scholarly journals Impact of Self-Cleansing Criteria Choice on the Optimal Design of Sewer Networks in South America

Water ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1148 ◽  
Author(s):  
Carlos Montes ◽  
Zoran Kapelan ◽  
Juan Saldarriaga
Keyword(s):  
Optimal Design ◽  
Low Income ◽  
Design Flow ◽  
The Self ◽  
Design Criteria ◽  
Flow Rates ◽  
Sewer Systems ◽  
Sewer Network ◽  
Final Design ◽  
Sewer Networks

This paper aims to analyze different sediment self-cleansing criteria and to find out what the corresponding implications are on the optimal design of sewer systems. A methodology based on enumeration is used to find the sewer network design that minimizes the costs of construction while fulfilling a number of design criteria including self-cleansing constraints. Three stormwater and wastewater sewer networks are used for the analyses. The results indicate that in cases where the terrain slopes and design flow rates are higher, the self-cleansing restrictions are irrelevant to the optimal design. However, when the terrain slopes and the design flow rates are lower, these restrictions affect the final design. Using the results obtained, a graph is constructed showing the limit at which self-cleansing restrictions become a constraining parameter in optimal design for sewer networks. It is expected that this graph will be useful for the design of future sewer networks in low-income areas, where the design of traditional, gravity-based sewer systems is essential.

GA–GHCA model for the optimal design of pumped sewer networks

2015 ◽  
Vol 42 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Maryam Rohani ◽  
Mohammad Hadi Afshar
Keyword(s):  
Genetic Algorithm ◽  
Optimal Design ◽  
Cellular Automata ◽  
Hybrid Model ◽  
Alternative Methods ◽  
Hybrid Cellular Automata ◽  
Network Characteristics ◽  
Sewer Network ◽  
Considerable Success ◽  
Sewer Networks

In this paper, a hybrid model, GA–GHCA, composed of the genetic algorithm (GA) and the general hybrid cellular automata (GHCA) is proposed for the efficient and effective optimal design of pumped sewer networks with fixed layout. The GHCA model was recently introduced by the authors with considerable success for the optimal design of sewer networks. Two alternative versions of the GA–GHCA model are proposed. In the first approach, the pump locations and the corresponding pumping heads are decided by the GA model, while the diameter and nodal cover depths of the network pipes are optimally determined by the GHCA model considering the predefined pump locations and their pumping heights defined by the GA. In the second model, however, only the pump locations are decided by the GA model and for each GA individual, the network characteristics including the pipe diameters, pipe nodal cover depths, and the pumping heights at the predefined locations are determined by the GHCA model. The proposed GA–GHCA model is tested against a benchmark example of pumped sewer network and the results are presented and compared to those of the existing methods. The results indicate that the proposed method is more efficient and effective than alternative methods for the optimal design of pumped sewer networks.

Выбор методов реконструкции самотечных канализационных сетей

2019 ◽  
pp. 35-41
Author(s):  
Viktor, Vasil’ev ◽  
G. Morozov ◽  
S. Zhukov
Keyword(s):  
System Approach ◽  
Block Diagram ◽  
Essential Element ◽  
The Self ◽  
Operating Costs ◽  
Reconstruction Method ◽  
Existing Structures ◽  
Sewage System ◽  
Automation Control ◽  
Sewer Networks

Реконструкция канализационных сетей становится важнейшим элементом поддержания всей системы канализации в рабочем состоянии за счет минимизации эксплуатационных затрат, увеличения срока службы трубопроводов, повышения автономности в работе системы с помощью современных средств автоматизации, контроля и анализа. Для того чтобы максимально продлить срок службы трубопроводов и не причинить вреда параллельно проложенным инженерным сетям, необходимо грамотно подбирать методы и способы реконструкции сетей, основываясь на опыте и анализе работы существующих. Рассмотрены и классифицированы основные методы реконструкции и ремонта трубопроводов. Отмечена необходимость в системной реконструкции. Разработана блок-схема, позволяющая выбрать метод реконструкции в зависимости от характера разрушения трубопровода на основании телеметрического обследования. Приведены примеры ее применения на реальных объектах. Статья написана на основе анализа технической литературы и опыта эксплуатации и проектирования канализационных сетей в Санкт-Петербурге.Rehabilitation of sewer networks becomes an essential element in maintaining the entire sewage system in running order by minimizing the operating costs, increasing the life of pipelines, increasing the self-sustainability of the system using advanced automation, control and analysis tools. In order to maximize the life of pipelines and eliminate damaging parallel laid utility networks, it is necessary to correctly choose the methods of networks rehabilitation based on the experience and analysis of the existing ones. The main methods of repair and rehabilitation of pipelines are considered and classified. The necessity for system approach to the reconstruction is noted. A block diagram has been developed that provides for choosing a reconstruction method depending on the nature of the pipeline destruction and based on the telemetry inspection. Examples of its application in the existing structures are given. The article is written on the basis of an analysis of the technical publications and experience of operating and designing sewer networks in St. Petersburg.

scholarly journals Laser-Doppler Velocimetry Measurements Inside a Backward Curved Centrifugal Fan

