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Wyświetlanie 1-6 z 6
Tytuł:
Technological applications of laser ablation in combustion engine pistons
Ablacja laserowa w zastosowaniach technologicznych dla tłoków silnika spalinowego
Autorzy:
Napadłek, W.
Powiązania:
https://bibliotekanauki.pl/articles/243652.pdf
Data publikacji:
2008
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
ablacja laserowa
warstwa powierzchniowa
tłok silnika spalinowego
usuwanie nawarstwień
laser ablation
surface layer
combustion engine piston
deposits removal
Opis:
The principles and possible applications of laser ablation technology in combustion engines pistons were described. Laser ablation removal of carbon deposits and other products of pistons using from pistons bottom was presented. The process of sequence removal of the deposits was controlled, so the pistons were not damaged. Nd: YAG laser with 10 Hz pulse work and wavelength X-- 1064 nm was applied during the process. In the laboratory experiments the deposits were removed from aluminum Akl12 and from ceramics on the basis of zirconium, sputtered on the pistons bottom as a thermal barrier (TBC). The exposition time of laser beam ranging from 10 to 20 ns was applied. Furthermore variation of such important parameters of laser treatment like energy density, beam scanning rate, impulse covering rate was applied, resulting with a set of parameters applicable for lab and even industrial scale. After deposits removal from surface layer, many micro- and macro cracks were noticed. The cracks created a net-like pattern, which was a result of cyclic heat-shock present during 400 hours long endurance test of combustion engine. The laser technique is an alternative for other methods because of its ecological reasons. It is also very precise and can be easily automated. It can be also applied in diagnosis, verification and also as a surface layer pretreatment for such a processes like thermal sputtering, or deposition of composite layers in important areas of pistons.
Opisano istotę oraz możliwości zastosowań technologicznych ablacji laserowej dla tłoków silnika spalinowego. Przedstawiono wybrane wyniki badań własnych w zakresie ablacyjnego usuwania nawarstwień, głównie w postaci nagaru na denku tłoka oraz innych osadów będących produktami eksploatacji tłoków. Usuwanie sekwencyjne nawarstwień realizowane było w sposób kontrolowany, dzięki temu nie następowało uszkadzanie podłoża tłoka. Ablacyjne oczyszczanie laserowe realizowane było przy użyciu lasera Nd: YAG o pracy impulsowej 10 Hz oraz długości promieniowania laserowego X = 1064 nm. W eksperymentach laboratoryjnych usuwano ww. nawarstwienia osadzone na podłożu ze stopu aluminium Ak12 oraz ceramiki na bazie cyrkonu, natryskanej na denko tłoka jako bariera termiczna (TBC). Stosując czas ekspozycji wiązki laserowej ok. 10 -20 ns oraz różne parametry obróbki laserowej: gęstość energii, prędkość skanowania wiązki, stopień przykrycia impulsów dobrano właściwe parametry obróbki, które mogą być stosowane nie tylko w warunkach laboratoryjnych, ale również w skali przemysłowej. Po usunięciu nawarstwień w warstwie wierzchniej barierowej powłoki ceramicznej stwierdzono bardzo liczne mikro-i makro-pęknięcia, tworzące regularną siatkę spękań, powstałą w czasie cyklicznych oddziaływań szoków cieplnych w 400 - godzinnej próbie trwałościowej silnika spalinowego o ZS. Opisywana technologia laserowa stanowi alternatywę dla innych metod oczyszczania, głównie ze względów ekologicznych, dużej precyzji oraz szerokich możliwości automatyzacji procesu. Może być wykorzystywana również w procesach diagnostyki i weryfikacji, a także, jako technologia przygotowania warstwy powierzchniowej do innych procesów technologicznych, np. natryskiwania cieplnego, osadzania powłok kompozytowych w newralgicznych strefach tłoków.
