bluuebunny/crossref_metadata_2025 huggingface dataset:
Regenerative braking energy recovery control strategy for electric vehicles with battery temperature measurement
Authors: Tian Qin , Hao Cheng
Published: September 2023

Aiming at the problems of short mileage and overheating and easy damage of the battery in electric vehicles, the fuzzy control regenerative braking strategy with vehicle speed, braking intensity, battery state of charge (SOC), and the introduction of battery temperature as fuzzy control input and regenerative braking distribution percentage as output are proposed; secondly, the ideal braking force distribution curve and ECE regulations are used as the boundary to determine the braking force distribution range of pure electric vehicles. Finally, the control strategy designed in this paper is simulated under selected working conditions by ADVISOR software, and the effectiveness and superiority of this control strategy are verified. The strategy can not only reduce the damage to the battery caused by high temperatures but also obtain more braking energy.
Experimental investigation on heat transfer performance of the grooved spiral wound heat exchanger
Authors: Cao Jiaming , Wang Xuesheng , Chen Qinzhu
Published: September 2023

To enhance the heat transfer efficiency of the spiral wound heat exchanger, a grooved spiral wound heat exchanger (GSWHE) was proposed. A test platform was accomplished to experimentally investigate the heat transfer performance with the comparison of a spiral wound heat exchanger (SWHE). The uncertainty analysis of the experiment was conducted, with the maximum relative error being not more than ±5%. The comprehensive heat transfer coefficient of the GSWHE is higher than that of the SWHE when the cooling water flow rate is low. To determine the heat transfer coefficient of both sides, the Wilson plot method was applied. The tube side heat transfer coefficient in the SWHE is found to have an error of about ±30% compared to the empirical correlations. The results also clearly suggest that grooves enhance the heat transfer of the shell side in the GSWHE. By employing effectiveness as a criterion, the comprehensive performance of the GSWHE was found to be 1.23 times higher than that of the SWHE.
Optimization of Heat Dissipation and Control Scheme for Wind Turbine Gearbox Based on FloMaster-Simulink co-Simulation
Authors: Gui Xiangyu , Fu Xiaojing
Published: September 2023

Due to favorable wind conditions and steadily rising temperatures, the demand for heat dissipation for the gearbox of wind turbines rises every spring and summer, and the energy consumption of the heat dissipation system rises as well. In cases where the gearbox oil temperature is excessively high due to poor heat dissipation, the wind turbine unit may only operate at a limited load or shut down. This article suggests a restoration strategy that uses seawater to cool the gearbox lubrication system, based on the operation of the gearbox cooling system of wind turbines. The original wind turbine gearbox cooling system and the enhanced seawater cooling system simulation models are built at the same time, and dynamic working conditions simulation research is done by utilizing the FloMaster simulation platform. To achieve automatic management of the gearbox temperature, we alter the fan or pump’s speed by the oil temperature at the gearbox’s outlet. We design a control scheme based on the working principle and use the FloMaster-Simulink co-simulation to calculate the operating characteristics of the system under dynamic working conditions. The results show that by simultaneously controlling the speed of the pump and the speed of the fan, the cooling system has the best control effect and the lowest energy consumption, providing a reference for the development of the gearbox cooling system of wind turbines.
Parameter Optimization of Electric Pulse Deicer for Overhead Ground Wire Based on Finite Element Method
Authors: Huang Huan , Wu Jianrong , Jiang Tao , Lei Zhengfei , Peng Chi , Zhang Wei , Zhang Xun
Published: September 2023

Because it is difficult to implement short-circuit deicing, overhead ground wire deicing has always been a difficult problem in power grid ice prevention and disaster reduction. In this paper, the working principle of the overhead ground wire electric pulse deicing device is introduced. Then the electric pulse force calculation model of the overhead ground wire is established. The validity of the model is verified by comparing the model-calculated values of coil inductance and resistance with the experimentally measured values. The effect of coil turns, multiplier thickness, and the side length of the multiplier on the pulse force peak and impulse are analyzed. Finally, the electric pulse deicing test of the short-size ground wire is carried out in the artificial climate chamber. The results show that with the increase in the number of turns of the coil, the peak value of the pulse force decreases gradually, the impulse increases gradually, but the growth rate slows down. With the increase of the thickness of the multiplier, the peak value and impulse of the pulse force increase almost unchanged near the skin depth. With the increase of the side length of the multiplier, the peak value and impulse of the pulse force gradually increase until the area of the multiplier is close to the area of the coil. The electric pulse deicing test shows that the deicing length increases with the increase of the number of coil turns, and the deicing efficiency of the 60-turn coil deicing device is 90%.
Multi-Source Energy Storage Stations Control Strategy Considering Implicit Linearization of The Power Flow Manifold
Authors: Lou Ping , Shen Genqiang , Hu Yaojie , Yao Ying
Published: September 2023

