Chemically induced phosphorescence from manganese(II) during the oxidation of various compounds by manganese(III), (IV) break and (VII) in acidic aqueous solutions

Chemiluminescence was observed during the manganese(III), (IV) and (VII) oxidations of sodium tetrahydroborate, sodium dithionite, sodium sulfite and hydrazine sulfate in acidic aqueous solution. From the corrected chemiluminescence spectra, the wavelengths of maximum emission were 689±5 and 734±5 nm when the reactions were performed in sodium hexametaphosphate and sodium dihydrogenorthophosphate/ orthophosphoric acid environments, respectively. The corrected phosphorescence spectrum of manganese(II) sulfate in a solution of sodium hexametaphosphate at 77 K exhibited two peaks with maxima at 688 and 730 nm. The chemical and spectroscopic evidence presented strongly supported the postulation that the emission was an example of solution-phase chemically induced phosphorescence of manganese(II) thereby, confirming earlier predictions that the chemiluminescence from acidic potassium permanganate reactions originated from an excited manganese(II) species.

Characterisation of a synthesised fluorescent ligand (4-acridinol-1-sulphonic acid) using nuclear magnetic resonance spectroscopy

The synthesis and complete characterisation of the fluorescent ligand, 4-acridinol-1-sulphonic acid (the acridine analogue of 8-quinolinol-5-sulfonic acid) is described. Using a judicious array of nuclear magnetic resonance spectroscopy experiments, the structural elucidation and full assignment of all proton and carbon chemical shifts were afforded. The 4-acridinol-1-sulphonic acid was found to behave in a similar manner to 8-quinolinol-5-sulphonic acid, forming fluorescent complexes with magnesium(II) and zinc(II). The uncorrected emission maxima for the metal–acridinol complexes were found to be at around 620 nm compared to 505 nm for the respective quinolinol complexes. Unfortunately, preliminary spectrofluorimetric analytical figures of merit revealed that the detection limits of the new acridinol metal complexes were one and a half orders of magnitude poorer than those attained with the corresponding quinolinol ligand. However, in contrast to 8-quinolinol-5-sulphonic acid, the 4-acridinol-1-sulphonic acid ligand showed considerable selectivity for magnesium(II) and zinc(II) over aluminium(III).

A new method for locating the global optimum : application of the cutting angle method to molecular structure prediction

Many problems in chemistry depend on the ability to identify the global minimum or maximum of a function. Examples include applications in chemometrics, optimization of reaction or operating conditions, and non-linear least-squares analysis. This paper presents the results of the application of a new method of deterministic global optimization, called the cutting angle method (CAM), as applied to the prediction of molecular geometries. CAM is shown to be competitive with other global optimization techniques for several benchmark molecular conformation problem. CAM is a general method that can also be applied to other computational problems involving global minima, global maxima or finding the roots of nonlinear equations.

A multi-wavelet based technique for calculating dense 2D disparity maps from stereo

A vision based approach for calculating accurate 3D models of the objects is presented. Generally industrial visual inspection systems capable of accurate 3D depth estimation rely on extra hardware tools like laser scanners or light pattern projectors. These tools improve the accuracy of depth estimation but also make the vision system costly and cumbersome. In the proposed algorithm, depth and dimensional accuracy of the produced 3D depth model depends on the existing reference model instead of the information from extra hardware tools. The proposed algorithm is a simple and cost effective software based approach to achieve accurate 3D depth estimation with minimal hardware involvement. The matching process uses the well-known coarse to fine strategy, involving the calculation of matching points at the coarsest level with consequent refinement up to the finest level. Vector coefficients of the wavelet transform-modulus are used as matching features, where wavelet transform-modulus maxima defines the shift invariant high-level features with phase pointing to the normal of the feature surface. The technique addresses the estimation of optimal corresponding points and the corresponding 2D disparity maps leading to the creation of accurate depth perception model.

