Low-temperature tension properties of glass-epoxy composite materials

Predmet i cilj ispitivanja prikazanih u ovom radu predstavlja određivanje zatezne čvrstoće (Rm) i modula elastičnosti (EJ staklo-epoksi kompozitnih materijala ispitivanjem na zatezanje na dve različite temperature (t=20°S i t=-50°S). Ispitivanja su izvedena prema standardu na staklo-epoksi kompozitnom materijalu različitih struktura (dve specifične težine ojačanja 210 g/m2H 550 g/m2) i orijentacija ojačanja (0°/90° i ±45°). Doprinos predstavlja i mikromehanička analiza na prelomnim površinama izvedena na stereo i elektronskom mikroskopu kojom se došlo do stvarnih modela nastanka i razvoja oštećenja pri izvedenim ispitivanjima.The aim of this paper was to present the determination of tensile strength Rm and modulus of elasticity Et of glass-epoxy composites at two different temperatures (at room temperature t=20°C, and at t =-50°C). Standard mechanical testing was carried out on glass woven-epoxy composite material with different structures (two specific weights of reinforcement, 210 g/m2 and 550 g/m2) and orientations (0°/90° and ±45°). Micromechanical analysis of failure was performed on a stereo microscope and SEM in order to determine real models and mechanisms of crack

Through thickness optimal design of glass-epoxy composite pressure vessel

Mehaničko opterećenje kod posuda pod pritiskom uglavnom potiče od pritiska (unutrašnjeg ili spoljnjeg), kome je posuda izložena. Napon koji se usled ovakvog opterećenja javlja menja se po debljini zida. Zahvaljujući specifičnostima svoje strukture, korišćenjem kompozitnih materijala u izradi posuda pod pritiskom obezbeđuje se niz prednosti kako u oblasti tehnologije izrade, tako i u toku same eksploatacije, u odnosu na neke druge konstruktivne materijale. Njihovo oblikovanje po želji omogućava da se na taj način duž debljine ostvari optimizacija strukture. Predmet i cilj ovog rada predstavlja proračun i prikaz numeričkog modela kojim su se simulirali različiti pritisci, za različite debljine i strukture zida posude od staklo-epoksi kompozitnog materijala. Na taj način se mogu dobiti optimalne strukture za različite radne pritiske kojima posude u eksploataciji mogu biti izložene.Mechanical loading of pressure vessels mainly comes from pressure (inner and outer) under which is vessel subjected. Tension which appears changes according to the thickness of the wall. Thanks to the its specific structure, by the usage of composite materials in pressure vessels a lot of advantages are got in the field of technology of making, and during the usage, in comparison to some other constructive materials. Their shaping by the need makes it possible to optimize the structure along the thickness. The subject and aim of this work represents calculation and description of numeric model with which the different cases of the work of inner and outer pressure were simulated, for the different thickness of the wall of the pressure vessel of glass epoxy composite. In that way we come to optimal structure of material for different working pressures under which the vessels can be submitted during the usage

Through thickness optimal design of glass-epoxy composite pressure vessel

Mehaničko opterećenje kod posuda pod pritiskom uglavnom potiče od pritiska (unutrašnjeg ili spoljnjeg), kome je posuda izložena. Napon koji se usled ovakvog opterećenja javlja menja se po debljini zida. Zahvaljujući specifičnostima svoje strukture, korišćenjem kompozitnih materijala u izradi posuda pod pritiskom obezbeđuje se niz prednosti kako u oblasti tehnologije izrade, tako i u toku same eksploatacije, u odnosu na neke druge konstruktivne materijale. Njihovo oblikovanje po želji omogućava da se na taj način duž debljine ostvari optimizacija strukture. Predmet i cilj ovog rada predstavlja proračun i prikaz numeričkog modela kojim su se simulirali različiti pritisci, za različite debljine i strukture zida posude od staklo-epoksi kompozitnog materijala. Na taj način se mogu dobiti optimalne strukture za različite radne pritiske kojima posude u eksploataciji mogu biti izložene.Mechanical loading of pressure vessels mainly comes from pressure (inner and outer) under which is vessel subjected. Tension which appears changes according to the thickness of the wall. Thanks to the its specific structure, by the usage of composite materials in pressure vessels a lot of advantages are got in the field of technology of making, and during the usage, in comparison to some other constructive materials. Their shaping by the need makes it possible to optimize the structure along the thickness. The subject and aim of this work represents calculation and description of numeric model with which the different cases of the work of inner and outer pressure were simulated, for the different thickness of the wall of the pressure vessel of glass epoxy composite. In that way we come to optimal structure of material for different working pressures under which the vessels can be submitted during the usage

emoji2vec: Learning Emoji Representations from their Description

Many current natural language processing applications for social media rely on representation learning and utilize pre-trained word embeddings. There currently exist several publicly-available, pre-trained sets of word embeddings, but they contain few or no emoji representations even as emoji usage in social media has increased. In this paper we release emoji2vec, pre-trained embeddings for all Unicode emoji which are learned from their description in the Unicode emoji standard. The resulting emoji embeddings can be readily used in downstream social natural language processing applications alongside word2vec. We demonstrate, for the downstream task of sentiment analysis, that emoji embeddings learned from short descriptions outperforms a skip-gram model trained on a large collection of tweets, while avoiding the need for contexts in which emoji need to appear frequently in order to estimate a representation