Shaft Height Research Articles

Analytical models for evaluating buoyancy-driven ventilation due to stack effect in a shaft considering heat transfer from shaft interior boundaries

Stack effect is a dominant driving force for building natural ventilation. Analytical models were developed for the evaluation of stack effect in a shaft, accounting for the heat transfer from shaft interior boundaries. Both the conditions with constant heat flux from boundaries to the airflow and the ones with constant boundary temperature were considered. The prediction capabilities of these analytical models were evaluated by using large eddy simulation (LES) for a hypothetical shaft. The results show that there are fairly good agreements between the predictions of the analytical models and the LES predictions in mass flow rate, vertical temperatures profile and pressure difference as well. Both the results of analytical models and LES show that the neutral plane could locate higher than one half of the shaft height when the upper opening area is identical with the lower opening area. Further, it is also shown that the analytical models perform better than KLOTE’s model does in the mass flow rate prediction.

Experimental Study on the Design of Pressurization System in High-Rise Buildings

By experimental study, a design for pressurization system in a multiple injection system with upper injection is discussed and the velocity distribution in a shaft is educed by the approach method. This velocity has a relation with volume flux from pressurization fan, section area of pressurization shaft and height of shaft. In factual situation, there is an important assistant meaning on researching the design of pressurization system in high-rise buildings.

Study on the Shaft Height of Natural Ventilation Using Smoking Shaft in Urban Tunnel

The characteristics of smoke flow in natural ventilation shaft are studied in this paper, Using the computational fluid dynamics software FDS5.0 to build a 3D model of an urban tunnel with a smoking shaft, Large Eddy Simulation model was used to obtain the structure of flow field and the mass flow rate of natural ventilation at different shaft height, The results show that when the shaft height is low, the driving force of exhaust is weak and the exhaust capacity reduces rapidly, the flow state in shaft is controlled by horizontal inertia force; when the shaft height increase to a critical height, the exhaust effect enhance significantly, the flow state in shaft will change to stack effect control.

Simplified Prediction Method of Stack-Induced Pressure Distribution in High-rise Residential Buildings

This paper presents a simple prediction strategy for estimating the pressure distribution in high-rise residential buildings, using key parameters that affect the magnitude and distribution of stack pressure. The strategy is composed of two procedures: first, the stack pressure is predicted from parameters such as the height of the elevator shaft, the location of the neutral pressure level for each shaft, and the interior temperature of each shaft. Then, the pressure distribution of each floor is calculated using the equivalent leakage areas of the exterior and interior walls, by which finally the pressure difference across the exterior walls can be estimated. To verify the feasibility of this strategy, the predicted pressure differences across exterior walls were compared to measured data of a high-rise residential building with multiple elevator zoning. The results show that this strategy can predict pressure distribution quickly with satisfactory results for both the architectural designer and HVAC engineer.

Delphi process yielded consensus on terminology and research agenda for therapeutic footwear for neuropathic foot

Objective To investigate areas of consensus and disagreement among Dutch physiatrists concerning prescription of therapeutic footwear for the neuropathic foot and to develop a research agenda. Study Design and Setting Forty participants were physiatrists and experts in the field of orthopedic shoe techniques. Four postal Delphi rounds were followed by a final plenary session. Results Forty of the 44 invited experts participated in all postal Delphi rounds, with an overall response of 100%. They achieved consensus on the following. 1. (Dutch) Terminology for two sets of domains and dimensions for the various features of the neuropathic foot and for the shoe characteristics. 2. Application of specific shoe components: insole, shaft, outsole, tongue, and heel. In most features of the neuropathic foot, shaft and outsole domains were linked in the flexibility dimension. 3. Shoe prescriptions for various features of the neuropathic foot in at least four technical domains. Experts disagreed on application of rocker bar and shaft height. In a final conference, 31 experts agreed on a prioritized research agenda. Conclusion An intensive Delphi process yielded consensus on terminology, and determined areas of consensus and disagreement for future research for the various features of the neuropathic foot and the shoe characteristics.

The evaluation of natural ventilation pressure in Korean long road tunnels with vertical shafts

NVP analysis was carried out by the thermodynamic method, which is more accurate than the hydrostatic method. Based on this technique, it was found that the greater the differences are as the height of ventilation shaft, temperature, the larger the natural ventilation pressure generated. It was also found that the NVP with a vertical ventilation shaft was much greater than that without a shaft. The NVP with a vertical ventilation shaft may have benefited from passive ventilation by a cost-efficient contaminant elimination method and even minor emergency control method in a long road tunnel using the longitudinal ventilation system. The airflow caused by the NVP was large enough (up to 29.26 % of mechanical ventilation) to increase the efficiency of the ventilation system. (A) This paper was presented at Safety in the underground space - Proceedings of the ITA-AITES 2006 World Tunnel Congress and the 32nd ITA General Assembly, Seoul, Korea, 22-27 April 2006. For the covering abstract see ITRD E129148. Reprinted with permission from Elsevier.

