bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Isothermal Repetitive Upsetting Extrusion on the Microstructure of Mg-12.0Gd-4.5Y-2.0Zn-0.4Zr Alloy
Authors: Zhang Guanshi , Zhang Zhimin , Du Yue , Yan Zhaoming , Che Xin
Published: October 2018

Repetitive upsetting extrusion (RUE) was applied to the as-homogenized Mg-12.0Gd-4.5Y-2Zn-0.4Zr (wt %) alloy at 773 K. The microstructure evolution of the alloy during RUE was investigated. The results indicated that almost all Mg5(Gd,Y,Zn) phases and fine-lamellar long-period stacking-ordered (LPSO) phases were dissolved into the matrix after homogenization treatment at 793 K for 16 h. After one RUE pass, dynamic recrystallization (DRX) occurred. During subsequent RUE passes (from one to three passes), average volume fractions of DRXed grains increased from 43.9% to 65.8%, and that of fine-lamellar and block-shaped LPSO phases gradually decreased. All samples exhibited a typical bimodal microstructure consisting of some initial grains containing fine-lamellar LPSO phases, but consisting mostly of fine-DRXed grains with a mean grain size of 6 μm. Because of an increase in the accumulated strains, the coarse grains were substituted with fine-DRXed grains, the grains were gradually refined, and the microstructure distribution became more homogeneous.
Modification of Asphalt Rubber with Nanoclay towards Enhanced Storage Stability
Authors: Yu Jiangmiao , Ren Zhibin , Yu Huayang , Wang Duanyi , Svetlana Shekhovtsova , Korolev Evgeniy , Gao Zheming , Guo Feng
Published: October 2018

Asphalt rubber (AR), which is prepared by blending crumb rubber and bitumen, provides various advantages, including superior rutting resistance, lower road-tire noise and longer service life. However, contractors have expressed concerns regarding its poor storage stability, which in turn limits its wider application. This study aims to address the storage stability concern by incorporating nano-montmorillonite (nanoclay). Three types of nanoclay were dispersed into hot AR binder by high shear blending. The rheological properties of nanoclay-crumb rubber modifier (CRM)-modified bitumen were evaluated through Superpave performance grade (PG) tests and the storage stability was characterized by measuring the difference in softening points or complex moduli at the top and bottom portions of binders after lab-simulated storage. X-ray diffraction (XRD) evaluation was conducted to observe the variation of nanoclay layer gap distance for mechanism investigation. It was found that all selected nanoclays had insignificant effects on workability, rutting and fatigue properties. The layered nanoclay transformed to intercalated or exfoliated structures after interaction with bitumen fractions, providing superior storage stability. Among the three selected nanoclays, pure montmorillonite with Na+ inorganic group, which has an intermediate hydrophilic property and middle layer gap, showed the most obvious effect on enhancing the storage stability of AR.
Non-Isothermal Crystallization Kinetics of Short Glass Fiber Reinforced Poly (Ether Ether Ketone) Composites
Authors: Yang Xujing , Wu Yazhuo , Wei Kai , Fang Wenjun , Sun Haofei
Published: October 2018

Due to its excellent chemical and temperature resistances, short glass fiber reinforced poly (ether ether ketone) composite (SGF/PEEK) is a promising material for application in automotive lightweight. Processing conditions, such as cooling rate, need to be well controlled to obtain the optimal crystallite morphology of PEEK composites. Thus, in this paper, the non-isothermal crystallization kinetics and melting behavior of SGF/PEEK were investigated by differential scanning calorimetry (DSC) at different cooling rates, and the crystallite sizes were evaluated by the X-ray diffraction technique (XRD). Crystallization kinetics models and effective activation energies were evaluated to determine the crystallization parameters of the composites. The results suggest that a lower cooling rate enlarges the size of crystallites and enhances the uniformity of size distribution. The addition of glass fibers improves the nucleation rate owing to heterogeneous nucleation while decreasing the growth rate due to retarded movement of the polymer chain. The combined Avrami-Ozawa equation was shown to describe accurately the non-isothermal crystallization. The absolute value of the crystallization activation energy for SGF/PEEK is lower than that of pure PEEK.
Effective Elastic Behavior of Irregular Closed-Cell Foams
Authors: Zhu Wenqi , Blal Nawfal , Cunsolo Salvatore , Baillis Dominique , Michaud Paul-Marie
Published: October 2018

This paper focuses on the computational modeling of the effective elastic properties of irregular closed-cell foams. The recent Hill’s lemma periodic computational homogenization approach is used to predict the effective elastic properties. Three-dimensional (3D) rendering is reconstructed with the tomography slices of the real irregular closed-cell foam. Its morphological description is analysed to generate realistic numerical closed-cell structures by the Voronoi-based approach. The influences of the Representative Volume Element (RVE) parameters (i.e., the number of realizations and the volume of RVE) and the relative density on the effective elastic properties are studied. Special emphasis is placed on the appropriate choice of boundary conditions. Satisfying agreements between the homogenized results and the experimental results are observed.
A Reliability-Centered Maintenance Study for an Individual Section-Forming Machine
Authors: Okwuobi Samuel , Ishola Felix , Ajayi Oluseyi , Salawu Enesi , Aworinde Abraham , Olatunji Obafemi , Akinlabi Stephen A.
Published: October 2018

