bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of drug susceptibility test for Efinaconazole compared with conventional antifungal agents
Authors: Hur Min Seok , Park Minji , Jung Won Hee , Lee Yang Won
Published: November 2018

Background

Superficial fungal infections are one of the most common and burdensome skin problems affecting quality of life in patients. Various conventional antifungal agents have been used to treat fungal infections; however, various problems have been reported including drug interaction, drug resistance and low effectiveness. Efinaconazole is a novel antifungal agent, which has proven to be particularly effective against onychomycosis compared with conventional antifungal agents. However, the antifungal efficacy of Efinaconazole for specific strains has not been analysed.

Objective

We conducted an in‐vitro study to measure the antifungal activity of Efinaconazole against strains of Trichophyton rubrum, Trichophyton mentagrophytes and Candida albicans compared with widely‐used antifungal drugs.

Methods

We obtained strains of T. rubrum, T. mentagrophytes and C. albicans isolated from patients with onychomycosis and tinea pedis. The minimal inhibitory concentration (MIC) for various strains of fungal species was evaluated for the antifungal susceptibility test.

Results

Efinaconazole showed a low MIC against almost strains of dermatophytes and C albicans and also presented low resistance, indicating high potency of efinaconazole for treatment of superficial fungal infections.

Conclusion

Efinaconazole could be a comparable alternative to replace existing conventional agents.
Arabidopsis HSP70‐16 is required for flower opening under normal or mild heat stress temperatures
Authors: Chen Xu , Shi Lei , Chen Yuqin , Zhu Lu , Zhang Dasheng , Xiao Shi , Aharoni Asaph , Shi Jianxin , Xu Jie
Published: November 2018

Sepals play important roles in protecting inner floral organs from various stresses and in guaranteeing timely flower opening. However, the exact role of sepals in coordinating interior and exterior signals remains elusive. In this study, we functionally characterized a heat shock protein gene, Arabidopsis HSP70‐16, in flower opening and mild heat stress response, using combined genetics with anatomic, physiological, chemical, and molecular analyses. We showed that HSP70‐16 is required for flower opening and mild heat response. Mutation of HSP70‐16 led to a significant reduction in seed setting rate under 22°C, which was more severe at 27°C. Mutation of HSP70‐16 also caused postgenital fusion at overlapping tips of two lateral sepals, leading to failed flower opening, abnormal floral organ formation, and impaired fertilization and seed setting. Chemical and anatomic analyses confirmed specific chemical and morphological changes of cuticle property in mutant lateral sepals, and qRT‐PCR data indicated that expression levels of different sets of cuticle regulatory and biosynthetic genes were altered in mutants grown at both 22°C and 27°C temperatures. This study provides a link between thermal and developmental perception signals and expands the understanding of the roles of sepal in plant development and heat response.
Seed enhancing treatments: comparative analysis of germination characteristics of 23 key herbaceous species used in European restoration programmes
Authors: Lopez del Egido L. , Toorop P. E. , Lanfermeijer F. C.
Published: November 2018

The response of seeds from 23 wild plant species to a range of seed enhancing treatments was studied. We tested the hypothesis that sensitivity of the 23 species to these compounds is related to their ecological niche. The three ecological niches considered were open land, open‐pioneer and woodland. Hence, the germination of a species is likely adapted to different light conditions and other environmental signals related to the niche.

As representatives of environmental signals, the effects of smoke‐related compounds (karrikinolide, KAR1), nitrate and plant growth regulator (gibberellic acid, GA3) on germination were studied. Seeds were exposed to these additives in the imbibition medium; all described as germination cues. We also investigated the effect of light regimes and additives on germination parameters, which included final germination, germination rate and uniformity of germination. Seeds were placed to germinate under three light conditions: constant red light, constant darkness and 12 h white light photoperiod.

We observed inhibition by KAR under light in some species, which may have ecological implications. The results showed that no single treatment increased the germination of all the tested species, rather a wide variation of responsiveness of the different species to the three compounds was found. Additionally, no interaction was found between responsiveness to compounds and ecological niche. However, species in the same ecological niche and dormancy class showed a similar responsiveness to light.

Species that share a similar environment have similar light requirements for germination, while differences exist among species in their responsiveness to other germination cues.
The cotton endocycle‐involved protein SPO11‐3 functions in salt stress via integrating leaf stomatal response, ROS scavenging and root growth
Authors: Wei Zhenzhen , Shi Xinjie , Wei Fang , Fan Zhuxuan , Mei Liqing , Tian Baoming , Shi Yinghui , Cao Gangqiang , Shi Gongyao
Published: November 2018

