Simple Approximate Solutions for Dynamic Response of Suspension System

2022 ◽  
Vol 21 ◽  
pp. 20-31
Author(s):  
Jacob Nagler
Keyword(s):  
Analytic Solution ◽  
Approximate Solutions ◽  
Quantitative Agreement ◽  
Gravitational Energy ◽  
Suspension System ◽  
Approximate Analytic Solution ◽  
Stiffness Properties ◽  
Coupling Case ◽  
The One ◽  
The Impact

An approximate simplified analytic solution is proposed for the one DOF (degree of freedom) static and dynamic displacements alongside the stiffness (dynamic and static) and damping coefficients (minimum and maximum/critical values) of a parallel spring-damper suspension system connected to a solid mass-body gaining its energy by falling from height h. The analytic solution for the prescribed system is based on energy conservation equilibrium, considering the impact by a special G parameter. The formulation is based on the works performed by Timoshenko (1928), Mindlin (1945), and the U. S. army-engineering handbook (1975, 1982). A comparison between the prescribed studies formulations and current development has led to qualitative agreement. Moreover, quantitative agreement was found between the current prescribed suspension properties approximate value - results and the traditionally time dependent (transient, frequency) parameter properties. Also, coupling models that concerns the linkage between different work and energy terms, e.g., the damping energy, friction work, spring potential energy and gravitational energy model was performed. Moreover, approximate analytic solution was proposed for both cases (friction and coupling case), whereas the uncoupling and the coupling cases were found to agree qualitatively with the literature studies. Both coupling and uncoupling solutions were found to complete each other, explaining different literature attitudes and assumptions. In addition, some design points were clarified about the wire mounting isolators stiffness properties dependent on their physical behavior (compression, shear tension), based on Cavoflex catalog. Finally, the current study aims to continue and contribute the suspension, package cushioning and containers studies by using an initial simple pre – design analytic evaluation of falling mass- body (like cushion, containers, etc.).

scholarly journals Modeling of the COVID-19 pandemic in the limit of no acquired immunity

2021 ◽  
Vol 8 (2) ◽  
pp. 282-303
Author(s):  
J. M. Ilnytskyi ◽  
Keyword(s):  
Analytic Solution ◽  
Effective Vaccine ◽  
Acquired Immunity ◽  
Approximate Analytic Solution ◽  
Contact Rate ◽  
Reproduction Ratio ◽  
Numeric Solution ◽  
The One ◽  
Disease Free ◽  
Rate Threshold

We propose the SEIRS compartmental epidemiology model aimed at modeling the COVID-19 pandemy dynamics. The limit case of no acquired immunity (neither natural nor via vaccination) is considered mimicking the situation (i) when no effective vaccine being developed or available yet, and (ii) the virus strongly mutates causing massive reinfections. Therefore, the only means of suppressing the virus spread are via quarantine measures and effective identification and isolation of infected individuals. We found both the disease-free and the endemic fixed points and examined their stability. The basic reproduction ratio is obtained and its dependence on the parameters of the model is discussed. We found the presence of the contact rate threshold beyond which the disease-free fixed point cannot be reached. Using the numeric solution, the approximate analytic solution of the model, characterized by rescaled contact rate, is obtained. Several possible "quarantine on"/"quarantine off" scenarios are considered and the one combined with flexible adjustment of the identification and isolation rates is found to be the most effective in bringing the second and consequent waves down. The study can be interpreted as a reference point for the case when the natural or acquired immunity, as well as vaccination, are taken into account. It will be a topic of a separate study.

An Approximate Analytic Solution of the One-Dimensional Foil Bearing Problem

1999 ◽  
Vol 66 (4) ◽  
pp. 1028-1032 ◽  
Author(s):  
A. A. Renshaw
Keyword(s):  
Iterative Solution ◽  
Approximate Solutions ◽  
Approximate Analytic Solution ◽  
One Dimensional ◽  
Solution Algorithms ◽  
Foil Bearing ◽  
Governing Differential Equation ◽  
Exponential Power ◽  
The One ◽  
Entrained Air

Approximate solutions are found to the one-dimensional steady-state foil bearing problem in which a longitudinally translating, flexible tensioned sheet of material rides on a thin film of entrained air as it wraps around a fixed cylinder. The approximate solutions use the first few terms of a scaled, exponential power series and minimize the squared residual in the governing differential equation. The solutions are simple, compare well with more exact solutions, and provide excellent starting points for more sophisticated, iterative solution algorithms.

