Beam Based Alignment of Interaction Region Magnets

In conventional beam based alignment (BBA) procedures, the relative alignment of a quadrupole to a nearby beam position monitor is determined by finding a beam position in the quadrupole at which the closed orbit does not change when the quadrupole field is varied. The final focus magnets of the interaction regions (IR) of circular colliders often have some specialized properties that make it difficult to perform conventional beam based alignment procedures. At the HERA interaction points, for example, these properties are: (a) The quadrupoles are quite strong and long. Therefore a thin lens approximation is quite imprecise. (b) The effects of angular magnet offsets become significant. (c) The possibilities to steer the beam are limited as long as the alignment is not within specifications. (d) The beam orbit has design offsets and design angles with respect to the axis of the low-beta quadrupoles. (e) Often quadrupoles do not have a beam position monitor in their vicinity. Here we present a beam based alignment procedure that determines the relative offset of the closed orbit from a quadrupole center without requiring large orbit changes or monitors next to the quadrupole. Taking into account the alignment angle allows us to reduce the sensitivity to optical errors by one to two orders of magnitude. We also show how the BBA measurements of all IR quadrupoles can be used to determine the global position of the magnets. The sensitivity to errors of this method is evaluated and its applicability to HERA is shown

Determination of absorption length of CO2 and high power diode laser radiation for ordinary Portland cement

The laser beam absorption lengths of CO2 and a high power diode laser (HPDL) radiation for the ordinary Portland cement (OPC) surface of concrete have been determined. By employing Beer-Lambert’s law the absorption lengths for concrete of CO2 and a HPDL radiation were 470±22 μm and 177±15 μm respectively

In vivo monitoring of human intestinal ischaemia: An on-line rapid sampling microdialysis biosensor system

The primary aim of this thesis was to monitor in vivo intestinal ischemia using rapid sampling on-line microdialysis. A new variant of a clinical assay system was developed for use in gastrointestinal surgery. The assay could process on-line microdialysis samples for glucose and lactate concentrations at 30 seconds intervals in the concentration range of 25 μM to 30 mM. Intramural human bowel ischaemia was monitored intra-operatively in a clinical collaboration with Prof. Darzi and Prof. Hanna in St. Maryʼs Hospital, London using a microdialysis probe implantation technique devised by Mr. Samer Deeba. Dialysate levels stabilised within 10-15 minutes following implantation of the CMA 62 microdialysis probe. Clipping of arteries feeding the gastrointestinal tissue to be resected, did not lead to an immediate change in dialysate levels, but a fall in glucose and rise in lactate delayed by 17 ± 2 minutes, n=9. This suggests an additional pool of glucose availability in the bowel, and indicates a possible therapeutic window during bowel surgery. Parallel experimental work was carried out in swine model in the surgical labs of the healthcare company Tyco (Covidien) in Paris. Rapid sampling microdialysis was used to examine the effect of total ischaemia on an anastomosis site. The anastomotic site was devascularised by clamping the mesentery of both sides. Here the tissue reacted to ischaemia immediately, 5 minutes following clamping of feeding artery, compared with a healthy human bowel, suggesting that the additional glucose pool was unavailable in this situation. Physiological variable effects were studied to investigate further any difference with respect to the human in pig bowel physiology, which were not found. The no-net-flux method of in vivo recovery was used to determine the extracellular levels of glucose (0.47 ± 0.05 mM) in the intramural pig bowel. These were substantially lower than blood glucose values, representing a 10% of plasma levels and suggest a difference with human bowel. Finally, 7 patients were monitored after abdominal aortic aneurism repair surgery, for up to 2 days in the intensive care unit, to detect the possible on-set of ischaemia as a complication of inferior mesenteric artery occlusion. Basal microdialysis levels at 3.98 ± 0.75 mM for glucose and 1.38 ± 0.20 mM for lactate agreed well with those measured acutely during surgery, and were not sensitive to changes in plasma values. The lactate/glucose ratio between 1-2 days post-implantation was typically between 0.5-1.0 again similar to the ratio found intra-operatively. This validates the use of microdialysis intra-operatively and confirms the importance of this ratio. An in vivo calibration was performed in one patient with the variable flow rate method providing extracellular levels for glucose (5.8 ± 0.4 mM) and lactate (3.3 ± 0.2 mM) in intramural human bowel. These agree well with measured blood glucose values. Although major ischaemic failure was not seen in these patients, transient ischaemic events lasting 40 minutes and characterised by a lactate/glucose ratio increase to 2 were noticed. Finally, a quasi-periodic oscillatory pattern with inverse changes in glucose and lactate was observed during these patientsʼ monitoring. This was ascribed to gut peristalsis

