Current Generation Research Articles

Light-Field-Driven Non-Ohmic Current Generation by an Intense THz Pulse in a Weyl Semimetal

Light-Field-Driven Non-Ohmic Current Generation by an Intense THz Pulse in a Weyl Semimetal

Strengthening the Contribution of the Investigations of Basil Davidson’s A History of West Africa 1000-1800

This article aims to assess the contribution of Black Africa to the progress of humankind at the time of the Great Empires and even before. To do so, Africans must immerse themselves in the knowledge of their past. The background of West African civilization and history must serve as a rear-view mirror for the advancement of the current generation. Indeed, Basil Davidson, who was an important recorder of information about Africa, edifies us on the main discovery of this older generation based on his study of African iron tools. This invention contributed enormously to the improvement of the population’s well-being and the creation of families, and later villages. These were followed by the foundation of the first kingdoms, culminating in empires such as Ghana, Mali, Songhayand other kingdoms like Senegamby, Mossi, Igbo, Asante, Bono, and Kanem-Bornu. During this period of prosperity, man belonged to his community. The people of the past were imbued with values that placed the interests of the group above those of the individual. Then came the interval between the end of the empires and the independence of West African countries. During this era, the influence of Europeans through slavery and colonization was a heavy weight on their heads. The methodology uses both descriptive and qualitative analyses. Utilizing the framework of Afrocentricity theorized by Molefi Kete Asante we will examine Davidson’s orientation to the data he discussed in order to seek an African perspective on the facts. It is from this angle that this article enlightens on how the writer addresses this question of civilization and prosperity in his work.

Optimal orbit transfer of single-tether E-sail with inertially fixed spin axis

AbstractThis study analyzes the optimal transfer trajectory of a spacecraft propelled by a spin-stabilized electric solar wind sail (E-sail) with a single conducting tether and a spin axis with a fixed direction in an inertial (heliocentric) reference frame. The approach proposed in this study is useful for rapidly analyzing the optimal transfer trajectories of the current generation of small spacecraft designed to obtain in-situ evidence of the E-sail propulsion concept. In this context, starting with the recently proposed thrust model for a single-tether E-sail, this study discusses the optimal control law and performance in a typical two-dimensional interplanetary transfer by considering the (binary) state of the onboard electron emitter as the single control parameter. The resulting spacecraft heliocentric trajectory is a succession of Keplerian arcs alternated with propelled arcs, that is, the phases in which the electron emitter is switched on. In particular, numerical simulations demonstrated that a single-tether E-sail with an inertially fixed spin axis can perform a classical mission scenario as a circle-to-circle two-dimensional transfer by suitably varying a single control parameter.

Thrombogenicity of biodegradable metals

Biodegradable metals offer a promising means to ameliorate many of the long-term risks associated with vascular devices made of conventional biostable stent metals. While numerous biodegradable metal alloys have been developed and characterized in animal models, knowledge of their blood reactivity and thrombogenicity remains unknown. Metal hemocompatibility is particularly valuable because current generation drug-eluting stents pose a significant long-term thrombosis risk. In this study, four pure metals, widely used as degradable base materials (Fe, Zn, Mg, and Mo), and three alloys commonly used in cardiovascular devices [NiTi, CoCr, and stainless steel (SS)] were evaluated. This work examined how each of these metals activate platelets, coagulation factors, and inflammation using in vitro hemocompatibility assays and a clinically relevant ex vivo non-human primate arteriovenous shunt model. Testing found that while all metals promoted a downstream activation of platelets and coagulation in flowing whole blood, platelet and fibrin attachment to Mg was markedly reduced. Additionally, Fe and Mo trended toward higher platelet attachment and contact pathway activation. Overall, the results suggest that Mg may delay clot initiation, but not eliminate clot formation, indicating the importance of understanding thrombosis in Mg alloys that are currently being developed for clinical use as biodegradable stents.

