To see the other types of publications on this topic, follow the link: Chemical senses.
Dissertations / Theses on the topic 'Chemical senses'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Chemical senses.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Kelly, Lisa S. "Chemical communication during mate recognition in the harpacticoid copepod tigriopus japonicus." Diss., Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/25219.
Full text
2
So, Wai Kar. "Sex pheromone in caenorhabditis : defining its identity and its perception pathway /." View abstract or full-text, 2006. http://library.ust.hk/cgi/db/thesis.pl?AMCE%202006%20SO.
Full text
3
Chan, Chung Man. "Sex pheromone in caenorhabditis : its production and perception /." View abstract or full-text, 2007. http://library.ust.hk/cgi/db/thesis.pl?BIOL%202007%20CHANC.
Full text
4
Pisut, Daniel P. "The distance chemosensory behavior of the sea urchin Lytechinus variegatus." Connect to this title online, 2004. http://etd.gatech.edu/theses/available/etd-01052004-121047/.
Full textAbstract:
Thesis (M.S.)--Georgia Institute of Technology, 2004.Title from PDF t.p. (viewed on Oct. 28, 2006). Julia Kubanek, Committee Member; Mark Hay, Committee Member; Marc Weissburg, Committee Chair. Includes bibliographical references (p. 47-51).
5
Addagulla, Swapna. "Functional silane based co-polymers for biofuntionalization studies, chemical sensing and separations /." View online ; access limited to URI, 2009. http://0-digitalcommons.uri.edu.helin.uri.edu/dissertations/AAI3401132.
Full text
6
Bromley, Ryan F. "Art in the mouth : a critical evaluation of the chemical senses in contemporary art." Thesis, Oxford Brookes University, 2016. https://radar.brookes.ac.uk/radar/items/db2c7a2b-ceaa-4b47-bd4e-ef15380ca58f/1/.
Full textAbstract:
Can the experiences that we have when we eat and smell make a meaningful contribution to art? Often referred to as ‘the bodily senses’ or ‘the lower senses’, the chemical senses of taste, olfaction and chemesthesis have been determined as unsuitable for inclusion in art in classical philosophical literature. This research challenges that exclusion by exploring the classical judgements and asking if these senses have anything to contribute to contemporary art. If so, what are the contributions of these senses and their limitations? This is new research within art theory that draws upon multidisciplinary research findings within the fields of life sciences, cognitive studies, anthropology, sociology, philosophy, food studies and flavour and fragrance chemistry. The contributions of this research are: assertions derived from data and expert opinions from within these fields; curated events which provide examples and discourse for critical consideration; and the proposal of a new paradigm that is the result of the synthesises of the research findings. My research strategy began with a survey of related literature and industry practice within art. A series of interviews with leading scientists contributed a contemporary understanding of these senses in life sciences. Case studies were developed, with insights from cognitive sciences, which investigated the conceptual potential of contemporary gastronomy. Finally, discourse was introduced through curated events and artistic actions that made relevant assertions concerning the suitability of these senses in art. Art is an expression of human experiences which are mediated by all of our senses. The implication of this research is a fresh starting place for critical discourse concerning the inclusion of the chemical senses in art that is founded upon current scientific knowledge. Broader implications of this research include a paradigm that could be applied to a possible new field of study, Critical Studies in Contemporary Gastronomy.
7
Velamakanni, Aruna M. "Functional silane based polymers for sensing and separations /." View online ; access limited to URI, 2006. http://0-digitalcommons.uri.edu.helin.uri.edu/dissertations/AAI3248243.
Full text
8
Shabani, Shkelzen. "The Role of Chemical Senses in Predation, Risk Assessment, and Social Behavior of Spiny Lobsters." Digital Archive @ GSU, 2008. http://digitalarchive.gsu.edu/biology_diss/44.
Full textAbstract:
Chemical senses play a critical role in predator-prey and social interactions of many animals. Predators often evoke adaptive escape responses by prey, one of which is the release of chemicals that induce adaptive avoidance behaviors from both predators and conspecifics. I explore the use of chemicals in predator-prey and social interactions, using a crustacean model system, the spiny lobster. As predators, spiny lobsters are opportunistic, polyphagous feeders, and they rely heavily on their chemical senses during feeding. Some of their potential prey deter attacks through chemical defenses that act through the spiny lobsters’ chemical senses. An example of this is sea hares, Aplysia californica, which secrete an ink when vigorously attacked by sympatric spiny lobsters, Panulirus interruptus. I show that that this ink defends sea hares from spiny lobsters through several mechanisms that include phagomimicry, sensory disruption, and deterrence, and that the ink’s efficacy is enhanced by its naturally high acidity. As prey, spiny lobsters rely heavily on their chemical senses to assess risk from predators. One way to assess risk of predation is through ‘alarm cues’, which are injury-related chemicals. I show that injured Caribbean spiny lobsters, Panulirus argus, release alarm cues in their hemolymph, and that nearby conspecifics detect these cues using olfaction. Hemolymph from conspecifics induces primarily alarm behavior in the form of retreat, sheltering, and suppression of appetitive responses. In contrast, hemolymph from heterospecifics, depending on phylogenetic relatedness, induces either mixed alarm and appetitive behaviors or primarily appetitive behaviors. Spiny lobsters also use chemical cues to assess risk during social interactions with conspecific. I show that spiny lobsters use urine-borne chemical signals and agonistic behaviors to communicate social status and that these chemical signals are detected exclusively by the olfactory pathway. Dominant animals increase urine release during social interactions, whereas subordinates do not. Experimental prevention of urine release during interactions causes an increase in agonism, but this increase is abolished when urine of dominants is reintroduced. My findings lay the foundation for neuroethological studies of risk-assessment systems mediated by intraspecific chemical cues.
9
Ma, Yun. "Photofunctional molecular materials for chemical sensing, bioimaging and electrochromic applications." HKBU Institutional Repository, 2015. https://repository.hkbu.edu.hk/etd_oa/206.
Full textAbstract:
This thesis is dedicated to developing novel photofunctional molecular materials for the applications in chemical sensing, bioimaging and electrochromic. To begin with, a brief introduction of photofunctional molecular materials and an overview of their applications in chemical sensing, bioimaging and electrochromic were presented in Chapter 1. In chapter 2, we have synthesized a series of water-soluble phosphorescent cationic iridium(III) solvato complexes (1-7) as multicolor cellular probes for imaging in living cells. All of these complexes can be dissolved in PBS. The emission of complexes can be tuned from green to red by changing the chemical structure of cyclomedtalating ligands. All complexes exhibit low cytotoxicity to living cells and exhibit cell membrane permeability and specific staining of cytoplasm. They enter the cells by the mechanism of energy-independent passive diffusion mechanisms. More importantly, complex 7 can act as a two-photon phosphorescent cellular probe, and fluorescence lifetime imaging microscopy is successfully applied for bioimaging in the presence of short-lived background fluorescence. We developed two excellent optical probes for CO2 detection in Chapter 3. The first one for the CO2 detection is a phosphorescent probe based on an iridium(III) complex with 2-phenylimidazo-[4,5-f][1,10]phenanthroline. After bubbling CO2 into the detection solution, the quenched phosphorescence by the addition of CH3COO can be recovered. Photobleaching experiment demonstrates that this phosphorescent CO2 probe shows higher photostability than some of the reported organic probes. More importantly, the time-resolved PL experiment demonstrates that this probe can be used to detect CO2 in the presence of strong background fluorescence, which improves the sensitivity and signal-to-noise ratio of the sensor in complicated media. The second one is a water-soluble fluorescent probe based on tetraphenylethene derivative. After bubbling CO2 into the detection solution, remarkable color change and fluorescence enhancement could be observed. The response of this probe to CO2 in aqueous solution is fast and the detection limit is about 2.4 × 106 M. To emphasize the practical application of this probe, a porous film was successfully fabricated by mixing the dye with sodium carboxymethyl cellulose in water, which can serve as an efficient CO2 gas sensor. More importantly, this probe exhibits low cytotoxicity towards live cells and has the ability to monitor the external CO2 concentration changes of living cells. Chapter 4 focused on the development of novel soft salt based phosphorescent probe. This type of probe consists of two oppositely charged ionic complexes with two distinguishable emission colors, which makes it a perfect candidate as a ratiometric probe. The emission color of 10 changes from blue to red with increasing pH value. 10 is cell-permeable and exhibits low cytotoxicity, and it has been successfully applied for ratiometric pH imaging with the use of confocal microscopy, demonstrating its great potential for intracellular environment monitoring. Furthermore, phosphorescence lifetime imaging experiments can detect intracellular pH variations by photoluminescence lifetime measurements, which allowed for eliminating background fluorescence and selecting long-lived phosphorescence images. Quantitative measurement of intracellular pH fluctuations caused by oxidative stress has been successfully carried out for 10 based on the pH-dependent calibration curve. A series of cationic Zn(II) complexes has been designed and synthesized in chapter 5. The photophysical properties of these Zn(II) complexes are affected by the counterions. By altering the counterions, the emission peak can be changed from 549 nm to 622 nm. Interestingly, the CIE coordinate and the emission colors can be simply tuned by adjusting the concentration of 11d in the polyether. Under an electric field of about 15 V applied onto the electrodes, the emission color of the solution of 11b-11d near the cathode changed its original emission color to sky blue. Based on this interesting electrochromic fluorescence of 11d, a quasi-solid information recording device has been successfully designed. Furthermore, data encryption has been realized by combining 1d with BODIPY, and information decoding processed has been accomplished, for the first time, by employing TPA excitation techniques, in which the large TPA cross section of 11d is differentiated from small TPA cross section of common organic dyes. Finally, Chapters 6 and 7 present the concluding remarksand the experimental details of the work described in Chapters 25
10
Visser, Runine (Runine Cecile). "Chemical communication : chemical characterization of volatile constituents of urine of the southern African cheetah, Acinonyx jubatus jubatus, using headspace sampling and GC-MS." Thesis, Stellenbosch : Stellenbosch University, 2002. http://hdl.handle.net/10019.1/52730.
