bluuebunny/crossref_metadata_2025 huggingface dataset:
Conformational transitions of bio-molecular systems studied using adaptive bond bending elastic network model
Authors: Srivastava Amit
Published: August 2019

Conformational transitions in proteins are essential for biological functions. Such transitions involve short-lived conformational states that are difficult to detect experimentally. Motivated by the utility and efficiency of elastic network models for describing the collective dynamics of proteins, in this study we present a new adaptive bond bending elastic network model for studying the conformational transition pathway of adenylate kinase and leucine transporter. Assuming that all the native contacts within these proteins are identical, we assigned a bond binding energy to the native contacts and computed the free energy of each image along the transition pathway. After plotting the free energy profiles, we found a few metastable intermediate states, separated by the free energy barriers. The observed intermediate states and the transition pathways for all proteins were in good agreement with those of the other methods and molecular dynamics simulations.
Strong optomechanical coupling of light and highly confined acoustic phonons in slot dual-beam phoxonic crystal cavities
Authors: Lin Tzy-Rong , Chang Chieh-Chun , Hsu Jin-Chen
Published: August 2019

In this study, strong optomechanical (OM) coupling is proposed through the introduction of a slot in a dual-beam phoxonic crystal cavity structure. The structure can support a confined optical slot mode and localized phononic cavity modes to interact effectively through the slot surfaces. In addition to using conventional OM coupling rates for evaluating the coupling strength of photonic and phononic modes, we consider the optical forces induced by the optical slot mode to discuss the coupling between different mode pairs and the underlying mechanisms of the strong OM coupling. The optical field can induce radiation pressure and electrostrictive forces in the structure. We demonstrate that the radiation pressure dominates the coupling enhancement of photonic and phononic modes because of the slot, whereas the electrostrictive surface pressure plays a minor role and the electrostrictive body force has a negligible contribution. On the basis of the optical forces, we can then calculate the acoustic phonon spectrum through optical excitation. The spectrum indicates the appearance of strong OM coupling in the additional phononic cavity modes. The results suggest that the slot dual-beam cavity structure can be a promising choice for tailoring effective optical forces in micro- and nano-optomechanical systems for enhancing OM coupling.
From the molecular quadrupole moment of oxygen to the macroscopic quadrupolarizability of its liquid phase
Authors: Slavchov Radomir I. , Dimitrova Iglika M. , Menon Angiras
Published: August 2019

Liquid oxygen is an example for a quadrupolar medium—a dense fluid made of nonpolar molecules carrying a significant quadrupolar moment. In this work, we present a method for the computation of the macroscopic quadrupolarizability of such a quadrupolar liquid. As a first step, the quadrupole moment and the molecular quadrupolarizability of O2 are calculated from first principles. Next, we apply a model generalizing Onsager’s dielectric cavity theory to compute the macroscopic quadrupolarizability of liquid oxygen under a wide range of conditions. Literature data for the density and dielectric permittivity of oxygen are used to determine the cavity size independently.
Vibrational solvatochromism of the ester carbonyl vibration of PCBM in organic solutions
Authors: Yu Yue , Shi Liang
Published: August 2019

Ester carbonyl stretch in a widely used organic semiconducting material, [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), has been utilized as a vibrational probe of molecular morphology in emerging electronic materials due to the sensitivity of its vibrational frequency to the local environment. Vibrational solvatochromic shift has been observed for dilute PCBM in organic solvents of varying polarity, but the spectral shift does not follow the order of solvent polarity, and its microscopic origin remains elusive. Here, we applied a mixed quantum/classical approach to simulate the infrared (IR) spectra for the ester carbonyl stretch of PCBM in dichloromethane, chloroform, and benzene. In this approach, the ester carbonyl group is treated quantum mechanically with a frequency map, and the rest of the system is described by molecular dynamics simulations. Based on the reasonable agreement with experimental IR spectra, we show that the specific directional interaction between the ester carbonyl group and its neighboring solvent molecules, which is not well captured by the solvent polarity, is primarily responsible for the observed solvatochromic shift. Furthermore, we find that the strength of this interaction also governs the solvation dynamics of the ester carbonyl group and the resulting frequency fluctuation, leading to a more inhomogeneously broadened spectrum for PCBM in chloroform compared to that in dichloromethane and benzene.
Study on propagation properties of electromagnetic waves through a magnetized, collisional and inhomogeneous plasma under oblique incidence
Authors: Mao Wangchen , Xu Guanjun
Published: August 2019

The properties of electromagnetic waves propagation through a collisional, magnetized and inhomogeneous plasma with obliquely incident angles are investigated in this paper. The reflection, transmission, and attenuation ratios are calculated first with the scattering matrix method. Based on the derived formulas, we then analyze the effects of different parameters on the propagation properties under oblique incidence. Simulation results indicate that a larger incident angle causes a longer wave transmission distance in the plasma and is more likely to impede the waves propagation. Under an obliquely incident angle, both the transmission and attenuation ratios are greatly affected by other parameters, such as the effective plasma collisional frequency, background magnetic flux density, plasma thickness and electron density, additionally. These conclusions are of guiding significance to the applications of the interaction between electromagnetic waves and plasma.
Colloidal quantum dots for infrared detection beyond silicon
Authors: Guyot-Sionnest Philippe , Ackerman Matthew M. , Tang Xin
Published: August 2019

