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Given the importance of heat balance being maintained between a person and their environment an appropriate clothing choice is essential. Since military personnel are required to work effectively when deployed in any of the world's climates it is important that the thermal protection afforded by their clothing is considered as well as its more obvious protective properties such as those relating to the chemical and abrasive environments. Clothing descriptions restricted to details of heat and water vapour transfer characteristics alone, as is commonly the case, are recognised as being insufficient. Of particular note, where these data are obtained under 'artificial' conditions, ie intrinsic values, they are unlikely to represent the 'resultant' values as observed when worn by human subjects engaged in actual work tasks. Where intrinsic data are used in predictive standards calculations, to estimate safe work times etc, the workforce under consideration may not always be protected. One source of change in the thermal properties of clothing, when in the workplace, occurs due to increased convective and evaporative heat transfer at the wearer's skin surface caused by air movement through the clothing. This may occur as a result of wearer body movements or increased environmental air speed. The Ventilation Index has previously been suggested as an accurate and repeatable method for quantifying clothing ventilation characteristics. Although several other measurement techniques have also been suggested, the Ventilation Index is simple (albeit laborious) to conduct, and does not require the use of expensive equipment. Work conducted towards this thesis has shown that the Ventilation Index may be suitable for use in either manikin testing or human studies assessmentso f clothing. The aim of this thesis was to investigate the suitability of the Ventilation Index as a measurementt echnique for the assessmenot f clothing ventilation characteristics, particularly to consider the relationship between clothing ventilation and wearer physiological responses and to identify the factors which can affect this. The Ventilation Index measurement systems constructed as part of this research have improved on those used previously in similar research. New materials technology has provided an improved air-tight oversuit for use during measurement of the clothing micro-environment (a constant source of fiustration, it appears, for previous authors), while extensive calibration of the whole system has proved its accuracy. Using the Ventilation Index has shown that the ingress and egress of air into and from the clothing micro-environment may induce a physiological response from the wearer of the clothing (chapter 6) such increases in air movement being reflected by a drop in insulation afforded by the clothing (chapter 7). Of particular interest to persons involved in the thermal assessment of clothing, will be the suggestion that clothing may exhibit different ventilation characteristics when tested on a thermal manikin to when worn by human subjects. This difference appearing to be related to clothing fit (investigated in chapter 9). Of interest to wearer's of protective, is the observation that air-impermeable clothing does not necessarily withstand changes in environmental air movement (chapter 10). The technique is not without criticism. The standard tracer gas technique, used to calculate clothing air exchange rate, considers only air movement occurring next to the wearer's skin. In multi-layer clothing ensembles, the movement of air in clothing layers more distant will change the clothing micro-environment and thus have consequences for the wearer. Preliminary investigation suggests that distribution of nitrogen to each clothing layer should enable assessmenot fair movement in each of these layers.

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An experimental investigation exploring the use of wire mesh/hollow glass microsphere combination for use as thermal insulation was conducted with the aim to conclude whether or not it represents a superior insulation technology to those on the market. Three primary variables, including number of wire mesh layers, filler material, and temperature dependence were studied using an apparatus that was part of L.I.C.H.E.N (LabVIEW Integrated Conduction Heat Experiment Network), a setup whose basic components allow three vertically stacked samples to be thermally and mechanically controlled. Knowing the temperature profile in the upper and lower samples allows for determination of thermal conductivity of the middle material through the use of Fourier?s law. The numbers of layers investigated were two, four, six, and eight, with each separated by a metallic liner. The filler materials included air, s15, s35 and s60HS 3MTM hollow glass microspheres. The experiments were conducted at four temperatures of 300, 330, 366, and 400K with an interface pressure of 20 Psi. The experimental results indicated the ?number of layers? used was the primary factor in determining the effective thermal conductivity value. The addition of hollow glass microspheres as filler material resulted in statistically insignificant changes in effective thermal conductivity. Increasing the number of wire mesh layers resulted in a corresponding increase in effective thermal conductivity of the insulation. Changes in temperature had little to no effect on thermal conductivity. The effective thermal conductivity values for the proposed insulation structure ranged from 0.22 to 0.65 W/m-K, the lowest of which came from the two layer case having air as filler material. The uncertainties associated with the experimental results fell between 10 to 20 percent in all but a few cases. In the best performing cases, when compared with existing insulation technologies, thermal conductivity was approximately 3 to 10 times higher than these methods of insulation. Thus, the proposed insulation scheme with hollow glass-sphere filler material does not represent superior technology, and would be deemed uncompetitive with those readily available in the insulation market.

