Plasma and cold sprayed aluminum carbon nanotube composites: Quantification of nanotube distribution and multi-scale mechanical properties

Carbon nanotubes (CNT) could serve as potential reinforcement for metal matrix composites for improved mechanical properties. However dispersion of carbon nanotubes (CNT) in the matrix has been a longstanding problem, since they tend to form clusters to minimize their surface area. The aim of this study was to use plasma and cold spraying techniques to synthesize CNT reinforced aluminum composite with improved dispersion and to quantify the degree of CNT dispersion as it influences the mechanical properties. Novel method of spray drying was used to disperse CNTs in Al-12 wt.% Si prealloyed powder, which was used as feedstock for plasma and cold spraying. A new method for quantification of CNT distribution was developed. Two parameters for CNT dispersion quantification, namely Dispersion parameter (DP) and Clustering Parameter (CP) have been proposed based on the image analysis and distance between the centers of CNTs. Nanomechanical properties were correlated with the dispersion of CNTs in the microstructure. Coating microstructure evolution has been discussed in terms of splat formation, deformation and damage of CNTs and CNT/matrix interface. Effect of Si and CNT content on the reaction at CNT/matrix interface was thermodynamically and kinetically studied. A pseudo phase diagram was computed which predicts the interfacial carbide for reaction between CNT and Al-Si alloy at processing temperature. Kinetic aspects showed that Al4C3 forms with Al-12 wt.% Si alloy while SiC forms with Al-23wt.% Si alloy. Mechanical properties at nano, micro and macro-scale were evaluated using nanoindentation and nanoscratch, microindentation and bulk tensile testing respectively. Nano and micro-scale mechanical properties (elastic modulus, hardness and yield strength) displayed improvement whereas macro-scale mechanical properties were poor. The inversion of the mechanical properties at different scale length was attributed to the porosity, CNT clustering, CNT-splat adhesion and Al 4C3 formation at the CNT/matrix interface. The Dispersion parameter (DP) was more sensitive than Clustering parameter (CP) in measuring degree of CNT distribution in the matrix.

Immigrant high school students' in-depth understandings of the value of heritage language and bilingualism

The purpose of this research was to explore perceptions among 9 th through 12th grade students from Brazil, Haiti and Jamaica, with respect to their heritage languages: Portuguese, Haitian Creole, and Jamaican Patois. An additional purpose was to understand in greater detail possible variations of perception with respect to heritage language maintenance (or loss) in relation to one’s gender, first language, and place of birth. The research implemented semi-structured interviews with male and female adolescents with these heritage language backgrounds. Participants’ responses were recorded and transcribed. The transcriptions were analyzed via a categorizing of themes emerging from the data. Data were analyzed using inductive analysis. Three categories emerged from the inductive analysis of the data: (a) heritage language, (b) bilingualism, and (c) English as a second language. The analysis reveals that as participants learn English, they continue to value their heritage language and feel positively toward bilingualism, but differ in their preference regarding use of native language and English in a variety of contexts. There seems to be a mismatch between a positive attitude and an interest in learning their heritage language. Families and teachers, as agents, may not be helping students fully understand the advantages of bilingualism. Students seem to have a lack of understanding of bilingualism’s cognitive and bi-literacy benefits. Instead, employment seems to be perceived as the number one reason for becoming bilingual. Also, the students have a desire to add culture to the heritage language curriculum. The study was conducted at one of the most diverse and largest high schools in Palm Beach, in Palm Beach County, Florida. The results of this study imply that given the positive attitude toward heritage language and bilingualism, students need to be guided in exploring their understanding of heritage language and bilingualism. Implications for teaching and learning, as well as recommendations for further research, are included.

Geochemical determination of the fate and transport of injected fresh wastewater to a deep saline aquifer