This perspective describes the advantages of infrared colloidal quantum dots (CQDs) for photodetection beyond silicon and provides a brief review of the development of CQD photodetection. The standard specifications for photodetectors are listed with particular emphasis on the detectivity. High gain improves the responsivity but does not improve the detectivity, while nonradiative losses do not prevent high responsivity but limit the detectivity. Performances of CQD detectors and HgTe CQDs, in particular, are compared with the maximum possible detectivity based on detailed balance from the device temperature and nonradiative losses.
The role of yttrium modifying A357 alloy with sand casting
Authors: Mao Guoling , Zhu Congcong , Wang Shuai , Yan Han , Gao Wenli
Published: August 2019

The microstructure of A357 alloy modified by yttrium (Y) and its modification mechanism was investigated. The results show that under a sand casting condition, there was small or even no solution strengthening effect of Y on the A357 alloy. Y did not change the morphology of eutectic silicon but made it shorter, and Y increased the nucleation cores during its nucleation processes rather than promoting the formation of twinning during the growth processes. The solidification mode of many eutectic silicon phases changed from nucleating on the dendrites to heterogeneous nucleation of eutectic grains in the interdendritic liquid. The number and area of eutectic silicon clusters increased with increasing Y. A bright Al2Si2Y phase appeared even though Y was very low.
Improving the fretting performance of aero-engine tenon joint materials using surface strengthening
Authors: Lu Guoxin , Liu Huan , Lin Chaohui , Zhang Zheng , Shukla Pratik , Zhang Yongkang , Yao Jianhua
Published: August 2019

This paper summarises the regulation mechanism of the traditional and emerging surface strengthening treatments – mechanical shot peening (SP) and laser shock processing (LSP) treatment, respectively – on the fretting fatigue behaviour of the tenon joint materials of aero-engine cold-end parts, as surface strengthening treatment contributes to the improvement of service performance. From the point of view of the actual service environment of turbine components, this paper also expounds on the key problems faced by surface strengthening treatments in improving the mechanical properties of joint materials for aero-engine hot-end components. The application of LSP in the fretting fatigue life extension of turbine joint materials has strong feasibility and development prospects.
Young people and land in Zimbabwe: livelihood challenges after land reform
Authors: Scoones Ian , Mavedzenge Blasio , Murimbarimba Felix
Published: August 2019

This article explores the livelihood challenges and opportunities of young people following Zimbabwe's land reform in 2000. The article explores the life courses of a cohort of men and women, all children of land reform settlers, in two contrasting smallholder land reform sites. Major challenges to social reproduction are highlighted, reflected in an extended ‘waithood’, while some opportunities for accumulation are observed, notably in intensive agricultural production and agriculture-linked business enterprises. In conclusion, the implications of generational transfer of land, assets and livelihood opportunities are discussed in the context of Zimbabwe's agrarian reform.
How myosin II achieves total shutdown
Authors: Short Ben
Published: August 2019

JGP study describes 3-D structure of the 10S form of myosin II, identifying key interactions between the head and tail domains that keep the motor protein switched off.
The students’ metacognition analysis through jumping task based on lesson study for learning community
Authors: Saiful  , Susanto  , Hobri
Published: August 2019

This research aimed to analyze the students’ metacognition through jumping task based on lesson study for the learning community. This research is qualitative descriptive research. Data collection was done by observation, tests, interviews, think aloud and documentation. The test was given to students when an open class in class VIII of MTs Miftahul Hidayah. From the test results, students were grouped into three based on their level of ability. Two students were selected from each group to be interviewed and deepened through thinking aloud technique. Two students were selected from each group to be interviewed and deepened through thinking aloud technique. Data analysis is in the form of data induction and reduction theory. The results showed that students who had good metacognitive knowledge skills became effective and efficient when they were applying metacognitive control skills. Hence, the students who had poor metacognitive knowledge skills, they experienced difficulties when they were applying metacognitive control skills. The contribution of jumping tasks based on lesson study for learning community is very helpful in enhancing students’ metacognition abilities and skills to individually, in groups and classically.
The profile of student’s anxiety in solving the critical thinking problem on geometry according to Van Hiele theory
Authors: Ayu Cahyaningtyas Brenda , Sunardi  , Yuliati Nanik , Kusuma Dewi Arisna , Nikmatur Rohmah Fitriana
Published: August 2019

