Academic literature on the topic 'Double-layer flat roof'

Sloping layer is an important level of Flat Roof. It usually have both slope and heat insulation double function. Its thickness is obtained through energy conservation. But because its thickness is variable, in engineering practice it is difficult to accurately determine the thickness. The sloping layer thickness depends on the requirements of the roof energy saving. It is important to thoroughly analyze the principle of roof heat transfer and to establish the mathematical model of roof heat transfer. Then through rigorous mathematical calculation, the common law of how to determine the sloping layer thickness can be summed up. According to the slope gradient, slope length and layer thickness calculation value, the maximum thickness and the minimum thickness can be ultimately determined.

The calculation methods on the base of the concentrated parameters models, which were formed in the XX century, allowed to get simple and theoretically consistent solutions for the problems of one-layered building partitions sound insulation finding. The sound insulation estimation for the double-layered massive building partitions also is of scientific and practical interest, as double layer partitions are the particular case of the single layer enclosure's application. The concept of concentrated parameters includes the concentrated and the reduced masses, as well as the concentrated elasticity. The criteria for the object application as a specified kind of the concentrated parameters in the acoustical problems is the presence or the absence of the oscillation movement in it. The three calculation models with the application of the concentrated (discreet) parameters that to define the sound insulation of the massive double layer enclosures are given. The equations for sound insulation computation for one layer partition are represented. They were derived on the base of momentum law and energy conservation formulas under the continuity of energy flow conditions at the interface of different media. The three main paths of sound propagation from the room with the air-borne noise to the isolated room are shown. The two frequency range are separated on the way of the direct sound propagation: at the first, the surface density of the one of two layers and the air elasticity in the inter-layer gap influence on isolation; at the second one, the predominant role belongs to the summarized insulation by the "Mass Action Law" of the two layers. The indirect way's insulation is taken in account through the additional sound insulation graph drawing. The compound insulation curve is defined by the ways, where the sound energy transmittance is maximal at the standard frequency spectrum. The method of sound insulation calculation for the double layer partitions on the base of the concentrated parameters model application is revealed. As an example, the calculation of a prefabricated double layer inter-flat wall in the panel building was performed.

Multiple target magnetron sputtering technique was employed for the deposition of (Cr,V)2AlC thin films, on the substrate of Si wafer at temperatures ranging from ambient to 840 K. The chemical composition and crystal structure of the deposited thin films were analyzed, surfaces as well the cross sections observed. The experimental results demonstrated that the temperature of the substrate does not affect the chemical composition of the deposited thin films. Deposition at room temperature or moderate elevated temperatures was found to result in amorphous films, whereas crystalline MAX phase thin films were obtained at high temperature. The transition of the substrate temperature was found to be around 743 K. The thin films deposited at temperatures below the transition showed the featureless flat surfaces. At high substrate temperatures, crystalline MAX thin films were formed. When deposited at temperatures near the transition, amorphous/nanocrystalline double layer thin films were deposited.

Measurement of beach heights in the intertidal zone has great importance for dynamic geomorphology research, coastal zone management, and the protection of ecological resources. Based on satellite images, the waterline method based on satellite images is one of the most effective methods for constructing digital elevation models (DEMs) for large-scale tidal flats. However, for fast-changing areas, such as Tiaozini in the Jiangsu coast, timely and detailed topographical data are difficult to obtain due to the insufficient images over a short period of time. In this study, as a supplement to the waterline method, an artificial neural network (ANN) model with the multi-layer feed-forward back propagation algorithm was developed to simulate the topography of variable Tiaozini tidal flats. The “7-15-15-1” double hidden layers with optimized training structures were confirmed via continuous training and comparisons. The input parameters included spectral bands (HJ-1 images B1~B4), geographical coordinates (X, Y), and the distance (D) to waterlines, and the output parameter was the elevation. The model training data were the HJ-1 image for 21 March 2014, and the corresponding topographic data obtained from the waterline method. Then, this ANN model was used to simulate synchronous DEMs corresponding to remote sensing images on 11 February 2012, and 11 July 2013, under low tide conditions. The height accuracy (root mean square error) of the two DEMs was about 0.3–0.4 m based on three transects of the in-situ measured data, and the horizontal accuracy was 30 m—the same as the spatial resolution of the HJ-1 image. Although its vertical accuracy is not very high, this ANN model can quickly provide the basic geomorphological framework for tidal flats based on only one image. This model, therefore, provides an effective way to monitor rapidly changing tidal flats.

