Bulletin of the Transilvania University of Brasov. Series I - Engineering Sciences

The Development of a Model for Energy Management in Small Buildings with Energy Cover from an Autonomous Hybrid Energy System (HES)

A. Vlissidis, I. Popescu, I. Kaliakatsos — Wed, 28 May 2008 00:00:00 +0000

This paper presents a model that has been developed to simulate the Energy Management for small isolated communities, such as islands, small buildings and rural villages, green houses, and in general for applications without access to an electric grid. This model is based on a hybrid stand-alone energy system (HES) and consists of five sub models, that are, a small Wind turbine generator (WG) model, a PV array model, the Battery back up storage model, the Diesel generator (DG) model and the Control model.

Optimal Design of the Mechanisms Using Multibody Systems Software

Catalin Alexandru — Wed, 28 May 2008 00:00:00 +0000

In this paper, we attempt to present a lot of aspects regarding the usage of multibody systems in the optimization process of the mechanical systems. The optimization of the virtual model is made in the following steps: parameterizing the virtual model, defining the design variables, defining the design objective for optimization, performing design studies in order to identify the main design variables, and optimizing the model on the basis of these variables. For applying the optimization algorithm, the hood mechanism for a storage compartment has been taken into account, using the multibody systems environment ADAMS of MSC Software.

Ecodesign - An Innovative Path towards Sustainable Development

L. Barsan, A. Barsan — Wed, 28 May 2008 00:00:00 +0000

One of the goals of this paper is to introduce the reader into Ecodesign. It represents the first from a series of papers on this subject based on the four teaching aids developed within the framework of an Erasmus curriculum development project. In this paper, the concept of Ecodesign is explained in the context of the design process and as part of a sustainable development. The paper represents a pleading not only for a good design, but also for an environmentally friendly one.

Determining the Water Loss Volume in an Experimental Installation

Mihaela Rodica Clinciu — Wed, 28 May 2008 00:00:00 +0000

The paper presents an experimental installation consisting of several water meters. The experimental installation is used for determining the water loss volume and the loss functions.

Calibration Life of the Measuring Devices - A Function of the Metrological Reliability

Ramona Clinciu — Wed, 28 May 2008 00:00:00 +0000

The paper presents an algorithm which can be used for the determination of the calibration life of the measuring devices as a function of the metrological reliability. The algorithm simulates the parameter deviation for the case of a normal distribution function. The case of the water meters is considered.

Elastic and Safety Clutches

Elena Eftimie — Wed, 28 May 2008 00:00:00 +0000

In machine-building practice, there are frequent situations when it is necessary to combine the functions of safety clutches with those of the elastic clutches. Because the combination of the two types of clutches leads to a system with a high level of complexity, it is essential, both from a technical and economic point of view, to conceive some clutches that may combine the two function groups, under the circumstances of a reduced complexity construction, similar to a simple clutch.

Computer Program for the Determination of the Measurement Bias Using the Control Chart Method

Nicolae Eftimie — Wed, 28 May 2008 00:00:00 +0000

The paper presents a computer program for the determination of the measurement bias, using the Control chart method. The program plots the xbar, the R chart and the hystogram of the measurements, and calculates: the bias, the repeatability standard deviation, the bias standard deviation and the limits of the confidence interval of the bias. Using these values, the program makes the decision about the acceptability of the measurement bias.

Global Supply Chain Management and Performance

Adriana Fota — Wed, 28 May 2008 00:00:00 +0000

A new approach on ‘supply’ emerged and developed against the background of an increasingly customer orientated market. Supply management must be regarded as a process which affects the whole cycle design-development-optimization-general management. In this context, we shall present and analyse in this paper, on the basis of some case studies, several performance models of the supply chain.

Project Selection and Criteria of Choice

Livia Huidan — Wed, 28 May 2008 00:00:00 +0000

The paper presents some aspects regarding project selection, as a process of evaluating projects, and the most important criteria in choosing a project selection model. It also presents some of the project evaluation factors, which should be considered in selection decisions.

The Influence of Geometric Parameters on the Tooth Addendum Thickness with Internal Gears

Gh. Moldovean, C.A. Bozan — Wed, 28 May 2008 00:00:00 +0000

This paper focuses on the way in which the pinion’s geometric parameters influence the tooth addendum thickness in the case of internal gears. The following parameters will be considered: the number of teeth in a pinion, the gear ratio and the helix angle.