This research aimed at describing the students’ anxiety profile in solving the critical thinking problem on geometry according to Van Hiele theory. This research used descriptive type of research with qualitative approach. The methods used were test, observation and interview methods. The subjects were selected by using Van Hiele test. Van Hiele test was given to 100 students. Therefore, it obtained three levels that were the students of visualization level as much as 47%, the students of analysis level as much as 23% and the students of informal deduction level as much as 20%. The results of the critical thinking test on geometry revealed that the students of visualization level fulfilled the focus and inference indicators only while the anxiety on geometry found in the indicators of tensed-face, confusion, forgetful, poor concentration, anxiety and worry. The students of analysis level fulfilled the indicators of focus, reason, inference, situation and overview only while the anxiety on geometry found in the indicators of tensed-face, forgetful, anxiety and worry. Whereas, the students of informal deduction level reached all of the criteria of critical thinking while the anxiety on geometry found in the indicators of confusion, anxiety, impatient and easily disturbed.
The effectiveness of learning cycle with lesson study for learning community to build students creative thinking skills on algebraic form
Authors: Supriyanto  , Hobri  , Susanto  , Sahnawi  , Ursulasari Yuan
Published: August 2019

This research aims to describe the effectiveness of the learning cycle model (LC-5E) with Lesson Study for Learning Community (LSLC) to build students creative thinking skills in algebraic forms. The research procedures Consists of three stages: preparation of learning instruments, validation and revision, and the implementation of research. Data collection using Triangulation methods and creative thinking tests is based on The Torrance Test of Creative Thinking (TTCT). The data analysis shows that: the implementation of the lesson plan is very good category; the frequency of student activity that stands out is collaborative learning with positive responses to learning models; classical completeness of students algebraic ability are increase, creative thinking indicators achieved are fluency and flexibility, the not creative and less creative students are decrease, and the creative and very creative students are increase accompanied by growing collaborative learning and jumping task. Based on the results of data analysis, it was concluded that the implementation research is effective.
Contribution of a categorical statistical test in examining dependencies among qualitative variables by means simplification of correspondence analysis
Authors: Ginanjar I , Nurhuda I , Sunengsih N , Sudartianto
Published: August 2019

The contribution statistical test of categories to dependencies between qualitative variables is needed, because the existence of these categories will influence decision making. Decisions taken can be misleading, if a category does not contribute. If N is the matrix from 2×J or I×2 contingency table which is constructed from two qualitative variables, then the principal coordinates can be calculated using the simplification of correspondence analysis (SoCA). Principal coordinates produced by the SoCA are the same as conventional correspondence analysis (CA), but the SoCA presents a simpler calculation, because it is calculated directly from the elements of N. Principal coordinates derived from 2×J matrix N can be used to test the contribution of categories to dependencies between qualitative variables more simply, and obtained confidence intervals for each category.
Ethnomatematics : how does cigugur traditional community use palintangan on farming
Authors: Umbara Uba , Wahyudin  , Prabawanto Sufyani
Published: August 2019

This study discusses the way of Cigugur traditional community in Indonesia doing their calculating on farming. By using realist ethnography, this study reports objectively the information that collected from participant in the Cigugur traditional communitythrough observation, interviews, documentation, and field notes. The findings from this study show that the farming system carried out by the community used formal mathematics principles. The hari cycle and pasaran cycle in Sundanese are as the same as the concept of relations and functions in mathematics. The function in question is injective function. The results of the relations between day “hari” and “pasaran” can be expressed in an order pair to pair. To determine a finest day, the mathematical concepts used by the Cigugur traditional community are the concepts of addition and the concept of comparison. The sum concept is used to add the values of each day to the value of each pasaran. Meanwhile, the concept of comparison is used to compare the value of the sum results with the criteria for determining the finest day for tandur. Ethnomatematics provides different perspectives regarding mathematical conceptuality.
Spatial Data Panel Analysis for Poverty in East Java Province 2012-2017
Authors: Yolanda A M , Yunitaningtyas K , Indahwati
Published: August 2019

Poverty is a phenomenon of spatial heterogeneity, which is usually indicated by the tendency of poor people to group in a certain area. It means that poverty is influenced by the spatial effect. Geographical conditions and economic inequality that occurred in various regions in Indonesia, especially East Java reinforced the reason for adding spatial effects in the analysis. In addition, as an effort to obtain an increasingly accurate model, poverty that occurs is highlighted in a period of time. The aim of this study is to determine the factors that influence the percentage of poor people according to regency/city in East Java province in 2012-2017 by a spatial data panel analysis. The best model for this case is Spatial Autoregressive (SAR) model using the concept of distance. It shows that poverty in East Java is related to spatial effect. Therefore, each regency/city has different constants, depending on its spatial weighting matrix. Thus, the percentage of poor people by Regency/City in East Java province was influenced by Human Development Index (HDI), Poverty Gap Index (P1), Poverty Severity Index (P2) and also the spatial effect.
Fundamentals of horn antennas with low cross-polarization levels for radioastronomy and satellite communications
Authors: Miguel-Hernández J. De , Hoyland R.J.
Published: August 2019

The literature on horn antennas dedicated to radio astronomy and satellite communications applications is very extensive and at times disjointed, relevant contributions being distributed as far back as from the 60's until the present today. This work combines a compact but complete review of the different theories, methodologies and techniques used to describe corrugations and metamaterials in their application to feedhorns used in radio astronomy and satellite communications along with some new work to help explain the theory in a more practical way. Starting with the hybrid-mode condition firstly corrugated horns are explained describing soft and hard boundaries and also the theory from a plasmonic optics point of view. Following this the use of metamaterials in order to design horn antennas with quasi-null cross-polarization and low E-Plane sidelobes level over an ultra-wideband is described. The objective of this work is to help to ease the learning curve of the post graduate students and young professionals dedicated to these tasks, and try to inspire the work of the senior professionals toward a new direction and approach.
FEM-based assessment of wear of stamping die
Authors: Trzepiecinski T , Lemu H G
Published: August 2019

