bluuebunny/crossref_metadata_2025 huggingface dataset:
Space–time decay of solutions to three-dimensional MHD equations with Hall and ion-slip effects
Authors: Zhao Xiaopeng
Published: June 2021

In this paper, we study the space–time decay rate of solutions to three-dimensional incompressible MHD equations with Hall and ion-slip effects in the whole space R3. Based on a parabolic interpolation inequality, bootstrap argument, and some weighted estimates, we obtain the higher order mixed spatial and time derivative estimates for such a system.
Voltage-control of damping constant in magnetic-insulator/topological-insulator bilayers
Authors: Chiba Takahiro , Leon Alejandro O. , Komine Takashi
Published: June 2021

The magnetic damping constant is a critical parameter for magnetization dynamics and the efficiency of memory devices and magnon transport. Therefore, its manipulation by electric fields is crucial in spintronics. Here, we theoretically demonstrate the voltage-control of magnetic damping in ferro- and ferrimagnetic-insulator (FI)/topological-insulator (TI) bilayers. Assuming a capacitor-like setup, we formulate an effective dissipation torque induced by spin-charge pumping at the FI/TI interface as a function of an applied voltage. By using realistic material parameters, we find that the effective damping for a FI with 10 nm thickness can be tuned by one order of magnitude under the voltage of 0.25 V. Also, we provide perspectives on the voltage-induced modulation of the magnon spin transport on proximity-coupled FIs.
Structural analysis and optimization design of mechanical pendulum of differential capacitance seismometer
Authors: Qiu Zhongchao , Zhang Bingbing , Zhang Tao , Teng Yuntian , Tang Yixiang
Published: June 2021

Seismometers can collect and record earthquake information in real time, and they play an important role in earthquake prediction and post-earthquake monitoring. Aiming at the high natural frequency problem of the mechanical pendulum of differential capacitance seismometers, this study employed the ANSYS simulation software to establish a finite element model of the mechanical pendulum; using the constructed model, this study performed static and modal analysis on the key structure, the cross reed, and conducted topological optimization on the shape of the reed. Moreover, the sine calibration method was adopted to measure the natural frequency of the mechanical pendulum before and after optimization, and the experimental results showed that after optimization, the natural frequency of the mechanical pendulum had been reduced by 22%, decreasing from 5.4 to 4.2 Hz, which proved the feasibility of the optimization design.
Shock-induced melting of two-dimensional Yukawa systems from TH−PH Hugoniot curves
Authors: Sun Tianyue , Feng Yan
Published: June 2021

The TH−PH Hugoniot curves of compressional shocks in 2D Yukawa systems are derived from the combination of the Rankine–Hugoniot relation around the shock front and the universal relationship for the temperature in the postshock region. From the equation of state of 2D Yukawa liquids, the equilibrium melting curve for 2D Yukawa systems is derived using the two variables of the temperature T and the pressure P. It is found that the obtained TH−PH Hugoniot curves are intercepted by the equilibrium melting curve, indicating the existence of shock-induced phase transition at these crossing points. To confirm this prediction, molecular dynamical simulations of 2D Yukawa systems of κ=0.75 for the conditions around the crossing point are performed. In the postshock region, the calculated various diagnostics of static structural measures, like the Voronoi diagram, the defect ratio, the probability distribution of the shape factors ξ, the pair correlation function g(r), and the static structure factor S(q), suggest that, for our studied system, the shock-induced melting happens when the compressional speed of the boundary is 0.212a0ωpd<vleft<0.283a0ωpd, the same as the prediction from the crossing point.
Dynamics of droplet migration in oscillatory and pulsating microchannel flows and prediction and uncertainty quantification of its lateral equilibrium position using multifidelity Gaussian processes
Authors: Lafzi Ali , Dabiri Sadegh
Published: June 2021

The dynamics of a droplet in oscillatory and pulsating flows of a Newtonian fluid in a microchannel has been studied numerically. The effects of oscillation frequency, surface tension, and channel flow rate have been explored by simulating the drop within a microchannel. These types of flows introduce new equilibrium positions for the drop compared to steady flows with similar conditions. The simulation results are very sensitive to the grid resolution due to the unsteady behavior of the base flow. Therefore, a set of fine grids have been used in this study to capture the physics of this problem more accurately. However, these fine grids make the computations significantly expensive. Therefore, a multifidelity Gaussian processes method with two levels of fidelity has been used to predict the results of the remaining fine-grid simulations along with their uncertainties based on their correlations with those of the coarse-grid cases over a wide range of input parameters.
Branching and phase corrected surface hopping: A benchmark of nonadiabatic dynamics in multilevel systems
Authors: Shao Cancan , Xu Jiabo , Wang Linjun
Published: June 2021

