bluuebunny/crossref_metadata_2025 huggingface dataset:
Spectral analysis‐based fault diagnosis algorithm for 3‐phase passive rectifiers in renewable energy systems
Authors: Sharan Bindu , Jain Tushar
Published: October 2020

Three‐phase passive (or uncontrolled) rectifiers are typically placed at the front end of the overall power conditioning circuit for AC to DC conversion in low‐cost, small‐scale renewable‐energy systems, e.g. residential purposes wind turbines. Whenever a diode in one leg or multiple legs becomes faulty, offering an open circuit to the flow of current in both directions, it severely affects the power quality at the grid‐side and may lead to the permanent disconnection of the power contributing unit from the grid. Even under a normal voltage rectification mode, an unbalance fault on the generator side may cause similar behaviour. To address these issues, this study presents a novel spectral analysis based fault detection and diagnosis (FDD) method for unbalance and open‐circuited faults in the 3‐phase uncontrolled rectifier. The proposed FDD algorithm accurately identifies the fault location based on magnitude and phase angles of different harmonic components of the filtered rectified voltage and specifically devised thresholds. The effectiveness of the proposed FDD algorithm is demonstrated through exhaustive MATLAB simulations of the grid‐connected power conditioning unit with variable 3‐phase supply. Subsequently, the hardware implementation of the overall experiment is demonstrated under a fixed voltage, and a fixed frequency source fed 3‐phase uncontrolled rectifier.
Hybrid IPT system with natural CC–CV output characteristics for EVs battery charging applications
Authors: Li Guanxi , Ma Hao
Published: October 2020

To charge the battery of electric vehicles (EVs), inductive power transfer (IPT) system has been considered to be more appropriate than traditional plug‐in system especially for its security and convenience. This study proposes a hybrid IPT system for EVs charging applications adopting one transmitter coil with series compensation and two receiver coils with series compensation and LCL compensation. With the help of the two receiver coils and proper parameters design, the proposed system can naturally obtain constant current (CC) and constant voltage (CV) outputs and the maximum output power can be naturally limited which can prevent the system from possible overload. Therefore, the reliability of the proposed system is increased. Since the mode switching process can be automatically realised according to the value of battery equivalent load without extra control strategy and circuit, the fixed‐frequency control can be used. Therefore, not only zero phase angle condition, but also the soft switching can be achieved. The theoretical analysis is presented with the design process of the IPT coils and resonance parameters for required battery charging profile. The performance of the system is verified by a 3.3 kW experimental prototype. The experimental results coincide well with the theoretical analysis.
Novel aluminium/polyvinylidene fluoride metastable intermolecular composite film prepared by solution casting method
Authors: He Pengfei , Wang Yajun , Li Shihui , Wan Yi
Published: October 2020

One challenge in the application of traditional metastable intermolecular composite (MIC) material is that MIC particles are not compatible with micro‐electro‐mechanical system. In the authors’ work, a solution casting method was employed to prepare aluminium/polyvinylidene fluoride (Al/PVDF) MIC films. The morphological, structural and compositional information of the samples were characterised by scanning electron microscopy, X‐ray diffraction, energy dispersive spectroscopy and Fourier transform infrared spectroscopy. The energy‐release characteristics of Al/PVDF films were studied by thermogravimetric analysis and differential scanning calorimetry. The results show that heat output and mass loss increased as the thickness of MIC films reduced. The maximum heat release of the main exothermic peak was 1032 J/g. The kinetics process could be divided into three stages with apparent activation energy calculated by Kissinger and Starink methods of 128.86, 164.69 and 153.16 kJ/mol, respectively.
Resistive switching in FTO/CuO–Cu2O/Au memory devices
Authors: Shariffar Amir , Salman Haider , Siddique Tanveer A. , Gebril Wafaa , Manasreh Mahmoud Omar
Published: October 2020

Memristors are considered to be next‐generation non‐volatile memory devices owing to their fast switching and low power consumption. Metal oxide memristors have been extensively investigated and reported to be promising devices, although they still suffer from poor stability and laborious fabrication process. Herein, the authors report a stable and power‐efficient memristor with novel heterogeneous electrodes structure and facile fabrication based on cupric oxide (CuO)–cuprous oxide (Cu2O) complex thin films. The proposed structure of the memristor contains an active complex layer of CuO and Cu2O sandwiched between fluorine‐doped tin oxide (FTO) and gold (Au) electrodes. The fabricated memristors demonstrate bipolar resistive switching (RS) behaviour with a low working voltage (∼1 V), efficient power consumption, and high endurance over 100 switching cycles. The authors suggest the RS mechanism of the proposed device is related to the formation and rupture of conducting filaments inside the memristor. Moreover, they analyse the conduction mechanism and electron transport in the active layer of the device during the RS process. Such a facile fabricated device has a promising potential for future memristive applications.
Effect of mantle oxidation state and escape upon the evolution of Earth’s magma ocean atmosphere
Authors: Katyal Nisha , Ortenzi Gianluigi , Lee Grenfell John , Noack Lena , Sohl Frank , Godolt Mareike , García Muñoz Antonio , Schreier Franz , Wunderlich Fabian , Rauer Heike
Published: October 2020

Context. The magma ocean period was a critical phase determining how Earth’s atmosphere developed into habitability. However, there are major uncertainties in the role of key processes such as outgassing from the planetary interior and escape of species to space that play a major role in determining the atmosphere of early Earth.

