Dissertations / Theses on the topic 'Vibrational analysis'
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1
Mahdi, Hassan Hamoodi. "Vibrational modal analysis of rotating machines." Thesis, University of Hertfordshire, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303391.
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James, Philippe Pierre. "A technique for the assessment of strength of coupling between statistical energy analysis subsystems." Thesis, University of Southampton, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.245304.
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Lavalle, Juan Carlos. "Failure detection in transformers using vibrational analysis." Thesis, Massachusetts Institute of Technology, 1986. http://hdl.handle.net/1721.1/106705.
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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1986.MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING
Bibliography: leaves 191-194.
by Juan Carlos Lavalle.
M.S.
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Hirai, Kazuo. "Time-energy analysis of molecular vibrational spectra /." Thesis, Connect to this title online; UW restricted, 1997. http://hdl.handle.net/1773/8518.
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Dosche, Carsten, Michael U. Kumke, F. Ariese, A. N. Bader, C. Gooijer, P. I. Dosa, S. Han, et al. "Shpol’skii spectroscopy and vibrational analysis of [N]phenylenes." Universität Potsdam, 2003. http://opus.kobv.de/ubp/volltexte/2007/1307/.
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Vibrationally resolved fluorescence spectra of four angular [N]phenylenes were recorded with laser excited Shpol’skii spectroscopy (LESS) in an n-octane matrix at 10 K. In general, the same vibrational frequencies were observed in the fluorescence excitation and emission spectra, indicating that the geometries of ground and electronically excited state are very similar. Because of intensity borrowing from the S2 state, vibrations of two different symmetries were observed in the fluorescence excitation spectra of angular [3]phenylene and zig-zag[5]phenylene. This finding allowed the location of the S2 state for these compounds. DFT calculations(RB3LYP/6-31G*) of the ground state vibrational frequencies were made. The calculated vibrational modes were in reasonably good agreement with the experimental data. A new very low-frequency vibration of
approximately 100 cm-1 was predicted and experimentally confirmed for all [N]phenylenes investigated. This vibration seems to be unique for [N]phenylenes and is attributed to an in-plane movement of the carbon backbone.
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Farhat, Ali Y. "Vibrational analysis of composite double layer skeletal structures." Thesis, University of Surrey, 1992. http://epubs.surrey.ac.uk/624/.
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Tahmasian, Sevak. "Design, Analysis, and Optimization of Vibrational Control Strategies." Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/52564.
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This dissertation presents novel vibrational control strategies for mechanical control-affine systems with high-frequency, high-amplitude inputs. Since these control systems use high-frequency, zero-mean, periodic inputs, averaging techniques are widely used in the analysis of their dynamics. By studying their time-averaged approximations, new properties of the averaged dynamics of this class of systems are revealed. Using these properties, the problem of input optimization of vibrational control systems was formulated and solved by transforming the problem to a constrained optimization one.
Geometric control theory provides powerful tools for studying the control properties of control-affine systems. Using the concepts of vibrational and geometric controls and averaging tools, a closed-loop control strategy for trajectory tracking of a class of underactuated mechanical control-affine systems is developed. In the developed control law, the fact that for underactuated systems, the actuated coordinates together with the corresponding generalized velocities can be considered as generalized inputs for the unactuated dynamics plays the main role. Using the developed control method, both actuated and unactuated coordinates of the system are able to follow slowly time-varying prescribed trajectories on average. The developed control method is applied for altitude control of flapping wing micro-air vehicles by considering the sweeping (flapping) angle of the wings as the inputs. Using the feathering (pitch) angles of the wings as additional inputs, and using non-symmetric flapping, the control method is then extended for three-dimensional flight control of flapping wing micro-air vehicles.Ph. D.
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Wood, Michael G. "Damage analysis of bridge structures using vibrational techniques." Thesis, Aston University, 1992. http://publications.aston.ac.uk/11832/.
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Much research is currently centred on the detection of damage in structures using vibrational data. The work presented here examined several areas of interest in support of a practical technique for identifying and locating damage within bridge structures using apparent changes in their vibrational response to known excitation. The proposed goals of such a technique included the need for the measurement system to be operated on site by a minimum number of staff and that the procedure should be as non-invasive to the bridge traffic-flow as possible. Initially the research investigated changes in the vibrational bending characteristics of two series of large-scale model bridge-beams in the laboratory and these included ordinary-reinforced and post-tensioned, prestressed designs. Each beam was progressively damaged at predetermined positions and its vibrational response to impact excitation was analysed. For the load-regime utilised the results suggested that the infuced damage manifested itself as a function of the span of a beam rather than a localised area. A power-law relating apparent damage with the applied loading and prestress levels was then proposed, together with a qualitative vibrational measure of structural damage. In parallel with the laboratory experiments a series of tests were undertaken at the sites of a number of highway bridges. The bridges selected had differing types of construction and geometric design including composite-concrete, concrete slab-and-beam, concrete-slab with supporting steel-troughing constructions together with regular-rectangular, skewed and heavily-skewed geometries. Initial investigations were made of the feasibility and reliability of various methods of structure excitation including traffic and impulse methods. It was found that localised impact using a sledge-hammer was ideal for the purposes of this work and that a cartridge `bolt-gun' could be used in some specific cases.
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Ding, Xinli. "Generalized critical points analysis of acetylene vibrational dynamics /." view abstract or download file of text, 2004. http://wwwlib.umi.com/cr/uoregon/fullcit?p3120621.
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Thesis (Ph. D.)--University of Oregon, 2004.Typescript. Includes vita and abstract. Includes bibliographical references (leaves 145-154). Also available for download via the World Wide Web; free to University of Oregon users.
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Briscoe, Anthony Roy. "Asymmetric vibrational power transmission in fluid filled pipes." Thesis, University of Southampton, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.241147.
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Ito, Hironobu. "Analysis of nonlinear vibrational spectroscopies using molecular dynamics simulation." 京都大学 (Kyoto University), 2017. http://hdl.handle.net/2433/225415.
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Zare, Abdolreza. "Exact vibrational analysis of prismatic plate and sandwich structures." Thesis, Cardiff University, 2004. http://orca.cf.ac.uk/55938/.
