Relativistic Proton Production During the 14 July 2000 Solar Event: The Case for Multiple Source Mechanisms

Protons accelerated to relativistic energies by transient solar and interplanetary phenomena caused a ground-level cosmic ray enhancement on 14 July 2000, Bastille Day. Near-Earth spacecraft measured the proton flux directly and ground-based observatories measured the secondary responses to higher energy protons. We have modelled the arrival of these relativistic protons at Earth using a technique which deduces the spectrum, arrival direction and anisotropy of the high-energy protons that produce increased responses in neutron monitors. To investigate the acceleration processes involved we have employed theoretical shock and stochastic acceleration spectral forms in our fits to spacecraft and neutron monitor data. During the rising phase of the event (10:45 UT and 10:50 UT) we find that the spectrum between 140 MeV and 4 GeV is best fitted by a shock acceleration spectrum. In contrast, the spectrum at the peak (10:55 UT and 11:00 UT) and in the declining phase (11:40 UT) is best fitted with a stochastic acceleration spectrum. We propose that at least two acceleration processes were responsible for the production of relativistic protons during the Bastille Day solar event: (1) protons were accelerated to relativistic energies by a shock, presumably a coronal mass ejection (CME). (2) protons were also accelerated to relativistic energies by stochastic processes initiated by magnetohydrodynamic (MHD) turbulence.Comment: 38 pages, 9 figures, accepted for publication in the Astrophysical Journal, January, 200

A stacking-fault based microscopic model for platelets in diamond

We propose a new microscopic model for the $\{001\}$ planar defects in diamond commonly called platelets. This model is based on the formation of a metastable stacking fault, which can occur because of the ability of carbon to stabilize in different bonding configurations. In our model the core of the planar defect is basically a double layer of three-fold coordinated $sp^2$ carbon atoms embedded in the common $sp^3$ diamond structure. The properties of the model were determined using {\it ab initio} total energy calculations. All significant experimental signatures attributed to the platelets, namely, the lattice displacement along the $[001]$ direction, the asymmetry between the $[110]$ and the $[1\bar{1}0]$ directions, the infrared absorption peak $B^\prime$, and broad luminescence lines that indicate the introduction of levels in the band gap, are naturally accounted for in our model. The model is also very appealing from the point of view of kinetics, since naturally occurring shearing processes will lead to the formation of the metastable fault.Comment: 5 pages, 4 figures. Submitted for publication on August 2nd, 200

Investigation of Metallized and Nonmetallized Hydroxyl Terminated Polybutadiene/Hydrogen Peroxide Hybrid Rockets

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77070/1/AIAA-22091-612.pd

Increasing the Sensitivity of ELISA using Multiplexed Electrokinetic Concentrator

We developed a novel method to increase the sensitivity of standard enzyme-linked immunosorbent assay (ELISA) using a multiplexed electrokinetic concentration chip. The poly(dimethylsiloxane) (PDMS) molecular concentrator(1) was used to trap and collect charged fluorescent product of target-bound enzyme turnover reaction of ELISA that occurred in a standard 96 well plate. Detection sensitivities of both prostate specific antigen (PSA) and CA 19-9 (a human pancreatic and gastrointestinal cancer marker) ELISAs in serum are enhanced ~100 fold with a low CV of <17%. We also integrated this method with an on-chip bead-based ELISA that lends itself toward a fully automated on-chip diagnostic device. Detection sensitivity of microfluidic bead-based CA 19-9 ELISA in serum is enhanced ~65 fold compared to the results without the electrokinetic accumulation step. This chip can be directly applied to enhance the readout sensitivity of a wide range of existing ELISA kits at concentrations below the current detection limit.National Institutes of Health (U.S.) (CA119402)National Institutes of Health (U.S.) (EB005743

The Future of High Energy Physics Software and Computing

Software and Computing (S&C) are essential to all High Energy Physics (HEP) experiments and many theoretical studies. The size and complexity of S&C are now commensurate with that of experimental instruments, playing a critical role in experimental design, data acquisition/instrumental control, reconstruction, and analysis. Furthermore, S&C often plays a leading role in driving the precision of theoretical calculations and simulations. Within this central role in HEP, S&C has been immensely successful over the last decade. This report looks forward to the next decade and beyond, in the context of the 2021 Particle Physics Community Planning Exercise ("Snowmass") organized by the Division of Particles and Fields (DPF) of the American Physical Society.Comment: Computational Frontier Report Contribution to Snowmass 2021; 41 pages, 1 figure. v2: missing ref and added missing topical group conveners. v3: fixed typo

