Browse

1 - 10 of 338 items :

  • Mechanical Engineering x
  • Business Management x
  • Materials Sciences x
  • Engineering x
Clear All

Abstract

The paper analyzes the costs of production of wood sawdust briquettes, manufactured by the company Brykiet-Pol2, based in Goleszów in southern Poland. In addition, production technology, raw material supply and distribution of the finished product were analyzed. The costs of producing one ton of briquettes for the four assessed variants ranged from PLN 364.8 (option D) to PLN 648.7 (option A). The cost structure was dominated by the purchase of raw material and depreciation of the technological line. The most economically advantageous production variant was option C, currently implemented in the company (production costs: PLN 458.7·t−1), and the proposed option D, using two briquetting presses. The latter option increased production efficiency and reduced unit costs of briquette production in a three-shift system around the clock.

Abstract

The article presents an analysis of the energy, mechanical and chemical properties of pellets made of wood material. According to the manufacturer, wood pellets were made of hard wood shredded to fractions approx. 1 mm thick and up to 3-4 mm long, and of a waste source - sawdust. Measurements of the selected properties were carried out on pellets with a diameter of 6 and 8 mm. Mechanical durability, humidity, crumble rate, ash quantity, calorific value were determined, as well as macronutrient and heavy metals content. The calorific value of pellets, with moisture content from 7.48% to 6.76% and ash content from 0.31% to 0.55%, ranged from 17.71-19.18 MJ·kg−1, which testified to the beneficial energy use of the tested raw material. Based on the conducted research, it was found that the mechanical properties of pellets made of both sawdust and hard wood predispose them for use as boiler fuel. The tested materials met high quality standards for wood pellets used for non-industrial and industrial purposes.

Abstract

Field tests on the quality of shaking off redcurrant fruit Rosetta cultivar with a half-row trailer harvester “Marek” produced by Dom-Wid were carried out. The tests were performed at two average working speeds ῡ1 = 0.47 m·s−1; ῡ2 = 0.60 m·s−1 and two rotational speeds of a tractor n1 = 1500 rpm; n2 = 1900 rpm. The length and diameter of shoots of redcurrant, length of a bunch, number of fruits in a bunch and mass of fruit were measured. Weather conditions were presented: rain fall, air temperature and moisture. Analysis of results showed that the working speed and the rotational speed has a significant impact on the quality and amount of the yield. At the highest rotations, the harvesting quality of fruit by a harvester was the worst and was 77.15%.

Abstract

Designing and proper implementation of effective processes and providing the customer with high quality products undoubtedly determines the stable position on the market. The aim of the study was to analyse the cost and value of the technological process of doors in the context of creating added value and to identify unnecessary processes (not creating added value) in relation to which appropriate corrective actions could contribute to their elimination. Thanks to the application of remedial measures, consistent with the lean manufacturing concept, the study eliminated, among other things, operations related to unnecessary transport and storage of products, which resulted in both the reduction of time and costs of process implementation.

Abstract

The research material was prune plums (Prunus domestica L.), subjected to osmotic pre-treatment, with variable process time parameters and osmotic solution concentration. Plums thus fixed were frozen and stored for 6 months. At even (monthly) intervals, the product was defrosted by the vacuum-steam method, using the s-p-p chamber, until the thermocouple indicated a temperature of 4ºC in the sample’s thermal center. In order to study the kinetics of phenomena occurring during the defrosting process, the chamber was equipped with a measuring system to enable measurement and recording of temperature changes in time in the geometric center of the sample, as well as the temperature on the sample surface. The conducted tests proved that the time of vacuum-steam defrosting of fruit depended on the amount of water contained in it. In plums dehydrated in 45-65% sucrose solutions, duration of the defrosting process was shortened already after three months of frozen storage. After 6 months of storage, defrosting of these fruits was twice as fast as that of control samples.

