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Effect of particle roundness and morphology on the shear failure mechanism of granular soil under strip footing
Babak Karimi Ghalehjough, Suat Akbulut, Semet Çelik, 2018, original scientific article

Abstract: This study investigates the effect of particles roundness and morphology on the shear failure mechanism of soil. A strip footing was modeled under laboratory conditions. Calcareous soil was tested with three roundness classes: angular, rounded and well-rounded shapes with sizes of 0.30 mm to 4.75 mm. These were divided into six different groups at three relative densities of 30%, 50% and 70%. A series of photographs was taken during the tests and analyzed using the particle image velocimetry (PIV) method to understand the soil-deformation mechanism. The results showed that increasing the sample sizes increased the affected area of the soil. At the same time, increasing the relative density caused a punching failure mechanism that went towards the general failure. The shear failure mechanism of the soil changed from general toward punching shear failure with increasing particle roundness. This effect was larger with the smaller materials. Underneath the affected layers of soil, the angular samples were deeper than the rounded and well-rounded samples. The affected depth in the angular soil was approximately 1.5B in the smallest size group. This was more than 3B and near 4B in the largest size group. Both the sides and the underlying soil layers should be considered on angular soils. The area under the footing becomes more important than the side parts after increasing the roundness of the particles.
Keywords: particle roundness, morphology of particles, shear failure mechanism, strip footing, PIV method, ultimate bearing capacity
Published in DKUM: 11.10.2018; Views: 1228; Downloads: 428
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The meaning function of the case particle ʃi in the Tsuken Island dialect of Japanese considered from the perspective of collocative relations
Satomi Matayoshi, 2010, original scientific article

Abstract: This paper describes the case particle ʃi in the Tsuken Island dialect of Okinawa, Japan. This particle has a similar function to the preposition to in the English language. It is thought that ʃi is equivalent to case particles ni or e in the Japanese standard language, but its origin is not clear. ʃi has not only the function of ni or e, but also one of the functions of Standard Japanese made. It seems that ʃi developed in the Tsuken Island dialect.
Keywords: Japanese, collocations, case particles, grammar, geolinguistics
Published in DKUM: 05.02.2018; Views: 780; Downloads: 360
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Effect of drying parameters on physiochemical and sensory properties of fruit powders processed by PGSS-, vacuum- and spray-drying
Urban Feguš, Uroš Žigon, Marcus Petermann, Željko Knez, 2015, original scientific article

Abstract: Aim of this experimental work was to investigate the possibility of producing fruit powders without employing drying aid and to investigate the effect of drying temperature on the final powder characteristics. Raw fruit materials (banana puree, strawberry puree and blueberry concentrate) were processed using three different drying techniques each opera- ting at different temperature conditions: vacuum-drying (–27–17 °C), spray-drying (130–160 °C) and PGSS-drying (112–152 °C). Moisture content, total colour difference, antioxidant activity and sensory characteristics of the proces- sed fruit powders were analysed. The results obtained from the experimental work indicate that investigated fruit pow- ders without or with minimal addition of maltodextrin can be produced. Additionally, it was observed that an increase in process temperature results in a higher loss of colour, reduced antioxidant activity and intensity of the flavour profile.
Keywords: particles from gas saturated solutions drying, vacuum-drying, spray-drying, sensory evaluation, fruit powders
Published in DKUM: 18.08.2017; Views: 1047; Downloads: 362
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Isospin violating decays of positive parity Bs mesons in HMχPT
Svjetlana Fajfer, Anita Prapotnik Brdnik, 2016, original scientific article

Abstract: Recent lattice QCD results suggest that the masses of the first two positive parity Bs mesons lie below the BK threshold, similar to the case of D∗s0(2317)+ and Ds1(2460)+ mesons. The mass spectrum of Bs mesons seems to follow the pattern of a Ds mass spectrum. As in the case of charmed mesons, the structure of positive parity Bs mesons is very intriguing. To shed more light on this issue, we investigate the strong isospin violating decays B∗0s0→B0sπ0, B0s1→B∗0sπ0, and B0s1→B0sππ within heavy meson chiral perturbation theory. The two-body decay amplitude arises at tree level and we show that the loop corrections give significant contributions. On the other hand, in the case of three-body decay B0s1→B0sππ the amplitude occurs only at loop level. We find that the decay widths for these decays are Γ(B0s1→B0sππ)∼10−3 keV, and Γ(B∗0s0→B0sπ0)≤55 keV, Γ(B0s1→B∗0sπ0)≤50 keV. More precise knowledge of the coupling constant describing the interaction of positive and negative parity heavy mesons with light pseudo-scalar mesons would help to increase the accuracy of our calculation.
Keywords: physics, elementary particles, B mesons, decays
Published in DKUM: 26.06.2017; Views: 750; Downloads: 116
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The influence of the morphology of iron powder particles on their compaction in an automatic die
Borivoj Šuštaršič, Matjaž Godec, Črtomir Donik, Irena Paulin, Srečko Glodež, Marko Šori, Milan Ratej, Nada Javornik, 2015, professional article

