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1
Content available Study on condition prediction and influencing factors of manganese carbonate recovery by high gradient pulse magnetic separation
Wang Zhenggang, Nie Guanghua, Tang Yun, Piao Haishan, Chen Jian
Physicochemical Problems of Mineral Processing
|
2023
|
Vol. 59, iss. 3
art. no. 168668
EN
Manganese carbonate ore belongs to weakly magnetic minerals, and its co-associated minerals are mainly non-magnetic minerals, which can be separated from gangue minerals at high magnetic field intensity. However, manganese grade and recovery of magnetic separation concentrate of manganese carbonate ore are low in actual production. Therefore, the influences of manganese carbonate particle size, magnetic field intensity, volume susceptibility, pulse stroke, pH, and other factors were studied. The optimal test conditions for manganese carbonate ore recovery by high-gradient magnetic separation were predicted through the calculation results. The results show that the particle radius of manganese carbonate is 0.020 mm, the pulse impulse time is 200 r/min, and the magnetic field intensity is 0.9 T. The optimum condition test was carried out with Qianbei manganese carbonate ore as the material. The test results show that the optimum conditions are the particle radius of 0.074-0.019 mm, pulse impulse time of 200 r/min, and magnetic field intensity of 1.2 T. The reason for the deviation is that the actual ore has a fine distribution particle size, many associative bodies, complex composition, and serious agglomeration, resulting in variable particle volume susceptibility. The capture yield increases with the increase of magnetic field intensity and volume susceptibility but decreases with the increase of pulse. The lower the surface potential of manganese carbonate, the higher the recovery of manganese carbonate. The grade of manganese concentrate was 19.06% and the recovery was 76.85%. Mixed manganese concentrate with a grade of 18.04% and recovery of 87.14% was obtained by adding drugs and changing the grinding method.
2
Content available remote Wpływ stosowania różnych torów wysokich częstotliwości na wartość wyniku pomiaru amplitudy generowanego impulsu HPM
Przesmycki Rafał, Bugaj Marek
Przegląd Elektrotechniczny
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2021
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R. 97, nr 10
91--95
PL
Artykuł przedstawia wybrane zagadnienia z obszaru pomiaru parametrów impulsowego pola elektromagnetycznego. Jego celem było przeanalizowanie wpływu stosowania różnych torów wysokich częstotliwości na wartość pomiaru amplitudy impulsu HPM (High Power Microwave) generowanego na stanowisku pomiarowym do badania urządzeń informatycznych na oddziaływanie broni wiązkowej bazującej na impulsach HPM.
EN
The paper presents some issues concerning measurements of the pulsed electromagnetic field. Its purpose was to analyze the impact of the use of various high-frequency cable on the measurement of amplitude value the HPM pulse (High Power Microwave) generated at the laboratory stand for testing IT devices on the impact of beam weapons based on HPM pulses.
3
Content available remote Oscillations in systems of impulsive nonlinear partial differential equations with distributed deviating arguments
Bortolan M. C., Chatzarakis G. E., Kalaimani T., Raja T., Sadhasivam V.
Fasciculi Mathematici
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2019
|
nr 62
13--33
EN
In this paper, we consider systems of impulsive nonlinear neutral delay partial differential equations with distributed deviating arguments and sufficient conditions for the oscillation of the system under the Dirichlet boundary condition. The main results are illustrated by one example.
4
Content available remote On General Solution for Fractional Differential Equations with Not Instantaneous Impulses
Zhang X., Zhang X., Cao H.
Fundamenta Informaticae
|
2017
|
Vol. 151, nr 1/4
355--369
EN
In this paper we mainly study a kind of fractional differential equations with not instantaneous impulses, and find the equivalent equations of the impulsive system. The obtained result discovers that there exist general solution for the impulsive system. Next, an example is given to illustrate the obtained result.
5
Content available Studies on FOX-7 Based Melt Cast High Explosive Formulations
Mishra V. S., Vadali S. R., Garg R. K., Joshi V. S., Wasnik R. D., Asthana S.
