scholarly journals Complex model description and main capacitor sizing for the cross-coupled charge pump synthesis process

2018 ◽  
Vol 69 (5) ◽  
pp. 337-344
Author(s):  
Jan Marek ◽  
Jiri Hospodka ◽  
Ondrej Subrt

Abstract This paper presents a dynamic part of the pump stage model of the cross-coupled charge pump. The complex model has been used for both the estimation of the N-stage pump properties in a wide range of the input parameters and derivation of equations for synthesis process, as the main capacitor sizing, which is also mentioned in the article. Dynamic part of the model (pump stage capacitances) is determined from Ward’s capacitance piece-wise model through the BSIM MOSFET model equations. Main capacitor and load capacitor sizing are based on the time response characteristics fulfilling the system behavior in time. Guideline on the MOS transistor sizing as the nonlinear main pump capacitor and specification of the diode transistor for the design process are also clarified. The characteristics of the proposed circuit have been verified in the professional design environment Mentor graphics and analysis algorithm based on the state-space description of the inner complex model was programmed in Maple SW. The main benefit is to offer the alternative way of the charge pump synthesis by using the complex model and symbolic description of all formulae to find the required pump parameters without long-time simulation process.

2002 ◽  
Vol 716 ◽  
Author(s):  
Nihar R. Mohapatra ◽  
Madhav P. Desai ◽  
Siva G. Narendra ◽  
V. Ramgopal Rao

AbstractThe impact of technology scaling on the MOS transistor performance is studied over a wide range of dielectric permittivities using two-dimensional (2-D) device simulations. It is found that the device short channel performance is degraded with increase in the dielectric permittivity due to an increase in dielectric physical thickness to channel length ratio. For Kgate greater than Ksi, we observe a substantial coupling between source and drain regions through the gate dielectric. We provide extensive 2-D device simulation results to prove this point. Since much of the coupling between source and drain occurs through the gate dielectric, it is observed that the overlap length is an important parameter for optimizing DC performance in the short channel MOS transistors. The effect of stacked gate dielectric and spacer dielectric on the MOS transistor performance is also studied to substantiate the above observations.


2018 ◽  
Vol 157 ◽  
pp. 02052 ◽  
Author(s):  
Krzysztof Talaśka ◽  
Dominik Wojtkowiak

Due to the wide range of application for belt conveyors, engineers look for many different combinations of mechanical properties of conveyor and transmission belts. It can be made by creating multilayer or fibre reinforced composite materials from base thermoplastic or thermosetting polymers. In order to gain high strength with proper elasticity and friction coefficient, the core of the composite conveyor belt is made of polyamide film core, which can be combined with various types of polymer fabrics, films or even rubbers. In this paper authors show the complex model of multilayer composite belt with the polyamide core, which can be used in simulation analyses. The following model was derived based on the experimental research, which consisted of tensile, compression and shearing tests. In order to achieve the most accurate model, proper simulations in ABAQUS were made and then the results were compared with empirical mechanical characteristics of a conveyor belt. The main goal of this research is to fully describe the perforation process of conveyor and transmission belts for vacuum belt conveyors. The following model will help to develop design briefs for machines used for mechanical perforation.


Cerâmica ◽  
2014 ◽  
Vol 60 (356) ◽  
pp. 465-470 ◽  
Author(s):  
D. P. C. Velazco ◽  
E. F. Sancet ◽  
F. Urbaneja ◽  
M. Piccico ◽  
M. F. Serra ◽  
...  

Computer assisted designing (CAD) is well known for several decades and employed for ceramic manufacturing almost since the beginning, but usually employed in the first part of the projectual ideation processes, neither in the prototyping nor in the manufacturing stages. The rapid prototyping machines, also known as 3D printers, have the capacity to produce in a few hours real pieces using plastic materials of high resistance, with great precision and similarity with respect to the original, based on unprecedented digital models produced by means of modeling with specific design software or from the digitalization of existing parts using the so-called 3D scanners. The main objective of the work is to develop the methodology used in the entire process of building a part in ceramics from the interrelationship between traditional techniques and new technologies for the manufacture of prototypes. And to take advantage of the benefits that allow us this new reproduction technology. The experience was based on the generation of a complex piece, in digital format, which served as the model. A regular 15 cm icosahedron presented features complex enough not to advise the production of the model by means of the traditional techniques of ceramics (manual or mechanical). From this digital model, a plaster mold was made in the traditional way in order to slip cast clay based slurries, freely dried in air and fired and glazed in the traditional way. This experience has shown the working hypothesis and opens up the possibility of new lines of work to academic and technological levels that will be explored in the near future. This technology provides a wide range of options to address the formal aspect of a part to be performed for the field of design, architecture, industrial design, the traditional pottery, ceramic art, etc., which allow you to amplify the formal possibilities, save time and therefore costs when drafting the necessary and appropriate matrixes to each requirement.


