Papers by Mohamed A Ibrahim
Background: Implant soft tissue dehiscence is a frequently reported esthetic complication, that m... more Background: Implant soft tissue dehiscence is a frequently reported esthetic complication, that more often than not affects the functional integrity of the dental implant with eventual loss of osteointegration. Many treatment modalities with different success rates have been proposed aiming to solve this complication or prolong the survival of the dental implant, of which are guided bone regeneration and soft tissue regeneration around the affected implants. Material and Methods: This prospective study was carried in the hospital of Future University. 11 Patients (1 Male – 10 Females) with 20 Maxillary implant sites demonstrating soft tissue dehiscence were randomly allocated to either a guided bone regeneration (GBR) group (Control) in which patients received a mixture of autogenous and xenogeneic bone graft substitute covered by a native collagen membrane fixated with titanium tacks over the affected implants or a connective tissue graft and coronal flap advancement (CTG + CAF) gr...
2019 Joint Conference of the IEEE International Frequency Control Symposium and European Frequency and Time Forum (EFTF/IFC), 2019
The conceptual design and measurement of a monolithic bulk acoustic wave (BAW) oscillator with co... more The conceptual design and measurement of a monolithic bulk acoustic wave (BAW) oscillator with conventional plastic QFN packaging is presented. The unique Silterra technology allows the integration of high frequency BAW resonators on top of a standard 0.13µm CMOS technology [1]. The oscillator circuitry is placed under the BAW resonator for smaller form factor and reduction of parasitics. The oscillator has tunable gain and phase and the output signal can be divided by a factor from 8 to 240. The measured phase noise performance of the 2.22GHz oscillator is -85dBc/Hz at 10 kHz offset frequency and a -158dBc/Hz noise floor. The integrated phase jitter from 12 kHz to 20 MHz is $< 360$ fs. This low noise oscillator allows the development of high performance and high frequency signal sources based on MEMS BAW oscillators replacing the traditional LC CMOS solutions.
Electronics, 2021
In this article, we present a new photocurrent sensory circuit with a three-transistor background... more In this article, we present a new photocurrent sensory circuit with a three-transistor background light cancellation. We describe our innovative photocurrent sensor-based blood pressure measuring device using a resistor-based current-to-voltage converter with a background light cancellation (BLC) loop. The photocurrent sensor is implemented using 0.35 μm standard CMOS technology and has zero average power consumption. The post-layout simulation for the photocurrent sensor shows a 1.3 MΩ transimpedance gain, a referred input noise current of 11 pA, and can reject a DC photocurrent up to 200 μA. This high DC rejection has been achieved due to the newly proposed multi-transistor BLC loop integrated with the sensor.
Sensors, 2019
A low-power, high-gain, and low-noise analog front-end (AFE) for wearable photoplethysmography (P... more A low-power, high-gain, and low-noise analog front-end (AFE) for wearable photoplethysmography (PPG) acquisition systems is designed and fabricated in a 0.35 μm CMOS process. A high transimpedance gain of 142 dBΩ and a low input-referred noise of only 64.2 pArms was achieved. A Sub-Hz filter was integrated using a pseudo resistor, resulting in a small silicon area. To mitigate the saturation problem caused by background light (BGL), a BGL cancellation loop and a new simple automatic gain control block are used to enhance the dynamic range and improve the linearity of the AFE. The measurement results show that a DC photocurrent component up-to-10 μA can be rejected and the PPG output swing can reach 1.42 Vpp at THD < 1%. The chip consumes a total power of 14.85 μW using a single 3.3-V power supply. In this work, the small area and efficiently integrated blocks were used to implement the PPG AFE and the silicon area is minimized to 0.8 mm × 0.8 mm.
Clinical Implant Dentistry and Related Research, 2021
ObjectiveCompare the dimensional changes of the peri‐implant soft and hard tissues clinically and... more ObjectiveCompare the dimensional changes of the peri‐implant soft and hard tissues clinically and radiographically around single immediate implants in the esthetic zone with socket shield technique versus filling the buccal gap with xenograft.Materials and methodsForty‐two patients with a single non‐restorable tooth in the esthetic zone replaced with an immediate implant were randomly assigned either to the socket shield technique (test) or to grafting the buccal gap with xenograft (control). The vertical and horizontal buccal bone resorption were measured 6‐months following implant placement. The esthetic outcomes were evaluated by assessing the Pink Esthetic Score (PES) and the amount of midfacial mucosal alteration, in addition to patient satisfaction assessment through a Visual Analogue Scale (VAS) based questionnaire 1‐year following implant restoration.ResultsThe present study showed that the socket shield group yielded significantly less vertical and horizontal buccal bone re...
