Analele Universitatii

18-32

Authors: Basil Akinnuli, Olayinka Oluwole Agboola, Peter Pelumi Ikubanni

An Unmanned Surveillance Aerial Vehicle (USAV) is an air vehicle which is largely used for surveillance, monitoring, reconnaissance, data relay, and data collection or to enter an area which is not safe for human. This study documents the development and evaluation of a low cost, short range unmanned aerial vehicle to monitor a fixed operational urban area. Aerodynamic principles were employed to develop a better concept through reasonable design considerations and assumptions. The design was then modeled using National Aeronautics and Space Administration (NASA) Vehicle Sketch Pad (VSP). Analysis of aerodynamic properties of the wing airfoil section, lift and drag analysis of resisting surfaces, stability in flight were carried out with the aid of Computational Fluid dynamics software (JAVA FOIL). Ultimately, in achieving the goal of this study, the design concept was supported by the fabrication of a flying prototype.

41-46

Authors: Cornelia Victoria Anghel Drugarin, Mihaela Dorica Stroia

Computer-Aided Manufacturing (CAM) assumes to use dedicated soft-ware for controlling machine tools and similar devices in the process of workpieces manufacturing. CAM is, in fact, an application technology that uses computer software and machinery to simplify and automate manufacturing processes. CAM is the inheritor of computer-aided engi-neering (CAE) and is often used conjunctively with computer-aided de-sign (CAD). Advanced CAM solutions are forthcoming and have a large coverage, from discrete systems to multi-CAD 3D domain. CAM does not supersede the necessity of human factor intervention, as produc-tion engineers, programmers or operators, but intercedes the knowl-edge of experimented manufacturing engineers by using performant devices, while enhancing the competences of new professionals by having access to latest modern equipment. CAM runs along with CNC machines. The purpose of CAM-CNC system is to reduce as much as possible the intervention of human factor, thus reducing human error. The present paper follows to highlight the advantages of CAM-CNC sys-tem on a 3D workpiece manufacturing.

55-66

Authors: Bogdan Clavac, Zoltan-Iosif Korka

Gears are extensively used in many applications, such as: automotive, drive trains, industrial gearboxes and machine tools. They are designed to transmit power and rotational motion from the input shaft to the output shaft. In the design process of a gearbox, factors such as: load capacity, size, lifetime or manufacturing cost are often taken into consideration. However, precise measures of efficiency are frequently forgotten issues in the design process. Such shortfalls relate to oil churning, wind age, oil squeezing during gear mesh, or the friction processes at the level of the gear pairs, seals and bearings. This paper presents a calculation method used to determine the efficiency of helical gear transmissions. The method was validated by experimental measurements. Finally, influence factors on the gearbox efficiency, such astransmitted load and operating speed are presented.

72-79

Authors: Ioan Dragoş Deaconu, Alexandru Anghel, Aurel Ionuţ Chirilă, Valentin Năvrăpescu

This article presents experimental data on Light Emitting Diode (LED) lamps of low wattage that are commonly found both in commercial and residential applications. A comparison with the existing regulations is performed. The measurements are performed using power and energy quality analyzer intended also for avionic and military systems

88-100

Authors: Maciej Dutkiewicz

The detailed aim of the study is to determine the distribution of flow velocity, turbulence, the frequency of detaching vortices. These parameters are measured for conductor installed in the wind tunnel and it models the overhead transmission line in wind flow conditions. Knowledge of these parameters are very important from the perspective of response of the conductor on wind load excitations generating the vibrations of the system and the results can be useful in the design process. Measurements are made for constant air velocity, fixed turbulence at the inlet of the tunnel.

113-120

Authors: Tudorel Ene, Dorian Nedelcu

This paper presents the structural analysis of a classic constructive variant of a bridge deck with a railroad, designed in accordance with SR 1911. The analysis was done using the SolidWorks Simulation software and focused only on the deck, without taking the pillars into consideration. The deck was loaded with the weight equivalent of a railroad car. A study of static analysis was conducted after the 3D structure of the deck was generated, in order to determine the distribution of tension and distortion on the deck elements, the areas with the greatest tension and distortion and solutions to minimize them.

