Wyniki wyszukiwania - BazTech

1

Badania termiczne wierzby energetycznej

Kijo-Kleczkowska Agnieszka, Gnatowski Adam, Gajek Marcin, Szumera Magdalena

Rynek Energii

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2023

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Nr 2

60--66

PL

Z uwagi na ogólnoświatową sytuację energetyczną, a także coraz bardziej restrykcyjne regulacje prawne dotyczące ochrony środowiska i emisji zanieczyszczeń do atmosfery, niezwykle ważne jest coraz intensywniejsze wdrażanie odnawialnych źródeł energii (OZE). Istotnym staje się zatem ciągłe rozpoznawanie zachowania różnego rodzaju biomasy w procesach termicznych. W niniejszej pracy autorzy przedstawili analizę badań termicznych TG/DTG/DSC/EGA dla wierzby energetycznej (Salix viminalis L.).

EN

Due to the global energy situation and increasingly restrictive lega! regulations regarding environmental protectton andem1ss1on of pollutants to the atrnosphere, it is extremely important to implement renewable energy sources (RES) more and mare intensively. 1t is important to constantly recognize the behavior of vańous types of biomass in thennal processes. In th1s paper, the authors presented the thermal analysis TG/DTG/DSC/QMS for energy wi I low (Sal ix viminalis L.).

2

Temperature Distribution Analysis on the Surface of the Radiator: Infrared Camera and Thermocouples Results Comparison

Kotrys-Działak Dagmara, Stokowiec Katarzyna

Rocznik Ochrona Środowiska

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2023

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Tom 25

37--44

EN

The experiments conducted in a didactic laboratory of the Kielce University of Technology involved temperature distribution measurements on the outer surface of a steel radiator using a thermal imaging camera and thermocouples to compare both investigation methods. The research included registering the parameters for a specific period for each of the four different medium flows. Graphs present the results with the division of the radiator into eight thermal fields. The results present the differences in temperatures between 1.78°C to 3.65°C. The non-contact method with an infrared camera seems more accurate since it is precise for surface temperature measurement.

3

Eliminacja węgla z koncentratu miedzi w piecu fluidalnym

Urbaniak Roksana, Hadała Beata, Magiera Anna, Olejnik Anna

Przemysł Chemiczny

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2023

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T. 102, nr 7

707--713

PL

Technologia prażenia koncentratów jest ściśle związana z produkcją miedzi i jest prowadzona w piecu ze złożem fluidalnym. Materiał wsadowy do pieca jest jednocześnie metalonośny i energetyczny ze względu na zawarte w nim związki węgla organicznego oraz siarczki. Prażenie koncentratów ma na celu eliminację węgla organicznego oraz konwersję siarki z formy siarczkowej na siarczanową. W pracy przedstawiono wyniki badań przeprowadzanych z wykorzystaniem analizy termicznej metodami TG, DTG i DSC, dokonano identyfikacji zakresu występowania zachodzących przemian i zmian masy podczas procesu prażenia wraz ze składem fazowym produktu. Stwierdzono, że możliwe jest skuteczne usuwanie węgla w procesie przemysłowym w zakresie temp. 650-750°C z jednoczesnym prażeniem siarczanującym.

EN

The Cu-bearing concentrates were analyzed for TG, DGT, and DSC thermal anal. Mass changes, both phase and chem. transitions and temp. ranges in which they occurred were identified. It was possible to successfully remove C from Cu concentrates during industrial process run in temp. range 650-750 ̊C and also simultaneously performed sulfating roasting.

