2,274 research outputs found
Utilización de antropometrÃa en el diseño para mejorar el desempeño de la tripulación
Today’s naval ship or craft designer routinely uses the principles of human factors (ergonomics) as a way to help enhance crew performance. But even though many aspects of human factors are well known, certain important categories often remain underutilized. One of these categories is anthropometrics, the study of human body dimensions and capabilities. Anthropometrics analyzes age, gender, and other data within populations of people, such as the general population of a nation or the special population of that nation’s active duty naval personnel. For the naval designer, anthropometrics helps to ensure adequate ergonomic design for the population from which the crew is drawn. The naval designer can address in a quantifiable manner issues such as lines of sight, console height and valve handle accessibility. When anthropometric principles are thus applied, the ship better fits the capabilities and limitations of the crew, resulting in enhanced crew performance.El diseñador actual de buques navales o embarcaciones rutinariamente utiliza los principios de los factores humanos (ergonomÃa) como una manera para mejorar el desempeño de la tripulación. Pero, aunque muchos aspectos de los factores humanos son bien conocidos, ciertas categorÃas importantes a menudo permanecen subutilizadas. Una de estas categorÃas es la antropometrÃa, el estudio de las dimensiones y capacidades del cuerpo humano. La antropometrÃa analiza la edad, sexo y otros datos dentro de poblaciones de personas, como la población general de una nación o la población especial del personal naval en servicio activo de esa nación. Para el diseñador naval, la antropometrÃa ayuda a asegurar el diseño ergonómico adecuado para la población de donde se obtiene la tripulación. El diseñador naval puede abordar confiablemente asuntos como linea de visión, altura de consola y accesibilidad de agarraderas de válvulas. Cuando los principios de la antropometrÃa se aplican de esta manera, el buque encaja mejor con las capacidades y limitaciones de la tripulación, con el resultado del desempeño mejorado de la tripulación
The selective oxidation of methane to ethane and ethylene over doped and un-doped rare earth oxides
A comparison has been made of the behaviour in the oxidative coupling of methane of the oxides of Sm, Dy, Gd, La and Tb with that of a Li/MgO material. All but the Tb4O7 (which gave total oxidation) were found to give higher yields than the Li/MgO material at temperatures up to approaching 750°C but the Li/MgO system gave better results at higher temperatures. The cubic structure of Sm2O3 was found to be responsible for its good performance while the monoclinic structure was relatively inactive and unselective. The addition of Na or Ca to cubic Sm2O3 gives a higher optimum C2 yield than that of unpromoted Sm2O3. Sm2O3 and Ca/Sm2O3 catalysts are more stable than Li/MgO, Li/Sm2O3 or Na/Sm2O3. The addition of Li or Na to Sm2O3 causes the structure to change from cubic to monoclinic; the deactivation of the Na/Sm2O3 catalysts is caused by a loss of Na coupled with the formation of the monoclinic form of Sm2O3
Development of MY FRAM matrix to assess food safety risks in horticultural crops
A farm food safety risk assessment matrix (MY FRAM) was developed for horticultural farms. The tool enables farmers to carry out self risk assessments on the potential of food safety risks on the farm from site selection to post-harvest handling. MY FRAM was developed on Microsoft ASP. NET C# 4.5 with logical functions and utilised a semi-quantitative risk assessment approach (risk ranking of 1 – 9) for farmers. MY FRAM is an illustrative risk ranking tool to allow farmers to quickly identify potential food safety risks and risk summary and corrective actions are suggested to farms on how to reduce the risks. The tool can also be utilised as a training tool for farm workers to understand the importance of food safety at the farm level
Integrable Deformations of Strings in Flux Backgrounds
We study d=2 0A string theory perturbed by tachyon momentum modes in
backgrounds with non-trivial tachyon condensate and Ramond-Ramond (RR) flux. In
the matrix model description, we uncover a complexified Toda lattice hierarchy
constrained by a pair of novel holomorphic string equations. We solve these
constraints in the classical limit for general RR flux and tachyon condensate.
Due to the non-holomorphic nature of the tachyon perturbations, the
transcendental equations which we derive for the string susceptibility are
manifestly non-holomorphic. We explore the phase structure and critical
behavior of the theory.Comment: 39 pages, 4 figure
Trends in sexually transmitted infections in general practice 1990-2000: population based study using data from the UK general practice research database
Objective: To describe the contribution of primary care to the
diagnosis and management of sexually transmitted infections in
the United Kingdom, 1990-2000, in the context of increasing
incidence of infections in genitourinary medicine clinics.
Design: Population based study.
Setting: UK primary care.
Participants: Patients registered in the UK general practice
research database.
Main outcome measures: Incidence of diagnosed sexually
transmitted infections in primary care and estimation of the
proportion of major such infections diagnosed in primary care.
Results: An estimated 23.0% of chlamydia cases in women but
only 5.3% in men were diagnosed and treated in primary care
during 1998-2000, along with 49.2% cases of non-specific
urethritis and urethral discharge in men and 5.7% cases of
gonorrhoea in women and 2.9% in men. Rates of diagnosis in
primary care rose substantially in the late 1990s.
