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Slender structures are elegant aesthetically. The insufficiency in knowledge of the real resistance to buckling of very slender reinforced concrete columns leads to an exaggeration of the sizes of the columns. _The examples of concrete compression members cited and constructed in Industry on a global basis suggest that very slender columns have inherent safety both from the point of view of the ultimate strength and stability. The strengths of columns given. by the British codes would seem to be exceeded by many of the long slender reinforced concrete columns and struts which have been used Internationally. Both the theoretical and the experimental short term investigations have been carried out to establish the behaviour of hinged, very slender reinforced concrete columns at various stages'of axial loading. Forty three very slender reinforced concrete columns of two different square cross sections with two sizes of longitudinal reinforcements with lateral ties were cast. Slenderness rates, L A, were varied from 30 to 79. Special factors were obtained to relate the actual modulus of elasticity of concrete in columns at buckling failure to a knowledge of the initial modulus of elasticity of concrete in control cylinder specimens. Both theoretical and experimental graphs of load against moment, made dimensionless for critical sections of columns have been obtained. Dimensionless load-moment interaction diagrams using material failure as the criterion have been superimposed on these graphs to show considerable inherent material strength of the tested columns near buckling collapse failures. A theory using the fundamental approach has, been developed to predict the deflected shape and moments along the, heights of the columns at various stages of loading. The proposed theory predicts with good correlations the experimental deflections and moments of any loading stages of the columns. The theory has been used to obtain the required variables, to arrive at the initial predicted design loads of the investigated columns. Good correlations of the moments derived from observed strains have also been obtained. The developed theory predicts satisfactorily the buckling collapse loads of the columns. Although the theory has been derived for axially I loaded very slender reinforced concrete-columns, it seems to accept satisfactorily eccentricities of up to about 10 mm. This was confirmed after extensive comparisons of the theoretical buckling collapse loads with the applicable tests of other authors. Creep In the columns investigated was discovered to be one of the major factors for serious consideration. This was conclusively revealed from the observations on the last two very long term creep tests on columns. The actual safe sustained loads for these very slender columns of slenderness ratios, L/H, between 40 and 79 seem to be between 33% and 19% of the short term buckling collapse loads. The reduced modulus approach to predict the safe long term sustained loads seems to give reasonable values for L/H ratios of 40 and 50. The recommendations given for the proposed design of very slender reinforced concrete columns seem to be adequate and simple to use in practice. They are further simplified by the derivation of two equations for the reduction factors, R, for the slenderness ratios between 36 and 40 and between 40 and 79 respectively. The investigation has proved that very slender reinforced concrete columns are very dangerous structural members, as they tend to have violent buckling failures. Nevertheless, It must be prudent not to design against disaster at any cost. This Investigation seemed to have enhanced considerably knowledge of the design of very slender reinforced concrete columns.

While wind energy has witnessed faster growth than any other renewable energy source in recent years, two issues—the decreasing availability of large land expanses for new wind farms and transmission difficulties arising from siting wind farms in remote regions far from load centers—have slowed down this growth considerably. Siting wind turbines offshore places the generating capacity closer to population and load centers; thus, reducing grid congestion. Also, at offshore sites, one can expect higher wind speeds, decreased turbulence, and reduced noise and visual impact constraints. Offshore wind turbines that have been built thus far have had foundations (such as monopiles or jacket structures) that have extended to the seabed. Such offshore wind turbines have thus been confined to shallow waters closer to the shore. Sites farther offshore provide better wind resources (i.e., less turbulence and smoother, stronger winds) while also reducing visual impact, noise, etc. However, deeper waters encountered at such sites make bottom-supported turbines less economical. Wind turbines mounted atop floating platforms are, thus, being considered for deeper water offshore sites. Various floating platform concepts are under consideration; the chief differences among them arise from the way they provide stability to counter the large mass of the rotor-nacelle assembly located high above the mean water level. Of these alternative concepts, the spar buoy platform is a deep draft structure with a low center of gravity, below the center of buoyancy. Reliability analysis of a spar buoy-supported floating offshore 5MW wind turbine based on stochastic simulation is the subject of this study. Environmental data from a selected deepwater reference site are employed in the numerical studies. Using time-domain simulations, the dynamic behavior of the coupled platform-turbine system is studied; statistics of tower and rotor loads as well as platform motions are estimated and critical combinations of wind speed and wave height identified. / text

