• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 5
  • 1
  • 1
  • 1
  • Tagged with
  • 9
  • 3
  • 3
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

An Investigation of the Polarization States of Light Reflected from Scarab Beetles of the Chrysina Genus / En undersökning av polarisationstillståndet för ljus reflekterat från skalbaggar avsläktet Chrysina

Fernandez del Rio, Lia January 2011 (has links)
The polarization behaviour for six species of Scarab beetles from the Chrysina genus is investigated with Mueller Matrix Spectroscopic Ellipsometer (MMSE). The m41 element of the matrix, which is related to the circular polarization behaviour, is analysed. The ellipticity, degree of polarization and azimuth angle are also presented to get a better understanding of the polarization effect. The measurements were done with a dual rotating compensator ellipsometer. The measured wavelength region was from 240 to 1000 nm and the angle of incidence from 25° to 75° in most of the cases. In general very high ellipticities (near circular) are reported. All specimens studied reflect both right- and left-handed polarized light. Depending on the species, two general types of polarization behaviour were observed. Chrysina macropus and Chrysina peruviana showed m41 values close to 0. Green stripes on Chrysina gloriosa showed similar polarization behaviour whereas gold stripes on the same beetle had much more pronounced m41 variations. Large m41 variations were also observed for Chrysina argenteola, Chrysina chrysargyrea and Chrysina resplendens. Four specimens of Chrysina resplendens show different m41 patterns suggesting differences in their structures.
2

An Investigation of the Polarizing Properties and Structural Characteristics in theCuticles of the Scarab Beetles Chrysina gloriosa and Cetonia aurata

Fernández del Río, Lía January 2012 (has links)
Light reflected from the scarab beetles Cetonia aurata (C. aurata) and Chrysina gloriosa (C. gloriosa) has left-handed polarization. In this work the polarizing properties and structural characteristics of the cuticles of these two beetles are investigated with two different techniques: scanning electron microscopy (SEM) and Mueller-matrix spectroscopic ellipsometry (MMSE). SEM is used to get cross section images of the epicutucle and the endocuticle. Thicknesses around 18 μm were measured for both layers for C. aurata and between 12 and 16 μm for C. gloriosa. A layered structure is observed in both beetles. In addition, a cusp-like structure is also observed in C. gloriosa. MMSE showed left-handed near-circular polarization of light reflected on both beetles. For C. aurata this is observed in a narrow wavelength range (500-600 nm) and for C. gloriosa in a wider wavelength range (400-700 nm) when measured on golden areas of the cuticle. C. gloriosa also has green areas where the reflected light was linearly polarized. The results are used in regression modelling. A good model approximation was found for C. aurata for angles up to 60 whereas a good starting point for future work was reached for C. gloriosa.
3

Characterisation of Proteinase Inhibitors from Canegrubs for Possible Application to Genetically Engineer Pest-Derived Resistance into Sugarcane

Nutt, Kerry Anne January 2005 (has links)
In 1931, Mungomery stated "whitegrubs have been for years past, and still are, the worst insect problem confronting the sugar industry". This statement remains true to this day, with canegrubs costing the Australian sugar industry A$7.22 million in lost production and in use of insecticides. The development of a sugarcane cultivar with resistance to canegrub attack would be a valuable addition to the recently implemented canegrub management program. This thesis examined the possibility that natural inhibitors derived from canegrubs could be incorporated in sugarcane to reduce or prevent its destruction by canegrubs. The research described here demonstrated that canegrub haemolymph contains inhibitors with activity against commercially purified enzymes and serine proteases found in crude midgut extracts. A cDNA encoding a potential canegrub protease inhibitor (DA10 12) belonging to the Ascaris family was cloned, but it did not have activity against the major canegrub midgut proteases. This protein does, however, still have potential for modification into a serine protease inhibitor suitable for use as a novel insect resistance transgene. The possibility of using haemolymph derived inhibitors as novel antimetabolites in a canegrub management strategy based on transgenic plants was also explored. The findings suggest that proteins with properties similar to those of DA10 12 will require the presence of a signal peptide and/or codon optimisation for successful expression in sugarcane. The research outlined in this thesis is the first investigation of protease inhibitors in the haemolymph of scarab larvae, and is the first report of an Ascaris family inhibitor that does not inhibit a serine protease.
4

