Upper Grand Coulee: New views of a channeled scabland megafloods enigma

2021 ◽  
pp. 245-300
Author(s):  
Richard B. Waitt* ◽  
Brian F. Atwater ◽  
Karin Lehnigk ◽  
Isaac J. Larsen ◽  
Bruce N. Bjornstad ◽  
...  

ABSTRACT New findings about old puzzles occasion rethinking of the Grand Coulee, greatest of the scabland channels. Those puzzles begin with antecedents of current upper Grand Coulee. By a recent interpretation, the upper coulee exploited the former high-level valley of a preflood trunk stream that had drained to the southwest beside and across Coulee anticline or monocline. In any case, a constriction and sharp bend in nearby Columbia valley steered Missoula floods this direction. Completion of upper Grand Coulee by megaflood erosion captured flood drainage that would otherwise have continued to enlarge Moses Coulee. Upstream in the Sanpoil valley, deposits and shorelines of last-glacial Lake Columbia varied with the lake’s Grand Coulee outlet while also recording scores of Missoula floods. The Sanpoil evidence implies that upper Grand Coulee had approached its present intake depth early the last glaciation at latest, or more simply during a prior glaciation. An upper part of the Sanpoil section provides varve counts between the last tens of Missoula floods in a stratigraphic sequence that may now be linked to flood rhythmites of southern Washington by a set-S tephra from Mount St. Helens. On the floor of upper Grand Coulee itself, recently found striated rock and lodgement till confirm the long-held view, which Bretz and Flint had shared, that cutting of upper Grand Coulee preceded its last-glacial occupation by the Okanogan ice lobe. A dozen or more late Missoula floods registered as sand and silt in the lee of Steamboat Rock. Some of this field evidence about upper Grand Coulee may conflict with results of recent two-dimensional simulations for a maximum Lake Missoula. In these simulations only a barrier high above the present coulee intake enables floods to approach high-water marks near Wenatchee that predate stable blockage of Columbia valley by the Okanogan lobe. Above the walls of upper Grand Coulee, scabland limits provide high-water targets for two-dimensional simulations of watery floods. The recent models sharpen focus on water sources, prior coulee incision, and coulee’s occupation by the Okanogan ice lobe. Field reappraisal continues downstream from Grand Coulee on Ephrata fan. There, some of the floods exiting lower Grand Coulee had bulked up with fine sediment from glacial Lake Columbia, upper coulee till, and a lower coulee lake that the fan itself impounded. Floods thus of debris-flow consistency carried outsize boulders previously thought transported by watery floods. Below Ephrata fan, a backflooded reach of Columbia valley received Grand Coulee outflow of small, late Missoula floods. These late floods can—by varve counts in post-S-ash deposits of Sanpoil valley—be clocked now as a decade or less apart. Still farther downstream, Columbia River gorge choked the largest Missoula floods, passing peak discharge only one-third to one-half that released by the breached Lake Missoula ice dam.

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 412
Author(s):  
Sam Swingler ◽  
Abhishek Gupta ◽  
Hazel Gibson ◽  
Marek Kowalczuk ◽  
Wayne Heaselgrave ◽  
...  

Bacterial cellulose (BC) is an extracellular polymer produced by Komagateibacter xylinus, which has been shown to possess a multitude of properties, which makes it innately useful as a next-generation biopolymer. The structure of BC is comprised of glucose monomer units polymerised by cellulose synthase in β-1-4 glucan chains which form uniaxially orientated BC fibril bundles which measure 3–8 nm in diameter. BC is chemically identical to vegetal cellulose. However, when BC is compared with other natural or synthetic analogues, it shows a much higher performance in biomedical applications, potable treatment, nano-filters and functional applications. The main reason for this superiority is due to the high level of chemical purity, nano-fibrillar matrix and crystallinity. Upon using BC as a carrier or scaffold with other materials, unique and novel characteristics can be observed, which are all relatable to the features of BC. These properties, which include high tensile strength, high water holding capabilities and microfibrillar matrices, coupled with the overall physicochemical assets of bacterial cellulose makes it an ideal candidate for further scientific research into biopolymer development. This review thoroughly explores several areas in which BC is being investigated, ranging from biomedical applications to electronic applications, with a focus on the use as a next-generation wound dressing. The purpose of this review is to consolidate and discuss the most recent advancements in the applications of bacterial cellulose, primarily in biomedicine, but also in biotechnology.


