Directional Distribution Research Articles

Exploring dynamics relationship between carbon emissions and eco-environmental quality in Samarinda Metropolitan Area: A spatiotemporal approach

Carbon emissions have a negative impact on climate change. Environmental quality has faced significant challenges in the last decades. Eco-environmental quality helps assess the condition of the ecological environment to support humans' civilization and development. By using emissions raster dataset, remote sensing images, and LULC data, this study explores the status of carbon emissions (CE), eco-environmental quality (RSEICs), and the dynamic relationship between both variables in Samarinda Metropolitan Area, Indonesia. This study uses the spatiotemporal approach to deepen the understanding of CE-RSEICs during 2000–2021. The methods include the analysis of CE and the principal component of RSEICs. To understand the CE-RSEICs spatial features, the directional distribution ellipse method is used. Also, this study performs CE-RSEICs coupling analysis and identifies its LULC type composition. The findings show that CE status is still on an increasing trend, concentrating in the eastern region and keeping expanding during the period. The location of the low-emission ellipse is in the southwest, while the high-emission ellipse is in the east and intersects with the core cities. The mean RSEICs value is between 0.2878 to 0.4223, which indicates that the eco-environmental quality is categorized as fairly poor to inferior. Greenness, wetness, and Csink have a positive impact on RSEICs. The very poor-class ellipse is located in the inland region, and the very good-class ellipse is in the coastal area. The CE-RSEICs coupling status shows that the majority of the area has a weaker coupling degree. However, the higher coupling degree is concentrated in the population center and built-up region, which is the settlement area. The dominance composition of settlement area in higher coupling degree shows that settlement area has an impact on increasing CE-RSEICs coupling degree. So, sustainable low carbon development in coastal metropolitan area must continue to be carried out by considering CE-RSEICs and its spatial aspects.

Analysis of the directional and spectral distributions of kinetic energy in aortic blood flow

It has been recognized that blood flow in large vessels, such as the aorta, may undergo a transition to turbulent flow in the presence of cardiovascular disorders, while flow in the healthy aorta is perceived to be laminar under normal physiological conditions. However, this perception has been challenged by several studies, highlighting the need to consider more fundamental flow characterizations. The present study aims to provide a comprehensive analysis of the directional and spectral distributions of kinetic energy in aortic flows under normal and pathological conditions. For this purpose, large-eddy simulation results for two patient-specific aortas, representing a healthy aorta and an aorta with aortic valve stenosis, respectively, were analyzed by decomposing the resolved transient velocity fields into directional and frequency components. It is shown that fundamental characteristics, such as the distinctive role of harmonics of the cardiac cycle as well as intermediate frequencies, indicate complex flow structures and turbulence over the entire thoracic aorta in both cases. The high-frequency components of kinetic energy are found to decrease by more than one order of magnitude from regions associated with complex flow features to the descending aorta. In conclusion, the capability of such analyses to effectively describe complex aortic blood flow at physiological and pathological conditions is demonstrated and motivates further efforts to achieve a more fundamental understanding of the true nature of aortic blood flow.

Revisiting the implications of Liouville's theorem to the anisotropy of cosmic rays

We present a solution to Liouville's equation for an ensemble of charged particles propagating in magnetic fields. The solution is presented using an expansion in spherical harmonics of the phase space density, allowing a direct interpretation of the distribution of arrival directions of cosmic rays. The results are found for chosen conditions of variability and source distributions. We show there are two conditions for an initially isotropic flux of particles to remain isotropic while traveling through a magnetic field: isotropy and homogeneity of the sources. In case isotropically-distributed sources inject particles continuously in time, a transient magnetic induced dipole will appear. This dipole will vanish if the system reaches a steady-state. The formalism is used to analyze the data measured by the Pierre Auger Observatory, contributing to the understanding of the dependence of the dipole amplitude with energy and predicting the energy in which the quadrupole signal should be measured.

Evaluation of Lingual Foramen in the South Indian Population Using Cone-Beam Computed Tomography: A Prospective Cross-Sectional Study.

