7 research outputs found
Static and Rotordynamic Analysis of a Plain Annular (Liquid) Seal in the Laminar Regime with a Swirl Brake for Three Clearances
Full text linkThe author conducts tests using a smooth annular seal with a radius of 101.6 mm (4.00 in) with three radial clearances (0.127, 0.254 and 0.381 mm) referred as 1X, 2X and 3X respectively, producing the radial clearance to radius ratios (Cvr/R) of 0.0025,0.005 and 0.0075. The seals have axial length of 45.72 mm (1.80 in), producing the length to diameter ratio of 0.45. ISO VG 46 oil is used as the testing fluid at a temperature range of 46.0-49.0 degrees Celsius to keep fluid flow laminar. A high pre-swirl insert is used to induce high fluid swirl to the swirl brakes (SBs). Each SB comprises of 36 square cuts with an axial depth of 5.08 mm (0.2 in), radial height of 6.35 mm (0.25 in) and circumferential width of 6.35 mm (0.25 in). The author conducts static and dynamic measurements at = 2, 4, 6, 8 krpm, = 2.07, 4.14, 6.21, 8.27 bar (30, 60, 90, 120 psi), and eccentricity ratios, = 0.00, 0.27, 0.53, and 0.80. Static measurements include leakage rate, pre-swirl ratio and outlet swirl ratio, and the static load required to produce the eccentricity ratios.
Dynamic measurements comprise rotor-stator relative displacements, stator acceleration, and applied dynamic load. The measurements are used to calculate stiffness, damping, virtual mass and effective damping coefficients for the seals.
Most importantly, SBs are shown to be effective in minimizing inlet fluid rotation at the 3X clearance but ineffective at the 1X and 2X clearance. When SBs are used with the 3X clearance seal, the cross-coupled stiffness variables have the same sign meaning that the seal would have a WFR of zero and would not produce destabilizing forces on a pump rotor. However, at the 3X clearance, the smooth annular seal has a negative direct stiffness K that could eventually “suck” the rotor into contact with the stator wall, along with dropping the natural frequency of the pump rotor, further reducing its dynamic stability.
Dynamic measurements are compared to predictions based on a model developed by Zirkelback and San Andrés [16]. Most of the predictions agree well with the test data. Notable exceptions are the direct and cross-coupled stiffness coefficients for the 3X clearance. Predictions showed positive direct stiffness and opposite signs for the cross-coupled stiffness coefficients; whereas, the data showed negative direct stiffness and the same positive sign for the cross-coupled stiffness coefficients. Also, for the 1X clearance seal, measured direct damping was higher than predicted at w > 2krpm by about 25%. For the 1X clearance seal, measured cross-coupled damping was lower than predicted by approximately 2-5 times.
At most of the test conditions, measured direct virtual mass coefficients are about 6 times greater than predicted but follow the same general trend. For the 1X and 3X clearance seals, predictions are lower than measured data while predictions match test data well for the 2X clearance seals.
The model predicts the whirl frequency ratio WFR very well for the 1X and 2X clearance seals at all test conditions but fails to predict zero WFR for the 3X clearance se
Express TV: Competing In a Cluttered World of Media for Consumer Preferences and Viewership Patterns
No full textExpress News TV Channel found some reports that their TV channel viewership was declining. In Pakistan, however, the viewership data is managed, still the system is not properly managed and has many loopholes. This can be imagined through the information that one of the most populated area of Karachi, Gulshan Iqbal, TV viewing patterns are evaluated through less than ten people meters. Express news therefore decided to conduct a full survey that included the viewership patterns, the most preferred TV shows, and hosts, morning shows, and anchors. The study revealed interesting facts about the standing of Express News programs and TV viewers’ preferences of the same
Editorial: Mental health characteristics of migrant and local populations in the prevention and management of mental health disorders
Full text linkThis Research Topic endeavors to contribute to the understanding of mental health characteristics among migrant and local populations. The overarching goal is to shed light on the multifaceted nature of migration, exploring its impact on mental wellbeing through assessments and evidence-based interventions. This initiative aims to expand the existing corpus of literature in the field and four key studies form the foundation of this exploration. Migration, a multifaceted and dynamic phenomenon influenced by various factors such as economic conditions, political situations, environmental changes, and individual aspirations, encompasses diverse categories of migrants driven by distinct motives. Economic migrants seek improved financial prospects, while refugees flee persecution, and climate migrants are displaced due to environmental changes. Forced migrants, including internally displaced persons, are compelled to leave their homes within their country, and mixed migration involves a combination of motives . As of 2020, ~281 million people globally had migrated, with 82.4 million being forcibly displaced individuals, including 26.4 million refugees. The mental health of migrants is intricately connected to socioeconomic factors, with poverty, unemployment, discrimination, and other determinants influencing an individual's wellbeing. Housing instability, neighborhood conditions, and access to healthcare services also play roles in mental health outcomes. Social support, derived from community and networks, is crucial for mental wellbeing, while the societal stigma surrounding mental health and cultural norms impact help-seeking behavior. Early life experiences, workplace factors, and access to resources further contribute to mental health disparities. The research by Pham et al. delves into the association between social support and the development of depressive symptoms among storm-affected Vietnamese Americans, recommending prioritization of social support resources in the aftermath of hurricanes.The author(s) declare that no financial support was received for the research, authorship, and/or publication of this article.Scopu
It all starts with structure : investigating learning dynamics in large-scale agile software development
