Infiltrated Layer Research Articles

Comparison of Stefan model with Single-phase model of water infiltration process in unsaturated porous media (theory and experiment)

Summary Stefan models have been used for many problems such as freezing and melting processes. However, there are few research reports on using Stefan model for the problem of unsaturated flow in a granular packed bed, but the Stefan model has never been used before for considering the effects of particle sizes and supplied water flux to water saturation and moving infiltration fronts. The purpose of this work is to present novel mathematical models and numerical schemes for solving one-dimensional infiltration flow problems. A systematic development and comparison of two proposed models (Single-phase model and Stefan model) is performed. The influences of particle sizes and supplied water flux on water infiltration, i.e., the infiltration layer are studied in detail. It is found that the results of the comparison between these two models are in good agreement. Furthermore, the Stefan model shows better agreement with the experimental results than the Single-phase model. This study shows that the Stefan model can be used effectively for many physical phenomena involving flow infiltration coupled with a moving boundary, compared with other conventional models, i.e., the Single-phase model.

Clinical and Pathological Characteristics of Intraocular Cysticercosis

This study aimed to explore the clinical, radiological, and pathological characteristics of intraocular cysticercosis due to Taenia solium metacestode infection. Total 8 patients diagnosed with intraocular cysticercosis at the Red Cross Hospital of Yunnan Province, China were examined retrospectively. Patients with clear dioptic media had undergone fundus chromophotography. All patients underwent B ultrasonography of the ocular region (CT) successive scanning of the orbit and cerebral tissues. Parasites were extracted surgically and then examined pathologically. The fundus chromophotography showed a white and condensing scolex package in the vesicle. The B ultrasonic examination showed a vesicle-like echogenic mass in the vitreous chamber, in which the high-level echo spot was the cysticercus scolex. The pathological examinations showed that the vesicle wall exhibited hyaline degeneration, inflammatory cell infiltration, neuroglial fiber, and glial cell proliferation layers from the inside to the outside. The scolex is round and is composed of the outer tissue (the body wall) and the inner furrow tissue; these tissues migrated together. Primordially differentiated sucking discs were found in one case, but no hooklets were found. The inner scolex tissue was folded like a paper flower. The severity of intraocular disease is closely correlated with the pathophysiological processes of the cysticercus worm. Pathological examination of the intraocular lesions can help to evaluate the course of the disease as well as to provide a scientific basis for effective antiparasitic medication.

The Effects of Temperature and Time on Cu-Ce Infiltration Layer of 304 Stainless Steel by Double Glow Plasma Surface Metallurgy

The Cu-Ce infiltration layer was formed on 304 Stainless Steel surface by double glow plasma surface metallurgy technology. The effects of heat insulation temperature and heat insulation time on surface alloying concentration, surface hardness and infiltration layer depth were analyzed by comparative test. The results showed: In the experimental range, the contents of Cu and Ce, surface hardness, diffusion layer depth increase with the temperature and time increasing; the deposition layer depth increases with time increasing and decreases with temperature increasing in a certain range.

Effect of chitosan/riboflavin modification on resin/dentin interface: Spectroscopic and microscopic investigations

The aim of this study is to investigate the morphological and chemical changes of demineralized dentin collagen-matrix and resin/dentin interface associated with chitosan/riboflavin modification. Dentin disc specimens were prepared from sound molars, acid-etched with 35% phosphoric acid and modified with either 0.1% riboflavin or chitosan/riboflavin (Ch/RF ratios 1:4 or 1:1) and photo-activated by UVA. Morphological and chemical changes associated with surface modification were characterized by SEM and micro-Raman spectroscopy. Dentin surfaces of sound molars were exposed, acid-etched, and modified as described before. Etch-and-rinse dentin adhesive was applied, light-cured, and layered with resin-restorative composite. The resin infiltration and resin/dentin interface were characterized by micro-Raman spectroscopy and SEM. An open-intact collagen network-structure, formation of uniform hybrid-layer and higher resin infiltration were found with 0.1%RF and Ch/RF 1:4 modifications. Raman analysis revealed chemical changes and shifts in Amide bands with the modification of dentin collagen-matrix. The use of riboflavin and chitosan/riboflavin formulations to modify dentin-collagen matrix, with the defined ratios, stabilizes the collagen fibrillar network and enhances resin infiltration and hybrid layer formation. These preliminary results are encouraging for subsequent consideration of chitosan/riboflavin modification in adhesive dentistry.