Deep well injection into non-potable saline aquifers of treated domestic wastewater has been used in Florida for decades as a safe and effective alternative to ocean outfall disposal. The objectives of this study were to determine the fate and transport of injected wastewater at two deep well injection sites in Miami Dade County, Florida, USA. Detection of ammonium in the Middle Confining units of the Floridan aquifer above the injection zone at both sites has been interpreted as evidence of upward migration of injected wastewater, posing a risk to underground sources of drinking water. Historical water quality data, including ammonia, chloride, temperature, and pH from existing monitoring wells at both sites from 1983 to 2008, major ions collected monthly from 2006 and 2008, and a synoptic sampling event for stable isotopes, tritium, and dissolved gases in 2008, were used to determine the source of ammonium in groundwater and possible migration pathways. Geochemical modeling was used to determine possible effects of injected wastewater on native water and aquifer matrix geochemistry. Injected wastewater was determined to be the source of elevated ammonium concentrations above ambient water levels, based on the results of major ion concentrations, tritium, dissolved noble gases and 15N isotopes analyses. Various possible fluid migration pathways were identified at the sites. Data for the south site suggest buoyancy-driven vertical pathways to overlying aquifers bypassing the confining units, with little mixing of injected wastewater with native water as it migrated upward. Once it is introduced into an aquifer, the injectate appeared to migrate advectively with the regional groundwater flow. Geochemical modeling indicated that CO 2-enriched injected wastewater allowed for carbonate dissolution along the vertical pathways, enhancing permeability along these flowpaths. At the north site, diffusive upward flow through the confining units or offsite vertical pathways were determined to be possible, however no evidence was detected for any on-site confining unit bypass pathway. No evidence was observed at either site of injected wastewater migration to the Upper Floridan aquifer, which is used as a municipal water supply and for aquifer storage and recovery.

Emotional Intelligence and Organizational Commitment Among Private Club Board and Committee Volunteer Leaders: A Pilot Study

This pilot study explored the relationship between emotional intelligence and organizational commitment among provate club board and committee volunteer members. The top three items, ranked by mean scores, of each of three EI dimensions -- IN, OUT, and RELATIONSHIPS wer discussed. A sample of 57 volunteer leaders furhter was split into high EI and low EI groups based on respndents' overall EO median score. Statistical differences between high and low EI groups in three aspects of organizational commitment - affective, continuance, and normative commitment - wer present. 4 t-test results showed that the difference between high and low EI groups in affective commitment among private club volunteer leaders was statistcally significant at p <.05.

Differential effects of single -sex versus coed education on the mathematical reasoning ability, verbal reasoning ability, and self-concept of high school girls

This study explored the differential effects of single-sex versus coed education on the cognitive and affective development of young women in senior year of high school. The basic research question was: What are the differential effects of single-sex versus coed education on the development of mathematical reasoning ability, verbal reasoning ability, or self-concept of high school girls?^ This study was composed of two parts. In the first part, the SAT verbal and mathematical ability scores were recorded for those subjects in the two schools from which the sample populations were drawn. The second part of the study required the application of the Piers-Harris Children's Self-Concept Scale to subjects in each of the two sample populations. The sample schools were deliberately selected to minimize between group differences in the populations. One was an all girls school, the other coeducational.^ The research design employed in this study was the causal-comparative method, used to explore causal relationships between variables that already exist. Based on a comprehensive analysis of the data produced by this research, no significant difference was found to exist between the mean scores of the senior girls in the single-sex school and the coed school on the SAT 1 verbal reasoning section. Nor was any significant difference found to exist between the mean scores of the senior girls in the single-sex school and the coed school on the SAT 1 mathematical reasoning section. Finally, no significant difference between the mean total scores of the senior girls in the single-sex school and the coed school on the Piers-Harris Children's Self-Concept Scale was found to exist.^ Contrary to what many other studies have found in the past about single-sex schools and their advantages for girls, this study found no support for such advantages in the cognitive areas of verbal and mathematical reasoning as measured by the SAT or in the affective area of self-concept as measured by the Piers-Harris Children's Self-Concept Scale. ^

Modeling the role of investigator bias, interrogation techniques, and suspect decision -making on the likelihood of confession

The purpose of the current study was to attempt to model various cognitive and social processes that are believed to lead to false confessions. More specifically, this study manipulated the variables of experimenter expectancy, guilt-innocence of the suspect, and interrogation techniques using the Russano et al. (2005) paradigm. The primary measure of interest was the likelihood of the participant signing the confession statement. By manipulating experimenter expectancy, the current study sought to further explore the social interactions that may occur in the interrogation room. In addition, in past experiments, the interrogator has typically been restricted to the use of one or two interrogation techniques. In the present study, interrogators were permitted to select from 15 different interrogation techniques when attempting to solicit a confession from participants. ^ Consistent with Rusanno et al. (2005), guilty participants (94%) were more likely to confess to the act of cheating than innocent participants (31%). The variable of experimenter expectancy did not effect confessions rates, length of interrogation, or the type of interrogation techniques used. Path analysis revealed feelings of pressure and the weighing of consequences on the part of the participant were associated with the signing of the confession statement. The findings suggest the guilt/innocence of the participant, the participant's perceptions of the interrogation situation, and length of interrogation play a pivotal role in the signing of the confession statement. Further examination of these variables may provide researchers with a better understanding of the relationship between interrogations and confessions. ^

