scholarly journals Simple Method of Approximate Calculation of Statically Indeterminate Trusses

2019 ◽  
Vol 16 (06) ◽  
pp. 1840026 ◽  
Author(s):  
Janusz Rębielak
Keyword(s):  
Approximate Calculation ◽  
Computer Software ◽  
Two Stage ◽  
Simple Method ◽  
Two Stages

The paper presents principles of the simple method which makes possible approximate calculations of statically indeterminate truss systems in two stages. The two-stage method applies rules of other methods used for calculations of statically determinate trusses. In each of the two stages, there are considered statically determinate trusses, patterns of which are obtained as results of suitable withdrawing of appropriate members from the pattern of the basic statically indeterminate truss. There are presented results of calculations carried out for two cases of load for selected type of plane truss together with comparison of outcomes obtained by means of using appropriate computer software.

scholarly journals Two-Stage Method Applied for Approximate Calculations of Selected Types of Statically Indeterminate Trusses

2020 ◽  
pp. 2041004
Author(s):  
Janusz Rȩbielak
Keyword(s):  
Approximate Calculation ◽  
Computer Software ◽  
Two Stage

The paper presents examples of approximate calculations of force values in members of selected types of trusses, which are at the same time an internal and external statically indeterminate systems. The two-stage method makes possible the approximate calculation of such trusses by help of, for example, the Cremona’s method. In each stage, a statically determinate truss is considered, pattern of which is defined by removing from the basic truss a suitable number of members. There are also presented results of calculations of the same trusses done by means of suitable computer software together with analyses and comparison of outcomes.

A novel two-stage method of plant seedlings classification based on deep learning

2021 ◽  
pp. 1-11
Author(s):  
Tianhong Dai ◽  
Shijie Cong ◽  
Jianping Huang ◽  
Yanwen Zhang ◽  
Xinwang Huang ◽  
...  
Keyword(s):  
Deep Learning ◽  
Learning Technology ◽  
Two Stage ◽  
Second Stage ◽  
Stage Classification ◽  
Different Types ◽  
Two Stages ◽  
Plant Seedlings

In agricultural production, weed removal is an important part of crop cultivation, but inevitably, other plants compete with crops for nutrients. Only by identifying and removing weeds can the quality of the harvest be guaranteed. Therefore, the distinction between weeds and crops is particularly important. Recently, deep learning technology has also been applied to the field of botany, and achieved good results. Convolutional neural networks are widely used in deep learning because of their excellent classification effects. The purpose of this article is to find a new method of plant seedling classification. This method includes two stages: image segmentation and image classification. The first stage is to use the improved U-Net to segment the dataset, and the second stage is to use six classification networks to classify the seedlings of the segmented dataset. The dataset used for the experiment contained 12 different types of plants, namely, 3 crops and 9 weeds. The model was evaluated by the multi-class statistical analysis of accuracy, recall, precision, and F1-score. The results show that the two-stage classification method combining the improved U-Net segmentation network and the classification network was more conducive to the classification of plant seedlings, and the classification accuracy reaches 97.7%.

The Occurrence of Meniscal and Chondral Injury in Two-Stage Revision Anterior Cruciate Ligament Reconstruction: A Consecutive Case Series

2019 ◽  
Vol 33 (03) ◽  
pp. 223-227
Author(s):  
Floris R. van Tol ◽  
Willem A. Kernkamp ◽  
Robert J. P. van der Wal ◽  
Jan-Willem A. Swen ◽  
Samuel K. Van de Velde ◽  
...  
Keyword(s):  
Anterior Cruciate Ligament ◽  
Acl Reconstruction ◽  
Cruciate Ligament ◽  
Meniscal Tear ◽  
Partial Meniscectomy ◽  
Two Stage ◽  
Revision Acl Reconstruction ◽  
Chondral Injury ◽  
Anterior Cruciate ◽  
Two Stages

AbstractTwo-stage revision anterior cruciate ligament (ACL) reconstruction is an effective way to revise suboptimal tunnel-placement allowing for proper graft fixation. However, prolonged increased laxity of the knee may increase the risk of meniscal or chondral injury. It was hypothesized that no additional meniscal or chondral lesions occur in between the two stages of the two-stage revision ACL reconstruction. In this retrospective study, 42 patients undergoing a two-stage revision ACL reconstruction were included. Surgical notes for both stages were screened for meniscal and chondral status, interventions to any concurrent injury, surgery dates, along with basic patient characteristics. In 4 of the 42 patients, a new meniscal tear occurred in between the two stages, of which three required partial meniscectomy during the second stage of the ACL revision. One patient experienced a new small degenerative tear that did not require intervention. Two out of the four menisci that were repaired during the first stage had failed and required partial meniscectomy. No significant difference was found in the time between the two stages with respect to the occurrence of meniscal tears. No significant differences in chondral status were found. In conclusion, approximately 10% of patients developed a new meniscal tear and no difference in macroscopic chondral injury was observed between the first and second stages.

