Simplified model for the non-linear behaviour representation of reinforced concrete columns under biaxial bending

In the present paper a simplified model is proposed for the force-deformation behaviour of reinforced concrete members under biaxial loading combined with axial force. The starting point for the model development was an existing fixed-length plastic hinge element model that accounts for the non-linear hysteretic behaviour at the element end-sections, characterized by trilinear moment-curvature laws. To take into account the section biaxial behaviour, the existing model was adopted for both orthogonal lateral directions and an interaction function was introduced to couple the hysteretic response of both directions. To calibrate the interaction function it were used numerical results, obtained from fibre models, and experimental results. For the parameters identification, non-linear optimization approaches were adopted, namely: the gradient based methods followed by the genetic, evolutionary and nature-inspired algorithms. Finally, the simplified non-linear model proposed is validated through the analytical simulation of biaxial test results carried out in full-scale reinforced concrete columns

Design of a Solar Panel Deployment and Tracking System for Pocketqube Pico-Satellite

Modularized small satellites will have even greater potential with better energy supply. In this paper, a PocketQube solar panel deployment and tracking system will be presented. The system is designed for a 3P PocketQubes. During the designing phase, trade-off analysis is done to meet the balance of weight, dimension and efficiency. Reliability, manufacturability, and cost are also considered from the beginning, as commercial production and launch are expected. The CAD design, dynamics analysis, motion simulation, and rendering for the project are undertaken by Solidworks, whereas Abaqus CAE is utilized for the finite element analysis of the vibration test of the panels. In the gimbal subsystem, we use two micro stepper motor to drive the panels via a two-axis gearbox, enabling the panels to track the sun omnidirectionally. In the panel subsystem, two types of customized spring hinges are designed. Robust and verified parts, such as burner resistors, are chose for the control and deployment system. After the continuous optimization process throughout the design phase, by comparing different manufacturing processes technologies, materials, and design details, the full scale prototypes of the gimbal subsystem were built and tested. In the end, the most feasible solution, as well as the suggestions for the development, were put forward

Never-Land | A Parasitic and Accumulative Approach to Urbanization in China

Ever since 1960s, European situationist and Japanese metabolist architects constantly reject the uniformity and totalitarian of modern architecture/urban design, seeking parasitic and dynamic approaches to post-war urbanization. Projects such as the Plug-In City and the Tokyo Bay dream of alternative urban scenarios by reversing traditional perceptions of infrastructure’s role in the city, combining architecture, technology and society together. However, these megastructure projects not only neglect the existing urban context but also lack political and economic driving force. As a result, they are considered utopian by many contemporary critics. Fifty years later in China, fast urbanization process creates problems for both cities and people live in them. On one hand, massive construction sites create urban voids, disrupting the city’s identity. On the other hand, migrant workers get excluded from city’s social life, living a dystopian lifestyle. However, China’s centralized government and booming construction market provide strong political and economic support for a revolutionary urban experimentation, while the omnipresent construction sites and migrant workers offer appropriate location, labor and social requirement for an alternative architectural implementation. It is time to have a retrospective view at the idea of parasitic urbanism back in the 60s, readjusting it and applying it to current situation in China. The thesis re-imagines the operation and impact of construction sites under fast urbanization in China, by studying the live + work practices of migrant construction workers. The thesis criticizes the existing introverted “W all + Hut” construction paradigm, proposing an adaptable architectural structure around construction sites, which provides spatially an alternativ e urban nomad lifestyle for Chinese construction workers, and in return reconstruct the urban experience in China based on the increasing demand for migrant-dwellings and omnipresent construction sites

Translating bus information into sign language for deaf people

This paper describes the application of language translation technologies for generating bus information in Spanish Sign Language (LSE: Lengua de Signos Española). In this work, two main systems have been developed: the first for translating text messages from information panels and the second for translating spoken Spanish into natural conversations at the information point of the bus company. Both systems are made up of a natural language translator (for converting a word sentence into a sequence of LSE signs), and a 3D avatar animation module (for playing back the signs). For the natural language translator, two technological approaches have been analyzed and integrated: an example-based strategy and a statistical translator. When translating spoken utterances, it is also necessary to incorporate a speech recognizer for decoding the spoken utterance into a word sequence, prior to the language translation module. This paper includes a detailed description of the field evaluation carried out in this domain. This evaluation has been carried out at the customer information office in Madrid involving both real bus company employees and deaf people. The evaluation includes objective measurements from the system and information from questionnaires. In the field evaluation, the whole translation presents an SER (Sign Error Rate) of less than 10% and a BLEU greater than 90%

