Some recent advances in hierarchical modeling strategies are reviewed with special emphasis on applications to multilayered composite panels. Discussion focuses on the key elements of hierarchical ...adaptive modeling, multimodel predictor-corrector modeling procedures, potential for solving large complex problems and the needed development to realize this potential. Numerical studies are presented for free vibrations of thermally-stressed multilayered composite panels and structural sandwiches with composite face sheets, demonstrating the effectiveness of the multimodel predictor-corrector modeling approaches.
New Wide Band Low Power CMOS Current Conveyors Hassanein, Wessam S.; Awad, Inas A.; Soliman, Ahmed M.
Analog integrated circuits and signal processing,
07/2004, Volume:
40, Issue:
1
Journal Article
Peer reviewed
New Class-A second-generation CMOS current conveyor (CCII) suitable for high frequency applications is proposed. It provides low input impedance and accurate voltage and current tracking. Targeting ...low power dissipation, the Class-AB version of the proposed Class-A architecture is introduced as well. Simulation results are included.
: Functions attributed to phospholipase (PL) D include the regulation of intracellular trafficking of Golgi‐derived vesicles and secretion of granules from mast cells. We have reported that ...activation of PLD and secretion in a rat mast cell (RBL‐2H3) line is substantially enhanced by cholera toxin, a known activator of protein kinase (PK) A. Here we review the evidence that (1) the synergistic interactions of cholera toxin and other pharmacological agents on mast cell secretion are attributable to the synergistic activation of PLD via PKA, CaM kinase II, and PKC and (2) both PLD1 and PLD2 participate in this process. For example, treatment with cholera toxin, thapsigargin, and phorbol 12‐myristate 13‐acetate (which activate PKA, CaM kinase II, and PKC, respectively) exhibit synergy in the stimulation of both PLD and secretion. These kinases and PLD are likely confined to membrane components, as similar synergistic interactions could be demonstrated in permeabilized cells. The regulation of PLD and secretion by these kinases is also apparent from studies of inhibitors of PKA and other kinases. Also, by overexpression of either PLD1 or PLD2 it is apparent that both isoforms respond to the same stimuli as endogenous PLD, although PLD1 is largely associated with secretory granules and PLD2 with plasma membrane. The studies reveal interesting differences in the regulation of the translocation of granules (regulated by PKA) and the fusion of these granules with the plasma membrane (regulated by Ca2+ and PKC). The pathological/physiological implications of the regulation of PLD by PKA require further evaluation in other cell systems.
Massive machine-type communications (mMTC) is a major use case in the fifth generation (5G) wireless networks. mMTC aims at supporting a large number of Internet of Things (IoT) connections within a ...coverage area. The current random access procedure in the Long Term Evolution (LTE) networks may not be able to handle a large number of simultaneous connection requests due to the limited number of random access preambles. Hence, it is essential to modify the random access procedure to support mMTC. In this paper, we propose a new preamble sequence design in which two Zadoff-Chu preamble sequences are aggregated together. This design enables us to have a larger set of random access preambles consisting of all combinations of pairing two Zadoff-Chu preamble sequences. Moreover, we consider a subset of all combinations that satisfy a certain maximum peak-to-average-power-ratio (PAPR) threshold criterion to reduce the energy consumption of the IoT devices. The proposed design requires only minor changes in the conventional transmitter and receiver design for generating and decoding the aggregated preamble sequences, respectively. Results show that the proposed design reduces the probability of preamble collision to less than 10 -4 , which is lower than LTE. Furthermore, it outperforms other collision avoidance techniques such as access class barring (ACB) in terms of a lower average total service time. The modified receiver detects the aggregated preambles successfully and avoids detecting false preambles. Both the probabilities of misdetection and false alarm are less than 10 -3 when the signal-to-noise ratio (SNR) is larger than -7 dB.
The global energy demand is projected to rise by almost 28% by 2040 compared to current levels. Biomass is a promising energy source for producing either solid or liquid fuels. Biofuels are ...alternatives to fossil fuels to reduce anthropogenic greenhouse gas emissions. Nonetheless, policy decisions for biofuels should be based on evidence that biofuels are produced in a sustainable manner. To this end, life cycle assessment (LCA) provides information on environmental impacts associated with biofuel production chains. Here, we review advances in biomass conversion to biofuels and their environmental impact by life cycle assessment. Processes are gasification, combustion, pyrolysis, enzymatic hydrolysis routes and fermentation. Thermochemical processes are classified into low temperature, below 300 °C, and high temperature, higher than 300 °C, i.e. gasification, combustion and pyrolysis. Pyrolysis is promising because it operates at a relatively lower temperature of up to 500 °C, compared to gasification, which operates at 800–1300 °C. We focus on 1) the drawbacks and advantages of the thermochemical and biochemical conversion routes of biomass into various fuels and the possibility of integrating these routes for better process efficiency; 2) methodological approaches and key findings from 40 LCA studies on biomass to biofuel conversion pathways published from 2019 to 2021; and 3) bibliometric trends and knowledge gaps in biomass conversion into biofuels using thermochemical and biochemical routes. The integration of hydrothermal and biochemical routes is promising for the circular economy.
The role of phospholipase (PL) D in secretion was examined in RBL-2H3 mast cells which contain both PLD1 and 2. The effects of pharmacologic stimulants and inhibitors of Ca
2+/calmodulin-dependent ...kinase II, protein kinase C, and protein kinase A suggested that all three kinases synergistically stimulate PLD and, when associated with a calcium signal, secretion as well to indicate a possible linkage between these two events. Overexpression of either PLD1 or 2 markedly enhanced the activation of PLD by pharmacologic stimulants as well as antigen and both isoforms thus appear co-ordinately regulated. As the expressed PLD1 was associated with secretory granules and PLD2 with the plasma membrane, the two isoforms may serve distinct but complementary functions in secretion.
Increasing emissions of carbon dioxide (CO2) into the atmosphere is a global issue that needs to critically resolve in order to slow down the worsening threat of climate change. Significant studies ...over the past few decades has been subjected to solve that problem. In the present study, aqueous carbonate solution activated by alkanolamine was used for capturing CO 2 from flue gas in a packed absorber column. The absorption experiments were performed at operating temperature of 298 K and atmospheric pressure using 15 % v/v CO2. Whereas, desorption experiments were conducted at temperature of 363 K. The absorption performance of 30 wt% (1M) potassium carbonate (K2CO3) solution when adding 5% of monoethanolamine (MEA), ethanolamine (DEA) and triethanolamine (TEA) was evaluated. It was found that the addition of promoter increase the absorption rate of potassium carbonate solution and enhance all other solvent characteristics.
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