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A Reconfigurable High-Q Antenna for Automotive Applications

Abstract

This paper is a review of the way in which the high-quality factor antennas can be used to integrate the VHF and HF car’s antennas in one device. The usage of the citizen band (CB) antennas in an HF band extends the environmental awareness of the driver and could increase the safety of the traffic. Usually, the citizen band transceiver with its antenna isn’t installed in a brand new car but the FM radio receiver it is. The main constraints that are related to the size difference between the two antennas (in FM and CB) make the main car manufacturers let the matter regarding the CB usage, open, at the choice of the buyer. The paper analyzes the technological advancements in the field and investigates some alternatives to the issue that will allow an opening through a single antenna usage for both radio bands.

Open access
Recycling of Foundry Sand Wastes in Self-Compacting Mortars: Use as Cementitious Materials and Fine Aggregates

Abstract

This work aims to study the possibility recycling of foundry sand wastes (FSW) as a cementations additive and fine aggregate in self-compacting mortars (SCM). For this, an experimental study was carried out to evaluate physical and mechanical properties of SCM. Firstly, sand is substituted by the foundry sand waste at dosages (0%, 10%, 30%, and 50%) by weight of the sand. Secondly cement is partially substituted by crushed foundry sand waste at different ratio (0%, 10%, 20%, 30%, and 50%) by weight of cement. The obtained results show that up to 50%, (FSW) can be used as fine aggregate for mortars without affecting the essential proprieties of mortar. However, beyond 50% of sand substitution, mortars lose their fluidity. The compressive strength of the mortars with 50% of cement substitution decreased compared to the control mortar. Value of the highest compressive strength recorded at 28 days, is of the order of 50 MPa for the mortar with 20% of cement substitution. Also, stress-strain curve show an acceptable mechanical behavior of FSW-based mortar at 50% of sand substitution.

Open access
Research of the Awareness and Preparedness for Floods of Foreigners Temporarily Residing in Bulgaria (Varna)

Abstract

A survey of 230 young people from 12 countries from Europe and Asia has been made. A high percentage of respondents (42 %) have experienced a flood. Most respondents (64.6 %) have not been informed whether they live in a flood-risk area. Self-assessment of respondents’ ability to provide first aid in flood situations is high (75 %), but the overall disaster preparedness is low because 78.9 % of respondents say they feel unprepared. The awareness and readiness of the studied group of 230 young foreigners temporarily residing the country are evaluated as follows: very good in providing CPR; with a good knowledge of flood epidemic consequences 80 % will take effective measures against the risk of intestinal contagious disease, and 81.5% will be saved from drowning because they can swim; lower, but still good preparedness for wound and arterial bleeding first aid (close to 40 %), mechanisms of contamination transmission by means of objects (33,3 %), use of disinfectants in the case of epidemics (45,4 %); very low readiness for rapid evacuation incases of floods and other disasters (only 5.3 % have a bug-out bag), etc.

Open access
Review of Normative Documents Applicable in Polish Navy in the Field of Measurement and Minimalization of Ships Physical Fields

Abstract

The article presents the general organization and operating principles of the national departmental standardization system. The characteristics of the tasks carried out in the area of defense and security, in the new formal, legal, and organizational conditions related to the passive defense of the Polish Navy ships are presented. In addition, the article contains a brief description of standardization documents in the area of national defense applied in the Armed Forces of Poland. One of the areas related to the passive defense and measurements of physical fields in the Polish Navy was also indicated.

Normalization is a way by which the Polish Navy can support the development of the military potential through the introduction of new equipment and weapons, which also contributes to the development of scientific research.

Open access
RFID Antenna for UHF Band

Abstract

This paper presents a method to increase the detection range for RFID readers in the UHF radio band. The design is following especially the ISO 18000-6C standardization demands for the UHF band, operating from 865 to 868 MHz in Europe and from 902 to 928 MHz in North America. These regulations are allowing the RFID tags to operate near the metallic surfaces and in a wider range than its counterparts at lower frequencies. The paper highlights the advantages offered by the array antenna, especially by the beamforming to increase the reader surveillance zone. The paper describes some additional techniques that are allowing the usage of the circular polarization to increase the reader sensing range and to improuve detection. The design starts with simulation and optimization using HFSS and ends with the measurements that validate the simulation results.