With the development of distributed new energy and multi-type loads, in order to realize the effective management of distributed power sources by multi-microgrids and better play the supporting role of microgrids on distributed power sources, we consider the dynamic changes of power flow in the distribution network caused by the power interaction between multi-microgrids and shared energy storage and propose an optimal dispatching strategy of multi-microgrids considering multi-source synergy considering the constraints of power flow. Since the constraint of the distribution network is a highly nonlinear mixed integer programming problem with power terms, a linearized approximation model is adopted for the power flow of the distribution network, and then a multi-objective model with minimal wind power and photovoltaic abandonment and minimum total operating cost of multi-microgrid is established. The improved IEEE18 node system is used to verify the model, and the results show that the proposed method comprehensively considers the linkage of grid-load-storage, which makes the dispatching results more realistic and more applicable.
Influence of Micro Ribs Segment on Quasi-periodic Large-scale Vortex Structure in 4 Rod Bundle Lattices
Authors: Ma Songyang , Chen Wenzhen , Xiao Hongguang
Published: September 2023

Rod bundle lattices play a crucial role in nuclear reactors, steam generators, and heat exchangers. The inclusion of quasi-periodic large-scale vortex structures (QLVS) can enhance flow mixing between the channels of the rod bundle and improve the lattice’s heat transfer capability. To study the impact of micro-rib segments on flow and heat transfer in the lattice, the Reynolds stress model (RSM) is utilized. Results reveal that the arrangement of micro-ribs on the rod bundle surface promotes the generation of QLVSs. These micro-rib segments modify the flow field within the lattice, thereby influencing the QLVS. The drag coefficient and heat transfer coefficient of the rod bundle lattice with micro-rib segments show a positive correlation with the length of these segments compared with the standard rod bundle lattice.
Research on power grid energy saving and loss reduction control methods under the harmonic influence
Authors: Zhang Shujun , Lu Haiqing , Zhao Fei
Published: September 2023

To reduce energy consumption and power grid operation costs, a control method that considers the influence of harmonics is proposed for power grid energy saving and loss reduction. The zip load model is utilized to build the power grid load model, and voltage characteristic curves are obtained under different parameters to calculate network loss. Furthermore, the voltage RMS and total harmonic distortion of nodes are calculated under varying load levels. Ultimately, a control objective function is established to achieve power grid energy saving and loss reduction. Experimental results indicate that this method outperforms traditional methods in terms of voltage response effect and achieves a more extensive reduction range of network loss, with a maximum reduction exceeding 35%.
Two-stage dispatch optimal model of virtual power plant considering pumped storage
Authors: Wu MeiRong , Xue Fei , Ren Yong , Li Feng
Published: September 2023

When virtual power plant (VPP) participates in power grid dispatch, it not only faces the problem of market bidding but also has the security and stability problems of voltage, frequency, power flow, and so on. The optimal dispatch strategy of VPP, which participates in a hybrid market, is proposed. The two-stage optimal model is established. An economic dispatch optimal model based on robust control and stochastic linear programming is established to maximize the profit of VPP. Aiming to minimize the difference between the output power of each distribution energy resource and the optimal results of economic dispatch, a safety dispatch optimal model based on a particle swarm optimization algorithm is established. The simulation results with the measured data of the Ningxia power grid show that the two-stage optimal dispatch model is effective.
Active Disturbance Rejection Controll Strategy with Lead Compensation and Feedforward
Authors: Yuan Yecang , Ma Youjie , Zhou Xuesong , Zhang Jiangong , Wang Bo , Wen Quan , Wang Haocheng
Published: September 2023

An active disturbance rejection controll Strategy with lead compensation and feedforward (ADRC-LCF) is proposed to address the problem of poor power quality at the output of the direct-to-direct converter when the microgrid is subject to uncertain disturbances. The control strategy achieves the reconstruction of the self-anti-disturbance controller by connecting the over-compensator in series and introducing differential feedforward, which effectively improves the disturbance suppression performance of the controller. Finally, numerical simulations comparing different operating conditions show that the recovery time of the ADRC-LCF is reduced by about 70% and 58% compared to the PI and LADRC respectively in the face of load shedding; the maximum overshoot of the ADRC-LCF is reduced by about 81% and 58% compared to the PI and LADRC respectively in the face of a sudden increase in bus voltage.
A High Crosstalk Suppression SiC MOSFET Gate Driver
Authors: Wu Zhaohui , Chen Kangping , Li Bin
Published: September 2023

Fast switching speeds and high switching frequencies bring serious crosstalk problems in SiC MOSFET applications. In this paper, we design a SiC MOSFET gate driver with high crosstalk suppression capability by using a multi-level drive and active Miller clamp technology. In the design, an auxiliary branch is introduced to control the source potential of the SiC MOSFET to achieve multilevel driving. The branch has a simple structure, simple control logic, no external negative voltage supply, and adjustable negative output voltage. The proposed SiC MOSFET gate driver was designed using the Central Semiconductor Manufacturing Corporation (CSMC) 0.8 μm BCD high voltage process. The designed SiC MOSFET gate driver has an area of 2967 μm × 3180 μm. The simulation verification model is based on Wolfspeed’s SiC MOSFET product C3M0075120D. Post-layout simulation results show that a SiC MOSFET gate driver with a crosstalk suppression capability of over 150 V/ns is obtained, which can reliably drive SiC MOSFET power devices.
State Analysis of Protection Device Considering Primary Equipment
Authors: Zhang Hanbin , Liu Qing
Published: September 2023

