895 research outputs found
Risk Management, Capital Structure and Lending at Banks
We test how active management of bank credit risk exposure through the loan sales market affects capital structure, lending, profits, and risk. We find that banks that rebalance their C&I loan portfolio exposures by both buying and selling loans – that is, banks that use the loan sales market for risk management purposes rather than to alter their holdings of loans -- hold less capital than other banks; they also make more risky loans (loans to businesses) as a percentage of total assets than other banks. Holding size, leverage and lending activities constant, banks active in the loan sales market have lower risk and higher profits than other banks. We conclude that increasingly sophisticated risk management practices in banking are likely to improve the availability of bank credit but not to reduce bank risk.
Analysis and preliminary design of optical sensors for propulsion control
A fiber-optic sensor concept screening study was performed. Twenty sensor subsystems were identified and evaluated. Two concepts selected for further study were the Fabry-Perot fiber-optic temperature sensor and the pulse-width-modulated phosphorescent temperature sensor. Various designs suitable for a Fabry-Perot temperature sensor to be used as a remote fiber-optic transducer were investigated. As a result, a particular design was selected and constructed. Tests on this device show that spectral peaks are produced from visible white light, and the change in wavelength of the spectral peaks produced by a change in temperature is consistent with theory and is 36 nm/C for the first order peak. A literature search to determine a suitable phosphor for implementing the pulse-width-modulated fiber optic temperature sensor was conducted. This search indicated that such a device could be made to function for temperatures up to approximately 200 C. Materials like ZnCdS and ZnSe activated with copper will be particularly applicable to temperature sensing in the cryogenic to room temperature region. While this sensing concept is probably not applicable to jet engines, the simplicity and potential reliability make the concept highly desirable for other applications
Models and frameworks for assessing the value of disaster research
Funders, governments, stakeholders and end-users expect to see tangible evidence that an investment in research is a worthy use of resources. Research has impact if it makes a demonstrable contribution to the economy, society, culture, public policy, health, the environment, or quality of life, beyond academia.
This paper reviews frameworks that assess the impact of research and considers their usefulness in the conceptualisation and measurement of research impact in the disaster domain. Frameworks demonstrate impact through attribution, measurement and quantification of academic, social, and economic impacts in the short, medium and long term. While there is no specific framework in the hazard domain, adaptation of the “pathways to research impact” tool created by Cruz Rivera et al. (2017) provides a well-considered basis for assessing disaster research impact
SPARC CCMVal (2010), SPARC Report on the Evaluation of Chemistry-Climate Models: Chapter 5: Transport
Sensitivity of stratospheric inorganic chlorine to differences in transport
International audienceCorrectly modeling stratospheric inorganic chlorine (Cly) is crucial for modeling the past and future evolution of stratospheric ozone. However, comparisons of the chemistry climate models used in the latest international assessment of stratospheric ozone depletion have shown large differences in the modeled Cly, with these differences explaining many of the differences in the simulated evolution of ozone over the next century. Here in, we examine the role of transport in determining the simulated Cly using three simulations from the same off-line chemical transport model that have the same lower tropospheric boundary conditions and the same chemical solver, but differing resolution and/or meteorological fields. These simulations show that transport plays a key role in determining the Cly distribution, and that Cly depends on both the time scales and pathways of transport. The time air spends in the stratosphere (e.g., the mean age) is an important transport factor determining stratospheric Cly, but the relationship between mean age and Cly is not simple. Lower stratospheric Cly depends on the fraction of air that has been in the upper stratosphere, and transport differences between models having the same mean age can result in differences in the fraction of organic chlorine converted into Cly. Differences in transport pathways result in differences in vertical profiles of CFCs, and comparisons of observed and modeled CFC profiles provide a stringent test of transport pathways in models
Method and apparatus for a Fabry-Perot multiple beam fringe sensor
