Thesis (M.S. in Aeronautical Engineering)--Naval Postgraduate School, September 1990. / Thesis Advisor(s): Collins, Daniel J. Second Reader: Schmidt, Louis V. "September 1990." Description based on title screen as viewed on December 29, 2009. DTIC Identifier(s): Flight control systems, control theory, computer files, theses, input output processing, F-18 aircraft. Author(s) subject terms: Modern control theory, H infinity control theory, H2 control theory, multivariable robustness, F-18 control design or synthesis, super augmented aircraft. Includes bibliographical references (p. 110). Also available in print.

Includes bibliographical references (p. 121-124).

The last years a TC-sensing module called HSS-440 has been developed at AppliedSensor. The sensor is used in hydrogen powered cars to detect H2-leakages. TC-sensing is a technique that uses small changes in thermal conductivity when H2 is present to determine concentrations. Today these small changes are estimated with a prediction model that uses several hundreds of parameters. A sensor substrate from a new manufacturer is now introduced. This means an opportunity to look over the current solution. The task for this thesis is to investigate system properties and new solutions regarding a prediction model with minimal need for calibration. System properties are investigated and relations for heat flow and influence of H2 are established. In the process an earlier not known nonlinearity are proved to exist. From this, a new open loop nonlinear greybox model is estimated and the nonlinearity are concluded to improve the model. The model is then closed with an earlier implemented PI-regulator and concluded to be useful for H2-predictions. The new model also utilizes 11 parameters instead of hundreds which is a big improvement. / Sista åren har en sensor, med beteckningen HSS-440, mätandes Termisk konduktivitet utvecklats på AppliedSensor. Sensorn används för att upptäcka läckage av H2-gas i vätgasdrivna bilar. Vid Termisk Konduktivitets mätning används små förändringar av den termiska konduktiviteten, då H2 är närvarande i det omgivande mediumet, som ett mått på koncentrationen. Idag änvänder prediktionsmodellen flera hundra parametrar för att skatta denna koncentration. Nu introduceras ett sensorsubstrat från en ny tillverkare, vilket innebär ett bra tillfälle att se över den gamla lösningen. Syftet med examensarbetet är därför att undersöka nya systemegenskaper i och med introduktionen av det nya sensorsubstratet samt nya lösningar på en prediktionsmodel med ett minimalt behov av kalibrering. Systemegenskaperna undersöks och samband för värmeflöden och H2's påverkan på systemet fastställs. Vid denna undersökning upptäcks en tidigare okänd olinjäritet. Utifrån detta bestämms en ny olinjär greybox modell där den nyfunna olinjäriteten bevisas förbättra modellen. Modellen sluts med en tidigare implementerade PI-regulator och bevisas vara användbar vid H2-prediktion. Den nya modellen använder även bara 11 parametrar istället för flera hundra vilket är en stor förbättring.

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Title:EFFECTS OF THE PROMINENCE OF FIRST HARMONIC ON THE PERCEPTION OF BREATHINESS AND VOWEL IDENTITY Authors: Emily Lin, Samuel Sloane,and Donal Sinex Background: Human communication relies on adequate speech intelligibility to enable the comprehension of verbal messages. Dysphonia (i.e., aberrant voice) may not only result in distraction during communication but also interfere with speech intelligibility leading to a communication barrier. One voice quality commonly found in dysphonia is breathiness, which is related to the presence of excessive airflow during phonation due to incomplete glottal closure. Breathiness has been associated with the prominence of the first harmonic (H1) in the acoustic analysis of voice. Objectives: This study aimed to determine whether excessiveness in the first harmonic (H1) dominance, which has been associated with breathy voice, may result in the perception of breathiness and compromise vowel intelligibility. Methods: Participants included 10 female and 10 male normal-hearing adults, aged between 19 to 40 years. Participant’s tasks included a “breathiness rating” and a “vowel identification” task. For the “breathiness rating” task, a direct magnitude method was employed for the participant to rate a 500-ms long vowel (/i/ and /a/) segmented from sustained vowel phonation. For the “vowel identification” task, the vowel stimuli were segmented out from running speech (“Rainbow passage”) and the participants were asked to listen to one vowel stimulus (/i/, /a/, or /o/; duration: 60 ms) at a time and indicate which vowel (i.e., /i/, /e/, /a/, /o/, or /u/) they perceived the stimulus to be. The vowel stimuli included processed and unprocessed voice recordings of individuals with and without voice disorders. Voices showing the lowest, median, and highest amplitude differences between the first two harmonics (H1-H2) were chosen from a voice database for female and male voices respectively. The 18 selected vowel signals (3 vowels X 3 H1-H2 levels X 2 speaker genders) were processed through 12 signal manipulation conditions. The 12 signal conditions involved increasing or decreasing the H1 amplitude of the original signals in six 2-dB interval steps in both directions. Results: For the “breathiness rating” task, the five-way (3 vowels X 2 speaker genders X 3 H1-H2 levels X 13 signal conditions X 2 listener genders) Mixed Model Analysis of variance (ANOVA) conducted on the breathiness scores for normal speakers and voice patients separately showed significant findings for various main and interaction effects, such as a significant speaker gender by signal condition by vowel interaction effect on the perception of breathiness [F(12, 96) = 1.95, p = 0.038] for normal voice. An increase of H1-H2 through signal manipulation led to an increase of perceived breathiness only when performed on the vowel /i/ produced by female normal speakers. As for the “vowel identification” task, a relationship between H1-H2 increment and vowel intelligibility was found but the relationship was affected by vowel type, speaker gender, and H1-H2 level. With all vowel types, speaker genders, and H1-H2 levels combined, a significant signal condition effect on the number of incorrect vowel identification was found (2 = 188.585, df = 10, p < 0.001). Generally, it appeared that an increase of H1-H2 would worsen the identification of /i/ but enhance that of /o/. Conclusion: The relationship between H1 dominance and perceived breathiness was non-linear. Factors found to disrupt the linear relationship included speaker gender, vowel type, and the extent of H1 dominance. In addition, there was evidence that acoustic manipulation of the H1 amplitude would affect vowel intelligibility and the relationship between vowel intelligibility and H1-H2 values also vary by speaker genders and vowel types.

