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Wyszukujesz frazę "mechanical loss" wg kryterium: Temat


Wyświetlanie 1-15 z 15
Tytuł:
Influence of hardness on mechanical properties of elastomers
Autorzy:
Ochelski, S.
Bogusz, P.
Kiczko, A.
Powiązania:
https://bibliotekanauki.pl/articles/246003.pdf
Data publikacji:
2010
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
experimental research
elastomers
mechanical properties
relative damping coefficient
mechanical loss angle
Opis:
In this paper, elastomers with different hardness factors were examined to evaluate the influence of the hardness on their mechanical properties. The following hardness numbers, measured in Shore A hardness scale, were investigated: 40; 60; 70 and 90°. Basic mechanical tests i.e. axial tension and axial compression have been performed in order to calculate elastic properties and stress values corresponding to the fixed strains: epsilon = 0.2; 0.3 and 0.5. The sigma (epsilon) dependences from the tension and compression tests are nonlinear and have different shapes. The tension plot can be described by a convex parabola, while the compression curve can be approximated by a concave one. dynamic load tests with loading freąuencies 0.01; 0.1; 1.0 and 3,OHz were performed in order to determine the hysteresis loop and to obtain force and displacement dependences in time. From those results the following factors were calculated: relative damping coefficient and mechanical loss angle, as well as their dependence on load frequencies. The influence of hardness on both in-phase and out-of-phase components of normal modulus were investigated. The sensitivity of the examined elastomers to the loading rate was also investigated.
Źródło:
Journal of KONES; 2010, 17, 1; 317-325
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Balancing energy processes in turbine engines
Autorzy:
Balicki, W.
Głowacki, P.
Szczeciński, S.
Korczewski, Z.
Kozakiewicz, A.
Szczeciński, J.
Powiązania:
https://bibliotekanauki.pl/articles/258928.pdf
Data publikacji:
2014
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
turbine engines
aeronautic and marine propulsion systems
energy balance
mechanical loss
Opis:
The article discusses the issue of balancing energy processes in turbine engines in operation in aeronautic and marine propulsion systems with the aim to analyse and evaluate basic operating parameters. The first part presents the problem of enormous amounts of energy needed for driving fans and compressors of the largest contemporary turbofan engines commonly used in long-distance aviation. The amounts of the transmitted power and the effect of flow parameters and constructional properties of the engines on their performance and real efficiency are evaluated. The second part of the article, devoted to marine applications of turbine engines, presents the energy balance of the kinetic system of torque transmission from main engine turbines to screw propellers in the combined system of COGAG type. The physical model of energy conversion processes executed in this system is presented, along with the physical model of gasodynamic processes taking place in a separate driving turbine of a reversing engine. These models have made the basis for formulating balance equations, which then were used for analysing static and dynamic properties of the analysed type of propulsion, in particular in the aspect of mechanical loss evaluation in its kinematic system.
Źródło:
Polish Maritime Research; 2014, 4; 48-56
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation of physical and dynamic mechanical properties of coconut husk ash (CHA) reinforced polyester composites
Autorzy:
Ipilakyaa, Tertsegha
Tuleun, Livinus
Sule, Terngu
Powiązania:
https://bibliotekanauki.pl/articles/1819156.pdf
Data publikacji:
2020
Wydawca:
Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:
dynamic mechanical analysis
sieve analysis
storage modulus
loss modulus
mechanical loss factor
dynamiczna analiza mechaniczna
analiza sitowa
moduł zachowawczy
moduł stratności
współczynnik stratności mechanicznej
Opis:
The evaluation of physical and dynamic mechanical analysis (DMA) properties was carried out on a developed Coconut Husk Ash Reinforced Polymer Composite. Sieve analysis of pretreated coconut husk ash was done to obtain 75 μm, 150 μm and 300 μm particles sizes. These particles were used at varying compositions of 5%, 10%, 15%, 20% and 25% as reinforcements for polyester composites. The catalyst and accelerator used were Methyl Ethyl Ketone Peroxide and Cobalt Naphthenate respectively. The densities of the evaluated composites made with 150 μm particles were found to be less dense with values ranging from 0.9792 g/cm3 to 1.2561 g/cm3 than those made with 75 μm and 300 μm. The results also show that the percentage water absorbed by samples increased, ranging from 0 to over 2000 E’/MPa for all percentage reinforcements of coconut husk ash, with an increase in the duration of immersion of the samples in distilled water. However, 25% reinforcement had better results for all particle sizes. There were obvious variations of storage modulus, loss modulus and mechanical loss factor with percentage weight of reinforcement, temperature and frequency. The composite with 15%reinforcement displayed better results. The composite shows promising results as a material for interior components in aerospace and automobile industries.