It takes an institution's village to retain a student: A comprehensive look at two early warning system undergraduate retention programs and administrators' perceptions of students' experiences and the retention services they provide students in the early warning system retention programs

Institutions have implemented many campus interventions to address student persistence/retention, one of which is Early Warning Systems (EWS). However, few research studies show evidence of interventions that incorporate noncognitive factors/skills, and psychotherapy/psycho-educational processes in the EWS. A qualitative study (phenomenological interview and document analysis) of EWS at both a public and private 4-year Florida university was conducted to explore EWS through the eyes of the administrators of the ways administrators make sense of students' experiences and the services they provide and do not provide to assist students. Administrators' understanding of noncognitive factors and the executive skills subset and their contribution to retention and the executive skills development of at-risk students were also explored. Hossler and Bean's multiple retention lenses theory/paradigms and Perez's retention strategies were used to guide the study. Six administrators from each institution who oversee and/or assist with EWS for first time in college undergraduate students considered academically at-risk for attrition were interviewed. Among numerous findings, at Institution X: EWS was infrequently identified as a service, EWS training was not conducted, numerous cognitive and noncognitive issues/deficits were identified for students, and services/critical departments such as EWS did not work together to share students' information to benefit students. Assessment measures were used to identify students' issues/deficits; however, they were not used to assess, track, and monitor students' issues/deficits. Additionally, the institution's EWS did address students' executive skills function beyond time management and organizational skills, but did not address students' psychotherapy/psycho-educational processes. Among numerous findings, at Institution Y: EWS was frequently identified as a service, EWS training was not conducted, numerous cognitive and noncognitive issues/deficits were identified for students, and services/critical departments such as EWS worked together to share students' information to benefit students. Assessment measures were used to identify, track, and monitor students' issues/deficits; however, they were not used to assess students' issues/deficits. Additionally, the institution's EWS addressed students' executive skills function beyond time management and organizational skills, and psychotherapy/psycho-educational processes. Based on the findings, Perez's retention strategies were not utilized in EWS at Institution X, yet were collectively utilized in EWS at Institution Y, to achieve Hossler and Bean's retention paradigms. Future research could be designed to test the link between engaging in the specific promising activities identified in this research (one-to-one coaching, participation in student success workshops, academic contracts, and tutoring) and student success (e.g., higher GPA, retention). Further, because this research uncovered some concern with how to best handle students with physical and psychological disabilities, future research could link these same promising strategies for improving student performance for example among ADHD students or those with clinical depression.

Plasma And Cold Sprayed Aluminum Carbon Nanotube Composites: Quantification Of Nanotube Distribution And Multi-Scale Mechanical Properties

Carbon nanotubes (CNT) could serve as potential reinforcement for metal matrix composites for improved mechanical properties. However dispersion of carbon nanotubes (CNT) in the matrix has been a longstanding problem, since they tend to form clusters to minimize their surface area. The aim of this study was to use plasma and cold spraying techniques to synthesize CNT reinforced aluminum composite with improved dispersion and to quantify the degree of CNT dispersion as it influences the mechanical properties. Novel method of spray drying was used to disperse CNTs in Al-12 wt.% Si pre-alloyed powder, which was used as feedstock for plasma and cold spraying. A new method for quantification of CNT distribution was developed. Two parameters for CNT dispersion quantification, namely Dispersion parameter (DP) and Clustering Parameter (CP) have been proposed based on the image analysis and distance between the centers of CNTs. Nanomechanical properties were correlated with the dispersion of CNTs in the microstructure. Coating microstructure evolution has been discussed in terms of splat formation, deformation and damage of CNTs and CNT/matrix interface. Effect of Si and CNT content on the reaction at CNT/matrix interface was thermodynamically and kinetically studied. A pseudo phase diagram was computed which predicts the interfacial carbide for reaction between CNT and Al-Si alloy at processing temperature. Kinetic aspects showed that Al4C3 forms with Al-12 wt.% Si alloy while SiC forms with Al-23wt.% Si alloy. Mechanical properties at nano, micro and macro-scale were evaluated using nanoindentation and nanoscratch, microindentation and bulk tensile testing respectively. Nano and micro-scale mechanical properties (elastic modulus, hardness and yield strength) displayed improvement whereas macro-scale mechanical properties were poor. The inversion of the mechanical properties at different scale length was attributed to the porosity, CNT clustering, CNT-splat adhesion and Al4C3 formation at the CNT/matrix interface. The Dispersion parameter (DP) was more sensitive than Clustering parameter (CP) in measuring degree of CNT distribution in the matrix.

