Highly Active Fe3O4@SBA-15@NHC-Pd Catalyst for Suzuki–Miyaura Cross-Coupling Reaction

Catalysis Letters - A novel Pd-NHC functionalized magnetic Fe3O4@SBA-15@NHC-Pd was synthesized and used as an efficient heterogeneous catalyst in the Suzuki–Miyaura C–C bond formation...     

Magnetically modified electrocatalysts for oxygen evolution reaction in proton exchange membrane (PEM) water electrolyzers

Green hydrogen production can only be realized via water electrolysis using renewable energy sources. Proton exchange membrane water electrolyzers have been demonstrated as the technology of choice for mass production of green hydrogen due to their scalability and potential high efficiency. However, the technology is still relatively expensive due to the catalyst materials cost and operational limitations due to mass transfer and activation polarizations. During the oxygen evolution reaction, oxygen bubbles stick to the electrode surface and this causes a low reaction rate and high mass transfer losses. In this study, the commonly used electrocatalyst for oxygen evolution reactions; IrO₂, is modified by introducing magnetic Fe₃O₄ to achieve greater bubble separation at the anode during operation. The prepared composite catalysts were characterized using Scanning Electron Microscope, Energy Dispersive X-Ray Analysis, X-Ray Powder Diffraction, X-ray photoelectron spectroscopy and Brunauer–Emmett–Teller characterization methods. The modified composite electrocatalyst samples are magnetized to investigate the magnetic field effect on oxygen evolution reaction performance in proton exchange membrane water electrolyzers. 90% IrO₂ - 10% Fe₃O₄ and 80% IrO₂ - 20% Fe₃O₄ samples are tested via linear sweep voltammetry both ex-situ and in-situ in a proton exchange membrane water electrolyzer single cell. According to the linear sweep voltammetry tests, the magnetization of the 80% IrO₂ - 20% Fe₃O₄ sample resulted in 15% increase in the maximum current density. Moreover, the single cell electrolyzer test showed a four-fold increase in current density by employing the magnetized 80% IrO₂ - 20% Fe₃O₄ catalyst.     

Natural contamination of cyclopiazonic acid in dried figs and co-occurrence of aflatoxin

Natural cyclopiazonic acid (CPA) and aflatoxin (AF) contamination were investigated in Aspergillus section Flavi positive dried fig samples collected from orchards after harvesting. Cyclopiazonic acid and AF were determined by thin layer chromatography (TLC) and high performance liquid chromatography (HPLC), respectively. Cyclopiazonic acid was found in all samples of dried figs that contain AF. Cyclopiazonic acid and AF co-occurred in 23% of the samples. The number of dried fig samples contaminated with CPA was higher than the samples containing AF. Therefore CPA was a more common mycotoxin than AF in dried figs. To the best of our knowledge, this is the first report of CPA and co-occurrence of CPA and AF in dried figs.     

Distance similarity matrix using ensemble of dimensional data reduction techniques: Vibration and aerocoustic case studies

Vibration and acoustic-based health-monitoring techniques are used in the literature to monitor structural health under dynamic environment. In this paper, we propose a damage detection and monitoring method based on a distance similarity matrix of dimensionally reduced data wherein redundancy therein is removed. The matrix similarity approach is generic in nature and has the capability of multiscale representation of datasets. To extract damage-sensitive features, dimensional reduction techniques are applied and compared. An ensemble method of dimensional reduction feature outputs is presented and applied to two case studies. The results supports why ensembles can often perform better than any single-feature extraction method. For the first case study, aeroacoustic datasets are collected from controlled scaled experimental tests of controlled known damaged subscale wing structure. For the second case study, a vibration experiment study is used for abrupt change detection and tracking. The results of the two case studies demonstrate that the proposed method is very effective in detecting abrupt changes and the ensemble method developed here can be used for deterioration tracking.     

Postoperative patient-controlled epidural analgesia with opioid bupivacaine mixtures

PURPOSE: To determine the efficacy and safety of patient-controlled epidural analgesia of morphine or fentanyl in combination with bupivacaine for postoperative pain relief. METHODS: Forty ASA I-II patients scheduled for major abdominal surgery were studied. After insertion of a lumbar epidural catheter, patients were given a non-opioid general anaesthetic. After surgery patients complaining of pain, received a loading dose of 2 mg morphine (Group I) or 50 micrograms fentanyl (Group II). For continuing pain, 1 mg morphine in 4 ml bupivacaine 0.125% (0.25 mg.ml-1 morphine and 1 mg.ml-1 bupivacaine, Group I) or 20 micrograms fentanyl in 4 ml bupivacaine 0.125% (5 micrograms.ml-1 fentanyl and 1 mg.ml-1 bupivacaine Group II) were administered. Blood pressure, heart rate, respiratory rate and SpO2 were monitored. Assessments of pain (VAS), nausea-vomiting, motor block, pruritus and sedation were recorded for 24 hr. RESULTS: No difference in pain or sedation was observed between groups. The 24 hr postoperative opioid consumption was 15.50 +/- 7.53 mg morphine and 555.10 +/- 183.85 micrograms fentanyl. Total bupivacaine 0.125% consumption was 58.00 +/- 30.14 ml in Group I and 101.05 +/- 36.77 ml in Group II. One patient in Group II complained of motor weakness in one leg. The incidence of nausea (Group I 45%, Group II 10% P < 0.05) and pruritus (Group I 30%, Group II 5% P < 0.05) was less in patients receiving fentanyl. CONCLUSION: Both methods were effective in the prevention of pain but, because of fewer side effects, fentanyl may be preferable to morphine.     