Vitamin D. a dynamic molecule. how relevant might the dynamism for a vitamin be

Cholecalciferol, the precursor of Vitamin D3, is a very old, highly conserved, molecule. Its presence is evident in non-mineralized 750 million-year-old living species, such as plankton. The more active metabolites, a receptor and a D binding protein, appear later, along with the increasing complexity of animal species living in the sea. In the sea, however, the biological function of vitamin D is unlikely to be linked with mineral metabolism, and we can hypothesize a relationship with an immune response. It is in terrestrial animals exhibiting cellular bone that the complexity of vitamin D increases. At this stage of evolution, we see the appearance of bone cells that are capable of producing hormones that regulate and are regulated by vitamin D. This interaction starts a sophisticated metabolic system that modulates both mineral and energy metabolism for the requirements of the musculoskeletal system. Among the so-called pleiotropic effects of vitamin D, those resulting from the inhibitory effect on the renin-angiotensin system are of particular interest for nephrologists. Intriguingly, however, more than for anti-hypertensive effects, this interaction could be relevant for anti-inflammatory actions, possibly representative of a residual ancestral role of vitamin D. In addition, this evolutionary dynamism of the vitamin D system should not be separated from the chemical dynamism that characterizes the ligand molecule and its specific receptor. Both are capable of significant tridimensional modifications that contribute to an increase in the variability and the partial predictability of their final biological effect. A dynamic overview of this system that takes into account its evolutionary and adaptive aspects may be helpful to understand its biological complexity and to envisage why using vitamin D metabolites for therapeutic purposes is still a matter of debate

3D Reconstruction & Assessment Framework based on affordable 2D Lidar

Lidar is extensively used in the industry and mass-market. Due to its measurement accuracy and insensitivity to illumination compared to cameras, It is applied onto a broad range of applications, like geodetic engineering, self driving cars or virtual reality. But the 3D Lidar with multi-beam is very expensive, and the massive measurements data can not be fully leveraged on some constrained platforms. The purpose of this paper is to explore the possibility of using cheap 2D Lidar off-the-shelf, to preform complex 3D Reconstruction, moreover, the generated 3D map quality is evaluated by our proposed metrics at the end. The 3D map is constructed in two ways, one way in which the scan is performed at known positions with an external rotary axis at another plane. The other way, in which the 2D Lidar for mapping and another 2D Lidar for localization are placed on a trolley, the trolley is pushed on the ground arbitrarily. The generated maps by different approaches are converted to octomaps uniformly before the evaluation. The similarity and difference between two maps will be evaluated by the proposed metrics thoroughly. The whole mapping system is composed of several modular components. A 3D bracket was made for assembling of the Lidar with a long range, the driver and the motor together. A cover platform made for the IMU and 2D Lidar with a shorter range but high accuracy. The software is stacked up in different ROS packages.Comment: 7 pages, 9 Postscript figures. Accepted by 2018 IEEE International Conference on Advanced Intelligent Mechatronic

Polycrystal model of the mechanical behavior of a Mo-TiC30vol.% metal-ceramic composite using a 3D microstructure map obtained by a dual beam FIB-SEM

The mechanical behavior of a Mo-TiC30 vol.% ceramic-metal composite was investigated over a large temperature range (25^{\circ}C to 700^{\circ}C). High-energy X-ray tomography was used to reveal the percolation of the hard titanium carbide phase through the composite. Using a polycrystal approach for a two-phase material, finite element simulations were performed on a real 3D aggregate of the material. The 3D microstructure, used as starting configuration for the predictions, was obtained by serial-sectioning in a dual beam Focused Ion Beam (FIB)-Scanning Electron Microscope (SEM) coupled to an Electron Back Scattering Diffraction system (3D EBSD, EBSD tomography). The 3D aggregate consists of a molybdenum matrix and a percolating TiC skeleton. As most BCC metals, the molybdenum matrix phase is characterized by a change in the plasticity mechanisms with temperature. We used a polycrystal model for the BCC material, which was extended to two phases (TiC and Mo). The model parameters of the matrix were determined from experiments on pure molydenum. For all temperatures investigated, the TiC particles were considered as brittle. Gradual damage of the TiC particles was treated, based on an accumulative failure law that is approximated by an evolution of the apparent particle elastic stiffness. The model enabled us to determine the evolution of the local mechanical fields with deformation and temperature. We showed that a 3D aggregate representing the actual microstructure of the composite is required to understand the local and global mechanical properties of the studied composite

