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EN
The paper presents the results of an investigation of the gases emission of moulding sands with an inorganic (geopolymer) binder with a relaxation additive, whose main task is to reduce the final (residual) strength and improves knocking-out properties of moulding sand. The moulding sand without a relaxation additive was the reference point. The research was carried out using in accordance with the procedure developed at the Faculty of Foundry Engineering of AGH - University of Science and Technology, on the patented stand for determining gas emissions. Quantification of BTEX compounds was performed involving gas chromatography method (GC).The study showed that the introduction of relaxation additive has no negative impact on gas emissions - both in terms of the total amount of gases generated, as well as emissions of BTEX compounds. Among the BTEX compounds, only benzene is emitted from the tested moulding sands. Its emission is associated with the introduction a small amount of an organic hardener from the group of esters.
EN
The problem of harmful casting resins has been present in foundries for many years. Manufacturers are introducing new products that contain in their composition environmentally and eco-friendly ingredients. Unfortunately, not all types of technology can be used, sometimes environmental benefits are disproportionate to the quality of castings and their price. In the foundry industry, the most popular binders are based on organic compounds (often carcinogenic) and other harmful substances. Due to strict legal regulations regarding environmental protection, as well as care for the foundry's workers' comfort - their occurrence should be reduce to a minimum. These compounds often behave also depending on the conditions of use (temperature, atmosphere). The application of various methods of thermal analysis and spectroscopic methods allows to verify the mechanism of resin decomposition process in relation to conditions in the form in both inert and oxidizing atmosphere. For analysis the resins from cold-box technology, were used TG–DTG–DSC, Py-GC/MS methods and specified the course of changes occurring in combination of different atmosphere.
EN
This paper focuses on the thermal behavior of the starch-based binder (Albertine F/1 by Hüttenes-Albertus) used in foundry technology of molding sand. The analysis of the course of decomposition of the starch material under controlled heating in the temperature range of 25- 1100°C was conducted. Thermal analysis methods (TG-DTG-DSC), pyrolysis gas chromatography coupled with mass spectrometry (Py- GC/MS) and diffuse reflectance spectroscopy (DRIFT) were used. The application of various methods of thermal analysis and spectroscopic methods allows to verify the binder decomposition process in relation to conditions in the form in both inert and oxidizing atmosphere. It was confirmed that the binder decomposition is a complex multistage process. The identification of CO2 formation at set temperature range indicated the progressive process of decomposition. A qualitative evaluation of pyrolysis products was carried out and the course of structural changes occurring in the presence of oxygen was determined based on thermo-analytical investigations the temperature of the beginning of binder degradation in set condition was determined. It was noticed that, significant intensification of Albertine F/1 sample decomposition with formation of more degradation products took place at temperatures above 550ºC. Aromatic hydrocarbons were identified at 1100ºC.
EN
The intercalation into interlayer spaces of montmorillonite (MMT), obtained from natural calcium bentonite, was investigated. Modification of MMT was performed by the poly(acrylic acid-co-maleic acid) sodium salt (co-MA/AA). Efficiency of modification of MMT by sodium salt co-MA/AA was assessed by the infrared spectroscopic methods (FTIR), X-ray diffraction method (XRD) and spectrophotometry UV-Vis. It was found, that MMT can be relatively simply modified with omitting the preliminary organofilisation – by introducing hydrogel chains of maleic acid-acrylic acid copolymer in a form of sodium salt into interlayer galleries. A successful intercalation by sodium salt of the above mentioned copolymer was confirmed by the powder X-ray diffraction (shifting the reflex (001) originated from the montmorillonite phase indicating an increase of interlayer distances) as well as by the infrared spectroscopy (occurring of vibrations characteristic for the introduced organic macromolecules). The performed modification causes an increase of the ion exchange ability which allows to assume that the developed hybrid composite: MMT-/maleic acid-acrylic acid copolymer (MMT-co- MA/AA) can find the application as a binding material in the moulding sands technology. In addition, modified montmorillonites indicate an increased ability for ion exchanges at higher temperatures (TG-DTG, UV-Vis). MMT modified by sodium salt of maleic acid-acrylic acid copolymer indicates a significant shifting of the loss of the ion exchange ability in the direction of the higher temperature range (500–700°C).
