Zeolite‐Coated Porous Arrays: A Novel Strategy for Enzyme Encapsulation

Zeolite Beta‐coated stainless steel supports with gradient porosity are employed as filter‐panels for lipase encapsulation. Enzyme encapsulation on the stainless steel porous discs is achieved via vacuum infiltration. Subsequently, two lipase‐encapsulated zeolite Beta‐coated stainless steel discs are attached using an adhesive. The zeolite Beta layer on the stainless steel discs largely prevents lipase leaching in comparison to the stainless steel discs without a zeolite layer. The activity of the lipase‐encapsulated, attached zeolite Beta‐coated stainless steel porous discs depends on the thickness of the zeolite Beta layer. It is shown that the biocatalytic performance of the lipase‐encapsulated, attached zeolite Beta‐coated stainless steel supports with a zeolite Beta layer thickness of ≈0.7–1 μm is better than the lipase‐encapsulated, attached zeolite Beta‐coated stainless steel supports with a zeolite Beta layer thickness of ≈2–3 μm in the lipase‐catalyzed transesterification of vinyl propionate with 1‐butanol using n‐hexane as solvent.     

Novel Glass‐Ceramic Composition as Sealant for SOFCs

This work deals with the design, the characterization, and testing of a novel glass‐ceramic to be used as sealant for planar solid oxide fuel cells and its compatibility with Mn_1.5Co_1.5O₄‐coated Crofer22APU. Thermal, sintering, and crystallization behavior and thermo mechanical properties of the sealant are reviewed and discussed, indicating therefore that these compositions can be deposited at 850°C and provide an excellent compatibility with both the Mn_1.5Co_1.5O₄‐coated Crofer22APU and the anode‐supported electrolyte. In particular, Mn_1.5Co_1.5O₄‐coated Crofer22APU/sealant/anode‐supported‐electrolyte joined samples have been submitted to thermal tests (in air atmosphere) from RT to 800°C (SOFC operating temperature) up to 500 h. No interactions, cracks formation, or failure were observed at the Mn_1.5Co_1.5O₄‐coated Crofer22APU/sealant interface and between the glass‐ceramic and the anode‐supported‐electrolyte after 500 h of thermal tests in air atmosphere.     

Optical absorption spectrum of rotated trilayer graphene

Using ab initio calculations we have studied the optical linear response of different configurations of twisted trilayer graphene systems. We have found that when one of the outer layers is rotated the system shows an angle-dependent optical spectrum as its twisted bilayer counterpart; however, in this case there are two absorption peaks located in the visible range of the spectrum and one more in the intermediate infrared range for large relative rotation angles. When two layers are rotated the spectrum exhibits only two absorption peaks in the visible range revealing information about the two relative rotation angles between the layers in the structure. All these absorption peaks in the visible range shift to the intermediate infrared range for small angles.     

Investigation of laser ablation on boron emitters for n‐type rear‐junction PERT type silicon wafer solar cells

n‐type silicon wafer solar cells are receiving increasing attention for industrial application in recent years, such as the n‐type rear‐junction Passivated Emitter Rear Totally‐diffused (PERT) solar cells. One of the main challenges in fabricating the n‐PERT solar cells is the opening of the rear dielectric for localized contacts. In this work laser ablation is applied to locally ablate the rear dielectric. We investigate the laser damage to the emitter at the laser‐ablated regions using the emitter saturation current density, J_0e,laser, extracted by two approaches. J_0e,laser is observed to be injection dependent due to high J₀₂ recombination caused by laser damage to the space charge region. By using the optimized laser ablation parameters, n‐PERT solar cells with an efficiency of up to 21.0% are realized. Copyright © 2015 John Wiley & Sons, Ltd.     

Superhydrophobic ZnO networks with high water adhesion

ZnO structures were deposited using a simple chemical bath deposition technique onto interdigitated electrodes fabricated by a conventional photolithography method on SiO₂/Si substrates. The X-ray diffraction studies show that the ZnO samples have a hexagonal wurtzite crystalline structure. The scanning electron microscopy observations prove that the substrates are uniformly covered by ZnO networks formed by monodisperse rods. The ZnO rod average diameter and length were tuned by controlling reactants'' concentration and reaction time. Optical spectroscopy measurements demonstrate that all the samples display bandgap values and emission bands typical for ZnO. The electrical measurements reveal percolating networks which are highly sensitive when the samples are exposed to ammonia vapors, a variation in their resistance with the exposure time being evidenced. Other important characteristics are that the ZnO rod networks exhibit superhydrophobicity, with water contact angles exceeding 150° and a high water droplet adhesion. Reproducible, easily scalable, and low-cost chemical bath deposition and photolithography techniques could provide a facile approach to fabricate such ZnO networks and devices based on them for a wide range of applications where multifunctionality, i.e., sensing and superhydrophobicity, properties are required.