Aims. We investigate the effect of outgassing of various species and escape of H2 for different mantle redox states upon the composition and evolution of the atmosphere for the magma ocean period.

Methods. We included an important new atmosphere-interior coupling mechanism: the redox evolution of the mantle, which strongly affects the outgassing of species. We simulated the volatile outgassing and chemical speciation at the surface for various redox states of the mantle by employing a C-H-O based chemical speciation model combined with an interior outgassing model. We then applied a line-by-line radiative transfer model to study the remote appearance of the planet in terms of the infrared emission and transmission. Finally, we used a parameterized diffusion-limited and XUV energy-driven atmospheric escape model to calculate the loss of H2 to space.

Results. We have simulated the thermal emission and transmission spectra for reduced and oxidized atmospheres present during the magma ocean period of Earth. Reduced/thin atmospheres consisting of H2 in abundance emit more radiation to space and have a larger effective height than oxidized/thick atmospheres, which are abundant in H2O and CO2. We obtain that the outgassing rates of H2 from the mantle into the atmosphere are a factor of ten times higher than the rates of diffusion-limited escape to space. We estimate the timescale of total mass loss of outgassed H2 via escape to be few tens of million years, which is comparable to other studies.

Conclusions. Our work presents useful insight into the development of the terrestrial atmosphere during the magma ocean period and provides input to guide future studies that discuss exoplanetary interior compositions and their possible links with atmospheric compositions that might be estimated from observed infrared spectra by future missions.
On the problem of nightshade vegetables harvesting in conditions of limited land use and protected ground
Authors: Belousov Sergey V. , Onikienko Sergey Yu. , Klinova Darya M.
Published: October 2020

The paper is devoted to the analytical justification of nightshade vegetables harvesting in conditions of limited land use and protected ground, both by direct and reusable methods. The article has an analytical research character, which is expressed in the fact that the analysis of the method of nightshade vegetables harvesting is given. The main trend of technology development and improvement of its design to advance the quality parameters of harvesting is identified. As a result of the work done, the conclusion is made about the importance of nightshade vegetables harvesting and in the development of new varieties in the context of modern approaches to the cultivation of nightshade vegetables.
Justification of design parameters of a disk working body with a changing radius of curvature
Authors: Konovalov Vladimir I.
Published: October 2020

In recent years, the improvement of the technological process of soil treatment is based on the use of working bodies with a curved shape of the working surface, which can increase the agro-technical and reduce the energy-intensive parameters of soil treatment. Agricultural units with disk working bodies are one of the most common machines in agriculture. The article presents a design scheme of a disk working organ with a working surface made along the Archimedes ’ spiral. Expressions are obtained for designing the working surface of the disk with the specified initial parameters.
Development and substantiation of main design portable operating table parameters for small animals
Authors: Kotov Dmitrii , Nenashev Igor , Vdovkin Sergei , Kryuchin Nikolai
Published: October 2020

The article substantiates the need of development of a portable operating table designed for performing medical manipulations, both in and out veterinary clinics. On the basis of the analysis of existing veterinary operating tables, the design of the portable operating table is proposed the parameters of the main elements are justified by theoretical calculations. The use of the portable operating table due to improvements of its ergonomic characteristics allows reducing the amount of time and improving the quality of operations.
Device for robotic picking of strawberries
Authors: Khort D. O. , Kutyrev A. I. , Filippov R. A. , Vershinin R. V.
Published: October 2020

The article presents a device for collecting strawberry berries, presents a 3D model of an automated manipulator with a computer vision system. The overall dimensions of the manipulator (WxDxH), mm - 200x700x600, the number of degrees of freedom - 6, load capacity - 1 kg, the maximum effort to detach fruits and berries - 10-80 N. An algorithm for the operation of a computer vision system for determining the boundaries of berries and their ripeness based on size factor. The results of field experiments, measuring the area of berries of wild strawberries at different times of the day are given. It was established that the lighting conditions have a significant effect on the detection of the boundaries and area of garden strawberries, and their ripeness.
Technical support in seed production of agricultural plants
Authors: Litvinov M.A. , Adamyan A.A. , Dat Hoang Ngnia
Published: October 2020

