Physica Scripta

Many researchers have argued that humanity will create artificial general intelligence (AGI) within the next twenty to one hundred years. It has been suggested that AGI may inflict serious damage to human well-being on a global scale ('catastrophic risk'). After summarizing the arguments for why AGI may pose such a risk, we review the fieldʼs proposed responses to AGI risk. We consider societal proposals, proposals for external constraints on AGI behaviors and proposals for creating AGIs that are safe due to their internal design.

X-ray diffraction (XRD) is routinely used to characterise Ti alloys, as it provides insight on structure-related aspects. However, there are no dedicated reports on its accuracy are available. To fill this gap, this work aims at examining the benefits and limitations of XRD analysis for phase identification in Ti-based alloys. It is worth mentioning that this study analyses both standard and experimental Ti alloys but the scope is primarily on alloys slow cooled from high temperature, thus characterised by equilibrium microstructures. To be comprehensive, this study considers the all spectrum of Ti alloys, ranging from alpha to beta Ti alloys. It is found that successful identification and quantification of the phases is achieved in the majority of the different type of Ti-based alloys. However, in some instances like for near-alpha alloys, the output of XRD analysis needs to be complemented with other characterisation techniques such as microscopy to be able to fully characterise the material. The correlation between the results of XRD analysis and the molybdenum equivalent parameter (MoE), which is widely used to design Ti alloys, was also investigated using structural-analytical models. The parallel model is found to be the best to estimate the amount of β-Ti phase as a function of the MoE parameter.

Squeezed light generation has come of age. Significant advances on squeezed light generation have been made over the last 30 years—from the initial, conceptual experiment in 1985 till today's top-tuned, application-oriented setups. Here we review the main experimental platforms for generating quadrature squeezed light that have been investigated in the last 30 years.

Alena Tensor is a recently discovered class of energy-momentum tensors that provides mathematical framework in which, as demonstrated in previous publications, the description of a physical system in curved spacetime and its description in flat spacetime with fields are equivalent. The description of a system with electromagnetic field based on Alena Tensor can be used to reconcile physical descriptions. (1) In curvilinear description, Einstein Field equations were obtained with Cosmological Constant related to the invariant of the electromagnetic field tensor, which can be interpreted as negative pressure of vacuum, filled with electromagnetic field. (2) In classical description for flat spacetime, three densities of four-forces were obtained: electromagnetic, against gravity (counteraction to gravitational free-fall), and the force responsible for the Abraham-Lorentz effect (radiation reaction force). Obtained connection of Einstein tensor with gravity and radiation reaction force, after transition to curvilinear description, excludes black hole singularities. There was obtained Lagrangian density and generalized canonical four-momentum, containing electromagnetic four-potential and a term responsible for the other two forces. In this description charged particles cannot remain at complete rest and should have spin, their energy results from the existence of energy of magnetic moment and the density of this energy is part of the Poynting four-vector. The distribution of charged matter was expressed as polarization-magnetization stress-energy tensor, what may explain why gravity is invisible in QED. 3) In quantum picture, QED Lagrangian density simplification was obtained, and the Dirac, Schrödinger and Klein–Gordon equations may be considered as approximations of the obtained quantum solution. Farther use of Alena Tensor in unification applications was also discussed.

The solar system started to form about 4.56 Gyr ago and despite the long intervening time span, there still exist several clues about its formation. The three major sources for this information are meteorites, the present solar system structure and the planet-forming systems around young stars. In this introduction we give an overview of the current understanding of the solar system formation from all these different research fields. This includes the question of the lifetime of the solar protoplanetary disc, the different stages of planet formation, their duration, and their relative importance. We consider whether meteorite evidence and observations of protoplanetary discs point in the same direction. This will tell us whether our solar system had a typical formation history or an exceptional one. There are also many indications that the solar system formed as part of a star cluster. Here we examine the types of cluster the Sun could have formed in, especially whether its stellar density was at any stage high enough to influence the properties of today's solar system. The likelihood of identifying siblings of the Sun is discussed. Finally, the possible dynamical evolution of the solar system since its formation and its future are considered.

In this work, strange quark matter (SQM) and normal matter (NM) attached to domain wall (DW) matter distributions have been examined for locally rotationally symmetric (LRS) Bianchi-I space-time has been investigated. The model has been constructed in the framework of f(R, T) theory for f(R, T) = R + 2μT which is suggested as an alternative gravitation theory instead of Einstein's General Relativity Theory. Obtained modified field equations have been solved by using scale factors equation A = B^m come from the proportion of expansion scalar θ to shear scalar ϖ². SQM and NM are added to DW with the help of equations of state (EoS) ${p}_{m}=\frac{1}{3}({\rho }_{m}-4{B}_{c})$ and p_m = (γ − 1)ρ_m. Pressure and energy densities of all matter distributions have been obtained depending on cosmic time t and their effects decrease by the time. It is found that DW matter behaves like stiff matter due to attaining DW pressure equal to DW energy density p^DW = ρ^DW. Also obtained values of scale factors and some kinematic quantities give an expanding universe for the model. Energy conditions and kinematic quantities of the model have been examined in the last section. In addition, General Relativity solutions of the model have been attained by assuming μ = 0 in f(R, T) = R + 2μT. All solutions have been concluded in detail.

