Artificial Neural Network and Wavelet Features Extraction Applications in Nitrate and Sulphate Water Contamination Estimation

This work expounds the review of non-destructive evaluation using near-field sensors and its application in environmental monitoring. Star array configuration of planar electromagnetic sensor is explained in this work for nitrate and sulphate detection in water. The experimental results show that the star array planar electromagnetic sensor was able to detect nitrate and sulphate at different concentrations. Artificial Neural Networks (ANN) is used to classify different levels of nitrate and sulphate contaminations in water sources. The star array planar electromagnetic sensors were subjected to different water samples contaminated by nitrate and sulphate. Classification using Wavelet Transform (WT) was applied to extract the output signals features. These features were fed to ANN consequently, for the classification of different levels of nitrate and sulphate concentration in water. The model is capable of distinguishing the concentration level in the presence of other types of contamination with a root mean square error (RMSE) of 0.0132 or 98.68% accuracy

Capacitive sensors for measuring complex permittivity of planar and cylindrical structures

With the increasing use of low-conductivity structural and functional materials, there has been a greater need for the efficient and reliable nondestructive evaluation (NDE) of these materials. One approach to evaluate low-conductivity structural and functional materials is to characterize the material dielectric property. In this thesis, capacitive sensors are developed for measuring complex permittivity of planar and cylindrical materials. For each sensor configuration, models are developed to allow for inverse determination of material permittivity from measured capacitance, therefore realizing quantitative characterization of material dielectric properties. In the first half of the thesis, coplanar concentric capacitive sensors are developed to meet the need of detecting water or excessive inhomogeneities caused by repairs in aircraft radome structures. Another important motivation is the absolute dielectric property characterization of laminar structures. Three coplanar sensor configurations are designed: the simple two-electrode concentric configuration, the interdigital spiral and the interdigital concentric configurations. Corresponding numerical models are developed to predict the sensor capacitance for given test-piece structures. The validity of the models is verified by comparing numerical predictions and measurement results. The advantage and disadvantage of each sensor configuration is discussed. For the two-electrode concentric configuration, a prototype handheld probe is also fabricated, and has detected successfully 1 cc of low contrast liquid in a simulated radome structure. Curved patch capacitive sensors, presented in the second half of the thesis, are developed with the motivation of accurate and convenient permittivity measurement of cylindrical structures. It is demonstrated that the permittivity of homogeneous dielectric rods is inferred easily from measured sensor capacitance, based on analytical and numerical models developed here. Another practical application of the curved patch capacitive sensors is the quantitative evaluation of aircraft wiring insulation condition. In this work, wires are modeled as cylindrical dielectrics with a conductive core. A numerical relationship between the complex permittivity of the insulation and the sensor capacitance and dissipation factor is established. A prototype probe, developed based on this model, has distinguished successfully degraded wires from the control ones. The feasibility of utilizing the presented capacitive approach for quantitative evaluation of aircraft wiring insulation condition is demonstrated. Although the development of the capacitive sensors in this thesis is motivated by aerospace engineering related applications, results presented in this work have the potential to be applied to other engineering fields. Potential sensor applications and recommended future research are suggested at the end of the thesis