In sheet metal forming industry, surface damage and wear such as adhesion and ploughing of metallic sheet, is a well-known problem which reduces the tool life and quality of drawn elements. Surface defects are the consequences of wear and they accelerate the galling process. The knowledge of places particularly endanger wear allows appropriate design of tools. In this paper, an investigation that focused on the finite element-based analysis of wear of stamping tool for forming an axisymmetric drawpiece has been reported. The analyses were carried out for deep-drawing quality steel sheet with a sheet thickness of 2 mm. The basic mechanical parameters of the sheet tested are determined in uniaxial tensile tests. The analyses performed using Marc/Mentat program for nonlinear analyses take into account the strain hardening phenomenon of sheet material and different values of friction coefficient. The implementation of an Archard’s wear model in the numerical simulation proved the possibility of tool wear simulation in sheet metal forming. As a result of the conducted tests, the places of the stamping die potentially exposed to quick wear were determined. It was found that the most exposed region on accelerated wear is the upper part of the die radius.
Development of rapid qualitative detection DNA microarray platform for Salmonella typhimurium for food safety
Authors: Samphaongern C , Pipatpanukul C , Srikhirin T
Published: August 2019

Screening of possible bacteria contamination in food products is one of the measures implemented to avoid potential health hazards. In food industry, standard cell culture technique is widely used to monitor bacterial contamination. However, the main drawback of this technique is its inherited time consumed during the culturing step, which requires about 72 hours. In this research, an alternative DNA microarray technique was developed for a qualitative screening of a possible Salmonella typhimurium contamination in chicken, with the aim of reducing the detection time down to 3 hrs. The identification of S. typhimurium in food samples was carried out by hybridization of the possible contaminant with specific probe immobilized on a biochip. Novel DNA probes were designed as 16-50 base pairs of nucleotides to recognize with specific parts in S. typhimurium genomic. At least two DNA probes were identified as the candidate probes which had the potential to promote the best hybridization. DNA microarray was fabricated by mixing candidate DNA probes with photoactive polymer network, (poly(DMAA-mABP-SSNa)), and was printed onto a plastic substrate by non-contact microspotter. DNA probe was covalently immobilized onto the surface by 254 nm of UV lamp with 1.25 J/cm2. PCR product functionalized with biotin was hybridized with DNA probe and labelled with streptavidin-cy5. Specific binding yielded fluorescence signal. The intensity image signal was read-out by a fluorescent microarray reader. Two genes specific to S. typhimurium (fimC and invA), were investigated by using specially designed DNA primers and DNA probes. From the assay optimization, it was found that 1 mg/ml of polymer hydrogel concentration, 10 μM of DNA probe concentration, 10 μg/ml of labelling concentration, and 2 nL of array volume yielded the highest signal intensity. The results were calibrated into CFU/ml (cell forming unit). The system was applied successfully for the detection of S. typhiurium without any contamination. The biochip validation with spiked sample (DNA standard) is currently underway.
Effects of Sn Incorporation in ZnO Thin Films on Properties of Perovskite Solar Cells
Authors: Malison P , Bhoomanee C , Choopun S , Wongratanaphisan D , Sagawa T , Ruankham P
Published: August 2019

Properties of electron transporting layer (ETL) play an important role on photovoltaic performances of perovskite solar cells. In this work, effects of Sn incorporation on properties of ZnO-based perovskite solar cells were investigated. Sn-doped ZnO (TZO) thin film as ETL was prepared via a sol–gel method. With 5% atom doping, TZO film coated on an indium doped tin oxide (ITO) substrate provided comparable light transmittance with that of an undoped ZnO/ITO substrate. It was also found that the optical band gap of TZO film (3.30 eV) is slightly wider than that of the ZnO one (3.28 eV). These results suggest that Sn atoms probably incorporated into the ZnO crystal during the sol-gel method. The grains size of perovskite layer coated on TZO or ZnO films also showed variation. The perovskite crystal on the TZO thin film (average 300 nm) was larger than that of the one on ZnO thin film (average 277 nm). The preliminary results indicate that the perovskite solar cell based on TZO film provided higher power conversion efficiency (PCE) of 4.42 % than the ZnO-based device (3.16%). Short-circuit current density (J
sc), open-circuit voltage (V
oc) and fill factor (FF) of TZO-based device were also higher than the ZnO-based device. This may be because TZO film may provide lower resistivity and better ETL/perovskite interface contact, confirmed by lower series resistance and higher shunt resistance of the TZO-based device. Finally, this work introduced a simple method to prepare TZO film at low temperature for photovoltaic application. It may help guide the development of flexible solar cells and other optoelectronic devices.
Reduction of Endotoxin from Human Root Canals by Calcium Hydroxide Nanoparticles
Authors: Lungkapinth P , Louwakul P
Published: August 2019