At present, the state monitoring models of relay protection use constant fault probability to predict the failure rate of protection devices, fail to consider the dynamic impact of equipment aging on failure rate, and only analyze the status of protection devices. In view of this, an improved Markov state prediction method based on Weibull distribution is proposed, combining the primary equipment’s state space to analyze the state of the protection device. First, the failure model of the relay protection device is established by the GM-SVR method. Then the 13-state Markov chain is established by combining primary equipment and the protection device. Finally, after introducing the failure model, the prediction of the line protection operation state is realized. The simulation results show that the optimized Markov chain is more in line with the actual operating conditions and can more effectively predict the operating state of the equipment during the operating life.
Improving the Synchronous Stability Control Strategy of Virtual Synchronous Generators
Authors: Wang Liwei , Jiang Lin
Published: September 2023

The microgrid dominated by new energy has small inertia and weak damping, while a virtual synchronous generator (VSG) is an effective means to enhance inertia and damping to improve the stability of the microgrid. However, it also introduces power angle oscillation problems similar to that of synchronous machines. This paper is based on the current inner loop and voltage outer loop control of the three-phase LCL inverter. It introduces the virtual inertia and damping coefficient of the virtual synchronous generator, achieving a good grid connection effect. While a significant change in active power occurs, the system can lose synchronization and stability. Therefore, the paper proposes an improved synchronization stability control strategy for virtual synchronous generators by introducing a frequency-proportional integral feed-forward link in the reactive power loop to suppress power angle oscillation and improve system synchronization stability. Theoretical analysis was conducted on the synchronous stability of the improved control strategy in case of sudden changes in active power load. The effectiveness of the strategy was verified through simulation.
Wireless positioning method for transmission pipe gallery inspection robot based on the TDOA algorithm
Authors: Yao Wenjie , Zhang Hao , Luo Ruikai , Fu Jianding , Bai Wei , Zheng Pengwei , Wei Rongshan , Chen Zhizhong
Published: September 2023

A wireless sensor network for positioning an inspection robot is developed for a transmission pipe gallery environment. The time difference of the arrival algorithm optimized by the least squares method is utilized to realize the wireless positioning function of the robot in the inspection process. The developed system adopts a spiral configuration to install the sensor nodes at equal intervals on the sidewall of the transmission pipe gallery, and only 10 sensor nodes closest to the wireless signal transmission source are activated for each measurement, which avoids the poor long-distance measurement effect of the sensor, ensures sufficient accuracy, and reduces calculation costs. A wireless positioning simulation test was conducted in an experimental transmission corridor environment. The error of the simulation results is equivalent to the measurement error of a single sensor, and the error is not accumulated in the calculation of the algorithm, indicating that the algorithm has achieved good results.
Adaptive Power Control Method for Distributed Generators in DC Microgrids
Authors: Wang Xin , Yu Yangyang , Xi Shengzhe , Wang Lin , Yue Quanyou , Zhao Wei , Niu Zhiyong , Peng Peng
Published: September 2023

The model-free control strategy based on the adaptive observer is presented to manage load power distribution for distributed generators in DC microgrids. By dynamically linearizing the modeling of the microgrid system, the model-free secondary control signal is designed to coordinate the distributed power sources, so that the load power is distributed proportionally to the rated capacity. In addition, the desired output voltage is introduced to restore the system bus voltage. The control scheme cannot depend on the structural details of the object system, which is structurally simple and easily implemented. Finally, the feasibility of the proposed data-driven scheme is demonstrated through case test results based on the RTDS experimental platform.
Reliability analysis of wind power gearbox based on fault tree and monte carlo simulation
Authors: Chen Lin
Published: September 2023

The gearbox is an important speed-up component in wind turbine, and the environment in which wind turbine operates is generally harsh. For maintenance and replacement of the gearbox and its difficult operation, it is self-evident that it is important to ensure its reliable operation. Through collecting and analyzing the structural and functional principle of the gearbox and data of common failure modes, the fault tree of the gearbox is established, and failure rate data and corresponding distribution are obtained by manual and data inquiry for each bottom event. Combining Monte Carlo simulation, the reliability curves of each bottom event mode of the gearbox, the gearbox, and important components are solved, and the assumptions of improving the important bottom events are made. By comparing the curves with the previous ones, it is proved that the improvement of important components can effectively improve the system’s reliability.
Research on Decentralized Centralized Control Model for Fast Load Response
Authors: Fan Jinheng , Lu Yutao , Ma Zhenyu , Ma Li , Yu Zhiwen , Peng Weilun , Liu Qiying , Zhao Ying
Published: September 2023

