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1
Content available Modeling of Melting and Resolidification in Domain of Metal Film Subjected to a Laser Pulse
Majchrzak E., Mochnacki B.
Archives of Foundry Engineering
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2016
|
Vol. 16, iss. 1
41--44
EN
Thermal processes in domain of thin metal film subjected to a strong laser pulse are discussed. The heating of domain considered causes the melting and next (after the end of beam impact) the resolidification of metal superficial layer. The laser action (a time dependent bell-type function) is taken into account by the introduction of internal heat source in the energy equation describing the heat transfer in domain of metal film. Taking into account the extremely short duration, extreme temperature gradients and very small geometrical dimensions of the domain considered, the mathematical model of the process is based on the dual phase lag equation supplemented by the suitable boundary-initial conditions. To model the phase transitions the artificial mushy zone is introduced. At the stage of numerical modeling the Control Volume Method is used. The examples of computations are also presented.
2
Content available Dual Phase Lag Model of Melting Process in Domain of Metal Film Subjected to an External Heat Flux
Mochnacki B., Ciesielski M.
Archives of Foundry Engineering
|
2016
|
Vol. 16, iss. 4
85--90
EN
Heating process in the domain of thin metal film subjected to a strong laser pulse are discussed. The mathematical model of the process considered is based on the dual-phase-lag equation (DPLE) which results from the generalized form of the Fourier law. This approach is, first of all, used in the case of micro-scale heat transfer problems (the extremely short duration, extreme temperature gradients and very small geometrical dimensions of the domain considered). The external heating (a laser action) is substituted by the introduction of internal heat source to the DPLE. To model the melting process in domain of pure metal (chromium) the approach basing on the artificial mushy zone introduction is used and the main goal of investigation is the verification of influence of the artificial mushy zone ‘width’ on the results of melting modeling. At the stage of numerical modeling the author’s version of the Control Volume Method is used. In the final part of the paper the examples of computations and conclusions are presented.
3
Content available Effect of Tungsten and Molybdenum on the Crystallization, Microstructure and Properties of Silumin 226
Szymczak T., Gumienny G., Pacyniak T., Walas K.
Archives of Foundry Engineering
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2015
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Vol. 15, iss. 3
61--66
EN
The work presents the results of the examinations of silumin 226 as well as a silumin produced on its basis containing a W and Mo addition introduced in the amount of 0.1; 0.2; 0.3 and 0.4% of both elements simultaneously. Investigations of the crystallization process of the silumins by the TDA method were conducted. Also, a microscopic analysis of their microstructure was performed and their basic mechanical properties were determined. Microstructure tests were made on casts produced in an TDA sampler as well as by the pressure method. The investigations exhibited a change in the course of crystallization of the silumin containing 0.3 and 0.4% W and Mo with respect to silumin 226 and the silumin with the addition of 0.1 and 0.2%. The presence of additional phases which did not occur in the case of lower addition contents was established in the silumin containing 0.3-0.4% W and Mo, regardless of the applied casting technology. The tests showed the possibility of increasing the tensile strength Rm, the proof stress Rp0,2 and the unit elongation A of the silumin as a result of a simultaneous introduction of the W and Mo addition. The highest values of Rm, Rp0,2 and A were obtained in the silumins with the additions of these elements within the range of 0.1-0.2% each.
4
Content available remote Mała elektrownia wiatrowa wspomagająca istniejący system grzewczy w budynku mieszkalnym. Część II. Małe elektrownie wiatrowe do ogrzewania pomieszczeń i przygotowania ciepłej wody w budynkach mieszkalnych
Wojciechowski H.
Instal
|
2013
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nr 7/8
20--29
PL
W części drugiej artykułu przedstawiono: dobór rodzaju i wielkości małej elektrowni wiatrowej do współpracy z istniejącymi systemami ogrzewania pomieszczeń i przygotowania ciepłej wody w budynku mieszkalnym oraz analiza celowości stosowania tego typu rozwiązań z ekonomicznego punktu widzenia.
