28 research outputs found
Comparison Study of Energy Intensity in the Textile Industry: A Case Study in Five Textile Sub-sectors
No full textThis paper contributes to the understanding of energy use in the textile industry by comparing the energy intensity of textile plants in five major sub-sectors, i.e. spinning, weaving, wet-processing, worsted fabric manufacturing, and carpet manufacturing in Iran. Results of the study showed that spinning plant electricity intensity varies between 3.6 MWh/tonne yarn and 6.6 MWh/tonne yarn, while fuel intensity ranges between 6.7 MBtu/tonne yarn and 11.7 MBtu/tonne yarn. In weaving plants, electricity intensity ranges from 1.2 MWh/tonne fabric to 2.2 MWh/tonne fabric, while fuel intensity was 10.1 MBtu/tonne fabric and 16.4 MBtu/tonne fabric for the two plants studied. In three wet-processing plants, the electricity intensity was found to be between 1.5 MWh/tonne finished fabric and 2.5 MWh/tonne finished fabric, while the fuel intensity was between 38.2 MBtu/tonne finished fabric and 106.3 MBtu/tonne finished fabric. In addition, some methodological issues to improve such energy intensity comparison analysis and benchmarking in the textile industry is discussed
THREE-DIMENSIONAL RECONSTRUCTION OF HETEROGENEOUS MICROSTRUCTURES BASED ON ONE CUT-SECTION USING TWO-POINT CORRELATION FUNCTIONS AND PHASE RECOVERY
No full textThree-dimensional reconstruction of microstructure and evaluation of the various properties (such as mechanical, thermal, etc.) using limited two-dimensional cut-sections are intriguing subjects in microstructure optimal design. There are many practical cases, including material science, biology and medicine, and petroleum engineering for which only 2D images are available for analysis instead of 3D media. Furthermore, direct reconstruction of heterogeneous microstructures using stitching digitized serial section images is not well-suited to routine engineering applications, because providing the acquired images by FIB-SEM, X-ray computed tomography (micro CT), scanning laser confocal microscopy, and other imaging methods are expensive due to their complicated technology, lack of skilled operators and many other technical issues. Thus, three-dimensional reconstruction of such a heterogeneous microstructure is highly useful in performing homogenization, characterization, and finding correlations between microstructural attributions and effective properties of a material. In this paper, a new and powerful method is presented that reconstructs the microstructure using only one cut-section. The method is based upon correlation functions and phase recovery algorithm. The effective properties of a random heterogeneous material are strongly correlated with a particular formalism called n-point statistics. At first, using the available cut-section, two-dimensional two-point correlation functions are determined.
Then, three-dimensional, two-point correlation functions are approximated using 2D ones. Indeed, using the phase recovery algorithm, based on the approximated correlation functions, the three-dimensional microstructure is reconstructed. Besides the isotropic microstructures, this procedure can be used for reconstruction of transversely isotropic microstructures using only one cut-section. Thermal conductivity for the original and reconstructed microstructures is calculated and compared with each other; it is shown that the proposed method reconstructs the original microstructure with a small error rate. An effective reconstruction procedure enables one to generate close to target structures at will, and a subsequent analysis can be performed on the reconstructed microstructure to obtain approximate macroscopic properties (e.g., mechanical, transport, and electromagnetic properties) of the heterogeneous media
The Analysis of Torsional Shear Strength Test of Sealants for Solid Oxide Fuel Cells
No full textA torsion test recently implemented for solid oxide fuel cell sealant materials is analyzed as a method for measuring the shear strength of sealant for solid oxide fuel cells. The finite element method is used to simulate the stress distribution in the hourglass-shaped steel specimens with intermediate sealant layer with different specimen's dimensions and configurations. Also, it is analyzed how stress concentration changes if the sealant does not completely fill the gap or is squeezed out of gap. The reduction of seal thickness to outer radius ratio results in an increase in stress concentration at the outer edge of sealant. The developed specimens with a hollow halve steel plate as well as the ones with two hollow halve steel plates appear to be suitable choices for torsional shear strength test, reducing the torque for fracture and stress concentrations. Effects of lack of filling and squeezing out of gap onto the stress distribution are negligible compared to the effect of pre-existing discontinuities
Influence of bone microstructure distribution on developed mechanical energy for bone remodeling using a statistical reconstruction method
No full textInternational audienceThe development of a predictive model for bone remodeling is becoming increasingly important for medical applications such as bone surgery or bone substitutes like prostheses. However, as bone remodeling is a complex multiphysics phenomenon and difficult to quantify experimentally, predictive numerical models remain, at best, phenomenologically driven. Patient dependency is often ignored as its influence is usually considered secondary, although it is known to play an important role over long periods of time. Another difficulty to study this patient dependency is the availability of experimental samples to carry out extensive analyses. Using our recently developed statistical reconstruction framework, a set of ''bone like'' microstructures with variety of distributions has been created to study pseudo ''patient variabilities. '' The method provides similar effective stiffness tensor, equivalent stresses, and strain energy distributions for the original and the statistically reconstructed samples. The main outcome of this study is the correlation of similar effective mechanical properties between samples when bone remodeling will depend on the local strain energy distribution as a function of each bone microstructure. It is expected that two different micro-structures with equivalent bone volume fraction will lead to identical bone remodeling in a short period of time, whereas this needs to be proven for long term evolution. This work could be used to develop precise predictive numerical models while developing parametric studies on an infinite number of virtual samples and correlating patient dependency with more precise mechanobiological numerical models
