bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental study of core MHD events in thousand-second improved confinement plasma on the EAST tokamak
Authors: Xu Liqing , Chu Yuqi , Lin Shiyao , Li Erzhong , Zhou Tianfu , Mai Chaowei , Huang Yueheng , Zang Qing , Zhang Bin , Wang Shouxin , Qian Jinping , Chao Yan , Duan Yanmin , Hu Liqun , Huang Yao , Liu Haiqing , Gong Xianzu , Song Yuntao
Published: April 2023

Recently, stationary plasma with a world-record pulse length of 1056 s was achieved on the Experimental Advanced Superconducting Tokamak (EAST). In this work, the core magnetohydrodynamics (MHD) events as well as mode coupling processes have been investigated in EAST long pulse operation with electron heating dominant and pure radio frequency wave heating low collisionality, by using several diagnostics and the nonlinear numerical code M3D together. A saturated m/n = 1/1 kink mode was observed in the core region, where a stable internal transport barrier was found in the electron temperature channel. The frequencies and 2D structures of these modes were studied by a combination of soft X-ray (SXR) imaging and electron cyclotron emission diagnostics. The frequency of the m/n = 1/1 mode exhibited a feature of chirping down with time, and this chirping rate corresponds to the rate of electron diamagnetic drift frequency change. A twisted pattern (‘Taichi structure in shape’) was reconstructed by SXR tomography of the m/n = 1/1 mode. The perturbations of electron temperature and density caused by m/n = 1/1 are different in size, the latter one being much smaller. The destabilization of m/n = 1/1 was due to the strong central heating combined with electron cyclotron resonance heating and lower hybrid current drive. In the presence of the m/n = 1/1 mode, a negative current was generated on the magnetic axis, which anomalously broadened the core current profile. A m/n = 3/2 tearing mode triggered by m/n = 1/1 mode was also observed. The m/n = 3/2 mode has a smaller frequency than the m/n = 1/1 mode, and carries an m/n = 3/2 island with detectable size. A novel 3D MHD model that separately evolves the plasma density and temperature is applied to the m/n = 3/2 triggered by m/n = 1/1. It is found that a toroidal current density at the q = 1.5 surface, caused by non-axisymmetric density perturbation during the m/n = 1/1 nonlinear growth phase, was generated and hence the destabilization of the m/n = 3/2 tearing mode. Both the modeled electron temperature and density perturbations agree well with experimental observations. In the last section of this paper, the interaction between the m/n = 1/1 mode and fast electrons as well as the active control of this mode are also presented.
Research on active power filter technology
Authors: Zou Xianzheng , Sheng Yifa , Jiang Yiran
Published: April 2023

A large number of power electronic devices used and transformed for the electrical energy in the grid has improved the characteristics and economic efficiency of the utility grid of the power system, but the nonlinear load components make the harmonic pollution in the grid more and more serious, which reduces the power quality of the power supply network. An active filter model based on ip-iq algorithm and PI control strategy is proposed and simulated to show that the filter can compensate for reactive power factor and harmonics and effectively suppress harmonics.
Study on Vibration Characteristics of Transformer Winding
Authors: Duan Minghui , Ma Hao , Wei Jufang , Liu Liqing , Ma Xiaoguang , Yao Chuang , Feng Junji , Zhang He
Published: April 2023

Compared with the existing winding deformation detection technologies, such as the frequency response method and short-circuit reactance, the vibration analysis method can effectively detect the loose state of windings. This paper has carried out mechanism analysis and experimental study on the change of winding modal characteristics caused by two kinds of defects, analyzed the transmission characteristics of three-phase double winding transformer winding vibration in the transformer oil and structure, studied the influence of pad falling off, plastic deformation and other defects on the mechanical state of the winding, calculated the winding short-circuit vibration signals corresponding to different mechanical states, and extracted the vibration characteristics that can effectively reflect the mechanical state of the winding. The research conclusion can provide an important basis for transformer fault diagnosis.
Health status assessment of large complex equipment based on matter-element analysis of equipment historical service environment information
Authors: Guo Ming , Wu Fei , Li Biao , Zhu Min
Published: April 2023

As the level of basic manufacturing increases, large complex equipment often has a high reliability level, leading to a lack of failure data and a more difficult health status assessment. Equipment history service environment information is the natural environment in which the equipment is located, which has an important impact on the health status of the equipment. This paper proposes a method for evaluating the health status of large complex equipment based on a matter-element analysis model using equipment historical service environment information. It can integrate statistically obtainable environmental information, such as temperature and humidity, with non-statistically obtainable environmental information, such as salt spray and random shock, and jointly achieve a quantitative evaluation of the health status of the equipment. The evaluation results show that the method can better integrate the influence of incompatible environmental indicators on the health status of equipment, which is of great significance for making scientific and reasonable decisions on the maintenance of large complex equipment.
Boiling Heat Transfer Coefficients of R290 in Tubes
Authors: Ni Fengbing
Published: April 2023

