bluuebunny/crossref_metadata_2025 huggingface dataset:
A method for designing flow-through chromatography processes
Authors: Yoshimoto Noriko , Hasegawa Sumiko , Yamamoto Shuichi
Published: February 2019

Continuous manufacturing is expected to increase the productivity of the production of biologics such as protein drugs. However, it is not easy to build the continuous process especially for downstream processing as many unit operations (chromatography and membrane filtration) are involved. An operation method known as flow-through chromatography (FTC) is considered to be an efficient method for separating two components as the flow is continuous. In FTC, a target protein is eluted from the chromatography column without adsorption whereas contaminants are strongly bound. Since at least two different modes of chromatography are needed in order to remove contaminants, two FTC columns have to be connected in order to build the continuous process. This is not an easy task since the mobile phase properties (pH, salt, buffer ions) are different for the two columns. In this paper, we developed a method for designing FTC processes based on the mechanistic models that we have developed for linear gradient elution (LGE) of proteins. The distribution coefficient K as a function of salt concentration, I determined from LGE data were used for the simulation. It was found that the process is quite sensitive to a small change in I. This indicates that FTC processes are carefully monitored and controlled for the stable operation.
Optimization of pectin extraction from the native fruit of Garcinia binucao using response surface methodology
Authors: Robrigado Jed Karl Victor , De Leon Jasen Emil , Orillan Aldous Tyrone , Barajas John Raymond , Gealone Pee Jay
Published: February 2019

Citrus supply for pectin primers in the world market is continually under threat due to the widespread of uncontrolled citrus greening disease outbreaks. As a consequence, a market squeeze in pectin supply was experienced globally and further resulted to a significant surge in prices of pectin derived products. In an attempt to provide an alternative source of pectin primers to the pectin-making industry, we investigate a novel and promising pectin primer native to the Philippines. In this work, we explored extraction of pectin from fruits of the Garcinia binucao tree (GBT). We implement a response surface methodology (RSM) to optimize the extraction of pectin from GBT. Box-behken experimental design was used to obtain the optimal conditions in the extraction process. Temperature (°C), extraction time (min), and pH were found to have significant effects on the pectin yield. Actual values of these independent variables were chosen on the basis of preliminary experimental results. Optimum conditions using ridge analysis were found to be: temperature 72.4°C, extraction time 117.5 min, and pH at 1.68. In conclusion, a high pectin yield obtained from GBT fruits strongly suggests that these fruits are promising alternative primers in pectin production.
Improving the resistance starch of rice through physical and enzymatic process
Authors: Witono Judy Retti , Juliani Janice
Published: February 2019

People with obesity and diabetes mellitus in Indonesia have increased in number from year to year. One of the reasons is caused by high glycemic index (GI) value in rice as our staple food. The GI of the rice ranged from 64 ± 9 to 93 ± 11, where glucose = 100. The objective of this research is to compare several processes in decreasing the GI value of rice, i.e. acid hydrolysis; acid hydrolysis followed by autoclaving-cooling and hydrolysis by pullulanase enzyme. GI values in this study was determined through the percentage of the resistant starch (%RS) as the opposite of GI. The experiment was started by analyzing the viscosity and gelatinization temperature, moisture content, resistant starch, and carbohydrate content of the rice starch. Variations used in this experiment are the type of acid solution (hydrochloric acid, acetic acid, citric acid, and lactic acid), acid concentration (0.01, 0.05, 0.1, 0.15 and 0.2 mole / L), and period of pullulanase hydrolysis (2, 6, and 8 hours). Condition of heating cooling used was 121ºC and 4ºC. The results showed that the highest resistance starch content (7.6%) is obtained from the hydrolysis process using pullulanase enzyme for 8 hours.
Development of noninvasive method of measuring copper and zinc by passive diffusion: an in vitro model
Authors: Landrito Queenie Charisse , Menor Gianina Krisha Rodymae , Sevilla III Fortunato , Tolosa Leah , Tiangco Cristina
Published: February 2019

There has been increasing interest in the determination of essential or toxic elements in human body fluids in relation to health and nutrition. The human body is composed of almost every natural element found in nature. This includes copper and zinc that are both essential if obtained at a right amount and toxic when exceeds. This study aims to develop a noninvasive method for measuring trace amounts of copper and zinc by passive diffusion. A cellulose acetate membrane was used as a model representing human skin. Different amount of permeant concentration of copper and zinc solutions such as 0.1, 0.5, and 1mM were placed inside the membrane and the samples were collected and analyzed using Atomic Absorption Spectroscopy. The amount of copper and zinc diffusing shows proportionality with time. The permeability and steady state flux were computed. Permeability of -2.39×10-7 cm/s and 6.67×10-7 cm/s were computed for copper at 0.1 mM and 0.5 mM concentrations respectively and 3.11×10-7, 4.61×10-7 and 1.75×10-6 cm/s were computed for zinc at 1, 0.5 and 0.1 mM permeant concentrations respectively. For steady state flux, the values computed are 1.22×10-3, 9.03×10-4 and 6.84×10-4 µM/cm2min for zinc at 1, 0.5 and 0.1 mM respectively and -7.84×10-4 and 1.27×10-3 µM/cm2min for copper at 0.5 and 0.1 mM permeant concentrations. The values gathered are all acceptable taking into the account previous studies regarding skin diffusions. This method presents a noninvasive alternative method to track copper and zinc trends.
In-vitro biocompatibility testing of phycobiliproteins fromGracilaria changii
Authors: Rubi Rugi Vicente , Roque Erison , Gutierrez Fritzzie , Hegina May Anne , Martin Jeanell , Mata Arrianne Jaye , Mission Ervin
Published: February 2019

