bluuebunny/crossref_metadata_2025 huggingface dataset:
Research on assimilation simulation of chlorophyll a concentrations in a virtual geographic environment
Authors: Guo Fei , Yang Jing , Zhang Jingjia , Zhang Zhuo , Xu Xin , Zhang Hong
Published: July 2021

Chlorophyll a concentration is an important parameter for the characterization of water quality and reflects the degree of eutrophication and the algae content in water bodies. Based on the idea of integrating models, data and visualization to build virtual geographic environments (VGEs), this article proposes a data assimilation scheme based on particle filters to assimilate the concentration of chlorophyll a in a VGE. The VGE is based on a modular concept to design function plugins and perform water quality assimilation simulations and GIS visualization. We conducted assimilation experiments using buoy observation data and forecast chlorophyll a concentrations. During the assimilation stage, the root mean square error and average relative error are notably reduced. The assimilation results indicate that the proposed data assimilation method can significantly improve accuracy in the prediction of chlorophyll a concentrations. An assimilation case study indicates that the VGE can be effectively used in water environment pollution and dynamic process simulations.
Las desesperantes horas de ocio: tiempo y diversión en Bogotá (1849-1900)
Authors: Ruiz Patiño Jorge Humberto
Published: July 2021

Al finalizar el siglo XIX, la clase alta de Bogotá se divertía con conciertos de ópera, corridas de toros en la forma moderna, carreras de caballos al estilo inglés y carreras de bicicletas. Si bien los teatros, el hipódromo y el circo de toros fueron los lugares de recreo predilectos de ese grupo social, al igual que los parques y jardines, esto no siempre fue así. Durante los primeros años de la república y parte de la segunda mitad del siglo XIX, los bogotanos gozaban con las diversiones heredadas de la Colonia: corridas de toros en la forma tradicional, riñas de gallos y juegos de azar. En Las desesperantes horas de ocio, Jorge Humberto Ruiz estudia cómo el cambio histórico en el orden de las diversiones en Bogotá estuvo relacionado, principalmente, con las representaciones de las diversiones de origen colonial dentro de la disputa partidista, la formación de un ámbito de los espectáculos públicos, la transformación de las plazas coloniales en parques y jardines, y la representación del tiempo como un bien escaso, que debía ser usado en beneficio de la perfectibilidad humana. De este modo, este libro profundiza y expande los estudios sociales sobre la fiesta, las diversiones y el ocio en Colombia al demostrar que su historia es también una historia de cómo se conciben el tiempo, el trabajo y aquello que los seres humanos son y crean cuando pueden estar juntos en su tiempo lúdico.
Assessment of Geometric Nonlinearities Influence On NASA Rotor 37 Response to Blade Tip/Casing Rubbing Events
Authors: Delhez Elise , Nyssen Florence , Golinval Jean-Claude , Batailly Alain
Published: July 2021

This paper uses a recently derived reduction procedure to study the contact interactions of an industrial blade undergoing large displacements. The reduction technique consists in projecting the dynamical problem onto a reduction basis composed of Craig-Bampton modes and a selection of their modal derivatives. The internal nonlinear forces due to large displacements are evaluated with the stiffness evaluation procedure and contact is numerically handled using Lagrange multipliers. The numerical strategy is applied on an open industrial compressor blade model based on the NASA rotor 37 blade in order to promote reproducibility of results. Two contact scenarios are investigated: one with direct contact between the blade and the casing and one with an abradable material deposited on the casing. The influence of geometric nonlinearities is assessed in both cases. In particular, contact interaction maps and abradable coating wear pattern maps are used to identify the main interactions that can be detrimental for the engine integrity.
Three-dimensional numerical analysis as a tool for optimization of acoustophoretic separation in polymeric chips
Authors: de los Reyes Elena , Acosta Victor , Carreras Pilar , Pinto Alberto , González Itziar
Published: July 2021

Polymeric separators have been developed since 2010 to produce acoustophoretic separation of particles or cells in suspension with high efficiency. They rely on three-dimensional (3D) resonances of their whole structure actuated by ultrasounds. In this paper, a numerical 3D analysis is presented and validated as the only tool for optimization of these polymeric chips to perform efficient separation applications. In contrast to conventional acoustophoretic techniques based on the establishment of standing waves in the liquid phase of the channel (requiring rigid chip materials, such as silicon or glass), whole-structure resonances of the chip allow the use of materials that are acoustically soft and of low acoustic impedance, which is close to that of the liquid samples hosted. The resonance requirement is not restricted to the liquid phase in the polymeric chips, but it extends to the 3D whole structure, allowing any material. It provides significant advantages in the design and manufacture of our chips, allowing the use of low-cost materials and cheap manufacturing processes and even printing of devices. The extraordinary complexity of their multiple resonances requires theoretical approaches to optimize their acoustophoretic performance. Hence, the importance of 3D numerical analyses, which are capable of predicting the acoustic behavior of these chips, is to perform acoustophretica separation in suspensions.
Distinguishing volcanic from impact glasses—The case of the Cali glass (Colombia)
Authors: Ferrière Ludovic , Crósta Alvaro P. , Wegner Wencke , Libowitzky Eugen , Iwashita Fabio , Koeberl Christian
Published: July 2021