Depth estimation using multi-wavelet analysis based stereo vision approach

The problem of dimensional defects in aluminum die- casting is widespread throughout the foundry industry and their detection is of paramount importance in maintaining product quality. Due to the unpredictable factory environment and metallic, with highly reflective, nature of aluminum die-castings, it is extremely hard to estimate true dimensionality of the die-casting, autonomously. In this work, we propose a novel robust 3D reconstruction algorithm capable of reconstructing dimensionally accurate 3D depth models of the aluminum die-castings. The developed system is very simple and cost effective as it consists of only a stereo cameras pair and a simple fluorescent light. The developed system is capable of estimating surface depths within the tolerance of 1.5 mm. Moreover, the system is invariant to illuminative variations and orientation of the objects in the input image space, which makes the developed system highly robust. Due to its hardware simplicity and robustness, it can be implemented in different factory environments without a significant change in the setup.

Stereo correspondence estimation using multiwavelets scale-space representation-based multiresolution analysis

A multiresolution technique based on multiwavelets scale-space representation for stereo correspondence estimation is presented. The technique uses the well-known coarse-to-fine strategy, involving the calculation of stereo correspondences at the coarsest resolution level with consequent refinement up to the finest level. Vector coefficients of the multiwavelets transform modulus are used as corresponding features, where modulus maxima defines the shift invariant high-level features (multiscale edges) with phase pointing to the normal of the feature surface. The technique addresses the estimation of optimal corresponding points and the corresponding 2D disparity maps. Illuminative variation that can exist between the perspective views of the same scene is controlled using scale normalization at each decomposition level by dividing the details space coefficients with approximation space. The problems of ambiguity, explicitly, and occlusion, implicitly, are addressed by using a geometric topological refinement procedure. Geometric refinement is based on a symbolic tagging procedure introduced to keep only the most consistent matches in consideration. Symbolic tagging is performed based on probability of occurrence and multiple thresholds. The whole procedure is constrained by the uniqueness and continuity of the corresponding stereo features. The comparative performance of the proposed algorithm with eight famous existing algorithms, presented in the literature, is shown to validate the claims of promising performance of the proposed algorithm.

Depth estimation of metallic objects using multiwavelets scale-space representation

The problem of dimensional defects in aluminum die-castings is widespread throughout the foundry industry and their detection is of paramount importance in maintaining product quality. Due to the unpredictable factory environment and metallic with highly reflective nature, it is extremely hard to estimate true dimensionality of these metallic parts, autonomously. Some existing vision systems are capable of estimating depth to high accuracy, however are very much hardware dependent, involving the use of light and laser pattern projectors, integrated into vision systems or laser scanners. However, due to the reflective nature of these metallic parts and variable factory environments, the aforementioned vision systems tend to exhibit unpromising performance. Moreover, hardware dependency makes these systems cumbersome and costly. In this work, we propose a novel robust 3D reconstruction algorithm capable of reconstructing dimensionally accurate 3D depth models of the aluminum die-castings. The developed system is very simple and cost effective as it consists of only a pair of stereo cameras and a defused fluorescent light. The proposed vision system is capable of estimating surface depths within the accuracy of 0.5mm. In addition, the system is invariant to illuminative variations as well as orientation and location of the objects on the input image space, making the developed system highly robust. Due to its hardware simplicity and robustness, it can be implemented in different factory environments without a significant change in the setup. The proposed system is a major part of quality inspection system for the automotive manufacturing industry.

Depth estimation using multiwavelet analysis based stereo vision approach

The problem of dimensional defects in aluminum die-casting is widespread throughout the foundry industry and their detection is of paramount importance in maintaining product quality. Due to the unpredictable factory environment and metallic, with highly reflective, nature of aluminum die-castings, it is extremely hard to estimate true dimensionality of the die-casting, autonomously. In this work, we propose a novel robust 3D reconstruction algorithm capable of reconstructing dimensionally accurate 3D depth models of the aluminum die-castings. The developed system is very simple and cost effective as it consists of only a stereo camera pair and a simple fluorescent light. The developed system is capable of estimating surface depths within the tolerance of 1.5 mm. Moreover, the system is invariant to illuminative variations and orientation of the objects in the input image space, which makes the developed system highly robust. Due to its hardware simplicity and robustness, it can be implemented in different factory environments without a significant change in the setup.