Now days automatization of agriculture is perspective and actively developing branch of researches. On this moment there are many international researches which offers ready made solutions for automatic control of sowing agricultures crops. However Most part of sowing are made on a mechanization devices with obligatory control of high qualified service employees in Russia. In this case, it was proposed to automatization of the process of sowing seeds.
Influence of intensity of illumination on weed recognition algorithm
Authors: Mirzaev M. A. , Dyshekov A.I. , Smirnov I.G.
Published: October 2020

This study explores the influence of daylight illumination on operating of autonomous robotic weed control complex. The illumination value is taken from minimum on the order of a few lux (high overcast) to maximum exceeding one hundred twenty thousand lux (bright noon). This was done to cover the entire daylight illumination range. This experiment is not focused on operating of the algorithm using the artificial light sources since they are supposed to be easily adjusted with the proper equipment. The performance of the algorithm at various illumination levels is evaluated by the surface area of the recognized beet crops on early stages of growth.
Pesticide monitoring of agricultural soil pollution
Authors: Zhichkina Lyudmila , Nosov Vladimir , Zhichkin Kirill , Zhenzhebir Vyacheslav , Abramov Yury , Alborova Mira
Published: October 2020

The role of pesticides in modern agriculture is not in doubt; the continuous improvement of drugs and technologies for their use reduces the possibility of environmental pollution and their accumulation in manufactured products. The purpose of the research is to assess the pollution of the soil cover of agricultural land with residual amounts of pesticides in the Samara region conditions. Tasks: to analyze the content of insectoacaricides and herbicides residual amounts in the soil in the spring and autumn; - establish patterns of residual pesticides migration along the soil profile. As a result of studies conducted in 2016-2018. it was found that the content of total DDT related to the first hazard class in the studied samples decreases, a similar situation is observed for organochlorine insectoacaricides HCH and HCB, their residual amounts were found in the soil in the autumn and spring periods of 2016. Residual quantities of the organophosphorus insect metacosacaricide were detected annually (the exception was the autumn period of 2017). Regarding the content of residual amounts of herbicides in the soil (2, 4-D, dalapon, simazine, atrazine, promethrin, trifluralin, THAN), it can be noted that during the years of research their content was mainly reduced. A study of the pesticides vertical migration showed that the content of their residual amounts in the soil increases with depth, reaching a maximum at a depth of 1.0-1.6 m.
Hydrothermal treatment of sunflower seeds in grain washing machines with spiral screw devices
Authors: Gafin Munir
Published: October 2020

The presented article examines the relevance of the process of preparing sunflower seeds before roasting for the production of snacks by washing as one of the ways to increase the efficiency of this type of production. The article also gives a brief overview of the advantages of washing and the disadvantages of this method of preparing seeds for roasting, and highlights possible ways of leveling the negative consequences of moistening-washing.
Improving the use of wood waste
Authors: Ilyushenko D.A. , Markov V.A. , Sokolova V.A. , Kalyashov V.A.
Published: October 2020

On the territory of our country, including St. Petersburg and the Leningrad Region, there are a large number of enterprises engaged in the processing of wood for various purposes, among which, to a large extent, there are enterprises involved in the primary processing of wood in sawmills. The resulting wood waste from bark and sawdust, in most enterprises, lead to rotting processes. The issue of the utilization of these wastes in practice can increase the production culture, increase the amount of recyclable waste from a timber processing enterprise and, thus, increase its efficiency. The article describes a mathematical model for the dynamic compaction of ground wood bark with the aim of producing fuel briquettes of their debarking waste.
Improving the environmental culture of employees at the enterprise, based on the environmental management system and sustainable development principles
Authors: Ostapenko Maria , Kholboeva Umida
Published: October 2020

Culture is an integral part of human formation, and environmental culture determines a person’s willingness to make environmentally friendly decisions in all areas of activity. It is the level of ecological culture that determines the practical readiness to responsibly treat the environment of both employees and managers. To this end, this article explores the problem of an insufficient level of ecological culture development of employees and managers of enterprises that entail a deterioration in the environment quality. When studying this topic, special attention has been paid to the implementation of an environmental management system based on the sustainable development principles. The methods to increase the interest of managers in the introduction and implementation of the environmental management system, based on the European Union experience, and ways to improve the environmental culture of employees in the enterprise are analyzed. The result of the study is practical and theoretical methods for improving environmental culture, based on early scientific research in this area and personal opinions of the authors.
Quantification of model uncertainty on path-spaceviagoal-oriented relative entropy
Authors: Birrell Jeremiah , Katsoulakis Markos A. , Rey-Bellet Luc
Published: October 2020

Quantifying the impact of parametric and model-form uncertainty on the predictions of stochastic models is a key challenge in many applications. Previous work has shown that the relative entropy rate is an effective tool for deriving path-space uncertainty quantification (UQ) bounds on ergodic averages. In this work we identify appropriate information-theoretic objects for a wider range of quantities of interest on path-space, such as hitting times and exponentially discounted observables, and develop the corresponding UQ bounds. In addition, our method yields tighter UQ bounds, even in cases where previous relative-entropy-based methods also apply,e.g., for ergodic averages. We illustrate these results with examples from option pricing, non-reversible diffusion processes, stochastic control, semi-Markov queueing models, and expectations and distributions of hitting times.
Well-posedness and numerical approximation of a fractional diffusion equation with a nonlinear variable order
Authors: Li Buyang , Wang Hong , Wang Jilu
Published: October 2020