Mesoporous Metal Oxides by Vapor Infiltration and Atomic Layer Deposition on Ordered Surfactant Polymer Films

Catalysis, chemical separations, and energy conversion devices often depend on well-defined mesoporous materials as supports or active component elements. Herein, we show that ordered assembled organic surfactant films can directly template porous inorganic solids with surface area exceeding 1000 m(2)/g by infusing the polymers with reactive inorganic vapors, followed by anneal. The specific surface area, pore size, chemical composition, and overall shape of the product material are tuned by choice of the polymer and precursor materials as well as the influsion and postinfusion treatment conditions. X-ray diffraction, infrared spectroscopy, and electron microscopy show that vapor infusion changes both the physical and chemical structure of the starting ordered polymer films, consistent with quantified trends in specific surface area and pore size distribution measured by nitrogen adsorption after film annealing. This method yields porous TiO(2) films, for example, that function as an anode layer in a dye-sensitized solar cell.

The Effects of Voltage on Cu-Ce Infiltration Layer of 304 Stainless Steel by Double Glow Plasma Surface Metallurgy

The Cu-Ce infiltration layer was formed on 304 Stainless Steel surface by double glow plasma surface metallurgy technology. The effects of source voltage and cathode voltage on surface alloying concentration, surface hardness and infiltration layer depth were analyzed by comparative test. The results showed: In the experimental range, the contents of Cu and Ce, surface hardness, deposition layer depth increase with the source voltage increasing, which is contrary to the cathode voltage; the diffusion layer depth increases with either voltage increasing in a certain range.

P-0284 Importance of Endorectal Sonography in Rectal Cancer Staging (Poster Presentation)

ABSTRACT Introduction The staging of rectal cancer is a crucial part of the complex therapy of this form of cancer. The purpose of this study was to assess the diagnostic validity of three- dimensional (3D) endoluminal ultrasound at preoperative 3D staging of rectal cancer (uT). Methods The preoperative staging of rectal cancer has been made at our Surgical Department for 20 years. The method of 3D endosonography was introduced in 2000. During the period from 8/2005 to 12/2010, the 3D endorectal sonography was used in 236 examination of rectal tumour. Malignant rectal cancer was diagnosed in 156 patients and that method was indicated in 80 cases for adenomatous or villous rectal polypus. Endosonography shows 5 layers of the rectal wall – three hyperechogenic layers (mucous, submucous, periproctal adipose tissue) and two hypoechogenic layers (muscularis mucosae, muscularis propria). Tumours of uT1 stage show the infiltrated mucous layer and submucosa. Tumours of uT2 stage infiltrate the muscularis propria, uT3 carcinomas infiltrate the whole rectal wall up to the periproctal adipose tissue, and uT4 carcinomas infiltrate the periproctal adipose tissue or adjacent organs. All our patients underwent surgical intervention. Endorectal approach by using an operation rectoscope was applied by patients with uT1 and uT2 stage who had tumour of 3 cm in diameter of G1-2 grading. All surgical samples were examined by one histopathologist. Results The preoperative rectal cancer staging by 3D endorectal sonography correlated with histopathology in 136 patients (87.5%). The up-staging by 3D endorectal sonography was seen in 16 patients (10.3%). The up-staging was assessed in 7 cases of histopathologic pT1 stage evaluated by endorectal sonography as uT2, in 6 patients with histopathologic stage pT2 evaluated as uT3 and in 3 cases of histopathologic pT3 stage evaluated by endorectal sonography as uT4. The down-staging at 3D endorectal sonography was seen in 4 patients (2.3%). It was histopathologic stage pT4 evaluated by endorectal sonography as uT3-T4. Conclusion The data indicate that the preoperative staging of malignant rectal cancer by 3D endorectal sonography results in 100% detection only in the pT1 stage. In pT2 stage the staging accuracy of 3D endorectal sonography was the lowest at 75%, but in stage pT3 it was 85.5% and in pT4 it was 94%. According to our experience, the interpretation of findings obtained by 3D endorectal sonography at limits of T2 – T3 and T3 – T4 is the most difficult. The reason for this is the peripheral reactive fibrous and inflammatory reaction near the tumor tissue often involves the adjacent rectal wall and it echogenecity is the same as the tumor and this results in the overestimation of invasion depth during endorectal sonography of cancer.

