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The SHPB loading three-point bending specimen is a popular way for measuring the dynamic fracture toughness of the material. The wedge shapes on the loading end of the incident bar have necessary effects on the propagation of the stress wave. The dynamic mechanical response and the fracture toughness of the aluminum alloy were measured by SHPB with different wedge shapes, and the influences of wedge shape on determination of dynamic fracture toughness was analyzed in this study. The investigation result can be used to provide reference for the design of a new Hopkinson apparatus for dynamic fracture testing.

Modified Hopkinson pressure bar apparatus is widely used to investigate the dynamic fracture behavior of materials at higher rate loading. While using a small sample for fracture toughness testing, plane strain conditions are compromised. In the current work, a large diameter two-bar/ three-point bend fracture setup is used to analyze stress wave propagation behavior within a larger cracked specimen. The experimental setup model consists of striker, incident bar, loading pin, cracked three-point specimen, span and transmission bar. The model is prepared using ANSYS software and the transient dynamic analysis technique is used to simulate the dynamic load. The effects of increased transient time on the stress wave propagation behavior within the cracked sample and the stress and strain values at the crack tip of the three-point bend specimen are analyzed. In addition, the effects of the hollow striker, the hollow incident bar and the specimen span are studied. It is found that during large specimen testing, an increase in the transient time results in the lower stress and strain values in the specimen crack-tip. The relationship of the specimen span, the striker and the incident bars with the strain values in the specimen is analyzed and a method for the three-point bend specimen testing at the higher strain rates is also proposed.

Mechanical model and simulation model of shaper quick-return mechanism are introduced based on ADAMS. The number of rigid bodies is reduced by using composite joints constraint . It doesn’t need any other softwares and data interfaces in the simulation.The results prove the correctness of the simplified model.It improves the design efficiency and speed of simulation and provides a theoretical basis for the design and analysis of other six-bar mechanism.

The paper digs out useful conclusions for businesses from the mass of product reviews. To conduct commodity pricing, merchandise improvements provide a basis so as to promote sales performance. The paper discusses the product reviews of emotional connotation. It summed up the current situation development of emotional analysis on product reviews. It analyzes the significant commercial value of product reviews. Product reviews explores the relationship between emotion and sales performance analysis. We can research the technical implementation process of reviews.

The dynamic behavior assessment of material is very important before selecting the material for structural applications. In the modern world, Modified Hopkinson pressure bar apparatus is being widely used to investigate the dynamic behavior of engineering materials under compressive and tensile loading. Materials like ceramics, rocks, metals, concrete and soft material are being tested. The cost associated with the dynamic loading pressure bar apparatus are also low and can be easily built. For accurate measurement of material properties we need to understand the basic concepts associated with dynamic loading. With the advancement in computational capabilities, the dynamic load testing of materials is also performed in available commercial software's. In the current work, the basic concepts and components associated with dynamic compressive loading system are discussed and a test case studies are also selected for analyzing material specimen behavior during testing. For simulation of dynamic compressive loading ANSYS LS-DYNA software is used and the output of the simulation results is analyzed. The effects of changing the diameter of material specimen, and hollow bars on stress and strain values in the bar and setup are also discussed.

Saas is an abbreviation for Software-as-a-service, it is a completely innovative software application mode provided via Internet. As a new IT service model, SaaS has two sides. This article focuses on analysis the existent security risks of SaaS and put forward a series of countermeasures and suggestions to address these issues from the technical aspects.

At higher loading rates, modified Hopkinson pressure bar apparatus is widely used to determine the dynamic fracture toughness of the engineering materials. For accurate measurement of the dynamic fracture properties, we need to thoroughly understand the contact situation of the three-point bend specimen, with the loading apparatus. Strong inertial effects complicate the specimen’s contact situation with impactor and supports. In this work, ANSYS software is used for modeling and analysis of a modified Hopkinson pressure bar loaded fracture experimental setup. Analysis of stress contours and nodal displacements are used for the examination of specimen contact state. The results indicate that during loading in the elastic range, the specimen remains in contact with the loading apparatus as this is previously proved experimentally.

Hopkinson pressure bar apparatus is extensively used for the measurement of the dynamic fracture properties. For accurate measurement of the dynamic fracture properties we need to understand concepts and principles associated with the test setup. The understanding of stress wave in the bar and specimen is also very important. In the current work, ANSYS LS-DYNA software is used to simulate the propagation behavior of the time based loading and generation of stress wave. The stress and strain plots in the specimen and the incident bar are obtained as an output of the analysis. The analysis of the plots suggest that, for the same time duration the rising trend is observed for the plots of stress and strain of incident bar whereas a sine wave trend is observed for the plots in the specimen.