We present an alternative formulation of quantum mechanical angular momentum, based on spatial wavefunctions that depend on the Euler angles $\varphi ,\theta ,\chi$, and have an additional internal projection $n$. The wavefunctions are Wigner D-functions, ${D}_{\mathrm{nm}}^{s}(\varphi ,\theta ,\chi )$, for which the body-fixed projection quantum number $n$ has the unusual value $n=\left|{\boldsymbol{s}}\right|=\sqrt{s\left(s+1\right)}{\mathscr{=}}{\mathscr{s}}$, or $n=0$. We show that the states ${D}_{{\mathscr{s}}m}^{s}(\varphi ,\theta ,\chi )$ of elementary particles with spin $s$ give a gyromagnetic ratio of $g=2$ for $s\gt 0$, and we identify these as the spatial angular-momentum wavefunctions of known fundamental charged particles with spin. All known Standard-Model particles can be categorized with either value $n={\mathscr{s}}$ or $n=0$, and all known particle reactions are consistent with the conservation of its projection in the internal frame, and with internal-frame Clebsch-Gordan coefficients of unity. Therefore, we make the case that the ${D}_{{\rm{nm}}}^{s}(\varphi ,\theta ,\chi )$ are useful as spatial wavefunctions for spin. Some implications and new predictions related to the quantum number $n$ for fundamental particles are discussed, such as the proposed Dirac-fermion nature of the neutrino, the explanation of some Standard-Model structure, and some proposed dark-matter candidates.

First conceptualised in Olaf Stapledon's 1937 novel 'Star Maker', before being popularised by Freeman Dyson in the 1960s, Dyson Spheres are structures which surround a civilisation's sun to collect all the energy being radiated. This article presents a discussion of the features of such a feat of engineering, reviews the viability, scale and likely design of a Dyson structure, and analyses details about each stage of its construction and operation. It is found that a Dyson Swarm, a large array of individual satellites orbiting another celestial body, is the ideal design for such a structure as opposed to the solid sun-surrounding structure which is typically associated with the Dyson Sphere. In our solar system, such a structure based around Mars would be able to generate the Earth's 2019 global power consumption of 18.35 TW within fifty years once its construction has begun, which itself could start by 2040 using biennial launch windows. Alongside a 4.17 km² ground-based heliostat array, the swarm of over 5.5 billion satellites would be constructed on the surface of Mars before being launched by electromagnetic accelerators into a Martian orbit. Efficiency of the Dyson Swarm ranges from 0.74–2.77% of the Sun's 3.85 × 10²⁶ W output, with large potential for growth as both current technologies improve, and future concepts are brought to reality in the time before and during the swarm's construction. Not only would a Dyson Swarm provide a near-infinite, renewable power source for Earth, it would also allow for significant expansions in human space exploration and for our civilisation as a whole.

In this study, we focused on a FePtAu-C small-grain film specifically designed for very-high density perpendicular magnetic recording media, surpassing 1 Tbits/in² density. The film layer had a composition of Fe₄₇Pt₄₃Au₁₀-C40% with 7.2 nm thickness. It was deposited onto a silicon substrate with one 12 nm thick magnesium oxide sandwich-layer at 560 °C temperature. Notably, the film exhibited a perpendicular coercivity of 39 kOe. Based on transmission electron microscopy (TEM) analysis, the film small-grain size was determined to be approximately 8.2 ± 1.6 nm. Furthermore, our investigation revealed that the grain size of magnesium oxide sandwich-layer was about 12 nm, which was larger than that of FePt. As a consequence, the FePt small-grains were not directly influenced by magnesium oxide small-grains beneath them. Moreover, a more in-depth examination using high-resolution TEM imaging demonstrated outstanding L1₀ ordering within the thin-film, corroborated by texture examination conducted via x-ray diffraction (XRD). It is noteworthy that magnesium oxide sandwich-layer exhibited a polycrystalline structure, while the FePt growing on top of magnesium oxide occurred in an epitaxial manner.

The concept of the Fermi surface is at the very heart of our understanding of the metallic state. Displaying intricate and often complicated shapes, the Fermi surfaces of real metals are both aesthetically beautiful and subtly powerful. A range of examples is presented of the startling array of physical phenomena whose origin can be traced to the shape of the Fermi surface, together with experimental observations of the particular Fermi surface features.

