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Influence analysis of the main types of defects and damages on bearing capacity in reinforced concrete elements and their research methods

Abstract

In current economic trends, changes in construction using are required. It usually leads to changes in value and type of the working load on building structures, with the requirement to rate the technical state and replace or strengthen the elements. An important aspect of determining the residual bearing capacity of damaged bending reinforced concrete elements is the research concerning the influence of difference defects and damages on the change of strength and deformability. In the article main types of damages and defects, methods of studies of damaged reinforced concrete elements and the expediency of usage of this elements are described. However, most methods are suitable only for certain defects and damages due to the large complexity of calculations and the consideration of multifactoriality. Significant complexity of a single method for calculating damaged elements depends on the possible changing stress strain state of an element in combination with certain defects and damages, the presence of a non-complete separation where during loading or alteration of the damaged element the fractions become included in the work, reinforced concrete is the composite material which carrying complexity in calculating the joint work of its components.

Open access
LEAN Production issues in the organization of the company - results

Abstract

The key to the functioning of enterprises in today's market is the concept of flexibility, which is mainly associated with adapting to very dynamically changing customer requirements. The basis for this approach is, among others, the realisation of serial production, products created for the customer's order in the quantity and time defined in orders. The LEAN Managemnt and LEAN production approach is a solution dedicated to meeting market assumptions. The LEAN concept, which both in the organization of production and management is focused on dynamic response to changes in the environment. The term LEAN represents numerous improvements to the organization, tools and techniques used to reduce and eliminate individual processes (or parts thereof) that are unnecessary activities. The key to analysing entire processes and defining unnecessary activities is thorough observation and selection of dedicated solutions. In the set of LEAN tools, you can find a lot of possibilities, from organization of a workstation itself, to a thorough quantitative analysis of times and process sequences, from simple facilities to complex technological solutions. The article presents the results of the assembly process analysis, indicates the point of product differentiation (marking for the client) and presents the map of organizational and preparatory activities for this process. The presented results are part of the activities within organization of the LEAN approach, currently having priority for the Research entity organisation improvement team.

Open access
Reversible Supply Chain in function of competitiveness

Abstract

Supply Chain makes the flow of goods, services and information from suppliers, through transport, producers, distributors, retailers to end customers. Big producers opt for a strategy of outsourcing logistic services, especially storage, delivery, and distribution services to end-customers. Commitment to the strategy of outsourcing, at the same time, is the strategy of focus on the core business. Small producers, especially manufacturers of agricultural food products, have recently opted to avoid intermediaries in the transport and distribution of the product to the end customer. All in order to increase the quality of their own products and increase the competitiveness by eliminating the costs of intermediaries in transport and distribution. This is achieved by merging and shortening the supply chain. The EU has established an institutional framework regulating the operations of producers through a short supply chain. The market situation requires further optimization by producers due to lack of labour and the need to increase competitiveness and leads to the emergence of a reversible supply chain phenomenon. In the paper, the author, by applying general and special scientific methods of cognition, explores the advantages and shortcomings of the short and reversible supply chain, derived from the traditional and modern supply chain model.

Open access
Waste Management Integration with Green Quality Function Deployment (G-QFD) for Healthcare Centre

Abstract

High doses of medical waste evidence that health waste management is problematic. A case study was conducted at various health institutions. This research analyzes various issues in the area of medical waste management. The research examines the perception of staff regarding medical waste management. The purpose of the study is to investigate the level of knowledge, attitudes and role of health practitioners in the management of medical waste.

Here the quality index and the environmental index of two health centers are studied; one is a private hospital and the other one a state hospital and compares these two indices with a questionnaire.

To provide environmentally friendly services, customers and environmental criteria have to be taken into account in the decision-making process and distributing the Green Quality Function provides a very useful way to achieve this goal.

Open access
Bending fatigue strength coefficient the low carbon steel with impurities

Abstract

The article discusses the results of a study investigating the effect of the number of fine non-metallic inclusions (up to 2 μm in size) on the fatigue strength of structural steel during rotary bending. The study was performed on 7 heats produced in an industrial plant. Fourteen heats were produced in a 100 ton oxygen converter. All heats were subjected to vacuum circulation degassing.