Full textAbstract:
Thesis (MSc)--Stellenbosch University, 2002.ENGLISH ABSTRACT: The cheetah, Acinonyx jubatus, sometimes referred to as "the greyhound of the cats", is probably the most elegant member of the cat family. Formerly widespread in southern Africa it is now threatened with extinction. It occurs in open savanna and light woodland, but also hilly country on occasion. The cheetah is a predator that can reach speeds of more then 110 km/h in short bursts. With a mass of between only 40 to 60 kg, it is not very powerful and cannot defend itself very effectively against carnivores such as the lion and hyaena, for example. This might be the reason why, in order not to advertise its presence, the urine of this animal is practically odourless. In turn, this might explain why no research has so far been devoted to the urine of this animal. In contrast extensive work has been done on the chemical characterisation of the urine of many other carnivores, notably the lion. Extraction of the urine with dichloromethane gave too little material for GC-MS. SPME sampling of the urine itself gave insufficient sample enrichment. Better results were obtained when an SPME-type of headspace sampling, using a larger mass of polydimethylsiloxane, was employed although many of the constituents of the urine could still barely be detected. The compounds identified include a large number of ketones, aldehydes, cyclic and acyclic ethers, carboxylic acids, amides two sulphur compounds in barely detectable quantities, and elemental sulphur. Perhaps the most remarkable result of this thesis is that it was found that the urine of the cheetah, although it is a carnivore, does not contain several sulphur compounds in relatively high concentrations. However, it does contain elemental sulphur. Perhaps a mechanism exists by which the cheetah can convert strongly odorous sulphur containing compounds into the less strongly smelling sulphur.
AFRIKAANSE OPSOMMING: Die jagluiperd, Acinonyx jubatus, 'n roofdier wat tydens 'n jagtog vir kort tye snelhede van meer as 110 km/h kan bereik, is waarskynlik die elegantste lid van die katfamilie. Met sy vaartbelynde liggaam weeg die dier egter slegs tussen 40 en 60 kg kan hy homself nie doeltreffend teen groter roofdiere verdedig nie. Chemiese verbindings, sogenaamde feromone, wat onder andere in die uriene uitgeskei word, word dikwels deur diere gebruik vir gebiedsafbakening en om met ander lede van die spesie te kommunikeer. Die uriene van die jadluiperd is egter feitlik reukloos. Tot dusver is die chemiese samestelling van die uriene van die jagluiperd nog nie ondersoek nie. Ekstraksie van die uriene met dichlorometaan het te min materiaal vir gaschromatografies-massaspektrometriese analise opgelewer, maar bevredigende resultate is verkry deur van 'n verbeterde monsternemingsmetode gebruik te maak. 'n Groot aantal organiese verbindings en twee swawelbevattende verbindings in skaars waarneembare hoeveelhede is in die uriene geïdentifiseer. Daar is egter 'n aansienlike hoeveelheid van die element swawel is in die uriene gevind. Laasgenoemde ontdekking, is die mees verbasende resultaat van hierdie navorsing. Die uitskeiding van swawel in uriene is, sover bekend, eenmalig in die soogdierwêreld. Dit is moontlik dat die jagluiperd oor 'n meganisme beskik om swawelverbindings wat baie sterk ruik om te sit na swawel wat nie so sterk ruik nie. Hierdie meganisme sal die dier se kanse op oorlewing verbeter deur van die swawelbevattende verbindings in sy dieet ontslae te raak sonder om sy teenwoordigheid in die omgewing te adverteer.
11
Dickman, Brian D. "Chemical and hydromechanical cue structure in the context of turbulent odor plume tracking." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/26501.
Full textAbstract:
Thesis (Ph.D)--Civil and Environmental Engineering, Georgia Institute of Technology, 2009.Committee Member: Roberts, Philip; Committee Member: Sturm, Terry; Committee Member: weissburg, marc; Committee Member: yoda, minami. Part of the SMARTech Electronic Thesis and Dissertation Collection.
12
Cohen, Staci Padove. "Functional identification and initial characterization of a fish co-receptor involved in aversive signaling." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/29677.
Full textAbstract:
Thesis (Ph.D)--Biology, Georgia Institute of Technology, 2009.Committee Chair: McCarty, Nael A.; Committee Co-Chair: Kubanek, Julia; Committee Member: Derby, Charles; Committee Member: Goodisman, Michael; Committee Member: Pardue, Machelle; Committee Member: Weissburg, Marc. Part of the SMARTech Electronic Thesis and Dissertation Collection.
13
Slade, Desmond. "Olfactory communicatiaon : chemical characterization of the interdigital secretion of the black wildebeest, Connochaetes gnou." Thesis, Stellenbosch : Stellenbosch University, 2000. http://hdl.handle.net/10019.1/51859.
Full textAbstract:
Thesis (PhD)--Stellenbosch University, 2000.ENGLISH ABSTRACT: The black wildebeest, Connochaetes gnou, is a terriorial animal and although it is not generally accepted, it is believed that it defines its territory by scent marking, using interdigital and preorbital secretions, faeces, and urine. The aim of this study was to characterize the chemical constituents of the interdigital secretion. Due to the complexity of the secretion, only one hundred and ten of the approximately 350 compounds could be determined with known techniques. Gas chromatography, low resolution GC-MS and retention-time comparison were the main analytical techniques used. Classes of compounds identified in the interdigital secretion include the following: • Hydrocarbons - Aliphatic (saturated and unsaturated) and aromatic • Alcohols - Aliphatic (saturated, unsaturated, cyclic and diols) • Phenols and Phenylalkanols • Aldehydes - Aliphatic (saturated and unsaturated) and aromatic • Ketones - Aliphatic (saturated, unsaturated, cyclic and diketones) and aromatic • Hydroxy ketones - Aliphatic and cyclic • Carboxylic acids - Aliphatic (saturated, unsaturated and cyclic) and aromatic • An anhydride • Esters - Methyl esters, ethyl and higher esters, unsaturated esters and aromatic esters • Lactams • A steroid Only small qualitative and quantitative differences were found between the male and female interdigital secretions.
AFRIKAANSE OPSOMMING: Die swartwildebees, Connochaetes gnou, is 'n territoriale dier en alhoewel dit nie algemeen aanvaar word nie, word vermoed dat hierdie bokke hul gebied afbaken met behulp van interdigitale en preorbitale afskeidings, en deur faeces en urine. Die doel van hierdie studie was om die chemiese samestelling van die interdigitale afskeiding te karakteriseer. As gevolg van die kompleksiteit van die afskeiding, kon slegs eenhonderd-en-tien van die ongeveer 350 verbindings met bekende bestaande tegnieke geïdentifiseer word. Gaschromatografie, lae resolusie GC-MS en retensietyd-vergelyking was die belangrikste analitiese tegnieke wat gebruik is. Klasse van verbindings wat bepaal is, sluit die volgende in: • Koolwaterstowwe - Alifaties (versadig en onversadig) en aromaties • Alkohole - Alifaties (versadig, onversadig, siklies en diole) • Fenole en Fenielalkanole • Aldehiede - Alifaties (versadig en onversadig) en aromaties • Ketone - Alifaties (versadig, onversadig, siklies en diketone) en aromaties • Hidroksiketone - Alifaties en siklies • Karboksielsure - Alifaties (versadig, onversadig en siklies) en aromaties • 'n Anhidried • Esters - Metiel esters, etiel en hoër esters, onversadigde esters en aromatiese esters • Laktame • 'n Steroïed Slegs klein kwalitatiewe en kwantitatiewe verskille is gevind tussen die bul en koei interdigitale afskeidings.
14
Tang, Wing-suen. "Design and synthesis of luminescent metal polypyridyl complexes of platinum(II), ruthenium(II) and osmium(II) for chemosensing and biological studies." Click to view the E-thesis via HKUTO, 2006. http://sunzi.lib.hku.hk/hkuto/record/B38767624.
Full text
15
Horner, Amy Jean. "Functional Roles of Crustacean Dual Antennular Chemosensory Pathways in Odor Mediated Behaviors." Digital Archive @ GSU, 2007. http://digitalarchive.gsu.edu/biology_diss/18.
Full textAbstract:
Odor signals mediate a variety of behaviors in animals across a diversity of taxa. Despite dramatic morphological differences between animals from different taxa, several important features of olfactory system organization and processing are similar across animals. Because of this similarity, a number of different organisms including mammals, insects, and decapod crustaceans serve as valuable model systems for understanding general principles of olfactory processing. As in other organisms, including both vertebrates and insects, the chemosensory system of decapod crustaceans is organized into multiple anatomically distinct neuronal pathways. The two main pathways (the aesthetasc/ olfactory lobe pathway and non-aesthetasc/ lateral antennular neuropil pathway) originate in different populations of antennular sensilla and project to different neuropils in the brain. The functional significance of this parallel organization is not well understood in crustaceans or in many other species. Although in some insect species the functions of parallel pathways are clearly delineated by the types of odors processed by each, functional differences between parallel pathways in other organisms are much less distinct. A critical step towards understanding the functional significance of the multiple chemosensory pathways is to identify the specific behaviors that are driven by each pathway. Using spiny lobsters and crayfish as model organisms, the importance of each pathway was examined in three different behavioral contexts: (1) orientation to a distant food odor, (2) shelter selection in response to conspecific chemical signals, and (3) determination of conspecific social status. In each study, selective ablations of specific populations of antennular sensilla were performed, and the behavior of ablated animals was compared to that of intact controls. Results show that either the aesthetasc or non-aesthetasc pathway is capable of driving orientation to food odors, suggesting functional redundancy between the pathways in this behavior. In contrast social odors are processed preferentially by the aesthetasc pathway rather than the non-aesthetasc pathway, suggesting a unique role for the aesthetasc pathway in this context. As in other organisms possessing multiple chemosensory pathways, the dual antennular pathways in crustaceans display both unique and overlapping functions depending on the chemicals examined, and the behavioral context in which the signal is presented.
16
Louw, Stefan. "Chemiese kommunikasie van die Suid-Afrikaanse gordelakkedisse." Thesis, Stellenbosch : Stellenbosch University, 2003. http://hdl.handle.net/10019.1/49754.