Natural glass occurs on Earth in different geological contexts, mainly as volcanic glass, fulgurites, and impact glass. All these different types of glasses are predominantly composed of silica with variable amounts of impurities, especially the alkalis, and differ in their water content due to their mode of formation. Distinguishing between different types of glasses, on Earth and also on the Moon and on other planetary bodies, can be challenging. This is particularly true for glasses of impact and volcanic origin. Because glass is often used for the determination of the age of geological events, even if out of geological context, as well as to derive pressure and temperature constraints, or to evaluate the volatile contents of magmas and their source regions, we rely on methods that can unambiguously distinguish between the different types of glasses. We used the case of the Cali glass, found in an extended area close to the city of Cali in western Colombia, which was previously suggested to be of impact or volcanic origin, to show that, using a multimethod approach (i.e., combining macroscopic observations, chemical and isotopic data, and H2O content), it is possible to distinguish between different formation modes. A suite of Cali glass samples was analyzed using electron microprobe, instrumental neutron activation analysis, thermal ionization mass spectrometry, and Fourier-transform infrared spectroscopy, allowing us to definitively exclude an impact origin and instead classify these glasses as a rhyolitic volcanic glass (obsidian). Our results suggest that other “unusual glass occurrences” that are claimed, but not convincingly proven, to be of impact origin should be reexamined using the same methodology as that applied here.
3 Epidemiology of running-related injuries in the Korean population: a cross-sectional survey of 1046 runners
Authors: Rhim HC , Kim SJ , Jeon JS , Nam HW , Jang KM
Published: July 2021

Aims

Running is the oldest form of exercise in human history and the most popular exercise in the world.1While running can improve physical fitness and reduce chronic health problems such as obesity and cardiovascular disease, it is also associated with injuries in lower extremities.2However, because there was no consensus definition of running-related injury, the prevalence and incidence of running-related injuries had been reported to vary between 19% and 92%.3Moreover, epidemiology of running-related injuries in Asian populations has been rarely investigated. Therefore, this study was first to use the consensus definition of running-related injuries published in 20153and investigated the epidemiology of running-related injuries in the Korean population.

Methods

In cross-sectional design, an online survey was circulated among various running communities in Korea. The questionnaire contained information on presence and location of pain attributed to running, demographic characteristics, weekly running mileage, training intensity, running pace, type of shoes, foot strike, reason for running, and exercise experience prior to running.

Results

Among 1046 runners (male=624, female 422) who responded, 94.7% experienced some kind of pain while running, but only 37% were categorized to have running-related injuries. The most common site of injury was the knee followed by ankle. Exercise experience prior to running (OR 1.57 95% CI 1.13–2.21), setting of specific running goals (OR 1.57 95% CI 1.08–2.27), and mileage increases from 20–30 km to 30–40 km (OR 1.66 95% CI 1.06–2.63) were associated with significant increases in running-related injuries.

Conclusion

In order to avoid running-related injuries, runners should be careful in increasing weekly mileage. Moreover, runners with previous exercise experience may need to approach running more cautiously. Setting goals may be motivating but at the same time can increase the risk of running-related injuries.

References

Videbæk S, Bueno AM, Nielsen RO, Rasmussen S. Incidence of running-related injuries per 1000 h of running in different types of runners: a systematic review and meta-analysis.Sports medicine2015;45(7):1017–26.

Van Gent R, Siem D, van Middelkoop M, Van Os A, Bierma-Zeinstra S, Koes B. Incidence and determinants of lower extremity running injuries in long distance runners: a systematic review.British Journal of Sports Medicine2007;41(8):469–80.

Yamato TP, Saragiotto BT, Lopes AD. A consensus definition of running-related injury in recreational runners: a modified Delphi approach.Journal of orthopaedic & sports physical therapy2015;45(5):375–80.
5 Examination of the relationship between changes in workload and changes in loaded countermovement jump during a rugby union season
Authors: Strong Rob , West Daniel , Kupsarevic Joe
Published: July 2021

Background

The loaded countermovement jump (CMJ) is a variation on the normal CMJ (bodyweight-only), used routinely in sport settings as a measure of neuromuscular fatigue (NMF). Although commonplace, the CMJ variables that are most sensitive to NMF remain somewhat unclear.

Purpose

The aim of this study was to examine the relationship between changes in workload and changes in the loaded CMJ; specifically, to determine its suitability for assessment of NMF.

Methods

Eighteen professional rugby union players performed loaded CMJ tests on seven occasions over the course of thirteen weeks, during an English top-flight season. Eight CMJ variables were measured, assessing different aspects of the CMJ. Workload was measured by GPS total distance and was the sum of the previous week’s data, recorded in on-field training and match-play. Spearman’s rank-order correlations were calculated to identify the relationship between changes in workload and changes in loaded CMJ variables.

