bluuebunny/crossref_metadata_2025 huggingface dataset:
The Optical Properties of Nano-Materials and Electromagnetic Wave Propagation Visualized with MATLAB
Authors: Ma Ye Wan , Wu Zhao Wang , Liu Quan Jin , Sheng Yong Cai , Zhang Li Hua , Yin Xun Chan , Zhan Shen Bao
Published: July 2018

The course of electromagnetic fields and waves has properties of abstract concept, strong theory and complex calculation, thus this course is difficult to study and understand, and then is also difficult to teach. In order to make the understanding of the course easier, MATLAB software is used as a platform in classroom teaching of electromagnetic fields and waves. This paper mainly discusses the electrical field intensity distribution of media sphere materials and the properties of electromagnetic wave propagation with MATLAB software. The optical properties of dielectric-metal core-shell multi-layered nano-shell are also studied with Laplace's equation. To enrich the teaching content and improve a better teaching effect, the optical property of nano-materials and electromagnetic wave propagation are visualized with MATLAB software, which makes the properties of nano-materials and electromagnetic wave propagation understand easily.
Synthesis and Optical Properties of Dipolar Thiazole Derivatives Incorporating Nitro and Amino Substituents
Authors: Aisyah Ahmad Shah Noor , Pairan Nur Farahin , Kasim Noor Azilah Mohd , Yamin Bohari Mohd
Published: July 2018

We report the synthesis of two dipolar thiazole derivatives functionalized with nitro group as electron acceptor and amino group as electron donor, in order to study their optical properties in the UV-vis range. Their structures were verified by 1H NMR, 13C NMR, HRMS and FT-IR. The resulted thiazole derivatives have good thermal stability with decomposition temperature, Td of 320.20 °C and 284 °C for compounds 1 and 2 respectively. The absorbance bands of compound 2 in the UV-vis range are more red-shifted than that of compound 1 which made compound 2 could have high potential as a great organic NLO material.
The Growth of (00l)-Oriented CeO2 Buffer Layers on R-Cut Sapphire Substrates for the Epitaxy of Tl-2212 Superconducting Films
Authors: Chen Ming Xian , Zhao Xin Jie , Jiang Yan Ling , Ji Lu , Tang Ping Ying , Huang Guo Hua , Xie Qing Lian
Published: July 2018

Tl-2212 superconducting films were fabricated on r-cut sapphire substrates buffered with (00l)-oriented CeO2films. The buffer layers were deposited by the cerium dioxide sputtering target and the RF magnetron sputtering method. The epitaxial growth of CeO2films on r-cut sapphire substrates was obtained over a wide range of sputtering parameters, such as temperature, pressure, power and Ar/O2ratio. The Tl-2212 films grown on these buffer layers subsequently were purely c-axis orientation. The critical transition temperature of the best film was 105.6 K, the critical current density was 2.8 MA/cm2(77 K, 0 T) and the surface resistance was 435 μΩ (10 GHz, 77 K).
Experimental Study on the Corrosion Behavior of Produced Fluid on J55 Steel during CO2 Flooding
Authors: Zhao Jin Sheng , Ju Ying Jun , Tang Mei Rong , Chen Rong Huan
Published: July 2018

CO2 flooding has been widely used in oil field development, but the produced fluid is easy to cause corrosion of tubing and casing. In order to determine the corrosion behavior of produced fluid on J55 steel during CO2 flooding, we use the simulated oil well produced fluid as corrosive medium and conduct the corrosion simulation experiment at high temperature and high pressure. The experimental results showed that the crystalline grain size of corrosion film surface is different for the different CO2 partial pressure. When CO2 partial pressure is greater than the critical pressure, the crystalline grain is not oblique six-party crystal structure, and the grains become small and compact, so the corrosion product film should have a good corrosion inhibition. Both static and dynamic corrosion of samples are serious. The research has a theoretical guiding significance on corrosion protection during CO2 flooding.
Grain Size Effect on Saddle Phenomenon in V-Bending Process of Thin Sheet Metal
Authors: Chen Chang Cheng , Hong Yi Xiang
Published: July 2018

The ability for predicting the springback on sheet metal bending processes is identified as an important feature of the ability for predicting the final geometry of sheet metal parts. The grain size effect makes the difficult on application of traditional design method in processing. As through tool and processing design, to understand the effects of grain size effects is an important and powerful way to effectively compensate for and eliminate the springback. In this paper, 99.5% pure iron specimens were annealed at different temperature to obtain the specified grain sizes. The effects of different grain sizes on the saddle after V-bending of the thin sheet metal were investigated. The results show that at the same thickness of specimens, the grain size has no significant effect on the saddle height. However, with increasing the thickness of the specimens the saddle will also be more prominent protruding height. The concave side of bent specimen is against the compression force and its grains structure tend to a round shape, whereas the convex side is against the tensile force and its grains structure tend to a flaky shape.
Research of Urban Rail Transit Vehicle Aluminum Alloy Bolster FSW Welding Technology Based on Thermal-Mechanical Coupling
Authors: Sun Ying Shi
Published: July 2018

With the rapid development of urban rail transit and the increasing level of research and development, aluminum alloy materials feature excellent physical and mechanical properties, and thus an urban rail transit vehicle adopts aluminum alloy materials. Friction Stir Welding (FSW) technology is adopted in the production process of a bolster in this article and research of stress strain of friction stir welding parts plays an important role for engineering application of friction stir welding technology.
Multi-Objective Optimization of Surface Roughness and Cutting Forces in Hard Milling Using Taguchi and Response Surface Methodology
Authors: Vu Ngoc Chien , Huang Shyh Chour , Nguyen Huu That
Published: July 2018