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Transcendental stiffness matrices for vibration (or buckling) analysis have long been available for a range of structural members. Such stiffness matrices are exact in the sense that they are obtained from an analytical solution of the governing differential equations of the member. Hence, assembly of the member stiffnesses to obtain the overall stiffness matrix of the structure results in a transcendental eigenproblem that yields exact solutions and which can be solved with certainty using the Wittrick-Williams algorithm. Convergence is commonly achieved by bisection, despite the fact that the method is known to be relatively slow. Quicker methods are available, but their implementation is hampered by the highly volatile nature of the determinant of the structure's transcendental stiffness matrix, particularly in the vicinity of the poles, which may or may not correspond to eigenvalues. However, when the exact solution exists, the member has a recently discovered property that can also be expressed analytically and is called its member stiffness determinant. The member stiffness determinant is a property of the member when fully clamped boundary conditions are imposed upon it. It is then defined as the determinant of the member stiffness matrix when the member is sub-divided into an infinite number of identical sub-members. Each sub-member is therefore of infinitely small length so that its clamped-ended natural frequencies are infinitely large. Hence the contribution from the member stiffness matrix to the Jq count of the W-W algorithm will be zero. In general, the member stiffness determinant is normalised by dividing by its value when the eigenparameter (i.e. the frequency or buckling load factor) is zero, as otherwise it would become infinite. Part A of this thesis develops the first two applications of member stiffness determinants to the calculation of natural frequencies or elastic buckling loads of prismatic assemblies of isotropic and orthotopic plates subject to in-plane axial and transverse loads. A major advantage of the member stiffness determinant is that, when its values for all members of a structure are multiplied together and are also multiplied by the determinant of the transcendental overall stiffness matrix of the structure, the result is a determinant which has no poles and is substantially less volatile when plotted against the eigenparameter. Such plots provide a significantly better platform for the development of efficient, computer-based routines for convergence on eigenvalues by curve prediction techniques. On the other hand, Part B presents the development of exact dynamic stiffness matrices for three models of sandwich beams. The simplest one is only able to model the flexural vibration of asymmetric sandwich beams. Extending the first model to include axial and rotary inertia makes it possible to predict the axial and shear thickness modes of vibration in addition to those corresponding to flexure. This process culminates in a unique model for a three layer Timoshenko beam. The crucial difference of including axial inertia in the second model, enables the resulting member dynamic stiffness matrix (exact finite element) to be included in a general model of two dimensional structures for the first time. Although the developed element is straight, it can also be used to model curved structures by using an appropriate number of straight elements to model the geometry of the curve. Finally, it has been shown that considering a homogeneous deep beam as an equivalent three-layer beam allows the beam to have additional shear modes, besides the flexural, axial and fundamental shear thickness modes. Also for every combination of layer thickness, the frequencies of the three-layer beam are less than the corresponding frequencies calculated for the equivalent beam model with only one layer, since it is equivalent to providing additional flexibility to the system. However, a suitable combination of layer thicknesses for any mode may be found that yields the minimum frequency. It is anticipated that these frequencies would probably be generated by a single layer model of the homogeneous beam if at least a third order shear deformation theory was incorporated. Numerous examples have been given to validate the theories and to indicate their range of application. The results presented in these examples are identical to those that are available from alternative exact theories and otherwise show good correlation with a selection of comparable approximate results that are available in the literature. In the latter case, the differences in the results are attributable to many factors that vary widely from different solution techniques to differences in basic assumptions.
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Wei, Shijun. "Trace Analysis of Crystalline Silica Aerosol Using Vibrational Spectroscopy." University of Cincinnati / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1595849455064302.
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Newman, N. D. "The application of parallel processing methods to vibrational analysis." Thesis, Aston University, 1996. http://publications.aston.ac.uk/15363/.
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The trend in modal extraction algorithms is to use all the available frequency response functions data to obtain a global estimate of the natural frequencies, damping ratio and mode shapes. Improvements in transducer and signal processing technology allow the simultaneous measurement of many hundreds of channels of response data. The quantity of data available and the complexity of the extraction algorithms make considerable demands on the available computer power and require a powerful computer or dedicated workstation to perform satisfactorily. An alternative to waiting for faster sequential processors is to implement the algorithm in parallel, for example on a network of Transputers. Parallel architectures are a cost effective means of increasing computational power, and a larger number of response channels would simply require more processors. This thesis considers how two typical modal extraction algorithms, the Rational Fraction Polynomial method and the Ibrahim Time Domain method, may be implemented on a network of transputers. The Rational Fraction Polynomial Method is a well known and robust frequency domain 'curve fitting' algorithm. The Ibrahim Time Domain method is an efficient algorithm that 'curve fits' in the time domain. This thesis reviews the algorithms, considers the problems involved in a parallel implementation, and shows how they were implemented on a real Transputer network.
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Gardner, P. "Vibrational spectroscopic studies of absorbed species on metal surfaces." Thesis, University of East Anglia, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382867.
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Panayiotou, Helen. "Vibrational spectroscopy of human hair keratin fibres." Thesis, Queensland University of Technology, 1998. https://eprints.qut.edu.au/36946/1/36946_Panayiotou_1998.pdf.
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This thesis is concerned with an investigation of human hair fibres, and is primarily directed towards forensic and cosmetic applications. Initially, a small study was conducted by the use of scanning electron microscopy in order to obtain a visual understanding of the human hair fibre. However, the main focus of the thesis is on the application of vibrational spectroscopy techniques for the investigation of single hair fibres (for forensic studies) or their bulk samples (for cosmetic studies).
