Optimal Height Research Articles

Research on Dynamic Monitoring and Optimization of Lighting Environment in Clothing Workshop Based on Visual Comfort

T8 LED tubes with adjustable brightness and color temperature are installed in the workshop for workers to adjust their lighting independently. The illuminance of the workers’ working surface is dynamically monitored for one year, and the collected illuminance data are quantitatively analyzed to explore the suitable illuminance threshold and color temperature preference for workers in real scenes. The illuminance value is divided according to time period and season, which provides reference for the development of intelligent buildings. For the three workflows in the post-finishing workshop, the lighting environment was optimized based on the uniformity of illumination, and the optimal height of the lighting arrangement was determined. The optimal luminaire placement height for the bar tacking machine was found to be 1.28 m, for the auxiliary workbench it was 1.02 m, and for the ironing table it was 1.2 m.

Impacts of distributed thermal and electric contact resistance on performance and geometric optimization of thermoelectric generators

Thermal and electric contact resistance (TCR/ECR) critically impact performance and geometric optimization of thermoelectric generators (TEGs). However, conventional treatments usually ignored or simplified them as lumped variables, neglecting their actual distributions across the TEG system. In this study, we proposed a multi-physical model to characterize TEG performance with explicitly specifying TCRs/ECRs at different TEG interfaces (locations). The numerical results show that the lumped-variabletreatment led to maximal overestimations of 16.9 % and 24.5 % in the TEG output power and efficiency, respectively, compared to the results with distributed TCR in this article. Importantly, it also reveals that the TEG performance was susceptible to the TCR location—the interfaces on the cold side exerted more negative impacts than those on the hot side. Furthermore, reducing both TCR and ECR could improve TEG performance and reducing TCR is more effective. It is shown that an 80 % reduction in TCR increased the maximum TEG output power by 35.6 %, while the same reduction percentage in ECR only improved it by 8.8 %. As to geometric optimization, an optimal TE leg height equal to 0.6 mm was obtained for the maximum output power. This contrasts with previous studies without considering TCR and ECR, which always favoured shorter heights. As for copper electrodes, their optimal heights were in the range of 0.2–0.4 mm corresponding to the maximum efficiency, far smaller than those (0.7–1.2 mm) obtained when TCR/ECR were neglected. The latter even further resulted in a reduction in the maximum efficiency by more than 1 % compared to its true peak. In this study, all these numerical results clearly elucidate the important impacts of distributed TCR and ECR on TEG performance, and provide a comprehensive and balanced guideline for TEG design.

Design of a multi-scale cylindrical porous fin based on constructal theory

Porous fin (PF) has obvious advantages in heat dissipation, so it is necessary to analyze and optimize its performance. In this paper, a multi-scale cylindrical porous fin (PF) model is built. Firstly, the fin length and height ratio are chosen as the optimization variables, constructal design is conducted with the objective of complex function (CF) composed of maximum temperature difference (MTD) and pumping power consumption (PPC). Then, an artificial neural network (ANN) model is established by using data samples, and multi-objective optimization (MOO) is performed using the NSGA-II method. The findings indicated that the optimal length and height ratio of the fin are 4.763 mm and 1.017 under the conditions that the total PF envelope volume and PF-material volume are fixed. The CF is reduced by 51.0% compared with that before optimization. The multi-scale cylindrical porous fin with different heights is superior to the single-scale one with equal height. For MOO, the lowest deviation index obtained by TOPSIS or LINMAP decision-making strategy (DMS) is 0.258. For this case, the MTD is reduced by 81.9%, and the PPC is reduced by 18.7%. Therefore, the relevant optimal structure herein can be used as the optimal design solution for the multi-scale cylindrical porous fin.