Full textAbstract:
Thesis (PhD)--Stellenbosch University, 2003.ENGLISH ABSTRACT: The sungazer, Cordylus giganteus, is an endangered lizard species belonging to the family Cordylidae. It has been speculated that the function of semiochemical communication is performed by two types of skin glands, the femoral glands and the generation glands, which are also found in this family of lizards. Other skin glands and also the cloacal glands are further possible sources of semiochemicals. The investigation of these potential sources of chemical messages in C. giganteus, served as a starting point towards a better understanding of the chemical communication of lizard species belonging to the family Cordylidae. In continuation of this study the femoral gland secretion of the Cape girdled lizard, C. cordylus, was also investigated. Gas chromatography, low resolution GC-MS, GC-HR-MS, MO-TMS derivatisation and retention time comparison were used as analytical techniques in the chemical characterization of the femoral and generation gland secretions of C. giganteus and the femoral gland secretion of C. cordylus. Some compounds were not identified because of their low concentration in the secretions and/or mass spectra could not be obtained for pure compounds because of co-elution with other compounds. Compounds identified in the femoral gland secretion include the following: Carboxylic acids - saturated and unsaturated Alcohols Ketones Aldehydes - saturated and unsaturated Esters - saturated and unsaturated Hydrocarbons - saturated and unsaturated Nitriles Amides - saturated and unsaturated y-Lactones Squalene u-Tocopherol Steroids Quantitative analysis of the femoral and generation gland secretions of a number of sungazers indicated distinct differences between the secretions of males and females (in the case of the femoral gland secretions), but no apparent trend could be found in the differences between the femoral and generation gland secretions of individual lizards of the same gender. Qualitative seasonal differences were however observed in the femoral gland secretions of all individuals of C giganteus.
AFRIKAANSE OPSOMMING: Die ouvolk, Cordylus giganteus, is 'n bedreigde akkedisspesie van die familie Cordilidae. Daar is gespekuleer dat twee soorte velkliere wat by hierdie familie akkedisse voorkom, naamlik die femorale- en generasiekliere, betrokke is by semiochemiese kommunikasie van hierdie diere. Ander velkliere, asook die kliere in die akkedisse se kloaka, is ook potensiele bronne van semiochemiese verbindings. Die bestudering van hierdie potensiele bronne van chemiese boodskappe by C. giganteus is as 'n beginpunt gebruik om die semiochemiese kommunikasie van die akkedisse van die familie Cordilidae beter te verstaan. Ter uitbreiding van hierdie studie is die femorale klierafskeiding van die Kaapse gordelakkedis, C. cordylus, ook ondersoek. Die femorale en generasieklierafskeidings van C. giganteus en die femorale klierafskeidings van C. cordylus is chemies gekarakteriseer deur van analitiese tegnieke, naamlik gaschromatografie, lae resolusie GC-MS, GC-HR-MS, MO- TMS derivatisering en retensietydvergelyking, gebruik te maak. Talle verbindings is nie geidentifiseer nie omdat hulle in 'n baie lae konsentrasie in die afskeidings voorkom, en/of saam met ander komponente elueer, wat veroorsaak dat daar nie massaspektra vir hierdie suiwer komponente verkry kon word nie. Verbindingstipes wat in die afskeidings voorkom, sluit die volgende in: Karboksielsure - versadig en onversadig Alkohole Ketone Aldehiede - versadig en onversadig Esters - versadig en onversadig Koolwaterstowwe - versadig en onversadig Nitriele Amiede - versadig en onversadig y-Laktone Skwaleen a-Tocopherol Steroiede Kwantitatiewe analises van die femorale en generasieklierafskeidings van verskeie ouvolk akkedisse het getoon dat daar duidelike kwantitatiewe verskille tussen die afskeidings van mannetjies en wyfies is (in die geval van die femorale klierafskeidings), maar dat daar geen duidelike patroon in die verskille tussen die femorale en generasieklierafskeidings van individuele akkedisse van dieselfde geslag is rue. Daar is kwalitatiewe seisoenale verskille tussen die femorale klierafskeidings van individue van C. giganteus gevind.
17
Long, Jeremy Dillon. "Plasticity of Consumer-prey Interactions in the Sea: Chemical Signaling, Consumer Learning, and Ecological Consequences." Diss., Available online, Georgia Institute of Technology, 2004:, 2004. http://etd.gatech.edu/theses/available/etd-11182004-164652/unrestricted/long%5Fjeremy%5Fd%5F200412%5Fphd.pdf.
Full textAbstract:
Thesis (Ph. D.)--Biology, Georgia Institute of Technology, 2005.Hay, Mark, Committee Chair ; Dusenbery, David, Committee Member ; Kubanek, Julia, Committee Member ; Paffenhofer, Gustav-Adolf, Committee Member ; Yen, Jeannette, Committee Member. Includes bibliographical references.
18
Tadesse, Tizeta. "Adult Neurogenesis in the Spiny Lobster, Panulirus Argus: Molecular, Cellular, and Physiological Changes of Olfactory Receptor Neurons." Digital Archive @ GSU, 2012. http://digitalarchive.gsu.edu/neurosci_diss/6.
Full textAbstract:
Adult neurogenesis of olfactory receptor neurons (ORNs) occurs in diverse organisms including in decapod crustaceans. This dissertation describes the molecular, cellular, and physiological changes that occur during adult neurogenesis of ORNs in the antennular lateral flagellum (LF) of the spiny lobster Panulirus argus. Examination of the role of splash (spiny lobster achaete scute homolog) in adult neurogenesis and regeneration using in situ hybridization showed splash was not closely associated with the formation of sensory neurons under normal physiological conditions. Damage to the LF, which induces regeneration, enhanced splash expression, suggesting an association between splash with regeneration and repair. This study suggests that splash plays multiple roles in the olfactory organ of adult spiny lobsters. Examination of extracellular and intracellular Ca2+ in mediating spontaneous and odor-induced responses of ORNs, using calcium imaging showed that odor-induced Ca2+ transient responses and spontaneous Ca2+ oscillations in ORN somata are primarily mediated by an influx of extracellular Ca2+ through Co2+ -sensitive Ca2+ channels, but that intracellular Ca2+stores also have some contribution. These responses are independent of TTX-sensitive Na+ channels, suggesting that these Ca2+ responses may reflect receptor potentials. Examination of changes in odor specificity, sensitivity, and temporal responses in adult-born ORNs showed an increase in the percentage of odorant-responsive ORNs as they age from newly-born cells to mature, and a decrease in odorant-responsive ORNs as they senesce. As adult-born ORNs age, there was a decrease in the percentage of ORNs that undergo spontaneous Ca2+ oscillations and an increase in the amplitude of oscillation. ORNs became more broadly tuned as they senesce, and their response profile, defined by the most effective odorant, changed. Odor sensitivity changed with age. This study demonstrated that the physiological response properties of adult-born ORNs changed with functional maturation. Taken together, this dissertation reveals molecular, cellular and physiological changes in adult born ORNs and elucidates mechanisms of adult neurogenesis.
19
Tang, Wing-suen, and 鄧詠璇. "Design and synthesis of luminescent metal polypyridyl complexes of platinum(II), ruthenium(II) and osmium(II) for chemosensing andbiological studies." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2006. http://hub.hku.hk/bib/B38767624.
Full text
20
Viviers, Marlize Z. "Die karakterisering van die reukmerkvloeistof van die Bengaalse tier, Panthera Tigris Tigris." Thesis, Stellenbosch : University of Stellenbosch, 2006. http://hdl.handle.net/10019.1/1576.
Full textAbstract:
Thesis (MSc (Botany and Zoology))--University of Stellenbosch, 2006.Although the Bengal tiger, Panthera tigris tigris, appears on the IUCN Red Data List for endangered animals, very little information is available in the literature on the components of this animal's marking fluid. Scent marking is the main form of communication in all cat species. In some species, including the Bengal tiger, the liquid used for spraying is not pure urine, but is mixed with scent gland secretions. The objective of this study was to characterise the volatile components in the marking fluid of the Bengal tiger to achieve a better understanding of the semiochemical communication of this animal. The marking fluid of the tiger was characterised through the use of analytical techniques, such as gaschromatography, low resolution gas chromatography - mass spectrometry and retention time comparison. Homologous series of alkanes, alcohols, aldehydes, methyl ketones, carboxylic acids, γ- and δ-lactones, amides and lactams, as well as esters and nitrogen containing compounds, were identified. Of these identified compounds the unbranched alkanes, saturated alcohols, aldehydes, branched methyl ketones, saturated carboxylic acids and γ- and δ- lactones are commonly found in mammalian secretions. Compounds that aren't as common in their secretions are the methyl ketones, branched carboxylic acids, dimethyl esters of dicarboxylic acids and amides. The marking fluid contains a phthalic acid ester. Phthalic acid esters are used in the polymer industry and are nowadays found almost everywhere in nature. It is known that these pollutants have endocrine disrupting properties. The heat, humidity and wet conditions that are characteristic of the Bengal tiger's natural habitat makes it necessary for the tiger to make use of a fixative to prolong the life of the semiochemical message. The compounds and the concentrations in which these compounds are present in the urine and the lipid fraction of the marking fluid of the tiger was determined and compared to assess the fixative role of the lipids. This study has provided evidence that the lipid material has a greater affinity for the volatile organic constituents of the marking fluid and that it can therefore extend the lifetime of a semiochemical message left by the tiger.
21
Ferrante, Peter A. "Chemical Orientation Strategies of the Crayfish, Orconectes virilis are Influenced by the Hydrodynamics of their Native Environment: An Example of Sensory Bias." Bowling Green, Ohio : Bowling Green State University, 2008. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=bgsu1213281400.
Full text
22
Vergoz, Vanina, and n/a. "Effects of queen mandibular pheromone on locomotor behaviour and learning in worker honey bees Apis mellifera." University of Otago. Department of Zoology, 2008. http://adt.otago.ac.nz./public/adt-NZDU20081121.161845.
Full textAbstract:
In a honey bee colony, the queen uses queen mandibular pheromone (QMP) to induce young worker bees to feed and groom her. Among its many behavioural and physiological effects, QMP reduces dopamine levels in the brains of young worker bees. Dopamine is a biogenic monoamine involved in numerous functions including motor control and aversive learning. This study investigates the effects of QMP on motor activities and aversive learning behaviour and the potential link between QMP and dopamine levels in the brain of young bees.
