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Justification of the Rheological Model of Process of Plastic Material Injection by the Rollers

Abstract

It is justified thatproblems related to the changes in structural and mechanical properties of plastic material and influence of structural elements of equipment and modes of implementation of the for-mation process on them are considered detail, taking into account empirical data, theoretical dependencies and results of physical experiments. It was established that during the mechanical influence of rollers with grooves on a structured dispersion plastic material in the node of injection of the molding machine, internal shear, and shearing deformation have a preponderant value. Accordingly, the productivity of machines is determined mainly by the structural parameters of the working bodies geometry, kinematics, and contact area. It is shown that increasing the pressure in the plastic material causes a decrease in its volume, but the relationship between pressure and volume has a nonlinear character. It has been established that regardless the variety of flour from which the plastic material was prepared for bagels, its moisture content and the duration of fermentation reduced viscosity of the effective plastic material along with the increase of the shear stress. The paper describes the refined rheological model of the Bingham body deformation, which develops instantaneously, and the velocity of the common elastic deformation in the dough is a simultaneous function of stresses and temperatures, which are close to exponential ones.

Open access
Operation manager and its role in the enterprise

Abstract

Presented paper concentrate on problems connected with the role of operation manager within industrial company. Operation management concentrate many activities in today’s industrial corporation and because of that the role of it’s manager is very important. He should to have many skills described in this paper. We analysed responsibilities of the operation manager, his basic operational skills and also give some examples of duties and responsibilities of good operation manager on the example of food industry. This example can give some remarks about practical skills needed in operation management in particular enterprise.

Open access
Performance Analysis of a Desiccant Evaporative Cooling System for Mango Fruit Storage in the Savannah and Transitional Zones of Ghana

Abstract

Performance analysis of a 1.0 tonne desiccant evaporative cooling storage structure for mango fruits was studied. The study examined the effects of inlet air conditions and water flow rates through an absorber on the cooling performance of the system. The airflow rate was approximately 0.24 m3·s−1 and water flow rates through the absorber varied from 0 to 0.252 l·s−1. The system produced approximately 7 kW of cooling at water supply rate of 0.252 l·s−1. A simple linear correlation was established for condition line slope from inlet to exiting air conditions for all the water flow rates. Lines of best fit resulted in correlation coefficient better than 0.96. The observed temperatures with a direct evaporative cooler, tested with freshly harvested mango fruits were found to be between 15.1°C and 23.4°C and relative humidity between 81.8% and 97.7%. Physiological weight loss and firmness assessments of the fruits were also conducted.

Open access
Present state and future application of smart technologies in manufacturing processes

Abstract

The paper concentrates on the issues of applying smart technologies in the manufacturing processes. The author includes in it brief descriptions of the smart technologies that contributed to the emergence of Industry 4.0 concept. Additionally, based on reports and surveys conducted on a global scale regarding the application of intelligent technologies, the author analyses the current state of implementing these technologies in manufacturing processes and provides forecasts regarding the adoption of the solutions based on Artificial Intelligence in global enterprises in the near future.

Open access
Research on Quality of Maize Grain as a Result of the Application of an Innnovative System for Storing Grain Under Operating Conditions

Abstract

This study analyses the results of research on the improvement of grain quality using a filling core in a grain silo. The research is a part of the research project aimed at developing an innovative system for drying and storing maize grain that, among other benefits, reduces grain damage. Two series were carried out: a control series, in which a chute was applied as the main element, and an operation series, in which a cascade chute was used for testing. The analysis conducted on the simulated operating conditions showed a 4-5-fold reduction in the amount of grain damaged following the application of the filling core compared with the control series. It has also been shown that a 6-meter cascade chute considerably decreases the velocity of the falling grain when loading the silo.

Open access
Safe choice of structural steels in a region of ultra-high number of load cycles

Abstract

In this paper the authors introduce their own selected experimental results in the field of the investigation of fatigue resistance of structural steels. The experiments were carried out on the nine structural steels including high strength steels, DOMEX 700MC, HARDOX 400, HARDOX 450, 100Cr6 (UTS from 446 MPa to 2462 MPa) at high-frequency cyclic loading (f = 20 kHz, T = 20 ± 5 °C, R = -1) in the region of number cycles ranged from N ≈ 2×106 to N ≈ 2×109 cycles of loading. The continuous decrease of fatigue strength in dependence on the number of loading cycles was observed with the average value of ratio σa2×109/σa2×106 = 0.69.

