bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermal Energy Storage in Phase Change Material Integrated Solar Collectors for Air Heating Application
Authors: Tyagi V. V. , Nagilla Dheeraj Kumar , Selvaraj Jeyraj , Chopra Kapil , Kothari Richa , Pandey A. K.
Published: April 2021

Solar energy is an abundant source of renewable energy which can able to support the expansion of energy demand. This review paper represents a complete literature review on recent developments in the phase change material (PCM) based solar collectors for air heating applications such as building heating, greenhouse heating, etc. In this paper thermal efficiency of various types of storage based collector and their performance for air heating (SAH) applications have been discussed. Based on the literature, it has been found that compared to basic solar air heating (SAH) systems, the collector-storage based air heating systems are able to provide higher efficiency with their capacity to recover and utilize the stored heat at night or cold weather conditions. These storage based collectors can be efficiently utilized for applications requiring medium operating temperature range during daytime as well as night times.
Recent Advancements in Design of Flat Plate Solar Collectors
Authors: Chopra K. , Pathak Pratik Kumar , Samykano Mahendran , Tyagi V. V , Pandey A. K
Published: April 2021

Solar collector is an important technology for the effective utilisation of solar energy that the earth is blessed with. Flat plate solar collectors present a simple and easy to maintain design and thus are widely used for low and medium temperature applications. But being less efficient than alternatives, justifying the initial investment of flat plate solar collectors becomes difficult in the long run. This paper presents the efforts of researchers in the past some years to improve the efficiency of flat plate solar collectors through the improvement and optimization of the existing design. The range of research work covered gives a general idea of the variety of techniques being developed, analysed and tested to increase the efficiency of flat plate solar collector through means such as new absorber design, design of absorber tubes, new coatings on glass cover, and other means to reduce heat transfer losses, increase heat transfer from absorber to working fluid and absorbing and retaining direct as well as diffuse radiation. Design and efficiency improvement for better adoption of flat plate collectors in building facades has also been discussed. This paper will be beneficial for exploring the range of research avenues in the field of optimization and efficiency improvement of flat plate solar collectors.
Review on Economic analysis of Photovoltaic Thermal Systems
Authors: Kalidasan B , Divyabharathi R , Pandey A K , Saidur R.
Published: April 2021

Sun is the most promising renewable resource available to mankind for extracting maximum useful energy. One of the best ways to trap solar energy is to install photovoltaic thermal (PVT) systems whose main novelty is to produce power by photovoltaic conversion and also dissipate the heat evolved to recover thermal energy thereby enhancing the overall efficiency of the system. Implementing this approach in practical application system lags mainly due to the requirement of economic investment. This paper reviews on the economics involved in the installation, operation and maintenance of solar PVT systems. The economic viability of solar PVT systems is evaluated by considering five criteria (energy costs, life cycle costs, profit ratio, cost savings and pay-back period). Furthermore the performances of many PVT systems were compared and the economic evaluation has proved that the PVT system is economically feasible and has greater potential for incorporating in residential/commercial buildings especially for tropical countries like India.
Investigation on Thermal Properties of AL2O3 Based Phase Change Material Composite for Solar Thermal System Application
Authors: George Mathew , Pandey A. K. , Rahim Nasrudin Abd , Shahabuddin Syed , Tyagi V.V. , Saidur R.
Published: April 2021

Sustainable Development Goal and Paris Agreement are guidelines provided by the global community for a better future. One of the ways is through the utilization of solar energy. But solar energy is plagued by unpredictable energy delivery, which can be solved through latent heat energy storage system. In this study, a phase change material (A70) composite with 0.1% wt Al2O3 is prepared using probe sonication. The composite is characterized through Differential Scanning Colorimetry (DSC), Thermogravimetric Analyzer (TGA) and UV-VIS-NIR spectrometer. The DSC showed a 5.02% decrease in the value of latent heat while the composite was thermally stable for the temperature range 30 °C to 200 °C where majority of domestic solar application lies. The composite and pure A70 may be useful for thermal system application where indirect heat absorption like heat exchangers, heat sinks, photovoltaic thermal and concentrated photovoltaic thermal system.
A Brief Review on Conducting Polymer Nanocomposite Based Epoxy Coatings for Marine Applications
Authors: Fitriya A.M , Shahabuddin Syed , Sridewi Nanthini , Norsyarizad M. , Pandey A.K.
Published: April 2021

Recently, fouling has become the main concern in the marine, naval and shipping industries. Furthermore, fouling has caused an increase in ship drag and fuel consumption whilst reducing the hydrodynamic performance of ships. Marine structures that partly or fully submerged such as oilrigs, submarine pipes and marine buoys are also impacted. Therefore, research and numerous studies had conducted to propose the best antifouling coating. The main objective of this review is to provide an overview of polymer-based surface coatings for protection from marine biofouling organisms. The physicochemical and mechanical properties of polymers had found to make these materials promising as polymeric coating that can be used in marine applications. Furthermore, this review will discuss the utilization of nanocomposites as additives, modifiers and nanofillers in order to enhance the properties of the polymer for antifouling coating.
Design and performance testing of a bread box type low cost solar water heater for rural area
Authors: Htike Than Than , Mon Mi Sandar , Tin Saw Ba
Published: April 2021

