Wyniki wyszukiwania - BazTech

1

Postawić kwantową teorię pola z głowy na nogi. Część 3

Chankowski Piotr

Postępy Fizyki

|

2024

|

T. 75, z. 1

2--17

PL

Wbrew wrażeniu jakie można odnieść z większości standardowych podręczników, równania falowe Diraca, Kleina-Gordona i inne nie są podstawą kwantowej teorii pola. W niniejszym artykule staram się pokazać, jak powinna być ona poprawnie formułowana i omawiam pewne jej aspekty, które na ogół nie są przedstawiane właściwie. Celem artykułu jest spowodowanie zmiany w nauczaniu kwantowej teorii pola. Tekst został podzielony na trzy części. W niniejszej części 3 (i ostatniej) omawiam przepis LSZ pozwalający wyznaczać elementy macierzy S i inne wielkości fizyczne bez czynienia zwykłych, bardzo restrykcyjnych założeń oraz zalety i słabości formułowania kwantowej teorii pola za pomocą całek po trajektoriach.

EN

Despite the impression that can be gained from most of the standard textbooks, Dirac, Klein-Gordon and other wave equations do not constitute the basis of quantum field theory. In this article I attempt to show how it should be formulated properly and discuss some of its aspects which usually are presented unsatisfactorily. The aim of the text is to cause the change in the way quantum field theory is taught. The text is split into three parts. In this part 3 (the last one) I discuss the LSZ prescription which allows to extract S-matrix elements without making the usual, very restrictive assumptions and advantages and weak sides of formulating quantum field theory with the help of path integrals.

2

Improving voltage stability in subtransmission through PV curves and critical voltage balance for photovoltaic compensation

Santillán Hólger Jorge, Barzola Roosevelt

Diagnostyka

|

2024

|

Vol. 25, No. 1

art. no. 2024111

EN

The constant increase in energy demand and the need to reduce the carbon footprint on the environment has put countries in a race against time, looking for alternative resources or ways to supply this need. One of the main resources is solar radiation, which can be used to generate energy, initially on a small scale, but in recent years has been directed towards supplying large cities. The economic, political, and social investment must respond to planning and expansion criteria in order to generate feasible proposals. Through simulation of a real electrical system, the voltage instability was determined, which was corrected at software level by entering a photovoltaic solar plant, being this dimensioned from the PV curve obtained. Finally, the optimal location for the development of a solar photovoltaic plant among four possible scenarios was obtained through the application of an optimization algorithm. This approach was converted into an alternative applicable to different geographical locations.

3

Postawić kwantową teorię pola z głowy na nogi. Część I

Chankowski Piotr

Postępy Fizyki

|

2023

|

T. 74, z. 3

5--14

PL

Wbrew wrażeniu jakie można odnieść z lektury większości standardowych podręczników, równania falowe Diraca, Kleina-Gordona i inne nie są podstawą relatywistycznej kwantowej teorii pola. W niniejszym artykule staram się pokazać, jak powinna być ona poprawnie formułowana i omawiam pewne jej aspekty, które na ogół nie są przedstawiane właściwie. Moim celem jest spowodowanie zmiany w nauczaniu kwantowej teorii pola. Tekst został podzielony na trzy części. W pierwszej przypominam krótko historyczny rozwój kwantowej teorii pola i omawiam jej sformułowanie jako kwantowej teorii oddziałujących cząstek (relatywistycznych lub nierelatywistycznych).

EN

Despite the impression that can be gained from most of the standard textbooks, Dirac, Klein-Gordon and other wave equations do not constitute the basis of relativistic quantum field theory. In this article I attempt to show how it should be formulated properly and discuss some of its aspects which usually are presented unsatisfactorily. My aim is to cause the change in the way quantum field theory is taught. The text is split into three parts. In the first one I briefly recall the quantum field theory historical development and present its formulation as a quantum theory of interacting particles (relativistic or nonrelativistic).