Alometria de Caryocar brasiliense (Caryocaraceae) em diferentes fisionomias do Parque Estadual da Serra de Caldas Novas, GO

A relação entre o tamanho e a forma em árvores é importante para a compreensão de diferenças adaptativas apresentadas por uma espécie. Variações nesses caracteres refletem respostas às condições ambientais, constituindo uma resposta ao estresse particular experimentado pelos indivíduos de uma espécie. O presente trabalho teve como objetivo analisar as relações alométricas de duas populações de Caryocar brasiliense Camb. presentes em diferentes fisionomias (cerradão e cerrado stricto sensu) do Parque Estadual da Serra de Caldas Novas (PESCAN), situado no estado de Goiás. Em cada ambiente foram amostrados 30 indivíduos de C. brasiliense que apresentavam circunferência a 30 cm do solo maior ou igual a 15 cm. Para cada indivíduo foi medido o diâmetro a 30 cm do solo (DAS30), diâmetro a altura do peito (DAP), altura total e altura do fuste. Para a análise dos dados foram ajustados diferentes modelos de regressão. A relação DAP/DAS entre os dois ambientes foi distinta, revelando uma variação no formato do caule entre os dois ambientes. No cerrado s.s. as árvores apresentaram um formato mais cônico, enquanto no cerradão, foi observado um caule mais cilíndrico. Árvores de C. brasiliense do cerradão apresentaram altura total e do fuste maiores que aquelas de cerrado s.s. devido, possivelmente, à disputa por luz no ambiente. A presença de indivíduos mais altos sugere um maior investimento no crescimento vertical como forma de "fuga" a condições adversas do meio. O fato de indivíduos de Caryocar brasiliense se ajustarem a modelos alométricos distintos para cada ambiente sugere que os fatores ecológicos podem ter um papel restritivo na alometria dessa espécie.

Escolha de caracteres para o melhoramento genético em erva-mate por meio de técnicas multivariadas.

O objetivo deste trabalho foi aplicar a técnica dos componentes principais como suporte para a seleção de caracteres em erva-mate, bem como estimar parâmetros genéticos. Os resultados indicaram ser possível obter sucesso com a seleção para os caracteres avaliados, haja vistos que as herdabilidades foram de magnitude média a alta. O caracter altura do fuste foi o que apresentou maior coeficiente de variação, menor herdabilidade e menor coeficiente de correlação com os demais. Por meio dessa técnica, observou-se que a altura do fuste foi a que menos contribuiu para a variação dos dados, sendo passível de descarte. Verificou-se que os caracteres altura da planta e diâmetro da copa podem representar de maneira satisfatória a variação ocorrida.

Possibilities of counter‐current scrap pre‐heating with melting by use of 100% fossil energy

It shall be found out, how far scrap can be heated without too much oxidation in a shaft with counter‐current flow of scrap and heating gas if the heating gas is stepwise post‐combusted during its rising in the shaft. The scrap is a mixture of plates, cylinders and spheres obeying a log‐normal distribution function of the size. Heat transfer is by convection and radiation. Scrap oxidation kinetics is determined by the phase boundary reaction and by diffusion in the oxide layer. The model calculates the temperature of the scrap size classes and of the gas, and the oxidation of the scrap along the shaft height. The preheated scrap is melted in a smelter. It was found that under steady‐state conditions with a moving scrap heap, about 60% post‐combustion difference between bottom and top of the shaft is possible if the scrap initially has room temperature and is then heated up as far as possible without melting. Scrap oxidation in the shaft is only 0.2% of the production. This is possible by the short residence time of a moving scrap heap in the hot post‐combustion planes where the oxidation rate is high. Calculations for a stationary heap, where the scrap residence time in the hot zones is much longer, showed that here, the oxidation is more than 10 times higher.