Abstract: Fe- and steel-based powder metallurgy (P/M) products, such as steel gears, spurs, locking mechanisms, porous filters, sliding bearings and bushes, as well as other machine parts and structural elements, are mainly produced with the so-called conventional sintering technology. It is the most efficient technology for the mass production of small, complex, functional and structural parts. Therefore, it is the most convenient and popular among all of the P/M technologies. The most important end-user of sintered parts is the automotive industry. However, small, complex, sintered parts can also be frequently used in the furniture and household industries, precise mechanics, articles for recreation and sports. A fine, iron-based powder mixture or prealloyed powder is first automatically uniaxial-die compacted (ADC) into the final shape of the product with a mechanical or hydraulic press and then sintered in a protective atmosphere at approximately 1100 °C. The metal powder mixture must have the appropriate engineering properties given by the chemistry and particle morphology, enabling a fast and reliable die-compaction process. The most important are a high tap density, a good powder flowability and a low compressibility. All this gives the green compacts an appropriate final shape with a smooth surface, a relatively high and uniform green density, as well as a green strength without internal flaws and cracks. In the case of very small two-or-more-heights products, for example, spur gears with a low module, it is very difficult to obtain a uniform green density at acceptable compaction pressures. Often small cracks are formed at height crossings and big differences in the green density appear in smaller or thinner regions. In the frame of our investigation we analysed the influence of the selected prealloyed commercial iron powder’s morphology and its technological properties on automatic die compaction, as well as the sintering process in the case of small two-level sintered gear dimensions of 5/40–7/10×7mm with module m = 0.5. The original iron powder was sieved and the finest powder particle fraction (< 45 µm) was compared with the original powder mixture considering ADC and sintering process. It was found that the selection of the finer powder mixture could not contribute to the improvement in the overall ADC process, as well as a better green compact. In the present paper the results of our investigations are presented and the reasons why a finer powder mixture cannot contribute much to an improvement of the conventional sintering process.
Keywords: Fe-based alloy powders, particles, morphology, microstructure, automatic die compaction, sintering
Published in DKUM: 27.03.2017; Views: 1075; Downloads: 338
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Experimental analysis of the impact of particles on the cavitating flow
Boštjan Gregorc, Andrej Predin, Drago Fabijan, Roman Klasinc, 2012, original scientific article

Abstract: The purpose of this paper is to present an analysis of the impact of solid particles on the development of cavitating flow conditions around a hydrofoil. Experimental studies have been conducted in a cavitation tunnel with three different mixtures of particles and water. We used a particle-like properties, such as are found in river water, and with increasing mass concentration. We performed measurements of torque and the relative noise in the hydrofoil. The point in the formation of vapour phase on the hydrofoil and the pronounced frequency effect were determined by measuring the relative noise. Based on the analysis the results show that the particles increase the intensity and extent of cavitation.
Keywords: particles, cavitation, noise, measurements
Published in DKUM: 10.07.2015; Views: 5609; Downloads: 86
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Pentaquarks and the mass spectrum of the elementary particles of the standard model
Leila Marek-Crnjac, 2006, original scientific article

Abstract: Predstavljene so nove izrazitve matematičnega upanja mase pentakvarka. Možna povezava med Higgsovimi masami in maso pentakvarka je bila raziskana (El Naschie M. S.: Pentaqkvarkovo masno pravilo vsote in Higgsovi delci). Higgsove mase in pentakvarkove mase se lahko izrazijo s supersimetrično konstanto, z nesupersimetrično konstanto in tudi z napovedanim številom elementarnih delcev standardnega modela ▫$N(MS) approx 69$▫. Teoretične napovedi masnega spektra elementarnih delcev standardnega modela so prikazane v tabeli skupaj z razcepitvenimi faktorji.
Keywords: pentakvark, Higgsov delec, masni spekter, elementarni delci standardnega modela, super simetrična konstanta, pentaquark, Higgs particle, mass spectrum, elementary particles of the standard model, super symmetric coupling constant
Published in DKUM: 10.07.2015; Views: 986; Downloads: 86
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Air-release and solid particles sedimentation process within a hydraulic reservoir
Vito Tič, Darko Lovrec, 2013, original scientific article

Abstract: Contaminant in a hydraulic fluid is broadly defined as any substance that impairs the proper functioning of a hydraulic system. Hydraulic fluid can be contaminated by air, particles, water, and foreign fluids. Fluid contamination can cause numerous problems including component damage, unacceptable noise, poor component response and severe fluid degradation. This paper focuses on two major contaminants that should be considered when designing a hydraulic reservoir - air and particle contamination. A proper reservoir design can prevent the occurrence of air and solid contaminants within the hydraulic system and reduce their negative effects. A hydraulic reservoir should be designed in such a way as to stabilize and direct the oil flow inside the reservoir, so that the fluid has enough time to release air bubbles and to deposit solid particles. In order to visualize and understand flow patterns inside the reservoir, all the advantages of using simulation techniques within the field of reservoir design will be shown. This paper investigates the trajectories of solid and gaseous particles within a hydraulic reservoir, which are based on simulated transient phenomena using the Ansys Workbench. The results obtained focus on the sedimentation of solid particles and the elimination of gaseous particles within a hydraulic reservoir.
Keywords: hydraulic reservoir, air bubbles, solid particles, simulation, trajectories
Published in DKUM: 10.07.2015; Views: 1128; Downloads: 121
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Liquid crystal - anisotropic nanoparticles mixtures
Vlad Popa-Nita, Matej Cvetko, Samo Kralj, 2011, independent scientific component part or a chapter in a monograph

Keywords: liquid crystals, nano particles, phase behavior
Published in DKUM: 07.06.2012; Views: 1499; Downloads: 103
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