INMATEH - Agricultural Engineering

6

Authors: Cujbescu D, Voicu Gh, Bolintineanu Gh, Persu C, Kabaş Ö, Bungescu S, Biriş S.

Romania's strategic objective of EU integration imposes, among others, policies that ensure the implementation of community requirements on the free movement of products, which is based on an open market economy, based on competition and economic and social cohesion. Agricultural productivity (main economic branch through its impact on the society and environment) is influenced by technological level of applied work, sowing work occupying a very important place in these technologies. This paper presents a method for testing the hoeing plants sowing machines with the help of a stand equipped with laser sensors that measure the time interval between the fall of two seeds which it transforms in space and which it compares to the reference area calculated by a specialized software after entering the input data (density, distance between rows, number of holes on the disk, speed)

6

Authors: Gevko R.B, Klendiy O.M.

The article presents the design of a safety device with slipping and axial shifting regimes, which are separated in time and are used in order to recondition the working capacity of a conveyer. Also, power analysis of the operation of a safety mechanism is conducted, which gives the opportunity to estimate the change in the moment of rotation of a driven half-clutch and a screw T depending on the change in the angle of the relative turning of half-clutches . Based on the results of the static experimental investigation of the safety device, it was determined that the given static analytical dependences can be used in the engineering design of different standard sizes of a safety device

6

Authors: Fodorean G, Cioica N, Nagy M, Atanasov At, Covaliu C.

Bioplastics (defined either as bio-based or biodegradable), automotive industry and agriculture are closely connected. On one side, renewable resources from agriculture are basic feedstock for bioplastics manufacturing. On the other side, products made from bioplastic materials have many applications in agriculture, in packaging for food industry, in construction and in automotive industry. If bioplastics are biodegradable, the life cycle can be closed by degrading them in industrial or home composters. The purpose of the work was to explore the relationship between the composition of a ternary bioplastic blends and its mechanical properties. Three polymers were used, PLA, PBAT and PA. PLA (polylactide) is a bio-based polymer produced by Nature Works, designed for injection moulding applications. PBAT (ecoflex F BX 7011) is an oil-based, biodegradable polymer designed for film extrusion and extrusion coating, produced by BASF. PA (platamid HX 2656) is a bio-based polymer produced by ARKEMA, designed to be used in textile industry, for adhesives and coatings. Relationship between blend composition, morphology and impact strength will be given.

8

Authors: Marin E, Bolintineanu Gh, Sorică C, Manea D, Herak D, Croitoru Ş, Grigore I.

This paper presents the results of experimental researches of sowing body, endowed with a pneumatic distribution apparatus equipped with vertical distributing discs and different sized holes, body which is the main component of a modern technical equipment performed by INMA Bucharest in partenership with S.C. MAT SA Craiova. The output obtained following the experimental researches allows to improve the technology of establishing the hoeing plant crops, so that the agricultural machinery market should benefit of a state-of-the art technical equipment in compliance with high quality requirements

8

Authors: Bogdanof G, Păun A, Ertekin C, Neagoe V.

The paper presents the theoretical and practical researches on the achievement and testing of a trailed windrover for fodder harvesting which carries out the operations of mowing, crushing and placing in continous and uniform swath of grassy fodder plants on the ground for natural drying,by a single passing. On the windrover were tested two types of conditioning devices for forages aiming the reduction of harvesting losses for different types of crops

8

Authors: Ludig M, Cârdei P, Muraru V, Mihailov N.

This paper presents some possibilities to optimize the use of electromagnetic waves, microwaves for the being moment, in agriculture and food industry. Concerns on this issue have arisen from some research topics about heating systems for agricultural products in their manufacturing processes. Obviously, at a later time, other interesting applications were suggested. For the present moment, the applications are limited to the drying process of herbs, fruits and vegetables or materials that must be preheated for processing (sawdust for pellets). For future applications, microwaves and other electromagnetic waves can extend their use in complex treatment for stored fruits and vegetables processing, treatment against pests existing in agricultural fields or in other areas. A mathematical model of a microwave oven from specialized literature is used in this paper in order to obtain a better positioning of organic matter inside the oven or a more favorable thermal field inside the oven

