bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact of Patient Age on Management of Hypothyroidism: A Survey of Physicians from Three Developing Regions
Authors: Beshyah Salem A. , Bashir Mohammed , Hafidh Khadija , Afandi Bachar , Shaikh Shehla , Hammami Sonia , Khalil Ali B.
Published: August 2024

Background The thyroid-stimulating hormone (TSH) levels increase with age, and aiming for the same TSH target applicable in a younger population in older patients who are on replacement with thyroid hormones.

Methods We assessed practice patterns regarding TSH goals and explored factors influencing physicians' decision-making when managing hypothyroidism. Multiple-choice questions in a case-based survey of a convenience sample of physicians practicing in relevant disciplines in three developing regions.

Results Of the total 286, senior physicians represented 63% and mid-grades represented 27% of the respondents. Forty-one percent were endocrinologists, 19% were internists with endocrine interests, and 16% were family physicians. Over half (52%) practiced at a tertiary level and 42% had been in practice for over 20 years. Fifty percent of respondents had more than 20% of their patients over 65 years.

Several attributes were factored into decision-making when managing hypothyroidism. Respondents took into account age (75%), preceded by the presence of cardiac arrhythmias (80%), pregnancy (79%), heart disease (78%), and patient symptoms (77%) when determining the treatment strategy. When presented with scenarios differing in patients' age, around 90% of physicians targeted a TSH ≤ 3.0 mIU/L in 30-year-old patients. Fifteen percent of respondents targeted a TSH of 1.6 to 3.0 mIU/L in octogenarians, but 78% targeted a TSH > 3.1 to 5.0 mIU/L in this group. Regardless of sex, physician-reported TSH goal ranges (0.1–0.5, 0.6–1.5, 1.6–3.0, and 3.1–5.0 mIU/L) increased directly to patient age. Overall, respondents were less inclined to start treatment in 85-year-olds than in 70-year-old females with TSH of 6 mU/L (20% vs. 11%). Females with a TSH of 15 mU/L were more likely to get treated than those with a 6 mU/L TSH. Vital persons are more likely to be treated with thyroxine than vulnerable persons for the same TSH levels. Multivariate analysis showed that compared with endocrinologists, family physicians and other specialties were less likely to consider age in their clinical decisions, odds ratio (OR) 0.2 (95% confidence interval [CI] 0.1–0.7), p = 0.018, and OR 0.3 (95% CI 0.1–0.8), p = 0.013, respectively.

Conclusion A consensus is needed on the role of patients' age in hypothyroidism management, the complexity of managing hypothyroidism in an older adult patient, and the variability in practice patterns among physicians. Addressing these challenges demands ongoing dialogue and collaboration among health care providers to improve patient care and outcomes in hypothyroidism management across different age groups.
Experimental investigation of the effects of altitude on the performance of a non-sprayed porous burner
Authors: Gao Huaibin , Li Zhilong , Zong Shouchao , Ma Yu , Zhang Chuanwei
Published: August 2024

A self-sustained burner was built for diesel oil without an atomizer using metal fiber felt as an evaporator. The effects of firing rate, excess air coefficient, and altitude on the temperature distribution, NOx emission, and CO emission were studied. The results indicated that fuel evaporation and combustion inside the burner are significantly influenced by the altitude. The overall temperature distribution inside the burner first decreased and then increased with the increase in altitude. The main reasons for the formation of NOx are the local high temperature during start-up and the high temperature after flame stabilization. The NOx emission initially decreased and then increased with the increase in altitude. The NOx emission is the lowest at an altitude of 1700 m and reaches its maximum value at an altitude of 4780 m. The main cause of CO generation is incomplete combustion during the start-up process. The CO emission decreased with the increase in the excess air coefficient at the same altitude. Less CO is produced with the increase in altitude at the same firing rate and excess air coefficient.
Adaptive spiking, itinerancy, and quantum effects in artificial neuron circuit hardware with niobium–hafnium oxide-niobium memristor devices inserted
Authors: Nayfeh Osama M. , Manukian Haik , Kelly Matthew , Mauger Justin
Published: August 2024

To improve artificial intelligence/autonomous systems and help with treating neurological conditions, there is a requirement for the discovery and design of artificial neuron hardware that mimics the advanced functionality and operation of the neural networks available in biological organisms. We examine experimental artificial neuron circuits that we designed and built in hardware with memristor devices using 4.2 nm of hafnium oxide and niobium metal inserted in the positive and negative feedback of an oscillator. At room temperature, these artificial neurons have adaptive a spiking behavior and hybrid non-chaotic/chaotic modes. When networked, they output with strong itinerancy, and we demonstrate a four-neuron learning network and modulation of signals. The superconducting state at 8.1 K results in Josephson tunneling with signs that the hafnium oxide ionic states are influenced by quantum control effects in accordance with quantum master equation calculations of the expectation values and correlation functions with a calibrated time-dependent Hamiltonian. These results are of importance to continue advancing neuromorphic hardware technologies that integrate memristors and other memory devices for many biological-inspired applications and beyond that can function with adaptive-itinerant spiking and quantum effects in their principles of operation.
Multi-stage planning method for independent energy storage based on dynamic updating of key transmission sections
Authors: Feng Peiru , Wang Jiaqing , Tian Jia , Liu Qing , Yang Hao , Ma Yinghao , Wei Ming
Published: August 2024

