Development,modeling and application of piezoelectric fiber composites

Piezoelectric materials are capable of actuation and sensing and have been used in a wide variety of smart devices and structures.Active fiber composite and macro fiber composite are newly developed types of piezoelectric composites,and show superior properties to monolithic piezoelectric wafer due to their distinctive structures.Numerous work has focused on the performance prediction of the composites by evaluation of structural parameters and properties of the constituent materials with analytical and numerical methods.Various applications have been explored for the piezoelectric fiber composites,including vibration and noise control,health monitoring,morphing of structures and energy harvesting,in which the composites play key role and demonstrate the necessity for further development.

用平均值不等式求极值的配凑技巧

文章应用平均值不等式x+y≥2(xy)~1/2(x】0,y】0)求极值的一些常用技巧。

Effects of cold deformation on microstructure and mechanical properties of Ti-35Nb-2Zr-0.3O alloy for biomedical applications

The Ti-35Nb-2Zr-0.3O(mass fraction,%)alloy was melted under a high-purity argon atmosphere in a high vacuumnon-consumable arc melting furnace,followed by cold deformation.The effects of cold deformation process on microstructure andmechanical properties were investigated using the OM,XRD,TEM,Vicker hardness tester and universal material testing machine.Results indicated that the alloy showed multiple plastic deformation mechanisms,including stress-inducedα'martensite(SIMα')transformation,dislocation slipping and deformation twins.With the increase of cold deformation reduction,the tensile strength andhardness increased owing to the increase of dislocation density and grain refinement,and the elastic modulus slightly increasedowing to the increase of SIMα'phase.The90%cold deformed alloy exhibited a great potential to become a new candidate forbiomedical applications since it possessed low elastic modulus(56.2GPa),high tensile strength(1260MPa)and highstrength-to-modulus ratio(22.4×10-3),which are superior than those of Ti-6Al-4V alloy.

Direct extrusion of thin Mg wires for biomedical applications

Biodegradable wires,able to provide load-bearing support for various biomedical applications,are the novel trends in current biomaterial research.A thin 99.92%Mg wire with a diameter of 250μm was prepared via direct extrusion with an extreme reduction ratio of 1:576.The total imposed strain in a single processing step was 6.36.Extrusion was carried out at elevated temperatures in the range from 230 to 310℃and with various ram speeds ranging from^0.2 to^0.5 mm/s.The resulting wires show very good mechanical properties which vary with extrusion parameters.Maximum true tensile stress at room temperature reaches^228 MPa and ductility reaches^13%.The proposed single-step direct extrusion can be an effective method for the production of Mg wires in sufficient quantities for bioapplications.The fractographic analysis revealed that failure of the wires may be closely connected with inclusions(e.g.,Mg O particles).The results are essential for determining the optimal processing conditions of hot extrusion for thin Mg wire.The smaller grain size,as the outcome of the lower extrusion temperature,is identified as the main parameter affecting the tensile properties of the wires.

Advanced yolk-shell nanoparticles as nanoreactors for energy conversion

Yolk‐shell structured nanoparticles are of immense scientific and technological interests because of their unique architecture and myriad of applications.This review summarizes recent progresses in the use of yolk‐shell structured nanoparticles as nanoreactors for various chemical reactions.A very brief overview of synthetic strategies is provided with emphasis on recent research progress in the last five years.Catalytic applications of these yolk‐shell structured nanoreactors are then discussed by covering photocatalysis,methane reforming and electrochemical conversion.The state of the art research and perspective in future development are also highlighted.

Development of Palm Oil Based Bio-product Industrial Wax and Its Application Performance Study

Machining is a mechanical process where excess material from a work is removed to produce a product. At the moment different ferrous, non-ferrous materials and industrial blue wax have been used for prototype models. However such materials is very expensive. Hence an attempt is made to substitute these materials by the palm oil based bio-wax produced in Malaysia. In this research, the authors will analyze and investigate whether there is a possibility to use the palm oil based bio-wax material to substitute with the petroleum based industrial-wax. Experimental analyses are carried out to investigate the capability and the strength of the palm oil based bio-wax material. The matrix blends were prepared of fatty acids from oleo-chemicals, palm oil wax, natural ash fibre and low linear density polyethylene （LLDPE） by stirring and melt-mixing. Sample b!ends are machined with lathe machining process. The sample blends showed there was no built edge formation and good smooth surface production.