Reducing Aerodynamic Drag on Roof-Mounted Lightbars for Emergency Vehicles

This paper investigates the impact of contemporary lightbars on vehicle fuel efficiency with a focus on quantifying their effects on fuel consumption and exploring strategies to improve drag performance through modifications. Simulations showed an 8–11% increase in drag for square-back vehicles, with greater penalties outlined for vehicles with rear-slanting roofs. Given the moderate drag increase, the impact on the driving range, especially for electric vehicles, remains minimal, supporting the continued use of external lightbars. Positioning experiments suggest marginal drag reductions when lowering the lightbar to its lowest position due to additional drag effects that can be caused by the mounting mechanism in its condensed form. Angling the lightbar showed negligible drag increases up to an angle of 2.5 degrees, but beyond that, a 4% increase in drag was observed for every additional 2.5 degrees. Additionally, fitting drag-reducing ramps ahead of the lightbar yielded no significant drag savings. Noise analysis identified that the lightbar’s wake and rear surfaces were responsible for the largest production of noise. The optimal lightbar design was found to incorporate overflow rather than underflow and rear tapering in sync with roof curvature. Appendable clip-on devices for the lightbar, particularly rear clip-ons, demonstrated appreciable drag reductions of up to 2.5%. A final optimised lightbar design produced a minimal 2.8% drag increase when fitted onto an unmarked vehicle, representing a threefold improvement compared with the current generation of lightbars. This study advances the field of lightbar aerodynamics by precisely quantifying drag effects by using highly detailed geometry and examines the significance of optimal positioning, angle adjustment, and appendable clip-on devices in greater depth than any existing published work.

The role of financial inclusion, technology innovation, energy and environmental degradation in determining sustainable growth in Asia

AbstractSustainable growth is a top priority for all economies as they work towards creating a prosperous and resilient future for current and future generations. This study empirically explores the important role of financial inclusion (FI), energy consumption, technological (TECH) innovation and environmental degradation in the economic growth of 13 selected developing Asian countries from 2000 to 2021. The feasible generalized least squares method is used for empirical examinations due to the nature of the data. The study focuses on three dimensions of FI: penetration, usage and availability of financial institutions. The results show that FI, energy consumption and TECH innovation encourage economic growth, whereas ecological footprint discourages economic growth in selected Asian countries. The empirical findings highlight the importance of promoting sustainable growth in Asia through enhanced FI, TECH innovation, sustainable energy practices and environmental conservation. Governments in these countries should prioritize strengthening the financial sector, investing in research and development and implementing effective policies to ensure a clean and green environment. This will lead to inclusive and environmentally responsible development that benefits both current and future generations in the region.

DNA‐rGO Aerogel Bioanodes with Microcompartmentalization for High‐Performance Bioelectrochemical Systems

AbstractBioelectrochemical systems (BES) have garnered significant attention for their applications in renewable energy, microbial fuel cells, biocatalysis, and bioelectronics. In BES, bioelectrodes are used to facilitate extracellular electron transfer among microbial biocatalysts. This study is focused on enhancing the efficiency of these processes through microcompartmentalization, a technique that strategically organizes and segregates microorganisms within the electrode, thereby bolstering BES output efficiency. The study introduces a deoxyribonucleic acid (DNA)‐based reduced graphene oxide (rGO) aerogel engineered as a bioanode to facilitate microorganism compartmentalization while providing an expanded biocompatible surface with continuous conductivity. The DNA‐rGO aerogel is synthesized through the self‐assembly of graphene oxide and DNA, with thermal reduction imparting lightweight structural stability and conductivity to the material. The DNA component serves as a hydrophilic framework, enabling precise regulation of compartment size and biofunctionalization of the rGO surface. To evaluate the performance of this aerogel bioanode, measurements of current generation are conducted using Shewanella oneidensis MR‐1 bacteria as a model biocatalyst. The bioanode exhibits a current density reaching up to 1.5 A·m⁻2, surpassing the capabilities of many existing bioanodes. With its abundant microcompartments, the DNA‐rGO demonstrates high current generation performance, representing a sustainable approach for energy harvesting without reliance on metals, polymers, or heterostructures.

A new wide input voltage DC-DC converter for solar PV systems with hybrid MPPT controller

The present working conventional power generation systems utilization is reducing day by day because of their demerits are more functioning cost, high carbon dioxide emission, more complexity in handling, and required high installation area. So, the current power generation company focuses on Renewable Energy Sources (RES) which are wind, tidal, and solar. Here, the solar power network is utilized for supplying electricity to the electrical vehicle battery charging system. The Solar photovoltaic (PV) modules supply nonlinear power which is not useful for automotive systems. To maximize the supply power of the solar PV system, an Adaptive Step Genetic Algorithm Optimized (ASGAO) Radial Basis Functional Network (RBFN) is utilized for tracking the working point of the solar PV module thereby enhancing the operating efficiency of the overall system. The features of this proposed hybrid Maximum Power Point Tracking (MPPT) controller are quick system dynamic response, easy operation, quick convergence speed, more robustness, and high operating efficiency when equalized with the basic MPPT controllers. The major issue of solar PV modules is low supply voltage which is increased by introducing the wide input voltage DC-DC converter. The merits of this introduced converter are low-level voltage stress on diodes, good quality supply power, high voltage gain, plus low implementation cost. Here, the introduced converter along with the AGAO-RBFN controller is analyzed by selecting the MATLAB/Simulink environment. Also, the proposed converter is tested with the help of a programable DC source.