Abstract

Development of innovative technological solutions in animal production should be associated with reduction of greenhouse gases, ammonia emission, and with rational disposal of natural fertilizers. The presented solutions and concepts of biogas acquisition and its disposal as well as a disposal of digestate mass place a need to improve the technological process before the science. The main aim of the presented solutions for the use of methane fermentation of a natural fertiliser in agricultural conditions is their utilization and energy acquisition, in particular for households and farms. When considering the issue of methane fermentation, one should include all favourable fertilization, energy aspects and firstly, the ecological ones. During the methane fermentation, substrates are stabilized due to removal of a large amount of carbon. The only elements that are removed from the system are evolving gases: CH4, CO2 and H2S. During the discussed process, the entire nitrogen is preserved in the organic or ammonia form.

Abstract

A modern model of agriculture is based on three orders - organic, social and economic. An attempt was made in this paper to apply cluster analysis for assessment of economic and organic sustainability of organic farms. Factors that statistically influenced a decision on which farms should be recognised as sustainable were indicated. Analyses allow the following conclusion: 1) in organic farming, animal production including cattle breeding and rearing must be based on a high acreage of permanent grasslands; 2) neither the performed production processes nor the level of their automation rate or the level of organic balance do not decide on the production effectiveness, but factors of the surrounding including social factors.

Abstract

Making a complex analysis of the problem in order to identify the root of its occurrence, is the process burdened with the risk of uncertainty. This risk is in case of the quality analysis, in which the choice and making a decision is not confirmed by reliable information (number). This risk is in case of the quality analysis, in which the choice and making a decision is not confirmed by reliable information (number). But these techniques do not include the risk of uncertainty, so their sequence should be expanded about the appropriate method, to take this into account. It was considered beneficial to demonstrate that this method is the Fuzzy Analytic Hierarchy Process method (FAHP). The aim of the study to implement the FAHP method in the sequence of traditional quality management techniques (Ishikawa diagram and 5Why method) and proposition new, not practiced yet the method to complex analysis of the problem and identify the root of its root cause. The subject of the study was the furniture front, on which the incompatibility was identified (shortened foil). From the categories to which the potential causes of the inadequate foil were assigned, by using the Ishikawa diagram and the FAHP method in an integrated manner, were defined the most important categories (method and machine) in a precise (numerical) way. Next, using the same tools, the relationship between the potential causes was analysed and selected the main causes of the problem. Then, by using the 5Why method the root of the problem was defined (lack of the new machine and failure to comply with labor standards). The obtained results could differ depending on the subjectivity, however, the method itself proved to be effective and can be used to solve other types of the problem.

Abstract

The aim of the experiment was to determine the impact of UV-C stimulation of tubers, immersion of potato sticks in water, and a frying fat type on the content of fat in dry mass of French fries. Tests were carried out on Innovator tubers which is one of the most often used cultivator in production of French fries by the European and Polish companies. Radiation of potato tubers with ultraviolet in band C were performed with the use of the original stand for stimulation of biological material with electro-magnetic radiation. A statistical analysis of the obtained results of tests indicates that stimulation of tubers and a type of frying fat had a statistically significant impact on the fat content in dry mass of French fries.

Abstract

The use of cast aluminium has still increased, so have the mechanical property requirements. By casting and also in other metallurgical processes, the inclusions enter to the molten aluminium alloy and it exhibits poor ductility or toughness. It can cause a variety of problems in the manufacture of aluminium alloy castings. Therefore, the purification of the molten aluminium alloy is one of the most important processes for improving the quality of Al-products. Filters have been used for many years in order to improve the quality of castings. The inclusions in molten secondary AlSi7Mg0.3 cast were removed using depth filtration by ceramic foam filters of 20 ppi porosity. Were used 4 types of ceramic filters in 2 thicknesses (15 and 22 mm); Brinell hardness and porosity were measured. Quality of microstructure (occurrence of oxidic particles and larger non-metallic inclusions) was observed. Experimental results show that the insertion of ceramic filters into the inlet system has contributed primarily to a decrease in porosity. On the microstructure, the inclusion of filters was not significantly reflected.