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Tytuł:
Effects of different grain size of expanded perlite aggregate and content of silica aerogel on the characteristics of lightweight cementitious composite
Autorzy:
Vashchuk, Andrii
Ślosarczyk, Agnieszka
Powiązania:
https://bibliotekanauki.pl/articles/24085741.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
lightweight composite
expanded perlite aggregate
silica aerogel
mechanical characteristic
thermal conductivity coefficient
scanning electron microscopy
Opis:
In this research, an attempt was made to investigate effects of expanded perlite aggregate grain size on consistency, density, compressive strength, thermal conductivity and microstructure of 15 different composite mixes with silica aerogel. As for the samples preparation, expanded perlite aggregate of 5 different groups based on grain size, were used for sample preparation, then partially replaced by volume for 20% and 40% of hydrophobic silica aerogel particles. The results showed, that density of the samples varied between 0.35 g/cm3 and 1.5 g/cm3, flexural strength varied between 3.4 MPa and 7.4 MPa, compressive strength was in the range between 12.3 MPa and 55 MPa, thermal conductivity coefficient was in the range between 0.130 W/mK and 0.190 W/mK. Scanning electron microscopy showed that expanded perlite aggregates and silica aerogel particles are capable of being mixed and formed homogenous mixture. Nevertheless, microscope images indicated weaker adhesion of silica aerogel particles at interfacial zone as compared with expanded perlite aggregate particles. Results revealed, that both of the factors: grain size of expanded perlite aggregate particles silica aerogel content influenced the density, compressive strength and thermal conductivity. The study also indicated feasibility of expanded perlite aggregate and silica aerogel for achieving homogeneous mixture of the lightweight cementitious composites. Study demonstrated that using different size fractions of expanded perlite aggregate affects differently physical, mechanical and thermal characteristics of the lightweight cementitious composite with silica aerogel.
Źródło:
Physicochemical Problems of Mineral Processing; 2023, 59, 4; art. no. 174338
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermomodernization – Rescue for the Building
Autorzy:
Orłowska, Magdalena
Powiązania:
https://bibliotekanauki.pl/articles/27315754.pdf
Data publikacji:
2023
Wydawca:
Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:
energy saving
characteristic
thermal modernization
Opis:
The article discusses issues related to modifying existing buildings to improve their condition in terms of lower energy consumption and reducing heat loss. The study takes the form of a review. Current systems and data are described according to relevant standards. The issue of the energy efficiency of the building is explored. A list of the most common ways of thermal modernization has been presented. Financial support programs were discussed. The merits and drawbacks of the solutions are delineated.
Źródło:
Rocznik Ochrona Środowiska; 2023, 25; 208--214
1506-218X
Pojawia się w:
Rocznik Ochrona Środowiska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimization of characteristic diagram based thermal error compensation via load case dependent model updates
Autorzy:
Naumann, Christian
Glänzel, Janine
Dix, Martin
Ihlenfeldt, Steffen
Klimant, Philipp
Powiązania:
https://bibliotekanauki.pl/articles/2086271.pdf
Data publikacji:
2022
Wydawca:
Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:
thermal effect
machine tool
compensation
regression analysis
Opis:
The compensation of thermal errors in machine tools is one of the major challenges in ensuring positioning accuracy during cutting operations. There are numerous methods for both the model-based estimation of the thermal tool center point (TCP) deflection and for controlling the thermal or thermo-elastic behavior of the machine tool. One branch of thermal error estimation uses regression models to map temperature sensors directly onto the TCP-displacement. This can, e.g., be accomplished using linear models, artificial neural networks or characteristic diagrams. One of the main limitations of these models is the poor extrapolation behavior with regard to untrained load cases. This paper presents a new method for updating characteristic diagram based compensation models by combining existing models with new measurements. This allows the optimization of the compensation for serial production load cases without the effort of computing a new model. The new method was validated on a 5-axis machining center.
