Analele Universitatii

23-30

Authors: Alimasunya E, Olotu Yahaya, Muhammed N.

Charcoal-powered bread baking oven was developed and evaluated with functional efficiencies of 91.2% and 92.1% for baking dough of mass 0.5kg and 1.5 kg to bread at BP of 27.7minutes, 35.9 minutes with the baking temperature (BT) of 153.8oC and 165.9oC respectively. Baking temperature-heating interval of the oven as computed at 100oC at 20 minutes at charcoal emitted heat of 861000 KJ. The oven has the capacity of generating 455.9oC at 270 minutes time interval. The oven has bread baking capacities of 56, 36, 28, 22 and 18 pieces of bread per batch operation using dough mass of 0.5kg, 0.75kg, 1.00kg, 1.250kg and 1.500kg respectively. It is sensitive to the baking time and temperature in relation to dough mass with resolution value of 0.22. Charcoal-powered oven, is cheap and efficient and can be used both in the rural and urban settlement for domestic consumption and smallscale business.

39-44

Authors: Daniel Mihai Amariei, Alexandru Victor Amariei

In this paper aims the application through the Markov Process mode, within the software product WinQSB, Markov chain in the establishment of the development on the market of five brands of athletic shoes.

53-

Authors: Olga-Ioana Amariei, Codruţa Oana Hamat

In this paper an optimization is carried out through simulation of the production flows of two production systems of lower rank. A methodology of simulation-optimization is developed, starting from the general methodology for achieving a simulation process. The system to be simulated is a new system, not an existing one that has to be improved.

67-72

Authors: Petru Chioncel, Nicoleta Gillich, Cristian Paul Chioncel, Elisabeta Spunei

This paper presents an application of digital cascade control implemented in Scilab / Xcos environment, using a P type regulator for the position adjustment circuit, a PI controller for the speed circuit adjustment; the current respectively moments control circuits are rendered by elements of PT1 type. On this basis the program is done in Scilab and the related signal block diagram implemented in Xcos; through simulation, the step response of the system is analyzed for different sampling times.

89-94

Authors: Tudorel Ene

The paper theoretically analyses the influence on the MIG-MAG welding process of additional preheating at the free end of the electrode wire by one or several heat sources, produced by independent current sources, and the modifications required by the welding equipment, consisting in the use of a system of electrode wire feed with the electrode wire advance speed depending on the arc voltage (SVD).

103-114

Authors: Tudorel Ene

The paper refers to the design of a direct current electromagnet, located on the head of a swan neck welding gun of a MIG welding equipment and used for magnetising the rotation space of two additional electric arches, in order to preheat the electrode wire and of the protective gas, partially turned into plasma jet. We present the constructive - electromagnetic dimensioning and the verification of the electromagnet operation.

121-126

Authors: Draghiţa Ianici, Sava Ianici

The paper presents the kinematic analysis of the double harmonic gear transmission by comparative determining of the transmission ratio for two constructive variants of these transmissions. It demonstrates the viability of double harmonic gear transmission (DHGT) by presenting the operating principle and calculation of transmission ratio by using the analytical method of inversion motion. We performed a comparative analysis of transmission ratio for the two kinematic models of DHGT (z2 = z'2, respectively z2 ≠ z'2).

135-144

Authors: Imanogor P. A., Unuigbe O.M.

The acceptance and continuous use of any innovation is the ultimate objective of extension programme. However, extension efforts have failed to avail farmers with some beneficial research-based agricultural technology. There are various factors which predispose farmers to the adoption of any innovation. This study was carried out to find out what factors would favourably dispose farmers to the adoption of irrigation technology. The study was done in the three senatorial districts of Edo State. A total of one hundred and fifty farmers were interviewed of which fifty nine were adopters of irrigation technology. Personal characteristics of farmers which were found to significantly influence the adoption of the innovation include farm size, level of education, social participation and contact with extension agents with a significant index value of 0.88. However the required impact desired through extension service is yet to be appreciated.

155-172

Authors: Tosin Jemilehin, Michael Adu

An electrocardiogram (ECG) is the graphical record of bioelectric signal generated by the human body during cardiac cycle, it tells a lot about the medical status of an individual. A typical ECG waveform consist of the P, Q, R, S and T wave. The automatic ECG signal analysis comprises of using computational method/approach in extracting important features and classification of ECG waveform. This paper presents a concise ECG circuit design using an instrumentation amplifier and a band-pass passive filter. It also present the process involved in analysis of ECG signal. The first stage is the pre-filtering stage, followed by feature extraction of the signal. QRS complex is first extracted followed by P and T wave detection, also the FFT of the signal is also extracted. These features are fed into the classifier for proper classification. A pattern recognition neural network is used for classification, prior to the full deployment of the neural network, it is trained by pre-recorded ECG signal downloaded from the MIT/BIH Arrhythmias database. The neural network gave a satisfactory result with accuracy of around 87%.The whole ECG signal analysis is packaged into a MATLAB GUI for ease of use.

