Projective Visual Hulls

This article presents a novel method for computing the visual hull of a solid bounded by a smooth surface and observed by a finite set of cameras. The visual hull is the intersection of the visual cones formed by back-projecting the silhouettes found in the corresponding images. We characterize its surface as a generalized polyhedron whose faces are visual cone patches; edges are intersection curves between two viewing cones; and vertices are frontier points where the intersection of two cones is singular, or intersection points where triples of cones meet. We use the mathematical framework of oriented projective differential geometry to develop an image-based algorithm for computing the visual hull. This algorithm works in a weakly calibrated setting–-that is, it only requires projective camera matrices or, equivalently, fundamental matrices for each pair of cameras. The promise of the proposed algorithm is demonstrated with experiments on several challenging data sets and a comparison to another state-of-the-art method.     

New Organic Electrode Materials for Ultrafast Electrochemical Energy Storage

Organic materials are both environmentally and economically attractive as potential electrode candidates. This Research News reports on a new class of stable and electrically conductive organic electrodes based on metal porphyrins with functional groups that are capable of electrochemical polymerization, rendering the materials promising for electrochemical applications. Their structural flexibility and the unique highly conjugated macrocyclic structure allows the produced organic electrodes to act as both cathode and anode materials giving access to fast charging as well as high cycling stability. The extreme thermal and chemical stability of the porphyrin‐based organic electrodes and their chemical versatility suggest an important role for these molecular systems in the further development of novel electrochemical energy storage applications.     

Melt spinning and characterization of hollow fibers from poly(4-methyl-1-pentene)

In this article, the melt spinning behavior of poly(4-methyl-1-pentene) (PMP) hollow fibers (HF) is examined. The melt spinning trials are carried out on a pilot scale melt spinning plant with different settings while a 10-hole 2c-shaped spinneret is used. It is found that the winding speed mainly affects the outer fiber diameter. The influence of different melt spinning parameters is investigated, in particular temperatures, take-up velocities, and the use of quench air. For this purpose, the shape and crystalline structure of the fibers are analyzed using a light microscope, a scanning electron microscope, and wide-angle X-ray scattering. The shape of the fibers is mainly influenced by the temperature settings in the melt spinning process. As a reasonable lower limit, a melt spinning temperature of 280°C is identified. Concerning the crystallinity, a saturation going along with a slight reduction of the polymer chain orientation is observed at elevated take-up velocities.     

Development of antifouling ultrafiltration PES membranes for concentration of hemicellulose

A new approach for one-stage facile membrane modification during non-solvent induced phase separation (NIPS)-process is proposed. The novelty of this study is that cheap and commercially available anionic high molecular polyacrylamide-based flocculant (AHMPF) is applied for the first time as an additive to coagulation bath (CB). The series of polyethersulfone membranes were prepared using 0.05–0.3 wt% AHMPF aqueous solution as CB at different temperatures (25–50°C) via NIPS. The effect of AHMPF concentration on the structure, composition and hydrophilicity of membranes was investigated. The separation and antifouling performance were evaluated during filtration of bovine serum albumin (BSA) solution and thermomechanical pulp mills process water (ThMP) in order to concentrate hemicellulose. The successful immobilization of AHMPF into the structure of membranes selective layer (not bottom layer) was confirmed by FTIR spectroscopy. It was established that despite the similar rejection of hemicellulose (88.8–93%) and lignin (20–21.4), modified membranes demonstrate 3–8 times higher flux and 2 times higher FRR (43.8% for reference membrane and 86.5% for modified one) in ThMP ultrafiltration. The developed membrane was found to be highly efficient in hemicellulose concentration and purification in pulp industry.     

Synthetic pores with reactive signal amplifiers as artificial tongues

The sensation of taste is mediated by activation or deactivation of transmembrane pores. Artificial stimulus-responsive pores are enormously appealing as sensor components because changes in their activity are readily detectable in many different ways. However, the detection of multiple components in complex matrices (such as foods) with one pore sensor has so far remained elusive because the specificity necessary for sensing a target compound in complex mixtures is incompatible with the broad applicability needed for the detection of multiple components. Here, we present synthetic pores that, like our tongues, can sense flavours in food and in addition make them visibly detectable. Differential sensing and pattern recognition are solutions based on empirical and biomimetic approaches. They have been explored with synthetic receptor arrays and electronic tongues. In contrast, our approach is non-empirical as it exploits reactive amplifiers that covalently capture elusive analytes after enzymatic signal generation and drag them into synthetic pores for blockage. Reactive amplification proved to be highly sensitive and adaptable to various analytes and pores. Moreover, it can be combined with reactive filtration for minimizing interference. The system was tested on real food samples for detection of sucrose, lactose, lactate, acetate, citrate and glutamate to demonstrate the feasibility of these synthetic pores as universal sensors.     

