bluuebunny/crossref_metadata_2025 huggingface dataset:
Critical Velocity during Intermittent Running with Changes of Direction
Authors: KIRBY BRETT S. , BRADLEY ERIC M. , WILKINS BRAD W.
Published: August 2018

Purpose

We tested the hypothesis that critical velocity (CV) during intermittent running with changes of direction is reliably and accurately identified from a simple shuttle field test. We also tested the hypothesis that CV during intermittent running with changes of direction running is not equivalent to continuous linear running.

Methods

Young adults performed a custom shuttle test of intermittent sprint running to reveal CV. Sprints were 18.3 m per direction, with rest between sprints of 15 s for 3 min, 10 s for 2 min, and no rest for 2 min (7 min total). To test reliability, the CV shuttle test (CVST) was performed twice. To test validity, blood lactate was assessed during two separate trials inclusive of 5% above or below CVST end velocity. To explore task specificity, CV during CVST was compared to CV obtained from three linear running time trials.

Results

Total distance and CSVT end test velocity were similar between visits (864 ± 21 m and 3.23 ± 0.13 m·s−1 vs 900 ± 30 m and 3.21 ± 0.15 m·s−1, respectively). At 5% above CVST end velocity, all subjects failed to complete 20 min and had unstable blood lactate values. A steady state blood lactate profile was observed during trials 5% below end velocity and all subjects completed the trial. The CV from the CVST was lower than the CV from linear running (△ −17% ± 6%), highlighting the importance of test specificity for threshold determination.

Conclusions

The CVST provides a reliable and accurate determination of CV and can be used by coaches, athletes, and trainers to better understand the physiological impact specific to practice or competitions involving intermittent change of direction running.
Adverse childhood experiences in the children of the Avon Longitudinal Study of Parents and Children (ALSPAC)
Authors: Houtepen Lotte C. , Heron Jon , Suderman Matthew J. , Tilling Kate , Howe Laura D.
Published: August 2018

Background: Exposure to adverse childhood experiences (ACEs) is a risk factor for poor later life health. Here, we describe the ACE variables measured in the children of the Avon Longitudinal Study of Parents and Children (ALSPAC) study, and a method used to derive summary measures and deal with missing data in them.   

Methods: The ALSPAC data catalogue (59 608 variables) was searched in September 2017 for measures on adversity exposure between birth and 18 years. 6140 adversity questions were then screened for conforming to our ACE definitions and suitability for dichotomisation. This screening identified 541 questions on ten ‘classic’ ACEs (sexual, physical or emotional abuse, emotional neglect, substance abuse by the parents, parental mental illness or suicide attempt, violence between parents, parental separation, bullying and parental criminal conviction) and nine additional ACEs (bond between parent and child, satisfaction with neighbourhood, social support for the parent, social support for the child, physical illness of a parent, physical illness of the child, financial difficulties, low social class and violence between child and partner). These were used to derive a binary construct for exposure to each ACE. Finally, as cumulative measures of childhood adversity, different combinations of the 19 ACE constructs were summed to give total adversity scores. An appropriate strategy for multiple imputation was developed to deal with the complex patterns of missing data.

Results: The ACE constructs and ACE-scores for exposure between birth and 16 years had prevalence estimates that were comparable to previous reports (for instance 4% sexual abuse, 18% physical abuse, 25% bullied, 32% parental separation).

Conclusions: ACE constructs, derived using a pragmatic approach to handle the high dimensional ALSPAC data, can be used in future analyses on childhood adversity in ALSPAC children.
Where does it start?
Authors: Siddon Roz
Published: August 2018

Roz Siddon believes communication is an essential skill in any area of dentistry. Here, she talks us through the patient journey
Nutrition and oral health
Authors: Middleton Anna , Medlin Sophie
Published: August 2018

The importance of a healthy lifestyle and diet are common messages shared by dental and medical professionals alike. Here, dental hygienist Anna Middleton and dietitian Sophie Medlin collaborate
Life-saving essentials
Authors: Jevon Phil
Published: August 2018

Phil Jevon walks us through the procedure for placing a patient in the recovery position in this peer-reviewed CPD article
‘Dental Showcase, here I come…’
Authors: Jones Joanne
Published: August 2018

Dental nurse Joanne Jones is treatment coordinator at London practice, Sparklysmile. Here, she shares her passion for her role and how dental nurses can provide a five-star service
Meetings – the dark arts revealed
Authors: Ainsworth Steve
Published: August 2018

Steve Ainsworth shares his take on the seven deadly sins – from sabotage to manipulation and everything in between
Empower them to fly
Authors: Fowler John
Published: August 2018

In the fourth part of this series on professional relationships, John Fowler explores the importance of positive working relationships with junior team members
Specialist work in a primary care setting
Authors: Bakare Kemi
Published: August 2018

Kemi Bakare considers oral surgical care and the dental nurse
Guns to gums – a journey of lifelong learning
Authors: Howe Shaun
Published: August 2018

Shaun Howe is a dental therapist working in the public dental service for NHS Shetland, is an NEBDN examiner and a dental nurse tutor. Here, he shares his career path
Implant care – and you
Authors: Bones Marie
Published: August 2018

Marie Bones considers the dental nurse's important role
Effect of Europium (III) Oxide doping on the nanoscale ceramic Stannates(MSnO3) of Ca, Ba upon photo luminescence, catalytic degradation and anti-microbial activity – Green approach
Authors: S Sudhaparimala , Suvaitha S Prashanna
Published: August 2018

