bluuebunny/crossref_metadata_2025 huggingface dataset:
Transient and steady-state temperature rise in three-dimensional anisotropic layered structures in pump-probe thermoreflectance experiments
Authors: Jiang Puqing , Ban Heng
Published: October 2020

Recent developments of the pump-probe thermoreflectance methods (such as the beam-offset and elliptical-beam approaches of the time-domain and frequency-domain thermoreflectance techniques) enabled measurements of the thermal conductivities of in-plane anisotropic materials. Estimating the temperature rise of anisotropic layered structures under surface heating is critically important to make sure that the temperature rise is not too high to alias the signals in these experiments. However, a simple formula to estimate the temperature rise in three-dimensional (3D) anisotropic layered systems heated by a non-circular laser beam is not available yet, which is the main problem we aim to solve in this work. We first re-derived general formalisms of the temperature rise of a multilayered structure based on the previous literature work by solving the 3D anisotropic heat diffusion equation in the frequency domain. These general formalisms normally require laborious numerical evaluation; however, they could be reduced to explicit analytical expressions for the case of semi-infinite solids. We then extend the analytical expressions to multilayered systems, taking into account the effect of the top layers. This work not only enhances our understanding of the physics of temperature rise due to surface laser heating but also enables quick estimation of the peak temperature rise of 3D anisotropic layered systems in pump-probe thermoreflectance experiments and thus greatly benefits the thermoreflectance experiments in choosing the appropriate heating power intensity for the experiments.
Fast electrical diagnostics and dispersion relation for ion density determination in an atmospheric pressure argon plasma
Authors: Gerling T , Wilke C , Becker M M
Published: October 2020

Investigations of an atmospheric pressure gas discharge in argon focusing on the experimental measurement of the ion density is presented. The suggested diagnostic method combines the evaluation of weak and erratically occurring oscillations of the current signal with the solution of the dispersion relation for the dominant ion species. The considered dispersion relation contains the contribution of electron and ion movement as well as collisions of ions with the neutral background gas. The solution is performed considering temporal decay and spatial damping, respectively, and shows the existence of an ion acoustic wave (IAW) despite atmospheric pressure conditions. A parameter variation when using the dispersion relation reveals a limited range of existence of an IAW depending strongly on the ion density and correlates with experimentally acquired values of the molecular argon ion density of about 1012 cm−3. Furthermore, the combination of the experimental investigations and the solution of the dispersion relation provides access to the molecular argon ion—neutral argon collision frequency with values of about 2×107 Hz and 6×107 Hz, respectively.
Broadband and high-efficiency ultrathin Pancharatnam-Berry metasurfaces for generating X-band orbital angular momentum beam
Authors: Gao Xi , Tang Liguang , Wu Xiongbin , Li Simin
Published: October 2020

Vortex beams have been extensively investigated for their major applications in wireless communications. To obtain practical applications, vortex beam generators with high performance and simple structure are of vital importance. Here, we present a novel metasurface-based device to generate high-performance vortex beams. This device is a four-layer Pancharatnam-Berry metasurface with ultrathin thickness. The unit cell of each metasurface is composed of a cross dipole and a square ring resonator. The simulated and experimental results show that the proposed meta-device can convert a right-hand circularly polarized wave into a left-hand circularly polarized vortex beam in a broadband from 9.3 to 12 GHz. Moreover, the device has high transmission efficiency up to 79% and ultrathin thickness of 0.2λ (λ is the central frequency of operation frequency band).
Vortex-lattice formation in a spin–orbit coupled rotating spin-1 condensate
Authors: Adhikari S K
Published: October 2020

We study the vortex-lattice formation in a rotating Rashba spin–orbit (SO) coupled quasi-two-dimensional (quasi-2D) hyper-fine spin-1 spinor Bose–Einstein condensate (BEC) in the x–y plane using a numerical solution of the underlying mean-field Gross–Pitaevskii equation. In this case, the non-rotating Rashba SO-coupled spinor BEC can have topological excitation in the form of vortices of different angular momenta in the three components, e.g. the (0, +1, +2)- and (−1, 0, +1)-type states in ferromagnetic and anti-ferromagnetic spinor BEC: the numbers in the parenthesis denote the intrinsic angular momentum of the vortex states of the three components with the negative sign denoting an anti-vortex. The presence of these states with intrinsic vorticity breaks the symmetry between rotation with vorticity along the z and −z axes and thus generates a rich variety of vortex-lattice and anti-vortex-lattice states in a rotating quasi-2D spin-1 spinor ferromagnetic and anti-ferromagnetic BEC, not possible in a scalar BEC. For weak SO coupling, we find two types of symmetries of these states − hexagonal and ‘square’. The hexagonal (square) symmetry state has vortices arranged in closed concentric orbits with a maximum of 6, 12, 18… (8, 12, 16…) vortices in successive orbits. Of these two symmetries, the square vortex-lattice state is found to have the smaller energy.
Indices for the evaluation of glandular dose heterogeneity in full-field digital mammography
Authors: Shinohara Sae , Araki Fujio , Maeda Megumi , Okamoto Rumi , Nakamura Mai , Higashida Yoshiharu
Published: October 2020

