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In this chapter, I explore the conceptual and practical dilemmas involved in labelling artistic work as ‘Muslim’. Using the Black Arts Movement (BAM) and Contemporary Christian Music (CCM) as useful comparators, I evaluate the potential consequences of labelling artistic expression. The BAM failed to mould an independent and isolated African American culture, but it did radically influence wider American society. Conversely, CCM failed to break out into mainstream music culture, but it has succeeded in helping to sustain and enrich a vibrant evangelical Christian community. As I argue, the successes and difficulties of BAM and CCM highlight the opportunities and restrictions that exist when labelling any self-conscious arts movement. This is particularly true for the artistic expression in the UK, which is potentially bound together quite inextricably with wider issues of both ethnicity and public religion.

In this chapter, I explore the conceptual and practical dilemmas involved in labelling artistic work as ‘Muslim’. Using the Black Arts Movement (BAM) and Contemporary Christian Music (CCM) as useful comparators, I evaluate the potential consequences of labelling artistic expression. The BAM failed to mould an independent and isolated African American culture, but it did radically influence wider American society. Conversely, CCM failed to break out into mainstream music culture, but it has succeeded in helping to sustain and enrich a vibrant evangelical Christian community. As I argue, the successes and difficulties of BAM and CCM highlight the opportunities and restrictions that exist when labelling any self-conscious arts movement. This is particularly true for the artistic expression in the UK, which is potentially bound together quite inextricably with wider issues of both ethnicity and public religion.

Seafood-borne Vibrio parahaemolyticus illness is a global public health issue facing resource managers and the seafood industry. The recent increase in shellfish-borne illnesses in the Northeast United States has resulted in the application of intensive management practices based on a limited understanding of when and where risks are present. We aim to determine the contribution of factors that affect V. parahaemolyticus concentrations in oysters (Crassostrea virginica) using ten years of surveillance data for environmental and climate conditions in the Great Bay Estuary of New Hampshire from 2007 to 2016. A time series analysis was applied to analyze V. parahaemolyticus concentrations and local environmental predictors and develop predictive models. Whereas many environmental variables correlated with V. parahaemolyticus concentrations, only a few retained significance in capturing trends, seasonality and data variability. The optimal predictive model contained water temperature and pH, photoperiod, and the calendar day of study. The model enabled relatively accurate seasonality-based prediction of V. parahaemolyticus concentrations for 2014–2016 based on the 2007–2013 dataset and captured the increasing trend in extreme values of V. parahaemolyticus concentrations. The developed method enables the informative tracking of V. parahaemolyticus concentrations in coastal ecosystems and presents a useful platform for developing area-specific risk forecasting models.

Seafood-borne Vibrio parahaemolyticus illness is a global public health issue facing resource managers and the seafood industry. The recent increase in shellfish-borne illnesses in the Northeast United States has resulted in the application of intensive management practices based on a limited understanding of when and where risks are present. We aim to determine the contribution of factors that affect V. parahaemolyticus concentrations in oysters (Crassostrea virginica) using ten years of surveillance data for environmental and climate conditions in the Great Bay Estuary of New Hampshire from 2007 to 2016. A time series analysis was applied to analyze V. parahaemolyticus concentrations and local environmental predictors and develop predictive models. Whereas many environmental variables correlated with V. parahaemolyticus concentrations, only a few retained significance in capturing trends, seasonality and data variability. The optimal predictive model contained water temperature and pH, photoperiod, and the calendar day of study. The model enabled relatively accurate seasonality-based prediction of V. parahaemolyticus concentrations for 2014–2016 based on the 2007–2013 dataset and captured the increasing trend in extreme values of V. parahaemolyticus concentrations. The developed method enables the informative tracking of V. parahaemolyticus concentrations in coastal ecosystems and presents a useful platform for developing area-specific risk forecasting models.

This report deals with the active control of heavily damped vibratory mechanical systems in a stochastic environment. The systems of interest are multiple input, multiple output (MIMO)structures that are modeled by generalized complex modes. The control objective is to suppress the effects of impulsive disturbances within a short period of time as well as to provide specified reduction of vibration due to ever-present Gaussian and nonGaussian stochastic disturbances. The team effort, described separately, in this report can be viewed as three interactive parts: one group investigating the robust control issues; one, the nongaussian estimation problem and a third group working with a mechanical plate experiment, generating data and identification algorithms. The experimental model was constructed in the M. E. Department under DARPA funding. The robust control investigators used modern analysis and synthesis tools to incorporate the required performance directly into the design procedure. The approach to handle the nongaussian state estimation problem was in the use of an adaptive Gaussian sum state estimator.