Cutting forces and surface roughness are important output parameters affecting the machining performance and quality of any machined surface in hard milling. In order to obtain the best surface quality and highest productivity, the input-cutting parameters need be considered and chosen properly whenever hard milling is involved. Therefore, in this paper, an attempt is made to conduct the multi-objective optimization of the surface roughness (Ra) and the resultant cutting force (Ft) in hard milling of SKD61 steel by Taguchi method and Response Surface Methodology (RSM). Values of the input parameters for milling tests are chosen through the stability lobe diagram of a machine tool simulated by the use of Cutpro software. The Taguchi method is used for designing all of the milling experiments. The values of Ra and Ft are measured by a Surftest SJ-400 and a dynamometer, respectively, and then analysis of variance is conducted to find out the effect of machining process conditions on Ra and Ft. In order to get the low Ft and Ra, a multi-objective optimization is implemented with the use of the desirability function. The results reveal that the optimized machining conditions for Ra and Ft are a cutting speed of 100 m/min, a feed rate of 0.015 mm/tooth, and a depth of cut of 0.44 mm, with predicted Ra of 0.206 µm and Ft of 66.58 N.
Flow Characteristics of Microscale Porous Media with Varying Porosity and Pore Size
Authors: Lee Jun Sik
Published: July 2018

Sintered porous media are considered to be one of the best candidates to cool high temperature gas turbine components with blades and vanes for next-generation air cooling. The sintered porous media used in this study is made of the stainless steel SUS316L by metal injection molding process. The complex interaction between fluid and the porous medium causes fluid pressure drop when the fluid is forced to flow through the porous surface. In addition, the information on the relation between porosity and pressure drop of the porous media is important to saving the costs of the filter application and cooling process. This research is intended to understand flow characteristics of the porous media with the air fluid movement according to different porosity and pore size for gas turbine application. The experimental data compared with the calculation are examined for different experimental conditions, which indicate flow behavior of erratic and compressible on the microscopic scale porous media.
A Properties of Concrete using LCD Waste Glass Subjected to Sulfate Attack
Authors: Kim Gyeom Boo , Jang Il Young , Kim Seong Kyum , Lee Kwang Woon
Published: July 2018

In this study, it investigated the micropore changes by aging of LCD waste glass powder and investigated the effects of particle size and replacement ratio on sulfate erosion. Also, the comparison of the compressive strength with that of OPC concrete was carried out to evaluate the sulfate resistance of the LCD waste glass mixed concrete. As a result, resistance to sodium sulfate is better than magnesium sulfate.
Study of the Torsional Behavior of Aluminum Foam-Filled Galvanized Steel Tubes after High Temperature
Authors: Wang Zhan Guang , Wang Yang
Published: July 2018

Torsional test of aluminum foam-filled galvanized steel tube before and after high temperature is performed. The influence of temperature, porosity of aluminum foam and steel ratio on torsional behavior of aluminum foam galvanized steel tubes were analyzed. Experimental results showed that torsional curves of aluminum foam-filled galvanized steel tube before and after high temperature is similar, and can be divided into four stages: the elastic torsional stage, yield platform stage, descent stage and hardening stage; Its torsional load capacity decreases with increasing porosity of aluminum foam and increases at a higher steel content and slenderness ratio; after high temperature, torsional load capacity of galvanized steel tube decreased significantly. It was found that the strength reduction factor ratio under the elevated test temperature is higher than that recommended by British ECCS, Australian AS4100 and Chinese CECS 200-2006.
Synthesis of High Molecular Weight Poly(L-Lactic Acid)s by Direct Polycondensation with Organic Acids as Catalyst
Authors: Hwang Sung Yeon , Oh Dong Yeop X. , Park Je Young
Published: July 2018

In this study, high molecular weight (HMW) poly (l-lactic acid)s (PLLAs) were synthesized by direct polycondensation using organic acid catalysts alone in a nitrogen-controlled environment. The melting point and enthalpy of the pre-polymer produced by melt polycondensation increased as molecular weight grew during solid-state polycondensation. It was observed that the nitrogen-controlled external environment had lower molecular weight than air, but the low molecular weight tail was significantly reduced, as indicated by gel permeation chromatography. This is because it inhibited the reverse reaction by preventing the penetration of water inside the reactor. Also, the control of moisture improved the color of PLLA. The amount of organic acid catalyst used was 1 wt%, which was favorable for achieving HMW. Both p-toluenesulfonic acid and 4-ethylbenzenesulfonic acid are examples of organic acids that were able to produce HMW PLLA.
Failure Analysis of High Pressure Container using Fractography and Material Morphology
Authors: Kim Eui Soo
Published: July 2018

High-pressure gas containers must be able to withstand high internal pressures because they store compressed gases. Otherwise, cracks or defects may lead to an explosion, which may in turn lead to a large-scale disaster. Therefore, accurate analysis of the causes of cracks or defects and various techniques for detecting cracks or defects are needed. In this research, we analyzed the failure mechanism of a high-pressure gas container through fractography using scanning electron microscopy and optical microscopy and through measurements of their mechanical and chemical properties.
Cryogenic Compressive Strength and Thermal Deformation of Reinforced Polyurethane Foam Material for Membrane Type LNG Carrier
Authors: Song Chang Yong , Cho Doo Yeoun
Published: July 2018

