scholarly journals A 4-node quadrilateral element with center-point based discrete shear gap (CP-DSG4)

Author(s):  
Minh Nguyen ◽  
Tinh Quoc Bui ◽  
Vay Siu Lo ◽  
Nha Thanh Nguyen

This work aims at presenting a novel four-node quadrilateral element, which is enhanced by integrating with discrete shear gap (DSG), for analysis of Reissner-Mindlin plates. In contrast to previous studies that are mainly based on three-node triangular elements, here we, for the first time, extend the DSG to four-node quadrilateral elements. We further integrate the fictitious point located at the center of element into the present formulation to eliminate the so-called anisotropy, leading to a simplified and efficient calculation of DSG, and that enhancement results in a novel approach named as "four-node quadrilateral element with center-point based discrete shear gap - CP-DSG4". The accuracy and efficiency of the CP-DSG4 are demonstrated through our numerical experiment, and its computed results are validated against those derived from the three-node triangular element using DSG, and other existing reference solutions.

2012 ◽  
Vol 157-158 ◽  
pp. 1093-1096
Author(s):  
Hui Hua Zhang ◽  
Jia Xiang Yan

The numerical manifold method (NMM) is a representative among different numerical methods for crack problems. Due to the independence of physical domain and the mathematical cover system, totally regular mathematical elements can be used in the NMM. In the present paper, the NMM is applied to solve 2-D linear elastic crack problems, together with the comparison study on the accuracy of n-sided regular mathematical elements, i.e., the triangular elements (n=3), the quadrilateral elements (n=4) and the hexagonal elements (n=6). Our numerical results show that among different elements, the regular hexagonal element is the best and the quadrilateral element is better than the triangular one.


2018 ◽  
Vol 15 (06) ◽  
pp. 1850056 ◽  
Author(s):  
T. Nguyen-Thoi ◽  
T. Bui-Xuan ◽  
G. R. Liu ◽  
T. Vo-Duy

A cell-based smoothed discrete shear gap method (CS-FEM-DSG3) using three-node triangular element was recently proposed for static, free vibration and buckling analyses of stiffened Mindlin plates. The CS-FEM-DSG3 element is a significant improvement of the original DSG3 element by using smoothing technique to soften the stiffness of the DSG3 element while it has still inherited the locking-free feature of the former. In this paper, the CS-FEM-DSG3 is further extended for the static and free vibration analyses of stiffened flat shells by combining the original plate element CS-FEM-DSG3 with Allman’s plane stress element and a linearly isotropic two-node stiffened beam element. The compatibility of displacement field of stiffeners and shell is applied at the contact positions. Numerical results of the proposed element are compared with those of some existing methods to demonstrate the accuracy and reliability of the proposed method.


2021 ◽  
Vol 11 (9) ◽  
pp. 4241
Author(s):  
Jiahua Wu ◽  
Hyo Jong Lee

In bottom-up multi-person pose estimation, grouping joint candidates into the appropriately structured corresponding instance of a person is challenging. In this paper, a new bottom-up method, the Partitioned CenterPose (PCP) Network, is proposed to better cluster the detected joints. To achieve this goal, we propose a novel approach called Partition Pose Representation (PPR) which integrates the instance of a person and its body joints based on joint offset. PPR leverages information about the center of the human body and the offsets between that center point and the positions of the body’s joints to encode human poses accurately. To enhance the relationships between body joints, we divide the human body into five parts, and then, we generate a sub-PPR for each part. Based on this PPR, the PCP Network can detect people and their body joints simultaneously, then group all body joints according to joint offset. Moreover, an improved l1 loss is designed to more accurately measure joint offset. Using the COCO keypoints and CrowdPose datasets for testing, it was found that the performance of the proposed method is on par with that of existing state-of-the-art bottom-up methods in terms of accuracy and speed.


Author(s):  
Mirjam Stocker ◽  
Gerda Schneider ◽  
Julia Zeilinger ◽  
Gloria Rose ◽  
Doris Damyanovic ◽  
...  

