Exchanger Network Research Articles

Qualitative Interviews with Stakeholders in Herbal Pharmacovigilance and Recommendations for Best Practices to be Applied Worldwide.

The use of herbal products globally is substantial, but varying definitions and regulatory frameworks have led to differences in their status as medicinal products and in approaches to monitoring their safety. This article explores the current landscape of herbal pharmacovigilance, drawing insights from interviews with global experts in the field, and offers recommendations for best practices to enhance the safety and benefit-to-harm balance of herbal products. This study comprised semi-structured interviews with members of the International Society of Pharmacovigilance-Herbal and Traditional Medicines Special Interest Group and the Nutrivigilance Information Exchange Network, recruited using purposive sampling. Data were stored and coded using NVIVO® and analysed thematically using a qualitative inductive approach. Sixteen participants from 11 countries were interviewed, revealing diverse regulatory approaches and challenges in herbal pharmacovigilance. Key themes included legal status, awareness, identification and coding of herbal products, pre-/post-marketing product control, reporting of adverse drug reactions, causality assessment and signals of herbal products. This study yielded five general recommendations to further improve herbal pharmacovigilance worldwide. This study offers an overview of the global landscape of herbal pharmacovigilance, highlighting challenges in monitoring herbal products and presenting universal recommendations. These recommendations encompass increasing awareness, enhancing education and improving legislative frameworks. Given the growing use of herbal products, the implementation of strong pharmacovigilance practices is crucial to ensure consumer safety.

Equilibrium modelling of steam gasification of PKS system and CO2 sorption using CaO: A digitalized parametric and techno-economic analysis

The conversion of palm oil waste into energy can complement the energy mix with renewable energy and bring economic benefits to the palm oil industry. A process simulation model for palm kernel shell (PKS) steam gasification for H2-enriched syngas with the integration of CO2 capturing using CaO has been investigated using Aspen Plus V10®. Techno-economic and energy analyses have also been conducted to identify energy-saving opportunities for commercialization. The effect of process variables, including reactor temperature (600–800 °C), Steam/PKS ratio (0.5–2 wt/wt), and CaO/PKS ratio (0–1.5 wt/wt), have been determined, with the predicted results compared to the reported experimental data. H2 concentration has been increased with 76–78 vol% with the temperature elevation from 650 to 750 °C. Additionally, a substantial increase in H2 content from 68 to 72vol% was observed when the steam flow rate was increased from 0.5 to 1.5. Conversely, the CO2 concentration decreased from 25 to 8vol% as the adsorbent ratio was raised from 0.5 to 1.5. The techno-economic analysis showed that the capital investment is $4.11 million, and the operating cost is $3.89 million per year, which is also very high due to the high raw material costs. In the case of energy, saving that 3.03 and 1.513 Gcal/hr can be saved in terms of utilities and gas cooling that economized the process which shows that utilization of these in heat exchange networks can significantly reduce costs, with up to 78 % savings in heat exchanger capital and 35 % in total energy consumption. The energy potential could be harnessed through the digitalization of the process.

Utilization and exchange of jade in western China during the late Longshan Era (2300∼1800 BC): Evidence from Lajia site, Minhe County, Qinghai Province

During the Longshan Era, the production and use of jade, including bi-discs, cong-tubes, axes, and other artifacts, were prevalent in several regions situated along the middle and upper reaches of the Yellow River. The exchanges and interactions between them have been discussed by many scholars. Among these societies that valued jades, Ganqing region of Qijia Culture is regarded as a significant source of some valuable jade materials like nephrite. The non-destructive testing of jade artifacts excavated from the Lajia site, a central settlement of the Qijia culture, revealed a comparatively high proportion of nephrite, as well as a rich variety of materials. This demonstrates the acknowledgment and utilization of jade materials, particularly the valuable nephrite in the surrounding region. The availability of jade materials and uncomplicated jade processing created the conditions for household production of jade. Needs for ritual and exchange are considered as potiential driving force behind such production. Evidences of producing and using amazonite artifacts and trumpet-shaped tubes suggests long-distance exchange and influence of jade artifacts/materials. The circulation of nephrite materials may also have been embedded in this network of exchange.