Fresh maize yield in response to nitrogen application rates and characteristics of nitrogen-efficient varieties

Efficient nitrogen management is crucial in developing sustainable strategies aimed at enhancing yield while mitigating negative environmental impacts. However, limited research has focused on this aspect in the production of fresh maize. Therefore, this study analyzed nitrogen application rates and yield for 40 sweet and 44 waxy maize varieties in Zhejiang Province, China from 2015 to 2019 across five sites. Nitrogen application rates were categorized as relatively high (RHN: >300 kg ha-1 for sweet maize, >320 kg ha-1 for waxy maize) or relatively low (RLN). An increase in nitrogen application rates for both sweet and waxy maize significantly reduced nitrogen fertilizer partial productivity (R2=0.616, P<0.01; R2=0.643, P<0.01), indicating that the optimum nitrogen application rate in this study might be the lowest values (160 kg ha-1 for sweet maize and 180 kg ha-1 for waxy maize). The kernel number per ear of sweet maize had a potentially more significant impact on fresh grain yield compared to the 1,000-fresh kernel weight both under RLN and RHN. In waxy maize, 1,000-kernel weight contributed more to fresh grain yield under RLN, and kernel number ear-1 and 1,000-kernel weight cooperatively affected yield under RHN. In this study, it was observed that sweet maize required taller plant and ear height, along with an optimal ear-plant height ratio, to enhance dry matter accumulation and increase source size, particularly under RLN, to achieve a higher fresh grain yield. In contrast, a lower ear height and ear-plant height ratio of waxy maize probably contributed more to increased kernel number and weight under RLN, likely due to a lower ear height can reduce the distance between sink and source, enabling more efficient photoassimilate allocation to the ear.

Determination of fan height based on FDM nozzle temperature field analysis—an example of babbitt alloys

In this paper, the phenomenon of nozzle clogging or drooling droplets in the process of FDM metal 3D printing of tin-based Babbitt alloys was evaluated by simulation to assess the effects of different heights of cooling fans on the printer’s nozzle cooling module, and the optimal height of the fans was determined. Based on the thermal analysis results, a thermodynamic coupling analysis was carried out to analyze the thermodynamic changes of the nozzle at a given temperature. Finally, the printing trials of tin-based Babbitt alloy were carried out using self-developed forming equipment to verify the accuracy of the theory. The results show that the print quality can be effectively improved by controlling the heat dissipation module of the printer nozzle. The printed material exhibited a uniform and fine microstructure in the 3D printing trials of tin-based Babbitt alloy.

Stubble Height Impact on Forage Accumulation and Nutritive Values in Native Meadows

Forage from native prairie meadows is an important feed source in Eastern Kansas to address the challenges of shallow, acidic, and nutrient-poor soils. However, it is crucial to establish an optimal stubble height to optimize forage accumulation (FA) and nutritive value (NV). Our objective was to evaluate the impact of stubble height on FA and NV in native prairie meadows in Eastern Kansas. The study was conducted in native meadows using a randomized complete block with three replications across three locations (Parsons, Caney, and Coyville, all located in Eastern Kansas). Treatments were four stubble heights (2.5, 7.5, 12.5, and 17.5 cm). Shorter stubble height resulted in greater FA, as it removes a greater proportion of the forage accumulated. Forage accumulation was slightly higher when harvested at 7.5- than at 12.5-cm stubble height. Crude protein content increased from 2.5- to 17.5-cm stubble height with no differences between 7.5- to 12.5-cm stubble height. The opposite pattern of CP occurred for CPA (Table 3), with only 25 kg in difference from 7.5- to 12.5-cm stubble height. Stubble height did not affect fiber content (NDF and ADF) and energy content (TDN, NEL, NEG, and NEM). Thus, stubble height from 7.5 to 12.5 cm provides great FA and CPA in native prairie meadows. However, to ensure long stand life and better CP content, stubble height above 12.5 cm should be preferred, which may contribute to reducing animal supplementation costs.

