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The Effect of the Malt Grinding Degree on the pH Value and Extract Content in Beer Mash

Abstract

In recent years, a dynamic development of brewing has been observed. Increasingly, production of malt and beer takes place even in smaller industrial factories, breweries restaurants or at home. Extraction is a process applied in a variety of industries, including food production, as a way of extracting specific ingredients from their mixtures. As a result of this process, not only sugars, proteins, fats, enzymes, vitamins, colorants, fragrances and flavors, but also malt and hop extracts are being isolated. In the process of mashing, in which the malt ingredients are being extracted, many biochemical, physical and chemical changes take place. The aim of the study was to analyze the effect of the degree of fragmentation of pilsner type malt on the amount of extract obtained and the pH of the mash. It has been observed that the degree of malt fragmentation has a significant effect on the content of the extract in the mash: the more fragmented malt, the more malt extract in mash produced using the malt. It has also been found that the pH of the mash increases with the average particle size of malt.

Open access
Electricity Storage in Energy Clusters

Abstract

The article aims to present the results of analysis and evaluation of using energy clusters as a bulk electricity storage. There were developed an analytical model of a sample microgrid (on-grid) and analysed using a software dedicated for optimizing such microgrids. The model of microgrid consist on electricity commercial and residential loads, photovoltaic and wind installations and batteries.

Open access
Evaluation of Flat Fan Nozzles Operating Parameters Under Conditions of Accelerated Boundary and Destructive Wear

Abstract

Two tests were carried out to measure the standard flat fan nozzles wear during a specific period of an accelerated wear procedure. The first test aimed at getting 10% increase in the flow rate compared to the nominal flow rate, which is the threshold to replace the nozzles according to the nozzles testing standards. The second test was to wear the nozzles intensively (100 hours of accelerated wear), which represents the use of nozzles beyond the allowed threshold. The results showed that the flow rate reached 1.31 l·min−1 (equal to 10% increase) for the tested nozzles after 35 hours of the wear test. For the second test, the 10% increase of the flow rate was reached after approximately 30 hours. The wear rate reached 27.5% at the end of the test and this is 2.7 times more than the standardized threshold.

Open access
Experimental Verification of Method to Synthesize the Track Vertical Irregularities

Abstract

The paper focuses on the experimental verification of the results derived from numerical simulations, based on a model of the bogie-track system, where the vertical track irregularities are introduced in the form of a pseudorandom function. This function comes from an original method of synthesizing the vertical track irregularities, depending on the geometric quality of the track and on the velocity. To verify the method, the root mean square (RMS) of the simulated accelerations in the axles and the bogie frame against each axle is compared to the experimental accelerations within the frequency range of wavelengths of the track vertical irregularities from 3 to 120 m. The results have shown a good correlation between the simulated RMS accelerations for a low quality track and the measured RMS accelerations.

Open access
Green Propulsion Research at TNO the Netherlands

Abstract

This paper describes the recent theoretical and experimental research by the Netherlands Organisation for Applied Scientific Research (TNO) into green replacements for hydrazine, hydrazine derivatives and nitrogen tetroxide, as propellants for in-space propulsion. The goal of the study was to identify propellants that are capable of outperforming the current propellants for space propulsion and are significantly less hazardous for humans and the environment. Two types of propellants were investigated, being monopropellants and bipropellants. The first section of the paper discusses the propellant selection. Nitromethane was found to be the most promising monopropellant. As bipropellant, a combination of hydrogen peroxide (HP) and ethanol was selected, where the ethanol is rendered hypergolic with hydrogen peroxide. The second part of the paper describes the experimental verification of these propellants by means of engine testing. Initiation of the decomposition of nitromethane was found to be problematic, hypergolic ignition of the hydrogen peroxide and ethanol bipropellant however was successfully demonstrated.

Open access
Heat Transfer Determined by the Temperature Sensitive Paint Method

Abstract

The paper presents practical aspects of determining the amount of heat flow by measuring the distribution of surface temperature using the Temperature Sensitive Paint (TSP) method. The quantity measured directly with TSP is the intensity of the excited radiation, which is then converted to surface temperature. The article briefly presents three different methods for determining the heat transfer coefficient. Each of these methods is based on a separate set of assumptions and significantly influences the construction of the measuring station. The advantages of each of the presented methods are their individual properties, allowing to improve accuracy, reduce the cost of testing or the possibility of using them in tests of highly complex objects. For each method a mathematical model used to calculate the heat transfer coefficient is presented. For the steady state heat transfer test method that uses a heater of constant and known thermal power, examples of the results of our own research are presented, together with a comparison of the results with available data and a discussion of the accuracy of the results obtained.

Open access
How can people be convinced to buy electric cars? – case of Slovenia

Abstract

Electric cars represent a promising energy-and carbon-efficient alternative to internal combustion engine cars. However, as mobility behaviour is highly habitual, convincing people to switch from conventional cars to electric is challenging. In the following research, which was carried out in the past years in Slovenia, an attempt was made to determine what influences people’s buying habits and what would motivate them to buy an electric car. It appeared that the most relevant factor for not purchasing electric cars is, firstly, its overall too high price, and, secondly, short driving ranges. Different studies, as well as the results of the following research have revealed that there is no single measure which would dramatically increase the demand for electric cars. The solution is to combine different measures or strategies like Top – Down and Bottom – Up, where both the government and car industry should come across.

Open access
Increasingly Safe, High-Energy Propulsion System for Nano-Satellites

Summary

Numerous attempts have been undertaken to develop propulsion systems for nano-satellite-type spacecrafts to enable their maneuvering in orbits. One of the potentially viable chemical propellant propulsion systems is a hybrid system. The present paper studies propellant composition variants with the metal hydride as fuel that can be chosen for a nano-satellite hybrid propulsion system. It defines key requirements for chemical propellant nano-satellite propulsion systems, and specifies potential propellant pairs based on a compact metal hydride. The study describes basic technical characteristics of a 1U CubeSat propulsion system.

Open access
Innovative Calculation Method of the Productivity of Vibrating Screens Used in Mineral Aggregates Sorting

Abstract

In the process of preparing cement or asphalt concrete – frequently used in ways, roads and access road construction, it is necessary to sort out poly-dispersed granular mixtures from bilge deposits or quarries. The mechanical sieving performs the separation of the granules on dimensional sorts (the size of graded grains can be 1... 70 mm) by means of machines called screeners. In the case of vibrating screeners, the working body (the sieve) presents a vibratory movement that ensures a high productivity of the screening machine and a very good quality of the final products obtained. The article studies the productivity of the vibrating screen used in mineral aggregates sorting process obtained by different methods. In this regard, a pragmatic simplified formula called Pragma is proposed, a formula which was tested with good results in situ experiments done on a bi-mass vibrating screen in a pilot station.

Open access
Keeping Higher Education Aligned with the Requirements and Expectations of the Knowledge-Based Economy

Abstract

Paper describes the procedure for developing academic programs which are properly aligned to the requirements of the knowledge-based economy. The paper also addresses the continuous quality improvement (CQI) process with the CQI loop closing on the program level and the course level. This process is needed to make continuous adjustments to an academic program, so that the program is always aligned to the constantly-changing needs of the economy. Paper also discusses the system of mutual dependency between the academic program and external partnership like local industry, secondary schools, local government, local community, regional business incubator center, other educational institutions, alumni and industrial advisory council. The ongoing collaboration with external partners allows the program to prosper and grow.

Open access