Isothermal storage of solar energy in building construction

The role of advanced isothermal heat storage systems in buildings is discussed. A storage system encapsulated with phase change materials in which energy is absorbed in the hot period and released in the cold period is analyzed. The thermal behaviour of isothermal heat storage composites is examined using numerical techniques.Two methods of heat transfer with latent heat storage are described in the first part. Based on the initial results, the “effective heat capacity” method was selected and implemented into ESP-r. Numerical studies on the effect of isothermal storage of solar energy in specific building material components are discussed in the second part. Numerical simulations were conducted for two cases of multi-zone, highly glazed and naturally ventilated passive solar buildings. PCM-impregnated gypsum plasterboard was used as an internal room lining in the first case study and transparent insulation material combined with PCM was applied for the external south-oriented wall in the second case study. The behaviour of a TIM–PCM wall and its influence on the internal surface temperature are estimated. Air, surface and resultant temperatures are compared with a “no-PCM” case for both case studies and the diurnal and the seasonal latent heat storage effect is analyzed.     

Targeting of phosphonoacetate to the liver: Synthesis of a phosphonoacetate—trilactoside conjugate

As part of continuing studies on drug delivery to the human liver, a phosphonoacetate—trilactoside conjugate ( 12 ) has been synthesized in an overall yield of 23%. The shortness of the synthesis of this conjugate hinges upon a successful Michaelis—Arbuzov reaction of bromoacetamide 8 with tris-(trimethylsilyl) phosphite.     

Comparative Study of the Genetic and Biochemical Variability of Polyscias filicifolia (Araliaceae) Regenerants Obtained by Indirect and Direct Somatic Embryogenesis as a Source of Triterpenes

Polyscias filicifolia (Araliaceae) is broadly used in traditional medicine in Southeast Asia due to its antimicrobial, immunomodulating and cytotoxic activities. The main groups of compounds responsible for pharmacological effects are believed to be oleanolic triterpene saponins. However, Polyscias plants demonstrate relatively slow growth in natural conditions, which led to applying a developing sustainable source of plant material via primary (PSE), secondary (DSE) and direct somatic embryogenesis from DSE (TSE). The AFLP and metAFLP genotyping resulted in 1277 markers, amplified by a total of 24 pairs of selective primers. Only 3.13% of the markers were polymorphic. The analysis of variance showed that the PSE and TSE regenerants differed only in terms of root number, while the DSE plantlets differed for all studied morphological characteristics. Further, the chemical analysis revealed that oleanolic acid (439.72 µg/g DW), ursolic acid (111.85 µg/g DW) and hederagenin (19.07 µg/g DW) were determined in TSE regenerants. Our results indicate that direct somatic embryogenesis ensures the production of homogeneous plant material, which can serve as a potential source of triterpene compounds. Plants obtained via somatic embryogenesis could also be reintroduced into the natural environment to protect and preserve its biodiversity.     

Mn and other magnetic impurities in GaN and other III–V semiconductors – perspective for spintronic applications

III–V semiconductors doped with magnetic ions have been attracting interest of many laboratories all over the world during more than thirty years. At the beginning the reason was the will to understand influence of omnipresent unintentional, as well as intentionally introduced, impurities of transition metals or rare earths on electrical and optical properties of semiconductors commonly applied in electronic and optoelectronic devices. In the last years the subject of III–V semiconductors highly doped with magnetic ions, the so-called diluted magnetic semiconductors, has revived rapidly again in the context of the newborn branch of electronics, called spintronics. Diluted magnetic semiconductors based on III–V compounds are regarded as prospect candidates for applications in spintronic devices. The results of studies performed on III–V semiconductors, doped or diluted with different magnetic ions, are presented. Special attention is put to GaN because of a strong hope, based on theoretical calculations, for high temperature ferromagnetism. Reasons for difficulties with obtaining high temperature ferromagnetic semiconductors are shown. A possible mechanism of magnetic ordering in III–V semiconductors doped with Mn is presented.     

Effect of polythiourethane hardener modification on the behaviour of epoxy resin

Polythiourethanes based on oligomeric polymercaptans were employed as curing agent of epoxy resin. The epoxy matrices, in the form of castings, were characterized for their mechanical properties such as tensile strength, elongation at break and unnotched Charpy impact strength as per ISO methods. Mechanical studies indicated that the incorporation of polythiourethane into epoxy resin improves the toughness and flexibility with reduction in tensile strength for samples cured at ambient conditions and influences the mechanical and thermal properties according to its percentage content for samples cured at 130°C. The high increase of impact strength was explained by the development of two-phase morphology during the cure process. The results of this study indicate that both the stoichiometry of the curing mixture and the initial thermal condition are of critical importance in governing the curing mechanism, structure of the network, morphology and the final properties of epoxy/polythiourethane compositions.     

