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PLA filament is not equal to PLA filament: Experimental studies of the influence of the type of pigment on the mechanical and thermal properties of poly(lactic acid) products

Iwko Jacek, Jaruga Tomasz, Trzaska Oliwia, Stachowiak Tomasz

Materials Science Poland

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2023

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Vol. 41, No. 1

177-190

EN

The correct manufacture of products using FDM printers is not an easy task, taking into account the value and repeatability of material properties. The properties of elements manufactured in this way depend on many factors, both technological and material. Poly(lactic acid) PLA is one of the most willingly used materials in additive techniques. It is sold in a very wide range of colours. This work was intended to answer the question of how the type of pigment affects the mechanical and thermal properties of products obtained from PLA. The correlation between the material properties and the structure of the material as well as the macroscopic structure of the product has also been investigated. The paper analyses the mechanical and thermal properties of products made of PLA filaments in 12 basic colours obtained from one supplier. Bending, impact strength, HDT and Vicat softening point tests were carried out. The percentage content of residues after calcination the samples was determined. Additional analysis (DSC) was performed to interpret the obtained tests results. They indicate that the mechanical properties differ significantly between different types of PLA with differences of up to 45%. Vicat softening point tests indicate differences of 5°C between the extreme values of these parameters. The DSC interpretive study did not clearly show the reasons for these differences in the properties of the filaments.

2

Assessment of Indoor Microplastic Particles Pollution in Selected Sites of Mosul City

Al-Hussayni Rihab Salih, Al-Ahmady Kossay K., Mhemid Rasha Khalid Sabri

Journal of Ecological Engineering

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2023

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Vol. 24, nr 9

322--332

EN

Among the most significant sources of microplastics (MPs) for humans is indoor dust. However, very few researchers have studied the properties and abundance of MPs that existed in dust from different indoor environments. The current study investigated microplastic fallout in 90 locations (5 kindergartens, 6 mosques, 5 schools, 10 shops, 5 cafeterias, 6 hospitals, 25 dormitories, 7 barber salons, 6 offices, 5 scientific laboratories, 5 pharmacies, and 5 medical clinics) during six months. Among the ninety sampling sites, the most significant average of MPs was actually found in the kindergartens (4.743×103 ± 427 MP/m2 /d), in contrast, the lowest abundance was in the medical clinics (3.02×102 ± 62 MP/m2 /d). The majority of indoor dust samples contained MPs in the form of fibers. The dominant colour of dust samples was transparent, followed by black, red, blue, green, and yellow. A total of six types of polymers were identified, including polystyrene (PS, 39%), polyethylene terephthalate (PET, 20%), polypropylene (PP, 17%), polyethylene (PE, 13), polyamide (PA, 7%) and polyvinyl chloride (PVC, 3%). PS, PET, and PP represent most of the MPs polymer types discovered in indoor dust samples from various locations. These polymers are frequently used in fabrics, furniture, carpets, packaging, and synthetic fibers. Statistical analysis was performed on the results using Excel 2019. The results showed that there were statistically significant differences in each site with the other sites, except between (schools and mosques), (pharmacies, and medical clinics). The similarity between these sites in terms of people’s activity or in terms of furniture, the lack of carpets and curtains could explain the insignificant difference.

3

Natural Dyeing with Madder: Exploring Traditional Techniques and Color Characteristics

Tian Guangguo, Cui Rrongrong, Liu Chuanlan, Hu Xiaorui

Fibres & Textiles in Eastern Europe

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2023

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Vol. 31, no. 4

10--21

EN

The color red has a significant presence in cultures around the world. The organic dye madder, derived from plants, has been used throughout human civilization and remains an important natural dye. The research reviews five traditional madder dyeing techniques from China, Europe, Turkey, and Japan. The techniques are applied to cotton, linen, silk, and wool fabrics, and their similarities and differences are compared and analyzed. Additionally, the environmental sustainability, resource conservation, and process efficiency of these dyeing techniques are also evaluated in this article. The chromatic value of dyed textile color was tested by means of an American Hunterlab spectrophotometer, the influence of different dyeing techniques on textile color characteristics was analyzed, and the artistic features of textile color were analyzed from the perspective of visual art.

