Evidence for gas hydrate occurrences in the Canadian Arctic Beaufort Sea within permafrost-associated shelf and deep-water marine environments

Riedel, M.,Brent, T.A.,Taylor, G.,Taylor, A.E.,Hong, J.-K.,Jin, Y.-K.,Dallimore, S.R. Elsevier 2017 Marine and petroleum geology Vol.81 No.-

<P><B>Abstract</B></P> <P>The presence of a wedge of offshore permafrost on the shelf of the Canadian Beaufort Sea has been previously recognized and the consequence of a prolonged occurrence of such permafrost is the possibility of an underlying gas hydrate regime. We present the first evidence for wide-spread occurrences of gas hydrates across the shelf in water depths of 60–100 m using 3D and 2D multichannel seismic (MCS) data. A reflection with a polarity opposite to the seafloor was identified ∼1000 m below the seafloor that mimics some of the bottom-simulating reflections (BSRs) in marine gas hydrate regimes. However, the reflection is not truly bottom-simulating, as its depth is controlled by offshore permafrost. The depth of the reflection decreases with increasing water depth, as predicted from thermal modeling of the late Wisconsin transgression. The reflection crosscuts strata and defines a zone of enhanced reflectivity beneath it, which originates from free gas accumulated at the phase boundary over time as permafrost and associated gas hydrate stability zones thin in response to the transgression. The wide-spread gas hydrate occurrence beneath permafrost has implications on the region including drilling hazards associated with the presence of free gas, possible overpressure, lateral migration of fluids and expulsion at the seafloor. In contrast to the permafrost-associated gas hydrates, a deep-water marine BSR was also identified on MCS profiles. The MCS data show a polarity-reversed seismic reflection associated with a low-velocity zone beneath it. The seismic data coverage in the southern Beaufort Sea shows that the deep-water marine BSR is not uniformly present across the entire region. The regional discrepancy of the BSR occurrence between the US Alaska portion and the Mackenzie Delta region may be a result of high sedimentation rates expected for the central Mackenzie delta and high abundance of mass-transport deposits that prohibit gas to accumulate within and beneath the gas hydrate stability zone.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Discovery of permafrost related gas hydrate regime in Beaufort shelf region. </LI> <LI> Base of gas hydrate stability zone follows trend predicted by thermal modelling. </LI> <LI> Permafrost-associated gas hydrate regime poses geo-hazards to drilling. </LI> <LI> Deep-water marine hydrate regime appears irregular across Beaufort margin. </LI> </UL> </P>

Food Safety Guidance on Different Toxicity End Points

Wolfram Riedel 한국식품영양과학회 2011 한국식품영양과학회 학술대회발표집 Vol.2011 No.10

Identifying ZVS Soft Switching Boundaries for Bi-Directional Dual Active Bridge DC-DC Converters using Frequency Domain Analysis

J. Riedel,D. G. Holmes,B. P. McGrath 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

Dual Active Bridge (DAB) converters offer an unmatched capability to transfer energy in either direction between two DC sources, while also providing galvanic isolation and high conversion efficiency. However, to operate at high efficiencies, the bridges must operate with Zero-Voltage-Switching (ZVS) over as wide an operating range as possible. The conventional approach to determine ZVS operation uses time domain analysis with ideal AC coupling inductances, which only approximately identifies the ZVS boundaries. This paper proposes a new approach using frequency domain analysis of the bridge switching patterns, which accurately predicts the ZVS boundaries over a full range of operating conditions while also accommodating more complex AC coupling structures and practical impedance non-idealities. An exact theoretical analysis is presented for two level modulation of the two bridges coupled through a general impedance structure. An analytical solution is then presented for a single coupling impedance, while boundaries for more complex coupling structures and practical impedances are solved by numerical integration. ZVS boundaries for selected systems are validated by matching simulation and experimental results.

로고스의 변증법 (Dialektik des Logos) 인가 : 고대초기철학에 관한 헤겔의 접근

M. Riedel,연효숙 한국헤겔학회 1986 헤겔연구 Vol.3 No.1

서독의 중소기업에 대한 기술정책

유르겐리들(Juergen Riedel) 한독경상학회 1986 經商論叢 Vol.4 No.-

N/A

WAVE MOTION IN A PLANAR CURVED BEAM

Bongsu Kang,Chris H. Riedel 한국소음진동공학회 2008 한국소음진동공학회 국제학술대회논문집 Vol.2008 No.7

울릉분지 서부 천부퇴적물에서의 가스 하이드레이트 생성과 부존

류병재,이영주,정부흥,M. Riedel,김지훈,R. Hyndman,김일수,박근필,정태진 대한지질학회 2004 대한지질학회 학술대회 Vol.2004 No.