8

Authors: Jie Zhang, Zhenzhen Ma, Dengming Wu

This paper studied the non-point source pollution type of Meijiadu Village, Gaocheng Town, Yixing City, Taihu Basin, analyzed the process of rainfall-runoff producing- pollution producing of two main runoff pollution sources in the rural area, calculated the mean concentrations of the different rainfall events. Based on local living conditions and poultry farming methods, the runoff pollution characteristics and the influencing factors were analyzed. Besides, a biological detention pond technology suitable for treating runoff pollution under rural conditions was proposed. The results show: The event mean concentrations of these two polluted areas differed significantly; within the same rainfall, the runoff peak occurred 0.6-1.1 h later than rainfall intensity did, and the concentration was also changed along with the runoff process. However, at different rainfall intensities, the loss law of the pollutants was similar. The concentration of runoff pollution reached the peak within the first 10 min, but the water quality became stable after the stabilization of the runoff. Therefore, the concentration of runoff pollution was affected by rainfall intensity, rainfall duration, poultry scale, human activities, surrounding soil properties and many other factors.

8

Authors: Mărdărescu V.Gh., Ispas N., Năstăsoiu M.

When designing a cylinder head for two families of stationary Diesel air cooled, engines, with direct injection, we have to consider the BMEP, which is limited to these engines to values of 3.8-5.2 bar. To optimize gases exchange process and obtain a desired swirl number, different solutions are studied: geometry galleries, speed location of valves and gas fields concentrations developed in the combustion process for each proposed solution. The paper presents the optimal solution found in the functional analysis made for a program FLUENT single cylinder engine and one engine family bi-cylinder, looking at for each case of cooling air flow. Another aspect to be taken into account when designing the cylinder heads is to determine the thermal regimes of the cylinder head, piston, cylinder, valves and nozzle, in order to define the development of heat per work engine cycle. From our experience in designing and testing stationary air cooled engines and developing of injectors and new combustion chambers, a combustion code, written in C++, simulates the heat release rate per cycle, also serving to define data used to determine required heat transfer. The objectives of this paper are to define optimum construction solutions for a cylinder head for air-cooled Diesel engine with direct injection, having the stroke of 65 and 82 mm bore.

10

Authors: Yaojun Bo, Qingke Zhu, Weijun Zhao

This study was aimed to identify optimal indicators for microtopography-oriented soil quality assessment. Twenty-two soil physicochemical and biological parameters were investigated at 93 sampling points in five different microtopographic units in semiarid regions of the Loess Plateau, where the principal functions of eroded agriculture soils are related to productivity and anti-erosion ability. The selection of soil quality indicators was accomplished using a combination of sensitivity analysis, principal component analysis, and stepwise regression. The indicators used for microtopography-oriented soil quality assessment were found to be moderately sensitive with no high sensitivity. Moderately sensitive soil quality indicators including the levels of sucrase activity (SA), available phosphorus (AP), total nitrogen (TN), soil organic matter (SOM), and urease (UA) are the major objectives of soil quality restoration and regulation in the study area. The 22 soil physicochemical and biological parameters indicative of soil quality were grouped into seven soil quality factors; SOM, water-holding capacity, total phosphorous (TP), total potassium (TK), soil water content, capillary porosity, and AP. Optimal indicators for microtopography-oriented soil quality assessment in the study area were identified as; SOM, TN, SA, UA, AP, TP, CaCO3, APA, and TK. Among these, the SOM level was the key indicator for characterizing soil quality in relation to microtopography in the semiarid loess region. This study provides reference information for the conservation of agricultural soils and improvement of low-yield farmlands in semiarid regions of the Loess Plateau. This will enable better agricultural decisions by the residents and aid decision making by the government according to local conditions.

14

Authors: Nutu N.C., Pana C., Dobre A., Negurescu N., Cernat A.

The need of fresh air breading, especially in congested places and fuel price increasing led to new solutions for Diesel engine fuelling. The alternative fuels are a very good choice regarding pollutant emissions and price decreasing. This paper objective is to highlight comparative aspects between results obtained in the case of fuelling a Diesel engine with Diesel fuel and, respectively Diesel fuel and LPG,in order to be also used at agricultural tractors, either experimentally on test bed, or by thermodynamic processes modeling. The computer software used in this work is AVL Boost, a friendly and powerful environment, built by AVL Austria. The created model simulates a dual mode fuelling of a Diesel engine with Diesel fuel and LPG.

4

Authors: Popa Gh., Buculei M.

