Construction of Road Safety Composite Indicator Using Grey Relational Analysis

Aggregation of different variables into one road safety performance index is a popular concept in evaluating road safety and comparing the performance of territories/entities. This paper presents the development of a novel and innovative weighting methodology using grey relational analysis. Based on the proposed model, ten hierarchical road safety indicators were selected in terms of a two-layered model with three categories related to behaviour, safety and system. Grey weights are assigned to the categorized indicators in each layer, and the grey road safety composite indicator for each entity (21 selected territories) is calculated by the weighted sum approach. With relatively high weights, this systematic methodology can serve the policy makers in targeting the risk domains where improvements are needed. The results clearly illustrate effectiveness in addressing a large number of indicators with hierarchical structures

DYNAMIC BEHAVIOR OF TWO ELASTICALLY CONNECTED NANOBEAMS UNDER A WHITE NOISE PROCESS

This paper investigates the almost-sure and moment stability of a double nanobeam system under stochastic compressive axial loading. By means of the Lyapunov exponent and the moment Lyapunov exponent method the stochastic stability of the nano system is analyzed for different system parameters under an axial load modeled as a wideband white noise process. The method of regular perturbation is used to determine the explicit asymptotic expressions for these exponents in the presence of small intensity noises

Combustion characteristics of several types of biofuel in a diesel engine

Interesovanje za alternativna goriva koja bi se koristila za pogon motora sus je veoma veliko u čitavom svetu. Zato se istraživanja vezana za ovu problematiku vrše u mnogim vodećim svetskim laboratorijama za motore. Razlog ovog interesovanja su dostupnost ovakvih goriva, povoljne ekološke karakteristike i pozitivan uticaj na ekonomije zemalja koje ovakva goriva mogu da proizvode. U predmetnom radu se daje deo rezulta veoma kompleksnih i dugotrajnih istraživanja dinamike procesa sagorevanja kod dizel motora pogonjenog metilestrima biljnih ulja i to otpadnog palminog jestivog ulja, sojinog ulja i ulja uljane repice. Poređenje promena u radnom procesu motora, pre svega procesu sagorevanja, je vršeno pri sinhronizovanom radu motora na uobičajenim standardnim dizel gorivom mineralnog porekla. Analizom zakona (toka) sagorevanja svakog pojedinačnog goriva, utvrđeno je da postoje razlike koje nisu velikog karaktera, iz čega se može zaključiti da su goriva proizvedena iz biljnih ulja, a po važećem standardu, veoma kvalitetna goriva za pogon dizel motora. Ovo daje mogućnost naročito poljoprivrednim gazdinstvima da samostalno proizvode deo potrebnog goriva sa sopstvenih zemljišnih parcela uz uslov da poseduju odgovarajuću opremu za proizvodnju biodizela.Alternative propulsion fuels for diesel engines were highlights for a variety of research activities within a large number of R&D labs in the world. Curiosity, as well as basic interest in alternative fuel has been immense because of its reproducibility, renewability, as well as good ecological characteristics. Another reason for this interest is a favorable impact on the economies of the countries engaged in their production, by processing that kind of bio fuel. This paper presents the results of testing and research of the three types of alternative fuel gained from bio oil. Analyses and comparison of the dynamics of combustion process of these alternative fuels were done in relation to the reference diesel fuel. Burning process of methyl esters rapeseed (RME100), soya oil (SME100), waste cooking palm oil (PME100), as well as of regular Euro diesel fuel were investigated. It was found that these fuels were highly usable in diesel engines if they had been produced according to a proper standard procedure under standard EN 14214. The application of bio fuel is also very interesting for the propulsion of agricultural engines and machinery, because it enables the individual farming of bio fuel products necessary for the appropriate own machinery

Combustion characteristics of several types of biofuel in a diesel engine

Alternative propulsion fuels for diesel engines were highlights for a variety of research activities within a large number of R&D labs in the world. Curiosity, as well as basic interest in alternative fuel has been immense because of its reproducibility, renewability, as well as good ecological characteristics. Another reason for this interest is a favorable impact on the economies of the countries engaged in their production, by processing that kind of bio fuel. This paper presents the results of testing and research of the three types of alternative fuel gained from bio oil. Analyses and comparison of the dynamics of combustion process of these alternative fuels were done in relation to the reference diesel fuel. Burning process of methyl esters rapeseed (RME100), soya oil (SME100), waste cooking palm oil (PME100), as well as of regular euro diesel fuel were investigated. It was found that these fuels were highly usable in diesel engines if they had been produced according to a proper standard procedure under standard EN 14214. The application of bio fuel is also very interesting for the propulsion of agricultural engines and machinery, because it enables the individual farming of bio fuel products necessary for the appropriate own machinery