In this study, we utilize photometric and kinematic data from Gaia DR3 and the ASteCA package to analyze the sparsely studied open clusters, King 2 and King 5. For King 2, we identify 340 probable members with membership probabilities exceeding 50%. Its mean proper motion components are determined as $({\mu }_{\alpha }\cos \delta ,{\mu }_{\delta })=(-1.407\pm 0.008,-0.863\pm 0.012)$ mas yr⁻¹, and its limiting radius is derived as 6.94${}_{-1.06}^{+0.22}$ arcminutes based on radial density profiles. The cluster has an estimated age of 4.80  ±  0.30 Gyr, a distance of 6586  ±  164 pc, and a metallicity of [Fe/H] = −0.25 dex (z = 0.0088). We detect 17 blue straggler stars (BSSs) concentrated in its core, and its total mass is estimated to be 356 ± 19M_⊙. The computed apex motion is $({A}_{o},{D}_{o})=(-14{2}_{.}^{\circ }61\pm {0}_{.}^{\circ }08,-6{3}_{.}^{\circ }58\pm {0}_{.}^{\circ }13)$. Similarly, King 5 consists of 403 probable members with a mean proper motion components $({\mu }_{\alpha }\cos \delta ,{\mu }_{\delta })=(-0.291\,\pm 0.005,-1.256\pm 0.005)$ mas yr⁻¹ and a limiting radius of 11.33${}_{-2.16}^{+5.45}$ arcminutes. The cluster's age is determined as 1.45  ±  0.10 Gyr, with a distance of 2220  ±  40 pc and a metallicity of [Fe/H] = −0.15 dex (z = 0.0109). We identify 4 centrally concentrated BSSs, and the total mass is estimated as 484 ± 22M_⊙. The apex motion is calculated as $({A}_{o},{D}_{o})=(-11{5}_{.}^{\circ }10\,\pm {0}_{.}^{\circ }09,-7{3}_{.}^{\circ }16\pm {0}_{.}^{\circ }12)$. The orbital analysis of King 2 and King 5 indicates nearly circular orbits, characterized by low eccentricities and minimal variation in their apogalactic and perigalactic distances. King 2 and King 5 reach maximum heights of 499  ±  25 pc and 177  ±  2 pc from the Galactic plane, respectively, confirming their classification as young stellar disc population.

The present report represents, the physicochemical characteristics of pure and Mn-substituted SnO₂ nanocrystals (NCs) [Sn_(1-x)Mn_xO₂ NCs, where x = 0, 0.05, and 0.10], synthesized using the co-precipitation technique. Structural characterization revealed that all the compositions possessed tetragonal crystal phase with space group $P{4}_{/2}{mnm}$ with no signature of impurities. Microstructural characterization depicted that the average grain size decreased from 34 nm to 22 nm with Mn doping in the host SnO₂. The appearance of 643 cm⁻¹ and 484 cm⁻¹ is attributed to O-Sn-O and Sn-O vibrations, which confirmed the formation of Sn_(1-x)Mn_xO₂ NCs. The electrical characterizations were conducted using Hall effect measurements and it was observed that doping of Mn in the crystal framework of host SnO₂ decreases the carrier concentration (n) from 5.73 × 10¹⁶ cm⁻³ to 3.36 × 10¹⁶ cm⁻³ whereas the mobility (μ) decreases from 5.18 cm² Vs⁻¹ to 2.35 cm² Vs⁻¹ thereby transforming the system from n-type behavior of pristine SnO₂ to p-type with Mn doping. The dielectric constant also decreases with increasing Mn concentration in the system. I-V characteristics show linear behavior with improved resistance with the addition of Mn to SnO₂.

Nd₂Fe₁₄B/α-Fe nanocomposite magnets are known for their superior theoretical energy products, but a significant challenge lies in eliminating harmful metastable phases, which often form during the crystallization process of amorphous materials. This study presents a strategy to simultaneously eliminate metastable phases and reduce grain sizes in Nd₂Fe₁₄B/α-Fe nanocomposites through non-equilibrium laser-heated processing with ultrafast heating rates. The technique is applied to ternary amorphous Nd_(7.5+x)Fe_(86.5-x)B₆ (x = 0, 1.5, 4.3) alloys. In Nd₉Fe₈₅B₆ alloys, an ultrafast heating rate (∼400 °C s⁻¹) during laser-heated annealing increases the short-range order (R_s) of the amorphous matrix from 0.52 nm to 0.57 nm. This also lowers the crystallization temperature and promotes a direct transformation from the amorphous phase to the stable phase, effectively suppressing the formation of metastable phases during crystallization. As a result, the saturation magnetization (M_s) increases from 1.59 T to 1.64 T. The refined grain sizes improve coercivity (H_ci) and the squareness of the demagnetization curve, which are attributed to the reduced crystallization temperature from 750 °C to 700 °C necessary to produce the Nd₂Fe₁₄B/α-Fe nanostructure. Further investigations into the crystallization behavior of amorphous alloys with varying Fe contents reveal that the inhibition of harmful metastable phases formation becomes more pronounced as the Fe content increases. These findings demonstrate an effective approach for mitigating metastable phase formation during the amorphous crystallization process, thereby enhancing the saturation magnetization of Nd₂Fe₁₄B/α-Fe nanocomposite magnets. This approach offers a pathway for developing high-performance nanocomposite magnets with high Fe content.