4

Analiza termiczna wybranych inicjujących materiałów wybuchowych

Pniewski Wawrzyniec, Mazur Izabela, Borkowski Jacek

Problemy Techniki Uzbrojenia

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2023

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R. 52, z. 166

7--29

PL

W artykule przedstawiono podstawowe informacje o wybranych inicjujących materiałach wybuchowych, powszechnie stosowanych w środkach bojowych. Szczególną uwagę skupiono na właściwościach termicznych takich związków jak piorunian rtęci, tetrazen, azydek ołowiu, trójnitrorezorcynian ołowiu (TNRPb). Znajomość właściwości termicznych ww. inicjujących materiałów wybuchowych, pozwala na ich bezpieczne zastosowanie. Właściwości termiczne zostały zbadane z zastosowaniem technik DSC (różnicowa kalorymetria skaningowa) i TGA (analiza termograwimetryczna). Otrzymane wyniki potwierdzają, iż analiza termiczna (DSC i TGA) jest szybką i bezpieczną metodą pozwalającą badać właściwości termiczne inicjujących materiałów wybuchowych, jak i pozostałych materiałów wysokoenergetycznych.

EN

The article presents basic information about selected primary explosives commonly used in warfare agents. Special attention was focused on the thermal properties of such compounds as mercury fulminate, tetrazene, lead azide, lead trinitroresorcinate. Knowledge of the thermal properties of the above-mentioned primary explosives, allows their safe use. Thermal properties have been studied by using DSC (differential scanning calorimetry) and TGA (thermogravimetric analysis) techniques. The results obtained con-firm that thermal analysis (DSC and TGA) is a fast and safe method to study the thermal properties of primary explosives as well as other high-energy materials.

5

Crystal-to-crystal investigations of highly thermally stable three-dimensional coordination polymer based on sodium(I) ions and 4,4’-stilbenedicarboxylic acid

Groszek Marcin, Łyszczek Renata, Ostasz Agnieszka, Vlasyuk Dmytro

Physicochemical Problems of Mineral Processing

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2023

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Vol. 59, iss. 4

art. no. 172683

EN

The new three-dimensional coordination polymer termed {[Na2SDC(H2O)]} n (SDC2-= C16H10O42-) has been synthesized using workstation Easymax 102 while controlling the conditions and monitoring in-situ reagents. The metal complex was obtained in the reaction of sodium hydroxide with a suspension of 4,4’-stilbenedicarboxylic acid in aqueous medium. The compound was characterized by elemental analysis, single crystal, and powder X-ray diffraction methods, ATR-FTIR spectroscopy, SEM and optical microscopy, TG-DSC and TG-FTIR thermal analysis in air and nitrogen atmosphere. In the crystal structure of {[Na2SDC(H2O)]} n appears penta- and hexacoordinated sodium atoms joined by octa- and decadentate SDC2- linkers. Aqua ligand acts as bridge between Na1 and Na2 atoms. The as-synthesized sodium complex is thermally stable up to 86°C whereas its dehydrated form has extreme stability up to 491°C. Removal of water molecule leads to the crystal-to-crystal transformation yielded changes in coordination modes of COO groups. Reversibility of the hydration process in the studied complex was also examined.

6

Drewniane budownictwo modułowe jako innowacyjne rozwiązanie szkół przyszłości

Kram Dorota, Nowak Katarzyna, Śliwa-Wieczorek Klaudia, Hrehorowicz-Gaber Hanna, Blazy Rafał, Hrehorowicz-Nowak Alicja, Błachut Jakub, Łysień Mariusz, Ciepiela Agnieszka, Dudek Jerzy

Materiały Budowlane

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2023

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nr 12

27--32

PL

W artykule dokonano przeglądu i oceny dostępnych rozwiązań konstrukcyjnych oraz wybranych zagadnień fizyki budowli dotyczących budownictwa modułowego realizowanego na bazie drewna, które wpisuje się w trendy budownictwa zrównoważonego. Przedstawiono innowacyjną metodę łączenia elementów za pomocą poliuretanowych złączy podatnych (PZP), zdolnych do przenoszenia obciążeń i dużych deformacji z zachowaniem ich szczelności, która dodatkowo pozwala na demontaż konstrukcji. Porównano wartości współczynnika przenikania ciepła U [W/m2K] zewnętrznej pionowej przegrody modułu z drewna w zależności od zastosowanego rozwiązania.

