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Abstract

The research was carried out at the Department of Hydraulic Engineering, Faculty of Civil Engineering, Slovak University of Technology in Bratislava with close cooperation with Institute of Water Structures, Faculty of Civil Engineering, Brno University of Technology. One of the important goals was the determination of the most accurate approach related to the computational fluid dynamics modeling of the air-water interaction. Research consists of two main research methods to ensure the accuracy, set up the possibilities of cooperation and the results control. The first method was the physical model of broad-crested weir installed in collapsible canal in hydraulic laboratory and the second was numerical computational fluid dynamics model of broad-crested weir created in same scale. In free surface flows the air entrainment phenomena plays an important role. Air entrainment is affecting the volume fraction, velocity field, energy dissipation and many other parameters related to dynamic behavior of water near the crests. Different approaches were carried out to identify most accurate computational fluid dynamics setup compared to physical model measurements. Compared results and the accuracy assessment are summarized and the best computational fluid dynamics parameterization is recommended.

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Analysis of construction cost prediction studies – global perspective

It is well known that the civil engineering constructions are subjected to cost risk and time overruns. The uncertainties of the cost of construction many times result in disputes among stakeholders. The recent cost fluctuation in sand price in Tamil Nadu is a good example of time and cost overruns. There are too many models developed to predict the cost of construction by using different parameters and tools. The objectives of this research are to analyse the importance of research in this field, the countries focusing on this issue, level of implementation by the practicing engineers, the tools often or successfully used, the difficulties in predicting the cost and the accuracy of prediction and bringing out a useful conclusion to provide the direction for future research. In this research, a sample of 324 research papers out of more than 2000 papers listed in Scopus database between the years 1990 and 2015 were considered and analyzed on five factors. The five factors are 1) authors affiliation – academics, industry or both; 2) country; 3) tools used – ANN, regression, time-series models, etc.; 4) complexity involved or ease of use; 5) accuracy of results. The results show interesting information.

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In this study, the peach kernel proteins were extracted and treated with alkaline proteinase to generate peach kernel protein hydrolysate (PKH), which showed angiotensin converting enzyme (ACE) inhibition activity. The hydrolysate was separated into four fractions and their anti-ACE activities were investigated. Our results showed that all PKHs had anti-ACE activity, and the lowest molecular weight fraction PKH4 had the highest ACE inhibitory activity. Lineweaver–Burk plots illustrated that the inhibition types of PKH3 and PKH4 were non-competitive. The Ki of PKH4 was lower than Ki of PKH3; suggesting PKH4 had high affinity to ACE. Amino acid composition analysis showed that the best anti-ACE peptide PKH4 possessed high levels of hydrophobic amino acids, branched-chain amino acids, and aromatic amino acids. In summary, our findings demonstrated that high anti-ACE activity is negatively related to the size of the PKHs and possibly the composition of amino acids, and the PKH4 was the best ACE inhibitor. Further, peach kernel peptides can be developed as a functional food for patients with hypertension.

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Abstract

Diagnostics is an important and challenging task of the structural analysis and condition assessment of historic masonry structures. However the interpretation of the results of the measurements, especially for buildings made from brick and stone, is to be more subjective than that for concrete structures. Therefore improvement of the reliability of the used techniques and finding better correlations between the test results and the mechanical properties of masonry has proven to be of great importance.

While several diagnostic procedures are commonly used in practice to test mechanical properties of masonry, e.g. Schmidt hammer test, analysis of drilled samples, penetration tests, etc. the results of these methods are considered reliable under laboratory conditions, several additional factors have to be taken into account in case of an in-situ application of these methods, that may largely affect the obtained results and conclusions. The results of the diagnostic procedures therefore need to be interpreted with a view to these environmental factors.

The paper focuses on the practical use of several test methods for historic masonries via a real case study. The presented case study attempts to demonstrate benefits from the combined application of Pendulum Schmidt Hammer, moisture meter and scanning electron microscopy.

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Abstract

The results of terrestrial laser scanning are point clouds, which are becoming an increasingly common initial digital representation of real-world objects. Since point clouds in the most cases represent a huge amount of data, automation of the processing steps is advisable. The paper brings a short review of the most reliable methods of cylinder extraction. An innovative algorithm is proposed for an automated detection of cylinders and also for estimating their parameters from 3D point cloud data. The method was tested on the complex point clouds of pipelines. The proposed algorithm was implemented to a standalone application based on MATLAB® software.

