Power Processing for Electrostatic Microgenerators

Microgenerators are electro-mechanical devices which harvest energy from local environmental from such sources as light, heat and vibrations. These devices are used to extend the life-time of wireless sensor network nodes. Vibration-based microgenerators for biomedical applications are investigated in this thesis. In order to optimise the microgenerator system design, a combined electro-mechanical system simulation model of the complete system is required. In this work, a simulation toolkit (known as ICES) has been developed utilising SPICE. The objective is to accurately model end-to-end microgenerator systems. Case-study simulations of electromagnetic and electrostatic microgenerator systems are presented to verify the operation of the toolkit models. Custom semiconductor devices, previously designed for microgenerator use, have also been modelled so that system design and optimisation of complete microgenerator can be accomplished. An analytical framework has been developed to estimate the maximum system effectiveness of an electrostatic microgenerator operating in constant-charge and constant-voltage modes. The calculated system effectiveness values are plotted with respect to microgenerator sizes for different input excitations. Trends in effectiveness are identified and discussed in detail. It was found that when the electrostatic transducer is interfaced with power processing circuit, the parasitic elements of the circuit are reducing the energy generation ability of the transducer by sharing the charge during separation of the capacitor plates. Also, found that in constant-voltage mode the electrostatic microgenerator has a better effectiveness over a large operating range than constant-charge devices. The ICES toolkit was used to perform time-domain simulation of a range of operating points and the simulation results provide verification of the analytical results

On-Metal Synthesis of Some Aryl Substituted Rhenium &#951\u3csup\u3e5\u3c/sup\u3e Cyclopenta[C] Pyridazyl Complexes

Heterocyclic organic and organometallic compounds (e.g. polypyrrole) and their derivatives have been of great interest for conductive polymers due to their novel properties and environmental stability as compared to non-aromatic analogs (e.g. polyacetylene). We are interested in synthesizing organometallic pyridazines and rhenium pyridazyl complexes for polymer research. SeveraI5,6-fused ring pyridazines (1,2-CsH3(CRNH)(CRN) have been synthesized and characterized. Additionally, pyridazyl complexes of rhenium were synthesized in three steps beginning from fulvenes 1,2-CsH3(COHR)(COR). On-Metal synthesis and characterization of (Re(CO)3 {1,2- CSH3(CRN)(CRN)}] (R=C6RtOMe, C6RtCI, C4H30) and some off-metal pyridazines are reported here. Our research is focused on synthesis of a variety of 5,6- fused ring pyridazines which will serve as synthetic models and building blocks for organic and organometallic conducting polymers. Our research focused on synthesis of 5 membered pyridazines and their organometallic rhenium complexes for polymer studies. Several aryl-substituted 5,6- fused ring pyridazines have been synthesized and characterized

Bidding model for sustainable projects using the traditional procurement method

The evolving concept of sustainable development introduced a new dimension to development processes and procurement routes. Consumption of natural raw materials that have fixed quantity without commensurate replacement should be a matter of concern to humanity. The need to maintain the ever growing human populace instigates the challenge that society’s developmental effort meets the demand of economic prudence, social equity and environmental conservation. This is quite daunting one, yet must be met if this planet earth and its inhabitants are not to be put in harm’s way. Sustainability in development seeks to achieve the reduction of input-output ratio yet presenting qualitative and satisfactory products to end users. The traditional procurement method (TPM) is still widely used in construction because of some advantages it offers over other methods. Contractor selection in the traditional procurement method can no longer be overlooked- being a vital process that influences project success in terms of cost, quality, function, and environmental care. Many scholars have asserted that time allowed for bidding in the TPM is little in Nigeria as such responsible for the persistent cost over-run in building construction projects. Increasing the time increases the overall project procurement period. Since market fluctuation due to other market forces is unfriendly, the goal of sustainable projects is defeated in this context. This paper seeks to enquire if the TPM remains a good base for project procurement and then modified to retain its numerous advantages over its disadvantages. Estimates from 50 samples of projects were tested using analysis of variance (ANOVA) to find if the (estimates) are reliable at times of tender. This was established and a new bidding model using the TPM proposed. The model reduced time taken to bid yet gave bidders more time to prepare their offer. Other critiques of the TPM have also been addressed in the model. This helps to achieve the goal of sustainable development and enhances TPM for built environment

INDIRECT SPECTROPHOTOMETRIC ESTIMATION OF DRUGS USING CERIUM (IV) AND RHODAMINE-B AS ANALYTICAL REAGENT

Objective: The object of this research was to develop simple, sensitive and selective methods for the quantitative determination of five drugs, viz., (RAM) Ramipril, (VOR) Voriconazole, (SDC) Sildenafil Citrate, (ITM) Imatinib mesylate and (CFH) Ciprofloxacin hydrochloride.Methods: The method for each drug depends upon oxidation of drugs by Cerium [Ce (IV)] (Excess) and estimating the amount of unreacted Ce (IV) by Rhodamine-B dye at 557 nm. These methods have been applied to the determination of drugs in their pure form as well as in tablet formulations.Results: Beer's law is obeyed in the concentration of 16-112, 15-105, 12-84, 8-56 and 2-14 μg ml-1 for (RAM) Ramipril, (VOR) Voriconazole, (SDC) Sildenafil Citrate, (ITM) Imatinib mesylate and (CFH) Ciprofloxacin hydrochloride respectively. The results of analyses were validated statistically. Statistical comparison of the results with the reference method shows excellent agreement and indicates no significant difference in accuracy and precision. The effect of excipients has also been studied and found to have no effect. These methods have been validated in terms of guidelines of ICH.Conclusion: The proposed methods have good selectivity and a correct sensibility; they rely on the use of simple and cheap chemicals, but provide similar sensitivity to that obtained with the HPLC; sophisticated and more expensive technique.Â