183-188

Authors: Cristian Marius Mimis, Tiberiu Stefan Manescu, Razvan Avram

Butterfly valves in hydroelectric scheme are safety elements that ensure tightly closed access water into downstream equipment. The operation conditions of the biplane disc butterfly valve are subjected to cycles of varying loads. The paper present the lifetime of the butterfly valve disc by using the Soderberg mean stress theory to find the minimum number of cycles which the disc can be loaded and unloaded during the operation of the butterfly valve.

195-202

Authors: Arina Negoițescu, Adriana Tokar

In the paper is analyzed thermal solar systems efficiency from the point of view of energy savings and pollutant emissions concentrations exhausted during these installations operation. For this purpose were taking into account four versions of solar panel systems combined with different types of conventional heating sources, for which were simulated the operation conditions. As a result of the simulation, there were obtained the values of energy savings and pollutant emissions during the four systems operation. By analyzing these values, the combined thermal system optimum solution was selected.

211-221

Authors: Oyati Edith Nwabuogo, Olotu Yahaya

Annual rainfall is of great importance to every nation and provides useful data on agricultural, hydrology and hydraulics designs. The research study presents the evaluation of the hydropower potential of river Orle using the analytical potential interpolation of hydrological elements (Rainfall, river discharges e.t.c) with emphasis of developing 1.032 MW power plant-reservoirs. Hydropower is a renewable energy source based on the natural water cycle and most mature, reliable and cost-effective renewable power generation technology. Gumbel’s Probability Distribution method, U.S Soil Conservation technique and empirical formulation were used to estimate maximum flood design, rainfall distribution and intensity and peak river flow. The hydrological data provided by Benin-Owena River Basin stationed in Auchi Polytechnic were applied for the analysis. The outputs revealed that annual average rainfall of 98.1 mm or more in 75-year; 130.1 mm or more in 50-year out of 100 years. The exceedence probability for a rainfall of 158.1mm is 0.25 with observed rainfall greater than normal. At discharge (10.77 * 10-2 m3/s), the proposed Orle hydropower scheme generated 1.032MW during the peak of wet and 76.6 KW was evaluated during the drying season at (0.80 * 10-2m3/s). The study draws a conclusion that for runoff river scheme at 41.7% flow, the total hydropower potential of 0.676 MW was evaluated.

228-238

Authors: Olawale Olamide, Oyawale Festus Adekunle, Adediran Adeolu Adesoji, Obafemi Akinwale Sunday

The present work investigate the inhibition of Jatropha Stem Extract (JSE) in sea water using mild steel coupons of dimension 5 × 5 × 0.5 cm. The cupons were immersed in test solutions of sea water and varied concentrations of extracts of 0.1g/l to 0.9g/l was used. The functional groups of the compounds was analyzed using an FTIR. The results showed that as the concentration of the extract increases, there was a reduction in the corrosion rates. Furthermore, as the extract concentrations increased from 0.1g/l to 0.4g/l at 48hrs exposure time, the weight loss decreased by 14.3% in the medium. However, the Jatropha Stem Extract was absorbed on the substrate surface to inhibit corrosion, the morphology of phases formed from the scanning Electron Microscopy examination confirmed this trend. Hence, JSE is a good and safe inhibitor in sea water solution. The FT-IR results also indicates the presence of active corrosion inhibitor present in the Jatropha Stem.

249-260

Authors: Farshad Panahizadeh, Navid Bozorgan

Greenhouse gases (GHG) causing global warming and climate change. In the year 2014, 32.3 billion tones CO2 emitted to the atmosphere as the most important greenhouse gas. According to the statistics, a significant portion of this amount is related to electricity demand of air conditioning systems, for producing a one ton of refrigeration in HVAC air cooled or water cooled systems respectively 1026 and 764 grams GHG emitted in the atmosphere. Therefore, air conditioning systems have an important role in the global warming and climate change. By increasing the COP of air conditioning systems the electricity demand of them reduced. One strategy for increasing the COP of air conditioning systems is using nanorefrigerants. In the present study, a comprehensive information is given regarding to use nanorefrigerants in air conditioning systems according to the theoretical, CFD and experimental review of the recent literature. This paper gives assistance to designers of air conditioning systems in their future efforts for selecting refrigerant for their systems.

