Gradient Line Research Articles

Self-floating Janus hydrovoltaics for sustainable electricity generation

Water is widely available in nature that attracts increasing interesting in simulating transpiration effect to induce the electricity. However, it faces great challenges in establishing continues moisture gradient rather than periodic wetting behaviors. Here, we propose a self-floating Janus generator containing the hydrophilic and hydrophobic regions to induce the continues electricity. The self-floating and hydrophilic behavior ensures a continuous water supply. The asymmetric Janus structure forms a distinct wet/dry interface to create a significant water gradient with evaporation equilibrium state. At wetting region, the electric double layer (EDL) is formed due to the interaction of water and carbon black particles. Attributed to the large water gradient and fast contact line evaporation, proton accumulates across the capillary front that induces a potential difference. As a result, the Janus generator achieves 0.46 V open circuit voltage lasting for 40 h. It also demonstrates the potential applications of Janus generator in power supply, moisture detection and sweat monitoring et al. The proposed Janus generators show great potential in ocean energy development and be of great significance to the sensing of rescue signals in the sea.

Stable homology isomorphisms for the partition and Jones annular algebras

We show that the homology of the Jones annular algebras is isomorphic to that of the cyclic groups below a line of gradient 12\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\frac{1}{2}$$\\end{document}. We also show that the homology of the partition algebras is isomorphic to that of the symmetric groups below a line of gradient 1, strengthening a result of Boyd–Hepworth–Patzt. Both isomorphisms hold in a range exceeding the stability range of the algebras in question. Along the way, we prove the usual odd-strand and invertible parameter results for the Jones annular algebras.

Method to determine instantaneous transient responses in pressurized pipes from transfer functions and state space for evaluation of leak signals

This article addresses the impact of transient pressure anomalies in hydraulic systems, triggered by the opening or closing of valves or pumps, instantly disturbing the line of hydraulic gradient (LGH). This variation in pressure has significant consequences both in hydraulic and structural terms for water networks. Most of the existing techniques to detect transients in water distribution systems use asynchronous methods, generating timeless information that limits the response capacity in critical situations. Therefore, an automatic transient detection system based on the Internet of Things (IoT) is proposed, capable of identifying overpressure or underpressure pulses in soft real-time, activating alarms to facilitate decision-making. This approach helps maintain the safety of the water distribution system and prevent leaks in the network. Furthermore, a model of the transient behavior of pressure and flow is presented by linearizing the water hammer equations from the Laplace transform, thus generating a transfer function that describes the algebraic relationship between the outlet and inlet of the hydraulic system.•The transient analysis of the hydraulic system prototype underscores its high sensitivity to initial conditions, attributed to turbulence. This observation suggests the possible presence of a dynamic strange attractor related to water hammer phenomena in pressure pipes.•The methodology involving transfer functions and state-space models enables the assessment of how leaks impact the transient responses of the system, including the magnitude, duration, and frequency of disturbances generated by them.•The proposed method introduces a dynamic transfer function capable of identifying instantaneous changes over time in terms of flow and pressure.

A Robust Distributed Algorithm for Solving the Economic Dispatch Problem with the Penetration of Renewables and Battery Systems

In the field of energy networks, for their effective functioning, it is necessary to distribute the required load between all online generating units in a proper way to cover the demand. The load schedule is obtained by solving the so-called Economic Dispatch Problem (EDP). The EDP can be solved in many ways, resulting in a power distribution plan between online generating units in the network so that the resulting price per unit of energy is minimal. This article focuses on designing a distributed gradient algorithm for solving EDP, supplemented by models of renewable sources, Battery Energy Storage System (BESS), variable fuel prices, and consideration of multiple uncertainties at once. Specifically, these are: time-variable transport delays, noisy gradient calculation, line losses, and drop-off packet representations. The algorithm can thus be denoted as robust, which can work even in unfavorable conditions commonly found in real applications. The capabilities of the presented algorithm will be demonstrated and evaluated on six examples.

