109 research outputs found
On stability problem for the stationary Boussinesq system in Morrey-type spaces
In this paper we establish the asymptotic stability of steady solutions for
the Boussinesq systems in the framework of Cartesian product of critical
weak-Morrey spaces on , where . In our strategy,
we first establish the continuity for the long time of the bilinear terms
associated with the mild solutions of the Boussinesq systems, i.e., the
bilinear estimates by using only the norm of the present spaces. As a direct
consequence, we obtain the existence of global small mild solutions and
asymptotic stability of steady solutions of the Boussinesq systems in the class
of continuous functions from to the Cartesian product of critical
weak-Morrey spaces. Our techniques consist interpolation of operators, duality,
heat semigroup estimates , Holder and Young inequalities in block spaces (based
on Lorentz spaces) that are preduals of Morrey-Lorentz spaces. Our results are
generalized the previous ones of the steady Boussinesq systems in weak-
spaces obtained by Hishida [T. Hishida, {\it On a class of Stable Steady flow
to the Exterior Convection Problem}, Journal of Differential Equations, Vol.
141, Iss. 1 (1997), pages 54-85] and Ferreira et al. [L.C.F. Ferreira and E.J.
Villamizar-Roa, {\it On the stability problem for the Boussinesq equations in
weak- spaces}, Commun. Pure Appl. Anal. (2010), Vol. 9, No. 3, pages
667-684] and of the Navier-Stokes equations in Morrey spaces obtained by Kozono
et al. [H. Kozono and M. Yamazaki, {\it The stability of small stationary
solutions in Morrey Spaces of the Navier-Stokes equation}, Indiana University
Mathematics Journal, Vol. 44, No. 4 (1995), pages 1307-1336].Comment: 17 page
Straightforward Procedure for Laboratory Production of DNA Ladder
DNA ladder is commonly used to determine the size of DNA fragments by electrophoresis in routine molecular biology laboratories. In this study, we report a new procedure to prepare a DNA ladder that consists of 10 fragments from 100 to 1000 bp. This protocol is a combination of routinely employed methods: cloning, PCR, and partial digestion with restriction enzymes. DNA fragments of 100 bp with unique restriction site at both ends were self-ligated to create a tandem repeat. Once being cloned, the tandem repeat was rapidly amplified by PCR and partially digested by restriction enzymes to produce a ladder containing multimers of the repeated DNA fragments. Our procedure for production of DNA ladder could be simple, time saving, and inexpensive in comparison with current ones widely used in most laboratories
Experiment program of shake table test on a precast frame made of recycled aggregate concrete
A precast frame model made of Recycled Aggregate Concrete (RAC) been constructed with precast beams, columns and Cast-In-Place (CIP) joints. Then a shaking table test was carried out with three types of earthquake ground motions, namely Wenchuan, El Centro and artificial Shanghai waves. Based on the shaking test, the test program is presented and analyzed. The paper focuses on the shaking test program, including materials, similitude law and scaled model, instruments, seismic waves and loading program. Consequently, a comprehensive understanding on the process of shake table test is revealed thanks to the results of an investigation on a precast frame structure made of recycled aggregate concrete
Monetary policy and bank liquidity creation: does bank size matter?
This paper investigates the effect of monetary policy on liquidity creation of commercial banks and if the effect is conditional on bank size. The paper uses a dataset covering 23 Vietnamese commercial banks during the period 2007–2017 collected from various sources including State Bank of Vietnam, International Monetary Fund, SNL Financial database (provided by SNL Company), Vietnam General Statistic Office and banks’ annual reports. Different econometric techniques are employed to analyse the data. Obtained results indicate that a contractionary monetary policy could lead to a decrease in bank liquidity creation. This result is less pronounced with larger banks. In particular, among three monetary policy instruments employed in Vietnam, an increase in the base rate is significantly associated with a contraction in bank liquidity creation; open market operations may have a marginal impact while required reserve ratio is ineffective because of its unchanged value throughout the period of the study. This paper is among the first, providing an insight into each monetary policy instrument's role in influencing bank liquidity creation in the context of an emerging economy
3D unsteady turbulent flow analysis in a Francis turbine runner at nominal and off-design operating conditions
This paper presents the use of a commercial Navier-Stokes turbulent flow code (FLUENT) as a mean to evaluate the behavior of a Francis turbine runner for the design and off-design conditions. The flow in the runner is analyzed numerically at different operating points. The numerical results permit to observe physical phenomena in the runner that are important in the process of hydraulic turbo machinery design. Values of different velocity components in the flow, blade pressure distribution ... given by the model are compared with experimental data at nominal and off-design flow conditions. Computer resource involves in the flow analysis should be compatible with the need of design process of a runner. Therefore 12 hours of CPU time can be considered as acceptable for calculating at each operating point on a computer workstation of medium size power
TURBIDITY REMOVAL BY MUCILAGE FROM BASELLA ALBA