Microbially induced carbonate precipitation for seepage-induced internal erosion control in sand-clay mixtures

Earth embankment dams are one of the most commonly constructed hydraulic infrastructures worldwide. One mode of dam failure is piping through the embankment, which is initiated by internal erosion of soil particles inside dams. In this study, the applicability of microbially induced carbonate precipitation (MICP) for internal erosion control is examined in the laboratory using sand-kaolin mixtures of different particle sizes. A series of internal erosion tests are conducted using a newly designed rigid-wall column erosion test apparatus, which allows independent control of MICP treatment. Erosion rate/coefficient, volumetric change and permeability are characterized during the internal erosion process. It is found that MICP treatment facilitates the reduction of erosion and volumetric contraction of sand-clay mixtures investigated in the current study. Carbonate precipitation increases the erosion resistance of sand-clay mixtures by absorbing/coating fine particles directly and bridging the contacts of coarse particles. An improved effectiveness of internal erosion control is observed in the sand- clay mixture having a higher gap ratio. This observation is due to the inherently large porosity, which hosts more carbonate precipitation. The difficulty of bacteria and chemical injection in sand-clay mixtures triggers the flushing of produced calcium carbonate, which reduces the overall carbonate content and MICP treatment efficiency. The spatial distribution of precipitation within the soil is also altered.China Scholarship Council (CSC)This is the author accepted manuscript. It is currently under an indefinite embargo pending publication by the American Society of Civil Engineers

Peculiarities of geological and thermobaric conditions for the gas hydrate deposits occurence in the Black Sea and the prospects for their development

The actuality has been revealed of the necessity to attract the gas hydrate deposits of the Black Sea into industrial development as an alternative to traditional gas fields. This should be preceded by the identification and synthesis of geological and thermobaric peculiarities of their existence. It was noted that the gas hydrates formation occurs under certain thermobaric conditions, with the availability of a gas hydrate-forming agent, which is capable of hydrate formation, as well as a sufficient amount of water necessary to start the crystallization process. The gas hydrate accumulation typically does not occur in free space – in sea water, but in the massif of the sea bed rocks. The important role in the process of natural gas hydrates formation is assigned to thermobaric parameters, as well as to the properties and features of the geological environment, in which, actually, the process of hydrate formation and further hydrate accumulation occurs. It was noted that the source of formation and accumulation of the Black Sea gas hydrates is mainly catagenetic (deep) gas, but diagenetic gas also takes part in the process of gas hydrate deposits formation. The main component of natural gas hydrate deposits is methane and its homologs – ethane, propane, isobutane. The analysis has been made of geological and geophysical data and literature materials devoted to the study of the offshore area and the bottom of the Black Sea, as well as to the identification of gas hydrate deposits. It was established that in the offshore area the gas hydrate deposits with a heterogeneous structure dominate, that is, which comprises a certain proportion of aluminosilicate inclusions. It was noted that the Black Sea bottom sediments, beginning with the depths of 500 – 600 m, are gassy with methane, and a large sea part is favourable for hydrate formation at temperatures of +8...+9ºC and pressures from 7 to 20 MPa at different depths. The characteristics of gas hydrate deposits are provided, as well as requirements and aspects with regard to their industrialization and development. It is recommended to use the method of thermal influence on gas hydrate deposits, since, from an ecological point of view, it is the safest method which does not require additional water resources for its implementation, because water intake is carried out directly from the upper sea layers. A new classification of gas hydrate deposits with a heterogeneous structure has been developed, which is based on the content of rocks inclusions in gas hydrate, the classification feature of which is the amount of heat spent on the dissociation process