EN

The article reviews and evaluates available construction solutions and selected building physics issues for modular construction based on wood, which meets the trends of sustainable construction. An innovative method of connecting elements using Polyurethane Flexible Joints (PZP) is presented, capable of carrying loads and large deformations while maintaining their tightness, which additionally allows for the disassembly of the structure. The values of the heat transfer coefficient U [W/m2K] were compared for the external vertical partition of the module depending on the solution used.

7

Evaluating the bioactivity of endodontic sealers with respect to their thermo-nanomechanical properties

Marica Andreea, Fritea Luminita, Banica Florin, Hulka Iosif, Rusu Gerlinde, Sinescu Cosmin, Costea Traian Octavian, Cavalu Simona

Materials Science Poland

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2023

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Vol. 41, No. 3

126--139

EN

Physico-chemical and mechanical features of endodontic sealers are essential functional properties involved in their sealing ability, osteoconductivity, and biocompatibility. Four different root canal sealers (Ceraseal, MTA Fillapex, AH Plus and Sealapex) were investigated in this study in order to evaluate the thermal and nanomechanical features in relation to their bioactivity potential. The nano-hardness values respected the descendent trend: HCeraseal >HSealapex >HMTA >HAHPlus, being influenced by the percent of the inorganic component in the samples, identified as residual mass in TGA/DTG (Thermogravimetrical Analysis/ Derivative Thermogravimetry) thermograms. Based on electrochemical measurement in SBF (Simulated Body Fluid) and surface investigations by SEM/EDX, we found that the bioactivity potential decreased in the following order: Ceraseal > MTA Fillapex >AH Plus >Sealapex. The highest bioactivity in the case of Ceraseal was evidenced in terms of apatite-like spherulites observed to cover the surface after 28 days incubation in SBF, and Ca/P ratio 1.71, along with the dynamic release and consumption of Ca2+ and PO3− in SBF. On the opposite side, lack of mineralization was noticed on the surface of Sealapex sample. Knowledge about the proper thermo-mechanical, biological and physico-chemical properties of the root canal materials is important in order to allow a correct material selection, either as premixed or two-component formulation, requiring good sealing or immediate therapeutic effect.

8

Zasady opracowywania katalogu złączy budowlanych (mostków cieplnych)

Pawłowski Krzysztof

Izolacje

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2023

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T. 28, nr 6

132--139

PL

W artykule przedstawiono zasady opracowywania kart katalogowych złączy budowlanych (mostków cieplnych) oraz przykładowe ich zastosowania.

EN

The article presents the principles of developing catalogue cards for construction joints (thermal bridges) and examples of their applications.

9

Research on low density polyethylene (LDPE), recycled by advanced thermal analysis (DSC, TG)

Siwczyk Bartosz, Schlafka Paweł, Sąsiadek Michał, Woźniak Waldemar

International Journal of Applied Mechanics and Engineering

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2023

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Vol. 28, no. 2

113--124

EN

This article presents the issue of recycling and maintaining the processing properties of materials made of plastics. For this purpose, samples from recycled, low-density, polyethylene were tested. The impact of the use of dyes and surface printing on the lifecycles of material and its quality was examined. For this purpose, an analysis was carried out using differential scanning calorimetry and thermos-gravimetry. It was found that the use of dyes may affect the quality of the material and increase the disposal costs of pre-used materials.

10

Alunogen from the sulfate efflorescence of the Stone Town Nature Reserve in Ciężkowice (the Outer Carpathian Mountains, Poland)

