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ABSTRACTNumerous hydraulic structures are to be provided in canals and rivers for storage, diversion and transport of water. Some innovative, economic and improved hydraulic design has been discussed. Transitions are to be provided in all canal structures wherever the canal is flumed to achieve economy. Most popular transition in the USA and Europe is Hinds transition. The author performed large numbers of experiments to introduce short curved transitions at entry and straight expansion at exit to attain higher efficiency and better performance. Energy dissipaters are usually provided with parallel side walls followed by transition structures to connect the stilling basin with normal channel section, resulting in huge cost of the structure. For low value of inflow Froude’s number (F1), the author introduced a new type of energy dissipater with straight diverging side walls starting from toe of the structure so that it functions as both energy dissipater and flow diffuser. Flow metering structures are needed for flow measurement in both rivers and canals. Parshall flumes may be free or submerged. The author invented a new proportional-type flow meter, by simultaneously fluming and raising the bed so that the flow remains free for all discharges in a given range.

AbstractInnumerable falls are to be provided in irrigation canals where ground slope exceeds the permissible bed slope of a canal. In the conventional method of design, fluming ratio is fixed arbitrarily irrespective of inflow Froude’s number. Long lengths of inlet and outlet transitions are provided to prevent flow separation. Transition and dissipation structures are kept separate resulting in high costs. Hydraulic performance of the conventional fall structure is also not so satisfactory. Analytical and experimental studies were conducted by the author to find an efficient and economic method of design of falls. Optimum fluming ratio and optimum length of transitions are found both for economy as well as efficiency. An efficient and economic stilling basin with rapidly diverging side walls and adversely sloping floor, which act simultaneously as energy dissipater and transition, has been recommended. An example has been worked out to illustrate the design procedure of the proposed canal fall.

AbstractEstimation of scour in bridge piers is necessary for economic and safe design of bridges. Although a large number of mathematical models are available, scour estimation in Indian bridges is done by empirical equation like Lacey in both fine and coarse soil. Total scour depths in piers, founded on fine soil, are estimated in five bridges in India using different mathematical models and are compared with those found by IRC method based on Lacey’s theory. IRC method is found to overestimate scour in all the cases and the error is found to vary between 5 and 275%. Local scour depths in bridge piers founded on coarse soil are observed at five bridge sites in Mississippi river basin in U.S.A. Scour depths observed are compared with those predicted by different mathematical models and also by IRC method. Compared to IRC method, scour in piers founded on coarse soil, governed both by size and gradation of sediments, is found to be significantly less than that in fine uniform soil under all velocity of flow. It is observed that the scour depths predicted by mathematical models are quite conservative and closer to the observed ones.

The paper presents an information-theoretic algorithm for solving constrained non-linear programming problems based upon the principle of minimum cross-entropy and surrogate mathematical programming. It is an alternative to the earlier work by Templeman and Li [4-6] based on the maximum entropy principle and so far as the rate of convergence of the solution is concerned it is an improvement upon it, The merit of the present technique is illustrated with two numerical examples.

Supercritical flow at abrupt expansions W. H. Hager, PhD, and S. K. Mazurnder, PhD W Abrupt channel expansions with supercritical approach floware important elements of outlets and spillways.An experimental study was carried out, in which boththe free surface and the velocity field wereaccounted for. Similarity is found forthe flow surface profiles, whereas the velocity field is affected by a significant scale effect involving the Reynolds number. non-dimensional A approach is used forfurther investigation of the axial and wallsurface profiles. The flow fieldis illustrated by typical photographs, and a generalized design method is presented...

The title compound, 9(R)‐[6(R)‐hydroxy­methyl‐1‐oxa‐4‐thia­cyclo­hexan‐2‐yl]‐1,9‐di­hydro‐6H‐purin‐6‐one–water (4/3), C10H12N4O3S·0.75H2O, crystallizes in the triclinic space group P1 with four mol­ecules in the asymmetric unit and 0.75 waters of hydration per mol­ecule. The structure was refined to an Rvalue of 0.072 for 3382 observed reflections. The four crystallographically independent mol­ecules are designated A, B, Cand D. All four oxa­thia­ne rings adopt the chair conformation and the purine bases are in an antiorientation with respect to the sugar moieties. Molecules Aand Dand mol­ecules Cand Bare base paired by a single hydrogen bond of the type N—H⃛N. These base pairs are again hydrogen bonded to their translated pairs in the direction of a cell diagonal.

In the title compound, oxonium 5‐amino‐2,6‐dioxo‐1,2,3,6‐tetra­hydro­pyrimidine‐4‐sulfonate hydrate, H3O+·­C4H4­N3­O5S−·­H2O, the sulfonate group is in the anionic form and charge balance is provided by an o­xonium cation, H3O+. Screw‐related mol­ecules overlap significantly and are hydrogen bonded to form a zigzag chain of the uracil skeleton along the direction of the cscrew axis. The partially stacked bases and their glide‐related equivalents run parallel to the aaxis to form hydro­phobic zones separated by hydro­philic zones built up by a network of hydrogen bonds.

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