Application of liquified natural gas in road traffic : master’s thesis

Proteklih godina ukapljeni prirodni plin sve više ulazi kao gorivo u cestovni i pomorski promet, a polako se planira njegov ulazak i u željeznički promet. Ovaj trend potican je od strane državnih administracija nekih zemalja, međunarodnih organizacija koje u ukapljenom prirodnom plinu vide isplativiju i ekološki prihvatljivu alternativu dizelu. Diljem svijeta pokrenut je niz projekata izgradnje infrastrukture koja bi bila osnova za širu upotrebu ukapljenog prirodnog plina u različitim granama prometa. Ovaj rad ukratko opisuje tehnologiju ovakvih punionica, prednosti i mane vozila pokretanih ukapljenih plinom te se bavi mogućim utjecajima ovog projekta na razvoj transporta, energetike i očuvanja okoliša.During the last few years, liquefied natural gas has been established as an important fuel in road, marine and railroad traffic worldwide. This situation was supported by state administrations of some nations, multinational agencies and companies, which consider LNG to be more cost effective and environmentaly friendly alternative to the established diesel and other conventional fuels. Throughout the world, a series of projects has begun with a goal of building infrastructure for vehicles run by LNG. This thesis describes the technology used by fueling stations and vehicles of this type, pros and cons of LNG run vehicles, as well as possible implications of this project on the development of transport and the application of natural gas as an alternative fuel for sustainable development and environmental protection

Calculation of the frequency response and bandwidth in low numerical aperture step-index plastic optical fiber using time-dependent power flow equation

Time-dependent power flow equation is employed to calculate frequency response and bandwidth of low numerical aperture step-index optical fiber excited with Gaussian-like light source with large width. Both, frequency response and bandwidth, are specified as function of the fiber length measured from the input end of the fiber. Analytical and numerical solutions are compared and good agreement between results is obtained

The influence of nonlinear and linear defects on the light propagation through linear one-dimensional photonic lattice

In this paper, the light beam propagation through one-dimensional photonic lattice, possessing one nonlinear defect and one linear defect, has been investigated numerically. Different dynamical regimes have been identified in terms of the distance between the two defects, position of the incident light beam, the width of linear defect, the values of nonlinearity and presence of the transverse kick. Strong localized modes on the defects, breathing and zig-zag modes in the area between defects have been observed. It has been concluded that the width of the linear defect placed next to the nonlinear one influences localization of the beam at the nonlinear waveguide. On the other hand, the nonlinear defect, regardless of the values of nonlinearity, have a small influence on the beam propagation in photonic lattice. It has been observed that the transverse kick of the initial beam leads to the distortion of localized structures. By launching the light beam towards defects, the reflection of light has been noticed. Presented results can be useful for different applications, such as blocking, filtering and routing of light beam through optical media

E-Governance in Republic of Srpska - Challenges and Prospects

In order to ensure quality of life of its citizens, the European Union member states are in the process of modernisation of their public services through utilization of information and communication technologies (ICT). In this process, each state is selecting own way to meet citizens’ demands for provision of more quality, efficient and flexible public services. One of the main interests of actual Government in the Republic of Srpska (RS) is to protect economic interests of its citizens, as well as to transform its services and functions in order to improve overall quality of life in RS. The implementation of e-Government and e-Governance is one of the main strategic commitments. In order to meet these EU trends, the Government of the Republic of Srpska made first steps in introducing new public services to facilitate communication with its citizens. The Government of the Republic of Srpska recognized benefits of these trends and their impacts on the overall development of society and economy improvement of quality of life of its citizens. With the introduction of these modern services, the citizens in RS should skip lines and shorten the waiting time for response from Governmental bodies related to their requests that will give them more time for other activities.This paper gives brief analysis of challenges and prospects for implementation of e-Government and e-Governance initiatives, as one of the pillars for successful development of the Republic of Srpska as knowledge based economy and information society with benefits that improve citizens’ life. The paper also gives brief review of main strategic document, which gives governmental vision for implementation, as well as introduction of eSrpska- public administration portal

Modelling the Process of is Auditing in the Public Administration Using UML Diagrams

Although information system audit is a very important business process, at present this is not obligatory in the public administration institutions in Bosnia and Herzegovina and Republic of Srpska. Due to the importance of this process, this paper proposes a model for auditing of information systems in the public administration institutions. The model intends to explain the audit process using a visual representation of the process with UML diagrams. UML is an internationally recognised language for business process modelling and has a number of advantages over other similar languages and standards. Therefore, UML is selected in modelling for modelling of information system auditing process in the public administration institutions

