The membrane properties of alumina-coated alumina support layers and alumina-coated diatomite–kaolin composite support layers

ABSTRACT

Porous ceramic membranes are a current research focus because of their outstanding thermal and chemical stability. Recent research has utilised inexpensive natural materials such as diatomite to reduce the expense of these porous ceramic membranes. However, insufficient data exist for microfiltration applications using the diatomite-based membranes. The measured membrane properties of alumina-coated alumina support layers and alumina-coated diatomite–kaolin composite support layers have been compared. These experiments have been used to determine whether the average pore size could be reduced effectively by controlling the thickness of the alumina coating layer, while maintaining acceptable water permeability. The membrane properties of the alumina-coated alumina support layers and the alumina-coated diatomite–kaolin composite support layers were examined using the scanning electron microscopy, mercury porosimetry, and a dead-end microfiltration system.     

Failure Analysis of HAZ Cracking in Low C–CrMoV Steel Weldment

This case study describes the failure analysis of steel nozzle in which cracking was observed after a circumferential welding process. The nozzle assembly was made from low C–CrMoV alloy steel that was subsequently single pass butt welded using gas tungsten arc welding. No cracks were found in visual inspection of the welds; however, X-ray radiography showed small discontinuous cracks on the surface in the area adjacent to weld bead, i.e. heat affected zone. The welding of nozzle parts made of same material was a routine process and this type of cracking did not occur in the past. Therefore, it became essential to determine the root cause of the failure. A detailed investigation including visual examination, non-destructive testing, optical microscopy, microhardness measurements and residual stress measurements were carried out to find out the primary cause of failure and to identify actions required to avoid its reoccurrence in future. Results of the investigation revealed that the principal cause of failure was the presence of coarse untempered martensite in the heat affected zone due to localized heating. The localized heating was caused by high welding heat input or low welding speed and resulted in the high transformation stresses. These transformation stresses combined with the thermal stresses and the constraint conditions to cause intergranular brittle fracture.     

Adhatoda vasica in Conjunction with Binary Combinations of Metal Salts and Biomordants as an Effective Textile Dye to Produce novel Shades on Wool

This study was undertaken to propose an alternative use of Adhatoda vasica leaves extract as a potential source of natural dye for the coloration of woolen yarn/fibers. Premordanting technique was adopted with double metal salt combinations of ferrous sulfate, stannous chloride, and potassium aluminum sulfate and double biomordant combinations of gallnut, pomegranate, and babool, to achieve dyed textile materials of acceptable colorimetric and fastness properties. Sixty-three sober and elegant shades were developed on wool by varying the nature and the concentration of mordants involved in the combinations. The hue of color developed was found to be in yellow-red coordinate of color space diagram. All the dyed samples presented excellent color strength (K/S) values and highest values were found in case of gallnut + pomegranate peel extract (PPE) combination. Biomordants produced altogether different behavior in comparison to metal mordants in the development of ecofriendly shades of different hue and tune. Majority of the dyed samples showed excellent fastness properties with respect to light, washing, and rubbing which confirmed the possibility of using A. vasica leaves extract as an effective yellow natural dye.     

Bi and Tri Metal Salt Combinations plus Colorants Extracted from Timber Industry Waste as Effective Dyeing Materials to Produce Novel Shades on Wool

This study was undertaken to propose alternative use for teak leaves, a timber industry byproduct, as potential dyeing source for wool fibers. The coloring potential of anthraquinone colorants from teak leaves were studied on wool with pre-mordanting method using double and triple mix metal salt combinations (ferrous sulphate, stannous chloride and potassium aluminum sulphate) as mordants. Thirty-six sober and elegant shades were developed on wool by varying the type of metal involved in combination as well as concentration of the dye. The hue of color developed ranged from light orange—brown to dark brown. The color strength (K/S) has been found to be very good in dyed woolen yarn samples and particularly was highest for iron + alum combination. Color fastness with respect to light exposure washing, rubbing for the developed shades ranged between good to very good, which confirmed the possibility of using waste leaves of Tectona grandis as a source of effective brown natural dye.     

Modulation of extraction variables of pectin from Manilkarazapota fruit peel,its bio characterization,and comparative study using dynamic light scattering studies

Influence of variables has a great impact upon yield of pectin. The present study was organized to harmonize these variables and examine the extracted pectin. In view of this, bio-characterizion and structure analysis of pectin through FTIR was performed. Additionally, a polydispersity and particle size study was also conducted using dynamic light scattering (DLS) of the Manilkarazapota fruit peel. The best extraction variables according to the response optimization predicted model were noted as pH of 5 at 61.11°C for 90 min of heating time, which lead to a 3.7% yield. Bio-characterization revealed that pectin extracted at pH 5 has characteristics similar to HM pectin influence of methoxyl content, degree of esterification, and Galacturonic acid content at 5.11%, 73. 63%, and 77.7%, respectively. The FTIR spectrum depicted a similar surface structure to food-grade pectin. DLS studies revealed that extracted pectin at pH 5 has a particle size in the range of 390.21–421.17 nm and polydispersity (?) of 28.2%-29.3%. These findings indicate that sapodilla is a potential source of pectin for food and pharmaceutical preparation.     

