Simulation study of random sequential adsorption of mixtures on a triangular lattice

Random sequential adsorption of binary mixtures of extended objects on a two-dimensional triangular lattice is studied numerically by means of Monte Carlo simulations. The depositing objects are formed by self-avoiding random walks on the lattice. We concentrate here on the influence of the symmetry properties of the shapes on the kinetics of the deposition processes in two-component mixtures. Approach to the jamming limit in the case of mixtures is found to be exponential, of the form: $\theta(t) \sim \theta_{jam}-\Delta\theta \exp (-t/\sigma),$ and the values of the parameter $\sigma$ are determined by the order of symmetry of the less symmetric object in the mixture. Depending on the local geometry of the objects making the mixture, jamming coverage of a mixture can be either greater than both single-component jamming coverages or it can be in between these values. Results of the simulations for various fractional concentrations of the objects in the mixture are also presented.Comment: 11 figures, 2 table

Izbor biomaterijala - višekriterijumska analiza i razvoj sistema za podršku odlučivanju

Community development has led to the increasing use of biomaterials, which are used for making prostheses and implants. The topic of this doctoral dissertation is selection of biomaterials by using multi-criteria decision making methods. First of all the material selection problem, its actuality and methods that used to solve the problem are described. Then the basic principles of multi-criteria decision making theory with specifics of its application for material selecetion are explained. Existing multi-criteria decision making methods are adapted so that they can be successfully and reliably used for the selection of biomaterials. The procedures of three methods used in this dissertation (Extended TOPSIS, Extended WASPAS and Comprehensive VIKOR) as well as methodology for determination of criteria weightings are described in detail. Furthermore it is outlined methods for comparison of solutions obtained by different methods. In the following chapter, basic definitions, terms and requirements regarding biomaterials are listed, which is followed by a detailed review of metallic biomaterials. Three case studies of biomaterials selection by means multi-criteria decision making methods are considered. The first one is selection of biomaterial for bone fixation plates, the second one is biomaterial selection for femoral part of hip prosthesis and the third one is selection of biomaterial for femoral component of knee prosthesis. Finally, it is developed a decision support system (MCDM Solver). in which adapted multi-criteria decision making methods are incorporated. Checking and validation of the developed decision support system is carried out through the use of the previously solved case studies

(Im)possible martyrdom: Masculinity, aging, illness, and death in Tombstone and Logan

The title of this paper alludes to Hannah Arendt's famous claim that in Nazi concentration camps martyrdom was made impossible, for the first time in Western history, by the utter anonymity and meaninglessness of inmates' deaths (Arendt, 2000, p. 133): the paper, in contrast, examines two contemporary films which, while intersecting normative/heroic masculinity with debilitating illness and death, allow for the possibility of martyrdom. Tombstone and Logan, directed by George P. Cosmatos and James Mangold respectively, depict the last days of such pop culture icons of masculinity as John Henry 'Doc' Holliday and James Howlett, aka Logan/Wolverine. The films' thematic focus on the (protracted) ending of life, which is evident not only in the storylines and dialogues but also in the numerous close-ups of emaciated, bleeding, scarred and prostrate male bodies, afflicted with tuberculosis and cancer-like adamantium poisoning, invites, first, a discussion of the relationship between the cinematic representations of normative and disabled masculinities. Specifically, since normative masculinity, as opposed to femininity, is synonymous with physical and mental strength, power and domination - including the control of one's own body - the focus of this discussion is if, and how, the films depict Doc Holliday and Wolverine as feminized by their failing/disobedient bodies, thus contributing to the cultural construction of gender. Secondly, the paper discusses the halo of martyrdom with which the films' dying men are rewarded as emotionally deeply satisfying to the viewer: in Logan and Tombstone, death is not averted but hastened for the sake of friendship, family, and the protection of the vulnerable and the marginalized. While the films offer comforting fantasies of self-sacrifice and dignity-restoring death as an antidote to the brutally depicted aging and illness, the last question to be posed in the paper is whether this (im)possible martyrdom reaffirms normative, ablebodied and dominating masculinity

The effect of architectural façade design on energy savings in the student dormitory

There are many reasons for adequate use of natural light inside students' dormitories. Intensity of light required for student activities and temperature inside the rooms are the major factors for an occupant's comfortable work and life. Design of building façades has a significant impact both on the use of natural light and energy consumption. In this paper, a comparative analysis of student rooms with different orientations and different façade designs was performed in order to investigate what type of refurbishment in the façade is necessary. The goal of the refurbishment was generation of optimal thermal and lighting comfort for students' work with maximal energy saving for a new student dormitory in Nis, Serbia. An analysis of annual energy consumption of the newly designed student dormitory and proposed replacements on the exterior façade was performed by using the software EnergyPlus. Based on the energy consumption analysis it could be concluded that significant energy savings would be possible by upgrading the shading devices across the width of the window. In other words, changing the façade of the dorm could generally improve students' comfort, while the energy costs would be reduced. [Projekat Ministarstva nauke Republike Srbije, br. TR 36037: Development of student dorms in Serbia at the beginning of the 21st century i br. TR 33051: The concept of sustainable energy supply of settlements with energy efficient buildings

