Doppler sodar observations of the winds and structure in the lower atmosphere over Fairbanks, Alaska

Thesis (M.S.) University of Alaska Fairbanks, 2007Fairbanks, Alaska (64°49ʹ N, 147°52ʹ W) experiences strong temperature inversions which when combined with the low wind speeds prevailing during the winter cause serious air pollution problems. The SODAR (Sound Detection And Ranging) or acoustic sounder is a very useful instrument for studying the lower atmosphere as it can continuously and reliably measure the vertical profiles of wind speed and direction,vertical motions, turbulence and the thermal structure in the lower part of the troposphere. A Doppler sodar was operated from December 2005 to April 2006 at the National Weather Service site in Fairbanks. The wind observations from the sodar indicate that the majority of the winds during the winter months were from the North, Northeast or the East, which is in good agreement with the radiosonde measurements and the long term trends in the wind patterns over Fairbanks area. Case studies were carried out using the sodar data depicting drainage winds, low-level jets, formation and breakup of inversions and estimation of the mixing layer height.1. Introduction -- 1.1. Climatic features in Fairbanks during winter -- 1.1.1. Temperature inversions -- 1.1.2. Valley winds and drainage winds -- 1.1.3. Urban heat island -- 1.1.4. Air pollution and ice fog -- 1.2. SODAR and its applications -- 1.2.1 Acoustic sounder observations at Fairbanks in the past -- 2. Theory and instrumentation 2.1. Estimation of Ct² -- 2.1.1. Scattering theory -- 2.1.2. Sodar equation -- 2.2. Wind speed and direction -- 2.3. Sodar installation and data acquisition -- 2..4. Sodar dataset and additional sources of data -- 2.5. Algorithm to detect strong layers of temperature inversion -- 3. Results and discussion -- 3.1. Results from the inversion detection algorithm -- 3.1.1. Diurnal variations in inversion characteristics -- 3.1.2. Effect of cloud cover on inversion characteristics -- 3.2. Wind observations from sodar data -- 3.3. Case studies from sodar observations -- 3.3.1. Drainage winds overflowing the stable layer of air beneath -- 3.3.2. Nocturnal jet associated with a temperature inversion -- 3.3.3. Destruction of an inversion due to forced mixing and increasing cloud cover -- 3.3.4. Estimation of the mixing layer height from the backscatter intensity -- 4. Conclusions and future work -- References

Measurement of residual stresses in a dissimilar metal welded pipe

Dissimilar metal welds (DMW) are used in light water reactor power plants to join ferritic and austenitic steel piping components. High residual stresses remaining in this type of welded joint can significantly increase its susceptibility to stress corrosion cracking (SCC) under water reactor chemistry conditions. This degradation mechanism has compromised the integrity of many nuclear power plants throughout the world over the past 10 years. The Open University (OU) is undertaking a programme of research aimed at improving the reliability of residual stress measurements in DMWs using neutron diffraction. AREVA, the French nuclear power plant constructor, has developed an improved narrow gap DMW weld using a nickel-based corrosion resistant filler (alloy-52) to eliminate the risk of SCC in next generation nuclear plant. Through-wall neutron measurements have been carried out on a full-size DMW mock-up (352 mm OD, 40 mm thick) using the ENGIN-X instrument at the ISIS Facility in the UK. The results have shown that the largest tensile stress components in the welded component lie in the hoop direction, and have values of around 250 MPa and 225 MPa in the austenitic and alloy-52 materials respectively. These measured stresses were in reasonable agreement with those obtained from deep-hole drilling and numerical simulations. A notable finding in the experimental work was a wide scatter in the measured unstressed lattice parameters within a range equivalent to micro-strains of ≈ 430, 400 and 600 for austenitic stainless steel, ferritic steel and alloy-52 respectively. This scatter was reduced by two orders of magnitude through making additional measurements whilst slowly rotating the stress-free reference cubes. The OU is undertaking systematic studies to identify the origins of the observed measurement scatter in order to improve the reliability of measurements

Magnetorheological Elastomers: Experiments and Modeling

National audienceMagnetorheological elastomers (MREs) are ferromagnetic particle impregnated elastomers whose mechanical properties are altered by the application of external magnetic fields. Due to their magnetoelastic coupling response MREs are finding an increasing number of engineering applications. The objective of this work is : (a) the experimental study of transversely isotropic MREs (i.e., the particles form chains along a certain direction) that are subjected to prestressing and arbitrary magnetic fields and (b), the phenomenological modeling of these materials using transversely isotropic energy functions.See http://hal.archives-ouvertes.fr/docs/00/59/26/92/ANNEX/r_NHEKI0N4.pd

A simple contact mapping algorithm for identifying potential peptide mimetics in protein–protein interaction partners