The effect of hydrogenation on the ECAP compaction of Ti–6Al–4V powder and the mechanical properties of compacts

The effect of hydrogen content on the compaction of Ti–6Al–4V powder at low temperatures, namely 500 °C, using equal channel angular pressing (ECAP) with back pressure has been investigated. The properties of the compacts before and after a heat treatment and de-hydrogenation cycle have been determined. Compaction of powder by ECAP (500 °C and 260 MPa) has shown maximum levels of relative density of 99.3% and 99.4% when charged with 0.05–0.1 wt.% and 0.61–0.85 wt.% of hydrogen, respectively. After the de-hydrogenation heat treatment the diffusion bonding between individual powder particles was completed and the microstructure was altered, depending on the level of hydrogen content. Two local maxima of 99.2% and 98.1% were observed in the measured density of consolidated compacts for hydrogen contents between 0.05 wt.% and 0.1 wt.% and between 0.61 wt.% and 0.85 wt.%, respectively. However, the mechanical properties of the compacts within these two ranges of hydrogen content were significantly different due to a difference in the observed microstructure. An exceptionally high ductility of 29%, in combination with a relatively high strength of ~560 MPa, was measured in a shear punch test on specimens which had a prior hydrogen level of 0.05 wt.% before the heat treatment. It was shown that material consolidated from powder hydrogenated to low levels of hydrogen before compaction has the potential to offer substantial improvements in mechanical properties after a suitable heat treatment.

Chemistry, spectroscopy and analytical applications of certain chemiluminescent reactions

Chemiluminescence, the production of light from a chemical reaction, has found widespread use in analytical chemistry. Both tris (2, 2’-bipyridyl) ruthenium (II) and acidic potassium permanganate are chemiluminescence reagents that have been employed for the determination of a diverse range of analytes. This thesis encompasses some fundamental investigations into the chemistry and spectroscopy of these chemiluminescence reactions as well as extending the scope of their analytical applications. Specifically, a simple and robust capillary electrophoresis chemiluminescence detection system for the determination of codeine, O6-methylcodeine and thebaine is described, based upon the reaction of these analytes with chemically generated tris(2,2'-bipyridyl)ruthenium(III) prepared in sulfuric acid (0.05 M). The reagent solution was contained in a glass detection cell, which also held both the capillary and the cathode. The resultant chemiluminescence was monitored directly using a photomultiplier tube mounted flush against the base of the detection cell. The methodology, which incorporated a field amplification sample introduction procedure, realised detection limits (3a baseline noise) of 5 x 10~8 M for both codeine and O6-methylcodeine and 1 x 10~7 M for thebaine. The relative standard deviations of the migration times and the peak areas for the three analytes ranged from 2.2 % up to 2.5 % and 1.9 % up to 4.6 % respectively. Following minor instrumental modifications, morphine, oripavine and pseudomorphine were determined based upon their reaction with acidic potassium permanganate in the presence of sodium polyphosphate. To ensure no migration of the permanganate anion occurred, the