Coexistence System Research Articles

Performance, comparison and utilization of reduced sulfur (−2) compounds (S2−, FeS and SCN−) in autotrophic denitrification process by thiosulfate-driven autotrophic denitrifier

The coexistence of reduced sulfur (−2) compounds (S2−, FeS and SCN−) are found in some industrial wastewaters due to pre-treatment of Fe(II) salts. These compounds as electron donors have attracted increasing interest in autotrophic denitrification process. However, the difference of their functions still remain unknown, which limit efficient utilization in autotrophic denitrification process. The study aimed to investigate and compare utilization behavior of these reduced sulfur (−2) compounds in autotrophic denitrification process activated by thiosulfate-driven autotrophic denitrifiers (TAD). Results showed that the best denitrification performance was observed in SCN−; while the reduction of nitrate was significantly inhibited in S2− system and the efficient accumulation of nitrite was observed in FeS system with cycle experiments continuing. Additionally, intermediates containing sulfur were produced rarely in SCN− system. However, the utilization of SCN− was limited obviously in comparison with S2− in coexistence systems. Moreover, the presence of S2− increased the accumulation peak of nitrite in coexistence systems. The biological results indicated that the TAD utilized rapidly these sulfur (−2) compounds, in which genus of Thiobacillus, Magnetospirillum and Azoarcus might play main roles. Moreover, Cupriavidus might also participate in sulfur oxidation in SCN− system. In conclusion, these might be attributed to the characteristics of sulfur (−2) compounds including the toxicity, solubility and reaction process. These findings provide theoretical basis for regulation and utilization of these reduced sulfur (−2) compounds in autotrophic denitrification process.

Field measures of strengthen plant-microbial remediation of PAHs-FQs compound pollution.

In this study, five PAHs (benzo [b] fluoranthene (BbF), phenanthrene (Phe), fluoranthene (Flu), fluorene (Fl), benzo [A] pyrene (Bap)), and five FQs (ofloxacin (OFL), enrofloxacin (ENR), ciprofloxacin (CIP), norfloxacin (NOR), lomefloxacin (LOM)) were selected as ligands; peroxidase (1NML) was selected as receptor degrading protein. In the plant-microbial degradation, the factors with significant inhibitory effects are NOR, Bap, CIP, ENR, OFL, Flu, LOM, Phe, Fl, and BbF by the fractional factorial design experiment and molecular docking-assisted molecular dynamics methods. Using Taguchi experiment and molecular dynamics simulation methods, the main external field measures were designed and screened to effectively promote the degradation of PAHs-FQs under the combined pollution scenarios of Bap-CIP and BbF-NOR, respectively. The peroxidase mutation design plans with enhanced substrate affinity were then designed and screened using the DS software by predicting the virtual key amino acid of peroxidase. The novel biodegradable enzymes 2YCD-1, 2YCD-4, 2YCD-5, 2YCD-7, and 2YCD-9 had better structures and showed excellent degradability for PAHs and FQs. This study explored the degradation rules of the composite pollutants in the coexistence systems of multiple PAHs and FQs, providing the best external field measures for the control and treatment of the combined pollution effects of different PAHs and FQs. Overall, the current study has important practical significance for promoting the plant-microbial joint remediation of PAHs-FQs pollution and for reducing the combined pollution of PAHs and FQs in farmland systems.

Enhancement for Spectrum Compatibility by Mutual Interference Management

This paper investigates the spectral compatibility for a communication system operating on same frequency with radar by exploiting multiple input multiple output (MIMO) configurations, where the radar system acts as the primary platform, while the communication system is the secondary platform. A multiple constrained formulation including transmitter power and peak-to-average power ratio (PAR), aims at radar signal-to-interference-plus-noise ratio (SINR) and communication power harvesting optimization. The design variables consist of the space-time transmit sequences for the two coexistence systems. We derive an optimal procedure that decomposes the developed non-convex formulation into a sequence of subproblems based on the cost function modified alternating direction method of multipliers (CM-ADMM) techniques. Finally, to reveal the effectiveness and superiority of the proposed algorithm in different scenarios, numerical results are provided.