2020 ◽  
Vol 5 (2) ◽  
Author(s):  
Evangelia A Pavlatou

The transmission of a wide range of diseases, related to the infection by pathogenic microorganisms is a major public health problem that daily endangers the safety of human population. Silver has been thoroughly studied and used against bacteria due to its antimicrobial properties. Nanostructured silver gathers all the advantages of the silver itself, as well as the advanced performance of the nanomaterials. Thus, currently, silver nanoparticles constitute the most widely used kind of nanoparticles in biomedicine, due to their attractive antimicrobial properties. A variety of physical and chemical methods are employed for the AgNPs synthesis. However, many of them include the use of toxic reagents or require large amounts of energy, during the synthesis process. For this reason, many eco-friendly methods are proposed in order to synthesize AgNPs. Hence, biogenic synthesis of AgNPs, utilizing biological resources opens a novel route for the development of alternative production processes.These methods seem to have significant advantages, as the extracts contribute positively to the formation and enhancement of the antimicrobial activity of AgNPs, also acting as protective agents of the produced particles. In this review an integrated approach of AgNPs bio-synthetic methods using microorganisms, such as bacteria and fungi, plants and plant extracts, as well as several templates, like DNA and viruses is discussed, shedding light on the comparative advantages of them.


2020 ◽  
Vol 8 (6) ◽  
pp. 4973-4977

The building norms and standards of Uzbekistan on the reinforced concrete structures do not regulate the design of hollow-core slabs of formwork-free shaping, reinforced with prestressed wire reinforcement. The manufacturing technology of such slabs allows creating a wide range of products that increase the possibility of their use in various structural systems in residential, civil and industrial buildings, but in non-seismic areas only. The aim of this work is to develop a constructive solution for the cross section of a prestressed hollow-core floor slab of bench formwork-free shaping, reinforced with high-strength wire reinforcement, in order to create a wide range of products intended for construction in seismic areas. To achieve the goal, the problem of determining the optimal combination of height and configuration parameters of the cross section of such a slab is solved, meeting the normalized operational requirements and limitations of earthquake-resistant building standards. The main variable parameters are the height and the void degree of the section, characterized by the size and shape of voids. In calculating the cross-section of a hollow-core slab when substantiating the theoretical basis for the calculation, the cross section is reduced to the equivalent I-section. As a result of research, a constructive solution was developed for the slab cross section of the maximum parameter values (the span, operational load) set by the customer. The parameters of the slab cross-section are: the height 190 mm, the hollowness 38%, the height of the upper thickened flange (compared with the height of the lower flange) of the given section is 0.27h, the height of the lower flange is 0.17h, the reduced (total) thickness of all ribs “b” is 0.32 of the width of the upper flange. The voids in the section along the height of the slab are arranged asymmetrically. A patent for a utility model has been received for the proposed constructive solution of the slab cross section.


1969 ◽  
Vol 39 (11) ◽  
pp. 1023-1030 ◽  
Author(s):  
Edith Honold ◽  
Stanley P. Rowland ◽  
James N. Grant

Differences in the ability of formaldehyde-crosslinked cotton fibers to swell are demonstrated in terms of alkali centrifuge values (ACV), i.e., the sorption of caustic solution of mercerizing strength. The wide range in ACV (310–50) emphasizes the extremes in sorptivity that can be achieved by differences in formaldehyde content and in method of introducing the cross links. In general, the ACV decreases with increasing formaldehyde content. However, ACV higher than that of the noncross-linked control cotton are reached for those samples in which a low percentage of formaldehyde was introduced into water-swollen fibers. Various hypotheses, based on ACV and related data, are presented pertaining to the alterations in fiber structure during the cross-linking processes and during the alkali swelling centrifuge test


2021 ◽  
Author(s):  
Clare M. Williams ◽  
Sreeja Roy ◽  
Danielle Califano ◽  
Andrew N. J. McKenzie ◽  
Dennis W. Metzger ◽  
...  