Previous research directed towards the forensic field, failed to discriminate human hair fibres with the aid of FT-IR microspectroscopy. In the present study, the same technique was again utilised but the spectral data was interpreted by chemometrics. A number of different hypotheses were proposed and tested. Initially, it was concluded that the best sampling site is the middle section of a single hair fibre. It has been shown that the variation between hair fibres from two individual sources exceeds that of several hair fibres from the same source. In general, it was concluded that human, single, hair fibres can be discriminated on the basis of gender, race and treatment (single treatments and multiple treatments). Samples with known history were used to build a reference set, and blind samples were used for validation. Overall, a success rate of about 83% was achieved. From the present results, it is concluded that FT-IR micospectroscopy followed by chemometrics is a powerful technique for the discrimination of human hair single fibres. For the cosmetic studies, FT-Raman and FT-IR/PAS, were used as complementary techniques to investigate the oxidation of hair fibres by varying the treatment times for permanently dyed hair. FT-Raman was used to study the oxidation of the S-S band, while FT-IR/PAS was employed to study the S=O oxidation states. The spectra were interpreted by the use of chemometrics. Overall, the results observed for the FT-Raman study were similar to those observed in the FT-IR/PAS. Curve fitting analysis, indicated that approximately 11 % of the disulfide bonds remain broken, while the rest are reformed. In addition, the ratio between the cystine to cysteic acid being formed, is 1.8. These observations agree with comments in the literature.
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Wang, Yaolun. "Vibrational measurement techniques applied on FE-model updating." Thesis, Linnéuniversitetet, Institutionen för maskinteknik (MT), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-45213.
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In this thesis, the dynamics of two plates overlapping and connected by three bolts are studied. The data collected in the test are used in modal analysis. The vibrational test and the modal analysis were made using an LMS system. Hammer excitation is used for the tests. The main purpose of this thesis is to study how the suspensions affect the extracted eigenfrequencies and modal dampings. In this thesis, more than 10 suspensions were examined. Another objective in this thesis work is to build an FE-model. This model is made using the software Abaqus. To improve the reliability of the FE-model, a set of reliable experimental data is used to calibrate the model. The calibrated FE-model, using the measurement data, has a dynamic behavior close to the measurement data.
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Baker, J. R. "The measurement of vibrational power transmission using laser technology." Thesis, University of Southampton, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.358950.
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Krantz, Dino. "Methodology and vibrational analysis for measurements on a VTOL RAPS." Thesis, Linköpings universitet, Fluida och mekatroniska system, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-142928.
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In this thesis a methodology for measuring vibrations has been produced andinvestigated for APID 60, a rotorcraft in a Vertical Take-off and landing remotelypiloted aircraft system (VTOL RPAS). A comparative study was carried out forthe purpose of identifying the methodology with respect to design modificationscommon to the APID 60. The pilot-study identified experimental modal analysis(EMA) as a feasible part of the methodology for experimentally extracting themodal parameters of a structure. The EMA was performed on the main frameof the APID 60 where an impact hammer test was chosen as the technique forextracting the response data. As a comparison a point mass was added to thestructure to alter the dynamic properties and the test was repeated.The results from the EMA was compared with a modal analysis performednumerically with a calculation software. Comparison of the results from EMAwith the modal analysis performed numerically indicates consistency. This confirmsa good reliability of the methodology produced. However, the structure onwhich the test were preformed is simple in terms of constant structural properties.Further work should therefore investigate whether this methodology of measuringvibrations could be successfully applied to a structure with higher complexity.
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Gallant, Bryan M. "Vibrational analysis of a shipboard free electron laser beam path." Monterey, California. Naval Postgraduate School, 2011. http://hdl.handle.net/10945/10607.
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This thesis explores the deployment of a free electron laser (FEL) weapon system in a shipboard vibration environment. A concept solid model of a shipboard FEL is developed and used as a basis for a finite element model which is subjected to vibration simulation in MATLAB. Vibration input is obtained from ship shock trials data and wave excited motion data from ship motion simulation software. Emphasis is placed on the motion of electron beam path components of the FEL and the feasibility of operation aboard ship. The resulting component motion after passive isolation control is within the amplitudes and frequencies that will allow at sea FEL operation with active electron beam steering.
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Llewelyn, Elizabeth Sara. "Novel methods in the analysis of polymers using vibrational spectroscopy." Thesis, University of Southampton, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.241948.
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Kennedy, I. "Vibration transmissibility characteristics of fibre and steel reinforced flexible pipes." Thesis, University of Manchester, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.378334.
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Carter, Elizabeth Anne. "Vibrational spectroscopic studies of wool." Thesis, Queensland University of Technology, 1997.
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Fourier transfonn (FT) Raman, Raman microspectroscopy and Fourier transform infrared (FTIR) spectroscopy have been used for the structural analysis and characterisation of
untreated and chemically treated wool fibres. For FT -Raman spectroscopy novel methods of sample presentation have been developed and optimised for the analysis of wool. No significant fluorescence was observed and the
spectra could be obtained routinely. The stability of wool keratin to the laser source was investigated and the visual and spectroscopic signs of sample damage were established.
Wool keratin was found to be extremely robust with no signs of sample degradation observed for laser powers of up to 600 m W and for exposure times of up to seven and half hours. Due to improvements in band resolution and signal-to-noise ratio, several previously unobserved spectral features have become apparent. The assignment of the
Raman active vibrational modes of wool have been reviewed and updated to include these features. The infrared spectroscopic techniques of attenuated total reflectance (ATR) and photoacoustic (P A) have been used to examine shrinkproofed and mothproofed wool samples. Shrinkproofing is an oxidative chemical treatment used to selectively modifY the surface of a wool fibre. Mothproofing is a chemical treatment applied to wool for the
prevention of insect attack. The ability of PAS and A TR to vary the penetration depth by varying certain instrumental parameters was used to obtain spectra of the near surface
regions of these chemically treated samples. These spectra were compared with those taken with a greater penetration depth, which therefore represent more of the bulk wool
sample. The PA and ATR spectra demonstrated that oxidation was restricted to the near-surface layer of wool. Extensive curve fitting of ATR spectra of untreated wool
indicated that cuticle was composed of a mixed protein conformation, but was predominately that of an a.-helix. The cortex was proposed to be a mixture of both a.helical
and ~-pleated sheet protein conformations. These findings were supported by PAS depth profiling results. Raman microspectroscopy was used in an extensive investigation of the molecular structure of the wool fibre. This included determining the orientation of certain functional
groups within the wool fibre and the symmetry of particular vibrations. The orientation ofbonds within the wool fibre was investigated by orientating the wool fibre axis parallel
and then perpendicular to the plane of polarisation of the electric vector of the incident radiation. It was experimentally determined that the majority of C=O and N-H bonds of the peptide bond of wool lie parallel to the fibre axis. Additionally, a number of the important vibrations associated with the a-helix were also found to lie parallel to the fibre axis. Further investigation into the molecular structure of wool involved determining what effect stretching the wool fibre had on bond orientation. Raman spectra of stretched and unstretched wool fibres indicated that extension altered the orientation ofthe aromatic
rings, the CH2 and CH3 groups of the amino acids. Curve fitting results revealed that extension resulted in significant destruction of the a-helix structure a substantial increase in the P-pleated sheet structure. Finally, depolarisation ratios were calculated for Raman
spectra. The vibrations associated with the aromatic rings of amino acids had very low ratios which indicated that the vibrations were highly symmetrical.
