bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation of new waves in chemical engineering
Authors: Abdelrahman Mahmoud A E , Refaey H A , Alharthi Mathkar A
Published: April 2021

Modelling of wave motion and propagation characteristics of waves is of great significant in chemical engineering. Waves are the major source of chemical actions in various real life applications. We apply an efficacious solver to give exact traveling wave solutions of the Hirota-maccari model. This solver introduces closed-form wave structures of the solutions. The traveling wave solutions are expressed by hyperbolic function solutions. These solutions may be applicable for some real life problems in chemical engineering, biological engineering, plasma physics and etc. Some two and three dimensional graphics are plotted for certain parameter values to describe the propagation of traveling wave solutions. Finally, it is pondered that the proposed approach can also be applied to another sort of complex models.
Phase structures and transitions of quintessence surrounding RN black holes in a grand canonical ensemble *
Authors: Huang Yuchen , Jing Hongmei , Tao Jun , Yao Feiyu
Published: April 2021

Considering a grand canonical ensemble, we study the phase structures and transitions of RN black holes surrounded by quintessence dark energy on two different boundary conditions, namely AdS space and a Dirichlet wall. For AdS space, under the condition of fixed temperature and potential, as the temperature increases for lower potential, the black hole undergoes a first-order phase transition, while for higher potential, no phase transition occurs. There are two different regions in the parameter space. For the Dirichlet wall, on which the temperature and potential are fixed, the state parameter of quintessence

is analyzed in detail. Then, three different physically allowed regions in the parameter space of the black hole are well studied. As the temperature rises, first-order and second-order phase transitions may occur. In this case, there are nine regions in the parameter space, which is evidently distinct from the case of AdS space.
Coexistence of isospin I = 0 and I = 1 pairings in asymmetric nuclear matter *
Authors: Yan Yi-Jun , Shang Xin-Le , Dong Jian-Min , Zuo Wei
Published: April 2021

The coexistence of neutron-neutron (n-n), proton-proton (p-p), and neutron-proton (n-p) pairings is investigated by adopting an effective density-dependent contact pairing potential. These three types of pairings can coexist only if the n-p pairing is stronger than the n-n and p-p pairings for the isospin asymmetric nuclear matter. In addition, the existence of n-n and p-p pairs might enhance n-p pairings in asymmetric nuclear matter when the n-p pairing strength is significantly stronger than the n-n and p-p ones. Conversely, the n-p pairing is reduced by the n-n and p-p pairs when the n-p pairing interaction approaches n-n and p-p pairings.
Transcranial photobiomodulation changes topology, synchronizability, and complexity of resting state brain networks
Authors: Ghaderi Amir Hossein , Jahan Ali , Akrami Fatemeh , Moghadam Salimi Maryam
Published: April 2021

Objective. Transcranial photobiomodulation (tPBM) is a recently proposed non-invasive brain stimulation approach with various effects on the nervous system from the cells to the whole brain networks. Specially in the neural network level, tPBM can alter the topology and synchronizability of functional brain networks. However, the functional properties of the neural networks after tPBM are still poorly clarified. Approach. Here, we employed electroencephalography and different methods (conventional and spectral) in the graph theory analysis to track the significant effects of tPBM on the resting state brain networks. The non-parametric statistical analysis showed that just one short-term tPBM session over right medial frontal pole can significantly change both topological (i.e. clustering coefficient, global efficiency, local efficiency, eigenvector centrality) and dynamical (i.e. energy, largest eigenvalue, and entropy) features of resting state brain networks. Main results. The topological results revealed that tPBM can reduce local processing, centrality, and laterality. Furthermore, the increased centrality of central electrode was observed. Significance. These results suggested that tPBM can alter topology of resting state brain network to facilitate the neural information processing. On the other hand, the dynamical results showed that tPBM reduced stability of synchronizability and increased complexity in the resting state brain networks. These effects can be considered in association with the increased complexity of connectivity patterns among brain regions and the enhanced information propagation in the resting state brain networks. Overall, both topological and dynamical features of brain networks suggest that although tPBM decreases local processing (especially in the right hemisphere) and disrupts synchronizability of network, but it can increase the level of information transferring and processing in the brain network.
Benchmark of quasi-linear models against gyrokinetic single scale simulations in deuterium and tritium plasmas for a JET high beta hybrid discharge
Authors: Mariani A. , Mantica P. , Casiraghi I. , Citrin J. , Görler T. , Staebler G.M. , JET1 contributors EUROfusion
Published: April 2021

