Multi-Objective Gust Load Alleviation Control Designs for an Aeroelastic Wind Tunnel Demonstration Wing

This paper presents several control and gust disturbance estimation techniques applied to a mathematical model of a physical flexible wing wind tunnel model used in ongoing tests at the University of Washington Aeronautical Laboratory's Kirsten Wind Tunnel. Three methods of gust disturbance estimation are presented, followed by three control methods: LQG, Basic Multi-Objective (BMO), and a novel Multi-Objective Prediction Correction (MOPC) controller. The latter of which augments a multi-objective controller, and attempts to correct for errors in the disturbance estimate. A simplified linear simulation of the three controllers is performed and a simple MIMO stability and robustness assessment is performed. Then, the same controllers are simulated in a higher fidelity Simulink environment that captures sampling, saturation and noise effects. This preliminary analysis indicates that the BMO controller provides the best performance and largest stability margins

Dental Treatment Approach in Cantho University of Medicine and Pharmacy of Vietnam

The traditional morphological concept to dental care has shown many drawbacks and is not appropriate in many cases. To counteract these shortcomings, a problem-solving approach has been introduced in dental curriculum of Cantho University of Medicine and Pharmacy (CTUMP), Vietnam. This approach should be reflected in dental practice in CTUMP. Objective: To investigate the problem-solving approach to dental care of CTUMP by patterns of tooth extraction, and tooth rehabilitation. Methods: Cross-sectional data on DMF, dental treatments planned, dental treatments delivered from 1549 dental records of patients aged ≥18 of CTUMP were analyzed. Results: The majority of patients were aged 18-29 (929, 60%), classified as professional and skilled workers (1112 subjects, 72%), lived in urban areas (1156 subjects, 75%), and women (932, 60%). The number of teeth eventually receiving dental treatment was lower than the number of teeth indicated for the treatment. On average, each patient had 2 teeth receiving treatment. Tooth restoration was the most common treatment (1390, 70%). Molars were the most treated teeth (842, 43%). Molars showed statistically significant higher chance for restoration and extraction than premolars and anterior teeth (Wilcoxon-signed-ranks test p ≤ 0.017). No statistically significance was found in tooth replacement between premolar and molar regions. The dental treatments aimed to preserve all teeth regardless of dental regions. Tooth replacement may tend to be morphologically based rather than functionally as most prostheses restored the complete dental arch. Conclusions: The approach to dental care in CTUMP tends to be morphologically conservative.DOI: 10.14693/jdi.v22i1.37

A molecular simulation study of thermal and pH effects on apo-lactoferrin stability: implications for potential encapsulation function of gram-positive bacteria

In this Masters thesis computational modelling techniques were employed to investigate iron-free apo-Lactoferrin (apo-Lf) structural conformation changes in the presence of variant temperature and pH. These conditions represent the environment most milk protein goes through in food processing and the production of food products. Lactoferrin (Lf) is an iron-binding glycoprotein present in secretory fluids of nasal, pancreatic, amniotic, seminal plasma, saliva and tears, and in milk secretions such as those from human and bovine sources. It is reported to have multifunctional roles such as antibacterial, antivirus, antifungal, anti-inflammatory and anticancer activities. In order to explore apo-Lf’s potential as an encapsulant for probiotics, sequence alignment was employed to identify a region on the C-lobe of Lf capable of binding to bacterial cell surfaces, followed by all-atom explicit solvent molecular dynamics (MD) simulations which were applied to study the conformational changes of apo-Lf after exposure to three processing temperatures: pasteurization (72 °C), spray drying (90 °C) and close to ultra-high temperature (UHT) (135 °C) in a pH 7.0 environment. Below 90 °C, the simulations indicate relatively minor changes in overall protein structure, dimensions, per-residue fluctuations and inter-residue contacts and motional correlations, relative to a low temperature (27 °C) control simulation, consistent with experimentally-known conservation of apo-Lf structure and properties at low thermal processing temperatures. At conditions similar to UHT (127 °C), however, marked disruptions to protein structure are predicted to occur at a number of levels. There was a substantial decrease in protein dimensions due to collapse in the inter-lobe region, causing a reduction in separation between the N- and C-terminal lobes. The α-helical content was reduced, although much of the β-pleated sheet structure was retained. There was a marked increase in residue fluctuations in several regions of known functional importance, including the antibacterial and iron-binding regions, as well as a C-terminal area predicted to play a role in bacterial membrane surface binding. It is proposed that this putative membrane binding region was stabilized by a triplet of hydrophobic residues comprised of Leu446, Trp448 and Leu451, and that their mutual interactions are severed at 400 K, resulting in changes to the structure, and potential membrane binding propensity, of this region. Network analysis of disruptions to inter-residue contacts also identified large clusters of residues in the N-terminal lobe which lose contacts with their neighbours. Taken together, UHT conditions are therefore predicted to cause disruptions to multiple functional properties of apo-Lf. Furthermore, a unique method was proposed for identifying thermal-induced protein unfolding based on examining the topology of networks of inter-residue motional correlation gain for high-temperature simulation trajectories relative to a low-temperature control simulation. To further explore apo-Lf’s potential as an encapsulant for Gram-positive bacteria, MD simulations along with examining topology networks were applied again to study the pH-induced protein unfolding of apo-Lf after the exposure of pH conditions potentially experienced by the protein in the course of its lifetime as a food component product, from processing to consumption. This was achieved by studying the effects of “extreme” acidic (nominally pH 1.0) and basic (nominally pH 14.0) conditions on apo- Lf relative to neutral pH 7.0. These simulations predicted that pH 1.0 conditions affected parts of the N-Lobe, the lobe where the antibacterial peptides are located, while the pH 14.0 conditions affected the C-Lobe, the lobe in which the identified Gram-positive bacteria binding peptide is found. Overall, the MD simulation studies of apo-Lf, showed protein structural deviations which might have implications for the temperature- and pH-dependent properties of the bacterial cell binding regionsidentified in apo-Lf. By enabling the thermal and pH sensitivity of several regions of functional importance to be identified, the results of these simulations can be used to further assist in the prediction of conditions suitable for successful protection and encapsulation of lactic acid bacteria using bovine milk protein materials such as lactoferrin. The outcome of this thesis can benefit the functional food and pharmaceutical industry by offering an alternative encapsulation material