The study of alkaline earth doped stannate ceramics of Barium and Calcium is being carried out to explore more on the phosphorescent applications. The present study is an energy and cost-efficient green approach towards the preparation of Europium (III) doped stannate of Calcium and Barium in the nano scale as it involves the biowaste of egg shell as a precursor for calcium carbonate and the plant extract of aloe vera as the reaction medium and a comparatively lower calcination temperature than reported so far. The structure, phase purity, surface morphology and applications in terms of photo luminescence, photo catalytic and anti-microbial activities have been investigated. The doping of alkaline earth metal of Europium in lower weight percentage (lesser than one) was carried out at lower processing temperatures than reported earlier. There was a phase transition in the case of barium stannate upon doping and there were observable changes in crystallite size, morphology and microstructure in the case of Stannates of Calcium and Barium. The results of photo luminescence study and the photo catalytic degradation of methylene blue dye were encouraging. The anti-microbial study in terms of toxicity of the doped samples in smaller dosages upon Pseudomonas aeruginosa, Staphylococcus aureus provided a new dimension to their application.
Study of dissolved Copper(II) Speciation at Coastal Water of Peninsular Malaysia
Authors: Godon Edrianna , Nizam Mohamed Khairul , Azrul Gani Mohamad , Johan Shamsuddin
Published: August 2018

Samples from Perhentian and Pangkor Island Marine Park, Peninsular Malaysia were analyzed for Cu(II) speciation by using CLE-AdCSV. Northeast monsoon effect was studied in Perhentian and compared with Pangkor. Excess concentration of CuL found for all stations in both islands showed >99.5% of total dissolved Cu (dCu) was bound to Cu (II) complexing ligands. The log K’CuL>12 data indicated the presence of strong natural ligands (L1) in Perhentian Island. Lower log K’ (log K’=10 to 12) and two types of ligands (L1 and L2) were found in Pangkor Island. The ratio of CuL/dCu was analysed to see the ligand distributions, and saturation rate with dissolved Cu. Statistical analysis showed weak relationship between the in-situ parameters to log K’ values (p>0.05). The log K’CuL (PP: 12.00-12.96, PG: 10.93-12.840) data suggested that the dissolved Cu are used by marine organisms, thus preventing the free Cu2+ ions to be produced.
Improvement in Crystallizability and Melt Flow Property of Linear Poly(L-lactide) Bioplastic by Blending with Star-shaped Poly(L-lactide)
Authors: Baimar Yodthong , Srisuwan Yaowalak
Published: August 2018

This research focuses on the crystallizability and melt flow property of linear poly(L-lactide) (1-PLL) by blending with star-shaped 16-arm PLL (16-PLL). The 1-PLL/16-PLL blends were chain extended during melt blending using an epoxy-based chain extender. The crystallinities of the 1-PLL/16-PLL blends increased with the 16-PLL blend ratio and chain extension reaction. The 16-PLL enhanced formation of branched PLL during chain extension was confirmed by thermogravimetry, and improved the melt flow property of the blends. Stresses at break of the compressed blend films were improved slightly by the 16-PLL blending and chain extension. In conclusion, the 16-PLL could be used as a nucleating agent and a melt strength enhancer for linear PLL.
Effect of different Current density on Properties of Electrodeposited Ni-Co-Cr Thin Films
Authors: Meena S. P. , Ashokkumar R.
Published: August 2018

NiCoCr thin films were electroplated for different current density. FCC structured crystals were observed in XRD study. Coercive force and magnetization value exhibits soft magnetic nature. Electroplated NiCoCr films with electrolytic current density (2, 3, 4 and 5 mil.Amp/cm2) shows uniform deposition on the substrate. Cobalt composition was minimum as 21.31 wt% for current density 5 mA/cm2. The consistence of chromium and nickel increased while current density was improved. Thin films deposition with high current density shows low hysteresis loss and soft magnetic nature.The hardness of deposits increases when current density is increased.
Estimation of Lattice Constants and Band Gaps of Group-III Nitrides using Local and Semi Local Functionals
Authors: Arora Sandeep , Singh Ahlawat Dharamvir , Singh Dharambir
Published: August 2018

We performed the optimization of lattice constants of Group- III nitrides (InN, AlN, GaN) in wurtzite and Zinc blende structures using various semilocal exchange correlation functional in generalized gradient approximations (GGA) namely PBE, WC, PBEsol in addition to local density approximation (LDA) functional. We used these optimized lattice parameters to predict the band gap values using modified Becke Johnson exchange potential with original and improved parameterization as suggested by David Koller for semiconductors having band gap values below 7eV. Among the different functionals considered, PBEsol optimize the lattice parameters with smallest mean error (0.00639 Å) relative to experimental values, while WC approximation with a slightly greater value of mean error (0.00513 Å). It is shown that mBJLDA approximation improves the band gap for the materials studied when compared with LDA and GGA results. It is also shown that LDA optimized parameters with mBJLDA approximation, which leads to mean error of 0.162 eV reproduces the experimental band gap in most efficient way.
CuO Coated Electrochemically Generated Textile Wastewater Sludge and CuO Coated GAC as Potential Nano-adsorbents for Color Removal from Real Textile Wastewater
Authors: H, S. Mahesh Srikantha , M Sahana
Published: August 2018

A laboratory scale setup was used to remove color from real textile wastewater (TWW) using nano CuO coated electrochemically generated sludge and nano CuO coated GAC. ECC studies were conducted in batch-mode to generate sludge treating real TWW using pre-optimized 4SS electrodes using a 1.5L reactor operated at cell voltage of 18V and current density 180A/m2 at an agitation speed of 500rpm for 60min electrolysis time. SEM, FTIR and XRD analysis confirmed CuO material successfully coated/decorated on electrochemically generated sludge of size ~0.3-0.5mm and GAC of size ~0.5mm. To check the color removal efficiencies from TWW the batch adsorption studies were conducted for adsorbent dose, stirring time and pH. The optimal operating conditions achieved at pH-4, dose of 0.6g/L and 30min contact time for CuO-sludge nano-adsorbent achieving 50-55% color removal. Similarly, for CuO-GAC nano-adsorbent the optimal conditions obtained at pH-4, 0.5 g/L dose and 20min contact time achieving ~100% removal.
Vibrational Spectra of Ozone (O3) Using Lie Algebraic Method
Authors: Vijayasekhar J.
Published: August 2018