The SPORULATION 11 (SPO11) proteins are among eukaryotic the topoisomerase VIA (Topo VIA) homologs involved in modulating various important biological processes, such as growth, development and stress response via endoreduplication in plants, but the underlying mechanism response to stress remains largely unknown under salt treatment. Here, we attempted to characterize a homolog of TOP VIA in upland cotton (Gossypium hirsutum L.), designated as GhSPO11‐3. The silencing of GhSPO11‐3 in cotton plants resulted in a dwarf phenotype with a failure of cell endoreduplication and a phase shift in the ploidy levels. The GhSPO11‐3‐silenced plants also showed substantial changes including accumulated malondialdehyde, significantly reduced chlorophyll and proline contents and decreased antioxidative enzyme activity after salt treatment. In addition, transgenic Arabidopsis lines overexpressing GhSPO11‐3 accelerated both leaf and root growth with cell expansion and endopolyploidy. Both leaf stomatal density and aperture were markedly decreased, and the transgenic Arabidopsis lines were more tolerant with expression of stress‐responsive genes under salinity stress. Furthermore, consistent with the reduced reactive oxygen species (ROS), the expression of ROS scavenging‐related genes was largely reinforced, and antioxidant enzyme activities were accordingly significantly enhanced in transgenic Arabidopsis lines under salt stress. In general, these results indicated that GhSPO11‐3 likely respond to salt stress by positively regulating root growth, stomatal response, ROS production and the expression of stress‐related genes to cope with adverse conditions in plants.
Evaluating Potential Distribution of High‐Risk Aquatic Invasive Species in the Water Garden and Aquarium Trade at a Global Scale Based on Current Established Populations
Authors: West Amanda M. , Jarnevich Catherine S. , Young Nicholas E. , Fuller Pam L.
Published: November 2018

Aquatic non‐native invasive species are commonly traded in the worldwide water garden and aquarium markets, and some of these species pose major threats to the economy, the environment, and human health. Understanding the potential suitable habitat for these species at a global scale and at regional scales can inform risk assessments and predict future potential establishment. Typically, global habitat suitability models are fit for freshwater species with only climate variables, which provides little information about suitable terrestrial conditions for aquatic species. Remotely sensed data including topography and land cover data have the potential to improve our understanding of suitable habitat for aquatic species. In this study, we fit species distribution models using five different model algorithms for three non‐native aquatic invasive species with bioclimatic, topographic, and remotely sensed covariates to evaluate potential suitable habitat beyond simple climate matches. The species examined included a frog (Xenopus laevis), toad (Bombina orientalis), and snail (Pomacea spp.). Using a unique modeling approach for each species including background point selection based on known established populations resulted in robust ensemble habitat suitability models. All models for all species had test area under the receiver operating characteristic curve values greater than 0.70 and percent correctly classified values greater than 0.65. Importantly, we employed multivariate environmental similarity surface maps to evaluate potential extrapolation beyond observed conditions when applying models globally. These global models provide necessary forecasts of where these aquatic invasive species have the potential for establishment outside their native range, a key component in risk analyses.
Positive versus negative incentives for loan repayment in microfinance: A game theory approach
Authors: Brihaye Thomas , Pril Julie De , Labie Marc , Périlleux Anaïs
Published: November 2018

In most of the methodologies used so far by microfinance institutions, negative incentives are predominant, which can contrast with these institutions’ social mission. This paper investigates whether the microfinance industry could benefit from using more positive incentives. The main results of our game model are twofold. First, (positive or negative) incentives increase “on‐time” repayments. Second, the client is more likely to repay her loan with the encouragement of a bonus scheme rather than under the pressure of a sanction, regardless of the amount. This paper therefore argues for the increased use of positive incentives in the industry.
Characterization of drought in the Kerio Valley Basin, Kenya using the Standardized Precipitation Evapotranspiration Index: 1960−2016
Authors: Kimosop Peter
Published: November 2018

The Kerio Valley basin in Kenya has undergone several periods of drought, yet drought patterns in the region are not well understood due to limited climatic data. Drought events in the region have resulted in crop failure and livestock deaths, exacerbating food shortages. In this study, the Standardized Precipitation Evapotranspiration Index (SPEI), a multi‐scalar drought index was used to examine the onset, duration, severity, intensity, and frequency of agricultural and hydrological drought in the region. The gridded 0.5° × 0.5° climatic datasets from Climatic Research Unit for the period 1960−2016 was used for analysis. Temporal evolutions of SPEI at 6‐ and 12‐month lags were subsequently used to evaluate agricultural and hydrological drought, respectively. Additionally, the Mann‐Kendall trend test was used to test for trends in the time series. Results from the analysis show that: 1) droughts are becoming more frequent in the region, 2) drought intensities in the arid and semi‐arid lands have weakened, 3) regions west of the Kerio River have recently recorded a wetting trend, and 4) the southern and central regions of the basin are drought‐prone. Understanding the spatial and temporal patterns of drought in the basin can assist in drought preparation and mitigation planning.
Effect of PVP Addition in the Preparation of Polyethersulfone (PES)–AgNO3 Antibacterial Membrane
Authors: Basri H. , Ismail A. F. , Aziz M.
Published: November 2018

