Structural drivers controlling sulfur solubility in alkali aluminoborosilicate glasses

If the direct feed approach to vitrify the Hanford's tank waste is implemented, the low activity waste (LAW) will comprise higher concentrations of alkali/alkaline-earth sulfates than expected under the previously proposed vitrification scheme. To ensure a minimal impact of higher sulfate concentrations on the downstream operations and overall cost of vitrification, advanced glass formulations with enhanced sulfate loadings (solubility) are needed. While, the current sulfate solubility predictive models have been successful in designing LAW glasses with sulfate loadings <2 wt.%, it will be difficult for them to design glass compositions with enhanced loadings due to our limited understanding of the fundamental science governing these processes. In this pursuit, this article unearths the underlying compositional and structural drivers controlling the sulfate solubility in model LAW glasses. It has been shown that the preferentially removes non-framework cations from the modifier sites in the silicate network, thus, leading to the polymerization in the glass network via the formation of ring-structured borosilicate units. Furthermore, though the sulfate solubility slightly decreases with increasing Li⁺/Na⁺ in the glasses, the prefers to be charge compensated by Na⁺, as it is easier for to break Na–O bonds instead of Li–O bonds.     

Spatial distribution of biomass consumption as energy in rural areas of the Indo-Gangetic plain

Biomass is widely used as energy source in rural households in India. Biomass samples and socio-economic data have been collected at district level in the rural areas of Indo-Gangetic plain (IGP), India to determine the emissions of trace gases and aerosols from domestic fuels. Dung cake, fuelwood and crop residue are main sources of energy in rural areas of the IGP. Dung cake is the major domestic fuel (80-90%) in the rural areas of Delhi, Punjab, Haryana, Uttar Pradesh, Bihar and West Bengal, whereas, 99% of rural households in Uttarakhand use wood as the main energy source. Using crop production data and usage of crop residues as energy, new consumption values have been estimated (21.13 Mt). Present information on the domestic fuel usage would be helpful in determining budgets estimates of trace gases and aerosols for India.     

Antifungal activity and chemical composition of Citrus reticulata Blanco essential oil against phytopathogens from North East India

The essential oil (EO) isolated by hydro-distillation from the peel of fully matured ripen fruits of Citrus reticulata Blanco were analyzed by GC and GC-MS. Thirty seven different components were identified constituting approximately ≥99% of the oil. The major components were limonene (46.7%), geranial (19.0%), neral (14.5%), geranyl acetate (3.9%), geraniol (3.5%), β-caryophyllene (2.6%), nerol (2.3%), neryl acetate (1.1%) etc. The antifungal activity of the oil was tested by poisoned food (PF) technique and the volatile activity (VA) assay against five plant pathogenic fungi viz Alternaria alternata (Aa), Rhizoctonia solani (Rs), Curvularia lunata (Cl), Fusarium oxysporum (Fo) and Helminthosporium oryzae (Ho). The oil showed better activity in VA assay. The Minimum inhibitory concentration (MIC) for Aa, Rs and Cl was 0.2 ml/100 ml whereas >0.2 ml/100 ml for Fo and Ho in PF technique. Fungal sporulation was also completely inhibited at 2 ml/100 ml of the oil except for Cl and Ho, which was only 0.5% (±0.5) and 0.25% (±0.25) respectively as compared to control.     

An integrated path-planning and control approach for nonholonomic unicycles using switched local potentials

In this paper, navigation and control of an autonomous mobile unicycle robot in an obstacle-ridden environment is considered. The unicycle dynamic model used has two differentially driven wheels, with the motor torques as the system input. Two novel potential-field-based controllers are derived, which stabilize the robot within a surrounding circular area (henceforth called a bubble) of arbitrary size. The first controller takes the unicycle to the center of its bubble, while the second corrects its orientation. The designed potentials also work with a kinematic model. Explicit bounds for permissible initial speeds are derived, such that maximum torque limits and/or maximum speed limits are not violated once the controller is activated. These controllers are then embedded in a navigation framework. An existing global planner is used to first create a string of variable-sized bubbles which connect the start point to the goal point, with each bubble's size indicative of the radial obstacle clearance available from its center. The robot then keeps itself within a fixed-sized bubble, which it then moves in discrete steps, according to the direction provided by the global plan, while repulsively avoiding unexpected obstacles. Hence, the gross movement is created by switching local potential-field-based controllers. This scheme is first verified in computer simulation of a single robot moving in a maze. It is then implemented on an experimental setup of robots equipped with proximity sensors. Results are presented to illustrate the effectiveness of the system.     