Interleukin (IL)-33 is a multifunctional cytokine that mediates type 2 dominated immune responses. In contrast, the role of IL-33 during viral vaccination, which often aims to induce type 1 immunity, has not been fully investigated. Here we examined the effects of IL-33 on influenza vaccine responses. We found that intranasal co-administration of IL-33 with an inactivated influenza virus vaccine increases the vaccine efficacy against influenza infection, not only with the homologous strain, but also heterologous strains including the 2009 H1N1 influenza pandemic strain. The cross-protection was dependent on group 2 innate lymphoid cells (ILC2s), as the beneficial effect of IL-33 on vaccine efficacy was abrogated in ILC2-deficient C57BL/6 Il7r P Cre/+ P Rora P fl/fl P mice. Further, mechanistic studies revealed that IL-33 activated ILC2s potentiate vaccine efficacy by enhancing mucosal humoral immunity, particularly IgA responses, potentially via a Th2 cytokine dependent manner. Our results demonstrate that IL-33-mediated activation of ILC2s is a critical early event that is important for the induction of mucosal humoral immunity, which in turn is responsible for cross-strain protection against influenza. Thus, we reveal a previously unrecognized role for the IL-33/ILC2 axis in establishing broadly protective and long-lasting humoral mucosal immunity against influenza – knowledge that may help develop a universal influenza vaccine. Importance Current influenza vaccines, although capable of protecting against predicted viruses/strains included in the vaccine, are inept at providing cross-protection against emerging/novel strains. Thus, we are in critical need for a universal vaccine that can protect against a wide range of influenza viruses. Our novel findings show that a mucosal vaccination strategy involving the activation of lung ILC2s is highly effective in eliciting cross-protective humoral immunity in the lungs. This suggests that the biology of lung ILC2s can be exploited to increase the cross-reactivity of commercially available influenza subunit vaccines.


2021 ◽  
Author(s):  
Angelo Odetti ◽  
Federica Braga ◽  
Fabio Brunetti ◽  
Massimo Caccia ◽  
Simone Marini ◽  
...  

<p>The IT-HR InnovaMare project, led by the Croatian Chamber of Economy, puts together policy instruments and key players for development of innovative technologies for the sustainable development of the Adriatic Sea (https://www.italy-croatia.eu/web/innovamare). The project aims at enhancing the cross-border cooperation among research, public and private stakeholders through creation of a Digital Innovation Hub (DIH). The goal is to increase effectiveness of innovation in underwater robotics and sensors to achieve and maintain a healthy and productive Adriatic Sea, as one of the crucial and strategic societal challenges existing at the cross-border level. Within InnovaMare, CNR ISMAR and INM institutes and OGS, in cooperation with the University of Zagreb and other project partners, contribute to developing a solution to access and monitor extremely shallow water by means of portable, modular, reconfigurable and highly maneuverable robotic vehicles. The identified vehicle is SWAMP, an innovative highly modular catamaran ASV recently developed by CNR-INM. SWAMP is characterised by small size, low draft, new materials, azimuth propulsion system for shallow waters and modular WiFi-based hardware&software architecture. Two SWAMP vehicles will be enhanced with a series of kits, tools and sensors to perform a series of strategic actions in the environmental monitoring of the Venice Lagoon: <br>i) An air-cushion-system-kit will be designed and developed. The vehicle will become a side-wall air-cushion-vehicle with reduction of drag and increase in speed. This will also increase the payload with a reduction of draft. <br>ii) An intelligent winch kit with a communication cable for the management of underwater sensors and tools.<br>iii) A GPS-RTK kit for highly accurate positioning in the range of centimeters.<br>iv) An Autonomous programmable device for image acquisition and processing based on the Guard1 camera. This camera acquires images content and, by means of a supervised machine learning approach, recognises/classifies features such as fish, zooplankton, seabed, infrastructures. The system is conceived for autonomous monitoring activities extended in time in fixed or mobile platforms.<br>v) A Multibeam Echo-sounder (MBES) coupled with an IMU (for pitch-roll compensation). MBES data can be used, also coupled with Cameras Imagery, through image-detection techniques for reconstruction and comprehensive knowledge of underwater environment and infrastructures. Possible analyses in coastal areas are: seabed mapping also for cultural heritage, offshore structures and resources and monitoring of biodiversity, hydrocarbon, marine litter, pollution.<br>vi) An underwater Radiometer for multiple analysis: temporal dynamics of optical properties of water; temporal dynamics of water turbidity from water reflectance; submerged vegetation and water depth mapping in optically shallow water; produce reference data for validation of satellite data.<br>vii) Automatic Nutrient Analyzer for real-time nutrient monitoring. This sensor measures nitrate with high accuracy over a wide range of environmental conditions (including extremely turbid and high CDOM conditions), from blue-ocean nitraclines to storm runoff in rivers and streams. <br>The final result of this pilot action is the creation of an innovative prototype platform for sea environmental monitoring. This will be validated through the analysis of results and draw up of guidelines for the improvement of underwater conditions.</p>


