Sensitivity of Flexibility Monitoring of Offshore Jacket Platforms

1986 ◽  
Vol 108 (1) ◽  
pp. 72-76 ◽  
Author(s):  
S. Rubin ◽  
R. N. Coppolino

Flexibility monitoring is a vibration-based method for simplifying the detection of major underwater damage on offshore jacket platforms. Ambient vibrations are detected at each of the underwater framing levels relative to abovewater vibration in the fundamental sway and torsional modes. Derived are flexibility parameters which relate to the shear flexibilities of each framing bay and of the foundation. Great promise has been shown by laboratory and field testing. This paper presents a comprehensive sensitivity assessment for severance of diagonal members over a wide range of structural redundancy for generic platform configurations.

2002 ◽  
Vol 2 (5-6) ◽  
pp. 209-216
Author(s):  
R. Sublet ◽  
A. Boireau ◽  
V.X. Yang ◽  
M.-O. Simonnot ◽  
C. Autugelle

Two lead removal water filters were developed to lower lead levels in drinking water below 10 μg.L-1 in order to meet the new regulation given by the European Directive 98-83, applicable in December 2013. An appropriate adsorbent was selected through a stringent research program among a wide range of media, and is composed of a synthetic zeolite and an activated carbon. Two prototypes were developed: the first is a faucet-mounted filter which contains a fixed bed of the adsorbent and a hollow fiber bundle, while the second is an under-sink cartridge made of a porous extruded block of carbon and adsorbent. Both are able to treat at least 1,000 litres of any water containing on average 100 to 150 μg Pb.L-1, by lowering the lead concentration below 10 μg.L-1. Once their safety considerations were addressed by an independent laboratory according to the French Ministry of Health recommendations, 20 prototypes were installed at consumers' taps in northeastern France. Their performance in terms of lead removal, HPC control and bad taste and odor reduction was followed for 6 months. This field testing program resulted in the validation of both prototypes which meet the new French Ministry of Health recommendations and assures that the filtered water is fully ED 98-83 compliant. Their commercialization will be launched first in France in middle 2002.


2016 ◽  
Vol 5 (11) ◽  
pp. 5110
Author(s):  
Sartaj Ahmad Allayie ◽  
Mushtaq Ahmed Parray* ◽  
Bilal Ahmad Bhat ◽  
S. Hemalatha

The use of traditional medicines holds a great promise as an easily available source as effective medicinal agents to cure a wide range of ailments among the people particularly in tropical developing countries like India. The present study investigates the qualitative and quantitative analysis of the major bioactive constituents of N. crenulata leaf extracts. The extractive values of aqueous, acetone and chloroform extracts were found to be 11.34, 4.24 and 6.06 respectively. Qualitative phytochemical analysis of these three solvent extracts confirm the presence of Alkaloids, Saponins, Flavonoids and Phenolic compounds in all the three extracts; however, these phytochemicals were more significant in aqueous extract. Quantitative analysis was carried out using TLC method by different solvent system. Amongst various solvent systems, Butanol: acetic acid: water (9: 0.9: 0.1 v/v/v) shows maximum resolution and number of spots produced at long UV (365 nm) and under iodine vapours. The TLC chromatograms constituted different coloured phytochemical compounds with different Rf values. It can be conveniently used to evaluate the quality of different area samples. This indicates that the leaves can be useful for treating different diseases because the therapeutic activity of a plant is due to the presence of particular class of compounds and thus can serve as potential sources of useful drugs in future.


2008 ◽  
Vol 16 (8) ◽  
pp. 483-500 ◽  
Author(s):  
Jianqing Zhao ◽  
Yi Fu ◽  
Shumei Liu

Polyhedral oligomeric silsesquioxane (POSS) nanoparticles have been successfully incorporated into thermoplastic and thermoset polymers via copolymerization, grafting, blending, surface bonding, or other transformations. A great promise in the development of a wide range of POSS-containing nanocomposites with diversely improved properties has been displayed. Thermal properties, viscoelastic properties, mechanical strengths, dielectric constants, surface hydrophobicity and flame-retardancy of the nanocomposites are easily varied to target properties by adjusting POSS structure, crosslink density, processing condition, etc. Investigations on the effects of POSS molecular geometry, composition, and concentration on physical and mechanical properties of resultant POSS-modified thermoplastic and thermosetting nanocomposites have been carefully reviewed in this article.


