bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of inoculum size, inducer and metal ion on lipase production by Rhodococcus strain UCC 0009
Authors: Nallapan Maniyam Maegala , Sundarajoo Anupriya , Hazwan Azman Hazeeq , Suhaila Yaacob Nor , Abdullah Hasdianty
Published: November 2020

Lipases are critical enzymes for industrial applications such as in the food and pharmaceutical fields. Therefore, the discovery of new lipases with enhanced characteristics are always encouraged. Thus, the present study explored the ability of a novel bacterial strain isolated from a tropical climate for lipase production. The optimization method using the one-variable-at-a-time approach was adopted to obtain increased production of lipase. The strain identified as Rhodococcus strain UCC 0009 was able to generate specific lipase activity of 11.67a ± 0.00 mU/mg at optimized conditions of 8 % (v/v) inoculum concentration, 1 % (v/v) olive oil as the inducer, and the addition of Ca2+ions. The specific lipase activity increased by 162 % when the optimization using a one-variable-ata-time approach was adopted compared to that of the non-optimized counterpart, signifying this experimental phase’s importance. The present study’s findings revealed the potential of utilizing Rhodococcus strain UCC 0009 as a green lipase producer for application in bioremediation and biotransformation at an industrial scale. Further study concentrating on enzyme characterization and improving culture conditions for conducive production of lipase via statistical optimization using response surface methodology (RSM) will be attempted to elucidate further the superiority of lipase obtained from local resources.
The design of slow sand filter with a media of silica sand and granular activated carbon to eliminate iron, manganese, and fecal coliform contents for the Faculty of Nursing in Universitas Indonesia’s CWPS
Authors: Wasistoadi Budiarto Adrian , Tsania Fairuz , Gusniani Irma , Hartono Djoko M.
Published: November 2020

The Faculty of Nursing of Universitas Indonesia in Depok uses groundwater as the source of clean water in a large amount: 2.115.240 liters in 2018 and 22.010.960 liters in 2019. One of the alternatives for reducing groundwater use is to utilize surface water in the surrounding area of the campus, such as Lake Agathis. For the lake water to be used as the source of clean water, it needs to be processed first using a clean water provision system (CWPS). The CWPS is designed to contain two slow sand filter units, with the media consisting of 60 cm-thick silica sand and 40 cm-thick granular activated carbon in each unit. The CWPS is also equipped with one unit of shore intake, two units of suction well, one transmission duct, one unit of disinfectant and reservoir, and two filter media cleaning units. Based on a literature review from several journals and the results from this experiment, the designed slow sand filter with the previously determined thickness can reduce iron contents by 95,07%, manganese contents by 97,09%, and fecal coliform contents by 99%. The designed CWPS can serve the needs of clean water of the faculty described before with a debit of 3,8 L/s until the year 2042.
Preparation of nickel manganese oxide modified ni foam for anode catalyst direct urea fuel cell
Authors: Yolanda Yola , Ridwan Muhammad , Wook Hong Jong , Anggarainum Ivandini Tribidasari
Published: November 2020

Renewable energy is known as environmentally friendly, such as fuel cells. Nickel is regarded as one of the most promising transition metals to be applied as an electrocatalyst in fuel cell application due to its high catalytic activity. However, the modification of nickel is required to decrease its overpotential. In the present study, the NiMn2O4/Ni-foam was prepared for an anode catalyst in the direct urea fuel cell. The NiMn2O4/Nifoam was synthesized through the hydrothermal method at 180°C for 24 h using Mn(NO3)2.6H2O and Ni(NO3)2.6H2O solutions as the precursors in the presence of urea. During the reaction, Ni foam was placed in the solution to undergo the reaction inside the porous of the Ni-foam. Cyclic voltammetry of the prepared NiMn2O4/Ni-foam electrode in a 2 M KOH solution and 0.33 M urea showed good maximum current density at 206 mA cm-2. Furthermore, the prepared electrode was examined in a direct urea fuel cell with a solution containing 2 M KOH and 0.33 M urea in the anode chamber and a solution containing 2 M H2O2 and 2 M H2SO4 in the anode chamber. A power density of 0.304 mW cm-2 was achieved, indicating the prepared electrode is promising to be developed for a catalyst in a direct urea fuel cell.
Pesticide use data for emission modelling: A case study on the Upper Citarum River Basin
Authors: Utami Rosetyati R. , Geerling Gertjan W. , Salami Indah R.S. , Notodarmojo Suprihanto , Ragas Ad M.J.
Published: November 2020

Information on pesticide use types and pesticide use are needed to estimate pesticide emissions in the surface water. Unfortunately, these data is either limited or even non-exist in most lowand middleincome country like Indonesia. This problem is considered a missing link in the water monitoring system, especially in the emission estimation model approach. To overcome that problem, a questionnaire survey about pesticide use by the farmer was conducted in the Upper Citarum River Basin (UCRB) agriculture area. The survey result showed that 31 pesticides were used by farmers in UCRB, with pesticide type of insecticide (58%) as the most used by the farmers. Overall, Profenofos and Mancozeb had the widest used in UCRB. For rice crops, as the broadest agriculture area in UCRB, Carbamates and Pyrethroid-based insecticides such as Carbofuran and Deltamethrin were the most frequently mentioned pesticides of the farmers. The variation in application frequency influenced the amount of pesticide use for each crop. In general, the frequency of pesticide application for vegetables was higher (from 7-10 times/ month) than rice and tubers (≤ 1 time/ month).
State of the art preliminary literature review: Sustainability and waste reporting capabilities in management systems
Authors: Happonen Ari , Minashkina Daria
Published: November 2020

