International Journal of Nanomanufacturing (30 papers in press)
Directivity Process Modelling for the Figure Error Correction of Dual-Rotation Magnetorheological Finishing
by Yuyue Wang, Yun Zhang, Zhijing Feng
Abstract: To study Dual-Rotation Magnetorheological Finishing (DRMRF) technology and obtain a smoother surface, the model for the polishing process of the figure error correction (directivity process model) in DRMRF was established in this paper. Existing researches ignored the influence of feed rate and revolution upon removal function. In this paper, a method of modifying the removal function is presented, which takes the relative velocity of the Magnetorheological fluid (MR fluid) and the part into consideration. The directivity of removal amount during modelling adds a new dimension for analysis. The numerical simulation results of removal amount and its directivity show that the removal amount distributed more evenly along every direction because of the revolution of the wheel in DRMRF. The removal amount distribution is one of the fundamental differences between common MRF and DRMRF. Finally, a Fused Silica planar blank was polished by DRMRF, and the initial figure error was 10 nm RMS and 67 nm PV. The surface figure error is corrected to 2.4 nm RMS and 20 nm PV (full aperture = 95% diameter), and the stripe-like scratches are suppressed. The numerical simulation results and the experimental result indicates the effectiveness of DRMRF and the correctness of directivity process model.
Keywords: Magnetorheological Finishing; Dual-Rotation Magnetorheological Finishing; Figure error correction; Directivity modelling; Optical fabrication.
Effect of FAP characteristics on fixed abrasive polishing of CaF2 crystal
by Jun Li, Yongkai Tang, Longlong Song, Yongwei Zhu, Dunwen Zuo
Abstract: Pad is an important factor, which bears pressure to mechanically remove material in chemical mechanical polishing process. Owing to the abrasives fixed in pad, fixed abrasive pad (FAP) becomes more important and influences material removal and surface quality of wafer. The characteristics of FAP, abrasive type, particle size and matrix hardness, were analyzed and the effect on material removal rate (MRR) and surface quality was investigated in fixed abrasive polishing of CaF2 crystal. The results indicated that FAP with 3-5
Keywords: Fixed abrasive polishing; Fixed abrasive pad (FAP); CaF2 crystal; Matrix hardness; FAP characteristics.
Developed greener method based on MW implementation in manufacturing CNFs
by Loai Aljerf, Rim Nadra
Abstract: Many researchers have worked to develop certain applications of carbon nanofibers (CNFs) materials. However, they faced primer obstacles related to the improper optimised conditions that mostly give heterogeneous surfaces with low product quality. Therefore, this study comes as the first trial that uses Microwave (MW) technique in combination with assisted chemical vapour deposition (CVD) to provide higher heating rates which will generate homogeneous surfaces at short period thermal reaction. The MW absorption properties were stimulated based on a model for a single-layer plane wave absorber. The model used for manufacturing process was validated to give better selectivity which then was verified by ANOVA statistical analysis. After that, the morphology, characterisation, and purity of the product were tested. The outcomes of this study had confirmed that these materials are of highly-ordered pyrolitic graphite nature and successfully proved the significance of the optimised model at elevated temperatures. CNFs were obtained having uniform diameters (80-150nm) and long fibres (0.82-1.75
Keywords: Greener nanoproducts; cosmetics; industry; homogeneous dispersion; electron diffraction pattern; pyrolysis; multi-walled structures; turbostratic stacking; azimuthal broadening; polymeric bonding.
3D surface roughness evaluation of surface topography in ultrasonic vibration assisted end grinding of SiCp/Al composites
by Li Zhou, Ming Zhou, Xiong Han, Jin Zhou
Abstract: In order to investigate the effect of ultrasonic vibration and cutting conditions on surface quality accurately, the grinding experiments of SiCp/Al composites were carried out. And a comprehensive analysis to characterize the machined surface topography with 3D roughness such as amplitude parameters and spatial parameters was presented. The experimental results indicate that the machined surface of ultrasonic vibration assisted end grinding is filled with peaks and dales and the surface texture is almost isotropic. Ultrasonic vibration can tremendously improve the machined surface performance, comparing with conditional grinding. And low surface roughness value can be obtained in the conditions of high spindle speed, large vibration amplitude, low feed rate and small cutting depth.
Keywords: ultrasonic vibration assisted end grinding; SiCp/Al composites; surface quality; 3D surface roughness; grinding conditions.
