Istraživanje utjecaja pripreme površine osnovnog materijala na svojstva toplinski naštrcanog sloja

Using specimens, a research was conducted to determine the influence of the base material surface preparation for 42CrMo4 on the final coating, prior to actual thermal spraying. During thermal spraying, an Al-Ni-alloy was used as an interlayer before the actual coating with Cr-Mo-Ni. The surface hardness and the hardness distribution across the thickness of the sprayed coating were measured and the structure of respective sprayed coatings was photographed. A comparison of experimental results enabled the identification of the particular material preparation method with an optimal ratio of the satisfactory coating thickness and its hardness.Na uzorcima je istraživan utjecaj kvalitete pripreme površine osnovnog materijala 42CrMo4 prije naštrcavanja na svojstva toplinski plinski naštrcanog sloja. Pri naštrcavanju je kao međusloj korištena legura Al-Ni, dok je za završni sloj korištena legura Cr-Mo-Ni. Izvršena su ispitivanja površinske tvrdoće, toka tvrdoće po debljini naštrcanog sloja, te odgovarajuća snimanja struktura naštrcanih slojeva. Usporedbom rezultata ispitivanja utvrđena je priprema površine osnovnog materijala kod koje se postiže prihvatljiva debljina naštrcanog sloja uz postizanje zadovoljavajućih tvrdoća u naštrcanom sloju

Istraživanje utjecaja pripreme površine osnovnog materijala na svojstva toplinski naštrcanog sloja

Using specimens, a research was conducted to determine the influence of the base material surface preparation for 42CrMo4 on the final coating, prior to actual thermal spraying. During thermal spraying, an Al-Ni-alloy was used as an interlayer before the actual coating with Cr-Mo-Ni. The surface hardness and the hardness distribution across the thickness of the sprayed coating were measured and the structure of respective sprayed coatings was photographed. A comparison of experimental results enabled the identification of the particular material preparation method with an optimal ratio of the satisfactory coating thickness and its hardness.Na uzorcima je istraživan utjecaj kvalitete pripreme površine osnovnog materijala 42CrMo4 prije naštrcavanja na svojstva toplinski plinski naštrcanog sloja. Pri naštrcavanju je kao međusloj korištena legura Al-Ni, dok je za završni sloj korištena legura Cr-Mo-Ni. Izvršena su ispitivanja površinske tvrdoće, toka tvrdoće po debljini naštrcanog sloja, te odgovarajuća snimanja struktura naštrcanih slojeva. Usporedbom rezultata ispitivanja utvrđena je priprema površine osnovnog materijala kod koje se postiže prihvatljiva debljina naštrcanog sloja uz postizanje zadovoljavajućih tvrdoća u naštrcanom sloju

Fatigue crack growth and fracture mechanics analysis of a working roll surface layer material

Fatigue crack growth and fracture mechanics analysis of a working roll surface layer material is presented in this paper. The research is done on a hot strip mill working roll where High Chromium Steel is used for roll’s shell material. To obtain corresponding parameters, a rectangular single edge notched bend specimens – SENB, according to standard BS 7448, were used. The fatigue crack growth analysis was done on a resonant testing machine with use of special crack gauges, while for fracture mechanics parameters the electro–mechanical testing machine was used

Analysis of the vehicle exhaust system corrosion and its effect on the ECO-test result

This paper deals with analysis of the vehicle exhaust system quality and its influence on the results of measuring exhaust emissions of the Otto and Diesel motor vehicles. Results of eco-tests obtained from correct and faulty vehicle exhaust systems were compared to conclude that damages caused by corrosion had significant influence on the pass rate of vehicles at eco-test. Referring to vehicles with the Otto engine, damages in the exhaust system increase the oxygen level, which results in the increased λ factor and in failure at the eco-test. On the contrary, vehicles with the damaged Diesel engine exhaust system allow the gas to leak through the damage, so the measurement of blackening is lower, i.e. the eco-test result is better than that of the exhaust system without damage

Utjecaj poprečne brzine na nepravilnosti površine dobivene abrazivnim rezanjem vodenim mlazom