anode was placed at the detector end whilst the electroosmotic flow was reversed by the addition of hexadimethrine bromide (0.001% m/v) to the electrolyte. The three analytes were separated counter to the electroosmotic flow via their interaction with a-cyclodextrin. The methodology realised detection limits (3 x S/N) of 2.5 x 10~7 M for both morphine and oripavine and 5 x 10~7 M for pseudomorphine. The relative standard deviations of the migration times and the peak heights for the three analytes ranged from 0.6 % up to 0.8 % and 1.5% up to 2.1 % respectively. Further improvements were made by incorporating a co-axial sheath flow detection cell. The methodology was validated by comparing the results realised using this technique with those obtained by high performance liquid chromatography (HPLC), for the determination of both morphine and oripavine in seven industrial process liquors. A complimentary capillary electrophoresis procedure with UV-absorption detection was also developed and applied to the determination of morphine, codeine, oripavine and thebaine in nine process liquors. The results were compared with those achieved using a standard HPLC method. Although over eighty papers have appeared in the literature on the analytical applications of acidic potassium permanganate chemiluminescence, little effort has been directed towards identifying the origin of the luminescence. It was found that chemiluminescence was generated during the manganese(III), manganese(IV) and manganese(VII) oxidations of sodium borohydride, sodium dithionite, sodium sulfite and hydrazine sulfate in acidic aqueous solution. From the corrected chemiluminescence spectra, the wavelengths of maximum emission were 689 ± 5 nm and 734 ± 5 nm when the reactions were performed in sodium hexametaphosphate and sodium dihydrogenorthophosphate or orthophosphoric acid environments respectively. The corrected phosphorescence spectrum of manganese(II) sulfate in a solution of sodium hexametaphosphate at 77 K, exhibited two peaks with maxima at 688 nm and 730 nm. The chemical and spectroscopic evidence presented strongly supported the postulation that the emission was an example of solution phase chemically induced phosphorescence of manganese(II). Thereby confirming earlier predictions that the chemiluminescence from acidic potassium permanganate reactions originated from an excited manganese(II) species. Additionally, these findings have had direct analytical application in that manganese(IV) was evaluated as a new reagent for chemiluminescence detection. The oxidations of twenty five organic and inorganic species, with solublised manganese(IV), were found to elicit analytically useful chemiluminescence with detection limits (3 x S/N) for Mn(II), Fe(II), morphine and codeine of 5 x 10-8 M, 2.5 x 10-7 M, 7.5 x 10-8 M and 5 x 10-8M, respectively. The corrected emission spectra from four different analytes gave wavelengths of maximum emission in the range from 733 nm up to 740 nm indicating that these chemiluminescence reactions also shared a common emitting species, excited manganese(II). Whilst several analytical problems were addressed in this thesis and answers to certain questions regarding the fundamentals of acidic potassium permanganate chemiluminescence were proposed, there are several areas that would benefit from further research. These are outlined in the final chapter of this thesis.

