Geometrically nonlinear and dynamic analysis of Euler-Bernoulli beams using isogeometric approach

This paper presents a numerical procedure for geometrically nonlinear and dynamic analysis of Euler-Bernoulli beams based on the framework of isogeometric approach. The method utilizes B-spline as the basis functions for both geometric representation and analysis. Only one deflection variable (without rotational degrees of freedom) is used for each control point. It allows us to use few degrees of freedom while retaining high accuracy of solution. Two numerical examples are provided to illustrate the effectiveness of present method

Thermal buckling analysis of laminated composite plates using edge-based smoothed discrete shear gap method

In this paper, we analyze a thermal buckling behavior of laminated composite plates based on first-order shear deformation theory (FSDT) using edge-based smoothed discrete shear gap method (ES–DSG). In the ES-DSG, only the linear approximation is necessary and the discrete shear gap method (DSG) for triangular plate elements is used to avoid the shear locking and spurious zero energy modes. In addition, the stiffness matrices are computed based on smoothing domains created by connecting two end-nodes of the edge to centroids of adjacent triangular elements. The temperature in the plates is assumed to be uniform distribution and rise. Several numerical examples are given to verify the reliability of the obtained results compared to other published solutions

Static and dynanic analysis of composite plate using the C0-type higher-order shear deformation theory

This paper presents a novel numerical procedure based on edge-based smoothed finite element method (ES–FEM) in combination with the C0-type higher-order shear deformation theory (HSDT) for static and dynamic analysis of laminated composite plate. In the present ES–FEM, only the linear approximation is necessary and the discrete shear gap method (DSG) for triangular plate elements is used to avoid the shear locking and spurious zero energy modes. In addition, the stiffness matrices are computed based on smoothing domains associated with the edges of the triangular elements through a strain smoothing technique. Using the C0-type HSDT, the shear correction factors in the original ES-DSG3 can be removed and replaced by two additional degrees of freedom at each node. Several numerical examples are given to show the performance of the proposed method and results obtained are compared to other available ones

OPTIMIZING THE PRODUCTION OF A FUNCTIONAL TYPE A RECOMBINANT ENDOCHITINASE FROM Trichoderma asperellum IN Escherichia coli

Chitinases from the genus Trichoderma fungi are mainly responsible for their anti-fungal activities, which allow them to become the most widely used fungal biocontrol. Therefore, several Trichoderma chitinases have been cloned and expressed to facilitate their production and applications. A previous study of the same authors has characterized an endochitinase from a relatively novel Trichoderma spp., Trichoderma asperellum. To produce this enzyme more economically and efficiently, we reported the synthesis and expression of its synthetic encoding gene in the Escherichia coli M15 strain and established the optimal conditions for preparative scale production of the enzyme in its functional form. By lowering the induction temperatures, we observed substantial improvement in the expression levels of the active enzyme.  At 30 oC and 0.5 mM IPTG induction, 1 L of cells yielded approximately 80 - 100 mg of soluble protein, accounting for about 9-11 % of total soluble protein. This figure may be an underestimation of the actual yield, as deduced from the SDS-PAGE data. The recombinant enzyme can be retrieved by simple repeated freezing and thawing cycles and purified to near homogeneity using Ni-NTA chromatography. The purified enzyme showed in vitro colloidal chitin hydrolysis activity. These results could be scaled up to produce soluble 42 kDa chitinase in E. coli. The study demonstrated an economical method to produce chitinases for various agricultural and environmental applications

Optimizing Boiler Efficiency by Data Mining Teciques: A Case Study

In a fertilizer plant, the steam boiler is the most important component. In order to keep the plant operating in the effective mode, the boiler efficiency must be observed continuously by several operators. When the trend of the boiler efficiency is going down, they may adjust the controlling parameters of the boiler to increase its efficiency. Since manual operation usually leads to unex-pectedly mistakes and hurts the efficiency of the system, we build an information system that plays the role of the operators in observing the boiler and adjusting the controlling parameters to stabilize the boiler efficiency. In this paper, we first introduce the architecture of the information system. We then present how to apply K-means and Fuzzy C-means algorithms to derive a knowledge base from the historical operational data of the boiler. Next, recurrent fuzzy neural network is employed to build a boiler simulator for evaluating which tuple of input values is the best optimal and then automatically adjusting controlling inputs of the boiler by the optimal val-ues. In order to prove the effectiveness of our system, we deployed it at Phu My Fertilizer Plant equipped with MARCHI boiler having capacity of 76-84 ton/h. We found that our system have improved the boiler efficiency about 0.28-1.12% in average and brought benefit about 57.000 USD/year to the Phu My Fertilizer Plant

How does the knowledge accumulation process affect Vietnamese entrepreneurs’ success likelihood?

The nationwide economic reform in 1986 transformed Vietnam from a centrally planned economy to a socialist-oriented market economy. Entrepreneurs and entrepreneurial spirits within the populace are suggested to fuel the structural changes. Despite the importance of entrepreneurship in Vietnam’s economy, studies in Vietnam mainly pay attention to the practical aspects of entrepreneurial activities and neglect the cognitive and theoretical aspects of entrepreneurship. Thus, the current study employs the information-processing perspective of the Mindsponge Theory to explore how entrepreneurs’ knowledge accumulation can affect their perceived likelihood of business success. Bayesian analysis indicates that business-related experience positively affects entrepreneurs’ business success likelihood. Greater willingness/readiness to transform thinking, acting, and beliefs can improve the business success of entrepreneurs who study others’ failures carefully. However, for entrepreneurs who perceive learning from others’ failures as unnecessary, higher willingness/readiness to transform diminishes their chance of success. Based on these findings, we recommend Vietnamese entrepreneurs accumulate knowledge through experience, learning, and an open mind for better decision-making and innovation creation capabilities. However, the learning process should be selective