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Tamer, Aykut. "Analysis And Design Of Helicopter Rotor Blades For Reduced Vibrational Level." Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613661/index.pdf.
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In this thesis analysis and design of helicopter rotor blades were discussed for reduced
vibrational level. For this purpose an optimization procedure was developed which involves
coupling of the comprehensive rotorcraft analysis tool CAMRAD JA and the gradient based
optimization algorithm. The main goal was to achieve favorable blade structural dynamics
characteristics that would lead to reduction in vibrational level. For this purpose blade
stiffness and mass distributions were considered as the design variables. In order to avoid
likely occurrences of unrealistic results, the analyses were subjected to constraints which
were sensitive to the design variables. The optimization procedure was applied on two
isolated rotor blades and a full helicopter with main rotor, tail rotor and fuselage by using
natural frequency separation and hub load minimization respectively. While the former
approach relied on the blade natural frequencies, the latter approach involved higher
harmonic aerodynamic and blade motion calculations. For both approaches, the
improvement in vibration characteristics and blade mass and stiffness distributions of the
initial design and the design after optimization analyses were compared and discussed.
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Medvid, Sophia V. "Analysis of The Vibrational Modes of a Brass Plate and Mellophone." Ohio University Honors Tutorial College / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ouhonors1587991088883357.
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Atter, Glenn David. "The study and refinement of vibrational force fields using optical and inelastic neutron scattering spectra." Thesis, University of York, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.319456.
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Watkins, Gareth Mostyn. "Ligand isotope vibrational studies of metal(II) complexes with particular reference to heterocyclic N-oxides." Doctoral thesis, University of Cape Town, 1987. http://hdl.handle.net/11427/17042.
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Includes bibliographical references.A critical examination of the characteristic N-O vibrational frequencies of aromatic N-oxides questions the widely held assignment of αN-O (840cm⁻¹) and YN-O (47oon- 1). The present investigation supports the assignments of αN-O (470cm⁻¹) and γN-O (280cm⁻¹), with the assignment of the band at 840cm⁻¹ as being vring coupled with νN-O.
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Matzumoto, Andres Esteban Perez. "A study of microphone arrays for the location of vibrational sound sources." Thesis, University of Southampton, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.305576.
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Sadeghi-Jorabchi, Houtan. "The development of vibrational spectroscopy for the analysis of fats and oils." Thesis, University of East Anglia, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303016.
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Oliva, Vidal Robert. "High-pressure optical and vibrational properties of InN and InGaN." Doctoral thesis, Universitat de Barcelona, 2016. http://hdl.handle.net/10803/400490.
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This thesis is devoted to the study of the optical and vibrational properties of indium nitride (InN) and indium gallium nitride (InGaN) at room and high-pressure conditions. For this purpose, we have employed spectroscopic tools such as absorption spectroscopy or Raman scattering in order to investigate a series of InN and InGaN thin films grown with different methods and on different substrates. For the high-pressure measurements, we have employed the diamond anvil cell technique.
High-pressure optical absorption experiments on InN epilayers have allowed us to observe the direct-to-indirect bandgap transition at 15 GPa, where wurtzite InN (w-InN) transits to the rocksalt polymorph (rs-InN). Investigating w-InN samples with different levels of residual electron density, we have been able to estimate the bandgap pressure coefficient of intrinsic w-InN (32 meV/GPa). In addition, we have measured the indirect bandgap of rs-InN and its pressure dependence. We have also performed FTIR reflectivity measurements to determine the pressure dependence of the refractive index of w-InN and rs-InN. By fitting the experimental results with a model for the dielectric function, we have determined the pressure coefficient of the high-frequency dielectric constant of both phases.
The pressure coefficient of the phonon frequencies of w-InN and their respective mode Grüneisen parameters have been measured by high-pressure Raman spectroscopy. After the wurtzite-to-rocksalt phase transition and the rocksalt-to-wurtzite backtransition upon decompression, the Raman features of both (amorphized) phases have been assigned in terms of first-principle lattice-dynamics calculations. Raman measurements on a heavily doped n-type sample have allowed us to detect a longitudinal-optical plasmon coupled mode, from which we have evaluated the pressure dependence of the electron effective mass of w-InN. With the aim of comparing the pressure behavior of the optical modes of rs-InN with that of a material exhibiting the rocksalt structure at ambient conditions, a high-pressure Raman-scattering study on rocksalt CdO is also presented.
The optical and vibrational properties of the InGaN alloy as a function of composition have also been investigated. The composition dependence of the fundamental bandgap of InGaN has been studied with optical absorption, and high-pressure photoluminescence measurements have been carried out to determine the pressure coefficients of the optical emission. In turn, the optical and acoustic phonons of InGaN have been investigated as a function of alloy composition at ambient conditions. From Raman measurements on InGaN thin films, we have found that strain importantly affects the dependence on composition of the optical modes. An analysis to correct for the strain-induced shifts as well as to assess the effect of compositional inhomogeneities on the optical phonon frequencies of InGaN is provided.
For the study of the acoustic modes of InGaN at room pressure, we have performed high-resolution Brillouin spectroscopy measurements, which have allowed us to determine the velocity of the surface acoustic waves of InGaN as a function of composition. With the aid of theoretical simulations based on the Green’s function formalism, these velocities have been used to evaluate the compositional dependence of the elastic constants of the alloy. Additional Raman-scattering measurements on InGaN/GaN superlattices have allowed us to detect the folded acoustic modes and observe the linear dispersion of the LA modes in InGaN, as predicted by elastic continuum theory.