Integration of distributed PV into smart grids: A comprehensive analysis for Germany

Modern smart grids typically combine physical and communication networks for efficient information exchange and innovative applications. Aligned with digitalization and advancements in smart grids, the integration of photovoltaic (PV) systems comprises a variety of regulatory and technological aspects. However, no previous study has conducted an extensive and systematic analysis of the PV-grid integration framework, particularly for one country. To fill this gap, this paper uses Germany as an example to present a comprehensive, state-of-the-art analysis of integrating distributed PV systems into smart grids, focusing on the regulation and technical implementation of the German Smart Meter Infrastructure and PV control interfaces. Starting from a standardization perspective, this analysis utilizes the Smart Grid Architecture Model to identify crucial roles, components and processes specifically in Germany. Furthermore, it outlines the current implementation of PV integration into distribution networks at a national level. The results of this study show the overall complexity of PV integration in the smart grid context, confirm the feasibility of the German integration approach, and highlight the necessity of deploying standardized information models and communication technologies. These key findings can help market participants with different roles to identify potential technical bottlenecks or other critical points in the regulation and technical implementation. For instance, the proposed in-depth analysis framework provides an orientation for characterizing the PV integration or, more generally, the grid integration scenario of renewables in other countries.

EFSA's activities on emerging risks in 2022

Abstract The main objectives of EFSA's activities on emerging risks encompass: (i) conducting activities to identify emerging risks; (ii) developing and improving emerging risk identification (ERI) methodologies and approaches; and (iii) communicating identified issues and risks. The outcome of these activities equips EFSA to anticipate forthcoming challenges in the continuously evolving landscape of risk assessment. EFSA networks of knowledge contributing to the emerging risks identification activity include the Emerging Risks Exchange Network (EREN), the Stakeholder Discussion Group on Emerging Risks (StaDG‐ER), EFSA's scientific units, the scientific panels, the Scientific Committee and their working groups. The current technical report summarises the activities of all groups involved in the emerging risk identification procedure, the issues identified in the course of 2022, the emerging risk identification methodologies being developed, and the collaborative activities. In total, 13 potential emerging issues were discussed in 2022 and two were concluded to be emerging risks. The potential issues were classified according to the hazard. The year 2022 marks a turn in EFSA's activities on emerging risk identification. To achieve strategic objective no. 2 ‘Ensure preparedness for future risks analysis needs’ of the EFSA Strategy 2027, a new process ‘Environmental scanning and strategic options definition’ has been developed. The process adds to the already existing emerging risks analysis workflow a second workflow that is more forward‐looking, to deal with horizon scanning in the areas of food and feed safety, plant health and animal health. Similarly to the emerging risks analysis workflow, the new workflow for horizon scanning strongly relies on partnership to be prepared for future challenges, build resilience, and proactively shape the future in a one‐health approach.

Navigating inter-team competition: How information broker teams achieve team innovation.

Organizations are increasingly using teams to stimulate innovation. Often, these teams share knowledge and information with each other to help achieve their goals, while also competing for resources and striving to outperform each other. Importantly, based on their industry, the nature of work, or prior history, some teams may face more competition from peer teams than others. Our research examines how teams' competitive relations with other teams in the organization operate in tandem with their collaborative inter-team information exchange relations in impacting their innovation. Using two studies-a field study of 73 knowledge-intensive teams in high-tech engineering firms and a team-based network experimental study of 162 teams-we find that a high degree of overall competition with many peer teams reduces a focal team's ability to acquire and utilize diverse knowledge from these teams (i.e., inter-team knowledge integration), thereby hindering team innovation. However, applying insights from network structural hole theory, we find that when a focal team occupies a brokerage position in the inter-team information exchange network, this can help buffer the effects of competition in getting access to knowledge resources from other teams, thus enabling their innovation. Additionally, we find that focal broker teams' dealmaking and network obstruction behaviors explain these effects. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Evaluating synthetic fuel production: A case study on the influence of electricity and CO2 price variations