Simultaneous removal of Cd(II) and As(V) by ferrihydrite-biochar composite: Enhanced effects of As(V) on Cd(II) adsorption

The coexistence of cadmium (Cd(II)) and arsenate (As(V)) pollution has long been an environmental problem. Biochar, a porous carbonaceous material with tunable functionality, has been used for the remediation of contaminated soils. However, it is still challenging for the dynamic quantification and mechanistic understanding of the simultaneous sequestration of multi-metals in biochar-engineered environment, especially in the presence of anions. In this study, ferrihydrite was coprecipitated with biochar to investigate how ferrihydrite-biochar composite affects the fate of heavy metals, especially in the coexistence of Cd(II) and As(V). In the solution system containing both Cd(II) and As(V), the maximum adsorption capacities of ferrihydrite-biochar composite for Cd(II) and As(V) reached 82.03 µmol/g and 531.53 µmol/g, respectively, much higher than those of the pure biochar (26.90 µmol/g for Cd(II), and 40.24 µmol/g for As(V)) and ferrihydrite (42.26 µmol/g for Cd(II), and 248.25 µmol/g for As(V)). Cd(II) adsorption increased in the presence of As(V), possibly due to the changes in composite surface charge in the presence of As(V), and the increased dispersion of ferrihydrite by biochar. Further microscopic and mechanistic results showed that Cd(II) complexed with both biochar and ferrihydrite, while As(V) was mainly complexed by ferrihydrite in the Cd(II) and As(V) coexistence system. Ferrihydrite posed vital importance for the co-adsorption of Cd(II) and As(V). The different distribution patterns revealed by this study help to a deeper understanding of the behaviors of cations and anions in the natural environment.

Co-deposition characteristics of hydrates and sands in gas-salty water-sands flow system

The study of hydrate flow assurance is critical for the efficient and safe development of natural gas hydrates. The natural gas produced by the dissociation of hydrate may re-hydrate in the gathering pipeline, and even lead to the blockage of the gathering pipeline. However, the co-deposition mechanism of the Micron-sized Sand Particles(MSPs) produced in the exploitation, and natural gas hydrate particles during pipeline transportation is still unclear. Therefore, the hydrates and MSPs slurry flow law and co-deposition mechanism are studied by horizontal high-pressure flow loop experiments. A new method to calculate the thickness of the deposition layer for water-dominant systems is proposed. Then, based on the variation of deposition layer thickness, the solid deposition process and flow behaviors are discussed in the pure water system, the salt-containing system, the sand-containing system, and the salt-sand coexistence system, respectively. The results show that the hydrate-MSPs co-deposition process is divided into five stages in the salt-sand coexistence system: the initial deposition stage, hydrate formation and adhesion on the pipe wall stage, rapid deposition stage, deposition layer sloughing stage, and stable deposition stage. And the hydrate-MSPs co-deposits in various stages are characterized by the Hydrate Aggregates Deposition Rate, the Hydrate Aggregates Deposition Layer Thickness, and the particle Chord Length Distribution. The influence of sand particle concentration and initial flow velocity on the hydrate-MSPs co-deposition process in the salt-sand coexistence system is also explored. In addition, the interaction between particles in the deposition process is revealed by Particle Vision and Measurement. The findings of this work provide insights into the solid deposition process in the salt-sand coexistence system, which is beneficial for flow assurance in natural gas hydrate production.