Źródło:
Journal of Machine Engineering; 2022, 22, 2; 43--56
1895-7595
2391-8071
Pojawia się w:
Journal of Machine Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Precision Calculations of the Characteristic Impedance of Complex Coaxial Waveguides Used in Wideband Thermal Converters of AC Voltage and Current
Autorzy:
Kubiczek, Krzysztof
Kampik, Marian
Powiązania:
https://bibliotekanauki.pl/articles/2124756.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
AC voltage standard
current shunt
characteristic impedance
multilayer cylindrical conductor
FEM simulation
modified Bessel functions
numerical stability
calorimetric thermal voltage converter
ac-dc transfer difference
Opis:
The article presents precision and numerically stable method of calculation of the characteristic impedance of cylindrical multilayer waveguides used in high-precision wideband measuring instruments and standards, especially calculable thermal converters of AC voltage and precision wideband current shunts. Most of currently existing algorithms of characteristic impedance calculation of such waveguides are based upon approximations. Unfortunately, application of such methods is limited to waveguides composed of a specific, usually low number of layers. The accuracy of approximation methods as well as the number of layers is sometimes not sufficient, especially when the coaxial waveguide is a part of precision measurement equipment. The article presents the numerically stable matrix analytical formula using exponentially scaled modified Bessel functions to compute characteristic impedance and its components of the cylindrical coaxial multilayer waveguides. Results obtained with the developed method were compared with results of simulations made using the Finite Element Method (FEM) software simulations. Very good agreement between results of those two methods were achieved.
Źródło:
International Journal of Electronics and Telecommunications; 2022, 68, 3; 527--533
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermolift oil recovery technologies stimulated with a resource-saving energy system
Technologie wydobycia ropy naftowej Thermolift, w których stosowany jest system energetyczny pozwalający na oszczędne wykorzystanie zasobów
Autorzy:
Hasanov, Ramiz
Ramazanov, Fazil
Musavi, Saida
Kazimov, Musa
Powiązania:
https://bibliotekanauki.pl/articles/31344031.pdf
Data publikacji:
2022
Wydawca:
Instytut Nafty i Gazu - Państwowy Instytut Badawczy
Tematy:
well
thermal lift
thermal activity
electrochemical generator
metric characteristic
threshold value
compatibility
electrophysical phenomena
material support
odwiert
wypór termiczny
aktywność termiczna
generator elektrochemiczny
cechy wskaźników
wartość progowa
kompatybilność
zjawiska elektrofizyczne
wsparcie materiałowe
Opis:
In this article, the creation of a thermal lift technology for oil wells through the use of installations with a solid oxide fuel cell has been discussed. The necessary calculations were carried out to determine the level of thermal activity in wells producing hydrocarbon resources of various compositions. Arrangements necessary to achieve this thermal activity based on solid oxide fuel cells (SOFCs) are proposed. SOFC metric characteristics are proposed that are compatible with their additional phenomena, namely, material support, shape, etc. The threshold value of the operating thermal characteristic of SOFCs is obtained depending on the structural and physical properties of their material support. The most effective ways for determination of the required thermobaric parameters of the fluid in accordance with the formation area and product, development of a resource-saving complex for the production of percussion fluid in accordance with these parameters, determination of processing periodicity to manage the thermobaric condition of the formation area, assessment of impact on the formation area and other factors generalise them. The purpose of the article is to develop a technology for management the thermobaric condition of the area through alternative resource-saving energy systems (development of Thermolift technology), substantiation of operational parameters and creation of surface equipment. The scientific idea of the presented article significantly increases the mobility of their hydrocarbon reserves on the basis of the thermobaric action of working agents, which are the product of a resource-saving surface complex (i.e. by providing Thermolift technology) and, finally increases the operational efficiency of production wells and, as a result, the production capacity of the reservoirs.