Coupled snakelets for curled text-line segmentation from warped document images

Camera-captured, warped document images usually contain curled text-lines because of distortions caused by camera perspective view and page curl. Warped document images can be transformed into planar document images for improving optical character recognition accuracy and human readability using monocular dewarping techniques. Curled text-lines segmentation is a crucial initial step for most of the monocular dewarping techniques. Existing curled text-line segmentation approaches are sensitive to geometric and perspective distortions. In this paper, we introduce a novel curled text-line segmentation algorithm by adapting active contour (snake). Our algorithm performs text-line segmentation by estimating pairs of x-line and baseline. It estimates a local pair of x-line and baseline on each connected component by jointly tracing top and bottom points of neighboring connected components, and finally each group of overlapping pairs is considered as a segmented text-line. Our algorithm has achieved curled text-line segmentation accuracy of above 95% on the DFKI-I (CBDAR 2007 dewarping contest) dataset, which is significantly better than previously reported results on this dataset.     

A research on an intelligent multipurpose fuzzy semantic enhanced 3D virtual reality simulator for complex maritime missions

In this article, the idea of multipurpose fuzzy semantic enhanced 3D virtual reality simulator for the evaluation of maritime robot algorithms, and for the analysis of maritime missions is presented. The simulator uses the digital mockup technology in blending with semantic domain knowledge of the system, to analyze the tasks remotely. The 3D virtual reality (VR) is proposed to help the operators provide the detailed information and guidance during real-time tele-operations, and the incorporation of fuzzy semantic knowledge makes the virtual environment intelligent and automatic. The integration of fuzzy scene independent ontology with the virtual environment (VE) engenders a knowledge driven inter operable virtual environment which eases the user in natural language querying, personalization, interpretations and manipulation. The distinctive semantic VR scene builder utility of the proposed system draws the VR environment automatically while getting the high level specification of the system for the client. The proposed simulator can be effectively used for real-time robots trainings and for the evaluation of AI based algorithms designed for intelligent vessels and AUV’s without knowing the complex underlying VR scene building technologies. Furthermore, it provides the benefits to optimize the pre-process physical environment operations to mimic the real world into a virtual environment. The remote operations and feasibility analysis performed on virtual simulator can efficiently save the cost, time and claims to provide the operators a preprocessor information and guide.     

Effect of Cyclic Aging on Mechanical Properties and Microstructure of Maraging Steel 250

The effects of thermal cyclic aging on mechanical properties and microstructure of maraging steel 250 were studied using hardness tester, tensile testing machine, impact tester, optical, scanning electron, and stereo microscopy. Samples were solution annealed at 1093 K for 1 h followed by air cooling to form bcc martensite. Cyclic aging treatments were carried out at 753 and 773 K for varying time periods. Increase in hardness and strength with corresponding decrease in ductility and impact strength was observed with increasing aging cycles. Reverted austenite was detected by x-ray diffraction technique formed as a result of cyclic aging. The presence of reverted γ was also confirmed by EDX-SEM analysis and attributed to the formation of Mo- and Ni-rich regions which transformed to γ on cooling. Heterogeneity in composition and amount of reverted γ was found to increase with increase in aging cycles and aging time. Fractography reveals the change in fracture mode from ductile dimple-like to brittle cleavage with increase in hardness and strength due to cyclic aging.     

Investigation into Microstructures of Maraging Steel 250 Weldments and Effect of Post-Weld Heat Treatments

This study was undertaken to gain a better understanding of microstructures obtained by multipass gas tungsten arc welding in maraging steel grade 250. Metallography and microhardness measurements were carried out on sheet and welded joints in as-welded and post-weld aged conditions. It was found that there was a significant amount of reverted austenite formed on cell boundaries of weld metal after aging at 758-823 K for 3-5 h, and was stable at room temperature. Aging at higher temperatures led to an increase in the continuous network of patchy austenite along the cell boundaries. The reason for the above, in our opinion, is the concentrational heterogeneity which characterizes the microstructure of maraging steel welds. No reverted austenite was observed in as-welded specimens. Solution annealing at 1093 K for 1 h did not completely eliminate the chemical heterogeneity associated with weld structures. However, homogenizing at 1373 K produced homogenous structure that on subsequent aging produces austenite-free lath martensitic structure.