In 2016, Montreal Protocol Kigali Amendment stipulated that developed countries should reduce the consumption and production of HFCs from 2019 and that developing countries should start the reduction in 2029. New alternative refrigerants should have lower GWP to reduce negative effects on the environment. Propane (R290) is an efficient and clean energy fuel. It not only has a high calorific value, but also has the advantages of large reserves and light weight. However, it has high flammability, so it has not been applied in production extensively. Therefore, despite the possible applications for propane as a refrigerant, a limited quantity of heat transfer information can be found in the open literature. In this study, the boiling heat transfer of R290 in 1.5, 4.0 and 6.0 mm smooth tubes was experimentally studied in the existing literature, and draws some conclusions with the usage of comparative analysis method.
Design and Analysis of the Mechanical Structure of Land-Air Logistics UAV
Authors: Luo Jianfeng , Xiong Jiajie , Feng Tao , Zhang Lei
Published: April 2023

In the post-epidemic era, drone distribution has attracted increasing public attention because of its excellent contact-free characteristics and capacity to greatly improve the efficiency and reliability of material distribution. Combining land-air drones with logistics distribution, this design breaks through the limitations of the single-movement ability of traditional drones and land robots to fly in the air or move on the ground. Based on the collection and statistics of technical indicators related to logistics distribution, this paper focuses on the design of land-air conversion mode, and proposes an innovative land-air conversion mechanism composed of ball screw nut pair and multiple sets of gears to complete the design of the related mechanical structure of land-air logistics UAV. In addition, the mechanical system simulation of drones is carried out by ADAMS software. Moreover, the static and aerodynamic simulation analysis of UAVs is conducted by ANSYS software to optimize the overall structure.
Grounding Protection of flexible grounding systems Based on Polarization of Faulty Phase Voltage
Authors: Liu Xiao , Liu Cuicui
Published: April 2023

At present, the grounding protection of flexible grounding systems mostly follows the common protection methods of the low-resistance grounding system, and there are problems of insufficient adaptability and utilization of fault information. In the paper, We analyze the fault characteristics of flexible grounding systems after grounding faults, find that when a high-impedance grounding fault happened, after the low-resistance is connected to the Petersen Coil, the phase characteristics between the zero-sequence of voltage and current of flexible grounding system is similar to that of low-resistance grounding system when grounding faults happened, at this time the faulty phase voltage amplitude is far more than the zero sequence voltage and the phases of the two are opposite. Based on this, a flexible grounding system grounding fault location method using the phase relation between zero sequence current of lines and faulty phase voltage is proposed. By taking advantage of the mature phase selection technology of the resonant grounding system, selecting the faulty phase in the compensation stage of the Petersen Coil. When the low-resistance is in parallel, the faulty phase voltage is used to compare the phase with the zero sequence current of lines, which solves the problem that the zero sequence voltage is weak and difficult to measure when the high impedance grounding fault occurs. Simulation experiments and field tests show that this method can improve the reliability of high-impedance grounding protection, and the method can be used as a backup protection for zero sequence overcurrent protection to meet field requirements.
Design of Seafood Freshness Detector based on Trimethylamine Gas Measurement
Authors: Wu Haiqin , Liu Huimin , Xing Delong , Li Fang , Chen Qiuyue , Jiang Weilong
Published: April 2023

Food safety has become an important concern to people’s healthy life, the project is based on the TGS2603 gas sensor module, a minimum STM32 microcontroller system, and release of food trimethylamine gas sensitive quick measurement, as a basis for judging the freshness of food. The device is minimized by integration to realize real-time detection of data, and the freshness of food is presented as a simple and clear data prompt. The design scheme has been tested and verified by the prototype, and the performance indexes meet the design functions and requirements, providing maximum convenience for difficult people who cannot judge whether the seafood is fresh or not.
Research on Transformer Equipment Identification Based on Improved Fast RCNN Algorithm
Authors: Liao Xiaohui , Liu Shanlu , Wang Yuhan , Cai Zhilong
Published: April 2023

Because of the problems such as the long work cycle and manual efficiency faced by the traditional manual inspection and video monitoring inspection methods of substations, this paper proposes an electrical equipment identification algorithm that improves the Fast RCNN network to realize automatic identification and positioning of electrical equipment. We used affine transformation, background fusion, hue and saturation change, clipping and filling methods to enrich images and change the feature extraction network from VGG16 to ResNet50 with residual structure so that the feature extraction network can focus on specific anchor frames, and then used K-means clustering algorithm in the regional recommendation network to increase the convergence speed of the model, in this way, the improved anchoring height-to-width ratio is more suitable for detecting the image of power equipment. The experimental simulation shows that the average detection accuracy of the improved model is better than that of the original model, with the average accuracy mAP reaching 90.04%, and the image detection speed reaching 11 frames/second.
Characteristics and Applicability of Line Selection of Non-solidly Grounding Fault in Paralleling Double-Circuit Distribution Lines on Different Buses
Authors: Gong Huichang , Sun Rongke
Published: April 2023