The focus of this work was to develop a general methodology for modeling water quality in coastal waterbodies. The methods were developed in the context of modeling bacterial total maximum daily loads (TMDLs), but the general approach is applicable to a wide variety of pollutants. The study area for this dissertation was the Copano Bay watershed, which is located on the Texas Gulf Coast. The developed approach combines simple modeling techniques, of the type recommended by state and national advisory groups, in a GIS (geographic information system) framework, resulting in a methodical, easily transferred approach. This work addresses coastal systems where water quality is a function of operations in non-tidal rivers, tidal rivers, and bays, combined with the effects of watershed contributions. An uncertainty analysis was done to quantify a subset of the variance in the modeled results. Outcomes from this work include modeling tools, a documented workflow for modeling water quality in coastal watersheds, procedures to quantify the uncertainty associated with the developed approach, insight to the factors affecting water quality in the study area, and mean annual bacterial TMDLs for the impaired waterbodies of the Copano Bay watershed. / text

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Interactions between the aerodynamics and dynamics of bluff bodies are important in many engineering applications, including suspension bridges, tall buildings, oil platforms, wind turbine towers, air drops, and construction with cranes. In the rotorcraft field, bluff bodies are commonly suspended underneath the vehicle by tethers. This approach is often the only practical way to deliver a payload in a reasonable amount of time in disaster relief efforts, search-and-rescue operations, and military operations. However, currently a fundamental understanding of the aerodynamics of these bluff bodies is lacking, and accurate dynamic simulation models for predicting the safe flying speed are not available. In order to address these shortcomings, two main advancements are presented in this thesis. The aerodynamics of several three-dimensional canonical bluff bodies are examined over a range of Reynolds numbers representative of wind-tunnel-scale to full-scale models. Numerical experiments are utilized, with a focus on uncertainty analysis and validation of the computations. Mean and unsteady forces and moments for these bluff bodies have been evaluated, and empirical models of the shear layer characteristics have been extracted to quantify the behaviors and provide predictive capability. In addition, a physics-based reduced-order simulation model has been developed for bluff bodies. The physics-based approach is necessary to ensure that the predicted behavior of new configurations is accurate, and it is made possible by the breakthroughs in three-dimensional bluff body aerodynamics presented in this thesis. The integrated aerodynamic forces and moments and dynamic behavior predicted by model are extensively validated with data from wind tunnels, flight tests, and high-fidelity computations. Furthermore, successful stability predictions for tethered loads are demonstrated. The model is applicable to the simulation of any generic bluff body configuration, is readily extensible, and has low computational cost.

A generalized approximate hand method of analysis is presented for determining the lateral deflections and internal forces in complex multi-storey structures subject to lateral loading. The buildings may include symmetric or asymmetric combinations of coupled walls, rigid frames, shear walls, wall-frames, rigid frames with central walls, frames with single and multi-storey bracing systems as well as cores that are either open or partially closed by floor beams. The deformations taken into account include bending, axial, shear and torsion. / The analysis is based on the continuous medium technique in which the bents in the structure are replaced by idealized assemblies representing their characteristic modes of behaviour. The proposed method is restricted to structures with uniform geometry up the height and linear elastic behaviour of the structural members. / Design equations are presented for the conventional lateral loading cases: a concentrated load at the top of the structure, a uniformly distributed load, and a triangularly distributed load with maximum intensity at the top. The simplicity of this method allows the sway of a structure, the maximum storey sway and its location in the height of the structure to be determined graphically. This procedure enables not only a rapid estimate of the deflections in the structure but together with an assessment of the internal forces it provides a design office method of comparing the efficiencies of different structural alternatives in the preliminary design of tall building structures.

