Flat Type Research Articles

Experimental Determination of a Mixture Composed of Camisea Natural Gas and CO2 Laminar Burning Velocity

The aim of this work is to provide new experimental data on laminar burning velocities for a new synthetic mixture composed of Camisea natural gas and CO2. It was found that the relevant published experimental background data are l imited to mixtures composed of methane and CO2; considering the fact that Camisea natural gas is widely used in Peru, this experimental research will serve as a supportive resource for further experimental and industrial implementations in this country, such as the design and modeling of new engines or industrial burners that are designed to be fueled by this mixture. An experimental setup for analyzing three types of flame geometry, which is feasible to implement for a wide range of conditions, was built in PUCP PI0735 laboratory and all the measurements were obtained for a range of mixtures (0%, 21.2%, 28.5%, 38.9%, 50% CO2) and ratios from around 0.55 to 0.95 at atmospheric conditions. The laminar burning velocities results obtained were analyzed in groups based on %CO2. In addition, the experimental margin error was determined by considering all the sources. The following conclusions were reached: (1) The laminar burning velocity decreases with the increase in CO2 percentage in the mixture due to the CO2 decreasing the flame temperature effect. (2) The flat flame type provided the highest value of burning velocity for each group of CO2 percentage in which it appears. (3) The highest obtained laminar burning velocity value was 22.64 ± 0.15 cm/s, for a flat flame with a ratio of 0.72 and 29.98% of CO2, while the lowest obtained value was 6.78 ± 0.15 cm/s for a conical trunk flame with a ratio of 0.59 and 49.83% of CO2. (4) The highest evaluated CO2 percentage was 50.97% for a conical trunk flame with a ratio of 0.69 and a burning velocity value of 11.04.

Computational fluid dynamics analysis of flat plate type solar collector under different fin variables to enhance air-based heat transfer

Purpose This study begins by outlining the core principles of how flat plate solar collectors (FPSC) operate and the underlying mechanisms of heat transfer. It underscores the pivotal role of fin patterns in enhancing convective heat transfer. Design/methodology/approach The primary objective is to examine the impact of diverse fin patterns on the thermal performance of FPSCs. The study involves the development of a 3D-CFD model for FPSC using the computational fluid dynamics (CFD) software ANSYS FLUENT. The analysis is conducted for variable mass flow rates (mf) ranging from 0.01 to 0.05 kg/s with an interval of 0.02 kg/s. Each flow rate is assessed for three distinct fin patterns: straight plate fins, V-shaped fins and wavy fins. Recognizing the variation in solar radiation intensity throughout the day, the analysis is executed at six different time points ranging 10:00 a.m. to 03.00 p.m. with a time interval of 1.00 h. Findings It is observed that the wavy fin pattern with a mass flow rate of 0.01 kg/s exhibited the highest outlet temperature, showing a significant temperature difference of 12.4 K at noon. Conversely, the V-shaped fin pattern with a mf of 0.05 kg/s has the lowest temperature difference value, measuring only 3 K. The analysis included the calculation of thermal efficiency for each case, revealing that the V-shaped fin pattern at a mf of 0.05 kg/s and a sun radiation intensity of 885.42 W/m2 achieved the maximum instantaneous thermal efficiency (ηth) of 34.7%. The study records the outlet air temperature for all of these combinations and presents the data graphically in the paper. Originality/value The findings of the simulations indicate that the thermal performance that is ηth and maximum temperature of outlet air of FPSCs can be improved through the utilization of variable fin patterns.

Factors affecting distribution of dose in horizontal direction during irradiation

Recording and managing the dose of x-rays in an x-ray machine is an important part of the data. In addition, recording and managing radiation dose data in x-ray devices plays an important role in providing transparency of radiation dose to medical staff and patients by quantifying the radiation dose data. Four mobile diagnostic X-ray units were used to analyze the dose by spatial location. The dose distribution by location was analyzed by identifying and analyzing the dose by angle for both image intensifier and flat panel detector types. The three-dimensional space of the radiation area consisted of 27 sides, and the structure of the space was assumed to be horizontal X, Y, and Z sides and vertical A, B, and C sides, and the dose analysis was performed at the assumed position. On the longitudinal side, the highest dose tissue (highest μSv/min) is B_Center : (R.B.M, Colon, Lung, Stomach, Breasts, Remainder of body) - 330.404 μSv/min, and the lowest dose tissue (lowest μSv/min) is 0.002 μSv/min on the (Skin, Bone surface, Salivary glands, Brain) side at C_270°. The findings from diagnostic X-ray devices have emphasized the importance of managing radiation exposure when using the devices and may raise questions about the management of radiation protection measures to protect the health of healthcare personnel and patients. This can be expected to advance the organization of the use of radiation devices in a safe healthcare environment. A system for managing data will be useful as an indicator to guide medical staff using the equipment and patients participating in procedures and surgeries where they can minimize their dose and avoid harm.

