Investigation into the Aerodynamics of Swashplateless Rotors Using CFD-CSD Analysis

This study obtains a better understanding of the aerodynamics of integrated trailing edge flap (TEF) based swashplateless rotors. Both two dimensional (2D) and three dimensional (3D) analysis/simulations are performed to understand the behavior of TEF airfoils and integrated TEF based swashplateless rotors. The 2D aerodynamics of TEF airfoils is explored in detail. A semi-empirical approach is developed for modeling drag for TEF airfoils in steady flows based on baseline airfoil drag data alone. Extensive 2D CFD simulations are performed for a wide range of flow conditions in order to better understand various aspects of the aerodynamics of TEF airfoils. The trends in the airloads (lift, drag, pitching moment, hinge moment) for TEF airfoils are obtained. Nonlinear phenomena such as flow separation, shocks and unsteady vortex shedding are investigated, and the flow conditions and trends associated with them are studied. The effect of airfoil properties such as thickness and overhang are studied. Various approaches are used to model the effect of gaps at the leading edge of the flap. An approximate ``gap averaging'' technique is developed, which provides good predictions of steady airloads at almost the same computational cost as a simulation where the gap is not modeled. Direct modeling of the gap is done by using a patched mesh in the gap region. To solve problems (such as poor grid quality/control and poor convergence) that are associated with the patched mesh simulations, an alternate approach using overlapping meshes is used. It is seen that for TEF airfoils, the presence of gaps adversely affects the effectiveness of the flap. The change in airloads is not negligible, especially at the relatively higher flap deflections associated with swashplateless TEF rotors. Finally, uncoupled and coupled computational fluid/structural dynamics (CFD-CSD) simulations of conventional (baseline) and swashplateless TEF rotors is performed in hovering flight. The CFD-CSD code is validated against experiment and good agreement is observed. It is observed that the baseline UH-60 rotor performs better than the swashplateless UH-60 rotor. For an untwisted NACA0012 airfoil based rotor, the performance is similar for the baseline and swashplateless configurations. The effect of gaps on the performance of swashplateless TEF rotors is also investigated. It is seen that the presence of chordwise gaps significantly affects the effectiveness of the TEF to control the rotor. Spanwise gaps also affect the performance of swashplateless rotors but their effect is not as significant

A Linear Hybrid Sound Generation of Musical Instruments using Temporal and Spectral Shape Features

The generation of a hybrid musical instrument sound using morphing has always been an area of great interest to the music world. The proposed method exploits the temporal and spectral shape features of the sound for this purpose. For an effective morphing the temporal and spectral features are found as they can capture the most perceptually salient dimensions of timbre perception, namely, the attack time and the distribution of spectral energy. A wide variety of sound synthesis algorithms is currently available. Sound synthesis methods have become more computationally efficient. Wave table synthesis is widely adopted by digital sampling instruments or samplers. The Over Lap Add method (OLA) refers to a family of algorithms that produce a signal by properly assembling a number of signal segments. In granular synthesis sound is considered as a sequence with overlaps of elementary acoustic elements called grains. The simplest morph is a cross-fade of amplitudes in the time domain which can be obtained through cross synthesis. A hybrid sound is generated with all these methods to find out which method gives the most linear morph. The result will be evaluated as an error measure which is the difference between the calculated and interpolated features. The extraction of morph in a perceptually pleasant manner is the ultimate requirement of the work. DOI: 10.17762/ijritcc2321-8169.16045

Combination targeted pulmonary hypertension therapy in the resolution of Dasatinib-associated pulmonary arterial hypertension.

Dasatinib is a small-molecule tyrosine kinase inhibitor used in the treatment of hematological malignancies. Pulmonary arterial hypertension (PAH) is a rare but known complication. The mainstay of treatment is cessation of Dasatinib, and while clinical improvement is rapid, complete hemodynamic resolution of pulmonary hypertension (PH) still remains exceedingly uncommon. We present a case of Dasatinib-induced PAH in a woman with chronic myeloid leukemia, who demonstrated rapid and complete clinical and hemodynamic resolution following treatment with combination pulmonary vasodilator therapy using an endothelin receptor antagonist and a phosphodiesterase-5 inhibitor. This case suggests there may be an association between the use of targeted PH medication in combination and the complete resolution of dasatinib-associated PAH, but further investigation is required

Freestyle, a randomized version of ChaCha for resisting offline brute-force and dictionary attacks