Analysis of macronutrient and micronutrient intake with the incidence of stunting and wasting in toddlers 0-59 months of age at public health center Bojong, Bogor regency

Background : Stunting is defined as not achieving optimal height for age. One of the factors of stunting is caused by unbalanced nutrition. This is due to long-term nutrient intake inadequacies that potentially lead to insufficient nutrient requirements from food. Wasting often has symptoms of severe weight loss in the short term. It usually occurs when toddlers do not get a good quality and quantity of food and/or they suffer from recurrent or chronic illnesses.&#x0D; Objective : Assessing the relationship between macro-micronutrient intake with the incidence of stunting and wasting in the Bojong Health Center working area, Bogor Regency July-August 2023 Period.&#x0D; Methods : This research using cross-sectional study was conducted in the working area of Public Health Centre Bojong, Bogor Regency, Indonesia, from July 2023 to August 2023. The number of subjects is 93 subjects. Subjects were recruited using consecutive sampling, toddlers aged 0-59 months and mothers were the respondents who answered questions during interviews, 2x24-hour food recall, SQFFQ. The data in this study was obtained through direct interviews with respondents.&#x0D; Results : Subject macronutrient and micronutrient intake tended to be deficient refer to RDA 2019. There was an association (p=0.000) between the intake of energy, protein, carbohydrates, fat, Fe, Omega 3, Zn, vitamin D, and Ca with the incidence of stunting and wasting.&#x0D; Conclusions : Intakes of energy, protein, carbohydrate, fat, iron, omega-3, zinc, vitamin D, and Ca were significantly lower in children with nutritional problems (stunting and wasting) compared to RDA Indonesian Ministry of Health 2019.

Use of thermal drone in detection and assessment of larval mass temperature in decomposed rabbit carcasses.

Manual ground searches and cadaver dogs are traditional methods for locating remains, but they can be time- and resource-intensive, resulting in the decomposition of bodies and delay in victim identification. Therefore, thermal imaging has been proposed as a potentially useful tool for detecting remains based on their temperature. This study investigated the potential of a novel search technique of thermal drones to detect surface remains through the detection of maggot mass temperatures. Two trials were carried out at Selangor, Malaysia, each utilizing 12 healthy male Oryctolagus cuniculus European white rabbits and DJI Matrice 300 RTK drone China, equipped with a thermal camera; Zenmuse H20T to record the thermal imaging footage of the carcasses at various heights (15, 30, 60-100 m) for 14 days for each trial. Our results demonstrated that the larval masses and corresponding heat emissions were at their largest during the active decay stage; therefore, all the carcasses were observable in thermal images on day 5 and remained until day 7. Statistical analyses showed that (1) no statistically significant differences in thermal images between clothed and unclothed subjects (p > 0.05); (2) 15 m above ground level was proven to be the optimal height, as it showed the greatest contrast between the carcass heat signature and the background (p < 0.005). Our data suggested the potential window of detection of thermal signatures was detectable up to 7 days post-deposition. This could be an important guideline for the search and recovery teams for operational implementation in this tropical region.

Nitrogen application and cultivar effects on industrial hemp yield dynamics

AbstractRenewed interest in hemp (Cannabis sativa L., &lt;0.3% delta‐9‐tetrahydrocannabinol) production has motivated investigations into crop management and fertilizer application. Due to fertilizer regulations, soil characteristics, and unique climatic conditions in Florida, researching nutrient management for region‐specific hemp cultivation is essential. A study conducted in central Florida during 2021 and 2022 used six nitrogen (N) rates (0, 56, 112, 168, 224, and 280 kg ha−1) and five cultivars (NWG‐2730, X‐59, Bialobrzeskie, IH Williams, and Yuma) as a first effort to develop producer‐oriented fertilizer guidelines. The field experiments employed a randomized complete block design across N rates and varieties, with N applied in three split applications. The results indicated an interaction between cultivars and N rates, as expected due to their diverse genetic and geographic origins. Challenges in genetic and germination quality resulted in grain and biomass yield of two cultivars, X‐59 and Bialobrzeskie, that did not respond to the N application. Conversely, NWG‐2730, IH Williams, and Yuma cultivars demonstrated significantly higher yields within the 168–280 kg ha−1 N range. Moreover, cultivars demonstrated differing emergence counts (field count), and findings indicated a correlation between emergence and plant count at harvest (r = 0.68 and p = 0). The study also found a difference in germination count versus field count (after adjusting the seed rate depending on germination percentage). Enhanced plant count at harvest substantially elevated grain and biomass yield. The N application positively influenced plant height across all cultivars except Bialobrzeskie. Optimal plant height was achieved within the 168–280 kg N ha−1 range. Therefore, optimizing N rates and selecting cultivars (with higher emergence rates in the field) could help achieve higher biomass and grain yields.