Since the seminal work of Tully [J. Chem. Phys. 93, 1061 (1990)], two-level scattering models have been extensively adopted as the standard benchmark systems to assess the performance of different trajectory surface hopping methods for nonadiabatic dynamics simulations. Here, we extend the branching and phase corrections to multilevel systems and combine them with both the traditional fewest switches surface hopping (FSSH) and its variant global flux surface hopping (GFSH) algorithms. To get a comprehensive evaluation of the proposed methods, we construct a series of more challenging and diverse three-level and four-level scattering models and use exact quantum solutions as references. Encouragingly, both FSSH and GFSH with the branching and phase corrections produce excellent and nearly identical results in all investigated systems, indicating that the new surface hopping methods are robust to describe multilevel problems and the reliability is insensitive to the definition of self-consistent hopping probabilities in the adiabatic representation. Furthermore, the branching correction is found to be especially important when dealing with strongly repulsive potential energy surfaces, which are common in realistic systems, thus promising for general applications.
When ancestry haunts – can evolutionary links to ancestors affect vulnerability of Australian prey to introduced predators? A preliminary study
Authors: Heise-Pavlov Sigrid , Bradley Adrian
Published: June 2021

The high extinction risk of Australian marsupials has been attributed to their failure to recognise novel predators, the application of inappropriate antipredator responses, and advanced hunting strategies of novel predators. This study is a preliminary attempt to explore whether the Lumholtz’ tree-kangaroo (Dendrolagus lumholtzi) (a) is able to recognise odour cues from different predators as threats, and (b) possesses predator-archetype specific antipredator responses. A small number of available captive tree-kangaroos were exposed to faecal odours from two extant predators of different archetypes (python, dingo), a regionally extinct predator which closely matches past terrestrial predators (Tasmanian devil), and a novel predator (domestic dog). Lavender oil was used as non-predator novel odour and water as control. Results suggest that all subjects associated the presented odours with a threat, albeit to different degrees, but did not display predator-archetype specific responses. It appears that this species applies an ancestral antipredator response of flight-on-the ground when encountering predators, including novel predators. Although the results need to be confirmed with more animals, further studies on the vulnerability of Australian prey to novel predators should take the ancestral history of Australian prey species into account.
Haplotype tagging reveals parallel formation of hybrid races in two butterfly species
Authors: Meier Joana I. , Salazar Patricio A. , Kučka Marek , Davies Robert William , Dréau Andreea , Aldás Ismael , Box Power Olivia , Nadeau Nicola J. , Bridle Jon R. , Rolian Campbell , Barton Nicholas H. , McMillan W. Owen , Jiggins Chris D. , Chan Yingguang Frank
Published: June 2021

Significance

A defining goal in genetics is linking variation in DNA sequence to trait evolution between populations and, ultimately, species. Genome sequencing efficiently captures such variation but typically in millions of tiny fragments that omit haplotype or linkage information. We present “haplotagging,” a simple, rapid linked-read sequencing technique that allows high-throughput sequencing without sacrificing haplotype information. We validated this affordable approach for whole-genome haplotyping in large populations. We used haplotagging to investigate the rise of a novel hybrid morph in parallel hybrid zones of two comimetic
Heliconius
butterfly species in Ecuador. Our results reveal that strikingly parallel divergences in their genomes produced coordinated shifts in haplotype frequencies across the hybrid zone, giving rise to comimetic hybrid morphs in each species.
Niche adaptation promoted the evolutionary diversification of tiny ocean predators
Authors: Latorre Francisco , Deutschmann Ina M. , Labarre Aurélie , Obiol Aleix , Krabberød Anders K. , Pelletier Eric , Sieracki Michael E. , Cruaud Corinne , Jaillon Olivier , Massana Ramon , Logares Ramiro
Published: June 2021

Significance

The oceans are populated by an astronomical number of predominantly uncultured microbes, which altogether guarantee ecosystem function. Unicellular eukaryotic predators represent basal links in marine food webs and have so far been predominantly characterized as a functional group, despite having different ecologies and evolutionary histories. In order to better understand the ecoevolution of the ocean’s smallest predators, we have investigated four species belonging to an uncultured cosmopolitan family: marine stramenopiles (MAST)-4. Using state-of-the-art single-cell genomics and metaomics approaches, we found that members of this predatory family have different distributions in the surface ocean and different genes to degrade food, which likely represent niche adaptations. Our work highlights the importance of understanding the species-level ecology and genomics of tiny ocean predators.
Novel technologies for emission reduction complement conservation agriculture to achieve negative emissions from row-crop production
Authors: Northrup Daniel L. , Basso Bruno , Wang Michael Q. , Morgan Cristine L. S. , Benfey Philip N.
Published: June 2021

