This thesis describes the development of a generic design methodology for variable camber flap systems for transport aircraft, intended to be used for cruise and low-speed operations. The methodology was structured after several revisions were performed on conventional high-lift device design methodologies for existing transport aircraft. The definition and detail explanations are given at every phase of the methodology. A case study was performed in order to give an example of the implementation of the methodology where a transport aircraft called A TRA, a design study from previous PhD report, was taken as a model. Experimental work could not be performed, due to budget constraints, so the case study was only carried out using computer-based analyses. Software packages such as MSES-code (a Computational Fluid Dynamic software), CATIA and PATRANINASTRAN were used for this case study to analyse aerodynamic characteristics, layout as well as simulation and structure analyses respectively. The results obtained showed that it was practically feasible to deploy such a high-lift device to transport aircraft when the effect from aerodynamic loads gave minimum effect on structural deformation. The deflections of the flap as well as spoilers under critical loads were below the allowable limits, which had a minimal effect due to the additional lift force generated from the movable surfaces.

An explicit Mueller-Regge model (with poles only) is constructed for the investigation of single-particle-inclusive processes in the quasi-two-body and triple-Regge subspace of the fragmentation region. The model is then applied in studies of nucleon production processes. The inclusive cross sections are considered and compared with the available data. The qualitative agreement between the cross section data and the model is reasonable, but the model is not satisfactory in details. Regge cuts are introduced into the model via the absorption model prescription. Then nucleon production processes are reinvestigated in this modified model and the polarization of the produced nucleon is predicted. The model is applied to Lambda production (in a nucleon interaction), and the agreement between theoretical prediction and the experimental data for the polarization of the Lambda in the small p region is remarkable. Finally, the model is applied to tensor meson production and the cross section and the spin density matrix elements are predicted.

This thesis is presented in two distinct parts. In part one, the single lepton yield due to internal conversion of soft virtual photons in high energy proton-proton collisions is calculated using soft photon techniques. Photons originating in bremsstrahlung of charged hadrons, directly produced photons and interference effects are considered. The result is compared with the experimental e/ir ratio as a function of transverse momentum. In part two, a Mueller-Regge model for the process is constructed and compared with newly available inclusive cross section data. Cut corrections are required for baryon exchange by the Carlitz-Kislinger prescription for removing unobserved parity partners and accordingly absorption effects are calculated. The conventional [delta] baryon trajectory is found to be satisfactory, contrary to other reports.

An explicit Mueller-Regge model is constructed for the investigations of one-particle-inclusive 2 processes in the fixed-M and triple-Regge region. The model is then applied in the studies of [delta] production and vector and tensor meson productions. The inclusive cross sections and density matrices of the decaying produced resonances are considered and compared with the available data. The qualitative behaviour of the cross section data can be approximately accounted for by the model, but the model is not satisfactory in details. By analogy with two-body processes absorption is introduced and the resultant model with cuts is used in the reinvestigations of the data. There is some improvement in the agreement between the model and the data with the introduction of absorption.

The application of pressure to chemical substances can change their physical properties (optical, magnetic, and electrical) and it can also be used to alter some chemical reactions. The need for compatible pressure generating instruments is constantly growing in various high pressure (HP) researches. The work described in this thesis is focused on development, construction, testing of several high pressure cells of novel design. These designs were developed to meet the requirements of different research collaborations. The main objective of this project is to develop high pressure cells for magnetic studies in the magnetic properties measurement system known as MPMS, which is the most popular commercial magnetometer nowadays. Three high pressure cells were designed and tested for different type of magnetic measurements. The first design presented in this thesis is a cylinder type pressure cell which is specially designed to measure the magnetic susceptibility of the pressure-sensitive material under pressure. The cell is driven by compressed helium gas which allows the internal pressure to be adjusted with small increments (1 MPa) through the regulator of the external gas cylinder. The cell was made of non-magnetic beryllium copper alloy and designed to work up to 100 MPa at 400 K temperature. The design was verified with finite element analysis (FEA) simulation and its sample volume was optimised to provide large sample capacity which allows high quality data to be collected in the MPMS. Modified from the earlier turnbuckle magnetic diamond anvil cell (TM-DAC) reported in Konstantin V. Kamenev (KVK) group, the second high pressure cell presented in this thesis is an opposed diamond anvil pressure cell. The working mechanism of this cell is based on the turnbuckle principle. The cell was specifically developed for iHelium3 system which is a add-on cryostat of the MPMS. The cell was coded TM-3He-DAC to distinguish with the original TMDAC. The cell is 6 mm in diameter and 7 mm in length, which are smaller than the dimensions of the predecessor (TM-DAC). Copper titanium alloy was used in building the cell to further reduce the magnetic background from the cell. The cell is capable of achieving close to 5 GPa sample pressure in the loading test and the magnetic background is significantly lower than the TM-DAC. The development of this cell enables high pressure magnetic measurements to be performed at extreme low temperature (0.5 K) in the iHelium3 system. The third high pressure cell developed for the MPMS is also a turnbuckle diamond anvil cell, however, all the material used in the cell is non-metallic to enable high-pressure ac magnetic measurement to be performed. An advanced high strength polymer was assessed using finite element analysis and experimental testing. The performance and failure modes for the key components of the cell working in tension and in compression were evaluated and the ways for optimising the designs were established. The cell is coded PTM-DAC in this thesis and the composite gasket was also developed and tested for the PTM-DAC. The cell is approximately 14 mm long, 8.5 mm in diameter and was demonstrated to reach pressures of 5.6 GPa. Ac susceptibility data collected on Dy2O3 and U6Fe demonstrated the performance of the cell in magnetic property measurement and confirmed that there was no screening of the sample by the environment which typically accompanies used of conventional metallic high pressure cells in oscillating magnetic fields. Based on the experience of from the development of above two turnbuckle diamond anvil cell, a turnbuckle sapphire anvil cell (T-SAC) was developed in this project for high-pressure neutron scattering. Commercial spherical sapphire were used as anvil in the cell as they are much more cost effective if compared to the diamond anvil. The developed T-SAC can generate and maintain sample pressures above 6 GPa with a sample volume 6 X 10-² mm³ which is 6 times that of conventional diamond anvil cell (DAC). Failure analysis was performed on the sapphire anvil to gain a better understanding of the failure mechanism of the spherical sapphire anvil. The cell had been used in measuring the crystal structure of single crystal niobium at 1.6 GPa through small angle neutron scattering (SANS) technique. The cell is less than 16 mm in length and 14 mm in diameter, it is the smallest sapphire anvil cell to date. The miniature feature allow it can be fit into most cryostat of modern scientific instrument without difficulties. Lastly, two piston-cylinder type high pressure cells were developed for high-pressure chemistry studies. These cells were designed to pressurise large amount of liquid sample (particular for water-based sample) up to 800 MPa in a controllable manner. Each design is presented separately with stress analysis in FEA and a description of the working mechanism. Hoop strain at the external surface of the cell was measured and then the internal pressure was calculated through the Lam´e equation. After that, the load and attainable internal pressure was calibrated for the users. These cells have been used in the high-pressure study of salicylaldoximes process, bio-diesels decomposition and crystallization, material polymerisation and pharmaceutical experiments.

