bluuebunny/crossref_metadata_2025 huggingface dataset:
Top-Down Approaches Towards Single Crystal Perovskite Solar Cells
Authors: Schlipf Johannes , Askar Abdelrahman M. , Pantle Florian , Wiltshire Benjamin D. , Sura Anton , Schneider Peter , Huber Linus , Shankar Karthik , Müller-Buschbaum Peter
Published: March 2018

Solar cells employing hybrid perovskites have proven to be a serious contender versus established thin-film photovoltaic technologies. Typically, current photovoltaic devices are built up layer by layer from a transparent substrate (bottom-up approach), while the deposition of the perovskite layer itself comes with many challenges including the control of crystal size, nucleation density and growth rate. On the other hand, single crystals have been used with great success for studying the fundamental properties of this new class of optoelectronic materials. However, optoelectronic devices fabricated from single crystals often employ different materials than in their thin film counterparts. Here, we demonstrate various top-down approaches for low-temperature processed organic-inorganic metal halide perovskite single crystal devices. Our approach uses common and well-established material combinations that are often used in polycrystalline thin film devices. The use of a polymer bezel allows easier processing of small crystals and the fabrication of solution-processed, free-standing perovskite single crystal devices. All in all these approaches can supplement other measurements of more fundamental material properties often requiring perovskite single crystals by rendering a photovoltaic characterization possible on the very same crystal with comparable material combinations as in thin film devices.
Hydrothermal Synthesis of Cr2Se3 Hexagons for Sensitive and Low-level Detection of 4-Nitrophenol in Water
Authors: Ramaraj Sukanya , Mani Sakthivel , Chen Shen-Ming , Palanisamy Selvakumar , Velusamy Vijayalakshmi , Hall James M. , Chen Tse-Wei , Tseng Tien-Wen
Published: March 2018

We report a simple hydrothermal method used for the synthesis of Cr2Se3hexagons (h-Cr2Se3) and its application towards electrochemical sensing of 4-nitrophenol (4-NP). The formation of h-Cr2Se3was confirmed by using scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The electrochemical activity of the h-Cr2Se3modified screen-printed carbon electrode (SPCE) towards 4-NP was studied using cyclic voltammetry (CV) and amperometric i-t techniques. Typically, the obtained results were compared with those for a bare SPCE. The CV result clearly reveals that h-Cr2Se3modified SPCE has higher catalytic activity towards reduction of 4-NP than bare SPCE. Hence, h-Cr2Se3modified SPCE was concluded as a viable sensor for sensitive determination of 4-NP. Under optimized conditions, h-Cr2Se3modified SPCE demonstrates the excellent capacity to detect the 4-NP in a linear range from 0.05 µM to 908.0 µM. The LOD and sensitivity in detection of 4-NP were determined at 0.01 µM and 1.24 µAµM−1cm−2respectively. The sensor is highly selective and stable and shows reproducible recovery of 4-NP in domestic supply and river water samples.
Variation in diagnostic test requests and outcomes: a preliminary metric for OpenPathology.net
Authors: O’Sullivan Jack W. , Heneghan Carl , Perera Rafael , Oke Jason , Aronson Jeffrey K. , Shine Brian , Goldacre Ben
Published: March 2018

Efforts to reduce healthcare costs have led to the development of metrics to identify unwarranted variation in care. Previous work assessing diagnostic tests is limited, despite their substantial contribution to expenditure. We explored C-reactive Protein (CRP) and Erythrocyte Sedimentation Rate (ESR) tests ordered across Oxfordshire NHS General Practices, and the proportion of tests that yielded an abnormal result, and identified practices that had a proportion of abnormal CRP and ESR results 3 standard deviations below the mean. We estimated the adjusted average proportion of abnormal CRP and ESR tests that yielded abnormal results from each practice, after adjusting for differences in practice populations. These proportions were plotted against the total CRP and ESR requests per practice. We constructed funnel plots to identify practices 3 standard deviations below the mean proportion of abnormal CRP and ESR tests. We analysed 143,745 CRP and 30,758 ESR requests from 69 practices. Twelve (17%) and 7 (10%) practices were more than 3 standard deviations below the mean for CRP and ESR testing respectively. Two practices (3%) were below the 99.8% limit for both CRP and ESR ordering. Variation in the proportion of tests with an abnormal result shows promise for auditing variation in care.
Groundwater oxygen isotope anomaly before the M6.6 Tottori earthquake in Southwest Japan
Authors: Onda Satoki , Sano Yuji , Takahata Naoto , Kagoshima Takanori , Miyajima Toshihiro , Shibata Tomo , Pinti Daniele L. , Lan Tefang , Kim Nak Kyu , Kusakabe Minoru , Nishio Yoshiro
Published: March 2018

Geochemical monitoring of groundwater in seismically-active regions has been carried out since 1970s. Precursors were well documented, but often criticized for anecdotal or fragmentary signals, and for lacking a clear physico-chemical explanation for these anomalies. Here we report – as potential seismic precursor – oxygen isotopic ratio anomalies of +0.24‰ relative to the local background measured in groundwater, a few months before the Tottori earthquake (M 6.6) in Southwest Japan. Samples were deep groundwater located 5 km west of the epicenter, packed in bottles and distributed as drinking water between September 2015 and July 2017, a time frame which covers the pre- and post-event. Small but substantial increase of 0.07‰ was observed soon after the earthquake. Laboratory crushing experiments of aquifer rock aimed to simulating rock deformation under strain and tensile stresses were carried out. Measured helium degassing from the rock and 18O-shift suggest that the co-seismic oxygen anomalies are directly related to volumetric strain changes. The findings provide a plausible physico-chemical basis to explain geochemical anomalies in water and may be useful in future earthquake prediction research.
Potential applications of Pseudomonas sp. (strain CPSB21) to ameliorate Cr6+ stress and phytoremediation of tannery effluent contaminated agricultural soils
Authors: Gupta Pratishtha , Rani Rupa , Chandra Avantika , Kumar Vipin
Published: March 2018