A benchmark of the reduced quasi-linear models QuaLiKiz and TGLF with GENE gyrokinetic simulations has been performed for parameters corresponding to a JET high performance hybrid pulse in deuterium. Given the importance of the study of such advanced scenarios in view of ITER and DEMO operations, the dependence of the transport on the ion isotope mass has also been assessed, by repeating the benchmark changing the ion isotope to tritium. TGLF agrees better with GENE on the linear spectra and the flux levels. However, concerning the isotope dependence, only QuaLiKiz reproduces the GENE radial trend of a basically gyro-Bohm (gB) scaling at inner radii and instead anti-gB at outer radii. The physics effects which are responsible of the antigB effect in GENE simulations have been singled out.
The role of 3D fields on runaway electron mitigation in ASDEX Upgrade: a numerical test particle approach
Authors: Gobbin M. , Marrelli L. , Valisa M. , Li L. , Liu Y.Q. , Papp G. , Pautasso G. , McCarthy P.J. , Upgrade Team the ASDEX , MST1 Team the EUROfusion
Published: April 2021

The data collected during ASDEX Upgrade experiments in which external 3D fields have been deployed in the attempt of mitigating runaway electrons (RE) are interpreted by a numerical test particle approach. To this end the Hamiltonian guiding center code ORBIT has been used, with the implementation of the magnetic perturbation spectrum modeled by the code MARS-F, which also takes into account the plasma response to the applied 3D fields. In agreement with the observed phenomenology, ORBIT simulations show that the configuration of the currents in the top/bottom arrays of error field coils, which maximizes the plasma response to the external perturbations, is the one that most affects the high energy test electron trajectories in the edge region, thus leading to an enhancement of the energetic electron losses. This occurs in particular during the disruption, i.e. taking into account the increased toroidal electric field associated with the fast plasma cooling. Used in a predictive way, the numerical results suggest which coil configuration could further improve the RE mitigation.
Retraction: The A Satellite-to-Ground Quantum Key Distribution Protocol Based on Orbital Angular Momentum of Light (J. Phys.: Conf. Ser.
1757 012173)
Authors: Wang Sheng , Lin Yu , Ye Xun , Zhang Tianbing , Feng Bao , Yu Xiang Bian
Published: April 2021

IOP Publishing Limited ("IOPP") is retracting this paper following an investigation which has confirmed this work has significant overlap with a preprint written by another author group, without permission or acknowledgement to the original authors. IOP Publishing Limited request any citations to this article be redirected to the original work [1].

IOPP have made multiple attempts to contact the author but has not received a response. The author is encouraged to contact jpconf@ioppublishing.org.

[1] Wang Z, Malaney R and Burnett B 2020 https://arxiv.org/abs/2007.07748

Retraction published: 23 April 2021
Organic optical agents for image-guided combined cancer therapy
Authors: Gao Zhiyuan , Li Cong , Shen Jing , Ding Dan
Published: April 2021

As a promising non-invasive treatment method, phototherapy has attracted extensive attention in the field of combined cancer therapy. Among various optical agents, organic ones have been considered as a promising clinical phototheranostic agent due to its high safety and non-toxic property. In addition, due to the clear structure, facile processability, organic optical agents can be easily endowed with multiple imaging and phototherapeutic functions, significantly simplifying the relatively complex system of imaging-guided combined cancer therapy. This review summarizes the recent research on organic optical agents in imaging-guided combined cancer therapy. The application of organic optical agents in a variety of combined cancer therapeutic modes guided by imaging are introduced respectively, including photodynamic and photothermal combined therapy, phototherapy-combined cancer chemotherapy, and phototherapy-combined cancer immunotherapy. Finally, the concluding remarks and the future prospects are discussed.
Hydrogel from acellular porcine adipose tissue promotes survival of adipose tissue transplantation
Authors: Liu Peng-Cheng , Tan Qiu-Wen , Zhang Yi , Wang Hua , Zhou Li , Yang Qian-Ru , Xu Li , He Tao , Xie Hui-Qi , Lv Qing
Published: April 2021

Lipofilling is a popular technique for soft tissue augmentation, limited by unpredictable graft survival. This study aimed at exploring the effect of hydrogel from acellular porcine adipose tissue (HAPA) on angiogenesis and survival of adipose tissue used for lipofilling. The effect of HAPA on adipose-derived stem cells (ADSCs) proliferation, adipogenic differentiation, and vascular endothelial growth factor (VEGF) secretion were evaluated in hypoxia and normoxia in vitro. For the in vivo study, adipose tissue with phosphate buffered saline, ADSCs, and HAPA (with or without ADSCs) were co-injected subcutaneously into nude mice. HAPA–ADSCs mixture (tissue engineering adipose tissue) was also grafted. Gross observation, volume measurement, and ultrasound observation were assessed. For histological assessment, hematoxylin and eosin, perilipin, cluster of differentiation 31 (CD31), Ki67, and transferase-mediated d-UTP nick end labelling (TUNEL) staining were performed. HAPA improved ADSCs proliferation, VEGF secretion, and adipogenic differentiation under normoxia and hypoxia conditions in vitro study. For the in vivo study, HAPA showed improved volume retention and angiogenesis, and reduced cell apoptosis when compared to ADSCs-assisted lipofilling and pure lipofilling. In conclusion, HAPA could maintain ADSCs viability and improve cell resistant to hypoxia and might be a promising biomaterial to assist lipofilling.
Remote sensing of lake ice phenology in Alaska
Authors: Zhang Shuai , Pavelsky Tamlin M , Arp Christopher D , Yang Xiao
Published: April 2021

