How Saturated are Absorption Lines in the Broad Absorption Line Quasar PG 1411+442 ?

Recently, convincing evidence was found for extremely large X-ray absorption by column densities $> 10^{23} cm^{-2}$ in broad absorption line quasars. One consequence of this is that any soft X-ray emission from these QSOs would be the scattered light or leaked light from partially covering absorbing material. A detection of the unabsorbed soft X-ray and absorbed hard X-ray compo nent will allow to determine the total column density as well as the effective covering factor of the absorbing material, which can be hardly obtained from the UV absorption lines. Brinkmann et al. (1999) showed that both the unabsorbed and absorbed components are detected in the nearby very bright broad absorption line quasar PG 1411+442. In this letter, we make a further analysis of the broad band X-ray spectrum and the UV spectrum from HST, and demonstrate that broad absorption lines are completely saturated at the bottom of absorption troughs.Comment: 6 pages, 3 postscript figures. to appear in Astrophy. J. Letter

Relationships of the Genera \u3ci\u3eAcanthametropus, Analetris,\u3c/i\u3e and \u3ci\u3eSiphluriscus\u3c/i\u3e, and Re-Evaluation of Their Higher Classification (Ephemeroptera: Pisciforma)

The historical higher classification of the genera Acanthametropus Tshernova, Analetris Edmunds, and Siphluriscus Ulmer is reviewed. The first comprehensive generic description of Siphluriscus is given, and first figures of wings are provided. A cladistic analysis of adult and larval characters of Acanthametropus and Analetris. and adult characters of Siphluriscus reveal a close relationship between the former two genera, which represent a well-defined clade based on five identified synapomorphies; however, Siphluriscus, which has been classified with them in the past, does not share any apomorphies with them but instead shares apomorphies with the genera of Siphlonuridae sensu stricto. Acanthametropus and Analetris are recombined in the family Acanthametropodidae, suppressing Analetrididae; and Siphluriscus is reassigned to the family Siphlonuridae sensu stricto, although taxon rank for both of these clades is still tentative and awaits comparative cladistic analysis of the entire suborder Pisciforma. The relationship to each other of these clades also remains in doubt. Stackelbergisca Tshernova, a fossil genus formerly classified with the three extant genera apparently does not share any of the 11 apomorphies used in this study, and is placed as family incertae within the Pisciforma

Adaptive control of CO2_2 bending vibration: deciphering field-system dynamics

We combined adaptive closed-loop optimization, phase-shaping with a restricted search space and imaging to control dynamics and decipher the optimal pulse. The approach was applied to controlling the amplitude of CO$_2$ bending vibration during strong-field Coulomb explosion. The search space was constrained by expressing the spectral phase as a Taylor series, which generated pulses with characteristics commensurate with the natural physical features of this problem. Optimal pulses were obtained that enhanced bending by up to 56% relative to what is observed with comparably intense, transform limited pulses. We show that (1) this judicious choice of a reduced parameter set made unwrapping the dynamics more transparent and (2) the enhancement is consistent with field-induced structural changes to a bent excited state of CO$_2^{2+}$, which theoretical simulations have identified as the state from which the explosion originates.Comment: 4 pages, 3 figures, 1 table, added reference

Dynamic Response of a Cylindrical Shell Segment Subjected to an Arbitrary Loading

Dynamic response analysis for underground cylindrical shell segments subjected to blast loadin

State-of-the-art on research and applications of machine learning in the building life cycle

Fueled by big data, powerful and affordable computing resources, and advanced algorithms, machine learning has been explored and applied to buildings research for the past decades and has demonstrated its potential to enhance building performance. This study systematically surveyed how machine learning has been applied at different stages of building life cycle. By conducting a literature search on the Web of Knowledge platform, we found 9579 papers in this field and selected 153 papers for an in-depth review. The number of published papers is increasing year by year, with a focus on building design, operation, and control. However, no study was found using machine learning in building commissioning. There are successful pilot studies on fault detection and diagnosis of HVAC equipment and systems, load prediction, energy baseline estimate, load shape clustering, occupancy prediction, and learning occupant behaviors and energy use patterns. None of the existing studies were adopted broadly by the building industry, due to common challenges including (1) lack of large scale labeled data to train and validate the model, (2) lack of model transferability, which limits a model trained with one data-rich building to be used in another building with limited data, (3) lack of strong justification of costs and benefits of deploying machine learning, and (4) the performance might not be reliable and robust for the stated goals, as the method might work for some buildings but could not be generalized to others. Findings from the study can inform future machine learning research to improve occupant comfort, energy efficiency, demand flexibility, and resilience of buildings, as well as to inspire young researchers in the field to explore multidisciplinary approaches that integrate building science, computing science, data science, and social science

Morphology investigation on direct current pulsed gas tungsten arc welded additive layer manufactured Ti6Al4V alloy

The effects of pulsed gas tungsten arc weldingparameters on the morphology of additive layer manufacturedTi6Al4V has been investigated in this study. Thepeak/ base current ratio and pulse frequency are found tohave no significant effect on the refinement of prior betagrain size. However, it is found that the wire feed ratehas a considerable effect on the prior beta grainrefinement at a given heat input. This is due to the extrawire input being able to supply many heterogeneousnucleation sites and also results in a negative temperaturegradient in the front of the liquidus which blocks thecolumnar growth and changes the columnar growth toequiaixal growth

Gravitational-Wave Implications for the Parity Symmetry of Gravity at GeV Scale

Gravitational waves generated by the coalescence of compact binary open a new window to test the fundamental properties of gravity in the strong-field and dynamical regime. In this work, we focus on the parity symmetry of gravity which, if broken, can leave imprints on the waveform of gravitational wave. We construct generalized waveforms with amplitude and velocity birefringence due to parity violation in the effect field theory formalism, then analyze the open data of the ten binary black-hole merger events and the two binary neutron-star merger events detected by LIGO and Virgo collaboration. We do not find any signatures of violation of gravitational parity conservation, thereby setting the lower bound of the parity-violating energy scale to be $0.07$ GeV. This presents the first observational evidence of the parity conservation of gravity at high energy scale, about 17 orders of magnitude tighter than the constraints from the Solar system tests and binary pulsar observation. The third-generation gravitational-wave detector is capable of probing the parity-violating energy scale at $\mathcal{O}(10^2)$ GeV