Association of antibacterial agent into polymer–based material is an interesting, recent extension in membrane technologies research area. Asymmetric polyethersulfone–silver nitrate (PES–AgNO3) nanocomposite membranes were synthesized by wet phase inversion with polyvinylpyrrolidone (PVP) as additive. Three different molecular weights (MW) of PVP in the range of 10 K to 360 K were tested for their ability to stabilize and disperse silver in the polymer solution. Results showed that PVP 360 K plays a significant role in altering silver particle size with better dispersion compared to the membranes prepared without addition of PVP and with the addition of lower MW of PVP. Results agreed with the leaching detected by ICP–MS where silver loss during membrane fabrication for PES–Ag–P360 is only 0.4636 ppm (0.0093%). The antibacterial activity for the resultant membranes was tested using inhibition zone method. Results indicated that PES–AgNO3 and PES–AgNO3–PVP (loaded with only 0.5 wt% silver) were antibacterial to Escherichia coli and Staphylococcus aureus. The improvement of antibacterial properties of the prepared membranes could be primarily attributed to the PVP addition as well as the surface morphology and permeation properties.
Enhanced Swelling and Barrier Properties Stability of SPEEKbased Polymer Electrolytes Nanocomposite Membran
Authors: Jaafar J. , Ismail A. F. , Matsuura T.
Published: November 2018

The objective of this study is to prepare SPEEK/Cloisite15A®/TAP nanocomposite membranes and to characterize their physicochemical properties as polymeric electrolyte nanocomposites. SPEEK membranes with various degrees of sulfonation (DS) were first prepared. Subsequently, 1 wt. % of Cloisite15A® and 2,4, 6–triaminopyrimidine (TAP), respectively, were introduced into the SPEEK matrices via solution intercalation method. The Cloisite15A® and TAP additives were used as reinforcing material for the SPEEK/Cloisite15A®/TAP (SP/CL/TAP) nanocomposite membranes in terms of the barrier properties, swelling and morphological structure. The effect of DS on the SP/CL/ TAP nanocomposite membranes was studied in terms of their swelling behavior, proton conductivity and methanol permeability. Field emission scanning electron micrographs (FESEM) and X–Ray diffraction (XRD) patterns confirmed that the Cloisite15A® particles were completely distributed to allow the nanosize dispersion in the polymer matrix. The swelling behavior of SPEEK membrane at DS of 88% was improved in the presence of Cloisite15A® and TAP. All SPEEK nanocomposite membranes studied exhibited improved methanol barrier properties compared with the parent SPEEK membranes. Owing to significant conductivity, remarkable barrier properties, high swelling stability and outperformed DMFC performance, SP63/CL/TAP nanocomposite membranes can be considered as a polymer electrolyte membrane for DMFC applications.
The Effect of Silica Loading on the Performance and Morphology of Polyimide–Silica Hybrid Membrane
Authors: Bakar N. S. A. , Hashemifard S. A. , Mustafa A.
Published: November 2018

The performance of silica-polyimide hybrid membranes has been investigated for gas separation processes. The dope solution consisted of polyimide resin dissolved in NMP and silica sols at various weight percentages. The silica sols were prepared using a sol–gel process and the flat–sheet silica–polyimide hybrid membranes were cast using an immersion precipitation technique. The effects of silica sols loading on the gas transport properties of polyimide hybrid membranes and the correlation of morphology changes in the membrane structure and molecular orientation were studied. Polyimide hybrid membranes with silica sols loading ranging from 0 to 50 wt% were tested on gas permeation performance with single gas of O2, N2, CH4 and CO2. The gas permeation results showed that the hybrid membranes with 20 wt% to 25 wt% silica loading exhibited higher selectivity than the pure polyimide membrane. Morphological properties and molecular orientations of the silica–polyimide hybrid membranes were also studied using SEM and FTIR, respectively. The SEM and FTIR results confirmed that the 20 and 25 wt% of silica loading was the ideal composition of polyimide–silica hybrid membrane for gas separation.
Carbon Molecular Sieve Membranes from Polyetherimide: Effect of Pyrolysis Temperature on O2/N2 Selectivity
Authors: Ahmad M. A. , Rashid N. K. A. , Hameed B. H.
Published: November 2018

Carbon molecular sieve (CMS) membranes with excellent separation performance and stability appear to be promising candidate for gas separation. In this work, CMS membranes were formed by a thin carbon layer obtained by pyrolysis of a coated polyetherimide solution onto porous disk support. The pyrolysis temperatures were varied under inert condition. Results showed that the pyrolysis temperature played an important role in determining the gas permeability of CMS membranes. The CMS membrane prepared at pyrolysis temperature of 700°C shows high surface area and narrow PSD with well developed microporous carbon structures. The development of large pore occurs at higher pyrolysis temperature. The O2/N2 permselectivities of 2.86, 2.61 and 2.22, respectively were attained by CMS membranes prepared at pyrolyzed temperature of 700, 800 and 900°C.
Development of Magnetite Nano–composite Membrane for Membrane Defouling
Authors: Azmi N. A. , Ng Q. H. , Ahmad A. L. , Low S. C.
Published: November 2018

