Exchange Channels Research Articles

Highly efficient removal of strontium from contaminated wastewater by a porous zirconium phosphate material

Effective and efficient disposal of radioactive pollution has been crucial for responding to unexpected nuclear accidents and guaranteeing the sustainable development of nuclear energy. In this study, a kind of porous zirconium phosphate was synthesized with a sol–gel process followed by a post-synthesis modification to remove the radioactive Sr2+ from wastewater. The prepared materials were characterized by different technologies including FT-IR, SEM-EDS, XRD and XPS, and then the adsorption performance was evaluated in batch and column modes. Experimental results suggested that the porous zirconium phosphate adsorbent was successfully prepared with Na+ dispersed in the channels for exchange. It inherited the excellent properties of zirconium dioxide aerogel and exhibited mesoporous structure and large specific surface area. Compared with traditional zirconium phosphate, the adsorption kinetics and the adsorption capacity were improved simultaneously. Especially, it showed excellent selectivity towards Sr2+ among different cations, and even could remove the low-level Sr2+ from natural seawater efficiently, which powerfully demonstrated that the prepared material could be applied in the treatment of practical wastewater. Spectra studies uncovered that the adsorption activities were dominated by the ion exchange mechanism between external Sr2+ and interlaminar Na+ or H+. In conclusion, this paper not only reports a novel synthesis strategy for the acquisition of porous zirconium phosphate, but also presents a promising adsorbent for the Sr2+ removal.

"A Light Bulb in Every House": The Istanbul General Electric Factory and American Technology Transfer to Turkey.

In 1946, Turkish entrepreneur Vehbi Koç signed an agreement with the U.S. firm General Electric to build and operate its first light bulb factory in the Near/Middle East, in Istanbul. This private joint venture introduced new manufacturing techniques, business practices, and consumer habits to Turkey, opening channels of postwar technological exchange. Closer examination of the GE-Koç partnership reveals that during the early Cold War, the transfer and embedding of American technologies in Turkey was a politically complicated process of innovation that required constant adaptation. Fraught with unforeseeable obstacles, it also required cautious negotiation with multiple transnational actors. The story of the GE-Koç partnership thus adds a new dimension to historical understandings of the Turkish Cold War experience and the Americanization of the region. It illustrates how transferring a nonmilitary, soft-power, domestic technology-the light bulb-played a significant role in Turkish-American relations and therefore contributes to studies of U.S. Cold War diplomacy through transnational investment in innovation.

Reactive and Nonreactive Collisions between NO(X2Π) and O(3P) under Hyperthermal Conditions.

Quasiclassical trajectory calculations are performed for hyperthermal collisions between NO(X2Π) and O(3P) on recently developed potential energy surfaces for the lowest doublet and quartet states of the NO2 system. Three product channels are investigated, and their branching fractions are in reasonably good agreement with the recent crossed molecular beam study at 84 kcal/mol of collision energy. The dominant inelastic channel has a strong forward scattering bias and a high translational energy distribution with limited internal excitation in the scattered NO. The exchange channel has significantly higher NO internal excitation and is also forward biased. The abstraction channel producing internally excited O2 has the smallest branching fraction and a broader angular distribution also with a forward peak. The angular and translational energy distributions in the three channels are consistent with experiment, but the agreement is not always quantitative. The sources of the differences are discussed. Finally, the impact of NO vibrational excitation on the reactive channels and the corresponding rate coefficients are reported.

Mo-induced in-situ architecture of NixCoyP/Co2P heterostructure nano-networks on nickel foam as bifunctional electrocatalysts for overall water splitting

Transition metal phosphides (TMPs) exhibit excellent competitiveness for electrochemical splitting water due to their high electrical conductivity and remarkable physicochemical stability. However, pure single-phase TMPs still possess some disadvantages, such as the limited number of active sites and difficulty in greatly accelerating mass/charge transfer. Elemental doping is a practical way to manipulate the intrinsic electronic structures of TMPs and optimize the adsorption and desorption process of intermediates during the water splitting reaction. Rational construction of heterostructure electrocatalysts with high catalytic activity and excellent durability shows great potential for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Herein, we developed a nickel foam (NF)-supported NixCoyP/Co2P heterostructure anchoring on N-doped carbon (NixCoyP/Co2P@NF) via the phosphating of the organic frameworks (ZIF-67) with Mo species added. The as-synthesized NixCoyP/Co2P@NF catalyst shows a unique three-dimensional (3D) nano-network morphology with a large specific surface area and abundant channels for mass exchange. Mo doping alters the valence electronic states of the constituent elements in the initial phase (NixCoyP), thus optimizing the proton transfer from P sites to metal sites, while Co species in the secondary phase (Co2P) is conducive to the water decomposition. Moreover, the heterogeneous interface between initial and secondary phases accelerates electron conduction and further enhances the electrocatalytic efficiency. The NixCoyP/Co2P@NF catalyst shows overpotentials of 170 mV for HER and 352 mV for OER at a current density of 100 mA cm−2 in 1.0 M KOH. The current density can reach 100 mA cm−2 by applying a voltage of 1.75 V for overall water splitting in an alkaline water electrolyzer with NixCoyP/Co2P@NF acting as the anodic and cathodic electrodes. This work has achieved a heterostructure catalyst via the heteroatom-dopant induced phase transition and offered an interfacial engineering strategy for further improving the activity of bifunctional TMP catalysts.

