Leading-edge flow criticality as a governing factor in leading-edge-vortex initiation in unsteady airfoil flows

A leading-edge suction parameter (LESP) that is derived from potential flow theory as a measure of suction at the airfoil leading edge is used to study initiation of leading-edge vortex (LEV) formation in this article. The LESP hypothesis is presented, which states that LEV formation in unsteady flows for specified airfoil shape and Reynolds number occurs at a critical constant value of LESP, regardless of motion kinematics. This hypothesis is tested and validated against a large set of data from CFD and experimental studies of flows with LEV formation. The hypothesis is seen to hold except in cases with slow-rate kinematics which evince significant trailing-edge separation (which refers here to separation leading to reversed flow on the aft portion of the upper surface), thereby establishing the envelope of validity. The implication is that the critical LESP value for an airfoil–Reynolds number combination may be calibrated using CFD or experiment for just one motion and then employed to predict LEV initiation for any other (fast-rate) motion. It is also shown that the LESP concept may be used in an inverse mode to generate motion kinematics that would either prevent LEV formation or trigger the same as per aerodynamic requirements

Violence Against Authority: Management, Policy, And Research Implications

There has been a steady decline in violent crime in the United States in the past twenty years. Trends indicate that violent crime was down 13.4 percent below the 200l level and for property crime, society is experiencing the tenth straight year of declining rates.  Yet, the Southern region of the U.S is disproportionately represented by percentage of overall violent crimes committed nationally.  Also, the South is over-represented in the number of police officers who are feloniously killed or assaulted. This empirical research concentrates on violence directed against police in the U.S. and begins by examining the type and magnitude of workplace violence, then transitions to a review of the sociological, political, and psychological literature, focusing on the individual and social causes for violence generally.  It ends with an examination of officers feloniously killed (their personal characteristics and that of their assailants), the level of violence against police by type of arrest or enforcement situation, and by region of the country.   This paper provides a comparative analysis of street-level violence for general municipal assaults, robbery, and the most rapidly growing type of felonious assault—ambush attacks. The paper concludes with an analysis of the societal and behavioral characteristics and considerations related to violence against police.  The authors present a number of current trends, training recommendations, and suggestions for improving officer workplace safety.

Near–Infrared Classification Spectroscopy: \u3ci\u3eH\u3c/i\u3e–band Spectra of Fundamental MK Standards

We present a catalog of H-band spectra for 85 stars of approximately solar abundance observed at a resolving power of 3000 with the KPNO Mayall 4 m Fourier Transform Spectrometer. The atlas covers spectral types O7M5 and luminosity classes IV as defined in the MK system. We identify both atomic and molecular indices and line ratios that are temperature and luminosity sensitive, allowing spectral classification to be carried out in the H-band. The line ratios permit spectral classification in the presence of continuum excess emission, which is commonly found in premain-sequence or evolved stars. We demonstrate that with spectra of R = 1000 obtained at signal-to-noise ratio \u3e50, it is possible to derive spectral types within ±2 subclasses for late-type stars. These data are available electronically through the Astronomical Data Center in addition to being served on the World Wide Web

Commonsense Metaphysics and Lexical Semantics

In the TACITUS project for using commonsense knowledge in the understanding of texts about mechanical devices and their failures, we have been developing various commonsense theories that are needed to mediate between the way we talk about the behavior of such devices and causal models of their operation. Of central importance in this effort is the axiomatization of what might be called commonsense metaphysics. This includes a number of areas that figure in virtually every domain of discourse, such as granularity, scales, time, space, material, physical objects, shape, causality, functionality, and force. Our effort has been to construct core theories of each of these areas, and then to define, or at least characterize, a large number of lexical items in terms provided by the core theories. In this paper we discuss our methodological principles and describe the key ideas in the various domains we are investigating

`NMR Crystallization': in-situ NMR techniques for time-resolved monitoring of crystallization processes

Solid-state NMR spectroscopy is a well-established and versatile technique for studying structural and dynamic properties of solids, and there is considerable potential to exploit the power and versatility of solid-state NMR for in-situ studies of chemical processes. However, a number of technical challenges are associated with adapting this technique for in-situ studies, depending on the process of interest. Recently, an in-situ solid-state NMR strategy for monitoring the evolution of crystallization processes has been developed and has proven to be a promising approach for identifying the sequence of distinct solid forms present as a function of time during crystallization from solution, and for the discovery of new polymorphs. The latest development of this technique, called “CLASSIC” NMR, allows simultaneous measurement of both liquid-state and solid-state NMR spectra as a function of time, thus yielding complementary information on the evolution of both the liquid phase and the solid phase during crystallization from solution. This article gives an overview of the range of NMR strategies that are currently available for in-situ studies of crystallization processes, with examples of applications that highlight the potential of these strategies to deepen our understanding of crystallization phenomena

