Middle Stage Research Articles

Comparative transcriptomic insights into key genes for biomass production and lipid synthesis in Chlorella sorokiniana mutated by argon and air atmospheric and room temperature plasma at different culture stages: Common mechanisms and unique differences

Metabolic mechanisms driving rapid lipid production in atmospheric and room temperature plasma-mutagenized Chlorella sorokiniana remain unclear, hindering improvement in lipid productivity through genetic modification. This study investigated two dominant strains, ArX13 and AirX12, mutated by argon and air ARTP, for growth, lipid production, and transcriptomic changes across various culture stages. Results showed that biomass and lipid contents peaked in the late stage, with ArX13 and AirX12 achieving final biomass of 0.71 g/L and 0.70 g/L, and lipid content of 58.57 % glipid gbiomass−1 and 46.90 % glipid gbiomass−1, 2.20 and 1.77 times higher than the control, respectively. The maximum biomass and lipid productivity occurred at the mid-stage, with ArX13 and AirX12 showing biomass productivity of 0.025 gbiomass L−1 day−1 and 0.024 gbiomass L−1 day−1, and lipid productivity of 17.79 mglipid L−1 day−1 and 11.40 mglipid L−1 day−1, respectively. Transcriptomic analysis revealed minimal changes of gene expression during early and late stages, but significant biomass and lipid synthesis during the middle stage. Key genes like PDHB, ATP6A, LSC1 and OGDH were identified in the PPI network throughout the culture cycle, with PDHB remarkably promoting lipid precursor production, up-regulated 8.37 and 4.99-fold in M_ArX13-M_X0 and M_AirX12-M_X0, respectively. In addition, high expression of photosynthesis-related genes (psaL, psaO, psaD, psaK, psbP) contributed the superior lipid production for the argon-based ARTP case, highlighting common and intrinsic mechanisms regulating microalgal lipid accumulation under different ARTP mutations. This study shows that the selection of appropriate ARTP gases can maximize the lipid production of microalgal, and the discovery of some key genes can provide a theoretical basis for the selection of target genes for microalgal research, which is of great significance for promoting the research and development of microalgal lipid engineering.

Reducing costs or increasing efficiency? Unveiling the effects and mechanisms of the digital economy on sustained green innovation

This study examines the impact of the digital economy on sustainable green innovation in China, with a focus on the mediating roles of debt financing costs and resource allocation efficiency. Leveraging a comprehensive dataset of 24,741 firm-year observations from 2008 to 2022, we utilize fixed-effects regression models to analyze the relationships between the digital economy, debt financing costs, resource allocation efficiency, and sustainable green innovation. The results demonstrate that the digital economy positively influences sustainable green innovation, with this effect being partially mediated by reductions in debt financing costs and improvements in resource allocation efficiency. Specifically, the digital economy lowers financing costs and optimizes resource allocation, which collectively enhances green innovation sustainability. The findings remain consistent across various endogeneity and robustness checks, including instrumental variable approach, lagged effects, heckman two-stage method, sample adjustments, alternative measures, and model specifications. Additionally, heterogeneity tests reveal that the digital economy's positive effect is stronger for firms in the early and middle stages of their life cycle and for those operating in less-polluting industries. These insights contribute to the growing literature on digital technologies and sustainable development, offering valuable implications for managers and policymakers aiming to harness the digital economy for advancing sustainable green innovation.

Effects of Combined Nitrogen-Phosphorus on Biomass Accumulation, Allocation, and Allometric Growth Relationships in Pinus yunnanensis Seedlings after Top Pruning.