Time-varying Weights in Multi-Objective Optimal Control for Flexible Wing Aircraft

A multi-objective optimal control technique is modified to accommodate changing cost function weights and is used to control a flexible wing aircraft model. Variation of the weights is used to adjust the relative importance of each objective according to either a prescribed function of time or of the state. Several techniques for obtaining a practical approximation to the optimal control solution are presented, and stability of a specific weight structure with the optimal controller is demonstrated. Functionality of the multi-objective control design with weight variation is demonstrated in simulation of a flexible wing transport aircraft and is shown to improve performance over the fixed weight version both at a constant flight condition and across changing flight conditions

Aerodynamic Modeling of Transonic Aircraft Using Vortex Lattice Coupled with Transonic Small Disturbance for Conceptual Design

The need to rapidly scan large design spaces during conceptual design calls for computationally inexpensive tools such as the vortex lattice method (VLM). Although some VLM tools, such as Vorview have been extended to model fully-supersonic flow, VLM solutions are typically limited to inviscid, subcritical flow regimes. Many transport aircraft operate at transonic speeds, which limits the applicability of VLM for such applications. This paper presents a novel approach to correct three-dimensional VLM through coupling of two-dimensional transonic small disturbance (TSD) solutions along the span of an aircraft wing in order to accurately predict transonic aerodynamic loading and wave drag for transport aircraft. The approach is extended to predict flow separation and capture the attenuation of aerodynamic forces due to boundary layer viscosity by coupling the TSD solver with an integral boundary layer (IBL) model. The modeling framework is applied to the NASA General Transport Model (GTM) integrated with a novel control surface known as the Variable Camber Continuous Trailing Edge Flap (VCCTEF)

Multi-Objective Optimal Control of the 6-DoF Aeroservoelastic Common Research Model with Aspect Ratio 13.5 Wing

A new 6-DoF aeroservoelastic (ASE) Common Research Model (CRM) provided by The Boeing Company with aspect ratio 13.5 and 17 control surfaces per wing is utilized to demonstrate combined tracking and optimal multi-objective control. The multi-objective controller is derived on the closed loop tracking controller, and utilizes state and gust estimates provided by an extended state observer. Various methods of model reduction useful for control and estimation are presented. A computationally efficient MATLAB/Simulink simulation is presented which includes actuator dynamics, rate and deflection saturation limits, and gust disturbance inputs. The platform is used to demonstrate excellent 6-DoF tracking control performance coupled with the multi-objective controller, which is shown to effectively reduce structural mode movement, wing root bending moment, and drag. State and gust estimation is also shown to perform well, even when derived and/or implemented with significantly fewer states than the original full-sized model

Brain function early after stroke in relation to subsequent recovery.

