Analele Universitatii

11-22

Authors: Performance Evaluation of an Egusi-melon Washing Machine

Traditionally, woven basket in the flowing water stream with heaps of melon balls at the washing site is being employed in washing of Egusimelon seeds in most local settings in Nigeria. This traditional melon washing method was observed to be associated with high level of drudgery ranging from the famers developing pains all over the body, infection with water-borne diseases and low washing output. In this study, Egusi-melon washing machine was fabricated in the Department of Agricultural and Bio-Environmental Engineering of Auchi Polytechnic, Auchi, Nigeria.The machine after construction was evaluated using a factorial experiment in a Randomized Complete Block Design (RCBD) involving three levels of speed (1008, 1482 and 1901rpm), three levels of feedrate (2.6, 3.3, and 3.9kg) and three levels of sieve size (6.0, 7.5 and 10.5) in three replications. The result obtained was statistically analyzed using SPSS 19.0 software and Duncan’s New Multiple Range Test (DNMRT) to determine the level of significant among the treatment factors. However, the performance parameters considered for measurement are Washing Efficiency and Washing Capacity. Washing Efficiency and Washing Capacity of 80% and 1.16kg/min respectively was obtainedat Speed of 1008 rpm, Feedrate of 2.6kg/min and sieve size of 7.5mm. Also, the result of the statistical analysis shows that the machine speed, federate, sieve size and the interactions between them are all significant factors on the Washing Capacity and Washing Efficiency of the machine at 5% confidence level.

29-34

Authors: Daniel Mihai Amariei, Alexandru Victor Amariei

In the present paper we are presenting a problem of distribution using the Network Modeling Module of the WinQSB software, were we have 5 athletes which we must assign the optimal sample, function of the obtained time, so as to obtain the maximum output of the athletes. Also we analyzed the case of an accident of 2 athletes, the coupling of 3 athletes with 5 various athletic events causing the maximum coupling, done using the Hungarian algorithm.

43-50

Authors: Olga-Ioana Amariei, Codruţa-Oana Hamat, Liviu Coman

The present paper presents an optimal allocation mode of the machines in a manner to maximize the profit. Starting from provided data – time standard, technical itineraries, production volume, working regime and continuing with the determined ones – duration, necessary number of machines, unit profit, the problem became a maximization transport problem

59-68

Authors: Silviu Razvan Avram, Tiberiu Stefan Manescu

This paper deals with technical matters relating to the protection of existing and innovative riverbanks, farmland and homes in case of natural disasters. Also includes comparative presentation of proposed solutions regarding the advantages and disadvantages occurring during developments.

79-84

Authors: Remus Belu-Nica, Relu-Costel Ciubotariu

In the paper are presented concrete data on developing technological batches of metal composite material (MCM) type Silumin 3-reinforced matrix with steel mesh S235JR, with the indicating of the parameter and of the distinct stages of work. The samples from prepared batches were cut along and across by water jet abrasive process and were subjected to a destructive testing program and microstructural examination, obtaining results in concordance with the desired quality. The abrasive material used for cut was GMA granite with the average mesh of 80, the particle size ranging between 150-300 μm, density 2300 kg/m3 and melting point 1240°C.

93-96

Authors: Cornel Bit

This paper presents a new type of mechano – optical force transducer which to be used in different mechanical experimental investigations. This transducer has been integrated within a mechanical modulus, providing a useful tool for this kind of measurements. The use of optical methods for the elastic contact measurements has several important advantages.

107-116

Authors: Adelina Bostan, Nedelcu Dorian, Florin Periș-Bendu

In practice, for the design of hydraulic turbines, laboratory tests performed on reduced scale models of turbines are recommended. The optimisation of a turbine model requires extensive experimental research on several variants of geometry, the improvement of efficiency at an industrial scale which will lead to substantial economic benefits because of the extended life of the turbine. Warranty conditions arisen from model tests will be verified by additional tests performed on industrial prototypes at specific points agreed between the supplier and the customer. The purpose of these tests is the experimental determination of the relationships between the basic parameters of the operating turbine for different operating conditions. The graphic expression of these relationships represent the hill chart of the turbine which is valid for the whole turbine family similar to the tested model.

127-137

Authors: Navid Bozorgan

Nanofluids are expected to be a promising coolant condidate in chemical processes for heat transfer system size reduction. This paper focuses on reducing the number of turns in a helical coil heat recovery exchanger with a given heat exchange capacity in a biomass heating plant using γ-Al2O3/n-decane nanofluid as coolant. The nanofluid flows through the tubes and the hot n-hexane flows through the shell. The numerical results show that using nanofluid as coolant in a helical coil heat exchanger can reduce the manufacturing cost of the heat exchanger and pumping power by reducing the number of turns of the coil.

