Explore the vast range of titles available.

The experimental investigation was carried out to study the influence of dowel force of longitudinal flexural reinforcement of concrete beams. Due to intricacy involved in shear transfer mechanism accurate predictions of shear behavior was difficult to evaluate. The influence of shear in uncracked compression zone, aggregate interlocking, stirrups is well understood but contribution of dowel force was not clearly represented despite implied belief that dowel force is an important constituent in shear resistance. The idea of present study is to appraise shear resistance arising from dowel force with varying flexural reinforcement with shear reinforcement provided. A total of eight beams were cast and verified as parametric study. Four beams were provided with preformed diagonal tension cracks and another four beams were conventional beams. The study was carried out by keeping shear span to depth ratio and clear cover constant. Results obtained was studied from moment vs. displacement curve and strain vs. moment curve and compared with existing empirical formulas. It was noticed that aggregate interlocking is insignificant with shear reinforcement provided and beams with preformed diagonal tension cracks had exhibited greater structural behavior when compared to conventional beams.

The shear transfer mechanism was examined to view the contributions of different components of shear transfer such as aggregate interlocking, dowel force and uncracked compression zone. Understanding the role of various shear transfer components with transverse reinforcement provided was complex due to traditional difficulties involved in detail assessment of accompanying kinematics during the failure. In the present paper, the issue was addressed by employing sixteen specimens and grouped under two categories representing conventional beams and beams with preformed cracks and were tested under four - point bending load with a shear span to depth ratio of 1.26 by increasing the characteristic strength of concrete. From the results obtained, empirical formulas proposed were also evaluated and it was concluded that the results were consistent and contribution of shear transfer across uncracked compression zone was maximum in shear resistance with transverse reinforcement provided. Later structural behaviour was also assessed and it was concluded that beams with preformed cracks had exhibited greater stiffness thus nullifying the effect of aggregate interlocking in shear transfer.

Identification of parameters governing sediment transport is important, as its understanding can greatly assist in resolving the issues caused by sediment transport in the riverine system. This paper presents the results of an experimental study for the computation of bed load transport rate and suspended load transport rate along with transient bed profile for a cohesive mixture of clay–silt–gravel in which clay varied from 10 to 50% on weight basis. The transport rate of sediment is found to be higher in the initial period of time, however, it decreases with passage of time. Transport rate of sediment decreases with the increase in clay content, while it increases with excess shear stress. Bed degradation was found to be higher in upstream section than that of downstream section. Clay content affects the bed degradation profile as well as equilibrium time. Equilibrium time is found to be increased with clay content. The main parameters affecting the detachment and transport of sediment from cohesive bed are clay content, excess shear stress, and equilibrium time. Relationships have been developed for the computation of bed load transport rate, suspended load transport rate, and transient bed profile along with the auxiliary relationships for initial transport rate of sediment, equilibrium time and maximum degradation. All the developed relationships were found to be in good agreement with the observed ones.

PurposeIncipient motion plays an instrumental role in understanding various aspects of sediment transport, such as river bed aggradation and degradation, channel design, bank erosion, scour around bridge piers, and water quality issues.Materials and methodsExperiments were conducted to study the incipient motion of gravel particles in three types of bed material, i.e., gravels only, silt-gravel mixture, and clay-silt-gravel mixture. The clay content varied from 10 to 50% in the clay-silt-gravel mixture while silt and gravel were in equal proportion by weight. Samples were taken out from the prepared cohesive bed for the determination of their bulk density, unconfined compressive strength, and water content. The incipient motion was observed visually, which corresponded to the beginning of movement of gravel particles in the mixture. The shear stress corresponding to incipient motion was computed using measured flow depth and slope of water surface. The physical appearance of the top layer of cohesive bed was observed visually at the end of experiment.Results and discussionThe effects of clay content, water content, unconfined compressive strength, and bulk density of the mixture on the critical shear stress were investigated using the data collected in this study on clay-silt-gravel mixture along with the data from previous studies. A relationship is proposed for the computation of critical shear stress of gravel particles in the cohesive mixtures. The physical appearance of the top surface of the bed for clay-silt-gravel mixture has also been investigated with varying percentages of clay content in the mixture.ConclusionsHigh clay percentage significantly increased the critical shear stress. The presence of silt lowers the critical shear stress especially when there is low clay content (up to 20%) in the mixture. The clay content along with the bulk density was found to be the dominant parameters that affect the incipient motion of the gravel particles in the cohesive mixtures. The proposed relationship for critical shear stress was found to be in good agreement with the observed ones.