Compact Electric Energy Storage for Marine Vehicles Using on-Board Hydrogen Production

The use of electric energy in marine vessels has been increasing in recent years. In general, it is motivated by the low ecological impact. However, in the case of underwater vehicles it is functionally essential. The objective of this study is to demonstrate the advantage of electric power generation and storage based on on-board hydrogen generation via the reaction between activated aluminum and water and application of the hydrogen in a fuel cell. The original activation process enabling a spontaneous reaction with water to produce hydrogen as well as a parametric study of hydrogen generation rate and yield are briefly described. The potential increase in specific energy （energy per unit mass） and energy density （energy per unit volume） vs. batteries and other means of hydrogen storage is presented. It is shown that the use of the present technology may result in a substantial increase of specific electric energy along with a reduction in volume or an increase in operating time for the same overall mass of energy storage and generation system.

De-polymerization of Waste Polymers to Produce Hydrocarbon Fuel Utilizing Thermal Degradation

Waste plastics are one of the biggest environmental concerns the world faces today. Waste plastics exposure to the environment is very hazardous. Over time waste plastics photo-degrade and become very tiny dust particles. These dust particles contain very harmful compounds including benzene, sulfur, carbon and many others. According to studies, waste plastic pollutions are one of the biggest reasons for the depletion of the ozone layer and contributor of global warming. Many scientists have been trying to figure out how to utilize these waste plastics and convert them into useful energy sources. It is possible to convert waste plastics into energy because they are made from petroleum. Scientists have succeeded in developing many methods including pyrolysis, catalytic cracking, thermal degrading and others. The purpose of this experiment is to convert these environmentally harmful waste materials into useful energy source using simple and viable methods. A particular thermal degradation process was successful in extracting fuel from waste plastics at 370-420 ~C. In this paper we will discuss our performed experiment and provide detailed analysis of the produced fuel. Thorough instrumental analysis of the produced fuel showed very considerable results including high energy contents, low levels of harmful emissions and compatibility with various types of existing appliances.

High-Volume Fly Ash Concrete-A Relevant Step to Sustainable Development

HVFA （high-volume fly ash） concrete could be a sustainable way for by-product utilization to conserve natural resources and protect environment. HVFA concrete can play the role of a high-performance material that may be comparable to the conventional Portland cement concrete. The results of the research programme concerning the relationships between the composition of concrete （w/b ratio, fly ash content and type of cement） and their physical and mechanical properties are presented and discussed in the paper. It is found that the introduction of high-volume fly ash into concrete has caused a decrease in compressive strength at the early age of storage. The significant increase in strength was observed between 28 days and 90 days of curing. The high-volume fly ash concretes were characterized with lower water absorbability and sorptivity than control concrete.

The Application of Schema Theory to English Reading Teaching in Junior High School

Reading is an effective means to cultivate junior high school students＇ comprehensive ability of using English and plays an important role in English study. Schema theory is a scientific reading theory advocated by modern teaching, and it regards the reading comprehension as a process that readers＇ knowledge and skills interact with the information in the reading material. In this paper, a questionnaire is conducted to reveal the fact that students lack schemata in reading and then a proposal that language schema, content schema, and form schema be integrated to activate students＇ existing schemata in the process of reading is put forward

Soil Removal Efficacy of Catholyte on Polyamide 6.6 Fabric

This study determined the detergency properties of Catholyte, an electrochemically activated medium, on polyamide 6.6 as a possible alternative to conventional laundering detergents. Undyed polyamide 6.6 was used and soiled with keltex, corn starch, mineral oil, oleic acid, morpholine, vegetable fat, butanol, solvesso 150 and water. Some soiled fabric was retained as control and not laundered. Soiled fabric was laundered at 30 ~C as well as 40 ~C with either, distilled water, Catholyte, non-phosphate detergent, a 50/50 solution of Catholyte and non-phosphate detergent, or a 50/50 solution of Catholyte and phosphate detergent. Data were analyzed descriptively by using analysis of variance （ANOVA）, which fitted the factors of treatment and temperature, as well as all two-factor interactions between these variables. A probability value of 0.05 or less indicated significance. Catholyte was effective in removing soil and reached a/XE＊ value of 59.30, but was statistically different from the phosphate detergent. Temperature did not have a significant effect on soil removal from the fabric, but the interaction with a treatment had significant effects. Treatment alone had a significant soil removal effect on the fabric. Thus, the temperature was dependent on an interaction with the treatment. The non-phosphate detergent was efficient in removing soil from the fabric and slightly more efficient than either 50/50 Catholyte solution. The 50/50 Catholyte/non-phosphate detergent solution was slightly less effective than its phosphate containing counterpart. When considering the interaction between treatment and temperature, the 50/50 Catholyte/phosphate and 50/50 Catholyte/non-phosphate solutions were more efficient at 40 ~C. Thus the interaction between the solution and higher temperature proved to be a better combination. This was also the case for the Catholyte and the non-phosphate wash liquors. Catholyte, an environmentally friendly washing agent, is an attractive alternative to conventional laundry detergents because it removes soil efficiently from polyamide 6.6 fabric.