Analytical modelling of a tri-axial flexible capacitive tactile sensing array
by Jian-Ping Yu, Xin Li, Yu-Liang Zhang
Abstract: In this paper, the analytical modelling of a tri-axial flexible capacitive tactile sensing array is proposed. A unit sensing element consists of a sensing electrode layer, an insulation layer, a common electrode layer and a surface layer. The sensing electrode layer is of flexible printed circuit board (FPCB) based structure, on which, four sensing electrodes and fragile interconnects for signal sampling are implemented. While the common electrode layer is patterned on polydimethlysiloxane (PDMS) based structures, on which only a common electrode is implemented. This design is on purpose of enhancing the device flexible rigidity. Four sensing electrodes and a common electrode constitute four capacitors in a unit sensing element, when the four capacitors are arranged in a square form, the measured contact force will be easily decomposed into its normal and shear components. The estimated sensitivities of a unit sensor are 0.43 and 0.17%/mN for the x-y and z-axes, respectively.
Keywords: capacitive microsensor; three-dimensional tactile sensing; common electrode; PDMS.
Study on eddy current loss characteristics of precision giant magnetostrictive actuator considering magnetic field distribution
by HuiFang Liu, Shuang Gao
Abstract: In order to accurately calculate eddy current loss of the rod-shaped giant magnetostrictivematerial ,improve the giant magnetostrictive actuator control accuracy of displacement , a eddy current loss model of rod GMM that considering the skin effect was established.Firstly, the traditional eddy current loss of rod-shaped GMM was deduced ,then discussed the influence of the skin effect for the inside magnetic field distribution of GMM rod ,finally analyzed the temperature characteristics of GMA throught the comsolmultiphysics finite element numerical analysis method .Compared with traditional eddy current loss ,under low frequency the two methods has same result, but under high frequency the new model can be more accurately calculate the eddy current loss of rod-shaped GMM .The research result has a great significance for improving the control precision and advancing the study of eddy current loss of GMA.
Keywords: giant magnetostrictive actuator ,eddy current loss; temperature characteristics.
Forces, form deviations and surface roughness in micro-milling of CoCr alloys for dental prostheses
by Frederik Elsner-Dörge, Oltmann Riemer, Melanie Willert, Axel Meier
Abstract: Micro-milling is commonly used for the manufacture of dental prostheses. Demands to the application of these prostheses require hard and tough materials like cobalt-chrome alloys. The cutting process is governed by static as well as dynamic interactions between the process and the structure of the workpiece. These interactions deteriorate the work result, especially the shape accuracy. The deflection of the milling tool is one effect, which has a significant influence. The work presented in this paper aims to establish a connection between forces, respectively tool deflection and resulting form deviations during micro-milling of defined geometries in CoCr alloys by measuring the active forces and evaluating the resulting form. In order to quantify the surface quality, white light interferometry is applied to measure the surface roughness Sa and Sq and the influence of feed rate vf and radial infeed ae on the surface roughness is derived.
Keywords: force measurement; form deviation; micro-milling; dental prostheses; cobalt chrome; shape accuracy; surface roughness.
Review on Extrusion of Magnesium Matrix Nano Composites
by D. Anburose, N. Manikanda Prabu, V.S. Thangarasu, G. Sureshkannan
Abstract: Increase in industrial requirements focusing on various research activities on composite material in a narrow region. This is being observed through replacement of material components over an existing one due to its betterment in structure behaviour and properties. In recent days, Nano technology comes to play an essential part in composites and coating of material to upgradation of parameters. This work constitute the outlines and importance of extrusion process in magnesium matrix Nano composites, meanwhile the effect of various factors like temperature, grain size, extrusion speed, extrusion ratio etc., on enhancing the microstructure and mechanical properties of the magnesium matrix composites. The extruded components have more excellent properties such as tensile strength, proof stress and elongation than the cast components. Addition of Nano particles may lead to significant inhibition in grain boundaries resulting in refined grains after extrusion resulting in high strength of the composites. Nano particles can significantly increase the mechanical strength of magnesium matrix by effectively promoting particle hardening mechanism than micro size particles.
Keywords: Magnesium matrix Nano composites; Nano particles; Extrusion process; dynamically re-crystallized grains.