129-141

Authors: Clement Oluwole Folorunso, Timothy Ohiosimuan Aigboje

This research work establishes the effects of CO2 on users’ comfort in residential building with specific residential neighborhood in Bawak Sabo as the study area. There is an existing complaint of sneezing, tiredness, sweating and headache at dawn from resident of this neighborhood documented in a medical report of a medical hospital within the community. The research is set to investigate the cause of these problems. The methodology adopted was the combination of experimental- field survey and review of existing literature. Measurement of CO2 concentration was conducted in a given 10% sample population (cases). Measurement was taken in tenement and bungalow accommodation of varied room sizes (9.0m2 and 12.6 m2 floor area), population (one to two occupants per room) and window opening adjustment. Measurements were taken 8 hours day time and twilight with varied user activity and ventilation rate respectively. The results show that CO2 concentration was higher in rooms with larger numbers of persons. CO2 concentration was closely related to room size and density and increased rapidly when doors and windows were locked. Elevated carbondixoide was low in bungalow accommodation with more numbers of window openings in comparison with tenement accommodation. Differential levels of CO2 concentration have negative impacts on the users’ in ways such as shortness of breath, sneezing sweating and increased breath rate among others. It was concluded that CO2 concentration was responsible for the reported discomfort experienced by Bawak-Sabo residents.

149-156

Authors: Draghiţa Ianici, Sava Ianici

The paper presents a detailed study of the gearing processes in the two stages of the double harmonic transmission. To highlight the graphics of the relative motion of the conjugates teeth it was developed an original calculation program, written in Visual Basic. By running the calculation program, the relative successive positions of the conjugate teeth were viewed and the basic parameters of the gearing were established: the angle profile (a), the tooth height (h) and the size of the deformation of the flexible toothed wheel (w0).

163-168

Authors: Sava Ianici, Draghiţa Ianici

The paper presents a study of the strains and stress state in the flexible toothed wheel of a radial harmonic transmission, in the case of its deformation by a 2 roller mechanical wave generator. Dynamic research has pursued the numerical simulation of a flexible toothed wheel, in the form of a long circular tube, open at one end, by using the finite element method and using the SolidWorks Simulation program in elastic range.

184-194

Authors: Virgil Maier, Sorin G. Pavel, Horia G. Beleiu, Constantin S. Pică

In the paper, five global and synthetic sizes are proposed for the earth grounding, predestined to represent distinguishing criteria and to justify the chosen solution: the footprint area, the dispersion surface, the metal part mass and the earth grounding volume have technical character, while the investment cost has an economic nature. Resuming the sizing relationships of earth grounding gives the opportunity to develop a new nomogram for calculating the dissipation resistance of a single vertical earth grounding as well as highlighting the quality and quantity of its specific dependencies. Processed forms are presented in the paper as well for the use coefficients of the multiple earth grounding, defining the determination of the electrode number which minimizes at least one of the proposed global sizes as the main target of the study

205-210

Authors: Calin-Octavian Miclosina, Zoltan-Iosif Korka, Vasile Cojocaru

The paper presents a 6-DOF industrial robot and the driving system of its base translational joint. By imposing certain positions of the translational joint and determining the durations in which these positions are reached, average speed is computed. The paper shows how the clearances influence the average speed, depending on the displacement value.

219-224

Authors: Ion-Cornel Mituletu, Nicoleta Gillich, Emilian Stanciu, Codrin-Nistor Nitescu

Nowadays high-speed microcontrollers are employed to accomplish many applications in different domains, due to their flexible characteristics and structures. In this paper, the microcontroller algorithm performs a fast time-frequency analysis by discrete Fourier transform (DFT) on variable time portions of the vibration signal. System can be easily customized so that a spectrum with variable range and density is achieved. Also, the real-time microcontroller based system (R-TMBS) has been thought as a stand-alone system as well as to be included in a more complex system, which can function in closed-loop, when the system feedback is obtained via R-TMBS.

235-246

Authors: Marian-Dumitru Nedeloni, Eugen Birtărescu, Lidia Nedeloni, Aurel Băra, Adrian Pellac

This paper presents some information regarding the hydraulic turbines respectively the experimental results on cavitation erosion behavior of a 13Cr-4Ni stainless steel used to manufacture the components exposed to water of the Francis, Kaplan and Pelton hydraulic turbines. So, the presented experimental results of this paper highlight the good cavitation erosion resistance of the analyzed 13Cr-4Ni stainless steel.

