bluuebunny/crossref_metadata_2025 huggingface dataset:
A Review on Combining Micro Gas Turbines with Organic Rankine Cycles
Authors: Bonolo de Campos Gustavo , Bringhenti Cleverson , Traverso Alberto , Takachi Tomita Jesuino
Published: August 2019

Current energy conversion machines such as the micro gas turbine can be improved by harvesting the low-grade energy of the exhaust. A prominent option for such is the organic Rankine cycle due to its relatively efficient and reliable design. This manuscript presents a review on the subject and is the first step toward the design of an organic Rankine cycle bottoming a 100 kWe recuperated gas turbine. After introducing and covering the historical development of the technology, appropriate guidelines for defining the cycle arrangement and selecting the fluid are presented. At last, the viability of the cycle is assessed by assuming an appropriate efficiency value and general cost functions. The organic Rankine is expected to generate an additional 16.6 kWe of power, increasing the electrical efficiency from 30 to 35%. However, the capital cost increase was estimated in 48%.
Do separated taxa react differently to a long-term salinity increase? The meiobenthos changes in Bay Sivash, largest hypersaline lagoon worldwide
Authors: Shadrin Nickolai , Kolesnikova Elena , Revkova Tatiana , Latushkin Alexander , Chepyzhenko Anna , Drapun Inna , Dyakov Nikolay , Anufriieva Elena
Published: August 2019

In the world's largest hypersaline lagoon Bay Sivash, its ecosystem twice transformed from a previous state to a new one due to human intervention. Before the North Crimean Canal construction, it was hypersaline (average salinity of 140 g l−1). The canal was built between 1963 and 1975, which resulted in intensive development of irrigated agriculture discharging drainage water into the bay. Between 1988 and 2013, salinity gradually dropped to average of 18–23 g l−1; a new ecosystem with a different biotic composition formed. In April 2014, the supply of Dnieper water into the North Crimean Canal ceased. This resulted in a gradual salinity increase in the bay to an average of 52 g l−1in 2015. The start of second ecosystem shift was observed in 2015. In 2018, TSS, DOM and meiobenthos were studied in a salinity gradient from 30 to 88 g l−1. There was an increase in TSS and DOM with increasing salinity. The meiobenthos structure was significantly different in the bottom community and floating mats of filamentous green algae. No correlation was recorded between the number of meiobenthic macrotaxa in the sample and salinity. From 2013 to 2018, changes were seen in the taxocene structure of Nematoda and Harpacticoida. Changes in Nematoda were more dramatic and prolonged than in Harpacticoida. The structure of the Harpacticoida and Ostracoda taxocenes are less variable and more stable than that of the Nematoda taxocene. One of the reasons may be more mobility of Harpacticoida/Ostracoda than Nematoda and/or better osmoadaptation mechanisms.
Examination of high school students' attitudes towards homework, procrastination behaviors and efficacy beliefs
Authors: Altundağ Canan Koçak
Published: August 2019

The aim of this study was to examine the relationship between high school students' academic procrastination behaviors, efficacy beliefs, and attitudes towards homework. This study has shown that students with low academic and/or social efficacy belief engage in more academic procrastination behavior than those with high academic and/or social efficacy belief and that students with high academic, social, and/or emotional efficacy belief have a more positive attitude towards homework than those with low academic, social, and/or emotional efficacy belief. There was no significant statistical difference in academic procrastination behavior based on low or high emotional efficacy belief. This study examines the relationship between high school students' efficacy beliefs, academic procrastination behaviors, and their attitude towards homework in order to address the fact that in the literature there was no study on the correlation between efficacy belief and both academic procrastination and attitude towards homework.
The effect of learning approaches on prospective chemistry teachers' self-regulated learning skills: The survey research
Authors: Özgür Sinem Dinçol
Published: August 2019

The purpose of this research was to examine the effect of the learning approaches on prospective chemistry teachers' self-regulated learning skills. 92 prospective chemistry teachers from the Department of Chemistry Education at one of the public university in Turkey participated in the research. “The Study Process Questionnaire” and “Self-regulated Learning Skills Scale” were used as the data collection tools. It was consequently found that 59.8 % of prospective chemistry teachers adopted deep learning approach, 40.2% of them adopted surface learning approach and their self-regulated learning skills scale scores for planning and goal setting scores differed significantly according to their learning approaches. Furthermore, it was determined that self-regulated learning skills mean score of prospective teachers' who adopted deep approach are higher than mean score of prospective teachers' who adopted surface approach but their self-regulated learning skills total scores did not differ significantly according to their learning approaches.
Opinions of teacher candidates upon the use of effective communication skills when teaching sciences
Authors: Çıldır Sema
Published: August 2019

