Multiply Separated Position Design of the Geared Five-Bar Function Generator

1971 ◽  
Vol 93 (1) ◽  
pp. 74-84 ◽  
Author(s):  
S. A. Oleksa ◽  
D. Tesar
Keyword(s):  
Design Parameters ◽  
Function Generator ◽  
Function Generation ◽  
Four Bar Linkage ◽  
Generation Problem ◽  
Made In

The geared five-bar linkage is the foundation for a function generation problem meeting specifications for 5 multiply separated positions and containing 4 free design parameters. The four-bar linkage is shown to be a member of this class of mechanisms. Design examples of rarely treated functions are given with the quality of the generated approximation. Suggestions are made in terms of the 4 design parameters to assist the designer in obtaining good results.

Tolerance Design for Four-Bar Function Generating Mechanisms with Joint Clearances Using Taguchi Method

2010 ◽  
Vol 118-120 ◽  
pp. 517-521 ◽  
Author(s):  
Xian Zhen Huang ◽  
Yi Min Zhang ◽  
Hao Lu ◽  
Le Tang ◽  
He Li
Keyword(s):  
Taguchi Method ◽  
Design Parameters ◽  
Tolerance Design ◽  
Function Generator ◽  
Function Generation ◽  
Joint Clearances ◽  
Generation Mechanisms ◽  
Sensitivity Maps

This paper presents a method for tolerance design of four-bar function generating mechanisms with joint clearances using Taguchi method. Based on previous studies made by other researchers, we propose a model to quantify the effects of uncertain factors on the accuracy of four-bar function generating mechanisms. Taguchi’s approach is applied to select the optimal tolerance ranges for the design parameters of function generation mechanisms. Sensitivity maps are plotted to provide an insight to the effects of parameter errors on the performance variances of four-bar function generating mechanisms. To illustrate the efficiency of the proposed methodology, the tolerance design of a four-bar function generator with joint clearances is discussed.

Dynamic Analysis of a Ramp-Roller Clutch

1997 ◽  
Author(s):  
Chin-Tzung Chang ◽  
Ali A. Seireg
Keyword(s):  
Dynamic Analysis ◽  
Dynamic Behavior ◽  
Arbitrary Function ◽  
Settling Time ◽  
Phase Shifting ◽  
Design Parameters ◽  
Mechanical Function ◽  
Function Generator ◽  
Function Generation ◽  
Damping Characteristics

Abstract This study deals with the design and dynamic analysis of a ramp-roller clutch which can be utilized in developing a mechanical function generator. The dynamic behavior with non-linear torsional spring and damping characteristics is first investigated. Three major design parameters are identified and further optimized for the objective of minimizing the settling time. As a result of underdamping, undesired vibration can occur during the engagement. In order to minimize these unwanted vibrations, coulomb dampers are considered. By adding a properly tuned auxiliary damper, the settling time can be significantly reduced. An example is also given to illustrate the use of one-directional clutches for mechanical function generation where an arbitrary function is synthesized by sequentially triggering 7 clutches. Phase shifting is incorporated in the to reduce the error in the generated function.

Synthesis of Four-Bar Linkage Function Generators by Means of Equations of Motion

1965 ◽  
Vol 87 (2) ◽  
pp. 170-176 ◽  
Author(s):  
C. K. Wojcik
Keyword(s):  
Equations Of Motion ◽  
Angular Acceleration ◽  
Input Output ◽  
Connecting Rod ◽  
Function Generator ◽  
Function Generation ◽  
Function Generators ◽  
Two Parameters ◽  
Four Bar Linkage ◽  
Selection Of

The function generation method presented in this paper is based on consideration of the equations of motion of a four-bar linkage with an assumed input of θ˙1 = 1 rad/sec. For a specified input-output relationship, the task of synthesizing an appropriate four-bar linkage is reduced by this method to a problem of selecting two parameters: θ˙2—the angular velocity and θ¨2—the angular acceleration of the connecting rod. The selection of these parameters is governed by certain conditions imposed on the performance of the four-bar linkage function generator. Using this method, two specific problems are solved and discussed in detail.

Reuse of Sludge from Pulp and Paper Industry Pilot and Full Scale Applications

1993 ◽  
Vol 28 (2) ◽  
pp. 17-26 ◽  
Author(s):  
V. Eroǧlu ◽  
A. M. Saatçi
Keyword(s):  
Economic Analysis ◽  
Paper Industry ◽  
Pulp And Paper Industry ◽  
Pulp And Paper ◽  
Full Scale ◽  
Primary Sludge ◽  
Recent Advances ◽  
Made In

Recent advances made in the reuse of pulp and paper industry sludges in hardboard production are explained. Data obtained from pilot and full-scale plants using primary sludge of a pulp and paper industry as an additive in the production of hardboard is presented. An economic analysis of the reuse of pulp and paper primary sludge in hardboard manufacturing is given. The quality of the hardboard produced is tested and compared with the qualities of the hardboard produced by the same plant before the addition of primary sludge. The hardboard with primary sludge additive has been used in Turkey for about a year in the manufacturing of office and home furniture. The results are very satisfactory when the primary sludge is used at 1/4 ratio.

