scholarly journals THE RELATIONSHIP BETWEEN WAVE ACTION AND BEACH PROFILE CHARACTERISTICS

2011 ◽  
Vol 1 (7) ◽  
pp. 14 ◽  
Author(s):  
P.H. Kemp
Keyword(s):  
Rational Design ◽  
Break Point ◽  
Coarse Sand ◽  
Beach Erosion ◽  
Beach Profile ◽  
Model Study ◽  
Materials Used ◽  
Profile Characteristics ◽  
The Relationship ◽  
The Waves

The rational design of coast protection works requires a knowledge of the behaviour of the beach under natural conditions. The understanding of the relationship between the waves acting on the beach and the characteristics of the beach profile produced, is thus a necessary preliminary to the analysis of the causes of beach erosion and the evaluation of the effect of projected remedial measures. The present paper describes the results of a series of preliminary hydraulic model experiments carried out by the author prior to a model study of the behaviour of groynes in stabilising beaches. Most of the beach materials used represented coarse sand or shingle in nature. The results demonstrate the fundamental importance of the "phase difference" in terms of wave period between the break-point and the limit of uprush, in relation to flow conditions, cusp formation, and the change from "step" to "bar" type profiles. Within the limits of the experiments an expression connecting the breaker height, beach profile length, and grain diameter is developed, and its implications examined in relation to beach slope, and to the previous "wave steepness" criterion for the change from step to bar type profiles. Observations are included on the rate of recession of a shoreline due to the onset of more severe wave conditions.

scholarly journals A MODEL STUDY OF THE DISTRIBUTION OF RUN-UP OF WIND-GENERATED WAVES ON SLOPING SEA WALLS

1968 ◽  
Vol 1 (11) ◽  
pp. 56 ◽  
Author(s):  
Norman B. Webber ◽  
Geoffrey N. Bullock
Keyword(s):  
Wind Wave ◽  
Wave Flume ◽  
Model Study ◽  
Wind Velocities ◽  
Wave Heights ◽  
Instantaneous Values ◽  
Statistical Relationships ◽  
Run Up ◽  
The Relationship ◽  
The Waves

The behaviour of wind-generated waves on impermeable slopes of 1:2, 1:4 and 1:10 was investigated in a 40 ft long laboratory wind-wave flume. Apparatus for measuring instantaneous values of the run-up was devised. Wind velocities of up to 44 ft/sec were applied, producing wave heights of up to 2.5 in. Distributions were obtained for the wave and run-up characteristics. The empirical results were compared with theoretical statistical relationships. A comparison was made with the run-ups in paddle-wave experiments. The relationship between the waves and their run-ups was further investigated by a comparison of simultaneous recordings, using the methods of spectral analysis.

scholarly journals EFFECTS OF NONUNIFORM WAVE ENERGY IN THE LITTORAL ZONE

1970 ◽  
Vol 1 (12) ◽  
pp. 47
Author(s):  
Victor Goldsmith ◽  
Joseph M. Colonell
Keyword(s):  
Wave Energy ◽  
Beach Erosion ◽  
Cape Cod ◽  
Beach Profile ◽  
Wave Refraction ◽  
Close Relationship ◽  
Erosion And Accretion ◽  
Ebb Tidal Delta ◽  
The Waves ◽  
Nonuniform Wave

Bi-weekly monitoring of four closely-spaced permanent beach profile stations located on the northeast end of Monomoy Island (Cape Cod) has revealed major variations in the amount of erosion and accretion occurring along this portion of the Massachusetts shoreline During the 27-month monitoring period a close relationship was observed between changes in the beach and offshore portions of the profiles Three distinct types of bars were noted (1) Subtidal bars which are parallel to the shoreline and located one to two thousand feet off those portions of the shoreline undergoing relatively small amounts of beach erosion, (2) Subtidal bars which are perpendicular to the shoreline and attached to areas of the shore undergoing large amounts of erosion, and (3) Large intertidal bars which are oriented obliquely to the shoreline and associated with the formation of the ebb-tidal delta and the resulting wave refraction patterns The large variations in erosion and accretion occurring along the beach at any one time are related to the nonumform distribution of energy within the waves arriving at this section of the coastline This nonunifortuity of wave energy is attributed to refraction of the waves around the irregular bathymetry offshore from Monomoy, and it appears to produce shoreline protuberances of sand which are flanked updrift and downdrift by erosional zones.