Energetic and economic analysis of a novel concentrating solar air heater using linear Fresnel collector for industrial process heat

Industrial processes share a relevant portion of global energy consumption. A large variety of high energy-demanding industrial processes need hot air in the medium temperature range, provided by natural gas combustion or by electricity. Hot air is used as a medium in a large variety of processes such as drying, curing, and thermal treatments of several products and materials. Heat can be provided by solar thermal technologies aimed at the sustainable industry. Non-concentrating flat plate type solar collectors can directly heat air up to 100 °C while higher temperatures can be achieved using linear concentrating technology. In this study an innovative system using linear Fresnel collectors directly provides hot air for the industry up to 350 °C, avoiding the need for liquid heat transfer fluids. Accordingly, the installation is simplified, and lower installation and maintenance requirements are expected compared to other solar technologies. The present studies provide an energetic and economic analysis of the concentrating solar air heater, considering a medium-scale benchmark as a reference case in representative European locations. The results indicate that the solar technology here presented can be economically competitive with conventional natural gas heating, having a huge potential for fossil fuel source replacement in hot air based industrial processes.

Achievement of advanced alkaline Ni-Zn batteries with good durability at a high areal capacity of 10 mAh cm−2 via the synergistic regulation of dual electrolyte additives

Though obvious advantages in terms of safety, cost, environmental compatibility and electrochemical performance (e.g, power and energy density), the commercial application of alkaline Ni-Zn batteries, a number of traditional aqueous batteries, is still under great restrictions owing to the poor durability (commonly less than 100 cycles). In this work, an effective electrolyte modification process using dual additives of hydroxy-rich carboxymethyl cellulose (CMC) that can inhibit hydrogen evolution reaction (HER) and suppress Zn dendrites, and benzyltrimethylammonium bromide (BTMAB) that can mitigate passivation and oxygen evolution reaction (OER) is developed. Meanwhile, our home made C coated ZnO (ZnO@C) microspheres were used as initial anode materials without the using of any other expensive composites. With a fixed areal charge capacity of 10 mAh cm−2, the flat type full cell matched with commercial Ni(OH)2 cathode can deliver a high average discharge capacity of ∼9.6 mAh cm−2 (corresponding to an average CE of 96 %) for a long lifespan of over 390 cycles, which drops to 8.2 mAh cm−2 at 400th cycle accompanied by the appearance of a peak in the charge curve. The cumulative discharge capacity of a full cell can reach ∼4,000 mAh cm−2 in 420 cycles’ cycling, much larger than that using commercial Zn/ZnO anode and the ZnO@C anode in unmodified or single additive modified electrolyte (less than 1,500 mAh cm−2).

Design and Optimization of the Shape of a Single-person Submersible based on ANSYS

Due to the complex growth environment of wild sea cucumbers, the difficulty and low efficiency of traditional ROV identification, at present, wild sea cucumber fishing is mainly obtained through manual fishing, in order to ensure the life safety of divers and improve the fishing efficiency of sea cucumbers, new ideas and solutions for single-man submersibles suitable for shallow water operations are proposed. Under the condition of ensuring the driver's operating space, the shape and structure of an easy-to-process manned submersible are designed to optimize its resistance performance. Creo was used to establish a model of a single-man submersible for shape design, and three design schemes were proposed: scheme 1 flat spindle type, scheme 2 imitation unmanned boat type, and scheme 3 imitation airfoil type. The drag performance of the single-man submersible is simulated and analyzed by using the Fluent module in the analytical fluid dynamics simulation software Ansys, and the results show that the drag performance of scheme 3 imitation airfoil type is better than that of other schemes.The conclusion was verified by simple experiments.It provides effective reference information for the subsequent structural optimization of single-man submersibles.

