Cyclic Process Research Articles

Permafrost Degradation Induces the Abrupt Changes of Vegetation NDVI in the Northern Hemisphere

AbstractPermafrost, widely distributed in the Northern Hemisphere, plays a vital role in regulating heat and moisture cycles within ecosystems. In the last four decades, due to global warming, permafrost degradation has accelerated significantly in high latitudes and altitudes. However, the impact of permafrost degradation on vegetation remains poorly understood to date. Based on active layer thickness (ALT) monitoring data, meteorological data and normalized difference vegetation index (NDVI) data, we found that most ALT‐monitored sites in the Northern Hemisphere show an increasing trend in NDVI and ALT. This suggests an overall increase in NDVI from 1980 to 2021 while permafrost degradation has been occurring. Permafrost degradation positively influences NDVI growth, with the intensity of the effects varying across land cover types and permafrost regions. Furthermore, based on Mann‐Kendall trend test, we detected abrupt changes in NDVI and environmental factors, further confirming that there is a strong consistency between the abrupt changes of ALT and NDVI, and the consistency between the abrupt change events of ALT and NDVI is stronger than that of air temperature and precipitation. These findings work toward a better comprehending of permafrost effects on vegetation growth in the context of climate change.

Biomass erosion and its effect on heat carrying performance of alumina heat carrier during multiple cycle sintering in solar photothermal coupled with biomass gasification

Biomass coupled with solar photothermal gasification technology is an efficient technology using solar to provide energy by heat carrier for biomass gasification. However, the heat carrier that transferred heat to the biomass feedstock can be eroded by the effects of biomass ash, with the erosion problem worsening as the number of cycles increased. The erosion and adhesion caused by multiple sintering of corn stalk ash (CSA) to heat carrier particles (Al2O3) were investigated. K and Si elements in CSA are the main elements that erode Al2O3 particles, and their erosion depth increases with the number of sintering cycles. The erosion process of CSA on heat carriers deepens with multi-sintering, but the infiltration behavior of CSA can be fairly prevented due to the generation of high fusion minerals during erosion. The infiltration characteristics of CSA change abruptly upon contact, influencing the erosion behavior during the cyclic sintering process.

Abstract Cyclic Functional Relation and Taxonomies of Cyclic Signals Mathematical Models: Construction, Definitions and Properties

This work is devoted to the procedure of the construction of an abstract cyclic functional relation, which summarizes and extends the known results for a cyclically correlated random process and a cyclic (cyclically distributed) random process to the case of arbitrary cyclic functional relations. Two alternative definitions of the abstract cyclic functional relation are given, and the fundamental properties of its cyclic and phase structures are presented. The theorem on the invariance of cyclicity attributes of an abstract cyclic functional relation to shifts of its argument, and which are determined by the rhythm function of this functional relation, is formulated and proved. This theorem gives the sufficient and necessary conditions that the rhythm function of an abstract cyclic functional relation must satisfy. By specifying the range of values and attributes of the cyclicity of an abstract cyclic functional relation, the definitions of important classes of cyclic functional relations are formulated. A deductive approach to building a wide system of taxonomies of classes of deterministic, stochastic, fuzzy and interval cyclic functional relations as potential mathematical models of cyclic signals is demonstrated. A comparative analysis of an abstract cyclic functional relation with the known mathematical models of cyclic signals was carried out. The results obtained in the article significantly expand and systematize the mathematical tools of the description of cyclic signals and are the basis for the development of effective model-based technologies for processing and computer simulation of signals with a cyclic space-time structure.

Response processes to water quality changes driven by the dynamic regeneration of the surface microlayer film in slow-flowing freshwater bodies

The freshwater surface microlayer film (SMF) is a dynamically evolving micro-ecosystem closely related to water quality and microbial growth in water. However, the mechanisms of dynamic regeneration of SMF after their destruction and their impacts on the aquatic environment are still largely unknown. Herein, we modeled the dynamic processes of SMF destruction and recovery in the natural environment by constructing a water-SMF ecosystem. Chemical and biological changes in the dynamic regeneration of SMF were investigated. The results showed that the dynamic regeneration of SMF was very fast, with a regeneration thickness of up to 300±50 μm in two days, and at the same time, it would rapidly enrich organic matter and Fe ions. In addition, the cyclic dynamic regeneration process of SMF is significantly correlated with the surge metabolic growth of microorganisms associated with organic matter metabolism (e.g., Methylophilus, Nevskia) and iron-redox-associated (e.g., Curvibacter). The experimental results suggest that the microbial-mediated process of iron-organic matter coupled oxidation-reduction in SMF may be another important mechanism driving water quality changes. Overall, our study provides valuable theoretical guidance for predicting changes in water quality in slow-flowing water bodies.