4

Organosolv lignin particles as an ecological reagent in the Kupfershiefer copper ore flotation

Witecki Kajetan, Szkurat Monika, Hruzova Katerina

Physicochemical Problems of Mineral Processing

|

2023

|

Vol. 59, iss. 6

art. no. 174363

EN

Mineral separation relies heavily on the process of flotation. This study explored the feasibility of using organosolv lignin nanoparticles and microparticles (OLP) as a greener alternative to xanthates in the flotation process for mineral separation. Xanthates are widely used but pose environmental and health risks. The efficiency of OLP as collectors was compared to collectorless flotation, resulting in approximately 50% copper recovery, indicating that OLP may not be a suitable replacement for xanthates. Further tests were conducted using a mixture of xanthates and OLP (birch nano and spruce micro) with varying substitution levels (20%, 30%, and 40%). The results demonstrated that increasing the dosage of OLP led to a decrease in flotation efficiency for copper. TOC analysis of the products revealed that high dosages (160 g/t) of birch nano and spruce micro as sole collectors showed beneficiation and selective recovery against copper. While OLPs did not prove effective as collectors, the study highlights their potential as substitutes for maltodextrin in selective flotation of the final concentrate. Two out of four tested OLPs were recommended for pilot scale testing.

5

Understanding technical cleanliness: importance, assessment, maintenance

Faber Joanna, Brodzik Krzysztof, Nycz Marta

Combustion Engines

|

2021

|

R. 60, nr 3

41--50

EN

Development of the automotive industry, including so-called dowsizing and rightsizing, entails the need to ensure, and hence to verify, the stringent cleanliness levels of an increasing number of car components. The assurance of proper cleanliness level requires knowledge of the entire production process and precise information on the contaminants that will allow to identify their sources. Obtaining reliable cleanliness information requires establishing of many different factors, i. a. selection of proper contamination extraction and collection technique, proper parameters of extraction, validation of extraction procedure, methods of particles analysis. Analytical techniques which are implemented include gravimetric, optical microscopy and advanced techniques like scanning electron microscopy. This work present’s actual state of knowledge regarding technical cleanliness analysis of components. Important aspects of QA&QC in technical cleanliness assessment are also discussed.

6

Effect of flow structure and colloidal forces on aggregation rate of small solid particles suspended in aqueous solutions

Tyl Grzegorz, Kondracki Juliusz, Jasińska Magdalena

Chemical and Process Engineering

|

2021

|

Vol. 42, nr 4

369-–389

EN

In this paper aggregation of small solid particles in the perikinetic and orthokinetic regimes is considered. An aggregation kernel for colloidal particles is determined by solving the convection-diffusion equation for the pair probability function of the solid particles subject to simple shear and extensional flow patterns and DLVO potential field. Using the solution of the full model the applicability regions of simplified collision kernels from the literature are recognized and verified for a wide range of Péclet numbers. In the stable colloidal systems the assumption which considers only the flow pattern in a certain boundary layer around central particle results in a reasonable accuracy of the particle collision rate. However, when the influence of convective motion becomes more significant one should take into account the full flow field in a more rigorous manner and solve the convection-diffusion equation directly. Finally, the influence of flow pattern and process parameters on aggregation rate is discussed.

7

The fatigue crack behavior of 7N01-T6 aluminum alloy in different particle environments

Chen Y. Q., Tang Z. H., Pan S. P., Liu W. H., Song Y. F., Zhu B. W., Liu Y., Wen Z. L.

Archives of Civil and Mechanical Engineering

|

2020

|

Vol. 20, no. 4

468--483

EN

An experimental method of evaluating the fatigue behavior of alloys in different particle environments was designed, and the effects of four kinds of particles (i.e., graphite, CaO, Al2O3, and MnO2) on the crack propagating behavior of 7N01-T6 behaviour alloys were investigated. The results show that the particles deposited on the crack surface exert significant influence on the fatigue crack propagation behavior thereof. This influence strongly depends on the elastic moduli of the particles (Ep). As Ep is less than that of aluminium alloy (EAl), the particle accelerates the fatigue-crack-growth rate (FCGR) in the alloys due to the lubrication of the particles on the mating fracture surfaces. When the difference between Ep and EAl is small, the particle effect on the FCGRs of the alloys is small due to the counteraction between the decrease in friction and the promotion on the crack closure of mating fracture surfaces. When Ep is greater than EAl, the particles slow down the FCGRs of the alloys on account of significant crack closure effect. As Ep is much greater than EAl, the particles increase the FCGRs because of the increasing stress concentration at the crack tip.

