scholarly journals A New Look at Geyser Formation in Sewer Systems

2021 ◽  
Author(s):  
Steven J. Wright ◽  
Keyword(s):  
Laboratory Experiments ◽  
Alternative Explanation ◽  
Scale Effects ◽  
Previous Analysis ◽  
Experimental System ◽  
Small Scale ◽  
Sewer Systems ◽  
Starting Point ◽  
Potential Scale ◽  
A Site

Previous analysis of pressure and velocity data collected at a site experiencing stormwater geysers suggested a mechanism for the occurrence. Laboratory experiments attempting to reproduce the geysers were promising but inconclusive due to potential scale effects in the small scale experiments. Subsequent researchers have generally used this early work as the starting point for subsequent laboratory experiments. Over the years, a number of videos of geysers in actual systems have been obtained and a review of important features from these videos calls into question certain aspects of the original hypothesis. An alternative explanation for the phenomenon has been developed and an experimental system has been identified that may help resolve some questions. However, laboratory experiments may also be impacted by scale effects and several preliminary studies must be conducted to determine whether there is a fruitful path forward in advancing our knowledge of this phenomenon.

Evaluating the hydraulic conductivity at three different scales within an unconfined sand aquifer at Lachenaie, Quebec

2005 ◽  
Vol 42 (4) ◽  
pp. 1212-1220 ◽  
Author(s):  
Robert P Chapuis ◽  
Véronique Dallaire ◽  
Denis Marcotte ◽  
Michel Chouteau ◽  
Nelson Acevedo ◽  
...  
Keyword(s):  
Hydraulic Conductivity ◽  
Scale Effect ◽  
Large Scale ◽  
Scale Effects ◽  
Pumping Test ◽  
Field Variable ◽  
Small Scale ◽  
Sand Aquifer ◽  
Variable Head ◽  
A Site

This paper presents the evaluation of scale effects for the hydraulic conductivity, k, of a sand. Data were obtained using several methods at a site that was densely instrumented with piezometers within an area of about 100 m × 100 m. The 3.1–3.6 m thick sand deposit rests on a thick, nonfissured Champlain Sea clay deposit. At the small scale, local k values were obtained from the grain-size curves of sand samples and also from ground-penetrating radar surveys. At the intermediate scale, k values were obtained from field variable-head tests using piezometers. At the large scale, k values were obtained from pumping-test drawdowns in steady-state conditions. In this sand aquifer, the careful evaluations at three scales gave similar narrow distributions for the hydraulic conductivity, and therefore no scale effect is evidenced.Key words: hydraulic conductivity, sand, scale effect, gradation, monitoring well, pumping.

Indirect Assessment of Attitudes with Response-Time-Based Measures

2006 ◽  
Vol 37 (3) ◽  
pp. 131-139 ◽  
Author(s):  
Juliane Degner ◽  
Dirk Wentura ◽  
Klaus Rothermund
Keyword(s):  
Social Cognitive ◽  
Incremental Validity ◽  
Self Report ◽  
Small Scale ◽  
Implicit Measures ◽  
Scale Theory ◽  
Starting Point ◽  
Self Reports ◽  
Predicting Behavior ◽  
Social Cognitive Theories

Abstract: We review research on response-latency based (“implicit”) measures of attitudes by examining what hopes and intentions researchers have associated with their usage. We identified the hopes of (1) gaining better measures of interindividual differences in attitudes as compared to self-report measures (quality hope); (2) better predicting behavior, or predicting other behaviors, as compared to self-reports (incremental validity hope); (3) linking social-cognitive theories more adequately to empirical research (theory-link hope). We argue that the third hope should be the starting point for using these measures. Any attempt to improve these measures should include the search for a small-scale theory that adequately explains the basic effects found with such a measure. To date, small-scale theories for different measures are not equally well developed.

