Asymmetric Squares as Standing Waves in Rayleigh-Benard Convection

Possibility of asymmetric square convection is investigated numerically using a few mode Lorenz-like model for thermal convection in Boussinesq fluids confined between two stress free and conducting flat boundaries. For relatively large value of Rayleigh number, the stationary rolls become unstable and asymmetric squares appear as standing waves at the onset of secondary instability. Asymmetric squares, two dimensional rolls and again asymmetric squares with their corners shifted by half a wavelength form a stable limit cycle.Comment: 8 pages, 7 figure

Precursors to potential severe core damage accidents. A status report, 1982--1983

This study is a continuation of earlier work that evaluated 1969-1981 and 1984-1994 events affecting commercial light-water reactors. One-hundred nine operational events that affected 51 reactors during 1982 and 1983 and that are considered to be precursors to potential severe core damage are described. All these events had conditional probabilities of subsequent severe core damage greater than or equal to 1.0 x 10{sup {minus}6}. These events were identified by first computer screening the 1982-83 licensee event reports from commercial light-water reactors to select events that could be precursors to core damage. Candidates underwent engineering evaluation that identified, analyzed, and documented the precursors. This report discusses the general rationale for the study, the selection and documentation of events as precursors, and the estimation of conditional probabilities of subsequent severe core damage for the events

CIE Software Check of luox.app

The University of Oxford has developed an open-access software platform known as luox, which incorporates elements of CIE publications for the calculation of certain quantities integrated from spectral data. Under the terms of a licence agreement between the University of Oxford and the CIE, the CIE has agreed to endorse the software following a black-box validation of the software. This is the report of that validation exercise, based on the work of an ad hoc task group of the CIE Board of Administration. The task group selected 43 spectrafrom various sources, 19 being spectra with 5 nm intervals and 24 being spectra with 1 nm intervals, and calculated luminance (illuminance), a-opic radiances (a-opic irradiances), a-opic equivalent daylight luminances (a-opic equivalent daylight illuminances), a-opic efficacies of luminous radiation, and chromaticity coordinates using both luox and a variety of other available reference calculation tools, both public and private. Tolerance intervals were established for each quantity, and the deviation between the test values from luox and thereference values were calculated for each spectrum. The results for all of these evaluations showed consistency between the test values and the reference values. Based on these results, the CIE approves the following statement concerning the luox software, as per the aforementioned licence agreement:“This software incorporates methods, formulae, spectral function calculations and spectra from the International Commission on Illumination (CIE). The CIE endorses this software having made a black-box evaluation of the software as of Feb. 11, 2021, finding that the software performs satisfactorily. This software is not a replacement for the CIE publications and works from which it is derived. The user is advised to consult the original publications and works for proper understanding of and calculation of the result of this software.

Founding quantum theory on the basis of consciousness

In the present work, quantum theory is founded on the framework of consciousness, in contrast to earlier suggestions that consciousness might be understood starting from quantum theory. The notion of streams of consciousness, usually restricted to conscious beings, is extended to the notion of a Universal/Global stream of conscious flow of ordered events. The streams of conscious events which we experience constitute sub-streams of the Universal stream. Our postulated ontological character of consciousness also consists of an operator which acts on a state of potential consciousness to create or modify the likelihoods for later events to occur and become part of the Universal conscious flow. A generalized process of measurement-perception is introduced, where the operation of consciousness brings into existence, from a state of potentiality, the event in consciousness. This is mathematically represented by (a) an operator acting on the state of potential-consciousness before an actual event arises in consciousness and (b) the reflecting of the result of this operation back onto the state of potential-consciousness for comparison in order for the event to arise in consciousness. Beginning from our postulated ontology that consciousness is primary and from the most elementary conscious contents, such as perception of periodic change and motion, quantum theory follows naturally as the description of the conscious experience.Comment: 41 pages, 3 figures. To be published in Foundations of Physics, Vol 36 (6) (June 2006), published online at http://dx.doi.org/10.1007/s10701-006-9049-