2019 ◽  
Vol 28 (06) ◽  
pp. 1950038 ◽  
Author(s):  
Suprita Chakraborty ◽  
Avijit Mukherjee ◽  
Subinit Roy

The radiative capture reaction [Formula: see text] is analyzed using a hybrid model approach where the non-resonant component has been constructed employing the potential model with a folded M3Y potential. The one-level Breit–Wigner formula has been used to estimate the cross-sections of the resonant decays of dominant ([Formula: see text]) state of [Formula: see text]N at 8.06[Formula: see text]MeV. The contribution of the broad resonance at 8.77[Formula: see text]MeV ([Formula: see text]) has been dealt with differently. While Breit–Wigner formula has been used where the excitation function data exist, the [Formula: see text]-matrix prediction for the cross-section of decay to a bound state of [Formula: see text]N from the broad resonance has been used where excitation function data are not available. The single particle spectroscopic factors for ground and six excited states of [Formula: see text]N have been obtained from the fits. The resulting astrophysical [Formula: see text]-factor at zero relative energy is [Formula: see text][Formula: see text]keV b. The value is in good agreement with the previously reported [Formula: see text]-matrix result and also consistent within error bars with the published values.


Sensors ◽  
2020 ◽  
Vol 20 (16) ◽  
pp. 4523 ◽  
Author(s):  
Jian Du ◽  
Li Wang ◽  
Yanbin Shi ◽  
Feng Zhang ◽  
Shiheng Hu ◽  
...  

The CNT-PDMS composite has been widely adopted in flexible devices due to its high elasticity, piezoresistivity, and biocompatibility. In a wide range of applications, CNT-PDMS composite sensors were used for resistive strain measurement. Accordingly, the percolation threshold 2%~4% of the CNT weight ratio in the CNT-PDMS composite was commonly selected, which is expected to achieve the optimized piezoresistive sensitivity. However, the linear range around the percolation threshold weight ratio (2%~4%) limits its application in a stable output of large strain (>20%). Therefore, comprehensive understanding of the electromechanical, mechanical, and electrical properties for the CNT-PDMS composite with different CNT weight ratios was expected. In this paper, a systematic study was conducted on the piezoresistivity, Young’s modulus, conductivity, impedance, and the cross-section morphology of different CNT weight ratios (1 to 10 wt%) of the CNT-PDMS composite material. It was experimentally observed that the piezo-resistive sensitivity of CNT-PDMS negatively correlated with the increase in the CNT weight ratio. However, the electrical conductivity, Young’s modulus, tensile strength, and the linear range of piezoresistive response of the CNT-PDMS composite positively correlated with the increase in CNT weight ratio. Furthermore, the mechanism of these phenomena was analyzed through the cross-section morphology of the CNT-PDMS composite material by using SEM imaging. From this analysis, a guideline was proposed for large strain (40%) measurement applications (e.g., motion monitoring of the human body of the finger, arm, foot, etc.), the CNT weight ratio 8 wt% was suggested to achieve the best piezoresistive sensitivity in the linear range.


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