A multi-stage planning method for independent energy storage (IES) based on dynamically updating key transmission sections (KTS) is proposed to address issues such as uneven power flow distribution and transmission congestion resulting from the high penetration of renewable energy sources and load growth. First, an IES planning model considering KTS constraints is established by searching and updating the KTS and associated constraints. This model takes into account IES investment and operation costs, maintenance costs, revenue from spot price differences, and penalties for system congestion. Then, a multi-stage planning method for energy storage is proposed based on the dynamic updating of KTS and the annual planning results. To verify the effectiveness and feasibility of the proposed method, a case study simulation is conducted using the improved IEEE 39-bus New England standard system. The results demonstrate the ability of the method to achieve multi-stage rolling optimization of IES, providing a reference for future efforts toward multi-stage planning of IES.
Growth performance and meat quality of finishing pigs fed diets supplemented with antioxidants and organic acids in late summer
Authors: Le Hieu H. , Hewitt Robert , Tritton Sally , D’Souza Darryl Nicholas , Shakeri Majid , Iqbal Yasir , Ha Minh , Warner Robyn D. , Dunshea Frank R. , Cottrell Jeremy J.
Published: August 2024

Context Heat stress compromises growth performance and meat quality and results in economic losses in pork production. Aims We investigated the effects of supranutritional levels of selenium (Se) and vitamin E (VitE), along with organic acid blends, on the growth performance and meat quality of finishing pigs over a period of weeks during late summer to early autumn in Westbrook, Queensland, Australia. Methods A total of 264 crossbred pigs (25.8 ± 2.4 kg, mean ± s.d.) at 11 weeks of age were randomly assigned in a 2 × 2 × 2 factorial design with two aging times (2 or 5 days) nested within each pig. The factors included antioxidants (Se/E, with recommended or supranutritional doses of Se and VitE), an organic acids (OA) blend added to drinking water (control vs supplemented), and sex (female vs male). Key results Between 16 and 18 weeks of age, high Se/E decreased daily feed intake (P = 0.010) but had no effects on average daily gain or feed conversion efficiency (FCE). Male pigs grew faster (P = 0.040) and had a higher FCE than females (P = 0.050). Supplementation with OA increased FCE in males but not females (OA × Sex interaction, P = 0.035). Between Weeks 16 and 20, male pigs grew faster (P < 0.001), tended to eat more (P = 0.057), and had higher FCE (P = 0.002) than females (P < 0.001). There were no main effects of Se/E or OA on meat quality, except protein oxidation was reduced by high Se/E (P = 0.047). Sex impacted only Warner-Bratzler shear force (WBSF), with male pigs having lower WBSF than females (P = 0.053). Meat aging decreased WBSF (P < 0.001), but it increased cooking loss (P = 0.036), myofibrillar fragmentation index (P < 0.001), lipid oxidation (P < 0.001) and colour parameters (P < 0.001 for all). Conclusions Supplementation with Se/E for up to 10 weeks and OA for 5 weeks did not influence production parameters or pork quality in late summer, except that high Se/E decreased protein oxidation, and significant heat stress conditions were not experienced as expected. Implications Supplementation with Se/E and OA may be effective when environmental temperatures are higher.
The role of funding in the performance of Latin America’s protected areas
Authors: Lessmann Janeth , Geldmann Jonas , Fajardo Javier , Marquet Pablo A.
Published: August 2024

Conservationists have long argued that inadequate funding for managing protected areas (PAs) jeopardizes their ability to achieve conservation goals. However, this claim has rarely been substantiated by quantitative evaluations. To address this, we examined the impact of funding on PA effectiveness both at the scale of 17 national PA systems across Latin America and within a PA system (Ecuador), for which we had precise historical financial data. Most PAs reduced deforestation between 2000 and 2010, demonstrating their crucial role in forest conservation. However, large deficits in funding considerably reduced the effectiveness of PAs in Ecuador (on average, a unit decrease in deficit leads to a 3.07% increase in effectiveness in avoiding deforestation). While differences in effectiveness between individual PAs in Ecuador were associated with funding deficits, national-level socioeconomic metrics (e.g., the Human Development Index) were the major factor when comparing PA system-level effectiveness among countries. This result suggests that while funding plays a major role in the performance of individual PAs, the quality of the socioeconomic context at the country level is critical for the overall performance of the PA systems. We, therefore, emphasize that maximizing the effectiveness of PAs requires a multilevel approach that includes better and more strategic resource allocation for individual PAs, combined with actions for strengthening the governance and institutions that regulate PA systems.
Reconstruction of Phanerozoic climate using carbonate clumped isotopes and implications for the oxygen isotopic composition of seawater
Authors: Thiagarajan Nivedita , Lepland Aivo , Ryb Uri , Torsvik Trond H. , Ainsaar Leho , Hints Olle , Eiler John
Published: August 2024