8

Ocena możliwości wytworzenia i uzyskania nowych efektów wizualnych kompozytów na osnowie poliacetalu (POM) modyfikowanych włóknami i cząstkami naturalnymi

Bazan P., Kuciel S.

Przetwórstwo Tworzyw

|

2018

|

T. 24, Nr 3 (183)

7--14

PL

W artykule dokonano oceny możliwości wytworzenia i uzyskania nowych efektów wizualnych kompozytów na osnowie poliacetalu (POM) modyfikowanych włóknami i cząstkami naturalnymi. Wytworzono trzy kompozycje na osnowie poliacetalu z 12.5% udziałem masowym mączki drzewnej, kawy mielonej oraz pociętvch: banknotów 200 złotowych, jako kompatybilizator zastosowano Aldrich Tris (2-metoxyetoxy)(vinyl). Wykonano badania podstawowych właściwości fizyko-mechanicznych w szerokim zakresie temperatur oraz zdjęcia makro i mikroskopowe za pomocą mikroskopu optycznego i elektronowego dla zobrazowania charakteru zastosowanych napełniaczy. Kompozyty tego typu przeznaczone są na elementy sprężyste o wysokich wymaganiach odnośnie trwałości, ale też estetyki w przemyśle dekoracyjnym.

EN

In this paper the possibility of producing and obtaining new visual effects of composites based on polyacetal (POM), modified by natural fibers and particles was evaluated. Three compositions based on polyacetal matrix with 12.5wt% content of wood flour, ground coffee and cut 200 PLN banknotes were prepared. As a compatybilizer Aldrich Tris(2-metoxyetoxy) (vinyl) was used. The basic physical and mechanical properties were estimated. The tests were conducted at wide temperature range. In order to illustrate the nature of used fillers macro and microscopic images were taken using optical and electron microscopy. Composites of this type are designed for elastic elements with high demands on durability, as well as aesthetics in the decorative industry.

9

Influence of load and reinforcement content on selected tribological properties of Al/SiC/Gr hybrid composites

Veličković S., Miladinović S., Stojanović B., Nikolić R. R., Hadzima B., Arsić D.

Production Engineering Archives

|

2018

|

Vol. 18

18--23

EN

Hybrid materials with the metal matrix are important engineering materials due to their outstanding mechanical and tribological properties. Here are presented selected tribological properties of the hybrid composites with the matrix made of aluminum alloy and reinforced by the silicon carbide and graphite particles. The tribological characteristics of such materials are superior to characteristics of the matrix – the aluminum alloy, as well as to characteristics of the classical metal-matrix composites with a single reinforcing material. Those characteristics depend on the volume fractions of the reinforcing components, sizes of the reinforcing particles, as well as on the fabrication process of the hybrid composites. The considered tribological characteristics are the friction coefficient and the wear rate as functions of the load levels and the volume fractions of the graphite and the SiC particles. The wear rate increases with increase of the load and the Gr particles content and with reduction of the SiC particles content. The friction coefficient increases with the load, as well as with the SiC particles content increase.

10

Inherent optical properties and particulate matter distribution in summer season in waters of Hornsund and Kongsfjordenen, Spitsbergen

Sagan S., Darecki M.

Oceanologia

|

2018

|

No. 60 (1)

