Most statistical contact analyses assume that surface heights and peak (summit) height distributions follow a Gaussian distribution. However, engineering surfaces are frequently non-Gaussian with a degree of non-Gaussian character dependent upon materials and surface finishing processes used. For example, magnetic rigid disk surfaces used in magnetic storage industry are highly non Gaussian. The use of a Gaussian analysis in such cases can lead to erroneous results. This study for the first time presents a method to carry out a statistical analysis of non-Gaussian surfaces. Real area of contact, number of contacts, contact pressure and meniscus force (in wet interfaces) are calculated for probability density functions having different skewness and kurtosis. From these curves, the optimum value of skewness and kurtosis can be predicted for minimum static/kinetic friction. It is found that a range of positive skewness (between 0.3–0.7) and a high kurtosis (greater than five) significantly lower the real area of contact and meniscus contribution implying low friction and wear. Also, sensitivity of film thickness to static friction goes down for a surface with a positive skewness and a high kurtosis. 相似文献
Serratiopeptidase is a proteolytic enzyme obtained from serratia marcescens strain E-15 and used as anti-inflammatory and analgesic drug. Serratiopeptidase undergoes first pass metabolism, causes the gastrointestinal disturbance and systemic toxicity after oral administration. To overcome the limitations of serratiopeptidase, transdermal drug delivery system is an alternative method. So, the aim of present work was to modulate serratiopeptidase transdermal patch by lipid-based transfersomes. Particle size of drug was the major concern to cross stratum corneum which acts as a barrier. This difficulty was surmounted by modulating the vesicles such as transfersomes which carries the drug into the skin by passing the barrier of stratum corneum. Serratiopeptidase was encapsulated in transfersomes in different ratios of lecithin and cholesterol. Particle size of transfersomes, folding endurance, thickness, tensile strength, adhesion test, encapsulation efficiency, in vitro and in vivo release, Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimeter (DSC) studies of patch were used as characterization parameters. Serratiopeptidase transfersomes size was found to be 50 µm with smooth surface. The promising entrapment efficiencies of transfersomes and formulation were found to be 96.76 and 98.7%, respectively. In vitro and in vivo release studies showed controlled and steady release of serratiopeptidase for 24 h. FTIR and DSC confirmed the encapsulation of drug in patch without interaction. It is concluded that transfersomes are interesting carriers for enzymatic drugs for topical application. 相似文献
The present study was carried out to evaluate antioxidant potential of ashwagandha, clove, coriander, green tea, shatavari and vidarikand extracts as compared to BHA. Clove, coriander and green tea extracts showed significantly higher antioxidant activity than vidarikand, shatavari and ashwagandha extracts. Radical‐scavenging activity by DPPH model system revealed that clove and green tea extracts were superior to other extracts. All the natural antioxidants significantly reduced the formation of peroxides, FFA, thiobarbituric acid value and conjugated dienes. Ghee with added clove, green tea and coriander extracts showed higher induction period as compared to ghee containing vidarikand, ashwagandha, shatavari or BHA. 相似文献
This paper outlines an abstraction process in which a particular class of hybrid automata with continuous dynamics that have
parameterized positive limit sets, are being abstracted into finite transition systems. The limit sets with their corresponding
attraction regions define pre- and post-conditions for the continuous dynamics, and determine the transitions in the discrete
abstraction. An observable (weak) bisimulation equivalence is established between the two models. The abstraction process
described can find application in verification, as well as in planning and symbolic control. 相似文献
The International Journal of Advanced Manufacturing Technology - The advanced high-strength steels (AHSS) have become an interesting alternative to the automotive industry to reduce vehicle weight... 相似文献
Semiconductors with the group of IV-VI are key components of future photonics technology due to their unique properties. In the present study, we investigated the influence of nickel inclusion on the structural and electrical responsiveness of SnSe-layered crystals produced through direct vapour transport. The elemental composition, stoichiometry of grown crystals and the orthorhombic structure were investigated by EDAX and XRD analysis. The phase and high crystallinity of produced compounds are revealed by scanning electron microscopy and the SAED pattern of transmission electron microscopy. Nickel-doped SnSe photodetector exhibited a photocurrent of 53.83 nA, which is six times higher compared to the pristine SnSe. Moreover, the pristine and nickel-doped SnSe demonstrated excellent photoresponse behaviour under visible light. Additionally, important photodetection characteristics such as photoresponsivity (R), spectral detectivity (D), rise time and decay time are assessed. Our findings contribute to a better understanding of SnSe and Ni-doped SnSe-based photodetection capabilities which open up the future gateway for SnSe-based optoelectronic devices.
Synthetic self-healing materials are a new prototype in polymeric coatings. In the present investigation, soybean oil along with drier was encapsulated in urea–formaldehyde (UF) microcapsules, which were successfully prepared by in situ polymerization and their self-healing ability, the corrosion resistance, gloss, and adhesion strength of microcapsules were studied. The synthesized microcapsules were characterized by Fourier transform infrared spectrometer for identification of separated core and shell materials and their surface morphology was studied by scanning electron microscope. The particle size was checked under optical microscope and confirmed with particle size analyzer. Effectiveness of soybean oil-filled microcapsules was investigated for healing of cracks generated in anticorrosive coatings. Cracks in paint coatings were found to be healed when soybean oil was released from microcapsules under simulated mechanical action and the corrosion resistance of healed area was evaluated by immersion study. 相似文献
Microencapsulation of anthocyanin pigment present in Garcinia indica Choisy was carried out with maltodextrin of various dextrose equivalents (DE 06, 19, 21, and 33) and other additives such as gum acacia and tricalcium phosphate to enhance the stability of the pigment. The microencapsulated pigment containing 5.0% maltodextrin DE 21, 0.25% gum acacia, and 0.25% tricalcium phosphate was found to have lowest hygroscopic moisture content (4.38%), highest antioxidant activity (69.90%), and highest anthocyanin content (485 mg/100 g). The glass transition temperature was 44.59°C. The sorption isotherms for microencapsulated powder showed that the samples were stable up to water activity less than 0.43. The scanning electron microscope structures depicted that the particle size ranged from 5 to 50 μm with smooth spheres. Storage at 4°C increased the half-life twofold compared to that of the spray-dried product kept at ambient temperature (25°C). 相似文献
Engineering with Computers - The bending deflections and the corresponding optimal fiber angle sequences of the subsequent layers have been predicted in this article using a hybrid technique. The... 相似文献