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91.
Development of a novel flexure-based microgripper for high precision micro-object manipulation 总被引:2,自引:0,他引:2
Micro-scaled parts with dimension below 1 mm need to be manipulated with high precision and consistency in order to guarantee successful microassembly process. Often these requirements are difficult to be achieved particularly due to the problems associated with the structural integrity of the grasping mechanism which will affect the accuracy of the manipulation. Furthermore, the object's texture and fragility imply that small perturbation by the grasping mechanism can result in substantial damage to the object and leads to the degradation of its geometry, shape, and quality. This paper focuses on the unification of two designing approaches to develop a compliant-based microgripper for performing high precision manipulation of micro-objects. A combination of Pseudo Rigid Body Model (PRBM) and Finite Element Analysis (FEA) technique has proven to improve the design efficiency by providing the essential guideline to expedite the prototyping procedure which effectively reduces the cost and modeling time. An Electro Discharge Machining (EDM) technique was utilized for the fabrication of the device. Series of experimental studies were conducted for performance verification and the results are compared with the computational analysis results. A high displacement amplification and maximum stroke of 100 μm can be achieved. 相似文献
92.
Pooria Varahram Somayeh Mohammady Borhanuddin Mohd Ali 《Wireless Personal Communications》2013,72(2):1125-1137
Peak-to-average power ratio (PAPR) is one of the main drawbacks in orthogonal frequency division multiplexing (OFDM) systems. High PAPR forces the power amplifier to back off in order to operate in its linear region, which degrades the power efficiency of the system. Several PAPR reduction techniques have been developed, but most of them have not considered both complexity and PAPR reduction. In this paper, a novel PAPR reduction scheme based on the insertion of dummy sequences to an enhanced partial transmit sequence is proposed. By applying this scheme the PAPR performance is enhanced compared to the conventional methods while the complexity is significantly reduced. Numerical analysis is carried out with OFDM signal and QPSK modulation. 相似文献
93.
Syazwan Afif Mohd Zobir Zulkarnain Zainal Mohd Zobir Hussein 《Materials Chemistry and Physics》2010,124(1):477-481
The effect of the addition of very small amount of polyvinyl alcohol (PVA) on the resulting physicochemical properties of ZnO synthesized by ethylene glycol-hydrothermal method was studied. Significant change in particle size distribution and specific surface area can be observed even only 0.02% PVA (w/w) was added into the ethylene glycol (EG) solution, in which the median particle size distribution increased from 5 to 8 nm and at the same time the specific surface area is also increased to nearly 50%. Further addition of PVA resulted in the decrease of the specific surface area due to the formation of agglomeration and aggregation of particles as observed by FESEM study. This study shows that the presence of minute amount of polymer, PVA plays very crucial role in determining the resulting properties of the synthesized ZnO by EG-hydrothermal method. 相似文献
94.
DOE applied to multi-response optimisation study on performance,combustion and emission characteristics of a VCR diesel engine 总被引:1,自引:0,他引:1
Syed Azam Pasha Quadri M. Masood Tabish Wahidi Mohd Ghouse Sundkey Mohd Wajid 《国际自然能源杂志》2017,38(8):759-764
There are various parameters which may influence the IC engine performance. The trial and error method is a technique used to identify the best parameters. However, this method demands extensive experimental work and results in a great waste of time and resources. Thus, the design of experiments (DOEs) developed by Taguchi is employed. The multi-responses which need to be maximised are brake thermal efficiency, mechanical efficiency, cylinder pressure and cumulative heat release rate, whereas the responses which are to be minimised are specific fuel consumption, oxides of nitrogen and carbon monoxide. In the present study, an optimised DOE(L9) orthogonal array based on the Taguchi statistical method was formulated and a series of experiments were conducted under controlled supervision by considering three different injection operating pressures (IOPs) (200, 220 and 240 bar) and three different compression ratios (CRs) (16.5, 17.5 and 18.5). The main objective of this paper is to find the best suited IOP and CR values which obtain higher performance, better combustion and lower emissions. 相似文献
95.
Mikael Wahlström Miika Aittala Helinä Kotilainen Tiina Yli-Karhu Janne Porkka Esa Nykänen 《Virtual Reality》2010,14(3):197-211
Several studies indicate that virtual reality (VR) systems are useful for end-user participation in an environmental design
process. However, these systems can be costly and thus support for the decision whether to invest in a VR of some type is
useful. This study presents a novel method for analysing the usefulness of a VR system for the purpose of end-user participation.