This study investigated the breakdown trend in an automated production with an aim to recommend the application of reliability-centered maintenance (RCM) for improved productivity via a new preventive maintenance (PM) program. An individual section-forming machine (ISM)—a glass blowing machine for making glass bottles—was used as the case study for an automated production system. The machine parts and the working mechanisms were analysed with a special focus on methods of processes and procedures. This will enable the ISM maintenance department to run more effectively and achieve its essential goal of ensuring effective machine operation and reduction in machine downtime. In this work, information is provided on the steps and procedures to identify critical components of the ISM using failure modes and effect analysis (FMEA) as a tool to come up with an optimal and efficient maintenance program using the reliability data of the equipment’s functional components. A relationship between the failure rate of the machine components and the maintenance costs was established such that using the recommended PM program demonstrates evidence of an improvement in the machine’s availability, safety, and cost-effectiveness and will result in an increase in the company’s profit margin.
Analysis of Vibration Plate Cracking Based on Working Stress
Authors: Kang Zeyu , Li Gangjun , Wang Fujun , Zhang Huan , Su Rui
Published: October 2018

At present, vibroseis has become the major technique to achieve environmental protection and high efficiency in fossil fuel exploration. During such exploration, a vibrator transmits seismic waves to the surface. The waves are excited by continuously changing the load stress from the burden of weight of the vehicle and the vibrator’s variable frequency load. This paper will apply a numerical simulation method to develop research on the analysis of vibration plate cracking based on working stress. Based on the structure and mechanism of vibroseis vibrator plate, a vibrator simulation model is built under system dynamics to develop research on the vibroseis plate load stress feature and gain distribution, and change pattern of the plate load stress. The results show that stress response around the upright welding of is high, and there is evident distortion in plate area, which matches the actual fracture position on the plate, and can be confirmed as a key area of plate fatigue.
Managing Human Factors to Reduce Organisational Risk in Industry
Authors: Carpitella Silvia , Carpitella Fortunato , Certa Antonella , Benítez Julio , Izquierdo Joaquín
Published: October 2018

Human factors are intrinsically involved at virtually any level of most industrial/business activities, and may be responsible for several accidents and incidents, if not correctly identified and managed. Focusing on the significance of human behaviour in industry, this article proposes a multi-criteria decision-making (MCDM)-based approach to support organizational risk assessment in industrial environments. The decision-making trial and evaluation laboratory (DEMATEL) method is proposed as a mathematical framework to evaluate mutual relationships within a set of human factors involved in industrial processes, with the aim of highlighting priorities of intervention. A case study related to a manufacturing process of a real-world winery is presented, and the proposed approach is applied to rank human factors resulting from a previous organisational risk evaluation from which suitable inference engines may be developed to better support risk management.
Excavatolide-B Enhances Contextual Memory Retrieval via Repressing the Delayed Rectifier Potassium Current in the Hippocampus
Authors: Huang Irene Y. , Hsu Yu-Luan , Chen Chien-Chang , Chen Mei-Fang , Wen Zhi-Hong , Huang Hsien-Ting , Liu Ingrid Y.
Published: October 2018

Memory retrieval dysfunction is a symptom of schizophrenia, autism spectrum disorder (ASD), and absence epilepsy (AE), as well as an early sign of Alzheimer’s disease. To date, few drugs have been reported to enhance memory retrieval. Here, we found that a coral-derived natural product, excavatolide-B (Exc-B), enhances contextual memory retrieval in both wild-type and Cav3.2−/− mice via repressing the delayed rectifier potassium current, thus lowering the threshold for action potential initiation and enhancing induction of long-term potentiation (LTP). The human CACNA1H gene encodes a T-type calcium channel (Cav3.2), and its mutation is associated with schizophrenia, ASD, and AE, which are all characterized by abnormal memory function. Our previous publication demonstrated that Cav3.2−/− mice exhibit impaired contextual-associated memory retrieval, whilst their retrieval of spatial memory and auditory cued memory remain intact. The effect of Exc-B on enhancing the retrieval of context-associated memory provides a hope for novel drug development.
Seaweed Secondary Metabolites In Vitro and In Vivo Anticancer Activity
Authors: Rocha Djenisa H. A. , Seca Ana M. L. , Pinto Diana C. G. A.
Published: October 2018