Design and Operation of Small Wastewater Treatment Plants by the Microbial Film Process

1990 ◽  
Vol 22 (3-4) ◽  
pp. 139-144 ◽  
Author(s):  
S. Iwai ◽  
Y. Oshino ◽  
T. Tsukada
Keyword(s):  
Urban Areas ◽  
Wastewater Treatment Plants ◽  
Waste Water Treatment ◽  
Small Scale ◽  
Small Communities ◽  
Fishing Villages ◽  
Sewer Systems ◽  
Water Treatment Plants ◽  
History Of ◽  
Microbial Film

Although the ratio of sewer systems to population in Japan has been improving in recent years, the construction of sewer systems in small communities such as farming or fishing villages, etc. had lagged behind that of urban areas. However, construction of small-scale sewer systems in farming and fishing villages has been actively carried out in recent years. This report explains the history of the promotion of small-scale sewer systems, why submerged filter beds are being employed in many cases, and introduces the design, operation and maintenance of representative waste-water treatment plants in farming and fishing villages which incorporate de-nitrogen and dephosphorization.

scholarly journals A New Approach to Quantifying Bioaccumulation of Elements in Biological Processes

Biology ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 345
Author(s):  
Kinga Proc ◽  
Piotr Bulak ◽  
Monika Kaczor ◽  
Andrzej Bieganowski
Keyword(s):  
Element Concentration ◽  
Experimental System ◽  
Small Scale ◽  
New Approach ◽  
Realistic Situation ◽  
Initial Load ◽  
Test Elements ◽  
Organism Growth ◽  
Bioaccumulation Index ◽  
Phosphorous Concentration

Bioaccumulation, expressed as the bioaccumulation factor (BAF), is a phenomenon widely investigated in the natural environment and at laboratory scale. However, the BAF is more suitable for ecological studies, while in small-scale experiments it has limitations, which are discussed in this article. We propose a new indicator, the bioaccumulation index (BAI). The BAI takes into account the initial load of test elements, which are added to the experimental system together with the biomass of the organism. This offers the opportunity to explore the phenomena related to the bioaccumulation and, contrary to the BAF, can also reveal the dilution of element concentration in the organism. The BAF can overestimate bioaccumulation, and in an extremal situation, when the dilution of element concentration during organism growth occurs, the BAF may produce completely opposite results to the BAI. In one of the examples presented in this work (Tschirner and Simon, 2015), the concentration of phosphorous in fly larvae was lower after the experiment than in the younger larvae before the experiment. Because the phosphorous concentration in the feed was low, the BAF indicated a high bioaccumulation of this element (BAF = 14.85). In contrast, the BAI showed element dilution, which is a more realistic situation (BAI = −0.32). By taking more data into account, the BAI seems to be more valid in determining bioaccumulation, especially in the context of entomoremediation research.

scholarly journals Double mode model of size-dependent chaotic vibrations of nanoplates based on the nonlocal elasticity theory

2021 ◽  
Author(s):  
Jan Awrejcewicz ◽  
Grzegorz Kudra ◽  
Olga Mazur
Keyword(s):  
Elasticity Theory ◽  
Nonlocal Elasticity ◽  
Scale Effects ◽  
Plate Theory ◽  
Nonlocal Parameter ◽  
Nonlocal Elasticity Theory ◽  
Phase Portraits ◽  
Small Scale ◽  
Governing System ◽  
Account Due

AbstractIn this paper vibrations of the isotropic micro/nanoplates subjected to transverse and in-plane excitation are investigated. The governing equations of the problem are based on the von Kármán plate theory and Kirchhoff–Love hypothesis. The small-size effect is taken into account due to the nonlocal elasticity theory. The formulation of the problem is mixed and employs the Airy stress function. The two-mode approximation of the deflection and application of the Bubnov–Galerkin method reduces the governing system of equations to the system of ordinary differential equations. Varying the load parameters and the nonlocal parameter, the bifurcation analysis is performed. The bifurcations diagrams, the maximum Lyapunov exponents, phase portraits as well as Poincare maps are constructed based on the numerical simulations. It is shown that for some excitation conditions the chaotic motion may occur in the system. Also, the small-scale effects on the character of vibrating regimes are illustrated and discussed.

scholarly journals Nonlinear magneto-thermo-elastic vibration of mass sensor armchair carbon nanotube resting on an elastic substrate

2020 ◽  
Vol 7 (1) ◽  
pp. 153-165
Author(s):  
Rajendran Selvamani ◽  
M. Mahaveer Sree Jayan ◽  
Rossana Dimitri ◽  
Francesco Tornabene ◽  
Farzad Ebrahimi
Keyword(s):  
Carbon Nanotube ◽  
Mechanical Response ◽  
Scale Effects ◽  
Nonlocal Elasticity Theory ◽  
Wave Dispersion ◽  
Elastic Vibration ◽  
Ultrasonic Waves ◽  
Small Scale ◽  
Dimensionless Frequency ◽  
Mass Sensors