AbstractHousing plays a central role in everyday life and the fulfillment of human needs. Temporary housing demand can occur due to migration, extreme environmental events or personal decisions, and is expected to increase in the upcoming years. This study aims to create a general understanding of temporary housing. We conducted an integrated comparison of 66 international temporary housing examples via tabulation (table work), in an interdisciplinary manner considering details regarding built structure, open spaces, area, infrastructure, organizational and socio-economic aspects. It is the first time that a systematic comparison via tabulation (based on the approach of Braun-Blanquet) is used to classify temporary housing environments. The process is described in detail. The application of the systematic comparison creates a detailed typology that allows extensions and further differentiations. The types that emerge from the tabulation have specific concepts regarding the structural-spatial organization, technical infrastructure, and organizational matters, among others. The typology was further examined in the context of previous groupings in published literature. This novel approach of analyzing and structuring temporary housing offers a comprehensive perspective that can work as a universal understanding and language for precise communication among different disciplines regarding temporary housing.


2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Yu Zheng ◽  
Xudong Luo ◽  
Jinlong Yang ◽  
Wenlong Huo ◽  
Chi Kang

A novel approach is used for fabricating steel slag foam ceramics based on the particle-stabilized foaming method. In this work, steel slag was used as the raw material and propyl gallate (PG) was used as the surface modifier. For the first time, steel slag ceramic foams were successfully fabricated based on particle-stabilized foams. The results show that the stability of the ceramic foams was closely related to the pH value and PG concentration. The porosity and compressive strength could be controlled by changing the solid loading of steel slag and sintering temperature. The porosity of steel slag foam ceramics ranged from 85.6% to 62.53%, and the compressive strength was from 1.74 MPa to 10.42 MPa. The thermal conductivity of steel slag foam ceramics was only 0.067 W (m·K)−1, which shows that it could be used as a thermal insulation material.


2017 ◽  
Vol 41 (4) ◽  
pp. 599-603 ◽  
Author(s):  
Enver Ahmet Demir ◽  
Okan Tutuk ◽  
Hatice Dogan ◽  
Duygu Egeli ◽  
Cemil Tumer

The educators have underlined the importance of lecture attendance for decades. Nowadays, students have ample online educational sources, which began a debate on the necessity of in-class lectures. In the present study, we investigated the influence of lecture attendance on the exam success. To this aim, we adopted a novel approach and matched second-year medicine students’ answers in three interim exams with the lectures related to those questions. Thereby, we were able to evaluate if attending lectures increases the chance of giving a correct answer to the exam question generated from the attended lecture. Furthermore, we examined students who had never taken the course before (first-time takers) and students who had failed and repeated the course (repeat takers) separately, since repeat takers may have attended a lecture previously. We found that first-time takers attended more lectures and gained higher total scores than repeat takers. Lecture-matched correct answers were significantly higher for attended lectures than for skipped lectures in all interim exams. Moreover, the correlation analyses revealed that the number of correct answers increases by lecture attendance in both first-time and repeat takers. These results indicate that in-class lectures still should be considered as an essential part of the medical physiology education, even in the internet era.


2019 ◽  
Vol 17 (03) ◽  
pp. 1850133 ◽  
Author(s):  
T. Truong-Thi ◽  
T. Vo-Duy ◽  
V. Ho-Huu ◽  
T. Nguyen-Thoi

This study presents an extension of the cell-based smoothed discrete shear gap method (CS-DSG3) using three-node triangular elements for the static and free vibration analyses of carbon nanotube reinforced composite (CNTRC) plates. The single-walled carbon nanotubes (SWCNTs) are assumed to be uniformly distributed (UD) and functionally graded (FG) distributed along the thickness direction. The material properties of carbon nanotube-reinforced composite plates are estimated according to the rule of mixture. The governing equations are developed based on the first-order shear deformation plate theory (FSDT). In the CS-DSG3, each triangular element will be divided into three sub-triangles, and in each sub-triangle, the stabilized discrete shear gap method is used to compute the strains and to avoid the transverse shear locking. Then the strain smoothing technique on the whole triangular element is used to smooth the strains on these three sub-triangles. Effects of several parameters, such as the different distribution of carbon nanotubes (CNTs), nanotube volume fraction, boundary condition and width-to-thickness ratio of plates are investigated. In addition, the effect of various orientation angles of CNTs is also examined in detail. The accuracy and reliability of the proposed method are verified by comparing its numerical solutions with those of other available results in the literature.