This research proposes to untangle the membrane fouling by introducing nanostructured magnetite (Fe3O4) colloids into the polymeric membrane. In present study, nanostructure magnetite nanoparticles (MNPs) were synthesized via co–precipitation method with ammonium hydroxide and sodium hydroxide as the precipitation agents at different pH condition. The synthesized MNPs were functionalized with poly(diallyldimethylammonium chloride) (PDDA) and then spin coated on the surface of the ultrafiltration cellulose acetate (CA) membrane. Intrinsic properties for this nano–composite membrane, in regards to the physical structures, surface negative charge density and the membrane filtration performance, on surface fouling by humic acid solutions were investigated. Experimental results demonstrated that, the nano–composite membrane has significantly reduced the humic acid fouling on the membrane surface. This could be explained by the electrostatic interactions between negatively charged humic acid molecules and the nano–composite membrane. Throughout the study, the results provide some fundamental insights into the physical interactions that governing the membrane fouling during filtration.
Economic Assessment for Cold Sterilization and Clarification of Pineapple Juice and Coconut Water using Microfiltration
Authors: Laorko A. , Tongchitpakdee S. , Youravong W.
Published: November 2018

This study aims to assess the economical feasibility for production of sterilized/clarified pineapple juice and coconut water using cross flow microfiltration (MF). The data for microfiltration plant design is based on the experimental results from our previous studies. The capacity of processing plant for the juice production is assumed to be 20,000 L/day for each juice. The 0.2 m and 0.1 m hollow fiber membranes are used for producing clarified/sterilized pineapple juice and coconut water respectively. The investment cost and the operating cost under various operating conditions are summarized. The operating condition is found to be a major factor influencing capital cost as well as operation cost. The economic assessment is accomplished for production of 5,000 m3/year, yielding an interest rate of return of 38.3-53.6 % and payback period of 1.9-2.6 years for pineapple juice while the yielding an interest rate of return of 19.2-23.2% and payback period of 3.9-4.4 years for coconut water depending on operating conditions.
Effect of Coexisting Natural Organic Matters (NOM) on the Rejection of Endocrine Disrupting Chemicals (EDCs) by A Low Pressure Reverse Osmosis (LPRO) Membrane
Authors: Ozaki Hiroaki , Ikejima Norihito , Matsui Saburo
Published: November 2018

The coexisting natural organic matters (NOM) in the water environment are expected to influence rejections of endocrine disrupting chemicals (EDCs) in membrane filtration. However, such influences and rejection mechanisms are not well understood. This paper aims to elucidate on the rejection of three representative EDCs: Bisphenol A (BPA), 17β–estradiol (E2) and 4–Nonylphenol (NP) by a LPRO membrane (UTC–60) with and without three representative NOM: humic acid (HA), fulvic acid (FA) and effluent organic matters (EfOM) in solutions by laboratory experiments. The EDCs rejections were enhanced with increasing solution pH and negative membrane zeta potential as a result of decreased membrane pore size. Adsorption of the EDCs on membrane surface and size exclusion were the most likely rejection mechanisms in absence of the NOM. Coexistence of the NOM in solutions, in general, enhanced the EDCs rejections. However, no specific trends in rejection were observed possibly due to diffusion of the adsorbed NOM and EDCs molecules through the membrane pores, physicochemical properties of the EDCs and several types of NOM molecules present in EfOM. The EDCs adsorption on NOM molecules and their adsorption on the membrane surface and/or retention by size exclusion were the most likely rejection mechanisms.
ZnO Nanocomposite Membranes for Desalination
Authors: Vijesh A. M. , Liya J. , Shyma P. C.
Published: November 2018

Severe drinking water scarcity is a major problem around the world and pressure driven membrane processes are gaining importance in the field of water purification. This work mainly focuses on improving membrane performance in terms of hydrophilicity, solute rejection, etc. It emphasizes on the preparation of polysulfone (PSf) based blend membranes via phase inversion method. PSf membrane is modified by the addition of zinc oxide (ZnO) nanoparticle at various compositions and the resultant membrane performances were studied. The PSf-ZnO membranes were characterized by ATR-IR and SEM. These membranes showed much better salt rejection performance.
The Effect of the Concentration Polarization and the Membrane Layer Mass Transport on the Membrane Separation
Authors: Nagy Endre , Borbély Gábor
Published: November 2018

The negative effect of the concentration polarization layer on the membrane separation is well known. How the mass transport parameters of the membrane matrix, e.g. the solubility coefficient, membrane Peclet number, can affect the concentration profile of the boundary layer, and consequently, the separation efficiency is not investigated in detail yet. This paper gives the suitable mathematical expressions, in order to predict the well known parameters as polarization modulus, enrichment factors, etc., taking into account the transport parameters for both the concentration boundary and the membrane layers, and analyses the concentration distribution and the polarization modulus. It has been shown that the transport properties of the membrane layer have significant effect on the concentration profiles of the boundary layer and thus, on the polarization modulus, enrichment factors, etc., as well. Thus, the well known equations, e.g. the polarization modulus, enrichment factor given in the literature [see e.g. Equations (2) and (3)], could be considered as approaches.
Hybrid Processes for Extraction–separation of Tocopherols from Crude Palm Oil
Authors: Vachiraanan K. , Rattanapisit J. , Sridang P.
Published: November 2018

