Three-dimensional Transportation Research Articles

Lossy Image Compression with Stochastic Quantization

Introduction. Lossy image compression algorithms play a crucial role in various domains, including graphics, and image processing. As image information density increases, so do the resources required for processing and transmission. One of the most prominent approaches to address this challenge is color quantization, proposed by Orchard et al. (1991). This technique optimally maps each pixel of an image to a color from a limited palette, maintaining image resolution while significantly reducing information content. Color quantization can be interpreted as a clustering problem (Krishna et al. (1997), Wan (2019)), where image pixels are represented in a three-dimensional space, with each axis corresponding to the intensity of an RGB channel. The purpose of the paper. Scaling of traditional algorithms like K-Means can be challenging for large data, such as modern images with millions of colors. This paper reframes color quantization as a three-dimensional stochastic transportation problem between the set of image pixels and an optimal color palette, where the number of colors is a predefined hyperparameter. We employ Stochastic Quantization (SQ) with a seeding technique proposed by Arthur et al. (2007) to enhance the scalability of color quantization. This method introduces a probabilistic element to the quantization process, potentially improving efficiency and adaptability to diverse image characteristics. Results. To demonstrate the efficiency of our approach, we present experimental results using images from the ImageNet dataset. These experiments illustrate the performance of our Stochastic Quantization method in terms of compression quality, computational efficiency, and scalability compared to traditional color quantization techniques. Conclusions. This study introduces a scalable algorithm for solving the color quantization problem without memory constraints, demonstrating its efficiency on a subset of images from the ImageNet dataset. The convergence speed of the algorithm can be further enhanced by modifying the update rule with alternative methods to Stochastic Gradient Descent (SGD) that incorporate adaptive learning rates. Moreover, the stochastic nature of the proposed solution enables the utilization of parallelization techniques to simultaneously update the positions of multiple quants, potentially leading to significant performance improvements. This aspect of parallelization and its impact on algorithm efficiency presents a topic for future research. The proposed method not only addresses the limitations of existing color quantization techniques but also opens up new possibilities for optimizing image compression algorithms in resource-constrained environments. Keywords: non-convex optimization, stochastic optimization, stochastic quantization, color quantization, lossy compression.

Quantitative study on the photoemission of AlGaN nanoarrays based on the three-dimensional transportation within a four-step process.

Photocathodes play a crucial role in photoelectronic imaging and vacuum electronic devices. The quantum efficiency of photocathodes, which determines their performance, can be enhanced through materials engineering. However, the quantum efficiency of conventional planar photocathodes remains consistently low, at around 25%. In this paper, we propose what we believe is a novel structure of AlGaN nanowire array to address this issue. We investigate the photoemission characteristics of the nanowire array using the "four-step" process, which takes into account optical absorption, electron transportation, electron emission, and electron collection. We compare the quantum efficiency of nanowire arrays with different structure sizes and Al components. After studying the effect of incident light at various angles on the nanowire array photocathode, we identify the optimal dimensional parameters: a height of 400∼500 nm and a wire width of 200∼300 nm. Furthermore, we improved the collection efficiency of the photocathode by introducing a built-in/external electric field, and obtained a 104.4% enhancement of the collection current with the built-in electric field, meanwhile the photocurrent was increased by 87% compared to the case without the external electric field. These findings demonstrate the potential of optimizing photocathode performance through the development of a novel model and adjustment of parameters, offering a promising approach for photocathode applications.

Magnetic-Actuated Jumping of Droplets on Superhydrophobic Grooved Surfaces: A Versatile Strategy for Three-Dimensional Droplet Transportation.

