Closed-loop Configuration Research Articles

Centrifugal Compressor Surge in Innovative Heat Pump: Fluid Dynamic and Vibrational Analysis

Abstract In the current energy scenario, it is necessary to reduce fossil fuel consumption to achieve the far-sighted and stringent decarbonization goals. To date, heat is mainly produced through fossil fuels. Alternatively, electrically driven heat pumps can exploit renewable power to recover environmental and waste heat, offering energy efficient and environmentally friendly heating and cooling for applications ranging from domestic and commercial buildings to process industries. For this reason, they are expected to play a primary role in complementing or displacing natural gas boilers in the residential and industrial sectors in the near future. Centrifugal compressors are already used as prime movers of the working fluid in heat pumps, thanks to their industrial replicability, compact size, affordable costs, and good performance in terms of efficiency and low noise. However, they are subject to instabilities such as surge and stall like any other dynamic compressor and these phenomena develop quite differently than in classic open-loop systems such as gas turbines. In fact, such peculiarity is mainly due to the closed-loop configuration with real gases in two-phase conditions, occurring in typical heat pump cycles. In addition, heat exchangers also contribute to make these phenomena different from what is commonly studied. Compressor surge in closed-loop heat pump systems has received lower attention than other applications by the engineering community, lacking dedicated experimental characterization, and clear exposition of the phenomenon. The aim of this paper is to experimentally investigate the behavior of a centrifugal compressor installed into an innovative close loop heat pump system under stable and unstable conditions from both vibrational and fluid-dynamic points of view. The impact of the main process parameters on the evolution of the instability is shown, highlighting how surge cycles change by varying system operating conditions. The energy contents of surge cycles and pressure fluctuations are highlighted, using data postprocessing techniques such as fast Fourier transform and phase locked average. The vibro-acoustic analysis enrich the comprehension of the phenomena. The experimental results shown in this paper can be a basis for the future development of validated mathematical models of closed-loop heat pumps systems equipped with dynamic compressors operating under stable and unstable operating conditions.

Discriminative Power of the Flow through Cell Dissolution Tester in Predicting the In Vivo Performance of Pentoxifylline SR Product under Fed and Fasting Conditions

This study explored, for the first time the role of different designs of the Flow-Through-Cell (FTC, USP IV) dissolution Tester in predicting the in-vivo performance of Pentoxifylline (PTX) sustained-release (SR) market product, under fed & fasting conditions. Release studies of Trental® SR 400 mg (Sanofi, Egypt), were carried-out in the FTC under different conditions, including: different volumes / compositions of release media, variable FTC flow patterns as well as applying open / closed loop configuration setups. Pharmacokinetic (PK) data, obtained from literature, were converted to in-vivo fraction-absorbed [FA] using Wagner-Nelson (WN) method. A 1:1 IVIVC was investigated by comparing PTX fraction-dissolved [FD] under different FTC release designs versus calculated [FA]. Predicted PK parameters were evaluated, and compared with actual data, with estimation of prediction-error (PE%). The suggested FTC design; a closed-loop setup, with turbulent-flow pattern of the dissolution medium; provided the most acceptable PTX release according to USP labeled limits (USP 27). Also, results showed that PTX release was pronouncedly increased in a finite-volume of gradient-buffer system rather than water, which guarantee complete resemblance to GIT environment. This release design presented the most predictive IVIVC model with PTX in-vivo performance under fasting / fed states, with acceptable PE% values in terms of Cmax and AUCs. A suggested FTC design is proposed as an alternative dissolution model in the official USP-monograph for PTX SR products.Graphical

Determination of the ground-state hyperfine splitting of trapped 171Yb+ ions

We present the determination of the ground-state hyperfine splitting (νHFS) in laser-cooled 171Yb+ ions using our microwave quantum frequency standard (QFS). Employing Ramsey spectroscopy in a closed-loop measurement configuration, we have achieved a νHFS value of 12 642 812 118 469.0(8) mHz with a fractional uncertainty of 6.6×10−14. This result aligns with previously reported values and represents the highest accuracy reported to date for such measurements conducted in a single-shot closed-loop configuration, without averaging over multiple dates. The development of this accurate 171Yb+ microwave QFS holds promise as a transportable time-frequency reference for satellite navigation systems.