On the Conceptual Synthesis of a New Cycloidal Planetary Reducer

L. Pascale, D. Diaconescu, M. Neagoe — Wed, 28 May 2008 00:00:00 +0000

Some new conceptual variants of cycloidal planetary reducer with bolts/rolls are proposed in this paper; these variants are generated by means of certain structural modifications of certain existing solutions in order to improve their performances. The conceptual solution of the reducer is then identified by ordering the conceptual variants with respect to certain technical and economic evaluation criteria.

Some Aspects about Improving the Accuracy Level of GPS Applications

A. Toma, I. Popescu — Wed, 28 May 2008 00:00:00 +0000

To obtain accuracy levels on the order of one to 10 meters, the differential correction is essential. The three main methods currently used for ensuring data accuracy are the real-time differential correction, the reprocessing real-time data, and the post-processing. Every method will achieve similar levels of accuracy, so the decision regarding which technique is appropriate will depend on factors such as project specifications, the end use of the data, and the sources available for differential correction.

On the Minimization of the Solar Tracker Incidence Angle

I. Visa, D. Diaconescu, V. Dinicu, B. Burduhos — Wed, 28 May 2008 00:00:00 +0000

This paper presents the modelling of the sun-ray unit vector and of a solar panel normal unit vector in the reference system of an observer from Earth. Using the resulted formulae set there is modelled and numerical simulated the sun ray-solar panel incidence angle variation. The comparative analysis of the results gives useful conclusions regarding the incidence angle minimization.

The Impact of Feature Weighting on the Fuzzy ARTMAP Neural Network

A. Cataron, L.M. Sasu, R. Andonie — Wed, 28 May 2008 00:00:00 +0000

The paper presents an extension of the Fuzzy ARTMAP model that employees the feature weights in the determination of the ART categories. The features weights measure the relative importance of each input in a data classification task.

Fiber Link Transmitter Communication Modem

Radu Gavrus — Wed, 28 May 2008 00:00:00 +0000

Fibre link communication modem is one of the multi-service networking solutions. The solution is suitable for data communications into adhoc computer networks or industrial networks. This paper presents ad-hoc solution design implementation of the fibre link radio based transmitter module, implemented into an FPGA, responsible for data framing packing. The system is corresponding with data link layer level from OSI reference model.

Total Respiratory Impedance Analysis Using Ladder Networks Analogy for Fractional-Order Models

C. Ionescu, A. Caicedo, R. de Keyser — Wed, 28 May 2008 00:00:00 +0000

Fractional-order parametric models are popular in applications in material sciences, but they are not applied to biological systems. Recent research showed that they seem a good choice to model the human respiratory impedance. The purpose of this contribution is to implement such a fractional-order model for the human impedance, with electrical ladder networks of integer-order. The conclusion is that the number of rungs is an important design parameter to obtain a good approximation.

Asynchronous Protocols for “Structured ASIC” Platforms

Razvan Jipa — Wed, 28 May 2008 00:00:00 +0000

Large and complex digital circuits require new modular architectures to integrate various building block modules with different requirements regarding the clock frequency. The paper presents the selection of the asynchronous communication protocol that allows to use GALS (Globally Asynchronous Locally Synchronous) architectures on “structured ASIC” (Application Specific Integrated Circuit) platforms to create a new class of digital circuits that can address the issues of large circuit design.

Embedded System with ATMEGA16 for Measuring Radon Concentration

Cs.Z. Kertesz, P. Ogrutan, I. Szekely — Wed, 28 May 2008 00:00:00 +0000

The paper presents a method for monitoring radon concentration in air using a detection chamber as transducer, an embedded system based on ATmega16 microcontroller for measuring the transducer output and a GPRS modem for sending measurement data to a remote center.

Reliability and Security Concerns in Low Rate Wireless Networks Inside Buildings and Outside

M. Machedon-Pisu, I. Szekely — Wed, 28 May 2008 00:00:00 +0000

The paper presents the strategies for establishing efficient and reliable data communication in wireless networks based on indoor and outdoor measurements with LQI and RSSI for network optimization, and the method for network nodes real-time localization which can be used in order to form a secure network.

Experimental Investigation on the Materials and Nanomaterials in Microwave Fields

G. Nicolae, P. Ogrutan, A. Mailat, L.E. Aciu — Wed, 28 May 2008 00:00:00 +0000

This paper present the measurement results obtained after testing the characteristics of new materials developed after studies and researches in the field of nanosciences. New materials are known as nanomaterials, with are important in a wide area of applications. The usefulness of nanomaterials becomes relevant as their behavior in various physical media in investigated. This paper presents the results of measurements on the attenuation of a microwave field in different types of nanomaterials. This paper was written in the framework of the 429/2006 CNCSIS project.