Problem Of Ugliness Several Arguments For God's Unbeauty Creation

Beauty is in fact fundamental to understanding of divine being. Beauty informs of God’s perfections. Within Qur’an, the principle of tawhid which is that God is the Creator of the heavens is one Islamic metaphysical basis for the integration of the Greek heritage and Islamic revelation The problem in ugliness, especially ugliness in God's creation, raises questions about God's ability to create beautiful things. This study aims to deepen the understanding of imperfections in God's creation, which emerge the idea of bridging the gaps that are not yet well connected between God's most beautiful statement and His creation which is not all beautiful. Using a theological approach, this paper describes three problems not to deny that God is beautiful and loves beauty. First, God is Most Beautiful, and His manifestations in His creation are limited. Second, the formal imperfections in His creation were not created not to confront one another but instead are in a straight gradient line. Third, the physical imperfection is not interpreted as a limitation of God (finitism) but a message to His creatures

A truncated three-term conjugate gradient method with complexity guarantees with applications to nonconvex regression problem

In this paper, a truncated three-term conjugate gradient method is proposed for nonconvex unconstrained optimization. At each iteration, the search direction generated by this method is sufficiently descent independent of any line search. We investigate its global convergence with Wolfe line search under the standard assumptions. Moreover, we present its complexity analysis under the objective function with the Lipschitz continuously gradient and Armijo line search which implies that the proposed method is also globally convergent with Armijo line search. A remarkable point about its complexity is that the proposed method possesses the same complexity order as the classical gradient descent method without any restart strategy. Finally, the proposed method is applied to solve the nonconvex robust regression problems. Numerical results show that the proposed method is efficient.

Microanatomical lipid niche controls intestinal memory B cell migration and effector function

Abstract Enteric infections are a leading global burden, yet few oral vaccines elicit long-lasting immunity and prevent disease, likely due to our lack of understanding of intestinal immunological memory. Long-lived memory B cells can be rapidly reactivated to differentiate into plasma cells, thus further increasing antibody titers and mediating host protection. Such long-term protection requires memory B cells to migrate and persist in sub-anatomical niches within secondary lymphoid organs. While survival niches have been described for memory B cells in lymph nodes and spleen, no niche have been identified in mucosal lymphoid organs, such as Peyer’s patches (PPs). Here, we show that memory B cells require positioning in the PP subepithelial dome (SED) for maintenance and effector function. In PPs, memory B cells express the migratory receptors EBI2, which binds the oxysterol 7alpha, 25-hydroxycholesterol, and CCR6, which recognizes the chemokine CCL20. Both ligands are present in PPs and drive memory B cell migration in vitro. Conditional removal of EBI2 from memory B cells, either in a constitutive or acute fashion, alters their zonation in PPs, reduces their persistency, and impairs their antigen-specific response. While most memory B cells in PPs are IgA+, IgA B cell receptor expression is dispensable for memory B cell positioning in the SED. Using conditional mice for the enzymes generating the oxysterol gradient and cell specific Cre lines, we are currently mapping the cellular and metabolic requirements for EBI2 dependent memory B cell maintenance and effector function in PPs. Understanding the mechanisms for memory B cell persistence is fundamental to our understanding of the intestinal B cell memory response against pathogens. Previously supported by training grants from NIH (5 T32 AI 132152-2, 5 T32 AI 007349-29)

Analysis Of Spearman Rank Correlation & Linear Regression Of Atmospheric Stability And Cloud Tops Temperature Of Himawari-8 IR Satellite Images (Case Study Of Hail On May 22, 2022)

This research is based on cases of hail that caused flooding in Binjai City on May 22, 2022. This study aims to see the correlation and regression of the Atmospheric Stability index value on cloud top temperature data from the Himawari-8 satellite imagery. So that the ERA-5 reanalysis data can be used to obtain cloud top temperatures in predicting hail events. The indices used in this study are CAPE, KI and TTI. The data used is located in Binjai City with correlation testing from 00UTC – 24UTC on May 22, 2022. Supported data is used in the form of sea surface temperature and wind conditions and looks at the causes of hail at the research location. The method used is Spearman's rank correlation with the results obtained in the form of a correlation value at the K index of -0.651, a correlation of the TT index of -0.563, and a correlation of the CAPE index of -0.348. The simple linear regression results also show a negative gradient line. This shows that the increase in the value of the stability index is in line with the decrease in cloud top temperature. So that the stability index data can be used as a benchmark in estimating cloud top temperatures in the case of convective cloud formation which causes hail.

Diastolic compression device aimed at stopping refluxing flow

Theoretical concept of a diastolic compression device is presented. The device could have a form of a pneumatic cuff or a rubber sleeve. Its objective is to exert external pressure below the knee, which would compress the great saphenous vein during the diastolic phase of the calf pump activity, and hinder thereby the saphenous reflux and the occurrence of ambulatory venous hypertension. Based on the results of venous pressure measurements, it is supposed that pressure of about 35 mm Hg would be able to fulfill this therapeutic aim. If tolerated and accepted by the patients, the device could offer, in addition to the current invasive methods and compression stocking therapy, a simple conservative, nonetheless effective treatment of primary varicose veins. It would keep the dividing line of the ambulatory pressure gradient below the knee, as is the case with healthy people, and prevent thereby the progression of the disease. In addition, this conservative method would preserve the great saphenous vein for possible use as a bypass graft in the future.