The present study probes into the biocompatibility testing of Phycobiliproteins (PBPs) fromGracilaria changii, in-vitro. The cell survivability and cytotoxicity of PBPs to cultured Human Cervix Carcinoma (Hep-2C) cells were tested and observed using MTT (3-(4, 5- Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) assay. For ten-fold dilutions, Phycobiliproteins (PBPs) promotes highest cell survivability at 10-4 dilution rate with 239.62% and highest cytotoxic effect, with 40.21%, at 10-1 dilution. The compositions of phycobiliproteins were determined using Ultraviolet (UV-Vis) spectrophotometer giving visible absorbance peaks at 498.5, 614 and 651 nm for the three PBPs composition: Phycoerythrin (PE), Phycocyanin (PC) and Allophycocyanin (APC), respectively. The effects of time duration in centrifugation process of Phycobiliproteins (PBPs) fromGracilaria changiiin 3, 5 and 7 minutes, were proven significant on the quantity of the extracted PBPs. The highest average concentration of 20.37 µg/ml for APC, 13.31 µg/ml for PC and 18.57 µg/ml for PE were obtained at the 5 minute-extraction process.
Modeling of metallocene catalyzed propylene polymerization in fluidized bed reactors
Authors: Law Chew-Sang , Hussain Mohd Azlan
Published: February 2019

A study was performed to improve the model for metallocene catalyzed polyolefin polymerization in fluidized bed reactor by adapting multi-scale modeling approach. Monomer concentration and reactor temperature was predicted using kinetic model of polypropylene homopolymerization coupled with well mixed reactor models of fluidized bed reactor. Well mixed model typically used for Ziegler-Nata was selected as supported homogeneous metallocene exhibited heterogeneous property similar to ZN catalyst. Result of simulation showed that model was able to predict reaction temperature accurate with around 3% over-prediction of reactor temperature, which is more accurate than previous model. Model predicted decrease in final monomer concentration from 0.9929 mol/s to 0.986 mol/s when initial reactor was raised from 25C to 75C.
Optimization and analysis for palm oil mill operations via input-output optimization model
Authors: Foong Steve Z. Y. , Andiappan Viknesh , Tan Raymond , Ng Denny K. S.
Published: February 2019

A typical palm oil mill produces crude palm oil, crude palm kernel oil and other biomass from fresh fruit bunches. While the milling process is well established in the industry, insufficient research and development has been done on analyzing the operational performance of a mill. Factors such as operating time and fruit availability affect the performance of a palm oil mill (e.g., capital, operating and labor costs). This paper presents an input-output model to optimize the operations of a palm oil mill based on maximum economic performance. Following this, feasible operating range analysis (FORA) is performed to study the utilization and flexibility of the process. A palm oil mill case study in Malaysia is used to illustrate the proposed approach. Based on the optimized results, it was found that 37% reduction in capital cost and 49% increase in economic performance is achieved. Meanwhile, the utilization index of the mill during peak season increases from 0.48 to 0.76.
Effective process safety management for highly hazardous chemicals
Authors: Sommani Piyanart , Waritswat Lothongkum Anchaleeporn , Jumpasri Panuwat , Hongbin Nichit , Kowhakul Wasana
Published: February 2019

Process safety management (PSM) has been a critical consideration in the plants that handle highly hazardous chemicals (HHCs), flammable gases and liquids. This article introduces PSM standard by OSHA's 29 CFR 1910.119. Further, it highlights an effective PSM for HHCs and provides PSM practices of the industries in Thailand. Effective PSM can prevent or mitigate catastrophic releases of HHCs which can cause health problems, fires, explosions, and fatalities. It is a disciplined framework for managing the integrity of operating systems, safety critical equipment (SCE) and safe work practices. Effective implementation and audits of PSM system and the continual improvement are important. It requires the industries to execute suitable leading and lagging process safety metrics. The inclusive and integrated PSM intents, human factors, good design principles, recognized and generally accepted good engineering practices (RAGAGEPs), engineering and administrative controls, and integrity of operating and maintenance practices are substantial key roles. It is important that the PSM system should be risk-based under the ALARP concept because hazards and risks are not equal, and there are multiple risks and consequences to consider. In summary, the PSM effectiveness depends on, for example, process safety metrics, management review, audit findings and particularly workforce involvement.
Calcium soap from palm fatty acid distillate for ruminant feed: Calcium oxide particles size
Authors: Handojo Lienda , Indarto Antonius , Shofinita Dian , Saadi Muhammad , Yulistia Dea , Hasyyati Fathinah
Published: February 2019

High production of crude palm oil has led Indonesia to become one of the countries that have a large number of palm fatty acid distillate (PFAD) in the world. As a source of fatty acid, PFAD has wide range of uses, including as a fat supplement in the ruminant feed when reacted with a calcium source such as calcium oxide (CaO). At the working temperature above PFAD’s melting point, those reactants form a homogeneous phase with the help of intensive stirring. By the presence of a small amount of water, the mixture will be saponified and become the calcium soap. This research studied how different particles sizes of CaO could influence the reaction conversions based on the acid value of the product. The CaO solid particles were sieved and separated into the different fraction of sizes (<177 μm, 177-320 μm, and 320-640 μm). Smaller particle resulted in a lower acid value which indicates a high conversion of free fatty acid and lower moisture content which is preferable for the product.
A study on the potential of carbon residue from rice husk used as boiler fuel for carbon dioxide capture and wastewater treatment
Authors: Peñaflor Janssen Radley , Carillo Airic James , Estrada Samuel Elijah , Celedonio-Castro Jhulimar
Published: February 2019