We prove well-posedness and regularity of solutions to a fractional diffusion porous media equation with a variable fractional order that may depend on the unknown solution. We present a linearly implicit time-stepping method to linearize and discretize the equation in time, and present rigorous analysis for the convergence of numerical solutions based on proved regularity results.
Cell salvage within adult and pediatric idiopathic scoliosis surgery: A random cross-sectional study
Authors: Al-Mohrej Omar A. , Al-Torbaq Bayan , Hshem Raed , Sayer Jason , Al-Rabiah Anwar M. , Al-Zayed Zayed S.
Published: October 2020

Introduction: This study aimed to evaluate the use of a cell savage and its impact on the amount of allogenic blood transfused to the patients during idiopathic scoliosis surgery. Methods: A total of 142 randomly selected patients with scoliosis had been included in this study. The adult group consisted of 78 patients, and the pediatric group, 64 patients. Both groups were divided into subgroups (pre-cell saver era and cell saver era). Data on the following parameters were collected: amount of blood transfused intraoperatively, within 24 h postoperatively, and overall. The number of patients who received transfusion was counted as the number of patients who avoided any transfusion. For statistical purposes, we performed unpaired student t-test, chi-square test, and Mann–Whitney test. Results: There was no significant difference in adult groups perioperatively. In the pediatric group, there was a statistically significant difference intraoperatively. Economic analysis of blood management showed positive numbers for both groups, where more than 1 unit of blood was transfused. Conclusions: Statistical analysis showed the cost-effectiveness of the perioperative use of cell salvage during pediatric scoliosis surgery. Overall, the use of cell salvage during scoliosis surgery had a positive impact on both blood management and patient recovery.
Artificial Intelligence in Small Bowel Endoscopy: Current Perspectives and Future Directions
Authors: Meher Dinesh , Gogoi Mrinal , Bharali Pankaj , Anirvan Prajna , Singh Shivaram Prasad
Published: October 2020

Artificial intelligence (AI) is a computer system that is able to perform tasks which normally require human intelligence. The role of AI in the field of gastroenterology has been gradually evolving since its inception in the 1950s. Discovery of wireless capsule endoscopy (WCE) and balloon enteroscopy (BE) has revolutionized small gut imaging. While WCE is a relatively patient-friendly and noninvasive mode to examine the nonobstructed small gut, it is limited by a lengthy examination time and the need for expertise in reading images acquired by the capsule. Similarly, BE, despite having the advantage of therapeutic intervention, is costly, invasive, and requires general sedation. Incorporation of concepts like machine learning and deep learning has been used to handle large amounts of data and images in gastroenterology. Interestingly, in small gut imaging, the application of AI has been limited to WCE only. This review was planned to examine and summarize available published data on various AI-based approaches applied to small bowel disease.

We conducted an extensive literature search using Google search engine, Google Scholar, and PubMed database for published literature in English on the application of different AI techniques in small bowel endoscopy, and have summarized the outcome and benefits of these applications of AI in small bowel endoscopy. Incorporation of AI in WCE has resulted in significant advancements in the detection of various lesions starting from dysplastic mucosa, inflammatory and nonmalignant lesions to the detection of bleeding with increasing accuracy and has shortened the lengthy review time in image analysis. As most of the studies to evaluate AI are retrospective, the presence of inherent selection bias cannot be excluded. Besides, the interpretability (black-box nature) of AI models remains a cause for concern. Finally, issues related to medical ethics and AI need to be judiciously addressed to enable its seamless use in future.
Beyond the Tip of the Blade: An Investigation of Upper Extremity Machete Injuries in Honduras
Authors: Johnson Anna Rose , Laínez Stephanie S. , Santos Herman J. , Chen Austin D. , Laínez Carlos , Lin Samuel J. , Agag Richard L. , Lee Bernard T.
Published: October 2020

Background Machete injuries constitute a major cause of morbidity in Honduras. In this study, we aimed to determine the incidence, initial management, surgical treatment, and follow-up patterns for machete injuries at the national public hospital in Honduras. Microsurgery in Honduras is currently in transition with limitations at multiple levels. This study aims to provide critical information to better prepare visiting surgeons and establishes a blueprint to improve microsurgical reconstruction.

Methods A retrospective chart review was performed to identify patients with machete injuries to the upper extremity (UE) who presented to the Hospital Escuela Universitario (HEU) for treatment from 2015 to 2017. Additional microsurgical data was obtained by personal communication with members of the plastic surgery department at the HEU.

