Analele Universităţii
"Eftimie Murgu"
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Fascicula de Inginerie

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Anul XIX (2012), Nr. 1

TABLE OF CONTENTS

ARTICLES

The Influence of the Wheel Conicity and the Creep Force Coefficients to the Hunting Motion Stability of a Bogie with Independently Rotating Wheelsets
Daniel Baldovin , Simona Baldovin

The hunting motion of railway vehicles is a coupled lateral and yaw self-oscillatory motion which is largely determined by wheel–rail contact geometry. The stability of this motion is an important dynamic problem, depends of the railway vehicles speed and determines the maximum operating speed of the vehicles. To improve the stability performances, without increasing the rail-wheel interaction forces above safety limits, elastic joints and dissipative devices are used to connect the wheelset to the bogie frame. In this paper is studied the influence of the wheel conicity and the creep force coefficients to the hunting motion stability of a dynamical system with 10 DOF representing a bogie with independently rotating wheelsets

Keywords: Hunting motion, critical speed, bogie, creep, conicity

Mixed Solutions of Electrical Energy Storage
Cristian Paul Chioncel, Petru Chioncel, Babescu Marius

The paper presents electrical energy storage solutions using electric batteries and supercapacitors powered from photovoltaic solar modules, with possibilities of application in electric and hybrid vehicles. The future development of electric cars depends largely on electrical energy storage solutions that should provide a higher range of road and operating parameters comparable to those equipped with internal combustion engines, that eliminate pollution.

Keywords: supercapacitors, electric battery, photovoltaic modules,fuel cells

Fuel Cell / electrolyser, Solar Photovoltaic Powered
Cristian Paul Chioncel, Babescu Marius, Petru Chioncel

The paper presents experimental obtained results in the operation of electrolyzer powered by solar photovoltaic modules, for the water electrolysis and with the obtained hydrogen and oxygen proceeds to the operation in fuel cell mode, type PEM. The main operating parameters and conditions to optimize the energy conversion on the solar-hydrogen-electricity cycle are highlighted, so that those are comparable or superior to conventional cycles.

Keywords: solar photovoltaic module, electrolyser, fuel cell

Mechanical Self-shrinkage of Artillery Barrels
Ioan Ciorba

Objective of this paper is to define what self-shrink artillery barrel is. She is considered to be a compound barrel like as a thick-walled tube (k>2), in his wall being introduced a state of stress and strain using specific technological proceeds. This type of treatment is aimed to increase the artillery barrel load capacity and wear resistance in operation. The experimental part was realized using an industrial plant at Mechanical Factory of Resita. This part presents a comparative study between mechanical self-shrinkage on artillery head barrel, first using a mandrel and seconds a ball.

Keywords: mechanical self-shrinkage, degree of self-shrinkage, barrels, stress, strain

Design Principles for Earthquake Resistant Buildings and Post Earthquake Study by Structural Engineering Perspectives
N.K. Dhapekar, S.M. Awatade, N.N. Bhaiswar, K.S. Shelke, M.D. Mehere

Two major earthquakes hit India in last eight years. The first in Killari (Latur) Maharashtra on 30th September 1993(Magnitude 6.4,deaths about 10,000) and the second recently at Bhuj Gujrat on 26th January 2001(Magnitude 8.1,deaths more than 35000).In USA two earthquakes took place one in California on 17th January 1994(Magnitude 6.6,deaths 57) and second in Ciatel near Canada on 1st March 2001(Magnitude 6.8,death 1).It shows clearly that the damage to structures and loss of life is more in developing countries like India as compared to developed countries like USA,Japan etc. This is due to lack of awareness in adopting Indian Standard codal provisions for earthquake resistant design. It is highly expensive to construct structure 100% earthquake proof. This paper aims to highlight design principles for earthquake resistant buildings which should be compulsorily adopted during the construction. In this paper, post earthquake effects on buildings from structural point of view are also highlighted.

Keywords: post earthquake, building, structural, engineering

Geometric Filtering Effect of Vertical Vibrations in Railway Vehicles
Mădălina Dumitriu

The paper herein examines the geometric filtering effect coming from the axle base of a railway vehicle upon the vertical vibrations behavior, due to the random irregularities of the track. For this purpose, the complete model of a two-level suspension and flexible carbody vehicle has been taken into account. Following the modal analysis, the movement equations have been treated in an original manner and brought to a structure that points out at the symmetrical and anti-symmetrical decoupled movements of vehicle and their excitation modes. There has been shown that the geometric filtering has a selective behavior in decreasing the level of vibrations, and its contribution is affected by the axle base magnitude, rolling speed and frequency range.