An error separation method based on surface matching in large aspheric measurement
by Lin Sun, Shuming Yang, Pengfei Wu, Changsheng Li, Qijing Lin, Zhuangde Jiang
Abstract: Surface matching technique is the base of three-dimension surface error separation, which plays an important role in error compensation of ultra-precision manufacturing and automatic feedback control system. Surface error and surface roughness are key indicators for the evaluation of the quality of optical elements ultra-precision manufacturing. There are variations between the measured data and the actual surface data due to clamped positioning errors. Therefore, it is difficult to improve the manufacturing precision by error compensation based on evaluating the deviation between the measured data and the theoretical surface data directly. So we proposed an error separation technique based on surface matching, which can match the surface generated by fitting the measured data with the theoretical surface. And then we can obtain the spatial transformation parameters between measured surface and the actual surface using GA(Genetic Algorithm) for optimizing. Finally we can separate the spatial errors resulting from the clamped positioning errors of the measurement, and the actual measured surface errors are got.
Keywords: Surface matching; Error separation; Genetic Algorithm; Clamped positioning errors.
Influence of oxygen vacancies on the spontaneous polarization and piezoelectricity of ZnO: A first-principles study
by Haibo Niu
Abstract: By using the Berry phase methods, influence of oxygen vacancyrn(Vo) on the polarization property of ZnO has been investigated. Calculateed results indicate that the spontaneous polarization, the piezoelectric constants e31 and e33 are very sensitive to the concentration and distribution of Vo. The absolute values of them decrease nonlinearly as the Vo concentration increases. At the same concentration, non-uniform distribution of Vo is favored in energy, and can enhance the impact on spontaneous polarization and e31. 1.56% Vo-Vo complex can even reverse the orientation of spontaneous polarization, while the case for e33 is opposite, the influence is weakened. These findings suggest that the polarization property of ZnO might be adjusted by controlling the point defects.
Keywords: Oxygen Vacancy; Spontaneous Polarization; Piezoelectric Constants; Berry Phase; Maximally Localized Wannier functions; First Principles.
Research on temperature distribution mathematical model of cutting tool during heavy cutting difficult-to-machine materials
by Yaonan Cheng
Abstract: Heavy cutting is the main machining way for high-end equipment and the high temperature generated from the cutting process largely influences on the machining and tool life. Firstly, the main cutting area where energy was converted into cutting heat and the approximate rectangular distribution of cutting temperature were received through Finite Element Simulation of heavy cutting difficult-to-machine materials and the Finite Element Simulation provided fundamental basis for temperature distribution mathematical model. Then, heavy cutting characteristics and Jaeger moving heat source theory were combined to calculate the average temperature of shearing surface and rake face of the cutting tool. Finally, temperature distribution mathematical model in tool-chip contact area for heavy cutting difficult-to-machine materials was established using Kelren theory. The results show that the established mathematical model are consistent with experiment results and the model provides theoretical basis for quantitative analysis of heavy cutting temperature, the optimization of cutting parameters and heavy cutting tool design.
Keywords: cutting temperature; mathematical model; heavy cutting; difficult-to-machine materials.
Fractional-order composite control for the transient creep of a piezoelectric actuator
by Xueliang Zhao, Chengjin Zhang, Hongbo Liu
Abstract: In this study, a fractional-order composite controller is proposed to decrease the settling time and narrow the range of the transient creep of a piezoelectric actuator. The controller is composed of backlash modules and a fractional-order PI_λ controller. The backlash modules reduce the effect of the transient creep and the hysteresis, while the fractional-order controller decreases the settling time. Experiments show that the settling time is decreased from 11 ms to 6 ms. The controller exhibits good performance on step creep and hysteresis when the input signal is discretized into steps, whether 10, 20, 40 or 80 steps. All standard deviations are suppressed to levels 39.3% lower than that of a standard PI controller, and the range of the transient creep is reduced to 19.46%.
Keywords: piezoelectric actuator; dynamic creep; transient stage; fractional order; hysteresis.