Conclusions: A substantial and increasing number of sexually
transmitted infections are diagnosed and treated in primary
care in the United Kingdom, with sex ratios differing from
those in genitourinary medicine clinics. Large numbers of men
are treated in primary care for presumptive sexually
transmitted infections
Driver reaction to navigation instructions incorporating good and poor landmarks
The study consisted of a road-based trial involving 48 participants using a navigation system to complete a
complex urban route. The participants were divided into three matched groups experiencing one of the following landmark conditions: good, poor or no landmarks, incorporated in verbal instructions. A range of objective and
subjective measures were taken to assess driver performance with and attitudes to each of the landmark
categories. The aims were to:
• assess the impact on driver performance and attitudes of presenting navigation instructions which included
good, poor or no landmarks
• validate the REGIONAL model, which was developed to predict the navigational value of individual landmarks
• identify any other factors (e.g. driver or manoeuvre characteristics) that may affect the value of landmark
Integrating process design and control: An application of optimal control to chemical processes
In this paper, the optimal design of process systems generically used in chemical industries is studied. The closely coupled nature of optimal design specification of the equipment, the determination of the optimal process parameters in steady-state, moreover, some issues of the application of optimal control is shown. The solution of the overall optimization problem including (i) optimal design of the equipment and (ii) specification of its optimal control strategy can be found relying on two different design concepts, namely, on the conventionally used sequential or, on the newly emerged simultaneous design approaches. This paper gives the theoretical background of the ideas and presents a comparative summary of the approaches. The two approaches are contrasted to each other in which the effects of the interaction of optimal process design and optimal control is highlighted. A new simultaneous optimization procedure providing economic and operability benefits over the traditional stand-alone approach is proposed. The applicability of the idea is demonstrated by means of a design study carried out for optimal design of a coaxial heat exchanger and a reactive distillation column for the synthesis of ethyl tert butyl ether (ETBE), relying on the benefits of the utilization of optimal control
Measuring Black Hole Spin using X-ray Reflection Spectroscopy
I review the current status of X-ray reflection (a.k.a. broad iron line)
based black hole spin measurements. This is a powerful technique that allows us
to measure robust black hole spins across the mass range, from the stellar-mass
black holes in X-ray binaries to the supermassive black holes in active
galactic nuclei. After describing the basic assumptions of this approach, I lay
out the detailed methodology focusing on "best practices" that have been found
necessary to obtain robust results. Reflecting my own biases, this review is
slanted towards a discussion of supermassive black hole (SMBH) spin in active
galactic nuclei (AGN). Pulling together all of the available XMM-Newton and
Suzaku results from the literature that satisfy objective quality control
criteria, it is clear that a large fraction of SMBHs are rapidly-spinning,
although there are tentative hints of a more slowly spinning population at high
(M>5*10^7Msun) and low (M<2*10^6Msun) mass. I also engage in a brief review of
the spins of stellar-mass black holes in X-ray binaries. In general,
reflection-based and continuum-fitting based spin measures are in agreement,
although there remain two objects (GROJ1655-40 and 4U1543-475) for which that
is not true. I end this review by discussing the exciting frontier of
relativistic reverberation, particularly the discovery of broad iron line
reverberation in XMM-Newton data for the Seyfert galaxies NGC4151, NGC7314 and
MCG-5-23-16. As well as confirming the basic paradigm of relativistic disk
reflection, this detection of reverberation demonstrates that future large-area
X-ray observatories such as LOFT will make tremendous progress in studies of
strong gravity using relativistic reverberation in AGN.Comment: 19 pages. To appear in proceedings of the ISSI-Bern workshop on "The
Physics of Accretion onto Black Holes" (8-12 Oct 2012). Revised version adds
a missing source to Table 1 and Fig.6 (IRAS13224-3809) and corrects the
referencing of the discovery of soft lags in 1H0707-495 (which were in fact
first reported in Fabian et al. 2009
Lodged in the throat: Internal infinities and AdS/CFT
In the context of AdS3/CFT2, we address spacetimes with a certain sort of
internal infinity as typified by the extreme BTZ black hole. The internal
infinity is a null circle lying at the end of the black hole's infinite throat.
We argue that such spacetimes may be described by a product CFT of the form
CFT-L * CFT-R, where CFT-R is associated with the asymptotically AdS boundary
while CFT-L is associated with the null circle. Our particular calculations
analyze the CFT dual of the extreme BTZ black hole in a linear toy model of
AdS3/CFT2. Since the BTZ black hole is a quotient of AdS3, the dual CFT state
is a corresponding quotient of the CFT vacuum state. This state turns out to
live in the aforementioned product CFT. We discuss this result in the context
of general issues of AdS/CFT duality and entanglement entropy.Comment: 11 pages, 2 figures; v2 - some typos corrected, minor revision
- …