Optimization of a horizontal axis marine current turbine via surrogate models

Thandayutham, Karthikeyan,Avital, E.J.,Venkatesan, Nithya,Samad, Abdus Techno-Press 2019 Ocean systems engineering Vol.9 No.2

Flow through a scaled horizontal axis marine current turbine was numerically simulated after validation and the turbine design was optimized. The computational fluid dynamics (CFD) code Ansys-CFX 16.1 for numerical modeling, an in-house blade element momentum (BEM) code for analytical modeling and an in-house surrogate-based optimization (SBO) code were used to find an optimal turbine design. The blade-pitch angle (${\theta}$) and the number of rotor blades (NR) were taken as design variables. A single objective optimization approach was utilized in the present work. The defined objective function was the turbine's power coefficient ($C_P$). A $3{\times}3$ full-factorial sampling technique was used to define the sample space. This sampling technique gave different turbine designs, which were further evaluated for the objective function by solving the Reynolds-Averaged Navier-Stokes equations (RANS). Finally, the SBO technique with search algorithm produced an optimal design. It is found that the optimal design has improved the objective function by 26.5%. This article presents the solution approach, analysis of the turbine flow field and the predictability of various surrogate based techniques.

Bridging the Gap between Philosophy and Psychotherapy: An Outline for the Integration of Philosophical Counselling into Therapeutic Practice

Shahar Gindi,Avital Pilpel 강원대학교 인문과학연구소 2015 Journal of Humanities Therapy Vol.6 No.2

Philosophical counselling is largely divided into those who accept and those who reject the medical model. From the latter stream, there are those who believe therapy is ineffective and that returning to open-ended, Socratic dialogues is the key towards greater insight and mental well-being. The first stream accepts psychotherapy is useful, but believes it does not pay enough attention to clients' metaphysical and moral views and their logical consistency. This stream tends to follow one of two traditions: logical investigations or existential philosophy. We suggest that this emphasis has underrepresented many useful philosophical approaches. We propose Contemporary Philosophical Counselling (CPC), a new approach designed as an aid to psychotherapists. CPC targets philosophical alongside psychological well-being with a well-defined target population. CPC focuses on building a systematic world-view in a collaborative discussion, informed by the plethora of philosophical streams in modern philosophy. Case examples are brought to illustrate this developing practice.

Silencing of ALA dehydratase affects ALA-photodynamic therapy efficacy in K562 erythroleukemic cells

Feuerstein, Tamar,Schauder, Avital,Malik, Zvi Korean Society of Photoscience 2009 Photochemical & photobiological sciences Vol.8 No.10

Synthesis of protoporphyrin IX (PpIX) by malignant cells is essential for the success of ALA-based photodynamic therapy (PDT). Two key enzymes that were described as affecting PpIX accumulation during ALA treatment are porphobilinogen deaminase (PBGD) and ferrochelatase. Here, we show that down regulation of ALA dehydratase (ALAD) expression and activity by specific shRNA induced a marked decrease in PpIX synthesis in K562 erythroleukemic cells. Photo-inactivation efficacy following ALA-PDT was directly correlated with ALAD-silencing and cellular levels of PpIX. MTT metabolism following ALA-PDT was shown to be 60% higher in ALAD-silenced cells in comparison to control cells, indicating that mitochondria were protected in the silenced cells. Morphological analysis by scanning electron microscopy (SEM) of cells treated by ALA-PDT showed no morphological changes in ALAD-silenced cells, in contrast to controls exhibiting cell deformations and lysis. Membrane integrity following ALA-PDT was kept intact and undamaged in ALAD-silenced cells as examined by Annexin V-FITC/PI staining and LDH-L leakage. We conclude that ALAD, although it is present in the cell at abundant levels, has a major and limiting role in regulating PpIX synthesis and ALA-PDT outcome.

Residents' Perceptions of the Socio-Cultural Impacts of Tourism in Kavala

Dimitrios Stylidis,Edith Szivas,Avital Biran 세계문화관광학회 2011 Conference Proceedings Vol.12 No.-

This paper investigates how residents of a tourist destination (Kavala) perceive the socio-cultural impacts of tourism on their community and examines whether factors tested in the past like residents' socio-demographic characteristics (age education and distance they live from the tourism zone) level of attachment to the community and their economic dependence on the tourism industry influence these perceptions. Although many studies in the past have examined residents' perceptions of the economic impacts of tourism the socio-cultural impacts have been less frequently studied especially in the context of an urban environment which is in the initial stages of tourism development. This paper filled this gap in the literature by collecting data from the city of Kavala in Greece. In the current study survey was selected as the most appropriate method for the primary data collection and a self-completed questionnaire was distributed to 500 adult residents of Kavala who were selected after a multi-stage cluster sampling technique was applied. The findings of the study revealed differences in residents' perceptions of tourism impacts due to factors like respondents' economic reliance on tourism and their level of attachment to Kavala. These results have important implications for the planning and development of tourism both in Kavala as well as in other destination with similar characteristics.