This study aims to evaluate the indices of glandular dose heterogeneity in full-field digital mammography. The distributions of GD in a breast phantom with a skin layer of 4 mm were determined using the Monte Carlo method with simulated x-ray fluence spectra. First, the GD to air kerma (GD/K
air) volume histogram was obtained from the GD distributions, which were indicated by the glandular volume (%) as a function of GD/K
air. The GD indices, namely, the maximum glandular dose (GD2%) and glandular volume percentage (%) receiving at least the mean glandular dose (MGD) (V
MGD) were calculated from the GD/K
air volume histogram. Next, the scatter plots of GD2%/MGD and V
MGD were drawn as functions of the normalised mean glandular dose (DgN). Finally, (GD2%)
i
and (V
MGD)
i
were obtained from the relationship between the GD indices and DgN for 596 clinical irradiation cases based on individual irradiation conditions. The values of GD2%/MGD were more affected by breast thickness than glandularity and tube voltage, and they decreased according to the power law of DgN for all the target/filter combinations. The values of V
MGD were proportional to DgN and decreased with increase in the compressed breast thickness. The values of (MGD)
i
and (GD2%)
i
for 596 clinical irradiation cases were estimated to range from 0.6–3.0 mGy to 1.1–7.0 mGy, respectively, and (V
MGD)
i
was in the range 32%−48%. (GD2%)
i
and (V
MGD)
i
are mainly affected by breast thickness. These indices are useful for the evaluation of glandular dose heterogeneity in mammography.
High-sensitivity and low-interference gas analyzer with feature extraction from mid-infrared laser absorption-modulated signal
Authors: Shibuya Kyoji , Podzorov Alexander , Matsuhama Makoto , Nishimura Katsumi , Magari Masaaki
Published: October 2020

In this paper, we propose a gas analyzer that uses a quantum cascade laser (QCL) and achieves high sensitivity and gas selectivity with simple configuration and signal processing. Feature quantities are extracted from an absorption-modulated signal, which is obtained by the logarithmic conversion of a detector signal receiving a wavelength-modulated laser light. The extracted feature quantities are used for the determination of target and interfering gas concentration with simple simultaneous linear equations. As a result of the demonstration of CO gas measurement with a gas analyzer consisting of a 4.6 μm pulsed QCL, a small-volume Herriott cell with a path length of 5 m and a thermopile as a photodetector, it is shown that the limit of detection is 2.0 ppb at the integration time of 1 s and that interference by N2O can be eliminated. It is also shown that various disturbances such as spectral shift due to laser wavelength drift and spectral broadening due to partial pressure change of coexisting gases can be corrected by extracting appropriate additional feature quantities.
Vehicle platform attitude estimation method based on adaptive Kalman filter and sliding window least squares
Authors: Luo Jun , Fan Yongkun , Jiang Ping , He Zijian , Xu Peng , Li Xin , Yang Wei , Zhou Wenlin , Ma Sen
Published: October 2020

Precision instrument measurement on an unstable platform is a difficult engineering problem, and the commonly used method is to compensate the instrument measurement results through platform attitude estimation. This paper derives a three-dimensional attitude estimation method based on inertial sensors including gyroscope and inclinometer. In order to deal with the inertial sensor noise, low-pass filter, Kalman filter, adaptive Kalman filter (AKF) and sliding window least squares (SWLS) are chosen to test the filtering performance from the frequency domain perspective. Practical filtering experiments indicate that AKF achieves the best filtering performance for gyroscope, while SWLS has the best filtering performance for inclinometer. Using AKF and SWLS to deal with inertial sensor outputs, the attitude estimation of the vehicle platform is realized. The proposed method is verified on vehicle-mounted electro-optical measurement equipment.
The nano-scale viscoelasticity using atomic force microscopy in liquid environment
Authors: Rajput Shatruhan Singh , Deopa Surya Pratap S , Yadav Jyoti , Ahlawat Vikhyaat , Talele Saurabh , Patil Shivprasad
Published: October 2020

