Measuring evaporation distribution of mud brick and rammed earth

2014 ◽  
Vol 32 (1) ◽  
pp. 32-48 ◽  
Author(s):  
Enrico Fodde ◽  
Kunio Watanabe ◽  
Yukiyasu Fujii
Keyword(s):  
Structural Damage ◽  
Three Dimensional ◽  
Eighth Century ◽  
Protective Measure ◽  
Water Evaporation ◽  
Surface Erosion ◽  
Salt Weathering ◽  
Content Type ◽  
Central Asian ◽  
Repair Materials

Purpose – Salt weathering is one of the most common agents of decay of Central Asian earthen sites and is in function of water evaporation from the wall surface. Soon after excavation the earthen walls and the stupa of the Buddhist temple of Ajina Tepa (seventh-eighth century AD) started to deteriorate due lack of protection and surface erosion. The most important issue in the planning of conservation work was to understand such mechanisms and to decrease the effect of salt weathering on structural damage. The purpose of this paper is to discuss these issues. Design/methodology/approach – Evaporation distribution and salts types were studied on selected walls. In addition, three-dimensional recording of the walls and the stupa was undertaken with digital photogrammetric methods. Findings – It was clearly found that the intensity of salt weathering in the site is high and some salts such as halite (sodium chloride) are thought to originate from groundwater. On the basis of the results obtained, thick shelter coating with mud brick and mud render was designed and constructed as protective measure for the earthen walls. Practical implications – Those walls that were most affected by salts weathering and erosion at the base (coving) became structurally less sound and eventually collapsed if not conserved. Originality/value – The work is the first attempt in the design of a methodology for the selection of earthen repair materials and methods.

Numerical simulation of methane spreading in porous media after leaking from an underground pipe

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ji Wang ◽  
Yuting Yan ◽  
Junming Li
Keyword(s):  
Heat Transfer ◽  
Porous Media ◽  
Numerical Model ◽  
Natural Gas ◽  
Three Dimensional ◽  
Ground Surface ◽  
Air Transportation ◽  
Water Evaporation ◽  
Content Type ◽  
Gas Leak

Purpose Natural gas leak from underground pipelines could lead to serious damage and global warming, whose spreading in soil should be systematically investigated. This paper aims to propose a three-dimensional numerical model to analyze the methane–air transportation in soil. The results could help understand the diffusion process of natural gas in soil, which is essential for locating leak source and reducing damage after leak accident. Design/methodology/approach A numerical model using finite element method is proposed to simulate the methane spreading process in porous media after leaking from an underground pipe. Physical models, including fluids transportation in porous media, water evaporation and heat transfer, are taken into account. The numerical results are compared with experimental data to validate the reliability of the simulation model. The effects of methane leaking direction, non-uniform soil porosity, leaking pressure and convective mass transfer coefficient on ground surface are analyzed. Findings The methane mole fraction distribution in soil is significantly affected by the leaking direction. Horizontally and vertically non-uniform soil porosity has a stronger effect. Increasing leaking pressure causes increasing methane mole flux and flow rate on the ground surface. Originality/value Most existing gas diffusion models in porous media are for one- or two-dimensional simulation, which is not enough for predicting three-dimensional diffusion process after natural gas leak in soil. The heat transfer between gas and soil was also neglected by most researchers, which is very important for predicting the gas-spreading process affected by the soil moisture variation because of water evaporation. In this paper, a three-dimensional numerical model is proposed to further analyze the methane–air transportation in soil using finite element method, with the presence of water evaporation and heat transfer in soil.

