L_K-BIHARMONIC HYPERSURFACES IN SPACE FORMS WITH THREE DISTINCT PRINCIPAL CURVATURES

Aminian, Mehran Korean Mathematical Society 2020 대한수학회논문집 Vol.35 No.4

In this paper we consider L_K-conjecture introduced in [5, 6] for hypersurface Mⁿ in space form Rⁿ⁺¹(c) with three principal curvatures. When c = 0, -1, we show that every L₁-biharmonic hypersurface with three principal curvatures and H₁ is constant, has H₂ = 0 and at least one of the multiplicities of principal curvatures is one, where H₁ and H₂ are first and second mean curvature of M and we show that there is not L₂-biharmonic hypersurface with three disjoint principal curvatures and, H₁ and H₂ is constant. For c = 1, by considering having three principal curvatures, we classify L₁-biharmonic hypersurfaces with multiplicities greater than one, H₁ is constant and H₂ = 0, proper L₁-biharmonic hypersurfaces which H₁ is constant, and L₂-biharmonic hypersurfaces which H₁ and H₂ is constant.

Predicting the velocity distribution of Rushton turbine impeller in mixing of polymeric liquids using fuzzy neural network models

Ali Aminian,Mansour Jahangiri 한국화학공학회 2014 Korean Journal of Chemical Engineering Vol.31 No.5

Velocity profiles are helpful for the confident design of mixing tanks and chemical reactors in mixing processes. A fuzzy model and an artificial neural network have been presented for accurate prediction of velocity distributionof Rushton turbine impeller (RTI) for the mixing of polymeric liquids in the lower transition region: 35<Re'<1800. Local tangential and radial velocities were predicted along the discharge plane of the impeller. Experimental data wereused for training, validation, and testing the neuromorphic models. The presented models are very accurate and reliablein predicting the velocity profiles over wide ranges of polymer concentrations and rotational speed. Comparison of thesuggested fuzzy model and the empirical correlations shows that the proposed model outperforms the other alternativesboth in accuracy and generality. The results show that the proposed neuromorphic models can successfully be usedfor prediction of velocity distribution in agitated tanks for viscoelastic polymeric fluids.

Introduction of T-­harmonic Maps

Mehran Aminian 한국수학교육학회 2023 純粹 및 應用數學 Vol.30 No.2

In this paper, we introduce a second order linear differential operator $ \stackrel{T}{\Box}:C^\infty(M)\rightarrow C^\infty(M) $ as a natural generalization of Cheng-Yau operator, \cite{Yauoperator}, where $ T $ is a $ (1,1) $-tensor on Riemannian manifold $ (M,h) $, and then we show on compact Riemannian manifolds, divT=divT^t, and if divT = 0, and f be a smooth function on M, the condition $ \stackrel{T}{\Box}f=0 implies that f is constant. Hereafter, we introduce T-energy functionals and by deriving variations of these functionals, we define T-harmonic maps between Riemannian manifolds, which is a generalization of L_{k}-harmonic maps introduced in [3]. Also we have studied f$ T $-harmonic maps for conformal immersions and as application of it, we consider f$ L $ _{k}-harmonic hyper- surfaces in space forms, and after that we classify complete f$L$_{1}-harmonic surfaces, some f$L$_{k}-harmonic isoparametric hypersurfaces, f$L$_{k}-harmonic weakly convex hypersurfaces, and we show that there exists no compact f$L$_{k}-harmonic hypersurface either in the Euclidean space or in the hyperbolic space or in the Euclidean hemisphere. As well, some properties and examples of these definitions are given.

Insights into the significance of membrane structure and concentration polarization on the performance of gas separation membrane permeators: Mathematical modeling approach

Javad Aminian Dehkordi,Seyed Saeid Hosseini,Prodip K. Kundu 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.67 No.-

This study presents a mathematical modeling approach for developing models based on non-idealconditions related to the membrane structure including porous supporting layer and deformation underpressure. Comparison of thefindings with experimental data reveal the importance of considering theresistance in porous supporting layer though the effect of concentration polarization in the permeatestream could be neglected. Investigations on deformation offibers under pressure ascertain that at largerfiber inner radius to outer radius ratios, increasing driving force may lead to an initial increase inpermeability. After that, the effects of deformation dominates and thus permeability may be decreased.

{$L_k$}-biharmonic hypersurfaces in space forms with three distinct principal curvatures

Mehran Aminian 대한수학회 2020 대한수학회논문집 Vol.35 No.4

In this paper we consider $ L_k $-conjecture introduced in \cite{AminianKashani, AminKashani} for hypersurface $ M^n $ in space form $ R^{n+1}(c) $ with three principal curvatures. When $ c=0, -1 $, we show that every $ L_1 $-biharmonic hypersurface with three principal curvatures and $ H_1 $ is constant, has $ H_2=0 $ and at least one of the multiplicities of principal curvatures is one, where $ H_1 $ and $ H_2 $ are first and second mean curvature of $ M $ and we show that there is not $ L_2 $-biharmonic hypersurface with three disjoint principal curvatures and, $ H_1 $ and $ H_2 $ is constant. For $ c=1 $, by considering having three principal curvatures, we classify $L_1$-biharmonic hypersurfaces with multiplicities greater than one, $ H_1 $ is constant and $ H_2=0 $, proper $L_1$-biharmonic hypersurfaces which $ H_1 $ is constant, and $ L_2 $-biharmonic hypersurfaces which $ H_1 $ and $ H_2 $ is constant.