Blood ◽  
2020 ◽  
Vol 136 (22) ◽  
pp. 2535-2547 ◽  
Author(s):  
W. Grey ◽  
R. Chauhan ◽  
M. Piganeau ◽  
H. Huerga Encabo ◽  
M. Garcia-Albornoz ◽  
...  

Abstract Expansion of human hematopoietic stem cells (HSCs) is a rapidly advancing field showing great promise for clinical applications. Recent evidence has implicated the nervous system and glial family ligands (GFLs) as potential drivers of hematopoietic survival and self-renewal in the bone marrow niche; how to apply this process to HSC maintenance and expansion has yet to be explored. We show a role for the GFL receptor, RET, at the cell surface of HSCs in mediating sustained cellular growth, resistance to stress, and improved cell survival throughout in vitro expansion. HSCs treated with the key RET ligand/coreceptor complex, glial-derived neurotrophic factor and its coreceptor, exhibit improved progenitor function at primary transplantation and improved long-term HSC function at secondary transplantation. Finally, we show that RET drives a multifaceted intracellular signaling pathway, including key signaling intermediates protein kinase B, extracellular signal-regulated kinase 1/2, NF-κB, and p53, responsible for a wide range of cellular and genetic responses that improve cell growth and survival under culture conditions.


2021 ◽  
Author(s):  
Sanghamitra Das ◽  
Taraprasanna Dash ◽  
Devika Jena ◽  
Eleena Mohapatra ◽  
C K Maiti

Abstract In this work, we present a physics-based analysis of two-dimensional electron gas (2DEG) sheet carrier density and other microwave characteristics such as transconductance and cutoff frequency of AlxGa1-xN/GaN high electron mobility transistors (HEMT). An accurate polarization-dependent charge control-based analysis is performed for microwave performance assessment in terms of current, transconductance, gate capacitances, and cutoff frequency of lattice-mismatched AlGaN/GaN HEMTs. The influence of stress on spontaneous and piezoelectric polarization is included in the simulation of an AlGaN/GaN HEMT. We have shown the change in threshold voltage (Vt) due to tensile and compressive strain with different gate lengths. Also, the influence of stress due to the change in nitride thickness is presented. Our simulation results for drain current, transconductance, and current-gain cutoff frequency for various gate length devices are calibrated and verified with experimental data over a wide range of gate and drain applied voltages, which are expected to be useful for microwave circuit design. The predicted transconductance, drain conductance, and operation frequency are quite close to the experimental data. The AlGaN/GaN heterostructure HEMTs with nitride passivation layers show great promise as a candidate in future high speed and high power applications.


Author(s):  
Andrea G. Sanvito ◽  
Giacomo Persico ◽  
M. Sergio Campobasso

Abstract This study provides a novel contribution toward the establishment of a new high-fidelity simulation-based design methodology for stall-regulated horizontal axis wind turbines. The aerodynamic design of these machines is complex, due to the difficulty of reliably predicting stall onset and poststall characteristics. Low-fidelity design methods, widely used in industry, are computationally efficient, but are often affected by significant uncertainty. Conversely, Navier–Stokes computational fluid dynamics (CFD) can reduce such uncertainty, resulting in lower development costs by reducing the need of field testing of designs not fit for purpose. Here, the compressible CFD research code COSA is used to assess the performance of two alternative designs of a 13-m stall-regulated rotor over a wide range of operating conditions. Validation of the numerical methodology is based on thorough comparisons of novel simulations and measured data of the National Renewable Energy Laboratory (NREL) phase VI turbine rotor, and one of the two industrial rotor designs. An excellent agreement is found in all cases. All simulations of the two industrial rotors are time-dependent, to capture the unsteadiness associated with stall which occurs at most wind speeds. The two designs are cross-compared, with emphasis on the different stall patterns resulting from particular design choices. The key novelty of this work is the CFD-based assessment of the correlation among turbine power, blade aerodynamics, and blade design variables (airfoil geometry, blade planform, and twist) over most operational wind speeds.