Results Complete data was retrieved for 100 patients who presented to the HEU with a UE machete wound. The cohort was male dominated (93%), employed as farmers (47%), and had a mean age of 32.1 years. Violence was the most common mechanism of injury (p < 0.001). The majority of UE machete injuries involved tendon (70%), nerve (28%), and an open fracture (55%). Of the 76% of patients who were scheduled for a follow-up visit, only 25% attended. Within the last calendar year, one replantation, 10 revascularizations at the wrist and forearm level, three microvascular free tissue transfers, and 175 nerve repairs were performed.

Conclusion Management of UE machete injuries in Honduras is challenging and requires early recognition of possible injuries to multiple anatomical systems. The majority of injuries required operative intervention. Only a small percentage of patients presented for follow up. A program to streamline care starting at injury recognition up to final follow-up is currently unavailable and needs to be developed to optimize microsurgical care.
Poverty and precarious employment: the case of Rohingya refugee construction workers in Peninsular Malaysia
Authors: Nungsari Melati , Flanders Sam , Chuah Hui-Yin
Published: October 2020

How do refugees economically cope in host countries where they have no legal right to work? Most Southeast Asian countries have not ratified the 1951 United Nations Refugee Convention. This implies that many refugees in this region do not enjoy any protection from the law, do not possess the legal right to work, and often resort to participation in dirty, dangerous, and demeaning jobs in order to make ends meet. In this paper, we study Rohingya refugees working as construction workers in the informal economy in Peninsular Malaysia by employing a mixed methods methodology. Specifically, we utilize micro-level survey data collected from a representative population of 314 Rohingya refugee workers in the construction industry, as well as in-depth interviews conducted with a subset of 77 of the survey respondents. Using the survey data, we first provide an overview of the social and economic lives of our respondents by summarizing key variables such as demographics, integration measures, and healthcare access. We then utilize regression analysis to understand the relationships between these variables. The key quantitative finding is that Rohingya refugees in the construction industry earn significantly above minimum wage in Malaysia (albeit less than their legal counterparts), and significantly more than their earnings prior to arriving in Malaysia. This is true even after adjusting for purchasing power. We then conduct a thematic analysis on the qualitative data obtained through the interviews to understand the dimensions of employment for the respondents. We find that although the construction industry in Peninsular Malaysia has provided Rohingya refugees with the means to escape poverty, they still face a tremendous amount of precarity and uncertainty in their lives.
Moments of the logarithmic derivative of characteristic polynomials from SO(N) and USp(2N)
Authors: Alvarez E. , Snaith N. C.
Published: October 2020

We study moments of the logarithmic derivative of characteristic polynomials of orthogonal and symplectic random matrices. In particular, we compute the asymptotics for large matrix size, N, of these moments evaluated at points that are approaching 1. This follows the work of Bailey et al. [J. Math. Phys. 60(8), 083509 (2019)] where they computed these asymptotics in the case of unitary random matrices.
Specific absorption rate of magnetic nanoparticles: Nonlinear AC susceptibility
Authors: Déjardin J.-L. , Vernay F. , Kachkachi H.
Published: October 2020

In the context of magnetic hyperthermia, several physical parameters are used to optimize the heat generation, and these include the nanoparticles concentration and the magnitude and frequency of the external AC magnetic field. Here, we extend our previous work by computing nonlinear contributions to the specific absorption rate, while taking into account (weak) inter-particle dipolar interactions and a DC magnetic field. In the previous work, the latter were shown to enhance the specific absorption rate in some specific geometries and setup. We find that the cubic correction to the AC susceptibility does not modify the qualitative behavior observed earlier but does bring a non-negligible quantitative change of specific absorption rate, especially at relatively high AC field intensities. Incidentally, within our approach based on the AC susceptibility, we revisit the physiological empirical criterion on the upper limit of the product of the AC magnetic field intensity H0 and its frequency f and provide a physicist’s rationale for it.
Double core shell structured Al@Al2O3@SiO2 filled epoxy composites for thermal management application
Authors: Xu Xinwei , Niu Yujuan , Yao Bin , Dong Jiufeng , Hu Renchao , Wang Hong
Published: October 2020

Polymer composites are preferred as thermal conductive interface materials because of their light weight, low cost, and ease of processing. However, polymers are subjected to low thermal conductivity. The enhancement of their thermal conductivity is often at the cost of deteriorating dielectric properties, resulting in a substantial increase in the dielectric constant, dielectric loss, and conductivity. In order to address this problem, we developed a double core shell structured Al@Al2O3@SiO2 filled epoxy composite to enhance the thermal conductivity as well as keep the low dielectric constant and dielectric loss. The thermal conductivity of the composite with a loading of 40 wt. % fillers can be enhanced by three times that of the pure epoxy. Compared with the composite loaded with the unmodified aluminum particles, the double core shell Al@Al2O3@SiO2 is more effective in curbing the trend of the steep rise of the dielectric constant, dielectric loss, and conductivity of the composites. The potential use of the obtained composites for the thermal management of power light emitting diodes (LEDs) and chips has also been demonstrated by a practical LED chip and the analysis of finite element simulation.
High-Q, directional and self-assembled random laser emission using spatially localized feedback via cracks
Authors: Dogru-Yuksel Itir Bakis , Han Mertcan , Pirnat Gregor , Magden Emir Salih , Senses Erkan , Humar Matjaž , Nizamoglu Sedat
Published: October 2020