Configuration synthesis and screening method for multiple closed-loop unit tandem mechanisms

To broaden the methods of configuration synthesis, this study proposes a new method for configuration synthesis and screening of multiple closed-loop unit tandem mechanisms. Firstly, some closed-loop configurations are taken as basic units, and the closed-loop basic units are synthesized in series under the condition of considering the basic unit types, contacts, and input and output relationships. Secondly, the connectivity of the mechanism is obtained by weighting the adjacency matrix, and the entropy weight method is used for the first time to establish a comprehensive evaluation index coefficient to assess the quality of the mechanism. Then, an improved simulated annealing-greedy algorithm is proposed and an algorithm software screening platform is built to screen mechanisms. Finally, the multi-fingered grasper is used as design case to verify the practicality of the proposed configuration synthesis and screening method. This study can provide a reference for theoretical research on the configuration synthesis and screening methods of multiple closed-loop unit tandem mechanisms.

Correlation to predict thermal characteristics of pulsating heat pipes with long evaporator section

In terms of employing closed-loop pulsating heat pipes as heat transfer devices in solar water heaters, the evaporator should be extremely long according to the length of the solar collector. However, there is a noticeable shortage of Semi-Empirical Correlations for predicting the thermal performance of extra-long closed-loop pulsating heat pipes utilized for heat absorption within solar collectors. The primary objective of this study was to formulate a Semi-Empirical Correlation specifically designed for predicting the thermal efficiency in extra-long closed-loop pulsating heat pipe configurations. This study extensively examined the thermal efficiency of a comprehensive design of closed-loop pulsating heat pipe samples when implemented in an evacuated-tube solar water heater system strategically designed for individual households. The specified maximum length for the evaporator section of the closed-loop pulsating heat pipes is set at 1.50 m, in contrast to the conventional design, which typically features an evaporator section of approximately 0.15 m. Furthermore, the investigation encompasses a number of sets, varying as one, two, and four. Therefore, a Semi-Empirical Correlation derived from the experimental data concerning seven pertinent non-dimensional parameters is presented, demonstrating a standard deviation percentage of 4.4 %. Among these parameters, the number of sets emerged as the most influential, inducing a maximum percentage change in the heat rate of water of 20.47 %. Moreover, compared with other studies utilizing pulsating heat pipes in solar water heaters, the correlation exhibited a 1.52 % error. These findings suggest that the developed Semi-Empirical Correlation is a valuable tool for predicting the thermal performance of an extra-long closed-loop pulsating heat pipe. It is particularly well suited for estimating the thermal behavior of closed-loop pulsating heat pipes with extended configurations, showcasing its enhanced accuracy and relevance in capturing the distinction of heat transfer in extra-long closed-loop pulsating heat pipe systems.

A closed-loop kinematic approach to Self-Calibration of joint offset for multi-branched robots

Kinematic accuracy is fundamental for the performance of multi-branched robots, which are composed of multiple branches that collaborate to manipulate. Among those various factors affecting kinematic accuracy, the joint offset is the most significant contributor due to misalignment in component assembly. In this work, we present a general, fast, and low-cost approach based on closed-loop kinematics to calibrate joint offsets of multi-branched robots. A dedicated calibration board connects the distal ends of branches to form closed-loop configurations. The identification model is derived based on the closed-loop kinematic differential model. The observable indexes of multiple closed-loop are integrated to optimize the calibration board’s poses, and joint offsets are identified simultaneously. To enhance the robustness of the calibration outcomes against joint backlash noise, the Kolmogornov-Smirnov(K-S) test is performed on multiple sets of identification results to verify that joint offset obeys normal distribution. Experiments on a quadruped showed significantly improved foot-tip position accuracy.

Phase sensitive slow light in semiconductor quantum dots

This article presents a theoretical investigation of phase-controlled propagation of slow light under an electromagnetically induced transparency window in a multilayered one-dimensional photonic crystal with semiconductor quantum dot nanostructures as defects. To achieve the electromagnetically induced transparency window, a setup utilizes a faint probe laser pulse alongside two powerful control laser beams arranged in a closed-loop cascade configuration. In this arrangement, a significant Kerr nonlinearity, approximately on the scale of ∼10−13m2/V2, is discerned within the quantum dot nanostructures at a probe wavelength of 1.55 μm. It is observed that both the amplitude and the phase relationship of the control Rabi frequencies play crucial roles in governing the dynamics of the group velocity of the probe field in the quantum dot nanostructures. Under the regime of electromagnetically induced transparency, the group velocity of the probe field is significantly reduced, approximately by a factor of 103 times as compared to the light speed in free space. These findings hold promise for potential applications in nonlinear optics.