AdaBoost algorithm for the recognition of young women’s body shapes based on 2D images

Classifying and recognizing the human body shape during human body measurements based on 2D images helps to improve measurement accuracy. In this paper, 430 young women's 2D body images were selected to establish 2D body datasets. The characteristic indices used to represent the body shape in 2D images were extracted by computer vision technology, namely the body height pixel value, projected unit area, and projected area ratio of the front and side of the body. The two-step cluster model was used to classify the body shape into three clusters: the tall, flat, and medium fatness type; the short, thin, and medium roundness type; and the round, fat, and medium height type. Then, the decision tree model and AdaBoost algorithm, an ensemble learning algorithm with the decision tree as the weak classifier, were used to recognize the body shape. The results show that the recognition accuracy of the decision tree recognition model was 93.19%. The body shape recognition method using AdaBoost achieved a better recognition effect than the decision tree model, and the recognition accuracy of the test set reached 97.35%. Through comparative study, we found that the recognition accuracy of the 2D body shape recognition method based on AdaBoost was improved and that the recognition accuracy was relatively stable. This study provides a new method for the recognition of human body shape in clothing customization and online shopping.

Characteristics and Simulation of Icing Thickness of Overhead Transmission Lines across Various Micro-Terrains

The hazard of ice accretion on overhead power circuits is significant, yet predicting it is very difficult. The key reason lies in the shortage of sufficient observational data on ice thickness, and previous studies have also rarely taken into account micro-terrain and micro-meteorological conditions. In response to the challenge of simulating overhead line icing, this study introduces a new icing simulation technique that fully considers the effects of micro-terrain and micro-meteorology. For this technique, typical micro-terrains of overhead line areas are first identified by using high-resolution elevation data, and the icing thickness characteristics in different micro-terrains are analyzed. Subsequently, icing thickness simulations for different micro-terrains are conducted. The results indicate that during the icing process, the icing thickness ranges from 5 mm to 8 mm under three types of micro-terrain, namely, “uplift type”, “alpine drainage divide type” and “canyon wind channel type”, whereas the icing thickness is less than 5 mm in the “flat type” of micro-terrain. This finding suggests that the first three micro-terrain types facilitate icing on overhead transmission lines due to the condensation and uplifting effects of water vapor caused by terrain. However, flat terrain lacks the conditions necessary for water vapor accumulation and thus is not easy to form icing. The results are advantageous for the deployment of overhead power lines in intricate terrain. It is advisable to steer clear of regions susceptible to icing, and endeavor to install circuits in level territories whenever feasible. In addition, the simulated icing thickness under different terrains is in good agreement with the observations. Specifically, the correlation coefficient between simulated and observed icing thickness is significant at the 0.99 confidence level, and the deviations between them are within 0.5 mm. This signifies that the forecasting methodologies employed are dependable and possess significant implications as a reference for disaster prevention and mitigation efforts.

Analysis of clinical characteristics and curative effects of 169 patients with bilateral sudden sensorineural hearing loss

Objective: To analyze the clinical characteristics, curative effect related factors and follow-up situation of bilateral sudden sensorineural hearing loss (BSSHL). Methods: The clinical data of 169 patients(338 ears) with BSSHL were retrospectively summarized, and the demographic characteristics, predisposing factors, concomitant symptoms and diseases, and audiological characteristics were statistically described. Additionally, influencing factors of curative effect and prognosis were statistically analyzed. Results: Among the 169 patients, 50.9% (86/169) of patients had at least one incentive, with cold and fatigue being the most common incentives(both 23/169). There were high rates of accompanying symptoms including tinnitus (150/169, 88.8%) and dizziness (100/169, 59.2%). Hypertension(49/169, 29.0%)and diabetes(23/169, 13.6%)were the most common concomitant diseases observed. Most cases exhibited all frequencies involvement, with flat type and total deafness type accounting for 83.1%(281/338 ears). The most common degree of hearing loss was total deafness(86/338 ears), with approximately 60.1%(203/338 ears) of the cases being severe or worse. The total effective rate of treatment was only 29.0%, but it increased to 39.5% for patients with course of disease≤14 days, however, when course of disease>30 days, the effective rate decreased sharply to 3.6%, showing a significant difference between these two groups(χ2=13.776,<0.01). Different types of hearing curves showed statistically significant difference in efficiency(χ2=14.782, P<0.01). Comparing the hearing improvements of 28 BSSHL patients from admission to discharge and from discharge to follow-up, it was found that the hearing improvement of the two groups showed statistically significant difference at the frequencies of L-250 Hz, L-500 Hz, R-125 Hz, R-250 Hz and R-500 Hz(Z value was -2.495, -3.083, -3.970, -3.388 and -3.264 respectively, all P<0.05). The proportion of patients with elevated serum IgE was much higher than that of the normal population. Conclusion: BSSHL patients suffer from serious hearing loss, and many also experience tinnitus and vertigo symptoms. Due to the poor efficiency of treatment, it is better for patients to be treated within 30 days of onset. For patients of hearing loss in the low frequency range, hearing improvement is more significant during hospitalization. And the occurrence of BSSHL may involve an immune mechanism.

