Browse

1 - 10 of 259 items :

  • Biomaterials and Natural Materials x
  • Transportation, Logistics, Air Traffic, Shipping x
Clear All

Abstract

The paper presents results of experimental studies concerning CO2 emission of S-4003 diesel engine Ursus C-360 at a variable fuel injection advance angle and opening pressure of injectors. Measurements were made on the dynamometric stand on the test bench. The engine operated according to the load characteristic at two characteristic rotational speeds i.e., at the maximum torque velocity (1600 rpm) and at the rated speed (2200 rpm). In each measurement point of load characteristics, CO2 concentration was measured in exhaust gases with the use of exhaust gases analyser M-488 Multigas Plus. For a more detailed analysis of the CO2 content in exhaust gases, additional change of O2 level emission was presented, which in the biggest amount combines elementary carbon included in fuel during combustion. The studies showed the CO2 content reduction in exhaust gases at the reduced (by 3º of crankshaft rotations) fuel injection advance angle in comparison to the nominal angle by 4.5% at the rotational speed of 1600 rpm and by 5.7% at the speed of 2200 rpm (the average values for all measurement points of load - brake horsepower of engine). Similarly, CO2 concentration decrease in exhaust gases of the investigated engine was reported for the increased (by 1.5 MPa) opening pressure of injectors in comparison to the nominal pressure, on average by 9.8% for the speed of the maximum rotational moment and by 4.5% for the rated speed.

Abstract

An evaporative cooling system was designed and constructed to increase the shelf life of stored vegetables. The evaporative cooler was tested and evaluated using freshly harvested roma tomatoes. The equipment operates on the principle of evaporative cooling which increased the relative humidity and decreased temperature in the preservation chamber. The storage system was made up of wood of 25.4 mm thickness. A side of the system is made of jute sack, which was moistened with water flowing through a series of perforated pipes from a reservoir located at the top of the storage system. The water flowed under gravity. The relative humidity and temperature of the tomatoes were analyzed using tinytag humidity, temperature data logger. The weight loss of the tomatoes was also analyzed using a dial gauge scale. The results revealed that there was significant difference in using the evaporative cooling system for storing tomatoes as compared to ambient conditions. The average cooling efficiency was found to be 81%. The average temperature achieved in the cooling system dropped to an average of 23℃ when compared to the average ambient temperature of 33℃, and the relative humidity also increased up to 99% when compared to the average ambient of 59%. The analysis of the evaporative cooling system showed that tomatoes can be stored for more than 6 days with negligible changes in weight, colour and firmness as compared to those under ambient condition, which deteriorated after day 3. The evaporative cooling system was found to be effective and hence can be used by farmers, households, and tomato processing factories for short term storage of fresh tomatoes.

Abstract

The aim of the study was to conduct an economic analysis of the possibilities of using photovoltaic (PV) installations in selected farms. Two selected online PV calculators were used for the analysis. The research included 15 farms located in the Małopolskie Province. For a PV installation estimated using Calculator 1, Hewalex, the payback period ranged from 5.5 to 7 years for the 40% subsidy option and from 9 to 11 years without the subsidy, respectively. On the other hand, the payback period estimated with the use of the SmartekDom calculator ranged from 6 to 8 years for the option with 40% subsidy. However, without the subsidy, the period ranged from 7 to even 13 years.

Abstract

In the aspect of the course and analysis of products of biomass fuels combustion in grill feed boilers, the combustion process of wheat straw and meadow hay were assessed taking into consideration conditions of SO2 emission. Different types of briquettes used in the research not only had various chemical properties but also physical properties. In the aspect of assessment of energy and organic parameters of the combustion process, the sulphur content in biomass becomes a significant factor at its energy use. Registered emission during combustion of meadow hay biomass referred to wheat biomass was for A and B type briquettes correspondingly higher by ca. 320 and 120%. Differences in SO2 emission at combustion of various biofuel forms in the aspect of the relation with the remaining combustion parameters including mainly with air flow require, however, further research that leads to development of low-emission and high-efficient biofuel combustion technologies in low-power heating devices.

Abstract

Many factors influence milk production and farm development. The most critical factor determining the production is the price of sold milk and indirectly the costs connected with its production. In majority of farms, milk production is profitable. The decisive factors influencing the profitability of milk production are the balance of nutrition and ensuring the welfare of dairy herds. Equally important are the genetic characteristics of cows and proper rearing of calves. The study shows that the modernization of farms also influences the development of milk production by improving the optimization of energy use and reducing labour intensity, and overall optimization of production costs.

Abstract

The article presents determination methods of characteristic values of the reaction force course during the impact on fruit and vegetables to quickly assess their firmness or maturity. Moreover, various methods of modelling of the plant material behaviour during the impact that use differential equations, analytical equations, statistic models and numerical methods were discussed. Furthermore, dynamic methods that use fruit dropping on a rigid plate and measurement techniques that use a rigid element that hits a motionless fruit were reviewed and assessed. Advantages and disadvantages of these methods were presented. Statistical models are better for assessment of the bruise damage, but theoretical models are more useful for understanding the impact of various factors related to the impact damage. Various methods of application of rheological theories that describe a behaviour of the produce tissue treated as an elastic, elastic and plastic and visco-elastic were also described.

Abstract

The first part of the article contains a basic description of the mushroom production process. The analysis of this process allows to propose algorithms for monitoring the growing conditions and controlling the cultivation process − in the latter case with possible human operator intervention. These algorithms, along with their description, are included in the second part of the article - they can be used in the design and implementation of intelligent mushroom farm management systems.

Abstract

In 2020, a fully automated hydropower plant was launched on the Guber River near the town of Kotkowo. The plant is operated by a master control and measurement system, which collects data to evaluate the operation of selected systems of the facility. The number and location of sensors controlling the parameters of hydroelectric systems are selected accordingly, to collect complete information from all sensors and analyze the operation of hydroelectric systems in real time. In addition, storing all the controlled parameters allows analyzing the plant’s operation over longer periods. This work presents the possibilities of this measurement system, as well as the measurement results obtained in the tested object. Analyzing the operation of the control and measurement system as well as the collected and archived data will be the foundation for a simulation model of a hydropower plant. The model will be helpful in optimizing the operation of existing hydroelectric plants in terms of energy production per unit volume of water, and in designing new ones on existing barrage.

Abstract

Excessive distribution of holdings is one of the most important barriers which causes that in a great part of Poland rational use of farms in impossible. This problem particularly concerns the south and east region of the country. Correct spatial distribution of lands belonging to holdings is one of the most crucial factors that enable an economically profitable activity of these farms. The aim of the paper was verification of the applicability of the prepared spatial data base, farm-land configuration of agricultural plots of the selected agricultural farms to indicate the areas of optimization of the internal transport. As a result, based on the developed spatial data base, an impact of the land configuration of agricultural plots in the investigated group of agricultural producers on organization of the field transport between the holding and agricultural plots was determined. The scope of the paper covered a vegetable producer group, which associates 5 farms that have in total 620 ha of agricultural land.