While teaching sciences which takes up a huge place in today's technological world, effective communication among teachers and students is especially required in order to increase the enthusiasm of students about sciences. The study is aimed to support teacher candidates in acquiring effective interaction abilities, which are some of the 21st century foreground skills, and foster them to make use of these abilities in the process of teaching sciences. The research has been conducted in accordance with qualitative research techniques which include observation and semi- structured interviewing techniques. 17 teacher candidates have taken part in the research as volunteers. The result of the observations made show that these teacher candidates have used oral communication in the activities mostly. The subject of hand and facial movements (mimics) and drama technique in teaching have drawn attention of teacher candidates heavily. According to the results of interviews made, it can be deducted that it is an important improvement for them to learn effective listening is also a medium for communication. At the end of the research, the teacher candidates have been observed to have found a chance to get to know themselves in the use of communication skills; therefore, it has been detected these people have been using some of the communication channels without realizing it, whether they are positive or negative, in their relations with friends, family members, school life and so on. The realization of teacher candidates upon the importance of communication skills in education and turning their ideas into skills through their knowledge in the issue reveal the fact that this study has fulfilled its aims.
Phase Angle is Moderately Associated with Short-term Maximal Intensity Efforts in Soccer Players
Authors: Nabuco Hellen C. G. , Silva Analiza M. , Sardinha Luís B. , Rodrigues Felipe B. , Tomeleri Crisieli M. , Ravagnani Fabrício C. P. , Cyrino Edilson S. , Ravagnani Christianne F. C.
Published: August 2019

This study examined the relationship between PhA and short-term maximal intensity efforts in soccer players, and was conducted in 99 male soccer players, ages 19–36 years. Bioelectrical impedance was used to assess body fat, fat free mass (FFM) and PhA (phase angle). Running Anaerobic Sprint Test (RAST) was used to evaluate physical performance. Food consumption was assessed through the 24-hour dietary recall method. Pearson correlation and multiple regressions were used for statistical analysis. Phase angle exhibited a positive relationship with maximum power (β=0.66; P<0.001), even after adjustment for the co-variables FFM and body fat (β=0.52; P=0.02). Phase angle was inversely related with fatigue index (β=− 0.61; P=0.04), even after adjusting for FFM (β=− 0.70; P=0.020). Our results indicated that independently of FFM and body fat, PhA was inversely associated with fatigue index and positively related with maximum power, revealing the PhA appeared as a valid predictor of fatigue.
Nonviral Sexually Transmitted Diseases
Authors: Cologne Kyle G. , Hsieh Christine
Published: August 2019

This article provides a practical overview for the management of nonviral sexually transmitted diseases affecting the perianal and anorectal regions. Clinical manifestations, diagnosis, and treatment of syphilis, gonorrhea, chancroid, donovanosis, and lymphogranuloma venereum are individually addressed.
Premalignant and Malignant Perianal Lesions
Authors: Abbass Mohammad Ali , Valente Michael A.
Published: August 2019

Anal cancer is a heterogeneous and rare disease process that accounts for ∼1.5% of all gastrointestinal tract malignancies. The perianal skin plays host to a variety of different premalignant and malignant lesions, all with variable histology, treatment options, and prognosis. Anal cancers in general are notorious for having a delayed or missed diagnosis leading to treatment delays and may have an impact on survival. This delay is in part due to the nonspecific symptomatology and also improper physical examination of the sensitive and anatomically complex perianal region and anal canal. This article examines the various types of perianal cancers and their precursor lesions and will explore treatment options as well as outcomes and prognosis.
Miscellaneous Perianal Afflictions
Authors: Hagerman Gonzalo F. , Silva-Velazco Jorge , Molina-Lopez Juan Francisco
Published: August 2019

This article provides an overview of hidradenitis suppurativa, lichen planus, lichen sclerosis, calcinosis cuti, pyogenic granuloma, intertrigo, and seborrheic keratosis. This article also focuses on recognition and management of these pleomorphic afflictions of the perianal region.
From Burnout to Well-Being: A Focus on Resilience
Authors: Mahmoud Najjia N. , Rothenberger David
Published: August 2019

Burnout is a widespread problem in health care. Factors that contribute to enhancing engagement and building resiliency are widely discussed, but the data supporting these practices are not well understood. Interventions aimed at increasing engagement and promoting resiliency are targeted toward individual practitioners, health care institutions, and national organizations. Knowledge of the data supporting various kinds of interventions is vital to implementing change meaningfully. Prevention of burnout should start early in training with appropriate modeling and input from mentors and should incorporate stress management strategies. The most compelling data for building resilience requires institutions, physicians, and their support staff to align their values to create a mutual culture of wellness and engagement. It is imperative that institutional and national reform allows us as physicians to preserve our relationships with patients and colleagues, while also prioritizing time to reflect and pursue outside interests that recharge and restore.
The Pregnant Surgeon
Authors: Harnsberger Cristina R. , Davids Jennifer S.
Published: August 2019

The proportion of women entering medicine and surgery is increasing steadily. As more women surgeons have children during residency and practice, it is essential that we adopt a team approach to the pregnant surgeon, as a pregnancy undoubtedly impacts the team and not just the individual. Coauthored by a practicing surgeon mother of 2 (J. D.) and a postgraduate year 8 colorectal surgery fellow mother of 2 who is currently pregnant (C. H.), we aim to review the data while providing some practical advice for pregnant surgeons and those considering pregnancy, as well as their valued colleagues, mentors, and administrators. Physical challenges are discussed by trimester, as are the risks facing the pregnant surgeon, the logistics of transitioning in and out of maternity leave, and postpartum considerations.
Ergonomics and Musculoskeletal Health of the Surgeon
Authors: Schlussel Andrew T. , Maykel Justin A.
Published: August 2019