Results

No significant relationships were found between loaded CMJ variables and workload with no lag or workload lagged one week. Significant relationships were found between workload lagged 2 weeks and flight time/contact time (FT-CT;rs=-0.35; p=0.04) and time to peak power (TtPP;rs=0.35;p=0.05).

Conclusion

This study suggests loaded CMJ is not a suitable test to monitor acute changes to NMF. However, results also indicate that FT-CT and TtPP, are associated with changes in workload lagged 2-weeks. Therefore, certain CMJ variables may prove useful to help prescribe alterations to athlete training plans following periods of heavy workload.
Clinical utility of peptide microarrays in the serodiagnosis of neglected tropical diseases in sub-Saharan Africa: protocol for a diagnostic test accuracy systematic review
Authors: Vengesai Arthur , Naicker Thajasvarie , Kasambala Maritha , Midzi Herald , Mduluza-Jokonya Tariro , Rusakaniko Simbarashe , Mduluza Takafira
Published: July 2021

Introduction

Neglected tropical diseases tend to cluster in the same poor populations and, to make progress with their control, they will have to be dealt with in an integrated manner. Peptide microarrays may be a solution to these problems, where diagnosis for co-infection can be detected simultaneously using the one tool. A meta-analysis using hierarchical models will be performed to assess the diagnostic accuracy of peptide microarrays for detecting schistosomiasis (Schistosoma mansoniandS. haematobium), soil-transmitted helminths (Trichuris trichiura,Ascaris lumbricoidesandNecator americanus), trachoma (Chlamydia trachomatis), lymphatic filariasis (Wuchereria bancrofti) and onchocerciasis (Onchocerca volvulus) in people residing in sub-Saharan Africa.

Methods and analysis

A comprehensive search of the following databases will be performed: Cochrane Infectious Diseases Group Specialised Register, PubMed, EMBASE and The Web of Science. Studies comparing peptide microarrays with a reference standard from a random or consecutive series of patients will be included in the study. Two review authors will independently screen titles and abstracts for relevance, assess full-text articles for inclusion and carry out data extraction using a tailored data extraction form. The quality Assessment of Diagnostic Accuracy Studies-2 tool will be used to assess the quality of the selected studies. The bivariate model and the hierarchical summary receiver operating characteristic curve model will be performed to evaluate the diagnostic accuracy of the peptide microarrays. Meta-regression analyses will be performed to investigate heterogeneity across studies.

Ethics and dissemination

There is no requirement for ethical approval because the work will be carried out using previously published data, without human beings involvement. Findings will be disseminated through peer-reviewed publication and in conference presentations.

PROSPERO registration number

CRD42020175145.
Influence of ecological momentary assessment study design features on reported willingness to participate and perceptions of potential research studies: an experimental study
Authors: Smyth Joshua M , Jones Dusti R , Wen Cheng K F , Materia Frank T , Schneider Stefan , Stone Arthur
Published: July 2021

Objective

Intensive ambulatory assessment, such as ecological momentary assessment (EMA), is increasingly used to capture naturalistic patient-reported outcomes. EMA design features (eg, study duration, prompt frequency) vary widely between studies, but it is not known if such design decisions influence potential subjects’ willingness to participate in a study. We hypothesise that intentions to participate will be higher in studies that are less burdensome and have higher reward (eg, compensation).

Design

This experimental study examined if four EMA study design features (study duration, prompt frequency, prompt length, compensation) affected intentions to participate in a hypothetical EMA study and participation appraisals (eg, participation effort). Participants were randomly assigned to conditions (reflecting a fully crossed design of the four features, each with two levels). Each condition presented a vignette describing a study (each a unique combination of design features) and asked them to report on likelihood of participating and study appraisals.

Participants

A convenience sample of participants (n=600; 46% female,Mage=40.39) were recruited using an online service.

Primary and secondary outcome measures

Primary outcomes were willingness to participate (No/Yes) and reported participation likelihood (0–100 scale). Secondary outcomes included appraisals of interest, enjoyment, effort, and if the study makes a valuable contribution to science.

Results

We examined main effects, and two-way interactions for participation likelihood, across study design features. Overall, reported willingness to participate and participation likelihood were high (89%,M=83.90, respectively). Shorter study duration, fewer prompts, shorter prompts and higher compensation increased willingness to participate and elicited higher participation likelihood (each associated with ~6%–8% increases). Findings suggested that more intensive studies were judged as somewhat less interesting and enjoyable, and requiring more effort.

Conclusion

Hypotheses were generally supported. Design features influence behavioural intentions to participate in, and appraisals of, EMA studies. Implications for participant recruitment and generalisability, and remaining research questions, are discussed.
Two-year follow-up cohort study focused on gender-specific associations between socioeconomic status and body weight changes in overweight and obese middle-aged and older adults
Authors: Biskup Malgorzata , Macek Pawel , Gozdz Stanislaw , Terek-Derszniak Malgorzata , Krol Halina , Kedzierawski Piotr , Zak Marek
Published: July 2021

Objective

As overall spread of obesity in populations is generally acknowledged to result from unhealthy lifestyles rather than individual genetic makeup, this study aimed to gain specific insights into its determinants through assessing the prevalent associations between individual socioeconomic status (SES) and weight loss in overweight and obese men and women.