Isolation, finding or discovery of novel anticancer agents is very important for cancer treatment, and seaweeds are one of the largest producers of chemically active metabolites with valuable cytotoxic properties, and therefore can be used as new chemotherapeutic agents or source of inspiration to develop new ones. Identification of the more potent and selective anticancer components isolated from brown, green and red seaweeds, as well as studies of their mode of action is very attractive and constitute a small but relevant progress for pharmacological applications. Several researchers have carried out in vitro and in vivo studies in various cell lines and have disclosed the active metabolites among the terpenoids, including carotenoids, polyphenols and alkaloids that can be found in seaweeds. In this review the type of metabolites and their cytotoxic or antiproliferative effects will be discussed additionally their mode of action, structure-activity relationship and selectivity will also be revealed. The diterpene dictyolactone, the sterol cholest-5-en-3β,7α-diol and the halogenated monoterpene halomon are among the reported compounds, the ones that present sub-micromolar cytotoxicity. Additionally, one dimeric sesquiterpene of the cyclolaurane-type, three bromophenols and one halogenated monoterpene should be emphasized because they exhibit half maximal inhibitory concentration (IC50) values between 1–5 µM against several cell lines.
Postponing Pregnancy Through Oocyte Cryopreservation for Social Reasons: Considerations Regarding Clinical Practice and the Socio-Psychological and Bioethical Issues Involved
Authors: Simopoulou Mara , Sfakianoudis Konstantinos , Bakas Panagiotis , Giannelou Polina , Papapetrou Christina , Kalampokas Theodoros , Rapani Anna , Chatzaki Ekaterini , Lambropoulou Maria , Lourida Chrysoula , Deligeoroglou Efthymios , Pantos Konstantinos , Koutsilieris Michael
Published: October 2018

Oocyte freezing for ‘social reasons’ refers to women of reproductive age who are aiming to prolong, protect and secure their fertility. The term emerged to describe application of the highly promising technique, namely vitrification on oocytes retrieved through controlled ovarian stimulation (COS) from women intending to preserve their fertility for social reasons. These women opt to cryopreserve their oocytes at a point in their life when they need to postpone childbearing on the grounds of so called ‘social’ reasons. These reasons may include a highly driven career, absence of an adequate partner, financial instability, or personal reasons that make them feel unprepared for motherhood. This is a sensitive and multifaceted issue that entails medical, bioethical and socio-psychological components. The latest trend and the apparent increase noted on oocyte freezing for ‘social reasons’ has prompted our team of fertility specialists, embryologists, obstetricians, gynecologists and psychologists to proceed with a thorough, critical and all-inclusive comprehensive analysis. The wide range of findings of this analysis involve concerns of embryology and epigenetics that shape decisions made in the IVF laboratory, issues regarding obstetric and perinatal concerns on the pregnancy concluding from these oocytes and the respective delivery management and neonatal data, to the social and bioethical impact of this trend’s application. This literature review refers to matters rising from the moment the ‘idea’ of this option is ‘birthed’ in a woman’s thoughts, to proceeding and executing it clinically, up until the point of the pediatric follow up of the children born. We aim to shed light to the controversial issue of oocyte freezing, while objectively exhibit all aspects regarding this complex matter, as well as to respectfully approach how could the prospect of our future expectations be shaped from the impact of its application.
Superior Mechanical Properties and Work-Hardening Ability of Ultrafine-Grained Quenched and Partitioned Steels Processed by a Novel Approach Involving Asymmetric Hot Rolling
Authors: Tang Zhengyou , Huang Jianeng , Lu Xingchao , Ding Hua , Zhang Dongmei , Misra Devesh
Published: October 2018

An approach is proposed to enhance the mechanical properties and work-hardening (WH) ability of low-alloy steels. Using asymmetric hot rolling (AHR) and subsequent direct quenching (DQ) prior to the quenching and partitioning (Q&P) process, an ultrafine-grained Q&P steel with excellent combination of tensile strength of ~1000 MPa and total elongation of ~35% was obtained, which exhibited high WH exponent at higher strain induced by the higher volume fraction and higher stability of film-like retained austenite located between the martensite laths.
Behaviour of Steel Grade S275JR Columns under the Influence of High-Temperature Creep
Authors: Torić Neno , Boko Ivica , Divić Vladimir , Burgess Ian W.
Published: October 2018

This paper presents a test study focused on determining the influence of high-temperature creep on the buckling of grade S275JR columns. Both capacity and stationary-creep column tests were performed within the study. The results obtained demonstrate that high-temperature creep influences a column’s load-bearing capacity, even at 400 °C if the column’s load ratio is above 87%. The reduction of load capacity due to creep was determined experimentally up to 600 °C, for which the failure due to creep occurred at load ratios above 57% of the capacity at 600 °C. The failure times for all the column creep tests occurred within 240 min of loading at constant temperature. Numerical modelling of the creep tests, including their constant-temperature capacity, was performed with the help of the research software Vulcan, by explicitly including a previously developed creep model for grade S275JR steel in the total strain formulation.
Accelerating Flux Calculations Using Sparse Sampling
Authors: Gnam Lukas , Manstetten Paul , Hössinger Andreas , Selberherr Siegfried , Weinbub Josef
Published: October 2018

