Study of a relaxed'' ALS storage ring lattice

The lattice of the Advanced Light Source (ALS) 1--1.9 GeV electron storage ring was reexamined, introducing an additional family of focusing quadrupoles and looking for a working point with larger dynamic aperture. In the first part of this study, the ideal lattice was investigated to confirm the anticipated behavior, and indeed conditions with increased dynamic aperture were found. In the second part, realistic magnet errors and an undulator in one of the straight sections were taken into account. Under these conditions the dynamic aperture could not be significantly improved over the nominal configuration. Further studies included investigation of the Touschek momentum acceptance of the lattice. In this case too, no net benefit was obtained from the additional quadrupoles. 6 refs., 5 figs. , 2 tabs

A Cost-Effective Design for a Neutrino Factory

There have been active efforts in the U.S., Europe, and Japan on the design of a Neutrino Factory. This type of facility produces intense beams of neutrinos from the decay of muons in a high energy storage ring. In the U.S., a second detailed Feasibility Study (FS2) for a Neutrino Factory was completed in 2001. Since that report was published, new ideas in bunching, cooling and acceleration of muon beams have been developed. We have incorporated these ideas into a new facility design, which we designate as Study 2B (ST2B), that should lead to significant cost savings over the FS2 design.Comment: 46 pages, 38 figures; to be submitted to Physical Review Special Topics: Accelerators and Beam

Effect of Particle Size on Droplet Infiltration into Hydrophobic Porous Media As a Model of Water Repellent Soil

The wettability of soil is of great importance for plants and soil biota, and in determining the risk for preferential flow, surface runoff, flooding,and soil erosion. The molarity of ethanol droplet (MED) test is widely used for quantifying the severity of water repellency in soils that show reduced wettability and is assumed to be independent of soil particle size. The minimum ethanol concentration at which droplet penetration occurs within a short time (≤10 s) provides an estimate of the initial advancing contact angle at which spontaneous wetting is expected. In this study, we test the assumption of particle size independence using a simple model of soil, represented by layers of small (0.2–2 mm) diameter beads that predict the effect of changing bead radius in the top layer on capillary driven imbibition. Experimental results using a three-layer bead system show broad agreement with the model and demonstrate a dependence of the MED test on particle size. The results show that the critical initial advancing contact angle for penetration can be considerably less than 90° and varies with particle size, demonstrating that a key assumption currently used in the MED testing of soil is not necessarily valid

Optimized Two-Baseline Beta-Beam Experiment

We propose a realistic Beta-Beam experiment with four source ions and two baselines for the best possible sensitivity to theta_{13}, CP violation and mass hierarchy. Neutrinos from 18Ne and 6He with Lorentz boost gamma=350 are detected in a 500 kton water Cerenkov detector at a distance L=650 km (first oscillation peak) from the source. Neutrinos from 8B and 8Li are detected in a 50 kton magnetized iron detector at a distance L=7000 km (magic baseline) from the source. Since the decay ring requires a tilt angle of 34.5 degrees to send the beam to the magic baseline, the far end of the ring has a maximum depth of d=2132 m for magnetic field strength of 8.3 T, if one demands that the fraction of ions that decay along the straight sections of the racetrack geometry decay ring (called livetime) is 0.3. We alleviate this problem by proposing to trade reduction of the livetime of the decay ring with the increase in the boost factor of the ions, such that the number of events at the detector remains almost the same. This allows to substantially reduce the maximum depth of the decay ring at the far end, without significantly compromising the sensitivity of the experiment to the oscillation parameters. We take 8B and 8Li with gamma=390 and 656 respectively, as these are the largest possible boost factors possible with the envisaged upgrades of the SPS at CERN. This allows us to reduce d of the decay ring by a factor of 1.7 for 8.3 T magnetic field. Increase of magnetic field to 15 T would further reduce d to 738 m only. We study the sensitivity reach of this two baseline two storage ring Beta-Beam experiment, and compare it with the corresponding reach of the other proposed facilities.Comment: 17 pages, 3 eps figures. Minor changes, matches version accepted in JHE

