Current Rise Research Articles

Synergistic Enhancement of Electron Dynamics and Optical Properties in Zeolitic Imidazolate Framework-8-Derived Zinc Oxide via Surface Plasmon Resonance Effects of Silver Nanoparticles under UV Irradiation.

This study investigates the surface plasmon resonance (SPR)-induced UV photoresponse of zinc oxide (ZnO) derived from zeolitic imidazolate framework-8 (ZIF-8) to assess the influence of silver nanoparticles (Ag NPs) on the photoresponse behavior of metal-organic framework (MOF)-derived ZnO. The initial synthesis involved a thermal treatment in air to convert ZIF-8 into ZnO. We noted enhanced optical absorption both in the UV and visible spectra with the deposition of Ag NPs onto the ZIF-8-derived ZnO. Additionally, the presence of Ag NPs in the ZnO resulted in a substantial increase in current, even without any light exposure. This increase is attributed to the transfer of electrons from the Ag NPs to the ZnO. Photocurrent measurements under UV illumination revealed that the photocurrent with Ag NPs was significantly higher-by two orders of magnitude-compared with that without Ag NPs. This demonstrates that SPR-induced absorption markedly boosted the photocurrent, although the current rise and decay time constants remained comparable to those observed with ZnO alone. Although Ag NPs contribute electrons to ZnO, creating a "pre-doping" effect that heightens baseline conductivity (even in the absence of light), this does not necessarily alter the recombination dynamics of the photogenerated carriers, as indicated by the similar rise and decay time constants. The electron transfer from Ag to ZnO increases the density of charge carriers but does not significantly influence their recombination.

Vulmob, a new multidimensional indicator of mobility vulnerability

Mobility enables to find jobs, go to school or meet people. However, long distances, high costs, car dependency and poor accessibility are sources of mobility vulnerabilities. The current rise in fuel prices may have a strong impact on mobility, especially for households that rely heavily on their cars. Moreover, the need to reduce air pollution and greenhouse gases emissions requires the implementation of ambitious environmental policies. It is therefore necessary to identify transport poor households, affected by financial issues, as well as vulnerable households whose mobility would be strongly impacted by changes in individual mobility conditions and would have difficulties to adapt to this situation. To this end, we construct VulMob, a multidimensional indicator made up of thirteen individual factors organized in four dimensions: financial resources and transport affordability, work constraints, heavy car use and accessibility and structural constraints. We apply this indicator to the Grenoble area, in France. Our results show that 9.6% are highly vulnerable, meaning that they face at least six vulnerability issues and 5.5% of the households face transport affordability issues. A typology of five profiles of highly vulnerable households shows that some are financially constrained; others are heavy car users, work at night or face public transport accessibility problems.

The Antinomies of Latvian Literary Realism

This article traces the social and literary contexts of Latvian literary realism. During its rise in the nineteenth century, Latvian realism was seen as developing along the general lines of European culture that helped to foster aesthetic diversity and innovative potential. These processes are the focus of the first part of the article. The subsequent reshaping and distortion of the concept of realism during the period of Soviet occupation are then scrutinized in some detail. The investigation follows in the footsteps of the current rise of interest in realism, considering its importance in a broad spectrum of contexts, and claims that realism is an innovative aesthetic practice of great historical and contemporary relevance. However, it has also frequently been misunderstood or consciously misinterpreted by representatives of other aesthetic trends as well as misused by political regimes. The article points toward the necessity of restoring a sound interpretation of realist aspirations and their social and aesthetic contributions.

Racial hydrologies

AbstractIn the South Carolina Lowcountry, near‐annual hurricanes and record‐breaking sea levels have led to disastrous flooding, overwhelming the region's historical tidal infrastructures and entrenched racial geographies. In response, Lowcountry governments, institutions, and residents have undertaken efforts at “perimeter protection,” raising dikes and seawalls to safeguard selected urban and rural plantation spaces from tidal flooding. Although perimeter protection is presented as a neutral resilience strategy, its practices and material forms reveal a close relationship between coastal protection and efforts to preserve landscapes of white supremacy. Such logics of perimeter protection contrast with everyday affective encounters with eroding coastlines and with the futures outside of bounded edges imagined by Black Charlestonians. By situating the region's hydrological history within the legacy of slavery and plantation extraction, and by following the effects of current sea level rise, we can see how historical hydrologies—which in this case are also racial hydrologies—are entangled with landscapes of contemporary environmental injustice.

Climate politics in global Hobbesian Jungle.