EN
The second part of the article will be presented: the selection of the type and size of a small wind turbine to work with existing heating and hot water preparation in a family home and analysis of the advisability of that kind of technology from an economic point of view.
5
Content available remote Mała elektrownia wiatrowa wspomagająca istniejący system grzewczy w budynku mieszkalnym. Część I. Energetyczne wykorzystanie strumienia powietrza
Wojciechowski H.
Instal
|
2013
|
nr 5
8-13
PL
Przedstawiono wykorzystanie energii strumienia powietrza w małej elektrowni wiatrowej do wspomagania istniejących urządzeń do ogrzewania pomieszczeń i przygotowania ciepłej wody w budynku mieszkalnym. Artykuł składa się z dwóch części. W części pierwszej przedstawiono zagadnienia związane z pozyskiwaniem energii z poruszającego się strumienia powietrza oraz wpływu jego prędkości, warunków meteorologicznych i ukształtowania terenu na generację mocy przez małą elektrownię wiatrową W części drugiej artykułu zostaną przedstawione: dobór rodzaju i wielkości małej elektrowni wiatrowej do współpracy z istniejącymi systemami ogrzewania pomieszczeń i przygotowania ciepłej wody w budynku mieszkalnym oraz analiza celowości stosowania tego typu rozwiązań z ekonomicznego punktu widzenia.
EN
The paper presents the use of energy in a small stream of air to support wind power existing devices for space heating and domestic hot water in a family home. The article consists of two parts. The first part presents the issues relating to obtaining energy from a moving air stream and the impact of its speed, meteorological conditions and terrain for power generation by a small wind turbine The second part of the article will be presented: the selection of the type and size of a small wind turbine to work with existing heating and hot water preparation in a family home and analysis of the advisability of that kind of technology from an economic point of view.
6
Content available Model of Cu-Al-Fe-Ni bronze crystallization
Pisarek B. P.
Archives of Foundry Engineering
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2013
|
Vol. 13, iss. 3
72--79
EN
According to the analysis of the current state of the knowledge shows that there is little information on the process of phase transformations that occur during the cooling Cu-Al-Fe-Ni hypo-eutectoid bronzes with additions of Cr, Mo and/or W, made additions individually or together, for the determination of: the type of crystallizing phases, crystallizing phases, order and place of their nucleation. On the basis of recorded using thermal and derivative analysis of thermal effects phases crystallization or their systems, analysis of the microstructure formed during crystallization - observed on the metallographic specimen casting ATD10-PŁ probe, analysis of the existing phase equilibrium diagrams forming elements tested Cu-Al-Fe-Ni bronze, with additions of Cr, Mo, W and/or Si developed an original model of crystallization and phase transformation in the solid state, the casting of high quality Cu-Al-Fe-Ni bronze comprising: crystallizing type phase, crystallizing phase sequence, place of nucleation.
7
Content available Determination of heat accumulation coefficient for oil bonded moulding sands
Łągiewka M., Konopka Z., Zyska A., Nadolski M.
Archives of Foundry Engineering
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2013
|
Vol. 13, iss. 2
91--94
EN
The possibility of controlling the solidification and cooling time of castings creates prospects of improving their structure and by the same their properties. Thermal properties of the mould constitute therefore an important factor which is necessary to consider while seeking for the mentioned improvement. The presented work illustrates the method of determining some basic thermal coefficients of moulding material, i.e. the coefficient of temperature equalisation a2, known also as the temperature diffusivity, and the heat accumulation coefficient b2, which characterises the ability of moulding material to draw away the heat from a casting. The method consists in experimental determining the temperature field within the mould during the processes of pouring, solidification and cooling of the casting. The performed measurements allow for convenient and exact calculations of the sought-after coefficients. Examinations were performed for the oil bonded moulding sand of trade name OBB SAND ‘E’. The experiment showed that the obtained value of b2 coefficient differs from the value calculated on the basis of theoretical considerations available in publications. Therefore it can be stated that theoretical calculations of the heat accumulation coefficient are thus far not sufficient and not quite reliable, so that these calculations should be verified experimentally.
