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  • Author: Peter Šugár x
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Micromachining of Austenitic Steel by Pulsed Nd:Yag Laser

Abstract

Laser micromachining presents a possibility to create new structures on the surface of any type of materials, typically with micron-range dimensions. Interaction mechanisms of laser micromachining is a complex process and it strongly depends both on laser input parameters and material properties. This article shows partial results of experimental research, focused on investigation of laser micromachining process of X5CrNi18-10 austenitic steel by pulsed Nd:YAG laser. The main goal was to evaluate laser micromachining process from the viewpoint of input parameters modification and reached surface quality

Open access
Analysing the Properties of Surface Layers Generated by Sheet Metal Forming Operations

Analysing the Properties of Surface Layers Generated by Sheet Metal Forming Operations

The paper brings results of the surface layers properties analysis of a thin wall hollow sheet metal parts, produced by metal spinning and deep drawing. The influence of mandrel (workpiece) frequency of rotation on the spun parts surface layer strainhardening is studied and compared with the quality of the formed part surface layer produced by deep drawing technology.

Open access
Technology-Based Sheet Metal Classification and Coding System

Technology-Based Sheet Metal Classification and Coding System

Group technology (GT) concept uses design similarity measure to identify the most similar design and retrieve a useful process plan. One of the existing formal methods of machine parts classifying for the group technology applications is the coding and classification. The researchers have developed many different GT coding schemes, which very precisely describe the design characteristics of the parts, but many of them do not explicitly describe the process plan. The paper presents a new approach to the sheet metal part coding and classification with plan-based attributes implementation in accordance with the technical standard STN 226001.

Open access
CONCRETE CANOE: A COMPLEX CONCRETE TECHNOLOGY

Abstract

The Concrete Canoe Competition has been organized second time in Hungary in 2013. The main point of the competition is to design and create a floating concrete object with specified dimensions, which does not contain statically rigid frame. A speed-trial is also part of the contest. The team of Szent István University, Ybl Miklós Faculty of Architecture and Civil Engineering attended both the first (2012) and the second (2013) competition. In both years the main part of designing and creation of the canoe was under the direction of employees of Building Materials division of the Insitute. Building a concrete canoe proved to be a complex challenge. Knowledge of different engineering fields was required to solve the task - questions about material properties, hydrodynamics, statics, technologies were needed to be solved.

Present paper introduces the authors’ experience, investigations, and means of realization of the concrete canoe.

Open access
Effect of nitrogen fertilization and genotype on the yield and yield components of winter wheat
Einfluss von Stickstoffdüngung und Sorte auf den Ertrag und die Ertragskomponenten von Winterweizen

Summary

The effect of N fertilization on the yield, yield components, harvest index (HI), and chlorophyll content (SPAD (soil plant analysis development) index) of winter wheat cultivars was investigated in a long-term experiment in Hungary between 2006/2007 and 2008/2009. Maximal grain yield was reached at 80 and 160 kg · ha–1 N treatments, the higher N rate did not lead to a further yield increase in any of the years. A substantial year effect was observed for the yield and yield components. A negative correlation was found between grain number and thousand-kernel weight (TKW). Mv Verbunkos gave among the varieties the highest grain yield, grain number per spike, and SPAD value. There was a significant (P<0.001) positive correlation between the yield and the number of grains per square meter (r=0.85) and between the yield and the SPAD index (r=0.59). A significant (P<0.01) negative correlation was detected between the yield and the TKW (r=–0.44) and a positive correlation between the yield and the HI (r=0.51). Regression analysis revealed a significant linear relationship between the yield and the yield components (number of grains per square meter and TKW) at the various N levels.

Open access
Growth analysis of winter wheat cultivars as affected by nitrogen fertilization / Wachstumsanalyse von Winterweizensorten in Abhängigkeit von Stickstoffdüngung

Summary

Growth analysis helps explain the differences in yield and growth potential between cultivars in response to management practices and environmental conditions. The aim of the research was: (i) to investigate the effect of nitrogen fertilization on the growth and growth parameters of different wheat (Triticum aestivum L.) cultivars and (ii) to study the relationship between yield and growth parameters at the individual plant and plant stand level. In the two-factorial, split-plot experiment, the main plot was the nitrogen (N) treatment and the sub-plot was the cultivar. In response to N fertilization, the values of growth rate parameters increased up to the N160 treatment. The mean values of crop growth rate (g m-2 day-1) in the treatments were as follows: N0: 10.4, N80: 15.4, N160: 17.2 and N240: 16.3. The leaf area index, leaf area duration and especially the duration of the flag-leaf gave a good reflection of the effect of N fertilization. Multiple regression analysis demonstrated the significant effect of growth rates, size and duration of leaf area, biomass distribution and yield components on the yield. The results showed that understanding the growth of plants is important for optimizing management decisions.

Open access
Friction Evaluation of Laser Textured Tool Steel Surfaces

Abstract

Surface textures can be defined as a regularly arranged micro-depressions or grooves with defined shape and dimensions. These textures, if they are manufactured by laser ablation process, contribute to a significant improvement of the tribological, optical or various biological properties. The aim of this paper is to analyze the influence of the surface textures prepared by laser surface texturing (LST) at the friction coefficient value measured on the tool (90MnCrV8 steel) – workpiece (S235JRG1 steel) interface. Planar frontal surfaces of compression platens have been covered by parabolic dimple-like depressions with different dimensions. The morphological analysis of such manufactured depressions has been performed by laser scanning microscopy. Influence of such created textures on the tribological properties of the contact pair has been analyzed by the ring compression test method in the terms of hydrodynamic lubrication regime. The experimental research shown that by applying of surface textures with defined shape and dimensions and using an appropriate liquid lubricant at the same time, the coefficient of contact friction can be reduced nearly to the half of its original value.

Open access
Bionics in architecture

Abstract

The adaptation of the forms and phenomena of nature is not a recent concept. Observation of natural mechanisms has been a primary source of innovation since prehistoric ages, which can be perceived through the history of architecture. Currently, this idea is coming to the front again through sustainable architecture and adaptive design. Investigating natural innovations and the clear-outness of evolution during the 20th century led to the creation of a separate scientific discipline, Bionics. Architecture and Bionics are strongly related to each other, since the act of building is as old as the human civilization - moreover its first formal and structural source was obviously the surrounding environment. Present paper discusses the definition of Bionics and its connection with the architecture.

Open access