Stereo image matching using wavelet scale-space representation

A multi-resolution technique for matching a stereo pair of images based on translation invariant discrete multi-wavelet transform is presented. The technique uses the well known coarse to fine strategy, involving the calculation of matching points at the coarsest level with consequent refinement up to the finest level. Vector coefficients of the wavelet transform modulus are used as matching features, where modulus maxima defines the shift invariant high-level features (multiscale edges) with phase pointing to the normal of the feature surface. The technique addresses the estimation of optimal corresponding points and the corresponding 2D disparity maps. Illuminative variation that can exist between the perspective views of the same scene is controlled using scale normalization at each decomposition level by dividing the details space coefficients with approximation space and then using normalized correlation. The problem of ambiguity, explicitly, and occlusion, implicitly, is addressed by using a geometric topological refinement procedure and symbolic tagging.

Birth of a biome : insights into the assembly and maintenance of the Australian arid zone biota

The integration of phylogenetics, phylogeography and palaeoenvironmental studies is providing major insights into the historical forces that have shaped the Earth’s biomes. Yet our present view is biased towards arctic and temperate/tropical forest regions, with very little focus on the extensive arid regions of the planet. The Australian arid zone is one of the largest desert landform systems in the world, with a unique, diverse and relatively well-studied biota. With foci on palaeoenvironmental and molecular data, we here review what is known about the assembly and maintenance of this biome in the context of its physical history, and in comparison with other mesic biomes. Aridification of Australia began in the Mid-Miocene, around 15 million years, but fully arid landforms in central Australia appeared much later, around 1–4 million years. Dated molecular phylogenies of diverse taxa show the deepest divergences of arid-adapted taxa from the Mid-Miocene, consistent with the onset of desiccation. There is evidence of arid-adapted taxa evolving from mesicadapted ancestors, and also of speciation within the arid zone. There is no evidence for an increase in speciation rate during the Pleistocene, and most arid-zone species lineages date to the Pliocene or earlier. The last 0.8 million years have seen major fluctuations of the arid zone, with large areas covered by mobile sand dunes during glacial maxima. Some large, vagile taxa show patterns of recent expansion and migration throughout the arid zone, in parallel with the ice sheet-imposed range shifts in Northern Hemisphere taxa. Yet other taxa show high lineage diversity and strong phylogeographical structure, indicating persistence in multiple localised refugia over several glacial maxima. Similar to the Northern Hemisphere, Pleistocene range shifts have produced suture zones, creating the opportunity for diversification and speciation through hybridisation, polyploidy and parthenogenesis. This review highlights the opportunities that development of arid conditions provides for rapid and diverse evolutionary radiations, and re-enforces the emerging view that Pleistocene environmental change can have diverse impacts on genetic structure and diversity in different biomes. There is a clear need for more detailed and targeted phylogeographical studies of Australia’s arid biota and we suggest a framework and a set of a priori hypotheses by which to proceed.

Wavelets/multiwavelets bases and correspondence estimation problem : an analytic study

Correspondence estimation in one of the most active research areas in the field of computer vision and number of techniques has been proposed, possessing both advantages and shortcomings. Among the techniques reported, multiresolution analysis based stereo correspondence estimation has gained lot of research focus in recent years. Although, the most widely employed medium for multiresolution analysis is wavelets and multiwavelets bases, however, relatively little work has been reported in this context. In this work we have tried to address some of the issues regarding the work done in this domain and the inherited shortcomings. In the light of these shortcomings, we propose a new technique to overcome some of the flaws that could have significantly impact on the algorithm performance and has not been addressed in the earlier propositions. Proposed algorithm uses multiresolution analysis enforced with wavelets/multiwavelts transform modulus maxima to establish correspondences between the stereo pair of images. Variety of wavelets and multiwavelets bases, possessing distinct properties such as orthogonality, approximation order, short support and shape are employed to analyse their effect on the performance of correspondence estimation. The idea is to provide knowledge base to understand and establish relationships between wavelets and multiwavelets properties and their effect on the quality of stereo correspondence estimation.

Inexplicable inefficiency of avian molt? Insights from an opportunistically breeding arid-zone species, Lichenostomus penicillatus

The majority of bird species studied to date have molt schedules that are not concurrent with other energy demanding life history stages, an outcome assumed to arise from energetic trade-offs. Empirical studies reveal that molt is one of the most energetically demanding and perplexingly inefficient growth processes measured. Furthermore, small birds, which have the highest mass-specific basal metabolic rates (BMR_m), have the highest costs of molt per gram of feathers produced. However, many small passerines, including white-plumed honeyeaters (WPHE; Lichenostomus penicillatus), breed in response to resource availability at any time of year, and do so without interrupting their annual molt. We examined the energetic cost of molt in WPHE by quantifying weekly changes in minimum resting metabolic rate (RMR_min) during a natural-molt period in 7 wild-caught birds. We also measured the energetic cost of feather replacement in a second group of WPHEs that we forced to replace an additional 25% of their plumage at the start of their natural molt period. Energy expenditure during natural molt revealed an energy conversion efficiency of just 6.9% (±0.57) close to values reported for similar-sized birds from more predictable north-temperate environments. Maximum increases in RMR_min during the molt of WPHE, at 82% (±5.59) above individual pre-molt levels, were some of the highest yet reported. Yet RMR_min maxima during molt were not coincident with the peak period of feather replacement in naturally molting or plucked birds. Given the tight relationship between molt efficiency and mass-specific metabolic rate in all species studied to date, regardless of life-history pattern (Efficiency (%) = 35.720•10^-0.494BMRm; r² = 0.944; p =<0.0001), there appears to be concomitant physiological costs entrained in the molt period that is not directly due to feather replacement. Despite these high total expenditures, the protracted molt period of WPHE significantly reduces these added costs on a daily basis.