Microscopic origin of room-temperature ferromagnetism in the double perovskite Sr2FeReO6

The puzzling observation of room temperature ferromagnetism in double perovskites $({A}_{2}{\phantom{\rule{4pt}{0ex}}BB}^{\ensuremath{'}}{O}_{6})$, despite having the magnetic lattice of B ions diluted by nonmagnetic ${B}^{\ensuremath{'}}$ ions, have been examined for ${\mathrm{Sr}}_{2}{\mathrm{FeReO}}_{6}$. Ab initio spin spiral electronic structure calculations along various high symmetry directions in reciprocal space are used to determine the exchange interactions entering an extended Heisenberg model, which is then solved classically using Monte Carlo simulations to determine the ferromagnetic transition temperature ${\phantom{\rule{4pt}{0ex}}T}_{c}$. We find that one must consider on-site Coulomb interactions at the nonmagnetic Re sites $(U)$ in order to obtain a ${T}_{c}$ close to the experimental value. Analysis of the ab initio electronic structure as well as an appropriate model Hamiltonian trace the origin of enhancement in ${T}_{c}$ with $U$ to the enhanced exchange splitting that is introduced at these sites. This in turn destabilizes the antiferromagnetic exchange channels, thereby enhancing the ${T}_{c}$. The role of occupancy at the nonmagnetic sites is examined by contrasting with the case of ${\mathrm{Sr}}_{2}{\mathrm{FeMoO}}_{6}$.

Paths toward advanced service-oriented business models: A configurational analysis of small- and medium-sized incumbent manufacturers

The present article contributes to the theory of Business Model Innovation by incumbent firms via digital servitization. Our research explores the conditions affecting manufacturers' ability to innovate their business models by developing and supplying advanced, digitally-based services. The authors performed a Qualitative Comparative Analysis via a qualitative investigation of the novel business models adopted by 19 Italian small- and medium-sized incumbent manufacturers. Our study found a series of theoretically relevant causal factors for the targeted outcome variable: size and investments, customer intimacy, and external service suppliers are crucial paths for developing successful digitally-based advanced services. The findings suggest three managerial implications: first, managers must capitalise on corporate knowledge and assets, mapping and leveraging useful people and technologies. Second, they should seek external service providers related to technology and strategy/organisation to help them update the value proposition. Third, they must build and foster customer intimacy and capitalise on key customers, either leveraging the extant sales/field service structures or envisioning new direct data exchange channels.

Exchange interactions in d5 Kitaev materials: From Na2IrO3 to α−RuCl3

We present an analytical study of the exchange interactions between pseudospin one-half ${d}^{5}$ ions in honeycomb lattices with edge-shared octahedra. Various exchange channels involving Hubbard $U$, charge-transfer excitations, and cyclic exchange are considered. Hoppings within ${t}_{2g}$ orbitals as well as between ${t}_{2g}$ and ${e}_{g}$ orbitals are included. Special attention is paid to the trigonal crystal field $\mathrm{\ensuremath{\Delta}}$ effects on the exchange parameters. The obtained exchange Hamiltonian is dominated by ferromagnetic Kitaev interaction $K$ within a wide range of $\mathrm{\ensuremath{\Delta}}$. It is found that a parameter region close to the charge-transfer insulator regime and with a small $\mathrm{\ensuremath{\Delta}}$ is most promising to realize the Kitaev spin liquid phase. Two representative honeycomb materials ${\mathrm{Na}}_{2}{\mathrm{IrO}}_{3}$ and $\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{RuCl}}_{3}$ are discussed based on our theory. We have found that both materials share dominant ferromagnetic $K$ and positive nondiagonal $\mathrm{\ensuremath{\Gamma}}$ values. However, their Heisenberg $J$ terms have opposite signs: AFM $J>0$ in ${\mathrm{Na}}_{2}{\mathrm{IrO}}_{3}$ and FM $J<0$ in $\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{RuCl}}_{3}$. This brings different magnetic fluctuations and results in their different magnetization behaviors and spin excitation spectra. Proximity to FM state due to the large FM $J$ is emphasized in $\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{RuCl}}_{3}$. The differences between the exchange couplings of these two materials originate from the opposite $\mathrm{\ensuremath{\Delta}}$ values, indicating that the crystal field can serve as an efficient control parameter to tune the magnetic properties of ${d}^{5}$ spin-orbit Mott insulators.

