298 research outputs found
The development of a generic systems-level model for combustion-based domestic cogeneration
The provision of heat and power to dwellings from micro-cogeneration systems is gaining credence around the developed world as a possible means to reduce the significant carbon emissions associated with the domestic sector. However, achieving the optimum performance for these systems requires that building design practitioners are equipped with robust, integrated models, which will provide a realistic picture of the cogeneration performance in-situ. A long established and appropriate means to evaluate the energy performance of buildings and their energy systems is through the use of dynamic building simulation tools. However, until now, only a very limited number of micro-cogeneration device models have been available to the modelling community and generally these have not been appropriate for use within building simulation codes. This paper describes work undertaken within the International Energy Agency's Energy Conservation in Building and Community Systems Annex 42 to address this problem through the development of a generic, combustion based cogeneration device model that is suitable for integration within building simulation tools and can be used to simulate the variety of Internal Combustion Engine (ICE) and Stirling Engine (SE) cogeneration devices that are and will be available for integration into dwellings. The model is described in detail along with details of how it has been integrated into the ESP-r, Energy Plus and TRNSYS simulation platforms
Calibration and validation of a combustion-cogeneration
This paper describes the calibration and validation of a combustion cogeneration model for whole-building simulation. As part of IEA Annex 42, we proposed a combustion cogeneration model for studying residentialscale cogeneration systems based on both Stirling and internal combustion engines. We implemented this model independently in the EnergyPlus, ESP-r and TRNSYS building simulation programs, and undertook a comprehensive effort to validate the model's predictions. Using established comparative testing and empirical validation principles, we vetted the model's theoretical basis and its software implementations. The results demonstrate acceptable-to-excellent agreement, and suggest the calibrated model can be used with confidence
Principal Perceptions of Standards-Based Teacher Evaluation in West Virginia
Standards-based teacher evaluations have become the norm in many states due to an increased focus on student achievement and teacher effectiveness. These evaluations have become integral to the improvement of classroom instruction efforts and the planning of specific professional development for teachers. West Virginia deployed a new standards-based teacher evaluation system in 2014, using the West Virginia Professional Teaching Standards as a basis for measuring teacher performance and growth in certain areas. The new evaluation system also included teacher self-reflection and goal-setting portions. The purpose of this study was to assess the perceptions of school principals as to the effectiveness of the new standards-based West Virginia teacher evaluation system and its self-reflection and goal-setting portions. A researcher created survey was administered electronically through Survey Monkey to 695 West Virginia principals. The survey was completed by 281 principals for a response rate of 40%. The study’s findings suggested that while principals have an overall positive perception of the new system, they did not tend to regard it as extremely effective in enabling them to assess teacher performance. Ancillary findings suggested an ambivalence from principals regarding the degree to which the evaluation process and the evaluation instrument allowed them to effectively evaluate teachers. It is suggested that this study be replicated with the population expanded to include West Virginia teachers who have participated in the new evaluation system
Senior Recital: Brittany Griffith, mezzo-soprano
Brittany Griffith is pursuing a Music Minor. Brittany studies voice with Jana Young.https://digitalcommons.kennesaw.edu/musicprograms/1029/thumbnail.jp
Contrasting the capabilities of building energy performance simulation programs
For the past 50 years, a wide variety of building energy simulation programs have been developed, enhanced and are in use throughout the building energy community. This paper is an overview of a report, which provides up-to-date comparison of the features and capabilities of twenty major building energy simulation programs. The comparison is based on information provided by the program developers in the following categories: general modeling features; zone loads; building envelope and daylighting and solar; infiltration, ventilation and multizone airflow; renewable energy systems; electrical systems and equipment; HVAC systems; HVAC equipment; environmental emissions; economic evaluation; climate data availability, results reporting; validation; and user interface, links to other programs, and availability
Incorporating nodal and zonal room air models into building energy calculation procedures
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2002.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Includes bibliographical references (p. 105-111).by Brent T. Griffith.S.M
Ventricular Entrapment Due To Isolated Intraventricular Aspergillus Infection
Introduction: Intraventricular aspergillus infections are a rare manifestation of fungal infections of the central nervous system (CNS). Intraventricular aspergillus infections have most commonly been identified in immunocompromised patients. Spread to the central nervous system is thought to occur hematogenously (usually from pulmonary infection) or directly from the paranasal sinuses. Clinical diagnosis is difficult, as symptoms are nonspecific, but imaging can be used to create a more accurate differential. This case report describes the rare diagnosis of an intraventricular aspergillus infection in an immunocompromised patient presenting with ventricular entrapment and demonstrates the role of imaging in making the diagnosis.