To improve power supply capacity and save land resources, a large number of single-circuit distribution lines have been transformed into double-circuit distribution lines. The influence of their complex coupling relationship on the characteristics of non-solidly grounding faults and the applicability of existing line selection methods are not yet clear. An equivalent model of small grounding fault in double-circuit line from different buses is established, and the influence of the line-to-line coupling on the fault characteristics of the grounding system and the applicability of the line selection methods are analyzed by it. The results show that: for the system with a grounding fault, the line-to-line coupling does not affect its zero-sequence voltage and current characteristics, and the existing line selection methods are still applicable; for the system without a grounding fault, the double-circuit line shows the characteristics of the faulty line, and the existing line selection methods are no longer applicable. Simulation is used to verify the results.
Design and research of feed switching system for 40m radio telescope
Authors: Yang Feng-hui , Wang Min , Dong Liang , Shi Shuo-biao
Published: April 2023

For a large-aperture radio telescope, the working frequency of the feed and receiver determines its working range and capability. Many telescopes are designed with relatively few feed sources. With the development of deep space explorations and astronomical technologies, the existing feed of the antenna cannot meet the needs of observation tasks. To further adapt to the needs of the lunar exploration project, deep space explorations, and other astronomical observations, the feed of the 40 m antenna was upgraded with multiple feeds and feed switching systems. Based on not changing the existing antenna structure, the original S/X dual band feed is removed, a new S/X dual band feed is installed, C band and Ku band feeds are added, and rapid electrical switching of three feeds was realized. This paper gives a detailed design scheme and an implementation scheme of the feed-switching system. After being upgraded, the performance indexes of the antenna meet requirements, and the 40m telescope has multi-band reception capability, which lays a foundation for making the best of the telescope and making more scientific research outputs.
Multi-Sensor Fusion Tomato Picking Robot Localization and Mapping Research
Authors: Chen Kai , Yang Jian , Jiang Shuai , Xiong Chuan
Published: April 2023

To address the current problem of unsatisfactory localization and map building of an intelligent picking robot mobile platform in an unstructured picking environment, a multi-sensor fusion localization and map building method is proposed to fuse the visual odometer position estimation results with IMU and wheel odometer. And the pre-fusion processing of wheel odometer data is proposed to solve the problem of large errors of wheel odometers on uneven ground. The multi-sensor fusion scheme is proposed to fuse vision and laser SLAM methods to build a more information-rich point cloud and raster fusion map for the problem of non-closure caused by sparse branches. The experimental results show that the multi-sensor fusion SLAM method can obtain more accurate, richer, and more robust maps.
Research of Continuous Delta-Sigma Analog-to-Digital Converter for Bio-Electricity Signal Acquisition
Authors: Li L W , Sun J
Published: April 2023

In this paper, a continuous delta-sigma analog-to-digital converter with a low power, single-ring, third-order mixed integrator for bio-electricity signal acquisition is proposed. For the trade-off between low power consumption and high resolution, the Active-RC integrator is used in the first-order of the third-order feedforward modulator and the Gm-C integrator with improved linearity is adopted for the second and third order integrators. Because of the infinite resistance provided by the Gm-C integrator, the first-order integrator can replace the traditional second-order operational transconductance amplifier (OTA) with a single-stage OTA operating in the weak invert region to achieve low power consumption and ensure the output swing of the first-order integrator. The structure of cascade-of-integrators with feedforward (CIFF) can scale the output voltage values of three integrators and reduce the requirement of linearity of the Gm-C integrator, to reduce the design difficulty of the Gm-C integrator. In addition, the linearity of the second and third-order Gm-C integrator is improved by using the auxiliary difference pair OTA with source-level negative feedback. Therefore, the matching between the circuit structure and the model coefficients is improved significantly.
Operation Optimization Study of Integrated Energy System with Electric and Thermal Coupling Characteristics
Authors: Zhang Min , Fan Rui , Wang Jinhao , Zhi Huiqiang , Chang Xiao
Published: April 2023

The differences in inertia effects on multiple energy sources cause an imbalance between energy supply and load demand. Therefore, an operation optimization method for a comprehensive energy system with electric and thermal coupling characteristics is proposed. This method adopts the thermal system to reduce the system operation cost and improve operational reliability. Firstly, the method takes the energy transmission network of IES as the basis and establishes the model of the heating pipeline. Secondly, the method also takes the lowest total operating cost of the system as the goal, combines the power balance and equipment operation safety and other constraints, considers the electro-thermal coupling characteristics, establishes the corresponding IES operation optimization model, and applies the genetic algorithm to solve it. Finally, the simulation results show that the method can effectively reduce the system operation cost while ensuring the smooth and safe operation of the equipment based on the optimization model.
Based on MOPSO Algorithm of Real-Time Traffic Signal Optimization Control for Intelligent Transportation Intersections
Authors: Guo Jinwei , Huang Xiaoyan , Li Ran , Li Ziyan , Sun Ning , Dong Haibo
Published: April 2023

