Spatial Load Research Articles

Microplastic Mass Concentrations and Distribution in German Bight Waters by Pyrolysis-Gas Chromatography-Mass Spectrometry/Thermochemolysis Reveal Potential Impact of Marine Coatings: Do Ships Leave Skid Marks?

In this first mass-related survey of microplastics (MPs, <1 mm) in the German Bight (North Sea, 2.5 m water depth), spatial load, temporal variations, and potential sources were examined. Relevant plastic types were detected using pyrolysis-gas chromatography-mass spectrometry/thermochemolysis (Py-GC/MS). This suitable method provides qualitative and trace-level polymer or polymer cluster-specific mass quantitative MP data. Neither MP concentration (2-1396 μg m-3) nor type distribution was homogeneous. Concentrations appeared to be substantially influenced by meteorological and oceanographic conditions. The coastal MP-type composition showed an overprint indicating a packaging waste-related signal. Considerably different compositions were observed in central and estuarine areas. Here, a close relation to marine (antifouling) coating particles, i.e., abrased chlorinated rubber-, acryl-styrene-, and epoxide binder-containing particles are hypothesized as the main MP source, indicating ship "skid marks". They represent a dominant, toxicologically relevant but underestimated marine-based MP share, inverting the widely cited 80% terrestrial- to 20% marine-based debris ratio for MPs. In consequence of the findings, polymer clusters attributed to the basic polymers polyethylene, polypropylene, polystyrene, poly(ethylene terephthalate), poly(vinyl chloride), poly(methyl methacrylate), and polycarbonate are proposed for Py-GC/MS MPs mass determination based on specific thermal decomposition products linked to related polymer structural units.

Occurrence of N-nitrosamines and their precursors in the middle and lower reaches of Yangtze River water

The presence of some types of N-nitrosamines in water bodies is of great concern worldwide due to their carcinogenic risks and harmful mutagenic effects on human health. In the present study, eight N-nitrosamines and their formation potentials (FPs) were primarily investigated in Yangtze River surface water to evaluate their spatial distribution, mass loads, and ecological risks. The results showed that of the eight N-nitrosamines investigated, NDMA (<1.5–17 ng/L), NDEA (<1.4–9.5 ng/L), NDPA (1.0 ng/L), NMOR (<1.0–1.3 ng/L), NPIP (<2.1–3.7 ng/L), and NDBA (<3.6–30 ng/L) were detected. The FPs of NDMA (<27–130 ng/L), NDEA (<0.9–2.3 ng/L), NDPA (<1.2–1.9 ng/L), NPYR (<1.4–2.9 ng/L), NMOR (<1.0 ng/L), and NDBA (<1.1–14 ng/L) were significantly identified. NDBA was predominantly observed in surface water, while NDMA was noticeably detected in chloraminated water samples. It was estimated that approximately 5.4 t/y of N-nitrosamines were carried by the Yangtze River to the East China Sea, whereas the input flux of N-nitrosamine precursors was estimated to be approximately 69.5 t/y. Spatial variations were observed due to the input of N-nitrosamines from the upstream dams and lakes. The origin of N-nitrosamine precursors was not associated with the presence of sediment in river water. NDEA could be introduced into river water by the discharge of wastewater. NDBA and its precursors could originate from industrial and aquaculture activities. NDMA and its precursors could result from both of the aforementioned sources. Moreover, the wastewater discharge from small cities, pH value, wastewater treatment ratio, and dilution could be the key factors that influence the occurrence of N-nitrosamines along the Yangtze River. More attention should be paid to the cancer risks posed by N-nitrosamines. The ecological risks posed by N-nitrosamines in the Yangtze River can be ignored.

Incentive-Compatible Demand Response for Spatially Coupled Internet Data Centers in Electricity Markets