Data-Driven Spectrum Partition for Multiplexing URLLC and eMBB

Multiplexing ultra-reliable low-latency communications (URLLC) and enhanced mobile broadband (eMBB) are critical in the next generation mobile network. URLLC requires ultra-high reliability and extremely low latency, whereas eMBB demands high data rates. Thus, the coexistence system of URLLC and eMBB faces the challenge of sharing the spectrum efficiently and effectively. In this study, we comprehensively investigate the state of the art spectrum partition methods in combined URLLC and eMBB services. We formulate a joint optimization problem for maximizing the eMBB throughput and guaranteeing the URLLC performance. For the eMBB and URLLC multiplexing system, a full separative spectrum partition scheme based on data-driven genetic algorithm-based spectrum partition (DDGSP) is proposed. Our simulation results demonstrate that the proposed DDGSP can make the URLLC and eMBB coexistence system outperform the state-of-the-art methods in terms of the error rate and computational efficiency.

Joint Secure Transmit Beamforming Designs for Integrated Sensing and Communication Systems

Integrated sensing and communication (ISAC), which allows individual radar and communication systems to share the same spectrum bands, is an emerging and promising technique for alleviating spectrum congestion problems. In this paper, we investigate how to exploit the inherent interference from strong radar signals to ensure the physical layer security (PLS) for the considered multi-user multi-input single-output (MU-MISO) communication and colocated multi-input multi-output (MIMO) radar coexistence system. In particular, with known eavesdroppers' channel state information (CSI), we propose to jointly design the transmit beamformers of communication and radar systems to minimize the maximum eavesdropping signal-to-interference-plus-noise ratio (SINR) on multiple legitimate users, while guaranteeing the communication quality-of-service (QoS) of legitimate transmissions, the requirement of radar detection performance, and the transmit power constraints of both radar and communication systems. When eavesdroppers' CSI is unavailable, we develop a joint artificial noise (AN)-aided transmit beamforming design scheme, which utilizes residual available power to generate AN for disrupting malicious receptions as well as satisfying the requirements of both legitimate transmissions and radar target detection. Extensive simulations verify the advantages of the proposed joint beamforming designs for ISAC systems on secure transmissions and the effectiveness of the developed algorithms.

SENS+: A Co-Existing Fabrication System for a Smart DFA Environment Based on Energy Fusion Information.

In factories, energy conservation is a crucial issue. The co-fabrication space is a modern-day equivalent of a new factory type, and it makes use of Internet of Things (IoT) devices, such as sensors, software, and online connectivity, to keep track of various building features, analyze data, and produce reports on usage patterns and trends that can be used to improve building operations and the environment. The co-fabrication user requires dynamic and flexible space, which is different from the conventional user's usage. Because the user composition in a co-fabrication space is dynamic and unstable, we cannot use the conventional approach to assess their usage and rentals. Prototyping necessitates a specifically designed energy-saving strategy. The research uses a "seeing-moving-seeing" design thinking framework, which enables designers to more easily convey their ideas to others through direct observation of the outcomes of their intuitive designs and the representation of their works through design media. The three components of human behavior, physical manufacture, and digital interaction are primarily the focus of this work. The computing system that connects the physical machine is created through communication between the designer and the digital interface, giving the designer control over the physical machine. It is an interactive fabrication process formed by behavior. The Sensible Energy System+ is an interactive fabrication process of virtual and real coexistence created by combining the already-existing technology, the prototype fabrication machine, and SENS. This process analyzes each step of the fabrication process and energy, fits it into the computing system mode to control the prototype fabrication machine, and reduces the problem between virtual and physical fabrication and energy consumption.

Performance Modeling of an NR-U and WiFi Coexistence System With NR-U Type B Multichannel Access Procedure

New radio-based access to unlicensed bands (NR-U) multichannel access procedures are 3GPP standards for supporting 5G NR-U and WiFi coexistence in unlicensed frequency bands. NR-U provides a new solution to alleviating the severe spectrum scarcity problem of 5G cellular networks in licensed frequency bands for supporting diverse Internet of Things (IoT) services. This article studies the performance modeling of an NR-U and WiFi coexistence system using the NR-U Type B multichannel access procedure and the WiFi DCF procedure and focuses on a system model with two unlicensed channels: 1) a primary channel and 2) a secondary channel. 2-D Markov models are first built to describe the NR-U category-4 LBT procedure and the WiFi DCF procedure on the primary channel, respectively. A 3-D Markov model is then built to describe the WiFi DCF procedure on the secondary channel, taking into account the effect of the NR-U Type B multichannel access procedure. Based on the built Markov models, performance models are further derived for analyzing the system performances in terms of system throughput and packet delay on the primary channel and/or secondary channel. The derived performance models are validated through simulation results. The impacts of the number of NR-U gNBs/WiFi APs and major system parameters on the system performances are investigated based on the derived performance models.

