Polyamide surface layer nano-indentation and thermal properties modified by irradiation

This study describes the effect of electron radiation on the nano-mechanical properties of surface layers of selected polyamide (PA) types. Electron radiation initiates the cross-linking of macromolecules in the polyamide structure, leading to the creation of a 3Dnetworkwhich fundamentally changes the properties of the tested polymers. Selected types of polyamide (PA 6, PA 66 and PA 9T) were exposed to various intensities of electron radiation (33 kGy, 66 kGy, 99 kGy, 132 kGy, 165 kGy and 198 kGy). The cross-linked polyamides' surface properties were measured by means of the modern nano-indentation technique (Depth Sensing Indentation; DSI), which operates on the principle of the immediate detection of indenter penetration depth in dependence on the applied load. The evaluation was preformed using the Oliver-Pharrmethod. The effect of electron radiation on the tested polyamides manifested itself in the creation of a 3D network, which led to an increase of surface layer properties, such as indentation hardness, elastic modulus, creep and temperature resistance, by up to 93%. The increase of temperature and mechanical properties substantially broadens the field of application of these materials in technical practice, especially when higher temperature resistance is required. The positive changes to the nano-mechanical properties as well as mechanical and temperature capabilities instigated by the cross-linking process were confirmed by the gel volume test. These measurements lay the foundation for a detailed study of this topic, as well as for a more effective means of modifying chosen properties of technical polyamide products by radiation. © 2020 by the authors.European Regional Development FundEuropean Union (EU) [CZ.1.05/2.1.00/19.0376]; Czech Ministry of Education, Youth and Sports of the Czech Republic within the National Sustainability Program [LO1303 (MSMT-7778/2014)]; TBU in Zlin Internal Grant Agency [IGA/FT/2020/003

Abrasive surface finishing on SLM 316L parts fabricated with recycled powder

Improving the surface roughness quality of 3D printed components, especially metallic ones, which are fabricated from the selective laser melting (SLM) method, has drawn enormous attention from the research community. It should be noted that various studies on this topic have reported that precise surface roughness results can be obtained with various techniques that are indeed not cost-effective. Differing itself from these studies, this manuscript investigates an economical solution for fabricating and surface treating SLM components. Specifically, the inspected specimens were printed with recycled 316L stainless steel powder and treated solely with two abrasive surface finishing methods. In the manuscript, two scanning strategies namely meander and stripes, and three types of surfaces were investigated. Subsequently, their 2D and 3D surface roughness results were elaborated. After the proposed herein abrasive treatment, 3D surface roughness arithmetical mean height of a surface (Sa) value of 0.9 mu m can be achieved.Web of Science116art. no. 286

On possible parent crater for Australasian tektites: Geochemical, isotopic, geographic and ballistic constraints

A set of Australasian tektites (AAT) has been geochemically characterized by methods of activation analysis. Based on the acquired data as well as previously published geochemical, mineralogical, petrographical and isotopic data on both AAT and their potential source materials, and considering geographic and ballistic constraints known from other tektites and their strewn fields, probable source materials and location of the parent impact crater for AAT have been discussed

WESNA - program for creation html presentations with php components

The goal of my work is creating graphics user environment for design web presentation with options for inserting php components. The final product will contain administration for control of single component through the web interface

Determination of lanthanides in agricultural crops by instrumental and radiochemical neutron activation analysis

The lanthanide elements were measured in soils and agricultural crops collected in an area polluted by emissions from a phosphate fertilizer plant. Concentrations of lanthanides in the soil and crop samples were determined by instrumental neutron activation analysis (INAA). Selected crop samples were also analyzed using radiochemical neutron activation analysis (RNAA) based on alkaline-oxidative fusion of the irradiated samples followed by precipitation of REE oxalates. Elevated levels of lanthanides were found in some samples, especially in wheat chaff and parsley

Business process analysis of RWE CZ

Práce se zabývá analýzou podnikových procesů a procesního řízení v plynárenské společnosti RWE CZ. Konkrétní analýza pak probíhá v již vytvořeném jednotném procesním modelu RWE CZ tzv. Master Modelu. Kromě analýzy struktury Master Modelu a důvodů jeho zavedení, je prakticky analyzována skupina procesů Nákup. Jednotlivé druhy modelů v rámci Master Modelu jsou tak vysvětleny na konkrétním příkladě a na závěr jsou navrženy kroky pro zlepšení. V úvodu je věnována kapitola s obecnými definicemi podnikového procesu a podnikového informačního systému a jejich vzájemnými vztahy. Dále jsou pak definovány obecné požadavky na informační systémy v energetice a je provedena stručná analýza nabídky ERP produktů, v tomto odvětví. Teoretické poznatky nabyté v úvodní a v následující kapitole jsou prakticky poukázány na příkladu RWE CZ. Celá práce je potom zaměřená primárně na ekonomické systémy používané v energetice a důraz je kladen na efekty plynoucí z nasazení těchto systémů, jak informatické tak ekonomické. Závěr práce je věnován především harmonizaci informačních systémů v rámci skupiny RWE v ČR, zvláště pak nasazení systému SAP IS-U

WESNA - program for creation html presentations with php components

The goal of my work is creating graphics user environment for design web presentation with options for inserting php components. The fi nal product will contain administration for control of single component through the web interface

Methods for IT investment evaluation and decision making

The aim of the final thesis Methods for IT investment evaluation and decision making is to verify relationship between strategy of the company its Enterprise Architecture and IT investments evaluation. To achieve the aim of the thesis is necessary to define the term of Enterprise Architecture and its relationship with IT Project Portfolio Management. The literature retrieval which follows after is focused on calculation of IT investment profitability and return. The calculation is very difficult due to intangible benefits which are one of the common goals of IT investments. The customer satisfaction, improve of the current business process or employees satisfaction are one of the examples of the intangible benefits. Cost/Benefit analysis is one of the methods depicted for calculation of the intangible benefits. Methods for decision support as Analytic Hierarchy Process are highlighted as the significant instrument. The risk analysis and simulation of the risk in IT investments decision making are also mentioned but according to the scope of thesis just very briefly. Major methods are used on the model example of the evaluation and decision making process to demonstrate the whole theoretical part of the thesis. The biggest added value of the final thesis is the deep analysis of the relationship between strategy of the company its Enterprise Architecture and IT investment evaluation. Entire final thesis should be used as the fundament for IT investment evaluation and decision making framework

WESNA - program for creation html presentations with php components

The goal of my work is creating graphics user environment for design web presentation with options for inserting php components. The fi nal product will contain administration for control of single component through the web interface

WESNA - program for creation html presentations with php components

The goal of my work is creating graphics user environment for design web presentation with options for inserting php components. The final product will contain administration for control of single component through the web interface