Keywords: railway vehicle, vertical vibrations, geometric filtering

Dynamic Behavior of a Friction Pendulum with Elastomeric Layer
Gilbert-Rainer Gillich, Claudiu Mirel Iavornic

Transient dynamic characteristics of a friction pendulum can be determined using experimental ways. Nowadays, numerical simulation techniques allow obtaining these characteristics using mathematical models. The express advantage is represented by almost unlimited possibilities to extract and quantified in the regime of "post processing" regarding the results. In terms of efficiency this means increased performance regarding the research and product development.

Keywords: analysis, finite element method, transient

Innovative Elastomeric Element for Earthquake Isolation
Vasile Iancu, Claudiu Mirel Iavornic

A modern tool to study the behavior of elastomeric elements for earthquake isolation is the Finite Element Method. The results of the simulations obtained in this way provide a large series of data about the behavior of the elastomeric elements under different types of loads and help in taking right decisions regarding geometrical optimizations needed for improve such kind of devices.

Keywords: elastomeric isolation systems, earthquake, safety, finite element method

Life Cycle Influence on the Policy of Product Development
Sava Ianici

It is well known that "product life on the market" is the main reason for developing and improving of product. Therefore all producers tend to provide as long as possible life cycle of their products. The author of this paper wanted to indicate the basic principles of defining of life cycle of products. The paper analyses technical lifetime, but also economical, ecological and even, fashion lifetime, because they are also, important, and in certain cases even crucial, for bringing final decision about treating the product. Besides, a review of usual possibilities of increasing life cycle of products in machine industry is presented.

Keywords: life cycle, product development, product policy

Computation of Water-Stress Ratio in Western Nigeria
Philipa Omamhe Idogho, Olotu Yahaya

An increasing world population exerts a continually growing demand on usable freshwater resources. Access to water plays a key role in development; it supports human life in direct consumption, agricultural uses and industrial activities. Time and drudgery involved to access safe drinking water resulted to loss of human resources and capital, thus affecting nearly every household life. This paper focuses on the determination of water-stressed ratio using Integrated Water Measurement Tool (IWMT). Structured simple time analysis and Adjusted composite index approaches were employed to compute (IWMT) values in all the sampled areas. Variables such as access to safe water coverage, water availability and use of water were considered. IWMT values from the two approaches show that Ese-Odo is the most water-scarce region with least IWMT values of 14.1 (Adjusted composite index: ACI) and highest value of 2.6 minsl-1 (Structured simple time analysis: SSA), while Owo, Ondo-West and Ose local government areas experience fair distribution of protected water supply with IWMT values of 1.05 minsl-1, 20.8; 1.00 minsl-1, 17.2; and 0.55 minsl-1, 16.9 respectively. The results obtained indicate that constructive investments in water and sanitation would reduce proportion of household income spent in sourcing for safe drinking water, prevention of water-related diseases and in turn improves productivity. However, this paper concludes that top-down technical approach must be balanced with a bottom-up mechanism in order to derive realistic systems to prevent persistent water scarcity, shortage and to draw realistic adaption measures..

Keywords: IWMT, index, water stress, safe water, access, waterscarce, uses, household, ACI, SSA, ratio

Evaluation of Cylinder Volume Estimation Methods for In-Cylinder Pressure Trace Analysis
Adrian Irimescu

In-cylinder pressure trace analysis is an important investigation tool frequently employed in the study of internal combustion engines. While technical data is usually available for experimental engines, in some cases measurements are performed on automotive engines for which only the most basic geometry features are available. Therefore, several authors aimed to determine the cylinder volume and length of the connecting rod by other methods than direct measurement. This study performs an evaluation of two such methods. The most appropriate way was found to be the estimation of connecting rod length based on general engine category as opposed to the use of an equation that predicts cylinder volume with good accuracy around top dead centre for most geometries.