For the Comprehension of the dynamic mechanical properties of the materials under the dynamic loading, Hopkinson pressure bar apparatus is used. During the compression testing of the low impedance materials the use of the hollow transmission bar is common. In the current work, the analysis is performed to analyze the effects of hollow transmission and incident bars on the specimen testing for the large diameter compression setup. Complete model of the setup is prepared using the ANSYS software and the simulation of loading is done using the LS-DYNA software. The results of analysis indicate that for the large compression testing setup, solid bars can be replaced with hollow bars. By using the hollow transmission bar the objective of high strain rate testing is also obtained.

For managing water resources, rationalizing consumption structure is the key issue. In daily life, the faucet is the most common as well as the most likely to be neglected manner to use water. At present, faucets in the market are not so diverse. In some cases, the effects of pressure on the flow of water have been ignored, although they may be multifunctional. Through modifying pressure, controlling water flow can not only enhance the rational use of water resources but also increase the service life of the faucets. The results show that this kind of faucet with the function of depressurization and throttling is very worthy of applying and introducing.

SMS has been widely used in College Students. SMS has a significant impact on students’ minds, learning and life. In order to improve education quality, higher education workers should give full play to the the characteristics and functions of SMS. The features of SMS applied in higher education were analyzed. The important role of SMS applied in higher education was discussed. The application methods of SMS applied in higher education were put forward.

Based on the Swarm platform and adaptive multi-agents of complex system, the simulation model of mobile telecommunications market’s regulation has been developed with the aim to simulate the effects of regulatory policies. Through the different simulation results, the implementation of regulatory policies having impact on the mobile telecommunications market can be analyzed, which provides theoretical support and basis for the future development of mobile telecommunications market’s regulatory policy, in order to avoid the unpredictable and potential risk of the regulatory policies in the effective implementation process.

Late Launch, which is a kind of dynamic measurement technology proposed by both Intel and AMD, offers isolated execution environment for codes needed to be protected. However, since the specifications and documents of Late Launch have hundreds of pages, they are too long and complicated to be fully covered and analyzed. A model based on Horn clauses is presented to solve the problem that there is a lack of realistic models and of automated tools for the verification of security protocols based on Late Launch. A running example is taken to show the execution details of Late Launch. Based on the example, secrecy properties of Late Launch are verified. Whats more, the automatic theorem proving tool ProVerif is used to make the verification more fast and accurate.

According to the experiments study of sulfuric acid saline soil, the formula of compression coefficient with the changes of moisture content, salt content, initial dry density and temperature is presented, and the law of single influencing factor on sulfuric acid saline soil compression are analyzed in the paper.

According to the experiments study, the formulas of strength with the changes of moisture content, natural dry density, cement dosage are presented. Applicable range of cement mixing pile to consolidate soft soils is determined which can be used to guide the using of cement mixing pile and provide reference for design or research departments at the same time.

In order to obtain characteristic parameters of the debris from accident pictures for traffic accident reconstruction, MATLAB image processing technology was applied to deal with accident pictures such as grayscale transformation, binarization, noise reduction and segmentation. According to the proportional relationship obtained by camera calibration between pixel and the actual size, the diameter of sphere debris, the length and width of rectangular debris were achieved. The error calculated by comparing extraction parameters of accident picture with real size is within 5%.

The dynamic fracture behavior of 7075-T6 aluminum alloy was studied by finite element method to simulate a cracked three-point bending specimen loaded by stress wave loading. In order to determine the elastic-plastic dynamic fracture toughness using quasi-static fracture mechanics theory, the nominal load measured by Hopkinson pressure bar loaded fracture testing system was input into a finite element program to calculate the loading point displacement, and then this displacement was employed to obtain the load-displacement field in the vicinity of the crack tip without the inertia effect, the variation of J-integral as a function of time was established using the load-displacement parameters determined by finite element analysis. The critical J-integral corresponding to crack initiation time detected by a small strain gauge mounted on the three-point bending fracture specimen is determined as an elastic-plastic dynamic fracture toughness (JId). The comparison between the equivalent dynamic fracture toughness(KId) given by the aforementioned procedures and the value measured in previous studies was made to verify the validation of the proposed procedure.

Some fundamental issues, such as stress wave dispersion effect, loss of contact, pulse shaping effect are still needed to thoroughly understand in Hopkinson pressure bar loaded fracture experimental techniques. In order to avoid the influence of stress wave dispersion on the analysis of dynamic experimental results, a computational procedure has been developed based on the combined analytical solution of Pochhammer-Chree with Fourier spectroscopy analysis. The validity of this proposed computational procedure was confirmed via the comparison with the experimental stress pulses obtained from pulse-shaped tests. The experimental results can be easily interpreted and the testing accuracy can be improved using this computational procedure.

In this paper, solar thermal utilization methods in hospitals, schools, hotels and factories in a typical Southern China city, e.g., Dongguan City, were investigated, which lead to the understanding of the heating methods in different types of buildings and the application ratio of different kinds of renewable heating systems, e.g., solar water heater, in all kinds of buildings. These will help reveal the usage of renewable energy for heating and its development in this region of China.