Objective of the study was to identify the characteristics of mobilization and recovery of cardiovascular system in performing anaerobic loads. Results obtained during the study revealed that a significant feature of recovery after physical loads is an adequate recovery sequence of functional indices of cardiovascular system. Being in normal functional state the relation between regulatory and supplying systems recovers first of all. Later on recover the indices of regulatory systems and latest – indices of supplying systems. It is pointed out that in the recovery process after repetitive alactatic loads recovery sequence of cardiovascular indices remains unchanged, however, while performing eight lactatic anaerobic bouts, a tendency of emerges showing that overstepping a certain limit a characteristic feature in sequence of recovery of cardiovascular indices disrupts. The influence of concentrated anaerobic heavy training loads used during the training mezocycle on cardiovascular and muscular systems has been estimated. Evaluation of cardiovascular changes during the 60-s all-out vertical jump test (Bosco test) showed that it is a very difficult task and could be used for the assessment of performance abilities only of well-trained athletes. 30-s all-out test in jumping is enough in duration and an accurate estimation of the functional state of cardiovascular system and body functioning during the exercising can be performed.

RAUMENŲ, ŠIRDIES IR KRAUJAGYSLIŲ SISTEMŲ SINERGIJA FIZINIŲ KRŪVIŲ METU Vytautas Poškaitis Biomedicinos mokslai, Biologija (01 B) Anotacija Aiškinantis centrinių ir periferinių ŠKS mechanizmus ir jų sąveikas žinoma daug tyrimų, tačiau integruojančių viso organizmo sistemų esmines funkcijas visdar trūksta. Aišku, jog didėjant atliekamo krūvio intensyvumui, prasideda širdies funkcijos apribojimai. Parinkus fizinį pratimą skirtingu laipsniu aktyvuojantį didesnę ar mažesnę kūno raumenų dalį taip pat skirtinga seka ir laipsniu aktyvuojami centriniai ir periferiniai kraujotakos reguliavimo mechanizmai. Jų tarpusavio sąveikos klausimas sveikatos stiprinimo srityje yra ypač aktualus. Fizinių pratimų metu aktyvuojant kūno raumenų dalį skirtingu laipsniu Aišku, jog didėjant atliekamo krūvio intensyvumui, prasideda širdies funkcijos apribojimai ar parinkus fizinį pratimą Skirtingu laipsniu ir skirtinga seka aktyvuojami centriniai ir periferinių kraujotakos reguliavimo mechanizmai ir vis tik lieka ypač aktualus jų tarpusavio sąveikos klausimas. Atlikto darbo tikslas – nustatyti sąsajas tarp centrinių ir periferinių ŠKS funkcinių rodiklių kaitos, atliekant globalaus, regioninio pobūdžio, ir lokaliuosius fizinius krūvius. Tyrime dalyvavo 27 savanoriai, praktiškai sveiki, neturintys nusiskundimų vyrai. Darbe panaudoti tyrimo metodai: elektrokardiografija, arterinio kraujo spaudimo matavimas, neinvazinė artimoji infraraudonoji spektroskopija, veloergometrija, fizinio krūvio poveikiai ir... [toliau žr. visą tekstą] / SYRNERGY OF MUSCULAR AND CARIOVASCULAR SYSTEMS WHILE PERFORMING PHYSICAL LOADS Vytautas Poškaitis Biomedical Sciences, Biology (01 B) Summary There are many investigations dealing with interaction between central and peripheral cardiovascular mechanisms, nevertheless it is lack of methods and even data how to integrate main organism functions. It is clear, that during increasing of physical load occur limitations in heart function and it causes different sequence of activation of heart and peripheral systems. Here appear question how those systems interact, what kind of synergy they develop. It is very important in finding healthy individualized exercising way. The aim of the study was to establish the interaction in changes of central and peripheral indices of cardiovascular system while performing the global type, regional type or local physical workouts. Subjects of the study were 27 volunteers: healthy males who take a regular pat in health promotion groups two or three times per week at least two last years. Methods For the assessment of functional indices were used: Bicycle ergometry, Electrocardiography, measurement of ABP, near infrared spectroscopy, model of functional evaluation of body functioning during exercise. Results have show, that functional state of investigated person have essential influence to the individual changes of cardiovascular indexes during physical load and the synergetic interplay between central and peripheral cardiovascular... [to full text]

Didelio meistriškumo krepšininkų ugdymo krūvių išdėstymo racionalumas rengimo makrocikle ir jų įtaka jėgos greitumo rodiklių kaitai išlieka aktualia šiai dienai tyrimo problema. / The rationality of arrangement of educational loads of highly skilled basketball players during preparation macrocycle and their influence on the variation of indices of speed power remains the relevant research problem nowadays.