2021 ◽  
pp. 0308518X2199781
Author(s):  
Xinyue Luo ◽  
Mingxing Chen

The nodes and links in urban networks are usually presented in a two-dimensional(2D) view. The co-occurrence of nodes and links can also be realized from a three-dimensional(3D) perspective to make the characteristics of urban network more intuitively revealed. Our result shows that the external connections of high-level cities are mainly affected by the level of cities(nodes) and less affected by geographical distance, while medium-level cities are affected by the interaction of the level of cities(nodes) and geographical distance. The external connections of low-level cities are greatly restricted by geographical distance.


2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Myung Eun Suk

Abstract Recent advances in the development of two-dimensional (2D) materials have facilitated a wide variety of surface chemical characteristics obtained by composing atomic species, pore functionalization, etc. The present study focused on how chemical characteristics such as hydrophilicity affects the water transport rate in hexagonal 2D membranes. The membrane–water interaction strength was tuned to change the hydrophilicity, and the sub-nanometer pore was used to investigate single-file flux, which is known to retain excellent salt rejection. Due to the dewetting behavior of the hydrophobic pore, the water flux was zero or nominal below the threshold interaction strength. Above the threshold interaction strength, water flux decreased with an increase in interaction strength. From the potential of mean force analysis and diffusion coefficient calculations, the proximal region of the pore entrance was found to be the dominant factor degrading water flux at the highly hydrophilic pore. Furthermore, the superiority of 2D membranes over 3D membranes appeared to depend on the interaction strength. The present findings will have implications in the design of 2D membranes to retain a high water filtration rate.


1993 ◽  
Vol 39 (131) ◽  
pp. 45-49 ◽  
Author(s):  
André Berger ◽  
Hubert Gallée ◽  
Christian Tricot

Abstract A two-dimensional model which links the atmosphere, the mixed layer of the ocean, the sea ice, the continents, the ice sheets and their underlying bedrock has been used to test the Milankovitch theory over the last glacial—interglacial cycle. It was found that the orbital variations alone can induce, in such a system, feed-backs sufficient to generate the low-frequency part of the climatic variations over the last 122 kyear. These simulated variations at the astronomical time-scale are broadly in agreement with ice volume and sea-level reconstructions independently obtained from geological data. Imperfections in the simulated climate were the insufficient southward extent of the ice sheets and the too small hemispheric cooling during the last glacial maximum. These deficiencies were partly remedied in a further experiment (Gallée and others, in press) by using the time-dependent CO2 atmospheric concentration given by the Vostok ice core in addition to the astronomical forcing. For this second experiment, the main mechanisms and feedbacks responsible for the glaciation and the deglaciation in the model are discussed here.


2002 ◽  
Vol 17 (7) ◽  
pp. 697-706 ◽  
Author(s):  
Brenda L. Hall ◽  
George H. Denton ◽  
Bret Overturf ◽  
Chris H. Hendy

