Transitional Model Research Articles

Pair Unit-Cell Model in the Weak 1st-Order Phase Transition

Pair Unit-Cell Model in the Weak 1st-Order Phase Transition

Chemical profiling, toxicity assessment, anti-diarrhoeal, anti-inflammatory and antinociceptive activities of Canarium schweinfurthii Engl. (Burseraceae) bark in rats

Ethnopharmacological relevanceThe bark of Canarium schweinfurthii is used in ethnomedicine for the treatment of diabetes, pain, malaria, fever and diarrhoea. Aim of the studyThe chemical phytoconstituents, antidiarrheal, anti-inflammatory and antinociceptive effects and safety profile of the aqueous extract of Canarium schweinfurthii bark (AECSB) were investigated. Materials and methodsGas chromatography-mass spectrometry (GC-MS) was used to analyse the phytochemical composition. In the acute toxicity test, AECSB were administered up to 2 g/kg by oral gavage. For the subacute toxicity test (28 days), rats in group 1 (control) received no AECSB, while rats in groups 2–4 were administered different doses of AECSB. Charcoal meal transit and castor oil-induced diarrhoea models were used to study the antidiarrheal effect, while egg albumin/carrageenan and acetic acid/tail immersion models were used for the anti-inflammatory and antinociceptive studies, respectively. With the exception of the acute toxicity experiment, AECSB was administered orally at doses of 200, 400 and 800 mg/kg. ResultsBioactive phytoconstituents identified include p-cymene, δ-terpinene, linalool and phytol. No adverse effects or mortality were observed in acute and subacute studies. Treatment with AECSB (28 days) had no significant effect on organ weight, biochemical, hematologic and histopathologic parameters compared to the control groups (p > 0.05). Comparable antidiarrheal and antinociceptive effects were observed in both AECSB- and standard drug-treated groups, while the 400 and 800 mg/kg AECSB-treated groups showed remarkable anti-inflammatory effects compared to the standard drug-treated and control groups (p < 0.05). ConclusionAECSB has antidiarrheal, antinociceptive and anti-inflammatory effects and can be safely used for therapeutic purposes.

The role of business models in the sustainable transition of shared mobility services in China and South Korea

ABSTRACT The evolution of shared mobility services in Asia is evident in their distinct adoption patterns, when examining the business models (BMs) in China and South Korea. Employing a research framework that delineates transition pathways into three phases, we trace the trajectory of shared mobility services in contrasting socio-technical systems, by a ground theory approach. Our study reveals the transformation of imitated BMs into refined and localized forms as niche innovations interact with the regime. Highlighting the pivotal role of BMs, our findings underscore their capacity to navigate diverse institutions and socio-political debates, facilitating the sustainable transition of shared mobility services.

Natural History of Nonmetastatic Prostate Cancer Managed With Watchful Waiting

It is uncertain to what extent watchful waiting (WW) in men with nonmetastatic prostate cancer (PCa) and a life expectancy of less than 10 years is associated with adverse consequences. To report transitions to androgen deprivation therapy (ADT), castration-resistant prostate cancer (CRPC), death from PCa, or death from other causes in men treated with a WW strategy. This nationwide, population-based cohort study included men with nonmetastatic PCa diagnosed since 2007 and registered in the National Prostate Cancer Register of Sweden with WW as the primary treatment strategy and with life expectancy less than 10 years. Life expectancy was calculated based on age, the Charlson Comorbidity Index (CCI), and a drug comorbidity index. Observed state transition models complemented observed data to extend follow-up to more than 20 years. Analyses were performed between 2022 and 2023. Nonmetastatic PCa. Transitions to ADT, CRPC, death from PCa, and death from other causes were measured using state transition modeling. The sample included 5234 men (median [IQR] age at diagnosis, 81 [79-84] years). After 5 years, 954 men with low-risk PCa (66.2%) and 740 with high-risk PCa (36.1%) were still alive and not receiving ADT. At 10 years, the corresponding proportions were 25.5% (n = 367) and 10.4% (n = 213), respectively. After 10 years, 59 men with low-risk PCa (4.1%) and 221 with high-risk PCa (10.8%) had transitioned to CRPC. Ten years after diagnosis, 1330 deaths in the low-risk group (92.3%) and 1724 in the high-risk group (84.1%) were from causes other than PCa. These findings suggest that the WW management strategy is appropriate for minimizing adverse consequences of PCa in men with a baseline life expectancy of less than 10 years.

