Mechanical Behavior and Performance of the Onager

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
Arcangelo Messina ◽  
Cesare Rossi
Keyword(s):  
Mathematical Models ◽  
Mechanical Behavior ◽  
Engineering Design ◽  
Analytical Mechanics ◽  
Historical Events ◽  
Modern Times ◽  
War Machine ◽  
And Performance ◽  
Ancient Warfare ◽  
Good Agreement

In this paper, the mechanical behavior and performance of the onager, an ancient war machine, are analyzed. This study is based on torsional motors, as previously described. Because the onager has been investigated very little in modern times and the details given by ancient engineers are very scarce, this study starts from the available literature of both ancient and modern times. The mathematical models are developed through analytical mechanics along with integrations carried out numerically. Simulations performed provide interesting results which are in good agreement with the information recorded by ancient historians, and thus validating conjectures regarding the design of these machines. Finally, this investigation clarifies the role and effectiveness of these machines in ancient warfare, helping to understand many aspects of both ancient engineering design and historical events.

Standards, Codes of Practice and Expert Systems

1988 ◽  
Vol 21 (1) ◽  
pp. 5-9 ◽  
Author(s):  
E G McCluskey ◽  
S Thompson ◽  
D M G McSherry
Keyword(s):  
Expert System ◽  
Expert Systems ◽  
Engineering Design ◽  
Performance Criteria ◽  
Design Problems ◽  
Codes Of Practice ◽  
Engineering Design Problems ◽  
And Performance

Many engineering design problems require reference to standards or codes of practice to ensure that acceptable safety and performance criteria are met. Extracting relevant data from such documents can, however, be a problem for the unfamiliar user. The use of expert systems to guide the retrieval of information from standards and codes of practice is proposed as a means of alleviating this problem. Following a brief introduction to expert system techniques, a tool developed by the authors for building expert system guides to standards and codes of practice is described. The steps involved in encoding the knowledge contained in an arbitrarily chosen standard are illustrated. Finally, a typical consultation illustrates the use of the expert system guide to the standard.

scholarly journals Novel Hexagonal Dual-Mode Substrate Integrated Waveguide Filter with Source-Load Coupling

2014 ◽  
Vol 2014 ◽  
pp. 1-5
Author(s):  
Ziqiang Xu ◽  
Gen Zhang ◽  
Hong Xia ◽  
Meijuan Xu
Keyword(s):  
Center Frequency ◽  
Substrate Integrated Waveguide ◽  
Fractional Bandwidth ◽  
Dual Mode ◽  
Transmission Zeros ◽  
Cavity Structure ◽  
Waveguide Filter ◽  
And Performance ◽  
Single Cavity ◽  
Good Agreement

Hexagonal dual-mode cavity and its application to substrate integrated waveguide (SIW) filter are presented. The hexagonal SIW resonator which can combine flexibility of rectangular cavity and performance of circular cavity is convenient for dual-mode bandpass filters design. By introducing coupling between source and load, the filter not only has good selectivity due to two controllable transmission zeros, but also has a small size by the virtue of its single-cavity structure. A demonstration filter with a center frequency of 10 GHz and a 3 dB fractional bandwidth of 4% is designed and fabricated to validate the proposed structure. Measured results are in good agreement with simulated ones.

scholarly journals A. Blok and poetic strategies of postmodernism

2021 ◽  
pp. 153-160
Author(s):  
Неля Магомедовна Шишхова ◽  
Кирилл Николаевич Анкудинов
Keyword(s):  
Cultural Tradition ◽  
Actual Problem ◽  
Cultural Expression ◽  
Avant Garde ◽  
Modern Times ◽  
New Concepts ◽  
Poetic Expression ◽  
And Performance ◽  
Postmodern Poetry ◽  
Creative Forces

Анализируется поэзия А. Блока, ее взаимосвязь с реалистическими, семантическими и перфомативными аспектами творчества русских постмодернистов. Тексты рассматриваются как способ мотивирования поэтических знаков в постмодернистской традиции. Они позволяют контекстуализировать модели выразительности в авангардистской поэзии и выделить основные парадигмы в ее трактовке, адаптировать художественные приемы и поиски нового языка. Отдельное вимание уделяется особенностям поэтического высказывания и ее взаимодействию с пространством стиха. Интерес акцентируется на диалектике разрушительных и созидательных сил в деконструктивизме наследия Вс. Некрасова, Д. Пригова, Т. Кибирова и др. Обсуждается актуальная проблема для теории современной поэзии: что стало с постмодерном как языком описания эпохи в XXI столетии. Особое внимание уделяется преемственности новых концепций с предыдущей культурной традицией в негативной и позитивной версиях. Тема особенно актуализируется благодаря выраженному стремлению представить тексты А.Блока и постмодернистской поэзии как культурное выражение новейшего времени. An analysis is made of the poetry of A. Blok, its relationship with the realistic, semantic and performance aspects of the work of Russian postmodernists. Texts are explored as a way to motivate poetic signs in the postmodern tradition. They make it possible to contextualize models of expressiveness in avant-garde poetry and highlight the main paradigms in its interpretation, adapt artistic techniques and searches for a new language. An attention is paid to the peculiarities of the poetic expression and its interaction with the space of the verse. The interest is focused on the dialectic of destructive and creative forces in the deconstruction of the legacy of Vs. Nekrasov, D. Prigov, T. Kibirov, etc. The paper discusses the actual problem for the theory of modern poetry: what has become with the postmodern as the language of describing the era in the 21st century. Particular attention is paid to the continuity of new concepts with the previous cultural tradition in negative and positive versions. The theme is especially actualized due to the expressed desire to present the texts of A. Blok and postmodern poetry as a cultural expression of modern times.