scholarly journals THE EFFECT OF WAVES ON THE PROFILE OF A NATURAL BEACH

1968 ◽  
Vol 1 (11) ◽  
pp. 23
Author(s):  
Warren C. Thompson ◽  
John C. Harlett
Keyword(s):  
Field Data ◽  
Initial Conditions ◽  
Empirical Relationship ◽  
Wave Power ◽  
Wave Steepness ◽  
Beach Profile ◽  
Wave Parameters ◽  
Equilibrium Profiles ◽  
The Relationship ◽  
The Waves

A 60-day field study was conducted on a selected natural beach in which the beach profile was measured daily and the waves incident upon the profile were recorded continuously. Beach and wave parameters derived from the field data were empirically combined to yield: (a) quantitative relationships between the change in the profile and the-average deepwater wave steepness and wave power over a lunar day (24.8 hours) given the profile at the beginning of the period, (b) equilibrium profiles for different values of wave steepness, (c) an empirical relationship between wave steepness and wave power which agrees well with theory, and (d) rates at which the beach profile approached equilibrium for given initial conditions of non-equilibrium. Using the relationship developed between beach change and wave steepness, hindcasts were made of the day-to-day sand elevation at a selected location near the middle of the profile and were found to agree fairly well with the observed sand level.

scholarly journals Correlation between Defects and Technical Wear of Materials Used in Traditional Construction

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2482
Author(s):  
Jarosław Konior ◽  
Mariusz Rejment
Keyword(s):  
Residential Buildings ◽  
Descriptive Analysis ◽  
Technical Condition ◽  
Water Penetration ◽  
Major Drawback ◽  
Wear Process ◽  
Materials Used ◽  
Traditional Construction ◽  
The Relationship ◽  
Measurable Property

The degree of technical wear of old buildings, which are made of basic materials (cement, concrete, steel, timber, plaster, brick) using traditional technology, is expressed by the size and intensity of damage to their elements. The topic of the research concerns old residential buildings from the turn of the 19th and 20th centuries, which are located in the downtown district of Wroclaw, Poland. The descriptive analysis and the analysis of the definitions of defects that occur in the elements of residential buildings, which were performed as random analyzes, do not allow defects to be considered as measurable variables at a level of visual investigation. The major drawback of the method that is used by experts when assessing the technical condition of civil engineering buildings is that it does not numerically express the magnitude (strength) of the defects. Therefore, an attempt was made to numerically express the relationship (if such a relationship exists) between the occurred defects of buildings and the extent of their technical wear process. When calculating the strength of this relationship, the method of determining the point biserial correlation coefficient for the measurable property and the dichotomous property was used. It was found that the direction of the relation is right-hand for all the tested building elements, but the strength of the correlation between the detected defects and technical wear shows a considerable span and depends on the conditions of the apartment house’s maintenance. As a rule, damage caused by water penetration and moisture penetration always shows correlations of at least moderate strength.

scholarly journals Cryo-EM structure of mycobacterial cytochrome bd reveals two oxygen access channels

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Weiwei Wang ◽  
Yan Gao ◽  
Yanting Tang ◽  
Xiaoting Zhou ◽  
Yuezheng Lai ◽  
...  
Keyword(s):  
Rational Design ◽  
Pathogenic Bacteria ◽  
Structural Topology ◽  
Antimicrobial Drugs ◽  
E Coli ◽  
Cytochrome Bd ◽  
Cryo Electron Microscopy ◽  
Functional Mechanisms ◽  
The Relationship ◽  
Potential Oxygen

AbstractCytochromes bd are ubiquitous amongst prokaryotes including many human-pathogenic bacteria. Such complexes are targets for the development of antimicrobial drugs. However, an understanding of the relationship between the structure and functional mechanisms of these oxidases is incomplete. Here, we have determined the 2.8 Å structure of Mycobacterium smegmatis cytochrome bd by single-particle cryo-electron microscopy. This bd oxidase consists of two subunits CydA and CydB, that adopt a pseudo two-fold symmetrical arrangement. The structural topology of its Q-loop domain, whose function is to bind the substrate, quinol, is significantly different compared to the C-terminal region reported for cytochromes bd from Geobacillus thermodenitrificans (G. th) and Escherichia coli (E. coli). In addition, we have identified two potential oxygen access channels in the structure and shown that similar tunnels also exist in G. th and E. coli cytochromes bd. This study provides insights to develop a framework for the rational design of antituberculosis compounds that block the oxygen access channels of this oxidase.