Źródło:
Journal of KONES; 2008, 15, 3; 382-388
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Konserwacja kamiennego portalu z Ołbina w kościele Marii Magdaleny we Wrocławiu
PRESERVATION OF THE STONE DOORWAY FROM OŁBIN IN THE ST. MAGDALENE CHURCH AT WROCLAW
Autorzy:
Domasłowski, Wiesław
Powiązania:
https://bibliotekanauki.pl/articles/538952.pdf
Data publikacji:
1970
Wydawca:
Narodowy Instytut Dziedzictwa
Tematy:
romański portal z Ołbina
piaskowce arkozowe
wzmacnianie kamienia
usuwanie nawarstwień z kamienia
impregnacja strukturalna portalu
odsalanie kamienia
Opis:
The Romanesque doorway from Ołbin whose origins may be dated as early back as to the late 12-th century was built from blocks of arkose sandstone. During the long course of history its state of preservation gradually deteriorated and thus it had many times to be subjected to conservating treatments. Its surface was, among the others, reinforced by means of liquid glass and chemicals of the fluosilicate group. It seems, however, that the treatments applied did not bring intended effects and this probably was the reason why one part of the doorway has been coated with cement milk whereas the others co-ered with a protective layer of a hardly distinguishable polymer-type organic matter. Nevertheless, these superficial coatings have proved to be unable to prevent advancing decay and the stones were getting more and more disintegrated, maybe at even higher rate as it was the case at earlier date. Finally, the layers next to the stone surface begun to split and exfoliate and from underneath poured the powdered sandstone. This increasing decay has led to substantial decrements in the total mass and also to deformations in the plastic appearance of the doorway. In effect of investigations carried out it became possible to find that these destructions were, in the first line, caused by the action of water-soluble salts and water penetrating into the doorway from the church interior which the both occurrences were due to the fact that the outer surfaces of walls have been faced with clinker bricks hardly permeable for water. Although several expert bodies were meeting with this object in mind no clearly outlined programme of preservation works for the said doorway has been worked out in conclusion. The works carried out within the first stage comprised the following measures: encasing of the doorway to protect it against the immediate weather influences (mainly the waters'), securing the fragments by glueing the paper on their surfaces, removing the clinker bricks from the immediate neighbourhood of the doorway, and, finally, building of a cellar under it to stop the flow of ground waters. The undertaking of a full-scale treatment has become possible only on completion of examination of possibilities to apply epoxy resin solutions for structural impregnation and also on working out of the s.c. pocket-type method for stone saturation. Investigations in this respect were conducted at the Copernicus University, Toruń to order of the Historical Monuments Documentation Centre, Warsaw. The conservating works themselves were carried on in the years 1967 and 1968 and their plan covered the actions named below: a) superficial strengthening of pouring, delaminating and exfoliating portions of stones from which the doorway is built, . b) reinforcement of the breaking away fragments of doorway with the application of putties and fillings, c) removing of the superficial built-up layers with the aim to restore the stone porosity and ipso facto enable the impregnation, d) removing the cement and gypsum putties and fillings by means of which the former decrements in stones were filled up, e) extraction of water-soluble salts, f) structural impregnation of the entire doorway with the aim to reinforce the deepest stone layers, g) filling with putties the holes and pin cracks. The superficial reinforcing of stones was carried out by means of the 20 per cent methylbenzene solution of epoxy resin. The resin was hardened by treating it with triethylenetetraamine. For reinforcing of stone fragments that have broken and exfoliated thus threatening to flake the putty has been applied obtained by mixing the epoxy resin with powdered sandstone in 1 : 15 proportion. The putty was filled into pin cracks and then pressed. With the putties hardened a durable junction was obtained between the loose fragments and their bed. Thanks to the properties possessed by existing built-up layers they could be removed with the use of either chemical or mechanical means. Chemically were removed the layers formed in result of an usual action exerted by atmospheric components, and the 3 to 6 per cent hydrofluoric acid was applied for this purpose. Portions on which the afore-mentioned built-up layers have been found comprised well under 10 per cent of the total doorway area. The layers consisting of cements and organic matter not soluble in solvents available were removed mechanically by means of scrapers. With the dark-coloured built-up layers removed the stones of which the doorway is composed have regained their