Traveling waves in lattice differential equations with distributed maturation delay

In this paper we derive a lattice model with infinite distributed delay to describe the growth of a single-species population in a 2D patchy environment with infinite number of patches connected locally by diffusion and global interaction. We consider the existence of traveling wave solutions when the birth rate is large enough that each patch can sustain a positive equilibrium. When the birth function is monotone, we prove that there exists a traveling wave solution connecting two equilibria with wave speed $c>c^*(\theta)$ by using the monotone iterative method and super and subsolution technique, where $\theta\in [0,2\pi]$ is any fixed direction of propagation. When the birth function is non-monotone, we prove the existence of non-trivial traveling wave solutions by constructing two auxiliary systems satisfying quasi-monotonicity

Study of Charging Nitrogen to External Floating Roof Tank to Prevent Rim-seal Fires from Lightning

AbstractIt is estimated that 95% of rim seal fires are caused by lightning strikes. To avoid rim-seal fires caused by lightning, the existing methods mainly focus on the use of secondary sealing to reduce volatilization of oil and the electrical connections measures such as air terminals, deflectors, grounding device, discharge shunts and scalable grounding device to avoid sparks caused by lightning current. But these devices can’t eliminate the spark generation thoroughly. A new method charging nitrogen to external floating roof tank seal ring is proposed to prevent rim-seal fires from lightning. In this paper, the safe oxygen content is set as the goal to charge nitrogen. An annular nitrogen charging pipe network is designed and its reliability is verified by experiment. The time of filling nitrogen to the seal ring of an external floating roof tank with the capacity of 10×104 m3 at the rate of 63.38 m3/h to reach the nitrogen charging goal is proved within the time of lightning warning through experiment. And this experiment can provide some reference to the application of nitrogen charging

THE INTELLECTUAL CAPITAL AND JOURNALISTS\u27 PERFORMANCE

In the age of knowledge-based economy, intellectual capital (IC) is of growing and substantial importance more so than the tangible assets such as land and financial capital. IC includes human capital, organizational capital and social capital. IC has become a driving force for an organization to stay competitive. Journalists are vital human capital in a news organization. They are the knowledge workers who need both independence (autonomy) and interdependence (teamwork) in order to accumulate and share knowledge. In addition to playing the role as \u27gate-keepers\u27 in the information delivery process, part of a journalist\u27s job is to develop relationships with news sources from outside of the organization. Therefore, journalists are also the social capital in their organization. A news organization loses both human and social capital whenever a journalist resigns or job-hops. The purpose of this research is to examine relationships between IC and journalists? performance in the media. We argue that journalists embody both human and social capitals which are mediated by job autonomy which journalists need in order to achieve high individual job performance. We also argue that organizational capital is mediated by team-level task interdependence which also leads to better individual job performance

6,6′-Dimethyl-2,2′-[oxalylbis(aza­nedi­yl)]dipyridinium dichloride acetonitrile solvate

In the crystal structure of the title compound, C14H16N4O2 2+·2Cl−·CH3CN, weak inter­molecular N—H⋯Cl hydrogen bonds are found between the H atoms bound to the pyridine and amine N atoms and the chloride anions. The asymmetric unit consits of one half cationic mol­ecule which is located on a centre of inversion, one chloride anion in a general position and one half acetonitrile mol­ecule which is located on a twofold axis. Because of symmetry, the C—H hydrogens of the acetonitrile solvent mol­ecule are disordered over two orientations

ENAT-PT: An Enhanced NAT-PT Model

NAT-PT would allow IPv4 nodes to communicate with IPv6 nodes transparently by translating the IPv6 address into a registered V4 address. However, NAT-PT would fall flat when the pool of V4 addresses is exhausted. NAPT-PT multiplexes the registered address’ ports and will allow for a maximum of 63K outbound TCP and 63K UDP sessions per IPv4 address, but it is unidirectional. We present in this paper a novel solution ENAT-PT（an enhanced NAT-PT），which will allow for a great number of inbound sessions by using a single V4 address. By using ENAT-PT, we can visit V6 networks from a V4 network with a small address pool

Intraluminal duodenal diverticulum in a child concomitant with an entrapped coin and a duodenal polyp

SummaryIntraluminal duodenal diverticulum (IDD) is a rare congenital anomaly. We present the report of an 8-year-old girl who had an entrapped coin in an IDD for 3 years that was associated with recurrent pancreatitis. Besides, a duodenoduodenal intussusception was found during the course of investigation and it seemed that a concomitant duodenal polyp contributed to the development of the intussusception. In view of the rarity of each of the aforementioned situations and the improbability of these conditions occurring together, this unusual and possibly unique case is therefore reported here

Control of Formation-Flying Multi-Element Space Interferometers with Direct Interferometer-Output Feedback

The long-baseline space interferometer concept involving formation flying of multiple spacecrafts holds great promise as future space missions for high-resolution imagery. A major challenge of obtaining high-quality interferometric synthesized images from long-baseline space interferometers is to accurately control these spacecraft and their optics payloads in the specified configuration. Our research focuses on the determination of the optical errors to achieve fine control of long-baseline space interferometers without resorting to additional sensing equipment. We present a suite of estimation tools that can effectively extract from the raw interferometric image relative x/y, piston translational and tip/tilt deviations at the exit pupil aperture. The use of these error estimates in achieving control of the interferometer elements is demonstrated using simulated as well as laboratory-collected interferometric stellar images

Control of Formation-Flying Multi-Element Space Interferometers with Direct Interferometer-Output Feedback

The long-baseline space interferometer concept involving formation flying of multiple spacecraft holds great promise as future space missions for high-resolution imagery. A major challenge of obtaining high-quality interferometric synthesized images from long-baseline space interferometers is to accurately control these spacecraft and their optics payloads in the specified configuration. Our research focuses on the determination of the optical errors to achieve fine control of long-baseline space interferometers without resorting to additional sensing equipment. We present a suite of estimation tools that can effectively extract from the raw interferometric image relative x/y, piston translational and tip/tilt deviations at the exit pupil aperture. The use of these error estimates in achieving control of the interferometer elements is demonstrated using simulated as well as laboratory-collected interferometric stellar images

N-(6-Methyl-2-pyrid­yl)formamide

The mol­ecule of the title compound, C7H8N2O, is essentially planar with a maximum deviation of 0.0439 (1) Å from the best plane. In the crystal, N—H⋯O hydrogen bonds between self-complementary amide groups join mol­ecules into centrosymmetric dimers