Climate change, largely triggered by human-induced greenhouse gases (GHGs) emissions, seems unstoppable. There was a strong rebound of anthropogenic emissions of CO 2, the preponderant GHG in terms of contribution to global warming, around the world after the COVID-19 lockdown. Also, there is still no widely accepted international treaty on curbing the anthropogenic emissions of CH 4 and N 2O, the second and third predominant GHG, respectively, so far. Thereby, prima facie, in respect to mitigating climate change, currently, humans have no aces up their sleeves. It seems that current temperature rise is not high enough to take alarm until the occurrence of tipping point. Climate-related international treaties, such as 2016 Paris agreement, are compromises among conflicting geopolitical pressures. However, currently, the climate treaties show little mandatory binding force on the signatories who are able to violate and then get off scot-free, thus may end up like a nostrum. Throughout the European history, I find that the only way, if at all, to achieve the peace or obedience of a treaty is via balancing powers, embodied in Bismarck's Realpolitik of Germany and Richelieu's Raison d'état of France. Similarly, the Chinese history in East Asia proved the significance of unadulterated ideological neutrality and Darwinian adaptability in the kaleidoscope of evolving circumstances in maintaining order and enforcement of international treaties through balancing the power of rivalries to constrain ever-recurring challengers for equilibrium. A successful policy needs to make a thorough analysis of all relevant factors to form a long-term strategic notion. Then, statesmen need to distill an array of nebulous, always contradictory options into a tenacious, controllable direction. Thereby, I suggest that, for better curbing global warming, climate agreements or climate club be incorporated into an overall geopolitical framework among the international communities.

A Review of Chinese as a Second Language Journal Publication Trends: The Case of Universiti Teknologi MARA

This study reviews the publication trends on Chinese as a second language, which indicates the current situation, research gaps, and potential directions for future research. This review examines Chinese as a second language journal publications produced by lecturers and researchers at Universiti Teknologi MARA (UiTM) since the publications are scattered without systematic organisation, making it difficult to determine which direction the research is headed and to foresee the topics of interest that will encourage future growth. This review conducted a systematic review of 75 journal articles published from 2013 to 2023, focusing on publication status and trends, co-authorship, and content scope. As a result, this study discovered a publication gap between general-UiTM-recognised journals and international-recognised journals. It proposed to broaden the expertise collaboration to international networking. This study also identifies population gaps, which urged conducting research at a wider range. In terms of content scope, research gaps were found in theoretical, conceptual, model, and tool-building research, as well as in-depth investigation of Chinese language, culture, and social studies. The incorporation of technology in future research is prospective due to the current rise in digital awareness. Moreover, learners’ behaviour in learning Chinese as a second language should be further investigated due to dispersive research. This systematic review contributes to the continuous development of researching and instructing Chinese as a second language in UiTM. It serves as a guide for other Malaysian higher education institutions with a similar research interest.

ATP-EMTP simulation of lightning protection system for multi-storey building

Multi-storey buildings with occupied highly technological instruments have more attraction possibilities of a lightning stroke than ordinary residential buildings. A protection system against lightning is necessary for these buildings and the level of the protection system performance is an issue to be examined. In this study, a protection system for a three-storey building is simulated in Alternative Transient Program-Electromagnetic Transients Program (ATP-EMTP). Distributed-parameter line models are used for the conductors of the protective system by modelling vertical conductors as nonuniform lines. The currents flowing in the critical conductors and the voltages at some critical points resulting by a lightning stroke are computed. The conventional lighting parameters required for structural protection such as lightning peak current, current rise time and time interval for the current flowing are determined. The effect of the radius of conductors in the protection system on the surge response is investigated.

Optimised projection welding of steel Bars

The article presents tests aimed at optimising the welding of bars, made of steel AISI1005 (ø 4.2 mm), in a cruciform configuration (i.e. using the cross-wire welding process). The authors identified research gaps and carried out a detailed numerical analysis of these cases. The research-related calculations involved the use of SORPAS software. The new areas of research included (i) bars with protective zinc coatings having various thicknesses of 0 µm, 5 µm, 10 µm and 30 µm, (ii) various welding current rise times (up-slope) and (iii) single and multi-pulse welding cycles. The tests were carried out using a DC 1 kHz inverter welding machine; the results concerning welding up-slope times were compared with those obtainable using a conventional AC 50 Hz welding machine. The results of the study, in the form of a welding technology with various values of up-slope time, have been implemented in industry. The inventive idea is protected by patent no. P.229445 at the Polish Patent Office.