Keywords: in-cylinder pressure trace analysis, piston engines, connecting rod length, cylinder volume

Comparative Study of Reducing the Vibration Level of a Cylindrical Gear Transmissions by Increasing the Manufacturing Precision of the Gears, Respective by Applying of Fluoropolymer Coating on the Gear Teeth
Zoltan Korka, Virgil Dan Cărămidaru

The current trend in the construction of gearboxes, regarding the speed increase, favors the increase of the dynamic loads and, consequentially of the vibration level. Therefore, the vibration reduction of gear transmissions finds a growing interest, representing an element of fight against environmental pollution.

Keywords: gearbox, vibration, flouropolymer coating

Microalloying with Cd of Antifriction Sn-Sb-Cu Alloys
Cinca Ionel Lupinca, Constantin Marta, Attila Szabo

In the case of bimetallic sliding linings with superior technological characteristics, the use of an antifriction ally is imposed an alloy of the type Sn-Sb-Cu, which possesses a high adherence to the steel stand and a high durability in exploitation. For this reason we use the microalloying of the antifriction alloy with cadmium. The microalloying with Cd of antifriction alloys Sn-Sb-Cu determines an increase of the adhesion property of the antifriction alloy on the steel stand. The steel stand is previously subjected to a process of degreasing with ZnCl2 and washing so that is can later be subjected to a thermal-chemical treatment of tinning.

Keywords: rotation bearings, microalloying antifriction alloys

Contact Pressure Analysis on Radial Ball Bearings
Tiberiu Mănescu jr., Gilbert-Rainer Gillich

The paper analyze the value of the maximum Hertzian pressures developed at the contact between 12,7 mm bearing balls, the upper ring, the lower ring and the rolling track. We verified three types of ball bearings with the ball number equal with 8, 10 and 12, at a maximum force F, constant on the most strained ball, with values between 1100 N and 1500 N, at nine loading cycles which add 50 units per cycle.

Keywords: radial bearing, axial bearing, contact pressure, bearing ball

Categorization of General Problems and Defects in Historical Building
Rozliani Mansor, Md Azree Othuman Mydin, Mazran Ismail, Wan Mariah Wan Harun

Generally, there are numerous defects and problems which are common to historical building parts such as roofs, walls, floor, ceilings, toilets, door and window. Ever since the building boom of the 1970s, many of Malaysia's historic building had been demolished. Current large scale urban development continues to threaten prewar buildings, while other historic buildings are merely declining owing to the age, abandon and high cost of maintenance. The above observation is the case with current situations found in the buildings designated in this study. Basically, it is very important to recognize and diagnose the defect that occurs at various locations with deferent types of causes and symptoms. Generally all existing structures of historical buildings are from stone, brickwork, plaster and timber. The problem, weakening and failure of the building are due to old age which gives rise to defects and faulty formation that had occurred since it was erected and aggravated by subsequent sloppy repairs or total ignorance. This paper will presents some general problems and defects occurred in historical building.

Keywords: building defects, historical building, building problems, common defects

Classification of Inheritance Shop Houses in George Town, Penang - UNESCO World Heritage Site
Rozliani Mansor, Md Azree Othuman Mydin, Norazmawati Md Sani @ Abd Rahim, Ruhizal Roosli, Hasnanywati Hassan

Shop house is an urban terrace house attribute of Asian towns from the 18th century which usually integrates a shop or business premise on the ground floor whilst the family dwells on the upper level, providing both ease and safety. The shop house might also be used entirely as dwelling quarters. Shop houses are constructed in rows and each row is arranged in blocks enclosed within a grid of main roads, back lanes and side roads. A shop house is usually two or three storeys high and is long and narrow, sharing a party wall with neighbours on either side. The Penang shop house is a ideal paradigm of a green building, using materials that are locally obtainable such as lime, clay stone and timber and suited to local geology and weather conditions. Shop houses also possessing architectural characteristics such as air vents and air-well that assist with natural ventilation and cooling. This paper will discuss categories and styles of the shop houses in historic city of George Town which can be divided into nine major groups.

Keywords: shop house, George Town, UNESCO, heritage, historic city

The Influence of the Weight Loss upon Natural Frequency Changes in Case of Severe Defects
Petru Florin Minda, Claudiu Mirel Iavornic, Gilbert-Rainer Gillich

The paper presents a research regarding the use of a "virtual" material in order to compensate the loss of mass in the case of the damaged beam. Because of the loss of mass, the frequency of the beam suffer an increase over the natural frequency of the undamaged beam and so we have proposed the use of this material, having the same density with the density of the beam, in the gap left by damage.