This study was aimed to evaluate the reduction of endotoxin using the passive ultrasonic irrigation (PUI) of calcium hydroxide nanoparticles (CHNPs) compared with the PUI of calcium hydroxide (CH) and the CH medication. Forty-seven single-root human premolars were used. The root canals were enlarged and sterilized. Escherichia coli endotoxin was inoculated into the root canals. Thirty-six root canals were assigned into three experimental groups: CHNPs irrigation, CH irrigation, and CH medication. For the irrigation groups, the PUI was activated for three min. For the CH medication, the CH was filled into each canal and incubated at 37°C for seven days. The reduction of endotoxin was evaluated by quantitative chromogenic limulus amoebocyte lysate assay. Data was analysed by Kruskal-Wallis and pairwise comparison tests, with a level of significance set at P < 0.05. The CHNPs irrigation was more effective in against endotoxin than the CH irrigation (P < 0.05). No significant difference was found between the CHNPs irrigation and the CH medication (P > 0.05). The irrigation of CHNPs could eliminate most of the endotoxin from the root canals and approximately from 300 μm of root dentin. CHNPs might be potential as an adjunctive irrigation for endotoxin removal.
Biodegradation of Levan Polymer / Poly (Lactic Acid) (PLA) Blend
Authors: Phengnoi P , Thongmee K , Tiptipakorn S , Boekfa B , Kuttiyawong K
Published: August 2019

Poly (lactic acid) (PLA) is a biodegradable thermoplastic. With low elongation and poor degradation properties, many approaches have been developed to overcome these limitations, including copolymerization, blending and plasticizing to improve the mechanical properties. Levans are a group of fructan polymer with act as a good co-polymer, which can be produced by levansucrase using sucrose as substrate. In this study, co-solvent for levan/PLA blend film preparation, thermal properties and biodegradation of levan/PLA blend film were investigated. The result found that DMSO and CH2Cl2 were suitable for the co-solvent process. The Levan/PLA blend films were prepared with levan contents of 0, 0.5, 1, 2, 5, 10, 15 and 20 wt%. The biodegradation of levan/PLA blend film in vitro and in soil conditions showed that 15 wt% levan/PLA at 7 days and 10 wt% levan/PLA at 21 days were the highest weight loss, respectively. In addition, the morphological changes in the Levan/PLA blend film and thermal properties were analyzed by Scanning electron microscope (SEM) and Differential scanning calorimetry (DSC). The results from DSC present that the melting temperature of PLA was slightly decreased with increasing levan contents. Moreover, the holes from degradation were larger and the rougher surfaces were observed with levan contents.
Synthesis of Na-A zeolite from water treatment residue using hydrothermal and microwave techniques
Authors: Theptham B , Asavapisit S
Published: August 2019

Na-A zeolite was synthesized from water treatment residue (WTR) using hydrothermal and microwave techniques. WTR was brought from Metropolitan Waterworks Authority (Thailand) and was activated by firing at 700 °C for 3 h in an electric furnace. The activated WTR was reacted with 3 M NaOH solution in a reactor under a controlled temperature of 80, 90 and 100 °C for 8, 10, 12, and 14 h. SEM (Scanning electron microscopy) images reveal the cubic crystal of zeolite. The highest cation exchange capacity (CEC) was obtained from sample synthesized at 90 °C for 14 h and gave the CEC value of 3.14 meq/g Ca2+. For the microwave technique, the raw materials were reacted at 80 90 and 100°C for 30, 60, and 120 min. Results showed that the sample obtained at 80 °C for 30 min represented the highest CEC value of 0.29 meq/g Ca2+.
Thermal and Melting track Simulations of Laser Powder Bed Fusion (L-PBF)
Authors: Ninpetch P , Kowitwarangkul P , Mahathanabodee S , Tongsri R , Ratanadecho P
Published: August 2019

Laser powder bed fusion (L-PBF) process involves with the construction of phase transformation, melting, and rapid solidification of weld metal powder bed which affects the properties and the microstructure of final parts, e.g. density, dimension, mechanical properties, void, porosity, and non-fully melted particle. The aims of this work were to study the effect of process parameters, e.g. laser power and scanning speed, on the temperature field and melt pool geometry and the characteristics of single melting track in the L-PBF process by using the commercial CFD software simulation Flow-3D (Flow-weld). The laser power, scanning speed, laser spot diameter, and layer thickness varied in this study were 120 W, 140 W, 0.4 m/s, 0.6 m/s, 0.8 m/s, 80 μm and 50 μm respectively. The results stated that at the lower scanning speed, the temperature field has a region of heat distribution larger than that of the higher one. The geometry of melt pools can be changed from ellipse shape to tear drop shape when the scanning speed is increased. The width and depth of laser melting track is increased when the higher laser power and lower scanning speed are applied. The void is found underneath the laser melting track when the scanning speed changes from 0.4 m/s to 0.6 m/s.
Evaluation of silver -copper-tin brazing alloy corrosion behavior in chloride containing electrolyte at various temperature
Authors: Nurrochman A , Prajatelistia E , Cho K
Published: August 2019

