The impact of temperature and humidity variations on the resulting frequencies of metal flue pipes in pipe-organs: An analytical model

2021 ◽  
Vol 149 (4) ◽  
pp. A122-A122
Author(s):  
Piergiovanni Domenighini
2019 ◽  
Vol 9 (4) ◽  
pp. 504-511
Author(s):  
Sikha Mishra ◽  
Urmila Bhanja ◽  
Guru Prasad Mishra

Introduction: A new analytical model is designed for Workfunction Modulated Rectangular Recessed Channel-Silicon On Insulator (WMRRC-SOI) MOSFET that considers the concept of groove gate and implements an idea of workfunction engineering. Methods: The impact of Negative Junction Depth (NJD) and oxide thickness (tox) are analyzed on device performances such as Sub-threshold Slope (SS), Drain Induced Barrier Lowering (DIBL) and threshold voltage. Results: The results of the proposed work are evaluated with the Rectangular Recessed Channel-Silicon On Insulator (RRC-SOI) MOSFET keeping the metal workfunction constant throughout the gate region. Furthermore, an analytical model is developed using 2D Poisson’s equation and threshold voltage is estimated in terms of minimum surface potential. Conclusion: In this work, the impact of Negative Junction Depth (NJD) on minimum surface potential and the drain current are also evaluated. It is observed from the analysis that the analog switching performance of WMRRC-SOI MOSFET surpasses RRC-SOI MOSFET in terms of better driving capability, high Ion/Ioff ratio, minimized Short Channel Effects (SCEs) and hot carrier immunity. Results are simulated using 2D Sentaurus TCAD simulator for validation of the proposed structure.


2021 ◽  
pp. 174425912098418
Author(s):  
Toivo Säwén ◽  
Martina Stockhaus ◽  
Carl-Eric Hagentoft ◽  
Nora Schjøth Bunkholt ◽  
Paula Wahlgren

Timber roof constructions are commonly ventilated through an air cavity beneath the roof sheathing in order to remove heat and moisture from the construction. The driving forces for this ventilation are wind pressure and thermal buoyancy. The wind driven ventilation has been studied extensively, while models for predicting buoyant flow are less developed. In the present study, a novel analytical model is presented to predict the air flow caused by thermal buoyancy in a ventilated roof construction. The model provides means to calculate the cavity Rayleigh number for the roof construction, which is then correlated with the air flow rate. The model predictions are compared to the results of an experimental and a numerical study examining the effect of different cavity designs and inclinations on the air flow rate in a ventilated roof subjected to varying heat loads. Over 80 different test set-ups, the analytical model was found to replicate both experimental and numerical results within an acceptable margin. The effect of an increased total roof height, air cavity height and solar heat load for a given construction is an increased air flow rate through the air cavity. On average, the analytical model predicts a 3% higher air flow rate than found in the numerical study, and a 20% lower air flow rate than found in the experimental study, for comparable test set-ups. The model provided can be used to predict the air flow rate in cavities of varying design, and to quantify the impact of suggested roof design changes. The result can be used as a basis for estimating the moisture safety of a roof construction.


2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
Javaid Ahmad ◽  
Shaohong Cheng ◽  
Faouzi Ghrib

Dynamic behaviour of cable networks is highly dependent on the installation location, stiffness, and damping of cross-ties. Thus, these are the important design parameters for a cable network. While the effects of the former two on the network response have been investigated to some extent in the past, the impact of cross-tie damping has rarely been addressed. To comprehend our knowledge of mechanics associated with cable networks, in the current study, an analytical model of a cable network will be proposed by taking into account both cross-tie stiffness and damping. In addition, the damping property of main cables in the network will also be considered in the formulation. This would allow exploring not only the effectiveness of a cross-tie design on enhancing the in-plane stiffness of a constituted cable network, but also its energy dissipation capacity. The proposed analytical model will be applied to networks with different configurations. The influence of cross-tie stiffness and damping on the modal response of various types of networks will be investigated by using the corresponding undamped rigid cross-tie network as a reference base. Results will provide valuable information on the selection of cross-tie properties to achieve more effective cable vibration control.