Up-flow roughing filtration: rehabilitation of a water treatment plant in Tarata, Bolivia

1998 ◽  
Vol 37 (9) ◽  
pp. 105-112 ◽  
Author(s):  
Ana María Ingallinella ◽  
Luis María Stecca ◽  
Martin Wegelin
Keyword(s):  
Water Treatment ◽  
Pilot Plant ◽  
Laboratory Tests ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Horizontal Flow ◽  
Design Parameters ◽  
Sand Filters ◽  
Chemical Products ◽  
Made In

This paper presents the methodology used for the rehabilitation of the pretreatment stage in a water treatment plant for a village located in Bolivia which has 3500 inhabitants. The treatment plant was initially composed by horizontal-flow roughing filters and slow sand filters, but due to the high contents of colloidal turbidity of the providing source, it did not work properly. A plan of rehabilitation was made which comprised laboratory tests, pilot tests and proposal of modifications based on the results of previous stages. The laboratory tests were made in order to find the optimum conditions to coagulate the raw water. It was found that horizontal-flow roughing filters must be turned into up-flow roughing filters, so a pilot plant was built and was operated for three months in order to find suitable design parameters. The results obtained obtained during the operation of the pilot plant and the proposal of modifications are presented. The results of operation of the final plant, which are also reported, demonstrated the advantages of the up-flow roughing filtration as a pretreatment stage when it is necessary to add chemical products in small treatment plants.

DIAGNOSING QUALITY OF FRICTION SYSTEMS OF MECHANISMS OF DEVICES

2019 ◽  
Vol 1 (7) ◽  
pp. 10-13
Author(s):  
D. Yu. Ershov ◽  
I. N. Lukyanenko ◽  
E. E. Aman
Keyword(s):  
Surface Defects ◽  
Diagnostic Methods ◽  
Design Parameters ◽  
Diagnostic Model ◽  
Mechanical Assemblies ◽  
Local Defects ◽  
Relationship Of ◽  
The Relationship ◽  
Production And Operation

The article shows the need to develop diagnostic methods for monitoring the quality of lubrication systems, which makes it possible to study the dynamic processes of contacting elements of the friction systems of instrument mechanisms, taking into account roughness parameters, the presence of local surface defects of elements and the bearing capacity of a lubricant. In the present article, a modern diagnostic model has been developed to control the quality of the processes of production and operation of friction systems of instrument assemblies. With the help of the developed model, it becomes possible to establish the relationship of diagnostic and design parameters of the mechanical system, as well as the appearance of possible local defects and lubricant state, which characterize the quality of friction systems used in many mechanical assemblies of the mechanisms of devices. The research results are shown in the form of nomograms to assess the defects of the elements of friction mechanisms of the mechanisms of the devices.

scholarly journals Determination of Environmental Factors for the Implementation of the Exploitability Index in Industrial Aggregate Mining Using Multi-Criteria Analysis

2021 ◽  
Vol 10 (4) ◽  
pp. 196
Author(s):  
Julio Manuel de Luis-Ruiz ◽  
Benito Ramiro Salas-Menocal ◽  
Gema Fernández-Maroto ◽  
Rubén Pérez-Álvarez ◽  
Raúl Pereda-García
Keyword(s):  
Environmental Factors ◽  
Environmental Factor ◽  
Human Life ◽  
Accurate Estimation ◽  
Analytic Hierarchy ◽  
Main Components ◽  
Hierarchy Process ◽  
Made In

The quality of human life is linked to the exploitation of mining resources. The Exploitability Index (EI) assesses the actual possibilities to enable a mine according to several factors. The environment is one of the most constraining ones, but its analysis is made in a shallow way. This research is focused on its determination, according to a new preliminary methodology that sets the main components of the environmental impact related to the development of an exploitation of industrial minerals and its weighting according to the Analytic Hierarchy Process (AHP). It is applied to the case of the ophitic outcrops in Cantabria (Spain). Twelve components are proposed and weighted with the AHP and an algorithm that allows for assigning a normalized value for the environmental factor to each deposit. Geographic Information Systems (GISs) are applied, allowing us to map a large number of components of the environmental factors. This provides a much more accurate estimation of the environmental factor, with respect to reality, and improves the traditional methodology in a substantial way. It can be established as a methodology for mining spaces planning, but it is suitable for other contexts, and it raises developing the environmental analysis before selecting the outcrop to be exploited.

scholarly journals Downregulation of exosomal let-7d and miR-16 in idiopathic pulmonary fibrosis

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Donato Lacedonia ◽  
Giulia Scioscia ◽  
Piera Soccio ◽  
Massimo Conese ◽  
Lucia Catucci ◽  
...  
Keyword(s):  
Idiopathic Pulmonary Fibrosis ◽  
Pulmonary Fibrosis ◽  
Therapy Response ◽  
Down Regulation ◽  
Cross Sectional ◽  
Exosomal Mirnas ◽  
Different Types ◽  
Sectional Analysis ◽  
Made In