Research on City 3D Modeling and Application Based on Skyline

2012 ◽  
Vol 594-597 ◽  
pp. 2394-2397
Author(s):  
Jian Cui ◽  
Dong Ling Ma ◽  
Fei Cai
Keyword(s):  
Urban Design ◽  
Computer Technology ◽  
Traditional Method ◽  
3D Visualization ◽  
Rapid Development ◽  
Three Dimensional ◽  
Computer Software ◽  
Communications Technology ◽  
Digital City ◽  
Simple Method

With the rapid development of computer technology, communications technology, and other related technologies, the Digital City has become a hot topic of current research. The traditional method of constructing digital city based on ArcGis is very complex, the type of computer software that related is much more, and the interaction between the software is poor. For the traditional method of digital urban design is difficult to design and visualization effect is poor, this paper builds the techniques of campus apartment modeling based on the skyline combined specific examples of campus apartments, realizes three dimensional (3D) visualization and query and analysis functions of the campus apartment system and proposes a simple method of creating 3D landscape efficiently.

scholarly journals Two-Stage Late Jurassic to Early Cretaceous Hydrothermal Activity in the Sakar Unit of Southeastern Bulgaria

Minerals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 266
Author(s):  
Krzysztof Szopa ◽  
Anna Sałacińska ◽  
Ashley P. Gumsley ◽  
David Chew ◽  
Petko Petrov ◽  
...  
Keyword(s):  
Early Cretaceous ◽  
Late Jurassic ◽  
Hydrothermal Activity ◽  
Two Stage ◽  
Accessory Minerals ◽  
Icp Ms ◽  
Two Stages ◽  
Age Constraints ◽  
Hydrothermal Veins

Southeastern Bulgaria is composed of a variety of rocks from pre-Variscan (ca. 0.3 Ga) to pre-Alpine sensu lato (ca. 0.15 Ga) time. The Sakar Unit in this region comprises a series of granitoids and gneisses formed or metamorphosed during these events. It is cut by a series of post-Variscan hydrothermal veins, yet lacks pervasive Alpine deformation. It thus represents a key unit for detecting potential tectonism associated with the enigmatic Cimmerian Orogenic episode, but limited geochronology has been undertaken on this unit. Here we report age constraints on hydrothermal activity in the Sakar Pluton. The investigated veins contain mainly albite–actinolite–chlorite–apatite–titanite–quartz–tourmaline–epidote and accessory minerals. The most common accessory minerals are rutile and molybdenite. Apatite and titanite from the same vein were dated by U–Pb LA–ICP-MS geochronology. These dates are interpreted as crystallization ages and are 149 ± 7 Ma on apatite and 114 ± 1 Ma on titanite, respectively. These crystallization ages are the first to document two stages of hydrothermal activity during the late Jurassic to early Cretaceous, using U–Pb geochronology, and its association with the Cimmerian orogenesis. The Cimmerian tectono-thermal episode is well-documented further to the east in the Eastern Strandja Massif granitoids. However, these are the first documented ages from the western parts of the Strandja Massif, in the Sakar Unit. These ages also temporally overlap with previously published Ar–Ar and K–Ar cooling ages, and firmly establish that the Cimmerian orogeny in the studied area included both tectonic and hydrothermal activity. Such hydrothermal activity likely accounted for the intense albitization found in the Sakar Unit.

scholarly journals Performance Analysis and Working Fluid Selection for Single and Two Stages Vapor Compression Refrigeration Cycles

Processes ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1017
Author(s):  
Bahaa Saleh ◽  
Ayman A. Aly ◽  
Mishal Alsehli ◽  
Ashraf Elfasakhany ◽  
Mohamed M. Bassuoni
Keyword(s):  
Energy Efficiency ◽  
Environmental Impacts ◽  
High Energy ◽  
Working Fluid ◽  
Vapor Compression ◽  
Alternative Refrigerants ◽  
Two Stage ◽  
Azeotropic Mixtures ◽  
Vapor Compression Refrigeration ◽  
Two Stages

