Investigating the micromechanisms of mode II delamination in composite laminates

The use of composite materials in primary aerospace structures is continually increasing due to their high stiffness and high strength to weight ratios. However, composite laminates are susceptible to delamination which can lead to the loss of global stiffness and potentially to catastrophic failure. Delamination is therefore a critical damage mechanism to account for when determining the durability and damage tolerance of composite materials. A large amount of research has already been carried out to investigate delamination and a number of failure criteria have been developed to predict delamination growth. However, the majority of these criteria are not based on the physical mechanisms that cause interlaminar fracture. Thus to be able to confidently predict delamination growth in real world applications a physically based failure criteria would be more appropriate. The key to developing physically based criteria is through fractographic observations to determine the dominant failure mechanisms of delamination. Thus the purpose of this research was to characterise the failure process of mode II shear fracture, and in particular to determine the formation of cusp features prevalent to mode II dominated fracture. A polyvinylchloride foam was used to macro-simulate mode II interlaminar failure of composite laminates. The in-situ fracture process was characterised successfully and the energy absorbed during cusp formation was determined. Results were compared with cusp formation in two carbon-fibre/epoxy laminates and the post fracture morphology of all the materials was similar. In addition the influence of parameters such as, material type, inter-fibre spacing, fibre diameter and ply orientation on the frequency, morphology and size of cusp formation were also investigated. Results indicated that cusp formation was via the initiation, saturation and propagation of tensile microcracks and that neither the cusp formation process nor the energy associated with crack formation was found to be influenced by the parameters studied

Millennial Consumer Preference: Waffle Fries vs. Potato Wedges

For this experiment, two groups of paid volunteers, aged 18-34, provided written quantitative and qualitative data on preferences between waffle fries (test) and potato wedges (control). Each participant provided demographic information and then answered a series of questions, using a hedonic rating scale or by composing a written response. Participants also provided qualitative data about what influenced their preference between the test and control. The experiment confirmed the hypothesis was correct: Millennials prefer waffle fries over potato wedges. It also confirms that Millennials prefer a unique, crunchy, crispy, and decreased potato filled product. Millennial consumers reported significant preference of the waffle fry over the wedge. The results also confirm consumers preferred the crispiness and amount of potato filling of the waffle fry over the wedge

Teaching Government Information in Information Literacy Credit Classes

This paper reviews the teaching of credit-bearing information literacy courses and government information, reports questionnaire responses from librarians who teach these courses, and argues that revising the ways we teach government information in for-credit courses will help students achieve information literacy. A focus on government information as critical thinking and subject access resources, rather than as unique documents collections or formats, can remove barriers for researchers, particularly in classes that allow students an entire term to develop skills. In addition, librarians will increase their comfort levels addressing government information and develop ways to teach students to use these resources within a meaningful context for their research. The ability to find, evaluate, and effectively use government information resources will empower students to become lifelong learners, seekers, and even engaged citizens, whatever their post-graduation information needs may be

REVIEW: At Home in Mossy Creek

Review of the shared novel At Home in Mossy Creek, by Debra Leigh Smith, Sandra Chastain, Debra Dixon, and Martha Crockett, with others

EVALUATING THE RELATIONSHIP BETWEEN DEPRESSION, COGNITIVE PERFORMANCE AND QUALITY OF LIFE FOLLOWING TRAUMATIC BRAIN INJURY WITHIN THE CONTEXT OF THE CHRONIC CARE MODEL

Depression is the most common mood disorder after traumatic brain injury (TBI). This study evaluated how the presence and/or severity of depression post-TBI affect a person's cognitive status and quality of life (QOL). Demographic variables, injury severity, and pre-morbid psychiatric histories were documented from patient interview and medical records. Persons with TBI were assessed at 6 and 12 months post-injury for posttraumatic depression using the Patient Health Questionnaire (PHQ-9). They were also evaluated for cognitive status and QOL at the same time points. Results indicate that persons with moderate/severe TBI exhibit worse cognitive status and report lower QOL post-injury than persons with no depression. Persons with mild depression report lower QOL than persons with no depression, but do not display worse cognitive functioning. The severity of posttraumatic depression, not just the presence of depression, affects a person's cognitive status and QOL after injury. TBI and posttraumatic depression are chronic conditions. The Chronic Care Model is a framework for identifying and improving care at multiple levels within the health care system including delivery system design, decision support, clinical information systems, self-management support, and within the community. The current health care delivery for persons with TBI suffering from posttraumatic depression and treated in southwestern Pennsylvania is discussed and areas for improvement within the system are identified. The public health significance of this research is important for understanding the relationship of depression, cognition and QOL after TBI and effectively targeting persons with posttraumatic depression to formulate interventions which allow for better outcome and QOL post-injury