A Data-Driven Platform for the Coordination of Independent Visual Analytics Tools

Visual analysis of unknown data requires the combined use of various functions that are often part of standalone visual analytics (VA) tools. Performing cross-tool visual analysis with standalone VA tools, however, is a challenging and cumbersome endeavor. Some dedicated frameworks address this issue, yet in order to utilize any of them, a visual analytics tool needs to support their required API or architecture. Contrary to most existing frameworks, we present an approach that does not rely on a single predefined interchange mechanism for the entire ensemble of VA tools. Instead, we propose using any available channel for data exchange between two consecutive VA tools. This allows mixing and matching of different data exchange strategies over the course of a cross-tool analysis. In this paper, we identify the challenges associated with establishing such tool chaining platform for data-driven coordination. We further describe the structure and capabilities of data exchange and explain various functionalities of our platform in detail. Based on a demonstrating example, we discuss the limitations of our approach and elaborate new insight for the coordination of the visual output of multiple VA tools.

Digital image analysis of gas-liquid flow in a cross-corrugated plate heat exchanger channel: A feature-based approach on various two-phase flow patterns

High-resolution photographs of the air-water flow in a transparent cross-corrugated channel are analyzed using digital image processing. Gas-liquid distribution is controlled via several inlet nozzles. Flow direction is varied between upward, downward, and horizontal flow.The image analysis algorithm is applied to a wide range of void fractions and flow patterns including bubbly, intermediate and film flow. Large bubble clusters are separated using edge detection. Local film and bubbly flow are identified with texture analysis. The method is suitable for locally inhomogeneous two-phase flow which is difficult to analyze visually.Objective and reproducible results are obtained by measuring features in the processed images: Mean and maximum bubble diameter, and the ratio of local film flow are determined. For non-uniform gas injection, expansion of two-phase flow across channel width is measured. Impact of flow direction and maldistribution on two-phase flow is demonstrated by calculating differences of the features. Uncertainties of image processing results are quantified. Bias is discussed based on visual analysis of the photographs in a previous study.Models for maximum bubble diameter and local film flow ratio, used to model flow pattern transitions in a previous study, are verified: For uniform two-phase distribution, models generally agree with measured values.

Amphiphilic and Zwitterionic Multi Arylpyrroles with Near‐Infrared Aggregation‐Induced Emission for Cell Membrane Imaging

AbstractThe cell membrane protects the cell stability and balance and participates in various physiological activities as an exchange channel. Therefore, the real‐time monitoring of cell membrane biological dynamics can help us understand the physiological state of the current cell. Herein, a type of amphiphilic near infrared (NIR) aggregation‐induced emission (AIE) molecules was designed and synthesized. Multiarylpyrroles (MAPs) with a dodecyl chain at the 1‐position of the pyrrole ring, charged pyridinium sulfonate at the 2,5‐position of the pyrrole ring and free rotating aryls at the 3‐position of the pyrrole ring can target cell membranes. One of the MAPs,MAP22, had a maximum emission wavelength in the aggregation state of up to 721 nm with a large Stokes shift (∼280 nm). In addition,MAP22nanoparticles can produce reactive oxygen species (ROS) with a quantum yield of 224%. Therefore, these AIE MAPs are promising candidates for theranostic nanoagents, including NIR fluorescence imaging to target cell membranes and ablate cancer cells by producing ROS.

Measuring circular reuse magnitude and replacement rate: A new method

This study proposes a novel methodology to calculate reuse and apply this to Flanders. We combine available data from the Flemish reuse network about its reselling of reusable goods with new survey data about disposal and acquisition behaviours of a representative sample of 1500 Flemish citizens. Using these data, we map the amount of reuse channelled through various exchange channels and calculate a reuse estimate (Total Reused Goods—TRG). In addition, we nuance its environmental impact through calculating its replacement rate. Our results reveal an important share of informal channels beyond formal channels. Moreover, a new estimate of 33.8kg reuse/capita is calculated for Flanders, which is 6.3 times higher than the current estimate of 5.4kg reuse/capita. Furthermore, only 28% of reusable goods prevent the acquisition of new goods. This new methodology is the first to calculate a comprehensive reuse measure which may form the basis for new regional reuse indicators.