Adsorption process both in post carbon dioxide capture and wastewater treatment has been receiving widespread attention over the past decades as a mitigating technology for climate change and water pollution, respectively. With this increasing interest in adsorption processes to address environmental concerns, development of an adsorbent with not just high adsorptive capacity but which is also low cost is of great interest among researchers. In this study, an agricultural waste which was already utilized as a boiler fuel in a paper industry was investigated for its potential as an adsorbent for both carbon dioxide capture and wastewater treatment. Specifically, the CO2 and methylene blue adsorption capacity of carbon residue from rice husk used as boiler fuel was determined and was compared with a biochar synthesized from rice husk. Furthermore, Scanning Electron Microscope (SEM) and Thermogravimetric analysis (TGA) were used for the characterization of the adsorbents. Results showed that the carbon residue can be a potential adsorbent for both applications with about 0.5 wt% CO2 adsorption and 100% removal of the methylene blue.
Composites polyvinyl alcohol filled with nanocellulose from oil palm waste by formic acid hydrolysis
Authors: Aprilia Sri , Razali Nasrullah , Syamsuddin Yanna , Khalil Abdul H.P.S. , Syafrina Dedek
Published: February 2019

Composites polyvinyl alcohol filled with nanocellulose from oil palm empty fruit bunch (OPEFB) and oil palm fronds (OPF) have investigated. Nanocellulose prepared by formic acid 50 wt%. Functional groups and degree of crystalline of nanocellulose were analyzed by FTIR and XRD. The degree of crystalline nanocellulose presented at 2θ at intensity of 22.26 and 21.86 for OPEFB and OPF. Amorphous part of nanocellulose at intensity of 14.68 and 15.86 for OPEFB and OPF. Functional group of nanocellulose give the same pattern for OPEFB and OPF. Nanocellulose reinforce in polyvinyl alcohol as many as 1, 5, 10 and 20% and as a comparison with polyvinyl alcohol without filler. Eight of composite films and one of vinyl alcohol film have studied mechanical properties such as tensile strength and elongation at break, and also functional groups. The tensile strength of OPF 5% and 10% increased than polyvinyl alcohol matrix. Tensile strength OPEFB 10% slightly increase from polyvinyl alcohol. The elongation of composites both OPEFB and OPF decreased with increased of nanocellulose loading.
Production of green nano zero-valent iron (G-nZVI) particles using polyphenol extracts of Tawa-tawa (Euphorbia hirta linn) leaves and green tea (Camelia sinensis) leaves
Authors: Vilando Anabella , Roque Erison , Benitez Maria Aira , Diva Jonathan Rey , Ragindin Jhenea Ellice
Published: February 2019

Green synthesis of nano zero-valent iron (nZVI) can be used for environmental remediation. In this study, nZVI was produced from the extracts of Tawa-tawa (Euphorbia hirta) and Green tea (Camelia sinensis) leaves using Fe2+ and Fe3+ precursors. Solid-liquid extraction was used to obtain the extract of oven-dried Tawa-tawa and Green tea leaves with 60% v/v ethanol at a fixed solid-liquid ratio (1:20) and varying time (30, 60, 90, 120, and 150 min). Total phenolic content (TPC) of the extracts was determined by Follin Ciocalteu method. The extraction time of 60 min yielded the highest average TPC values of 7.26 xx0.01 mg GAE/ g of Tawa-tawa dried sample and 5.23 //0.13 mg GAE/g of Green tea dried sample. To produce 0.1 gram of nZVI, 12 mL and 6 mL tawa-tawa extract were needed for Fe2+ and Fe3+, respectively. For green tea, 24 mL and 20 mL extracts were needed for Fe2+ and Fe3+ to obtain the same amount of particles. G-nZVI has a particle diameter ranging from 50 nm to 130 nm, and mainly composed of iron and oxygen. Synthesized nZVIs from Tawa-tawa and Green tea reduced the nitrates (as nitrogen) concentration from 99.35 mg-L-1 to 42.32 mg-L-1 and 48.77 mg-L-1, respectively.
Analysis of the potential of landfill gas as an alternative for electrical energy source
Authors: Munawar Edi , Emalya Nikita , Hayati Adinda Puspa , Yunardi  , Hakim Lukman
Published: February 2019

Municipal solid waste (MSW) is generated from human activities, where most of them end up at the landfill. The landfill gas produced from the degradation of organic matter in the MSW landfill contains methane can be used as the energy source. Therefore, the objective of this research is to analyze the potential of landfill gas as an alternative for energy source. Two Landfill Simulator Reactor (LSRs) made of high density polyethylene (HDPE) pipe has 50 cm outside diameter and 150 cm of height were operated under natural condition. The first LSR was operated without leachate recirculation (A), while the other one was operated with leachate recirculation (B). Results of this research found the highest methane concentration from LSR A was about 53% and 41.8% from LSR B. This finding was applied to estimate the landfill gas production for electricity generation in Cot Padang Nila landfill. The potential electrical energy that could be produced from Cot Padang Nila landfill is 203 MWh/year if it is operated using LSR A mode, and 161 MWh/year when operated in accordance to LSR B mode. This amounts of energy is suitable to provide electricity for 53-67 households in the vicinity of the landfill.
Copper uptake potential of Philippine giant bamboo (Dendrocalamus asper) under varied initial copper concentration, water hardness and pH
Authors: C.Go Jerwin Lawrence , Madrazo Cynthia F. , Orbecido Aileen H. , de Castro Ma. Ellenita G. , Belo Lawrence P.
Published: February 2019