The ongoing miniaturization in electronics poses various challenges in the designing of modern devices and also in the development and optimization of the corresponding fabrication processes. Computer simulations offer a cost- and time-saving possibility to investigate and optimize these fabrication processes. However, modern device designs require complex three-dimensional shapes, which significantly increases the computational complexity. For instance, in high-resolution topography simulations of etching and deposition, the evaluation of the particle flux on the substrate surface has to be re-evaluated in each timestep. This re-evaluation dominates the overall runtime of a simulation. To overcome this bottleneck, we introduce a method to enhance the performance of the re-evaluation step by calculating the particle flux only on a subset of the surface elements. This subset is selected using an advanced multi-material iterative partitioning scheme, taking local flux differences as well as geometrical variations into account. We show the applicability of our approach using an etching simulation of a dielectric layer embedded in a multi-material stack. We obtain speedups ranging from 1.8 to 8.0, with surface deviations being below two grid cells (0.6–3% of the size of the etched feature) for all tested configurations, both underlining the feasibility of our approach.
Zircon Macrocrysts from the Drybones Bay Kimberlite Pipe (Northwest Territories, Canada): A High-Resolution Trace Element and Geochronological Study
Authors: Reguir Ekaterina P. , Chakhmouradian Anton R. , Elliott Barrett , Sheng Ankar R. , Yang Panseok
Published: October 2018

Zircon macrocrysts in (sub)volcanic silica-undersaturated rocks are an important source of information about mantle processes and their relative timing with respect to magmatism. The present work describes variations in trace element (Sc, Ti, Y, Nb, lanthanides, Hf, Ta, Pb, Th, and U) and isotopic (U-Pb) composition of zircon from the Drybones Bay kimberlite, Northwest Territories, Canada. These data were acquired at a spatial resolution of ≤100 µm and correlated to the internal characteristics of macrocrysts (imaged using cathodoluminescence, CL). Six types of zircon were distinguished on the basis of its luminescence characteristics, with the majority of grains exhibiting more than one type of CL response. The oscillatory-zoned core and growth sectors of Drybones Bay zircon show consistent variations in rare-earth elements (REE), Hf, Th, and U. Their chondrite-normalized REE patterns are typical of macrocrystic zircon and exhibit extreme enrichment in heavy lanthanides and a positive Ce anomaly. Their Ti content decreases slightly from the core into growth sectors, but the Ti-in-zircon thermometry gives overlapping average crystallization temperatures (820 ± 26 °C to 781 ± 19 °C, respectively). There is no trace element or CL evidence for Pb loss or other forms of chemical re-equilibration. All distinct zircon types are concordant and give a U-Pb age of 445.6 ± 0.8 Ma. We interpret the examined macrocrysts as products of interaction between a shallow (<100 km) mantle source and transient kimberlitic melt.
An Improved High-Pressure Roll Crusher Model for Tungsten and Tantalum Ores
Authors: Anticoi Hernan , Guasch Eduard , Ahmad Hamid Sarbast , Oliva Josep , Alfonso Pura , Bascompta Marc , Sanmiquel Lluis , Escobet Teresa , Escobet Antoni , Parcerisa David , Peña-Pitarch Esteban , Argelaguet Rosa , De Felipe Jose Juan
Published: October 2018

An improved approach is presented to model the product particle size distribution resulting from grinding in high-pressure roll crusher with the aim to be used in standard high-pressure grinding rolls (HPGR). This approach uses different breakage distribution function parameter values for a single particle compression condition and a bed compression condition. Two materials were used for the experiments; altered Ta-bearing granite and a calc-silicate tungsten ore. A set of experiments was performed with constant operative conditions, while varying a selected condition to study the influence of the equipment set-up on the model. The material was comminuted using a previously determined specific pressing force, varying the feed particle size, roll speed and the static gap. A fourth group of experiments were performed varying the specific pressing force. Experimental results show the high performance of the comminution in a high-pressure environment. The static gap was the key in order to control the product particle size. A mathematical approach to predict the product particle size distribution is presented and it showed a good fit when compared to experimental data. This is the case when a narrow particle size fraction feed is used, but the fit became remarkably good with a multi-size feed distribution. However, when varying the specific pressing force in the case of the calc-silicate material, the results were not completely accurate. The hypothesis of simultaneous single particle compression and bed compression for different size ranges and with different parameters of the distribution function was probed and reinforced by various simulations that exchanged bed compression parameters over the single particle compression distribution function, and vice versa.
Nano Precipitates Formed during the Dissolution of Calcite Incorporated with Cu and Mn
Authors: Zhang Xiaohang , Wu Shijun , Chen Fanrong
Published: October 2018

Calcite is often doped with impurity ions that affect its dissolution behavior. In the present investigation, solid solutions of (Ca, Mn)CO3 and (Ca, Cu)CO3 were synthesized by coprecipitation to study their dissolution in an acidic solution (pH = 5) at 25 °C. The solution chemical analysis results showed that the concentrations of aqueous Cu2+ and Mn2+ first increased and then decreased with the extension of dissolution time. Scanning electron microscope (SEM) and transmission electron microscope (TEM) observations revealed that rhodochrosite (MnCO3) and malachite (Cu2(OH)2CO3) formed during the dissolution. This suggested that the impurities in calcite might impact the dissolution and precipitation of carbonates in the environment.
Integrated Geochemical and Morphological Data Provide Insights into the Genesis of Ferromanganese Nodules
Authors: Benites Mariana , Millo Christian , Hein James , Nath Bejugam , Murton Bramley , Galante Douglas , Jovane Luigi
Published: October 2018