LNG carrier is purposed to transport a liquefied LNG cargo which is reduced to 1/600 of volume in temperature condition of -163°C. In the context of structural performance on LNG cargo hold, the mechanical and thermal behaviors of insulation material under cryogenic temperature are considered as one of the critical factors for the hold design. This paper deals with the thermal deformation and the compressive strength of the reinforced polyurethane foam (RPUF) adapted for the insulation material of membrane type LNG carrier via both material tests and numerical simulations realizing the cryogenic condition. The material tests related to the thermal deformation are carried out to investigate the characteristics for thermal transfer on the actual RPUF specimen. The heat transfer simulations based on finite element analysis (FEA) are carried out using forced convection theory. The results of heat transfer analyses are compared to the material test results. Reasonable cryogenic conditions on RPUF are reviewed from both the analyses and the test results. In the regard of static material strength for the RPUF, the compressive material tests are carried out. The cryogenic temperature effect on the compressive strength of RPUF is evaluated by comparing to the room temperature material test results. From the compressive material tests, the effect of temperature on the ultimate compressive strength is investigated with variation of elongation.
The Physical Properties of PMMA Denture base Resin Incorporated with Vanillin
Authors: Vongvachvasin Kittituch , Thaweboon Sroisiri , Churnjitapirom Pornkiat , Kaophun Saowaros , Chotprasert Natdhanai
Published: July 2018

Long-term use of a denture base can be a reservoir of microbes due to porosities and mechanical wear of denture surfaces. Vanillin has an antimicrobial effect. However, its influence on physical properties after incorporated in PMMA has not yet been evaluated. The purpose of this study was to investigate physical properties of PMMA by incorporating vanillin in different concentrations. Material and method. There were three groups of PMMA with ten specimens per group. Flexural strength and flexural modulus were tested by using a 3-point bending machine, and surface hardness was determined by Vickers hardness test. One-way ANOVA and Kruskal Wallis tests were used to analyze all data at 0.05 significance level. Result. The 0.1% vanillin group yielded a significant difference in Vickers hardness number (17.15 HV) as compared to 0.5% vanillin group (16.30 HV) and without vanillin (15.30 HV). In contrast, the flexural strength and modulus showed no significant difference among test groups upon incorporation of vanillin. Conclusion. The vanillin incorporated PMMA group demonstrated higher surface hardness, compared to the group without vanillin. In addition, there were no significant differences in flexural strength and flexural modulus among the three groups. This study also found no adverse effect in physical properties of the vanillin incorporated PMMA.
Novel Rice Gel for Ultrasound Applications: Physical and Chemical Properties
Authors: Punyanitya Sittiporn , Koonawoot Rungsarit , Thiensem Sakdiphon , Punyanitya Warangkul
Published: July 2018

Novel rice gels were prepared with different compositions of rice starch (RS) powder and solution of additives. The formulations of gels were composed of RS powder, liquid glycerol, and additives by aqueous solution method. Five solution with different concentration of RS powder (0.5 g, 1 g, 1.5 g, 2 g and 2.5 g). These solutions were dried in electric oven at 65°C for 4 hours. The physical and chemical properties of rice gel characterized were: turbidity, viscosity, smell, irritation, cleaning, pH and moisture content of these gels have been monitored. Results showed that 2 g of RS powder was optimized formulation which had turbidity, high viscosity, pleasant smell, non-irritation and easy to clean. The pH value of this gel was 6.92 ± 0.01 and the moisture content was 0.21 ± 0.07 % which was equivalent to commercial standard of ultrasound gel. These results concluded that the application of RS in gel ultrasound was safe and effective for replacement commercial gel ultrasound. This gel should be studied on image quality in ultrasound examination next step.
Removal of Pb2+, Cu2+, Ni2+, Cd2+ from Wastewater using Fly Ash Based Geopolymer as an Adsorbent
Authors: Onutai Sujitra , Kobayashi Takaomi , Thavorniti Parjaree , Jiemsirilers Sirithan
Published: July 2018

This work aims to evaluate the effectiveness of fly ash based geopolymer powder as an adsorbent for heavy metals in aqueous solution. The structure of synthesized geopolymer was found to be highly amorphous due to the dissolution of fly ash phase. Moreover, the fly ash geopolymer powder has higher surface area compares to original fly ash with specific surface area of 85.01 m²/g and 0.83 m2/g, respectively. For this reason, the geopolymer powder has much higher removal efficiency compared to the original fly ash powder. The removal efficiency was affected by contact time, geopolymer amount, heavy metal initial concentration, pH, and temperature. The four heavy metals were chosen (Pb2+, Cu2+, Ni2+, Cd2+) for adsorption test. The highest heavy metal removal capacity was obtained at pH 5. The geopolymer powder adsorbed metal cations in the order of Pb2+>Cu2+>Cd2+>Ni2+. In addition, Langmuir model is more suitable for fly ash geopolymer powder adsorption of heavy metal ions in aqueous solution than Freundlich model. The results showed that the fly ash geopolymer powder has high efficiency for removal metal which could be employed excellent alternative for wastewater treatment.
Indirect Electrochemical Reduction of Indigo and Dyeing
Authors: Tan Xiao Dong , Xiong Wei , Zhang Jin , Xu Jie , Yi Chang Hai
Published: July 2018