Inspired by previous studies research gap findings and limitations in management system functions to produce sustainabilityrelated reporting authors set a goal to map the current academic literature in the context of waste management systems. The method chosen for the work was a systematic literature review, focusing on the Web of Science and Scopus databases. The authors found a total of 115 unique publications from the selected databases, which were filtered 28 contributing studies. With these studies, this study found that most of the publications are journals and almost half of the work has been published in the last 3 years. Additionally, sustainability and waste management reporting related literature seem to enjoy wide appreciation among the peers, indicated by a high number of references these publications had gathered. As an overall finding, the specific research area of waste management process quantified data reporting seems really young overall and needs additional research with multiple research gaps clearly waiting for follow-up research to pinpoint the specific areas to contribute in the near future.
Digital age business model innovation for sustainability in University Industry Collaboration Model
Authors: Happonen Ari , Santti Ulla , Auvinen Harri , Räsänen Teemu , Eskelinen Tuomo
Published: November 2020

This study aims to investigate a digitalization-related business model as a result from the university-SME collaboration. The SME of the case study (Preventos Informatics Ltd) specializes in water distribution systems in industrial scale, telemetry, and sensor data-based monitoring of the water distribution. The business model of the company is a result of an innovation process during 2016-2017. The SME was established 2018. This study examines the commercialization process’s success factors and compares the original business model to the finally implemented one after two years. The study reviews the current literature of sustainable business models and digitalization and reflects the results from this study. Based on the results, by quantifying the sustainability, environmental aspects and digitalization, value added can be brought to the business model. Our study suggests that by adding more digitalization, sensor technologies, and dataanalysis, quantifying the real value of innovations is possible.
Constrain of smallholder forest management on timber legality assurance system (SVLK) certification: A case study in KTH Enggal Mulyo Lestari, Ponorogo District, East Java Province
Authors: Dara Tri Puspita Purbasari Dinar , Karuniasa Mahawan , Mahardhito Adhitya Wardhana Yuki
Published: November 2020

Timber Legality Assurance System or Sistem Verifikasi Legalitas Kayu (SVLK) is implemented and recognized as a certification for timber products exported from Indonesia. SVLK applied to all the forest product chains included the smallholder Forest Management Unit (FMU). It has been a particular concern to smallholder FMU on achieving the compliance of SVLK at least at two points: 1) the capability and knowledge for the technical process; and 2) the challenges to meet the certification cost. Researches have been done on the capability, challenges and opportunity, cost and benefit, strategies, and how the absence of smallholders FMU certification on supply chain affected timber product legality uncertainty. Meanwhile, a concern on smallholder FMU’s willingness to pay (WTP) certification as one of the main constraints of SVLK implementation is still unseen. A case study in KTH Enggal Mulyo Lestari aims to reveal the actual willingness to pay to fulfill the SVLK certification cost. Research conducted by Focus Group Discussion followed by a questionnaire. This study’s findings illustrate that the WTP of smallholders FMU is still under the certification costs minimum standard stipulated on regulation. Some partnerships with the wood industries, local government and non-government organizations are suggested in this article.
Generating high-quality training data for atomic neural networks with virtual reality
Authors: Kim Meeri
Published: November 2020

Virtual reality allows users to manipulate and create low-dimensional molecular structures that can be input as training data to predict the energies of larger, complex molecular systems.
A method for directly counting and quantitatively comparing aggregated structures during cluster formation
Authors: Yang Xi , Lu Zhong-yuan
Published: November 2020

Assembling of a few particles into a cluster commonly occurs in many systems. How-ever, it is still challenging to precisely control particle assembling, due to the various amorphous structures induced by thermal fluctuations during cluster formation. Although these structures may have very different degrees of aggregation, a quantitative method is lacking to describe them, and how these structures evolve remains unclear. Therefore a significant step towards precise control of particle self-assembly is to describe and analyze various aggregation structures during cluster formation quantitatively. In this work, we are motivated to propose a method to directly count and quantitatively compare different aggregated structures. We also present several case studies to evaluate how the aggregated structures during cluster formation are affected by external controlling factors, e.g., different interaction ranges, interaction strengths, or anisotropy of attraction.
Electric field induced charge migration and formation of conducting filament during resistive switching in electrochemical metallization (ECM) memory cells
Authors: Roy Arijit , Cha Pil-Ryung
Published: November 2020