The oxygen isotope ratio
18
O/
16
O (expressed as a δ
18
O
VSMOW
value) in marine sedimentary rocks has increased by ~8‰ from the early Paleozoic to modern times. Interpretation of this trend is hindered by ambiguities in the temperature of formation of the carbonate, the δ
18
O
seawater
, and the effects of postdepositional diagenesis. Carbonate clumped isotope measurements, a temperature proxy, offer constraints on this problem. This thermometer is thermodynamically controlled in cases where carbonate achieves an equilibrium internal distribution of isotopes and is independent of the δ
18
O of the water from which the carbonate grew; therefore, it has a relatively rigorous chemical–physics foundation and can be applied to settings where the δ
18
O of the water is not known. We apply this technique to an exceptionally well-preserved Ordovician carbonate record from the Baltic Basin and present a framework for interpreting clumped isotope results and for reconstructing past δ
18
O
seawater
. We find that the seawater in the Ordovician had lower δ
18
O
seawater
values than previously estimated, highlighting the need to reassess climate records based on oxygen-isotopes, particularly where interpretations are based on assumptions regarding either the δ
18
O
seawater
or the temperature of deposition or diagenesis. We argue that an increase in δ
18
O
seawater
contributed to the long-term rise in the δ
18
O of marine sedimentary rocks since the early Paleozoic. This rise might have been driven by a change in the proportion of high- versus low-temperature water–rock interaction in the earth’s hydrosphere as a whole.
Nucleated synthetic cells with genetically driven intercompartment communication
Authors: Ioannou Ion A. , Monck Carolina , Ceroni Francesca , Brooks Nicholas J. , Kuimova Marina K. , Elani Yuval
Published: August 2024

Eukaryotic cells are characterized by multiple chemically distinct compartments, one of the most notable being the nucleus. Within these compartments, there is a continuous exchange of information, chemicals, and signaling molecules, essential for coordinating and regulating cellular activities. One of the main goals of bottom–up synthetic biology is to enhance the complexity of synthetic cells by establishing functional compartmentalization. There is a need to mimic autonomous signaling between compartments, which in living cells, is often regulated at the genetic level within the nucleus. This advancement is key to unlocking the potential of synthetic cells as cell models and as microdevices in biotechnology. However, a technological bottleneck exists preventing the creation of synthetic cells with a defined nucleus-like compartment capable of genetically programmed intercompartment signaling events. Here, we present an approach for creating synthetic cells with distinct nucleus-like compartments that can encapsulate different biochemical mixtures in discrete compartments. Our system enables in situ protein expression of membrane proteins, enabling autonomous chemical communication between nuclear and cytoplasmic compartments, leading to downstream activation of enzymatic pathways within the cell.
Large-scale genome sequencing of giant pandas improves the understanding of population structure and future conservation initiatives
Authors: Lan Tianming , Yang Shangchen , Li Haimeng , Zhang Yi , Li Rengui , Sahu Sunil Kumar , Deng Wenwen , Liu Boyang , Shi Minhui , Wang Shiqing , Du Hanyu , Huang Xiaoyu , Lu Haorong , Liu Shanlin , Deng Tao , Chen Jin , Wang Qing , Han Lei , Zhou Yajie , Li Qiye , Li Desheng , Kristiansen Karsten , Wan Qiu-Hong , Liu Huan , Fang Sheng-Guo
Published: August 2024

The extinction risk of the giant panda has been demoted from “endangered” to “vulnerable” on the International Union for Conservation of Nature Red List, but its habitat is more fragmented than ever before, resulting in 33 isolated giant panda populations according to the fourth national survey released by the Chinese government. Further comprehensive investigations of the genetic background and in-depth assessments of the conservation status of wild populations are still necessary and urgently needed. Here, we sequenced the genomes of 612 giant pandas with an average depth of ~26× and generated a high-resolution map of genomic variation with more than 20 million variants covering wild individuals from six mountain ranges and captive representatives in China. We identified distinct genetic clusters within the Minshan population by performing a fine-grained genetic structure. The estimation of inbreeding and genetic load associated with historical population dynamics suggested that future conservation efforts should pay special attention to the Qinling and Liangshan populations. Releasing captive individuals with a genetic background similar to the recipient population appears to be an advantageous genetic rescue strategy for recovering the wild giant panda populations, as this approach introduces fewer deleterious mutations into the wild population than mating with differentiated lineages. These findings emphasize the superiority of large-scale population genomics to provide precise guidelines for future conservation of the giant panda.
Spatiotemporal pattern formation in parametrically driven two-dimensional Bose–Einstein condensates
Authors: Wan Jun , Wen Wen , Li Hui-jun
Published: August 2024