Pinus yunnanensis (Franch), a species endemic to southwestern China, provides significant ecological and economic benefits. The quality of afforestation can be enhanced by promoting high-quality sprout growth. This study analyzed the effects of six fertilization treatments following top pruning: T1 (N: 0 g/plant-1; P: 0 g/plant-1), T2 (N: 0 g/plant-1; P: 2 g/plant-1), T3 (N: 0 g/plant-1; P: 4 g/plant-1), T4 (N: 0.6 g/plant-1; P: 0 g/plant-1), T5 (N: 0.6 g/plant-1; P: 2 g/plant-1), and T6 (N: 0.6 g/plant-1; P: 4 g/plant-1). The accumulation and allocation of aboveground biomass in roots, stems, and leaves of P. yunnanensis were measured, as well as changes in biomass per plant at 90 days (early stage), 180 days (middle stage), and 270 days (late stage) post-fertilization. At 90 days, root biomass accumulation in T3 was significantly higher, by 13.31%, compared to that in T1 (p < 0.05). The growth rates of stem and plant biomass followed the order T6 > T1 > T3 > T5 > T4 > T2. The biomass of sprouts and individual plants exhibited allometric growth under T1, T5, and T6 treatments. At 180 days, needle biomass allocation in T1 and T4 increased by 7.47% and 8.6%, respectively, compared to 90 days. Combined nitrogen-phosphorus fertilization significantly influenced aboveground biomass allocation, promoting growth more effectively than other treatments. By 270 days, the stem and individual biomass in T2 and T3 treatments showed significant differences (p < 0.01) compared to other treatments. Overall, root, stem, and sprouts were primarily influenced by phosphorus fertilization, while nitrogen fertilization notably promoted needle and leaf growth in later stages. The aboveground components were more affected by phosphorus fertilization. The combination of nitrogen and phosphorus fertilizers enhanced early-stage stem and sprouts, as well as late-stage root development.

Air Injection into Condensate Reservoirs in the Middle and Late Stages Increases Recovery with Thermal Miscible Mechanism

Summary Condensate gas reservoirs in the middle and late stages of development are faced with problems such as formation pressure reduction, serious retrograde condensation, and oil and gas seepage channel plugging, which make it difficult to further improve oil and gas recovery by conventional development methods. For this kind of condensate gas reservoir, in this paper we put forward air injection technology as a development means, taking the K condensate gas reservoir in the Tarim Oilfield as the research object. We explored the thermal oxidation characteristics and displacement efficiency of condensate oil/volatile oil by air injection through the thermal oxidation displacement experiment. In addition, we determined quantitatively the minimum miscibility pressure (MMP) of oil samples at high temperature and the correlation between MMP and temperature through a high-temperature, high-pressure slimtube experiment, and clarified the mechanism of “thermally assisted miscible” through fine full-component numerical simulations under high-temperature and high-pressure conditions, which indoor experiments could not achieve. The results showed that condensate oil/volatile oil can form a stable thermal front by injecting air, and the oil displacement efficiency is more than 90%. The MMP of flue gas produced by condensate oil and oxidation reaction decreases gradually with temperature increase, and the MMP is only 11 MPa at 260°C. The high temperature formed by oxidation heat release forces the oil phase into the gas phase, and the extraction of flue gas makes C2-C4 in the oil phase increase continuously, both of which promote the realization of heat-assisted evaporation miscible phase. This thermal-assisted miscible-phase mechanism makes air injection displacement technology an innovative replacement technology for greatly improving the recovery efficiency of condensate gas reservoirs in the middle and late development stages.

Kinetic analysis and calculation correction methods for moisture evaporation rate in pine lignocellulosic biomass

This study investigates the kinetics of moisture evaporation in pine wood during the drying stage, focusing on analyzing thermogravimetric (TG) curves. The research is based on the kinetic rate model and TG curves obtained at various heating rates, specifically 5, 10, 15, and 20 K/min for the heat release rate, within a temperature range from room temperature to 473 K. Utilizing thermogravimetric experiments and the kinetic rate model, the apparent activation energy and pre-exponential factor are calculated. Further refinement of these calculations is achieved using the Nelder-Mead algorithm. The results show good agreement between the average values of the apparent activation energy (37.88 kJ/mol) and pre-exponential factor (4458.20 s−1) and experimental measurements in the initial and later drying stages, with discrepancies noted in the middle stage. Establishing a relationship between the correction coefficients of these parameters and the heating rate leads to a reduction in calculation errors. Notably, the pre-exponential factor is found to be influenced by heating rates, while the apparent activation energy remains relatively stable. Moreover, the errors are significantly reduced after correction, and the error curve of 10 K/min is the most significant. Overall, the proposed correction method holds promise for accurately calculating moisture evaporation rates in lignocellulosic biomass, offering valuable insights for biomass drying applications.