Silver base brazing alloys are commonly used for brazing most of ferrous and nonferrous metals alloys. These families of filler metals have a lower brazing temperature due to Sn addition thus offers excellent flow. Meanwhile, the high content of Ag in the alloys guarantees a good corrosion resistance. However, the detrimental effect was shown when it joints in stainless steel. In present work, corrosion behavior of silver-copper-tin brazing alloy was evaluated. The brazing alloy was exposed to water contained chloride and the temperatures were varied at 25, 40, 55, and 70 °C. The electrochemical methods were utilized to evaluate the corrosion behavior of the alloy. The results showed that the dissolution of Sn seems to be initiating the corrosion of the silver-copper-tin brazing alloy. Nevertheless, the active dissolution of the Cu to the solution simultaneously influence the corrosion behavior of the silver-copper-tin brazing alloy. This study in terms of the alloy corrosion behavior in the particular environment should give both of academicals and industrials contributions.
The Performance of Permanent Magnet Core of Reducing Sag Voltage in Personal Computer (PC)
Authors: Ys H , Simanjuntak A D
Published: August 2019

The power quality has a significant effect on all system devices. The voltage factors are usually modulated caused by the excessive load changes which produce a sag voltage. One of the techniques used to reduce the voltage sag is to design a Cuk converter with PI controller coupled with two inductances (L) at the Cuk converter in order to make a non-ideal transformer with a permanent magnet core made by ferrite material. The experimental results revealed that, the non-ideal transformer with a permanent magnetic core would stabilizes the input voltage on personal computer (PC), thus the sag voltage can be minimalized. From the experiment, the optimum results were obtained with top gap was 1mm and the bottom gap was 6mm. It can be concluded that by using a ferrite core magnet with high coercivity, the output voltage can be stabilized thus there will be no sag at the input voltage on the PC.
Peptidomic and Bioinformatic Analysis to Evaluate the Application of Peptides from Latex of Hevea brasiliensis Clone BPM24
Authors: Havanapan P , Phungthanom N
Published: August 2019

Peptidomic analysis coupled with mass spectrometry identification was employed to investigate the constitutively expressed peptides in latex serum Phytophthora-resistant rubber tree (Hevea brasiliensis), BPM24. The utilization of proteins and peptides as a strategy to study new methods can lead to a therapeutic application. However, a high-efficiency method to extract peptides from latex serum is not well established. After optimization of latex serum isolation from natural rubber latex, using of lysis solution for peptide extraction exhibited superior serum peptide recovery than using other chemical reagents. Ultrafiltration followed by solid-phase extraction was selected to achieve high extraction yield of low molecular weight proteins and peptides. Mass spectrometric and bioinformatics analysis characterized and predicted the identified protein and peptide contents. All latex serum peptide fractions from C18 reversed-phase chromatography possessed effectiveness of antifungal activity against three tested plant fungal including A. brassicicola, C. lunata and M. grisea with different MIC in the range 250-2,000 μg/ml from different peptide fraction. Moreover, Etotal (E1-E5 pooled together) from lysis solution extraction was found to able to inhibit three tested plant fungal at MIC 500 μg/ml. Moreover, B. cereus and E. faecium were the sensitive gram-positive bacteria with MIC in the range 250-4,000 μg/ml. However, all gram-negative bacteria were not affected by 4,000 μg/ml. Among these tested pathogens, plant fungal was quite sensitive to our peptide product. Etotal from lysis solution extraction will be the best candidate for using further in antifungal testing of other plant fungal both in vitro and in vivo. The further investigation and application will lead to possible use of latex serum as a great biotechnological resource to develop peptide –based product for the treatment of plant infection.
Formulating policy recommendations for potential rubber plantation owners and rubber wood consumers in Thailand to obtain international forest management certification
Authors: Duangsathaporn K , Prasomsin P , Laemsak N , Omule Y , Palakit K , Lumyai P
Published: August 2019

The severity of environmental problems affecting air, soil, water, biodiversity, and forests, prompted relevant organizations to create mechanisms to prevent and manage these problems. One of these key mechanisms is Forest Certification, which is classified into two types, namely, Forest Management Certification (FM) and Chain of Custody Certification (CoC). The FM and CoC are certified by the relevant organization such as the Forest Stewardship Council (FSC) and the Programme for the Endorsement of Forest Certification (PEFC). These mechanisms will have an impact on the industry and commerce that use wood and tree products as a production base because of wood product importers may only import the certified products. This research project was designed to formulate policy recommendations for the potential development of rubber plantation owners and rubber wood consumers in Thailand to obtain international forest management certification. This was done using research data from two subprojects, namely, subproject 1: The analysis of rubber plantations on forest management certification status in Thailand, and subproject 2: Analysis of the factors affecting forest management certification of rubber plantations in Thailand. This resulted into four main policy recommendations in four broad areas: 1) Formulation of national policies and strategies to promote and access the forest certification systems for rubber plantation owners and rubber wood consumers; 2) Development of relevant organizations to promote and support forest certification in Thailand by determination and development of governmental organizations with the mission and potential in problem solving/negotiation and the potential developments of rubber plantation owners and rubber wood consumers for the whole system; 3) Development and availability of rubber plantation owners and rubber wood consumers in Thailand to obtain international certification; and 4) Research support in response to the development of forest certification in Thailand
Innovative Design of Latex Gloves Production Lines via Modular Industrial-sized Prototypes
Authors: Yongyingsakthavorn P , Chantrasmi T , Sriyubol T , Nimdum P , Tohsan A , Nontakaew U
Published: August 2019