Abstract Background Idiopathic Pulmonary Fibrosis (IPF) is a degenerative interstitial lung disease with both a poor prognosis and quality of life once the diagnosis is made. In the last decade many features of the disease have been investigated to better understand the pathological steps that lead to the onset of the disease and, moreover, different types of biomarkers have been tested to find valid diagnostic, prognostic and therapy response predictive ones. In the complexity of IPF, microRNA (miRNAs) biomarker investigation seems to be promising. Methods We analysed the expression of five exosomal miRNAs supposed to have a role in the pathogenesis of the disease from serum of a group of IPF patients (n = 61) and we compared it with the expression of the same miRNAs in a group of healthy controls (n = 15). Results In the current study what emerged is let-7d down-regulation and, unexpectedly, miR-16 significant down-regulation. Moreover, through a cross-sectional analysis, a clustering of the expression of miR-16, miR-21 and miR-26a was found. Conclusions These findings could help the individuation of previously unknown key players in the pathophysiology of IPF and, most interestingly, more specific targets for the development of effective medications.

Arthroscopic International Cartilage Repair Society Classification System Has Only Moderate Reliability in a Porcine Cartilage Repair Model

2021 ◽  
pp. 036354652199800
Author(s):  
Jani Puhakka ◽  
Teemu Paatela ◽  
Eve Salonius ◽  
Virpi Muhonen ◽  
Anna Meller ◽  
...  
Keyword(s):  
Cartilage Repair ◽  
Scoring System ◽  
Femoral Condyle ◽  
Intraclass Correlation ◽  
Type Iii Collagen ◽  
Intrarater Reliability ◽  
Scoring Method ◽  
International Cartilage Repair Society ◽  
Made In

Background: The International Cartilage Repair Society (ICRS) score was designed for arthroscopic use to evaluate the quality of cartilage repair. Purpose: To evaluate the reliability of the ICRS scoring system using an animal cartilage repair model. Study Design: Controlled laboratory study. Methods: A chondral defect with an area of 1.5 cm2 was made in the medial femoral condyle of 18 domestic pigs. Five weeks later, 9 pigs were treated using a novel recombinant human type III collagen/polylactide scaffold, and 9 were left to heal spontaneously. After 4 months, the pigs were sacrificed, then 3 arthroscopic surgeons evaluated the medial femoral condyles via video-recorded simulated arthroscopy using the ICRS scoring system. The surgeons repeated the evaluation twice within a 9-month period using their recorded arthroscopy. Results: The porcine cartilage repair model produced cartilage repair tissue of poor to good quality. The mean ICRS total scores for all observations were 6.6 (SD, 2.6) in arthroscopy, 5.9 (SD, 2.7) in the first reevaluation, and 6.2 (SD, 2.8) in the second reevaluation. The interrater reliability with the intraclass correlation coefficient (ICC) for the ICRS total scores (ICC, 0.46-0.60) and for each individual subscore (ICC, 0.26-0.71) showed poor to moderate reliability. The intrarater reliability with the ICC also showed poor to moderate reliability for ICRS total scores (ICC, 0.52-0.59) and for each individual subscore (ICC, 0.29-0.58). A modified Bland-Altman plot for the initial arthroscopy and for the 2 reevaluations showed an evident disagreement among the observers. Conclusion: In an animal cartilage repair model, the ICRS scoring system seems to have poor to moderate reliability. Clinical Relevance: Arthroscopic assessment of cartilage repair using the ICRS scoring method has limited reliability. We need more objective methods with acceptable reliability to evaluate cartilage repair outcomes.

scholarly journals Learning As It Happens: A Decade of Analyzing and Shaping a Large-Scale Online Learning System

2018 ◽  
Vol 5 (2) ◽  
Author(s):  
Matthieu J. S. Brinkhuis ◽  
Alexander O. Savi ◽  
Abe D. Hofman ◽  
Frederik Coomans ◽  
Han L. J. Van der Maas ◽  
...  
Keyword(s):  
Online Learning ◽  
Large Scale ◽  
Response Times ◽  
Learning System ◽  
Learning Gains ◽  
Online Experimentation ◽  
Quality Of Fit ◽  
Item Reliability ◽  
Made In

With the advent of computers in education, and the ample availability of online learning and practice environments, enormous amounts of data on learning become available. The purpose of this paper is to present a decade of experience with analyzing and improving an online practice environment for math, which has thus far recorded over a billion responses. We present the methods we use to both steer and analyze this system in real-time, using scoring rules on accuracy and response times, a tailored rating system to provide both learners and items with current ability and difficulty ratings, and an adaptive engine that matches learners to items. Moreover, we explore the quality of fit by means of prediction accuracy and parallel item reliability. Limitations and pitfalls are discussed by diagnosing sources of misfit, like violations of unidimensionality and unforeseen dynamics. Finally, directions for development are discussed, including embedded learning analytics and a focus on online experimentation to evaluate both the system itself and the users’ learning gains. Though many challenges remain open, we believe that large steps have been made in providing methods to efficiently manage and research educational big data from a massive online learning system.

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