2,330 research outputs found
Interview of Sayed Z. El-Sayed by Brian Shoemaker
No full textDr. Hussein Fausi, pp. 2
Professor Abdel Fatah Mohammed, pp. 2
Dr. Richard Van Cleef, pp. 3
Dr. Richard Flemming, pp. 3
Haupt ______, pp. 3
Ravel _______, pp. 3
Shepard ______, pp. 3
Claude du Bear, pp. 3
Walter Monk, pp. 3
Peter Ray, pp. 3
Captain Luis R. Capurro, pp. 6-7
Byunig Don Lee, pp. 8, 22
Dr. Martin Johnson, pp. 9
Captain Canepa, pp. 9-10
Larry Gould, pp. 10
______Zumberg, pp. 10
Lee Washbrun, pp. 10
George Llano, pp. 10, 15, 23-24, 30
Professor Mosby, pp. 12
Richard Thornton, pp. 13
_______Allsion McQueeny, pp. 15
Dr. Morita, pp. 15, 23
Claude Zumell, pp. 16
Holm Henson, pp. 16, 23
Larry Weber, pp. 19
_______Filchner, pp. 22
_______Shackelton, pp. 22
Mary Alice ________, pp. 22-23
George Knox, pp. 28
Dr. Numoto, pp. 29
Lou de Galle, pp. 29
Dick Laws, pp. 29, 37, 42, 64, 66
Joe Farnham, pp. 34, 63
Carol ________, pp. 35
Todd ________, pp. 40
Lubimora ______, pp. 40
Professor Bogdanor, pp. 41
__________ Kryzechevski, pp. 42
Barry Heywood, pp. 42, 65
David Drury, pp. 43
Martin Johnson, pp. 46
Carl Stegan, pp. 54
Sherwood Roland, pp. 55
Mario Mornina, pp. 55
Paul Ramsey, pp. 55-56
Bob Stephenson, pp. 60
Paul Skelly Powers, pp. 60
Charlie Inge, pp. 60
_________ Hovis, pp. 60
Emil Anderson, pp. 61
Admiral Bill Ramsey, pp. 62
Dean Stockwell, pp. 62
Bernard Stonehouse, pp. 64
Bob Abel, pp. 67Dr. El-Sayed was born in Alexandria, Egypt. After secondary school, he went to the University of Alexandria for his B.S. (1949) in Oceanography. After his M.S., he went to the Scripps Institute of Oceanography on a Fulbright Fellowship. He received his PhD from the University of Washington. As professor emeritus at Texas A & M, he directs a project with the Cooperative Marine Research Program in the Middle East. A friend asked him to work on a biological project on Drake Passage, Antarctica.
He worked for several years on vessels from Argentina and was later assigned to a ship for the study of krill. The science team included specialists interested in different aspects of the ecosystem. This was the first of many trips, including those on the Atlantic Ocean, Pacific Ocean, and Indian Ocean. He wrote the book “The Historical Perspective of the Antarctic Marine Research.” This book addresses the studies on the productivity of krill, in addition to phytoplankton and how solar radiation, nutrients, and the depletion of the ozone affected the marine ecosystem. The UVB radiation had a deleterious effect on the survival of the phytoplankton and nanoplankton.
Dr. El-Sayed describes his associations with SCAR, BIMASS, SCORE, and other research organizations. He summarizes the phasing out of CFCs production. Because some phytoplankton are inhibited by solar radiation, the maximum concentration of chlorophyll is between 10 and 20 meters. As a member of the Nimbus Experimental Team, Dr. El-Sayed used the coastal zone color scanner to study the krill ecosystem.