original colour, texture and plasticity. (However, it has proved impossible to restore to the superficial stone layers their original porosity. The reinforcing substances with which the stone pores were filled are unremovable and their porosity could be restored only by means of grinding-off the superficial layers being, of course, an inadmissible practice. The cement putties and some gypsum putties, too, applied during the former restorations of the doorway were removed, for they contributed to the accelerated destruction of stones, in addition forming black spots on the brighter coloured background. On completion of the above-mentioned works the next stage has been started, consisting in removing of water-soluble salts. A method of their forced migration to paper layer was applied using the fivefold coating of the entire doorway with water saturated paper sheets. Already the fourth consecutive paper coating did not reveal the presence of salt. The above method allowed to remove the salts from pores next to the stone surface which the fact is due to limited permeability of water into the deeper stone layers in effect of earlier applied treatments (N. B. migration of salts occurs only in parts saturated with water). As the superficial impregnation of doorway carried out by means of epoxy resin solution is able to prevent decay for a limited period of time only it has been decided to reinforce the structure of the doorway stones in their deepest possible layers (structural impregnation). This treatment was carried out using 10 per cent toluene-and-methyl alcohol solution of epoxy resin in the respective proportion of 1 : 2 and 1 : 3. The amount of methyl alcohol present in 'Solution was deciding for the rate of resin precipitation from it. At the 1 : 2 proportion the precipitation was beginning after about 20 hours whereas at 1 : 3 after about l'O hours. The first of the above solutions was applied in cases in which the need occurred to saturate the stones for more than 12 hours, the other one — for saturation periods not reaching the time given above. Solutions were prepared in portions of 1 to 4 litres to which 15 per cent of triethylenetetraamine was added in proportion to resin amount. They were introduced into the doorway stones by means of s.c. pooket-type method. The pockets were prepared in such a way that on the stone surface were put 5 to 6 layers of the water-saturated paper onto which, starting from their edges, the gypsum mortar was imposed forming the 1 to 2 cms wide framing at all sides. In the upper parts of so formed lining a filler was made from a piece of paper and the whole covered with gypsum . The separate stages of the pocket-forming may easily be seen from illustrations. All the elements of doorway were covered with pockets. With the gypsum mortar dried the tightness of pockets was examined by means of solvents and leakages removed. The impregnation has been carried out by pouring the solution into pockets and its steady supplementing so that the pockets could be kept full throughout the entire period of saturation. During one-day operation were saturated the doorway elements with sizes allowing to complete saturation and removing the pockets themselves within 30 hours. It has been found that within this period the epoxy resin gel forming in gypsum pores was still thin enough to enable the easy removal of pockets. They could be removed without damaging the stones as the object after impregnation was secured with cellophane having inhibitory effect on evaporation of solvents. Since the rests of gypsum remained on the stone surfaces they had to be removed at once thus not permitting their hardening by the active resin. After cleaning operation the saturated elements were insulated by means of cellophane from the ambient atmosphere for a period of 10 to 14 days to allow the maximum rate of precipitation of resin from the solvent. Three hundred ninety litres of resin solution were used for this purpose of which the amount some 295 litres have been introduced into stone, the balance being absorbed by gypsum and lost during the operation. Within the last operation the supplementing of slight stone decrements in form of holes and pin cracks with the epoxy putties has been carried out. For this purpose, much the same as in the course of the above-described operation, a mixture composed of 1 part of epoxy resin and 15 parts powdered sandstone has been applied. To this mixture containing hardener (15 per cent) petroleum spirits were added to obtain better conditions for hardening. The putties prepared for this operation are characteristic of their higher degree of porosity at the same time showing good water-repellent properties and impact strength similar to that of actual stone. For preparing the putties the white sandstone powder was used so that after their hardening it proved necessary to patinate them together with traces left by pockets („crabs”) using mineral dyes with 1 per cent addition of epoxy resin solution acting as hardener. The illustrations show the doorway in state after preservation operations.