Validation of a Hybrid Domain Overlapping Coupling Between SAM and CFD Against the TALL-3D Transients

The system thermal-hydraulic (STH) code SAM has been coupled to the computational fluid dynamics (CFD) code Simcenter STARCCM+ utilizing a hybrid domain overlapping coupling method in space and an explicit coupling in time. The coupling aims to extend the STH code’s applicability to scenarios where local momentum and energy transfers are important yet difficult for STH standalone models to capture, such as three-dimensional (3D) mixing and thermal stratification. The coupling method’s numerical stability was previously verified against multiple test cases including two closed-loop configurations, and it was validated against a double T-junction experiment with 3D scalar mixing. In the present work, the method is validated against the TALL-3D STH/CFD coupling benchmark facility. TALL-3D is a liquid-metal facility with a large, pool-type enclosure (test section) that exhibits 3D flow effects to be modeled by a CFD code. The rest of the system exhibits approximately one-dimensional behavior that is well predicted by a STH code. First, a STAR-CCM+ CFD model of the 3D test section is validated against experimental temperature data. Then a SAM-STARCCM+ coupled model is validated against six different TALL-3D steady states and includes SAM standalone results for comparison. Last, the coupled model is validated against two TALL-3D transients: one exhibiting flow reversal in the test section and one exhibiting nonlinear, limit cycle oscillations (LCOs). For the first transient, the SAM-STARCCM+ coupled model properly predicts an increase in the test section’s inlet temperature during flow reversal, and this increase is not predicted by the SAM standalone model. The coupled model also better predicts initial flow recovery and subsequent oscillations as the system approaches a final natural circulation state. For the second transient, no true final steady state is observed due to LCOs. Neither the SAM-STARCCM+ coupled model nor the SAM standalone model can perfectly capture the experiment’s changing oscillation frequency during the transient. Nevertheless, the coupled model does reproduce the general oscillatory feedback observed. This is a significant achievement because the present coupling only uses an explicit coupling in time, as opposed to a tighter, semi-implicit coupling. In comparison, STH/CFD coupling efforts previously performed by other authors required a semi-implicit coupling to obtain similar results to this work. The strengths of the novel coupling scheme validated in the present paper lie in the superior convergence characteristics and the much simpler, nonintrusive implementation.

#1416 Extracorporeal removal of per- and polyfluoroalkyl substances (PFAS) by hemoadsorption: in vitro kinetic model

Abstract Background and Aims Per- and polyfluoroalkyl substances (PFAS) are known water pollutants leading to potential public health consequences. High blood levels of PFAS have been associated with several pathological conditions including testicular and kidney cancer. Classic extracorporeal therapies have demonstrated limited efficiency and new approaches should be explored. In this study we studied the possible role of hemoadsorption to achieve a fast, safe and effective removal of PFAS from blood in patients with high blood levels. Method We developed an in vitro model of hemoadsorption to test the potential of PFAS removal by extracorporeal treatment. We recirculated a highly polluted batch of water (4 liters) through HA380 sorbent cartridge (Jafron Medical, Zuhai, China) for 120 minutes at a flow of 150 mL/min in a closed loop configuration (Fig. 1). We collected samples at different time points and analyzed 39 different PFAS compounds. Results For the PFAS compounds with concentrations significantly above normal, we observed a removal ratio close to 90% already within the first 60 minutes of circulation leading to almost complete elimination of all pollutants at 120 minutes (Fig. 2). RR is remarkably high already in the very early moments of the adsorption process. This is likely dependent on the interaction of the different solutes with the molecular structure of the sorbent. Conclusion The in vitro model of hemoadsorption suggests the possible application in vivo of this technique to reduce/normalize the concentrations of PFAS in patients exposed to water or environmental pollution.