Whipped oil stabilised by surfactant crystals

We describe a protocol for preparing very stable air-in-oil foams starting with a one-phase oil solution of a fatty acid (myristic acid) in high oleic sunflower oil at high temperature. Upon cooling below the solubility limit, a two-phase mixture consisting of fatty acid crystals (length around 50 μm) dispersed in an oil solution at its solubility is formed which, after whipping, coat air bubbles in the foam. Foams which do not drain, coalesce or coarsen may be produced either by increasing the fatty acid concentration at fixed temperature or aerating the mixtures at different temperatures at constant concentration. We prove that molecular fatty acid is not surface-active as no foam is possible in the one-phase region. Once the two-phase region is reached, fatty acid crystals are shown to be surface-active enabling foam formation, and excess crystals serve to gel the continuous oil phase enhancing foam stability. A combination of rheology, X-ray diffraction and pulsed nuclear magnetic resonance is used to characterise the crystals and oil gels formed before aeration. The crystal-stabilised foams are temperature-sensitive, being rendered completely unstable on heating around the melting temperature of the crystals. The findings are extended to a range of vegetable oil foams stabilised by a combination of adsorbed crystals and gelling of the oil phase, which destabilise at different temperatures depending on the composition and type of fatty acid chains in the triglyceride molecules

Tabulated Data From a Pressure-Distribution Investigation at Mach Number 2.01 of a 45 Deg Sweptback-Wing Airplane Model at Combined Angles of Attack and Sideslip

A pressure-distribution investigation of a wing-body combination has been conducted in the Langley 4- by 4-foot supersonic pressure tunnel at a Mach number of 2.01. The model configuration consisted of an ogive-circular-cylinder body (fineness ratio of approximately ii) and a wing with 45 deg of sweepback at the quarter-chord line, an aspect ratio of 4, and a taper ratio of 0.2. Data were obtained on high-, mid-, and low-wing configurations and for the body and wing alone for a range of angles of attack and yaw from 0 deg to 15 deg. The tabulated pressure coefficients are presented in this report

Deep reef fish surveys by submersible on Alderdice, McGrail, and Sonnier Banks in the Northwestern Gulf of Mexico

Submersible surveys at numerous reefs and banks in the northwestern Gulf of Mexico (NWGOM) were conducted as part of the Sustainable Seas Expedition (SSE) during July/August 2002 to identify reef fish communities, characterize benthic habitats, and identify deep coral reef ecosystems. To identify the spatial extent of hard bottom reef communities, the Flower Garden Banks National Marine Sanctuary (FGBNMS) and the U.S. Geological Survey (USGS) mapped approximately 2000 km2 of the Northwestern Gulf of Mexico (NWGOM) continental shelf during June 2002 with high-resolution multibeam bathymetry. Previous investigations conducted on the features of interest (with the exceptions of East and West Flower Garden and Sonnier Banks, accessible by SCUBA) had not been conducted since the 1970s and 1980s, and did not have the use of high-resolution maps to target survey sites. The base maps were instrumental in navigating submersibles to specific features at each study site during the Sustainable Seas Expedition (SSE)—a submersible effort culminating from a partnership between the National Atmospheric and Oceanic Administration (NOAA) and the National Geographic Society (NGS). We report the initial findings of our submersible surveys, including habitat and reef fish diversity at McGrail, Alderdice, and Sonnier Banks. A total of 120 species and 40,724 individuals were identified from video surveys at the three banks. Planktivorous fishes constituted over 87% by number for the three banks, ranging from 81.4% at Sonnier Banks to 94.3% at Alderdice Bank, indicating a direct link to pelagic prey communities, particularly in the deep reef zones. High numbers of groupers, snappers, jacks, and other fishery species were observed on all three features. These sites were nominated as Habitat Areas of Particular Concern (HAPC) by the Gulf of Mexico Fishery Council in March 2004. Data obtained during this project will contribute to benthic habitat characterization and assessment of the associated fish communities through future SCUBA, ROV, and submersible missions, and allow comparisons to other deep reef ecosystems found throughout the Gulf of Mexico and western Atlantic Ocean