An incentive-compatible demand response (DR) strategy is proposed for engaging spatially-coupled Internet data center (IDC) and their spatial load regulation potentials in electricity markets. First, an optimal power flow (OPF) model which considers IDC (referred to as IOPF) is proposed to coordinate IDC DRs and power system operations, in which the formulated IDC load model is compatible with the conventional OPF model. Second, the IOPF-based locational marginal price (LMP) (referred to as ILMP) is derived, which is used to analyze the impact of spatially-coupled DR options on ILMPs and the IDC DR's clearing price. Third, IDC DR activation strategy is proposed as an extension of Net Benefit Test (NBT), where the risk of negative benefit to IDCs is derived. An IDC DR's activation strategy is proposed based on NBT to determine whether non-zero IDC DR dispatches in IOPF are cost-effective. Last, an extra benefit redistribution mechanism is proposed to achieve the incentive-compatibility between social welfare and IDC benefit. The proposed approach is based on the Vickrey-Clarke-Groves mechanism and the contribution factor theory, where the market's revenue adequacy is maintained, and benefits to IDCs and other customers are guaranteed. Simulation results verify the efficiency of the proposed method, implying that the proposed spatially-coupled DRs are compatible with and can enhance existing DR mechanisms.

Internet Data Center Load Modeling for Demand Response Considering the Coupling of Multiple Regulation Methods

The coordination of multiple coupled regulation methods in Internet data centers (IDCs) is proposed in this article to make a full use of IDCs’ spatial and temporal load regulation potentials for demand response (DR). A concise and analytical IDC load model is proposed to facilitate the DR in IDCs. First, the unified IDC load considering multiple coupled regulation methods is modeled represented by workloads and servers. The extra power consumption in IT equipment due to redundancy requirements in computing resources is separated to obtain an explicit mathematical relationship among geo-distributed IDCs. Second, the compatible IDC load model is derived based on a bottom-up approach, where electrical decision variables representing the regulation are introduced to replace non-electrical variables and demonstrate the coupling among multiple regulation methods. Last, a hierarchical control design is deduced to reveal the potentials of the compatible IDC load model in power system applications. Simulations show that the joint implementation of coupled methods can enhance IDC DR capabilities. Simulation results also verify the efficiency of compatible IDC load model in DR and reveal its advantages in load characteristic analyses, computational efficiency, and sensitive information protection of IDCs.

Spatial Load Prediction Considering Spatiotemporal Distribution of Electric Vehicle Charging Load

In view of the influence of large-scale electric vehicle access to the distribution network on spatial load prediction, this paper proposes a spatial load prediction method for urban distribution network considering the spatial and temporal distribution of electric vehicle charging load. Firstly, electric vehicles are classified according to charging mode and travel characteristics of various types of vehicles. Secondly, the probability distribution function is fitted to the travel rules of electric vehicles according to the travel survey and statistical data of residents. Then, the model of electric vehicle travel chain is constructed, and the charging load in different regions and different times is calculated by Monte Carlo method. Finally, based on the actual data of a certain area, the predicted spatial load values of different functional communities in one day are obtained, which can provide reference for future urban distribution network planning.

Spatial Distribution and Load of Per- and Polyfluoroalkyl Substances (Pfass) in Background Soils in Sweden

Spatial Distribution and Load of Per- and Polyfluoroalkyl Substances (Pfass) in Background Soils in Sweden

Spatial Load Migration in a Power System: Concept, Potential and Prospects

As the transmission capability of power systems faces challenges from renewable generation and massive electricity usage, power load resources are playing an increasingly important role in power dispatch. Traditional load dispatch methods are mainly based on the dispatch of load behavior in the time dimension, which has the risk of decreasing the performance of the service provided. In this paper, based on research on space connection usage between power loads, we propose an original concept called spatial load migration (SLM), which provides solutions based on load redistribution and service retainment to address power transmission problems caused by network constraints. With respect to the SLM theme, this paper analyzes the potential of typical power load types participating in SLM, which are organized on a proposed dispatch architecture, and key decision dimensions. The characteristics and dispatch principles of each load type are provided in the form of mathematical models, which are summarized based on the relevant literature. The contribution of this paper is providing an original and practical perspective on power transmission problem solutions. SLM is expected to further improve the flexibility of power load dispatch, which is considered helpful to maintain the efficiency and safety of power systems

Research on Optimization Planning Method of Distribution Network based on Spatial Load Forecast

Power grid planning is an important part in the development of power grid. With the rapid development of urban construction and electricity demand in recent years, electric power construction is faced with more kinds of pressure, such as land resources/environmental protection. In this paper, the difficulty of power grid planning is increasing rapidly. How to build a distribution network that the load and the urban construction can develop concordantly has become a key issue to be solved in the future. The traditional methods of distribution network planning focus on the grasp of the overall, whereas lack adequate consideration of the spatial distribution of load and planning of urban development. Thus, this paper proposes a method based on spatial load forecasting of urban distribution network planning g, and fully considers the load distribution of the space characteristics and urban construction. This method can make up for the defects of traditional methods effectively, thus has certain value and reference significance.