Surgeons face hazardous working conditions due to ergonomic deficiencies found throughout the operating room. More than 80% of surgeons have succumbed to a work-related injury or illness as a consequence of sustaining awkward or static positions throughout lengthy operations over a career. While the focus of the procedure is directed to the patient, there is little concurrent regard for proper posture or spinal stability. Even when symptoms of discomfort are experienced, they are often ignored. This results in decreased production and may ultimately threaten surgical careers. Surgeons are often unaware of recommendations or guidelines designed to improve their comfort while operating. Furthermore, there is a significant lack of any formal ergonomic education, especially for minimally invasive procedures. Several modifiable risk factors can be adjusted in the operating room to provide a safer working environment. In addition, strengthening, stability, and exercise programs directed by a trained therapist may be employed to improve the surgeon's musculoskeletal health.
Pediatric Lymphangiography: Imaging to Intervention
Authors: Lee Shimwoo , Luhar Aarti P. , Lee Edward Wolfgang , Sinha Sanjay , Srinivasa Ravi N.
Published: August 2019

The lymphatic system plays a crucial role in fluid transport as well as facilitating immune recognition. Disruption of lymphatic flow can lead to significant morbidity and mortality in the pediatric population, manifesting as lymphatic malformations and lymphatic leaks. There has been rising interest in developing minimally invasive image-guided approaches to diagnose and treat lymphatic disorders in pediatric patients. Notably, magnetic resonance imaging of the lymphatic system has emerged as a promising diagnostic tool. Moreover, interventions such as sclerotherapy and thoracic duct embolization for treatment of lymphatic malformations and leaks have come forth as safe and effective alternatives to surgery. The aim of this article is to review various pediatric lymphatic disorders and discuss advances in image-guided diagnostic and therapeutic options for these entities.
A Lie transform approach to the construction of Lyapunov functions in autonomous and non-autonomous systems
Authors: Fortunati Alessandro , Wiggins Stephen
Published: August 2019

This paper deals with the well-known problem of constructing Lyapunov functions for a nonlinear system and the approximation of the basin of attraction associated with a given attractive equilibrium point. Following a paper by Spelberg-Korspeter et al., the problem is studied by means of perturbative methods, with particular focus on the time-reversed Van Der Pol model. As a difference, the theory is reformulated in terms of the Lie transform method, introduced by Giorgilli et al., which, remarkably, does not require any inverse function arguments to produce the inverse transformations during the normalization process. This will be shown to be, also in this case, a key feature in terms of concrete applications. The nonautonomous perturbation theory developed by the authors in previous works allows an effortless extension of such a construction to the (aperiodically) time-dependent case.
In vivo evaluation of two-dimensional temperature variation in perirenal fat of pigs with B-mode ultrasound
Authors: Fan Pengfei , Yin Chuhao , Xue Honghui , Xie Linzhou , Sun Wei , Tu Juan , Guo Xiasheng , Kong Xiangqing , Zhang Dong
Published: August 2019

Benefiting from their minimally or noninvasive nature, thermal therapies are becoming increasingly important in tumor treatment, in which real-time monitoring of in vivo temperature based on ultrasonic imaging has shown great promise. In this work, an improved dynamic frame selection algorithm and a modified adaptive filtering method were combined with a thermal expansion model, and in vivo temperature monitoring with improved accuracy was achieved. The ultimate aim being the use of thermometry in the thermal treatment of hypertension, experiments targeting the perirenal fat of living pigs were carried out, in which microwaves were applied as a heat source at different power levels. By comparing the echo shift of the ultrasound (US) and the temperature—sensed via a thermocouple—a constant temperature evaluation coefficient was determined. As the tissue was raised to 6.4, 9.8, and 19.3 °C above its base temperature, the root-mean-square evaluation error (ɛrms) was about 0.3, 0.5, and 0.8 °C, respectively. High precision and a high signal-to-noise ratio can help US thermometry play a more important role in monitoring the application of thermal therapies.
High thermal stability of piezoelectric properties in tetragonal Pb(In1/3Nb2/3)O3-PbTiO3 single crystal
Authors: Deng Chenguang , He Chongjun , Chen Ziyun , Chen Hongbing , Mao Rong , Liu Youwen , Zhu Kongjun , Gao Huifang , Ding Ye
Published: August 2019