In this paper are presented and analyzed the experimental test results for tractor U 650-braking system, in INMA Bucharest laboratory. We determined the torque for the drive wheels of the tractor (Mr), the hydrostatic motor shaft torque (MMh)tangential traction forces (Fm) and braking carriage thrust (Ft).

6

Authors: Dinu I, Popa C., David M.F.

In this paper is presented the press room of the MAC – 3 machine endowed with two pressing mechanisms, while also showing the advantages of the new system. Also the diagram of the two pressing mechanisms is given, while equations are established for determining the speed distribution by using the independent cycle method.

6

Authors: Vieru I., Petrache Gh., Nicolae V., Pârlac S., Neagu E.

This paper presents a first study on dynamic analysis done on a rear axle with torsion beam. The main purpose of this analysis is to establish the natural vibration modes with similar values which are likely to come into resonance. The CAD models of the parts were obtained using CATIA V5 application and the calculation was performed with FEM using MSC/NASTRAN software. The experimental determinations were performed in the vibration laboratory of the University of Pitesti.

8

Authors: Liu M., Wang H.

Agriculture survey and evaluation UAV is kind of advanced high-efficiency agriculture information equipment that can be used to farmland measurement, agricultural insurance assessments and other fields. BeiDou Navigation Satellite System is China’s global navigation satellite system which has been developed independently ， and currently it is rarely applied in agriculture survey and evaluation UAV. Since BeiDou navigation system can only provide location information, an integrated navigation system that composed by BeiDou Navigation Satellite System, Strapdown Inertial Navigation System and Air Data System is proposed to improve the navigation accuracy of UAV navigation system. Integrated navigation system model is established, and to improve the navigation system parameters solving speed, and also to overcome the filtering divergence phenomenon caused by the system model uncertainty, a modified two-step adaptive Kalman filter algorithm for navigation parameters solving is proposed. Simulation results show that the proposed integrated navigation system and parameters solving algorithm can effectively improve the UAV navigation accuracy and prevent divergence of the filter.

10

Authors: Manea I., Gîrnita I., Matache M., Muscalu A., Persu C., Voicea I.

The paper presents theoretical and experimental researches on the use of experimental modal analysis as an instrument of appreciation of fatigue state, as well as to identify the structural changes of the complex mechanical structures. The application is carried out on a railway bogie frame, performed at SC Softronic Craiova, being in course to be tested for static and fatigue stress at INMA Bucharest. Researches are in full progress, in the article being presented the results of initial tests as well as those performed after 6 millions of stress cycles at fatigue.

10

Authors: Xu L., You Z., Wu S., Zhao H., Wu L.

There is little equipment specially developed for grading kiwi fruit in both China and foreign countries. While the full automatic grading equipment often has complex mechanical structure and costs highly, it always grades kiwi fruit on the basis of singular feature such as size, weight, shape, color and surface defect such that it is hard for them to promote kiwi fruit’s market competitiveness. Therefore, this paper developed a set of practical automatic kiwi fruit grading equipment basing on technologies of mechanical separation and conveyance, image capture and processing as well as intelligent control. This set of equipment mainly consists of material storage bin, single-line positioning system, image capture system and grading executive system. And it also has programs of image capture, image processing, grade determination and human-machine interaction for the host computer as well as control programs for the slave computer. Its operating principle is that: firstly put a small amount of kiwi fruits or slowly put kiwi fruits into the storage bin and switch on, and then the host computer sends the startup command to the slave computer. Upon receiving such command, the slave computer starts grading equipment and initializes the camera. The camera will then get into the image capture state. Kiwi fruits are conveyed to the image capture system by the single-line positioning system in single row. Upon the slave computer receives the signal that kiwi-fruits are on position sent by the position sensor of the image capture system, it will immediately send such signal to the host computer. Then the host computer will store the images from the camera at this time and discard the images captured at other time. After the host computer carries out relevant operations such as image processing and grade determination to moving images, it will send grading results to the slave computer. At this time, the kiwi fruits will have been conveyed to the grading implementation area and the slave computer will control the implementation system at all levels to perform grading. Each kiwi fruit will be graded through the same grading flow. By testing, this equipment is capable of grading by three features of size, shape and surface defect and their grading accuracy can reach to 88.9%, 91% and 94% respectively. And the accuracy of integrated grading can reach to 86%. The output of this equipment can reach to 1.22kg/min which is much more than the efficiency of manual grading. With simple mechanical structure and low cost, this equipment reduces the processing cost of kiwi fruit and is suitable to vast middle and small users.