Exploration and practice of English teaching in Stomatology

Stomatology English as an international language in the academic field, it is the basic skill that oral medicine students uses to understand the academic from, master new technologies in clinical, and expand professional horizons. The study targets for the training the ability of applying stomatology English, exploring and practicing in the teaching materials, teacher training, teaching methods and the language application environment, thus forming a ＂three-step＂ stomatology English teaching mode and gaining effective results.

Examples ofhigh-tech materials applied in sports equipment

This paper briefly introduces the application of new materials in sports and effect on sports performance, points out that development of competitive sports in the process, must pay attention to the development and utilization of new materials, development.

Effect of Soil Strength and Soil Physical Properties on Performance of Tillage Machines

Soil parameters have significant influence on the performance of tillage machines for various kinds of tillage operations, such as soil movement by tillage tool, soil cutting, soil turning, soil pulverization, and manure injections, etc. This paper attempts to provide a clear overview of soil physical properties and soil strength, and their effects on the performance of tillage machines. Furthermore; it includes the descriptions and characteristics of these parameters, and last developed equipment and procedure for evaluating and assessing of these parameters.

Compensatory growth response of rainbow trout Oncorhynchus mykiss Walbaum following short starvation periods

This sixty-day study was performed to determine the effects of short-term starvation and refeeding cycles on growth, feeding performances and body composition of rainbow trout （Oncorhynchus mykiss）. Three hundred trout fingerlings with an average initial weight of 17.54-0.06 g were randomly distributed in 15 circular fiberglass tanks. The fish were exposed to 5 different feeding regimes; control： continuously fed twice daily to apparent satiation; T1： starved for 1 day and re-fed for 2 days; T2： starved for 1 day and re-fed for 4 days; T3： starved for 3 days and re-fed for 12 days; T4： starved for 4 days and re-fed for 16 days. At the end of the experiment, growth performance, feed utilization, whole body ash and moisture contents were not significantly （P〉0.05） different among the treatments. However, whole body protein content in T3 was significantly higher than other treatments （P〈0.05）. A significant difference in whole body fat content was observed between T3 and the control group at the end of the experiment （P〈0.05）. In conclusion this experiment suggests that feeding schedules involving starvation （1-4 days） and re-feeding cycles are a promising feed management tool for rainbow trout culture.

Primary Study on Microarc Oxidation of AZ91D

The magnesium has some excellent properties such as ligh quality, high specific strength and stiffness, high damp and reeoverd easily compared with steel, aluminium, engineering plastic. So the application and exploitation of magnesium arose extensive attention of the public.

Production Performance of Broiler Chickens Fed with Silkworm Pupa （Bombyx mon~

The production performance of broilers fed with silkworm pupa （Bombyx mori） was studied by focusing on growth, feed utilization, carcass composition and meat quality. There were two difference sources of silkworm pupa： （1） silkworm pupa from spun silk industry （SSP） and （2） silkworm pupa from silk yam reeling industry （RSP） were mixed into five isonitrogenous （20% CP） and isocaloric （ME = 3,150 kcal/kg feed） diet. The 195 chickens at three weeks old were equally distributed to 15 pens in the closed housing. The experiment was divided into five dietary treatments （three replications each）： treatment 1 （10% fishmeal, FM and 0% silkworm pupae） （control））, treatment 2 （0% FM and 10% SSP）, treatment 3 （0% FM and 20% SSP）, treatment 4 （0% FM and 5% SSP ＋ 5% RSP）, and treatment 5 （0% FM and 10% SSP ＋ 10% RSP）. Daily weight gain was 0.069, 0.060, 0.051, 0.065 and 0.061 kg/chick in treatments 1, 2, 3, 4 and 5, respectively. It is indicated that replacing fishmeal with silkworm pupa （5%SSP ＋ 5%RSP） performed the same daily weight gain as control but exhibited the higher feed conversion ratio （1.87） than control （1.68）. Carcass muscle of control treatment 1 （58.26%） was the highest （P 〈 0.05） and closed to treatment 4 and 5 （57.62% and 57.83%, respectively）. Sensory evaluation was not significantly differences （P 〉 0.05）. Therefore, treatment 4 （5%SSP ＋ 5%RSP） could be substituted FM with little adverse effect on broiler growth but without any adverse effect on percentage of muscle and sensory test. However, further supplemental silkworm pupa performed reduction in dietary utilization and carcass muscle.

