Developing of wear model of construction materials in abrasive soil pulp employing discriminant analysis

U radu se opisuje metoda odabira kemijskog sastava i strukture površinskog sloja konstrukcijskih materijala koji odgovaraju svojstvima abrazivne zemljane mase koja se obrađuje. Eksperiment je proveden u laboratoriju metodom "rotirajuće mase". Matematičkim modelom razvijenim za eksperiment omogućena je simulacija promjena u trošenju konstrukcijskih materijala korištenih u zemlji ovisno o promjeni kemijskog sastava i strukture konstrukcijskog materijala i vlažnosti zemlje. Rezultati pokazuju da intenzitet trošenja u šljunčanom tlu može biti prihvatljiv za materijale koji sadrže manje od 20 % C+Cr (upotrebljene u tlu s vlažnošću višom od 12 %) kao i u tribološki nepovoljnim uvjetima (vlažnost tla ispod 6 %), ako je sadržaj C+Cr u konstrukcijskom materijalu viši od 25 %.This paper presents a method of selecting the chemical composition and structure of the surface layer of construction materials to suit the property of the abrasive soil pulp being processed. The experiment was conducted in a laboratory, by the "rotating mass" method. The mathematical model developed for the experiment enables simulation of the wear changes of the construction materials used in soil, depending on changing of chemical composition and structure of the construction material and soil humidity. The results produced in the experiment have shown that the wear intensity in gravel soil may be acceptable for both materials containing less than 20 % C+Cr (used in soil with humidity of more than 12 %) and in tribological unfavourable conditions (soil humidity below 6 %), if the C+Cr content in the construction material exceeds 25 %

Material flow optimization – a case study in automotive industry

Danas je većina organizacija suočena s mnogim dilemama, bit kojih je određivanje načina postizanja ili održavanja stečenog položaja u konkurentnom okruženju. Poduzeća moraju neprestano povećavati svoju ekonomiju. Jedan od načina stjecanja nadmoći nad konkurencijom je analiza i optimizacija toka materijala, što doprinosi smanjenju troškova. Tok materijala u proizvodnoj organizaciji govori nam mnogo o organizaciji sustava. U radu se daje analiza postojećeg stanja toka materijala u jednoj proizvodnoj organizaciji motornih vozila. Predlaže se i projekt optimizacije toka materijala; projekt se sastoji od novog programa internog prijevoza i optimizacije položaja radnih štandova. U radu se opisuju postojeći problemi u internom prijevozu poduzeća i daju rješenja tih problema.Today, most contemporary organisations are facing many dilemmas, the essence of which is the determination of the ways of acquisition or maintenance of their position in the competitive environment. Companies have to continuously increase their economy. One of the ways to get competitive prevalence is analysis and optimization of material flow which contributes to the reduction of the company costs. Material flow in a production organization tells us a lot about how well the system is organised. The paper presents an analysis of the current state of material flow in a production company of the automotive branch. A project of the material flow optimization has also been proposed; the project consists of creation of a program of internal transport and optimization of the location of the working stands. The paper describes the current problems of the company internal transport and indicates solutions to those problems