An innovative design of continuous latex gloves production lines was introduced in work. A modular approach to the designing process was described and key technologies were identified. Based on these technologies, industrial-sized prototypes were constructed and tested. The objectives were largely to reduce the production cost by some means such as reducing the thermal energy usage, shortening the length production line and time and decreasing the number of stationed workers. As a proof of concepts, prototypes of drying oven and stripping machine were constructed and the vulcanization experiments were carried out. The results were promising, for instances, the new drying oven with outside chain was projected to be able to reduce the thermal energy loss by approximately 12% compared to the traditional design and the stripping machine was shown to be able to vertically remove latex gloves from formers while occupying less space and potentially using fewer workers. From the vulcanization experiment, it was shown that the vulcanization time could be significantly shortened by pre-vulcanization and drying process.
A game-theoretic model to select suitable rubber policy
Authors: Paoprasert N , Varasirikul T , Pichitlamken J
Published: August 2019

In this study, we used a game theoretic modelling technique to analyze the governmental policies by collecting natural rubber related data to create a model in order to select the policies that suit Thai rubber’s stakeholders. After the model has been created, we used sensitivity analysis to capture the uncertainties of parameters such as the success probabilities of the policies and the rubber price. The results from the game theoretic model show that there are two policies that should be selected by the government which is the policies that support the increase of natural rubber consumption by 10%-15%. However, in order for the government to optimally select these policies, the success rate of the policies needs to be at least 30%. Otherwise, none of the policies should be selected. Regarding the policy to support Tier-1 entrepreneurs, since the increase in demand by implementing this kind of policy is fairly small, the policy should not be chosen. The policy for Tier-2 companies owned by the local farmers should be supported when the chance of selling the products is more than 35%.
Research on Physics Stability of Emulsified Asphalt Modified by Nano Silica
Authors: Li Cong , Li Jie , Hu Yubo
Published: August 2019

At present, research on nano-modified asphalt and asphalt mixture has made some achievements. This article applies the stabilization mechanism of pickering emulsion to prepare emulsified asphalt, and uses nano silica particles as emulsifier. On this basis, we further investigate the physical stability of emulsified asphalt modified by nano silica through analyzing and studying the sieve residue and storage stability, and establish a solid basis for subsequent development and further research.
Effect of CeO2 on Enamel Coatings on the Surface of Corten Steel
Authors: Fan Chaozheng , Luo Lida , Wang Qingwei , Jiang Weizhong
Published: August 2019

Different amounts of CeO2 were added to the basic enamel formula, and preparation of enamel samples by two-burning method, the enamel coatings with different contents of CeO2 were characterized by acid resistance, IR, SEM and DSC. The results show that introduced CeO2, B-O-B vibration in [BO4] enhanced, acid resistance of ceramic layer increased. The introduction of CeO2 reduces the glass transition temperature of the enamel, while the high temperature viscosity of the porcelain glaze decreases, the surface of the porcelain layer becomes smoother, and the structure becomes denser after enamel sintered.
Preparation and Characterization of SiC/Al2O3 Composites
Authors: Yu Jinman , Wang Zhi , Wu Hao , Zhang Liu , Qi Fangfang , Zhang Xueqian , Liu Tongwei , Wang Xuye
Published: August 2019

The present research was focus on various SiC content adding to Al2O3 matrix to improve the mechanical properties of Al2O3 ceramic. The mechanical properties of the composites were characterized by XRD and SEM. The effect of SiC content on the mechanical properties of SiC/Al2O3 composites was studied. The results show that SiC/Al2O3 composites have the best comprehensive mechanical properties when the SiC content is 5vol.%. With the increase of SiC content, agglomeration phenomenon was obvious, pores at grain boundaries increased, fracture mode changed from transgranular fracture to intergranular fracture, and mechanical properties of the material got worse.
Fireproof Material Derived from Recycling Incinerator Ash Using Electric-Arc Technique
Authors: Yang Sheng-Fu , Wang To-Mai , Xu Qi-Zhen , Li Heng-Yi
Published: August 2019

In this study, municipal solid waste incinerator (MSWI) ashes were melted by electric-arc technique to produce man-made vitreous fiber (MMVF) using a fiber blowing method. The capacity of 50 kg/h at the pilot level was constructed to treat MSWI ashes and produce MMVF simultaneously. The fibrous derivatives were blended with cement to manufacture fireproof product. The MMVF produced in this work belong to short fiber which the characteristics are presented as follow: (1) fiber diameter range from 5.1 ± 1.2 μm; (2) shot content 6.3±0.8 wt.%; (3) fibrous length ranged from 0.3–3.5 cm. When the amount of MMVF added is at 43 wt.% in fireproof product, the density, porosity, fracture loading and flexural strength are 0.8 g/cm3, 66%, 42 kgf and 98.4 kgf/cm2, respectively. After a series of fireproof test, the fire resistant product had good performance on flammability and incombustibility characteristics. The fireproof product is stable and has satisfactory physical, mechanical and thermal properties.
Assessment of Typical Concrete Material Models used in Simulation of Concrete Slab under Blast in Air
Authors: Li Lingfeng , Tang Ting , Wei Zhuobin , Liu Jinghan , Zhang Yuanhao
Published: August 2019