Marszałek Mariola, Gaweł Adam

Geology, Geophysics and Environment

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2023

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Vol. 49, no. 2

139--156

EN

Alunogen (Al2(SO4)3∙17H2O), a rare secondary mineral, has been found in the efflorescence on sandstones from the Stone Town Nature Reserve in Ciężkowice, southeastern Poland. This is probably the first find of this salt on such rocks in Poland. Alunogen forms in various geological environments, but mainly from the oxidation of pyrite and other metal sulfides in ore deposits and Al-rich Earth materials under low-pH conditions. Its crystallization at this particular site depends on a set of necessary physicochemical (pH, concentration), climatic (season, temperature, humidity), site-related (location and protection of efflorescence), and mineralogical (the presence of pyrite) conditions. This paper presents the mineralogical and geochemical characteristics of the alunogen from the Stone Town Nature Reserve (based on SEM-EDS, XRPD, EPMA and Raman spectroscopy methods) as well as of the efflorescence itself (based on XRPD and STA coupled with QMS and FTIR for the analysis of gas products). Crystals of alunogen take the shape of flakes, often with a hexagonal outline, clustered in aggregates forming a cellular network. Its calculated formula is (Al1.96Fe3+ 0.01)∑1.97(SO4)3∙17H2O (based on 12 O and 17 H2O). The unit-cell parameters refined for the triclinic space group P1 are: a = 7.423 (1) Å, b = 26.913 (5) Å, c = 6.056 (1) Å, α = 89.974 (23)°, β = 97.560 (25)°, γ = 91.910 (22)°. The Raman spectra (SO4) bands are: intensive 995 cm−1 (ν1); low-intensive 1069, 1093 and 1127 cm−1 (ν3); low-intensive 419 and 443; medium-intensive 470 cm−1 (ν2); and medium-intensive 616 cm−1 (ν4). Those at 530, 312 and at 338 cm−1 are assigned to water vibrations and those at 135, 156, 180 cm−1 to the lattice modes. Although the efflorescence contained an admixture of other minerals (pickeringite, gypsum and quartz), the predominant alunogen is almost chemically pure and the above parameters are consistent with the values reported in the literature for alunogen from different locations and of various origins.

11

Impact of thermal backfill parameters on current-carrying capacity of power cables installed in the ground

Szultka Seweryn, Czapp Stanisław, Tomaszewski Adam

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2023

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Vol. 71, nr 3

art. no. e145565

EN

Proper design of power installations with the participation of power cables buried in homogeneous and thermally well-conductive ground does not constitute a major problem. The situation changes when the ground is non-homogeneous and thermally low-conductive. In such a situation, a thermal backfill near the cables is commonly used. The optimization of thermal backfill parameters to achieve the highest possible current-carrying capacity is insufficiently described in the standards. Therefore, numerical calculations based on computational fluid dynamics could prove helpful for designers of power cable lines. This paper studies the influence of dimensions and thermal resistivity of the thermal backfill and thermal resistivity of the native soil on the current-carrying capacity of power cables buried in the ground. Numerical calculations were performed with ANSYS Fluent. As a result of the research, proposals were made on how to determine the current-carrying capacity depending on the dimensions and thermal properties of the backfill. A proprietary mathematical function is presented which makes it possible to calculate the cable current-carrying capacity correction factor when the backfill is used. The research is expected to fill the gap in the current state of knowledge included in the provisions of standards.

12

Numerical analysis of the thermal behaviour and performance of a brake system with temperature-dependent material properties

Hassan M. A., Ali M., Abdullah O. I.

Archives of Materials Science and Engineering

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2023

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Vol. 122, nr 2

58--69

EN

Purpose: The brake system is the most significant component of a vehicle because it protects the driver, passengers, other road users, and property on both sides of the road. The basic principle of the disc brake system depends on the friction-based between the brake pads and rotor disc. Design/methodology/approach: The paper introduced a developed 3D finite element thermal model of the brake system to simulate the heat generated by friction in the vehicle's disc brake. Findings: The results presented the surface temperature at any instant of the disc brake under various initial velocities when the materials properties of the rotor disc and pad depend on temperature. Research limitations/implications: The main aim of the present paper is to build a numerical model to simulate the braking process under various initial vehicle velocities and investigate the influence of the material properties when they function on temperature and constant. Originality/value: The maximum difference between the two cases (contact and depend on the temperature) was 17 K for the initial velocity of 144,120. Also, it was found out that the percentage differences of the surface temperature increasing with the rise in initial vehicle velocity were 323% and 392.5% when the initial velocity of the vehicle increased from 100 km/h to 144 km/h.

13

Influence of Charge Materials on the Metallurgical Quality of Gray Cast Iron

Dwulat Rafał, Janerka Krzysztof, Grzesiak K., Gałuszka M.