Contamination of agricultural soil with heavy metals has become a serious concern worldwide. In the present study, Cr6+ resistant plant growth promoting Pseudomonas sp. (strain CPSB21) was isolated from the tannery effluent contaminated agricultural soils and evaluated for the plant growth promoting activities, oxidative stress tolerance, and Cr6+ bioremediation. Assessment of different plant growth promotion traits, such as phosphate solubilization, indole-3-acetic acid production, siderophores, ammonia and hydrogen cyanide production, revealed that the strain CPSB21 served as an efficient plant growth promoter under laboratory conditions. A pot experiment was performed using sunflower (Helianthus annuus L.) and tomato (Solanum lycopersicum L.) as a test crop. Cr6+ toxicity reduced plant growth, pigment content, N and P uptake, and Fe accumulation. However, inoculation of strain CPSB21 alleviated the Cr6+ toxicity and enhanced the plant growth parameters and nutrient uptake. Moreover, Cr toxicity had varied response on oxidative stress tolerance at graded Cr6+ concentration on both plants. An increase in superoxide dismutase (SOD) and catalase (CAT) activity and reduction in malonialdehyde (MDA) was observed on inoculation of strain CPSB21. Additionally, inoculation of CPSB21 enhanced the uptake of Cr6+ in sunflower plant, while no substantial enhancement was observed on inoculation in tomato plant.
Human cytochrome P450 2B6 genetic variability in Botswana: a case of haplotype diversity and convergent phenotypes
Authors: Tawe Leabaneng , Motshoge Thato , Ramatlho Pleasure , Mutukwa Naledi , Muthoga Charles Waithaka , Dongho Ghyslaine Bruna Djeunang , Martinelli Axel , Peloewetse Elias , Russo Gianluca , Quaye Isaac Kweku , Paganotti Giacomo Maria
Published: March 2018

Identification of inter-individual variability for drug metabolism through cytochrome P450 2B6 (CYP2B6) enzyme is important for understanding the differences in clinical responses to malaria and HIV. This study evaluates the distribution ofCYP2B6alleles, haplotypes and inferred metabolic phenotypes among subjects with different ethnicity in Botswana. A total of 570 subjects were analyzed forCYP2B6polymorphisms at position 516 G > T (rs3745274), 785 A > G (rs2279343) and 983 T > C (rs28399499). Samples were collected in three districts of Botswana where the population belongs to Bantu (Serowe/Palapye and Chobe) and San-related (Ghanzi) ethnicity. The three districts showed different haplotype composition according to the ethnic background but similar metabolic inferred phenotypes, with 59.12%, 34.56%, 2.10% and 4.21% of the subjects having, respectively, an extensive, intermediate, slow and rapid metabolic profile. The results hint at the possibility of a convergent adaptation of detoxifying metabolic phenotypes despite a different haplotype structure due to the different genetic background. The main implication is that, while there is substantial homogeneity of metabolic inferred phenotypes among the country, the response to drugs metabolized via CYP2B6 could be individually associated to an increased risk of treatment failure and toxicity. These are important facts since Botswana is facing malaria elimination and a very high HIV prevalence.
Genome-wide somatic variant calling using localized colored de Bruijn graphs
Authors: Narzisi Giuseppe , Corvelo André , Arora Kanika , Bergmann Ewa A. , Shah Minita , Musunuri Rajeeva , Emde Anne-Katrin , Robine Nicolas , Vacic Vladimir , Zody Michael C.
Published: March 2018

Reliable detection of somatic variations is of critical importance in cancer research. Here we present Lancet, an accurate and sensitive somatic variant caller, which detects SNVs and indels by jointly analyzing reads from tumor and matched normal samples using colored de Bruijn graphs. We demonstrate, through extensive experimental comparison on synthetic and real whole-genome sequencing datasets, that Lancet has better accuracy, especially for indel detection, than widely used somatic callers, such as MuTect, MuTect2, LoFreq, Strelka, and Strelka2. Lancet features a reliable variant scoring system, which is essential for variant prioritization, and detects low-frequency mutations without sacrificing the sensitivity to call longer insertions and deletions empowered by the local-assembly engine. In addition to genome-wide analysis, Lancet allows inspection of somatic variants in graph space, which augments the traditional read alignment visualization to help confirm a variant of interest. Lancet is available as an open-source program at https://github.com/nygenome/lancet.
Nickel(ii) pincer complexes demonstrate that the remote substituent controls catalytic carbon dioxide reduction
Authors: Burks Dalton B. , Davis Shakeyia , Lamb Robert W. , Liu Xuan , Rodrigues Roberta R. , Liyanage Nalaka P. , Sun Yujie , Webster Charles Edwin , Delcamp Jared H. , Papish Elizabeth T.
Published: March 2018

New pincers containing a pyridinol ring form active nickel catalysts for CO2 reduction, and interestingly protonation switches the catalyst off.
Arylsilylation of aryl halides using the magnetically recyclable bimetallic Pd–Pt–Fe3O4 catalyst
Authors: Jang Jisun , Byun Sangmoon , Kim B. Moon , Lee Sunwoo
Published: March 2018

Transition metal-catalyzed silylations have typically involved the use of heterogeneous recyclable catalytic systems.
Multiple conical intersections in small linear parameter Jahn–Teller systems: the DMBE potential energy surface of ground-state C3revisited
Authors: Rocha C. M. R. , Varandas A. J. C.
Published: March 2018

