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During the production of natural gas one of the major problems is the formation of hydrate crystals in the pipeline. The forming hydrate crystals can form hydrate plugs in the pipeline. The hydrate plugs lengthen production outages and result in financial losses for the producer, because the removal of the plugs is a time consuming procedure. One of the solutions used to prevent hydrate formation is the injection of modern compositions to the gas flow. The modern compositions help to dehydrate the gas, thus, the size of hydrate crystals does not increase. The substances, used in low concentrations, have to be locally injected, at the gas well sites. Inhibitor dosing depends on the amount of gas hydrate present. In the article a neural network based predictive detection solution is presented, which uses four factors.

Open access

In this study the competitiveness of Hungarian enterprises was analyzed, because relatively little research has been conducted to investigate small enterprises. More specifically, the paper examines to what extent the use of online solutions gives companies a competitive advantage. Nearly 800 companies were involved in the research, for which a new methodology was used. It is built on a multi-step model, which is based on mathematical calculations. From the result of a questionnaire survey, variables were generated to create a number of competitiveness pillars, which were used to determine the final competitiveness index of each company. The research was carried out at the Faculty of Business and Economics, University of Pécs. Scientists form the Faculty of Engineering and Information Technology, University of Pécs were involved in the online analysis of the companies, the results of which were integrated into the research findings. The analysis shows that the companies, which do not use online solutions during their operations can be competitive but generally those present in the online space are more competitive, and use more sophisticated solutions in their business processes, which has a positive effect on several functions of the company. Overall these companies have a higher competitiveness index, which confirms that it is worth using online solutions for companies.

Open access

Honey is the most important bee product. There are many secondary metabolites, carbohydrates, enzymes, and vitamins in honey, thus, honey has antimicrobial activity. In this study, in vitro antimicrobial activity of forty-two honey and eight propolis ethanolic extracts (PEE) were investigated against 16 microorganisms. Total phenolic content ranged between 20.00–124.10 mg GAE/100 g and 103–232 mg GAE/g for honey and raw propolis samples, respectively. Pine and oak honeydew honeys had higher antimicrobial activity than four different grades of Manuka Honeys up to 18 mm minimum inhibition zone diameters. The ethanolic propolis extracts showed much higher antimicrobial activity than the honey samples. Fungi species were inhibited by the propolis samples. Helicobacter pylorii (H. pylorii) was the most sensitive, whereas Streptococcus agalactiae was the most resistant bacteria among the studied microorganisms. Brazilian and Zonguldak propolis had the closest antimicrobial activity to ampicillin, streptomycin, and fluconazole. It can be concluded that both honey and propolis could be used in preservative and complementary medicine.

Open access

Modification of dairy products’ fat composition or replacement by other fats are common practices in the industry. Products in which milkfat is partially or wholly substituted by vegetable fats are defined as dairy analogues. This study delivers gap-filling information about sour cream analogues in nutritional aspects, focusing on the fat-related attributes. Analogue sour creams contained 29.6% less saturated fatty acids, 88.4% less cholesterol and 88.7% more mono- and poly-unsaturated fatty acids than the sour creams. Trans fatty acids were present in both products, which could not be linked to artificial hydrogenation in either case. Digestibility of the examined samples might be different, as sour creams had more short and medium chain fatty acids than the analogues. Overall, sour cream analogues, besides serving as an alternative to sour cream, have particular advantages based on their nutritional values.

Open access

Chemical industry has a high demand for ethylene quantity, especially with high quality. This paper discusses dynamic simulation models of an ethaneethylene high-pressure cryogenic rectification column with Unisim Design process simulator software. Distillation is one of the most essential technologies in chemical industry, it is important that the operation of the procedure can be modeled not only in steady-state mode but also in a dynamic way. The goal during this study is to make simulations with system-controlling and to investigate the effect the disturbance on the behavior of the columns.