Stereotactic radiosurgery versus stereotactic radiotherapy for patients with vestibular schwannoma: a Leksell Gamma Knife Society 2000 debate

2000 ◽  
Vol 93 (supplement_3) ◽  
pp. 90-92 ◽  
Author(s):  
Mark E. Linskey
Keyword(s):  
Gamma Knife ◽  
Stereotactic Radiotherapy ◽  
Three Dimensional ◽  
Late Recurrence ◽  
Vestibular Schwannomas ◽  
Tumor Control ◽  
Complication Rates ◽  
Content Type ◽  
Single Fraction ◽  
Fine Print

✓ By definition, the term “radiosurgery” refers to the delivery of a therapeutic radiation dose in a single fraction, not simply the use of stereotaxy. Multiple-fraction delivery is better termed “stereotactic radiotherapy.” There are compelling radiobiological principles supporting the biological superiority of single-fraction radiation for achieving an optimal therapeutic response for the slowly proliferating, late-responding, tissue of a schwannoma. It is axiomatic that complication avoidance requires precise three-dimensional conformality between treatment and tumor volumes. This degree of conformality can only be achieved through complex multiisocenter planning. Alternative radiosurgery devices are generally limited to delivering one to four isocenters in a single treatment session. Although they can reproduce dose plans similar in conformality to early gamma knife dose plans by using a similar number of isocenters, they cannot reproduce the conformality of modern gamma knife plans based on magnetic resonance image—targeted localization and five to 30 isocenters. A disturbing trend is developing in which institutions without nongamma knife radiosurgery (GKS) centers are championing and/or shifting to hypofractionated stereotactic radiotherapy for vestibular schwannomas. This trend appears to be driven by a desire to reduce complication rates to compete with modern GKS results by using complex multiisocenter planning. Aggressive advertising and marketing from some of these centers even paradoxically suggests biological superiority of hypofractionation approaches over single-dose radiosurgery for vestibular schwannomas. At the same time these centers continue to use the term radiosurgery to describe their hypofractionated radiotherapy approach in an apparent effort to benefit from a GKS “halo effect.” It must be reemphasized that as neurosurgeons our primary duty is to achieve permanent tumor control for our patients and not to eliminate complications at the expense of potential late recurrence. The answer to minimizing complications while maintaining maximum tumor control is improved conformality of radiosurgery dose planning and not resorting to homeopathic radiosurgery doses or hypofractionation radiotherapy schemes.

scholarly journals Agent-Based Modeling Demonstrates How Local Chemotactic Behavior Can Shape Biofilm Architecture

mSphere ◽  
2019 ◽  
Vol 4 (3) ◽  
Author(s):  
Emily G. Sweeney ◽  
Andrew Nishida ◽  
Alexandra Weston ◽  
Maria S. Bañuelos ◽  
Kristin Potter ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Three Dimensional ◽  
Structural Features ◽  
Agent Based Modeling ◽  
Emergent Properties ◽  
Cellular Interactions ◽  
Biofilm Growth ◽  
Content Type ◽  
Agent Based ◽  
H Pylori

ABSTRACTBacteria are often found living in aggregated multicellular communities known as biofilms. Biofilms are three-dimensional structures that confer distinct physical and biological properties to the collective of cells living within them. We used agent-based modeling to explore whether local cellular interactions were sufficient to give rise to global structural features of biofilms. Specifically, we asked whether chemorepulsion from a self-produced quorum-sensing molecule, autoinducer-2 (AI-2), was sufficient to recapitulate biofilm growth and cellular organization observed for biofilms ofHelicobacter pylori, a common bacterial resident of human stomachs. To carry out this modeling, we modified an existing platform, Individual-based Dynamics of Microbial Communities Simulator (iDynoMiCS), to incorporate three-dimensional chemotaxis, planktonic cells that could join or leave the biofilm structure, and cellular production of AI-2. We simulated biofilm growth of previously characterizedH. pyloristrains with various AI-2 production and sensing capacities. Using biologically plausible parameters, we were able to recapitulate both the variation in biofilm mass and cellular distributions observed with these strains. Specifically, the strains that were competent to chemotax away from AI-2 produced smaller and more heterogeneously spaced biofilms, whereas the AI-2 chemotaxis-defective strains produced larger and more homogeneously spaced biofilms. The model also provided new insights into the cellular demographics contributing to the biofilm patterning of each strain. Our analysis supports the idea that cellular interactions at small spatial and temporal scales are sufficient to give rise to larger-scale emergent properties of biofilms.IMPORTANCEMost bacteria exist in aggregated, three-dimensional structures called biofilms. Although biofilms play important ecological roles in natural and engineered settings, they can also pose societal problems, for example, when they grow in plumbing systems or on medical implants. Understanding the processes that promote the growth and disassembly of biofilms could lead to better strategies to manage these structures. We had previously shown thatHelicobacter pyloribacteria are repulsed by high concentrations of a self-produced molecule, AI-2, and thatH. pylorimutants deficient in AI-2 sensing form larger and more homogeneously spaced biofilms. Here, we used computer simulations of biofilm formation to show that localH. pyloribehavior of repulsion from high AI-2 could explain the overall architecture ofH. pyloribiofilms. Our findings demonstrate that it is possible to change global biofilm organization by manipulating local cell behaviors, which suggests that simple strategies targeting cells at local scales could be useful for controlling biofilms in industrial and medical settings.