The Material Design and Property Research of a Novel Machine Tool Material
by Bin Lin, Zehua Hu
Abstract: In this paper, a new machine tool material is put forward where PTFE resin is chosen as the matrix material for its properties of good acid and alkali corrosion resistance. High purity quartz and alumina ceramic microspherernare selected as the aggregates; nano-alumina and hollow glass microsphere are selected as the fillers. First, the aggregate gradation is analysed. Then, Young's modulus and sound attenuation coefficient are predicted in theory. Nonlinear regression analysis is conducted by Support Vector Machine (SVM). A 2D and 3D irregular polygon aggregate particles packing model is set up by MATLAB and the properties of the packing model are simulated by finite element analysis. Finally, several vibration experiments are conducted. The analysis results show that the chosen filler and aggregate can improve the stiffness and vibration characteristics of the material, which has a guiding significance to the machinery manufacturing industry.
Keywords: machine tool material; PTFE; high purity quartz; alumina ceramic microsphere; nano-alumina; hollow glass microsphere; Young's modulus; sound attenuation coefficient; nonlinear regression analysis; particle packing model; damping ratio.
Carbon nanotubes synthesis using Fe-Co-Mo/MgO tri-metallic catalyst: study the effect of reaction temperature, reaction time and catalyst weight
by Puguh Setyopratomo, Praswasti PDK Wulan, Mahmud Sudibandriyo
Abstract: MgO supported tri-metallic catalyst containing combination of transition metals Fe, Co, and Mo was used to synthesize carbon nanotubes (CNT) from liquefied petroleum gas by chemical vapor deposition (CVD) method. The effect of reaction temperature, reaction time and catalyst weight to the yield and the CNT properties was investigated. It found that the CNT yield increased with increasing the reaction temperature. Besides, increasing the reaction temperature lead to the increase of the diameter and wall thickness of the CNT. Moreover, it was found that the crystallinity of the synthesized CNT increase when the reaction temperature is raised. The yield is steadily increased with increasing reaction time and reach the highest yield at 21.95 g CNT/g catalyst which corresponds to reaction time 5 hours. The micro pores volume, BJH pores volume and total pores volume, all show a decrease when the reaction time is increased. The meso pores dominate the pore structure of the CNT product and contribute around 90 % of the total pores volume. Meanwhile, micro pores with pore size range around 0.3-0.4 nm dominate the micro pores and contribute approximately 50-60 % of the total micro pores volume. It also found that the CNT yield is decreased along with the increasing catalyst weight.
Keywords: carbon nanotubes; reaction time; reaction temperature; yield; liquefied petroleum gas; supported catalyst.
Fractal Description and Adsorption-Desorption Behavior of Coke Treated by Benzene pyrolysis carbons
by Zezhi Zhang
Abstract: For explaining why benzene pyrolysis carbons could inhibit coke deterioration in blast furnace, the adsorption-desorption data of coke sample treated by benzene pyrolysis carbons were obtained to establish adsorption-desorption isotherms and to fit fractal description model with Frenkel-Halsey-Hill equation. The SEM photographs of coke revealed that the pores of the infiltrated coke were almost filled with pyrolysis carbon particles. The fitted curves showed that the types of isotherms were similar to type II of IUPAC classification, and the hysteresis loops belonged to type H3 which represents a typical multilayer adsorption. Model tests indicated that the pore structure of the coke samples have obvious fractal feature and the fractal dimensions of coke sample treated by benzene pyrolysis carbons were smaller than that of original coke sample. So, it explained that benzene pyrolysis carbons can effectively inhibit coke deterioration by infiltrating into the pore structure of coke and reducing pore roughness.
Keywords: coke; inhibition deterioration; benzene pyrolysis carbons; adsorption-desorption; fractal description.
Precision of prestressed ball screw thermal behaviour in machine tool operating conditions
by Zbigniew Kowal, Jerzy Jedrzejewski, Taeweon Gim
Abstract: This paper presents an FEM model of a feed drive with a ball screw stiffness-wise, thermally and motion-wise integrated with the machine tool structure. The model takes into account the moving heat sources, the frictional and inertial interaction of the masses being shifted and the variable thermoelastic and stiffness interactions within the drive and the machine tool load-bearing structure. The results of heating up and displacement calculations for the ball screw, the bearing supports and the whole machine tool are analyzed with regard to positioning accuracy.
Keywords: machine tool; ball screw; model.
