Efficiency of GCSC-BtA, as a new type of biocide, on different agricultural arthropod pests and its side-effect on some predators

A new type of biocide GCSC-BtA, named from "Germany-China Scientific Cooperation-Bacillus thuringiensis-Abamectin", was successfully developed by conjugating delta-endotoxin of Bacillus thuringiensis (B.t.) with Abamectin from Streptomyces avermitilis through conjugator EDC for control of different agricultural arthropod pests. The laboratory results of efficiency of biocide GCSC-BtA to four different arthropod pests and its side-effect on two species of predators are presented in this paper. The results showed significant differences in the mortalities of Tetranychus cinnabarinus (BOISD.) (Acari, Tetranychidae), Frankliniella occidentalis PERGANDE (Thys., Thripidae), Aphis fabae SCOPOLI (Hom., Aphididae) and Cameraria ohridella DESCHKA ET DIMI´C (Lep., Gracillariidae) caused by treatment of 0.6250 mg/ml of formulated product of GCSC-BtA, B.t., Abamectin and Cypermethrin. GCSC-BtA treatment caused higher mortalities of 86.37%, 94.82%, 94.15% and 93.23% in T. cinnabarinus, F. occidentalis, A. fabae and C. ohridella, respectively. Mortalities caused by Abamectin treatment were 73.92%, 63.3%, 86.52% and 73.48%, and by Cypermethrin treatment were 44.29%, 57.28%, 97.68% and 51.26%, respectively. B.t. could only kill C. ohridella with 87.62% mortality. Pesticidal treatment gave variations in mortalities of Orius strigicollis POPPIUS (Het., Anthocoridae) and Stethorus cantonensis PANG (Col., Coccinellidae) predators at p < 0.01, where 0.6250 mg/ml GCSC-BtA caused 21.76% and 32.42% mortalities, while the same rate of products of Abamectin with 73.26% and 87.67% as well as Cypermethrin with 86.43% and 93.83% mortalities, respectively. It is concluded that the biocide GCSC-BtA has increased efficacies as well as host ranges of B.t. and Abamectin, but displayed safer to some predators

How can Portugal attract more China´S young generation tourists?

Portugal as a tourism destination has great potential to be further developed, however it is still not well known by the Chinese outbound tourists, especially the young generation who would stay longer and spend more in Portugal. This paper describe the current situation of Portugal tourism in Chinese outbound market, after analyzing explained why Portugal should aim at the young generation, and finally gave some recommendations of how to attract them, mainly through social media platforms

Processing, microstructure and mechanical properties of beta-type titanium porous structures made by additive manufacturing

Tissue engineering through the application of a low modulus, high strength format as a potential approach for increasing the durability of bone implants has been attracting significant attention. Titanium alloys are widely used for biomedical applications because of their low modulus, high biocompatibility, specific strength and corrosion resistance. These reasons affirm why titanium alloy is selected as the specific material to research. The development of low modulus biomaterials is considered to be an effective method to remove the mismatch between biomaterial implants and surrounding bone tissue, thereby reducing the risk of bone resorption. So far, Ti–24Nb–4Zr–8Sn alloy (abbreviated hereafter as Ti2448) is considered to be a biomedical titanium alloy with low modulus, and was invented for biomaterial application. However, the modulus of Ti2448 (42-50 GPa) is still higher than that of bone (1-30 GPa). A scaffold is an ideal structure for bone implants; such a structure can further reduce the modulus of an implant. This structure also has the desired effect of promoting bone in-growth. Additive manufacturing could prepare porous titanium parts with mechanical properties close to those of bone tissue. However, the properties of scaffolds are affected by manufacturing strategies and parameters such as the scanning speed, the input power, the layer thickness, the scanning strategy, the temperature of the platform and the hatch distance. Each of these parameters can affect a scaffold’s properties and performance in terms of density, hardness, super-elastic property, compressive and fatigue properties. For the Ti2448 alloy, all of these manufacturing parameters are still not clear enough to develop the perfect porous structure. This study will examine the performance of biomaterial Ti2448 scaffolds by tuning the main parameters of additive manufacturing (AM) systems through an analysis of the microstructure and the mechanical properties of the produced components

Finite element analysis of stress distribution within metal-on-metal joint replacements

Demand for joint replacements is rising in Australia, driven by a sharp increase in the number of joint problems associated with population aging and obesity. In artificial joints, delamination or failure within the coatings occurs when the stress reaches a critical level, resulting in large wear debris particles appearing on the contact surface between the head and the cup. The process has been described as due to a stress-corrosion-cracking mechanism. Under the same loading, stress increases when the contact area decreases, which happens in the vicinity of wear debris. As such, once wear debris is generated, a catastrophic process could be initiated, resulting in more stress-corrosion-cracking. As such, acquiring a strong coating that will not fail is highly desirable for the applications of hip joint replacement. Failure in a coating layer is normally initiated by excessive local tensile or shear stress; therefore, it is important to clarify the stress distribution within the coating layer under different loading conditions, which is necessary for improving the load-carrying capability of the coating. Unlike previous studies, the multilayer diamond-like carbon (DLC) coatings having high elastic modulus and hardness were analysed in this work. Under normal contact conditions, plastic deformation occurs in contacting materials when the contact pressure is greater than the hardness of the materials. Therefore, high hardness coatings can resist plastic deformation to avoid failure of the coating; in addition, multilayer coatings can decrease stress concentration to avoid cracking. The purpose of this study is to determine whether DLC multilayer coatings can improve the property of the coating against potential cracking in the coating. It has been shown that structurally graded coatings had effect on reducing the contact-induced stress among all the factors considered. It is anticipated that the multilayer design parameters will be important to understand the stress distribution within metal-on-metal (MOM) hip replacements