6

Authors: Stefan E.M., Voicu Gh., Constantin G., Ewemoje T.A.

In the paper are presented the theoretical and experimental researches results regarding the particle size characteristics variation of grist coming from breakage phase of wheat seeds on the milling plant technological flow of 100 t / 24h capacity, along with constructive parameters of grinding rolls. For determining the workflow parameters of grinding rolls the mathematical model is presented.

6

Authors: Yaschuk A., Kirchuk R., Dudarev I.

The results of theoretical researches of the process of aeration of bulk material in the cylindrical drying chamber of the dryer [1] are suggested in the article.

8

Authors: Stoica D., Voicu Gh., Plosceanu B., Carp-Ciocârdia C., Moise V., Kabas O.

The dynamical study of oscillatory motion in the horizontal plane of a conical sieve with vertical axis,suspended in three points, is presented in this paper. The sieve is suspended with three elastic cables, in three points, at the top and at the bottom. The differential equations of the sieve motion in polar coordinates have been determined with Lagrange’s equations. The trajectory of the sieve joint point to the acting mechanism was graphically drawn. Analyzing the trajectory of a point on the sieve, some qualitative assessments on material motion on the sieve, in separation process, can be done.

8

Authors: Wang G.

Demand prediction is a hot research field in markets management, especially for fresh agricultural products prediction based on supply chain management. Based on BP neural network, a new demand prediction algorithm for fresh agricultural products is presented in the paper. First, the structure and data indicators of BP neural network algorithm are redesigned and the training function is selected for the fresh agricultural products prediction algorithm. Second, the improvement of excitation function, (including trigonometric function and sigmoid function) and orthogonalizable design, are presented and analyzed to speed up the calculation and improve the prediction accuracy of ordinary BP algorithm. Finally, data from certain fresh agricultural product corporations are taken for example and the simulation results show that not only the problem of convergence speed has been solved, but also the prediction accuracy is ensured when the improved algorithm is used in demand prediction for fresh agricultural products .

8

Authors: Bulac I., Pandrea N.

Technological deviations determine in the intermediate couples of the cardan joint supplementary efforts due to restrained movement. This paper sets as goal the determination of dependency between the technological deviations and the size of these movements.

10

Authors: Lijia X., Chaolin L., Xianping Z., Nan J., Xinbao W.

As the present feeding devices used in the chicken farm are mostly simple and less automated, an intelligent feeding system is established in this paper by comprehensive technological means like sensor detection, data processing and remote monitoring to control the feeding quantity accurately and monitor the feed intake in real time. The system consists of upper computer, control center and mechanical hardware equipment, of which the mechanical hardware equipment is about 44.2kg. Upon testing, the system takes 15s in feeding; the accuracy of feeding quantity is 90-99%, compared with 70-85% of that of traditional machine; the feeding efficiency is 1.4-1.9 times higher than that of traditional machine. Users can set the feeding parameters based on the chicken age, type of chicken and other information through the interface of the upper computer, and monitor the epidemic situation of the chicken farm, to achieve the requirement of intelligent feeding.

6

Authors: Anghel St., Usenko M.

The paper presents theoretical research on modelling and simulation of U-650 M tractor power steering . Starting from developing of the model we realised its simulation following the evolution of main parameters in time. The results can be used to study the behaviour of power steering in operation

6

Authors: Filip Ilie

Nanoparticles have been widely used in polishing slurry such as chemical mechanical polishing (CMP) process. The movement of nanoparticles in polishing slurry and the interaction between nanoparticles and solid surface are very important to obtain an atomic smooth surface in CMP process. Nanoparticle’s behavior in the slurry with law viscosity has a great effect on the wafer surface in polishing process. Hydrodynamic pressure is periodically generated on the surface of asperity when nanoparticles are passing through the zone. Due to the periodical pressure, fatigue fracture occurs and begins from the top to the bottom of the asperity, then the material on the top is removed. Removal rate is calculated based of energy theory of balance fracture , and result shows a good agreement with experiment data. In this paper we present both experimental and theoretical studies on the movement of nanoparticles in polishing slurry and collision between nanoparticles, as well as between the nanoparticles and solid surfaces in time of process of CMP by exploring a model of microscopic friction based on the surface topography. Experimental results have proved that the nanoparticle size and slurry properties have great effects on the polishing results. The effects of the nanoparticle size and the slurry film thickness are, also discussed.

