Study of soft materials, flexible electronics, and machine learning for fully portable and wireless brain-machine interfaces

Over 300,000 individuals in the United States are afflicted with some form of limited motor function from brainstem or spinal-cord related injury resulting in quadriplegia or some form of locked-in syndrome. Conventional brain-machine interfaces used to allow for communication or movement require heavy, rigid components, uncomfortable headgear, excessive numbers of electrodes, and bulky electronics with long wires that result in greater data artifacts and generally inadequate performance. Wireless, wearable electroencephalograms, along with dry non-invasive electrodes can be utilized to allow recording of brain activity on a mobile subject to allow for unrestricted movement. Additionally, multilayer microfabricated flexible circuits, when combined with a soft materials platform allows for imperceptible wearable data acquisition electronics for long term recording. This dissertation aims to introduce new electronics and training paradigms for brain-machine interfaces to provide remedies in the form of communication and movement for these individuals. Here, training is optimized by generating a virtual environment from which a subject can achieve immersion using a VR headset in order to train and familiarize with the system. Advances in hardware and implementation of convolutional neural networks allow for rapid classification and low-latency target control. Integration of materials, mechanics, circuit and electrode design results in an optimized brain-machine interface allowing for rehabilitation and overall improved quality of life.Ph.D

NP domino logic gates for Ultra Low Voltage and High Speed applications

In this thesis we present different configurations of digital circuits exploiting Ultra Low Voltage (ULV) NP domino logic style. The proposed logic style is utilized with the help of Floating gate transistors. The proposed NP domino logic gates are aimed to perform high speed operations in Ultra Low Voltage applications. The presented circuits may operate near the sub-threshold regime where the supply voltage is near the threshold voltage of the transistors. In terms of frequency, speed, robustness, Power Delay Product (PDP) and Energy Delay Product (EDP), the proposed ULV NP domino logic gates may offer significant improvement compared to the conventional CMOS logic gates. Different implementations of NOT, NAND and NOR gates are presented using both conventional and Pass Transistor Logic styles. Further, NAND and NOR gates are used to employ different configurations of Carry gates which is a speed limited factor in many arithmetic operations. These ULV NP domino Carry gates are simulated at different supply voltages in the range of 100mV to 400mV, and the performance results are presented with respect to delay, power, PDP and EDP. The proposed ULV NP domino Carry gates are cascaded together to perform addition in a 32-bit chain. The circuits are operated with respect to worst case scenario where the carry signal propagates through the whole chain. Multi-threshold (MTCMOS) and Variable-threshold (VTCMOS) techniques are employed in the ULV domino 32-bit carry chain in order to reduce the power consumption, meanwhile offering superb speed performance. Although the 32-bit carry chain offers a great advantage of speed improvement in the worst case scenario, the chain also introduces the drawback of enormous power consumption in the idle mode. The work in this thesis has resulted in three papers. Two of these papers represent various configurations of 1-bit ULV NP domino Carry gates, while the third paper examines the performance of one of the proposed ULV NP domino Carry gates in a 32-bit chain. The simulation results presented in this thesis are obtained using a 90nm TSMC CMOS process

Investigation in Gas-Oil Two-Phase Flow using a Differential Pressure Transducer and Wire Mesh Sensor in Vertical Pipes

The current study is performed to identify the flow regimes of oil-gas two-phase flow experimentally in a vertical pipe has an internal diameter of 6.7 cm. It also aims to provide more details about the possibility of using Differential Pressure Transducers (DPT) for indicating flow patterns. A flow development of oil and gas has been investigated in a vertical pipe of 6 m in length and operated at atmospheric pressure. A series of experiments have been run to cover a range of inlet oil superficial velocities from 0.262 to 0.419 m/s, and inlet gas superficial velocities from 0.05 to 4.7 m/s. Wire Mesh Sensors (WMS) have been used to collect the obtained void fraction values of the flow. The Differential Pressure Transducer (DPT) is utilized to measure the pressure drop values of a one-meter along the pipe. The flow patterns are classified according to the analysis of void fractions, pressure gradients regarding time series, tomographic images, probability density functions of the void fractions, and pressure gradients. A bubbly flow is observed at low superficial velocities of gas and liquid, slug flow is observed at the lower flow rate of liquid and moderate flow rates of gas, while the churn flow pattern is recognized at the higher rates of liquid and gas. Also, the result has revealed the possibility of using Differential Pressure Transducers (DPT) to classify the gas-oil flow patterns in vertical pipes

Traversing the Waste Spectrum: Unveiling Pakistan's MSW Landscape and Solutions

Municipal solid waste (MSW) management must be sustainable in order to meet the Sustainable Development Goals (SDGs) and address health, environmental, and disposal challenges caused by the vast amounts of trash generated. MSW management going wrong puts locals in danger. In Pakistan, the production of municipal solid trash is rising daily. Urban settlers and other organizations gather a lot of waste in various forms, usually defiling and making our surroundings uninviting.  Due to the indiscriminate dumping of various wastes, the soil quality in the metropolitan area has decreased as a result of solid and liquefied waste disposal. Significant environmental concerns regarding soil and water pollution arise from transferring contaminated garbage and mixed fluid outside of waste disposal borders. The impacts of municipal garbage disposal on soil and water quality at open waste dumping sites were the main focus of this review. Using a soil and water quality index, in many regions of the world especially in regions where waste management practices are insufficient, the contamination of soil and water owing to incorrect municipal solid waste disposal is a serious environmental hazard. Open dumping, unregulated landfilling, and illegal dumping are examples of improper waste disposal practices that can result in pollution that affects the quality of the soil and water. They must also seek to identify sustainable waste management solutions. The effect of these emitted gaseous emissions has, however, been thoroughly researched. To safeguard the environment and public health, quick action must be made to control trace element pollution

