on wet electrostatic powder coating process to manufacture UHMWPE/LDPE towpregs

In the present study, an attempt has been made to coat the non-conductive Ultra-high Molecular Weight Polyethylene (UHMWPE) fibers with Low-Density Polyethylene (LDPE) powder. In order to enable the deposition of electrostatically charged LDPE powder onto the fiber surface, UHMWPE fibers are dipped into a surface modification bath to impart momentary conductivity. Further, Box Behnken’s experimental design is used to optimize the processing parameters for Fiber Volume Fraction (Vf) for this wet electrostatic spray coating process. An experimental multi-parametric equation is acquired through response surface methodology to ascertain the association amid the process parameters such as processing temperature (A), conveying air pressure (B), and gun nozzle angle (C) on the output response of Vf. The process parametric values for A, B, and C are varied from 225°C to 245°C, 0.2 bar to 0.4 bar, and 0° to 120° respectively. The Vf obtained is in the range of 37.02%–56.28% depending on the combination of process parametric values. Powder pick-up increases with an increase in the gun nozzle angle. An increase in conveying air pressure and temperature of the hot air oven leads to an increase in powder deposition. The values predicted from the model are observed to be in close proximity (94.59%) to the experimental results. Gun nozzle angle is the principal parameter affecting the matrix deposition on the fiber surface in comparison to other process parameters.