Zero-Voltage and Zero-Current Soft-Switched Full- Bridge PWM (ZVZCS-FB-PWM) DC/DC Converter

P. Scortaru, A. Tanase — Wed, 28 May 2008 00:00:00 +0000

new topology of an improved Zero-Voltage and Zero-Current Soft–Switched Full-Bridge Phase-Shifted PWM (ZVZCS-FB-PWM) DC/DC Converter for a battery charger application is analyzed and designed. To improve the conventional phase-shifted ZVS PWM converter, an auxiliary transformer and a small discrete inductor (commutation inductor) are added in the primary circuit of the power transformer. Experimental results from a 600 V/2.6 kW -70 kHz prototypes validate the design.

Model of Data Laboratory Integration for Excellence Research Sustaining

Delia Ungureanu — Wed, 28 May 2008 00:00:00 +0000

The paper presents a solution for the integration of information about different equipments used in research laboratories and of experimental data, in order to facilitate both the knowledge of logistic potential of research centres and the management of experimental data. The proposed solution allows integrated storage of different types of experimental data, their management and easy data access for other programs and users. It is software that manages research infrastructure.

Overview of Photovoltaics in the Distributed Power Generation Systems

D.M. Valcan, C. Marinescu — Wed, 28 May 2008 00:00:00 +0000

The photovoltaic (PV) energy sources have became a reliable alternative to the conventional energy sources due to their environment friendly and endless nature. The PV systems are often embedded in Distributed Power Generation Systems (DPGS). Due to the increasing number of DPGS connected to the public electricity grid, more standards have been developed. Thereby, the energy control methods must be improved in order to satisfy the rules. This paper presents an overview of the PV systems used in DPGS which are interconnected with the public grid.

Integrated Monitoring System Environment - Health Components and Their Role in the Communication System

C. Draghici, St. Ungurean, D. Perniu, M. Sica — Wed, 28 May 2008 00:00:00 +0000

When trying to define the components of the Integrated Monitoring System Environment - Health (IMS E-H) a great variety of institution and organization acting at different levels of the socio-economic system are identified. The paper schematically presents these types of institutions and organisation, that have been grouped in different categories and a specific syntagm has been attributed to each of these groups, the one defining its most relevant involvement in the communication process inside the IMS E-H: perturbing, affected, guarantying, evaluators, evaluators and controllers, controllers, communicators.

Wood Coating Nanostructurated Materials

L. Dumitrescu, D. Mihalevschi, I. Manciulea — Wed, 28 May 2008 00:00:00 +0000

The paper presents aspects regarding the synthesis of some new wood coating nanostructurated materials based combinations of alumina nanoparticles with functionalized acrylic and acrylic polyurethane copolymers, that leads to the enhancement of coating properties.

Photocatalytic Degradation of Dyes from Wastewaters of Textile Finishing Industry

A. Duta, R.A. Carcel — Wed, 28 May 2008 00:00:00 +0000

Textile finishing industry represents one of the biggest polluting industrial sectors. With an estimated water consumption of 160 m3/t and the presence of excess dye and heavy metals in the effluent, the textile finishing industry represents a great environmental concern. In order to remove the dyes from waste waters, photocatalytic methods can be applied. The principle is based on using low cost semiconductor material that absorbs solar energy to oxidize the dyes to non-polluting substances. The oxidation process is mainly due to the formation of HO• groups at the surface of the semiconductor that will react with the dye molecules.

Tailoring the Morphology of SnO2 Thin Layers

Al. Enesca, L. Andronic, A. Duta — Wed, 28 May 2008 00:00:00 +0000

The aim of the paper is to demonstrate the influence of different deposition techniques on the morphology of SnO2 thin films used as photocatalysts or sensors. An important aspect is represented by the precursor properties and deposition temperature. In most cases, the layers are involved in post-deposition treatment for improving the crystallinity and optoelectrical properties. Compared to the more widely used indium tin oxide (ITO), SnO2 films are inexpensive, chemically stable in acid and alkaline solutions, thermally stable in oxidizing environments at high temperatures, and also mechanically strong, which are important features for the fabrication as component in different devices.