Surgical procedures in the anterior mandibular region require a profound understanding of the complex anatomical structures to ensure patient safety. The lingual foramen (LF) and its intra-osseous canal are pivotal structures, supplying vascular and neural support to the mental region. The prevalence of LF is widely recognized, with variations among populations. The study involved 650 adult participants. Data were collected using high-resolution cone-beam computed tomography (CBCT), and statistical analysis was conducted, establishing inter-rater agreement. The population had a varied age distribution, with males comprising 53.23% and females comprising 46.77%. The median lingual canal was found in the Supra and Infra spinosum (65.38%). Most participants had lateral lingual canals (60.92%). The most prevalent lingual foramina was 4 (30.62%). The study found no significant associations between gender and LF diameter, distribution in different travel directions, or LF locations. However, males had a slightly larger diameter. The findings provide valuable insights into LF variations based on anatomical locations, and there were no statistically significant differences in measurements across different age groups. This knowledge contributes to the evolving field of oral and maxillofacial surgery, ensuring better patient outcomes.

Hybrid Distribution Model and Market Penetration of Consumer Electronics in Nigeria

In a geographically large and diverse market like Nigeria, gaining full-scale market penetration for consumer goods can be a herculean task due to inadequate transportation infrastructure, and lack of robust channel structure. This study sought to mitigate this challenge by investigating the causality between hybrid distribution model and market penetration. It specifically aimed to determine the influences of direct and indirect distribution on market penetration of consumer electronics in Nigeria. The study adopted cross-sectional research design. Primary data were obtained from 384 major distributors of consumer electronics in Port Harcourt, Calabar and Ikeja through a structured questionnaire. Snowball and quota sampling techniques were applied to recruit respondents for the survey. The data obtained were analyzed using descriptive statistics and the hypotheses of the study were tested using multiple linear regression. The findings of the study revealed that even though both direct and indirect distribution strategies had significant positive influences on market penetration of consumer electronics in Nigeria, the indirect distribution approach had a higher contribution to market penetration. Hence, the study concluded that hybrid distribution model strategically enhances the ability of manufacturers of consumer electronics to achieve extended market penetration in Nigeria. Therefore, we recommended that: manufacturers of consumer electronics should establish direct distribution outlets in Nigeria such as company warehouses, manufacturer-owned retail stores, corporate online stores, and direct sales representatives in order to effectively sell products to customers while eliminating the prospects of third-party adulterations, counterfeiting and other unwholesome practices of middlemen; and there is need for manufacturers of consumer electronics to collaborate and strategically partner with capable intermediaries like wholesale distributors, retail chain stores, independent retailers, online marketplaces, authorized dealers and market traders to achieve extended market coverage and ensure their products are extensively available in the Nigerian market.

Loan classification using a feed-forward neural network

Objectives. The purpose of the study is to construct and study the use of a feed-forward neural network to solve the problem of loan classification, as well as to conduct a comparative analysis of the neural networkbased approach with the existing approach based on logistic regression.Methods. Based on a feed-forward neural network using historical data on loans issued, the following metrics are calculated: cost function, Accuracy, Precision, Recall, and measure, calculated on Precision and Recall values. Polynomial parameters and the principal component method are used to determine the optimal set of input data for the studied neural network.Results. The impact of data normalization on the final result was analyzed, the influence of the number of units in the hidden layer on the outcome was evaluated using a two-stage method and the Monte Carlo method, the effect of balanced data use was determined, the optimal threshold value for output layer of the neural network under investigation was calculated, the optimal activation function for the hidden layer units was found, the effect of increasing input indicators through missing values imputation and the use of polynomials of varying degrees was studied and the redundancy in the existing set of input indicators was analyzed.Conclusion. Based on the results of the research, we can conclude that the use of a direct distribution network to solve problems of loan classification is appropriate. Compared to logistic regression, implementing a solution using a feed-forward neural network requires more time and computing resources. However, the obtained most important values of Accuracy and measure are higher than those calculated using logistic regression [1].