In order to improve the traffic efficiency of intersections, this paper establishes a multi-objective optimization model with the minimum real-time delay time and maximum capacity as the optimization objectives by applying multi-objective particle swarm optimization algorithm, and simulates the actual intersections. By optimizing the multi-objective model, a set of Pareto optimal solution sets can be obtained, and the optimal timing scheme can be determined by using multi-attribute decision-making algorithm and real-time update of signal timing configuration parameters to achieve dynamic optimization of signal timing. The simulation model of city road intersection is established by SUMO software. By using multi-objective particle swarm optimization algorithm to optimize the intersection simulation model, the traffic capacity of the simulated intersection has been greatly improved, with the average traffic capacity increasing by about 3.69% and the average vehicle delay time decreasing by about 21.35%.
Research on the current control method of PMSM based on the improved sliding mode controller
Authors: Chen Ziyi , Chen Guochu
Published: April 2023

Times are changing with each passing day, and permanent magnet synchronous motors are becoming popular in the new energy industry on account of its power consumption conversion rate is the same, its pollution is relatively small. For the problems of Buffeting and error when the system reaches stability vector control of PMSM, paper researches and tenders a kind of vector control based on a double power sliding mode permanent magnet motor. First, the traditional PI controller is replaced by a modified convergence-law sliding mode control in the current loop to improve overshoot and sliding mode jitter, new system stability is determined using Lyapunov function. Finally, simulation system in MATLAB/simulink is built, and the double-power sliding mode approach law, common sliding mode approach law, and PI control are compared and verified, and the waveforms of the three methods are compared.

Paper, method of double power reaching law is used to track and control the current loop, the innovation point is that the double exponential law of approach, its advantage in (1) compared with other general convergence speed law of approach of sliding mode control(SMC) for faster relative to the general SMC (2) the steady-state error is smaller, effectively prevent the chattering.
Reconfiguration Incremental Control Allocation for Tailless Aerial Vehicle with Control Surface Faults
Authors: Su Maoyu , Hu Jianbo , Wang Yingyang , Cong Jiping
Published: April 2023

To address the faults of the tailless aerial vehicle control surface with nonlinear control effectiveness, a reconfiguration incremental control allocation method is proposed. Under the framework of incremental control allocation, four types of typical control surface faults, such as floating, jamming, damaged, and median offset, are modeled. The isolation of faulty control surfaces and the reconfiguration of the flight control system is realized by adjusting the control surface deflection increment limit and changing the local control effectiveness matrix. The results show that the method can effectively take advantage of the redundant configuration of the control surface, prevent the system from losing control caused by the fault of the control surface, and enhance the safety and reliability of the system.
Longitudinal Control Technology for Automatic Carrier Landing Based on Model-compensated Active Disturbance Rejection Control
Authors: Yang Wenqi , Zhou Siyu , Lu Jianhua , Song Liting
Published: April 2023

Carrier aircraft landing is a system engineering with strong nonlinear, strong coupling, and complex environmental interference. Landing control is one of the key technologies for carrier aircraft landing, which directly affects the success of the landing. A longitudinal decoupling control method based on Model Compensated Linear Active Disturbance Rejection Control (MCC-LADRC) is proposed for tracking the deck motion and maintaining the attack angle in the final stage of the carrier landing. The simulation results show that compared with the PID control and traditional LADRC strategy, the MCC-LADRC method can not only control the carrier aircraft to track the deck motion synchronously and accurately, improve the landing accuracy and anti-disturbance capability but also has a good attack angle retention effect and eliminate the coupling between the pitch angle and the attack angle.
Analysis of harmonic resonance amplification caused by AC submarine cable integration of offshore wind farm
Authors: Gu Wen , Zheng Chaohang , Yang Hongyu , Wu Xi , Wang Hong , Xu Haohui
Published: April 2023

Offshore wind power plants (WPPs) using AC submarine cables connected to the power grid may experience harmonic resonance and harmonic amplification that are not common in onshore wind farms under the action of the distributed capacitance of submarine cables, which seriously threatens the safe and reliable operation of offshore WPPs. To investigate the influencing factors of harmonic amplification in offshore WPPs, a scalable state space-based modeling method for large-scale offshore WPPs were established. Moreover, the root locus method was used to study how the factors including that grid short-circuit capacities, cable parameters and the number of wind turbine generators (WTGs) affect the resonance modes. Finally, an offshore WPP in Jiangsu was built on the MATLAB/Simulink simulation platform, and the analysis results verify the correctness of the theoretical analysis.
Vehicle-Mounted Platform for Autonomous Take-off and Landing of Unmanned Aerial Vehicles
Authors: Yang Zhen , Li ChangLong , Jiang Nan , Shen YiCheng , Huang Wei
Published: April 2023