Plants remove carbon dioxide from the atmosphere through photosynthesis. Because agriculture’s productivity is based on this process, a combination of technologies to reduce emissions and enhance soil carbon storage can allow this sector to achieve net negative emissions while maintaining high productivity. Unfortunately, current row-crop agricultural practice generates about 5% of greenhouse gas emissions in the United States and European Union. To reduce these emissions, significant effort has been focused on changing farm management practices to maximize soil carbon. In contrast, the potential to reduce emissions has largely been neglected. Through a combination of innovations in digital agriculture, crop and microbial genetics, and electrification, we estimate that a 71% (1,744 kg CO
2
e/ha) reduction in greenhouse gas emissions from row crop agriculture is possible within the next 15 y. Importantly, emission reduction can lower the barrier to broad adoption by proceeding through multiple stages with meaningful improvements that gradually facilitate the transition to net negative practices. Emerging voluntary and regulatory ecosystems services markets will incentivize progress along this transition pathway and guide public and private investments toward technology development. In the difficult quest for net negative emissions, all tools, including emission reduction and soil carbon storage, must be developed to allow agriculture to maintain its critical societal function of provisioning society while, at the same time, generating environmental benefits.
Reduced levels of prostaglandin I
2
synthase: a distinctive feature of the cancer-free trichothiodystrophy
Authors: Lombardi Anita , Arseni Lavinia , Carriero Roberta , Compe Emmanuel , Botta Elena , Ferri Debora , Uggè Martina , Biamonti Giuseppe , Peverali Fiorenzo A. , Bione Silvia , Orioli Donata
Published: June 2021

Significance

Xeroderma pigmentosum (XP) and trichothiodystrophy (TTD), which may arise from mutations in the same genes, are distinct clinical entities with opposite skin cancer predisposition. Whereas XP is characterized by cutaneous photosensitivity and cancer proneness frequently associated with neurodegeneration, TTD shows hair anomalies, physical and mental retardation, and, in 50% of cases, cutaneous photosensitivity but no skin cancer despite the accumulation of unrepaired ultraviolet-induced DNA lesions. This study identifies a TTD-specific transcription deregulation of
PTGIS
(prostaglandin I
2
synthase) that results in reduced levels of prostaglandin I
2
. Reduced PTGIS is found in all TTD but not in XP patients, thus representing a biomarker for this disorder.
Flow field around bubbles on formation of air embolism in small vessels
Authors: Li Zhongnan , Li Guiling , Li Yongjian , Chen Yuexin , Li Jiang , Chen Haosheng
Published: June 2021

Significance

Circulatory air embolisms resulting from surgical procedures or deep-sea diving can cause pathophysiological responses such as pulmonary hypertension and cardio-cerebral infarction. Despite significant research on embolism treatment, underlying processes of how moving bubbles get stuck in vessels have not been fully established. To further this mechanistic understanding, we developed microfluidic and in vivo experiments to observe bubble’s stopping process and revealed that aggregation of blood cells and thrombus formation occurs on the periphery of embolism’s tail because of flow recirculation. This localized thrombus formation triggers dramatic increase in flow resistance that stops bubble’s motion. This study brings insight into the critical stage of air embolism formation and may lead to strategies for prevention and treatment of this clinically significant event.
From COVID-19 to future electrification: Assessing traffic impacts on air quality by a machine-learning model
Authors: Yang Jiani , Wen Yifan , Wang Yuan , Zhang Shaojun , Pinto Joseph P. , Pennington Elyse A. , Wang Zhou , Wu Ye , Sander Stanley P. , Jiang Jonathan H. , Hao Jiming , Yung Yuk L. , Seinfeld John H.
Published: June 2021

Significance

We capitalize on large variations of urban air quality during the COVID-19 pandemic and real-time observations of traffic, meteorology, and air pollution in Los Angeles to develop a machine-learning air pollution prediction model. Such a model can adequately account for the nonlinear relationships between emissions, atmospheric chemistry, and meteorological factors. Moreover, this model enables us to identify key drivers of air-quality variations and assess the effect of future traffic-emission controls on air quality. We unambiguously demonstrate that the full benefit from fleet electrification cannot be attained if focused only on mitigation of local vehicle emissions. To continue to improve air quality in Los Angeles, off-road emissions and those from volatile chemical products need to be more strictly regulated.
Structure of AMH bound to AMHR2 provides insight into a unique signaling pair in the TGF-β family
Authors: Hart Kaitlin N. , Stocker William A. , Nagykery Nicholas G. , Walton Kelly L. , Harrison Craig A. , Donahoe Patricia K. , Pépin David , Thompson Thomas B.
Published: June 2021

Significance

Anti-Müllerian hormone (AMH) plays a crucial role in male sex differentiation and female reproductive development. As such, AMH is widely used as a biomarker for measuring a woman’s fertility, estimating onset of menopause, and has been implicated in reproductive syndromes such as polycystic ovarian syndrome and premature ovarian failure. Despite its biological relevance, how AMH functions on the molecular level is not well understood. In this study, we show that AMH engages its receptor, AMHR2, using an extensive interface distinct from other type II receptors. Furthermore, we identify several regions in both AMH and AMHR2 that are responsible for specificity and required for AMH signaling.
Siglecs-7/9 function as inhibitory immune checkpoints in vivo and can be targeted to enhance therapeutic antitumor immunity
Authors: Ibarlucea-Benitez Itziar , Weitzenfeld Polina , Smith Patrick , Ravetch Jeffrey V.
Published: June 2021

