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Sylwia M. Krzemińska, Aleksandra A. Smejda-Krzewicka and Andrzej Leniart

Abstract

The objective of the work was to investigate the possibility of application of carbon and bentonite nanoparticles in carboxylated acrylonitrile-butadiene rubber (XNBR) and the related effects of the nanofillers on the structure, as well as mechanical and barrier properties, of the resulting composites. The composites were designed for use in protective clothing and gloves. XNBR compounds were modified with 2 phr of graphene flakes, graphene oxide, or modified bentonite, and crosslinked with sulfur-accelerator system. Rubber compounds were prepared using a conventional method with a laboratory rolling mill. The composites were studied in terms of structure (WAXS), surface morphology (AFM), the presence of functional groups (ATR-FTIR) barrier properties against chemical substances (mineral oil) and swelling properties, as well as mechanical properties (abrasion resistance and tensile strength). The composites were characterized by very high resistance to oil permeation (breakthrough time >480 min). The type of nanofiller added to the XNBR blend in the amount of 2 phr did not significantly affect mechanical parameters.

Open access

Joanna Paciorek-Sadowska, Marcin Borowicz, Bogusław Czupryński, Ewa Tomaszewska and Joanna Liszkowska

Abstract

A new bio-polyol based on white mustard oil (Synapis alba) and 2,2′-mercaptodiethanol (2,2′-MDE) was obtained. The synthesis was carried out by two-step method. In the first stage, the double bond of the unsaturated fatty acid residues was oxidized, and in the second step the epoxy rings were opened with 2,2′-MDE. The properties of the obtained bio-polyol for application as raw material in polyurethane-polyisocyanurate foams (PUR-PIR) - hydroxyl number, acid number, density, viscosity, pH, water content, FTIR, 1H NMR and 13C NMR were investigated. Based on the obtained results, foaming formulations containing 0 to 0.6 R of the new bio-polyol were prepared. Significant impact of bio-polyol on apparent density, compressive strength, brittleness, flammability, water absorption and thermal conductivity of polyurethane composites were noted. Modified foam had better functional properties than reference foam e.g. lower brittleness, better thermal insulation properties and better fire resistance.

Open access

Sandra Paszkiewicz, Izabela Irska and Elżbieta Piesowicz

Abstract

The phase morphology, thermal behavior and mechanical properties of two series of polymer blends based on ethylene/propylene/diene rubber (EPDM) and amorphous homologues of poly(ethylene terephthalate), i.e. glycol modified poly(ethylene terephthalate) (PETG) and poly(ethylene furanoate) (PEF), were investigated. The morphology of the blends shows a two phase structure in which the minor phase (amorphous polyester) is dispersed as domains in the major (EPDM) continuous matrix phase. Differential calorimetry studies confirmed that both systems were immiscible and exhibits two glass transitions. The melting peak area of EPDM in the blends decreased as the amount of the other component increased. The values of stress at strain of 100% were improved upon the increasing content of PETG in EPDM system, while only slight decrease of this value was observed. Moreover, the strong improvement of hardness and thermo-oxidative stability along with an increasing content of amorphous polyester phase was reported.

Open access

Dongfang Huang, Hong Zheng, Zeyu Liu, Amin Bao and Bo Li

Abstract

Application of 1-butyl-3-metyhlimidazaolium hexafluorophosphate ([C4mim][PF6]), in the extraction of rubidium and cesium from brine solutions using 1,4,7,10,13,16-hexaoxacyclooctadecane (18C6) as extractant was investigated. Parameters that affect the extraction including pH of aqueous phase, equilibration time, dosage of the ionic liquid, phase ratio, concentration of 18C6 were studied. Under the optimal conditions, the single extraction efficiency of rubidium ions and cesium ions were up 84.11% and 94.99%, respectively. The stripping of alkali metal ions from the loaded organic phase with different stripping agents and concentrations were also investigated. The initial value of the K/Cs and K/Rb ratios were 93.0 and 104.3, respectively, which have dropped 91.21% and 88.01%, respectively, after the extraction and stripping experiments. It was taken a big step in the separation and enrichment of cesium (rubidium) ion and potassium ion. The extraction mechanism was revealed most likely to be a cation exchange mode in this system.

Open access

Ehsan Sadeghi Pouya, Hooman Fatoorehchi and Mohammad Foroughi-Dahr

Abstract

The aim of the present work is to study the efficiency of a biocompatible polymer-based adsorbent for the removal of Pb (II) ions whose devastating effects on people’s health is a matter of great concern from aqueous solution. In this study, ethyl cellulose and gamma-Al2O3 nanoparticles/ethyl cellulose electrospun adsorbents were prepared for the batch removal of Pb (II) ions from aqueous solution. Both samples were characterized using contact angle analysis, N2 adsorption/desorption technique, FT-IR and SEM. The Freundlich model (R-square = 0.935 and RMSD (%) = 6.659) and the Dubinin-Radushkevich model (R-square = 0.944 and RMSD (%) = 6.145) were found to be more reliable in predicting the experimental data from the adsorption of Pb (II) ions onto the electrospun gamma-Al2O3 nanoparticles/ethyl cellulose than the Langmuir model (R-square = 0.685 and RMSD (%) = 14.61) and also the Temkin model (R-square = 0.695 and RMSD (%) = 14.38).