65--75

EN

Two Spitsbergen fjords, Hornsund and Kongsfjorden, are known for being under different hydrological regimes. The first is cold, separated from warm Atlantic water by East Spitsbergen Current, while Kongsfjorden is frequently penetrated by relatively warm Atlantic water. On the other hand, both are under strong influence of water discharge from glaciers and land freshwater input. During the period of observation in both fjords a dominant water mass was Surface Water, which originates mainly from glacial melt. The presence of suspended matter introduced with melt water in Surface Water is reflected by highest values of light attenuation and absorption coefficients recorded in areas close to glacier both in Hornsund and Kongsfjorden. In Hornsund the maximum light attenuation coefficient cpg(555) was 5.817 m−1 and coefficient of light absorption by particles ap(676) = 0.10 m−1. In Kongsfjorden the corresponding values were 26.5 m−1and 0.223 m−1. In Kongsfjorden suspended matter of the size class 20-200 μm dominated over fractions smaller than 20 μm while in Hornsund dominating size fraction was 2-20 μm. The results provide an evidence of considerable range of variability of the optical properties mainly due to glacial and riverine runoff. The scale of variability of particulate matter in Kongsfjorden is bigger than in Hornsund. Most of the variability in Hornsund can be attributed to glaciers discharge and a presence of particles of mineral origin, while in Kongsfjorden the organic and mineral particles contribute almost equally to defining the optical properties of water.

11

Monitoring cząstek i jego znaczenie w prawidłowym funkcjonowaniu pomieszczeń clean room

Sitek P.

Laboratorium Medyczne

|

2018

|

nr 2

50--52

PL

Istotą klasyfikacji pomieszczeń czystych jest prawidłowe określenie zawartości cząstek w powietrzu – czyli czystości pyłowej powietrza. Zgodnie z wytycznymi normy ISO 14644 wyróżniamy 9 klas czystości pomieszczeń. Utrzymanie klasy czystości wymaga regularnego przeprowadzania monitoringu cząstek, a także wprowadzenia materiałów, wyposażenia i urządzeń mających właściwości niepylące.

EN

The essence of clean room classification is the correct determination of the particle contamination of the air – that is, the dust cleanness of the air. According to the guidelines of ISO 14644, we distinguish 9 cleanliness classes of rooms. Maintaining the purity class requires the regular monitoring of particles as well as the introduction of materials, equipment and devices of non-dusting properties.

12

Evaluation of the impact of oil presence in the aviation fuel on particle size distribution

Jasiński R., Pielecha J.

Zeszyty Naukowe. Transport / Politechnika Śląska

|

2017

|

z. 94

57--64

EN

Emissions from aircraft engines represent a highly complex and important issue, which is related to the risk to human health. Particles emitted in urban areas and in the vicinity of airports affect air quality and have a particularly negative impact on airport workers. The development of measurement techniques and the methodology for evaluating exhaust emissions have allowed for the elaboration of appropriate procedures for the certification of aircraft and the enhancement of existing standards. Particulate matter emissions depend, among other things, on the composition of the fuel used and its additives. Some aircraft engine designs require a fuel additive in the form of oil, which ensures the proper operation of the fuel supply system. This article presents the results of studies conducted on jet engines powered by clean aviation fuel and fuel with the addition of oil. The aim of the study was to evaluate the effect of the addition of oil on the size distribution and concentration of emitted particles. It was found that, for small values of thrust, oil additive increases the concentration of particles. With an increase in the thrust force, the reduction of particles concentration was recorded in the case of the engine powered by fuel with oil additive. There was no significant effect of oil additive on the size distribution of emitted particles.

13

Particle effect system for the needs of a modern video game using the GPU

Zeler W., Rohleder P.

Machine Graphics and Vision

|

2016

|

Vol. 25, No. 1/4

35--44

EN

A new system of creation and management of particle effects created for the needs of the future productions of Techland Co. Ltd. is presented. By a proper organisation of memory buffers it provides for maximum data density in the memory. This makes it possible to simplify the calculations and to use a smaller number of threads and less memory readings.

14

Hydrodynamika przepływu cząstek w aparacie z cyrkulującym złożem rzadkim

Ludwig W.

Inżynieria i Aparatura Chemiczna

|

2016

|

Nr 5

189--190

PL

W pracy zaprezentowano wyniki badań hydrodynamiki przepływu cząstek w oryginalnym aparacie będącym rozwinięciem rozwiązania zastosowanego przez Wurstera, który służy do suchego powlekania materiałów farmaceutycznych. Wykonano pomiary prędkości przepływu cząstek oraz ich ułamka objętościowego w różnych strefach urządzenia. Udowodniono, że zastosowana w dolnej części aparatu strumienica spowodowała znaczący wzrost prędkości przepływu cząstek, co przyczyniło się do znaczącego skrócenia procesu powlekania.