Anthropoid phalanges from the Oligocene of Egypt

Proximal phalanges recovered from Oligocene sediments of the Jebel Qatrani Formation, Fayum Province, Egypt, are attributed to the anthropoids Aegyptopithecus and Apidium. A multivariate discriminant function analysis using phalangeal shape indices proved reliable for distinguishing between manual and pedal proximal phalanges of extant primates, and these data can be applied to classify phalanges of fossil primates. Manual and pedal phalanges of Aegyptopithecus show features clearly related to a quadrupedal arboreal lifestyle involving frequent and powerful digital flexion: plantar tubercles are prominent, the flexor sheath ridges are well developed, shaft height increases proximally, shaft cortices are thickest in their distal halves, and the phalanges display strong dorsoventral curvature. Proximal phalanges of Aegyptopithecus resemble those of extant Alouatta, and to a lesser extent those of colobine primates, in these respects. These fossil phalangeal specimens resemble quadrupedal cercopithecids in having large palmar and plantar tubercles, flaring basal apophyses, robust shafts, and dorsally extended and proximodorsally tilted metacarpal and metatarsal facets. Manual and pedal phalanges of Apidium have straight, robust shafts with cortices of equal thickness throughout, relatively dorsoventrally compressed condyles, weak flexor ridges, and a flared base for insertion of the collateral ligaments and interosseous musculature. These features suggest a locomotor repertoire for Apidium that is well suited for stable digital extension during quadrupedal running on horizontal substrates with little emphasis on grasping capabilities. These features compare most favourably with those of the phalanges of extant Saimiri.

Äußere Stabilisatoren im Fußbereich

The stability in the lateral direction is particularly important in indoor sports as well as tennis, where the frequency of injury at the lateral aspect of the ankle is considerably high (according to various sources between 20-30%). The goal of the present work was to discuss the reasons of instability at the ankle and the effect of external stabilizers. In a number of investigations the stability was measured via film analysis during sports activities in barefoot and shoe conditions. It was concluded that stability and blocking of a movement cannot be regarded as equal. The latter restricts necessary movements of the foot at the ankle and may also provoke large internal forces elsewhere. Negative in respect to stability are stiff and thick shoe soles, positive are: the torsional ability of the sole, softness of the shoe sole edge, the link between the shaft and the sole, shaft height, taping and bracing.

Analytic method of hydraulic calculation of eddy shaft spillways

1. The investigated analytic methods of hydraulic calculation of eddy shaft spillways are based on laws of conservation and, unlike the earlier known ones, take into account not only the size and shape of the water passageway but also contraction of the flow upon entering the spiral chamber from the inlet channel or conduit, hydraulic losses of energy at the entry to the vertical shaft, and the presence here of a zone of equalization of the flow. In calculating the characteristics of the swirled flow over the height of the vertical shaft, its potential energy related to the effect of centrifugal body forces is taken into account. 2. The investigated methods make it possible to obtain the calculated values of hydraulic characteristics of eddy shaft spillways and functions of the variation of the parameters of swirled flows in vertical shafts most closely coinciding with the experimental data. The deviations between experiment and calculation lie within the measurement accuracy. This enables recommending the given methods for practical use when designing eddy shaft spillways and for predicting and analyzing their operation.

Dynamic measurement of pressure distribution with flexible measuring mats--an innovative measuring procedure in sports orthopedics and traumatology. Development--use--value

The results of this study provide the basis for an on-target use of measurement of pressure distribution with flexible mats in sports orthopaedics and traumatology and adjacent overlapping fields. Dynamic measurement of pressure distribution using a flexible mat as a capacitor can yield valuable additional information not available so far in this form, on the static and dynamic stress acting on the human locomotor system. In the future this method can be used to prevent injuries and to optimise performance in many disciplines of sport and will make a significant contribution to optimised treatment concepts with pressure-adjusted shoes or insoles, as well as to the control of functional surgery results in traumatology. The fundamentals are presented via a detailed description of the development, standardization and testing of this innovative measuring method. The questions of applicability, practicability and information supplied are discussed on the basis of extensive studies on reproducibility, on the amount of time and technical effort required for each measurement, and on a critical comparison with other methods. For the two fields of application presented here it was possible to standardize the working procedure enabling a largely problem-free application in practice. The first useful results were obtained in sports orthopaedics (alpine ski boots and sportshoe design). By applying the measuring of pressure distribution in alpine ski sports the influence the construction of ski boots on the stress exercised on the human leg could be objectively quantified in man for the first time. Marked differences were found between models where the heel can be turned down on entering, to conventionally fastened ski boots. This, as well as the results on the influence temperature, height of shaft and shaft stability or rigidity on the pressure distribution along the tibia, provide the basis for a new guideline for the testing of ski boots. A new method was developed for the quality testing of shoes, insoles and sport shoes. This method enables for the first time dynamic pressure measurements inside the shoe and under the foot within the shoe. First results have been obtained with different insoles and arch supports or instep-raisers, or with different shoe constructions in general. These results are discussed in respect of their importance for an assessment of the stress exercised on the human body, for a timely detection of unfavourable stress distribution, and for optimizing the performance by means of selecting the appropriate material and suitable design and construction.