Autonomous control of underground mining vehicles using reactive navigation

Describes how many of the navigation techniques developed by the robotics research community over the last decade may be applied to a class of underground mining vehicles (LHDs and haul trucks). We review the current state-of-the-art in this area and conclude that there are essentially two basic methods of navigation applicable. We describe an implementation of a reactive navigation system on a 30 tonne LHD which has achieved full-speed operation at a production mine

On hydrogen bond correlations at high pressures

In situ high pressure neutron diffraction measured lengths of O H and H O pairs in hydrogen bonds in substances are shown to follow the correlation between them established from 0.1 MPa data on different chemical compounds. In particular, the conclusion by Nelmes et al that their high pressure data on ice VIII differ from it is not supported. For compounds in which the O H stretching frequencies red shift under pressure, it is shown that wherever structural data is available, they follow the stretching frequency versus H O (or O O) distance correlation. For compounds displaying blue shifts with pressure an analogy appears to exist with improper hydrogen bonds.Comment: 12 pages,4 figure

High pressure investigations on hydrous Magnesium Silicate-Phase A using first principles calculations, H---H repulsion and O-H bond compression

We have carried out first principles structural relaxation calculations on the hydrous magnesium silicate Phase A (Mg7Si2O8(OH)6) under high pressures. Our results show that phase A does not undergo any phase transition upto ~ 45 GPa. We find that nonbonded H---H distance reaches a limiting value of 1.85 Å at about 45 GPa. The H---H repulsive strain releasing mechanism in Phase A is found to be dramatically different from the hydrogen bond bending one that was proposed by Hofmeister et al1 for Phase B. It is based on the reduction of one of the O-H bond distances with compression

Development of promiscous rhizobia for diverse rabi legumes (Chickpea, Pea and Lentil)

Conjugation between microsymbiont was used to create genetic variations in rhizobia for diverse rabi legumes (chickpea, pea and lentil) with better characteristics in nodulation and nitrogen fixation process. Ten antibiotics were used as selectable markers for the screening of twenty four bacterial strains to be used in mating experiments for obtaining transconjugants. All bacterial strains were sensitive to gentamycin and resistant to streptomycin, kanamycin and sulphanilamide. Total five fusants were obtained from each rhizobial cross combination with the help of electro-poration. Modified transconjugants, rhizobial strains had promiscuous infection with 50-122% more nodules showed significant increase in shoot fresh weight, dry weight and total nitrogen content in chickpea, pea and lentil plants. Electrofusantsrhizobial strains improved shoot nitrogen content up to 67% in lentil and 54% in pea and chickpea plants. The amount of nitrogen fixed in chickpea was highest (3.71gm) by transconjugants DP-C6- HLN followed by DP-C6-HP14 (3.56gm). Transconjugants DP-HP14-HLN fixed the highest amount of nitrogen (3.92gm) in pea and 4.06gm in lentil plants. Plasmids were also analyzed in order to characterize their role in the evolution of rhizobial symbionts and their involvement in symbiotic behaviour. The developed Rhizobium strains with improved symbiotic association and ability to infect across strict specificity for host legumes would be of great help for the farming community at large

Vaginal delivery in a patient with asymptomatic severe aortic stenosis: a case report

Heart disease complicates about 1-4% of all pregnancies of which valvular heart disease is the commonest cause. In developing countries, congenital heart diseases are commonly first detected during pregnancy. Most women do well during pregnancy but severe mitral stenosis or severe aortic stenosis are high-risk conditions that can cause significant morbidity and mortality. Unlike asymptomatic severe mitral stenosis, asymptomatic severe aortic stenosis is mWHO category 3. There is no consensus on the mode of delivery in patients with asymptomatic severe aortic stenosis. Here we describe a case of successful vaginal delivery in a woman with severe aortic stenosis. As the patient was asymptomatic and ejection fraction was preserved, a joint decision for vaginal delivery was taken along with the cardiology team. The patient was induced and delivered with operative vaginal delivery. This case shows that vaginal delivery could be a viable option in patients with asymptomatic severe aortic stenosis given continuous haemodynamic monitoring can be provided

The use of mobile phone cameras in guiding treatment decisions for laceration care

Objectives: Mobile phone technology may be useful in helping to guide medical decisions for lacerations. We examined whether emergency department (ED) provider opinions on which lacerations require repair differed using mobile phone–generated images compared with in-person evaluations. Subjects and Methods: Patients presenting to an urban ED for initial and follow-up laceration care were prospectively enrolled. Patients took four mobile phone pictures of their laceration and provided a medical history. Cases were reviewed by ED providers who assessed image quality and made a recommendation about whether the laceration needed repair. The same provider then assessed the patient in-person. Concordant decision-making between mobile phone and in-person assessments was calculated as well as the degree of undertriage. Results: In total, 94 patients were included over an 8-month period. There was complete agreement in 87% of cases (κ statistic=0.65). Of the 13 patients with discrepant decisions, 6 were due to poor image quality, in 3 the images did not properly represent the problem, in 3 others there were historical findings that altered care, and for 1 the image looked worse than the actual injury in-person. In total, 5 of 94 (5%) of cases would have been undertriaged using only the mobile phone recommendation. Median image quality was 6 out of 10 (with 10 being the best) (interquartile range, 4–8). Conclusions: There are high rates of agreement when providers use mobile phone images to assess lacerations for possible repair in the ED. Image quality is in general good but highly variable and may drive incorrect assessments

Structure determination of Ls-threonine by neutron diffraction

The structure of the aminoacid, Ls-threonine [NH 3 + CH(CHOHCH3)COO-], space groupP212121,a=13.630(5),b=7.753(1),c=5.162(2) Å ,z=4, has been determined from neutron diffraction data using direct methods. The intensities of 1148 neutron Bragg reflections were measured from a single crystal. The structural parameters were refined by the method of least squares using anisotropic temperature factors. The finalR(F 2) is 0.068. The structure was also refined from the x-ray data of Shoemakeret al (1950J. Am. Chem. Soc. 72 2328); there is good agreement between the two sets of heavy atom parameters. The parameters of hydrogen atoms are of course more precisely determined in our neutron study. The molecular conformation and the hydrogen bonding scheme are discussed. Weighted average values of bond distances and angles from 14 aminoacid structures with ionized carboxylic groups studied by neutron diffraction at Brookheven and Trombay are also presented

Cavity radius estimation for contained peaceful nuclear explosions-an analytic approach

An analytical method based on Penny-Taylor model has been modified and applied for the estimation of the final cavity radius for contained peaceful nuclear explosions. The calculated cavity radii for some nuclear explosions in granite, alluvium and sandstone rocks are in good agreement with measured values

Pressure-induced alpha-to-omega transition in titanium metal: A systematic study of the effects of uniaxial stress

We investigated the effects of uniaxial stress on the pressure-induced alpha-to-omega transition in pure titanium (Ti) by means of angle dispersive x-ray diffraction in a diamond-anvil cell. Experiments under four different pressure environments reveal that: (1) the onset of the transition depends on the pressure medium used, going from 4.9 GPa (no pressure medium) to 10.5 GPa (argon pressure medium); (2) the a and w phases coexist over a rather large pressure range, which depends on the pressure medium employed; (3) the hysteresis and quenchability of the w phase is affected by differences in the sample pressure environment; and (4) a short term laser-heating of Ti lowers the alpha-to-omega transition pressure. Possible transition mechanisms are discussed in the light of the present results, which clearly demonstrated the influence of uniaxial stress in the alpha-to-omega transition.Comment: 16 pages, 6 figures, 1 tabl