On-demand droplet transportation is of great significance for numerous applications. Although various strategies have been developed for droplet transportation, out-of-surface three-dimensional (3D) transportation of droplets remains challenging. Here, a versatile droplet transportation strategy based on magnetic-actuated jumping (MAJ) of droplets on superhydrophobic grooved surfaces (SHGSs) is presented, which enables 3D, remote, and precise manipulation of droplets even in enclosed narrow spaces. To trigger MAJ, an electromagnetic field is utilized to deform the droplet on the SHGS with the aid of an attached magnetic particle, thereby the droplet acquires excess surface energy. When the electromagnetic field is quickly removed, the excess surface energy is partly converted into kinetic energy, allowing the droplet to jump atop the surface. Through high-speed imaging and numerical simulation, the working mechanism and size matching effect of MAJ are unveiled. It is found that the MAJ behavior can only be observed if the sizes of the droplets and the superhydrophobic grooves are matched, otherwise unwanted entrapment or pinch-off effects would lead to failure of MAJ. A regime diagram which serves as a guideline to design SHGSs for MAJ is proposed. The droplet transportation capacities of MAJ, including in-surface and out-of-surface directional transportation, climbing stairs, and crossing obstacles, are also demonstrated. With the ability to remotely manipulate droplets in enclosed narrow spaces without using any mechanical moving parts, MAJ can be used to design miniaturized fluidic platforms, which exhibit great potential for applications in bioassays, microfluidics, droplet-based switches, and microreactions.

WormSpace μ-TAS enabling automated on-chip multi-strain culturing and multi-function imaging of Caenorhabditis elegans at the single-worm level on the China Space Station.

As a model organism for space biology experiments, Caenorhabditis elegans (C. elegans) has low demand for life support and strong resistance to unfavorable environments, making experimentation with C. elegans relatively easy and cost-effective. Previously, C. elegans has been flown in several spaceflight investigations, but there is still an urgent need for analytical platforms enabling on-orbit automated monitoring of multiple phenotypes of worms, such as growth and development, movement, changes of biomarkers, etc. To solve this problem, we presented a fully integrated microfluidic system (WormSpace μ-TAS) with an arrayed microfluidic chip (WormChip-4.8.1) and a replaceable microfluidic module (WormChip cartridge), which was compatible with the experimental facility on the China Space Station (CSS). By adopting technologies of programmed fluid control based on liquid medium CeMM as well as multi-function imaging with a camera mounted on a three-dimensional (3D) transportation stage, automated and long-term experimentation can be performed for on-chip multi-strain culturing and bright-field and fluorescence imaging of C. elegans at the single-worm level. The presented WormSpace μ-TAS enabled its successful application on the CSS, achieving flight launch of the sample unit (WormChip cartridge) at low temperature (controlled by a passive thermal case at 12 °C), automated 30-day cultivation of 4 strains of C. elegans, on-orbit monitoring of multiple phenotypes (growth and development, movement, and changes of fluorescent protein expression) at the single worm-level, on-chip fixation of animals at the end of the experiment and returning the fixed samples to earth. In summary, this study presented a verified microfluidic system and experimental protocols for automated on-chip multi-strain culturing and multi-function imaging of C. elegans at the single-worm level on the CSS. The WormSpace μ-TAS will provide a novel experimental platform for the study of biological effects of space radiation and microgravity, and for the development of protective drugs.

A Research on the Coordinated Development of the Transportation System and Socio-economy in the Guanzhong Plain Urban Agglomeration of China

Transportation plays an important role in the coordinated development of urban agglomeration economy and society. It is an important tool to improve the level of coordinated development. This study takes the Guanzhong Plain urban agglomeration as the research area, which has a good foundation in comprehensive three-dimensional transportation network and needs to be improved in regional economic and social integration, and discusses the coordinated development of the economy and society in this area from the perspective of transportation system. Firstly, discuss the current situation of transportation and economic and social development in the Guanzhong Plain urban agglomeration; Secondly, analyze the problems in the coordinated development of transportation and regional economy and society; Finally, by integrating literature research, the coupling mechanism and improvement path between urban smart transportation and port economy and the Guanzhong Plain urban agglomeration are proposed, in order to improve the mechanism and system for coordinated economic and social development in the western region, and provide scientific reference and policy recommendations for promoting the benign interaction between transportation and regional economic and social development.