Copper is a commonly used metal in construction, engineering, agriculture and water treatment. Consequently, increased copper concentrations resulting in adverse environmental effects is inevitable. Phytoremediation using Dendrocalamus asper or Philippine giant bamboo (PGB) is a viable option for treatment of copper-contaminated media, but their copper uptake potential remains largely unexplored. As such, the copper uptake of PGB was evaluated under varying environmental conditions, namely initial copper concentration, water hardness and pH.Six-month old propagules were planted in artificially contaminated water in order to determine the copper uptake after 16 days of treatment. Using a Box-Behnken design of experiment, it was found that both initial copper concentration and pH have significant and proportional effects on copper uptake. However, due to possible speciation and/or competition, the optimum copper uptake occurred at 20 ppm Cu and pH 5 (as opposed to 7). A mathematical equation, bearing an R2 = 0.7097, was constructed as a possible model for copper uptake of PGB to understand when PGB phytoremediation is most effective. At copper concentrations lower than 3.81 ppm, higher pH is beneficial to copper uptake and vice versa. Overall, phytoremediation using D. asper or PGB is effective especially at low pH and elevated copper concentrations.
Techno-economic analysis of a combined cooling, heating and power system based on hot sedimentary aquifer for hotel building in tropical countries
Authors: Prasetio Heru , Euodia Kezia Dara , Purwanto Widodo Wahyu
Published: February 2019

Low enthalpy geothermal based Combined Cooling, Heating and Power (CCHP) system for building is expected can increase energy efficiency and reduce carbon dioxide emission. The aim of this study is to assess techno-economic performances of a CCHP for hotel building in tropical countries with total energy demand of 7.64 MW. The fresh geothermal fluid was divided by 15% to power generation system of Organic Rankine Cycle (ORC) and the waste heat merged with the rest fresh geothermal to absorption refrigeration system and heating systems. Cycle Tempo and COMSOL are used to simulate CCHP system and a borehole of hot sedimentary aquifer (HSA), respectively. The simulation results indicate that total CCHP system efficiency is 36.61% consist of ORC efficiency and absorption cycle efficiency are 12.77% and 57.88%, respectively with emission reduction of 1.4 ton CO2 eq. per year compare to conventional grid electricity. The best business scheme was BOO with financial incentives, which were tax allowance, soft loan, and grant. Therefore, the production prices were 0.08 USD/kWth, 0.10 USD/kWeh, and 12.03 USD/MMBtu for cooling, electricity, and heating respectively.
Development of optical detection for antibiotic residues: oxytetracycline in freshwater aquaculture
Authors: Marquez Merryl Jean , Roncales Ciara Jane , Tigcal Roma Ayanah , Quinto Edna
Published: February 2019

This study satisfies the primary need for a simple monitoring scheme for antibiotic residue content in freshwater systems to regulate and prevent immunization of aquaculture species to antibiotics. A series of antibiotic solutions with decreasing concentrations (from 5ppm to 1ppm) were prepared, with each solution containing fixed amounts of the reagents (p-Chloranilic acid in acetonitrile solution, and pure acetonitrile) and a buffer solution to distinctly simulate the environmental conditions of actual freshwater systems. Using the UV-Vis Spectrophotometer with the optimum wavelength of 519nm, the stability, repeatability, and sensitivity tests were performed, where relative standard deviation (RSD) values of less than 10% were obtained. The limit of detection was also calculated to be 0.54ppm, using the RSD result from the sensitivity test. Actual freshwater sample was gathered and subjected to a repeatability test using the same working wavelength. Results showed that the trend in the absorbance reading for the real water sample differed with the laboratory standard samples. This shift may have been caused by other interfering chemicals used in aquaculture that were present in the sample. Modified detection method of Oxytetracycline (OTC) in freshwater was made to provide solution to the main objective.
Formation of surface protective coatings on arsenopyrite using Al-catecholate complex and its mode of inhibition of arsenopyrite oxidation
Authors: Park Ilhwan , Tabelin Carlito , Inano Hiroyuki , Seno Kensuke , Higuchi Kazuki , Ito Mayumi , Hiroyoshi Naoki
Published: February 2019

Arsenopyrite is the most common arsenic-bearing sulfide mineral in nature. It is readily oxidized and releases toxic arsenic (As) into the environment when exposed to atmospheric conditions via anthropogenic activities like mining, mineral processing, extractive metallurgy, and underground space developments. Carrier-microencapsulation (CME) is a technique that uses metal(loid)-organic complexes to selectively form protective coatings on the surfaces of sulfide minerals. In this study, CME using Al-catecholate complexes (i.e., Al-based CME) was investigated to suppress the oxidation of arsenopyrite. Aluminum(III) and catechol form three complex species depending on the pH and among them, [Al(cat)]+ was the most effective in suppressing arsenopyrite oxidation. Its suppressive effect was improved as [Al(cat)]+ concentration increased due most likely to the formation of a more extensive surface protective coating at higher concentrations. Surface characterization of leaching residues using SEM-EDX and XPS indicates that CME-treated arsenopyrite was covered with bayerite (γ-Al(OH)3). The results of electrochemical studies showed that the surface protective coatings suppressed both anodic and cathodic half-cell reactions of arsenopyrite oxidation.
Production of hydrogen gas from biomass oil palm empty fruit bunch using electrolysis method
Authors: Amri Resti Yunia , Saba Annisa Khafiya , Asfarina Asrina , Putra Rudy Syah
Published: February 2019

