Network Of Tunnels Research Articles

Structure-function relationship between soluble epoxide hydrolases structure and their tunnel network

Enzymes with buried active sites maintain their catalytic function via a single tunnel or tunnel network. In this study we analyzed the functionality of soluble epoxide hydrolases (sEHs) tunnel network, by comparing the overall enzyme structure with the tunnel’s shape and size. sEHs were divided into three groups based on their structure and the tunnel usage. The obtained results were compared with known substrate preferences of the studied enzymes, as well as reported in our other work evolutionary analyses data. The tunnel network architecture corresponded well with the evolutionary lineage of the source organism and large differences between enzymes were observed from long fragments insertions. This strategy can be used during protein re-engineering process for large changes introduction, whereas tunnel modification can be applied for fine-tuning of enzyme.

Studying the in vivo application of a liquid dermal scaffold in promoting wound healing in a mouse model.

Lack of matrix deposition is one of the main factors that complicates the healing process of wounds. The aim of this study was to test the efficacy and safety of a liquid dermal scaffold, referred to as MeshFill (MF) that can fill the complex network of tunnels and cavities which are usually found in chronic wounds and hence improve the healing process. We evaluated in vitro and in vivo properties of a novel liquid dermal scaffold in a delayed murine full-thickness wound model. We also compared this scaffold with two commercially available granular collagen-based products (GCBP). Liquid dermal scaffold accelerated wound closure significantly compared with no-treated control and collagen-based injectable composites in a delayed splinted wound model. When we compared cellular composition and count between MF, no treatment and GCBP at the histology level, it was found that MF was the most analogous and consistent with the normal anatomy of the skin. These findings were matched with the clinical outcome observation. The flowable in situ forming scaffold is liquid at cold temperature and gels after application to the wound site. Therefore, it would conform to the topography of the wound when liquid and provides adequate tensile strength when solidified. This patient-ready gelling dermal scaffold also contains the nutritional ingredients and therefore supports cell growth. Applying an injectable liquid scaffold that can fill wound gaps and generate a matrix to promote keratinocytes and fibroblasts migration, can result in improvement of the healing process of complex wounds.

Callio Lab – the deep underground research centre in Finland, Europe

Pyhäsalmi, in the Town of Pyhäjärvi, hosts one of the northernmost deep underground laboratories in Europe, the Callio Lab. Its origins are in underground physics (Centre for Underground Physics in Pyhäsalmi, CUPP), but gradually it has turned into a multi- and transdisciplinary research environment utilising both the surface and underground. Besides research, the infrastructure is open for business and innovation under the Callio – Mine for Business. The pre-investment for an underground pumped-hydro storage facility to be built at the area utilising the existing tunnel network for construction has been made. This investment ensures the existing and future utilisation of the underground and surface facilities.

A non-transmembrane channel formed by Ca2+-bound calsequestrin-2

Although it is well known that ion channels conduct ions across biomembranes, whether ions are conducted by some non-membrane proteins is not known because of the lack of a detection method. Calsequestrin-2 (CSQ2) is a sarcoplasmic reticulum (SR) Ca2+-binding protein suppling Ca2+ for the ryanodine receptor Ca2+ release during the excitation-contraction coupling in cardiomyocytes. CSQ2 mutations, even in some heterozygous occasions, causes catecholaminergic polymorphic ventricular tachycardia (CPVT2), suggesting that CSQ2 may function beyond a Ca2+ buffer. Here, we identify a non-transmembrane channel in Ca2+-enriched CSQ2 dimers, which facilitates fast Ca2+ mobilization. Using crystallography, we solved the high-resolution structure of Ca2+-bound CSQ2 and discovered that the negatively charged residues at the dimer interface encompassed a tubular channel-like structure, dubbed "tunnel," in which ∼15 Ca2+ ions aligned across the ∼5 nm tunnel path. To determine the potential tunnel conductance, we developed a graphene-based nanoelectronic technology to connect a CSQ2 dimer into a nanocircuit. In the Tyrode solution containing 1 mM Ca2+, a CSQ2 dimer exhibited a conductance one order of magnitude higher than the background level. This conductance was Ca2+ dependent, and was largely suppressed by the single-residue mutation D309N at the bottleneck region of the tunnel path, indicating that the tunnel conducted Ca2+ fluxes. When the D309N mutant CSQ2 was expressed in wild-type rat cardiomyocytes by adenoviral vectors, isoproterenol treatment induced chaotic Ca2+ waves, delayed after-depolarizations and trigged activities resembling those occurring in CPVT2 models. This dominant negative effect of CSQ2 mutation agreed well with our structural observation that CSQ2 tunnels were interconnected to form a tunnel network. Taken together, these results revealed that CSQ2 builds a nano-highway network for energy-efficient Ca2+ mobilization in the SR. Factors that block the Ca2+ highway may lead to arrhythmogenesis.