A VARIANT OF THE QUADRATIC FUNCTIONAL EQUATION ON GROUPS AND AN APPLICATION

Elfen, Heather Hunt,Riedel, Thomas,Sahoo, Prasanna K. Korean Mathematical Society 2017 대한수학회보 Vol.54 No.6

Let G be a group and $\mathbb{C}$ the field of complex numbers. Suppose ${\sigma}:G{\rightarrow}G$ is an endomorphism satisfying ${{\sigma}}({{\sigma}}(x))=x$ for all x in G. In this paper, we first determine the central solution, f : G or $G{\times}G{\rightarrow}\mathbb{C}$, of the functional equation $f(xy)+f({\sigma}(y)x)=2f(x)+2f(y)$ for all $x,y{\in}G$, which is a variant of the quadratic functional equation. Using the central solution of this functional equation, we determine the general solution of the functional equation f(pr, qs) + f(sp, rq) = 2f(p, q) + 2f(r, s) for all $p,q,r,s{\in}G$, which is a variant of the equation f(pr, qs) + f(ps, qr) = 2f(p, q) + 2f(r, s) studied by Chung, Kannappan, Ng and Sahoo in [3] (see also [16]). Finally, we determine the solutions of this equation on the free groups generated by one element, the cyclic groups of order m, the symmetric groups of order m, and the dihedral groups of order 2m for $m{\geq}2$.

Gas hydrates in the Ulleung Basin, East Sea of Korea

Ryu, Byong-Jae,Riedel, Michael Chinese Geoscience Union 2017 TAO Vol.28 No.6

<P>To develop gas hydrates as a potential energy source, geophysical surveys and geological studies of gas hydrates in the Ulleung Basin, East Sea off the east coast of Korea have been carried out since 1997. Bottom-simulating reflector (BSR), initially used indicator for the potential presence of gas hydrates was first identified on seismic data acquired in 1998. Based on the early results of preliminary R&D project, 12367 km of 2D multichannel reflection seismic lines, 38 piston cores, and multi-beam echo-sounder data were collected from 2000 to 2004. The cores showed high amounts of total organic carbon and high residual hydrocarbon gas levels. Gas composition and isotope ratios define it as of primarily biogenic origin. In addition to the BSRs that are widespread across the basin, numerous chimney structures were found in seismic data. These features indicate a high potential of the Ulleung Basin to host significant amounts of gas hydrate. Dedicated geophysical surveys, geological and experimental studies were carried out culminating in two deep drilling expeditions, completed in 2007 and 2010. Sediment coring (including pressure coring), and a comprehensive well log program complements the regional studies and were used for a resource assessment. Two targets for a future test-production are currently proposed: pore-filling gas hydrate in sand-dominated sediments and massive occurrences of gas hydrate within chimney-like structures. An environmental impact study has been launched to evaluate any potential risks to production.</P>

Urban traffic control: present and the future

Xu Zhang,Thomas Riedel 서울시립대학교 도시과학연구원 2017 도시과학국제저널 Vol.21 No.2

Faced with the great stride of Information and Communication Technology (ICT), in particular in the utilization of the Internet and advances in data gathering methods, the application of the ICT in Transport and Traffic is getting ever more pervasive and is providing more opportunities in managing and controlling traffic more efficiently, equitably, flexibly and more dynamic in detecting and responding to varying traffic demand and environmental concerns. ICT is one of the best tools in assisting network management and control to achieve the most desirable network performance for these goals. As the behaviour of the road users can be influenced by the information received through V2X communication, how to incorporate the behavioural change especially with regard to speed advisory into the future control system is discussed in this paper. This paper first shows two real examples in China in coordinating traffic control to general green waves in large and complex networks to reduce journey time and fuel consumption, it then moves to briefly describe the simTD project conducted in Germany and the VS-PLUS controller used in the project. VS-PLUS is a parameterized control method, very flexible in meeting a variety of management and control objectives and to configure to deal with diverse traffic conditions. Its flexibility keeps it open to build a higher level of intelligence. Finally, the paper proposes to include vehicle speed as an endogenous parameter in optimizing traffic control and then introduces a Urban Traffic Control system configuration using the system jointly developed from a partnership between the Key Laboratory for the Ministry for Public Security of China for Optimal System Integration and Control at the Anhui Keli Information Industry Co. Ltd and the Verkehrs-Systeme AG of Switzerland.