8
Content available Teoretyczne podstawy i realizacja idei zrównoważonego rozwoju w leśnictwie
Paschalis-Jakubowicz P.
Problemy Ekorozwoju
|
2011
|
Vol. 6, nr 2
101-106
PL
Użytkowanie lasu jest najstarszą formą działalności człowieka i zachodzi również, jeżeli odbywa się bez fizycz-nej obecności człowieka w lesie, stając się działaniem destrukcyjnym – zamierzonym lub niezamierzonym, lub działaniem kreatywnym – umożliwiającym identyfikację i realizację potrzeb. Użytkowanie takich funkcji lasu jak: kulturowa, moralna, etyczna, religijna i wiele innych, nie zawsze jest kwantyfikowalne, a ich bezpośrednia wycena, w tym ekonomiczna, może być bardzo trudna. Spowodowane jest to zarazem brakiem odpowiednich narzędzi ekonomicznych, jak i metod bezpośrednich analiz środowiskowych, a także nieumiejętnością identyfi-kacji poszczególnych funkcji, jakie pełnią lasy. Artykuł przybliża historię zrównoważonego rozwoju w leśnictwie, poczynając od nakazu dbania o las podpisa-nego w 1364 r. Kolejni, wielcy teoretycy i praktycy leśni (Carlovitz, Cotta, Hundeshagen, Heyer), budowali zwartą, przemyślaną konstrukcje postępowań rozpatrując problemy utrzymania trwałości, ciągłości i równo-mierności użytkowania lasu. Realnym problemem w realizacji koncepcji zrównoważonego leśnictwa i wielofunkcyjnego lasu, jest nierozwią-zywalna trudność w antycypacji oczekiwań przyszłych generacji, co do stanu, wyglądu i zróżnicowania przy-szłych lasów. Należy przy tym zauważyć, że obietnice, jakie niosą za sobą pojęcia używane w zrównoważonej gospodarce leśnej, w odniesieniu do wielofunkcyjności leśnictwa nie mogą być spełnione jednocześnie i na-tychmiast. W praktyce leśnej, wszystkie funkcje jakie pełni las, mogą być spełnione jedynie w bardzo długim horyzoncie czasowym – liczonym długością życia drzew i drzewostanów. Poszukiwania rozwiązań w tym zakresie, powinny obejmować nie tylko obszary nowoczesnej, aktualnej wiedzy, zarówno leśnej, jak i w innych działów nauki, ale także, wiedzy tradycyjnej. To oznaczałoby, również pogodze-nie się z myślą, że wiedza tradycyjna, nie zawsze poparta naukowym oglądem, może być podstawą zrozumienia wielofunkcyjności lasu w kontekście zrównoważonego rozwoju.
EN
Use of the forest is the oldest form of human activity and also occurs if it takes place without the physical pres-ence of man in the woods, becoming destructive action – intentional or unintentional, or creative activity – iden-tifying and implementing specific needs. Use of forest functions such as: cultural, moral, ethical, religious, and many others, is not always quantifiable, and their direct measurement and evaluation, can be very difficult. This is due to both lack of appropriate economic tools and methods for the direct environmental analysis, as well as an inability to identify the various functions played by forests. The article is discussing the history of sustainable development in forestry, which opens with the law signed in 1364 by Philip VI of France, ordering that owners of the forest must take care of it. The next great theorists and practitioners of Forestry (Carlovitz, Cotta, Hundeshagen, Heyer), develop the concept, building a cohesive, well thought-structures of proceedings in the context of preserving stability, continuity and uniformity forest use. The real problem in implementation of the concept of sustainable forestry and forest multifunctionality, is un-solvable difficulty in anticipating the expectations of future generations as to the condition, appearance and composition of future forests. should be noted that promises benefits of the terms used in sustainable forest man-agement (SFM), in relation to the multifunctional forestry cannot be met simultaneously and immediately. In forestry practice, all the forest functions, can be met only in a very long time horizon – calculated life expectancy of trees and stands. The search for solutions in this area should include not only areas of the modern, current knowledge, both the forest and in other branches of science, but also traditional knowledge. This would mean, that traditional know-ledge, significantly important for the practice of forestry, can be the basis for the understanding of the multi-functionality of the forest in the context of sustainable development.