To combat climate change, we need to reduce emissions from the transport sector. Synthetic fuels are a long-term solution for aviation, maritime and heavy machinery. Large-scale use requires cost-effectiveness, efficient production and resilience to price changes. In this case study, we simultaneously optimize the cell voltage of the solid oxide electrolysis cell, the heat exchanger network and the heat supply of a PtL-plant. PtL-efficiency and production costs are used as objectives to generate multiple Pareto fronts for future price scenarios. The results show that the sensitivity to price changes has different impacts on design and operating parameters, which can lead to unattractive solution domains in the Pareto front. Currently, synthetic fuels can be produced at 1.83–2.36 €/kg. In the best case, at 1.42–1.97 €/kg and 3.88–4.28 €/kg in the worst case. This paper supports decision-makers in planning PtL-plants to ensure sustainable synthetic fuel availability on a global scale.

Maritime hinterlands and interregional interaction at Late Antique Kekova Adası, Türkiye

How do resource-poor island communities develop networks to ensure their supply of foodstuffs and basic commodities? The growth of the Late Antique (5th-7th century CE) town at Kekova Adası on the southern Turkish coast of Lycia offers an instructive case study. Underwater survey along the town’s harbor front yielded large quantities of amphoras, utilitarian and fine pottery, and ceramic building materials that testify to local consumption and transshipment activities on the island. The origins of these materials serve as proxy for the networks of exchange that underpinned life on Kekova Adası. Yet because many of the most common amphora and other pottery types were produced over wide areas of many hundreds of kilometers of coast in Late Antiquity, ceramic petrography is necessary to determine or more precisely define the origins of these materials and, in turn, the shape of the networks through which they moved. The results reveal that the inhabitants of Kekova Adası developed a hinterland for supply by sea that encompassed the coastal plain around Limyra some 40 km to the east as well as, seemingly, across the open sea to the southwest corner of Cyprus. While most of the bulk processed agricultural goods (particularly wine and oil) carried in these amphoras, and the ceramic building materials and other imported wares, derived from these two regions, this hinterland also intersected with larger networks of exchange that brought amphoras as well as fine and cooking wares from across the Levant, Cilicia, the east Aegean, and the northeast Peloponnese. This pattern articulates the integration and mutual interdependence of Kekova Adası’s local network with the particularly busy interregional route that supplied major urban centers and the state during this period. In the process, the case study highlights the necessity of ceramic petrography as a means of precisely reconstructing such networks.

Replicated multistage interconnection networks: QoS evaluation for parallel and distributed computing

Introduction to big data becomes very important with dealing in high-performance parallel distributed computing, especially in those systems where communication among a number of processors is required. The current paper takes into consideration different topologies for the Shuffle Exchange Network (SEN) in order to attain optimal data transfer among such scenarios. SEN topologies are a key feature in connecting several processors and implementing the data transfer among them where a single processor fails to handle the load. The study hereby reports in the performance, reliability, and cost analysis of these topologies. These topologies, some of which are advocated to have better performance in many studies, include replicated networks. Our research demystifies claims made in earlier papers that replicated networks have inflated reliability and higher costs due to their additional links. Researchers are therefore guided on accurate performance data that will lead them to make optimum choices of SEN topologies for targeted applications. These findings further highlight that the trade-offs between reliability and cost must be carefully considered during network design so as to arrive at better results for big data communication and computation in parallel and distributed systems. This work provides important insights into the correct evaluation of SEN topologies, helping to correct the misleading facts and to have better network selection for various real-time application realizations.

Muonium state exchange dynamics in n -type GaAs

Muonium (Mu), a pseudoisotope of hydrogen with a positively charged muon in place of the proton, takes the form Mu+,0,− (like isolated hydrogen, i.e., H+,0,−) in semiconductors. The specifics of the charge state depend on the local electronic environment of the host. After initial muon implantation, generated Mu centers interact with free charge carriers and electronic spins, transition between sites, and form a dynamic network of state exchange. We identified the model of Mu dynamics in n-type GaAs using the density matrix simulation method and photoexcited muon spin spectroscopy technique. Fitting to the dark and illuminated μSR data provided transition rates between Mu states, revealing the underlying mechanisms at play between the Mu centers (cf. isolated H) and the host. Deduced capture/scattering cross sections of the Mu states reflected the microscopic dynamics of Mu. Illumination studies enabled us to measure interactions between Mu and minority carriers, which would be unavailable in dark measurements without heating. The methodology developed in this study may be applied to other semiconductor systems for a deeper understanding of the Mu state exchange dynamics. Published by the American Physical Society 2024