We have calculated the vibrational frequencies of Ozone (O3) upto second overtone using Hamiltonian operator which is based on the Lie algebra. The determined symmetric and antisymmetric fundamental vibrational frequencies by Lie algebraic method are compared with experimental data. It has been observed that results from the method reveal near to the exact, consistent with the experimental data.
PtNi and CoNi Film Electrocatalysts Prepared by MOCVD for the Oxygen Reduction Reaction in Alkaline Media
Authors: Garcia-Contreras M. A. , Fernandez-Valverde S. M. , Vargas-Garcia J. R.
Published: August 2018

CoNi and PtNi film electrocatalysts were prepared by Metal-Organic Chemical Vapour Deposition (MOCVD) and their electrocatalytic activity for the oxygen reduction reaction (ORR) in 0.5 M KOH was investigated by cyclic voltammetry and Rotating Disk Electrode techniques. Experiments included working electrodes of Co, Ni and Pt prepared also by MOCVD for comparison. The film electrocatalysts were characterized by X-ray diffraction, Scanning Electronic Microscopy and Energy dispersive X-ray analysis. Films thickness was about 200-250 nm and nanocrystallites were found in the range of 12 to 30 nm. In the same experimental conditions, the overpotential for the ORR at a current density of 1 mA cm-2 for PtNi film was 120 mV lower than the overpotential of Pt film electrocatalyst, and an enhanced activity was observed on PtNi with respect to Pt. The electrochemical response for the oxygen reduction reaction on CoNi film was higher than those of elemental Ni and Co films obtained by MOCVD. A good stability was obtained in a chronoamperometry test for the PtNi electrode, only affected by oxygen flow variations.
Fabrication and Characterization of Gold Nano-gaps for ssDNA Immobilization and Hybridization Detection
Authors: Dhahi Th. S. , Hashim U. , Ahmed N. M. , Nazma H.
Published: August 2018

We develop a method for fabricating the nano-gaps directly by using just photolithography and wet etching processes without any nano lithography or difficult techniques. It shows that this resolution enhancement allows one to fabricate metal electrodes with separation from arbitrarily large to fewer than one hundred nanometers. Furthermore, because these nano-gaps are on a thin film, they can be imaged with high-resolution transmission electron microscopy (HRTEM). Efforts toward achieving electrical contact to nanostructures have been active for over a decade. Even though several devices based on “nano-gaps” – two gaps separated by a nanometer-scale distance - have been demonstrated, their realization has remained a significant challenge. Even the best methods are highly labor-intensive and suffer from low yield and poor geometrical control. Most nano-gaps are also incompatible with high resolution transmission electron microscopy (HRTEM) and scanning electron microscopy (SEM). As a consequence, the proof of the nano-gap quality and content in past studies has been indirect. High-resolution imaging is therefore required to ensure the quality of nano-gaps and to be able to identify possible artifacts. This project presents a unique vertical nano-gap biosensor that can detect changes in DNA structure. Using a size reduction to interrogate samples between the nano-scale gaps, this biosensor will be sensitive enough to record the conformational changes for ss-DNA.
Fabrication of Nanoporous Copper Ribbons with a Broad Range of Pore Size and Its Application in Lithium-ion Batteries
Authors: Zheng Jiwei , Zhang Shichao , Liu Wenbo , Xing Yalan , Du Zhijia
Published: August 2018

Nanoporous copper (NPC) ribbons with an average pore size of 5~500nm were fabricated by chemical/electrochemical dealloying of Mn55Cu45 alloy. The influence of different kinds of driving forces on Cu atoms surface diffusivity (Ds), which determines the pore sizes of the resultant NPC, was also systematically investigated. The Ds by chemical dealloying with and without surfactants is about 1.08×10-20 m2 s-1 and 1.79×10-18 m2 s-1, through which NPC with pore size of ~5nm and ~50nm was produced, while, in electrochemical dealloying with 0 V SCE potential, Ds and pore size increase to 1.16×10-15 m2 s-1 and ~500nm respectively. The three dimensional NPC ribbons with the largest pore size (500nm) was chosen as the current collectors to fabricate three dimensional tin thin-film anodes (3D-TTA) with homogeneous tin layers on the ligaments by electroless plating for lithium-ion batteries (LIBs). The 3D-TTA exhibits first discharge capacity of 790 mAh g-1, 45% capacity retention after 10 cycles, indicating a promising application in LIBs.
Comparison of the Photoelectrochemical Characteristics of Dye-Sensitized Inverse-Opal Electrodes Prepared by Various Liquid-Phase Methods
Authors: Matsushita Sachiko , Nishiyama Chie , Kato George , Nakajima Akira , Isobe Toshihiro , Hashimoto Takuya
Published: August 2018