In young bees under the age of 15-days, QMP dramatically reduced locomotor activity and inhibited aversive learning behaviour. Interestingly in older bees these behaviours were not affected by pheromone. Treating young bees with the dopamine precursor, L-dopa (3.25 [mu]g/mI), partially rescued the levels of locomotor activity in QMP-treated bees, and reduced QMP�s effects on aversive learning. This suggests that blocking effects of QMP on both locomotor activity and aversive learning result at least in part from QMP-induced changes in brain dopamine levels.
Two components of the QMP blend, 4-hydroxy-3-methoxyphenylethanol (HVA) and methyl p-hydroxybenzoate (HOB) were examined more closely. Both HVA and HOB are structurally similar to dopamine. HVA was found to mimic the effects of the full QMP blend on aversive learning. Treating bees with HVA reduced aversive learning in young bees. In contrast, treatment with HOB did not affect learning ability. This strongly suggests that HVA is one of the key components that mediates the actions of QMP on aversive learning.
The final section of this thesis investigates why it might be advantageous to honey bee queens to block aversive learning and reduce locomotor activity in young worker bees. The study reveals age-related differences in behaviours that individual worker bees display towards QMP. Young bees reared with QMP or collected from a queenright hive showed attraction to QMP. Conversely, older bees displayed avoidance behaviour towards QMP. By blocking the establishment of aversive memories, young bees may be prevented from forming an association between QMP and any unpleasant side effects induced by this pheromone. This may confer significant benefit to the queen by increasing the likelihood of young workers remaining in her attendance.
23
Viviers, Marlize Zaretha. "Investigation into the semiochemical communication involved in neonatal offspring recognition in sheep." Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/3980.
Full textAbstract:
Thesis (PhD (Chemistry and Polymer Science))--University of Stellenbosch, 2010.Video 1: Twin-bearing Döhne Merino ewe butting only one of her lambs in typical rejection behavior. Rejection of one twin is not a common phenomenon. (Video by Dr Marlize Viviers)
Video 2: Twin-bearing ewe # 22 accepting alien lamb # 179. The alien lamb wears a jacket her other lamb has been wearing for the preceding 24 hours. The excessive sniffing at the jacket, bleating and looking around show that the ewe is not totally satisfied with the situation. (Video by Dr Marlize Viviers)
Video 3: Ewe # 22 rejecting alien lamb # 179 after removal of the jacket it has worn in the previous video. (Video by Dr Marlize Viviers)
ENGLISH ABSTRACT: Sheep husbandry substantially contributes to South Africa’s economy. Lamb mortality is regarded as a major constraint to sustainable sheep production, and an important factor in lamb survival is the strong ewe–lamb bonding. This is a well-known phenomenon in all sheep races and strong evidence exists that the selective ewe–lamb bond formation has a pheromonal basis, in that the ewe can distinguish her lamb by its unique, familiar smell. Sheep farmers and scientists have examined various methods of making alien lambs acceptable to foster ewes. The survival rate of offspring could be substantially increased if a reliable method could be devised to prevent ewes from rejecting their own lambs or if ewes could be induced to accept alien lambs. A better understanding of the semiochemicals involved in this communication between ewe and offspring could facilitate the development of a method by which ewes can be coaxed into adopting foster lambs. This would positively contribute to efficient sheep production in South Africa. The objective of this study was to characterise the volatile constituents present in the wool and the amniotic fluid collected from the Döhne Merino lambs to achieve a better understanding of the ewe–lamb semiochemical communication. The volatile organic constituents associated with the wool and amniotic fluid were characterised and a total of 133 volatile organic compounds were identified. Several compound classes are represented in these samples and the majority of these compounds have previously been identified in the excretions and secretions of numerous mammalian species. A number of different aspects of ewe–lamb kin recognition were investigated. First, the odour profiles of twin lambs were compared to those of other twins. The results of these analyses revealed that the wool volatiles of twin lambs are qualitatively as well as quantitatively practically identical, but different from those of other lambs in the flock. Second, the change in the odour profiles of lambs was studied over a seven-day period. It was found that the odour profiles of lambs are not fixed, and for as long as a ewe makes use of olfactory recognition as the main mode of identification of her lamb she has to continue learning the odour of her lamb. Third, the amniotic fluid was investigated as a possible source of maternal labels, i.e. as chemical codes consisting of mixtures of compounds in specific quantitative ratios that are imprinted on lambs by their mothers at birth. It was found that the amniotic fluids of first- and second-born lambs are qualitatively and quantitatively different. It is possible that the duration of the lambing birth process could contribute to this change in amniotic fluid composition. Fourth, the role of residual proteins in the dissemination of the semiochemicals involved in ewe– lamb communication was investigated and six proteins were identified as amniotic fluid and wool-associated proteins. Bioassays carried out during the lambing season of 2009 confirmed the role of the odour of the lamb in ewe-lamb recognition, but bioassays carried out with synthetic pheromone formulations gave inconclusive results.
AFRIKAANSE OPSOMMING: Skaapboerdery lewer aansienlike bydrae tot die ekonomie van Suid Afrika, maar lamsterftes is een van die kwellende probleme waarmee kleinveeboere te kampe het. Die eksklusiewe band wat binne die eerste paar uur na 'n lam se geboorte tussen die ooi en haar lam ontwikkel, is die hooffaktor waarvan lammers se oorlewing afhang. Hierdie sterk binding tussen lam en ooi is 'n bekende verskynsel in alle skaap-rasse en dit is bekend dat 'n feromoon wat deur die lam vrygestel word, dit vir die ooi moontlik maak om haar lam aan sy unieke reuk uit te ken. Lamsterftes sou aansienlik verminder kon word as hierdie feromoon geïdentifiseer en gebruik kan word om ooie te verhoed om hulle eie lammers te verwerp en om die aanvaarding van vreemde lammers deur ooie moontlik te maak. Die doel van hierdie studie was die chemiese karakterisering van die vlugtige organiese verbindings aanwesig in die amniotiese vloeistof en wol van Döhne Merino lammers ten einde 'n beter begrip van die semiochemiese kommunikasie tussen ooie en lammers te verkry. In die amniotiese vloeistof is 70 vlugtige organiese verbindings geïdentifiseer. Dieselfde verbindings asook 'n verdere 63 verbindings is in lammerwol geïdentifiseer. Die meerderheid van hierdie verbindings is reeds voorheen in verskeie soogdierafskeidings gevind. Die studie het verskeie interessante aspekte van hierdie semiochemiese kommunikasie aan die lig gebring. Eerstens is daar gevind dat die samestelling van die vlugtige organiese materiaal in die wol van tweelinglammers, oftewel hul reukprofiele, feitlik identies is. Verder verskil die reukprofiele van 'n tweeling van dié van ander tweelinge en enkelinge in die trop. Tweedens is gevind dat die reukprofiel van 'n lam nie by geboorte vasgelê word en so behoue bly nie, maar dat dit geleidelik verander oor ten minste die periode van sewe dae waaroor hierdie verskynsel bestudeer is. Dit noodsaak die ooi om haar geheue met betrekking tot die lam se reuk voortdurend te verfris gedurende die tydperk wat sy hoofsaaklik van haar reuksin gebruik maak om haar lam te herken. Derdens is die amniotiese vloeistof ondersoek as moontlike bron van ‘n sogenaamde moedermerk, waardeur chemiese mengsel van verbindings wat in ‘n spesifieke kwantitatiewe samestelling by geboorte deur die ooi op haar lam agter gelaat word. Ten opsigte van kwalitatiewe en kwantitatiewe samestelling, verskil die vlugtige organiese fraksie van die amniotiese vloeistof van die tweelinglam wat eerste gebore word van die amniotiese vloeistof van die lam wat tweede gebore word. Dit is onwaarskynlik dat amniotiese vloeistowwe wat ten opsigte van hul vlugtige organiese fraksies van mekaar verskil, nagenoeg identiese moedermerke op tweeling lammers sou kon laat. Vierdens is vasgestel dat spore van ses proteïene uit die amniotiese vloeistof op die wol van lammers agtergelaat word. Daar kon ongelukkig nie vasgestel word of hierdie proteïene 'n rol in die vrystelling van semiochemiese inligting speel nie. Gedragstoetse wat tydens die lamseisoen van 2009 uitgevoer is, het bevestig dat die lam se reukprofiel deurslaggewende rol in ooi-lam herkenning speel, maar gedragstoetse wat met sintetiese feromoonmengsels uitgevoer is, het onbesliste resultate opgelewer.
24
Smee, Delbert Lee. "The Ecology of Yikes! Environmental Forces Alter Prey Perception of Predators." Diss., Connect to this title online, 2006. http://etd.gatech.edu/theses/available/etd-05082006-213823/.
Full textAbstract:
Thesis (Ph. D.)--Georgia Institute of Technology, 2006.Title from PDF t.p. (viewed on Oct. 28, 2006). Marc Weissburg, Committee Chair ; Mark Hay, Committee Member ; Lin Jiang, Committee Member ; David Dusenbery, Committee Member ; Don Webster, Committee Member. Includes bibliographical references (p. 115-122).
25
Allen, Caroline. "The artificially scented ape : investigating the role of fragrances and body odours in human interactions." Thesis, University of Stirling, 2015. http://hdl.handle.net/1893/22599.