The representatives of relaxor ferroelectric (1-x)Pb(Zn1/3Nb2/3)O3-xPbTiO3 (PZNT) and (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMNT) have been extensively studied due to their excellent dielectric and piezoelectric properties near the morphotropic phase boundary (MPB). However, low rhombohedral to tetragonal phase transition temperature and Curie temperature directly affect the performance and stability of devices, particularly for high-power ultrasonic transducers. In this paper, the large size tetragonal 0.62Pb(In1/2Nb1/2)O3-0.38PbTiO3 (PINT) crystal was grown by the modified Bridgman technique. The crystals were oriented along the ⟨100⟩ direction to make bars with electrodes on (001) faces. The variation of the dielectric constant with temperature showed that the Curie temperature of PINT was 250 °C, and the maximum dielectric constant was 7.29 × 104 ɛ0. Fitting with Curie-Weiss’s law, we obtained that the relaxation degree was 1.44, which could mean that the dielectric properties of PINT are between relaxor ferroelectric and ordinary ferroelectric. At room temperature, electromechanical coupling coefficient k31 and piezoelectric strain constant d31 were 0.56 and 551 pC/N, respectively. Piezoelectric properties were relatively stable between room temperature and 175 °C. The material has good temperature stability in terms of piezoelectricity and dielectric properties. These results proved that the working temperature of the PINT crystal could reach about 175 °C, much higher than PZNT and PMNT single crystal, indicating their application in ultrasonic transducers at high temperatures.
Resilience for stochastic systems interacting via a quasi-degenerate network
Authors: Nicoletti Sara , Fanelli Duccio , Zagli Niccolò , Asllani Malbor , Battistelli Giorgio , Carletti Timoteo , Chisci Luigi , Innocenti Giacomo , Livi Roberto
Published: August 2019

A stochastic reaction-diffusion model is studied on a networked support. In each patch of the network, two species are assumed to interact following a non-normal reaction scheme. When the interaction unit is replicated on a directed linear lattice, noise gets amplified via a self-consistent process, which we trace back to the degenerate spectrum of the embedding support. The same phenomenon holds when the system is bound to explore a quasidegenerate network. In this case, the eigenvalues of the Laplacian operator, which governs species diffusion, accumulate over a limited portion of the complex plane. The larger the network, the more pronounced the amplification. Beyond a critical network size, a system deemed deterministically stable, hence resilient, can develop seemingly regular patterns in the concentration amount. Non-normality and quasidegenerate networks may, therefore, amplify the inherent stochasticity and so contribute to altering the perception of resilience, as quantified via conventional deterministic methods.
Temperature dependence of carrier scattering in polycrystalline bismuth
Authors: Arisaka Taichi , Otsuka Mioko , Tokitani Masayuki , Hasegawa Yasuhiro
Published: August 2019

The dependence of the scattering process on temperatures ranging from 50 to 300 K was comprehensively investigated by measuring five transport coefficients (resistivity, magnetoresistivity, Seebeck coefficient, Hall coefficient, and Nernst coefficient) using polycrystalline bulk bismuth. The values of five physical properties (carrier density, electron and hole mobilities, and electron and hole Fermi energies) were calculated assuming that carrier scattering ranged from acoustic deformation potential scattering to ionized impurity scattering. The accompanying mean-free paths of carriers were also evaluated using the calculated Fermi energy and the effective mass tensor. The mean-free path and grain size (typically several micrometers) obtained from electron backscattered diffraction helped narrow the distribution range of the different scattering processes. Thus, the physical properties, including temperature dependence of the scattering processes, were recalculated, and realistic temperature dependence of the electron mobility was assumed. Quantitative and qualitative analyses showed that near room temperature, acoustic deformation potential scattering dominated, which changed to ionized impurity scattering when the estimated mean-free path exceeded 1 μm. This indicated that the scattering process of polycrystalline bulk bismuth depends on the grain size when the measurement results of the Nernst coefficient related to the scattering process are directly used. The bandgap energy of bismuth was also calculated, and the temperature dependence of the scattering process was estimated. The results showed that the temperature dependence tendency of bandgap energy is similar to that described in the literature. Finally, this study provides the temperature dependence of the physical properties of polycrystalline bismuth.
High power GaInNAs superluminescent diodes emitting over 400 mW in the 1.2 μm wavelength range
Authors: Aho A. T. , Viheriälä J. , Virtanen H. , Zia N. , Isoaho R. , Guina M.
Published: August 2019

A high-power superluminescent diode emitting over 400 mW in the 1.2 μm range is reported. The active region is based on a single GaInNAs/GaAs quantum well positioned within a low-confinement vertical waveguide and a lateral ridge waveguide geometry, ensuring single transverse mode operation. The peak wall-plug efficiency and the differential efficiency in the linear region were 22.8% and 0.38 W/A, respectively. The full width at half-maximum spectral width for the maximum output power was 22 nm, corresponding to a spectral power density of 19 mW/nm, a threefold increase compared to continuous wave superluminescent diodes based on a quantum dot active region operating in the same wavelength range. Besides exhibiting excellent optical and electrical properties, the GaInNAs active region enhances operation at elevated temperatures. In this respect, an output power of about 210 mW is demonstrated at operation temperatures as high as 60 °C, while 150 mW is still emitted at 70 °C. The unique combination of parameters demonstrated makes these GaInNAs QW-based superluminescent diodes particularly attractive for hybrid integration with silicon photonic circuitry, enabling the demonstration of compact solutions for sensing, optical coherence tomography, and other emerging concepts exploiting photonic integration technology and requiring single transversal mode operation, good efficiency, broadband high spectral power density, and uncooled operation at elevated temperatures.
Improvement of the homogeneity of magnetic field by the attenuation of a selected component with an open superconducting shield made of commercial tapes
Authors: Tomków Łukasz , Kulikov Evgeniy , Kozłowski Kamil , Drobin Valeriy
Published: August 2019