With the introduction of a high proportion of new energy, the security and stability of the power system face enormous challenges. Against the backdrop of insufficient traditional flexible regulation resources, it is urgent to tap into the adjustable potential of load side rapid response resources. This article conducts a modeling of the dynamic response process of fast response load, and proposes a decentralized centralized control optimization model for fast response load in response to the demand of the power grid. Through simulation analysis of different examples, the optimization effect of this method on the load curve of the power system is obtained, achieving the suppression of new energy output fluctuations and the maintenance of real-time supply and demand balance in the power system.
Simulation analysis of cathodic ablation under the arcing action of vacuum rotary contacts
Authors: Liu Xiufeng , Cao Yundong , Fu Si
Published: September 2023

During the breaking process of the switchgear, a rotational movement of 1-10 degrees per millisecond is added to the contacts. Allowing for more even distribution of arc energy affects the cathodic ablation process. The cathode ablation process under the action of a vacuum rotary contact arc and the effect of rotary motion on the cathode surface are studied during arc ignition in a vacuum metal vapour arc in the paper. A three-dimensional (3D) cathodic ablation transient model with contact rotation characteristics is developed by considering the effects of arc pressure and the Marangoni effect, combined with the hydrodynamic equations and heat transfer equations. Based on a 3D transient model, the action of the arc on the cathode surface is compared and analyzed for different modes of contact movement. The results show that there is a lower cathode surface temperature, a smaller melt zone and a smaller ablation volume by the contact rotation method.
Experimental and Simulation Research on the Vibration Characteristics of the Traction Motor of Medium and Low Speed Maglev Train under Electromagnetic Excitation
Authors: Ou Fengyu , Chen Chunjun
Published: September 2023

In a medium and low speed maglev train, the linear induction motor (LIM) is employed as the traction motor, during operation its vibration characteristics correlate with the dynamic performance and noise radiation characteristics of the train. This paper conducted tests and established a three-dimensional simulation model of the LIM in a medium and low speed maglev train, to study the motor vibration characteristics by comparative analysis between test and simulation. The analysis results showed that the electromagnetic excitation sources of the train appear in the high-frequency band, with the main characteristic frequencies of 497.33 Hz, 994.33 Hz, 1989.00 Hz, and 3977.67 Hz. The structural modal analysis and vibration harmonic response analysis of the motor showed that the 3rd, 8th, and 18th modal frequencies of the motor structure approximate the frequencies of the electromagnetic excitation sources. As a result, the motor generates resonance at 497.33 Hz and 994.33 Hz under that excitation. The validity of the simulation was confirmed by the corresponding tests. From the perspective of theory, experiment, and simulation, this research can contribute to the optimization of traction systems in the future design of medium and low speed maglev trains.
Variable Flux Direct Torque Control System of Switched Reluctance Motor
Authors: Wu Shitao , Shen Chuanzhang , Xu Jiacheng
Published: September 2023

Direct Torque Control (DTC) strategy is very suitable for controlling Switched Reluctance Motors (SRM) due to its advantages of the simple control structure and fast system response, etc. This paper first analyzes the principle of DTC and establishes the DTC model of three-phase 6/4 SRM by Matlab/Simulink. In this paper, a three-closed-loop variable flux DTC system with velocity as the given quantity is constructed to solve the problem that the stator current of constant flux DTC is too large when the motor is in a steady state. The simulation results show that the variable flux DTC system has a better inhibition effect on the stator current and torque ripple of SRM than the conventional DTC system.
Consensus-based Distributed Bus Voltage Control of in DC Microgrid Clusters
Authors: Chen Ci , Zheng Min , Zhang Yajian , Peng Chen , Xue Fei
Published: September 2023

This paper proposes a consensus-based voltage control strategy for the bus of a DC microgrid cluster. Firstly, the closed-loop dynamics of a DC microgrid cluster bus voltage control system based on the consensus distributed control architecture is described, taking into full account the information exchange delay among the microgrid subsystems. Secondly, by constructing the Lyapunov-Krasovskii functional, the voltage control system asymptotic stability criteria under parameter uncertainties are rigorously derived, and the corresponding controller design criteria are obtained. Simulation results show that compared with the centralized control schemes, the proposed consensus distributed control method can reduce the average settling time by 24.39% and the average integral of absolute error of aggregate deviations by 23.92%.
Active disturbance rejection control of photovoltaic microgrids based on disturbance compensation and feed-forward correction strategy
Authors: Meng Shuqian , Xu Xiaoning , Wang Di
Published: September 2023

Photovoltaic microgrid (PV) is a promising direction of new energy generation technology. However, due to the performance of low-voltage side interface affected by complex disturbance, PV microgrid has the problem of output voltage fluctuation, which will make the power quality not guaranteed. In order to stabilize the low-voltage side load supply, the active disturbance rejection control strategy with disturbance compensation and feed-forward correction (ADRC-DCFC) is proposed. By expanding the conventional state observer (ESO) dimension, a feed-forward correction link for disturbance tracking compensation is added. In contrast, the internal deviations extracted from the system model are actively added to the disturbance compensation link. In addition, a theoretical analysis of its disturbance observation performance and noise suppression performance is presented. Experimental results on a 300-watt test platform verified the accuracy and effectiveness of the ADRC-DCFC.
An Optimization Approach for Distribution Network Planning Strategy Based on Combined Improved Cloud Model and Evidence Theory
Authors: Dong Fude , Liu Hanyu , Xu Yuantu , Zhu Deqiang , Huang Rongjie , Zou Haobin , Quan Huan , Peng Xiangang
Published: September 2023