Enhanced plasma etching using nonlinear parameter evolution

This study explores the development and characterization of plasma etching for sub-micron features using a nonlinear evolution of parameter in a three-step cyclic Bosch process. Comparing this nonlinear approach with traditional linear parameter evolution, we aimed to address issues such as bowing at the top of the features and narrowing at the bottom. Constant parameter etching produced tapered profiles, undercutting, and non-uniform scallops due to particle deflection. Linear parameter evolution partially mitigated these problems by balancing etch and deposition cycles and gradually increasing radio frequency power, achieving high selectivity to the photoresist. One nonlinear exponential evolution method resulted in a higher etch rate but caused slight damage to the top-side wall, while the etch depth was reduced. The other nonlinear method balanced the etch and deposition steps more effectively, achieving a comparable etch rate and selectivity to the linear method. Further optimization of this second method led to improved vertical profiles and controlled scallops, achieving greater depth, smoother sidewalls, and higher etch rates. This optimized technique successfully fabricated high aspect ratio periodic sub-micron structures with excellent uniformity across the wafer, demonstrating its potential for achieving even higher aspect ratios with thicker masks.

Analysis of pyroelectric properties in quenched NBT-BT composition

Quenching has recently demonstrated its efficacy in elevating the ferroelectric to relaxor phase transition temperature (TFR) in 0.94Na0.5Bi0.5TiO3-0.06BaTiO3 (NBT-6BT). Consequently, the current investigation comprehensively examines the pyroelectric properties of quenched NBT-6BT. The pyroelectric coefficient is measured using the Byer-Roundy method, incorporating a strategic approach to mitigate the risk of overestimation by implementing cyclic heating and cooling. Quenching enhances the depolarization temperature (Td) by approximately 40 °C, quantified through the temperature-dependent pyroelectric current density (Ip). The maximum pyroelectric current (52nA) and voltage (200V) responses to thermal cycling (15s heating/cooling) were observed in quenched NBT-6BT. The voltage sensitivity figures of merit were equivalent for both furnace-cooled and quenched NBT-6BT. The assessment of pyroelectric energy storage involved charging a 48 nF capacitor in 180s, resulting in a maximum voltage of 38V. The outcomes strongly endorse the quenched NBT-6BT as an efficient pyroelectric material, showcasing promising attributes for applications in sensing and energy harvesting across a broad temperature range.

Joining of the functionally gradient friction material to the backing plate for wind turbines using sinter-brazing technique

This study explores the sinter brazing of friction materials to the backing plate, aiming to enhance the bonding strength of the wind turbine mechanical braking system. Sinter brazing, a hybrid process of integrating sintering and brazing in a single heat cycle to offer a robust method for joining friction materials to backing plates under high temperatures. The microstructure establishes the evidence of strong metallurgical bond between the friction material and the backing plate. An average hardness of 133.2HV was obtained at the interface and the shear strength obtained was 74.3 N/mm2.

Microwave-powered integrated carbon capture and utilisation (ICCU) for methane production with rapid temperature response from minimal thermal inertia