Field tests of square and double exponential pulses for transient resistivity measurements using Wenner arrays and hemispheres

Models of frequency-dependent soil resistivity ρ(f) suggest the dual concept of time-dependent resistivity ρ(t) that, for high resistivity soil, increases from 100 ns to 100 μs, a range of time relevant for lightning backflashover performance calculations. Measurements of ρ(t) can be made by impressing impulse or step current and monitoring voltage rise. Time-dependent resistivity can be established with Wenner or Schlumberger probe arrays and also with oblique fall-of-potential measurements from buried hemispheres. Tests show that rectangular and double-exponential pulse currents both have value. Specialized evaluation using “Drained Net Charge” concepts may yield estimates of low-frequency resistivity ρo.

Marxism and the Critique of Antisemitism

Abstract Antisemitism is an increasingly prevalent aspect of public life in the West, both as a consequence of the growth of the far right across the board and through its mobilisation against Palestinian liberation and Palestine solidarity activism. While synagogues are targeted and far-right politicians revive ideas of Jewish global power, it is the left, Muslims, and Palestinians that are continuously constructed as the source of the current rise in hatred and violence against Jews. If historically the Marxist tradition engaged actively with the so-called Jewish question, in recent decades the subject has receded from focus. This shift took place as other forms of racism – directed at Muslims, Black populations, or migrants – became the basis for reactionary politics in the West. This article argues that while some of the assumptions that underwrote classical Marxist texts on the issue have been found wanting – perhaps most notably the inevitable (or desirable) character of the trend towards assimilation – they remain important starting points for making sense of our present, both by their method and their political commitment to liberation.

A Cost-Effective Current-Limiting Hybrid DC Circuit Breaker Based on Hybrid Semiconductors

DC circuit breakers (DCCBs) are the key equipment to rapidly interrupt the fault current in high-voltage DC power grids and ensure the safe operation of the system. However, most DCCBs do not take current-limiting measures and rely solely on current-limiting reactors in the system to limit the rate of current rise during the interruption process. The extensive use of fully controlled power electronic devices in circuit breakers (CBs) results in high costs. To address the issues above, this paper proposes a DCCB topology with a current-limiting function based on thyristors and diodes, which can reduce the cost of CB while ensuring reliable interruption. The impact of various parameters on CB performance is analyzed using numerical calculations to optimize the parameters. Then, a simulation model of a 500 kV/16 kA DCCB is built in PSCAD/EMTDC, and the performance of the proposed CB topology is compared with the other CB topologies. By comparison, the proposed DCCB topology can reliably isolate fault currents and reduce the amplitude of fault currents and the cost of CBs. Significantly, the energy absorbed by the metal oxide varistor (MOV) during the interruption process decreases by 64.2%, reducing the cost and volume of the MOV. Finally, the feasibility of the CB is further verified in the ±500 kV 4-terminal high-voltage DC power grid simulation model. The results show that the proposed DCCB topology can limit the fault current rise rate, interrupt and isolate the fault reliably, and reduce the cost.

Transient turn-on characteristics of Si RBDT and SiC MOSFET under nanosecond current pulse range

With the development of pulse power supplies, solid-state semiconductor switches are required to have fast switching speeds and low losses. Both Reverse blocking diode thyristor (RBDT) and silicon carbide metal oxide semiconductor field effect transistor (SiC MOSFET) have fast turn-on speed, making them suitable candidates for short pulse generator. In this paper, the transient turn-on characteristics of Si RBDT and SiC MOSFET are analyzed theoretically and validated experimentally. Si RBDT and commercial 1.2 kV/81A SiC MOSFET are comparatively investigated in switching current pulse with a rise time of several hundreds of nanoseconds. (1) The anode current of RBDT could rise exponentially because of the latch-up effect of Si RBDT, while the drain current of SiC MOSFET tends to be saturated. (2) Utilizing the current rise time (Trise) to represent the switching speed, SiC MOSFET can switch faster when the current is lower than 400A. With the increase of the current, Si RBDT presents faster turn-on speed and lower switching loss due to the regenerative action of the two coupled transistors. (3) The transient characteristics of Si RBDT include a voltage-controlled inductance, while SiC MOSFET contains a current-controlled inductance based on the current rise time, respectively. With the increasing of the main voltage, the equivalent inductance of Si RBDT decreases and tends to be saturated when the main voltage is higher than half of the breakdown voltage of Si RBDT. For SiC MOSFET, the equivalent inductance increases until the drain current remains stable for a given gate voltage. This paper confirms the advantages of Si RBDT and SiC MOSFET in different situations.