Influence of Humic Acids on the Removal of Arsenic and Antimony by Potassium Ferrate

Although the removal ability of potassium ferrate (K2FeO4) on aqueous heavy metals has been confirmed by many researchers, little information focuses on the difference between the individual and simultaneous treatment of elements from the same family of the periodic table. In this project, two heavy metals, arsenic (As) and antimony (Sb) were chosen as the target pollutants to investigate the removal ability of K2FeO4 and the influence of humic acid (HA) in simulated water and spiked lake water samples. The results showed that the removal efficiencies of both pollutants gradually increased along the Fe/As or Sb mass ratios. The maximum removal rate of As(III) reached 99.5% at a pH of 5.6 and a Fe/As mass ratio of 4.6 when the initial As(III) concentration was 0.5 mg/L; while the maximum was 99.61% for Sb(III) at a pH of 4.5 and Fe/Sb of 22.6 when the initial Sb(III) concentration was 0.5 mg/L. It was found that HA inhibited the removal of individual As or Sb slightly and the removal efficiency of Sb was significantly higher than that of As with or without the addition of K2FeO4. For the co-existence system of As and Sb, the removal of As was improved sharply after the addition of K2FeO4, higher than Sb; while the latter was slightly better than that of As without K2FeO4, probably due to the stronger complexing ability of HA and Sb. X-ray energy dispersive spectroscopy (EDS), X-ray diffractometer (XRD), and X-ray photoelectron spectroscopy (XPS) were used to characterize the precipitated products to reveal the potential removal mechanisms based on the experimental results.

A Study on the Corrosion Behaviour and Mechanism of Associated Gas on Surface Pipes in Fire-flooding Oil Recovery

The fire-flooding associated gas in Liaohe Oilfield contains a mixture of gases, of which O2 and CO2 will interact with each other and corrode surface pipes. In this paper, the corrosion rate of different pipe materials in descending order is 20# steel>20G steel> L360 steel>L245 steel by weight loss method, painting, and chrome plating can reduce the corrosion rate. In combination with SEM, EDS, XRD and other means to analyze the corrosion mechanism of the CO2-O2 coexistence system, a loose and porous Fe(OH)3 film is formed on the surface of the material. After removing the corrosion products, needle-shaped pores with different diameters appear, indicating serious pitting corrosion. The corrosion products are composed of Fe and O elements, mainly the dehydrated products FeOOH and Fe2O3.

Joint Rate Allocation and Power Control for RSMA-Based Communication and Radar Coexistence Systems

We consider a rate-splitting multiple access (RSMA)-based communication and radar coexistence (CRC) system. The proposed system allows an RSMA-based communication system to share spectrum with multiple radars, which significantly improves spectral efficiency, energy efficiency and quality of service (QoS) of communication users (CUs). Due to the spectrum sharing, the communication network and the radars cause interference to each other, which reduces the signal-to-interference-plus-noise ratio (SINR) of the radars as well as the data rate of the CUs. Therefore, a major problem is to maximize the sum rate of the CUs while guaranteeing their QoS requirements of data transmissions and the SINR requirements of multiple radars. To achieve the objective, we formulate a new problem that optimizes i) common rates of the CUs, ii) transmit power of the common message of the CUs, iii) transmit power of the private messages for the intended CUs, and iv) transmit power of the radar systems. The problem is non-convex, and thus we propose two algorithms. The first sequential quadratic programming (SQP) as the state-of-the-art in nonlinear programming method can quickly return a local optimal solution. The second is an additive approximation scheme (AAS) which solves the problem globally in a reasonable amount of time. Simulation results show the significant improvement of the AAS compared with the SQP in terms of sum rate. Furthermore, with the AAS, the sum rate of the CUs only slightly decreases when the radars' SINR is significantly increased. This implies that the AAS supports the RSMA-based communication system which allows to well coexist with the radars.