Optical Studies and Micro-Structure Modeling of the Circular-Polarizing Scarab Beetles Cetonia aurata, Potosia cuprea, Liocola marmorata

Gustafson, Johan January 2010 (has links)
The aim of the work presented in this thesis is to contribute to a fundamental understanding of polarizing phenomena in some scarab beetles. The aim is also to study the beetle structures as inspiration in fabrication of artificially sculptured films. The three investigated species Cetonia aurata, Potosia cuprea and Liocola marmorata are of the family Scarabaediae and subfamily Cetoniianae (Guldbaggar). They were all collected at Swedish locations and are the only species of Cetoniinae scarabs in Sweden. This work reports on their optical properties represented by Mueller matrix elements, degree of polarization data and trace curves in the Cartesian complex plane representation of polarized light. From these results we verifyan earlier structural model for the Cetonia aurata and make way for similar models of the other two species. The ellipsometer used in this work is of dual rotating compensator type from which the complete Mueller-matrix for the medium examined can be obtained. The ellipsometric measurements were conducted on the scutellum for four different angles of incidence, 45°, 55°, 65° and 75° over a wave-length range of 245-1000 nm. Common for all examined species is that left polarization is observed in the wavelength range of 400 800 nm. For most of these species the polarization state is close to circular at some wavelengths especially at smaller angles of incidence. In general the degree of polarization is high (above 50%) when the polarization is near-circular. The degree of polarization also shows a clear dependence on the angle of incidence. The earlier model for Cetonia aurata shows a good agreement with the experimental data of this work. The model is also found as a good basis to work from to create models for the other two species.
5

Výskyt a role UV reflektantního zbarvení u listorohých brouků (Coleoptera: Scarabaeidae) / The distribution and role of UV reflectant patterns in Scarab beetles (Coleoptera: Scarabaeidae)

Vlach, Jan January 2021 (has links)
The diploma thesis is focused on the distribution and role of UV reflectant patterns in beetles (Coleoptera) with focus on the family Scarabaeidae. Through a survey of European museum collections, we discovered over 900 species of UV reflectant beetles, of which 850 species were identified as UV reflectant for the first time. The surface structures responsible for UV reflectant patterns in beetles were studied in detail using a scanning electron microscope. We have identified two ways how the UV reflectant patterns occur. The first way: the light rays interact with the internal structure of the cuticular formations or the cuticle itself; the second way: the light rays interact with the surface layer formed by cuticular secretion. Additionally we carried out experiments with live animals, where we investigated the effect of an individual's age on the intensity of UV reflectant patterns and the effect of UV reflectance on reproductive activity. In a pilot study we were able to show that freshly hatched individuals show a higher level of UV reflectance than older individuals.
6

Beneath the raptor’s wings : the avian composition grasping the symbol for eternity in Egypt

Klop, Damian J.R. 03 1900 (has links)
Thesis (MPhil (Ancient Studies)--University of Stellenbosch, 2008. / A particular motif in Egyptian art is that of avians. This is frequently depicted in a significant number and variety of visual sources from the tomb of Tutankhamun (KV 62) (1336-1327 BC) and other find contexts throughout Egyptian history from c. 3000 BC, but is little understood. The motif mostly depicts an avian creature with wings outstretched, talons grasping the Egyptian hieroglyph symbol for eternity (shen). In some instances the avian’s falcon or vulture body or parts of the body is/are replaced with parts of another creature, namely that of a snake, cobra, ram, human, duck, or a hieroglyph sign. A study was undertaken to assess how and why this avian motif was composed and what the function in Egyptian culture was. A manual search of published material for relevant visual sources depicting specific versions of the avian motif was undertaken and selected sources were indexed into a representative graphical database including one hundred and ninety-one items. Textual sources (academic literature and literature from ancient Egypt) were then consulted to support and/or expand on the iconographic, symbolic, and functional aspects of the motif: - At the iconographic level, the historical development and ‘structural dynamics’ of the motif are investigated to deduce the artistic rules that applied to its creation. - At the symbolic level, the symbolic meaning of the artwork is ascertained by theorizing on the meaning of the motif and its parts in an Egyptian context. - At the functional level, the function of the artwork is ascertained by investigating how the motif’s symbolism was intended to be applied to benefit the individual. The results of this research is that the avian motif developed over time according to strict artistic rules; that it symbolized the king, eternity and protection; and that its function was to protect the king in all phases of his existence in a political and mythological context in order to ensure that the he would attain an eternal life in the afterlife. In the mind of the ancient Egyptian this was achieved through the transference of the avian motif’s magical qualities to the user. The intended outcome of this study is to highlight the avian motif’s importance in the context of the ancient Egyptian culture.
7