Selective Coatings Used For Flate Plate Collectors

E. Ienei, M. Voinea, A. Duta — Wed, 28 May 2008 00:00:00 +0000

The efficiency of the photothermal solar energy conversion is strongly influenced by the absorber’s quality. The spectrally solar selective should absorb maximum solar radiation and the obtained thermal energy should be transferred with minimum heat re-radiation losses. These properties can be optimised by tailoring the surface properties. The paper presents the most important categories of the selective coatings used for solar thermal applications and their specific characterising methods.

Alumina Based Cermets Used As I.R. Absorber Coatings

L. Isac, L. Isac, E. Purghel, A. Duta — Wed, 28 May 2008 00:00:00 +0000

The paper presents the obtaining and preliminary characterization of Al2O3 films deposited by Spray Pyrolysis technique (SPD) from aqueous or water:ethanol solutions of AlCl3. The films, deposited onto microscopic glass substrates at temperatures varying from 150 ºC to 250 ºC were analyzed by using the UV-VIS spectrometry. The influence of the precursor solution composition and deposition parameters on the thickness and possible composition of the obtained films has been studied.

Sawdust Pre-Treatment for the Use as Heavy Metals Adsorbent in Wastewater Treatment

D. Lucaci, A Duta — Wed, 28 May 2008 00:00:00 +0000

Bibliographical Study Regarding the PVA-H Practicability in Bones Implanthology

G. Moise, S. Patachia — Wed, 28 May 2008 00:00:00 +0000

This is a study of the existent documentation regarding the application of the hydro-gels in the orthopedic surgery. The specialists in bone tissue engineering have developed until now several implant types made of resorbent polymeric skeletons that are supplementing or replacing with success tissues, articulations, tendons and ligaments that are broken or have different diseases.

An Innovative Method for the Separation of Organic Compounds

S. Patachia, C. Croitoru — Wed, 28 May 2008 00:00:00 +0000

Molecular imprinting has gained increasing research interest during the recent years. The paper would like to show how an apparently simple concept like molecular imprinting can lead to useful applications in different areas, such as environmental, medicine, food process industries and molecular biology.

Behaviour of Polyurethane-Barium Titanate Composite Material

M. Sica, M. Leca, C. Draghici — Wed, 28 May 2008 00:00:00 +0000

The paper presents a study on the behaviour of polyurethane - barium titanate composite material prepared using industrial polyurethane. The influence of the concentration of barium titanate filler on glass transition temperature and mechanical behaviour of the composite is studied. Some conclusions are pointed out.

Heavy Metals Removal from Multicomponents Cation Solution Using Alkaline Activated Fly Ash

M. Visa, A. Duta — Wed, 28 May 2008 00:00:00 +0000

The study aims to optimize the heavy metals immobilization on fly ash, as a low cost adsorbent. The fly ash is collected directly from the filter of CPHCET Brasov. Batch experiments were conducted at room temperature to evaluate the removal, by adsorption, of Cd2+, Cu2+ and Ni2+ from multi-cations solution. The surface of fly ash was modify by alkaline treatment with NaOH 2N solutions. The adsorption data were described using the Langmuir and Freundlich models. Key words: The study aims to optimize the heavy metals immobilization on fly ash, as a low cost adsorbent. The fly ash is collected directly from the filter of CPHCET Brasov. Batch experiments were conducted at room temperature to evaluate the removal, by adsorption, of Cd2+, Cu2+ and Ni2+ from multi-cations solution. The surface of fly ash was modify by alkaline treatment with NaOH 2N solutions. The adsorption data were described using the Langmuir and Freundlich models.

Environmental Impact of Copper Cermets Used As Selective Coatings for Flat Plate Collectors

M. Voinea, C. Bogatu, A. Duta — Wed, 28 May 2008 00:00:00 +0000

The utilisation of solar collectors is a pollution-free process based on renewable energy, helping to the CO2 reduction, the principal gas responsible for global heating. Flat plate collectors are the most common solar collectors due to their low cost. In order to improve their efficiency selective coatings are used. This paper presents an I.R. absorber coating, obtained via electrodeposition: Cu/CuOx cermet. The environmental impact of the substances used as precursors and deposition process is discussed.

Researches Regarding the Reliability and Degradation of the Automation Equipment of Tool-Machines

Gh. Bratucu, I. Capatana — Wed, 28 May 2008 00:00:00 +0000

The work presents the results of reliability studies achieved on two groups of 12 lathes with digital control SPT 32 type, where the advances train automation mechanism were with hydraulic, respectively electronic elements As compared to the predictable reliability value obtained with data from the specialist literature, the value of the operational reliability resulted by testing the lathes on a period of about 20000 working hours has emphasized important discrepancies.