Residents’ Perceptions of the Socio-cultural Impacts of Tourism in Kavala

Dimitrios Stylidis,Edith Szivas,Avital Biran 한국문화관광학회 2011 문화관광연구 Vol.13 No.2

This paper investigates how residents of a tourist destination (Kavala) perceive the socio-cultural impacts of tourism on their community and examines whether factors tested in the past like residents’ socio-demographic characteristics (age, education and distance they live from the tourism zone), level of attachment to the community and their economic dependence on the tourism industry influence these perceptions. Although many studies in the past have examined residents’ perceptions of the economic impacts of the economic impacts of tourism, the socio-cultural impacts have been less frequently studied, especially in the context of an urban environment which is in the initial stages of tourism development. This paper filled this gap in the literature by collecting data from the city of Kavala in Greece. In the current study, survey was selected as the most appropriate method for the primary data collection and a self-completed questionnaire was distributed to 500 adult residents of Kavala, who were selected after a multi-stage cluster sampling technique was applied. The findings of the study revealed differences in residents’ perceptions of tourism impacts due to factors like respondents’ economic reliance on tourism and their level of attachment to Kavala. These results have important implications for the planning and development of tourism both in Kavala as well as in other destination with similar characteristics.

A computational model of ureteral peristalsis and an investigation into ureteral reflux

G. Hosseini,C. Ji,D. Xu,M. A. Rezaienia,E. Avital,A. Munjiza,J. J. R. Williams,J. S. A. Green 대한의용생체공학회 2018 Biomedical Engineering Letters (BMEL) Vol.8 No.1

The aim of this study is to create a computationalmodel of the human ureteral system that accuratelyreplicates the peristaltic movement of the ureter for avariety of physiological and pathological functions. Theobjectives of this research are met using our in-house fluidstructuraldynamics code (CgLes–Y code). A realisticperistaltic motion of the ureter is modelled using a novelpiecewise linear force model. The urodynamic responsesare investigated under two conditions of a healthy and adepressed contraction force. A ureteral pressure during thecontraction shows a very good agreement with correspondingclinical data. The results also show a dependencyof the wall shear stresses on the contraction velocity and itconfirms the presence of a high shear stress at the proximalpart of the ureter. Additionally, it is shown that an inefficientlumen contraction can increase the possibility of acontinuous reflux during the propagation of peristalsis.

2D materials: increscent quantum flatland with immense potential for applications

Ranjan Pranay,Gaur Snehraj,Yadav Himanshu,Urgunde Ajay B.,Singh Vikas,Patel Avit,Vishwakarma Kusum,Kalirawana Deepak,Gupta Ritu,Kumar Prashant 나노기술연구협의회 2022 Nano Convergence Vol.9 No.26

Quantum flatland i.e., the family of two dimensional (2D) quantum materials has become increscent and has already encompassed elemental atomic sheets (Xenes), 2D transition metal dichalcogenides (TMDCs), 2D metal nitrides/carbides/carbonitrides (MXenes), 2D metal oxides, 2D metal phosphides, 2D metal halides, 2D mixed oxides, etc. and still new members are being explored. Owing to the occurrence of various structural phases of each 2D material and each exhibiting a unique electronic structure; bestows distinct physical and chemical properties. In the early years, world record electronic mobility and fractional quantum Hall effect of graphene attracted attention. Thanks to excellent electronic mobility, and extreme sensitivity of their electronic structures towards the adjacent environment, 2D materials have been employed as various ultrafast precision sensors such as gas/fire/light/strain sensors and in trace-level molecular detectors and disease diagnosis. 2D materials, their doped versions, and their hetero layers and hybrids have been successfully employed in electronic/photonic/optoelectronic/spintronic and straintronic chips. In recent times, quantum behavior such as the existence of a superconducting phase in moiré hetero layers, the feasibility of hyperbolic photonic metamaterials, mechanical metamaterials with negative Poisson ratio, and potential usage in second/third harmonic generation and electromagnetic shields, etc. have raised the expectations further. High surface area, excellent young’s moduli, and anchoring/coupling capability bolster hopes for their usage as nanofillers in polymers, glass, and soft metals. Even though lab-scale demonstrations have been showcased, large-scale applications such as solar cells, LEDs, flat panel displays, hybrid energy storage, catalysis (including water splitting and CO2 reduction), etc. will catch up. While new members of the flatland family will be invented, new methods of large-scale synthesis of defect-free crystals will be explored and novel applications will emerge, it is expected. Achieving a high level of in-plane doping in 2D materials without adding defects is a challenge to work on. Development of understanding of inter-layer coupling and its effects on electron injection/excited state electron transfer at the 2D-2D interfaces will lead to future generation heterolayer devices and sensors.