Coagulation and flocculation are preliminary used in water treatment processes for turbidity removal, using popularily synthetic chemicals with health and environmental concerns. The use of natural flocculants has known to be a promising alteratives for chemical ones due to their environmental friendly behavior. This research investigated turbidity removal efficiency of mucilage extracted from Basella alba - an indigenous species in Vietnam - in the role of a flocculant. The removal efficiency of mucilage was investigated in combination with PAC or Alum on To Lich river water by mean of Jar tests. PAC or Alum alone can remove maximum 97% and 90% turbidity of To Lich river water at its original pH for the sedimentation time of 30 minutes. The combination of mucilage and PAC or Alum increased the efficiencies of turbidity removal and reduced the amount of chemicals needed. The corresponding increases were maximum 7% and 18%, respectively; while the reduction of PAC/Alum used was 75-80%
Infection status and molecular identification of digenean cercariae in snails in Kim Son district, Ninh Binh Province and Ba Vi district, Ha Noi
In this study, the molecular method was used to identify digenean cercariae from freshwater snails in Kim Son District (Ninh Binh Province) and Ba Vi District Ha Noi. A total of 9 snail species were collected and examined for cercarial infection. Three snail species (Radix swinhoei, Angulyagra polyzonata and Pomacea canaliculata) were not infected, while the other 6 species (Austropeplea viridis, Gyraulus convexiusculus, Parafossarulus striatulus, Bithynia fuchsiana, Melanoides tuberculata and Tarebia granifera) were infected with digenean cercariae at low infection rates, ranging from 2.3% to 6.3%. Seven cercarial groups were identified: Echinostome, Monostome, Parapleurophocercaria, Xiphidiocercaria, Fucocercaria, Gymnocephalous and Megalurous. Snails M. tuberculata and P. striatulus were infected with 4 cercarial groups, A. viridis and G. convexiusculus snails were infected with 2 groups, 2 snail species B. fuchsiana and T. granifera were infected with one group of cercaria. The results of ITS2 sequences analyses of the cercarial groups identified the larvae of 9 trematode species, namely Echinostoma revolutum, Echinochasmus japonicus, Notocotylus intestinalis, Philophthalmus gralli, Haplorchis pumilio, Procerovum cheni, Fasciola gigantica, Australapatemon burti and Cyathocotyle prussica. Among them the last three species, P. cheni, A. burti and C. prussica, were found for the first time in Vietnam. In addition, the ITS-2 sequence of Gymnocephalous cercariae which was previously identified as Sphaeridiotrema monorchis, from P. striatulus snail was 97% similar to that of Sphaeridiotrema pseudoglobulus. Likewise, ITS-2 sequence of Echinostome cercaria from B. fuchsiana snail was 93% similar to that of E. japonicus and that of Xiphidiocercaria cercaria from M. tuberculata snail was 93% similar to Lecithodendrium spathulatum.
Comparison of velocity distribution in turbulent diffusion jet given by the integral model and code CFD FLUENT 6.0
Integral model is simple in utilization, low in CPU time calculation, suitable for a lot of practical applications of turbulent diffusion jet. However the assessment of accuracy of the model should be carried out by experimental data and by results of available multidirectional codes. The present paper shows the comparison of velocity profiles given by the integral model and the CFD FLUENT 6.0 Code. The difference in results given by the two models is lower than 10% when Reynolds number at the exit nozzle below 5000
A comparison for donor-acceptor interactions between E(PH3)2 and NHEMe ligands (E = C to Pb) of W(CO)5 complexes using energy decomposition analysis method with natural orbitals for chemical valence theory
Quantum chemical calculations at the BP86/TZ2P+ level of theory are performed for a comparison of density functional theory (DFT) between tetrylones [(CO)5W-{E(PH3)2}] (W5-EP2) and tetrylenes [(CO)5W-{NHEMe}] (W5-NHEMe) when E = C to Pb. The EDA-NOCV results suggest that the W-E bond dissociation energies (BDEs) in tetrylone complexes increase from the lighter to the heavier homologues. The W-E bond dissociation energies (BDEs) trend in W5-EP2 comes from the increase in (CO)5W←E(PH3)2 donation and strong electrostatic attraction, and that the ligands E(PH3)2 (EP2) are strong s-donors and very weak π-donors. The W-E BDEs trend in tetrylene complexes W5-NHEMe is opposite to that of the W5-EP2 complexes which decrease from the lighter to the heavier homologues. The NHEMe ligands are strong s-donors and weak π-acceptors. NOCV pairs were used in a description of the chemical bond between the W(CO)5 fragment and the ligands in the transition-metal complexes and the results indicated that the NOCV pairs lead to very valuable description of the bonding situation of the fragment-ligand bond in complexes. Keywords. Density functional theory; Bond dissociation energies (BDEs); Energy decomposition analysis (EDA); Natural Orbitals for Chemical Valence (NOCV)
THE EFFECT OF SUPPORT FROM ORGANIZATIONS AND TRANSFORMATIONAL LEADERSHIP ON AFFECTIVE COMMITMENT OF EMPLOYEES OF INDUSTRIAL ENTERPRISES OF VIETNAM
He result of a survey of 547 workers at Vietnamese industrial enterprises shows that the organizational support and the transformation leadership have a positive and statistically significant correlation with emotional commitment. The results of the regression analysis confirm that the organizational support has more influence than the transformational leadership on emotional commitment. In addition, the social package and charisma have the strongest effect on emotional commitment. This study also showed that transformational leadership has a moderating effect on the interaction between organizationalal support and emotional commitment. The study suggests some recommendations to improve the workers’s emotional commitment to the organization
- …