Prognostic Impact and Functional Annotations of KIF11 and KIF14 Expression in Patients with Colorectal Cancer

Genomic instability (GIN) has an important contribution to the pathology of colorectal cancer (CRC). Therefore, we selected mitosis and cytokinesis kinesins, KIF11 and KIF14, as factors of potential clinical and functional value in CRC, as their aberrant expression has been suspected to underlie GIN. We examined the expression and the prognostic and biological significance of KIF11 and KIF14 in CRC via in-house immunohistochemistry on tissue microarrays, public mRNA expression datasets, as well as bioinformatics tools. We found that KIF11 and KIF14 expression, at both the protein and mRNA level, was markedly altered in cancer tissues compared to respective controls, which was reflected in the clinical outcome of CRC patients. Specifically, we provide the first evidence that KIF11 protein and mRNA, KIF14 mRNA, as well as both proteins together, can significantly discriminate between CRC patients with better and worse overall survival independently of other relevant clinical risk factors. The negative prognostic factors for OS were high KIF11 protein, high KIF11 protein + low KIF14 protein, low KIF11 mRNA and low KIF14 mRNA. Functional enrichment analysis revealed that the gene sets related to the cell cycle, DNA replication, DNA repair and recombination, among others, were positively associated with KIF11 or KIF14 expression in CRC tissues. In TCGA cohort, the positive correlations between several measures related to GIN and the expression of KIFs were also demonstrated. In conclusion, our results suggest that CRC patients can be stratified into distinct risk categories by biological and molecular determinants, such as KIF11 and KIF14 expression and, mechanistically, this is likely attributable to their role in maintaining genome integrity.     

Double criterion optimisation of transparent fa?ades based on solar thermal processes

This work aimed to find the best possible solution for transparent fa?ades. The evaluation was formulated to assure the highest user comfort criteria corresponding to energy efficiency—two criterion optimisation. The analyses were based on BESTEST, south-oriented zone geometry. Computer model was designed using Finite Control Volume Techniques with assumptions for applied materials and specified boundary conditions, plus reference year for energy calculation (WYEC2). The natural ventilation fa?ade system was designed to determine airflow network inside thefa?ade. The adjustable size of openings(inlets and outlets)was selected at the level of 80% for the cold season and totally closed during the hot season. Environmental parameters for thermal comfort evaluation were: zone resultant temperature and solar radiation in zone space. Energy efficiency was assessed based on heat flux between the zone with controlled temperature and external environment. Results showed that well selected design of buffer zone section could improve energy efficiency of adjacent zones for both winter and summer periods. The most profitable Double Skin fa?ade solutionis DGC (double glazing with lowe coating) combined with single glazing with internal blinds (SGB) or coloured glazing.     

PATTERN FORMATION IN SOLID FILM GROWTH DURING CVD

This paper deals with the evolution of a gas-solid interface during growth of amorphous CVD films. The aim of the analysis is to show that a comprehensive gas-solid CVD model may simplify significantly under conditions of two limiting cases: kinetic and diffusion-limited growth. The linear stability behavior of the simplified model was found to be almost identical to that of the original and more comprehensive model. It was found that planar film growth was inherently stable under kinetically controlled deposition conditions, but under diffusion-limited conditions, planar film stability depended on the magnitude of the dimensionless group 9Pe, which represents a Damkdhler number of deposition. Numerical solution of the simplified model showed that an increase in 9pe adversely affected the uniformity of film deposition. Predicted morphological phenomena were found to be very similar to experimental observations (Viljoen, et al,1994).     

Influence of forward and multiple light scatter on the measurement of beam attenuation in highly scattering marine environments

Using three-dimensional Monte Carlo radiative transfer simulations, we examine the effect of beam transmissometer geometry on the relative error in the measurement of the beam-attenuation coefficient in an aquatic environment characterized by intense light scattering, especially within submerged bubble clouds entrained by surface-wave breaking. We discuss the forward-scattering error associated with the detection of photons scattered at small angles (< 1 degrees) and the multiple-scattering error associated with the detection of photons scattered more than once along the path length of the instrument. Several scattering phase functions describing bubble clouds at different bubble void fractions in the water are considered. Owing to forward-scattering error, a beam-attenuation meter (beam transmissometer) with a half-angle of receiver acceptance of 1.0 degrees and a path length of 0.1 m can underestimate the true beam attenuation within the bubble cloud by more than 50%. For bubble clouds with a beam attenuation of as much as 100 m(-1), the multiple-scattering error is no more than a few percent. These results are compared with simulations for some example phase functions that are representative of other scattering regimes found in natural waters. The forward-scattering error for the Petzold phase function of turbid waters is 16% for a typical instrument geometry, whereas for the Henyey-Greenstein phase function with the asymmetry parameter of 0.7 and 0.9 the error range is 8-28%.