With the continuous promotion of China’s power reform, higher requirements and standards have been put forward for distribution network investment decisions. However, the current work of distribution network project optimization in China has the problems of high subjectivity of investment decisions, fuzzy evaluation method, and high uncertainty of project optimization. In response to the above problems, this paper proposes a distribution network planning scheme optimization method based on the improved cloud model and evidence theory. Firstly, the optimal index system of the planning scheme is constructed from the dimensions of load transfer capacity, grid structure level, load capacity, investment benefit, social benefit, and life-cycle cost. Secondly, for subjectivity and ambiguity problems, the traditional degree of the membership function is replaced by a cloud model optimized by cloud entropy. Thirdly, the problem of uncertainty is addressed through evidence theory, while the game theory approach is used to identify conflicting evidence for evidence revision and fusion in the case of conflicting evidence arising from traditional evidence theory. Moreover, by improving the TOPSIS method and comparing the distances between the basic probability assignments of each planning scheme and the positive and negative virtual optimal solutions, the final decision results can be determined. Finally, the effectiveness and superiority of the proposed method are verified by experiments.
Design of Automatic Disconnection Device for Non-power Outage Operation of High-voltage Line
Authors: Yang Miao , Chen Wei , Li Jinliang , Wang Zoujun , You Kai , Li Zhe
Published: September 2023

A set of remote electric control disconnection device for high-voltage line with strong adaptability, easy operation, and high safety has been designed to address the problems of multiple spans, wide coverage, and difficulty in coordinating power failure with construction crossing operation. The design process aimed to reduce the weight and improve the reliability of the mechanical structure, and conducted computation and simulation of the traction force and safety load of the electrified tight cable. Based on the designed live disconnection device, experiments were conducted for different spans and cable diameters, while meeting the scope of infrastructure crossing sections. The experiments proved that the designed disconnection device has good effects in practical applications, and can select any point in the straight span to break the cable, in order to achieve safe and convenient uninterrupted operations in power recovery service.
Planning Method of Low-Voltage Distribution Network Applicable to the Access of Multiple Flexible Entities
Authors: Deng Yatuo , Xu Feifei , Fang Zhifa , Yang Jinwei , Yu Gaohan , Xu Qiao
Published: September 2023

Since the establishment of the goal of “peak carbon and carbon neutrality”, various types of emerging loads have been developing rapidly. However, the application scenarios and working principles of various loads are different, and there is no clear standard for distribution network requirements. Thus, the existing low-voltage distribution network planning methods do not take emerging loads into account. Therefore, this paper proposes a low-voltage distribution network planning method that is applicable to the access of multiple flexible subjects. Firstly, the operational characteristics of flexible resources on the power side, user side, and energy storage side are analyzed and studied. Secondly, the low-voltage distribution network planning method applicable to the access of multiple flexible subjects is studied. Finally, the low-voltage distribution network of Song Yang County, Lishui City, is selected for the empirical application.
The Noise of Rail Transport
Authors: Cavacece M
Published: September 2023

The research examines the sources of rail transport noise. Noise depends on the type of locomotives, warning signals, maintenance, and construction equipment. The wheel–to–rail contact of the rolling stock and the locomotives’ propulsion systems are the noise sources. Static and dynamic loads have intensities that depend on the masses and speeds of the trainsets. In addition, static, dynamic loads of the rolling stock, thermal loads, and the action of rainwater stress the ballast. The stresses lead to tensions on the rail that can affect fatigue, wear and tear, and railway line maintenance. Fatigue and wear are related to the intensity of traffic rail traffic, developing an abrasive action of the wheels on the rail and contributing to rail-to-rail misalignment concerning the underlying ballast.
Progress in microsphere-based scaffolds in bone/cartilage tissue engineering
Authors: Pan Qian , Su Weixian , Yao Yongchang
Published: September 2023

Bone/cartilage repair and regeneration have been popular and difficult issues in medical research. Tissue engineering is rapidly evolving to provide new solutions to this problem, and the key point is to design the appropriate scaffold biomaterial. In recent years, microsphere-based scaffolds have been considered suitable scaffold materials for bone/cartilage injury repair because microporous structures can form more internal space for better cell proliferation and other cellular activities, and these composite scaffolds can provide physical/chemical signals for neotissue formation with higher efficiency. This paper reviews the research progress of microsphere-based scaffolds in bone/chondral tissue engineering, briefly introduces types of microspheres made from polymer, inorganic and composite materials, discusses the preparation methods of microspheres and the exploration of suitable microsphere pore size in bone and cartilage tissue engineering, and finally details the application of microsphere-based scaffolds in biomimetic scaffolds, cell proliferation and drug delivery systems.
Relative magnetic helicity in multiply connected domains
Authors: MacTaggart David , Valli Alberto
Published: September 2023