The method of electrochemical reduction utilizes electrons as agent to achieve the reduction of indigo, vat dyes and pollution emissions, as well as the recycling of electrolyte. In this study, Ca2+-Fe3+-triethanolamine (TEA) redox system was used as the mediator to achieve the indirect electrochemical reduction of indigo. The optimization of parameter was analyzed by reduction efficiency (RE) and current efficiency (CE). The result showed that indigo could be reduced by electrochemical method and the best optimization recipe was 20 g/L NaOH + 5 g/L Fe2(SO4)3 + 30 g/L TEA + 5 g/L Calcium gluconate + 3 g/L indigo in 1 A·dm-2 current density at 50°C. This work suggested that Ca2+-Fe3+-TEA redox system in reduction of indigo was an effective way with higher CE (75.9 %).
Date Palm Fiber Reinforced High Density Polyethylene Composites: Effect of Fiber Loadings on the Melt Rheological Behavior
Authors: Chafidz Achmad , Augustia Venitalitya , Zulkania Ariany , Subagyo Asmanto , Kaavessina Mujtahid , Rizal Muhammad
Published: July 2018

In the recent years, the trend of using renewable source (green) fillers in the composites fabrication is increasing. One of these green fillers is natural fibers, which referred to the plant fibers, such as date palm fiber (DPF). In the present work, high-density polyethylene (HDPE)/DPF composites have been prepared. Four different DPF loadings were used (i.e. 0, 5, 10, 20 wt%) to prepare the composites. The effect of DPF loadings on the melt rheological behavior of the HDPE/DPF composites were studied. The melt rheological test results showed that both of storage modulus (Gʹ) and loss modulus (Gʺ) increased with the increase of DPF loadings. Additionally, the Han plot showed an upward shift from neat HDPE (i.e. DFC-0) to DFC-20, which indicated that the melt rheological properties changed with the increase of DPF loadings. The complex viscosity |h*| of the composites samples also increased with the increase of DPF loadings. The increased was more significant at higher DPF loadings (i.e. DFC-20). Meanwhile, the Carreau-Yasuda model was found to be well fitted with the experimental data.
Effects of Poly(Methyl Methacrylate)-Encapsulated Nanosilica on Mechanical Properties of Poly(Lactic Acid)/Ethylene Vinyl Acetate Nanocomposites
Authors: Pongkasem Jasmine , Chuayjuljit Saowaroj , Chaiwutthinan Phasawat , Larpkasemsuk Amnouy , Boonmahitthisud Anyaporn
Published: July 2018

In this study, poly(lactic acid) (PLA) was melt mixed with three weight percentages (10–30wt%) of ethylene vinyl acetate copolymer (EVA) in an internal mixer, followed by a compression molding. According to a better combination of mechanical properties, the 90/10 (w/w) PLA/EVA was selected for preparing hybrid nanocomposites with three loadings (1, 3 and 5 parts per hundred of resin , phr) of poly(methyl methacrylate)-encapsulated nanosilica (PMMA-nSiO2). The nanolatex of PMMA-nSiO2 was synthesized via in situ differential microemulsion polymerization. The obtained PMMA-nSiO2 showed a core-shell morphology with nSiO2 as a core and PMMA as a shell, having an average diameter of 43.4nm. The influences of the EVA and PMMA-nSiO2 on the impact strength and the tensile properties of the PLA/EVA nanocomposites were studied and compared. It is found that the impact strength and the tensile properties of the 90/10 (w/w) PLA/EVA were improved with the appropriate amounts of the EVA and PMMA-nSiO2.
Effect of Date Palm Fiber Loadings on the Mechanical Properties of High Density Polyethylene/Date Palm Fiber Composites
Authors: Augustia Venitalitya , Chafidz Achmad , Setyaningsih Lucky , Rizal Muhammad , Kaavessina Mujtahid , Al Zahrani Saeed M.
Published: July 2018

The trend of using natural fibers as green filler in the fabrication of polymer composites is increasing. One of these natural fibers is date palm fiber (DPF). Date palm fiber is considered as agricultural waste in certain areas, such as Middle East countries. Therefore, the utilization of this fiber in the composites fabrication is an interesting topic of research. In the current study, composites were prepared by melt blending DPF with high density polyethylene (HDPE). Five different DPF loadings were studied (i.e. 0, 5, 10, 20, 30 wt%). The effect of the DPF loadings on the mechanical properties and water absorption behavior of the composites were investigated. The tensile test result showed that tensile strengths of all the composites samples were all higher than the neat HDPE with the maximum improvement was achieved at the DPF loading of 5 wt% (i.e. DFC-5), which was about 19.23 MPa (138% higher than the neat HDPE). Whereas, the flexural test result showed that the flexural strength of the composites slightly increased compared to that of the neat HDPE only until 5 wt% DPF loading (i.e. DFC-5). Afterward, the flexural strength of the DFC-10 was equal to that of the neat HDPE, and decreasing with further increase of DPF loadings. Additionally, the water absorption test result showed that the water absorption rate and uptake of water (at equilibrium) increased with the increase of DPF loading.
On transfer operators on the circle with trigonometric weights
Authors: Chen Xianghong , Volkmer Hans
Published: July 2018