Źródło:
Journal of Mechanical and Energy Engineering; 2020, 4, 4; 315--324
2544-0780
2544-1671
Pojawia się w:
Journal of Mechanical and Energy Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Binding force and mechanical strength of rice grain
Autorzy:
Szot, B.
Ferrero, A.
Molenda, M.
Powiązania:
https://bibliotekanauki.pl/articles/24123.pdf
Data publikacji:
1998
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:
physical loss
binding force
Italy
strength property
crop loss
harvest
mechanical strength
mechanical property
rice grain
Źródło:
International Agrophysics; 1998, 12, 3
0236-8722
Pojawia się w:
International Agrophysics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A study on damage to PLA knitted fabrics during scouring and bleaching
Autorzy:
Baig, G. A.
Carr, C. M.
Powiązania:
https://bibliotekanauki.pl/articles/778625.pdf
Data publikacji:
2014
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
PLA
Scouring
Bleaching
Weight loss
mechanical properties
SEM
Opis:
Ingeo® PLA (polylactic acid) knitted fabric was scoured through an exhaust technique. The scouring was carried out with sodium carbonate in the presence of a detergent at various concentrations and temperatures. The scoured fabric was bleached with various oxidative bleaching agents. Bleaching was carried out with hydrogen peroxide, sodium chlorite and sodium hypochlorite. Hydrogen peroxide was applied by exhaust and cold pad batch (CPB) techniques. It was observed that during scouring PLA fabric was degraded at high alkali concentrations and processing temperatures. The scouring temperature above 60oC proved to be deleterious due to the scouring solution penetrating into the polymer structure and damaged the fiber. Sodium chlorite and sodium hypochlorite caused little damage to the mechanical properties of PLA. Hydrogen peroxide when applied by the CPB technique did not reduce strength appreciably but when applied by the exhaust technique decreased the strength significantly. SEM analysis revealed that hydrogen peroxide caused holes and slit formation in the fiber structure.
Źródło:
Polish Journal of Chemical Technology; 2014, 16, 3; 45-50
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of the reclamation method of spent moulding sands on the possibility of creating favourable conditions for gases flow in a mould
Autorzy:
Łucarz, M.
Drożyński, D.
Powiązania:
https://bibliotekanauki.pl/articles/352099.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
spent moulding sand
mechanical reclamation
thermal reclamation
organic binders
ignition loss
Opis:
The results of investigations concerning the influence of the applied sand matrix (fresh sand, reclaim) on the properties of moulding sands used for production of large dimensional castings (ingot moulds, ladles), are presented in the hereby paper. The performed investigations were aimed at determining the influence of various reclamation methods of spent moulding sands on the quality of the obtained reclaimed material. Moulding sands were prepared on the fresh quartz matrix as well as on sand matrices obtained after various reclamation methods. The selected moulding sand parameters were tested (strength, permeability, grindability, ignition losses, pH reactions). It can be stated, on the basis of the performed investigations, that the kind of the applied moulding sand matrix is of an essential meaning from the point of view of creating conditions minimising formation of large amounts of gases and their directional migration in a casting mould.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 1; 359-364
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pattern of seed losses and damage during soybean harvest with grain combine harvesters
Autorzy:
Kowalczuk, J.
Powiązania:
https://bibliotekanauki.pl/articles/24743.pdf
Data publikacji:
1999
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:
loss
mechanical harvest
Polska
grain
soybean
combine-harvester
harvester
harvest
agricultural mechanization
seed
Źródło:
International Agrophysics; 1999, 13, 1
0236-8722
Pojawia się w:
International Agrophysics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dynamic mechanical characterization of epoxy composite reinforced with areca nut husk fiber
Autorzy:
Muralidhar, N.
Kaliveeran, Vadivuchezhian
Arumugam, V.