Magnetic helicity is a conserved quantity of ideal magnetohydrodynamics (MHD) that is related to the topology of the magnetic field, and is widely studied in both laboratory and astrophysical plasmas. When the magnetic field has a non-trivial normal component on the boundary of the domain, the classical definition of helicity must be replaced by relative magnetic helicity. The purpose of this work is to review the various definitions of relative helicity and to show that they have a common origin—a general definition of relative helicity in multiply connected domains. We show that this general definition is both gauge-invariant and is conserved in time under ideal MHD, subject only to closed and line-tied boundary conditions. Other, more specific, formulae for relative helicity, that are used frequently in the literature, are shown to follow from the general expression by imposing extra conditions on the magnetic field or its vector potential.
Mammals diversity in Indonesian oil palm plantation: identifying its functional role in the agroecosystem
Authors: Kwatrina R T , Marsandi F , Fahmi S , Rianti A , Sihombing V S , Putri M M
Published: September 2023

The conventional profile of oil palm plantations that are not environmentally friendly, high-cost, and non-ecologically oriented, are not in line with sustainable development goals. There is a broad understanding of the role of mammalian species in the oil palm plantation landscape to create healthy oil palm plantations. To understand the functional role of these mammals, we identified various research over the last 10 years in Indonesia on mammals found in oil palm plantation landscapes through a systematic literature review approach. We use the Google Scholar search engine by entering search keywords and screening and analyzing the publications obtained. In the final stage, we analyze the possible use of mammals for production and ecological purposes. We found an increase in oil palm research in Indonesia over the last decade. Most of the research was conducted in large oil palm plantations, and the types of mammals found included large and small mammals, with the research focus on looking at the diversity and abundance of mammalian species, biodiversity loss and gain, as well as feeding guilds or tropic levels of mammalian species. The abundance of potential populations as pests is also a concern in several studies. Mammals in the context of contributing to production and ecology have a broad spectrum of roles, including various guild and tropic levels in the food chain, balancing ecosystems, pollinators, pest control, and other essential functions. We also focus on the gaps in research and management activities to achieve a healthy agroecosystem. The result can be served as a guide for future research priorities, conservation strategy, and management planning toward healthy oil plantations.
Bird diversity in the enrichment experiment plots of an oil palm plantation
Authors: Mulyani YA , Ikhsan TAN , Buchori D
Published: September 2023

Agricultural habitat heterogeneity could promote the bird biodiversity. Up to six native tree species had been planted in different plot sizes by the EFForTS (Ecological and Socioeconomic Functions of Tropical lowland rain forest transformation Systems) Project in Jambi Province, i.e., Petai (Parkia speciosa), Jengkol (Archidendron pauciflorum), Durian (Durio zibethinus), Sungkai (Peronema canescens), Meranti (Shorea leprosula) and Jelutung (Dyera polyphylla). This study is aimed to investigate the effect of native tree enrichment to bird diversity in oil palm plantation. Data was collected from 27 July to 10 August 2022 in enrichment experiment sites. The enrichment plots surveyed were those of 20 m x 20 m (13 plots) and 40 mx 40 m (12 plots) sizes. Point counts with a radius of 50 m were used to survey from 6.00 to 10.00, and, when necessary, from 15.30 to 17.30. A total of 33 bird species of 20 families were observed during the study, but only 24 species of 13 families were observed within the point count radius. Bird diversity was slightly higher in the larger enrichment plots (H’= 2.649; E= 0.845) than in the smaller plots (H’= 2.291; E= 0.826). Seven feedingguilds based on major dietwere identified, with the majority (48.5%) are insectivorous species. Two carnivorous species were recorded outside the point count radius, i.e.,Changeable Hawk-Eagle (Nisaetus cirrhatus) and Barn Owl (Tyto alba).
Potential and diversity of bird species in various land covers in PT BSM, South Sumatera
Authors: Masyithoh G , Kwatrina RT
Published: September 2023

Birds have an important role in the ecosystem, including as environmental indicators, natural pest controls, and tourist attractions. The existence of birds in a habitat type certainly plays an important role both ecologically and economically. Research that shows the ecological and economic potential of bird species in oil palm plantations is still not widely done. Therefore, research is needed to be able to show the potential and variation of bird species diversity in oil palm plantations. This research was conducted at PT Bina Sawit Makmur (PT BSM) on Desember 2019. The method used was a line transect that was carried out on five different land covers simultaneously. The results showed that a total of 28 species were found. High Conservation Value (HCV) land cover has the highest diversity, richness, and species similarity index values. The potential possessed by bird species in various types of land cover includes natural pest control, economic value animals, and environmental indicators.
The potential role of herpetofauna species diversity on palm oil agro-ecosystems: a case study in the plantation of PT BSM South Sumatra
Authors: Openg E B L
Published: September 2023