Integrated CO2 capture and utilisation (ICCU), emerging as an effective approach for achieving global carbon neutrality goals, demonstrates its potential through the transformation of captured CO2 into valuable methane and the concurrent hydrogen storage via methanation reaction. However, traditional ICCU strategies are heavily reliant on conventional thermal conduction heating, and the in-situ methanation process is constrained by reaction thermodynamics, posing significant challenges. In this study, we introduce for the first time a novel microwave-powered system, employing a clean and efficient energy source that offers rapid heating and on-demand operation and acts as an external field enhancement method in the ICCU-methanation procedure. The designed blend of Ni-loaded CaO and carbon nanotubes (CNTs) integrates the functions of CO2 adsorption, hydrogenation catalysis, and microwave absorbing ability. This novel approach achieved a CO2 capture capacity of 3.31 mmol gDFM-1 with CO2 conversion and CH4 selectivity reaching 71.01 % and 98.17 %, respectively, at a nickel loading of 20 wt%. We also propose a possible rate enhancement mechanism for the microwave-powered ICCU-methanation cyclic process compared to conventional methods. The microwave-powered system can substantially enhance overall efficiency by swiftly responding to temperature swings, thus reducing processing time in ICCU-methanation cycles.

Effect of nickle on cerium oxide support to develop cyclic catalytic methane decomposition followed by CO2 gasification

Catalytic methane decomposition (CMD) offers an eco-friendly method to produce COx-free hydrogen and solid carbon. An innovative approach for catalyst regeneration involves utilizing CO2 as a reactant to produce CO via the Reverse Boudouard Reaction, which serves as a valuable feedstock for various chemicals and fuels. This study aims to investigate the role and interaction of Ni nanoparticles on cerium oxide support by comparing two catalysts: one synthesized via the conventional impregnation method (Imp) and the other through solution combustion synthesis (SCS). Both catalysts containing the same Ni loading of 5 wt% and were tested under identical conditions. Comprehensive characterization techniques, including XRD, H2 and O2 TPR, TEM, SEM, XPS, and Raman spectroscopy, were employed to elucidate the observed performances. The SCS catalyst resulted in smaller Ni nanoparticles with stronger metal-support interaction. Observations revealed both tip and base carbon growth for the SCS catalyst, whereas the Imp catalyst predominantly characterized by tip growth. For the SCS catalyst, carbon nanofibers and nanotubes were observed, and both appeared active in carbon CO2 gasification. For the Imp catalyst, more crystalline carbon is observed. The amount of carbon produced was much more and managed to cover the entire catalyst. For SCS carbon coverage was partial. Two rates of CO2 gasification were observed depending on the extent of carbon coverage. Across all tested temperatures and space velocities, the catalyst prepared by impregnation exhibited higher reaction rates. The Imp catalyst demonstrated 15 % higher CMD and 29 % more generated carbon than SCS. This work demonstrated the critical role of key factors influencing the catalytic performance of this cyclic process. This includes the Ni nanoparticle size and distribution, the metal-support interaction's strength, and the graphitic carbon's nature.

Les violences conjugales dans les couples appartenant aux « minorités sexuelles » : quelles causes traumatologiques ?

IntroductionMost prevention and awareness-raising programs are heteronormative and do not take into account the presence of violence in sexual minority couples. MethodThe aim of this study is to review the literature on domestic violence in sexual minority couples in relation to any traumatic experiences that may be causes and/or consequences. ResultsA link between childhood trauma, stress or a combination of the two in the perpetration of domestic violence in sexual minorities is highlighted just like the recent creation of typologies in these couples. DiscussionSuffering from significant methodological biases, nevertheless, these studies, which are all too rare, deserve to highlight phenomena that should be better appreciated. Although domestic violence in minority couples appears to be similar to violence in heterosexual couples, two-way violence is more prevalent. This bidirectional violence could largely be the result of a cyclical process of violence from childhood to adulthood, moving from intrafamilial trauma in childhood to societal stress related to sexual orientation in adolescence and finally to mutual violence within the couple in adulthood. ConclusionThe origins of the perpetration of domestic violence in a sexual minority couple appear to be linked to: the consequences, particularly psychological, of stress related to sexual minorities, which mediate the subsequent violence; the cycle of violence with the internalisation of an appropriate violent relationship model, thus representing a generational transmission and a pattern of repetition; the presence of bidirectional violence, also involving defence and reaction behaviours, accentuated by traumatic experiences or stress related to minorities.

