78 research outputs found

    An Infrastructure to Support Data Integration and Curation for Higher Educational Research

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    The recent challenges for higher education call for research that can offer a comprehensive understanding about the performance and efficiency of higher education institutions in their three primary missions: research, education, and service. In other for this to happen, it is necessary for researchers to have access to a multitude of data sources.However, due to the nature of their academic training, many higher education practitioners do not have access to expertise in working with different data sources. In this work, we describe a design and implementation for an infrastructure that will bring together the tools and the data to provide access to researchers in the field of higher education institutional research. The infrastructure will include integration and curation for data from different sources, embedded statistical environment, high performance computational back-end, and extensibility for future Big Data and unstructured data

    Matrix Cracking of Ceramic-Matrix Composites

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    In this chapter, the matrix cracking of fiber-reinforced ceramic-matrix composites (CMCs) is investigated using the energy balance approach. The relationship between the matrix cracking stress, fiber and interface oxidation, and fiber failure is established. The effects of the fiber volume, interface shear stress and interface debonding energy, fiber failure, and oxidation temperature on the time-dependent matrix cracking stress are analyzed. The experimental matrix cracking stress of different fiber-reinforced CMCs is predicted using the present models

    Cutting force and specific energy for rotary ultrasonic drilling based on kinematics analysis of vibration effectiveness

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    Rotary ultrasonic drilling (RUD) has become an effective approach for machining advanced composites which are widely using in the field of aeronautics. The cutting kinematics and the corresponding material removal mechanisms are distinct in different drilling areas during RUD. However, these fundamentals have not been fully considered in the existing studies. In this research, two distinct forms of interaction induced by ultrasonic vibration were considered as impact-separation and vibratory lapping between the abrasives and workpiece. And the conditions to guarantee the effectiveness of these interactions were obtained to eliminate diminishing effects of ultrasonic vibration. Based on indentation fracture theory, the penetration depth of abrasives and the axial drilling force model was derived for RUD. The verification tests of C/SiC composites resulted in a prediction error within 15%. Due to the minimal volume of material removed during each vibration cycle, the drilling force was more stable in vibration assisted mode. The specific drilling energy of RUD was firstly calculated based on the measured drilling load. It was found the drilling parameters should be matched with vibration frequency and amplitude to make better usage of the advantages of ultrasonic vibration, which is critical in the vibration assisted processing of advanced materials

    Global variation in diabetes diagnosis and prevalence based on fasting glucose and hemoglobin A1c

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    Fasting plasma glucose (FPG) and hemoglobin A1c (HbA1c) are both used to diagnose diabetes, but these measurements can identify different people as having diabetes. We used data from 117 population-based studies and quantified, in different world regions, the prevalence of diagnosed diabetes, and whether those who were previously undiagnosed and detected as having diabetes in survey screening, had elevated FPG, HbA1c or both. We developed prediction equations for estimating the probability that a person without previously diagnosed diabetes, and at a specific level of FPG, had elevated HbA1c, and vice versa. The age-standardized proportion of diabetes that was previously undiagnosed and detected in survey screening ranged from 30% in the high-income western region to 66% in south Asia. Among those with screen-detected diabetes with either test, the age-standardized proportion who had elevated levels of both FPG and HbA1c was 29-39% across regions; the remainder had discordant elevation of FPG or HbA1c. In most low- and middle-income regions, isolated elevated HbA1c was more common than isolated elevated FPG. In these regions, the use of FPG alone may delay diabetes diagnosis and underestimate diabetes prevalence. Our prediction equations help allocate finite resources for measuring HbA1c to reduce the global shortfall in diabetes diagnosis and surveillance

    Global variations in diabetes mellitus based on fasting glucose and haemogloblin A1c

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    Fasting plasma glucose (FPG) and haemoglobin A1c (HbA1c) are both used to diagnose diabetes, but may identify different people as having diabetes. We used data from 117 population-based studies and quantified, in different world regions, the prevalence of diagnosed diabetes, and whether those who were previously undiagnosed and detected as having diabetes in survey screening had elevated FPG, HbA1c, or both. We developed prediction equations for estimating the probability that a person without previously diagnosed diabetes, and at a specific level of FPG, had elevated HbA1c, and vice versa. The age-standardised proportion of diabetes that was previously undiagnosed, and detected in survey screening, ranged from 30% in the high-income western region to 66% in south Asia. Among those with screen-detected diabetes with either test, the agestandardised proportion who had elevated levels of both FPG and HbA1c was 29-39% across regions; the remainder had discordant elevation of FPG or HbA1c. In most low- and middle-income regions, isolated elevated HbA1c more common than isolated elevated FPG. In these regions, the use of FPG alone may delay diabetes diagnosis and underestimate diabetes prevalence. Our prediction equations help allocate finite resources for measuring HbA1c to reduce the global gap in diabetes diagnosis and surveillance.peer-reviewe

    Perspectives on acoustics in environmental design

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    Reviews the significance of acoustics in environmental design, noting that research on the office environment reveals that acoustics is a primary source of dissatisfaction. Problems of the hearing impaired are discussed, and design suggestions are offered. The significance of acoustic images, memories, and perceptions is also considered.Source type: Electronic(1
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