Screening for alternative refrigerants with high energy efficiency and low environmental impacts is one of the highest challenges of the refrigeration sector. This paper investigates the performance and refrigerant screening for single and two stages vapor compression refrigeration cycles. Several pure hydrocarbons, hydrofluorocarbons, hydrofluoroolefins, fluorinated ethers, and binary azeotropic mixtures are proposed as alternative refrigerants to substitute R22 and R134a due to their environmental impacts. The BACKONE equation of state is used to compute the thermodynamic properties of the candidates. The results show that the maximum coefficients of performance (COP) for single and two stage cycles using pure substances are achieved using cyclopentane with values of 4.14 and 4.35, respectively. On the other side, the maximum COP for the two cycles using azeotropic mixtures is accomplished using R134a + RE170 with values of 3.96 and 4.27, respectively. The two-stage cycle presents gain in COP between 5.1% and 19.6% compared with the single-stage cycle based on the used refrigerant. From the obtained results, among all investigated refrigerants, cyclopentane is the most suitable refrigerant for the two cycles from the viewpoint of energy efficiency. However, extra cautions should be taken due to its flammability.

scholarly journals High-Performance Parallel Simulation of Airflow for Complex Terrain Surface

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Kenji Ono ◽  
Takanori Uchida
Keyword(s):  
Mesh Generation ◽  
High Performance ◽  
Power Plants ◽  
Domain Decomposition Method ◽  
Simulation Method ◽  
Two Stage ◽  
Hybrid Parallelization ◽  
Strong Scaling ◽  
Computing Performance ◽  
Two Stages

It is important to develop a reliable and high-throughput simulation method for predicting airflows in the installation planning phase of windmill power plants. This study proposes a two-stage mesh generation approach to reduce the meshing cost and introduces a hybrid parallelization scheme for atmospheric fluid simulations. The meshing approach splits mesh generation into two stages: in the first stage, the meshing parameters that uniquely determine the mesh distribution are extracted, and in the second stage, a mesh system is generated in parallel via an in situ approach using the parameters obtained in the initialization phase of the simulation. The proposed two-stage approach is flexible since an arbitrary number of processes can be selected at run time. An efficient OpenMP-MPI hybrid parallelization scheme using a middleware that provides a framework of parallel codes based on the domain decomposition method is also developed. The preliminary results of the meshing and computing performance show excellent scalability in the strong scaling test.

scholarly journals Three-Dimensional Modeling and Structured Vibration Modes of Two-Stage Helical Planetary Gears Used in Cranes

2017 ◽  
Vol 2017 ◽  
pp. 1-18 ◽  
Author(s):  
Lina Zhang ◽  
Yong Wang ◽  
Kai Wu ◽  
Ruoyu Sheng
Keyword(s):  
Three Dimensional ◽  
Structure Design ◽  
Parameter Method ◽  
Vibration Modes ◽  
Two Stage ◽  
Planetary Gears ◽  
Three Dimensional Modeling ◽  
Translational Mode ◽  
Gyroscopic Effects ◽  
Two Stages

The dynamic investigation of helical planetary gears plays an important role in structure design as the vibration and noise are perceived negatively to the transmission quality. With consideration of the axial deformations of members, the gyroscopic effects, the time-variant meshing stiffness, and the coupling amongst stages, a three-dimensional dynamic model of the two-stage helical planetary gears is established by using of the lumped-parameter method in this paper. The model is applicable to variant number of planets in two stages, different planet phasing, and spacing configurations. Numerical simulation is conducted to detect the structured vibration modes of the equally spaced systems. Furthermore, the unique properties of these vibration modes are mathematically proved. Results show that the vibration modes of the two-stage helical planetary gears can be categorized as five classes: the rigid body mode, the axial translational-rotational mode, the radical translational mode, and the 1st-stage and the 2nd-stage planet mode.

A Two-Stage Model of Tenure Mobility

1978 ◽  
Vol 10 (1) ◽  
pp. 81-92 ◽  
Author(s):  
C Jones ◽  
S Gudjonsson ◽  
J Parry Lewis
Keyword(s):  
Discriminant Analysis ◽  
Residential Mobility ◽  
Life Style ◽  
Stage Model ◽  
Multiple Discriminant Analysis ◽  
Two Stage ◽  
Socioeconomic Characteristics ◽  
Decisionmaking Process ◽  
Two Stages ◽  
Sequential Nature

This paper examines the sequential nature of the residential-mobility decisionmaking process. Initially a model of household tenure mobility is considered, consisting of two stages, the decision to move and the choice of tenure; ultimately this assumption is relaxed. Multiple discriminant analysis is used to distinguish between the different groups of households, between movers and nonmovers, and between different tenures, on the basis of a set of variables describing the socioeconomic characteristics of the household. Life-style and demographic factors are shown to influence more the tenure moved to than the decision to move. And although various factors appear to influence the mobility decision in the different tenures, the age of the household is generally found to be the most important discriminator.

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