bluuebunny/crossref_metadata_2025 huggingface dataset:
Design Research in Innovation Management: a pragmatic and human‐centered approach
Authors: Auernhammer Jan
Published: April 2020

This article outlines a pragmatic and human‐centered Design Research approach in Innovation Management. This research approach is of particular relevance when investigating Innovation Management under conditions of high uncertainty associated with changing environments and the complexity of transforming organizational architectures and business models. Under conditions of high uncertainty and complexity, research approaches that reduce complexity to specific factors are unsuitable. In contrast, Design Research in Innovation Management permits investigating Innovation Management under these conditions as it enables examining Innovation Management interventions and their impact within real‐world messiness. Design Research in Innovation Management empirically examines if the designed intervention provides a satisfactory and meaningful Innovation Management solution. This article provides a guide on how to examine Innovation Management interventions and how to generate practical knowledge. This practical knowledge enables practitioners to take action to facilitate innovation, and the approach allows viewing Innovation Management as a design practice. The outlined approach provides a new way to investigate and expand the discourse in the Innovation Management literature by developing practical knowledge in addition to theories and conceptual models.
The Parent Play Questionnaire: Development of a parent questionnaire to assess parent–child play and digital media use
Authors: Ahmadzadeh Yasmin I. , Lester Kathryn J. , Oliver Bonamy R. , McAdams Tom A.
Published: April 2020

We introduce the Parent Play Questionnaire (PPQ), a parent‐report measure designed to assess frequency of parent–infant play, parents’ attitudes towards play with their infant, and infants’ use of digital media. We describe measure development and empirical data across three samples of parent–infant dyads (total N = 414, offspring aged 0.3–2.5 years). Three latent factors explain the PPQ, corresponding with theoretically defined subscales. Summary scores showed good internal consistency and normally distributed results. Weak to moderate correlations were found between the frequency and attitude play scales, and with standardized measures of family social and emotional characteristics. Overall, frequency of digital media use was not correlated with play or broader family variables. Results suggest that the PPQ will be a useful tool for researchers interested in assessing parent–child play during early childhood.
Biological behaviour and clinical outcome in 42 cats with sarcoids (cutaneous fibropapillomas)
Authors: Wood Christopher J. , Selmic Laura E. , Schlag Ariel N. , Bacmeister Cynthia , Séguin Bernard , Culp William T. N. , Ayres Sara A. , Sumner Julia P. , Byer Brittney , Mayer Ursula K. , Liptak Julius M.
Published: April 2020

Feline sarcoids (or cutaneous fibropapillomas) are rare dermal neoplasms. There are currently no reported statistics concerning their clinical behaviour. Our objective with this retrospective, multi‐institutional study was to describe the clinical presentation and biological behaviour of sarcoids in cats and to determine the oncologic outcome following surgical resection. Medical records from a laboratory database and six contributing institutions were searched to identify cats with histologically confirmed sarcoids. Forty‐two cats were included in the study. The majority of sarcoids occurred on the face, particularly rostral locations such as the lips and nasal planum. Complete and incomplete histologic excision was achieved in 18 and 21 cats, respectively. The overall local recurrence rate was 40.5%. Complete histologic excision was associated with a significantly lower local recurrence rate (11.1%) and longer disease‐free interval (not reached) compared with cats with incompletely excised sarcoids (66.7% and 250 days, respectively). The 1‐ and 2‐year local recurrence rates were 0% and 7%, respectively, for cats with complete histologic excision, and 67% at both time intervals for cats with incomplete histologic excision. Five of the cats (83.3%) treated with curative‐intent surgical revision following local tumour recurrence had no further local recurrence. All cats that died secondary to tumour‐related causes had initial incomplete histologic excision and were euthanized because of local recurrence. Wide surgical resection of feline sarcoids is recommended to achieve complete histologic excision, local tumour control and a potential cure. For cats with incomplete histologic excision or local tumour recurrence, repeat surgical resection is recommended.
Application of FTIR fingerprints coupled with chemometric for comparison of stingless bee propolis from different extraction methods
Authors: Md Zin Nur Basyirah , Azemin Azierah , Mohd Rodi Muhammad Muslim , Mat Rashid Zalilawati , Mohd Khamsah Suryati
Published: April 2020

Propolis is a mixture of resin collected by the bees to build their hive. These mixtures contain natural remedy and used to treat variety of health-related problems. Unlike honeybee propolis, the study of stingless bee propolis still lacking. The important part of propolis study is the optimization of extraction procedures. The aim for this study is to employ chemometrics on FTIR data in order to discriminate the chemical fingerprinting of Malaysian stingless bee, Heterotrigona itama propolis yielded from different extraction methods, which were maceration, sonication and soxhlet. The chemical fingerprinting was obtained through Fourier Transform Infrared (FTIR). Principle component analysis (PCA) and hierarchical cluster analysis (HCA) were applied as pattern recognition methods for FTIR spectra. PCA of FTIR data for different extraction methods of stingless bee’s propolis revealed that variability of PC1 and PC2 is 84.76%. PCA’s variation in propolis by different extraction methods was classified based on specific functional groups arisen from the peaks. The FTIR fingerprinting of HCA of stingless bee’s propolis were distributed into three clusters based on percentages of ethanol, intensity of peaks and different fingerprint region. FTIR coupled with chemometric analysis showed classification of different extraction methods of propolis from PCA and HCA based on vibration of functional groups presence in the samples. Taken together, these results showed that different extraction methods play important role in detaining of chemical in propolis of stingless bee.
Investigation of active species in methanation reaction over cerium based loading
Authors: Mat Rosid Salmiah Jamal , Wan Abu Bakar Wan Azelee , Toemen Susilawati , Mohamad Yusoff Nurulhuda , Azid Azman , Wan Mokhtar Wan Nur Aini
Published: April 2020

