Analysis of whisker-toughened ceramic components: A design engineer's viewpoint

The use of ceramics components in gas turbines, cutting tools, and heat exchangers has been limited by the relatively low flaw tolerance of monolithic ceramics. The development of whisker toughened ceramic composites offers the potential for considerable improvement in fracture toughness as well as strength. However, the variability of strength is still too high for the application of deterministic design approaches. Several phenomenological reliability theories proposed for this material system are reviewed and the development is reported of a public domain computer algorithm. This algorithm, when coupled with a general purpose finite element program, predicts the fast fracture reliability of a structural component under multiaxial loading conditions

Noninteractive Macroscopic Reliability Model for Ceramic Matrix Composites With Orthotropic Material Symmetry

A macroscopic noninteractive reliability model for ceramic matrix composites is presented. The model is multiaxial and applicable to composites that can be characterized as orthotropic. Tensorial invariant theory is used to create an integrity basis with invariants that correspond to physical mechanisms related to fracture. This integrity basis is then used to construct a failure funciton per unit volume (or area) of material. It is assumed that the overall strength of the composite is governed by weakest link theory. This leads to a Weibull type model similar in nature to the principle of independent action (PIA) model for isotropic monolithic ceramics. An experimental program to obtain model parameters is briefly discussed. In addition, qualitative features of the model are illustrated by presenting reliability surfaces for various model parameters

Using Convolutional Neural Networks to identify Gravitational Lenses in Astronomical images

The Euclid telescope, due for launch in 2021, will perform an imaging and slitless spectroscopy survey over half the sky, to map baryon wiggles and weak lensing. During the survey Euclid is expected to resolve 100,000 strong gravitational lens systems. This is ideal to find rare lens configurations, provided they can be identified reliably and on a reasonable timescale. For this reason we have developed a Convolutional Neural Network (CNN) that can be used to identify images containing lensing systems. CNNs have already been used for image and digit classification as well as being used in astronomy for star-galaxy classification. Here our CNN is trained and tested on Euclid-like and KiDS-like simulations from the Euclid Strong Lensing Group, successfully classifying 77% of lenses, with an area under the ROC curve of up to 0.96. Our CNN also attempts to classify the lenses in COSMOS HST F814W-band images. After convolution to the Euclid resolution, we find we can recover most systems that are identifiable by eye. The Python code is available on Github

A latest Cretaceous to earliest Paleogene dinoflagellate cyst zonation of Antarctica, and implications for phytoprovincialism in the high southern latitudes

The thickest uppermost Cretaceous to lowermost Paleogene (Maastrichtian to Danian) sedimentary succession in the world is exposed on southern Seymour Island (65° South) in the James Ross Basin, Antarctic Peninsula. This fossiliferous shallow marine sequence, which spans the Cretaceous–Paleogene boundary, has allowed a high-resolution analysis of well-preserved marine palynomorphs. Previous correlation of Cretaceous–Paleogene marine palynomorph assemblages in the south polar region relied on dinoflagellate cyst biozonations from New Zealand and southern Australia. The age model of the southern Seymour Island succession is refined and placed within the stratigraphical context of the mid to high southern palaeolatitudes. Quantitative palynological analysis of a new 1102 m continuous stratigraphical section comprising the uppermost Snow Hill Island Formation and the López de Bertodano Formation (Marambio Group) across southern Seymour Island was undertaken. We propose the first formal late Maastrichtian to early Danian dinoflagellate cyst zonation scheme for the Antarctic based on this exceptional succession. Two new late Maastrichtian zones, including three subzones, and one new early Danian zone are defined. The oldest beds correlate well with the late Maastrichtian of New Zealand. In a wider context, a new South Polar Province based on Maastrichtian to Danian dinoflagellate cysts is proposed, which excludes most southern South American marine palynofloras. This interpretation is supported by models of ocean currents around Antarctica and implies an unrestricted oceanic connection across Antarctica between southern South America and the Tasman Sea

A Tailored Systems Engineering Framework for Science and Technology Projects

As government and industry becomes subject to a wider range of technology initiatives, science and technology (S&T) research project leadership recognizes the need to incorporate more systems engineering (SE) rigor into their projects. The objective of this research is to develop a tailorable systems engineering framework for S&T project planning, execution, assessment and transition. The key deliverable is an Excel-based tool instantiating the SE framework for a wide range of S&T projects in technology development organizations. It includes a report with tailored methods based on programmatic discriminants. To develop this framework, a comprehensive understanding of SE principles is applied to several case studies across government and supporting industry-sponsored S&T activities. This research followed a six-step approach: (1) Literature Review; (2) Formulate Taxonomy; (3) Prepare Data Gathering Approach; (4) Review Case Studies; (5) Develop Tailorable SE Framework for Technology Development and Transition; and (6) Validate Framework.The framework allows S&T project leaders and engineers to customize a recommended set of SE processes, methods and tools for their specific project type, size, maturity, budget, and integration level. Recommendations for SE methods are made at a summary level, with additional details available for desired activities. References to established SE documentation is also included for further investigation of appropriate SE techniques