Transitional flow in a two-stage low-pressure axial turbine under different clocking of blades

Different modes of transitional flows are numerically analyzed in a two-stage low-pressure axial turbine, while being exposed to various clocking of second stator blades and results are presented in this paper. The numerical method utilizes coupled approach of SST k-ω turbulence andγ−Re˜θt transitional models. Kinematic of the wake flow in the blades passage and flow topology are presented and discussed. Different types of transitional flows including “separation induced transition” (i.e., “laminar separation bubble”), “reverse transition” and “bypass transition” are distinguished. Results of surface distribution of pressure and skin friction coefficients, turbulence intensity, intermittency and also transition momentum thickness Reynolds number are presented for the worst and optimum clocking cases, in detail. Results show that the onset points of separation induced transition and bypass transition move upstream by 6.64% and 5.47% in the optimum clocking in comparison to the worst case, respectively. In the optimum clocking the separation bubble length decreases by 1.57% and the onset point of the reverse transition moves downstream by 1.2%. All these beneficial effects happen basically as a result of impinging the first stage wake flow on the leading edge of the second stator blade suction side, which in turn, causes transition from laminar to turbulent to occur within the boundary layer.

Numerical investigation of vortex-induced forces on a wind turbine tower segment at very high Reynolds numbers

The vortex-induced forces on an extruded cylinder with a span of two diameters representative of a finite segment of a non-tapered wind turbine tower at a very high Reynolds number (Re = 8.0×106) are numerically investigated using an incompressible Navier-Stokes flow solver with an Improved Delayed Detached Eddy Simulation (IDDES) turbulence model and correlation-based boundary layer transition modelling. The solution shows spanwise correlated structured vortex shedding with the Strouhal number St = 0.48. The boundary layer transition is found to occur at θ transition = 70 ◦ , and boundary layer separation is found to occur at θ separation = 120 ◦ . Results from the grid dependency study strongly imply that when using IDDES, the Strouhal number converges to higher values than previously reported by the literature as the grid is refined, with results ranging from St ∼ 0.44 using a grid with 4.2 × 106 cells, to St = 0.48 for the finest considered grid with 33 × 106 cells. This behaviour is not seen for URANS, where St = 0.33 for the finest grid.

Anomaly Detection in SCADA Systems: A State Transition Modeling

Anomaly Detection in SCADA Systems: A State Transition Modeling

Surface modeling of wettability transition on α-quartz: Insights from experiments and molecular dynamics simulations

The wettability of quartz surfaces is a critical property in numerous energy-related industrial processes. However, accurately quantifying wettability is challenging due to the multitude of factors that can influence wetting behavior. Herein, we proposed a generalized surface modeling procedure addressing microscopic insights to calculate the contact angles of liquids on quartz under different scenarios. An optical goniometer experimentally measured the contact angles and validated the proposed surface modeling procedure. The effects of surface density of hydroxyl groups, temperature, surfactants, and crude oil composition on the wettability of quartz surfaces were studied. The results revealed that an increased hydroxyl group density significantly improved water wettability on a quartz surface. An increased temperature reduced the water contact angle on quartz, and such decreasing rates became steeper at high temperatures. The surfactants’ adsorption morphology determined the wettability of a quartz surface. Moreover, the polar components in crude oil significantly increased the hydrophobicity of a quartz surface, making it easier to adsorb more oil molecules to alter the quartz wettability further. The valuable outcomes of this paper contribute to understanding the complex quartz wettability and pave the way for further studies involving quartz surface modeling.

Experiencing death and grief at the border: a sociocultural psychological analysis of activists’ struggles at the European and Central-American border

ABSTRACT Dramatic consequences related to borders, such as migrants' deaths, disappearances and human rights violations, have increased since the 1990s. Several migration policies contribute to border violence, leading to traumatic mental health effects on migrants, their families and activists. The literature has overlooked the psychological, cultural and religious/spiritual experience of activists sharing the burden of migrants and their families' grief and struggles. To explore the experiences of activists while in the act, the research adopted a sociocultural approach and conducted twenty-five semi-structured interviews with border activists. The qualitative thematic analysis revealed five themes, encompassing how activists dynamically make sense of their experiences: rehumanising vocation; endless feelings; empathic-epistemic experiential ambivalence; personal coping strategies and liberation transformative actions. These themes offer a transitional model, progressing from acknowledging States' responsibilities to developing transnational, cross-cultural and inter-faith forms of human solidarity. Finally, this model fuels ethically inspired community struggles towards social equality, justice and transformation.