Experimental Investigation of the Behavior of SlFCON Column under Eccentric Monotonic Load

Abstract This research delves into the performance of Slurry Infiltrated Fibrous Concrete (SIFCON) columns when subjected to eccentric monotonic loading, through the examination of twenty columns until their point of failure. The research addresses gaps in existing literature by examining the effects of various parameters, including fiber type, volume fraction, and eccentricity ratio, on SIFCON column performance. Results reveal significant correlations between the studied parameters and the structural behavior of SIFCON columns. The investigation shows how the ultimate load affect by the eccentricity ratio, for instance, the hook end steel fiber with a volume fraction of 6%, where the ultimate load decreased by a factor of 0.25 when the eccentricity ratio changed from 0.1 to 0.5. Furthermore, increasing the volume fraction of steel fibers significantly enhances the energy absorption of SIFCON columns. For instance, with the hook-end steel fiber and an eccentricity ratio of 0.3, the energy absorption increased by a factor of 2.76 when the volume fraction of steel fiber changed from 4% to 9%. The type of fibers used plays a pivotal role in the material behavior of SIFCON, with the straight micro fiber exhibiting an ultimate load 2.17 times greater than flat crimped steel fiber types when the volume fraction was 9% and the eccentricity ratio was 0.3. Finally, based on the experimental results, an interaction diagram has been established for three types of SIFCON: straight micro steel fiber with a volume fraction of 12%, hook end steel fiber with volume fractions of 6% and 4%.

Study of the variation of the leading edge of a railway crane on the aerodynamic characteristics

The front body design of the railway crane is flat or bluff type. The design causes a large drag, so the railway crane requires high fuel consumption to drive. Therefore, this study aims to modify the front body of the railway crane by applying the shape of the leading edge to reduce drag. This research also investigates the effect of leading-edge angles on aerodynamic characteristics. The method used is computational fluid dynamics, using the flow simulation feature of the Solidworks research licence software. This study considered three variations of leading edge angle (40°, 45° and 50°). The simulation results show that the larger the leading edge angle, the lower the drag coefficient value. In addition, the simulation shows that there is a high air pressure at the front of the railway crane with the bluff shape, while the modified railway crane with the leading edge applied has a lower air pressure at the front. Furthermore, the results and discussion in this article present the simulation results showing the velocity streamline and pressure contour of each model.

Transport Characteristics and Potential Source Areas of PM2.5 in Yangquan City Under Different Pollution Levels

Based on the PM2.5 monitoring data, NCEP data, and the meteorological data of the weather situation analysis at the corresponding time in Yangquan City from 2020 to 2022, using the HYSPLIT4 backward trajectory model, multi-station potential source contribution factor analysis （MS-PSCF） and trajectory density analysis （TDA） were introduced to study the differentiation and classification of PM2.5 transport channels and potential sources in Yangquan City. The results showed that： ① The PM2.5 pollution in Yangquan was mainly concentrated in Yangquan and Pingding, whereas the pollution in Yuxian was relatively light. The proportion of days with different pollution levels and the average and maximum values of PM2.5 concentration in Yangquan and Pingding were significantly higher than those in Yuxian, and the distribution characteristics of PM2.5 were closely related to the local special terrain. ② The amount of PM2.5 pollution and the concentration of PM2.5 in different pollution levels were the highest in light wind weather. The influence of east-west regional transport on PM2.5 pollution times and PM2.5 concentration of Yangquan and Pingding was obvious, and the contribution of east wind was significant. The influence of local pollution sources was the main factor in the moderate pollution weather in Yuxian County. ③ There were four main ground conditions for the generation and maintenance of moderate or above pollution weather： warm low pressure type （22%）, high pressure front （bottom） type （54%）, high pressure back type （14%）, and pressure equalization field （10%）. High pressure front （bottom） type was the main ground situation causing the increase in PM2.5 concentration. There were two types of upper air conditions, namely, flat westerly flow type （78%） and northwest flow type （22%）. The upper westerly flow type was the main upper air condition that caused the increase in PM2.5 concentration. ④ The results of transport channels and potential source areas of PM2.5 with different pollution levels obtained by MS-PSCF and TDA were consistent. The main transport channels of PM2.5 were the northeast, southeast, and northwest channels, whereas the northeast and southeast channels were short-distance transport routes, which were the main routes causing the increase in PM2.5 concentration. The northwest channel was consistent with the northwest dust transport channel, belonging to long-distance transmission. The main potential source areas of PM2.5 pollution were located in the central and western parts of Hebei and the southeast part of Hebei, the northeast part of Henan and its junction with the southwest part of Shandong, and the southeast part of Shanxi.