Intelligent construction and optimization based on the heatsep method of a supercritical CO2 brayton cycle driven by a solar power tower system

The current progress in tower-based solar thermal concentrators and receivers enables achieving temperatures within the required range of 500–700 °C for the S–CO2 Brayton cycle. Within this temperature range, the efficiency of the S–CO2 Brayton cycle exceeds that of conventional steam power cycles. This study applies the S–CO2 Brayton cycle to concentrated power generation systems, emphasizing structural and parameter optimization. By utilizing the operational parameters of tower-based solar thermal power generation as boundary conditions and maximizing specific power as the optimization objective, various configurations derived from a maximum of two fundamental cycles are systematically enumerated. Subsequently, an intelligent algorithm optimizes the power cycle flow and parameters for each structure, further optimizing the heat exchanger network. The findings reveal that the optimized configuration shares a common heating and cooling process. This optimization yields a specific power increase of 14.62 kJ/kg compared to the reference case, indicating a 13.26 % enhancement. Additionally, the cycle efficiency improves to 47.45 %, marking a 28.52 % increase. The overall system efficiency for the solar power tower system reaches 32.03 %, with an exergy efficiency of 32.19 %.

A novel polygeneration process integrated into a gas turbine cycle toward an environmentally friendly framework; Application of a comprehensive 4E study

In this study, a new environmentally friendly polygeneration scheme is proposed in arrangement with a gas turbine cycle. In order to investigate the proposed system, parametric research is conducted in conjunction with the energy, exergy, economic, and environmental assessments (4E study). The simulation is done in the Aspen HYSYS software. According to the design condition results, the total energy efficiency and exergy efficiency, thermoeconomic indicators such as total unit cost of product and total product cost, as well as the waste heat recovery ratio in the heat exchanger network of the evaporator, are 57.81 %, 63.47 %, 25.12 $/GJ, 0.1019 $/kWh, and 49.67 %, respectively. In addition, it is determined that the total exergy destruction rate and the exergy destruction intensity for the proposed process are 204470 kW and 1.33 kWD/KWP, respectively. The gas turbine cycle with a share of 60 %, exhibits the highest irreversibility. Based on economic estimates, the project requires a total investment of $636209804. In addition, considering an annual income of 159850224 $, the payback period is 3.98 years. Lastly, the environmental evaluation indicates that the proposed process has a carbon footprint equal to 0.356 kgCO2/kWh and a total carbon dioxide emission of 67241.36 kg/h.

A novel intermediate heat exchange intensified extractive pressure-swing distillation process for efficiently separating n-hexane-tetrahydrofuran-ethanol

The new intensified strategy can be used in special distillation processes to achieve energy savings. Through analyzing the influence of different extractants and pressure on the separation performance of n-hexane-tetrahydrofuran-ethanol. system, extractive pressure-swing distillation process (EPSD) using dimethyl sulfoxide as extractant was proposed. Multi-objective optimization was performed to definite the best operating parameters of EPSD. Based on the phenomenon that the temperature of high-temperature column top is lower than low-temperature column bottom, making it impossible to perform traditional thermal integration, an intermediate heat exchange intensified process (IHE-EPSD) was developed. The performance influencing factors and heat exchange network of IHE-EPSD were analyzed to obtained the optimal IHE-EPSD process. Three heat integration schemes of the IHE-EPSD were designed to further save energy consumption. Finally, the processes were assessed from economy, energy, environment and exergy. The results indicate that the IHE-EPSD process exhibits excellent separation performance, achieving the efficient separation of n-hexane-tetrahydrofuran-ethanol.

Zebrafish from the Alps to Sicily: The 4th Italian Zebrafish Meeting in Palermo.