The palm oil industry is one of the national strategic industries that must gradually apply the concept of green economy where the use of biodiversity (to reduce the use of chemicals in increasing land fertility and controlling pests/diseases) should be optimized in various aspects of management. Therefore, the potential for species diversity and the role of biodiversity in palm oil agro-ecosystems needs to be investigated, one of which is herpetofauna diversity. Data collection on the diversity of herpetofauna species was carried out simultaneously on seven types of land cover for PT BSM’s palm oil plantations using the Visual Encounter Survey (VES) method. The results showed that the number of herpetofauna species varied according to land cover type with a total of 26 species. The highest number of species and individuals was found in shrubs (12 species and 18 individuals). While the lowest number of species and individuals was found in smallholder palm oil plantations 1 (5 species and 9 individuals). Based on the list of herpetofauna species in the study area, nine of these species have potential roles for the oil palm agro-ecosystem. These roles as biological control (predators, parasitoids, pathogens) include Takydromus sexlineatus, Eutropis multifasciata, Chalcorana chalconota, Occydoziga sumtrana, Malayopython reticulatus, Bungarus candidus, and Naja sumatrana, as well as decomposition controllers, Varanus salvator. The Shrubs land cover has a complete composisition of the roles of herpetofauna, while in the others land cover, have one individuals that play a role in the oil palm agroecosystem.
The role of plant species diversity in maintaining ecological balance in oil palm plantation
Authors: Nahlunnisa H , Kwatrina R T
Published: September 2023

The level of plant species diversity in oil palm plantations is thought to be decreasing in number. The existence of other plant species is considered to be a competitor for oil palm plants in obtaining water and plant nutrients. Thus, the diversity of plant species gets less attention because they are considered to have no role. We address this problem by analyzing the level of plant species diversity and the role of plant species diversity in maintaining the ecological balance in the plantation environment. This research was conducted on 4 types of landcover in TPR oil palm plantations (young growth, medium growth, old growth, HCV) and 2 smallholder oil palm plantations, by vegetation analysis with the single plot method. The results showed that the number of species on the research site was 49 species. The highest value of species richness and diversity was obtained in smallholder oil palm plantations (Dmg=3.11 and H′=2.18), while the highest evenness value was found in old growth (E=0.79). Based on the literature study, there were 23 species that have a direct ecological role in oil palm plantations. The ecological role of plants in oil palm plantations are as a ground cover for regulating soil moisture (4 species), producing litter for nutrient formation (5 species), fertilizing the soil and absorbing toxins (3 species), regulating water management and preventing erosion (3 species), increase soil carbon stocks and groundwater availability (2 species), animal feed (5 species), feed for wildlife (6 species), control pests and diseases (4 species), etc. The ecological role of this plant species will have a positive impact on oil palm plantations, especially in maintaining soil fertility, availability of groundwater, providing feed for animals, and also as biopesticides for oilpalm plants to avoid pests and diseases.
pH and temperatures optimation activity of crude chitinase of oil palm endophytic bacteria Bacillus cereus which have antagonistic properties on pathogenic fungi Ganoderma boninense
Authors: Mardiah I
Published: September 2023

Endophytic bacteria is promised solution to suppress basal stem rot disease caused by fungus Ganoderma boninense. The antifungal activities of selected isolate endophytic bacteria from oil palm plantation in South Kalimantan was studied. Bacillus cereus was tested for its antifungal activities of crude chitinase and secondary metabolites against the growth of Ganoderma boninense mycelium with dual cultured method. The results were showed that chitinase had the largest inhibition zone (18.5%) against growth inhibition of fungi Ganoderma boninense’s mycelium. A series of optimation assays of chitinase activity were conducted at pH 3 to 8 with 0.5 interval, and temperature at 30 to 70°C, with 5°C interval. Specific chitinase activities was measured using the colorimetric method. The highest specific chitinase activity significantly at 1.66393±0.04807 mU/μg (95% confidence level) at pH 5.5 and temperature 45°C.
Endophytic microbe in stem tissue of oil palm colonized by Ganoderma sp.
Authors: Widiastuti H , Permatasari G W , Taniwiryono D
Published: September 2023

Infection with Ganoderma sp. results in pseudoschlerotium, a distinctive feature of oil palm tissue trunks. The goal of this study was to study the microbial communities in Ganoderma sp. colonized oil palm trunk tissue. Endophytic bacteria are isolated from oil palm trunk tissue using selective media such as Ashby, Pikovskaya, King’s B, and a half-NA media to isolate N2 fixing bacteria, P solubilizing bacteria, Pseudomonas sp., and endophytic microbes, respectively. To prepare the sample, two methods were tested: 1) sterilizing the surface of the sample and then directly planting the stem tissue in a medium, and 2) sterilizing the surface of the tissue, crushing the tissue with a sterilizer mortar, and centrifuge for further seeding the supernatant in the selected medium. The first procedure was found to be effective in isolating N2-fixing bacteria from the top, middle, and bottom of the stem. We also recovered P solubilizing bacterium, which was yellow in colour and only located in the centre part of the stem, whereas the Pseudomonas sp. isolate was white in colour and found throughout the stem except at the bottom in the left side of the pseudosclerotium. We were able to isolate endophytic bacteria with a white hue using a half-NA medium. Method 2 did not succeed in isolating Azotobacter sp., but it can still isolate P solubilizing, Pseudomonas sp., and endophytic bacteria in all sections of the stem. The number of bacteria successfully isolated using the culture approach was low, particularly in the pseudosclerotium area. However, the larger quantity of Pseudomonas bacteria found in infected Ganoderma sp. tissue should be investigated further to establish the role of these bacteria, particularly in plant defence against Ganoderma sp.
Impact of chemical fertilizer on soil fertility of oil palm plantations in relation to productivity and environment
Authors: Azahari D H , Sukarman
Published: September 2023