#1983 In vitro iohexol adsorption in cartridges with mesoporous styrene-divinylbenzene sorbent

Abstract Background and Aims Patients with pre-existing chronic kidney disease (CKD) present the highest risk of developing contrast-associated acute kidney injury (CA-AKI). Iodinated contrast agents such as iohexol (molecular weight 821 Da) don't bind to proteins and are easily removed by hemodialysis filters. However, the session time necessary to remove approximately 75% of the injected iohexol load is around six hours. Due to lack of evidence, current guidelines do not recommend to start hemodialysis in CKD patients in conservative management after the administration of iodinated contrast media to prevent or mitigate CA-AKI. Still, a strong rationale supports the removal of iodinated contrast media because of its nephrotoxicity. In this study, we aimed to investigate the capability of a mesoporous styrene-divinylbenzene sorbent to bind iohexol in vitro. Method We used 1,000 mL of saline solution spiked with 40 mL of iohexol 350 mg/mL in a closed-loop configuration. Iohexol concentration was 14 mg/mL. The amount of the iodinated radiocontrast was proportional to the amount used in complex percutaneous coronary interventions (worst-case scenario), around 200 mL, in a 70 kg person with an estimated blood volume of 5,000 mL. The solution circulated through a HA380 mini-module cartridge filled with 75g of mesoporous styrene-divinylbenzene sorbent beads at 250 ml/min. The experiment was carried out twice with the same setup. Samples were collected at eight-time points (0, 5, 10, 15, 20, 30, 40, and 60 minutes) from the reservoir to measure iohexol concentration. The analysis of the samples was carried out in duplicate. The removal ratio (RR) was calculated considering the initial concentration (C(0)) and the variation of the concentration during the experiment (C(t), where t is the time point), as follows: $RR( \% ) = \frac{{C( 0 ) - C( t )}}{{C( 0 )}}100$ Results In the first experiment, the removal ratios after 5, 30, and 60 minutes were 23.4%, 45.8%, and 52.9%, respectively on average. In the second experiment, the reduction ratios after 5, 30, and 60 minutes were 23.4%, 45.5%, and 53.1%, respectively on average. After 30 minutes, the adsorption curved plateaued, indicating cartridge saturation (Fig. 2). Conclusion This in vitro model demonstrated that HA380 sorbent cartridge was effective in removing iohexol. The use of hemoadsorption as a strategy to remove iodinated contrast media warrants further investigation because of its clinical potential to reduce the exposure to nephrotoxic contrast agents and CA-AKI.

#2512 Behaviour of Human Proenkephalin A 119-159 (penKid) in an in vitro model of hemoadsorption

Abstract Background and Aims Proenkephalin A 119-159 (penKid) is a stable surrogate marker for enkephalins (endogenous opioids regulating kidney function). Different clinical studies have shown severity-dependent increased penKid levels in patients with sepsis-associated acute kidney injury (AKI), indicating that penKid can be used for prediction and diagnosis of AKI and need of renal replacement therapy (RRT) and even subclinical forms of AKI. In the absence of targeted therapies, organ support in terms of RRT is the ultimate treatment in severe AKI cases. Hemoadsorption is utilized as an adjunctive therapy in septic patients. The aim of this study is to define the penKid removal ratio in conditions of in vitro hemoadsorption (HA) using a synthetic microporous hemo-compatible resin. Method The lyophilized peptide was solved in 20 mM Dipotassium phosphate, 6 mM Disodium EDTA [pH 8], avoiding concentrations higher than 1 mg/mL. The compound was diluted in 50 mL of plasma to ensure homogeneous distribution. A batch of blood of 1000 mL with adjusted hematocrit at 30% and albumin concentration of 3 g% was utilized. Blood was spiked with lyophilized synthetic penKid to achieve the target concentration of 600 pmol/L. Blood was adjusted for a volume of 1000 mL, maintained at 37° and continuously stirred during the experiment. HA was performed with QB = 150 mL/min in a closed-loop configuration. A sorbent minimodule of HA380 (Jafron, Zhuhai, People Republic of China) was utilized. Samples were taken at 5, 15, 30, 60 and 120 minutes from the initiation of the circulation. Total removal and reduction ratios were calculated to assess the adsorption. This procedure was repeated three times. Results Initial penKid concentrations in blood corresponded to the desired target. In the three experiments penKid concentrations displayed a consistent decrease that approached 75% removal ratio at 120 minutes (Figs 1 and 2). Minimal variability was observed confirming a consistent behavior of the interaction between the sorbent and the molecule. Conclusion The results suggest that penKid is effectively removed during hemoadsorption and its levels should be evaluated in light of these results when in vivo hemoadsorption is carried out in critically ill patients.

