A Personalized Multifunctional 3D Printed Shape Memory-Displaying,Drug Releasing Tracheal Stent

The ability to engineer custom-made medical devices and to implant them minimally invasively are two important trends in modern surgery. The personalization of the device is achieved by 3D printing it, while the capacity to deploy it minimally invasively harnesses the shape memory behavior displayed by the inks used. This study introduces a 3D printed, shape memory-displaying tracheal stent based on novel, flexible photo-polymerizable inks comprising polypropylene glycol/polycaprolactone triblocks. This research introduces the in situ welding strategy, whereby thin and flexible layers of the stent are separately printed, sequentially deployed, and then welded together at the tracheal site. By doing so, the insertion profile of the device is dramatically reduced and its flexibility largely increased. Porous stents are 3D printed seeking to prevent mucus plugging. By combining more than one ink, their properties are further fine-tuned. Polyethylene glycol chains are covalently bonded to the stent surface to minimize biofilm formation, an important drawback of current tracheal stents. The in vitro cell viability and cell adhesion behavior of the treated surfaces reveal their compatibility and anti-adhesive behavior. In order to prevent implant-related infections, ciprofloxacin is added to the ink, and released in vitro over time, rendering the stent with antibacterial activity.     

Analysis of the reference accidental sequence for safety assessment of LLCB TBM system

Safety analysis of the reference accidental sequence has been carried out for Lead Lithium cooled Ceramic Breeder (LLCB) Test Blanket Module (TBM) system; India's prototype of DEMO blanket concept for testing in International Thermonuclear Experimental Reactor (ITER). The accidental event analyzed starts with a Postulated Initiating Event (PIE) of ex-vessel loss of first wall helium coolant due to guillotine rupture of coolant pipe with simultaneous assumed failure of plasma shutdown system. Three different variants of the sequences analyzed include simultaneous additional failures of TBM and ITER first wall, failure of TBM box resulting in to spilling of lead lithium liquid metal in to vacuum vessel and reactor trip on Loss of Coolant Accident (LOCA) signal from TBM system. The analysis address specific reactor safety concerns, such as pressurization of confinement buildings, vacuum vessel pressurization, release of activated products and tritium during these accidental events and hydrogen production from chemical reactions between lead–lithium liquid metal and beryllium with water. An in-house customized computer code is developed and through these deterministic safety analyses the prescribed safety limits are shown to be well within limits for Indian LLCB-TBM design and it also meets overall safety goal for ITER. This paper reports transient analysis results of the safety assessment.     

A Grid‐enabled problem‐solving environment for advanced reservoir uncertainty analysis

Uncertainty analysis is critical for conducting reservoir performance prediction. However, it is challenging because it relies on (1) massive modeling‐related, geographically distributed, terabyte, or even petabyte scale data sets (geoscience and engineering data), (2) needs to rapidly perform hundreds or thousands of flow simulations, being identical runs with different models calculating the impacts of various uncertainty factors, (3) an integrated, secure, and easy‐to‐use problem‐solving toolkit to assist uncertainty analysis. We leverage Grid computing technologies to address these challenges. We design and implement an integrated problem‐solving environment ResGrid to effectively improve reservoir uncertainty analysis. The ResGrid consists of data management, execution management, and a Grid portal. Data Grid tools, such as metadata, replica, and transfer services, are used to meet massive size and geographically distributed characteristics of data sets. Workflow, task farming, and resource allocation are used to support large‐scale computation. A Grid portal integrates the data management and the computation solution into a unified easy‐to‐use interface, enabling reservoir engineers to specify uncertainty factors of interest and perform large‐scale reservoir studies through a web browser. The ResGrid has been used in petroleum engineering. Copyright © 2008 John Wiley & Sons, Ltd.     

Synthesis and characterization of styrene butadiene rubber—Bentonite clay nanocomposites

In the present study, naturally occurring unfractionated bentonite clay was used to prepare styrene butadiene rubber/bentonite clay nanocomposite by latex stage blending. The bentonite clay was organo‐modified by in situ resol formation by the reaction of resorcinol and formaldehyde. The latex clay mixture was co‐coagulated with acid. The resulting clay masterbatch was compounded and evaluated by Fourier Transform Infrared spectroscopy, X‐ray diffraction (XRD), Transmission Electron Microscopy (TEM), Energy Dispersive X‐ray spectroscopy (EDS), Scanning Electron Microscopy, Thermogravimetric analysis, and Differential Scanning Calorimetry. XRD showed that the interplanar distance of the in situ resol‐modified bentonite clay increased from 1.23 to 1.41 nm for the unmodified bentonite. TEM analysis indicated partial exfoliation and/or intercalation. EDS (Si and Al mapping) of the clay revealed the nature of the dispersion in the nanocomposites vis‐à‐vis the conventional styrene‐butadiene rubber (SBR)/bentonite clay composite. Thermogravimetric analysis was used to compare the decomposition trends of the SBR/clay nanocomposites with the SBR/clay composite. The glass transition temperature of SBR/clay nanocomposites increased as compared with that of neat SBR. Substantial improvement in most of the other mechanical properties was also observed in case of the nanocomposites. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers     

