For new railway bridges with small spans (L ≤ 35.00 m) superstructures with steel beams embedded in concrete are recommended and used, which can ensure the requirements of strength and especially stiffness, regardless of velocity.
In all the design prescriptions used so far for superstructures with steel beams embedded in concrete, and even in the technical literature, there is little information and data on the influence of the support line obliquity and the track axis curvature in the design and calculation of these types of structures.
In the design code, if certain conditions related to the geometry of the superstructure are met (obliquity, curvature) the calculation is a simplified one, made on a single isolated longitudinal beam of the deck; otherwise, if the conditions are not met, finite element program analysis is recommended.
The article aims to study the situations in which the requirements of the design prescriptions are not met.
Traian Mazilu, Ionuţ Radu Răcănel and George Stoicescu
The rail dampers are mechanical devices which work as dynamic absorbers to reduce the rail vibration and rolling noise. The paper shows the experimental results from the functionality and performance testing of an experimental demonstrative rail damper. The vibration attenuation takes the highest values, namely 6-22 dB, between 160 and 1000 Hz.
The aim of this study was to develop discrimination models based on textural features for the identification of barley kernels infected with fungi of the genus Fusarium and healthy kernels. Infected barley kernels with altered shape and discoloration and healthy barley kernels were scanned. Textures were computed using MaZda software. The kernels were classified as infected and healthy with the use of the WEKA application. In the case of RGB, Lab and XYZ color models, the classification accuracies based on 10 selected textures with the highest discriminative power ranged from 95 to 100%. The lowest result (95%) was noted in XYZ color model and Multi Class Classifier for the textures selected using the Ranker method and the OneR attribute evaluator. Selected classifiers were characterized by 100% accuracy in the case of all color models and selection methods. The highest number of 100% results was obtained for the Lab color model with Naive Bayes, LDA, IBk, Multi Class Classifier and J48 classifiers in the Best First selection method with the CFS subset evaluator.
Contemporary agricultural engineering searches for “safe” methods of raising crop yields, using a combination of knowledge from a number of sciences. Thus, computer modelling of plant growth and development fits this range, because it has become an area of interdisciplinary research. Presentation of knowledge in the form of mathematical computer models is one of paradigms of agricultural production systems based on the scientific and practical knowledge and information. In the scientific activity concerning agricultural engineering research tasks related to mathematical modelling of agrobiological processes have been carried out for many years. Additionally, the use of modern forecasting techniques in agriculture may bring real financial advantages with regard to the fact that based on crop yield prediction estimation of their cultivation profitability is possible. Dynamic and continuous progress of computer and informative technologies creates new opportunities showing thus growth directions of agricultural engineering. Taking this into consideration, it should be emphasised that mathematical modelling constitutes a support for decision processes which take place in agricultural production. This article discusses mathematical models, where the analysed system is described with the use of mathematical formulas. The objective of the paper was to present the current state of knowledge on mathematical methods in describing and predicting seeds germination. Possibilities of their use and new challenges which occur in the description of seeds germination were presented.
Interdisciplinary nature of scientific research with regard to agriculture caused a development of mathematical modelling with regard to plant growth and development. Application of mathematical sciences in agriculture suits well the area of agricultural engineering which covers the issues related to inter alia, application of mathematical sciences. This article presents mathematical models, in which the analysed system is described with mathematical formulas. The objective of the paper was to present the current state of knowledge on mathematical methods in description and prediction of plant germination. Possibilities of the use of mathematical models and new challenges occurring in the description of plant germination were presented.
The objective of the paper was to analyse the expenditures of labour in production of three selected fruit types (apples, black currant and gooseberry) including, inter alia, in relation to the surface area of a plantation. The total inputs of labour were calculated with a division into manual and mechanized works. Moreover, a detailed structure of manual and mechanized works was presented. It was stated, inter alia, that labour consumption of apple production is approximately four times higher in comparison to black currant and gooseberry. No impact of the plantation size on the total work inputs on fruit production was reported.
The aim of the paper is to discuss the links between modern livestock production, including its techniques and concentration, with animal welfare requirements. Modern livestock production is related to modern facilities, precise livestock production, as well as intensive and high stocking density. At the same time, it requires providing the animals with minimal living conditions, i.e. the welfare set out in the relevant regulations. This in turn should guarantee a good quality of raw livestock materials and products.
Kinga Śnieg, Dariusz Błażejczak and Małgorzata Słowik
The objective of the research was to construct an empirical model for prediction of a unit pressure indispensable for generation of a specific compaction of soil samples. Soil material in the form of loose mass was collected from the soil layer deposited in the depth from 35 to 40 cm and then its typical properties were determined (textural group, density of solid particles, humus content, reaction, plastic and liquid limits) and in order to compact it in Proctor apparatus and in the uniaxial compression test. Results of both tests were used for construction of regression models reflecting the course of the unit strength (Pρd) necessary to generate compaction (ρdj) equal to the dry bulk density obtained in Proctor apparatus (ρdp), in relation to the sample moisture (ρdm). Searching for relations was restricted to the scope of moisure between an optimal one acc. to Proctor and the soil plastic limit. It was stated that the pressure value Pρdp made on the soil sample in the uniaxial compression test depends significantly on ws and ρdm, and for description of this relation the use of multiple regression is sufficient. It was found out that for model samples with a textural group of silt loam and loam, differences in dry bulk density obtained in Proctor apparatus are approximately up to 0.15 g⋅cm−3.
The development of the common mushroom production sector in Poland and worldwide is accompanied by growing problems of mushroom producers. Production intensification, a constant increase of market expectations, and changing legal regulations, as well as consumers, lead to the situation that producers of common mushrooms have increasing problems associated with the cultivation technology. This situation, therefore, forces producers to look for new solutions. One of such solutions is integrated cultivation of the common mushroom with microbiological preparations. The effect of these preparations on mushroom yielding was investigated in this study.
Due to low effectiveness or high costs of using chemical agents in the protection of common mushrooms, producers are forced to look for alternative methods of protection. One such method is the use of preparations containing beneficial microorganisms. A statistical evaluation of this mushroom protection method and determination of the number of infected fruiting bodies is presented in this paper