Methods

A prospective, 2-year follow-up study covered 3362 (38.0% men) respondents, aged 43–64 years, body mass index ≥25 kg/m2. Changes in body weight were estimated as a percentage of initial weight. Three categories of changes were defined: gained ≥3%, stable (gained <3% or lost <3%), lost ≥3%. Body weight loss was determined against three categories: lost ≥3 to <5%, lost ≥5 to <10%, lost ≥10%. Select SES variables (ie, gender, age, education, marital status, occupational activity and income) were determined in line with the Health Status Questionnaire. The associations between SES and body weight changes were analysed with the aid of logistic regression models. The results were presented as ORs with 95% CIs.

Results

Only 18% of the respondents had complied with the medical recommendations on weight loss. Significant differences were encountered between the gender, age and occupational activity variables and the weight loss one. Multifactorial models were used to determine the following gender-specific associations between SES and weight loss. Men with moderate income had significantly higher odds for weight loss (≈75%), as compared with the higher earners, whereas women with low income, occupationally inactive, had significantly higher odds (≈30% and ≈50%, respectively), as compared with the high earners and occupationally active ones.

Conclusions

Lower education, male gender, lower income per household, older age and unemployment status were the established factors predisposing to obesity. While aiming to ensure effectiveness of the measures specifically aimed at preventing obesity, population groups deemed most at risk of potential weight gain must prior be identified.
Role of hypertension in the association of overweight and obesity with diabetes among adults in Bangladesh: a population-based, cross-sectional nationally representative survey
Authors: Hossain Md Belal , Khan Jahidur Rahman , Das Gupta Rajat
Published: July 2021

Aims

Overweight and obesity (OWOB) is a modifiable risk factor for both hypertension and diabetes. However, the association between OWOB and diabetes among Bangladeshi adults and how hypertension may mediate this relationship are not well explored. This study aimed to examine (1) whether OWOB is independently associated with diabetes among Bangladeshi adults, (2) whether this association is mediated by hypertension, and (3) the effect modification by wealth status and place of residence in the relationships.

Research design and methods

We used data of 9305 adults aged ≥18 years from the most recent nationally representative cross-sectional study of Bangladesh Demographic and Health Survey 2017–2018. Design-based logistic regression was used to assess the association between OWOB and diabetes, and counterfactual framework-based weighting approach was used to evaluate the mediation effect of hypertension in the OWOB–diabetes relationship. We used stratified analyses for the effect modifications.

Results

The prevalence of OWOB, diabetes and hypertension was 48.5%, 11.7% and 30.3%, respectively. We observed a significant association between OWOB and diabetes and a mediating role of hypertension in the OWOB–diabetes association. The odds of diabetes was 51% higher among adults with OWOB than those without OWOB (adjusted OR: 1.51, 95% CI 1.29 to 1.77). We observed that 18.64% (95% CI 9.84% to 34.07%) of the total effect of OWOB on the higher odds of diabetes was mediated through hypertension, and the mediation effect was higher among adults from non-poor households and from both rural and urban areas.

Conclusions

Adult OWOB status is independently associated with diabetes in Bangladesh, and hypertension mediates this association. Therefore, prevention policies should target adults with both OWOB and hypertension, particularly those from non-poor households and from both rural and urban areas, to reduce the growing burden of diabetes and its associated risk.
Asymptomatic COVID-19 infection: diagnosis, transmission, population characteristics
Authors: You Yaxian , Yang Xinyuan , Hung Dongni , Yang Qianxi , Wu Ting , Deng Meichun
Published: July 2021

A novel coronavirus first discovered in late December 2019 has spread to many countries around the world. An increasing number of asymptomatic patients have been reported and their ability to spread the virus has been proven. This brings major challenges to the control of the transmission. The discovery and control of asymptomatic patients with COVID-19 are the key issues in future epidemic prevention and recovery. In this narrative review, we summarise the existing knowledge about asymptomatic patients and put forward detection methods that are suitable for finding such patients. Besides, we compared the characteristics and transmissibility of asymptomatic patients in different populations in order to find the best screening, diagnosis and control measures for different populations. Comprehensive preventive advice is also provided to prevent the spread of infection from asymptomatic patients.
High-affinity T-cell receptor specific for MyD88 L265P mutation for adoptive T-cell therapy of B-cell malignancies
Authors: Çınar Özcan , Brzezicha Bernadette , Grunert Corinna , Kloetzel Peter Michael , Beier Christin , Peuker Caroline Anna , Keller Ulrich , Pezzutto Antonio , Busse Antonia
Published: July 2021

Background

Adoptive transfer of engineered T cells has shown remarkable success in B-cell malignancies. However, the most common strategy of targeting lineage-specific antigens can lead to undesirable side effects. Also, a substantial fraction of patients have refractory disease. Novel treatment approaches with more precise targeting may be an appealing alternative. Oncogenic somatic mutations represent ideal targets because of tumor specificity. Mutation-derived neoantigens can be recognized by T-cell receptors (TCRs) in the context of MHC–peptide presentation.