Italian midwives in Europe: a qualitative study on the experiences of professional migration.

To explore the reasons for Italian midwives' decision to migrate, and their lived professional and emotional experiences. A descriptive phenomenological study was conducted recruiting Italian midwives who were working abroad in European countries. We offered a telephone or web interview. Two researchers conducted, audio-recorded, and fully transcribed the interviews and other two researchers, independently, performed a content analysis. Thirty-two midwives having professional experiences in the UK, Ireland, Germany, Switzerland, and Spain were interviewed. Five themes emerged: 1) Education, 2) Migration decision-making, 3) Professional experience abroad, 4) Midwives' perceptions of their role, 5) Satisfaction versus desire to return. Our findings show a general dissatisfaction with Italian job opportunities in terms both of access to employment and work conditions. This scenario is complicated by the status of the professional midwifery in Italy. Stakeholders should ensure that the migration of Italian midwives is not synonymous with dispersion but is a channel of professional growth and mutual exchange.

Virtual forums for public accountability: How internet and communication technologies are influencing citizen interactions with a local government

AbstractPublic accountability forums can be useful mechanisms for ensuring that governments are responsive to the perspectives, preferences, and needs of citizens. This study explores how ICTs are affecting public accountability forums and how citizens interact with elected and appointed government officials. A case study of a municipal government in Ontario, Canada, describes how a virtual public accountability forum emerged and functioned based on social media data and interviews with public officials. The case demonstrates that social media can facilitate new channels of interaction between citizens and public officials. Key features of these virtual forums include anonymous participation, variable duration, and dynamic audience size. The case also demonstrates that the demand for information provision within accountability relationships is not just a singular type of ex‐post exchange. There is a new channel of information exchange that is continuous and malleable because it can evolve and change instantaneously over ICTs.

Compositional Grounded Language for Agent Communication in Reinforcement Learning Environment

<p align="justify">In a context of constant evolution of technologies for scientific, economic and social purposes, Artificial Intelligence (AI) and Internet of Things (IoT) have seen significant progress over the past few years. As much as Human-Machine interactions are needed and tasks automation is undeniable, it is important that electronic devices (computers, cars, sensors…) could also communicate with humans just as well as they communicate together. The emergence of automated training and neural networks marked the beginning of a new conversational capability for the machines, illustrated with chat-bots. Nonetheless, using this technology is not sufficient, as they often give inappropriate or unrelated answers, usually when the subject changes. To improve this technology, the problem of defining a communication language constructed from scratch is addressed, in the intention to give machines the possibility to create a new and adapted exchange channel between them. Equipping each machine with a sound emitting system which accompany each individual or collective goal accomplishment, the convergence toward a common ‘’language’’ is analyzed, exactly as it is supposed to have happened for humans in the past. By constraining the language to satisfy the two main human language properties of being ground-based and of compositionality, rapidly converging evolution of syntactic communication is obtained, opening the way of a meaningful language between machines.</p>

Comparative Thermohydraulic and Energy-Economic Characteristics of Heat Exchange in Round and Rectangular Channels Under Laminar and Turbulent Heat Carrier Flow Conditions

Comparative Thermohydraulic and Energy-Economic Characteristics of Heat Exchange in Round and Rectangular Channels Under Laminar and Turbulent Heat Carrier Flow Conditions

Numerical study of heat transfer, flow fields, turbulent length scales, and anisotropy in corrugated heat exchanger channels

In this study, we report on large eddy simulation (LES) of convectively dominated heat transfer in a corrugated heat exchanger channel using the computational fluid dynamics toolbox, OpenFOAM. A chevron pattern domain with 63 contact points is used to represent the conditions in a real plate heat exchanger (PHE). The unsteady nature of the flow is elucidated using visualization techniques based on volume rendering of temperature and iso surfaces of vorticity defined using the λ2-criterion and contours of wall shear stress and wall heat flux to illustrate the heat transfer process. Global surface averaged temperature and pressure drop are extracted from the LES on successively finer grids, approaching direct numerical simulation resolution, to increase the understanding of grid resolution requirements for LES in PHEs. Industry standard Reynolds-averaged Navier–Stokes simulations are compared to the LES results along selected profiles to demonstrate similarities and differences between the two techniques. The differences detected are further investigated using anisotropy invariant mapping, energy spectra, and turbulence length scale distributions. Significant differences between the model classes are detected and detailed. Moreover, the LES resolution requirements for the flow and the heat transfer processes are found to be different with the latter being more severe.