Study on engineering module design for liquid macromolecular ingredient content detection
by Xiaotong Na, Zhen Zhou, Chunyu Wang, Jia QI
Abstract: The liquid milk with the main ingredients of protein and fat was used as the research background for liquid macromolecular ingredient content detection in this paper. A model for the protein and fat ingredient content was established with the theory of scattered through ratio. Based on this, the photoelectric detection module was designed. Multiple photoelectric detection module circuit boards had been tested, the average error of the scattered light direction photoelectric detection circuit was 0.0072, and the average error of the photoelectric detection circuit in the direction of transmission light was 0.0094. The correlation coefficient of the established model can reach 0.97, and the system measurement uncertainty is about 0.078. The above test results show that the design meet the engineering application indicators basically. The detection module designed in this paper had the convenience, fast and efficient real-time performance, the reproducibility and stability was satisfactory.
Keywords: ingredient content detection; liquid macromolecular; engineering; module design; scattered through ratio.
INFLUENCE OF BORON NITRIDE NANO ADDITIVES IN CUTTING FLUID FOR IMPROVING SURFACE ROUGHNESS WITH MRR
by Manikanda Prabu Narayanasamy, Maniiarasan P, Nallusamy S, Jeevanantham S
Abstract: Surface quality of machined component is the essential requirement in industrial sectors by focusing on customer needs. Under this consideration, lot of researches brought in to proven results to enhance the surface quality in various machining Centre in different ways. Surface quality depends on the certain machining parameters which may have direct impact on output parameters such as surface roughness, MRR and indirectly correlated with the frictional resistance and heat transfer characteristics due to the relative motion of work and tool material. Previous results discussed the reduction state of frictional characteristics of machining in which selection of cutting fluids plays a vital role in reducing frictional resistance between tool and work. At present, quality and machining characteristics of cutting fluids attain better focus in such a way to improve the surface finish using additives and obviously Nano additives are assumed to be a possible solution to provide betterment of machining outcome. Present experimental work discusses the Preparation of Nano cutting fluids using boron nitride, Characteristics and influence on Machining parameters such as MRR, Tool life particularly surface quality in surface grinding operation. Result revealed that the addition of boron nitride Nano particles with base fluid is providing greater surface finish when compared to the conventional cutting fluids.
Keywords: Cutting Fluid; Grinding; Nano Additive; Surface Finish; MRR.
The behavior of nanofluids flooded in printed mini channels when excited by a small electrical potential
by Ahmad Yusairi Bani Hashim, Azri Nazran Afandi, Imran Syakir Mohamad, Syazwani Zainal Abidin, Amirah Abdullah
Abstract: This work sought to observe the response of a nanofluid put along in an electrical circuit while seeing the behavior of the fluid. Would the nanofluids have a characteristic of an electrolyte? Two mini channels were constructed using additive manufacturing approach. The nanofluids were flooded in the channels where they were connected in series with a generic resistor in a low voltage circuit. The fluids behaviors were observed through the recorded voltage drops at the resistor and also at the channels start and end points, respectively. The results showed minute currents were flowing in the circuit as the fluids recorded high resistances. Therefore, the nanofluids are naturally high resistance electrolytes. However, the real nature of the fluids exposed to electrical potentials for a longer duration is unknown.
Keywords: Mini channel; hydraulic diameter; carbon nanotube; carbon nanofiber; electrical conductivity; 3D printing; high resistance electrolyte.
Tailoring of Nanoparticles for Chemical Enhanced Oil Recovery Activities: A Review
by Augustine Agi, Radzuan Junin, Afeez Gbadamosi
Abstract: Nanotechnology has found its way to Petroleum Engineering, as it is a well-accepted path in the oil and gas industry to recover more oil trapped in the reservoir. The challenge in nanotechnology in the oil and gas industry is full-scale field application, due to cost. A considerable research and development investment is needed for the implementation of the technology in formulating cheap, readily available and environmentally friendly nanoparticles. In this review, methods of synthesizing the different types of nanoparticles is described, detailing the parameters involved in these techniques with the aim of tailoring their distinct properties such as; large surface area and ability to manipulate their behaviour for enhanced oil recovery. The difference between the natural and synthetic polymer nanoparticles and their various method of synthesis is discussed and their advantage in enhanced oil recovery is highlighted. The methods of synthesis can lower the interfacial adsorption of polymer with surface-active properties, prevent aggregation when the nanoparticle is subjected to flow, and prevent degradation. It can also form micelles and liposomes which can lower critical micelle concentration (CMC) and influence phase behaviour. The challenges encountered have opened new frontier for research and are also highlighted herein.
Keywords: Nanotechnology; Nanoparticle; Synthesis; Chemical Enhanced Oil Recovery; Polymer.