Significance

Targeting myeloid cells represents a promising strategy to augment antitumor immunity and overcome resistance to existing T cell-targeting therapies. However myeloid checkpoints that can be effectively used as immunotherapy targets are still lacking. Here, we demonstrate the therapeutic potential of targeting Siglec-7 and Siglec-9 to enhance antitumor immunity in vivo. Using an immunocompetent mouse model humanized for Siglec-7/9, we show that these receptors inhibit the endogenous antitumor immune response in a tissue-specific manner. These Siglecs also restrict the response to tumor-targeting and checkpoint-targeting antibodies, highlighting their significance in combinatorial approaches to immunotherapy. Finally, we show that Siglec-7/9 blockade can significantly reduce tumor burden in vivo, supporting the use of antibodies targeting Siglec-7/9 to therapeutically enhance antitumor immunity.
Study of Ti contacts to corundum α-Ga2O3
Authors: Massabuau F , Nicol D , Adams F , Jarman J , Roberts J , Kovács A , Chalker P , Oliver R
Published: June 2021

We present a study of the electrical, structural and chemical properties of Ti contacts on atomic layer deposited α-Ga2O3 film. Ti forms an ohmic contact with α-Ga2O3. The contact performance is highly dependent on the post-evaporation annealing temperature, where an improved conductivity is obtained when annealing at 450
°C, and a strong degradation when annealing at higher temperatures. Structural and chemical characterisation by transmission electron microscopy techniques reveal that the electrical improvement or degradation of the contact upon annealing can be attributed to oxidation of the Ti metallic layer by the Ga2O3 film in combination with the possibility for Ti diffusion into the Au layer. The results highlight that the grain boundaries and inclusions in the Ga2O3 film provide fast diffusion pathways for this reaction, leaving the α-Ga2O3 crystallites relatively unaffected—this result differs from previous reports conducted on β-Ga2O3. This study underlines the necessity for a phase-specific and growth method-specific study of contacts on Ga2O3 devices.
Design and development of modified cold compaction die for fabrication of nickel-titanium composite
Authors: Singh Rajeev , Sharma Avadesh K , Sharma Ajay K
Published: June 2021

Generally, Nickel-Titanium composites are prepared by powder metallurgy (PM) process in which the design and shape of compaction die considerably influence the characteristics of the final products. The formation of circumferential cracks and higher porosity are the major issues of this process. Therefore, the work comprises the design and fabrication of a modified cold compaction die by incorporate one additional part named as liner that prepared the Nickel-Titanium composite without circumferential cracks. The work includes design calculations, modeling and die fabrication. The die design was evaluated by SOLIDWORKS 2017-18 in a simulated conditions, and further examined experimentally by fabricating the Nickel-Titanium composite at 140 kN compaction load using UTM. The results showed that a crack-free dense Nickel-Titanium composite was successfully fabricated by this modified die. The densification, compressive strength and Rockwell hardness of NiTi composite fabricated using this die were achieved upto 86.7 %, 108.29 MPa and 64.2 HRC.
Feature curve extraction from data points
Authors: Gautam Sushant , Agrawal Vandana
Published: June 2021

In the present work, study is done for the extraction of feature curves from data points lying on the surface of object or model. Here, the reconstruction of feature curves is proposed by intersection of plane pairs. These plane pairs approximate the adjacent regions of the feature. Feature of the object may be its edges, corners, holes, sudden jerks, slits etc. Points cloud is generated from the snapshots of the object taken from various viewing angles. Clustering work is extended from K-means clustering to combined K-means and Normal (attribute) approach based clustering as it utilizes the benefits of both K-means and attribute based method and segmented the data points so that a cluster is represented with similar normal vector. Planes are fitted to all clusters based on Least Square Plane Fitting (LSPF) method and line segments from their intersection are identified, highlighted and collected as feature lines i.e. edges and corners based on developed algorithm.
Review on advance tubular receivers for central solar tower system
Authors: Kulkarni Kaustubh , Havaldar Sanjay , Bhattacharya Nabharun
Published: June 2021

This review focused on central tubular receiver modelling to obtain concentrated solar energy. Required specifications involved with efficient low cost receiver with suitable material which able to absorb concentrated solar radiations. This type of advance receivers shows excellent performance in the commercial and domestic applications. Review shows compiles literature engaged in mechanical and thermal modelling of receiver. Also highlighted on various geometries, tube sizes and various heat transfer fluids and their effect on overall performance of receiver. Recently authors concentrated on CFD simulations of different kind of receiver and put forth advanced design which offers superior flexibility and accuracy also explains stresses generated in the tube of receiver. The selection of stress theory is impacting on the mechanical life of the receiver with different approaches presented. Extensive technical analysis is investigated on different receivers for internal and external tubular geometry. Effect of heat transfer for different geometry is also observed. In this paper different aspects discussed thoroughly like receiver design, Numerical simulation, outdoor and indoor testing facilities, thermal efficiency and desired outlet temperature, benefits, future challenges, and research needs.
A critical review on wear and corrosion of carbide free bainitic steel
Authors: Sharma Siddharth , Tripathi Ajay , Dwivedi Ravi Kumar , Kumar Rajan , Agarwal Anupma
Published: June 2021

