Mathematical analysis of a discrete fracture model coupling Darcy flow in the matrix with Darcy-Forchheimer flow in the fracture

We consider a model for flow in a porous medium with a fracture in which the flow in the fracture is governed by the Darcy-Forchheimer law while that in the surrounding matrix is governed by Darcy's law. We give an appropriate mixed, variational formulation and show existence and uniqueness of the solution. To show existence we give an analogous formulation for the model in which the Darcy-Forchheimer law is the governing equation throughout the domain. We show existence and uniqueness of the solution and show that the solution for the model with Darcy's law in the matrix is the weak limit of solutions of the model with the Darcy-Forchheimer law in the entire domain when the Forchheimer coefficient in the matrix tends toward zero

Space-time domain decomposition for advection-diffusion problems in mixed formulations

This paper is concerned with the numerical solution of porous-media flow and transport problems , i. e. heterogeneous, advection-diffusion problems. Its aim is to investigate numerical schemes for these problems in which different time steps can be used in different parts of the domain. Global-in-time, non-overlapping domain-decomposition methods are coupled with operator splitting making possible the different treatment of the advection and diffusion terms. Two domain-decomposition methods are considered: one uses the time-dependent Steklov--Poincar{\'e} operator and the other uses optimized Schwarz waveform relaxation (OSWR) based on Robin transmission conditions. For each method, a mixed formulation of an interface problem on the space-time interface is derived, and different time grids are employed to adapt to different time scales in the subdomains. A generalized Neumann-Neumann preconditioner is proposed for the first method. To illustrate the two methods numerical results for two-dimensional problems with strong heterogeneities are presented. These include both academic problems and more realistic prototypes for simulations for the underground storage of nuclear waste

Bacterial Foodborne Disease: Medical Costs and Productivity Losses

Microbial pathogens in food cause an estimated 6.5-33 million cases of human illness and up to 9,000 deaths in the United States each year. Over 40 different foodborne microbial pathogens, including fungi, viruses, parasites, and bacteria, are believed to cause human illnesses. For six bacterial pathogens, the costs of human illness are estimated to be $9.3-$12.9 billion annually. Of these costs, $2.9-$6.7 billion are attributed to foodborne bacteria. These estimates were developed to provide analytical support for USDA's Hazard Analysis and Critical Control Point (HACCP) systems rule for meat and poultry. (Note that the parasite Toxoplasma gondii is not included in this report.) To estimate medical costs and productivity losses, ERS uses four severity categories for acute illnesses: those who did not visit a physician, visited a physician, were hospitalized, or died prematurely. The lifetime consequences of chronic disease are included in the cost estimates for E. coli O157:H7 and fetal listeriosis.cost-of-illness, foodborne pathogens, lost productivity, medical costs, Food Consumption/Nutrition/Food Safety, Health Economics and Policy,

The diffuse ionized interstellar medium perpendicular to the plane of NGC 891

In an attempt to study the structure and the properties of the diffuse ionized interstellar medium perpendicular to the plane of disk galaxies researchers obtained H alpha images and spectra of NGC 891. Perhaps the most remarkable property of the H alpha emission line in NGC 891 is its extension out of the plane of the galaxy: researchers are able to measure the H alpha line out to more than 30 seconds (1.4 kpc) from the midplane. This means that the ionized hydrogen extends at least four times higher than the neutral hydrogen layer. An anomalously large scale-height for the ionized gas of approx. equals 1 kpc is also found in the Milky Way. The echelle spectra show a changing ratio of NII to H alpha. This excludes the possibility that the large scaleheight of the emission is due to scattering of disk emission by dust high above the plane. The z-extent of the H alpha emission is confirmed by the imaging result. The large z-extent of the ionized gas is confined to the inner half of the visible disk. In this inner region the H alpha distribution also shows a filamentary structure of the diffuse ionized medium. These filaments, sticking out of the plane, originate in HII regions in the plane. The H alpha image also shows a large scale asymmetry if the NE and SW parts of the disk are compared. The NE part is more prominent and extended in H alpha. The same asymmetry is also seen in the radio continuum distribution. This correlation between the diffuse ionized medium and the distribution of relativistic electrons is one example of a relation between star formation processes in the disk and the various components of the halo. Thermal filaments or spurs which are related to HII regions are also known in the Galaxy. These filamentary structures perpendicular to the galactic planes may represent the chimneys which result in the supernova dominated model of the Interstellar Medium by Norman and Ikeuchi (1989)