In this paper, we have theoretically investigated effects of certain electric confining potentials, hydrostatic pressure, and temperature on binding energies, photoionization cross-sections (PCS) and associated diamagnetic susceptibilities (DMS) in a GaAs spherical quantum dot. The potential profile considered here is the linear combination of the inverse lateral shifted parabolic potential and the inverse parabolic potential. Results show that the inverse lateral shifted parabolic potential enhances both binding energies and transition energies, while the inverse parabolic potential decreases the binding energies and transition energies. Photoionization occurs whenever the energy of incident electromagnetic radiation equals the transition energies. This implies that the two potentials can be used to tune PCS in SQDs, the inverse lateral shifted parabolic potential blueshifting the peaks of the PCS, while the inverse parabolic potential redshifting the peaks. The results also reveal that rise in temperature increases transition energies while it decreases binding energies. On the other hand, increase in pressure decreases transition energies while it enhances binding energies. This implies that, in the event that SQDs are incorporated in nanodevices, increase in temperature (possibly due to Joule heating) may detune SQDs. Thus, pressure of precise magnitude can be applied to counter the effects of temperature on transition energies, thereby ameliorating the temperature-induced detuning.

Water-lubricated bearings (WLBs) have gained extensive application as support bearings in marine propulsion systems owing to their environmental compatibility and elimination of oil leakage risks. However, prolonged operation of WLBs inevitably leads to wear of the friction interface, consequently altering the bush profile. Given that the transient characteristics of WLBs are highly sensitive to variations in bush profile, such wear-induced modifications inevitably induce significant changes in the transient trio-dynamic behaviors of WLBs, particularly during the start-up phase. This study investigates the impact of wear parameters on the dynamic characteristics of bearings by developing a mathematical model for the transient startup of worn WLBs. A comparison of the calculated data with the relevant experimental data confirms the validity of the model. Simulation results reveal that increased wear depth facilitates more rapid attainment of maximum hydrodynamic force in WLBs. However, when wear depth exceeds the optimal value (corresponding to a dimensionless wear depth of 0.1 in this study), the achievable maximum hydrodynamic force is significantly reduced. Specifically, the maximum hydrodynamic pressure decreased from 2.3 MPa to 1.375 MPa, representing a 40% reduction. Furthermore, both positive and negative wear deviation angles were found to adversely affect bearing startup performance. Optimal start-up characteristics were observed at a wear deviation angle of 0°. These findings provide valuable theoretical insights for the structural design and performance optimization of water-lubricated bearings in marine applications.

Despite their many advantages, the widespread application of magnesium (Mg) alloys is hindered by their high corrosion rates and poor ductility and formability. One effective method for enhancing both the corrosion resistance and mechanical properties, such as ductility, of Mg alloys is through alloying with Rare Earth (RE) elements. These elements have recently garnered significant attention due to their beneficial properties, including an electrode potential similar to that of Mg and their capacity to refine grain size, which contributes to reduced corrosion rates and enhanced alloy strength. This paper explores the common forms of Mg corrosion and elucidates the mechanisms by which RE elements improve corrosion resistance and mechanical behavior in Mg-RE alloys. It also provides a detailed analysis of how each RE element alters the corrosion behavior of Mg-based alloys. By integrating RE elements, it is possible to control corrosion and improve mechanical properties through mechanisms like solid solution strengthening, grain refinement, and the formation and distribution of secondary phases.

