scholarly journals The Influence of Design Parameters on Straight Bevel Gear Dynamics

2015 ◽  
Vol 5 (2) ◽  
pp. 114
Author(s):  
Chiu-Fan Hsieh ◽  
You-Qing Zhu
Keyword(s):  
Statistical Analysis ◽  
The Other ◽  
Design Parameters ◽  
Bevel Gears ◽  
Straight Bevel Gear ◽  
Pressure Angle ◽  
Stress Fluctuation ◽  
Shaft Angle ◽  
Statistical Results ◽  
Component Force

<p class="1Body">This study analyzes the influence of design parameters on the dynamics of straight bevel gears by constructing a model that allows variation in the shaft angle, pressure angle, and backlash. According to the statistical analysis, the order of influence of these parameters on weight is shaft angle &gt; pressure angle &gt; backlash. When the shaft angle is 90°, the statistical results show the drive is stable and the stress fluctuation level is low. The pressure angle, on the other hand, can affect the gear’s dynamic property by influencing the driving component force on the gear and the component force on the shaft. The results for the shaft and pressure angles are used to determine the appropriate backlash. Overall, the analysis not only provides designers with an important reference but explains the dominance in the market of gear designs with a 90° shaft angle and a 20° pressure angle.</p>

Designers’ Willingness Assessment to Use Recycled and Salvaged Materials in Landscape Architecture

2014 ◽  
Vol 935 ◽  
pp. 138-141
Author(s):  
Zahra Balador ◽  
Zahra Raeisi
Keyword(s):  
Statistical Analysis ◽  
Greenhouse Gas Emissions ◽  
Greenhouse Gas ◽  
Landscape Architecture ◽  
The Other ◽  
Construction Sites ◽  
Material Management ◽  
Gas Emissions ◽  
Management Guidelines ◽  
Statistical Results

Using salvages and reused materials is an effort to conserve energy and other resources, and reduce greenhouse gas emissions; on the other hand, these materials cost a fraction of the price of new. The information generated by this study revealed several useful material management guidelines. Statistical results shows that designers who are educated about these products and how they can be used, are interested in using recycled materials, and can potentially decrease the amount of trash being produced on a much larger level. All information was obtained from product brochures, manufacturer websites, visiting construction sites, statistical analysis and conversations with designers.

scholarly journals Proposal of an Adaptive Neurofuzzy System to Control Flow Power in Distributed Generation Systems

Complexity ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Helbert Eduardo Espitia ◽  
Iván Machón-González ◽  
Hilario López-García ◽  
Guzmán Díaz
Keyword(s):  
Statistical Analysis ◽  
Distributed Generation ◽  
Distribution System ◽  
Voltage Control ◽  
Control Flow ◽  
The Other ◽  
Charge Variation ◽  
Flow Power ◽  
Dynamics Identification ◽  
Neurofuzzy Systems

Systems of distributed generation have shown to be a remarkable alternative to a rational use of energy. Nevertheless, the proper functioning of them still manifests a range of challenges, including both the adequate energy dispatch depending on the variability of consumption and the interaction between generators. This paper describes the implementation of an adaptive neurofuzzy system for voltage control, regarding the changes observed in the consumption within the distribution system. The proposed design employs two neurofuzzy systems, one for the plant dynamics identification and the other for control purposes. This focus optimizes the controller using the model achieved through the identification of the plant, whose changes are produced by charge variation; consequently, this process is adaptively performed. The results show the performance of the adaptive neurofuzzy system via statistical analysis.

Was This in Your Statistics Textbook? IV. Frequency Data

1989 ◽  
Vol 25 (1) ◽  
pp. 11-25
Author(s):  
D. J. Finney
Keyword(s):  
Statistical Analysis ◽  
Contingency Tables ◽  
The Other ◽  
Frequency Data ◽  
Significance Tests ◽  
Test Statistic ◽  
Jumping To Conclusions ◽  
Proper Role ◽  
Measure Of Association

SUMMARYObservations that are frequencies rather than measurements often call for special types of statistical analysis. This paper comments on circumstances in which methods for one type of data can sensibly be used for the other. A section on two-way contingency tables emphasizes the proper role of χ2 a test statistic but not a measure of association; it mentions the distinction between one-tail and two-tail significance tests and reminds the reader of dangers. Multiway tables bring new complications, and the problems of interactions when additional classificatory factors are explicit or hidden are discussed at some length. A brief outline attempts to show how probit, logit, and similar techniques are related to the analysis of contingency tables. Finally, three unusual examples are described as illustrations of the care that is needed to avoid jumping to conclusions on how frequency data should be analysed.