8

Authors: Dutu M.F., Maican E., Dutu I., David L., Rusănescu C.O.

This paper presents the two degrees of freedom of mathematical modelling of a tractor wheel. The tractor is a complex mechanical system that, while traveling, is subjected to vibrations that are transmitted from the running path to the driver. A modelling program was used in order to study the tractor movement on agricultural land. Useful charts were developed for: amplitude variation of the tractor’s mass center oscillation, with traveling speed; amplitude variation of the angle of rotation of the tractor around its center of mass; amplitude variation of the driven wheel with speed; driving wheel’s amplitude variation; amplitude variation of vertical force acting on driven wheel, with speed; amplitude variation of vertical force acting on driving wheel, with speed. There are also presented the study results for a tractor traveling on a country road. Interpretation of results is based on charts for amplitude variation of the tractor’s center of mass, amplitude variation of the angle of rotation of the tractor around its center of mass, amplitude variation of the driving and driven wheel when tractor is moving, amplitude variation of vertical force acting on driving and on driven wheel, with speed.

8

Authors: Constantin G.A., Voicu Gh., Stefan M.E., Paraschiv G.

In the paper it is presented the flow diagram of the wheat breakage phase in a milling plant with the capacity of 4.2 t/h, as well as the experimental results of the granulometric analysis of the grist from the plane sifter compartment of the Second Break. It is presented the particle size distribution of the grist that comes from the grinding rolls, but also the five grist fractions in which it is divided into plane sifter compartment of respective passage. Experimental data obtained for the particle size distributions of grist fractions were tested by computer regression analysis , with known distribution laws: Schuhman, Rosin-Rammler, Gauss and log-normal, determining the values for the equations coefficient and the correlation coefficient R2.

10

Authors: Moise V., Biris S.St., Kabas O., Ungureanu N., Vlădut V., Boureci Gh., Stroe I., Caba I.L.

To establish a machinery system and the optimal mechanization technologies for different types of agricultural farm and for various specific conditions it is necessary to use scientific methods of optimization. The success of a business, including agriculture, is determined by the amount of profit, which depends on the quality and quantity of the achieved product. To determine the minimum surfaces from which a certain power range of tractors becomes profitable, the income limit must be equal to the costs required to perform works in that area. In this paper is determined the optimal surfaces matrix for 20-65 HP tractors, used in family farms. For the determination of the minimum surfaces, incomes and necessary costs for the considered works must be taken into account. The optimal usage time of the tractors, the matrices of aggregates yields, as well as the matrix of equipment costs are also determined. Various methods of numerical optimization are used. After running numerical calculus and optimization programs, has been observed that, in case of family farms, the minimum surfaces from which a certain power range of tractors becomes profitable decreases if the work is performed by the farmer, with personal equipment. It has also been observed that the minimum surface required for the profit to be equal to zero at the limit, decreases with higher quality of the equipment.

10

Authors: Boja N., Boja F., Caba I., Gligoras D., Dărău P. A.

The present research displays the results obtained after the digging of holes for planting saplings in a previously unprepared soil, following the steps to carry them out according to some physical-mechanical properties of the soil. The research was carried out on a horizontal ground in the O.S. Iuliu Moldovan, in two arranged unities (parcels) 31 C and 32 A, in a previously unprepared ground, on two types of soil: gley-soil (the muddy subtype) and alluvial soil (the vertical-gleyed subtype), and in O.S. Radna, u.a. 74, on a brown typically luvic soil, using the Stihl BT 121 motto-borer with a 150 mm drill. The objectives of the research were to make a comparative determination, on different types of soil, of the qualitative parameters, among which the most important ones are: degree of loosening of the soil taken and left in the hole, resistance to penetration, resistance to shearing, timing of drilling holes, degree of scattering of the soil taken out from the hole, degree of evacuation of the soil from the hole, gas consumption for the drilling of the hole, using the Stihl BT 121 motto-borer in order to establish its technical efficiency. In order to observe the influence which the drilling of holes have on walls, we measured the resistance to penetration and resistance to shearing every 10 cm at a 30cm depth, the proper depth for planting small-sized saplings, on two opposite sides, so that we could get the most probable values of these physicalmechanical properties of the soil. After taking the measures in order to establish the compaction degree of the wall and of the bottom of the hole by the borer in that interval, it was judged that in conditions of normal humidity, if the borers have sharp knives and are well conceived and executed in technical terms speaking, there are no big values of the resistance to penetration which could affect the subsequent development of the saplings.