Traffic safety and public health in China – Past knowledge, current status, and future directions

Transportation-related harms have developed into a social disease, threatening public safety and health in China. We aimed to increase the global understanding of traffic safety and public health in China from past knowledge, current status, and future directions by collecting, collating, and analyzing the Chinese traffic incidents reported in the published literature. A systematic search of China National Knowledge Infrastructure, Weipu, and published articles referenced in PubMed, Web of Science and ProQuest between January 1, 1988 and April 30, 2023 was performed. China encountered the first recorded traffic accident as early as three thousand years ago in the Shang Dynasty. An increase in vehicle capacity and velocity increased the traffic risks during the transition from rickshaws and livestock to motor vehicles in varying traffic environments. Humans are not only the decisive factor of a large number of vehicles, traffic routes, and environmental variables, but also the victims at the end and starting point of traffic accidents. Injuries (mechanical force, burns) and diseases (traffic-related air pollution, noise) caused by traffic activities not only threaten public health, but also cause risks to safe driving. Analysis of traffic activities and biomarkers promotes the treatment of traffic injuries in ethology and medicine. China prepared for the construction of healthy transportation in the “decade of road safety” toward an estimation of worldwide road traffic injuries in 2030. Improvement of traffic safety concerning public health under the “Outline of the National Comprehensive Three-dimensional Transportation Network Planning” in China will propel the realization of worldwide traffic environmental advancement.

Three-dimensional bio-convection mechanism and heat transportation of nanofluid induced by magnetic field

There are several uses for bio-convection mechanisms, such as in sedimentary pools, fuel models, and microbially accelerated oil restoration. These are the basis of motile microorganisms which are applied to improve the mixability of fluid and tiny nanoparticles because they are accountable for biological transmission procedure. This work examines the bio-convective nanoparticles fluid flow and electrically conducting incompressible magneto-hydrodynamic flow of nanofluid towards a chemically reactive stretchable surface. Buongiorno model is considered here, which incorporates Brownian motion and thermophoretic diffusion, is employed in this study to explain how nanofluids improve heat transfer. The controlling boundary layer nonlinear PDEs are converted into ODEs by utilizing certain suitable similarity approaches. Numerical scheme is adopted to solve the transformed ordinary differential equations. The main findings of this research are that the magnetic field slows motion of the fluid when the thermal and mass buoyancy forces speed it up, and that thermophoretic diffusion increases the temperature and concentration of dimensionless fluids, resulting in stronger concentration and thermal boundary layers. The Brownian motion, concentration exponent, and chemical reaction parameters show an inverse relationship between temperature and concentration. Additionally, the first-order chemical reaction creates a lighter concentration boundary layer while the magnetic field’s presence due to impact of thermal and mass buoyancies helps to lower the heat transfer rate and shear stress. The findings show that while the Nusselt number and wall shear stress values are declining, the microorganism number is increasing.

Intelligent Amphibious Ground-Aerial Vehicles: State of the Art Technology for Future Transportation

Amphibious ground-aerial vehicles fuse flying and driving modes to enable more flexible air-land mobility and have received growing attention recently. By analyzing the existing amphibious vehicles, we highlight the autonomous fly-driving functionality for the effective uses of amphibious vehicles in complex three-dimensional urban transportation systems. We review and summarize the key enabling technologies for intelligent flying-driving in existing amphibious vehicle designs, identify major technological barriers and propose potential solutions for future research and innovation. This paper aims to serve as a guide for research and development of intelligent amphibious vehicles for urban transportation toward the future.