152-166

Authors: Sergiu Ciprian Catinas

A detailed investigation of the RC elements subject to horizontal forces and the effect of the rotational stiffness were conducted in this paper by using numerical methods. Since the early ‘1960 this technique become used by engineers but only in the last decade, due to the development of the computing machines the method was used on a large scale. The paper deals with a technique. The paper deals with a summary of recent techniques in manipulating the stiffness matrix of the constitutive materials in efficiently solving problems related to connection between horizontal forces and rotational stiffness. The paper propose some practical methods deducted from theoretical formulation of the stiffness matrix and propose new formulation of the stiffness matrix for this completely applicable to the new technique. At last the paper analyses a three level RC structure using a FEM based computer soft with the method proposed and delivers the results.

175-184

Authors: Adrian Cuzmoş, Constantin-Viorel Câmpian, Doina Frunzăverde, Cosmin Dumbravă, Ana-Maria Budai

The paper presents the tests recommended by the standards to be performed on a hydraulic turbine on commissioning, after repair works or refurbishment, and the manner in which these tests were executed in a hydro power plant equipped with a 75-MW Francis turbine and the results obtained.

195-200

Authors: Silviu Draghici, Eugen Raduca, Cristian Rudolf

The transcoder we have set out to synthetize and to simulate in this paper is important due to the fact that it brings into discussion and also presents the family of weighted and unweights binary decimal codes, presented in binary sequences of 4 bits each. Some of these are used even today with great success in the technique of data transmission, especially in recognition and access keys to certain dedicated programs and soft wares. The binary symmetric code is among the first binary decimal weighted codes, which has been the basis for the creation and development of other such codes. Therefore we have set out to design and simulate such a transcoder.

217-222

Authors: Ioan Halalae, Patrik Silvester Bojan

Computational Geometry is currently using approximation techniques based on convex polygons, with good results in some topics, but with severe limitation of applicability. In this paper we present the first step of a larger project, aiming to lead us to the plane projection of a 3D surface obtained by intersecting two cylinders (a very frequent problem in obtaining the stencils for welded ensembles). As a first step, we present an algorithm for experimentally obtaining the intersection curve of two cylinders. The new paradigm and also the fundamentally new aspect of our project is that we construct our algorithm by simulation of the analytical relations describing the curve, and not by approximation using convex polygons.

231-238

Authors: Sava Ianici, Draghiţa Ianici

The paper presents the design construction and functioning of a new type of harmonic gear transmission named double harmonic gear transmission (D.H.G.T.). In the second part of this paper is presented the dynamic testing of the double harmonic gear transmission, which is based on the results of the experimental researches on the D.H.G.T. The authors present the results of experimental research, enabling a scientific interpretation of the dynamic behaviour of the D.H.G.T., on the mechanical efficiency and the stress state of flexible wheel.

247-260

Authors: Imanogor P.A., Ovibiagele Umahon, Ugbodaga M.E., Omholua A.O.

Direct measurement of surface runoff is often associated with errors and inaccuracies which results to unreliable hydrological data. An automatic Runoff-meter using tipping buckets arrangement calibrated to tip 0.14 liter of runoff water per tip with an accuracy of ± 0.001 litre was used to measure surface runoff from a steel bounded soil tray of dimension (1200 mm X 900 mm X 260 mm) filled with sand loamy to the depth of 130 mm and inclined at angle (00, 50 ,120 and 150) horizontal to the instrument. The effect of varying angles of inclination on runoff intensity, sediment loss rate and sediment loss is significant at 5 % confidence level, while surface runoff is not significant at 5 % confidence level. Total highest sediment loss of 458.2 g and 313.4 g were observed at angle 150 and 120 respectively. Total surface runoff of 361.5 mm and 445.8 mm were generated at inclined angle of 00 and 50, while at angle 120 and 150, 564.3 mm and 590.0 mm of surface runoff were generated. In addition, runoff intensity and sediment loss rate were highest at angle 150, while the lowest values of 1.5mm/min and 5.43 g/min were obtained at angle of inclination 50. The results showed that strong relationship existed among the hydrological variables as a result of subjecting the steel bounded soil tray to different angles of inclination. Such results would provide useful data for the running of physics-based deterministic model of surface runoff and erosion which will be useful for the design of hydrological structures, land use planning and management.

277-284

Authors: Cincă - Ionel Lupinca, Constantin Marta

The solidification study of the antifriction Sn-Sb alloy (HM07) cast on a steel bearing plate in order to obtain bimetallic bearings sized 330xΦ220 is presented in this paper, where the solidification study of the antifriction alloy is also reflected, using a corresponding simulation software (AnyCasting 10). The paper also contains, on the basis of pictograms regarding the solidification simulation study of the HM07 alloy and the metallographic structures realized on the component parts of the bearing and with the help of the electronic microscope and of the scanning electronic microscope, constructive conclusions for production are presented in order to help diminish losses of flaw castings.