Flood risk perception near intermediate-sized Kansas dams

Doctor of PhilosophyDepartment of GeographyLisa M HarringtonKansas ranks second in the largest number of dams in the United States, behind Texas (FEMA 2015). In 2020, Kansas dams reached an average age of 52 years, with many exceeding their designed life expectancy or in need of rehabilitation. Climate change and increased urbanization projections suggest more frequent and extreme flooding in the future, requiring greater demands on current infrastructure (O’Neill et al., 2016). Researchers have explored the physical side of flood risk management to a considerable extent. Still, relatively little is known about how flood risk perception varies in areas associated with at-risk dams. Local populations near intermediate-sized dams are less likely to receive attention due to their size and remoteness but are often more susceptible to failures because of dam construction type and design, lack of knowledge or awareness of dam and reservoir conditions, and irregular maintenance. Dam selection was based on the size and age of the structure, primary purpose, and location. Specifically, dams had to be at least 50 years in age, intended mainly for flood control, and likely to experience increased frequency and more intense 24-hour rainfall totals in the future. Understanding risk perceptions now will help prepare decision-makers for communicating with residents and dealing with disaster situations in the near future. A sequential mixed methods design was applied, whereby quantitative and qualitative approaches were used successively to gain in-depth individual perspectives from selected residents and insights from water resource experts on flood risk perception near at-risk dams. The combination of individual risk evaluations and in-depth personal insights provided by this mixed methodology not only provides basic information about the status of thinking about potential dam hazards, but also may be useful for developing strategies that address risk for people living near intermediate-sized dams. Questionnaires were mailed to 1,100 randomly sampled households near ten selected dam sites in eastern Kansas Purposefully selected interviews were conducted with dam safety and water resource experts associated with the selected dams. Closed-ended data provided through questionnaire responses were analyzed through correlation and contingency analyses to explore statistical significance. Qualitative thematic analysis of interviews and open-ended responses provided depth to the close-ended material, in addition to providing another perspective of flood risk perception near aging dams from dam safety and water resource experts. The quantitative results suggested that flood risk perception was higher among residents located within flood zones, but respondents generally were not concerned with the efficacy of aging dams in their locales. The qualitative results identified and explained variations in outcomes for flood experiences, expectations of the dam in its current state and in the event of a dam failure, flood vulnerability, and risk communication. They provide insight on concerns related to dam management, recent flood events, and of how perception relates to physical risk based on location. A significant concern was the lack of accessible and accurate data for intermediate-sized dams that would contribute to local knowledge on flood risk and improved emergency preparedness for high-risk dams. Intensification of education about dams and flood risk awareness near intermediate-sized dams in Kansas appears to be needed, based on this research. It is likely that such needs also are present in other states. Follow-up research should be conducted to determine the statewide perception of aging dams and their potential to exacerbate flood risks in additional areas. Similar studies should be pursued elsewhere

Economic Assessment of Food Safety Regulations: The New Approach to Meat and Poultry Inspection

USDA is now requiring all Federally inspected meat and poultry processing and slaughter plants to implement a new system called Hazard Analysis and Critical Control Points (HACCP) to reduce potentially harmful microbial pathogens in the food supply. This report finds that the benefits of the new regulations, which are the medical costs and productivity losses that are prevented when foodborne illnesses are averted, will likely exceed the costs, which include spending by firms on sanitation, temperature control, planning and training, and testing. Other, nonregulatory approaches can also improve food safety, such as providing market incentives for pathogen reduction, irradiation, and education and labeling to promote safe food handling and thorough cooking.food safety, foodborne illness, microbial pathogens, meat and poultry inspection, HACCP, cost of illness, consumer education, irradiation, Food Consumption/Nutrition/Food Safety, Livestock Production/Industries,

Marshall University Music Department Presents Monty Cole, clarinet, Jean Roberts, piano

https://mds.marshall.edu/music_perf/1204/thumbnail.jp