Browse

51 - 60 of 1,729 items :

  • Chemical Engineering x
Clear All

Abstract

This article presents a method for the quick assessment of the safety of the road on an active landslide on the Just mountain at Tęgoborze using the landslide hazard ratio of landslide movements. The hazard indicator for landslide traffic has been defined as the quotient of the largest displacements obtained from measurements using a terrestrial laser scanner to the largest displacement obtained from a numerical model of the worst geotechnical conditions and an unstable landslide. The application of this indicator was presented on the example of national road No. 75 along the section of the road in km from 51 + 900 to 52 + 700 at the location of the Just mountain at Tęgoborze in the south of Poland. The road is located on an active landslide and has a lot of traffic. The measurements were conducted with the RIEGL. VZ400 terrestrial laser scanner from 2012 to 2016. As a result of the measurements performed with a terrestrial laser scanner, a cloud of 3D points was obtained. Differential models of subsequent measurements were constructed and compared to the first base measurements. The results of 3D differential models obtained from terrestrial laser scanner measurements were compared with results obtained from 3D numerical modelling. Numerical calculations were conducted assuming the worst geotechnical conditions. The model of the landslide was fully saturated. A numerical simulation computed using the finite element method (FEM) in the MIDAS GTS program was applied. A result of the safety factor F = 0.8 (i.e. an unstable landslide) was obtained. In order to estimate the hazard, the values of the landslide hazard indicator were determined for each date using the measurements conducted with the laser scanner.

Abstract

Fly ash and slag were examined for the removal processes of Pb(II) ions from water in batch experiments under different conditions of adsorbent dosage, initial concentration, pH and contact time. The materials are industrial waste generated from the high temperature treatment of sewage sludge by the circulating fluidized bed combustion (CFBC) technology. Physical and chemical properties, as well as adsorption efficiency and calculated maximum adsorption capacity of Pb(II) ions were determined using a variety of methods. The kinetic analysis revealed that the adsorption process is better described by the pseudo-second order equation and it is well fitted to the Freundlich model.

Abstract

Zakopane is a regional tourist city that is unique on the national scale. It is a one of a kind mountain resort with an exceptional history and atmosphere. It is a fashionable place where visitors can both rest and test themselves. It currently requires not only sustainable development but also that the effects of negligence and its deficiencies in spheres required for it to comfortably function be addressed, in addition to the supplementation of its offering both in terms of use and culture. The small-scale architecture of the Podhale region must rise to contemporary challenges. Presenting underground projects from all over the world aids in raising awareness as to the development potential of the area, demonstrating one of the paths to solving the problems of overburdened cities. Examples show means of relieving the pressure of current needs, simultaneously relieving the above-ground service programme of cities and increasing the amounts of greenery at their disposal.

Abstract

This paper is an attempt at reconstructing Stanisław Witkiewicz’s creative method on the basis of his scattered writings. The Zakopane style has become a phenomenon across a broad spectrum of Polish national styles. The inspirations for classical national styles were typically arbitrarily selected sets of forms taken from a specific historical style associated with a given nation or state. It was often an eclectic set – enriched with elements derived from other styles. Stanisław Witkiewicz consistently avoided borrowing and copying, confining himself solely to drawing inspiration from the folk art of Podhale. In the methodology of his architecture, rational elements (exposing the structure, stressing hygiene) interweaved with ornamentation, predominantly featuring floral themes and elements of a specific mythology.

Abstract

Magnesium based alloys are very promising material to be used mainly for biodegradable implants in medical applications. However, due to their very low corrosion resistance in the environment of in vivo is their use limited. Increase of the corrosion resistance of magnesium alloys in vivo can be achieved, for example, by a suitable choice of surface treatment while the biocompatibility must be ensured. Fluoride conversion coatings meet these requirements. Unconventional fluoride conversion coating was prepared on ZE41 magnesium alloy by dipping the magnesium alloy into the Na[BF4] salt melt at 450 °C for 0.5; 2 and 8 h. The morphology and thickness of the prepared fluoride conversion coatings were investigated as well as the corrosion resistance of the treated and untreated ZE41 magnesium alloy specimens. The corrosion resistance of the untreated and treated ZE41 magnesium alloy was investigated using electrochemical impedance spectroscopy in the environment of the simulated body fluids at 37 ± 2 °C. The obtained results showed a positive influence of the fluoride conversion coating on the corrosion resistance of the ZE41 magnesium alloy.

Abstract

This study was conducted to identify the most deleterious nonsynonymous single nucleotide polymorphisms (nsSNPs) in the ovalbumin gene family, including OVALX, OVALY, and OVAL genes, which are involved in the synthesis of the most important components in the chickens’ eggs using a comprehensive in silico approach. Ten different computational servers were utilized to prioritize the possible deleterious effects of the retrieved nsSNPs in terms of structure, function, and stability. Results indicated entirely damaging effects of H365P in OVALX, I167T in OVALY, and V209G, L231P, F307C, and S317P in OVAL proteins. Further prediction tools showed that all of these deleterious nsSNPs were positioned in variable locations within several α-helix motifs in all studied ovalbumin proteins. Furthermore, all witnessed nsSNPs were predicted to be resided in the receptors binding sites, signifying remarkable involvement of such nsSNPs in damaging of the altered proteins. In conclusion, the present study provides the first inclusive data with regard to the most deleterious nsSNPs in OVALX, OVALY and OVAL genes in chickens. The present bioinformatics data may be useful for breeders who intend to raise chickens for egg production, in such a way the presence of any of these deleterious nsSNPs in any selected breed may possess several damaging effects on the egg components, which may impair egg production. Therefore, it can be stated that breeders have to confirm the absence of any of these deleterious nsSNPs before being proceeded further for large-scale egg-production purposes.