PL
W artykule przedstawiono wpływ informacji oraz systemu informacyjnego na proces podejmowania decyzji przez menadżerów (kierowników średniego szczebla) w administracji publicznej a także czynniki i bariery racjonalnego podejmowania decyzji. Dodatkowo, zaprezentowano teoretyczny model badawczy podejmowania decyzji w administracji publicznej i na tej podstawie przeprowadzono badania empiryczne w przykładowej jednostce ZUS.
EN
The article presents the impact of information and information system on the decision making process by middle managers in public administration as well as factors and barriers to rational decision making. In addition, it was presented the theoretical research model for decision making in public administration. Empirical studies were carried out in the example unit of ZUS.
EN
The paper presents the results of an investigation of the thermal deformation of moulding sands with an inorganic (geopolymer) binder with a relaxation additive, whose main task is to reduce the final (residual) strength and improves knocking-out properties of moulding sand. The moulding sand without a relaxation additive was the reference point. The research was carried out using the hot-distortion method (DMA apparatus from Multiserw-Morek). The results were combined with linear deformation studies with determination of the linear expansion factor (Netzsch DIL 402C dilatometer). The study showed that the introduction of relaxation additive has a positive effect on the thermal stability of moulding sand by limiting the measured deformation value, in relation to the moulding sand without additive. In addition, a relaxation additive slightly changes the course of the dilatometric curve. Change in the linear dimension of the moulding sand sample with the relaxation additive differs by only 0.05%, in comparison to the moulding sand without additive.
EN
It was found that the addition of carbon fibers (CFs) does not affect the crosslinking process in the microwave radiation (800 W, 2.45 GHz) of the BioCo2 binder, which is a water solution of poly(acrylic acid) and dextrin (PAA/D). It has influence on BioCo2 thermal properties. The CFs addition improves the thermostability of a binder and leads to the reduction of gas products quantity generated in the temperature range of 300-1100°C (TG-DTG, Py-GC/MS). Moreover, it causes the emission of harmful decomposition products such as benzene, toluene, xylene and styrene to be registered in a higher temperatures (above 700°C). BioCo2 binder without CFs addition is characterized by the emission of these substances in the lower temperature range. This indicates the positive effect of carbon fibers presence on the amount of released harmful products. The selected technological tests (permeability, friability, bending strength, tensile strength) have shown that the moulding sand with the 0.3 parts by weight carbon fibers addition displays the worst properties. The addition of 0.1 parts by weight of CFs is sufficient to obtain a beneficial effect on the analyzed moulding sands properties. The reduction of harmful substances at the higher temperatures can also be observed.
EN
In many foundries, the requirements placed on castings production have risen mainly over the few years. Further trends in recent years have been the ever increasing level of automation and introduction of new alloys, especially composites. On the other hand, the foundry environment has become increasingly difficult because is used many organic binders. Environmental regulations will be further tightened up. These processes are pursued at national, European and global level. Conformity with emission limits is becoming increasingly difficult. The problem is emission of aromatic hydrocarbons, phenol, odours and other harmful compounds to environment. The main purpose of many companies is reduction of this toxins. The new cold-box systems (based on phenolic resins) try to reduce the emission by introducing into the resin structure silicate modifiers. Research presented of this article evaluate the effectiveness of these methods. The results show comparison of two resins ("without" and "with" silicate modifier) for assessment of emission of harmful aromatic hydrocarbons and phenol.
EN
The organo-inorganic commercial binder Albertine F/1 (Hüttenes-Albertus) constituting the starch-aluminosilicate mixture was directed to structural studies. The paper presents a detailed structural analysis of the binder before and after exposure to physical curing agents (microwaves, high temperature) based on the results of infrared spectroscopy studies (FTIR). An analysis of structural changes taking place in the binder system with the quartz matrix was also carried out. Based on the course of the obtained IR spectra, it was found that during the exposure on physical agents there are structural changes within the hydroxyl groups in the polymeric starch chains and silanol groups derived from aluminosilicate as well as in the quartz matrix (SiO2). The curing of the molding sand takes place due to the evaporation of the solvent water and the formation of intramolecular and intermolecular cross-linking hydrogen bonds. Type and amount of hydrogen bonds presence in cured molding sand have an impact on selected properties of molding sand. Results indicates that for molding sand with Albertine F/1 during conventional heating a more extensive network of hydrogen bonds is created.