Climate Literacy in the Age of Global Climate Change: A Critical Inquiry into Shaping Climate –Literate Society for a Sustainable Future

Climate Change is a multidimensional challenge in the twenty-first century. The challenges venting out of the consequences of climate change are mainly due to a lack of information and knowledge to combat it. It is important to build a climate-literate society to address and combat the consequences of ecological catastrophe. There is a need for cutting-edge knowledge on understanding the nuances of critical components of climate science, which is the need of the hour. Henceforth, climate literacy is an understanding of anthropogenic impact driven by human activities that have led to planetary crisis; cultivating ecological skills and thought processes, with a pragmatic vision of providing a tool to build a sustainable world in the era of climate change world. The role of educators and academic institutions in nurturing environmental stewardship becomes a vital for taking a step forward to a sustainable future in the cocoon of sustainable development goals. This paper will explore and address the vision of cultivating climate literacy as a framework for sustainable development and addressing climate resilience in the age of global climate change. The aim of the study is to identify the efficacy of Climate Change Education (CCE) initiatives and to trace few of the best practices and methods for developing a climate-literate society. As we introspect into the future outcome of the present study, it will envision climate literate society and decision-making processes at individual, institutional, and governmental levels for promoting sustainability and millennium development goals. Thus, it calls for action, emphasising the urgency of humanising climate literacy to empower current and future generations to contribute meaningfully to the global environmental sustainability and resilience effort.

Finding synergies between agroecology and industrial ecology toward sustainable agricultural systems

The question of how humans will co-create better food and agricultural systems is ex­tremely complex, and responses vary significantly due to experiences, worldviews, and values. Those of us working on this question typically agree that the goal is to realize systems that are equitable, just, minimize harm to, and ultimately support healthy ecosystems for current and future generations. I will refer to this goal as sustainability. My training is in industrial ecology and civil and environmental engineering, and my professional research focuses on questions of the climate and nutrient impacts associated with agriculture and food products as they are in our time, i.e., dominated by commodity crops. I was introduced to agroecology about 15 years ago while looking into ways to reduce nutri­ent runoff and improve soil and ecosystems, such as alternative cropping systems, integrated farming practices, permaculture, and more. Eventually, I learned of agroecology as a science, movement, and practice, which increased my interest to learn more. Both industrial ecology and agroecology, and the many branches within them, earnestly pursue facets of sustainability in agriculture, food, and other bio-based systems, and collaboration could lead to synergistic efforts. . . .

A Residential Building Extension Prototype to face Post-Pandemic Needs: Foreseen Challenges and Impacts

The COVID-19 pandemic highlighted the importance of outdoor spaces for maintaining physical and mental well-being. However, many urban residents lack private outdoor areas, which led to harmful health consequences during lockdowns. The research project aims to address and solve this issue by developing a physical/digital prototype called “X-TEND” that extends living space outdoors by attaching it to existing multi-story residential building facades. This prototype intends to promote healthier lifestyles, improving the well-being of individuals and positively impacts the urban surroundings aesthetics. X-TEND prototype uses a light, modular, and prefabricated approach for cost-effectiveness and environmental sustainability. It incorporates generative processes for structural and bioclimatic optimisation complemented by green building strategies to reduce environmental impact while maximising thermal and energy performance. Ultimately, X-TEND prototype contributes to a more sustainable built environment, fostering healthier and more liveable cities for current and future generations.

The Integration of Dual Evaluation and Minimum Spanning Tree Clustering to Support Decision-Making in Territorial Spatial Planning

Spatial planning, a policy instrument for creating sustainable environments that meet the needs of the current and future generations, has been implemented extensively worldwide. However, it is difficult for urban planners to thoroughly determine the spatial value of a territory and make informed decisions regarding the efficient utilization of regional resources in the real world. This study proposes a novel methodological framework for spatial pattern optimization that can guide future land use by integrating Minimum Spanning Tree (MST) clustering with a comprehensive evaluation system (dual evaluation). Furthermore, the validity of this framework is demonstrated through a case study of territorial spatial planning in Deyang, China. The findings indicate that (1) the methodological framework presented in this study offers valuable guidance for the spatial arrangement of territorial resources, especially in practical projects; and (2) the combination of dual evaluation and MST clustering can facilitate automatic regionalization to identify spatial clusters exhibiting functional similarity in terms of land use. By focusing on methodological advancements, this study concludes that the integration of dual evaluation (DE) and MST clustering not only simplifies the identification of optimal land-use patterns but also promotes a more systematic and efficient approach to support spatial planning.