Prediction model for vertical distribution of oil particles under thermal plume and displacement ventilation in a machining workshop

Oil particle concentrations exhibit an inhomogeneous distribution in large-space machining workshops with a displacement ventilation system. The inhomogeneous distribution can lead to variations in the required supply air volume used to control the indoor particle concentration at different heights. To rapidly calculate the particle concentration distribution in the vertical direction, this study established a zonal particle concentration prediction model based on the mass and energy balance by considering the interaction between the heat source thermal plume, wall thermal plume, and supply airflow. An experiment was conducted in a scaled chamber to validate the proposed prediction model. The result showed that the relative error between the prediction model and experiment ranged from −17% to 10%. A case study was performed to demonstrate the applicability of the prediction model to the control of a displacement ventilation system. Using the prediction model, the control system can maintain the particle concentration in the work area below 0.5 mg/m³with variable particle source emission rates and reduce the supply air volume by at least 24% and 55% compared with the variable and constant air volume systems, respectively, neither of which can address the inhomogeneous distribution of oil particle concentration. The prediction model can also be used for the design of displacement ventilation systems when the inhomogeneous particle concentration distribution is considerable.

Study on Temperature Field Uniformity of Dynamic Induction Heating for Camshaft of Marine Diesel Engine

This paper focuses on the study of the induction heating process of a camshaft in a marine diesel engine. A three-dimensional finite element model for dynamic induction heating is established using the finite element method of multi-physical field coupling, aiming to investigate the temperature uniformity of the cam during this process. Three elements are analyzed in this study: the moving speed, the gap between the induction coil and the workpiece, and the width of the induction coil. These factors allow for an analysis of the temperature distribution in the thickness direction and contour line direction of the cam under various conditions. On this basis, an equivalent parameter about the temperature uniformity in the thickness direction of the cam is proposed to guide the selection of the camshaft induction heating process parameters.

Mesoscale modelling of North Sea wind resources with COSMO-CLM: model evaluation and impact assessment of future wind farm characteristics on cluster-scale wake losses

Abstract. As many coastal regions experience a rapid increase in offshore wind farm installations, inter-farm distances become smaller, with a tendency to install larger turbines at high capacity densities. It is, however, not clear how the wake losses in wind farm clusters depend on the characteristics and spacing of the individual wind farms. Here, we quantify this based on multiple COSMO-CLM simulations, each of which assumes a different, spatially invariant combination of the turbine type and capacity density in a projected, future wind farm layout in the North Sea. An evaluation of the modelled wind climate with mast and lidar data for the period 2008–2020 indicates that the frequency distributions of wind speed and wind direction at turbine hub height are skillfully modelled and the seasonal and inter-annual variations in wind speed are represented well. The wind farm simulations indicate that for a typical capacity density and for SW winds, inter-farm wakes can reduce the capacity factor at the inflow edge of wind farms from 59 % to between 54 % and 30 % depending on the proximity, size and number of the upwind farms. The efficiency losses due to intra- and inter-farm wakes become larger with increasing capacity density as the layout-integrated, annual capacity factor varies between 51.8 % and 38.2 % over the considered range of 3.5 to 10 MW km−2. Also, the simulated efficiency of the wind farm layout is greatly impacted by switching from 5 MW turbines to next-generation, 15 MW turbines, as the annual energy production increases by over 27 % at the same capacity density. In conclusion, our results show that the wake losses in future wind farm clusters are highly sensitive to the inter-farm distances and the capacity densities of the individual wind farms and that the evolution of turbine technology plays a crucial role in offsetting these wake losses.

HBCalculator: A Tool for Hydrogen Bond Distribution Calculations in Molecular Dynamics Simulations.

Hydrogen bonds, crucial noncovalent interactions in molecular systems, significantly impact biological, chemical, and energy-related processes; therefore, characterizing hydrogen bond information is of importance to fundamental studies. This work introduces the HBCalculator, a Tcl-based tool integrated with VMD for calculating 1D and 2D distributions of hydrogen bond density and strength. The tool facilitates spatial analysis, overcoming limitations in existing packages that lack direct spatial distribution output. By employing HBCalculator in MD simulations, three systems of cellulose/water and graphene/water interfaces, were tested to showcase its functionality. The 1D and 2D hydrogen bond distributions reveal insights into interfacial properties, reflecting the impact of material hydrophobicity. The simplicity of usage, along with its potential for diverse molecular systems, positions HBCalculator as a valuable tool for researchers exploring hydrogen bond networks.

