Some Resistive Properties of Novel Oxide Conductors Cu28-m Pbm-x Ax-p Mp Oy (A, M = Ba, Sr, Ag)

Oxide conductors have been prepared starting from the composition with the unit cell formula Cu24Pb4032 which corresponds to the compound with NaCl type structure referred to in the literature as mineral murdochite. The Pb4+ ions are partly substituted by ions of lower valency like Sr2+, Ba2+ and this results in oxidation of copper (Cu2+ Cu3+) which in turn esta blishes mixed valency states (MVS). The general unit cell formula Cu28-m Pbm_x Ax_p Mp Oy can be proposed and variation of parameters m, p, x with permutation of ions A and M results in a pronounced conductivity of samples at room temperature (RT). Some of them exhibit downturn of the electrical resistance (DER) by cooling from 230 K — 350 K. Since the electrical resistance is enhanced by application of higher current densities in the temperature range where the DER occurs, metallic derivatives of murdochite obtained by substitution of Cu and Pb can be used as interesting candidates for the searching of superconductivity (SC) at T > 200 K

Friction at Nanoscale

In many technical fields a contact between two surfaces is very important and often the subject of research. The numerous physical phenomena that occur at the contact between two materials indicate the complexity of the processes that take place at the macro, micro or nanoscale. Therefore, friction, lubrication and wear are the subjects that have been attracting attention for many years, especially as part of tribological investigations. The research has shown that these three components are of fundamental importance for surfaces in contact. The aim of this research is to describe friction, and lubrication as a process to control friction, especially at the atomic level. At the atomic and molecular scale there is a possibility to form very thin film with the property to spontaneously assemble themselves into ordered structures. One of the procedures to make these ultrathin organic films of controlled thickness is to prepare self-assembled monolayers. These monolayers are described as a model system to study boundary lubrication

sl_2 Gaudin model with Jordanian twist

sl_2 Gaudin model with Jordanian twist is studied. This system can be obtained as the semiclassical limit of the XXX spin chain deformed by the Jordanian twist. The appropriate creation operators that yield the Bethe states of the Gaudin model and consequently its spectrum are defined. Their commutation relations with the generators of the corresponding loop algebra as well as with the generating function of integrals of motion are given. The inner products and norms of Bethe states and the relation to the solutions of the Knizhnik-Zamolodchikov equations are discussed.Comment: 22 pages; corrected typo