We measured viscoelasticity of two nanoscale systems, single protein molecules and molecular layers of water confined between solid walls. In order to quantify the viscoelastic response of these nanoscale systems in liquid environment, the measurements are performed using two types of atomic force microscopes (AFMs), which employ different detection schemes to measure the cantilever response. We used a deflection detection scheme, available in commercial AFMs, that measures cantilever bending and a fibre-interferometer based detection which measures cantilever displacement. The hydrodynamics of the cantilever is modelled using Euler–Bernoulli equation with appropriate boundary conditions which accommodate both detection schemes. In a direct contradiction with many reports in the literature, the dissipation coefficient of a single octomer of titin I278 is found to be immeasurably low. The upper bound on the dissipation coefficient is 5 × 10−7 kg s−1, which is much lower than the reported values. The entropic stiffness of single unfolded domains of protein measured using both methods is in the range of 10 mN m−1. We show that in a conventional deflection detection measurement, the phase of the bending signal can be a primary source of artefacts in the dissipation estimates. It is recognized that the measurement of cantilever displacement, which has negligibly small phase lag due to hydrodynamics of the cantilever at low excitation frequencies, is better suited for ensuring artefact-free measurement of viscoelasticity compared to the measurement of the cantilever bending. Further, it was possible to measure dissipation in molecular layers of water confined between the tip and the substrate using fibre interferometer based AFM with similar experimental parameters. It confirms that the dissipation coefficient of a single I278 is below the detection limit of AFM. The results shed light on the discrepancy observed in the measured diffusional dynamics of protein collapse measured using Force spectroscopic techniques and single-molecule optical techniques.
Evaluation of continuous beam rescanning versus pulsed beam in pencil beam scanned proton therapy for lung tumours
Authors: Ribeiro Cássia O , Terpstra Jorvi , Janssens Guillaume , Langendijk Johannes A , Both Stefan , Muijs Christina T , Wijsman Robin , Knopf Antje , Meijers Arturs
Published: October 2020

The treatment of moving targets with pencil beam scanned proton therapy (PBS-PT) may rely on rescanning strategies to smooth out motion induced dosimetric disturbances. PBS-PT machines, such as Proteus®Plus (PPlus) and Proteus®One (POne), deliver a continuous or a pulsed beam, respectively. In PPlus, scaled (or no) rescanning can be applied, while POne implies intrinsic ‘rescanning’ due to its pulsed delivery. We investigated the efficacy of these PBS-PT delivery types for the treatment of lung tumours. In general, clinically acceptable plans were achieved, and PPlus and POne showed similar effectiveness.
Monte Carlo calculation of quality correction factors based on air kerma and absorbed dose to water in medium energy x-ray beams
Authors: Czarnecki Damian , Zink Klemens , Pimpinella Maria , Borbinha Jorge , Teles Pedro , Pinto Massimo
Published: October 2020

Clinical dosimetry is typically performed using ion chambers calibrated in terms of absorbed dose to water. As primary measurement standards for this quantity for low and medium energy x-rays are available only since a few years, most dosimetry protocols for this photon energy range are still based on air kerma calibration. For that reason, data for beam quality correction factors

k

Q
,

Q
0

, necessary for the application of dose to water based protocols, are scarce in literature. Currently the international IAEA TRS-398 Code of Practice is under revision and new

k

Q
,

Q
0

factors for a large number of ion chambers will be introduced in the update of this protocol. Several international groups provided the IAEA with experimental and Monte Carlo based data for this revision. Within the European Community the EURAMET 16NRM03 RTNORM project was initiated for that purpose. In the present study, Monte Carlo based results for the beam quality correction factors in medium energy x-ray beams for six ion chambers applying different Monte Carlo codes are presented. Additionally, the perturbation factor p

Q
, necessary for the calculation of dose to water from an air kerma calibration coefficient, was determined.

The beam quality correction factor

k

Q
,

Q
0

for the chambers varied in the investigated energy range by about 4%–5%, and for five out of six chambers the data could be fitted by a simple logarithmic function, if the half-value-layer was used as the beam quality specifier. Corresponding data using different Monte Carlo codes for the same ion chamber agreed within 0.5%. For the perturbation factor p

Q
, the data did not obey a comparable simple relationship with the beam quality specifier. The variation of p

Q
for all ion chambers was in the range of 3%–4%. Compared to recently published data, our p

Q
data is around 1% larger, although the same Monte Carlo code has been used. Compared to the latest experimental data, there are even deviations in the range of 2%.
MACACO II test-beam with high energy photons
Authors: Ros García A , Barrio J , Etxebeste A , García López J , Jiménez-Ramos M C , Lacasta C , Muñoz E , Oliver J F , Roser J , Llosá G
Published: October 2020

The IRIS group at IFIC Valencia is developing a three-layer Compton camera for treatment monitoring in proton therapy. The system is composed of three detector planes, each made of a

L
a
B

r
3

monolithic crystal coupled to a SiPM array. Having obtained successful results with the first prototype (MACACO) that demonstrated the feasibility of the proposed technology, a second prototype (MACACO II) with improved performance has been developed, and is the subject of this work. The new system has an enhanced detector energy resolution which translates into a higher spatial resolution of the telescope. The image reconstruction method has also been improved with an accurate model of the sensitivity matrix. The device has been tested with high energy photons at the National Accelerator Centre (CNA, Seville). The tests involved a proton beam of 18 MeV impinging on a graphite target, to produce 4.4 MeV photons. Data were taken at different system positions of the telescope with the first detector at 65 and 160 mm from the target, and at different beam intensities. The measurements allowed successful reconstruction of the photon emission distribution at two target positions separated by 5 mm in different telescope configurations. This result was obtained both with data recorded in the first and second telescope planes (two interaction events) and, for the first time in beam experiments, with data recorded in the three planes (three interaction events).
Particle-in-cell simulations of asymmetric reconnection driven by laser-powered capacitor coils
Authors: Huang Kai , Lu Quanming , Chien Abraham , Gao Lan , Ji Hantao , Wang Xueyi , Wang Shui
Published: October 2020

