Space Network System Research Articles

Characteristics of space network system formed by the constituent elements in urban streets: Tianzifang in Shanghai as a case study

ABSTRACT Using a street in Shanghai as a case study, a strategy was developed to study an urban network space system by analyzing and interpreting street space from the microscopic perspective of urban composition elements. At the methodological level, this study, using research methods related to Space Syntax Theory, explored the process of establishing urban elements, element space, and a spatial network system for these elements. The analysis included the integration degree and its distribution (overall infiltration characteristics), the systematic degree, and an adjustment relationship graph for local typical areas. There are three conclusions drawn from the analysis: From the perspective of elements, the Tianzifang street space is annularly connected in circles on different scales and connected in parallel to form an overall spatial structure. At the global level, the distribution of integration degrees exhibits a dotted infiltration pattern from the street to the interior, with a local core. In terms of local and global correlations, spaces with higher traffic attributes tend to increase local and global integration, and spaces with stronger functional attributes tend to increase the separation of local from whole. The element space and its associated shallow space of buildings approximate the overall synergy degree.

Effect of shale diagenesis on pores and storage capacity in the Paleogene Shahejie Formation, Dongying Depression, Bohai Bay Basin, east China

Abstract Compared to other marine-shale gas reservoirs in South China, the shale that developed in faulted basins in East China possesses peculiar characteristics regarding the mineral types and their evolution. The diagenesis of inorganic minerals, generation of hydrocarbons, and evolution of organic matter control the final features and quality of these shale reservoirs. Therefore, we must analyze this diagenesis based on the essential characteristics of the representative reservoir and discuss the influence of the diagenesis' evolution stage on the shale reservoir. This topic is also of practical value for contemporary shale-oil exploration and development. In this paper, we observe diagenesis, study its essential characteristics (such as the structure of the reservoir and pores), determine the key factors that control the reservoir's storage capacity, and analyze the role of diagenesis (organic and inorganic) in the evolution of pores and the reservoir's storage capacity. The mineral types are diverse, and the content of calcite and other carbonate minerals is generally very high. Organic matter is abundant, thermal evolution is low, and the hydrocarbon generation capacity is strong. Because of their high variability, some pores are hard to differentiate from microfractures. Dissolved pores, which are generated by intercrystalline pores and the dissolution of calcite, dolomite, and other carbonate mineral grains, are the major component of a macroporous matrix. The large proportion of hydrocarbons that are generated by solid organic matter leads to the accumulation of pressure. The shale generates a high number of microfractures, which form a reservoir space network system that increases the porosity of the reservoir. Dolomite has a unique supporting role for the matrix pores, leading to the development of a matrix pore-seam system. The reservoir's mineral composition, pore diameter, porosity, and organic-matter content determine the reservoir properties and oil saturation. Organic-rich laminated shale has the best physical properties, dominated by macro-pores and easily connected and merged pore seams. The massive shale has the poorest reservoir property. The development and evolution of pores are mainly controlled by the transformation of clay minerals, the content of carbonate minerals, the sedimentary structure and the intensity of diagenesis. Dissolution depends on the intensity of hydrocarbon generation, the expulsion of acid by organic matter, the state of the carbonate minerals and organic matter, and the smooth depression of the fluid environment. Organic diagenesis is closely related to the diagenesis and evolution of inorganic matter and is typically reflected in the recrystallization of calcite, abundance of organic matter, and hydrocarbon generation by organic matter. A local alkaline diagenetic fluid environment and reduction in the degree of hydrocarbon generation transform incremental porosity to pore reduction. Favorable lithofacies and advantageous layer sections should be selected by considering the stage of diagenesis evolution.

Networking optical antenna of space laser communication

Laser communication network technology has not been broken through and it needs to meet the demands of “high-speed, real-time, dynamic and big range” among platforms, which seriously restricts large-scale engineering application and space network system. To solve the problem of communication platform for networking, a new solution based on rotating parabolic model and a new scheme of laser communication networking antenna system has been put forward in the paper. Depending on the operation mode of the system, multiple mathematical optimization models have been established. Tracking communication range, emission energy efficiency, and receiving energy efficiency have been analyzed and optimized. Relationship among opening up and low apertures, lens unit aperture, focal length of lens unit as well as rotating parabolic focal length have been analyzed. After preliminary optimized design of the system, demand of three satellites in 1000 km, 360° circumferential range, pitch range greater than 20° under the condition of network communication can be reached. Under the background of three LEO (low earth orbit) satellites within 1000 km distance of 2.5 Gbps rate in networking, communication link energy is analyzed and calculated to meet the smallest and the lightest of laser emission energy. Relationship between track angle and receiving as well as emission energy is analyzed. Conclusions can promote various fields of engineering, large-scale applications, and updated generations.

