Parametric CFD Thermal Performance Analysis of Full, Medium, Half and Short Length Dimple Solar Air Tube

In the present decade, research regarding solar thermal air heaters (SAHs) has noticed a continuous progression in thermo-hydraulic performance augmentation approaches. There now exists a wide variety of thermo-hydraulic performance augmentation approaches and researchers have designated various structures. Nevertheless, there seems to be no generalization to any of the approaches employed. The present numerical investigation reports on the thermo-hydraulic characteristics and thermal performance for flow through a varied length (full, medium, half, and short length) dimple solar air heater (SAH) tube. The study highlights recent developments on enhanced tubes to augment heat transfer in SAH. The influence of different length ratio, dimple height ratio (H), and pitch ratio (s) on thermo-hydraulic characteristics have been investigated in the Reynolds number (Re) range from 5000 to 25,000. Air is used as the working fluid. The commercial software ANSYS Fluent is used for simulation. The shear stress transport (SST) model is used as the turbulence model. Thermal energy transport coefficient is increased in the full-length dimple tube (FLDT), compared to the medium-length dimple tube (MLDT), half-length dimple tube (HLDT) and short-length dimple tube (SLDT). Similarly, the pitch ratio (s) has more influence on Nusselt number (Nu) compared to the dimple height ratio (H). The friction factor decreases with an increase in pitch ratio. Nu increases and f decreases with increasing Re for all combinations of H and s. Low s and higher H yields high enhancement of HT and PD. Integration of artificial roughness on the tube increases the values of Nu and f by 5.12 times and 77.23 times for H = 0.07, s = 1.0 at Re value of 5000 and 25,000, respectively, in regard to the plain tube. For all the tested cases, the thermo-hydraulic performances (η) are greater than unity.

Сlassification culture of the Russia

Classification culture – a set of achievements of the country in the field of classification systems (CS): the study of their history and theory, the creation of own systems and the development of foreign experience, publications and options, practice of application. It is told about the achievements of Russia: works on the history of library CS, the directions of theoretical studies. For example, he CS history is well studied – from ancient times to the present day. Interesting CS were developed in the 18–19th century (for the largest and some university libraries). Schedules of the foreign CS – complete translation of the Colon Classification and the Dewey Decimal Classification into Russian was published. Published Russian UDC retranslation in 10 volumes. The country has CS, recognized by the international community as the National System of Russia (firstly published in the years 1961–1968 in the 30 books). Contemporary classification practice is distinguished by the presence of variants of schedules – full, medium and abridged, in book and machine-readable form. The experience of developing classification schedules for children's and school libraries is unique. The conclusion is made: Russia certainly has a high level of classification culture.

Effect of aminoacids on the fungicidal activity of quaternary ammonium salts

Amphipatic compounds exhibit an antimicrobial action both on bacteria and fungi. It is caused by a penetrative property of hydrophobic carbon chain of the compuound into a plasma membrane as well as by additional interaction of membrane elements and a hydrophilic amphipathic compound head. Bactericidal and fungicidal activity of this compound strongly depends on chemical environmental factors. In general, microorganisms are not as sensitive in a full medium as in a minimal one and the level of sensitivity rises when the amphipatic compounds are presend in destilled water. Similarly, the sensitivity is stronger in fluid than on solid medium. Our researches revealed however that some aminoacids, although they are complex organic compounds, increase the microbial sensitivity to some tested compound. This efect depends on a microorganism and on a kind of compound. The highest hipersensitivity has been observed against yeast-like fungi when arginine was a cooperating aminoacid. The effect concerns <em><em>Trichosporon</em> but not <em>E.coli</em>, not occurs in relation to SDS, quaternary ammonium salt IA, and bisammonium salts. Certainly the effect exhibit QAS, which have simple composition of hydrophilic „head” consisting only of methyl group, attaching to alkilic chain possessing keton group, build of 14 or 16 carbon atoms.

Glucose induces autophagy under starvation conditions by a p38 MAPK-dependent pathway

Autophagy is a natural process of ‘self-eating’ that occurs within cells and can be either pro-survival or can cause cell death. As a pro-survival mechanism, autophagy obtains energy by recycling cellular components such as macromolecules or organelles. In response to nutrient deprivation, e.g. depletion of amino acids or serum, autophagy is induced and most of these signals converge on the kinase mTOR (mammalian target of rapamycin). It is commonly accepted that glucose inhibits autophagy, since its deprivation from cells cultured in full medium induces autophagy by a mechanism involving AMPK (AMP-activated protein kinase), mTOR and Ulk1. However, we show in the present study that under starvation conditions addition of glucose produces the opposite effect. Specifically, the results of the present study demonstrate that the presence of glucose induces an increase in the levels of LC3 (microtubule-associated protein 1 light chain)-II, in the number and volume density of autophagic vacuoles and in protein degradation by autophagy. Addition of glucose also increases intracellular ATP, which is in turn necessary for the induction of autophagy because the glycolysis inhibitor oxamate inhibits it, and there is also a good correlation between LC3-II and ATP levels. Moreover, we also show that, surprisingly, the induction of autophagy by glucose is independent of AMPK and mTOR and mainly relies on p38 MAPK (mitogen-activated protein kinase).