This paper deals with the design of integral passive low cost solar water heating system of “Bread Box” type for rural area. The designed capacity is 200lit and aims to cover the need of hot water at evening/night and morning for one to three people. This type of heater consists of horizontal cylindrical Mild-Steel tank painted flat black and is enclosed in a glazed (glass) insulated rectangular wooden box whose lid and front are opened as reflector (mercury-backed mirror) during the day and closed as insulation at night. In this research, bread box solar water heater was designed and constructed with local materials and then, this heater was tested. In this design, the diameter of collector-storage tank is 0.55 m, its length is 0.797 m and collector area is 1.377m2. The total glazing area of this heater is 1.859 m2 and box size is 1.341m x 0.884m x 0.76m.
Japan Solar PV manufacturing in the past and future
Authors: Ishihara Keiichi N.
Published: April 2021

Over the past 10 years, the number of solar power generation systems installed around the world has increased rapidly, partly due to the strengthening of measures against global warming. Chinese companies meet most of the demand. While the installation of PV in developed countries is declining, the demand in China, the Middle East, and Southeast Asia are expected to grow continuously. Meanwhile, Chinese exports to the United States declined sharply due to trade friction between the two countries. In this work, the Japan market mechanism of solar PV was investigated to consider how they can survive in the future. Firstly, the historical trend of Japanese solar PV production in the domestic market is reviewed. It is indicated that the Japanese consumer has selected Japanese product even it is expensive. Because they can sell electricity by a reasonable price under the FiT scheme and spend more money on construction to protect from natural disasters. Recently, both Japanese and Chinese companies start to produce solar PV cells outside the country. The production price becomes competitive in the future. The hot production countries in southeast Asia are Malaysia and Vietnam.
Barrier Analysis for Deployment of Renewable Energy Mini-grids in Myanmar Using AHP
Authors: Numata Masako , Sugiyama Masahiro , Mogi Gento
Published: April 2021

Energy access is still a challenge for many countries, as demonstrated by Sustainable Development Goal (SDG) 7. Though the government of Myanmar set a target of 100% electrification by 2030, currently only less than half of households are connected to national grids. To accelerate electrification, decentralized approaches should be considered more. Mini-grids are an effective option that can fill the gap between a solar home system and a national grid. However, many of the existing mini-grids in Myanmar are powered by diesel generators. In rural areas, diesel fuel is much more expensive than in urban areas because of transportation cost. Under this condition, mini-grids powered by solar photovoltaics and batteries are already cost-competitive with diesel generators. Nevertheless, the deployment of mini-grids powered by renewable energy is still slow. In this study, we analysed barriers to the deployment and the prioritization of these barriers. We conducted a questionnaire survey with stakeholders using the analytic hierarchy process (AHP) to identify the prioritization of each barrier factor. To see tendencies, we used k-means for clustering results. The results showed that opinions were divided among stakeholders. There is no single silver bullet for the mini-grids and overcoming the barriers needs steady work.
A review paper related to the various variable’s measurements on the relationship between environmental performance and financial performance
Authors: Wu Qichun , Furuoka Fumitaka , Pui Kiew Ling
Published: April 2021

The present-day environmental concerns have provided an incentive for firms to reduce environmental pollution by the reduction in resource consumption which in turn reduces the carbon emissions and other pollutants. To achieve the stakeholder requirement, the firm needs to improve the environmental management system, utilize environmentally friendly activities and strategies for efficient utilization of materials. Different results (positive, negative, no influence) have been documented in previous articles. This study focusses on the measurement of variables and the result of these papers. An inconsistent result has been found between Corporate Environmental Performance (CEP) and Corporate Financial Performance (CFP) relationship, for a sample of 63 empirical studies. In general, environmental performance is positively related to corporate financial performance. The result indicates the variety of environmental variables influencing the results. It is demonstrating that financial benefits (both accounting-based, market-based and others) are more from environmental management and environmental pollution than environmental disclosure. But there is no obvious evidence to demonstrate different financial variables can lead to different correlations.
Electromagnetic torque capabilities of permanent magnet flux-switching machine using modular rotor
Authors: Soomro Irfan Ali , Sulaiman Erwan , Soomro Hassan Ali , Amin Faisal
Published: April 2021

The use of a segmented rotor electric motor for lightweight electric vehicle applications has gained a lot of attention since the motor must have a high output torque and output power. Segmented rotor motors have performance indices that should be taken into consideration because not every machine is effective. Recently, permanent magnet flux switching machine (PMFSM) in salient rotor has become attractive for provide high torque and power. Undesirably, salient rotor inherited high iron loss and winding loss, Furthermore, PMFSM uses high PM volume and more flux leakage resulting in poor performance. This paper deals with a novel structure of modular rotor PMFSM with non-overlapping winding with minimal iron loss, high torque and high power. 2D finite element analysis (FEA) is used to investigate the performance of proposed motor in JMAG Designer 14.1. Three-phase operation of 12S/10P modular rotor PMFSM was designed and analysed based on the cogging torque, induced back emf, output torque and output power performances. The proposed motor securing the initial torque of 33.30 Nm and power of 12Kw at maximum current density of 30Arms/mm2. From the result it is concluded that modular rotor based PMFSM motor is suitable for light weight electric vehicles.
Influence of Various Tooth Shape Topology for Single-Phase Permanent Magnet Flux Switching Machine
Authors: Jusoh Laili Iwani , Sulaiman Erwan , Ahmad Md Zarafi , Soomro Irfan Ali , Soomro Hassan Ali
Published: April 2021