Predicting effective electrical resistivity and conductivity of carbon nanotube/carbon black-filled polymer matrix hybrid nanocomposites

A two-step analytical model based on a percolation network model and electron tunneling theory has been developed to predict the electrical resistivity and percolation threshold of a hybrid nanocomposite system comprising carbon black (CB) and carbon nanotube (CNT). The nanostructure of a tunneling network consisting of CNT and CB agglomerates has been generated to study the effects of various parameters on electrical conductivity. Electron tunneling is the primary mechanism for electrical percolation, which is incorporated into the model by considering the effective tunneling distance of CNTs. Later, a percolation network model is introduced to evaluate the electrical properties of the hybrid nanocomposite. Our results indicate that a high level of alignment leads to a significant decrease of the percolation threshold with an increase in conductivity, while a low CB volume fraction with low intrinsic electrical conductivity degrades the percolation and overall conductivity. Our results also reveal that the addition of CB as a second filler in a hybrid nanocomposite leads to improvements in conductance and percolation threshold. Analytical results show that the current model agrees well with existing experimental data, which reveals that tunneling and percolation are the dominant mechanisms for transition behavior in electrical conductivity.

Analysis of link failures and recoveries on 6to4 tunneling network with different routing protocol

Analysis of link failures and recoveries on 6to4 tunneling network with different routing protocol

Modeling of nonlinear water distribution networks by the finite element method

A discrete Finite Element model is developed to simulate the nonlinear pressure-discharge relationship in water networks. The model is applied to several cases of water distribution networks. Of particular interest is the success of the developed model in predicting accurately the heads and pipe flows at Hanoi water network and New York water tunnels network. An advantage of the proposed model is that the initial nodal pressure heads or pipe flows need not to be prescribed a priori. The finite element method has the advantages of handling very large network sizes, ease in adding various hydraulic elements to the network, and avoiding use of artificial loops. It is found that a combination of the Secant and Newton–Raphson methods reduces significantly the number of iterations. A new form of the head loss equation is suggested which allows for variation of the roughness, pipe diameter and discharge along each pipe.

Birds of a feather speak together: Understanding the different dialects of animals can help to decipher their communication.

As humans, many animal species that communicate via vocalization show a wide range of accents and dialects driven by environmental and social factors.

Edward de Bono: physician, psychologist, and inventor who coined the term “lateral thinking”

Credit: Roy Zhao One of five children, Edward Charles Francis Publius de Bono was born in Malta, to Joseph de Bono, a seventh generation Maltese physician, and Josephine (nee O’Byrne),...