Interior and edge magnetization in thin exfoliated CrGeTe3 films

CrGeTe3 (CGT) is a semiconducting vdW ferromagnet shown to possess magnetism down to a two-layer thick sample. Although CGT is one of the leading candidates for spintronics devices, a comprehensive analysis of CGT thickness dependent magnetization is currently lacking. In this work, we employ scanning SQUID-on-tip (SOT) microscopy to resolve the magnetic properties of exfoliated CGT flakes at 4.2 K. Combining transport measurements of CGT/NbSe2 samples with SOT images, we present the magnetic texture and hysteretic magnetism of CGT, thereby matching the global behavior of CGT to the domain structure extracted from local SOT magnetic imaging. Using this method, we provide a thickness dependent magnetization state diagram of bare CGT films. No zero-field magnetic memory was found for films thicker than 10 nm and hard ferromagnetism was found below that critical thickness. Using scanning SOT microscopy, we identify a unique edge magnetism, contrasting the results attained in the CGT interior.Comment: Main text: 15 pages, 5 figures. Supplementary information: 9 pages, 10 figures. Supplementary videos:

Novel computed tomographic chest metrics to detect pulmonary hypertension

<p>Abstract</p> <p>Background</p> <p>Early diagnosis of pulmonary hypertension (PH) can potentially improve survival and quality of life. Detecting PH using echocardiography is often insensitive in subjects with lung fibrosis or hyperinflation. Right heart catheterization (RHC) for the diagnosis of PH adds risk and expense due to its invasive nature. Pre-defined measurements utilizing computed tomography (CT) of the chest may be an alternative non-invasive method of detecting PH.</p> <p>Methods</p> <p>This study retrospectively reviewed 101 acutely hospitalized inpatients with heterogeneous diagnoses, who consecutively underwent CT chest and RHC during the same admission. Two separate teams, each consisting of a radiologist and pulmonologist, blinded to clinical and RHC data, individually reviewed the chest CT's.</p> <p>Results</p> <p>Multiple regression analyses controlling for age, sex, ascending aortic diameter, body surface area, thoracic diameter and pulmonary wedge pressure showed that a main pulmonary artery (PA) diameter ≥29 mm (odds ratio (OR) = 4.8), right descending PA diameter ≥19 mm (OR = 7.0), true right descending PA diameter ≥ 16 mm (OR = 4.1), true left descending PA diameter ≥ 21 mm (OR = 15.5), right ventricular (RV) free wall ≥ 6 mm (OR = 30.5), RV wall/left ventricular (LV) wall ratio ≥0.32 (OR = 8.8), RV/LV lumen ratio ≥1.28 (OR = 28.8), main PA/ascending aorta ratio ≥0.84 (OR = 6.0) and main PA/descending aorta ratio ≥ 1.29 (OR = 5.7) were significant predictors of PH in this population of hospitalized patients.</p> <p>Conclusion</p> <p>This combination of easily measured CT-based metrics may, upon confirmatory studies, aid in the non-invasive detection of PH and hence in the determination of RHC candidacy in acutely hospitalized patients.</p

The ethics of synthetic biology research and development:a principlist approach

A principlist approach is adopted to analyse the ethical status of synthetic biology (synbio) research and development. The principle of nonmaleficence generates precaution-driven conclusions that are excessively restrictive to the field of synbio. The principle of beneficence is best served by permitting synbio research to flourish and not have it treated as a special case warranting the imposition of a high degree of external and self-regulation. Synbio may offend the principle of justice in certain circumstances; however, such issues are largely restricted to the initial stages of synbio innovation, whilst in the longer term the development of the field can be expected to promote just ends. The principle of respect for autonomy entails that scientists ought to be afforded a broad scope to freely pursue synbio research and development in a curiosity-driven fashion. In balancing the various conclusions under the four principles, the author concludes that society has an ethical obligation to support the development of synbio research and development and not restrict this important nascent field by the imposition of stern regulation

INVESTIGATION OF CRYSTALLOGRAPHIC FEATURES IN BAINITEMARTENSITE STRUCTURES AFTER DIFFERENT QUENCHING CONDITIONS BY MEANS OF EBSD-ANALYSIS

Методом EBSD-анализа исследовали влияние температуры закалки на кристаллографические особенности бейнитно-мартенситной структуры образцов из высокопрочной низкоуглеродистой стали. Показано, что закалка с более высокой температуры снижает долю большеугловых границ, но практически не меняет спектр межвариантных разориентировок. В то же время этот спектр заметно изменяется с повышением скорости охлаждения, что обусловлено ростом доли мартенситной составляющей.The influence of quenching temperature on crystallographic features in bainite-martensite structure of high strength low alloyed steel is under research. Higher quenching temperature decreases high-angle boundaries fraction whereas intervariant misorientations distribution are invariable. At the same time the intervariant misorientations distribution alters significantly at increasing cooling rate due to martensite fraction increase.Работа выполнена при финансовой поддержке государства в лице Минобрнауки в рамках соглашения № 14.595.21.0004