257-266

Authors: Arina Negoiţescu, Adriana Tokar, Dan Negoiţescu, Codruta Hamat

For an energy-efficient future, the EU needs to step up its efforts to maximize energy savings. In this context, the paper addresses the steps needed to establish energy efficiency measures and proposes effective measures to reduce consumption by recovering large amounts of energy lost to industrial consumers. The points with the highest recoverable energy potential have been identified and it is proposed to install the heat recovery systems on the flue gas exhaust circuits and polluted air from Industrial Technological Equipment (ITE) such as dyeing/ drying cabins (DDC). Therefore, whenever possible and as small as energy saving, energy recovery solutions at any level, but especially at local level, need to be applied. In conclusion, by concentrating all the energy-saving efforts that are still being wasted, Europe can contribute, by saving energy, to ensuring a sustainable energy future.

279-286

Authors: Codrin-Nistor Nitescu, Zoltan-Iosif Korka, Gilbert-Rainer Gillich

This paper presents an experimental procedure to assess damages of welded beams, the weld being transversal to the longitudinal beam axis. It consists of comparing the natural frequencies in intact and damaged state, calculating the frequency shift due to damage and weigh the shifts against patterns derived a priori.

302-311

Authors: Oyati E.N., Stephen A.O.

It is obvious that we are living in a noise-polluted environment. This pollution has been linked to a number of health related ailments such as depression, anger, weak concentration and hearing defects. Growing global population, increase in technological advancement and some human activities are major causes of this noise-related pollution. This study investigates environmental effects of noise pollution on man for possible mitigation strategies. Sound level meter (SLM) was used to obtain the level of noise pollution in decibel (dB). Selected noisegenerating centres were used such as mosques, churches, markets, schools and household appliance-loudspeakers. Noise pollution variables (NPV) were mathematically-modelled and analysed using statistical metrics. Sound powers (SP), total power level (SPL) and total sound pressure level (SPL) were computed using empirical relationship. Reference power (RF) and pressure (RFP) values of 10-12 watt and 2.0 * 10-5 N/M2 were computed. 230.65dB and 106.3 dB values of SWL were obtained. These values indicate serious health hazard because it is far above acceptable standard. The output of the resultant mathematical iterations indicates that the impact of noise pollution is a cumulative function of population increase, human activity and technological advancement at 1% and 5% level of significance. Generally, obtained results showed that the impacts noise pollution on man and his entire environment are obviously on the negative side. Hence, possible mitigation measures such as noise pollution regulatory policy enactment and design of noise absorbing structures are strongly recommended

320-328

Authors: Farshad Panahizadeh, Mohammed Hasnat, Ashkan Ghafouri

The main objective of the present numerical study is to investigate the transient heat transfer in one kind of all-purpose longitudinal fin with the triangular profile. The lateral surface of the concerned fin and the tip of it are subjected to general situations included heat flux at the base and insulation on the tip. For this study developed a one dimensional in house code written by Fortran 90 programming language by using finite difference method with an implicit scheme in unsteady state condition. Generally, the result of this study in time variation state after 700 seconds is steady. The results also show the fin efficiency by increasing the time of study decreases due to a reduction in the total heat transfer which is happened in the fin. The grid independence study shows that for the number of nodes greater than 20 the result will not be changed and same as before. Finally, the result of Fortran code verified by commercial CFD code which relies on finite difference method and it was shown have a consistent agreement.

333-337

Authors: Silviu Mihai Petrişor, Raul Alexandru Icleanu

The present paper highlights the way of developing on a scale of 1:1 a microwave generating device, a prototype that is designed for being used in the special missions assigned to military engineer specialists to combat terrorism. This device, used as a psychotronic weapon, can remotely neutralize various brain centers, thus preventing the terrorist action to be carried out by the person concerned. The paper presents in detail the organological construction and the operation of this device, also pointing out the advantages, the scientific novelty and the originality of the use of such a prototype in counterterrorist actions.