4

Czerń w architekturze w aspekcie zrównoważonego rozwoju - Część 2

Gerlic Krzysztof

Builder

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2023

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R.27, nr 5

26--32

PL

W artykule przedstawiono wyniki badań dotyczących stosowania materiałów budowlanych o ciemnych barwach oraz ich wpływu na środowisko zbudowane. W tej części przedstawione są wyniki pomiarów kamerą termowizyjną w przestrzeni otwartej, w której materiały wyeksponowane są na promieniowanie słoneczne. Analizowane przykłady zostały podzielone na trzy grupy: nawierzchnie placów i ciągów komunikacyjnych, elewacje budynków oraz materiały pokryć dachowych.

EN

The article presents the results of research on the use of dark-colored building materials and their impact on the built environment. This section presents the results of measurements with a thermal imaging camera in an open space, in which materials are exposed to solar radiation. The analyzed examples were divided into cladding materials of the façade, roofing and pavements of communication routes.

5

The Influence of Operational Exposure on Changes in Parameters of Effective Camouflage of Coatings Used in Military Technology

Michalski Marek, Pisarek Uszula, Radek Norbert, Przybył Wojciech, Szczepaniak Marcin

Advances in Science and Technology. Research Journal

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2023

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Vol. 17, no 1

182--196

EN

The paper presents an assessment of the effect of artificial aging conditions on the properties of varnish coating systems used for effective masking of military equipment and the service life of this type of coating protections was determined. As part of the research, operational exposures were simulated in the form of: accelerated corrosion tests in an artificial atmosphere in accordance with PN-EN ISO 12944-6, a continuous condensation environment at elevated temperature in accordance with the PN-EN ISO 6270-2 standard and short-term temperature impact up to 250 °C. The evaluation of the properties was carried out on the basis of measurements of the surface geometric structure and adhesion by the peel-off method. On the other hand, measurements of specular gloss, color in the range of 400-700 nm and reflectance in the range of 350-1200 nm were made in relation to the requirements of the Polish Defence Standard NO-80-A200. The operational durability of the paint coatings was assessed in terms of damage in accordance with PN-EN-ISO 4628.

6

Modification of the colour of dessert strawberries subjected to pulse electric field

Gałązka-Czarnecka Ilona, Korzeniewska Ewa

Przegląd Elektrotechniczny

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2022

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R. 98, nr 12

298--301

EN

The article presents the results of the impact of the pulsed electric field (PEF) on the modification of strawberry colour. The study concerned dessert strawberries. The electric field intensity of 5 kV/cm and 10 kV/cm was used. The CIELab system was used to assess the colour. It was shown that at the intensity of 5 kV/cm, the red component in the colour of the fruit increased by 19% in relation to the fruit not treated with PEF. This is important in the context of the content of the health-promoting anthocyanin pigments of pelargodnidin-3-glucosides, which give strawberries a red colour. The modification of strawberries with the use of an electric field also reduced the brightness of the color by 16.1%.

PL

W artykule zaprezentowano wyniki wpływu działania impulsowego pola elektrycznego (PEF) na modyfikację barwy truskawek. Badanie dotyczyło truskawek deserowych. Zastosowano pole o natężeniu 5 kV/cm i 10 kV/cm. W celu oceny barwy wykorzystano system CIELab. Wykazano, że przy natężeniu 5 kV/cm zwiększyła się składowa czerwona w barwie owoców o 19% w stosunku do owoców nie poddawanych działaniu PEF. Ma to znaczenie w kontekście zawartości prozdrowotnych barwników antocyjanowych 3-glukozydów pelargodnidyny, które nadają czerwoną barwę truskawkom. Modyfikacja truskawek z wykorzystaniem pola elektrycznego spowodowała także zmniejszenie jasności koloru o 16,1%

7

Influence of Laboratory Ageing on the Preservation of Anti-graffiti Properties for Paint Systems Used in Rolling Stock

Garbacz Marcin

Problemy Kolejnictwa

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2022

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Z. 195

97--116

EN

The article describes and presents the influence of selected ageing mechanisms of paint systems currently used in railways in Poland in the context of maintaining their original protective properties against graffiti. Six paint systems with different types of finish, which had anti-graffiti properties, were tested, and the characteristics of the surface of the paint system, such as gloss and colour, were determined after a series of painting and cleaning of graffiti (markers and sprays). The tested objects were subjected to artificial simulated ageing using laboratory solar radiation in a synergistic combination of temperature and humidity in accordance with PN-EN ISO 16474-2 and in accordance with the proprietary methodology described in DN 001/08/A2/16 section 4.1.8 using the UV-C radiation source (discrete spectrum). The tested samples were also subjected to a different type of ageing mechanism under strong corrosive conditions in the form of neutral salt spray according to the methodology described in PN-EN ISO 9227.