Źródło:
Ochrona Zabytków; 1970, 1; 11-27
0029-8247
Pojawia się w:
Ochrona Zabytków
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dekoracja malarska na sklepieniu kolegiaty pułtuskiej : odkrycie, konserwacja, rozwiązanie artystyczno-estetyczne
PAINTED DECORATION ON THE VAULT OF THE PUITUSK COLLEGIATE CHURCH - DISCOVERY, CONSERVATION, ARTISTIC-AESTHETIC SOLUTION
Autorzy:
Stawicki, Stanisław
Powiązania:
https://bibliotekanauki.pl/articles/536249.pdf
Data publikacji:
2002
Wydawca:
Narodowy Instytut Dziedzictwa
Tematy:
kolegiata pułtuska
Pułtusk
polichromia
malowidła ścienne
koncha apsydy
konserwacja malowideł
konserwacja dekoracji malarskiej
usuwanie nawarstwień
technika al fresco
punktowanie
rekonstrukcja
Opis:
The painted decoration embellishing the vault of the collegiate church in Pułtusk is one of the largest in Poland and totals about 700 sq. metres without the frieze (composed of architectural niches), which constitutes the lower part of the vault supported directly by northern and southern abutments. The polychrome was executed after 1551, the year of signing a contract with Master Wojciech of Warsaw. The vault polychrome assumed the form of stylised rosettes, fleurons and portrait-heads, inserted into the architectural-decorative configuration of the vault, which constitutes a net made of the alternate onion-shaped and circular forms, creating the so-called Pułtusk vault. After a fire in 1613, the interior of the church, including the vault, was painted over in a uniform colour, probably imitating the firmament. During the almost 300 years-long history of the church, the vault was frequently painted over in a single hue for aesthetic and hygienic reasons. The same purpose, which was to be realised in 1994, led to the discovery of the polychrome, first mentioned already in the seventeenth century. Routine research preceding the intended painting of the church interior confirmed the existence of polychrome decorations on the vault and, as could be assumed from initial work, also on the frieze. The discovery and ensuing conservation were accompanied by considerable interest on the part of the mass media, especially the press. Numerous widely read journals and popular scientific periodicals quoted characteristic comments and accounts from assorted communiques and newspaper notes. The value of those statements and their editorial form leave much to be desired, although they reflect concern for the historical monument and a readiness to stimulate interest in the fate of national culture. The disclosure and conservation of the painted decoration in Pułtusk constituted a serious effort of conservators of art. Suffice to emphasise that almost 3 cubic metres of six to nine assorted worthless layers of paint and lime whitening were removed in the course of uncovering the original polychrome. The conception and realisation of the best possible artistic-aesthetic solution posed a separate problem associated with work after routine technical operations. The state of the preservation of the polychrome and the character of the interior of the collegiate church, as well as its historical value and tourist assets imposed a solution (retouching and the reconstruction of the missing parts of the polychrome) which rendered the painted decoration legible, at the same time preserving its authentic ideological, stylistic and artistic character.