The aim of this study was to evaluate the hybrid processes for extraction and separation of tocopherols from crude palm oil. The saponification method was used to extract crude palm oil under various concentrations of alcoholic KOH in the range of 10–60% w/v in a lab scale unit. The experiments were conducted at a temperature and saponification time in the range of 60–80°C and 20–40 min respectively. The performance and efficiency of ultrafiltration were investigated by filtering a fraction of unsponifiables. The results showed that the optimum condition of saponification was 10% alcoholic KOH with the minimum loss of α–tocopherol of around 19%. A lab scale filtration unit with a hydrophobic sheet membrane was operated under a frontal filtration mode at room temperature. The results pointed out that ultrafiltration could remove most of the residual triglycerides and phospholipids contained in unsponifiables at a TMP of 0.25–1.0 bars. The removal of up to 70% of triglycerides and phospholipids was reached when the mixture was ultrafiltered. In addition, these hydride processes present a one of the great option for α–tocopherol purification losing about 5% of yield.
A Study on Improvement of Control Performance of Electric-Continuous Variable Valve Timing System Using BLDC Motor
Authors: Baek Soo-Whang
Published: November 2018

This paper deals with the control performance improvement of the E-CVVT system using BLDC motor. Each element of the E-CVVT system is implemented by mathematical modeling. The response performance of the E-CVVT system is verified based on the camshaft motion, cam profile, BLDC motor and mathematical model of the controller. In order to confirm the speed change of the valve due to the rotation of the camshaft, a cam profile is used to express the up and down motion of the valve as a curve. To analyze the operating characteristics of the E-CVVT system, a BLDC motor is modeled using Simulink. The E-CVVT system controls the phase angle of the camshaft. When the E-CVVT system sets the target phase angle, the motor controller generates the optimal motor speed command. The response speed depends on the setting of each PID parameter, which changes the phase of the camshaft. Finally, we confirmed the improvement of the E-CVVT system response performance according to the change of the PID parameter.
Robust Design Optimization of BLDC Motor for Electric Oil Pump Using Characteristic Function
Authors: Baek Soo-Whang
Published: November 2018

In this paper, we propose and perform the robust design optimization (RDO) algorithm for the shape of the BLDC motor used in the electric oil pump. The proposed RDO algorithm improves the torque characteristics of the BLDC motor to improve the performance of the electric oil pump. The previous deterministic design optimization (DDO) method derives an appropriate combination of the design goal and the specific target performance. However, not only the target performance but also other performance constraints must be considered for RDO. To overcome these problems, we consider the penalty function. In conclusion, we can confirm the improvement of the torque characteristics of the BLDC motor used in the EOP by using the proposed RDO algorithm.
Optical Layout Design for Minimizing Periodical Image Noise in Color Printing System
Authors: Kim Wan-Chin
Published: November 2018

In this study, we present a sync detection optical layout that can reduce the periodic noise of the color printing system. A color printing system which applies tandem type laser scanning unit exposes light onto four photo conductive drums using four laser diodes and a single polygon mirror (PM). In order to reduce the image moire caused by the periodic noise of the shape error of the PM according to the color superposition method, optical analysis on various shape errors of the polygon mirror was performed. In this study, we propose a sync detection layout which can solve the color moire caused by peak-to-valley (PV) shape error of polygonal mirror surface.
Molecular Dynamics Simulation of the Evaporation and Transfer of the Lubricant on a Hard Disk in Heat-Assisted Magnetic Recording
Authors: Haq M. Ashraful , Wang Shao , Ren Zhencheng , Dong Yalin
Published: November 2018

Coarse-grained models were developed to study the evaporation and transfer of the perfluoropolyether lubricant from the disk surface under laser heating. Both moving and stationary disks were simulated with a heat flux applied to a central region under a pad. A novel concept of a reconditioning region was proposed to convert the periodic boundary conditions to more realistic conditions with the fresh material fed at the inlet. The results indicate significant influence of the disk velocity, heat flux and gap distance on the evaporation and transfer of the lubricant. With increasing heat flux, more lubricant molecules tend to reach the slider surface.
Theoretical Study on Features of an Overlap-Type and a Pressing-Type Sheet Separation Mechanisms
Authors: Yoshida Kazushi
Published: November 2018

We examined the behaviors of the paper sheet in an overlap-type sheet separation mechanism and a pressing-type sheet separation mechanism. First, we introduced the models that can calculate the resistance force and feed force acting on the paper sheets in both sheet separation mechanisms. And, based on the calculation results of the resistance force and friction force between the paper sheets, we studied the behavior of the paper sheet in each separation mechanism. As a result, we found that an overlap-type sheet separation mechanism is superior to the pressing-type sheet separation mechanism but it is easily influenced by the feeding force caused by pick-up rollers, and also a pressing-type sheet separation mechanism has robustness for a thickness of paper sheet and for a feeding force caused by pick-up rollers.
Spacing Dependency of Near Field Recording and its Application
Authors: Xiong Shaomin , Smith Robert
Published: November 2018

The head disk spacing in state of the art hard disk drives has been successfully scaled down to a couple of nanometers and is accurately controlled, providing a workable condition for near field devices, such as near field transducers (NFT) and plasmonic sensors. Heat assisted magnetic recording (HAMR) uses an NFT to generate the localized electromagnetic field to heat the media above the Curie temperature. The coupling between the NFT and the magnetic media has a strong spacing dependency, explained by the nature of the evanescent field. In this paper, we discuss how the spacing dependency is accurately calibrated and the applications of this spacing dependency in HAMR, such as static and transient protrusion measurement and compensation and fly height variation measurement.
Groove Shape Optimization of Thrust Air Bearing for Small Size Spindle Considering the Processing Errors
Authors: Ochiai Masayuki , Kato Naoya , Hashimoto Hiromu
Published: November 2018

