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61.
Anirban Sen Gupta 《Polymer》2005,46(7):2133-2140
Since their introduction by Kohn and Langer et al. in 1984, l-tyrosine based ‘pseudo’ poly(amino acids) have undergone extensive research in the area of polymeric biomaterials. Starting from l-tyrosine based diphenolic monomers, polyiminocarbonates, polycarbonates and polyarylates have been developed by Kohn and co-workers and are being investigated for potential orthopedic biomaterial applications. Mao et al. have reported development of l-tyrosine based polyphosphates and polyphosphonates in a patent, however, detailed structural and physico-chemical characterization studies on such polymers have not been reported yet. For the purpose of the current paper, using a novel solid phase process for synthesis of l-tyrosine based diphenolic monomers and adapting the polymerization process described by Mao et al., l-tyrosine based polyphosphates were developed and investigated for their pertinent bioengineering properties. The properties investigated consist of chemical solubility, hydrophilicity and hydrolytic degradation. The results of this investigation are crucial to validate further investigation of biomaterial applications of these polymers. 相似文献
62.
System identification of limb mechanics can help diagnose ailments and can aid in the optimization of robotic limb control parameters and designs. An interesting fluid phenomenon--the Coanda? effect--is utilized in a portable actuator to provide a stochastic binary force disturbance to a limb system. The design of the actuator is approached with the goal of creating a portable device which could be deployed on human or robotic limbs for in situ mechanical system identification. The viability of the device is demonstrated by identifying the parameters of an underdamped elastic beam system with fixed inertia and stiffness and variable damping. The nonparametric compliance impulse response yielded from the system identification is modeled as a second-order system and the resultant parameters are found to be in excellent agreement with those found using more traditional system identification techniques. The current design could be further miniaturized and developed as a portable, wireless, unrestrained mechanical system identification instrument for less intrusive and more widespread use. 相似文献
63.
M. S. Inpasalini Lalit Kumar Sharma Anirban Roychowdhury Dipankar Das Samrat Mukherjee 《Journal of Materials Science: Materials in Electronics》2017,28(4):3285-3292
This article reports the structural, optical and magnetic properties of transition metal (Ni, Co, Mn and Fe) doped SnO2 nanoparticles prepared by modified Pechini sol–gel method. From the X-ray diffraction studies, it is obvious that all the synthesized samples show a phase purity of rutile tetragonal crystal structure of SnO2. The morphology was studied and the particle sizes were estimated from the field emission scanning electron microscopy. From photoluminescence spectra, we observed emission due to the presence of singly ionized oxygen vacancies. Raman spectroscopy shows dominant peaks at 644 and 782 cm?1 which were ascribed to A1g and B2g modes of the rutile structure. Isomer shifting due to dopant addition and large quadrupole splitting due to surface defects were observed in Mössbauer spectra. All the samples show ferromagnetic ordering up to 1 T. The relatively stronger ferromagnetic nature in Fe and Co doped SnO2 is due to the strong p–d exchange interaction. In case of Ni and Mn doped SnO2 samples, the lack of carrier-mediated interaction due to its inherent semiconducting nature reduces the total magnetic moment observed in these samples. The exchange coupling depends on the dopant type and its concentration. 相似文献
64.
Multimedia Tools and Applications - In the age of digital world, the wide dissemination of images need bandwidth (BW) efficient transmission as well as ownership protection during transmission over... 相似文献
65.
66.
Anirban Chowdhury Samantha O'Callaghan Thomas A. Skidmore Craig James Steven J. Milne 《Journal of the American Ceramic Society》2009,92(3):758-761
A Pechini-based chemical synthesis route was used to produce powders of Na0.5 K0.5 NbO3 (NKN). The thermochemistry of the gel was investigated using thermogravimetric analysis-fourier transform infrared (TGA-FTIR) evolved gas analysis; in addition, powder FTIR was used to analyze the gel residues after different heat treatments. The final decomposition of the organic components occurred at ∼650°C. However, hydrated–carbonated secondary phase(s) were detected by FTIR in powders that had been heated at 700°C, indicating that the NKN nanopowders are susceptible to a reaction with atmospheric moisture and carbon dioxide. The NKN particle sizes were in the range 50–150 nm after decomposition at 700°C. 相似文献
67.
Anirban Kundu Jaya Narayan Sahu Ghufran Redzwan M.A. Hashim 《International Journal of Hydrogen Energy》2013
Bio-electrohydrogenesis through Microbial Electrolysis Cell (MEC) is one of the promising technologies for generating hydrogen from wastewater through degradation of organic waste by microbes. While microbial activity occurs at anode, hydrogen gas is evolved at the cathode. Identifying a highly efficient and low cost cathode is very important for practical implication of MEC. In this review, we have summarized the efforts of different research groups to develop different types of efficient and low cost cathodes or cathode catalysts for hydrogen generation. Among all the materials used, stainless steel, Ni alloys Pd nanoparticle decorated cathode are worth mentioning and have very good efficiency. Industrial application of MEC should consider a balance of availability and efficiency of the cathode material. 相似文献
68.
A methodology is proposed for optimal design of groundwater quality monitoring networks under epistemic uncertainty. The proposed
methodology considers spatiotemporal pollutant concentrations as fuzzy numbers. It incorporates fuzzy ordinary kriging (FOK)
within the decision model formulation for spatial estimation of contaminant concentration values. A multiobjective monitoring
network design model incorporating the objectives of fuzzy mass estimation error and spatial coverage of the designed network
is developed. Nondominated Sorting Genetic Algorithm-II (NSGA-II) is used for solving the monitoring network design model.
Performances of the proposed model are evaluated for hypothetical illustrative system. Evaluation results indicate that the
proposed methodology perform satisfactorily under uncertain system conditions. These performance evaluation results demonstrate
the potential applicability of the proposed methodology for optimal groundwater contaminant monitoring network design under
epistemic uncertainty. 相似文献
69.
Electrospinning can produce tissue‐engineering scaffolds possessing appropriate strength, biomimetic structure, economic appeal, and biocompatibility. To investigate how microstructural changes could potentially affect adherent mammalian cells, tensile samples were strained to 10, 40, and 80% extension, and adhered to double‐sided carbon tape to maintain specific states of strain. While establishing the stress–strain response, we invoked polymer sintering to help verify that the “point bonding” concept is more significant than previously realized at both the macroscopic and microscopic length scales. Sintering successfully established the effects of deliberate, extensive point bonding/localized “notch” generation on mechanical properties and microstructural response without requiring chemical changes within the structure. We also found that fibers experience significant hysteresis in terms of their orientation following exposure to high values of strain. Aligned fibers provide higher strengths (σave = 2.8 ± 0.3 MPa vs. σave = 1.29 ± 0.04 MPa for unaligned fibers) but considerably lower elongation [εave = (30 ± 2)% vs. εave = (102 ± 6)%]. Conversely, when strain occurs perpendicular to the aligned fiber direction total strain increases [εave = (188 ± 6)%] while strength decreases (σave = 0.38 ± 0.01 MPa). Elastic response to low strains appears to estimate ultimate tensile strength. In many ways, electrospun fibers behave similarly to classic interpretations of polymer chains in that when strained in both cases elements can rearrange and translate to align along the direction of loading. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007 相似文献
70.