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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.

Numerical investigation on the use of multi-element blades in vertical-axis wind turbines

Bah, Elhadji Alpha Amadou 08 June 2015 (has links)
The interest in sustainable forms of energy is being driven by the anticipated scarcity of traditional fossil fuels over the coming decades. There is also a growing concern about the effects of fossil fuel emissions on human health and the environment. Many sources of renewable energy are being researched and implemented for power production. In particular, wind power generation by horizontal- and vertical-axis wind turbines is very popular. Vertical-axis wind turbines (VAWTs) have a relative construction simplicity compared to horizontal-axis wind turbines (HAWTs). However, VAWTs present specific challenges that may hinder their performance. For instance, they are strongly affected by dynamic stall. A significant part of the kinetic energy contained in the oncoming wind is lost in swirl and vortices. As a result, VAWTs have lower power production compared to HAWTs. First, the present work is aimed at the study of the aerodynamics of straight-bladed VAWTs (SB-VAWTs). Empirical calculations are conducted in a preliminary work. Then a two-dimensional double multiple streamtube (DMST) approach supported by a two-dimensional numerical study is implemented. The dynamic stall and aerodynamic performance of the rotor are investigated. A VAWT-fitted dynamic stall model is implemented. Computational fluid dynamics (CFD) simulations are conducted to serve as reference for the DMST calculations. This three-pronged approach allows us to efficiently explore multiple configurations. The dynamic stall phenomenon is identified as a primary cause of performance loss. The results in this section validate the DMST model as a good replacement for CFD analysis in early phase design provided that a good dynamic stall model is used. After having identify the primary cause of performance loss, the goal is to investigate the use to dual-element blades for alleviating the effect of dynamic stall, thereby improving the performance of the rotor. The desirable airfoil characteristics are defined and a parametric analysis conducted. In the present study the parameters consists of the size of the blade elements, the space between them, and their relative orientation. The performance of the rotor is calculated and compared to the baseline. The results highlight the preeminence of the two-element configuration over the single-element provided that the adequate parametric study is conducted beforehand. A performance enhancement is obtained over a large range of tip speed ratios. The starting characteristics and the operation stability are also improved. Finally, an economic analysis is conducted to determine the cost of energy and thus the financial viability of such a project. The Great Coast of Senegal is selected as site of operation. The energy need and sources of this region are presented along with its wind energy potential. The cost evaluation shows the economic viability by comparing the cost of energy to the current energy market prices.

Experiences, Challenges, and Resiliency Among Survivors of Domestic Minor Sex Trafficking

Deermer, Coleen 01 June 2016 (has links)
This qualitative study sought to explore the personal experiences of those who have been victims of Domestic Minor Sex Trafficking (DMST), the challenges they faced as they transitioned into survivors, and the factors they attributed to their resiliency. DMST victims are among the marginalized populations enduring social injustices within our communities. Social workers seek to serve these individuals, and yet they are just one part of the system of helping professionals that will encounter these victims. The interactions that DMST victims have with each entity of the system makes a difference in the recovery process as they become a survivor. Much of the research that had previously been conducted focused on the therapist’s perspective of DMST as experienced through their own therapeutic relationships with the victims. In contrast, the primary goal of this research was to focus on the perspective of those who had been victims of DMST so those in the helping professions can more effectively help these individuals. In order to achieve such goals it is essential to build a foundation of knowledge. This involves providing educational aspects to understand the scope of the problem and the dynamics of the trafficking relationship. In the case of this research, the victims themselves provide the knowledge that was gained through their participation. In addition, the research participants were able to express their perspective of both effective and ineffective aspects of their recovery, as well as what modifications could be made to improve the experiences of those who have been DMST victims in the process of becoming a survivor. Despite the differences in the experiences of the participants, this research revealed major themes in terms of dysfunctional family dynamics in childhood, a lack of recognition of the signs of trafficking, a lack of appropriate recovery services, and provided insight into helpful strategies that could be implemented to improve the process as these individuals transition from victim to survivor. The personal experiences within the specific themes and categories provide beneficial knowledge for those involved in the helping professions as they encounter victims of DMST.