Background The aim of this study is to present technical strategies to decrease donor-site complications, to optimize breast shaping, and to achieve symmetry in one-stage procedure in latissimus dorsi (LD) flap reconstruction. Methods Between 2004 and 2014, a retrospective review was performed on LD flap reconstructions. Demographics, reconstructive details, clinical and aesthetic outcomes were collected and analyzed. Patients were divided in historical control group (HCG) and new strategy group (NSG). In HCG, a horizontal/oblique LD skin paddle (SP) was drawn; only LD muscle was harvested for the implant pocket; and a contralateral symmetrization was planned without any algorithm. In NSG, a transverse LD-SP was centered on the middle to lower bra strap area; a double-layer muscle coverage was used to create the implant pocket; and a planning algorithm was developed to achieve symmetry. Results A total of 418 breast reconstructions were performed on 296 patients. The two groups were homogeneous regarding demographics, mastectomy weight, and implant volume (p > 0.05). No differences were observed in the incidence of a contralateral surgery, mean hospitalization time, and mastectomy skin flap and nipple–areola complex complications (p > 0.05), while surgical revision of the balancing procedure was more common in HCG than NSG (p = 0.001). Overall, donor-site morbidities occurred in 50 cases including 3 (1%) seroma in NSG and 17 (14.1%) in HCG, and 8 (2.7%) wound dehiscence in NSG and 18 (14.5%) in HCG (p = 0.001). Mean number of take backs to the operating room for secondary procedure was statistically significant between the groups in favor of NSG (p = 0.001). Conclusion Careful preoperative planning and adoption of appropriate reconstructive strategies can improve clinical and aesthetic outcomes in LD flap breast reconstruction at long-term follow-up. Level of Evidence This is a level III, therapeutic study.

Some crops have shown not to adapt to the no-tillage system (NTS) as a consequence of the compaction of the superficial soil layer. In a certain way, the mechanism used in seeders to open furrows for the deposition of fertilizers can have great importance in facilitating root penetration. This study was carried out to evaluate the influence of two fertilizer distribution mechanisms and N fertilization in upland rice (Oryza sativa) under NTS. The experiment was carried out in the growing seasons 2001/2002 and 2002/2003, in Botucatu, state of São Paulo, Brazil. A completely randomized block design was applied, with subdivided plots and four replications. Main plots consisted of two furrow opening mechanisms (furrow opener and double disk). Subplots consisted of four side dressing N levels (0, 40, 80 and 120 kg ha-1). The following parameters were evaluated: furrow and seed deposition depth, plant population, plant height, number of stems and panicles m-2, number of spikelets per panicle, spikelet fertility, weight of 1,000 grains, shoot dry matter, grain yield and N levels in the flag leaf. The success for upland rice establishment under the NTS in dry winter regions of Brazil is directly associated to the furrow opening mechanism of the seed-drill. The furrow opener mechanism resulted in deeper seed deposition, consequently decreasing seedling population, number of panicles per area and grain yield. Side dressing N fertilization in upland rice under NTS increases grain yield whenever the double disk mechanism is used to sow.

Background: Surgical resection of a large anterior skull base (ASB) tumor and sinonasal maglinancies with intracranial extension will result a large skull base defect. Reconstruction of large ASB defects by using traditional techniques may result in high risk of postoperative CSF leakage, meningitis and increase mortality rate. The use of pedicled double flap technique to reconstruct the anterior skull base defect may decrease the complications. In this study, we examine the clinical outcomes of patients who underwent this double flap reconstruction technique after the resection of sinonasal malignancies with significant intracranial extension at Cho Ray hospital, Vietnam. Methods: Case series study was conducted at Cho Ray hospital from 09/2010 to 09/2020. All patients with large sinonasal malignancies with intracranial invasion underwent combined transbasal - EEA approach. Reconstruction of large skull base defect ( > 2 cm ) was followed by using the pedicled double flap technique. Results: There were 75 patients who underwent the modified multi-layer with double flap reconstruction technique after the resection of ASB tumor from 09/2010 to 09/2020. The skull base defects were commonly seen at the horizontal plate of the ethmoid and the roof of the ethmoid ( 98.6%). The large skull base defects ( > 2cm) accounted for 81.3%. The risk of postoperative CSF leakage after double flap repair was very low. In this study, we had 1 patient with postoperative CSF leakage and 1 patient had postoperative meningitis. Conclusion: The use of two vascularize pedicled flap may decrease the incidence of postoperative cerebral spinal fluid (CSF) leakage and meningitis. This technique is an effective method for the reconstruction of the ASB with large defect.