New approximate solutions of the Blasius equation

2015 ◽  
Vol 25 (7) ◽  
pp. 1590-1599 ◽  
Author(s):  
Lazhar Bougoffa ◽  
Abdul-Majid Wazwaz
Keyword(s):  
Exact Solution ◽  
Design Methodology ◽  
Analytic Solution ◽  
Approximate Solutions ◽  
Second Step ◽  
Approximate Analytic Solution ◽  
Content Type ◽  
Blasius Problem ◽  
Blasius Equation ◽  
The Given

Purpose – The purpose of this paper is to propose a reliable treatment for studying the Blasius equation, which arises in certain boundary layer problems in the fluid dynamics. The authors propose an algorithm of two steps that will introduce an exact solution to the equation, followed by a correction to that solution. An approximate analytic solution, which contains an auxiliary parameter, is obtained. A highly accurate approximate solution of Blasius equation is also provided by adding a third initial condition y ' ' (0) which demonstrates to be quite accurate by comparison with Howarth solutions. Design/methodology/approach – The approach consists of two steps. The first one is an assumption for an exact solution that satisfies the Blasius equation, but does not satisfy the given conditions. The second step depends mainly on using this assumption combined with the given conditions to derive an accurate approximation that improves the accuracy level. Findings – The obtained approximation shows an enhancement over some of the existing techniques. Comparing the calculated approximations confirm the enhancement that the derived approximation presents. Originality/value – In this work, a new approximate analytical solution of the Blasius problem is obtained, which demonstrates to be quite accurate by comparison with Howarth solutions.

Static and Dynamic Studies of Gasoline in View of its Octane Number and its Toxic Effect

2013 ◽  
Vol 12 (7) ◽  
pp. 451-459
Author(s):  
Ashraf Yehia El-Naggar ◽  
Mohamed A. Ebiad
Keyword(s):  
Toxic Effect ◽  
Aromatic Hydrocarbons ◽  
Octane Number ◽  
Liquid Fuel ◽  
Positive Impact ◽  
Hydrocarbon Composition ◽  
Different Temperatures ◽  
Different Seasons ◽  
The One ◽  
The Impact

Gasoline come primarily from petroleum cuts, it is the preferred liquid fuel in our lives. Two gasoline samples of octane numbers 91 and 95 from Saudi Arabia petrol stations were studied. This study was achieved at three different temperatures 20oC, 30oC and 50oC representing the change in temperatures of the different seasons of the year. Both the evaporated gases of light aromatic hydrocarbons (BTEX) of gasoline samples inside the tank were subjected to analyze qualitatively and quantitatively via capillary gas chromatography. The detailed hydrocarbon composition and the octane number of the studied gasoline samples were determined using detailed hydrocarbon analyzer. The idea of research is indicating the impact of light aromatic compounds in gasoline on the toxic effect of human and environment on the one hand, and on octane number of gasoline on the other hand. Although the value of octane number will be reduced but this will have a positive impact on the environment as a way to produce clean fuel.

The Development of Agritourism in the Podkarpackie Voivodeship in the Light of International and National Conditions

2017 ◽  
Vol 13 ◽  
pp. 244-261
Author(s):  
Mariola Tracz ◽  
Małgorzata Bajgier-Kowalska ◽  
Radosław Uliszak
Keyword(s):  
Development Strategy ◽  
Current State ◽  
Central Statistical ◽  
Central Statistical Office ◽  
Tourism Resources ◽  
The One ◽  
The Impact ◽  
District Offices ◽  
Socio Economic Factors

Podkarpackie Voivodeship is one of the regions of Poland in which the number of agritourism entities is very high. Therefore tourism plays a significant role in its development strategy. The aim of the paper is to identify the current state of agritourism and the changes that have occurred in the region in the years 2000–2016. Specific objectives are to determine the distribution of agritourism farms and their offer, together with a comprehensive analysis of the environmental and socio-economic factors, as well as the impact of the Slovak-Ukrainian border. The report was developed on the statistical materials from the Polish Central Statistical Office, Podkarpackie Agricultural Advisory Centre in Boguchwała and data collected from municipalities and district offices that is published on their websites, as well as through interviews with 100 owners of agritourism farms in the Podkarpackie Voivodeship. The research has shown, on the one hand, the decline in the number of farms in the region and, on the other hand, the increase in the diversity of the tourist offer of these entities. Distribution of agritourism farms is closely linked to the attractiveness of natural environment and quality of secondary tourism resources. Traditional agritourism has not yet fully used its countryside, as well as cross-border advantages of its location.

Laughter on the Fringes

2019 ◽  
Author(s):  
Anna Peterson
Keyword(s):  
The Other ◽  
Literary Canon ◽  
Autobiographical Writing ◽  
Treasure Trove ◽  
Old Comedy ◽  
Other Hand ◽  
Aggressive Humor ◽  
The One ◽  
The Individual ◽  
The Impact

This book examines the impact that Athenian Old Comedy had on Greek writers of the Imperial era. It is generally acknowledged that Imperial-era Greeks responded to Athenian Old Comedy in one of two ways: either as a treasure trove of Atticisms, or as a genre defined by and repudiated for its aggressive humor. Worthy of further consideration, however, is how both approaches, and particularly the latter one that relegated Old Comedy to the fringes of the literary canon, led authors to engage with the ironic and self-reflexive humor of Aristophanes, Eupolis, and Cratinus. Authors ranging from serious moralizers (Plutarch and Aelius Aristides) to comic writers in their own right (Lucian, Alciphron), to other figures not often associated with Old Comedy (Libanius) adopted aspects of the genre to negotiate power struggles, facilitate literary and sophistic rivalries, and provide a model for autobiographical writing. To varying degrees, these writers wove recognizable features of the genre (e.g., the parabasis, its agonistic language, the stage biographies of the individual poets) into their writings. The image of Old Comedy that emerges from this time is that of a genre in transition. It was, on the one hand, with the exception of Aristophanes’s extant plays, on the verge of being almost completely lost; on the other hand, its reputation and several of its most characteristic elements were being renegotiated and reinvented.