Tolerance Analysis of Slider-crank Mechanism for Assembly Functionality Check
by XUSONG XU
Abstract: Tolerance analysis is an effective way to improve the quality and decrease the cost of product. Functionality check is an important aspect of tolerance analysis. The purpose of functionality check is to analyse the stack-up of geometric deviation of part/feature whether it meets the demand of geometry and is it in the range of assembly tolerance. Geometric variations exist in the process of tolerance stack-up and transmission, on the other hand, the part itself has geometric error. In addition, since geometric deviation exists in the assembly feature between the parts, so the objects of tolerance analysis should contain part tolerance and assembly clearance. However, the usual tolerance analysis model does not include the assembly clearance. Aiming at this problem, we have done some research. Firstly, the nominal geometric transfer model and the stack-up model are established based on the Small Displacement Torsor(SDT) and Homogeneous Transformation Matrix(HTM). Secondly, HTM expression of the tolerance loop is constructed. Next, the assembly tolerance analysis matrix model is established and a new tolerance analysis method for assembling feasibility is put forward. The main advantages of the method are: 1) analysis object not only contains the tolerance, but also contains the assembly clearance; 2) it can analyse the stack-up deviation of the multiple assembly clearance; 3) it can effectively perform the assembly functionality check and the evaluation of the tolerance allocation results. At last, taking slider-crank mechanism as an example, the contrastive study of tolerance analysis for functionality check is done after establishing stack-up model of assembly tolerance analysis. The results show that it is prone to lead to misjudge when analysing only dimension tolerance, the analysis results of considering dimension tolerance, geometric tolerance and assembly clearance are more restrictively. However, it is more compliance with actual engineering.
Keywords: Tolerance analysis; Assembly tolerance; Tolerance stack-up model; Assembly clearance; Slider-crank Mechanism.
An Approach to Calculate Master Curve for Glass Molding Press Based on Finite Element Simulation
by Zhiguo Zhang, Yuxuan Sun
Abstract: A new approach is proposed to calculate the master curve (MC) of glass. It can solve the problem: when the temperature is higher than T_(t,l) (defined later), the measured shear relaxation modulus cant describe the mechanical response of the annealing stage during glass molding press(GMP) through the thermal rheological simple (TRS) theory. Based on the temperature dependent Yang's modulus and TRS theory, the MC with a reference temperature less than T_(t,l) is calculated by an iterative process.In order to verify the suitability of MC at high temperature, the MC and shear relaxation moduli are used in the finite element(FE) simulation at the isothermal compression stage. Similar von Mises stresses are shown and the usability of the MC at molding temperature is proved by the simulation results. In order to predict residual stress within the formed glass lens, the MC is used to conduct FE simulation for the whole GMP process.
Keywords: Glass molding press; Viscoelasticity; Thermal rheological simple; Master curve; Finite element.
Study on Novel Temperature Sensor based on Amorphous Carbon Film
by Qi Zhang, Xin Ma, Meiling Guo, Lei Yang, Yulong Zhao
Abstract: In this study, a new type of thermistor temperature sensor was developed. The sensing materials was amorphous carbon (a-C) film prepared using electron cyclotron resonance (ECR) plasma processing system under low energy electron irradiation sputtering. The nanostructure of a-C film was observed by transmission electron microscope (TEM), the atomic bonding and carbon hybridization condition was analyzed by Raman spectra and X-ray photoelectron spectroscopy (XPS) respectively. The linearity of temperature-resistance curve of this kind of a-C film was very good in certain temperature range, with high temperature coefficient of resistance (TCR). The a-C film by 50 eV electron irradiation can measure larger temperature range from -75 degree centigrade to 155 degree centigrade, with good repeatability. The working temperature range of a-C film by 100 eV electron irradiation was much smaller, but TCR absolute value of this film was higher. It can be concluded that the lower sp2 / sp3, the better linearity of temperature-resistance curve, the lower TCR absolute value in certain working temperature range. The research shows that this kind of a-C film temperature sensor has good linearity and repeatability, also it can be integrated with other MEMS sensor simply.
Keywords: Amorphous carbon film; Thermistor; Temperature sensor; Temperature resistance characterization; Temperature coefficient of resistance.