295-304

Authors: Dorian Nedelcu, Adelina Bostan, Florin Peris-Bendu

The paper presents the Hydro Hill Chart - Francis module application, used to calculate the hill chart of the Pelton, Francis and Kaplan hydraulic turbine models, by processing the data measured on the stand. After describing the interface and menu, the input data is graphically presented and the universal characteristic for measuring scenarios ao=const. and n11=const is calculated. Finally, the two calculated hill charts are compared through a graphical superimposition of the isolines.

315-322

Authors: Arina Negoițescu, Adriana Tokar

The amount of emissions released into the atmosphere by polluting sources was significantly reduced due to the limitations introduced by the EU. Since one of the main sources affecting air quality is the car, researches regarding the influence of various factors on exhaust emissions are carried out. As CO2 is the main pollutant responsible for the greenhouse effect, the article treats the influence of vehicle load and traffic levels, running modes, the electric consumer’s utilization, and driving style on CO2 emissions for cars equipped with diesel engine. The results from the conducted study can contribute to adopt solutions in order to decrease the concentration of CO2 emissions from cars equipped with diesel engines.

333-344

Authors: Olotu Yahaya, Evboifo Nathaniel, Okafor M.C., Ayilaran C.I.

Aiming at contributing to an adequate management of water resources, accurate estimation of reference evapotranspiration (ETo) using evaporation pan, FAO-Penman and CROPWAT model is very important for the computation of Egusi-melon crop evapotranspiration (ETc) at different stages of crop growth and development. The study was carried out at Research and Experimental Farm of Auchi Polytechnic, Auchi with area of 6.45 m2. Measured daily evaporation depth and weather parameters for 52-day was used to compute reference evapotranspiration using evaporation pan, derived FAO-Penman and CROPWAT version 8.1 models. The maximum and minimum of EToPan, EToFAO-Penman are 4.1 mm; 5.7 mm and 3.5 mm; 4.2 mm. These values were applied to compute maximum and minimum crop-evapotranspiration (ETc) at initial crop developmental stage as 3.4 mm; 0.68 mm respectively. The maximum and minimum intermediate and maturity values for EToPan, EToFAO-Penman and ETc; 4.0 mm;0.7 mm, 3.9 mm; 0.5 mm ,3.4 mm; 0.68 mm and 0.7 mm; 3.0mm; 0.6 mm; 4.1 mm, 0.46 mm;3.25 mm respectively. The melon crop and evaporation pan coefficient for the three different stages are 0.15; 0.85; 0.60 and the pan coefficient ranged from 0.71 to 1.00 and total rainfall and irrigation depths were computed to 226.9 mm and 46.7mm.

359-368

Authors: Ioan Pădureanu, Marcel Jurcu, Ladislau Augustinov, Cornel Hațiegan, Eugen Răduca

The safe operation of a hydro generator depends on its thermal regime, the basic conditions being that the temperature in the stator winding fall within the limits of the insulation class. As the losses in copper depend on the square current in the stator winding, it is necessary that the cooling water debit should be adapted to the values of these losses, so that the winding temperature falls within the range of the values prescribed in the specifications. This paper presents an efficient solution of commanding and monitoring the water cooling installations of two high-power hydro generators.

381-384

Authors: Iulius Petrica, Adrian Valentin Petrica

This paper presents the results of experimental electric welding with pressure butt of ribbon saw blades. The analyzes and tests carried out resulting conclusion is that this process is the best solution for the refurbishment of these blades, provided to make a comeback heat treatment after welding.

397-404

Authors: Irina Maria Terfaloaga

A frequent problem in numerical analysis is solving the systems of equations. That problem has generated in time a great interest among mathematicians and computer scientists, as evidenced by the large number of numerical methods developed. Besides the classical numerical methods, in the last years were proposed methods inspired by techniques from artificial intelligence. Hybrid methods have been also proposed along the time [15, 19]. The goal of this study is to make a survey of methods inspired from artificial intelligence for solving systems of equations.

415-424

Authors: Adriana Tokar, Arina Negoițescu

For the energy consumption reduction in the buildings sector, EU proposes guidelines regarding energy performance. EU Member States must take measures to ensure the conversion of buildings into nearly zero energy buildings, which should also include measures to optimize installations for domestic hot water (DHW). From this point of view the present paper deals with issues regarding hot water recirculation and control aiming to reduce fuel consumption necessary for DHW preparation. To this end the benefits of DHW preparation process optimization were analyzed, in order to ensure a theoretical constant temperature having values in a narrow domain and an efficient thermal fluid distribution in the network for better controlling hot water temperature.