Keywords: scantilever beam, damage, weight loss compensation, frequencies

Mechanical, Thermal and Functional Properties of Green Lightweight Foamcrete
Md Azree Othuman Mydin, Norizal Md Noordin

In recent times, the construction industry has revealed noteworthy attention in the use of lightweight foamcrete as a building material due to its many favourable characteristics such as lighter weight, easy to fabricate, durable and cost effective. Foamcrete is a material consisting of Portland cement paste or cement filler matrix (mortar) with a homogeneous pore structure created by introducing air in the form of small bubbles. With a proper control in dosage of foam and methods of production, a wide range of densities (400 - 1600 kg/m3) of foamcrete can be produced thus providing flexibility for application such as structural elements, partition, insulating materials and filling grades. Foamcrete has so far been applied primarily as a filler material in civil engineering works. However, its good thermal and acoustic performance indicates its strong potential as a material in building construction. The focus of this paper is to classify literature on foamcrete in terms of its mechanical, thermal and functional properties.

Keywords: foamed concrete, thermal properties, mechanical properties, functional properties, lightweight concrete

Elastic Modulus of Foamcrete in Compression and Bending at Elevated Temperatures
Md Azree Othuman Mydin

This paper will presents the experimental results that have been performed to examine and characterize the mechanical properties of foamcrete at elevated temperatures. Foamcrete of 650 and 1000 kg/m3 density were cast and tested under compression and bending. The tests were done at room temperature, 100, 200, 300, 400, 500, and 600 degree C. The results of this study consistently demonstrated that the loss in stiffness for cement based material like foamcrete at elevated temperatures occurs predominantly after about 95 degree C, regardless of density. This indicates that the primary mechanism causing stiffness degradation is microcracking, which occurs as water expands and evaporates from the porous body. As expected, reducing the density of LFC reduces its strength and stiffness. However, for LFC of different densities, the normalised strength-temperature and stiffnesstemperature relationships are very similar.

Keywords: foamed concrete, compressive strength, flexural strength, elevated temperature, modulus of elasticity

Building Maintenance Management System for Heritage Museum
Md Azree Othuman Mydin, Siti Hajar Ismail, Norhidayah Md Ulang

An investment in the building maintenance aspect is massive throughout the world. In most of the countries, it signifies approximately 50% of the entire revenue of the construction industry. The value of buildings depends on the eminence of the maintenance invested in them. Maintenance management engages obtaining utmost advantage from the investment made on the maintenance activities. At the moment, maintenance in buildings in Malaysia is on the increase in spite of size, category, location, and ownership. This study focuses on Building Maintenance Management System for Heritage Museum, which consists of two case studies in Penang State Museum and Art Gallery, Malaysia and Museum of Perak, Malaysia. The aim of this study is to propose methods to improve the maintenance management system for heritage museum. From the results, the common problem occurs during the implementation for the maintenance of each building is the budget for the maintenance and worker's skill. The department of each museum must have their own maintenance unit to keep an eye on the maintenance activities for their buildings in order to improve the maintenance management system in their building.

Keywords: maintenance management, heritage building, museum, art gallery

Condition and Defect Surveys on Penang Heritage Centre: A Case Study on Georgetown World Heritage Building
Masyatul Husna Othman, Md Azree Othuman Mydin

Condition and defect surveys are process which appropriate experts investigates the existing condition of a building, carry out necessary tasks, evaluate the data collected, make the recommendations professionally about the remedial and predict performance of the building. This paper focuses on condition and defect surveys on Penang Heritage Centre, Malaysia. This building is listed as one of the buildings under Georgetown World Heritage Site. Penang Heritage Trust is a heritage shop house designed with Southern Chinese Eclectic Style. It has Chinese, European and Indian style influence. Chinese style influence on the carved timber door, air vents, gable and end, air-well and etc. While, European and Indian influences can be seen from the design of the louvered shutters and U/V-shaped terracotta roof tiles.