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The thesis is concerned with the theme of energy savings in the Building industry. It describes passive house development in detail with a focus on the construction part of buildings with low energy consumption. At first, there is an overview of the actual situation concerning the new European Union’s restrictions and a basic classification of energy efficient buildings is introduced. Further, construction compositions in two energy standards are designed for a few selected construction systems suitable for a passive house. They are evaluated from different points of view and compared to each other. Finally, an estimate of the passive house value is given as well as return of extra investments with regards to energy price increase. Key words The thesis is concerned with the theme of energy savings in the Building industry. It describes passive house development in detail with a focus on the construction part of buildings with low energy consumption. At first, there is an overview of the actual situation concerning the new European Union’s restrictions and a basic classification of energy efficient buildings is introduced. Further, construction compositions in two energy standards are designed for a few selected construction systems suitable for a passive house. They are evaluated from different points of view and compared to each other. Finally, an estimate of the passive house value is given as well as return of extra investments with regards to energy price increase. Key words The thesis is concerned with the theme of energy savings in the Building industry. It describes passive house development in detail with a focus on the construction part of buildings with low energy consumption. At first, there is an overview of the actual situation concerning the new European Union’s restrictions and a basic classification of energy efficient buildings is introduced. Further, construction compositions in two energy standards are designed for a few selected construction systems suitable for a passive house. They are evaluated from different points of view and compared to each other. Finally, an estimate of the passive house value is given as well as return of extra investments with regards to energy price increase.

The main objective of the thesis is to study the thermal properties of Si-based polymer derived ceramics (PDCs) at elevated temperatures and to classify the main factors affecting the thermal transport through these ceramics. The polymer derived ceramics with the chemistry Si- O-C-N were prepared starting from commercial polycarbosilane, polysiloxane, and polysilazane precursors. These precursors are cross-linked at room temperature to obtain the preceramic, followed by controlled pyrolysis (at different temperatures ranging from 1200 oC to 1800 oC in argon, nitrogen or carbon-di-oxide atmospheres), to get the final ceramic. The first part of the thesis discusses on development and studies of dense polymer derived thin disks having a basic chemistry, Si-C, Si-O- C, and, Si-C-N-O, developed via a casting technique followed by specific pyrolysis cycles. Having a thickness in the range of 100 μm- 300 μm, these ceramic disks were studied to be nanocrystalline/amorphous at least up to a temperature of 1400 oC and were found to have a significant amount of Cfree phase existing in them along with the intended chemistry. The high-temperature thermal properties were primarily investigated on ceramics prepared at a pyrolysis temperature of 1200 oC (ceramic still in nanocrystalline/amorphous glassy phase). The disks were found to have very low expansion coefficients (CTE) measured up to ~900 oC and the thermal diffusivity (k) and thermal conductivity (l) of these disks were also measured. An attempt to understand the influence of the different phases in a SiOC ceramic (mainly the Cfree phase, studied by enriching the carbon percentages using DVB) in determining the final thermal properties was also conducted. The influence of carbon enrichment on the mechanical properties of these disks is also studied as a sub-part of this work. The second part of the work deals with testing the possibility to use these ceramics for high-temperature insulation applications. ‘Reticulated’ ceramic foams of relatively same chemistries as that of the disks were prepared by a template replica approach, using polyurethane (PU) foams (more open-celled to more closed-celled types of PU foams were used in the study) as the template. Porous structures having densities ranging from as low as 0.02 g.cm-3 to 0.56 g.cm-3 and with a porosity ~ 80 % to ~99% were prepared and tested. The developed foams showed excellent thermal stability up to a temperature of 1400 oC and possessed very low thermal expansion. The thermal conductivity measured on them at RT gave values in the range 0.03 W.m-1.K-1- 0.25 W.m-1.K-1. A Gibson-Ashby modeling approach to explain the thermal conductivity of the porous ceramics was also attempted. The developed foams were also found to be mechanically rigid. In a nutshell, the thesis work studies the thermal properties of Si-O-C- N ceramics in detail and probes into the possibility to develop these class of Si-O-C-N ceramics into promising high-temperature insulation material.