Methods

Here we have generated T-cell lines from healthy donors by autologous in vitro priming, targeting a missense mutation on the adaptor protein MyD88, changing leucine at position 265 to proline (MyD88 L265P), which is one of the most common driver mutations found in B-cell lymphomas.

Results

Generated T-cell lines were selectively reactive against the mutant HLA-B*07:02-restricted epitope but not against the corresponding wild-type peptide. Cloned TCRs from these cell lines led to mutation-specific and HLA-restricted reactivity with varying functional avidity. T cells engineered with a mutation-specific TCR (TCR-T cells) recognized and killed B-cell lymphoma cell lines characterized by intrinsic MyD88 L265P mutation. Furthermore, TCR-T cells showed promising therapeutic efficacy in xenograft mouse models. In addition, initial safety screening did not indicate any sign of off-target reactivity.

Conclusion

Taken together, our data suggest that mutation-specific TCRs can be used to target the MyD88 L265P mutation, and hold promise for precision therapy in a significant subgroup of B-cell malignancies, possibly achieving the goal of absolute tumor specificity, a long sought-after dream of immunotherapy.
Statin-mediated inhibition of RAS prenylation activates ER stress to enhance the immunogenicity of KRAS mutant cancer
Authors: Nam Gi-Hoon , Kwon Minsu , Jung Hanul , Ko Eunbyeol , Kim Seong A , Choi Yoonjeong , Song Su Jeong , Kim Seohyun , Lee Yeji , Kim Gi Beom , Han Jihoon , Woo Jiwan , Cho Yakdol , Jeong Cherlhyun , Park Seung-Yoon , Roberts Thomas M. , Cho Yong Beom , Kim In-San
Published: July 2021

Background

Statins preferentially promote tumor-specific apoptosis by depleting isoprenoid such as farnesyl pyrophosphate and geranylgeranyl pyrophosphate. However, statins have not yet been approved for clinical cancer treatment due, in part, to poor understanding of molecular determinants on statin sensitivity. Here, we investigated the potential of statins to elicit enhanced immunogenicity ofKRAS-mutant (KRASmut) tumors.

Methods

The immunogenicity of treated cancer cells was determined by western blot, flow cytometry and confocal microscopy. The immunotherapeutic efficacy of mono or combination therapy using statin was assessed inKRASmuttumor models, including syngeneic colorectal cancer and genetically engineered lung and pancreatic tumors. Using NanoString analysis, we analyzed how statin influenced the gene signatures associated with the antigen presentation of dendritic cells in vivo and evaluated whether statin could induce CD8+ T-cell immunity. Multiplex immunohistochemistry was performed to better understand the complicated tumor-immune microenvironment.

Results

Statin-mediated inhibition ofKRASprenylation provoked severe endoplasmic reticulum (ER) stress by attenuating the anti-ER stress effect ofKRASmutation, thereby resulting in the immunogenic cell death (ICD) ofKRASmutcancer cells. Moreover, statin-mediated ICD enhanced the cross-priming ability of dendritic cells, thereby provoking CD8+ T-cell immune responses againstKRASmuttumors. Combination therapy using statin and oxaliplatin, an ICD inducer, significantly enhanced the immunogenicity ofKRASmuttumors and promoted tumor-specific immunity in syngeneic and genetically engineeredKRASmuttumor models. Along with immune-checkpoint inhibitors, the abovementioned combination therapy overcame resistance to PD-1 blockade therapies, improving the survival rate ofKRASmuttumor models.

Conclusions

Our findings suggest thatKRASmutation could be a molecular target for statins to elicit potent tumor-specific immunity.
Integrity and rights to gender-affirming healthcare
Authors: Cosker-Rowland Rach
Published: July 2021

Gender-affirming healthcare (GAH) interventions are medical or surgical interventions that aim to allow trans and non-binary people to better affirm their gender identity. It has been argued that rights to GAH must be grounded in either a right to be cured of or mitigate an illness—gender dysphoria—or in harm prevention, given the high rates of depression and suicide among trans and non-binary people. However, these grounds of a right to GAH conflict with the prevalent view among theorists, institutions and activists that trans and non-binary people do not have a mental illness and that one can be trans and entitled to GAH without being depressed or suicidal. This paper challenges the orthodoxy that a right to GAH must be grounded in either of these ways and instead argues for a right to GAH grounded in a right to live and act with integrity. The standard view, which this paper explains, is that our rights to live and act with integrity ground a right to religious accommodation in many cases such as a right to not be denied social security due to one’s refusal to work a job on a holy day. This paper argues that if our rights to live and act with integrity can groundprima facierights to religious accommodation, our rights to live and act with integrity groundprima facierights to GAH.
Analytical model and energy harvesting analysis of a vibrating slender rod with added tip mass in three-dimensional space
Authors: Borowiec Marek , Bochenski Marcin , Litak Grzegorz , Teter Andrzej
Published: July 2021