We study spectral properties of the transfer operators

L

defined on the circle

\mathbb T=\mathbb R/\mathbb Z

by

(Lu)(t)=\frac1 d\sum_{i=0}^{d-1} f\Big(\frac{t+i}{d}\Big)u\Big(\frac{t+i}{d}\Big),\quad t\in\mathbb T

where

u

is a function on

\mathbb T

. We focus in particular on the cases

f(t)=|\cos(\pi t)|^q

and

f(t)=|\sin(\pi t)|^q

, which are closely related to some classical Fourier-analytic questions. We also obtain some explicit computations, particularly in the case

d=2

. Our study extends work of Strichartz [11] and Fan and Lau [3].
Determination of the walk dimension of the Sierpiński gasket without using diffusion
Authors: Grigor'yan Alexander , Yang Meng
Published: July 2018

We determine the walk dimension of the Sierpiński gasket without using diffusion. We construct non-local regular Dirichlet forms on the Sierpiński gasket from regular Dirichlet forms on the Sierpiński graph whose suitable boundary is the Sierpiński gasket.
Dual bases in Temperley–Lieb algebras, quantum groups, and a question of Jones
Authors: Brannan Michael , Collins Benoît
Published: July 2018

We derive a Laurent series expansion for the structure coefficients appearing in the dual basis corresponding to the Kauffman diagram basis of the Temperley–Lieb algebra TL

_k(d)

, converging for all complex loop parameters

d

with

|d| > 2\cos\big(\frac{\pi}{k+1}\big)

. In particular, this yields a new formula for the structure coefficients of the Jones–Wenzl projection in TL

_k(d)

. The coefficients appearing in each Laurent expansion are shown to have a natural combinatorial interpretation in terms of a certain graph structure we place on non-crossing pairings, and these coefficients turn out to have the remarkable property that they either always positive integers or always negative integers. As an application, we answer affirmatively a question of Vaughan Jones, asking whether every Temperley–Lieb diagram appears with non-zero coefficient in the expansion of each dual basis element in TL

_k(d)

, when

d \in \mathbb R \backslash \big[-2\cos\big(\frac{\pi}{k+1}\big),2\cos\big(\frac{\pi}{k+1}\big)\big]

. Specializing to Jones–Wenzl projections, this result gives a new proof of a result of Ocneanu [27], stating that every Temperley–Lieb diagram appears with non-zero coefficient in a Jones–Wenzl projection. Our methods establish a connection with the Weingarten calculus on free quantum groups, and yield as a byproduct improved asymptotics for the free orthogonal Weingarten function.
Зануление старших когомологий линейных расслоений на обобщенных разрешениях Спрингера
Authors: Hu Yue
Published: July 2018

В данной работе гипотеза, выдвинутая Финкельбергом и Ионовым, доказывается с помощью обобщенной версии разрешения Спрингера и теоремы Грауэра-Рименшнайдера о занулении. Как следствие получается, что коэффициенты обобщенных функций Костки от многих переменных, введенные Финкельбергом и Ионовым, неотрицательны.
О суммах по Минковскому большого числа малых слагаемых
Authors: Roginskaya Maria Martinovna , Shul'man Viktor Semenovich
Published: July 2018

Доказано, что слабо замкнутое подмножество банахова пространства является выпуклым тогда и только тогда, когда его можно представить в виде суммы множеств сколь угодно малого диаметра.
Аффинность энтропии Арова
Authors: Gurevich Boris Marcovich
Published: July 2018

В работе продолжается изучение исторически первого варианта динамической энтропии, предложенного в дипломной работе Д. З. Арова и оставшегося практически незамеченным. Основной результат состоит в том, что энтропия Арова, подобно энтропии Колмогорова-Синая, обладает свойством аффинности. Это, в частности, позволяет строить разнообразные примеры динамических систем, в которых энтропия Арова не определяется энтропией Колмогорова-Синая.
The Control of Typhoid Fever in Vietnam
Authors: Nga Tran Vu Thieu , Duy Pham Thanh , Lan Nguyen Phu Huong , Chau Nguyen Van Vinh , Baker Stephen
Published: July 2018

Typhoid fever, caused by Salmonella enterica serovar Typhi (S. Typhi), is a diminishing public health problem in Vietnam, and this process may represent a prototype for typhoid elimination in Asia. Here, we review typhoid epidemiology in Vietnam over 20 years and assess the potential drivers associated with typhoid reduction. In the 1990s, multidrug resistant S. Typhi were highly prevalent in a sentinel hospital in southern Vietnam. A national typhoid incidence rate of 14.7/100,000 population per year was estimated around the new millennium. The Vietnamese government recognized the public health issue of typhoid in the 1990s and initiated vaccine campaigns to protect the most vulnerable members of the population. At their peak, these campaigns immunized approximately 1,200,000 children in 35 provinces. Concurrently, Vietnam experienced unprecedented economic development from 1998 to 2014, with the gross national income per capita increasing from $360 to $1,890 over this period. More recent typhoid incidence data are not available, but surveillance suggests that the current disease burden is negligible. This trajectory can be considered a major public health success. However, a paucity of systematic data makes it difficult to disaggregate the roles of immunization and water, sanitation, and hygiene (WASH) interventions in typhoid reduction in Vietnam. Given the limitations of typhoid vaccines, we surmise the practical elimination of typhoid was largely driven by economic development and improvement in general population living standards. Better designed WASH intervention studies with clinical endpoints and systematic incidence data are essential to glean a greater understanding of contextual factors that impact typhoid incidence reduction.
Estranged but not strangers: Challenging organisational norms of access for people with disability and people from a NESB
Authors: Bamford Vicki A
Published: July 2018