Journal of the Mechanical Behavior of Materials, 2021
Egypt plays an important role in the consuming markets for tires all over the world. There is an ... more Egypt plays an important role in the consuming markets for tires all over the world. There is an urgent need to get rid of them in an economic and environmental way since it is considered as a harmful waste if burnt. The World trend is directed towards the improvement of new techniques to insert the rubber into useful products to maximize the benefit of recycling. This research deals with the expansion of novel techniques for rubber powder recycling for various purposes in a robust construction. Recycled rubber particles (RRP) are mixed with ordinary Portland cement (OPC) using various water to binder ratio (W/B) at 0.3 and 0.4. The Fourier transform – infrared (FT-IR) spectra is measured for RRP. The compressive strength (C.S) is investigated for the rubberized cement pastes at 1, 3, 7, 14 and 28 days. The results aimed to enhance the compressive strength of rubberized cement pastes through improving the bonding strength between RRP and OPC by using fine particles of RRP. Maintaini...
Advances in Animal and Veterinary Sciences, 2020
Cichorium intybus L. "Chicory" is an edible plant that belongs to the family Asteraceae, growing ... more Cichorium intybus L. "Chicory" is an edible plant that belongs to the family Asteraceae, growing in Europe, India, and Egypt. The plant contains several medicinally important compounds such as coumarins, flavonoids, and vitamins and used in traditional medicine as an antihepatotoxic, anti-inflammatory, liver tonic, cholagogue, diuretic and also is used as a tonic and anticancer agent (Liu et al., 2013;
Structures, 2020
A Considerable research work has investigated the behavior and strength of deep beams with transv... more A Considerable research work has investigated the behavior and strength of deep beams with transverse openings. However, the focus was mainly on deep beams with rectangular sections, while no experimental data are available on the behavior of flanged deep beams. As result, most design codes and guidelines neglect the effect of flange on the strength and stiffness of deep beams with openings. This study aims to enrich the literature by reporting the experimental data of sixteen deep beams: twelve with flanged section (with or without opening) and four reference beams with rectangular section. The shear span to depth ratio (a/d) was 1.10. The openings in the beams' web had a constant depth (120 mm) and varied lengths (120 mm, 240 mm, and 360 mm). The effect of flange on the strength, stiffness, and deformation capacity of the tested beams was assessed. The results were analyzed in terms of cracking pattern, mode of failure, load-deflection behavior, deformations distribution, and strains in reinforcement. Prediction of the experimentally obtained behavior using finite element model was introduced. Assessment of ultimate strengths based on the available design equations and analytical models was also discussed. The test results clearly showed that the flange resulted in a significant gain in the strength and stiffness that cannot be ignored in the design. The FEA was shown to provide a reasonably accurate estimation of the experimental behavior for the tested beams. With the assumptions made herein, the modified compression field theory (MCFT) prediction was the closest to the experimental results.
2016 28th International Conference on Microelectronics (ICM), 2016
This paper presents a system level design for a proposed Hall sensor chip fabricated in 0.35 μm C... more This paper presents a system level design for a proposed Hall sensor chip fabricated in 0.35 μm CMOS used in power meters. Based on theoretical analysis on key circuits and system of Hall sensor, important system parameters have been selected. In order to verify the design, a system model based on SIMULINK is built and a comparison between the simulated and the measured results of a prototype Hall sensor is presented for verification.
2016 Fourth International Japan-Egypt Conference on Electronics, Communications and Computers (JEC-ECC), 2016
This paper introduces a sensing and stimulation system to transfer the electromyogram (EMG) signa... more This paper introduces a sensing and stimulation system to transfer the electromyogram (EMG) signal from one limb to another, aiming to enable self-electro-physical therapy. The presented technique depends on sensing EMG signal from one limb muscle and, simultaneously, stimulating the corresponding muscle in the other limb by this signal. The technique has been implemented on a standalone cheap microcontroller. The sensing and stimulating circuits have been implemented using off-shelf components. The delivery of the stimulating signal has been done noninvasively through surface electrodes.