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Lichens are a symbiotic relationship between a fungus and a photosynthetic partner. Chemical characterization and bioactive potentials (antiproliferative, antioxidant, and antibacterial) of five lichen species (Evernia prunastri, Platismatia glauca, Pseudevernia furfuracea, Ramalina fastigiata, and Ramalina farinacea) were assessed. Five lichen metabolites (usnic acid, atranorin, stictic acid, evernic acid, and fumarprotocetraric acid) were analyzed by HPLC-DAD. E. prunastri was noteworthy evernic acid source. Antiproliferative activity was evaluated using human breast adenocarcinoma (MCF-7) and human hepatocellular carcinoma (HepG2/C3A) cell lines. The strongest activity was observed for P. glauca against HepG2/C3A, while the only lichen species that induced cytotoxicity against MCF-7 cell line was P. furfuracea. The highest antioxidant activity was also obtained with P. furfuracea. E. prunastri and R. farinaceae had the highest phenolic and flavonoid contents, respectively. Antibacterial activities of the extracts were determined against ten pathogenic bacteria. The most effective antibacterial agent was methanol extract of R. fastigiata. Our findings have revealed the pharmaceutical potentials of tested lichen species.

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The antioxidant and antimicrobial activities of extracts of 12 plant species growing in Brazil were determined. Antimicrobial activity against 12 food-related bacterial species was studied using the disc-diffusion, MIC, and MBC methods. Campomanesia eugenioides extract was the most active against the tested Gram-positive bacteria, whereas Parapiptadenia rigida bark extract presented the highest activity against the evaluated Gram-negative bacteria (MIC and MBC of 0.075 and 0.62 mg ml−1, respectively, against Pseudomonas aeruginosa). Those two extracts also presented high phenolic content and high DPPH and ABTS radical scavenging ability. C. eugenioides extract presented high Fe2+ chelating capacity. The results of the present study demonstrate that, among the evaluated extracts, P. rigida bark and C. eugenioides, both Brazilian native species, presented the highest potential of application as natural antimicrobial and antioxidant agents.

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Abstract

The aim of the paper is to fulfill the parametric analysis on the heating performance of a compact automotive radiator using computational fluid dynamics. The analysis has been carried out at different air velocities with different fins modeling as real fins and as porous media. SC-Tetra computational fluid dynamics software was used for this study. The fluids are incompressible; the flow was three-dimensional and turbulent. The geometry of the fins has a high impact to the heat transfer coefficient and the heat performance, so the shape, the size and the thickness of the fins are compared to each other. The results show that the ratio of the fin pitch, the wall thickness of the fins, the number of the fins, the flow depth and the geometry of the tube are the main factors of the heat transfer. The main goal is to find a dependable Nu-number correlation for this type of heat exchanger. Furthermore with the usage of this function the goal is to find the optimal shape of the radiator, which can decrease the temperature of the cooling liquid to the necessary value and has the smallest weight.

Open access

Honey is produced by honeybees from nectar, sap of plant parts, or the juicy material secreted by sucking insects living on trees. It is rich in nutritionally useful components, the occurrence of which highly depends on the botanical and geographical origin of honey. Our goal is to develop a new, rapid, and accurate combination of analytical methods for identification of botanical and geographical origin.

Physicochemical parameters (pH, electrical conductivity, moisture, and ash content), colour (L*a*b*), and antioxidant properties were determined in addition to correlative techniques, such as electronic tongue and near infrared spectroscopy. For the statistical evaluation ANOVA, principal component analysis, and linear discriminant analysis were applied.

Results showed significant differences (P<0.05) in physicochemical properties, colour, and antioxidant capacity according to the botanical origin of honeys. Electronic tongue (ET) and near infrared spectroscopy (NIR) techniques were useful in the identification of the botanical and geographical origin, showing generally good accuracy.

The physicochemical parameters are important and can serve as reference methods, completing NIR and ET as target techniques, which are promising, but need further improvement for the determination of honey origin.

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Abstract

This paper is about comparing the effectiveness of the sorbent materials of granulated activated carbon in removing of bromates from drinking water. The limit value (10 µgl−1) of bromates in the drinking water was stated by World Health Organization. In order to insure the reduced concentration of bromates in the drinking water, an experiment was performed using the batch test. In this experiment different types of sorbent materials with different properties were testing. Based on batch test were measured the parameters like the immediate adsorption capacity, the adsorption efficiency, and the concentration of bromates after the adsorption were measured at the evaluated time.

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