During magnetic reconnection, such as in the magnetopause of magnetized planets, the upstream plasma conditions between the two inflow regions are usually different. In this paper, we demonstrate that such a kind of asymmetric reconnection can be studied in the laboratory using the recently proposed experimental scheme where reconnection is driven by laser-powered capacitor coils. Two-dimensional particle-in-cell simulations on the

z
,
r

plane in a cylindrical coordinate are conducted to study magnetic reconnection with the inflow along the

r

direction. Magnetic reconnection is found to be asymmetric with a stronger magnetic field in the inner (small

r

) inflow region and a weaker magnetic field in the outer (large

r

) inflow region due to the cylindrical symmetric geometry. Electron crescent velocity distributions are observed near the flow stagnation point while ion crescent velocity distributions are observed in the region with Larmor electric field. The out-of-plane Hall magnetic field is asymmetric between the two inflow regions with a larger spatial scale in the outer inflow region. This asymmetric Hall magnetic field configuration is different from that in previous studies. The typical reconnection rate increases with a stronger driver and the highest rate is around 0.2

V
A

B
0

, where

B
0

is the typical value of the magnetic field and

V
A

is the Alfven speed. This study provides a new method to experimentally study asymmetric reconnection in the laboratory and has potential applications regarding magnetic reconnection in the magnetopause of magnetized planets.
Vertical 3D gallium nitride field-effect transistors based on fin structures with inverted p-doped channel
Authors: Strempel Klaas , Römer Friedhard , Yu Feng , Meneghini Matteo , Bakin Andrey , Wehmann Hergo-Heinrich , Witzigmann Bernd , Waag Andreas
Published: October 2020

This paper demonstrates the first vertical field-effect transistor based on gallium nitride (GaN) fin structures with an inverted p-doped channel layer. A top-down hybrid etching approach combining inductively coupled plasma reactive ion etching and KOH-based wet etching was applied to fabricate regular fields of GaN fins with smooth a-plane sidewalls. The obtained morphologies are explained using a cavity step-flow model. A 3D processing scheme has been developed and evaluated via focussed ion beam cross-sections. The top-down approach allows the introduction of arbitrary doping profiles along the channel without regrowth, enabling the modulation of the channel properties and thus increasing the flexibility of the device concept. Here, a vertical npn-doping profile was used to achieve normally-off operation with an increased threshold voltage as high as 2.65 V. The p-doped region and the 3D gate wrapped around the sidewalls create a very narrow vertical electron channel close to the interface between dielectric and semiconductor, resulting in good electrostatic gate control, low leakage currents through the inner fin core and high sensitivity to the interface between GaN and gate oxide. Hydrodynamic transport simulations were carried out and show good agreement with the performed current–voltage and capacitance–voltage measurements. The simulation indicates a reduced channel mobility which we attribute to interface scattering being particularly relevant in narrow channels. We also demonstrate the existence of oxide and interface traps with an estimated sheet density of 3.2 × 1012 cm−2 related to the Al2O3 gate dielectric causing an increased subthreshold swing. Thus, improving the interface quality is essential to reach the full potential of the presented vertical 3D transistor concept.
Mesoscopic quantum superposition states of weakly-coupled matter-wave solitons
Authors: Tsarev Dmitriy , Alodjants Alexander , Ngo The Vinh , Lee Ray-Kuang
Published: October 2020

The Josephson junctions (JJs) are at the heart of modern quantum technologies and metrology. In this work we establish quantum features of an atomic soliton Josephson junction (SJJ) device, which consists of two weakly-coupled condensates with negative scattering length. The condensates are trapped in a double-well potential and elongated in one dimension. Starting with classical field theory we map for the first time a two-soliton problem onto the effective two-mode Hamiltonian and perform a second quantization procedure. Compared to the conventional bosonic Josephson junction condensate system, we show that the SJJ-model in quantum domain exhibits unusual features due to its effective nonlinear strength proportional to the square of total particle number, N
2. A novel self-tuning effect for the effective tunneling parameter is also demonstrated in the SJJ-model, which depends on the particle number and rapidly vanishes as the JJ population imbalance increases. The formation of entangled Fock state superposition is predicted for the quantum SJJ-model, revealing dominant N00N-state components at the ‘edges’ for n = 0, N particle number. We have shown that the obtained quantum state is more resistant to few particle losses from the condensates if tiny components of entangled Fock states are present in the vicinity of the major N00N-state component. This peculiarity of the quantum SJJ-model establishes an important difference from its semiclassical analogue obtained in the framework of Hartree approach. Our results are confirmed by studying the first and N-order Hillery–Zubairy criteria applied for studying multiparticle entanglement and planar spin squeezing. The Einstein–Podolsky–Rosen quantum steering represents an important prerequisite for the crossover to the mesoscopic superposition Schrödinger-cat and/or N00N-states. The feasibility in observation for these predicted states of the SJJ-model in the experiments is also discussed by taking into account one- and three-body losses for lithium condensates.
Gibbs mixing of partially distinguishable photons with a polarising beamsplitter membrane
Authors: Holmes Zoë , Mintert Florian , Anders Janet
Published: October 2020

