A Proposal of Portfolio Choice for Infinitely Divisible Distributions of Assets Returns

In the paper we present a proposal of augmenting portfolio analysis for the infinitely divisible distributions of returns - so that the prices of assets can follow Lévy processes. In this article we propose a model in which asset prices follow multidimensional Lévy process and the interdependence between assets are described by covariance and multidimensional jump measure. Then we propose to choose the optimal portfolio based on three criteria: mean return, total variance of diffusion and a measure of jump risk. We also consider augmenting this multi-criteria choice setup for the costs of possible portfolio adjustments.portfolio analysis, Lévy processes, jump-diffusion models

Advanced forming technology

Forming is usually the final stage of metallurgical production of steel (90 % of the 1,7 billion tons of total steel production in the world) and traditionally also largely of the products made of non-ferrous metals. Many procedures and methods exist and we will focus only on some of them. The aim is usually to achieve ultra-fine grained structure, the proper microstructure and (mechanical / electrical) properties in innovative materials. The presented article mentions only some examples.Web of Science55483883

Some viewpoints of materials forming technology

Metal forming can be regarded as a process during which materials are treated by “force” and “heating” under a certain external load and boundary condition (loading mode, rate of loading, constraint condition, geometry, contact friction condition, temperature field). As well as in former times and presently from time to time detect overview lecture and articles, which have for one‘s object draw up demand on modern forming technologies one’s about new wave in the area like: shortening processes, flexibilization, integrating production processes, hollow structure technology and simulation and optimization. New metal forming technologies may be developed using new energy resources, new forming mediums and new loading methods for developing new products according to the needs of the automotive, electrical, electronic and aerospace industries. Some cases of these technologies will be presented inside of volume of this contribution.Web of Science53470870

Jon Fosse i Polen - en utakknemlig begynnelse

The article concentrates on the reception of Jon Fosse’s plays in Poland, where the dramatist remains practically unknown, although he has recently become the most frequently staged playwright in Europe. It seems that Fosses dramas have not found understanding among Polish critics. The article analyses the reviews of Fosse’s dramas published in Polish press until May 2004. Till then only three plays were staged in Polish theatres and five were translated. The author points out that Fosse’s dramas in Poland, rather than being a permanent element of the repertoire, are frequently staged as parts of various theatrical projects aiming at finding new solutions for modern drama and theatre. Finally, she concludes that the dialogue of Fosse’s plays is always their most original (although often controversial) element, regardless of the language of translation

Odabrane nove tehnologije i zadaci istraživanja u oblikovanju deformiranjem materijala

The article gives a review of selected new technologies of materials forming. That is selected 10 procedures, first, high pressure torsion processing, at the end, metal injection molding. All the new procedures have good performance and in the future for expect more the application in industry.Članak daje osvrt odabranih novih tehnologija u oblikovanju deformiranjem materijala. To je odabranih 10 postupaka, prvi, visokotlačna torziona obradba i na kraju, lijevačko injektiranje metala. Svi novi postupci imaju dobre karakteristike i u budućnosti za očekivati veću primjenu u undustriji

The Model of French Development Assistance – Who Gets the Help?

Development cooperation is an important element of international relations because it influences the power balance between major players on the world markets and in the political debate. The aim of the article was to analyze the French development assistance model based upon the amount of help sent to Africa over the period 2001-2012. The motivation of donor country is a crucial factor of development assistance, which influence not only the relations between donors and recipients, but also the effectiveness of aid. We estimated a series of dynamic panel models to assess whether the poverty-related factors play a dominant role in the distribution of help. On the contrary, we found that the most important variables appeared to be the political and economic dependencies, among others: colonial history and oil/gas reserves

Predvidanje deformacije i temperature metodom konačnih elemenata (MKE) tijekom valjanja cijevi na pilger – stanu

3D - FEM simulation was used as an efficient tool for description of stress-deformation thermal field at rolling of tubes on a pilgrim mill. The monitored objectives comprised also behaviour of working tools at this rolling. This paper assumes rolling of already pierced thick-walled blank, which passes through the pilgrim stand at simultaneous reduction of thickness of inside and outside diameters at the expense of elongation of initial length. Main attention is focused on the mentioned parameters with respect to various conditions of rolling, such as different heat transfer, different friction or different distance of insertion of the rolled product into the gauge. The input data used at simulation were derived from real conditions of tubemaking.Za prikaz termičkog polja naprezanje – deformacija tijekom valjanja cijevi na pilger - stanu učinkovito je rabljena trodimenzijska metoda konačnih elemenata (3D – MKE). U radu je razmatrano i ponašanje alata tijekom izrade cijevi valjanjem. Pretpostavljeno je valjanje šuplje debelostjene cijevnice na pilger stanu uz istovremeno smanjenje vanjskog i unutrašnjeg promjera na uštrb produljenja početne duljine. Rad se fokusira na navedene parametre obzirom na promjenjive režime valjanja poput različitog prijenosa topline, različitog trenja ili različite udaljenosti uvodenja valjanog proizvoda u uredaj. Ulazni podaci rabljeni u simulaciji odgovaraju onima iz realnog procesa valjanja cijevi

