Hybrid Wall Research Articles

An Analytical Design Method for Steel-Concrete Hybrid Walls

The design of concrete walls or columns reinforced by several encased steel profiles, also called hybrid walls, is similar to the one of classical reinforced concrete, although specific features require adequate design approaches. Experimental research and numerical models demonstrated the feasibility and validity of such structural components, but simple and practical design methods are still lacking regarding their shear resistance. The evaluation of longitudinal shear action effects at the steel profile–concrete interface is a key aspect: research results have been achieved in a more or less recent past for different types of connection but without leading to design conclusions. In this paper, the classical equivalent truss model for reinforced concrete subjected to shear is extended to take into account the contribution of the encased profiles to the shear stiffness and strength. Resulting action effects in the steel profiles, in the concrete and at the steel profile–concrete interfaces are established which allows performing design checks for those three components. In particular, it is evidenced that friction is one of the main component of the resistance to longitudinal shear at the steel profile-concrete interface. It can be directly checked since the proposed method clearly identifies the compression stresses at that location. The validity of the method is assessed by referring to tests results from experimental campaigns in China and in Europe. Some of these tests were carried out without shear connectors welded to the encased steel profiles allowing however achieving the full bending resistance of the element without any apparent problem related to longitudinal shear, like slippage between concrete and steel profile. For some other tests, failure was observed as a consequence of an insufficient shear connection. A detailed assessment of these results shows that the new design proposal is perfectly consistent with all the experimental observations.

Numerical research of parameters of interaction of the gas flow with rotary valve of the gas pipeline

Conducted numerical research of static characteristics of the rotary gate valve at different angles of its deviation. for this purpose were set different values of pressure differential on the valve depending on which, was determined the mass flow and torque on valve axes. The mathematical model is provided by continuity equations, average on Reynolds, Navier-Stokes and energy, the equation of the perfect gas, the equations of two-layer k-e of model of turbulence. When calculating the current near walls are used Wolfstein's model and the hybrid wall functions of Reichardt for the speed and temperature. The task is solved in three-dimensional statement with use of conditions of symmetry. The structure of the current is analyzed: zones of acceleration and flow separation, whirlwinds, etc. Noted growth of hydraulic resistance of the valve with reduction of slope angle of the valve and with the increase in mass flow. Established increase of torque with reduction of the deviation angle of the valve and with increase in the mass expense.

Microencapsulation of porcine thyroid cell organoids within a polymer microcapsule construct

Hypothyroidism is a common condition of hormone deficiency, and oral administration of thyroid hormones is currently the only available treatment option. However, there are some disadvantages with this treatment modality including compliance challenges to patients. Therefore, a physiologically based alternative therapy for hypothyroidism with little or no side-effects is needed. In this study, we have developed a method for microencapsulating porcine thyroid cells as a thyroid hormone replacement approach. The hybrid wall of the polymer microcapsules permits thyroid hormone release while preventing immunoglobulin antibodies from entry. This strategy could potentially enable implantation of the microcapsule organoids containing allogeneic or xenogeneic thyroid cells to secret hormones over time without the need for immunosuppression of recipients. Porcine thyroid cells were isolated and encapsulated in alginate-poly-L-ornithine-alginate microcapsules using a microfluidic device. The porcine thyroid cells formed three-dimensional follicular spheres in the microcapsules with decent cell viability and proliferation. Thyroxine release from the encapsulated cells was higher than from unencapsulated cells ( P < 0.05) and was maintained during the entire duration of experiment (>28 days). These results suggest that the microencapsulated thyroid cell organoids may have the potential to be used for therapy and/or drug screening.