Finally, the behavior of the optical modes of InGaN under pressure has been investigated by Raman spectroscopy on epilayers grown on GaN/Al2O3 and Si(111) substrates. This study, which
was initially aimed at determining the Grüneisen parameters of the optical phonons, has revealed that the experimental results strongly depend on the compressibility of the substrate material. We conclude that the pressure coefficients of free-standing InGaN should follow a linear dependence between those of GaN and InN.
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Panizza, M. P. "Analysis of complex integral photoelectron spectra /." Title page, contents and introduction only, 1985. http://web4.library.adelaide.edu.au/theses/09SM/09smp193.pdf.
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Hashemi, Seyed Mohammad. "Free-vibrational analysis of rotating beam-like structures, a dynamic finite element approach." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0010/NQ36276.pdf.
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Bentley, Phillip Arthur. "The application of vibrational spectroscopy to topical problems in qualitative and morphological analysis." Thesis, University of Southampton, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.307284.
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Baraga, Joseph J. (Joseph John). "In situ chemical analysis of biological tissue--vibrational Raman spectroscopy of human atheroschlerosis." Thesis, Massachusetts Institute of Technology, 1992. http://hdl.handle.net/1721.1/12875.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Whitaker College of Health Sciences and Technology, 1992.Includes bibliographical references (leaves 209-223).
by Joseph John Baraga.
Ph.D.
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Flower, Stephen Clive. "An ultrasonic study of vibrational anharmonicity in indium between room temperature and the melting point." Thesis, University of Bath, 1987. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.378139.
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Ribeiro, Marcos Pellegrini. "Inaccessible equipment monitoring via vibratory signature analysis utilising data collected by remote accelerometers." Thesis, Imperial College London, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.313689.
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Panayiotou, Helen. "Vibrational spectroscopy of keratin fibres : A forensic approach." Thesis, Queensland University of Technology, 2004. https://eprints.qut.edu.au/15953/7/Helen_Panayiotou_Thesis_ePrint-15953.pdf.
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Human hair profiling is an integral part of a forensic investigation but it is one of the most technically difficult subjects in forensic science. This thesis describes the research and development of a novel approach for the rapid identification of unknown human and other related keratin fibres found at a crime scene. The work presented here is developed systematically and considers sample collection, sample preparation, analysis and interpretation of spectral data for the profiling of hair fibres encountered in criminal cases. Spectral comparison of fibres was facilitated with the use of chemometrics methods such as PCA, SIMCA and Fuzzy Clustering, and the less common approach of multi-criteria decision making methodology (MCDM).
The aim of the thesis was to investigate the potential of some vibrational spectroscopy techniques for matching and discrimination of single keratin hair fibres in the context of forensic evidence.
The first objective (chapter 3) of the thesis was to evaluate the use of Raman and FT-IR micro-spectroscopy techniques for the forensic sampling of hair fibres and to propose the preferred technique for future forensic hair comparisons. The selection of the preferred technique was based on criteria such as spectral quality, ease of use, rapid analysis and universal application to different hair samples. FT-IR micro-spectroscopy was found to be the most appropriate technique for hair analysis because it enabled the rapid collection of spectra from a wide variety of hair fibres. Raman micro-spectroscopy, on the other hand, was hindered with fluorescence problems and did not allow the collection of spectra from pigmented fibres. This objective has therefore shown that FT-IR micro-spectroscopy is the preferable spectroscopic technique for forensic analysis of hair fibres, whilst Raman spectroscopy is the least preferred.
The second objective (chapter 3) was to investigate, through a series of experiments, the effect of chemical treatment on the micro-environment of human hair fibres. The effect of bleaching agents on the hair fibres was studied with some detail at different treatment times and the results indicate a significant change in the chemical environment of the secondary structure of the hair fibre along with changes in the C-C backbone structure. One of the most important outcomes of this research was the behaviour of the fÑ-helix during chemical treatment. The hydrogen bonding in the fÑ-helix provides for the stable structure of the fibre and therefore any disruption to the fÑ-helix will inevitably damage the molecular structure of the fibre. The results highlighted the behaviour of the fÑ-helix, which undergoes a significant decrease in content during oxidation, and is partly converted to a random-coil structure, whilst the fÒ-sheet component of the secondary structure remains unaffected. The reported investigations show that the combination of FT-IR and Raman micro-spectroscopy can provide an insight and understanding into the complex chemical properties and reactions within a treated hair fibre. Importantly, this work demonstrates that with the aid of chemometrics, it is possible to investigate simultaneously FT-IR and Raman micro-spectroscopic information from oxidised hair fibres collected from one subject and treated at different times. The discrimination and matching of hair fibres on the basis of treatment has potential forensic applications.
The third objective (chapter 4) attempted to expand the forensic application of FT-IR micro-spectroscopy to other keratin fibres. Animal fibres are commonly encountered in crime scenes and it thus becomes important to establish the origin of those fibres. The aim of this work was to establish the forensic applications of FT-IR micro-spectroscopy to animal fibres and to investigate any fundamental molecular differences between these fibres. The results established a discrimination between fibres consisting predominantly of fÑ-helix and those containing mainly a fÒ-sheet structure. More importantly, it was demonstrated through curve-fitting and chemometrics, that each keratin fibre contains a characteristic secondary structure arrangement. The work presented here is the first detailed FT-IR micro-spectroscopic study, utilising chemometrics as well as MCDM methods, for a wide range of keratin fibres, which are commonly, found as forensic evidence. Furthermore, it was demonstrated with the aid of the rank ordering MCDM methods PROMETHEE and GAIA, that it is possible to rank and discriminate keratin fibres according to their molecular characteristics obtained from direct measurements together with information sourced from the literature.