The photovoltaic characteristics (short circuit current, open circuit voltage, fill factor, and photon-to-electron conversion efficiency) and electrochemical impedance measurements of normal and inverse-opal dye-sensitized electrodes were carried out in a transparent electrolyte (0.6 M triethhanolamine/0.5 M lithium perchlorate in acetonitrile) using three different methods; electrophoretic deposition, TiCl4 coating, and liquid-phase deposition (LPD). X-ray diffraction (XRD) analysis revealed that each electrode was composed of anatase TiO2. The impedance elements discussed previously were substrate resistance (R0), interface resistance at indium tin oxide (ITO)/titanium oxide (TiO2) (R1), contact resistance between TiO2 particles (R2), interface resistance at TiO2/dye/electrolyte and counter electrode/electrolyte (R3), and diffusion resistance of the electrolyte (R4). The internal resistances of inverse opal electrodes were varied with the preparation methods, especially in relation to the contact resistance between R2 and R3. The electrode prepared by LPD exhibited the smallest internal resistances and the highest photon-to-electron conversion efficiency among the three methods.
A Study on the Hydrogen Evolving Activity of Electroplated Ni-P Coating by Using the Taguchi Method
Authors: Lee Hung-Bin , Hsu Chen-Hsiung , Wuu Dong-Sing
Published: August 2018

The optimal catalytic activity of the electrodeposited Ni-P coating with the control of the process parameters was performed in this study by using Taguchi’s method. The controlled process parameters included current density, duty cycle and the concentration of the phosphorous acid in the electrolyte. The correlation among the controlled parameters and the resulted hydrogen evolution reaction (HER) activity was discussed with emphasis on the influence of the P content, internal stress, roughness and grain size of the coating. The optimal HER property was obtained for the electrodeposition of Ni-P coating with a phosphorous acid concentration of 5g/l, current density of 16A/dm2 and duty cycle of 100 %. The resulted Ni-P coating with a better HER property was the one with P content 3at%, an internal stress higher than 10MPa, grain size 10~15nm and surface roughness higher than 100nm. In addition, the cracking of the coating due to high internal stress favored the raise of the HER activity.
Ti-doped Lithium Iron Phosphate (LiFePO4) Cathode Materials: Synthesis and Electrochemical Evaluation
Authors: Ding Keqiang , Li Wenjuan , Yang Hongwei , Wei Suying , Guo Zhanhu
Published: August 2018

The Ti doped LiFePO4 samples, i.e., LiFe1-xTixPO4 (X=0.01, 0.03 and 0.05), were prepared by a modified solid state method. The obtained samples were thoroughly characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). XRD patterns indicated that an olivine-type LiFePO4 was fabricated, and SEM images revealed that the particle size of LiFe0.99Ti0.01PO4 was the smallest among the obtained samples. The charge-discharge curves showed that LiFe0.99Ti0.01PO4 delivered the discharge capacity of 153.5 mAh/g at 0.2 C, the largest one among the as-prepared samples, which is rather different from the published report that LiFe0.97Ti0.03PO4 manifested the most promising cycling performance among the samples of LiFe1-xTixPO4 (X=0.01, 0.03, 0.05, 0.07 and 0.09).
Fabrication and Rate Performance of Spherical LiFePO4 Nanoparticles for High–power Lithium Ion Battery
Authors: Huang Bing , Zheng Xiaodong , Lu Mi , Zhou Yiming , Chen Yu , Dong Su , Qiao Yu
Published: August 2018

The spherical LiFePO4/C nanoparticles are synthesized by modified carbothermal reduction method. XRD patterns show that the LiFePO4 compound is orthorhombic crystal structure. SEM and TEM results indicate that the LiFePO4 composite had a spherical morphology with carbon coated and the particle size is nanoscale. Charge/discharge tests and CV curves show that as-prepared sample exhibits discharge capacity of 153 mAh g-1 at 0.2 C rate with high electrode reaction reversibility. The discharge capacities of the material are 150, 132, 119, 111, 103 and 96 mAh g-1 at 1 C, 5 C, 10 C, 15 C, 20 C and 25 C rate and high voltage plateaus are achieved. The good rate performance of the composite is due to its nano particle size and spherical morphology, which reduced the diffusion path of lithium ions and electrons, increased the conductive specific surface and improved the processability of the LiFePO4 cathode.
Electrochemical Properties of Nanostructured AgxPt100-x/C Electrocatalyst for Oxygen Reduction Reaction
Authors: Godínez-García Andrés , García-García Alejandra , García-García Alejandra , Martínez-Tejada H. Vladimir , Pérez-Robles J.F. , Solorza-Feria O.
Published: August 2018

In this work, AgxPt100-x/C (x = 60, 80, 90 and 95) colloidal nanostructured electrocatalysts for the oxygen reduction reaction (ORR) were prepared by sequential reduction of AgNO3 and H2PtCl6 using an ultrasound-assisted colloidal method. The synthesized materials were characterized by UV/Vis spectroscopy, XRD, EDS and HRTEM. In addition electrochemical measurements were performed using cyclic voltammetry (CV) and thin-film rotating-disk electrode (TF-RDE) technique in 0.5 M H2SO4 at room temperature. Results of the physical characterization showed ring-like morphology of the nanostructured catalyst with a size distribution in the range of 6-16 nm. From steady polarization measurements, the AgxPt100-x/C nanocatalysts showed electrocatalytic activity towards the ORR like that obtained for Pt/C catalyst under the same experimental conditions and also favored the multielectron (n=4e-) charge transfer process to water formation (i.e., O2+4H++4e- → 2H2O).
DFT Study of the CO Poisoning Effects on PdxCu1-x (110) Surface
Authors: López-Chávez Ernesto , García-Quiroz Alberto , Peña-Castañeda Yesica A. , Castillo-Alvarado Fray De Landa , Cabañas-Moreno Gerardo , Martínez-Magadán José Manuel
Published: August 2018

