Skylab 4 visual observations project report

The Skylab 4 Visual Observations Project was undertaken to determine the ways in which man can contribute to future earth-orbital observational programs. The premission training consisted of 17 hours of lectures by scientists representing 16 disciplines and provided the crewmen information on observational and photographic procedures and the scientific significance of this information. During the Skylab 4 mission, more than 850 observations and 2000 photographs with the 70-millimeter Hasselblad and 35-millimeter Nikon cameras were obtained for many investigative areas. Preliminary results of the project indicate that man can obtain new and unique information to support satellite earth-survey programs because of his inherent capability to make selective observations, to integrate the information, and to record the data by describing and photographing the observational sites

Experiments with explicit filtering for LES using a finite-difference method

The equations for large-eddy simulation (LES) are derived formally by applying a spatial filter to the Navier-Stokes equations. The filter width as well as the details of the filter shape are free parameters in LES, and these can be used both to control the effective resolution of the simulation and to establish the relative importance of different portions of the resolved spectrum. An analogous, but less well justified, approach to filtering is more or less universally used in conjunction with LES using finite-difference methods. In this approach, the finite support provided by the computational mesh as well as the wavenumber-dependent truncation errors associated with the finite-difference operators are assumed to define the filter operation. This approach has the advantage that it is also 'automatic' in the sense that no explicit filtering: operations need to be performed. While it is certainly convenient to avoid the explicit filtering operation, there are some practical considerations associated with finite-difference methods that favor the use of an explicit filter. Foremost among these considerations is the issue of truncation error. All finite-difference approximations have an associated truncation error that increases with increasing wavenumber. These errors can be quite severe for the smallest resolved scales, and these errors will interfere with the dynamics of the small eddies if no corrective action is taken. Years of experience at CTR with a second-order finite-difference scheme for high Reynolds number LES has repeatedly indicated that truncation errors must be minimized in order to obtain acceptable simulation results. While the potential advantages of explicit filtering are rather clear, there is a significant cost associated with its implementation. In particular, explicit filtering reduces the effective resolution of the simulation compared with that afforded by the mesh. The resolution requirements for LES are usually set by the need to capture most of the energy-containing eddies, and if explicit filtering is used, the mesh must be enlarged so that these motions are passed by the filter. Given the high cost of explicit filtering, the following interesting question arises. Since the mesh must be expanded in order to perform the explicit filter, might it be better to take advantage of the increased resolution and simply perform an unfiltered simulation on the larger mesh? The cost of the two approaches is roughly the same, but the philosophy is rather different. In the filtered simulation, resolution is sacrificed in order to minimize the various forms of numerical error. In the unfiltered simulation, the errors are left intact, but they are concentrated at very small scales that could be dynamically unimportant from a LES perspective. Very little is known about this tradeoff and the objective of this work is to study this relationship in high Reynolds number channel flow simulations using a second-order finite-difference method

Quasi-optimal Discontinuous Galerkin discretisations of the pp-Dirichlet problem

The classical arguments employed when obtaining error estimates of Finite Element (FE) discretisations of elliptic problems lead to more restrictive assumptions on the regularity of the exact solution when applied to non-conforming methods. The so-called minimal regularity estimates available in the literature relax some of these assumptions, but are not truly of -minimal regularity-, since a data oscillation term appears in the error estimate. Employing an approach based on a smoothing operator, we derive for the first time error estimates for Discontinuous Galerkin (DG) type discretisations of non-linear problems with $(p,\delta)$-structure that only assume the natural $W^{1,p}$-regularity of the exact solution, and which do not contain any oscillation terms

Geology and petrology of the Fletcher Limestone Company Quarry, Fletcher, Henderson County, North Carolina

