The One-Dimensional Wigner Crystal in Carbon Nanotubes

Electron-electron interactions strongly affect the behavior of low-dimensional systems. In one dimension (1D), arbitrarily weak interactions qualitatively alter the ground state producing a Luttinger liquid (LL) 1 which has now been observed in a number of experimental systems2–6. Interactions are even more important at low carrier density, and in the limit when the long-ranged Coulomb potential is the dominant energy scale, the electron liquid is expected to become a periodically ordered solid known as the Wigner crystal7. In 1D, the Wigner crystal has been predicted to exhibit novel spin and magnetic properties not present in an ordinary LL8–12. However, despite recent progress in coupled quantum wires13, 14, unambiguous experimental demonstration of this state has not been possible due to the role of disorder. Here, we demonstrate using low-temperature single-electron transport spectroscopy that a hole gas in low-disorder carbon nanotubes with a band gap is a realization of the 1D Wigner crystal. Our observation can lead to unprecedented control over the behavior of the spatially separated system of carriers, and could be used to realize solid state quantum computing with long coherence times. Carbon nanotubes are high mobility quantum wires that may enable the study of the intrinsi

Biology

Life times of load sharing parallel systems have been considered in the statistical literature at least since Daniels (1945). The main characteristic of such a two component system is that after the failure of one component the surviving component has to shoulder extra load and hence is prone to failure at an earlier time than what is expected under the original model. In other situations, the failure of one component may release extra resources to the other, thus delaying the system failure. Gross et al (1971) observed that similar considerations affect the functioning of a two organ system. In this paper we first consider several observations schemes and identifiability issues under them. Then we construct a general semiparametric bivariate family of distributions which explicitly models this phenomenon through proportional conditional hazards. McCool (2006) has suggested a test for the hypothesis that the failures take place according to the original model against the alternative hypothesis that the second failure takes place earlie

Astronomy & Astrophysics manuscript no. (will be inserted by hand later) Vela, its X-ray nebula, and the polarization of pulsar radiation

Abstract. The recent identification of the perpendicular mode of radio polarization as the primary one in the Vela pulsar by Lai et al (2001) is interpreted in terms of the maser mechanism proposed by Luo & Melrose (1995). We suggest that such a mechanism may also be operative for the parallel mode which opens up the possibility of accounting for all types of polarization observed in pulsars. We propose an alternative interpretation of the arcs in the nebular X-radiation observed by Pavlov et al (2000) & Helfand et al (2001) with the Chandra Observatory, and interpreted by the latter as an equatorial wind. We interpret the arcs as traces of the particle beams from the two magnetic poles at the shock front. We also propose that the alignment with the rotation axis of the jet-like feature bisecting the arcs is an effect of projection on the sky plane and that there is no physical jet along the axis of rotation

Vela

be inserted by hand later

Lean Manufacturing and Productivity Improvement in Coal Mining Industry

objective of the government was to achieve high economic growth and industrialize the nation for the well-being of Indian citizens. Thus Indian market became Global and open market. Coal industry was not an exception to these phenomena of globalization. The improvement in productivity has become need of coal industry to take the competitive advantage of global marketing. Productivity improvement through Lean manufacturing means optimization and coordination of the input resources to minimize the wastes to reduce total production cost. This can be achieved by Lean thinking (to identify and eliminate wastes) and Lean Manufacturing (to improve efficiency and effectiveness of equipment). In this paper researcher has applied lean manufacturing concept in order to increase productivity of coal mining. By application of lean tools the Overall Human Effectiveness is analyzed which is converted into productive output to increase the productivity and develop an overview of the conceptual framework of lean manufacturing practices to minimize the production cost of mining

Emission Characteristics Of A Compression Ignition Engine Using Different Catalyst

Catalytic converter with different catalyst for compression ignition engine to reduce pollute gases is chosen for present work. The emphasis is given on hydrocarbon (HC), carbon monoxide (CO) and oxides of nitrogen. The catalytic converter was designed and developed with different catalyst. The pellets are developed as catalyst The pellets are coated with copper oxide (CuO), cerium oxide ( CrO2) and zirconium dioxide (ZrO2). Pellets are held together in a circular housing at two ends of the converter shell. Cylindrical spacer was used in between circular housing containing pellets to vary the distance and to reduce back pressure on the engine. Experiments were carried out on computerized kirloskar single cylinder four stroke (10 B.H.P, 7.4 KW) diesel engine test rig with an eddy current dynamometer. The converter was tested with different catalyst. There is considerable reduction in HC, CO and NOx. I

A Digital Thin Line Towed Array for Small Autonomous Underwater Platforms1

Abstract- Conventional towed arrays have been built with large diameters to allow separation of the boundary layer from the array elements so that the effect of turbulent flow has less impact on the signal to noise ratio performance of the array. These arrays, therefore, tend to be bulky and heavy. The successful development of AUV and USV required the focus of towed array development to much smaller diameter and light-weight arrays. The Acoustic Research Laboratory (ARL) of the Tropical Marine Science Institute, National University of Singapore, arising from a recent requirement, has developed a light weight Digital Thin Line Towed Array (DTLTA) for underwater sensing applications. The 10 mm diameter and 12 m long array weighing not more than 2 kg (excluding the tow cable) is a promising sensor platform for use from small autonomous assets such as AUV and USV and is believed to be the smallest diameter digital towed array ever developed. The digital output enables easy interfacing of the array to any micro-controller or PCbased data acquisition platform. A set of diagnostic and beamforming software tools were developed along with the DTLTA to help test the array. These tools are based on conventional beamforming techniques and Ronald Wagstaff's towed array diagnostics. In this paper we are presenting the details of the design and construction of the array, special features of the software tools developed and results from a tow test conducted using an AUV platform in local waters. Limitations of the current design and future development plans to improve upon them will also be discussed. I

Causal Bulk Viscous LRS Bianchi I Models With Variable Gravitational and Cosmological “Constant”

In this paper we have investigated an LRS Bianchi I anisotropic cosmological model of the universe by taking time varying G and Λ in the presence of bulk viscous fluid source described by full causal non-equilibrium thermodynamics. We obtain a cosmological constant as a decreasing function of time and for m,n> 0, the value of cosmological “constant ” for this model is found to be small and positive which is supported by the results from recent supernovae observations. Key Words: Dissipative cosmology; LRS Bianchi type I universe; Full causal theory

ASTRONOMY AND ASTROPHYSICS

A&A manuscript no. (will be inserted by hand later) Your thesaurus codes are

ASTRONOMY AND ASTROPHYSICS

in neutron star