2001 ◽  
Vol 7 (3) ◽  
pp. 173-181
Author(s):  
Tong-Miin Liou ◽  
Meng-Yu Chen
Keyword(s):  
Flow Rate ◽  
Turbulence Intensity ◽  
Laser Doppler Velocimetry ◽  
Reverse Flow ◽  
Flow Region ◽  
Design Flow ◽  
Laser Doppler ◽  
Centrifugal Fan ◽  
Doppler Velocimetry ◽  
Flow Rates

Laser-Doppler velocimetry (LDV) measurements are presented of relative mean velocity and turbulence intensity components inside the impeller passage of a centrifugal fan with twelve backward curved blades at design, under-design, and over-design flow rates. Additional LDV measurements were also performed at the volute outlet to examine the uniformity of the outlet flow for the three selected flow rates. Complementary flow visualization results in the tongue region are further presented. It is found that the number of characteristic flow regions and the average turbulence level increase with decreasing air flow rate. For the case of under-design flow rate, there are a through-flow region on the suction side, a reverse flow region on the pressure side, and a shear layer region in between. The corresponding average turbulence intensity is as high as 9.1% of blade tip velocity.

Self-employed surfers, universal credit and the minimally decent life

Legal Studies ◽  
2021 ◽  
pp. 1-18
Author(s):  
Christopher Rowe
Keyword(s):  
Social Security ◽  
Low Income ◽  
Judicial Review ◽  
The Self ◽  
Tax Credits ◽  
Minimum Income ◽  
Wage Labour ◽  
The Social ◽  
Decent Life ◽  
The Government

Abstract As part of its response to Covid-19 the government paused the use of the ‘Minimum Income Floor’ (MIF), which restricts the Universal Credit (UC) entitlement of the self-employed. This paper places the MIF in the wider context of conditionality in the social security system and considers a judicial review which claimed that the MIF was discriminatory. The paper focuses on how UC affects the availability of real choices for low-income citizens to limit or escape from wage labour, with two implications of the move to UC highlighted. First, the overlooked labour decommodifying aspect of tax credits, which provided a minimum income guarantee and a genuine alternative to wage labour for people who self-designated as ‘self-employed’, even if their earnings were minimal or non-existent, has been removed. Secondly, UC has in some respects improved the position of low-paid wage labourers in ‘mini-jobs’, who are not subject to conditionality once they work for the equivalent of approximately nine hours a week on the minimum wage.

scholarly journals Health Inequalities in the Diverse World of Self-Employment: A Swedish National Cohort Study

2021 ◽  
Vol 18 (23) ◽  
pp. 12301
Author(s):  
Karl Gauffin ◽  
Andrea Dunlavy
Keyword(s):  
Health Outcomes ◽  
Health Inequalities ◽  
Low Income ◽  
Employment Status ◽  
The Self ◽  
Poor Health ◽  
Self Employment ◽  
Regular Employment ◽  
National Cohort ◽  
The Relationship

With labor being a central social determinant of health, there is an increasing need to investigate health inequalities within the heterogenous and growing population in self-employment. This study aimed to longitudinally investigate the relationship between income level, self-employment status and multiple work-related health indicators in a Swedish national cohort (n = 3,530,309). The study investigated the relationship between self-employment status and health outcomes later in life. All poor health outcomes, with the exception of alcohol-related disorders, were more common in the self-employed population, compared to the group in regular employment. The income gradient, however, was more pronounced in the group with regular employment than the groups in self-employment. The study found clear connections between low income and poor health in all employment groups, but the gradient was more pronounced in the group in regular employment. This suggests that income has a weaker connection to other types of health promoting resources in the self-employed population. Potentially, lacking social and public support could make it difficult for unhealthy individuals to maintain low-income self-employment over a longer time period.

Using a Resistance Lens to Understand Performative Compliance of Low-Income Lone Mothers

Affilia ◽  
2021 ◽  
pp. 088610992110560
Author(s):  
Silvia L. Vilches ◽  
Jane Pulkingham
Keyword(s):  
Conceptual Framework ◽  
Low Income ◽  
Support Staff ◽  
The Self ◽  
Income Support ◽  
Welfare To Work ◽  
Eligibility Criteria ◽  
Lone Mothers ◽  
State And Market ◽  
Income Assistance

The agency of lone mothers who rely on government income supports is often erased by the discourse of dependency, especially under welfare-to-work eligibility criteria. Here we apply the concept of small acts of micro-resistance in constrained circumstances, augmented by conceptualization of resistance as conscious oppositionality and intentionality to understand the agency of lone-mothers who receive income-assistance (IA) as they make-do and raise children under state- and market-enforced rules. Using a resistance lens reveals the interconnected importance of everyday acts like “talking back” to income-support staff, surreptitious gleaning of goods for resale, and re-storying the self. We describe these in three modalities: resistance as evasion and subterfuge; resistance through asserting positive identities; and resistance in forging their own path. Using a conceptual framework of resistance reveals the extent to which women’s survival and capacity to raise children are contingent on a performance of compliance, demonstrating the impacts of welfare-to-work on female-headed lone parent families.

Sign in / Sign up

Export Citation Format

Share Document