Structural health monitoring of railway tracks using IoT-based multi-robot system

Neural Computing and Applications - A multi-robot-based fault detection system for railway tracks is proposed to eliminate manual human visual inspection. A hardware prototype is designed to...     

Two-Color Capillary Electrophoresis with On-Column Excitation and Wave-Guide Based Fluorescent Detection

An optical wave-guide based two-color capillary electrophoresis laser induced fluorescence (CE-LIF) instrument is described. The wave-guide based approach allows for on column excitation and detection with two-color discrimination. The instrument is designed to allow either electrokinetic or hydrodynamic injections. In its present configuration, the attainable limit of detection (LOD, S/N = 3) was 50 X 10⁻²¹ moles of fluorescein with a 488-nm excitation source. This study was designed to test the instrument design for applications in protein analyses. Fluorescent dyes with two different wavelengths were simultaneously separated and detected as were complexes formed by labeled antibodies to NFκB p65 and cdc2p34. Quantification of both proteins in THP-1 cell lysates performed using this approach illustrates a rapid screening application of this instrument.     

Fabricating Strong and Stiff Bioplastics from Whole Spirulina Cells

Since the 1950s, 8.3 billion tonnes (Bt) of virgin plastics have been produced, of which around 5 Bt have accumulated as waste in oceans and other natural environments, posing severe threats to entire ecosystems. The need for sustainable bio-based alternatives to traditional petroleum-derived plastics is evident. Bioplastics produced from unprocessed biological materials have thus far suffered from heterogeneous and non-cohesive morphologies, which lead to weak mechanical properties and lack of processability, hindering their industrial integration. Here, a fast, simple, and scalable process is presented to transform raw microalgae into a self-bonded, recyclable, and backyard-compostable bioplastic with attractive mechanical properties surpassing those of other biobased plastics such as thermoplastic starch. Upon hot-pressing, the abundant and photosynthetic algae spirulina forms cohesive bioplastics with flexural modulus and strength in the range 3–5 GPa and 25.5–57 MPa, respectively, depending on pre-processing conditions and the addition of nanofillers. The machinability of these bioplastics, along with self-extinguishing properties, make them promising candidates for consumer plastics. Mechanical recycling and fast biodegradation in soil are demonstrated as end-of-life options. Finally, the environmental impacts are discussed in terms of global warming potential, highlighting the benefits of using a carbon-negative feedstock such as spirulina to fabricate plastics.     

Closed-Form Solution for System Availability Distribution

Highly reliable systems with long mission time, that can tolerate no down time, have motivated the study of system reliability. The emergence of fault-tolerant computing systems, where small down times may be tolerable, and preventive and corrective maintenance permitted, motivates a revisit to measures like mean availability. Vendors of computer systems are being required to specify the level of availability that will be met by their systems over a finite time interval, and pay a penalty for non-compliance. Since no closed-form solution has been reported in the literature, numerical approaches have often been used to compute systems availability over a finite time, even for simple Markov models. We report a Laplace transform solution for the distribution of availability over a finite interval, for a semi-Markov model. The transform of the distribution is analytically inverted to obtain a closed-form solution for the corresponding Markov model.     

Studies on swelling of cotton fibers in alkali metal hydroxides. I. Influence of variations in fine structure on tensile behavior

A study on cotton fibers swollen slack at ambient temperature in different concentrations of LiOH and KOH indicates that fibers swollen in KOH have higher disorder. Conversion to cellulose II results from swelling in both the reagents, although, with KOH swelling, it begins at a lower concentration. Further, retention of tenacity is higher at all gauge lengths after KOH swelling. Analysis of the influence of fine structure on tensile properties showed some specificity, mainly attributable to cationic size differences of the swelling agents.     