We investigate spatiotemporal periodic patterns in harmonically trapped Bose–Einstein condensates (BECs) driven by a periodic modulation of the interaction. Resonant with the breathing mode, we show the emergence of a square lattice pattern containing two orthonormal stripes. We study the time evolutions of the lattice patterns for different driving strengths and dissipations. We find that its spatial periodicity and temporal oscillating frequency match the Bogoliubov dispersion, which is the intrinsic property of the system and relevant to the parametric amplification of elementary excitations. In the circumstances of strong driving strength and low dissipation, we further observe the triad interaction and the resulting superlattice state, which are well explained by the nonlinear amplitude equation for superimposed stripes. These results shed light on unexplored nonlinear spatiotemporal dynamics of two-dimensional patterns in harmonically trapped BECs that can pave the way for engineering exotic patterns by state-of-the-art experiments.
Credible calculation method for regional corrected carbon emission factors taking into account the nearby consumption of renewable energy
Authors: Guo Qinglei , Pan Xiukui , Zhou Weiqing , Li Peng , Li Qi
Published: August 2024

The carbon emission factor of the power grid is a key data indicator for measuring the carbon emission level on the user side. Currently, the carbon emission factor of the power grid is not sufficient to accurately express the regional carbon emission level, and especially cannot accurately reflect the regional new energy consumption level, which affects user confidence in emission reduction and the accuracy of carbon emission quota issuance. Therefore, this article utilizes blockchain technology and carbon emission flow theory to realize the impact of user-side self-generated and self-used photovoltaics (PV) on carbon emission factors. We have constructed a residual power grid correction model, designed a blockchain intelligent terminal module and functional requirements, ensured the correctness of the model and results from the source, solved the problem of data tampering and insufficient data credibility generated by terminal devices at the source, and ultimately helped achieve the dual carbon goal.
Distribution and potential assessment of biomass raw material resources in the Inner Mongolia region
Authors: Ma Qiang , Lv Yue , Chai Rui , Wang Meng , Ren Yucheng
Published: August 2024

With the national energy transition and upgrading, the development of clean energy has attracted significant attention. Among these, agricultural biomass energy plays a crucial role in realizing a low-carbon transition. Taking the Inner Mongolia Autonomous Region as a case study, this research assesses and analyzes the potential of biomass availability in agricultural waste by introducing net biomass calculation. It also examines the overall characteristics of the spatial distribution of available biomass resources in the Inner Mongolia Autonomous Region using GIS software. The results indicate that in 2022, the total amount of straw resources in Inner Mongolia will reach 48, 926, 800, 000 tons, with 24, 198, 900, 000 tons of available biomass energy. Additionally, the dry matter content of livestock and poultry waste is estimated at 28, 198, 000, 000 tons, with 14, 233, 200, 200 tons of available biomass energy. Geospatial analysis reveals a decreasing trend in the regional distribution of available biomass resources from the northeast to the southwest. Furthermore, this paper analyzes various biomass utilization methods. It is estimated that biomass resources can reduce carbon emissions by 913.72 tons if used for biomass power generation. Biomass can also be utilized in pyrolysis and gasification processes. Through these conversion technologies, approximately 2562.62 tons of available biomass in the Inner Mongolia region can be converted. In the benefit analysis, the Inner Mongolia region demonstrates a good economic and environmental situation, with an estimated economic benefit and environmental situation, with an estimated economic benefit of about 70-17 million yuan. Overall, agricultural biomass feedstocks in Inner Mongolia hold significant potential for achieving the dual-carbon goals. Relevant departments should intensify their research and development efforts to promote green agriculture and realize sustainable development.
Low-carbon optimal scheduling of an integrated electricity, heat-and-gas energy system considering a biomass gas and carbon capture power plant
Authors: Gong Lei , Huang Xin , Xiao Maner
Published: August 2024

In light of enhancing the extraction level of biomass energy and rectifying the efficiency of integrated energy system (IES) operations in the backdrop of the “ twin carbon” policy, we present an enhanced scheduling methodology for IES incorporating biomass gas and carbon absorption power plants, addressing the constraints of linear carbon trading. Initially, an organizational blueprint for the combined exploitation of biomass-laden gas, electricity-to-gas, and carbon absorption power plants is established. Secondly, we devise a ladder-like configuration of carbon trading mechanisms to counterbalance the inadequacies of standard persistent carbon trading schemes. Subsequently, this advanced form of carbon trading is incorporated into the IES framework and is optimized using the ultimate goal of minimizing system expenditures. Lastly, evaluations across diverse scenarios demonstrate that the proposed sequential carbon trading significantly enhances the economic viability of the system, and the accompanying simulation corroborates the validity of our proposed model.
Research on energy-saving and carbon-reducing technologies for water-ground source heat pump units
Authors: Wen Xueying , Cai Shengchuan , Dou Jie
Published: August 2024