Eliminate Structural Injustices or Perpetuate Them: Indigenous Peoples and Transitional Justice in the Criminal Court System of Taiwan

ABSTRACT∞ In 2017, Taiwan’s government proposed reforms to the Indigenous Specialized Criminal Court (ISC) within its criminal court system (court system). Situated within the contemporary theoretical framework of transitional justice, this article explores the theoretical significance of these reforms and examines their actual state of implementation. Firstly, the article points out that the court system has led to structural injustices like the erasure of culture and socio-economic disadvantages for indigenous peoples, highlighting the limitations of the conventional transitional justice model in addressing these injustices. As a response, the ISC reform adopts strategies that differ from the conventional model. The article then attempts to develop an enhanced transitional justice model that includes structural injustices within its scope and explains the ISC reform initiatives and their inherent transitional justice significance. Finally, by evaluating the implementation status of the ISC reform, the article elucidates its theoretical implications and the feedback it offers to contemporary theoretical debates.

Improved Prediction of the Flow in Cylindrical Critical Flow Venturi Nozzles Using a Transitional Model

Critical flow Venturi nozzles (CFVNs) are a state-of-the-art secondary standard widely used for gas flow measurements with high precision. The flow rate correlates with the type and thickness of the boundary layer (BL) inside the nozzle throat. In the cylindrical type—one of the two standard designs of CFVNs—the nozzle throat encompasses a defined axial length in which the BL develops. This numerical study is concerned with the BL effects in a cylindrical CFVN by means of two turbulence models. Compared to experimental data, the k-ω\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\omega$$\\end{document} SST model predicts the discharge coefficient well for high and low Reynolds numbers, but not in the intermediate regime. The γ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\gamma$$\\end{document}-Reθ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$Re_{\ heta }$$\\end{document} model, on the contrary, agrees well with experimental data in the entire flow range. Relevant quantities and profiles of the BL are separately investigated in the laminar, turbulent, and transitional region. The calculated laminar and turbulent BL thicknesses correspond to predictions based on integral methods for solving the BL equations. Simple representations are proposed for the Zagarola-Smits scaled laminar and turbulent deficit BL profiles removing the effects of axial position, Reynolds number, and pressure gradient. Furthermore, the shape factor is investigated as a characteristic parameter for determining the transitional region.

Al-Jazeera Arabic and Al-Jazeera English headlines on the Russian-Ukrainian conflict: a Hallidayan transitivity analysis

ABSTRACT Research in communication studies has suggested that Al-Jazeera produces different versions of news stories for different audiences. Yet, examining the linguistic means used to create these versions has remained under-researched. Drawing on Fairclough’s three-dimensional model (1992) and Halliday’s transitivity model (1985), this study aims at exploring how Al-Jazeera Arabic (AJA) and Al-Jazeera English (AJE) discursively represented the participants involved in the 2022 Russo-Ukrainian conflict in headlines. The analysis of transitivity patterns in AJA and AJE headlines reveals both similar and different representations of the conflict. Although they avoided negative labeling of the Russian government, both channels ascribed conflict escalation to it, highlighting civilians suffering and protesting. Nevertheless, while AJE emphasized the Ukrainian government vulnerability, AJA presented the conflict as a confrontation between two symmetrical forces. Similarities are attributed to organizational and social institutional forces, while differences result from different editorial policies and audience preferences. As discursive and social practices, the headlines contribute to shaping audience perceptions of the conflict, with AJA challenging the prevailing western narrative of the conflict while AJE reinforcing it.

Adopting Transitional Business Models in Small Fitness Businesses in Response to Business Disruptions

Adopting Transitional Business Models in Small Fitness Businesses in Response to Business Disruptions

Pilot Process Evaluation of the Supporting Older Adults at Risk Model: A RE-AIM Approach.