Archives of Foundry Engineering

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2023

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Vol. 23, iss. 2

66--71

EN

The article presents the influence of the percentage share of pig iron and steel scrap on the chemical composition, physicochemical and mechanical properties. Using an induction furnace, 6 melts were carried out with a variable amount of pig iron in the charge from 0 to 50%. For carburizing, a RANCO 9905 carburizer with a carbon content of 99.2% was used. After melting and introducing FeSi75, temperature measurement was carried out and the metal was superheated to 1500°C. The next step was to pour the samples for chemical analysis, DTA (Derivation Thermal Analysis) and strength and hardness from the melting furnace without inoculation. The last step was to carry out the inoculation by introducing 0.3% barium inoculant into the vat and pouring samplers for DTA analysis. The inoculation was carried out solely to determine changes in DTA parameters, mainly Temin, compared to castings without inoculation.

14

Investigation of Infrared Thermography of Cortical Bone Grinding in Neurosurgery

Babbar Atul, Jain Vivek, Gupta Dheeraj, Goyal Kapil Kumar, Prakash Chander, Saxena Kuldeep Kumar, Kumar Sandeep, Bartoszuk Marian

Advances in Science and Technology. Research Journal

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2023

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Vol. 17, no 1

116--123

EN

In this work, an effort has been made to determine the effect of different shape surgical burr on the thermogenesis during bone osteotomy. The abrasion during bone grinding leads to heat generation and subsequently rise in the temperature which may have adverse effects such as osteonecrosis, blood coagulation in the carotid artery, damage to sciatic nerves, and even loss of vision. So, mitigating the temperature rise during bone grinding is of paramount importance. Especially, in endoscopic endonasal approach (EEA) in which nasal passage is used for the inserting the grinding burr and reaching the target region. The miniature abrasion can significantly increase the temperature and hence leads to the thermal damage to nerves surrounding the temporal and frontal lobe. These parts of the brain controls movement, problem solving ability, behavior, personality mood, hearing, language, memory, speech, breathing, heart rate, consciousness etc. Furthermore, neurosurgeons rely on their personal surgical experience for estimating the temperature rise during grinding. However, this is much difficult for novice surgeons. Therefore, it becomes critically important to preserve the soft neural tissues and nerves amid bone grinding. To overcome these concerns, infrared thermography technique has been exploited to determine the possibility of thermogenesis during bone grinding by measuring the temperature rise and its distribution using infrared camera. All experiments have been carried at a constant set of process variables. The grinding zone is continuously flooded with the irrigating solution to remove the heat and bone debris away from the grinding site. It has been observed that convex tool shape generated lower maximum temperature i.e. 46.03 ℃ among all tools. The temperature produced by the convex tool is 12.06% lower than spherical tool, 33.39% lower than cylindrical tool, and 10.55% lower than tree-shape tool. The results showed that convex shape tool could prevent thermal necrosis in the bone as temperature caused (i.e. 46 ℃) was less than the threshold limit of osteonecrosis. Thermograms revealed that infrared thermography technique could be implemented for the in-vivo surgical operations for the measurement of temperature during bone grinding.

15

Thermal studies of polymer waste and coal sludge

Kijo-Kleczkowska Agnieszka, Gnatowski Adam, Kwiatkowski Dariusz, Szumera Magdalena, Madej Dominika, Leśniak Magdalena, Otwinowski Henryk

Rynek Energii

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2022

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Nr 5

89--96

EN

Plastics are widely used in various industries and households, which has an impact on the condition of the natural environment in terms of waste. Today, the leading plastics’ disposal method is landfilling. It should be emphasized that the production of electricity in Poland is based mainly on hard coal and lignite, which is associated with the continuous production of various types of waste, including post-flotation coal waste (coal sludge). That is why rational waste management, recycling, proper disposal, use, and improvement of the existing and implementation of new technological solutions are crucial for environmental protection. This study undertakes cognitive research on the possibility of using PA6 polyamide waste, marked by high calorific value. Thermal analysis techniques (DSC-TG-QMS) were applied for this purpose. The study includes a comparison of the results of tests conducted for polyamide recyclate, coal sludge, and PA6 recyclate composite with a filler constituting 5% of coal sludge.