Different research on wear and corrosion of CFB (carbide free bainitic steel) over the past two decades has enabled a better understanding and advanced applications of CFB steel. With the help of advanced testing techniques, and equipment the detailed study of microstructure and nanostructured steels has been possible. The earlier years were focused on comparison of the bainite steel with the steel which is quenched and tempered (QT) for identifying the wear tendencies and comparison between carbon free bainite and martensite for the corrosive behavior of the carbide free bainitic steel. Later the trend shifted towards the nanostructured analysis from microstructure analysis with the improvement in the instruments. Advancements like HT-CAT i.e., high temperature continuous abrasion tester have an important role to play, the mechanism of material removal rate studied. There has also been development in alloying the bainite to reduce the corrosion rate and give more strength. Current trends in the form of study of wear and corrosion of carbide free bainitic steel and future needs are discussed hereby.
Seismic analysis of tall concrete and steel diagrid structure using response spectrum and time history method in e-tabs
Authors: Satya Sai Kiran Chowdary M , Himath Kumar Y , Lingeshwaran N
Published: June 2021

In the recent years due to lack of land the construction of high rise buildings widely increases and these buildings are affected by lateral loads due to wind or earthquake. To resist these horizontal loads lots of construction methods are available. Herein system peripheral columns of the building are eliminated.To resist the seismic forces we arrange the diagonal columns. In this study seismic performance of 20-story concrete and steel diagrid structures are assessed using response spectrum method. Only for concrete diagrid structure using time history method. The present work is made for studying the response and time period with acceleration of high rise building with concrete and steel diagrid structural system. To this aim response of two different diagrid structures of G+20 storey are carried out to obtain optimized position of diagrid. E-Tabs software mainly focus on seismic analysis of response spectrum and time history method. As per IS456:2000 and IS800:2007 all structural members of diagrid model are designed and IS1893:2002 and ASCE7-10 is considered for seismic analysis for concrete and steel diagrid structure. An evaluation of constraints storey shear, storey drift, storey displacement, Time period and Structural weight is done to determine the efficient and cost effective structure. The analysis of the building is carried out by using ETABS software.
Dynamic analysis of laminated composite sandwich plates with a circular hole
Authors: Kumar Deepak , Kallannavar Vinayak , Kattimani Subhaschandra , Rajendra Prasad Reddy B.
Published: June 2021

The current manuscript pacts the finite element investigation of the modal characteristics of the laminated composite sandwich (LCS) plate containing a circular hole. A series of simulations are executed to examine the influence of fiber orientations, edge constraints, the ratio of the thickness of core to face sheet, the radius of hole, and location of the hole on the system on the frequency response of the system. The analysis are carried out using ANSYS simulation tool
Parametric analysis of hole circularity for laser percussion drilling of carbon fibre reinforced plastic using Nd: YAG laser
Authors: Mishra Yadvendra Kumar , Mishra Sanjay , Jayswal S C , Suryavanshi Ajay
Published: June 2021

Holes of diameter less than 1 mm has wide application of manufacturing sector. Laser beam can be conveniently used for creation of such hole in different materials. The Carbon Fiber Reinforced Composite (CFRP) is quickly replacing the conventional materials in most of the engineering applications. Therefore, a detail parametric study to analyse the influence of factors like laser current, laser interaction time, pressure of assist gas, workpiece thickness and incidence angle on the geometrical accuracy of hole in terms of hole circularity at top (HCT) has been explored by changing the individual contributing factors. Small holes (< 1mm) have been fabricated with Nd: YAG laser of millisecond pulse duration in CFRP workpiece of thickness 1mm, 3mm, and 5 mm. It was observed that hole circularity at top surface is highest for zero angle of incidence. The increase of laser current, interaction time, and pressure of assist gas increases the HCT when the laser direction is normal to the workpiece whereas it shows a decline trend when the angle of incidence of 10° and 20°g;. The increase of workpiece thickness reduces the HCT irrespective of angle of incidence.
Palm oil fuel ash as partial substitute to cement in concrete: performance at elevated temperatures
Authors: Narayana Rao U.V. , Venkata Sairam Kumar N.
Published: June 2021

In this paper, the palm oil fuel ash (POFA) concrete is produced using POFA as partial replacement to ordinary Portland cement (OPC 53 grade) (0%-P0, 20%-P20, 40%-P40 and 60%-P60) by weight. The POFA concrete specimens are subjected to elevated temperatures of 200°C, 400°C and 800°C for duration of 2 hours. The compressive strength, ultrasonic pulse velocity (UPV) and mass loss (%) of POFA concrete are evaluated. The results indicate that the compressive strength is enhanced by the use of POFA in concrete. At elevated temperatures, POFA concrete showed higher resistance than P0 concrete (control concrete) and P20 concrete showed best performance in POFA concrete, when subjected to elevated temperatures. From the experimental results, it can be observed that 20% POFA can be used as partial replacement to cement in producing sustainable concrete.
Optimization of structural health monitoring attributes under variable failure rate condition using teaching learning based optimization and multiple regression
Authors: Khaira Ashish , Dwivedi Ravi K. , Jain Sanjay
Published: June 2021