A method and, in one embodiment of the invention, the resulting apparatus for implementing a unique multiple beam fringe sensor that is adapted to be interfaced with a low cost, compact fiber optic transmission system in order to provide an accurate digital representation of a physical parameter (e.g. temperature) of a remote sample. The sensor is fabricated so as to include a Fabry-Perot gap formed between the ends of two mated optical fibers. By examining the optical characteristics of light that is transmitted through the Fabry-Perot sensor gap, an indication of gap width can be ascertained. Accordingly, a change in Fabry-Perot sensor gap width is related to a change in the particular physical parameter to be measured. In another embodiment of the invention, a second unique multiple beam fringe sensor having a Fabry-Perot gap is disclosed that is also adapted to provide an accurate digital representation of a physical parameter (e.g. temperature) of a remote sample. The sensor may be fabricated in two segments. A fiber containing segment includes each of a driving optical fiber for supplying incident light signals to the Fabry-Perot gap and a sensing optical fiber for receiving output light signals that have been transmitted twice through the Fabry-Perot gap, the optical characteristics of which output signals provide an indication of the parameter to be sensed. A transducer segment includes the Fabry-Perot gap formed therein and means responsive to the physical parameter for changing the width of the Fabry-Perot gap and, accordingly, the optical characteristics of the light signals passing therethrough
Method and apparatus for holographic processing
A method and apparatus for holographically processing optical signals in a fiber-optic sensor system. In the present invention, holographic processors are utilized in various combinations with light sources, fiber-optic transmission means, sensors and detectors to provide low cost, compact, sensitive and accurate sensor systems. By means of the holographic processors of the present invention, the aforementioned sensor systems are used to monitor such physical parameters as temperature, pressure, flow-rate, and the like, and to provide output signal indications thereof that are compatible with digital receiving stations and immune to electro-magnetic interference, hazardous atmosphere, and the inimical effects of inadvertent intensity variation due to equipment vibration and the like. In one typical embodiment, a pair of holographic processors are employed in a color multiplex-demultiplex sensor system in which a first holographic processor is employed to color multiplex a sensor signal and a second holographic processor is employed to decode the color-multiplexed signal into a binary pattern that is then transmitted onto a set of photodetectors. In each of the embodiments of the invention disclosed, a unique geometrical orientation of a hologram is utilized to minimize spurious signal interference that would otherwise hamper or totally preclude the holographic processing
Method and apparatus for a Fabry-Perot multiple beam fringe sensor
A method and the resulting apparatus for implementing a unique multiple beam fringe sensor that is adapted to be interfaced with a low cost, compact fiber optic transmission system in order to provide an accurate digital representation of a physical parameter (e.g. temperature) of a remote sample. The sensor is fabricated so as to include a Fabry-Perot gap formed between the ends of two mated optical fibers. By examining the optical characteristics of light that is transmitted through the Fabry-Perot sensor gap, an indication of gap width can be ascertained. Accordingly, a change in Fabry-Perot sensor gap width is related to a change in the particular physical parameter to be measured
Transport and modeling of stratospheric inorganic chlorine
International audienceCorrectly modeling stratospheric inorganic chlorine (Cly) is crucial for modeling the past and future evolution of stratospheric ozone. However, comparisons of the chemistry climate models used in the latest international assessment of stratospheric ozone depletion have shown large differences in the modeled Cly, with these differences explaining differences in the simulated evolution of ozone over the next century. Here in, we examine the role of transport in determining the simulated Cly using three simulations from the same off-line chemical transport model that have the same lower tropospheric boundary conditions and the same chemical solver, but differing resolution and/or meteorological fields. These simulations show that transport plays a key role in determining the Cly distribution, and that Cly depends on both the time scales and pathways of transport. The time air spends in the stratosphere (e.g., the mean age) is an important transport factor determining stratospheric Cly, but the relationship between mean age and Cly is not simple. Lower stratospheric Cly depends on the fraction of air that has been in the upper stratosphere, and transport differences between models having the same mean age can result in differences in the fraction of organic chlorine converted into Cly. Differences in transport pathways result in differences in vertical profiles of CFCs, and comparisons of observed and modeled CFC profiles provides a stringent test of transport pathways in models
Optical temperature sensor utilizing birefringent crystals
A temperature sensor comprising an optical transducer member having an array of birefringent crystals. The length and, accordingly, the sensitivity to temperature change of successive birefringent crystals varies according to a particular relationship. The transducer is interconnected with a fiber optic transmission and detecting system. Respective optical output signals that are transmitted from the birefringent crystals via the fiber optic transmission system are detected and decoded so as to correspond to digits of a numbering system, whereby an accurate digital representation of temperature can ultimately be provided
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