Mental Distress Under Occupation: The Journal of Madeleine Blaess

Madeleine Blaess a British doctoral student studying at the Sorbonne was trapped in Paris unable to return home to York for the duration of the Occupation. In October 1940 she began a diary which she kept diligently until September 1944. This unique testimony written from the perspective of a British student at liberty to roam wartime Paris, focuses more on the civilian struggle through the everyday than on the political and military situation which Blaess, vulnerable to arrest, thinks wise to mention as little as possible. This exhaustively documented, voluminous record of the minutiae of a daily struggle with material hardship discloses a struggle with mental illness articulated and managed through the writing of the diary. That diaries can have a therapeutic purpose for writers under mental strain is axiomatic and this article examines a variety of palliative strategies both deliberate and involuntary invoked through the writing process. In so doing, the article will survey the incidence and causes of civilian mental distress on the home front over the period; an area of inquiry which, other than recent work into the psychological impact of Allied bombing of civilians, has been largely neglected in recent work foregrounding and valorising the historical importance of life-writing sources in the field of Occupation studies

Relevance of nucleon spin in amplitude analysis of reactions pi(-)p->pi(0)pi(0)n and pi(-)p->eta eta n

The measurements of reactions $\pi^- p \to \pi^- \pi^+ n$ and $\pi^+ n \to \pi^+ \pi^- p$ on polarized targets at CERN found a strong dependence of pion production amplitudes on nucleon spin. Analyses of recent measurements of $\pi^- p \to \pi^0\pi^0 n$ reaction on unpolarized targets by GAMS Collaboration at 38 GeV/c and BNL E852 Collaboration at 18 GeV/c use the assumption that pion production amplitudes do not depend on nucleon spin, in conflict with the CERN results on polarized targets. We show that measurements of $\pi^- p \to \pi^0\pi^0 n$ and $\pi^- p \to \eta\eta n$ on unpolarized targets can be analysed in a model independent way in terms of 4 partial-wave intensities and 3 independent interference phases in the mass region where $S$- and $D$-wave dominate. We also describe model-independent amplitude analysis of $\pi^- p \to \pi^0\pi^0 n$ reaction measured on polarized target, both in the absence and in the presence of $G$-wave amplitudes. We suggest that high statistics measurements of reactions $\pi^- p \to \pi^0 \pi^0 n$ and $\pi^- p \to \eta\eta n$ be made on polarized targets at Protvino IHEP and at BNL, and that model-independent amplitude analyses of this polarized data be performed to advance hadron spectroscopy on the level of spin dependent production amplitudes.Comment: 54 page

Drift effects and the cosmic ray density gradient in a solar rotation period: First observation with the Global Muon Detector Network (GMDN)

We present for the first time hourly variations of the spatial density gradient of 50 GeV cosmic rays within a sample solar rotation period in 2006. By inversely solving the transport equation, including diffusion, we deduce the gradient from the anisotropy that is derived from the observation made by the Global Muon Detector Network (GMDN). The anisotropy obtained by applying a new analysis method to the GMDN data is precise and free from atmospheric temperature effects on the muon count rate recorded by ground based detectors. We find the derived north-south gradient perpendicular to the ecliptic plane is oriented toward the Helioshperic Current Sheet (HCS) (i.e. southward in the toward sector of the Interplanetary Magnetic Field (IMF) and northward in the away sector). The orientation of the gradient component parallel to the ecliptic plane remains similar in both sectors with an enhancement of its magnitude seen after the Earth crosses the HCS. These temporal features are interpreted in terms of a local maximum of the cosmic ray density at the HCS. This is consistent with the prediction of the drift model for the $A<0$ epoch. By comparing the observed gradient with the numerical prediction of a simple drift model, we conclude that particle drifts in the large-scale magnetic field play an important role in organizing the density gradient, at least in the present $A<0$ epoch. We also found that corotating interaction regions did not have such a notable effect. Observations with the GMDN provide us with a new tool for investigating cosmic ray transport in the IMF.Comment: 35 pages, 10 figures, submitted to the Astrophysical Journa