Facies architecture, pedogenesis and palynology of the Olenekian dryland setting – A sedimentary record of Early Triassic climate oscillations in the SE Germanic Basin

The Early Triassic period was characterised by significant climatic perturbations driven by generally high global temperatures. Several significant shifts in the stable carbon and oxygen isotopes were recognised in the marine settings in the Olenekian age deposits that were linked to short-lasting but relatively high-amplitude climatic events. The record of these events in the continental strata is far less understood due to the stratigraphic incompleteness of such deposits. However, in the Holy Cross Mountains (Poland), the Olenekian continental deposits are well preserved, and sedimentation was relatively continuous, making them an ideal candidate for studying the effects of climate changes and their preservation in continental settings. As such, sedimentological analysis of five wells and one outcrop (over 530 m logged in total), integrated with new and legacy palynological data, allowed the reconstruction and dating of major steps in the palaeoenvironmental evolution of the SE part of the Central European (Germanic Basin), and its comparison with the marine-based climatic models for the Early Triassic. The lower and middle Olenekian stage is represented by fine-grained deposits of dry floodplain interbedded with sandstones deposited within fluvial distributary channels and terminal splays. The palaeosols are mainly represented by aridisols (calcisols), indicating a relatively dry, though not extreme, climate as some water was necessary to support relict plant cover. Towards the mid-Spathian times, the climate became more humid - lacustrine deposits appeared, and palaeosols displayed features of an elevated water table (gleyed vertisols and inceptisols). Frequent storms and floods also affected the lacustrine sedimentation, reflecting volatile climatic conditions. In the late Spathian time, continental sedimentation continued, and the dominance of vertisols and more stacked fluvial channels in the sequence is linked with an increased seasonality, with more pronounced humid seasons. The continental setting lasted until the latest Spathian time, when a marine transgression occurred, marking a new phase in the basin development.

Impact of salivary flow inhibition on masticatory behaviours in healthy individuals.

It remains unclear how the salivary flow and the fat content of food affect bolus formation during mastication. We aimed to clarify: (1) how hyposalivation affects jaw-closing and hyoid-elevating muscle activities in bolus formation, and (2) if the effect of hyposalivation on muscle activity depends on the fat content of food. Eighteen healthy male volunteers were instructed to freely ingest four test foods: Plain, Fat without seasoning, Fat with seasoning, and Soft rice crackers. Masseter and suprahyoid electromyographic activities were recorded before and 30 min after the administration of atropine sulfate, a muscarinic receptor antagonist that induces hyposalivation. Hyposalivation extended the masticatory duration significantly in all the test foods except Fat with seasoning. Masticatory cycle time was significantly longer with vs without hyposalivation for the Soft (p = .011). Suprahyoid activity/cycle was significantly greater with vs without hyposalivation (p = .013). Masticatory cycle time was significantly longer at the late stage with vs without hyposalivation for the Soft (p < .001). Suprahyoid activity/cycle was significantly greater at the middle (p = .045) and late stages (p = .002) with vs without hyposalivation for the Soft and greater at the late stage with vs without hyposalivation for the Plain (p = .043). Changes in masticatory cycle time and suprahyoid activity/cycle for these foods had significantly positive relationship (p < .001). Hyposalivation-induced changes in masticatory behaviours resulted from the middle and late stage suprahyoid activity. Fat content and seasoning compensate for salivary flow inhibition.

