Laboratory design-studies of the effect of waves on a proposed island site for a combined nuclear power and desalting plant

There were four major objectives to this investigation: 1) the determination of the degree of stability of the island face when constructed of armor units of various weights; 2) the run-up for a two-dimensional wave system impinging on the island face; 3) the run-up envelope on the four sides of the island in a three-dimensional model; and 4) the wave patterns caused by the effect of the island on its wave environment. Models having three different length scales were tested in the wave tank (1:50, 1:45, and 1:40) and these models are referred to as the two-dimensional models. One model was tested in the wave basin at an undistorted scale of 1:150 and it is referred to in this report as the three-dimensional model. The first two-dimensional model was built to a scale of 1:50 and essentially corresponded to the original design proposed by Omar Lillevang, Consulting Engineer to the Bechtel Corporation. The prototype tribar weight, equivalent to the model tribar used, was 18.9 tons. This structure was stable; however, it was overtopped by waves. With an increase in the crest elevation from +30 ft. to +40 ft. some overtopping was still experienced. The second model was built at an increased scale, 1:40. At the same time the composite slope which existed in the original design was changed so that the island face had a continuous slope of 3 horizontal to 1 vertical with the crest of the defense at elevation +40 ft. This particular model scale was chosen so that, according to the literature, the tribars would be at a condition of incipient failure for high waves. Since the same armor units were used in this model as were used in the 1:50 scale model, the increase in model scale reduced the equivalent weight of the tribars to 9.7 tons and the maximum weight of the armor rock "B" from 10 tons to 5.1 tons. The prototype structure which corresponds to this model was found to be unstable, as expected. It was observed in testing that a critical feature of the construction which contributes to the stability of the structure is the degree to which the cap-rock section is interlocked with the tribar section. The modification made to the slope of the island face and the increased crest elevation eliminated the problem of overtopping, and the maximum run-up for a 14-sec. wave was to elevation +38 ft. Since the model having a 1:40 length scale was unstable and that with a scale of 1:50 was stable, a third model was constructed with a model scale between these two values, a scale of 1:45. The equivalent prototype tribar weight and the maximum weight of the "B" rock for this third model, still using the same model armor units, were increased to 13.8 tons and 7.3 tons respectively by this change. The slope of the wave defense and the crest elevation were the same for this structure as they were in the 1:40 scale model, i. e., a continuous slope of the island face of 3 horizontal to 1 vertical and a crest elevation of +40 ft. This model was satisfactory both with respect to stability and to run-up. Run-up measurements were made for waves of various heights at wave periods of 16 sec., 14 sec., and 12 sec. The maximum run-up was to elevations +39 ft., +35 ft., and +31 ft. respectively for these three wave periods. The three-dimensional model of the ocean bottom and the island was built to an undistorted scale of 1:150 with the island constructed the same as the 1:45 scale two-dimensional model. In these tests in the large wave basin the wave direction was varied as well as the wave period and wave height. The run-up envelopes obtained showed that, for comparable wave heights, the worst condition of run-up was for normally incident waves impinging on the seaward face of the island. The run-up measured for the normally incident direction was usually approximately 10% less than the run-up in the two-dimensional model for the same wave periods and wave heights. For the case of oblique wave incidence the maximum run-up was at the island corner first attacked by the wave with the run-up decreasing with distance from this corner, and this run-up was comparable to the maximum run-up experienced at normal wave incidence. However, the maximum average run up for the oblique case was significantly less than that experienced in the case of normal wave incidence. The run-up on the shoreward face of the island for all wave directions was of the order of 1/10th of that experienced on the seaward face. Detailed observations of the wave pattern in the lee of the island indicated that there were regions near the beach where the currents were in a direction opposite to the observed general current. From overhead photographs it was found that generally this occurred in regions where the waves which diffract from around the sides of the island intersect. Measurements were made of the maximum elevation of the water surface in the region of the causeway for the case of oblique wave incidence

Laboratory studies of the roughness and suspended load of alluvial streams

This report describes research work done under Contract No. DA-25-075-eng-3866 with the U. S. Army, Corps of Engineers, Missouri River Division, Omaha, during the period 1954-1957, on problems of suspended load transport in alluvial streams. A total of 94 experimental runs were made in two laboratory flumes charged with fine sand of several size distributions. Special attention was given to the variation of the friction factor caused by the changing bed configuration and the damping effect of suspended sediment. The relationship between the sediment transportation rate and the hydraulic variables was also investigated. Most of the runs (General Studies, Chap. V) were made with the bed of the flume completely covered with loose sand but some special runs (Special Studies, Chap. VII) were made with the sand bed chemically solidified in place to prevent sediment transport while preserving the bed configuration previously generated by a natural flow of the same velocity with loose sand. The principal laboratory results are as follows: 1. The friction factor f for a stream with a movable sand bed may vary several fold, being highest at low or medium flow velocities and lowest at high velocity. 2. The principal cause of the variation in f is the appearance of dunes at low or medium velocities and disappearance at high velocities. 3. A secondary cause for the reduction in f for high sediment transport rates is the damping effect of the suspended sediment on the turbulence, and the concomitant reduction in the turbulent diffusion coefficients. The maximum observed reduction due directly to the sediment load was only about 28 percent. 4. The discharge and sediment transportation rate are not unique functions of depth and slope because of the variable roughness. Slope (or shear) must probably be considered a dependent variable for alluvial streams because several equilibrium flows can yield the same slope and shear stress. The laboratory data are compared with similar data for natural streams, and the most promising existing analyses for roughness and sediment load are discussed in the light of the present findings. In addition, a critical review of early and recent literature on the resistance of sediment-laden streams is presented in Chapter II