One Step Synthesis of ZnO Nanoparticles with Zinc Acetate Dehydrates and Potassium
by Md. Zaved Hossain Khan, Partha P. Das, Md. Abdullah
Abstract: In this study, pure ZnO nanoparticles have been synthesized by one step method where zinc acetate dehydrates and potassium use as a precursor. The UV-vis absorption spectrum was indicated that the reduction and stabilization of ZnO nanoparticles in aqueous medium. The peaks in X-ray diffraction pattern were revealed that the formation of ZnO in nanoscale and it good treaty with that of crystalline hexagonal structure. It was observed that ZnO elicited in form of nanoparticles and nanoflowers in spherical shape as well as homogeneous dispersion. The grain size were found to be 18-40nm. Thermo gravimetric analysis and Diffractive thermal analysis results were showed the thermal stability of ZnO nanoparticles in the temperature region of room temperature to 10000C. FTIR measurement was revealed that the synthesized Zn ion have potential interaction towards organic aqueous fluid to form of ZnO nanoparticles.
Keywords: ZnO nanoparticles; ZnO nanoflowers; crystalline structure; morphology; thermal analysis.
The Use Of Surface Plasmon Resonance Band Of Green Silver Nanoparticles and Conductometry For Quantitative Determination Of Minor Concentrations of Doxycycline hyclate And Oxytetracycline HCl in Pure and Pharmaceutical Dosage Forms.
by Rania A. Sayed, Manal S. El- Masry, Wafaa S. Hassan, Magda Y. El-Mammli, Abdalla Shalaby
Abstract: Two novel and sensitive methods for quantitative determination of doxycycline hyclate and oxytetracycline HCl were developed. The first method (Method A) is based on the reducing character of the cited drugs which causes chemical reduction of silver ions to silver nanoparticles (Ag-NPs) in the presence of polyvinyl pyrrolidone (PVP) as a stabilizing agent producing surface plasmon resonance which has absorption peaks at 424 and 428 nm for doxycycline hyclate and oxytetracycline HCl, respectively. The nanoparticles were characterized by UV-VIS spectrophotometry and transmission electron microscopy (TEM). The plasmon absorbance of the Ag-NPs was used for the quantitative spectrophotometric determination of the cited drugs. The second method (Method B) is a conductometric method which is based on the reaction of the cited drugs with phosphotungstic acid to form ion associates in aqueous system. Validation of the proposed methods was carried out.
Keywords: Silver nanoparticles; doxycycline hyclate; oxytetracycline HCl; conductometry and phosphotungstic acid.
Design and Simulation of MEMS Piezoelectric Vibration Energy Harvesters with Center Mass Block
by Lu Wang, Dejiang Lu, Shenrong Zhang, Zhikang Li, Yong Xia, Yunyun Luo, Libo Zhao, Zhuangde Jiang
Abstract: Abstract: MEMS-based piezoelectric vibration energy harvesters (MEMS-PVEHs) with center mass block are designed with the overall size 10102 mm3, two prototypes including piezoelectric unimorph and bimorph beams are used respectively. The MEMS-PVEHs have a lower resonant frequency (109.20Hz for unimorph beam and 84.80Hz for bimorph beam), and high optimal mechanical and piezoelectric power density (22.30mW/(g2cm3) for unimorph and 29.02mW/(g2cm3) for bimorph beam). This paper studies the characteristics of MEMS-PVEHs by modeling and simulation in COMSOL. Their eigenfrequencies are analyzed firstly, their optimal piezoelectric outputs are explored by changing excitation frequency and load resistance secondly, then the piezoelectric unimorph & bimorph beams are compared finally. The simulation results show that the optimal excitation frequency is slightly higher than the eigenfrequency, and the maximum piezoelectric power of the PVEH can be obtained only when the appropriate excitation frequency and load resistance are selected, and the power generation efficiency is 0.5. By comparing the unimorph and bimorph beams, it is suggested that the unimorph and bimorph MEMS-PVEHs should be designed to improve the piezoelectric output by decreasing resonant frequency and increasing input mechanical power. Finally, the piezoelectric unimorph with double opposite electrodes is designed based on the MEMS fabrication process.
Keywords: Energy harvesting; Piezoelectric; MEMS; Resonant frequency; Power optimization.
