Non-destructive structural analysis of the heat conducting path in power electronics and solid state lighting by thermal transient testing

Thermal transient testing is a tool for examining structural details of a heat conducting path composed of heat conduction and heat convection sections. Using the change of inherent heat in electronics, temperature transients provide a characterisation technique where using x-ray or acoustic microscopy would be troublesome and time-consuming. A complete toolkit for the accurate dynamic characterisation of subassemblies and cooling mounts is described in the paper. After giving the theoretical background, it is shown that the methodology can directly generate a valid and detailed structural equivalent from a single transient measurement. The descriptive thermal functions such as time constants and structure functions are demonstrated in practical examples, the capability of the structure functions for validating cooling concepts and detecting assembly problems is shown. Recognising the fact that systems with multiple energy transport such as electric energy converted to heat and light exhibit special features; the concept of structure functions has been modified for applications in solid state lighting.Papers presented at the 13th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Portoroz, Slovenia on 17-19 July 2017 .International centre for heat and mass transfer.American society of thermal and fluids engineers

Environmental drivers of forest biodiversity in temperate mixed forests – A multi-taxon approach

Harmonization of timber production and forest conservation is a major challenge of modern silviculture. For the establishment of ecologically sustainable forest management, the management-related environmental drivers of multi-taxon biodiversity should be explored. Our study reveals those environmental variables related to tree species diversity and composition, stand structure, litter and soil conditions, microclimate, landscape, and land-use history that determine species richness and composition of 11 forest-dwelling organism groups. Herbs, woody regeneration, ground-floor and epiphytic bryophytes, epiphytic lichens, terricolous saprotrophic, ectomycorrhizal, and wood-inhabiting macrofungi, spiders, carabid beetles, and birds were sampled in West Hungarian mature mixed forests. The correlations among the diversities and compositions of different organism groups were also evaluated. Drivers of organism groups were principally related to stand structure, tree species diversity and composition, and microclimate, while litter, soil, landscape, and land-use historical variables were less influential. The complex roles of the shrub layer, deadwood, and the size of the trees in determining the diversity and composition of various taxa were revealed. Stands with more tree species sustained higher stand-level species richness of several taxa. Besides, stands with different dominant tree species harbored various species communities of organism groups. Therefore, landscape-scale diversity of dominant tree species may enhance the diversity of forest-dwelling communities at landscape level. The effects of the overstory layer on forest biodiversity manifested in many cases via microclimate conditions. Diversity of organism groups showed weaker relationship with the diversity of other taxa than with environmental variables. According to our results, the most influential drivers of forest biodiversity are under the direct control of the actual silvicultural management. Heterogeneous stand structure and tree species composition promote the different organism groups in various ways. Therefore, the long-term maintenance of the structural and compositional heterogeneity both at stand and landscape scale is an important aspect of ecologically sustainable forest management

Tolerance of awake surgery for glioma : a prospective European Low Grade Glioma Network multicenter study

Background: Gross total removal of glioma is limited by proximity to eloquent brain. Awake surgery allows for intraoperative monitoring to safely identify eloquent regions. However, data on adverse psychological effects induced in these patients is limited. Objective: This study explored patients' perception of awake surgery for glioma, with special focus on intraoperative pain and anxiety. Methods: This study was conducted at five neurosurgical centers within the European Low Grade Glioma Network. Patients underwent awake surgery for glioma according to the protocol of the individual center. Pain and discomfort were measured during the awake phase. Postoperatively, patients answered a questionnaire on aspects of their operation. Results: One hundred five patients were enrolled. Pain levels on a 10-cm visual analogue scale were 1.3 cm at the beginning, 1.9 cm the middle, and 2.1 cm at the end of awake phase. Levels of anxiety were 2.2 cm, 2.5 cm and 2.6 cm, respectively. Women and patients younger than 60 years exhibited highest mean anxiety levels. The patient questionnaire revealed that the majority of patients feel comfortable with the procedure. Discomfort resulted from head fixation or positioning on the operating table. Conclusions: We demonstrate that awake surgery is well tolerated, as neither intraoperative nor postoperative assessment revealed major disadvantages. Concerning practical lessons learned from this study, we emphasize the importance of minimizing pain and preparing patients thoroughly to reduce anxiety and maximize cooperation. Awake surgery is an excellent treatment modality for brain tumors with very positive perception by patients

Polarimetric Optical Fiber Sensors for Dynamic Strain Measurement in Composite Materials

Polarimetric optical ber sensors possess possibility of temperature compensation, dynamic and integral system of strain monitoring, as well as low cost of photo-detecting elements. In the paper we present results of the sensor analysis with dierent kinds of birefringent optical bers leading to an optimal setup for dynamic strain monitoring in composite materials. A great attention is put on parameters of the light sources like coherence and width of spectrum and their inuence on dynamics of the strain sensor

Post-socialist Urban Ecosystems in Flux: The Socio-spatial Differentiation of Three Budapest Districts

This paper investigates the changing post-socialist patterns of social and environmental segregation in Budapest, through a case study of three of its inner-city districts. These quarters represent a north-south cross-section of the city, because they contain the northern edge of the mixed-use residential and commercial urban core of Budapest, in addition to a wider range of historical residential and industrial areas in the inner city, and former industrial suburbs. The paper also includes a review of the spatial structure of the human, built and natural components of the urban ecosystem at the onset of the transformation, with the aim of clarifying how socialist-era trends have influenced urban residential inequalities. This has been supplemented with an outline of the qualitative features and temporal trends of urban spatial ecological differentiation in the post-socialism. The concluding section of the paper outlines the policy issues related to the social and environmental problems observed in the given context