Reverse Alignment - Understanding Centerline Measurement.

Tutorialpg. 189-196Shaft alignment is a key factor in reducing vibrations and increasing reliability in rotating equipment. The most popular method of measurement is "reverse alignment." This method is often considered so complicated that many users have developed step by step worksheets, plotting boards, programmable calculators, and computer-aided laser devices that can guide the aligner through the procedure without a real understanding of the fundamentals of alignment. A need for a good understanding of the reverse method of measurement prompted this presentation. The focus herein is to show how misalignment affects the rotor's behavior. Using a back to basics graphical method, it is shown how to visualize the shaft center lines that enable the aligner to use logic for the easiest and best move. Calculation of thermal growth and how to select an allowable tolerance is also discussed. Hot alignment is presented by showing different online monitoring systems as well as how to misalign cold so that the shafts will be colinear during operation. An alignment trainer is used to demonstrate how an actual alignment is made

Equatorial locations of water on Mars: Improved resolution maps based on Mars Odyssey Neutron Spectrometer data

We present a map of the near subsurface hydrogen distribution on Mars, based on epithermal neutron data from the Mars Odyssey Neutron Spectrometer. The map’s spatial resolution is approximately improved two-fold via a new form of the pixon image reconstruction technique. We discover hydrogen-rich mineralogy far from the poles, including  ∼10 wt.% water equivalent hydrogen (WEH) on the flanks of the Tharsis Montes and  >40 wt.% WEH at the Medusae Fossae Formation (MFF). The high WEH abundance at the MFF implies the presence of bulk water ice. This supports the hypothesis of recent periods of high orbital obliquity during which water ice was stable on the surface. We find the young undivided channel system material in southern Elysium Planitia to be distinct from its surroundings and exceptionally dry; there is no evidence of hydration at the location in Elysium Planitia suggested to contain a buried water ice sea. Finally, we find that the sites of recurring slope lineae (RSL) do not correlate with subsurface hydration. This implies that RSL are not fed by large, near-subsurface aquifers, but are instead the result of either small ( < 120 km diameter) aquifers, deliquescence of perchlorate and chlorate salts or dry, granular flows

Kinetic and structure–activity studies of the triazolium ion-catalysed benzoin condensation

Steady-state kinetic and structure–activity studies of a series of six triazolium-ion pre-catalysts 2a–2f were investigated for the benzoin condensation. These data provide quantitative insight into the role of triazolium N-aryl substitution under synthetically relevant catalytic conditions in a polar solvent environment. Kinetic behaviour was significantly different to that previously reported for a related thiazolium-ion pre-catalyst 1, with the observed levelling of initial rate constants to νmax at high aldehyde concentrations for all triazolium catalysts. Values for νmax for 2a–2f increase with electron withdrawing N-aryl substituents, in agreement with reported optimal synthetic outcomes under catalytic conditions, and vary by 75-fold across the series. The levelling of rate constants supports a change in rate-limiting step and evidence supports the assignment of the Breslow-intermediate forming step to the plateau region. Correlation of νmax reaction data yielded a positive Hammett ρ-value (ρ = +1.66) supporting the build up of electron density adjacent to the triazolium N-Ar in the rate-limiting step favoured by electron withdrawing N-aryl substituents. At lower concentrations of aldehyde, both Breslow-intermediate and benzoin formation are partially rate-limiting

Forest Composition Change and Biophysical Climate Feedbacks Across Boreal North America

Deciduous tree cover is expected to increase in North American boreal forests with climate warming and wildfire. This shift in composition has the potential to generate biophysical cooling via increased land surface albedo. Here we use Landsat-derived maps of continuous tree canopy cover and deciduous fractional composition to assess albedo change over recent decades. We find, on average, a small net decrease in deciduous fraction from 2000 to 2015 across boreal North America and from 1992 to 2015 across Canada, despite extensive fire disturbance that locally increased deciduous vegetation. We further find near-neutral net biophysical change in radiative forcing associated with albedo when aggregated across the domain. Thus, while there have been widespread changes in forest composition over the past several decades, the net changes in composition and associated post-fire radiative forcing have not induced systematic negative feedbacks to climate warming over the spatial and temporal scope of our study