CO contaminants play a significant role in modifying the performance of proton exchange membrane fuel cells (PEMFC). Pt is probably the most common catalyst being used today to absorb CO in the PEMFC, yet recent studies have shown that the use of Pd alloys such as Pd-Cu can increase the fuel cell efficiency versus a pure Pt catalyst. In this work, we examine the adsorption of CO onto PdxCu1-x (110) surfaces, with different values of x, in order to improve the CO tolerance. Understanding how molecules interact with such surfaces is the first step in understanding catalytic reactions. The study here presented was done using CASTEP, a computational code based on the plane-wave pseudopotential method of functional density theory. The surface structure of PdxCu1-x (110) was optimized and then the state density-functional, the repulsion energies and the chemisorption for CO on PdxCu1-x(110) were calculated. The results indicate that chemisorption energies of CO on PdxCu1-x are highly dependent on the concentration x of the alloy. In addition, density of states analysis indicate that the poisoning effect is partially due to the loss of Pd-Cu(d) electrons upon CO adsorption.
An Easy Route to Synthesize Novel Fe3O4@Pt Core-shell Nanostructures with High Electrocatalytic Activity
Authors: Sánchez-Padilla Nora Mayté , Montemayor Sagrario M. , Varela F.J. Rodríguez
Published: August 2018

In this work, the effect of changing the stirring method and temperature on the physicochemical properties of metallic nanoparticles and core-shell nanostructures is shown. Magnetic (MS), mechanical (UT) and ultrasonic (USS) stirring are the methods of synthesis. The effect that, temperatures between 0 and 50 °C, has on the structure and particle size of Fe3O4 nanoparticles is evaluated. The results indicate that Fe3O4 prepared by the three methods presents a spinel-type crystalline structure. An increase in the synthesis temperature leads to highly crystalline powders. Afterwards, Pt is deposited by the UT method on Fe3O4 to form Fe3O4@Pt core-shell nanostructures. It is important to mention that the time used for the synthesis of the nanoparticles and the core-shell nanostructures is only one minute. The presence of Fe3O4 and Pt is confirmed by XRD and XPS. The metallic Pt phase is confirmed because the binding energy of Pt 4f 7/2 is associated to platinum in the zero-valent state. We evaluated the electrochemical activity of the Fe3O4@Pt core-shell nanostructures for the oxygen reduction reaction (ORR). The novel materials show a high electrocatalytic activity and the Koutecky-Levich analysis indicates that the reaction follows a 4 electron transfer mechanism on the Fe3O4@Pt nanostructures prepared by the three stirring processes. Moreover, the mass specific activity of the core-shell materials is as high as that obtained from the Pt-alone catalysts, suggesting that the amount of Pt in these electrodes can be reduced without decreasing the performance.
Parallel Connection and Sandwich Electrodes Lower the Internal Resistance in a Microbial Fuel Cell
Authors: Ortega-Martínez Areli , Juárez-López Katy , Solorza-Feria Omar , Ponce-Noyola María T. , Ríos-Leal Elvira , Rinderknecht-Seijas Noemí F. , Poggi-Varaldo Héctor M.
Published: August 2018

The aim of this work was to design and characterize a novel, multiface parallelepiped MFC in the perspective of decreasing the internal resistance (Rint) and increasing the volumetric power (Pv) output. The cell was fitted with a ‘sandwich’ cathode-membrane-anode assemblage in five of its faces, and possessed a ratio electrode surface area-to-volume ξ (csi) of 19 m-1 .

When the 5 faces of the MFC-P were connected in series, the Rint was 601 Ω with a voltage of 0.52 V. Characterization of the cell with the 5 faces connected in parallel gave a Rint of 62 Ω with a voltage of 0.5 V that corresponded to external resistance of 56 k Ω in the polarization procedure. This result was ascribed to both the changes in cell architecture and decrease of the inter-electrode distance as well as the parallel connection. The Pv of the new MFC-P achieved values of 62 and 570 mW/m3 for series and parallel connection, respectively.

Molecular ecological techniques were used to analyze the bacterial diversity of biocatalyst used in new design MFC-P. They showed a low species richness and low-to-moderate evenness. The community consisted primarily of δ-Proteobacteria and Firmicutes, bacteria that are recognized to be capable of exocellular electron transfer.
Electrochemical Behavior of Ni-based Alloys for Hydrogen Evolution Reaction in Alkaline Media
Authors: Vazquez-Nava Liliana , Patlán-Olmedo Karina , Oliver-Tolentino Miguel A. , Gonzalez-Huerta Rosa , Dorantes-Rosales Hector J. , Guzmán-Vargas Ariel , Manzo-Robledo Arturo
Published: August 2018

*Nickel-based alloys (Ni0.8CoO0.1Zn0.05MnO0.02Ti0.01Y0.01Al0.01(M1), NiO0.8CoO0.1Zn0.05MnO0.02Ti0.01Y0.01Al0.01 (M2) and NiO0.6CoO0.35Zn0.025Ti0.025 (M3)) were synthesized from high purity powders by means of high-energy mechanical milling. The hydrogen evolution reaction (HER) kinetic-performance of the as-prepared materials was evaluated using linear sweep voltammetry at alkaline conditions and room temperature. According to kinetic parameters calculated from Tafel slopes, the sample M2 showed the better activity in the HER. These results suggest that the electrode surface state in the material play an important role in the proton-adsorption kinetic as demonstrated by SEM, open circuit potential transients and cyclic voltammetry techniques.
A Kinetic-Mechanistic Study of The Hydrogen Evolution Reaction in Sulfuric Acid Solutions with Different Electrode Materials
Authors: Fuentes-Aceituno J.C. , Lapidus G.T.
Published: August 2018