Optoelectronic Circuits in Nanometer CMOS Technology, 2016
Optoelectronic Circuits in Nanometer CMOS Technology, 2016
Springer Series in Advanced Microelectronics, 2016
This study was to investigate the influence of pre-sowing treatment of Anethum graveolens L. seed... more This study was to investigate the influence of pre-sowing treatment of Anethum graveolens L. seeds, consisted in irradiation with gamma radiation (0, 2, 4, 8, 16, 32 and 64 k-rd doses) with or without zinc (150 ppm), on the oil content and oil composition of plants during vegetative, flowering and fruiting stages. Spraying dill plants with zinc increased the oil content. Generally increasing gamma rays doses increased essential oil. However interaction treatment between zinc and gamma radiation at 8 k-rad dose recorded the highest values of essential oil in vegetative and fruiting stages, while interaction between zinc and gamma radiation at 2 k-rad dose recorded the highest essential oil in flowering stage. The major compounds were found to be Į-phellandrene, limonene, β-phellandrene and p-cymene in the vegetative stage, p-cymene, carvone, dillether and dillapiole in the flowering stage, whereas, carvone, dillapiole and limonene in the fruiting stage.
2015 IEEE International Symposium on Circuits and Systems (ISCAS), 2015
A high-resolution time-to-digital converter (TDC) using switched-ring oscillator (SRO) is present... more A high-resolution time-to-digital converter (TDC) using switched-ring oscillator (SRO) is presented. The proposed TDC relies on oversampling and second-order noise-shaping to achieve the targeted resolution without the need for calibration. The theory as well as the comparison with existing techniques are presented in this paper. In addition, the circuit implementation using 130 nm CMOS process is demonstrated. The proposed TDC operates over a wide range of input carrier frequencies (0.6-750 MHz) and sampling rates (50-750 MS/s). Simulation results show that, at 500 MS/s and 80 MHz carrier frequency, integrated noise (effective TDC resolution) of 157 fs, 271 fs, and 375 fs are achieved with integrated bandwidths of 1 MHz, 5 MHz and 10 MHz, respectively. The proposed TDC consumes 1.7 mW from 1.2 V supply.
2015 32nd National Radio Science Conference (NRSC), 2015
Through this paper we aim to measure a distance using an optical signal. The distance measurement... more Through this paper we aim to measure a distance using an optical signal. The distance measurement is based on the time of the flight (TOF) method via correlation technique. A method of stretching the time scale is used to decrease the operating frequency. A proof of concept using Matlab results in a distance resolution less than 17mm. The algorithm is implemented on a standalone cheap digital signal controller and the measured results show high accuracy comparable to the simulated one. The optical transmitters and optical receivers are implemented using off shelf components.
Springer Series in Optical Sciences, 2012
Optical absorption in a semiconductor material is the key-effect to convert optical power into an... more Optical absorption in a semiconductor material is the key-effect to convert optical power into an electrical current. This conversion is done by an integrated photodiode in the integrated optical receivers introduced in this book. Discrete photodiodes can be connected to transimpedance amplifier ICs in multi-chip packages by wire bonding or in hybrid integrated circuits. The advantage of discrete solution is that the performance for each device can be optimized separately by using special photodiode and IC technologies. The drawback is high costs due to a complex production and assembly process. Other disadvantages of using discrete photodiodes are potential noise sources and bandwidth reduction due to bonding pads and package pins.
2014 31st National Radio Science Conference (NRSC), 2014
ABSTRACT An optical receiver with an integrated equalizer fabricated in 0.6μm BiCMOS technology i... more ABSTRACT An optical receiver with an integrated equalizer fabricated in 0.6μm BiCMOS technology is presented. The integrated equalizer compensates the bandwidth limitation of the Resonant Cavity Light Emitting Diode (RC-LED), large-area integrated photodiode and Plastic Optical Fibre (POF) link. Free of error transmission (BER=10-9) at data rate of 1Gbit/s is achieved for 50m POF length.
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Papers by Mohamed A Ibrahim