Practitioners Views on Effective Interventions for Victims of Domestic Minor Sex Trafficking

Nibo, Tracy 01 June 2016 (has links)
ABSTRACT The purpose of the present study was to explore methods of effective treatment interventions for victims of Domestic Minor Sex Trafficking (DMST) from the viewpoint of practitioners. Although risk factors are present the secretive nature of the DMST population make victims difficult to identify. The sensitivity of the trauma victims experience also make it difficult to determine effective interventions to utilize for treatment of this population. This study seeks to gain the perspectives of practitioners who work with the DMST population in order to overcome these barriers. This study utilizes a qualitative design in which 10 practitioners were interviewed to determine effective methods of intervention. In doing so risk factors for identification, psychological impact of victimization and various interventions were highlighted to determine the most frequently used and most effective methods of intervention. Findings of the study indicate sexual abuse, homelessness, vulnerability, physical abuse and neglect as risk factors directly related to victimization. Findings of the study also indicate CBT, trauma focused and interpersonal psychotherapy as effective methods of intervention. The implementation of training programs specifically tailored to the DMST population is a necessary solution to bring awareness to DMST, assist in the identification of risk factors to prevent victimization and identify effective interventions for victims.


Baca, Adriana Lopez, Lopez, Melissa Marie 01 June 2016 (has links)
Domestic minor sex trafficking (DMST) is a significant issue that affects children, families, and communities throughout the United States. Due to the illegal nature of the problem, it is difficult for law enforcement to identify victims of DMST and when they are identified it is challenging to provide them with services. Because law enforcement often encounter DMST victims through first response calls or within juvenile hall, it is important to understand the collaboration efforts between social workers and law enforcement in order to provide effective services for this population. Therefore, the purpose of this study is to gain an understanding of the perceptions of law enforcement officers regarding the involvement of social workers in DMST cases. This study used a qualitative design by collecting data through face-to-face interviews with 10 law enforcement officers from Los Angeles County and San Bernardino County. This design allowed participants the opportunity to provide a more in-depth explanation regarding the involvement of social workers in DMST cases. The study found that there is a need for social workers to collaborate with law enforcement agencies to provide and advocate for services for victims of DMST. The study also indicated the need for transitional housing or other placement options for youth because the current alternative is incarceration.

Domestic Minor Sex Trafficking and Social Work Practice

Chester, Stephanie E. 01 January 2017 (has links)
Domestic minor sex trafficking (DMST) is a social problem affecting children between the ages of 12 and 17 years old. The issues related to DMST present challenges for social work practitioners because they often lack knowledge regarding how to identify and provide specialized services to this population. The purpose of the qualitative study was to collect and analyze data to develop an understanding of how social workers in the northeastern region of the United States identified challenges and thereby improved their practice skills when intervening with this vulnerable population. An epistemological paradigm, with a constructivist perspective employing Nguyen's systems theory, was used to understand the phenomena. The practice-focused research question posed to 5 clinically licensed social workers (LCSW) asked about the perceived barriers hindering social work practice when identifying victims of DMST. In addition, upon recognition of DMST victims, participants described existing community services that addressed their social work practice needs. The LCSWs attended 3 hour-long audio-recorded focus groups, offering their knowledge and experiences related to DMST in the designated region. Constant comparison was used to analyze the data provided by the participants during the focus groups. The key findings indicated a lack of proper identification tools and specialized services for this community. Findings can be used to recommend social change efforts, which included increasing communication about the victims between jurisdictions and communications with policy makers and service providers regarding the need to develop and implement training on various related topics.