This research investigates organisations' ability to be inclusive. It seeks to isolate the conditions necessary for inclusion of the organisation's publics who identify with disability and who come from a non-English speaking background given they can be estranged. This is achieved through a case study of a service organisation that is obliged to engage with its publics and has a strategy to do so. Data were gathered from the organisation's documentation and interviews with instigators of policies and processes. Feedback from the organisation's clients was collected, focusing on their experience of being engaged and included given norms of inclusion may not be shared. A thematic analysis was undertaken of the data to isolate themes on inclusion. Themes revealed: a culture of inclusion; a policy that encouraged an exchange; and processes established by professionals with expertise to design and promote inclusion beyond their usual publics.
Whither Standpoint Theory In A Post-Truth World?
Authors: Paradies Yin
Published: July 2018

This paper begins with a brief overview of the origins and continued use of standpoint theory in the social sciences. It highlights both historical and contemporary challenges to the utility of standpoint theory as a critical scholarly tool, including developments such as intersectionality and transgenderism / transracialism. Specifically, the implications of a post-truth era for standpoint theory are considered alongside the affective turn, purity politics and the critique of critique. Given the slow, but steady, erosion of the ivory tower in which academics enjoyed privileged access to ‘truth’, this paper concludes with the need to foster scholar activism via new forms of knowledge politics that move beyond existing approaches to standpoint theory.
The secondary formation of organosulfates under interactions between biogenic emissions and anthropogenic pollutants in summer in Beijing
Authors: Wang Yujue , Hu Min , Guo Song , Wang Yuchen , Zheng Jing , Yang Yudong , Zhu Wenfei , Tang Rongzhi , Li Xiao , Liu Ying , Le Breton Michael , Du Zhuofei , Shang Dongjie , Wu Yusheng , Wu Zhijun , Song Yu , Lou Shengrong , Hallquist Mattias , Yu Jianzhen
Published: July 2018

Abstract. Organosulfates (OSs) with ambiguous formation mechanisms are a potential source of missing secondary organic aerosol (SOA) in current atmospheric models. In this study, we chemically characterized OSs and nitrooxy-OSs (NOSs) formed under the influence of biogenic emissions and anthropogenic pollutants (e.g., NOx, SO42−) in summer in Beijing. An ultrahigh-resolution mass spectrometer equipped with an electrospray ionization source was applied to examine the overall molecular composition of S-containing organics. The number and intensities of S-containing organics, the majority of which could be assigned as OSs and NOSs, increased significantly during pollution episodes, which indicated their importance for SOA accumulation. To further investigate the distribution and formation of OSs and NOSs, high-performance liquid chromatography coupled with mass spectrometry was employed to quantify 10 OSs and 3 NOS species. The total concentrations of quantified OSs and NOSs were 41.4 and 13.8 ng m−3, respectively. Glycolic acid sulfate was the most abundant species among all the quantified species, followed by monoterpene NOSs (C10H16NO7S−). The total concentration of three isoprene OSs was 14.8 ng m−3 and the isoprene OSs formed via the HO2 channel were higher than those formed via the NO ∕ NO2 channel. The OS concentration coincided with the increase in acidic sulfate aerosols, aerosol acidity, and liquid water content (LWC), indicating the acid-catalyzed aqueous-phase formation of OSs in the presence of acidic sulfate aerosols. When sulfate dominated the accumulation of secondary inorganic aerosols (SIAs; sulfate, nitrate, and ammonium; SO42− ∕ SIA > 0.5), OS formation would obviously be promoted as the increasing of acidic sulfate aerosols, aerosol LWC, and acidity (pH < 2.8). Otherwise, acid-catalyzed OS formation would be limited by lower aerosol acidity when nitrate dominated the SIA accumulation. The nighttime enhancement of monoterpene NOSs suggested their formation via the nighttime NO3-initiated oxidation of monoterpene under high-NOx conditions. However, isoprene NOSs are presumed to form via acid-catalyzed chemistry or reactive uptake of oxidation products of isoprene. This study provides direct observational evidence and highlights the secondary formation of OSs and NOSs via the interaction between biogenic precursors and anthropogenic pollutants (NOx, SO2, and SO42−). The results imply that future reduction in anthropogenic emissions can help to reduce the biogenic SOA burden in Beijing or other areas impacted by both biogenic emissions and anthropogenic pollutants.
Long-term Lidar Observations of the Gravity Wave Activity near the Mesopause at Arecibo
Authors: Yue Xianchang , Friedman Jonathan S. , Zhou Qihou , Wu Xiongbin , Lautenbach Jens
Published: July 2018

Abstract. 11-years long K Doppler lidar observations of temperature profiles in the mesosphere and lower thermosphere (MLT) between 85 and 100 km, conducted at the Arecibo Observatory, Puerto Rico (18.35° N, 66.75° W), are used to estimate seasonal variations of the mean temperature, the squared Brunt-Väisälä frequency, and the gravity wave potential energy in a composite year. The following unique features are obtained: (1) The mean temperature structure shows similar characteristics as a prior report based on a smaller dataset: (2) The profiles of the squared Brunt-Väisälä frequency usually reach the maxima at or just below the temperature inversion layer when that layer is present. The first complete range-resolved climatology of potential energy of temperature fluctuations in the tropical MLT exhibits an altitude dependent combination of annual oscillation (AO) and semiannual oscillation (SAO). Between 88 to 96 km altitude, the amplitudes of AO and SAO are comparable, and their phases are almost the same and quite close to day of year (DOY) 100. Below 88 km, the SAO amplitude is significantly larger than AO and the AO phase shifts to DOY 200 and after. At 97 to 98 km altitude, the amplitudes of AO and SAO reach their minima, and both phases shift significantly. Above that, the AO amplitude becomes greater. The annual mean potential energy profile reaches the minimum at 91 to 92 km altitude. The altitude-dependent SAO of the potential energy is found to be highly correlated with the satellite observed mean zonal winds reported in the literature.
Data inversion methods to determine sub-3 nm aerosol size distributions using the particle size magnifier
Authors: Cai Runlong , Yang Dongsen , Ahonen Lauri R. , Shi Linlin , Korhonen Frans , Ma Yan , Hao Jiming , Petäjä Tuukka , Zheng Jun , Kangasluoma Juha , Jiang Jingkun
Published: July 2018