Homogeneous magnetic fields are needed in many applications. The resolution of medical imaging techniques depends on the quality of the magnetic field, as does the efficiency of electron cooling systems used at particle accelerators. Current methods of improving homogeneity require complex arrangements of magnet windings. In this work, the application of commercial superconducting tapes for this purpose is analyzed experimentally and numerically. The shielding effect exhibited by the superconductors can be used to control the shape of the magnetic field. An open magnetic shield made of superconducting tapes is able to nullify the radial component of a solenoidal magnetic field, forming the long region of the homogeneous magnetic field. To form a shield, the superconducting tapes are wound on a former. Then, it is positioned coaxially inside an electromagnet. The measurements are performed in the DC magnetic field and at zero-field cooling conditions. A numerical model is developed to further analyze the magnetic field. New simplifications and proper constraints allow the use of an axial symmetry despite relatively complex geometry of the shields. Results from the simplified model and obtained experimentally are consistent. The decrease of radial component of the magnetic field and the significant improvement of its homogeneity are observed in a shielded region. The decrease of shielding quality with the increase of an applied magnetic field is observed. Empirical formulas describing the dependence of shielding quality on the geometry and the critical current of the shield are developed.
Noncoalescent liquid metal droplets sustained on a magnetic field-circulated liquid metal bath surface
Authors: Zhao Xi , Yang Lixiang , Ding Yujie , Zhang Pengju , Liu Jing
Published: August 2019

When exerting a rotating magnetic field on a liquid metal bath, the bath is driven to flow toward the magnetic field direction through the induced Lorentz force. Past a critical speed, a stable ring-shaped bath configuration is formed, and a droplet of the same liquid metal can persistently move without coalescence on the bath surface with a lubricating NaOH solution film between the two liquid metal bodies. The lubricating film allows the levitating droplet to rotate in the direction of the magnetic field. The magnetic field induced noncoalescence effect provides a noninvasive method to manipulate and study liquid metal droplet behavior on a soft substrate.
First-principles study of Pt doping effects on Ni2MnGa and Ni2FeGa ferromagnetic shape memory alloys
Authors: Yang Xiong , Wang Ying , Du Mingrun , Xue Yanhong
Published: August 2019

The influence of Pt doping on the lattice structure, magnetism, elastic moduli, and martensite transition of Ni2MnGa and Ni2FeGa Heusler alloys was studied using first-principles calculations. We investigated Pt substitution at all three different sites of Ni, Mn (Fe), and Ga with different concentrations. Partial Pt substitution at the Ni and Ga sites appeared to strengthen the ferromagnetism of these two alloys, whereas increasing the Pt content at the Mn (Fe) site weakened the total magnetic moment significantly. Pt doping at the three sites was conducive to austenite-martensite transformation, and the martensitic transition temperature TM increased with increasing Pt concentration, especially for the replacement of Ga by Pt. Most Pt-doped Ni2MnGa and Ni2FeGa alloys follow the general rule regarding the tetragonal shear modulus C′ and TM: a softening of C′ corresponds to an increase of TM. Unlike the case of Pt occupation at the Ga site, substantial Pt substitution at the Ni and Mn (Fe) sites led to a remarkable decrease in the inherent brittleness of Ni2MnGa and Ni2FeGa and thus promoted their technological application.
An in situ high-throughput screen identifies inhibitors of intracellular
Burkholderia pseudomallei
with therapeutic efficacy
Authors: Bulterys Philip L. , Toesca Isabelle J. , Norris Michael H. , Maloy Jeffrey P. , Fitz-Gibbon Sorel T. , France Bryan , Toffig Babak , Morselli Marco , Somprasong Nawarat , Pellegrini Matteo , Schweizer Herbert P. , Tuanyok Apichai , Damoiseaux Robert , French Christopher T. , Miller Jeff F.
Published: August 2019

Significance

Burkholderia pseudomallei
, the etiologic agent of melioidosis, is an environmental organism that inhabits tropical soils and kills an estimated 90,000 people each year. Caused by an intracellular and often drug-resistant pathogen, melioidosis is notoriously difficult to treat, with mortality rates approaching 50% in some settings despite appropriate diagnosis and clinical management. Using a high-throughput, cell-based phenotypic screen we have discovered 2 antibiotic candidates with improved in vivo efficacy compared to the current standard of care: a fluoroquinolone analog, burkfloxacin, and an FDA-approved antifungal drug, flucytosine. As a widely used antifungal with a well-known safety profile, the potential to repurpose flucytosine for treating melioidosis may represent a rapid route to clinical translation.
Directionality reduces the impact of epidemics in multilayer networks
Authors: Wang Xiangrong , Aleta Alberto , Lu Dan , Moreno Yamir
Published: August 2019