Ferromanganese nodules grow by precipitation of metals from seawater and/or sediment pore water. The formation of different genetic types depends on the composition and redox conditions of the water and upper sediment layers, water depth, and primary productivity in surface waters. Many characteristics of nodules have been used to investigate their genesis. In this paper, we compare nodules from different environments using Computed Tomography, Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy, and Micro X-ray Fluorescence data to better understand how geochemical differences are linked to different morphological features. We use representative samples of purely hydrogenetic nodules and mixed-type nodules with various proportions of hydrogenetic and diagenetic growth laminae. Our results show a micrometric alternation between high-absorbance massive Mn-enriched (Mn/Fe up to 40) laminae and low-absorbance dendritic Mn-depleted (Mn/Fe about 1) laminae in mixed-type nodules, suggesting the rhythmic alternation of hydrogenetic oxic conditions and suboxic diagenetic input. This micro-rhythmic alternation is absent in purely hydrogenetic nodules, which are homogenous both chemically and morphologically. A conceptual model is proposed to account for these geochemical and morphological differences in terms of the vertical migration of the oxic-suboxic front relative to the base of the nodules.
The Influence of Vacuum Impregnation on Nutritional Properties of Fluidized Bed Dried Kale (Brassica oleracea L. Var. Acephala) Leaves
Authors: Pasławska Marta , Nawirska-Olszańska Agnieszka , Stępień Bogdan , Klim Angelika
Published: October 2018

The aim of the work was to assess the possibility of obtaining high bioactivity dried kale using a vacuum impregnation as the preliminary processing before the drying. Kale leaves underwent vacuum impregnation in freshly squeezed onion juice and in sodium chloride solution utilising the following impregnation process parameters: At the vacuum stage, 6 kPa reduced pressure for 1 min, dosing the impregnating solution and keeping the sample under vacuum for 2 min, and then 6 min in impregnating solution at atmospheric pressure. Fluidized bed drying of kale was conducted using inert polypropylene balls, utilising a drying air temperature in a range from 70 to 130 °C. The drying kinetics were described, and the dehydrated product’s quality was assessed, on the basis of these selected characteristics: The content of chlorophylls, polyphenols and carotenoids, and antioxidant activity measured with ABTS+, dry matter, water activity and colour. It was determined that protective influence of vacuum impregnation before fluidized bed drying was seen only in the case of using temperatures of 90 and 110 °C. The highest content of bioactive components in dried kale was obtained in the case of using onion juice impregnation and drying at 110 °C.
Photophysical Properties of Nitrated and Halogenated Phosphorus Tritolylcorrole Complexes: Insights from Theory
Authors: Alberto Marta Erminia , De Simone Bruna Clara , Mazzone Gloria , Russo Nino , Toscano Marirosa
Published: October 2018

The photophysical properties of a series of nitrated and halogenated phosphorus tritolylcorrole complexes were studied in dichloromethane solvent by using the density functional theory. Particular emphasis was given to the absorption spectra, the energy gap between the excited singlet and triplet states, and the magnitude of the spin-orbit couplings for a series of possible intersystem crossing channels between those excited states. The proposed study provides a better description of the photophysical properties of these systems while giving insights into their possible use as photosensitizers in photodynamic therapy.
Exotic Spectra and Lattice Vibrations of Ice X Using the DFT Method
Authors: Jiang Lu , Yao Shu-Kai , Zhang Kai , Wang Ze-Ren , Luo Hui-Wen , Zhu Xu-Liang , Gu Yue , Zhang Peng
Published: October 2018

A typical vibrational spectrum in the ice phase has four separate bands: Translation, libration, bending, and stretching. Ice X, the final ice phase under high pressure, shows an exotic vibrational spectrum. Based on harmonic approximation, an ideal crystal of ice X has one peak, at 998 cm−1, for Raman scattering and two peaks, at 450 cm−1 and 1507 cm−1, for infrared absorption in this work. These three characteristic peaks are indicators of the phase transition between ice VII and VIII and ice X. Despite many experimental and theoretical works on ice X, only this study has clearly indicated these characteristic peaks in the region of the IR band. The phonon density of states shows quite different features than ice VIII, which could be verified by inelastic neutron scattering in the future. The dynamic processes of 15 vibrational normal modes are discussed and the typical hydrogen bonds are missing.
“There Was No Green Tick”: Discovering the Functions of a Widget in a Joint Problem-Solving Activity and the Consequences for the Participants’ Discovering Process
Authors: Sunnen Patrick , Arend Béatrice , Maquil Valérie
Published: October 2018

In recent years, tangible user interfaces (TUI) have gained in popularity in educational contexts, among others to implement problem-solving and discovery learning science activities. In the context of an interdisciplinary and cross-institutional collaboration, we conducted a multimodal EMCA-based video user study involving a TUI-mediated bicycle mechanics simulation. This article focusses on the discovering work of a group of three students with regard to a particular tangible object (a red button), designed to support participants engagement with the underlying physics aspects and its consequences with regard to their engagement with the targeted mechanics aspects.
Magnetic Au-Ag-γ-Fe2O3/rGO Nanocomposites as an Efficient Catalyst for the Reduction of 4-Nitrophenol
Authors: Lei Guangyu , Ma Jingwen , Li Zhen , Fan Xiaobin , Peng Wenchao , Zhang Guoliang , Zhang Fengbao , Li Yang
Published: October 2018