TẠO DÒNG CÁC GEN MÃ HÓA CHITINASE 42 kDa CỦA Trichoderma asperellum VÀO VECTOR BIỂU HIỆN THỰC VẬT pMYV719 ĐỂ PHỤC VỤ CHUYỂN GEN

In this study, chitinase genes containing a signal peptide sequence, such as Chi42, syncodChi42-1 and syncodChi42-2, were cloned in the plant expression vector pMYV719 and successfully transferred into Agrobacterium tumefaciens LBA 4404. Among them, Chi42 is a wild-type gene of Trichoderma asperellum SH16. Both genes syncodChi42-1 and syncodChi42-2 are derived from Chi42, which was optimized for codon usage for plant expression. Agrobacterium bacteria-harbouring pMYV719/chitinase vector was used for genetic transformation into peanuts (Arachis hypogaea L.) to enhance resistance to phytopathogenic fungi in further studies.Trong nghiên cứu này, các gen chitinase mang trình tự peptide tín hiệu như Chi42, syncodChi42-1 và syncodChi42-2 đã được tạo dòng trong vector biểu hiện thực vật pMYV719 và biến nạp thành công vào vi khuẩn Agrobacterium tumefaciens LBA 4404. Trong đó, gen Chi42 là kiểu gen hoang dại từ chủng nấm Trichoderma asperellum SH16. Hai gen syncodChi42-1 và syncodChi42-2 có nguồn gốc từ gen Chi42 đã được tối ưu hóa bộ ba sử dụng để biểu hiện thực vật. Vi khuẩn A. tumefaciens mang các gen chitinase được sử dụng để chuyển gen vào cây lạc (Arachis hypogaea L.) trong các nghiên cứu tiếp theo để cải thiện khả năng kháng nấm bệnh của chúng

Terpenoids from Dacrycarpus imbricatus.

The phytochemical investigation of the hexane extract from the twigs and leaves of Dacrycarpus imbricatus (Blume) de Laub led to the isolation of a rare sesquiterpene, spathulenol (1) along with three diterpenes named pimaric acid (2), trans-communic acid (3) and cis-communic acid (4). Their structures were determined by combination of spectral analysis and comparison with reported data. This is the first report on isolation of compound 1 from the Podocarpaceae family. Keywords. Dacrycarpus imbricatus, spathulenol, pimaric acid, communic acid

Concomitant Bacteremia in Adults With Severe Falciparum Malaria.

BackgroundApproximately 6% of children hospitalized with severe falciparum malaria in Africa are also bacteremic. It is therefore recommended that all children with severe malaria should receive broad-spectrum antibiotics in addition to parenteral artesunate. Empirical antibiotics are not recommended currently for adults with severe malaria.MethodsBlood cultures were performed on sequential prospectively studied adult patients with strictly defined severe falciparum malaria admitted to a single referral center in Vietnam between 1991 and 2003.ResultsIn 845 Vietnamese adults with severe falciparum malaria admission blood cultures were positive in 9 (1.07%: 95% confidence interval [CI], .37-1.76%); Staphylococcus aureus in 2, Streptococcus pyogenes in 1, Salmonella Typhi in 3, Non-typhoid Salmonella in 1, Klebsiella pneumoniae in 1, and Haemophilus influenzae type b in 1. Bacteremic patients presented usually with a combination of jaundice, acute renal failure, and high malaria parasitemia. Four bacteremic patients died compared with 108 (12.9%) of 836 nonbacteremic severe malaria patients (risk ratio, 3.44; 95% CI, 1.62-7.29). In patients with >20% parasitemia the prevalence of concomitant bacteremia was 5.2% (4/76; 95% CI, .2-10.3%) compared with 0.65% (5/769; 0.08-1.2%) in patients with ConclusionsIn contrast to children, the prevalence of concomitant bacteremia in adults with severe malaria is low. Administration of empirical antibiotics, in addition to artesunate, is warranted in the small subgroup of patients with very high parasitemias, emphasizing the importance of quantitative blood smear microscopy assessment, but it is not indicated in most adults with severe falciparum malaria

A Retrospective Analysis of the Haemodynamic and Metabolic Effects of Fluid Resuscitation in Vietnamese Adults with Severe Falciparum Malaria

BACKGROUND: Optimising the fluid resuscitation of patients with severe malaria is a simple and potentially cost-effective intervention. Current WHO guidelines recommend central venous pressure (CVP) guided, crystalloid based, resuscitation in adults. METHODS: Prospectively collected haemodynamic data from intervention trials in Vietnamese adults with severe malaria were analysed retrospectively to assess the responses to fluid resuscitation. RESULTS: 43 patients were studied of whom 24 received a fluid load. The fluid load resulted in an increase in cardiac index (mean increase: 0.75 L/min/m(2) (95% Confidence interval (CI): 0.41 to 1.1)), but no significant change in acid-base status post resuscitation (mean increase base deficit 0.6 mmol/L (95% CI: -0.1 to 1.3). The CVP and PAoP (pulmonary artery occlusion pressure) were highly inter-correlated (r(s) = 0.7, p<0.0001), but neither were correlated with acid-base status (arterial pH, serum bicarbonate, base deficit) or respiratory status (PaO(2)/FiO(2) ratio). There was no correlation between the oxygen delivery (DO(2)) and base deficit at the 63 time-points where they were assessed simultaneously (r(s) = -0.09, p = 0.46). CONCLUSIONS: In adults with severe falciparum malaria there was no observed improvement in patient outcomes or acid-base status with fluid loading. Neither CVP nor PAoP correlated with markers of end-organ perfusion or respiratory status, suggesting these measures are poor predictors of their fluid resuscitation needs