EN

The paper presents results of the studies on the hydrodynamics of particles flow in the original apparatus being a development of classical Wurster design and used for dry coating and encapsulation of pharmaceutical materials. Measurements of particles velocity and their volume fraction in different zones of the device were carried out. It was proved that the injector applied in the lower part of apparatus caused a significant increase in particles velocity what contributes to a considerable reduction of coating process time.

15

Emisja wybranych, toksycznych składników spalin przez różne środki transportu

Witaszek M., Witaszek K.

Zeszyty Naukowe. Transport / Politechnika Śląska

|

2015

|

z. 87

105--112

PL

W niniejszym artykule zestawiono emisję: tlenków azotu, węglowodorów, tlenku węgla i cząstek stałych dla różnych środków transportu. W zestawieniu uwzględniono transport: drogowy, kolejowy i lotniczy. Do analizy użyto danych dostępnych w literaturze. Przedstawiono je oddzielnie dla każdego z ww. rodzajów transportu. W celu ułatwienia porównania środków pasażerskiego i towarowego transportu drogowego zestawiono dane dotyczące emisji przypadającej na jednostkę drogi. Ponadto, zaprezentowano dane dotyczące emisji na jednostkę pracy przewozowej, która umożliwia porównanie transportu drogowego z kolejowym i lotniczym. Porównanie to umożliwiło określenie różnic występujących pomiędzy poszczególnymi rodzajami transportu. W transporcie lotniczym zaobserwowano istotny wpływ odległości pokonywanej w trakcie lotu na emisję. W przypadku lotów w kierunku zbliżonym do równoleżnikowego istotne jest także, czy odbywa się on zgodnie z ruchem Ziemi czy przeciwnie do niego.

EN

This article presents data that concerns emission of nitrogen oxides, hydrocarbons, carbon monoxide and particles by different transport means. The road, rail and air transport were taken into account. The data published in references were analysed. To compare freight and passenger road transport emission expressed in grams per kilometre was presented. The emission in mg per passenger-kilometre enabled comparison of cars trains and planes in terms of air pollutant discharge. The data comparison revealed significant differences between transport modes. For aviation significant influence of flight distance on emission was observed. For flights running evenly with a parallel of latitude also the direction – according or opposite to the Earth rotation is significant.

16

Microwave-assisted synthesis, characterization and photoluminescence of shuttle-like BaMoO4 microstructure

Phuruangrat A., Kuntalue B., Thongtem T., Thongtem S.

Materials Science Poland

|

2015

|

Vol. 33, No. 3

537--540

EN

Shuttle-like BaMoO4 microstructure has been successfully synthesized from Ba(NO3)2 4H2 O and Na2 MoO4 2H2 O as starting materials in ethylene glycol solvent containing 20 mL 5 M NaOH by microwave radiation at 180Wfor 30 min. The assynthesized BaMoO4 product was characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, Raman spectrophotometry, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and photoluminescence (PL) spectroscopy. XRD patterns revealed that the products was tetragonal BaMoO4 phase. SEM and TEM characterization showed that the product had a shuttle-like BaMoO4 microstructure. PL of the shuttle-like BaMoO4 microstructure showed a maximum emission at 466 nm excited by 280 nm wavelength.

17

Recording of the Particular Matter Behaviour when Leaving a Container

Vyletelek J., Gelnar D., Zidek M., Zurovec D., Jezerska L.