For a thought experiment concerning the mixing of two classical gases, Gibbs concluded that the work that can be extracted from mixing is determined by whether or not the gases can be distinguished by a semi-permeable membrane; that is, the mixing work is a discontinuous function of how similar the gases are. Here we describe an optomechanical setup that generalises Gibbs’ thought experiment to partially distinguishable quantum gases. Specifically, we model the interaction between a polarisation dependent beamsplitter, that plays the role of a semi-permeable membrane, and two photon gases of non-orthogonal polarisation. We find that the work arising from the mixing of the gases is related to the potential energy associated with the displacement of the microscopic membrane, and we derive a general quantum mixing work expression, valid for any two photon gases with the same number distribution. The quantum mixing work is found to change continuously with the distinguishability of the two polarised gases. In addition, fluctuations of the work on the microscopic membrane become important, which we calculate for Fock and thermal states of the photon gases. Our findings generalise Gibbs’ mixing to the quantum regime and open the door for new quantum thermodynamic (thought) experiments with quantum gases with non-orthogonal polarisations and microscopic pistons that can distinguish orthogonal polarisations.
Absorption imaging of trapped atoms in presence of AC-Stark shift
Authors: Bhardwaj Kavish , Ram S P , Singh S , Tiwari V B , Mishra S R
Published: October 2020

In this work, the effect of AC-Stark shift of atomic energy levels in an optical dipole trap (ODT) on in situ absorption imaging of the trapped atoms has been investigated. The Stark shift of various energy levels of 87Rb atoms relevant for trapping in the optical dipole trap (ODT) has been calculated. The spatially varying AC-Stark shift of energy levels due to ODT beam results in position dependent absorption cross-section of the atom at the absorption probe laser wavelength, which significantly modifies the measured optical density (OD) of the trapped atom cloud during the in situ absorption imaging. We have estimated the number of atoms trapped in the ODT taking AC-Stark shift into account. The estimated numbers are found to be higher at higher ODT beam power, making a qualitative agreement with larger trap depth at higher ODT beam power. This work can be particularly useful in estimating the in situ loss rate of atoms from the trap during the evaporative cooling of the trapped atom cloud.
Research on the Development of the Ubiquitous Power Internet of Things
Authors: Lidan Zhou , Zujia Cao , Gang Yao , Dong Liu
Published: October 2020

The dawn of the new century has witnessed the tremendous advancement of society. In response to the requirement of the progress of technologies and enterprise development, the Ubiquitous power Internet of things (UPIOT) is boosting to develop and playing a significant role in China’s power grid which not only connects all aspects of the power system, but also promotes the application and innovation of various new techniques. As time goes by, UPIOT has been the key part to realize the transformation of energy production and consumption which will achieve green and healthy progress of power grid. This paper analyses in detail the concept, main characteristics, construction goals and existing problems of the UPIOT. Besides, the key technologies that contain the big data, cloud computing, the internet of things, 5G, blockchain, artificial intelligence and other technologies are also proposed. Furthermore, this paper introduces different application scenarios of UPIOT and offers some suggestions to accelerate the development of UPIOT.
An Edge Computing Method for Partial Discharge under the Power Internet of Things
Authors: Wang Shaojing , Ren Maoxin , Cao Pei , Xu Peng
Published: October 2020

The recognition of impulse interference for the partial discharge data on the edge computing platform can effectively reduce the false alarm rate in the risk assessment of gas insulated switchgear (GIS). Therefore, an edge computing method for partial discharge is proposed in the paper, which uses the similarity computing among the aggregation of data for each sensor after clustering to match homologous signals. Finally, the algorithm will jointly locate the interference signal and recognize the impulse interference signal by comparing the received signal strength indicator (RSSI) of multiple UHF sensors in/out of GIS equipment. The training set, being consisted of partial discharge and interference signal from the test, is used to contrast the algorithms on the edge computing platform, the result of which indicates that the accuracy rate of the recognition of the impulse interference with the proposed algorithm is 81.4% on the computing platform, with the average processing time for each sample of 7.15s.
Research on System Architecture of Internet Data Center Construction in Substation based on Ubiquitous Function
Authors: Chen Zhang , Yan Zhangy , Jinhua Huang
Published: October 2020

Substation has the advantages of having spare area, close to users, rich communication resources, reliable power supply. By releasing substation site resources, data centers and cloud services can be provided to the society. Construction of Internet Data Center (IDC) with the idle substation resources to realize multi-station integration will economize on social costs and accelerate the development of the digital infrastructure. In this paper, we analysed the participants involved in the expansion data center of the substation. Explore relations among Grid Company, Telecom Operator and User. According to the time sequence of the development of multi-station fusion business, the business time sequence diagram of the substation extended data center station covering the whole business process was designed. Considering the business flow, information flow, and energy flow flows between each section, the dynamic sequence diagram was built. We build the system architecture of business implementation including construction, operation, settlement and other links.
Electricity Prediction under Edge Devices Based on Sparse Anomaly Perception
Authors: Yang Jun , Xu Aidong , Zeng Yonggang , Li Li Cheng , Jiang Yixin , Zhang Yunan , Wen Hong
Published: October 2020