A perspective view of the potential energy surface of ground-state C3highlighting the cusp behavior near equilateral triangular geometries.
Methanol decomposition reactions over a boron-doped graphene supported Ru–Pt catalyst
Authors: Damte Jemal Yimer , Lyu Shang-lin , Leggesse Ermias Girma , Jiang Jyh Chiang
Published: March 2018

In-depth investigations of adsorption and decomposition of methanol over boron-doped graphene supported Ru–Pt catalyst are presented using periodic density functional theory calculations. Methanol decomposition on such catalyst proceeds through formation of methoxide (CH3O) andviastepwise dehydrogenation of formaldehyde (CH2O), formyl (CHO), and carbon monoxide (CO).
Sensing and capture of toxic and hazardous gases and vapors by metal–organic frameworks
Authors: Wang Hao , Lustig William P. , Li Jing
Published: March 2018

This review summaries recent progress in the luminescent detection and adsorptive removal of harmful gases and vapors by metal–organic frameworks, as well as the principles and strategies guiding the design of these materials.
Micelle-enabled clean and selective sulfonylation of polyfluoroarenes in water under mild conditions
Authors: Smith Justin D. , Ansari Tharique N. , Andersson Martin P. , Yadagiri Dongari , Ibrahim Faisal , Liang Shengzong , Hammond Gerald B. , Gallou Fabrice , Handa Sachin
Published: March 2018

Proline-based designer surfactant FI-750-M has been demonstrated to enable selective nucleophilic aromatic substitution of polyfluoro(hetero)arenes by sulfinate salts in water under mild micellar conditions.
Highly selective iodide sensing ability of an anthraquinone-derived Schiff base in semi-aqueous medium and its performance in antioxidation, anti-inflammation and HRBC membrane protection
Authors: Venkatesan Vetriarasu , Kumar S. K. Ashok , Bothra Shilpa , Sahoo Suban K.
Published: March 2018

In this study, a new iodide (I−) ion selective chromogenic receptor (3) was developed by reacting 9,10-anthraquinone with 2,4-dinitrophenylhydrazine.
A promazine derivative-oriented chemical sensor for ultra-sensitive chromium determination
Authors: Saigl Z. M. , Ahmad W. , Mohammed G. I. , Alwael H. , Al-Bagawi A. H. , Al-Eryani D. A. , El-Shahawi M. S.
Published: March 2018

The study reports a simple and highly selective spectrofluorometric method for trace determination and speciation of chromium(iii & vi) species in water using 10-(3-dimethylaminopropyl) phenothiazine hydrochloride, namely, promazine hydrochloride (PMH) as a fluorescence tagging reagent.
Lipid composition dictates serum stability of reconstituted high-density lipoproteins: implications forin vivoapplications
Authors: Gilmore Sean F. , Carpenter Timothy S. , Ingólfsson Helgi I. , Peters Sandra K. G. , Henderson Paul T. , Blanchette Craig D. , Fischer Nicholas O.
Published: March 2018

Nanolipoprotein assembly, and dissociation through contact with serum, as assessed through size-exclusion chromatography.
Catalytic asymmetric construction of spiropyrrolidines via 1,3-dipolar cycloaddition of azomethine ylides
Authors: Fang Xin , Wang Chun-Jiang
Published: March 2018

In this review, recent progress on the catalytic enantioselective synthesis of chiral spiropyrrolidine derivatives via 1,3-dipolar cycloaddition of azomethine ylides has been discussed.
Bridged oxide nanowire device fabrication using single step metal catalyst free thermal evaporation
Authors: Coşkun Mustafa , Ombaba Matthew M. , Dumludağ Fatih , Altındal Ahmet , Islam M. Saif
Published: March 2018

In this study, bridge metal-oxide nanowires grown directly between two Si electrodes on SOI wafer and their electrical performance were investigated.
Efficient protective activity of a planar catechin analogue against radiation-induced apoptosis in rat thymocytes
Authors: Sekine-Suzuki Emiko , Nakanishi Ikuo , Imai Kohei , Ueno Megumi , Shimokawa Takashi , Matsumoto Ken-ichiro , Fukuhara Kiyoshi
Published: March 2018

A planar catechin analogue showed a significant higher protective activity against X-ray induced apoptosis in rat thymocytes than (+)-catechin.
Multiresponsive actuators based on modified electrospun films
Authors: Han Libiao , Xu Jiang , Wang Shuai , Yuan Ningyi , Ding Jianning
Published: March 2018

A flexible actuator was fabricated based on modified electrospun films, which can be stimulated by humidity, light and electricity.
Colloidal probe dynamics in gelatin solution during the sol–gel transition
Authors: Hong Wei , Xu Guozhi , Ou Xiaogang , Sun Weixiang , Wang Tao , Tong Zhen
Published: March 2018

During gelation, non-Gaussianity of the probe arises only at the length-scale crossovers.
A synthesis-enabled relative stereochemical assignment of the C1–C28 region of hemicalide
Authors: Han Bing Yuan , Lam Nelson Y. S. , MacGregor Callum I. , Goodman Jonathan M. , Paterson Ian
Published: March 2018

Synthesis of two advanced C1–C28 fragments revealed the 13,18-syn relative configuration between the 1,6-related stereoclusters in hemicalide.
Folding polymer chains with visible light
Authors: Heiler Carolin , Bastian Simon , Lederhose Paul , Blinco James P. , Blasco Eva , Barner-Kowollik Christopher
Published: March 2018

A simple and versatile tool for generating fluorescent single chain polymer nanoparticles with visible light.
Efficient control of movement in non-photoresponsive molecular machines by a photo-induced proton-transfer strategy
Authors: Shi Qiang , Meng Zheng , Xiang Jun-Feng , Chen Chuan-Feng
Published: March 2018