Multi-Stage Distribution Network Space Load Forecasting Method Considering Demand Side Resources

Under the background of the further development of electric power, this paper forecasts the spatial load of distribution network, and proposes a multi-stage spatial load forecasting method considering the demand side resources. Firstly, the load of distribution network is pretreated to improve the prediction function of the processing system, and the working efficiency of the whole system is enhanced to solve the maximum load value. Then, the different conditions of demand side resources are considered step by step to realize the fine analysis, confirm the saturation density value of load, understand the specific information of spatial load, master the predicted data status, and finally carry out the comprehensive prediction method research of spatial load to realize the prediction research of spatial load of distribution network. The experimental results show that the multi-stage spatial load forecasting method considering demand side resources has high accuracy and reliability, and its forecasting effect can improve the system forecasting performance to a certain extent, reduce unnecessary operation time, reduce energy and resource consumption, and promote the development of load forecasting research.

Resolution-Dependent Perspectives on Caribbean Hydro-Climate Change

Near-surface winds around the mountainous Caribbean islands contribute to orographic lifting and thermal diurnal rainfall that requires mesoscale analysis. Here, a new perspective is presented via high-resolution satellite and reanalysis products. Singular value decomposition is applied to 5 km cold-cloud duration satellite data to understand the leading mode of seasonal hydro-climate variability and its regional controls. The spatial loadings reflect wet islands in a dry marine climate, while temporal amplitude is modulated by the large-scale zonal circulation. When summer-time trade winds weaken, daytime confluence around Caribbean islands enlarges, gathering and lifting more moisture. In addition to the static geographic forcing, transient easterly waves impart the majority of marine rainfall between June and September. Higher resolution products capture the thermal orographic effect and reveal upward trends in island rainfall and soil moisture over the satellite era, while lower resolution products miss this effect. The climate of mountainous Caribbean islands is trending toward increased runoff and soil moisture.

Optimisation on plane arrangement of stabilising piles subjected to spatial distributed lateral load in landslides with multilayer sliding masses

The paper develops an analytical method to design the plane arrangement of stabilising piles under spatial lateral load of 3D colluvial landslides with multilayer sliding masses. Firstly, an approach based on the geological map and binary Lagrange Interpolation method was presented to establish 3D landslide calculation models. The improved 3D limit equilibrium method was then proposed to calculate the stability coefficient and spatial distributed lateral load of landslide with multilayer sliding masses. And main sliding direction of 3D multilayer landslide can be determined by the developed principle of minimum potential energy. Moreover, through assuming the piles and soil as elastic transversely isotropic continuum medium, analytical approach was employed to accurately calculate the stress distribution of soil between adjacent piles; and the maximum pile spacing can be calculated. Finally, the reasonable arrangement of stabilising piles can be determined based on Monte-Carlo method and cost of all piles. The finite difference method was employed to validate the theoretical results through the case study of Bazimen landslide. And it is found that the proposed method for the design of piles' arrangement is economically beneficial compared with the traditional method on the premise of ensuring safety.

Spatial Load Forecasting of Urban Power Grid Based on Regulatory Detailed Planning

Spatial load forecasting is a basic work in urban power grid planning. Spatial load forecasting should not only forecast the future load, and the spatial distribution of future load should be provided. Only based on the urban controlled detailed planning, determine the future load of each plot, so as to determine the location and capacity of the substation, model and path of line, the installation of switchgear and its input time and other decision variables, to plan.

Construction and Application of Distribution Network Grid Planning System

For the problems of complex structure, unclear network and fuzzy boundary of power distribution network, grid planning is carried out in the power distribution network according to the idea of “Divide it into small grids, and manage separately”. Firstly, according to the modularization idea and the rule of land use and time development, a three-level grid planning system of power supply functional area, power supply mesh and power supply unit is constructed. Secondly, in the grid planning system, the spatial load forecasting method is given at three levels from bottom to top: at the level of power supply unit, the recommended value of saturated load density index is given, and the calculation method of the simultaneity rate in power supply unit is put forward. At the level of power supply mesh, based on the land nature of each power supply unit, the simultaneity rate of different land is given. Finally, based on the actual planning case of a certain region, the effectiveness of the grid planning method is verified.