Methanol-based thermochemical energy storage (TCES) for district heating networks

With increasing volatility in natural gas markets and the need for residential heat, research for alternative thermal systems based on green hydrogen-based fuels is necessary. Massive implementation of hydrogen in the current fleet presents a challenge for the decarbonisation of conventional thermal processes. This paper presents the integration of green methanol from a seasonal thermochemical energy storage system (TCES) coupled with district heating networks (DHN). It allows for a solar-based storage and low-temperature heat generation from the exothermic discharge reaction. The system uses concentrated solar thermal energy to decompose methanol into syngas at moderate temperatures (<315 °C), reducing GHG emissions from combustion to meet residential heat. Its potential is assessed through an analysis of 458 rural municipalities in Spain, achieving a substitution of 3.1 % of the natural gas demand. The system allows the production of green fuels from syngas using an open-loop approach, offering new market pathways in primary sector. In a closed-loop configuration, roundtrip efficiencies exceeding 60 % and chemical conversion efficiencies exceeding 70 % are reached, resulting in a global efficiency of 12 % for the DHN and methanol-TCES. The results show a levelized cost of stored energy highly competitive with other storage systems (<200€/MWh), given its simplicity.

Techno-economic evaluation of transesterification processes for biodiesel production from low quality non-edible feedstocks: Process design and simulation

The global demand for fossil fuels has led to increased pollutant emissions and depleted fossil fuel resources. Biodiesel, a fossil fuel alternative, is widely produced via transesterification. This study assesses the techno-economic performances of three transesterification processes (alkaline, acid, and CaO catalytic) for biodiesel production from low-quality non-edible feedstocks. The study explores effects of elevated free fatty acids (FFAs) and oil/ethanol flow rates on these processes, focusing on their impact on yield, purity, economics and energy aspects. Aspen Plus® V10 software was used for simulations. Despite meeting international biodiesel standards, significant technical and economic variations exist among the processes. The acid catalytic process exhibits energy requirements surpassing those of alkaline and CaO catalytic processes by over 29.58%, leading to operational costs exceeding those of CaO catalysis by 13.11%. The study establishes CaO catalysis as the most feasible option due to its simplicity, adaptability, and substantial energy and cost reductions. By introducing a closed-loop blending setup configuration, the study reveals that CaO catalysis outperforms alkaline and acid catalysis, achieving 11.59% cost reduction and 13.31% energy decrease in closed-loop configurations. The overall results highlight the potential of non-edible feedstocks in biodiesel production for a more environmentally friendly and sustainable energy future.

Multi-line-of-sight Hartmann-Shack wavefront sensing based on image segmentation and K-means sorting

Multi-line-of-sight wavefront sensing, crucial for next-generation astronomy and laser applications, often increases system complexity by adding sensors. This research introduces, to the best of our knowledge, a novel method for multi-line-of-sight Hartmann-Shack wavefront sensing by using a single sensor, addressing challenges in centroid estimation and classification under atmospheric turbulence. This method contrasts with existing techniques that rely on multiple sensors, thereby reducing system complexity. Innovations include combining edge detection and peak extraction for precise centroid calculation, improved k-means clustering for robust centroid classification, and a centroid filling algorithm for subapertures with light loss. The method’s effectiveness was confirmed through simulations for a five-line-of-sight system and experimental setup for two-line and three-line-of-sight systems, demonstrating its potential in real atmospheric aberration correction conditions. Experimental findings indicate that, when implemented in a closed-loop configuration, the method significantly reduces wavefront residuals from 1 λ to 0.1 λ under authentic atmospheric turbulence conditions. Correspondingly, the quality of the far-field spot is enhanced by a factor of 2 to 4. These outcomes collectively highlight the method’s robust capability in enhancing optical system performance in environments characterized by genuine atmospheric turbulence.