This paper studied the thermal and physical properties of a new solar solid desiccant material, including the equivalent thermal conductivity under different moisture content conditions and penetrability under different simulated solar radiation. The results showed that the equivalent thermal conductivity of the material was related to the moisture content and water saturation. In unsaturated state, the equivalent thermal conductivity increased with the increase of the moisture content and presented a linear relation in certain range. When reached saturation, the equivalent thermal conductivity decreased with the increase of the moisture content. These figures could provide the basis for the determination of the thickness of the dehumidification bed and optimization of the design of the dehumidification system.

The SiC/Cu composite is one of the "structural-functional" materials. It shows good mechanical properties and very high thermal, high electrical conductivity etc. But the co-dispersion, wetting and bonding between SiC and Cu interface are of practical importance in the preparation of SiC/Cu composites. In this work, surface treatment techniques such as high-temperature oxidation, acid dipping and alkaline wash were adopted separately on silicon carbide particles, in order to improve the wettability and physical and chemical compatibility between silicon carbide and copper, then we used the replacement reaction method and decomposition-reduction reaction method to generate Cu coating on the surface of silicon carbide. The results shown that, the surface of silicon carbide particle which treated by alkaline wash was cleaner and more rough than that only treated by high-temperture oxidation, moreover, the specific surface of the particle was increased, which resulted in a compact layer of Cu coating. for the same silicon carbide particles, the effect of the Cu coating prepared by decomposition reaction method was better than that by reduction reaction method.

CBN particles coated with borosilicate glass-aluminum composite coating (Glass-Al-CBN) were prepared by a multilayer coating method. The coated composite particles were sintered at 800°C for 2h. XRD, DTA-TG, SEM techniques were used to characterize the samples. It was found that AlN was formed by the reaction of Al and CBN. The mechanical properties and the oxidation resistance of the composite was improved due to the presence of the glass coating and alumina.

Cloud computing is an important innovation of current computing models. At present, the research on the security of cloud computing is mainly concentrated on PCs and servers. The security of embedded system in cloud environment does not win enough attention. This paper analysis the security threats of it, and proposes a Secure Hardware Model to provide a tamper-resistant and more reliable hardware embedded platform in cloud environment. Our model adds some new components to traditional embedded system, controls the start sequence of platform’s components, verifies the integrity of crucial information for embedded platform and recovers the system if necessary. Our implementation demonstrates the feasibility of Secure Hardware Model, it enhance the secure and reliable boot of embedded system. With the constant development and application of embedded system in cloud computing field, our research will influence cloud computing greatly.

The cosine solution of the Fick-2 Law, which was considered as the mathematical model of homogenization of dendritic segregation, has always been used to analyze high temperature diffusion. Cosine solution can not exactly describe the actual distribution of alloying elements in dendrite, as the slope of cosine curve is quite gentle. Based on segregation ratio SR, a new mathematical model was established by using Gauss solution of the Fick-2 Law. The new model could describe the evolution of homogenization of alloying elements during the process of high temperature, which was proved by some specific examples.

Biocompatible MgAl-CO3-LDH-derived layered double oxide (LDO) as the host and bovine serum albumin (BSA) as a model protein have been chosen to fabricate a novel bioinorganic nanohybrid (BSA-LDO). The structure, morphology and physicochemical properties of the obtained nanohybrids are investigated by XRD, FT-IR, SEM and UV-vis methods and the interaction between LDO and BSA molecules has been discussed. The application of these nanohybrids as drug carrier is primarily studied by examining the adsorption behaviors of three drugs.

This paper expects to get the real-time changes of traffic flow by researching the relationships among the three basic parameters flow, speed and occupancy. we firstly carries out the statistical correlation analysis and grey relational analysis to study the connection between the traffic flow parameters flow and speed, flow and occupancy to get a conclusion that there doesn’t exist a significant linear relationship between neither of the comparisons, and the influence of speed on the flow is a little bigger than that of occupancy. Then we try to establish the binary linear regression model without the intercept and GM (0,3) model to do the data fitting, the final simulation results illustrate that the two methods has effects in some extent, also explain the complexity of traffic flow.

The complex tower structure appears as modeling of palms together, which is designed as steel frame-core tube structure. This paper uses SAP2000 to analysis seismic response respectively on the linear and elastic-plastic stage, and puts forward some specific suggestions for seismic design according to the analysis and calculation.