1964 ◽  
Vol 42 ◽  
pp. 1-104
Author(s):  
E.I Hamilton

The Ilímaussaq intrusion (S.W. Greenland) was emplaced into granitic Precambrian basement rocks. The intrusion is of a highly alkaline nature and in terms of rocks types, its major-, minor- and trace elements, may be compared to the Khibina-Lovozero intrusion of the Kola Peninsula, U.S.S.R. The present paper describes the geochemistry of the northern part of the intrusion and the marginal rocks. New total rock analyses are given together with the detailed geochemistry of U, Th, Radioactivity, Nb, Rb, Li and Be. The Ilímaussaq intrusion consists of an early augite syenite chilled against the country rocks. The augite syenite forms a more or less continuous ring around and above the intrusion. The main central mass of the intrusion consists of poorly layered, very coarse-grained, Na-rich "foyaite" containing relatively large amounts of sodalite and eudialyte. Differentiation of the "foyaite magma" gave rise to a volatile rich residual liquid from which lujavrites were formed. Differentiation of the lujavrites in the central area of the intrusion resulted in a lower banded sequence, the kakortokites, and an upper lujavrite liquid. When the confining pressure was exceeded, explosive brecciation occurred and lujavrite was intruded into the surrounding rocks. At a high level in the intrusion a sheet-like body of soda granite was emplaced together with various quart-bearing syenites. The relative time of intrusion of the quartz-bearing syenite is uncertain through lack of field evidence. Emplacement of the early augite syenite may be related to ring faulting followed by cauldron subsidence. The later Na-rich rocks may have replaced the earlier layered augite syenite or have been emplaced into a "magma chamber" developed by cauldron subsidence. The Na-Zr-Cl-rich rocks show evidence of cooling inwards with the development of a central volatile-rich pocket. The Ilímaussaq rocks probably represent a final highly fractionated stage of the more normal augite syenite magma common to the S. W. Greenland alkaline province.


Author(s):  
Wael Toghuj ◽  
Ghazi I. Alkhatib

Digital communication systems are an important part of modern society, and they rely on computers and networks to achieve critical tasks. Critical tasks require systems with a high level of reliability that can provide continuous correct operations. This paper presents a new algorithm for data encoding and decoding using a two-dimensional code that can be implemented in digital communication systems, electronic memories (DRAMs and SRAMs), and web engineering. The developed algorithms correct three errors in codeword and detect four, reaching an acceptable performance level. The program that is based on these algorithms enables the modeling of error detection and correction processes, optimizes the redundancy of the code, monitors the decoding procedures, and defines the speed of execution. The performance of the derived code improves error detection and correction over the classical code and with less complexity. Several extensible applications of the algorithms are also given.


Author(s):  
Wael Toghuj ◽  
Ghazi I. Alkhatib

Digital communication systems are an important part of modern society, and they rely on computers and networks to achieve critical tasks. Critical tasks require systems with a high level of reliability that can provide continuous correct operations. This paper presents a new algorithm for data encoding and decoding using a two-dimensional code that can be implemented in digital communication systems, electronic memories (DRAMs and SRAMs), and web engineering. The developed algorithms correct three errors in codeword and detect four, reaching an acceptable performance level. The program that is based on these algorithms enables the modeling of error detection and correction processes, optimizes the redundancy of the code, monitors the decoding procedures, and defines the speed of execution. The performance of the derived code improves error detection and correction over the classical code and with less complexity. Several extensible applications of the algorithms are also given.


2018 ◽  
Vol 06 (04) ◽  
pp. 1850023 ◽  
Author(s):  
Xifeng WANG

Most of the existing studies on regional water resources efficiency only consider the total regional water use while ignoring the regional endowment. Therefore, it is essential to introduce the water resources carrying capacity into the study. Given that data envelopment analysis (DEA) cannot compare the time series of a single decision-making unit, we employ the DEA-window analysis to study China’s water resources efficiency during 2005–2012 with the regional carrying capacity being considered, and analyze the spatiotemporal evolution. The study shows that such efficiency has increased from 0.71 in 2005 to 0.79 in 2012. High water resources efficiency is observed in Liaoning, Tibet, Yunnan, Beijing, Tianjin, Shanghai, Jiangsu, Zhejiang, Guangdong and Sichuan, where the output levels and utilization ratios of water resources are positively correlated. Low water resources efficiency is observed in Henan, Shaanxi, Gansu, Ningxia and Xinjiang which feature high-level utilization and low carrying capacity of water resources. As for regional water resources efficiency, eastern and southern coastal regions rank first, followed by Northeast China and northern coastal regions, southwest and northwest regions of China and lastly the middle reaches of the Yellow and Yangtze Rivers. Therefore, policy-makers should not only accord the regional development with carrying capacity, but also enhance cross-regional industrial cooperation for coordinated development.


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