Plasmonic silver nanoparticles embedded in flexible three-dimensional carbonized melamine foam with enhanced solar-driven water evaporation

Desalination ◽  
2021 ◽  
Vol 507 ◽  
pp. 115038
Author(s):  
Yanying Shi ◽  
Chaofan Zhang ◽  
Yuhui Wang ◽  
Yuming Cui ◽  
Qingyao Wang ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Three Dimensional ◽  
Water Evaporation ◽  
Melamine Foam

A biomimetic 3D airflow sensor made of an array of two piezoelectric metal-core fibers

Sensor Review ◽  
2017 ◽  
Vol 37 (3) ◽  
pp. 312-321 ◽  
Author(s):  
Yixiang Bian ◽  
Can He ◽  
Kaixuan Sun ◽  
Longchao Dai ◽  
Hui Shen ◽  
...  
Keyword(s):  
Design Methodology ◽  
Spherical Surface ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Piezoceramic Cylinder ◽  
Metal Core ◽  
Content Type ◽  
3D Space ◽  
Highly Sensitive ◽  
Airflow Sensor

Purpose The purpose of this paper is to design and fabricate a three-dimensional (3D) bionic airflow sensing array made of two multi-electrode piezoelectric metal-core fibers (MPMFs), inspired by the structure of a cricket’s highly sensitive airflow receptor (consisting of two cerci). Design/methodology/approach A metal core was positioned at the center of an MPMF and surrounded by a hollow piezoceramic cylinder. Four thin metal films were spray-coated symmetrically on the surface of the fiber that could be used as two pairs of sensor electrodes. Findings In 3D space, four output signals of the two MPMFs arrays can form three “8”-shaped spheres. Similarly, the sensing signals for the same airflow are located on a spherical surface. Originality/value Two MPMF arrays are sufficient to detect the speed and direction of airflow in all three dimensions.

Comparison of the reluctance laminated and solid rotor synchronous machine operating at high temperatures

2019 ◽  
Vol 38 (4) ◽  
pp. 1111-1119 ◽  
Author(s):  
Marcin Lefik ◽  
Krzysztof Komeza ◽  
Ewa Napieralska-Juszczak ◽  
Daniel Roger ◽  
Piotr Andrzej Napieralski
Keyword(s):  
High Speed ◽  
Design Methodology ◽  
Three Dimensional ◽  
Synchronous Machine ◽  
Point Of View ◽  
Heat Sources ◽  
Model Calculations ◽  
Content Type ◽  
Thermal Phenomenon ◽  
Practical Implications

Purpose The purpose of this paper is to present a comparison between reluctance synchronous machine-enabling work at high internal temperature (HT° machine) with laminated and solid rotor. Design/methodology/approach To obtain heat sources for the thermal model, calculations of the electromagnetic field were made using the Opera 3D program including effect of rotation and the resulting eddy current losses. To analyse the thermal phenomenon, the 3D coupled thermal-fluid (CFD) model is used. Findings The presented results show clearly that laminated construction is much better from a point of view of efficiency and temperature. However, solid construction can be interesting for high speed machines due to their mechanical robustness. Research limitations/implications The main problem, despite the use of parallel calculations, is the long calculation time. Practical implications The obtained simulation and experimental results show the possibility of building a machine operating at a much higher ambient temperature than it was previously produced for example in the vicinity of the aircraft turbines. Originality/value The paper presents the application of fully three-dimensional coupled electromagnetic and thermal analysis of new machine constructions designed for elevated temperature.

