Analysis on exergy consumption patterns for space heating in Slovenian buildings

Problem of high energy use for heating in Slovenian buildings is analyzed with exergy and energy analysis. Results of both are compared and discussed. Three cases of exterior building walls are located in three climatic zones in winter conditions. Results of energy analyses show that the highest heating energy demand appears in the case with less thermal insulation, especially in colder climate. If the comparison is made only on the energy supply and exergy supply, the results of exergy analysis are the same as those of energy analysis. The main difference appears, if the whole chain of supply and demand is taken into consideration. Exergy calculations enable us to analyze how much exergy is consumed in which part, from boiler to building envelope. They also reveal how much energy is supplied for the purpose of heating. Results show that insulation has much bigger effect than effect of boiler efficiency. However, the most effective solution is to improve building envelope together with boiler efficiency. Better thermal insulation also makes an important contribution to the improvement of thermal comfort conditions. It causes higher surface temperatures resulting in a larger warm radiant exergy emission rate and consequently better thermal comfort.     

Calculation of the mercury accumulation in the Idrijca River alluvial plain sediments

From the historic literature on the Idrija mercury mine, it is evident that part of the smelting and mining waste was dumped into the Idrijca River. This waste was transported downstream during floods. The amount of mercury which has accumulated in the alluvial sediments of the Idrijca River until the present was studied. Mapping of Holocene river terraces of the Idrijca River was performed in order to estimate the volume of the alluvial sediment. For the purpose of the assessment of the mercury concentration, we sampled the alluvial sediments on different levels and performed an analysis of variance. The greatest variability is between the floodplain and terraces inside the same alluvial plain. Considering this fact, which determined the methodology employed for calculation, we estimated that about 2029 tons of mercury is stored in the Idrijca River alluvial sediments.     

Daylight illuminance control with fuzzy logic

The purpose is to take full advantage of daylight for inside illumination. The inside illuminance and luminous efficacy of the available solar radiation were analyzed. The paper deals with the controlled dynamic illuminance response of built environment in real-time conditions. The aim is controlled functioning of the roller blind as a regulation device to assure the desired inside illuminance with smooth roller blind moving. Automatic illuminance control based on fuzzy logic is realized on a test chamber with an opening on the south side. The development and design of the fuzzy controller for the corresponding positioning of the roller blind with the available solar radiation as external disturbance is the subject of this paper.     

Effects of controlled nucleation on freeze-drying lactose and mannitol aqueous solutions

The lyophilization of lactose and mannitol aqueous solutions was investigated with an emphasis on analyzing the effects of controlled nucleation, temperature of nucleation, and pore size distribution on the freeze-drying process. The experimental procedure involved the depressurization technique of controlled nucleation, in-vial temperature measurements as well as measurements of the chamber pressure, which allowed the analysis of the product batch, loaded in the laboratory lyophilizator. The average pore enlargement was 93 and 58% with the incorporation of the controlled nucleation step in the lyophilization of 6?wt% lactose and 6?wt% mannitol solutions, respectively. Consequently, the primary drying times were lowered from 450 to 500?min in both cases. The pore sizes were determined to be as important as the solid material itself in the scope of the sublimation rates. Namely, the average equivalent diameter of the pores was larger in the dried mannitol cake compared to the lactose cake. However, despite the higher porosity of the dried mannitol cake, the end of the sublimation in the primary drying step was observed approximately 500?min earlier during the lyophilization of the lactose solution with the same initial concentration as the mannitol solution in a comparable freeze-drying protocol. In addition, an increase in mannitol concentration from 3 to 12?wt% was found to substantially extend the time required for the sublimation phase of the lyophilization.     

Tablet game-supported speech therapy embedded in children’s popular practices

Modern speech-language pathology practices (SLPPs) have adopted tablet games in recent years. Research is needed to take advantage of the potential benefits tablets can offer and to explore the factors that influence its introduction. This paper discusses a survey that was conducted to investigate the factors that influence speech-language pathologists’ (SLPs) beliefs and the actual use of tablets in SLPPs. The results of the survey, conducted among Slovenian SLPs, indicated that their most positive beliefs concerning tablets relate to social influence. Specifically, the beliefs relate to children’s interest and practice with tablets and have a significant impact on the decision-making of SLPs concerning introducing tablets in therapy. Conversely, SLPs’ most negative beliefs relate to the conditions for facilitating tablet use, particularly the lack of Slovenian applications. This paper discusses a separate case study that was conducted in which tablet game-supported therapy was introduced to a group of 44 children. The case study results indicated that the children accepted the use of tablet games for therapy purposes and the games had a positive impact on the children’s motivation and satisfaction.     

Facile Synthesis of Cu2ZnSnS4 Photovoltaic Absorber Thin Films via Sulfurization of Cu2SnS3/ZnS Layers

Copper zinc tin sulfide (Cu₂ZnSnS₄) has been receiving a lot of attention in recent years as a new, alternative absorber for the production of cheap thin film solar cells owing to the high natural abundance of all the constituents, its tunable direct-band-gap energy, and its large optical absorption coefficient. In addition, to overcome the problem of expensive vacuum-based methods, solution-based approaches are being developed for Cu₂ZnSnS₄ deposition. In this study, Cu₂ZnSnS₄ thin films were grown on soda lime glass substrates via the sulfurization of solution grown Cu₂SnS₃/ZnS stacked sulfide layers. A new facile route to overcome the difficulty of depositing Cu₂ZnSnS₄ thin film with a desired stoichiometric composition in a single cation solution has been presented. The influences of deposition cycles of layers on the morphological, compositional, structural, and optical properties of the samples were investigated. It was observed from scanning electron microscopy (SEM) images that the films were continuous and composed of homogenously distributed large grains. Possible chemical formulations of the best samples were predicted to be Cu_1.99Zn_1.25Sn_1.00S_3.76 and Cu_1.97Zn_1.03Sn_1.29S_3.71 via energy-dispersive X-ray spectroscopy (EDXS) results. The X-ray diffraction (XRD) patterns of the samples matched very well with the reference values. The Raman-scattering analysis of the films proved the phase purity of the CZTS samples. The optical absorption coefficient of the films was found to be about 10⁴ cm^?1 based on absorbance spectroscopy. The optical band gaps of the films were estimated to be between 1.36 and 1.50 eV. From these we are able to conclude that CZTS thin films can be effectively obtained via the vacuum-atmosphere sulfurization of Cu₂SnS₃/ZnS stacked sulfide layers.