Application of full set of two point correlation functions from a pair of 2D cut sections for 3D porous media reconstruction
No full textThree dimensional reconstruction of porous media using limited statistical information has attracted a great interestin Earth sciences and petroleum engineering. In this study, a fast and reliable method for 3D reconstruction is proposed based on approximation of correlation functionsand phase recovery algorithm using one and two perpendicular cut sections. In the proposed method, initially, full set of two point correlation functions (TPCFs) are extracted from the cut sections. Afterwards, the TPCF vectors are decomposed and then averaged to improve the accuracy of the 3D-TPCFs approximation and improve the capabilities of the reconstruction procedure. To demonstrate the ability of the proposed method to deal with both connectivity and anisotropic issues existed in 3D reconstruction literature, Berea sandstone and a synthetic representative volume element (RVE) are used. Eventually, the reconstruction results of Berea sandstone and the synthetic RVEs are examined based on tortuosityvalues, autocorrelation function and also porositydistribution in comparison with their corresponding original RVEs. Evaluation of tortuosity values in the original and reconstructed RVEs for both Berea sandstone and the synthetic RVE reveals that for every axis of interest, there is a satisfactory agreement between the original and reconstructed RVEs realized using those two cut sections that contain the direction of interest as their common axis. This point indicates that the proposed approach which used two perpendicular cut sections provides more reliable and robust 3D reconstruction RVEs
Room- and High-Temperature Torsional Shear Strength of Solid Oxide Fuel/Electrolysis Cell Sealing Material
No full textThe structural integrity of the sealant material is critical for the reliability of solid oxide fuel/electrolysis stacks. In the current study, a torsion test is implemented to evaluate and compare its shear strength with a partially crystallized glass sealant at room- and operation relevant high-temperatures. Hourglass-shaped specimens with different configurations of hollow- and full-halves are utilized for testing. The fracture surfaces are visualized via optical microscopy and complementary scanning electron microscopy. In addition, cyclic loading is used to investigate potential subcritical crack growth effects in the sealants. Both, the specimens with a hollow-half as well as the ones with two full-halve steel plates yield almost the same nominal shear strengths. The shear fracture stresses decrease with rising temperature, while the fracture mode changes from brittle at room temperature and 600 °C to ductile at 800 °C. The cyclic loading condition indicates subcritical crack growth in the sealant at 600 °C and creep associated damage at 800 °C
Effect of YSZ sol-gel coating on interaction of Crofer22 APU with sealing glass for solid oxide fuel/electrolysis cell
No full textRoom- and High-Temperature Flexural Strength of a Stable Solid Oxide Fuel/Electrolysis Cell Sealing Material
No full textThe structural integrity of the sealing material is critical for the reliability of solid oxide fuel/electrolysis stacks. The current work concentrates on microstructural and mechanical aspects of a sealant material for this application. In particular, the crystallization behavior as a determining factor for the sealants’ mechanical behavior is investigated via high-temperature XRD for 24 h. Furthermore, regarding mechanical properties, three- and four-point bending tests are carried out on sealant bars and head-to-head joined specimens at room- and high-temperatures, yielding in particular relevant fracture stress data. In addition, the elastic modulus is measured by the impulse excitation test from RT to 900 ºC. Tests are done for both as-sintered (as-joined) and annealed samples. The main crystallization appears to happen during the initial joining time. The sealant shows a relatively stable flexural strength in terms of temperature dependency as well as effects of the aging process. In fact, the joined specimens reveal a more than 50% lower flexural strength than glass bars at all temperatures. A complementary finite element simulation indicates the presence of a non-negligible thermal residual stress in joined specimens
Micro-scale evolution of mechanical properties of glass-ceramic sealant for solid oxide fuel/electrolysis cells
No full textThe structural integrity of the sealant is critical for the reliability of solid oxide cells (SOCs) stacks. In this study, elastic modulus (E), hardness (H) and fracture toughness (KIC) of a rapid crystallizing glass of BaO–CaO–SiO2 system termed “sealant G” are reported as determined using an indentation test method at room temperature. A wide range of indentation loads (1 mN–10 N) was used to investigate the load-dependency of these mechanical properties. Values of 95 ± 12 GPa, 5.8 ± 0.2 GPa and 1.15 ± 0.07 MPa m0.5 were derived for E, H and KIC using the most suitable indentation loads. An application relevant annealing treatment of 500 h at 800 °C does not lead to a significant change of the mechanical properties. Potential self-healing behavior of the sealant has also been studied by electron microscopy, based on heat treatment of samples with indentation-induced cracks for 70 h at 850 °C. Although the sealant G is considered to be fully crystallized, evidence indicates that its cracks can be healed even in the absence of a dead load
