Discussion: Optimal design of curved bed trapezoidal canal sections

Contribution by A. Laycock, Adrian Laycock Ltd Investigating the theoretical least-cost cross-sectional profile is a favourite academic exercise that has been explored in numerous papers. However, the practical implications of constructing curved section canals are less well documented but far more relevant. In practice the cost is rarely dependent on the theoretical minimum section, and the choice of geometry will depend on various factors, some of which are listed below. lining, which should not create discontinuity-induced internal stress. (e) Ease of placing other lining material, such as less permeable compacted soil or artificial membranes. ( f ) Whether maintenance equipment will be required to operate on the canal bed. (g) The type of sediment expected to be deposited or required to be transported. Curved bed canals are not efficient at transporting coarse sediment, although deposited material will collect in the centre of the channel making it easier to remove during maintenance. (h) Strength of rigid lining. A curved shell is inherently stronger than a section with planar sides and base. A very common cause of failure in trapezoidal lining is cracking at the base of the side slopes where a geometric discontinuity leads to intense stresses from soil pressure, soil movement or external loads. (i) Placing concrete on a long constant slope in a trapezoidal section can be problematic as tension cracks develop owing to slippage of the wet concrete. This is not a problem in large parabolic sections, in which the slope is gradually reducing with depth below the bank top

Design of canals

The book presents firsthand material from the authors on design of hydraulic canals. The book discusses elements of design based on principles of hydraulic flow through canals. It covers optimization of design based on usage requirements and economic constraints. The book includes explicit design equations and design procedures along with design examples for varied cases. With its comprehensive coverage of the principles of hydraulic canal design, this book will prove useful to students, researchers, and practicing engineers. End-of-chapter pedagogical elements make it ideal for use in graduate courses on hydraulic structures offered by most civil engineering departments across the world

Coupled simulation-optimization model for management of groundwater resource

International audienc

Oral health-related quality of life among elderly patients visiting special clinics in public hospitals in Delhi, India: A cross-sectional study

Background: Oral health is recognized as an integral component of general health, and poor oral health is reflected in general health and quality of life (QoL). India has seen a profound shift in the elderly population and is currently home to 103.9 million elders. General Oral Health Assessment Index (GOHAI) is a self-reported oral health assessment index used in elderly population and has been tested in multiple countries. Objective: The study aimed to assess the oral health-related QoL (OHRQoL) using GOHAI and various factors affecting it, among elderly patients visiting special Sunday geriatric clinics at Delhi public hospitals. Methods: A cross-sectional study was conducted among four purposively selected special geriatric public clinics in Delhi, India, and a convenience sample of 145 elderly patients was obtained. OHRQoL was measured using a prevalidated instrument (GOHAI) along with other variables (sociodemographic factors, self-perceived oral health, utilization of medical/dental services, dental problems in the past 12 months, and prosthetic status/need). Statistical analysis was done using Statistical Package for the Social Sciences software version 21, and descriptive results were obtained. Results: The sample consisted of 66 males (45.5%) and 79 females (55.5%), and around 58% (n = 84) of the participants were illiterate. Around 39% (n = 57) of the elderly had never visited a dentist and 48% (n = 69) were financially dependent (no income) on others. The mean GOHAI score for the population was 26.69 + 4.44 (median = 25, interquartile range = 23–27). GOHAI score was compared for age, oral hygiene practices, dental problems in the past 12 months, self-reported oral health, and prosthetic need, and a statistically significant difference was observed. Conclusions: The current study assessed GOHAI score and highlighted important determinants of OHRQoL in elderly population visiting the special clinics in Delhi. Thus, OHRQoL should be considered as a surrogate measure to clinical oral examination