On the impact of traffic burst on performances of high capacity cellular systems

Author(s):  
G. Falciasecca ◽  
M. Frullone ◽  
G. Riva ◽  
A.M. Serra
1997 ◽  
Vol 35 (8) ◽  
pp. 38-45 ◽  
Author(s):  
M. Madfors ◽  
K. Wallstedt ◽  
S. Magnusson ◽  
H. Olofsson ◽  
P.-O. Backman ◽  
...  

2017 ◽  
pp. 278-284
Author(s):  
Oleksandr Khokhotva

Landfills are widely used for the disposal of households' and industrial waste. Liquid landfill effluents contain heavy metals, are toxic to humans and ecosystems and have to be efficiently treated. One treatment option that is becoming popular is the reactive filter technology. The total efficiency of metal removal by a filter media greatly depends not only on adsorption itself, but also on the metal leaching from the adsorbent. The last parameter, in turn, may be dependant on changing environmental conditions since filters are usually located on open air and flow of contaminated water (landfill leachate, runoff water) has the intermittent nature. A filter material may dry, become frozen or stay wet, depending on a season. Previously adsorbed metals can leach from an adsorbent at the next flash of water, coming to water treatment facilities. Among others, pine bark has shown a high capacity to adsorb heavy metals from landfill leachates. In this study, pine bark has been pre-treated with urea-solution in order to increase its stability and adsorption properties. Within leaching experiments using either non-treated or pre-treated bark samples no significant influence of the changing environmental conditions on the extent of metal leaching was observed, though in most cases, metal leaching from wet bark samples exposed to freezing was somewhat higher. Zn leaching was the highest and Cu leaching the lowest for both NTB and UTB samples. The metal leaching from non-treated bark was several-fold higher compared to urea-treated bark. Possible mechanisms of barkurea interactions and reasons for enhanced metals adsorption by urea-modified bark are discussed.


2021 ◽  
Author(s):  
Anuj K Yadav ◽  
Michael C. Lee ◽  
Melissa Lucero ◽  
Christopher J. Reinhardt ◽  
ShengZhang Su ◽  
...  

<p>Nitric oxide (NO) plays a critical role in acute and chronic inflammation. NO’s contributions to cancer are of particular interest due to its context-dependent bioactivities. For example, immune cells initially produce cytotoxic quantities of NO in response to the nascent tumor. However, it is believed that this fades over time and reaches a concentration that supports the tumor microenvironment (TME). These complex dynamics are further complicated by other factors, such as diet and oxygenation, making it challenging to establish a complete picture of NO’s impact on tumor progression. Although many activity-based sensing (ABS) probes for NO have been developed, only a small fraction have been employed <i>in vivo </i>and fewer yet are practical in cancer models where the NO concentration is < 200 nM. To overcome this outstanding challenge, we have developed BL<sub>660</sub>-NO, the first ABS probe for NIR bioluminescence imaging of NO in cancer. Owing to the low intrinsic background, high sensitivity, and deep tissue imaging capabilities of our design, BL<sub>660</sub>-NO was successfully employed to visualize endogenous NO in cellular systems, a human liver metastasis model, and a murine breast cancer model. Importantly, its exceptional performance facilitated the design of a dietary study to examine the impact of NO on the TME by varying the intake of fat. BL<sub>660</sub>-NO provides the first direct molecular evidence that intratumoral NO becomes elevated in mice fed a high-fat diet who became obese with larger tumors compared to control animals on a low-fat diet. These results indicate that an inflammatory diet can increase NO production via recruitment of macrophages and overexpression of iNOS which in turn can drive tumor progression.<br></p>


Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3554
Author(s):  
Naushath M. Haleem ◽  
Athula D. Rajapakse ◽  
Aniruddha M. Gole ◽  
Ioni T. Fernando

A selective fault clearing scheme is proposed for a hybrid voltage source converter (VSC)-line commutated converter (LCC) multi-terminal high voltage direct current (HVdc) transmission structure in which two small capacity VSC stations tap into the main transmission line of a high capacity LCC-HVdc link. The use of dc circuit breakers (dc CBs) on the branches connecting to VSCs at the tapping points is explored to minimize the impact of tapping on the reliability of the main LCC link. This arrangement allows clearing of temporary faults on the main LCC line as usual by force retardation of the LCC rectifier. The faults on the branches connecting to VSC stations can be cleared by blocking insulated gate bipolar transistors (IGBTs) and opening ac circuit breakers (ac CB), without affecting the main line’s performance. A local voltage and current measurement based fault discrimination scheme is developed to identify the faulted sections and pole(s), and trigger appropriate fault recovery functions. This fault discrimination scheme is capable of detecting and discriminating short circuits and high resistances faults in any branch well before 2 ms. For the test grid considered, 6 kA, 2 ms dc CBs can easily facilitate the intended fault clearing functions and maintain the power transfer through healthy pole during single-pole faults.