A series of cerium oxide based catalyst has been studied by various cerium loadings that calcined at 1000oC using wet impregnation method. The potential Ru/Mn/Ce (5:35:60) /Al2O3 catalyst calcined at 1000oC was characterized using XRD, XPS, and BET analyses. As could be observed from the XRD analysis, at Ce ratio of 55% and 65%, both revealed the presence of RuO2 with tetragonal phase and intense, sharper peaks indicating to high crystallinity and in line with lower surface area, 50.95 m2/g in BET analysis. Meanwhile, CeO2 (cubic phase) and MnO2 (tetragonal phase) were also observed for 55%, 60%, and 65%, respectively. However, the presence of Al2O3 with rhombohedral phase at 55% and 65% was revealed as an inhibitor which decreased the CO2 conversion. The presence of active species on Ru/Mn/Ce (5:35:60) /Al2O3 catalyst has been confirmed using XPS analysis with the deconvolation peaks belonged to Ce4+ with the formation of CeO2 compound and Mn4+ for MnO2. The product formed in catalytic methanation was proposed to be H2O and CH3OH from GC and HPLC analysis.
Physicochemical properties and stability of Moringa oleifera seed oil-in-water emulsions as affected by different types of polysaccharide and emulsifier
Authors: Ibrahim Nor Hayati , Jin Ong Ji , Muhamad Nizaha Juhaida , Wan Ishak Wan Rosli
Published: April 2020

Moringa oleifera seed oil is a promising medicinal oil and converting it into a functional food emulsion is of current interest to widen its consumption. This study was aimed to investigate physicochemical properties and stability of M. oleifera seed oil-in-water emulsions as affected by interaction between polysaccharide i.e. xanthan gum (XG), guar gum (GG), carboxymethyl cellulose (CMC) and emulsifier i.e. sodium caseinate (NaCas) and whey protein isolate (WPI). Significant (p < 0.05) lower pH values in XG-WPI (4.98) and XG-NaCas (4.72) emulsions were observed as opposed to other emulsions (5.19-5.40). The interaction between XG-WPI and XG-NaCas has resulted in significant (p < 0.05) higher apparent viscosity values (at 0.42s-1) of their respective emulsions with 35.10 and 10.75 Pa.s respectively, as compared to other emulsions (0.35–0.85 Pa.s). These desirable characteristics of pH and viscosity profile had favoured an excellent creaming stability (no phase separation) of the emulsions. Regardless of emulsifier used, XG emulsions exhibited a significant (p < 0.05) higher scavenging activity (34.84 – 41.52%) towards 1,1-diphenyl-2-picrylhydrazyl free radicals than other emulsions. Total oxidation values (11.18 – 24.93) under an accelerated oxidation period (48 hours, 60°C) were more influenced by peroxide value rather than anisidine value. All WPI emulsions and CMC-NaCas emulsion showed significant (p < 0.05) low total oxidation values relative to other emulsions. All emulsions however showed no significant difference in their turbidity loss rate (1.2 – 3.3 x 10-3). These findings have made possible of producing a good quality of a functional food emulsion based on M. oliefera seed oil, particularly when the system was stabilized by XG-WPI. This was mainly due to their positive interaction that has affected on pH and viscosity of emulsion, which eventually led to a good stability towards creaming and inhibition of lipid oxidation.
The association of heavy metals concentration in air and health risk assessment in Paka, Malaysia
Authors: Muhammad Amin Siti Noor Syuhada , Azid Azman , Khalit Saiful Iskandar , Samsudin Mohd Saiful , Ku Yusof Ku Mohd Kalkausar
Published: April 2020

Heavy metals are classified as the materials that have density five times higher than water. They can be spread in the world through air, water and other routes. In this study, it was focused on heavy metals in air. Paka has be choosen in this study as it is the industrial estate that contributed to air pollution. The aim of this study was to determine an association between heavy metals concentration in air and health risk assessment in Paka, Malaysia. Eight points were selected for this study within two monsoon seasons. The sampling for southwest monsoon was done in August and September 2017 while for northeast monsoon was done in December 2017 and February 2018. The samples were digested by using aqua regia method. The concentration of heavy metals was analysed by using inductively coupled plasma mass spectrometry (ICPMS). For southwest monsoon, the results showed that the concentration of Fe was the highest with the value of mean ±SD (0.272 mg/Kg ± 0.103) and the lowest mean concentration was recorded for Cu with the value of 0.002 mg/Kg ± 0.001. For northeast monsoon, Fe was recorded the highest concentration of heavy metals and As was the lowest with the value 0.125 mg/Kg ± 0.041 and 0.002 mg/Kg ± 0.001, respectively. The health risk assessment indicated no risks from these metals as the HQs and HIs of six metals were almost all lower than the safe level (=1) for the industrial workers. The HI values were decreased in the order of Fe>Cd>Pb>As>Zn>Cu. Fe and Cd showed higher values close to safe level, while Zn and Cu were lowest. It could be concluded that the industrial emission was the major source of heavy metals in the atmosphere along Paka industrial area. The human health risk assessment has proved to be a powerful tool to distinguish heavy metals and exposure routes of most concerns in urban environments to estimate the risk of mix metal contaminates.
Aliphatic hydrocarbon biomarkers of Sekar Kurung Gresik crude oil
Authors: Nirmala Dyah , Burhan R.Y.Perry , Suprapto Suprapto , Zetra Yulfi
Published: April 2020

