Passive low frequency RFID for non-destructive evaluation and monitoring

Ph. D ThesisDespite of immense research over the years, defect monitoring in harsh environmental conditions still presents notable challenges for Non-Destructive Testing and Evaluation (NDT&E) and Structural Health Monitoring (SHM). One of the substantial challenges is the inaccessibility to the metal surface due to the large stand-off distance caused by the insulation layer. The hidden nature of corrosion and defect under thick insulation in harsh environmental conditions may result in it being not noticed and ultimately leading to failures. Generally electromagnetic NDT&E techniques which are used in pipeline industries require the removal of the insulation layer or high powered expensive equipment. Along with these, other limitations in the existing techniques create opportunities for novel systems to solve the challenges caused by Corrosion under Insulation (CUI). Extending from Pulsed Eddy Current (PEC), this research proposes the development and use of passive Low Frequency (LF) RFID hardware system for the detection and monitoring of corrosion and cracks on both ferrous and non-ferrous materials at varying high temperature conditions. The passive, low cost essence of RFID makes it an enchanting technique for long term condition monitoring. The contribution of the research work can be summarised as follows: (1) implementation of novel LF RFID sensor systems and the rig platform, experimental studies validating the detection capabilities of corrosion progression samples using transient feature analysis with respect to permeability and electrical conductivity changes along with enhanced sensitivity demonstration using ferrite sheet attached to the tag; (2) defect detection using swept frequency method to study the multiple frequency behaviour and further temperature suppression using feature fusion technique; (3) inhomogeneity study on ferrous materials at varying temperature and demonstration of the potential of the RFID system; (4) use of RFID tag with ceramic filled Poly-tetra-fluoro-ethyulene (PTFE) substrate for larger applicability of the sensing system in the industry; (5) lift-off independent defect monitoring using passive sweep frequency RFID sensors and feature extraction and fusion for robustness improvement. This research concludes that passive LF RFID system can be used to detect corrosion and crack on both ferrous and non-ferrous materials and then the system can be used to compensate for temperature variation making it useful for a wider range of applications. However, significant challenges such as permanent deployment of the tags for long term monitoring at higher temperatures and much higher standoff distance, still require improvement for real-world applicability.Engineering and Physical Sciences Research Council (EPSRC) CASE, National Nuclear Laboratory (NNL)

Diagnosis and management of osteoporosis in the older senior

The older senior is at high risk for osteoporosis. It is important for healthcare providers to be fully aware of the potential risks and benefits of diagnosing and treating osteoporosis in the older senior population. Data indicate that bone mineral density testing is under-utilized and drug therapy is often not initiated when indicated in this population. Bone mineral density testing with central dual energy x-ray absorptiometry is essential and cost-effective in this population. All older seniors should be educated on a bone-healthy lifestyle including age-appropriate weight-bearing exercise and smoking cessation if necessary. It is important to remember that falls play a very important role in the risk for osteoporotic fractures, especially in the older senior. All older seniors should be evaluated annually for falls and strategies should be implemented to reduce fall risk in this population. The risk for vitamin D insufficiency and deficiency is high in the older senior and can contribute to falls and fractures. Adequate intakes of calcium and vitamin D are important and deficiencies need to be treated. Data on osteoporosis drug therapy in the older senior are lacking. Based on data from subgroup analyses of large osteoporosis trials in postmenopausal women, current osteoporosis therapies appear safe and efficacious in the older senior and most will live long enough to derive a benefit from these therapies. Further studies are needed in older seniors, especially men, to better understand the risks and benefits of pharmacologic therapy for the management of osteoporosis

Economic burden of diabetes mellitus and its socio-economic impact on household expenditure in an urban slum area

Background: India is on the brink of an epidemic of diabetes mellitus (DM). In the near future, DM will pose a severe burden on the already fragile and under-resourced health care system in India.Methods: A prospective community based cohort study was taken up for assessing the financial burden on households of patients with DM in an urban slum of Mumbai to reflect the economic implications of DM.Results: The mean age of participants was 51 years. Forty (33.33%) out of 120 were suffering from diabetes for more than 5 years and it was proved statistically that the total cost of expenditure on treatment per month was significantly related to the duration of DM. On an average the monthly direct expenditure was INR 687.5 per patient and indirect expenditure was INR 348.75 per patient. Catastrophic expenditure was borne by 5.8% of the participants.Conclusions: Direct cost forms the major component of the total cost of DM management. The expenditure on the management of Diabetes increases with the duration of the illness. As the out-of-pocket expenditure is the mainstay of financing the cost of diabetes mellitus in India, there is a possibility of these households of DM patients might be pushed into the poverty trap. It is recommended that the Government facilities for management of DM should be strengthened and quality of services should be improved in the interest of diabetic patients. Public awareness campaigns about the economic implications of DM and services provided by the government should be carried out

Children exposed to intimate partner violence: Identifying differential effects of family environment on children\u27s trauma and psychopathology symptoms through regression mixture models

