ahmed soliman
El Azher University, Fucalty of Scince, Graduate Student
- Zoos and Aquariums, Fisheries and aquaculture economics, Fish Genetics, Marine Biology and Fisheries, Ecotoxicology, Nanoecotoxicology, and 119 moreFisheries, Nanotechnology, Environmental Sustainability, Biotechnology, Nanobiotechnology, Bionanotechnology, Aquatic Nanotoxicology, Nanoscience, Aquatic Toxicology, Nanotoxicology, Toxicity of various silver nanoparticles compared to silver ions in Daphnia magna, Brine shrimp, Live Food, Larviculture, Fish Nutrition, Molecular Genetics, Genetics, Fisheries Management, Environmental Biotechnology, Sociology of Fisheries and Aquaculture, Fisheries Economics, Scientific innovation on Fisheries and Marine Science, Fisheries Research, Genetic enginnering, gene transfer, Immunology, Molecular Biology, Bioinformatics, Genetic Engineering, Marine and Fisheries Policy, Ecosystem-Based Fisheries Management, Climate Impacts to Fisheries, Traditional Ecological Knowledge, Ecosystem Modelling, Illegal, Unreported and Unregulated (IUU) Fishing, Traditional Fisheries, Marine Aquaculture, Aquaculture, Plant Biology, Phytochemistry, Photosynthesis, Marine BioTechnology, Marine Resources, Marine Biology, Plant Ecology, Plant biotechnology, Industrial Biotechnology, Plant Physiology (Biology), Plant Science, Phycology, Algae, Hydrogen, Algal Biofuels, MARINE POLLUTION, Polyamines, Biodegradable polymer composites, Kappaphycus Alvarezii, Cytotoxicity, Polymer Chemistry, Seaweeds, Natural product research, Bioindicators, Tropical Medicine, Pharmacology, Marine Ecology, Toxicology, Plant Ecophysiology, Algae Biotechnology, Medicinal Plants, Aquaculture Economics and Management, Microalgae, Seaweed disease, Pigments (Chemistry), Applied Phycology, Astrobiology, Seaweed, Red Algae, Botany, Physiology, Natural Products Chemistry, Phytochemical Screening of Medicinal Plants, Polysaccharides, Phytotherapy, Medicinal plants and natural products, Marine Science, Bioeconomics, Natural Resource and Environmental Economics, Red algal defense mechanisms, Natural Products, New Drug Discovery, Natural Products and drug discovery, Bioactive Compounds and Phytochemicals in Foos, Conservation Science, Iberian Prehistory (Archaeology), Endangered Species, Conservation Biology, Biodiversity, Ecology, Science Communication, Environmental Education, Human-wildlife conflicts, Wildlife Conservation, Iberian Studies, Archaeology of the Iberian Peninsula, Bushmeat Hunting, Geography, Environmental History, Transnational and World History, Animal Ethics, Environmental Ethics, Human-Animal Relations, Feminist Philosophy, Dolphins in captivity, Animal Cognition, Conceptual Metaphor, Whales, Ethics, Dolphins, Feminist Epistemology, and Human-Animal Studiesedit
ABSTRACT This paper presents a Field Programmable Gate Array (FPGA) implementation for video compression using a Block Truncation Coding (BTC) image compression technique. The implementation exploits the inherent parallelism of the BTC... more
ABSTRACT This paper presents a Field Programmable Gate Array (FPGA) implementation for video compression using a Block Truncation Coding (BTC) image compression technique. The implementation exploits the inherent parallelism of the BTC algorithm to provide efficient algorithm-to-architecture mapping. The Xilinx VirtexE BTC implementation has shown to provide 20.5 × 106 of pixels per second, which is about 3000 times faster than an Intel Pentium III 550 MHz processor.
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This paper explores the possibility of enhancing the performance of genetic algorithms (GA) in automating the design of combinational circuits by multi-objective optimization using problem specific genetic operators. The objective is to... more
This paper explores the possibility of enhancing the performance of genetic algorithms (GA) in automating the design of combinational circuits by multi-objective optimization using problem specific genetic operators. The objective is to design digital circuits with 100% functionality and minimum number of logic gates. Experiments are carried out to assess the performance of the proposed algorithm against a conventional genetic
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... Akmal A. Younis, Ahmed T. Soliman, Mansur R. Kabuka, and Nigel M. John Department ofElectrical and Computer Engineering, University ofMiami, Miami, FL, USA ayounisgmiami.edu, a.solimangumiami.edu, m.kabukagmiami.edu,... more
... Akmal A. Younis, Ahmed T. Soliman, Mansur R. Kabuka, and Nigel M. John Department ofElectrical and Computer Engineering, University ofMiami, Miami, FL, USA ayounisgmiami.edu, a.solimangumiami.edu, m.kabukagmiami.edu, nigel.johngmiami.edu Abstract ...