W niniejszym artykule omówiono powstanie technologii wyporu termicznego dla odwiertów ropnych przez zastosowanie instalacji z ogniwem paliwowym ze stałym tlenkiem. Przeprowadzono wymagane obliczenia w celu ustalenia poziomu aktywności termicznej w odwiertach eksploatujących zasoby węglowodorów o różnym składzie ropy naftowej. Zaproponowano układy niezbędne do osiągnięcia tej aktywności termicznej oparte na ogniwach paliwowych ze stałym tlenkiem (SOFC). Zaproponowano takie parametry wskaźników SOFC, które są zgodne z ich dodatkowymi cechami, takimi jak rodzaj zastosowanego materiału, kształt itd. Wartość progowa eksploatacyjnej charakterystyki termicznej SOFC uzależniona jest od właściwości strukturalnych i fizycznych zastosowanego do ich konstrukcji materiału. Związane jest to z najbardziej efektywnymi sposobami określenia wymaganych parametrów temperaturowo-ciśnieniowych eksploatowanego płynu w zależności od obszaru występowania formacji i produktu, opracowaniem bezpiecznego dla zasobów systemu produkcji płynu udarowego zgodnego z tymi parametrami, określeniem częstotliwości przetwarzania w celu zarządzania warunkami temperaturowo- ciśnieniowymi w obrębie formacji, czy też oceną oddziaływania w obszarze występowania formacji. Celem artykułu jest przedstawienie opracowanej technologii do zarządzania warunkami temperaturowo-ciśnieniowymi obszaru złoża wykorzystującej alternatywne, pozwalające na oszczędne wykorzystanie zasobów, systemy energetyczne (technologia Thermolift), wraz z uzasadnieniem parametrów eksploatacyjnych i przedstawieniem osprzętu powierzchniowego. Naukową ideą niniejszego artykułu jest znaczące zwiększenie zakresu mobilności dostępnych zasobów węglowodorów dzięki temperaturowo-ciśnieniowemu działaniu czynników roboczych będących produktem systemu powierzchniowego pozwalającego na bardziej ekonomiczne wykorzystanie zasobów (tj. poprzez dostarczenie technologii Thermolift), a finalnie – zwiększenie wydajności operacyjnej odwiertów eksploatacyjnych, prowadzące w efekcie do wzrostu wydajności produkcyjnej złóż ropy naftowej.
Źródło:
Nafta-Gaz; 2022, 78, 11; 781-800
0867-8871
Pojawia się w:
Nafta-Gaz
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of solar cooker with thermal storage for remote hilly areas: determination of heating and cooling characteristic time
Autorzy:
Raghav, Geetanjali
Sharma, Pankaj Kumar
Kumar, Suresh
Maithani, Rajesh
Iung, Alexis
Quentin, Mercier
Powiązania:
https://bibliotekanauki.pl/articles/2142896.pdf
Data publikacji:
2021
Wydawca:
Centrum Badań i Innowacji Pro-Akademia
Tematy:
solar energy
solar cookers
thermal storage
thermal performance
energia słoneczna
kuchenka słoneczna
magazynowanie ciepła
wydajność cieplna
Opis:
Solar cooking finds a major application in rural areas of Uttarakhand, India, yet its utilization is still limited due to certain limitation such as intermittent nature of solar radiations. This drawback limits solar cooker in becoming a viable alternate solution of LPG and other pollution causing resources such as wood. In order to cater this problem a numerical analysis of box type solar cooker with storage is carried out. The energy stored in the storage material will keep the cooker warm up to the time when food is consumed. Charging and discharging time analysis is performed in with an aim to understand the effect of storage on solar cooker. Heating and cooling characteristic time are being evaluated and analysed with storage. Thermal performance of box type solar cooker is measured in terms of figures of merit according to BIS standards. The effect of storage has also been analysed in terms of charging and discharging time and first figure of merit of box type solar cooker.it has been observed that during discharging the heat is stored for more duration as compared to the charging time as discharge time is approx. 4-5 hours while charging time for the same amount of insolation is around 3-4 hours.
Źródło:
Acta Innovations; 2021, 40; 5-18
2300-5599
Pojawia się w:
Acta Innovations
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Characteristic of low-density polyethylene reinforcement with nano/micro particles of carbon black: a comparative study
Autorzy:
Sabr, O.H.
Al-Mutairi, N.H.
Layla, A.Y.