2012 ◽  
Vol 6 (1) ◽  
Author(s):  
Shijia Zhao ◽  
Xiangyi (Cheryl) Liu ◽  
Linxia Gu

Braided wire stents demonstrate distinct characteristics compared to welded ones. In this study, both braided and welded wire stents with the same nominal dimensions were crimped inside a sheath and then deployed into a stenosed artery using finite element analysis. The braided wire stent was generated by overlapping wires to form crisscross shape. A welded wire stent was created by welding the intersection points of wires to avoid sliding between wires. The effect of fabrication technique on mechanical behavior of Nitinol wire stents was evaluated. The results showed that relative sliding between wires reduced the deformation of the braided stent, which led to less radial strength than the welded one; therefore, the deployed braided stent was more conformed to the anatomic shape of the lesion and much less efficient for restoring the patency of the stenotic artery. Post balloon-dilation was commonly used to improve its performance in terms of lumen gain and deployed shape of the stent. On the contrary, the welded wire stent exhibited a high capacity for pushing the occlusion outward. It reached an approximately uniform shape after deployment. The welded joints caused larger deformation and high strain on the stent struts, which indicate a potential earlier failure for the welded stent. In addition, higher contact pressure at the stent-lesion interface and higher arterial stresses were observed in the artery supported by the welded stent. The peak stress concentration may increase the occurrence of neointimal hyperplasia.


Author(s):  
Y. A. Bahei-El-Din ◽  
M. A. Zikry ◽  
A. Rajendran

The deformation fields and kinematics of woven composite material systems due to impact loads are analyzed and characterized for various structural parameters. Target plates comprised of woven composites with 3D preforms are considered. The analysis examines fully consolidated as well as cellular systems and simulates actual experiments. Solution of the nonlinear dynamic/contact problem was obtained by a meso-mechanics based finite element model. The results quantify experimental observations, which reveal distinct behavior under impact among nonporous and porous systems. It was found that wave propagation effects at incident energies in the order of 500 J are significant and lead to penetration at the impact face. Localized shear damage in the 3D woven system precede penetration in both the nonporous and the porous systems. The porous system is capable of dissipating more energy prior to penetration due to containment of local damage, which emanates from the void boundaries, within subsurface locations.


Author(s):  
David Tibbetts ◽  
Nicholas Dale

Marine installation operations are becoming ever longer, larger and deeper. With campaigns regularly being carried out in the 2,000–3,000m water depth range and tieback lengths on the increase; installation, replacement or recovery works for this specification of product requires specialist equipment that can accommodate the increasing bulk of the flexible products being installed, without compromising the performance of the vessels which carry them. In order to fulfil this technical challenge, new and innovative carousel designs are being developed. Placing the ‘reel’ horizontally allows maximum product capacity whilst minimising the impact on the vessel, thus maintaining operational efficiency in both shallow and deep waters and for projects such as subsea tiebacks and connections to processing platforms and offshore installations. This paper explores recent developments in technology, where product loads of up to 1,500Te (Tonnes) are frequently required and ever shorter schedules are placed on contractors for initial spooling and subsequent installation. Technical innovations, operational solutions and commercial advantages will be assessed and the ability to open up new markets with the technology on offer will be scrutinised. Alongside this, the benefits of modularity are evaluated to quantify the advantages of being able to disassemble and transport this type of hardware worldwide and the vessel utilisation improvements that can be made.


2009 ◽  
Vol 15 (2) ◽  
pp. 161-183 ◽  
Author(s):  
Tim Andersen ◽  
Richard Newman ◽  
Tim Otter

We have constructed a computational platform suitable for examining emergence of shape homeostasis in simple three-dimensional cellular systems. An embryo phenotype results from a developmental process starting with a single cell and its genome. When coupled to an evolutionary search, this platform can evolve embryos with particular stable shapes and high capacity for self-repair, even though repair is not genetically encoded or part of the fitness criteria. With respect to the genome, embryo shape and self-repair are emergent properties that arise from complex interactions among cells and cellular components via signaling and gene regulatory networks, during development or during repair. This report analyzes these networks and the underlying mechanisms that control embryo growth, organization, stability, and robustness to injury.


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