Srinivasula Reddy, I.
Powiązania:
https://bibliotekanauki.pl/articles/139576.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
areca nut husk fiber
dynamic mechanical analysis
storage modulus
loss modulus
elastic modulus
damping factor
Opis:
Natural fiber polymer composites are gaining focus as low cost and light weight composite material due to the availability and ecofriendly nature of the natural fiber. Fiber composites are widely used in civil engineering, marine and aerospace industries where dynamic loads and environmental loads persist. Dynamic analysis of these composites under different loading and environmental conditions is essential before their usage. The present study focuses on the dynamic behavior of areca nut husk reinforced epoxy composites under different loading frequencies (5 Hz, 10 Hz and 15 Hz) and different temperatures (ranging from 28◦C to 120◦C). The effect of loading and temperature on storage modulus, loss modulus and glass transition temperature was analyzed. Increase in storage modulus is observed with increase in loading frequency. The storage modulus decreases with increase in temperature. The glass transition temperature of the composite is determined to be 105◦C. The elastic modulus calculated from the DMA data is compared with three point bending test
Źródło:
Archive of Mechanical Engineering; 2020, LXVII, 1; 57-72
0004-0738
Pojawia się w:
Archive of Mechanical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of soil conditions and mechanical characteristics of sugar beet roots on the value of force necessary for pulling them out
Autorzy:
Gorzelany, J.
Bzowska-Bakalarz, M.
Powiązania:
https://bibliotekanauki.pl/articles/26169.pdf
Data publikacji:
1999
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:
loss
harvesting machine
climate condition
soil condition
necessary
mechanical property
soil moisture
root
sugar-beet
Źródło:
International Agrophysics; 1999, 13, 4
0236-8722
Pojawia się w:
International Agrophysics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Development of Flux Structure for Processing of Aluminium Casting Production Wastes
Autorzy:
Turakhodjaev, N. D.
Tursunov, T. K.
Yakubov, L. E.
Abdurakhmanov, K. Z.
Turakhodjaeva, S. N.
Powiązania:
https://bibliotekanauki.pl/articles/382195.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
aluminum casting
flux
melting temperature
burn off loss
mechanical properties
impurities
odlewanie aluminium
topnik
temperatura topnienia
właściwości mechaniczne
zanieczyszczenia
Opis:
The objective of research is to define aluminium and its production wastes melting modes in electric unit while applying protective fluxes layer. This article cites the results of researches on development of flux structure for melting of aluminium production wastes. Melting unit diagram and results of research defining aluminium production wastes melting temperature regime are exemplified. Modes of metal charging, heating-up and melting of aluminium and its production wastes are exemplified for the electric unit with movable upper and immovable lower electrodes. The article describes the results of researches and recommendations that smelting chamber temperature to be maintained in the range of 1000-1100 °С, with melting zone temperature at 1400-1500 °С. It is recommended that charging of production wastes slag was carried after flux melt and reached 700-750 °С. Tables cite fluxes compositions that allow conducting aluminium melting process in various units. In the conclusion it is stated that application of a corresponding design of melting unit in aggregate with graphite electrodes and protective fluxes provides: - reduction of irretrievable metal burn-off losses; - savings on energy expenditures; - quality upgrade of liquid smelt due to decrease of oxide inclusions and occluded gas concentration.
Źródło:
Archives of Foundry Engineering; 2015, 15, 3 spec.; 91-94
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Role and Effectiveness of the MBP Installation in Poland Based on Selected Examples
Autorzy:
Wiśniewska, Marta
Lelicińska-Serafin, Krystyna
Powiązania:
https://bibliotekanauki.pl/articles/396201.pdf
Data publikacji:
2019
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
treatment of waste
biological treatment
mechanical treatment
municipal waste
mass loss
przetwarzanie odpadów
przetwarzanie biologiczne
przetwarzanie mechaniczne
odpady komunalne
utrata masy
Opis:
The paper presents examples of installations for the mechanical and biological treatment of municipal waste in Poland. Each of the presented installations is defined as a regional municipal waste treatment installation (RIPOK). Their technological solutions and work efficiency have been compared in this study. In addition, the loss of waste mass as a result of processes occurring in the biological part of individual installations was calculated in the research. The paper refers to the National Waste Management Plan (KPGO 2022) regarding the circular economy. As intended by the circular economy, MBP installations will be transformed into installations that will treat selectively collected municipal waste and become Regional Recycling Centers (RCR).