The manufacturing industries prefer to use exponential equations for evaluating reliability, failure rate, etc., while assuming failure rate constant, but in real life failure rate is not always constant. This research work proposes a novel combination of Multiple Regression and Teaching Learning Based Optimization (TLBO). This work starts with regression modeling, to form an objective function from available data; secondly TLBO technique used, to obtain optimum values of structural health monitoring (SHM) attributes through cost minimization and finally, Weibull analysis to check the effect of optimum values of SHM attributes on β. The final results indicated that the β parameter reduces, which symbolized reduction in failure rate & SHM cost and, improvement in system reliability, thus validates the adopted methodology of combing multiple regression with TLBO, thus success of this work become the backbone for intelligent structures for SHMsystem.
Polymer nanocomposites with nanostructured copper flakes for protection as barrier in packaging materials in food industry
Authors: Karbari Sudha R , Prasad Shetty Kiran Guru , Desai Nivedita S
Published: June 2021

Polymer nanocomposites as multilayered and single layer are used as barrier protection for the entry of UV and moisture. Here the polymer nanocomposites with novel nanoflakes are simulated with the optimized geometry of nanoflakes. The barrier properties are verified with the change in width of the dispersed nanoflakes of polymer matrix. The optimization of the copper nanoflakes is investigated and studied using two model with different dimensions of the nanoflakes in the polymer nanocomposite. The diffusivity flux at the interface of air and the polymer matrix varies from 5×10-12 mol/(m 2s) and 4 ×10 -5 mol/(m 2s) for the models proposed.
Effect of notch fillet radius on tensile strength of 817M40 notched bar
Authors: Singh Aditya , Chauhan Premanand S , Pandit Prem Prakash , Narwariya Manoj
Published: June 2021

817M40 steel is a popular grade of hardening alloy steel to its excellent machinability. It is manufactured the mechanical components like gears, shafts, studs and bolts. Its hardness in the range of 248/302 HB. In this paper, notch fillet radius effect on tensile loading was investigated. U-shaped notched bars with three different kinds of notch were employed for tensile testing specimens. The changing the notch root radius and keeping the gross diameter, net diameter and notch depth same for all the notches. The notch root radius is varied as 0.5, 1.0 and 1.5 mm. The experimental results were validated with simulation result conduction on Finite Element Tool ANSYS Workbench. Authors belief that different notch fillet radius may have significant impact on tensile strength.
Investigating the influence of single-pass and double-pass friction stir processing on mechanical and wear behaviour of AA5083/Al2O3 surface
Authors: Bharti Shalok , Ghetiya Nilesh D. , Patel Kaushik M. , Dutta Varun
Published: June 2021

Friction Stir Processing (FSP) has established itself as an efficient technique to manufacture surface composite. Since the development of FSP, a variety of surface composite coatings have been produced with the help of this technique. Surface composite provides an enhancement in the material’s properties by providing a coating layer of composite material on the parent material. Various FSP process parameters can affect the produced surface composite and its properties. One of the important FSP parameters includes the number of passes over the surface of a material. In this paper surface composite of AA5083/Al2O3 was produced using FSP. Single-pass and double pass FSP were employed to understand its effect on microhardness, tensile strength, microstructure coefficient of friction, and wear rate. It was observed that the double pass aided to produce the homogeneously dispersed reinforcement particles in the surface composite along with fine grain microstructure. FSP helped to enhance the microhardness from 79.5 HV in the parent material to 136.5 HV in double pass FSP. Moreover, FSP helped to increase the tribological properties after two passes. However, the ultimate tensile strength was reduced after FSP.
Design and optimization of piezo resistors for a graphene based MEMS ICP sensor
Authors: Karbari Sudha R , Vahvale Yathish D , Kumar Karthik
Published: June 2021

Modeling and simulation of MEMS Intracranial pressure sensor using Graphene as the structural layer is defined. At normal health condition, the ICP pressure is in the range of 10-15 mmHg. Any variation from this range will signify the abnormalities such as neural system malfunction, nausea, vomiting, paralysis, brain tumor rupturing, and excitement.For Intracranial pressure sensing applications, to measure this slight variation of pressure a sensor having high sensitivity need to be employed and is solely depends on membrane used. properties of high young’s modulus, high thermal stability and electrical conductivity, inertness and zero band gap made it biocompatible to fabricate Intracranial piezoresistive pressure (ICP) sensor with membrane as graphene. COMSOL Multiphysics tool which is a finite element analysis (FEA) is deployed to optimize the dimensions and parameters for using graphene as a structural layer for pressure sensor diaphragm. A variability study of piezo resistors with three different meander shape are designed and simulated in COMSOL. The optimum design is further analyzed for three different type of pressure sensor specifications as conventional, with n-type dopant and graphene as a structural layer. The design with three meander resistance and graphene as a structural layer provides a strain induced of 0.14 with the pressure input of 10 mmHg.
Material Selection for Vertical Axis Tidal Current Turbine using Multiple Attribute Decision Making (MADM)
Authors: Musabikha S , Pratikno H , Utama I K A P , Mukhtasor
Published: June 2021