Preparation and characterization of nanokaolinite photocatalyst for removal of P-nitrophenol under UV irradiation
by Said El-Sheikh
Abstract: A nanokaolinite photocatalyst was prepared successfully using intercalating method which depends on insertion of chemical reagent between bulk kaolinite layers followed by delamination process. The as-prepared nanokaolinite photocatalysts were characterized by X-ray diffraction, FTIR analysis, Transmission electron microscope (TEM) and UV-vis diffuse reflectance spectroscopy. XRD data show that the crystals size of exfoliated nanokaolinite in the range ~ 26-32 nm. FTIR peaks assign to presence of nitrogen between nanokaolinite layers, which maybe lead to decrease the band gap of prepared samples. The photocatalytic activity of nanokaolinite photocatalysts was investigated by degradation of PNP under ultra-violet irradiation. The ideal nanokaolinite sample (K/urea) show extraordinary photocatalytic activity (100%) toward PNP within 30 min. due to its enhanced band gap value.
Keywords: Delamination; Kaolinite; phyllosilicates family; Intercalation; Photodegradation; P-nitrophenol; Paper filler; Photocatalytic activity.
Research on processing technology of grinding aspheric workpiece in the five-axis machine tool
by Jianfeng Liu
Abstract: Aspheric optical components have been widely used recently because of their unique advantages. Thus, it is necessary to investigate processing technology of such aspheric parts. In this paper, an aspherical mirror is ground with cup wheel in five-axis CNC (Computer Numerical Control) machine tool and corresponding processes were investigated. To improve machining efficiency and reduce tool wear, the workpiece is firstly ground to be a spherical mirror, and then it is ground to be the aspheric contour. The best fitting spherical mathematical equation is derived by the axisymmetric quadratic aspheric generatrix equation. A aspheric mirror was ground with cup wheel with five-axis CNC (Computer Numerical Control) machine tool. The aspheric curve is processed into a paraboloid shape. The experimental results show that the surface profile of the aspherical lens is consistent with the designed profile, and the PV (Peak Value) value of the error is . Such results can be accepted in consideration of working allowance for polishing. According to the experimental results, the cause of the error was analyzed and methods for improving precision were proposed.
Keywords: five-axis machine tool; cup wheel; aspheric surface; fitting spherical radius.
Study on the influence of spindle vibration on the surface roughness of ultra-precision fly cutting
by Jianpu Xi, Bin Li, Dongxu Ren, Zexiang Zhao, Huiying Zhao
Abstract: Spindle vibration is a key factor influencing the quality of the processed surfaces during ultra-precision fly cutting. An extremely tiny vibration will directly influence the quality of the surface at the nanoscale. Therefore, in this study, a mathematical model of aerostatic spindle vibration under pulsed excitation was established by analyzing the characteristic cutting path of a fly cutter head and the state of the spindle under interrupted cutting force, and then, the axial and radial of the aerostatic spindle to pulses during periodically interrupted fly cutting were calculated using a Fourier series. Under the periodic processing mode of high-speed fly cutting, a simulation and experimental analysis on the spindle vibration were conducted. The experimental results show that the cutting force and spindle speed are major factors influencing surface roughness. According to the simulation and experimental analysis, reliable theoretical guidance is provided for the improvement and prediction of surface quality of an ultra-precision fly cutting.
Keywords: aerostatic spindle; fly cutting; dynamic response; vibration; surface roughness
Coaxiality Detection Method with Non-adjustment for Installation Errors
by Xin Jin, Qiushuang Zhang, Ke Shang, Yimin Pu, Zhijing Zhang, Huan Guo
Abstract: During the assembly of the engine casing, the coaxiality detection for the two assemblies are essential. And the modern manufacturing industry has put forward higher requirements for the coaxiality measurement with the development of the industrial technology. The existing coaxiality detection methods are mostly based on manual measurements. It takes long time to adjust the axes of assembly parts and turntable to coincide by the current measurement method, which greatly affects production efficiency. To solve the problem, this paper proposes a coaxiality detection method which can compensate assembly installation errors automatically. The coaxiality measurement method based on the position of the assembly is deduced by introducing the measurement mechanism of the coordinate measuring machine. The data processing uses coordinate transformation and least squares fitting method. Experimental verification shows that the method do not need to adjust the assembly part repeatedly, so measuring time is reduced greatly. The method simplifies the measurement steps, and provide supports of methods and techniques for automatic detect.
Keywords: Installation errors; Coaxiality; Non-adjustment; Automation; Detection method