Synthesis of the internal parallel cam mechanism

1998 ◽  
Vol 212 (7) ◽  
pp. 577-585 ◽  
Author(s):  
M Nishioka ◽  
T Nishimura
Keyword(s):  
Parametric Analysis ◽  
Parallel Mechanism ◽  
Design Parameters ◽  
Cam Mechanism ◽  
Pressure Angle

Parallel cam mechanisms have been studied in different ways. In this paper, a parametric formulation which can cover every configuration of the parallel cam mechanism is derived. As a result of parametric analysis, a new, last mechanism was found. This cam is essentially an internal cam mechanism. Based on the assumption of an equally distributed roller follower, the basic configurations of the mechanism are derived from both the pressure angle and the undercutting constraints. As a result, the possible number of rollers per spider plate is two. Thus the feasible area of the design parameters of the mechanisms are obtained. The advantages of the mechanism over the conventional parallel mechanism are the saving of space and a larger angular stroke of output.

Changes in Nutrient Levels of Lake Water Stored at 4 °C

1984 ◽  
Vol 41 (6) ◽  
pp. 985-988 ◽  
Author(s):  
A. H. El-Shaarawi ◽  
M. A. Neilson
Keyword(s):  
Statistical Analysis ◽  
Lake Water ◽  
Water Samples ◽  
Soluble Reactive Phosphorus ◽  
Lake Ontario ◽  
The Other ◽  
Nutrient Levels ◽  
Glass Bottles ◽  
Reactive Phosphorus

Water samples were collected on Lake Ontario during April and November, filtered (0.45 μm), and immediately analyzed onboard ship for the nutrients soluble reactive phosphorus, nitrate-plus-nitrite, and ammonia. Replicates were stored in glass bottles at 4 °C and reanalyzed within 8 d. Statistical analysis showed that soluble reactive phosphorus decreased by 11 and 13% and nitrate-plus-nitrite by 7 and 6%, whereas ammonia increased by 75% on one cruise and decreased by 37% on the other.

Deformations and Stresses in Face-Hobbed Spiral Bevel Gears

2011 ◽  
Author(s):  
Vilmos V. Simon
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Nodal Point ◽  
Design Parameters ◽  
Element Discretization ◽  
Spiral Bevel Gears ◽  
Bevel Gears ◽  
Tooth Surfaces ◽  
Spiral Bevel ◽  
Element Method

In this study an attempt is made to predict displacements and stresses in face-hobbed spiral bevel gears by using the finite element method. A displacement type finite element method is applied with curved, 20-node isoparametric elements. A method is developed for the automatic finite element discretization of the pinion and the gear. The full theory of the generation of tooth surfaces of face-hobbed spiral bevel gears is applied to determine the nodal point coordinates on tooth surfaces. The boundary conditions for the pinion and the gear are set automatically as well. A computer program was developed to implement the formulation provided above. By using this program the influence of design parameters and load position on tooth deflections and fillet stresses is investigated. On the basis of the results, obtained by performing a big number of computer runs, by using regression analysis and interpolation functions, equations for the calculation of tooth deflections and fillet stresses are derived.

scholarly journals Hypermobility and sports injury

2018 ◽  
Vol 4 (1) ◽  
pp. e000366 ◽  
Author(s):  
Joseph Alexander Nathan ◽  
Kevin Davies ◽  
Ian Swaine
Keyword(s):  
Statistical Analysis ◽  
Sports Injury ◽  
The Other ◽  
Anecdotal Evidence ◽  
Demographic Information ◽  
Cross Sectional Survey ◽  
Cross Sectional ◽  
Exact Test ◽  
Joint Dislocation ◽  
Ligament Sprain

ObjectiveTo determine whether there is an association between hypermobility and sports injury.MethodsA quantitative observational approach using a cross-sectional survey was adopted. Individuals were identified as hypermobile or not. All participants were asked to complete two questionnaires: one asking demographic information and the other injury-specific. Fisher’s exact test was used for statistical analysis.Results114 individuals participated in the study, 62 women and 52 men. 26% of the participants were hypermobile. There was no significant association between hypermobility and sports injury (p=0.66). There was a significant increase in joint and ligament sprain among the non-hypermobile (NH) group covering all sports (p=0.03). Joint dislocation was found exclusively among hypermobile individuals. The duration of injury in hypermobile individuals was higher than NH. The use of oral painkillers or anti-inflammatories in the semiprofessional group was greater than the general population.ConclusionHypermobility is relatively common among individuals, and there is a lot of anecdotal evidence associating it with increased rates of injuries. This project finds that NH individuals are more likely to sustain a ligament or joint sprain in sports. This is due to increased joint laxity and flexibility preventing injury. There were important limitations to this study which will be addressed in further work. These include assessing for pauciarticular hypermobility and focusing on one sport to investigate its association with sports injury in those who are hypermobile or not. It would also be important to focus on one specific joint, assessing its flexibility and association with injury.