This study aimed to characterize brain activation and perfusion early after stroke within cortical regions that would later change activation during recovery. Patients were studied serially after stroke (mean t1, = 16 days after stroke, t2 = 3.5 months later) using perfusion-weighted imaging and functional magnetic resonance imaging during finger movement. Controls (n = 7) showed no significant change in regional activation volumes over time. Among stroke patients (n = 8), however, recovery was accompanied by several patterns of functional magnetic resonance imaging change, with increased activation volumes over time in five patients and decreased in two. Most regions increasing activation over time were in the stroke hemisphere. Of the five patients showing increased activation over time, specific activation foci enlarged at t2 were already activated at t1 in four patients, and at least one focus growing from t1 to t2 was in a different arterial distribution from the infarct in all five patients. Perfusion of sensorimotor cortex at t1 was generally not reduced in the stroke hemisphere (94% of noninfarcted hemisphere). Improved clinical outcome was related to increased activation within sensory cortices of both brain sides, including bilateral secondary somatosensory areas. Early after stroke, cortical activation that will later increase in parallel with recovery is often already identifiable, can be remote from the vascular territory of the infarct, and is not likely hindered by reduced perfusion. The findings may be useful for restorative interventions introduced during the weeks after a stroke

The CP43 Proximal Antenna Complex of Higher Plant Photosystem II Revisited: Modeling and Hole Burning Study. I

The final version is available at: http://pubs.acs.org/journal/jpcbfkThe CP43 core antenna complex of photosystem II is known to possess two quasi-degenerate “red”-trap states (Jankowiak, R. et al. J. Phys. Chem. B 2000, 104, 11805). It has been suggested recently ( Zazubovich, V.; Jankowiak, R. J. Lumin. 2007, 127, 245) that the site distribution functions of the red states (A and B) are uncorrelated and that narrow holes are burned in the subpopulations of chlorophylls (Chls) from states A and B that are the lowest-energy Chl in their complex and previously thought not to transfer energy. This model of uncorrelated excitation energy transfer (EET) between the quasidegenerate bands is expanded by taking into account both electron−phonon and vibrational coupling. The model is applied to fit simultaneously absorption, emission, zero-phonon action, and transient hole burned (HB) spectra obtained for the CP43 complex with minimized contribution from aggregation. It is demonstrated that the above listed spectra can be well-fitted using the uncorrelated EET model, providing strong evidence for the existence of efficient energy transfer between the two lowest energy states, A and B (either from A to B or from B to A), in CP43. Possible candidate Chls for the low-energy A and B states are discussed, providing a link between CP43 structure and spectroscopy. Finally, we propose that persistent holes originate from regular NPHB accompanied by the redistribution of oscillator strength due to excitonic interactions, rather than photoconversion involving Chl−protein hydrogen bonding, as suggested before (Hughes J. L. et al. Biochemistry 2006, 45, 12345). In the accompanying paper ( Reppert, M.; Zazubovich, V.; Dang, N. C.; Seibert, M.; Jankowiak, R. J. Phys. Chem. B 2008, 9934), it is demonstrated that the model discussed in this manuscript is consistent with excitonic calculations, which also provide very good fits to both transient and persistent HB spectra obtained under non-line-narrowing conditions.This work was supported by the start-up funding at the Department of Chemistry, Kansas State University (RJ, NCD, MR and BN), and in part by the U.S. Department of Energy (DOE) EPSCoR grant (RJ), Energy Biosciences Program, Basic Energy Sciences, DOE (MS and NCD) and BFU2005-07422-CO2-01; Spain (RP). VZ acknowledges support by NSERC.Peer reviewe

Barriers to the adoption of renewable and energy-efficient technologies in the Vietnamese power sector

This paper examines the major barriers to the deployment of geothermal, small hydro and advanced coal power generation technologies in Vietnam. It ranks their severity by applying the analytical hierarchy process to data from a survey of 37 domestic experts and stakeholders. Key barriers to a wider penetration of small hydro generation technologies are insufficient capital, a lack of domestic suppliers and unsatisfactory government policies. Barriers to geothermal power are related to information and awareness problems, a lack of R&D and industrial capability, a weak policy framework and the remoteness of geothermal sites. For advanced coal power technologies, the barriers are weak industrial capability, high cost and a lack of technical knowledge. The experts consulted in this study view changes in government actions as the key to overcoming the abovementioned barriers. They recommend investing more in R&D activities, improving R&D capacity through joint-venture schemes and reforming investment policy/legislation for the electric power industry as the most appropriate solutions.analytical hierarchy process; renewables; energy efficient technologies.