Simultaneously achievement of high recoverable energy density and efficiency in sodium niobate-based ceramics

Journal of Materials Science: Materials in Electronics - Single lead-free Na0.73Bi0.09(Nb1???xTax)O3 (x?=?0, 0.10, 0.20, 0.30, and 0.40) ceramic phases were processed...     

A knowledge construction methodology to automate case-based learning using clinical documents

The case-based learning (CBL) approach has gained attention in medical education as an alternative to traditional learning methodology. However, current CBL systems do not facilitate and provide computer-based domain knowledge to medical students for solving real-world clinical cases during CBL practice. To automate CBL, clinical documents are beneficial for constructing domain knowledge. In the literature, most systems and methodologies require a knowledge engineer to construct machine-readable knowledge. Keeping in view these facts, we present a knowledge construction methodology (KCM-CD) to construct domain knowledge ontology (i.e., structured declarative knowledge) from unstructured text in a systematic way using artificial intelligence techniques, with minimum intervention from a knowledge engineer. To utilize the strength of humans and computers, and to realize the KCM-CD methodology, an interactive case-based learning system(iCBLS) was developed. Finally, the developed ontological model was evaluated to evaluate the quality of domain knowledge in terms of coherence measure. The results showed that the overall domain model has positive coherence values, indicating that all words in each branch of the domain ontology are correlated with each other and the quality of the developed model is acceptable.     

Experimental Investigation of Two-Phase Pressure Drop in a Microchannel

Experimental results of two-phase pressure drop in a horizontal circular microchannel are reported in this paper. A test tube was made of fused silica having an internal diameter of 781 μm with a total length of 261 mm and a heated length of 191 mm. The outer surface of the test tube was coated with an electrically conductive thin layer of ITO (indium tin oxide) for direct heating of the test section. Refrigerants R134a and R245fa were used as the working fluids, and mass flux during the experiments was varied between 100 and 650 kg/m²-s. Experiments were performed at two different system pressures corresponding to saturation temperatures of 25°C and 30°C for R134a and at three different system pressures corresponding to saturation temperatures of 30°C, 35°C, and 40°C for R245fa. Two-phase frictional pressure drop characteristics with variation of mass flux, vapor fraction, saturation temperature, and heat flux were explored in detail. Finally, the prediction capability of some well-known correlations available in the literature, some developed for macrochannels and others especially developed for microchannels, was assessed.     

Process Optimization and Characterization of Popped Brown Rice

The popping process was optimized for brown rice based on an expansion ratio. A central composite design with interactive effect of three independent variables, including salt content (1–2.5 g/100 g raw material), moisture content (13–17 g/100 g raw material), and popping temperature (210–240°C) was used to study their effects on the expansion ratio of rice using response surface methodology. The experimental values of expansion ratio were ranged from 5.24 to 6.85. On fitting the experimental values of expansion ratio to a second order polynomial equation, a mathematical model with the predictability was developed with the statistical adequacy and validity (p ? 0.05). From the model, the optimal condition including salt content (1.75 g/100 g raw material), moisture content (15 g/100 g raw material), and popping temperature (225°C) were predicted for a maximum expansion ratio of 6.79, which was then proved to be 6.85 through experiment. Raw and popped brown rice were investigated for physical properties including hardness, L*, a*, and b* value, length/breadth ratio, bulk density, and minerals, which showed the significant differences. The optimized popped rice sample was evaluated for structural, spectroscopic, and thermal properties, which showed the significant difference from raw rice.     

Structure–property relationship of hetero‐aromatic‐electron‐donor antennas of polypyridyl Ru (II) complexes for high efficiency dye‐sensitized solar cells

Three novel heteroleptic amphiphilic polypyridyl Ru‐complexes, coded MH08–10 , with hetero‐aromatic electron‐donor ancillary ligands containing N‐benzylcarbazole ( MH08 ), dibenzofurane ( MH09 ) and benzothiophene moieties ( MH10 ) were synthesized to study the influence of different heterocyclic electron donors on the interrelationship of photophysical and electrochemical properties, and device performances for dye‐sensitized solar cells (DSSCs). MH08 showed a remarkably high molar extinction coefficient of 27,650 M⁻¹cm⁻¹. MH08–TBA was synthesized from MH08 by converted one COOH group into −COO⁻⁺N(C₄H₉)₄ to investigate the effect of deprotonating one carboxylic group on the Fermi level and electron injection. When compared under the same experimental device conditions using 0.3M t‐butylpyridine (TBP), the short‐circuit photocurrent density (J_SC) and total conversion efficiency (%η) of MH08–10 were MH08 > MH09 > MH10 . The differences in %η and J_SC of MH08–10 were ascribed to the conjugation length coupled with the electron donation and hole‐transport strength of the ancillary ligands, which were in the following order N‐benzylcarbazole>dibenzofurane>benzothiophene. Moreover, MH08–TBA showed J_SC of 19.56 mAcm⁻² and %η of 9.76% compared to 17.16 mAcm⁻² and 9.12% of the benchmark dye N719 . The superior performance of MH08–TBA was attributed to its better light harvesting and enhanced incident‐photon‐to‐current efficiency (IPCE) conversion. DFT/TD‐DFT calculations utilizing the energy functional B3LYP and the full‐electron basis set DGDZVP were performed to calculate HOMO and LUMO energies, vertical electronic excitations, lowest singlet‐singlet electronic transitions (E_0‐0), and excited state oxidation potentials. Excellent agreement was found between the experimental results and calculated data. Copyright © 2013 John Wiley & Sons, Ltd.     