No full textPublisher Copyright: © 2025 The Author(s)Agile software development (ASD) methods have increasingly been used in large-scale software development projects. While ASD emphasizes the importance of social interactions between practitioners for continuous reflection and knowledge sharing, these learning activities become incredibly challenging in large-scale projects. Drawing on well-established theoretical concepts, we posit that learning in large-scale ASD projects requires a suitable environment that empowers practitioners to openly and frequently engage in social interactions, which are essential for reflection and knowledge sharing. We hypothesize that several team-level factors shape individuals’ perceptions about the learning environment and learning activities in their projects, ultimately influencing their learning behavior. To test our model, we collected survey responses from practitioners working in large-scale ASD projects in five Swedish companies (N = 159). The data was analyzed using confirmatory factor analysis (CFA) and structural equation modeling (SEM). The results show that team structure plays a crucial role in promoting team cohesion and reflexivity, which, alongside knowledge sharing, contribute to the learning process. Our study provides ASD development research with a theoretically informed understanding of the interrelationship between the learning environment and learning activities in large-scale ASD. Our results guide practitioners in fostering suitable learning environments and enhancing learning in large-scale ASD.Peer reviewe
Complex networks analysis of manual and machine translations
No full textComplex networks have been increasingly used in text analysis, including in connection with natural language processing tools, as important text features appear to be captured by the topology and dynamics of the networks. Following previous works that apply complex networks concepts to text quality measurement, summary evaluation, and author characterization, we now focus on machine translation (MT). In this paper we assess the possible representation of texts as complex networks to evaluate cross-linguistic issues inherent in manual and machine translation. We show that different quality translations generated by NIT tools can be distinguished from their manual counterparts by means of metrics such as in-(ID) and out-degrees (OD), clustering coefficient (CC), and shortest paths (SP). For instance, we demonstrate that the average OD in networks of automatic translations consistently exceeds the values obtained for manual ones, and that the CC values of source texts are not preserved for manual translations, but are for good automatic translations. This probably reflects the text rearrangements humans perform during manual translation. We envisage that such findings could lead to better NIT tools and automatic evaluation metrics
Express TV: Competing In a Cluttered World of Media for Consumer Preferences and Viewership Patterns
Full text linkExpress News TV Channel found some reports that their TV channel viewership was declining. In Pakistan, however, the viewership data is managed, still the system is not properly managed and has many loopholes. This can be imagined through the information that one of the most populated area of Karachi, Gulshan Iqbal, TV viewing patterns are evaluated through less than ten people meters. Express news therefore decided to conduct a full survey that included the viewership patterns, the most preferred TV shows, and hosts, morning shows, and anchors. The study revealed interesting facts about the standing of Express News programs and TV viewers’ preferences of the same
Gestão empresarial do talento humano a partir da política de responsabilidade social. Uma revisão sistemática
No full textCorporate social responsibility is a policy framed in the ethics of good competitive and productive practices of organizations operating in diverse socio-cultural and global economic environments. Objective. To assess the efficiency of administrative actions related to human talent management in various work environments within the business sector. Methodology. The research methodology consists of a descriptive analysis of the subject derived from the systematic review of scientific evidence from specialized literature and integrates the PRISMA procedure into this process. Results. The findings demonstrate the significance of strategically aligning personnel with the mission objectives of organizations. The incorporation and implementation of social and labor rights within the labor welfare subsystems is highlighted, alongside the promotion of healthy work environments and financial investments. Conclusions. The study’s findings identify critical success factors for effective personnel management based on sustainable knowledge management, including compensation, mentoring, and training processes, as well as the promotion of individuals’ human and social capital.La responsabilidad social empresarial es una política enmarcada en la ética de las buenas prácticas competitivas y productivas de las organizaciones en los diferentes entornos socioculturales y económicos globales. Objetivo. Analizar la eficiencia de las actividades administrativas de la gestión del talento humano del sector empresarial en los diversos contextos laborales. Metodología. La metodología de esta investigación corresponde a un análisis descriptivo de la temática con base en la revisión sistemática de evidencia científica de literatura especializada, integrándose el procedimiento PRISMA a este proceso. Resultados. Los resultados muestran la importancia de alinear estratégicamente al personal con los objetivos misionales de las empresas. Se enfatiza en la integración y práctica de los derechos sociales y laborales en los subsistemas de bienestar laboral, los entornos laborales saludables y la inversión financiera. Conclusiones. Las conclusiones del estudio señalan elementos clave de éxito para una gestión del personal eficaz con base en la gestión del conocimiento sostenible en función de los procesos de compensación, capacitación y entrenamiento, así como la promoción del capital humano y social de las personas.A responsabilidade social corporativa é uma política enquadrada na ética das boas práticas competitivas e produtivas das organizações em diferentes ambientes socioculturais e económicos globais. Objetivo. Analisar a eficiência das atividades administrativas de gestão de talentos humanos no setor empresarial em diversos contextos de trabalho. Metodologia. A metodologia desta investigação corresponde a uma análise descritiva do tema baseada na revisão sistemática de evidências científicas da literatura especializada, integrando neste processo o procedimento PRISMA. Resultados. Os resultados mostram a importância de alinhar estrategicamente o pessoal com os objetivos missionais das empresas. A ênfase é colocada na integração e prática dos direitos sociais e laborais nos subsistemas de bem-estar laboral, ambientes de trabalho saudáveis e investimento financeiro. Conclusões. As conclusões do estudo apontam elementos-chave de sucesso para uma gestão de pessoas eficaz baseada na gestão sustentável do conhecimento baseada em processos de remuneração, formação e coaching, bem como na promoção do capital humano e social das pessoa