Public companies fleet cost efficiency management

delatnosti, neminovno se postavlja pitanje položaja koji treba da zauzme podsistem transporta i u okviru toga rad voznih parkova: kao delatnost koja stvara novu vrednost osnovnom sistemu ili kao neizbežan trošak. Značajnu ulogu u tome ima način na koji je definisano korišćenje vozila i kako se odvijaju aktivnosti vezane za vozni park. Predmet ove disertacije su vozni parkovi složenih javnih sistema i analiza uticaja metoda upravljanja troškovima na troškovnu efikasnost. Cilj disertacije je razvoj unapređenog metoda za alokaciju troškova voznih parkova složenih javnih sistema na osnovu prethodno definisanih parametara funkcionisanja sistema koji utiču na način korišćenja vozila i na procese i potprocese podsistema transporta. Metod predstavlja podršku odlučivanju rukovodiocima voznih parkova prilikom optimizacije organizacije, procesa i potprocesa podsistema transporta i korišćenja voznih parkova. U radu je prvo prikazan značaj upravljanja troškovnom efikasnošću u voznim parkovima. Zatim su analizirane karakteristike složenih javnih sistema i tipovi voznih parkova u složenim javnim sistemima, pri čemu je akcenat stavljen na način posedovanja vozila u voznim parkovima. Prikazan je položaj organizacione jedinice transport/vozni park u organizacionoj strukturi složenog sistema, kao i procesi koji se u njoj odvijaju. Prezentiran je unapređeni metod za alokaciju troškova u podsistemima transporta složenih javnih sistema koji se zasniva na obračunu troškova prema aktivnostima i karakteristikama rada voznih parkova. Analizirana je mogućnost njegove primene za potrebe upravljanja troškovnom efikasnošću voznih parkova. Definisani su odgovarajući parametri od uticaja na aktivnosti podsistema transporta i uzročnici troškova u postupku raspoređivanja troškova. Njihovom primenom u metodu određeni su troškovi aktivnosti podsistema transporta. Prilagođena je procedura određivanja troškova prema aktivnostima za primenu u voznom parku javnog preduzeća. Zatim je razvijeni metod primenjen u voznom parku jednog javnog preduzeća u Republici Srbiji. Razvijeni metod, prilagođen datom okruženju, pokazao se pogodnim za korišćenje u velikim voznim parkovima naših javnih preduzeća, i kao međufaza za postepenu primenu sveobuhvatnog sistema za upravljanje troškovima prema aktivnostima.With the contemporary tendencies for business systems to concentrate on their core activities, the question arising indispensably is the position that should be occupied by the transport activity and fleet operation within: is it the activity which provides an added value to the core system or a cost that could not be avoided. The manner of defining the vehicle utilization and the realization of the activities linked to the fleet play an important role in this matter. The object of this dissertation are fleets of complex public systems and the impact analysis of cost management methods on cost efficiency. The objective of the dissertation is the development of cost allocation method within public fleets based on system operation predefined parameters that affect vehicle utilization and transport subsystem processes and sub-processes. The method is a decision support system for fleet managers intended for optimization of the organization, processes and sub-processes of transport and fleet operation subsystems. The dissertation has first highlighted the importance of fleet’s cost efficiency management. Afterwards, the characteristics of complex public systems and types of public fleets were analyzed, with emphasis on fleet ownership. Position of the transport organizational unit/fleet department within the organizational structure of a complex public system has been presented, as well as processes taking place within. An improved fleet cost efficiency management method is then shown within transport subsystems of complex public systems based on Activity Based Costing and fleet operation characteristics . The possibility of its implementation into fleet cost efficiency management has been analyzed. Relevant parameters influencing transport subsystem activities and cost drivers in the cost allocation procedure have been defined. Their usage in this method allowed transport activities’ costs to be determined. Cost determination procedure based on Activity Based Costing in the public companies fleet has been appropriately adapted. The method has been implemented in one public company fleet in the Republic of Serbia. The established method, adapted to such environment, proved to be suitable for use in large fleets of Serbian public companies, and as an intermediate stage for the gradual implementation of a comprehensive system for activity based cost management

Supplementary data for the article: Kodranov, I. D.; Pergal, M. V.; Avdin, V. V.; Manojlović, D. D. Examination of Degradation and Ecotoxicology of Pethoxamid and Metazachlor after Chlorine Dioxide Treatment. Environ Monit Assess 2020, 192 (7), 422. https://doi.org/10.1007/s10661-020-08392-1

Supplementary material for: [https://doi.org/10.1007/s10661-020-08392-1]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/4007

Fleet renewal: An approach to achieve sustainable road transport

With more stringent requirements for efficient utilization of energy resources within the transport industry a need for implementation of sustainable development principles has appeared. Such action will be one of competitive advantages in the future. This is especially confirmed within the road transport sector. A methodology implemented in public procurement procedures for fleet renewal regarding the calculation of road vehicles’ operational lifecycle costs has been analyzed in detail in this paper. Afore mentioned calculation comprises the costs for: vehicle ownership, energy, carbon dioxide and pollutants emissions. Implementation of this methodology allows making the choice of energy efficient vehicles and vehicles with notable positive environmental effects. The objective of the research is to assess the influence of specific parameters of vehicle operational lifecycle costs, especially energy costs and estimated vehicle energy consumption, on vehicle choice in the procurement procedure. The case of urban bus fleet in Serbia was analyzed. Their operational lifecycle costs were calculated and differently powered vehicles were assessed. Energy consumption input values were defined. It was proved that defined fleet renewal scenarios could influence unquestionable decrease in energy consumption