This article describes a comprehensive technique to determine the shapes of GaAs epitaxial layers grown by organometallic chemical vapor deposition (OMCVD) on patterned substrates. A simple technique called the Borgstrom construction, which can predict epitaxial shapes, is reviewed. However, the assumptions in this model limit its applications and the Wulff construction is needed. The Wulff construction can predict edge shapes for constrained and unconstrained (such as at the edge of a mask) epitaxial growth. This technique is valid for any geometric situation assuming the growth rate versus orientation (growth rate polar diagram) is known. A semi-empirical growth rate polar diagram is given for GaAs at 750°C and atmospheric pressure OMCVD. The predictions made by the Wulff construction compare favorably with experimental results. © 1991.

This thesis generalizes the concept of internal feedback loop modeling, due to Tahk and Speyer, to arrive at two new LQG-based methods of parameter robust control. One component of the robustness procedure, common to both methods, is the application of an auxiliary cost functional penalty to desensitize the system to variations in selected parameters of the state-space model. The other component consists of the formulation of a fictitious noise model to accommodate the effect of these parameter variations. The "frequency-domain method" utilizes knowledge of the system dynamics to create a frequency-shaped noise model with a power spectrum that approximates the frequency content of unknown error signals in the system due to parameter uncertainties. This design method requires augmentation of additional dynamics to the plant, which results in higher-dimensional full-order controllers. However, the controller design computations are identical to those of a standard LQG problem. The "time-domain method" emulates the same error signals by means of a multiplicative white noise model which reflects the time-domain behavior of those signals. The resulting robust controller is of the same order as the standard LQG controller, although the design involves a more complex computational algorithm. The application of multiplicative white noise to the system model requires the solution of a system of four coupled equations - two modified Riccati equations and two modified Lyapunov equations. In addition, the optimal projection equations are applied to both robustness methods to reduce the controller order with minimal loss in performance. Comparisons are drawn between these and related robust control methods, and it is shown that the relative effectiveness of such methods is problem dependent. Parameter sensitivity analysis is carried out on a simply supported plate model subject to external disturbances. The appropriate robust controller is selected, and it is found to stabilize

This article describes a comprehensive technique to determine the shapes of GaAs epitaxial layers grown by organometallic chemical vapor deposition (OMCVD) on patterned substrates. A simple technique called the Borgstrom construction, which can predict epitaxial shapes, is reviewed. However, the assumptions in this model limit its applications and the Wulff construction is needed. The Wulff construction can predict edge shapes for constrained and unconstrained (such as at the edge of a mask) epitaxial growth. This technique is valid for any geometric situation assuming the growth rate versus orientation (growth rate polar diagram) is known. A semi-empirical growth rate polar diagram is given for GaAs at 750°C and atmospheric pressure OMCVD. The predictions made by the Wulff construction compare favorably with experimental results. © 1991.

Dry thermal oxidation of GaAs and AlAs has been carried out in an organometallic chemical vapor deposition system. This in situ process performed either before or after an epitaxial growth serves the purposes of surface cleaning and mask generation for selective area epitaxy of various III-V semiconductors. AlAs oxidized immediately after growth and patterned for the next regrowth provides better oxide-semiconductor interfaces and minimizes wafer handling. Pre-epitaxy oxidation at 435°C on a patterned wafer with AlAs/GaAs areas resulted in a selective oxide mask. Since thermal oxides of GaAs sublime at temperatures >600°C, a 700°C pregrowth annealing thus thermally cleans the oxidized GaAs areas while the oxides of AlAs remain as a mask for the following regrowth. Photoluminescence results indicate that high quality regrown interfaces have been obtained.

A study of selective area growth by atmospheric pressure organometallic chemical vapor deposition (OMCVD) using plasma-grown GaAs native oxide masks was conducted. Deposition experiments were carried out with different growth parameters to observe the variation of polycrystalline coverage on the oxide mask. With high growth temperatures or low V/III ratios, poly deposition on the mask was depleted, particularly in regions near the unmasked single-crystal areas. With the optimum conditions for GaAs growth, the polycrystalline growth was homogeneous to the single-crystal boundary, and the single-crystal GaAs areas exhibited liquid nitrogen mobilities up to 105,000 cm**2/Vs.