Segmentation and range sensing using a moving-aperture lens

The use of a novel motorized lens to perform segmentation of image sequences is presented in this paper. The lens has the effect of introducing small, repeating movements of the camera center so that objects appear to translate in the image by an amount that depends on the distance from the plane of focus. For a stationary scene, optical flow magnitudes are therefore directly related to three-dimensional object distance from the observer. We describe a segmentation procedure that exploits these controlled observer movements and present experimental results that demonstrate the successful extraction of objects at different depths. Potential applications of our approach include image compositing, teleconferencing, and range estimation.Received: 4 July 2002, Accepted: 16 December 2002, Published online: 23 July 2003 Correspondence to: Amy E. Bell     

Traditional Kerala style fish curry in indigenous retort pouch

Fish curry processed in metal cans is popular in the overseas markets. An important limitation with the use of metal cans is the undesirable taste imparted to the products on storage. Flexible pouches are an ideal alternative to metal cans. Extensive work carried out at Central Institute of Fisheries Technology has been able to identify indigenous pouches, which are as good as imported pouches. This has been done after collecting different types of indigenous and imported flexible pouches, analyzing their composition and conducting detailed studies on their physical and food contact application properties. Two indigenous pouches with composition 12 micron polyester/12 micron aluminium foil/87.5 micron cast polypropylene and 12 micron polyester/15 micron aluminium foil/70 micron cast polypropylene have been selected and got made by indigenous laminators and an imported one with configuration 12 micron polyester/15 micron aluminium foil/75 micron cast polypropylene were used for further experiment on processing fish curry. Traditional Kerala style mackerel fish curry was processed in the retort pouches of the above configurations. About 220 g fish curry was packed in each pouch (15.5 cm×7 cm). Process requirements were worked out by measuring heat penetration using thermocouples introduced into the pouches. Fish curry processed to a F₀ value of 8.43 gave an acceptable product with desired texture and sensory characteristics. The physical properties of the pouches studied showed that the indigenous pouches of the above configurations were good enough to give a shelf life of 1 year at room temperature. The curry remained sterile throughout the storage period at ambient temperature (25–30°C) and retained acceptable sensory characteristics.     

Role of molecular interactions and structural defects in the efficient fluorescence quenching by carbon nanotubes

Fluorescence quenching effect of single walled carbon nanotubes (SWCNTs) and multiwalled carbon nanotubes (MWCNTs) on three most common fluorophores fluorescein, rhodamine 6G and quinine sulphate has been studied and compared. Comparative studies of quenching efficiency shows that SWCNTs are more efficient fluorescence quencher than the MWCNTs. Nature of Stern–Volmer plot was found to be highly non-linear indicating combined effect of dynamic and static quenching. The contribution of dynamic quenching component was assessed through the fluorescence lifetime measurements. Studies on vacuum annealed SWCNTs with low defect contents suggest that structural defects primarily contribute to the large quenching. Fluorescence quenching was found to be dominant even in the cases where adsorption was low implying that surface adsorption play a minor role in the quenching, except for rhodamine 6G. Adsorption isotherms have been studied using Langmuir and Freundlich models. Freundlich model was found to be closer in behaviour implying a multilayer adsorption of molecules on the surface. The contributions of metal nanoparticles and carbon impurities present in different allotropic forms to the fluorescence quenching were also assessed. We speculate that defect mediated nonradiative energy transfer through dipole–dipole coupling may be the dominant mechanism of high efficiency quenching by SWCNTs.     

Thermal behavior and detonation properties of d3-hexanitrotrishomocubane

The DSC thermogram of the title compound (1) reveals the following characteristics: When a 3.34 mg sample of 1 was heated at 10°C-min^?1, exotherm onset occurred at 272°C, reached a maximum at 308°C, and subsided at 331°C. A second smaller exotherm was initiated at 331°C, reached a maximum at 338°C, and subsided at 355°C. A study of the shock sensitivity of 1 as measured by the exploding foil slapper technique revealed that 1 is less shock-sensitive than TNT. Explosive output calculations show that it is a substantially more powerful explosive than is TNT.     

Anomalies in hepatobiliary excretion of technetium-99m-MAG3 preparations

Technetium-99m-MAG3 is accepted as a renal tubular function agent. However, sporadic liver and gall bladder visualisation during its clinical use is clearly a disadvantage. HPLC-purified 99mTc-MAG3 samples exhibited appreciable hepatobiliary uptake (7%), and an elevated level of such uptake was observed in unpurified kit preparations, which was stated to be associated with the excretory property of the radiolabeled kit impurities. To verify this we attempted to quantitate the hepatobiliary uptake of the kit preparations with that of its radiolabeled components. The contribution of each component toward hepatobiliary uptake of the sample was calculated from their abundance in the chelate mixture and the individual biodistribution of the isolated components. However, the anticipated hepatobiliary uptake of different preparations of 99mTc-MAG3 calculated in this way was always lower than that of the experimental value determined directly. Further work is needed to explain the anomaly.