PL
W niniejszym artykule zostały opisane niezbędne kompetencje oraz umiejętności potrzebne pracownikom administracji publicznej podczas wykonywania ich zadań. Szczególnie wyjaśniono znaczenie potencjału pracownika czyli jego umiejętności przystosowania się do nowych warunków, bardziej złożonych zadań, sytuacji, osobistej motywacji czy zaangażowania w pracę. W części empirycznej, na podstawie przeprowadzonego badania ankietowego, zaprezentowano wyniki dotyczące wiedzy, umiejętności i potencjału pracowników w jednym z Oddziałów Zakładów Ubezpieczeń Społecznych.
EN
This article describes the necessary competences and skills which are crucial for workers of public administration. The importance of the employee's potential was explained as the ability of adapting to new conditions, having more complex tasks, situations, personal motivation or engagement in work. The empirical part, based on the query survey, presents results concerning knowledge, skills and potential of employees in one of the Social Insurance Institutes.
PL
Proces wiązania poprzez polimeryzację metakryloamidu prowadzono in situ na osnowie kwarcowej w temperaturze 25°C oraz w polu mikrofal (150°C; 800 W; 2,45 GHz). Skład mieszaniny reakcyjnej, oprócz metakryloamidu – jako monomeru, zawierał: inicjator (nadsiarczan amonu), aktywator (N,N,N’,N’-tetrametyloetylenodimina), upłynniacz (sorbitol) oraz osnowę kwarcową. Zmiany strukturalne powstałe wskutek oddziaływań makromolekularnych w mieszaninie reakcyjnej podczas procesu polimeryzacji metakryloamidu, a dalej konsolidacji ziaren osnowy, określono metodą spektroskopii w podczerwieni przy użyciu spektrometru z transformacją Fouriera (FTIR). Stwierdzono, że podczas sieciowania powstają nowe wiązania w obrębie grup polarnych, typu: -OH, >NH, >C=O oraz silanolowych (Si-O). Ponadto przeprowadzono termoanalizę układu reakcyjnego w zakresie temperatury 25−500°C z zastosowaniem metody spektroskopii rozproszonego odbicia (FTIR-DRS). Badania te miały na celu określenie zakresu temperatury, w którym dochodzi do zmian związanych z sieciowaniem układu, a jeszcze nie jego termodestrukcją. Dla otrzymanego układu poreakcyjnego wykonano badania mikroskopowe metodą SEM. Uzyskana wiedza na temat procesu wiązania, poprzedzonego polimeryzacją metakryloamidu prowadzoną in situ na osnowie kwarcowej, pozwoli na podjęcie dalszych prac w obszarze technologii formowania i konsolidacji układów polimerowo-krzemianowych metodą druku 3D.
EN
The process of bonding by polymerization of methacrylamide was performed in situ on a quartz matrix at 25°C as well as in a microwave field (150°C; 800 W; 2.45 GHz). The composition of the reaction mixture, beside methylacrylamide as the monomer, was: the initiator (ammonium persulfate), the activator (N,N,N’,N’-tetramethylethylenediamine), the fluidizer (sorbit) and the quartz matrix. The structural changes occurring as a result of macromolecular reactions in the reaction mixture during the process of methacrylamide polymerization and then consolidation of the matrix grains, were determined by means of Fourier transform infrared spectroscopy (FTIR). It was found that during the cross-linking, new bonds are formed within the polar groups, of the following types: -OH, >NH, >C=O and silanol (Si-O). Also, a thermoanalysis of the reaction system was performed in the temperature range of 25−500°C with the use of dispersed reflection spectroscopy (FTIR-DRS). These studies aimed at determining the temperature range in which we can observe changes connected with the cross-linking of the system, and not its thermodestruction. For the obtained post-reaction system, SEM microscopic examinations were performed. The obtained knowledge of the bonding process, preceded by methacrylamide polymerization performed in situ on a quartz matrix, will make it possible to conduct further research in the scope of the technology of forming and consolidating polymer-silicate systems with the method of 3D printing.