Inter-device reliability of swept source and spectral domain optical coherence tomography and retinal layer differences in schizophrenia

INTRODUCTION: Optical coherence tomography (OCT) is used to study retinal structure in schizophrenia. Changes in retinal structure, especially the retinal nerve fiber layer (RNFL) have been correlated with psychotic disorders. Along with a decrease in macular outer nuclear layer (ONL) thickness and an increase in macular outer plexiform layer (OPL). However, measurement variability is a concern for inner retinal layers since there are various generations of OCT devices resulting in differing measurements. We investigated the inter- and intra-device agreement of macular thickness between spectral domain (SD-OCT) and swept source-OCT (SS-OCT), and compared macula and peripapillary group differences in schizophrenia using SS-OCT for inner retinal layers. Additionally, we expanded on our previous work and investigated whether baseline outer retinal layer data for macular ONL and OPL thickness predicted clinical and cognitive changes in individuals with schizophrenia. METHODS: For the inter- and intra-scanner study, macular OCT thickness was obtained for schizophrenia (SZ, n=30) and healthy controls (HC, n= 22) subjects using SD-OCT (Heidelberg Spectralis) and SS-OCT (DRI Topcon Triton). Peripapillary thickness was obtained using SS-OCT. RNFL, ganglion cell-inner plexiform complex (GCL+), RNFL+ GCL+ (GCL++), and macular thickness were collected. For the longitudinal study, 7 participants diagnosed with either schizophrenia or schizoaffective baseline OCT measurements and clinical measures were obtained for all 7 participants from study 1, along with 6 months follow up clinical measures. OCT measurements for the macular OPL and ONL were gathered using the Heidelberg Spectralis Clinical and cognitive data was gathered. All statistical analyses were performed using R software. RESULTS: There was excellent inter-scanner agreement for GCL+ and GCL++ with Interclass correlation coefficient (ICC) values between r =0.92-0.99. Good to excellent intra-scanner agreement was present except for macular RNFL in the SS-OCT device. No significant peripapillary group differences were identified. Poorer (Global Assessment of Functioning) GAF scores were correlated with thinner macular layers. Greater mania symptoms were associated with smaller peripapillary GCL+ thickness (r=-0.43, p=0.03). Poor overall cognition was associated with smaller peripapillary retinal thickness (r=0.36, p=0.02). For the longitudinal study, an increase in baseline OPL thickness was correlated with worse positive symptoms according to the Positive and Negative Symptom Severity(PANSS) at the 6 month follow up (r=0.77, p=0.04) with a trend level effect for PANSS total scores (r=0.71, p=0.08). There was no significant correlation between the change in clinical or cognitive outcomes for 6 months and baseline OPL and ONL thickness. CONCLUSION: While there is RNFL variability, GCL+ and GCL++ are comparable between scanners SD-OCT and SS-OCT. Given that RNFL thinning is strongly implicated in psychotic disorders, the use of OCT scanners should not be interchanged due to increased RNFL measurement variability. Additionally, though further research is needed on investigating changes in clinical outcomes with changes in OCT measurements, OPL thickness might be a predictor of long-term clinical outcomes or changes in brain pathology for individuals with schizophrenia