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As the construction industry adapts to increasingly more stringent environmental and economic regulations, the efficient usage of materials and energy becomes evermore essential. Partially replacing cement with relatively inert filler... more
As the construction industry adapts to increasingly more stringent environmental and economic regulations, the efficient usage of materials and energy becomes evermore essential. Partially replacing cement with relatively inert filler materials such as limestone powder had been used in Europe for several decades. More recently, ASTM allowed incorporating up to 5% limestone in ordinary portland cements, and higher rates are being considered. However, only a few studies have been carried out on ultra fine limestone and its potential as a cement hydration accelerating agent. In this study, the effect of using nano-limestone on the early-age properties of concrete was investigated. The potential of using nano-limestone as a hydration accelerator was evaluated compared to commercial chloride and non-chloride based accelerating admixtures. The results demonstrate that nano-limestone has a very effective cement hydration acceleration action, combined with a general improvement in concrete ...
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Ultra high-performance concrete (UHPC) represents a leap development in concrete technology. Its high strength and enhanced durability make it the ultimate building material for the construction, strengthening and rehabilitation of... more
Ultra high-performance concrete (UHPC) represents a leap development in concrete technology. Its high strength and enhanced durability make it the ultimate building material for the construction, strengthening and rehabilitation of bridges and other transportation infrastructure. However, UHPC is affected by high autogenous shrinkage due to its low water-to-binder ratio (w/b). Moreover, exposure to drying conditions during early-age is of particular concern in repairing, overlaying bridge slabs, and other application where the exposed surface area per unit volume of material is relatively high. To understand the mechanisms that govern UHPC shrinkage, it is necessary to understand the real effects that exist in elements cast in-situ and cured at ambient temperature (i.e. without heat curing). This should motivate taking the UHPC technology from the laboratory to field construction. Therefore, the relationship between drying and autogenous shrinkage under variable temperature and ambi...
Zusammenfassung Koralleriffartige Plaquebildungen im Bereich der supra- und juxtarenalen Aorta sind seltene und in der Literatur nur als Einzelfälle beschriebene arteriosklerotische Wandveränderungen, welche vorwiegend Frauen, meist... more
Zusammenfassung Koralleriffartige Plaquebildungen im Bereich der supra- und juxtarenalen Aorta sind seltene und in der Literatur nur als Einzelfälle beschriebene arteriosklerotische Wandveränderungen, welche vorwiegend Frauen, meist zwischen 40 und 60 Jahren, betreffen. Symptomatisch werden die Patienten mit arterieller Hypertonie, Niereninsuffizienz, Angina abdominalis und/oder Claudicatio intermittens, welche durch die Progression der lumeneinengenden Korallenriffsklerose, insbesondere auch der Viszeral- und Nierenarterienabgänge, zu erklären sind.
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Concrete shrinkage cracking is a common problem in all types of concrete structures, especially at environments where the cracks are prevalent and the repercussions are most severe. Shrinkage reducing admixture (SRA) has been used to... more
Concrete shrinkage cracking is a common problem in all types of concrete structures, especially at environments where the cracks are prevalent and the repercussions are most severe. Shrinkage reducing admixture (SRA) has been used to improve concrete performance in terms of lower risk of cracking related to shrinkage. Substantial results are available in the literature to illustrate SRA influence on concrete shrinkage. However, SRA cannot definitively and safely avoid the risk of cracking caused in real concrete structures under the practical field conditions. In this study, the early-age shrinkage behaviour of Ultra-High Performance Concrete (UHPC) incorporating SRA is investigated under simulated field conditions. The simulated field conditions included drying/wetting cycles and submerged conditions, and were compared to sealed and drying conditions under constant temperature and relative humidity. The results show the substantial influence of environmental conditions on the shrin...