A unifying view of modal clustering

AbstractTwo important non-parametric approaches to clustering emerged in the 1970s: clustering by level sets or cluster tree as proposed by Hartigan, and clustering by gradient lines or gradient flow as proposed by Fukunaga and Hostetler. In a recent paper, we draw a connection between these two approaches, in particular, by showing that the gradient flow provides a way to move along the cluster tree. Here, we argue the case that these two approaches are fundamentally the same. We do so by proposing two ways of obtaining a partition from the cluster tree—each one of them very natural in its own right—and showing that both of them reduce to the partition given by the gradient flow under standard assumptions on the sampling density.

On the Evolution of the Optimal Design of WDS: Shifting towards the Use of a Fractal Criterion

Several researchers have proposed methodologies for addressing the problem of designing optimal water distribution systems. Metaheuristic approximations are studied the most due to the vast solution space. In search of reducing computational time, the Non-dominated Sorting Genetic Algorithm II (NSGA-II) has been tested with retrofitting from the Optimal Power Use Surface (OPUS) methodology. A previous study demonstrates how OPUS significantly improves the results since it seeks to reduce energy losses in the network, in order to approximate minimum-cost designs using fewer hydraulic executions. However, more research is still needed to determine applicable hydraulic criteria that allow an enhanced comprehension of optimal designs. Therefore, this paper aims to understand the characteristics of near-optimal solutions using designs from the retrofitted OPUS/NSGA-II Pareto fronts of four distinct networks (Hanoi, Balerma, Fossolo, and Modena). Moreover, fractal characteristics of the networks’ energy dissipation, flow, and diameter distribution have been analyzed for this purpose. In this way, outcomes suggest that the hydraulic gradient line box dimension in optimal designs approaches a value of two, demonstrating that objects resemble a single-plane surface. These promising results propose fractal analysis as a practical design criterion due to its hydraulic significance and low computational cost.

Controlling the anisotropy behaviour of 3D printed ceramic cores: From intralayer particle distribution to interlayer pore evolution

The ceramic cores used in advanced aero-engine blades are becoming increasingly complex. Vat photopolymerisation 3D printing core technology has been used to compensate for the limitations of traditional hot-injection processes in the preparation of complex cores. However, 3D printed cores exhibit anisotropy of strength and sintering shrinkage, which requires further research and development. Herein, ceramic core samples were prepared from the X, Y, and Z directions using vat photopolymerisation 3D printing technology, and the anisotropic behaviour was systematically studied. The mechanism of core delamination was studied using a finite element simulation of slurry spreading during the printing process. In the slurry spreading process, the flow rate of the slurry middle layer was faster than that of the upper and lower surfaces, and fine particles concentrated more easily on the upper and lower surfaces. The interface between the layers was composed of fine particles. The interfacial sintering was compact and the pores were small. The interior of the lamellar structure was composed of coarse particle with large and dispersed pores. In addition, the distribution of pores within the 3D printed core presents an evolution law during the sintering process. With an increase in the sintering temperature, the pores move toward the interface between the layers and are enriched, and the pores coalesced to form larger pores at the interface. When sintered at high temperatures, the interfacial pores formed a gradient line between the porous layers. The combination of finite element simulation and experimentation provides theoretical guidance for the control of the layered structure and anisotropy of 3D printed cores. This promotes the application of 3D printed ceramic technology in the industrial field.

Stochastic gradient line Bayesian optimization for efficient noise-robust optimization of parameterized quantum circuits

Optimizing parameterized quantum circuits is a key routine in using near-term quantum devices. However, the existing algorithms for such optimization require an excessive number of quantum-measurement shots for estimating expectation values of observables and repeating many iterations, whose cost has been a critical obstacle for practical use. We develop an efficient alternative optimization algorithm, stochastic gradient line Bayesian optimization (SGLBO), to address this problem. SGLBO reduces the measurement-shot cost by estimating an appropriate direction of updating circuit parameters based on stochastic gradient descent (SGD) and further utilizing Bayesian optimization (BO) to estimate the optimal step size for each iteration in SGD. In addition, we formulate an adaptive measurement-shot strategy and introduce a technique of suffix averaging to reduce the effect of statistical and hardware noise. Our numerical simulation demonstrates that the SGLBO augmented with these techniques can drastically reduce the measurement-shot cost, improve the accuracy, and make the optimization noise-robust.