Metrology analysis and thoughts of literatures on tinnitus associated with sudden deafness based on CiteSpace

Objective: To explore the incidence of sudden deafness accompanied with tinnitus, the selection of examination protocols and treatment, and to provide reference for the establishment of new guidelines for sudden deafness. Methods: CiteSpace software was used for analysis and data mining to analyze and summarize the computer-retrieved articles on diagnostic examination and treatment of sudden deafness accompanied with tinnitus collected from CNIC, Wanfang and Web of Science databases from 2011 to 2021. Results: A total of 207 randomized controlled studies were retrieved in this study, including 121 in Chinese and 86 in English. Finally, 74 Chinese literatures and 16 English literatures were included. Among the 74 valid Chinese literatures, 64 (86.5%) were accompanied with tinnitus, 58 (78.4%) with dizziness/vertigo, 25 (33.8%) with aural fullness, 10 (13.5%) with headache, 4 (5.4%) with insomnia, 4 (5.4%) with a mixture of dizziness and tinnitus, and 2 (2.7%) with vomiting. Among the 16 English literatures, 15 (93.8%) were accompanied with tinnitus, 12 (75.0%) with vertigo, 1 (6.3%) with aural fullness, and 1 (6.3%) with a mixture of various symptoms. Among the 64 Chinese articles mentioning tinnitus, only 9 mentioned tinnitus matching tests, and 1 mentioned that the treatment for tinnitus accompanying symptoms was sound therapy and psychological counseling. The incidence rates of tinnitus accompanying four different types of sudden deafness, from low to high, are as follows: low-to-mid frequency, 82.4%; mid-to-high frequency, 90.7%; complete deafness, 92.4%; and flat type, 92.8%. Conclusion: Tinnitus is the most common accompanying symptom of sudden deafness, and tinnitus matching test is an effective evaluation method. When establishing a scientific, comprehensive, and systematic diagnosis and treatment system or guidelines for sudden deafness, attention should be paid to the diagnosis and treatment of tinnitus symptoms and their adverse psychological reactions, in order to reduce the incidence of tinnitus patients in the later stage of recovery from sudden deafness.

Melting of W/Cu flat type component for main limiter and its impact on plasma operation in EAST experiments

A type of actively cooled W/Cu flat-type component with high heat exhaust capacity was installed as limiter during the EAST spring plasma campaign in 2022, aiming to support the long pulse operation. Unfortunately, severe melting phenomena with obvious droplets ejection of the flat-type W/Cu limiter was repeatedly monitored by CCD and IR cameras, which not only induced the failure of component but also seriously influenced plasma operation. The high temperature around midplane of W/Cu flat-type main limiter is identified to be closely connected with ICRF induced fast ions loss. Indeed, the surface temperature of W/Cu flat-type main limiter was too high to ignore. The damage of flat-type structure, however, usually started between the joint interface of W plates and CuCrZr heat sink material. Such damage would in turn lead to the gradual increase of surface temperature which eventually would cause melting of W plates. Once melting events occurred on the W/Cu flat-type main limiter, the vast majority of cases would result in plasma disruption. Moreover, the damage of main limiter would rapidly deteriorate. Hence, more attention should be paid to how to improve the fatigue lifetime of the joint interface. Such test results of flat-type W/Cu component for limiter are important references for the improvement and application of W/Cu flat-type component for high heat flux area in fusion devices.