Combined benefits of cooling with heat recovery for electrical cable tunnels in cities

Electrical power in cities is typically distributed by means of underground cable tunnels. The cables generate significant heat, and tunnel temperature is generally controlled via ventilation shafts with circulation to prevent overheating. If active cooling of the inlet air is provided, then temperatures can be lowered and electrical distribution losses reduced. This novel study, the first looking at cable tunnels with District Heating, investigates the effect and impact of heat recovery. The work combines technical and economic modelling together with measured data from a case study and shows significant benefits with wide-scale replication potential.A finite element (FE) model, for heat dissipation in a section of cable tunnel together with a spreadsheet model has shown that up to 460 kW of heat can be delivered to the local heating network for a single cooling point. The study indicates savings of 570 kg CO2e and 4000 kWh (of combined heat and electrical energy) per metre of tunnel per annum with reduced operating costs. Given the widespread network of cable and other tunnels in major cities, close to numerous heat users, the application of these techniques has major financial and low-carbon benefits for the UK and globally.

Assessment of Excavated Tunnels Stability in the Maya Archeological Area of Copán, Honduras

ABSTRACT Archaeological buried structures have received less attention than aboveground historical structures, which seems evident given the visual impact of the latter. Archaeological structures present specific issues related to stability during excavation and after being exposed. This paper addresses a UNESCO world heritage site in Honduras (Copan), which has about 4 km of tunnels in a complex organization that were dug, in the last 100 years, for the purpose of investigation of buried structures under a temple complex. The objective of this work is to assess the safety of the tunnels, helping on the decision of back-filling the tunnels, adding new masonry linings and allowing access in current conditions (possibly with measures to avoid water infiltration). First, the long network of tunnels was categorized into different sections either in an earthen fill only or in presence of a masonry lining. Then, the stability of these sections was discussed as a function of the increase of soil saturation. It was found that unlined tunnels safety is likely to be compromised for a saturation higher than 70%, whereas lined tunnels do not fail when the soil becomes fully saturated, as far as drainage is ensured. Finally, this work allowed to issue recommendations on actions related to the site.

Exploiting a Semi-Automatic Point Cloud Segmentation Method to Improve the Quality of Rock-Mass Characterization. The Cima Grappa Conservative Restoration Case Study

This paper presents results from applying semi-automatic point cloud segmentation methods in the underground tunnels within the Military Shrine’s conservative restoration project in Cima Grappa (Italy). The studied area, which has a predominant underground development distributed in a network of tunnels, is characterized by diffuse rock collapsing. In such a context, carrying out surveys and other technical operations are dangerous activities. Considering safety restrictions and unreachable impervious tunnels, having approached the study area with the scan-line survey technique resulted in only partial rock mass characterization. Hence, the geo-mechanical dataset was integrated, applying a semi-automatic segmentation method to the point clouds acquired through terrestrial laser scanning (TLS). The combined approach allowed for remote performance of detailed rock mass characterization, even remotely, in a short time and with a limited operators presence on site. Moreover, it permitted extending assessing tunnels’ stability and state of conservation to the inaccessible areas.

Water is Not Flowing Wireless, Even in Smart Tunnels: Addressing Critical Issues for the New Stormwater and Wastewater Network in L’Aquila (Italy)

As a consequence of the earthquake that struck L’Aquila (central Italy) on April 2009, the city is undergoing a complex process of reconstruction, not only aimed at the physical rehabilitation of the buildings, but also at the modernization and improvement of the utilities for an enhanced resilience and sustainability, towards the creation of a Smart City. The design of the Smart Tunnel, extending over the historical center of L’Aquila, has translated this new vision into reality. The basic idea behind the project is to collect and integrate the critical services in an underground concrete tunnel, in order to protect them from external threats and make them easily accessible and repairable, in case of disasters and/or for ordinary maintenance. This paper discusses critical hydraulic issues in the original project of the Smart Tunnel, highlighting that, for stormwater and wastewater networks, the adoption of a local design approach, without an appropriate consideration of external boundary conditions, could lead to ineffective solutions, because “water is not flowing wireless” even in Smart Tunnels.