Experimental study on residual bearing capacity of full-size fire-damaged prestressed concrete girders

With the increasing development of three-dimensional transportation network, the probability of bridge fire accidents is increasing year by year, which leads to reduced bearing capacity of the bridge exposed to fire. Existing bridge detection and evaluation methods are not suitable for bearing capacity evaluations of fire-damaged bridge, since material degradation or localized damage of structural members caused by elevated temperature are not considered. This paper took actual fire-damaged bridge as a case study to analyze the influence of fire on residual bearing capacity as well as bending test on two 20 m span hollow slab girders with different degrees of damage. The prestress loss, failure mode, load–displacement curve, and residual bearing capacity were tested. A method integrated the FDS (Fire Dynamics Simulator) and the FEA (Finite Element Analysis) was proposed to calculate the actual process of bridge fire and mechanical property of fire-damaged girders. The dimensional temperature fields around the bridge and internal temperature field in a concrete hollow slab girder during the fire were obtained. Based on the research results of mechanical properties of concrete and prestressed tendon under elevated temperature, the mechanical numerical model considering internal temperature field was established; The failure mode and residual bearing capacity of fire-damaged girders were simulated. The results show that the post-fire residual bearing capacity mainly depends on the maximum temperature of prestressed tendons. The higher the temperature of prestressed tendons is, the lower the residual bearing capacity is. In the case bridge, compared to the girders at ambient temperature, bearing capacity of the two test girders decreased by 17.6 % and 15.1 %, respectively. The method proposed in this paper can be used to evaluate the post-fire bearing capacity of fire-damaged concrete girder bridges.

Impacts of the walking environment on mode and departure time shifts in response to travel time change: Case study in the multi-layered Hong Kong metropolis

Three-dimensional (3D) transportation space is one of the most important characteristics of multi-layered cities; however, fine-scale built environment factors about facilities that support the 3D walking environment were unavailable in understanding travelers’ behaviors before heading to the Big Data era. Using both small (questionnaire survey) and big (large-scale geospatial) data, we conducted a case study in Hong Kong, a well-known vertical metropolis with a multi-modal transportation system. We analyzed mode and departure time shift behaviors in response to travel time change for 2927 participants and examined the impacts of new variables derived from a 3D pedestrian network dataset and potential influencing factors identified in the literature. The results from the mode shift model indicated that having more efficient pedestrian networks, as measured by the total length of walkways and the provision of mobility aid facilities (e.g., travellators, escalators), is effective in promoting mode shift behaviors. Meanwhile, our departure time shift model revealed that having more comfortable walkways, as measured by travel attitude and the provision of mobility aid facilities, increases users’ willingness to make departure time shifts from peak hours. These findings imply that a more efficient and comfortable walking environment facilitates mode and departure time shift behaviors in daily travel. Improving the building and management of walking environments would contribute to a more integrated multi-modal transport system.

Urban Network Spatial Connection and Structure in China Based on Railway Passenger Flow Big Data

China’s transportation industry has made great achievements in the past 40 years of reform and opening up. At the same time, it has gradually accumulated a series of problems. These problems have led to closer and more complex social and economic connection within and between regions of different scales. The existing research only carries out the characteristic analysis of urban network spatial connection and pattern from a single perspective such as “flow space” theory, spatial interaction model and accessibility method, and fails to accurately describe the complex socio-economic relations between regions. Based on the big data of railway passenger flow, this study selected weighted average travel time, railway network density, and the economic connection model to express the urban network spatial connection and structure of China in 2016 from the perspectives of time, space, and interaction. In 2016, the accessibility, connectivity, and total urban external economic connection of the railway network showed a trend of declining from the east to the west. The top 50 cities ranked by interurban economic connection were all located in the central and eastern regions and showed “diamond shape” distribution characteristics. The four diamond-shaped pairs were Beijing-Tianjin-Hebei, Yangtze River Delta, Pearl River Delta, and Chengyu urban agglomerations. This shape was basically in line with the T-shaped space that has existed for a long time in China’s regional development. The accessibility, connectivity, and total external economic connection of national-level urban agglomerations were greater than those of regional-level urban agglomerations, and far greater than those of local-level urban agglomerations. The results showed that there was a mismatch between the layout of the railway network and the population. It will still be necessary to focus on strengthening the construction of transportation infrastructure in urban agglomerations and densely populated areas in the future. This study enriches the “flow space” theory, more fully describes urban network spatial connection and structure in China by considering the three perspectives of time, space, and interaction, and can provides reasonable suggestions for the development of national comprehensive three-dimensional transportation network planning, regional spatial structure optimization, and sustainable development.