The timing of lake ice breakup and freezeup are important indicators of climate change in Arctic and boreal regions because they respond rapidly and directly to variations in climate conditions. Despite its importance, lake ice phenology remains poorly documented in most lakes of Alaska. To fill this data gap, we constructed a remote sensing-derived lake ice phenology database covering all lakes in Alaska larger than 1 km2 (n = 4241) over the period 2000–2019. This dataset, which includes lake ice on/off dates and lake ice duration, was based on an automatic method using daily moderate resolution imaging spectroradiomenter (MODIS) imagery to measure lake ice fraction. This method extracts lake ice pixels from MODIS images using a dynamic threshold that was calibrated against Landsat Fmask. Different filters that account for clouds, polar night, and other sources of error were applied to increase the accuracy of lake ice phenology estimation. Trend analysis shows earlier breakup (−5.5 d decade−1) for 440 lakes and later breakup (7.5 d decade−1) for four lakes (p < 0.05). A total of 289 lakes had significant trends toward later freezeup (2.9 d decade−1) and 11 lakes towards earlier freezeup (−3.3 d decade−1). Most lakes with significant trends are north of the Brooks Range. This dataset can contribute to increased understanding of interactions between lake processes and climate change, and it supports the study of biogeochemical, limnological and ecological regimes in Alaska and pan-Arctic regions.
Years of life lost and life expectancy attributable to ambient temperature: a time series study in 93 Chinese cities
Authors: Ai Siqi , Qi Jinlei , Liu Jiangmei , Wang Lijun , Yin Peng , Li Ruiyun , Wang Chongjian , Lin Hualiang , Zhou Maigeng
Published: April 2021

Although increasing evidence has reported that unfavorable temperature may lead to increased premature mortality, a systematic assessment is lacking on the impact of ambient temperature on years of life lost (YLL) and life expectancy in China. Daily data on mortality, YLL, meteorological factors and air pollution were obtained from 93 Chinese cities during 2013–2016. A two-stage analytic approach was applied for statistical analysis. At the first stage, a distributed lag non-linear model with a Gaussian link was used to estimate the city-specific association between ambient temperature and YLLs. At the second stage, a meta-analysis was used to obtain the effect estimates at regional and national levels. We further estimated the corresponding YLLs and average life expectancy loss per deceased person attributable to the non-optimum temperature exposures based on the established associations. We observed ‘U’ or ‘J’ shaped associations between daily temperature and YLL. The heat effect appeared on the current day and lasted for only a few days, while the cold effect appeared a few days later and lasted for longer. In general, 6.90% (95% confidence interval (CI): 4.62%, 9.18%) of YLLs could be attributed to non-optimum temperatures at the national level, with differences across different regions, ranging from 5.36% (95% CI: −3.36%, 6.89%) in east region to 9.09% (95% CI: −5.55%, 23.73%) in northwest region. For each deceased person, we estimated that non-optimum temperature could cause a national-averaged 1.02 years (95% CI: 0.68, 1.36) of life loss, with a significantly higher effect due to cold exposure (0.89, 95% CI: 0.59, 1.19) than that of hot exposure (0.13, 95% CI: 0.09, 0.16). This national study provides evidence that both cold and hot weather might result in significant YLL and lower life expectancy. Regional adaptive policies and interventions should be considered to reduce the mortality burden associated with the non-optimum temperature exposures.
The energy and carbon inequality corridor for a 1.5 °C compatible and just Europe
Authors: Jaccard Ingram S , Pichler Peter-Paul , Többen Johannes , Weisz Helga
Published: April 2021

The call for a decent life for all within planetary limits poses a dual challenge: provide all people with the essential resources needed to live well and, collectively, not exceed the source and sink capacity of the biosphere to sustain human societies. We examine the corridor of possible distributions of household energy and carbon footprints that satisfy both minimum energy use for a decent life and available energy supply compatible with the 1.5 °C target in 2050. We estimated household energy and carbon footprints for expenditure deciles for 28 European countries in 2015 by combining data from national household budget surveys with the environmentally-extended multi-regional input–output model EXIOBASE. We found a top-to-bottom decile ratio (90:10) of 7.2 for expenditure, 3.1 for net energy and 2.6 for carbon. The lower inequality of energy and carbon footprints is largely attributable to inefficient energy and heating technologies in the lower deciles (mostly Eastern Europe). Adopting best technology across Europe would save 11 EJ of net energy annually, but increase environmental footprint inequality. With such inequality, both targets can only be met through the use of CCS, large efficiency improvements, and an extremely low minimum final energy use of 28 GJ per adult equivalent. Assuming a more realistic minimum energy use of about 55 GJ ae−1 and no CCS deployment, the 1.5 °C target can only be achieved at near full equality. We conclude that achieving both stated goals is an immense and widely underestimated challenge, the successful management of which requires far greater room for maneuver in monetary and fiscal terms than is reflected in the current European political discourse.
Initiatives for Formation and Effective Utilization of Underground Pedestrian Networks in Japan
Authors: Tsui Yuji Tsu , Ikeda Keigo , Kita Keigo
Published: April 2021