9
Content available remote The phosphorus interaction on the process forming of primary structure of hypereutectic silumins
Piątkowski J.
Archives of Foundry Engineering
|
2009
|
Vol. 9, iss. 3
125-128
EN
In this work the results of investigations concerning the hypereutectic silumins to be used as engine ports have been show. New idea on the interaction mechanism of phosphorus during modification of hypereutectic silumins has been shown. According to this hypothesis the influence of phosphorus is the result of local supercooling caused by evaporation and decompression of phosphorus steam. On the base to propose schematic diagram of the origin of local supercooling as a result of evaporation of phosphorus un microareas with a diversified concentration of silicon of the investigated Al-Si alloys.
10
Content available remote Temperature drop of liquid iron in thin wall channels during mold filling
Górny M.
Archives of Foundry Engineering
|
2009
|
Vol. 9, iss. 1
137-142
EN
This work deals with first period of metal cooling in mold cavity. It has been performed thermal analysis of flooding metal stream in thin wall ductile iron with the shape of Archimedes spirals. It has been presented comparison of real temperature drop with predictions according to the analytical equations based on heat balance and with simulation using Fluent program. Additionally velocity decrease predicted by Fluent program is compared to the experimental data. Moreover change of cooling rate as function of spiral length of liquid metal before eutectic solidification is presented.
11
Content available remote Development of the fundamentals of melting and casting technology of Al-Me (Cr, Ni, Mo, W, Ti) master alloys used for modification of microstructure in silumins
Piątkowski J.
Archives of Foundry Engineering
|
2009
|
Vol. 9, iss. 2
17-20
EN
The study presents the technological backgrounds of the process of melting and casting Al-Cr, Al-Ni, Al-Mo, Al-W and Al-Ti master alloys, used as refiners of the microstructure of cast silumins. Basing on the analysis of phase equilibrium diagrams for an Al-Me (Cr, Ni, Mo, W, Ti) system at a temperature of 900oC, the characteristic intermetallic phases of AlxMey were investigated. Due to their similarity with Al and Si in respect of both structure and lattice arrangement, these phases may act as heterogeneous nuclei and promote solution hardening during, e.g., heat treatment. Using the method of thermal analysis ATD, the temperature was plotted in function of time, and then the characteristic values of the solidification parameters of master alloys were read out from the respective curves.
12
Content available remote Elektrochromatografia kapilarna : teoretyczne podstawy i zastosowania
Malinowska I., Drozdzowski M., Bojarski J.
Wiadomości Chemiczne
|
2005
|
[Z] 59, 9-10
771--789
EN
In this article the theoretical basis of capillary electrochromatography are presented, as well as some of its analytical applications. The historical background of this analytical method is briefly outlined. The nature of Helmholtz and Stern double layer at the phase boundary resulting in the electroosmotic flow (EOF) and the equations describing its velocity are shortly discussed. From these equations it follows that EOF depends on the properties of liquid phase (a ratio of dielectric constant to viscosity), the electric field intensity and the electric double layer (ζ potential) but does not depend on the diameter of particles of column or capillary packing. The relationship between EOF and efficiency of the chromatographic system is discussed and some advantages and disadvantages of electrochromatography are mentioned. The columns (capillaries) used in electrochromatography (packed, open tubular and monolytic) are described. The applications of capillary electrochromatography described here encompass enantioselective analysis and separation of mixtures of analytes. The examples of enantioseparations deal mainly with drugs, whereas electrochromatographic separations of mixtures are exemplified by amino acids, peptides, proteins and some groups of drugs (barbiturates and benzodiazepines). It is concluded that electrochromatography, although relatively "young" analytical method, found important applications and is in the phase of constant development.
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