Forecasting risks of natural gas consumption in Slovenia

Efficient operation of modern energy distribution systems often requires forecasting future energy demand. This paper proposes a strategy to estimate forecasting risk. The objective of the proposed method is to improve knowledge about expected forecasting risk and to estimate the expected cash flow in advance, based on the risk model. The strategy combines an energy demand forecasting model, an economic incentive model and a risk model. Basic guidelines are given for the construction of a forecasting model that combines past energy consumption data, weather data and weather forecast. The forecasting model is required to estimate expected forecasting errors that are the basis for forecasting risk estimation. The risk estimation strategy also requires an economic incentive model that describes the influence of forecasting accuracy on the energy distribution systems’ cash flow. The economic model defines the critical forecasting error levels that most strongly influence cash flow. Based on the forecasting model and the economic model, the development of a risk model is proposed. The risk model is associated with critical forecasting error levels in the context of various influential parameters such as seasonal data, month, day of the week and temperature. The risk model is applicable to estimating the daily forecasting risk based on the influential parameters. The proposed approach is illustrated by a case study of a Slovenian natural gas distribution company.     

Adjusting the Structure and Electronic Properties of Carbons for Metal‐Free Carbocatalysis of Organic Transformations

Carbon nanomaterials doped with some other lightweight elements were recently described as powerful, heterogeneous, metal‐free organocatalysts, adding to their high performance in electrocatalysis. Here, recent observations in traditional catalysis are reviewed, and the underlying reaction mechanisms of the catalyzed organic transformations are explored. In some cases, these are due to specific active functional sites, but more generally the catalytic activity relates to collective properties of the conjugated nanocarbon frameworks and the electron transfer from and to the catalytic centers and substrates. It is shown that the learnings are tightly related to those of electrocatalysis; i.e., the search for better electrocatalysts also improves chemocatalysis, and vice versa. Carbon–carbon heterojunction effects and some perspectives on future possibilities are discussed at the end.     

Examining the bentonite produced in a biodiesel refinery process as soil amendment in a well-draining soil

Clean Technologies and Environmental Policy - The expansion of biofuels produced from cooking oils and vegetal oils is expected to increase, together with the production of exhausted clay used in...     

Carrot DNA-methyltransferase is encoded by two classes of genes with differing patterns of expression

There is a wide variety of renal tubular disorders affecting children. Understanding the pathophysiology of each disease assists in the recognition and treatment of these diseases, which can have profound effects on a child's growth and development. We review some of the more common tubular disorders found in children, emphasizing those conditions in which recent advances have been made in understanding of the specific genetic or physiological defect responsible: Fanconi's syndrome, cystinuria, renal tubular acidosis, and the hypokalemic metabolic alkaloses. Current recommendations are presented for diagnosing and treating these conditions.     

Thermodynamic properties of the enzymatic hydrolysis of sunflower oil in high-pressure reactors

On the basis of our previous results, where optimal conditions for the lipase-catalyzed hydrolysis of sunflower oil in a high-pressure batch stirred tank reactor were determined, some thermodynamic and kinetic properties of lipase preparation Lipolase 100T (Aspergillus niger lipase) were established. Activation energy (32.7 kJ/mol) was determined from an Arrhenius plot. Activity of the Lipolase 100T increased between 35 and 50°C, but with further temperature increase thermal deactivation occurred. The thermal deactivation rate constant was 0.40, and the deactivation enthalpy was 123.0 kJ/mol. Because of the desirability of continuous applications of enzyme-catalyzed reactions, a high-pressure continuous flat-shape membrane reactor (HP CFSMR) was designed. Hydrolysis of sunflower oil in this reactor was performed. Maximal conversion in the HP CFSMR was achieved after 1 h. A polysulfone membrane was successfully used as a separation unit, and the highest conversion of FFA was determined at 50°C, 200 bar, and a flow rate for substrates of 0.1 mL/min (each).     

Nitrate removal from electro-oxidized landfill leachate by ion exchange

Treatment of landfill leachates by electrochemical oxidation led to the complete removal of chemical oxygen demand and ammonium nitrogen. However, as result of the ammonium oxidation, the partial formation of nitrate ions was observed. Ion exchange technology was investigated as a polishing step in the treatment of landfill leachates. Removal of nitrate from aqueous solutions was studied using two selective anion exchangers: Purolite A 520E and Purolite A 300, under a fixed bed configuration. The following aspects of the ion exchange system were experimentally analyzed: (i) the influence of the presence of other competitive anions in solution, sulfate and chloride, during the loading step, (ii) the breakthrough point and resin saturation as a function of chloride concentration in the feed stream and, (iii) the efficiency of the regeneration step working with NaCl solutions at several concentrations. After a comparison of the experimental results, it was concluded that the resin Purolite A 300 showed a better behavior. Experimental analysis of the equilibrium isotherms made it possible to determine the equilibrium constant (K=3.21) and the maximum capacity (q(max)=183mgg(-1)), important parameters in the design of the treatment process.     

Impact of open access on citation of scholarly publications in the field of civil engineering

The development of science is accompanied by growth of scholarly publications, primarily in the form of articles in peer-reviewed journals. Scientific work is often evaluated through the number of scientific publications in international journals and their citations. This article discusses the impact of open access (OA) on the number of citations for an institution from the field of civil engineering. We analyzed articles, published in 2007 in 14 international journals with impact factor, which are included in the Journal Citation Reports subject category “Civil Engineering”. The influence of open access on the number of citations was analyzed. The aim of our research was to determine if open access articles from the field of civil engineering receive more citations than non-open access articles. Based on the value of impact factor and ranking in quartiles, we also looked at the influence of the rank of journals on the number of citations, separately for OA and Non OA articles, in databases Web of Science (WOS), Scopus and Google Scholar. For 2,026 studied articles we found out that 22 % of them were published as OA articles. They received 29 % of all citations in the observed period. We can conclude by the significance level 5 % or less that in the databases WOS and Scopus the articles from top ranked journals (first quartile) achieved more citations than Non OA articles. This argument can be confirmed for some other journals from second quartile as well, while for the journals ranked into the third quartile it can’t be confirmed. This could be confirmed only partly for journals from the second quartile, and would not be confirmed for journals ranked into the third quartile. This shows that open access is not a sufficient condition for citation, but increases the number of citations for articles published in journals with high impact.     

Electroantennogram activity from antennae ofCeratitis capitata (Wied.) to fresh orange airborne volatiles

Twenty-six compounds have been identified from fresh orange airborne volatiles, the most abundant being limonene and alloaromadendrene. Ethyl- and butylhexanoates were found in middle concentrations, whereas the other compounds occur at low levels. Electroantennograms recorded fromCeratitis capitata Wied. (males and females) revealed limonene. butyl hexanoate, dihydrocarvone, and limonene oxide to be most active. In the case of dihydrocarvone, 4-ethyl acetophenone, and carvone, female antennae give greater responses than antennae of males. Limonene oxide was more active for males than females. Total airborne volatiles recovered from oranges elicited high EAGs, with females being more sensitive than males.