The heat pump industry’s energy consumption as a percentage of total energy consumption is constantly increasing. Research on energy-saving and carbon-reducing technologies, and manufacturing high-efficiency units of heat pump with water-ground source has become the main trend of the current heat pump industry. With proposal of the national “dual-carbon” strategy goal, enhancing the energy efficiency of units of heat pump with water-ground source has become a key way to transform and upgrade the refrigeration and air conditioning industry. The aim of this study is to combine current studies on energy-saving and carbon-reducing technologies for units of heat pump with water-ground source and applying these technologies. Through experimental tests, the energy efficiency of units of heat pump with water-ground source is more than 15% higher than that of ordinary units.
Narrow linewidth optical feedback vertical cavity surface emitting lasers based on cholesteric liquid crystal
Authors: Zhang Chen , Fu Lishan , Wang Jisheng , Guan Baolu
Published: August 2024

In this paper, we present a narrow linewidth vertical cavity surface emitting laser (VCSEL) based on cholesteric liquid crystal (CLC). We investigated the impact of incorporating optical feedback into the external cavity on the linewidth of VCSELs, and successfully utilized CLC film as the reflector for the external cavity. This enabled us to achieve mode control and linewidth compression in VCSELs through optical feedback. The linewidth of the optically feedbacked VCSEL was measured at different driving currents and oxidation apertures. Under the same oxidation aperture, when the driving current is 1.2 mA, the linewidth is compressed from 120.9 MHz to 55.97 MHz; when the driving current is 0.8 mA, the linewidth is compressed from 22.87 MHz to 12.68 MHz. When the driving current remains constant, the linewidth is compressed from 169.31 MHz to 72 MHz when the oxidation aperture is 7 μm; and from 39.13 MHz to 10 MHz, when the oxidation aperture is 3 μm. By validating the feasibility of employing CLC film as an external cavity reflector mirror, our findings offer new insights towards achieving narrow-linewidth external cavity systems, thereby laying an experimental foundation for subsequent high-quality and highly integrated LC optical feedback VCSELs.
All-solid-state flexible micro-supercapacitors with enhanced electrochemical performance obtained by hybridizing mxene with butterfly graphite
Authors: Luo Hao , Li Yong , Liu Wenjun , Qian Tu
Published: August 2024

All-solid-state flexible micro-supercapacitors (MSCs) have the advantages of large energy storage capacity, small size, and good flexibility, which can be used as micro power sources. A 2D titanium carbide (MXene) has metallic conductivity, good hydrophility, and excellent processing properties, showing its great potential in flexible MSCs. However, the self-packing of MXene sheets hinders charge transfer and ion transport, limiting its electrochemical capacity. Herein, MSCs were prepared from a composite material of butterfly-like graphite (BTG) and MXene. BTG was inserted into the MXene layer to prevent its overs tacking, which promotes the diffusion of electrolytes and improves the electrochemical capacity of MSCs. As a result, MXene/BTG MSCs exhibit a large capacitance of 177.9 mF cm−2 at 5 mV s−1. In addition, the specific capacitance retention of MXene/BTG-30% MSCs can reach 80.4% in 0.1 -1 mA cm−2.
Multi-objective optimization of the configuration of Electric vehicle charging piles based on scenario analysis
Authors: Li Yanbin , Li Zhihua , Cao Defa , Wei Cunliang , Yu Min
Published: August 2024

The optimization of electric vehicles (EVs) charging piles configurations is explored across varying demand levels, land prices, and unit time cost, with the aim of minimizing users’ waiting times and construction operation and maintenance costs. The analysis indicates that a significant reduction in user waiting times can be achieved through the increase of charging piles, with only a marginal rise in construction operation and maintenance cost, proving to be economically beneficial, especially in scenarios of high user time cost. After determining the minimum number of charging piles according to the charging demand, adding 1 to 4 charging piles based on it is the most direct and convenient method to determine the configuration of charging piles.
Development of a DSP based collaborative computing platform for power system
Authors: Chen Julong , Huang Guanbiao , Yang Jierui , Zhao Ligang , Li Zhen , Wang Changxiang , Zhang Zhaofeng , Zhen Hongyue , Wu Xiaoshan
Published: August 2024

With the advancement of information technology, there has been tremendous progress in data production, processing, and storage technology, especially in data processing technology. With the rapid development of the power grid, its operation has become more intelligent and efficient. Traditional power system simulation and analysis tools have disadvantages, such as slow message transmission and the inability to share data, which cannot meet the requirements of modern power system simulation calculations. DSP was introduced and developed by the Southern Power Grid Research Institute and can perform various simulation calculations such as transient stability calculation, power flow calculation, and short circuit calculation. It is widely used in departments such as power planning and design. However, the data calculated by DSP is input through a data card, which is cumbersome and difficult to manage. In order to meet the new requirements of power system simulation analysis, a power system collaborative computing platform has been developed based on DSP, which makes DSP data maintenance and management more efficient and intuitive. It comprehensively improves the efficiency of power grid planning work. This article provides a detailed analysis of the architecture design and application problems of the power system collaborative computing platform, clarifies the requirements of large-scale interconnected power grids for simulation computing data management, and proposes solutions that can meet the needs of simulation computing data management in China’s power grid from two aspects: key data architecture issues and software architecture technology.
Analysis of influencing factors and its coupling degree of resistivity of rocks
Authors: Wang Zhinan , Wang Jianguo , Wei Shengyun , Hu Jian , Li Yan
Published: August 2024