Energy issues are closely related to human development. With the changes of the times and the rapid development of technology, power energy has become one of the indispensable energy in human social life, and is the most important part of energy field in modern society. Electricity prediction, as the basis for power system operation, optimization, and control, is facing new challenges in today’s rapidly evolving energy system environment. A large number of machine learning technology and deep learning technology have been applied to electricity prediction and achieved good results. In the edge computing environment, anomalous data collection is characterized by sparsity and time window, and machine learning regression algorithms are often affected by anomalous data. Electricity prediction under edge devices based on sparse anomaly perception is proposed, which combines the drop out idea and subsample idea to alleviate the above problems to some extent. And it can achieve faster training and more accurate prediction.
Study on Identification of Defect Types in XLPE Cable with Weibull Distribution
Authors: Duan Y B , Ma G Q , Zhang H , Hu X L , Li P F , Fu Y L , Chen Z L , Zhou Y W
Published: October 2020

In order to monitor the insulation condition of XLPE cables which have been one of the most popular equipment used in power transition, a method is proposed in this paper to identify the insulation defects accurately by analysing the Weibull distribution of partial discharge (PD) signals. Experiments were applied on a 10kV 30m XLPE cable and three typical types of insulation defect models were designed and tested. The discharge pulse signals of each defect model were collected and their Weibull parameters were analysed and estimated with the ordinary least square estimation method. Several common pattern recognition methods such as support vector machine (SVM), artificial neural network (ANN) as well as classification and regression tree (CART) were used to test the accuracy of the extracted Weibull parameters. The results verified that it is effective to use the parameters of Weibull distribution for defect identification of XLPE cables and the features are suitable for common pattern recognition models.
Solar Road Power Generation Assessment Based on Coupled Transportation and Power Distribution Systems
Authors: Wu Lingjie , Yuan Yue , Wu Han
Published: October 2020

The rising of energy demand together with environmental protection awareness have attracted worldwide interest in renewable energy, especially photovoltaic (PV). Meanwhile, with the expansion of transportation infrastructure, solar energy has been employed in roadway construction, called solar road. The technology of Solar road offers an opportunity to capture the vast and dispersed solar energy while maximizing the use of land. A PV power generation assessment method for solar road considering coupled distribution and transportation system is proposed in this paper. The dynamic shading caused by traffic flow on solar road is considered as an effect factor which will influence the PV output in the model. The proposed method is examined on a test system with a transportation and a radial distribution network. The numerical results substantiate that the proposed method is an effective tool for assessing the PV power generation of solar road.
Benefit Models and Optimization Clearing Model for Participants in Cloud Energy Storage
Authors: Wu Yanzheng , Zhu Junpeng , Yuan Yue
Published: October 2020

Energy storage can smooth the fluctuation of renewable energy sources and has the characteristic of flexibility, which makes it an important dispatching resource in distribution network. In order to promote the consumption of renewable energy sources and the reasonable configuration of energy storage resources, this paper expands the basic concept of cloud energy storage and puts forward an operation mechanism involving customers, distributed generation operators and the cloud energy storage operator. According to the commercial mode described, we analyze the benefits of the three parties, establish the opportunity cost model on the consumer side and the benefit models of the three parties. Then we propose the energy storage scheduling strategies, use an optimal scheduling model to solve the pricing and clearing problems of cloud energy storage and solve it with the multi-object searching algorithm based on particle swarm optimization algorithm. At last, the case study shows that the method proposed can effectively improve the overall benefits of cloud energy storage participants on the basis of satisfying the load demand of the customers and ensuring the profitability of distributed generation operators.
Meteorological droughts are projected to worsen in Central America’s dry corridor throughout the 21st century
Authors: Depsky Nicholas , Pons Diego
Published: October 2020

Understanding past and projected drought patterns across Central America’s ‘Dry Corridor’ (CADC) is crucial for adaptation planning and impact mitigation, especially in small-scale agricultural communities. We analyzed historical and predicted drought patterns in the CADC by calculating Standardized Precipitation Index (SPI) values from local rain gauge records, reanalysis data and a 20-member ensemble of bias-corrected, downscaled CMIP-5 GCMs at both seasonal (3 month) and annual (12 month) scales. Trends in drought frequency, duration, intensity were assessed for three, 30 year future periods compared to historical values. Our results suggest a decrease in mean annual rainfall of 8%–14% in the CADC under moderate to high emissions scenarios, respectively, by end-of-century (2071–2100) relative to a historical baseline (1950–2005). However, projected changes to drought characteristics under these scenarios are more pronounced, with seasonal-scale droughts projected to lengthen by 12%–30%, intensify by 17%–42% and increase in frequency by 21%–24% by end-of-century. Annual-scale, longer-term droughts are projected to lengthen by 68% under moderate emissions, potentially triple in length under high emissions and to intensify by 27%–74%. These results were similar yet slightly more pronounced for some drought metrics when just considering rainy/cropping season months (May–Oct). End-of-century changes to rainfall reliability and drought occurrence such as these would severely impact millions of vulnerable inhabitants in the CADC and should be considered in adaptation policymaking efforts.
City-size bias in knowledge on the effects of urban nature on people and biodiversity
Authors: Kendal Dave , Egerer Monika , Byrne Jason A , Jones Penelope J , Marsh Pauline , Threlfall Caragh G , Allegretto Gabriella , Kaplan Haylee , Nguyen Hanh K D , Pearson Sue , Wright Abigail , Flies Emily J
Published: October 2020