In recent years, cities in Japan have faced a strong demand for improving urban environment and securing disaster prevention functions in response to changes in the socio-economic situation such as rapid development of information technologies, globalization, declining birthrate and aging population. In this context, underground pedestrian networks has not only the purpose of alleviating chronic congestion aboveground, but is expected to play various roles such as improvement of convenience by directly connecting to offices and commercial facilities, and provision of temporary occupancy function in the event of a disaster. Furthermore, it is possible to promote sophistication of underground space and to enhance various functions as a city, and efforts for implementation have already started. This paper introduces examples of underground pedestrian network projects that are being implemented in line with urban renewal, as well as efforts on effective utilization of underground space with new technologies in major cities in Japan.
A Feasibility Study of Urban Underground Logistics System -- A Case Study of Shanghai
Authors: Lu B , Zhang M X , Fan Y Q
Published: April 2021

With rapid development of e-commerce, new retail and other new Internet business models, the requirements of the higher package handling efficiency and lower delivery cost are put forward in logistics industry. However, due to the lack of logistics facilities, the limitation of ground roads and the land use, the service of express delivery cannot satisfy the logistics demand, which makes the express delivery a “bottleneck” that restricts the development of urban logistics. Underground Logistics System (ULS) can be a new way to handle it. ULS refers to a logistics system which uses specific vehicles to realize the seamless connection of automatic loading, unloading, transportation, sorting and delivery of goods in the underground based on information technology. Firstly, we have studied ULS and explored its system architecture and advantages. Then, we have combined it with Shanghai Master Plan 2017-2035 and its express facilities planning, and provided a forecast of the express delivery demands in Shanghai in 2035. Based on the findings, we have proven the necessity of ULS corridors in the city. It is likely that the increase of logistics demand will bring about some urban problems such as traffic congestion, environmental pollution and resource waste, if no timely action is taken. As a new mode of urban express delivery, ULS can reduce the above negative effects and promote the sustainable development of the city.
An Exploration of the Planning Approach for New Development Area with Underground Space in Hong Kong
Authors: Law K , Ng F , Kwan J , Wong J
Published: April 2021

Hong Kong is a densely populated city. Development of New Town or more recently called New Development Area (“NDA”) has been adopted to create more space for housing, working places and community facilities in the last few decades. But till now the planning of NDA remains focusing on above ground intervention without consideration in making use of underground strata and the opportunities for underground space development as a major land asset have not been fully explored. Whenever the potential use of underground spaces would arise, they are usually found to conflict with the established surface land development and difficult to be pursued.

With the public aspiration for better living and working environment, the demand for enhanced utilization of underground strata as one of the spatial solutions is ever increasing in Hong Kong. As a response, underground space is now considered by a government appointed task force as one of the medium-to-long term options in increasing land supply. This paper will endeavour to propose an integrated approach of land use planning incorporating underground space for the future NDA planning, drawing on the experiences from recent plans and projects in other cities.
Mapping subsurface qualities for planning purposes: a pilot study
Authors: Norrman J , Ericsson L O , Nilsson K L , Volchko Y , Sjöholm J , Markstedt A , Svahn V
Published: April 2021

The subsurface can be used for a variety of purposes in the urban environment and the subsurface should ultimately be seen as a multifunctional resource, offering a multitude of benefits to humans and the society. Underground construction is commonly planned according to the first come, first served principle and later claims on other resources in the subsurface will have to adapt, often at high costs, or are made impossible. This pilot study is a first step in developing a method aiming to investigate a procedure for mapping an area’s subsurface resources, having the multifunctionality of the subsurface in mind, and integrating this information into urban planning processes. A mapping of the existing resources (supporting, provisioning, regulating, cultural) used at present and their future potential is presented, and an analysis, using an interaction matrix, of how the different subsurface resources can influence each other (conflicts and synergies) if the use(s) changes. Conclusions are that: 1) the concept of geosystem services can strongly support the communication about the subsurface between civil/geotechnical engineers and planners; 2) there is a need at the municipality or city level for systematised and digital 3D archives for easy access to information in relevant format; 3) planning based on the perspective that the subsurface has multiple resources, makes subsurface planning not only a metropolitan issue but also relevant for smaller municipalities. Further work is suggested to: i) explore the concept of geosystem services in a planning context; ii) suggest at which planning level different geosystem services can be optimally managed; and iii) develop tools to support planners for handling subsurface conflicts and acknowledge synergies.
Evaluation of Spatial Performance of Urban Underground Public Space: A Case Study of Wujiaochang Sub-center in Shanghai
Authors: Ma Chen-Xiao , Peng Fang-Le , Zhang Jun-Bo , Wang Tian-Qing
Published: April 2021