Episodic fluid charging and mixing triggers calcite-bearing agates in the Permian Emeishan Basalt, SW China

ABSTRACT Agate, a distinctive form of banded chalcedony, derives its characteristic appearance from the deposition of silica and the presence of impurities. A significant variety of agate-bearing calcite was identified in the Permian Emeishan Basalt located in the southwestern Sichuan Basin. This calcite-bearing agate provides valuable insights into the complex interplay and evolution of fluids and minerals. This study aims to provide a detailed description and analysis of the microscopic textural and geochemical characteristics of the agate, while elucidating the sequence of mineral deposition, fluid properties, and the genetic mechanism underlying its formation. The findings reveal that the agate primarily consists of lamellar calcite and banded chalcedony, exhibiting a variety of textures, thicknesses, and colours. Through the analysis of the transformation and precipitation of epidote and allanite, and the identification of four types of calcites and five micro-silica textures, it has been confirmed that the early stage of fluid in geodes involved the mixing of meteoric water with post-magmatic hydrothermal fluid. The middle and late stages involve the mixing of magmatic-hydrothermal fluid with organic-acid fluid. The charging of silica-rich hydrothermal fluids and the generation of hydrocarbons from organic matter cause fluctuations in SiO2 concentration, pH, and crystallization rates, contributing to the diversity of silica minerals, such as chalcedony and quartz. The interlayered growth observed between chalcedony and calcite is attributed to secondary metasomatism, which occurs after the dehydration and transformation of chalcedony due to increasing temperatures. Notably, the internal texture of the agate is somewhat influenced by pressure variations caused by the episodic charging of the fluid.

Research on moisture absorption characterization of wound composites based on surface concentration modified model

Abstract Four groups of hygroscopic experiments of T700/epoxy composite wound rings at temperatures and humidities of 45°C/60%, 45°C/90%, 70°C/60%, and 70°C/90% were completed in order to study the moisture absorption characterization. Surface concentration correction models characterized by different types of functions such as linear, quadratic, sinusoidal, exponential, and others were proposed to establish a “three-stage” moisture absorption model, in which the initial stage was smooth, the middle stage grew rapidly, and the later stage tended to equilibrium. The theoretically predicted hygroscopic curves derived from quadratic and exponential functions were in good agreement with the experimental data, which revealed the difference in the moisture absorption characterization between the wound rings with high fiber volume and that of the laminates and fabrics and provided a basis for the prediction of the mechanical degradation and life of the wound composites in hygrothermal environments.

Characterization of Male Flower Induction by Silver Thiosulfate Foliar Spray in Female Cannabis at the Middle Reproductive Stage for Breeding.

Cannabis (Cannabis sativa) is a versatile crop belonging to the Cannabaceae family, and is dioecious, typically with separate male and female plants. The flowers of female plants, especially the trichomes, accumulate relatively higher contents of cannabinoids compared with those of male plants. For this reason, to obtain seeds that are genetically female, it is desirable to induce the development of male flowers on a female plant that produces genetically female haploid gametes. Silver thiosulfate (STS) is a highly effective chemical for male flower induction. We investigated male flower induction in three commercial cultivars of female cannabis (Spectrum303, SuperwomanS1, and CBGambit) regarding the treatment frequency, stage of application, and concentration of STS applied as a foliar spray. All three cultivars showed adequate induction of male flowers in response to 1.5 mM STS applied at the early reproductive stage. In particular, SuperwomanS1 was most highly responsive to induction of male flowers, even when treated with 0.3 mM STS at the early reproductive stage. Treatment with three applications of STS was more effective compared with a single application, but a single application of 1.5 mM STS at the early reproductive stage was sufficient for male flower induction. A single STS application during the middle stage of reproductive growth was inadequate for induction of male flowers. However, 6 weeks after three applications of STS, CBGambit exhibited approximately 54% male flower induction at 0.3 mM STS, Spectrum303 showed approximately 56% induction at 3 mM STS, and SuperwomanS1 yielded approximately 26% induction at 1.5 mM (expressed as percentage of total number of individuals with the induced male flowers). Pollen stainability tests using KI-I2 solution and Alexander's staining showed high pollen viability with over 65% at different single STS concentrations, indicating that pollen grains induced by STS have sufficient viability for the self-pollination. This study demonstrated that different cultivars of cannabis respond diversely to different STS concentrations and highlighted the potential benefits of three STS applications during the middle reproductive stage for cannabis breeding.

