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]

This paper introduces a miniature, 3-axis, acceleration sensor with extremely high sensitivity. The sensor is of the variable capacitance type. However, instead of using a conventional variable capacitor configuration, the sensor is based on a variable ultracapacitor (or supercapacitor). A very small droplet of electrolyte is positioned in between six electrodes that are arranged in the form of a cube. The inner surfaces of the electrodes are coated with carbon nanotubes (CNTs), and hence a variable ultracapacitor exists between any two of the six electrodes. Acceleration forces the electrolyte droplet to move in different directions and take different shapes, thereby altering the capacitance between any two given electrodes in the device. The prototype described in this paper has shown an inter-electrode capacitance variation of 7.5 \mu \text{F} under an acceleration increase from 0 to 100 g. The sensitivity is therefore 75 nF/g.

This paper introduces a novel technique for the detection of meat spoilage. While highly accurate and reliable, the technique is a low-cost technique, and is, therefore, easily within the reach of consumers and retailers. The technique is based on the principle of detecting volatile organic compounds (VOCs) that are released during the meat decomposition by means of certain chemically sensitive dyes. A group of chemically sensitive dyes are printed on paper in the form of a bar code. The bar code is then inserted inside the meat packaging. When exposed to VOCs, the dyes change their colors. A cheap handheld instrument is subsequently used to scan the bar code and instantly apply pattern recognition techniques to detect variations in the colors of the dyes. The instrument reports the condition of spoilage of the product within a fraction of a second.

This paper introduces a novel technique for repairing defective soldering joints in densely packed printed circuit boards and multichip modules. The new technique is not based on conventional soldering methods or tools, but rather on the remarkable properties of gold nanoparticles. Gold nanoparticles are deposited on the surface of the solder pad or joint that must be reworked, and a low-power laser with a wavelength in the range of 500-800 nm is directed to the area where the gold nanoparticles are present. The nanoparticles absorb the electromagnetic radiation at such wavelengths very effectively, and intense surface plasmons are generated in the nanoparticles. The surface plasmons cause the nanoparticles to heat up, where the temperature can reach several hundred degrees of Celsius. This in turn causes the solder that is in contact with the nanoparticles to melt, while other solder joints in the vicinity remain unaffected. The narrow wavelength range of 540-572 was determined to be the optimal range of wavelengths for the present application.