The first successful application of a PIPT strategy executed by the photoacid 1-MEH in controlling the switch of MIM systems has been demonstrated.
Protein delivery into cells using inorganic nanoparticle–protein supramolecular assemblies
Authors: Scaletti Federica , Hardie Joseph , Lee Yi-Wei , Luther David C. , Ray Moumita , Rotello Vincent M.
Published: March 2018

Direct intracellular delivery of proteins using inorganic nanoparticle–protein supramolecular assemblies.
Kinetic analysis of hexose conversion to methyl lactate by Sn-Beta: effects of substrate masking and of water
Authors: Tosi Irene , Riisager Anders , Taarning Esben , Jensen Pernille Rose , Meier Sebastian
Published: March 2018

Strategies to tailor the Sn-Beta-catalysed methyl lactate process are identified by kinetic and mechanistic insights.
Luminescence mechanisms of ultrasmall gold nanoparticles
Authors: Huang Yingyu , Fuksman Lirit , Zheng Jie
Published: March 2018

The past decade has witnessed a burst of study on ultrasmall gold nanoparticles.
Synthesis of a class of binaphthyl monophosphine ligands with a naphthofuran skeleton and their applications in Suzuki–Miyaura coupling reactions
Authors: Zhou Zihong , Liang Hao , Xia Wang , Chen Huixuan , Zhang Yaqi , He Xuefeng , Yu Sifan , Cao Rihui , Qiu Liqin
Published: March 2018

L6–Pd2(dba)3 showed excellent activity in the Suzuki–Miyaura reaction of sterically hindered and electron-rich aryl halides with aryl boronic acids.
Dynamic kinetic resolution of biaryl atropisomers by chiral dialkylaminopyridine catalysts
Authors: Ma Gaoyuan , Deng Chao , Deng Jun , Sibi Mukund P.
Published: March 2018

Dynamic kinetic resolutions of atropisomers using chiral DMAPs with fluxional chirality.
Impact of molecular orientation on fluorescence emission enhancement in aggregates
Authors: Srujana P. , Radhakrishnan T. P.
Published: March 2018

In addition to intramolecular effects, molecular orientations that curtail intermolecular energy transfer play a critical role in enhancing fluorescence in aggregates.
Immune response effects of diverse vaccine antigen attachment ways based on the self-made nanoemulsion adjuvant in systemic MRSA infection
Authors: Yang Liu-yang , Wei Chao , Yang Yun , Tong Ya-nan , Yang Sha , Peng Liu-sheng , Zuo Qian-fei , Zhuang Yuan , Cheng Ping , Zeng Hao , Zou Quan-ming , Sun Hong-wu
Published: March 2018

Encapsulated formulation of nanoemulsion vaccine induced more potent immune responses against methicillin-resistant Staphylococcus aureus (MRSA) infection, compared with combination and mixture attachment ways.
Development of a FRET-based fluorescence aptasensor for the detection of aflatoxin B1 in contaminated food grain samples
Authors: Kumar Y. V. V. Aswani , R. M. Renuka , J. Achuth , Mudili Venkataramana , Poda Sudhakar
Published: March 2018

The present study aimed to develop an aptamer-based FRET detection strategy for the specific and sensitive detection of AFB1 in contaminated food grains.
Design, synthesis and characterization of a novel bluish-green long-lasting phosphorescence phosphor BaLu2Si3O10:Eu2+, Nd3+
Authors: Liu Jie , Li Gen , Guo Haijie , Liu Dongwei , Feng Peng , Wang Yuhua
Published: March 2018

A newly proposed bluish-green emitting long-lasting phosphor, BaLu2Si3O10:Eu2+, Nd3+, with prominent LLP properties is successfully achieved via a high temperature solid state method.
Friedel–Crafts alkylation reaction with fluorinated alcohols as hydrogen-bond donors and solvents
Authors: Tang Ren-Jin , Milcent Thierry , Crousse Benoit
Published: March 2018

Friedel–Craft alkylation of heterocycle derivatives with β-nitroalkenes was performed in HFIP. The one-pot synthesis of tryptamines could be applied.
Discovery and characterization of a sulfoquinovose mutarotase using kinetic analysis at equilibrium by exchange spectroscopy
Authors: Abayakoon Palika , Lingford James P. , Jin Yi , Bengt Christopher , Davies Gideon J. , Yao Shenggen , Goddard-Borger Ethan D. , Williams Spencer J.
Published: March 2018

Bacterial sulfoglycolytic pathways catabolize sulfoquinovose (SQ), or glycosides thereof, to generate a three-carbon metabolite for primary cellular metabolism and a three-carbon sulfonate that is expelled from the cell. Sulfoglycolytic operons encoding an Embden–Meyerhof–Parnas-like or Entner–Doudoroff (ED)-like pathway harbor an uncharacterized gene (yihR in Escherichia coli; PpSQ1_00415 in Pseudomonas putida) that is up-regulated in the presence of SQ, has been annotated as an aldose-1-epimerase and which may encode an SQ mutarotase. Our sequence analyses and structural modeling confirmed that these proteins possess mutarotase-like active sites with conserved catalytic residues. We overexpressed the homolog from the sulfo-ED operon of Herbaspirillum seropedicaea (HsSQM) and used it to demonstrate SQ mutarotase activity for the first time. This was accomplished using nuclear magnetic resonance exchange spectroscopy, a method that allows the chemical exchange of magnetization between the two SQ anomers at equilibrium. HsSQM also catalyzed the mutarotation of various aldohexoses with an equatorial 2-hydroxy group, including d-galactose, d-glucose, d-glucose-6-phosphate (Glc-6-P), and d-glucuronic acid, but not d-mannose. HsSQM displayed only 5-fold selectivity in terms of efficiency (kcat/KM) for SQ versus the glycolysis intermediate Glc-6-P; however, its proficiency [kuncat/(kcat/KM)] for SQ was 17 000-fold better than for Glc-6-P, revealing that HsSQM preferentially stabilizes the SQ transition state.
Planning Deficits in Children With Specific Language Impairment Are Reflected in Unnecessarily Awkward Grasps
Authors: Sanjeevan Teenu , Rosenbaum David A. , Mainela-Arnold Elina
Published: March 2018

Purpose

Specific language impairment (SLI) affects many children, but its symptomatology is still being characterized. An emerging view, which challenges the notion that SLI is specific to language, is that SLI may actually reflect a domain-general deficit in procedural learning. We explored an extension of this hypothesis that a core deficit in SLI involves a domain-general problem in planning.

