The effects of nanoclay on mechanical properties of high density polyethylene and polypropylene materials

Polymeric materials find usage in most places in daily life. Expected features vary depending on the use of these materials. Composite material can be formed by combining one or more different materials. Physical and chemical properties of a new produced composite material can be improved with the addition of additives and fillers to polymer materials. The addition of additives and fillers improve one or more properties at the same time, despite that, it may lead to deteriorate another property. Therefore, it is necessary to investigate the mechanical and thermal properties of these produced composite structures. This study was carried out by nanoclay addition to high density polyethylene (HDPE) and polypropylene (PP) materials. Nanoclay additions were made to the polymer matrix at mass ratios of 5% and 10%. Tensile test, tear test and the Izod impact tests were performed. It has been observed that the tensile strengths of HDPE composites decreased whereas PP composites increased with respect to the pure products. Also, the tear strengths of composites decreased compared to pure products. In the Izod impact tests, all notched specimens were broken. The values of impact strength of the PP composites were not changed in the notched Izod impact tests, whereas the HDPE composites showed a decrease. © 2018 Polish Academy of Sciences Institute of Physics. All rights reserved

Pseudo-spherical submanifolds with 1-type pseudo-spherical Gauss map

In this work, we study the pseudo-Riemannian submanifolds of a pseudo-sphere with 1-type pseudo-spherical Gauss map. First, we classify the Lorentzian surfaces in a 4-dimensional pseudo-sphere $\mathbb{S}^4_s(1)$ with index s, $s=1, 2$, and having harmonic pseudo-spherical Gauss map. Then we give a characterization theorem for pseudo-Riemannian submanifolds of a pseudo-sphere $\mathbb{S}^{m-1}_s(1)\subset\mathbb{E}^m_s$ with 1-type pseudo-spherical Gauss map, and we classify spacelike surfaces and Lorentzian surfaces in the de Sitter space $\mathbb{S}^4_1(1)\subset\mathbb{E}^5_1$ with 1-type pseudo-spherical Gauss map. Finally, according to the causal character of the mean curvature vector we obtain the classification of submanifolds of a pseudo-sphere having 1-type pseudo-spherical Gauss map with nonzero constant component in its spectral decomposition

Utjecaj toplinske modifikacije i ugušćivanja na fizikalna svojstva topolovine

In this study, density, volumetric swelling, mass loss, volume weight, fiber saturation point and water absorption of the poplar wood (Populus usbekistanica) were investigated with the effect of heat modification (HM) and heat-modifi ed densifi cation (HMD). Poplar samples were modified with steam at 120 °C, 160 °C and 200 °C for 1 and 3 h. After heat modification, the samples were compressed in hot press at a temperature of 120 °C, press pressure of 5 MPa and press time of 30 minutes for densification. Physical properties of the samples were determined according to Turkish standards. The results showed that heat modification affected densification and increased density. Densification had a positive effect on oven dry density (D0), oven dry density after soaking (D0S), volume weight (R) and fi ber saturation point (FSP), except for volumetric swelling. Similarly, the densification process had an increasing effect on the water absorption, excluding 360 hours.U ovoj je studiji istražen utjecaj toplinske modifikacije (HM) i ugušćivanja (HMD) na gustoću, volumno bubrenje, gubitak mase, volumnu težinu, točku zasićenosti vlakanaca i upijanje vode drva topole (Populus usbekistanica). Uzorci topolovine modifi cirani su parom pri 120, 160 i 200 °C tijekom jednoga i tri sata. Nakon toplinske modifikacije uzorci su radi ugušćivanja stlačeni u vrućoj preši, pri temperaturi 120 °C, tlaku prešanja 5 MPa i vremenu prešanja 30 minuta. Fizikalna svojstva uzoraka utvrđena su prema Turskim standardima. Rezultati su pokazali da je toplinska modifi kacija utjecala na proces ugušćivanja i pridonijela povećanju gustoće. Ugušćivanje je imalo pozitivan učinak na gustoću topolovine u apsolutno suhom stanju (D0), na njezinu gustoću u apsolutno suhom stanju nakon natapanja (D0S), na volumnu težinu (R) i na točku zasićenosti vlakanaca (FSP), ali ne i na volumno bubrenje. Također, ugušćivanje je znatnije utjecalo na sposobnost upijanja veće količine vode, osim za vrijeme od 360 sati

Bir huzur masalı gibi

Taha Toros Arşivi, Dosya No: 64-Kuzguncukİstanbul Kalkınma Ajansı (TR10/14/YEN/0033) İstanbul Development Agency (TR10/14/YEN/0033

Futurism, Universalism, and the Moral Agency of the Electric Telegraph

Die Idee, dass der elektrische Telegraph in der Lage sei, Grenzen zu beseitigen und nationale wie internationale Konflikte zu überwinden, begleitet seine Geschichte, war aber besonders stark in der Zeit seiner Entwicklung und Ausbreitung über den gesamten Globus. Stimuliert von der Aufmerksamkeit, die die Bemühungen um ein atlantisches Kabel (1857–1866) fanden, wurde dieses Motiv Teil der Popularkultur. Von S. B. F. Morse bis H. G. Wells stellten sich viele vor, dass er Kriege beenden würde, indem er mit den Missverständnissen zwischen Völkern und Nationen aufräumen würde. Nationalismus, Sektierertum und „Partikularismen“ würden verschwinden, eine „universelle Union“ oder ein „Welt-Staat“ würden entstehen. Zentral für diese Annahme war der Glaube, dass der elektrische Telegraph eine große Handlungsmacht habe, nicht nur in Bezug auf soziale, wirtschaftliche und politische Veränderungen, sondern auch für die geistige, moralische und intellektuelle Verbesserung der Menschheit. Wie allerdings schon H. D. Thoreau vorausgesagt hatte, konnte der Telegraph selbst die intellektuelle oder moralische Qualität der Kommunikation nicht verbessern, ohne intelligente und moralische Nutzer würde diese neue Kommunikationsform nur beschleunigen, was die alten Medien, wie etwa die Tageszeitungen, bisher schon getan hatten