scholarly journals Design of steering system of a buggy

2020 ◽  
Vol 327 ◽  
pp. 03004
Author(s):  
D. Santana Sanchez ◽  
A. Mostafa
Keyword(s):  
Carrying Capacity ◽  
Steering System ◽  
Nonlinear Finite Element ◽  
Load Carrying Capacity ◽  
Dynamic Effects ◽  
Flexural Behaviour ◽  
Steering Angle ◽  
Load Carrying ◽  
And Performance ◽  
Good Agreement

The present paper discusses the design analysis and limitations of the steering system of a buggy. Many geometrical and performance characteristics of the designed steering system were considered to address the kinematic constraints and load carrying capacity of the steering elements. Ackremann geometry approach was used to assess the limiting steering angle, while Lewis bending formula with the inclusion of dynamic effects was employed to characterise the flexural properties of the rack and pinion steering system. Analytical results were numerically verified using ABAQUS/Explicit nonlinear finite element (FE) package. Good agreement has been achieved between analytical and numerical results in predicting the flexural behaviour of the steering rack and pinion system.

scholarly journals Validation of Doppler Temperature Coefficients and Component Power Distribution for the Advanced Neutronics Component Program KYLIN V2.0

2021 ◽  
Vol 9 ◽  
Author(s):  
Lei Jichong ◽  
Xie Jinsen ◽  
Chen Zhenping ◽  
Yu Tao ◽  
Yang Chao ◽  
...  
Keyword(s):  
Engineering Design ◽  
Power Distribution ◽  
Nuclear Power ◽  
Nuclear Engineering ◽  
Temperature Coefficients ◽  
The Core ◽  
Fuel Assemblies ◽  
Design Requirements ◽  
Design Software ◽  
Good Agreement

This work is interested in verifying and analyzing the advanced neutronics assembly program KYLIN V2.0. Assembly calculations are an integral part of the two-step calculation for core design, and their accuracy directly affects the results of the core physics calculations. In this paper, we use the Doppler coefficient numerical benchmark problem and CPR1000 AFA-3G fuel assemblies to verify and analyze the advanced neutronics assembly program KYLIN V2.0 developed by the Nuclear Power Institute of China. The analysis results show that the Doppler coefficients calculated by KYLIN V2.0 are in good agreement with the results of other well-known nuclear engineering design software in the world; the power distributions of AFA-3G fuel assemblies are in good agreement with the results of the RMC calculations, it’s error distribution is in accordance with the normal distribution. It shows that KYLIN V2.0 has high calculation accuracy and meets the engineering design requirements.

Experimental and Theoretical Investigation of Performance of a Solar Chimney Model Part II: Model Development and Validation

2021 ◽  
Vol 5 (2) ◽  
Author(s):  
Ibrahim A Abuashe ◽  
Bashir H Arebi ◽  
Essaied M Shuia
Keyword(s):  
Mathematical Model ◽  
Power Output ◽  
Model Development ◽  
Geometrical Parameters ◽  
Balance Equations ◽  
Solar Chimney ◽  
And Performance ◽  
Development And Validation ◽  
The Mathematical Model ◽  
Good Agreement

A mathematical model based on the momentum, continuity and energy balance equations was developed to simulate the behavior of the air flow inside the solar chimney system. The model can estimate the power output and performance of solar chimney systems. The developed mathematical model is validated by the experimental data that were collected from small pilot solar chimney; (experiment was presented in part I). Good agreement was obtained between the experimental results and that from the mathematical model. The model can be used to analyze the solar chimney systems and to determine the effect of geometrical parameters such as chimney height and collector diameter on the power output and the efficiency of the system

scholarly journals Design, modeling, and performance analysis of a new dispensing system based on compliant mechanism

