Optical diagnostics of mercury jet for an intense proton target

An optical diagnostic system is designed and constructed for imaging a free mercury jet interacting with a high intensity proton beam in a pulsed high-field solenoid magnet. The optical imaging system employs a backilluminated, laser shadow photography technique. Object illumination and image capture are transmitted through radiation-hard multimode optical fibers and flexible coherent imaging fibers. A retroreflected illumination design allows the entire passive imaging system to fit inside the bore of the solenoid magnet. A sequence of synchronized short laser light pulses are used to freeze the transient events, and the images are recorded by several high speed charge coupled devices. Quantitative and qualitative data analysis using image processing based on probability approach is described. The characteristics of free mercury jet as a high power target for beam-jet interaction at various levels of the magnetic induction field is reported in this paper.     

In vitro displacement by rat serum of adsorbed radiolabeled poloxamer and poloxamine copolymers from model and biodegradable nanospheres

Poloxamer 407 and poloxamine 908 have been used by many research groups to modify the surface of both model latex and biodegradable nanospheres, thereby producing nanospheres that have shown reduced protein adsorption in vitro and extended circulation times in vivo. A potential limitation of such systems is the desorption of the copolymer coating layer. We describe a two-stage process to radiolabel poloxamer 407 and poloxamine 908 that has facilitated an investigation into this potential desorption, in vitro. The first stage of the labeling procedure involved the substitution of the terminal hydroxyl groups in each poly(ethylene oxide) (PEO) chain of poloxamer 407 and poloxamine 908 with an amino group. The aminated copolymers were then radiolabeled with 125Iodine Bolton-Hunter reagent. The efficiency of labeling was calculated to be approximately 20% for the tetramine poloxamine 908 and approximately 33% for the diamine poloxamer 407. Remaining free amino groups were then either acetylated, using acetic anhydride, or left in the free amino form. Covalent linkage of the radiolabel to the copolymer was confirmed by nuclear magnetic resonance (NMR) and infrared (IR) spectroscopy. The stability of the link between radiolabel and copolymer to hydrolysis was also confirmed; <4% loss of radiolabel occurred from poloxamine 908 after incubation in phosphate-buffered saline (PBS) at 37 degrees C for 8 days. The radiolabeled copolymers (with the free amino groups acetylated) were then used in experiments that have given the first direct evidence that adsorbed copolymers can be displaced by serum proteins in significant amounts from the surface of model and biodegradable nanospheres. The displacement was highly dependent on copolymer-nanosphere compatibility, with up to 78% of 125I tetramine poloxamine 908 being displaced from poly(lactide-co-glycolide) (PLGA) nanospheres in 24 h, compared with 20% displacement of 125I tetramine poloxamine 908 in 24 h from polystyrene nanospheres. These results have direct implication for the future design of drug delivery systems based on coated nanospheres.     

Mitigation of Damages to Electric Utilities Due to High Winds

Extreme winds, hurricanes, and tornadoes produce significant damage to electrical transmission and distribution line structures. The damage produces loss of power to the affected communities for a variable length of time, depending on severity of damage. Most institutions whose operations would be life threatening in the event of power failure have emergency power. However, loss of power to both residences and businesses can have economic impact on the community in the form of temporary housing shortages and loss of business. Utility companies seem to cope with wind damage fairly well, following risk management procedures in designing for wind and in providing alternate routing for distribution lines. However, continuing research and developments are needed to keep abreast of the problem.     

