Comparative study of CFD and 3D thermal-hydraulic system codes in predicting natural convection and thermal stratification phenomena in an experimental facility

Graževičius Audrius,Bousbia-Salah Anis 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.4

Natural circulation phenomena have been nowadays largely revisited aiming to investigate the performances of passive safety systems in carrying-out heat removal under accidental conditions. For this purpose, assessment studies using CFD (Computational Fluid Dynamics) and also 3D thermal-hydraulic system codes are considered at different levels of the design and safety demonstration issues. However, these tools have not being extensively validated for specific natural circulation flow regimes involving flow mixing, temperature stratification, flow recirculation and instabilities. In the present study, an experimental test case based on a small-scale pool test rig experiment performed by Korea Atomic Energy Research Institute, is considered for code-to-code and code-toexperimental data comparison. The test simulation is carried out using the FLUENT and the 3D thermal-hydraulic system CATHARE-2 codes. The objective is to evaluate and compare their prediction capabilities with respect to the test conditions of the experiment. It was observed that, notwithstanding their numerical and modelling differences, similar agreement results are obtained. Nevertheless, additional investigations efforts are still needed for a better representation of the considered phenomena.

Numerical investigation of two-component single-phase natural convection and thermal stratification phenomena in a rod bundle with axial heat flux profile

Graževičius Audrius,Šeporaitis Marijus,Valinčius Mindaugas,Kaliatka Algirdas 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.8

The most numerical investigations of the thermal-hydraulic phenomena following the loss of the residual heat removal capability during the mid-loop operation of the pressurized water reactor were performed according to simplifications and are not sufficiently accurate. To perform more accurate and more reliable predictions of thermal-hydraulic accidents in a nuclear power plant using computational fluid dynamics codes, a more detailed methodology is needed. Modelling results identified that thermal stratification and natural convection are observed. Temperatures of lower monitoring points remain low, while temperatures of upper monitoring points increase over time. The water in the heated region, in the upper unheated region and the pipe region was well mixed due to natural convection, meanwhile, there is no natural convection in the lower unheated region. Water temperature in the pipe region increased after a certain time delay due to circulation of flow induced by natural convection in the heated and upper unheated regions. The modelling results correspond to the experimental data. The developed computational fluid dynamics methodology could be applied for modelling of two-component single/ two-phase natural convection and thermal stratification phenomena during the mid-loop operation of the pressurized water reactor or other nuclear and non-nuclear installations at similar conditions

Antioxidant, Anti-inflammatory and Acetylcholinesterase Inhibitory Activities of Propolis from Different Regions of Morocco

Maria da Graça Miguel,Orsula Doughmi,Smail Aazza,Dulce Antunes,Badiaâ Lyoussi 한국식품과학회 2014 Food Science and Biotechnology Vol.23 No.1

Propolis is a bee product used since ancienttimes in folk medicine. Antioxidant activity is one of theproperties attributed to this natural product, which variesdepending on the botanical and geographic origin. Theantioxidant capacities of propolis from different regions ofMorocco were determined. Samples from the Khamissatand Immouzzer regions showed the highest antioxidantactivities (ABTS assay), reducing power, and peroxyl andhydroxyl radical scavenging capacities. The best capacitiesto inhibit 5-lipoxygenase were found in propolis samplesfrom Rabat. A strong correlation was found between theamounts of phenols, flavonoids, and antioxidant and antiinflammatoryactivities. These results support the hypothesisthat phenols contribute greatly to the pharma-cologicalproperties of propolis and suggest that propolis could beimportant in prevention of diseases in which free radicalsare implicated.