Rationale and design of a randomized controlled clinical trial of functional electrical stimulation cycling in persons with severe multiple sclerosis

AbstractBackgroundThis randomized controlled trial (RCT) will examine the efficacy of supervised functional electrical stimulation (FES) cycling on walking performance and physiological function among persons with multiple sclerosis (MS) with severe mobility disability.Methods/designThis RCT will recruit 16 persons with MS that require unilateral or bilateral assistance for ambulation (i.e., Expanded Disability Status Scale (EDSS) score = 6.0–6.5). Participants will be randomized to one of two conditions: supervised FES cycling or passive cycling. The FES cycling condition will involve mild electrical stimulation that will generate an activation pattern that results in cycling the leg ergometer. The passive cycling condition will not provide any electrical stimulation, rather the movement of the pedals will be controlled by the electrical motor. Both conditions will be delivered 3 days/week for the same duration, over 6 months. Primary outcomes will include walking performance assessed as walking speed, endurance, and agility. Secondary outcomes will include physiological function assessed as cardiorespiratory fitness, muscular strength, and balance. Assessments will take place at baseline, mid-point (3-months), and immediately following the intervention (6-months).DiscussionThis study will lay the foundation for the design of a future RCT by: (1) providing effect sizes that can be included in a power analysis for optimal sample size estimation; and (2) identifying cardiorespiratory fitness, muscular strength, and balance (i.e., physiological function) as mechanisms for the beneficial effects of FES cycling on walking performance. This trial will provide important information on a novel exercise rehabilitation therapy for managing walking impairment in persons with severe MS

Radiation Testing Under Simulated Loca Conditions

The purpose of this evaluation is to gather data to determine whether or not radiation during a simulated Loss of Coolant Accident would have any effect upon the coatings being used. Because of the concern in industry regarding the safety of nuclear power generating stations and the strong actions of the various environmentalist clubs and agencies clubs and agencies, the utilities have been required to prove the safety of the power facilities to extraordinary degrees before licensing can be obtained to operate. One of the areas regarding the safety is the necessity of proving that the coatings will remain intact during a Loss of Coolant Accident, which could occur if the main steamline were to rupture. We have designed and built apparatus to test the performance of coatings under the conditions that might exist under such an accident criteria in order to assure ourselves and the AEC in the various utilities that the coatings currently being used or proposed will be adequate for this service. Since under these conditions the coatings would also be exposed to some radiation, the question has arisen whether or not the radiation will have any effect upon the coating during this accident condition. Tests have been run showing that radiation before or after an accident condition has no effect on the performance, but because of the difficulty in testing, little work has been done with simultaneous loss of collant and radiation. The problem is further compounded by the variety of water chemistries that are involved with various reactor designs, and the fact that many of the time-temperature criteria are so vastly different. Preliminary test results will be reported

Infarct size and left ventricular remodelling after preventive percutaneous coronary intervention

Objective: We hypothesised that, compared with culprit-only primary percutaneous coronary intervention (PCI), additional preventive PCI in selected patients with ST-elevation myocardial infarction with multivessel disease would not be associated with iatrogenic myocardial infarction, and would be associated with reductions in left ventricular (LV) volumes in the longer term. Methods: In the preventive angioplasty in myocardial infarction trial (PRAMI; ISRCTN73028481), cardiac magnetic resonance (CMR) was prespecified in two centres and performed (median, IQR) 3 (1, 5) and 209 (189, 957) days after primary PCI. Results: From 219 enrolled patients in two sites, 84% underwent CMR. 42 (50%) were randomised to culprit-artery-only PCI and 42 (50%) were randomised to preventive PCI. Follow-up CMR scans were available in 72 (86%) patients. There were two (4.8%) cases of procedure-related myocardial infarction in the preventive PCI group. The culprit-artery-only group had a higher proportion of anterior myocardial infarctions (MIs) (55% vs 24%). Infarct sizes (% LV mass) at baseline and follow-up were similar. At follow-up, there was no difference in LV ejection fraction (%, median (IQR), (culprit-artery-only PCI vs preventive PCI) 51.7 (42.9, 60.2) vs 54.4 (49.3, 62.8), p=0.23), LV end-diastolic volume (mL/m2, 69.3 (59.4, 79.9) vs 66.1 (54.7, 73.7), p=0.48) and LV end-systolic volume (mL/m2, 31.8 (24.4, 43.0) vs 30.7 (23.0, 36.3), p=0.20). Non-culprit angiographic lesions had low-risk Syntax scores and 47% had non-complex characteristics. Conclusions: Compared with culprit-only PCI, non-infarct-artery MI in the preventive PCI strategy was uncommon and LV volumes and ejection fraction were similar