Design and variable scale optimization of flare gas recovery process for hydrogen production

Flare systems are equipped in refining and petrochemical industries to ensure operation safety. However, flare gas sent directly to the flare system for combustion wastes energy and pollutes the environment, so it is of great significance to recover and comprehensively utilize flare gas. A new process of hydrogen production with flare gas recovery is proposed in this paper, which not only solves the problem of environmental pollution but also makes rational use of energy and improves economic benefit. Firstly, the flare gas recovery process for hydrogen production is designed by coupling the poly-refrigerant integrated cycle operation method with the chemical looping combustion sorption enhanced steam methane reforming method. Secondly, key parameters such as reactor temperature, H2O/CH4 molar ratio, and CaO/CH4 molar ratio are optimized through sensitivity analysis with CH4 conversion, H2 yield, H2 purity (dry basis), and CO2 capture rate as indicators. Thirdly, computational fluid dynamics simulation is carried out to validate the above macroscopic analysis results and further optimize the process at the mesoscopic level. The effects of different bed heights on hydrogen purity are analyzed to determine the optimal bed height for the reformer reactor, which strengthens the performance of the equipment. Finally, the process is probed by an economic analysis, which shows that 68.7 tons/year of hydrogen is produced when the recovery of methane from flare gas reaches 137.3 tons/year. This determines the economic feasibility of the process. The significance of this paper lies in: a novel green process using flare gas recovery to produce high-purity hydrogen with the conversion from waste gas to new energy realized with the concept of “turning waste into treasure”; a new way of combining meso-level and macro-level, variable-scale optimization of the process parameters; the recycling of other short-chain hydrocarbon-containing waste gases.

Calling for the future of conservation: a protocol for passive acoustic monitoring of small arboreal primates

Biodiversity conservation faces challenges due to a lack of accurate information on species occurrence. Various techniques have been used to survey species diversity and estimate population density, but monitoring species over large spatial and temporal scales remains challenging. Passive acoustic monitoring (PAM) has emerged as a cost-effective and non-invasive method for monitoring biodiversity. PAM utilizes autonomous recording units (ARUs) installed in different areas and is particularly relevant for monitoring threatened species in tropical forest regions. In the case of non-human primates, PAM has proven effective in detecting endangered species, monitoring populations, studying vocal behavior, and evaluating territory use. The black lion tamarin (Leontopithecus chrysopygus), an endangered species of the Atlantic Forest, relies on acoustic signals for communication. This study proposes a PAM protocol for monitoring arboreal primates using the black lion tamarin as a model. It reviews PAM's use in primate research and emphasizes defining target vocalizations. We recommend optimal recording conditions, including distance, height, and equipment. Recordings should be positioned high above the ground, considering the arboreal nature of primates. The choice of spatial distribution, including random placement, transects, and grids, depends on the research question and objectives. Lastly, the study addresses the recording schedule, considering periods of greater species activity, such as from sunrise to sunset. In summary, this study highlights PAM's potential for monitoring arboreal primates providing recommendations for vocalizations, recording conditions, equipment, spatial distribution, and schedules, contributing to effective monitoring, and supporting conservation efforts in tropical forests.

