This paper deals with the evaluation of changes in hardness of magnesium alloys during precipitation hardening that are nowadays widely used in different fields of industry. It focuses exactly on AZ31, AZ61 and AZ91 alloys. Observing material hardness changes serves as an effective tool for determining precipitation hardening parameters, such as temperature and time. Brinell hardness measurement was chosen based on experimental needs. There was also necessary to make chemical composition analysis and to observe the microstructures of tested materials. The obtained results are presented and discussed in this paper.
Sandra Veličković, Slavica Miladinović, Blaža Stojanović, Ružica R. Nikolić, Branislav Hadzima and Dušan Arsić
Hybrid materials with the metal matrix are important engineering materials due to their outstanding mechanical and tribological properties. Here are presented selected tribological properties of the hybrid composites with the matrix made of aluminum alloy and reinforced by the silicon carbide and graphite particles. The tribological characteristics of such materials are superior to characteristics of the matrix – the aluminum alloy, as well as to characteristics of the classical metal-matrix composites with a single reinforcing material. Those characteristics depend on the volume fractions of the reinforcing components, sizes of the reinforcing particles, as well as on the fabrication process of the hybrid composites. The considered tribological characteristics are the friction coefficient and the wear rate as functions of the load levels and the volume fractions of the graphite and the SiC particles. The wear rate increases with increase of the load and the Gr particles content and with reduction of the SiC particles content. The friction coefficient increases with the load, as well as with the SiC particles content increase.
High quality is organizations’ competitive advantage. It is beneficial to base this on professional approach, and basic concepts and definitions with scientific foundation. The necessary main concepts consist of quality, quality management, quality improvement and quality assurance. Organizations’ top management is responsible of the quality management decisions and implementations. The present practical situation is fragmented and the implementations are most often based on the instrumental means of the different methodological schools, which is confusing and detrimental to the understanding and usefulness of the concept of quality management. It is not beneficial to build a special system for quality management by only following the requirements of the general standard. This cannot ensure competitive business advantage. In this article, we present an alternative approach that is a natural practical way to realize quality management as the teleological solution, Quality Integration, in which the general and specific quality concepts, principles and methodology are embedded within the normal business management activities. Our Quality Integration is based on the thinking of organizational learning. Its framework covers both running the current business and improving the overall business performance. This model has been used as the thinking framework in practical organizational cases since 1990’s. As the business circumstances change constantly, the organization must be constantly ready to renew through both small and radical changes. This change also receives resistance, and the development takes place according to a multi-phase process towards the new integration and requires a proper recognition and decisions. Principles of the organizational learning can help organizations in a consistent way. Evaluation of the overall organizational performance is an important quality management practice and should take into account performance enablers (processes) and also the results obtained thereof. In our approach, the evaluation criteria emphasize organizational learning and integration. The external context of the organization has a crucial role in achieving and developing the business objectives. The organization’s strategy can no longer be based on the value chains but on finding ways to alter them radically through value networking. The organization is influenced by the true and all-inclusive reality, which differs from the apparent reality perceived by the senses, and which is only revealed through consciousness. Understanding this reinforces awareness and trust that are important factors also in quality management and quality assurance.
Everyone, every day or almost every day, uses various type of services, without being even aware of it. They could have been both intangible and material services. Customers want to receive services of the highest quality, and service providers are looking for solutions to meet their requirements. They can analyze the quality of their services to indicate the strengths and weaknesses of these services to know what needs to be improved and what can be omitted. In the literature on the quality engineering, many methods that can be used in such a situation are described. In most cases, these methods are based on the differences between customers’ expectations for the service and the perception of the service which they received. In case of most of these method, there is a need of information from customers about research service, which means that they are involved in this process. In the paper five methods of quality service analysis, which are the most often used by service enterprises, were briefly characterizes to help readers to choose the most accurate one for them.
In this paper TPM and PAMCO coefficients were shortly characterised. On the basis of TPM coefficients its effectiveness was estimated. Thanks to using time and PAMCO coefficients, the utilization of working time machines was researched. Moreover, there a correlation between TPM coefficient and the quality level was examined. A histogram was drawn up in order to illustrate the distribution. The obtained results allowed to evaluate the effectiveness of the machine. The period of research embraced fifty-two weeks (1 year) and the object of the analysis is the injection moulding machine.
The inherent benefits of an accident prevention program are generally known only after an accident has occurred. The purpose of implementation of the program is to minimize the number of accidents and cost of damages. Allocation of resources to implement accident prevention program is vital because it is difficult to estimate the extent of damage caused by an accident. Accurate fatal accident predictions can provide a meaningful data that can be used to implement accident prevention program in order to minimize the cost of accidents. This paper forecast the fatal accidents of factories in India by using Auto-Regressive Integrating Moving Average Method (ARIMA) model. Accident data for the available period 1980 to 2013 was collected from the Labour bureau, Government of India to analyze the long term forecasts. Different diagnostic tests are applied in order to check the adequacy of the fitted models. The results show that ARIMA (0, 0, 1) is suitable model for prediction of fatal injuries. The number of fatal accidents is forecasted for the period 2014 to 2019. These results suggest that the policy makers and the Indian labour ministry must focus attention toward increasing fatal accidents and try to find out the reasons. It is also an opportunity for the policy makers to develop policies which may help in minimizing the number fatal accidents.
In this paper a model of service quality management based on the process approach has been presented. The first part of the article contains the theoretical framework of service quality and the process approach in management. Next, quality of service process has been presented in reference to a process-based definition in quoted literature. Finally, the outcomes of a customer questionnaire concerning the validity of particular quality attributes has been presented. The collected data in relation to service process quality stages have enabled the development of a of service quality model for process management.
The following paper concentrates on some problems resulting from the use of Quality Function Deployment method in industrial enterprises. It is not an easy task although the method itself has many advantages. The aim of the paper is to analyse basic international literature as well as the main advantages and limitations of the Quality Function Deployment
The implementation of road infrastructure projects often results in delays due to objective causes, with repercussions on the final execution deadline and with value implications. The use of critical path method for planning and the executin windows, will result in better time process management and optimization delays.
In this paper will be presented the influence of high temperatures on asphalt street pavement in terms of the influence of temperature on permanent deformations and thus the technical condition of the streets, comparable to the effects induced on extra-urban roads.
Environmental factors are one of the mayn factors being assaulted in operation and road structures are very important in terms of the influence they can have on the state road transport technical infrastructure.
Will be presented differences between urban road structures (streets) and extra-urban (road) both in terms of construction, the demands of traffic and environmental conditions to which they are subject.
Road structures extra-urban and urban areas are required differently in terms of the environmental conditions of the location ambient different thereof, that is, when the streets they are inside localities and the built environment significantly affect road infrastructure, unlike in the case of roads where they are located just outside the settlements, reducing the effect of air currents accumulation pavement surface temperature.
To demonstrate the influence of high temperatures on the pavement were conducted laboratory tests on asphalt mixtures in order to demonstrate the occurrence of reduction of physical characteristics, with adverse implications on the performance of applications similar to traffic.