PL
Do badań strukturalnych (FTIR) i termoanalitycznych (DRIFT) skierowano modyfikowaną skrobię w postaci soli sodowej karboksymetyloskrobi (CMS-Na0,6) w formie w yjściowej stanowiącej roztwór koloidalny oraz w postaci usieciowanej na drodze fizycznej (temperatura, promieniowanie mikrofalowe). Zmodyfikowaną skrobię CMS-Na0,6 otrzymano na drodze eteryfikacji skrobi ziemniaczanej. W pierwszej części artykułu przedstawiono analizę strukturalną CMS-Na0,6 przed i po usieciowaniu czynnikami fizycznymi w oparciu o wyniki badań spektroskopii w podczerwieni (FTIR) uzyskanych techniką transmisyjną. W drugiej części ustalono zmiany strukturalne w eteryfikowanej skrobi, stosując technikę spektroskopii rozproszonego odbicia w zakresie średniej podczerwieni (DRIFT), rejestrując widma on-line w zakresie temperatury 25−500°C. Na podstawie przebiegów otrzymanych widm IR stwierdzono, że podczas działania czynników fizycznych (temperatura, promieniowanie mikrofalowe) dochodzi do usieciowania koloidu CMS-Na0,6 wskutek całkowitego odparowania wody rozpuszczalnikowej, a dalej dehydratacji i utworzenia wewnątrzcząsteczkowych i międzycząsteczkowych sieciujących wiązań wodorowych. Metodą spektroskopową DRIFT ustalono postęp termicznego rozkładu, jakiemu CMS-Na0,6 podlegał podczas kontrolowanego wzrostu temperatury w zakresie 25−500°C. Ustalono, że proces degradacji termicznej rozpoczyna się już w temperaturze 280°C. Przeprowadzona analiza otrzymanych wyników badań strukturalnych stanowi dopełnienie prac badawczych w zakresie zastosowania eteryfikowanej skrobi jako spoiwa w technologii mas formierskich.
EN
Structural (FTIR) and thermo-analytic (DRIFT) studies were conducted on modified starch in the form of sodium salt of carboxymethyl starch (CMS-Na0.6) in the initial state, i.e. a colloidal solution, and in a cross-linked form prepared by physical means (temperature, microwave radiation). Modified starch CMS-Na0.6 was obtained by way of etherification of potato starch. The first part of the article presents the structural analysis of CMS-Na0.6 before and after cross-linking by means of physical factors based on the results of infrared spectroscopy tests (FTIR) obtained with the use of the transmission technique. The second part identifies the structural changes in the etherified starch with the use of Diffuse Reflectance Infrared Fourier Transform spectroscopy (DRIFT), recording the spectra in the temperature range of 25−500°C. Based on the courses of the obtained IR spectra, it was established that during the operation of physical factors (temperature, microwave radiation), cross-linking of the colloid CMS-Na0.6 was observed as a result of total evaporation of the solvent water and next dehydration and formation of intra- and intermolecular cross-linking hydrogen bonds. The spectroscopic method DRIFT was applied to determine the progress of the thermal decomposition of CMS-Na0.6 during a controlled temperature increase in the range of 25−500°C. It was established that the process of thermal degradation begins already at 280°C. The performed analysis of the obtained structural test results constitutes a complementation of the research conducted in the scope of applying etherified starch as a binder in moulding sand technology.