Although it has been commonly accepted that resistive random access memories (ReRAMs) operate by exploiting the electric field to form or break the conducting filaments (CFs), the formation of CF still remains elusive and so is the correlation of physiochemical properties with electrical responses. Using the phase field model, we show the complete correlation between the physiochemical process driven CF formation and the electrical responses in ReRAM systems, specifically in the electrochemical metallization (ECM) memory cells. We could qualitatively validate all the unique I–V characteristics (associated with CF formation) available in the experimental literature for inorganic as well as hybrid organic–inorganic ReRAM systems. We believe that the universal description and the obtained qualitative validation of the model could shape the future ReRAM research where the formation of CF plays the dominant role.
Broadband bandgap and shock vibration properties of acoustic metamaterial fluid-filled pipes
Authors: Hu Bing , Zhang Zhenfang , Yu Dianlong , Liu Jiangwei , Zhu Fulei
Published: November 2020

This paper describes the design of an acoustic metamaterial fluid-filled pipe with periodically variable materials. The aim of this design is to improve the broadband vibration attenuation frequency range of fluid-filled pipes by combining the mechanism of local resonance (LR) and Bragg scattering bandgaps (BGs). The vibration bandgap (BG) of the pipe is investigated using the transfer matrix method. It is demonstrated that the coupling of LR and Bragg scattering BGs produces a remarkable improvement in effective bandwidth. Additionally, the external shock excitation effect on pipe vibration is calculated using the finite element method. This indicates that the strongest interaction between the LR and Bragg BG is achieved when the LR is located in the center of the softer material. However, this strong coupling effect may cause some degeneration in the Bragg BG. Moreover, in practical applications, the position of the LR BG should be determined according to the vibration BG requirements. Experimental samples are prepared, and an experimental test and verification procedure is conducted. The positions and widths of the BG and the shock vibration properties measured during the experiment agree well with the theoretical results. This research provides a technical and theoretical basis for the attenuation design of vibration reduction systems for fluid-filled pipes that may be subjected to explosive loads.
Abrupt change in domain switching behavior within tetragonal phase regime of (x)Na1/2Bi1/2TiO3-(1 − x)K1/2Bi1/2TiO3
Authors: Adhikary Gobinda Das , Ranjan Rajeev
Published: November 2020

We show that the lead-free piezoelectric system (x)Na1/2Bi1/2TiO3-(1 − x)K1/2Bi1/2TiO3 [xNBT-(1 − x)KBT] exhibits a boundary within its tetragonal phase regime at 0.58 < x < 0.60 across which the system exhibits an abrupt increase in reversible domain switching and high-field electrostrain for x > 0.58. We demonstrate that the abrupt changes, mimicking a composition-driven phase transition like scenario, are due to a sudden increase in the structural disorder for x > 0.58.
Corrigendum to: Filling gaps in the biology and habitat use of two spurdog sharks (Squalus japonicus and Squalus brevirostris) in the East China Sea
Authors: Yano Toshikazu , Ohshimo Seiji , Sakai Takeshi , Yoda Mari
Published: November 2020

The conservation and management of sharks requires appropriate information on their biological and habitat characteristics. Data needed for the conservation and management of two dominant demersal shark species in the East China Sea, the spurdogs (Squalus japonicus and Squalus brevirostris), are inadequate. To remedy this, we analysed biological, catch and abiotic data from bottom trawl surveys conducted in 2000–05 and 2008–14 from within the East China Sea. The precaudal length of male and female S. japonicus at 50% sexual maturity was 396.1 and 459.9mm respectively, whereas for S. brevirostris it was 289.6 and 354.9mm respectively. Prey overlap was high between species, with lanternfishes the most important prey. The fractional trophic level was 4.33 for S. japonicus and 4.31 for S. brevirostris. We estimated spurdog habitat using a generalised additive model. Depth affected the presence of both sharks, with latitude also affecting the presence of S. brevirostris. These two spurdog species were spatially segregated over the continental slope, and body-length and sex-ratio distributions suggested that there was a maturity-based segregation within and among species. The results of this study improve our understanding of the population dynamics of these spurdog species, their reproduction and diet, fundamental information required for their conservation and for improved fisheries management.
Different cultural conceptualizations underlying intercultural business communication problems between Thais and
Koreans
Authors: Hyun Yangwon
Published: November 2020

When people from different cultural backgrounds interact, their divergent conceptualizations may result in
communication problems. While the significance of intercultural business interactions between Thais and South Koreans has
increased with the development of trade relations between their countries, few attempts have been made to research interactional
problems in this context. This study investigates the respective Thai and Korean cultural conceptualizations that underlie
communication problems between them in the context of Korean multinational companies operating in Thailand. By analyzing data
derived from in-depth interviews, this article elucidates the linguistic features of Thai and Korean speakers in relation to four
different culture-specific conceptualizations: for Thais, the cultural schema of kreng jai and the cultural
category of phinong; and for Koreans, the cultural schemas of ppalli ppalli and
gunsinyuei. The findings show that these cultural conceptualizations govern Thais’ and Koreans’ different
ways of interacting, and the paper discusses how these differences lead to and shape misunderstandings and interpersonal conflicts
between these cultural counterparts during intercultural business communications.
The importance of cultural conceptualizations and metacultural competence in developing cultural literacy
Authors: García Ochoa Gabriel , Normand-Marconnet Nadine , McDonald Sarah
Published: November 2020