In this research, we aim to examine the usefulness of the newly developed spindle motor proposed by Ochiai. Since machining error due to tool wear etc. used for microfabrication can be ignored, laser processing was used as a processing method. Thrust bearing grooves were generated by laser processing, and variation in groove depth was observed. Finally, the optimum shape of the thrust bearing groove was obtained by robust optimization using the probability distribution that can be approximated from the obtained machining error.
Optimization of Thin-Film Winding Conditions Considering Viscoelastic Property and Thickness Variation and its Experimental Verification
Authors: Sunami Yuta , Hashimoto Hiromu
Published: November 2018

Plastic films are produced using roll-to-roll systems, which allow the film to be wound into a roll and stored in a small space. Roll defects, however, can cause significant economic loss, and gage bands remain an open area of research. More recently, plastic films have become thinner, so we must now reconsider wrinkling and slippage, problems which depend on the in-roll stress condition. Therefore, predicting the stress condition is essential to preventing defects occurring in wound rolls. In addition, the in-roll stress will change over time as a result of viscoelastic properties. This study theoretically investigates and experimentally verifies winding condition optimization and in-roll stress in consideration of the viscoelastic property and web thickness profile at a constant rewinding tension. Results show that the predicted values are in agreement with the measured values.
Thermo-Molecular Gas-Film Lubrication (t-MGL) Considering Temperature Distributions and Accommodation Coefficients: Analyses by Quasi-Free-Molecular t-MGL Equation
Authors: Fukui Shigehisa , Shinohara Fumiya , Asada Ryota , Matsuoka Hiroshige
Published: November 2018

In the present paper, the flying characteristics of a step slider flying in either air or He with a local temperature distribution of the disk are analyzed using the thermo-molecular gas-film lubrication (t-MGL) equation in the quasi-free-molecular flow region (quasi-free-molecular t-MGL equation: t-MGLqfm eq.). The gas temperature in the t-MGLqfm equation, τG, is assumed to be that in the free molecular limit, τGfm, defined by temperatures and accommodation coefficients at the disk, τW0, α0, and those at the slider, τW1, α1, respectively. The decreases in static spacing for the slider flying in He are significant. Moreover, the spacing decreases as the accommodation coefficients of the disk, α0, decreases, that is, as the ratio of specular reflection increases. The spacing fluctuation caused by a running wavy disk varies according to both the ambient gas (air/He) and the boundary accommodation coefficients.
Magnetic-Assisted Alignment of Reinforcing Functionalized-Fibers in a Composite for Lightweight Structures
Authors: Torres-Sánchez C. , Haghihi-Abayneh M. , Conway P. P.
Published: November 2018

Localized reinforcement of composites employed to manufacture parts for the transport industries is making possible the lightweighting of components that have a much sought-after effect in the reduction of CO2 and NOx emissions. However, its realization, through the removing of mass where it is not required and reinforcement added to areas more prone to stress from working loads, relies on the development of novel manufacturing processes that can create structures whose performance is on a par with their solid counterparts, but at a fraction of the weight and at an affordable production cost.

In this work we exploit the use of a very weak and safe magnetic field to control the location and orientation of functionalized discontinuous carbon fibers within a polymeric structural (polyurethane) foam to create performance-optimized composites.

Two wet-chemistry methods (i.e. in-situ precipitation-deposition and amine-co-adjuvated electrodeposition of magnetite) to transform commercial carbon fiber into a magnetically active form were explored. The resulting fibers were analyzed and characterized through a set of physico-chemical tests. The functionalized fibers were then embedded at 3 different %vol contents in the polymeric matrix at given locations and with a desired alignment. Their mechanical performance (incl. compression, tension) was assessed and benchmarked against both a similar %volumetric content but non-functionalized-reinforcement (i.e. randomly distributed) composites and to non-reinforced matrices. In the two sets of reinforced composites (random and aligned) there is a positive correlation between stiffness, yield strength and strain with increasing %vol content. Both sets outperformed the non-reinforced matrix, demonstrating good fiber adhesion within the matrix and successful load transfer from matrix to fiber. The magnetically aligned composites generally outperformed the non-functionalized ones in terms of stiffness and strength at yield.
A Semi-Analytical Model of Shape-Control in an Adaptive Air Foil Bearing
Authors: Sadri Hossein , Kyriazis Alexander , Schlums Henning , Sinapius Michael
Published: November 2018