Hybrid System of Unbonded Post-Tensioned CLT Panels and Light-Frame Wood Shear Walls

Cross-laminated timber (CLT) is a relatively new type of massive timber system that has shown to possess excellent mechanical properties and structural behavior in building construction. When post-tensioned with high-strength tendons, CLT panels perform well under cyclic loadings because of two key characteristics: their rocking behavior and self-centering capacity. Although post-tensioned rocking CLT panels can carry heavy gravity loads, resist lateral loads, and self-center after a seismic event, they are heavy and form a pinched hysteresis, thereby limiting energy dissipation. Conversely, conventional light-frame wood shear walls (LiFS) provide a large amount of energy dissipation from fastener slip and, as their name implies, are lightweight, thereby reducing inertial forces during earthquakes. The combination of these different lateral behaviors can help improve the performance of buildings during strong ground shaking, but issues of deformation compatibility exist. This study presents the results of a numerical study to examine the behavior of post-tensioned CLT walls under cyclic loadings. A well-known 10-parameter model was applied to simulate the performance of a CLT-LiFS hybrid system. The post-tensioned CLT wall model was designed on the basis of a modified monolithic beam analogy that was originally developed for precast concrete-jointed ductile connections. Several tests on post-tensioned CLT panels and hybrid walls were implemented at the Large Scale Structural Lab at the University of Alabama to validate the numerical model, and the results showed very good agreement with the numerical model. Finally, incremental dynamic analysis on system level models was compared with conventional light-frame wood system models.

Testing and Modeling of Wood–Masonry Hybrid Wall Assembly

AbstractReinforced concrete or masonry cores commonly exist in multistory light wood frame buildings (LWFBs) as elevator shafts and stairwells. These cores are often not accounted for in structural design as part of the lateral load resisting system in combination with the light wood frame subsystem due to the uncertainty regarding material compatibility. In this paper, the interaction between the wood frame and masonry walls in a hybrid lateral load resisting wall system was investigated using a two-dimensional numerical model. Two two-story hybrid wood-masonry walls as well as individual wall subsystems and connections were tested experimentally under reversed cyclic loading to provide confidence in the ability of the numerical model to predict the lateral load response of the hybrid wall systems. From the experimental results it was noted that the bolted connections first failed when the load was applied to the wood frame in the hybrid system, while masonry walls first failed when the load was applied ...

Advanced near-wall modeling for engine heat transfer

Recent developments in the engine heat transfer modeling tend to improve existing wall heat transfer models (temperature wall functions) which mostly rely on the standard or low-Re variants of k-ε turbulence model. Presently applied mesh resolutions already allow for first near-wall computational cells reaching the buffer or locally even viscous/conductive sub-layer, thus increasing the importance of more sophisticated modeling approach. As temperature gradient-induced density and fluid property variations become significant, wall heat transfer is strongly influenced by property variations (viscous/conductive sub-layer) and predictive capability of the turbulence model (buffer region), standard wall laws being inadequate anymore, even for attached boundary layers. The present approach relies on the k-ζ-f turbulence model and formulates a compressible wall function of Han and Reitz in the framework of hybrid wall treatment. The model is validated against spark ignition (SI) engine heat transfer measurements. Predicted wall heat flux evolutions on the cylinder head exhibit very good agreement with the experimental data, being superior to similar numerical predictions available in the published literature.

Hybrid soil nail, tieback, and soldier pile wall – case history and numerical simulation

Excavations in congested urban areas are often carried out near and below the existing buildings. The primary cause of damages to nearby buildings is often associated with the excavation completed near and below the existing buildings. It is therefore imperative to minimise shoring wall displacement during the excavation. The paper describes the application of the hybrid soldier pile, tieback and soil nail shoring wall to reduce wall displacement below an acceptable limit. The project involved the construction of a 39-storey building with 5 levels of below-grade parking. The shoring of the below-grade parking was implemented with soil nails in the upper portion of the wall to prevent damages to the existing utilities. Tieback anchor was used below the existing building to limit the movements in the existing building. A three-dimensional non-linear analysis was used to study the behaviour of hybrid shoring wall. Field measurements on wall displacements and soil nail forces confirm the effect of the hybrid wall. However, numerical analyses indicated that the wall would have been constructed without soil nail due to a narrow space between the wall and existing building. This paper illustrates how detailed numerical simulation can be applied practically to design a shoring system in urban areas.