Our understanding of how diseases spread has greatly benefited from advances in network modeling. However, despite of its importance for disease contagion, the directionality of edges has rarely been taken into account. On the other hand, the introduction of the multilayer framework has made it possible to deal with more complex scenarios in epidemiology such as the interaction between different pathogens or multiple strains of the same disease. In this work, we study in depth the dynamics of disease spreading in directed multilayer networks. Using the generating function approach and numerical simulations of a stochastic susceptible-infected-susceptible model, we calculate the epidemic threshold of synthetic and real-world multilayer systems and show that it is mainly determined by the directionality of the links connecting different layers, regardless of the degree distribution chosen for the layers. Our findings are of utmost interest given the ubiquitous presence of directed multilayer networks and the widespread use of disease-like spreading processes in a broad range of phenomena such as diffusion processes in social and transportation systems.
Elastic properties of anatase titanium dioxide nanotubes: A molecular dynamics study*
Authors: Yang Kang , Yang Liang , Ai Chang-Zhi , Wang Zhao , Lin Shi-Wei
Published: August 2019

The elastic properties of anatase nanotubes are investigated by molecular dynamics (MD) simulations. Youngʼs modulus, Poisson ratio, and shear modulus are calculated by transversely isotropic structure model. The calculated elastic constants of bulk rutile, anatase, and Youngʼs modulus of nanotube are in good agreement with experimental values, respectively, demonstrating that the Matsui and Akaogi (MA) potential function used in the simulation can accurately present the elastic properties of anatase titanium dioxide nanotubes. For single wall anatase titanium dioxide nanotube, the elastic moduli are shown to be sensitive to structural details such as the chirality and radius. For different chirality nanotubes with the same radius, the elastic constants are not proportional to the chiral angle. The elastic properties of the nanotubes with the chiral angle of 0° are worse than those of other chiral nanotubes. For nanotubes with the same chirality but different radii, the elastic constant, Youngʼs modulus, and shear modulus decrease as the radius increases. But there exist maximal values in a radius range of 10 nm–15 nm. Such information can not only provide a deep understanding of the influence of geometrical structure on nanotubes mechanical properties, but also present important guidance to optimize the composite behavior by using nanotubes as the addition.
Dynamic facilitation theory: a statistical mechanics approach to dynamic arrest
Authors: Speck Thomas
Published: August 2019

The modeling of supercooled liquids approaching dynamic arrest has a long tradition, which is documented through a plethora of competing theoretical approaches. Here, we review the modeling of supercooled liquids in terms of dynamic ‘defects’, also called excitations or soft spots, that are able to sustain motion. To this end, we consider a minimal statistical mechanics description in terms of activate regions with the order parameter related to their typical size. This is the basis for both Adam–Gibbs and dynamical facilitation theory, which differ in their relaxation mechanism as the liquid is cooled: collective motion of more and more particles versus concerted hierarchical motion over larger and larger length scales. For the latter, dynamic arrest is possible without a growing static correlation length, and we sketch the derivation of a key result: the parabolic law for the structural relaxation time. We critically discuss claims in favor of a growing static length and argue that the resulting scenarios for pinning and dielectric relaxation are in fact compatible with dynamic facilitation.
Centrifugal Pump Bearing Fault Diagnose Based on Time-Frequency Domain Analysis and BP-Neural Network
Authors: Chaowei Wang , Guojing Zhou , Qian Wu , Lvhui Ding , Yi Wei
Published: August 2019

Fault refers to the loss of function of equipment during operation. When a fault occurs, the equipment would usually show some surface features, which can be also called fault signals. Thus, the faults of the equipment can be diagnosed by deep analysis. Among the mechanical and electrical products, the centrifugal pump is one of the most typical ones, which has the majority characteristics of equipment in various kinds of ordnance. Through the study of centrifugal pump fault diagnose, the route of diagnose of mechanical and electrical products and the establishment of diagnose system can be clarified. In the study, the composition and function of centrifugal pump is firstly introduced. So is the fault diagnose system. Then the concept of the fault diagnose experiment is given. The data gathered by the diagnose system are processed in time and frequency domain. The BP- neural network is also applied to analyse the pump’s fault which is injected during the experiment. The analysis result reveals that the BP- neural network can effectively estimate the condition of centrifugal pump and distinguish the different fault modes.
Coupled Inductance Three-Level Cuk Converter
Authors: Ding Xin-ping , Yu Lei , Yu Dai-ling , Zhang Hong-xing
Published: August 2019

A three-level Cuk converter with coupled inductance is proposed in this paper. Based on the research and design of existing three-level Cuk converter and Cuk converter with coupling inductance, this paper combines three-level technology with coupling inductance, which is called the “three-level coupled inductance Cuk converter” in this paper[1-3]. Compared with the existing converter, it has the advantages of boost capability and energy conversion efficiency. This kind of converter integrates the low voltage stress of the switch with three-level DC-DC converter and the boost function of the DC-DC converter with coupling inductance[4-6]. The three-level structure reduces the voltage stress when the switch is turned off, while the coupling inductance structure greatly improves the boost capability of the circuit. The working principle and periodic mode of three-level coupled inductor Cuk circuit are analysed, and the mathematical formula of voltage gain is deduced.
Study on Penetration Resistance of Ceramic Composite Armor under Different Contact Stiffness
Authors: Feng Li , Quan Shi , Cai Chen
Published: August 2019