Steel sections with a diameter of 18 mm were hardened and tempered at a temperature of 200, 300, 400, 500 and 600°C. The experimental variants were compared in view of the applied melting technology and heat treatment options. The heat treatments were selected to produce heats with different microstructure of steel, from hard microstructure of tempered martensite, through sorbitol to the ductile microstructure of spheroidite. The results were presented graphically, and the fatigue strength of steel with a varied share of non-metallic inclusions was determined during rotary bending. The results revealed that fatigue strength is determined by the relative volume of fine non-metallic inclusions and tempering temperature.

Open access
Context of production engineering in management model of Value Stream Flow according to manufacturing industry

Abstract

The popularity of visual management in the lean concept is caused by the possibility to apply it in solving different kind of issues related to reduce waste or process planning. The adaptations of VSM is focused on stream flow, identifying waiting and productive times in accordance to material and information flow. In this paper five basic areas of value stream flow management have been presented and characterized. Discussion under the 5 areas on the VSM process included identifying the dominant stream in the area and the range of factors affecting the flow of the stream. Based on an observation of processes in the manufacturing industry and a literature review, the graphic model of mutual cooperation between value stream areas (1-5) has been presented.

Open access
Experimental Verification of Method to Synthesize the Track Vertical Irregularities

Abstract

The paper focuses on the experimental verification of the results derived from numerical simulations, based on a model of the bogie-track system, where the vertical track irregularities are introduced in the form of a pseudorandom function. This function comes from an original method of synthesizing the vertical track irregularities, depending on the geometric quality of the track and on the velocity. To verify the method, the root mean square (RMS) of the simulated accelerations in the axles and the bogie frame against each axle is compared to the experimental accelerations within the frequency range of wavelengths of the track vertical irregularities from 3 to 120 m. The results have shown a good correlation between the simulated RMS accelerations for a low quality track and the measured RMS accelerations.

Open access
How can people be convinced to buy electric cars? – case of Slovenia

Abstract

Electric cars represent a promising energy-and carbon-efficient alternative to internal combustion engine cars. However, as mobility behaviour is highly habitual, convincing people to switch from conventional cars to electric is challenging. In the following research, which was carried out in the past years in Slovenia, an attempt was made to determine what influences people’s buying habits and what would motivate them to buy an electric car. It appeared that the most relevant factor for not purchasing electric cars is, firstly, its overall too high price, and, secondly, short driving ranges. Different studies, as well as the results of the following research have revealed that there is no single measure which would dramatically increase the demand for electric cars. The solution is to combine different measures or strategies like Top – Down and Bottom – Up, where both the government and car industry should come across.

Open access
Innovative Calculation Method of the Productivity of Vibrating Screens Used in Mineral Aggregates Sorting

Abstract

In the process of preparing cement or asphalt concrete – frequently used in ways, roads and access road construction, it is necessary to sort out poly-dispersed granular mixtures from bilge deposits or quarries. The mechanical sieving performs the separation of the granules on dimensional sorts (the size of graded grains can be 1... 70 mm) by means of machines called screeners. In the case of vibrating screeners, the working body (the sieve) presents a vibratory movement that ensures a high productivity of the screening machine and a very good quality of the final products obtained. The article studies the productivity of the vibrating screen used in mineral aggregates sorting process obtained by different methods. In this regard, a pragmatic simplified formula called Pragma is proposed, a formula which was tested with good results in situ experiments done on a bi-mass vibrating screen in a pilot station.

Open access
Keeping Higher Education Aligned with the Requirements and Expectations of the Knowledge-Based Economy

Abstract

Paper describes the procedure for developing academic programs which are properly aligned to the requirements of the knowledge-based economy. The paper also addresses the continuous quality improvement (CQI) process with the CQI loop closing on the program level and the course level. This process is needed to make continuous adjustments to an academic program, so that the program is always aligned to the constantly-changing needs of the economy. Paper also discusses the system of mutual dependency between the academic program and external partnership like local industry, secondary schools, local government, local community, regional business incubator center, other educational institutions, alumni and industrial advisory council. The ongoing collaboration with external partners allows the program to prosper and grow.

Open access