Insertion of Vertically Aligned Nanowires into Living Cells by Inkjet Printing of Cells

Effective insertion of vertically aligned nanowires (NWs) into cells is critical for bioelectrical and biochemical devices, biological delivery systems, and photosynthetic bioenergy harvesting. However, accurate insertion of NWs into living cells using scalable processes has not yet been achieved. Here, NWs are inserted into living Chlamydomonas reinhardtii cells (Chlamy cells) via inkjet printing of the Chlamy cells, representing a low‐cost and large‐scale method for inserting NWs into living cells. Jetting conditions and printable bioink composed of living Chlamy cells are optimized to achieve stable jetting and precise ink deposition of bioink for indentation of NWs into Chlamy cells. Fluorescence confocal microscopy is used to verify the viability of Chlamy cells after inkjet printing. Simple mechanical considerations of the cell membrane and droplet kinetics are developed to control the jetting force to allow penetration of the NWs into cells. The results suggest that inkjet printing is an effective, controllable tool for stable insertion of NWs into cells with economic and scale‐related advantages.     

Personality and its effects on learning performance: Design guidelines for an adaptive e-learning system based on a user model

An increasingly widespread interest in developing fully adaptable e-learning systems (e.g., intelligent tutoring systems) has led to the development of a wide range of adaptive processes and techniques. In particular, advances in these systems are based on optimization for each user's learning style and characteristics, to enable a personalized learning experience. Current techniques are aimed at using a learner's personality traits and its effect on learning preferences to improve both the initial learning experience and the information retained (e.g., top-down or bottom-up learning organization). This study empirically tested the relationship between a learner's personality traits, analyzed the effects of these traits on learning preferences, and suggested design guidelines for adaptive learning systems. Two controlled experiments were carried out in a computer-based learning session. Our first experiment showed a significant difference in the learning performance of participants who were identified as introverts vs. those who were identified as being extroverts, according to the MBTI scale. As the distinction between extroverted personality types vs. introverted personality types showed the strongest correlation in terms of different learning styles, we used this criteria in our second experiment to determine whether design guidelines for appropriate content organization could reinforce the aforementioned correlation between personality type and learning experience.     

Properties of surface treated transparent conducting single walled carbon nanotube films

Transparent conducting single-walled carbon nanotube (SWCNT) films were fabricated using the spin coating technique. UV-ozone treated and poly(3,4-ethylenedioxythiophene) doped with poly(styrenesulfonate) coated glass substrates together with SWCNT dispersed in 1,2-dichlorobenzene were used to promote the adhesion of SWCNT at room temperature. The produced film had a sheet resistance of 430 Ω/□ for 80% optical transparency at 550 nm. The spin coated SWCNT film after a post fabricated treatment in a mixer of isopropyl alcohol and nitric acid solution had a sheet resistance as low as 120 Ω/□ for 80% optical transparency at 500 nm. Besides reduction in sheet resistance, we obtained stable and strongly adherent SWCNT films on substrate that could serve as an alternative to transparent conducting oxides in display and optoelectronic applications.     

Optimization of the influential factors for the improvement of CO2 utilization efficiency and CO2 mass transfer rate

Microalgae fix CO₂ as energy source and afford biomass and high valued products such as carotenoids, pigments, proteins, and vitamins that can be used for the production of nutraceuticals, pharmaceuticals, animal feed additives, cosmetics, etc. Carbon dioxide is the sole source of carbon and it is supplied continuously for the microalgal cultivation. But undissolved CO₂ is lost by outgassing and sufficient dissolved CO₂ should be provided to avoid carbon limitation. The effect of CO₂ mass transfer with different CO₂ concentrations, aeration rate of gas, bubble size, baffle type and baffle number on the growth of Chlorella sp. AG10002 was investigated and the optimized conditions for the enhancement of biomass productivity were determined. We confirm that these results can be provided as basic data to improve the CO₂ mass transfer ability for the high density culture of Chlorella sp. and some microalgae having commercial value.     

Development and application of gas hydrate reservoir simulator based on depressurizing mechanism

Natural gas hydrates are known to occur in vast quantities at the ocean floor or in permafrost regions. In-situ hydrate contains great volumes of methane gas, which indicates a potential future energy resource. In this study, we have developed a three-dimensional, multi-phase (gas, water, and hydrate) flow finite-difference model by using implicit pressure explicit saturation technique in order to investigate simultaneous flow through ice-liked hydrate reservoir. The developed model is based on the depressurizing method as producing mechanism. The model evaluates local gas generation dissociated from the hydrate with the aid of kinetic dissociation theory proposed by Kim-Bishnoi. The computation of kinetic dissociation uses the empirical dissociation rate as a function of specific surface area between phases and pressure difference. With the developed model, a one-dimensional system has been simulated for analyzing the production performance of a hydrate reservoir and for investigating the effect of hydrate saturation on absolute permeability and relative permeability characteristics. Also, for the three-dimensional field-scaled reservoir system, a number of numerical exercises have been conducted to understand the effect of mass transfer and to characterize the flowing mechanism under the conditions of increased permeability resulting from the dissociation hydrate.     