Open access
Some Aspects about Theoretical Static Rigidity and Experimental Static Rigidity of a New Elastic Coupling with Cylindical Bolts and Nonmetallic Elements

Abstract

The elastic couplings are frequently used in mechanical transmissions design, to take over the radial, axial and angular misalignments and also to take over the shocks and the overloads that could appear. In this paper is presenting some aspects about the construction of couplings with bolts using non-metallic elements, e.g. rubber, having different hardness, the elements involved in torque transmission, in this case elastic elements, having also different dimensions or forms, in the way to have a good elasticity and capacity of vibration absorbtion, determining theoretical static rigidity and experimental static rigidity of a new elastic coupling with cylindrical bolts and nonmetallic elements and compare of results for these values.

Open access
Spatial-Temporal Analysis of Land Cover and Use Changes Using Gis Tools. Case Study Băneasa Neighborhood, Bucharest

Abstract

The paper topic is related to the use of Geographic Information System and remote sensing in analysing the spatio-temporal dynamics of a post-socialist city. The purpose of this study is to highlight the changes in the land use of the Băneasa neighbourhood, located in the northern part of the capital city of Romania. The changes have been analysed from the nineteenth century to the present. The authors used historical mapping using old maps, as well as digitizing aerial photographs using the Geographic Information System. There has been an accelerated territorial evolution in the last 70 years, marked by the impact of the socialist policy of intensive urbanization, when the urban-type systematization was applied through the construction of collective dwellings, to which were added some important industrial units. After 1990, the dynamics of the tertiary sector generated significant changes in the physiognomy of the urban landscape, observing the increase of the built space (commercial spaces, new residential areas) at the expense of green spaces, tree nurseries, greenhouses and industrial sites. The most recent stage of evolution, however, has brought the most profound changes in the landscape of the Băneasa district, as a result of the new political and socio-economic context, marked by the collapse of communism. Thus, in the last 30 years, the capital city has registered an uncontrolled urban growth dynamic, this being characteristic of other large urban centres at the national level as well favoured by less strict, inconsistent and incomplete urban legislation.

Open access
The Structure of the Optimal Control in the Problems of Strength Optimization of Steel Girders

Abstract

The paper concerns a strength optimization of continuous beams with variable cross-section. The continuous beams are subjected to a dead weight and a useful load, the six (seven) combinations of loads were analyzed. Optimal design problems in structural mechanics can by mathematically formulated as optimal control tasks. To solve the above formulated optimization problems, the minimum principle was applied. The paper is an introductory and survey paper of the treatment of realistically modelled optimal control problems from application in the structural mechanics. Especially those problems are considered, which include different types of constraints. The optimization problem is reduced to the solution of multipoint boundary value problems (MPBVP) composed of differential equations. Dimension of MPBVP is usually a large number, what produces numerical difficulties. Optimal control theory does not give much information about the control structure. The correctness of the assumed control structure can be checked after obtaining the solution of the boundary problem.

Open access
Study of Phonic Pollution Produced by Car Traffic in Petrosani

Abstract

One of the most recent global environmental problems is noise pollution. Noise pollution is a component of environmental pollution. Like any other type of pollution, noise pollution has negative effects on environmental factors. The main sources of noise are: industry, urban areas and transport. To reduce the level of noise pollution is necessary to determine the pollution sources that cause. In this paper we will study the main areas affected by the noise pollution caused by the traffic in the city of Petrosani. We will also present solutions for reducing the pollution of the affected areas in Petrosani.

Open access
Study of Powder Particle Size Effect on Microstructural and Geometrical Features of Laser Claddings Using Response Surface Methodology RSM

Abstract

A continuous CO2 laser (10.6 µm wavelength) was adopted to investigate the influence of powder particle sizes on microstructural and morphological characteristics of laser claddings.

To study the potential of powder in controlling the incident laser energy, different average particle sizes of Ni-base powder were deposited on an austenitic stainless steel X3CrNi18-10 substrate. The energy value necessary to melt a mass m of powder was calculated. The results indicate that this energy decreases with particle sizes.

The claddings obtained with small particle sizes revealed a good morphological aspect and a low dilution of the cladding layer in the substrate, yet enough to create a very good metallurgical bond. The residual stress state was also influenced. Concerning modeling, we have elaborated residual stress model in the case of laser cladding by exploiting the response surface methodology (RSM), using a quadratic regression model. Combined effects of three laser cladding parameters on the residual stress is explored by a statistical analysis of variance (ANOVA). Results show that the residual stress is influenced principally by the power delivered by laser beam and by the scanning speed. It is also indicated that the size of powder particle is the dominant factor affecting the residual stress.

Open access