... E-mail: rania_fahmed@yahoo.com Ahmed M. Soliman ... 41, pp.918-921, Dec. 1994. [3] HO Elwan and AM Soliman," CMOS differential current conveyors and applications for analog VLSI," Analog Integrated Circuits and Signal... more
... E-mail: rania_fahmed@yahoo.com Ahmed M. Soliman ... 41, pp.918-921, Dec. 1994. [3] HO Elwan and AM Soliman," CMOS differential current conveyors and applications for analog VLSI," Analog Integrated Circuits and Signal Processing, vol. 11, pp. 35-45, 1996. ...
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ABSTRACT A novel reconfigurable independent multiband CPW fed printed inverted F-antenna is presented in this paper for USB and wireless communication applications. The proposed antenna consists of four arms CPW fed IFAs loaded with four... more
ABSTRACT A novel reconfigurable independent multiband CPW fed printed inverted F-antenna is presented in this paper for USB and wireless communication applications. The proposed antenna consists of four arms CPW fed IFAs loaded with four capacitive plates for size reduction. To avoid frequency steering problem, four varactor diodes are added. Varactor diodes with variable capacitors are added on each printed-IFA arms to electrically and independently tune the operating resonant frequencies over a wide frequency range. The size of the USB antenna is 16 × 20 mm2 which makes it easy to be integrated into USB package. Depending on the voltage applied to the vractor diode, the resonant frequencies could be operated at 1.3 GHz, 1.6 GHz, 2.8 GHz and 4.9 GHz and could be tuned over frequency range 11.5%, 12.5%, 25% and 28.5%, respectively from its resonant frequency. i.e., it covers several communication standards. The radiation patterns are provided. Very good agreements are achieved between measurements and EM simulations with the theoretical predictions.
In this study, the effect of incorporating wollastonite micro-fibers on the early-age properties of ultra-high performance concrete (UHPC) was investigated. Three series of specimens containing different sizes of wollastonite micro-fibers... more
In this study, the effect of incorporating wollastonite micro-fibers on the early-age properties of ultra-high performance concrete (UHPC) was investigated. Three series of specimens containing different sizes of wollastonite micro-fibers were tested. Wollastonite micro-fibers were added at 0, 4, 8 and 12% as a volume replacement for cement. Results show that the early-age properties of UHPC mixtures incorporating wollastonite micro-fibers are highly affected by the micro-fibers content and aspect ratio. Moreover, mixtures incorporating a high level of wollastonite micro-fibers exhibited comparable to or higher compressive strength than that of the reference mixture without micro-fibers. The addition of wollastonite micro-fibers reduced shrinkage strains and increased the crack resistance. It is shown that wollastonite micro-fiber can act as an internal restraint for shrinkage, reinforcing the microstructure at the micro-crack level and leading to enhanced engineering properties. In...
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Design and simulation of a digitally controlled CMOS fully differential current conveyor (DCFDCC) is presented. A novel current division network (CDN) is used to provide the digital control of the current gain between terminals X and Z of... more
Design and simulation of a digitally controlled CMOS fully differential current conveyor (DCFDCC) is presented. A novel current division network (CDN) is used to provide the digital control of the current gain between terminals X and Z of this DCFDCC. The proposed DCFDCC operates under low supply voltage of ±1.5 V. The realization of the DCFDCC using the new CDN
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These days, concrete plays an important role in the development of safe and economical construction projects. The high demand for concrete results in a high cement consumption, which has serious environmental impacts due to energy... more
These days, concrete plays an important role in the development of safe and economical construction projects. The high demand for concrete results in a high cement consumption, which has serious environmental impacts due to energy consumption and CO 2 emissions associated with cement production. Therefore, finding material that can replace cement while maintaining the same high performance becomes a must. Currently, micro-limestone exhibited a world-wide acceptance as a partial replacement of cement. In this study, the potential of using different dosages and sizes of micro-limestone and its effect on the development of concrete properties was investigated. Primary results showed no detrimental effects with the incorporation of limestone. Increasing the size of limestone did not accelerate the hydration process, indicating that this fine material contributes mainly as filler. In addition, an optimum dosage of limestone was found, which produced the greatest strength improvement, and...
Two novel active RC oscillator circuits suitable for integration are given. The active building block used is the current conveyor. Both networks have the advantage of using earthed capacitors. One circuit is of a second order and uses... more
Two novel active RC oscillator circuits suitable for integration are given. The active building block used is the current conveyor. Both networks have the advantage of using earthed capacitors. One circuit is of a second order and uses two opposite polarity current conveyors and the other is a third-order oscillator with the advantage of using only one current conveyor.