Method

We used a dowel-transport task to study the extent to which 13 children with SLI and 14 typically developing (TD) controls (ages over both groups between 8;10 [years;months] and 12;11) would adopt initially awkward grasps that ensured comfortable final grasps when reaching out to move a dowel from 1 position to another (the end-state comfort effect). We predicted that children with SLI would be less likely to use end-state comfort grasps than would TD children.

Results

Contrary to our prediction, when awkward grasps were needed to ensure comfortable final grasps, participants with SLI showed the end-state comfort effect as often as the TD children did. Unexpectedly, however, in trials where awkward grasps were not needed for comfortable final grasps, the participants with SLI used more awkward grasps than did the TD participants after trials in which initial awkward grasps were needed.

Conclusion

We suggest that this perseverative behavior is indicative of a domain-general problem in planning in SLI.
Modified memory‐improved proportionate affine projection sign algorithm based on correntropy induced metric for sparse system identification
Authors: Zhao Ji , Zhang Hongbin , Wang Gang , Liao Xiaofeng
Published: March 2018

A novel memory‐improved proportionate affine projection sign algorithm with correntropy induced metric (CIM‐MIP‐APSA) is proposed to enhance the filtering performance for sparse system identification. Furthermore, a simplified implementation of the CIM‐MIP‐APSA (SCIM‐MIP‐APSA) with low computational complexity is proposed while improving the convergence performance and filtering accuracy. Simulation results demonstrate that the CIM‐MIP‐APSA and SCIM‐MIP‐APSA algorithms outperform the existing works for sparse system identification.
Global accurate estimation of positive‐ and negative‐sequence voltage components for variable frequency AC systems
Authors: Dai Zhiyong , Lv Shuaishuai , Mwaniki Julius K. , Zhang Juxiang
Published: March 2018

In this study, a global observer‐based method is proposed for variable frequency AC systems of more electric aircraft (MEA) to estimate positive‐ and negative‐sequence components and their parameters. Looking at the measurable grid voltage as a parameterised system containing the unknown coefficient – voltage frequency, a mathematical model based on three‐phase grid voltage is established. According to the obtained dynamic model, a global observer is developed to achieve the estimation of positive‐ and negative‐sequence voltage components and their frequency, amplitudes and phase angles with zero steady‐state error. Different from most existing methods which are developed for constant frequency AC grids and only have local convergence, a Lyapunov‐based argument proof provided in this study shows that the proposed observer is able to achieve global asymptotic convergence in theoretical sound. Also, it ensures that the addressed global observer method has a better stability and faster dynamic performance for variable frequency AC grids of MEA. Both simulations and experimental results are provided to validate the proposed global observer scheme.
Fusion of radar sensing and wireless communications by embedding communication signals into the radar transmit waveform
Authors: Geng Zhe , Xu Renhui , Deng Hai , Himed Braham
Published: March 2018

A joint radar‐communication (JRC) system with both radar sensing and communication abilities is proposed to improve spectrum utilisation efficiency. The transmitter of the JRC consists of multiple antenna subarrays transmitting orthogonal waveforms. If the communication receivers are in radar sidelobe directions, the communication data symbols are embedded in the magnitude ratio as well as the phase shift between transmit waveform pairs. In the case of the communication receivers in radar main lobe direction, the data symbols are embedded in the phase shift between transmit waveform pairs only to preserve optimum radar target detection performance. Novel symbol mapping constellation scheme is designed to achieve a high data transmission rate while maintaining a relatively low symbol error rate. The simulation results show that with medium pulse repetition frequency radar waveforms used, the data transmission rate of the proposed JRC system is in the range of Mbits/s.
Formation and growth mechanism of flake‐belt integrative Ag nanocrystals
Authors: Nie Shidong , Zhang Zhiying , Li Jiangtao , Liu Yun , Liu Chunyan
Published: March 2018

Novel flake‐ belt integrative silver (Ag) nanocrystals have been constructed for the first time by a facile one‐ step reduction reaction. In the process, as a modulator, a trace amount of ethylenediaminetetraacetic acid disodium salt played an important role. According to the basic characterisation, a selective deposition and an epitaxial growth mechanism of the reduced Ag were used to explain the formation of the flake‐ belt integrative structure. The high integration of a flake and belt in one particle is completely different from the stacked assembly of nanobelts and flakes. Interestingly, uniform Ag nanobelts were obtained by simply modulating experiments. This work provided a methodology to fabricate metal hierarchical nanoparticles and a new thinking on the growth of Ag nanocrystals.
Error estimates of the third order runge-kutta alternating evolution discontinuous galerkin method for convection-diffusion problems
Authors: Liu Hailiang , Wen Hairui
Published: March 2018

