Formulation and performance evaluation of a novel coconut oil–based metalworking fluid

Metalworking fluid (MWF) supplies a film of lubricant to abate friction, acts as a cooling media to rebate induced heat, and prevents metal pick-ups by flushing away the chips. Hence a liquid used as a cutting fluid reduces wear on the tool, reduces the energy consumption, and produces a better surface quality on the work piece. This paper describes the formulation of a novel water-soluble MWF and its performance evaluation during straight turning and end milling experiments carried out with AISI 304 stainless steel, mild steel, and cast iron as work piece materials. The MWF was prepared by mixing water with white coconut oil as the base oil and food-grade additives as surfactants. Viscosity, pH value, and biodegradability were measured and compared with a commercially available non-vegetable oil–based MWF. The surface roughness and tool surface temperature were measured throughout the machining experiments, and better performances were observed with the coconut oil–based MWF. Tool tip geometry and flank wear for straight turning machining operation were identified by observing scanning electron microscope (SEM) images.     

Quasi-solid-state dye-sensitized solar cells utilizing TiO2/graphite composite counter electrode and TiO2/N719 sensitizer photoelectrode for low-cost power generation

Journal of Materials Science: Materials in Electronics - Dye-sensitized solar cells (DSCs) have evolved through the highest devotion of the research community as a low-cost alternative for...     

Satellite remote-sensing monitoring of a railway construction project

Current satellite remote-sensing technologies enable the timely and detailed monitoring of human activities on the Earth’s surface. Sub-metre spatial resolution satellite images can picture the ongoing works of railway and highway construction. The synoptic view of satellite images is useful to assist the monitoring and management of such construction projects. In this article, we present an integrated remote-sensing change detection framework applied to monitoring the Light Rail Transport construction in Kuala Lumpur, Malaysia, using sub-metre optical remote-sensing images, Pleiades. Focusing on the known local area surrounding a construction site, the recognition process starts from the completion stage, checking conditions based on pre-defined rules, applying the recognition process corresponding to that stage, or moving to the immediately preceding stage if appropriate. The process ends when a new stage is identified and recorded into a spatio-temporal database or it reaches the previously detected stage as retrieved from the database. The experiment proved the effectiveness of the proposed framework, with an overall accuracy of about 80% and a low false detection rate. The proposed framework can be extended to monitor other similar scheduled works. Future studies will integrate multi-sensor satellite images including synthetic aperture radar images to expand further the practicality of the framework.     

Comparative analysis of starch properties of different root and tuber crops of Sri Lanka

The physicochemical properties of starches of six different root and tuber crop species grown mainly in Sri Lanka showed significant differences among the tested crop species and varieties. The median granule size of starch of tested root and tuber crop species varied from 33.5 to 10.2 μm. The largest granule size and the highest blue value were given by the canna, Buthsarana, and yam species, in that order. The amylose content of cassava was higher than those of sweet potato and many yams. High peak viscosities, high breakdown, and high final viscosities were observed in yams, and, generally, such starch showed a high swelling power. According to the correlation analysis, these pasting properties would mainly be due to their larger starch granule size. Based on the thermal properties, cassava starch showed less energy requirement for gelatinization and thus gelatinized at lower temperatures. Furthermore, a higher susceptibility of raw cassava starch toward fungal glucoamylase was observed. The low enzyme digestibility of raw yam starch would be due to its large granules. Correlation analysis showed that the blue value and starch granule size were important in determining the pasting, thermal, and other properties of starch.     

Extraction of HNO3 and some ions with tributyl phosphate (tbp)-mixed trialkyl phosphine oxides (trpo)/kerosene

Tributyl phosphate (TBP) and trialkyl phosphine oxides (TRPO) are important extractants. They are widely used in industrial extraction processes, especially in the nuclear power industry. However, both TBP and TRPO suffer from several disadvantages. TBP has a low extractability for trivalent transuranium elements such as Am³⁺ and Pu³⁺ while TRPO has low loading capacity for HNO₃ and UO₂ ²⁺. The extraction of HNO₃ and 20 other ions of importance in the nuclear power industry was studied using TBP-TRPO/kerosene. The loading capacity of UO₂ ²⁺ and HNO₃ in TBP-TRPO/kerosene was determined. The synergistic extraction characteristics of the mixture for Am³⁺ and TcO₄ m were studied. The influence of high-concentration UO₂ ²⁺ on the extraction of Am³⁺, Eu³⁺, Pu⁴⁺, and TcO₄ m was investigated. The experimental results show that TBP-TRPO/kerosene mixtures display both a high extractability for a number of ions and a high loading capacity for UO₂ ²⁺ and HNO₃.     

Raman spectroscopy and microscopy based on mechanical force detection

The Raman effect is typically observed by irradiating a sample with an intense light source and detecting the minute amount of frequency shifted scattered light. We demonstrate that Raman molecular vibrational resonances can be detected directly through an entirely different mechanism-namely, a force measurement. We create a force interaction through optical parametric down conversion between stimulated, Raman excited, molecules on a surface and a cantilevered nanometer scale probe tip brought very close to it. Spectroscopy and microscopy on clusters of molecules have been performed. Single molecules within such clusters are clearly resolved in the Raman micrographs. The technique can be readily extended to perform pump probe experiments for measuring inter- and intramolecular couplings and conformational changes at the single molecule level.     

Differential scanning tunnelling microscopy

We review the principle of differential imaging and its application to scanning tunnelling microscopy (STM). It is shown that placing a lateral dither on an STM tip at high frequency provides the means for transfering topographic information to a frequency range where noise is small. Differential STM imaging on graphite and gold is demonstrated. A simple relation between the differential image and the conventional topographic image is described.     

Contrast in reflection acoustic microscopy

Although the reflection acoustic microscope has long been used to study solid surfaces, the contrast that has been observed in images of complex i.c. devices were not well understood until fairly recently. Our recent article where we calculated the acoustic response of different materials suggested that the observed contrast was a strong function of the elastic properties of the surface being investigated. This letter is devoted to explaining the analysis used in our calculations.     

Bovine milk oligosaccharides decrease gut permeability and improve inflammation and microbial dysbiosis in diet-induced obese mice

Obesity is characterized by altered gut homeostasis, including dysbiosis and increased gut permeability closely linked to the development of metabolic disorders. Milk oligosaccharides are complex sugars that selectively enhance the growth of specific beneficial bacteria in the gastrointestinal tract and could be used as prebiotics. The aim of the study was to demonstrate the effects of bovine milk oligosaccharides (BMO) and Bifidobacterium longum ssp. infantis (B. infantis) on restoring diet-induced obesity intestinal microbiota and barrier function defects in mice. Male C57/BL6 mice were fed a Western diet (WD, 40% fat/kcal) or normal chow (C, 14% fat/kcal) for 7 wk. During the final 2 wk of the study, the diet of a subgroup of WD-fed mice was supplemented with BMO (7% wt/wt). Weekly gavage of B. infantis was performed in all mice starting at wk 3, yet B. infantis could not be detected in any luminal contents when mice were killed. Supplementation of the WD with BMO normalized the cecal and colonic microbiota with increased abundance of Lactobacillus compared with both WD and C mice and restoration of Allobaculum and Ruminococcus levels to that of C mice. The BMO supplementation reduced WD-induced increase in paracellular and transcellular flux in the large intestine as well as mRNA levels of the inflammatory marker tumor necrosis factor α. In conclusion, BMO are promising prebiotics to modulate gut microbiota and intestinal barrier function for enhanced health.