8

Influence of an Increased Controlled Dose of Irradiance on the Change of Selected Physicochemical Properties of Paint Systems Used in Rolling Stock

Garbacz Marcin

Problemy Kolejnictwa

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2022

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Z. 197

99--115

EN

The article presents the results of ageing tests with the use of laboratory light radiation tested according to the EN ISO 16474-2 standard for painting systems used in rolling stock. The influence of aging on such properties as gloss, colour and hardness, was determined using two different irradiance settings of the order of 60 W/m2 and 120 W/m2 for the wavelength 300÷400 nm and the same levels of radiant exposure. In addition, this study describes the most important information about laboratory aging tests with simulation of sunlight, temperature, moisture including rain, which are included in ISO standardised test methods. The influence of weather parameters has been described, in particular the influence of an increased dose of irradiance on the degradation of selected physicochemical properties of coatings and the possibility of the predicted ageing progress (changes in selected properties). The obtained results of laboratory tests allow to make certain assumptions regarding the increase of the dose of irradiance and thus the shortening of the laboratory testing time in the context of the assessment of the most desirable properties of the coating for a given application with the use of laboratory ageing tests.

9

Vegetable Waste in Freezing Process as a High Quality Material for Freeze-Drying ®

Ciurzyńska Agnieszka, Rybak Katarzyna, Karwacka Magdalena, Galus Sabina, Janowicz Monika

Postępy Techniki Przetwórstwa Spożywczego

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2022

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nr 1

91--104

EN

The article of the study was to investigate selected physical and chemical properties of freeze-dried vegetables which were rejected as a waste of freezing process due to non-compliance with the size criterion. Cauliflower, carrot, yellow bean, potato and onion were freeze-dried with registration of drying kinetics and next sugars, anthocyanin and polyphenols content were determined, rehydration and sorption properties as well as colour, water activity and content and thermal properties. It was shown that obtained samples were characterized typical properties for freeze-dried vegetables and may be used as an e.g. component of freeze-dried vegetable mix or innovative food product.

PL

Celem artykułu było przedstawienie zbadanych wybranych właściwości fizykochemicznych warzyw liofilizowanych, które zostały odrzucone jako odpad z procesu mrożenia z powodu niespełnienia kryterium wielkości. Liofilizowano kalafior, marchew, żółtą fasolę, ziemniak i cebulę z rejestracją kinetyki suszenia, a następnie oznaczono zawartość cukrów, antocyjanów i polifenoli, właściwości rehydratacyjne i sorpcyjne, a także barwę, aktywność wody oraz zawartość i właściwości termiczne. Wykazano, że otrzymane próbki charakteryzowały się właściwościami typowymi dla warzyw liofilizowanych i mogą być wykorzystywane m.in. jako składnik liofilizowanej mieszanki warzywnej lub innowacyjnego produktu spożywczego.

10

Wpływ koloru pokrycia na funkcjonowanie dachu

Patoka Krzysztof

Materiały Budowlane

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2022

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nr 11

214--215

11

Siła geometrii, redukcji i barwy. Osiedle TBS w katowickiej dzielnicy Giszowiec

Radwański Damian

Builder

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2022

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R.26, nr 8

42--45

PL

Podstawowym celem pracy jest kontestacja rozpowszechnianego i utrwalanego przekonania wskazującego, że opracowanie rozwiązania architektonicznego o wysokich walorach użytkowych i estetycznych w ramach programu TBS jest mało prawdopodobne. Postawiona w pracy hipoteza zakłada, że realizacja taniego budownictwa wielorodzinnego noszącego znamiona rozwiązania o wysokiej jakości jest możliwa wówczas, gdy przyjęta strategia projektowa odwołuje się do syntezy odpowiednio dobranych paradygmatów modernizmu. Przyjęta w pracy metodyka polega na kreatywnej i konsekwentnie ukierunkowanej korelacji odpowiednich warstw autorskiego rozwiązania architektonicznego ze wskazanymi poglądami wybitnych twórców. Ostatecznym rezultatem założeń wstępnych jest architektoniczny projekt koncepcyjny zespołu mieszkaniowego, w którym wysoka jakość rozwiązań jest pochodną strategii projektowej zakorzenionej w ponadczasowych tezach modernizmu. Najważniejszym wnioskiem z przeprowadzonej analizy jest przekonanie, że w ramach programu TBS, którego pryncypia są podporządkowane kryteriom niskich kosztów realizacji inwestycji, istnieją realne możliwości kreowania rozwiązań architektonicznych o wysokich walorach użytkowych i estetycznych.