Powiązania:
https://bibliotekanauki.pl/articles/2175763.pdf
Data publikacji:
2021
Wydawca:
Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Tematy:
low-density polyethylene
carbon black
thermal conductivity
nanocomposite
SEM
polietylen wysokociśnieniowy
sadza
przewodność cieplna
nanokompozyt
Opis:
Purpose: Low density polyethylene is commonly used polymer in the industry because of its unique structure and excellent overall performance. LDPE, is relatively low mechanical properties and thermal stability can sometimes limit its application in industry. Therefore, the development of particulate reinforced polymer composites is one of the highly promising methodologies in the area of next generation engineering products. Design/methodology/approach: Nano and Micro composite from low density polyethylene LDPE reinforced with different weight fraction of carbon black particles (CB) (2, 4 and 8)% prepared by first dispersion Nano and Micro carbon black particles CB in solvent and then mixing manually with low density polyethylene LDPE pellet and blended by twin-screw extruder, the current research study the mechanical properties (tensile strength, elastic modulus,and hardness), FTIR, DSC,and thermal conductivity of prepared nano and micro composites using two methodes and the morphological properties of nano-micro composites. Findings: The tensile strength of the LDPE/CB nano and micro composites improved at 2% and 4%, respectively, and decreasing at 8%, addition of carbon black nanoparticles led to increase the tensile strength of pure low-density polyethylene from 13.536 MPa to 19.71 MPa, and then dropping to 11.03 MPa at 8% percent,while the elastic modulus of LDPE/ CB nano and miro composites shows an improvement with all percentages of CB. The results show that the mechanical properties were improved by the addition carbon black nanoparticles more than addition micro- carbon black . FTIR show that physical interaction between LDPE and carbon black. The thermal conductivity improvement from 0.33 w/m.k for pur LDPE to 0.62234 w/m.k at 2% CB microparticle content and the reduced to 0.18645 w/m.k and 0.34063 w/m.k at (4 and 8)% micro-CB respectively , The thermal conductivity of LDPE-CB nano-composites is low in general than that the LDPE-CB microcomposite. DSC result show improvement in crystallization temperature Tc, melting temperature and degree of crystallization with addition nano and micro carbon black. Morever, SEM images revealed to uniform distribution and good bonding between LDPE and CB at low percentages and the precence of some agglomeration at high CB content. Research limitations/implications: This research studied the characteristics of both nano and micro composite materials prepared by two steps: mixing CB particles with solvent and then prepared by twin extruder which can be used packaging material, but the main limitation was the uniform distribution of nano and micro CB particles within the LDPE matrix. In a further study, prepare a blend from LDPE with other materials and improve the degradation of the blend that used in packaging application. Originality/value: LDPE with nanocomposites are of great interest because of their thermal stability, increased mechanical strength, stiffness, and low gas permeability, among other properties that have made them ideal for applications in the packaging and automotive industries. LDPE reinforcements nano-sized carbon black can have better mechanical and thermal properties than micron, resulting in less material being needed for a given application at a lower cost.
Źródło:
Archives of Materials Science and Engineering; 2021, 110, 2; 49--58
1897-2764
Pojawia się w:
Archives of Materials Science and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new multigrid based method for characteristic diagram based correction of thermo-elastic deformations in machine tools
Autorzy:
Naumann, Christian
Putz, Matthias
Powiązania:
https://bibliotekanauki.pl/articles/99426.pdf
Data publikacji:
2019
Wydawca:
Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:
thermal effects
algorithm
machine tool
measurement
Opis:
It is a well-known problem of milling machines, that waste heat from motors, friction effects on guides, environmental variations and the milling process itself greatly affect positioning accuracy and thus production quality. An economic and energy-efficient method of correcting this thermo-elastic positioning error is to gather sensor data (temperatures, axis positions, etc.) from the machine tool and the process and to use that information to predict and correct the resulting tool center point displacement using high dimensional characteristic diagrams. The computation of these characteristic diagrams leads to very large sparse linear systems of equations which require a vast memory and computation time to solve. This is particularly problematic for complex machines and varying production conditions which require characteristic diagrams with many input variables. To solve this issue, a new multigrid based method for the computation of characteristic diagrams will be presented, tested and compared to the previously used smoothed grid regression method.