Cultural Literacy is an emerging, interdisciplinary approach in literary and cultural studies. As such, it seeks to grow and benefit from different fields and disciplines. Whilst there are differences between Cultural Literacy and Cultural Linguistics, there is common ground between them, and Cultural Literacy can draw immense benefit from the cross-pollination of ideas with Cultural Linguistics. This article explores the interconnections between Cultural Literacy and Cultural Linguistics, particularly in relation to intercultural communication. The article compares a number of differences and similarities between Cultural Linguistics and Cultural Literacy, in particular, the notions of ‘cultural conceptualisations’ and ‘metacultural competence’ as they are currently applied in Cultural Linguistics. The article discusses the possible use of cultural conceptualisations in Cultural Literacy, arguing that these can support the development of cultural literacy skills, by providing a strong, useful framework to enhance what is known as ‘cultural readability’. Furthermore, the paper looks at the application of strategies for metacultural competence hitherto associated with Cultural Linguistics in the context of Cultural Literacy, arguing that such strategies illustrate practical steps that can be taken toward developing an individual’s Cultural Literacy skills. Lastly, the article suggests that the ideas of transcultural competence, critical reflection and cultural readability, often used in Cultural Literacy, can enrich new discussions on Cultural Linguistics.
“Say Mashallah!”
Authors: Algharabali Nada , Taqi Hanan
Published: November 2020

The goal of the present study is to investigate the sociolinguistic aspects in relation to the existence of the evil eye
as a belief system in Kuwaiti society. Specifically, we examine the verbal and nonverbal manifestations of the evil eye, even at a distance,
when its effect is believed to permeate into online interaction on social media. To achieve this goal, we used a combined research method
that consists of an online questionnaire that reached an extensive group of 518 participants and a face-to-face interview with a group from
our sample in order to elicit both quantitative and qualitative data. The results demonstrate that believing in the evil eye and its harmful
effects is prevalent among all groups of people in the Kuwaiti society, regardless of sociolinguistic factors, which affect the frequency
and nature of posts. Our findings also indicate that the same verbal and nonverbal methods of protection from the evil eye used in the
offline world are used online. Moreover, these preventative methods appear to be in support of similar ones mentioned in previous literature
related to this area.
Euphemisms as linguistic tool for politeness in Kempo speech of Manggarai
Authors: Semiun Agustinus
Published: November 2020

This article presents euphemisms as linguistic tools for the expression of politeness in a local language, Kempo speech of
the Manggarai language, in West Flores, Indonesia. The universal use of euphemisms indcates that speakers of languages across the world very
much care about politeness as a means to maintain social relationships. Euphemisms are defined as the use of soft or mild words to replace
offensive words for the purpose of politeness. They are used during interactions, to ensure that social relationships are maintained. The
qualitative data show that Kempo ethnic people use various types of mild words to prevent their crops being damaged by certain animals; to
maintain interactions by not mentioning certain human body parts; to replace the names of certain professions that are not polite to mention
during interactions; and to avoid mentioning unworthy words for certain activities, events, and conditions. These euphemisms are used to
maintain politeness in any interaction or communication.The euphemisms identified are morphologically and syntactically formed. It is
interesting that some euphemisms are in the form of words bearing lexical meanings, while others have idiomatic meanings. Meanwhile, some
euphemisms are in phrase and clause forms that bear idiomatic meanings. These findings indicate that the people of Kempo ethnicity very much
care about how to use language properly to maintain politeness and social relationships.
Facilitative transfer only?
Authors: Guo Yanyu , Yuan Boping
Published: November 2020

This study investigates transfer effects and later development in English-Cantonese bilinguals’ L3 Mandarin grammar. Three
types of Mandarin sentence-final particle clusters are involved as the target structures. The results show that L3 learners with the
knowledge of Cantonese behave in a less native-like way than their English-speaking L2 counterparts on the illicit Mandarin cluster
[*de le/* le de] that has a licit corresponding cluster in Cantonese, and outperform their L2
counterparts on the licit Mandarin cluster [le ne] that has a Cantonese equivalent. This is regarded as strong evidence of
transfer effects from Cantonese, which is typologically and structurally more similar to Mandarin than English. We hence argue that L3
initial transfer is not determined by the order of the languages previously acquired but the structural similarity. More importantly, our
study shows that transfer effects can be facilitative as well as detrimental. In addition, our data cross different proficiency levels show
that factors such as the learning situation (learning or unlearning), word frequency and form-meaning relationship can influence the success
of acquisition of a specific property in the L3.
Acoustic analysis of Chinese tone production by Thai-speaking learners of L2 Chinese
Authors: Zhang Ling , Liu Shi
Published: November 2020

This article reports on an empirical study of Chinese tone production in various contexts by Thai-speaking learners of L2
Chinese. Comparisons are made between Thai students and Chinese native speakers. The acoustic data are analyzed in terms of pitch register,
pitch contour and duration, which show that the main problems of Thai students are: (1) T1 is lower in sentence-mid and sentence-initial
positions; (2) T2 is less rising or even exhibits a falling-rising contour at a lower register; (3) T3 cannot approximate a full
falling-rising contour in isolated characters and at sentence-final position; (4) T4 is too long and the falling slope is too strong. Our results suggest that Thai students should make efforts in both pitch and rhythm control and pay attention to context
variations. It is also suggested that similar research methods can be applied to L2 Chinese learners with different first languages
(L1s).
Shear-Banding Evolution Dynamics during High Temperature Compression of Martensitic Ti-6Al-4V Alloy*
Authors: Zhang Xue-Hua , Li Rong , Zhao Yong-Qing , Zeng Wei-Dong
Published: November 2020