Marine renewable energy technology has attracted many stakeholders to develop due to its enormous resources and future potential advantages. One of them is the vertical axis tidal current turbine technology, which converts the kinetic energy of flowing seawater to be electrical energy. To operate the vertical axis tidal current turbine, especially its metallic components of the supporting structure, it is required to endure the aggressive and corrosive marine environment. Thus, deciding the good and suitable material for this application is very important in order to reduce the risk and hazards from the sea environment. The purpose of this paper is to decide the best metal material for the support structure of the vertical axis tidal current turbine. Therefore, the material candidate and their properties were firstly reviewed and discussed. Then, the material selection was processed through Multiple Attribute Decision Making (MADM) and formulated via the method of a Technique for Order Preference by Similarity to the Ideal Solution (TOPSIS). The result of material selection was carbon steel AISI 1045 as the selected material instead of other candidates such as carbon steel AISI 1018, stainless steel, and nickel aluminium bronze. Thus, it is expected to perform well to be used for the support structure and endure the marine hazards during the vertical axis tidal current turbine application.
Integrated Information System for Customer Care
Authors: Riananingrum D , Hari R R S , Nursaori F , Astuti WA
Published: June 2021

The application of customer Facing and Ecosystem Facing is implied as computerization of customer data. The goal is to understand customers’ needs and expectations to establish good relationships with customers. This study aims to determine Customer Facing and Ecosystem Facing services in the digital transformation business. The research method used a descriptive research method with a qualitative approach. Customer Facing and Ecosystem Facing is a technology that can increase the production process for business. Salespeople are faster to create and send offers to clients because it provides CRM information.
The Study of Main Component of the High Temperature Gas-cooled Reactor Balance of Plant using Local Component
Authors: Aji Setiawan Muksin , Pancoko Marliyadi , Kiswanta  , Bakhri Syaiful
Published: June 2021

National Nuclear Energy Agency (BATAN) as a research and development institution related to nuclear energy has designing Nuclear Power Plant (NPP) as one of the solutions to meet energy needs in Indonesia. This alternative electric power plant can be used as back up of fossil base power plant and maintaining the basic load of electric consumption. This research purpose is to simulate the balance of plant of the designed NPP and comparing the main component need to be produce by local industry. The simulation was created using Chemcad software to describe the process and component analysis of the NPP. The simulations done also can be increase the economic efficiency. Simulation results show the component data which can be used as a reference for the selection of the main components and pipes would be used in the construction of the reactor. The simulation results data of this simulation also can be uses to decide the local component that can apply in future NPP.
Breeding systems of naturalized versus indigenous species provide support for Baker’s law on Pohnpei island
Authors: Yomai Viann Marie Harmony , Williams Joseph Hill
Published: June 2021

The factors that facilitate successful colonization of islands should be especially evident where the establishment filter is strongest. Colonizers of small, remote oceanic islands should be initially rare, extremely mate-limited and often without pollinators. Hence, plant communities on such islands should reflect an establishment history in which young ‘naturalized’ species are most likely to display self-compatibility and autonomous selfing, whereas ‘indigenous’ species may exhibit more diverse reproductive strategies. To test this prediction, we characterized breeding systems of 28 species on Pohnpei, in the Federated States of Micronesia, a group of remote Pacific islands that are considered a global biodiversity hotspot. Three families with both naturalized and indigenous species were selected—Fabaceae, Malvaceae and Melastomataceae. Measurements included field observations of dichogamy/herkogamy and floral attraction traits, pollen:ovule (P:O) ratios and experimental hand-pollinations for self-compatibility and pollen limitation. Phylogenetic generalized least squares analyses tested for trait correlations between naturalized and indigenous species. Flowers of all 28 species were bisexual, and pollinator attraction features were common. Pollen:ovule ratios ranged from 9 to 557 (median = 87), and all 11 hand-pollinated species were self-compatible. All species had >5 ovules and <3500 pollen grains per flower. Indigenous species did not differ significantly from naturalized species for any trait. There is a dearth of data from remote islands bearing on the question of establishment history. In this study, we inferred all species to have some degree of autogamy and indigenous species were no more likely than naturalized species to display outcrossing mechanisms. On Pohnpei, high ovule numbers, and the inaccessibility of wind pollination and obligate outcrossing strategies, reflect the importance of retaining reproductive assurance mechanisms in the face of pollinator uncertainty.
The Swedish textile conservators’ transformation: From the museum curator’s assistant to a profession in its own right
Authors: Nilsson Johanna M , Blume Katarina S
Published: June 2021