In this paper, we present the stability analysis and error estimates for the alternating evolution discontinuous Galerkin (AEDG) method with third order explicit Runge-Kutta temporal discretization for linear convection-diffusion equations. The scheme is shown stable under a CFL-like stability condition c0τ ≤ ε ≤ c1h2. Here ε is the method parameter, and h is the maximum spatial grid size. We further obtain the optimal L2 error of order O(τ3 + hk+1). Key tools include two approximation finite element spaces to distinguish overlapping polynomials, coupled global projections, and energy estimates of errors. For completeness, the stability analysis and error estimates for second order explicit Runge-Kutta temporal discretization is included in the appendix.
Liquid-liquid Equilibria for Quaternary System of Eugenol (1) + β-Caryophyllene (2) + 1-Propanol (3) + Water (4) at Temperatures 303.15, 313.15, and 323.15 K
Authors: Hidayatulloh Irwan , Nugroho Nurcahyo , Wibawa Gede , Kuswandi Kuswandi
Published: March 2018

In this work, the experimental liquid–liquid equilibrium (LLE) data were measured for quaternary mixtures of eugenol(1) + β–caryophyllene(2) + 1-propanol(3) + water(4) at temperatures 303.15, 313.15, and 323.15 K and at atmospheric pressure. The equilibrium data ware determined by using an equilibrium cell with temperature controlled. Quantitive analysis was performed by using gas chromatography (GC) equipped with thermal conductivity detector and capillary column Rtx-5. The experimental data were then correlated by using the NRTL and the UNIQUAC models. The reliability of these models were tested by compared with the experimental results using a root mean square deviation (RMSD). Based on the RMSD, the NRTL and the UNIQUAC models suited really well and give satisfactory result for the system of eugenol, β–caryophyllene, 1-propanol, and water with the average RMSD of the UNIQUAC and the NRTL models were 0.417% and 0.502%, respectively. Furthermore there was no significant effect of temperatures on the equilibrium composition for the system.
Application of Computational Fluid Dynamics for Modeling of Hydrodynamics and Mass Transfer of Laboratory Scale Crude Palm Oil Degumming Process
Authors: Muharam Yuswan , Kurniawan Aditya , Wirya Andrey S.
Published: March 2018

In this research, computational fluid dynamics was applied to model a laboratory reactor for the degumming of crude palm oil (CPO) involving immiscible liquid-liquid mixing and being controlled by mass transfer. The fluid mixing of CPO and phosphoric acid in the reactor was simulated using multiphase mixture model and standard κ-ε turbulence model in steady state mode. The simulation predicts the distributions of the drop diameter, the dispersed-phase relative velocity, the drop Reynolds number and the interfacial area density. The mass transfer coefficient from experimental work is correlated using the model as Sherwood number Shd = 0.02576 Red0.673Sc0.431 with R2 being 0.91. Finally, the volumetric mass transfer coefficient was calculated and compared to the experiment result.
Mass Transfer Coefficient of Ozone in a Bubble Column
Authors: Ratnawati Ratnawati , Kusumaningtyas Dyah Arum , Suseno Purbo , Prasetyaningrum Aji
Published: March 2018

The effect of flow rate of ozone-containing gas and pH on the mass transfer coefficient of ozone through water in a bubble column reactor has been studied. Ozone was generated from air using a corona discharge ozone generator. The flow rate of air was varied from 2 to 5 L min-1, while pH was varied from 4 to 10. The gas containing ozone was bubbled to the reactor containing 1.5 L of 2% KI solution. The temperature was set at 28±1ºC. The concentration of ozone was determined using titrimetric method every 5 minutes. The results show that the concentration of ozone increases with time, and it reaches a steady-state concentration after 30 minutes of ozonation. The gas flow rate and pH apparently affect both the concentration and the kLa. The highest kLa of 2.1 X 10-2 s-1 is obtained at pH 4 with a gas flow rate of 4 L min-1.
The Effect of Co-solvent on Esterification of Oleic Acid Using Amberlyst 15 as Solid Acid Catalyst in Biodiesel Production
Authors: Ridwan Iwan , Ghazali Mukhtar , Kusmayadi Adi , Diwansyah Putra Resza , Marlina Nina , Andrijanto Eko
Published: March 2018

The oleic acid solubility in methanol is low due to two phase separation, and this causes a slow reaction time in biodiesel production. Tetrahydrofuran as co-solvent can decrease the interfacial surface tension between methanol and oleic acid. The objective of this study was to investigate the effect of co-solvent, methanol to oleic acid molar ratio, catalyst amount, and temperature of the reaction to the free fatty acid conversion. Oleic acid esterification was conducted by mixing oleic acid, methanol, tetrahydrofuran and Amberlyst 15 as a solid acid catalyst in a batch reactor. The Amberlyst 15 used had an exchange capacity of 2.57 meq/g. Significant free fatty acid conversion increments occur on biodiesel production using co-solvent compared without co-solvent. The highest free fatty acid conversion was obtained over methanol to the oleic acid molar ratio of 25:1, catalyst use of 10%, the co-solvent concentration of 8%, and a reaction temperature of 60°C. The highest FFA conversion was found at 28.6 %, and the steady state was reached after 60 minutes. In addition, the use of Amberlyst 15 oleic acid esterification shows an excellent performance as a solid acid catalyst. Catalytic activity was maintained after 4 times repeated use and reduced slightly in the fifth use.
Simulation of the Oxidation and Combustion of Mixed Diesel-Biodiesel Fuel
Authors: Muharam Yuswan , Leonardi Danny , Ramadhania Alisya P
Published: March 2018