Active vibration suppression of tetrachiral auxetic core sandwich panel with CFRP skin: An RVE homogenization-assisted finite element approach

Free vibration as well as the controlled dynamic response of moderately-thick smart sandwich panel are numerically explored considering the size effect of chiral unit cells at the microscopic level, with the help of RVE-assisted-finite element (FE) approach. In this scientific article, the authors have made a debut attempt to analyse the smart damping behaviour of a tetrachiral-type auxetic core sandwich panel (with carbon/epoxy skin) deploying a real-time based constant velocity feedback controller in a closed loop configuration. Effective anisotropic elastic properties as well as the reduced stiffness matrix of the cellular core layer have been determined by using RVE-FE based full-scale homogenization technique in ANSYS® platform. Dynamic equation of motion governing the plate structure, has been derived using an energy-based variational principle, and further solved with the help of a quadratic interpolation based finite element method. The mid-plane kinematics of the plate structure are assumed to follow first order shear deformation theory (FSDT). A number of numerical examples have been solved and compared with previously published literature to ensure the consistency of the present homogenization-cum-numerical approach. From the observation it is found that, the natural frequency and the controlled dynamic response of tetrachiral-type sandwich structure are very much sensitive towards the geometry (cell wall thickness, ligament length etc.) and architecture of the unit cell of the auxetic core. Also, a comparison study has been performed between tetrachiral auxetic smart sandwich and regular hexagonal honeycomb smart sandwich plate, which confirms about the mechanical advantage of the former over the later configuration, due to the existence of out-of-plane negative Poisson's ratio (NPR) and axial-shear coupling stiffness. Afterwards, a few additional numerical examples have been solved by changing different influencing parameters of the auxetic core sandwich plate and important results are reported in the article.

Hsa_circ_0036872 has an important promotional effect in enhancing osteogenesis of dental pulp stem cells by regulating the miR-143-3p/IGF2 axis

BackgroundCircular RNAs (circRNAs), an extremely stable group of RNAs, possess a covalent closed-loop configuration. Numerous studies have highlighted the involvement of circRNAs in physiological processes and the development of various diseases. The present study aimed to investigate how circRNA regulates the osteogenic differentiation of human dental pulp stem cells (hDPSCs). MethodsWe isolated hDPSCs from dental pulp and used next-generation sequencing analysis to determine the differentially-expressed circRNAs during osteogenic differentiation. Bioinformatics and dual-luciferase reporter assays identified the downstream targets. The role of circRNAs in osteogenic differentiation was further confirmed through the use of heterotopic bone models. ResultsWe found that hsa_circ_0036872 expression was increased during osteogenic differentiation of hDPSCs, and downregulation of hsa_circ_0036872 inhibited their osteogenic differentiation. Dual-luciferase reporter assays showed that both miR-143-3p and IGF2 were downstream targets of hsa_circ_0036872. Overexpression of IGF2 or inhibition of miR-143-3p restored the osteogenic differentiation ability of hDPSCs after silencing hsa_circ_0036872. Overexpression of IGF2 reversed the inhibitory effect of miR-143-3p on osteogenic differentiation. ConclusionTaken together, our results show that hsa_circ_0036872 exerts an important promotional effect in enhancing the osteogenesis of dental pulp stem cells by regulating the miR-143-3p/IGF2 axis. These data suggest a novel therapeutic strategy for osteoporosis treatment and periodontal tissue regeneration.

Investigations into Higher-Frequency Hysteresis Current Controller for Supraharmonic Hybrid Active Filters

Hysteresis current controllers (HCCs) are extensively used in low-frequency power inverters and active power filters. Very little is known about their strengths and weaknesses when applied at supraharmonic frequencies. The major concern regarding the use of HCCs is their variable and uncontrollable switching frequencies. This results in difficulties in filter design, high switching losses, and the possibility of resonance conditions with power system elements. In this article, investigations are conducted on the application of HCCs in a hybrid filter for a 6 kHz matrix converter (MC)-coupled supraharmonic load. The effects of the MC-coupled load and VSC switches on the HCC’s switching frequency are analyzed. A novel mathematical model for obtaining a fixed-frequency HCC is presented. The model is verified in open- and closed-loop HCC control configurations for a three-phase hybrid active power filter (HAPF). Fast Fourier transform (FFT) analysis of the supply current after the implementation of the novel HCC-HAPF showed 2.31% of the 50 Hz fundamental. The analysis is verified in a MATLAB/Simulink environment.