This paper introduces Freestyle, a randomized and variable round version of the ChaCha cipher. Freestyle uses the concept of hash based halting condition where a decryption attempt with an incorrect key is likely to take longer time to halt. This makes Freestyle resistant to key-guessing attacks i.e. brute-force and dictionary based attacks. Freestyle demonstrates a novel approach for ciphertext randomization by using random number of rounds for each block, where the exact number of rounds are unknown to the receiver in advance. Freestyle provides the possibility of generating $2^{128}$ different ciphertexts for a given key, nonce, and message; thus resisting key and nonce reuse attacks. Due to its inherent random behavior, Freestyle makes cryptanalysis through known-plaintext, chosen-plaintext, and chosen-ciphertext attacks difficult in practice. On the other hand, Freestyle has costlier cipher initialization process, typically generates 3.125% larger ciphertext, and was found to be 1.6 to 3.2 times slower than ChaCha20. Freestyle is suitable for applications that favor ciphertext randomization and resistance to key-guessing and key reuse attacks over performance and ciphertext size. Freestyle is ideal for applications where ciphertext can be assumed to be in full control of an adversary, and an offline key-guessing attack can be carried out

Intelligent home automation security system based on novel logical sensing and behaviour prediction

The thesis, Intelligent Home Automation Security System Based on Novel Logical Sensing and Behavior Prediction, was designed to enhance authentication, authorization and security in smart home devices and services. The work proposes a three prong defensive strategy each of which are analyzed and evaluated separately to drastically improve security. The Device Fingerprinting techniques proposed, not only improves the existing approaches but also identifies the physical device accessing the home cybernetic and mechatronic systems using device specific and browser specific parameters. The Logical Sensing process analyses home inhabitant actions from a logical stand point and develops sophisticated and novel sensing techniques to identify intrusion attempts to a home’s physical and cyber space. Novel Behavior prediction methodology utilizes Bayesian networks to learn normal user behavior which is later compared to distinguish and identify suspicious user behaviors in the home in a timely manner. The logical sensing, behavior prediction and device fingerprinting techniques proposed were successfully tested, evaluated and verified in an actual home cyber physical system. The algorithms and techniques proposed in the thesis can be easily modified and adapted into many practical applications in Industrial Internet of Things, Industry 4.0 and cyber-physical systems.Thesis (PhD)--University of Pretoria, 2017.Electrical, Electronic and Computer EngineeringPhDUnrestricte

Unsteady Aerodynamic Modeling With Time-Varying Free-Stream Mach Numbers

The development of a reduced-order unsteady airfoil theory is described for application to non-steady, subsonic compressible flows with variable free-stream Mach number. The airfoil theory, which is suitable for application to most types of comprehensive helicopter rotor analyses, is developed for arbitrary, time-dependent combined variations in angle of attack and Mach number. The approach is validated using CFD solutions based on the Euler equations. The new model is developed using the indicial theory as a basis, and shows excellent agreement with direct CFD solutions for a wide range of practical flows. For supercritical flows, nonlinearities associated with the formation and movement of shock waves are observed in the CFD solutions, which the unsteady airfoil theory proves inadequate. Overall, this study shows that the reduced-order unsteady aerodynamic theory provides significant improvements in sectional airloads predictions over existing methods that might be used in various types of comprehensive helicopter rotor analyses

The Harmful Sexual and Non-Sexual Behaviors of Trafficked Women and Children in Mexico: A Study of Victims of Sexual Exploitation

During the last 17 years, since the adoption of the Palermo Protocol, authorities at international and national levels have investigated and prosecuted trafficking cases, and aided victims. Nevertheless, every day thousands of people around the world are sold, lured with false promises and exploited. In Mexico, 10,000 young girls and women are said to be trafficked into cities for sexual exploitation every year. Trafficked victims suffer a wide range of sexual exploitation, physical and psychological violence, human rights violations including their right to dignity, and cruel and inhumane treatment, creating vulnerability and isolation. To cope, many victims adopt harmful sexual and non-sexual behaviors, which we discuss in this paper. For this study, we gathered information from 70 trafficked victims in Monterrey, Mexico. We found that trafficked women and children are forced into high-risk sexual and non-sexual behaviors. Many of them use drugs, alcohol, and marijuana. Their sexual behaviors indicate that many victims are coerced into high-risk sexual practices including having multiple sexual partners