The finite element software ANSYS/LS-DYNA is used to simulate the penetration of tungsten alloy long rod projectile into ceramic composite armor. The penetration effect of tungsten alloy long rod projectile penetrating ceramic composite armor was obtained under different contact stiffness. At the same time, the theoretical model is used to calculate the residual velocity of tungsten alloy long rod projectile. It is found that the simulation results and theoretical calculation results are better.According to the fitting of simulation data, the relationship between penetration depth and loss velocity and incident velocity is obtained according to the different contact stiffness. It will provide some reference and reference value for studying the penetration effect of tungsten alloy long rod projectile on ceramic composite armor at a certain speed.
A Comparison of Feature Selection Methodology for Solving Classification Problems in Finance
Authors: Xiaomao Xia , Xudong Zhang , Yuanfang Wang
Published: August 2019

Classification is one of the most important tasks in real world with the intention of finding the underlying patterns of the data and making use of the found patterns. Other than considering lots of parameters that may influence the classification model accuracy, the influence of the feature selections has been rarely discussed. SHAP (SHapley Additive exPlanation) value is a novel ensemble learning measurement that is the unique consistent and locally accurate attribution value. Its applications to feature selection are not mentioned in the literature. In this paper, we compare the prediction accuracy of several feature selection techniques on a set of Polish companies. We show that new feature selection method based on the SHAP values is superior (not worse) to other widely used prediction methods.
Exploiting Meta-Path with Attention Mechanism for Fine-Grained User Location Prediction in LBSNs
Authors: Wang Zhixiao , Yan Wenyao , Wang Wendong , Gao Ang , Yu Lei , Yang Shaobo , Nie GaoYang
Published: August 2019

Based on the huge volumes of user check-in data in LBSNs, users’ intrinsic mobility patterns can be well explored, which is fundamental for predicting where a user will visit next given his/her historical check-in records. As there are various types of nodes and interactions in LBSNs, they can be treated as Heterogeneous Information Network (HIN) where multiple semantic meta-paths can be extracted. Inspired by the recent success of meta-path context based embedding techniques in HIN, in this paper, we design a deep neural network framework leveraging various meta-path contexts for fine-grained user location prediction. Experimental results based on two real-world LBSN datasets demonstrate the best effectiveness of the proposed approach using various evaluation metrics than others.
SSUP-Growth: A Novel Mining High Utility Algorithm Itemset with Single-Scan of Database
Authors: Alhusaini Naji , Jing Li , Hawbani Ammar , Alhusaini Abdullah
Published: August 2019

High Utility Itemset Mining (HUIM) alludes to the identification of itemsets of high utility in the value-based database UP-Growth algorithm is a standout amongst the best algorithms for overcome the challenge of candidate generation and scan database reputedly of previous algorithms. However, it needs scan database twice to actualize the UP tree. Regarding of the updating existing data with new information, UP-growth needs for twofold scanning of new information and existing information. The fundamental motivation behind this work is to build up another algorithm, Single-Scan Utility Pattern Tree (SSUP-tree), for mining high utility itemsets from transaction database through only single-scan of database. In our algorithm, the details of high-utility itemsets is preserved in a particular data structure of the SSUP-Tree after a single-scan of database. Consequently, it can retrieve the identical UP-tree with a fixed minimum utility threshold. The proposed algorithm required to scan the new data only to update SSUP-tree. In this regard, in order to estimate the execution of the proposed algorithm, the SSUP-tree algorithm has been implemented on synthetic and real datasets. The results of this study revealed that SSUP-tree shows a significant enhancement in the execution in terms of runtime since it keeps the huge databases details in a compact format and it avoids repetition of database scanning.
Construction and Application of an Online Child Portfolio Assessment System
Authors: Liu Jingrong , Liu Miao
Published: August 2019

Portfolio assessment is a comprehensive evaluation method for children’s development, and effective evaluation is based on professional children’s growth portfolios. The children’s growth portfolio mainly includes paper, electronic, and online forms, each with its own pros and cons. The online portfolios can avoid defects of paper portfolios, with large capacity, diversified evaluation body, flexible and customized design, professional leading significance, more integration and commemorative features. We have designed and implemented the “Ning Xiner Growth Records” online portfolio, which has been tested in several kindergartens, and achieved remarkable results. With continuous innovation of information technologies, the online portfolio will have broader development and application prospects. It is suggested that governments at all levels allocate special funds to support kindergartens to carry out online portfolio evaluation, develop targeted information technology training for teachers, and increase professional training and guidance for teachers in order to use Portfolio assessment effectively.
An Ensemble Learning Imbalanced Data Classification Method Based on Sample Combination Optimization
Authors: Wang Yuxin
Published: August 2019