Factors influencing precise control of room temperature for floor heating systems in severely cold regions of China

Precise control of room temperature for floor heating systems is a key step toward intelligent heating, which is of great significance in achieving thermal comfort and energy savings. Generally, the room temperature is controlled by thermostats that are placed on a wall, far away from the occupied zone. This may cause large temperature control deviation and cannot satisfy thermal comfort of the occupants. Based on the theory of the building thermal design, this study investigated the factors influencing the heating room temperature and temperature control deviation by combining a field experiment with a numerical simulation, providing a thermostat installation location strategy. The results show that air infiltration and solar radiation are the two main factors affecting the indoor temperature field. For conventional heating systems widely used in severely cold regions of China, it is not recommended to install thermostats near the occupants, but rather on the walls. The installation location should comprehensively consider room size, air infiltration, and solar radiation. To avoid the influence of outdoor factors and internal heat sources, 1.5 m can be used as the optimal installation height. These findings provide reference for the precise control of room temperature for floor heating systems.

The Influence of the Variation in Arch Height of the Main Tayan Bridge on the Member Forces

The height of the bridge arch significantly impacts the strength and structural efficiency. Research on the height of the Tayan Bridge arch was conducted to determine the values and behaviour of member forces, structural weight, and deflection and to design the optimal arch height geometry. This research involved five variations of the arch height. The bridge structure was modelled using AutoCAD software. Relevant bridge loading data based on the SNI 1725-2016 standard was inputted into AutoCAD for structural design, and then the structure was modelled and analysed using SAP2000. The analysis results provided information on the bridge weight, deflection, and member forces. The analysis results were then compared with the bridge arch height, and this comparison was presented in the form of graphs. From the analysis results, it can be concluded that the bridge arch height has a positive linear relationship with the bridge weight. Tensile and compressive forces exhibit opposite behaviour. Increasing the arch height with constant value results in weight, deflection, and member force variations. Constantly expanding the arch height also does not lead to an increase in the stiffness of the bridge. Structurally, the optimal arch height is 42.134 meters.

A CBCT Assessment of Orthodontic Mini-Implant Placement

ABSTRACT Objectives: This study compares the precision of cone beam computed tomography (CBCT) and two-dimensional radiography for mini-implant implantation. Materials and Method: For 30 sites (in 15 patients between the ages of 13 and 26 years), the buccal interradicular region among the 2nd premolar and 1st molar was found to be the best location for mini-implants. Next, two groups of the mini-implant implantation process were created. Mini-implants were positioned at the CBCT data-identified sites in the CBCT group. Mini-implants were inserted in the RVG group by using two-dimensional digital radiography and a specially constructed guide. To assess the precision of the mini-implant implantation, post-placement CBCT images were acquired. The obtained data were statistically analyzed. Result: The two groups showed a statistically considerable variation in the mini-implant placement’s departure from the optimal height. Due to the smaller interradicular space and decreased convenience in the posterior mandibular area, two out of 15 mini-implants in the RVG group demonstrated root contact in the mandibular jaw Conclusion: The two-dimensional intraoral radiograph of the interradicular area provides sufficient information for mini-implant placement even though CBCT accurately visualizes the interradicular space in three dimensions.

Evaluation of Optimal Insertion Sites and Angles for Orthodontic Mini-Implants at the Anterior Nasal Spine Region Based on Cone-Beam Computed Tomography