PL
W pracy przedstawiono wyniki badań spektralnych (FTIR, UV-Vis) przeprowadzonych dla próbek nieaktywowanego bentonitu (wapniowego) posiadającego w swym składzie główny składnik mineralny montmorylonit (MMT). MMT, jako składnik bentonitu zawierający jony wapnia (Ca-MMT), poddano modyfikacji na drodze fizycznej i chemicznej. Proces aktywacji fizycznej zainicjowano działaniem pola ultradźwięków (40 kHz). Modyfikację chemiczną Ca-MMT, poprzez wymianę jonową kationów wapnia na kationy potasu, przeprowadzono z udziałem modyfikatora w postaci węglanu potasu, przy czasie aktywacji równym 1 h. W celu określenia efektywności przeprowadzonej modyfikacji dla zmodyfikowanych fizycznie i chemicznie próbek montmorylonitu (K-MMT) w bentonicie przeprowadzono cykl badań analitycznych, w tym strukturalnych (FTIR) oraz spektrofotometrycznych (UV-Vis). Stwierdzono, że rodzaj i sposób prowadzenia modyfikacji, w tym zmiana czasu działania czynnika fizycznego na nieaktywowany bentonit, wpływa na zdolność do wymiany jonowej montmorylonitu (CEC). Zarówno zmodyfikowany fizycznie (ultradźwięki), jak i chemicznie (kationy potasu) MMT w bentonicie wapniowym wykazuje CEC na nieco niższym poziomie od CEC wyznaczonego dla stosowanego w technologii mas formierskich bentonitu sodowego. Zmodyfikowany MMT może więc stanowić alternatywny materiał wiążący do zastosowania w masach klasycznych.
EN
This paper presented the spectral study (FTIR, UV-Vis) for samples of non-activated bentonite (calcium) which has in its composition a main mineral resource, montmorillonite (MMT). MMT, as a component which contains calcium ions (Ca-MMT, was modified physically and chemically. The process of physical activations was initiated by an ultrasound field (40 kHz) with the use of a modificator in the form of potassium carbonate with an activation time of 1 h. To measure the efficiency of the modification for modified physically and chemically samples of montmorillonite (K-MMT) in bentonite there was performed a cycle of test including structural (FITR) and spectrofotometric (UV-Vis) analysis. It was stated that the type and method of making the modification including change of time in which physical factors are influencing the non-activated bentonite influences on the change of ion exchange of montmorillonite (CEC). Both modified physically (ultrasound) and chemically (potassium cations) MMT in calcium bentonite exhibits CEC on a slightly lower level than CEC used in the moulding sand technology of sodium bentonite. Modified MMT can be therefore used as an alternative material for green sand.
EN
TG-DTG-DSC, FTIR, DRIFT, and Py-GC-MS studies have been conducted to determine the effect of the thermal decomposition conditions and structure of foundry binder BioCo3 in the form of a composition poly(sodium acrylate)/dextrin (PAANa/D) on the progress of degradation in terms of processes occurring in foundry sands in contact with liquid metal. TG-DTG-DSC curves of the composition allowed us to determine the temperature range in which they do not undergo degradation, by which they do not lose their binding properties. With temperature increasing, physical and chemical changes occur that are related to the evaporation of solvent water (20–110°C), followed by the release of constitution water, and finally intermolecular dehydration (110–230°C). In this temperature range, processes that are mainly reversible take place. Within a temperature range of 450–826°C, polymer chains are decomposed, including the decomposition of side chains. Within a temperature range of 399–663°C, polymer composition decomposition can be observed (FTIR, DRIFT), and gas products are generated from this destruction (Py-GC-MS).
PL
W artykule zaprezentowano kontynuację zapoczątkowanych we wcześniejszych artykułach rozważań dotyczących sposobu opracowania konstrukcji i technologii wykonania dostatecznie skutecznego materiału opakowaniowego o właściwościach anizotropowych, który w niewielkim stopniu stanowiłby barierę dla wymiany ciepła podczas zamrażania, a z drugiej strony mógłby skutecznie chronić zamrożony produkt przed niekontrolowanym i szkodliwym oddziaływaniem środowiska zewnętrznego. W kolejnych przemyśleniach zmodernizowano opracowanie konstrukcji materiału i technologii wykonania przegrody termalnej. Zaproponowano nowy, bardziej rozwinięty model matematyczny oparty na równaniach przewodzenia ciepła w ośrodkach niejednorodnych obejmujący procesy przewodzenia, konwekcji i promieniowania cieplnego. Wykonano zaprojektowane kompozyty i przebadano je na specjalnie do tego celu zbudowanym stanowisku do pomiaru oporów cieplnych ciał stałych. Wyniki obliczeń zweryfikowano z wynikami badań eksperymentu. Uzyskano zgodność potwierdzającą teoretyczne rozważania o konstrukcji materiału „kierunkowego".