Dichromated pullulan diffraction gratings: influence of environmental conditions and storage time on their properties

Investigations of the environmental stability of diffraction gratings, recorded in dichromated pullulan (DCP), are reported. Profile changes of DCP surface relief gratings, under high humidity conditions, were analyzed using an atomic force microscope. It was found that the profile was not altered, while the diffraction efficiency was preserved. The influence of storage life on the diffraction efficiency and surface profile of DCP gratings were also investigated. It was concluded that DCP gratings offer much better stability compared with the dichromated gelatin.     

Laser-induced fluorescence-capillary electrophoresis and fluorescence microplate reader measurement: two methods to quantify the effect of antibiotics

Putative antibiotic drugs have to be classified according to their bactericidal potential. Two new methods by means of fluorescence spectroscopy (FS) using a fluorescence microplate reader (FMR) and laser-induced fluorescence capillary electrophoresis (LIF-CE), respectively, were developed for the assessment of the bactericidal efficiency using the LIVE/DEAD BacLight viability kit composed of the two fluorescent nucleic acid stains, SYTO9 (stains all cells green) and propidium iodide (stains cells with damaged membrane red). By correlation of the ratio of green and red fluorescence with the percentage of live cells by employing FS and LIF-CE, respectively, dose response curves of drug-treated Pseudomonas spp. and Streptococcus spp. samples were calculated, which allowed for the assessment of ED50 values. Both methods led to similar results which were in agreement with the minimum inhibitory concentrations (MICs) obtained by conventional broth microdilution. The application of the BacLight viability kit on drug-treated bacteria cultures presents a rapid method of assessing the antibiotic potency which is of great importance for high throughput screening in the development of new antibiotics. Additionally, the new LIF-CE method, which based on the use of a second unlabeled bacteria injection as a stacking front, allowed drawing conclusions from the electrophoretic profile about the constitution of the bacterial population. Thus, the tendency of bacterial chain formation and alterations in the live/dead ratio of the bacterial composition can be directly observed in the presence of different antibiotics.     

Validation of a vector version of the 6S radiative transfer code for atmospheric correction of satellite data. Part II. Homogeneous Lambertian and anisotropic surfaces

This is the second part of the validation effort of the recently developed vector version of the 6S (Second Simulation of a Satellite Signal in the Solar Spectrum) radiative transfer code (6SV1), primarily used for the calculation of look-up tables in the Moderate Resolution Imaging Spectroradiometer (MODIS) atmospheric correction algorithm. The 6SV1 code was tested against a Monte Carlo code and Coulson's tabulated values for molecular and aerosol atmospheres bounded by different Lambertian and anisotropic surfaces. The code was also tested in scalar mode against the scalar code SHARM to resolve the previous 6S accuracy issues in the case of an anisotropic surface. All test cases were characterized by good agreement between the 6SV1 and the other codes: The overall relative error did not exceed 0.8%. The study also showed that ignoring the effects of radiation polarization in the atmosphere led to large errors in the simulated top-of-atmosphere reflectances: The maximum observed error was approximately 7.2% for both Lambertian and anisotropic surfaces.     

The importance of ‘process’ in Rethinking Project Management: The story of a UK Government-funded research network

This paper tells the story of a UK Government-funded research network called Rethinking Project Management, funded by the Engineering and Physical Sciences Research Council between 2004 and 2006. The story is significant because of the considerable attention given to the process of the Network, both the inquiry process of ‘rethinking’ project management, and the broader social process in which the rethinking activity was carried out. In telling this story, the lead organisers explain how the inquiry process was organised as a learning system to enable the Network to ‘learn’ its way to relevant directions for future research, and secondly, how the broader social process was organised and facilitated to create a context for effective interaction between the people involved. A significant challenge in managing the research programme was how to engage the participants in purposeful inquiry, which would serve not only the primary aims of the Network, but would also yield new and interesting insights for the people involved. This paper seeks to explain how the lead organisers addressed this challenge, through a detailed and reflective discussion of how the research programme was organised and facilitated to achieve the Network’s primary aims. In summary, the principal aim in telling this story is to highlight the importance of process in collaborative research activity involving academics and practitioners, in order that other researchers might draw on the experience of this Network.