The isothermal compression dynamics of ternary Ti-6Al-4V alloy with initial martensitic structures were investigated in the high temperature range 1083–1173 K and moderate strain rate regime 0.01–10 s−1. Shear banding was found to still dominate the deformation mechanism of this process, despite its nonadiabatic feature. The constitutive equation was derived with the aid of Zener–Hollomon parameter, which predicted the apparent activation energy as 534.39 kJ/mol. A combination of higher deformation temperature and lower strain rate suppressed the peak flow stress and promoted the evolution of shear bands. Both experiments and calculations demonstrated that a conspicuous temperature rise up to 83K could be induced by severe plastic deformation. This facilitated the dynamic recrystallization of deformed martensites, as evidenced by the measured microhardness profiles across shear bands.
Comment on ‘Improving series convergence: the simple pendulum and beyond’
Authors: Fernández Francisco M
Published: November 2020

In this comment we analyze the improved series proposed by Duki et al (2018 Eur. J. Phys.
39 065802) for the approximate calculation of a variety of physical quantities like the period of the simple pendulum and an integral of the exponential of a two-dimensional potential-energy function. We show that the application of the approach to the latter case is unnecessary because both the expansion coefficients and the original problem are given in terms of a similar error function. Present results for the straightforward expansion with exact analytic coefficients do not show the oscillatory behaviour exhibited by the calculations of those authors. We give reasons why the improved approach of Duki et al may not be suitable for the treatment of many realistic physical problems.
Ways of incorporating active learning experiences: an exploration of worksheets over five years in a first year Thai physics courses
Authors: Eambaipreuk A , Arayathanitkul K , Emarat N , Sharma M D
Published: November 2020

It has been established that the incorporation of active learning experiences in the context of university lectures increases overall student learning. This study contributes to the literature by examining iterations of incorporating interactivity where the ‘intensity’, in terms of the content, structure and time spent on different in-class activities is varied. The study described in this paper deals in some depth with the use of worksheets during lectures on the topic of circular motion. The study was done with a total of 1405 students studying first-year physics over five years at Mahidol University, Thailand. Over these years, the style of the worksheets as well as the in-class activities were modified. In the first year, the worksheet contained a subsection for note taking as well as problem-solving practice; in the second year, a problem-solving strategy was introduced; in the third year, a lecture demonstration with associated free-body diagrams was included; in the final two years, these diagrams were modified. There was a statistically significant difference between student performance on an examination question of circular motion between the first-year cohort and the cohorts of later years. However, the results for later years indicate a saturation of mean scores. This saturation level needs to be further investigated under different topics, with different cohorts and with different types of active learning.
Novel narrowband radio frequency microelectromechanical systems filters
Authors: Liu Wenli , Chen Zeji , Kan Xiao , Wang Tianyun , Jia Qianqian , Zhu Yinfang , Zhao Jicong , Yuan Quan , Yang Jinling , Yang Fuhua
Published: November 2020

This work presents three new narrowband radio frequency
(RF) microelectromechanical systems (MEMS) filters made from mechanical or electrically coupled resonators with a quality factor Q of over 10 000. A low-stiffness rectangular-frame mechanical coupling beam (RFCB) is designed, and a filter with an RFCB is successfully developed with a center frequency of 75.5 MHz and a percent bandwidth (BW) of 0.4%. In addition, a tunable narrowband filter is achieved with a mechanically coupled four-disk linear structure filter. The center frequencies are 74.47 ± 0.54 MHz and the percent BW range is 0.48%–2.2%. In order to further simplify the architecture of the filter, a filter based on a single whisper gallery mode disk resonator is demonstrated, which has a center frequency of 79.42 MHz and a BW of only 0.25%. The three different RF MEMS filters have potential applications in wireless communication systems.
The realization of quantum anomalous Hall effect in two dimensional electron gas
Authors: Wu Hua-rui , Wu Bing-lan , Cheng Shu-guang , Jiang Hua
Published: November 2020

The quantum anomalous Hall effect (QAHE), carrying dissipationless chiral edge states, occurs without any magnetic field. Two main strategies were proposed to host QAHE: the magnetic topological insulator thin films and graphene systems. Only the former one was realized in experiment at low temperature. In this paper, by dealing with the two-dimensional electron gas with an anti-dot lattice, a realistic platform is proposed to host the QAHE with both Chern number

C
=
−
1

and

C
=
2

. Based on the calculation of the Berry curvature integral and spacial wave function, the topological nature of the QAH edge states is well demonstrated. In the QAH region, the conductance shows quantized plateaus and their values are robust against Anderson disorder. In addition, we have also studied the effects of the size and shape of the anti-dot lattice on QAHE and they provide extra manners to adjust the system parameters. Taking the advantages of the well developed micro-manufacture technique in semiconductors, the proposal is experimentally accessible in micro-scale.
Effect of zitterbewegung on the propagation of wave packets in ABC-stacked multilayer graphene: an analytical and computational approach
Authors: Lavor I R , da Costa D R , Chaves Andrey , Sena S H R , Farias G A , Van Duppen B , Peeters F M
Published: November 2020

