This research focuses on the creation, validation, automation, and deployment of a nondestructive vertical electrical impedance (VEI) bridge deck assessment apparatus. A multichannel impedance analyzer with a moving platform is developed that can assess the deterioration state of a bridge deck without stationary traffic control. The multichannel apparatus is capable of taking over 500 impedance samples a second and can scan a bridge deck over 500 times faster than more traditional techniques. This research also shows VEI measurements are inversely proportional to the diffusivity of ions through concrete and that an impedance measurement frequency of 25 kHz is the most predictive measurement frequency of diffusivity. Finally, this research demonstrates the utility of VEI measurements by inspecting five asphalt overlaid bridges. VEI measurements were sensitive to defects in membranes and are one of the only nondestructive measurements that provide useful information about the deterioration state of asphalt overlaid bridge decks.

This research was originally conceived under the auspices of the UK Government's Foresight Initiative, which aimed to translate the significant body of process tomography knowledge, residing in various British universities, towards applications of generic benefit to industry. In collaboration with the sponsoring life science company, Zeneca Ltd, a number of potential demonstrator projects were identified. Ultimately on-line imaging within pressure filtration was selected by virtue of its direct and broad benefit to the chemical sector and the opportunity to extrapolate the techniques developed towards other batch production processes. The research programme is centred around three empirical studies. These progress from an initial phase, where the early laboratory instrumentation was exposed to a constrained set of filtration conditions, through to the installation of a novel prototype industrial tomography system on to an existing large scale production unit, which was fabricated from an electrically conducting alloy and located in a potentially flammable atmosphere. During the course of these investigations electrical impedance tomography (EIT) was identified as the most viable modality for this class of application. The challenges associated with transferring the EIT technology into the manufacturing environment were addressed by taking advantage of the lenient frame rates acceptable within chemical batch monitoring to develop an instrument structure which was intrinsically safe, suitable for use with earthed metal vessels, tolerant to chemically aggressive media and amenable to three-dimensional image reconstruction via irregular, process compliant, electrode architectures. In the subject production filter a planar sensor array was exploited to provide a relatively uniform electrical field distribution within the process material, whilst not adversely affecting the normal operation of the plant item.

Electrical impedance is the frequency domain ratio of the voltage to the current. Electrical impedance extends the concept of resistance to AC circuits, describing not only the relative amplitudes of the voltage and current, but also the relative phases. Many new generation impedance measuring instruments measure the real and imaginary part of the impedance vector.Textile sensors are becoming an emerging field in industry. The possibilities that this technology holds seem almost limitless. Currently, textiles are being developed for many applications and markets, including biomedical sensing, wearable computing, large area sensors and large area actuating devices.A novel concept for a textile sensor for detection of moisture surroundings The sensor has been theoretically analysis. The results of the developed sensor shows less resistance drop characteristics against sweat.

Mechanical ventilation is vital for the treatment of patients in respiratory intensive care and can be life saving. However, the risks of regional pressure gradients and over-distension must be balanced with the need to maintain function. For these reasons mechanical ventilation can benefit from the regional information provided by bedside imaging such as electrical impedance tomography (EIT). In this thesis we develop and test methods to retrieve clinically meaningful measures of lung function from EIT and examine the feasibility of closing the feedback loop to enable EIT-guided control of mechanical ventilation. Working towards this goal we develop a reconstruction algorithm capable of providing fast absolute values of conductivity from EIT measurements. We couple the resulting conductivity time series to a compartmental ordinary differential equation (ODE) model of lung function in order to recover regional parameters of elastance and airway resistance. We then demonstrate how these parameters may be used to generate optimised pressure controls for mechanical ventilation that expose the lungs to minimal gradients of pressure and are stable with respect to EIT measurement errors. The EIT reconstruction algorithm we develop is capable of producing low dimensional absolute values of conductivity in real time after a limited additional setup time. We show that this algorithm retains the ability to give fast feedback on regional lung changes. We also describe methods of improving computational efficiency for general Gauss-Newton type EIT algorithms. In order to couple reconstructed conductivity time series to our ODE model we describe and test the recovery of regional ventilation distributions through a process of regularised differentiation. We prove that the parameters of our ODE model are recoverable from these ventilation distributions apart from the degenerate case where all compartments have the same parameters. We then test this recovery process under varying levels of simulated EIT measurement and modelling errors. Finally we examine the ODE lung model using control theory. We prove that the ODE model is controllable for a wide range of parameter values and link controllability to observable ventilation patterns in the lungs. We demonstrate the generation and optimisation of pressure controls with minimal time gradients and provide a bound on the resulting magnitudes of these pressures. We then test the control generation process using ODE parameter values recovered through EIT simulations at varying levels of measurement noise. Through this work we have demonstrated that EIT reconstructions can be of benefit to the control of mechanical ventilation.