Biomass oil palm empty fruit bunch (OPEFB) is a sustainable source for hydrogen production. OPEFB and FeCl3.6H2O oxidizers (0.1, 0.2, 0.3 and 0.4 mol) were refluxed at 90-98 ° C for 5 hours. The acquired aliquot was used to produce H2 with variation of storage time (fresh aliquot and old aliquot). The production of H2 was carried out by electrolysis method where the aliquot was diluted by ratio of 1:10. The electrolysis was carried out using two electrodes as anode (titanium) and cathode (stainless steel) with DC current voltage 15 V. The principle of gas mass transfer in the vessel following Bernoulli's principle was used to calculate the volume of H2 formed. The change of current by formation of H2 were used to calculate the volume of H2 following Faraday’s law. The results showed that the storage time of the solution affects the production time of H2. The oxidizer concentration has no effect on the H2 production in the fresh solution but has effect on the old solution. The best solution to produce H2 is a 0.1 mol oxidizer solution with a production time of 8 minutes. The produced H2 can be used in power generation by a fuel cell process.
Gasification of rice hulls into methane by rumen fluid: A simulation study
Authors: Barajas John Raymond , Lucero Arpon
Published: February 2019

Methane gas, the third widely-used source of energy, has been identified as a potential alternative to climate-change causing fuels. Due to increased climate change awareness, recent trends in researches have shifted their focus on optimizing production rates of methane gas. This study contributes to research by investigating the degree of conversion of rice hulls into methane using rumen fluid. We first identify the kinetic parameters defining therate of hydrolyzing rice hulls into glucose by implementing a semi-factorial experimental design. We then simulated methane production in four different reactor configurations. Historical data were extracted from different literatures and these were subsequently used in the simulation study. Simulation results showed that the continuous stirred tank reactor (CSTR) gave the shortest reaction time and highest methane yield which ranged from 7.1 9.5 mol/L and 3 4 days, respectively. In conclusion, this study provides an alternative approach to the conduct of understanding the optimal conditions necessary to achieve maximal methane gas production.
Heterogeneous catalytic reaction of glycerol with acetone for solketal production
Authors: Sulistyo Hary , Hapsari Indri , Budhijanto  , Sediawan Wahyudi Budi , Rahayu Suprihastuti Sri , Azis Muhammad Mufti
Published: February 2019

The rapid growth of biodiesel industries has also increased the production of glycerol as side product. Without proper treatment, glycerol may cause serious problem for the environment. Glycerol can be reacted with acetone to produce solketal as a fuel additive. The aim of this research was to study the glycerol ketalization with acetone using Amberlyst-15 as catalyst. Experiments were undertaken in a batch reactor. A set of experiment was conducted at varying temperature (35 to 60oC), initial mole ratio of acetone to glycerol (2 – 6) and catalyst loading (1,3,5 and 7% w/w). Sample was analyzed every 30 minutes. The results showed that optimal condition was achieved at temperature of 60 °C, initial mole ratio of acetone to glycerol of 3, and the catalyst load of 3%. The highest glycerol conversion achieved was 87.41 % at 60oC for 3 hours reaction. The Pseudo Steady State Hypothesis (PSSH) has been developed as rnet =k4.CG.CAC/1+k5.CG. Parameter estimation of k4 and k5 were evaluated from experimental data at various temperatures. It appears that the model predicted the experimental data well at high conversion (above 80 min) and showed relatively poor prediction below 80 min.
La tomographie de l’atmosphère au service de l’astrophysique
Authors: Neichel Benoit , Rousset Gérard
Published: February 2019

Depuis près de 30 ans, l’optique adaptative (OA) se développe en astronomie pour corriger les effets de la turbulence atmosphérique et recouvrer la limite de diffraction des grands télescopes au sol. Récemment, les OAs grand champ avec étoiles laser s’appuyant sur la tomographie de l’atmosphère ont été démontrées dans plusieurs observatoires pour offrir une correction dans un champ de vue accru et une bonne couverture du ciel. Ces techniques sont aujourd’hui étendues pour satisfaire les besoins des extrêmement grands télescopes qui verront le jour au milieu des années 2020.
Maritime Herausforderungen der Zukunft
Authors: Meißner Dana
Published: February 2019

Unsere Welt erlebt massive soziale, technologische und klimatische Veränderungen. Die Weltbevölkerung wächst weiter, landgestützte Rohstoffe, Nahrungsmittel und Wohnraum werden immer knapper. Die Zukunft der Menschheit wird sich immer mehr an und auf den Meeren abspielen. Mehr Menschen werden auf See leben und arbeiten sowie Energie, Nahrung und Rohstoffe direkt aus dem Meer produzieren und konsumieren.
Künstliche Intelligenz und Maschinelles
Lernen
Authors: Hahn Peter
Published: February 2019