Direct and indirect effects of urbanization on vegetation: A survey of Yunnan central urban Economic Circle, China

Urbanization affects vegetation distribution by changing land cover. However, it also significantly changes urban water and heat conditions, affecting vegetation growth and development. Vegetation coverage is an effective indicator of vegetation growth. This study analyzed trends in vegetation coverage over the past 35 years, taking the Yunnan Central Urban Economic Circle as the study area. The study was based on applying the pixel dichotomy model and correlation statistical analysis on joint Landsat 5, 7, and 8 long- term remote sensing data, meteorological, and land use data. The direct and indirect effects of urbanization on vegetation coverage were also further explored by constructing an urbanization impact framework. The results revealed that: (1) The urban area during urbanization from 1986 to 2021 increased by 720.29 km2. There was a continuous decline in vegetation cover in and around urban areas, which intensified with accelerating urbanization, with the effect being more pronounced in suburban areas. (2) There were consistent increasing trends in urbanization’s direct and indirect effects on vegetation over the last 35 years, with average negative and positive effects of − 0.41 and 1.59, respectively. (3) Direct effects could mainly be attributed to the expansion of impervious surfaces, whereas the main indirect effect during the late urbanization period (2011–2020) was increasing average temperature. The average temperature showed a correlation coefficient with urbanization of 0.7767, and this relationship showed seasonal heterogeneity due to the significant growth of urban vegetation in summer and winter. (4) Cities that developed faster showed better environmental planning and construction. The direct and indirect effects of urbanization on vegetation during the early and middle stages were higher in cities developing at slow and moderate rates, with this trend reversing only in the later stages of urbanization. The results of this study can increase understanding of the effect of urbanization on vegetation coverage in the Yunnan Central Urban Economic Circle. They can assist in improving urban green spaces and urban ecological resilience.

A multi-objective dynamical artificial bee colony for energy-efficient fuzzy hybrid flow shop scheduling with batch processing machines

Energy-efficient hybrid flow shop scheduling problem (EHFSP) with batch processing machines (BPMs) is rarely considered, let alone EHFSP with BPMs and uncertainty. In this study, an energy-efficient fuzzy hybrid flow shop scheduling problem (EFHFSP) with BPMs at a middle stage and no precedence between some stages is solved, and a multi-objective dynamical artificial bee colony algorithm (MODABC) is presented to simultaneously minimize fuzzy makespan and total fuzzy energy consumption. To produce high quality solutions, a swarm decision is used to dynamically determine the employed bee swarm and onlooker bee swarm, a dynamical employed bee phase is implemented, and an onlooker bee phase with adaptive communication is given. The diversity reinforcement strategy and an adaptive scout phase are also adopted. Extensive experiments are conducted, and the optimal combination of key parameters for the proposed algorithm is determined by the Taguchi method. The computational results demonstrate that the new strategies of MODABC are effective, and MODABC is very competitive in solving the considered EFHFSP.

Die Stellenbosche Heyns: Nagedink oor die vroeë, middel en latere jare van ’n akademiese loopbaan

This contribution is structured in the genre of an academic letter to a deceased colleague, in this case Prof. Johan Adam Heyns (1928–1994). He was appointed for a short period from 1966 to 1970 as a senior lecturer at the Faculty of Theology at Stellenbosch University. This contribution offers a reappraisal of this period in the academic career of Prof. Heyns. His main focus at the time, in line with his teaching duties, was on apologetics and, to some extent, also ethics. The author engages with Prof. Heyns’s views at the time and offers a sixfold mirror to position this phase of his career, namely in terms of the tensions between orthodoxy and modernity, between the philosophical influence of Henk Stoker and the theological influence of Herman Bavinck, and between the implementation of apartheid and the struggle against that. This mirror is held up in order to reflect on the early, middle and later stages of any academic career including that of the author, to contrast the radiance and risk of youthful academic rigour and the wisdom but also the rigidity that may come with mature age.Intradisciplinary and/or interdisciplinary implications: The research done, is not of an interdisciplinary nature. This article contributes to a growing corpus of literature assessing the legacy of Prof. Johan Adam Heyns.