Pots on mats: mat-impressed salt-extraction pottery at Chalcolithic Provadia-Solnitsata, Bulgaria

Antiquity ◽  
2021 ◽  
pp. 1-16
Author(s):  
Mila Andonova ◽  
Vassil Nikolov
Keyword(s):  
Material Culture ◽  
Large Scale ◽  
Raw Materials ◽  
Salt Production ◽  
Production And Consumption ◽  
Late Chalcolithic ◽  
South Eastern Europe ◽  
Materials Used ◽  
The Relationship

Evidence for both basket weaving and salt production is often elusive in the prehistoric archaeological record. An assemblage of Middle–Late Chalcolithic pottery from Provadia-Solnitsata in Bulgaria provides insight into these two different technologies and the relationship between them. The authors analyse sherds from vessels used in large-scale salt production, the bases of which bear the impression of woven mats. This analysis reveals the possible raw materials used in mat weaving at Provadia-Solnitsata and allows interpretation of the role of these mats in salt production at the site. The results illustrate how it is possible to see the ‘invisible’ material culture of prehistoric south-eastern Europe and its importance for production and consumption.

scholarly journals Physical model study of beach profile evolution by sea level rise in the presence of seawalls

2018 ◽  
Vol 136 ◽  
pp. 172-182 ◽  
Author(s):  
T. Beuzen ◽  
I.L. Turner ◽  
C.E. Blenkinsopp ◽  
A. Atkinson ◽  
F. Flocard ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Physical Model ◽  
Sea Level ◽  
Beach Profile ◽  
Model Study

scholarly journals A Study on the Relationship of Profile Characteristics with Group Performance of Tribal Farmer Interest Groups (FIGs)

2021 ◽  
Vol 108 (March) ◽  
pp. 1-6
Author(s):  
Mathuabirami V ◽  
◽  
Kalaivani S ◽  
Keyword(s):  
Interest Groups ◽  
Group Performance ◽  
Group Communication ◽  
Total Sample ◽  
Structured Interview ◽  
Group Leadership ◽  
Medium Level ◽  
Profile Characteristics ◽  
Relationship Of ◽  
The Relationship

The present study aimed to analyze the relationship of profile characteristics with group performance of tribal FIGs. The survey was purposively conducted in Erode district as it contains more number of tribal Farmer Interest Groups (FIGs). A total of five Tribal FIGs were randomly selected from 16 Tribal FIGs belonging to Dhimbam Dhaniya Farmer Producer Company Limited (DDFPCL) and the total sample size was 100. A well-structured interview schedule was prepared and employed to collect the data from the respondents. The findings showed that majority of the respondents were young aged with high school education, female marginal farmers receiving low level of annual income with medium level of farming experience. They had also received medium level of support from institution. The findings of the study also revealed that majority of the members of tribal FIGs had 76.00, 75.00, 73.00, 67.00 and 55.00 percentages of self-confidence, economic motivation, group leadership, group communication and information seeking behaviour respectively.To improve the performance of tribal FIGs, measures should be taken to increase the level of group communication, group leadership and group cohesiveness. This can be increased through organizing regular meetings for members, proper selection of leaders and making the members to understand the importance of group action

Epilogue

2021 ◽  
pp. 1249-1278
Author(s):  
Frederick Cooper
Keyword(s):  
Twentieth Century ◽  
World War Ii ◽  
World Order ◽  
Break Point ◽  
The United States ◽  
Political Movements ◽  
Territorial State ◽  
Late Twentieth ◽  
Ancient Times ◽  
The Relationship

“Beyond Empire” asks what studying empires from ancient times to the twentieth century tells us about the world today. Crises in the Middle East and the configuration of Europe, China, Africa, the United States, and elsewhere bear the imprint of trajectories into, through, and out of empire. Instead of assuming the “empire-to-nation-state” narrative, it explores the articulations of empire and nation and makes clear that the relationship was uncertain and contested, even in the mid- and late twentieth century. New empires (USSR, Japan, Nazi Germany) arose even as others collapsed, but World War II constituted a break point for winning as well as defeated empires, creating openings to anti-colonial movements but also enabling Western European powers to imagine a future without needing imperial resources in their rivalry with each other. The independent territorial state was not the only objective of political movements in colonial empires, but in the end national independence was what they could get. The juridical equivalence of post-imperial states has not brought about a stable, equitable, or even predictable world order.

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