912 research outputs found
Comparing the Online Learning Capabilities of Gaussian ARTMAP and Fuzzy ARTMAP for Building Energy Management Systems
Recently, there has been a growing interest in the application of Fuzzy ARTMAP for use in building energy management systems or EMS. However, a number of papers have indicated that there are important weaknesses to the Fuzzy ARTMAP approach, such as sensitivity to noisy data and category proliferation. Gaussian ARTMAP was developed to help overcome these weaknesses, raising the question of whether Gaussian ARTMAP could be a more effective approach for building energy management systems? This paper aims to answer this question. In particular, our results show that Gaussian ARTMAP not only has the capability to address the weaknesses of Fuzzy ARTMAP but, by doing this, provides better and more efficient EMS controls with online learning capabilities
The Implementation and Operation of Three School-Based Health Centers in New Jersey
There is a construct of causation between common health issues affecting children and the corollary effects on a student’s ability and motivation to learn, including impaired sensory perceptions, cognition, connectedness and engagement with school, absenteeism, and dropping out (Basch, 2011b). What is more, causal connections have been found between a students’ health, their socio-economic status (SES), and the achievement gap that exists in education between students with a low-SES and others (Basch, 2011a). To address deficiencies in health care, some school districts have begun providing medical and mental healthcare in school buildings by opening school-based health centers (SBHC; Bains & Diallo, 2015; Guo et al., 2010; Koenig et al., 2016; Larson et al., 2017; School-Based Health Alliance, 2013).
This study sought to examine the implementation and operation of SBHCs specifically in New Jersey (NJ) public schools as data showed that though NJ had a large number of lower SES students there was a paucity of healthcare resources for them (Hing, Decker, & Jamoon, 2015). In fact, based on the last SBHC Census, NJ only had thirty-five centers whereas surrounding states had triple and quadruple that number (School-Based Health Alliance, 2013). There were three methods of center implementation found, which included school operated centers, collaboration centers, and Federally Qualified Health Centers (FQHC). Purposeful sampling was used to generate a sample of each method of implementation to study one of each. A qualitative bounded case study was utilized to collect, organize, and report information from the centers on their operations staffing, financial, policy, and monitoring.
The results of the study showed emerging themes important for school administrators to become cognizant of the method of center implementation that a school district chooses, including collaboration with the local medical community, use of mid-level practitioners, personnel costs as a major expenditure of the center, school nurses as a main referral source of students to the center, the understanding that the SBHC is not a replacement for the school nurse’s office, and emphasis on referrals and connections to outside providers. Within the literature, the researcher noted that SBHCs were monitored for efficacy based on a number of measures, including school connectedness, student achievement, student attendance, and educational attainment. The centers that were part of this study, while they were concerned with their impact on achievement and attainment, by and large viewed the SBHC as serving a public health benefit (Barnett & Allison, 2012) and enhancing a student’s connection with the school (Stone et al., 2013; Strolin-Goltzman, 2010, 2014)
Energy Network Communications and Expandable Control Mechanisms
A modular, expandable network requiring little or no calibration is something that is well sought after and would offer great benefits when used for distributed energy generation. Intelligent and adaptive control of such a network offers stability of supply from intermittent sources which, to date, has been hard to achieve.
Key to the effective use of such control systems is communications, specifically the exchange of commands and status information between the control systems and the attached devices. Power-line communications has been used in various applications for years and would offer a good mechanism for interconnecting devices on a power grid without the expense of laying new cabling.
By using clusters of devices managed by an IEMS (Intelligent Energy Management System) in a branching network fashion (not unlike the grid itself) it would be possible to manage large numbers of devices and high speed with relatively low bandwidth usage increasing the usable range of transmission. Implications of this include improving network efficiency through managed power distribution and increased security of supply
Computational modelling of structural integrity following mass loss in polymeric charred cellular solids
A novel computational technique is presented for embedding mass-loss due to burning into the ANSYS finite element modelling code. The approaches employ a range of computational modelling methods in order to provide more complete theoretical treatment of thermoelasticity absent from the literature for over six decades. Techniques are employed to evaluate structural integrity (namely, elastic moduli, Poisson’s ratios, and compressive brittle strength) of honeycomb systems known to approximate three-dimensional cellular chars. That is, reducing the mass of diagonal ribs and both diagonal-plus-vertical ribs simultaneously show rapid decreases in the structural integrity of both conventional and re-entrant (auxetic, i.e., possessing a negative Poisson’s ratio) honeycombs. On the other hand, reducing only the vertical ribs shows initially modest reductions in such properties, followed by catastrophic failure of the material system. Calculations of thermal stress distributions indicate that in all cases the total stress is reduced in re-entrant (auxetic) cellular solids. This indicates that conventional cellular solids are expected to fail before their auxetic counterparts.