Characterization of petroleum biomarker from Sekar Kurung Gresik, was carried out to investigate its organic composition, depositional environment and oil maturity. The oil sample was extracted and fractionated using column chromatography to derive aliphatic hydrocarbon fraction.  The aliphatic hydrocarbon compounds were analyzed using gas chromatography-mass spectrometer (GC-MS). The GC-MS analysis shows that n-alkanes compound (C14-C28), isoprenoid alkanes (iC15 iC16 and iC18-iC20), a bicyclic sesquiterpene, eudesmane, cadinane, hopane, bicadinane, gammacerane and diasterane were observed. The identified compounds show that the crude oil compounds were derived from terrestrial higher plants, the contribution of bacterial activity and the oxic deposition environment (Pr/Ph = 5.3 (<1)). The oil analyzed is a mature oil.
Synthesis and molecular docking of isonicotinohydrazide derivatives as anti-tuberculosis candidates
Authors: Ruswanto Ruswanto , Mardianingrum Richa , Lestari Tresna , Nofianti Tita , Rahayuningsih Nur
Published: April 2020

Tuberculosis (TB) is a chronic disease as a result of Mycobacterium tuberculosis. It can affect all age groups, and hence, is a global health problem that causes the death of millions of people every year. One of the drugs used in tuberculosis treatment is isonicotinohydrazide (Isoniazid). In this study, N'-benzoylisonicotinohydrazide derivative compounds (a-l) were prepared using acylation reactions between isonicotinohydrazide and benzoyl chloride derivatives, employing the reflux method. Molecular docking studies suggested that all of the compounds had better interaction with Mycobactarium tuberculosis enoyl-acyl carrier protein reductase (InhA) than isonicotinohydrazide. It can be concluded that N'-benzoylisonicotinohydrazide derivatives (a-l) can be used as anti-tuberculosis candidates. The docking results obtained revealed that all of the compounds were interacted well with InhA, with compound g exhibiting the best interaction.
Preliminary studies on hydrothermal synthesis of zeolite from Malaysian kaolinite clays
Authors: Abdullahi Tijjani , Harun Zawati , Othman Mohd Hafiz Dzarfan , Yusof Khairul Nazri , Rahmawati Ainun , Yunos Muhamad Zaini , Lajis Mohd Amri , Yusof Yusri
Published: April 2020

The use of kaolin as a source of silica and alumina for synthesis of zeolite has been widely reported with various compositions and processing routes. However, since kaolin is highly influenced by geological origin and geographical formation, coupled with the processing method, two different crude kaolin were obtained at various locations in Peninsular Malaysia to serve as precursor for synthesis of zeolite. Hydrothermal treatments were made at reasonable low temperature of 90°C in an oven. The synthesized product was then analyzed using X-ray diffraction and scanning electron microscopy, to evaluate the potentials of the process and the product. The outcome of the analysis suggested that the breaking down of the clay structure and the armophization process can improve raw material reactivity. However, the crystallinity and composition of the crude kaolin together with appropriate incubation time can greatly influence the synthesis process and the product.
Biosynthesized gold nanoparticles supported on magnetic chitosan matrix as catalyst for reduction of 4-nitrophenol
Authors: Saffee Norfazreen , Shamsuddin Mustaffa , Abd Karim Khairil Juhanni
Published: April 2020

The design and environmentally-safe synthesis of magnetically recoverable solid-supported metal nanoparticles with remarkable stability and catalytic performance has significant industrial importance. In the present study, we have developed an inexpensive bioinspired approach for assembling gold nanoparticles (AuNPs) in magnetic chitosan network under green, mild and scalable condition. AuNPs were well loaded on the surface of the magnetic support due to the presence of hydroxyl (-OH) and amino (-NH2) groups in chitosan molecules that provided the driving force for the complexation reaction with the Au(III) ions. Reduction of the Au(III) to Au(0) is achieved by using Melicope ptelefolia aqueous leaf extract. The synthesized magnetic chitosan supported biosynthesized Au nanocatalyst was characterized using Fourier Transform Infrared (FT-IR), Carbon, Hydrogen and Nitrogen (CHN), Transmission Electron Microscopy (TEM), X-Ray Diffraction (XRD) and Atomic Absorption Spectroscopy (AAS) analyses. FTIR spectrum of magnetic chitosan shows peaks at 1570 cm-1 indicative of N-H bending vibration and at 577 cm-1 which designates the Fe-O bond. CHN analytical data further supported the coating of chitosan onto the magnetite. TEM analysis shows an amorphous layer around the magnetite core which supported the coating of chitosan on the magnetite surface and the average particle size of AuNPs calculated was 7.34 ± 2.19 nm. XRD analysis shows six characteristics peaks for magnetite corresponding to lattice planes (220), (311), (400), (422), (511) and (440) in both the magnetite and magnetic chitosan samples (JCPDS file, PDF No. 65-3107). Meanwhile, XRD analysis of catalyst shows characteristic peaks of AuNPs at 2q (38.21°, 44.38°, 62.2°, 77.32° and 80.76°) are corresponding to (111), (200), (220), (311) and (222) lattice plane (JCPDS file, PDF No.04-0784). AAS analysis shows the loading of AuNPs as 5.4%. The rate constant achieved for the reduction of 4-nitrophenol to 4-aminophenol in the presence of hydrazine hydrate using 10 mg of catalyst is 0.0046 s-1. The magnetic chitosan supported AuNPs is effective as catalyst for the reduction of 4-nitrophenol.
Impact of communication delay on distributed load frequency control (dis-LFC) in multi-area power system (MAPS)
Authors: Imam Auwal Mustapha , Chaudhary Kashif , Kunya Abdullahi Bala , Rizvi Zuhaib , Ali Jalil
Published: April 2020