The core of the massive cluster merger MACS J0417.5-1154 as seen by VLT/MUSE

We present a multiwavelength analysis of the core of the massive galaxy cluster MACS J0417.5.1154 (z = 0.441). Our analysis takes advantage of Very Large Telescope/Multi-Unit Spectroscopic Explorer observations which allowthe spectroscopic confirmation of three strongly lensed systems. System #1, nicknamed The Doughnut, consists of three images of a complex ring galaxy at z = 0.8718 and a fourth, partial and radial image close to the brightest cluster galaxy (BCG) only discernible thanks to its strong [O II] line emission. The best-fitting mass model (rms of 0.38 arcsec) yields a two-dimensional enclosed mass of M(R &lt; 200 kpc) = (1.77 ± 0.03) × 10 14M ⊙ and almost perfect alignment between the peaks of the BCG light and the dark matter of (0.5 ± 0.5) arcsec. We observe a significant misalignment when system #1 radial image is omitted. The result serves as an important caveat for studies of BCG-dark-matter offsets in galaxy clusters. Using Chandra to map the intracluster gas, we observe an offset between gas and dark matter of (1.7 ± 0.5) arcsec, and excellent alignment of the X-ray peak with the location of optical emission line associated with the BCG. We interpret all observational evidences in the framework of ongoing cluster merger activity, noting specifically that the coincidence between the gas and optical line peaks may be evidence of dense, cold gas cooled directly from the intracluster gas. Finally, we measure the surface area, σ μ, above a given magnification factor μ, a metric to estimate the lensing power of a lens, σ(μ &gt; 3) = 0.22 arcmin 2, which confirms MACS J0417 as an efficient gravitational lens. </p

Second-order phase transition at the phase boundary through the FeRh first-order metamagnetic phase transition

The phase coexistence present through first-order phase transitions implies the presence of phase boundary walls, which can be of finite size. Better understanding of the phase boundary wall properties will provide an insight into the dynamics of first-order phase transitions. Here, by combining x-ray photon correlation spectroscopy investigations with magnetometry measurements of magnetic relaxation through the thermally activated first-order metamagnetic phase transition present in the B2-ordered FeRh alloy, we are able to isolate the dynamic behaviour of the phase boundary wall present in this system. These investigations reveal a change in the nature of the dynamic behaviour and critical scaling of the relaxation time centred around the point of maximum phase coexistence within the phase transition. All of this behaviour can be attributed to the introduction of exchange coupling across the phase boundary wall and raises questions about the role of latent heat in dynamic behaviour of this region

Forgotten Plotlanders: Learning from the survival of lost informal housing in the UK.

Colin Ward’s discourses on the arcadian landscape of ‘plotlander’ housing are unique documentations of the anarchistic birth, life, and death of the last informal housing communities in the UK. Today the forgotten history of ‘plotlander’ housing documented by Ward can be re-read in the context of both the apparently never-ending ‘housing crisis’ in the UK, and the increasing awareness of the potential value of learning from comparable informal housing from the Global South. This papers observations of a previously unknown and forgotten plotlander site offers a chance to begin a new conversation regarding the positive potential of informal and alternative housing models in the UK and wider Westernised world

A multicenter, randomized study of argatroban versus heparin as adjunct to tissue plasminogen activator (TPA) in acute myocardial infarction: myocardial infarction with Novastan and TPA (MINT) study

AbstractOBJECTIVESThis study examined the effect of a small-molecule, direct thrombin inhibitor, argatroban, on reperfusion induced by tissue plasminogen activator (TPA) in patients with acute myocardial infarction (AMI).BACKGROUNDThrombin plays a crucial role in thrombosis and thrombolysis. In vitro and in vivo studies have shown that argatroban has advantages over heparin for the inhibition of clot-bound thrombin and for the enhancement of thrombolysis with TPA.METHODSOne hundred and twenty-five patients with AMI within 6 h were randomized to heparin, low-dose argatroban or high-dose argatroban in addition to TPA. The primary end point was the rate of thrombolysis in myocardial infarction (TIMI) grade 3 flow at 90 min.RESULTSTIMI grade 3 flow was achieved in 42.1% of heparin, 56.8% of low-dose argatroban (p = 0.20 vs. heparin) and 58.7% of high-dose argatroban patients (p = 0.13 vs. heparin). In patients presenting after 3 h, TIMI grade 3 flow was significantly more frequent in high-dose argatroban versus heparin patients: 57.1% versus 20.0% (p = 0.03 vs. heparin). Major bleeding was observed in 10.0% of heparin, and in 2.6% and 4.3% of low-dose and high-dose argatroban patients, respectively. The composite of death, recurrent myocardial infarction, cardiogenic shock or congestive heart failure, revascularization and recurrent ischemia at 30 days occurred in 37.5% of heparin, 32.0% of low-dose argatroban and 25.5% of high-dose argatroban patients (p = 0.23).CONCLUSIONSArgatroban, as compared with heparin, appears to enhance reperfusion with TPA in patients with AMI, particularly in those patients with delayed presentation. The incidences of major bleeding and adverse clinical outcome were lower in the patients receiving argatroban

The journey so far : professional sport during the COVID-19 pandemic

BACKGROUND : The COVID-19 pandemic has profoundly impacted community and professional sports. Throughout this time, sports organisations collaborated closely with the WHO, host national governments and their public health authorities. The common goals were to assess risk and to implement risk reduction measures to facilitate a stepwise return to sport, thus realising the physical and mental health benefits of sport for the participants, as well as the safe resumption of competitive events despite active SARS-CoV-2 transmission in many countries.https://bmjopensem.bmj.comSports Medicin