Impact of remittances on poverty reduction

Дознаке из иностранства представљају део дохотка који емигранти шаљу породици, рођацима, пријатељима у матичној земљи. Њихова величина непосредно је повезана са облицима и структуром миграционих кретања. Раст заступљености привремених и циркуларних миграција радника насупрот трајним миграцијама доприноси повећању прилива дознака. Упоредо са повећањем обима дознака расте и њихов макроекономски и микроекономски значај. За већину земаља у развоју са обимним емиграционим токовима, дознаке из иностранства представљају значајан и релативно стабилан извор спољног финансирања привреде који обезбеђује одржавање платнобилансне равнотеже. У односу на токове страних директних инвестиција и портфолио инвестиција дознаке показују нижу волатилност, односно знатно мање реагују на макроекономске шокове. Цикличан карактер дознака у односу на кретање БДП-а земље пријема одређен је мотивима слања дознака. У земљама ниског дохотка, у којима преовлађују алтруистички мотиви слања, дознаке показују контрациклични карактер, док се процикличност дознака у односу на БДП земље пријема везује за изражено присуство инвестиционих мотива. За домаћинства примаоце, дознаке представљају значајан извор додатног дохотка који омогућава већу потрошњу, виши животни стандард, обезбеђење образовања и здравствених услуга за чланове, што је резултат присуства алтруистичких мотива емиграната. Склоност слању дознака одређена је бројним социо-демографским карактеристикама емиграната, као и степеном њихове друштвене и емотивне повезаности са емиграционом земљом. Већа вероватноћа слања дознака присутна је код емиграната чији супружник, деца или родитељи живе у матичној земљи, као и код оних који планирају повратак, инвестирање и/или имају интензивне друштвене контакте са особама у матичној земљи. Подстицање привремених и циркуларних миграција доприноси расту прилива дознака, док програми сједињавања породица имиграната и ii добијања држављанства, као и дужи период рада у иностранству воде асимилацији и већој интегрисаности у друштвени живот имиграционе земље, те слабе мотиве слања дознака.Remittances represent a part of an income the emigrants send to their families, relatives, friends living in the home country. Their size is directly connected with forms and structure of migrations. The growth of temporary and circular labour migration flows, as opposed to the permanent migration, contributes to the remittance inflows increasing. Along with the remittances volume increasing, their macroeconomic and microeconomic importance grows too. For the most developing countries with large emigration flows, remittances represent a substantial and relatively stable source of external financing of economy, providing in this way the balance of payments maintenance. Comparing with the foreign direct investments and portfolio investments, remittances show lower volatility i.e. they react significantly less to macroeconomic shocks. Remittance cyclical properties, in relation to the GDP of the receiving country, have been determined with the motives of sending remittances. In the low income countries where prevail altruistic motives of sending, remittances are countercyclical, while procyclicality of remittances, in relation to the GDP of receiving countries, has been connected with prevailing presence of investment motives. For the remittance receiving households, remittances represent a substantial source of additional income providing a higher consumption, higher standard of living, education and health care services for the members – showing the emigrants altruistic motives. Their tendency to send remittances has been determined with a number of socio-demographic characteristics of the emigrants, as well as with a degree of their social and emotional connection with emigration country. The emigrants whose spouse, children or parents live in the home country as well as those who plan to return, to invest and/or have more intensive social contacts with the persons in their home country, have a higher likelihood for sending the remittances. The incitement of temporary and circular migrations contributes to the remittance inflows growth while programs of family reunification and acquisition of legal permanent resident status as v well as a longer period of working abroad lead to assimilation and higher integration in the society of immigration country and weak motives for sending remittances

Monitoring of Biodiesel Transesterification Process Using Impedance Measurement

Alternative diesel fuels have been the subject of extensive investigation. Fatty acid methyl ester (FAME) based Biodiesel manufactured from vegetable oils or animal fats is an excellent candidate to replace common diesel fuel being renewable, non-toxic and often giving rise to reduced exhaust gas emissions. The transesterification process has been commonly and widely used to produce biodiesel from vegetable oil or animal fat. Vegetable oils or animal fats generally have viscosities higher than standard diesel oil. This means that it is necessary to reduce the viscosity by means of reacting vegetable oil with alcohol in the presence of a suitable catalyst. The target product for this reaction is methyl ester, with glycerol and potentially soap produced as by products with the process of transesterification. Methylester (Biodiesel) is produced by converting triglycerides to alkylesters. A batch transesterification process has two significant mechanisms, and exhibits a mass transfer controlled region that precedes a second order kinetically controlled region. In order to control the conversion process it is useful to employ process monitoring. In particular monitoring of the mass transfer processes that limits the initial reaction rates could prove to be beneficial in allowing for process optimization and control. This thesis proposes the use of a new method of biodiesel process monitoring using low frequency (15kHz) impedance sensing which is able to provide information regarding the progress of mass transfer and chemical reaction during biodiesel production. An interdigitated (ID) sensor has been used to monitoring the biodiesel process The ID sensor is of simple construction and consists of two sets of interleaved electrodes (fingers). The two sets of electrodes are separated by a gap and when an AC excitation voltage is applied across the interleaved electrodes an oscillating electric field is developed. The response of the fluid surrounding the sensor to the applied excitation was then used to determine progress of the chemical reaction by evaluating the real and complex impedance. A significant and unambiguous change in the components of impedance has been shown to occur during mixing (mass transfer) and transesterification. The impedance measurements gained during transesterification were then used for the development of a system model. A systematic approach was used to select mathematical models and system identification techniques were evaluated. The system identification investigation used real process measurement data in conjunction with the Matlab system identification toolbox

TEMPLATED SINGLE-CHAIN POLYMER-BASED ELECTROCHEMICAL SENSING

A target receptor is an essential component in developing selective biological and chemical sensors. Among various approaches in receptor implementation, templated polymers are synthetic biochemical receptors that mimic natural molecular recognition. They have the favorable arrangement of polymer structures to be steady in harsh conditions and can also be custom tailored to exhibit target affinity as well as interfacing with transducers. Effective templated polymer synthesis depends on the co-polymerization of functional monomers which will interact with the sensing molecule. This thesis proposes a rational design approach towards the integration of templated polymers with electrochemical sensing. The synthesized single-chain label-free flexible polymers with binding sites show selective affinity toward both electroactive and non-electroactive target molecule. This thesis proposes a novel approach in electrochemical templated polymer-based sensing platform. The developed platform shows binding-induced changes in the electron transfer kinetics at the templated polymer-attached electrode when the target molecule binds specifically to the receptor. In this work, a stimuli-responsive single-chain copolymer was developed for explicit analyte detection of 4-nitrophenol, a neurotoxin and environmental pollutant, and L-glutamate, a well-known neurochemical. The polymer backbone experiences a conformation change upon template binding and the electrochemical measurement can be used to characterize these changes. This new detection approach can be used for label-free sensing of various non-electroactive chemical species and can potentially lead to the development of a non-enzymatic electrochemical sensors