Optimizing land management strategies for maximum improvements in lake dissolved oxygen concentrations

Eutrophication and anoxia are unresolved issues in many large waterbodies. Globally, management success has been inconsistent, highlighting the need to identify approaches which reliably improve water quality. We used a process-based model chain to quantify effectiveness of terrestrial nutrient control measures on in-lake nitrogen, phosphorus, chlorophyll and dissolved oxygen (DO) concentrations in Lake Simcoe, Canada. Across a baseline period of 2010–2016 hydrochemical outputs from catchment models INCA-N and INCA-P were used to drive the lake model PROTECH, which simulated water quality in the three main basins of the lake. Five terrestrial nutrient control strategies were evaluated. Effectiveness differed between catchments, and water quality responses to nutrient load reductions varied between deep and shallow lake basins. Nutrient load reductions were a significant driver of increased DO concentrations, however strategies which reduced tributary inflow had a greater impact on lake restoration, associated with changes in water temperature and chemistry. Importantly, when multiple strategies were implemented simultaneously, resultant large flow reductions induced warming throughout the water column. Negative impacts of lake warming on DO overwhelmed the positive effects of nutrient reduction, and limited the effectiveness of lake restoration strategies. This study indicates that rates of lake recovery may be accelerated through a coordinated management approach, which considers strategy interactions, and the potential for temperature change-induced physical and biological feedbacks. Identified impacts of flow and temperature on rates of lake recovery have implications for management sustainability under a changing climate

Instability and freezing in a solidifying melt conduit

Author Posting. © The Author(s), 2010. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Physica D: Nonlinear Phenomena 240 (2011): 131-139, doi:10.1016/j.physd.2010.10.009.Previous works have shown that when liquid flows in a pipe whose boundary temperature is below freezing, a tubular drainage conduit forms surrounded by solidified material that freezes shut under the appropriate combination of forcing conditions. We conduct laboratory experiments with wax in which the tube freezes shut below a certain value of flux from a pump. As the flux is gradually decreased to this value, the total pressure drop across the length of the tube first decreases to a minimum value and then rises before freezing. Previous theoretical models of a tube driven by a constant pressure drop suggest that once the pressure minimum is reached, the states for a lower flux should be unstable and the tube should therefore freeze up. In our experiments, flux and pressure drop were coupled, and this motivates us to extend the theory for low-Reynolds number flow through a tube with solidification to incorporate a simple pressure drop-flux relationship. Our model predicts a steady-state relationship between flux and pressure drop that has a minimum of the pressure as the flux is varied. The stability properties of these steady states depend on the boundary conditions: for a fixed flux, they are all stable, whereas for fixed pressure drop, only those with a flux larger than that at the pressure drop minimum are stable. For a mixed pressure-flux condition, the stability threshold of the steady states lies between these two end members. This provides a possible mechanism for the experimental observations.Support was received from the Geophysical Fluid Dynamics Program, which is supported by the Ocean Sciences Division of the National Science Foundation under Grant OCE-0325296, and from the Oceanography Section of the Office of Naval Research under Grant N00014-07-1-0776. The laboratory experiments were supported by the Deep Ocean Exploration Institute of W.H.O.I

Tibiofemoral Contact Forces in the Anterior Cruciate Ligament-Reconstructed Knee.