2020 ◽  
Vol 103 (2) ◽  
pp. 003685042092389
Author(s):  
Junfeng Hu ◽  
Xinying Zhao
Keyword(s):  
Life Science ◽  
Compliant Mechanism ◽  
Semiconductor Industry ◽  
Future Application ◽  
Rapid Manufacturing ◽  
Driving Voltage ◽  
Droplet Volume ◽  
Forming Process ◽  
And Performance ◽  
Good Agreement

Jet dispenser is widely used in microelectronic packaging, semiconductor industry, life science, and rapid manufacturing fields. As the requirement for dispensing accuracy and speed become higher and higher, especially for viscous materials, the traditional mechanisms cannot meet the high precision dispensing. This paper presents a new jetting dispenser using the complaint mechanism with amplifier components to design the dispenser, which gain the motion and force from the elastic deformation of flexible hinges. To describe the mechanical property of the jetting dispenser, the model of the jetting dispenser was built by employing a pseudo-rigid-body method. To predict accurately droplet volume, we established the model by describing the forming process of droplet. Furthermore, the errors of the droplet volume were analyzed based on the model. The prototype of the dispenser was built and the effects of driving voltage, radius of spray chamber, glue supply pressure, glue viscosity, and turn-on time of hammer on the droplet were analyzed experimentally. The analytical results are in good agreement with experimental results, which the advantages of the presented jetting dispenser with a new design concept are validated. This research provided a new idea and modeling method for the future application of the dispensing system.

scholarly journals Cloud Effective Emissivity Retrievals Using Combined Ground-Based Infrared Cloud Measuring Instrument and Ceilometer Observations

2018 ◽  
Vol 10 (12) ◽  
pp. 2033
Author(s):  
Lei Liu ◽  
Ting Zhang ◽  
Yi Wu ◽  
Zhencong Niu ◽  
Qi Wang
Keyword(s):  
Measuring System ◽  
Measuring Instrument ◽  
Effective Emissivity ◽  
Retrieval Method ◽  
Clear Sky ◽  
Inversion Procedure ◽  
The Mean ◽  
And Performance ◽  
Emissivity Measurements ◽  
Good Agreement

In this paper, a new inversion procedure for cloud effective emissivity retrievals using a combined ground-based infrared cloud measuring instrument with ceilometer was developed. A quantitative sensitivity and performance analysis of the proposed method was also provided. It was found that the uncertainty of the derived effective emissivity was mainly associated with errors on the measurement radiance, the simulated radiance of clear sky and blackbody cloudy sky. Furthermore, the retrieval at low effective emissivity was most sensitive to the simulated clear sky radiances, whereas the blackbody cloudy sky radiance was the prevailing source of uncertainty at high emissivity. This newly proposed procedure was applied to the measurement taken in the CMA Beijing Observatory Station from November 2011 to June 2012 by the whole-sky infrared cloud-measuring system (WSIRCMS) and CYY-2B ceilometer. The cloud effective emissivity measurements were in good agreement with that of the MODIS/AQUA MYD06 Collection 6 (C6) cloud products. The mean difference between them was 0.03, with a linear correlation coefficient of 0.71. The results demonstrate that the retrieval method is robust and reliable.

scholarly journals SRIFA: Stochastic Ranking with Improved-Firefly-Algorithm for Constrained Optimization Engineering Design Problems

Mathematics ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 250 ◽  
Author(s):  
Umesh Balande ◽  
Deepti Shrimankar
Keyword(s):  
Constrained Optimization ◽  
Engineering Design ◽  
Real World ◽  
Optimization Design ◽  
Firefly Algorithm ◽  
Optimization Problems ◽  
Design Problems ◽  
Improved Firefly Algorithm ◽  
Engineering Design Problems ◽  
And Performance

Firefly-Algorithm (FA) is an eminent nature-inspired swarm-based technique for solving numerous real world global optimization problems. This paper presents an overview of the constraint handling techniques. It also includes a hybrid algorithm, namely the Stochastic Ranking with Improved Firefly Algorithm (SRIFA) for solving constrained real-world engineering optimization problems. The stochastic ranking approach is broadly used to maintain balance between penalty and fitness functions. FA is extensively used due to its faster convergence than other metaheuristic algorithms. The basic FA is modified by incorporating opposite-based learning and random-scale factor to improve the diversity and performance. Furthermore, SRIFA uses feasibility based rules to maintain balance between penalty and objective functions. SRIFA is experimented to optimize 24 CEC 2006 standard functions and five well-known engineering constrained-optimization design problems from the literature to evaluate and analyze the effectiveness of SRIFA. It can be seen that the overall computational results of SRIFA are better than those of the basic FA. Statistical outcomes of the SRIFA are significantly superior compared to the other evolutionary algorithms and engineering design problems in its performance, quality and efficiency.

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