In this paper, a facile route has been developed to prepare magnetic trimetallic Au-Ag-γ-Fe2O3/rGO nanocomposites. The impact of the preparation method (the intensity of reductant) on the catalytic performance was investigated. The nanocomposites were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The prepared nanocomposites show fine catalytic activity towards the reduction reaction of 4-nitrophenol (4-NP). The nanocomposites also have superparamagnetism at room temperature, which can be easily separated from the reaction systems by applying an external magnetic field.
Chronoamperometric Observation and Analysis of Electrocatalytic Ability of Single Pd Nanoparticle for Hydrogen Peroxide Reduction Reaction
Authors: Park June Young , Kim Ki Jun , Son Hyeryeon , Kwon Seong Jung
Published: October 2018

The current generated by the collision of a single nanoparticle (NP) of palladium (Pd) on a gold (Au) ultramicroelectrode (UME) surface was observed using an electrocatalytic amplification method. The hydrogen peroxide reduction reaction was used for the electrocatalytic reaction because the hydrogen peroxide reduction reaction has no gas-phase product, which would induce rapid signal decay. The electrocatalytic current resulting from a single Pd nanoparticle on the Au UME shows a staircase response with accompanying slow current decay. The applying potential and concentration of hydrogen peroxide were optimized for clear distinction of signal. The height of the current step and signal frequency were analyzed and compared with the theoretical expectation. The analysis of the electrocatalytic activity of single Pd NPs provides insight toward their future application.
Targeted Nanomedicine to Treat Bone Metastasis
Authors: Adjei Isaac M. , Temples Madison N. , Brown Shannon B. , Sharma Blanka
Published: October 2018

Bone metastases are common complications of solid tumors, particularly those of the prostate, breast, and lungs. Bone metastases can lead to painful and devastating skeletal-related events (SREs), such as pathological fractures and nerve compressions. Despite advances in treatment for cancers in general, options for bone metastases remain inadequate and generally palliative. Anticancer drugs (chemotherapy and radiopharmaceuticals) do not achieve therapeutic concentrations in the bone and are associated with dose-limiting side effects to healthy tissues. Nanomedicines, with their tunable characteristics, have the potential to improve drug targeting to bone metastases while decreasing side effects for their effective treatment. In this review, we present the current state of the art for nanomedicines to treat bone metastases. We also discuss new treatment modalities enhanced by nanomedicine and their effects on SREs and disease progression.
Investigations Concerning the Residence Time Distribution of Twin-Screw-Extrusion Processes as Indicator for Inherent Mixing
Authors: Wesholowski Jens , Berghaus Andreas , Thommes Markus
Published: October 2018

Over recent years Twin-Screw-Extrusion (TSE) has been established as a platform technology for pharmaceutical manufacturing. Compared to other continuous operation, one of the major benefits of this method is the combination of several unit operations within one apparatus. Several of these are linked to the Residence Time Distribution (RTD), which is typically expressed by the residence time density function. One relevant aspect for pharmaceutical processes is the mixing capacity, which is represented by the width of this distribution. In the frame of this study the influence of the mass flow, the temperature and the screw-barrel clearance were investigated for a constant barrel load (specific feed load, SFL). While the total mass flow as well as the external screw diameter affected the mixing performance, the barrel temperature had no influence for the investigated range. The determined results were additionally evaluated with respect to a fit to the Twin-Dispersion-Model (TDM). This model is based on the superimposition of two mixing functions. The correlations between varied process parameters and the obtained characteristic model parameters proved this general physical view on extrusion.
A Highly Sensitive, Polarization Maintaining Photonic Crystal Fiber Sensor Operating in the THz Regime
Authors: Rana Sohel , Kandadai Nirmala , Subbaraman Harish
Published: October 2018

In this paper, a high sensitivity, polarization preserving photonic crystal fiber (PCF), based on circular air holes for sensing in the terahertz (THz) band, is presented. The finite element method, a practical and precise computational technique for describing the interactions between light and matter, is used to compute the modal properties of the designed fiber. For the designed PCF, comprising of circular air holes in both the cladding and in the porous core, a relative sensitivity of 73.5% and a high birefringence of 0.013 are achieved at 1.6 THz. The all circular air-hole structure, owing to its simplicity and compatibility with the current fiber draw technique for PCF fabrication, can be realized practically. It is anticipated that the designed fiber can be employed in applications such as detection of biological samples and toxic chemicals, imaging, and spectroscopy.
Investigation on the Short-Term Aging-Resistance of Thermoplastic Polyurethane-Modified Asphalt Binders
Authors: Yu Ruien , Zhu Xijing , Zhang Maorong , Fang Changqing
Published: October 2018