Major Topics
The University of Alexandria
The Scripps Institute of Oceanography
The University of Washington
Texas A & M University
Cooperative Marine Research Program in the Middle East
Drake Passage in Antarctica
Phytoplankton and nanoplankton on the Filchner Ice Shelf
Water currents in the Weddell Sea
Changes in the krill population
The formation of SCAR’s Marine Committee
The Antarctic marine ecosystem
Establishment of the first two International BIMASS experiments
The use of satellite images to study marine ecologyFunded by a grant from the National Science Foundation
Role of electron and hole trapping in the degradation and breakdown of SiO2 and HfO2 films
No full textWe investigated possible mechanisms for correlated defect production in amorphous (a) SiO2 and HfO2 films under applied stress bias using ab initio simulations. During bias application, electron injection into these films may lead to the localization of up to two electrons at intrinsic trapping sites which are present due to the natural structural disorder in amorphous structures. Trapping two electrons weakens Si-O and Hf-O bonds to such an extent that the thermally activated creation of Frenkel defects, O vacancies and O2- interstitial ions, becomes efficient even at room temperature. Bias application affects defect creation barriers and O2- interstitial diffusion. The density of trapping sites is different in a-SiO2 and a-HfO2. This leads to qualitatively different degradation kinetics, which results from different correlation in defect creation in the two materials. These effects affect TDDB statistics and its dependence on the film thickness
Significance of nannoplankton in primary production of the Ross Sea, Antarctica, during the 1972 Austral Summer
No full textDuring Eltanin Cruise 51 (January-February 1972), hydrographic features, phytoplankton standing crop, and primary production were determined between New Zealand and the Ross Ice Shelf. Four geographical regions with unique physical/chemical characteristics were delineated. They were the Subantarctic (SA), Antarctic Convergence (AC), Antarctic (AA), and Ross Ice Shelf (RIS) regions. Nannoplankton contribution to total phytoplankton standing crop (Chl a) and total primary production (C����� uptake) was measured by a fractionation process utilizing 10 (subscript "mean" symbol) mesh screens to separate the net and nannoplankton components. Mean phytoplankton standing crop values, integrated to 200 m, for the SA, AC, AA, and RIS regions were 23.62, 35.08, 51.41, and 96.37 mgChl a/m��, respectively. Nannoplankton accounted for 76.2%, 88.6%, and 64.9% of the standing crop in these respective areas. A significant correlation was found between the total phytoplankton standing crop in surface samples and standing crop estimates integrated over the water column. However, no correlation was found between size competition of the surface standing crop and that of the euphotic zone. Mean estimates of total phytoplankton production in the euphotic zone for the SA, AA, and RIS regions were 5.72, 6.18, and 9.97 mg/m��/hr. Nannoplankton production remained relatively constant in these regions, accounting for 90.2%, 67.0%, and 54.0% of total production in the respective regions. The increased phytoplankton standing crop and primary production observed in waters south of the Antarctic Convergence were accounted for by increases in the net plankton fraction. Average photosynthetic indexes (PI) were calculated for the total phytoplankton and the nannoplankton fraction. Significant estimates of 0.351 (P=.01) and 0.243 (P=.1) were obtained for the total PI and nannoplankton PI, respectively
Distributed chance-constrained model predictive control for condition-based maintenance planning for railway infrastructures
No full textWe develop a Model Predictive Control (MPC) approach for condition-based maintenance planning under uncertainty for railway infrastructure systems composed of multiple components. Piecewise-affine models with uncertain parameters are used to capture both the nonlinearity and uncertainties in the deterioration process. To keep a balance between robustness and optimality, we formulate the MPC optimization problem as a chance-constrained problem, which ensures that the constraints, e.g., bounds on the degradation level, are satisfied with a given probabilistic guarantee. Two distributed algorithms, one based on Dantzig-Wolfe decomposition and the other derived from a constraint-tightening technique, are proposed to improve the scalability of the MPC approach. Computational experiments show that the distributed method based on Dantzig-Wolfe decomposition performs the best in terms of computational time and convergence to global optimality. By comparing the chance-constrained MPC approaches with deterministic approach, and traditional time-based maintenance approach, we show that despite their high computational requirements, chance-constrained MPC approaches are cost-efficient and robust in the presence of uncertainties.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Team Bart De SchutterRailway EngineeringDelft Center for Systems and Contro
Distribution and abundance of pelagic copepods in the Drake Passage and off the coast of Argentina, with special reference to hydrology of these areas
No full textThe distribution of pelagic copepods with relation to the hydrology of the Drake Passage and off the coast of Argentina was studied in the plankton samples collected from four cruises made between February 1963 and July 1964. Hydrological studies made in the Drake Passage indicated that the position of the Antarctic Convergence does not show appreciable displacement from its mean position between 58° and 59°S lat in the Passage. Lower temperatures, higher dissolved oxygen content, and substantial increase in silicate values were noted as the Antarctic Convergence was crossed from north to south. During the October 1963 cruise the Sub-tropical Convergence was located at approximately 40°S lat off the Argentine continental shelf. Areas of upwelling were located between 40° and 43°S lat close to the border of the shelf. The distribution and composition of the pelagic copepods showed remarkable conformity with the hydrology of the areas under investigation. Based on the plankton samples studied, it was possible to divide the areas investigated into four regions: Antarctic, sub-Antarctic, transitional, and sub-tropical. The Antarctic region is characterized by the occurrence of Calanus propinquus, Calanoides acutus, Haloptilus ocellatus, Metridia gerlachei, Racovitzanus antarcticus, and Saphocalanus subbrevicornis. ..