Most high speed vessels are fitted with powerful high speed engines which are installed in confined spacesa nd, as a consequencec, ausea n extremely high level of noise and vibration. Often structure-borne sound power is transmitted to a sound carrying structure from a source via a number of contact points. In turn, the noise and vibration are propagated in the structure and could possibly cause an undesired noise radiation. In this study, a model for predicting power flow based on the mobility theory has been addressed. The unique parts of the study include the establishment of the relationship of mobility functions with respect to four-pole parameters and the dynamic stiffness coefficients of a coupled machine/mount/foundation system. Also expressions to represent the sound input power, the output power and the transmitted power in relation to mobility functions are clarified. From a detailed analysis of relevant literature, it is shown that no validated models for predicting the propagation of structure-bome noise within the intermediate frequency range of 125 Hz to lkHz exist. As a consequence, a new numerical stress wave model has been developed to bridge this knowledge gap. This innovative approach extends the earlier works of Cremer, Heckl and Ungar in the field of stress wave propagation. Finally, a novel holistic model has been developed to line up the transmission, propagation and radiation predictions of a machine induced noise and vibration in ship's structure to take in account the fluid-structure interaction effect. A number of experiment measurements have been performed to validate the established models. From the comparisons, the prediction models are shown to be credible with an accuracy higher than 95 per cent. The established models are of a generic nature and can be applicable to diverse engineering fields regarding to the predictions of structure-borne noise and vibration transmission, propagation and radiation. Applications of these models to characterize the vibration reduction countermeasures,a s in the case of resilient mounts and squeeze-film damping plates, from a machine are also discussed.

No description available.

<p> This dissertation shows the first evidence of the process <i>e</i>⁺<i>e</i>^&minus; &rarr; &gamma;&eta;<i>_c</i>(1<i>S</i>) using data collected by the BESIII experiment operating at BEPCII. This process can be used as a probe to study the nature of recently discovered charmonium-like Y states between 4.0 and 4.6 GeV, including the <i>Y</i>(4260) and <i>Y</i>(4360). Data collected at six center-of-mass energies are analyzed, namely: 4.01, 4.23, 4.26, 4.36, 4.42, and 4.60 GeV, corresponding to a total integrated luminosity of 4.6 fb^&minus;1. We measure the Born cross section, &sigma;<i>_E</i>(<i>e</i>⁺<i>e</i>^&minus; &rarr; &gamma;&eta;<i>_c</i>(1<i> S</i>)), at each energy using a combination of twelve &eta;<i>_c</i>(1<i>S</i>) decay channels. Because the significance of the signal is marginal at each energy (&le; 3.0&sigma;), we also combine all six energies under various assumptions for the energy-dependence of the cross section. If a <i>Y</i>(4260) is assumed, we measure &sigma;4_.26(<i>e</i>⁺<i>e</i>^&minus; &rarr; &gamma;&eta;<i>_c</i>(1<i>S</i>)) = 2.11 &plusmn; 0.49 (stat.) &plusmn; 0.33 (syst.) pb with a significance of 4.2&sigma;. With our current statistics we are unable to distinguish the <i> Y</i>(4260) process from others.</p>

Thesis (Ed.D.)--Boston University / PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / 2031-01-01

Thesis (Ed.M.)--Boston University