Review of research in primary reading at Boston University: 1954-1959.

Thesis (Ed.M.)--Boston Universit

Future of Water for Food Conference: The Right Time and the Right Place

“All of life and all ecological processes are conditioned on the circulation of water on the planet,” said University of Nebraska President James B. Milliken, quoting from Jeffrey D. Sachs’ book Common Wealth: Economics for a Crowded Planet. “Since civilization began,” Milliken continued, “water has been central to life. We’ve established cities around it, fought wars over it, created myths about it and depended on it for food, power and transportation.” Maintaining an adequate supply of usable water has always been a challenge, but today a tangle of interrelated issues — rapid population growth, climate change, the introduction of pollutants, new water-dependent sources of energy — has created a far greater sense of urgency,” he said. “Today’s speakers, some of the best minds on the subject of water in the world, will add to our understanding of these issues and perhaps, given the scope and the severity of the challenge that faces our world, frighten us a bit.” Nebraska is a fitting place to host the Water for Food conference, Milliken said. Nebraska is one of the world’s leading agricultural centers and sits atop the High Plains aquifer, one of the largest in the world with more than 2 billion acre-feet of water in groundwater reserves; a state where the center pivot irrigation system was invented and changed the face of agriculture; a state that leads the nation in the number of irrigated acres and ranks fourth in food production. “We are a place that has been providing food for the world for a long time, and we’re acutely aware of our need to continue to improve how well we do this and that the world depends on our ability to do it,” Milliken said

The Space Physics Data System - Cosmic and Heliospheric Nodes

The Space Physics Data System (SPDS) is a community- driven network of information sources, linked and interfaced by World Wide Web software. The SPDS coordinators are community representatives to the NASA Space Physics Division, who are soliciting additional Web nodes, trying to keep the nodes organized, and soliciting information/suggestions about older data in danger of loss. Here we present a guide to data in Cosmic and Heliospheric nodes of the SPDS. New contributions to this system are being solicited and some funds may be available to assist with their development

Silicon Detector Studies with an Interferometric Thickness Mapper

A laser-interferometer system has been developed to precisely map the thickness variations of large-area silicon detectors. We describe the design and operation of the apparatus and the data processing carried out to derive thickness maps. We compare the results with a map made using accelerator beams of energetic heavy ions

Electrode Performance Test on Single Ceramic Fuel Cells Using as Electrolyte Sr‐ and Mg‐Doped LaGaO\u3csub\u3e3\u3c/sub\u3e

The electrode performance of a single solid oxide fuel cell was evaluated using a 500 μm thick La0.9Sr0.1Ga0.8Mg0.2O2.85 (LSGM) as the electrolyte membrane. Comparison of La0.6Sr0.4CoO3-δ (LSCo) and La0.9Sr0.1MnO3 (LSM) as cathodes showed LSCo gave an exchange current density two orders of magnitude higher than that of LSM. Comparison of CeO2/Ni and LSGM/Ni as anodes showed a degradation of the latter with time, and studies of the anode‐electrolyte interface and the reactivity of NiO and LSGM suggest better anode performances can be obtained with a buffer layer that prevents formation of LaNiO3 . The cell performance showed that, with a proper choice of electrode materials and LSGM as the electrolyte, a SOFC operating at temperatures 600°C \u3c Top \u3c 800°C is a realistic goal

Aharonov-Bohm cages in the GaAlAs/GaAs system

Aharonov-Bohm oscillations have been observed in a lattice formed by a two dimensional rhombus tiling. This observation is in good agreement with a recent theoretical calculation of the energy spectrum of this so-called T3 lattice. We have investigated the low temperature magnetotransport of the T3 lattice realized in the GaAlAs/GaAs system. Using an additional electrostatic gate, we have studied the influence of the channel number on the oscillations amplitude. Finally, the role of the disorder on the strength of the localization is theoretically discussed.Comment: 6 pages, 11 EPS figure

Searches for New Quarks and Leptons Produced in Z-Boson Decay

We have searched for events with new-particle topologies in 390 hadronic Z decays with the Mark II detector at the SLAC Linear Collider. We place 95%-confidence-level lower limits of 40.7 GeV/c^2 for the top-quark mass, 42.0 GeV/c^2 for the mass of a fourth-generation charge - 1/3 quark, and 41.3 GeV/c^2 for the mass of an unstable Dirac neutral lepton

Design, analysis and investigation of an independent suspension for passenger cars

The objective of this paper is the design of a front suspension. The layout used is the McPherson strut, widely adopted for road cars due to its simplicity and to the limited space required. The handling, comfort and durability of the suspension are strictly related to the position of the hardpoints, and to the elastic elements. A sensitivity analysis is carried out to investigate the roll behavior of a standard vehicle during cornering. A multi-body dynamics software is used to perform ramp-steer simulations on a full-vehicle model. Results show the different peculiarities of three specific cases of analysis, each of them emphasising the effects of a specific parameter on the whole system

Measurement of Z Decays into Lepton Pairs

We present measurements by the Mark II experiment of the ratios of the leptonic partial widths of the Z boson to the hadronic partial width. The results are Γ_(ee)/Γ_(had)=0.037_(-0.012^()+0.016),Γ_(µµ)/Γ_(had)=0.053-_(0.015)^(+0.020), and Γ_(ττ)/Γ_(had)=0.066_(-0.017)^(+0.021), in good agreement with the standard-model prediction of 0.048. From the average leptonic width result, Γ_(ll)/Γ_(had)=0.053_(-0.009)^(+0.010), we derive Γ_(had)=1.56_(-0.24)^(+0.28) GeV. We find for the vector coupling constants of the tau and muon v_τ^2=0.31±0.31_(-0.30)^(+0.43) and v_μ^2=0.05±0.30_(-0.23)^(+0.34)

Experimental investigation of the edge states structure at fractional filling factors

We experimentally study electron transport between edge states in the fractional quantum Hall effect regime. We find an anomalous increase of the transport across the 2/3 incompressible fractional stripe in comparison with theoretical predictions for the smooth edge potential profile. We interpret our results as a first experimental demonstration of the intrinsic structure of the incompressible stripes arising at the sample edge in the fractional quantum Hall effect regime.Comment: 5 pages, 5 figures included. Submitted to JETP Letter