PURPOSE: To investigate differences in ACL reconstructed (ACLR) and healthy individuals in terms of the magnitude of the tibiofemoral contact forces, as well as the relative muscle and external load contributions to those contact forces, during walking, running and sidestepping gait tasks. METHODS: A computational electromyography-driven neuromusculoskeletal model was used to estimate the muscle and tibiofemoral contact forces in those with combined semitendinosus and gracilis tendon autograft ACLR (n=104, 29.7±6.5 years, 78.1±14.4 kg) and healthy controls (n=60, 27.5±5.4 years, 67.8±14.0 kg) during walking (1.4±0.2 ms), running (4.5±0.5 ms) and sidestepping (3.7±0.6 ms). Within the computational model, the semitendinosus of ACLR participants was adjusted to account for literature reported strength deficits and morphological changes subsequent to autograft harvesting. RESULTS: ACLRs had smaller maximum total and medial tibiofemoral contact forces (~80% of control values, scaled to bodyweight) during the different gait tasks. Compared to controls, ACLRs were found to have a smaller maximum knee flexion moment, which explained the smaller tibiofemoral contact forces. Similarly, compared to controls, ACLRs had both a smaller maximum knee flexion angle and knee flexion excursion during running and sidestepping, which may have concentrated the articular contact forces to smaller areas within the tibiofemoral joint. Mean relative muscle and external load contributions to the tibiofemoral contact forces were not significantly different between ACLRs and controls. CONCLUSION: ACLRs had lower bodyweight-scaled tibiofemoral contact forces during walking, running and sidestepping, likely due to lower knee flexion moments and straighter knee during the different gait tasks. The relative contributions of muscles and external loads to the contact forces were equivalent between groups

Мультипарадигмальний підхід до аналізу феномену нігілізму

У статті розглянуто нігілізм як неоднозначне й поліморфне поняття. Досліджено різні підходи до тлумачення та розв’язання питань, пов’язаних із нігілізмом. Розкрито людиномірність нігілізму в контексті відстеження варіативного смислового навантаження феномену. Встановлено, що нігілізм потрібно позиціонувати як спосіб пробудження людського духу, заперечення деструктивного конформізму й відсутності опору (пасивний песимізм).В статье рассмотрен нигилизм как неоднозначное и полиморфное понятие. Исследованы различные подходы к толкованию и решению вопросов, связанных с нигилизмом. Раскрыта человекомерность нигилизма в контексте отслеживания вариативной смысловой нагрузки феномена. Установлено, что нигилизм нужно позиционировать как способ пробуждения человеческого духа, отрицание деструктивного конформизма и отсутствия сопротивления (пассивный пессимизм).Nihilism is considered as ambiguous and polymorphic concept. Different approaches to the interpretation and solution of issues associated with nihilism are investigated. Human measurement of nihilism in the context of tracking meaning of varied semantic capacity of the phenomenon is revealed. It is determined that nihilism must be positioned as a way of awakening of the human spirit, denial of destructive conformism and absence of resistance (passive pessimism)

A Full PFPF Shell Model Study of a~=~48 Nuclei

Exact diagonalizations with a minimally modified realistic force lead to detailed agreement with measured level schemes and electromagnetic transitions in $^{48}$Ca, $^{48}$Sc, $^{48}$Ti, $^{48}$V, $^{48}$Cr and $^{48}$Mn. Gamow-Teller strength functions are systematically calculated and reproduce the data to within the standard quenching factor. Their fine structure indicates that fragmentation makes much strength unobservable. As a by-product, the calculations suggest a microscopic description of the onset of rotational motion. The spectroscopic quality of the results provides strong arguments in favour of the general validity of monopole corrected realistic forces, which is discussed.Comment: 30 pages, LaTeX with epsf.sty, 14 Postscript figures included and compressed using uufiles. Completely new version of previous preprint nucl-th/9307001. FTUAM-93/01, CRN/PT 93-3

Examining the Context of Strategy Instruction

The goal of literacy instruction is to teach reading and writing as tools to facilitate thinking and reasoning in a broad array of literacy events. An important difference in the disposition of children to participate in literacy experiences is the extent to which they engage in intentional self-regulated learning. The contexts attending six traditional models of strategy instruction are examined. An exploratory study, conducted with heterogeneous third graders, is reported, examining the implementation and outcomes of three models of strategy instruction—Direct Instruction, Reciprocal Teaching, and Collaborative Problem Solving—which manipulated teacher and student control of activity, as well as the instructional context.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69008/2/10.1177_074193259101200306.pd