The evidence base for the benefits of urban nature for people and biodiversity is strong. However, cities are diverse and the social and environmental contexts of cities are likely to influence the observed effects of urban nature, and the application of evidence to differing contexts. To explore biases in the evidence base for the effects of urban nature, we text-matched city names in the abstracts and affiliations of 14 786 journal articles, from separate searches for articles on urban biodiversity, the health and wellbeing impacts of urban nature, and on urban ecosystem services. City names were found in 51% of article abstracts and 92% of affiliations. Most large cities were studied many times over, while only a small proportion of small cities were studied once or twice. Almost half the cities studied also had an author with an affiliation from that city. Most studies were from large developed cities, with relatively few studies from Africa and South America in particular. These biases mean the evidence base for the effects of urban nature on people and on biodiversity does not adequately represent the lived experience of the 41% of the world’s urban population who live in small cities, nor the residents of the many rapidly urbanising areas of the developing world. Care should be taken when extrapolating research findings from large global cities to smaller cities and cities in the developing world. Future research should encourage research design focussed on answering research questions rather than city selection by convenience, disentangle the role of city size from measures of urban intensity (such as population density or impervious surface cover), avoid gross urban-rural dualisms, and better contextualise existing research across social and environmental contexts.
Experimental Investigation of Fluid Flow Hydrodynamics in Porous Medium Pipeline
Authors: Liu Hongsheng , Wu Dan , Liu Lin
Published: October 2020

Porous medium square pipelines with pellet packed bed and cylindrical packed bed are employed to experimentally study the flow characteristics of water. Differences of flow characteristics between the pellet packed bed and cylindrical packed bed, as well as the circular pipe and the square pipe, are discussed by measuring the pipeline pressure drop under different flow rate, and the relationship between the pipe resistance coefficient and flow is analyzed. The results show that the pressure drop per unit length in the square pipe increases with the increase of flow rate and increases with the decrease of pellet diameter. The structure of large diameter pellet packed bed is more advantageous to form a relatively stable flow.
Spectral Filtering of Photovoltaic Cells Using Novel Bio-filter: Silver Coated Hibiscus Extract Using Ethanol Solution
Authors: Emetere M.E. , Adeyemo M.
Published: October 2020

The challenge of solar infrared radiation damage on the photovoltaic (PV) still subsists. This challenge has led to the low patronage of PV in the African solar market despite the purchasing price reduction. This research seeks to proffer solution to this challenge by shielding the surface of the PV panel from solar IR radiation. This solution is expected to also prolong the life span of the PV module. The bio-filter was synthesized using silver nitrate and hibiscus extract. The bio-filter was observed to have increased the current and power output in the polycrystalline panel by 1%. Also, it was observed that the bio-filter reduced the output in the monocrystalline by 2%. This result is adjudged promising as further research on other plant extracts are investigated.
Investigation of Biodegradable Optical filter in a Turbulent Solar Irradiation
Authors: Emetere M.E. , Rokosu A.K.
Published: October 2020

The damage of the solar cells in the photovoltaic (PV) module under harsh weather conditions is particularly an issue in tropical belt of Africa. The focus of this research is to investigate the role of the bio-filter on the PV module under harsh weather. It was discovered that the bio-filter narrows the voltage difference between the maximum and minimum voltages. This unique property of the bio-filter reduces the undulating excitations and de-excitations of electron in the PV module, thereby ensuring that the solar cells do not get damage. It is recommended that this experiment can be optimized via plant extraction techniques, doping techniques and doping concentration.
Experimental and Simulation Study of Thermal Performance of Amorphous Silicon Photovoltaic Double-skin Façade
Authors: Wang Z Y , Jiang P , He J J , Zhang W J , Ma S B
Published: October 2020

In order to study the thermal performance of amorphous silicon photovoltaic double-skin façade (a-Si PV DSF), the experimental cabin of a-Si PV DSF was designed and established in Nanjing, China (118.80° E, 32.06° N). The thermal performance of a-Si PV DSF was experimentally tested, and the influence of a-Si PV DSF on the heat gain of the cabin was studied. Using EnergyPlus to establish a simulation model of the experimental cabin, the model was verified by experimental data, and the verified model was used to simulate and analyze the heat transfer performance of a-Si PV DSF. The results show that a-Si PV DSF has better cooling and heat insulation effect during the day than at night, which can effectively reduce the heat gain of the external wall of the building. A-Si PV DSF has good energy-saving effect in different climate areas and reduce the heat gain of the external wall by more than 38%.
Analysis on the Operation of Ice Storage Air Conditioning System in Practical Engineering
Authors: Zhang M M , He M L , Wu Y X , Cao Z G , Zhang W J
Published: October 2020