Permanent magnet flux switching machine (PMFSM) has the advantages of solid design structure, high torque performances, and high efficiency. The method to increase performance and decrease the cost of the motor through a selection of numbers of slot and pole is a major issue that needs to be solved. Therefore, to further improve the electromagnetic torque, a novel 4-4S-8P multi-tooth, 4S-8P segmental-tooth and single-tooth PMFSM machine respectively is proposed based on the slot pole analysis performance. Hence, the performance is including the flux linkage, cogging torque, back-electromotive force (back-emf), output torque, and power performance. The results display that the various tooth shape topology have a large impact on the performance design. JMAG Designer version 14.3 under 2D finite element analysis (2D-FEA) are used to complete the analysis. The results show that the right combination of a single-tooth 4S-8P PMFSM structure is the best choice according to the high performance of torque analysis.
Using Nonlinear Load DC Variables as Inputs for Harmonic Current Reduction
Authors: Yusof Yushaizad , Abd.Rahim Nasrudin
Published: April 2021

This paper introduces and discusses new inputs for a single-phase shunt active power filter (SAPF) using nonlinear load equivalent resistance estimation control strategy. The inputs are an average DC voltage and current of a current source nonlinear load. By using a MATLAB Simulink simulation tool, a model of single-phase AC system connected to the SAPF and nonlinear load is designed and its vital voltage and current variables are simulated. Various simulation results are presented and analysed in order to validate the effectiveness of proposed inputs. As a conclusion, the proposed control strategy with new inputs successfully achieved its objective to mitigate harmonic current and to compensate the reactive power with good performance.
Effects of Generator Ratings on Inertia and Frequency Response in Power Systems
Authors: Qaid Khaldon Ahmed , Gan Chin Kim , Salim Norhafiz Bin , Ibrahim Khairul Anwar
Published: April 2021

The increasing share of renewable generation integrated in the traditional power systems network has brought new challenges to the utility. More specifically, the high penetration of solar energy in the network will reduce the total system inertia which could jeopardize the system’s stability during contingency. The lack of inertia in the power system will increase the Rate of Change of Frequency (RoCoF), which is harmful in the event of sudden load change. In this regard, this paper analyses the effects of generator ratings on system’s inertia and frequency response. The IEEE 9-BUS test system has been utilized in this paper to model the system’s inertia response under various contingency scenarios. The results show that small rating of generators can achieve 20% higher inertia response as compared to the case with larger generator ratings. This implies that system with smaller generators can better recover the system’s frequency than the large-scale generators of similar total rating.
PV Inverter with Decoupled Active and Reactive Power Control to Mitigate Grid Faults
Authors: Talha M , Raihan S. R. S. , Rahim N.A.
Published: April 2021

Low power distributed Photovoltaic (PV) systems would be a dominant power generator in future grids. This PV penetration significantly influence the grid stability, especially in an event of grid faults. Traditional PV inverters disconnect themselves from grid on detecting a low voltage at their point of common coupling (PCC). A temporary low voltage grid fault can lead to outage, if PV inverters are not equipped with low voltage ride through (LVRT) feature. During a low voltage grid fault PV inverter can assist the grid recovery process by not only staying connected to grid but also injecting reactive power into the grid. Many grid code standards have issued guidelines to inject reactive power during a low voltage fault. Development of low voltage ride through inverters require decoupled power flow control. In addition to maximum power point operation and standardized current injection to the grid, modern PV inverters should be able to deal with LVRT and loss of grid (LoG) ride through features, as demanded by the regulating grid codes. Reduction in grid outages can be achieved, if the PV inverters stay connected during LVRT, LoG and short circuit faults. Most of previous studies on LVRT control of PV inverters have not short circuit faults and loss of grid faults at PCC. This work proposed a PV inverter controller capable of controlling complex power into the grid. A decoupled current regulator with feed forward compensation is modelled. A short circuit grid fault is also tested with the developed PV inverter. It is found that the PV inverter ride through the low voltage and short circuit faults. The system is simulated in MATLAB(Simulink), the designed controller can provide decoupled active and reactive power to the grid during the fault events.
Investigate the Effect of Artificial Neural Network Parameters to Improve Fault Distance and Impedance Accuracy
Authors: Ali Mohd Syukri , Bakar Ab Halim Abu , Nasrudin Abd Rahim
Published: April 2021

This paper investigates the effect of artificial neural network (ANN) parameters against the ANN accuracy on cable fault location. The investigation is conducted through the fault impedance and distance estimations during the occurrence of high impedance fault (HIF) in the distribution system. The measured three-phase voltage and current signals are utilized and fed into the ANN to estimate the fault impedance and distance. The accuracy of the estimated fault impedance and distance is evaluated with respect to the variation of ANN parameters. Based on the analysis, it shows that more accurate results can be obtained by utilizing the optimal value of ANN parameters.
Parametric Evaluation of 11kV Zinc Oxide Surge Arrester using Finite Element Analysis Model
Authors: Nurul A.A. Latiff , Sameh Z.A. Dabbak , Hazlee A. Illias , Bakar Ab H.A.
Published: April 2021