The relationship between coping strategies and level of depression among spousal caregivers of elders with dementia

Caregivers are often under a great deal of stress while caring for their spouses with dementia. It is when the stress builds up and becomes overwhelming that the caregiver is at risk for developing depression. The primary objective of this study was to determine which cognitive and behavioral coping strategies are associated with lower levels of depression; once these strategies are identified, interventions can be established to educate these caregivers. Thirty-two spousal caregivers participated in this study. They each filled out a questionnaire, which contained three sections. The first section asked them for demographic information about themselves and their spouses; the second section consisted of a coping strategies scale; and, the third section contained a depression scale. Results of this study indicate that problem-focused coping strategies were associated with a lesser degree of depressive symptomatology, whereas most of the emotion-focused strategies were associated with a greater degree of depressive symptomatology among the present sample of spousal caregivers. In addition, no relationship was found between the length of time providing care to their spouses and their level of depression.

Socioemotional Outcomes of Children Sexually Abused during Early Childhood

This study investigated the nature and impact of the sexual abuse of children ages birth through 6 years. The purpose was to enhance knowledge about this understudied population through examination of: (1) characteristics of the abuse; (2) socioemotional developmental outcomes of young victims; and (3) potential moderating effects of family dynamics. An ecological-developmental theoretical framework was applied. Secondary data analysis was conducted using data collected from the consortium Longitudinal Studies of Child Abuse and Neglect (LONGSCAN). A sample of 250 children was drawn from LONGSCAN data, including children who were sexually abused (n=125) and their nonabused counterparts (n=125), matched on demographic variables. Results revealed that young victims of sexual abuse were disproportionately female (91 girls; 73%). The sexual abuse committed against these youngsters was severe in nature, with 111 children (89%) experiencing contact offenses ranging from fondling to forcible rape. Sixty-two percent of child victims demonstrated borderline, clinical, or less than adequate functioning on normative, expected socioemotional outcomes. Child victims reported low degrees of perceived competence and satisfaction in the social environment. When compared with their nonabused counterparts, child victims demonstrated significantly poorer socioemotional functioning, as evidenced by aggressive behaviors, attention and thought problems. Sexually abused youngsters also reported lower self-perceptions of cognitive and physical competence and maternal acceptance. Family dynamic factors did not significantly moderate the relationships between abuse and socioemotional outcomes, with one exception. The caregivers’ degree of empathy for their children had a significant moderating effect on the children’s social problems. This study contributes to an otherwise scant body of literature on the sexual abuse of preschoolers. Findings provide implications for social work practice, especially in the development of assessment and prevention strategies.

People and big cats (Panthera onca and Puma concolor) of the Atlantic Forest, Brazil

Conservation of large felids is not only about collecting ecological information; it is also about understanding people’s values, beliefs, attitudes and behaviour. The overarching goal of this thesis is to assess the relationship between people and jaguars and pumas. Specifically by contributing to the understanding of public acceptance of big cats, as well as the forces (cognitive and social) that influence people’s acceptability. Self-administered questionnaires (n=326) were applied to rural residents outside two protected areas in the State of Sao Paulo: Intervales and PETAR state parks. Findings showed that the acceptability of killing big cats varied accordingly to attitudinal type (positive and negative). Additionally, acceptability of jaguars and pumas was influenced by existence values, attitudes and park credibility. Human dimensions research helped in understanding the relationship between people and the big cats, highlighting the need, for example, to improve the credibility of the parks in the communities and to decrease the fear of jaguars and pumas.