A new generic reaction for modeling fluid catalytic cracking risers

A new generic reaction in the form of PC_i→PC_m+[i,m]→PC_m+λi,m coke+surplusage has been proposed for describing the catalytic cracking behavior of petroleum narrow cuts or pseudo-components(PCs),where the rate constant formula is derived from the transition state theory and the coking amount is correlated to the properties of the intermediate substance [i,m].In composing the cracking reaction network for feedstock and product oils,only the product PC m of the proposed generic reaction is used,which together with a criterion for excluding exothermic reactions,distinctly reduces the number of reactions in the network.With the proposed cracking reaction scheme coupled with special pseudo-components,a predictive one-dimensional steady state model for fluid catalytic cracking risers is formulated in the sense that for a given riser and given catalyst,the model parameters are independent of stock oils,product schemes and other operational conditions.The great correlating and predicting capability of the resulted model is tested with production data in different scenarios of four commercial risers.

Analysis of the Power System from an Electron Beam Accelerator and the Correlation with the Theoretical Dosimetry for Radiation Processing

Dynamitron DC1500/25/04 type EBA （Electron beam accelerator）, model JOB 188, was manufactured by IBA Industrial （Radiation Dynamics, Inc.） and installed at IPEN-CNEN/SP, in 1978. The technical specifications of the EBA are： energy 0.5 to 1.5 MeV; beam current： 0.3 to 25.0 mA; beam scanning： 60 to 120 cm; beam width： 25.4 mm and frequency： 100 Hz. Nowadays, this accelerator has been used for innumerable applications, such as： For sterilization of medical, pharmaceutical and biological products, treatment of industrial and domestic effluents and sludge, preservation and disinfestations of foods and agricultural products. Other important application are lignocellulosic material irradiation as a pre-treatment to produce ethanol bio-fuel, decontamination of pesticide packing, solid residues remediation, organic compounds removal from wastewater, treatment of effluent from petroleum production units, crosslinking of foams, wires and electric cables. Electron accelerator JOB 188 is, also, very important composite and nanocomposite materials and carbon fibers irradiation, irradiated grafting ion-exchange membranes for fuel cells application, natural polymers and multilayer packages irradiation and biodegradable blends production. The energy of the electron beam is calculated as a function of the current in the accelerator high-voltage divisor, taking into account the thickness and density of the material to be irradiated. This energy is calculated considering the electron through the entire material and the distance from the titanium foil window, so that the absorbed doses at the points of entrance and exit are equivalent on the material. The dose is directly proportional to the beam current and the exposure time of the material under the electron beam and inversely proportional to the scan width. The aim of this paper is to analyze the power system parameters of the EBA Dynamitron DC 1500/25/04, such as, voltage and RMS （Root-mean-square） current in the oscillator system, high voltage generator and waveform. For this purpose software developed in the Radiation Technology Center at IPEN/CNEN-SP to simulate the energy efficiency of this industrial accelerator. Finally, it is also targeted to compare theoretical dosimetry using parameters of energy and beam current with data from the accelerator power system. This knowledge and technology will be very useful and essential for the control system upgrade of EBA, mainly Dynamitron DC 1500/25/04 taking into consideration that radiation processing technology for industrial and environmental applications has been developed and used worldwide.

Performance Evaluation of Spark Ignited Engine Fueled with Gasoline-Ethanol-Methanol Blends

In this paper, experimental investigations are presented to assess the performance variations in a single cylinder spark ignited engine when run with three different gasoline-alcohol blends： （88% gasoline-12% methanol, 88% gasoline-12% ethanol and 88% gasoline-6% methanol-6% ethanol）. Additional tests are carried out with the basic gasoline fuel for comparison analysis and performance assessment. Engine performance is investigated under a variety of engine operating conditions. The results are presented in the domain of engine speed. In particular, the brake power of the engine is shown to be slightly increased. The brake thermal efficiency showed an increase compared with the basic gasoline engine. Similarly, it is shown that brake specific fuel consumption is enhanced compared with basic gasoline engine. The exhaust gas temperature showed a decrease compared with gasoline fuel which is preferable to reduce emissions. The alcohol additives are strongly recommended to enhance performance, increasing the mileage and reducing the emissions.