Urban underground public space (UUPS) creates extra open space for local citizens, increases neighborhood vibrancy and improves the walkability of local blocks. Recently, huge amounts of UUPS have been built in Shanghai with the rapid development of metro systems. Among them, construction of UUPS in Wujiaochang Sub-center has achieved a great success in spatial performance with a systematic planning and implementation for more than 15 years. This paper proposes a comprehensive evaluation method for UUPS with 7 quantitative indices to assess the spatial performance in the aspects of social development, spatial structure development and traffic development. Evaluation results indicate that the UUPS in Wujiaochang Sub-center provides efficient public space for diverse activities to improve local vitality, improves urban compactness and dramatically increases the local pedestrian network efficiency and metro service scope. The study hopes to provide insights of a better UUPS planning and constructive suggestions for the future.
The implementation of network governance for sustainable urban underground usage, a comparative analysis of the case studies of the cities of Rio de Janeiro, Brazil and Helsinki, Finland.
Authors: de M Raposo Luís Carlos M M
Published: April 2021

This research investigates how cities faced with the intensification of underground space usage to accommodate urban infrastructure are being required to change their traditional method of planning and management of underground space use. The shift is represented by the replacement of an uncoordinated approach to new forms of planning and management that respects the multiple interactions between stakeholders and takes into consideration the multiple relationships that are created with urban underground usage. The study works with the hypothesis that there is a need for a special form of governance of this layer that may contribute to the capacity of continuance of underground space usage for present and future generations, thus contributing for urban sustainability. Two case studies are developed to verify how the concepts are reflected in these cities’ lives and to compare the choices made by cities’ administrations, presenting their similarities or differences in order to assess how different initiatives may behave in different contexts. These case studies are theHelsinki Underground Master Plan-UMP, one of the world’s most comprehensive and advanced urban underground planning instrument and the Rio de Janeiro’sProjectGeoviasan initiative designed to map and register under one single database all the underground infrastructure existent in the urban area. aimed to make possible a more efficient arrangement of the city’s underground. The research suggests that the implementation of network governance tools centered on coordination and guidance of interactions and relationships according to shared objectives are examples of operational models of urban governance that modify the way cities plan and manage underground space usage more capable to provide the continuance of underground uses into the future what may be considered as a contribution for urban sustainability as most of these uses are vital for the satisfaction of the city’s essential needs.
Renovation mode for growing underground pedestrian system within station area: a case study of Shanghai Jing’an Temple Station
Authors: Zhang Z Y , Ma C X , Peng F L
Published: April 2021

The underground pedestrian system within Jing’an Temple Station area in Shanghai provides convenience for local pedestrians and promotes the compact development of surrounding urban area by building connections between the metro station and surrounding underground public spaces. On the other hand, deserted spaces and congested spaces still exist in this system. In this paper, based on the space syntax methodology, we first study the spatial configuration of this pedestrian system by conducting segment analysis. It is found that the system is roughly in a radial shape, with concentrated traffic pressure on the core and low accessibility on each end. Renovation alternatives are then developed towards those defects. By analyzing and comparing topological features, such as spatial configuration, accessibility and transit activity, among renovation alternatives, a renovating mode of the growing underground pedestrian system within station area is put forward that small walkable ringways are constructed successively and weaved into an underground walking network.
Re-promoting Sustainable Underground Urbanization for Developed and Developing Countries in Our Modern History
Authors: Li Amy Huanqing
Published: April 2021

During recent decades of overwhelming exploration of underground resources (groundwater, geothermal energy, minerals) and underground spaces (tunnels, caverns, buildings), there has been a lack of in-deep investigation on international agenda to look at the degree of political awareness of sustainable underground development. International organizations advocating and debating the use of underground space and its innovative contribution to urban futures, have been sustained through intensive interaction through conferences and working groups. These active moves involved public and private actors from developed and developing countries, with a rapidly increasing interest to explore the various and viable usage of this natural resource – subsurface space. From 2014 to present, as an international consensus built up by a long-term advocating efforts addressed through a series of World Urban Forums, United Nations Human Settlements Program (UN-HABITAT) recognized the necessity of promoting best practices of the sustainable use of underground space for resilient urban development in modern era and for implementing the 17 Sustainable Development Goals (SDGs) of UN 2030 Agenda. This article will present a first retrospect on the modern history of research initiation and international promotional agenda for sustainable underground urbanization. Qualitative archive data analysis and city case study demonstration will be used to showcase international stakeholders’ awareness enhancement, policy promotion and universal implementation.
Study on Planning of New Underground Railway & New Station in The Yaesu-Kyobashi-Nihonbashi District (Part 2)
Authors: Ohmura Satoshi , Asano Hitoshi , Yokotsuka Masami
Published: April 2021