Background: To infer the optimal angulation and height level of mini-implant insertion in the anterior nasal spine (ANS) region from alveolar bone depth (BD) and labial cortical bone thickness (CBT) through cone-beam computed tomography (CBCT), the influences of sex, age, and growth pattern on BD, CBT, and the starting point of the ANS were examined. Material and methods: BD and CBT were measured on CBCT median sagittal images at specific angles (0, 15, 30, 45, and 60 degrees) to simulate the angulation of insertion. The height level of the first axial image with obvious bone ridge was recorded as the start of ANS. Results: The average height of ANS start was 9.42 mm from the alveolar bone crest between the central incisors. The variations in height level and insertion angle combined, or either of them individually, significantly influenced BD and CBT, demonstrating overall decreasing trends (p &lt; 0.001). BD was not influenced by sex, age, or growth pattern (p &gt; 0.05). However, CBT was found to be correlated with sex and growth pattern, while the height level of ANS start was associated only with growth pattern, particularly in hypodivergent patients (p &lt; 0.05). Conclusion: The recommended insertion height level is 14–16 mm from the alveolar bone crest and the recommended angulation is 30–45°. An innovative inequity in the relationship between a certain height level and the insertion angulation is proposed.

Scale effect of micro ribs on the turbulent transport in an internal cooling channel

Owing to the limited supply and pressure margin in the air system, a cooling technique providing efficient heat transfer with lower flow loss is highly desirable for gas turbine blades. Microscale ribs have promised to be a potential cooling candidate. In this work, large eddy simulations are implemented to reveal the scale effect of micro ribs on the near-wall turbulent transport in a cooling channel. Considering a mechanistic study and practical applications, both single-rib and rib-array arrangements are studied with a wide range of dimensionless viscous-scaled rib heights involving the entire boundary layer. The results indicate that the rib-induced destruction and regeneration of coherent structures are, respectively, responsible for the weakened momentum transport and enhanced heat transport in the near-wall region. Using tiny ribs, regenerated quasi-streamwise vortices are mainly located in the buffer layer. The resulting turbulence burst greatly enhances wall heat transfer while keeping a lower flow loss due to the weak form drag. Regenerated hairpin vortices using tall ribs are activated in the log-law layer and intensively interact with mainstream. Along with improved wall heat transfer, the significant form drag results in a remarkably high flow loss. Accordingly, heat transfer and flow loss show different dependencies on the rib height, which contributes to an optimum height interval of ribs (e+ = 20–40) located in the high buffer and low log-law layer for maximizing the overall performance. Furthermore, for the rib-array scheme, adequate inter-rib spacing is essential to achieve turbulence regeneration for enhancing near-wall heat transport.

Experimental study on rock strata movement and stope stress distribution law under mining height regulation

AbstractWhen pressure relief mining of a non‐all‐coal protective layer, to realize the accurate regulation of the pressure relief range and pressure release value of mining height, it is necessary to carry out research on the migration of overburden and the stress distribution law of stope under mining height control. Through similar material simulation experiments, four groups of similar material simulation experimental models were established. The laws of rock strata movement and stress distribution at 2, 4, and 5 m mining heights under different geological conditions, and the laws of rock strata movement and stress distribution at 5 and 8 m mining heights under the same geological conditions were obtained. The research results show that the geological conditions and mining height do not affect the evolution of the rock strata movement range. The highest position of the strata movement and deformation is linearly related to the advancing distance of the coalface. The maximum height of rock strata movement increases abruptly when encountering the key strata, but it still has a linear relationship. The highest position of each expansion of the fracture zone has an exponential relationship with the advancing distance of the coalface. When the key strata are encountered, the maximum height of the fracture zone increases abruptly. The change in mining height only affects the distribution range of the “three zones.” The mining height controls the stress distribution of stope by adjusting the “three zones” of the roof. With the increase in mining height, the caving zone and fracture zone range increase. The corresponding pressure relief range and pressure relief value show the change law of first increasing and then decreasing. There is an optimal mining height, which can make the pressure relief effect of stope best.