Upotreba mikrobnog sirila "Renilaza" u proizvodnji trapista, kačkavalja i bijelog sira u kriškama

Već duže vremena u svetu se osjeća nedostatak telećih želudaca za proizvodnju sirila. Stoga je u posljednjim godinama porastao interes za dobivanje sirila s pomoću mikroorganizama. Pored pomanjkanja sirila i niža cijena mikrobnog sirila razlog su za povećanje interesiranja za sirila proizvedena s pomoću mikroba

Buckets of the bucket wheel excavators: failures and redesign

Design of the buckets of the bucket wheel excavators has to meet the set of the functional requirements imposed by the processes of: (a) soil cutting; (b) filling; (c) transportation of the grabbed soil; (d) emptying. Optimal conduct of each of these processes imposes requirements, which are often in mutual collision. Except functional requirements, bucket structure has to meet, naturally, rigidity as well as strength criterion. During exploitation in harsh working conditions, failures of buckets occur relatively frequently. There are two basic types of bucket failures: structural and technological. In this paper, two bucket structural failures as well as one technological bucket failure are presented. Investigations' results pointed out that structural failures are caused by 'design-in' as well 'manufacturing-in' defects. Technological failure of the bucket was also of the 'design-in' type. Besides that, the redesigned buckets' are presented. Exploitation after the reconstruction fully confirmed the validity of the presented reconstruction design

Buckets of the bucket wheel excavators: failures and redesign

Design of the buckets of the bucket wheel excavators has to meet the set of the functional requirements imposed by the processes of: (a) soil cutting; (b) filling; (c) transportation of the grabbed soil; (d) emptying. Optimal conduct of each of these processes imposes requirements, which are often in mutual collision. Except functional requirements, bucket structure has to meet, naturally, rigidity as well as strength criterion. During exploitation in harsh working conditions, failures of buckets occur relatively frequently. There are two basic types of bucket failures: structural and technological. In this paper, two bucket structural failures as well as one technological bucket failure are presented. Investigations' results pointed out that structural failures are caused by 'design-in' as well 'manufacturing-in' defects. Technological failure of the bucket was also of the 'design-in' type. Besides that, the redesigned buckets' are presented. Exploitation after the reconstruction fully confirmed the validity of the presented reconstruction design

Strength analysis of bucket wheel excavator’s eight wheel equalizing system

This paper presents the results of the study dedicated to the problem of the bucket wheel excavator equalizing system (ES) strength. Finite element analysis of two wheel (TWB), four wheel (FWB) and eight wheel (EWB) bogies were conducted in order to determine weak points in ES structure. Strength and carrying capacity of FWB and EWB structures might be jeopardized due to their insufficient strength under lateral forces acting during curve travel. Severe failure of similar TWB structure is also presented and certain paraleles were made

Strength analysis of bucket wheel excavator’s eight wheel equalizing system

This paper presents the results of the study dedicated to the problem of the bucket wheel excavator equalizing system (ES) strength. Finite element analysis of two wheel (TWB), four wheel (FWB) and eight wheel (EWB) bogies were conducted in order to determine weak points in ES structure. Strength and carrying capacity of FWB and EWB structures might be jeopardized due to their insufficient strength under lateral forces acting during curve travel. Severe failure of similar TWB structure is also presented and certain paraleles were made

Specific Engineering Challenges During the Large-Scale Structures’ Mantling and Dismantling Procedures

Mounting and dismantling of large-scale mechanical systems is a complex engineering challenge due to several factors, such as structural diversity and size of handled structures, limited maneuvering options, and absence of related literature, to name the few, all of which make each problem unique. Numerous disasters throughout the history created a need for a safe approach to the problem of executing such procedures risk-free, while preserving the structural integrity and functionality of the structures. One of the most reliable methods is the application of unique below-the hook lifting devices and the goal of this paper is to present the benefits of their use via two examples. Case 1 deals with dismounting of dated constructions in a densely populated area, with limited structural data provided. Case 2 is focused on mounting of a large-scale roof structure in harsh boundary conditions, with limited maneuvering space. Results presented in this paper represent a contribution to the field of below-the hook lifting devices