Structure-function studies of MICAL, the unusual multidomain flavoenzyme involved in actin cytoskeleton dynamics

MICAL (from the Molecule Interacting with CasL) indicates a family of multidomain proteins conserved from insects to humans, which are increasingly attracting attention for their participation in the control of actin cytoskeleton dynamics, and, therefore, in the several related key processes in health and disease. MICAL is unique among actin binding proteins because it catalyzes a NADPH-dependent F-actin depolymerizing reaction. This unprecedented reaction is associated with its N-terminal FAD-containing domain that is structurally related to p-hydroxybenzoate hydroxylase, the prototype of aromatic monooxygenases, but catalyzes a strong NADPH oxidase activity in the free state. This review will focus on the known structural and functional properties of MICAL forms in order to provide an overview of the arguments supporting the current hypotheses on the possible mechanism of action of MICAL in the free and F-actin bound state, on the modulating effect of the CH, LIM, and C-terminal domains that follow the catalytic flavoprotein domain on the MICAL activities, as well as that of small molecules and proteins interacting with MICAL

A Summary of Sediment Transportation Mechanics

The development of the mechanics of transportation of sediment by fluids has been carried on mainly in connection with the control and development of streams where its greatest economic importance lies. The difficulties of controlling rivers are concerned largely with such matters as the ability of the flow to erode the banks and bed or the possibility of aggradation due to insufficient transporting capacity. Thus, stream control problems are to a great extent problems in sediment transportation. Although sediment transportation is closely identified with streams, its application is by no means limited to this field. It is of importance in many industrial processes where solids are transported by liquids or gases or where solids need to be mixed and/or separated from fluids, and in the important field of transportation of soil by wind. In this paper a brief outline will be given of the mechanics underlying this subject. No attempt will be made to discuss the many important practical problems which provided the incentive for developing this special branch of fluid mechanics

Technique and expression in Carl Czerny's teaching: a critical study of Czerny's Piano-Forte School, Opus 500, demonstrating the direct relation between mechanical teaching and expression in performance

Carl Czerny (1791–1857) lived at the turn of the nineteenth century, when the piano underwent significant development as an instrument, and subsequently generated a huge repertoire. While Czerny is mostly remembered for his piano exercises and etudes, his writings about music as well as his works in serious style reveal a man with a sophisticated awareness of the importance of piano technique, entwined with profound musical ideas and an understanding of music that make him a forerunner of the romantic style. This study focuses on Czerny’s Opus 500 Complete Theoretical and Practical Piano Forte School (1839), and its Supplement (1845). Through analysis of the tutorial’s content it attempts to prove the deep connection between piano technique and expressive playing in Czerny’s teaching. The first five chapters of this work compare elements of expressive playing, such as articulation, dynamics and tempo, as presented in different tutorials written before Czerny’s opus 500, clearly relevant to Czerny. The remaining chapters of this study discuss the pedagogical path that Czerny suggests to master those same aspects, especially through scales and scale-based exercises, and through constant attention to improving the listening skills of the student. The purpose of this work is to reassess Czerny as a key figure of modern piano technique, as a teacher and pedagogue able to introduce pianists to mechanical training while honing the essential skills to perform any piece of music in any style expressively

Lecture notes on sediment transportation and channel stability

These notes have been prepared for a series of lectures on sediment transportation and channel stability given by the authors to a group of engineers and geologists of the U. S. Department of Agriculture assembled at Caltech on September 12-16,1960. The material herein is not intended to serve as a complete textbook, because it covers only subjects of the one-week sequence of lectures Due to limitation of space and time, coverage of many subjects is brief and others are omitted altogether. At the end of each chapter the reader will find a selected list of references for more detailed study

Measurements of critical shear stress for entraining fine sediments in a boundary layer

Experiments were made in a flume 15-3/8 in. wide by 12 ft long to determine the shear stress for critical motion of fine sediment in a growing boundary layer. Determinations were made for two sediments, a quartz sand with geometric mean sieve size of 0. 102 mm and glass beads with geometric mean sedimentation diameter of 0. 037 mm. The intensity of sediment motion was judged from the frequency of bursts of motion over a small area varying from 7 to 18 mm in diameter. When the burst frequency fell between 1/3 and 1 burst per second, critical conditions for inception of motion were considered to obtain. Values of shear velocity, u_*, and bed shear stress, τ_0, for turbulent flow were determined from measured velocity profile data by essentially two methods. In the first the slope, N, of a straight line fitted to a semilogarithmic graph of velocity profile data was used in Eq. (8) to obtain u_*. In the other, values of point velocity, u, at a distance of .03 ft from the bed was substituted into the logarithmic equation for velocity distribution at a smooth wall, Eq. ( 5 ) , to obtain u_*. The data obtained from Eq. (8) and plotted on Fig. 14a show wider scatter than those calculated from Eq. (5) and plotted on Fig. 14b. The data obtained by means of Eq. (5) are considered the more reliable and are presented on a complete Shields diagram in Fig. 15

Sediment studies in the Brazilian Amazon River Basin

The work was to be carried out as part of WMO's participation in the United Nations Development Project (UNDP) on Hydrology and Climatology of the Brazilian Amazon River Basin under the direction of Eduardo Basso, Project Manager. This project is carried out in cooperation with The General Directorate for Amazon Development of the Brazilian Government (SUDAM)