Heat transfer enhancement has become an important research area to improve the efficiency of thermal systems. This chronological review focuses on approaches for heat transfer enhancement by incorporating inputs into strategies. An in-depth review has been carried out with inserts such as twisted tapes, turbulators, vortex generators, dimple surfaces and porous materials to improve heat transfer in a variety of applications like heat exchangers, renewable energy devices, automotive systems and electronic cooling systems. A comprehensive literature review across several decades was conducted to examine the progress in improving heat transfer efficiency. Various numerical, analytical and experimental methods used in the study were examined to correct the processes and effects of different insert designs. The study includes various insert geometries, structures and materials providing a detailed analysis of the state-of-the-art in heat transfer enhancement. The review highlights key findings from studies of various inputs and their effects on heat transfer enhancement. It provides insight into efficiency metrics such as the Nusselt number, coefficient of heat transfer and pressure drop associated with each insertion method. In addition, the chronological presentation allows trends and improvements to be identified in insert-based heat transfer enhancement over the years. The results in various applications show the effectiveness of certain insert geometries and configurations in improving heat transfer performance. This chronological analysis provides a comprehensive overview of the progress in heat transfer enhancement through the use of different approaches. Knowledge gathered from various studies demonstrates the potential of insert-based methods to significantly improve the thermal conductivity of various thermal systems. Insights gained from this study can guide future research efforts, contributing to efficient and sustainable heat transfer technologies that have been developed. The conclusion highlights the importance of continued research in this area to address the growing challenges of thermal management and energy efficiency.

Two-dimensional (2D) Boron Carbon Nitride (BCN) has recently gained significant attention as a convoluted ternary system owing to its remarkable capability to exhibit a wide range of finely tunable physical, chemical, optical, and electrical properties. In this review, we discuss a variety of stable structure forms of BCN nanosheets. In addition, this review provides recent approaches for synthesizing BCN nanostructures, and properties of BCN derivatives. BCN is a promising material for sustainable energy and energy storage devices. Since BCN application is a challenge in the field of energy, we present potential applications of BCN in the field of energy including supercapacitors and batteries, wastewater treatment, electrochemical sensing, and gas adsorption.

The widespread application of synthetic dyes across industries poses significant environmental problems, particularly concerning with degradation of water quality. Concerning the possible solutions, copper oxide (CuO) considered as a feasible candidate. CuO a p-type heterogeneous semiconductor with a bandgap of 1.2–2.71 eV, It is a reasonable choice and widely studied photocatalyst for addressing such challenges. The functionality of CuO deteriorated, when the wavelength exceeded the UV–visible region. In this manner difficulties associated with reproducibility and reusability, as well as rapid electron–hole recombination, prevent the widespread application of this technology. In an attempt to eliminate this defect, researchers have been investigating strategies to activate CuO under visible light, with one promising approach being carbon nanomaterials such as graphene to form carbon-CuO composites. The unique properties of graphene, i.e., its higher surface area and excellent electron mobility, make it a remarkable candidate for the enhancement of CuO photoactivity. This study highlighted the recent progress in the synthesis of graphene-based CuO photocatalysts, with the main characteristic of extending the light absorption capacity of CuO into the visible spectrum. It reveals achievements in material innovations and applications, with a focus on photocatalytic. It has been observed from the documented studies, catalysis is considered as next generation emerging field for the researcher.

Within a decade, the power congversion efficiency (PCEs) of metal-halide perovskite solar cells (PSCs) moves upward from 3.9% to 25.7%, making them competitive with current state-of-the-art silicon-based counterparts. This steepest growth of the PCEs suggests that the commercialization of this technology might be easing the energy transition from fossil fuel to renewable energy. However, a wide range of factors restrict the commercial viability of PSCs like their toxicity and instability. A crucial and difficult task in the field of PSCs is the replacement of Pb-based perovskite with non-toxic and eco-friendly material while maintaining high-performance with improved stability. Cs₂AgBiBr₆ halide double perovskites (HDP) material seems to be very promising in this regard. This article reviews the recent progress in Cs₂AgBiBr₆ double PSC devices, especially fabrication techniques including the advancement of its efficiency and stability. Here, the evolution of Cs₂AgBiBr₆ towards the application and fabrication of PSCs has also been discussed. This study also analyzed the impact of numerous environmental stresses, such as mechanical, thermal, and optical stresses including the potential prospects in the case of Pb-free PSCs.

Preformed helical fittings play an indispensable role in ensuring the safe and stable operation.
Due to factors such as the material of the strands, environmental temperature, number of strands, and pitch, preformed helical fittings inevitably experience uneven heating during operation, which can cause localized softening of strands, leading to warping or even fracture. Therefore, studying the temperature rise characteristics of preformed helical fittings is crucial for ensuring the safety of power transmission lines. This paper derives the general parametric equations for preformed helical fittings used in three-dimensional modeling, and simplifies the contact conditions, establishing a three-dimensional multi-electrode simulation model to effectively simulate and quantify the contact between the strands and the conductor. Studying the temperature distribution of preformed helical fittings under various strand materials, environmental temperatures, number of strands, and pitches, it was found that the electrical conductivity is the primary factor influencing temperature rise characteristics and preformed helical fittings made of high-conductivity materials can effectively suppress temperature rise at contact points, while strand fracture may lead to increased temperatures at the rupture site, further exacerbating faults. This research provides valuable insights into the normal operation and maintenance of preformed helical fittings in power transmission lines.