Full textAbstract:
It was long believed that humans were unable to utilise the odours of conspecifics to co-ordinate social interactions in ways in which other species appear to be capable. However, a surge in interest in human social olfaction has recently challenged this view. The numerous studies conducted in this area have found that multiple state and trait related cues can be detected in body odour. Furthermore, many studies indicate that women are often more sensitive to these cues, and that sensitivity can be associated with fertility, findings that are consistent with sex differences in reproductive effort and benefits of choosiness in mate-searching. Since previous studies in this area have usually addressed the potential for humans to use olfactory communication in a comparable manner to other mammals, they typically involve collection and assessment of ‘natural’ odour. That is, they explicitly exclude the possibility of ‘contamination’ of odour samples by artificial fragrances. However, humans have used artificial fragrances for millennia, across many different cultures. This raises the question of whether widespread fragrance use may affect or disrupt the detection of this information in modern humans. The first aim of this thesis was to address this question by investigating how fragrance use may mediate the detection of olfactory information in humans. As well as providing further evidence for sex differences in the assessment of olfactory cues, and for the role of olfaction in real world partner choice, the findings herein suggest that fragrance may act differently on different information being assessed, potentially masking accurate assessment of certain traits (such as masculinity), while fragrance choice and preferences may be important in complementing other olfactory information (such as the general distinguishability of an individuals’ odour profile). A second aim of the thesis was to develop a scale in order to more accurately describe the varying perceptual qualities of human body odour – in other words to map human body odours. This work was conducted alongside perfumers in order to benefit from their expertise in olfactory perception and semantic labelling of odours. The development of such a scale could enable improved understanding of the perceptual qualities of human odour, making it possible to link specific perceptual qualities to specific cues (e.g. symmetry, masculinity, sex) or to manipulate odours based on perceptual qualities in experimental settings, and has direct practical implications for fragrance designers and for improving the ability of individuals to choose fragrance products that suit their odour profile. The second section of the thesis focuses on the effects of odours on the individual wearer as well as on perceivers in the environment. One study is presented which investigates the role of malodour reduction compared to the addition of fragrances in perceptions of confidence and attractiveness, finding that both the reduction of malodour and the addition of fragrance appear to be important for confidence as rated by others in the environment. The final study presented in the thesis examines a hitherto un-investigated role of olfaction during human pregnancy. The rationale for the study is based on evidence suggesting that in certain non-human species, which also show bi-parental care of offspring, there may be a role for chemical, or odour based, communication which underpins behavioural and endocrinological changes related to infant care behaviours in males. The study found little evidence to support the presence of analogous olfactory signalling during human pregnancy, though the findings are discussed in light of methodological changes which, if made in future studies, may result in different outcomes. The thesis concludes with a discussion of the importance of continuing to investigate various forms of olfactory communication, as well as improving our understanding of odours through the mapping of their perceptual qualities, and finally further examining the ways in which various fragranced products, which are widely used in society, may affect all of this. Future directions for this area of research are discussed. This line of investigation will, I argue, enable us to finally establish the true role of olfaction in contemporary social environments.
26
Cánovas, Martínez Rocío. "Tailor-made chemical sensing platforms for decentralized healthcare and wellbeing." Doctoral thesis, Universitat Rovira i Virgili, 2018. http://hdl.handle.net/10803/462914.
Full textAbstract:
Aquesta tesis fa referència a la necessitat social de la implementació de sensors electroquímics en la nostra vida quotidiana a diferents nivells. Des d’un enfocament sanitari, l’ús i l’aplicació real de plataformes fàcils d’utilitzar pel propi pacient facilitarien la presa de decisions gràcies a la obtenció d’informació rellevant i monitoratge d’una malaltia. Així mateix, l’ús d’aquestes eines de manera individual, en centres de salut o inclús hospitals, ajudarien a disminuir el cost que la sanitat ha d’afrontar diàriament. Des d’un enfocament diferent, aquest tipus de sensors poden oferir també altres tipus de aplicacions, poden ser usats amb finalitats mediambientals o de seguretat. La fabricació de sensors electroquímics (amperomètrics i potenciomètrics) integrats i impresos en diferents substrats fàcils de manipular, de baix cost i robustos (com tèxtils, globus o paper) ha estat aconseguida durant aquesta tesis. L’estudi del seu rendiment analític sota la influencia de diferents situacions d’estres i en diferents fluids biològics (detectant ions en suor o glucosa en sèrum i sang) també ha estat realitzat amb èxit. Aquestes aportacions tecnològiques van dirigides a superar els reptes que la societat d’avui en dia necessita solucionar: com pot ser la sostenibilitat del sistema sanitari en una població cada vegada mes envellida; el manteniment d’una seguretat i un estat del benestar; i el control mediambiental. Aquesta tesis suposa un avenç en aquest sentit i mostra diferents solucions científiques i eines útils per aquests reptes que la societat necessita afrontar.Esta tesis hace referencia a la necesidad social de la implantación de sensores electroquímicos en nuestra vida diaria a distintos niveles. Desde un enfoque sanitario, el uso y la aplicación real de plataformas fáciles de usar mediante el propio paciente facilitarían la toma de decisiones gracias a la obtención de información relevante y monitoreo de una enfermedad. Así mismo, el uso de estas herramientas de manera individual, en centros de salud o incluso hospitales disminuiría el costo que la sanidad debe afrontar diariamente. Desde un enfoque diferente, este tipo de sensores pueden ofrecer también otro tipo de usos, pudiendo ser aplicados para fines medioambientales o de seguridad. La fabricación de sensores electroquímicos (amperométricos y potenciométricos) integrados e impresos en diferentes sustratos fáciles de manipular, de bajo costo y robustos (como textiles, globos o papel) ha sido lograda durante esta tesis. El estudio de su rendimiento analítico bajo diferentes situaciones de estrés y en diferentes fluidos biológicos (detectando iones en sudor o glucosa en suero y sangre) también ha sido realizado de manera exitosa. Estas aportaciones tecnológicas van dirigidas a superar los retos que la sociedad de hoy en día necesita solucionar: como puede ser la sostenibilidad del sistema sanitario en una población cada vez más envejecida; el mantenimiento de una seguridad y un bienestar general; y el control medioambiental. Esta tesis supone un avance en este sentido y muestra diferentes soluciones científicas y herramientas útiles para estos retos que la sociedad necesita afrontar.
This thesis refers to the social need of the implementation of electrochemical sensors in our daily life at different levels. From a sanitary point of view, the use and real application of user-friendly platforms by the patient itself would facilitate the decision-making process thanks to the obtaining of relevant information and monitoring of a disease. Besides, the use of these tools individually, in health centers or even hospitals, would reduce the cost that healthcare must pay on a daily basis. In a different approach, this type of sensors can also offer other types of applications, which can be applied for environmental or safety purposes. The manufacturing of electrochemical sensors (amperometric and potentiometric) integrated and embedded on different substrates easy to manipulate, low cost and robust (such as textiles, balloons or paper) has been achieved during this thesis. The study of their analytical performance under different mechanical stress and using different biological fluids (detecting ions in sweat or glucose in serum and blood) has also been carried out successfully. These technological contributions are aimed at overcoming the challenges that today's society needs to solve: such as the sustainability of the health system in an aging population; the maintenance of security and general wellbeing; and environmental control. This thesis contributes with huge advancements to face these issues and shows different scientific solutions and useful tools for these challenges that society needs to address. This thesis refers to the social need of the implementation of electrochemical sensors in our daily life at different levels. From a sanitary point of view, the use and real application of user-friendly platforms by the patient itself would facilitate the decision-making process thanks to the obtaining of relevant information and monitoring of a disease. Besides, the use of these tools individually, in health centers or even hospitals, would reduce the cost that healthcare must pay on a daily basis. In a different approach, this type of sensors can also offer other types of applications, which can be applied for environmental or safety purposes. The manufacturing of electrochemical sensors (amperometric and potentiometric) integrated and embedded on different substrates easy to manipulate, low cost and robust (such as textiles, balloons or paper) has been achieved during this thesis. The study of their analytical performance under different mechanical stress and using different biological fluids (detecting ions in sweat or glucose in serum and blood) has also been carried out successfully. These technological contributions are aimed at overcoming the challenges that today's society needs to solve: such as the sustainability of the health system in an aging population; the maintenance of security and general wellbeing; and environmental control. This thesis contributes with huge advancements to face these issues and shows different scientific solutions and useful tools for these challenges that society needs to address.
27
Udina, Oliva Sergi. "Smart Chemical Sensors: Concepts and Application." Doctoral thesis, Universitat de Barcelona, 2012. http://hdl.handle.net/10803/84079.
Full textAbstract:
This PhD thesis introduces basic concepts of smart chemical sensors design, which are afterwards applied to a particular application: the analysis of natural gas.
The thesis addresses thus two sets of objective, a first set of objectives related to the conceptual design of a smart chemical sensor using smart sensor standards:
- The design of an optimal smart chemical sensor architecture
- The novel combination in a working prototype of the highly complementary smart sensor standards IEEE-1451 and BS-7986
A second set of objectives is directly related to the selected application. Natural gas quality control. Natural gas is an energy source of major importance in the world energy supply, its quality control is increasingly important due to its origin-dependent properties and the progressive liberalization of the energy market. The objectives related to this application are:
- To solve the natural gas quality analysis problem by using a lower cost approach taking advantage of MEMS technology, smart sensor features, and embedded intelligent signal processing.
- To select suitable sensing technologies and associated signal processing.
An overall goal addressed by the PhD Thesis is in the end the reporting of a working smart sensor prototype implementing all the smart sensor features, MEMS based natural gas analysis and advanced signal processing as a demonstration of a novel low-cost and high speed natural gas analyzer.
The thesis covers this research along 7 chapters, introducing the concepts and application in chapters 1 and 2, the objectives in chapter 3, the simulation of a proposed MEMS sensor approach in chapter 4, the description of the advanced signal processing approach adopted in chapter 5, the description of the electronics and engineering of the smart natural gas analyzer prototype in chapter 6, and finally the conclusions of the work in chapter 7.La tesis introduce conceptos básicos sobre el diseño de sensores químicos inteligentes, en particular presenta los estándares propuestos IEEE-1451 y BS-7986, y elabora una propuesta para el diseño óptimo de dichos sensores químicos inteligentes. Se implementa la propuesta de diseño para una aplicación concreta, el análisis de gas natural. Además de la aplicación de los conceptos sobre sensores químicos inteligentes se pretende además diseñar un analizador compacto, rápido y de bajo coste, para ello se estudia el uso de un microsensor termoeéctrico como sensor principal del analizador. Una vez probada su viabilidad se implementan ambos conceptos (sensores inteligentes y microsensor termoeléctrico) en un prototipo funcional validado en laboratorio. Como resultado se obtiene una propuesta para el diseño de sensores químicos inteligentes basada en estándares, y por otro lado se presenta un nuevo analizador de gas natural, más rápido y compacto que los existentes. Los resultados obtenidos originan diversas publicaciones en revistas así como dos patentes de método y sistema.