Adaptive Web Search: Evolving a Program That Finds Information

Anyone who's used a computer to find information on the Web knows that the experience can be frustrating. Search engines are incorporating new techniques (such as examining document link structures) to increase effectiveness. However, searchers all too often face one of two outcomes: reviewing many more Web pages than they'd prefer or failing to find as much useful information as they really want. We introduce a new retrieval technique that exploits users' persistent information needs. These users might include business analysts specializing in genetic technologies, stockbrokers keeping abreast of wireless communications, and legislators needing to understand computer privacy and security developments. To help such searchers, we evolve effective search programs by using feedback based on users' judgments about the relevance of the documents they've retrieved. This approach uses genetic programming to automatically evolve new retrieval algorithms based on a user's evaluation of previously viewed documents     

Edge-guided boundary delineation in prostate ultrasound images

Accurate detection of prostate boundaries is required in many diagnostic and treatment procedures for prostate disease. In this paper, a new paradigm for guided edge delineation is described, which involves presenting automatically detected prostate edges as a visual guide to the observer, followed by manual editing. This approach enables robust delineation of the prostate boundaries, making it suitable for routine clinical use. The edge-detection algorithm is comprised of three stages. An algorithm called sticks is used to enhance contrast and at the same time reduce speckle in the transrectal ultrasound prostate image. The resulting image is further smoothed using an anisotropic diffusion filter. In the third stage, some basic prior knowledge of the prostate, such as shape and echo pattern, is used to detect the most probable edges describing the prostate. Finally, patient-specific anatomic information is integrated during manual linking of the detected edges. The algorithm was tested on 125 images from 16 patients. The performance of the algorithm was statistically evaluated by employing five expert observers. Based on this study, we found that consistency in prostate delineation increases when automatically detected edges are used as visual guide during outlining, while the accuracy of the detected edges was found to be at least as good as those of the human observers. The use of edge guidance for boundary delineation can also be extended to other applications in medical imaging where poor contrast in the images and the complexity in the anatomy limit the clinical usability of fully automatic edge-detection techniques.     

Distinctive karyotypes and growth patterns in nude mice reveal cross-contamination in an established human cancer cell line

A human cancer cell line was found to be heterogeneous for expression of the epidermal growth factor receptor (EGFR). Clones and variants of this cell line were separated on the basis of EGFR expression level, and those expressing high EGFR had different growth characteristics, in vitro and in vivo, than variants expressing low levels of EGFR. Karyotype analysis revealed that the heterogeneity was the result of mixing of two lines, the 2774 ovarian cancer cell line, and the SW620 colon cancer cell line. Our results reinforce the necessity for accurate identification of cell lines. Also, that measurement of gene expression on a single cell level, for example by flow cytometric analysis, can be more informative than measurements of cell lysates, since the initial indication of heterogeneity would not have been detected by northern or western blotting. The different cell types retained characteristic growth patterns when injected i.p. in nude mice, i.e. peritoneal carcinomatosis and ascites formation by the 2774 ovarian cancer cells, and liver metastasis and growth of discrete abdominal tumors by the SW620 colon cancer.     

Comments on "A uniform geometrical theory of diffraction for an edge in a perfectly conducting surface"

The edge diffraction coefficients of Kouyoumjian and Pathak, when applied to edges in curved screens produce discontinuities in the diffracted fields which do not coincide with those of the specular field on the concave side of the screen. In regions where coincidence occurs the discontinuities add, rather than cancel. The field calculated from the diffraction coefficient violates the principle of reciprocity.     

Effect of pressure and substrate temperature on the deposition of nano-structured silicon-carbon-nitride superhard coatings by magnetron sputtering

A systematic investigation on the deposition of silicon-carbon-nitride (Si-C-N) films under varying deposition conditions such as pressure, substrate temperature and nitrogen content was carried out by radio frequency and direct current magnetron sputtering techniques. Significant role of the different deposition parameters on hardness and structure in the film was observed. It was observed that there was a certain range of nitrogen to argon partial pressure ratio (90:10 to 98:2) for which the particle size was reduced and the films were smooth with fine particle growth, beyond this limit the films had larger particle growth and roughness. The hardness of the deposited film varied between 4400 Hv and 473 Hv depending on deposition condition. Si-C-N film with hardness above 4400 Hv by reactive RF magnetron sputtering from SiC-C composite target in nitrogen-argon was obtained. X-ray diffraction studies revealed the amorphous nature of the deposited films, whereas nano-crystallinity of the particles was noticed during atomic forced microscopy observations. X-ray photoelectron spectroscopy analysis showed the presence of C-N and Si-N bonds in the harder films. It was found that the presence of β-C₃N₄, Si₃N₄ and graphite phases and the particle growth in the deposited films control the hardness of the film.