Les scarabées inscrits et autres amulettes de cœur de l’Égypte ancienne (présentation, corpus, critères de datation, caractéristiques, collections) / Inscribed Scarabs and other Heart Amulets in Ancient Egypt (Presentation, Corpus, Dating criteria, Characteristics, Collections)

Laroche, Claude 06 December 2014 (has links)
Le seul ouvrage dédié exclusivement à ce qu’il est convenu d’appeler « les scarabées de cœur » est signé du Professeur Michel Malaise et date de 1978. Ce livre est depuis cette date la référence en la matière mais, en l’absence d’un corpus, les critères de datation proposés n’y peuvent être ni exhaustifs ni très précis. L’objectif de cette étude était de remédier à ces lacunes.Les scarabées de cœur étaient des amulettes disposées dans la région du cœur de la momie d’un individu, juste après son décès, afin de le protéger contre la trahison possible de son propre cœur. En effet, le défunt devait subir l’épreuve de la pesée du cœur devant un tribunal de dieux présidé par Osiris, mais c’est son cœur qui était interrogé pour savoir quelle avait été la conduite de son propriétaire lors de son passage sur la terre. Les réponses à ces questions conditionnaient l’avenir du défunt dans l’au-delà : la vie éternelle ou l’anéantissement. Pour se concilier les bonnes grâces du cœur, d’autant plus que celui-ci pouvait mentir, les amulettes étaient inscrites d’une prière choisie dans un des chapitres 26 à 30 B du Livre des Morts, suppliant le cœur d’avoir des réponses favorables devant le tribunal.La présente étude a pris huit années pour rassembler un corpus de 1400 scarabées de cœur et autres amulettes ayant la même fonction rituelle, soit probablement plus de 85% de ceux qui sont conservés dans les musées, qui sont désignés ici sous le nom générique d’« amulettes de cœur ». Ce corpus a donné lieu à l’établissement d’une typologie permettant de déterminer des séries d’amulettes présentant des caractèristiques plastiques et épigraphiques semblables qui, croisées avec celles des amulettes de date connue, qui sont soit celles dont les propriétaires sont des personnages historiques soit celles provenant de fouilles bien datées, ont conduit à la détermination de critères de datation objectifs. L’étude présente aussi les clichés de plus de 1200 amulettes avec description, une traduction des textes inscrits et une proposition de datation. / The only book dealing specifically with the so-called “ Heart Scarabs” was written by Professor Michel Malaise and published in 1978. It has remained since the reference on the subject but, due to the unavailibility of a corpus, the datation criteria could not be exhaustive nor accurate. The target of this dissertation was to fill these gaps. The heart scarabs were amulets to be laid on (or in) the mummy of a person just after his death in the heart area, in order to protect him from the possible treachery of his own heart. In effect, the Dead was to be put to the test of the weighing of his heart, in front of a court of gods presided by Osiris, but it was his hesart which was interrrogated in order to know whether its owner had behaved well during his life. The answers to these questions would determine whether he would be granted an eternal life or the nothingness. In order fo gain the heart’s goodwill, especially when it might lie, the amulets were inscribed with a prayer chosen in one of the chapters 26 to 30B of The Book of the Dead. This prayer was begging his heart to make favorable answers to the court.It took eight years to gather a corpus of 1400 heart amulets and others amulets with the same ritual function, called “heart amulets” in this dissertation, a number representing likely more than 85% of the total in existence. The gathering of these amulets made possible an adapted typology to be built, which lead to the determination of series of amulets with similar shape or epigraphic characteristics to be compared with the characteristics of amulets with a known date, which are the ones the owners of which are historical persons or those originating from well dated excavations. This comparison allowed for the determination of objective datation criteria. This memoire finally presents photos of more than 1200 amulets with a description, a translation of the texts and an estimated datation.
8