Źródło:
Ochrona Zabytków; 2002, 3-4; 326-338
0029-8247
Pojawia się w:
Ochrona Zabytków
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Zagadnienie wykorzystania ablacji laserowej w usuwaniu wtórnych nawarstwień z powierzchni dzieł sztuki i obiektów zabytkowych w architekturze
The Use of Laser Ablation in the Removal of Secondary Build-up from the Surface of Art Works and Monuments of Architecture
Autorzy:
Marczak, Jan
Powiązania:
https://bibliotekanauki.pl/articles/537824.pdf
Data publikacji:
2001
Wydawca:
Narodowy Instytut Dziedzictwa
Tematy:
ablacja laserowa
usuwanie wtórnych nawarstwień z powierzchni dzieł sztuki
usuwanie niepożądanych nawarstwień
usuwanie nawarstwień z zabytków kulturowych
czyszczenie laserem
czyszczenie laserowe
impulsowe promieniowanie laserowe
laser jako impulsowe źródło ciepła
laserowa ablacja nawarstwień i warstw powierzchniowych
impulsowa ablacja laserowa
absorpcja promieniowania laserowego
ablacja fototermiczną
fotoablacja
ablacja fotochemiczna
eksplozyjne odparowanie warstwy powierzchniowej
siły adhezji (przylegania)
selektywne usuwanie mikrocząstek
szybkość procesu ablacji laserowej
ciśnienie światła
zalety i wady laserowego czyszczenia powierzchni
wykorzystanie promieniowania laserowego w renowacji dzieł sztuki
Opis:
The article discusses problems associated with the use of laser ablation in the removal of secondary build-up from the surface of works of art and monuments of architecture as well as the removal of micro-particles from the surface of industrial elements. The prime problem connected with mechanical methods o f cleaning is the erosion of the original surface located immediately underneath the build-up, which sometimes causes irrecoverable losses and gaps in the details (e.g. reliefs, traces of the instruments used by the sculptor, or traces of polychromy). For several years now, the laser method has been successfully applied for the removal of secondary build-up, also in Poland, by resorting to laser impulse radiation. A laser impulse with suitable energy (power) density is capable of removing, for instance, black crusts from assorted surfaces without damaging the base, which at times can be more fragile and delicate than the build-up itself. The main purpose of the article is to acquaint the reader with a new technology of removing build-up with the assistance of laser impulse radiation. The author discusses physical mechanisms leading to the removal of particles and b uild-up from the surfaces of assorted material in the course of the impact of long (100-1000) gs and short (5-100) ns laser impulses. The article also considers other effects accompanying the process of ablation, and presents select research results. The summary mentions joint features linked with the laser ablation of different material and the assets and faults of the application of laser technique in conservation; it also p re sents the basic principles of safety while working with laser equipment. Finally, the au th o r proposes general conclusions associated with the removal of b u ild -u p with the help of laser radiation.
Źródło:
Ochrona Zabytków; 2001, 3; 233-251
0029-8247
Pojawia się w:
Ochrona Zabytków
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Zagadnienie usunięcia nawarstwień z powierzchni kamiennego portalu z Ołbina
PROBLÈME RELATIF À L’ENLÈVEMENT DES COUCHES DE LA SURFACE DU PORTAIL EN PIERRE PROVENANT DE OŁBIN
Autorzy:
Domasłowski, Wiesław
Powiązania:
https://bibliotekanauki.pl/articles/536691.pdf
Data publikacji:
1965
Wydawca:
Narodowy Instytut Dziedzictwa
Tematy:
portal romański
kościół św. Marii Magdaleny we Wrocławiu
portal z Ołbina
piaskowiec arkozowy
piaskowiec kwarcowy
spoiwo krzemionkowe
spoiwo ilasto-krzemionkowe
spoiwo wapienne
spoiwo węglanowe
lepiszcze krzemionkowo-wapienne
lepiszcze krzemionkowo-ilaste
struktura psamitowa
erozja kamienia
nawarstwienia na kamieniach
usuwanie nawarstwień
oczyszczanie kamieni
kwas fluorowodorowy
działanie kwasu fluorowodorowego
Opis:
Sur la base des épreuves effectuées, il fut établi que le moyen le plus efficace d’enlèvement des couches des grès est l ’acdde fluorhydrique. On a également examiné l ’influence qu’exerce cet acide et le temps de la saturation sur la résistance mécanique des grès d’un liant silicique, argildque et calcaire. Il fut constaté qu’assortissant les paramètres appropriés (concentration, durée), on peut non seulement enlever les couches mais également accroître la résistance des gîrès. En outre, il fut établi que le fluorure de calcium qui se forme en résultat de la réaction de l ’acide avec le liant calcaire n’exerce aucune influence sur l'augmentation de la résistance. Une hypothèse fut posée que le phénomène observé provient en résultat de la précipitation de la silice hydratée sur les grains de sable qui se forme en conséquence de l’hydrolyse du quadrifluorure du silicium. En cas de la désintégration du grès, l ’acide fluorhydrique n ’exerce aucune action de consolidation. Les essais de la purification de la pierre effectués à l ’aide de l’acide fluorhydrique (6°/o) (grès arcosiques d’un liant silico-argilique et silico-calcaire) du portail de l ’église Ste. Marie Madeleine donnèrent des résultats positifs. L’enlèvement des couches épaisses s ’est effectué sans endommagement de la surface de pierre.