Źródło:
Journal of Machine Engineering; 2019, 19, 4; 42-57
1895-7595
2391-8071
Pojawia się w:
Journal of Machine Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Parameterization of environmental influences by automated characteristic diagrams for the decoupled fluid and structural-mechanical simulations
Autorzy:
Glänzel, Janine
Kumar, Tharun Suresh
Naumann, Christian
Putz, Matthias
Powiązania:
https://bibliotekanauki.pl/articles/99399.pdf
Data publikacji:
2019
Wydawca:
Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:
thermal effects
simulation
machine tool
environment
positioning error
Opis:
Thermo-elastic effects contribute the most to positioning errors in machine tools especially in operations where high precision machining is involved. When a machine tool is subjected to changes in environmental influences such as ambient air temperature, velocity or direction, then flow (CFD) simulations are necessary to effectively quantify the thermal behaviour between the machine tool surface and the surrounding air (fluid). Heat transfer coefficient (HTC) values effectively represent this solid-fluid heat transfer and it serves as the boundary data for thermo-elastic simulations. Thereby, deformation results can be obtained. This two-step simulation procedure involving fluid and thermo-structural simulations is highly complex and time-consuming. A suitable alternative for the above process can be obtained by introducing a clustering algorithm (CA) and characteristic diagrams (CDs) in the workflow. CDs are continuous maps of a set of input variables onto a single output variable, which are trained using data from a limited number of CFD simulations which is optimized using the clustering technique involving genetic algorithm (GA) and radial basis function (RBF) interpolation. The parameterized environmental influences are mapped directly onto corresponding HTC values in each CD. Thus, CDs serve as look-up tables which provide boundary data (HTC values along with nodal information) under several load cases (combinations of environmental influences) for thermo-elastic simulations. Ultimately, a decoupled fluid-structural simulation system is obtained where boundary (convection) data for thermo-mechanical simulations can be directly obtained from CDs and would no longer require fluid simulations to be carried out again. Thus, a novel approach for the correction of thermo-elastic deformations on a machine tool is obtained.
Źródło:
Journal of Machine Engineering; 2019, 19, 1; 98-113
1895-7595
2391-8071
Pojawia się w:
Journal of Machine Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the selection and assessment of input variables for the characteristic diagram based correction of thermo-elastic deformations in machine tools
Autorzy:
Ihlenfeldt, S.
Naumann, C.
Putz, M.
Powiązania:
https://bibliotekanauki.pl/articles/99689.pdf
Data publikacji:
2018
Wydawca:
Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:
thermal effects
algorithm
machine tool
measurement
Opis:
It is a well-known problem of milling machines, that waste heat from motors, friction effects on guides and most importantly the milling process itself greatly affect positioning accuracy and thus production quality. An economic and energy-efficient method of correcting this thermo-elastic positioning error is to gather sensor data from the machine tool and the process and to use that information to predict and correct the resulting tool center point displacement using high dimensional characteristic diagrams. On the one hand, the selection of which and how many input variables to use in the characteristic diagrams is critical to their performance. On the other hand, however, there are often a great number of possible variable combinations available and testing them all is practically impossible. This paper will discuss the suitability of many different input variable types and present a new method of input variable selection which will be compared to existing methods and demonstrated on measurements performed on a machine tool.
Źródło:
Journal of Machine Engineering; 2018, 18, 4; 25-38
1895-7595
2391-8071
Pojawia się w:
Journal of Machine Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A study of hydraulic characteristic for borehole heat exchangers
Autorzy:
Śliwa, T.
Jaszczur, M.
Kruszewski, M.
Sapińska-Śliwa, A.
Bieda, A.
Kowalski, T.
Złotkowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/298988.pdf
Data publikacji:
2017
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
thermal response test
borehole heat exchanger
hydraulic characterization
Opis:
Thermal Response Test (TRT) is a standard test performed in borehole heat exchangers (BHE), which provides thorough understanding of thermal parameters of surrounding rock mass. Following work consists of calculations for hydraulic power and pressure losses along the BHE’s length. Analysis was carried out in eight BHE’s with different diameters, lengths and heat carriers in various areas throughout Poland. In accordance with TRT results, potential power exchanged between BHE and rock mass was determined. In order to find relations between pressure losses and volumetric flow rate, hydraulic tests in average static temperature of rock mass and during heating period were investigated. Proportions between hydraulic power and total power exchange with rock mass are also presented in following research.