EVALUATION OF AIRPORT RAIL SERVICES BASED ON MINIMUM SERVICE STANDARDS (SPM)

One of the factors the Yogyakarta government built Yogyakarta International Airport was because the capacity of the Adisutjipto airport was only able to accommodate 1.2 million passengers but in reality the number of passengers could reach five times the capacity. Due to the very busy flight schedule and inadequate airport capacity, since 2020 the average flight has been diverted to Yogyakarta International Airport (YIA) "quoted from the official Adisutjipto airport website". The location of the airport which is far from the city center has had an impact on the development of mass transportation modes of the Railroad as a direct connector between the airport and Yogyakarta city center. The YIA Airport Train Station will begin operating in October 2021. In this relatively new period, it is necessary to evaluate the service facilities on the Airport Railroad and at the YIA Airport Station. The purpose of this research is to prove to what extent services both on the train and at the YIA airport station have met minimum service standards and to produce new innovations on the effectiveness of train scheduling related to the level of passenger satisfaction. The government itself has Minimum Service Standards for the Transport of People by Train which are listed in the Regulation of the Minister of Transportation of the Republic of Indonesia, Number PM 63 of 2019 concerning Minimum Service Standards for the Transport of People by Train, at Stations and on Trips. The regulation has 6 types of services, namely: Safety, Security, Reliability/Organization, Convenience, Convenience, and Equality. To find out whether the 6 types of services meet service standards, an evaluation can be carried out using qualitative methods with data collection techniques by direct observation in the field and through questionnaires, so that it is known that the implementation of minimum service standards at the Airport Railway and at YIA Airport Station . The stages required in conducting this research include: preparation, problem identification, data collection method by collecting primary data, namely through direct observation and online questionnaire distribution, both of which are analyzed descriptively, data evaluation, discussion, as well as conclusions and suggestions. The results obtained from this study are that there are still several service facilities that are inappropriate or not available in the station such as toilets, prayer rooms, no smoking prohibited signs, no seats available for persons with disabilities and so on, and the contents of the first aid kit are not found on the train , the temperature inside the train is not suitable, not all passengers can sit especially when the train is crowded and so on. Through the results of these observations to ensure the level of service, questionnaires were distributed and analyzed. Broadly speaking, the questionnaire shows that passengers expect the availability of toilets and prayer rooms at the station, the number of seats in the waiting room needs to be increased, the temperature in the room is considered, and the addition of the train departure schedule should be adjusted to the arrival and departure of the plane so that passengers do not wait too long.
 Keywords: Minimum Service Standards (SPM), Stations, Airport Railroad.

MACHINE LEARNING AND ARTIFICIAL NEURAL NETWORK TECHNOLOGIES IN THE CLASSIFICATION OF POSTKERATOTOMIC CORNEAL DEFORMITY

Backgraund: A thorough analysis of both the optical and anatomical properties of the cornea in patients after anterior radial keratotomy is of particular importance in choosing the optical strength of an intraocular lens in the surgical treatment of cataracts and other types of optical correction. The variability of the clinical picture of postkeratotomic deformity (PCRD) determines the need to develop its classification and is an important task of modern ophthalmology.
 Aims: to develop an automated system of classification of corneal PCRD using machine learning and an artificial neural network based on the analysis of topographic maps of the cornea.
 Materials and methods: depersonalized results of the analysis of medical records of 250 patients aged 59.63±5.95 (from 46 to 76) years were used as the material. The analysis of 500 maps of the relief-topography of the anterior and posterior surfaces of the cornea and 3 stages of machine learning of the PCRD classification were carried out.
 Results: Stage 1- analysis of the relief topography of the anterior and posterior surfaces of the cornea allowed us to fix the numerical values of the elevation of the anterior and posterior surfaces of the cornea in three ring-shaped zones. At stage 2, in the course of deep machine learning, a direct distribution neural network was selected and created. 8 auxiliary parameters describing the shape of the anterior and posterior surfaces of the cornea were established. Stage 3 was accompanied by obtaining algorithms for the classification of PCRD depending on the ratio of test and training samples, which ranged from 75 to 91%..
 Conclusion: The use of artificial neural network algorithms can become a useful tool for automatic classification of postkeratotomic corneal deformity in patients who have previously undergone radial keratotomy.