Keywords: eBuilding Survey, Inspection, Building Defects, Building Failures, Remedy

Online Monitoring of the Air Gap for Large Synchronous Hydrogenerators with the Purpose to Prevent some Operating Troubles
Valentin Nedelea, Ladislau Augustinov, Gheorghe Liuba

This paper refers to the online monitoring of the air gap for large synchronous hydrogenerators by tracking down in time some significant modifications of the air gap with the purpose to prevent some operating troubles determined by unpermitted variations of the air gap.

Keywords: synchronous hydrogenerator, air gap monitoring, measurement fixed coil, rotor, stator, electromotive voltage.

Air Compressor Driving with Synchronous Motors at Optimal Parameters
Valentin Nedelea, Ladislau Augustinov

In this paper a method of optimal compensation of the reactive load by the synchronous motors, driving the air compressors, used in mining enterprises is presented, taking into account that in this case, the great majority of the equipment (compresors, pumps, etc.) are generally working a constant load.

Keywords: synchronous motor, air compressors, compensation, reactive load. exciter

Research through Direct and Indirect Cavitation Method for a Aluminum Specimen
Marian-Dumitru Nedeloni, Dorian Nedelcu

This paper aims to obtain comparative results of the cavitation erosion through direct and indirect cavitation method for a type of a soft aluminum. In the paper can be find the stand and the equipment description, the calibration test of a titanium sonotrode, the experimental results and the main conclusions.

Keywords: sonotrode, cavitation erosion, aluminum specimen

Cavitation Erosion Tests Performed by Indirect Vibratory Method on Stainless Steel Welded Samples with Hardened Surface
Marian-Dumitru Nedeloni, Vasile Cojocaru, Relu Ciubotariu Dorian Nedelcu

The paper presents the results of cavitation erosion tests performed on two types of samples. The materials of the samples are frequently used for manufacturing and repairs of the hydro turbines components submitted to cavitation. The first sample was made by welding of an austenitic stainless steel on austenito-feritic base material. The second sample was made similarly with the first but with a martensitic base material. After the welding processes, on both samples was applied a hardening treatment by surface peening. The cavitation erosion tests were performed on vibratory equipment using the indirect method with stationary specimen. The results show a good cavitation erosion resistance on both samples.

Keywords:cavitation erosion, peening, vibratory method, stationary specimen, stainless steel

Calibration Tests of a Sonotrode and Cavitation Erosion Research through Indirect Cavitation Method for a Steel
Marian-Dumitru Nedeloni

This paper content the describe of cavitation erosion stand, especially the ultrasonic generator; the calibration tests of a oxidable steel sonotrode and the experimental results for a specimen also from oxidable steel material tested at cavitation erosion through the indirect cavitation method.

Keywords:ultrasonic generator, sonotrode, indirect cavitation, steel

Solar Storage Tank Insulation Influence on the Solar Systems Efficiency
Negoitescu Arina, Tokar Adriana

For the storage tank of a solar system for domestic hot water production was analyzed the insulation thickness and material influence. To this end, it was considered a private house, occupied by 3 persons, located in zone I of thermal radiation, for which has been simulated the domestic hot water production process. The tank outlet hot water temperature was considered of 45 degree C. For simulation purposes, as insulation materials for the storage tank were taking into account glass wool and polyurethane with various thicknesses. Finally, was carried out the comparative analysis of two types of tanks, in terms of the insulation thickness influence on the solar fraction, annual solar contribution and solar annual productivity. It resulted that polyurethane is the most advantageous from all points of view.

Keywords:aradiation, flat solar panel, storage tank, solar fraction, thermal insulation, temperature, annual productivity, annual supply

On the Mesh Influence upon the Frequency Results Obtained by FEM Simulations
Ionică Negru, Carla Protocsil, Zeno-Iosif Praisach, Gilbert-Rainer Gillich

The paper presents a research performed by the authors, in order to establish the optimal element dimensions for a given beam, so that FEM simulations should offer highest accuracy by minimum time consumption. To achieve this desire, we made FEM simulations with elements of various dimensions for seven cross-section dimensions

Keywords: beam, natural frequency, FEM analysis, mesh, error

Non-Linear Pushover Analysis of Flatslab Building by using SAP2000
K. Soni Priya, T. Durgabhavani, K. Mounika, M. Nageswari, P. Poluraju