Central European Journal of Energetic Materials
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2013
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Vol. 10, no. 4
569--580
EN
The key driving force in modern explosive research is the development of low vulnerable high explosive (LOVEX) compositions for future applications in insensitive munitions (IMs). The increasing demand for LOVEX has led to exhaustive studies on low vulnerable explosives as a replacement for conventional cyclo-1,3,5-trimethylene-2,4,6-trinitramine (RDX) in 2,4,6-trinitrotoluene (TNT) melt cast high explosive formulations. In the present study, 1,1-diamino-2,2dinitroethene (FOX-7) has been evaluated as a possible RDX replacement in TNT based, non-aluminized as well as aluminized, melt cast formulation. FOX-7 based melt cast formulations were characterized for their sensitivity to mechanical/shock stimuli, velocity of detonation (VOD), blast parameters and thermal decomposition behavior. These characteristics are compared with the corresponding RDX based compositions as reference standard. The studies show that with little sacrifice on performance parameters, FOX-7 based, non-aluminized and aluminized, melt cast formulations are found to be less vulnerable, compared with the corresponding RDX based formulations.
6
Content available Effect of Tungsten on Aluminized Melt Cast High Explosive Formulations
Mishra V. S., Bhagat. A. L., Vadali S. R., Singh V. K., Wasnik R. D., Asthana S.
Central European Journal of Energetic Materials
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2012
|
Vol. 9, nr 2
147-154
EN
Aluminized 2,4,6-trinitrotoluene (TNT) based, melt-cast, high explosive compositions are widely used in warheads. These compositions offer a blast effect over a larger period due to the secondary combustion of aluminum. During recent times tungsten based explosives have been reported for lethality at close range to avoid collateral damage in low intensity conflicts (LIC) and find application in shaped charges to enhance their penetration capability. This paper reports findings on tungsten-based, melt-cast, explosive formulations. The compositions were prepared by substituting aluminum with tungsten in the reference aluminized, high explosive formulation. The compositions were characterized for their sensitivity to mechanical/shock stimuli, velocity of detonation (VOD) and blast performance. The study reveals that the impact sensitivity remains comparable on incorporating 10% tungsten at the cost of aluminum whereas an increase in tungsten content to 20% leads to an increase in impact sensitivity. However friction sensitivity and shock sensitivity remained more or less unchanged. The velocity of detonation (VOD) of tungsten-loaded, aluminized formulations is found to be comparable to the standard aluminized formulation. The peak over pressure of tungsten-based formulations is lower than the reference, aluminized composition at close range but is almost unchanged at long range. The impulse of tungsten-based formulations is also lower than the reference, aluminized composition. The reduction in impulse at close range is substantial on replacing 10% aluminum with inert tungsten.
7
Content available Kształtowanie elektrochemiczne łopatki sekwencją procesów ECM-PECM
Kozak J.
Inżynieria Maszyn
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2011
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R. 16, z. 4
68-74
PL
W pracy przedstawiono kształtowanie elektrochemiczne pióra łopatki lotniczych silników turbinowych w dwu kolejnych zabiegach, a mianowicie obróbki prądem ciągłym ECM i prądem impulsowym PECM. Omówiono zadania cząstkowe niezbędne w projektowaniu i optymalizacji technologii elektrochemicznej Wykazano, że dokładność wymiarową ECM/PECM można poprawić utrzymując małą szczelinę pomiędzy elektrodami.
EN
Electrochemical machining using continuous and pulse current (ECM, PECM) provides an economical and effective method for machining high strength, heat-resistant materials into complex shapes such as airfoils of titanium alloys. The dimensional accuracy of ECM/PECM can be improved if a small interelectrode gap is maintained. This paper presents the manufacturing of airfoils by sequences both treatments ECM and PECM.
8
Content available Badanie wpływu sygnału wymuszenia energetycznego na wynik analizy częstotliwościowej w technikach termografii aktywnej
Gralewicz G., Więcek B.
Pomiary Automatyka Kontrola
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2009
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R. 55, nr 11
902-905
PL
Przedstawione w pracy wyniki dotyczą badania wpływu rodzaju sygnału wymuszenia energetycznego na wynik analizy częstotliwościowej sekwencji obrazów termograficznych oraz zestawienia wyników analiz Fouriera i falkowej dla materiałów jednorodnych termicznie. Na podstawie przeprowadzonych doświadczeń popartych modelowaniem komputerowym określono wpływ sygnału wymuszenia energetycznego periodycznego i impulsowego na wynik analizy częstotliwościowej.