Novel approaches to the control of infectious diseases

As part of our ongoing efforts to find new drug leads against infectious diseases, several terrestrial and marine macro- and microorganisms were investigated. Several bioactive molecules, presented below, were isolated from these natural products. The mass-screening of dozens of marine Actinomycetes was completed and several Streptomyces with interesting biological activity profiles identified. A few examples are the Streptomyces code H747 and the Streptomyces code H668, a bacterium from which a new (5) and two known polyethers, the antimalarial agent K41-A (6) and its C-29 analog (7) were isolated. Five new six-membered ring cyclic peroxides: plakinastreloic acid A (8), methyl plakinastreloate A (9), the C-12 epimers of methyl 13, 14-epoxyplakinastreloate (10 & 11), and plakinastreloic acid B (12) were isolated from a marine sponge of the genus Plakinastrella. Compounds 8 and 9 exhibited antifungal activities against Candida albicans (IC50 = 6.5 µg/mL and 3.5 µg/mL, respectively), Aspergillus fumigatus (IC50 = 4.0 µg/mL and 9.0 µg/mL, respectively) and Cryptococcus neoformans (IC50 = 4.0 µg/mL and 9.0 µg/mL, respectively). A moderate antimalarial activity against CQ-resistant and CQ-sensitive strains of Plasmodium falciparum was observed, as well. It was also established that 8 possesses anti-HCV (Hepatitis C Virus) activity. Two other compounds were isolated from HCV active methanol extracts of Inga fagifiolia (twigs) and Diplostephium rhodendroides (leaves). These compounds were identified as 2,3,4,5,6-pentahydroxy-2-(hydroxymethyl)hexanamide (14), the amide of a known molecule and 4,5-dihydroxy-3-[(3,4,5-trihydroxy-6-methyltetrahydro-2H-pyran-2-yl)oxy] pentanoic acid (15). The bioassay-guided approach used for their isolation and structure elucidation is reported here. The potential of scCO2 to inactivate bacteria trapped in the gut of oysters was studied. It was established that exposing oysters to CO2 at 100 bar and 37 °C for 30 minutes and at 172 bar and 60 °C for 60 minutes induced 2-log and 3-log reductions in the APC loads, respectively. The decrease in the microbial load as a result of treatment with scCO2 was found to be significant (P = 0.002). A blind study allowing sensory analysis of treated vs. untreated oysters was also completed; no significant difference in the physical appearance, smell, or texture was recorded

Advances in Electronic-Nose Technologies Developed for Biomedical Applications

The research and development of new electronic-nose applications in the biomedical field has accelerated at a phenomenal rate over the past 25 years. Many innovative e-nose technologies have provided solutions and applications to a wide variety of complex biomedical and healthcare problems. The purposes of this review are to present a comprehensive analysis of past and recent biomedical research findings and developments of electronic-nose sensor technologies, and to identify current and future potential e-nose applications that will continue to advance the effectiveness and efficiency of biomedical treatments and healthcare services for many years. An abundance of electronic-nose applications has been developed for a variety of healthcare sectors including diagnostics, immunology, pathology, patient recovery, pharmacology, physical therapy, physiology, preventative medicine, remote healthcare, and wound and graft healing. Specific biomedical e-nose applications range from uses in biochemical testing, blood-compatibility evaluations, disease diagnoses, and drug delivery to monitoring of metabolic levels, organ dysfunctions, and patient conditions through telemedicine. This paper summarizes the major electronic-nose technologies developed for healthcare and biomedical applications since the late 1980s when electronic aroma detection technologies were first recognized to be potentially useful in providing effective solutions to problems in the healthcare industry

Biosensors for Diagnosis and Monitoring

Biosensor technologies have received a great amount of interest in recent decades, and this has especially been the case in recent years due to the health alert caused by the COVID-19 pandemic. The sensor platform market has grown in recent decades, and the COVID-19 outbreak has led to an increase in the demand for home diagnostics and point-of-care systems. With the evolution of biosensor technology towards portable platforms with a lower cost on-site analysis and a rapid selective and sensitive response, a larger market has opened up for this technology. The evolution of biosensor systems has the opportunity to change classic analysis towards real-time and in situ detection systems, with platforms such as point-of-care and wearables as well as implantable sensors to decentralize chemical and biological analysis, thus reducing industrial and medical costs. This book is dedicated to all the research related to biosensor technologies. Reviews, perspective articles, and research articles in different biosensing areas such as wearable sensors, point-of-care platforms, and pathogen detection for biomedical applications as well as environmental monitoring will introduce the reader to these relevant topics. This book is aimed at scientists and professionals working in the field of biosensors and also provides essential knowledge for students who want to enter the field