Oil enclave economy and sexual liaisons in Nigeria's Niger Delta region

This thesis examines the intersection of oil enclave economy and the phenomenon of sexual liaisons in Nigeria’s Niger Delta region. The particular focus of this thesis is on the extent to which oil enclavity contributes to the emergence of sexual liaisons between local women and expatriate oil workers. Despite the fact that the Nigerian oil industry has been subjected to considerable scholarly debate for over five decades, this aspect of the social dimension of oil has not received adequate scholarly attention. Gender-specific discourse has tended to focus more on women protest. Other aspects, such as gender-specific violence that women in the region have had to live with, are either ignored or poorly articulated. Picketing of oil platforms by protesting women is celebrated as signs that women are active in the struggle against oil Transnational Companies (TNCs). While women protest is a significant struggle against oil TNCs, it has the potential of blurring our intellectual focus on the specific challenges confronting women in the Niger Delta. This study shows that since the inauguration of the Willink Commission in 1957, national palliatives meant to alleviate poverty in the Niger Delta region have not been gender sensitive. A review of the 1957 Willink Commission and others that came after it shows that the Nigerian state is yet to address the peculiar problems that the oil industry has brought to the women folk in the region. The paradox is that while oil provides enormous wealth and means of patronage to the Nigerian state elite, the oil TNCs, and better paid expatriate oil workers, a large section of the local Oil Bearing Communities (OBCs), especially women and unemployed youth, are not only dispossessed but survive in an environment characterised by anxiety and misery. With limited survival alternatives, youths resort to violent protest including oil thefts and bunkering. Local women are also immersed in this debacle because some of them resort to sexual liaisons with economically empowered expatriate oil workers as an alternative means of survival. This study therefore shifts the focus to women by exploring the extent to which sexual liaison reflects the contradictions in the enclave oil economy. The study employed an enclave economy conceptual framework to demonstrate that oil extractive activities compromise and distort the local economies of OBCs. This situation compels local women to seek for alternative means of survival by entering into sexual liaisons with more financially privileged expatriate oil workers. The study reviewed relevant secondary documentary sources of data. Further, it employed primary data collection techniques which include in-depth interviews/life histories, ethnographic observations, focus group discussions, and visual sociology. Besides obtaining the social profile and challenges facing the women involved in sexual liaisons with expatriate oil workers, the study provides an outline of participants’ narratives on the different social and economic dimensions of the intersection of oil enclave economy and sexual liaisons. The study found that some of the women involved in sexual liaisons with expatriate oil workers have been abandoned with ‘fatherless’ children. Some of them have also been rejected by their immediate family members and, in some cases, by their community. The study also found that the phenomenon of sexual liaisons and the incidents of abandoned ‘fatherless’ children that result from the practice, has over the years been played out through local resentment against oil TNCs and their expatriate employees. This finding helps to fill the gap in narratives and to make sense of the civic revolt and deepening instability in the Niger Delta region

Impacto da temperatura da superfície do mar na simulação da Zona de Convergência do Atlântico Sul

Durante o verão austral, diversas regiões do Brasil são afetadas por precipitação intensa, geralmente associada à Zona de Convergência do Atlântico Sul (ZCAS). O objetivo geral deste trabalho foi investigar a influência da resolução espacial e temporal dos dados de temperatura da superfície do mar (TSM) na simulação da precipitação associada à ZCAS. Foram realizadas simulações com o modelo BRAMS (Brazilian developments on the Regional Atmospheric Modeling System) para dois eventos de ZCAS, ocorridos em 1998 (El Niño) e 1999 (La Niña). A quantidade de precipitação acumulada na parte oceânica da ZCAS foi maior nos experimentos com TSM mais quente. Índices estatísticos foram utilizados para verificação do desempenho do modelo na simulação de precipitação nas regiões que compõem a ZCAS (oceânica, costeira e amazônica), com diferentes dados de TSM. A resolução espaço-temporal dos dados de TSM influencia de forma pouco significativa na representação da ZCAS pelo modelo BRAMS. O modelo é mais eficiente em identificar a ocorrência/não ocorrência de chuva do que em localizar núcleos mais intensos e seu desempenho foi superior (inferior) na região amazônica (oceânica) da ZCAS.FAPESP - Processo n. 2007/57101-2CNPqCAPES - PROE

High performance liquid chromatography mass spectrometric method for the simultaneous quantification of pravastatin and aspirin in human plasma: Pharmacokinetic application

AbstractA rapid and sensitive liquid chromatography–tandem mass spectrometric (LC–MS/MS) assay method has been developed and fully validated for the simultaneous quantification of pravastatin and aspirin in human plasma. Furosemide was used as an internal standard. Analytes and the internal standard were extracted from human plasma by liquid–liquid extraction technique using methyl tertiary butyl ether. The reconstituted samples were chromatographed on a Zorbax SB-C18 column by using a mixture of 5mM ammonium acetate buffer and acetonitrile (20:80, v/v) as the mobile phase at a flow rate of 0.8mL/min. The calibration curve obtained was linear (r≥0.99) over the concentration range of 0.50–600.29ng/mL for pravastatin and 20.07–2012.00ng/mL for aspirin. Method validation was performed as per FDA guidelines and the results met the acceptance criteria. A run time of 2.0min for each sample made it possible to analyze more than 400 human plasma samples per day. The proposed method was found to be applicable to clinical studies

Simulation toolkit for energy scavenging inertial micro power generators

Published versio

Design of Interactive Health Promotion Portal Prototype at House of Health Promotion TeFa

TeFa House of Health Promotion at Polije is a Teaching Factory that is currently initiated by the Health Department's Health Promotion study program. This TeFa serves as a platform for health communication, information, and education, as well as a space for research and the dissemination of research findings by faculty and students. Based on the conducted situation analysis, TeFa Health Promotion House currently lacks integration of communication, information, and education media into health promotion activities. This deficiency leads to suboptimal management of health media content. The aim of this research is to create a web portal design for this problem. The method used to develop this portal design is the User-Centered Design method. The results of testing and design analysis conclude that the portal design developed aligns with user expectations. The main features include Articles, Consultations, Videos, Audio, and Polls. For further research, the design can be expanded into an applicatio