Experimental study on emulative hybrid precast concrete shear walls

The reversed cyclic lateral loading experiments were conducted on three, full scale, emulative hybrid precast concrete shear wall specimens with different post-tensioned forces and one reference monolithic RC shear wall specimen, and the measured results were then discussed in this paper. The emulative hybrid wall combined grouted vertical reinforcements with unbonded post-tensioned high-strength multi-strand tendons for lateral resistance, attempting to emulate the cast-in-place RC wall. Because of the presence of the unbonded post-tensioned tendon, by contrast to the monolithic wall specimen, the emulative hybrid wall specimens possessed higher strength, higher stiffness, and smaller residual displacement. The opening gap, resulted from the discontinuity of concrete and the locally debonding of vertical connecting reinforcements, was limited mainly due to the vertical connecting reinforcements across the joint distributed over total cross-section. Meanwhile, the emulative hybrid wall specimens were capable of providing energy dissipation and ductility capacity comparable to that of the monolithic specimen, and the negative effect of the post-tensioned force on energy dissipation was more obvious than on ductility. Moreover, the post-tensioned tendon remained elastic throughout the test and the yielding of the connecting reinforcements was delayed.

Utilizing the building envelope for power generation and conservation

Heat loading of the building envelope is caused by strong solar radiation and incorrect material selection. As a result of the heat loading of the building envelope, the indoor air temperature is increased, resulting in high energy consumption by air conditioners to maintain a comfortable indoor thermal environment. This study explores the use of a hybrid wall integrated with heat collectors (water piping system) and solar thermal power generators, which absorbs solar radiation through water to reduce heat transmission thereby saving energy and generating power. Power generation is achieved by an OD (oscillator device) that installed between a water tank (hot side) and building interior (cold side). The device acts by temperature differences between hot air (expansion) and cold air (contraction). CFD (computational dynamic simulation) was used to assess the effects of the hybrid wall on the interior environment. The results show that exterior heat is absorbed by cool water thereby reducing the heat transmission into the building, resulting in less energy consumption by air conditioners and power generation by use of temperature differences.

The performance evaluation of the modular design of hybrid wall with surface heating and cooling system

The performance evaluation of the modular design of hybrid wall with surface heating and cooling system

Designing an Automatic Control System for the Improved Functioning of a Solar Wall with Phase Change Material (PCM)

Solar walls constitute an important green architectural feature that positively contributes to energy saving in buildings. Different configurations may be proposed, such as, solar wall with Phase Change Material (PCM), composite solar wall, photovoltaic solar wall, zigzag solar wall, and solar hybrid wall. Being environmentally friendly, these passive solar components can provide thermal comfort and help save energy. Their disadvantages include principally unpredictable heat transfer, heat losses by night for some systems or inverse thermo-siphon phenomenon. Appropriate energy management techniques can be used to control and optimize the performances of solar walls. An experimental study for energy management of a PCM based solar wall is described in this paper. The experimental results show the effectiveness of the proposed automatic control system in regulating the capture of solar energy.

Experimental study of the chimney effect in a solar hybrid double wall

The solar hybrid-wall is widely used in natural ventilation and air heating in buildings. This article aims to experimentally study the induced chimney effect in a solar hybrid double wall. The effect of the air ventilation gap width and solar radiation intensity on the temperature distribution and induced air flow rate at the outlet of the hybrid wall was investigated with a variable chimney gap width-to-height ratio between 1:10 and 3:5. The results demonstrated that a lowest temperature position exists in the air gap and the position varies with the width of the air gap. The average air velocity in the air gap increases with the strength of the radiation intensity, and it shows a peak value with decreasing chimney gap width. The induced mass flow rate increases with both the radiation intensity and the chimney gap width. The optimum chimney gap width-to-height ratio is around 0.2–0.3 according to the coupling effect of the temperature and the air volume. Smoke visualization experiment demonstrates that reverse flow occurs in solar chimneys with a gap width-to-height ratio bigger than 0.3. It was found that the prediction method available in the literature can be well applied to narrow chimneys with a gap width-to-height ratio less than 0.3.