EN
Results of the excitation energy impact on frequency analysis for active thermography techniques are presented. Active thermography is a non-destructive evaluation method (NDE) in which tested items are excited with heat excitation, while infrared camera measures the changes of temperature distribution in time. Heat spreads in solid materials through diffusion which is strongly dependent on the thermal qualities of the tested material. The investigations included computer simulation and experimental tests. The analysis results of different excitation (frequency and time) for testing thermally conductive and isolative materials while using impulse and periodic energy signals are presented. The comparison between the Fourier and wavelets analysis for thermally homogeneous materials is discussed. The authors defined a parameter phase difference K? for signature defect in materials whose maximum value indicates the frequency of heat excitation. For isolative materials its value is much larger (the larger the thickness of the material, the greater the value of phase angle), while for conductive ones it is smaller, hence it is difficult to locate a defect in the material. The results of the excitation energy impact on the frequency analysis showed that periodic energy is more advantageous for isolative materials, whereas impulse energy is more useful for conductive materials.
9
Selected problems of the classic theory of impact
Szcześniak W., Ataman M.
Logistyka
|
2009
|
nr 6
CD-CD
EN
Theoretical bases for the theory of impact are discussed in the paper. Three theories used for analyses of the impact problems are presented: classic theory, deformation theory and wave theory. The problem of the rigid hoop's collision with the rigid threshold is solved by means of the classic theory of the impact. Solutions for rigid roller and rigid sphere colliding with the same threshold are presented in the paper also.
PL
W pracy przedstawiono teoretyczne podstawy teorii uderzenia. Omówiono trzy teorie stosowane przy rozwiązywaniu zagadnień związanych z uderzeniem: teorię klasyczną, teorię deformacyjną oraz teorię falową. Stosując klasyczną teorię uderzenia rozwiązano zadanie zderzenia sztywnej obręczy ze sztywną ścianą. Podano również rozwiązania w przypadku zderzenia krążka i kuli z taką samą przeszkodą.
10
Particular cases of problems of the classic theory of impact
Szcześniak W., Ataman M.
Logistyka
|
2009
|
nr 6
CD-CD
EN
In the paper some particular cases of rigid bodies' collision are presented: the hoop's collision with vertical wall, the hoop’s collision with oblique wall and the roller's collision with threshold. The problems are solved according to the classic theory of impact. Solutions are obtained from equations derived by authors in the paper [1]. The wave phenomenon is utilized and the sequence of impacts is assumed. Three cases of the roller's collision with the threshold are analyzed in the paper: rolling without slipping, rolling with slipping at the instant of collision and slipping (Coulomb's coefficient ).
PL
W pracy przedstawiono wybrane zadania dotyczące zderzenia ciał sztywnych: zderzenie obręczy z pionową ścianą, zderzenie obręczy z ukośną ścianą oraz uderzenie krążka w próg. Zagadnienia rozwiązano na podstawie klasycznej teorii uderzenia. Rozwiązania otrzymano korzystając z równań uzyskanych przez autorów w pracy [1]. Rozwiązując zadania wykorzystano zjawisko falowe oraz założono pewną sekwencję uderzeń. W zadaniu dotyczącym uderzenia w próg toczącego się po poziomej podłodze krążka przeanalizowano trzy przypadki: toczenie bez poślizgu, toczenie z poślizgiem podczas uderzenia oraz przypadek przy założeniu kompletnego braku tarcia poślizgowego pomiędzy krążkiem a progiem.
11
Content available remote Low velocity impact of composite crop straw panels
Abou-Taleb H., Sakr A.
Autex Research Journal
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2009
|
Vol. 9, no. 1
20--28
EN
The shock behaviour of crop straw reinforced composites with unsaturated polyester epoxy was studied. In this research an attempt has been made to design and manufacture protective composite vests for soldiers. The low velocity impact loading was generated by a drop weight impact machine with drop heights varying from 100 to 200 mm. The drop mass used in these experiments was 15 kg. The shock-absorbing capacity of the vests was found to be strongly affected by straw type, straw weight percentage per unit volume of composite panel (the permanent composite volume of the panel is equal to 434.2 cm3), and broken short rounded straight steel wire to straw weight ratio. This research concerns the evaluation of all the low velocity drop weight test parameters such as peak dynamic force, duration time, and impulse due to free falling of drop mass at different impact energies: 1.5, 2.25, and 3 J. In addition, indentation parameters such as contact force and absorbed energy could be evaluated. Mathematical models describing these parameters are presented in a form that can be easily predicted. The predicted shock-absorbing capacity shows good agreement with the experimental results. In addition, the optimum tailoring variables affecting the shock-absorbing performance of the composite vest system could be determined.