Maschinelles Lernen (ML), ein Teilbereich der Künstlichen Intelligenz, ist die
Fähigkeit von Computer-Algorithmen, Wissen aus Beispielen zu lernen, ohne dafür
explizit programmiert zu sein und dieses Wissen dann auf unbekannte Fälle
anzuwenden. Die Anwendung von ML in der Medizin wird in den nächsten Jahren
exponentiell zunehmen. Ärzte sollten daher über die prinzipiellen Arten von ML
sowie den Prozess des ML grundlegende Kenntnisse haben. Denn nur so ist es
möglich, ML optimal zu nutzen und die Grenzen und Probleme des Verfahrens zu
erkennen.
A high resolution extreme ultraviolet spectrometer system optimized for harmonic spectroscopy and XUV beam analysis
Authors: Wünsche Martin , Fuchs Silvio , Weber Thomas , Nathanael Jan , Abel Johann J. , Reinhard Julius , Wiesner Felix , Hübner Uwe , Skruszewicz Slawomir J. , Paulus Gerhard G. , Rödel Christian
Published: February 2019

We present a modular extreme ultraviolet (XUV) spectrometer system optimized for a broad spectral range of 12–41 nm (30–99 eV) with a high spectral resolution of λ/Δλ ≳ 784 ± 89. The spectrometer system has several operation modes for (1) XUV beam inspection, (2) angular spectral analysis, and (3) imaging spectroscopy. These options allow for a versatile use in high harmonic spectroscopy and XUV beam analysis. The high performance of the spectrometer is demonstrated using a novel cross-sectional imaging method called XUV coherence tomography.
Characterization of the HAYSTAC axion dark matter search cavity using microwave measurement and simulation techniques
Authors: Rapidis Nicholas M. , Lewis Samantha M. , van Bibber Karl A.
Published: February 2019

Many searches for axion cold dark matter rely on the use of tunable electromagnetic resonators. Current detectors operate at or near microwave frequencies and use cylindrical cavities with cylindrical tuning rods. The cavity performance strongly impacts the signal power of the detector, which is expected to be very small even under optimal conditions. There is strong motivation to characterize these microwave cavities and improve their performance in order to maximize the achievable signal power. We present the results of a study characterizing the HAYSTAC (Haloscope At Yale Sensitive to Axion Cold dark matter) cavity using bead perturbation measurements and detailed 3D electromagnetic simulations. This is the first use of bead perturbation methods to characterize an axion haloscope cavity. In this study, we measured impacts of misalignments on the order of 0.001 in. and demonstrated that the same impacts can be predicted using electromagnetic simulations. We also performed a detailed study of mode crossings and hybridization between the TM010 mode used in operation and other cavity modes. This mixing limits the tuning range of the cavity that can be used during an axion search. By characterizing each mode crossing in detail, we show that some mode crossings are benign and are potentially still useful for data collection. The level of observed agreement between measurements and simulations demonstrates that finite element modeling can capture non-ideal cavity behavior and the impacts of very small imperfections. 3D electromagnetic simulations and bead perturbation measurements are standard tools in the microwave engineering community, but they have been underutilized in an axion cavity design. This work demonstrates their potential to improve understanding of existing cavities and to optimize future designs.
Thickness of accumulation layer in amorphous indium-gallium-zinc-oxide thin-film transistors by Kelvin Probe Force Microscopy
Authors: Shi Xuewen , Lu Congyan , Xu Guangwei , Yang Guanhua , Lu Nianduan , Ji Zhuoyu , Geng Di , Li Ling , Liu Ming
Published: February 2019

In this letter, we measured the thickness of an accumulation layer (dacc) in amorphous Indium-Gallium-Zinc-Oxide thin-film transistors (TFTs) using Kelvin Probe Force Microscopy (KPFM). By scanning the active layer surface from the interface to the back channel, we obtained potential from different thickness profiles, which show the variation of the carrier concentration. It was found that potential followed an exponential decay function from the interface to the back channel. Furthermore, there was a transition point after which the potential changed little. From this potential map, the thickness of the accumulation layer could be considered as the height difference between the transition point and the interface. Meanwhile, by controlling gate voltage (VG) during the KPFM scanning process, we obtained a relationship between dacc and VG. The results indicated that when VG was smaller than threshold voltage (Vth), dacc increased drastically with the increase in VG; after that, dacc was almost independent of VG, indicating that dacc reached a saturation value around 15 nm. This finding gave us a clear physical image about charge distribution in TFT and facilitated the understanding of device physics.
Pseudo-resonance and energy band gaps in plasmonic crystals
Authors: Akbari-Moghanjoughi M.
Published: February 2019

In this paper, using the generalized coupled pseudoforce model with driving elements, we develop a method to study the plasmon excitations and energy band structure in a plasmonic crystal. It is shown that the presence of the periodic ion core potential leads to a pseudo-resonance condition in the plasmon wavefunction and electrostatic potential profiles, quite analogous to the frequency resonance, leading to the gap formation in the energy dispersion profiles. It is found that the dual length scale character of plasmon excitations leads to the occurrence of a critical value of ac = 2πλp for the lattice constant (λp being the plasmon wavelength) above and below which the energy band structure of plasmonic crystals becomes substantially different. It is also found that energy bandgap positions of the parabolic free electron energy dispersion relation are slightly higher compared to those of the plasmon excitations. The wavefunction and electrostatic potential solution for a one dimensional plasmonic lattice with a generalized periodic potential are also derived in this research. Current development helps us to illuminate the basic properties of the collective quantum phenomenon in many physical contexts by appropriately incorporating the collective effect in the root level and can have a wide range of applications in developments of the rapidly growing fields of nano-technology, nano-electronics, and plasmonics.
Synchronized generation and coalescence of largely dissimilar microdroplets governed by pulsating continuous-phase flow
Authors: Zhang Y. Y. , Xia H. M. , Wu J. W. , Zhang J. , Wang Z. P.
Published: February 2019

