The Formula of Dependence of Mechanical Characteristics of Materials on Crystalline Phase Composition in the Matrix

Objective: For materials science and generally, for long-term operation of work-pieces in industry the significant role is attributed to dependence of macro-mechanical properties of consolidated body on crystalline phase composition, its dimensions, form, distribution in matrix and the form factor. While working in responsible fields of technology of ceramics and ceramic composites the above referred properties are attributed extremely great role with the view of durability and endurance at the terms of heavy mechanical loads. For description of the resistance of any concrete type work-piece, the crystalline phase plays the greatest role in mechanical strength or deformation of any material. It plays the important role in correlative explanation of materials mechanics and matrix properties. In our case, in the process of destruction of ceramic materials and composites, which will give us exhaustive response to the role of macro- and micro-mechanical properties of materials, the role of a macro- and micro-structural component, that is, of crystalline phase in the process of transition of stable state of materials into meta-stable state is extremely big. Our study aims to develop a formula of dependence of macro-mechanical properties of ceramic and ceramic composites on crystalline phase, the most powerful component of their structure, which will enable theorists and practitioners to select and develop technologies and technological processes correctly. Method: On the basis of the study of micro- and macro-mechanical properties of ceramics and ceramic composites and the morphology of crystalline phase and the analysis of the study we determined and created parameters of the formula. Results: The formula covers macro-mechanical properties, that is when the work-piece is thoroughly destructed: mechanic at bending at three and four-point load, mechanic at contraction;among morphological characteristics: composition of crystalline phase and their spreading in matrix, their sizes, form factor;correlative dependence of the above listed properties. Absolutely new definition of a factor of spreading of crystalline phase in matrix is offered. Conclusion: The created formula is of consolidated nature and it can be used in technology of any ceramic material and ceramic composites. The formula will help practitioners to plan correctly and fulfill accurately all positions of technology of production of work-pieces, to carry out the most responsible thermal treatment process of technology of manufacture of work-pieces;to determine correlation between mechanical and matrix properties of materials.

Determination of Tebuconazole Residue in Apples and Vegetables by Matrix Solid Phase Dispersion-Gas Chromatography

[ Objective] The study aimed to determine tebuconazole residue in apples and vegetables using matrix solid phase dispersion-gas chro- matography （MSPD-GC）. [ Method] The effects of extraction and determination conditions on the detection of tebuconazole left in apples and veg- etables were analyzed, and the optimum extraction conditions were determined. [ Result] The recovery rate of tebucenazole was the highest when the ratio of a sample to florisil dispersant was 1 ： 4, and the mixture of hexane and acetone （ 1 ： 1 ） with total volume of 8 ml was as the eluant. Under the optimum conditions, the relative standard deviation （RSD） of the method was 4.9% -7.6%, and the detection limit was 0.1 tJg/g, while the re- covery rate of tebuconazole changed from 86.7% to 95. 2% . [ Conclusion] The method was simple, accurate, sensitive and applicable to the de- termination of tebuconazole in aaricultural Droducts.

Determination of seven active components in Salvia miltiorrhiza herb by matrix solid phase dispersion combined with ion liquid extraction followed by high performance liquid chromatography

A low cost,rapid and sensitive preparation method of silica gel supported ionic liquid(SGSIL)combined with matrix solid phase dispersion(MSPD)followed by high performance liquid chromatography(HPLC)with ultraviolet detection(UV)is proposed,and it was applied to determine the seven active compounds in Salvia Miltiorrhiza herb.SGSIL and ionic liquid[BMIM]BF4 were used as the adsorbent and the green elution reagent in the MSPD procedure.Several extraction conditions including type of filler and elution solvent,the volume of elution solvent,material liquid ratio were optimized.Under the optimum conditions,the SGSIL-MSPD-HPLC method showed a low limit of detection(LOD,S/N=3)of 0.0122-0.8788μg/mL for standard solution,limit of quantification(LOQ,S/N=10)of 0.0406-2.9292μg/mL for standard solution,wide linear range from 1.56 to 2000μg/mL for all compounds for standard solution,correlation coefficients(r)of more than 0.9990,acceptable reproducibility(relative standard deviations,RSDs<3.54%),and precision of RSDs<3.36%for intra-day,RSDs<3.50%for inter-day.The satisfactory recoveries ranged from 96.4 to 102.5,with RSDs less than 3.45%.The developed SGSIL-MSPD method is easier and more suitable for the determination of the seven active compounds in Salvia Miltiorrhiza herb than the traditional ultrasonic extraction.It was an effective and efficient method for the extraction and quantification of the seven active compounds in traditional Chinese herbal samples.

Hybrid Control Strategy for Matrix Converter Fed Wind Energy Conversion System

In this paper, a hybrid control strategy for a matrix converter fed wind energy conversion system is presented. Since the wind speed may vary, output parameters like power, frequency and voltage may fluctuate. Hence it is necessary to design a system that regulates output parameters, such as voltage and frequency, and thereby provides a constant voltage and frequency output from the wind energy conversion system. Matrix converter is used in the proposed solution as the main power conditioner as a more efficient alternative when compared to traditional back-back converter structure. To control the output voltage, a vector modulation based refined control structure is used. A power tracker is included to maximize the mechanical output power of the turbine. Over current protection and clamp circuit input protection have been introduced to protect the system from over current. It reduces the spikes generated at the output of the converter. The designed system is capable of supplying an output voltage of constant frequency and amplitude within the expected ranges of input during the operation. The matrix converter control using direct modulation method, modified Venturini modulation method and vector modulation method was simulated, the results were compared and it was inferred that vector modulation method was superior to the other two methods. With the proposed technique, voltage transfer ratio and harmonic profile have been improved compared to the other two modulation techniques. The behaviour of the system is corroborated by MATLAB Simulink, and hardware is realized using an FPGA controller. Experimental results are found to be matching with the simulation results.