Pengaruh Perceived Ease of Use, Brand Image, dan Harga terhadap Keputusan Pembelian (Studi pada Pengguna Transportasi Online Maxim di Kota Medan)

Purchasing decisions are one of the important factors in marketing a service. The lack of consumer purchase interest in Maxim online transportation services makes Maxim less recognized by the people of Medan. Factors that can influence purchasing decisions such as perceived ease of use, brand image, and price. The form of research used is quantitative with an associative approach. The population in this study is the community of Maxim online transportation service users in Medan City, with a sample of 96 respondents, with a sampling technique using purposive sampling. Primary data were obtained through direct distribution of questionnaires and secondary data were obtained through literature studies. The results of this study showed that Perceived Ease of Use did not significantly affect the Purchase Decision, with a sig value of 0.203 > 0.05. Brand Image has a significant positive effect on Purchase Decisions with a significance of 0.000 < 0.05. Price also has a significant positive effect on Purchasing Decisions with significance levels of 0.005 < 0.05. In simultaneous testing, the variables Perceived Ease of Use, Brand Image, and Price had a simultaneous effect with an influence rate of 46.8%, while the remaining 53.2% was influenced by factors outside this research model.

Weight Bias Among Certified Nurse-Midwives and Certified Midwives: Findings From a National Sample.

Weight bias toward individuals with higher body weights permeates health care settings in the United States and has been associated with poor weight-related communication and quality of care as well as adverse health outcomes. However, there has been limited quantitative investigation into weight bias among perinatal care providers. Certified nurse-midwives (CNMs)/certified midwives (CMs) attend approximately 11% of all births in the United States. The aims of this study were to measure the direction and extent of weight bias among CNMs/CMs and compare their levels of weight bias to the US public and other health professionals. Through direct postcard distribution, social media accounts, professional networks, and email listservs, American Midwifery Certification Board (AMCB)-certified midwives were solicited to complete an online survey of their implicit weight bias using the Implicit Association Test and their explicit weight bias using the Antifat Attitudes Questionnaire, Fat Phobia Scale, and Preference for Thin People measure. A total of 2257 midwives participated in the survey, yielding a completion rate of 17.7%. Participants were mostly White and female, with a median age of 46 years and 11 years since AMCB certification. More than 70% of midwives have some level of implicit weight bias, although to a lesser extent compared with previously published findings among the US public (P <.01) and other health professionals (P <.01). In a subsample comparison of female midwives to female physicians, implicit weight bias levels were similar (P >.05). Midwives also express explicit weight bias, but at lower levels than the US public and other health professionals (P <.05). This study provides the first quantitative research documenting weight bias among a national US sample of perinatal care providers. Findings can inform educational efforts to mitigate weight bias in the perinatal care setting and decrease harm.

SOFIA/HAWC+ Far-Infrared Polarimetric Large Area CMZ Exploration Survey. I. General Results from the Pilot Program

