A Note on the Supersymmetries of the Self-Dual Supermembrane

In this letter we discuss the supersymmetry issue of the self dual supermembranes in (8+1) and (4+1)-dimensions. We find that all genuine solutions of the (8+1)-dimensional supermembrane, based on the exceptional group G_2, preserve one of the sixteen supersymmetries while all solutions in (4+1)-dimensions preserve eight of them.Comment: Latex file, 12pages, no figure

Studies on tableting properties of lactose. Part III. The consolidation behaviour of sieve fractions of crystalline a-lactose\ud monohydrate

The consolidation and compaction behaviour of sieve fractions of crystalline α-lactose monohydrate were studied. From mercury porosimetry measurements tablet pore surface areas were derived. At a certain compaction load it appeared that tablets compressed from small particles were generally stronger and showed a larger surface area than compacts prepared from coarse sieve fractions. By plotting compact strength against pore surface area, a unique linear relationship was obtained. From these results it can be concluded that the actual tablet surface area, being a function of both the initial particle size and applied compaction pressure, is responsible for the compact strength

Leaveraging the continuous adjoint method for industrial scale application

One of the fastest growing fields in CFD research is adjoint optimization. Adjoint methods are widely used by people in industry to optimize their products. Drag force minimization of a car, lift force maximization of aeroplanes and minimization of power losses in ducts are some of these optimization problems. The adjoint method provides the sensitivity derivatives of the objective function (drag force etc.) with respect to the design variables (nodal displacement towards the normal direction of the surface). The calculation of the sensitivity derivatives is independent from the number of the design variables which gives the adjoint method a major advantage comparing with the other methods, especially in the problems with large design spaces

Naming of short words is (almost) the same as naming of alphanumeric symbols:Evidence from two orthographies

Throughout reading development, a gradual shift is seen in the processes underlying word identification from serial decoding toward parallel processing or sight word reading. It has been argued that this shift can be detected in the correlations between serial and discrete naming of alphanumeric symbols (digits and letters) and words. In the current study, we examined the relations between alphanumeric symbol naming and reading of monosyllabic and multisyllabic words and nonwords in two languages that differ in orthographic consistency: English and Dutch. A sample of 92 English-speaking Canadian children and 101 Dutch children, all in Grade 5, were assessed on discrete and serial naming of digits and letters and on serial and discrete naming of monosyllabic and multisyllabic words and nonwords. Results showed that discrete naming of alphanumeric symbols closely resembled discrete reading of monosyllabic words, suggesting that these words are processed in parallel in both languages. Both serial and parallel reading processes were found to underlie identification of multisyllabic words as well as monosyllabic nonwords. However, differences between the two languages emerged when processing multisyllabic nonwords. Whereas English-speaking children relied more on parallel reading processes to read multisyllabic nonwords, Dutch-speaking children processed these items serially. Theoretical implications of these findings are discusse

Optimizing the fast Rydberg quantum gate

The fast phase gate scheme, in which the qubits are atoms confined in sites of an optical lattice, and gate operations are mediated by excitation of Rydberg states, was proposed by Jaksch et al. Phys. Rev. Lett. 85, 2208 (2000). A potential source of decoherence in this system derives from motional heating, which occurs if the ground and Rydberg states of the atom move in different optical lattice potentials. We propose to minimize this effect by choosing the lattice photon frequency \omega so that the ground and Rydberg states have the same frequency-dependent polarizability \alpha(omega). The results are presented for the case of Rb.Comment: 5 pages, submitted to PR

Reductive atmospheric acid leaching of lateritic smectite/nontronite ores in H2SO4/Cu(II)/SO2 solutions