A simple, static contact mapping algorithm has been developed as a first step at identifying potential peptide biomimetics from protein interaction partner structure files. This rapid and simple mapping algorithm, “OpenContact” provides screened or parsed protein interaction files based on specified criteria for interatomic separation distances and interatomic potential interactions. The algorithm, which uses all-atom Amber03 force field models, was blindly tested on several unrelated cases from the literature where potential peptide mimetics have been experimentally developed to varying degrees of success. In all cases, the screening algorithm efficiently predicted proposed or potential peptide biomimetics, or close variations thereof, and provided complete atom-atom interaction data necessary for further detailed analysis and drug development. In addition, we used the static parsing/mapping method to develop a peptide mimetic to the cancer protein target, epidermal growth factor receptor. In this case, secondary, loop structure for the peptide was indicated from the intra-protein mapping, and the peptide was subsequently synthesized and shown to exhibit successful binding to the target protein. The case studies, which all involved experimental peptide drug advancement, illustrate many of the challenges associated with the development of peptide biomimetics, in general

Quasi-Bayes in Latent Variable Models

Latent variable models are widely used to account for unobserved determinants of economic behavior. Traditional nonparametric methods to estimate latent heterogeneity do not scale well into multidimensional settings. Distributional restrictions alleviate tractability concerns but may impart non-trivial misspecification bias. Motivated by these concerns, this paper introduces a quasi-Bayes approach to estimate a large class of multidimensional latent variable models. Our approach to quasi-Bayes is novel in that we center it around relating the characteristic function of observables to the distribution of unobservables. We propose a computationally attractive class of priors that are supported on Gaussian mixtures and derive contraction rates for a variety of latent variable models

Scar endometriosis: a mystery entity

Scar Endometriosis is described as having an active endometrial tissue at the scar area outside the uterine cavity. Corner stone for diagnosis is proper history, clinical examination and suspicion-based imaging. Caesarean scar endometriosis (CSE) usually seen following procedures like caesarean sections, hysterectomies. Time of presentation can be very variable so yet times difficult to suspect. Once suspected Convincing patient that they have active glands other than in uterine cavity is not easy. Hence proper imaging and biopsy is needed to backup for thorough counselling and treatment to improve the quality of life

Large pelvic mass - careful planning - can decrease the morbidity

We report a case of a 43-year old woman with a 24-26 weeks size pelvic mass, inspite of CT contrast pelvis the exact location of mass remained unclear. At laparotomy, it was found to be a broad ligament multilobulated leiomyoma measuring 20-24cm and weighing, approximately 1400gms. We are reporting this to emphasize the importance of planning a case and involving different team members in case of large mass with an anticipation of complications and also a pathologist a day prior about the need for frozen section

Characterizing the oligomeric structure and catalytic activity of the dihydroorotase and aspartate transcarbamoylase from the bacterium, \u3ci\u3ebacillus anthracis\u3c/i\u3e

Bacteremia refers to bacterial presence in the blood. Bacterial proliferation in the blood requires that the organism adapt its metabolism to available nutrients. Nucleotide precursors that could be used are present at low levels in the blood, and thus the invading bacteria must rely on de novo nucleotide biosynthesis for survival. The dihydroorotase domain is a key enzyme in pyrimidine biosynthesis and a promising drug target. The genes encoding the dihydroorotase (DHOase) and aspartate transcarbamoylase (ATCase) of Bacillus anthracis (B. anthracis) were cloned for expression in Escherichia coli (E. coli). The proteins were purified by affinity chromatography and the enzymatic activity was determined by enzyme assays. The data suggests that a physical and functional interaction exists. The activity of ATCase was increased by about 2 fold in the presence of an equimolar concentration of DHOase. An ATCase-DHOase complex was formed as judged by S-300 gel filtration chromatography and cross-linking methods. Moreover, orotate was found to be an effective inhibitor of the DHOase activity at nanomolar concentrations. These results bring us closer to understanding the structural organization of the pyrimidine pathway in the pathogenic B. anthracis bacterium and provide a lead in the design of drugs selective to the bacteria

A challenging case of SLE associated with intrahepatic cholestasis and atypical Wilson's disease

We herewith present a case of SLE which reflects that appropriate Multidisciplinary approach gives good outcome inspite of risk factors including prematurity. Systemic lupus erythematosus (SLE) an autoimmune disease in itself a high-risk factor along with intrahepatic cholestasis and atypical wilson's disease it’s a tough journey for clinicians as well as the family but good timely intervention by appriopriate investigations gave an excellent outcome. Emergency LSCS was performed for pathological CTG at 31 weeks, mother and child followed up for a year and a half then we are reporting this case