The Urban Underground Space Center of Japan (USJ), composed of public, private and academic sectors, aims at utilizing urban underground space through various activities like research, study etc. This paper is the second report of the Yaesu-Kyobashi-Nihonbashi Committee USJ’s Three - year project on planning of new underground railway station supposed to be constructed near Tokyo Station once the railway network is to be realized, connecting Tsukuba and Haneda Airport and running through near Tokyo Station, Tokyo Bay Area etc. This research is vital for Yaesu-Kyobashi-Nihonbashi district as many redevelopment projects are carried out vigorously in conjunction with sharp increase in the volume of passenger traffic passing this district.

This time, we mainly report the purpose and role of new underground railway, and the comparative study of route plans. The route plans of A, B and C are compared in terms of the three elements – construction costs, accessibility to the existing Tokyo Station and contribution to revitalization of the district.

As a result of the study, it was suggested that it would be desirable to build a new underground railway under the Chuo-dori street from the viewpoint of town development of this district.
Moving underground for urban regeneration – Design challenges and cost assessment for the proposed undergrounding of Poseidonos av.
Authors: Poulidi N , Benardos A
Published: April 2021

The evolution in underground construction has led to the development of many large-scale underground projects in which essential infrastructure are placed, and though this facilitating the preservation or even the reclamation of valuable surface space. A part of these underground structures is the subsurface transformation of road networks, aiming either at the better traffic regulation, or at the rehabilitation of the surface urban setting. However, special design requirements are needed along with the accurate costing of the proposed solution that would finally assess the feasibility of the project. The paper deals with the proposed underground relocation of a section of the Poseidonos av., a major coastal highway in Athens, as part of the greater urban regeneration that is going to take place in the Hellinikon area. The design of the 1.47 km underground section is proposed to be implemented as a cut-and-cover top down development that will inflict minimal traffic intervention during construction. Also, all proposed surface arrangements and configurations are presented, designed to ensure efficient transit to all users of the road and the surface area. Finally, the design details are used to draw accurate assessments of the required cost and time of the project that will completely transform the area and actually further boost the integration of the Hellinikon development project in the surrounding area.
The design and construction of a large composite subway station in limited space: An exemplary application of OCUE method in Xuzhou, China
Authors: He Junzuo , Liao Shaoming , Gong Zhiqun , Tang Cong , Liu Mengbo , Li Yang
Published: April 2021

Due to the compact space and high utilization demands, the construction of large underground subway transfer station in urban area, like Pengcheng Square station in Xuzhou, China, was confronted with various obstacles, such as nearby surface and subsurface structures, heavy road traffic, and clay-rock mixed ground conditions. Based on careful investigations to all surrounding limitations, an innovative composite station form and its corresponding construction method, open cutting with underground excavation (OCUE) method, were introduced. The construction performance of this method has been confirmed by field monitoring. The main findings from the research include: (1) Sophisticated design and construction is essential for satisfying the expected functions of the station, minimizing the influence on the heavy traffic and sensitive structures in adjacent, as well as tackling the adversities of the clay-rock mixed strata; (2) Supported by the OCUE method, composite form of subway station was delicately designed to maximize the utilization of limited space, it comprised of open cutting part, underground excavation part and half-covered excavation part; (3) The implementation of OCUE method was successful with little influence on the surrounding traffic and buildings. Experiences obtained from this project can provide effective reference for similar cases.
Development of urban public spaces using urban underground spaces: a new method to improve quality of life (QOL) in Tehran metropolis
Authors: Safaee Mohammad Mahdi , Nematipour Narges
Published: April 2021

Once Tehran was an enchanting city garden with abundant green lands at Alborz mountain range. Now it has changed into a metropolis with many problems as a result of losing a lot of gardens, farms, and green spaces. Tehran is the capital of Iran with a population around 13 million people daytime and 8.5 million people night-time. Its area is about 730 square kilometres and in terms of population density, it is ranked 25th in the list of most populous cities. Due to the lack of public spaces required, Tehran metropolis has faced serious challenges to create a sense of life satisfaction in the residents. Due to population density and numerous amount of mass housing and high land prices, the development of public spaces required by the city has become more difficult. Therefore, one of the ways to develop such spaces is to use underground surfaces and combine them with existing surfaces on the ground. How to properly correlate and interact between the development of urban public spaces, urban underground spaces and improving Tehran metropolis citizens’ quality of life and provide solutions for it, is the main issue of this research.
Integration of 3D models of structures and geological composition as an underground infrastructure model
Authors: Hakoda Toshiaki , Nishiyama Syoichi , Omori Takaki , Okumura Tadahiko , Narusawa Mamoru , Yabuki Nobuyoshi
Published: April 2021