Tectonic-climate-wildfire coupling during the Miocene in the northeastern Qinghai-Tibetan Plateau

The uplift of the Qinghai-Tibetan Plateau (QTP) is one of the most significant geological events in the Cenozoic era. While most studies have focused on the latitudinal differences in the uplift process of the QTP, there has been scant attention to its longitudinal differentiation. The Miocene epoch is pivotal for understanding both the uplift of the QTP and associated climatic changes. Wildfire events not only record changes in vegetation composition but also reflect climatic fluctuations and their driving forces. However, investigations into the interactions among these factors remain limited. This study aims to explore the coupling between the uplift of the QTP, climatic changes and wildfire frequency (or intensity) from northeastern QTP by analyzing microcharcoal concentrations and length-to-width ratios from the Miocene Youshashan Formation in Wulan County, Qinghai Province. The results indicate that the development of wildfires could be divided into three stages. Compared with the intervals 18–15 Ma and 11–8.7 Ma, the middle stage (15–11 Ma) experienced the highest wildfire frequency. This finding underscores the synchronous and close relationship between wildfire occurrences, the uplift of the QTP, and consequent climatic fluctuations. The ratio of length-to-width of microcharcoal indicates that Miocene wildfires in the Wulan Basin primarily occurred at the transitional zones between forests and grasslands. Moreover, the highest peak of wildfire events at six sites gradually shifted from the northeastern to the northwestern QTP from 18–8.7 Ma. This fact demonstrates spatiotemporal disparities in wildfire events from northern QTP, likely stemming from asynchronous uplifts there.

Diagenesis and reservoir quality evolution of estuarine sandstones: Insights from the Cenomanian-Turonian Yolde Formation, northern Benue Trough, NE Nigeria

Estuarine sandstones often exhibit complex diagenetic pathways due to the interaction of fluvial and shallow marine processes, resulting in significant reservoir heterogeneities. The Yolde Formation is an important petroleum reservoir in the Northern Benue Trough, NE Nigeria. However, diagenetic and reservoir quality evolution of the formation are still poorly understood. This study utilizes thin-section petrography, XRD, SEM, and fluid inclusion microthermometry to analyse the composition, diagenesis, and reservoir quality of the sandstones. Results show that the sandstones are mainly arkose and subarkose in composition; they are generally well-sorted and vary in grain size from very fine-to coarse-grained. Three diagenetic stages are identified: early, middle, and late. The early stage includes feldspar dissolution, formation of kaolinite, development of clay coating, and mechanical compaction. The middle stage comprises the formation of authigenic chlorite and Fe-oxide cements. The late-stage diagenesis involves illitization of kaolinite, formation of dickite, albitization of K-feldspar, and precipitation of quartz overgrowths. The diagenetic evolution of the sandstones was strongly controlled by their compositional makeup. The feldspathic nature of the sandstones resulted in the formation of kaolinite, illite, and quartz overgrowths, through feldspar dissolution and silica supply. The inner and middle estuarine facies have inhibited the development of quartz overgrowths due to well-developed clay coatings, whereas the outer estuarine facies were well-cemented by quartz overgrowths due to lack of clay coatings. Illitic clay coatings were found to be effective in preventing quartz cementation. Fluid inclusion analysis reveals that the formation temperatures of the quartz overgrowths range from 98 °C to 135.5 °C, corresponding to burial depths ranging between 2.3 and 3.5 km. These findings would provide useful insights that would reduce the risks of exploration of the sandstones and also supplies potential input data for forward diagenetic modelling of their subsurface equivalents in similar depositional settings elsewhere.