6

Authors: Păun A., Nedelcu A., Neagoe V.

Productions of fodder crops harvested by the combine vary depending on the harvesting period, climate and soil conditions, plant growing level. Within the combine working process, the chopping drum is the most important working part, that is why three constructive variants, frequently used in fodder combines manufacturing, have been studied. The paper present the results of experiments performed for the trailed combine (CTF), endowed with equipment for harvesting grass fodder(EI) and ensiling corn (EP) and with three constructive variants of chopping drum.

6

Authors: Moiceanu G., Voicu Gh., Paraschiv G., Poenaru I.C., Pirnă I.

In nature the elements of a biological cluster, as they are just after harvesting or the material particles of a ground material never randomly distribute completely, but only after various distribution laws known in mathematical statistics. These distribution laws or functions can be Gauss laws, Lorentz laws, Euler laws etc. They can be graphically represented through two different curves: the probability density curve (the distribution curve) and the cumulative distribution law. The distribution functions are characterized by many specific parameters: average, standard deviation, limits, asymmetry etc. Studying different phenomena, in can be seen that although these belong to a different science, their distribution in frequency is alike, respectively the histograms have the same shape. For example, 90% of the physical phenomena can be explained with the normal distribution law (Gauss – Laplace law). In this paper a statistical study of physical–biological characteristics of two Mischanthus crops harvested in two consecutive years is presented: plants distribution according to height, the plants individual mass, plants diameter at the lower internod and at the upper internode, etc. There were determined the statistical parameters for various distribution laws (normal law, lognormal law, gamma law) which can point out the physical characteristics remembered before. Also, the specific mass of plants stalks was determined, based on its two components, bark and core, and also the energy consumption during stalk grinding process.

6

Authors: Patamanska G., Chehlarova-Simeonova S.

In recent decades changes in climate of Bulgaria have been observed, a warming trend was established, coupled with decreasing rainfalls, especially during the warm half of the year. This causes reduction of the agricultural production and prevents development of intensive agriculture without irrigation. There is a need for changing the existing irrigation systems towards improving their operation and management in order to develop productive, sustainable against altered climate conditions agriculture, which uses resources efficiently. The present article aims to analyze and evaluate the existing problems facing the irrigation sector in Bulgaria and to identify the main reasons for developmental delay. Key measures to be adopted for changing and renovation of existing irrigation systems and their management in order to increase the level of application of irrigation and water use efficiency are outlined.

8

Authors: Nagy E.M., Cota C., Cioica N.

In our country, at present, about 90% of the rural population uses the solid biomass as a source of heat. In Romania, biomass represents an important source of energy not only in rural but also in urban areas. Under these circumstances it is important to know the potential of biomass, both theoretical and real, not only at national level, but also divided by region or even in certain clearly defined areas. This paper brings in a general method for evaluate the energy potential of solid biomass at national level. The proposed method is based on systemic analysis on the one hand, and on the other hand, is based on utilization of statistics available at national level, and it can be applied to determine the energy potential of biomass coming from only a certain vegetal or wooden category, or from a certain area clearly defined. Also, in the present work is performed the evaluation of the real energy potential stored in agricultural residues resulting from harvesting of 10 ha of wheat. This method of evaluation is useful in determining the real energy potential of solid biomass and allows farmers to choose correctly the category of biomass grown to be energetically capitalized.

10

Authors: Cârdei P., Sfîru R., Stefănoiu M.D., Bădescu M., Boruz S., Lazar S.

This article is the first among a series of three articles describing mathematical models of fodder harvesting combines energegetics, in order to optimize their working regimes. Starting from scientific literature of 1970-1980s, the classical models have been improved and adjusted, obtaining new models and results. The calibrating method of mathematical models is shown in order to determine the model constants which are not given by specialty literature. There are made references to manner of validating the results and possible applications in a wider domain of technique and science. The three articles are structured according to complexity of mathematical models elaborated and used for optimization. The first article deals with generalities and unidimensional model, namely that model considering a unique speed for working regime, idle speed and at turnings. The second contains models that consider the working speed and turning speed equal to idle speed, and the third one will describe the models containing the three speeds as independent variables.