12
Content available remote Druhstadijnoe izmel'cenie kak naibolee ekonomiceski vygodnyj variant organizacii processa sverhtonkogo pomola tvedryh materialov
Voroncov N., Zuravlev V., Blinicev V.
Czasopismo Techniczne. Mechanika
|
2008
|
R. 105, z. 2-M
411-414
EN
In this paper is described a scheme of ultrafine grinding, wich present is most economically expedient variant in case of hard materials and high surface energy materials grinding.
13
Content available remote Asymptotic behavior of solutions of impulsive differential equations with positive and negative coefficients
Wei G., Shen J.
Fasciculi Mathematici
|
2005
|
Nr 36
109-119
EN
This paper is concerned with the impulsive delay differential equations with positive and negative coefficients Sufficient conditions are obtained for every solution of the above equation tends to a constant as t —> &infin. KEY WORDS: asymptotic behavior, Liapunov functional, delay differential equation, impulse, coefficients.
14
Content available remote On stability in impulsive dynamical systems
Ciesielski K.
Bulletin of the Polish Academy of Sciences. Mathematics
|
2004
|
Vol. 52, nr 1
81-91
EN
Several results on stability in impulsive dynamical systems are proved. The first main result gives equivalent conditions for stability of a compact set. In particular, a generalization of Ura's theorem to the case of impulsive systems is shown. The second main theorem says that under some additional assumptions every component of a stable set is stable. Also, several examples indicating possible complicated phenomena in impulsive systems are presented.
15
Content available remote On semicontinuity in impulsive dynamical systems
Ciesielski K.
Bulletin of the Polish Academy of Sciences. Mathematics
|
2004
|
Vol. 52, nr 1
71-80
EN
In the important paper on impulsive systems [Kl] several notions are introduced and several properties of these systems are shown. In particular, the function [phi] which describes "the time of reaching impulse points" is considered; this function has many important applications. In [Kl] the continuity of this function is investigated. However, contrary to the theorem stated there, the function [phi] need not be continuous under the assumptions given in the theorem. Suitable examples are shown in this paper. We characterize the function [phi] from the point of view of its semicontinuity. Also, we show the analogous properties for impulsive systems given by semidynamical systems. In the last section we investigate the continuity properties of the escape time function in impulsive systems.
16
Content available remote Problemy poprawy jakości jednoznacznego pomiaru predkości radialnej w radarze o małej częstotliwości powtarzania
Brenner T. W., Modrzewski A. P., Pietrasiński J. F., Rapacki T.
Biuletyn Wojskowej Akademii Technicznej
|
2002
|
Vol. 51, nr 7
87-105
PL
Artykuł zawiera opracowanie właściwego dobierania częstotliwości powtarzania impulsów w radarze małej częstotliwości powtarzania stosującym przetwarzanie typu MTD [1]. Dobór ten w myśl przyjętego kryterium powinien zapewniać jak najlepszą jakość jednoznacznego pomiaru prędkości radialnej. Dlatego zasadniczym celem rozważań było opracowanie narzędzi, pozwalajacych na pokonanie niedoskonałości metody doboru częstotliwości powtarzania impulsów opisanej w [1]. W myśl przyjętego kryterium opracowano takie narzędzie oparte na algorytmach genetycznych. Wykonano niezbedne porównawcze badania symulacyjne, które wykazały istotną poprawę wskaźników jakości algorytmów jednoznacznego określania predkości radialnej wykorzystujących częstotliwości powtarzania określone algorytmem genetycznym.
EN
A matching of frequency repeating of pulses in MTD radar of low frequency repeating is studied. The matching should assure the best quality of measurement of unique radial velocity. The tool enabling elimination of imperfection in the matching of pulse frequency repeating was elaborated [1]. The tool operates on the genetic algorithm basis. The carried out comparative simulation studies showed the significant improvement in the quality indices of algorithms for determination of unique radial velocity using the frequency repeating determined by a genetic algorithm. The elimination of the influence of used frequency diversity [1] on the quality of unique radial velocity determination was also discussed. Two methods are proposed to solve this problem. The first one was connected with modification of genetic algorithm for frequency repeating matching and the second on with modification of the radial volecity measurement algorithm. The study results showed the limited application of the two modifications.
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