A spatial decision support system for traffic accident prevention in different weather conditions

Natural conditions play an important role as determinants and cocreators of the spatiotemporal road traffic accident Hot Spot footprint; however, none of the modern commercial, or open-source, navigation systems currently provides it for the driver. Our findings, based on a spatiotemporal database recording 11 years of traffic accidents in Slovenia, proved that different weather conditions yield distinct spatial patterns of dangerous road segments. All potentially dangerous road segments were identified and incorporated into a mobile spatial decision support system (SLOCrashInfo), which raises awareness among drivers who are entering or leaving the predefined danger zones on the street network. It is expected that such systems could potentially increase road traffic safety in the future

Analysis of geometrical characteristics of pulsed nd:yag laser drilled holes in superalloy nimonic 263 sheets

Owing to their excellent mechanical and physical characteristics, superalloys are the most suitable material for use in hot sections of aircraft engines. Thousands of holes need to be drilled in constructive parts of machines, with laser technique emerging as the most effective. Laser drilling has been used to produce small diameter, accurately positioned holes, with little damage in regions around them, and in various materials. Effective laser employment of drilling of high quality holes for critical applications highly depends on correct selection and optimization of laser drilling parameters. In this work, the holes were drilled by a pulsed Nd(3+):YAG laser, with maximum average power of 160 W, in superalloy Nimonic 263 sheets, thickness 0,7 mm and 1,2 mm. The holes were observed by optical and scanning electron microscope. Geometrical characteristics of laser drilled holes that depend on laser parameters were investigated and analysed. The aim of this investigation was to find optimal laser parameters which would produce as much as possible regular holes

Analiza geometrijskih značajki rupa bušenih ND:YAG impulsnim laserom u limovima superlegure Nimonik 263

Owing to their excellent mechanical and physical characteristics, superalloys are the most suitable material for use in hot sections of aircraft engines. Thousands of holes need to be drilled in constructive parts of machines, with laser technique emerging as the most effective. Laser drilling has been used to produce small diameter, accurately positioned holes, with little damage in regions around them, and in various materials. Effective laser employment of drilling of high quality holes for critical applications highly depends on correct selection and optimization of laser drilling parameters. In this work, the holes were drilled by a pulsed Nd3+:YAG laser, with maximum average power of 160 W, in superalloy Nimonic 263 sheets, thickness 0,7 mm and 1,2 mm. The holes were observed by optical and scanning electron microscope. Geometrical characteristics of laser drilled holes that depend on laser parameters were investigated and analysed. The aim of this investigation was to find optimal laser parameters which would produce as much as possible regular holes.Zbog svojih odličnih mehaničkih i fizikalnih značajki, superlegure su najpogodniji materijal za uporabu u toplim sekcijama zrakoplovnih motora. U konstrukcijskim dijelovima strojeva treba izbušiti tisuće rupa, za što se kao najučinkovitija pokazala laserska tehnika. Bušenje laserom koristi se za proizvodnju malih promjera, točno pozicioniranih rupa, s malim oštećenjima u području oko njih i u različitim materijalima. Učinkovita uporaba lasera za bušenje rupa visoke kvalitete za kritične primjene uvelike ovisi o ispravnom izboru i optimiranju parametara bušenja laserom. U ovom radu, rupe su izbušene Nd3+:YAG impulsnim laserom, uz maksimalnu prosječnu snagu od 160 W, u limovima superlegure nikla Nimonic 263, debljine 0,7 mm i 1,2 mm. Rupe su promatrane optičkim i skenirajućim elektronskim mikroskopom. Istražene su i analizirane geometrijske značajke laserski bušenih rupa, koje ovise o parametrima lasera. Cilj ovog istraživanja bio je pronaći optimalne parametre lasera koji bi omogućili što pravilnije rupe.[http://www.tehnicki-vjesnik.com

Suitability of natural rock materials in Bosnia and Herzegovina for pavement construction

Today, following the maximum evolution of road transport, there is a great need for using only the highest quality materials for the construction of modern roads. All these materials lay around us, but they need to be properly utilized, which assumes the knowledge of their properties and predicting behavior in completed structures. There is enough capacity to obtain stone aggregates for the production of all pavement layers in Bosnia and Herzegovina. This paper outlines procedure and defines the basic tests of rock materials in order to demonstrate their usefulness for the construction of pavements in Bosnia and Herzegovina. It gives a brief overview of the main geological features of the area, and state and describe the quarries with the biggest capacity. The main objective of this paper is to determine whether the materials, owned by Bosnia and Herzegovina, have sufficient quality to be used for the construction of pavements, as well as where and how they can be used

Numerical modelling of the reinforced concrete influence on a combined system of tunnel support

The paper presents the experimental, laboratory determined rheological-dynamic analysis of the properties of fiber reinforced concrete, which was then utilized to show nonlinear analysis of combined system of tunnel support structure. According to the performed experiments and calculations, different processes of destructive behavior of tunnel lining were simulated in combination with elastic and elastic-plastic behavior of materials taking into account the tunnel loading, the interaction between the fiber reinforced concrete and soil, as well as the interaction between the fiber reinforced concrete and the inner lining of the tunnel

