1. Potential of using waste materials in flexible pavement structures identified by optimization design approachPrimož Jelušič, Süleyman Gücek, Bojan Žlender, Cahit Gürer, Rok Varga, Tamara Bračko, Murat V. Taciroğlu, Burak E. Korkmaz, Şule Yarcı, Borut Macuh, 2023, izvirni znanstveni članek Opis: This paper presents the design of geosynthetic reinforced flexible pavements and their modification by incorporating waste materials into bonded and unbonded layers of the pavement structure. The optimal design of flexible pavements was achieved by minimizing the construction cost of the pavement. The incorporation of waste materials into the pavement structure affects the material properties. Therefore, along with the traffic load, the effects of the material properties of the asphalt concrete, base layer, sub-base layer, and subgrade were analyzed in terms of pavement structure costs and CO2 emissions of materials used in pavement construction. In addition, a comparison was made between pavements with and without geosynthetic reinforcement in terms of design, optimum construction cost, and CO2 emissions. The use of geosynthetics is even more effective in pavement structures that contain waste materials in an unbound layer, both in terms of cost and CO2 emissions. The minimum value of the California Bearing Ratio of the subgrade was determined at which the use of geosynthetic reinforcement for pavement structure with and without the inclusion of waste materials is economically and sustainably justified. The use of geosynthetics could result in a 15% reduction in pavement structure cost and a 9% reduction in CO2 emissions due to the reduced thickness of unbound layers. In addition, reducing the CBR of the unbound layer from 100% to 30% due to the inclusion of waste materials implies a cost increase of up to 13%. While the present study is based on an empirical pavement design method in which pavement thickness is limited by the pavement thickness index, the same minimum thicknesses are obtained in the optimization process regardless of whether the objective function is the minimum construction cost or minimum CO2 emissions.
Ključne besede: pavement design, waste materials, optimization, minimum construction cost, CO2 emissions, geosynthetics, waste management
Objavljeno v DKUM: 18.09.2023; Ogledov: 107; Prenosov: 9
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2. Recent advances in the development of automotive catalytic converters: a systematic reviewLaura Robles-Lorite, Ruben Dorado Vicente, Eloisa Torres Jiménez, Gorazd Bombek, Luka Lešnik, 2023, pregledni znanstveni članek Opis: Despite the current boost in the use of electric vehicles to reduce the automotive sector’s footprint, combustion vehicles are and will be present in our cities in both the immediate and long term. In this sense, catalytic converters, which are exhaust gas post-treatment systems for vehicle emission control, are critical for complying with increasingly stringent environmental regulations. This work proposes a systematic review to identify the most relevant knowledge regarding the parameters (materials, geometries, and engine conditions), conditions (cold start, oxygen storage, and deactivation), and mathematical models to consider in the design of catalytic converters. The Scopus database contains 283 records related to this review’s objective. After applying the inclusion and exclusion criteria, 65 reports were retrieved for evaluation. A table was created to present the results and prepare this manuscript. The evaluation revealed that the following topics were active: the study of non-noble catalyst materials, as well as new substrate materials and geometries, for designing more compact and cost-effective catalytic converters; the development of strategies to improve conversion during cold starts; and the development of accurate and fast estimation models.
Ključne besede: automotive converters, catalytic converters, emissions reduction, exhaust gas post-treatment, catalyst deactivation, oxygen storage, numerical models
Objavljeno v DKUM: 06.09.2023; Ogledov: 70; Prenosov: 7
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5. Infrastructure planning and environmental protection : case study of SlovakiaMarián Gogola, Daniela Durcanska, Marta Hocova, 2016, samostojni znanstveni sestavek ali poglavje v monografski publikaciji Ključne besede: infrastructure planning, environmental protection, air pollution, transportation, traffic, emissions, Slovakia
Objavljeno v DKUM: 10.05.2018; Ogledov: 3896; Prenosov: 82
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8. Acoustic noise emissions caused by transformer in a DC/DC converter for welding appliactaions [!]Gorazd Štumberger, Klemen Deželak, Drago Dolinar, Beno Klopčič, 2012, objavljeni znanstveni prispevek na konferenci (vabljeno predavanje) Opis: This paper deals with the acoustic noise emissions caused by the transformer operating as a part of DC/DC converter in an industrial resistance spot welding system. The discussed DC/DC converter is schematically shown in Fig. 1. The three-phase alternating voltages (u1, u2 and u3) are rectified and smoothed in order to obtain almost constant DC-bus voltage UDC. The H-bridge inverter is used to supply the transformerćs primary winding with voltage pulses uH. The two transformerćs secondary windings are connected to the two output rectifier diodes (D1 and D2) which provide the direct welding current iL flowing through the load represented by LL and RL. A new control scheme forresistance spot welding systems was proposed in [1,2]. During the testing of the proposed control scheme it became evident that the proposed control scheme not only improves utilization of the iron core and prevent it from becoming saturated, but also substantially reduces the acoustic noise emissions caused by the transformer. The reasons for reduction of acoustic noise emission are discussed in this paper.
Ključne besede: DC/DC converter, acoustic noise emissions
Objavljeno v DKUM: 10.07.2015; Ogledov: 2440; Prenosov: 47
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10. Numerical and experimental study of water/oil emulsified fuel combustion in a diesel engineNiko Samec, Breda Kegl, Robert W. Dibble, 2002, izvirni znanstveni članek Opis: Numerical and experimental studies were made on some of the chemical and physical properties of wateržoil emulsified fuel (W/OEF) combustion characteristics. Numerical investigations of W/OEF combustion's chemical kinetic aspects have been performed by simulation of water/n-heptane mixture combustion, assuming a model of a homogenous reactor's concentric shells. The injection and fuel spray characteristics are analyzed numerically also in order to study indirectly the physical effects of water present in diesel fuel during the combustion process. The experimental results of W/OEF combustion in the DI diesel engine are also presented and discussed. The results of engine testing in a broad field of engine loads and speeds have shown a significant pollutant emission reduction with no worsening of specific fuel consumption.
Ključne besede: internal combustion engines, Diesel engines, combustion, emissions, numerical modelling
Objavljeno v DKUM: 01.06.2012; Ogledov: 2102; Prenosov: 108
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