Three-dimensional Li-ion transportation in Li2MnO3-integrated LiNi0.8Co0.1Mn0.1O2

Ni-rich layered cathodes (LiNixCoyMnzO2) have recently drawn much attention due to their high specific capacities. However, the poor rate capability of LiNixCoyMnzO2, which is mainly originated from the two-dimensional diffusion of Li ions in the Li slab and Li+/Ni2+ cation mixing that hinder the Li+ diffusion, has limited their practical application where high power density is needed. Here we integrated Li2MnO3 nanodomains into the layered structure of a typical Ni-rich LiNi0.8Co0.1Mn0.1O2 (NCM811) material, which minimized the Li+/Ni2+ cationic disordering, and more importantly, established grain boundaries within the NCM811 matrix, thus providing a three-dimensional diffusion channel for Li ions. Accordingly, an average Li-ion diffusion coefficient (DLi+) of the Li2MnO3-integrated LiNi0.8Co0.1Mn0.1O2 (NCM811-I) during charge/discharge was calculated to be approximately 6*10−10 cm2 S−1, two times of that in the bare NCM811 (3*10−10 cm2 S−1). The capacity delivered by the NCM811-I (154.5 mAh g−1) was higher than that of NCM811 (141.3 mAh g−1) at 2 C, and the capacity retention of NCM811-I increased by 13.6% after 100 cycles at 0.1 C and 13.4% after 500 cycles at 1 C compared to NCM811. This work provides a valuable routine to improve the rate capability of Ni-rich cathode materials, which may be applied to other oxide cathodes with sluggish Li-ion transportation.

Observer-Based Nonlinear Control for Tower Cranes Suffering From Uncertain Friction and Actuator Constraints With Experimental Verification

Tower cranes are a class of important and useful tools for the transportation of large cargoes, especially in high building construction. Moreover, the combination of jibs' rotational movements and trolleys' translational movements can fulfill three-dimensional payload transportation in a huge outdoor workspace. However, complicated dynamics and different unfavorable environmental conditions in practice make the effective control of tower cranes very challenging. In this article, based on the original dynamic models without any linearization manipulations, we present a new output feedback control method to accomplish rapid jib and trolley positioning and payload sway suppression. In particular, the velocity signals are accurately obtained by an elaborately designed observer, instead of numerical differentiation manipulations to the measurable output variables (which may distort the original velocities to some extent). Based on the velocity estimates, the suggested controller can also handle uncertain friction. Additionally, the actuator constraints are fully considered during controller design, i.e., the calculated control inputs are both within the permitted ranges, thereby avoiding actuator saturation and degrading the control performance. For the entire closed-loop system, including the proposed controller, the state observer, and tower cranes, the asymptotic stability is strictly proven by Lyapunov-based techniques. Finally, some comparative and robustness verifications are implemented by hardware experiments.

Analysis of the cesium distribution in the JT-60SA negative ion sources for steady long-pulse operation.

To realize stable negative ion beams for 100 s required in the neutral beam injector of JT-60SA, a physical model to control cesium (Cs) distribution inside the negative ion source has been developed in order to maintain the stable negative ion production at the plasma grid (PG) surface with Cs. In this work, to quantitatively evaluate Cs coverage on the PG, a three-dimensional Cs transportation code was introduced to consider the spatial Cs distribution in the source. The spatial temperature distribution of the chamber wall was also introduced in this model. As a result, the reasonable variation of the Cs coverage for 100 s was obtained, compared to that in the initial model. Based on the modified model, the operational temperature of the chamber wall was proposed to be less than 60 °C to suppress the desorption of Cs in the chamber wall and to sustain the stable negative ion production. In addition, it was also suggested that a slightly higher wall temperature before the operation leads to a decrease in the amount of Cs stored at the chamber wall, resulting in suppression of Cs consumption in the ion source.