Quantitative evaluation of the sealing effect of penetrating gas drilling and in situ repairing technology for smooth holes

AbstractIn this study, a new method is proposed to quantitatively determine the extraction of boreholes under the effect of time. The main purpose of this method is to divide the gas drilling holes in the monitoring time into two stages: the early stage of extraction and the middle stage of extraction. The early stage of extraction uses the gas pressure difference to detect the gas tightness of the drilling holes and determine the type of gas leakage of the drilling holes. Moreover, the unqualified drilling holes are repaired immediately to ensure that all the drilling holes in the middle stage of the monitoring are the qualified holes at the early stage of the inspection. In the middle of extraction, the average attenuation rate of the fitting attenuation curve of pure gas extraction in the extraction borehole is calculated by monitoring, the growth rate of the linear fitting of the pure air leakage is calculated, and their ratios are used as the basis for judging the repair value of the gas leak borehole and the gas leak borehole. This quantitative evaluation method is used to monitor the extraction effect of four test holes in a field test conducted at Ping Coal Mine 10. The results indicate that, after adopting in situ downhole repair technology in the early stage of extraction, the average air leakage of Borehole No. 4, which failed due to air leakage in the borehole, decreased from 9.33 to 1.26 L/min (a reduction of 86.5%). Similarly, that of Borehole No. 3, which failed due to penetration of fissures in the surrounding rock, had an air leakage drop from 8.35 to 1.34 L/min (a reduction of 84.0%). These improvements demonstrate the remarkable effectiveness of the method. The quantitative evaluation method established in this study is not only simple to operate but also stable and reliable. Thus, it is feasible to be applied in the field, which provides important technical support for the improvement in gas extraction effect during coal mine safety production.

Effect of Extrusion Ratio on Mechanical Behavior and Microstructure Evolution of 7003 Aluminum Alloy at High-Speed Impact.

The extrusion ratio (ER) is one of the most important factors affecting the service performance of aluminum profiles. In this study, the influence of ER on the mechanical behavior and microstructure evolution of 7003 aluminum alloy at high-speed impact with strain rates ranging from 700 s-1 to 1100 s-1 was investigated. The studied alloy with an ER of 56 formed coarse grain rings during the heat treatment. The microstructure of the alloys with ERs of 20 and 9 is relatively uniform. The results indicate that under high-speed impact, the mechanical response behavior of the 7003-T6 alloy with different ERs is different. For the alloy with an ER of 56, strain hardening is the main mechanism of plastic deformation. In contrast, a flow stress reduction occurs at middle deformation stage for the ones with ERs of 20 and 9 due to concentrated deformation, which is more significant in the alloy with an ER of 20. Under high-speed impact, the alloy with an ER of 56 undergoes uneven plastic deformation due to the presence of coarse grain rings. The deformation is mainly borne by the region of coarse grains near the edge, and the closer to the center, the smaller the deformation. The deformation of the alloys with ERs of 20 and 9 is relatively uniform, but exhibits localized concentrated deformation in the area near the edge. The significant plastic deformation within deformation band causes a local temperature rise, resulting in a slight decrease in flow stress after the peak. These results can provide reliable data support for the application of 7003 aluminum alloy in the vehicle body crash energy absorption structure.

Selection of placement position of support points for early and mid-term mechanical repair of femoral head necrosis