Inżynieria Mineralna

|

2015

|

R. 16, nr 2

201--206

EN

The article focuses on behaviour of particular matter depending on marginal conditions with application of the PIV (Particle Image Velocimetry) and DEM (Discrete Element Method). The Discrete Element Method was used for validation of the particular matter behaviour. The research on the bulk material behaviour concentrated on detection of changes of velocity in experimental materials under constant marginal conditions. The marginal condition is an obstacle on the bottom of the storage tank. As experimental material, we selected glass balls of various sizes. The diameter of the particles was 5 and 3 mm. These particles were mixed in a 50/50 proportion up to the capacity of the experimental sample. The output velocity was recorded by a high-speed camera and compared with numerical simulation in the DEM program. The resulting values of the particle velocity in both the PIV and DEM method were compared. The agreement between the experimental outputs and the numerical method in comparison of the flow velocity was on a high level. From results is possible to detect the period when all particles left the tested zone from charts illustrating the average velocity of all particles in the selected areas during drainage of the tank. By comparison of the locations with the period of the flow's termination in the individual zones we can declare that in the course of the flow, the matter leaves the higher delimited zones earlier than zones closer to the outlet hole. The time difference of the mutually successive zones then becomes shorter while approaching the outlet hole. To summarize the whole experiment complexly, we can declare that the particular matter is accelerated towards the outlet hole by action of the 30° incline of the hopper wall. In an area outside the outlet hole, this acceleration occurs especially in the x axis before the matter arrives above the discharge hole, where the core flow is under way and the direction of the matter's acceleration changes from the x axis to the y axis.

PL

W artykule skupiono się na zachowaniu pyłu zawieszonego w zależności od warunków brzegowych z użyciem analizatora obrazu cząstek (ang. skrót PIV – Particle Image Velocimetry) oraz metody elementów dyskretnych (ang. skrót DEM). Metody elementów dyskretnych użyto w celu określenia zachowania pyłu zawieszonego. Badanie materiału sypkiego skupione było na wykryciu zmian w prędkości materiału wysypującego się ze zbiornika, w stałych warunkach brzegowych. Jako materiał eksperymentalny użyto szklane kule o różnych średnicach. Średnice wynosiły 5 oraz 3 mm. Kule wymieszano w proporcji 50/50, aż do osiągnięcia objętości próbki eksperymentalnej. Prędkość wyjściowa została zarejestrowana przez kamerę i porównana z symulacją numeryczną w programie DEM. Porównano uzyskane wyniki określenia prędkości cząstek z obu metod PIV i DEM. Zależność między wynikami eksperymentalnymi i prędkością strumienia wyznaczoną metodą numeryczną była na wysokim poziomie. Dzięki wynikom z wykresów przedstawiających średnią prędkość cząstek na wybranych powierzchniach można określić moment, w którym wszystkie cząstki opuściły badaną przestrzeń. Można stwierdzić, że w przepływ strumienia materiału opuszczającego zbiornik nie jest jednolity. Można stwierdzić, że pył zawieszony przyspiesza w kierunku odbioru, przy 30° kącie nachylenia ściany zbiornika.

18

Wpływ obciążenia silnika 1.9 TDI VW na stężenie ilościowe i masowe nanocząstek w spalinach

Cisek J.

Zeszyty Naukowe Instytutu Pojazdów / Politechnika Warszawska

|

2014

|

z. 1/97

81--88

PL

Transport jest podstawowym źródłem emisji cząstek stałych PM. Emisja cząstek stałych silników spalinowych stanowi potencjalnie niekorzystne skutki dla zdrowia. Efekty te obejmują raka i inne choroby płuc oraz układu krążenia. Znaczna część cząstek jest bardzo drobna. Dla przykładu – milion cząstek 100 nanometrowych (o gęstości 1 g/cm3) ma masę około 0,0005g. Zatem ważą tyle co jedna cząstka o rozmiarze 10 mikrometrów. Artykuł zawiera wyniki badań masowej i liczbowej koncentracji nanocząstek PM w spalinach silnika 1,9 TDI VW, zasilanego standardowym olejem napędowym. Pomiary przeprowadzono dla powietrza otoczenia i 3 różnych punktów pracy silnika (bieg jałowy oraz małe i duże obciążenie przy 2000 obr/min). Do pomiarów nanocząstek używano Electrical Low Pressure Impactor ELPI firmy DECATI. Stwierdzono m.in., że największe stężenie masowe PM było dla cząstek o rozmiarach 0,1-10 m natomiast największe stężenie liczbowe dla 0,01- 0,1 m, a więc o rząd wielkości mniejszych niż dla stężenia masowego. Pomiary tego typu są istotne nie tylko w sensie utylitarnym, ale również poznawczym – do określenia wpływu parametrów konstrukcyjnych i regulacji silnika (bądź składu paliwa) na masę i liczbę nanocząstek emitowanych w gazach spalinowych.