Lasers based on Fabry–Pérot or whispering gallery resonators generally require complex fabrication stages and sensitive alignment of cavity configurations. The structural defects on reflective surfaces result in scattering and induce optical losses that can be detrimental to laser performance. On the other hand, random lasers can be simply obtained by forming disordered gain media and scatterers, but they generally show omnidirectional emission with a low Q-factor. Here, we demonstrate directional random lasers with a high Q-factor emission (∼1.5 × 104) via self-assembled microstructural cracks that are spontaneously formed upon radial strain-release of colloidal nanoparticles from the wet to dry phase. The rough sidewalls of cracks facilitate light oscillation via diffuse reflection that forms a spatially localized feedback, and they also serve as the laser out-coupler. These self-assembled cracks exhibit random lasing at optical pump powers as low as tens of μJ/mm2. We demonstrate a wide variety of random lasers from nano- and biomaterials including silica nanoparticles, fluorescent proteins, and biopolymers. These findings pave the way toward self-assembled, configurable, and scalable random lasers for sensing, displays, and communication applications.
Fractional variational principle of Herglotz for a new class of problems with dependence on the boundaries and a real parameter
Authors: Almeida Ricardo , Martins Natália
Published: October 2020

The fractional variational problem of Herglotz type for the case where the Lagrangian depends on generalized fractional derivatives, the free endpoints conditions, and a real parameter is studied. This type of problem generalizes several problems recently studied in the literature. Moreover, it allows us to unify conservative and non-conservative dynamical processes in the same model. The dependence of the Lagrangian with respect to the boundaries and a free parameter is effective and transforms the standard Herglotz’s variational problem into a problem of a different nature.
Direct numerical simulation on the effects of surface slope and skewness on rough-wall turbulence
Authors: Kuwata Y. , Nagura R.
Published: October 2020

This paper presents direct numerical simulation results of turbulent flows over systematically varied rough surfaces. Three-dimensional irregular rough surfaces with varying effective slope and skewness factor and fixed roughness height scales were considered in the study. The skewness factor characterizes whether the surface of interest has a peak-dominated or valley-dominated nature, whereas the effective slope measures the wavelength of the surface undulations or solidity of the roughness elements. The influence of these two topological parameters on the friction drag at rough surfaces was investigated. Downward shifts in the inner-scaled mean velocity, which quantify an increase in the friction drag, were found to be larger for surfaces with a positive skewness factor, and this trend was found to be more pronounced as the effective slope increased. In addition, the downward shift value steeply increased with increases in the effective slope, while the dependence weakened when the effective slope was larger than a certain threshold value. The physical mechanism behind the increase in the roughness function was investigated by analyzing the momentum budgets. It was revealed that the viscous drag dominantly contributes to the roughness function when the effective slope value is small, whereas the contribution by the pressure drag progressively increases with the effective slope. We also found that for surfaces with larger effective slope consisting of relatively shorter wavelength undulations, the Reynolds shear stress tends to be reduced because the wall roughness prevents the formation of quasi-streamwise elongated vortices suppressing the turbulent near-wall cycles. This acts as a negative contribution to the roughness function, and the two competing effects (of the increase in pressure drag and decrease in Reynolds shear stress) weaken the dependence of the effective slope value on the roughness function. Further analysis was conducted to better understand how the surface slope and skewness factor values affect the mean flow field, modifying the pressure and viscous drag forces.
Diagnostics of CO concentration in gaseous mixtures at elevated pressures by resonance enhanced multi-photon ionization and microwave scattering
Authors: Sharma Animesh , Braun Erik L. , Patel Adam R. , Arafat Rahman K. , Slipchenko Mikhail N. , Shneider Mikhail N. , Shashurin Alexey
Published: October 2020