Abstract. Measuring particle size distribution accurately down to approximately 1 nm
is needed for studying atmospheric new particle formation. The scanning
particle size magnifier (PSM) using diethylene glycol as a working fluid has
been used for measuring sub-3 nm atmospheric aerosol. A proper inversion
method is required to recover the particle size distribution from PSM raw
data. Similarly to other aerosol spectrometers and classifiers, PSM inversion
can be deduced from a problem described by the Fredholm integral equation of
the first kind. We tested the performance of the stepwise method, the kernel
function method (Lehtipalo et al., 2014), the H&A linear inversion method
(Hagen and Alofs, 1983), and the expectation–maximization (EM) algorithm.
The stepwise method and the kernel function method were used in previous
studies on PSM. The H&A method and the expectation–maximization algorithm
were used in data inversion for the electrical mobility spectrometers and the
diffusion batteries, respectively (Maher and Laird, 1985). In addition, Monte
Carlo simulation and laboratory experiments were used to test the accuracy
and precision of the particle size distributions recovered using four
inversion methods. When all of the detected particles are larger than 3 nm,
the stepwise method may report false sub-3 nm particle concentrations
because an infinite resolution is assumed while the kernel function method
and the H&A method occasionally report false sub-3 nm particles because
of the unstable least squares method. The accuracy and precision of the
recovered particle size distribution using the EM algorithm are the best
among the tested four inversion methods. Compared to the kernel function
method, the H&A method reduces the uncertainty while keeping a similar
computational expense. The measuring uncertainties in the present scanning
mode may contribute to the uncertainties of the recovered particle size
distributions. We suggest using the EM algorithm to retrieve the particle
size distributions using the particle number concentrations recorded by the
PSM. Considering the relatively high computation expenses of the EM
algorithm, the H&A method is recommended for preliminary data analysis. We
also gave practical suggestions on PSM operation based on the inversion
analysis.
The mirror mode: a “superconducting” space plasma analogue
Authors: Treumann Rudolf A. , Baumjohann Wolfgang
Published: July 2018

Abstract. We examine the physics of the magnetic mirror mode in its final state of
saturation, the thermodynamic equilibrium, to demonstrate that the mirror
mode is the analogue of a superconducting effect in a classical
anisotropic-pressure space plasma. Two different spatial scales are
identified which control the behaviour of its evolution. These are the ion
inertial scale λim(τ) based on the excess density
Nm(τ) generated in the mirror mode, and the Debye scale
λD(τ). The Debye length plays the role of the correlation length
in superconductivity. Their dependence on the temperature ratio
τ=T‖/T⟂<1 is given, with T⟂ the reference temperature
at the critical magnetic field. The mirror-mode equilibrium structure under
saturation is determined by the Landau–Ginzburg ratio
κD=λim/λD, or
κρ=λim/ρ, depending on whether the Debye length
or the thermal-ion gyroradius ρ – or possibly also an undefined
turbulent correlation length ℓturb – serve as correlation
lengths. Since in all space plasmas κD≫1, plasmas with λD
as the relevant correlation length always behave like type II
superconductors, naturally giving rise to chains of local depletions of the
magnetic field of the kind observed in the mirror mode. In this way they
would provide the plasma with a short-scale magnetic bubble texture. The
problem becomes more subtle when ρ is taken as correlation length. In
this case the evolution of mirror modes is more restricted. Their existence
as chains or trains of larger-scale mirror bubbles implies that another
threshold, VA>υ⟂th, is exceeded. Finally,
in case the correlation length ℓturb instead results from
low-frequency magnetic/magnetohydrodynamic turbulence, the observation of
mirror bubbles and the measurement of their spatial scales sets an upper
limit on the turbulent correlation length. This might be important in the
study of magnetic turbulence in plasmas.
Recent changes to the hydrological cycle of an Arctic basin at the tundra–taiga transition
Authors: Krogh Sebastian A. , Pomeroy John W.
Published: July 2018

