scholarly journals In situ thermal characterization of existing buildings aiming at NZEB standard: A methodological approach

2020 ◽  
Vol 2 ◽  
pp. 100008
Author(s):  
Luca Evangelisti ◽  
Claudia Guattari ◽  
Francesco Asdrubali ◽  
Roberto de Lieto Vollaro
Keyword(s):  
Methodological Approach ◽  
Thermal Characterization ◽  
Existing Buildings

scholarly journals Processing and Characterization of Silicon Nitride Nanofiber Paper

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Kei-Peng Jen ◽  
Ronald Warzoha ◽  
Ji Guo ◽  
Michael Tang ◽  
Sridhar Santhanam
Keyword(s):  
Silicon Nitride ◽  
Thermal Insulation ◽  
Reduction Process ◽  
Thermal Characterization ◽  
Nitride Phase ◽  
Mechanical Stiffness ◽  
Precursor Material ◽  
Processing Step

Papers of silicon nitride nanofibers were synthesized by a carbothermal reduction process. These nanofiber papers were synthesized in situ and did not require a secondary processing step. The process utilized silica nanopowders and silica gel as the precursor material. Processing geometry played a crucial role in regulating the growth of the nanofiber papers. Characterization of the nanofiber papers indicated that the nanofibers were of the alpha silicon nitride phase. Both mechanical stiffness and strength of the nanofiber papers were measured. Thermal conductivity and specific heat of the papers were also measured and were found to be lower than many common thermal insulation materials at much smaller thicknesses and were comparable to those values that are typically reported for carbon-nanotube-based buckypaper. Results of the mechanical and thermal characterization indicate that these silicon nitride nanofiber papers can be utilized for specialized thermal insulation applications.

scholarly journals In Situ Atom Probe Deintercalation of Lithium-Manganese-Oxide

2017 ◽  
Vol 23 (2) ◽  
pp. 314-320 ◽  
Author(s):  
Björn Pfeiffer ◽  
Johannes Maier ◽  
Jonas Arlt ◽  
Carsten Nowak
Keyword(s):  
Manganese Oxide ◽  
Chemical Potential ◽  
Methodological Approach ◽  
Ionic Mobility ◽  
Atom Probe ◽  
Lithium Manganese Oxide ◽  
Ionic Conductors ◽  
Lithium Manganese

AbstractAtom probe tomography is routinely used for the characterization of materials microstructures, usually assuming that the microstructure is unaltered by the analysis. When analyzing ionic conductors, however, gradients in the chemical potential and the electric field penetrating dielectric atom probe specimens can cause significant ionic mobility. Although ionic mobility is undesirable when aiming for materials characterization, it offers a strategy to manipulate materials directly in situ in the atom probe. Here, we present experimental results on the analysis of the ionic conductor lithium-manganese-oxide with different atom probe techniques. We demonstrate that, at a temperature of 30 K, characterization of the materials microstructure is possible without measurable Li mobility. Also, we show that at 298 K the material can be deintercalated, in situ in the atom probe, without changing the manganese-oxide host structure. Combining in situ atom probe deintercalation and subsequent conventional characterization, we demonstrate a new methodological approach to study ionic conductors even in early stages of deintercalation.

Thermal characterization of coal using piezoelectric photoacoustic microscopy

1986 ◽  
Vol 64 (9) ◽  
pp. 1184-1189 ◽  
Author(s):  
A. Biswas ◽  
T. Ahmed ◽  
K. W. Johnson ◽  
K. L. Telschow ◽  
J. C. Crelling ◽  
...  
Keyword(s):  
Elastic Properties ◽  
Coefficient Of Thermal Expansion ◽  
Thermal Characterization ◽  
Photoacoustic Signal ◽  
Photoacoustic Microscopy ◽  
Piezoelectric Detection ◽  
Theoretical Predictions ◽  
Coal Macerals

The organic constituents that make up the heterogeneous coal mass are called macerals. Vitrinite and pseudovitrinite are two of the most abundantly occurring macerals in North American coals. Photoacoustic microscopy using piezoelectric detection offers a useful technique for probing the thermal-elastic properties of these coal macerals. The experimental and theoretical conditions under which photoacoustic microscopy can be used to characterize the in situ thermal-elastic properties of macerals, as a function of the percentage of carbon or "rank" of coal, are investigated in this paper. Existing piezoelectric photoacoustic theory has been applied to our sample–transducer configuration to arrive at an expression for the voltage measured from the piezoelectric transducer. The theory indicates that the photoacoustic signal is related to the following sample properties: coefficient of thermal expansion a, bulk modulus B, density ρ, and specific heat c. These properties are coupled together into a dimensionless parameter given by aB/ρc, to which the measured voltage is proportional. Some experimental results used to test the validity of the theoretical predictions are presented. Photoacoustic data gathered on 10 Appalachian Basin coals are plotted as a function of the coal rank. These results are shown to compare favourably with a calculated curve, constructed using independently measured values of a, B, ρ, and c.