Layout optimization of oil-gas gathering and transportation system in constrained three-dimensional space

<p indent=0mm>The layout optimization of oil-gas gathering and transportation system is to minimize the total construction investment of oil-gas pipeline network by using optimization theory. In the process of optimization, it is necessary to collaboratively determine the optimal location and quantity of stations, the connection relationship among the various stations, the path and specification of pipelines. The layout optimization of oil-gas gathering and transportation system is essentially a kind of constrained three-dimensional network topology optimization problem, which belongs to the NP-hard problems in combinatorial optimization. It is of practical significance to solve such problems for reducing the investment of oilfield construction, equivalently enhancing oil recovery and promoting the development of applied optimization theory. However, the existing layout optimization theories and methods of oil-gas gathering and transportation system are mainly for plain oil and gas fields, which could not be applied to the oil and gas fields with undulating terrain. On the basis of accurately characterizing the three-dimensional terrain, it is urgent to establish the optimization model with comprehensive factors and propose the efficient solution methods. In order to deal with the difficulties of seeking the optimal layout of oil-gas pipeline network in spatial scale, such as the huge amount of terrain data, the large number of decision variables and the complex constraints, a series of studies have been carried out. Firstly, from the perspective of generality and comprehensiveness, considering the constraints of random terrain, the layout feasibility of stations, and the gathering and transportation processes, a mathematical model for the layout optimization of oil-gas gathering and transportation systems in the constrained three-dimensional space is established. Secondly, based on digital elevation model (DEM) and weighted digraph in graph theory, the breadth first search algorithm is applied innovatively. Based on the idea of simultaneous search in two opposite directions and the optimality of breadth-first search, the two-way breadth first search algorithm for pipeline path is proposed, and its efficiency is analyzed theoretically. Finally, according to the proposed pipeline path optimization algorithm, the hybrid particle swarm-fireworks optimization (PS-FW) algorithm with global search ability is effectively integrated. By comprehensively applying the PS-FW algorithm and the two-way breadth-first pipeline path search algorithm, the spatial layout of the oil-gas gathering pipeline network and the pipeline path are respectively solved, and the hybrid intelligent optimization method is proposed. According to the convergence theorem of the stochastic optimization algorithm, the global convergence of the hybrid intelligent optimization method is proved. The results show that, compared with the existing theoretical methods, the optimization model established in this paper has more comprehensive consideration and better generality. The proposed two-way breadth-first pipeline path optimization algorithm can save at least 7/9 of the time and space complexity, and improve the solution efficiency significantly. The performance of the hybrid intelligent optimization method is very well, and it can converge to the global optimal solution with probability 1. The optimization model and solution methods proposed in this paper are not only effective for the layout optimization of three-dimensional oil-gas gathering and transportation system, but also have reference value for the multi-level location planning, shortest path, and high-dimensional optimization problems.

A lightweight, low-cost and self-diagnosing mechatronic jaw gripper for the aerial picking with unmanned aerial vehicles

Within recent years the gripping and manipulation of individual objects using unmanned aerial vehicles (UAVs) has become an area of broad scientific research as UAVs allow a fast and three-dimensional transportation of the grasped objects. However, currently there are neither standards for aerial gripping devices nor are there grippers available that are both lightweight and robust enough for the usage with drones and can provide the required feedback on whether the gripping process was successful.In this paper, we therefore present a lightweight, low-cost and self-diagnosing mechatronic jaw gripper for the application with autonomous UAVs. The gripper offers an energy-saving design and an integrated measurement system to detect whether an object was successfully grasped. To evaluate the performance of the gripper it is attached to a quadrotor and tested within different scenarios. The tests include the detection of successfully grasped or dropped out objects and the autonomous pickup and deposit.