Źródło:
AGH Drilling, Oil, Gas; 2017, 34, 1; 123-139
2299-4157
2300-7052
Pojawia się w:
AGH Drilling, Oil, Gas
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimized grid structures for the characteristic diagram based estimation of thermo-elastic tool center point displacements in machine tools
Autorzy:
Putz, M.
Ihlenfeldt, S.
Naumann, C.
Glänzel, J.
Powiązania:
https://bibliotekanauki.pl/articles/100061.pdf
Data publikacji:
2017
Wydawca:
Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:
characteristic diagram
adaptive structured grids
thermoelastic deformation
grid optimization
thermal error estimation
Opis:
It is a well-known problem of milling machines, that waste heat from motors, friction effects on guides and also the milling process itself greatly affect the positioning accuracy and thus the production quality. An economic and energy-efficient method of correcting this thermo-elastic positioning error is to gather sensor data from the machine tool and the process and to use that information to predict and correct the resulting tool center point displacement using high dimensional characteristic diagrams. The size of these characteristic diagrams depends on the number of input variables (sensors) and the fineness of the discretization of the grid. While the number of sensors can usually not be reduced without affecting the quality of the prediction, it is often possible to minimize the size of characteristic diagrams through the use of adaptive grid refinement. This ensures that the finest grid sections correspond with the load cases that have the largest local gradients. Through such adaptive refinement, it is possible to reduce storage capacity and computation time without significant loss of precision. The aim of this article is to examine, test and compare different methods of adaptive grid refinement. For this, simulation data from a machine tool is used.
Źródło:
Journal of Machine Engineering; 2017, 17, 3; 36-50
1895-7595
2391-8071
Pojawia się w:
Journal of Machine Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Characteristic of Oxide Layers Obtained on Titanium in the Process of Thermal Oxidation
Autorzy:
Aniołek, K.
Kupka, M.
Barylski, A.
Mieszczak, Ł.
Powiązania:
https://bibliotekanauki.pl/articles/354531.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
titanium
oxidation
scale
structure
hardness
Opis:
Thermal oxidation in air may be one method to improve the properties of titanium and its alloys through its influence on the structure and properties of the material’s surface layer. This paper presents a description of oxide layers obtained on the surface of Grade 2 titanium as a result of oxidation at temperatures of 600 and 700°C. On the basis of kinetic curves, it was found that the intensity of oxide layer growth increased with oxidation temperature. Studies of the surface morphology of oxide layers showed that the size of the formed oxide particles was greater following oxidation at 600°C. The obtained layers were subjected to X-ray phase analysis and microhardness measurements. Irrespective of oxidation temperature, the scale consisted of TiO2 oxide in the crystallographic form of rutile and of Ti3O oxide. The hardness of oxide layers amounted to around 1265 HV and was more than 4 times higher compared to the material in i ts initial state.
Źródło:
Archives of Metallurgy and Materials; 2016, 61, 2A; 853-856
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hydrogeochemical characteristic of thermal waters in Bańska Niżna
Autorzy:
Korzec, K.