Benefits of amplification for unaided speech discrimination in age-related hearing loss with flat type audiogram

Benefits of amplification for unaided speech discrimination in age-related hearing loss with flat type audiogram

Algorithm, Progresses, Datasets and Validation of GLC_FCS30D: the first global 30 m land-cover dynamic product with fine classification system from 1985 to 2022

Abstract. Land cover change information plays an indispensable role in environmental monitoring, climate change research, agricultural planning, urban development, biodiversity conservation, and natural disaster risk assessment. Recently, the free access of Landsat imagery and improvement of computation capacity especially supported by Google Earth Engine platform provides great chance in time-series land-cover change monitoring. We used the stratified land-cover monitoring strategy and time-series Landsat imagery to develop a novel global 30 m land-cover dynamic product with fine classification system from 1985 to 2022 (GLC_FCS30D). Firstly, we used the multitemporal classification to generate the time-series impervious surfaces, wetlands and tidal flat products. Then, we proposed to combine the continuous change detection algorithm and local adaptive updating model to capture the land-cover changes, and to generate a new global 30 m land-cover dynamic product (impervious surfaces, wetlands and tidal flat types were excluded in this step). Next, after overlapping the three multitemporal classification products and the time-series dynamical land-cover dataset, the novel GLC_FCS30D was developed, which contained 35 fine land-cover types. Lastly, using the global 84526 validation points in 2020, the GLC_FCS30D was validated to show the great performance with an overall accuracy of 80.88%, and had obvious advantages over other global land-cover products in diversity of land-cover types and mapping accuracy.

Gastric dysplastic lesions in Helicobacter pylori-naïve stomach: Foveolar-type adenoma and intestinal-type dysplasia.

Reports of Helicobacter pylori (Hp)-naïve gastric neoplasm (HpNGN) cases have been rapidly increasing due to the recent increase in the Hp-naïve population in Japan. Most HpNGNs exhibit the gastric immunophenotype and a low malignant potential regardless of histological type. Especially, foveolar-type gastric adenoma (FGA) and intestinal-type gastric dysplasia (IGD) rarely progress to invasive carcinoma. FGA is a foveolar epithelial neoplasm that occurs in the fundic gland (oxyntic gland) mucosa and is classified as the flat type or raspberry type (FGA-RA). The flat type is a large, whitish flatly elevated lesion while FGA-RA is a small reddish polyp. Genomically, the flat type is characterized by APC and KRAS gene mutations and FGA-RA by a common single nucleotide variant in the KLF4 gene. This KLF4 single-nucleotide variant reportedly induces gastric foveolar epithelial tumorigenesis and activates both cell proliferation and apoptosis, leading to its slow-growing nature. IGD consists of an intestinalized epithelial dysplasia that develops in the pyloric gland mucosa, characterized as a superficial depressed lesion surrounded by raised mucosa showing a gastritis-like appearance. Immunohistochemically, it exhibits an intestinal or gastrointestinal phenotype and, frequently, p53 overexpression. Thus, IGD shows unique characteristics in HpNGNs and a potential multistep tumorigenic process.

Tracking dynamics characteristics of tidal flats using landsat time series and Google Earth Engine cloud platform

Tidal flats serve as vital spatial resources within coastal wetlands and play crucial roles in biological habitat preservation, environmental conservation, and human development. However, accurately delineating their extent from instantaneous remote sensing images poses challenges, owing to the dynamic interplay between seawater and land. Therefore, this study utilized the consistency of remote sensing satellites and developed a multi-feature decision approach based on the long-term remote sensing datasets and the Google Earth Engine (GEE) cloud platform for determining the spatial extent, classifying types, and mapping the spatial-temporal distribution of the tidal flats. Initially, a multi-temporal image stack was compiled from the filtered remote sensing images. Subsequently, the modified normalized difference water index (MNDWI) and automated water extraction index (AWEI) were calculated to establish the maximum and minimum water surfaces using the extreme value composite algorithm (EVCA). The Otsu algorithm and spatial overlay analysis method were then utilized to accurately delineate the spatial extent of the tidal flats. Additionally, the Normalized Difference Vegetation Index (NDVI) was utilized to accurately identify tidal flat types. Post-processing involves elevation data and mathematical morphological methods to mitigate the impact of permanent water bodies. Finally, the accuracy of the extracted spatial extent and types of tidal flats was evaluated. The efficacy and practicality of the proposed method were validated using the Zhoushan Archipelago and Landsat time series in China. The results revealed the following: (1) the acquired tidal flat information exhibited evident boundaries and accurate types, achieving an overall accuracy (OA) of 94.80 % and a Kappa coefficient of 0.89; (2) the area of tidal flats in the Zhoushan Archipelago increased from 2,182.19 ha in 1985 to 3,761.21 ha in 2020, with an average annual increase of 45.12 ha and an average annual increase rate of 1.57 %; and (3) over 35 periods, the area transformed from other land types to tidal flats amounted to 2,895.74 ha, while the area converted from tidal flats to other land types totaled 1,651.90 ha. The three islands with the most rapid growth in tidal flat area were Liuheng Island, Dachangtu Island, and Daishan Island, with changes of 675.68 ha, 380.47 ha, and 362.63 ha, respectively. This method can offer an automated, swift, and accurate approach for tidal flat extraction, demonstrating high precision and practical effectiveness, thereby providing robust technical support for coastal resource surveys.