The final objective (chapter 5) of the thesis was to propose an alternative method for the discrimination and matching of single scalp human hair fibres through the use of FT-IR micro-spectroscopy and chemometrics. The work successfully demonstrated, through a number of case scenarios, the application of the technique for the identification of variables such as gender and race for an unknown single hair fibre. In addition, it was also illustrated that known hair fibres (from the suspect or victim) can be readily matched to the unknown hair fibres found at the crime scene. This is the first time that a substantial, systematic FT-IR study of forensic hair identification has been presented. The research has shown that it is possible to model and correlate individual¡¦s characteristics with hair properties at molecular level with the use of chemometrics methods. A number of different, important forensic variables of immediate use to police in a crime scene investigation such as gender, race, treatment, black and white hair fibres were investigated. Blind samples were successfully applied both to validate available experimental data and extend the current database of experimental determinations. Protocols were posed for the application of this methodology in the future.
The proposed FT-IR methodology presented in this thesis has provided an alternative approach to the characterisation of single scalp human hair fibres. The technique enables the rapid collection of spectra, followed by the objective analytical capabilities of chemometrics to successfully discriminate animal fibres, human hair fibres from different sources, treated from untreated hair fibres, as well as black and white hair fibres, on the basis of their molecular structure. The results can be readily produced and explained in the courts of law. Although the proposed relatively fast FT-IR technique is not aimed at displacing the two slower existing methods of hair analysis, namely comparative optical microscopy and DNA analysis, it has given a new dimension to the characterisation of hair fibres at a molecular level, providing a powerful tool for forensic investigations.
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Panayiotou, Helen. "Vibrational spectroscopy of keratin fibres : A forensic approach." Queensland University of Technology, 2004. http://eprints.qut.edu.au/15953/.
Full textAbstract:
Human hair profiling is an integral part of a forensic investigation but it is one of the most technically difficult subjects in forensic science. This thesis describes the research and development of a novel approach for the rapid identification of unknown human and other related keratin fibres found at a crime scene. The work presented here is developed systematically and considers sample collection, sample preparation, analysis and interpretation of spectral data for the profiling of hair fibres encountered in criminal cases. Spectral comparison of fibres was facilitated with the use of chemometrics methods such as PCA, SIMCA and Fuzzy Clustering, and the less common approach of multi-criteria decision making methodology (MCDM). The aim of the thesis was to investigate the potential of some vibrational spectroscopy techniques for matching and discrimination of single keratin hair fibres in the context of forensic evidence. The first objective (chapter 3) of the thesis was to evaluate the use of Raman and FT-IR micro-spectroscopy techniques for the forensic sampling of hair fibres and to propose the preferred technique for future forensic hair comparisons. The selection of the preferred technique was based on criteria such as spectral quality, ease of use, rapid analysis and universal application to different hair samples. FT-IR micro-spectroscopy was found to be the most appropriate technique for hair analysis because it enabled the rapid collection of spectra from a wide variety of hair fibres. Raman micro-spectroscopy, on the other hand, was hindered with fluorescence problems and did not allow the collection of spectra from pigmented fibres. This objective has therefore shown that FT-IR micro-spectroscopy is the preferable spectroscopic technique for forensic analysis of hair fibres, whilst Raman spectroscopy is the least preferred. The second objective (chapter 3) was to investigate, through a series of experiments, the effect of chemical treatment on the micro-environment of human hair fibres. The effect of bleaching agents on the hair fibres was studied with some detail at different treatment times and the results indicate a significant change in the chemical environment of the secondary structure of the hair fibre along with changes in the C-C backbone structure. One of the most important outcomes of this research was the behaviour of the fÑ-helix during chemical treatment. The hydrogen bonding in the fÑ-helix provides for the stable structure of the fibre and therefore any disruption to the fÑ-helix will inevitably damage the molecular structure of the fibre. The results highlighted the behaviour of the fÑ-helix, which undergoes a significant decrease in content during oxidation, and is partly converted to a random-coil structure, whilst the fÒ-sheet component of the secondary structure remains unaffected. The reported investigations show that the combination of FT-IR and Raman micro-spectroscopy can provide an insight and understanding into the complex chemical properties and reactions within a treated hair fibre. Importantly, this work demonstrates that with the aid of chemometrics, it is possible to investigate simultaneously FT-IR and Raman micro-spectroscopic information from oxidised hair fibres collected from one subject and treated at different times. The discrimination and matching of hair fibres on the basis of treatment has potential forensic applications. The third objective (chapter 4) attempted to expand the forensic application of FT-IR micro-spectroscopy to other keratin fibres. Animal fibres are commonly encountered in crime scenes and it thus becomes important to establish the origin of those fibres. The aim of this work was to establish the forensic applications of FT-IR micro-spectroscopy to animal fibres and to investigate any fundamental molecular differences between these fibres. The results established a discrimination between fibres consisting predominantly of fÑ-helix and those containing mainly a fÒ-sheet structure. More importantly, it was demonstrated through curve-fitting and chemometrics, that each keratin fibre contains a characteristic secondary structure arrangement. The work presented here is the first detailed FT-IR micro-spectroscopic study, utilising chemometrics as well as MCDM methods, for a wide range of keratin fibres, which are commonly, found as forensic evidence. Furthermore, it was demonstrated with the aid of the rank ordering MCDM methods PROMETHEE and GAIA, that it is possible to rank and discriminate keratin fibres according to their molecular characteristics obtained from direct measurements together with information sourced from the literature. The final objective (chapter 5) of the thesis was to propose an alternative method for the discrimination and matching of single scalp human hair fibres through the use of FT-IR micro-spectroscopy and chemometrics. The work successfully demonstrated, through a number of case scenarios, the application of the technique for the identification of variables such as gender and race for an unknown single hair fibre. In addition, it was also illustrated that known hair fibres (from the suspect or victim) can be readily matched to the unknown hair fibres found at the crime scene. This is the first time that a substantial, systematic FT-IR study of forensic hair identification has been presented. The research has shown that it is possible to model and correlate individual¡¦s characteristics with hair properties at molecular level with the use of chemometrics methods. A number of different, important forensic variables of immediate use to police in a crime scene investigation such as gender, race, treatment, black and white hair fibres were investigated. Blind samples were successfully applied both to validate available experimental data and extend the current database of experimental determinations. Protocols were posed for the application of this methodology in the future. The proposed FT-IR methodology presented in this thesis has provided an alternative approach to the characterisation of single scalp human hair fibres. The technique enables the rapid collection of spectra, followed by the objective analytical capabilities of chemometrics to successfully discriminate animal fibres, human hair fibres from different sources, treated from untreated hair fibres, as well as black and white hair fibres, on the basis of their molecular structure. The results can be readily produced and explained in the courts of law. Although the proposed relatively fast FT-IR technique is not aimed at displacing the two slower existing methods of hair analysis, namely comparative optical microscopy and DNA analysis, it has given a new dimension to the characterisation of hair fibres at a molecular level, providing a powerful tool for forensic investigations.
