Strojniški vestnik 

About: Strojniški vestnik is an academic journal published by University of Ljubljana. The journal publishes majorly in the area(s): Engineering & Computer science. It has an ISSN identifier of 0039-2480. It is also open access. Over the lifetime, 373 publications have been published receiving 1895 citations. The journal is also known as: Journal of mechanical engineering.

A performance comparison between an air-source and a ground-source reversible heat pump

Abstract: In this study the performance of a reversible ground-source heat pump, coupled to a municipality water reticulation system, is compared experimentally and with simulations to a conventional air-source heat pump for spacecooling and heating. A typical municipality water reticulation system comprises hundreds of kilometres of pipes designed in loops that will ensure adequate circulation of the water. This result's in a substantial heat exchanger with great potential. Indirect heat transfer occurs between the refrigerant and ground via the municipality water reticulation system that acts as the water-to-ground heat exchanger. The experimental and simulated comparisons of the ground-source system to the air-source system are conducted in both the cooling and heating cycles. Climatalogical statistics are used to calculate the capacities and coefficients of performance of the ground-source and air-source heat pumps. Results obtained from measurements and simulations indicate that the utilisation of municipality water reticulation systems as a heat source/sink is a viable method of optimising energy usage in the air-conditioning industry, especially when used in the heating mode.

Practical Applications of Set-Based Concurrent Engineering in Industry

Abstract: Set-Based Concurrent Engineering is sometimes seen as a means to dramatic improvements in product design processes. In spite of its popularity in literature, the number of reported applications has so far been limited. This paper adds new information by describing implementations of Set-Based Concurrent Engineering in four product developing companies. The research took a case study approach, with the objective to investigate if the principles of Set-Based Concurrent Engineering can improve the efficiency and the effectiveness of the development process. The study shows that set-based projects can be driven within an existing organization, if given proper support. The participants claim that a set-based approach has a positive effects on development performance, especially on the level of innovation, product cost and performance. The improvements were achieved at the expense of slightly higher development costs and longer lead time. However, the positive effects are dominating and the companies involved intend to use Set-Based Concurrent Engineering in future projects when appropriate.

Basic Quality Tools in Continuous Improvement Process

Abstract: If organizations wish to achieve continuous quality improvement they need to use appropriate selection of quality tools and techniques. In this paper a review of possibilities of the systematic use of seven basic quality tools (7QC tools) is presented. It is shown that 7QC tools can be used in all process phases, from the beginning of a product development up to management of a production process and delivery. It is further shown how to involve 7QC tools in some phases of continuous improvement process (PDCA-cycle), Six Sigma (DMAIC) and Design for Six Sigma (DAMDV) methodologies, and Lean Six Sigma.

Elastocaloric cooling : state-of-the-art and future challenges in designing regenerative elastocaloric devices

Abstract: The elastocaloric cooling, utilizing latent heat associated with martensitic transformation in shape-memory alloys, is being considered in the recent years as one of the most promising alternatives to vapour compression cooling technology. It can be more efficient and completely harmless to the environment and people. In the first part of this work, the basics of the elastocaloric effect (eCE) and the state-of-the-art in the field of elastocaloric materials and devices are presented. In the second part, we are addressing crucial challenges in designing active elastocaloric regenerators, which are currently showing the largest potential for utilization of eCE in practical devices. Another key component of elastocaloric technology is a driver mechanism that needs to provide loading for active elastocaloric regenerators in an efficient way and recover the released energy during their unloading. Different driver mechanisms are reviewed and the work recovery potential is discussed in the third part of this work.

A Model of Surface Roughness Constitution in the Metal Cutting Process Applying Tools with Defined Stereometry

Abstract: The process of surface roughness formation is complex and dependent on numerous factors. The analysis of the latest reports on the subject shows that mathematical relationships used for determining surface irregularities after turning and milling are not complete or accurate enough and, therefore, need to be corrected. A new generalized mathematical model of roughness formation was developed for surfaces shaped with round-nose tools. The model provides us with a quantitative analysis of the effects of the tool representation, undeformed chip thickness, tool vibrations in relation to the workpiece, tool runout (for multicutter tools) and, indirectly, also tool wear. This model can be used to prepare separate models for most of the typical machining operations. Surface roughness is represented here by two parameters Ra and Rt. Simulations carried out for this model helped to develop nomograms which can be used for predicting and controlling the roughness Ra of surfaces sculptured by face milling.