To evaluate the suitability of three typical concrete material models, which are HJC material model, RHT material model and K&C material model respectively, in simulating concrete’s dynamic damage under air blast, a comparison between experiment observations and numerical simulation results is conducted. The three typical concrete material models are reviewed briefly at first. Then the experiment and numerical model information are presented. According to the comparison results, K&C material model shows the best suitability in simulating the damage mode of the concrete slab. RHT material model takes the second place for underestimating the concrete’s strength resistance. HJC material model, however, is no recommended for simulating concrete in such a situation.
Review on Thermal Conductivity of the Graphene Reinforced Resin Matrix Composites
Authors: Zhang Haiyun , Wang Danyong , Liu Juncong , Wei Huazhen , Liu Fangbiao , Xu Jingli , Li Shuhu , Qin Zhenming , Guo Jianfen , Wang Ronghui , Jia Huamin , Zhang Jianqin , Liu Yadong
Published: August 2019

Graphene is a two-dimensional nanostructure filler with high thermal conductivity (5000 W/mK) and excellent mechanical properties, which has a very wide application prospect. Graphene is with super high specific surface area, which provides a greater contact area with polymer matrix. Then it is more easy to form the thermal conductive heat channels, which could improve the thermal conductivity of composite materials. The concentration, the ratio of geometrical diameters, the dispersion in the matrix and the interfacial bonding between graphene and the matrix materials will greatly affect the thermal conductivity of graphene reinforced composites. However, the graphene nanosheets can be easy to stack together and difficult to be dispersed into the solvent and polymer matrix. In order to improve the interfacial combination between graphene nanosheets and the matrix so as to reduce the interfacial thermal resistance of the composites, it is usually to modify the surface of graphene nanosheets, which mainly includes non-covalent modification and covalent modification. In this paper, researches on the thermal conductivity of graphene were reviewed, and the existing problems and the future research focus were also discussed.
Corrosion Resistance of Hot-dip Zn55Al Coated Steel Sheet Treated by Cr(III) Conversion Coating Against Chloride-Containing Media
Authors: Pan Jie , Li Yan
Published: August 2019

Under the influence of chloride-containing environment such like shallow sub-marine or littoral area, hot-dip Zn55Al coated steel sheet is easily corrode. Based on an applicable combination of parameters, a Cr(III)-based conversion coating(TCC) was formed on Zn55Al coating successfully based on Coldip 120 commercial passivator. The corrosion behaviour of the Cr(III) treated hot-dipped steel samples subjected to the Cr(III)-based passivation treatment was studied using electrochemical impedance spectroscopy (EIS) in a 3.5% NaCl solution, and the failure mechanism of the conversion coating-hot-dip coating system was investigated by analysing the time dependence of the electrochemical parameters of impedance. In addition, the role of corrosion products formed on Zn55Al during the different immersion time in the NaCl solution was also revealed by scanning electron morphology (SEM) and energy dispersive spectrometer (EDS).
Optimizing Control for 20CrMnTiH(FQ) Bloom Internal Quality by EMS
Authors: Li H G , Chen T M , Chen L
Published: August 2019

Continuous casting EMS technology for 20CrMnTiH(FQ)gear steel bloom internal quality optimizing control was researched, based on the equipment of 360mmX450mm bloom casting machine conditions which is one factory of China. Ensure the install position of F-EMS which installed close at the end of liquid core by take numerical simulate calculation for the process of solidifying and heat transfer, measured the stirring magnetic field intensity(T), and carried out comparing experiment to find out the effects of stirring intensity on bloom internal quality, the optimal process parameters of combined EMS have been defined at last, taim to control 20CrMnTiH(FQ) gear steel bloom internal quality to be densify and homogenize have been realized.
Achieving Minimum Length Scale in Heaviside-based Morphological Filters
Authors: Qie Longfei , Jing Shikai , Lian Ruichao , Wang Lei
Published: August 2019

Minimum length scale can fulfil the requirements for manufacturing and provide the extended robustness of design performance. This paper proposes a method to impose the minimum length scale in Heaviside-based morphological filters. With the method, the physical filter radius is first utilized to construct the element neighbourhood in density filter. Then, the density filter is embedded in the Heaviside filter and modified Heaviside filter. Finally, the morphological filters are constructed based on the principles of morphology-based restriction schemes, in which the Heaviside filter plays the role of dilation filter and the modified Heaviside filter acts as the erosion filter. Test results show that the minimum structural sizes in the final design are larger than the specified filter radius size. The characteristics of the basic filters and the embedded filters are discussed.