2007 ◽  
Vol 60 ◽  
pp. 155-178
Author(s):  
Marya Schechtman

Everyone loves a good story. But does everyone live a good story? It has frequently been asserted by philosophers, psychologists and others interested in understanding the distinctive nature of human existence that our lives do, or should, take a narrative form. Over the last few decades there has been a steady and growing focus on this narrative approach within philosophical discussions of personal identity, resulting in a wide range of narrative identity theories. While the narrative approach has shown great promise as a tool for addressing longstanding and intractable problems of personal identity, it has also given rise to much suspicion. Opponents of this approach charge it with overstating or distorting the structure of actual lives.


2020 ◽  
Vol 12 (14) ◽  
pp. 2279 ◽  
Author(s):  
Shekh Md Mahmudul Islam ◽  
Olga Borić-Lubecke ◽  
Yao Zheng ◽  
Victor M. Lubecke

Non-contact vital signs monitoring using microwave Doppler radar has shown great promise in healthcare applications. Recently, this unobtrusive form of physiological sensing has also been gaining attention for its potential for continuous identity authentication, which can reduce the vulnerability of traditional one-pass validation authentication systems. Physiological Doppler radar is an attractive approach for continuous identity authentication as it requires neither contact nor line-of-sight and does not give rise to privacy concerns associated with video imaging. This paper presents a review of recent advances in radar-based identity authentication systems. It includes an evaluation of the applicability of different research efforts in authentication using respiratory patterns and heart-based dynamics. It also identifies aspects of future research required to address remaining challenges in applying unobtrusive respiration-based or heart-based identity authentication to practical systems. With the advancement of machine learning and artificial intelligence, radar-based continuous authentication can grow to serve a wide range of valuable functions in society.


1985 ◽  
Vol 112 ◽  
pp. 385-390
Author(s):  
D. Kent Cullers

The NASA Multichannel Spectrum Analyzer (MCSA) supplies data in several formats and in a wide range of frequency resolutions. To decide if an extraterrestrial signal is present, this data is searched using detection algorithms particularly sensitive to signals concentrated in frequency and/or time. The algorithms, whose ultimate sensitivities are determined by theoretical considerations, are also constrained by available computing power. At present, practical detection of repetitive pulses is possible at an average power about five times lower than that for incoherent CW detection. After a period of field testing, the best detection algorithms, presently implemented in software, will be converted to hardware to increase their speed.


Sensors ◽  
2019 ◽  
Vol 19 (8) ◽  
pp. 1853 ◽  
Author(s):  
Stefano Alvisi ◽  
Francesco Casellato ◽  
Marco Franchini ◽  
Marco Govoni ◽  
Chiara Luciani ◽  
...  

While smart metering applications have initially focused on energy and gas utility markets, water consumption has recently become the subject of increasing attention. Unfortunately, despite the large number of solutions available on the market, the lack of an open and widely accepted communication standard means that vendors typically propose proprietary data collection solutions whose adoption causes non-trivial problems to water utility companies in term of costs, vendor lock-in, and lack of control on the data collection infrastructure. There is the need for open and interoperable smart water metering solutions, capable of collecting data from the wide range of water meters on the market. This paper reports our experience in the development and field testing of a highly interoperable smart water metering solution, which we designed in collaboration with several water utility companies and which we deployed in Gorino Ferrarese, Italy, in collaboration with CADF (Consorzio Acque Delta Ferrarese), the water utility serving the city. At the core of our solution is SWaMM (Smart Water Metering Middleware), an interoperable wireless IoT middleware based on the Edge computing paradigm, which proved extremely effective in interfacing with several types of smart water meters operating with different protocols.


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