28
Novell, Recasens Marta. "Paper-based potentiometric platforms for decentralised chemical analysis." Doctoral thesis, Universitat Rovira i Virgili, 2015. http://hdl.handle.net/10803/313994.
Full textAbstract:
En les darreres dècades, el món ha experimentat profunds canvis socials i tecnològics. Entre aquests, són destacables les tendències emergents d’anàlisis descentralitzats i de xarxes de sensors, que estan tenint un gran impacte en moltes àrees, especialment en el sistema sanitari. El desenvolupament d’eines per a realitzar anàlisis fora del laboratori de forma robusta, simple i econòmica, serà de gran ajuda per generar, per exemple, eines de diagnòstic assequibles. Per complementar aquestes tendències, aquesta tesis presenta el desenvolupament d’una eina analítica nova per anàlisis descentralitzats, usant paper modificat amb nanotubs de carboni com a substrat i la potenciometria com a tècnica de detecció. Els nanotubs de carboni s’han incorporat amb èxit sobre un paper de filtre convencional, convertint-lo així en conductor, i proporciona’t-li habilitat transductora ió-electró. Amb aquesta plataforma s’han desenvolupat elèctrodes selectius de ions per a diferents ions –mantenint el mateix rendiment analític que els elèctrodes convencionals- així com també un elèctrode de referència. La demostració de que aquesta plataforma pot solucionar un problema analític s’ha dut a terme a través del desenvolupament d’una cel·la potenciomètrica complerta de paper per a la detecció de liti en sang. Aquests elèctrodes també han estat combinats amb èxit amb un potenciòmetre d’identificació per radiofreqüència (RFID), cosa que permet el seu ús de forma descentralitzada. Altres aplicacions possibles, juntament amb les limitacions del sistema es discuteixen en detall. En definitiva, aquest treball obre la possibilitat de substituir sensors convencionals per aquesta plataforma més econòmica, obrint així tota una nova gama d’oportunitats.En las últimas décadas, el mundo ha experimentado profundos cambios sociales y tecnológicos. Entre los cuáles son destacables las tendencias emergentes de análisis descentralizados y de redes de sensores, que tienen un gran impacto en muchas áreas, especialmente en el sistema sanitario. El desarrollo de herramientas para realizar análisis fuera del laboratorio de forma robusta, simple i económica, será de gran ayuda per generar, para generar, herramientas de diagnóstico asequibles. Para complementar estas tendencias, esta tesis presenta el desarrollo de una herramienta analítica nueva para análisis descentralizados, usando papel modificado con nanotubos de carbono como sustrato y la potenciometría como técnica de detección. Los nanotubos de carbono se han incorporado con éxito sobre un papel de filtro convencional, convirtiéndolo así en conductor, y proporcionándole habilidad transductora ion-electrón. Con esta plataforma se han desarrollado electrodos selectivos de iones para distintos iones manteniendo el mismo rendimiento analítico que los electrodos convencionales- así como también un electrodo de referencia. La demostración de que esta plataforma puede solucionar un problema analítico se ha hecho a través del desarrollo de una celda potenciométrica completa de papel para la detección de liti en sangre. Estos electrodos también se han combinado con éxito con un potenciómetro de identificación por radiofrecuencia (RFID), cosa que permite su uso de forma descentralizada. Otras aplicaciones posibles, junto con las limitaciones sistema se discuten en detalle. En definitiva, este trabajo abre la posibilidad de substituir los sensores convencionales por esta plataforma más económica, abriendo así tota una nueva gama de oportunidades.
During the last decades, the world has undergone deep social and technological changes. Remarkably are the emerging trends of decentralised analysis and sensing networks, which are having a deep impact in many areas, especially in the healthcare system. The development of tools for performing measurements out of the lab in a robust, simple and cost-effective way will be of great help to generate, for example, affordable diagnostic tools. To complement this trends, this thesis presents the development of a novel analytical tool for decentralised measurements, by using paper as a substrate modified with carbon nanotubes (CNT), and potentiometry as detection approach. CNTs have been successfully incorporated over a conventional filter paper making it conductive, and giving to it ion-to-electron transduction capability. Over this platform ion-selective electrodes for different ions have been developed –keeping the same analytical performance as conventional electrodes- as well as a reference electrode. The demonstration that this platform can solve an analytical problem has been proved through the development of a complete paper cell for the detection of lithium in blood. This electrodes have been also combined with a radio frequency identification (RFID) potentiometer, which will allows its use in a decentralised way. Other possible application of this platform together with its limitations are also discussed. All in all, this work opens the possibility to substitute conventional sensors for this low-cost paper sensors, thus unlocking a whole new range of possibilities.
29
Seo, Jae Hyeong. "Silicon-Based Resonant Microsensor Platform for Chemical and Biological Applications." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/19835.
Full textAbstract:
The main topic of this thesis is the performance improvement of microresonators as mass-sensitive biochemical sensors in a liquid environment. Resonant microstructures fabricated on silicon substrates with CMOS-compatible micromachining techniques are mainly investigated. Two particular approaches have been chosen to improve the resolution of resonant chemical/biochemical sensors. The first approach is based on designing a microresonator with high Q-factor in air and in liquid, thus, improving its frequency resolution. The second approach is based on minimizing the frequency drift of microresonators by compensating for temperature-induced frequency variations.
A disk-shape resonant microstructure vibrating in a rotational in-plane mode has been designed, fabricated and extensively characterized both in air and in water. The designed resonators have typical resonance frequencies between 300 and 1,000kHz and feature on-chip electrothermal excitation elements and a piezoresistive Wheatstone-bridge for vibration detection. By shearing the surrounding fluid instead of compressing it, damping is reduced and quality factors up to 5800 in air and 94 in water have been achieved. Short-term frequency stabilities obtained from Allan-variance measurements with 1-sec gate time are as low as 1.1 10-8 in air and 2.3 10-6 in water. The performance of the designed resonator as a biological sensor in liquid environment has been demonstrated experimentally using the specific binding of anti-beta-galactosidase antibody to beta-galactosidase enzyme covalently immobilized on the resonator surface.
An analytical model of the disk resonator, represented by a simple harmonic oscillator, has been derived and compared with experimental results. The resonance frequency and the Q-factor of the disk resonator are determined from analytical expressions for the rotational spring constant, rotational moment of inertia, and energy loss by viscous damping. The developed analytical models show a good agreement with FEM simulation and experimental results and facilitate the geometrical optimization of the disk-type resonators.
Finally, a new strategy to compensate for temperature-induced frequency drifts of resonant microstructures has been developed based on a controlled stiffness modulation by an electronic feedback loop. The developed method is experimentally verified by compensating for temperature-induced frequency fluctuations of a microresonator. In principle, the proposed method is applicable to all resonant microstructures featuring excitation and detection elements.
30
Ferner, Matthew C. "Environmental Modification of Chemosensory Interactions between Predators and Prey: The World According to Whelks." Diss., Connect to this title online, 2006. http://etd.gatech.edu/theses/available/etd-04102006-140436/.
Full textAbstract:
Thesis (Ph. D.)--Georgia Institute of Technology, 2006.Title from PDF t.p. (viewed on Oct. 28, 2006). Weissburg, Marc, Committee Chair ; Dusenbery, David, Committee Member ; Hay, Mark, Committee Member ; Webster, Donald, Committee Member ; Blanton, Jackson, Committee Member. Includes bibliographical references (p. 108-119).
31
Guinovart, Pavón Tomàs de Aquino. "Addressing emerging paradigms in chemical analysis: new platforms for wearable and decentralized sensors." Doctoral thesis, Universitat Rovira i Virgili, 2015. http://hdl.handle.net/10803/401830.
Full textAbstract:
L’objectiu principal d’aquesta tesi és l’exploració de noves fronteres en l’àrea de sensors químics. Primerament, a través del desenvolupament de nous enfocs per construir sensors químics vestibles. Seguidament, a través de la generació de noves maneres de sensar electròlits en mostres reals. La potenciometria i la detecció òptica seran les tècniques utilitzades.
L’ús de la potenciometria cap al 1900, amb els elèctrodes selectius de ions (ESI), ha anat canviant i la revolució va començar amb la miniaturització d’aquests ESI amb l’aparició de la necessitat de sensors per monitoritzar el nostre estat de salut, juntament amb la tendència de desenvolupar sensors vestibles. Aquesta tesi, llavors, ha estat el punt d’inici per al desenvolupament de sensors incorporats en plataformes vestibles, per acabar mesurant electròlits en fluids biològics.
També, aquesta tesi s’ha focalitzat en la millora de les membranes selectives polimèriques, específicament per un analit. Durant la última dècada, hi ha hagut un avenç considerable i recerca de nous receptors per molècules clínicament rellevants present en el nostre cos. Per exemple, la introducció d’un nou receptor artificial (calix[4]pyrrole) per creatinina ha sigut un resultat molt important d’aquesta tesi. La creatinina és la segona molècula més detectada rutinàriament analitzada després de la glucosa, fet el qual probablement pot obrir la porta cap al mercat després d’aquesta tesi.
Finalment, la potenciometria no ha estat l’única tècnica utilitzada en aquesta tesi, sinó que també s’ha utilitzat la tècnica òptica. El repte més important, demostrat en aquesta tesi, és la detecció d’anions difícilment detectables amb la potenciometria, com per exemple l’anió sulfat.El objetivo principal de esta tesis es la exploración de nuevas fronteras en el área de sensores químicos. Primeramente, a través del desarrollo de nuevos enfoques para construir sensores químicos vestibles. Seguidamente, a través de la generación de nuevas maneras de sensar electrolitos en muestras reales. La potenciometría y la detección óptica serán las técnicas utilizadas. El uso de la potenciometría allá en el 1900, con los electrodos selectivos de iones (ESI), ha seguido un proceso de cambio y la revolución empezó con la miniaturización de estos ESI con la aparición de la necesidad de sensores para monitorizar nuestro estado de salud, juntamente con la tendencia de desarrollar sensores vestibles. Esta tesis, entonces, ha sido el punto de inicio para el desarrollo de sensores incorporados en plataformas vestibles, para medir electrolitos en fluidos biológicos. También, esta tesis se ha focalizado en la mejora de las membranas selectivas poliméricas, específicamente para un analito. En la última década, ha habido un avance considerable e investigación de nuevos receptores para moléculas clínicamente relevantes presentes en nuestro cuerpo. Por ejemplo, la introducción de un nuevo receptor artificial (calix[4]pyrrole) para creatinina ha sido un resultado muy importante para esta tesis. La creatinina es la segunda molécula más detectada rutinariamente analizada después de la glucosa, hecho que probablemente puede abrir la puerta al mercado después de la tesis. Finalmente, la potenciometría no ha sido la única técnica utilizada en esta tesis, sino que también se ha utilizado la técnica óptica. El reto más importante, demostrado en esta tesis, es la detección de aniones difícilmente detectables con la potenciometría, como per ejemplo el anión sulfato.