Mineralogical and sample selection implications for geomechanical properties of intact heterogeneous and veined rocks from the Legacy skarn deposit

Abstract Predicting the geomechanical behaviour of rockmasses is key to the economic success and safety of rock engineering projects including surface and underground excavations. For these projects, unconfined compressive stress (UCS) laboratory testing provides fundamental geomechanical properties of intact rocks. It is currently standard practice for UCS testing to consider only homogeneous specimens that are free of defects and discard heterogeneous specimens such as those that contain intrablock structures (e.g. veins) or extra-granular defects (e.g. phenocrysts). Understanding the complexities of these heterogeneous rocks and rockmasses is critical for excavation projects such as deep cave mines where extensive tunnel networks, caves, and stopes are regularly excavated through heterogeneous rockmasses. This paper presents the test results and analyses of UCS tests conducted on 29 matrix-type and 21 veined drill core specimens from the Legacy Skarn deposit located in northern New Brunswick, Canada. These specimens are sorted into five lithological units: beige, red, and black varieties of quartz-plagioclase granodiorite, calcareous mudstone, and garnet-pyroxene skarn. Mineralogical compositions of these units are determined using field identification techniques and microscopic laboratory methods including petrographic thin section analysis, powdered X-Ray Diffraction, and micro-X-Ray Fluorescence. Significant effects of hydrothermal veining and phenocrysts on the UCS test results are discussed in this study to highlight the significant influence of mineralogy on the variability of geomechanical properties. For example, vein mineralogy dominated by calcite weakened the granodiorites but strengthened the calcareous mudstone. Vein mineralogy dominated by quartz in the skarn unit had a mixed influence on geomechanical properties. Vein thickness primarily influenced geomechanical properties of specimens with single veins, whereas vein density was more useful to characterize specimens that contained vein networks or stockwork. The effects of vein orientation only partially agree with the established Jaeger model for shear failure through critically oriented foliations. The disseminated alteration in the granodiorites (plagioclase phenocrysts) and skarn (garnet crystals) typically increased stiffness and strength as the large grains arrest crack propagation when under load. Lastly, the effects of sample selection on reported UCS test results using four sample selection methods are presented. The results demonstrate the importance of including heterogeneous veined specimens in UCS sample selection and testing programs to capture rock variability and improve the accuracy of numerical geomechanical design. Recommendations are made to improve geotechnical core logging and sample selection protocols when characterizing heterogeneous complex rockmasses.

Optimal Design of Pipe Networks Accounting for Future Demands and Phased Expansion using Integrated Dynamic Programming and Differential Evolution Approach

The water distribution network (WDN) design comprises determining optimal pipe sizes to achieve minimum cost pipe network to meet the required demands and performance levels. However, with time, the water demand for any region changes due to population, migration, and lifestyles, so interventions need to be made to the existing WDNs. Therefore, the capacity expansion problem consists of determining the suitable interventions at various stages such that the required demands are met at minimum cost. The present study proposed a novel methodology for planning such interventions based on Dynamic Programming (DP) formulation and presented a combined Self-Adaptive Differential Evolution and DP (SADE-DP) methodology for solving the WDN expansion problems considering life cycle costs. The methodology is applied and tested on three benchmark WDNs, namely New York Tunnel (NYT), Two loop (TL), and Blacksburg (BLA) networks, and also for a real case study of the Badlapur WDN in Maharashtra, India. The proposed model solutions are validated by comparing them with other WDN expansion methods taken from the literature. The results indicate that the proposed SADE-DP approach is computationally efficient and provides cost-effective solutions by meeting desired performance levels at various stages, and can serve as a potential alternative for solving real-world WDN expansion problems.

Nano-based Josephson Tunneling Networks and High Temperature Superconductivity

The search for superconductors with high values of the critical temperature has started shortly after the first observation of the phenomenon in 1911. At present, there are several paths towards reaching this goal. Here we focus on the direction based on observing high temperature superconducting state in some metallic nanoclusters. The macroscopic high Tc superconducting current can be provided by the Josephson tunneling between such clusters.

Guidance for Autonomous Underwater Vehicles in Confined Semistructured Environments.