A surge arrester on transmission line is used to deflect lightning surge to ground, avoiding power systems from destruction. During normal condition, there is a leakage current flow through surge arresters where it is one of the main causes of surge arrester humiliation. Thus, monitoring the surge arrester condition is very significant. In this work, the effect of several parameters in a 11kV zinc oxide surge arrester design based on leakage current distribution has been studied. A comparison is made between measurements and modelling in order to validate the model that has been developed using finite element analysis. This work found that the benefit of using FEA-based model where the design parameters that affect the leakage current can be identified. Through this study, a well knowledge of leakage current can be achieved and also help in zinc oxide surge arrester design.
Design of a small scale fluidized-bed incinerator for MSW with ability to utilize HHO as auxiliary fuel
Authors: Butt Osama Majeed , Ahmad Muhammad Shakeel , Che Hang Seng , Rahim Nasrudin Abd
Published: April 2021

Waste incineration has become a mature technology and widely accepted due to its environment friendliness, easy operation and ability to reduce more than 95% mass fraction. There are some inherent limitations associated with incinerators such as high fuel consumption and cite feasibility. In this study, we propose a novel design concept of small scale fluidized bed incinerator for household use, with the ability to consume brown’s gas (HHO) as primary fuel for incinerate waste. In principle, the HHO gas generated through photovoltaic (PV) integrated water electrolysis system would be feed from the bottom to provide heat energy to the waste. Theoretical design of fluidized bed type incinerator has been presented with water electrolyzer system. It was calculated that 150 lph of hydrogen is required for this proposed incinerator system which can handle 5 kg of waste.
Photovoltaic performances and lifetime analysis of TiO2/rGO DSSCs sensitized with Roselle and N719 dyes
Authors: Omar A , Fakir M S , Hamdan K S , Rased N H , Rahim N A
Published: April 2021

Two titanium dioxide/reduced graphene oxide (TiO2/rGO) based dye-sensitized solar cells (DSSCs) were fabricated and separately sensitized with natural dye extracted from Roselle flowers and ruthenium-based dye of N719. The current-voltage (I-V) performances were measured using Visiontec Solar I-V tester at standard illumination of AM1.5 and irradiance level of 100 mW/cm2. The lifetime of the TiO2/rGO based DSSCs were furtherly investigated by measuring the I-V performances of the cells on the 5thday and 15thday. The highest power conversion efficiency (PCE) of 1.233 % was measured for the photoanode sensitized with N719 dye on the 15thday. The PCE of Roselle dye dropped from 0.992 % on the 5thday to 0.897 % on the 15thday. Dye degradation and low electron injection have influenced the unstable photovoltaic performances of Roselle dye even with the presence of electron conducting path provided by the rGO particles.
P(HEMA-co-EA) as host polymer for flexible dye-sensitized solar cell (DSSC) electrolyte
Authors: Rased N H , Raihan S R S , Rahim N A
Published: April 2021

An electrolyte is the main component of a dye-sensitized solar cell (DSSC) which influences the efficiency of the DSSC. In order to prevent leakage problem and adhesive problem, new solid-state polymer electrolyte proposed rather than using a liquid electrolyte. For this research, new copolymers using 2-hydroxyethyl methacrylate (HEMA) and Ethyl Acrylate (EA) monomers are randomly copolymerized via UV-cure polymerization method with different ratio of each monomer (10,30,50,70,90) towards development as a solid-state electrolyte in flexible DSSC. In this study, the best ratio of the copolymer HEMA-co-EA will be the host polymer for electrolyte in DSSC. The most promising characteristics as a host in polymer electrolytes are due to its smooth cross-sectional surface and lowest glass transition temperature. Therefore, a best ratio of p(HEMA-co-EA) will be stirred with sodium iodide (NaI), Tetrahydro folic acid (THF) and iodine crystal for 24 hours to form a homogenous solution of an electrolyte. This p(HEMA-co-EA) will incorporate with different weight ratios of sodium iodide (NaI). This research reported that after 1500 s only three ratios of new host polymer p(HEMA-co-EA) were successfully copolymerized completely. All three ratio will be characterized by physical appearance, FTIR, DSC and XRD. By naked eyes, only 3 ratios of monomer (50HEMA:50EA, 70HEMA:30EA and 90HEMA:10EA) gave brittle structure which proved the copolymerization process completely success. For FTIR, those three ratios show the breakdown of a double bond at the HEMA monomer structure proved the complete copolymerization process. DSC shows that all three ratio shows the glass transition temperature (Tg) and only 50HEMA:50EA gave melting temperature (Tm) at 192.49°C and XRD confirmed the phase structure and crystallinity of three ratios. All these characterizations show that HEMA and EA monomers can be successfully random copolymerize with a three suitable ratio of each monomer and been used as an electrolyte for flexible DSSC.
(Quasi-)Quantization of the electrical, thermal, and thermoelectrical conductivities in two and three dimensions
Authors: Noky Jonathan , Gooth Johannes , Sun Yan , Felser Claudia
Published: April 2021