Integral wall model for large eddy simulations of wall-bounded turbulent flows

A new approach for wall modeling in Large-Eddy-Simulations (LES) is proposed and tested in various applications. To properly include near-wall physics while preserving the basic economy of equilibrium-type wall models, we adopt the classical integral method of von Karman and Pohlhausen (VKP). A velocity profile with various parameters is proposed as an alternative to numerical integration of the boundary layer equations in the near-wall zone. The profile contains a viscous or roughness sublayer and a logarithmic layer with an additional linear term that can account for inertial and pressure gradient effects. Similar to the VKP method, the assumed velocity profile coefficients are determined from appropriate matching conditions and physical constraints. The proposed integral wall-modeled LES (iWMLES) method is tested in the context of a pseudo-spectral code for fully developed channel flow with a dynamic Lagrangian subgrid model as well as in a finite-difference LES code including the immersed boundary method and the dynamic Vreman eddy-viscosity model. Test cases include a fully developed half-channel at various Reynolds numbers, a fully developed channel flow with unresolved roughness, a standard developing turbulent boundary layer flows over smooth plates at various Reynolds numbers, over plates with unresolved roughness, and a case with resolved roughness elements consisting of an array of wall-mounted cubes. The comparisons with data show that the proposed iWMLES method provides accurate predictions of near-wall velocity profiles in LES while, similarly to equilibrium wall models, its cost remains independent of Reynolds number and is thus significantly lower compared to existing zonal or hybrid wall models. A sample application to flow over a surface with truncated cones (representing idealized barnacle-like roughness elements) is also presented, which illustrates effects of subgrid scale roughness when combined with resolved roughness elements.

Construction of a virtual reality environment for robotic manufacturing cells

This paper describes the approach, algorithms, tools and implementation regarding construction from scratch of a simulation environment for robotic manufacturing cells following the virtual reality paradigm. A semantic model of robots ensures generality of the system, whereas fundamental robotics algorithms can be built into the environment, examples implemented concerning inverse kinematics for robotic arms with six rotary axes 6R, fast collision detection based on bounding boxes and interactive trajectory planning. The environment was developed in C++ making use of an open 3D graphics interface and a cross-platform user interface framework supporting different setups, i.e., enhanced desktop monitor, head-mounted display, glove and hybrid wall monitor, projector, game-type remote controller. Objects involved are virtual reality modelling language VRML versions of models originally designed in conventional 3D computer-aided design CAD systems. A sample application covering the design and training domains is demonstrated corresponding to selecting, positioning and programming a 6R robotic arm tending a turning centre.

ChemInform Abstract: Design and Synthesis of Organic—Inorganic Hybrid Capsules for Biotechnological Applications

AbstractReview: 50 refs.

Polyaniline Hybrid with Inverse Opal Structure for Fabrication of Thermoelectric Materials

The colloidal crystal template or opal with a closed-packed face centered cubic (fcc) lattice was prepared from monodisperse polystyrene (PS) microspheres by gravity sedimentation, and it was used for the fabrication of polyaniline hybrid with inverse opal structure. The template provided void space for the infiltration of Bi2Te3 and monomer that was then in situ polymerized to polyaniline. The opal composite was then soaked in toluene for completely removing PS microspheres to form porous polyaniline hybrid with inverse opal structure. The PS microspheres were replaced by air microspheres, which interconnected each other through the windows on the polyaniline hybrid wall. Both the wall and the air void constitute continuous phases. The polyaniline hybrid with inverse opal structure was observed with scanning electronic microscopy.