We collected qualitative end-user opinion data in the real environment and then contrasted this data with the capabilities
of a VR system. Additionally, to better understand the capabilities of the VR used, we examined how the end-users perceive
the used virtual environment, which in this case was CAVE, an immersive VR system where projectors are directed to the walls
of a room-sized cube. In this way, we analysed whether the same functions and elements identified by end-users on the actual
wards could also be evaluated in the CAVE. Eleven nurses and 11 patients participated in the study by evaluating a bathroom
and/or four patient rooms modelled by the CAVE and the actual hospital wards. The CAVE was convenient for evaluating most
issues identified by the study participants in the actual hospital wards, i.e. aesthetics; correct location of equipment,
supplies and materials; distraction by or the good companion of other patients as well as window position and size and living/workspace.
However, it was not possible to evaluate with full certainty the possibilities for bracing against grab bars or other objects
in the VR, and this was found to be relevant to the independent functioning of patients with limited mobility. Also, due to
the relatively low luminance levels of projectors, evaluations regarding lighting were considered unreliable. Moreover, end-users
were not always certain about the sizes and sufficiency of space in the CAVE. Solutions to overcome these limitations were
proposed. 相似文献
96.
Masoud Zabeti Wan Mohd Ashri Wan Daud Mohamed Kheireddine Aroua 《Applied Catalysis A: General》2009,366(1):154-159
In this work the response surface methodology (RSM) in conjunction with the central composite design (CCD) were used to optimize the activity of CaO/Al2O3 solid catalysts for the production of biodiesel. In order to measure the catalyst activity, we used palm oil as a representative raw material for the conversion to biodiesel. The biodiesel production was carried out in a batch laboratory scale reactor. The results showed that both the calcination temperature and the amount of calcium oxide loaded on the support had significant positive effects on the biodiesel yield. The maximum basicity and biodiesel yield obtained were about 194 μmol/g and 94%, respectively. Overall, the catalyst showed high performance at moderate operating conditions and its activity was maintained after two cycles. 相似文献
97.
Hawbani Ammar Wang Xingfu Kuhlani Hassan Karmoshi Saleem Ghoul Rafia Sharabi Yaser Torbosh Esa 《Wireless Networks》2018,24(7):2723-2734
Wireless Networks - Data dissemination toward static sinks causes the nearby nodes to deplete their energy quicker than the other nodes in the field (i.e., this is referred to as the hotspot... 相似文献
98.
Elyas Sadeq Alaghbari Zulkarnain Zainal Imad Hamadneh Mohd Zobir Bin Hussein Mohd Haniff Bin Wahid 《Journal of Superconductivity and Novel Magnetism》2012,25(2):255-260
Zn- and Ca-doped ErBa2Cu3O7−δ
were successfully prepared via coprecipitation method using metal acetates as the starting salts. The precipitated samples
were calcined for 20 h at 900 °C and sintered at 920 °C for 24 h. All heat treatments were carried out under oxygen environment.
Results show that there is a selectivity of the doping site depending on the ionic radius of the dopant. Furthermore, increase
in the critical temperature, T
c
, was observed in 0.05 mole of calcium and zinc doped samples. The difference in ionic radius of the dopant led to the increase
in porosity as the ionic radius decreases. On the other hand, structural distortion increased as the difference of ionic radius
became larger. 相似文献
99.
Conductive fibers based on polyaniline (PANI) and polyacrylonitrile (PAN) were obtained by stirring with magnetic bar. This research was conducted to investigate conducting fibers of polyaniline:polyacrylonitrile (PANI:PAN) composite with different weight ratios of aniline in PAN matrix. The fibers were prepared by stirring process. The best conductivity behavior of the fibers was obtained with 5 mL of aniline. The fibers obtained were characterized using Fourier-transform infrared spectra (FTIR), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The variation of electrical conductivity with different type doping agents (HCl, H2SO4 and HClO4) and the stability in terms of DC electrical conductivity retention was studied in an oxidative environment by isothermal characteristics. 相似文献
100.
Hammed Ademola Monsur Hamzah Mohd Salleh Hassan A. Alkahtani 《International Journal of Food Properties》2013,16(6):1224-1236
Fish gelatins obtained from perch fish skin pretreated with various solutions containing acetic acid, sodium hydroxide (NaOH) and sodium chloride (NaCl) were successfully characterized for their nanostructure pattern using field emission scanning electron microscopy. Each pretreatment transformed collagen to gelatin with fibril, zigzag cracks, straight rods, and cross-linked rods nanostructure patterns. Pretreatment solutions also affect the gel yield, gel strength, amino acid profile, and functional groups in perch gelatin as analyzed by Fourier transform infrared spectroscopy. Samples pretreated with NaCl, NaOH, and acetic acid solution showed the highest gel yield (22.84%) and gel strength (179.84 g). Fourier transform infrared spectra for perch gelatins also revealed weak C–N amide II and III bond stretches as well as weak C=O bond stretch. 相似文献