We present the first data release of the Far-Infrared Polarimetric Large Area CMZ Exploration (FIREPLACE) survey. The survey was taken using the 214 μm band of the HAWC+ instrument with the SOFIA telescope (19.″6 resolution; 0.7 pc). In this first data release we present dust polarization observations covering a ∼0.°5 region of the Galactic center’s central molecular zone (CMZ), approximately centered on the Sgr B2 complex. We detect ∼25,000 Nyquist-sampled polarization pseudovectors, after applying the standard SOFIA cuts for minimum signal-to-noise ratios in fractional polarization and total intensity of three and 200, respectively. Analysis of the magnetic field orientation suggests a bimodal distribution in the field direction. This bimodal distribution shows enhancements in the distribution of field directions for orientations parallel and perpendicular to the Galactic plane, which are suggestive of a CMZ magnetic field configuration with polodial and torodial components. Furthermore, a detailed analysis of individual clouds included in our survey (i.e., Sgr B2, Sgr B2-NW, Sgr B2-Halo, Sgr B1, and Cloud E/F) shows they have fractional polarization values of 1%–10% at 214 μm, with most of the emission having values <5%. A few of these clouds (i.e., Sgr B2 and Cloud E/F) show relatively low fractional polarization values toward their cores and higher fractional polarization values toward their less dense peripheries. We also observe higher fractional polarization toward compact H ii regions, which could indicate an enhancement in the grain alignment in the dust surrounding these sources.

Morphological complexity and azimuthal disorder of evolving pore space in low-maturity oil shale during in-situ thermal upgrading and impacts on permeability

In-situ thermal upgrading is used to tune the pore system in low-maturity oil shales. We introduce fractal dimension (D), form factor (ff) and stochastic entropy (H) to quantify the heating-induced evolution of pore morphological complexity and azimuthal disorder and develop a model to estimate the impact on seepage capacity via permeability. Experiments are conducted under recreated in-situ temperatures and consider anisotropic properties—both parallel and perpendicular to bedding. Results indicate that azimuthal distribution of pores in the bedding-parallel direction are dispersed, while those in the bedding-perpendicular direction are concentrated. D values indicate that higher temperatures reduce the uniformity of the pore size distribution (PSD) in the bedding-parallel direction but narrow the PSD in the bedding-perpendicular direction. The greater ff (> 0.7) values in the bedding-parallel direction account for a large proportion, while the dominated in the bedding-perpendicular direction locates within 0.2–0.7, for all temperatures. The H value of the bedding-parallel sample remains stable at ∼0.925 during heating, but gradually increases from 0.808 at 25 °C to 0.879 at 500 °C for the bedding-perpendicular sample. Congruent with a mechanistic model, the permeability at 500 °C is elevated ∼1.83 times (bedding-parallel) and ∼6.08 times (bedding-perpendicular) relative to that at 25 °C—confirming the effectiveness of thermal treatment in potentially enhancing production from low-maturity oil shales.

Seepage disturbance mechanism and interface force of cylindrical barrier in fracture

The fluid flow in the crack is disturbed by the contact area. The parallel-plate model with a circular cylindrical contact area is regarded as an idealization of the real contact fracture, and a computational fluid dynamics simulation is performed on it to analyze the interaction between the contact area and the flow around it. The size of the contact area controls the disturbance intensity to the flow velocity magnitude and the disturbance range to the velocity direction. Due to the existence of viscosity, the flow near the wall has a larger shear rate. The intermediate transition region is located between the contact area and the fracture lateral wall and does not contain the region with strong viscous friction caused by the wall. The flow velocity magnitude in the intermediate transition zone changes exponentially in space and has a peak value near the contact area. After the flow bypasses the contact area, the inertial effect caused by the increase in flow velocity magnitude in the local flow channel controls the generation and development of the low-velocity region and the asymmetric degree of the velocity direction distribution. Both the mechanical aperture and the inlet flow velocity affect the stress distribution on the surface of the contact area. The occurrence of the nonlinear flow behavior of fracture seepage and nonlinear change trend of logarithmic drag coefficient curve can be predicted with the same critical Reynolds number. These results provide a useful guide for further exploring the local flow and the surface stress distribution of the local interior geometric property in a single rough-walled fracture on the mesoscopic scale.