AbstractWrinkling of thin sheets under strain is a universal phenomenon. The amplitude and period of the wrinkles formed in a thin sheet clamped at both ends are dependent on its strain and material parameters. In our study, wrinkling is observed in microscale for double clamped thin films (L>W>>t) consisting of 200nm deposited low stress silicon nitride bridges fabricated by bulk micromachining. A bilayer system is formed with 30nm aluminum evaporated on to these bridges. At room temperature the bridges are essentially flat. When an electrical current passes through the aluminum layer electrothermal, heating results in thermal expansion that wrinkles the bilayer. In addition we investigated various dimensions of the bridges and their correlation to the amplitude and the number of wrinkles. The observations are compared to existing wrinkling theory.

Diploma thesis on a topic ‘Municipal restaurant‘ deals with a new building proposal of a restaurant. An object is designed in the central part of a village called Štěměchy. It is a brick detached building in a slightly sloping terrain. The new building is a double-storeyed. The building has a letter ‘L‘ shape in the floor plan. The main entrance is situated from the south-east side. We can enter the restaurant from the wind lobby. The restaurant is connected with a bar and an outdoor terrace. There is a beverage store etc. next to the bar. A sanitary located background and a cleaning room are at the back side. There are accessible bowling lanes from this place. There are two entrances to the building from the north-east side. We can enter the outdoor equipment storage from the first door and the second one to the hallway which is served as for deliveries, an employee´s entrance and for taking the rubbish out from the waste repository of the kitchen. The hallway connects the restaurant to the kitchen which adheres to the rough vegetable preparation, a store with a freezer and some fridges, a dry store, a background for employees, an office, a cleaning room, an oil store, a mixed waste, a cooled waste and a utility room. There is an attic which is accessible from the wind lobby behind the main entrance. We can go to the hallway up the stairs. The hallway connects the area for exercise and an associated store of exercise aids to the roof terrace, the cleaning room and the sanitary facilities. The sanitary facilities is divided to the men´s part and women´s part. It is made by changing rooms, showers and toilets. The wall system is formed by ceramic blocks of Porotherm. There are a timber joist floor and a plank floor in the attic part. There is a system ceiling of Porotherm company where is placed a warm flat roof´s assembly with an extensive greenery . The attic part is roofed by the sloping gable double–layer roof which is made by a timber collar beam´s roof truss.

The aim of diploma’s thesis is a design od school house, exactly language school and english kindergarten. It’s a new building, designed on a flat plot no.873/21 in cadastre unit Horni Herspice, in a Brno’suburb. The language school is intended to accommodate 41 students. Kindergarten is for education preschool children. Kindergarten is designed for total capacity of 40 children. The building was designed in a rectangular shape without cellar. It is a two-storey masonry system. Both parts of the building were designed so that students and children do not meet. A schoolmaster office is located on the second floor. The building was designed from sand-lime bricks KM Beta. The thermal insulation is made from external thermal insulation composite systems ETICS, floor structure is from ceramic-concrete precast floor slabs. The major part of the flat roof structure is double-layered while the rest is a green single-layer construction.

The subject of this diploma thesis is the building design and project documentation of a new kindergarten in Brno. It is a new detached building structure with two floors, designed on a flat plot no. 1510/1 in cadastre unit Brno – Komín. The building is constructed of clay masonry with contact thermal insulation, supported by strip foundations. Ceiling construction is made of prestressed hollow-core slabs. This object is roofed by a single-layer and double-layered, flat roof. This kindergarten is designed for 60 children divided into three sections. Two sections are located on the 1st floor together with food preparation and technical rooms. The third section is on the 2nd floor with headquarters and a common room. This project was developed using AutoCAD software. The focus during development was on the proposed layout design in accordance with the kindergarten’s operations.