Due to excellent pseudo-random performance, chaotic systems are often applied in the fields of cybernetics, cryptology. However, many chaotic systems have poor chaotic property e.g., narrow output range and lower complexity. For a pseudo-random number generator (PRNG) which can output pseudo-random number signal (PRNS), all these have negative effects on its practical application. To better solve these problem, this research designs a novel two-dimensional memristive boosting chaotic map (2D-MBCM). Along with several 2D discrete systems, 2D-MBCM has advantages in both generation time with sequence and system performance, it is of great significance for reducing the computing costs. Finally, by using field-programmable gate array (FPGA) platform, the boosting signals of 2D-MBCM are realized. The experiment result reflects the viability of its engineering application.

Current system-on-chips need robust, economical SRAM cells since energy sources are limited and technology is scaling. Hence, a resilient, delay and energy-optimized 11T CNTFET SRAM design is suggested in this analysis. The suggested High – Performance, Low – Power 11 Transistors (HPLP11T) CNTFET SRAM design features a resilient interlinked design featuring a conventional inverter paired with a cascaded CNTFET transistor, along with a Schmitt-based inverter that utilizes a pull-up transistor of twice the normal length. Isolating internal memory units from the read path completely eradicates read disturbance Additionally, employing a write-assist technique, the writing process executes in a pseudo-differential manner using a write bit line and a control signal. To assess the efficacy of the suggested HPLP11T CNTFET SRAM design, it is evaluated against alternative existing 11T SRAM cells through simulation conducted using the HSPICE tool, employing the Stanford University 32 nm CNTFET technology. The evaluation was conducted under extreme conditions, considering a 0.9 V supply voltage and accounting for challenging manufacturing processes, voltage fluctuations, and temperature variations (PVT). The intended HPLP11T CNTFET SRAM design demonstrates a write power of 1.584 nW, hold power of 4.563 nW, read power of 0.00457 µW, WSNM of 450 mV, HSNM of 360.8 mV, RSNM of 360.8 mV, write delay of 0.2724 ns, and read delay of 0.0454 ns. The proposed HPLP11T CNTFET SRAM cell demonstrates efficiency and suitability for Internet of Things (IoT) devices due to its low power consumption, high speed, and compatibility with microcontrollers. This is attributed to the inherent properties of CNTFETs, which offer high electron mobility and low leakage currents, leading to reduced power consumption and enhanced performance. Additionally, the design of the HPLP11T SRAM cell incorporates a read-decoupled approach and a Schmitt-trigger inverter, further improving stability and power efficiency, making it well-suited for IoT applications.

In this study, a transformation solution of high-order linear fractional differential equations is provided using Riemann-Liouville and Caputo fractional derivatives. To achieve this objective, HK transformed fundamental mathematical functions before outlining its salient characteristics were developed. Afterward, the fractional formula of HK transform was derived for both fractional calculus fractional integral and fractional derivative. Then the exact solution of an example of a fractional differential equation was found. This paper provided several numerical issues and solved them by strict stepwise solutions to illustrate the effectiveness of HK transform. The results demonstrate that the original HK Transform has been introduced provides correct solutions for fractional differential equations of multiple higher order without the need for tedious calculations.

The increasing demand for cost-effective, lightweight, and high-performance electromagnetic wave absorbers has driven development of advanced materials. Herein, we report the successful synthesis of cobalt/nitrogen doped noodles-like carbon nanotubes (Co/NCNT) composites through a straightforward one-step carbonization process. The unique noodles-like morphology of the Co/NCNT composites significantly enhances the electromagnetic wave absorption performance, exhibiting remarkable reflection loss of -76.6 dB in thickness of 3.35 mm, and effective absorption bandwidth of 5.56 GHz. The Co/NCNT composites exhibit good electromagnetic wave absorption performance across the C, X, and Ku frequency bands. Detailed investigations reveal that the outstanding performance of Co/NCNT composites is attributed to the formation of conductive networks and numerous heterogeneous interfaces, which enhance dielectric loss. Additionally, the presence of magnetic Co nanoparticles contributes to achieving optimal impedance matching. Moreover, the Co/NCNT composites demonstrate the ability to effectively reduce the radar cross-section by CST simulation, further highlighting their potential applications in microwave absorption and electromagnetic interference mitigation.