In the paper, a new 3D energy harvesting system is provided. This work discussed the Lagrange approach to derive the differential equations of motion in the case of energy harvesting systems. An electromechanical system consists of a mechanical resonator, a piezoelectric transducer and electrical circuit with the load resistor. A flexible slender rod clamped at the bottom and loaded by the tip mass is proposed as the resonator. Moving in the 3D space, it enables the system to avoid the gravitational potential barrier of the straight vertical shape in case of buckling. This paper investigates the response of the rod deflection and the root mean square power output of selected vibration mode shapes with an attached tip mass.
Quasi Z-Source Network-Based Photovoltaic Supported STATCOM for Voltage and Frequency Control of Stand-Alone WECS
Authors: Jeyanthi S. , Krishnamoorthi K.
Published: July 2021

This paper proposes a control scheme that enhances both the power quality and voltage synchronization of the Self-Excited Induction Generator (SEIG) driven by a wind turbine supplying power to a remote region. A reactive power constraint of SEIG under load disturbances is balanced by a modified Second-Order Generalized Integrator (SOGI) with Fuzzy Logical Controller (FLC) controlled Quasi-Impedance (QZ) source network-based Static Compensator (STATCOM). The combination of STATCOM and the photovoltaic system, battery and flywheel enhances the active power potential of conventional STATCOMs by means of a hybridized STATCOM system. This system is intended for the optimum use of energy generated from renewable energy sources by physical energy storage systems such as flywheels and batteries. This tends to compensate for the deviation of both active and reactive power and hence increase in active power, reliability and system stability. For analyzing device behavior, the dynamic hybrid STATCOM model with FLC dependent ESOGI has been developed. In standalone operation, simulated and experimental findings indicate the increased capability and system efficiency under variable load conditions.
Low Power Transposed Form 4-Tap Finite Impulse Response Filter Using Power Efficient Multiply Accumulate Unit
Authors: Rakesh S. , Grace K. S. Vijula
Published: July 2021

Finite impulse response (FIR) filters find wide application in signal processing applications on account of the stability and linear phase response of the filter. These digital filters are used in applications, like biomedical engineering, wireless communication, image processing, speech processing, digital audio and video processing. Low power design of FIR filter is one of the major constraints that researchers are trying hard to achieve. This paper presents the implementation of a novel power efficient design of a 4-tap 16-bit FIR filter using a modified Vedic multiplier (MVM) and a modified Han Carlson adder (MHCA). The units are coded using Verilog hardware description language and simulated using Xilinx Vivado Design Suite 2015.2. The filter is synthesized for the 7-series Artix field programmable gate array with xc7a100tcsg324-1 as the target device. The proposed filter design showed an improvement of a maximum of 57.44% and a minimum of 2.44% in the power consumption compared to the existing models.
Vortex-Induced Vibration and Countermeasure of a Tubular Transmission Tower
Authors: Fu Xing , Jiang Yao , Li Hong-Nan , Li Jia-Xiang , Xie Wen-Ping , Yang Li-Dong , Zhang Jian
Published: July 2021

Transmission towers with steel tubes or so-called tubular towers are widely used for ultra-high voltage (UHV) transmission because of their overall higher strength and stability, and better wind resistant capability. However, within a specific wind velocity range, tubular members with a high slenderness ratio are susceptible to joint fatigue failure under the vortex-induced vibration (VIV). To thoroughly unveil the mechanism of VIV of tubular members in UHV transmission towers, this paper first measures the acceleration and corresponding wind velocity of a tubular member under the VIV, followed by an identification of the first-order frequency. Then, a simulation framework for the tubular members subjected to the VIV is proposed. The system considered is simplified as a mass–spring–damping system with the non-linear coupling effect between the tubular member and wind field taken into account. Based on the analysis, the lock-in region and maximum displacement amplitudes in the cross-wind direction are calculated, while the simulation accuracy is verified via comparison with the on-site measured data. Meanwhile, the influence of damping ratio on the VIV is studied. Finally, a new type of radial spoiler is proposed to suppress the VIV of the tubular members. The results of the 3D simulation show that the proposed radial spoiler can effectively suppress the vortex generation, and there is no noticeable vibration after the installation of the countermeasure. In effect, it was demonstrated that the proposed countermeasure can effectively suppress the VIV of the tubular tower. The parametric analysis reveals that the distance between two adjacent spoilers has a significant impact on the control efficiency and should be carefully designed for each project.
IMPROVED ARTIFICIAL NEURAL NETWORK FOR EPILEPTIC SEIZURES DETECTION
Authors: BENCHAIB YASMINE
Published: July 2021

Electroencephalogram (EEG) is a fundamental and unique tool for exploring human brain activity in general and epileptic mechanism in particular. It offers significant information about epileptic seizures source known as epileptogenic area. However, it is often complicated to detect critical changes in EEG signals by visual examination, since this signal aspect of epileptic persons seems to be normal out of the seizure. Thus, the challenge is to design such a robust and automatic system to detect these unseen changes and use them for diagnosis. In this research, we apply the Artificial Metaplasticity Multi-Layer Perceptron (AMMLP) together with discrete wavelet transform (DWT) to Bonn EEG signals for seizure detection goal. Significant features were then extracted from the well-known EEG brainwaves. Aiming to decrease the computational time and improve classification accuracy, we performed a features ranking and selection employing the Relief algorithm. The obtained AMMLP classification accuracy of 98.97% proved the effctiveness of the applied approach. Our results were compared to recent researches results on the same database, proving to be superior or at least an interesting alternative for seizures detection within EEG signals.
Green Synthetic Fluorescent Carbon Quantum Dot as pH Sensor Applied to Real Water Samples Determination
Authors: Zhang Yong , Cheng Sijie , Xiao Yanteng , Wang Yingte
Published: July 2021