Open access
Stress Analysis of the Sugar Beet Lifter with the Finite Element Method (FEM)

Abstract

The article presents the method of creating a 3D model of a passive lifter with (polder) plowshares, used in sugar beet harvesters, along with stages of its preparation and results of stress analysis. The computer simulation takes into account force timelines obtained during field tests of the tool. The Stress analysis module of the Autodesk Inventor program was used for the analysis, using the finite element method (FEM). The analysis included the elements that constitute the working part of the lifter, whereas elements of the flexible system were omitted. The results confirm that the lifter structure was developed correctly in terms of durability. The highest reduced stresses, calculated according to the Huber-Mises-Hencky (HMH) hypothesis, were 128.4 MPa (the minimum value of the safety factor related to the yield point is 1.61). The paper also discusses the construction of two flexible couplings with infinitely variable torsional stiffness, which can be used as an alternative solution for a typical flexible system: a shock absorber and a helical spring.

Open access
Supply Chain Management in a Production Company

Abstract

The purpose of the supply chain management is to ensure a competitive advantage as well as specific added value for the benefit of all supply chain links. Appropriate management practices generate many benefits, allow for savings in particular segments of the supply chain by means of cost reduction, which in turn directly leads to the competitiveness of enterprises belonging to a specific chain. The above-mentioned issues have become the subject of this thesis. Therefore, the British American Tobacco distribution network is strategically analyzed. A location and number of distribution centers will be i.a. taken into account. Reduction in the number of distribution centers will be suggested in order to reduce logistics costs in the supply chain, i.e. transport and storage. The studies were carried out based on the analysis of flows and route planning of the logistics operator for the transport of the company's products.

Open access
The use of quality management techniques to analyse the cluster of porosities on the turbine outlet nozzle

Abstract

As part of continuous quality improvement in well-managed enterprises, identifying unconformity should initiate actions to find their causes. Therefore, it was proposed to the enterprise located in Podkarpacie to use in the sequential way the Ishikawa diagram and 5Why method. The aim was to analyse of unconformity (porosity cluster) on the turbine outlet nozzle and identify the root of its creation. In the enterprise, the quality analysis of the products with a fluorescent method was carried out, but after identifying the unconformity, non-analysis of their reason for their occurrence was not practiced. Therefore, it was intentional to propose the use of sequence i.e. Ishikawa diagram and 5Why method to identify the root of unconformity. The subject of study was the turbine outlet nozzle, on which the fluorescent method the porosity cluster was identified. With the use of the Ishikawa diagram, the main cause of the problem was pointed (unconformity during production), and by the 5Why method the root cause of the problem, i.e. unconformity material from the supplier, was identified. The proposed method sequence is a simple and effective way to make analyses of unconformities and it can be used in different products and service enterprises.

Open access
Verification of the Peleg and Normand Equation at Varied Loads and Moisture During Stress Relaxation of Wheat

Abstract

Wheat kernel is made up of structures of different apparent viscosities with varied ability to withstand stress and dissipate strain energy. Its complex mechanical behaviour determines technological susceptibility and is important for wheat quality assessment. The aim of the study was the examination of the Peleg and Normand model to characterize the overall stress relaxation behaviour of wheat kernel at varying loading conditions. The relaxation experiments were made with a help of a universal machine Zwick Z020 in compression at four distinct initial load levels, i.e., 20, 30, 40, and 50 N. The measurements were made for intact wheat kernels at seven levels of moisture content. Relaxation characteristics were approximated with the help of Peleg and Normand formula. An interactive influence of the load level and moisture on Peleg and Normand constants have been confirmed. The initial loading level had none or only slight effect on the model coefficients (Y(t), k 1 and k 2). The parameters of the Peleg and Normand model decreased with the increase of water content in kernels. For moist kernels, a higher amount of absorbed compression energy was relaxed, since less energy was necessary to keep the deformation at a constant level.

Open access