EN

The primary purpose of this study is to contest the constantly spread and established belief indicating that the development of an architectural solution of high functional and aesthetic values within a TBS program is unlikely. The hypothesis posed in the paper assumes that the implementation of low-cost, high-quality multifamily housing is possible when the assumed project strategy is inspired by a synthesis of selected paradigms of modernism. The methodology adopted in the study is based on a creative, consistent and author-oriented correlation of the relevant layers of the author's architectural solution with the indicated views of prominent architects. The final result of the preliminary assumptions is the architectural conceptual design of a residential complex in which the high quality of the solutions is a derivative of a design strategy based on the proven, constantly up-to-date and timeless canons of modernism. The most important conclusion from the analysis is the idea that within the TBS programme, whose principles are subordinated to the criteria of low investment implementation costs, there are real possibilities of creating architectural solutions of high utility and aesthetic values.

12

Czerń w architekturze w aspekcie zrównoważonego rozwoju - Część 1

Gerlic Krzysztof

Builder

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2022

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R.26, nr 3

18--21

PL

Artykuł jest wprowadzeniem do badań dotyczących wpływu zastosowania materiałów budowlanych o ciemnych barwach w architekturze. Obecnie projektowanie architektoniczne kieruje się m.in. doktryną zrównoważonego rozwoju. Troska o zmiany klimatyczne zaleca kształtowanie środowiska zbudowanego tak, aby zapewnić najlepsze warunki dla osób przebywających w nim obecnie i w przyszłości. Badania środowiskowe potwierdzają wpływ materiałów budowlanych na mikroklimat przestrzeni zbudowanej i dlatego stanowią inspirację do analizy ich właściwości, a zwłaszcza współczynników odbicia i pochłaniania promieniowania słonecznego. Istotne jest również, dlaczego podejmowane są decyzje o stosowaniu bardzo ciemnych materiałów. Czy kreacja twórcy może to pomijać?

EN

The article is an introduction to research on the influence of the use of dark-colored building materials in architecture. Currently, architectural design is guided, among others, by the doctrine of sustainable development. Concern for climate change recommends shaping the built environment to provide the best conditions for people living now and in the future. Environmental research confirms the influence of building materials on the microclimate of the built space, hence the analysis of their properties, in particular the reflectivity and absorption of solar radiation. It is also important why decisions are made to use very dark materials. Can the designer creation skip this?

13

Colour as an element ordering the common space in educational buildings. On the example of Maria Dąbrowska Primary School No. 1 in Wrocław

Netczuk-Pol Ewa

Architectus

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2022

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Nr 2 (70)

95--103

EN

The article discusses general issues related to creating the space of educational objects in terms of colour. The perception of school space is influenced by many factors such as light, temperature, air quality, space flexibility, sense of belonging, space complexity and colour. The latter plays an important role in the perception of rooms and influences human behaviour, because apart from sound and smell, it is one of the most important stimuli perceived by our brain. Nevertheless, most of the existing schools in Poland which were built up to 1990 do not take into account colour as a factor influencing student behaviour. This issue has only recently received attention. This article presents a case study of Maria's Dąbrowska Primary School No. 1 in Wrocław. For the needs of this school, as part of the "Constructing Cultural Educational Space" program organized by Wrocław Contemporary Museum, a project was prepared to introduce colour into the interior while maintaining the historical character and substance of the object and taking into account the influence of colour on the child’s psyche. The presented interior rearrangement project may become the beginning of further research on the issue of colour and its role in shaping educational spaces.