HYPERLOOP – The Sustainable Transportation

Due to rapid urbanization and emergence of mega-cities, urban transportation infrastructures are stressed leading to traffic congestion, high fuel consumption as well as increasing number of accidents and fatalities. Present transport sector globally is largely two-dimensional and may not be able to cope up with the growth of cities which is three-dimensional in nature, the environmental pollution, the traffic congestion, the sustainability, etc. This has led to efforts towards three dimensional transportation systems such as passenger drones, flying cars, cars moving through multi-layer underground tunnels etc. The overall concept of three-dimensional transportation demonstrates that the transportation sector has made a significant progress towards comprehending the necessity of a proper and sustainable transit system, which otherwise has implications on environment, health, infrastructure and sustainability as well. However, some of these futuristic options may be associated with safety and security concerns – both for them, as well as caused by them. Some of these options envisage utilization of artificial intelligence and even augmented reality. Technological challenges, the potential for cost-effectiveness, and their socio-economic impacts are also important considerations. Through deep and critical study, in this journal, the author will try to analyze the concept of hyper loop and its practicality; about its various components, its working, global acceptance of hyper loop and its possible advantages and unaddressed issues. Some critics are of the opinion that hyper loop is more of a hypothetical idea which is totally impractical and impossible, but optimistic experts say that it just needs some hard work, a decade’s time and huge amount of money which would then result in revolution of the whole transportation system in a unique, unpredictable and sustainable way. A cross-impact analysis to evaluate possible future scenario for this will also be taken up.

Multi-objective solid transportation problem under stochastic environment

In real life, three-dimensional (solid) transportation problem is an uncertain multi-objective decision-making (MODM) problem. In particular, it involves searching for the best transportation set-up that meets the decision maker’s preferences by considering the conflicting objectives/criteria such as transportation cost, transportation time, environmental and social issues. To tackle such complex situations, this paper proposes a general formulation of the multi-objective solid transportation problem (STP) with some random parameters. The paper makes the following contributions: (i) proposes a solution methodology based on chance-constraint programming technique to solve an STP with the uncertainty characterized by gamma distribution, (ii) proposes the initial feasibility conditions for the problem and (iii) extends fuzzy programming approach for solving the multi-objective stochastic problems. A numerical example is presented to illustrate the model and methodology.

Visualization of integrated energy consumption optimization system for all-weather oil pipeline transportation

Due to the depression of oil pipeline transportation in recent years, the low transportation capacity has become a common situation, and the oil transfer pump unit cannot operate under rated conditions and is in a low efficiency area for a long time. In transportation, throttling is often carried out by adjusting the outlet valve, resulting in a large amount of energy loss. Therefore, in order to reduce the energy loss of the whole oil transportation system, including pumps and pipeline outlet valves, and realize energy saving and emission reduction of oil pipeline transportation, a visual all-weather oil pipeline transportation comprehensive energy consumption optimization system is developed, which includes a pipeline transportation experimental platform, a three-dimensional pipeline transportation virtual scene model, an energy consumption optimization mathematical model, a data display and analysis visual model, and can assist managers in formulating energy saving schemes for pipeline transportation operation and also provide virtual practical services for employee training[1].

Numerical Model of Supersaturated Total Dissolved Gas Dissipation in a Channel with Vegetation

The recent construction and operation of high dams have greatly changed the natural flood process. To meet the ecological demands and flood control requirements of rivers, dams discharge flow through the flood discharge facility, always accompanied by total dissolved gas (TDG) supersaturation in the water, which is harmful to fish. The purpose of this paper is to explore the dissipation characteristics and prediction methods of supersaturated TDG in water flowing through a floodplain covered with vegetation. A three-dimensional two-phase supersaturated TDG transportation and dissipation model considering the effects of vegetation was established. Using existing mechanism experimental results, the inner dissipation coefficient kin of TDG in vegetation-affected flows was studied, and the quantitative relationships between the inner dissipation coefficient kin and the average flow velocity, average water depth, average water radius, Reynolds number, and vegetation density were characterized. Based on the simulation results, the distribution characteristics of the supersaturated TDG in water around vegetation and in the vertical, lateral, and longitudinal directions of the flume under different flow and vegetation densities were analyzed. A supersaturated TDG transportation and dissipation model for vegetation-affected flow is proposed and can be used to predict the impact of TDG in a floodplain.