The time evolution of a low-energy two-dimensional Gaussian wave packet in ABC-stacked n-layer graphene (ABC-NLG) is investigated. Expectation values of the position (x, y) of center-of-mass and the total probability densities of the wave packet are calculated analytically using the Green’s function method. These results are confirmed using an alternative numerical method based on the split-operator technique within the Dirac approach for ABC-NLG, which additionally allows to include external fields and potentials. The main features of the zitterbewegung (trembling motion) of wave packets in graphene are demonstrated and are found to depend not only on the wave packet width and initial pseudospin polarization, but also on the number of layers. Moreover, the analytical and numerical methods proposed here allow to investigate wave packet dynamics in graphene systems with an arbitrary number of layers and arbitrary potential landscapes.
Robust cepstral analysis at variable wavelength scan depth for narrowband tunable laser absorption spectroscopy
Authors: Li Jidong , Schwarm Kevin K , Wei Chuyu , Mitchell Spearrin R
Published: November 2020

This work focuses on optimizing the modified free induction decay (m-FID) method, or cepstral analysis, for accuracy, precision, and robustness in performing laser absorption spectroscopy at conditions of variable baseline distortion where laser tuning range is of a similar order of magnitude as the targeted spectral linewidth. The optimum selections of the initial and final time of the m-FID signal were assessed at variable scan indices (ratio of laser scan range to spectral linewidth), and guidance is offered in parameter selection based on scan index and noise characteristics of the optical system. The sensitivities of the m-FID method to multiple types of baseline distortion were also analyzed to reflect typical experimental factors such as beam attenuation, background radiation, and laser stability. Experimental demonstration of the technique was performed with an interband cascade laser targeting the CO2 transition (0001

←

0000) R(60) near 4.2 micron to measure gas concentration at variable scan indices in a static cell by using both the m-FID and direct absorption spectroscopy (DAS) method while varying injection current amplitude. An estimated baseline was determined by the measured laser output and superimposed with different types and levels of distortion. Under conditions of signal distortion, the m-FID method is shown to demonstrate superior accuracy and precision with smaller deviations in time than that rendered by typical DAS, especially at smaller scan depths, showing its potential for measurements at elevated pressures or at a high scan frequency where distributed feedback lasers typically yield narrower tuning range.
Fixing positions and orientations of laser trackers during bundle adjustment in multi-station measurements
Authors: Wang Zhaoyi , Luo Tao , Wang Wei , Huang Qingqing , Li Xiao
Published: November 2020

The accumulated errors in multi-station measurements make it challenging to meet higher precision requirements for annular or straight tunnel measurements in the accelerator alignment field. In this paper, a study on fixing positions and orientations of laser trackers during the bundle adjustment is presented. First, we adopt the mixed least squares-total least squares algorithm to calculate the spatial-transformation parameters. Then, according to the principle of bundle adjustment based on laser trackers, we design four schemes and compare them to determine which scheme results in the highest precision. Experimental results show that fixing each station’s position and orientation can considerably decrease the absolute point errors from 0.130 to 0.069 mm within 15 m × 10 m × 3 m, and fixing stations’ orientations is better than fixing their positions. This research can derive high-precision schemes that effectively reduce accumulated errors in annular or straight tunnel measurements, and it can apply to other robotic sensors as well.
The effects of substitutional Fe-doping on magnetism in MoS2 and WS2 monolayers
Authors: Kang Kyungnam , Fu Shichen , Shayan Kamran , Anthony Yoshimura , Dadras Siamak , Yuzan Xiong , Kazunori Fujisawa , Terrones Mauricio , Zhang Wei , Strauf Stefan , Meunier Vincent , Vamivakas A Nick , Yang Eui-Hyeok
Published: November 2020

Doping of two-dimensional (2D) semiconductors has been intensively studied toward modulating their electrical, optical, and magnetic properties. While ferromagnetic 2D semiconductors hold promise for future spintronics and valleytronics, the origin of ferromagnetism in 2D materials remains unclear. Here, we show that substitutional Fe-doping of MoS2 and WS2 monolayers induce different magnetic properties. The Fe-doped monolayers are directly synthesized via chemical vapor deposition. In both cases, Fe substitutional doping is successfully achieved, as confirmed using scanning transmission electron microscopy. While both Fe:MoS2 and Fe:WS2 show PL quenching and n-type doping, Fe dopants in WS2 monolayers are found to assume deep-level trap states, in contrast to the case of Fe:MoS2, where the states are found to be shallow. Using μm- and mm-precision local NV− magnetometry and superconducting quantum interference device, we discover that, unlike MoS2 monolayers, WS2 monolayers do not show a magnetic phase transition to ferromagnetism upon Fe-doping. The absence of ferromagnetism in Fe:WS2 is corroborated using density functional theory calculations.
Gold nanoparticle-assisted plasmonic enhancement for DNA detection on a graphene-based portable surface plasmon resonance sensor
Authors: Prabowo Briliant Adhi , Purwidyantri Agnes , Liu Bei , Lai Hsin-Chih , Liu Kou-Chen
Published: November 2020