Polymer-Dispersed Liquid Crystal Films on Flexible Substrates with Excellent Bending Resistance and Spacing Stability

Polymer-dispersed liquid crystals (PDLCs) are very attractive due to their electrically switchable properties. However, current PDLC films still have problems such as high driving voltages, low contrast ratio (CR), and poor bending resistance and spacing stability. To solve these problems, a PDLC film with a system of coexisting polymer spacer columns and polymer network was proposed. First, based on the adhesive systems of IBMA and UV6301, the effects of IBMA concentration and LC content on the morphology of the polymer network and the electro-optical properties of PDLC were investigated, respectively. Then, the effects of the process conditions of mask polymerization such as temperature, time, and UV light intensity on the morphology and electro-optical properties of the polymer spacer columns were systematically investigated. It was found that PDLC films with the coexistence system exhibit both excellent electro-optical properties and outstanding bending resistance and spacing stability. Thus, it provides new practical possibilities for the preparation of high-performance PDLC films used in flexible devices.

Preparation of Flexible Liquid Crystal Films with Broadband Reflection Based on PD&SLC.

A simple and efficient method for the preparation of a film with flexible characteristic and selective reflection of near-infrared light is proposed. Based on the coexistence system (PD&SLC) of polymer dispersed liquid crystals (PDLC) and polymer stabilized liquid crystals (PSLC), it combines the flexibility of PDLC with the selectively reflection of PSLC. Innovative use of step-by-step light curing to achieve microstructural differences in the three-dimensional orientation of the material is proposed. That is, the difference between PDLC and PSLC in the planar orientation, as well as the gradient distribution of cholesteric phase liquid crystal pitch in the cell thickness direction, is observed. While realizing the flexibility of the material, the function of broadening the reflection bandwidth is fulfilled. This method of preparing liquid crystal films is expected to have great potential for applications, such as flexible smart windows, infrared light shielding, and sensors.

Effect of Different Blades on Suspension Characteristics of Anaerobic Digestion Particles and Energy Consumption Optimization Analysis

In this study, a solid-liquid mixing system model was established to simulate the coexistence of floating particles (FP) and sinking particles (SP) in the early stage of anaerobic digestion, and the mixing effect and energy consumption of the system were investigated. Four typical blades were selected to compare the solid phase distribution of straw particles under different blade stirring, and the distribution of FP and SP in the coexistence system was clarified. Then the combination of full-factorial design and numerical simulation was applied to compare the effect of blade diameter and blade width on particle mixing, which was better than that of immersion depth. A comprehensive equation was further established to balance the weight between the particle mixing effect and energy consumption and improve the blade design. It provided theoretical support for the design and amplification of subsequent stirring equipment.

Ising Machine Based on Bistable Microelectromechanical Systems

We propose an Ising machine made of microelectromechanical systems (MEMS), where the annealing process is automatically executed by a dissipation mechanism. The core structure is a series of buckled plates. Two stable positions of each plate (left and right) represent its binary state acting as a bit so that a plate works as a mechanical memory. The electrostatic interaction between adjacent plates is introduced by applying voltage. Plates continue to flip between two stable buckled positions until the series of plates reaches a local minimum due to the damping of the mechanical motion. \red{First, we design Ising machines simulating a ferromagnetic (FM) interaction and an antiferromagnetic (AF) interaction separately. Then, we propose a fully-connected MEMS\ network representing a coexistence system of FM and AF interactions in an arbitrary way, by way of which an arbitrary combinatorial problem described by the Ising model can be solved.} The present mechanism works at room temperature without external magnetic field, which is very different from the standard classical or quantum annealing mechanism.