The paper deals with the calculation of the optimal traverse speed for diff erent types of materials, which is very important for predication, imaginings and dimensioning of technological factors and selection of the materials with the aim to increase of surface quality at abrasive waterjet cutting (AWJ) technology. The surface irregularities of the experimental used materials AISI 304, AISI 309 have been measured by non-contact shadow method. New empirically compiled equations of the infl uence of the traverse speed on tensometrical state of cut, deformation resistance of material and surface roughness Ra are at AWJ cutting available.Rad se bavi proračunom optimalne brzine rezanja za različite vrste materijala, što je vrlo važno za predikaciju, osmišljanje i dimenzioniranje tehnoloških čimbenika i izbor materijala s ciljem da se poveća kvaliteta površine reza tehnologijom abrazivnim vodenim mlazom (AWJ). Površinske nepravilnosti eksperimentalno korištenih materijala AISI 304, AISI 309 su mjerene bezkontaktnom metodom sjene. Dobivena je nova empirijska jednadžbe utjecaja brzine na tenzometrijsko stanje rezne površine, deformacijsku otpornost materijala i površinsku hrapavost Ra kod AWJ rezanja

Fatigue crack growth and fracture mechanics analysis of a working roll surface layer material

Fatigue crack growth and fracture mechanics analysis of a working roll surface layer material is presented in this paper. The research is done on a hot strip mill working roll where High Chromium Steel is used for roll’s shell material. To obtain corresponding parameters, a rectangular single edge notched bend specimens – SENB, according to standard BS 7448, were used. The fatigue crack growth analysis was done on a resonant testing machine with use of special crack gauges, while for fracture mechanics parameters the electro–mechanical testing machine was used

Application of a New Potentiometric Sensor for Determination of Anionic Surfactants in Wastewater

A new screen-printed potentiometric microsensor (SPMS) for the determination of anionic surfactants (ASs) based on the dimethyldioctadecylammonium-tetraphenylborate (DDA-TPB) ion pair as a sensing material was applied to real industrial effluents. The sensor is accurate, inexpensive, simple and very sensitive. The solutions of cetylpyridinium chloride (CPC) of the concentrations down to 5· 10–5 mol dm–3 were used as a titrant. Standard addition method was used for checking the precision and accuracy of measurements providing satisfactory results with recoveries between 98.3 to 102.0 % in pure AS solutions and 99.0 to 114.5 % in wastewater. Standard spectrophotometric method Methylene Blue Active Substances (MBAS) was used as control for comparison of the results obtained with the new sensor. The results obtained using SPMS were compared with those obtained by the polymeric membrane ion-selective electrodes (ISEs), containing the same sensing material, and exhibited good mutual agreement

A Data-informed Public Health Policy-Makers Platform

Hearing loss is a disease exhibiting a growing trend due to the number of factors, including but not limited to the mundane exposure to the noise and ever-increasing amount of older population. In the framework of a public health policymaking process, modeling of the hearing loss disease based on data is a key factor in alleviating the issues related to the disease issuing effective public health policies. First, the paper describes the steps of the data-driven policymaking process. Afterward, a scenario along with the part of the proposed platform, responsible for supporting policymaking are presented. With the aim of demonstrating the capabilities and usability of the platform for the policy-makers, some initial results of preliminary analytics are presented in a framework of a policy-making process. Ultimately, the utility of the approach is validated throughout the results of the survey which was presented to the health system policy-makers professionals involved in the policy development process in Croatia

Klasifikacija tehničkih materijala prema klasama obradivosti kod hidroabrazivnog rezanja

This paper presents the major cutting knowledge, the opinion data and the results of actual theoretic parameters solutions and the current results, estimated by contemporary needs of hydro abrasive cutting technology. Here is a newly opened and discussed question of current data terminology disunity in the area of metrology topography surfaces of cutting walls created by abrasive waterjet.U radu su prezentirana temeljna znanja, razmišljanja i rezultati teorijskih rješenja vezano uz trenutne procijenjene suvremene potrebe za hidroabrazivnom tehnologijom rezanja. Ovdje je i ponovo otvoreno pitanje trenutne terminologije u području mjeriteljstva topografi je površina dobivenih rezanjem abrazivnim vodenim mlazom