The hydrogen evolution reaction (HER) has been studied extensively due to the potential application of molecular hydrogen H2as a green fuel. Recently this particular reaction attracted the attention of several electrometallurgical researchers because of another promising application, in which the monoatomic hydrogen species H· (intermediate product of HER) is employed as a reducing agent for copper-sulfide minerals. Consequently, knowledge about the kinetics, mechanisms and rate determining step (rds) of HER in sulfuric acid solutions employing aluminum, copper, Inconel® or glassy carbon(GC) cathodes is necessary to determine the under and overpotential domains where H2 and H· can be generated in a selective manner. Analyses of Tafel plots and the charge transfer coefficients, revealed two electrical potential zones for copper, Inconel and GC, where the monoatomic hydrogen can be recombined chemically or electrochemically to H2 as the rds. On the other hand, with aluminum, only the electrochemical recombination to H2 occurs as the rds. A catalytic effect on the hydrogen recombination reaction was also found when ferrous ion is contained in the solution. Finally, it was determined that aluminum is the most efficient electrocatalyst for producing H· and H2, followed by inconel, copper and GC.
Effect of Ultrasound and Electrode Material on Electrochemical Treatment of Industrial Wastewater
Authors: Yaqub Asim , Ajab Huma , Isa Mohamed Hasnain , Jusoh Hisyam , Junaid Muhammad , Farooq Robina
Published: August 2018

The effect of ultrasound (US) and electrode material on electrochemical treatment of industrial wastewater was studied. Samples were taken from three industries i.e. battery, ghee and tannery. Treatment efficiency was monitored by comparing the results of electrochemical and sonoelectrochemical processes in terms of metals and chemical oxygen demand COD removal. Experiments were performed in ultrasonic bath. In sonoelectrochemical process concentration of Pb decreased from 11.5 to 0.6 ppm at 80 kHz form battery industry. Similarly about 95 % removal of Cr (III) was observed from tannery wastewater using lead cathode. Titanium anode was found best counter electrode in metals removing. High COD removal was obtained by using steel anode at 80 kHz. Use of ultrasound is very effective in removing heavy metals and organic pollutants from industrial wastewater.
Electrochemical Behavior of (Zn, Mn)-Al Nitrated Hydrotalcites
Authors: Sampieri Alvaro , Vázquez-Arenas Jorge , González Ignacio , Fetter Geolar , Pfeiffer Heriberto , Villafuerte María-Elena , Bosch Pedro
Published: August 2018

The electrochemical behavior of synthetic binary, Zn-Al and Mn-Al, and ternary (Zn-Mn)-Al hydrotalcites (HT) was studied by cyclic voltammetry in alkaline conditions (pH≡12). The Zn-Al HT characterization revealed two irreversible and continuous oxidation processes: i) Zn0|Zn2+ and ii) Zn0|ZnO. On the other hand, the binary HT containing Mn presented a reversible behavior for the oxidation-reduction process Mn4+|Mn3+. The same oxidation-reduction processes were observed in the ternary HT. However, variations in the reduction-oxidation process were detected by XRD for the ternary HT as a result of spinel formation. These results could also be influenced due to a higher accessibility of manganese in HT since the morphology of hydrotalcite (lamellar structure) provides a regular distribution of Mn atoms interacting with Zn atoms through hydroxyl bridges.
Improved Commercialized Lithium Titanate Performance in Lithium-ion Batteries by Annealing
Authors: Li Xinxi , Zhang Guoqing , Xiong Zhongqiong , Xiong Junqiao , Qiu Yongping
Published: August 2018

Hydrolysis of Al and NaBH4 for hydrogen generation has obtained considerable attention as a portable hydrogen source system. In this paper, we report a new combined hydrogen generation from Al powder and alkaline NaBH4 solution activated by NiCl2 additive. The system is characterized as the followed features: the interaction of Al/NaBH4 hydrolysis, catalytic effect of Ni2B for Al and NaBH4, Al hydrolysis stimulated by NaOH solution. The effects which affect the hydrogen generation performance of the system were studied. The results showed that a favorable combination of high hydrogen yield and high hydrogen generation rate might be obtained via the optimized composition design. Therefore, the system may be developed as a portable hydrogen source system.
Study on Electrochemical Behavior of Ortho-Aminophenol on Nano-Gold/Carbon Nanotubes Composite Modified Electrode
Authors: Wei Yingliang , Wang Anting , Wu Shengbin
Published: August 2018

The aim of this work was to construct a novel modified electrode based on Au nano-particles and carbon nanotube for studying the electrochemical behavior of ortho-aminophenol (OAP). A sensitive oxidation peak of OAP at the potential of 0.352V was observed in HAc-NaAc-PHP buffer solution. The effect factors of the electrochemical response of OAP were optimized by linear sweep voltammetry (LSV). Under the optimum conditions, a linear calibration curve of the peak current of OAP and concentration was obtained in the range of 4.0×10-7~2.0×10-4 mol/L. The oxidation peak current increases direct proportionally with the square root of scanning speed, which indicates that the electrochemical oxidation process of OAP on this modified electrode is diffusion-controlled process. The diffusion coefficient (D) could be estimated and the result was 5.42×10-7 cm2·s-1 by employing chronocoulometry. The charge transfer rate constant (ks) was also discussed and the result was 7.85×10-4 cm·s-1. Concurrently, based on the experiment results, the electrode reaction process of OAP with one electron and one proton was proposed.
The Effect of Binder in Electrode Materials for Capacitance Improvement and EDLC Binder-free Cell Design
Authors: López-Chavéz R. , Cuentas-Gallegos A. K.
Published: August 2018