As variation in pork tenderness has increased, identification of tenderness has become an industry need. This study consisted of 1208 pork loins randomly selected to test the efficacy of four automated grading techniques. Visible and near-infrared spectroscopy (VVNIR) (350-1830 nm wavelengths), bioelectrical impedance (EI) (resistance, reactance, phase angle, and partial capacitance), pH, and CIE L*, a* and b* color space values were used to predict chemical moisture and lipid, pH, Warner-Bratzler shear force (WBSF), and Slice shear force (SSF) on 13 d aged pork loins. The means and standard deviations for WBSF were (22.95 and 5.16) and SSF were (165.49 and 58.15). Prediction was based on stepwise linear regression and partial least squares regression. VNIR, pH, and color, when in combination, had the highest R^2 (0.19 and 0.21) for the prediction of WBSF and SSF, respectively. Partial least squares regression (PLSR) was used to remove autocorrelation between VNIR values. By using PLSR, with an R ^2 value of 0.49, 100 percent of the "tender" chops were correctly classified, 93 percent of the "intermediate" chops were correctly classified, and 92 percent of the "tough" chops were correctly classified into its category for WBSF. However, SSF was much lower (R^2 = 0.24) with only correctly placing 62 percent of the "tender" chops and only 48 percent of the "intermediate" and "tough" chops. Electrical impedance, alone or in combination with other technologies, either did not improve predictability of linear regression equations (increase R^2) or of PLSR models (increase R^2). Equations and models that included EI values had low R^2. When adding EI to the regression equation involving all variables, R^2 increased slightly from 0.19 to 0.21 in predicting WBSF, and from 0.21 to 0.25 for SSF. When pH or CIE L* color space values were included in linear regression or PLSR models to predict WBSF and SSF, R^2 values increased from 0.14 to 0.19 for WBSF, and 0.14 to 0.21 for SSF. pH played a large role in predicting WBSF and SSF, along with CIE L*. Thus, for an on-line situation, use of VNIR, pH, and color could be used to predict tenderness. Utilization of VNIR alone could be effective in predicting pork tenderness (WBSF). Using EI alone, or in combination with VNIR, would not provide acceptable prediction of WBSF or SSF. Use of VNIR with pH and color would improve the ability to predict tender and intermediate pork WBSF and SSF, but the additional improvement in accuracy may not be warranted based on the cost and additional time needed when using more than one technology.

Thesis (Ph. D.)--University of Texas at Austin, 1998. / Vita. Includes bibliographical references (leaves 184-191). Available also in a digital version from Dissertation Abstracts.

Thesis--Lund Institute of Technology, 1994.

Thesis--Lund Institute of Technology, 1994.

Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (leaves 112-124).

Graphite bricks make up a significant part of the core of an Advanced Gas-cooled Reactor (AGR). The graphite moderates the neutrons vital to the continuation of the fission chain reaction and provides support and stability for the entire core. During operation, the graphite can be oxidised due to the extreme conditions inside the core and so undergo weight loss. Differential shrinkage caused by neutron interaction throughout the brick can also cause radial cracking to occur. The effects of the oxidation, weight loss and cracking reduce the ability of the graphite to function as a moderator. The effects also have the potential of reducing the structural integrity of the brick, causing movement and structural instability of the entire core. It is, therefore, vital to monitor the condition of the graphite bricks and to understand how the changes in the graphite's properties and structure may affect the safe operation of the reactor. This report firstly looks briefly at the effect of irradiation on the graphite brick; the mechanisms leading to weight loss and cracking. The report then considers various methods which can be used to inspect the deterioration of graphite blocks within the cores of AGRs deriving quantitative and qualitative information on density and crack profiling. These methods will be considered for use both on small samples trepanned from the core and in-situ blocks within the reactor core, requiring non-destructive techniques. The inspection methods considered in this report are: Electrical Impedance Tomography (EIT); Four point probes; Eddy Current Tomography; and Electromagnetic Inductance Tomography (EMT).There are two main contributions of this thesis. First, the development an EIT methodology using outward facing probes, which were best suited to the geometry of the graphite bricks within the AGR. Proof of principle was established using both modelling and laboratory testing. The second contribution is the development of commercial grade EMT equipment, which can be used on-site to determine the conductivity of trepanned samples. The method was successfully demonstrated in the laboratory; however, further development will be required for use on-site, due to the sampling speed required.