EN
The paper presents the continuation of the previous research papers on how to develop a design and technology to produce a sufficiently effective packaging material, which has anisotropic specificity, doesn't limit heat transfer during freezing and could protect a frozen product against uncontrolled and harmful influence of external environment in subsequent reflections, the development of the construction of the material and the technology of the thermal partition is modernized. A new, more advanced mathematical model based on heat conduction equations in heterogeneous media, including conduction, convection and heat radiation is proposed. Composite designs were made and tested on a specially designed bench for measuring the thermal resistance of solids. Results of calculations were verified by experimental work. Theoretical assumptions of the „directional" package construction were confirmed.
PL
Dynamiczny rozwój przemysłu powoduje wzrost wymagań rynku, narzuca dążenie do wytwarzania nowych produktów, bardziej sprawnych, niezawodnych, tańszych i bardziej ekonomicznych. Inżynierowie coraz częściej szukają inspiracji do rozwiązywania problemów technicznych i technologicznych w otaczającym nas środowisku naturalnym.
EN
The paper presents the results of thermoanalytical studies by TG/DTG/DTA, FTIR and GC/MS for the oil sand used in art and precision foundry. On the basis of course of DTG and DTA curves the characteristic temperature points for thermal effects accompanying the thermal decomposition reactions were determined. This results were linked with structural changes occurred in sample. It has been shown that the highest weight loss of the sample at temperatures of about 320°C is associated with destruction of C-H bonds (FTIR). In addition, a large volume of gases and high amounts of compounds from the BTEX group are generated when liquid metal interacts with oil sand. The results show, that compared to other molding sands used in foundry, this material is characterized by the highest gaseous emissions and the highest harmfulness, because benzene emissions per kilogram of oil sand are more than 7 times higher than molding sand with furan and phenolic binders and green sand with bentonite and lustrous carbon carrier.
EN
Emission of gases under high temperature after pouring molten metal into moulds, which contain the organic binder or other additives (solvents or curing agent), may be an important factor influencing both on the quality of the produced castings, and on the state of environment. Therefore, a comprehensive studies of the emitted gases would allow to determine restrictions on the use of the moulding sands in foundry technologies, eg. the probability of occurrence of casting defects, and identify the gaseous pollutants emitted to the environment. The aim of the research presented in this paper was to determine the amount of gases that are released at high temperatures from moulding sands bonded by biopolymer binder and the quantitative assessment of the emitted pollutants with particular emphasis on chemical compounds: benzene, toluene, ethylbenzene and xylenes (BTEX). The water-soluble modified potato starch as a sodium carboxymethyl starch with low (CMS-NaL) or high (CMS-NaH) degree of substitution was a binder in the tested moulding sands. A tests of gases emission level were conducted according to the procedure developed at the Faculty of Foundry Engineering (AGH University of Science and Technology) involving gas chromatography method (GC). The obtained results of the determination of amount of BTEX compounds generated during the decomposition process of starch binders showed lower emission of aromatic hydrocarbons in comparison with binder based on resin Kaltharz U404 with the acidic curing agent commonly used in the foundries.
EN
The effects of silica additive (Poraver) on selected properties of BioCo3 binder in form of an aqueous poly(sodium acrylate) and dextrin (PAANa/D) binder were determined. Based on the results of the thermoanalytical studies (TG-DTG, FTIR, Py-GC/MS), it was found that the silica additive results in the increase of the thermostability of the BioCo3 binder and its contribution does not affect the increase in the level of emissions of organic destruction products. Compounds from group of aromatic hydrocarbons are only generated in the third set temperature range (420-838°C). The addition of silicate into the moulding sand with BioCo3 causes also the formation of a hydrogen bonds network with its share in the microwave radiation field and they are mainly responsible for maintaining the cross-linked structures in the mineral matrix system. As a consequence, the microwave curing process in the presence of Poraver leads to improved strength properties of the moulding sand […]. The addition of Poraver's silica to moulding sand did not alter the permeability of the moulding sand samples, and consequently reduced their friability. Microstructure investigations (SEM) of microwave-cured samples have confirmed that heterogeneous sand grains are bonded to one another through a binder film (bridges).
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