The main objective of this thesis is the exploration of new frontiers in the area of chemical sensors. First, through the development of novel approaches to build wearable chemical sensing devices. Second, through the generation of new sensing approaches to determine electrolytes in liquid samples. Potentiometry as well as optical detection techniques will be used. Since potentiometry was firstly used at the beginning of 1900, with classical ion-selective electrodes (ISEs), this technique have constantly been changing and the revolution of this technique started with the miniaturization of these ISEs in combination with the real need of sensors for monitoring our health status, which has merged in a new trend to develop wearable sensors. This thesis has, then, been the starting point to develop potentiometric sensors embedded in wearable platforms, being finally used for measuring electrolytes in biological fluids. Also, this thesis has been focused on the improvement of the ion-selective polymeric membrane sensitive to one specific electrolyte. In the last decade, there has been a considerable advance and research of new receptors for clinically relevant molecules present in our body. For example, the introduction of a new artificial receptor (calix[4]pyrrole) for creatinine has been a significant milestone in this thesis. Creatinine is the second most important molecule routinely analyzed after glucose, thus likely to open a path to the market beyond this thesis. Finally, potentiometry has not been the only technique used in this thesis but also optical technique. The real challenge, overcome in this thesis, has been to sense anions selectively, especially the ones that currently are hardly measured with potentiometry, such as for example sulphate.
32
Gonçalves, Vanessa Cristina. "Síntese e caracterização de derivados do politiofeno para utilização em sensores." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/88/88131/tde-12052010-154710/.
Full textAbstract:
Os polímeros conjugados, principalmente da classe dos politiofenos, despontaram como materiais alternativos para a obtenção de camadas quimicamente seletivas em sensores de gases. Dentre as principais vantagens desses materiais estão a possibilidade de obtenção de dispositivos sensores que operem à temperatura ambiente e a diversidade de materiais. Assim, por exemplo, com uma simples modificação da cadeia lateral do politiofeno pode-se obter materiais com diferentes afinidades químicas, o que pode contribuir para a melhora da seletividade desses dispositivos. A seletividade e a sensibilidade são as maiores limitações práticas dos sensores de gases que utilizam os polímeros conjugados como camadas sensoras. Neste trabalho, diferentes derivados do politiofeno foram sintetizados via polimerização oxidativa com cloreto férrico e caracterizados químico-estruturalmente por FTIR, RMN 1H, HPSEC e análise térmica (TG). Filmes desses polímeros foram obtidos pelas técnicas spin-coating e casting, sendo que a escolha da técnica de preparo foi baseada na solubilidade desses polímeros em clorofórmio. Foi demonstrado que as características superficiais e as propriedades de absorção no Uv-vis e de emissão dos filmes desses politiofenos são influenciadas pelos tipos de cadeias laterais presentes nesses polímeros. Esses filmes foram também utilizados no estudo das suas propriedades sensoras óticas e elétricas para a detecção de VOCs e umidade, sendo demonstrado que os sensores óticos são menos sensíveis aos analitos propostos do que os sensores elétricos, apresentando valores de sensibilidades no intervalo de 10-7 a 10-5 ppm-1, respectivamente, com algumas exceções. As respostas de ambos os tipos de sensores contendo PHT foram qualitativamente e quantitativamente reprodutíveis, entretanto, as características de reprodutibilidade dos sensores elétricos de PHT apresentaram grande influência das condições elétricas iniciais de seus filmes. Diferentes padrões de detecção foram apresentados para as detecções óticas e elétricas de um determinado polímero, demonstrando que estes polímeros são bons candidatos para serem utilizados como camadas ativas em dispositivos de detecção de VOCs (compostos orgânicos voláteis).The conjugated polymers, especially polythiophenes, have emerged as alternative materials to obtain chemically selective layers in gas sensors. The main advantages of these materials are the possibility of obtaining sensing devices that operate at room temperature and the diversity of materials. For example, a simple modification of the side chain of polythiophene can provide materials with different chemical affinities, which can contribute to the improvement of the selectivity of these devices. The selectivity and sensitivity are the main practical limitations of the gas sensors containing conjugated polymers as sensing layers. In this study, different polythiophene derivatives have been synthesized by oxidative polymerization with ferric chloride and characterized by FTIR, 1H NMR, HPSEC and thermal analysis (TG). Films of these polymers have been obtained by spin-coating techniques and casting, depending on their solubility in chloroform. It has been shown that the surface characteristics and the properties of absorption in the UV-vis and the emission of the films of these polythiophene derivatives are dependent on the type of side chain attached to the thiophene ring. These films have been used in the study of their optical and electrical sensing properties of VOCs and humidity, and it has been demonstrated that optical sensors are less sensitive to these analytes than the electrical ones. Their fractional sensitivities are 10-7 and 10-5 ppm-1, respectively, with some exceptions. The responses of such sensors have been qualitatively and quantitatively reproducible, however, the responses of electrical sensors showed influence of the initial electrical characteristics of the films. Different detections patterns were showed for optical and electrical detections of a particular polymer, showing that these polymers are good candidates to be used as active layers in sensing devices to detect VOCs.
33
Rajan, Parthiban. "Novel Capacitive Sensors for Chemical and Physical Monitoring in Microfluidic Devices." Ohio University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1549449776383119.
Full text
34
Engel, Nicholas Alexander. "Functionalization and Characterization of Chemical Vapor Deposited Graphene Sheets Towards Application in Chemical Vapor Sensing." Wright State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=wright1537276723534983.
Full text
35
McCulloch, Scott. "Fibre optic microsensors for intracellular chemical measurements." Thesis, University of Strathclyde, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.248617.
Full text
36
Choudhury, Arnab. "A piezoresistive microcantilever array for chemical sensing applications." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/26623.
Full textAbstract:
Thesis (Ph.D)--Mechanical Engineering, Georgia Institute of Technology, 2008.Committee Chair: Hesketh, Peter; Committee Member: Bottomley, Lawrence; Committee Member: Degertekin,Levent; Committee Member: Hu, Zhiyu; Committee Member: Janata, Jiri; Committee Member: Zhang, Zhoumin. Part of the SMARTech Electronic Thesis and Dissertation Collection.
37
Su, Jin Jyh. "Integrated low-power interfaces for impedimetric chemical sensors." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/54288.
Full textAbstract:
This thesis presents two interface circuits for impedimetric chemical sensors: one for passive chemical sensors and the other for ChemFETs. Both interfaces were fabricated in 0.35μm BiCMOS technology and provide the same output data rate of 1Hz.
The interface for passive impedimetric sensors is reconfigurable for performing either resistance or capacitance measurements and provides a fully digital output with less than 81.8μW power consumption at VDD = 2.5V. The interface features a 176dB resistance dynamic range (31.6Ω-200MΩ, <±0.8% nonlinearity, and >40dB SNR) realized with only two sub-ranges to minimize calibration efforts and a 102dB capacitance dynamic range (0.8-1000pF, <±0.2% nonlinearity, and >40dB SNR).
The ChemFET interface is a highly versatile system that can generate a wide range of bias voltages (VG up to 9.74V and VD up to 16.3V depending on the measurement modes) and perform either constant voltage or constant current mode measurement. At maximum rated output (VG = 9.74V, VD = 16.3V, and IDS = 15μA), the interface consumes only 2.02μW at VDD = 3.3V and provides analog readout noise levels of 0.0476μARMS at 10μA and 0.503mVRMS for IDS and VT, respectively.
Besides attempting versatile system architectures, detailed noise and efficiency analysis were performed for the passive sensor interface and the ChemFET interface, respectively. The noise analysis suggests that different types of noise (correlated or uncorrelated) dominate the noise performance in different measurement ranges and, thus, noise suppression techniques, such as chopper stabilization, correlated double sampling (CDS), and oversampling/averaging, are applied to adequate parts of the interface system. The efficiency analysis of the boost capacitor charger in the ChemFET interface concludes that applying a moderate pulsewidth (200-300ns) to drive the boost converter yields the best efficiencies for charging a capacitor.
Compared to interfaces described in the literature, the proposed interface for passive sensors achieves better versatility and wide dynamic range with less number of sub-ranges and power consumption. The proposed interface for ChemFETs achieves wider voltage supply range at very low power level.
In-house fabricated chemical sensors, including passive chemical sensors and ChemFETs, were interfaced with the developed circuits and gas-phase chemical measurements with the systems were demonstrated. The novel passive chemical sensor tested in this thesis employs a multi-functional design, which can be configured into either a chemoresistor or a chemocapacitor; the tested ChemFET employs a bottom-gate TFT structure to allow the semiconducting film to interact with the analytes.
38
Li, Guofeng. "Electrochemical functionalization of conducting polymers towards chemical sensing applications." Diss., Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/30313.
Full text
39
Truax, Stuart. "A microscale chemical sensor platform for environmental monitoring." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/45780.
Full textAbstract:
The objective of this research is to apply micromachined silicon-based resonant
gravimetric sensors to the detection of gas-phase volatile organic compounds (VOCs). This
is done in two primary tasks: 1) the optimization and application of silicon disk resonators
to the detection of gas-phase VOCs, and 2) the development and application of a novel
gravimetric-capacitive multisensor platform for the detection of gas-phase VOCs.