Pricing decisions of online and offline dual-channel supply chains considering data resource mining

Data resources, a fundamental component in the digital economy, play a vital role for businesses aiming to establish a lasting competitive edge. A company's data resources can uniquely influence the decisions surrounding products and services within the supply chain. The integrated dual-channel supply chain (DCSC) involves direct online channels utilized by manufacturing service providers alongside offline channels, such as physical retail stores, managed by sales service integrators. The DCSC is capable of performing second-stage data mining services in accordance with the sold products and customer services after the product sales are completed. Subsequently, data resource mining can be achieved through a cross-channel approach. As such, considering the exploration of cross-channel data resources, this study strives to formulate a structure for a dual-channel closed-loop supply chain. Furthermore, utilizing concepts from the Stackelberg and Nash equilibrium game theories, it delves into the analysis of pricing decisions and profit allocation. This examination encompasses distinct closed-loop supply chain configurations, viewed through the lenses of both centralized and decentralized decision-making approaches. In addition, the effects of cross-channel data mining and channel consumption preferences on supply chain decisions are analyzed, and the analysis is conducted in combination with numerical examples. As evidenced by the findings in this investigation, cross-channel data resource mining, consumer channel preference, and the data mining value conversion rate can prominently affect the formulation of pricing strategies and the distribution of profits in closed-loop supply chains. The potential value of data resources can lead to the generation of “external incentives” following the strategy of data resource mining. Furthermore, the data resource mining strategy is promising in stimulating the growth of the product and service markets. Finally, the overall profit of the supply chain is increased with the increase in the efficiency of data resource conversion. Enhancements in the efficacy of data resource conversion correspondingly lead to heightened overall profits within the supply chain.

Bidirectional Multi-Device Daisy Chain Communication Architecture and Verification Based on UART Serial Communication Protocol

This paper proposes an innovative bidirectional multi-device daisy chain communication framework grounded in the Universal Asynchronous Receiver-Transmitter (UART) serial communication protocol. This intricate architecture employs four distinct physical Input/Output (IO) interfaces to facilitate dynamic serial communication amongst multiple devices. These devices can be conjoined in a sequential daisy chain or in a closed-loop ring configuration. To further enhance the functionality, our system incorporates a unique mechanism that leverages randomized device codes for rapid address allocation. This not only facilitates directional communication but also supports broad-spectrum broadcast transmissions. An exhaustive simulation of the said protocol was carried out utilizing Proteus software in tandem with a Microcontroller Unit (MCU) model. Critical parameters such as communication response delay, the cumulative failure rate of transmissions, and the isolated failure rate of individual data packets between nodes were meticulously evaluated. Preliminary findings underscore the protocol's potential in fostering cost-effective and dependable communication amongst a plethora of devices. The practicality and versatility of this system manifest prominently in arenas like cluster robot command, robotic automation, and holistic environmental monitoring.

A multi-period multi-objective closed-loop blood supply chain configuration and optimisation under disruption

The COVID-19 pandemic has highlighted the stability of the blood supply chain in case of interruption and other emergencies. Blood is a precious and perishable substance, and any disruption in its supply can cause serious consequences. Current research on the blood supply chain mostly focuses on a multi-objective perspective, and rarely involves both multi-objective and multi-period methods simultaneously. Therefore, we develop a multi-period multi-objective closed-loop blood supply chain model that considers disruptions and uncertainties of demand and recovery, aiming at achieving a balance among various objectives, and coordination of various periods. Fuzzy chance-constraint, meta-heuristic approaches and exact solution (CLPEX) are adopted to mitigate the impact of uncertainties and calculate the optimal solution of a calculating case. The calculation outcomes indicate that: With regard to economic costs and social benefit, the multi-period system is better than the single-period system; the comprehensive performance of the multi-target system is better than that of the single-target system; and the multi-period multi-objective system is more in line with the real situation. Meanwhile, the mitigation strategies, such as maintaining emergency inventory and implementing lateral transshipment, can significantly enhance the performance of the system in disruptions. This paper mainly contributes the follows: Firstly, it provides a reference for configuration and optimisation of a cross-region closed-loop supply chain under disruptions and uncertainties. Secondly, the comprehensive trade-off of multi-objective and multi-period in this paper is especially suitable for perishable production with short cycles, large fluctuations of supply and demand.