The quantum Hall effect in a 2D electron system expresses a topological invariant, leading to a quantized conductivity. The thermal Hall and thermoelectric Nernst conductances in two dimensions are also reported to be quantized in specific systems. However, a comprehensive study of these quantities within one formalism for quantum Hall systems is so far elusive. In this work, we investigate the Hall, thermal Hall, and Nernst effects analytically and numerically in 2D and 3D. In addition to the quantized values for the Hall and thermal Hall conductances in two dimensions, we also find quasi-quantized values in three dimensions, which are the related 2D quanta scaled by a characteristic length. The Nernst conductivity is not generally quantized. Instead, an integration in energy is required to obtain a universally (quasi-)quantized thermoelectric quantity.
Conformations and diffusion of flexibly linked colloidal chains
Authors: Verweij Ruben W , Moerman Pepijn G , Huijnen Loes P P , Ligthart Nathalie E G , Chakraborty Indrani , Groenewold Jan , Kegel Willem K , van Blaaderen Alfons , Kraft Daniela J
Published: April 2021

For biologically relevant macromolecules such as intrinsically disordered proteins, internal degrees of freedom that allow for shape changes have a large influence on both the motion and function of the compound. A detailed understanding of the effect of flexibility is needed in order to explain their behavior. Here, we study a model system of freely-jointed chains of three to six colloidal spheres, using both simulations and experiments. We find that in spite of their short lengths, their conformational statistics are well described by two-dimensional Flory theory, while their average translational and rotational diffusivity follow the Kirkwood–Riseman scaling. Their maximum flexibility does not depend on the length of the chain, but is determined by the near-wall in-plane translational diffusion coefficient of an individual sphere. Furthermore, we uncover shape-dependent effects in the short-time diffusivity of colloidal tetramer chains, as well as non-zero couplings between the different diffusive modes. Our findings may have implications for understanding both the diffusive behavior and the most likely conformations of macromolecular systems in biology and industry, such as proteins, polymers, single-stranded DNA and other chain-like molecules.
Adaptive partial scanning transmission electron microscopy with reinforcement learning
Authors: Ede Jeffrey M
Published: April 2021

Compressed sensing can decrease scanning transmission electron microscopy electron dose and scan time with minimal information loss. Traditionally, sparse scans used in compressed sensing sample a static set of probing locations. However, dynamic scans that adapt to specimens are expected to be able to match or surpass the performance of static scans as static scans are a subset of possible dynamic scans. Thus, we present a prototype for a contiguous sparse scan system that piecewise adapts scan paths to specimens as they are scanned. Sampling directions for scan segments are chosen by a recurrent neural network (RNN) based on previously observed scan segments. The RNN is trained by reinforcement learning to cooperate with a feedforward convolutional neural network that completes the sparse scans. This paper presents our learning policy, experiments, and example partial scans, and discusses future research directions. Source code, pretrained models, and training data is openly accessible at https://github.com/Jeffrey-Ede/adaptive-scans.
MPGVAE: improved generation of small organic molecules using message passing neural nets
Authors: Flam-Shepherd Daniel , Wu Tony C , Aspuru-Guzik Alan
Published: April 2021

Graph generation is an extremely important task, as graphs are found throughout different areas of science and engineering. In this work, we focus on the modern equivalent of the Erdos–Rényi random graph model: the graph variational autoencoder (GVAE) (Simonovsky and Komodakis 2018 Int. Conf. on Artificial Neural Networks pp 412–22). This model assumes edges and nodes are independent in order to generate entire graphs at a time using a multi-layer perceptron decoder. As a result of these assumptions, GVAE has difficulty matching the training distribution and relies on an expensive graph matching procedure. We improve this class of models by building a message passing neural network into GVAE’s encoder and decoder. We demonstrate our model on the specific task of generating small organic molecules.
Simultaneous averaging to zero by unitary mixing operators
Authors: Chand Abhinav , Robert Leonel , Sutradhar Arindam
Published: April 2021

We show that if every element of a vector subspace of a C*-algebra can be averaged to zero by means of unitary mixing operators, then all the elements of the subspace can be simultaneously averaged to zero by a net of unitary mixing operators. Moreover, such subspaces admit a simple description in terms of commutators and kernels of states on the C*-algebra. We apply this result to center-valued expectations in C*-algebras with the Dixmier property.
The nilpotent cone for classical Lie superalgebras
Authors: Jenkins L. , Nakano Daniel
Published: April 2021

In this paper the authors introduce an analogue of the nilpotent cone,

N

{\mathcal N}

, for a classical Lie superalgebra,

g

{\mathfrak g}

, that generalizes the definition for the nilpotent cone for semisimple Lie algebras. For a classical simple Lie superalgebra,

g

=

g

0
¯

⊕

g

1
¯

{\mathfrak g}={\mathfrak g}_{\bar 0}\oplus {\mathfrak g}_{\bar 1}

with

Lie 

G

0
¯

=

g

0
¯

\text {Lie }G_{\bar 0}={\mathfrak g}_{\bar 0}

, it is shown that there are finitely many

G

0
¯

G_{\bar 0}

-orbits on

N

{\mathcal N}

. Later the authors prove that the Duflo-Serganova commuting variety,

X

{\mathcal X}

, is contained in

N

{\mathcal N}

for any classical simple Lie superalgebra. Consequently, our finiteness result generalizes and extends the work of Duflo-Serganova on the commuting variety. Further applications are given at the end of the paper.
The Markus–Yamabe conjecture for continuous and discontinuous piecewise linear differential systems
Authors: Llibre Jaume , Zhang Xiang
Published: April 2021