Over recent years, in Sweden, the vocation of textile conservator has been transformed from that of being regarded simply as a museum curator's assistant to becoming a profession in its own right. The members of the textile conservators association, the Swedish Association for Textile Conservation founded in 1967, played a crucial role in this transformation with the establishment of a university-based vocational education programme in 1985. The transformation is further scrutinized by considering aspects of gender where, for example, gender bias employment strategies favoured men as painting conservators, as well as social class where demarcation of women as curators was evident. This is discussed and compared with the contemporary shift of gender distribution among the employees in the museum sector that historically was largely male dominated. Social class and the effects of a university education on occupational status are considered, and the effects that education had on elderly, experienced colleagues are another important intersectional aspect. Today’s textile conservators have reached a professional status in several aspects with university education being probably the most important contributing factor. The image of the vocation has improved from that of a seamstress who performed repairs on textiles at the direction of her superior, to an academic who, on the basis of their scientific knowledge, independently performs the many tasks included in preservation, as well as conducting research to doctorate level. Despite this, it would seem that the museum community has not yet managed to take full advantage of textile conservators’ competence as researchers.
Clinical and Angioarchitectural Features of Hemorrhagic Brain Arterio-Venous Malformations in Adults and Children: Contrasts and Implications on Outcome
Authors: Qureshi Ayman M , Muthusami Prakash , Krings Timo , Amirabadi Afsaneh , Radovanovic Ivan , Dirks Peter , Shroff Manohar , Armstrong Derek , terBrugge Karel , Pereira Vitor M
Published: June 2021

BACKGROUND

Hemorrhage from brain arteriovenous malformations (bAVMs) is estimated at 3% per annum. Features influencing risk of hemorrhage include perforator/posterior circulation supply, associated aneurysms, and deep drainage. Children are more likely to present with bAVM bleeds.

OBJECTIVE

To analyze differences in bAVM angioarchitecture between children and adults and describe predictors of poor outcome.

METHODS

Data were collected from adult and pediatric tertiary referral hospitals. Demographic data, bleed location, treatment, and follow-up modified Rankin Scale (mRS) were collected. Angioarchitectural assessment included aneurysm presence, nidus morphology, perinidal angiogenesis, intranidal shunting, steal phenomenon, venous ectasia, venous stenosis, venous reflux, and pseudophlebitic pattern. Regression analyses conducted to determine predictors of mRS > 2.

RESULTS

A total of 270 adult and 135 pediatric ruptured bAVMs were assessed. Median age was 42 (adults) and 10.9 (children) yr. Intranidal aneurysms were more frequent in children (P = .012), whereas prenidal aneurysms were more common in adults (P < .01). Children demonstrated more perinidal angiogenesis (P = .04), whereas steal phenomenon was commoner in adults (P < .01). Venous ectasia (P < .01), reflux (P < .01), and pseudophlebitic pattern (P = .012) were more frequent in adults. Children had better outcome (mRS score ≤ 2) (P < .01). Older age (odds ratio [OR] = 1.02), eloquent location (OR = 2.5), multicompartmental hemorrhage (OR = 1.98), venous reflux (OR = 2.5), diffuse nidus (OR = 1.83), pseudophlebitic pattern (OR = 1.96), intranidal shunts (OR = 2), and no treatment (OR = 3.68) were significant predictors of mRS > 2.

CONCLUSION

Children are more likely to have intranidal aneurysms and perinidal angiogenesis, whereas adults have more prenidal aneurysms, venous ectasia, corticovenous reflux, and pseudophlebitic pattern. Eloquent location, diffuse nidus, intranidal shunts, venous reflux, and pseudophlebitic pattern predict poorer outcome.
A real-time lucky imaging algorithm based on Fourier transform and its implementation techniques
Authors: Huang Xueming , Li Binhua , Wang Jinliang , Li Junwu
Published: June 2021

Lucky imaging is a high-angular-resolution astronomical image reconstruction technique which can effectively reduce or remove the effects of atmospheric turbulence. There have been successful real-time lucky imaging algorithms and corresponding implementations in the spatial domain. Although the results of lucky imaging algorithms in the frequency domain are better than in the spatial domain, until now there has been no corresponding real-time algorithm and implementation due to its complexity. This paper proposes a real-time lucky imaging algorithm based on Fourier transform that features real-time processing and dynamic updating and display. The algorithm is implemented on a small- or medium-scale field programmable gate array (FPGA) development board. In this system, a two-dimensional fast Fourier transform of the image is carried out by means of dimension reduction. In order to achieve real-time lucky imaging in the frequency domain, the sum of the squares of the real and imaginary parts are used to replace the amplitude for data selection, and the method of image grouping is used to speed up the data selection. Compared with other real-time lucky imaging algorithms in the spatial domain, this algorithm shows great advantages in image quality. Moreover, the system can carry out real-time lucky imaging processing in the frequency domain for more than 10000 frames of an original image of 512 × 512 pixels continuously, and dynamic display with an image of 128 × 128 pixels. The experimental results illustrate the validity of the proposed algorithm and the feasibility of the proposed implementation techniques for the FPGA-based algorithm.
Biased by Choice: How Financial Constraints Can Reduce Financial Mistakes
Authors: Heimer Rawley Z , Imas Alex
Published: June 2021

We show that constraints can improve financial decision-making by disciplining behavioral biases. In financial markets, restrictions on leverage limit traders’ ability to borrow to open new positions. We demonstrate that regulation that restricts the provision of leverage to retail traders improves trading performance. By increasing the opportunity cost of postponing the realization of losses, leverage constraints improve traders’ market timing and reduce their disposition effect. We replicate these findings in two distinct experimental settings, further isolating the mechanism and demonstrating generality of the results. The interaction between constraints and behavioral biases has implications for policy and choice architecture.