Amine-based solvent for CO2 absorption and its impact on carbon steel corrosion: A perspective review

Carbon dioxide (CO₂) is one of the commonly emitted gaseous by-products in industrial processes. While CO₂ gas is the main cause to greenhouse effect, various CO₂ capture technologies have been proposed and implemented to sequester the CO₂ before the waste gases being released into the atmosphere. One of the mature technologies for CO₂ absorption is by using amine-based solvents. In this regard, different single amine solvents or blended amine solvents have been proven for their capability to remove CO₂. However, the dissolution and reaction of CO₂ gas with the amine solvents turn the solution corrosive. Such phenomenon is undesired as it posts corrosion problem to the absorption column, which normally built of carbon steel material. Henceforth, understanding the behaviour of different amine-based solvents in absorbing CO₂ and its subsequent impact on carbon steel corrosion is very significant. In this review article, we will outline some of the more commonly used solvents and their respective advantages and disadvantages, motivating further investigation into the corrosion tendency. Meanwhile, existing gaps in this research area are discussed for future investigation.     

Contrast enhancement dynamic histogram equalization for medical image processing application

Image processing requires an excellent image contrast‐enhancement technique to extract useful information invisible to the human or machine vision. Because of the histogram flattening, the widely used conventional histogram equalization image‐enhancing technique suffers from severe brightness changes, rendering it undesirable. Hence, we introduce a contrast‐enhancement dynamic histogram‐equalization algorithm method that generates better output image by preserving the input mean brightness without introducing the unfavorable side effects of checkerboard effect, artefacts, and washed‐out appearance. The first procedure of this technique is; normalizing input histogram and followed by smoothing process. Then, the break point detection process is done to divide the histogram into subhistograms before we can remap the gray level allocation. Lastly, the transformation function of each subhistogram is constructed independently. © 2011 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 21, 280‐289, 2011;     

Two-stage hybrid optimization of fiber Bragg gratings for design of linear phase filters

We present a new hybrid optimization method for the synthesis of fiber Bragg gratings (FBGs) with complex characteristics. The hybrid optimization method is a two-tier search that employs a global optimization algorithm [i.e., the tabu search (TS) algorithm] and a local optimization method (i.e., the quasi-Netwon method). First the TS global optimization algorithm is used to find a "promising" FBG structure that has a spectral response as close as possible to the targeted spectral response. Then the quasi-Newton local optimization method is applied to further optimize the FBG structure obtained from the TS algorithm to arrive at a targeted spectral response. A dynamic mechanism for weighting of different requirements of the spectral response is employed to enhance the optimization efficiency. To demonstrate the effectiveness of the method, the synthesis of three linear-phase optical filters based on FBGs with different grating lengths is described.     

Chronic effects of dietary selenium on juvenile Sacramento splittail (Pogonichthys macrolepidotus)

The chronic effects of dietary selenium (Se) exposure in juvenile Sacramento splittail (Pogonichthys macrolepidotus) were investigated in the laboratory. A total of 960 (40 fish per tank, 3 tanks per diet) 7-month-old juvenile splittail were fed one of eight Purified-Casein diets supplemented with selenized yeast for 9 months in a flow-through system. These diets contained the following: 0.4 (control), 0.7, 1.4, 2.7, 6.6, 12.6, 26.0, and 57.6 mg of Se kg(-1) dry weight. Survival, Se tissue concentration, growth, gross morphology, and liver histopathology were assessed at 5- and 9-month of exposure. Mortalities occurred only in the two highest Se treatments and were accounted for 8.3 and 18.3% at 5-month and 10.0 and 34.3% at 9-month, respectively. Liver and muscle Se concentration were significantly correlated with dietary Se concentration. Fish exposed to 0.4-12.6 mg of Se kg(-1) diets had reached equilibrium in liver Se concentration by 5 month. Splittail fed diets at concentrations > or =26.0 mg of Se kg(-1) had not reached equilibrium in liver, and muscle Se concentrations and grew significantly slower (p < 0.05) at 5- and 9-month exposure. Se-induced deformities were observed in fish fed > or =2.7 mg of Se kg(-1) diets at 5-month and in fish fed > or =0.7 mg of Se kg(-1) diets at 9-month. Fish fed 26.0 and 57.6 mg of Se kg(-1) diets had higher liver lesion scores at 5-month while fish fed 6.6 and 57.6 mg of Se kg(-1) diet had higher liver lesion scores at 9-month. Results indicate that survivals, growth, changes of tissue Se concentrations, and histopathology of juvenile splittail were dose-dependent, but their response thresholds to dietary Se concentrations differed and depended on treatment concentrations and duration of exposure. Chronic exposure to 6.6 mg of Se kg(-1) diet induced deleterious health effects that can potentially impact survival of juvenile splittail.     