Freedom of Expression versus Privacy and the Right to Reputation

2017 ◽  
Author(s):  
Dirk Voorhoof
Keyword(s):  
Public Interest ◽  
Freedom Of Expression ◽  
Media Freedom ◽  
Investigative Journalism ◽  
The Public ◽  
The Right Of Privacy ◽  
The One ◽  
Grand Chamber ◽  
The Right ◽  
The Impact

The normative perspective of this chapter is how to guarantee respect for the fundamental values of freedom of expression and journalistic reporting on matters of public interest in cases where a (public) person claims protection of his or her right to reputation. First it explains why there is an increasing number and expanding potential of conflicts between the right to freedom of expression and media freedom (Article 10 ECHR), on the one hand, and the right of privacy and the right to protection of reputation (Article 8 ECHR), on the other. In addressing and analysing the European Court’s balancing approach in this domain, the characteristics and the impact of the seminal 2012 Grand Chamber judgment in Axel Springer AG v. Germany (no. 1) are identified and explained. On the basis of the analysis of the Court’s subsequent jurisprudence in defamation cases it evaluates whether this case law preserves the public watchdog-function of media, investigative journalism and NGOs reporting on matters of public interest, but tarnishing the reputation of public figures.

Preaching and Sermons

2017 ◽  
Author(s):  
Robert H. Ellison
Keyword(s):  
Eighteenth Century ◽  
North Atlantic ◽  
Religious Revival ◽  
Early Nineteenth Century ◽  
Denominational Identity ◽  
The North ◽  
The North Atlantic ◽  
The One ◽  
The Impact

Prompted by the convulsions of the late eighteenth century and inspired by the expansion of evangelicalism across the North Atlantic world, Protestant Dissenters from the 1790s eagerly subscribed to a millennial vision of a world transformed through missionary activism and religious revival. Voluntary societies proliferated in the early nineteenth century to spread the gospel and transform society at home and overseas. In doing so, they engaged many thousands of converts who felt the call to share their experience of personal conversion with others. Though social respectability and business methods became a notable feature of Victorian Nonconformity, the religious populism of the earlier period did not disappear and religious revival remained a key component of Dissenting experience. The impact of this revitalization was mixed. On the one hand, growth was not sustained in the long term and, to some extent, involvement in interdenominational activity undermined denominational identity; on the other hand, Nonconformists gained a social and political prominence they had not enjoyed since the middle of the seventeenth century and their efforts laid the basis for the twentieth-century explosion of evangelicalism in Africa, Asia, and South America.

scholarly journals Reproduction and biomarker responses of Eisenia fetida after exposure to imidacloprid in biochar-amended soil

Biochar ◽  
2021 ◽  
Author(s):  
Ngitheni Winnie-Kate Nyoka ◽  
Ozekeke Ogbeide ◽  
Patricks Voua Otomo
Keyword(s):  
Eisenia Fetida ◽  
Field Studies ◽  
Application Rate ◽  
Land Application ◽  
Acetylcholinesterase Inhibition ◽  
Beneficial Effects ◽  
Pesticide Pollution ◽  
The One ◽  
The Impact ◽  
Amended Soil

AbstractTerrestrial and aquatic ecosystems are increasingly threatened by pesticide pollution resulting from extensive use of pesticides, and due to the lack of regulatory measures in the developing world, there is a need for affordable means to lessen environmental effects. This study aimed to investigate the impact of biochar amendment on the toxicity of imidacloprid to life-cycle parameters and biomarker responses of the earthworm Eisenia fetida. E. fetida was exposed to 10% biochar-amended and non-amended OECD artificial soils spiked with 0, 0.75, 1.5, 2.25 and 3 mg imidacloprid/kg for 28 days. An LC50 of 2.7 mg/kg was only computed in the non-amended soil but not in the biochar-amended soil due to insignificant mortality. The EC50 calculated in the non-amended soil (0.92 mg/kg) for reproduction (fertility) was lower than the one computed in the biochar amended (0.98 mg/kg), indicating a decrease in toxicity in the biochar-amended substrate. Significant weight loss was observed at the two highest imidacloprid treatments in the non-amended soil and only at the highest treatment in the biochar-amended substrate, further highlighting the beneficial effects of biochar. Catalase activity decreased significantly at the two highest concentrations of non-amended soil. Yet, in the amended soil, the activity remained high, especially in the highest concentration, where it was significantly higher than the controls. This indicated more severe oxidative stress in the absence of biochar. In all non-amended treatments, there was a significant acetylcholinesterase inhibition, while lower inhibition percentages were observed in the biochar-amended soil. In most endpoints, the addition of biochar alleviated the toxic effects of imidacloprid, which shows that biochar has the potential to be useful in soil remediation. However, there is still a need for field studies to identify the most effective application rate of biochar for land application.

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