The generation of adaptive assembly from predicting change propagation

2015 ◽  
Vol 35 (3) ◽  
pp. 269-280 ◽  
Author(s):  
Hu Qiao ◽  
Rong Mo ◽  
Ying Xiang
Keyword(s):  
Computer Aided Design ◽  
Three Dimensional ◽  
Original Method ◽  
Change Propagation ◽  
Assembly Model ◽  
Practical Application ◽  
Content Type ◽  
Design Structure ◽  
Aided Design ◽  
Practical Implications

Purpose – The purpose of this paper is to establish an adaptive assembly, to realize the adaptive changing of the models and to improve the flexibility and reliability of assembly change. For a three-dimensional (3D) computer-aided design (CAD) assembly in a changing process, there are two practical problems. One is delivering parameters’ information not smoothly. The other one is to easily destroy an assembly structure. Design/methodology/approach – The paper establishes associated parameters design structure matrix of related parts, and predicts possible propagation paths of the parameters. Based on the predicted path, structured storage is made for the affected parameters, tolerance range and the calculation relations. The study combines structured path information and all constrained assemblies to build the adaptive assembly, proposes an adaptive change algorithm for assembly changing and discusses the extendibility of the adaptive assembly. Findings – The approach would improve the flexibility and reliability of assembly change and be applied to different CAD platform. Practical implications – The examples illustrate the construction and adaptive behavior of the assembly and verify the feasibility and reasonability of the adaptive assembly in practical application. Originality/value – The adaptive assembly model proposed in the paper is an original method to assembly change. And compared with other methods, good results have been obtained.

Robotic motion compensation for bone movement, using ultrasound images

2015 ◽  
Vol 42 (5) ◽  
pp. 466-474 ◽  
Author(s):  
P.M.B. Torres ◽  
P. J. S. Gonçalves ◽  
J.M.M. Martins
Keyword(s):  
Motion Compensation ◽  
Optical Measurement ◽  
Three Dimensional ◽  
Point Clouds ◽  
Robotic System ◽  
Ultrasound Images ◽  
Bone Drilling ◽  
Content Type ◽  
3D Point Clouds ◽  
Robotic Motion

Purpose – The purpose of this paper is to present a robotic motion compensation system, using ultrasound images, to assist orthopedic surgery. The robotic system can compensate for femur movements during bone drilling procedures. Although it may have other applications, the system was thought to be used in hip resurfacing (HR) prosthesis surgery to implant the initial guide tool. The system requires no fiducial markers implanted in the patient, by using only non-invasive ultrasound images. Design/methodology/approach – The femur location in the operating room is obtained by processing ultrasound (USA) and computer tomography (CT) images, obtained, respectively, in the intra-operative and pre-operative scenarios. During surgery, the bone position and orientation is obtained by registration of USA and CT three-dimensional (3D) point clouds, using an optical measurement system and also passive markers attached to the USA probe and to the drill. The system description, image processing, calibration procedures and results with simulated and real experiments are presented and described to illustrate the system in operation. Findings – The robotic system can compensate for femur movements, during bone drilling procedures. In most experiments, the update was always validated, with errors of 2 mm/4°. Originality/value – The navigation system is based entirely on the information extracted from images obtained from CT pre-operatively and USA intra-operatively. Contrary to current surgical systems, it does not use any type of implant in the bone to track the femur movements.