PL

W pracy podjęto badania poznawcze nad możliwością wykorzystania odpadów poliamidowych PA6, charakteryzujących się wysoką kalorycznością. Zastosowano w tym celu techniki analizy termicznej (DSC/QMS). W pracy porównano wyniki badań przeprowadzonych dla recyklatu poliamidowego, mułu węglowego i kompozytu z recyklatu PA6 z napełniaczem stanowiącym 5% mułu węglowego.

16

Metody analizy termicznej i ich zastosowanie w badaniach wpływu dodatków na rozkład termiczny azotanu(V) amonu

Myka Agnieszka, Zdunek Anna, Rusek Piotr

Przemysł Chemiczny

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2022

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T. 101, nr 7

458--464

PL

Przedstawiono krótką charakterystykę najczęściej stosowanych metod analizy termicznej oraz możliwości pomiarowych, jakie stwarzają poszczególne metody. Omówiono również wybrane właściwości fizykochemiczne azotanu(V) amonu oraz związane z nimi zagrożenia. Na podstawie dostępnej literatury dokonano oceny i klasyfikacji związków mających różny wpływ na rozkład termiczny azotanu(V) amonu. Związki te podzielono na substancje obojętne, promujące oraz inhibitujące rozkład termiczny azotanu(V) amonu.

EN

A review, with 39 refs., of the fundamentals of the most commonly used methods of thermal anal. (TG, DTA and DSC) and the measurement possibilities offered by each method. Selected phys. chem. properties of NH₄NO₃ and associated hazards were presented. Inorg. additives used or possible to be used in a mixt. with NH₄NO₃ and their effect on the course of exothermic decompn. were discussed. Mainly materials that can enrich NH₄NO₃ with nutrients, but also other inorg. salts as well as mine and waste raw materials, were considered.

17

Tłumienie efektu thermal crosstalk w linijkach laserowych

Dąbrówka Dominika, Sarzała Robert P.

Przegląd Elektrotechniczny

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2022

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R. 98, nr 9

162--165

PL

W pracy przedstawiono wyniki termicznej analizy numerycznej matrycy azotkowych laserów o emisji krawędziowej emitujących falę 540 nm. Rozważono trzy różne rozwiązania konstrukcyjne zapewniające efektywne ograniczenie modu w rejonie obszaru czynnego emitera. Obliczenia przeprowadzono dla matryc zawierających od dwóch do dziesięciu emiterów. Wyniki pokazują, iż równomierny rozkład temperatury w poszczególnych emiterach można uzyskać bez wyrafinowanego układu sterującego, ale jedynie odpowiednio rozmieszczając emitery w matrycy.

EN

In the paper the results of a numerical thermal crosstalk analysis of 540 nm nitride-based edge-emitting lasers are presented. The work investigated three different structures that provide effectives mode reduction in the active region of the emitter. A laser array consisting of two to ten emitters was considered. The obtained results show that a uniform temperature distribution in individual emitters can be achieved without a sophisticated control system, but only by properly placing the emitters in the array.

18

Analiza termiczna dwuwymiarowych matryc laserów VCSEL

Sarzała Robert P., Poborska Julita

Przegląd Elektrotechniczny

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2022

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R. 98, nr 9

166--169

PL

W pracy przedstawiono wyniki numerycznej analizy termicznej matryc laserów GaAs VCSEL emitujących falę 850 nm. Obliczenia wykonano dla pojedynczego lasera oraz dwóch typów matryc: nieskończonej i półnieskończonej. Uwzględniono różne wielkości apertur elektrycznych, różne odległości między emiterami oraz różną gęstość źródeł ciepła. Trójwymiarowe modele rozpływu ciepła pozwoliły określić rozkłady temperatury, dolną i górną granicę rezystancji termicznej analizowanych urządzeń oraz wzajemne oddziaływanie cieplne między emiterami matryc laserowych.

