1,720,959 research outputs found
Saplākšņa stiprības palielināšana ar kaņepju šķiedru
No full textRakstā ir atspoguļoti risinājumu meklējumi stiprības palielināšanai saplākšņa kompozītmateriālos to sastāvā iekļaujot citas komponentes, rezultātā izveidojot jaunu materiālu ar augstākām fizikāli mehāniskām īpašībām.
Cilvēcei arvien vairāk apzinoties savas rūpnieciskās un saimnieciskās darbības sekas, pēdējos gados liela uzmanība tiek pievērsta tam, kādas sekas tā var atstāt uz apkārtējo vidi. Tātad, izstrādājot jaunu produktu, būtiska ir pielietojamo materiālu un izejvielu izvēle un to reciklizācija
Autors ir veicis eksperimentu saplāksni papildinot ar kaņepju šķiedru un no tās izgatavotu tehnisko audumu
Saplākšņa un liekti līmētās koksnes konstrukcijās izmantoto līmju īpašību uzlabošana
No full textRakstā ir atspoguļoti risinājumu meklējumi saplākšņa un liekti līmētās koksnes konstrukciju stiprības palielināšanai modificējot pielietotās līmes sastāvu
Autors ir veicis eksperimentu karbomīd - formaldehīda līmi papildinot ar polivinilacetāta līmi
Saplākšņa un liekti līmētās koksnes konstrukcijās izmantojama līmju maisījuma komponentu savstarpējo attiecību noteikšana
No full textRakstā ir atspoguļoti saplākšņa un liekti līmētās koksnes konstrukcijās pielietojama līmes maisījuma optimālo kokmponentu attiecību iegūšana.
Autors ir veicis eksperimentus, modelējot karbomīd - formaldehīda līmes, cietinātāja un polivinilacetāta līmes savstarpējās attiecības.
Veikto eksperimentu un aprēķinu rezultātā ir atrasts optimāla divkomponentu karbamīdsveķu līmes „Casco Adhesives' UF 1274” ar cietinātāju 2545 un firmas KLEIBERIT polivinilacetāta D3 grupas „Tempo 303” līmes maisījuma attiecība
Aрмированиe березовой фанеры волокнами конопли
No full textВ статье отражены поиски решения задачи увеличения прочности клееной фанеры, армированной волокнами конопли. Показана принципиальная возможность получения нового экологичного материала с повышенными прочностными характеристиками
Biroja krēsla dizains un ergonomikas principi
No full textPirms uzsākt krēsla dizaina veidošanu, dizainerim ir jāņem vērā daudz un dažādi faktori, kas spēj krēslu padarīt ērtu un komfortablu jebkuram lietotājam. Ir skaidrs, ka grūti radīt produktu, kas būtu piemērots jebkuram cilvēka auguma tipam - gariem vai īsiem, slaidiem vai apaļākiem. Tieši tādēļ ir veikta izpēte par galvenajiem faktoriem, kas ietekmē krēsla ērtumu- sēdēšanas procesa dinamika, sēdekļa augstums, sēdekļa dziļums, sēdekļa atzveltne, roku balsti un virsmas apšuvums
Birch Plywood Composite Material with Hemp Fibre Reinforcement
No full textWith growing volumes of utilisation of traditional natural resources, increasing attention is given to new environmentally friendly materials. Worldwide, work is under way on obtaining new materials and upgrading the properties of the already existing ones. New material compounds are created; as a result, composite materials with higher physico-mechanical and service properties have been developed. One of such promising composite materials is plywood, which makes it possible, due to its constructive structure, to reach an enhanced mechanical strength. With increasing application of plywood in the national economy, it becomes necessary to enhance its physico-mechanical properties and to decrease the production costs. Plywood with different coats, varying their surface physical properties, is developed and introduced in production. In industry, plywood coating with different non-wood materials is widely used. An alternative for the so far used methods is the enhancement of the plywood strength with fibre materials of natural origin. The objective of the study was, using a bicomponent binder, to mutually compare the effect of the long fibres of dried hemp and hemp yarn woven technical fabrics on the changes in the physico-mechanical properties of the plywood composite material. It is shown that, for the composite material with the hemp technical textile introduced in its matrix, bending strength index, in comparison with that for the control sample, increases by 21.8 % and modulus of elasticity in static bending increases by 23 %. However, introducing individual hemp fibres, these strength indices are lower. Summarising the obtained results, it may be concluded that, in the future experiments, it will be necessary to investigate the physico-mechanical properties of plywood composite materials, in the matrix of which a technical textile made from hemp is introduced, changing its parameters and the location in different layers of the composite material, as well as the glue, tree species and compressing pressure
Feasibility of Reinforcing Birch Plywood with Hemp Fibres
No full textThe present paper reflects searches for solving the problems of enhancing the strength of plywood, reinforced with hemp fibres. A radical possibility of obtaining a new environmentally friendly material with enhanced strength characteristics is shown. The modern developing society has faced the problem of ever increasing demands for the energy intensity of production and the limited potentialities of meeting them. Recently, the worldwide demand for the sources of natural renewable resources has grown, governed by the energy saving and environmentally friendly technologies of their production, and the feasibility of their processing to environmentally friendly, biodegradable materials with a high added value due to the decrease of material and energy costs. One of such resources is hemp, which is rather profitable, requires much less amounts of artificial fertilisers than other cultures, has a favourable effect on the agroecosystem, improves the soil structure, and inhibits weeds, pests and diseases. Hemp fibre is one of the strongest natural fibres and its characteristics (high tensile strength, wet state strength, etc.) make it technically feasible for the production of different industrial products.
It is shown that the reinforcement of birch five-layer plywood by hemp textiles with a cell size of 8 mm makes it possible to produce an environmentally friendly composite material. Optimal ratios of the components and the binder for producing a composite material of birch plywood, reinforced by hemp textiles, with enhanced mechanical characteristics in bending σbend up to 13.2 % and modulus of elasticity up to 10.3 % have been found. The given composite material can be used for the production of curved-glued furniture and other goods from plywood
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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