Damage assessment and performance-based seismic design of timber-steel hybrid shear wall systems

This paper presents a reliability-based analysis on seismic performance of timber-steel hybrid shear wall systems. Such system is composed of steel moment resisting frame and infill wood frame shear wall. The performance criteria of the hybrid system with respect to different seismic hazard levels were determined through a damage assessment process, and the effectiveness of the infill wood shear walls on improving the seismic performance of the hybrid systems was evaluated. Performance curves were obtained by considering different target non-exceedance probabilities, and design charts were further established as a function of seismic weight. Wall drift responses and shear forces in wood-steel bolted connections were used as performance criteria in establishing the performance curves to illustrate the proposed design procedure. It was found that the presence of the infill wood shear walls significantly reduced the non-performance probabilities of the hybrid wall systems. This study provides performance-based seismic evaluations on the timber-steel hybrid shear walls in support of future applications of such hybrid systems in multi-story buildings.

Design and synthesis of organic-inorganic hybrid capsules for biotechnological applications.

Organic-inorganic hybrid capsules, which typically possess a hollow lumen and a hybrid wall, have emerged as a novel and promising class of hybrid materials and have attracted enormous attention. In comparison to polymeric capsules or inorganic capsules, the hybrid capsules combine the intrinsic physical/chemical properties of the organic and inorganic moieties, acquire more degrees of freedom to manipulate multiple interactions, create hierarchical structures and integrate multiple functionalities. Thus, the hybrid capsules exhibit superior mechanical strength (vs. polymeric capsules) and diverse functionalities (vs. inorganic capsules), which may give new opportunities to produce high-performance materials. Much effort has been devoted to exploring innovative and effective methods for the synthesis of hybrid capsules that exhibit desirable performance in target applications. This tutorial review firstly presents a brief description of the capsular structure and hybrid materials in nature, then classifies the hybrid capsules into molecule-hybrid capsules and nano-hybrid capsules based upon the size of the organic and inorganic moieties in the capsule wall, followed by a detailed discussion of the design and synthesis of the hybrid capsules. For each kind of hybrid capsule, the state-of-the-art synthesis methods are described in detail and a critical comment is embedded. The applications of these hybrid capsules in biotechnological areas (biocatalysis, drug delivery, etc.) have also been summarized. Hopefully, this review will offer a perspective and guidelines for the future research and development of hybrid capsules.

Optimization of signal-to-noise ratio for wireless light-emitting diode communication in modern lighting layouts

White light-emitting diodes (LEDs) are predicted to be widely used in domestic applications in the future, because they are becoming widespread in commercial lighting applications. The ability of LEDs to be modulated at high speeds offers the possibility of using them as sources for communication instead of illu- mination. The growing interest in using these devices for both illumination and communication requires attention to combine this technology with modern lighting layouts. A dual-function system is applied to three models of modern lighting layouts: the hybrid corner lighting layout (HCLL), the hybrid wall lighting layout (HWLL), and the hybrid edge lighting layout (HELL). Based on the analysis, the relationship between the space adversity and the signal-to-noise ratio (SNR) performance is demonstrated for each model. The key factor that affects the SNR performance of visible light communication is the reliance on the design parameter that is related to the number and position of LED lights. The model of HWLL is chosen as the best layout, since 61% of the office area is considered as an excellent communication area and the difference between the area classi- fication, Δp, is 22%. Thus, this system is applicable to modern lighting layouts. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original

HYBRID SHEARWALL SYSTEM — SHEAR STRENGTH AT THE INTERFACE CONNECTION

Based on a series of alternating, displacement-controlled load tests on ten one-third scale models, to study the behaviour of the interface of a hybrid shear wall system, it was proved that the concept of hybrid construction in earthquake prone regions is feasible. The hybrid shear-wall system consists of typical reinforced concrete shear walls with composite edge members or flanges. Ten different anchorage bar arrangements were developed and tested to evaluate the column-shearwall interface behaviour under cyclic shear forces acting along the interface between column and wall panel. Finite element models of the test specimens were developed that were capable of capturing the integrated concrete and reinforcing steel behaviour in the wall panels. Special models were developed to capture the interface behaviour between the edge columns and the shear wall. A comparison between the experimental results and the numerical results shows excellent agreement, and clearly supports the validity of the model developed for predicting the non-linear response of the hybrid wall system under various load conditions.