In the present work we show results related with the influence of the binder type used to elaborate active electrodes made of activated carbon (DLC) for the assembly of supercapacitor cells. A Nafion 5%w solution and/or Kinar Flex (Polyvinylidene fluoride, PVDF) were used as binders at different concentrations, using DLC carbon as the active material to make the electrodes by aerography, and carbon paper as support and current collector. Thickness of the electrodes was controlled by the weight of active material (DLC carbon). Cyclic voltammetry technique was used to investigate the intrinsic capacitive nature of these electrodes, increasing this value from 120 F/g to 245 F/g at 20 mV/s just by improving the type and amount of binder, and the thickness of the electrode. Symmetric 2-electrode cells assembled with binder-free electrodes were electrochemically characterized by galvanostatic cycling, showing capacitance values of 38F/g and a stable behavior during 7000 charge-discharge cycles.
Thermodynamic Analysis of the Absorption Enhanced Autothermal Reforming of Ethanol
Authors: Collins-Martínez Virginia , Bretado Miguel A. Escobedo , Gutiérrez Jesús Salinas , Zaragoza Miguel Meléndez , Guzmán Vanessa. G. , Ortiz Alejandro López
Published: August 2018

Thermodynamic analysis of the absorption enhanced autothermal reforming of ethanol using CaO as CO2 absorbent and O2 in the feed was performed to determine favorable operating conditions to produce a high hydrogen ratio (HR, mols H2-produced/EtOH-feed) and hydrogen concentration in gas product. Steam/Ethanol (S/EtOH) and oxygen/ethanol (O2/EtOH) feed molar ratios were varied in order to find autothermal (?H ? 0) and carbon free operating conditions at 300-900°C and CaO as CO2 absorbent at 1 atm. Carbon formation analysis used S/EtOH = 1.75-2.8, while for hydrogen production varied from stoichiometric; 3:1 to 6.5:1, and O2/ETOH from 0 to 1.0. Results indicate no carbon formation at S/EtOH ? stoichiometric. The absorption enhanced autothermal reforming of ethanol using CaO, O2/EtOH = 0.33, S/EtOH = 6.5 and 600°C, produced an autothermal system with 98% H2 and only a reduction of 9.8% in HR and with respect to the CO2 absorption reforming without O2 feed.
A Kinetic Study of The Hydrogen Evolution Reaction in Phosphoric Acid Solutions with Iron and Manganese Phosphatized Steel Cathodes
Authors: Alvarado-Macías G. , Fuentes-Aceituno J. C. , Salinas-Rodríguez A.
Published: August 2018

In this investigation a kinetic study of the HER was carried out employing a steel rotating disk with different aqueous solutions containing Phosphoric Acid (H3PO4) with or without metallic manganese (Mn) and Nitric Acid (HNO3). Furthermore, the HER was evaluated on iron and manganese phosphate coatings. Analyses of Tafel plots and the charge transfer coefficients, revealed one electrical potential zone where the monoatomic hydrogen can be recombined electrochemically to H2 as the rate determining step, with charge transfer coefficients similar to an activationless process (α→0). On the other hand, an increase in the concentration of H3PO4 promotes a higherexchange current for the HER. The Mn in the aqueous solutions has a catalytic effect on the hydrogen generation rate at room temperature. However, the precipitation of Mn3(PO4)2 on steel decreases the HER kinetics at high temperatures. These observations are also supported with SEM (Scanning Electron Microscopy) characterizations.
Structural, Morphological and Impedance Spectroscopic Analyses of Nano Li(Li0.05Ni0.4Co0.3Mn0.25)O2 Cathode Material Prepared by Sol-Gel Method
Authors: Nichelson A. , Thanikaikarasan S. , Kollu Pratap , Sebastian P. J. , Mahalingam T. , Shajan X. Sahaya
Published: August 2018

In the present work, layered lithium rich Li(Li0.05Ni0.4Co0.3Mn0.25)O2 cathode materials were synthesized and its structural and electrical studies were analyzed. Layered Li(Li0.05Ni0.4Co0.3Mn0.25)O2 cathode material was prepared by sol-gel technique using citric acid as chelating agent. The prepared sample was characterized by X-ray diffraction, SEM-EDS studies. The crystallite size of the Li(Li0.05Ni0.4Co0.3Mn0.25)O2 cathode material was about 57 nm in which the diffusion path of lithium ion is effectively possible. The complexation behavior of prepared cathode material was analyzed by FT-IR spectroscopy. The electrical properties of the prepared Li(Li0.05Ni0.4Co0.3Mn0.25)O2 cathode material was studied by impedance and dielectric spectral analyzes. The maximum ionic conductivity of LiLi0.05Ni0.4Co0.3Mn0.25)O2 was found to be in the order of 10-3.4 S/cm. The dielectric analysis of cathode material confirms the non-Debye type behavior.
Effect of Rare Earth Elements on the Structure and Electrochemical Properties of La0.63R0.2Mg0.17Ni3.1Co0.3 Al0.1 Alloy Electrodes
Authors: Gao Zhijie , Zheng Xiaodong , Du Ping , Luo Yongchun
Published: August 2018

Hydrogen storage alloys La0.63R0.2Mg0.17Ni3.1Co0.3Al0.1 (R = La, Ce, Pr, Nd, Y, Sm, Gd) based on A2B7 type were prepared by induction melting method. The alloys were annealed at 1173K during a week in a sealed stainless steel tube. The structure and the electrochemical properties of the annealed alloys have been studied systematically by XRD, EPMA and electrochemical studies. The alloys structure consists mainly of Ce2Ni7-type (SG: P63/mmc) La2Ni7 phase as well as minor Gd2Co7-type (SG: R-3m) phase, LaNi5 (CaCu5-type, SG:P6/mmm) phase. It is resulted that La0.65Y0.2Mg0.15Ni3.1Co0.3Al0.1 alloy exhibited the maximum electrochemical discharge capacity of 381.2 mAh·g-1. The best cycling stability was obtained with the La0.65Gd0.2Mg0.15Ni3.1Co0.3Al0.1 based alloy. This stability measured as the capacity retention rate at the 100th cycle (S100) was the highest for this sample (92.7%). The variation of the high rate discharge ability with the alloy composition. Its displayed a wave-like change. Firstly it increased from 24.5% (R = La) to 78.4% (R = Ce), then decreased to 14.4 % (R = Sm), and increased again to 63.8% with R = Gd.
Optimization of Parameters and Microstructural Properties of Ba0.5Sr0.5Co0.8Fe0.2O3-δ Thin Films Grown by Pulsed Laser Deposition (PLD)
Authors: Zeljković Saša , Ivas Toni , Infortuna Anna , Gauckler Ludwig J.
Published: August 2018