Cold storage technology is one of the effective means to alleviate the imbalance of power load during peak and valley period. Based on a practical project, the operation of the ice storage air conditioning system was monitored for 26 days. Temperature, pressure, ice storage and other parameters were recorded. Through the analysis of the operation data and air temperature, it is found that the operation of the ice storage system is stable and consistent with the design condition. But there are still some shortcomings in the operating strategy. This paper provides some suggestions for the design and operation of air conditioning system in future projects.
The application of Jackfruit by-product on the development of healthy meat analogue
Authors: Hamid M A , Tsia F L C , Okit A A B , Xin C W , Cien H H , Harn L S , Patrick P N , Samirin S , Azizi W A A W , Irfanian A , Yee C F
Published: October 2020

This study is aimed to introduce the potential of jackfruit by-products to develop a healthy meat analogue. Meat analogue had been produced with different jackfruit by-products to wheat gluten ratio. The textural properties of meat analogs were studied, where the result showed a significant decrease in hardness and chewiness with decreasing wheat gluten content. In sensory properties, meat analogue with 58% jackfruit by-products and 20% vital wheat gluten was the most preferred meat analogue in terms of appearance, aroma, taste, color, hardness, juiciness and overall acceptability. Other than that, the nutritional composition of jackfruit by-products meat analogue showed higher content of protein and dietary fiber. It was concluded that jackfruit by-products were the new main ingredient to develop healthy meat analogue for vegetarians and health-conscious individuals who stick on meat-free or a reduced meat diet without jeopardizing protein and micronutrients intake.
Avocado seed waste utilization into biscuits as diabetes mellitus patients’ alternative foods
Authors: Ervianingsih  , Hurria  , astari C , Mursyid M , Kadir A R
Published: October 2020

Avocado seeds contain flavonoid compounds that can regulate blood sugar in people with diabetes by reducing glucose absorption and increasing insulin secretion. The purpose of this study is to use avocado seed waste into biscuits as an alternative food for people with diabetes. This research used an experimental method by using avocado seed flour active ingredients 0.98 g Kg / BW that met SNI standards. From the test results, the test is 3.93, the ash content test is 0.97, the fat content test is 21.3, the protein content test is 3.81, the carbohydrate content test is 70.16, and the calorie test is 485.49. these biscuits are made based on SNI standards.
Maltodextrin quality prepared from spoiled and leftover rice
Authors: Rahman A , Genisa J , Zainal
Published: October 2020

Rice is consumed by most people, especially in Asian countries. Rice consumption resulting left oever rice. Rice also has a low storability and resilience because it is susceptible to microorganisms. It will change to spoiled rice if leave it at room temperature. Both kinds of rice become mull. Hence, it required further processing of spoiled rice and leftover rice. One of the alternatives that can be done is by converting rice into maltodextrin. Maltodextrin is widely used in various industries including food, beverage, chemical and pharmaceutical industries. Similar to starch, maltodextrin is widely used as a thickener as well as an emulsifier. This research was conducted to determine the quality of matodextrin resulting from spoiled rice and leftover rice. Rice converted to maltodextrin by amylase enzyme and dried by using a spray dryer. The treatment is replicated 3 times and the data is statistically analyzed by using T-test. The parameters are water content, ash content, and color. The results showed that the water content of maltodextrin from spoiled rice was 1.6% and the leftover rice was 1.35%. In addition, the ash content resulted 0.37% and 0.48% for spoiled rice and leftover rice, respectively. The color test conducted using a chromameter shows that the brightness is suitable with the expected color of the maltodextrin.
Optimalization the temperature and time of soaking in instant rice making process
Authors: Rusdin I , Laga A , Pirman
Published: October 2020

Rice (Oryza sativa L.) as the staple food for the Indonesian population with average consumption level reaching more than 25.35 million tons per year. Rice grain is usually processed into rice and consumed as a staple food by most Indonesian people. The process of preparing rice is still relatively for the dynamic community, then preparation of instant rice will support preparing rice more shorter. The purpose of this research is to optimize the temperature and time of soaking in optimal water level at the gelatinization stage in instant rice making process. The research method was applied with various temperature of soaking (40, 50 and 60°C) and time of soaking (10, 20, 30, 40, 50 and 60 minutes). The parameter was observed the rice water level used oven method. The result was at 40°C temperature treatment, showed 37% average of water level. At the 50°C temperature, showed 38% average water level, and treatment with 60°C temperature, showed 39% average water level. The time of soaking ranges 10 to 60 minutes. The average of water level between 35% to 40%. The best temperature of soaking is 40°C in 10 minutes with a number of water level about 33%.