To investigate the clinical efficacy of the placement of the main mechanical support points in the early and middle stages of mechanical repair of femoral head necrosis in preventing collapse of the femoral head. A retrospective analysis was performed for 17 cases 22 hips of non-traumatic femoral head necrosis in the early and middle stages from June 2018 to June 2019, including 14 males 18 hips and 3 females 4 hips, aged 34 to 47 years old. Among them, 6 cases were hormonal, 8 were alcoholic and 3 were idiopathic. According to China-Japan Friendship Hospital(CJFH) classification, 9 hip were type L1, 8 were L2, 5 were L3. All cases were given dead bone scraping, autologous iliac granules pressed bone grafting, and allogeneic fibula column support treatment. After surgery, Sanqi Jiegu Pill() was administered orally for 3 months. X-rays of both hips were performed after surgery and follow-up, and the clinical efficacy was evaluated by hip Harris score before and after surgery. All cases were followed up for 24 to 38 months. The Harris score of 22 hips increased from 58 to 77 preoperative to 68 to 94 at the final follow-up. At the final follow-up, 3 hips were excellent, 11 hips were good, 3 hips were acceptable, 5 hips were poor. Two hips of L2 type progressed to ARCO ⅢB stage and continued to be observed, 2 hips of L2 type and 2 hips of L3 type progressed to ARCO Ⅳ stage, and received total hip replacement, and 1 hip infection at 3 months after surgery was given a cement spacer. Based on CJFH classification, collapse can be predicted to a certain extent according to the area, volume, location and human biological characteristics of osteonecrosis, and the main mechanical support points are found on this basis to prevent collapse.

Federated learning for decentralized fault diagnosis of a sucker-rod pumping system with class imbalance data

The development of modern oilfields has entered the middle and late stages, transforming towards digitalization and intelligence. However, the distribution of the sucker-rod pumping systems is decentralized, and the working condition information is skew-distributed. This situation poses a significant challenge to existing centralized fault diagnosis mechanisms. To address the existing practical challenge in the oilfield, a federated learning-based fault diagnosis framework for class imbalance in decentralized sucker-rod pumping systems (FL-CI) is proposed. This framework incorporates a parameter anonymization-ratio upload mechanism to mitigate the risk of gradient tracking. Then, a monitoring mechanism is leveraged to reversely infer global class-imbalance data using trained parameters uploaded by the clients. In addition, a ratio loss function is designed to calibrate the influence of class imbalance on the global system. After conducting comparative analysis, ablation analysis, and sensitivity analysis on a rod-pumping unit dataset (RPUD), as well as comparative and ablation analyses on the Case Western Reserve University bearing dataset (CWRU), the experimental results demonstrate that the FL-CI framework achieves superior diagnostic performance on the RPUD, with eight out of twelve evaluation metrics significantly outperforming seven state-of-the-art methods. A similar trend is observed on the CWRU, further validating the effectiveness and generalizability of the FL-CI.

Evaluation of sensor-enabled piezoelectric geoelectric cable in cyclic shear tests of subgrade soil under vertical cyclic loads

Of late, deformation of subgrade soil has led to an increasing number of road subsidence diseases. Real-time monitoring of subgrade deformation is critical to ensure the safety of subgrade operations. In this paper, a sensor-enabled piezoelectric geoelectric cable (SPGC) with impedance strain effect and piezoelectric effect is tested. The SPGC impedance and voltage signals obtained by cyclic shear test under vertical static load and cyclic shear test under vertical cyclic load are used to evaluate the monitoring effect. The results showed that normal stress had the greatest effect on the shear strength of the soil, whereas the normal stress and horizontal shear displacement amplitude significantly influenced the strain in the soil. Varying the normal and horizontal shear frequencies had little effect on the shear strength and strain of the soil. The normalized impedance and voltage of the SPGC, respectively, decreased and increased rapidly during the initial stage of the shear cycle; these changes were relatively small during the middle and late stages of the shear cycle. The SPGC voltage waveform revealed the changes in the shear stress and vertical displacement under different normal and horizontal shear frequencies, from which the stability of the subgrade soil under the aforementioned conditions could be evaluated. The variations in the SPGC impedance and effective voltage from the cyclic shear tests under both vertical static and vertical cyclic loads remained essentially consistent with the number of cycles. However, there was a difference in that the trough of the SPGC impedance under the vertical cyclic load was larger than that under the vertical static load; likewise, the effective SPGC voltage under the cyclic load was larger than that under the static load. Through an analysis of the SPGC impedance and voltage signals in the subgrade soil, the consistency of the SPGC-normalized impedance and effective voltage with shear stress was clarified; this helped us evaluate the health of the subgrade and monitor the characteristics of the precursor signals before a slide were to occur, thereby affording us an opportunity to issue timely warnings.