Over the years, it has been carried out on the method of resistivity exploration mainly from the macro level, and it has made a greater contribution to the search for minerals. However, it is found that the data interpretation effect obtained from the macro level for ore deposit exploration has a large error. Therefore, the research on the method of resistivity exploration of rock and ore from the micro level has become a new research difficulty and hot spot. Based on the team’s previous experimental analysis and research, this paper takes the Chazangcuo Cu-Pb-Zn deposit as the research object, carries out the study of the resistivity of rocks from the microscopic level, and focuses on the study of water content, temperature, pressure, porosity and other influencing factors of the Chazangcou deposit, with the help of field geological survey, testing, and analysis. The coupling process of the influencing factors is analyzed based on the experimental results and the grey correlation idea, and the calculation of the coupling degree is proposed to indicate the degree of coupling. According to the results of the test and calculation, the coupling degree of resistivity of rocks is water content>porosity>temperature>pressure.
Development and properties research of different structural EPEG-type polycarboxylate superplasticizers in UHPC
Authors: Wang Zhaopeng , Fang Yunhui , Zhong Lina
Published: August 2024

Ethylene glycol monovinyl ether polyethylene glycol ether (EPEG) is employed as a novel 6C monomer to synthesize polycarboxylate superplasticizers of varying molecular weights through free radical polymerization. Gel permeation chromatography (GPC), rheological analysis, and other testing methods are employed to investigate the influence of EPEG-based polycarboxylate superplasticizers on the dispersibility, rheological properties, and workability of Ultra-High Performance Concrete (UHPC). The results indicate that with increasing monomer molecular weight, the fluidity and rheological parameters (plastic viscosity and yield stress) of the samples tend to increase, accompanied by a similar trend in slump flow diameter and an increase in the slump flow diameter and 28-day compressive strength of the UHPC mix. When the monomer molecular weight reaches 1100, corresponding to E1PCE, the dispersibility, flowability, and mechanical properties of the UHPC mix are optimized.
Study on hydrogen embrittlement sensitivity of 30CrMnSiNi2A steel in electrochemical hydrogen charging
Authors: Cen Chengxian , Zhu Junjin , Li Ronghui , Wu Qingyuan
Published: August 2024

Electrochemical hydrogen charging was performed on a 30CrMnSiNi2A steel tensile sample, and the difference in hydrogen-charging effect with different hydrogen-charging times, current densities, and toxic agents was compared. The effect of hydrogen on the tensile strength, elongation and failure mode of the material was studied by the tensile test of slow strain rate. Results of the test show that hydrogen can greatly reduce the tensile strength, plastic deformation capacity, and elongation of 30CrMnSiNi2A steel, and the higher the hydrogen concentration in the material is, the more obvious the reduction will be. Hydrogen can make the failure mode of 30CrMnSiNi2A steel change from ductile failure to quasi-joint fracture and intergranular fracture.
High-strength and lightweight alloy materials for new energy vehicles
Authors: Wang Weilong , Shen Hao , Shi Xi , Zhong Qingdong , Le Xiawen , Guo Wei
Published: August 2024

The Fe-8wt. % Al alloy ingot was obtained by melting the pure iron and the pure aluminum together. The four plate samples were prepared by cold rolling the ingots with certain thicknesses by 80%, 70%, 63%, and 50%. The four samples were annealed at 850°C, 900°C, 950°C and 1000°C in air and kept for 5 min, 10 min and 15 min before quenching. The Fe-8wt. % Al alloy ingot was obtained by melting the pure iron and the pure aluminum together. The four plate samples were prepared by cold rolling the ingots with certain thicknesses by 80%, 70%, 63%, and 50%. The four samples were annealed at 850°C, 900°C, 950°C and 1000°C in air and kept for 5 min, 10 min and 15 min before quenching. It is revealed that the sample’s structure was optimized when the sample was cold rolled by 80%, annealed at 900°C for 10 min, and quenched. This also led to a maximum extension. It is revealed that the sample’s structure was optimized when the sample was cold rolled by 80%, annealed at 900°C for 10 min, and quenched, also this led to a maximum.
Numerical study on the polydispersive effect of filler size distribution on the properties of thermal interface materials
Authors: Zong Ruoyu , Liu Bin , Jia Xiao , Wang Shijun , Li Shikun , Huai Xiulan
Published: August 2024