Effect of tris(methoxy diethylene glycol) borate on ionic conductivity and electrochemical stability of ethylene carbonate-based electrolyte

The effect of tris(methoxy diethylene glycol) borate (TMDGB) on the coordination structure between ethylene carbonate (EC) solvents with high permittivity and ClO₄⁻ anions has been investigated by using a Fourier transform infrared (FT-IR) spectroscopy. The results of FT-IR analyses manifested that the boron atom of TMDGB anion receptor forms the complex with ClO₄⁻ anions. Even though Lewis acid-base interaction between the TMDGB anion receptor and ClO₄⁻ anions in the electrolyte solution lead to the prominent enhancement of both the dissociation degree of lithium salts and the lithium ion transference number, the ionic conductivity of the EC-based electrolyte solution decreased due to the trap of ClO₄⁻ anions by introducing the TMDGB anion receptor.The electrochemical stability of gel polymer electrolyte based on semi-interpenetrating network (IPN) structure with tris(pentafluoro phenyl) borane (TPFPB) or TMDGB anion receptor was obviously improved.     

Stable single-frequency fiber ring laser for 25-GHz ITU-T grids utilizing saturable absorber filter

A stable single-frequency fiber ring laser is proposed that operates in a single mode for more than an hour by incorporating unpumped erbium-doped fiber (EDF) as a saturable absorber filter and optimizing the length of EDF used as gain medium. This laser can be continuously tuned to 25-GHz spacing that precisely matches the ITU-T grids by temperature control of etalon filter. This laser had a signal-to-source spontaneous emission ratio higher than 70 dB, and lasing frequencies of 361 channels was matched to ITU-T grids with excellent flatness. Frequency offset from the ITU-T grid was less than 0.14 GHz. The linewidth and the relative intensity noise value was less than 1.3 kHz and 130 dB/Hz (above 250 kHz), respectively.     

A model on desulfurization characteristics of an entrained bed-bubbling bed hot gas cleanup system for IGCC

A mathematical model has been developed to predict performance of a continuous entrained-bed and bubbling fluidized-bed hot gas desulfurization system in IGCC. The model combines the particle residence time with the kinetic rate in each reactor. The model has been applied to the KIER’s laboratory scale fluidized bed process. The present model provided a reasonable fit in predicting experimental results that the outlet concentration of H₂S from the desulfurizer and SO₂ from the regenerator increased nearly proportionally to the inlet concentration of H₂S to the desulfurizer. The model also could predict well the outlet concentration of O₂ from the regenerator to decrease as the inlet concentration of H₂S to the desulfurizer increased. The present model predicted with reasonable accuracy mean diameter of bed particles and sulfur content of particles in desulfurizer and regenerator.     

Chemical-looping combustion of syngas by means of spray-dried NiO oxygen carrier

Chemical-looping combustion (CLC) of syngas has a potential to generate power economically with achieving the inherent carbon dioxide capture. An oxygen carrier with high reactivity and excellent physical properties would make CLC technology more competitive. In this work, oxygen carrier with 70 wt% NiO was prepared by spray drying technique. The prepared oxygen carrier had excellent physical properties for fluidized-bed application of CLC process. The reactivity of the oxygen carrier in repeated reduction-oxidation was measured by thermogravimetric analyzer with simulated syngas. Oxygen carrier calcined at 1,100 °C showed high oxygen transfer capacity of 14.7 wt%, utilizing 98% of the transferable oxygen. Oxygen transfer capacity and oxygen transfer rate was increased with the increase of reaction temperature, and the highest oxygen transfer rate was observed when about half of the transferable oxygen reacted with syngas. The reduction rate of the syngas (mixture of H₂ and CO) appeared to be approximately the sum of the reaction rate of each fuel gas. The experimental results indicated that the spray-dried NiO oxygen carrier prepared in this work could be a good quality oxygen carrier for the CLC of syngas.     

Oxidation Characteristics and Oxide Layer Evolution of Alloy 617 and Haynes 230 at 900 °C and 1100 °C

To evaluate the oxidation resistance of Alloy 617 and Haynes 230, oxidation tests were performed at 900 °C and 1100 °C in air and helium environments. Scale characterizations were assessed on specimens exposed to air using thin-film XRD, XPS, SEM and EDX. Oxidation resistance was dependent on the stability of the surface oxide layer, which can be affected by minor alloying elements such as Ti and Mn. At 900 °C, for Alloy 617, a mixture of the extensive NiO–Cr₂O₃ double layer and isolated NiO–NiCr₂O₄–Cr₂O₃ triple layer were observed at a steady-state condition. For Haynes 230, a MnCr₂O₄ layer was formed on top of the Cr₂O₃ layer, resulting in a lower oxidation rate. At 1100 °C, both alloys showed a double layer consisting of an inner Cr₂O₃ and outer MnCr₂O₄ or TiO₂. The spallation of outer layer and subsequent volatilization of the Cr₂O₃ layer produced a rugged surface and interface as well as internal oxidation.