By expounding and proving the technical background of and demand for the platform for the take-off and landing of unmanned aerial vehicles (UAVs), and by analyzing the necessity in combination with current domestic and overseas situations, this paper reveals how a vehicle-mounted platform for take-off and landing of UAVs consisting of multiple connecting rods was developed. Meanwhile, the feasibility of the technology of the vehicle-mounted platform for take-off and landing consisting of multiple connecting rods was verified from multiple aspects by utilizing precision transmission technology, a general mechanical model, and a proof-of-principle prototype.
Study on Double-Resonant Characteristics of Load Simulation System for Electro-Hydraulic Servo Mechanism
Authors: Song Enming , Yin Chuanwei , Wang Yaqi , Chang Dongyan
Published: April 2023

The electro-hydraulic servo mechanism and engine realize thrust vector control together. Due to the low natural frequency of the engine, the dynamic characteristics of the test process show the result of double-resonance. The load simulation system can improve the efficiency of production tests and replace the actual engine in the production process. This paper fully considers the resonant problem of the engine, gives the relevant structural design scheme and parameter adjustment method to the load simulation system, and tests and analyzes the resonant characteristics. It aims at changing the resonant characteristics of the load simulation system by designing and adjusting the connection stiffness and torsional stiffness to achieve the real load condition.
Study on automatic lane change trajectory control of intelligent vehicle on expressway
Authors: Deng Huan , Wang Jian , Yang Jun , Du Ruofei , Hai Zhenyang , wang Yunjing
Published: April 2023

Aiming at the dangerous working condition of the front car driving at low speed, a safety distance model using the vehicle braking process is proposed to determine the best time for intelligent vehicles to change lanes. Based on the fitting method of quintic polynomial, an automatic lane change fitting trajectory is constructed, and the LQR algorithm is used to achieve accurate tracking. Through the joint simulation and experiment of CarSim, PreScan, and MATLAB/Simulink, it is shown that the established lane change trajectory control model can determine the best time for intelligent vehicles to change lanes, plan safe and comfortable lane change trajectory, and achieve good tracking effect.
Slow time-varying MIMO-OFDM modulation and coding for underwater acoustic channels
Authors: Cong Ying , Wu Jian , Jiao KeKe , Shi Heng , Sun YiMin
Published: April 2023

The underwater acoustic channel has the characteristics of limited available bandwidth and serious multipath fading. This paper uses orthogonal frequency division multiplexing (OFDM) and multiple input multiple output (MIMO) to solve this problem. As one of the core technologies of the MIMO system, space-time coding is implemented simultaneously in time and space to overcome spatial interference. On this basis, this paper proposes a precoding technique further to reduce the bit error rate of underwater acoustic communication.
Fractional Low-Order Blind Equalization Algorithm Based On SAPSO Optimization under Impulsive Noise
Authors: Tang Jun , Deng Zhaocai , Dang Zhaokai , Li Chuanqing
Published: April 2023

To address the problem that the traditional constant mode blind equilibrium algorithm (CMA) cannot converge stably in a water channel under α-stable distributed noise, we propose a fractional low-order blind equilibrium algorithm (SAPSO-FLOSCMA) based on simulated annealing particle swarm algorithm optimization. The algorithm introduces a simulated annealing operation in the particle swarm algorithm (PSO) to make the population accept the difference solution with a certain probability of accepting the difference solution to enhance the ability of the PSO algorithm to jump out of the local optimal solution. Then the cost function of the FLOSCMA algorithm is used as the fitness function of the SAPSO algorithm, and the global optimal solution is iteratively searched by using the SAPSO algorithm. The global optimal solution is used as the initial weight vector of the equalizer. The underwater acoustic simulation results show that compared with the CMA and FLOSCMA, the algorithm improves the convergence speed and reduces the inter-code interference.
Helimak control system
Authors: Yang S.Q. , Wen F. , Wu M.Q. , Li H. , Zhu X. , Hao B.L. , Li G.S. , Lin X.D. , Gao X.
Published: April 2023