Determining sea-level rise in the Caribbean: A shift from temperature to mass control

Tropical Small Island Developing States (SIDS), such as those in the Caribbean, are among the most vulnerable to the impacts of climate change, most notably sea-level rise. The current sea-level rise in the Caribbean is 3.40 ± 0.3 mm/year (1993–2019), which is similar to the 3.25 ± 0.4 mm/year global mean sea-level (GMSL) rise (1993–2018). Throughout the year, Caribbean seasonal sea-level variability is found to respond to sea surface temperature variability. Over the past few decades, the trend in Caribbean Sea-level rise is also found to be variable. Satellite altimetry and steric sea-level records of the Caribbean region reveal a shift in the late 2003-early 2004, which separates two distinct periods of sea-level rise. Thermal expansion dominates the sea-level trend from 1993–2003. Following this period, there is an increased trend in sea-level rise, with a dominance of mass changes from 2004–2019, as confirmed by GRACE data. During this period, the sea-level trend is 6.15 ± 0.5 mm/year, which is 67% faster than the most recent estimates of global mean sea-level rise provided by the Intergovernmental Panel on Climate Change (3.69 ± 0.5 mm/year for the period 2006–2018). Despite its reduced importance, increasing temperatures contribute greatly to sea-level rise in the Caribbean region through thermal expansion of ocean water, hence there is a need to limit the current trend of global warming.

6σ Robust Lightweight Design of the GIL/GIS Bus Based on Co‐Simulation of Insulation, Current Flow, and Mechanical Stress

GIL/GIS bus is widely used in the field of power transmission and distribution, and the demand for lightweight is becoming more and more prominent. To reduce the weight of the bus and ensure the safety and reliability of the structure, a new 6σ robust design method of the GIL/GIS bus based on electric‐thermal‐mechanical co‐simulation is proposed. Taking a 550 kV/5000A bus as the initial structure, considering the uncertainty of product size and performance, a 6σ robust lightweight model of bus insulation electric field strength, current temperature rise, and mechanical stress multi‐performance co‐simulation is established. The finite element numerical calculation method is used to calculate and analyze the performance parameters of the bus. The Kriging surrogate model is used to form the response surface, and the optimal bus structure is obtained by genetic algorithm. The results show that after the robustness optimization, the performance of the bus meets the design requirements, the weight per meter decreased from 65.11 to 39.12 kg, and the lightweight effect is remarkable. Compared with the traditional deterministic optimization design, the reliability of the structure is improved. The new method of the GIL/GIS bus lightweight design proposed in this study has high feasibility and application prospects, which can provide new ideas for the development of gas‐insulated electrical equipment. © 2024 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC.

Physical insight into turn‐on transient of silicon carbide gate turn‐off thyristor

AbstractSilicon Carbide (SiC) Gate Turn‐off (GTO) thyristor is regarded as a promising option for pulsed power applications; however, the formation of high di/dt has been constrained by the slow current rise transient phase and the turn‐on current heterogeneity over the chip device. In this paper, a practical integrated multi‐cell simulation is performed to physically characterize the turn‐on transient of SiC GTO thyristor. Through examining electrical coupling between adjacent cells caused by both parasitics of electrode metallization and carrier travelling via SiC, the current distributions are observed, and the carrier transport dynamics are analyzed in detail. Furthermore, physical mechanisms dominating the current heterogeneity among multi‐cells are discovered in depth. It is revealed that the current heterogeneity during the turn‐on transient is primarily resulted from the Gate signal delay caused by the Gate Runner metallization, and the lateral interaction from adjacent semiconductor regions adds to this inhomogeneity; however, this situation can be improved once the electrical distance between each Anode contact and the Anode electrode gets lowered. Design method for turn‐on performance improvement is also proposed accordingly. Besides, based on the analysis conducted on the multi‐cell simulation results, the possible reason of the extremely slow current rise transient phase is speculated and experimentally verified. The improvement in the comprehension of SiC GTO's turn‐on transient, which cannot be obtained from the traditional investigation from the viewpoint of one elementary cell, will provide guiding principles helping in directing future efforts to advance the improvement of device design technology.

Lowering the Schottky Barrier Height by Quasi-van der Waals Contacts for High-Performance p-Type MoTe2 Field-Effect Transistors.