Indonesia produces around 45 MT of CPO in 2020. It is predicted that the demand of world palm oil will remain. Most of the oil palm plantations are grown on acidic soils with low fertility levels, such as Peat soils, Podzolic soils, and Acid sulfate soils. The domestic demand of phosphate and Kalium fertilizer still fulfilled by importation. Production of oil palm had depend on this fertilizer. Various research results have found that fertilizing oil palm using chemical anorganic fertilizers, especially Urea, TSP, KCl and Kieserit, has produced fresh fruit bunches which are quite high and profitable. Fertilizing oil palm crops requires a very large cost of around 30% of production costs. Currently, non-subsidized chemical fertilizers are rocketing, which is very burdensome for oil palm farmers. Some research results indicate that the continuous use of chemical fertilizers in oil palm plants causes to the land degradation. The use of organic fertilizers can improve sour and less fertile land, can increase the weight and number of oil palm fruit bunches. This paper aims to examine the impact of the use of chemical fertilizers on oil palm fruit production, as well as provide alternative organic fertilizers which sources are mostly around plantations.
Maxent model application for conflict mitigation of Bornean Orangutan (Pongo pygmaeus wurmbii) in oil palm plantation
Authors: Risdiyanto I , Santosa Y , Santoso N , Sunkar A
Published: September 2023

The Bornean orangutan (Pongo pygmaeus wurmbii) is a flagship species and is protected by the Government of Indonesia and the global community. Orangutan habitat is in a tropical rainforest ecosystem. Orangutan exists in conservation area and development area (outside conservation). Development activities, such as oil palm plantations, cause fragmentation of orangutan habitat and triggers conflicts with humans. This study aims to map the suitability class of orangutan habitat and areas with potential conflicts around oil palm plantations and determine mitigation measures. The study site is located in Ketapang, West Kalimantan, Indonesia, consisting of forested areas and areas for development. This study uses the Maximum Entrophy (MaxEnt) model, which can simulate the probability of orangutans’ presence based on influencing environmental variables. Primary data is from 2019 – 2020 survey, and secondary data is collected from various sources. The study area is divided into three classes of orangutan habitat suitability: high, medium, and low. The dominant environmental variables in determining suitability classes are land use and land cover. The high and medium habitat suitability classes are mostly located in forested areas. The suitable habitat for orangutans in the study area is fragmented by community cultivation areas and oil palm plantations. Oil palm plantations are the variable with the highest contribution to the mapping of potential conflict vulnerabilities. The mitigation zone in the study area is divided into four zones. Zones 1, 2, and 3 can be linked by developing an orangutan corridor to connect with the nearby orangutan habitat in Gunung Palung National Park. Zone-1 is a Gunung Tarak Protected Forest, a buffer forest area for the Gunung Palung National Park. Zone-1 is the core orangutan conservation zone in the study area. This study suggests that oil palm companies in zones 1, 2, and 3 prioritize mitigation measures with passive preventive actions, while those in zone 4 can take active preventive mitigation actions.
Comparison of species diversity of mammals and herpetofauna between burnt and unburnt land after one year of fire in RAJ Oil Palm Estate, South Sumatera
Authors: Masy’ud B , Ginoga L N , Aulia N , Gusnadi F D
Published: September 2023

Frequent fires are common in Indonesia, particularly within oil palm plantations, and are believed to negatively affect the diversity of native plants and animals. In 2018, the RAJ oil palm plantation in South Sumatra experienced a fire incident. This study aimed to assess the contrasting diversity of mammal and herpetofauna species and the impact of fire on species abundance over one year. Data were collected in burnt and unburnt areas with two land cover types, grass and gelam. Transect strips, 1 km long and 50 m wide, were established in each land cover for mammal observations, while the Visual Encounter Survey (VES) method was used for herpetofauna. Data were collected during active animal hours: 06:00-08:00 and 16:00-18:00 for mammals, and 19:00-21:00 for herpetofauna, with three observation rounds each. The analysis included number of eah species, species richness and evenness indices, community similarity index, and percentage of species loss and gain. Results revealed 5 mammal and 5 herpetofauna species in both land cover types. Species Diversity (H′) and Richness (Dmg) Indices differed for each animal group. Generally, H′ and Dmg were higher in burnt areas for mammals, while for herpetofauna, values were greater in unburnt land. Mammal species loss was lower than in burnt areas, with 20% loss and 60% gain in grassland, and 33% loss and gain in gelam land. Herpetofauna loss and gain percentages were similar in unburnt and burnt lands, at 20% for grassland and 33% for gelam land.