독일 토지거래법상 농지 거래시장 조정의 가능성과 한계

크리스티아네그라스 ( Christiane Graβ ),탁영남(번역) 영남대학교 법학연구소 2018 영남법학 Vol.0 No.47

독일 토지거래법은 부동산 거래를 규제한다. 그 목표는 농지를 농민에게 소유시키는 것을 목적으로 하고 경작을 목적으로 하지 않는 자본투자와 투기를 배제하려 한다. 그 방법은 인가와 그 거부이다. 인가는 부동산의 해로운 배분, 비경제적으로 축소될 때, 대응가치가 토지가치와 심한 불균형을 이룰 때 거부된다. 비농민이 농지를 매수하려고 하나 농민이 영농확장을 위해 그 농지를 긴급히 필요로할 때는 농민이 우선매수하게 된다. 행정청은 이를 심사하는 어려움이 매우 크다. 농민의 농력과 의지, 확장필요 여부 및 그 가치를 판단해야 한다. 이러한 문제는 신규취농자에 대하여 더욱 집중된다. 농민이 하루 아침에 되는 것은 아니기 때문에 신규취농자가 농지를 취득하려 할때는 조건부 인가가 부여되기도 한다. 몇 년 동안 다른 사람에게 용익 임대 하도록 하는 것이다. 실무상으로는 단순한 자본투자가가 장기간의 임대차를 전제로 농지를 취득하는 것은 현재로서는 불가능하다. 인가의무를 우회하는 방법으로 조합지분의 매수, 상속계약, 매매가의 고가화로 농민의 참여를 불가능하게 하는 것, 농지의 분할매매 등이 있다. 조합지분의 매수는 직접적으로는 농지를 매수하는 것이 아니라 농지를 소유하고 있는 조합의 지분을 매수하는 것이기 때문에 인가를 우회할 수 있다. 여기에는 매수인이 조합 지분의 전부를 매수하지 못하는 위험이 존재하기도 한다. 농지의 매매가인가 거부된 후 조합을 구성하여 농지를 매도하는 경우 인가가 거부된다. 상속계약은 농지 가격에 상당하는 금액을 임대료 등으로 지급하고 사인 증여받는 것이다. 여기에도 소유자가 일찍 사망하면 그 금액을 모두 받지 못할 위험성이 존재한다. 그리하여 저당권이 설정되기도 한다. 토지거래법이 인가를 통하여 거래시장을 조정하지만 우회라는 한계를 가진다. 재정적으로 강력한 단순한 자본 투자자가 농업구조 저해의 가장 큰 위험이다. 위와 같은 우회의 방법으로 투자가가 농지거래에 참여하는 것을 방지하려는 시도가 현재 진행 중이다. The German Land Transactions Act regulates farmland transactions, and its aim is for farmers to be able to own farmlands and to prevent a speculator or a capital investor who are not going to cultivate from owning farmlands. The methods are the approval and denial of the transaction requested. The approval may be denied when ⅰ) the transaction creates an unhealthy distribution, or ⅱ) divestiture would reduce or divide the land or a majority of real estate which is spatially or economically related and belongs to the transferor, or ⅲ) the equivalent value is grossly disproportionate to the value of the property When a nonfarmer is willing to buy the farmland and the farmland is necessary for the farmer who is urgent to procure it for large scale farming, the farmer has priority to buy the farmland under the same conditions which the nonfarmer would enter into. It is difficult for the agency to review whether the approval should be given or not, since it has to evaluate the ability and will of the farmer, the necessity for the large scale farming and the value of it. This problem is more concentrated regarding new farmers. Since farmers do not become farmers in a day, conditional approval may be granted when a new farmer wants to acquire farmland. Such approval could be contingent on allowing someone else to lease for a few years. In practice, it is currently impossible for a simple capital investor to acquire farmland on the premise of long-term lease. There are ways to circumvent the obligation of approval: purchase of union shares, the contract of inheritance, the prohibition of participation of farmers by the unaffordable sale price, and the partition sale of agricultural land. The purchase of a partnership stake is a way to circumvent the approval procedure because it is a purchase of a stake in the union that owns the farmland, rather than buying the farmland directly. In such a case, there is a risk that the buyer will not be able to buy all of the union shares. After the approval of the transaction of the farmland is denied, a new application by the union which is formed afterward for the approval may be denied. The contract of inheritance is to pay the amount equivalent to the price of the farm land through rent or the like and to receive donatio mortis causa. In this case, there is also the risk that if the owner dies early, he will not be able to receive all of the money. Thus, a mortgage could be established. The Land Transaction Act regulates the market through approval but has the limitation of circumvention. A simple financially strong capital investor is the greatest risk of hindering agricultural structure. Attempts are being made to prevent investors from participating in agricultural transactions through such a detour.

A SUPERFICIAL FRIENDSHIP THEORY PERSPECTIVE ON INTERNATIONAL MARKET ENTRY MODE INSTABILITY AND STABILITY

Lu-Yun (Vivian) Cheng,Graça Miranda Silva 글로벌지식마케팅경영학회 2016 Global Marketing Conference Vol.2016 No.7

International Joint Venture (IJV) is one of the most popular market entry mode in emerging markets. The instability and stability of IJV have also been receiving ongoing attention in the literature (e.g. Deitz et al. 2010; Kogut 1989; Rhoades & Lush 1997; Sim & Ali 2000). IJV instability and stability are often treated as opposite to one another in the literature, and assumed the factors that account for instability has an inverse impacts on stability. However, conceptually and empirically they are not exactly two contrasting phenomena. This study adopts the perspectives of Superficial Friendship theory (Yan 2010) to differentiate the determinants of IJV instability and stability and empirically compares their determinants. The results indicate that the factors that account for instability do not have inverse impacts on stability. The empirical results not only contribute to an understanding of the different drivers of IJV instability and stability but also have important implications for international business managers in both parents and IJVs with regard to keeping an IJV profitable and successful.

