Methodology for measuring the vertical displacements of bridges using fibre bragg grating sensors

In many bridges, vertical displacements are one of the most relevant parameters for structural health monitoring in both the short- and long-terms. Bridge managers around the globe are always looking for a simple way to measure vertical displacements of bridges. However, it is difficult to carry out such measurements. On the other hand, in recent years, with the advancement of fibre-optic technologies, fibre Bragg grating (FBG) sensors are more commonly used in structural health monitoring due to their outstanding advantages including multiplexing capability, immunity of electromagnetic interference as well as high resolution and accuracy. For these reasons, a methodology for measuring the vertical displacements of bridges using FBG sensors is proposed. The methodology includes two approaches. One of which is based on curvature measurements while the other utilises inclination measurements from successfully developed FBG tilt sensors. A series of simulation tests of a full-scale bridge was conducted. It shows that both approaches can be implemented to measure the vertical displacements for bridges with various support conditions, varying stiffness along the spans and without any prior known loading. A static loading beam test with increasing loads at the mid-span and a beam test with different loading locations were conducted to measure vertical displacements using FBG strain sensors and tilt sensors. The results show that the approaches can successfully measure vertical displacements.

Epigenetic regulation of glucose transporters in non-small cell lung cancer

Due to their inherently hypoxic environment, cancer cells often resort to glycolysis, or the anaerobic breakdown of glucose to form ATP to provide for their energy needs, known as the Warburg effect. At the same time, overexpression of the insulin receptor in non-small cell lung cancer (NSCLC) is associated with an increased risk of metastasis and decreased survival. The uptake of glucose into cells is carried out via glucose transporters or GLUTs. Of these, GLUT-4 is essential for insulin-stimulated glucose uptake. Following treatment with the epigenetic targeting agents histone deacetylase inhibitors (HDACi), GLUT-3 and GLUT-4 expression were found to be induced in NSCLC cell lines, with minimal responses in transformed normal human bronchial epithelial cells (HBECs). Similar results for GLUT-4 were observed in cells derived from liver, muscle, kidney and pre-adipocytes. Bioinformatic analysis of the promoter for GLUT-4 indicates that it may also be regulated by several chromatin binding factors or complexes including CTCF, SP1 and SMYD3. Chromatin immunoprecipitation studies demonstrate that the promoter for GLUT-4 is dynamically remodeled in response to HDACi. Overall, these results may have value within the clinical setting as (a) it may be possible to use this to enhance fluorodeoxyglucose (18F) positron emission tomography (FDG-PET) imaging sensitivity; (b) it may be possible to target NSCLC through the use of HDACi and insulin mediated uptake of the metabolic targeting drugs such as 2-deoxyglucose (2-DG); or (c) enhance or sensitize NSCLC to chemotherapy. © 2011 by the authors; licensee MDPI, Basel, Switzerland.

The detection of incipient faults in small multi-cylinder diesel engines using multiple acoustic emission sensors

This thesis investigates condition monitoring (CM) of diesel engines using acoustic emission (AE) techniques. The AE signals recorded from a small size diesel engine are mixtures of multiple sources from multiple cylinders. Thus, it is difficult to interpret the information conveyed in the signals for CM purposes. This thesis develops a series of practical signal processing techniques to overcome this problem. Various experimental studies conducted to assess the CM capabilities of AE analysis for diesel engines. A series of modified signal processing techniques were proposed. These techniques showed promising results of capability for CM of multiple cylinders diesel engine using multiple AE sensors.