Evaluation of Road Safety Performance Based on Self-Reported Behaviour Data Set

Self-reported behavioural data, being often linguistic variables that represent a qualitative measure of respondents’ opinions/attitudes, are vague, uncertain, and fuzzy in nature. A road safety performance index, based on these fuzzy data, should consider this uncertainty. In this study, fuzzy numbers were used to describe self-reported behaviour on Montenegrin roads, which was further integrated into the data envelopment analysis (DEA), a technique for measuring the relative performance of decision-making units (DMUs). The vagueness of the performance scores obtained in this way was treated with grey relational analysis (GRA). GRA was applied to the cross-efficiency (CE) matrix constructed by the DEA to distinguish Montenegrin municipalities’ performance, with the main goal of describing road safety in the observed territories in the environment of uncertain/grey data. It is concluded that the proposed DEA–GRA model, based on fuzzy data, provides a more reasonable and encompassing measure of performance, and with which the overall ranking position of municipalities can be obtained

Evaluation of Road Safety Performance Based on Self-Reported Behaviour Data Set

Self-reported behavioural data, being often linguistic variables that represent a qualitative measure of respondents’ opinions/attitudes, are vague, uncertain, and fuzzy in nature. A road safety performance index, based on these fuzzy data, should consider this uncertainty. In this study, fuzzy numbers were used to describe self-reported behaviour on Montenegrin roads, which was further integrated into the data envelopment analysis (DEA), a technique for measuring the relative performance of decision-making units (DMUs). The vagueness of the performance scores obtained in this way was treated with grey relational analysis (GRA). GRA was applied to the cross-efficiency (CE) matrix constructed by the DEA to distinguish Montenegrin municipalities’ performance, with the main goal of describing road safety in the observed territories in the environment of uncertain/grey data. It is concluded that the proposed DEA–GRA model, based on fuzzy data, provides a more reasonable and encompassing measure of performance, and with which the overall ranking position of municipalities can be obtained

Spatial flow velocity distribution around an inlet port/valve annulus

An experimental investigation of the airflow through inlet port of a standard production direct injection diesel engine is presented. The investigation comprises mass flow rate and pressure drop measurements at fixed valve lifts, and spatial distributions of mean and r.m.s. velocity components around the port/valve annulus measured under steady flow conditions by special designed miniature hot-wire anemometer X probe. The results show that the velocity field is distributed non-uniformly across the valve gap and around valve periphery. Nonuniformity is more expressed at higher valve lifts. Flow instability in a jet leaving the port (jet flapping) is also evident since the skewness and kurtosis of the velocity probability distribution function depart from the Gaussian form. The presented experimental method, based on the application of miniature multiple hot-wire probes, makes possible investigation of flow performances of an inlet port and poppet valve assembly of a production engine head without any modification for ensuring an optical access within the port/cylinder

Experimental and Numerical Testing of Ambient Temperature Impact on Lifespans of Cuffs of Vehicles’ Steering Systems

The steering system represents one of the most important systems of active safety in vehicles. The process of a steering system failure usually starts with the failure of its protective element (cuff). Numerous factors influence a cuff’s lifespan, but the research subject of this paper is the impact of ambient temperature. The goal of this research is the experimental verification of the finding that vehicles used in northern areas require more frequent interventions in their steering systems than vehicles used in the south. A simulator performing a motion similar to the work of a cuff during a vehicle’s motion was made for the purpose of the research. A refrigerating chamber where cuffs were tested at temperatures from −4 °C to −20 °C was also made. A numerical analysis, with the ANSYS software environment, was also carried out. The numerical analysis shows that the failure of a cuff could be expected at almost the same point at which it was experimentally proven. Therefore, the failure, namely the breaking of a cuff, is not only a consequence of the material’s fatigue due to a big number of oscillations, but it also depends upon the impact of ambient temperature where the vehicle is used