Karyological studies of four agamid lizards from Semnane province of Iran

Iran possesses about 241 species of reptiles, which 55 species of them (22.8%) are endemic to Iran. Agamidae is the important family of reptile in Iran with 22 species, which is poor in terms of chromosomal studies. In this paper, karyological survey was made for four species of the family Agamidae by bone marrow cell preparations. Karyotype of male and female of Laudakia caucasia (2n=34) was consisted of 6 pairs macro and 11pairs of microchromosomrs. Karyotype of Laudakia nupta nupta (2n=36) was including of 6 pairs of macro and 12 pairs of microchromosomes. Karyotype of Phrynocephalus scutellatus (2n=46) was consisted of 22 macro and 24 microchromosomes, which is reported here for the first time. Also, new cytotype of Traplus agilis agilis (2n=49) is reported here for the first time. Karyotype of this species was consisted of 21 large acrocentric and 28 microchromosomes, which one of the acrocentric chromosomes may be a sex chromosome

Fully portable and wireless universal brain-machine interfaces enabled by flexible scalp electronics and deep-learning algorithm

Variation in human brains creates difficulty in implementing electroencephalography (EEG) into universal brain-machine interfaces (BMI). Conventional EEG systems typically suffer from motion artifacts, extensive preparation time, and bulky equipment, while existing EEG classification methods require training on a per-subject or per-session basis. Here, we introduce a fully portable, wireless, flexible scalp electronic system, incorporating a set of dry electrodes and flexible membrane circuit. Time domain analysis using convolutional neural networks allows for an accurate, real-time classification of steady-state visually evoked potentials on the occipital lobe. Simultaneous comparison of EEG signals with two commercial systems captures the improved performance of the flexible electronics with significant reduction of noise and electromagnetic interference. The two-channel scalp electronic system achieves a high information transfer rate (122.1 ± 3.53 bits per minute) with six human subjects, allowing for a wireless, real-time, universal EEG classification for an electronic wheelchair, motorized vehicle, and keyboard-less presentation

Experimental Investigation of Two-Phase Flow Patterns in a Vertical to Horizontal Bend Pipe Using Wire-Mesh Sensor

The air-water two-phase flow plays an important role in many applications of industry fields. Usually, a 90-degree bend is used to connect pipes for changing the direction of flow which influences the two-phase flow pattern. In this paper, the effect of 90-degree bend under different ranges of gas and liquid superficial velocities on the two-phase flow patterns in the horizontal pipe located after the bend was experimentally investigated, and then results were presented and compared in a two-phase flow pattern map. Also, tomographic images and probability density functions were used to capture the cross- section void fraction and its distribution for the two-phase flow patterns. The results revealed that at low liquid and gas flow rates, a stratified-wavy flow pattern was observed as a dominant flow pattern. While the wavy-annular and semiannular flow patterns were observed at a high range of gas flow rates in the horizontal pipe. The results also showed that at the high range of liquid flow rate, bubbly, plug, slug, stratified-wavy, and wavy-annular flow patterns were observed in the horizontal pipe when the gas flow increased. The tomographic images and probability density functions gave good agreement with the experimental observations and results

Structural, electronic, optical, and thermoelectric properties of beta phase spinel : prospects for solar cells application

Using all electron based density functional theory calculations, within full potential linearized augmented plane wave plus local orbitals, electronic, structural, optical and thermoelectric properties of the β-phase spinel compound have been investigated. Tetragonal β-phase spinel indium (III) sulfide is the most stable and promising phase for various applications, in particular, photovoltaic devices, and, therefore, it can be use to replace CdS for environmental issues. The unit cell volume and atomic positions are optimized with the PBE energy functional and our calculated optical band gap for the indirect transition is in good agreement with the experimental value. The peaks of the real part of optical conductivity σ(ω) correspond to the peak of the imaginary part of dielectric function εi (ω) for the two polarization axes, which perfectly agree with the Drude theory. Charge carrier concentration are observed to attain the maximum value at about 2.8899 eV at fixed temperature, and drops at high energies, which indicates less photon excitation to the conduction bands at energies greater than 2.8899 eV. The electrical and thermal conductivity that depends on the sulfur concentration show a similar trend for variable and fixed temperature. Large amount of thermopower S occurs at low temperature, which agrees with the requirement to improve performance of photovoltaic materials, that is high voltage output at small amount of hea

Integrating mobile game application in enhancing students' willingness to communicate in English

English is an important communication medium for Malaysians, particularly in higher education and business. As a result, substantial effort has been invested in producing students who can communicate effectively in a variety of social and professional settings. It is believed that, as a result of the new learning standard, mobile game applications offer a greater opportunity to enhance language learning, particularly English, for Gen-Z students. One of the mobile gaming applications utilised for this study was Languinis, an original, free word puzzle mobile game. An administered questionnaire was administered to 120 ESL students as part of a mixed-methods approach. A semi-structured interview with 10 ESL students was also conducted. The data of the investigation revealed that few pupils are familiar with the Languinis word game. Nonetheless, the finding also revealed that the students enjoyed using the mobile game application to improve their vocabulary, which they then utilised in their spoken interactions. As a result, their Willingness to Communicate (WTC) in English has improved