The Pherobase
No full textThe Pherobase was developed by Dr. Ashraf El-Sayed, a research scientist at HortResearch in New Zealand, with the primary objective of providing "coverage of the literature published on chemical communication in insects." The Pherobase is intended for use by both scientific and non-scientific communities and currently contains "over 10000 entries, around 3000 molecules, and over 32000 static html pages that make it the world's largest database of behavior modifying chemicals." The site contains multiple Insect indices for such categories as Order, Family A-Z, and Species; References indices such as Discovery by Author, Discovery by Year, and References A-Z; and indices for Compounds, Compounds by Family, and Compounds by Genus. The site also contains a Contribution Form, and number of online forums relating to The Pherobase
Flexural behavior of seawater sea-sand concrete short beams reinforced with bamboo sheet
No full textBamboo reinforced concrete beams improved beam bearing capacity, but bamboo reinforcement's cross-sectional area affected its bond strength with concrete. Plain seawater seasand concrete beams are prone to cracking and poor flexural resistance. In order to solve these problems, this paper proposes bamboo sheet as a reinforcement material to improve the flexural behavior of plain seawater sea-sand concrete beams. Experimental results analyzed bamboo sheet reinforced seawater sea-sand concrete beam failure and ultimate bearing capacity. This test used 6 groups of 24 short beams: 5 groups of reinforced concrete and 1 group of contrast plain concrete, this test variable was reinforcement layers. The bamboo sheet reinforcement region was the entire beam bottom, which was strongly pasted to the beam bottom by resin glue. Bamboo sheet reinforcement increased beam deflection and flexural capacity, while the number of layers affected flexural behavior. When compared to plain seawater sea-sand concrete beam, the reinforcement effect was best when the number of bamboo sheet layers was 5, with the flexural capacity improvement degree being 81.88%. Finally, a theoretical calculation model for the bamboo sheet reinforced beam predicted its ultimate flexural capacity, with errors within 10%
Flexural performance of bamboo fiber-reinforced concrete mixed with seawater and sea sand
No full textIn the face of the huge consumption of fresh water and river sand by the concrete industry and the poor flexural performance of plain concrete, it is theoretically feasible and environmentally friendly to use bamboo fiber as a replacement to reinforce concrete mixed with seawater and sea sand. In this research, taking the volume fraction (0.6%, 1.2%, and 2.4%), aspect ratio (10, 20, and 30) and diameter (1.0, 1.5, and 2.0 mm) of bamboo fibers as parameters, 15 groups of bamboo fiber-reinforced concrete (BFRC) prisms and one control group of plain seawater sea sand concrete prisms were subjected to four-point bending test, followed by analyzing the crack pattern, ultimate load, mid-span deflection and strain. Under the condition of 1.2% volume fraction, 20 aspect ratio, 1.5 mm diameter, and 30 mm length, the maximum increase rate of flexural strength in this research was obtained, and then it was compared with that of flexural strength of concrete prisms reinforced by various natural fibers. In addition, relevant fitting equations and theoretical calculation formulas were derived, laying a foundation for the subsequent research and application of BFRC
Discursive design thinking: The role of explicit knowledge in creative architectural design reasoning
No full textThe main hypothesis investigated in this paper is based upon the suggestion that the discursive reasoning in architecture supported by an explicit knowledge of spatial configurations can enhance both design productivity and the intelligibility of design solutions The study consists of an examination of an architect's performance while solving intuitively a well-defined problem followed by an analysis of the spatial structure of their design solutions One group of architects will attempt to solve the design problem logically, rationalizing their design decisions by implementing their explicit knowledge of spatial configurations The other group will use an implicit form of such knowledge arising from their architectural education to reason about their design acts An integrated model of protocol analysis combining linkography and macroscopic coding is used to analyze the design processes The resulting design outcomes will be evaluated quantitatively in terms of their spatial configurations The analysis appears to show that an explicit knowledge of the rules of spatial configurations. as possessed by the first group of architects can partially enhance their function-driven Judgment producing permeable and well-structured spaces These findings are particularly significant as they imply that an explicit rather than an implicit knowledge of the fundamental rules that make a layout possible can lead to a considerable improvement in both the design process and product This suggests that by externalizing the design knowledge and restructuring it in a design model, creative thought can efficiently be evolved and stimulate
Remote sensing of ocean color in the northern Gulf of Mexico
No full textTypescript (photocopy).Remote sensing of ocean waters, using the Nimbus-7 Coastal Zone Color Scanner (CZCS), in the northern Gulf of Mexico during a 17 month period (November 1978 - March 1980) showed large variability in the spatial and temporal distributions of pigment fronts. Twenty-nine atmospherically- and geometrically-corrected CZCS orbits were processed into total pigment (chlorophyll a plus phaeopigments) images. A correction factor of 1.67 was applied to the pigment concentrations to correct for the tendency of the standard fluorometric method to underestimate chlorophyll a concentrations. Entrainment of coastal waters offshore was a dominant feature throughout the study. Intrusion of the Loop Current and its effect on surrounding waters was easily observed in the pigment imagery. The mean pigment concentration for the 17 month survey was 3.30 [plus or minus] 1.45 mg m^-3. Both the spring (March) and the fall (October) phytoplankton blooms were documented in the imagery, although precise dates for these maxima could not be determined due to the spacings between usuable CZCS orbits. A comparison was made between 7 thermal (CZCS channel 6) and pigment images. At times, the sea surface temperature expressions coincided with pigment gradients. In general, pigment imagery showed structural features not readily discernible in the thermal imagery. Development of a primary productivity algorithm was investigated using historical ground truth data on primary productivity, chlorophyll a concentration, sea surface temperature, and day length. Results indicated that, using these variables, a multiple regressions model could only describe 15% of the variability in production; therefore, a productivity algorithm was not applied to the remotely sensed pigment and thermal data. Conversion of the mean pigment concentration to production was calculated, with results ranging from 237 to 663 g C m^-2 yr^-1 depending on the regressions selected
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