Fuel Switch to LNG in Heavy Truck Traffic

Liquefied natural gas (LNG) use as a fuel in road and maritime traffic has increased rapidly, and it is slowly entering railroad traffic as well. The trend was pushed by the state administrations of mainly EU countries and international organizations seeing LNG as a cost-effective and environmentally friendly alternative to diesel. Different infrastructural projects for the widespread use of LNG in transport have been launched around the world. The main goal of this paper was to analyze use of LNG as a fuel for heavy trucks. Different aspects of LNG chain were analyzed along with economical and ecological benefits of LNG application. Filling stations network for LNG were described for the purpose of comparative analysis of diesel and LNG heavy trucks. Conclusion has shown that using LNG as propellant fuel has numerous advantages over the use of conventional fuels. The higher initial investment of the LNG road vehicles could be amortized in their lifetime use, and in the long-term they are more affordable than the classic diesel vehicles. In addition to cost-effectiveness, LNG road vehicles reduce CO2 emissions. Therefore, the environmental goals in transport, not only of the member states but worldwide, could not be met without LNG in heavy truck traffic

Theoretical Investigation of the Influence of Wavelength on the Bandwidth in Multimode W-Type Plastic Optical Fibers with Graded-Index Core Distribution

The bandwidth of multimode W-type plastic optical fibers (POFs) with graded-index (GI) core distribution is investigated by solving the time-dependent power flow equation. The multimode W-type GI POF is designed from a multimode single-clad (SC) GI POF fiber upon modification of the cladding layer of the latter. Results show how the bandwidth in W-type GI POFs can be enhanced by increasing the wavelength for different widths of the intermediate layer and refractive indices of the outer cladding. These fibers are characterized according to their apparent efficiency to reduce modal dispersion and increase bandwidth

The influence of nonlinear and linear defects on the light propagation through linear one-dimensional photonic lattice

In this paper, the light beam propagation through one-dimensional photonic lattice, possessing one nonlinear defect and one linear defect, has been investigated numerically. Different dynamical regimes have been identified in terms of the distance between the two defects, position of the incident light beam, the width of linear defect, the values of nonlinearity and presence of the transverse kick. Strong localized modes on the defects, breathing and zig-zag modes in the area between defects have been observed. It has been concluded that the width of the linear defect placed next to the nonlinear one influences localization of the beam at the nonlinear waveguide. On the other hand, the nonlinear defect, regardless of the values of nonlinearity, have a small influence on the beam propagation in photonic lattice. It has been observed that the transverse kick of the initial beam leads to the distortion of localized structures. By launching the light beam towards defects, the reflection of light has been noticed. Presented results can be useful for different applications, such as blocking, filtering and routing of light beam through optical media

Calculation of bandwidth of multimode step-index polymer photonic crystal fibers

By solving the time-dependent power flow equation, we present a novel approach for evaluating the bandwidth in a multimode step-index polymer photonic crystal fiber (SI PPCF) with a solid core. The bandwidth of such fiber is determined for various layouts of air holes and widths of Gaussian launch beam distribution. We found that the lower the NA of SI PPCF, the larger the bandwidth. The smaller launch beam leads to a higher bandwidth for short fibers. The influence of the width of the launch beam distribution on bandwidth lessens as the fiber length increases. The bandwidth tends to its launch independent value at a particular fiber length. This length denotes the onset of the steady state distribution (SSD). This information is useful for multimode SI PPCF applications in telecommunications and optical fiber sensing applications

Theoretical Investigation of Bandwidth in Multimode Step-Index Silica Photonic Crystal Fibers

Solving the time-dependent power flow equation (PFE) provides a useful method to study the transmission bandwidth of step-index silica photonic crystal fibers (SI SPCFs). The transmission bandwidth of these kinds of fibers is determined for different air-hole structures (different numerical apertures (NAs)) and different distribution widths of the Gaussian launch beam. The results indicate that the lower the NA of SI SPCFs, the higher the bandwidth (for example, for a lower NA of SI SPCFs, a bandwidth that is eight times larger is obtained at a fiber length of 3500 m). The narrower launch beam at short fiber lengths results in a wider bandwidth. The longer the fiber (>300 m), the much less the effect of the launch beam width on the bandwidth. The bandwidth becomes independent of the width of the launch beam distribution at the fiber length at which a steady-state distribution (SSD) is reached. These results are useful for some potential applications, such as high capacity transmission optical fiber systems