Obzirom na obilježavanje 70 godina časopisa, u ovom radu dan je pregled sadržaja časopisa od njegovih početaka odnosno u periodu od 1952. do 1953. godine. U radu se najprije govori o strukturi ...časopisa, zastupljenosti tema po pojedinim radovima, te se daje osvrt na rad Društva u 1953. godini. Također su dana i pitanja čitatelja i odgovori stručnjaka, kao i aktualne vijesti i infromacije iz stručne literature i tiska iz tog perioda.
Considering the 70th anniversary of the journal, this paper provides a review of the contents of the journal from its beginnings, that is, in the period from 1952 to 1953. The paper firstly describes the structure of the journal, then gives the frequency of topics in the published papers, and an overview of the Society's work in 1953. Readers' questions and experts' answers are also given, as well as current news and information from professional literature and press from that period.
A Soviet Journey La Guma, Alex; Lee, Christopher J; Thiong'o, Ngugi wa ...
2017, 2017-04-18
eBook
A Soviet Journey by the South African activist and novelist Alex La Guma (1925-1985) is one of the longest and most substantive accounts of the USSR by an African writer. It is a rare and important ...document of the antiapartheid struggle and the cold war period.
African Consciousness Stone, Leonard
Journal of African American studies (New Brunswick, N.J.),
09/2018, Letnik:
22, Številka:
2/3
Journal Article
Recenzirano
This paper explores African consciousness in terms of conscious moments that regulate and give rhythm to the space of African consciousness. That is, an African consciousness insofar as it unfolds ...within an experience of the African moment, within terms of urban spaces and realization and estrangement. A microanalysis of the processes of African consciousness within a strategy aims to re-construct, to redirect, and combatatively recenter African subject as a sovereign entity. This is, to strategically essentialise African subject. This subject is also gathered especially under the heading of the African-look-on-African-look and estranged African consciousness using La Guma as a major literary reference point. The intention of this micro-analysis is to garner an essentialist understanding of African subject as a presence-to-African others. An African consciousness in which the solid structure of African experience, intention, and expectation are centered.
This article is a text/context piece that republishes and examines a speech by the South African writer and activist Alex La Guma (1925-1985) in his capacity as the secretary general for the ...Afro-Asian Writers Association (AAWA). This speech was delivered in Tashkent, Uzbekistan, to mark the 25th anniversary of the organization. As a primary source, it details the ambitions and politics of the AAWA as well as summarizing La Guma's own activities and beliefs, providing a panoramic view of the political and cultural world to which he belonged. La Guma was a true internationalist: the document captures his spirit toward the end of his life. This version was published in 1985, the year of his death, in the AAWA journal Lotus: Afro-Asian Writings.
Recikliranje otpadne gume devulkanizacijom Ptiček Siročić, Anita; Florijanić, Franjo; Šokman, Maja ...
Kemija u industriji,
06/2019, Letnik:
68, Številka:
5-6
Journal Article, Paper
Recenzirano
Odprti dostop
Posljednjih nekoliko desetljeća polimeri i polimerni materijali postali su neizostavni dio različitih grana industrije i svakodnevnog života. Zbog vrlo raširene upotrebe elastomera nastaju velike ...količine gumenog otpada, što je opterećenje za okoliš te zahtijeva posebne mjere zbrinjavanja kako bi se smanjio njihov negativan utjecaj na okoliš. Uzorci polimernih mješavina na bazi prirodnog (NR) i stiren-butadienskog kaučuka (SBR) pripremljeni su u dvije serije s ciljem ispitivanja mehaničkih (prekidna čvrstoća, prekidno istezanje, ispitivanje čvrstoće na zarez) i reoloških svojstava te krajnje upotrebe u proizvodnji gumenih pružnih prijelaza. Prva serija uzoraka pripremljena je s gumenim prahom, a u drugu seriju umiješan je devulkanizirani gumeni prah. Uzorci su miješani na laboratorijskom mikseru te homogenizirani na laboratorijskom dvovaljku, a proces prešanja proveden je na hidrauličkoj preši. Dobiveni rezultati ispitivanja mehaničkih i reoloških svojstava pokazali su da je za NR/SBR polimernu mješavinu koja bi se upotrebljavala za pružne prijelaze znatno bolja opcija dodatak gumenog praha koji je dodatno devulkaniziran.
Environmental protection requires constant improvement of quality and the environmental management system in accordance with the international standards and laws in order to reduce human impact on the environment and responsibly manage natural resources. Environmentally acceptable recycling of waste tires and other rubber products is one of the biggest ecological challenges today. Landfilling or dumping of tires causes serious long-term pollution. The lack of alternatives for tire recycling increases their disposal in landfills. Recycling is currently the most effective way to improve the sustainability of the environment. The purpose of this work was to determine the optimal composition of the rubber blend to be used for rubber track crossings production, and to examine the ratio of individual components,
i.e.
, milled recycled tires, and milled and devulcanized tires in order to determine which option is more environmentally friendly and financially viable. In the first series of samples, recycled rubber powder (milled recycled tires) was mixed with a polymer blend of natural rubber and styrene-butadiene rubber, while the second series was milled and the devulcanized tires mixed with natural rubber and styrene-butadiene rubber. Rheological and mechanical properties of all the samples were measured according to appropriate standards. The results showed that an increase in the ratio of rubber powder increased the values of minimal rotation resistance and proportionally reduced the maximum rotation resistance. Minor deviations in the values of the vulcanization rate indicated that various ratios of added rubber powder had no significant effect on the rate of vulcanization of individual samples. The results of the viscosity measurement indicated a proportional increase in the values of initial rotation resistance with the increase in the ratio of added rubber dust compared to the samples prepared with milled and devulcanized rubber, whereby a proportional decrease in value was apparent. From the results of mechanical properties, observed was a reduction in tensile strength and elongation at break values for both series of tested samples. The same behaviour was also observed for the tear strength values. With the addition of different filler ratios, the hardness value for both series of prepared samples had reduced, while the values of the rebound elasticity differed slightly. Significant reduction in hardness value was evident for the samples prepared with the milled and devulcanized rubber powder, which could be attributed to the use of a softener during devulcanization of the material. It can be concluded that NR/SBR polymer blends can be mixed with various recycled rubber materials whereby the devulcanization process enables better mechanical and rheological properties, thus, used rubber tires can be effectively removed from the environment.
Rubber is important in many engineering applications because of its unique properties. These properties must be measured with appropriate test methods developed specifically for this class of ...materials. This book provides, in one volume, comprehensive coverage of the procedures for measuring the whole range of the physical properties of rubber. This new edition presents an up-to-date introduction to the standard methods used for testing, quality control analysis, product evaluation, and production of design data for rubber and elastomers. Factors to be incorporated in the revision include the effects of newer instrumentation, the cutting back of laboratory staff, increased demands for formal accreditation and calibration, trend to product testing, overlap of thermoplastic elastomers with plastics and increased need for design data.
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