Combatting organised crime and terrorism in Central Asia

2018 ◽  
Vol 25 (2) ◽  
pp. 309-319 ◽  
Author(s):  
Emma van Santen
Keyword(s):  
Central Asia ◽  
Explanatory Power ◽  
Academic Research ◽  
Organised Crime ◽  
The State ◽  
State Crime ◽  
International Policy ◽  
Content Type ◽  
Central Asian ◽  
Terrorist Groups

Purpose This paper aims to examine the shift away from the traditional distinction between organised crime and terrorist groups towards their conceptual convergence under the crime-terror nexus narrative in the context of international security and development policy in post-Soviet Central Asia. It assesses the empirical basis for the crime-terror and state-crime nexus in three Central Asian countries – Kyrgyzstan, Tajikistan and Uzbekistan – and argues that the exclusion of the state from the analytical framework undermines the relevance of the crime-terror paradigm for policy-making. Design/methodology/approach This paper draws on a literature review of academic research, recent case studies highlighting new empirical evidence in Central Asia and international policy publications. Findings There is a weak empirical connection between organised crime and Islamic extremists, such as the Islamic Movement of Uzbekistan and Hizbut Tahrir, in Central Asia. The state-crime paradigm, including concepts of criminal capture, criminal sovereignty and criminal penetration, hold more explanatory power for international policy in Central Asia. The crime-terror paradigm has resulted in a narrow and ineffective security-oriented law enforcement approach to counter-narcotics and counter-terrorism but does not address the underlying weak state governance structures and political grievances that motivate organised crime and terrorist groups respectively. Originality/value International policy and scholarship is currently focussed on the areas of convergence between organised crime and terrorist groups. This paper highlights the continued relevance of the traditional conceptual separation of terrorist and organised crime groups based on their different motives, methods and relationship with the state, for security and democratic governance initiatives in the under-researched Central Asian region.

Thermo-mechanical coupling particle simulation of three-dimensional large-scale non-isothermal problems

2017 ◽  
Vol 34 (5) ◽  
pp. 1551-1571 ◽  
Author(s):  
Ming Xia
Keyword(s):  
Large Scale ◽  
Three Dimensional ◽  
Simulation Method ◽  
Particle Simulation ◽  
Similarity Criteria ◽  
Particle Model ◽  
Length Scale ◽  
Content Type ◽  
Mechanical Coupling ◽  
Particle Simulation Method

Purpose The main purpose of this paper is to present a comprehensive upscale theory of the thermo-mechanical coupling particle simulation for three-dimensional (3D) large-scale non-isothermal problems, so that a small 3D length-scale particle model can exactly reproduce the same mechanical and thermal results with that of a large 3D length-scale one. Design/methodology/approach The objective is achieved by following the scaling methodology proposed by Feng and Owen (2014). Findings After four basic physical quantities and their similarity-ratios are chosen, the derived quantities and its similarity-ratios can be derived from its dimensions. As the proposed comprehensive 3D upscale theory contains five similarity criteria, it reveals the intrinsic relationship between the particle-simulation solution obtained from a small 3D length-scale (e.g. a laboratory length-scale) model and that obtained from a large 3D length-scale (e.g. a geological length-scale) one. The scale invariance of the 3D interaction law in the thermo-mechanical coupled particle model is examined. The proposed 3D upscale theory is tested through two typical examples. Finally, a practical application example of 3D transient heat flow in a solid with constant heat flux is given to illustrate the performance of the proposed 3D upscale theory in the thermo-mechanical coupling particle simulation of 3D large-scale non-isothermal problems. Both the benchmark tests and application example are provided to demonstrate the correctness and usefulness of the proposed 3D upscale theory for simulating 3D non-isothermal problems using the particle simulation method. Originality/value The paper provides some important theoretical guidance to modeling 3D large-scale non-isothermal problems at both the engineering length-scale (i.e. the meter-scale) and the geological length-scale (i.e. the kilometer-scale) using the particle simulation method directly.

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