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McQuilken, Andrew Lynn. "Some pulsed IR and UV studies of vibrational energy transfer processes in selected triatomic molecules." Thesis, Queen's University Belfast, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.336132.
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Medina, Gerardo Juan. "Ligand isotope vibrational spectroscopic and DFT studies of Pt(II) and Cu(I) complexes." Thesis, Rhodes University, 2005. http://hdl.handle.net/10962/d1004982.
Full textAbstract:
Ligand-isotope labelling studies were performed on Zeise’s salt derivatives with pyridine N-oxide and quinoline N-oxide, their perdeuterated and O-18 isotopomers, C₂D₄ and ¹³CO, and the results of the vibrational analyses are reported. The isotopomers are modelled utilizing DFT calculations at the B3LYP level with the 6-31 G** basis set, and a pseudopotential level for the Pt atom. The calculated and observed structure and vibrational spectra correlate well. The crystal structures of [Pt(C₂2H₄)(pyO)Cl₂] and [Pt(CO)(quinO)Br₂] are reported. The frequency for the νPt-O vibration, ambiguously assigned in the literature, is here assigned unequivocally at 400 cm⁻¹. Previously observed, but inadequately described phenomena are addressed: the νN-O vibration in substituted quinoline N-oxides has been assigned previously at significantly different frequencies, depending on the nature of the substituent. This suggests that there is no specific mid-ir band associated with a high N-O character. A suitable explanation is presented for this phenomenon, showing that in low symmetry systems (eg. quinO) the N-O stretch is dispersed among several modes, whereas in high symmetry systems (eg. pyO) only a few limited modes have a high N-O character. A theoretical study of Cu(I) carbonyl compounds with macrocyclic ligands is presented. Local and global HSAB parameters applied to the donor and Cu atoms are used to explain the observed reactivities and the available spectroscopic data. Extended to [Cu(CO){H₂N(CH₂)[subscript n]NH(CH₂)[subscript m] NH₂}] BPh₄ (where n = 2, m = 2, 3 and n =3, m = 3, 4) and their -d₅ and ¹³CO isotopomers, subtle differences obtained experimentally for the CO stretching frequency in this series have been reproduced in the DFT calculations at the B3LYP level, using the 6-31 G* and 6-31 G** basis sets. Several properties (ligand pK[subscript a] values, νCO frequencies, etc.) correlate with some HSAB descriptors. Vibrational analyses are presented of Cu(I) carbonyl Schiff-base derivatives of N-Benzylidene-N’-[2-(benzyilidene-amino)-ethyl]-ethane-1,2-diamine, {2,2N3(C₆H₄R)₂}, and their -d₅ and ¹³CO isotopomers. The crystal structure of [Cu(CO){2,2N3(C₆H₅)₂}]BPh₄ is reported. From geometry optimizations and the HSAB descriptors, spectroscopic trends ([n]Cu-N and [nu]CO) are related to calculated global hardness and the Hammett substituent parameters, and are discussed in terms of σ-donation and π-backbonding of Cu- CO.
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Tomerini, Daniele. "A computational analysis of the vibrational absorption of molecular solids in the teraherz range." Thesis, University of Cambridge, 2012. https://www.repository.cam.ac.uk/handle/1810/243650.
Full textAbstract:
In this thesis, we deal with the application of transmission terahertz spectroscopy as an analysis tool for the study of molecular solids, in particular organic crystals of pharmaceutical interest. Most of the work has been performed using two computational packages aimed at the interpretation of the spectra, one based on molecular forcefields (DMACRYS), the other on solid state density functional theory (CASTEP). We compare low temperature determinations of several molecular organic crystals to calculated spectra, and attempt to assign calculated modes of vibrations to absorption peaks, based on the similarity in frequency between the measured and calculated peaks. One of the main aims of this work is to establish the limits of our forcefield approach, which is based on the approximation that the intramolecular degrees of freedom can be neglected. We analyse the normal modes of vibration calculated with CASTEP, evaluating the amount of rigid molecule rotational and translational contribution to each eigenvector as a function of frequency, in order to validate our forcefield approach. We also compare the two sets of eigenvectors from the DMACRYS and CASTEP calculations to assess the similarity between the two approaches. We perform the same eigenvectors analysis on several hydrate systems in order to understand the role of water in the lattice dynamics of crystalline hydrates. We attempt a classification of the eigenvectors based on the strength of the forces involved in the molecular vibrations and based on the amount of the water contribution to each normal mode. A set of isostructural crystals is analysed in order to understand the effect that small variations (in the molecular formula and in the unit cell arrangement) have on the measured and calculated absorption spectra of a crystal. Finally, we discuss the use and development of computational methods that allow us to have a more realistic description of the molecular electrostatic in DMACRYS.
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Jones, Kolton K. "An Integration Setup if the in-situ Mass and Spectroscopic Analysis for Volatile Liquids or Solids." TopSCHOLAR®, 2018. https://digitalcommons.wku.edu/theses/2064.
Full textAbstract:
To help address the growing need for more and better sensors, an attempt was made to produce an in-situ mass and spectroscopic analysis of liquid and solid samples, to characterize samples and sensors. Spectroscopic analysis consisted of Raman and FTIR where mass measurements were carried out. The sample or sensor’s holder would allow for spectroscopic analysis as well as expose the sample to high temperatures and various chemicals. While Raman and FTIR were successful in producing reliable and consistent data, the constructed watt balance was not. This failure was a result of eliminate vibrational noise.