An analytical method for quantitative interpretation of GaAs photoluminescence spectra was developed. Because of various transition mechanisms the photoluminescence spectrum of a sample may vary significantly under different measurement conditions. Based on a proposed scheme of transition priorities, spectra taken at various excitation powers were analyzed. Comparing results of undoped GaAs epitaxial layers grown by organometallic chemical vapor deposition under similar conditions but different V/III ratios, an optimum ratio corresponding to a minimum number of shallow impurities was clearly identified. Carbon and zinc were found to be the major shallow acceptors in most samples. At very low V/III ratios, carbon was the most dominant acceptor. The carbon concentration diminishes with an increasing ratio and the amount of zinc becomes more significant.

The use of thermal oxides of AlxGa1-xAs (0≤x≤1) as masking materials for selective-area epitaxy by organometallic chemical-vapor deposition has been investigated. It was found that the thermal oxide of GaAs is only applicable for low growth temperatures (≤600°C), and the addition of aluminum significantly improves the thermal stability of the oxide. The oxide of Al0.4Ga0.6As is suitable for high-temperature deposition, but there are criteria for the thickness and oxidation temperature. Thin layers of AlAs oxidized at 475°C are excellent masks and allow precise thickness control. Promising results of selective-area deposition using these aluminum oxide masks have been obtained. High-quality single crystal grew in mask openings uniformly surrounded by dense and fine-grain polycrystalline deposits, producing a planar duplication of the original pattern.

High-quality pseudomorphic GaAs/In0.12Ga0.88As single quantum wells (QW's) were prepared by atmospheric-pressure organometallic chemical vapor deposition. Photoluminesence spectra measured at 2.5 and 78 K exhibit intense, sharp peaks [full width at half-maximum (FWHM)=2.6 meV for a 17-Å well at 78 K] from the quantized energy transitions of the QW's. Peak positions agree well with a square well calculation that includes the strain-induced band-gap shift in the In0.12Ga0.88As. Quite unlike previous work with QW's in which the FWHM was found to exponentially increase with decreasing well width, we observed a narrowing of the QW signals as the well width went below ∼30 Å. In larger well samples (300 Å), the onset of surface crosshatch patterns was observed, which is expected from critical thickness theory.

GaAs and AlGaAs/GaAs multiple quantum wells (MQW) were selectively deposited on GaAs substrates patterned with native oxide, and photoluminescence (PL) characteristics of both the single crystal grown in open windows and the polycrystalline material deposited on the oxide masks were studied. Well-resolved distinct quantum-well (QW) transition peaks indicate no degradation of the epitaxial material quality in the small single-crystal areas. The PL of polycrystalline GaAs is very weak and the peak is centered around the near-band-edge transition energy of GaAs. Polycrystalline MQW structures exhibit much stronger PL signals, and the peak position shifts corresponding to the widths of the QWs grown. These results suggest that the quantum size effect is preserved in the polycrystalline material.

The use of thermal oxides of AlxGa1-xAs (0≤x≤1) as masking materials for selective-area epitaxy by organometallic chemical-vapor deposition has been investigated. It was found that the thermal oxide of GaAs is only applicable for low growth temperatures (≤600°C), and the addition of aluminum significantly improves the thermal stability of the oxide. The oxide of Al0.4Ga0.6As is suitable for high-temperature deposition, but there are criteria for the thickness and oxidation temperature. Thin layers of AlAs oxidized at 475°C are excellent masks and allow precise thickness control. Promising results of selective-area deposition using these aluminum oxide masks have been obtained. High-quality single crystal grew in mask openings uniformly surrounded by dense and fine-grain polycrystalline deposits, producing a planar duplication of the original pattern.

An analytical method for quantitative interpretation of GaAs photoluminescence spectra was developed. Because of various transition mechanisms the photoluminescence spectrum of a sample may vary significantly under different measurement conditions. Based on a proposed scheme of transition priorities, spectra taken at various excitation powers were analyzed. Comparing results of undoped GaAs epitaxial layers grown by organometallic chemical vapor deposition under similar conditions but different V/III ratios, an optimum ratio corresponding to a minimum number of shallow impurities was clearly identified. Carbon and zinc were found to be the major shallow acceptors in most samples. At very low V/III ratios, carbon was the most dominant acceptor. The carbon concentration diminishes with an increasing ratio and the amount of zinc becomes more significant.

Dry thermal oxidation of GaAs and AlAs has been carried out in an organometallic chemical vapor deposition system. This in situ process performed either before or after an epitaxial growth serves the purposes of surface cleaning and mask generation for selective area epitaxy of various III-V semiconductors. AlAs oxidized immediately after growth and patterned for the next regrowth provides better oxide-semiconductor interfaces and minimizes wafer handling. Pre-epitaxy oxidation at 435°C on a patterned wafer with AlAs/GaAs areas resulted in a selective oxide mask. Since thermal oxides of GaAs sublime at temperatures >600°C, a 700°C pregrowth annealing thus thermally cleans the oxidized GaAs areas while the oxides of AlAs remain as a mask for the following regrowth. Photoluminescence results indicate that high quality regrown interfaces have been obtained.

