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Mathematical Models for Nonlinear Soil Behavior

Abstract

Actually, the seismic movement has an irregular cyclic character.This can be equivalent to a determined number of uniform cyclical stresses equivalent in terms of effect.

Modeling the behavior of the soil to cyclical stress, is usually done, by establishing a relationship for primary loading like τ = f (γ) and after drawing the diagram “effortless strain curve”, in which τ is the stress, and γ is shear deformation. For modeling nonlinear behavior of the soil, we used like nonlinear models. The best known are the hyperbolic model and the Ramberg-Osgood model.

Open access
Modelling of the Separation Process of the Potato Stack

Abstract

The most time consuming and the least mechanized process of potato cultivation is its harvesting. Therefore, now, as never before, we have faced a problem concerning the improvement of the existing and construction of new devices for potato harvesting and their provision to the cultivation industry. It requires further development of theoretical, complex and extensive research on the phenomenon of separation of the potato stack, which will enable justification of optimal work modes of the existing separating devices and will be used for the synthesis of basically new, more advanced separators

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Parametric Study on How the Lateral Forces Acting on a Deep Foundation Influences the Axial Forces Developing in the Piles

Abstract

A missing piece in the design of bridge substructure is that the equation given in structural mechanics that assesses the axial forces in the piles of a deep foundation does not take into account the effect of lateral forces acting on the pile cap. In practice, pile forces are determined using a FEA software. This method, however, can not be easily incorporated into an automated program that performs local and global optimizations of a structure. One of the reasons is that this method is particularly demanding on the computational resources. Since a bridge can have a number of deep foundations, which must be verified for various combinations of actions, which need to be optimized, recalculated in various scenarios and then the entire process reiterated for all structural solutions, computational cost can become prohibitive. Another reason is that due to the lack of a relation between all the parameters and dimensions that influence the behaviour of a deep foundation, their optimization is difficult.

For this purpose, a parametric study has been carried out to investigate what parameters influence the relation between the lateral forces applied to the foundation and the axial forces that develop in the piles, and ultimately propose an equation that takes into account the lateral forces. The study is carried out using experimental data obtained on models using the finite element analysis method using SAP 2000 (v.15) software.

Open access
The Sunet System for Monitoring Noise Pollution in Cluj-Napoca

Abstract

In Europe the need for local authorities to provide a high standard of living for their communities led to the establishment of the European noise mapping directive 2002/49/EC. Whilst Noise mapping itself doesn’t need continuous noise monitoring, states must produce a noise action plan which highlights actions they intend to take to reduce the number of people affected.

SUNET platform (System for Urban Noise and Eco-Traffic) was designed for improved management of the noise pollution in Cluj-Napoca and to provide up-to-date public data on a user-friendly interface. The implementation of the application over the entire municipality is highly advantageous for it creates a link between the town’s administration (the local authorities, the City Hall of Cluj-Napoca) and the user (the citizens) through this system which is dynamic, modern and compliant with the European regulations.

Open access
Analysis of Power Equipment Level on the Example of Farm Tractors in Selected Farms of Przeworsk Province

Abstract

Decisions concerning investments in farm tractors is a significant problem of modern agricultural production. Ensuring efficient performance of agrotechnical treatments and a rational level of use of tractors in the aspect of exploitation costs are a derivative of the power equipment level in a farm. The paper presents studies carried out in 31 selected farms, which run production on the total acreage of 937 ha of agricultural land (AL) and exploit 70 tractors. Analysis covered information on: area of farms, number and power of used tractors, investments in technical equipment concerning purchase of farm tractors and a production profile. In the investigated farms at the average per 100 ha of the agricultural land area there was 7.47 tractors, 90% of respondents actively used subsidies available from the EU structural funds. A high energy equipment level was determined in particular in farm with a smaller acreage. Over 87% of farm used more than one tractor and the age of the third each did not exceed six years.