The excellent wall condition is essential for fusion devices
to generate reproducible high-parameter plasma. Wall conditioning
techniques should be validated before applying on large fusion
devices to reduce potential risk. Helimak, a toroidal steady state
magnetic confinement device, was reassembled and upgraded to a
technical validation platform for wall conditioning. A new control
system has been developed to achieve the upgrade of Helimak. The
control system is based on a distributed control architecture, which
provides not only efficient development but also flexible control
mechanisms. For each auxiliary subsystem, a corresponding local
control module is developed to drive and control a variety of
equipment. The control network ensures real-time transmitting of the
parameters and data. A dedicated trigger network and timing control
module can improve synchronization and real-time performance. Data
acquisition system based on mature commercial busses provides
sufficient data acquisition capabilities for diagnostic tools. The
data management system uses MDSplus to provide convenient data
access. An independent interlock and safety system is designed for
comprehensive and reliable personal protection. After engineering
commissioning, the Helimak has realized wall conditioning by
electron cyclotron resonance heating (ECRH) plasma at different
resonance positions. The flexibility of control systems allows the
installation of more wall conditioning tools in the future that will
provide the ability to validate combined wall conditioning
techniques. Helimak will become a low-cost, reliable technology
verification platform, which will help to achieve advanced scenarios
in tokamak and stellarator.
Arabic and the Postfrancophone Poetics of Maghrebi Literature
Authors: elhariry yasser
Published: April 2023

As a discipline, francophone postcolonial studies defaults to several familiar tropes. In the Maghrebi context, one of them involves substituting historical events for literary ones. History has long offered the primary organizational rubric for many forays into the field, whose long and ongoing colonial struggles remain unresolved on either side of the Mediterranean littoral. A common battleground of the region’s postcolonial aesthetic and sociological configurations revolves around the choice of language: Should the postcolonized continue to write in the colonizer’s language? A postfrancophone poetics disrupts much of this terrain. It gestures toward one way out of the postcolonial lingual deadlock by eschewing the historical event as structuring principle and offering literary rather than historical markers—a constellation of references that isolates the fundamental plasticity of the french language and mollifies it with translation and intertextuality. Beneath the surface tension of francophone Maghrebi literature’s invariably french-language appearance, the modernism of french poetics and the deep historical intertext of Islamic scripture and classical Arabic lyric freely, incessantly weave in and out of one another. A postfrancophone poetics ciphers historicity, ever on display for the curious reader.
Magnetoreception and Bird Navigation
Authors: Wiltschko Roswitha , Wiltschko Wolfgang
Published: April 2023

The magnetic field of the earth provides birds with navigational information, with birds having two different receptor systems, one for the direction, the other for the intensity of the geomagnetic field. The direction of the geomagnetic field is used as a compass, with the avian magnetic compass being an inclination compass not recording the polarity of the field. The respective directional information is perceived by light-dependent radical pair processes in the eyes, with cryptochrome, a photopigment with the chromophore flavin adenine dinucleotide as receptor molecule. It is transmitted by the optic nerve to the brain, where it is processed by parts of the visual system. The magnetic compass not only serves to orient avian flights but also acts as a reference system for route reversal, calibrating the astronomical compass systems, and in migratory birds, as reference for the innate information on the migratory direction. Magnetic intensity and inclination that show gradients from the poles to the magnetic equator are part of the mechanisms that allow birds to determine their position. Intensity is perceived by receptors based on magnetite, a permanently magnetic material. The effect of a brief, strong magnetic pulse and its duration indicates that superparamagnetic particles are involved. The respective information is transmitted by the ophthalmic branch of the trigeminal nerve to the trigeminal brainstem complex in the brain. Testing birds in magnetic fields of a distant site, i.e., magnetically simulating a displacement, documents that magnetic intensity and inclination are very most important components of the navigational “map” that enables birds to determine their position relative to the goal and thus derive the compass course leading to this goal. Furthermore, certain magnetic conditions act as signposts and elicit specific spontaneous responses.
Theater, Drama, Education, and Pasifika Youth in Aotearoa New Zealand
Authors: Johansson Michelle
Published: April 2023

Pasifika people constitute a young, diverse, and growing portion of the population of Aotearoa New Zealand, with multiple cultural identities originating in the Cook Islands, Niue, Tokelau, Samoa, Tonga, Fiji, Tuvalu, Tahiti, and Kiribati. Pasifika people are also subject to both new and historical disparities in income, employment, education, housing, and health in comparison with other ethnic groups. Significantly, education in Aotearoa continues to fail Pasifika youth, reporting a persistent long brown tail of underachievement in standards-based assessment. Multiple government interventions have been implemented to address these increasing disparities, but these have been ineffective in achieving the widespread systemic change necessary for true equity.