In this paper, we have theoretically investigated effects of certain electric confining potentials, hydrostatic pressure, and temperature on binding energies, photoionization cross-sections (PCS) and associated diamagnetic susceptibilities (DMS) in a GaAs spherical quantum dot. The potential profile considered here is the linear combination of the inverse lateral shifted parabolic potential and the inverse parabolic potential. Results show that the inverse lateral shifted parabolic potential enhances both binding energies and transition energies, while the inverse parabolic potential decreases the binding energies and transition energies. Photoionization occurs whenever the energy of incident electromagnetic radiation equals the transition energies. This implies that the two potentials can be used to tune PCS in SQDs, the inverse lateral shifted parabolic potential blueshifting the peaks of the PCS, while the inverse parabolic potential redshifting the peaks. The results also reveal that rise in temperature increases transition energies while it decreases binding energies. On the other hand, increase in pressure decreases transition energies while it enhances binding energies. This implies that, in the event that SQDs are incorporated in nanodevices, increase in temperature (possibly due to Joule heating) may detune SQDs. Thus, pressure of precise magnitude can be applied to counter the effects of temperature on transition energies, thereby ameliorating the temperature-induced detuning.

The use of CO₂ to partially replace traditional propellants in electric propulsion (EP) offers cost-effectiveness and good performance. This study investigates the impact of CO₂/Xe mixing ratios on Kaufman ion thruster plume characteristics through experiments. The plume characteristics of a Kaufman ion thruster are studied under different mixing flow rates and anode currents, while the underlying mechanisms of plasma formation in the mixed-medium thruster are explored. Results show that increasing the anode current and Xe flow rate promotes plasma generation, reduces electron temperature, and increases ion density. The addition of small amounts of CO₂ in the discharge chamber enhances thruster performance by reducing beam divergence, increasing ion density, and minimizing charge-exchange (CEX) ion reflux. However, further increases in CO₂ flow rate leads to deterioration in plume characteristics. An optimal CO₂/Xe mixture ratio of 1:1 under the tested conditions is demonstrated, which yielded superior beam performance characteristics.

Bohmian mechanics is an alternative formulation of quantum mechanics that maintains the notion of a well-defined trajectory governed by the wave function. The extra potential in this framework called quantum potential plays an important role in determining the dynamics of the Bohmian trajectory. In this study, we examine numerically the characteristics of a rational frequency system near a moving nodal point and how quantum potential plays an important role in generating chaotic motion for a specific mixture of wavefunction amplitudes. We show the transition from a regular to a chaotic trajectory when there is an abrupt change of quantum potential near the nodal point. This phenomenon occurs in the centre where the value of quantum potential is much higher than classical potential.

Deposition penetration depth into nanofibrous materials is a crucial but underexplored parameter for their modification using low-pressure plasma polymerisation. This work studies it using Monte Carlo simulations and two analytical approaches, a classic continuum diffusion model and a new abstract discrete model, which is fully solvable using the method of generating functions. The discrete model represents the material as a stack of cells with no further geometry and is only characterised by the sticking coefficient η of film-forming species. The models are used to investigate other properties, such as directional coverage of fibres by the deposited film, anisotropy of the mean free path in the nanofibrous material, or the effective sticking coefficient of the material as a whole. The two very different analytical approaches are found to complement each other. When the derived expressions are compared with Monte Carlo results, we find that the discrete model can provide surprisingly relevant formulae despite the very high level of abstraction. The clearest example is the sticking coefficients of the material as a whole, for which the discrete model achieves almost perfect agreement. The other two properties require dimensional scaling factors. It shows that certain aspects of the process are fundamental and mostly independent on details of the interactions and that the dependencies on the sticking coefficient are in some sense separable. By combining the analytical and Monte Carlo results we can also obtain elementary practical formulae for the studied quantities as functions of the sticking coefficient and/or porosity. They are directly applicable to the deep penetration of low-η species or deposition of thin coatings and can be used as local description in more complex cases.

This study reports the generation of dissipative soliton resonance (DSR) mode-locked pulses in an erbium-ytterbium doped fiber laser using a hybrid configuration combining graphene oxide/zinc oxide (rGO/ZnO) nanocomposite on an arc-shaped fiber as a saturable absorber (SA) with a nonlinear amplified loop mirror (NALM). Implementing the hybrid configuration gave an output spectrum with center wavelength and signal-to-noise ratio (SNR) of 1564 nm and 55 dB respectively. The hybrid setup generates 80 ns pulses with a pulse energy of 99.51 nJ. The system is very stable over time. This study highlights the performance of hybrid configuration in enhancing the generation of DSR mode-locked pulses that could be useful for practical applications in optical technologies.

