How Actors of Local Society (Community) Influence the Development of Decentralized General Education, and their Attitude to it.

AbstractOne of the most urgent problems is to find ways to involve local society in the development of general education in municipalities. One of the solutions is to increase the influence of local society on the decision-making processes of municipalities. The aim of the research is to find out the role of local society groups – students, their parents and principals – in the decision-making process, and their influence on the development of decentralized general education. The opinions of different actor groups are compared in order to find out their attitude to the decentralization processes of general education promoted by the LEA, and analyse the possible factors that influence the actor groups in the administrative decision-making processes which are used in the development of the LEA's policy and strategies.Quantitative and qualitative data collection methods are used – polls and profound interviews. The approach of the actor network theory is used in the research, which gives an opportunity to create an actor network for the decentralization process of general education. The most important actor groups in the process of decentralization have been identified. The results of the research show that in order to achieve the goals of development of general education, it is necessary to estimate the optimal degree of decentralization of educational management. The results of the research also show that sociological research gives substantial support to the planning of the development of general education towards decentralization and the achievement of the set aims

Energy and force analysis of Ti-6Al-4V linear friction welds for computational modeling input and validation data

The linear friction welding (LFW) process is finding increasing use as a manufacturing technology for the production of titanium alloy Ti-6Al-4V aerospace components. Computational models give an insight into the process, however, there is limited experimental data that can be used for either modeling inputs or validation. To address this problem, a design of experiments approach was used to investigate the influence of the LFW process inputs on various outputs for experimental Ti-6Al-4V welds. The finite element analysis software DEFORM was also used in conjunction with the experimental findings to investigate the heating of the workpieces. Key findings showed that the average interface force and coefficient of friction during each phase of the process were insensitive to the rubbing velocity; the coefficient of friction was not coulombic and varied between 0.3 and 1.3 depending on the process conditions; and the interface of the workpieces reached a temperature of approximately approximately 1273 K (1000 °C) at the end of phase 1. This work has enabled a greater insight into the underlying process physics and will aid future modeling investigations.EPSRC, Boeing Company, Welding Institut

High frequency linear friction welding.

Available from British Library Document Supply Centre-DSC:DXN015833 / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

A literature review of Ti-6Al-4V linear friction welding

Linear friction welding (LFW) is a solid-state joining process that is an established technology for the fabrication of titanium alloy bladed disks (blisks) in aero-engines. Owing to the economic benefits, LFW has been identified as a technology capable of manufacturing Ti-6Al-4V aircraft structural components. However, LFW of Ti-6Al-4V has seen limited industrial implementation outside of blisk manufacture, which is partly due to the knowledge and benefits of the process being widely unknown. This article provides a review of the published works up-to-date on the subject to identify the “state-of-the-art”. First, the background, fundamentals, advantages and industrial applications of the process are described. This is followed by a description of the microstructure, mechanical properties, flash morphology, interface contaminant removal, residual stresses and energy usage of Ti-6Al-4V linear friction welds. A brief discussion on the machine tooling effects is also included. Next, the work on analytical and numerical modelling is discussed. Finally, the conclusions of the review are presented, which include practical implications for the manufacturing sector and recommendations for further research and development. The purpose of this article is to inform industry and academia of the benefits of LFW so that the process may be better exploited

Economic and Employment Effects of Microloans in a Transition Country

Over the last years, microloans to small and medium-sized enterprises have grown in significance in many countries of Central and Eastern Europe. Empirical evidence on the economic and social impact of microfinance is, however, scant. In trying to shed more light on this important issue, this paper uses a case study and analyzes the economic impacts of the microloan programme of the Latvian development bank Hipoteku Banka. We analyse a dataset provided by the Hipoteku Banka and use economic indicators of Latvia and its regions as comparisons. We find that the firms that were granted a loan from Hipoteku Banka on average considerably increased their employment during the loan period. In addition, a survey was carried among the clients of the bank. The survey results imply that the microloan program made a clear contribution to supporting existing firms and establishing new businesses, although the impact varies across sectors of economic activity

A Study of the Reinforcement Effect of MWCNTs onto Polyimide Flat Sheet Membranes