Physical Activities of Adolescents and the Level of Knowledge on the Impact of Their Diet on Their Overall Health

The period of adolescence is a period of rapid biological, physical and social changes. Diet of adolescents is based on eating large amounts of fast food. The aim of this research was to determine the relationship between high school students in several cities of the Republic of Srpska (Banja Luka, Gradiška, Srbac, Teslić and Čelinac) and their attitude towards food and the consumption of fast food, as well as food products that are commonly found in their menu. In this paper, a survey among high school students of both sexes, aged between 15 and 19 was conducted. The survey included 12 questions that can be classified into three groups: general information about the students, the data on physical activities of adolescents who consume “fast food” in their diet and information about their knowledge about the impact of the diet on their overall health. A great number of students (89.90%) do not think that fast food belongs to the group of “healthy” food, and they think (82.70%) that it has impact on their overall health. More than half of the students (52.90%) are satisfied with their body weight. There is about the same number of students who think that they are overweight (23.90%) or underweight (23.20%). The vast majority of students (92.80%) have not still had acute health problems due to the consumption of fast food. 58.60% of the students are partially satisfied with their diet, 31.10% are satisfied with their diet, and 61.3% of them would like change their diet

Costs of performance based maintenance for local roads: Case study Albania

The provision and maintenance of road infrastructure is a major global business, consequently it is essential that road maintenance services are provided in the most cost effective manner. Without regular maintenance, roads can rapidly fall into disrepair, preventing realization of the longer term impacts of road improvements on development, such as increased agricultural production and growth in school enrollment, which is of particular importance for a network of local (access) roads. Inadequate local roads maintenance in Albania is proposed to be solved by implementing performance based maintenance approach for which the costing exercise is presented within the paper

Proposal for reconstruction of an access street in Subotica

Residential and commercial construction zones, particularly if they are located in already constructed, practically inherited, parts of urban areas, have a large number of constraints into which traffic communication need to be fit. The primary importance in such circumstances is related to provision of approach to facilities and parking spaces, as well as to the interaction of motor vehicles, pedestrians and cyclists. Program indicators, such as the mean vehicle speed, flow, level of service, etc., lose their meaning, and even become undesirable phenomena that should be reduced to an acceptable level through the planning and design procedures. The work presents proposal for reconstruction of Petra Drapšina Street in the central city zone of Subotica which is based on an analysis of program requirements and available space

ACTIVE POWER LOSS MINIMISATION BY NEWTON METHOD ON THE CROATIAN ELECTRIC ENERGY SYSTEM (EES)

U radu je opisan problem optimalnih tokova snaga s naglaskom na minimiziranje gubitaka djelatne snage. Predloženo je rješavanje problema Newtonovom metodom, tehnikom nelinearnog optimiranja s ograničenjima. Opisana metoda ispitana je na modelu prijenosne mreže Hrvatske. Za ulazne podatke proračuna korišteni su stvarni podaci. Rezultati su pokazali opravdanost optimiranja tokova snaga radi ekonomičnog upravljanja prijenosnom mrežom te održavanja sigurne razine napona u sustavu.The paper gives an overview of optimal load flows where the minimization of active power losses is stressed. The solution to the problem is proposed by the Newton method using a non-linear optimization technique with boundaries. The method described is tested on the model of the Croatian transmission network. For input data, real data are used. The results showed proof of load flow optimization in order to realize economic transmission network control and keep the voltage level secure in the system

Modeling a Reaction Section of a Commercial Continuous Catalytic Reformer

Continuous catalytic reforming (CCR) is known to convert refinery naphtha to a high-octane liquid product, also known as the reformate. In this paper, a First Principle Reaction Section Model for a CCR process is presented. Even though CCR is a well-established technology, the application of advanced, real-time optimization techniques that are able to quickly respond to any imposed changes onto the process, are necessary in the refinery business. This becomes particularly important as a result of changes in profit margin, changes in operating cost, and the introduction of new environmental legislations. Hence, we present a kinetic model for the CCR process using the so-called "lumped" concept. The reactors have been modeled using a quasi-steady-state approach. The unknown model parameters have been estimated by bench marking the First Principle Reaction Section results with a commercial CCR process owned by the Hungarian Oil and Gas Public Limited Company (INA-MOL). The proposed model has been tested and compared to data obtained from an existing CCR plant. The predictions of the model were found to be in good agreement with the experimental data. The relative absolute errors between the measured and model estimated variables have been found to be lower than 2%. The relative absolute error associated with the required fired heater duties were less than 1.0%. Simulating the reaction section of the CCR process requires less than 0.1 s of CPU time, which clearly indicates that this model can be very suitable for performing optimization studies. Moreover, this study shows that, although there is fluctuation in the composition of feedstock, the lumped kinetic approach was capable to predict the behavior of the CCR process well