Ba0.5Sr0.5Co0.8Fe0.2O3 − δ thin films were grown by pulsed laser deposition (PLD) in the temperature range from room temperature (RT) to 1073 K and at oxygen pressures from 6.66 to 39.99 Pa in order to produce dense defect-free thin films. Si with a native oxide layer and MgO were used as the substrate materials. The structure of the thin films was highly dependent on substrate temperature, material and oxygen partial pressure, leading to formation of different microstructures – pores, cracks, columnar and fibrous grains. Cracks and delamination of the thin films were observed in dense layers at higher temperatures, while this was not the case with the columnar thin films. Differences in thermal expansion coefficient, phase transformation and oxygen non-stoichiometry of BSCF are possible explanations for the cracking of the dense thin films. Thin films with a columnar structure are positively influenced by annealing inducing grain growth and densification.
Prickly Nickel Nanowires Grown on Cu-Ni Substrate Surface as High Performance Cathodes for Hydrogen Evolution Reaction
Authors: Shervedani Reza Karimi , Amini Akbar , Karevan Motahareh
Published: August 2018

A new and highly rough nickel electrode is fabricated based on in-situ assembling of prickly nickel nanowires, synthesized by electroless deposition method on a layer of nickel freshly preelectrodeposited on copper, constructing Cu-Ni-PNNWs. Then, the fabricated electrode is studied for Hydrogen Evolution Reaction (HER). Surface morphology of the electrodes is characterized by Field Emission Scanning Electron Microscopy (FESEM) and X-ray diffraction (XRD) microanalysis. Kinetics of the HER is studied in 0.5 M H2SO4 on Cu-Ni-PNNWs electrode in comparison with Ni and Cu-Ni electrodes. Evaluation of the electrode activities is carried out by steady-state polarization curves (Tafel plots) and electrochemical impedance spectroscopy (EIS). The results obtained by electrochemical characterizations have shown that the Cu-Ni-PNNWs electrode benefits of high electrocatalytic activity for the HER. The EIS data are approximated using appropriate equivalent circuit model, and values of the model parameters are extracted. Analysis of the EIS results has revealed that the double layer capacitance (Cdl) and exchange current density (j0) of the Cu-Ni-PNNWs electrode are increased by factors of ~ 47 and ~ 19 times, respectively, compared with Cu-Ni. Up to our knowledge, this is the first finding of this type, reporting synthesis and activity of the Cu-Ni-PNNWs electrode for the HER.
NOx Conversion of Porous LSF15-CGO10 Cell Stacks
Authors: Friedberg A. Z. , Hansen K. Kammer
Published: August 2018

A porous electrochemical reactor, made of La0.85Sr0.15FeO3 as electrode and Ce0.9Gd0.1O1.95 as electrolyte, was studied for the electrochemical reduction of NO with Propene. In order to enhance the effect of polarization, the reactor was impregnated with Ce0.9Gd0.1O1.95, CeO2 or Ce0.8Pr0.2O2-d nanoparticles. The HC-SCR on the cells was increased on the impregnated cells, but no electrochemical enhancement of this was observed. The applied overpotential on the impregnated cells changed the oxidation reaction of NO into NO2 which is considered an intermediate in the NO reduction to nitrogen.
Study on the Interface and Performance of Ti-Al Laminated Composite Electrode Materials
Authors: Han Zhaohui , Zhu Peixian , Guo Yuzhong , Zhou Shenggang
Published: August 2018

The Ti-Al laminated composite materials had been prepared by hot press diffusion bonding in this article, then, treated for different thickness of Al layer in the same process conditions. The change of composite material structure is influences on the performance of Ti-Al were investigated by SEM, HRTEM, electrochemical workstation and so on. The results show that it has the characteristics of the composite's interface and the completion of "metallurgy like" integration between Ti and Al, the chang of matrix structure design of traditional Ti electrode is good for enhance the electrochemical performance of electrode, it is completely changed how the current transfer on the Ti-Al laminated composite materials, so that current distribution of electrode is uniform.
Recent Progress in Structural and Electrochemical Properties in Composite Based LiFePO4 Batteries
Authors: Tabassam Lubna , Tabassam Uzma , Manzoor Umair
Published: August 2018

This review describes some recent developments in the composite doped cathode materials such as LiCoO2, LiNiO2, LiMn2O4, and LiMnO2 with focus on LiFePO4. Olivine LiFePO4 have attracted considerable attention since last decade because of its promising properties as a cathode material in Li ion based batteries (LIBs), that is, it offers high theoretical capacity, environmental friendliness, and less toxicity. The electrochemical and structural characterization of this system will be discussed in more detail as compared with its other counterpart.
Theoretical Insights into the Role of Water Molecule in The Aqueous/Cu(111) Interface during Corrosion Pathway
Authors: Hu Jun , Fan Xiao-yong , Wang Chao-Ming
Published: August 2018

The absorption and possible reaction paths during corrosion have been systematically identified at the molecular level by us-ing density functional theory calculations. The results show that the co-adsorbed water molecule has a two-fold impact on the corrosive kinetics process. The one is the solvation effect, where water molecule affects the various reactions through ion dipole interaction, without bond fracture and formation. Another is the H-transfer mediator, where the bond of co-adsorbed water molecule breaks and regenerates in order to transfer hydrogen atoms.