AIn this paper, impact of communication delay on distributed load frequency control (dis-LFC) of multi-area interconnected power system (MAIPS) is investigated. Load frequency control (LFC), as one of ancillary services, is aimed at maintaining system frequency and inter-area tie-line power close to the scheduled values, by load reference set-point manipulation and consideration of the system constraints. Centralized LFC (cen-LFC) requires inherent communication bandwidth limitations, stability and computational complexity, as such, it is not a good technique for the control of large-scale and geographically wide power systems. To decrease the system dimensionality and increase performance efficiency, distributed and decentralized control techniques are adopted. In distributed LFC (dis-LFC) of MAIPS, each control area (CA) is equipped with a local controller and are made to exchange their control actions by communication with controllers in the neighboring areas. The delay in this communication can affect the performance of the LFC scheme and in a worst case deteriorates power system stability. To investigate the impact of this delay, model predictive controller (MPC) is employed in the presence of constraints and external disturbances to serve as LFC tracking control. The scheme discretizes the system and solves an on-line optimization at each time sample. The system is subjected to communication delay between the CAs, and the response to the step load perturbation with and without the delay. Time-based simulations were used on a three-area MAIPS in MATLAB/SIMULINK environment to verify the investigations. The overshoot and settling time in the results reveals deterioration of the control performance with delay.  Also, the dis-LFC led to zero steady states errors for frequency deviations and enhanced the MAIPS’ performance. With this achievement, MPC proved its constraints handling capability, online rolling optimization and ability to predict future behavior of systems.
Effectiveness of visible and ultraviolet light emitting diodes for inactivation of Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli: A comparative study
Authors: Malik Sameen Ahmed , Swee Tan Tian , Nik Malek Nik Ahmad Nizam , Yahya Azli , Emoto Takahiro , Akutagawa Masatake , Meng Leong Kah , Hou Tan Jia , Tengku Alang Tengku Ahmad Iskandar , Chia Hiik Kelvin Ling
Published: April 2020

The rapid use of ultraviolet light emitting diodes (UV-LEDs) in various disinfection applications is growing tremendously due to their advantages unachievable using UV lamps. In this study, a comparison of standard LED at 460 nm wavelength and UVA LED at 385 nm was conducted to determine their effectiveness in disinfection of frequently isolated pathogens in hospitals (Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli). Determination of disinfection efficiency was carried out by measuring inhibition zone. Effects of varied exposure time on the inactivation of pathogenic microorganisms was studied. The results demonstrated that LED does not have germicidal activities. The highest inactivation for UVA LED was achieved for Pseudomonas aeruginosa. Linear relationship was found between exposure time and log reduction. This study showed that UVA LEDs can effectively inactivate significantly higher number of microorganisms hence can be used in disinfection of various applications.
Sulfonated PEI membrane with GPTMS-TiO2 as a filler for potential direct methanol fuel cell (DMFC) applications
Authors: Muliawati Eka Cahya , Ismail Ahmad Fauzi , Jaafar Juhana , Widiastuti Nurul , Santoso Mardi , Salleh Muhammad Taufiq , Nurherdiana Silvana Dwi , Atmaja Lukman
Published: April 2020

This study addresses the effect of GPTMS-modified titanium dioxide (TiO2) which composited sulfonated polyetherimide (SPEI) as a proton exchanger on direct methanol fuel cell (DMFC). The membrane fabrication is chiefly based on phase-inversion method after GPTMS-TiO2 and SPEI were prepared separately. Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electronic microscopy (SEM), ion exchange capacity (IEC), proton conductivity, water uptake, methanol permeability and mechanical properties were utilized to characterize and measure their physical and thermal stability. As a result, a high water uptake and IEC performance are achieved using the fabricated membrane as well as low methanol permeability which compared to Naﬁon 117 membranes. The membrane performance is improved using 20 wt% SPEI and 5wt% TiO2-5 wt% GPTMS with an optimum result of 3 times lower in terms of methanol uptake and methanol permeability with proton conductivity of 21 mS.cm-1 than the remaining membranes and Nafion. Thus, the obtained results of SPEI/TiO2-GPTMS can be promoted as a novel polymeric membrane for DMFC.
Synthesis and characterization of graphene derived from rice husks
Authors: Ismail Mohammad Shafri , Yusof Norhaniza , Mohd Yusop Mohd Zamri , Ismail Ahmad Fauzi , Jaafar Juhana , Aziz Farhana , Abdul Karim Zulhairun
Published: April 2020