Pasifika youth are regularly required to code-switch between Western colonial worldviews, systems, and structures and those of indigenous-Oceania. Theater in Aotearoa provides a powerful site in which to navigate these multiple cultural identities, advocate for societal change, and negotiate the heritage literacies associated with storytelling and the performing arts. South Auckland, in particular, is a crucible for nurturing young Pasifika creative artists interested in re-storying their world.
The Global Response of Universities and Colleges to the COVID-19 Pandemic and Their Post-Pandemic Futures
Authors: Croucher Gwilym
Published: April 2023

For universities and colleges around the world the COVID-19 pandemic caused significant disruption. The pandemic created challenges and possibilities, as well as amplifying existing trends for higher education institutions. The initial pandemic-related disruption affected universities and their students in many countries and had widespread effects on their operations and teaching. In particular, the temporary closure of campuses had implications for the “on campus” experience, and the closure of inter- and intra-national borders reshaped patterns of the international movement of students. The widespread and rapid shift to online education showed possibilities and limitations for technology-enhanced learning. In addition, the pandemic had an impact on government priorities for funding higher education when many were faced with unprecedented fiscal pressures, leading to funding reductions for some universities.
The Dutch East India Company in South Asia
Authors: van Meersbergen Guido
Published: April 2023

The Dutch East India Company (VOC, 1602–1799) developed into Europe’s largest commercial and colonial power in 17th-century Asia. Within its extensive intra-Asian trading network centered on Batavia (Jakarta), the Indian subcontinent and Ceylon (Sri Lanka) occupied a pivotal position. The VOC’s desire to tap into the exchange of Indian cloth for fine spices from the Maluku Islands first drove the Dutch to the Coromandel Coast, while Surat’s position as the preeminent maritime hub of the western Indian Ocean and Bengal’s status as a major exporter of silk and cottons attracted the Company to the Mughal Empire. Between 1638 and 1663, the VOC also displaced the Portuguese from their colonial holdings in Ceylon and the Malabar Coast, the world’s only source of high-quality cinnamon and an important producer of pepper, respectively. In Mughal India, the Dutch presence was limited to trading posts from which it conducted trade on conditions set by the imperial authorities, whereas along the Coromandel and Malabar Coasts the VOC possessed fortresses, and in Ceylon it acted as a territorial power exercising colonial rule over several hundred thousand Sinhalese and Tamil inhabitants. In all parts of South Asia, the Company’s position relied on and was maintained through diplomatic relations with local rulers. The various commercial, diplomatic, and colonial interactions gave rise to important forms of cultural exchange and knowledge production in the realms of art, religion, language, and botanical science, which testify to significant cross-cultural connections and mutual influences. The VOC maintained a dynamic trade in South Asia until the final quarter of the 18th century, when its Indian possessions were captured by the British first during the Fourth Anglo-Dutch War (1780–1784) and again in 1795 to 1796 during the French Revolutionary Wars.
Afghan Circulations in the Persianate World, c. 1000–1800
Authors: Archambault Hannah
Published: April 2023

This article traces the movement of Afghan peoples across the Persianate world between 1000 and 1800 ce. Afghans rose to prominence with the rise of the Delhi Sultanate, the first Muslim-ruled polity in northern India. Over the following centuries Afghans moved throughout the Persianate world, a region stretching from the Ottoman territories in the west to the courts of Southeast Asia and as far north as the trading center of Astrakhan. In the territories of what is now the modern nation-state of Afghanistan, a series of Muslim dynasties, including the Ghaznavid (c. 977–1186) and Ghorid Sultanates (c. 1011–1215) as well as a Timurid court based in Herat (c. 1405–1507) and regional representatives of the Safavid and Mughal Empires, were all led by Turkic, Tajik, and other Turco-Mongol lineages. It was not until the 18th century with the Durrani Empire (c. 1747–1842) that an explicitly Afghan-led government came to power in Afghanistan itself. Instead, the main focus of Afghan society and activity was centered within the Indian subcontinent and its mountainous northwestern frontier. As with many other premodern communities, Afghans built their careers around mobility. From humble origins as pastoral-nomadic peoples based in the Sulayman Mountains and their environs, they built careers as peripatetic merchants and as soldiers, ruled as kings, and traveled India’s highways and byways as mendicants. Afghans also became specialists in frontier zones, cultivating relationships across cultural and political frontiers that helped to facilitate integration across regions. Their political interests were informed by their economic interests, and many moved fluently between roles as merchants and as courtly and military officials. Afghans served and eventually ruled the Delhi Sultanate, became nobility within the Mughal Empire and organized its opposition, and established regional centers of Afghan power across the subcontinent. At the end of the 18th century, it was the rising influence of the British East India Company authority and their efforts at controlling the circulation of peoples, ideas, and materials that eventually marginalized Afghans in Indian society, reconstructing them as outsiders.
Ogot, Grace
Authors: Kurtz J. Roger
Published: April 2023

Grace Emily Akinyi Ogot (1930–2015), a leading Kenyan writer and politician, was a pioneering figure whose professional accomplishments spanned the independence and postindependence eras in East Africa. Until her death at age eighty-four, Ogot was an acclaimed cultural leader within her Luo community, as well as in her nation of Kenya. While she also worked in the fields of nursing and journalism, Ogot is best remembered for her political success, her groundbreaking achievements as an author of short stories and novels, and being chronicler of Luo folk tales. In all areas of her work, Ogot developed a reputation as a prominent advocate for women’s concerns.