Phase and amplitude dispersion for Earth-satellite propagation in the 20- to 30-GHz frequency range

Amplitude and phase dispersion have been measured for over a year on a 19- and 28-GHz earth-space propagation path. In the experiment amplitude and phase differences were compared for a 28-GHz carrier withpm264-MHz sidebands and a 19-GHz carrier, all transmitted from a COMSTAR satellite. No dispersion (frequency selective fading) was found of the type caused by multipath propagation with a large spread in time delay or by resonances in the propagation medium. The only frequency dependences evident were due to the bulk properties of water in rain. The conclusion from this investigation is that amplitude and phase dispersion should not pose a problem for wideband (on the order of 1 GHz) satellite communication systems operating at frequencies greater than 10 GHz with elevation angles from the earth terminals of greater than15deg.     

Empirical Investigation into Factors Affecting Exporting Construction Services in SMEs in Singapore

The Singapore government is encouraging construction enterprises to venture abroad for exporting their services and become global players since the local construction pie is shrinking and the global market is growing. The Building and Construction Authority of Singapore has revamped the contractors registration system with the hope of bringing about merger and acquisition of companies for improving the local contractors’ standing in the global construction scene. To diversify into new markets in a new environment, which is very different from local environment, requires diversification vis-à-vis exporting strategy. This study examines the attitudes and views of contractors, operating in Singapore (excluding foreign contractors), on how the strategic move should be focused for diversification vis-à-vis exporting services. The aim of this study is to establish the survival skills necessary for Singapore’s construction small and medium sized enterprises (SMEs) to venture abroad. A postal questionnaire survey was conducted and the results show that local construction SMEs who have diversified have reaped the benefits derived from diversification into new markets abroad. The main conclusions are that construction SMEs have to export their services in order to survive and they can enhance their export capabilities by forming a consortium with the help of local government.     

Textured mesh surface reconstruction of large buildings with multi-view stereo

There are three main approaches for reconstructing 3D models of buildings. Laser scanning is accurate but expensive and limited by the laser’s range. Structure-from-motion (SfM) and multi-view stereo (MVS) recover 3D point clouds from multiple views of a building. MVS methods, especially patch-based MVS, can achieve higher density than do SfM methods. Sophisticated algorithms need to be applied to the point clouds to construct mesh surfaces. The recovered point clouds can be sparse in areas that lack features for accurate reconstruction, making recovery of complete surfaces difficult. Moreover, segmentation of the building’s surfaces from surrounding surfaces almost always requires some form of manual inputs, diminishing the ease of practical application of automatic 3D reconstruction algorithms. This paper presents an alternative approach for reconstructing textured mesh surfaces from point cloud recovered by patch-based MVS method. To a good first approximation, a building’s surfaces can be modeled by planes or curve surfaces which are fitted to the point cloud. 3D points are resampled on the fitted surfaces in an orderly pattern, whose colors are obtained from the input images. This approach is simple, inexpensive, and effective for reconstructing textured mesh surfaces of large buildings. Test results show that the reconstructed 3D models are sufficiently accurate and realistic for 3D visualization in various applications.     

Performance measurement of product returns with recovery for sustainable manufacturing

Today's lifecycle of new and emerging products, increase in labour costs in developed countries and user's expectations or behaviours including frequently upgrading items with latest features, influence the growth rate of product disposal to landfill. To reduce the negative impact on the environment, global manufacturers need to take responsibility for designing sustainable products and implementing cleaner production systems for 3R operations (3R–Reuse/Remanufacture/Recycle). Nevertheless, there is still a lack of comprehensive measures for assessing product returns with recovery settings. In this paper, a framework for performance evaluation using design for six sigma methodology is developed to estimate utilisation value of a manufactured product with recovery settings, which accounts for total recovery cost, manufacturing lead-time, minimisation for landfill waste and quality characteristic. Finally, a numerical example based on these performance attributes to assess product utilisation value is presented.     

$nhbox{-ZnO}/nhbox{-GaAs}$ Heterostructured White Light-Emitting Diode: Nanoscale Interface Analysis and Electroluminescence Studies

n-ZnO/n-GaAs heterostructured light-emitting diodes have been fabricated by a low-cost ultrasonic spray pyrolysis technique. Nanoscale interface analysis was carried out with scanning transmission electron microscopy. An ~ 8.6-nm-thick amorphous GaAsZnInO was found in the n -ZnO/n-GaAs interface. A strong and broad white electroluminescence band centered at ~ 525 nm and a weak near-infrared emission peaked at ~ 815 nm were observed when n-GaAs was positively biased. The 815-nm emission is believed to be related to the interface layer, and the 525-nm emission is assigned to the recombination of electrons from conduction band to deep-level holes in the ZnO layer.     

Screening of Chinese medicinal herbs for bioactivity against Sitophilus zeamais Motschulsky and Tribolium castaneum (Herbst)

Extracts of 40 species of Chinese medicinal herb from 32 different botanical families were screened for contact, fumigant and feeding-deterrent activities against the two stored-grain insects Sitophilus zeamais and Tribolium castaneum. Thirty Chinese medicinal herbs exhibited insecticidal or feeding-deterrent activities against the two species of insects. Extracts of Artemisia argyi, Dictamnus dasycarpus, Evodia rutaecarpa, Litsea cubeba, Narcissus tazetta var. chinensis, Polygonum aviculare, Rhododendron molle, Sophora flavescens, Stemona sessilifolia, Tripterygium wilfordii, and Torreya grandis were most active.