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Rafferty, M. P. "Studies on the tonal qualities of violins : vibrational behaviour of the treble from the new violin family." Thesis, Bucks New University, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376440.
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Leyßner, Felix [Verfasser]. "Analysis of functional organic molecules at noble metal surfaces by means of vibrational spectroscopies / Felix Leyßner." Berlin : Freie Universität Berlin, 2011. http://d-nb.info/1026265657/34.
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Adamczyk, Aleksandra Katarzyna. "Analysis of the high-resolution ro-vibrational spectrum of DC3N in the far and mid infrared regions." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/21732/.
Full textAbstract:
Cyanoacetylene HC3N is a molecule of great astronomical importance and it has been observed in many interstellar environments. Its deuterated form DC3N has been detected in number of sources from external galaxies to Galactic interstellar clouds, star-forming regions and planetary atmospheres. All these detections relied on previous laboratory investigations, which however still lack some essential information concerning its infrared spectrum. In this project, high-resolution ro-vibrational spectra of DC3N have been recorded in two energy regions: 150 – 450 cm-1 and 1800 – 2800 cm-1. In the first window the ν7← GS, 2ν7 ← ν7, ν5 ← ν7, ν5+ν7 ← 2ν7, ν6+ν7 → 2v7, 4ν7 ← 2ν7 bands have been assigned, while in the second region the three stretching fundamental bands ν1, ν2, ν3 have been observed and analysed. The 150 – 450 cm-1 region spectra have been recorded at the AILES beamline at the SOLEIL synchrotron (France), the 1800 – 2800 cm-1 spectra at the Department of Industrial Chemistry “Toso Montanari” in Bologna. In total, 2299 transitions have been assigned. Such experimental transition, together with data previously recorded for DC3N, were included in a least-squares fitting procedure from which several spectroscopic parameters have been determined with high precision and accuracy. They include rotational, vibrational and resonance constants. The spectroscopic data of DC3N have been included in a line catalog for this molecule in order to assist future astronomical observations and data interpretation. A paper which includes this research work has been published (M. Melosso, L. Bizzocchi, A. Adamczyk, E. Cane, P. Caselli, L. Colzid, L. Dorea, B. M. Giulianob, J.-C. Guillemine, M-A. Martin-Drumel, O. Piralif, A. Pietropolli Charmet , D. Prudenzano, V. M. Rivillad, F. Tamassia, Extensive ro-vibrational analysis of deuterated-cyanoacetylene (DC3N) from millimeter wavelengths to the infrared domain, Jour. of Quant. Spectr. and Rad. Tran. 254, 107221, 2020).
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Harvey, Pierre Dominique. "Applications of vibrational spectroscopy and NMR spin-lattice relaxation time measurements to organometallic and organic molecular crystals." Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=73986.
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Aykas, Didem P. "Verification of Ingredient Labels in High-Risk Oils and Fruit Juices by Using Vibrational Spectroscopy Combined with Pattern Recognition Analysis." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1555644726731438.
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INZARULFAISHAM, Abd Rahim, and Hideyuki AZEGAMI. "Solution to Shape Optimization Problem of Linear Elastic Continuum with Prescribed Vibrational Eigen-mode." 日本機械学会, 2001. http://hdl.handle.net/2237/12180.
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Herring, Jennifer M. "Cranktrain modeling and analysis of connection rod vibrational effects on the overall performance of Otto cycle engines." Thesis, Wichita State University, 2014. http://hdl.handle.net/10057/10961.
Full textAbstract:
Since connecting rods are a major component in the smooth and efficient running of an engine, how they affect the overall performance is important. The durability of connecting rods in repeated and cyclic operations is significant to the health and performance of an engine. The purpose of this research is to determine what effects the vibrations of connecting rods have on the overall performance of Otto cycle engines. Some studies have been conducted on the static vibration of connecting rods as well as connecting rods in dynamic systems, but those studies only considered the connecting rod design.
Modeling, dynamic analysis, and vibrational analysis are conducted using two different software programs, MSC Adams/View and FEV Virtual Engine. Two different engine configurations are modeled: inline and vee; the results from the two programs are then compared. The data is also checked against vibrational analysis from literature sources as well as having the general performance of the pistons cross-checked against real engine data. The MSC Adams/ View models are composed of simplified cranktrains and forces; while those of FEV Virtual Engine are modeled after actual dimensions and workings. It is determined that the vibrations of connecting rods, under typical operating conditions and material/geometrical properties, do not greatly affect the overall performance of an engine.Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering
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Ali, H. R. H. "Vibrational spectroscopic techniques (Raman, FT-IR and FT-NIR spectroscopy) as a means for the solid-state structural analysis of pharmaceuticals." Thesis, University of Bradford, 2009. http://hdl.handle.net/10454/3343.
Full textAbstract:
The aim of this work was to assess the suitability of vibrational spectroscopic techniques (Raman, FT-IR and FT-NIR spectroscopy) as a means for the solid-state structural analysis of pharmaceuticals. Budesonide, fluticasone propionate, salbutamol hemisulfate, terbutaline hemisulfate, ipratropium bromide, polymorphic forms of salmeterol xinafoate and two polymorphic forms of sulfathiazole were selected since they are used in the management of certain respiratory disorders and from different chemical and pharmacological entities along with some pharmaceutical excipients. Conventional visual examination is not sufficient to identify and differentiate spectra between different pharmaceuticals. To confirm the assignment of key molecular vibrational band signatures, quantum chemical calculations of the vibrational spectra were employed for better understanding of the first five selected drugs. The nondestructive nature of the vibrational spectroscopic techniques and the success of quantum chemical calculations demonstrated in this work have indeed offered a new dimension for the rapid identification and characterisation of pharmaceuticals and essentially warrant further research. The application of simultaneous in situ Raman spectroscopy and differential scanning calorimetry for the preliminary investigation of the polymorphic transformation of salmeterol xinafoate polymorphs and two polymorphic forms of sulfathiazole has also been explored in this work leading to the development of a new method for the solid-state estimation of the transition temperature of entantiotropically related pharmaceutical polymorphs which represents the first analytical record of the use of this approach for pharmaceutical polymorphs.