Sound source localization of non-synchronous measurements beamforming based on the truncated nuclear norm regularization

Due to the size and aperture limitations of the microphone array, poor resolution and limited working frequency range are challenging for acoustic imaging with beamforming methods. In this work, two fast iteration algorithms, alternating direction method of multipliers (ADMM) and accelerated proximal gradient line search method (APGL) based on truncated nuclear norm regularization (TNNR), are proposed to complete the cross-spectral matrix for non-synchronous measurements beamforming. Compared with current matrix completion algorithm based on nuclear norm minimization (NNM), TNNR is regarded as a better approximation to the rank function, which means it can approach the real solution better and restore the sound sources accurately at a low signal-to-noise ratio (SNR) environment. Among the TNNR-APGL and TNNR-ADMM, the TNNR-APGL algorithm has a lower matrix completion error and a shorter calculation time. The localization results of TNNR-ADMM method are more robust to the number of measurements. The experiment results show that TNNR methods greatly improve the resolution of conventional beamforming (CBF) and suppress the sidelobes under low SNR conditions, which indicates that the non-synchronous measurements beamforming based on TNNR methods has the potential to be applied in the industrial scene and low SNR environment.

Development of grain-scale slip activity and lattice rotation fields in Inconel 718

Using a combination of in-situ high-resolution digital image correlation (HR-DIC), Heaviside-DIC method (H-DIC), and crystal plasticity finite element (CPFE), we investigate the evolution of intragranular lattice rotations and slip activity during monotonic and cyclic loading in a high performance, polycrystalline face centered cubic material. The CPFE employs a quasi-3D model microstructure, which is a highly resolved mirror representation of the experimental in-situ test sample. In agreement, the measurements and calculations reveal that most grains, regardless of their size and lattice orientation, develop intragranular lattice rotation gradients that span the grain. For a small cluster of grains on the deformed material, we perform HR-DIC analysis of slip lines to demonstrate agreement in the active slip systems and changes in this local slip activity across the individual grains. The combined analysis reveals that deforming grains are divided into sub-granular regions of uniform lattice rotation and these regions are most often associated with only one or two active slip systems. The gradient lines that divide them correspond to changes in the predominant slip system. The model is used to examine the evolution of intragranular lattice rotation in a single fully reversed tension-compression cycle. The calculations indicate that intragranular gradients intensify during the reverse loading path as nearest neighboring regions appear to shed lattice rotation, increasing the lattice rotation in some regions, while shutting down rotation in neighboring regions. These findings provide insight into the irreversible changes that develop within deforming grains at the scale of the grain, particularly the heterogeneous development of intragranular lattice rotation in early stages of deformation, which could serve as precursors to localization.

The Design of Terahertz Frequency Quadruplers Based on Discrete Schottky Diodes.

On the basis of the W-band power source, a single-stage frequency quadrupler method was used to implement two 335 GHz frequency quadruplers. The two frequency quadruplers adopted a traditional binomial matching structure and an improved gradient line matching structure, respectively. An idle loop was added to the overall circuit in the design of the DC filter and low-pass filter. The improved gradient line matching structure reduced the circuit length while increasing the bandwidth, effectively reducing the power loss on the transmission line. A micro-strip circuit was fabricated with a 50 μm thick quartz circuit and was mounted onto a split waveguide block. The results showed that the output power of the quadrupler with the improved matching structure was better than that of the quadrupler with the conventional matching structure. The peak output power of the improved frequency quadrupler was 4.75 mW at 333 GHz when driven with 200 mW. In contrast, this improved structure broadened the bandwidth by 8 GHz and reduced the length of the substrate by 0.607 mm, effectively reducing the length of the traditionally designed circuit by 11.5%.