The impact of different gold nanoparticle (GNP) structures on plasmonic enhancement for DNA detection is investigated on a few-layer graphene (FLG) surface plasmon resonance (SPR) sensor. Two distinct structures of gold nano-urchins (GNu) and gold nanorods (GNr) were used to bind the uniquely designed single-stranded probe DNA (ssDNA) of Mycobacterium tuberculosis complex DNA. The two types of GNP-ssDNA mixture were adsorbed onto the FLG-coated SPR sensor through the π-π stacking force between the ssDNA and the graphene layer. In the presence of complementary single-stranded DNA, the hybridization process took place and gradually removed the probes from the graphene surface. From SPR sensor preparation, the annealing process of the Au layer of the SPR sensor effectively enhanced the FLG coverage leading to a higher load of the probe DNA onto the sensing interface. The FLG was shown to be effective in providing a larger surface area for biomolecular capture due to its roughness. Carried out in the DNA hybridization study with the SPR sensor, GNu, with its rough and spiky structures, significantly reinforced the overall DNA hybridization signal compared with GNr with smooth superficies, especially in capturing the probe DNA. The DNA hybridization detection assisted by GNu reached the femtomolar range limit of detection. An optical simulation validated the extreme plasmonic field enhancement at the tip of the GNu spicules. The overall integrated approach of the graphene-based SPR sensor and GNu-assisted DNA detection provided the proof-of-concept for the possibility of tuberculosis disease screening using a low-cost and portable system to be potentially applied in remote or third-world countries.
Nanoconstructs as a versatile tool for detection and diagnosis of Alzheimer biomarkers
Authors: Gopalan Divya , Pandey Abhijeet , Alex Angel Treasa , Kalthur Guruprasad , Pandey Sureshwar , Udupa Nayanabhirama , Mutalik Srinivas
Published: November 2020

The current review focuses towards the advancements made in the past decade in the field of nanotechnology for the early Alzheimer’s disease (AD) diagnosis. This review includes the application of nanomaterials and nanosensors for the early detection of the main AD biomarkers (amyloid beta, phosphorylated tau, apolipoprotein E4 allele or APOE4, microRNAs, cholesterol, hydrogen peroxide etc) in biological fluids, to detect the biomarkers at a very low concentration ranging in pico, femto and even atto molar concentrations. The field of drug development has always aimed and is constantly working on developing disease modifying drugs, but these drugs will only succeed when given in the early disease stages. Thus, developing efficient diagnostic tools is of vital importance. Various nanomaterials such as liposomes; dendrimers; polymeric nanoparticles; coordination polymers; inorganic nanoparticles such as silica, manganese oxide, zinc oxide, iron oxide, super paramagnetic iron oxides; quantum dots, silver nanoparticles, gold nanoparticles, and carbon based nanostructures (carbon nanotubes, graphene oxide, nanofibres, nanodiamonds, carbon dots); Up-conversion nanoparticles; 2D nanomaterials; and radioactive nanoprobes have been used in constructing and improving efficiency of nano-sensors for AD biosensing at an early stage of diagnosis.
Balls rolling down a playground slide: What factors influence their motion?
Authors: Pendrill Ann-Marie
Published: November 2020

Take a selection of balls and marbles along to a nearby playground slide and let students investigate factors that may influence how balls accelerate down an inclined plane. Students can make hypotheses in small groups, plan investigations to test multiple possible explanations and draw conclusions about the importance of different variables. The experiments illustrate the principle of equivalence between inertial and gravitational mass, as well as of the importance of mass distribution. Students can develop an intuitive feeling for these concepts even without dealing with the full mathematical treatment, which involves torque, angular momentum and moment of inertia, typically treated in high-school or introductory university physics courses. The paper discusses this investigation as part of a setup of teacher professional development events on a playground.
Liver-ultrasound-guided lung tumour tracking for scanned proton therapy: a feasibility study
Authors: Krieger Miriam , Giger Alina , Jud Christoph , Duetschler Alisha , Salomir Rares , Bieri Oliver , Bauman Grzegorz , Nguyen Damien , Cattin Philippe C , Weber Damien C , Lomax Antony J , Zhang Ye
Published: November 2020