The effects of pulsating continuous-phase flow on droplet generation at a T-junction are investigated. The pulsating perturbation produced by a microfluidic oscillator is found to govern the droplet formation. In this way, the droplet size, the generation frequency, and the fluid properties become uncorrelated. Within a wide viscosity (1–60 cP) and flow rate range [Qd,max/Qd,min is on the order of O(102)] of the discrete fluid, the droplet volume increases linearly with Qd and hence can be easily tuned. Using a single perturbation source, microdroplets of largely different viscosities and volumes can be synchronously generated, facilitating subsequent precise control and manipulations such as one-to-one coalescence.
Characterization of a high-brightness, laser-cooled Li+ ion source
Authors: Gardner J. R. , McGehee W. R. , McClelland J. J.
Published: February 2019

Ion sources based on laser cooling have recently provided new pathways to high-resolution microscopy, ion milling, and ion implantation. Here, we present the design and detailed characterization of a 7Li magneto-optical trap ion source (MOTIS) with a peak brightness of (1.2 ± 0.2) × 105 A m−2 sr−1 eV−1 and a maximum continuous current over 1 nA. These values significantly surpass previous Li MOTIS performance benchmarks. Using simple models, we discuss how the performance of this system relates to fundamental operating limits. This source will support a range of projects using lithium ion beams for surface microscopy and nanostructure characterization, including Li+ implantation for studies of ionic transport in energy storage materials.
Near-field and far-field optical properties of magnetic plasmonic core-shell nanoparticles with non-spherical shapes: A discrete dipole approximation study
Authors: Bhardwaj Shweta , Barr Jim , Chaffin Elise , Huang Xiaohua , Wang Yongmei
Published: February 2019

The combined optical and magnetic properties of magnetic-plasmonic core-shell nanoparticles (NPs) makes them ideal candidates for many applications in biomedical fields. Plasmonic properties of the shell gives rise to Surface Enhanced Raman Scattering (SERS) that can be utilized for sensitive detections, while magnetic properties are useful for magnetic separation and magnetic guided delivery. The plasmonic properties of the shell depends on both the size and shape of the core and shell, and this property, in principle, can be calculated using the Discrete Dipole Approximation (DDA) method. However, since the DDA is an approximation method, its accuracy to calculate the plasmonic properties of the shell, especially the near-field enhancement relevant to SERS, has not been examined carefully. We present a systematic test on the accuracy of the DDA to calculate the plasmonic properties in terms of both the extinction spectra and the near-field enhancement of the magnetic-plasmonic core-shell NPs. Accuracy of the DDA method was first investigated in comparison to Mie theory results for spherical core-shell NPs, since Mie theory gives the exact solution to spherical shaped particles. DDA calculations were further extended to core-shell nanoparticles with octahedral cores. We elucidate convergence of the DDA results by considering the effects of dipole distance and shell thickness in regard to the NP spectral properties. This work validates application of the DDA methods for calculating electrodynamic properties of core-shell NPs and highlights plasmonic properties of core-shell with non-spherical cores.
Abrupt regime shifts in post-fire resilience of Mediterranean mountain pinewoods are fuelled by land use
Authors: Camarero J. Julio , Sangüesa-Barreda Gabriel , Pérez-Díaz Sebastián , Montiel-Molina Cristina , Seijo Francisco , López-Sáez José Antonio
Published: February 2019

Post-fire forest resilience must be quantified in a long-term perspective considering changes in land-use related to fire dynamics. Historical land-use changes leading to increased wildfire severity may produce no analogue regime shifts including a loss in post-fire growth recovery. Here we reconstruct the historical fire dynamics by combining paleoecological proxies, historical fire records and tree-ring width data of relict Pinus nigra subsp. salzmannii forests in the Sierra de Gredos (central Spain). A high incidence of historical fires was recorded in the 1890s, coinciding with a peak in charcoal accumulation rates and a sharp decrease in pollen of P. nigra/Pinus sylvestris with a rapid increase of pollen of more flammable Pinus pinaster and shrubs. The shift observed in pollen assemblages, coupled with a peak in charcoal influx, support the occurrence of high-severity fires during the 1890s, when abrupt growth suppressions were observed. Trees took 2 years to recover to their pre-fire growth rates. Lasting growth-recovery periods or no growth suppression were observed in the 1920s and 1980s, when fire frequency was also high but the study sites were fragmented or protected. We documented an abrupt regime shift in the fire record during the 1890s affecting pine forests, which rapidly recovered pre-fire growth rates.
Thermal biology of the spotted snow skink, Niveoscincus ocellatus, along an altitudinal gradient
Authors: Yuni Luh P. E. K. , Jones Susan M. , Wapstra Erik
Published: February 2019