Imbalanced data classification is one of the hot topics in data mining and machine learning in recent years. In practice, Imbalanced data classification is very common, such as cancer detection, spam discrimination, credit card fraud detection, etc. Because of the large difference in the number of categories and Imbalanced distribution, traditional classification algorithms have poor classification effect on minority classes, and correct identification of minority classes often brings greater value. Therefore, how to effectively identify minority classes in Imbalanced data is of great importance. Practical significance. Aiming at the problems that the Bagging-based Imbalanced data classification method cannot guarantee the validity and existence of classification boundaries by adding redundant noise information and sampling, an ensemble learning GABagging method based on sample combination optimization is proposed. Firstly, the sample combination optimization algorithm uses genetic algorithm to select a subset from most classes and construct a new data set with a few classes. Subsequently, several sample combinatorial optimization algorithms are used to train and integrate several classifiers. The experimental results show that GABagging can improve the correct recognition ability of minority classes on 19 Imbalanced datasets compared with other similar methods such as TPR and AUC, without excessive loss of recognition ability of majority classes. It is proved that GABagging can compensate for the shortcomings of related Bagging-based methods such as easy loss, increasing samples and not guaranteeing the validity and existence of classification boundaries after sampling.
Research on Routing Algorithm Based on Reinforcement Learning in SDN
Authors: Fang Chuntao , Cheng Cheng , Tang Zhongyun , Li Chuanhuang
Published: August 2019

Reinforcement learning is an unsupervised learning method which has been used in many fields. Actually, the essence of Reinforcement learning is a decision-making problem. It constantly tries to interact with the environment. Each interaction process will get a different feedback value, and then it adjusts each trial strategy through feedback. In this paper, we apply the Reinforcement learning technology to software defined network routing algorithm, and propose the routing algorithm based on Q-learning. Through the combination of Reinforcement learning and neural network, which means the Q-table in Q-learning is replaced by neural network, we present routing algorithm based on Deep Q-learning.
Analysis of Desired Receive Signal Impact in Wireless Co-time Co-frequency Full Duplex
Authors: Zhou Juan , Chen Chao , Xue Yajuan , Shen Ying , He Meng
Published: August 2019

With self-interference cancellation (SIC), a wireless full duplex terminal is allowed to transmit and receive signal simultaneously in the same frequency band. This paper focuses on the analysis of desired receive signal impact on the radio frequency (RF) SIC performance. The full-duplex system model is rst given, and the principle of radio frequency self-interference cancellation is introduced. Then, from the perspective of the convex function, the in uence of the desired signal on the RF SIC is analyzed when the total power of the signal after RF SIC is taken as the objective function. It is found that when there is no desired signal, the objective function is a convex function, and the residual self-interference power can converge to the minimum value by the gradient descent method. If the desired signal exists and the channel is constant, the objective function is also a convex function, and the residual self-interference power can also converge to the minimum value. However, in the presence of the desired signal and the channel uctuates, the target is not a convex function, and the residual self-interference power cannot be converged to the minimum value by the gradient descent method.
White Light Transmitting Antenna for Four-spectrum Mobile WDM-VLC
Authors: He Donglei , Tang Yi , Chang Yuee , Li Pingan
Published: August 2019

In this paper, we propose a mixing white light antenna with a homogenizer and an amplification system, and demonstrated its utilization in a four-spectrum mobile VLC. The central element is the homogenizer, which is a square integrating rod that mixes four-spectrum light into white light. Behind it, there are two Fresnel lenses to amplify the light-mixing area. The system is compact with a length of 80 mm and maximal diameter of 58.5 mm. We determined the initial structural parameters of the antenna by theoretical analysis, and then we determine the best parameters by simulation. Simulation results indicate that a 0.75 m×0.75 m area can be illuminated at 1.7 m distance. The detection surface has a high uniformity (76.27%), which can meet illumination and mobile communication requirements simultaneously.
Wireless Sensor Network Deployment Optimization Using Reference-Point-Based Non-dominated Sorting Approach (NSGA-III)
Authors: Metiaf Ali , Wu Qianhong
Published: August 2019

Wireless sensor networks (WSN) nowadays have gained more interest, pushed by the growing necessity for data collection and transmission from both civilian and military domains. WSN is constructed from interconnected sensors and limited resource (battery), which requests great importance on the deployment strategy to increase the performance metrics for WSN (lifetime, coverage, QoS connectivity). Also, the deployment is considered as a fundamental issue in (WSNs) design, and it was taken from the perspective of the multi-objective optimization problem. Many of the existing deployment strategies are based on metaheuristics algorithms such as Genetic Algorithms (GAs) to resolve the deployment problem. In this article, we use and adopt one of the most attractive approaches for wireless sensor networks deployment (WSND) optimization based on metaheuristic searching which is named Non-dominated Sorting Genetic Algorithm-III (NSGA-III) In order to reach maximum coverage and minimize the consumption of energy to maximize the network lifetime under the connectivity constraint. The comparison results have proved the NSGA-III algorithm outperformed the Constrained Pareto-based Multi-objective Evolutionary Approach (CPMEA) that taken as a benchmark for this study. Those results encourage the application of NSGA-III to real-world deployment problems, and the importance of this approach is that it can be handled many objectives.