A preliminary study of the effects of Tai Chi and Qigong medical exercise on indicators of metabolic syndrome, glycaemic control, health-related quality of life, and psychological health in adults with elevated blood glucose

Objectives To evaluate the feasibility, acceptability and effects of a Tai Chi and Qigong exercise programme in adults with elevated blood glucose. Design, Setting, and Participants A single group pre–post feasibility trial with 11 participants (3 male and 8 female; aged 42–65 years) with elevated blood glucose. Intervention Participants attended Tai Chi and Qigong exercise training for 1 to 1.5 h, 3 times per week for 12 weeks, and were encouraged to practise the exercises at home. Main Outcome Measures Indicators of metabolic syndrome (body mass index (BMI), waist circumference, blood pressure, fasting blood glucose, triglycerides, HDL-cholesterol); glucose control (HbA1c, fasting insulin and insulin resistance (HOMA)); health-related quality of life; stress and depressive symptoms. Results There was good adherence and high acceptability. There were significant improvements in four of the seven indicators of metabolic syndrome including BMI (mean difference −1.05, p<0.001), waist circumference (−2.80 cm, p<0.05), and systolic (−11.64 mm Hg, p<0.01) and diastolic blood pressure (−9.73 mm Hg, p<0.001), as well as in HbA1c (−0.32%, p<0.01), insulin resistance (−0.53, p<0.05), stress (−2.27, p<0.05), depressive symptoms (−3.60, p<0.05), and the SF-36 mental health summary score (5.13, p<0.05) and subscales for general health (19.00, p<0.01), mental health (10.55, p<0.01) and vitality (23.18, p<0.05). Conclusions The programme was feasible and acceptable and participants showed improvements in metabolic and psychological variables. A larger controlled trial is now needed to confirm these promising preliminary results.

Towards discrimination of challenging conditions for UGVs with visual and infrared sensors

This work aims to contribute to reliability and integrity in perceptual systems of autonomous ground vehicles. Information theoretic based metrics to evaluate the quality of sensor data are proposed and applied to visual and infrared camera images. The contribution of the proposed metrics to the discrimination of challenging conditions is discussed and illustrated with the presence of airborne dust and smoke.

Error modeling and calibration of exteroceptive sensors for accurate mapping applications

Reliable robotic perception and planning are critical to performing autonomous actions in uncertain, unstructured environments. In field robotic systems, automation is achieved by interpreting exteroceptive sensor information to infer something about the world. This is then mapped to provide a consistent spatial context, so that actions can be planned around the predicted future interaction of the robot and the world. The whole system is as reliable as the weakest link in this chain. In this paper, the term mapping is used broadly to describe the transformation of range-based exteroceptive sensor data (such as LIDAR or stereo vision) to a fixed navigation frame, so that it can be used to form an internal representation of the environment. The coordinate transformation from the sensor frame to the navigation frame is analyzed to produce a spatial error model that captures the dominant geometric and temporal sources of mapping error. This allows the mapping accuracy to be calculated at run time. A generic extrinsic calibration method for exteroceptive range-based sensors is then presented to determine the sensor location and orientation. This allows systematic errors in individual sensors to be minimized, and when multiple sensors are used, it minimizes the systematic contradiction between them to enable reliable multisensor data fusion. The mathematical derivations at the core of this model are not particularly novel or complicated, but the rigorous analysis and application to field robotics seems to be largely absent from the literature to date. The techniques in this paper are simple to implement, and they offer a significant improvement to the accuracy, precision, and integrity of mapped information. Consequently, they should be employed whenever maps are formed from range-based exteroceptive sensor data. © 2009 Wiley Periodicals, Inc.

Damage evaluation based on a wave energy flow map using multiple PZT sensors

A new wave energy flow (WEF) map concept was proposed in this work. Based on it, an improved technique incorporating the laser scanning method and Betti’s reciprocal theorem was developed to evaluate the shape and size of damage as well as to realize visualization of wave propagation. In this technique, a simple signal processing algorithm was proposed to construct the WEF map when waves propagate through an inspection region, and multiple lead zirconate titanate (PZT) sensors were employed to improve inspection reliability. Various damages in aluminum and carbon fiber reinforced plastic laminated plates were experimentally and numerically evaluated to validate this technique. The results show that it can effectively evaluate the shape and size of damage from wave field variations around the damage in the WEF map.