Genetic connection between mud shale lithofacies and shale oil enrichment in Jiyang Depression, Bohai Bay Basin

Abstract By using microscope, argon ion polishing technology, nuclear magnetic resonance (NMR), scanning electron microscopy, and hydrocarbon generation and expulsion simulation, reservoir properties, oiliness and shale oil mobility of different mud shale lithofacies were examined with the mud shale in Jiyang Depression, Bohai Bay Basin as the example. The relationship between lithofacies type and shale oil enrichment was analyzed. Based on the rock composition, sedimentary structures and abundance of organic matter, a mud shale lithofacies classification standard for the upper submember of the 4th Member to the lower submember of the 3rd Member of Paleogene Shahejie Formation (Es4s-Es3x) was established. Six lithofacies are developed in the target formation, in which the laminar organic-rich lithofacies formed in the alternating mechanical transportation deposition and chemical deposition, not only has the highest TOC, S1, oil saturation, movable oil saturation, content of low-carbon light components and oil generation and expulsion rate, but also has various types of reservoir space, abundant pores, and organic network system and interlayer micro-fracture system which can serve as high-speed channels for shale oil and gas migration, so this lithofacies is favorable for shale oil enrichment.

Ensuring Public Realm Through Private- private Partnership, in the Context of Rapid Urbanization (Case of CBD area Kochi)

In the context of rapid urbanization, the lack of public space development is one of the major issues of commercial development in city cores of Kerala. The reasons of this issue are related to land division. In the present context, there are lacks of guidelines to regulate the minimum size of plot during plot subdivision. The individual plot of small size is not feasible for high density commercial development. The land reconstitutions like feasible solutions were adopted by the individual developers to develop large commercial blocks. The public spaces developed as the result of these changes are segregated, introverted and self contained entities like, space inside the commercial malls, shopping centers etc. The intent of this research is to develop the real-estate policies as an urban design tool to create an integrated public space network system in commercial core of the city, and to develop a framework of strategies for the space management models like Private-Private partnership to integrate the existing isolated hybrid spaces in to the city fabric, and to create new integrated system of public space network. A sample precinct of M.G road stretch of Kochi was taken up for demonstration after a detailed analysis of various parameters of open space such as ecology, land use, morphological pattern, and transportation infrastructure.

Characteristics of porosity and permeability layer of fossil Halimeda reef mineral rock of Miocene in the Xisha Islands and its genetic model

Halimeda is one of the major reef-building algas in the middle Miocene of Xisha, and one of the significant reef-building algas in the algal reef oil and gas field of the South China Sea. However, there have been few reports regarding the characteristics of mineral rocks, reservoir porosity and permeability layers, and sedimentation-diagenetic-evolution of fossil Halimeda systems. The present paper briefly introduces the relevant studies on chlorophyta Halimeda and the research status of oil and gas exploration. Through the 1 043 m core of the Xichen-1 well, we studied the characteristics of the mineral rocks and porosity and permeability of the middle Miocene Halimeda of the Yongle Atoll, identified and described the segments of fossil Halimeda, and pointed out that most of the segment slides are vertical sections in ovular, irregular or long strips. The overwhelming majority of these fossil Halimeda found and studied are vertical sections instead of cross sections. In this paper, knowledge regarding the cross sections of fossil Halimeda is reported and proven to be similar with the microscopic characteristics of modern living Halimeda; fossil Halimeda are buried in superposition; it is shown that there are different structures present, including typical bio-segment structure, and due to its feature of coexisting with red alga, tying structure, twining structure and encrusting structure are all present; and finally, it is suggested to classify the fossil Halimeda into segment algal reef dolomites. In addition, all of the studied intervals are moderately dolomitized. Secondary microcrystalline-dolosparite dominates the original aragonite raphide zones, and aphanitic-micrite dolomite plays the leading role in the cortexes and medullas; in the aragonite raphide zones between medulla and cysts, secondary dissolved pores and intercrystalline pores are formed inside the segments, and algal frame holes are formed between segments; therefore, a pore space network system (dissolved pores + intragranular dissolved pores—intercrystalline pores + algal frame holes) is established. Segment Halimeda dolomite has a porosity of 16.2%–46.1%, a permeability of 0.203×10−3–2 641×10−3 μm2, and a throat radius of 23.42–90.43 μm, therefore it is shown to be a good oil and gas reservoir. For the reasons mentioned above, we suggest building the neogene organic reef-modern reef sedimentation-diagenetic-evolution models for the Xisha Islands.