In 1960 Markus and Yamabe made the following conjecture: If a

C
1

C^1

differential system

x

˙

=
F
(

x

)

\dot {\mathbf {x}}=F(\mathbf {x})

in

R

n

\mathbb {R}^n

has a unique equilibrium point and the Jacobian matrix of

F
(

x

)

F(\mathbf {x})

for all

x

∈

R

n

\mathbf {x}\in \mathbb {R}^n

has all its eigenvalues with negative real part, then the equilibrium point is a global attractor. Until 1997 we do not have the complete answer to this conjecture. It is true in

R

2

\mathbb {R}^2

, but it is false in

R

n

\mathbb {R}^n

for all

n
>
2

n>2

.

Here we extend the conjecture of Markus and Yamabe to continuous and discontinuous piecewise linear differential systems in

R

n

\mathbb {R}^n

separated by a hyperplane, and we prove that for the continuous piecewise linear differential systems it is true in

R

2

\mathbb {R}^2

, but it is false in

R

n

\mathbb {R}^n

for all

n
>
2

n>2

. But for discontinuous piecewise linear differential systems it is false in

R

n

\mathbb {R}^n

for all

n
≥
2

n\ge 2

.
Heights of points on elliptic curves over ℚ
Authors: Griffin Michael , Ono Ken , Tsai Wei-Lun
Published: April 2021

In this note we obtain effective lower bounds for the canonical heights of non-torsion points on

E
(

Q

)

E(\mathbb {Q})

by making use of suitable elliptic curve ideal class pairings
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="normal upper Psi Subscript upper E comma negative upper D Baseline colon upper E left-parenthesis double-struck upper Q right-parenthesis times upper E Subscript negative upper D Baseline left-parenthesis double-struck upper Q right-parenthesis right-arrow from bar normal upper C normal upper L left-parenthesis negative upper D right-parenthesis period">

Ψ

E
,
−
D

:
 
E
(

Q

)
×

E

−
D

(

Q

)
↦

C
L

(
−
D
)
.

\begin{equation*} \Psi _{E,-D}: \ E(\mathbb {Q})\times E_{-D}(\mathbb {Q})\mapsto \mathrm {CL}(-D). \end{equation*}

In terms of the class number

H
(
−
D
)

H(-D)

and

T
E

(
−
D
)

T_E(-D)

, a logarithmic function in

D
D

, we prove
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="ModifyingAbove h With caret left-parenthesis upper P right-parenthesis greater-than StartFraction StartAbsoluteValue upper E Subscript normal t normal o normal r Baseline left-parenthesis double-struck upper Q right-parenthesis EndAbsoluteValue squared Over left-parenthesis upper H left-parenthesis negative upper D right-parenthesis plus StartAbsoluteValue upper E Subscript normal t normal o normal r Baseline left-parenthesis double-struck upper Q right-parenthesis EndAbsoluteValue right-parenthesis squared EndFraction dot upper T Subscript upper E Baseline left-parenthesis negative upper D right-parenthesis period">

h
^

(
P
)
>

|

E

t
o
r

(

Q

)

|

2

(
H
(
−
D
)
+

|

E

t
o
r

(

Q

)

|

)

2

⋅

T
E

(
−
D
)
.

\begin{equation*} \widehat {h}(P)> \frac {|E_{\mathrm {tor}}(\mathbb {Q})|^2}{\left ( H(-D)+ |E_{\mathrm {tor}}(\mathbb {Q})|\right )^2}\cdot T_E(-D). \end{equation*}
Inertial manifolds for a singularly non-autonomous semi-linear parabolic equations
Authors: Li Xinhua , Sun Chunyou
Published: April 2021

This paper devotes to the existence of an

N
N

-dimensional inertial manifold for a class of singularly, i.e.

A
(
t
)

A(t)

may degenerate to

0
0

at some time

t
t

, non-autonomous parabolic equations
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="partial-differential Subscript t Baseline u plus upper A left-parenthesis t right-parenthesis u equals upper F left-parenthesis t comma u right-parenthesis plus g left-parenthesis x comma t right-parenthesis comma t greater-than tau semicolon u vertical-bar Subscript t equals tau Baseline equals u Subscript tau Baseline left-parenthesis x right-parenthesis comma x element-of normal upper Omega comma">

∂

t

u
+
A
(
t
)
u
=
F
(
t
,
u
)
+
g
(
x
,
t
)
,

t
>
τ
;

u

|

t
=
τ

=

u

τ

(
x
)
,

x
∈
Ω
,

\begin{equation*} \partial _{t}u+A(t)u=F(t,u)+g(x,t),\;t>\tau ;\; \; u|_{t=\tau }=u_{\tau }(x),\;x\in \Omega , \end{equation*}

where

A
(
t
)
≥
0

A(t)\geq 0

for any

t
≥
τ

t\geq \tau

, and

Ω
⊂

R

d

\Omega \subset \mathbb {R}^{d}

is a bounded domain with smooth boundary. Since the operator

A
(
t
)