Advanced thermal interface materials (TIMs) are indispensable for work reliability and lifespan assurance of high-power density electronic systems by facilitating timely and effective heat dissipation. A random algorithm consisting of diluting, dropping, and stirring processes is first proposed to simulate microstructures of TIMs with continuous particle size distribution, with an accessible maximum volume fraction of 55 vol%. Then the size polydispersity impact on the thermal performance and the fluidity of TIMs is numerically investigated. Simulation results reveal that as the particle size polydispersity increases, the thermal conductivity of TIMs improves, along with the improved fluidity. Therefore, it is necessary to consider the polydispersive impact of filler size distribution in actual production and optimize the material preparation process based on the actual distribution of particles. This work provides a deeper understanding of the influence of particle polydispersity on the co-optimization of the desired attributes of TIMs.
Effect of heat treatment solid solution temperature on high-temperature performance and diffusion welding tissue of IC10 superalloy
Authors: Li Qi , Liu Fengmei , Gao Haitao , Zhang Xueying , Gao Shiyi
Published: August 2024

IC10 superalloys with small pressure and large gaps were welded by TLP diffusion welding. Based on this, the effects of heat treatment on the weld organization and welding performance of IC10 joints were discussed. The results showed that when SBM-3 was used as intermediate solder, the weld structure was similar to that of base metal under the welding process of 1250°C, 0.2 MPa, and 6h. The tensile strength was 133.7 MPa at the temperature of 1100°C. After heat treatment mechanism A, in the joint structure, a larger volume concentration of γ+γ′ phase existed in the weld, smooth transition from base metal to welded joint. Under the heat treatment mechanism A, the tensile strength at 1100°C high temperature can reach 204.6MPa (more than 85% strength of IC10). The appropriate heat treatment mechanism can get small enough micro holes and low enough porosity joints, ensuring the excellent high-temperature mechanical properties of high-temperature alloy.
3D printing turbine slicing path optimization based on FDM technology
Authors: Chen Junwei , Yu Jiaqi , Zhang Yinglong
Published: August 2024

In 3D printing technology, optimizing the slicing path is very important for printing efficiency and forming quality. In this study, the slicing path of the turbine STL model in 3D printing based on FDM technology is optimized. By improving the traditional slicing algorithm, data redundancy is reduced, and the efficiency of path generation is improved. An index-based optimization slicing algorithm is proposed, which effectively improves the efficiency of the algorithm, reduces the system consumption, and achieves more efficient slicing processing.
Optimisation design of water-fertiliser infiltration device based on TRIZ theory
Authors: Liu Taihua , Lv Bing , Zhu Wenqi , Song Chenghao , Shen Xianghao
Published: August 2024

This paper is based on functional flow and modular design to optimize the design of water-fertilizer integrated percolation irrigation device. Functional decomposition and the construction of functional structure model are completed, and the detection module and the delivery and irrigation module are identified as the modules to be optimized. Apply TRIZ theory to solve the power supply problem of the detection module in harsh environment and design the energy conversion structure. For the clogging problem of the irrigator, an anti-clogging design, labyrinth flow channel and unclogging pipe are proposed. For the labyrinth flow channel built-in elastic small pieces, can be compensated for the pressure of the irrigator outlet, labyrinth flow channel to form turbulence is not easy to form a blockage. When the pipe is clogged, through the inflatable unclogging pipe, to realize the clogging position of the air pressure impact, to complete the clogging unclogging.
Numerical simulation research on the launch process of pneumatic launch device
Authors: Li Rong , Zi Haoran , Chen Lei
Published: August 2024

In order to deal with the potential threats posed by low-altitude UAVs, an anti-UAV net-catching device was designed based on the principle of pneumatic launch. The internal ballistic calculation model of the net-catching device during the launch process was established, and the pressure-stabilizing air chamber of the device was numerically simulated. The impact of pressure, air chamber volume, gas channel diameter and barrel length on the performance of the launch device to capture the UAV was analyzed. The internal relationship between different influencing factors on the muzzle velocity and the air pressure drop of a single shot was analyzed. Selecting appropriate internal ballistic characteristics to capture UAVs at different target distances provides theoretical guidance for in-depth research on anti-UAV netting devices.
Cutting state recognition of spiral bevel gear face hobbing
Authors: Wang Jingchao , Yu Jianwu , Huang Kaifeng , Shang Zhentao , Qian Jun
Published: August 2024

To investigate the issue of chatter vibration during the face hobbing process of spiral bevel gears, this study conducted experiments on the YKA2260 gear hobbing machine, collecting 142 sets of vibration acceleration signals. The optimal combination for wavelet threshold denoising was determined based on the signal-to-noise ratio (SNR), and preprocessing of the raw signals was performed. Utilizing wavelet packet decomposition, the energy entropy of wavelet packet coefficients was extracted as feature values. A recognition model for the cutting state during the face hobbing process of spiral bevel gears was established using a Support Vector Machine, achieving a recognition accuracy of up to 98.0769%. Furthermore, the model’s high recognition accuracy for small training samples in engineering applications was validated.
Research on point pressing process of curved parts of thick plates with asymmetric double curvature of high strength steel
Authors: Ji Han , Gao Shuang , Tang Min , Yu Banhai , Li Xu
Published: August 2024