Probabilistic Spatial Load Forecasting Based on Hierarchical Trending Method

The efficient spatial load forecasting (SLF) is of high interest for the planning of power distribution networks, mainly in areas with high rates of urbanization. The ever-present spatial error of SLF arises the need for probabilistic assessment of the long-term point forecasts. This paper introduces a probabilistic SLF framework with prediction intervals, which is based on a hierarchical trending method. More specifically, the proposed hierarchical trending method predicts the magnitude of future electric loads, while the planners’ knowledge is used to improve the allocation of future electric loads, as well as to define the year of introduction of new loads. Subsequently, the spatial error is calculated by means of root-mean-squared error along the service territory, based on which the construction of the prediction intervals of the probabilistic forecasting part takes place. The proposed probabilistic SLF is introduced to serve as a decision-making tool for regional planners and distribution network operators. The proposed method is tested on a real-world distribution network located in the region of Attica, Athens, Greece. The findings prove that the proposed method shows high spatial accuracy and reduces the spatial error compared to a business-as-usual approach.

Spatial deformations of osteosynthesis systems. Message 2. Experimental results

Test procedure and a device for the spatial loading of full-scale bone specimens with fractures and fixation means and simultaneous measurement of mutual displacements arising in the fracture region due to the load are presented. The device allows us to apply longitudinal, transverse bending and rotational one-time and long-term cyclic loads to the specimen, simulating the action of loads when walking. The measurement of displacements was carried out by digitally photographing the fracture areas followed by computer image processing.The test results of the “tibia with simulated fracture - fixation plate” systems under spatial loading by three external forces are presented, which cause compression, bending and torsion. As a result of the tests, the values of mutual displacements and the angles of mutual rotation of parts of the fracture were measured.Comparison of test and calculation results using the relationships described in Message 1 shows the suitability of the method, which allows us to quickly and reliably assess the level of displacements in bone fractures under the spatial loading.

Aggregated Model of Data Network for the Provision of Demand Response in Generation and Transmission Expansion Planning

A two-stage Internet data center (IDC)-considered framework in generation and transmission expansion planning (GTEP) (referred to as IGTEP) is proposed to make full use of IDCs’ spatial and chronological load regulation potentials for demand response. Stage one aggregates the data network (DN) to match a transmission network structure. First, IDC load is modeled based on the DN configuration. Second, the aggregated DN (ADN) is proposed to model DN with aggregated front-end servers (FSs) and data flows, where an intuitively accurate mathematical relationship among IDCs is developed. Third, the virtual power network (VPN) is proposed to provide a model for ADN with electrical variables, where the coupling of DN and power network (PN) is proposed to develop a linear aggregated IDC load model. Stage two coordinates IDC DR and GTEP, in which the load coupling among multiple IDCs is managed by VPN and the corresponding IDC load model is compatible with the conventional GTEP load. Simulation results verify the efficiency of the proposed VPN and IDC load model. Simulation results also show that IDC DR may reduce the total IGTEP cost significantly, which implies that DN can play a role equivalent to power lines and generators in power system planning and operations.

Multi‐degree‐of‐freedom force‐displacement mixed control strategy for structural testing

SummaryStructural members carry spatial loads owing to, for example, gravity, winds, and earthquakes. Loads along multiple degrees of freedoms (DOF) should be synchronously imposed on the loading point for accurately reproducing structural responses under spatial loading. Strong coupling may exist among the multiple DOFs owing to specimen rigidity, posing significant challenges for actuator control. Two major problems should be solved to address this challenge. The first is the nonlinear coordinate transformation from the local actuator space (LAS) to the global Cartesian coordinate (GCC) system, depending on the current GCC position of the loading point. The second is the mixed control scheme for engineering specimens, that is, force control in rigid directions and simultaneous displacement control in soft directions, which depends greatly on the nonlinearities developed in specimens. To overcome these difficulties, a modified Newton‐Raphson (NR) iteration integrated with a PI control (MNR‐PI) is developed to handle material nonlinearity, and the incremental kinematic transformation method integrated with PI control (IKT‐PI) is proposed to solve the nonlinear coordinate transformation problem. The theoretical background of the MNR‐PI, which can be synchronously incorporated with the control process of the loading system to solve nonlinear problems, is first provided. The control gains are then designed by discrete control theory, and a new MDOF force‐displacement mixed control method is accordingly formulated and numerically simulated. Finally, three‐DOF cyclic tests on a steel column are conducted to demonstrate the feasibility and accuracy of the proposed method.