Recent earthquakes in which many concrete structures have been severely damaged or collapsed, have indicated the need for evaluating the seismic adequacy of existing buildings. About 60% of the land area of our country is susceptible to damaging levels of seismic hazard. We can't avoid future earthquakes, but preparedness and safe building construction practices can certainly reduce the extent of damage and loss. In order to strengthen and resist the buildings for future earthquakes, some procedures have to be adopted. One of the procedures is the static pushover analysis which is becoming a popular tool for seismic performance evaluation of existing and new structures. By conducting this push over analysis, we can know the weak zones in the structure and then we will decide whether the particular part is retrofitted or rehabilitated according to the requirement. In this paper we are performing the push over analysis on flat slabs by using most common software SAP2000.Many existing flat slab buildings may not have been designed for seismic forces. Hence it is important to study their response under seismic conditions and to evaluate seismic retrofit schemes. But when compared to beam-column connections, flat slabs are becoming popular and gaining importance as they are economica.

Keywords: Pushover analysis, Retrofitting, Rehabilitation, Column jacketing, Response Spectrum, Demand curve, Capacity curve, Plastic hinge

Considerations Regarding the use of Beam Models for Accurate Calculus of Natural Frequencies
Carla Protocsil, Ionică Negru, Zeno-Iosif Praisach, Gilbert-Rainer Gillich

The paper reflects the research performed by the authors, in destined to find out the proper beam model, in concordance with its geometrical characteristics. This knowledge is needed to establish the adequate relations in the difficult process of damage detection. First, we calculated the natural frequencies for two cases: the Euler-Bernoulli model and the Share model. Afterwards, using FEM simulations we determined these frequencies again. Comparison between analytic results and FEM analysis allow seeing which theoretical models best fit for the various investigated cases.

Keywords: beam, natural frequency, FEM analysis, Euler-Bernoulli model, Share model

Finite Element Analysis of a Single-Phase Alternating Current Meter
Mihaela Răduca, Aki Uyetani, Florin Florea, Sorin Florea

The present paper presents the optimal distance between the components of the single-phase alternating current meter. This influence of the space between the coils and the aluminum disc form single-phase alternating current meter is made by using the finite element analysis, ANSYS, which is a modeling and simulating program.

Keywords: single-phase alternating current meter, coil, finite element, meshing, magnetic flux

Use Possibilities for River Sand in Foundry
Rodica Rădulea, Ionel Cincă Lupinca

In this paper the following characteristics are studied: the chemical and mineralogical composition, the granulation and content of leachate component of different types of sands, collected from various fords of running waters in comparison to those coming from known mines and used as such in foundries for the preparation of casting mixtures. The purpose of the study starts from the premises of finding reduction possibilities of costs in part casting, keeping in mind that known deposits from our country contain increasingly reduced quantities of casting sands.

Keywords: degree of uniformity, medium grains, basic fraction

Charpy Impact Test on Polymeric Molded Parts
Alexandra Raicu

The paper presents the Charpy impact tests on the Acrylonitrile- Butadiene-Styrene (ABS) polymeric material parts. The Charpy impact test, also known as the Charpy V-notch test, is a standardized strain rate test which determines the amount of energy absorbed by a material during fracture. This is a typical method described in ASTM Standard D 6110. We use for testing an Instron - Dynatup equipment which have a fully integrated hardware and software package that let us capture load information at very high speed from the impact tests.

Keywords: Charpy test, polymeric material, ABS samples, injection molding

Optimizing Structural Dimensions and Costs of a Synchronous Generator Depending on the Current Blanket
Elisabeta Spunei, Ion Piroi, Florina Piroi

Optimal structural dimensions and reduced costs are current requirements in electrical machines. Such requirements can be fulfilled already in the design phase by establishing optimal parameter and quantities values, such that the objective function is satisfied. The main optimization variable of this work is the current layer, the resulting optimal values and the charts analyzed here are obtained using a specific program for optimal design. This program is based on the classical design of the synchronous generator. Depending on the aimed objectives the program returns the values of the dimensions of interest. Using an optimal design, for the generator in question, costs have decreased with 4.7% compared to the classical design costs.

Keywords: cost, optimal design, current blanket

On the Electromagnetic Stresses Impact on the Synchronous Generator Costs
Elisabeta Spunei, Ion Piroi, Florina Piroi

In line with the nowadays requirements, the synchronous generators must fulfill the technical specifications and their costs should be as low as possible. For this, the electromagnetic stresses, which significantly influence the synchronous generator costs, must have optimal values. The use of optimal designs helps achieve this objective. In this work we show how the current layer A and the air gap magnetic displacement Bδ influence the generator's costs.