Coal gasification is currently being developed as a cleaner alternative to conventional combustion technology. To optimise H2 production in this process, a water gas shift reaction is utilised to convert all CO with H2O to produce CO2 and H2. Typically industrial processes involve a two-step reaction system followed by a downstream H2 purification system, though attracting significant inefficiencies and high capital costs. Replacing a conventional unit process with a membrane reactor in this application is foreseen to provide major advantages: • Removing H2 from the reaction in-situ, a membrane reactor can minimise downstream processing and associated capital and operational costs. • Shift the reaction to higher conversions, improving efficiencies and reducing CO in the outlet. • Provide a purified H2 stream for use in PEM fuel cells, while concentrating the CO2 stream at high pressure for possible sequestration. If the concept of membrane reactor is to be adopted in coal gasification, important material improvements and operational challenges must be overcome before commercialisation can be realised. In addition, the water gas shift reaction has only recently gained interest for membrane reactors and is currently lacking comprehensive research on the effects of operating conditions on both the conversion and separation found within the unit. To this end, these are strong motivations of this work to contribute with knowledge in this field of research. This thesis examines the effects of operating conditions such as temperature, pressure, space velocity, sweep gas rate and feed water ratio on the performance of a water gas shift membrane reactor as compared with a conventional reactor. Novel cobalt silica molecular sieve membranes were used with conventional low temperature water gas shift reaction CuZnAl2O3 catalysts. Two type of membrane reactor configuration were investigated: a small flat template with catalyst on the feed side, and a scale up tube membrane with catalyst placed also in feed stream, the inner shell of the tube membrane. The cobalt silica membranes complied with activated transport, following a flux dependency gas permeation, where He and H2 permeance increased with temperature whilst N2, CO and CO2 showed the opposite effect. Best single gas selectivities were very high, with values of 4500 (He/N2) and 1100 (H2/CO2). In addition, the energy of activation for He and H2 was also very high, in excess of 9-10 kJ.mol-1, clearly indicating the high quality of the membranes employed in this study. It was found that the MR improved CO conversions for a range of space velocities as a function of temperature, which was attributed to both activate transport property of the membrane and increased conversion. Below equilibrium limits this provided an improved H2 production of 5 – 12% at 200-250oC as the removal of H2 through the membrane allowed enhanced conversion. With a set feed rate, the optimum advantage of the MR was seen at a water ratio of 1 as the lower equilibrium limits allowed greater potential for conversion enhancement. With increasing excess water this advantage decreased from 7% down to 0.5% at 300oC. The use of pressure and sweep rate was used to optimise the membranes permeation rate and selectivity. While pressure (or driving force) provided the highest potential for increasing permeation (or flow rate), temperature in tandem with pressure provided the greatest improvement in membrane selectivity, thus increasing H2 concentration from 95 – 99% in the permeate stream. Detailed study of permeate concentrations with changing conditions was undertaken to provide an understanding of the transport properties of silica membranes. It was observed that membrane selectivity and permeation decreased with the gas composition (ie Single>Binary>Ternary). Nevertheless, for separation of a ternary mixture at increased temperatures (250oC) the membrane could provide up to 99% purified H2 while reducing CO down to 700ppm. Competitive gas permeation regimes are an industrial reality which is seldom addressed in membranes for high temperature gas separation. The effect of gas mixtures on permeation and selectivity was attributed to several factors: chemical potential (or driving force) of the feed gas mixture, blockage of micropores by large molecules (CO2 and CO) which in turn affects the percolation of H2. As a result, gas separation was reduced for higher CO and CO2 feed concentrations, leading to a significant reduction in the H2 flow rate. Temperature played a vital role in this competitive process, as H2 diffusivity and CO, CO2 adsorption followed an inverse trend. Thus, increasing temperature led to higher H2 pore diffusivity, while decreasing the competitive effect of CO and CO2 adsorption. The use of cobalt modified silica to improve the hydrothermal stability of the membranes was investigated for use in the water gas shift reaction. It was found that the addition of cobalt stabilised the silica pore network, maintaining microporosity after exposure to steam. This is validated with long term stability testing in a water gas shift membrane reactor, where it was seen that the membrane could provide up to 95% H2 concentration in the permeate for over 200hrs of MR operation. This provided novel work, establishing the feasibility of these membranes for long term testing and operation in an industrial WGS MR.

Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2005. / On t.p. "2" is lower case and "[infinity]" appears as the infinity symbol. Includes bibliographical references (leaves 110-116). Also available in electronic version.

This thesis examines literary images of masculinity and femininity, their function and depiction in marriage roles and homo-social relationships in the context of crisis: wifely adultery. The study is heavily reliant upon vernacular texts, especially Old French works from the twelfth and thirteenth century including works from the genres of romance, lais, fables, and fabliaux. Latin works including historia and prescriptive texts such as customaries, penitentials, etiquette texts and medical and canon law treatises are also used to contextualise themes in the Old French literature. The introduction summarises modern literary and historical criticism concerning sexuality in the Middle Ages. It then discusses the influences of the Church, philosophy, medicine, natural theory and society on medieval definitions of sexuality to contextualise the literature which is focal to this thesis. The following four chapters each consider a single character in the adulterous affair: the adulteress, the husband, the lover and the accuser. The literary images of each character are analysed in detail revealing the diversity of depictions between and also within genres. This enables the identification of medieval sexual constructs, challenging some previous critiques of representations of sexuality in the Middle Ages. The final chapter explores the language by which the sexual act is presented. Furthermore, it shows how language is used and occasionally abused in committing, prosecuting and evading punishment for adultery and how it can be wielded as a weapon of women. Through the focus of a body of literature rich in depictions of sexuality, this thesis questions the misogynist overtones often attributed to medieval literature. The diversity of images shows that the literature illustrates a wide range of opinions and ideas reflective of the complexity of sexuality in medieval society.

A major goal of the EU Commission in the area of direct taxation is the introduction of a common consolidated corporate tax base (CCCTB) in Europe. While hardly discussed in the literature, such a system would limit national discretion over tax depreciation. In a sample of up to 47 countries, we find that the probability of a tax reform that improves the depreciation allowances increases, if the macroeconomic situation is weak. This suggests that changes in depreciation allowances are used as a fiscal instrument for stabilization. A common consolidated tax base deprives national governments from implementing investment incentives via accelerated depreciation. This paper discusses the possible implementation of a hybrid system that combines features of formula apportionment and separate accounting. Such a hybrid system may substantially mitigate transfer pricing problems and other tax planning issues, whilst preserving national discretion over depreciation allowances. / Series: WU International Taxation Research Paper Series

Strong dependency on fossil fuels and the associated price and supply chain risk increase the need for more efficient utilisation of existing non-renewable energy sources. Carbon capture and hydrogen purification technologies are expected to play a key role in the future low-carbonised energy matrix. Integrated Gasification Combined Cycles (IGCCs) are one of the emerging clean coal technologies which pave the way for producing power from coal with a higher net power efficiency than conventional PC-fired boiler power plants. It is also advantageous that in an IGCC power plant a carbon capture unit can be applied to a stream having a very high CO2 partial pressure ahead of gas combustion that would not be available in case of a PC-fired boiler power plant, leading to less energy penalty involved in carbon capture. At the same time, the production of ultrapure hydrogen is both a sought target and an appropriate environmental solution because it is commonly utilised as feedstock in refineries’ hydrotreaters and hydrocrackers as well as energy carrier in fuel cells. A high purity of hydrogen has been commercially produced out of raw synthesis gas using a Hydrogen Pressure Swing Adsorption (H2 PSA) process. In this thesis, it was aimed to design and optimise a bespoke H2 PSA system tailored for a decarbonised syngas feed originating from a carbon capture unit. Therefore, a novel H2 PSA has been studied that is applied to an advanced IGCC plant for cogenerating power and ultrapure hydrogen (99.99+ mol%) with pre-combustion CO2 capture. In designing the H2 PSA, it is essential to increase the recovery of ultrapure hydrogen product to its maximum since the power consumption for compressing the H2 PSA tail gas up to the gas turbine operating pressure should be minimised to save the total auxiliary power consumption. Hydrogen recovery was raised by increasing the complexity of the PSA step configuration that allows a PSA cycle to have a lower feed flow to one column being used for adsorption and more pressure equalisation steps. An in-depth economic analysis was carried out and discussed in detail. The industrial advanced IGCC performances have also been improved by process integration between the H2 PSA unit and other units in the plant.