Cal State San Bernardino Social Work Students' Attitudes Toward Domestic Minor Sex-Trafficked (DMST) Youth

Marinelli, Crystal Lorraine, Hunt, Andrea Sara 01 June 2017 (has links)
Domestic Minor Sex Trafficking (DMST) affects hundreds of thousands of youth every year. In the past, DMST youth were often viewed by law enforcement and the criminal justice system as "offenders" and were usually arrested for solicitation even though they were minors. While new laws have begun to identify youth as victims, it has not yet been ensured that social workers have adopted this perspective. This quantitative study's purpose was to examine Cal State University San Bernardino (CSUSB) Bachelor of Social Work (BASW) and Master of Social Work (MSW) students' attitudes toward DMST youth. Participants completed an online questionnaire using Qualtrics software. Data were analyzed using SPSS version 21, using statistical tests including frequencies, Pearson's R, and ANOVA. The hypothesis that knowledge, exposure to curriculum, and past experiences impacted students' stigmatization of DMST youth was not supported by the data. Instead, results indicated that CSUSB social work students did not stigmatize the DMST population. Because these findings cannot be generalized to social workers in the field, future research should explore whether social workers currently working with DMST youth stigmatize this population. These findings also have implications for the CSUSB School of Social Work as they revealed that some students lacked education about this population and, consequently, felt unprepared to work with this population.

Identifying and Mitigating Domestic Minor Sex Trafficking in an Urban Community

Gresham, Anne Ellen 01 January 2015 (has links)
Human trafficking, domestic minor sex trafficking (DMST), and commercial sexual exploitation of children (CSEC) are complex and multifaceted occurrences in the United States. As the numbers of youth ensnared in sexually exploitive situations increase, organizations and communities are called upon to address the ramifications of this abuse; little research was located, however, that examined collaborative networks and partnerships that address victim identification and mitigation of DMST and CSEC. The purpose of this qualitative single case study was to determine whether strategic partnerships existed within the community under investigation. The theoretical framework was environmental theory, as first described by Florence Nightingale; the conceptual framework was centered on collaborative networks. Research questions focused on victim identification and organizational strategies for collaboration and mitigation of sex trafficking. The research population was composed of 8 individuals working in organizations in a metropolitan area on the West Coast that served victims of DMST and CSEC. Data obtained from interviews were coded, compared, and analyzed for major and emergent themes. Findings indicated that, in the effort to identify victims, these 8 individuals needed to consider all children involved in prostitution as victims and not criminals. Further, their efforts toward mitigation needed to center on widespread education across the broader social spectrum of the issues with DMST and CSEC. These workers identified strategies identified to address DMST and CSEC included the "5 Ps": prevention, protection, prosecution, partnership, and policy. These findings may inform organizations and policy makers about how to make informed decisions about the needs and challenges of addressing sexually exploited youth.


Campbell, Cristin Elizabeth 01 June 2018 (has links)
Domestic Minor Sex Trafficking is a crime happening right in our own backyards. Social Workers are seeing this vulnerable population fall through the fingers of social services and into the clutches of traffickers at alarming rates. This research project analyzed San Bernardino and Riverside County Foster Family Agency Social Workers' Awareness of Domestic Minor Sex Trafficking. This project was a quantitative exploratory research design. A paper survey was distributed to Foster Family Agency Social Workers within San Bernardino and Riverside County, California using a snowball sampling. A bivariate analysis was conducted to evaluate the relationship that social work experience in the field and the amount of DMST trainings attended have on social work awareness of DMST. The results of this research show that high number of DMST trainings result in a lower level of DMST awareness. Data also showed no significant relationship between how participants scored on the Awareness of Domestic Minor Sex Trafficking survey and years of social work experience. The results of this research can be used as a baseline to study Foster Family Agency Social Worker awareness with San Bernardino and Riverside County, California and how to best implement effective DMST trainings; as federal and state laws are predicted to make Domestic Minor Sex Trafficking training mandatory within social service fields.

Design and Experimentation of Darrieus Vertical Axis Wind Turbines

Gonzalez Campos, Jose Alberto 07 September 2020 (has links)
No description available.

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