Graphene was successfully synthesized by activating rice husk ash (RHA) using potassium hydroxide (KOH) at 800 oC with 1:2 impregnation ratio. Raman spectroscopy analysis confirmed the presence of graphitic structure. The demonstrated methodology utilizes RHA as carbon source and used as sacrifice to prevent oxidation during synthesis process on the mixture of KOH and RHA against air at high temperature. The novelty of this synthesis methodology use environmentally-friendly biomass resource as a starting material, does not utilize catalysts, and prove that graphene can be synthesized at a relatively low synthesis temperature.
Evaluation on transmutation of minor actinides discharged from PWR spent fuel in the RSG-GAS research reactor
Authors: Setiawan Muhammad Budi , Kuntjoro Sri , Husnayani Ihda , Udiyani Pande Made , Surbakti Tukiran
Published: April 2020

The evaluation of RSG-GAS research reactor for transmutation reactor was proposed to study its effectiveness to transmute minor actinides (MA), specifically Am-241, to support geologic storage/disposal. The Am-241 radionuclide was assumed to be discharged from 1000MWe PWR’s spent fuel. The mass of Am-241 discharged from within a year operation of 1000MWe PWR was 1.65E+03 gram, while the optimum Am-241 mass which can be transmuted in RSG-GAS - and still meet the safety requirements of reactivity - was 8.0E+03 gram. This was equivalent to about cumulative Am-241 discharged from 5 units of 1000MWe PWR. In 10 cycles of RSG-GAS operation (about 2 years), the remaining of Am-241 is only about 100 grams. The ratio of Am-241 transmuted (8.0E+03 gram) and Am-241 produced in the RSG-GAS core (1.98E-02 gram) within 1-year operation shows the effectiveness of RSG-GAS as a transmutation reactor.
Radiological dose assessment due to hypothetical nuclear power plant operation in Mersing, Johor, Malaysia
Authors: Omar Nurlyana , Koh Meng-Hock , Hashim Suhairul
Published: April 2020

Malaysia has considered for some time to adopt nuclear power to cater to the increasing demand of electricity following other developed Asian countries such as Japan, Korea, and China. In implementing a nuclear power plant, strict regulations and guidelines by the International Atomic Energy Agency (IAEA) and International Commission on Radiological Protection (ICRP) must be fulfilled before any construction license is given for a new nuclear power program. One of the assessments include the estimation of potential radiological risks to both humans and environment from routine and accidental release of radioactive effluent from the nuclear power plant (NPP). In this work, simulations of radionuclide dispersion from a hypothetical NPP site in Mersing, Johor will be presented. The simulation was performed based on the Lagrangian atmospheric dispersion model using the HYSPLIT software. The radioactive effluent release rate was approximated to the value found in the Fukushima Dai-ichi accident in 2011. Meteorological data of 2017 were utilized in this study. Simulation results showed that the dispersion of radioactive effluent from the hypothetical NPP can potentially affect areas around Johor Bahru district, Singapore, and even some areas in Indonesia.
Study of microstructure modification on La0.7Sr0.3Co0.2Fe0.8O3-δ (LSCF 7328) asymmetric flat membrane
Authors: Nurherdiana Silvana Dwi , Khoiroh Naimatul , Ilham Ahyudia Malisa , Iqbal Rendy Muhamad , Utomo Wahyu Prasetyo , Othman Mohd Hafiz Dzarfan , Fansuri Hamzah
Published: April 2020

The LSCF 7328 (La0.7Sr0.3Co0.2Fe0.8O3-δ) asymmetric flat membranes were successfully prepared via a phase-inversion method followed by sintering at 1200 °C. In this study, a variety of poly(ethylene glycol) (PEGs) as the pore-forming agent, with  3 wt% composition and a wide ranges of molecular weight (Mw) (200 to 8000 Da) were used to tests its’ effect to the properties of LSCF  membranes. The results show that the PEGs, as additives, were able to modify the pore morphology and mechanical properties of the LSCF 7328 membrane. The morphological evidence from SEM images showed that the LSCF membranes have an asymmetric configuration, comprised of sponge-like and finger-like pores which are integrated with a dense layer. The variation in average pore size is clearly seen, starting from 13.00 to 135.33 μm, following the increase in PEGs molecular weight. The LSCF membranes which were prepared using PEG additive have higher hardness (1.2 – 13.6 Hv) than the membrane with no PEG  (0.2 Hv). In contrast, the porosity and pore volume of the membranes decrease with the increase of PEGs molecular weight. The decrease might be due to the formation of various closed macro-voids as the molecular weight of PEGs increases. Furthermore, the thermal expansion coefficient of the membrane with different PEGs molecular weight (ie. 400, 600, 4000 and 6000) Da posses no significant different, i.e. around 16 x 10-6 °C-1, although the membrane showed different morphology and mechanical properties.
Presynaptic development is controlled by the core active zone proteins CAST/ELKS
Authors: Radulovic Tamara , Dong Wei , Goral R. Oliver , Thomas Connon I. , Veeraraghavan Priyadharishini , Montesinos Monica Suarez , Guerrero‐Given Debbie , Goff Kevin , Lübbert Matthias , Kamasawa Naomi , Ohtsuka Toshihisa , Young Samuel M.
Published: April 2020

Key points

CAST/ELKS are positive regulators of presynaptic growth and are suppressors of active zone expansion at the developing mouse calyx of Held.