Willow, a common tree species, is mainly distributed in temperate regions of the Northern Hemisphere. Catkins are the seeds of willow. In addition to propagating new willows, it is of great significance to study its application in other areas. Carbon quantum dots (CQDs) have attracted extensive attention owing to their excellent luminescence properties, low toxicity and water solubility. The use of CQDs for accurate measurement of pH is of great significance in environmental, medical and other fields. Based on this, blue-emission fluorescent CQDs with 4.93% quantum yield (Q.Y.) are prepared via natural product catkins as the only raw material by one-step hydrothermal method. The prepared CQDs exhibit excellent water solubility, narrow particle size distribution, excitation-dependent photoluminescence properties and sensitive pH response behavior. The fluorescence intensity of CQDs has a good linear relationship with pH in the range of 6–12, and the correlation coefficient is 0.994. In addition, the CQDs have good stability, and the response to pH displays excellent reversibility, which can be developed as a pH sensor to quantitatively monitor the pH values in real water samples. Thereby, the potential practical application is promising.
Boundary Standoff and China-India Relations: A Chinese Scholar’s Perspective
Authors: Liu Zongyi
Published: July 2021

The China-Indian boundary and territorial dispute is one of the major issues affecting Sino-Indian bilateral relations. This issue was a legacy of the British colonialists, but unfortunately, it has been fully inherited by the Indian ruling class. Over the past 60 years, China and India have missed three opportunities to resolve this issue. The Indian ruling class wanted to achieve “absolute security” and therefore introduced a “forward policy”, which led to the 1962 conflict. After the war, India occupied almost all of the strategic commanding heights in the border area between the two countries by continuously encroaching on Chinese territory and pushing the Line of Actual Control (LAC) toward the Chinese side. After Prime Minister Modi came to power in 2014, he adopted the Doval Doctrine and “offensive defense” policy in the border area, with a view to continuing the encroachment on Chinese territory and occupying the strategic commanding heights. The aim was to force China to resolve the border issue in accordance with India’s intentions, so that India can then shift its strategic focus to the Indian Ocean. China-U.S. strategic rivalry and Hindu nationalism have fueled India’s behavior in the border region, and the peaceful resolution of the 2017 Donglang/Doklam standoff has emboldened India, making the bloodshed in Galwan Valley an inevitable incident. That India’s Home Minister Amit Shah categorically declared in August 2019 in Parliament that Aksai Chin was part of new Ladakh Union Territory shows that the Indian government has restored its position on the western sector boundary that the Vajpayee Administration had abandoned in 2003. India is using the Galwan conflict as an excuse to pursue its policy of economic de-Sinicization and strategic alliance with the U.S. and other Western countries. In the future, China-Indian border conflict is likely to become commonplace due to India’s expansionism.
Usages of Spark Framework with Different Machine Learning Algorithms
Authors: Ali Mohamed Mohamed , El-henawy Ibrahim Mahmoud , Salah Ahmad
Published: July 2021

Sensors, satellites, mobile devices, social media, e‐commerce, and the Internet, among others, saturate us with data. The Internet of Things, in particular, enables massive amounts of data to be generated more quickly. The Internet of Things is a term that describes the process of connecting computers, smart devices, and other data‐generating equipment to a network and transmitting data. As a result, data is produced and updated on a regular basis to reflect changes in all areas and activities. As a consequence of this exponential growth of data, a new term and idea known as big data have been coined. Big data is required to illuminate the relationships between things, forecast future trends, and provide more information to decision‐makers. The major problem at present, however, is how to effectively collect and evaluate massive amounts of diverse and complicated data. In some sectors or applications, machine learning models are the most frequently utilized methods for interpreting and analyzing data and obtaining important information. On their own, traditional machine learning methods are unable to successfully handle large data problems. This article gives an introduction to Spark architecture as a platform that machine learning methods may utilize to address issues regarding the design and execution of large data systems. This article focuses on three machine learning types, including regression, classification, and clustering, and how they can be applied on top of the Spark platform.
Shock Wave Propagation Characteristics of Cylindrical Charge and Its Aspect Ratio Effects on the Damage of RC Slabs
Authors: Zhao Xiaohua , Wang Gaohui , Fang Hongyuan , Fan Yong , Du Xueming
Published: July 2021