PL

W artykule zostały omówione ogólne zagadnienia dotyczące kreowania przestrzeni obiektów edukacyjnych pod względem kolorystycznym. Na odbiór przestrzeni szkoły wpływa wiele czynników takich jak światło, temperatura, jakość powietrza, elastyczność przestrzeni, poczucie przynależności, kompleksowość miejsca i kolor. Ten ostatni odgrywa istotną rolę w odbiorze pomieszczeń i wpływa na zachowania człowieka, ponieważ jest oprócz dźwięku i zapachu jednym z ważniejszych bodźców odbieranych przez nasz mózg. Mimo to większość z obecnie istniejących we Polsce szkół wybudowanych do 1990 r. nie uwzględnia koloru jako czynnika wpływającego na zachowanie ucznia. Dopiero od niedawna zwraca się uwagę na tę kwestię. W niniejszym artykule przedstawiono studium przypadku Szkoły Podstawowej nr 1 im. Marii Dąbrowskiej we Wrocławiu. Na potrzeby tej właśnie szkoły w ramach programu „Konstruowanie Kulturalnej Przestrzeni Edukacyjnej” organizowanego przez wrocławskie Muzeum Współczesne przygotowano projekt wprowadzenia koloru do wnętrza z zachowaniem historycznego charakteru oraz zabytkowej substancji obiektu i przy uwzględnieniu wpływu koloru na psychikę dziecka. Zaprezentowany projekt przearanżowania wnętrza może stać się początkiem dalszych badań nad zagadnieniem koloru i jego roli w kształtowaniu przestrzeni edukacyjnych.

14

Reducing Steaming Times in the Printing of Nylon/Elastane Blend Fabrics via Chemical Modification

Atav Riza, Yüksel Muhammed Fatih, Yakin İsmail

Fibres & Textiles in Eastern Europe

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2021

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Vol. 29, no. 1 (145)

81--85

EN

Nylon fibres are commonly used in blends with elastane. One of the problems encountered in the printing of nylon/elastane blend fabrics is the necessity of long steaming times for fixation, which causes an increase in energy consumption. In this study, the possibility of printing polyamide fabrics with 1:2 metal complex dyes for short steaming times was investigated. For this aim, laboratory and sample scale trials were performed to develop a method of chemically modifying fibres so that polyamide fabrics can be printed in short steaming times. Based on the results obtained in both trials, it was noticed that the steaming time for fixation could be reduced from 30 minutes to 15 minutes by printing with 1:2 metal complex dyes without causing a loss of printing yield and without affecting the fastness adversly in case of applying cationisation pretreatment with a modified quaternary polyalkylamine compound based product.

PL

Włókna nylonowe są powszechnie stosowane w mieszankach z elastanem. Jednym z problemów napotykanych przy drukowaniu tkanin z mieszanki nylon/elastan są długie czasy parowania podczas drukowania, które powodują wzrost zużycia energii. W pracy zbadano możliwość drukowania na tkaninach poliamidowych barwnikami metalokompleksowymi 1:2 dla krótkich czasów parowania. W tym celu przeprowadzono próby laboratoryjne i produkcyjne. Opracowano metodę modyfikacji chemicznej włókien, tak aby tkaniny poliamidowe mogły być drukowane w krótkim czasie parowania. Na podstawie wyników uzyskanych w obu próbach zauważono, że czas naparowywania, utrwalania można skrócić z 30 do 15 minut. Pożądany efekt uzyskano drukując z użyciem barwników metalokompleksowych 1:2 z zastosowaniem obróbki wstępnej kationizacyjnej produktem na bazie modyfikowanego czwartorzędowego związku polialkiloaminy. Skrócenie czasu parowania nie powoduje utraty wydajności drukowania i nie ma negatywnego wpływu na trwałość druku.

15

Effect of Industrial Washing and Laundering on the Colour Values of Knitted Denim

Mezarcıöz Serin

Fibres & Textiles in Eastern Europe

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2021

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Vol. 29, no. 6 (150)

65--71

EN

One of the most distinctive features of denim is that the warp yarn is dyed with indigo dye and the weft yarns are not dyed, i.e. white. Although warp yarns dyed with indigo dye are woven with different woven fabric weaves, classical denim fabrics weave are produced with 3/1 Z twill weave. The search for new products in denim has led businesses to produce denim-looking knitted fabrics. Denim-looking knitted garments are subjected to industrial washing at the production phase and repetitive household washing processes in daily life. Repeated washing and drying processes cause changes that can affect user satisfaction in terms of losing the colour of the fabric. Therefore, in this study, the colour values of knitted denim fabrics produced as an alternative to denim fabrics manufactured by traditional methods after various industrial (rinse, enzyme and stone washing) and home washes (5, 10, 20 times) were examined. For this, the CIELab colour system was taken as the basis for colour analysis on a spectrophotometer device. As a result of the washing processes performed on each fabric sample (household washing and rinse, enzyme, stone washing applications), it was observed that there were differences in colour values depending on the fibre type, loop yarn length, fabric construction and washing process.