Luminescence from praseodymium doped AlN thin films deposited by RF magnetron sputtering and the effect of material structure and thermal annealing on the luminescence

Thin films of Praseodymium doped AlN are deposited on silicon (111) substrates at 77 K and 950 K by rf magnetron sputtering method. About 500–1000 nm thick films are grown at 100–200 watts RF power and 5–8 mTorr nitrogen, using a metal target of Al with Pr. X-rays diffraction results show that films deposited at 77 K are amorphous and those deposited at 950 K are crystalline. Cathodoluminescence studies are performed at room temperature and luminescence peaks are observed in a wide range from ultraviolet to infrared region. The most intense peak is obtained in green at 526 nm from amorphous films as a result from ³P₁→³H₅ transition. In crystalline films the intense peak was obtain in red at 648 nm as a result from ³P₀→³F₂ transition. Films are thermally activated at 1300 K for half an hour in a nitrogen atmosphere. Thermal activation enhances the intensity of luminescence. Two peaks at 488 nm and 505 nm merged after thermal activation, giving rise to a single peak at 495 nm.     

Smart Innovation Engineering: Toward Intelligent Industries of the Future

ABSTRACT

Knowledge-based engineering systems are founded upon integration of knowledge into computer systems and are one of the core requirements for the future Industry 4.0. This paper presents a system called smart innovation engineering (SIE) capable of facilitating product innovation process semi-automatically. It enhances decision-making processes using the explicit knowledge of formal decision events. The SIE system carries the promise to support the innovation processes of manufactured products in a quick and efficient way. It stores and reuses past decisional events or sets of experiences related to innovation issues, which significantly enhances innovation progression. The analysis of basic concepts and implementation method proves that SIE system is an advanced form of cyber physical systems. It is flexible, systematic, fast, and supports customization. It can play a vital role toward Industry 4.0 development.     

Synthesis,characterization, and cell viability of bifunctional medical-grade polyurethane nanofiber: Functionalization by bone inducing and bacteria ablating materials

There is an extensive possibility of improving characteristics of fibers used in hard tissue engineering, being hydrophobic and less osteoconductive, resulting in the dynamic growth of new tissues. The current work focuses on the fabrication of nanofibers incorporated with titanium dioxide (TiO₂) ''as osteoconductive'' and silver (Ag) ''as self-healing'' nanoparticles (NPs). The incorporation of AgNO₃ by in situ method not only helped to impart the antibacterial activity but also changed the contact angle from 81 ± 03° in the case of pristine nanofibers to 74 ± 03°, 61 ± 03°, 50 ± 08°, and 39 ± 1.1°, in the composite scaffolds containing 0.01, 0.03, 0.05, and 0.07 M of Ag salts. The incubation in simulated body fluid at 37°C to induce mineralization on nanofiber scaffolds indicated Ca and P crystals' formation. The antibacterial activity showed significantly more toxicity toward E. coli (8.3 ± 0.9 mm) than S. aureus (1.2 ± 0.1 mm). Biocompatibility studies using MTT assay on the pre-osteoblasts showed that both TiO₂ and Ag NPs present in the nanofibers are non-toxic to the bone-like cells. However, results show that a higher concentration of Ag NPs (i.e., 0.07 M) is toxic to cells growing. Finally, all the results suggest that the nanofiber scaffolds have considerable scope for future bone tissue engineering materials.     

Structural,Thermal and Luminescence Properties of AlN:Tm Thin Films Deposited on Silicon Substrate and Optical Fiber

Semiconductors - Thin films of AlN:Tm are deposited on a Si(111) and Si(100) substrates and optical fiber by rf magnetron sputtering method. 200–400 nm thick films are deposited at various...     

Intense Red Catho- and Photoluminescence from 200 nm Thick Samarium Doped Amorphous AlN Thin Films

Samarium (Sm) doped aluminum nitride (AlN) thin films are deposited on silicon (100) substrates at 77 K by rf magnetron sputtering method. Thick films of 200 nm are grown at 100–200 watts RF power and 5–8 m Torr nitrogen, using a metal target of Al with Sm. X-ray diffraction results show that films are amorphous. Cathodoluminescence (CL) studies are performed and four peaks are observed in Sm at 564, 600, 648, and 707 nm as a result of ⁴G_5/2 → ⁶H_5/2, ⁴G_5/2 → ⁶H_7/2, ⁴G_5/2 → ⁶H_9/2, and ⁴G_5/2 → ⁶H_11/2 transitions. Photoluminescence (PL) provides dominant peaks at 600 and 707 nm while CL gives the intense peaks at 600 nm and 648 nm, respectively. Films are thermally activated at 1,200 K for half an hour in a nitrogen atmosphere. Thermal activation enhances the intensity of luminescence.