A comparative simulation-based research has been set up to obtain valid kinetic models of the oxidation and combustion of biodiesel surrogate and diesel surrogate, as well as mixed diesel-biodiesel surrogates which is used to predict their ignition delay times (IDT). The research consists of the development of the detailed kinetic models of the oxidation and combustion of biodiesel surrogate and diesel surrogate, the validation of the two models with the corresponding experimental IDT data, the merging and the validation of the two models for mixed diesel-biodiesel surrogates. The biodiesel surrogate kinetic model was validated with the experimental IDT data of methyl 9-decenoate at 20 atm and three equivalence ratios. The diesel surrogate kinetic model was validated with the experimental IDT data of n-hexadecane at the pressure ranging from 2 atm to 5 atm and the equivalence ratio of 1.0. The diesel-biodiesel surrogate kinetic model was validated with the experimental IDT data of real diesel-biodiesel fuels for four compositions and at 1.18 atm. The validation results of all models show that the models and the experiments are in good agreement.
Utilization of Solar Energy for Air Conditioning System
Authors: Sutikno Juwari Purwo , Aldina Serlya , Sari Novita , Handogo Renanto
Published: March 2018

The purposes of this research are to do a system simulation of air conditioning utilizing solar energy with single effect absorption refrigeration method, analyze the coefficient of performance (COP) for each absorbent-refrigerant variable and compare the effectivity of every absorbent-refrigerant variable used. COP is a constant that denotes the effeciency of a refrigeration system, that is ratio of work or useful output to the amount of work or energy input. The higher the number of COP, the more efficient the system is. Absorbent-refrigerant (working fluids) variables used in this research depend on its chemical and thermodynamics properties. Steps in this research are including data collection and tabulation from literature and do a simulation of air conditioning system both commercial air conditioning system (using electrical energy) and solar energy air conditioning system with Aspen Plus software. Next, run the simulation for each working fluid variables used and calculate the COP for each variable. Subsequently, analyze and compare the effectivity of all variables used from COP value and economical point of view with commercial air conditioning system. From the result of the simulation, can be concluded that solar air conditioning can achieve 98,85 % of energy savings than commercial air conditioning. Furthermore, from the calculation of COP, the highest COP value is achieved by solar conditioning system with LiNO3-NH3 as working fluid where 55% of the composition is the refrigerant and 45% of absorbent.
Solid-liquid anaerobic baffled reactor treating food waste
Authors: Sumantri Indro , Bagus Priyambada Ika , Hadiyanto Hadiyanto
Published: March 2018

The characteristics of the sauce industrial wastewater is high organic degradable materials, it requires adequate treatment in order to process wastewater is technically and economically feasible. The main treatment to remove high content of organic material is anaerobic process. The presence of a preservative agent in wastewater would lead to disruption of the growth of micro-organisms. Slow the growth of anaerobic bacteria require a solids residence time (solid retention time, SRT) period in anaerobic reactors. This research is to observe the effect of input COD with constant sludge height to the removal of COD. Main equipment process of anaerobic reactor is baffled reactor. Activated sludge used are obtained from the tofu and tempe wastewater treatment unit in Semarang while synthetic wastewater was obtained from dissolution of preservative material product (Del monte sauce). The control parameter was: pH, alkalinity, the ratio of COD: N: P, baffled configuration, wastewater flow rate (20 L/day), addition of micro-nutrient and height of suldge. The variable of reseach was initial COD input. The observed response is: COD removal and pH. The total COD removal for low organic loading (2369.7 mg COD/L) is 80.36 to 98.03 % and for high organic loading (7334 mg COD/L) is 98.15.
Corrosion Inhibitor of Carbon Steel from Onion Peel Extract
Authors: Muhammad Samsudin Asep , Samudra Pamungkas Aribella , Estu Nugraheni Ratih
Published: March 2018

Carbon steels composed by two main elements, they are iron (Fe) and carbon (C) elements which widely used in industrial because of its resistance and more affordable than stainless steel, but their weakness is they have low corrosion resistance. One way to modify carbon steel is by coating them with antioxidant compounds that can delay, slow down, and prevent lipid oxidation process, which obtained from onion peel extract. Several studies on corrosion inhibitors have been performed. However, the efficiency was not reach the optimum. This study aims to examine the effect of onion peel extract concentration on the efficiency of corrosion inhibitor and characterization of the green corrosion inhibitor from onion peel extract. This research method begins by extracting onion peel to 200 ml solvent which we use aquadest and methanol and mixed with 5 grams of crushed onion peel, then let them be extracted for 60 minutes with room temperature. Once it was filtered and the solution obtained, followed by evaporating process with rotary evaporator to decrease the content of solvent. The product is ready to be used as a green corrosion inhibitor of carbon steel in 1 mol/L HCl. While the analysis used is HPLC qualitative analysis, and electroplatting process. The impedance is measured at a frequency of 100 kHz to 4 mHz with an AC current of 10mV. Inhibitor concentrations are vary between 2 ml and 4 ml of onion peel extract. Electroplatting is done within 30 minutes with 10 minutes each checking time. Furthermore, quantitative analysis was done for the analysis of corrosion rate and weight loss. Based on HPLC analysis, it is known that the extract of onion peel contains 1mg/L of quercetin, which is belong to flavonoid group as green inhibitor. While electroplatting process, aquadest solvent having average efficiency of 99,57% for 2 ml of extract, and 99,60% for 4 ml of extract. Methanol solvent having average efficiency of 99,52% for 2 ml of extract and 99,74% for 4 ml of extract. In line, methanol have more possibilities to gain flavonoid out to act as green inhibitor than aquadest due to its polarity. It is suggested to cover up the extract of onion peel to avoid them against sunlight, to keep the flavonoid not damaged.
Biosorption of Lead (II)–containing Sasirangan Textile Wastewater using Nanocomposites of Eleocharis dulcis Fibers with Iron (III) Nanoparticles as Adsorbent
Authors: Irawan Chairul , F. Nata Iryanti , D.Putra Meilana , Ristianingsih Yuli
Published: March 2018

