Dr. Ezzat G Bakhoum

A new pressure sensor with ultrahigh sensitivity is presented. The sensor is based on the concept of creating a variable supercapacitor that responds to pressure. The sensor consists mainly of a liquid electrolyte and two graphene aerogel electrodes. As pressure is applied to the graphene aerogel electrodes, the liquid electrolyte penetrates in the pores of the electrodes and a variable supercapacitor is obtained. The sensor is sensitive to pressures of less than 0.1 Pascal. Characteristics of the sensor such as accuracy, nonlinearity, and response time are fully analyzed.

This study investigates the feasibility of utilizing a flow-induced vibration actuator as a potential energy source using piezoelectric energy harvesting. The focus is on exploring the behavior of piezo films configured as cantilever beams subjected to flow-induced vibration, which can be induced with fluid or wind streams. The primary objective is to maximize the harvested energy from the vibrating structure. This paper develops theoretical models to analyze the resonant frequencies and energy-harvesting potential of the piezo films in the context of flow-induced vibration. Experimental validations are conducted to verify the theoretical predictions. The findings indicate that higher operating frequencies in the second mode offer improved energy harvesting efficiency compared with lower modes. With the strategic adjustment of resonant frequencies using attached masses on individual piezo films, the harvestable energy output of a single film can be significantly increased from less than 1 μW to approximately 18 μW. However, the phase differences among individual piezo films can impact frequency measurements, necessitating careful fine-tuning of the physical conditions of individual components. To optimize energy harvesting, this study emphasizes the importance of implementing efficient charging mechanisms. By identifying suitable environmental vibration sources, the required charging duration for a synthesized energy harvesting array can be reduced by 25% as well. Despite certain challenges, such as phase deviations and turbulence, this study demonstrates the promising potential of flow-induced vibration resonators as sustainable energy sources. This work lays the foundation for further advancements in energy harvesting technology, offering environmentally friendly and renewable energy solutions.

Nanoporous gold (NPG) has excellent catalytic activity and has been used in the recent literature on this issue as a sensor in various electrochemical and bioelectrochemical reactions. This paper reports on a new type of metal–oxide–semiconductor field-effect transistor (MOSFET) that utilizes NPG as a gate electrode. Both n-channel and p-channel MOSFETs with NPG gate electrodes have been fabricated. The MOSFETs can be used as sensors and the results of two experiments are reported: the detection of glucose and the detection of carbon monoxide. A detailed comparison of the performance of the new MOSFET to that of the older generation of MOSFETs fitted with zinc oxide gate electrodes is given.

Alpha-particle sources are widely used in industrial and medical applications. Such applications include smoke detectors, static charge eliminators, and radiation therapy. This paper is concerned with the detection of alpha particles. A number of techniques are known for the detection of alpha particles. Those techniques include the Geiger-Muller tube, the ZnS scintillator, the air-filled ionization chamber, and the spark chamber. All the techniques that are currently known are based on the interaction of the ionizing radiation with matter. Charged particles, such as alpha particles, upon entering a medium (such as air), encounter many collisions with bound electrons and lose kinetic energy in the process. The atoms of the medium also become ionized, and a large number of free electrons are released inside the medium. The theory describing the interaction of ionizing radiation with matter is well known and includes formulas such as the Bethe-Bloch formula for the stopping power of matter and formulas for calculating the range of the ionizing radiation in matter. Essentially, all the known techniques for the detection of alpha particles are based on detecting the presence of free electrons inside the medium. This paper presents a new technique for the detection of alpha particles that does not depend on the theory of the interaction of alpha particles with matter. Instead, the technique is based on the direct detection of the positive charge that is carried by the alpha particles. Furthermore, it is the objective of this paper to demonstrate that the direct detection of the charge carried by alpha particles can be done with a tiny and inexpensive component: a metal-oxide-semiconductor field-effect transistor (MOSFET).

This paper introduces a new angular position sensor that measures 3 mm (diameter) by 0.5 mm (thickness); and it is therefore a MEMS scale sensor. The sensor's operating principle is variable capacitance; however, unlike ordinary variable capacitance transducers, the new sensor is based on the concept of creating a variable Ultracapacitor (or Supercapacitor). One degree of rotation in the present sensor results in a capacitance variation of 1.5 ~\mu \text{F} , which is very substantial by comparison with other types of variable capacitance transducers of the same dimensions. The sensitivity of this new sensor is therefore substantially high. It will be suitable for applications that require a MEMS-scale transducer and high sensitivity. [2021-0168]

In the recent years, robotic devices have been widely used to interact with human beings in various scenarios, including healthcare, education, tourism, and manufacturing applications. These applications of robotic devices have also been expanded to many social activities. These social robots can take the form of a traditional mobile robot or a humanoid system that provide one-on-one interaction. Among different types of robotic devices, the bio-inspired humanoid robotics has received extensive attention in therapeutic settings by providing psychological and physiological benefits. With the social benefits, humanoid type of social robots can be an important tool to assist people in many different situations.
To allow social robotic devices to better interact with human being, it is desired that these robotic systems can identify ongoing human motions and respond to the motions by mimicking human movements. Thus, these systems need to acquire human motions and predict the types of these movements in real-time. Such a technique has been investigated by various research groups. Once the human motions have been identified, corresponding reactions of the robots can be determined accordingly, which usually requires the involved joints to move along specific trajectories. To synthesize such an interactive robotic system, a platform of a multi-axial robotic device, a motion identification model of human motions, a reference generator based on the identified motions, the sensors used for real-time motion measurements, and an adequate control strategy need to be integrated as a single system. The major bottleneck of such a system is that the processing and control units might not be efficient enough and can cause dramatic legacy. To validate the overall process, a simplified system was developed to investigate the feasibility of such an interactive robotic system.
In this study, an experimental multi-axial robotic arm was adopted. A developed motion identification model was used to determine the on-going motions of the interacting person. Once the motion being identified, the responding motion of robotic device can be determined based on a pre-selected motion library. The trajectories of individual joints of the robotic arm can then also be generated accordingly. The robotic arm was then following the pre-selected trajectories for corresponding interactions. To compensate for the nonlinear factors caused by existing mechanical/electrical components and the cross-coupled dynamics among the mechanical components, a control strategy that integrates an adaptive robust control method and a linear controller for motion tracking was applied. With the proposed control scheme, an adequate controlled outcome can be achieved.

In this paper, we propose to design, develop, and study a cyber-physical system that enables patients and therapists to virtually interact for rehabilitation activities with assistive robotic devices. The targeted users of this system are post stroke patients. On the patient's side, an assistive robotic device can generate the force that the therapist applies to the patient. On the therapist's side, another robotic device can reproduce the responsive force generated by the patient. With this system, the interaction can be virtually established. In addition, by integrating real human trajectories, the proposed assistive robotic system can help patients to perform rehabilitation activities in their own pace. Such an assistive robotic system and virtual interacting scheme can minimize both patient's and therapist's traveling time. The assistive functions of this light weight design can also help patients to in their ADLs.