Bragg reflection waveguides (BRW) enable the generation of photon pairs in non-birefringent AlGaAs through spontaneous parametric down conversion (SPDC). Furthermore, the development of an electrically driven laser source from a passive BRW by introducing a suitable doping profile and an active region allows the simultaneous lasing of the pump field and the SPDC process within the same cavity. Here, we present an optimized design of a BRW to allow lasing at 775 nm and simultaneous conversion into photon pairs at 1550 nm. Based on the computed modes at 775 nm and 1550 nm, the non-linear emission characteristics of both SPDC and second harmonic generation of the proposed device is calculated. The design is particularly optimized regarding the monolithic integration of a distributed Bragg reflector (DBR) section to stabilize the laser wavelength. This is necessary because SPDC is highly sensitive to the pump wavelength. By using an eigenmode expansion approach, we calculate the reflection spectra of a 1 mm long, 9th order surface grating in dependence of various parameters. We demonstrate that a peak reflectivity of  > 80% can be achieved with technologically feasible etch depths and groove widths. This paves the way for the promising application of DBR surface gratings for the selection of the pump wavelength for the SPDC process in BRW lasers, with the objective of improving the photon output.

Overactive bladder (OAB) significantly affects an individual's quality of life by disrupting daily routines and social interactions. The hallmark symptom of OAB is a sudden, uncontrollable urge to urinate, often resulting in involuntary leakage. Diagnosing OAB is challenging due to the subjective nature of symptom reporting and the absence of definitive biomarkers. Existing diagnostic methods, such as urodynamic testing and symptom questionnaires, provide valuable insights but often lack conclusive reliability. This research leverages a data-driven approach to diagnose and predict the severity of OAB symptoms using comprehensive questionnaire data. Participants of varying ages provided demographic information, medical history, and details such as urination frequency. OAB severity was classified into three levels: no OAB, mild OAB, and moderate OAB, reflecting an increasing intensity of symptoms. The collected data were used to train multiple machine learning (ML) models, including support vector machine (SVM), artificial neural networks (ANN), linear discriminant analysis (LDA), and random undersampling boosted (RUSBoost). Model performance was evaluated using K-fold cross-validation (K = 5 and 10), measuring accuracy, recall, and F1 score to ensure generalizability. Among the models, SVM achieved the highest accuracy, with a 10-fold cross-validation accuracy of 93.33%. To address limitations such as small dataset size and class imbalance, the synthetic minority oversampling technique (SMOTE) was applied, further enhancing model performance. Explainable artificial intelligence (XAI) techniques were also implemented, showing how individual features influenced model predictions. This eliminated the need for manual intervention by uncovering intricate patterns in symptom data and making the diagnostic process more accessible and interpretable. This study underscores the potential of integrating machine learning into OAB diagnosis. The results demonstrate that questionnaire-based predictions of OAB severity are highly accurate and cost-effective, surpassing the performance of human experts. This approach offers a promising solution for enhancing patient care and streamlining OAB management by reducing diagnostic costs and improving clinical decision-making.

Phase singularity beams are closely associated with orbital angular momentum (OAM) and hold significant applications in optical communication. The screw-edge dislocations beams, a type of phase singularity beams, serve as the research object in this paper, which delves into the propagation characteristics of screw-edge dislocations beams in turbulent atmospheric conditions. The study examines the effects of turbulence intensity on the spiral spectrum characteristics and channel capacity variations during beam propagation. The findings reveal that at the source plane, screw-edge dislocations beams exhibit two OAM modes with equal detection probabilities. During propagation through turbulent atmosphere, the detection probabilities of these two OAM modes decrease with increasing transmission distance under both strong and moderate turbulence, while, at the same transmission distance, remaining equal in strong turbulence. Nonetheless, under weak turbulence, the detection probability of one OAM mode gradually increases while that of the other decreases. Additionally, the channel capacity of screw-edge dislocations beams decreases with declining inner scale of turbulence and generalized exponential parameter under strong and moderate turbulence, while the channel capacity exhibits minimal decrease with increasing transmission distance under weak turbulence. These results provide valuable guidance for the application of OAM in optical communication.

We introduce a new method to derive solutions of the Dirac equation in external static fields that have a direct connection to classical physics. Using it, we derive new analytic solutions of the Dirac equation in a magnetic field, which reproduce the motion of relativistic classical particles. We also generalize this method to the case of crossed electric and magnetic field.

Assuming the beam spectrum at the accelerator output follows a Gaussian distribution and its attenuation in air is described by a Landau distribution, the ill-posed problem of electron energy spectrum reconstruction using depth-dose distribution was reduced to finding the electron spectrum at the phantom surface as a convolution of the Landau and Gaussian distributions. The algorithm proposed in the study uses the experimentally measured depth dose distributions generated by Varian TrueBeam medical accelerator operating at 6 MeV and 9 MeV modes in water-equivalint and aluminium phantoms and reconstructs the electron spectra in targeted materials. The algorithm uses reference depth dose distributions from monoenergetic electrons calculated using Geant4 toolkit. It was found that the spectra reconstructed using experimental depth dose distributions in solid water and aluminium differ by less than 5%, and reconstructed depth dose distributions corresponding to the reconstructed spectra deviate from experimentally measured ones by no more than 5%.