16

Effect of accelerated ageing on some surface properties of UV-coated hackberry (Celtis australis L.) wood parquet

Ayata Ümit, Esteves Bruno, Gürleyen Levent, Çakicier Nevzat, Ferreira Jose, Domingos Idalina, Türk Mutlu

Drewno : prace naukowe, doniesienia, komunikaty

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2021

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vol. 64, nr 208

17--33

EN

The importance of UV-curable coatings is currently increasing. In the parquet industry, where UV systems are applied, it is beneficial to investigate new tree species as potential raw materials. This study was carried out to determine the effect of accelerated ageing on some surface properties of hackberry (Celtis australis L.) wood treated with UV system parquet varnish. UV system parquet varnishes were applied to hackberry wood surfaces in three and five layers, according to the requirements of industrial applications. The varnished surfaces were then exposed to UV rays for 252 and 504 h using UVA-340 lamps in a QUV ageing device. Glossiness, colour parameters, pendulum hardness and adhesion strength (pull-off) (MPa) were determined for the coated samples before and after ageing, and the results for the aged and unaged test samples were compared. Analysis of variance showed that the results were significant for all tests. The results for all tests varied by ageing time.

17

Mode for hot air drying of alder blanks that retain the colour acquired during the steaming process

Dzurenda Ladislav

Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology

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2021

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No. 114

86--91

EN

Mode for hot air drying of alder blanks that retain the colour acquired during the steaming process. The paper presents a hot-air mode for drying steamed alder in the form of blanks with dimensions: 38x100x800 mm from the initial moisture content W1 ≈ 50 % to the final moisture content W2 = 10%, while maintaining the colour of wood obtained in the process of steaming with saturated water steam. The drying process is divided into two parts: (I) evaporation of free water from wet wood at drying medium temperatures td = 35 - 40 °C and relative air humidity φ = 70 – 60%, when there are no chemical changes in the lignin-saccharide complex of alder wood manifested by a change in colour; (II) evaporation of bound water from alder wood below the hygroscopicity limit is performed at temperatures td = 60 - 80 °C. The color coordinates of steamed alder wood after drying by a given mode in the CIE L* a* b* colour space are: L* = 62.5 ± 1.7; a* = 13.1 ± 0.8; b* = 18.5 ± 0.9. Total colour difference ∆E = 1.6. According to the categorization of wood color changes in thermal processes of wood , this change belongs to small (insignificant) color changes.

PL

Proces suszenia gorącym powietrzem półfabrykatów olchowych pozwalający na zachowanie barwy uzyskanej podczas procesu parowania. W pracy przedstawiono tryb suszenia gorącym powietrzem parzonych półfabrykatów olchowych o wymiarach 38x100x800 mm od wilgotności początkowej W1 ≈ 50% do wilgotności końcowej W2 = 10%. Proces suszenia był prowadzony w sposób mający na celu zachowanie barwy drewna uzyskanego w procesie obróbki hydrotermicznej w środowisku nasyconej pary wodnej. Proces suszenia składał się z dwóch etapów. Etap pierwszy obejmował odparowanie wolnej wody z mokrego drewna przy temperaturach schnącego medium td = 35 - 40°C i wilgotności względnej powietrza φ = 70 - 60%. Przy tych parametrach w kompleksie ligninowo-sacharydowym drewna olchowego nie zachodzą zmiany chemiczne objawiające się zmianą barwy. Etap drugi obejmował odparowanie wody związanej z drewna olchowego poniżej granicy higroskopijności, w temperaturach td = 60 - 80°C. Współrzędne barwy drewna olchowego parzonego po wysuszeniu przedstawioną metodą, w przestrzeni barw CIE L * a * b * wynoszą: L* = 62,5 ± 1,7; a* = 13,1 ± 0,8; b* = 18,5 ± 0,9. Całkowita zmiana barwy ∆E = 1,6. Zgodnie z kategoryzacją zmian barwy drewna w procesach termicznych, zmiana ta jest niewielka (nieznaczna).