Two-dimensional (2D) transition-metal dichalcogenides (TMDs) offer advantages over traditional silicon in future electronics but are hampered by the prominent high contact resistance of metal-TMD interfaces, especially for p-type TMDs. Here, we present high-performance p-type MoTe2 field-effect transistors via a nondestructive van der Waals (vdW) transfer process, establishing low contact resistance between the 2D MoTe2 semiconductor and the PtTe2 semimetal. The integration of PtTe2 as contacts in MoTe2 field-effect transistors leads to significantly improved electrical characteristics compared to conventional metal contacts, evidenced by a mobility increase to 80 cm2 V-1 s-1, an on-state current rise to 5.0 μA/μm, and a reduction in Schottky barrier height (SBH) to 48 meV. Such a low SBH in quasi-van der Waals contacts can be assigned to the low electrical resistivity of PtTe2 and the high efficiency of carrier injection at the 2D semimetal/2D semiconductor interfaces. Imaging via transmission electron microscopy reveals that the 2D semimetal/two-dimensional semiconductor interfaces are atomically flat and exceptionally clean. This interface engineering strategy could enable low-resistance contacts based on vdW architectures in a facile manner, providing opportunities for 2D materials for next-generation optoelectronics and electronics.

The Phenomenon of a Cathode Spot in an Electrical Arc: The Current Understanding of the Mechanism of Cathode Heating and Plasma Generation

A vacuum arc is an electrical discharge, in which the current is supported by localized cathode heating and plasma generation in minute regions at the cathode surface called cathode spots. Cathode spots produce a metallic plasma jet used in many applications (microelectronics, space thrusters, film deposition, etc.). Nevertheless, the cathode spot is a problematic and unique subject. For a long time, the mechanisms of spot initiation, time development, instability, high mobility, and behavior in magnetic fields have been described by approaches that caused some controversy. These spot characteristics were discussed in numerous publications over many years. The obscurity and confusion of different studies created the impression that the cathode spot is a mysterious phenomenon. In the present work, a number of typical representative publications are reviewed with the intention of clarifying problems and contradictions. Two main theories of cathodic arcs are presented along with an analysis of the experimental data. One of the approaches illustrates the cathode heating by Joule energy dissipation (volume heat source, a sharp rise in current density, etc.), nearly constant cathode potential drop, and other certain initial conditions. On the other hand, a study using a mathematically closed approach shows that the spot initiation and development are determined not by electron emission current rise but by a rise in arc power density, affecting heat sources including the energy of ion flux to the cathode (surface heat source).

Electroporation in Cancer Therapy: A Simplified Model Derived from the Hodgkin-Huxley Model.

Cancer remains a global health challenge, necessitating effective treatments with fewer side effects. Traditional methods such as chemotherapy and surgery often have complications. Pulsed electric fields and electroporation have emerged as promising approaches to mitigate these challenges. This study presents a comprehensive overview of electroporation as an innovative tool in cancer therapy, encompassing critical elements such as pulse generators and delivery devices. Furthermore, it introduces a simplified reversible electroporation model grounded in the Hodgkin-Huxley model. This model ensures resting potential stability by regulating ionic currents. When membrane charges reach the electroporation threshold, the model swiftly increases the fraction of open pores, resulting in a rapid rise in electroporation current. Conversely, as the transmembrane potential drops below the threshold, the model gradually reduces the fraction of open pores, leading to a gradual decline in electroporation current, indicating pore resealing. This model contributes to easier modeling and implementation of reversible electroporation dynamics, providing a valuable tool for further exploration of electroporation for cancer therapy.

Interdisciplinary care for gender diverse adolescents. The example of the Centre hospitalier universitaire vaudois (CHUV)

This article outlines the management of transgender and non-binary adolescents at CHUV. The current rise in visibility of this topic is associated with an increased demand for intervention and at the same time with an increased generation of continuously expanding medical evidence to guide interventions. The close collaboration among various specialized adolescent health services enables an interdisciplinary evaluation of diagnostic elements and indications for potential psychological, social or medical interventions. This article underscores the significance of an interdisciplinary and individualized approach to transgender and non-binary adolescents, respecting the diversity of the human being.

Lightning current Risetime influence on inductive coupling effect of secondary shield cable in substation

Secondary cables are susceptible to lightning surge currents when substation is struck by lightning. Little work has been made to the effects of surge currents in substation secondary cables, particularly the effects of surge current rise time. Six types of simulated lightning surge currents with different rise times, ranging from 5.7 μs to 25.4 μs, were injected into the substation grounding grid, and the inductive voltage from core wire to ground and the shield current in the closed loop of the buried secondary cable were measured simultaneously. The inductive coupling characteristics and the effect of rise time on shielding factor (SF) of buried secondary cables were investigated using time-frequency domain method. The results indicate that the surge current with shorter rise time will induce higher core-wire voltage and higher the shield current on the secondary cable. Double-end grounding of the shielding layer can significantly reduce the cable coupling response, especially reduce the high-frequency component of the inductive voltage at 10 to 100 kHz with steeper surge currents. The SF of secondary cable increases exponentially from 1.91 dB to 8.15 dB as the rise time of the lightning surge current decreases.