EN

Transport is a major source of the particle pollution (PM). Combustion engine particulate emissions have the potential cause adverse health effects. These effects include cancer and other pulmonary and cardiovascular diseases. A substantial proportion of the number of particles, but not the mass, is ultrafine. For example – one million particles of 100 nanometers size with a unit density of 1 g/cm3 have a mass of approximately 0.0005 g. The paper includes research results of mass and number concentration of nanoPM for 1.9 TDI VW exhaust gases fuelled standard diesel fuel. The measurements were performed for ambient air and 3 different point of engine work (idle speed, low and high load at 2000 rpm). For nanoPM measurements was used Electrical Low Pressure Impactor ELPI from DECATI. Was found, among other things, that the biggest mass concentration was at 0,1-10 m of PM diameter but the biggest number concentration was at 0,01- 0,1 m and thus for the size of solid particles of at least an order of magnitude smaller than the mass concentration. Such measurements are important not only in terms of utilitarian but also in cognitive sense - for determining the effect of the engine construction parameters and/or regulating the engine (or the fuel composition) on the mass and the number of nanoparticles emitted in the exhaust gases.

19

Symulowanie topnienia lodu z wykorzystaniem procesorów graficznych

Domaradzki J., Chabko K., Martyn T.

Pomiary Automatyka Kontrola

|

2014

|

R. 60, nr 7

429--431

PL

W artykule przedstawiono metodę symulowania topnienia obiektów zbudowanych z lodu, implementowaną przy wykorzystaniu możliwości obliczeniowych nowoczesnych procesorów graficznych (GPU). Proces topnienia zrealizowano jako rezultat wymiany ciepła pomiędzy obiektami lodowymi i płynami (woda i powietrze), modelowanymi jako zbiory ruchomych cząstek o określonych parametrach fizycznych. Do obliczenia ruchu cząstek wykorzystano wariant algorytmu SPH. Zaprezentowano nowy cząstkowy model powietrza, który pozwala m.in. na uwzględnienie w symulacji lokalnych zmian temperatury powietrza w czasie. Otrzymywane wyniki symulacji są bardziej realistyczne z punktu widzenia poprawności fizycznej i końcowego efektu wizualnego, aniżeli rezultaty otrzymywane przy użyciu metod poprzednich.

EN

The paper presents a fast GPU-based approach to simulation of melting ice objects at interactive frame rates. Our main contribution is a new particlebased model of air which allows one to take into account in simulation the effects of local changes in the air temperature. The process of melting is realized as heat transfer between ice and fluids (water and air), which are represented by means of sets of movable particles (Fig. 2). To convert the triangle-mesh representation of solids into particles, we use a GPU-based voxelization method [4]. Each particle carries some physical local properties of fluid, and their evolution over time is described by the Navier-Stokes equation for incompressible fluids. In order to solve the equation, we utilize a modified version of Smoothed Particle Hydrodynamics (SPH) method [6]. Then, triangle meshes of solids are extracted from the particle representation using marching cubes algorithm, and visualized via ray tracing. Thanks to the new model of air, the results of ice melting supplied by our method (Fig. 3) are more realistic from the standpoint of physical correctness as well as visual appearance than those obtained with the previous approaches.

20

Surface probability model for estimation of size distribution on a conveyor belt

Zhang Z, Yang J., Dou D.

Physicochemical Problems of Mineral Processing

|

2014

|

Vol. 50, iss. 2

591--606

EN

Estimation of size distribution by image analysis is a key issue in mineral engineering. However, only the surface information of ore piles can be captured, which is a headache problem in this field while only a few researchers pay attention to this problem. A new surface probability model was proposed for estimation of size distribution on a conveyor belt based on the Chavez Model in this investigation. This model was tested and verified to have smaller errors in single size fraction but have bigger errors in multiple size fractions. Several error trends were found and a correction factor was introduced to correct the higher errors. A series of linear equations were developed to calculate this specific correction factor according to Dm (average particle size) and the height of pile. Therefore, empirical probability can be estimated by the specific correction factor and calculated probability, and the surface information of ore piles can be converted into the global information of piles.