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This study proposes the concept of self-accelerated concrete through using partially-hydrated cementitious materials (premade or taken from returned/unused concrete). The effect of adding partially-hydrated cementitious materials (PHCMs)... more
This study proposes the concept of self-accelerated concrete through using partially-hydrated cementitious materials (premade or taken from returned/unused concrete). The effect of adding partially-hydrated cementitious materials (PHCMs) on the setting and hardening process of concrete cured at various temperatures was investigated. The PHCMs were added at rates of 25, 33 and 50% of the overall batch weight. Similar mixtures incorporating chloride and non-chloride based accelerating admixtures were also tested for comparison. The results indicate that the added PHCMs alert the hydration kinetics and act as a setting and hardening accelerator. Mixtures incorporating PHCMS showed comparable to and/or higher early-age compressive strength than that of both the control and mixtures incorporating commercial accelerating admixtures. Therefore, using PHCMs pave the way for self-accelerated concrete, without the need for accelerating admixtures, providing a safe and cost effective method fo...
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ABSTRACT The mechanical properties of two-stage concrete (TSC) made with various grout mixtures and incorporating single, binary, and ternary binders were investigated in the present study. Different supplementary cementitious materials,... more
ABSTRACT The mechanical properties of two-stage concrete (TSC) made with various grout mixtures and incorporating single, binary, and ternary binders were investigated in the present study. Different supplementary cementitious materials, including class F fly ash, silica fume and metakaolin were added as partial replacement for ordinary Portland cement. Mechanical properties of TSC including compressive and tensile strength and modulus of elasticity at 7, 28, and 56 days were evaluated. Results show that the binder composition has a great influence on the fresh and hardened properties of the grout used in TSC and consequently on TSC’s mechanical properties. Moreover, empirical relationships between the properties of the grout and those of the corresponding TSC were proposed, offering a potential tool for estimating TSC properties based on primary grout properties.
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In this paper, an ultra-low-voltage charge pump is presented. Two techniques are used to reduce required number of stages and improve power efficiency, namely clock boosting and Vt cancellation. Clock boosting is employed to increase the... more
In this paper, an ultra-low-voltage charge pump is presented. Two techniques are used to reduce required number of stages and improve power efficiency, namely clock boosting and Vt cancellation. Clock boosting is employed to increase the output voltage per stage resulting in lower number of stages, and hence smaller output resistance. Vt cancellation is achieved by using an auxiliary circuit that enables the charge pump to operate at input voltages as low as 300mV. Compared to conventional charge pump techniques, the proposed technique is shown to offer higher power efficiency and voltage gain. The charge pump is designed using TSMC 0.25 µm CMOS technology.
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The objective of this paper is to develop a methodology to construct and compute in a Bayesian setting, point and interval predictions based on general progressive Type-II censored data from Weibull model. Prediction bounds for the future... more
The objective of this paper is to develop a methodology to construct and compute in a Bayesian setting, point and interval predictions based on general progressive Type-II censored data from Weibull model. Prediction bounds for the future observations (2-sample prediction) based on this type of censored will be derived. Bayesian predictions are obtained based on a continuous–discrete joint prior for the unknown two parameters. We have examined point predictions under symmetric and asymmetric loss functions. As application, the total duration time in a life test and the failure time of a k-out-of-m system may be predicted. An illustrative example consisting of various types of real data from an accelerated test on insulating fluid reported by Nelson (1982) [17] is presented. Finally, some numerical results using simulation study concerning different sample sizes, and different progressive censoring schemes were reported. A study of 10000 randomly generated future samples from the sam...
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ABSTRACT Durability of concrete exposed to sulfates has primarily been studied on specimens fully-submerged in sulfate solutions. However, field experience shows that concrete exposed to sulfates can suffer from surface scaling above... more
ABSTRACT Durability of concrete exposed to sulfates has primarily been studied on specimens fully-submerged in sulfate solutions. However, field experience shows that concrete exposed to sulfates can suffer from surface scaling above ground level due to physical attack. This damage has often been ignored and even confused with chemical sulfate attack. In this study, concrete partially-immersed in sulfate solutions and exposed to cyclic temperature and relative humidity was explored. Results show that concrete can experience dual sulfate attack. The lower immersed portion can suffer from chemical sulfate attack, while the upper portion can be vulnerable to physical attack. Lowering the water-to-binder ratio and moist-curing reduced surface scaling above the solution level, since the volume of pores was decreased. Although partial replacement of cement with pozzolans also decreased the pore volume, surface scaling increased due to increased proportion of small diameter pores and associated growth of capillary suction and surface area for evaporation.