2013 ◽  
Vol 13 (15) ◽  
pp. 7875-7894 ◽  
Author(s):  
I. El Haddad ◽  
B. D'Anna ◽  
B. Temime-Roussel ◽  
M. Nicolas ◽  
A. Boreave ◽  
...  

Abstract. As part of the FORMES summer 2008 experiment, an Aerodyne compact time-of-flight aerosol mass spectrometer (cToF-AMS) was deployed at an urban background site in Marseille to investigate the sources and aging of organic aerosols (OA). France's second largest city and the largest port in the Mediterranean, Marseille, provides a locale that is influenced by significant urban industrialized emissions and an active photochemistry with very high ozone concentrations. Particle mass spectra were analyzed by positive matrix factorization (PMF2) and the results were in very good agreement with previous apportionments obtained using a chemical mass balance (CMB) approach coupled to organic markers and metals (El Haddad et al., 2011a). AMS/PMF2 was able to identify for the first time, to the best of our knowledge, the organic aerosol emitted by industrial processes. Even with significant industries in the region, industrial OA was estimated to contribute only ~ 5% of the total OA mass. Both source apportionment techniques suggest that oxygenated OA (OOA) constitutes the major fraction, contributing ~ 80% of OA mass. A novel approach combining AMS/PMF2 data with 14C measurements was applied to identify and quantify the fossil and non-fossil precursors of this fraction and to explicitly assess the related uncertainties. Results show with high statistical confidence that, despite extensive urban and industrial emissions, OOA is overwhelmingly non-fossil, formed via the oxidation of biogenic precursors, including monoterpenes. AMS/PMF2 results strongly suggest that the variability observed in the OOA chemical composition is mainly driven in our case by the aerosol photochemical age. This paper presents the impact of photochemistry on the increase of OOA oxygenation levels, formation of humic-like substances (HULIS) and the evolution of α-pinene SOA (secondary OA) components.


ZDM ◽  
2021 ◽  
Author(s):  
Gert Schubring

AbstractThe aspiration of this paper is to develop a novel approach towards investigating the socio-political history of mathematics teaching in educational systems. Traditionally, historical studies are confined to just one country, the author’s country. Broader approaches address international developments by confronting and comparing global and local aspects—revealing general patterns and more specific ‘local’ structures and characteristics. Yet, already in antiquity and medieval times, the specific characteristic of mathematics teaching, namely to operate at the crossroads of general education and vocational training, proved to be intimately tied to the functioning of the particular political system. In pre-modern times, however, a truly international pattern emerged for the first time: European powers conquered, occupied and colonised overseas regions. Given that educational systems were emerging at the same time within these states, they often transmitted elements of these structures to their colonies. This phenomenon included mathematics, and the history of its teaching is analysed here as a part of coloniality. It is shown that this was not a uniform process, and the differences between the various colonial powers are discussed. The involvement of mathematics in the process of decolonisation is addressed, as well as its role in the tension between continued coloniality and movements of decoloniality. Finally, the general framework provided for studying socio-political processes connected with establishing mathematics teaching within public educational systems is applied, in order to analyse recent coloniality practices effected by international achievement studies.


1983 ◽  
Vol 37 ◽  
pp. 10-12
Author(s):  
Kent Morrison

What to teach the first-time student in a political science class? Perhaps more importantly, what to teach the undergraduate whose only experience with political science, and the formal study of politics, will be the introduction they receive in our classes?Owing to the peculiarities of our discipline, the “Introduction to Political Science” class is often just that: a tour through all the major gardens in the discipline, describing to students what is done among scholars and practicioners in the various fields, giving them an overall view of what we do, how we do it, and in the process perhaps making a case for the significance of our discipline, our research, and perhaps even the subject itself — politics.


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