Despite evidence supporting transitional care models, hospitals report challenges implementing and sustaining them. The Discharge to Assess (D2A) Model is an innovative solution to this problem but required translation from a national health system context to an U.S.-based context. We translated the central tenets of the D2A model to establish the Supporting Older Adults at Risk (SOAR) Model, which unfolds in three phases: Prepare, Transition, and Support. The purpose of this project was to conduct a process evaluation of the SOAR Model in practice using the RE-AIM Framework (Reach, Effectiveness, Adoption, Implementation, and Maintenance). Forty patients completed all SOAR Model components for a Reach of 21%. Patients averaged 80 years of age, 53% were female, and 64% Black/AA. SOAR significantly improved discharge before noon, time to first home visit, and use of the in-house pharmacy. SOAR also improved length of hospital stay, emergency department visits, and readmissions. Twenty-one of the 26 Implementation measures unfolded with 75% or greater fidelity. Sixteen of the 24 Adoption measures unfolded with 75% or greater fidelity. COVID-19 limited Maintenance. Given the model unfolds across settings over time, requiring adoption from interprofessional team members, patients, and families, future work should focus on improving reach and adoption.

Choose your own story: creative non-fiction about athletes attempting to qualify for the Olympics

ABSTRACT The Olympics qualification phase is a taxing process for elite athletes, and despite the fact that most do not achieve their goal of qualifying for the Olympics, little is known about how they make meaning from non-qualification. This longitudinal qualitative study describes the stories of athletes preparing for the Tokyo 2020 Olympic Games in the context of the COVID-19 pandemic and interprets the athletes’ meaning-making of their story of non-qualification. We conducted semi-structured interviews with seven elite athletes (a) during the COVID-19 lockdown, (b) after the COVID-19 lockdown, (c) pre-Tokyo, and (d) post-Tokyo. Results of a thematic narrative analysis are presented through creative non-fiction in the format of the ‘Choose your own story’ genre. Two main narratives are presented: a ‘terminal’ narrative, reflecting stories acknowledging the end of an unmade journey with no possibility of a future opportunity, and a ‘maybe next time’ narrative, reflecting stories that acknowledge the lost opportunity while still contemplating the possibility of future qualification. This study extends previous research by providing a deeper understanding of non-event transitions and proposing a review of existing transitional models in sports. We challenge the belief that not reaching a goal constitutes failure and propose alternative narratives. Lastly, we use the innovative ‘Choose your own story’ representation format to increase the impact of our findings on non-academic audiences.

Transitional justice interventions in Sri Lanka: why do they keep failing?

ABSTRACT How can a country meaningfully commit to transitional justice interventions when ethnocracy and majoritarianism remain deeply entrenched in its political, legal and constitutional structures? Despite the creation of several commissions of inquiry and other mechanisms over the years to deal with the past, including those set up during the civil war, transitional justice and reconciliation have not been an integral part of Sri Lanka’s nation-building campaign and socio-cultural consciousness. Sri Lanka’s transitional justice interventions have historically been top-down, state-driven and elitist that lacked wider consultations with various groups and take their interests and demands into account. The oscillation between different political parties and their domestic and foreign policy orientations have had little impact. This article argues that the top-down and ‘one-size-fits-all’ transitional justice model does not work in certain societies, including Sri Lanka, and a shift to a unique and contexualised approach is imperative not only for longer-term sustainability but also to allow voices from the ground to be heard and included. This paper critiques the dominant transitional justice process and examines the challenges of achieving transitional justice in deeply divided societies where majoritarianism strengthens after the end of a violent conflict. Nonetheless, it acknowledges the risks of over-eulogising the bottom-up and local approach.

Self-starting and performance improvement of a Darrieus type wind turbine using the plasma actuator

Although the popularity of Darrieus-type vertical axis wind turbines is growing for small-scale electricity generation, these turbines have severe challenges in self-starting. This paper proposes a flow control method, namely, the plasma actuator, to solve the self-starting problem besides enhancing the turbine performance. The Darrieus turbine is numerically investigated using a pressure-based finite volume method to solve the unsteady Reynolds-averaged Navier–Stokes and the γ–Reθt transitional model equations. Simulation of the blade rotation is performed using the sliding mesh technique accompanied by the turbine equation of motion to enable the blade rotational degree of freedom. Furthermore, the body forces associated with the plasma actuator are determined by calibrating the Shyy plasma model parameters. The plasma actuator is assessed at both the constant and free rotational speeds. The constant rotational speed results in plasma off condition show negative torque generation for tip speed ratios lower than 1.5, known as the origin of turbine self-starting challenges. The plasma actuator improves the negative torque by 128% in the tip speed ratio of 0.5 and turns it positive. Also, at larger tip speed ratios, it reduces the negative torque generation and enhances the turbine power production by up to 260%. Furthermore, the plasma actuator in free rotational speed improves the tip speed ratio increment by up to 8%, reducing the total time of turbine self-starting.