Acrylic bone cements: Effects of the poly(methyl methacrylate) powder size and chitosan addition on their properties

The effect of the particle size of poly(methyl methacrylate) (PMMA) and the incorporation of chitosan (CH) on the mechanical and thermal properties and the biocompatibility of acrylic bone cements were investigated. Three groups of bone cements were prepared with different PMMA particles. Groups 1 (BC1) and 2 (BC2) contained ground and sieved PMMA with particle sizes in the ranges 50–150 μm and 1–50 μm, and group 3 (BC3) contained synthesized PMMA microspheres with a size of about 1 μm. The mechanical properties of the three groups were similar, but their curing properties were significantly affected. The presence of CH improved the mechanical and thermal properties. For the BC1 group, the compressive strength increased more than 10 MPa, and the curing temperature decreased 12°. The cement having the optimum properties (BC1) was applied to rats, where it enhanced the bone bonding ability, and bioactivity was observed. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39662.     

Properties and phase segregation of crosslinked PCL‐based polyurethanes

Polyurethane (PU) films were prepared from different types of poly(ε‐caprolactone) glycols and hexamethylene diisocyanate without using any other ingredients such as solvent, catalyst, or chain extender. Polymers were stabilized by crosslinking formed as allophanate and/or biuret linkages during the curing process. The effects of different components on the product properties such as chemical structure, microphase segregation, mechanical strength, thermo‐mechanical, thermal properties, and surface hydrophilicities were investigated by FTIR‐ATR, atomic force microscope, mechanical tester, dynamic mechanical analyses, thermogravimetric analyzer, differential scanning calorimetry, and contact angle measurements. Phase separation of hard and soft segments significantly varied depending on the type and molecular weight of diol and triol. Films containing urethane‐urea bonds displayed the maximum phase separation and the highest mechanical strength. Polyols having higher molecular weight increased hydrophilicity while urea bonds caused a reverse effect resulted by bidentate hydrogen bonds. Results showed PUs with various properties can be synthesized via environmentally friendly process without using any solvent or catalyst. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39758.     

Analysis of ESCO activities using country indicators

Energy Service Companies (ESCOs) are private-sector instruments that offer energy-/emission-improvement (energy saving, energy efficiency, energy conservation and emission reduction) projects, or renewable-energy projects, in the developed and in some developing countries. There has been an increased interest for the provision of such energy services, driven by a restructuring of the gas and electricity sectors, and the push to mainstream sustainable forms of energy into the market. ESCOs are destined to deliver sustainable-energy solutions, especially in emerging markets. Literature reveals that energy/emission improvements of countries may be related to their innovation- and R&D-activity levels. In this work, we use a literature data on the activities and the sectors targeted by ESCOs in 38 countries, summarized in terms of the age of ESCO market (AEM), number of ESCO companies (NE), and total value of ESCO projects (VE). Along with the Global Innovation Index (GII) data of the countries, we investigate the relationships among the ESCO Indicators (EIs: AEM, NE, VE, sectors targeted by ESCOs), and the Country Indicators (CIs: GII and per-capita GDP, energy consumption, CO₂ emission). We observe noteworthy dependencies between the EIs and CIs. Using the simple trend equations we estimate the missing VEs in the original data. We also project, as a hint for the size and orientation of the upcoming Turkish ESCO market, the set of EIs and the distribution of the sectors that are likely to be targeted by ESCOs in Turkey.     

Slider-bearing design with micro-machined wavy-cavity: Parametric Characterization of thermohydrodynamic-operation-scheme

Slider bearings are widely applied in mechanical systems, where the design needs cover increased load capacity, lowered friction and power consumption and creative designs. This work is governed to perform a parametric characterization, by generating a novel structure on the upper slider surface, which can formally be expressed in micro-machined wavy-form, where the individual and combined influences of various structural design parameters and boundary conditions, on the performance records, are also evaluated. Computations put forward that the contribution of the wave amplitude on power loss values is highly dependent on the level of inlet pressure; higher amplitudes are determined to increase power loss in the lowest inlet pressure case of 1.01, whereas the contrary outcome is determined in the higher inlet pressure cases of 3.01 & 5.01. Designing the slider bearing system, based on optimal load capacity, produced the optimum wave number ranges as 10–45, 7–11 and 5–8 for the pad inclinations of 5°, 4° and 3° respectively.