Zero-valent iron particles were prepared by wet reduction chemistry assisted with ultrasonic treatment. Such prepared particles have uniform size, exhibit crystalline structure and show strong pararnagnetic property. ...
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Zero-valent iron particles were prepared by wet reduction chemistry assisted with ultrasonic treatment. Such prepared particles have uniform size, exhibit crystalline structure and show strong pararnagnetic property. Their surface modification by coating poly(N-vinyl-2-pyrrolidone) (PVP) was investigated. The resulting Fe(0)-PVP particles were monodispersed and possessed enhancing magnetization saturation. Those synthesis conditions to control the particle size and distribution were exploited.
Professionalism, which includes engineering ethics, is recognized as a valued topic in industry and education but it is difficult to teach and assess. This paper presents a web-based professional responsibility instru...
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Ionic liquids have shown great promise as alternative green solvents. The low vapor pressure exhibited by ionic liquids offers an environmental benefit over many traditional solvents used in industrial processes. Howe...
ISBN:
(纸本)9781618397317
Ionic liquids have shown great promise as alternative green solvents. The low vapor pressure exhibited by ionic liquids offers an environmental benefit over many traditional solvents used in industrial processes. However, the toxicity of ionic liquids can still be a concern and must be considered when selecting a solvent. Ionic liquids can also degrade due to thermal decomposition or hydrolysis. Such factors should be taken into account when designing or selecting an ionic liquid solvent. The cation, anion, and alkyl chain length on the cation can be altered to design an ionic liquid with desired properties. These tunable properties show the promise of designing ionic liquids as environmentally friendly entrainers for the separation of azeotropes. With an ionic liquid entrainer designed or selected for a specific azeotrope mixture, an extractive distillation process can be subsequently designed. The design of ionic liquid entrainers for the separation of azeotropes has been investigated. The azeotropic systems considered were methanol-acetone, methanol-benzene, methanol-cyclohexane, water-ethanol, ethanol-benzene, and ethanol-cyclohexane. Several group contribution (GC) models were developed and used for the initial design and selection of candidate ionic liquids. Previously published experimental data was used in the development of the GC models. A solubility parameter model was used to optimally design cation, anion, and alkyl chain length combinations that were similar in value to the azeotrope mixture volume-fraction average solubility parameter value. Prediction intervals at 95% were used to represent the uncertainty in the predicted solubility parameter values and compare solutions to the design problem. Ionic liquid candidates were screened using a thermal decomposition temperature GC-model and several different GC-models for toxicity measures. Stable, non-toxic ionic liquids with optimal solubility parameter values were obtained. A UNIFAC activity coefficien
Highly enhanced and selective adhesion can be achieved between surfaces patterned with charges even when each one has no net charge. In this and a companion paper [C. Jin, Y. Bai, A. Jagota, and C.-Y. Hui, J. Appl. Ph...
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Throughout the past ten years global society has more of a vested interest in the research and development of sustainable energy sources. Carbon dioxide fixation and collection of biodiesel oils through the utilizatio...
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We have analyzed the statistical thermodynamics of peeling single-stranded DNA (ssDNA) from the surface of graphite. Using recently measured parameters, we represent ssDNA as a polymer chain strongly adsorbed to a fri...
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We have analyzed the statistical thermodynamics of peeling single-stranded DNA (ssDNA) from the surface of graphite. Using recently measured parameters, we represent ssDNA as a polymer chain strongly adsorbed to a frictionless substrate using the freely jointed chain, wormlike chain, and rotational isomeric state models. All three models predict steady peeling force under force control, in agreement with single-molecule experiments. We predict that, for finite-length chains, the force response has measurable spikes under displacement control. These force spikes carry information about the underlying sequence of ssDNA, which might thus be measurable with a sufficiently stiff loading system. For the freely jointed chain model, under force control, we have obtained several exact closed-form results and provide relations between the measured peel force and the underlying adhesion free energy.
Bioceramics are an important subclass of inorganic, non-metallic biomaterials. Attributing to their bioactivity and the ability to form bonds with native bone, bioceramics are increasingly used in medical implants, es...
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ISBN:
(纸本)0878492704
Bioceramics are an important subclass of inorganic, non-metallic biomaterials. Attributing to their bioactivity and the ability to form bonds with native bone, bioceramics are increasingly used in medical implants, especially for bone repair and regeneration. With chemical composition similar to that of native bone, hydroxyapatite (HAp), a type of bioceramics, may impart to biomaterial implants biocompatibility, osteoconductivity, as well as surface properties that are germane to osteointegration at the bone-implant interface. However, porous bioceramics are very brittle and have low fracture toughness and compressive strength, which limits their uses as bulk materials for orthopedic implants. Increasing their mechanical strength by reducing the porosity may prevent tissue infiltration, therefore, bone regeneration. In comparison, polymers may mimic the mechanical properties of native bone, however, may lack the appropriate surface properties to seamlessly integrate with natural bone. There is a critical need to combine the bulk properties of polymers with the surface properties of bioceramics in the design of functional scaffolds for bone tissue engineering. There are several ways to incorporate bioceramics on scaffold surfaces, including plasma spraying, sputter coating, physical adsorption, laser deposition, and biomineralization. Biomineralization, which allows easy fabrication of bioceramics under physiological conditions, provides an effective means to produce bonelike minerals, e.g., HAp, on scaffold surfaces. By following the cascade of biological mineralization in vivo, biomineralization in vitro on polymers may be achieved using several different methods, including immersion in simulated body fluid (SBF), alternative soaking in calcium and phosphate solutions, urea-mediated solution mineralization, enzymatic method, and direct incorporation of HAp nanoparticles into polymers. The uniformity, structure, and composition of the bioceramic coatings can be fine
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