Trade in services

Nathalie Aminian,K.C. FUNG 인하대학교 산업경제연구소 2011 경상논집 Vol.25 No.2

This paper investigates the trend and characteristics of trade in services in two fertile regions where different forms of trade integration have taken place: East Asia and Latin America. To that end, the World Bank data are utilized to categorize services trade in order to put on view the national and regional positions on dynamic sectors, and to compare East Asia and Latin America in terms of revealed comparative advantages, the weight of service activities in the regional economic activity, the share of services employment. The paper deals also with the issue of internationalization of services through FDI. Overall, it shows the increasing importance of East Asia as a trading region while the share of North & Latin America is low and declining over time.

The Political Economy of Exchange Rates

Nathalie Aminian,K.C.Fung,Alicia Garcia-Herrero,Alan Siu 인하대학교 정석물류통상연구원 2009 인하대학교 정석물류통상연구원 학술대회 Vol.2009 No.10

This paper sets out a political economy model of exchange rates, focusing in the importance of external lobbying. Applying it to the recent history of the Chinese yuan, we show that pressure from the U.S. trade negotiators could lead to an appreciation of the Chinese yuan, as well as to a reduction in import prices and trade disequilibrium between the United States and China.

Foreign Direct Investment, Intra-Regional Trade and Production Sharing in East Asia

Nathalie Aminian,K.C. Fung,Hitomi Iizaka 인하대학교 정석물류통상연구원 2007 인하대학교 정석물류통상연구원 학술대회 Vol.2007 No.10

Effect of Alternaria solani Exudates on Resistant and Susceptible Potato Cultivars from Two Different pathogen isolates

Shahbazi, Hadis,Aminian, Heshmatollah,Sahebani, Navazollah,Halterman, Dennis The Korean Society of Plant Pathology 2011 Plant Pathology Journal Vol.27 No.1

Early blight of potato, caused by Alternaria solani, is a ubiquitous disease in many countries around the world. Our previous screening of several Iranian potato cultivars found that significant variation in resistance phenotypes exists between two cultivars: resistant 'Diamond' and susceptible 'Granula'. Our previous analysis of five different pathogen isolates also identified varying degrees of aggressiveness regardless of the host cultivar. Here, a bioassay was used to study the role of liquid culture exudates produced in vitro on pathogenicity and elicitation of disease symptomology in seedlings as well as detached leaves. Responses of host genotypes to the exudates of the two A. solani isolates were significantly different. Detached leaves of the resistant cultivar 'Diamond' elicited fewer symptoms to each isolate when compared to the susceptible cultivar 'Granula'. Interestingly, the phytotoxicity effect of the culture filtrate from the more aggressive isolate A was higher than from isolate N suggesting an increased concentration or strength of the toxins produced. Our results are significant because they indicate a correlation between symptoms elicited by A. solani phytotoxins and their aggressiveness on the host.

Comparison of accuracy between panoramic radiography, cone-beam computed tomography, and ultrasonography in detection of foreign bodies in the maxillofacial region: an in vitro study

Abdinian, Mehrdad,Aminian, Maedeh,Seyyedkhamesi, Samad The Korean Association of Oral and Maxillofacial S 2018 대한구강악안면외과학회지 Vol.44 No.1

Objectives: Foreign bodies (FBs) account for 3.8% of all pathologies of the head and neck region, and approximately one third of them are missed on initial examination. Thus, FBs represent diagnostic challenges to maxillofacial surgeons, rendering it necessary to employ an appropriate imaging modality in suspected cases. Materials and Methods: In this cross-sectional study, five different materials, including wood, metal, glass, tooth and stone, were prepared in three sizes (0.5, 1, and 2 mm) and placed in three locations (soft tissue, air-filled space and bone surface) within a sheep's head (one day after death) and scanned by panoramic radiography, cone-beam computed tomography (CBCT), and ultrasonography (US) devices. The images were reviewed, and accuracy of the detection modalities was recorded. The data were analyzed statistically using the Kruskal-Wallis, Mann-Whitney U-test, Friedman, Wilcoxon signed-rank and kappa tests (P<0.05). Results: CBCT was more accurate in detection of FBs than panoramic radiography and US (P<0.001). Metal was the most visible FB in all of modalities. US was the most accurate technique for detecting wooden materials, and CBCT was the best modality for detecting all other materials, regardless of size or location (P<0.05). The detection accuracy of US was greater in soft tissue, while both CBCT and panoramic radiography had minimal accuracy in detection of FBs in soft tissue. Conclusion: CBCT was the most accurate detection modality for all the sizes, locations and compositions of FBs, except for the wooden materials. Therefore, we recommend CBCT as the gold standard of imaging for detecting FBs in the maxillofacial region.