18

Colour stability of surface finishes on thermally modified beech wood

Slabejova Gabriela, Šmidriakowá Maria

Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology

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2021

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No. 114

116--124

EN

Colour stability of surface finishes on thermally modified beech wood. The paper deals with the influence of the type of transparent surface finish on the change of colour of the surfaces of native beech wood and thermally modified wood. At the same time, the colour stability of three surface finishes on the surfaces of native and thermally modified beech wood was monitored. Beech wood was thermally modified at temperature of 125 °C for 6 hours. The thermal treatment was performed in a pressure autoclave APDZ 240, by the company Sundermann s.r.o in Banská Štiavnica. Three various types of surface finishes (synthetic, wax-oil, water-based) were applied onto the wood surfaces. The colour of the surfaces of native wood and thermally modified wood was measured in the system CIELab before and after surface finishing; the coordinates L*, a*, b*, C*ab and h*ab were measured. From the coordinates measured before and after surface finishing, the differences were calculated and then the colour difference ΔE* was calculated. Subsequently, the test specimens with the surface finishes were exposed to natural sunlight, behind glass in the interior for 60 days. The surface colour was measured at specified time of the exposure (10, 20, 30, 60 days). The results showed that the colour of the wood surfaces changed after application of the individual surface finishes; and the colour difference reached a change visible with a medium quality filter up to a high colour difference. The wax-oil surface finish caused a high colour difference on native wood and on thermally modified wood as well. On native beech wood, the lowest colour difference after exposure to sunlight was noticeable on the synthetic surface finish. On the surface of wood thermally modified, after exposure to sunlight, the lowest colour difference was noticeable on the surface with no surface finish.

19

Smartphone-Based Color Measurement of Tooth Shade Guide in Clinical Lighting Conditions

Radziun Agnieszka, Doniec Rafał, Sieciński Szymon, Piaseczna Natalia, Mocny-Pachońska Katarzyna, Cieślik-Wegemund Marta, Duraj Konrad, Tanasiewicz Marta, Tkacz Ewaryst

Annals of Computer Science and Information Systems

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2021

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Vol. 25

409--413

EN

Caries is a common disease of hard tissues of teeth which results in dental cavities, which are usually replaced by dental filling. Matching the color of a dental filling is usually a subjective assessment. In this study we conducted a color analysis of GC Gradia Direct shade guide in the lighting conditions of the dental office. Color measurement was performed using Color Grab mobile app and the results were acquired as values of RGB and HSV values. The results indicate the possibility of identifying each shade of tooth by the most prominent changes in RGB, and/or HSV components.

20

Influence of thermal treatment on selected properties of chestnut wood and full range of its visual features

Lo Monaco Angela, Pelosi Claudia, Agresti Giorgia, Picchio Rodolfo, Rubino Gianluca

Drewno : prace naukowe, doniesienia, komunikaty

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2020

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vol. 63, nr 205

5--24

EN

The use of chestnut wood (Castanea sativa Mill.) is highly relevant in Central Italy, as it is one of the most important and abundant broad-leaf species in this geographical area. The comprehension of the modifications induced by thermal treatment is of crucial importance to define the optimal temperature that could improve the mechanical and physical properties without affecting significantly the visual appearance. In this paper a careful and complete investigation on the effect of thermal treatment on chestnut wood (Castanea sativa Mill.) is reported. The aim of this study is addressed to understand the chemical-physical modifications occurred on the surface of wood samples, as a consequence of heating, in order to choose the most suitable temperature of treatment, also in the view of applying a possible coating. No such complete and homogeneous study on chestnut wood was found in the literature, so this paper contributes to add relevant scientific and technological information on it. Samples of chestnut were thermally treated 6 hours in a conventional oven at 140°C, 170°C and 200°C. Surface properties of heated wood, in comparison with untreated, were evaluated through the measurements of: roughness, colour, Vickers and Brinell hardness, surface profile and contact angle. The behaviour of earlywood and latewood was evaluated by studying separately the effect of heating on contact angle and surface micro- -hardness. Fourier transform infrared spectroscopy was also used to evaluate the chemical modification of wood components due to thermal treatment. Heating at 140°C has little influence on wood characteristics whereas 200°C has a great impact on colour, mechanical properties and hydrophobicity behaviour. The intermediate temperature, i.e. 170°C, seems to give the best results in term of improved mechanical properties and also aesthetical appearance of wood surfaces.