Źródło:
Civil and Environmental Engineering Reports; 2019, 29, 2; 1-12
2080-5187
2450-8594
Pojawia się w:
Civil and Environmental Engineering Reports
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dynamic Mechanical Properties of Artifcially Aged Double Base Rocket Propellant and the Possibilities for the Prediction of Their Service Lifetime
Autorzy:
Matečić-Mušanić, S.
Sućeska, M.
Powiązania:
https://bibliotekanauki.pl/articles/358886.pdf
Data publikacji:
2013
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
ageing
double base rocket propellants
dynamic mechanical analysis
glass transition temperature
lifetime prediction
loss modulus
softening temperature
storage modulus
tan δ
Opis:
The ageing of double base (DB) rocket propellants, as a consequence of the chemical reactions and physical processes that take place over time, has a signifcant effect on their relevant properties, such as chemical composition and mechanical and ballistic properties. The changes to relevant properties limit the safe and reliable service life of DB rocket propellants. Accordingly, numerous research efforts have been undertaken to fnd reliable methods to measure the changes caused by ageing in order to assess the quality of DB rocket propellants at a given moment of their lifetime, and to predict their remaining service lifetime. In this work we studied the dynamic mechanical properties of DB rocket propellant artifcially aged at temperatures of 80, 85 and 90 °C, in order to detect and quantify changes in the dynamic mechanical properties caused by ageing, and to investigate the possibilities for the prediction of service lifetime. Dynamic mechanical properties were studied using a dynamic mechanical analyser (DMA). The results obtained have shown that ageing causes signifcant changes in the storage modulus (E´), the loss modulus (E˝) and the tan δ curves’ shape and position. These changes are quantifed by following some characteristic points on the E´-T, E˝-T, and tan δ-T curves (e.g. glass transition temperatures; storage modulus, loss modulus and tan δ at characteristic temperatures, etc.). It has been found that the monitored parameters are temperature and time dependent, and that they can be shown to be functions of the so called ‘reduced time of artifcial ageing’. In addition, it has been found that, on the basis of known changes in viscoelastic properties as a function of time and ageing temperature, and the known kinetic parameters of the ageing process, it is possible to calculate (determine) the change in the properties at any ageing temperature provided that the mechanism of the ageing process does not change. Unfortunately, the use of kinetic parameters obtained by artifcial ageing at high temperatures (above 60 °C) for the prediction of the propellant lifetime will not give reliable results, because the mechanisms of ageing at 85 °C and 25 °C are not the same.
Źródło:
Central European Journal of Energetic Materials; 2013, 10, 2; 225-244
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Rock pore structure as main reason of rock deterioration
Autorzy:
Ondrášik, M.
Kopecký, M.
Powiązania:
https://bibliotekanauki.pl/articles/178163.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
mechanical weathering
rock deterioration
adsorbed water
adsorbed water freezing
rock porosity
freeze-thaw loss
proces zamrażania i rozmrażania
wietrzenie mechaniczne
adsorpcja wody
porowatość skał
Opis:
Crashed or dimensional rocks have been used as natural construction material, decoration stone or as material for artistic sculptures. Especially old historical towns not only in Slovakia have had experiences with use of stones for construction purposes for centuries. The whole buildings were made from dimensional stone, like sandstone, limestone or rhyolite. Pavements were made especially from basalt, andesite, rhyolite or granite. Also the most common modern construction material – concrete includes large amounts of crashed rock, especially limestone, dolostone and andesite. However, rock as any other material if exposed to exogenous processes starts to deteriorate. Especially mechanical weathering can be very intensive if rock with unsuitable rock properties is used. For long it had been believed that repeated freezing and thawing in relation to high absorption is the main reason of the rock deterioration. In Slovakia for many years the high water absorption was set as exclusion criterion for use of rocks and stones in building industry. Only after 1989 the absorption was accepted as merely informational rock property and not exclusion. The reason of the change was not the understanding of the relationship between the porosity and rock deterioration, but more or less good experiences with some high porous rocks used in constructions exposed to severe weather conditions and proving a lack of relationship between rock freeze-thaw resistivity and water absorption. Results of the recent worldwide research suggest that understanding a resistivity of rocks against deterioration is hidden not in the absorption but in the