High-strength steel asymmetric double-curvature thick plate curved parts are widely used in shipbuilding, nuclear power and other industries, but their accurate forming has been a challenge due to their high strength, large size, asymmetric structure and serious springback. In this paper, the simulation analysis study of spot press forming is carried out with large-size double-curvature spherical thick shells as the research object, and the effects of mould surface size, mould radius of curvature on the results of pressing and forming of asymmetric double-curvature curved thick plate parts made of high-strength steel are analyzed. The results show that the pressing route of pressing the centre of the slab first and then carrying out point pressing along the line of symmetry to the surroundings has the best forming effect. Different mould profile dimensions and radius of curvature of the profile have a great influence on the simulated forming results.
Study on fracture toughness of ultra-thin stainless steel foils
Authors: Wang Ke , Hu Yifeng
Published: August 2024

Ultra-thin stainless steel foils have garnered significant attention due to their exceptional mechanical properties, including light weight, high strength, toughness, corrosion resistance, oxidation resistance, high temperature resistance, and superior shielding properties. In this study, we conducted experimental tests to evaluate the mechanical properties of ultra-thin stainless steel foils, focusing on the determination of Young’s modulus and yield stress for two distinct thicknesses of steel foils. Furthermore, employing both experimental and numerical simulation methodologies, we investigated the impact of wrinkles on the fracture toughness of steel foils containing central cracks subjected to tensile loading. The findings presented in this paper not only contribute to a comprehensive understanding of the mechanical behavior of ultra-thin stainless steel foils but also serve as a fundamental basis for subsequent numerical simulations and fracture toughness estimations. This research lays the groundwork for advancing the development and utilization of ultra-thin stainless steel foils across various industrial applications.
Analysis of the dynamic performance of pantograph-catenary system with posture of pan-head
Authors: Dong Yifeng , Zhou Ning , Zhang Weihua
Published: August 2024

This article focuses on the changes in the contact pressure between the pantograph and the catenary caused by variations in the pan-head posture. Starting from the kinematics and dynamics of the pantograph and based on the theories of multibody dynamics and finite element analysis, the pantograph head model is validated, and a pantograph rigid-flexible coupling model considering the flexibility of the pantograph head is established. A coupling model between the pantograph model and the rigid contact catenary is established to extract the pantograph posture and dynamic performance data during operation. By finely considering and modeling the structural characteristic parameters of the pantograph, the influence of different pantograph head characteristic parameters on the dynamic performance of the catenary system is studied. This provides a research basis for understanding the degree of influence of different characteristic parameters on the catenary dynamics.
Kinematics analysis and simulation of bionic five-finger manipulator
Authors: Zheng Jian , Zhang Lihua , Wang Zhenyao
Published: August 2024

To address the complexity of traditional manipulator structures, a bionic five-finger manipulator has been designed and developed. After introducing the manipulator’s structure and functionality, the kinematic model was established using the D-H parameter method, followed by the analysis of forward and inverse kinematics. The fingertip pose was derived using the homogeneous transformation formula, and the accuracy of the theoretical analysis was validated by comparing the mathematical and MATLAB simulation results. The Monte Carlo method was employed to determine the accessible motion space of the mechanical fingertip. Subsequently, trajectory planning for the manipulator was performed based on known initial and end finger angles. A comparison with ADAMS simulation results demonstrated the rationality of the mechanical finger’s movement space, stable speed, and compliance with actual grasping requirements. This study lays a theoretical foundation for the subsequent parameter optimization of the manipulator.
Experimental Study of Sediment Erosion in Pelton Turbine Bucket
Authors: Umar Baig Mirza , Poudel Ravi , Wang Zhengwei , Chitrakar Sailesh , Karna Aaditya , Thapa Bhola
Published: August 2024

In hydroelectric power plants (HPPs), sediment-laden water flows through entire turbines, causing components to be damaged over time. Pelton turbine components serve abrasive erosion from particle hardness, and rough surface when subjected to high flow velocities and various jet impingement angles. In this study, an experiment was conducted to examine the erosion-prone areas of a small-scale Pelton turbine bucket under actual flow conditions. For the experiment, the Pelton bucket was painted with four distinct layers of paint: red, yellow, green, and blue. These layers served as indicators, helping us to visually track the erosion process. The setup was specifically designed to inject sediment upstream of the nozzle. It operated for a significant period of 0- 30 minutes, and every 5 minutes, the erosion pattern was noted with the nozzle fully open at 10 l/s and a net head of 6m with jet impingement angle 75°, 90°, and 105°. After operating for 0-30 minutes in sediment-laden flow conditions, a pattern of erosion was revealed, showing the hot spots (areas more susceptible to erosion) during the investigation at jet angles of 75°, 90°, and 105°. The most severe erosion areas are in the bucket domain, specifically at the splitter region and the deeper upper and lower parts of the brim. The erosion mechanism was influenced by the jet diameter and impingement angle on the bucket splitter. The experiment revealed that the outer regions of the bucket, where the flow was directed outward, suffered the most severe erosion, providing evidence of particle separation at high accelerations.