Abstract. The impact of transient changes in climate and vegetation on the hydrology of
small Arctic headwater basins has not been investigated before, particularly in the
tundra–taiga transition region. This study uses weather and land cover
observations and a hydrological model suitable for cold regions to investigate historical
changes in modelled hydrological processes driving the streamflow response of
a small Arctic basin at the treeline. The physical processes found in this
environment and explicit changes in vegetation extent and density were
simulated and validated against observations of streamflow discharge, snow
water equivalent and active layer thickness. Mean air temperature and
all-wave irradiance have increased by 3.7 ∘C and 8.4 W m−2,
respectively, while precipitation has decreased 48 mm (10 %) since 1960.
Two modelling scenarios were created to separate the effects of changing
climate and vegetation on hydrological processes. Results show that over
1960–2016 most hydrological changes were driven by climate changes, such as
decreasing snowfall, evapotranspiration, deepening active layer thickness,
earlier snow cover depletion and diminishing annual sublimation and soil
moisture. However, changing vegetation has a significant impact on decreasing
blowing snow redistribution and sublimation, counteracting the impact of
decreasing precipitation on streamflow, demonstrating the importance of
including transient changes in vegetation in long-term hydrological studies.
Streamflow dropped by 38 mm as a response to the 48 mm decrease in
precipitation, suggesting a small degree of hydrological resiliency. These
results represent the first detailed estimate of hydrological changes
occurring in small Arctic basins, and can be used as a reference to inform
other studies of Arctic climate change impacts.
Identification and classification of urban micro-vulnerabilities in tsunami evacuation routes for the city of Iquique, Chile
Authors: Álvarez Gonzalo , Quiroz Marco , León Jorge , Cienfuegos Rodrigo
Published: July 2018

Abstract. Many coastal cities around the world are threatened by tsunamis;
some of these events have caused great impacts in recent times. The loss of
human lives during these events is the main cause of concern of the
authorities, and evacuation planning has been recognized as one of the best
tools for safeguarding the population. In this context, urban design appears
to be critical for the execution of prompt and efficient evacuation processes
to safe areas; however, evacuation assessment has been traditionally carried
out at a large urban scale, mostly taking into consideration urban morphology
and connectivity. In the present work, urban spaces available for tsunami
evacuation are explored in detail by developing a methodology to identify and
classify urban micro-vulnerabilities that may reduce the capacity of the
evacuation routes and hinder evacuees' safety. The method is applied to the
Chilean city of Iquique, affected by an earthquake and subsequent tsunami in
2014.
Development and validation of the Terrain Stability model for assessing landslide risk during heavy rain infiltration
Authors: Gutiérrez-Martín Alfonso , Herrada Miguel Ángel , Yenes Gallego José Ignacio , Castedo Ruiz Ricardo
Published: July 2018

Abstract. Slope stability is a key topic, not only for engineers but also for politicians, due to the considerable monetary and human losses that landslides can cause every year. In fact, it is estimated that landslides have caused thousands of deaths and economic losses amounting to tens of billions of euros per year around the world. The geological stability of slopes is affected by several factors, such as climate, earthquakes, lithology and rock structures, among others. Climate is one of the main factors, especially when large amounts of rainwater are absorbed in short periods of time. Taking into account this issue, we developed an innovative analytical model using the limit equilibrium method supported by a geographic information system (GIS). This model is especially useful for predicting the risk of landslides in scenarios of heavy unpredictable rainfall. A hydrological steady-state assumption was incorporated into this approach. The model, called Terrain Stability (TS), was developed and programmed in MATLAB. This model allows a simulation of the slope stability in a 2D spatial distribution. Many variables measured in the field – topography, precipitation, type of soil – can be added, changed or updated using simple input parameters. To validate the model, we applied it to a real example, that of a landslide which resulted in human and material losses (collapse of a building) at Hundidero, La Viñuela (Málaga) in February 2010.
Corporate Disclosure: A Synthesis of Literature
Authors: Modugu Kennedy Prince
Published: July 2018

This study is a compendium of the existing literature on corporate disclosure with a view to identifying the gaps to which future empirical inquiry may be directed. The paper discusses the concept of disclosure as canvassed by different authors. This review is initiated with a working definition of disclosure. This was followed by a series of reviews of studies in developed countries. Added to this, are developing countries’ studies. The review showed that the influencers of corporate disclosure differ between developed and developing countries on the one hand, and within both economies on the other hand. The review revealed mixed findings on the determinants of corporate disclosure. This suggests that the factors determining corporate disclosure are not fixed, and vary from one jurisdiction to another. The paper also x-rays a litany of theories of corporate disclosure research and suggests a unified theory that amalgamates the existing theories; and that which will be amenable to the ever-changing reporting environment.
Dinámica poblacional de insectos plagas en el cultivo del plátano (Musa paradisiaca L.) en Rivas, Nicaragua
Authors: Castillo Arévalo Trinidad , Jiménez-Martínez Edgardo
Published: July 2018

El cultivo del plátano en Nicaragua es un rubro de alta rentabilidad y con aceptables índices de producción y calidad, representa un producto alternativo de mucha importancia en el departamento de Rivas. La seguridad que este cultivo proporciona a los pequeños, medianos y grandes productores se ha visto amenazada por un conjunto de plagas y enfermedades que afectan a la planta y sus frutos. Con el objetivo de contribuir al conocimiento científico sobre los principales insectos plagas asociados al cultivo del plátano (Musa paradisiaca. L), se realizó este estudio en el periodo comprendido de Enero a Septiembre del 2014 en seis fincas plataneras del departamento de Rivas. Para este estudio se realizaron muestreos de insectos picudos usando trampas de discos de cormos de plátano, para muestrear insectos en hojas de plátano, se muestrearon las hojas bajeras de 25 plantas por finca. Los insectos encontrados en el estudio fueron identifi cados en el laboratorio de entomología de la Universidad Nacional Agraria, estos fueron Cosmopolites sordidus, Methamacius hemipterus, Rhinchosporum palmarum y Dysmicoccus grassi. Los meses de mayo a septiembre son el periodo donde se encontró mayor presencia de estos insectos comparado con los meses de verano de enero a abril donde las poblaciones de estos insectos fueron menor.