The aerodynamic foil bearing is a special type of air bearing in which the flexible foil structure between rotor and rigid housing supports the rotor bearing system with a greater robustness against thermal distortion and production misalignments. In such bearings, the generation of an aerodynamic pressure in the lubricating film after reaching the lift-off speed prevents the solid contact between rotor and foil structure. Since many static and dynamic properties of air foil bearings strongly depend on the inner contour of the bearing, the idea of an adaptive air foil bearing (AAFB) is developed to optimize the bearing’s performance at different operating points. This paper concentrates on a semi-analytical model based on plate theory using Ritz method for simulating the static shape control of piezoelectrically actuatable supporting segments for an AAFB under different loading conditions. The elastic suspension of the supporting segments and symmetries of the bearing are considered in the modeling. After validation by means of FEM analyses and experimental tests the influence of geometry and material is examined in a parametric study. Later on, the model is used for parameter optimization in order to achieve the most effective shape morphing.
Suppression of Cross-Well Oscillations With Active Control of a Bistable Laminate
Authors: Lee Andrew J. , Xie Antai , Inman Daniel J.
Published: November 2018

Although there have been numerous efforts into harnessing the snap through dynamics of bistable structures with piezoelectric transducers to achieve large energy conversion, these same dynamics are undesirable under morphing applications where stationary control of the structure’s configuration is paramount. To suppress cross-well vibrations that primarily result from periodic excitation at low frequencies, a novel control strategy is proposed and implemented on the piezoelectrically generated bistable laminate, which consists of only Macro Fiber Composites (MFC) in a [0MFC/90MFC]T layup. While under cross-well regimes such as chaotic or limit cycle oscillations, a single MFC is actuated past the laminate’s limit voltage to eliminate one of its potential wells and force it into the remaining stable state. Simultaneously, a Positive Position Feedback (PPF) controller suppresses the resulting single-well oscillations through the other MFC. This dual control strategy is demonstrated with an electromechanical model through the suppression of various cross-well regimes, and results in significant reduction of amplitude. The active control capability of the laminate prevents snap through instability when under large enough external vibrations and adds to its multifunctionality along with morphing and broadband energy harvesting.
Passive Adaptive Wave Manipulation Using Nonlinear Acoustic Metamaterials
Authors: Valappil Sabiju Valiya , Sheehan Catherine , Manimala James Mathew
Published: November 2018

Acoustic metamaterials display unusual mechanical wave manipulation behavior not seen in natural materials. In this study, nonlinear metamaterials with passive, amplitude-activated directional bandgaps are investigated. Test articles are constructed by installing periodic arrays of mass-loaded dome resonators on a square polycarbonate substrate. These resonators display nonlinear softening response with increase in excitation amplitude. Experiments conducted by mounting the test articles on low-stiffness boundaries along two adjacent sides and applying mechanical excitations at the opposite corner. A mechanically-staged laser vibrometer mounted overhead was used to make noncontact measurements at discrete plate and resonator locations. Measured displacement transmissibility verify the existence and extent of bandgap frequency ranges as well as amplitude-activated shifts in their bounds. Moreover, by tailoring the pattern of resonators within the array, preferential steering, focusing and selective beaming of waves within tunable frequency ranges depending on their amplitude are shown to be possible. Steady-state spatial maps depicting the displacement transmissibility field were generated from experiments and correlated with simulations to bring out underlying mechanisms. In addition, both lumped parameter and continuum models are considered to aid the design of scalable, passive adaptive metamaterial waveguides for applications ranging from seismic wave mitigation to MEMS transduction.
Feasibility Research on Coupled Friction/Piezoelectric Dampers
Authors: Li Lin , Wu Yaguang , Fan Yu
Published: November 2018

A new passive damper coupling the energy dissipative mechanisms of dry friction and piezoelectric shunting circuit is proposed. The idea is to embed the shunted piezoelectric materials to the dry friction dampers at appropriate positions, so that the elastic deformation of the dry friction dampers can be utilized to generate additional damping. Moreover, this provides a more practical way to install the piezoelectric dampers into realistic mechanical systems such as aero-engines. A five Degree-of-freedom (DOFs) lumped system model is introduced to demonstrate the feasibility of such an idea. The damping performance is revealed using the forced response results obtained by the Multi Harmonic Balance Method (MHBM). We show that the coupled damper significantly outperforms the standalone piezoelectric or dry friction dampers. The coupled damper is better than, at least equivalent to, the case where both piezoelectric and dry friction dampers are applied but in uncoupled manner. Eventually, the mechanism of the proposed damper is further explained from the perspective of vibrational mode and energy conversion.
Design of an Adaptive Twist Trailing Edge for Large Commercial Aircraft Applications
Authors: Rea Francesco , Amoroso Francesco , Pecora Rosario , Kintscher Markus
Published: November 2018

Researchers and engineers design modern aircraft wings to reach high levels of efficiency with the main outcome of weight saving and airplane lift-to-drag ratio increasing. Future commercial aircraft need to be mission-adaptive to improve their operational efficiency. Twistable trailing edge could be used to improve aircraft performances during climb and off-design cruise conditions in response to variations in speed, altitude, air temperature, and other flight parameters. Indeed, “continuous” span-wise twist of the wing trailing edge could provide significant reduction of the wing root bending moment through redistribution of the aerodynamic load leading to an increase of the payload/structural weight ratio. Within the framework of the Clean Sky 2 (CS2) European research project, the authors focused on the preliminary design of a full-scale composite multifunctional tab retrofitting the outboard morphing Fowler flap of a turboprop regional aircraft. The investigation domain of the novel device is equal to 5.15 meters in span-wise direction and 10% of the local wing chord.