Źródło:
Ochrona Zabytków; 1965, 3; 29-34
0029-8247
Pojawia się w:
Ochrona Zabytków
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pałac Krasińskich w Warszawie - stan zachowania i problemy ratowania dekoracji rzeźbiarskiej
The Krasiński Palace — State of Preservation and the Salvage of Sculpted Decoration
Autorzy:
Procyk, Wiesław
Powiązania:
https://bibliotekanauki.pl/articles/535787.pdf
Data publikacji:
2002
Wydawca:
Narodowy Instytut Dziedzictwa
Tematy:
Pałac Krasińskich w Warszawie
Tylman z Gameren
Jan Dobrogost Krasiński
Pałac Rzeczypospolitej w Warszawie
tympanon Pałacu Krasińskich
posągi Marsa i Ateny
rzeźba Marka Waleriusza
posąg Corvinusa
pomiar objętości porów efektywnych
porometr helowy
technologia konserwatorska rzeźb wolno stojących
erozja piaskowca
wietrzenie piaskowca
usuwanie nawarstwień
konserwacja rzeźb kamiennych
konserwacja piaskowca
impregnacja kamienia
zabezpieczenie hydrofobowe
Opis:
The articles discusses historical buildings or their fragments salvaged or recreated in the course of postwar reconstruction. Conservation frequently entails the necessity of decisive intervention in matter more than fifty years old. The concealed phase of the corrosion of steel connectors entails numerous threats. It is necessary to study the technology of fixtures applied in historical monuments; this holds true also for postwar reconstruction. Despite constant surrusion the non-symptom period is brief and has an uncontrolled course. Its consequences include the dramatic effects of the disintegration of the stone. In such situations the best option is the disassembly of the strained compositions, the elimination of threats, and a structural impregnation of the strained stone by means of petrification compounds. The assembly of the Krasiński Palace attic revealed the durability of water-repellent protection and its impact upon stratification and the methods of its removal. The most essential conclusion drawn from scanning and studies of porosity was the ascertainment of the cumulation of amorphous layers of siliceous-organic resin in the capillary systems under the stone surface in consecutive cycles of conservation. Individual research confirmed the reduction of the general diameter of effective pores after consolidation and impregnation. The last phase drew attention to the iconographie aspect of the depiction of a duel between Corvinus and a Gaul in the bas-relief decoration of the tympanum. An analysis of source material collected in the course of conservation demonstrated irrefutably th a t the postwar reconstruction of the elements of the sculpted decoration of this p a rt of the composition was not conducted to the very end or that the interpre tation was mistaken. A minute analysis of enlarged prewar photographs made it possible to make a new proposal of a reconstruction of the nonextant elements, thus restoring meaning to this part of the likeness. The article also brings the reader closer to the southern elevation of the palace (the bas-relief motif of the triumphant entry of Marcus Valerius Corvinus to Rome); here threats remain unresolved, the destruction of block makes headway, and details of the bas relief continue to be shed.
Źródło:
Ochrona Zabytków; 2002, 2; 170-185
0029-8247
Pojawia się w:
Ochrona Zabytków
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-6 z 6

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