The Fletcher marble is a fault bounded tectonic slice positioned within the Brevard fault zone of southwestern North Carolina. A Neoproterozoic to Early-Cambrian carbonate facies within the Tallulah Falls Metamorphic Suite is proposed as a protolith to the Fletcher marble. The Fletcher marble contains a mineral assemblage consisting of dolomite + calcite + quartz + white mica ± chlorite ± talc ± tremolite ± wollastonite ± graphite. The Fletcher marble is entrained within the Brevard phyllonite. Both are polydeformed and display features associated with ductile and brittle deformation. The Fletcher marble is texturally a marble protocataclasite, however, it contains an earlier protomylonite to mylonite fabric. The earliest deformation recognized within the Fletcher marble is Late-Acadian to Early-Alleghanian mylonitization. Fabric features that display west to southwest-directed dextral shear that are observed in the Brevard phyllonite are correlated to mylonite fabrics in the Fletcher marble. Microscale cataclasis overprints this mylonite fabric, and is associated with the transition from ductile to brittle faulting. Reverse faulting, dip-slip to the northwest, is considered to represent last motion of the fault during the Late-Alleghanian. The Fletcher marble achieved amphibolite facies metamorphism prior to mylonitization as indicated by the presence of tremolite within the protomylonite fabric. Retrograde greenschist facies metamorphism, associated with Alleghanian deformation, overprints the earlier amphibolite facies features

DISCOVERY OF A NEW MAYFLY SPECIES (EPHEMEROPTERA, BAETIDAE)NEAR CENDERAWASIH UNIVERSITY CAMPUS IN PAPUA, INDONESIA

Material collected just behind the Cenderawasih University campus in Jayapura, Papua Province, Indonesia, revealed a new species of the Labiobaetis claudiae group, which is here described and illustrated based on larvae, subimago, male and female imagos. The total number of Labiobaetis species on the island New Guinea increased to 33, the total number for Indonesia increased to 26, and the total number of Labiobaetis species worldwide is augmented to 147. A key to the larvae of the L. claudiae group is provided. The interspecific K2P distances between species of the L. claudiae group are between 20% and 23%.

Childhood neurodevelopment after prescription of maintenance methadone for opioid dependency in pregnancy:a systematic review and meta-analysis

Aim: To systematically review and meta‐analyse studies of neurodevelopmental outcome of children born to mothers prescribed methadone in pregnancy. Method: MEDLINE, Embase, and PsycINFO were searched for studies published from 1975 to 2017 reporting neurodevelopmental outcomes in children with prenatal methadone exposure. Results: Forty‐one studies were identified (2283 participants). Eight studies were amenable to meta‐analysis: at 2 years the Mental Development Index weighted mean difference of children with prenatal methadone exposure compared with unexposed infants was −4.3 (95% confidence interval [CI] −7.24 to −1.63), and the Psychomotor Development Index weighted mean difference was −5.42 (95% CI −10.55 to −0.28). Seven studies reported behavioural scores and six found scores to be lower among methadone‐exposed children. Twelve studies reported visual outcomes: nystagmus and strabismus were common; five studies reported visual evoked potentials of which four described abnormalities. Factors that limited the quality of some studies, and introduced risk of bias, included absence of blinding, small sample size, high attrition, uncertainty about polydrug exposure, and lack of comparison group validity. Interpretation: Children born to mothers prescribed methadone in pregnancy are at risk of neurodevelopmental problems but risk of bias limits inference about harm. Research into management of opioid use disorder in pregnancy should include evaluation of childhood neurodevelopmental outcome

Tribopolymerization: An advanced lubrication concept for automotive engines and systems of the future

Advanced lubrication technologies based on the concept of tribopolymerization as a mechanism of boundary lubrication are described. Advantages of this approach as well as potential applications which could have an impact on the design, manufacture, and performance of existing and future automotive engines are presented and discussed. Tribopolymerization, a novel concept of molecular design developed by Furey and Kajdas, involves the continuous formation of thin polymeric films on rubbing surfaces; the protective films formed are self-replenishing. The antiwear compounds developed from this technology are effective with metals as well as ceramics and in the liquid as well as vapor phases. Furthermore, they are ashless and contain no harmful phosphorus or sulfur; and many are biodegradable. Thus, potential applications of this technology are diverse and include a variety of cost/performance/energy/environmental advantages. Examples include the following: (a) machining and cutting applications using thin films to reduce friction and ceramic tool wear; (b) the lubrication of ceramic engines (e.g., low heat rejection diesel engines) or ceramic components; (c) the development of ashless lubricants for existing and future automotive engines to reduce exhaust catalyst poisoning and environmental emissions; (d) ashless antiwear or ``lubricity`` additives for fuels, including gasoline, diesel and jet fuel; (e) vapor phase applications of this technology to high temperature gaseous systems or to fuel injector wear problems associated with the use of natural gas engines; and (f) the use of the concept of tribopolymerization as an enabling technology in the development of new engines and new automotive propulsion systems