In this reported work, thermoplastic polyurethane (TPU) was used as a reactive polymer modifying agent to prepare a modified-asphalt, using a high-speed shearing method. Physical performance tests of the TPU-modified asphalt were conducted before and after short-term aging, and the aging resistance was examined by the change in materials properties. In addition, low-temperature rheological properties, thermal properties, the high-temperature storage stability, and the aging mechanism of TPU-modified asphalt were also investigated. The results showed that the addition of TPU improved the aging resistance of base asphalt, which was evidenced by the increased penetration ratio and decreased softening point of the asphalt, after aging. Similarly, Fourier Transform infrared (FTIR) spectroscopy results verified that TPU improved the asphalt aging resistance. It was found that the TPU functional groups played a role in improving thermal properties, high-temperature storage stability, and in the dispersion of modified asphalt.
Effect of Different Types of Electrospun Polyamide 6 Nanofibres on the Mechanical Properties of Carbon Fibre/Epoxy Composites
Authors: Monteserín Cristina , Blanco Miren , Murillo Nieves , Pérez-Márquez Ana , Maudes Jon , Gayoso Jorge , Laza Jose Manuel , Aranzabe Estíbaliz , Vilas Jose Luis
Published: October 2018

Delamination and brittle matrix fracture have long since been the biggest problems in fibre-reinforced composites. Recently, the incorporation of electrospun nanofibre veils has been shown to be an effective method for improving the mechanical properties of these composites, without causing process problems and negatively affecting other mechanical properties. Thus, these nanofibres have the potential to be used as thickness-reinforcing materials in composites. This paper investigates the effect of incorporating standalone electrospun nanofibre veils made of two different types of polyamide 6 (PA6) on the mechanical properties of carbon fibre/epoxy composites. The influence of positioning the electrospun veils at different interlaminar positions of the laminate has also been investigated.
A Redox Conjugated Polymer-Based All-Solid-State Reference Electrode
Authors: Qu Ke , Fang Mingxi , Zhang Shuwei , Liu Haiying , Zeng Xiangqun
Published: October 2018

This work reports the design, synthesis, and characterization of a novel redox-active conjugated polyaniline containing quinone moiety as a solid state reference electrode. The union of electro-active quinone with π-conjugated polyaniline was created by the first chemical synthesis of para-dimethoxybenzene-functionalized aniline as a monomer using a palladium-mediated coupling. The successful polymerization of the as-prepared monomer was accomplished without acid additives. Its post-polymerization modification with strong Lewis acid boron tribromide furnished unique poly (aniline quinone/hydroquinone) with desired properties for all-solid-state reference electrode (RE) applications. The electrochemical responses from the conjugated polyaniline backbone in this unique polymer have been “suppressed” by the quinone pendant. The resulting poly (aniline quinone) showed a quasi-reversible redox process from the redox behavior of the pendant quinone. The stable electrode potential of this poly (aniline quinone/hydroquinone) suggested that it was a single phase in which the amounts of totally reduced and totally oxidized species could be maintained at a constant in various solvents and electrolytes. Its electrochemical stability was excellent with 95% peak current retention after continuous cyclic voltammetric testing. The aniline and quinone moieties in poly (aniline quinone/hydroquinone) render it to have both hydrophilic and hydrophobic compatibility. It showed excellent behavior as a reference electrode in aqueous and non-aqueous media and can be used in both non-zero current and zero-current conditions, providing a stable potential with a maximum potential drift of ~4.7 mV over ten consecutive days.
A Polymer-Gel Eye-Phantom for 3D Fluorescent Imaging of Millimetre Radiation Beams
Authors: Luthjens Leonard H. , Yao Tiantian , Warman John M.
Published: October 2018

We have filled a 24 mm diameter glass sphere with a transparent polymer-gel that is radio-fluorogenic, i.e., it becomes (permanently) fluorescent when irradiated, with an intensity proportional to the local dose deposited. The gel consists of >99.9% tertiary-butyl acrylate (TBA), pre-polymerized to ~15% conversion, and ~100 ppm maleimido-pyrene (MPy). Its dimensions and physical properties are close to those of the vitreous body of the human eye. We have irradiated the gel with a 3 mm diameter, 200 kVp X-ray beam with a dose rate of ~1 Gy/min. A three-dimensional (3D) (video) view of the beam within the gel has been constructed from tomographic images obtained by scanning the sample through a thin sheet of UV light. To minimize optical artefacts, the cell was immersed in a square tank containing a refractive-index-matching medium. The 20–80% penumbra of the beam was determined to be ~0.4 mm. This research was a preparatory investigation of the possibility of using this method to monitor the millimetre diameter proton pencil beams used in ocular radiotherapy.
Carbon Nanotube-Based Organic Thermoelectric Materials for Energy Harvesting
Authors: Wang Xiaodong , Wang Hong , Liu Bing
Published: October 2018

Carbon nanotubes (CNTs) have attracted much attention in developing high-performance, low-cost, flexible thermoelectric (TE) materials because of their great electrical and mechanical properties. Theory predicts that one-dimensional semiconductors have natural advantages in TE fields. During the past few decades, remarkable progress has been achieved in both theory and experiments. What is more important is that CNTs have shown desirable features for either n-type or p-type TE properties through specific strategies. Up to now, CNT‒polymer hybrids have held the record for TE performance in organic materials, which means they can potentially be used in high-performance TE applications and flexible electronic devices. In this review, we intend to focus on the intrinsic TE properties of both n-type and p-type CNTs and effective TE enhanced strategies. Furthermore, the current trends for developing CNT-based and CNT‒polymer-based high TE performance organic materials are discussed, followed by an overview of the relevant electronic structure‒TE property relationship. Finally, models for evaluating the TE properties are provided and a few representative samples of CNT‒polymer composites with high TE performance are highlighted.
Acute Pancreatitis as a Complication of Sickle Cell Anaemia
Authors: Moori Parisa L. , Dosis Alexios , Ahmad Zoheb , Kausar Ambareen , Triantafyllopoulou Diana
Published: October 2018