Beamforming and Waveform Designing for Spectrum Coexistence System Based on Constructive Interference

In this letter, a joint communication beamforming and radar transmit waveform design method is proposed for radar and communication coexistence (RCC) systems. The optimization problem is designed to maximize the radar signal-to-interference-plus-noise ratio (SINR), under the constraints of communication constructive interference (CI), radar waveform similarity and constant modulus. A novel block fading (BF) algorithm is developed for tackling the non-convexity of the problem constructed, where the closed-form sub-optimal solutions are obtained by transforming the original problem into an element-by-element phase angle problem. Finally, the numerical simulation results verify the superiority of the proposed algorithm on the performance of radar detection and multi-user interference (MUI) elimination.

Intelligence Reflecting Surface-Aided Integrated Data and Energy Networking Coexisting D2D Communications

In this paper, we consider an integrated data and energy network and D2D communication coexistence (DED2D) system. The DED2D system allows a base station (BS) to transfer data to information-demanded users (IUs) and energy to energy-demanded users (EUs), i.e., using a time-fraction-based information and energy transfer (TFIET) scheme. Furthermore, the DED2D system enables D2D communications to share spectrum with the BS. Therefore, the DED2D system addresses the growth of energy and spectrum demands of the next generation networks. However, the interference caused by the D2D communications and propagation loss of wireless links can significantly degrade the data throughput of IUs. To deal with the issues, we propose to deploy an intelligent reflecting surface (IRS) in the DED2D system. Then, we formulate an optimization problem that aims to optimize the information beamformer for the IUs, energy beamformer for EUs, time fractions of the TFIET, transmit power of D2D transmitters, and reflection coefficients of the IRS to maximize IUs’ worse throughput while satisfying the harvested energy requirement of EUs and D2D rate threshold. The max-min throughput optimization problem is computationally intractable, and we develop an alternating descent algorithm to resolve it with low computational complexity. The simulation results demonstrate the effectiveness of the proposed algorithm.

On the calculation of crystal–melt interface free energy and interface stiffness using Ni as a model system

Both interface free energy and interface stiffness are crucial parameters in governing the interface morphologies of crystal–melt coexistence systems from which different methods were reported separately to determine these parameters in turn. However, the correlation among these methods has not been a concern in previous research studies. In this work, we created two Ni models of crystal–melt coexistence systems based on a basic crystal–melt interface kinetic equation. Then, the interface stiffness, interface free energy, and anisotropy parameters were calculated using three methods, which are the capillary fluctuation method, critical nucleus method, and modified critical nucleus method. The results are in good agreement with each other. Meanwhile, the interface free energies calculated in our work agree well with the values from experiments and existing simulations.

Priority setting for 2050 future images and policy agendas of the Republic of Korea: engaging the national assembly

PurposeThis study aims to identify and prioritize preferable 2050 future images and the policy agendas of the Republic of Korea using a bottom-up approach, involving legislative staff of the National Assembly as well as experts from various fields.Design/methodology/approachThe authors derived three future images from the future policy agendas selected by experts: society for growth of smart generations (GS), society for sustainability and safety (SS) and society for coexistence and diversity (CD). The survey conducted among legislative staff (n = 189) shows that the most preferred future image was SS. Then, the authors prioritized the policy agendas that aligned with future images using priority calculating methods.FindingsThe most prioritized policy agenda was “Social system for coexistence to resolve social conflict,” followed by “Social sustainability through tackling low birth rate.” The next was “Social integration policies to embrace diverse family composition” and “Responding to social change and knowledge transformation caused by artificial intelligence.” Among the top five rankings, two agendas from each SS and CD were selected.Practical implicationsTo achieve the preferred future images, implementing policies related to sustainability, human rights and coexistence are necessary for continuous collaboration among stakeholders, especially those from the legislature.Originality/valueThis study presents a method of involving the National Assembly, which is a representative institution of the people and composed of various political parties, to set the national’s future vision and agenda from a long-term perspective.