In vivo optical coherence tomographic imaging to monitor gingival recovery and the adhesive interface in aesthetic oral rehabilitation: A case report

Nathalia Del Rio Lyra Graça,Anna Rebeca de Barros Lins Silva Palmeira,Luana Osório Fernandes,Marlus da Silva Pedrosa,Renata Pedrosa Guimarães,Saulo Cabral dos Santos,Anderson Stevens Leonidas Gomes,Cl 대한영상치의학회 2019 Imaging Science in Dentistry Vol.49 No.2

The available methods for veneer evaluation are limited to clinical and radiographic examinations, which may not allow the appropriate identification of failure. In this report, we demonstrate the use of optical coherence tomography (OCT) as a noninvasive diagnostic and follow-up method to evaluate gingival recovery and the adhesive interface in aesthetic oral rehabilitation involving periodontal plastic surgery and ceramic laminate veneers. OCT was efficient for evaluating both soft and hard tissues, as well as the quality of the adhesive interface. In conclusion, OCT was found to be a promising approach for the professional evaluation of aesthetic oral rehabilitation, as it was capable of generating images that enabled the analysis of gingival recovery and the adhesive interface.

DETERMINANTS OF BRAIN DRAIN IN CHINESE FAMILY BUSINESS: A FUZZY-SET QUALITATIVE COMPARATIVE ANALYSIS

Huifen (Helen) Cai,Graça Miranda Silva 글로벌지식마케팅경영학회 2016 Global Marketing Conference Vol.2016 No.7

The paper investigates the Brain Drain in Chinese family business based on a sample of 319 family businesses in China. Using a fuzzy set qualitative comparative analysis (fsQCA) to uncover different combinations of conditions (pay and welfare, work environment, management style of the leaders, and career planning) that are sufficient to achieve high and low brain drain. The results show that pay and welfare is a necessary but not a sufficient condition by itself to achieve high brain drain. The findings show that three causal recipes are equifinal in achieving high brain drain. The first causal recipe combines high work environment with low level of career planning and with high pay and welfare. The second combines low work environment with high level of career planning and with high pay and welfare. Finally, the third combines high work environment with high level of management style of the leaders and with high pay and welfare. The study also found two causal configurations that are equifinal to achieve low brain drain. Moreover, these combinations are not a mirror of the combinations founded for high brain drain. This study offers several implications to both researchers and business practitioners: It is acquired that in order to prevent brain drain, the pay and welfare of employees should be raised while the management philosophy should pay attention to humans in the first place. Secondly, the leaders need to improve their own quality so as to strengthen the management of family businesses. Finally, a refined human resource system needs to be established. After brain drain, enterprises should perfect their contract constraining mechanism and, bring in suitable talents promptly so that the loss is minimised.

WHAT MOTIVATES EWOM IN HOTEL INDUSTRY? CAUSALEXPLANATIONS FROM FSQCA

Helena Martins Gonçalves,Graça Miranda Silva,Telma Gomes Martins 글로벌지식마케팅경영학회 2016 Global Marketing Conference Vol.2016 No.7