CAST/ELKS regulate all three CaV2 subtype channel levels in the presynaptic terminal and not just CaV2.1.

The half‐life of ELKS is on the timescale of days and not weeks.

Synaptic transmission was not impacted by the loss of CAST/ELKS.

CAST/ELKS are involved in pathways regulating morphological properties of presynaptic terminals during an early stage of circuit maturation.

Many presynaptic active zone (AZ) proteins have multiple regulatory roles that vary during distinct stages of neuronal circuit development. The CAST/ELKS protein family are evolutionarily conserved presynaptic AZ molecules that regulate presynaptic calcium channels, synaptic transmission and plasticity in the mammalian CNS. However, how these proteins regulate synapse development and presynaptic function in a developing neuronal circuit in its native environment is unclear. To unravel the roles of CAST/ELKS in glutamatergic synapse development and in presynaptic function, we used CAST knockout (KO) and ELKS conditional KO (CKO) mice to examine how their loss during the early stages of circuit maturation impacted the calyx of Held presynaptic terminal development and function. Morphological analysis from confocal z‐stacks revealed that combined deletion of CAST/ELKS resulted in a reduction in the surface area and volume of the calyx. Analysis of AZ ultrastructure showed that AZ size was increased in the absence of CAST/ELKS. Patch clamp recordings demonstrated a reduction of all presynaptic CaV2 channel subtype currents that correlated with a loss in presynaptic CaV2 channel numbers. However, these changes did not impair synaptic transmission and plasticity and synaptic vesicle release kinetics. We conclude that CAST/ELKS proteins are positive regulators of presynaptic growth and are suppressors of AZ expansion and CaV2 subtype currents and levels during calyx of Held development. We propose that CAST/ELKS are involved in pathways regulating presynaptic morphological properties and CaV2 channel subtypes and suggest there is developmental compensation to preserve synaptic transmission during early stages of neuronal circuit maturation.
An Improved Test Method of LiFePO4/Graphene Hybrid Cathode Lithium-Ion Battery and the State of Charge Estimation
Authors: Li Meiying , Guo Zhiping , Li Yuan , Wu Wenliang
Published: April 2020

The state of charge (SoC) of the battery is a typical characterization of the operating state of the battery and criterion for the battery management system (BMS) control strategy, which must be evaluated precisely. The establishment of an accurate algorithm of SoC estimation is of great significance for BMS, which can help the driver judge the endurance mileage of electric vehicle (EV) correctly. In this paper, a second-order resistor-capacity (RC) equivalent circuit model is selected to characterize the electrical characteristics based on the electrochemical model of the LiFePO4/graphene (LFP/G) hybrid cathode lithium-ion battery. Moreover, seven open circuit voltage (OCV) models are compared and the best one of them is used to simulate the dynamic characteristics of the battery. It is worth mentioning that an improved test method is proposed, which is combined with least square for parameters identification. In addition, the extended Kalman filter (EKF) algorithm is selected to estimate the SoC during the charging and discharging processes. The simulation results show that the EKF algorithm has the higher accuracy and rapidity than the KF algorithm.
A Computational Comparative Study of the Lithium Diffusion in Amorphous Silicon Spheres, Rods, and Circular Disks
Authors: Le Minh-Quy , Nguyen Huu-Tu , Bui Thanh-Lam
Published: April 2020

We study through extensive finite element analysis the lithium diffusion in small elements of Si anodes under the forms of spheres, rods, and circular disks for Li-ion batteries. Elastoplastic properties of the amorphous silicon are assumed to be lithium concentration-dependent. Effects of the normalized flux of Li-ions on the lithium concentrations, stresses, and total equivalent plastic strains are considered. Effects of the disk's thickness are also included. At a given normalized flux, the heterogeneity of the lithiation, stresses, and plastic deformation increases in the order: disk, sphere, and rod. The thinner disk the better performance is. Below a critical value of the normalized flux of Li-ions, silicon spheres and disks exhibit linear elasticity and homogeneous distribution of Li-ions, whereas silicon rods undergo always plastic deformation after lithiation. When the radii of these three structures are smaller than several micrometers and the normalized flux is taken as 95% of their critical value, the charge time falls in the range from minutes to several hours. Our findings will help to optimize the charge and geometrical parameters for silicon anodes.
Organic Rankine Cycle Optimization With Explicit Designs of Evaporator and Radial Inflow Turbine
Authors: Bekiloğlu Hasan Eren , Bedir Hasan , Anlaş Günay
Published: April 2020

Although there are studies on optimizing organic Rankine cycles (ORCs) through individual components, in this study, for the first time, both evaporator and turbine designs are included in a multiobjective optimization. Twenty-eight working fluids are used to find optimum cycle parameters for three source temperatures (90, 120, and 150 °C). A mean-line radial inflow turbine model is used. Nondominated Sorting Genetic Algorithm II is utilized to minimize total evaporator area per net power output and maximize performance factor simultaneously. The technique for Order Preference by Similarity to Ideal Situation (TOPSIS) procedure is followed to obtain ideal solutions. A group of working fluids with highest net power output is determined for each heat source temperature. Optimized geometric parameters of the evaporator vary in a narrow range independent of the working fluid and the source temperature, but evaporator PPTD and degree of superheating depend on the working fluid. The specific speed, the pressure ratio through the turbine, and the nozzle inlet-to-outlet radius ratio do not change significantly with cycle conditions.
Monitoring Polymer-Enhanced Foam Displacements Through Heterogeneous Porous Media: A Pore-Scale Study
Authors: Ardakani Alireza Ghaderi , Mohammadi Alamooti Amir Hossein , Rasaei Mohammad Reza , Javadi Aliyar , Ghazanfari Mohammad Hossein , Davarzani Hossein
Published: April 2020