352-355

Authors: Marius Romocea

Enhancing the machines’ technical and technological performance through constructive improvements that allow for the automation of orders, contributes to the increasing of the production capacity of the system and for maintaining an optimal level of product costs. In order to achieve these goals, it is necessary to organize the maintenance work well, in order to quickly diagnose the malfunctions and to shorten the repair time. Given the scale of the phenomena, this paper seeks to answer two questions, namely: how will be the maintenance in future and also how to prepare this activity.

372-379

Authors: Nicolae–Doru Stănescu, Nicolae Pandrea

This paper is a complementary one for our previous paper [25]. The collision of the ellipsoid is considered to take place with the main planes of the reference system. In our simulation we obtain the following results: no collision, collision with a single plane, simultaneous collision with two planes, simultaneous collision with the all three planes, and collision for a longer time with one or more planes

386-389

Authors: Fanel Dorel Scheaua

The construction sector experienced a constant evolution over time, so that today structures can be made to withstand earthquakes of considerable magnitude. This can be achieved by using various methods to counteract the direct earthquake destructive action on the construction. The methods consist of using insulation systems or earthquake energy dissipation devices that have occurred in time, being in constant development and improvement. In this paper it is presented a model of a hydraulic dissipation device as an assembly of a linear motor with fluid, which can be mounted to the structural frame of a bridge, in order to take some of the earthquake energy when it occurs, so that the bridge superstructure is protected against from high magnitude damages.

396-401

Authors: Fanel Dorel Scheaua

Today there are multiple solutions intended to avoid the earthquake damaging effects on building structures. There are methods based on the use of special mechanical systems attached directly to the structure's resistance frames, by means of which an improved building behavior is achieved during the earthquake. The systems used work on the principle of structure base isolation based on the dry friction force (Coulomb friction). Some constructive types of these isolation systems patterns are described in this paper

411-417

Authors: Ioan Virca, Dănuţ Eugeniu Moşteanu, Dorel Badea

Within a wide range of theoretical and experimental research, the possibility of realizing a new method of superficial treatment of materials made of metallic powders and the validation of the results obtained after the treatments were carried out with gas discharge lamps. The structural transformations carried out in the superficial layer of the pieces made of metal powders used in the experiments led to a statistical analysis of the results obtained in this article. Thus, with the TREND statistical function of Excel program, the evolution of the changes in roughness was determined, depending on the variable parameters of the treatment process. The verification was performed with the ZTEST function by making assumptions about the average values of selection reported against the critical value of the test. The results were interpreted on the basis of the phenomena and processes that occur at superficial level at the interaction of the radiation with the non-homogeneous layer specific to the pieces made by the aggregation of powders, consisting of granules and pores. The conclusions recommend the optimal treatment regimes in order to obtain the maximum efficiency of the action of the optical radiation pulses emitted by the gas discharge lamps on the surface of the metal powders.

429-438

Authors: Aw Nien Wei, Md Azree Othuman Mydin

The construction industry is the main economic support for all countries around the world in which continually adapting to meet competitive challenges around the global market. Nevertheless, the construction project is becoming much more complex and difficult to manage. This is because the construction project involves a large number of stakeholder, for example, the consultant companies, architects, engineers, building surveyors and quantity surveyors. The technology currently used in the construction industry is the AutoCAD (Automatic computeraided design). AutoCAD is a commercial software application for 2D and 3D computer-aided design (CAD) and drafting develop by Autodesk. Generally, all the drawing design from Autocad will be exchanged among the stakeholder in the form of paper. Information exchanged among them mostly involves a lot of documents and drawings. This practice creates errors because of documents and drawings are mostly in a paper-based format that is not properly managed which results in miscommunication among them. Having wrong information in the construction process could hinder the productivity of projects because in a construction project information is one of the important construction materials. Building Information Modeling (BIM) is one of the newly software in the architecture, engineering, and construction (AEC) industries to ensure all parties receive the right information. BIM technology is also an intelligent model of a building constructed digitally in the way of 3D. The software will generate model containing the information needed to support the construction, fabrication, and procurement activities that needed to realize the building. This paper will discuss on potential and benefits of BIM during pre-construction stage, construction stage and during post construction stage.