Models and empirical data for the production of referring expressions

Article Accepted Date: 29 May 2014 Acknowledgements The authors gratefully acknowledge the support of the Cognitive Science Society for the organisation of the Workshop on Production of Referring Expressions: Bridging the Gap between Cognitive and Computational Approaches to Reference, from which this special issue originated. Funding Emiel Krahmer and Albert Gatt thank The Netherlands Organisation for Scientific Research (NWO) for VICI grant Bridging the Gap between Computational Linguistics and Psycholinguistics: The Case of Referring Expressions (grant number 277-70-007).

Work-life Balance and Gender Regime After the Economic Transition

Work-life balance (WLB) is a key issue in our societies in which there is increasing pressure to be permanently available on demand and to work more intensively, and when due to technological change the borders between work and private life appear to be dissolving. However, the social, institutional and normative frames of a region have a huge impact on how people experience work and private life, where the borders between these spheres lie and how much control individuals have in managing these borders. Based on these arguments, this editorial to the special issue Work-life balance/imbalance: individual, organisational and social experiences in Intersections. EEJSP draws attention to the social institutions, frameworks and norms which have an effect on experience, practices and expectations about work-life balance. Concerning the time horizon, this editorial focuses on the change of regime as a reference point since socialist and post-socialist eras differ significantly, although there is still some continuity between them. The authors of this introduction offer an overview of the situation in CEE (Central and Eastern Europe) based mainly on examples of Visegrad countries.

Source apportionment of PM2.5 in Cork Harbour, Ireland using a combination of single particle mass spectrometry and quantitative semi-continuous measurements

An aerosol time-of-flight mass spectrometer (ATOFMS) was deployed for the measurement of the size resolved chemical composition of single particles at a site in Cork Harbour, Ireland for three weeks in August 2008. The ATOFMS was co-located with a suite of semi-continuous instrumentation for the measurement of particle number, elemental carbon (EC), organic carbon (OC), sulfate and particulate matter smaller than 2.5 μm in diameter (PM2.5). The temporality of the ambient ATOFMS particle classes was subsequently used in conjunction with the semi-continuous measurements to apportion PM2.5 mass using positive matrix factorisation. The synergy of the single particle classification procedure and positive matrix factorisation allowed for the identification of six factors, corresponding to vehicular traffic, marine, long-range transport, various combustion, domestic solid fuel combustion and shipping traffic with estimated contributions to the measured PM2.5 mass of 23%, 14%, 13%, 11%, 5% and 1.5% respectively. Shipping traffic was found to contribute 18% of the measured particle number (20–600 nm mobility diameter), and thus may have important implications for human health considering the size and composition of ship exhaust particles. The positive matrix factorisation procedure enabled a more refined interpretation of the single particle results by providing source contributions to PM2.5 mass, while the single particle data enabled the identification of additional factors not possible with typical semi-continuous measurements, including local shipping traffic.

Essays on State-Building and Sectarian Violence

\abstract

This dissertation seeks to explain the role of governmental and non-governmental actors in increasing/reducing the emergence of intergroup conflict after war, when group differences have been a salient aspect of group mobilization. This question emerges from several interrelated branches of scholarship on self-enforcing institutions and power-sharing arrangements, group fragmentation and demographic change, collective mobilization for collectively-targeted violence, and conflict termination and the post-conflict quality of peace. This question is investigated through quantitative analyses performed at the sub-national, national, and cross-national level on the effect of elite competition on the likelihood of violence committed on the basis of group difference after war. These quantitative analyses are each accompanied by qualitative, case study analyses drawn from the American Reconstruction South, Iraq, and Cote d'Ivoire that illustrate and clarify the mechanisms evaluated through quantitative analysis.

Shared findings suggest the correlation of reduced political competition with the increased likelihood of violence committed on the basis of group difference. Separate findings shed light on how covariates related to control over rent extraction and armed forces, decentralization, and citizenship can lead to a reduction in violence. However, these same quantitative analyses and case study analysis suggest that the control of the state can be perceived as a threat after the end of conflict. Further, together these findings suggest the political nature of violence committed on the basis of group difference as opposed to ethnic identity or resource scarcity alone.

Together, these combined analyses shed light on how and why political identities are formed and mobilized for the purpose of committing political violence after war. In this sense, they shed light on the factors that constrain post-conflict violence in deeply divided societies, and contribute to relevant academic, policy, and normative questions.