Statistics and Economic History

1941 ◽  
Vol 1 (1) ◽  
pp. 26-41 ◽  
Author(s):  
Simon Kuznets
Keyword(s):  
Statistical Analysis ◽  
Economic History ◽  
Raw Materials ◽  
The Other ◽  
Economic Study ◽  
Statistical Research ◽  
Historical Approach ◽  
The Past ◽  
Economic Inquiry ◽  
Analytical Tools

This paper deals with the relation between statistical analysis as applied in economic inquiry and history as written or interpreted by economic historians. Although both these branches of economic study derive from the same body of raw materials of inquiry—the recordable past and present of economic society—each has developed in comparative isolation from the other. Statistical economists have failed to utilize adequately the contributions that economic historians have made to our knowledge of the past; and historians have rarely employed either the analytical tools or the basic theoretical hypotheses of statistical research. It is the thesis of this essay that such failure to effect a close interrelation between historical approach and statistical analysis needs to be corrected in the light of the final goal of economic study.

Pre-Ozonation-Coagulant Interactions in Direct Filtration

2010 ◽  
Vol 45 (3) ◽  
pp. 317-326 ◽  
Author(s):  
Murat Eyvaz ◽  
Hatice Deniz ◽  
Tuğrul S. Aktaş ◽  
Ebubekir Yüksel ◽  
Ahmet M. Saatçi
Keyword(s):  
Ferric Chloride ◽  
Aluminum Sulfate ◽  
Pilot Scale ◽  
The Other ◽  
Design Parameters ◽  
Dimensionless Number ◽  
Raw Water ◽  
Direct Filtration ◽  
Effluent Quality ◽  
Sulfate Application

Abstract Pre-ozonation–coagulant interactions effects in relation to the coagulant type and dosage in direct filtration of surface waters were investigated. The performance of the process was evaluated by monitoring the effluent quality and head loss development through the filter bed. Two identical pilot scale filter columns filtering the same raw water were operated in parallel. The raw water was brought from Ömerli Reservoir in Istanbul. Before filtering, the raw water flow was split into two equal flows. One of the streams was pre-ozonated and the other was aerated using contact chambers with equal volumes equipped with same number and type of diffusers. In coagulation experiments, one of the filters was operated using aluminum sulfate as a coagulant while the other one was run with ferric chloride. For similar filter run times, the effluent quality was always better with pre-ozonation compared to aeration. It was also observed that, aluminum sulfate application gave more favorable results for both particle and turbidity removal compared to ferric chloride. Ives’ filterability index which incorporates the important filtration design parameters such as: effluent quality, the headloss and the velocity of filtration into a dimensionless number was used for the comparison of the experimental results.

scholarly journals Aferição do pH de diferentes agentes clareadores indicados para o clareamento intracoronário

2018 ◽  
Author(s):  
João Felipe Besegato ◽  
Gabriela Dos Santos Ribeiro Rocha ◽  
Marlene De Sousa Amorim ◽  
Fabio Martins Salomão ◽  
Daniel Poletto ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Statistical Analysis ◽  
Multiple Comparisons ◽  
The Other ◽  
Sodium Perborate ◽  
Distilled Water ◽  
Friedman Test ◽  
Time Intervals ◽  
Ph Values ◽  
Evaluation Time

Objective: to measure pH values of bleaching agents that are indicated to intracoronal bleaching technique in different time intervals. Methods: Each group (G) received five samples (n=5): G1 – distilled water (AD); G2 – hydrogen peroxide (H2O2) 30%; G3 – sodium perborate (PbS) + AD; G4 – PbS + H2O2 30%; G5 – sodium percarbonate (PcS) + AD; and G6 – PcS + H2O2 30%. pH values were stated using a digital pHmeter, in different time intervals: immediately after handling (T0), 24 hours (T1) and 168 hours after handling (T2). The results were submitted to statistical analysis through Kruskal-Wallis and Mann Whitney tests, in this order, allowing multiple comparisons among the groups. To verify the effect of time in each group, Friedman test was applied. Results: In the evaluation of the effect of time in each group, it was observed that G2 presented acid behavior, while the other groups exhibited values close to neutrality or alkaline. Conclusions: H2O2 30% was the only agent that showed acidic behavior in every evaluation time. Meanwhile, PcS + H2O had the highest pH values.

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