2,616 research outputs found
Study of cryogenic propellant systems for loading the space shuttle
Computer programs were written to model the liquid oxygen loading system for the space shuttle. The programs allow selection of input data through graphic displays which schematically depict the part of the system being modeled. The computed output is also displayed in the form of graphs and printed messages. Any one of six computation options may be selected. The first four of these pertain to thermal stresses, pressure surges, cooldown times, flow rates and pressures during cooldown. Options five and six deal with possible water hammer effects due to closing of valves, steady flow and transient response to changes in operating conditions after cooldown. Procedures are given for operation of the graphic display unit and minicomputer
Cooldown time for simple cryogenic pipelines
Cooldown time for simple cryogenic pipeline
The Truth in Compatibilism and the truth of Libertarianism
The paper offers the outlines of a response to the often-made suggestion is that it is impossible to see how indeterminism could possibly provide us with anything that we might want in the way of freedom, anything that could really amount to control, as opposed merely to an openness in the flow of reality that would constitute merely the injection of chance, or randomness, into the unfolding of the processes which underlie our activity. It is suggested that the best first move for the libertarian is to make a number of important concessions to the compatibilist. It should be conceded, in particular, that certain sorts of alternative possibilities are neither truly available to real, worldly agents, nor required in order that those agents should act freely; and it should be admitted also that it is the compatibilist who tends to give the most plausible sorts of analyses of many of the âcanâ and âcould haveâ statements which seem to need to be assertible of those agents we regard as free. But these concessions do not bring compatibilism itself in their wake. The most promising version of libertarianism, it is argued, should be based on the idea that agency itself (and not merely some special instances of it which we might designate with the honorific appellation âfreeâ) is inconsistent with determinism. This version of libertarianism, it is claimed, can avoid the objection that indeterminism is as difficult to square with true agential control as determinism can sometimes seem to be
Do actions occur inside the body?
The paper offers a critical examination of Jennifer Hornsby's view that actions are internal to the body. It focuses on three of Hornsby's central claims: (P) many actions are bodily movements (in a special sense of the word âmovementâ) (Q) all actions are tryings; and (R) all actions occur inside the body. It is argued, contra Hornsby, that we may accept (P) and (Q) without accepting also the implausible (R). Two arguments are first offered in favour of the thesis (Contrary-R): that no actions occur inside the body. Three of Hornsby's arguments in favour of R are then examined. It is argued that we need to make a distinction between the causes and the causings of bodily movements (in the ordinary sense of the word âmovementâ) and that actions ought to be identified with the latter rather than the former. This distinction is then used to show how Hornsby's arguments for (R) may be resisted
PinR mediates the generation of reversible population diversity in Streptococcus zooepidemicus
Opportunistic pathogens must adapt to and survive in a wide range of complex ecosystems. Streptococcus zooepidemicus is an opportunistic pathogen of horses and many other animals, including humans. The assembly of different surface architecture phenotypes from one genotype is likely to be crucial to the successful exploitation of such an opportunistic lifestyle. Construction of a series of mutants revealed that a serine recombinase, PinR, inverts 114 bp of the promoter of SZO_08560, which is bordered by GTAGACTTTA and TAAAGTCTAC inverted repeats. Inversion acts as a switch, controlling the transcription of this sortase-processed protein, which may enhance the attachment of S. zooepidemicus to equine trachea. The genome of a recently sequenced strain of S. zooepidemicus, 2329 (Sz2329), was found to contain a disruptive internal inversion of 7 kb of the FimIV pilus locus, which is bordered by TAGAAA and TTTCTA inverted repeats. This strain lacks pinR and this inversion may have become irreversible following the loss of this recombinase. Active inversion of FimIV was detected in three strains of S. zooepidemicus, 1770 (Sz1770), B260863 (SzB260863) and H050840501 (SzH050840501), all of which encoded pinR. A deletion mutant of Sz1770 that lacked pinR was no longer capable of inverting its internal region of FimIV. The data highlight redundancy in the PinR sequence recognition motif around a short TAGA consensus and suggest that PinR can reversibly influence the wider surface architecture of S. zooepidemicus, providing this organism with a bet-hedging solution to survival in fluctuating environments
Personal and sub-personal: a defence of Dennett's early distinction
Since 1969, when Dennett introduced a distinction between personal and subâpersonal levels of explanation, many philosophers have used âsubâpersonalâ very loosely, and Dennett himself has abandoned a view of the personal level as genuinely autonomous. I recommend a position in which Dennett's original distinction is crucial, by arguing that the phenomenon called mental causation is on view only at the properly personal level. If one retains the commitââ ments incurred by Dennett's early distinction, then one has a satisfactory antiâphysicalistic, antiâdualist philosophy of mind. It neither interferes with the projects of subâpersonal psychology, nor encourages ; instrumentalism at the personal level.