PACS

81.07.-b; 81.05.Dz; 68.08.Bc     

Differential dyeing of wool fabric with metal‐complex dyes after ultraviolet irradiation

Experiments were conducted to investigate the ultraviolet irradiation of wool fabric as a pretreatment for differential dyeing. Wool fabric was irradiated using a medium‐pressure mercury lamp in order to obtain, on the irradiated area, increased dye uptake under the same dyeing conditions as untreated wool. The chemical modification of the fibre surface as a result of ultraviolet irradiation was confirmed by an increase in metal ion absorption and hydrophilicity, in agreement with Fourier Transform‐infrared–attenuated total reflectance spectra, although scanning electron microscopy showed that the fibre morphology was unaffected. A selection of 1:1 metal‐complex dyes was used to show the maximum colour difference between irradiated and untreated areas of the fabric. The experiments focused on two effects: a double face with the same shade but different depths (greater depth on the treated side), and a double face with different shades. The latter effect was achieved by dyeing the irradiated fabrics with mixtures of acid and metal‐complex dyes. Rubbing and washing fastness evaluations at 50 °C confirmed that the dyeings after irradiation with the selected 1:1 metal‐complex dyes scored identically to conventional dyeings.     

Getting more from success: Standard raising as esteem maintenance.

In 4 studies, the authors tested the hypothesis that success prompts standard raising and that doing so helps maintain performance-related esteem by augmenting perceptions of competence. Study 1 showed that students raised examination standards following success in meeting them. In Study 2, professors who were recently promoted to tenure raised what they thought were the publication standards at their university, compared with the standards of their nonpromoted counterparts. Supporting the authors' esteem-maintenance account, participants in Study 3 reported that they would feel better meeting a high standard by a small margin than meeting a low standard by a large margin, and competence attributions mediated this relationship. Participants in Study 4 raised standards when their esteem was threatened but not when it was affirmed, also supporting an esteem-maintenance account. Alternative interpretations of standard raising, including goals for future improvement and initial standard lowering, were not supported in these studies. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Optimization of β-Glucosidase, β-Xylosidase and Xylanase Production by Colletotrichum graminicola under Solid-State Fermentation and Application in Raw Sugarcane Trash Saccharification

Efficient, low-cost enzymatic hydrolysis of lignocellulosic residues is essential for cost-effective production of bioethanol. The production of β-glucosidase, β-xylosidase and xylanase by Colletotrichum graminicola was optimized using Response Surface Methodology (RSM). Maximal production occurred in wheat bran. Sugarcane trash, peanut hulls and corncob enhanced β-glucosidase, β-xylosidase and xylanase production, respectively. Maximal levels after optimization reached 159.3 ± 12.7 U g⁻¹, 128.1 ± 6.4 U g⁻¹ and 378.1 ± 23.3 U g⁻¹, respectively, but the enzymes were produced simultaneously at good levels under culture conditions optimized for each one of them. Optima of pH and temperature were 5.0 and 65 °C for the three enzymes, which maintained full activity for 72 h at 50 °C and for 120 min at 60 °C (β-glucosidase) or 65 °C (β-xylosidase and xylanase). Mixed with Trichoderma reesei cellulases, C. graminicola crude extract hydrolyzed raw sugarcane trash with glucose yield of 33.1% after 48 h, demonstrating good potential to compose efficient cocktails for lignocellulosic materials hydrolysis.     

Service life prediction of exterior cladding components under standard conditions

An empirical method was developed for the prediction of the service life of building components, based on an evaluation of their actual performance and on the identification of failure mechanisms affecting their durability. The service life of exterior components subjected to normal service conditions is predicted. Four types of exterior claddings are exemplified: cementitious mortar, synthetic rendering, ceramic mosaic, and wet‐fixing stone cladding. The proposed prediction models yield high degrees of fit to the data (R ² in the range of 0.86 to 0.93 at a 0.0001 level of significance). Life cycle costs (LCC) analysis – following service‐life prediction results – leads to the conclusion that maintenance and replacements costs account for 10–80% of initial capital costs. Synthetic rendering exhibited the highest LCC effectiveness, reflecting durability and low capital costs. The method can be used for planning preventive maintenance, evaluating economic implications of failures, and planning service life.