AbstractThe present paper aims at studying the nonlinear ultrasonic waves in a magneto-thermo-elastic armchair single-walled (SW) carbon nanotube (CNT) with mass sensors resting on a polymer substrate. The analytical formulation accounts for small scale effects based on the Eringen’s nonlocal elasticity theory. The mathematical model and its differential equations are solved theoretically in terms of dimensionless frequencies while assuming a nonlinear Winkler-Pasternak-type foundation. The solution is obtained by means of ultrasonic wave dispersion relations. A parametric work is carried out to check for the effect of the nonlocal scaling parameter, together with the magneto-mechanical loadings, the foundation parameters, the attached mass, boundary conditions and geometries, on the dimensionless frequency of nanotubes. The sensitivity of the mechanical response of nanotubes investigated herein, could be of great interest for design purposes in nano-engineering systems and devices.

scholarly journals Tephra4D: A Python-Based Model for High-Resolution Tephra Transport and Deposition Simulations—Applications at Sakurajima Volcano, Japan

Atmosphere ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 331
Author(s):  
Kosei Takishita ◽  
Alexandros P. Poulidis ◽  
Masato Iguchi
Keyword(s):  
Scale Effects ◽  
Three Dimensional ◽  
Particle Diameter ◽  
Terminal Velocity ◽  
Diameter Distribution ◽  
Velocity Variation ◽  
Small Scale ◽  
Modified Model ◽  
Sakurajima Volcano ◽  
Ash Transport

Vulcanian eruptions (short-lived explosions consisting of a rising thermal) occur daily in volcanoes around the world. Such small-scale eruptions represent a challenge in numerical modeling due to local-scale effects, such as the volcano’s topography impact on atmospheric circulation and near-vent plume dynamics, that need to be accounted for. In an effort to improve the applicability of Tephra2, a commonly-used advection-diffusion model, in the case of vulcanian eruptions, a number of key modifications were carried out: (i) the ability to solve the equations over bending plume, (ii) temporally-evolving three-dimensional meteorological fields, (iii) the replacement of the particle diameter distribution with observed particle terminal velocity distribution which provides a simple way to account for the settling velocity variation due to particle shape and density. We verified the advantage of our modified model (Tephra4D) in the tephra dispersion from vulcanian eruptions by comparing the calculations and disdrometer observations of tephra sedimentation from four eruptions at Sakurajima volcano, Japan. The simulations of the eruptions show that Tephra4D is useful for eruptions in which small-scale movement contributes significantly to ash transport mainly due to the consideration for orographic winds in advection.

scholarly journals Parametric vibrations of graphene sheets based on the double mode model and the nonlocal elasticity theory

2021 ◽  
Author(s):  
Jan Awrejcewicz ◽  
Grzegorz Kudra ◽  
Olga Mazur
Keyword(s):  
Elasticity Theory ◽  
Nonlocal Elasticity ◽  
Nonlinear Oscillations ◽  
Scale Effects ◽  
Equations Of Motion ◽  
Nonlocal Elasticity Theory ◽  
Small Scale ◽  
Largest Lyapunov Exponent ◽  
Graphene Sheets ◽  
Parametric Vibrations

AbstractParametric vibrations of the single-layered graphene sheet (SLGS) are studied in the presented work. The equations of motion govern geometrically nonlinear oscillations. The appearance of small effects is analysed due to the application of the nonlocal elasticity theory. The approach is developed for rectangular simply supported small-scale plate and it employs the Bubnov–Galerkin method with a double mode model, which reduces the problem to investigation of the system of the second-order ordinary differential equations (ODEs). The dynamic behaviour of the micro/nanoplate with varying excitation parameter is analysed to determine the chaotic regimes. As well the influence of small-scale effects to change the nature of vibrations is studied. The bifurcation diagrams, phase plots, Poincaré sections and the largest Lyapunov exponent are constructed and analysed. It is established that the use of nonlocal equations in the dynamic analysis of graphene sheets leads to a significant alteration in the character of oscillations, including the appearance of chaotic attractors.

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