Powiązania:
https://bibliotekanauki.pl/articles/184477.pdf
Data publikacji:
2016
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
recreation
medicine
rehabilitation
Opis:
Thermal waters belong to the greatest treasures of Podhale. They are used not only in heat engineering but also in recreation, medicine and rehabilitation (Kępińska 2004, 2009, Tomaszewska 2009). It is also known that thermal waters are treated and used for drinking or commercial purposes (Bujakowski & Tomaszewska 2007, Tomaszewska 2009, 2011, Tomaszewska & Bodzek 2013). Thermal waters in Bańska Niżna are exploited by PEC Geotermia Podhalańska S.A. Company. Commercial use of these waters began in 1993, when the system based on geothermal doublet, supplied heat to several houses (Ślimak & Wartak 2009). Currently, the exploitation is made by using three wells: Bańska IG-1 well, Bańska PGP-1 well and Bańska PGP-3 well. Hydrogeochemical characteristic of thermal waters in Bańska Niżna was based on researches concerning the state of those waters, which was being carried out every two weeks between December 2013 and August 2015. Field research was based on measurements of non-stable parameters – pH, electrical conductivity γ 25 and the temperature on the flow. The results of field measurements were supplemented with archival data: water temperature at the well head, pressure and well discharge. The samples for laboratory tests were taken by the author of this work in accordance with the standard ISO 5667-11:2004. The chemical composition analysis of thermal waters was carried out by accredited Hydrogeochemical Laboratory of the Department of Hydrogeology and Engineering Geology AGH in Kraków (certificate of Polish Centre of Accreditation No. AB 1050). This analysis included measurements of concentration of 45 indicators. On the basis of the results of the research, the hydrogeochemical type of thermal waters in Bańska Niżna was defined as sulfate-chloride-sodium-calcium type (according to the classification by Shchukarev–Priklonskiy (Prikłoński & Łaptiew 1955)). The medium values of the basic parameters of analyzed wells, estimated on the basis of data from 2013–2015, are as follows: - Bańska IG-1 well: pH 6.63, γ 25 3.48 mS/cm, temperature at the well head 78.5°C, pressure 11.8 ba, well discharge 58.1 m 3 /h, mineralization 2522.8 mg/dm 3 ; - Bańska PGP-1: pH 6.69, γ 25 3,39 mS/cm, temperature at the well head 85.9°C, pressure 14.4 ba, well discharge 317.3 m 3 /h, mineralization 2533.6 mg/dm 3 ; - Bańska PGP-3: pH 6.72, γ 25 3.43 mS/cm, temperature at the well head 85.0°C, pressure 14.0 ba, well discharge 221.3 m 3 /h, mineralization 2514.3 mg/dm 3. The database from the years 2013–2015 was supplemented by archival results of chemical composition analyzes. On that basis, the assessment of the thermal waters chemical composition stability in Bańska Niżna was prepared, according to the scheme presented in work (Kmiecik & Korzec 2015). It is especially important because physical parameters and chemical composition of geothermal waters can be change during the long-term exploitation. According to Polish law, confirm stability of the physico-chemical parameters is necessary because using these waters in medicine (Dz.U. 2011, nr 163, poz. 981 art. 5). Moreover, the hydrogeochemical model of formation of those waters was defined.
Źródło:
Geology, Geophysics and Environment; 2016, 42, 1; 85-86
2299-8004
2353-0790
Pojawia się w:
Geology, Geophysics and Environment
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Implementation and demonstration of characteristic diagram as well as structure model based correction of thermo-elastic tool center point displacements
Autorzy:
Putz, M.
Ihlenfeldt, S.
Kauschinger, B.
Naumann, C.
Thiem, X.
Riedel, M.
Powiązania:
https://bibliotekanauki.pl/articles/99680.pdf
Data publikacji:
2016
Wydawca:
Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:
hexapod
characteristic diagram
thermal error
simulated
measured
correction algorithm
Opis:
In milling machines, waste heat from motors, friction effects on guides and most importantly the milling process itself greatly affect positioning accuracy and thus production quality. Therefore, active cooling and lead time are used to reach thermal stability. A cheaper and more energy-efficient approach is to gather sensor data from the machine tool to predict and correct the resulting tool center point displacement. Two such approaches are the characteristic diagram based and the structure model based correction algorithms which are briefly introduced in this paper. Both principles have never been directly compared on the same demonstration machine, under the equal environmental conditions and with the same measurement setup. The paper accomplishes this comparison ona hexapod kinematics examined in a thermal chamber,where the effectiveness of both approaches is measured and the strengths and weaknesses of both are pointed out.
Źródło:
Journal of Machine Engineering; 2016, 16, 3; 88-101
1895-7595
2391-8071
Pojawia się w:
Journal of Machine Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 24

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