Open access
Acta Alimentaria
Authors: D. Koren, B. Hegyesné Vecseri and G. Kun-Farkas

There are numerous scientific publications about the folate content of several types of beers available in commercial trade, but there is limited information about the effect of raw materials and technological steps of brewing on folate content. In this study the aim was to investigate different raw materials and the evolution of folate content during laboratory and pilot scale brewing. For the determination of folate content of different malts, three types of barley malts (Pilsner, Caramel, and Coloring), wheat malt, rye malt, and oat malt were analysed. For the study of the evolution of folate content during the brewing process, worts were produced on laboratory and pilot scale. Among malts, Pilsner type barley malt had the highest folate content (44.7 μg/100 g d.m.). During brewing the protein rest seemed to dissolve the majority of the folate content, and with the increasing temperature of the β- and α-amylase rests there was a further dissolution. Filtration and sparging did not have negative effect on folate concentration related to the extract content of the wort. Hop boiling had no negative effect on folate content, folate seemed to be stable during the one-hour boiling. Natural folate of barley malt seemed to be stable through the technological steps of brewing, offering the possibility to produce a foodstuff with high natural folate content.

Open access

This study aims to experimentally investigate the nucleate pool boiling heat transfer performance of magnesium oxide nanoparticles MgO based deionized water nanofluid at the atmospheric pressure condition. Dilute volumetric concentrations within a range of 0.001% to 0.01% Vol. were used to examine the pool boiling heat transfer performance represented by pool boiling curve, and pool boiling heat transfer coefficient. The heating element was a horizontal copper heated tube with a typical diameter 22 mm submerged inside the cubic boiling chamber. Efforts have been made to measure the surface temperatures along the heated tube to ensure the proper and accurate heat transfer coefficient calculations in this work. The results indicated that the pool boiling heat transfer coefficient enhancement ratio (PBHTC /PBHTC ) was intensified for volume fractions i.e. 0.001%, 0.004%, and 0.007% Vol. while it was degraded for volume concentrations i.e. 0.01%, and 0.04% Vol. compared to deionized water as baseline case.

Open access
Pollack Periodica
Authors: Ivan V. Abramov, Pavel V. Lekomtsev, Аlexander V. Romanov, Аndrey V. Buchkin, Zarina S. Saidova and Zoltan Orban

The paper presents an experimental research on anchoring devices developed for the pre-tensioning of fiber reinforced polymer tendons in the stress range between 40 and 70% of tensile strength. The technique of testing, the criteria of assessing the load capacity and the influence of preloading applied on the anchor wedges on the initial tendons slippage are described. The optimal technical configurations of the anchoring device have been obtained, including parameters regarding the necessary prior anchorage of the tendon ends based on the strength properties of the tendon bar and the requirements to avoid slippage during the tensile tests.

Open access

The propagation of an ultra-short light pulse is studied in the framework of scalar diffraction theory. Light pulses are focused by different types of wavy parabolic surfaces. The temporal-spatial behavior of the two-dimensional wave field is computed in the vicinity of the focal plane. It is shown that the slightly perturbation from the perfect parabolic shape leads a space-time dispersion of the pulse in the neighborhood of the focus.

Open access

Examining a human movement can provide a wealth of information about a patient’s medical condition. The examination process can be used to diagnose abnormal changes (lesions), ability development and monitor the rehabilitation process of people with reduced mobility. There are several approaches to monitor people, among other things with sensors and various imaging and processing devices. In this case a Kinect V2 sensor and a self-developed LabView based application was used, to examine the movement of the lower limbs. The ideal gait pattern was recorded in the RoboGait training machine and the measured data was used to identify the phases of the human gait. During the evaluation, the position of the skeleton model, the associated body joints and angles can be calculated. The pre-recorded ideal and natural gait cycle can be compared.

With the self-developed method the pre-recorded ideal and natural gait cycle can be compared and processed for further evaluation. The evaluated measurement data confirm that a reliable and mobile solution for gait analysis has been created.

Open access