The evolutions of medical building network structure for emerging infectious disease protection and control.

Emerging infectious disease is one of the most minatory threats in modern society. A perfect medical building network system need to be established to protect and control emerging infectious disease. Although in China a preliminary medical building network is already set up with disease control center, the infectious disease hospital, infectious diseases department in general hospital and basic medical institutions, there are still many defects in this system, such as simple structural model, weak interoperability among subsystems, and poor capability of the medical building to adapt to outbreaks of infectious disease. Based on the characteristics of infectious diseases, the whole process of its prevention and control and the comprehensive influence factors, three-dimensional medical architecture network system is proposed as an inevitable trend. In this conception of medical architecture network structure, the evolutions are mentioned, such as from simple network system to multilayer space network system, from static network to dynamic network, and from mechanical network to sustainable network. Ultimately, a more adaptable and corresponsive medical building network system will be established and argued in this paper.

Establishment of spatiotemporal dynamic model for water inrush spreading processes in underground mining operations

Underground mine water inrush accidents are currently one of the most frequent forms of disaster in the mining industry. In order to develop and implement and effective rescue and avoidance plan for water inrush accidents in underground mining projects, this paper proposes a spatiotemporal dynamic three-dimensional (3D) model for the real simulation of the flow spreading process. A spatiotemporal dynamic model framework was developed through an analysis of the factors influencing temporal changes of water inrush spreading in roadways. The basis of the model is the generation of a roadway space network system, the core of the model involves the paths resolving for the water inrush spread processes, and the key of the model consists of the velocity and time resolving for water inrush spread processes. A roadway space network system was generated from roadway data modeling, regularization, arc drift straightening and 3D networking. The result is the spatial illustration of model. A spatial dynamic demonstration model was created with the information gleaned from the resolution of the paths of water spread down as well as water level rising in the roadway space network. A temporal dynamic expression of the model was then created from an examination of the hydraulic characteristics of the water inrush current, and the calculation of the velocity and time of water inrush spread. The feasibility and validity of the spatiotemporal dynamic model for water inrush spread processes was tested and verified through a case study.

Urban green space planning based on computational fluid dynamics model and landscape ecology principle: A case study of Liaoyang City, Northeast China

As a result of environmental degradation, urban green space has become a key issue for urban sustainable development. This paper takes Liaoyang City in Northeast China as an example to develop green space planning using the computational fluid dynamics (CFD) model, landscape ecological principles and Geographical Information System (GIS). Based on the influencing factors of topography, building density and orientation, Shou Mountain, Longding Mountain and the Taizi River were selected as the urban ventilation paths to promote wind and oxygen circulation. Oxygen concentration around the green spaces gradually decreased with wind speed increase and wind direction change. There were obvious negative correlation relationships between the oxygen dispersion concentration and urban layout factors such as the building plot ratio and building density. Comparison with the field measurements found that there was significant correlation relationship between simulated oxygen concentration and field measurements (R 2 = 0.6415, p < 0.001), moreover, simulation precision was higher than 92%, which indicated CFD model was effective for urban oxygen concentration simulation. Only less than 10% areas in Liaoyang City proper needed more green space urgently to improve oxygen concentration, mainly concentrated in Baitai and west Wensheng districts. Based on land- scape ecology principle, green space planning at different spatial scales were proposed to create a green space network system for Liaoyang City, including features such as green wedges, green belts and parks. Totally, about 2012 ha of green space need to be constructed as oxygen sources and ventilation paths. Compared with the current green space pattern, proposed green space planning could improve oxygen concentration obviously. The CFD model and research results in this paper could provide an effective way and theory support for sustainable development of urban green

A Study on the Use of Parks in the Green Matrix System of Kohoku New Town, Japan

This study focuses on the use of parks planned for the open space network system, called the "the Green Matrix System" in Kohoku New Town. The main purpose of the Green Matrix System is to connect parks, communal facilities, and apartment houses with pedestrian and bicycle roads. We investigated the actual condition of park use, with special focus on the combination of parks, and pedestrian and bicycle roads, and in particular their use by pre-school children. We determined the status of use through observational investigation and questionnaire surveys for two areas.The results were, first, that active use was observed by different users for each time period, and that "the extended-pass-type activities" and compound use were observed as a feature of the combination of parks, and pedestrian roads. Second, we conclude that a combination of parks and pedestrian roads strengthens the function of intercommunication and recreation in pass-type activities, and encourages a variety of active uses. On the other hand, it raises safety aspects because of the large amount of bicycles and the strangers passing through the parks, and also because of the numerous blind spots arising because of the plentiful greenery in greenways. There is a possibility that these safety problems could diminish use of the GMS by young children.