In this work, fundamental understanding of phase displacements involved in polymer-enhanced air foam is investigated which was not well discussed in the available literature. To do this, a series of foam injection experiments were performed on heterogeneous rock-look-alike micromodels in the presence and absence of a single fracture. The models were initially saturated with crude oil and experienced post polymer-enhanced foam injection process. We observed for the first time the mechanism of synergetic upstream snap-off and lamella division in the vicinity of the area where the permeability contrast was obvious. Observations showed two opposite effects of oil emulsioning and bubble coalescence when gas bubbles came in contact with oil in pore bodies. Fractal dimension analysis of front polymer-enhanced foam illustrates a noticeable improvement in oil displacement. Primary enhanced foam injection to oil saturated micromodel causes bubble coarsening which leads to less efficient oil displacement process. The lower the polymer concentration, the less stable the foam; consequently, the less efficient oil displacement is observed. Lower viscosity oil results in lower recovery efficiency as the stability of foam decreases. To shed light on the dynamic behavior of polymer–surfactant interface, some dynamic surface tension tests were conducted. Results showed that repellency between surfactant and polymer molecules causes surfactant molecules to be present on the surface making the initial dynamic interfacial tension (IFT) decrease. Results of this work help to better understand how polymer could enhance the efficiency of foam floods in heterogeneous systems.
An Investigation of the Tribological Behavior of Hf-Based Bulk Metallic Glass and Crystalline Alloys
Authors: Abad M.D. , Browne D.J.
Published: April 2020

The use of bulk metallic glasses (BMGs) as advanced materials for many applications is attractive, due to their improved mechanical performance over their crystalline counterparts: typically providing higher strength and hardness. Hafnium-based alloys of two similar compositions were prepared by arc melting and suction casting to produce 6-mm-diameter cast rods of an amorphous alloy and a crystalline one. The selected compositions were Hf48Cu29Ni10Al13 (amorphous) and Hf58Cu20Ni16Ti6 (crystalline), as confirmed by X-ray diffraction. The hardness of the amorphous alloy was higher than that of the crystalline one. A detailed study of their tribological behavior was carried out, using a pin-on-disc wear tester, with tungsten carbide counterface balls. There were no statistically significant differences in friction coefficient or wear-rates between the two materials tested. Adherence of material from the tested alloy to the ball, and vice versa, were detected. No changes to the crystallinity of the bulk samples were induced by the wear process, as determined by X-ray diffraction. However, amorphous debris were obtained from both samples, indicating the possibility of local vitrification of particles detached from the crystalline alloy and confirming thermal stability of the amorphous alloy.
A Multi-domain Approach to the Stabilization of Electrodynamic Levitation Systems
Authors: Galluzzi Renato , Circosta Salvatore , Amati Nicola , Tonoli Andrea , Bonfitto Angelo , Lembke Torbjörn A. , Kertész Milan
Published: April 2020

The Hyperloop transportation system paradigm has gained increasing attention in the last years due to its potential advantages in technology, territory, and infrastructure. From an engineering point of view, it would lead to fast, safe, efficient transportation of passengers and cargo. The stability of the electrodynamic levitation system represents a key enabling aspect of Hyperloop. In this context, the state of the art presents numerous attempts to stabilize these systems without definitive guidelines on how to attain proper, stable behavior. Furthermore, research has provided extensive literature in the context of electrodynamic bearings, which requires proper interpretation and generalization into the translational domain. In this paper, we address the stabilization of levitation systems by reproducing the strong interaction between the electrodynamic phenomenon and the mechanical domain. A novel lumped-parameter model with a multiple-branch circuit is proposed and tuned through finite-element simulations to replicate the electrodynamic behavior. The multi-domain equations are linearized and the unstable nature of the levitation system is identified and discussed. Then, a suitable method to add damping and optimize stability is studied. Finally, the linearized model is compared with the nonlinear representation to validate the followed approach.
Heat Transfer Coefficient Augmentation for a Shaped Film Cooling Hole at a Range of Compound Angles
Authors: Haydt Shane , Lynch Stephen
Published: April 2020

Film cooling holes with shaped diffusers are used to efficiently deliver coolant to the surface of a gas turbine part to keep metal temperatures low. Reducing the heat flux into a component, relative to a case with no coolant injection, is the ultimate goal of film cooling. This reduction in heat flux is primarily achieved via a lower driving temperature at the wall for convection, represented by the adiabatic effectiveness. Another important consideration, however, is how the disturbance to the flowfield and thermal field caused by the injection of coolant augments the heat transfer coefficient. The present study examines the spatially resolved heat transfer coefficient augmentation, measured using a constant heat flux foil and infrared (IR) thermography, for a shaped film cooling hole at a range of compound angles. Results show that the heat transfer coefficient increases with the compound angle and the blowing ratio. Due to the unique asymmetric flowfield of a compound angle hole, a significant amount of augmentation occurs to the side of the film cooling jet, where the very little coolant is present. This causes local regions of increased heat flux, which is counter to the goal of film cooling. Heat transfer results are compared with adiabatic effectiveness and flowfield measurements from a previous study.
Simulation of a Set of Lithium-Ion Batteries With Composite Phase Change Materials and Heating Films Thermal Management System at Low Temperature
Authors: Tian Dongbo , Liu Weijun , Zhang Shuhua , Liu Yuan
Published: April 2020