A(t)

may degenerate, a compatibility condition for the operator

A
(
t
)

A(t)

and the nonlinear term

F
(
t
,
u
)

F(t,u)

was proposed to construct the inertial manifolds.
Protein turnover dynamics suggest a diffusion-to-capture mechanism for peri-basal body recruitment and retention of intraflagellar transport proteins
Authors: Hibbard Jaime V. K. , Vazquez Neftali , Satija Rohit , Wallingford John B.
Published: April 2021

Fluorescence recovery after photobleaching of intraflagellar transport (IFT) proteins in a vertebrate reveals distinct subcomplex dynamics in the peri-basal body pool. Peri-basal body IFT dynamics are not changed during cilia regeneration. Cytosolic microtubules are dispensable for IFT recruitment and retention in the peri-basal body pool.
Aspergillus nidulans biofilm formation modifies cellular architecture and enables light-activated autophagy
Authors: Lingo Dale E. , Shukla Nandini , Osmani Aysha H. , Osmani Stephen A.
Published: April 2021

Aspergillus nidulans biofilm formation promotes global changes to cell biology including modifications to the apparatus for exocytosis and endocytosis. Autophagy is also triggered during biofilm formation, which can be reactivated by spinning disc confocal light. These modifications likely impact the unique characteristics of fungal biofilm cells.
Cause-specific mortality prediction in older residents of São Paulo, Brazil: a machine learning approach
Authors: do Nascimento Carla Ferreira , dos Santos Hellen Geremias , de Moraes Batista André Filipe , Roman Lay Alejandra Andrea , Duarte Yeda Aparecida Oliveira , Chiavegatto Filho Alexandre Dias Porto
Published: April 2021

Background

Populational ageing has been increasing in a remarkable rate in developing countries. In this scenario, preventive strategies could help to decrease the burden of higher demands for healthcare services. Machine learning algorithms have been increasingly applied for identifying priority candidates for preventive actions, presenting a better predictive performance than traditional parsimonious models.

Methods

Data were collected from the Health, Well Being and Aging (SABE) Study, a representative sample of older residents of São Paulo, Brazil. Machine learning algorithms were applied to predict death by diseases of respiratory system (DRS), diseases of circulatory system (DCS), neoplasms and other specific causes within 5 years, using socioeconomic, demographic and health features. The algorithms were trained in a random sample of 70% of subjects, and then tested in the other 30% unseen data.

Results

The outcome with highest predictive performance was death by DRS (AUC−ROC = 0.89), followed by the other specific causes (AUC−ROC = 0.87), DCS (AUC−ROC = 0.67) and neoplasms (AUC−ROC = 0.52). Among only the 25% of individuals with the highest predicted risk of mortality from DRS were included 100% of the actual cases. The machine learning algorithms with the highest predictive performance were light gradient boosted machine and extreme gradient boosting.

Conclusion

The algorithms had a high predictive performance for DRS, but lower for DCS and neoplasms. Mortality prediction with machine learning can improve clinical decisions especially regarding targeted preventive measures for older individuals.
De Novo Identification and Visualization of Important Cell Populations for Classic Hodgkin Lymphoma Using Flow Cytometry and Machine Learning
Authors: Simonson Paul D , Wu Yue , Wu David , Fromm Jonathan R , Lee Aaron Y
Published: April 2021

Objectives

Automated classification of flow cytometry data has the potential to reduce errors and accelerate flow cytometry interpretation. We desired a machine learning approach that is accurate, is intuitively easy to understand, and highlights the cells that are most important in the algorithm’s prediction for a given case.

Methods

We developed an ensemble of convolutional neural networks for classification and visualization of impactful cell populations in detecting classic Hodgkin lymphoma using two-dimensional (2D) histograms. Data from 977 and 245 clinical flow cytometry cases were used for training and testing, respectively. Seventy-eight nongated 2D histograms were created per flow cytometry file. Shapley additive explanation (SHAP) values were calculated to determine the most impactful 2D histograms and regions within histograms. SHAP values from all 78 histograms were then projected back to the original cell data for gating and visualization using standard flow cytometry software.

Results

The algorithm achieved 67.7% recall (sensitivity), 82.4% precision, and 0.92 area under the receiver operating characteristic. Visualization of the important cell populations for individual predictions demonstrated correlations with known biology.

Conclusions

The method presented enables model explainability while highlighting important cell populations in individual flow cytometry specimens, with potential applications in both diagnosis and discovery of previously overlooked key cell populations.
Association of Overactive Bladder With Hypertension and Blood Pressure Control: The Multi-Ethnic Study of Atherosclerosis (MESA)
Authors: Akbar Aelia , Liu Kiang , Michos Erin D , Bancks Michael P , Brubaker Linda , Markossian Talar , Durazo-Arvizu Ramon , Kramer Holly
Published: April 2021

BACKGROUND

The sudden urge to urinate, also known as overactive bladder (OAB), may reflect higher sympathetic activity and associate with higher blood pressure (BP).