Corrosion Resistance of Copper Infiltrated on 0Cr18Ni9 Austenitic Stainless Steel by Plasma Surface Technology

Copper is infiltrated on 0Cr18Ni9 austenitic stainless steel surface by Double Glow Plasma technology, the surface copper content is about 3.5%, content of Cr in metal infiltration layer reaches up to 29.2%. Under the conditions of normal pressure and temperature, corrosion resistance of stainless steel samples which copper infiltrated on surface was researched in 1 mol/L NaOH solution by measurement method of electrochemical. The result shows that, corrosion resistance of copper-infiltrated stainless steel is about 1.67 times higher than untreated sample in 1 mol/L NaOH solution.

Study on Surface Infiltration Casting of Low-Carbon Ductile Iron

In this essay, the surface microstructure of infiltration casting of low-carbon ductile iron was studied in detail. The results show that the micro hardness from the cast infiltration layer to the matrix zone increased at first and then decreased, the maximum micro hardness was about HV1400, maternal surface hardness are greatly enhanced. Low carbon ductile iron can obtain good surface microstructure by using casting infiltration technology. The hardness of alloy layer on low carbon ductile iron matrix is greatly improved.

New pathological insights into cardiac amyloidosis: implications for non-invasive diagnosis

Background: Knowledge of the patterns of myocardial amyloid accumulation could improve the interpretation of electrocardiographic, echocardiographic and magnetic resonance imaging findings of amyloidosis. We assessed the extent and pattern of myocardial amyloid infiltration in explanted or autopsied hearts of patients with cardiomyopathy related to acquired monoclonal immunoglobulin light-chain (AL) or hereditary transthyretin (TTR) related amyloidosis (ATTR). Methods: We analyzed nine explanted/autopsied hearts from patients with AL (n = 4) and ATTR (n = 5) cardiac amyloidosis. For each heart, a biventricular histological macrosection was obtained at mid-ventricular level and analyzed with both inspective and computer-assisted histologic and histomorphometric analysis aimed in particular at quantifying muscle cells, fibrosis and amyloid infiltration. Results: The extent of amyloid infiltration of the left ventricle (LV) ranged from 45 to 76% (median [interquartile range (IQR)] = 57% [51–64]) of the overall surface. Although LV trabecular and subendocardial were the most infiltrated layers (45–94%, median [IQR] = 73% [67–84] and from 44 to 71%, median [IQR] = 57% [49–59], respectively), intra- and inter-patient heterogeneity was high. Three main patterns of amyloid infiltration of the LV were identified: diffuse (five cases), mainly subendocardial (two cases), and mainly segmental (two cases). The extent of amyloid infiltration of the right ventricle ranged from 48 to 93% (median [IQR] = 61% [59–83]); contributions of parietal and trabecular layers ranged from 32 to 99% (median [IQR] = 63% [47–88]) and from 49 to 93% (median [IQR] = 74% [64–79]), respectively. Conclusions: In amyloidotic cardiomyopathy, amyloid deposition is highly heterogeneous. Different patterns of infiltration are identifiable, including diffuse, mainly segmental and mainly subendocardial. Awareness of this variability can help the interpretation of ECGs, echocardiograms and magnetic resonance imaging.

Stacking of Ceramic Inverse Opals with Different Lattice Constants

The feasibility of stacking of thin ceramic inverse opals with incommensurable periodicity constants was investigated. Inverse opals with photonic stopgaps in the infrared range were prepared by the vertical convective self‐assembly from aqueous suspensions of monodisperse polystyrene (PS) particles with the sizes of 476, 608, and 756 nm. The opal templates were infiltrated with TiO2 by a low‐temperature atomic layer deposition process using titanium isopropoxide and water as precursors. The second PS template could be deposited on top of the infiltrated opal layer after exposing the latter to the UV‐light, which rendered its surface hydrophilic. Finally, the sacrificial PS templates were removed by calcination at 500°C. It is shown that smoothness of the surface of the inverse opals is crucial for the photonic performance of the heterostructures. Two well‐defined stopgaps could be observed in the spectra of reflectance of the stacked inverse opals with improved surface morphology.

Wear performance of Ni/ZrO2 infiltrated composite layer

The Ni/ZrO2 was used as raw materials to fabricate the surface infiltrated composite layer with 1–4 mm thickness on cast steel substrate through vacuum infiltrated casting technology. The microstructure indicated that the infiltrated composite layer included surface composite layer and transition layer. Wear property was investigated under room temperature and 450°C. The results indicated that the abrasion volume of substrate was 8 times that of the infiltrated composite layer at room temperature. The friction coefficient of infiltrated composite layer decreased with the increasing load. The wear resistance of infiltrated composite layer with different ZrO2 contents had been improved obviously under high temperature. The friction coefficient of infiltrated composite layer was decreased comparing with that at room temperature. The oxidation, abrasive and fatigue abrasion was the main wear mechanism at room temperature. Oxidation abrasion, fatigue wear and adhesive wear dominated the wearing process under elevated temperature.