The 4th Italian Zebrafish Meeting took place in Palermo from February 7 to 9, 2024. The primary aim of this meeting was to bring together a diverse group of principal investigators, young researchers, facility managers, commercial vendors, and others to provide an important forum for presentation and discussion of the most innovative and exciting scientific research currently ongoing in Italy using the zebrafish model. Nonetheless, the meeting program has been conceived to allow the dissemination of cutting-edge scientific research across a wide range of topics and to shed light on its future directions, without geographical boundaries. Indeed, people from various parts of the world joined the meeting, and 210 participants presented their latest work in talks and posters. Importantly, the meeting had designated time to foster open scientific exchange and informal networking opportunities among participants of all career stages, thus allowing initiation of new collaborations and strengthening of existing partnerships. The meeting was a tremendous success as testified by the highest participation ever since the first meeting of the series in 2017, coupled with the highly positive satisfaction rating expressed by the attendants. The full program and detailed information about the meeting can be found on the dedicated website at https://itazebrafishmeeting.wixsite.com/izm2024.

Synthesis of flexible inter-plant heat exchanger networks: A decomposition method considering intermedium fluid circles

The traditional methods for synthesizing flexible heat exchanger networks (HENs) are not directly applicable to inter-plant HEN challenges, primarily due to the spread of system uncertainty across plants via intermedium fluid circles. This complicates the synthesis process significantly. To tackle this issue, this study proposes a decomposed stepwise methodology to facilitate the flexible synthesis of the inter-plant HENs performing indirect heat integration. A decomposition strategy is proposed to divide the overall network into manageable sub-networks by dissecting the intermedium fluid circles. To address the variability in intermedium fluid temperatures, a temperature fluctuation analysis approach is developed and a heuristic rule is introduced to maintain the temperature feasibility of the intermedium fluids. To ensure adequate flexibility and cost-effectiveness of the designed networks, flexibility analysis and network retrofit steps are conducted through model-based optimization techniques. The efficacy of the method is demonstrated through two case studies, showing its potential in achieving the desired operational flexibility for inter-plant HENs.

AI-enabled sports-system peer-to-peer energy exchange network for remote areas in the digital economy

In remote areas, particularly in developing countries, there is a growing interest in off-grid solar PV systems for their ability to provide clean and affordable electricity. However, these systems often face limitations in powering essential amenities, including sports facilities, due to restricted capabilities and inadequate battery storage. To address these challenges and promote energy independence, this paper proposes an AI-enabled sports-system peer-to-peer (P2P) energy exchange network within the digital economy. This innovative system leverages AI to optimize energy distribution specifically for sports-related infrastructures, ensuring efficient use of solar power and improved energy availability for both recreational and community needs. The proposed P2P network operates on a three-part Internet of Things (IoT) framework, facilitating automatic energy sharing among interconnected systems. This approach not only enhances the performance of existing solar power setups but also ensures that energy demands for sports facilities are met effectively. Feasibility studies of this system reveal promising outcomes, including a 13.67% increase in community energy independence and a 12.20% reduction in overall energy consumption. The AI-powered sports-system network demonstrates its potential to support sustainable development and improve the quality of life in remote areas by integrating sports and energy needs within the digital economy context.

Game theoretic approach for the synthesis and optimization of economically optimal coalitions in integrated renewable energy and polygeneration networks

This study presents the generation of an integrated resource network that encompasses a bioenergy supply chain and a polygeneration hub. The resource network is designed using a superstructure that comprises 3 layers. The first layer is a supply chain network of seasonally available renewable and non-renewable energy sources and is connected to the second layer by a transport system comprised of rail, road, and pipeline. The second layer, which is the polygeneration hub, comprises a boiler to produce high-pressure steam, steam turbines for generating power, a multi-effect evaporation system for desalinating salt-water and an absorption refrigeration system to produce chilled water. The option of connecting the boiler to a solar-thermal and heat storage subnetwork for feedwater pre-heating is included in the second layer. Piping and electrical cables connect the polygeneration layer to the third layer, which comprises industrial heat demand, represented by heat exchanger network, and electrical power demand. The model is applied to a case study in which the subnetworks in the overall integrated superstructure layers are considered as individual players in an industrial symbioses network with the possibility to be in a cooperative game. The objective function of the model, which is represented as a mixed integer nonlinear programming model, involves the minimization of the summation of the players' marginal contribution, with equal weighting applied for each player, to the coalition's total annual cost. The result obtained involves preference for a coalition among participating subnetworks that include combined heat and power, multi-effect evaporation, and heat exchanger network.

