International Journal of Nanomanufacturing (12 papers in press)
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 S.M. El-Sheikh, Ahmed Shawky, Sabrin M. Abdo, Mohamed Nageeb Rashed, Thanaa I. El-Dosoqy
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.
Submicron Centroid Position Measurement Method of Screw Connected Structure under Temperature Load
by Xiao Chen, Muzheng Xiao, Zifu Wang, Zhijing Zhang, Xin Jin
Abstract: In this paper, a symmetrical fixed structure was designed, and two laser displacement sensors were placed in the two ends of screw connection structure for a real-time measurement. The entire measuring device was placed in a temperature controllable environment to measure the position change of the screw connection structure while temperature load is applied. The centroid position change of screw connection structure was calculated from the measured data. Uncertainty of the measurement method was analyzed which is about 0.1μm. And a measurement experiment was carried out on the design structural. Under the action of a pre-tightening force of 400N and a temperature change of 40℃, the maximum centroid position change of the structure was about 7.4μm. Finally, simulation of the measured structure was carried out to confirmed that the measurement method proposed in this paper is effective.
Keywords: submicron; measurement method; screw connected structures; temperature load; screw pre-tightening force.
Novel green synthesis of silver nanoparticles from newly discovered Putranjivaceae plant leaf extract and their antibacterial studies
by Shareefraza J. Ukkund, Momin Ashraf, Abhinaya Nellerichale, Apoorva B. Udupa, Sapna Kannan, Vinaya B. Koradoor, P. Prasad, Krishanraja Acharya
Abstract: Silver nanoparticles (AgNPs) have been synthesised by many plant extracts so far. In this novel study we have synthesised AgNPs from Putranjivaceae leaf extract. The new plant Putranjivaceae was discovered in 2017 (Krishna et al., 2017) in West Bengal, India. The AgNO3 is treated with the leaf extract and subjected to microwave irradiation to get AgNPs. The nanoparticles were synthesised in just 10 minutes and subjected to characterisation for structural and morphological studies. The synthesis was rapid and shape of nanoparticles found uniform in nature by SEM and TEM analysis observed to of 2025nm. The primary confirmation of AgNPs was done by UV-visible-spectrophotometer and EDAX. The synthesised silver nanoparticles were optimised by several parameters like pH, salinity and substrate concentration to observe the maximum production. The silver nanoparticles were then conjugated with several antibiotics for antibacterial studies out of which erythromycin showed 3 fold increments in its efficiency.
Keywords: Drypetes species; Putranjivaceae leaf extracts; silver nanoparticles; antibacterial studies; UV-visible spectrophotometer.
Study of Silver Nanoparticles activity against He-La Cell Lines
by Shweta Rajawat, M.M. Malik
Abstract: In the present work, poly-dispersed silver nanoparticles (Ag NPs), using principles of green chemistry, are synthesized and their anti-cancer activity against He-La cell lines is studied. The synthesis method is easy, simple, environment friendly and does not require any sophisticated labs. One of the physical synthesis method, electrolytic deposition technique with black tea leaf extract as capping agent, was designed to synthesize silver nanoparticles. Elemental analysis using X-ray patterns show synthesis of highly pure silver nanoparticles. Activity against cell lines was observed in a dose-dependent manner using MTT assay. The IC50 value of sample against He-La cervical cancer cell lines were obtained at 30-fold dilutions of concentration of 178
Keywords: Green Technology; Silver Nanoparticles; He-La cervical cell lines; IC50 values.
Measurement and Compensation Method of Gantry CNC Machine Tool Based on Single Laser Synchronization Method
by Jia Minqiang, Gao Ran, Sun Lei, Guan Qianqian
Abstract: The gantry CNC machine tool has unique structure and characteristic. The gantry machine tool does not always form a symmetrical structure and symmetrical force during the machining process, as well as various uncertainties in the course of operation. The inconsistency will cause a non-synchronized error in the biaxial synchronous system. The no-synchronized error will affect the machining accuracy, cause the beam to be pulled and the gantry frame or drive element to be damaged. Therefore the biaxial synchronization error of the CNC machine tool is one of its most important specifications, and it should be solved firstly when compensating. This paper presents a new method called single laser synchronization method, which bases on the structure and operation characteristics of the gantry CNC machine tool, and puts forward the measurement method and compensation method of positioning error. This new method includes a special optical path layout, a characteristic way of measurement and compensation. This method has some advantages such as high precision, low-cost, efficiency etc.
Keywords: Gantry CNC Machine Tool; Measurement; Compensation; Laser.
Study on grinding damage of high chromium alloy based on molecular dynamics
by Xiaoguang Guo, Xiaoli Wang, Song Yuan, Yang Li, Renke Kang, Zhuji Jin
Abstract: The new cast high chromium alloy is the conventional material of the nuclear main pump thrust-bearing with good wear and corrosion resistance. According to the structural characteristics of high chromium alloy, the simulation model and the coupling potential function were constructed to study the grinding damage layer using molecular dynamics method. The simulation results show that the crystal lattice distortion caused by carbon atoms in the formation of interstitial solid solution leads to the occurrence of amorphous structure after full relaxation. The break and recombination of metal bond and nonmetal bond between atoms in the alloy result in the occurrence of damaged layer under grinding. And the bond angles between the atoms in the damage layer are less than that in the alloy matrix. The damage layer is mainly composed of atoms in front of the abrasive particle and the atoms of extrusion deformation in the bottom. Moreover, with the increase of grinding depth, the cutting force and the damage layer thickness increase. The study is conducive to understand the damage formation mechanism of high-chromium alloy materials in micro-nano processing, and provides a theoretical reference value for the actual processing.
Keywords: Molecular dynamics; High chromium alloy; Nanoscratch; The coupling potential function; The damage layer.
Control of Crystal morphology in Energetic Drop-on-demand Inkjet Method
by Ruirui Zhang, Qi Lehua
Abstract: Nano-energetic materials are attracted the worldwide attention since they play an important role in fabricating insensitive high-energy explosives, micro-energetic devices, and explosive detectors. Here, we report a simple, but an eﬀective strategy to control droplet coalescence during inkjet printing, as a major variable, to tailor the nanoscale morphology of energetic materials produced upon evaporation of all-liquid inks. We expect to achieve energetic materials with nanoscale particles by integrating the deposition and the nanocrystallization of energetic droplets in one step. A proprietary uniform energetic micro-droplet printing equipment is utilized to reveal the influence of temperature, frequency on the particle size of energetic materials. Uniform line, with the particle size between nanometer and microns, is successfully obtained, showing the feasibility of the proposed method for preparing the microscale charge of nano-energetic materials. We also discussed the effect of droplet coalescence on the crystal morphology.
Keywords: uniform droplet injecti；printing parameters; insensitive high-energy explosives ;nanometer explosive; inkjet printing; energetic material; micro-energetic devices; microscale charge; control the particle size; crystal morphology; supersaturation; crystal nucleation and growth; grain refinement.