structure of rock pores in relation to thermodynamic properties of pore water and tensile strength of rocks and rock minerals. Also this article presents some results of research on rock deterioration and pore structure performed on 88 rock samples. The results divide the rocks tested into two groups – group N in which the pore water does not freeze even when the temperature decreases to –20 ºC, and the second group F in which the pore water freezes. It has been found that the rocks from group N contain critical portion of adsorbed water in pores which prevents freezing of the pore water. The presence of adsorbed water enables thermodynamic processes related to osmosis which are dominantly responsible for deterioration of rocks from group N. A high correlation (R = 0.81) between content of adsorbed water and freeze-thaw loss was proved and can be used as durability estimator of rocks from group N. The rock deterioration of group F is caused not only by osmosis, but also by some other processes and influences, such as hydraulic pressure, permeability, grain size, rock and mineral tensile strength, degree of saturation, etc., and the deterioration cannot be predicted yet without the freeze-thaw test. Since the contents of absorbed water and ratio between adsorbed and bulk water (of which the absorbed water consists) is controlled by the porosity and pore structure, it can be concluded that the deterioration of some rocks is strongly related to rock pore structure.
Źródło:
Studia Geotechnica et Mechanica; 2014, 36, 1; 79-88
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
State of Spent Molding Sands in the Mold Large-Size Cast
Autorzy:
Łucarz, M.
Powiązania:
https://bibliotekanauki.pl/articles/380064.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
spent moulding sand
organic binder
thermal destruction
ignition loss
mechanical reclamation
thermal reclamation
masa formierska
spoiwo organiczne
deformacja cieplna
strata prażenia
regeneracja mechaniczna
regeneracja termiczna
Opis:
The results of investigations of spent moulding sands taken from the mould at various distances from the surface of the produced casting, are presented in the paper. The casting mould was made with an application of the cooling system of the metal core in order to increase the cooling rate of the ladle casting. As temperature measurements in the mould indicated the heat flow from the metal did not create conditions for the complete burning of a moulding sand. The analysis was performed to find out changes of spent moulding sands caused by degradation and destruction processes of organic binders. Conditions occurring in the casting mould were discussed on the bases of testing: ignition losses, dusts contents, pH reactions and the surface morphology of the moulding sand samples. Factors limiting the effective mould degassing were pointed out. Operations, possible for realisation, which can limit the reasons of a periodical occurrence of increased amounts of casting defects due to changing gas evolution rates being the result of the technological process, were also indicated.
Źródło:
Archives of Foundry Engineering; 2016, 16, 4; 69-74
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Conditions of Thermal Reclamation Process Realization on a Sample of Spent Moulding Sand from an Aluminum Alloy Foundry Plant
Autorzy:
Łucarz, M.
Dereń, M.
Powiązania:
https://bibliotekanauki.pl/articles/382337.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
spent moulding sand
organic binders
thermal destruction
ignition loss
mechanical reclamation
thermal reclamation
zużyte masy formierskie
spoiwa organiczne
zniszczenie termiczne
straty prażenia
regeneracja mechaniczna
regeneracja termiczna
Opis:
The results of investigations of thermal reclamation of spent moulding sands originating from an aluminum alloy foundry plant are presented in this paper. Spent sands were crushed by using two methods. Mechanical fragmentation of spent sand chunks was realized in the vibratory reclaimer REGMAS. The crushing process in the mechanical device was performed either with or without additional crushing-grinding elements. The reclaimed material obtained in this way was subjected to thermal reclamations at two different temperatures. It was found that a significant binder gathering on grain surfaces favors its spontaneous burning, even in the case when a temperature lower than required for the efficient thermal reclamation of furan binders is applied in the thermal reclaimer. The burning process, initiated by gas burners in the reclaimer chamber, generates favorable conditions for self-burning (at a determined amount of organic binders on grain surfaces). This process is spontaneously sustained and decreases the demand for gas. However, due to the significant amount of binder, this process is longer than in the case of reclaiming moulding sand prepared with fresh components.
Źródło:
Archives of Foundry Engineering; 2017, 17, 2; 197-201
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-15 z 15

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