People lose sight of Dennettâs personal/sub-personal distinction because they free it from its philosophical moorings. A distinction that serves a philosophical purpose is typically rooted in doctrine; it cannot be lifted out of context and continue to do its work. So I shall start from Dennettâs distinction as I read it in its original context. And when I speak of âthe distinctionâ, I mean to point not only towards the terms that Dennett first used to define it but also towards the philosophical setting within which its work was cut out
The Ontology of Intentional Agency in Light of Neurobiological Determinism: Philosophy Meets Folk Psychology
The moot point of the Western philosophical rhetoric about free will
consists in examining whether the claim of authorship to intentional, deliberative
actions fits into or is undermined by a one-way causal framework of determinism.
Philosophers who think that reconciliation between the two is possible are known as
metaphysical compatibilists. However, there are philosophers populating the other
end of the spectrum, known as the metaphysical libertarians, who maintain that claim
to intentional agency cannot be sustained unless it is assumed that indeterministic
causal processes pervade the action-implementation apparatus employed by the agent.
The metaphysical libertarians differ among themselves on the question of whether the
indeterministic causal relation exists between the series of intentional states and
processes, both conscious and unconscious, and the action, making claim for what has
come to be known as the event-causal view, or between the agent and the action,
arguing that a sort of agent causation is at work. In this paper, I have tried to propose
that certain features of both event-causal and agent-causal libertarian views need to be
combined in order to provide a more defendable compatibilist account accommodating
deliberative actions with deterministic causation. The ââagent-executed-eventcausal
libertarianismââ, the account of agency I have tried to develop here, integrates
certain plausible features of the two competing accounts of libertarianism turning
them into a consistent whole. I hope to show in the process that the integration of these
two variants of libertarianism does not challenge what some accounts of metaphysical
compatibilism proposeâthat there exists a broader deterministic relation between the
web of mental and extra-mental components constituting the agentâs dispositional
systemâthe agentâs beliefs, desires, short-term and long-term goals based on them,
the acquired social, cultural and religious beliefs, the general and immediate and
situational environment in which the agent is placed, etc. on the one hand and the
decisions she makes over her lifetime on the basis of these factors. While in the
ââIntroductionââ the philosophically assumed anomaly between deterministic causation
and the intentional act of deciding has been briefly surveyed, the second section is
devoted to the task of bridging the gap between compatibilism and libertarianism. The
next section of the paper turns to an analysis of folk-psychological concepts and
intuitions about the effects of neurochemical processes and prior mental events on the
freedom of making choices. How philosophical insights can be beneficially informed
by taking into consideration folk-psychological intuitions has also been discussed,
thus setting up the background for such analysis. It has been suggested in the end that
support for the proposed theory of intentional agency can be found in the folk-psychological intuitions, when they are taken in the right perspective
Cooldown of Cryogenic Transfer Lines an Experimental Report
Pressure, temperature, and flow during cooldown of cryogenic transfer line
(G)hosting television: Ghostwatch and its medium
This articleâs subject is Ghostwatch (BBC, 1992), a drama broadcast on Halloween night of 1992 which adopted the rhetoric of live non-fiction programming, and attracted controversy and ultimately censure from the Broadcasting Standards Council. In what follows, we argue that Ghostwatch must be understood as a televisually-specific artwork and artefact. We discuss the programmeâs ludic relationship with some key features of television during what Ellis (2000) has termed its era of âavailabilityâ, principally liveness, mass simultaneous viewing, and the flow of the television super-text. We trace the programmeâs television-specific historicity whilst acknowledging its allusions and debts to other media (most notably film and radio). We explore the sophisticated ways in which Ghostwatchâs visual grammar and vocabulary and deployment of âbroadcast talkâ (Scannell 1991) variously ape, comment upon and subvert the rhetoric of factual programming, and the ends to which these strategies are put. We hope that these arguments collectively demonstrate the aesthetic and historical significance of Ghostwatch and identify its relationship to its medium and that mediumâs history. We offer the programme as an historically-reflexive artefact, and as an exemplary instance of the work of art in televisionâs age of broadcasting, liveness and co-presence
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