Two different kinds of composite phase change materials (PCMs)—a high thermal conductive 80 wt% paraffin wax (PW)/expanded graphite (EG) composite and a 75 wt% PW/silica aerogel (SA) with a low thermal conductivity—are prepared and they characterized the thermophysical parameters. Then, a numerical model of battery pack based on composite phase change materials coupled with polyimide (PI) electric heating films is established at −20 °C. The temperature of monitoring points set in model and maximum and minimum temperature of the batteries in the pack are measured during discharge at 1C and 2C. By comparing the battery pack filled with PW/EG composite and the pack consisting of PW/SA composite, we intend to choose an appropriate one of the two composite PCMs to improve the lithium-ion batteries performance at low temperature. The results indicate that in spite of a good heating performance in heating process, the PW/SA composite induces an even higher temperature difference over the battery pack. Although PW/EG composite causes a large temperature difference at the end of heating film heating, it can quickly restore the uniformity of the battery pack. The PW/EG composite plays a more important role in improving the performance of the lithium-ion batteries at low temperature.
Mitigating Scattering Effects in Light-Based Three-Dimensional Printing Using Machine Learning
Authors: You Shangting , Guan Jiaao , Alido Jeffrey , Hwang Henry H. , Yu Ronald , Kwe Leilani , Su Hao , Chen Shaochen
Published: April 2020

When using light-based three-dimensional (3D) printing methods to fabricate functional micro-devices, unwanted light scattering during the printing process is a significant challenge to achieve high-resolution fabrication. We report the use of a deep neural network (NN)-based machine learning (ML) technique to mitigate the scattering effect, where our NN was employed to study the highly sophisticated relationship between the input digital masks and their corresponding output 3D printed structures. Furthermore, the NN was used to model an inverse 3D printing process, where it took desired printed structures as inputs and subsequently generated grayscale digital masks that optimized the light exposure dose according to the desired structures’ local features. Verification results showed that using NN-generated digital masks yielded significant improvements in printing fidelity when compared with using masks identical to the desired structures.
Efficient Dynamic Parameter Identification Framework for Machine Tools
Authors: Semm Thomas , Sellemond Markus , Rebelein Christian , Zaeh Michael F.
Published: April 2020

Modeling the dynamic behavior of a machine tool accurately is a difficult but crucial task when optimizing a machine tool’s design. An accurate representation of the real behavior is essential to ensure the transferability of simulations from a virtual prototype to a physical prototype. Due to the complexity of modern machine tools, a large number of parameters have an influence on the dynamic behavior. The parameterization of the used dynamic models is still challenging, especially if intricate local models are used for the individual effects. This paper presents an efficient framework for parameterizing a dynamic model of a machine tool containing linear local damping and stiffness parameters. For parameter identification, measurements of single components on simple test rigs as well as measurements of the whole machine tool were carried out. Different numerical optimization algorithms as well as objective functions were compared and applied to a three-axis machine tool structure for parameter fitting. By using a parametric reduced-order flexible multibody model for the fitting, high accuracy can be combined with high computational efficiency. The use of the presented approach allows an efficient parameter estimation and lays the groundwork for an influence analysis and the targeted optimization of a machine tool.
A Professional Development Activity to Better Support International Graduate Teaching Assistants in Evaluating Scientific Writing
Authors: Walsh Lisa L. , Jia Zhigang , Vernon Julianne
Published: April 2020

Graduate teaching assistants (GTAs) who are English language learners at American institutions often endure xenophobia, pressures to conform to American culture, and visa restrictions on working. Quantitative data we collected from the Introduction to Biology Laboratory course taught at a large R1 university indicate paper grading discrepancies between international and domestic GTAs. Qualitative data highlight international GTAs’ concerns regarding grading load and language barriers. To alleviate the burden on international GTAs, we provide a professional development activity for professors to use in course planning meetings based on feedback from GTAs. Group reflection, discussion, and modification of a rubric are recommended in order to train GTAs in assessing scientific writing to collaboratively build expectations as a teaching team.
STEM BUILD: An Online Community To Decrease Barriers to Implementation of Inclusive Tactile Teaching Tools
Authors: Ramirez Melissa V. , Gordy Claire L.
Published: April 2020

Access to 3D printing and other “maker” technologies has opened new doors for the creation of classroom activities using physical models. Multiple strategies for implementing 3D-printed models exist, and work to define best practices is ongoing. We outline the strengths and weaknesses of common strategies for employing physical models in undergraduate biology courses and describe a novel strategy that we have developed to pair 3D-printed models with guided inquiry learning to create inclusive and interactive learning experiences. We further introduce the STEM BUILD website, a resource that we have developed to facilitate collaboration among instructors, makers, researchers, and Universal Design for Learning experts and reduce barriers to broad implementation of inclusive kinesthetic learning activities.