As an author, Ogot belongs to the first generation of Kenyan writers. This group may be defined as those writers who were born and educated during the colonial period, but whose writing continued into the postcolonial era. She was the first Luo writer and the first Kenyan woman to win international acclaim for her creative writing. Other well-known Luo women writers from Kenya include Asenath Bole Odaga, Margaret Ogola, Marjorie Oludhe Macgoye, and Yvonne Adhiambo Owuor. Ogot wrote both in English and in Dholuo, the language of the Luo people. She is best known for her works of realist fiction, her promotion of traditional myth and folklore, and her books for children. She began publishing short stories in East African journals in the 1960s. Her best-known works are her novel The Promised Land (1966) and her short story collection Land without Thunder (1968). These were the first creative works written by a woman to be published by the East African Publishing House, the region’s first locally owned and managed publishing firm.

In national politics, Ogot represented her region as a member of parliament, and she served as an assistant minister in the national government. She served as a delegate to the United Nations General Assembly in 1975 and to UNESCO in 1976. She was married to Bethwell Ogot, a leading Kenyan historian. Together, they represented one of Kenya’s most influential and publicly recognized couples due to their prominent national positions. Through her writing and political activities, especially as she used those activities to promote positive social change for women, Ogot will be remembered as someone whose life both reflected and influenced the social dynamics of 20th-century Kenya.
Homelessness and Vaccination Strategies: Problems and Potential Solutions to Vaccinate Vulnerable Populations
Authors: Mitevska Elena , Gill Priyanka , Ghosh Monty
Published: April 2023

People experiencing homelessness (PEH) are at a higher risk of vaccine-preventable illnesses. They have higher rates of chronic illnesses that predispose them to communicable diseases, and this is compounded by poor access to sanitation. While vaccination is especially important in PEH, they tend to have lower rates of vaccine uptake compared to the general population. Factors impacting this discrepancy include difficulty accessing vaccines and public health programs, lack of access to primary care services, and distrust of the health care system. Despite this, there is evidence to suggest that many PEH are accepting of vaccinations and are willing to get vaccinated provided the right approach and interactions. Understanding client-specific barriers along with education and counseling are key to improving vaccine uptake in PEH, and programs targeted specifically at PEH can improve vaccine uptake and ultimately the health of PEH.
Big Data and Urban Health
Authors: Stevenson Mark , Thompson Jason , Ho Thanh
Published: April 2023

Understanding the varied effects of urban environments on our health have arisen through centuries of observation and analysis. Various units of observation, when compiled spatially or linearly, have provided considerable understanding of the causal pathways between environmental exposures in cities and associated mortality and morbidity. With growing urban agglomerations and a digital age providing timely and standardized data, unique insights are being provided that further enhance the understanding of urban health. No longer is there a potential lack of urban data; over the 2010–2020 decade alone, the resolution and standardization of satellite and street imagery, for example, alongside methods of artificial intelligence such as self-supervision methods, have meant that technology and its capacity have surpassed the accuracy and resolution of many administrative data collections typically used for urban health research. From Bills of Mortality in 1665 to 20th century surveillance systems to the innovation and global reach in the period of “big data,” data has been the mainstay of decision support systems over the centuries. This new world of big data characterized by volume, velocity, variety, veracity, variability, volatility, and value is paramount to answering the significant urban health challenges of the 21st century.
The Archaeology of Soapstone Figurines in West Africa
Authors: Adekola Kola
Published: April 2023

Stone working technology is very rare in West Africa. Unlike other artistic techniques, stone working even in ancient times was limited to certain locations. This could be a result of the fact that not all stones can be worked even by those who have the skills to do so. The raw material for stone working—steatite—must be present in a locality or nearby where it can easily be harvested. A second requirement is the presence of highly skilled individuals who have knowledge of stone carving. Also fundamental, perhaps, is a social environment that enables stone working technology to thrive: for a society or group to engage in carving stones, the group must be administratively stable—that is, the organs of government (whether sophisticated or elementary) must have the capacity to cater to the artisans, or groups of artisans. Such a society must have a stable food supply.

Outside Nigeria, among the Mende people of Sierra Leone, stone carvings called “Nomoli” are found in caves and earthen mounds and are mostly discovered by farmers. The Mende believe in the spiritual potency of the carved objects. Hence, they place them in shrines and by their rice fields to increase the fertility of the crops. If the crops do not fare well, the little figures are whipped so that they will do better the following year.

The Esie figrines which were over a thousand pieces have been subject of study by scholars who have used the lenses of their different disciplines to have insights into what the soapstone represents as well as the identity of their makers. The makers of the soapstone figurines were agrarian people who organized themselves as a mini state. This enabled them to mobilize the necessary labor force that was required for the manufacture of the Esie soapstone figures.