The First Five Years of a Phase Theory for Complex Systems and Networks

In this paper,we review the development of a phase theory for systems and networks in its first five years,represented by a trilogy:Matrix phases and their properties;The MIMO LTI system phase response,its physical interpretations,the small phase theorem,and the sectored real lemma;The synchronization of a multi-agent network using phase alignment.Towards the end,we also summarize a list of ongoing research on the phase theory and speculate what will happen in the next five years.

Effects of metal binder on the microstructure and mechanical properties of Al2O3-based micro-nanocomposite ceramic tool material

The Al_2O_3-（W,Ti）C composites with Ni and Mo additions varying from 0vol% to 12vol% were prepared via hot pressing sintering under 30 MPa. The microstructure was investigated via X-ray diffraction（XRD） and scanning electron microscopy（SEM） equipped with energy dispersive spectrometry（EDS）. Mechanical properties such as flexural strength, fracture toughness, and Vickers hardness were also measured. Results show that the main phases A12O3 and（W,Ti）C were detected by XRD. Compound Mo Ni also existed in sintered nanocomposites. The fracture modes of the nanocomposites were both intergranular and transgranular fractures. The plastic deformation of metal particles and crack bridging were the main toughening mechanisms. The maximum flexural strength and fracture toughness were obtained for 9vol% and 12vol% additions of Ni and Mo, respectively. The hardness of the composites reduced gradually with increasing content of metals Ni and Mo.

Extraction of pipeline defect feature based on variational mode and optimal singular value decomposition

Because the magnetic signal information of pipeline defects obtained by magnetic flux leakage detection contains interference signals, it is difficult to accurately extract the features. Therefore, a novel pipeline defect feature extraction method based on VMD-OSVD (variational modal decomposition - optimal singular value decomposition) is proposed to promote the signal to noise ratio (SNR) and reduce aliasing in the frequency domain. By using the VMD method, the sampled magnetic signal is decomposed, and the optimal variational mode is selected according to the rate of relative change (VMK) of Shannon entropy (SE) to reconstruct the signal. After that, SVD algorithm is used to filter the reconstructed signal again, in which the H-matrix is optimized with the phase-space matrix to enhance SNR and decrease the frequency domain aliasing. The results show that the method has excellent denoising ability for defect magnetic signals, and SNR is increased by 21.01%, 24.04%, 0.96%, 32.14%, and 20.91%, respectively. The improved method has the best denoising effect on transverse mechanical scratches, but a poor denoising effect on spiral welding position. In the frequency domain, the characteristics of different defects are varied, and their corresponding frequency responses are spiral weld corrosion > transverse mechanical cracking > girth weld > deep hole > normal pipe. The high-frequency band is the spiral weld corrosion with f1 = 153.37 Hz. The low-frequency band is normal with f2 = 1 Hz. In general, the VMD-OSVD method is able to improve the SNR of the signal and characterize different pipe defects. And it has a certain guiding significance to the application of pipeline inspection in the field of safety in the future.

A General Approach for Direct Conversion of Single Phase AC to AC Converter for Induction Heating System

This paper signifies the study of modeling and simulation of a single phase matrix converter for induction heating system. The working principle and the control method, using PID are revealing in detail. The performance of the system is carried out in MATLAB/Simulink environment with pulse width modulation switching strategy by varying the duty cycle. PID control is employed to obtain the better performance for a specified input supply for various output frequencies. The proposed control strategy of AC to AC converter has been discussed with a wide range of operating frequencies and results in low Total Harmonic Distortion.

Heterogeneous particle structure formation during post-crystallization of spray-dried powder

The formation of heterogeneous particle structure in skim milk powder has been investigated in a post- crystallization facility using experimental and a mathematical model. Various processing conditions were used to produce these heterogeneous structures. The experimental process parameters were used as initial and boundary conditions for the model. The modelled data agreed well with the experimental data. The experimental and modelling results show that the powder processed at high water activity （aw = 0.7） with low initial moisture content （X0 = 0.01 kg/kg） developed a crystalline surface layer while the core of the particle remained amorphous. This structure is referred to as an egg-shell structure. The powder that was processed at low water activity （αw = 0.1） with high initial moisture content （X0 = 0.2 kg/kg） developed a crystalline core while the surface of the particle remained amorphous. This structure is referred to as an egg-yolk structure. Understanding the dependency of particle microstructures on the processing conditions could be useful when developing procedures to control the drying equipment because the particle microstructure affects the physicochemical properties of the powder and potential applications and behaviour of the powder.

SCATTERING PHASE MATRICES OF ICE CRYSTALS WITH HEXAGONAL PRISM AND TRIANGULAR PYRAMID FORM—A VECTOR RAY TRACING METHOD

The work presented previously by the authors(Cai and Liou,1982)has been extended in this paper. By making use of our improved model the calculations on scattering phase matrices of hexagonal prism ice crystals(HPIC)have been conducted for monodisperse and polydisperse systems.Compared with the model of Cai and Liou,the required computational quantity is decreased by about two orders of magni- tude and the errors of results are less for the new model.Meanwhile,the scattering phase matrices of triangular pyramid ice crystals(TPIC)are also computed in the paper,and the comparison between the scatterings of the two forms of ice crystals is performed.