Ultrasensitive strain sensors made from metal-coated carbon nanofiller/epoxy composites

A set of resistance-type strain sensors has been fabricated from metal-coated carbon nanofiller (CNF)/epoxy composites. Two nanofillers, i.e., multi-walled carbon nanotubes and vapor growth carbon fibers (VGCFs) with nickel, copper and silver coatings were used. The ultrahigh strain sensitivity was observed in these novel sensors as compared to the sensors made from the CNFs without metal-coating, and conventional strain gauges. In terms of gauge factor, the sensor made of VGCFs with silver coating is estimated to be 155, which is around 80 times higher than that in a metal-foil strain gauge. The possible mechanism responsible for the high sensitivity and its dependence with the networks of the CNFs with and without metal-coating and the geometries of the CNFs were thoroughly investigated.

Methanesulfonic acid-catalyzed conversion of glucose and xylose mixtures to levulinic acid and furfural

Methanesulfonic acid (MSA) was compared with sulfuric acid for the conversion of glucose and xylose mixtures to produce levulinic acid and furfural. The interactions of glucose and xylose, the predominant sugars found in biomass, were found to influence product yields with furfural degradation reactions enhanced under higher reactant loadings. Fast heating rates allowed maximal yields (>60 mol%) of levulinic acid and furfural to be achieved under short reaction times. Under the range of conditions examined, sulfuric acid produced a slight increase in levulinic acid yield by 6% (P = 0.02), although there was no significant difference (P = 0.11) between MSA and sulfuric acid in levulinic acid formed from glucose alone. The amount and type of the solid residue is similar between MSA and sulfuric acid. As such, MSA is a suitable alternative because its use minimizes corrosion and disposal issues associated with mineral acid catalysts. The heating value of the residue was 22 MJ/kg implying that it is a suitable source of fuel. On the basis of these results, a two-stage processing strategy is proposed to target high levulinic acid and furfural yields, and other chemical products (e.g., lactic acid, xylitol, acetic acid and formic acid). This will result in full utilization of bagasse components.

Conductometric gas sensors based on nanostrutured WO3 thin films

Nanostructured WO3 thin films have been prepared bythermal evaporation to detect hydrogen at low t emperatures. The influence of heat treatment on the physical, chemical and electronic properties of these films has been investigated. The films were annealed at 400oC for 2 hours in air. AFM and TEM analysis revealed that the as-deposited WO3 film is high amorphous and made up of cluster of particles. Annealing at 400oC for 2 hours in air resulted in very fine grain size of the order of 5 nm and porous structure. GIXRD and Raman analysis revealed that annealing improved the crystallinity of WO3 film. Gas sensors based on annealed WO3 films have shown a high response towards various concentrations (10-10000 ppm) H2 at an operating temperature of 150oC. The improved sensing performance at low operating temperature is due to the optimum physical, chemical and electronic properties achieved in the WO3 film through annealing. - See more at: http://dl4.globalstf.org/?wpsc-product=conductometric-gas-sensors-based-on-nanostructured-wo3-thin-films-2#sthash.IrfhlZ6H.dpuf

Nb2O5 Schottky based ethanol vapour sensors : effect of metallic catalysts

The aim of this paper is to compare the performances of the highly porous Nb2O5 Schottky based sensors formed using different catalytic metals for ethanol vapour sensing. The fabricated sensors consist of a fairly ordered nano-vein like porous Nb2O5 prepared via an elevated temperature anodization method. Subsequently, Pt, Pd and Au were sputtered as both Schottky contacts and catalysts for the comparative studies. These metals are chosen as they have large work functions in comparison to the electron affinity of the anodized Nb2O5. It is demonstrated that the device based on Pd/Nb2O5 Schottky contact has the highest sensitivity amongst the developed sensors. The sensing behaviors were studied in terms of the Schottky barrier height variations and properties of the metal catalysts.