Soundness unknotted: An efficient soundness checking algorithm for arbitrary cyclic process models by loosening loops

Although domain experts usually create business process models, these models can still contain errors. For this reason, research and practice establish criteria for process models to provide confidence in the correctness or correct behavior of processes. One widespread criterion is soundness, which guarantees the absence of deadlocks and lacks of synchronization. Checking soundness of process models is not trivial. However, cyclic process models additionally increase the complexity to check soundness. This paper presents a novel approach for verifying soundness that has an efficient cubic worst-case runtime behavior, even for arbitrary cyclic process models. This approach relies on three key techniques — loop conversion, loop reduction, and loop decomposition — to convert any cyclic process model into a set of acyclic process models. Using this approach, we have developed five straightforward rules to verify the soundness, reusing existing approaches for checking soundness of acyclic models.

The evaluation of hydrogen production of a multistage cooling system's performance

In the present research, a new cycle of scramjet open recuperator cooling to produce power and hydrogen is presented. In which, the power generation subsection uses the waste heat in the scramjet cooling process as a cycle heat source and produces electric power. In this research, some of the power generated in the cycle is used to power a Polymer Electrolyte Membrane (PEM) electrolyzer that produces hydrogen. An analysis of the energy and exergy has been conducted to assess the system's performance. With a fuel mass flow rate of 0.45 kg/s, the cooling capacity of the system is 10.2 MW, net power production is 4.1 MW, and 45.1 kg/h of hydrogen is produced. The exergy analysis revealed that the PEM electrolyzer had the highest exergy loss at over 48%, followed by the first cooling path at over 32%. The energy and exergy efficiency of the system are 14.2% and 19.2%, respectively. The parametric study indicated that increasing the mass flow rate leads to higher power production and cooling capacity. Additionally, at a constant fuel mass flow rate, power production increases with higher pressure behind the pump.

Experimental investigation on the low temperature performance of a novel three-pressure air source heat pump

As people’s demand for living comfort grows, the problems of conventional air source heat pumps (ASHPs) become more prominent in low-temperature and high-humidity environments: heating performance attenuation, low defrosting efficiency, and significant impact on indoor thermal comfort during defrosting. Existing literature usually focuses on only one or two of these issues, and few comprehensively cover them. Based on current literature, this paper proposes a novel multi-functional three-pressure ASHP that can cover the above three aspects with a series–parallel combination structure featuring dual compressors and dual cycles. This design enables switching multiple heating and defrosting modes through valve combination and improves performance through two-stage throttling and subcooling. An experimental platform is constructed to evaluate its operational performance. The experimental results show that: (1) In heating modes, the average heating capacity of the three-pressure cycle heating mode is 2897.15 W, and the average COP is 2.47, while these two data of the conventional cycle heating mode are 2393.65 W and 2.4, and the improvement rates of 20.4 % and 2.9 %, respectively. It also extends the high-efficiency heating period of the system, enables rapid heating at start-up, increases compressor suction and discharge pressure, and improvs system stability. (2) In defrosting modes, compared with the conventional defrosting cycle, the three-pressure defrosting cycle raises the condensation temperature faster, reduces the defrosting time from 448 s to 265 s (40.8 % shorter). The auxiliary defrosting cycle has little effect on indoor thermal comfort and less defrosting power consumption, with the power saving rate as high as 44.6 %. Overall, the novel three-pressure ASHP has a unique and innovative structure, significantly optimizing performance under low-temperature and frosting conditions and improving energy efficiency and comfort. The results of this study provide a new solution concept for the future development of ASHPs, offering significant reference value for further development and application.