273-282

Authors: Svilen Rachev, Cornelia Anghel Drugarin, Konstantinos Karakoulidis, Ivaylo Dimitrov, Lyubomir Dimitrov

The dynamic behavior during operation of the high-voltage induction motor electric drive has been studied by means of mathematical model developed. The purpose is to draw out more clearly picture of operation of high-voltage induction motor drives. The system of differential equations has been transformed and solved using suitable software. As a result the values of the energy losses components in the induction motor have been obtained according to different values of supply voltage and factor of inertia. Some of the study results have been presented graphically. An analysis has been made and conclusions from the results obtained have been done.

291-304

Authors: Uday Singh Rajput, Neetu Kanaujia

Combined effects of Hall current and chemical reaction on unsteady MHD flow past a vertical plate with constant wall temperature and mass diffusion is studied here. The fluid considered is electrically conducting and heat generating. The Laplace transform technique has been used to find the solutions for the velocity and Skin friction. The velocity profile, temperature and mass diffusion have been studied for different parameters like Schmidt number, Hall parameter, magnetic parameter, chemical reaction parameter, mass Grashof number, thermal Grashof number, Prandtl number, and time. The effect of parameters is shown graphically, and the values of the skin-friction have been tabulated.

320-328

Authors: Ioan Ruja, Elisabeta Spunei, Monica Roșu

The paper presents the results of the scientific investigations performed on an Otto engine. One conducted surveys on the analytic and experimental modelling of the internal combustion engine, considered as automated system element. The results of the analytical study are concretised in the mathematical model of the engine, expressed in the operational. The experimental results are concretised in the indicial response in rotating speed, as well as in the determination of the constants of interest. The investigation methods used in conducting the survey were: experimental identification based on the indicial response of the engine and the analytical identification based on the mathematical models of diverse engine subsystems.

337-346

Authors: Elisabeta Spunei, Ion Piroi, Florina Piroi

We analyse in this work three outdoor lighting systems using three types of light sources, in order to determine their performance with respect to outdoor lighting restrictions. The study in this work contributes to gaining insights on how to increase the outdoor lighting systems’ energy efficiency. We analyse two LED source types and one sodium fumes light source type, which illuminates various sections on a street in Reşiţa, Romania. Upon analysing and processing the data, we establish the performances of each of the three lighting sources, whether they respect the imposed standards, and which one is the best lighting source to choose. This work shows the necessity of field measurements regarding the lighting system efficiency before the acquirement of a specific system type.

357-368

Authors: Ion Vela, Daniel Gheorghe Vela, Monica Roşu

The paper presents aspects related to the evolution of industry at Reşiţa, where in 1771 they put the first high furnace into exploitation. Along time these furnaces have undergone continuous improvements and modernisations, and in 1868 the Reşiţa Works started producing steel and two Bessemer converters were mounted. Due to the continual operation and enhancement, in conditions of „permanent fire”, Reşiţa acquired the name of Romania’s „FIRE CITADEL”. In parallel machinebuilding industry also developed at Reşiţa. The increase of the necessary quality products imposed the development of scientific research and of the specialised schools and colleges.

378-392

Authors: Olotu Yahaya, Oyati Edith Nwabuogo

The scientific evidence of climate change as a result of greenhouse gas emissions which causes ozone layer depletion is becoming increasingly obvious and clear. Findings revealed that energy from the fossil fuel is the major source of greenhouse emission which destroys the environment and makes it unhealthy for living beings. In Nigeria, conventional energy (oil and gas) with gas flaring has the highest percentage of 52% and liquid fuel of 32% of carbon dioxide (CO2) respectively. This sector contributes revenue of over 70% to Nigeria’s economy and generates an average total 21.8% of greenhouse gas emission. In Nigeria, there is a much more potential for share renewables with 15.4% of total energy production and 8.6 % of energy consumption. In reality with global environmental concern, Nigeria’s carbon dioxide emissions have increased with energy production and consumption. The Integrated Renewable Energy Master Plan of 2008 projects a 26.7% renewable energy contribution to the Nigeria’s energy use and this is expected to reduce CO2 and greenhouse gas emissions at 38% by2025. Nigeria has not been playing significant role by reducing emissions of greenhouse gases. This paper highlights Nigeria’s climate change situation and penetration requirements for various renewable energy deployments as mitigating instrument for climate change towards healthy and productive environment.