In the rst task, the design and fabrication of a silicon-based disk resonator structure
utilizing an in-plane resonance mode is undertaken. The resonance characteristics of the
disk resonator are characterized and optimized. The optimized characteristics include the
resonator Q-factor as a function of geometric parameters, and the dynamic displacement
of the in-plane resonance mode. The Q-factors of the disk resonators range from 2600 to
4360 at atmosphere for disk silicon thicknesses from 7 µm to 18 µm, respectively.
The resonance frequency of the in-plane resonance mode ranges from 260 kHz up to 750 kHz.
The disk resonators are applied to the sensing of gas-phase VOCs using (poly)isobutylene
as a sensitive layer. Limits of detection for benzene, toluene and m-xylene vapors of 5.3
ppm, 1.2 ppm, and 0.6 ppm are respectively obtained. Finally, models for the limits of
detection and chemical sensitivity of the resonator structures are developed for the case of
the polymer layers used.
In the second task, a silicon-based resonator is combined with a capacitive structure
to produce a multisensor structure for the sensing of gas-phase VOCs. Fabrication of the
multisensor structure is undertaken, and the sensor is theoretically modeled. The baseline
capacitance of the capacitor component of the multisensor is estimated to be 170 fF. Finally,
initial VOC detection results for the capacitive aspect of the sensor are obtained.
40
Evans, Phillip. "The investigation of colloidal based conducting polymer films for chemical sensor applications." Thesis, University of the West of England, Bristol, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.284917.
Full text
41
Smith, Ann M. "Optical and related methods of chemical sensing using substituted phthalocyanines." Thesis, University of Kent, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.319229.
Full text
42
Chen, Weihua. "Chemical Sensors Based on Fluorescence Turn-On Mechanism by Using Excited State Intramolecular Proton Transfer." University of Akron / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=akron1334772708.
Full text
43
Wild, Kirstie Yvette. "Redox-active host molecules for the electrochemical recognition of charged and neutral species." Thesis, University of Oxford, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.358700.
Full text
44
Johnson, Simon. "Field effect transistor type sensors." Thesis, Cardiff University, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.259174.
Full text
45
Fneer, Mohamed K. "Development of fibre optic based ammonia sensor for water quality management." Thesis, City University London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.363350.
Full text
46
O'Rourke, Jaqueline Karen. "Surface and bulk studies of iron phthalocyanine based gas sensors." Thesis, Sheffield Hallam University, 1994. http://shura.shu.ac.uk/20152/.
Full textAbstract:
Phthalocyanines films have been noted for their use as chemical sensors by measuring changes in conductivity when a gas is adsorbed at the surface. The sensing mechanism is not well understood. This work uses iron phthalocyanine as a model in an attempt to understand the gas sensing mechanism of metal phthalocyanines. The alpha and beta polymorphs of iron phthalocyanine (FePc) have been synthesised and then studied using infra-red spectroscopy, scanning electron microscopy (SEM), gas sensing experiments and Mossbauer spectroscopy. Infra red spectroscopy indicates that a phase change occurs at 205°C and SEM work confirms this since the microcrystallite size changes at this temperature. Gas sensing work has shown that FePc responds to NO[2] and Cl[2] at room temperature. Variable temperature transmission mode Mossbauer spectroscopy of both phases showed that the alpha phase has a lower recoil free fraction at room temperature than the beta phase suggesting that the beta phase has a more rigid structure i.e. it is less free to vibrate in the lattice than the alpha phase. This also explains the difficulties experienced in attempts to collect backscatter spectra from alpha FePc. Backscatter Mossbauer spectroscopy has been used in vitro to show a difference at ambient temperature and pressure, of beta FePc before and after exposure to a gas. Conversion electron Mossbauer spectroscopy indicates that NO[2] adsorbs on to the surface of the FePc film preventing the escape of conversion electrons, and conversion x-ray experiments have shown that the NO[2] penetrates the near surface causing a chemical change.
47
Lei, Hua. "Modeling and Data Analysis of Conductive Polymer Composite Sensors." Diss., CLICK HERE for online access, 2006. http://contentdm.lib.byu.edu/ETD/image/etd1577.pdf.
Full text
48
Patterson, Mark Alan. "A Passive Wireless Platform for Chemical-Biological Sensors." University of Dayton / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1353859776.
Full text
49
Lima, John Paul Hempel. "Um nariz eletrônico baseado em polímeros condutivos." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/3/3140/tde-12112013-103024/.
Full textAbstract:
O estudo de sistemas voltados para a detecção e discriminação de compostos e substâncias gasosas tem se destacado nas áreas da nanociência e da nanotecnologia devido ao grande interesse no controle de odores e aromas presentes em alimentos, cosméticos e no meio ambiente. Dentre os diversos tipos de sensores matriciais de gases, conhecidos como narizes eletrônicos, os feitos à base de polímeros vêm se destacando devido ao baixo custo, fácil processabilidade, operação em temperatura ambiente e boa resposta sensorial. O presente trabalho mostra a confecção e análise de sensores poliméricos e um nariz eletrônico de pequenas dimensões, portátil e de baixo custo baseado em polímeros condutivos. Como materiais ativos dos sensores foram estudados materiais pertencentes à classe das polianilinas, politiofenos, polipirrol e ftalocianina de níquel, depositados por duas técnicas diferentes: spin coating e automontagem. As análises da espessura, reprodutibilidade e estabilidade elétrica mostraram diferenças em relação aos materiais empregados e a técnicas escolhidas, em que a uniformidade superficial não está associada diretamente com a estabilidade elétrica. Sensores que empregam PAni e POMA sofrem variação da resistência elétrica em função do tempo, o que está relacionado com a perda de dopagem desses materiais. O projeto e desenvolvimento de uma câmara de medidas são relatados com simulações que mostraram o perfil adequado para o posicionamento dos sensores. Para nortear a concepção do nariz, foi realizado um comparativo entre resistência e capacitância elétricas como parâmetros de interrogação mostrando resultados similares na discriminação, mas com diferenças de 100 vezes em valor relativo, o que resultou na escolha da resistência elétrica. O nariz eletrônico concebido apresenta poder de discriminação não só comparável ao da técnica de cromatografia gasosa, como também permite discriminar diversos tipos de analitos: perfumes, álcool etílico puro e adulterado, sucos de maçã, vinhos, cachaças e cachaças adulteradas e mel, tanto através da técnica de PCA quanto por redes neurais artificiais. O emprego de uma elipsóide como selecionador da região das classes facilitou o processo de visualização e análise dos dados enquanto que o uso de redes neurais mostrou classificações corretas próximas a 100% para praticamente todos os analitos.The study of sensors for detection and discrimination of gaseous substances and compounds have been gaining much attention in areas such as nanocience and nanotechnology due to the great motivation in control of odors and substances associated with food, cosmetics and environment. Within several types of gas sensor arrays, known as electronic noses, polymeric-made ones distinguishes due to good sensory response, can be utilized at ambient temperature, are able to be easily processed and are of potential low cost. This work shows the fabrication and analysis of polymeric sensors and a small size, low cost and portable electronic nose. Polymeric materials belonging to polyaniline, polythiophene and polypyrrole classes and nickel phtalocyanines, deposited by two different techniques (spin coating and self assembly) were studied as active materials for the sensors. Analysis of thickness, reproducibility and electrical stability were performed and they showed differences among the studied materials and deposition techniques, where superficial uniformity is not associated directly with electrical stability. Sensors with PAni and POMA showed an electrical resistance variation in function of time which is related to dopant loss. Project and development of an analysis chamber are reported with simulations that showed an adequate profile for sensor positioning. A comparison between resistance and capacitance was performed aiming the electronic nose conceptualization. Both parameters showed similar discrimination capability but a 100 times difference in relative variation, leading to the choice of the electrical resistance. The conceived electronic nose shows a discrimination capability similar to gas chromatography and also allows the discrimination of many different analyte types: perfumes, pure and adulterated ethanol, apple juices, wines, pure and adulterated cachaças and honey, either with PCA technique or as well with artificial neural networks. The use of an ellipsoid to envelop class regions ease the visualization process and data analysis from PCA results while neural networks showed correct classifications near to 100% for almost all analytes.
50
Zhan, Wei. "Integration of functional components into microfluidic chemical systems: bioimmobilization and electrochemiluminescent detection on-chip." Diss., Texas A&M University, 2003. http://hdl.handle.net/1969.1/2206.
Full textAbstract:
We have investigated and implemented several general strategies in the development of microfluidics-based chemical/biochemical sensing systems. The research in this dissertation covers the immobilization of biological reagents inside microfluidic channels using polystyrene (PS) microbeads and photopolymerizable hydrogel, electrochemical sensing via electrochemiluminescence (ECL) reporting with bipolar and two-electrode configurations, and integration of these general functions to realize multiplexing and networking on-chip. Photopolymerizable hydrogel based on Poly(ethylene glycol) (PEG) and streptavidin-coated polystyrene (PS) microbeads were employed as building blocks as well as functional components in microfluidic system. PEG hydrogels can be used to define local microenvironments at different locations in the same microchannel, which enables the introduction of multiple sensing events on the same device. Monitoring of DNA hybridization and enzyme/substrate interaction were realized thereafter by using either fluorescence or electrochemistry as the detection method. Electrogenerated chemiluminescence based on Ru(bpy)32+ (bpy = 2,2??-bipyridine) and tripropylamine (TPA) was used to photonically report various redox events in microfluidic systems. By using microfluidic electrochemical cells based on either two-electrode or bipolar electrode (one-electrode), electroactive species that undergo reduction can be electrically linked to this anodic ECL process and thus be reported by the latter. This ECL sensing scheme essentially broadens the spectrum of redox compounds that can be detected by ECL since the analytes are not required to directly participate into the light-generating processes. Microfluidics offers some unique technical advantages of performing electrochemistry over conventional methods. In particular, laminar flow allows multiple analyte streams to be brought together in parallel with little mixing. Moreover, electrochemical signals can be generally utilized as a convenient means to link individual microchannels together hence to realize microfluidic networking and cross-communication. Electrochemical microfluidic devices can be used to mimic general functions of microelectronic devices such as diodes, transistors, and logic gates. These novel functions rendered by electrochemistry are believed to bring us closer to the final goals of micro total analysis systems and lab-on-a-chip.