The majority of analytic approaches aimed at understanding the influence of environmental context on children\u27s socioemotional adjustment assume comparable effects of contextual risk and protective factors for all children. Using self-reported data from 289 maternal caregiver-child dyads, we examined the degree to which there are differential effects of severity of intimate partner violence (IPV) exposure, yearly household income, and number of children in the family on posttraumatic stress symptoms (PTS) and psychopathology symptoms (i.e., internalizing and externalizing problems) among school-age children between the ages of 7–12 years. A regression mixture model identified three latent classes that were primarily distinguished by differential effects of IPV exposure severity on PTS and psychopathology symptoms: (1) asymptomatic with low sensitivity to environmental factors (66% of children), (2) maladjusted with moderate sensitivity (24%), and (3) highly maladjusted with high sensitivity (10%). Children with mothers who had higher levels of education were more likely to be in the maladjusted with moderate sensitivity group than the asymptomatic with low sensitivity group. Latino children were less likely to be in both maladjusted groups compared to the asymptomatic group. Overall, the findings suggest differential effects of family environmental factors on PTS and psychopathology symptoms among children exposed to IPV. Implications for research and practice are discussed

Data on cost analysis of drilling mud displacement during drilling operation

The focus of this research was to present a data article for analyzing the cost of displacing a drilling fluid during the drilling operation. The cost of conventional Spud, KCl and Pseudo Oil base (POBM) muds used in drilling oil and gas wells are compared with that of a Reversible Invert Emulsion Mud.The cost analysis islimited tothree sections for optimum and effective Comparison. To optimize drilling operations, it is important that we specify the yardstick by which drilling performance is measured. The most relevant yardstick is the cost per foot drilled.The datahave shown thatthe prices fordrilling mud systems are a function of the mud system formulation cost for that particular mud weight and maintenance per day. These costs for different mud systems and depend on the base fluid. The Reversible invert emulsion drilling fluid, eliminates the cost acquired in displacing Pseudo Oil Based mud (POBM) from the well, possible formation damage (permeability impairment) resulting from the use of viscous pill in displacing the POBM from the wellbore, and also eliminates the risk of taking a kick during mud change-over. With this reversible mud system, the costs of special fluids that are rarely applied for the well-completion purpose (cleaning of thick mud filter cake) may be reduced to the barest minimum

Dark energy in light of the early JWST observations: case for a negative cosmological constant?

Early data from the James Webb Space Telescope (JWST) has uncovered the existence of a surprisingly abundant population of very massive galaxies at extremely high redshift, which are hard to accommodate within the standard $\Lambda$CDM cosmology. We explore whether the JWST observations may be pointing towards more complex dynamics in the dark energy (DE) sector. Motivated by the ubiquity of anti-de Sitter vacua in string theory, we consider a string-inspired scenario where the DE sector consists of a negative cosmological constant (nCC) and a evolving component with positive energy density on top, whose equation of state is allowed to cross the phantom divide. We show that such a scenario can drastically alter the growth of structure compared to $\Lambda$CDM, and accommodate the otherwise puzzling JWST observations if the dynamical component evolves from the quintessence-like regime in the past to the phantom regime today: in particular, we demonstrate that the presence of a nCC (which requires a higher density for the evolving component) plays a crucial role in enhancing the predicted cumulative comoving stellar mass density. Our work reinforces the enormous potential held by observations of the abundance of high-$z$ galaxies in probing cosmological models and new fundamental physics, including string-inspired ingredients.Comment: 30 pages, 10 sub-figures arranged into 5 figures. v2: additional references added, acknowledgements updated. v3: added two sub-figures (one additional figure) and additional references. Version accepted for publication in JCA

Low-threshold BBO OPO with cylindrical focusing

The design of a BBO OPO cavity based on cylindrical focusing of the pump beam in the insensitive plane of the non-linear crystal is presented and characterized. A variety of beam sizes in the sensitive plane of the BBO crystal are investigated, and in all cases this cavity design is found to significantly lower the operational threshold pulse energy of 355 nm pumped type I BBO OPOs. With optimal beam focussing parameters, the measured threshold intensity of 45 MW/cm^2 is similar to that of conventional OPOs, but the threshold pulse energy of 0.4 mJ is some twenty times lower than that found in circularly symmetric pump beams. Pump pulse energies in this range can now be routinely achieved with diode-pumped Q-switched lasers, and the combination of these sources with cylindrically-focussed OPO cavities should result in a new class of all-solid-state high repetition rate and high average power non-linear light sources that can be tuned over the entire visible wavelength region

Characteristic trace fossils from Miocene brackish- water deposits in the Niger Delta, Nigeria

Miocene deposits in the eastern portion of the Greater Ughelli, Central Swamp and Coastal Swamp depobelts contain well-developed brackish-water trace fossil assemblages. Twelve ichnogenera have been identified, namely: Asterosoma, Bergaueria, Chondrites, Gyrolithes, Thalassinoides, Lockeia, Palaeophycus, ?Conichnus, Planolites, Siphonichnus, Skolithos and Diplocraterion. In addition, common non-descript, passively filled burrows and fugichnia (escape structures) have also been observed. The above-mentioned ichnogenera and associated non-descript structures can be arranged into six distinct and recurring ichnoassociations within the Greater Ughelli, Central Swamp and Coastal Swamp depobelts. Each ichnoassociation is comprised of a group of trace fossils which collectively reflect specific environmental conditions during deposition of these Miocene strata. All trace fossil assemblages illustrate deposition in nearshore, restricted settings. Ichnological and sedimentological criteria which may be utilized to recognise brackish-water deposits are discussed and illustrated in pictures of the cores studied