Research on Renitrocarburizing of Mechanical Element

Analyzes the reason why renitrocarburized element could not get desired surface quality as the first. Improve the craft. Conduct trial and testing. The surface hardness and compounds layer depth of the Renitrocarburized element can back to the same level as the first time. Furthermore, the infiltration layer microstructure is consistent with that in the first nitro carburizing.

Georadar‐derived estimates of firn density in the percolation zone, western Greenland ice sheet

Greater understanding of variations in firn densification is needed to distinguish between dynamic and melt‐driven elevation changes on the Greenland ice sheet. This is especially true in Greenland's percolation zone, where firn density profiles are poorly documented because few ice cores are extracted in regions with surface melt. We used georadar to investigate firn density variations with depth along a ∼70 km transect through a portion of the accumulation area in western Greenland that partially melts. We estimated electromagnetic wave velocity by inverting reflection traveltimes picked from common midpoint gathers. We followed a procedure designed to find the simplest velocity versus depth model that describes the data within estimated uncertainty. On the basis of the velocities, we estimated 13 depth‐density profiles of the upper 80 m using a petrophysical model based on the complex refractive index method equation. At the highest elevation site, our density profile is consistent with nearby core data acquired in the same year. Our profiles at the six highest elevation sites match an empirically based densification model for dry firn, indicating relatively minor amounts of water infiltration and densification by melt and refreeze in this higher region of the percolation zone. At the four lowest elevation sites our profiles reach ice densities at substantially shallower depths, implying considerable meltwater infiltration and ice layer development in this lower region of the percolation zone. The separation between these two regions is 8 km and spans 60 m of elevation, which suggests that the balance between dry‐firn and melt‐induced densification processes is sensitive to minor changes in melt.

Analysis of the interdiffusion of resin monomers into pre-polymerized fiber-reinforced composites

ObjectivesThe aim of the study was to analyze the dissolving depth of adhesive resin monomers into pre-polymerized fiber-reinforced composites (FRC) with either a semi-interpenetrating polymer network (semi-IPN) or a cross-linked polymer (CLP) matrix. MethodsFive unidirectional FRCs were tested, including one semi-IPN FRC (everStick® C&B, StickTech, (ES)) and four CLP-FRCs (GrandTec®, VOCO, (GT); Dentapreg®, ADM, (DP); TenderFiber®, Micerium, (TF); Splint-It®, Pentron Clinical Technologies, (SI)). The FRCs were light-polymerized following manufacturers’ instructions: the oxygen inhibition layers were removed and the adhesive resin (Optibond-FL®, KerrHawe) was labeled with a fluorescent dye (Rhodamine-B-isothiocyanate), which was then applied to the FRCs (5min) and light-polymerized (40s). Specimens were then prepared for confocal laser scanning microscopy. Three FRC strands per group were sectioned orthogonally to the direction of fibers, thus forming nine slices in each group. Four images were taken from each slice and the depths of adhesive penetration were measured in four sites per image (n=144 measurements per group). SignificanceDissolving depths were 17.28 (3.04)μm (ES), 12.58 (2.94)μm (SI), 7.57 (1.91)μm (TF), 3.27 (0.73)μm (DP) and 2.55 (0.63)μm (GT). Samples were normally distributed. Differences between groups were analyzed by ANOVA (PostHoc Scheffé) showing four subgroups (p=0.05). The infiltration layers detected were either continuous/homogenous (ES, TF, DP GT) or discontinuous/insular (SI). ConclusionThe adhesive resin monomers were able to diffuse significantly deeper into pre-polymerized semi-IPN specimens than into CLP materials. Semi-IPN specimens showed a homogenous and comparatively deeper layer of infiltration. The diffusion capabilities of secondary-IPN formation might increase the opportunity to establish a good bond between pre-polymerized FRC and new resin.