Low Voltage Ride Through Control Strategy for a Two-Stage Grid-Tied Solar Photovoltaic System with Grid Faults

This paper investigates a low voltage ride-through (LVRT) control strategy for a two-stage grid-tied solar photovoltaic (SPV) system with line-to-ground (L-G) and double line-to-ground (L-L-G) faults. A proportional resonant (PR) controller controls the SPV inverter based on classical and reactive power oscillation-based reference current generating techniques. The proposed method injects reactive power as an ancillary service to provide voltage support and prevent power outages, reduces the DC component injection into the grid currents, and finally injects sinusoidal currents into the grid, avoid voltage oscillations in the DC-link and limit the inverter current by operating the boost converter in non-MPPT mode during L-G & L-LG faults. Experimental results for reference current generation using classical method and proposed method are compared to highlight the proposed controller’s ability to maintain power quality during faults.

Persistent Chirality-Induced Spin-Selectivity Effect in Circular Helix Molecules.

The spin-orbit coupling (SOC), the dynamics of the nonequilibrium transport process, and the breaking of time-reversal and space-inversion symmetries have been regarded as key factors for the emergence of chirality-induced spin selectivity (CISS) and chirality-dependent spin currents in helix molecules. In this work, we demonstrated the generation of persistent CISS currents in various circular single-stranded DNAs and 310-helix proteins for the first time, regardless of whether an external magnetic flux is applied or not. This new CISS effect presents only in equilibrium transport processes, distinct from the traditional CISS observed in nonequilibrium transport processes and linear helix molecules; we term it as the PCISS effect. Notably, PCISS manifests irrespective of whether the SOC is chirality-driven or stems from heavy-metal substrates, making it an efficient way to generate chirality-locked pure spin currents. Our research establishes a novel paradigm for examining the underlying physics of the CISS effect.

Species Scale and Primordial Gravitational Waves

AbstractThe species scale is a field‐dependent UV cut‐off for any effective field theory weakly coupled to gravity. In this letter, it is shown that in the context of inflationary cosmology, a detection of primordial gravitational waves will set an upper bound on the decay rate of the species scale. Specifically, this is derived in terms of the tensor‐to‐scalar ratio of power spectra of primordial perturbations. Given the targets of current and next generation experiments, it is shown that any successful detection would signify that this upper limit is of the order of unity, which is consistent with recent discussions in the literature.

Green architecture: Conceptualizing vertical greenery in urban design

This executive summary introduces the concept paper on Green Architecture, focusing specifically on the integration of vertical greenery in urban design. Green architecture, characterized by sustainable design principles and environmental consciousness, aims to enhance urban environments by incorporating vegetation into built structures. Vertical greenery, a key component of green architecture, involves the strategic placement of vegetation on vertical surfaces such as walls, facades, and rooftops. This concept paper explores the potential of vertical greenery to mitigate environmental issues in urban areas, improve air quality, reduce the urban heat island effect, and enhance biodiversity. The paper proposes a conceptual framework for conceptualizing vertical greenery in urban design, emphasizing the importance of integrating natural elements into the built environment. It discusses various strategies for implementing vertical greenery, including the selection of suitable plant species, design considerations for irrigation and structural stability, and the incorporation of greenery into urban planning processes. Moreover, the concept paper highlights the social and economic benefits of vertical greenery, such as improved health and well-being for residents, increased property values, and enhanced aesthetics of urban spaces. It also emphasizes the role of stakeholder engagement, interdisciplinary collaboration, and ongoing monitoring and evaluation in the successful implementation of vertical greenery projects. In conclusion, this executive summary outlines the significance of incorporating vertical greenery into urban design practices as a means to promote sustainability, resilience, and livability in cities. By embracing the principles of green architecture and integrating vertical greenery into urban landscapes, cities can create healthier, more vibrant, and environmentally sustainable communities for current and future generations. Keywords: Urban, Design, Green, Architecture, Vertical.

WHY GOOGLE GLASSES FAILED?