Polyimides rank among the most heat-resistant polymers and find application in a variety of fields, including transportation, electronics, and membrane technology. The aim of this work is to study the structural, thermal, mechanical, and gas permeation properties of polyimide based nanocomposite membranes in flat sheet configuration. For this purpose, numerous advanced techniques such as atomic force microscopy (AFM), SEM, TEM, TGA, FT-IR, tensile strength, elongation test, and gas permeability measurements were carried out. In particular, BTDA–TDI/MDI (P84) co-polyimide was used as the matrix of the studied membranes, whereas multi-wall carbon nanotubes were employed as filler material at concentrations of up to 5 wt.% All studied films were prepared by the dry-cast process resulting in non-porous films of about 30–50 μm of thickness. An optimum filler concentration of 2 wt.% was estimated. At this concentration, both thermal and mechanical properties of the prepared membranes were improved, and the highest gas permeability values were also obtained. Finally, gas permeability experiments were carried out at 25, 50, and 100 ◦C with seven different pure gases. The results revealed that the uniform carbon nanotubes dispersion lead to enhanced gas permeation properties

Prediction of residual stress within linear friction welds using a computationally efficient modelling approach

Modelling the mechanical mixing occurring at the interface of a linear friction weld (LFW) is complex, making it difficult to study the development of residual stresses within real engineering workpieces. To address this, a sequentially-coupled numerical model of a Ti-6Al-4V LFW was developed, bypassing the modelling of the oscillations by applying the heat at the weld interface and sequentially removing rows of elements to account for the burn-off. Increasing the rubbing velocity was found to numerically increase the peak of residual stress while narrowing the distribution. Only small changes arose from increasing the applied pressure or changing the oscillation direction. Predictions suggested a strong correlation between the phase 3 temperature profile and the residual stress field subsequently created. Validation against neutron diffraction and contour method are also presented. This approach provides a computationally efficient technique to study the residual stress development within large 3D structures

The effect of micro-swinging on joint formation in linear friction welding

A 3D Eulerian numerical model was developed to investigate the effect of micro-swing on joint formation during workpiece oscillation in linear friction welding (LFW). The temperature field and axial shortening history for different amplitudes of micro-swing have been studied. Results show that the amplitude of micro-swing influences flash morphology and axial shortening. The micro-swing contributes to the extrusion of viscoplastic metal and the formation of flash during the LFW process. Flash volume and axial shortening increase as the amplitude of micro-swing becomes larger. When the amplitude of micro-swing is more than a critical value, a sudden change of axial shortening (different from the period of the oscillation cycle) would occur at certain welding time, which change would also have a periodic nature. Although different amplitudes of micro-swing affect joint morphology, the inner temperature field and the highest temperature of joints remain constant. The high temperature region inside the joints remains about the same, when the amplitude of micro-swing is constant. This indicates that the heat generated through plastic deformation could maintain the welding process, and so that the welding process would enter the equilibrium phase

Linear friction weld process monitoring of fixture cassette deformations using empirical mode decomposition

Due to its inherent advantages, linear friction welding is a solid-state joining process of increasing importance to the aerospace, automotive, medical and power generation equipment industries. Tangential oscillations and forge stroke during the burn-off phase of the joining process introduce essential dynamic forces, which can also be detrimental to the welding process. Since burn-off is a critical phase in the manufacturing stage, process monitoring is fundamental for quality and stability control purposes. This study aims to improve workholding stability through the analysis of fixture cassette deformations. Methods and procedures for process monitoring are developed and implemented in a fail-or-pass assessment system for fixture cassette deformations during the burn-off phase. Additionally, the de-noised signals are compared to results from previous production runs. The observed deformations as a consequence of the forces acting on the fixture cassette are measured directly during the welding process. Data on the linear friction-welding machine are acquired and de-noised using empirical mode decomposition, before the burn-off phase is extracted. This approach enables a direct, objective comparison of the signal features with trends from previous successful welds. The capacity of the whole process monitoring system is validated and demonstrated through the analysis of a large number of signals obtained from welding experiments