Dynamic Current Control to Compensate for Magnetic Mutual Coupling in Electrically Excited Synchronous Machines

Electrically excited synchronous machines have become an attractive solution to electric vehicles. Equipped with a field winding in the rotor, the excitation of the machine is controllable. However, due to the magnetic mutual coupling between the stator and rotor windings, a voltage will be induced in the field winding in case of a current rise in the stator winding and vice versa. In this study, a dynamic current control algorithm with compensation for magnetic mutual coupling is proposed. A first-order response of current rise is expected. To achieve this, the controller consists of three parts. The first part is the feed forward of cross-coupling terms due to Park transform. The second part takes care of the resistances and selfinductances. The third part takes care of the mutual inductances. Finally, the outputs from the three parts are summed up to be the total output from the controller

Design of Electrically Excited Synchronous Machines to Achieve Unity Power Factor in Field Weakening for Long-Haul Electric Trucks

Electrically excited synchronous machines are a promising candidate for long-haul electric trucks due to excellent capability in field weakening. This study aims at concluding a structural design process of the machine for long-haul electric trucks. A criterion of machine design to achieve unity power factor in field-weakening is derived. With this criterion, a minimum level of field current is decided in the design process. Parametric sweeps are applied to decide the optimum slot geometries for stator and rotor. The optimization of slot geometries is multi-objective. In this study, it is to maximize the peak torque while minimize iron-core losses simultaneously. Pareto frontier is used to identify the optimum solutions. The performance of the finalized design is then evaluated. The high efficiency area is located at high-speed low-torque region which is preferable for long-haul electric trucks. Balance is achieved between copper and iron-core losses during steady-speed intervals of the test cycles which leads to minimum losses in total

Global Convergence of Online Identification for Mixed Linear Regression

Mixed linear regression (MLR) is a powerful model for characterizing nonlinear relationships by utilizing a mixture of linear regression sub-models. The identification of MLR is a fundamental problem, where most of the existing results focus on offline algorithms, rely on independent and identically distributed (i.i.d) data assumptions, and provide local convergence results only. This paper investigates the online identification and data clustering problems for two basic classes of MLRs, by introducing two corresponding new online identification algorithms based on the expectation-maximization (EM) principle. It is shown that both algorithms will converge globally without resorting to the traditional i.i.d data assumptions. The main challenge in our investigation lies in the fact that the gradient of the maximum likelihood function does not have a unique zero, and a key step in our analysis is to establish the stability of the corresponding differential equation in order to apply the celebrated Ljung's ODE method. It is also shown that the within-cluster error and the probability that the new data is categorized into the correct cluster are asymptotically the same as those in the case of known parameters. Finally, numerical simulations are provided to verify the effectiveness of our online algorithms

Multi-point and multi-objective optimization of a centrifugal compressor impeller based on genetic algorithm

The design of high efficiency, high pressure ratio, and wide flow range centrifugal impellers is a challenging task. The paper describes the application of a multiobjective, multipoint optimization methodology to the redesign of a transonic compressor impeller for this purpose. The aerodynamic optimization method integrates an improved nondominated sorting genetic algorithm II (NSGA-II), blade geometry parameterization based on NURBS, a 3D RANS solver, a self-organization map (SOM) based data mining technique, and a time series based surge detection method. The optimization results indicate a considerable improvement to the total pressure ratio and isentropic efficiency of the compressor over the whole design speed line and by 5.3% and 1.9% at design point, respectively. Meanwhile, surge margin and choke mass flow increase by 6.8% and 1.4%, respectively. The mechanism behind the performance improvement is further extracted by combining the geometry changes with detailed flow analysis

Some properties of solutions for a class of metaparabolic equations

In this paper, we study the initial boundary value problem for a class of metaparabolic equations. We establish the existence of solutions by the energy techniques. Some results on the regularity, blow-up and existence of global attractor are obtained

Energy Efficiency Comparison of Hybrid Powertrain Systems for Fuel-Cell-Based Electric Vehicles

Fuel cell electric vehicles have great superiorities in endurance mileage, charging speed and climate tolerance compared to battery electric vehicles. However, a supercapacitor or battery bank is required to maintain a fast-dynamic response, which leads to several hybridization structures for fuel-cell-based electric vehicles due to the unique characteristics of each device, and their performances are also differing. The purpose of this paper is to provide a comprehensive comparison of hybrid powertrain systems for three types of powertrains: fuel cell/supercapacitor passive hybrid, fuel cell/supercapacitor semi-active hybrid, and fuel cell/battery semi-active hybrid. Each powertrain component model is developed from the real components wherever possible, and Honda FCX Clarity fuel cell vehicle is studied as the benchmark. The powertrain energy efficiency under Worldwide harmonized Light vehicles Test Cycle (WLTC) is analyzed and evaluated. The simulation results show that three powertrains have the same energy consumption, and fuel cell/supercapacitor passive hybrid powertrain increases the system efficiency by 2% and 4% in propulsion and regenerative braking, respectively. By contrast, the other two powertrain topologies have similar performance in terms of energy efficiency