Mapping intertidal estuarine sediment grain size distributions through airborne remote sensing

The intertidal environments of estuaries represent critical exchange environments of sediment and sediment bound contaminants. Ecological and sedimentological related investigations of these environments require monitoring methods that provide rapid spatially representative data on sediment grain size distribution. Remote sensing has the potential to provide synoptic information of intertidal environments. Previous in situ and laboratory-based reflectance investigations have demonstrated that for effective quantification of sediment grain size distributions, remote sensing platforms must include measurements within the short-wave infrared (SWIR). In addition, the timing of image acquisition, in relation to tidal cycles and sediment moisture content, is critical in optimising the spectral differences between the coarser sand and finer ‘mud’ fraction of sediments. Daedalus 1268 Airborne Thematic Mapper (ATM) has been identified as an appropriate platform and sensor for providing accurate synoptic maps of estuarine sediment distributions. This paper presents the results from the application of ATM 1.75 m resolution data to the mapping of surface sediment grain-size distributions across intertidal areas of Ribble Estuary, Lancashire, UK. ATM imagery was acquired after the intertidal area was exposed to strong summer drying conditions. Pre-processing and linear unmixing of the imagery collected of the intertidal zone following a period of drying allowed accurate sub-pixel determinations (1.75 m resolution) of sediment clay (r²=0.79) but less accurate for sand (r²=0.60). The results also demonstrate deterioration in the image calibration with increasing sediment moisture content and microphytobenthos cover. However, recombining the subpixel end member abundances through multivariate regression analysis improved the image calibration significantly for both sediment clay and sand content (r²>0.8) for imagery collected in both dryer and wetter conditions. These results demonstrate that ATM data, or similar, can be used to gain quantitative information on intertidal sediment distributions and such data has application to a wide variety of estuarine research.     

An automated technique for real-time production of lifelike animations of American Sign Language

Generating sentences from a library of signs implemented through a sparse set of key frames derived from the segmental structure of a phonetic model of ASL has the advantage of flexibility and efficiency, but lacks the lifelike detail of motion capture. These difficulties are compounded when faced with real-time generation and display. This paper describes a technique for automatically adding realism without the expense of manually animating the requisite detail. The new technique layers transparently over and modifies the primary motions dictated by the segmental model and does so with very little computational cost, enabling real-time production and display. The paper also discusses avatar optimizations that can lower the rendering overhead in real-time displays.     

Short answers to deep questions: supporting teachers in large‐class settings

In large class settings, individualized student–teacher interaction is difficult. However, teaching interactions (e.g., formative feedback) are central to encouraging deep approaches to learning. While there has been progress in automatic short‐answer grading, analysing student responses to support formative feedback at scale is arguably some way from being widely applied in practice. However, analysing student written responses can provide insights into student conceptions, thus directly informing teacher actions. Indeed, we argue that analysing student responses to provide feedback directly to teachers is as worthy a goal as providing individualized feedback to students and is achievable given the current state‐of‐the‐art in natural language processing. In this paper, we analyse student written responses to short‐answer questions posed in the context of a large first year health sciences course. Each question was designed to elicit deep responses. Our qualitative analysis illustrates the variability in student responses and reveals multiple relationships between these responses, course materials and the questions posed. Such information can be invaluable for teacher praxis. We conclude with a conceptual ‘dashboard’ that categorizes student responses and reveals relationships between responses, course resources and the questions. Such a dashboard could provide timely, actionable insights for teachers and help foster deep learning approaches for students.     

When Deceitful Chats Look Truthful

The amount of deception taking place via electronic text-based communication is increasing. Research has sought to automatically detect deception by analyzing the text from the communicator. However, the deceptive intent of the communication partner is being ignored. We compare the text from subjects who are trying to deceive each other, subjects trying to deceive truth tellers, subjects telling the truth to truth tellers, and subjects telling the truth to deceivers. We hypothesize that despite the intent of the partner, deceitful text will cluster closest to deceitful text. We cluster each of the four conditions using the text content. The cluster algorithm placed subjects trying to deceive each other closest to subjects telling the truth to each other. In this analysis, the language that led subjects to choose the same outcomes had a stronger effect than the language tied to being deceitful or truthful.     

Integrating operational and risk information with system risk models in air traffic control

Cognition, Technology & Work - The next generation Air Transport Management (ATM) requires performance-based safety management that is fully integrated into seamless operational management. To...