This research focuses on the study of biocomposite nanoparticles of Eleocharis dulcis (ED) as potentials biosorbent to reduce the concentration of lead (II) ion containing Sasirangan textile industry wastewater. Eleocharis dulcis, locally named as Purun Tikus, has been developing becomes the biocomposites nanomaterial and valuables material in this research. Batch experiments were carried out to considering the kinetic of biosorption of lead onto the adsorbent, evaluating the effects of lead ion equilibrium concentration, equilibrium pH, and temperature on the adsorption of lead (II). Kinetic data of lead (II) biosorption onto EDB and EDB-MH revealed that equilibrium time was reached within 2 h, and the isotherm data showed that the Langmuir maximum adsorption capacity of the EDB-M and EDB-MH at pHe of 6±0.2, room temperature were 150.43 mg/g and 180.92 mg/g, respectively. The thermodynamic of lead (II) biosorption onto the adsorbent implied the biosorption was spontaneous and endothermic indicating by increased in temperature would increased in adsorption capacity.
The Current Density on Electrosynthesis of Hydroxyapatite with Bipolar Membrane
Authors: Nur Adrian , Jumari Arif , Budiman Anatta W , Nazriati Nazriati , Fajaroh Fauziatul , H Fariza Jeihan , L Anisa Tovaliery
Published: March 2018

Synthesis of hydroxyapatite by electrochemical method was has been successfully done. The novelty of this research is used of the bipolar membrane to separate electrolysis chamber. The bipolar membrane is used to keep the cations still around the cathode and react to form hydroxyapatite. The aim of this paper was to compare the current density on electrosynthesis of hydroxyapatite with and without bipolar membrane and the effect of current density on electrosynthesis. The electrosynthesis was performed at 2 hours at 400 to 600 mA/cm2 at room temperature. The bigger the current density, the more pure HA formed. The electrosynthesis of hydroxyapatite with bipolar membrane more effective than without bipolar membrane. The formation of HA is very effective in the cathode chamber. HA can be formed at low current density. In electrosynthesis with the bipolar membrane, particles of HA are nanosheet flower-like. The nanosheet flower-like HA growth at 1.6 A to 2 A.
Production of Lactic Acid from Empty Fruit Bunch of Palm Oil Using Catalyst of Barium Hydroxide
Authors: Puspita Aini Apsari , Lee Hyung Woo , Parningotan Sitompul Johnner , Rasrendra Carolus Borromeus
Published: March 2018

Lactic Acid as a platform chemical has broad application in various industries, especially in the production of Poly Lactic Acid (PLA) for biodegradable plastic. Empty fruit bunch (EFB), abundant by product from palm oil mill industry, is one of potential feedstock to be used in the production of lactic acid from lignocellulose biomass. EFB contains high cellulose and hemicellulose about 37– 59.7% w/w and 16–28% w/w, respectively. The aim of this paper is to study the effects of the operating conditions, such as temperature, reaction time, biomass loading, and catalyst concentration on the yield of lactic acid using barium hydroxide as alkaline catalyst. EFB pretreatment with steam explosion was applied to remove lignin content. The results showed that pretreatment reduced the lignin content from 22.66% to 9.69% w/w. Meanwhile, hemicellulose and cellulose increased from 14.40% to 16.40% w/w and 29.37% to 63.57% w/w, respectively. The highest yield of lactic acid was 21.57% C-mol, achieved by using 0.25 M Ba(OH)2 as the catalyst, with 5% w/v biomass loading, temperature 240°C, during 4 h reaction times. The yield was approximately equal to yield of lactic acid (~ 20%) compared with Pb2+ as the catalyst for EFB conversion although the later catalyst produced fewer by products during conversion.
Enhancement Performance of Hybrid Membrane Zeolite/PES for Produced Water Treatment With Membrane Modification Using Combination of Ulta Violet Irradiation, Composition of Zeolite and Thermal Annealing
Authors: Djoko Kusworo Tutuk , Rahmatya Gerhana Annizah , Hanifah Angga Putra Noor
Published: March 2018

Produced water is a wastewater from oil production that must be treated well. Membrane is one alternative of water treatments technology based on filtration method. However, in the use of membrane, there’s no exact optimal variable that influences membrane performance.This underlying research to assess factors that influences membrane performance to obtain optimal condition. Therefore, the objectives of this study are determining the effect of variable process in membrane fabrication and several modification techniques on membrane performance. The membranes were fabricated via dry-wet phase inversion method. The process variables of this experiment are varying the Zeolite concentration by low level 1% weight and 3% weight, UV irradiation time low level 2 minutes and high level 6 minutes, thermal annealing temperature low level 160°C and high level 180°C. The experiment runs were designed using central composite design. From the research that has been perfromed, PES/Zeolit membrane has a higher permeability after being irradiated by UV light and denser pore after heating and the longer of annealing time.
Optimum parameters for treating coolant wastewater using PVDF-membrane
Authors: Yuliwati Erna , Ismail Ahmad Fauzi , Mohruni Amrifan Saladin , Mataram Agung
Published: March 2018

Chemical oxygen demand (COD removal on ultrafiltration membrane were studied from treating of coolant wastewater. The membranes were fabricated via the dry-jet wet spinning method. The experiment was conducted using synthetic coolant wastewater as effluent, and an experimental set-up consist of membrane reservoir was used throughout the investigation. Deposition and accumulation of suspended solids on the membrane surface during filtration were prohibited with continuous aeration. Membrane performance was measured as well as flux and COD removal efficiency. The RSM was performed to investigate the optimised process conditions for treating coolant wastewater. Results using RSM-approximation have demonstrated the improvement in COD removal of 99.63%. This improvement is achieved by optimised process conditions of mixed liquor suspended solids (MLSS) concentration, air bubble flow rate (ABFR), hydraulic retention time (HRT) and pH at 6.00 g/L, 3.05 ml/min, 280.50 min, and 6.50 respectively.