scholarly journals Mechanical and Typological Characterization of Traditional Stone Masonry Walls in Old Urban Centres: A Case Study in Viseu, Portugal

Buildings ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 18 ◽  
Author(s):  
José Carlos Domingues ◽  
Tiago Miguel Ferreira ◽  
Romeu Vicente ◽  
João Negrão
Keyword(s):  
Safety Evaluation ◽  
Stone Masonry ◽  
Masonry Walls ◽  
Masonry Buildings ◽  
Existing Buildings ◽  
Urban Center ◽  
In Situ Characterization

Essential for any intervention in existing buildings, a thorough knowledge of both structural and material characteristics is even more important in the case of traditional stone masonry buildings, due both to the variability of this technology’s properties and the degradation buildings might have sustained. In Portugal, a number of in situ and laboratory experimental campaigns has allowed us in recent years to expand the knowledge on the mechanical properties of stone masonry walls. Nevertheless, the existence of different wall typologies built with the same material necessitates that this characterization takes into account the various regional constructive cultures. This paper presents the results obtained through an in-situ characterization campaign carried out in the old urban center of Viseu, for which there is no information available in the literature. Granite stone masonry walls of two different buildings were analyzed and characterized considering their geometrical and material features, contributing to the identification of stone masonry typologies present in the city’s old urban center. Flat-jack testing yielded resistance and deformability parameters to be used both in safety evaluation and intervention design. The properties obtained can be said to be consistent with those deriving from other experimental campaigns, conducted in granite walls of different typologies, throughout the country. Simultaneously, relevant conclusions about the use of flat-jacks to characterize this type of stone masonry were drawn.

Determination of the crystal structure of nifedipine form C by synchrotron powder diffraction

2011 ◽  
Vol 67 (4) ◽  
pp. 357-364 ◽  
Author(s):  
Mauro Bortolotti ◽  
Ivan Lonardelli ◽  
Giancarlo Pepponi
Keyword(s):  
Crystal Structure ◽  
Powder Diffraction ◽  
Molecular Conformation ◽  
Thermal Characterization ◽  
Powder Diffraction Data ◽  
Synchrotron Powder Diffraction ◽  
Metastable Form

The crystal structure of the metastable form C polymorph of nifedipine [C17H18N2O6, 3,5-dimethyl 2,6-dimethyl-4-(2-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate] was determined by means of direct-space techniques applied to high-resolution synchrotron powder diffraction data. The polymorph crystallizes in the space group P\bar 1 and exhibits a molecular packing significantly different from that of the stable modification, with molecules aligned in an orthogonal configuration inside the unit cell. The molecular conformation, on the other hand, remains substantially unmodified between the two polymorphs. Additionally, in situ thermal characterization of nifedipine crystallization behaviour was performed, confirming the nucleation of another metastable polymorph (form B) prior to the complete crystallization of the stable modification. A complete structural characterization of form B was not possible owing to its very limited stability interval.

Electrical Characterization and Failure Analysis Using Operando TEM

2017 ◽  
Author(s):  
Yevheniy Pivak ◽  
H.H. Perez-Garza ◽  
Alexander Zintler ◽  
Leopoldo Molina-Luna
Keyword(s):  
Failure Analysis ◽  
Microelectromechanical Systems ◽  
Real Life ◽  
Electrical Characterization ◽  
Thermal Characterization ◽  
Semiconductor Materials ◽  
Transmission Electron ◽  
Ideal Method

Abstract We present here the development of a system that allows for in-situ studies inside the Transmission Electron Microscope (TEM). Functionalized Microelectromechanical Systems (MEMS) used as sample carriers, referred to as Nano-Chips, contain up to eight electrodes used for simultaneous biasing and heating purposes, enabling electro-thermal characterization of various sample types inside the TEM under real life dynamic conditions. This operando approach is an ideal method to study failure analysis of semiconductor materials, performance of resistive switching devices, batteries, fuel cells, piezoceramics and many more.

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