Impact of Cooling on Water and Salt Migration of High-Chlorine Saline Soils

Secondary salinization is a common problem in saline soil projects. In order to grasp the mechanism of water and salt migration of high-chlorine saline soil during the cooling process, the saline soils along the Qarhan-Golmud Highway in the Qinghai-Tibet Plateau were selected as test samples. Firstly, the basic physical parameter test and the soluble salt chemical experiment were carried out and obtained liquid and plastic limits, dry density, etc. Secondly, freezing temperature experiments and water-salt migration experiments under one-way cooling conditions were conducted according to the actual environmental conditions, and after the temperature gradient line of the soil sample was stable, water content and labile salt chemistry experiments were conducted to obtain the distribution of water and salt contents of soil samples. Finally, the effect of crystallization-water phase transition on water and salt migration and the effect of chloride salt on the temperature of crystallization-water phase transition were considered, and a mathematical model applicable to the water and salt migration of highly chlorinated saline soils under the effect of unidirectional cooling was established and solved with COMSOL Multiphysics software, and the correctness of the model was verified by comparing the simulation results with the experimental results. The study found that (1) during the one-way cooling process, both water and salt showed a tendency to migrate to the cold end. The MC (saline soil with medium chlorine content) with an initial water content of 16.9% and Cl− content of 3.373% was measured to reach a 17.6% water content and 3.76% Cl− content at the cold (top) end after the experiment. The HC (saline soil with high chlorine content) with an initial water content of 6.6% and Cl− content of 17.928% was measured to reach a 6.83% water content and 18.8% Cl− content after the experiment and (2) after the one-way cooling experiment of the MC, the water content at a distance of 1–2 cm from the cold end has abrupt changes, which may be caused by a small amount of crystallization—water phase transition at this location. At the same time, according to the temperature change graph during the cooling process, the phase change temperature was set to −9°C in the numerical simulation process to match the experimental results.

Life Cycle Modelling of Extraction and Processing of Battery Minerals—A Parametric Approach

Sustainable battery production with low environmental footprints requires a systematic assessment of the entire value chain, from raw material extraction and processing to battery production and recycling. In order to explore and understand the variations observed in the reported footprints of raw battery materials, it is vital to re-assess the footprints of these material value chains. Identifying the causes of these variations by combining engineering and environmental system analysis expands our knowledge of the footprints of these battery materials. This article disaggregates the value chains of six raw battery materials (aluminum, copper, graphite, lithium carbonate, manganese, and nickel) and identifies the sources of variabilities (levers) for each process along each value chain. We developed a parametric attributional process-based life cycle model to explore the effect of these levers on the greenhouse gas (GHG) emissions of the value chains, expressed in kg of CO2e. The parametric life cycle inventory model is used to conduct distinct life cycle assessments (LCA) for each material value chain by varying the identified levers within defined engineering ranges. 570 distinct LCAs are conducted for the aluminum value chain, 450 for copper, 170 for graphite, 39 for lithium carbonate via spodumene, 20 for lithium carbonate via brine, 260 for manganese, and 440 for nickel. Three-dimensional representations of these results for each value chain in kg of CO2e are presented as contour plots with gradient lines illustrating the intensity of lever combinations on the GHG emissions. The results of this study convey multidimensional insights into how changes in the lever settings of value chains yield variations in the overall GHG emissions of the raw materials. Parameterization of these value chains forms a flexible and high-resolution backbone, leading towards a more reliable life cycle assessment of lithium-ion batteries (LIB).

Localization of incoherently distributed near-field sources: A low-rank matrix recovery approach

This paper considers the localization problem of incoherently distributed near-field (IDNF) sources. It is observed that the angular and range spreads of IDNF source signals produce a useful low-rank structure, which can be used to estimate the joint angular-range distribution (JARD) for IDNF sources. Then, by analyzing the low-rank property of the JARD matrix, a rank minimization problem is formulated to directly estimate the JARD matrix, which can be solved efficiently by the truncated nuclear norm regularization with accelerated proximal gradient line search method (TNNR-APGL). Finally, for performance comparisons, off-grid estimators are applied to estimate the key parameters of the JARD. Compared with conventional algorithms, the proposed method enjoys better parameter estimation performance and faster computation, requiring no parameterized distribution model and multi-dimensional search. Numerical experiments are included to demonstrate the performance of the proposed solution.

Simultaneous drainage events from supraglacial lakes on the southern Inylchek Glacier, Central Asia

AbstractTo understand the mechanism of simultaneous drainage event related to supraglacial lakes on a debris-covered glacier, we investigated water-level variations of supraglacial lakes on the southern Inylchek Glacier in Kyrgyzstan. To examine these variations, we used daily aerial images for 2017–2019 from an uncrewed aerial vehicle that were converted to 15 cm-digital surface models and ortho-images. Our main results are as follows: (1) When one lake drained, the water levels of other lakes simultaneously increased, indicating that drainage water is shared with several lakes through a main englacial conduit. In one drainage event, a branched off englacial conduit clearly connected to a main englacial conduit. (2) Sometimes several lakes discharged simultaneously, indicating that several lakes had connected to a main englacial conduit that had opened. Such cases can cause larger-scale drainage than that from the opening of a branched off englacial conduit. (3) Simultaneous drainage occurred twice in the same year, each time through a different conduit, indicating that the main englacial conduit can be abandoned and reused. (4) In some lakes, the water level on the hydraulic gradient line increased gradually with nearly the same increase rate just before drainage. Such an increase may be an indicator of a possible simultaneous drainage event.