The structural and kinematic design process of the actuation system is completely addressed: two rotary electromechanical motors, placed in the root and tip flap sections, are required to activate the inner mechanisms enabling delta twist angles up to 10 degrees along the outboard region when the flap is stowed in the wing. The structural layout of the thin-walled closed-section composite tab represents a promising concept to balance the conflicting requirements between load-carrying capability and shape adaptivity in morphing lightweight structures. The main design parameters are optimized to minimize actuation torque required for twisting while providing proper flexural rigidity to withstand limit aerodynamic pressure distributions for large airplanes. Finally, the embedded system functionality of the actuation system coupled with the composite wing trailing edge is fully investigated by means of detailed finite element simulations. Results of actuation system performances, and aeroelastic deformations considering operative aerodynamic loads demonstrate the potential of the proposed structural concept to be energy efficient, and lightweight for real aircraft implementation.
3D-Printed Stretchable Strain Sensor With Application to Wind Sensing
Authors: Al-Rubaiai Mohammed , Tsuruta Ryohei , Gandhi Umesh , Wang Chuan , Tan Xiaobo
Published: November 2018

Stretchable strain sensors with large strain range, high sensitivity, and excellent reliability are of great interest for applications in soft robotics, wearable devices, and structure-monitoring systems. Unlike conventional template lithography-based approaches, 3D-printing can be used to fabricate complex devices in a simple and cost-effective manner. In this paper, we report 3D-printed stretchable strain sensors that embeds a flexible conductive composite material in a hyper-plastic substrate. Three commercially available conductive filaments are explored, among which the conductive thermoplastic polyurethane (ETPU) shows the highest sensitivity (gauge factor of 5), with a working strain range of 0%–20%. The ETPU strain sensor exhibits an interesting behavior where the conductivity increases with the strain. In addition, an experiment for measuring the wind speed is conducted inside a wind tunnel, where the ETPU sensor shows sensitivity to the wind speed beyond 5.6 m/s.
Coupled Band Gaps in the Piezoelectric Composite Plate With Interconnected Electric Impedance
Authors: Li Lin , Jiang Zhou , Fan Yu , Li Jun
Published: November 2018

In this paper, we investigate the coupled band gaps created by the locking phenomenon between the electrical and flexural waves in piezoelectric composite plates. To do that, the distributed piezoelectric materials should be interconnected via a ‘global’ electric network rather than the respective ‘local’ impedance. Once the uncoupled electrical wave has the same wavelength and opposite group velocity as the uncoupled flexural wave, the desired coupled band gap emerges. The Wave Finite Element Method (WFEM) is used to investigate the evolution of the coupled band gap with respect to propagation direction and electric parameters. Further, the bandwidth and directionality of the coupled band gap are compared with the LR and Bragg gaps. An indicator termed ratio of single wave (RSW) is proposed to determine the effective band gap for a given deformation (electric, flexural, etc.). We show that the coupled band gap, despite directional, can be much wider than the LR gap with the same overall inductance. This might lead to an alternative to create sub-wavelength band gaps.
Application of Entropy in Crack Identification at Welding Joint With a New Smart Coating Sensor
Authors: Wang Xin , Wu Nan
Published: November 2018

An identification module is designed and studied to detect and evaluate the cracks at the welding joint area using a new smart coating sensor and entropy measurement. A new piezoelectric composite coating is applied at a welding joint to possibly charge the wireless data transmission module as an energy harvester. It also sends warning and dynamic signals for crack evaluation when the crack damage occurs. More specifically, entropy calculation is introduced to quantify the weak perturbations, which is caused by the material nonlinearity and crack breathing at the crack tip and hidden in the signal. In this paper, a finite element model (FEM) of a welded beam experiencing dynamic base motion is established as an example. The effects of material nonlinearity and crack breathing on structural dynamics response are simulated by creating nonlinear material property around the crack area and contact pair of crack walls, respectively. After obtaining the time domain vibration signal, crack severity is quantified using Sample Entropy. It is concluded that, even at very early stages of 5% of the beam thickness for the crack depth, the entropy variation is significant for a damaged beam compared with the healthy one.
Flexible 3-D Printed Circuits and Sensors
Authors: Mamer Trevor , Gonzales David , Newell Brittany , Garcia Jose , Leon-Salas Daniel , Vindrola Angello , Zigon Taylor
Published: November 2018

Electroactive polymers are a class of materials capable of reallocating their shape in response to an electric field while also having the ability to harvest electrical energy when the materials are mechanically deformed. Electroactive polymers can therefore be used as sensors, actuators, and energy harvesters. The parameters for manufacturing flexible electroactive polymers are complex and rate limiting due to number of steps, their necessity, and time intensity of each step. Successful 3D printing manufacturing processes for electroactive polymers will allow for scalability and flexibility beyond current limitations, improving the field, opening additional manufacturing possibilities, and increasing output. The goal for this research is to use additive manufacturing techniques to print conductive and dielectric substrates for building flexible circuits and sensors. Printing flexible conductive layers and substrates together allows for added creativity in design and application. In this work we have successfully demonstrated additive production of a simple flexible circuit using exclusively additive manufacturing.