2018 ◽  
Vol 2018 ◽  
pp. 1-7
Author(s):  
A. B. Vallejo-Mora ◽  
M. Toril ◽  
S. Luna-Ramírez ◽  
M. Regueira ◽  
S. Pedraza

UpLink Power Control (ULPC) is a key radio resource management procedure in mobile networks. In this paper, an analytical model for estimating the impact of increasing the nominal power parameter in the ULPC algorithm for the Physical Uplink Shared CHannel (PUSCH) in Long Term Evolution (LTE) is presented. The aim of the model is to predict the effect of changing the nominal power parameter in a cell on the interference and Signal-to-Interference-plus-Noise Ratio (SINR) of that cell and its neighbors from network statistics. Model assessment is carried out by means of a field trial where the nominal power parameter is increased in some cells of a live LTE network. Results show that the proposed model achieves reasonable estimation accuracy, provided uplink traffic does not change significantly.


2005 ◽  
Vol 133 (5) ◽  
pp. 1384-1402 ◽  
Author(s):  
Hann-Ming Henry Juang ◽  
Ching-Teng Lee ◽  
Yongxin Zhang ◽  
Yucheng Song ◽  
Ming-Chin Wu ◽  
...  

Abstract The National Centers for Environmental Prediction regional spectral model and mesoscale spectral model (NCEP RSM/MSM) use a spectral computation on perturbation. The perturbation is defined as a deviation between RSM/MSM forecast value and their outer model or analysis value on model sigma-coordinate surfaces. The horizontal diffusion used in the models applies perturbation diffusion in spectral space on model sigma-coordinate surfaces. However, because of the large difference between RSM/MSM and their outer model or analysis terrains, the perturbation on sigma surfaces could be large over steep mountain areas as horizontal resolution increases. This large perturbation could introduce systematical error due to artificial vertical mixing from horizontal diffusion on sigma surface for variables with strong vertical stratification, such as temperature and humidity. This nonnegligible error would eventually ruin the forecast and simulation results over mountain areas in high-resolution modeling. To avoid the erroneous vertical mixing on the systematic perturbation, a coordinate transformation is applied in deriving a horizontal diffusion on pressure surface from the variables provided on terrain-following sigma coordinates. Three cases are selected to illustrate the impact of the horizontal diffusion on pressure surfaces, which reduces or eliminates numerical errors of mesoscale modeling over mountain areas. These cases address concerns from all aspects, including unstable and stable synoptic conditions, moist and dry atmospheric settings, weather and climate integrations, hydrostatic and nonhydrostatic modeling, and island and continental orography. After implementing the horizontal diffusion on pressure surfaces for temperature and humidity, the results show better rainfall and flow pattern simulations when compared to observations. Horizontal diffusion corrects the warming, moistening, excessive rainfall, and convergent flow patterns around high mountains under unstable and moist synoptic conditions and corrects the cooling, drying, and divergent flow patterns under stable and dry synoptic settings.


2021 ◽  
Vol 98 (6) ◽  
pp. 43-49
Author(s):  
V.B. DOROKHOV ◽  
◽  
N.YU. PINTELIN ◽  
D.YU. ZHELDAKOV ◽  
◽  
...  

The heat and humidity regime of the buried parts can be essential, and sometimes crucial, for the normalization of the microclimate of the entire monument. The experience of thermophysical studies in church architectural monuments shows a wide range of factors that determine the impact of the temperature and humidity regime of the buried volumes on the formation of conditions for the preservation of the monument as a whole. Currently, the Climate Laboratory of Museums and Architectural Monuments of GOSNIIR conducts research on this problem in order to create a methodology for studying and normalizing the heat and humidity regime of the aboveground and underground parts of the building as a whole to develop design and technological approaches to optimizing the conditions for the preservation of the monument. The article considers a practical example of providing heat and humidity conditions for the preservation of a monument with monumental painting.


2013 ◽  
Vol 7 (2) ◽  
pp. 192-206 ◽  
Author(s):  
Jacqueline Elhage Ramis ◽  
Emmanuel Antonio dos Santos

To evaluate airports' current thermal comfort temperature and humidity were registered in three main Brazilian international airports, other variables were local region climate characteristics and the constructive types of passenger terminal buildings. The Brazilian air transportation demand has considerably grown over the last decade, with some airports reaching their capacity. Thermal discomfort may be a key driver of passenger perceptions of airport service levels, specially under capacity overload situations. Therefore, to achieve airport thermal comfort within this new scenario, and with the imminent and future expansions of the airport system, certainly put extra work on the existing air conditioning systems, consequently increasing energy consumption and its associated costs. Collected temperature and humidity from each study case subsided the data for the psychrometric charts. The evidences showed temperatures below the international standards requirements for thermal comfort levels. These charts also indicated that adequate building types with natural air circulation, provides the best levels of thermal comfort. Results suggest the importance of considering the implementation of a combined system using artificial and natural air conditioning in the planning of future expansions.


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