In this work, a novel diagnostic technique for carbon monoxide (CO) number density measurements in a nitrogen buffer mixture at elevated pressures up to 5 bar was developed and tested. The technique utilizes 2 + 1 resonance enhanced multi-photon ionization (REMPI) of CO induced by a femtosecond laser pulse at 230.1 nm, followed by detection of the number of REMPI-induced electrons using the microwave scattering (MS) method (REMPI-MS technique). Dependences of the number of REMPI-generated electrons on CO number density and laser energy were measured and analyzed in conjunction with a four energy level model of the CO molecule. The number of REMPI-induced electrons scaled linearly with CO number density up to about 5 × 1018 cm−3 and was independent of the buffer gas pressure up to 5 bar. Higher CO number densities caused saturation onset associated with laser beam energy loss while travelling through the gaseous mixture due to two-photon absorption and photoionization. The number of REMPI-induced electrons was found to scale cubically with the laser pulse energy for the tested energy range of 8–20 μJ (intensity in the focal region about 7–18 GW/cm2), which is consistent with the operation regime where the number density of excited CO molecules increases throughout the laser pulse duration and does not saturate in time. The linear scaling region of the REMPI-MS signal can be used for a CO number density diagnostic after appropriate calibration of the system.
Perceptions of allied health staff of the implementation of an integrated electronic medical record across regional and metropolitan settings
Authors: Schwarz Maria , Coccetti Anne , Draheim Michael , Gordon Gail
Published: October 2020

ObjectiveThe aim of this study was to investigate the perceptions of allied health professionals (AHPs) to implementation of an integrated electronic medical record (EMR) across both regional and metropolitan settings.
MethodsThe study was conducted as a cross-sectional electronic survey. AHPs working at three hospital sites within Queensland Health were sent an electronic survey link. Participation was voluntary and recruitment via a snowball sampling technique was encouraged. Responses were analysed descriptively.
ResultsIn all, 104 responders completed the survey. Responders were distributed across three sites within the selected health service, with most (75%; n=78) being at the largest site. Physiotherapy accounted for the largest number of responders (22%). Most responders were female (87%; n=90) and between 20 and 40 years of age (68%; n=71). On a scale from 0 (being anxious) to 100 (being excited), at the time EMR implementation was announced, there was a trend towards excitement (mean score 59). The most commonly reported factor hindering EMR implementation was the opportunity to practice with EMR (34%), whereas clinical ‘change champions’ were reported as the most common facilitators (61%). Overall, 60% of responders were very satisfied or satisfied with the EMR, but limited effects on efficiency and patient care were reported.
ConclusionsThe results suggest an overall positive response to EMR implementation. Minimal staff reported effects such as stress or anxiety in the workplace related to EMR implementation, and a perception of ‘comfort’ was cited once EMR was part of usual practice. However, responders did not report a significant effect on speed, efficiency or quality of patient care following EMR implementation.
What is known about the topic?A growing body of literature exists regarding the perceptions of staff (particularly medical officers) in moving towards EMRs, but there is limited evidence regarding the perceptions of AHPs, and the barriers and facilitators to this change.
What does this paper add?This paper presents a novel perspective regarding the perceptions of AHPs regarding the implementation of an EMR and provides a perspective of the barriers and facilitators that supported a smooth transition at three sites.
What are the implications for practitioners?Despite being a large-scale service change, the introduction of an EMR did not significantly increase AHPs’ subjective feelings of anxiety. Services considering EMR implementation should invest in the provision of timely information, ‘at-elbow’ support and opportunities to practice the new system.
Factors affecting procurement of wound care products: a qualitative study of hospital managers and clinicians
Authors: McInnes Elizabeth , Harvey Gill , Hiller Janet E. , Phillips Rosemary , Page Tamara , Wiechula Rick
Published: October 2020

ObjectiveTo identify factors that influence procurement and disinvestment decisions for wound care products in the acute care setting.
MethodsA qualitative descriptive study was undertaken. Eighteen face-to-face semi-structured interviews were conducted with purposively sampled senior clinical and non-clinical managers from three Australian acute care hospitals with responsibility for consumables procurement and disinvestment decisions. Data were coded and analysed thematically.
ResultsThree main themes (Systems and triggers, Evidence-free zone, Getting the governance right) with sub-themes were identified that reflect that: (1) procurement processes were often ad hoc and workarounds common. Disinvestment was poorly understood and opportunities were missed to reduce use of low value products ; (2) product selection was commonly based on clinician preference, contractual obligations and information from industry representatives; and (3) improved evidence-based governance and processes are needed to connect procurement and disinvestment decisions and to minimise the influences of clinician preference and industry representatives on product selection.
ConclusionsSystematic and evidence-based approaches are needed to strengthen procurement and disinvestment decisions related to consumables such as wound care products and to minimise the purchasing of low-value products Decision-making frameworks should consider cost and clinical effectiveness and enable the identification of opportunities to disinvest from low-value products.
What is known about the topic?High volume–low unit cost healthcare consumables such as wound care products are a major component of healthcare expenditure. Disinvestment from low-value wound care products has potential to improve patient outcomes and optimise health resources.
What does this paper add?Disinvestment was poorly understood and considered in isolation from procurement decisions. Procurement decisions were rarely informed by research evidence, with clinicians exercising considerable freedom to make purchasing decisions based on product preference and industry information. Frameworks and guidelines are needed to guide procurement and disinvestment decision-making for wound care products.
What are the implications for practitioners?New models for procurement and disinvestment decision-making for wound care products could help to strengthen decision-making processes, facilitate evidence-based product choices and also prompt consideration of removal of low-value products.
Benefits of human-animal interactions for mental health and well-being.
Authors: Hediger Karin , Beetz Andrea M.
Published: October 2020