Open access
Assessment of Changes in Sod Under Intensive Use

Abstract

The paper presents research results which aimed at evaluation of the change in the sodding degree and selected strength parameters of sod used with varied intensity; additionally sod was modified through administration of biopreparation. Measurements were taken on two types of sod. The first one was formed from perennial rye grass, the second one from orchard grass. It was proved that the use of the investigated facilities resulted in reduction of sodding, which was related to the sod forming species. No impact of biopreparation use on the sodding degree was proved. Intensive use affected the increase of the value of the analysed strength parameters; at low soil moisture (5.0-5.5%) considerable compaction in the surface layer of soil was reported.

Open access
Assessment of Selected Technical Parameters of Soya Seeds Oil Pressing Process

Abstract

The objective of the paper was to determine the impact of the value of the oil pressing pressure with the cold pressing method in a screw press on the pressing course and performance. Varied values of pressure were obtained through the use of three replaceable attachments of the pressing unit with a varied diameter of the outlet conduit (ф1=2 mm, ф2=4 mm and ф3=6 mm). The soya oil pressing process performance was determined in relation to the applied attachment and the soya cultivar. Seeds of 7 Polish non-genetically modified soya cultivars constituted research material. It was proved that both variable pressure values and the used soya cultivars have impact on the pressing performance. Based on the analysis of the obtained research results it was proved that varied technical parameters and soya cultivars influence both the process performance and the remaining parameters and pressing conditions.

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Evaluation of the Improvement Possibilities of Physical Properties of Mineral Fodder Additives

Abstract

The paper presents a change in physical properties of loose, dust fodder additives (aluminosilicate) after mixing them with oil or glycerine. Additives where mixed in a blade mixer with the same mixing time for all samples, which was 1 minute. Tests with oil or glycerine were carried out in the following amounts: 5%, 10%. For mixtures of additives with oil or glycerine a selected group of physical properties was determined. Method of determination of physical properties was the same for all samples i.e. the same additives − without oil and glycerine as well as mixtures with their participation. Obtained research results and their analysis unanimously indicate that adding any amount of oil or glycerine for additives improves selected physical properties of mixtures.

Open access
Fuel Consumption, Work Time Expenditures and Winter Wheat Yield in Case of Non-Tillage and Strip Soil Cultivation

Abstract

A single-factor field experiment concerned calculation of fuel consumption, time expenditure of the working time of machines, and winter wheat yield size in three technologies of soil cultivation. Fuel consumption in the tillage and non-tillage technology was comparable and amounted approximately to 31 l·ha−1, but the highest consumption was generated by basic soil cultivation (tillage or heavy cultivation cultivator). Fuel consumption in the strip cultivation technology was the lowest and it was 23.0 l·ha−1. Non-tillage cultivation allowed reduction of the time necessary to carry out the wheat cultivation technology by 28.8% (in comparison to tillage cultivation). On the other hand, strip cultivation allowed reduction of the total time of machines operation by 48.5 % (in comparison to tillage cultivation). The yield of winter wheat cultivated in the non-tillage technology was at the average by 4% better than the one cultivated in tillage cultivation. The highest yield of seed (7.63 t·ha−1) was obtained in the strip cultivation technology (by 6.7% in comparison to tillage cultivation).

Open access
Impact of Feed Mixture on Kinetic Strength of Pellets for Poultry

Abstract

The paper presents the impact of feed mixtures for poultry on their kinetic strength determined with Holmen's method. Research material came from a production line and 9 pelleted feed mixtures for poultry with diameter of 3.2 mm were accepted for the research. Feed was prepared, pelleted and cooled with the use of the same devices and their exploitation settings were comparable with regard to the investigated feed pellet. The obtained research results proved that kinetic strength of the investigated feed pellets was statistically significant in relation to the composition of the feed mixture. Relations of kinetic strength of pellets to the composition of the feed mixtures were determined with the multiple regression method. From the determined models the highest utilitarian value may occur in case of a model with four explanatory variables: corn (x1), wheat (x2), soya meal (x4) and fat (x5).

Open access