In this research paper we are basically trying to find out why Google Glasses failed as a product in the market. Google Glasses was launched back in 2012 as a product that created a lot of buzz in the market as “Wearable Smart Glasses”. But it never managed to effectively capitalise on the hype that surrounded the product and failed in capturing the market share and did not turn out as a money-making product. On the contrary, Google lost $895 million and incurred heavy losses and ultimately had to give up on the product. It failed to captivate the imagination of the people and people were not really interested in the product. When we dig deeper into the problem, we found several loopholes and flaws in the product, and in the basic business idea on the fundamental level. First of all, the designers of the idea and the product lacked the clarity as to whether the glasses would be considered as a fashionable device or just stand out as a utilitarian product. The problem was also with the price of the product, as this was so expensive that only the rich could afford and hence inaccessible to the masses and a limited target market. The people were also concerned with the privacy aspect as the current generation is quite conscious about their data being recorded and people did not really like this aspect of Google Glasses. People were even concerned with the safety of this product. People were not really great fans of the design of the glasses and generally regarded the product as uncool. Moreover, the grim problem of low battery life on the glasses was another major flaw. Nobody likes it, if they have to charge their product every now and then, it really drops the satisfaction level, and this happened with Google Glasses as well. The design of the glasses was unappealing and the glasses regularly faced heating and language issues. So overall these were the factors we found out that contributed in the product ending up as a huge failure in the market, despite the fact that it had a huge brand value as the likes of Google backing it up.

Analyzing Robustness of Automatic Scientific Claim Verification Tools against Adversarial Rephrasing Attacks

The coronavirus pandemic has fostered an explosion of misinformation about the disease, including the risk and effectiveness of vaccination. AI tools for automatic Scientific Claim Verification (SCV) can be crucial to defeat misinformation campaigns spreading through social media channels. However, over the past years, many concerns have been raised about the robustness of AI to adversarial attacks, and the field of automatic scientific claim verification is not exempt. The risk is that such SCV tools may reinforce and legitimize the spread of fake scientific claims rather than refute them. This paper investigates the problem of generating adversarial attacks for SCV tools and shows that it is far more difficult than the generic NLP adversarial attack problem. The current NLP adversarial attack generators, when applied to SCV, often generate modified claims with entirely different meaning from the original. Even when the meaning is preserved, the modification of the generated claim is too simplistic (only a single word is changed), leaving many weaknesses of the SCV tools undiscovered. We propose T5-ParEvo, an iterative evolutionary attack generator, that is able to generate more complex and creative attacks while better preserving the semantics of the original claim. Using detailed quantitative and qualitative analysis, we demonstrate the efficacy of T5-ParEvo in comparison with existing attack generators.

A spin current detecting device working in the drift-diffusion and degenerate regimes

<p>A semiconductor-based device working in the spin drift-diffusion regime and for probing the injected or generated spin current was considered.  The electric field effects on spin transport were analysed. A drift-diffusion equation for spin density was derived and contributions to the spin current were examined. By referring to the techniques of the spin current injection and generation, expressions for the spin current and spin-induced transverse Hall voltage arising from the injected or generated spin-polarized current were derived. The spin current and Hall voltage in dependences of the external electric field and temperature in the degenerate regime were studied. The device operated on the basis of with no external magnetic fields gives a voltage probe of the spin-induced Hall effect. Finally, a way of enhancing the spin current was explored.</p>

Quantifying the large contribution from orbital Rashba–Edelstein effect to the effective damping-like torque on magnetization

The generation of large spin currents, and the associated spin torques, which are at the heart of modern spintronics, has long been achieved by charge-to-spin conversion mechanisms, i.e., the spin Hall effect and/or the Rashba–Edelstein effect, intrinsically linked to strong spin–orbit coupling. Recently, a novel path has been predicted and observed for achieving significant current-induced torques originating from light elements, hence possessing weak spin–orbit interaction. These findings point out to the potential involvement of the orbital counterpart of electrons, namely the orbital Hall and orbital Rashba–Edelstein effects. In this study, we aim at quantifying these orbital-related contributions to the effective torques acting on a thin Co layer in different systems. First, we demonstrate in Pt|Co|Cu|AlOx stacking a comparable torque strength coming from the conversion due to the orbital Rashba–Edelstein effect at the Cu|AlOx interface and the one from the effective spin Hall effect in the bottom Pt|Co system. Second, in order to amplify the orbital-to-spin conversion, we investigate the impact of an intermediate Pt layer in Co|Pt|Cu|CuOx. From the Pt thickness dependence of the effective torques determined by harmonic Hall measurements complemented by spin Hall magneto-resistance and THz spectroscopy experiments, we demonstrate that a large orbital Rashba–Edelstein effect is present at the Cu|CuOx interface, leading to a twofold enhancement of the net torques on Co for the optimal Pt thickness. Our findings not only demonstrate the crucial role that orbital currents can play in low-dimensional systems with weak spin–orbit coupling but also reveal that they enable more energy efficient manipulation of magnetization in spintronic devices.