棉织物还原染料室温连续染色

探讨了使用亚铁盐与两种配体配位的络合物对棉织物室温还原染料连续和半连续染色。将所得结果与现有的硫酸氢盐方法作了比较。出于不同浸轧-显色的结果研究,在每一种体系（酒石酸／柠檬酸）中两种湿显色结果表现出均匀的染色效果。     

Assessment of cow dung as a supplementary fuel in a downdraft biomass gasifier

A model of downdraft gasifier has been described considering thermodynamic equilibrium of species in the pyro-oxidation zone and kinetically controlled reduction reactions in the reduction zone. It is found that the sole use of cow dung as the gasifier fuel is not technically feasible. This is due to very low heating value of the producer gas with much carbon leaving the gasifier as char. However, cow dung can be used as a supplementary fuel blended with a conventional woody biomass, like sawdust. The increased fraction of cow dung in the fuel blend renders the gasification process less efficient, when the gasifier is operated at a particular equivalence ratio. Both the producer gas production rate and its heating value reduce with the increase in the cow dung content in the biomass fuel blend, leading to an overall reduction in the gasifier conversion efficiency. It is observed that an increase in the cow dung content from 0 to 90% in the blended fuel reduces the heating value by 46.8% and the conversion efficiency by 45%. The use of cow dung in between 40 and 50% by mass in the fuel mix would result in an overall fuel economy.     

Effect of ZnO seed layer on the catalytic growth of vertically aligned ZnO nanorod arrays

We have grown vertically aligned ZnO nanorods and multipods by a seeded layer assisted vapor–liquid–solid (VLS) growth process using a muffle furnace. The effect of seed layer, substrate temperature and substrate material has been studied systematically for the growth of high quality aligned nanorods. The structural analysis on the aligned nanorods shows c-axis oriented aligned growth by homoepitaxy. High crystallinity and highly aligned ZnO nanorods are obtained for growth temperature of 850–900 °C. Depending on the thickness of the ZnO seed layer and local temperature on the substrate, some region of a substrate show ZnO tetrapod, hexapods and multipods, in addition to the vertically aligned nanorods. Raman scattering studies on the aligned nanorods show distinct mode at ∼438 cm⁻¹, confirming the hexagonal wurtzite phase of the nanorods. Room temperature photoluminescence studies show strong near band edge emission at ∼378 nm for aligned nanorods, while the non-aligned nanorods show only defect-emission band at ∼500 nm. ZnO nanorods grown without the seed layer were found to be non-aligned and are of much inferior quality. Possible growth mechanism for the seeded layer grown aligned nanorods is discussed.     

Uncertainty in estimating renewable energy utilisation potential: a case of solar thermal power generation in India

Estimation of renewable energy utilisation potential is important for identification of niche areas and prioritisation amongst different options. However, large variation in the potential estimates has been observed in different studies for the same renewable energy technology. This study is an attempt to analyse such a variation in the estimated potential for solar thermal power generation in India. From the analysis of three studies, it is found that the values of input parameters and the assumptions made substantially affect the estimated potential. The estimates of the utilisation potential depend upon the categories of wastelands selected, the chosen values of threshold DNI and wind speed as well as the criteria used for allocating suitable wastelands between solar photo-voltaic (PV) and thermal power generation. It is therefore critically important that reported values of renewable energy utilisation potential be interpreted and used with full cognisance of assumptions made and input parameters used in estimation.     

Shunt compensation

This article has surveyed some of the most important techniques used to generate the reference current for the shunt-type APF (active power filter). The GA-based approach is discussed in detail. Zero-crossing detection of one of the source voltages is sufficient, and the PLL may be removed. An ANN-based PI controller is added for faster buildup of the voltage across the capacitor. Faster control of the capacitor-voltage reduces the size of the capacitor and also improves the bandwidth of the controller. The proposed technique is simulated (in Simulink) and is also experimentally confirmed by developing a dSPACE1104-based prototype. With the availability of low-cost and high-speed processors, such computationally extensive methods are expected to be popular in the future.