Alternative Fuels for Vehicles Engines

A. Chiru, N. Ispas, C. Dumitrascu — Wed, 28 May 2008 00:00:00 +0000

The usage of alternative fuels in internal combustion engines can generally reduce harmful pollutants and exhaust emissions, improving the air quality. Alternative fuels in use today includes: ethanol, methanol, biodiesel, natural gas, propane, electricity and hydrogen. The alternative fuels represent a range of cleaner fuels on the market that can offer important environmental benefits and lower fuel costs comparative to fossil fuels.

Experimental Researches Regarding the Usage of Alternative Fuels for Vehicles Engines

D. Dumitrascu, A. Chiru — Wed, 28 May 2008 00:00:00 +0000

The main objective of the experimental research was the evaluation of the energetically and ecological performances in case of usage of some alternative fuels for internal combustion engines.

Application of Quality Function Deployment Method within a Technical Inspection Station for Automotive

Natalia Filip — Wed, 28 May 2008 00:00:00 +0000

In the new vision promoted by Quality Management, the quality is the main objective of the whole activity of an organization. Thus, it is not sufficient anymore only to verify the existence of quality - associated with the product (including here products and services, in accordance with the last edition of ISO 9000 standards) - but it is necessary to design, deploy and build step by step the quality. In order to improve the quality of the services done within technical inspection station, it was conceived a questionnaire that allow us to identify client’s demands and the importance level the client assign to each requirement. Considering the quality characteristics, besides a good professional of staff and a proper technical endowment of the station are also necessary good communication abilities.

An Experimental Approach Concerning the Discharge Profile for Geometric Variable Screw Feeders Used for Agro-Food Bulk Solids

D. Ola, S. Popescu, C. Furll — Wed, 28 May 2008 00:00:00 +0000

Screw feeders are devices suitable for handling a wide variety of bulk solid materials that have good flow ability characteristics and are often used as dosing feeders in food industry and agriculture. The manner in which material flows into the screw affects the flow characteristics of the feeding hopper, the residence periods of the material in various locations of the bunker and thus the properties of the dosed products. The present paper will present some experimental results regarding the discharging profile of the mass flow screw feeders with variable geometrical design.

Particularities of the Dynamic Stability of Fork Lift Trucks

Simion Popescu — Wed, 28 May 2008 00:00:00 +0000

The paper presents the equivalent dynamical model of the fork lift truck, specifying the exterior forces acting in the most difficult work situations: descending on a slope braking of the vehicle in translatory motion and acceleration of the fork while lifting the load. Based on the equivalent dynamical model, are elaborated the mathematical models describing the dynamical behaviour of the fork lift truck during moving or working. These models deliver the criteria for the overturning stability. By computer simulation of the mathematical models the longitudinal stability of the forklift truck is analysed with application for a constructive model of fork lift truck.

The Design of Finned Static Space Heaters

Daniela Sova — Wed, 28 May 2008 00:00:00 +0000

The radiators taken into consideration for further calculations and experiments are made of copper pipes with aluminum fins (quadratic fins). Starting from the expression of the overall heat transfer coefficient for a plane wall, there were calculated the heat fluxes transferred by conduction, convection and radiation from the working fluid to the environment, by mediation of the extended heat transfer surfaces. There were used the general equations of the fin adapted to the concrete case of the given dimensions.

The Study of the Heat Transfer Characteristics of the Static Finned Space Heaters

Virgil Ungureanu — Wed, 28 May 2008 00:00:00 +0000

The test of the radiators was made by use of experimental equipment with the capacity to achieve fluid parameters close to the nominal ones: the temperature of the hot water 90/70 °C and that of air 20 °C. It was applied to three radiators with the length of 1000 mm: with one, two and three heating modules all finned. The testing bench comprises an aggregate called constant temperature bath, thermometers, a hot water flow meter and a chronometer.

Theory of Digging up the Sugar Beet Root Crops

Volodymyr Bulgacov — Wed, 28 May 2008 00:00:00 +0000

New mathematical model which describes process of a beet root crop direct extraction from soil, realized under act of vertical disturbing force and tractive effort which are transmitted the root crop from a vibration digging out end-effector is developed. The sets of differential equations which solution has enabled to determine the law of the root crop movement during its direct vibration extraction are received.