In this work, we present the design, implementation, and testing of a guidance system for the UX-1 robot, a novel spherical underwater vehicle designed to explore and map flooded underground mines. For this purpose, it needs to navigate completely autonomously, as no communications are possible, in the 3D networks of tunnels of semistructured but unknown environments and gather various geoscientific data. First, the overall design concepts of the robot are presented. Then, the guidance system and its subsystems are explained. Finally, the system’s validation and integration with the rest of the UX-1 robot systems are presented. A series of experimental tests following the software-in-the-loop and the hardware-in-the-loop paradigms have been carried out, designed to simulate as closely as possible navigation in mine tunnel environments. The results obtained in these tests demonstrate the effectiveness of the guidance system and its proper integration with the rest of the systems of the robot, and validate the abilities of the UX-1 platform to perform complex missions in flooded mine environments.

Application of the Virtual Reality Technology in Structural Safety Monitoring of Shield Tunnels

Many structural health monitoring (SHM) systems of actual tunnels are underused, with abstract data, chaotic information and the diagnostic results beyond comprehension. It is necessary to establish the visual connection between the visualization of monitoring network and massive structural information of tunnels. To address this issue, this study proposed a structural visualization method based on the panoramic virtual reality technology, combining the panoramic spherical image and the real-time monitoring data of tunnel obtained from SHM system. First, a software system for structural safety monitoring of an actual shield tunnel was developed on the basis of the combination of the panoramic visual technology and B/S (Browser/Server) architecture system. Second, the panoramic modelling method for specific tunnel structure environment was discussed in detail, and then the mechanism of data transmission and information access in panoramic virtual reality environment was investigated deeply. Finally, in view of the demands of practical application, the function modules of the abovementioned software system were described. Some key issues of how to develop each software module using the panoramic virtual reality technique were analysed e.g., online geographic information and cloud platform management. The results show that the panoramic virtual reality technology completely meets the needs of real-time processing, information management, virtual roaming and maintenance management in tunnel structural safety monitoring.

Assessment of optimal water distribution systems design under steady-state and transient conditions due to pipe roughness uncertainty

This paper presents a methodology to find the optimal design or rehabilitation of water distribution system (WDS) under both steady-state and transient conditions. Then, assessing the obtained optimal solution and studying its stability, reliability, due to uncertainty in pipe roughness coefficients (CHW). The WDS optimization objective is to minimize the rehabilitation cost by installing new pipes parallel to the existing ones achieving all hydraulic constraints. For this purpose, particle swarm optimization (PSO) is used as an optimization tool and Monte Carlo simulation (MCS) is applied to generate multiple realizations of CHW for different coefficient of variation (COVCHW). A comparison between crisp shape and continuous shape (S-shape) fuzzy membership functions is carried out to study the hydraulic availability indices to nodal pressure head values resulted from pipe roughness uncertainty. Both steady-state nodal and system reliabilities are estimated while, only the transient system reliability is calculated for the obtained optimal solution. The proposed methodology is applied on the New York City tunnel network (NYCTN) and the corresponding reliability is analyzed. Results show that as pipe roughness uncertainty increases, WDS reliability decreases.

A “Drug Sweeping” State of the TriABC Triclosan Efflux Pump from Pseudomonas aeruginosa

The structure of the TriABC inner membrane component of the triclosan/SDS-specific efflux pump from Pseudomonas aeruginosa was determined by cryoelectron microscopy to 4.5Å resolution. The complete structure of the inner membrane transporter TriC of the resistance-nodulation-division (RND) superfamily was solved, including a partial structure of the fused periplasmic membrane fusion subunits, TriA and TriB. The substrate-free conformation of TriABC represents an intermediate step in efflux complex assembly before the engagement of the outer membrane channel. Structural analysis identified a tunnel network whose constriction impedes substrate efflux, indicating inhibition of TriABC in the unengaged state. Blind docking studies revealed binding to TriC at the same loci by substrates and bulkier non-substrates. Together with functional analyses, we propose that selective substrate translocation involves conformational gating at the tunnel narrowing that, together with conformational ordering of TriA and TriB, creates an engaged state capable of mediating substrate efflux.