Abstract

Methylxanthines such as caffeine, theophylline, theobromine are significant and widespread psychoactive substances. We developed the isocratic method with optimum composition of the mobile phase 90 % water: 10 % acetonitrile and confirmed repeatability of retention times and peak areas. The developed HPLC method was applied to determine the content of methylxanthines in selected types of black and green teas available on the market. Of the black teas (tea bags), the highest concentration of theobromine was found in Ceylon tea (18.98 mg.L−1). The highest concentration of caffeine was in a cup of Earl Gray tea (254.09 mg.L−1). Among loose black teas, the highest content of both theobromine and caffeine was found in Pu Erh Superior tea, where the theobromine content was 24.62 mg.L−1 and the caffeine content was 520.67 mg.L−1. Of green powder teas, highest caffeine content (306.46 mg.L−1) was in Shizuoka Matcha Premium and the highest content of theobromine (8.45 mg.L−1) was found in GABA Midori. From the loose green tea, the highest concentration of theobromine (12.85 mg.L−1) was in Lung Ching West Lake. The highest caffeine content (484.85 mg.L−1) was in Gyokuro Shizuoka Premium Tea. In both types of teas the amount of theobromine and caffeine was quantified, but the presence of theophylline was not proven. Data on contents of these metabolites in tea products are highly informative for consumers.

Abstract

Parabens are synthetic preservatives that are used on a large scale in the cosmetics, pharmaceutical and food industries. Their task is primarily to prolong the shelf life of selected products – cosmetics, medicines or food – by maintaining their microbiological purity. Parabens protect products against deterioration and microorganisms, extending their durability by up to several months without interfering with their composition and operation. Parabens do not change the aroma, taste, density or other characteristics of cosmetic or food products. However parabens, which occur in most cosmetics with a creamy or liquid formula (face creams, body lotions, foundation, tonics, lipsticks, deodorants, perfumes), are becoming increasingly worse because of the prolonged list of side effects that they may cause. The presence of intact paraben esters in human body tissues has now been confirmed by independent measurements in human urine, and the ability of parabens to penetrate human skin intact without breakdown by esterases and to be absorbed systemically has been demonstrated through not only in vitro studies but also in vivo investigation using healthy human subjects.

Abstract

Testing microbial quality of the harvested rainwater remains a challenge in many countries. The H2S test kit is a low-cost microbiological field-based test which can be used in areas where water testing facilities are limited. This study compares its efficiency with the standard indicators microorganisms in the detection of faecal contamination of rainwater in South Africa. A total of 88 rainwater samples were collected from various tanks in the Eastern Cape, South Africa over three months in 2016. The collected samples were analysed for faecal bacterial contamination using the H2S test kit, Colilert-18/Quanti-tray®/2000 and the membrane filtration technique for faecal coliforms (MFT). The correspondence rate of the H2S test kit with MFT was 88 %, while for the Colilert® it was 76 %. The H2S test kit confirmed faecal contamination when concentrations of standards indicators microorganisms were 5 most-probable number of cells/100 cm3 or higher. Overall, the best correspondence of the H2S test kit with Colilert® was observed at E. coli concentrations above 50 most-probable number of cells/100 cm3. Results of the H2S test kit correlated better with MTF, while the medium used has strongly influenced the enumeration of faecal contamination. Results point to strong effect of media used and revealed the need to calibrate the correspondence between the standard indicator microorganisms and the H2S test kit under local conditions for specific settings.

Abstract

Morpholine is an interesting moiety that used widely in several organic syntheses. The intermolecular charge-transfer (CT) complexity associated between morpholine (Morp) donor with (monoiodobromide “IBr”, 2,3-dichloro-5,6-dicyano-1,4-benzoquinone “DDQ”, 2,6-dichloroquinone-4-chloroimide “DCQ” and 2,6-dibromoquinone-4-chloroimide “DBQ”) π–acceptors have been spectrophotometrically investigated in CHCl3 and/or MeOH solvents. The structures of the intermolecular charge-transfer (CT) were elucidated by spectroscopic methods like, infrared spectroscopy. Also, different analyses techniques such as UV-Vis and elemental analyses were performed to characterize the four morpholine [(Morp)(IBr)], [(Morp)(DDQ)], [(Morp)(DCQ)] and [(Morp)(DBQ)] CT-complexes which reveals that the stoichiometry of the reactions is 1:1. The modified Benesi-Hildebrand equation was utilized to determine the physical spectroscopic parameters such as association constant (K) and the molar extinction coefficient (ε).