Body temperatures in ectotherms are strongly affected by their thermal environment. Ectotherms respond to variation in the thermal environment either by modification of behavioural thermoregulation to maintain their optimal body temperature or by shifting their optimal body temperature. In this study, the body temperatures of males of three populations of spotted snow skinks, Niveoscincus ocellatus, living along an altitudinal gradient (low, mid, and high altitude) were studied in the field and laboratory in spring, summer, and autumn, representing the full activity period of this species. The environmental variation across both sites and seasons affected their field active body temperatures. At the low and mid altitude, N. ocellatus had a higher mean body temperature than at the high altitude. Animals achieved their thermal preference at the low and mid altitude sites in all seasons. At the high altitude, however, N. ocellatus struggled to reach its preferred body temperatures, especially in autumn. The lower body temperature at the high-altitude site is likely due to limited thermal opportunity and/or an effect of avoiding the costs associated with increased intensity of basking.
Priming of microglia with IFN-γ slows neuronal gamma oscillations in situ
Authors: Ta Thuy-Truc , Dikmen Hasan Onur , Schilling Simone , Chausse Bruno , Lewen Andrea , Hollnagel Jan-Oliver , Kann Oliver
Published: February 2019

Significance

Priming with classic lymphocyte cytokine, interferon-gamma (IFN-γ) is crucial during the complex activation process of tissue macrophages, such as microglia in the CNS, under pathological conditions. According to current biological concepts, priming permits an exaggerated macrophage immune response given a secondary inflammatory stimulus like bacterial components occurs. Here, we demonstrate that priming with IFN-γ itself induces proliferation and moderate activation of microglia, including up-regulation of inducible nitric oxide synthase (iNOS). Importantly, the concomitant moderate release of nitric oxide (NO) is sufficient to disturb fast neuronal network oscillations (30–70 Hz) that underlie higher brain functions, such as perception, attention, and memory. This mechanism might contribute to early cognitive impairment in chronic brain disorders, such as multiple sclerosis and Alzheimer’s disease.
School English, literature and the knowledge‐base question
Authors: Yates Lyn , Davies Larissa McLean , Buzacott Lucy , Doecke Brenton , Mead Philip , Sawyer Wayne
Published: February 2019

This article takes up questions about knowledge and the school curriculum with respect to literary studies within subject English. Its intention is to focus on literary studies in English from the context of current waves of curriculum reform, rather than as part of the conversations primarily within the field of English, to raise questions about the knowledge agenda, and the knowledge‐base agenda for teaching and teacher education. The selection of texts and form of study of literature within the English curriculum has long been an area of controversy. Without assuming a particular position on knowledge in this area, this article shows that important questions of what knowledge‐base teachers are expected to bring to their work are elided both in current regulations and debates, and in research on ‘good teaching’ in this area. If ‘literary studies’ (as a discipline or university major) is itself an unstable and changing field, what kind of knowledge does a good English teacher bring to their work? This paper takes up these questions in the context of the Australian Curriculum and standards for teacher registration, but it also points to the way these issues about knowledge are of broader relevance for researchers and teacher education.
Die another way: Ferroptosis drives tuberculosis pathology
Authors: Meunier Etienne , Neyrolles Olivier
Published: February 2019

In this issue of JEM, Amaral et al. (https://doi.org/10.1084/jem.20181776) provide the first evidence that ferroptosis, a newly described form of regulated cell death, is detrimental for the host during a Mycobacterium tuberculosis infection. This finding has important implications for the development of host-directed therapies for tuberculosis.
Plumbing constructions and the domain of outer communication for 5-dimensional stationary black holes
Authors: Khuri Marcus , Matsumoto Yukio , Weinstein Gilbert , Yamada Sumio
Published: February 2019

The topology of the domain of outer communication for 5-dimensional stationary bi-axisymmetric black holes is classified in terms of disc bundles over the 2-sphere and plumbing constructions. In particular we find an algorithmic bijective correspondence between the plumbing of disc bundles and the rod structure formalism for such spacetimes. Furthermore, we describe a canonical fill-in for the black hole region and cap for the asymptotic region. The resulting compactified domain of outer communication is then shown to be homeomorphic toS4S^4, a connected sum ofS2×S2S^2\times S^2’s, or a connected sum of complex projective planesCP2\mathbb {CP}^2. Combined with recent existence results, it is shown that all such topological types are realized by vacuum solutions. In addition, our methods treat all possible types of asymptotic ends, including spacetimes which are asymptotically flat, asymptotically Kaluza-Klein, or asymptotically locally Euclidean.
Cellular crowding influences extrusion and proliferation to facilitate epithelial tissue repair
Authors: Franco Jovany J. , Atieh Youmna , Bryan Chase D. , Kwan Kristen M. , Eisenhoffer George T.
Published: February 2019

Epithelial wound healing requires a complex orchestration of cellular rearrangements and movements to restore tissue architecture and function after injury. While it is well known that mechanical forces can affect tissue morphogenesis and patterning, how the biophysical cues generated after injury influence cellular behaviors during tissue repair is not well understood. Using time-lapse confocal imaging of epithelial tissues in living zebrafish larvae, we provide evidence that localized increases in cellular crowding during wound closure promote the extrusion of nonapoptotic cells via mechanically regulated stretch-activated ion channels (SACs). Directed cell migration toward the injury site promoted rapid changes in cell number and generated shifts in tension at cellular interfaces over long spatial distances. Perturbation of SAC activity resulted in failed extrusion and increased proliferation in crowded areas of the tissue. Together, we conclude that localized cell number plays a key role in dictating cellular behaviors that facilitate wound closure and tissue repair.