Cost-Effectiveness Analysis of Triptorelin, Goserelin, and Leuprolide in the Treatment of Patients With Metastatic Prostate Cancer: A Societal Perspective

ObjectivesMetastatic prostate cancer is the most common malignant cancer and the second leading cause of death due to various types of cancer among men after lung cancer. This study aimed to analyze the cost-effectiveness of triptorelin, goserelin, and leuprolide in the treatment of the patients with metastatic prostate cancer from the societal perspective in Iran in 2020. MethodsThis is a cost-effectiveness study in which a 20-year Markov transition modeling was applied. In this study, local cost and quality-of-life data of each health state were gathered from cohort of patients. The TreeAge pro 2020 and Microsoft Excel 2016 software were used to simulate cost-effectiveness of each treatment in the long term. The one-way and probabilistic sensitivity analyses were also performed to measure robustness of the model outputs. ResultsThe findings indicated that the mean costs and utility gained over a 20-year horizon for goserelin, triptorelin, and leuprolide treatments were $ 13 539.13 and 6.365 quality-adjusted life-years (QALY), $ 18 124.75 and 6.658 QALY, and $ 26 006.92 and 6.856 QALY, respectively. Goserelin was considered as a superior treatment option, given the estimated incremental cost-effectiveness ratio. The one-way and probabilistic sensitivity analyses confirmed the robustness of the study outcomes. ConclusionsAccording to the results of the present study, goserelin was the most effective and cost-effective strategy versus 2 other options. It could be recommended to policy makers of the Iran healthcare system to prioritize it in clinical guidelines and reimbursement policies.

Computational Fluid Dynamics Prediction of External Thermal Loads on Film-Cooled Gas Turbine Vanes: A Validation of Reynolds-Averaged Navier–Stokes Transition Models and Scale-Resolving Simulations for the VKI LS-94 Test Case

Given the increasing role of computational fluid dynamics (CFD) simulations in the aerothermal design of gas turbine vanes and blades, their rigorous validation is becoming more and more important. This article exploits an experimental database obtained by the von Karman Institute (VKI) for Fluid Dynamics for the LS-94 test case. This represents a film-cooled transonic turbine vane, investigated in a five-vane linear cascade configuration under engine-like conditions in terms of the Reynolds number and Mach number. The experimental characterization included inlet freestream turbulence measured with hot-wire anemometry, aerodynamic performance assessed with a three-hole pressure probe in the downstream section, and vane convective heat transfer coefficient distribution determined with thin-film thermometers. The test matrix included cases without any film-cooling injection, pressure-side injection, and suction-side injection. The CFD simulations were carried out in Ansys Fluent, considering the impact of mesh sizing and steady-state Reynolds-Averaged Navier-Stokes (RANS) transition modelling, as well as more accurate transient scale-resolving simulations. This work provides insight into the advantages and drawbacks of such approaches for gas turbine hot-gas path designers.

Computable turbulence modeling of laminar-turbulent transition characterized boundary layer flows with the aid of artificial neural network

The continuous development of machine learning algorithms has stimulated the technological revolution on turbulence modeling for Reynolds-averaged Navier–Stokes (RANS) simulations. In this paper, a computable transition-enabled turbulence model is developed with the aid of an artificial neural network (ANN), which maps the relation between the mean flow variables from the shear stress transport (SST) model on coarse grid and the turbulent viscosity from SST-γ model on fine grid. It turns out that the ANN model can predict the aerodynamic integral quantities, transition onset location, laminar separation bubble structure, streamwise velocity distribution, etc. with superior accuracy and robustness for subsonic and moderate transonic airfoil flows. Meanwhile, the ANN model can significantly improve the convergence property with a much higher convergence speed of the model equation in comparison with traditional transition-enabled RANS model. Moreover, due to the lack of solving RANS model equations and use of grid interpolation technology, the computation speed of this ANN model is improved by a factor of about six over the conventional benchmark model. Therefore, the present computable ANN model provides a new perspective for high-efficiency simulation of transition-characterized flows in engineering applications.