Vertical displacement measurement using fibre Bragg grating (FBG) sensors for structural health monitoring of bridges

This thesis developed a practical, cost effective, easy-to-use method for measuring the vertical displacements of bridges using fiber Bragg grating (FBG) sensors, which includes the curvature and inclination approaches. These approaches were validated by the numerical simulation tests on a full scale bridge and the laboratory-based tests. In doing so, a novel frictionless FBG inclination sensor with extremely high sensitivity and resolution has also been developed and validated.

Vertical graphene gas- and bio-sensors via catalyst-free, reactive plasma reforming of natural honey

A rapid reforming of natural honey exposed to reactive low-temperature Ar + H2 plasmas produced high-quality, ultra-thin vertical graphenes, without any metal catalyst or external heating. This transformation is only possible in the plasma and fails in similar thermal processes. The process is energy-efficient, environmentally benign, and is much cheaper than common synthesis methods based on purified hydrocarbon precursors. The graphenes retain the essential minerals of natural honey, feature reactive open edges and reliable gas- and bio-sensing performance.

Highly NO2 sensitive caesium doped graphene oxide conductometric sensors

Here we report on the synthesis of caesium doped graphene oxide (GO-Cs) and its application to the development of a novel NO2 gas sensor. The GO, synthesized by oxidation of graphite through chemical treatment, was doped with Cs by thermal solid-state reaction. The samples, dispersed in DI water by sonication, have been drop-casted on standard interdigitated Pt electrodes. The response of both pristine and Cs doped GO to NO2 at room temperature is studied by varying the gas concentration. The developed GO-Cs sensor shows a higher response to NO2 than the pristine GO based sensor due to the oxygen functional groups. The detection limit measured with GO-Cs sensor is ≈90 ppb.

The impact of prolonged hyperinsulinaemia on glucose transport in equine skeletal muscle and digital lamellae

REASONS FOR PERFORMING STUDY An increased incidence of metabolic disease in horses has led to heightened recognition of the pathological consequences of insulin resistance (IR). Laminitis, failure of the weight-bearing digital lamellae, is an important consequence. Altered trafficking of specialised glucose transporters (GLUTs) responsible for glucose uptake, are central to the dysregulation of glucose metabolism and may play a role in laminitis pathophysiology. OBJECTIVES We hypothesised that prolonged hyperinsulinaemia alters the regulation of glucose transport in insulin-sensitive tissue and digital lamellae. Our objectives were to compare the relative protein expression of major GLUT isoforms in striated muscle and digital lamellae in healthy horses and during hyperinsulinaemia. STUDY DESIGN Randomised, controlled study. METHODS Prolonged hyperinsulinaemia and lamellar damage were induced by a prolonged-euglycaemic hyperinsulinaemic clamp (p-EHC) or a prolonged-glucose infusion (p-GI) and results were compared to electrolyte-treated controls. GLUT protein expression was examined with immunoblotting. RESULTS Lamellar tissue contained more GLUT1 protein than skeletal muscle (p = 0.002) and less GLUT4 than the heart (p = 0.037). During marked hyperinsulinaemia and acute laminitis (induced by the p-EHC), GLUT1 protein expression was decreased in skeletal muscle (p = 0.029) but unchanged in the lamellae, while novel GLUTs (8; 12) were increased in the lamellae (p = 0.03), but not skeletal muscle. However, moderate hyperinsulinaemia and subclinical laminitis (induced by the p-GI) did not cause differential GLUT protein expression in the lamellae vs. control horses. CONCLUSIONS The results suggest that lamellar tissue functions independently of insulin and that IR may not be an essential component of laminitis aetiology. Marked differences in GLUT expression exist between insulin-sensitive and insulin-independent tissues during metabolic dysfunction in horses. The different expression profiles of novel GLUTs during acute and subclinical laminitis may be important to disease pathophysiology and require further investigation.