Pencil beam scanned (PBS) proton therapy of lung tumours is hampered by respiratory motion and the motion-induced density changes along the beam path. In this simulation study, we aim to investigate the effectiveness of proton beam tracking for lung tumours both under ideal conditions and in conjunction with a respiratory motion model guided by real-time ultrasound imaging of the liver. Multiple-breathing-cycle 4DMRIs of the thorax and abdominal 2D ultrasound images were acquired simultaneously for five volunteers. Deformation vector fields extracted from the 4DMRI, referred to as ground truth motion, were used to generate 4DCT(MRI) data sets of two lung cancer patients, resulting in 10 data sets with variable motion patterns. Given the 4DCT(MRI) and the corresponding ultrasound images as surrogate data, a patient-specific motion model was built. The model consists of an autoregressive model and Gaussian process regression for the temporal and spatial prediction, respectively. Two-field PBS plans were optimised on the reference CTs, and 4D dose calculations (4DDC) were used to simulate dose delivery for (a) unmitigated motion, (b) ideal 2D and 3D tracking (both beam adaption and 4DDC based on ground truth motion), and (c) realistic 2D and 3D tracking (beam adaption based on motion predictions, 4DDC on ground truth motion). Model-guided tracking retrieved clinically acceptable target dose homogeneity, as seen in a substantial reduction of the D5%–D95% compared to the non-mitigated simulation. Tracking in 2D and 3D resulted in a similar improvement of the dose homogeneity, as did ideal and realistic tracking simulations. In some cases, however, the tracked deliveries resulted in a shift towards higher or lower dose levels, leading to unacceptable target over- or under-coverage. The presented motion modelling framework was shown to be an accurate motion prediction tool for the use in proton beam tracking. Tracking alone, however, may not always effectively mitigate motion effects, making it necessary to combine it with other techniques such as rescanning.
Towards effective assessment of normal hearing function from ABR using a time-variant sweep-tone stimulus approach
Authors: Jiang Yanbing , Samuel Oluwarotimi Williams , Zhang Haoshi , Chen Shixiong , Li Guanglin
Published: November 2020

Objective. The auditory brainstem response (ABR) audiometry is a means of assessing the functional status of the auditory neural pathway in the clinic. The conventional click ABR test lacks good neural synchrony and it mainly evaluates high-frequency hearing while the common tone-burst ABR test only detects hearing loss of a certain frequency at a time. Additionally, the existing chirp stimuli are designed based on average data of cochlear characteristics, ignoring individual differences amongst subjects. Approach. Therefore, this study designed a new stimulus approach based on a sweep-tone concept with a time variant and spectrum characteristics that could be customized based on an individual’s cochlear characteristics. To validate the efficiency of the proposed method, we compared its performance with the click and tone-bursts using ABR recordings from 11 normal-hearing adults. Main results. Experimental results showed that the proposed sweep-tone ABR achieved a higher amplitude compared with those elicited by the click and tone-bursts. When the stimulus level or rate was varied, the sweep-tone ABR consistently elicited a larger response than the corresponding click ABR. Moreover, the sweep-tone ABR appeared earlier than the click ABR under the same conditions. Specifically, the mean wave V peak-to-peak amplitude of the sweep-tone ABR was 1.3 times that of the click ABR at 70 dB nHL (normal hearing level) and a rate of 20 s−1, in which the former saved 40% of test time. Significance. In summary, the proposed sweep-tone approach is found to be more efficient than the traditional click and tone-burst in eliciting ABR.
Machining method for controlling the behaviours of Bingham fluids in cluster magnetorheological polishing pads
Authors: Luo Bin , Yan Qiusheng , Huang Zhanliang , Pan Jisheng , Fu Youzhi
Published: November 2020

Cluster magnetorheological finishing is a novel machining method for attaining super-smooth and even surfaces. The aim of the research is to strengthen the role of cluster magnetorheological polishing pads and improve the material removal rate (MRR) while attaining smooth and undamaged surfaces. To this end, a novel polishing disk with three-dimensional (3D) microstructures was formed by machining an array of holes on the surface of a polishing disk. The influences of the type of abrasives, geometric parameters of the holes, and polishing time on the roughness and MRR of the machined surface were explored. The test result showed that a polishing disk with multiple holes contributes to a higher MRR and a lower surface roughness relative to a smooth polishing disk, significantly improving the polishing effect; the diameter and distribution of multiple holes on the surface of the polishing disk exhibit a significant effect on the polishing process. The polishing effect with silica sols is most remarkably improved. The solid-state chemical reaction between sapphire and silica sols promotes material removal; relative to a smooth polishing disk, the MRR is increased by 107% and the surface roughness is decreased by 11%. The surface roughness is reduced from Ra 5.14 nm to Ra 0.24 nm by utilising the optimised technological parameters. Under the synergistic action of mechanical removal enhancement of polishing disks with multiple holes and chemical removal of silica sol sapphire can obtain super smooth undamaged surfaces efficiently.
Quantum hydrodynamics description of spin-1 Bose–Einstein condensates
Authors: Trukhanova Mariya Iv , Obukhov Yuri N
Published: November 2020

We develop a novel model of the magnetized spin-1 Bose–Einstein condensate (BEC) of neutral atoms, using the method of many-particle quantum hydrodynamic (QHD) and propose an original derivation of the system of continual equations. We consider bosons with a spin-spin interaction and a short range interaction in the first order in the interaction radius, on the of basis of the self-consistent field approximation of the QHD equations. We demonstrate that the dynamics of the fluid velocity and magnetization is determined by a nontrivial modification of the Euler and Landau–Lifshitz equation, and show that a nontrivial modification of the spin density evolution equation contains the spin torque effect that arises from the self-interactions between spins of the bosons. The properties of the dispersion spectrum of collective excitations are described. We obtain the new contribution of the self-interaction of spins in the spin wave spectrum together with the influence of an external magnetic field and spin-spin interactions between polarized particles. The anisotropic spin wave instability is predicted.