A common cause of abdominal pain is acute pancreatitis, with the majority of cases being attributed to gallstones and excess alcohol. Sickle cell anaemia (SCA) is an autosomal recessive disease causing the production of abnormal haemoglobin. Physiological changes can lead to vaso-occlusion in sickle cell anaemia. Cholelithiasis is frequently seen in patients with SCA and complications from this can increase patient morbidity. We present a rare case of acute pancreatitis inducing a vaso-occlusive crisis.
Absence of Interactions between Denosumab and Warfarin in Women with Osteoporosis
Authors: Polimeni Vincenzo , Sottilotta Gianluca , Branca Fabiola , Mammone Nadia , Panuccio Antonio
Published: October 2018

The monoclonal antibody denosumab reduces bone resorption. Warfarin is an oral anticoagulant used in the prevention and treatment of thrombosis. To date, there have been no studies on the interaction between warfarin and denosumab. The aim of the present study was to assess the maintenance of the Prothrombin Time International Normalized Ratio (INR) in the therapeutic range (TTR) in women under treatment with warfarin and denosumab, in order to evaluate the pharmacological interference of denosumab. No variations of the median TTR were found after undergoing treatment with denosumab: this shows that the intake of denosumab does not require additional checks in anticoagulated patients.
Impacts of Climate and Supraglacial Lakes on the Surface Velocity of Baltoro Glacier from 1992 to 2017
Authors: Wendleder Anna , Friedl Peter , Mayer Christoph
Published: October 2018

The Baltoro Glacier is one of the largest glaciers in the Karakoram mountain range. Long-term monitoring of glacier dynamics provides key information on glacier evolution in a changing climate, which is essential for regional water resource and natural hazard management. On large glaciers, detailed field based mass balance is not feasible. Ice dynamic variations quantify changes in mass transport and possibly the influence of environmental parameters on the evolution of the glacier. Although velocity variations of Baltoro Glacier during winter and summer are linked to seasonally enhanced basal sliding, little is known about differences in timing and magnitude of (intra-)seasonal velocity variations and their determining mechanisms. We present time series of annual, seasonal, and intra-seasonal glacier surface velocities by means of intensity offset tracking applied on multi-mission Synthetic Aperture Radar (SAR) data for a period of 25 years from 1992 to 2017. Supraglacial lakes forming on the downstream glacier surface in summer were mapped from 1991 to 2017 based on the Normalized Difference Water Index (NDWI), calculated from multi-spectral Landsat and ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) imagery. Additionally, precipitation data of the Tropical Rainfall Measurement Mission (TRMM) and temperature data of ERA-Interim were used to derive the Standardized Precipitation Index (SPI) and Standardized Temperature Index (STI) from 1998 to 2017. Linking surface velocities to the SPI confirmed a strong correlation between heavy precipitation events in winter and the magnitude and the timing of glacier acceleration in summer. Downstream extensions of summer acceleration that have been found since 2015 may be explained by additional water draining from an increased number of supraglacial lakes through crevasses that have been formed in consequence of higher initial velocities, evoked by strong winter precipitation. The warmer melt seasons observed in the years 2015 to 2017 additionally affects the formation of a supraglacial lake, so stronger summer acceleration events in recent years may be indirectly related to global warming.
A GEOBIA Approach for Multitemporal Land-Cover and Land-Use Change Analysis in a Tropical Watershed in the Southeastern Amazon
Authors: Souza-Filho Pedro , Nascimento Wilson , Santos Diogo , Weber Eliseu , Silva Renato , Siqueira José
Published: October 2018

The southeastern Amazon region has been intensively occupied by human settlements over the past three decades. To evaluate the effects of human settlements on land-cover and land-use (LCLU) changes over time in the study site, we evaluated multitemporal Landsat images from the years 1984, 1994, 2004, 2013 and Sentinel to the year 2017. Then, we defined the LCLU classes, and a detailed “from-to” change detection approach based on a geographic object-based image analysis (GEOBIA) was employed to determine the trajectories of the LCLU changes. Three land-cover (forest, montane savanna and water bodies) and three land-use types (pasturelands, mining and urban areas) were mapped. The overall accuracies and kappa values of the classification were higher than 0.91 for each of the classified images. Throughout the change detection period, ~47% (19,320 km2) of the forest was preserved mainly within protected areas, while almost 42% (17,398 km2) of the area was converted from forests to pasturelands. An intrinsic connection between the increase in mining activity and the expansion of urban areas also exists. The direct impacts of mining activities were more significant throughout the montane savanna areas. We concluded that the GEOBIA approach adopted in this study combines the advantages of quality human interpretation and the capacities of quantitative computing.