Open access

Razvan Hoinaru

Abstract

Corporate reporting is generally perceived as a type of accounting fit for purpose for the 21 century, taking into consideration not only the traditional shareholders’ needs and views but also stakeholders’. Academic literature tends to over-appreciate the non-financial nature of corporate reporting, forgetting that numbers can have their own narratives, which can be read in between the lines. It is true that numbers present certain uncertainties and an extra level of reporting can provide a better interpretation, in a complementary or continuous manner. The present research looks at the current European Union binding legislation and academic and professional judgements towards it. The ultimate questions to be answered is if corporate reporting is improved information? and whose needs are really served: shareholders, the traditional users of accounts, or stakeholders, always hidden, but intuitively taken into account. Findings of the research show that public good is largely perceived as the duty of private interest, as regulated by the public authorities. This mainly happens as shareholders and whoever puts money at risk still are the primarily user group, but the context and consequences of reporting are wider than before. The approach taken by this paper was first of all to discover inside outs of corporate reporting and secondly to look how industry self-regulators interact with public authorities, for the common good. The added value of the present papers is represented by its policy recommendations presented as conclusions.

Open access

Iulian Lita and Tănase Stamule

Abstract

The following study is, in addition to a reassessment of literature and an analysis based on non-parametrical techniques based on linear programming. The analysis based on the Data Envelopment Analisys (DEA) technique will be used to see whether the model that we have used has a significant importance, if there are any substantial differences between the efficiency scores obtained or estimated through various methods. The theoretical part, based on the DEA technique will be analysed under the influence of both the works of Farell(1957), and also Charnes, Cooper, Rhodes(1978), Banker, Charnes, Cooper(1984) and other newer models. The dissolution of efficiency scores obtained through the CRS-DEA model has been studied for a long time into two different components: One is linked with the scale inefficiency and the other one represents the pure technical inefficiency. This dissolution can be done by using the CRS model with technology when not all the companies are operating at the optimum level, i.e. through the simultaneous application on the same set of data of the CRS and VRS models. In this study, the main non-parametrical Data Envelopment Analysis method is presented (Wu, Fan, Zhou, Zhou, 2012; Halkos, Tzeremes, 2009) and its application on a group of 42 companies (The headquarters of a top commercial bank in Romania - S.C. BRD GROUPE SOCIÉTÉ GÉNÉRALE ), based on the information gained in the years 2016-2017. This paper is original because it combines the already developed method with new techniques, in order to link together economic factors and operational research and leaves more room for future researches with the purpose of further assessing and changing the performance of every decisional unit under the influence of the environmental factors.

Open access

Cosmin Ilie

Abstract

The strong emphasis on achieving excellence in the services the museums provide to its target public opens a new road to an area that is not characteristic of traditional museology, namely the journey of innovation. This road to innovation has two pillars: a mature knowledge-based strategy (in response to identified needs of target groups) and the ability to provide education (according to identified needs). Both components are totally dependent on visitors, their needs and their personal or collective experiences. This paper addresses these pillars, considering that education is not a mere accumulation of knowledge, but how the visitor experiences, interacts and learns during his visit. Using the literature review as research methodology, this paper aims to analyze the stakeholders of a museum and to assess their partnerships with other museums, by highlighting the clear advantages of stakeholder involvement in the management system of the museum. The main results shows that museums, as cultural organizations, are a brick at the foundation of economic development in many cities. The involvement and support of the stakeholders is essential for a museum that wants to set and meet appropriate community service goals. Understanding stakeholder`s value is important for effective reporting on the performance of the museum, which transforms and translates through continuous public support for the museum.

Open access

Daniela Yordanova

Abstract

Employability of graduating students is a main precondition for successful university to work transition. Discrepancies on the labour market in terms of demand and supply of highly qualified specialists, increasing requirements and expectations of recently university graduates towards their future jobs, high speed of technological changes resulting in new jobs for which educations is lagging behind and increasing demand for well-developed transferable skills are some of the main challenges which universities are facing nowadays. Thus, their main priorities shall stress on collaboration that is more effective with industrial companies, resulting in contemporary curricula and development and implementation of new forms of cooperation for encouragement of graduating students’ employability. There are some good practices in Bulgaria for common initiatives leading to better professional orientation and further job placing but there is a lack of overall strategic approach in this field. Therefore, there is a necessity of identification and introduction of new forms of cooperation, which will boost partnership and could provide the labour market with more adequate specialists, matching employers’ recent requirements. The purpose of the paper is to provide a methodology of evaluation of problems in university-industry cooperation for encouragement of graduating students’ employability.The main elements of research of cooperation between universities and industry in Bulgaria include (1) description of possible forms of cooperation, (2) evaluation of industry attitudes for cooperation based on 4 criteria - importance, application, interest for participation and awareness of the forms, (3) comparison of opinions of industry and universities in Bulgaria.

Open access

Manuela Liliana Mureșan and Puiu Nistoreanu

Abstract

Tourism has undoubtedly become a factor of economic and social development for everyone in contemporary society. What seems clear is that tourism growth, with the ultimate goal of increasing the socioeconomic level, is a chronological process that requires a certain amount of time before the desired results begin to be observed. Tourism in Romania is an activity linked to the cultural world and natural heritage, as well as the traditions and customs specific to each historical regions of the country. This research makes an analysis of the flow of visitors in Romania, but also an analysis of statistical data provided by the National Statistics Institute of Romania (in the range of 2013 - 2016) with regards to the departures of the Romanian population abroad. We were interested to see what who visits us and what geographical areas they are interested in, and what this means, but especially if this tourist flow analyzed for a period of four years has an impact on the development of the community. The data show that the largest number of arrivals in our country comes from our neighbors, so a tourism promotion strategy aimed at the neighboring markets would be an important factor for the development of tourism communities, all the more so with as are the countries whose main industry generating economic profit is tourism. A long-term national policy of investment and promotion of the destination Romania at international level is necessary, especially since the data obtained clearly tells us that the interest in the Romanian tourism is increasing and this fact leads to the development of the community where it is being developed.