Despite the success of reductive atmospheric acid leaching (RAAL) of limonitic nickel laterite ores in recent studies limited attempt has been made to apply this method to smectite/nontronite ores of different mineralogies. A comparative study of four smectite/nontronite ores in this study showed that the use of 700 kg H2SO4/ton dry ore leaches only 74-86% Ni, 37-76% Co, 47-58% Fe and 24-66% Mn at 90 °C from slurries of 20-35% (w/w) pulp density even after 10 h, depending upon the mineralogy. These values increased to 90-97% Ni, 94-97% Co, 92-98% Mn and 72-85% Fe in the presence of Cu(II)/SO2. The first order dependence of initial fraction of iron, aluminium and nickel leached from a typical smectite ore in the first 0.5 h on the initial acid concentration provides evidence for the involvement of hydrogen ions in the surface reaction. Low activation energy of 10 kJ/mol based on the fraction of nickel leached in the first 0.5 h indicates a diffusion controlled reaction. This is supported by the applicability of a shrinking core kinetic model for metal dissolution over the first 2 h, with different apparent rate constants (kap) depending upon the iron oxide content, mineralogy and porosity. A log-log plot of kap for ores with high iron content as a function of acid concentration agrees reasonably well with the correlation already established for the leaching of nickel from limonitic laterite and manganese nodules. Thus, initial fast leaching can be related to the higher porosity and a rate controlling step which involves the diffusion of H+ through a thickening solid layer. The slow leaching at latter stages is a result of low remnant acid, thickening solid layer and changes in mineral composition

Unification Bounds on the Possible N=2 Supersymmetry Breaking Scale

In this letter, the possible appearance of N=2 supersymmetry at a low energy scale is investigated in the context of unified theories. Introducing mirror particles for all the gauge and matter multiplets of the Minimal Supersymmetric extension of the Standard Model (MSSM), the measured values of sin^2 \theta_W and \alpha_3(M_Z) indicate that the N=2 threshold scale M_{S_2} cannot be lower than \sim 10^{14}GeV. If the U(1) normalization coefficient k is treated as a free parameter, M_{S_2} can be as low as 10^9 GeV. On the other hand, if mirror quarks and leptons are absent and a non-standard value for k is used, N=2 supersymmetry breaking could in principle occur at the electroweak scale.Comment: 10 pages, LATEX, 2 eps figure

The influence of automation support on Air Traffic Controller behaviour with a Speed And Route Advisory function

The aim of this paper is to describe the influence of automation support on Air Traffic Controller performance, workload and Situation Awareness (SA). Controllers handle traffic through means of tactical control involving heading, speed and altitude instructions. Future Air Traffic Management (ATM) concepts, such as Single European Sky ATM Research (SESAR) and NextGen, promote the use of 4D trajectories, thereby introducing a time-dimension to current control tactics (SESAR, 2007). At present, Amsterdam Area Control (ACC) delivers traffic over to Schiphol Approach control (APP) via three Initial Approach Fixes (IAFs) with a margin of plus or minus 120 seconds between the planned time and the actual time. This variability can make it difficult for APP controllers to merge traffic streams and build a landing sequence, especially during peak periods. In the future, a change in delivery accuracy to less than plus or minus 30 seconds is foreseen thereby aiming to increase the punctuality of flights

Home literacy environment and early literacy development across languages varying in orthographic consistency

We examined the relation between home literacy environment (HLE) and early literacy development in a sample of children learning four alphabetic orthographies varying in orthographic consistency (English, Dutch, German, and Greek). Seven hundred and fourteen children were followed from Grade 1 to Grade 2 and tested on emergent literacy skills (vocabulary, letter knowledge, and phonological awareness) at the beginning of Grade 1 and on word reading fluency and spelling at the end of Grade 1, the beginning of Grade 2, and the end of Grade 2. Their parents responded to a questionnaire assessing HLE [parent teaching (PT), shared book reading (SBR), access to literacy resources (ALR)] at the beginning of Grade 1. Results showed first that PT was associated with letter knowledge or phonological awareness in Dutch and Greek, while ALR was associated with emergent literacy skills in all languages. SBR did not predict any cognitive or early literacy skills in any language. Second, PT and ALR had indirect effects on literacy outcomes via different emergent literacy skills in all languages. These findings suggest that not all HLE components are equally important for emergent literacy skills, reading fluency, and spelling. No specific trend in the role of orthographic consistency in the aforementioned relations emerged, which suggests that other factors may account for the observed differences across languages when children start receiving formal reading instruction in Grade 1