Hypothesis on the Control of D 1 Protein Turnover by Nuclear Coded Proteins in Chlamydomonas reinhardtii

A hypothesis is presented on the events in the degradation of the D 1 protein of photosys­tem II in the light. It proposes the existence of a nuclear encoded cleavage system that is turning over and which is modulated by its phosphorylation state. A new experimental approach is presented in which the D 1 protein degradation under photoinhibitory light is tested in Chlamydomonas reinhardtii grown under phosphate deficiency and pretreated with cyclo-heximide. Under these conditions the degradation of the D 1 protein is delayed whereas in Chlamydomonas reinhardtii grown in full medium the D 1 protein is rapidly disappearing in high light upon addition of chloramphenicol (CAP) or lincomycin for inhibiting the resynthesis of the D 1 protein . Cycloheximide (CHI) has little effect on photoinhibition in such control cells. In cells grown, however, for 20 h in phosphate deficiency - such that there is not yet loss of photosynthesis capacity -pretreatment with cycloheximide or canavanine in low light the degradation of the D 1 protein even in 6 h high light is prevented to an appreciable extent. Further addition of CAP or lincomycin has only a small effect. [14C]leucine incorporation was used to show that there is no resynthesis and that the presence of the D 1 protein is due to a delay of degradation. The results are interpreted to show that excess high light which converts the D 1 protein into a potentially, degradable mode is not sufficient for degradation of the D 1 protein. A cleavage system is needed as well. It is postulated that under phosphate deficiency and pre-treatment with CHI or canavanine a nuclear coded cleavage system for the D 1 protein is depleted, i.e. the cleavage system for the rapidly turning over D 1 is also turning over. It is shown that under phosphate deficiency an alkaline phosphatase activity in the chloroplast and the thylakoid membrane of Chlamydomonas reinhardtii is increased. It is proposed that the ratio of kinase/phosphatase converts an active, stable phosphorylated cleavage system into a labile unphosphorylated and turning over state

Iron deficiency and the growth of pea roots

Pea roots have been cultured in sterile media in the presence and in the absence of added iron, and the effects of deficiency have been studied in three series of experiments. In the first, roots grown in deficient and full nutrient media were taken at intervals and on each sample growth and metabolic measurements were made. In the second, roots in which the earliest growth effects of deficiency had been observed were dissected into successive centimetre segments and metabolic and growth measurements were made on the separate fragments. In the third series of experiments the effects have been analyzed of transferring a root from a deficient medium in which growth had ceased to a full medium. It has been shown that after culture for 7 days in the deficient medium, increases in length and number of cells virtually cease; after this stage also the increase in respiration is relatively small. On the other hand protein continues to increase throughout the whole cultured period of 11 days. Oxygen absorption has been analyzed into a cyanide insensitive and a cyanide sensitive fraction, and it has been found that in the absence of iron, whereas the cyanide insensitive fraction increases continuously from the third to the eleventh day, the sensitive fraction ceases to increase after the seventh day. When roots in which growth has ceased were transferred to a full medium growth was resumed. The deficient roots were therefore not moribund. The arrest in growth is due to an abrupt cessation in division that occurs at about 7 days, and all the evidence indicates that this is the result of a disturbance confined to the meristem. The arrest in division cannot be attributed to an inhibition in the synthesis of protein. Evidence is presented which shows that in normal circumstances amino acids are probably synthesized in expanding or mature zones of the root, that they are carried forward in a polar translocation stream, and that they condense with the formation of proteins in cells that are being formed by meristematic activity. In the absence of iron division ceases, but the synthesis of amino acids continues. The sumps into which these acids are normally discharged are no longer provided, and they therefore tend to condense to proteins in the more mature cells adjacent to the apex. The cyanide-sensitive fraction of respiration is attributed to the activity of a cytochrome oxidase system. There is little or no further increase in this system after the time at which division ceases, and the coincidence may indicate a causal relation between the two events. But at the time when division ceases the cytochrome system is apparently normal in the apex and adjacent regions of the root. Therefore, if the cessation of division is due to arrest in the synthesis of cytochrome the position would be that a minimal quantity of cytochrome is required in the formation of a cell, and that when the supply of labile iron has been reduced to the level at which this minimal quantity cannot be provided then division ceases. This interpretation is consistent with the observation that the cessation of division is abrupt. The evidence, however, is not sufficiently extensive to warrant this conclusion, and the data do not exclude the alternative hypothesis that the depression in cytochrome synthesis is a consequence of the arrest in division.