Furthermore, both analytical and FE modelling predictions of the brittle crush strength of both auxetic and conventional cellular solids show a relationship with structural stiffness
A review of in-situ loading conditions for mathematical modelling of asymmetric wind turbine blades
This paper reviews generalized solutions to the classical beam moment equation for solving the deflexion and strain
fields of composite wind turbine blades. A generalized moment functional is presented to effectively model the moment
at any point on a blade/beam utilizing in-situ load cases. Models assume that the components are constructed from inplane
quasi-isotropic composite materials of an overall elastic modulus of 42 GPa. Exact solutions for the displacement
and strains for an adjusted aerofoil to that presented in the literature and compared with another defined by the
Joukowski transform. Models without stiffening ribs resulted in deflexions of the blades which exceeded the generally
acceptable design code criteria. Each of the models developed were rigorously validated via numerical (Runge-Kutta)
solutions of an identical differential equation used to derive the analytical models presented. The results obtained
from the robust design codes, written in the open source Computer Aided Software (CAS) Maxima, are shown to be
congruent with simulations using the ANSYS commercial finite element (FE) codes as well as experimental data. One
major implication of the theoretical treatment is that these solutions can now be used in design codes to maximize the
strength of analogues components, used in aerospace and most notably renewable energy sectors, while significantly
reducing their weight and hence cost. The most realistic in-situ loading conditions for a dynamic blade and stationary
blade are presented which are shown to be unique to the blade optimal tip speed ratio, blade dimensions and wind
speed
Computational actuator disc models for wind and tidal applications
This paper details a computational fluid dynamic (CFD) study of a constantly loaded actuator disc model featuring different boundary conditions; these boundary conditions were defined to represent a channel and a duct flow. The simulations were carried out using the commercially available CFD software ANSYS-CFX. The data produced were compared to the one-dimensional (1D)
momentum equation as well as previous numerical and experimental studies featuring porous discs in a channel flow. The actuator disc was modelled as a momentum loss using a resistance coefficient related to the thrust coefficient
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Improving Estimates of Seismic Source Parameters Using Surface-Wave Observations: Applications to Earthquakes and Underground Nuclear Explosions
We address questions related to the parameterization of two distinct types of seismic sources: earthquakes and underground nuclear explosions. For earthquakes, we focus on the improvement of location parameters, latitude and longitude, using relative measurements of spatial cluster of events. For underground nuclear explosions, we focus on the seismic source model, especially with regard to the generation of surface waves.
We develop a procedure to improve relative earthquake location estimates by fitting predicted differential travel times to those measured by cross-correlating Rayleigh- and Love-wave arrivals for multiple earthquakes recorded at common stations. Our procedure can be applied to populations of earthquakes with arbitrary source mechanisms because we mitigate the phase delay that results from surface-wave radiation patterns by making source corrections calculated from the source mechanism solutions published in the Global CMT Catalog. We demonstrate the effectiveness of this relocation procedure by first applying it to two suites of synthetic earthquakes. We then relocate real earthquakes in three separate regions: two ridge-transform systems and one subduction zone. In each scenario, relocated epicenters show a reduction in location uncertainty compared to initial single-event location estimates.
We apply the relocation procedure on a larger scale to the seismicity of the Eltanin Fault System which is comprised of three large transform faults: the Heezen transform, the Tharp transform, and the Hollister transform. We examine the localization of seismicity in each transform, the locations of earthquakes with atypical source mechanisms, and the spatial extent of seismic rupture and repeating earthquakes in each transform. We show that improved relative location estimates, aligned with bathymetry, greatly reduces the localization of seismicity on each of the three transforms. We also show how improved location estimates enhance the ability to use earthquake locations to address geophysical questions such as the presence of atypical earthquakes and the nature of seismic rupture along an oceanic transform fault.
We investigate the physical basis for the mb-MS discriminant, which relies on differences between amplitudes of body waves and surface waves. We analyze observations for 71 well-recorded underground nuclear tests that were conducted between 1977-1989 at the Balapan test site near Semipalatinsk, Kazakhstan in the former Soviet Union. We combine revised mb values and earlier long-period surface-wave results with a new source model, which allows the vertical and horizontal forces of the explosive source to be different. We introduce a scaling factor between vertical and horizontal forces in the explosion model, to reconcile differences between body wave and surface wave observations. We find that this parameter is well correlated with the scaled depth of burial for UNEs at this test site. We use the modified source model to estimate the scaled depth of burial for the 71 UNEs considered in this study
On the Deflexion of Anisotropic Structural Composite Aerodynamic Components
This paper presents closed form solutions to the classical beam elasticity differential equation in order to effectively model the displacement of standard aerodynamic geometries used throughout a number of industries. The models assume that the components are constructed from in-plane generally anisotropic (though shown to be quasi-isotropic) composite materials. Exact solutions for the displacement and strains for elliptical and FX66-S-196 and NACA 63-621 aerofoil approximations thin wall composite material shell structures, with and without a stiffening rib (shear-web), are presented for the first time. Each of the models developed is rigorously validated via numerical (Runge-Kutta) solutions of an identical differential equation used to derive the analytical models presented. The resulting calculated displacement and material strain fields are shown to be in excellent agreement with simulations using the ANSYS and CATIA commercial finite element (FE) codes as well as experimental data evident in the literature. One major implication of the theoretical treatment is that these solutions can now be used in design codes to limit the required displacement and strains in similar components used in the aerospace and most notably renewable energy sector
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