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Bending fatigue strength coefficient the low carbon steel with impurities

Abstract

The article discusses the results of a study investigating the effect of the number of fine non-metallic inclusions (up to 2 μm in size) on the fatigue strength of structural steel during rotary bending. The study was performed on 7 heats produced in an industrial plant. Fourteen heats were produced in a 100 ton oxygen converter. All heats were subjected to vacuum circulation degassing.

Steel sections with a diameter of 18 mm were hardened and tempered at a temperature of 200, 300, 400, 500 and 600°C. The experimental variants were compared in view of the applied melting technology and heat treatment options. The heat treatments were selected to produce heats with different microstructure of steel, from hard microstructure of tempered martensite, through sorbitol to the ductile microstructure of spheroidite. The results were presented graphically, and the fatigue strength of steel with a varied share of non-metallic inclusions was determined during rotary bending. The results revealed that fatigue strength is determined by the relative volume of fine non-metallic inclusions and tempering temperature.

Open access
Context of production engineering in management model of Value Stream Flow according to manufacturing industry

Abstract

The popularity of visual management in the lean concept is caused by the possibility to apply it in solving different kind of issues related to reduce waste or process planning. The adaptations of VSM is focused on stream flow, identifying waiting and productive times in accordance to material and information flow. In this paper five basic areas of value stream flow management have been presented and characterized. Discussion under the 5 areas on the VSM process included identifying the dominant stream in the area and the range of factors affecting the flow of the stream. Based on an observation of processes in the manufacturing industry and a literature review, the graphic model of mutual cooperation between value stream areas (1-5) has been presented.

Open access
Effect of Sonication on The Mechanical Properties of Organic Mixed Grain Bread

Abstract

The aim of this study was to determine the effect of ultrasound waves on mechanical properties of organic bread. Mixed grain bread baked at a local bakery according to its original recipe was the material subjected to testing. Prior to baking, the dough was sonicated at frequencies of 20 kHz and 40 kHz for 3 minutes, and at a frequency of 100 kHz for 3 minutes and 6 minutes. The mechanical properties of the bread (compression test, penetration test and TPA) were examined after 24 h, 48 h and 72 h following the baking process. The maximum work obtained in the compression test after 24 h following the baking ranged from 616 N to 668 N. On the next day following the baking, the maximum work value ranged from 750 N to 898 N, while after 72 hours, it ranged from 988 N to 1135 N. In the penetration test, the following results were obtained: after 24 hours, the force value ranged from 2.71 N to 3.17 N; after 48 hours following the baking, it ranged from 4.90 N to 6.35 N; and after 72 hours following the baking, from 3.98 N to 6.88 N. As regards elasticity, the obtained results fell within the following ranges: after 24 hours following the baking, from 0.53 to 0.58; after 48 hours following the baking, from 0.43 to 0.55; and after 72 hours following the baking, from 0.40 to 0.45. Gumminess measured after 24 hours following the baking ranged from 8.75 N to 18.71 N; after 48 hours, from 10.83 N to 15.48 N; and after 72 hours, the gumminess values ranged from 15.57 N to 19.06 N. As regards chewiness, the following results were obtained: after 24 hours following the baking, from 8.00 N to 17.59 N; after 48 hours following the baking, from 9.77 N to 13.87 N; and after 72 hours following the baking, from 12.56 N to 16.85 N. The frequencies and durations of sonication applied changed no mechanical properties of the tested bread.

Open access
Effect of the Fertilizer Application Method on Soil Abundance in Available Sulfur

Abstract

Efficient increase in the content of available forms of elements in soil depends not only on their total content introduced to soil material, but also on the technology of its application. Technology consists of techniques and date of application as well as agronomic practices aimed at maintaining proper conditions for element transformations. The method of application of waste elemental sulfur and ground phosphate rock was assessed. Doses of 20 and 40 mg S as well as 40 and 80 mg P·kg−1d.m. were added to medium soil; 30 and 60 mg S as well as 60 and 120 mg P·kg−1d.m. were added to heavy soil. The soil samples were collected on the day of application of materials and after 15, 30, 60 and 90 days. The soil pH value decreased during the incubation. An increase in available sulfur content was observed in both soils after elemental sulfur application; the sulfur content in the medium soil depended on the dose of waste. The soils with the addition of a double dose of ground phosphate rock had the highest content of available phosphorus.

Open access
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
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
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
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