Antiknock research of reinforced concrete (RC) slabs is often carried out with spherical or nearly spherical explosives, although many explosives used in engineering and military are cylinder shaped. It is known that the shock wave caused by cylindrical explosives varies in different directions, which is quite different from the spherical charge. In this paper, the shock wave propagation characteristics of spherical and cylindrical explosives with different aspect ratios are compared and analyzed. The 2D numerical results show the peak overpressure from the cylindrical explosive is significantly affected by the L/D (length/diameter) ratio. Subsequently, the damage features of RC slabs under spherical and cylindrical explosives with a certain L/D ratio are investigated through an explosion experiment. Finally, the influence of the L/D ratio on the dynamic response of RC slabs under cylindrical explosives is studied by the fully coupled Euler–Lagrange method. The accuracy and reliability of the coupled model are verified by comparing the numerical with experimental results. Based on the experimental and numerical studies, it can be concluded that the explosive shape directly determines the shape of upper surface crater damage, and the spall damage area of RC slabs becomes larger as the L/D increases. For the L/D increases to a certain value, the cylindrical explosive will induce larger spall damage than that induced by spherical charge with the same amount of explosives. Hence, the effect of the cylindrical charge should be considered in the antiknock design of the RC structure.
The Crack Propagation Trend Analysis in Ceramic Rolling Element Bearing considering Initial Crack Angle and Contact Load Effect
Authors: Yuan Zhe , Wang Bohan , Liu Chao , Wang Zhan , Zhang Xiaochen , Zhang Yu
Published: July 2021

Silicon nitride ceramic bearings are widely used for their excellent performance. However, due to their special manufacturing method, cracks will occur on ceramic ball surface, and this initial surface crack will propagate under the action of cyclic stress, which will lead to material spalling. This will greatly limit its service life in practical applications, especially under heavy load at high speed. Therefore, it is necessary to study the surface crack propagation of silicon nitride ceramic bearings. In this paper, the effect of initial crack angle and contact load on crack growth is analysed by the finite element method (FEM). A three‐dimensional finite element model of a silicon nitride bearing ball containing an initial crack is created by the FEM. The cracks are initially classified based on the angle between the crack and the bearing ball surface, and the location of the most dangerous load for each type of crack is known by theoretical analysis. The stress intensity factors (SIFs) are calculated for the crack front to investigate the effect of load position on crack growth. Subsequently, the SIFs are calculated for each type of crack angle subdivided again to investigate the effect of crack angle on crack propagation.
Evaluation of Cyclic Fatigue of Hyflex EDM, Twisted Files, and ProTaper Gold Manufactured with Different Processes: An In Vitro Study
Authors: Khandagale Pooja D. , Shetty Prashant P. , Makandar Saleem D. , Bapna Pradeep A. , Karobari Mohmed Isaqali , Marya Anand , Messina Pietro , Scardina Giuseppe Alessandro
Published: July 2021

Introduction. The main aims of root canal instrumentation are to provide an environment that will lead to healing and to provide a root canal shape that is comfortable to clean and seal. When working with rotary endodontic instruments, the most significant concerns are that the instrument might fracture in the root canal, thus affecting the treatment outcome. Hence, it is of immense importance to know which file systems have more cyclic fatigue resistance. Methodology. This study evaluated the effect of the curved segment length of the artificial canal (the arch), and the number of cycles necessary in fracture of Hyflex EDM, Twisted files, and ProTaper Gold were recorded. Sixty NiTi rotary instruments of 25 mm length (Hyflex EDM (20), Twisted files (20), and ProTaper Gold (20)) were tested in a metal block with simulated canal having 90° angle of curvature. The study was performed with a specific radius and degree of curvature, i.e., 8 mm radius and 90⁰ angle of curvature, and data obtained were subsequently subjected to statistical evaluation using one-way analysis of variance and Tukey’s post hoc test. Result. The Hyflex EDM (774.29) exhibited the maximum cyclic fatigue resistance compared to Twisted files (654.875) and ProTaper Gold (375.575). A statistically significant difference was observed between the tested groups. Conclusion. The Hyflex EDM files showed the highest cyclic fatigue resistance, followed by Twisted files and ProTaper Gold files.
Study on Seismic Response and Damping Measures of Surrounding Rock and Secondary Lining of Deep Tunnel
Authors: Tang Baoli , Ren Yongqiang
Published: July 2021

Tunnel construction is gradually developing to areas with high in situ stress; the deeper the tunnel construction, the more intense the earthquake disturbance. Under the background of frequent earthquakes, the seismic characteristics of tunnels become an important content related to the safety and stability of engineering structures. In view of the key problems of seismic response and vibration reduction measures for complex deep buried tunnels, the methods of advanced grouting and foam concrete aseismic are studied in this paper. Firstly, through geological survey, the in situ stress and geological conditions of the study area are analyzed. The structural characteristics of surrounding rock and related rock mechanics parameters are analyzed. The failure criterion of concrete lining under dynamic load is studied theoretically, and the relevant numerical calculation parameters are modified. A numerical model based on viscous boundary conditions is established. Through numerical calculation, the seismic response of tunnel surrounding rock and lining under different damping measures is analyzed. The research results have theoretical research value and social and economic benefits for ensuring the safety and stability of tunnel structure and improving the seismic fortification level.