This impact of animals on human health and well-being are described. This chapter begins by providing a short overview of the general known positive effects on human mental health and wellbeing from the contact with pets that are kept at home as companion animals, describes case examples of a companion animal providing social and emotional stability during a crisis and the important aspects of pet keeping for healthy aging. This is followed by the specific effects on human mental health from animals introduced into interventions to address human mental health problems based on recent studies. A case example is included regarding the importance of a One Health approach in this field by focusing on the two different sides of the partners involved: (i) the patient and (ii) the animal. Finally, the interconnectedness of human and animal well-being in animal-assisted interventions, human-pet relationships with lessons learned and gaps in application of the One Health framework for animal-assisted interventions are discussed.
Spike frequency–dependent inhibition and excitation of neural activity by high-frequency ultrasound
Authors: Prieto Martin Loynaz , Firouzi Kamyar , Khuri-Yakub Butrus T. , Madison Daniel V. , Maduke Merritt
Published: October 2020

Ultrasound can modulate action potential firing in vivo and in vitro, but the mechanistic basis of this phenomenon is not well understood. To address this problem, we used patch-clamp recording to quantify the effects of focused, high-frequency (43 MHz) ultrasound on evoked action potential firing in CA1 pyramidal neurons in acute rodent hippocampal brain slices. We find that ultrasound can either inhibit or potentiate firing in a spike frequency–dependent manner: at low (near-threshold) input currents and low firing frequencies, ultrasound inhibits firing, while at higher input currents and higher firing frequencies, ultrasound potentiates firing. The net result of these two competing effects is that ultrasound increases the threshold current for action potential firing, the slope of frequency-input curves, and the maximum firing frequency. In addition, ultrasound slightly hyperpolarizes the resting membrane potential, decreases action potential width, and increases the depth of the after-hyperpolarization. All of these results can be explained by the hypothesis that ultrasound activates a sustained potassium conductance. According to this hypothesis, increased outward potassium currents hyperpolarize the resting membrane potential and inhibit firing at near-threshold input currents but potentiate firing in response to higher-input currents by limiting inactivation of voltage-dependent sodium channels during the action potential. This latter effect is a consequence of faster action potential repolarization, which limits inactivation of voltage-dependent sodium channels, and deeper (more negative) after-hyperpolarization, which increases the rate of recovery from inactivation. Based on these results, we propose that ultrasound activates thermosensitive and mechanosensitive two-pore-domain potassium (K2P) channels through heating or mechanical effects of acoustic radiation force. Finite-element modeling of the effects of ultrasound on brain tissue suggests that the effects of ultrasound on firing frequency are caused by a small (<2°C) increase in temperature, with possible additional contributions from mechanical effects.
LDA+U study of hydrostatic pressure effect on double perovskite Sr2FeNbO6: crystal structure, mechanical and electronic properties
Authors: Rosas-Huerta J L , Antonio J E , Romero M , León-Flores J , Pilo J , Carvajal E , Escamilla R
Published: October 2020

To study the effect of the applied hydrostatic pressure on the crystal structure and the electronic and mechanical properties of the Sr2FeNbO6 compound, computational calculations in the density functional theory framework, with the local density approximation and Hubbard correction as it is treated by the CA-PZ exchange-correlation functional were performed. The tetragonal structure with the I4/m space group is reported stable in the range from zero to 50 GPa according to Born’s stability criterion. No crystal phase transition was found in agreement with experimental data; however, between 20 and 30 GPa, a brittle to ductile transition is confirmed by the Pugh’s criterion and Poisson’s ratio. Moreover, a change from ionic-covalent to metallic bonding is suggested by the Poisson’s ratio. This behavior is reflected in the electronic properties, through the controlled modulation of the energy bandgap (Eg (eV)) as a function of pressure, according to a fitted linear equation, Eg = (−0.016)P + 2.040. At 50 GPa, Eg value is 1.236 eV, very close to the ideal 1.34 eV, which is required for hydrogen generation and photovoltaic applications.
Selective excitation of vibrational states in three-state Na2 molecule by a chirped laser pulse
Authors: Chen Ya-Zhou , Wang Shuo
Published: October 2020

We have theoretically investigated the population transfer and the selective excitation of vibrational states of the target state in a three-state Na2 molecule using the chirped adiabatic passage. The population transfer among electronic states is studied. Compared with the single negative chirped pulse, complete population transfer can be achieved by using a positive chirped pulse. The effects of laser parameters on vibrational population distribution are discussed, and the selective excitation of vibrational states can be achieved by adjusting the central frequency. Finally, we give the method of selective excitation of specific vibrational states.