A study of selective area growth by atmospheric pressure organometallic chemical vapor deposition (OMCVD) using plasma-grown GaAs native oxide masks was conducted. Deposition experiments were carried out with different growth parameters to observe the variation of polycrystalline coverage on the oxide mask. With high growth temperatures or low V/III ratios, poly deposition on the mask was depleted, particularly in regions near the unmasked single-crystal areas. With the optimum conditions for GaAs growth, the polycrystalline growth was homogeneous to the single-crystal boundary, and the single-crystal GaAs areas exhibited liquid nitrogen mobilities up to 105,000 cm**2/Vs.

The use of thermal oxides of AlxGa1-xAs (0≤x≤1) as masking materials for selective-area epitaxy by organometallic chemical-vapor deposition has been investigated. It was found that the thermal oxide of GaAs is only applicable for low growth temperatures (≤600°C), and the addition of aluminum significantly improves the thermal stability of the oxide. The oxide of Al0.4Ga0.6As is suitable for high-temperature deposition, but there are criteria for the thickness and oxidation temperature. Thin layers of AlAs oxidized at 475°C are excellent masks and allow precise thickness control. Promising results of selective-area deposition using these aluminum oxide masks have been obtained. High-quality single crystal grew in mask openings uniformly surrounded by dense and fine-grain polycrystalline deposits, producing a planar duplication of the original pattern.

An analytical method for quantitative interpretation of GaAs photoluminescence spectra was developed. Because of various transition mechanisms the photoluminescence spectrum of a sample may vary significantly under different measurement conditions. Based on a proposed scheme of transition priorities, spectra taken at various excitation powers were analyzed. Comparing results of undoped GaAs epitaxial layers grown by organometallic chemical vapor deposition under similar conditions but different V/III ratios, an optimum ratio corresponding to a minimum number of shallow impurities was clearly identified. Carbon and zinc were found to be the major shallow acceptors in most samples. At very low V/III ratios, carbon was the most dominant acceptor. The carbon concentration diminishes with an increasing ratio and the amount of zinc becomes more significant.

High-quality pseudomorphic GaAs/In0.12Ga0.88As single quantum wells (QW's) were prepared by atmospheric-pressure organometallic chemical vapor deposition. Photoluminesence spectra measured at 2.5 and 78 K exhibit intense, sharp peaks [full width at half-maximum (FWHM)=2.6 meV for a 17-Å well at 78 K] from the quantized energy transitions of the QW's. Peak positions agree well with a square well calculation that includes the strain-induced band-gap shift in the In0.12Ga0.88As. Quite unlike previous work with QW's in which the FWHM was found to exponentially increase with decreasing well width, we observed a narrowing of the QW signals as the well width went below ∼30 Å. In larger well samples (300 Å), the onset of surface crosshatch patterns was observed, which is expected from critical thickness theory.

Dry thermal oxidation of GaAs and AlAs has been carried out in an organometallic chemical vapor deposition system. This in situ process performed either before or after an epitaxial growth serves the purposes of surface cleaning and mask generation for selective area epitaxy of various III-V semiconductors. AlAs oxidized immediately after growth and patterned for the next regrowth provides better oxide-semiconductor interfaces and minimizes wafer handling. Pre-epitaxy oxidation at 435°C on a patterned wafer with AlAs/GaAs areas resulted in a selective oxide mask. Since thermal oxides of GaAs sublime at temperatures >600°C, a 700°C pregrowth annealing thus thermally cleans the oxidized GaAs areas while the oxides of AlAs remain as a mask for the following regrowth. Photoluminescence results indicate that high quality regrown interfaces have been obtained.

GaAs and AlGaAs/GaAs multiple quantum wells (MQW) were selectively deposited on GaAs substrates patterned with native oxide, and photoluminescence (PL) characteristics of both the single crystal grown in open windows and the polycrystalline material deposited on the oxide masks were studied. Well-resolved distinct quantum-well (QW) transition peaks indicate no degradation of the epitaxial material quality in the small single-crystal areas. The PL of polycrystalline GaAs is very weak and the peak is centered around the near-band-edge transition energy of GaAs. Polycrystalline MQW structures exhibit much stronger PL signals, and the peak position shifts corresponding to the widths of the QWs grown. These results suggest that the quantum size effect is preserved in the polycrystalline material.