Case Report: We present the case of a 59-year-old male with a history of renal transplant on immunosuppressive therapy, presenting with a two-week history of right-sided weakness and speech difficulty. Of note, patient was diagnosed with acute invasive pulmonary aspergillosis during a prior admission this year and had just completed a 12-week course of antifungal therapy. CT of the head at that time demonstrated only slight asymmetry of the ventricles without definite intracranial lesion. Initial non-contrast CT of the head demonstrated a complex cystic mass within the left lateral ventricle with asymmetric ventricular enlargement. CT of the head with contrast demonstrated a complex lesion within the left ventricle with peripheral enhancement and enlargement of the ventricle. MRI demonstrated a cystic lesion within the left lateral ventricle with a hyperintense FLAIR component anteriorly with restricted diffusion. Post-contrast MRI showed enhancement at the periphery of the complex lesion. There was also entrapment of the left lateral ventricle. After placement of an external ventricular drain for hydrocephalus, surgical biopsy of the lesion demonstrated numerous uniform, septate, fungal hyphae with rare acute angle branching consistent with aspergillus. Throughout the admission, there had been slow, but progressive, decline in neurological function. The patient has been continued on antifungal therapy pending improvement in neurological function.
Conclusion: Isolated intraventricular aspergillus infection is a rare manifestation of CNS fungal infection, most commonly seen in immunocompromised patients. Given the nonspecific clinical symptoms of this diagnosis, imaging can localize and narrow the vast differential for these CNS lesions. Patients that have been diagnosed as such require immediate, long-term, and systemic antifungal therapy. With the mortality rate of patients with intraventricular aspergillus infections being highly dependent on accurate and immediate diagnosis, recognizing key imaging features can aid in improving current poor outcomes.https://scholarlycommons.henryford.com/merf2020caserpt/1097/thumbnail.jp
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Modeling Windows in Energy Plus with Simple Performance Indices
The building energy simulation program, Energy Plus (E+), cannot use standard window performance indices (U, SHGC, VT) to model window energy impacts. Rather, E+ uses more accurate methods which require a physical description of the window. E+ needs to be able to accept U and SHGC indices as window descriptors because, often, these are all that is known about a window and because building codes, standards, and voluntary programs are developed using these terms. This paper outlines a procedure, developed for E+, which will allow it to use standard window performance indices to model window energy impacts. In this 'Block' model, a given U, SHGC, VT are mapped to the properties of a fictitious 'layer' in E+. For thermal conductance calculations, the 'Block' functions as a single solid layer. For solar optical calculations, the model begins by defining a solar transmittance (Ts) at normal incidence based on the SHGC. For properties at non-normal incidence angles, the 'Block' takes on the angular properties of multiple glazing layers; the number and type of layers defined by the U and SHGC. While this procedure is specific to E+, parts of it may have applicability to other window/building simulation programs
An Immersed Interface Method for Discrete Surfaces
Fluid-structure systems occur in a range of scientific and engineering
applications. The immersed boundary(IB) method is a widely recognized and
effective modeling paradigm for simulating fluid-structure interaction(FSI) in
such systems, but a difficulty of the IB formulation is that the pressure and
viscous stress are generally discontinuous at the interface. The conventional
IB method regularizes these discontinuities, which typically yields low-order
accuracy at these interfaces. The immersed interface method(IIM) is an IB-like
approach to FSI that sharply imposes stress jump conditions, enabling
higher-order accuracy, but prior applications of the IIM have been largely
restricted to methods that rely on smooth representations of the interface
geometry. This paper introduces an IIM that uses only a C0 representation of
the interface,such as those provided by standard nodal Lagrangian FE methods.
Verification examples for models with prescribed motion demonstrate that the
method sharply resolves stress discontinuities along the IB while avoiding the
need for analytic information of the interface geometry. We demonstrate that
only the lowest-order jump conditions for the pressure and velocity gradient
are required to realize global 2nd-order accuracy. Specifically,we show
2nd-order global convergence rate along with nearly 2nd-order local convergence
in the Eulerian velocity, and between 1st-and 2nd-order global convergence
rates along with 1st-order local convergence for the Eulerian pressure. We also
show 2nd-order local convergence in the interfacial displacement and velocity
along with 1st-order local convergence in the fluid traction. As a
demonstration of the method's ability to tackle complex geometries,this
approach is also used to simulate flow in an anatomical model of the inferior
vena cava.Comment: - Added a non-axisymmetric example (flow within eccentric rotating
cylinder in Sec. 4.3) - Added a more in-depth analysis and comparison with a
body-fitted approach for the application in Sec. 4.
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