METHODS

This cross-sectional analysis utilized data from sixth follow-up exam (2015–2016) of Multi-Ethnic Study of Atherosclerosis to examine the association of OAB with systolic (SBP) and diastolic blood pressure (DBP) levels, hypertension, and BP control. Information on urinary symptoms was obtained with the International Consultation on Incontinence Questionnaire (ICIQ). Sex-stratified regression models were constructed to examine differences in BP, hypertension prevalence, and BP control while adjusting for demographic factors, comorbidities, and medication use.

RESULTS

Among the 1,446 men and 1,628 women who completed the ICIQ (mean age 73.7 years [SD 8.4]), OAB was present in 31.6% of men and 38.9% of women. With no antihypertensive medication use, OAB was not associated with SBP or DBP in both men and women after adjusting for covariates. However, among the 894 men and 981 women on antihypertensive medication, OAB was associated with higher SBP among men (4.04 mm Hg; 95% confidence interval [CI] 1.02, 7.06) but not among women (−0.67 mm Hg; 95% CI −3.79, 2.46) while DBP did not differ by OAB presence in men or women. In addition, OAB was also associated with lower odds of BP control among men (odds ratio [OR] 0.69; 95% CI 0.49, 0.96) but not women (OR 0.96; 95% CI 0.71, 1.30).

CONCLUSIONS

Among men, OAB is associated with lower odds of BP control which suggests that OAB may impede hypertension management.
Evidence of Browning of White Adipocytes in Poorly Survived Fat Grafts in Patients
Authors: Liu Tong , Fu Su , Wang Qian , Cheng Hao , Mu Dali , Luan Jie
Published: April 2021

Background

Browning adipocytes induced by burn and cancer were assumed less viable and more prone to necrosis for their hypermetabolic properties. Recent studies have shown browning of white adipose after fat engraftment in mice.

Objectives

The authors sought to evaluate whether fat transfer could induce browning biogenesis in fat grafts in humans and if it is associated with graft necrosis.

Methods

Necrotic adipose grafts were excised from 11 patients diagnosed with fat necrosis after fat grafting or flap transfer. Non-necrotic fat grafts were from 5 patients who underwent revisionary surgeries after flap transfer. Histology and electronic microscopy as well as protein and gene expression of browning-related marker analyses were performed.

Results

Fat grafts with necrosis demonstrated a higher gene expression level of uncoupling protein-1 (greater than fivefold increase, **P < 0.01), a master beige adipocyte marker, than non-necrotic fat grafts. Electronic microscopy and histology showed that browning adipocytes were presented in necrotic adipose in patients.

Conclusions

Fat transfer induced browning adipocytes in patients and was evident in patients with postgrafting necrosis.

Level of Evidence: 5
Metaphors as a Tool for Understanding of Lived Experience of Social Work Practitioners in the Contemporary Czech Society
Authors: Petrucijová Jelena , Glumbíková Kateřina
Published: April 2021

The paper aims to understand lived experience of social work practitioners in contemporary Czech society through the use of the potential of metaphors. Metaphors are seen as a tool for bringing implicit knowledge and experience to the surface (especially where they are encountered certain barriers to verbalisation); as an area of connecting lived experience and its essential meaning. Using the phenomenological hermeneutical method of thematic narrative analysis and structural thematic analysis of metaphorical narratives, new ways of structuring reality by participants and new coherences are revealed, thus re-describing reality that shows the tension, if not conflict, between the concept of social work based on technically conceived rationality as officially carried out and required institutional policy in social services and social work as a value-oriented profession The implication for social work: the social workers should reflect the impacts of the revealed conflict on the practice and reconsider the further role and development of social work.
Long-distance dispersal events rather than growth habit and life-history traits affect diversification rate in tribe Apieae (Apiaceae)
Authors: Frankiewicz Kamil E , Banasiak Łukasz , Oskolski Alexei , Reduron Jean-Pierre , Reyes-Betancort Jorge Alfredo , Alsarraf Mohammed , Trzeciak Paulina , Spalik Krzysztof
Published: April 2021

Factors influencing diversification rates may be of intrinsic (e.g. morphological novelties) or extrinsic (e.g. long-distance dispersal, availability of ecological niches) nature. Growth habit may influence diversification rates because herbaceous plants often have shorter generation times and a more pronounced r reproductive strategy than their woody relatives. We examined life history and habit evolution, wood anatomy and biogeographical history of Apiaceae tribe Apieae in conjunction with diversification rate analysis to explore which factors may have affected clade species richness and to elucidate the constraints on the evolution of secondary woodiness in this group. We demonstrate that diversification rates are similar in morphologically homogeneous and diverse clades and in herbaceous and woody lineages. The only clade with a significantly elevated diversification rate is Southern Hemisphere Apium, in which diversity probably resulted from several long-distance dispersal events. We also show that wood anatomy in herbaceous and woody species does not differ considerably regardless of their continental or insular origin, but it is affected by stem architecture and plant reproductive strategy. As the taxonomy of Apieae suffers from inflation with numerous monotypic genera, we propose to include Canaria in Rutheopsis, and Foeniculum, Schoenoselinum, Ridolfia and Pseudoridolfia in Anethum.