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ABSTRACT Simple multiband/wideband planar inverted-F antenna (PIFA) over artificial ground plane for wireless communication applications is proposed in this paper. The multiband/wideband and size reduction characteristics are created by... more
ABSTRACT Simple multiband/wideband planar inverted-F antenna (PIFA) over artificial ground plane for wireless communication applications is proposed in this paper. The multiband/wideband and size reduction characteristics are created by means of combining co-planar wave guide feeding technique based PIFA over a common electromagnetic band-gap (EBG) ground plane. The proposed antenna is designed to cover a narrow band at 1.3 GHz and a wideband from 2.8 GHz to 6.5 GHz with 27% size reduction for the fundamental resonant frequency of the CPW fed PIFA compared to the original size. The EBG structure that is used is a uniplanar EBG. The EBG introduces inductive and capacitive loading under the CPW fed transmission line to improve the antenna performance. A prototype antenna has been fabricated and tested.
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ABSTRACT Concrete exposed to sulfates in hot and arid regions can severely suffer from salt weathering. The resulting damage is typically localized at the above ground portion of concrete members. This process highly depends on the pore... more
ABSTRACT Concrete exposed to sulfates in hot and arid regions can severely suffer from salt weathering. The resulting damage is typically localized at the above ground portion of concrete members. This process highly depends on the pore structure of the concrete surface through which salty water rises by capillary action. When water evaporates, salt crystals grow in the concrete surface pores leading to concrete damage. Thus, protecting the concrete surface can potentially enhance its durability to salt weathering. However, the vast variety of surface treatment compounds available makes the selection of an adequate material challenging. This is particularly true for concrete exposed to physical sulfate attack due to the lack of pertinent data in the open literature. Therefore, this study focuses primarily on assessing the effectiveness of different commercially available surface treatment materials in mitigating physical sulfate attack on concrete.
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ABSTRACT Precast concrete shear walls are used to resist lateral loads in low- to medium-rise buildings. This paper introduces an innovated joining technique for these precast walls that will reduce the possibility of concrete damage and... more
ABSTRACT Precast concrete shear walls are used to resist lateral loads in low- to medium-rise buildings. This paper introduces an innovated joining technique for these precast walls that will reduce the possibility of concrete damage and capital loss during earthquake events. The proposed technique consists of precast panels joined together and to the base using threaded steel anchor bolts, which in turn makes the construction process easier and faster. An experimental programme is conducted to validate this system and characterise its behaviour under lateral loads. Four reduced-scale wall specimens are tested under monotonic in-plane horizontal load. The lateral strength, ductility and possible modes of failure are used to evaluate the connection performance. The joined precast shear wall exhibits a high non-linear deformation without any signs of panel damage, which can be attributed to the gap opening and steel yielding at the connection plane. This indicates that the steel anchor bolts at the connection can be designed to act as structural ductile fuses.
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ABSTRACT Ultra-high performance concrete (UHPC) is a new generation of steel fiber-reinforced concrete with superior mechanical and durability properties. However, limited data is available on the influence of the steel fiber length and... more
ABSTRACT Ultra-high performance concrete (UHPC) is a new generation of steel fiber-reinforced concrete with superior mechanical and durability properties. However, limited data is available on the influence of the steel fiber length and dosage on UHPC mechanical and durability performance. Therefore, in this study, a number of UHPC mixtures with varying steel fiber lengths (8 mm (0.31 in), 12 mm (0.47 in) and 16 mm (0.62 in)) and dosages (1%, 3% and 6%) by mixture volume were tested. Mechanical properties of UHPC including compressive, splitting tensile and flexural strengths were assessed. Moreover, its resistance to chloride ions penetration and mechanical degradation under various chloride exposures (i.e. 3.5% and 10%) were evaluated. Results showed an increase in mechanical properties as the fiber dosage increased. UHPC mixtures incorporating short steel fibers exhibited enhanced flexural properties compared to that of mixtures with similar volume of longer steel fibers. At higher fiber dosage, UHPC mixtures exhibited relatively improved durability. Moreover, no degradation in UHPC mechanical properties was observed after exposure to various chloride ions solutions.