碩士
國立臺北科技大學
建築與都市設計研究所
92
The bad heat insulation performance of a building’s outer construction is the main cause for high temperature because of absorbing excess solar radiation heat, which reduces human comforts and increases air condition burden with more electricity consumption. Based on the assumption of natural power and sources in the environment, and assist with thinking of proper and effective integration to outer building construction, the research is designed to take outer roof construction of the building as study object. A double-layer to flat roof construction of the building is applied and buoyancy ventilation effect produced by the air-layer heat is explored to find out the possibility of increasing heat insulation. Through experimental devices, the research method aims to make substantial improvement and conduct a test of outdoor model, conducting combination modes before and after and diverse types respectively focusing on construction and building physics environment parameters (including temperature, wind velocity, humidity, heat and solar radiation strength etc.), records, arrangements, and understanding of its performances for carrying out the assessment of heat insulation. The experimental findings reveal that when the outer covering of the roof is of RC original construction, the performance of the heat insulation would perform poorly. However, the design in this research presents a double-layer ventilation roof of a flat roof, which indeed remove considerate degree of solar radiation heat absorbed on the roof surface because the buoyancy effect heatedly produced between the two new and old layers, which can contribute to increase heat insulation of the overall roof construction. In the daylight period, the heat conduction of an original RC roof can be lower to 11% of a naked roof. Meanwhile, in the period of maximum indoor air-conditioning load, the value is only 16% heat conduction of the naked roof. If we put the installation of natural ventilator and parapet into consideration, it can be found that in the performance of heat insulation of a building, it performs the best when there is a ventilator but no parapet. It performs the second when there is a ventilator and a parapet. On the other hand, it performs the worst when there is a parapet and no ventilator. Compared with the original design of double-layer ventilation roof, when natural ventilator is removed, and the percentage between the original RC roof and the naked roof, it increases 73% in the daylight period. Meanwhile, it is also on the increase of 25% in the period of maximum indoor air-conditioning load. If there is no parapet installed, the all heat currents change the direction (flow from interior room to outdoors), and the percentage in quantity respectively become 73% and 6% of the originally designed roof construction. In the designs of double-layer ventilation roof construction, measures are taken such natural ventilator installation and barriers cutting down air can be of much help in promoting heat insulation of an overall roof construction. The experiment is proven that double-layer ventilation roof construction of a flat roof representing in the research indeed has outstanding heat insulation. Under the situation that outer roof construction of the building today is commonly poor in performance. In consideration of limitation under the laws and regulations, application of roof platform and fire escape functions, this research has passed related construction design and testing process, providing a feasible energy-saving construction application as reference.

碩士
國立臺北科技大學
建築與都市設計研究所
94
There is no doubt that solar energy, which is clean and non-hazardous, could contribute considerably to a solution of the energy problem if appropriate method is developed to collect, concentrate, store and convert solar radiation which is diffuse and intrinsically intermittent. Especially in Taiwan, people suffer from the heat between May to October. During this period, solar radiation of horizontal plane is two to three times comparing with vertical ones. The heat causing by solar radiation results in interior space hardly achieving the requirement of comfort. This study develops a double-layer roof with a layer of air inside insulation interior space from heat to reduce energy consumption. Moreover, solar collector in the shape of net is embedded in the double-layer roof. The device, a concrete solar collector, collects in solar energy for heating water. The surface of roof, which directly contacts solar radiation, becomes a multi-function fabric of heat insulation and collector. It reduces the interior heat load and gaining the possibility of energy recycle. The study demonstrates a new idea of forming familiar materials and evaluates the performance by real case. It also conducts an analysis on the performance of double-layer roof and concrete solar collector. According to the result, it evidences that the proposed device actually benefits in heat insulation, reducing 36.93% to 84.64% of the coefficient of heat transmission comparing with single layer roof of RC. In addition, the proposed device also has good performance in heat collection. The experiment illustrates the temperature can be accepted for bath. Most roof design doesn’t take the function of heat insulation into consideration until now. Based on the limitation of registration on the roof and calamity prevention, the study provides a practical mechanism which integrating concrete and solar collectors from energy-saving perspective.