Modeling and design of a combined electrified steam methane reforming-pressure swing adsorption process

Steam methane reforming (SMR) is the most widely used hydrogen (H2) production method, converting natural gas and steam into H2 and carbon dioxide (CO2). SMR is a mature industrial technology that burns fossil fuels to provide heat to the endothermic reforming reaction and to generate steam, which contributes to the production of greenhouse gas emissions. In order to reduce heating-based emissions, an electrically-heated steam methane reforming process has been proposed. Conventional SMR uses a packed bed catalyst and receives heat through radiation from hot flames in the surrounding furnace; on the other hand, an electrified SMR employs a washcoated catalyst, and is resistively-heated through the wall of the reactor coil. To gain further insight into the scalability of hydrogen production processes using electrically-heated reformers, this paper takes experimental data from an electrified reformer built at UCLA, extracts kinetic parameters, and uses these parameters to model and scale up a hydrogen production plant with a hydrogen production capacity of 231 kg/h (2607 Nm3/h). The simulated plant includes a reformer, two water gas shift reactors, pressure swing adsorption (PSA) for separation, and a heat exchange network to make steam for the reformer. A two-column-PSA process is dynamically modeled to output 99% H2 purity, and the pressures necessary for separation and H2 recovery are calculated using steady-state simulation data. A sensitivity analysis is conducted for the most energy-efficient H2 production conditions (e.g., operating pressure, heat flux), and CO2 production amounts are compared to a conventional SMR process, demonstrating that electrified SMR can potentially be a significantly cleaner alternative. The optimization of electrified reformers must target high mass and heat transfer along the full length of the reformer to achieve near full methane conversion that will minimize off-gas generation from the PSA unit.

A novel optimization framework integrating multiple initialization, automatic topologization and MINLP reduction to accelerate large-scale heat exchanger network synthesis

Ensuring the solution feasibility and achieving an acceptable solution time for the non-deterministic polynomial-time hard (NP-hard) problem of heat exchanger network (HEN) synthesis is still challenging. In this study, we developed a novel optimization framework for efficiently solving large-scale HEN synthesis problems to obtain near global optimal solutions, simultaneously addressing the solution's infeasibility and time. The optimization framework consists of a multiple initial HEN design model (M-INI model), a new distance-based auto structure transformer (A-STR transformer), and a reduced non-linear programming model (R-NLP model). The M-INI model generates various HEN designs based on pinch analysis by varying the minimum approach temperature and the modes of stream splitting and mixing. The A-STR transformer is first proposed to automatically convert various HEN designs into associated superstructure-based topologies as multiple initial starting points for accelerating the solution of the R-NLP model. A strategy for approximating the temperature difference calculation is further applied to reduce the computational loads. Four case studies were conducted using the proposed method to minimize the total annual cost (TAC). The solutions of general cases 1 and 2 are almost equal to the best results in the literature, while the solution time is reduced by 98.7 % and 99.8 %, respectively, which demonstrates the performance of the proposed method. Especially, the method was applied to two practical industrial HEN cases: a large-scale low-grade heat recovery system and a crude distillation unit. The results of large-scale case 3 show that the optimal solution near the global optimal solution only requires 251.7 s. Case 4 includes pre-splitting in scenario A and free splitting in scenario B. Compared to scenario A, the TAC and solution time in scenario B were reduced by 33.9 % and 93.1 %, indicating that the pre-splitting strategy excludes the optimal from the search space. The proposed novel optimization framework demonstrates the efficiency and applicability of handling large-scale HEN synthesis problems. It can also guide engineers in the design of a large-scale HEN with lower costs and effort.

Introduction: By Land and by Sea: Understanding Cultural and Other Networks of Exchange in Mongol Eurasia and Beyond

Introduction: By Land and by Sea: Understanding Cultural and Other Networks of Exchange in Mongol Eurasia and Beyond