A Surface Melting Infiltration Study on Cast Magnesium Alloy

A new technique has been developed by infiltration during casting process to AZ91D magnesium alloy part. Through a melting process a alloyed surface layer was formed on the surface of the part in casting process, and the surface layer helps improve the corrosion resistance. The macro morphology, thickness, microstructure and properties of the layer were analyzed by digital, scanning electron microscopy, spectroscopy and corrosion measurement system. The results show that a uniform and dense infiltration layer on the surface of AZ91D part was obtained. This technique can fundamentally change the physical and chemical properties of magnesium alloy parts. More importantly, it is low-cost, green and environmental protection.

The Microstructure of Ni-Based Surface Infiltrated Layer on Cast Steel Substrate

The Ni-based alloying powder was successfully used as the raw materials for fabricating surface infiltrated layers on cast steel ZG45 substrate through a vacuum infiltration casting technique (VICT). The microstructures of surface Ni-based infiltrated layer, the micro-hardness distribution are investigated. The infiltrated layer includes three areas that are surface part-melting area, melting completely fusion area and diffusion solid solution area. The main composition of surface infiltrated layer was intermetallic compound Cr2B，NiB and solid solution. The main phase of transition layer was solid solution. The micro-hardness of Ni-based infiltrated layer presented gradient change from surface infiltrated layer to substrate. The average micro-hardness was about 550HV.

Microstructure of Ni / WC surface composite layer on gray iron substrate

The surface infiltrated composite (Ni/WC) layers on gray iron substrate were fabricated through a vacuum infiltration casting technique (VICT) using Ni-based composite powder with different WC particles content as raw materials. The microstructures of surface infiltrated composite layer, the interface structures between surface composite layer and the substrate, the changes of macro-hardness with the increasing of WC content and the micro-hardness distribution are investigated. The infiltrated composite layer includes a surface composite layer and a transition layer, and the thickness of the transition layer decreases with the increasing content of WC. The thickness of transition layer with 20%WC content in the surface infiltrated composite layer was 170 μm which was the thickest for all transition layers with different WC content. The surface composite layer was mainly composed of WC, W2C, FeB and NiB, along with Ni-Cr-Fe, Ni (Cr) solid solution, Ni (Si) solid solution and Ni (Fe) solid solution. The transition layer was composed of Ni (Cr) solid solution, Ni (Fe) solid solution, Ni (Si) solid solution, Fe (Ni) solid solution and eutectic. The surface macro-hardness and micro-hardness of the infiltrated layer had been evaluated. The macro-hardness of the surface composite layer decreases with the WC content increasing, and the average macro-hardness is HRC60. The distribution of micro-hardness presents gradient change. The average micro-hardness of the infiltrated layer is about HV1000.

The Microstructure of Ni/ZrO<sub>2</sub> Infiltrated Composite Layer

The Ni/ZrO2 composite powder was used as raw materials to fabricate the surface infiltrated composite layer on cast steel substrate through vacuum infiltrated casting technology. The microstructure indicated that the infiltrated composite layer included surface composite layer, Ni-based alloying layer and diffusion transition layer. The thickness of diffusion transition layer deceased with the increasing thickness of preform. The surface infiltrated composite layer was composed of ZrO2 ceramic particles, Cr2B and NiB intermetalic compounds as well as Ni-based solid solution. The Ni-based solid solution and Fe-based solid solution was the main composition for diffusion transition layer. The change of micro-hardness of surface infiltrated composite layer presents gradient from surface of infiltrated layer to substrate.

Mechanism study on formation and chemical changes of calcium aluminate inclusions containing SiO2 in ladle treatment of tool steel

The formation and chemical changes of non-metallic inclusions in the ladle treatment were studied with laboratory experiments and theoretical analysis. Refractory samples covered by the ladle glaze were taken from used ladle and examined. The detachment of ladle glaze and the chemical transformations of oxide solution in the MgO matrix were investigated. After 120 min of reaction with liquid steel, the infiltrated layer of ladle glaze still remained on the surface of refractory samples. This observation showed evidently that the ladle glaze could be the source of inclusions continually during the ladle treatment. The results also explained why the infiltrated liquid oxide could supply inclusion to the steel after two heats. Samples of liquid oxide solution to simulate the liquid oxide inclusions carried over from electric arc furnace (EAF) were equilibrated with liquid steel under controlled atmosphere. The experimental results along with thermodynamic calculation suggested that the SiO2 content of inclusions carried over from the EAF could be considerably reduced by dissolved aluminium in the steel. This would explain the vanishing of the liquid inclusions containing 30 mass-%SiO2 after deoxidation in ladle treatment.