Spatial distribution of intangible cultural heritage resources in China and its influencing factors

Exploring the spatial distribution of China’s intangible cultural heritage resources and its influencing factors is an important foundation for their protection and development and a key step toward the integration of culture and tourism. To analyse the geographical distribution patterns of China’s 3610 intangible cultural heritage resources and their influencing factors, we comprehensively applied methods such as spatial analysis and geodetectors. The main findings are as follows: (1) In terms of spatial distribution, China’s intangible cultural heritage resources are unevenly distributed, with an overall agglomeration-type distribution. The distribution in the north‒south direction is more significant, with more resources in the east than in the west and more resources in the south than in the north. (2) In terms of the spatial distribution of various types of intangible cultural heritage sites, North and East China have always been areas with a high kernel density. (3) In terms of spatial trends, there is a clear correlation between the distribution of intangible cultural heritage resources and the state of economic development and historical and cultural heritage, i.e., the more economically developed and culturally rich a region is, the more resources of intangible cultural heritage there are. (4) The causes of the distribution of China’s intangible cultural heritage resources are complicated, the influence of social factors is much greater than that of natural factors, and multidimensional interactions have a relatively significant impact. This study is conducive to the planning and protection of China’s intangible cultural heritage resources at the national and regional levels and provides a reference for the sustainable development of China’s intangible cultural heritage resources.

Scalable, Green, Flexible Photochromic Bacterial Cellulose for Multicolor Switching, Photo-patterning, and Daily Sunlight UV Monitoring.

Sustainable, durable, and diverse photochromic smart textiles based on bacterial cellulose (BC) have emerged as attractive candidates in UV-sensing applications due to the green and easy functionalization of BC. However, existing BC-based photochromic textiles lack photochromic efficiency and combining fastness. In this study, a green strategy for in situ fermentation is developed to achieve the directional distribution of functional particles and remarkable photochromism in photochromic bacterial cellulose (PBC). The unique functional design obtained by regulating the photochromic dye distribution in 3D nanonetworks of PBCs during in situ growth affords a more uniform distribution and high fastness. Benefiting from the uniform distribution of photochromic dyes and adequate utilization of the 3D network structure, more surface area is provided to receive and utilize the photon energy from the UV rays, making the photochromic process more effective. The as-prepared PBCs exhibited rapid (within 1min) and stable (30 cycles) discoloration and multicolor selectivity. Their simple preparation process and exceptional wearability, e.g., their flexibility, lightweight, and air permeability, make them suitable for various applications, including tunable color switching systems, photopatterning, and daily sunlight UV monitoring. This study provides empirical value for the biofabrication of photochromic textiles and wearable flexible UV sensors.

Three-Dimensional Path Tracking of Over-Actuated AUVs Based on MPC and Variable Universe S-Plane Algorithms

Autonomous Underwater Vehicles (AUVs) are widely used for the inspection of seabed pipelines. To address the issues of low trajectory tracking accuracy in AUV inspection processes due to uncertain ocean current disturbances, this paper designs a new dual-loop controller based on Model Predictive Control (MPC) and Variable Universe S-plane algorithms (S-VUD FLC, where VUD represents Variable Universe Discourse and FLC represents Fuzzy Logic Control) to achieve three-dimensional (3-D) trajectory tracking of an over-actuated AUV under uncertain ocean current disturbances. This paper uses MPC as the outer-loop position controller and S-VUD FLC as the inner-loop speed controller. The outer-loop controller generates desired speed instructions that are passed to the inner-loop speed controller, while the inner-loop speed controller generates control input and uses a direct logic thrust distribution method that approaches optimal energy consumption to distribute the thrust generated by the propellers to the over-actuated AUV, achieving closed-loop tracking of the entire trajectory. When designing the outer-loop MPC controller, the actual control input constraints of the system are considered, and control increments are introduced to reduce control model errors and the impact of uncertain external disturbances on the actual AUV model parameters. When designing the inner-loop S-VUD FLC, the strong robustness of the variable universe fuzzy controller and the easy construction characteristics of the S-plane algorithm are combined, and integral action is introduced to improve the system’s tracking accuracy. The stability of the outer loop controller is proven by the Lyapunov method, and the stability of the inner loop controller is verified by simulation. Finally, simulations show that the over-actuated AUV has fast tracking processes and high tracking result accuracy under uncertain ocean current disturbances, demonstrating the effectiveness of the designed dual-loop controller.