This paper deals with the incipient motion for gravel particles in cohesionless sediment mixtures having silt and sand. The mixtures comprised of gravel–silt and gravel–sand–silt were used in the present experimental study. The critical shear stress for gravel particles was noted to be lower in the presence of silt particles. A formulation has been developed for the determination of critical shear stress of gravel particles. The governing factor includes the mean size of gravel particles, arithmetic mean of mixture, and the probability of hidden–exposure factor. The regression analysis as well as goodness-of-fit test was conducted for the proposed relationship which was found to be in good agreement with the data of present study as well as for other authors. The proposed formulation for the critical shear stress converges to Brownlie’s ( 1981 ) equation in case of uniform sediment.

The most common type of diversion structure used in boulder streams is a trench weir. It is a simple structure built below the bed level of streams, and the top of it is covered with bottom rack. Bottom rack consists of bars of various shapes like circular, rectangle, T-shaped, etc. It is placed over the trench weir with a desired porosity to control sediment ingestion into trench. In this present study, T-shaped bars are used because sediment ingestion and maintenance in the bottom rack consisting of T-shaped bar shall likely too low as compared to the rounded bars and rectangular bars. As in previous studies, Garcia et al. (Water 10(1035):1–21, 2018a, Water 10(1699):1–21, 2018b) compared the blocking capacity of bottom intakes having circular bars with intakes having T-shaped bars, they claimed that circular bar is inefficient as compared to T-shaped bars. The present study is based on experimental investigation of trench weir consisting of T-shaped bars under free flow condition, and it was found that the coefficient of discharge decreases with an increase in clear spacing of rack, slope of bottom rack, specific energy of approach flow, Froude number and Reynolds number. An equation is also being proposed to calculate coefficient of discharge with a maximum error of ± 20%.

In this study, an attempt has been made to study methane flux and quantification of heavy metals from Municipal Solid Waste (MSW) landfill areas of selected cities in India. During the period of study, the average value of methane flux was estimated from these landfill areas varied from 146–454 mg/m2/h. Methane emission from landfill is of serious environmental global concern as it accounts for approximately 15 percentages of current Greenhouse gas emissions. It has been estimated that methane emission, from landfill areas in the world, in next two decades would be same as that what is emitted from paddy fields presently. Besides, the estimation of methane flux, quantification of some heavy metals was conducted to analyse the suitability of using MSW as compost. The average values for metals were observed to be both within the range of USEPA and Indian standards for MSW disposal in landfill areas and to be used as compost respectively.

The adverse effect of greenhouse emissions like CO2 leads to global warming. As per statistics, the global contribution of the cement manufacturing industry to greenhouse gas emissions is nearly 7%. To address these effects on the nature of the environment associated with cement manufacturing, it is necessary to explore sustainable binders for manufacturing concrete. Hence, extensive research is being conducted in the recent past to replace cement with various materials including waste generated from various sectors. Further, the replacement of fine aggregates and cement in concrete with various proportions of powdered glass is an engrossing topic among researchers for over a decade. The present study aims to the optimal use of glass powder in concrete as a replacement for cement and to enhance the characteristics compressive strength when compared to conventional concrete. Cement was replaced by various percentages of fine glass powder ranging from 10-50 % at an increment of 10%. The concrete cube specimens for 7 and 28 days were evaluated for their compressive strength after curing period, with that of conventional concrete. From the acquired results, it is perceptible that glass powder can be a suitable replacement for cement.

This article describes results of an experimental study on incipient motion of gravel particles present in the cohesive mixtures, i.e. clay–silt–gravel and clay–silt–sand–gravel, in which the percentage of clay varied from 10% to 50% on weight basis. Incipient motion condition is visually and quantitatively identified which responds to sheet and line erosion type appearance on the top surface of the channel bed for clay up to 30% and mass erosion pattern for 40% and 50% of clay. The clay percentage, weighted geometric standard deviation and bulk density of the cohesive sediment mixture are found to be the main parameters that affect the incipient motion of gravel particles. A functional relationship is proposed to determine critical shear stress of gravel particles present in cohesive sediment mixtures. The regression analyses as well as goodness of fit test were conducted for the proposed relationships which were found to be in good agreement with the present data.

Collecting Bayesian material scattered throughout the literature, this volume examines the latest methodological and applied aspects of Bayesian statistics. The book covers biostatistics, econometrics, reliability and risk analysis, spatial statistics, image analysis, shape analysis, Bayesian computation, clustering, uncertainty assessment, high-energy astrophysics, neural networking, fuzzy information, objective Bayesian methodologies, empirical Bayes methods, small area estimation, and many more topics. Each chapter is self-contained, gives an overview of the area, presents theoretical insights, and emphasizes applications through motivating examples.