Oscillatory airflow through the hypopharyngeal and supraglottic airway

Exercise-induced laryngeal obstruction (EILO) is a known cause of exertional dyspnoea, characterised by paradoxical inward collapse of laryngeal tissues. The pathophysiological mechanisms of EILO remain to be fully established, but insufficient mechanical resistance of laryngeal tissues to air-induced loads is hypothesised. It is understood that airflow and anatomic configurations of the airway play a key role in the wall pressure distribution of the larynx. While breathing is a cyclic process with directional changes of airflow, the literature is confined to steady, unidirectional airflow. It is necessary to assess the role of oscillatory airflow on the loads on the laryngeal airway. This study investigates the effect of oscillatory airflow on the laryngeal flow fields and air-induced loads. A computational fluid dynamics model of the upper respiratory tract (URT) is developed using the Reynolds-averaged Navier-Stokes equations. Five oscillatory airflow cases through a single geometry are considered, utilising sinusoidal breathing cycles with different breathing frequencies (24, 32 and 40 breaths per minute) and peak inspiratory flow rates (96, 168 and 240 L/min). Results include the airflow velocity distribution in the URT, and the air-induced pressure and forces. It is demonstrated that inspiratory velocity distribution varies with breathing frequency and intensity. The force acting on the URT walls are in-phase with the airflow rate and therefore exhibit quasi-steady behaviour. These findings are also reflected in the force vectors acting on the aryepiglottic folds and indicate that air-induced closure of the supraglottis in EILO is influenced by the breathing intensity rather than the breathing frequency.

Introducing synthetic thermostable RNase inhibitors to single-cell RNA-seq

Single-cell RNA-sequencing (scRNAseq) is revolutionizing biomedicine, propelled by advances in methodology, ease of use, and cost reduction of library preparation. Over the past decade, there have been remarkable technical improvements in most aspects of single-cell transcriptomics. Yet, little to no progress has been made in advancing RNase inhibition despite maintained RNA integrity being critical during cell collection, storage, and cDNA library generation. Here, we demonstrate that a synthetic thermostable RNase inhibitor (SEQURNA) yields single-cell libraries of equal or superior quality compared to ubiquitously used protein-based recombinant RNase inhibitors (RRIs). Importantly, the synthetic RNase inhibitor provides additional unique improvements in reproducibility and throughput, enables new experimental workflows including retained RNase inhibition throughout heat cycles, and can reduce the need for dry-ice transports. In summary, replacing RRIs represents a substantial advancement in the field of single-cell transcriptomics.

An inverse ferroelastic type phase transition and electric properties in bis(ethylenediammonium)tetrachlorozincate chloride crystal

Here we present TGA, DSC, dielectric studies and polarized microscopy observations of bis-ethylenediammonium tetrachlorozinc dichloride. In our studies, we found a high-temperature first-order phase transition at about 478/470 K for the heating/cooling cycle, respectively. The reversibility of the phase transition was detected by DSC and dielectric measurements and also by polarized microscopy observations. The appearance of a ferroelastic-type domain structure phase above the phase transition temperature indicates a reduction in symmetry during the heating cycle. The domain walls observed in the (100) plane are characteristic of a ferroelastic-type phase transition and can be classified as mmmF2/m Aizu species. The reduction in symmetry above the phase transition temperature allows us to classify the phase transition at 476 K as a "reverse" type. Dielectric studies in the frequency range of 40 Hz - 8 MHz allowed to estimate the activation energy for conduction and relaxation processes both with increasing and decreasing temperature. Activation energies obtained both from conductivity (σdc) measured in the temperature range from 445 to 485 K and relaxation process are practically the same both for low- and high-temperature phases as well. Taking into account the results for all directions (a, b, c) and all temperatures, conductivity is 10−7 – 10−4 S/m and is within the range characteristic for semiconductors (10−8 – 106) S/m. The conductivity and relaxation activation energies determined for the directions (a, b, c) have values in the range from 0.58 to 3.7 eV, which are also within the range characteristic for semiconductors. Electrical properties show clearly anisotropic character of the studied material.

Cross-cultural design in costume: case study on totemic symbols of China and Thailand

Cross-cultural design has emerged as a pivotal domain of significance within the context of globalization. In the field of cross-cultural design, designers are tasked with addressing user requirements and identity characteristic contexts across diverse cultural backgrounds, aiming to achieve enhanced service delivery and cultural dissemination outcomes. Nonetheless, the landscape of contemporary fashion design research exhibits a noticeable dearth in studies that effectively integrate with cross-cultural design. This study selects the iconic cultural symbols of the Chinese loong (dragon) and Thai naga as case subjects, embarking upon research that employs costume design as a medium and bridge for cross-cultural design and communication. The research methodology integrates qualitative and quantitative approaches, including field investigations, participatory research, and Analytic Hierarchy Process (AHP) analysis, thereby substantiating theoretical constructs through empirical investigation. The study proposes that cross-cultural costume design, undertaken with the purpose of cross-cultural communication, can be conceptualized as a cyclical process involving multiple encoding and decoding iterations. The research elaborates on how costume, functioning as a non-verbal language, serve as a medium for facilitating cross-cultural interactions. Furthermore, the design extraction of cultural symbols is approached through a four-tiered framework. By articulating its research perspective, methodologies, and design cases, this study contributes valuable insights to researchers and practitioners engaged in cross-cultural design and related fields.