EN

In this paper the results of thermal numerical analysis of 850 nm GaAs VCSEL arrays are presented. A single VCSEL emitter and two types of VCSEL arrays: infinite and semi-infinite, were modelled. Several oxide aperture diameters, several values of the distance between emitters and various heat source densities were considered. The models for 3-D heat spreading allowed us to determine the heat flow distribution and to obtain the upper and lower bounds for both thermal resistance of single emitters and thermal crosstalk in arrays.

19

Starch plasticization with choline dihydrogencitrate-based deep eutectic system

Wilpiszewska Katarzyna, Skowrońska Dorota

Polish Journal of Chemical Technology

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2022

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Vol. 24, nr 3

53--59

EN

Two-component deep eutectic solvents (DES) based on choline dihydrogencitrate and glycerol or urea were tested as starch plasticizers. Thermal analysis techniques were applied to characterize the properties of starch/DES systems. The X-ray diffractometry measurements revealed a significant decrease in crystallinity indicating that used DES exhibited the ability to penetrate the ordered regions of potato starch, which is a necessary feature of a true plasticizer. However, the differential scanning calorimetry and dynamic thermal analysis results surprisingly showed an increase of Tg of starch materials indicating chemical crosslinking at elevated temperature. The eutectic solvents based on choline dihydrogencitrate could act as a plasticizer and a simultaneously crosslinking agent.

20

Influence of sisal fibre modification on the microbial stability of poly(hydroxybutyrate-co-valerate): thermal analysis

Kittikorn Thorsak, Strömberg Emma, Ek Monica, Karlsson Sigbritt

Polimery

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2022

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Vol. 67, nr 3

93--101

EN

The effect of modification of sisal fibre with propionic anhydride and vinyltrimethoxy silane on the microbiological stability of poly(hydroxybutyrate-co-valerate) (PHBV) was investigated. The effect of the coupling agent – PHBV grafted with maleic anhydride (PHBV-g-MA) was also investigated. The best adhesion at the interface was observed for propionylation of sisal fibre, which improved the thermal properties of the composites. Composites with modified sisal fibre were characterized by higher activation energy (155 kJ/mol), which is related to stronger interactions at the matrix-fibre interface. In the microbial growth test, all biocomposites showed a decrease in molecular weight due to enzymatic degradation by Aspergillus niger. The most resistant to microorganisms was the composite containing propionylated sisal fibre. DMTA and TGA also confirmed the highest microbiological stability of the composite with the addition of propionylated sisal fibre, as evidenced by the smallest change in the properties after the microbiological growth test. In contrast, PHBV- g-MA caused significant enzymatic degradation due to the presence of large amorphous regions.

PL

Zbadano wpływ modyfikacji włókna sizalowego bezwodnikiem propionowym i winylotrimetoksy silanem na stabilność mikrobiologiczną poli(hydroksymaślanu-co-walerianianu) (PHBV). Zbadano również wpływ środka sprzęgającego − PHBV szczepionego bezwodnikiem maleinowym (PHBV-g-MA). Najlepszą adhezję na granicy faz stwierdzono w przypadku zastosowania propionylowania włókna sizalowego, co poprawiło właściwości termiczne kompozytów. Kompozyty z modyfikowanym włóknem sizalowym charakteryzowały się wyższą energią aktywacji (155 kJ/mol), co wiąże się z silniejszymi oddziaływaniami na granicy faz osnowa-włókno. W teście wzrostu drobnoustrojów wszystkie biokompozyty wykazywały zmniejszenie masy cząsteczkowej na skutek enzymatycznej degradacji przez Aspergillus niger. Najbardziej odporny na działanie mikroorganizmów były kompozyt zawierający propionylowane włókno sizalowe. DMTA i TGA potwierdziły również najwyższą stabilność mikrobiologiczną kompozytu z dodatkiem propionylowanego włókna sizalowego, o czym świadczy najmniejsza zmiana badanych właściwości po teście wzrostu mikrobiologicznego. Natomiast, PHBV-g-MA powodował znaczną degradację enzymatyczną ze względu na obecność dużych obszarów amorficznych.