Keywords: optimal design, current layer, magnetic displacement

On the Electromagnetic Stress Impact on the Synchronous Generator Structural Dimensions and Efficiency
Elisabeta Spunei, Ion Piroi, Florina Piroi

Structural dimensions as well as the ability to safely operate in often transient processes or short emergency situations are usual customer requirements. These requirements can be fulfilled already in the design phase by careful selection of electromagnetic stress values (current layer, air gap magnetic displacement).This work contributes to finding optimal values for the above mentioned stresses such that customer requirements are fulfilled.

Keywords: criterion, main variable, current layer

Energetic Efficiency Evaluation by Using Ground-Water Heat Pumps
Tokar Adriana, Negoitescu Arina

Romania has significant energy potential from renewable sources, but the potential used is much lower due to technical and functional disadvantages, to economic efficiency, the cost elements and environmental limitations. However, efforts are being made to integrate renewable energy in the national energy system. To promote and encourage private investments for renewable energy utilization, programs have been created in order to access funds needed to implement these technologies. Assessment of such investments was carried out from technical and economical point of view, by analyzing a heat pump using as heat source the solar energy from the ground.

Keywords: heat pump, renewable energy, energetic potential, heating, horizontal collectors, efficiency

Influence of Absorption and Insulation Properties for Phonic Treatment of Public Works Equipment
Ovidiu Vasile, Gilbert-Rainer Gillich,

This study presents the problem of designing, manufacturing and testing of some protective systems made from composite materials which can simultaneously perform the next requirements: noise absorption for middle and high range frequencies, noise insulation for low frequencies, vibration damping in order to avoid noise transmission by structure and finally, modularity and adaptability for using to different types of public works equipment, also for other technological equipment with a high level of noise, vibration and mechanical shocks. Decreasing of sound and vibration global level inside and/or outside the public works equipment’s cabin as well as the reduction the noise pollution or the pollution due to the vibration and mechanical shocks on construction site is an actual matter, especially for the countries –last became members of EU; these countries must harmonize theirs national legislations regarding the environment pollution and the labor protection with the EU Directives. The article presents the experimental data of four composite structures with noise absorption and insulation features and three case studies of global level noise reduction inside the cabin for a vibrating compactor, a crawler excavator and a frontal loader.

Keywords: phonic treatment, composite structures, noise insulation

Factors of Deterioration in Building and the Principles of Repair
Md Azree Othuman Mydin, Mahyuddin Ramli, Hanizam Awang

Anybody who has owned property recognized that buildings are frequently subject to numerous forms of building defect, regularly in the form of dampness, wall cracks or even a water penetration to the building. Even as the cause of the building defect may be instantly noticeable in several cases, in others the cause is not so understandable. Likewise, there may be an apparent root of a defect, but this may not be the whole story, and the root of the problem may in fact lie elsewhere. An exact identification of a building defect necessitates knowledge and familiarity with the design and construction of a building combined with an indulgent of methods of scientific exploration. An accurate cause of a building defect and the form of its appearance must be understood prior to a sensible remedy can be applied. This paper will discuss on the important factors that affecting the deterioration in building and some principles of repair.

Keywords: building deterioration, principles of repair, building diagnosis, building survey, building defects

Over-And Understeer Behaviour Evaluation by Modelling Steady-State Cornering
Nikola Avramov, Petar Simonovski, Tasko Rizov

This paper gives an overview of a vehicle cornering in a constant cor- nering radius, with constant speed. These constant values indicate steady state cornering or not changing its motion character over time. Even if the steering angle . starting from .0. (straight line driving) is reaching the constant value or the constant cornering radius, the vehi- cle is not following the desired path or evident is the under-steer or over-steer condition. As presented we can see the vehicle cornering, and it.s offset from the neutral driven vehicle. The vehicle is driving trough corner with greater radius. This means that the vehicle is under- steered. Neutral driven vehicle is the desired arc which can be followed by vehicle with neutral steer which means that when accelerating the driver doesn.t have to change the angle of the steering wheel.

Keywords: lateral forces, side slip angle, under-steer, over-steer, comering stiffness