A new technique for determination of the optimum cut height according to the fabric type in garment production

Purpose Fabrics, which are one of the raw materials of the clothing industry, constitute approximately 40–45% of the total cost of an apparel product. Due to the labor-intensive nature of this industry and failure to apply scientific methods along with the manufacturing processes, the wastes in the raw materials, including fabrics, become higher. Besides, quality deficiencies are encountered due to the same reasons. This study aims to determine the optimum total fabric layer height based on the fabric type during the cutting process with a straight knife cutting machine, which provided a decrease in the cutting errors. Design/methodology/approach Frequently used fabric types in an enterprise operating in organic cotton knitwear were listed. During the cutting tests, the straight knife cutting machine was used as the cutting device. The weight and thickness values of the fabrics were obtained to provide a comparison basis. Two different algorithms were created to evaluate the defective pieces according to fabric type, cutting height and error placement. Cutting resistances of these fabrics were also determined to evaluate the defect reasons. In the end, optimum total fabric layer count and total cutting height suggestions were proposed for each fabric type for a minimum cutting error. Findings At the end of this study, the error-free layers were identified per fabric type. At the same time, the optimum cutting height was suggested for each fabric basis. For 40/1 single jersey fabrics, the cutting height should be between 2.10 cm and 10.40 cm; for 30/1 single jersey fabrics, between 1.65 cm and 5.70 cm; for 20/1 single jersey fabrics, between 1.83 cm and 6.70 cm; for two-thread fleece fabrics, between 2.13 cm and 4.70 cm; and for three-thread fleece fabrics, between 0 cm and 4.90 cm. Research limitations/implications Within the scope of the study, since the products made of knitted fabric were produced more frequently and in large quantities, the study was carried out with 15 different types of knitted fabrics at 10 different layers. The same methods should be applied for woven, denim and nonwoven fabric types, which would shed light on the following studies. Originality/value Due to scarce research carried out on the cutting procedure of the clothing industry in regards to sustainability, this study aims to contribute to this area. The main difference between this study and the studies that mostly make mathematical predictions about the cutting procedure is that it is practice-oriented.

Reconfigurable UAV-aided 3D sustainable surveillance in classified air-spaces

The recent advancement of smart UAVs (Unmanned Aerial Vehicles) allows its applicability to wide-range fields covering time-critical reports, emergent item delivery, virtual emotion services and so on. In particular, the surveillance can be supported by a fleet of smart UAVs in cooperation with various system components including sensors, mobile robots, autonomous vehicles and so on. Additionally, it is crucial to consider the reconfigurable capabilities of smart UAVs leveraging for rapid movement in disregarded airspace. In this paper, we introduce a reconfigurable UAV-enabled 3D sustainable surveillance in classified air-spaces to provide energy-efficient monitoring and security surveillance enforcement. We formally define a problem to maximize the reconfigurable UAV-aided sustainable surveillance efficiency with optimal height in 3D classified air-spaces avoiding excessive resource consumption and waste. To solve this issue, two different schemes of Lined-Up and Zig-Zag are proposed. Furthermore, we analyze their performances based on the gained numerical results through expanded simulations with detailed discussions.

High-strength preload indicator inner washer forward design method

The preload indicator bolt assembly is a fastener that achieves the desired preload effect by simply tightening the preload nut within a specified range without additional measuring tools. The inner washer is a critical component in this assembly, with its outer diameter and height serving as crucial design parameters. In this paper, an equivalent mechanical model is established for the preload indicator bolt assembly. Utilizing this model, an iterative search process is developed to determine the optimal outer diameter and height of the inner washer. The analytical relationship between the bolt preload force and nut displacement is compared and validated against finite element analysis and experimental results, yielding favorable agreement. Notably, the nut tightening angle can vary within the range of 187°–242°, while the preload force exhibits a minimal variation of only ±2% for type 10-0A bolt connection (Bolt diameter and bolt pitch are φ16 mm and 1.41 mm, respectively. The material of bolt, inner ring, and flat ring are GH4169, 40CrNiMoA, and 30CrMo, respectively). This feature significantly simplifies the installation process of the preload indicator bolt assembly in real-world applications, offering great convenience. The increment in tension force on preloaded bolts under external loads exhibits an almost identical trend for both connection methods. Under the same preload force and the same eccentric working load conditions, the thickness of the connected components follows the same trend as their contact area.