Experimental study of a pilot unit of a ground regenerator for greenhouses

The object of research: the process of heat exchange in a packing in the form of a dense layer of crushed stone as part of a thermal regenerator designed to utilize the low-grade heat of the air in a greenhouse.
 Investigated problem: increasing the efficiency of air heat accumulation in the greenhouse during the daytime by a regenerative heat exchanger with a granular packing. Conducting experimental tests of regenerator models with a packing in the form of a dense layer of granular material under natural conditions is necessary to improve the design and optimize technological parameters.
 The main scientific results: the analysis of temperature curves of air changes at the inlet and outlet of the regenerator installed in the mock-up greenhouse with a volume of 0.25 m3, and the packing material was carried out. During the heating period of the nozzle, the accumulated heat was Q=8•104 J, which can be used when the temperature in the greenhouse decreases. During the pause, the loss from the heat exchange channel to the environment is 48,000 J. The duration of the period was 358 min, while the average heat flux corresponded to 2.2 W. Heat losses during the pause period are significant due to its duration, however, the average heat transfer coefficient has a low value of k=2.3 W/m2K, so strengthening the insulation of the heat exchange channel is irrational.
 The area of practical use of the results of the study: greenhouses, allowing the possibility of installing additional heat exchange equipment.
 Innovative technological product: the innovativeness of the technical solution is determined by the possibility of using the heat of the air in the greenhouse and the implementation of contact heat exchange between the air flow and the packing particles. The design of the regenerator, the simplicity of its manufacture and operation, as well as the efficiency of air heat accumulation in the greenhouse during the daytime, allow to recommend it for use in greenhouse farms.
 The scope of the innovative technological product: regenerative heat exchangers with a dense layer of granular material for the utilization of low-grade air flows generated in food production enterprises, ventilation systems and greenhouses

AMBA AHB Bus with Multiple Masters Using VHDL

This article depicts execution of DDR3 controller of AMBA Bus with four experts is portrayed in this paper. DDR3 controller is associated with the AMBA AHB Bus. It empowers development of squares of information from fringe to memory, memory to fringe, memory to memory, and fringe to fringe. This development of information lessens the heap on the processor. A DDR3 controller saves power in a framework by placing the CPU in a low force state. An AXI 4.0 execution in SOC configuration lessens the limits of correspondence by decreasing information rates. Proposed configuration utilizes AXI 4.0 conventions with memory regulator interface. AXI 4.0 convention upholds various IDs and channel handshaking rather than judge. In AXI 4.0, five individual exchange channels is proposed to convey in different expert and various slave frameworks so numerous bosses can discuss all the while with numerous slaves and wonderful parallelism is accomplished. All the control circuitry is synthesized using Xilinx 13.1 and simulation waveforms are achieved by using Modelsim 6.5e.

Method for calculating the coefficient of hydraulic resistance of a coaxial heat exchanger with rough walls

A method for calculating the coefficient of hydraulic resistance of a coaxial heat exchanger with different roughness of opposite walls is proposed. According to the technique, the annular section of the heat exchanger channel is divided by a line of zero shear stress into two non-interacting annular layers. The balance equations in the layers and the channel together with the condition of matching the velocities of the layers on the zero shear stresses line form a closed system of equations. The solution of the system allows calculating the coefficient of hydraulic resistance of the channel as a whole, the position of the line of zero shear stresses, average velocities in each of the layers, the value of the second constant of the universal velocity profile. The method was verified in several ways, which showed the maximum deviation of the calculated values from the data of other authors and the results of our experiments, no more than 7%. In our experiments, we used three two-dimensional artificial roughness profiles: rectangular, trapezoidal, and triangular.

Public Opinion Management of Public Crisis Events in the New Media Era — Taking 3.21 China Eastern Airlines Flight Accident as an Example

In the era of new media, press conferences and TV news are no longer the only channels for information exchange. Communication software, major public accounts, online forums and other ways have become the channel of the masses to have their voices to be heard. After the occurrence of public crisis, public opinion based management becomes a link that the government is required to attach importance to. Positive public opinion management can greatly reduce the negative impact of public crisis events. Therefore, the authority, accuracy and timeliness of information disclosure become the key factors. The government, the media and the masses should form a multi-management subject, which can be led by government with multi-party mode to control the trend of public opinion. In addition, the government should uphold the people-oriented concept, and do a good job in psychological counseling for the victims' families, witnesses, rescue workers and other groups to prevent intensified public opinion. In the new media era, the government should be candid and relative, take the initiative, give positive guidance and interact well, so as to form a good ecological environment for online public opinion, improve the handling efficiency of public crisis events, and thus promoting social solidarity and enhancing the ability of the government to handle some issues.