Simultaneous precipitation removal of fluoride ion and chloride ion from smelting waste acid using renewable remover

Purification and reuse is a potential method of smelting waste acid disposal. High concentrations of fluoride and chloride in waste acid are harmful impurity and must be removed. Previous studies have shown that fluoride removal with rare earth and chloride removal with bismuth have similar cyclic process of "precipitation removal-agent regeneration" and similar reaction conditions. In this paper, a method of simultaneous precipitation removal of F− and Cl− from waste acid using La(OH)3 and Bi2O3 as a mixed remover was proposed, and the mixed remover is regenerated by sodium hydroxide solution for the recycling of the remover. Thermodynamic analysis of La3+-Bi3+-F−-Cl−-H2O system verified the feasibility of simultaneous removal. The experimental results showed that under the optimum reaction conditions, the removal efficiencies of F− and Cl− were 93.67 % and 96.47 %, respectively, and the concentrations of F− and Cl− in the solution after removal were 66.70 mg/L and 71.10 mg/L, respectively. Under the optimum conditions, the regeneration efficiencies of La(OH)3 and Bi2O3 were 96.80 % and 96.95 %, respectively. The proposed process has the advantages of no waste output, short process, and low energy consumption and provides an environmentally friendly method of removing fluoride and chloride from waste acid.

In-situ cryogenic X-ray diffraction analysis of Poly(dimethylsiloxane) oil and film

Understanding the phase transitions and crystallographic characteristics of polysiloxane materials poses a significant challenge. To address this issue, a custom cryogenic chamber has been developed and integrated with a laboratory X-ray diffraction apparatus, enabling the execution of in-situ temperature-dependent X-ray diffraction (XRD) analyses across the cooling and heating cycles. Through the utilization of diverse sample holders, the real-time monitoring of crystallization and melting phenomena in both linear poly(dimethylsiloxane) (PDMS) oil and crosslinked PDMS film has been made feasible. Notably, high-quality X-ray diffraction data, encompassing 13 diffraction lines, are successfully acquired for the first time for linear PDMS oil at 153K. Subsequent crystallographic examination has revealed a tetragonal unit cell characterized by lattice parameters a = b = 8.3379 Å, c = 11.9284 Å, and space group I 41, suggesting the adoption of a fourfold helical conformation by two polymer chains, each comprising four monomer units, within the lattice structure. This improved and versatile X-ray instrumentation presents clear advantages over conventional commercial powder X-ray diffractometers, which is anticipated to provide a promising in-situ characterization approach for investigating the low-temperature behaviors of liquid or oil materials.

Simulation of indoor space thermal energy circulation in architectural environment design detail features based on visual object tracking algorithm

The heat circulation of interior space plays a crucial role in the design of the built environment, affecting energy efficiency and residential comfort. With the development of science and technology, visual target tracking algorithm provides a new possibility for optimizing thermal energy cycle. The purpose of this paper is to study the simulation method of indoor space thermal energy cycle based on visual target tracking algorithm to improve the efficiency of thermal energy management in building environment design and ensure indoor comfort. The research uses laboratory Settings, combined with high-performance cameras and advanced visual target tracking algorithms, to monitor indoor heat source distribution and personnel movement in real time. Through data acquisition and analysis, the indoor heat cycle model was constructed and simulated by computational fluid dynamics (CFD) software to evaluate the influence of different design parameters on the heat cycle. Through the optimization of the design scheme, the efficiency of indoor heat use is significantly improved, and the comfort score of residents is significantly improved. Therefore, the simulation of indoor space thermal energy cycle based on visual target tracking algorithm provides an effective tool for building environment design, which can realize efficient energy management and improve living comfort.