Common digital differential analyzer（DDA）linear interpolation error is lower than a pulse equivalent, and the output pulse along each axis is not uniform. New DDA linear interpolation flow chart was obtained by combining a quick algorithm of DDA interpolation and interpolating algorithm for pulses uniformization with common DDA linear interpolation principle. The relationship between interpolation error and pulse equivalent was demonstrated in detail. As the results shows, the new DDA with high precision machining but simple algorithm, increased interpolating speed; the new algorithm make the generation of uniform pulse series come true, which is of great importance to keep stepping motor rotating steadily without missing steps; At coordinate origin, interpolation error is lower than 0.42 pulse equivalent, while the interpolation point is not at coordinate origin, interpolation error is lower than 0.5 pulse equivalent.

To understand more about Lamb waves on composite laminates damage detection features, the Lamb wave group velocity dispersion curves are calculated and plotted by using dichotomy method in MATLAB. The signal parameters are chosen according to Group velocity dispersion curves. The dynamic response signals of the composite plate are obtained by finite element method. Damage location is calculated by the actual group velocity of Lamb wave and time of flight of the difference signal before and after damage.

The effect of specimen overhang on contact state between specimen and supports has been investigated by analyzing stress wave propagation in loading bar, specimen, and supports in Hopkinson bar. The results show that the time for loss of contact decreases with increasing overhang. The criterion is obtained for keeping the specimen contact with supports under a fixed of the specimen thickness and width.

Compared to other spinning system, the ring spinning process has been used to produce higher quality yarns, but with a much lower spinning efficiency, resulted from the relatively high spinning tension that leads to increased yarn breakage rates and makes high power consumption. Thus, depressing yarn tension is essential to change the status. In this paper, we design a movable balloon controller system to reduce yarn tension. The system is automatic, composed of powder switch, touch screen, PLC (Programmable Logic Controller), pulling-thread displacement sensor, controller of step motor, step motor and linear module. PLC, the core of the system, controls the position of the balloon controller by a series of programs. Then yarn tension was tested while spinning with movable balloon control ring, fixed balloon control ring and no balloon control ring, respectively. The result shows that the yarn tension can be depressed indeed by equipping this movable balloon controller system to some extent. Additionally, we find that the number of hairiness of ring spun yarns with this system can be reduced to some extent, while yarn tensile properties are not as sensitive to be worse. It is significant to cut down ends-down rate, improve the quality of ring spun yarns, the spinning efficiency as well as the energy efficiency of ring spinning.

The effect of specimen width on the contact state between the three-point bending (TPB) specimen and supports has been investigated with the apparatus of Hopkinson pressure bar using the analysis method of the propagation of stress wave. The results indicate that, the time for loss of contact decreases linearly with the increase of specimen width when the specimen width is less than a critical value, and the relationship between the time for loss of contact and the specimen width shows a parallel line to the abscissa when the specimen width is greater than the critical value.

Sensor data are the basis for health assessment of complex structural systems. Careful selection and logical layout of sensors is critical to enable the high reliability of system health assessment. This paper presents a methodology how to use a minimum number of sensors, and what locations of them should be placed, so that the voltage signals received from the sensor can be used to detect both presence and extent of damage. In this study, an optimization procedure is developed using Genetic Algorithm (GA) to determine the location of piezoelectric sensor for damage detection in a composite wingbox. A new damage index using all differences in voltage signals decomposed by wavelet transform is proposed. Results show that the proposed method is available at determining number and location of sensors for structural damage detection using piezoelectric patch sensors.

The paper presents an effective damage detection method of complex composite structures. It can be carried out through the experimental modal analysis of the damaged structure. The method using the improved Cross Modal Strain Energy (CMSE) technique and Niche GA has many advantages compared with other damage detection methods. The CMSE method can use any modes of the structure and the modes don’t need to be normalized or consistent in scale. The Niche GA improves the efficiency of the calculation and enhances the capacity of identifying structural damage localization. The model is the composite material airfoil case. The numerical results show that the method proposed in this paper is successful for damage detection of complex structures.

A vibration-based approach to detect crack damage in a cantilever composite wingbox is studied using the improved Hilbert-Huang Transform (HHT). The improved HHT is composed of HHT with Wavelet Packet Transform (WPT) and a simple but effective method for intrinsic mode function (IMF) selection. For different damage status, in order to obtain structural dynamic responses, which imply plentiful damage information, the composite wing boxes were excited by a contrived square wave signal. Then, the dynamic responses of intact wingbox and damaged wingbox are disposed using improved HHT. Finally, a feature index vector of structural damage, i.e. the ariation quantity of instantaneous energy, is constructed. The obtained results show that the proposed damage feature index vector is more sensitive to small damage than those in traditional signal processing.

Among many user authentications over insecure networks, password authentication is simple, convenient and widely adopted one. Chen and Lee proposed a new hash-based password authentication using smart card and claimed that their scheme could resist seven attacks as listed in their paper. However, in this paper, it is pointed out that Chen-Lee’s scheme is vulnerable to off-line password guessing, replay and impersonation attacks when the smart card is lost or stolen.