Workload management for air-cooled data centers: An energy and exergy based approach

The energy required to cool an air-cooled data center (DC) contributes significantly to the cost of operation, which is further exacerbated due to a poor choice of cooling architecture and ineffective IT workload management. Although existing algorithms reduce energy consumption, they do not minimize thermodynamic irreversibility by design. We provide a tradeoff approach that simultaneously minimizes power usage effectiveness PUE and maximizes the exergy efficiency η2nd. The temperature field is predicted inside a contained single-rack DC that is equipped with a rack-mountable cooling unit (RMCU) based on a mechanical resistance model for the fluid flow. This thermal model informs a multi-objective optimization framework based on a genetic algorithm to determine the optimal decision variables and tradeoffs for PUE and η2nd. We investigate the interrelated effects of (1) guidelines that ensure the reliability of the IT equipment, (2) overall network traffic load, (3) spatial IT load distribution, (4) changes in cooling system variables, and (5) multi-objective optimization. Results for the single rack system are presented in a scalable dimensionless form that is applicable for a multi-rack DC containing RMCUs. By considering the first and second laws of thermodynamics, this novel approach improves workload scheduling from both energy and exergy perspectives.

A spatial finer electric load estimation method based on night-light satellite image

As a fundamental parameter of the electric grid, obtaining spatial electric load distribution is the premise and basis for numerous studies. As a public, world-wide, and spatialized dataset, NPP/VIIRS night-light satellite image has been long used for socio-economic information estimation, including electric consumption, while little attention has been given to the electric load estimation. Additionally, most of the previous studies were performed at a large spatial scale, which could not reflect the electric information inner a city. Therefore, this paper proposes a method to estimate electric load density at a township-level spatial scale based on NPP/VIIRS night-light satellite data. Firstly, we reveal the different fitting relationships between EC (Electric Consumption)-NLS (Night-Light Sum) and EL (Electric Load)-NLI (Night-Light Intensity). Then, we validated the spatial-scale’s influence on the estimation accuracy by experiment via generating a series of simulated datasets. After working out the super-resolution night-light image with the SRCNN (Super-Resolution Convolutional Neural Network) algorithm, we established a finer spatial estimation model. By taking a monthly data of Shanghai as a case study, we validate the model we established. The result shows that estimating electric load at township-level based on night-light satellite data is feasible, and the SRCNN algorithm can improve the performance.

New approach for shear design of reinforced concrete slabs under concentrated loads based on tests and statistical analysis

Despite the international research activity, the shear strength of reinforced concrete slabs without shear reinforcement is not yet satisfactorily resolved. In particular, deck slabs of existing bridges often show significant deficits in design shear capacity, although no damage has been reported so far. A test series of 14 large-scale cantilever slabs subjected to concentrated loads was conducted and analysed at the Hamburg University of Technology. Varying the distance between the concentrated load and the support in a previously unexamined wide range led to new considerations regarding the shear capacity in RC slabs.The ultimate and residual loads of the test specimens, as in many other studies on this topic, clearly exceeded the values for vehicle load assumptions in the current standards. In contrast to previous studies, a large shear slenderness in the load arrangement could be realized in the tests. This was the basic requirement for one of the key findings: The critical shear crack occurs locally in the area of load application and not at the support. Thus, shifting the design section for shear close to the concentrated load is reasonable, while in many approaches a critical section close to the support is chosen. Furthermore, the often-used effective width beff, which depends on the distance of single loads to the support, does not seem justified. The shear forces should be determined by finite element analysis, a common method in practice, which can consider the spatial load transfer and the stiffness of the support in a realistic manner.The new design method presented here is therefore not primarily concerned with the shear resistance, as other investigations are, but first on the side of determining the relevant internal shear forces, which are initially higher in the design section proposed here. Only in a second step is a preliminary factor C*Rd,c for the calculated resistance determined by means of a well-founded statistical evaluation. For this purpose, a database with 45 tests on RC slabs has been established. The new design approach provides significant greater shear capacities than the current regulations.