Origami of multi-layered spaced sheets

Two-dimensional (2D) origami tessellations such as the Miura-ori are often generalized to build three-dimensional (3D) architected materials with sandwich or cellular structures. However, such 3D blocks are densely packed with continuity of the internal material, while for many engineering structures with multi-physical functionality, it is necessary to have thin sheets that are separately spaced and sparsely connected. This work presents a framework for the design and analysis of multi-layered spaced origami, which provides an origami solution for 3D structures where multiple flat sheets are intentionally spaced apart. We connect Miura-ori sheets with sparsely installed thin-sheet parallelogram-like linkages. To explore how this connectivity approach affects the behavior of the origami system, we model the rigid-folding kinematics using analytic trigonometry and rigid-body transformations, and we characterize the elastic-folding mechanics by generalizing a reduced order bar and hinge model for these 3D assemblies. The orientation of the linkages in the multi-layered spaced origami determines which of three folding paths the system will follow including a flat foldable type, a self-locking type, and a double-branch type. When the origami is flat foldable, a maximized packing ratio and a uniform in-plane shear stiffness can be achieved by strategically choosing the link orientation. We show possible applications by demonstrating how the multi-layered spaced origami can be used to build deployable acoustic cloaks and heat shields.

Morphology of the proximal tibiofibular joint does not affect the type of lateral malleolus fracture and syndesmotic ligament injuries: A computed tomography-based study

IntroductionThe Proximal Tibiofibular Joint (PTFJ) is a synovial joint with anatomical variations located between the anteromedial surface of the fibula and the posterolateral facet of the tibia. These anatomical variations are believed to contribute to different biomechanical behaviors in both the knee and ankle joint and play a role in both physiological and pathological movements. Therefore, the morphology of the proximal tibiofibular joint may play a decisive role in the characteristics of ankle fractures and syndesmotic ligament injuries. Materials and methodsIn this retrospective comparative our CT database was searched between January 2015 and December 2022. Following inclusion criteria were used: Availability of knee CT scans for the fractured ankle, external rotation-type injuries (pronation external rotation and supination external rotation fractures). After applying the exclusion criteria (Plafond fractures, supination adduction and pronation abduction type fractures, pathological fractures, patients with previous fractures or surgeries around the knee, patients with previous fractures or surgeries around the knee, proximal tibiofibular arthrosis), 44 CT scans (mean age = 42.8 ± 14.1) confirmed eligible for further analysis. On each scan following measurements were performed: Coronal and sagittal PTFJ inclination angle, Joint obliquity, fibula head-tibia joint distance and tibia plateau-fibular axis angle. ResultsThe study consisted of 24 (54.5 %) male and 20 (45.5 %) female patients. According to the proximal fibular inclination, 29 cases (65.9 %) were of the oblique type, and 15 cases (34.1 %) were of the horizontal type. The distribution of PTFJ variations was as follows: 17 (38.6 %) concave, 4 (9.1 %) convex, 7 (15.9 %) atypical, and 16 (36.4 %) flat type. Regarding the PTFJ joint contour, the distribution was 13 (29.5 %) type a, 11 (25 %) type b, and 20 (45.5 %) type c. There was no relationship between measurements of PITFJ morphology and the type of ankle fracture and/or syndesmosis injury (p > 0.05). ConclusionPTFJ morphological features are not associated with rotational ankle fractures and syndesmotic ligament injuries.