Web 2.0 has changed the way users create, share and use online information (O'Connor, 2008). The testimony of anonymous and exempt consumers that emits reviews and ratings through online reviews is a form of Electronic Word of Mouth (eWOM). Positive online reviews can contribute to a significant increase in hotel reservations (Ye, Law, & Gu, 2009). Online reviews are amidst the most important factors that influence hotel reservations (Dickinger & Mazanec, 2008) However, only a small percentage of travelers contribute actively with new reviews and evaluations (Bronner & Hoog, 2011). Thus, it is very important to know what motivates consumers to make online hotel reviews, to get more online comments and, consequently, more hotel reservations. Cantallops and Salvi (2014) say that there is little research on eWOM and hotels. The objective of this study is to identify the different causal combinations (configurations) of motivations (personal, social benefit, social concern, and consumer empowerment (Bronner & Hoog, 2011)), and socio-demographic characteristics (gender and age) that lead to hotel online reviews. The study uses the fuzzy-set Qualitative Comparative Analysis (fsQCA) because it allows to identify the necessary and sufficient configurations to achieve the outcome (Fiss, 2011). This is an innovative approach in this domain, to the best of our knowledge, because the study focuses on the causal recipes of motivations and not on the net effects of independent motivations as past research do. The study obtained a convenience sample of 192 valid responses, from an online survey.The measures show adequate reliability. The results show that the social concern is a necessary condition and the consumer empowerment is an “almost always necessary” condition. The analysis of sufficient conditions show that three different combinations (explain 43.6% of the cases) of conditions exist that lead to eWOM: 1) being a female older than 35 years old combined with high social concern and high consumer empowerment; 2) being a female older than 35 years old combined with high social concern and high personal motivations; and, 3) being a male combined with the presence of high social concern, high personal motivations, and high consumer empowerment which represents the most significant representation of consumers that make online reviews. Managers should consider these recipes in communication and website design strategies. For example, for men, it is important to have jointly a simple communication channel so that they can easily share positive or negative experiences to help others (social concern); a travel website where they get some fun (personal motivation); and, to believe that their opinions are taken into account by the hotels, namely to improve service (consumer empowerment). In this way,hotels and travel services providers promoting these aspects will tend to have more and better online reviews, which will have a positive influence on hotel reservations. Future studies should consider different motivations for online reviews and eWOM.

Growth and Nutritional Biomarkers in Brazilian Infants with Cow’s Milk Allergy at Diagnosis and 18-Month Follow-Up: A Prospective Cohort Study

Anne Jardim-Botelho,Tatiane Graça Martins,Jackeline Motta-Franco,Rosan Meyer,Sarah Cristina Fontes Vieira,Bruna Franca Protásio,Milena Letícia Santos Silva,Rebecca Silveira Pontes,Marcela Barros Barbo 대한소아소화기영양학회 2023 Pediatric gastroenterology, hepatology & nutrition Vol.26 No.6

Purpose: This study aimed to describe the growth, body protein status, and micronutrient biomarkers of Brazilian infants with cow’s milk allergy (CMPA) at baseline and at 18 months of follow-up in comparison with their healthy peers. Methods: Thirty infants with CMPA younger than six months of age were included in this longitudinal study, and their nutritional status was compared with that of 24 non-allergic age-matched children. Anthropometric measurements were used to assess growth, and blood and urine samples were analyzed for protein and micronutrient status. Mixed linear models adjusted for birth weight, socioeconomic status, infant feeding at baseline, weightfor- age, C-reactive protein, serum albumin, micronutrient dietary supplementation, and salt consumption were employed to evaluate the evolution of nutritional parameters throughout the follow-up period. Results: Overall, the mean age of the children at enrolment was 2.9 (standard deviation 1.7) months, and 29 children (53.7%) were male. Infants with CMPA showed a higher prevalence of functional iron depletion (transferrin saturation <20) (p=0.027), lower serum ferritin (p=0.009), and lower urinary iodine (p=0.034) levels than non-allergic children at baseline. Patients with CMPA showed a higher increment in weight-for-age and length-for-age over time than those in the control group (p<0.01). Mixed linear analyses showed a significantly lower increase in serum vitamin B12 (s-B12) (p=0.001) and urinary iodine (p<0.001) concentrations over time compared to the control group. Conclusion: Infants with CMPA on a cow’s milk elimination diet had a higher weight and length at 18 months of follow-up but showed signs of inadequate iron, iodine, and B-12 vitamin status.

Photovoltaic effect in the single-junction DBP/PTCBI organic system under low intensity of monochromatic light

Rafał Marczyński,Justyna Szostak,Ryszard Signerski,Grażyna Jarosz 한국물리학회 2019 Current Applied Physics Vol.19 No.11

Photoelectric properties of the planar ITO/MoO3/DBP/PTCBI/BCP/Ag system were characterized on the basis of short-circuit current, open-circuit voltage and absorption spectra, and current-voltage measurements in the dark and under monochromatic illumination of low intensity. Photovoltaic performance of the system was compared with the performance of ideal semiconductor and excitonic cells of chosen bandgaps. Such analysis shows, that the fabricated cell exhibits quite high value of the open-circuit voltage, in comparison to the SQ limits calculated for semiconductor devices of bandgaps close to the LUMOPTCBI-HOMODBP offset or crystalline silicon cells of the same absorptivity. This confirms that the DBP/PTCBI junction exhibits good properties for conversion of exciton energy to chemical energy of electron-hole pair. Moreover, open-circuit voltage and short-circuit current of the investigated cell practically do not change within the 520 nm–620 nm range, for which they reach the maximum values, making the junction of DBP/PTCBI attractive for use in indoor photovoltaics.