Effect of heat load on structural changes of selected corrosive resistant steels

Corrosion resistant steels are used for the prod uction of parts exposed to corrosive environment and also to thermo-mechanical loads. Steel molds in the glass manufacture industry with their functional surfaces simultaneously exposed to the combined thermo-mechanical cyclical loads by liquid glass and corrosive effects of aggressive exhausts of preheating burners are fine examples. This paper is focused on the structural properties and stability of the selected steels under these demanding conditions. The experiment simulated heat load conditions. Two experimental corrosion and heat load resistant materials with high hardness were selected: austenitic steel Dominial-ZF2 ESU, 1.2782 and Toolox 33 and 44 martensitic steels (equivalent to W. Nr. 1.2311, 1.2312, 1.2738, and P20).Web of Science55343643

MODELING OF LUBRICATING LAYER OF STRIP DRESSING WITH THE INFLUENCE OF SURFACE ROUGHNESS

Analizira se utjecaj poprečne hrapavosti trake na procese dresiranja s mazivima. Analiza polazi od Reynoldsove diferencijalne jednadžbe za podmazivanje u koju je ugrađena poprečna hrapavost trake. U proračunu se uzima u obzir i visina maziva na traci te njezin utjecaj na visinu maziva na ulaznom presjeku zone deformacije. Istraživanja su pokazala da poprečna hrapavost ima dvojak utjecaj na visinu maziva na ulaznome presjeku zone deformacije. Za malu hrapavost trake visina mazivoga sloja ima tendenciju laganoga opadanja u odnosu na nominalnu visinu (kada se proces opisuje glatkoćom površina) da bi dalje s porastom hrapavosti debljina mazivoga sloja rasla. Pod nominalnom visinom maziva smatra se slučaj prijelaza konkavne plohe u konveksnu koja djeluje prividno ravnom kao da se proces opisuje glatkoćom površina. Izvršeno je i modeliranje mazivoga sloja za slučaj trenja nedovoljno ovlaženih površina. Okosnicu analize nosila je numerička metoda Monte-Carlo, a izvedeno je i približno analitičko rješenje koje je u usporedbi s numeričkom metodom dalo dobru podudarnost. Ova teorijska istraživanja mogu pojasniti neke pojave podmazivanja u plastičnoj deformaciji metala i činjenicu da oblik hrapavosti trake određuje oblik mazivoga sloja.In the paper the influence of transversal roughness of the strip on dressing processes with lubricants is analyzed. The analysis begins with Reynolds differential equation for lubrication, in which transversal roughness of the strip is incorporated. In the estimation, the height of lubricant on the strip is taken into account, as well as its influence on the height of lubricant at the inlet section of the deformation zone. The research has shown that transversal roughness has a twofold influence on the height of lubricant at the inlet section of the deformation zone. If roughness is small of the strip the height of lubricating layer has a tendency of slight decreasing related to the nominal height (when the process is described by smoothness of surfaces) but with an increase of roughness, the thickness of lubricating layer has a tendency to increase. The nominal height of lubricant is considered to be the case of changing the concave surface into the convex one, which seems to look straight as if the process is described by smoothness of surfaces. Lubricating layer modeling in the friction area on insufficiently lubricated surfaces was also performed. The basis of the analysis was the Monte-Carlo numerical method, and an approximate analytical solution, that gave good match in comparison with the numerical method, was established. The results of this theoretical research can clarify some phenomena of lubrication in plastic deformation of metal and the fact that the shape of strip roughness determines the form of lubricating layer

Predviđanje deformacije i temperature metodom konačnim elemenata (MKE) tijekom valjanja cijevi na pilger – stanu

3D - FEM simulation was used as an efficient tool for description of stress-deformation thermal field at rolling of tubes on a pilgrim mill. The monitored objectives comprised also behaviour of working tools at this rolling. This paper assumes rolling of already pierced thick-walled blank, which passes through the pilgrim stand at simultaneous reduction of thickness of inside and outside diameters at the expense of elongation of initial length. Main attention is focused on the mentioned parameters with respect to various conditions of rolling, such as different heat transfer, different friction or different distance of insertion of the rolled product into the gauge. The input data used at simulation were derived from real conditions of tubemaking.Za prikaz termičkog polja naprezanje – deformacija tijekom valjanja cijevi na pilger - stanu učinkovito je rabljena trodimenzijska metoda konačnih elemenata (3D – MKE). U radu je razmatrano i ponašanje alata tijekom izrade cijevi valjanjem. Pretpostavljeno je valjanje šuplje debelostjene cijevnice na pilger stanu uz istovremeno smanjenje vanjskog i unutrašnjeg promjera na uštrb produljenja početne duljine. Rad se fokusira na navedene parametre obzirom na promjenjive režime valjanja poput različitog prijenosa topline, različitog trenja ili različite udaljenosti uvođenja valjanog proizvoda u uređaj. Ulazni podaci rabljeni u simulaciji odgovaraju onima iz realnog procesa valjanja cijevi