To develop three-dimensional (3D) models as examples of the infrastructure model concept which would be useful for the operation and maintenance or design and construction of underground facilities we integrated 3D models of the geological composition, the structure and the lifeline facilities (water supply and sewerage system, city gas line, electrical power and communication lines) for the underground mall named ESCA in Nagoya City, Japan. In addition to the above 3D models, 3D structural models of tunnels of the underground railway passing underneath ESCA are developed based on as-built drawings in cooperation with the transportation authority of Nagoya City, and settlements occurred by that construction are visualized in 3D models from a record of the construction of tunnels of that subway. ESCA built out a 3D data platform with browser software for daily maintenance and planning of modification work of the underground mall.
Study on the distribution of sulfur-bearing formations in the Sichuan Basin and its damage to tunnel engineering
Authors: Su Peidong , Zhao Yi , Xu Zhengxuan , Du Yuben , Qiu Peng , Wang Dong , Li Yougui
Published: April 2021

The sulfur-bearing formations in the Sichuan Basin are widely distributed, whose harmful gases have caused serious threat to tunnel engineering. Based on the existing data collected, the research shows that the main sulfur-bearing formations in the Sichuan Basin include the Triassic Leikoupo Formation, Jialingjiang Formation, and Feixianguan Formation, the Permian Longtan Formation, the Carboniferous Huanglong Formation, the Silurian, the Cambrian and the Sinian. Sulfur-containing gas is closely related to the active degree of tectonic movement in the area where it is located, and is mainly manifested in three aspects: the generation, migration and storage of sulfur-containing gas. According to the tectonic distribution, depth and concentration of the Sichuan basin, the hazard grade of the sulfur-bearing strata in the basin was classified. The Permian Longtan Formation and the Carboniferous Huanglong Formation can be divided into Level IV sulfur-containing strata. The Triassic Leikoupo Formation, Jialingjiang Formation, Feixianguan Formation, and the Silurian strata can be divided into Level III sulfur-containing strata, meanwhile the Cambrian and Sinian strata can be divided into Grade II. The result of sulphur-bearing strata hazard classification was applied to the Yuelongmen Tunnel of Chenglan Railway, and the on-site inspection results were consistent with the application analysis results.
Cost benefit analysis of the Athens metro line 3 expansion project
Authors: Sourouvali N , Benardos A , Mavrikos A
Published: April 2021

Metro projects have become an essential infrastructure of modern large metropolitan areas worldwide, as they provide fast, reliable and efficient transportation services, promoting overall mobility, environmental stewardship and economic vitality. In order to assist the decision-making process of pursuing such high cost underground infrastructure, its assessment should not only be based in a purely financial evaluation. On the contrary, the implementation of a comprehensive social cost-benefit analysis incorporating the monetary values of the environmental and social benefits of underground transit systems is an important element to highlight latent qualities. The paper presents an ex-post cost benefit analysis focusing on the last segment of the Athens metro line 3 expansion, from Egaleo to Ag. Marina station. This section has been developed from 2007 and was put in service in 2014. The analysis incorporates actual cost figures from the construction period as well as the operational cost of the segment during the first years of operation. The project is assessed on the grounds of an investment plan using the social NPV and social IRR criteria. The results point out that the project is not feasible if benchmarked against purely financial criteria. Nevertheless, the introduction of the monetary values attained by the social and environmental benefits that the project brings, renders the whole development desirable and beneficial from a cost-benefit analysis standpoint.
Prediction of blast-induced ground vibrations with the use of artificial neural networks. A case study in Greece.
Authors: Xenios Z , Benardos A
Published: April 2021

Creating models, capable of making accurate predictions of the Peak Particle Velocity (PPV) after a blast, is always one of the researchers’ most important goals. The use of such prediction can assist in assessing the intensity of the blast vibrations and more importantly in designing the whole blasting phase so as to mitigate potential problems to nearby structures. Main aim of this paper is to demonstrate the capabilities of artificial intelligence applications in geotechnology and more specifically to assess PPV and the characteristics of the blast wave attenuation in an underground construction case study in Greece, using multilayer feed forward artificial neural networks (ANNs). The results showed that the forecasting ability of the developed ANNs was, in almost every case, more accurate than the ones given by the use of traditional empirical formulas, as benchmarked using Root Mean Squared Error (RMSE) and coefficient correlation (R). In this manner, the ANNs proved to be a reliable and accurate method to assess PPV from underground blasting and once trained they become an efficient off-the-shelf tool to assist engineers both in the blast design and in the mitigation of blast wave induced problems.
Underground heat mine – potential for large scale production and storage of thermal energy
Authors: Ahonen L , Hietava J , Korhonen K , Martinkauppi A , Piipponen K
Published: April 2021