Waste Heat Driven Membrane Distillation Integrated with Stirling Engine

Talåsen, Jonatan, Bergman Larsson, Niklas January 2022 (has links)
In this thesis, the potential to purify water utilizing waste heat from a unit which stores thermal energy and converts it to electricity is studied. The unit, called TES.POD, is developed by Azelio AB and is in this thesis used as a heat source to drive an air gap membrane distillation (AGMD) unit developed by Scarab Development AB. Heat from the TES.POD and ambient air temperature constitutes a temperature difference over a membrane used as a driving force to vaporize a part of the water that transfer through the membrane, and later condensates as clean distilled water as the contaminations stays in the hot stream of feed water. An analysis has been conducted to determine quasi-steady performance of the combined system for estimating the amount of purified water that can be supplied when the TES.POD unit is in peak electricity discharge mode. The 26 kW of waste heat accessible from the TES.POD is shown to enable two AGMD-modules producing purified water at a production of 7, 1l/h per unit having the feed water at 50°C and cooling water at 25°C. A correlation between the amount of waste heat and distilled water production is determined, as the TES.POD could be configured to produce less electricity and more waste heat at a higher temperature. The correlation showed that an 9% increase in cooling temperature, lead to an 30% increase in pure water output and a 33% decrease in electricity output. The results show that when implementing the two companies’ units together, a system that both provides electricity and distilled water is obtained. This is a system with a high demand, especially in off-grid areas with lack of both resources but with accessible renewable energy sources. Moreover, by using waste heat to purify water, it can also reduce the production cost compared to cases where conventional energy sources are used. The potential revenue of the production was estimated to 673 790 SEK/year with an implementation cost of 93 861 SEK with yearly operational expenses estimated to 14 080 SEK/year. / I detta arbete undersöks möjligheten att rena vatten med spillvärme från ett system vilket lagrar termisk energi och av den producerar elektricitet, när det behövs. Systemet är utvecklat av Azelio AB och har produktnamnet TES.POD. Vattendestillationen utförs med en så kallad air gap membrane distillation (AGMD) modul, utvecklad av Scarab Development AB. Värmen från TES.POD och omgivningstemperaturen utgör, i AGMD-modulen, en temperaturdifferens vilken i sin tur skapar en partielltryckskillnad över membranet. Denna partielltryckskillnad låter en del av det förorenade vattnet som flödar i AGMD-modulen att förångas och passera genom membranet. Föroreningarna stannar kvar i det strömmande vattnet och ångan kondenserar som renat vatten.  Arbetet visar att de 26kW som finns att tillgå i form av spillvärme är tillräckligt för att driva två AGMD-moduler att producera 7,1 l/h destillerat vatten per modul. Detta är under förutsättningar att det förorenade vattnet är 50°C och kylvattnet är 25°C. I rapporten återfinns också ett samband mellan mängden spillvärme och produktionen av destillerat vatten, eftersom TES.POD kan konfigureras till att producera spillvärme vid en högre temperatur. Sambandet visade på att 9% ökning av spillvärmens temperatur motsvarar 30% ökning i produktionen av destillerat vatten och en minskad elektricitetsproduktion på 33%.  Resultatet visar på att integrationen av dessa två produkter bildar ett system som både producerar rent vatten och elektricitet när så önskas. Detta system har till synes en stor efterfrågan, speciellt i områden utanför fast el- och vattennätverk men med goda förnyelsebara energikällor. Dessutom, eftersom vattendestillationen sker med spillvärme, kan produktionskostnaderna vara lägre än då konventionella energikällor används. Den potentiella inkomsten från produktionen estimeras till 673 790 SEK/year med en inköpskostnad om 93 861 SEK samt årliga omkostnader om 14 080 SEK/year.
9

Waste Heat Driven Membrane Distillation Integrated with Stirling Engine

Bergman Larsson, Niklas, Talåsen, Jonatan January 2022 (has links)
See file / Se bif. fil

Page generated in 0.0411 seconds