A role for glycolipid biosynthesis in severe fever with thrombocytopenia syndrome virus entry

A novel bunyavirus was recently found to cause severe febrile illness with high mortality in agricultural regions of China, Japan, and South Korea. This virus, named severe fever with thrombocytopenia syndrome virus (SFTSV), represents a new group within the Phlebovirus genus of the Bunyaviridae. Little is known about the viral entry requirements beyond showing dependence on dynamin and endosomal acidification. A haploid forward genetic screen was performed to identify host cell requirements for SFTSV entry. The screen identified dependence on glucosylceramide synthase (ugcg), the enzyme responsible for initiating de novo glycosphingolipid biosynthesis. Genetic and pharmacological approaches confirmed that UGCG expression and enzymatic activity were required for efficient SFTSV entry. Furthermore, inhibition of UGCG affected a post-internalization stage of SFTSV entry, leading to the accumulation of virus particles in enlarged cytoplasmic structures, suggesting impaired trafficking and/or fusion of viral and host membranes. These findings specify a role for glucosylceramide in SFTSV entry and provide a novel target for antiviral therapies

Beaverdale Neighborhood Charter Plan Update

In September of 2011, the Beaverdale Neighborhood Association (BNA) filed an application to participate in the pilot Charter Neighborhood Program in order to update its original plan that was approved in 1991 with new goals for the future. On November 21, 2011, the Des Moines City Council approved the selection of Beaverdale as one of the five neighborhoods to participate in the Charter Neighborhood Program. Neighborhoods selected for the pilot program worked with City staff as well as graduate students from Iowa State University’s Department of Community and Regional Planning (ISU Planning Team) to update their respective neighborhood plans. Over the past two decades, major goals in the first Beaverdale Neighborhood plan have been accomplished. However, new issues have emerged as well, which brings about the need to establish a strategic plan for the Beaverdale Neighborhood for the next 5 to 10 years.https://lib.dr.iastate.edu/resilientneighborhoods_plans/1003/thumbnail.jp

Analysis of Whisker-Toughened Ceramic Components -- A Design Engineer\u27s Viewpoint

The use of ceramics components in gas turbines, cutting tools, and heat exchangers has been limited by the relatively low flaw tolerance of monolithic ceramics. The development of whisker-toughened ceramic composites offers the potential for considerable improvement in fracture toughness as well as strength. However, the variability of strength is still too high for the application of deterministic design approaches. This report reviews several phenomenological reliability theories proposed for this material system, and reports on the development of a public domain computer algorithm. This algorithm, when coupled with a general-purpose finite element program, predicts the fast fracture reliability of a structural component under multiaxial loading conditions

Diffusion of Computer Applications Among Physicians: A Quasi-Experimental Study

An experimental program involving the use of a hospital information system was implemented and evaluated on four services at Methodist Hospital of Indiana, a 1120-bed, private teaching hospital. Ten other hospital services were assigned to a control group. The program utilized educationally influential physicians to disseminate information concerning the advantages of using predesigned computer-stored personal order sets for the entry of medical orders into a hospital information system. Data from the hospital information system\u27s tapes were collected at three times in order to evaluate the effectiveness of the intervention. A multivariate analysis of variance indicated that the program resulted in a significant increase in personal order set use by physicians, physician assistants, and unit secretaries on the experimental services. The results of the study suggest that the identification and use of educationally influential physicians is an effective means of introducing medical innovations into clinical settings

Walking abnormalities are associated with COPD: An investigation of the NHANES III dataset

Research on the peripheral effects of COPD has focused on physiological and structural changes. However, different from muscular weakness or decreased physical activity, mechanical abnormalities of the muscular system, e.g. walking, have yet to be investigated. Our purpose was to utilize the National Health and Nutritional Examination Survey (NHANES) dataset to determine whether walking abnormalities are associated with COPD severity. To determine if walking abnormalities were independently associated with COPD severity, our analysis aimed to investigate the association of physical activity levels with COPD severity and with walking abnormalities. The NHANES III dataset that contains data for 31,000 persons that were collected from 1988 to 1994, was used to explore the association of COPD severity on gross walking abnormalities, i.e. limp, shuffle, etc. Logistic regression models were created using FEV1/FVC ratio, age, gender, BMI, and smoking status as predictors of walking abnormalities and physical activity in persons aged 40 to 90 years old. Results demonstrated a significant correlation between the presence of walking abnormalities and severe COPD (odds ratio: 1.97; 95% CI: 1.1 to 3.5). This suggests that disease severity can contribute to mechanical outcomes of patients with COPD. In addition, decreased physical activity levels were significantly associated with all COPD severity levels with the exception of mild COPD. The association between altered gait and COPD status may be due to the presence of physical inactivity that is present in patients with COPD. Future research directions should include investigating more closely the mechanical outcomes of persons with COPD