We have studied possibilities to utilize the 1.4 km deep Pyhäsalmi mine as a source of geothermal energy. Measured thermal conductivities of the Precambrian (1.9 Ga) crystalline bedrock hosting the massive Cu-Zn sulphide deposit vary between 2.5 and 3.5 W/m·K, depending on the rock type, and the bedrock temperature increases with depth by 12–14 K/km. The design concept for heat utilization studied in this project is based on an underground borehole field exchanging heat between the bedrock and the water circulation loop, which then transfers thermal energy to the heat pumps. In the borehole heat exchanger (BHE) performance evaluations, we focused on a coaxial configuration, in which formation water circulates down in contact with borehole wall and returns inside a pipe. The borehole field modelled has a hemispherical geometry, so that all boreholes start from a central hall at the bottom of the mine (where the temperature is 21 °C) and would be directed radially outwards. Our reference case consists of 136 boreholes having length of 300 m, thus covering a rock volume of 57 million cubic meters. Simulations indicate that this BHE fields can sustain heating power of 1 MW for at least 44 years, but the average temperature of the borehole field would decrease by about 10 degrees. Thermal power can be increased substantially by increasing the borehole density, but the lifetime of the BHE field decreases.
Could ground heat and geothermal energy be the answer to climate change prevention and energy demand?
Authors: Vähäaho Ilkka
Published: April 2021

Global warming has caused and will continue to cause an increasing amount of extreme weather phenomena. Science has shown that the risks for irreversible and catastrophic changes will rise considerably if the climate warms up by more than 1.5 or even 2 degrees Celsius. The City of Helsinki bears its responsibility in mitigating climate change. The aim is to make Helsinki carbon neutral by 2035. The operating environment of energy produced by ground heat wells is changing in Finland – recently the interest in boring large energy well fields and deeper energy wells has increased considerably. There are two types of geothermal energy wells: wells based on a closed loop system and EGS wells, operating with the help of a network of clefts in the bedrock. EGS power stations are always associated with an earthquake risk, as they alter the stress state in the bedrock. The traditional ground heat wells are currently more cost-effective in Finland than the geothermal energy wells when their construction costs are compared with the value of the energy generated by them. The construction costs of geothermal energy solutions will most likely decrease along with future mass production. Geothermal energy wells will also bring many benefits compared with ground heat wells. In terms of underground construction, it is better to have fewer boreholes. Unlike traditional ground heat wells, geothermal energy will never run short over the years. The energy production of ground heat wells is typically calculated for a period of 20 to 50 years. Cooling also known as recharging will increase the lifespan of a ground heat system for some decades. The energy production of a two-kilometre deep geothermal energy well in the bedrock of Helsinki has been modelled for the next 1,000 years. The energy production of a two-kilometre deep geothermal energy well will initially reach 800 MWh annually and still be as high as 640 MWh annually after 1,000 years. Helsinki also aims to utilise renewable energy on a regional basis, and not only for individual building lots. Our intention is to integrate the utilisation of ground heat and geothermal energy as part of land-use planning. The pilot sites will include both new production and complementary development. This work is part of the background research for the Helsinki Underground Master Plan 2021.
Construction of Underground Service Tunnels as Part of Disaster Management
Authors: Suzuki Nanami , Shirane Tetsuya , Morimura Taira , Nitta Hiroyuki
Published: April 2021

Japan is one of the most earthquake-prone countries in the world. The Great East Japan Earthquake that struck on March 11, 2011 devastated a vast area centered on three prefectures in the Tohoku region (Fukushima, Miyagi, and Iwate), and there is said to be a more than 70% probability of a magnitude 7 earthquake striking Tokyo—the nation’s capital—within the next 30 years.

Under these circumstances, various measures are being considered for application to a range of facilities, transportation systems, and infrastructure in Japan in order to protect people’s lives and—at the very least—reduce damage in the event of an earthquake, but in reality no one can image the kind of situation that would unfold should an earthquake actually occur.

Sandwiched between Tokyo Station and the Imperial Palace in the center of Tokyo, the Otemachi, Marunouchi, and Yurakucho districts (known colloquially as the “Daimaruyu” area) comprise one huge business district where there is a concentration of representative Japanese companies—including major banks, trading companies, and newspapers—and Japan offices of foreign corporations. In addition to protecting human life, this area potentially faces another serious challenge in the event of a major earthquake—preventing disruption to the businesses operating within it.

In order to be able to do this, strengthening and redundancy of infrastructure such as energy, water, and heating and cooling systems are required. In order to achieve this strengthening and redundancy of energy, water, and heating/cooling infrastructure, utility and service tunnels for installing energy, water, and air-conditioning supply pipes are currently being constructed at a depth of 20–30 meters below ground in the Daimaruyu area. This paper provides an overview of the significance and purpose of this service tunnel construction as well as the project content.