Effects of codesign on consumer acceptance of a wearable technology using the Lilypad Arduino, The

2019 Fall.Includes bibliographical references.Wearable technology is increasing in popularity, but research shows that significant challenges still exist in user acceptance. Meanwhile, new tools and design and development contexts are becoming accessible to the average consumer, through which they may more actively engage in the creation of products. This experimental study utilized a mixed-method approach to examine the effect of a codesign context on user acceptance of a wearable technology using the open-source wearable microcontroller, the Lilypad Arduino. Data were collected via two codesign sessions held for 17 adult participants in a western region of the United States; each session comprised a hands-on codesign activity, focus group discussion, and pre- and post-assessment surveys. Direct content analysis was conducted based on the extended Technology Acceptance Model (perceived ease of use, perceived usefulness, and perceived playfulness) as a theoretical framework upon which qualitative data from focus group discussions were arranged; paired-samples comparison analyses were conducted for survey data. Results from both the quantitative and qualitative data revealed that the codesign activity prompted a positive increase in all variables tested; implications are discussed as well as recommendations for further study

Sublethal Toxicity of Microcystis and Microcystin-LR in Fish

The occurrence of blooms of toxic cyanobacteria in freshwater environments is a global ecological and public health concern. Species of Microcystis are of particular importance because blooms occur in many freshwater environments throughout the world and microcystin toxin concentrations can exceed World Health Organization advisory levels. While microcystin has been associated with fish kills, sublethal effects of chronic exposure at environmentally relevant concentrations are relatively unknown. The objective of this research was to evaluate toxicity of microcystin and Microcystis in fish during all life history stages. We evaluated global gene expression response in larval zebrafish (Danio rerio), and a sub-set of biomarker genes indicative of microcystin exposure were identified. In addition, vitellogenin genes were highly up-regulated in zebrafish exposed to Microcystis but not the microcystin toxin, indicating potential endocrine disrupting effects of Microcystis blooms. Effects on reproduction were evaluated in adult zebrafish exposed to Microcystis. There was a significant decrease in the percentage of adults that spawned, however fecundity and larval survival were not affected. Laboratory mesocosm experiments with channel catfish (Ictalurus punctatus) were also conducted to determine the importance of dietary and aqueous exposure in microcystin bioaccumulation and assess histopathological lesions. Tissue toxin concentrations and histopathological lesions were also evaluated in channel catfish collected from Lake Erie and Waterville Reservoir, North Carolina to monitor fish living in environments affected by Microcystis blooms and relate responses to those observed in laboratory exposures

Road Salt-Induced Salinization of the Upper Paulins Kill River in Newton, New Jersey

Road salt application is a primary factor leading to the salinization of freshwater rivers and streams throughout the Northeastern United States and globally. Rising salinization within fresh water bodies is problematic because it can modify community structure and detritus processing within freshwater ecosystems, induce mortality among macroinvertebrates and other aquatic life, and mobilize metals that can pose harm to human health. Road salts also threaten surface and underground drinking water supplies, kill riparian vegetation, and corrode infrastructure, such as bridges and roads. This research examines 4 1⁄2 years of continuous water quality monitoring data collected from two sensor stations along the Paulins Kill River in Newton, New Jersey to assess the seasonal impact that road salt is having on the river. Specific conductance and depth were examined during each season. The data showed that if precipitation fell when air temperatures were above freezing, conductivity and depth exhibited an inverse relationship. The additional freshwater from rainwater diluted the concentration of ions in the river, causing conductivity measurements to decrease as the river depth rose. When precipitation occurred when air temperatures were below freezing, however, conductivity levels rose along with the river’s depth because road departments were applying road salt to Newton’s streets. This research provides important implications for winter road management by public works departments and their impacts on local rivers