An empirical study on the effects of translucency on photometric stereo

We present an empirical study on the effects of translucency on photometric stereo. Our study shows that the impact on the accuracy of the photometric normals is related to the relative size of the geometrical features and the mean free path. We show that under simplified conditions, the obtained photometric normals are a blurred version of the true surface normals, where the blur kernel is directly related to the subsurface scattering profile. We furthermore investigate the impact of scattering albedo, index of refraction, and single scattering on the accuracy. We perform our analysis using simulations, and demonstrate the validity on a real world example.     

Pressure distribution on the anatomic landmarks of the knee and the effect of kneepads

This study examines stress transmitted to anatomic landmarks of the knee (patella, combined patella tendon and tibial tubercle) while in static kneeling postures without kneepads and while wearing two kneepads commonly worn in the mining industry. Ten subjects (7 male, 3 female) simulated postures utilized in low-seam mines: kneeling in full flexion; kneeling at 90° of knee flexion; and kneeling on one knee while in one of three kneepad states (no kneepads, non-articulated kneepads, and articulated kneepads). For each posture, peak and mean pressure on the anatomic landmarks of the knee were obtained. The majority of the pressure was found to be transmitted to the knee via the combined patellar tendon and tibial tubercle rather than through the patella. While the kneepads tested decreased the maximum pressure experienced at the combined patellar tendon and tibial tubercle, peak pressures of greater than 25 psi were still experienced over structures commonly injured in mining (e.g. bursa sac - bursitis/Miner’s Knee). The major conclusion of this study is that novel kneepad designs that redistribute the stresses at the knee across a greater surface area and to other regions of the leg away from key structures of the knee are needed.     

Problem reduction heuristic for the 0-1 multidimensional knapsack problem

This paper introduces new problem-size reduction heuristics for the multidimensional knapsack problem. These heuristics are based on solving a relaxed version of the problem, using the dual variables to formulate a Lagrangian relaxation of the original problem, and then solving an estimated core problem to achieve a heuristic solution to the original problem. We demonstrate the performance of these heuristics as compared to legacy heuristics and two other problem reduction heuristics for the multi-dimensional knapsack problem. We discuss problems with existing test problems and discuss the use of an improved test problem generation approach. We use a competitive test to highlight the performance of our heuristics versus the legacy heuristic approaches. We also introduce the concept of computational versus competitive problem test data sets as a means to focus the empirical analysis of heuristic performance.     

Comments on `Stabilisability and detectability of discrete-timetime-varying systems' by J.C. Engwerder

An alleged counterexample in the above-titled paper (ibid., vol.35, no.4, pp.425-429, Apr. 1990) to a main result of B.D.O. Anderson and J.B. Moore (SIAM J. Contr. Optimiz., vol.19, no.1, pp.22-32, 1981) is shown not to be a counterexample in actuality     

Characterization of a complex mixture of aromatic and heterocyclic acids obtained from oxidation of lignite coal and its solvent-refined products

This study reports the results from the oxidation, using sodium dichromate, of a solvent-refined lignite (SRL) and its feed coal and the effects of varying the ratio of oxidant to coal. The numerous aromatic and heteroaromatic carboxylic acids isolated were identified as their methyl esters by g.c./m.s. and h.r.m.s. Oxidation of SRL with a limited amount of dichromate yielded a large number of polycyclic aromatic and heteroaromatic acids not found in the oxidation of the lignite. These results indicate that the SRL process produces highly-condensed aromatic molecules.     

A fluidized bed retort for oil sands

Fluid bed retorting of oil sands is a viable method of extracting oil from mined oil sands. The process is based on a direct heating concept in which one vessel is utilized for the pyrolysis and vaporization of the bitumen contained in the oil sand and for the burning of the residuals which remain with the sand. Experimental results show that a significantly upgraded liquid hydrocarbon product can be obtained. Oil yields can exceed eighty per cent of the bitumen present in the feed material. The sulfur content of the produced oil is reduced. Gas produced can have a significant heating value and contains sulfur mainly in the form of hydrogen sulfide. Refluxing of the overhead product increases liquid yields and reduces the sulfur content of the oil. Water injection and the use of enriched air has a beneficial effect on the process. Thermal efficiencies in excess of eighty per cent can be achieved without recovering the heat from the expended sand.     

Postinjury neutrophil priming and activation: an early vulnerable window

BACKGROUND: Generation of extracellular, cytotoxic superoxide anion (O2-) by polymorphonuclear neutrophils (PMNs) contributes to an unbridled inflammatory response that can precipitate multiple organ failure (MOF). Release of O2- is markedly enhanced when activated PMNs have been previously "primed" by inflammatory mediators, such as those expressed after trauma. We therefore hypothesized that PMN priming occurs as an integral part of the early inflammatory response to trauma. METHODS: PMNs were obtained from 17 high-risk patients with torso trauma at 3, 6, 12, 24, 48, and 72 hours after injury, as well as from 10 healthy donors, and the in vitro release of O2- was quantitated with a kinetic, superoxide dismutase (SOD)-inhibitable cytochrome c reduction assay. PMN O2- release was measured in the presence and absence of 1 mumol/L N-formyl-methionyl-leucyl-phenylalanine (fMLP) and after priming and activation with 20 nmol/L platelet-activating factor (PAF) and 1 mumol/L fMLP, respectively. RESULTS: In vitro PMN O2- release was used to determine whether postinjury PMNs were (1) activated in vivo, (2) primed in vivo, or (3) primable in vitro. Unstimulated PMNs from trauma patients spontaneously expressed modest amounts of O2- in vitro from 6 to 48 hours after injury, suggesting endogenous activation. Also, fMLP-activated PMNs collected between 3 and 24 hours after injury expressed more O2- than controls (p < or = 0.02), indicating in vivo, trauma-related priming. Furthermore, postinjury PMNs were maximally primed in vivo (i.e., in vitro exposure to PAF before fMLP activation failed to significantly enhance O2- release) as compared to PMNs treated with fMLP. CONCLUSIONS: These data indicate that major torso trauma (first hit) primes and activates PMNs within 3 to 6 hours after injury. Consequently, we postulate that postinjury priming of PMNs may create an early vulnerable window during which a second hit (e.g., a secondary operation or delayed hemorrhage) activates exuberant PMN O2- release, rendering the injured patient at high risk for MOF.     

Production, characterization and application of monoclonal antibodies against the organophosphorus nerve agent Vx

Two monoclonal antibodies (Vx-BB8 and Vx-EA11) to the chemical warfare agent Vx were produced and characterized. A competitive inhibition enzyme immunoassay was developed to detect Vx concentrations as low as 3.7 x 10(-7) - 3.7 x 10(-6) mol/l in biological samples. Vx-BB8 400 micrograms given intravenously immediately before 1 x LD95 Vx or 400 micrograms Vx-BB8 intraperitoneally 1.5 h-3 days before 1 x LD95 Vx could protect all the tested mice from death.