Compartment Walls Research Articles

Sintering-Resistant Nanoparticles in Wide-Mouthed Compartments for Sustained Catalytic Performance

Particle sintering is one of the most significant impediments to functional nanoparticles in many valuable applications especially catalysis. Herein, we report that sintering-resistant nanoparticle systems can be realized through a simple materials-design which maximizes the particle-to-particle traveling distance of neighbouring nanoparticles. As a demonstration, Pt nanoparticles were placed apart from each other in wide-mouthed compartments tailored on the surface of self-assembled silica nanosheets. These Pt nanoparticles retained their particle size after calcination at elevated temperatures because the compartment wall elongates the particle-to-particle traveling distance to preclude the possibility of sintering. Moreover, these Pt nanoparticles in wide-mouthed compartments were fully accessible to the environment and exhibited much higher catalytic activity for CO oxidation than the nanoparticles confined in the nanochannels of mesoporous silica. The proposed materials-design strategy is applicable not only to industrial catalysts operating in harsh conditions, but also opens up possibilities in developing advanced nanoparticle-based materials with sustained performance.

COLLAPSE AND FLEXURAL-TORSIONAL BUCKLING TEMPERATURES AT FIRE FOR BEAMS IN STEEL FRAMES

When a steel beam arranged in a steel frame is exposed to fire, compressive force, that is thermal stress, is generated in it with member temperature increase, because the liner thermal expansion is restricted by the adjacent members. It is, however, well known that the generated thermal stress is attenuated by plastic deformation occurred in the steel frame at elevated temperature, finally disappears when the heated beam exhibits collapse mode. The collapse temperature is independent of the thermal stress in case of stable plastic collapse mode. On the other hand, there is a possibility that the open cross-section beam unstiffened in the out-of-plane direction exhibits flexural-torsional buckling in the process of fire by acting the large compressive force. Since the flexural-torsional buckling resistance depends on the compressive force, it is considered that the member temperature at the flexural-torsional buckling depends on the thermal stress. The main purpose of this study is to clarify the flexural-torsional buckling behavior of the beam at the fire arranged in the steel frame and propose theoretical solutions on the flexural-torsional buckling temperature considering influence on the thermal stress. Three dimensional finite element analyses are conducted to verify the theoretical solutions. A line element being capable of analyzing the flexural-torsional behavior of the member is used. Both geometrical and material nonlinearity are considered in the numerical analysis. Three types of partial frame models including a fire compartment room are analyzed and their numerical flexural-torsional buckling and collapse temperatures are estimated, respectively. By comparison of the theoretical solution with the analytical results obtained by the parametric analyses, the following 1) and 2) were clarified. 1) The unstiffned beam at the fire exhibits the flexural-tosional buckling and the large buckling deformation in both in-plane and out-of-plane directions occurs with the temperature increase. The flexural-torsional buckling temperature becomes lower when the liner thermal expansion is strongly restricted by the adjacent members. However, the beam can sustain vertical loads after the buckling. The thermal stress is attenuated by the plastic deformation in both in-plane and out-of-plane directions generated in the buckled beam. The beam can resist up to the temperature when the thermal stress disappears. The collapse temperature is higher than the flexural-torsional buckling temperature, however, the plastic deformation in the out-of-plane direction is very large. 2) The flexural-torsional buckling temperature of the heated beam at the fire can be safely estimated by the theoretical solution proposed in this study. The collapse temperature of the beam after the buckling can be estimated by the theoretical collapse temperature based on the simple plastic theory. It is considered that fire resistance of the beam in the case when the plastic deformation in the out-of-plane direction cannot be allowed, for instance, in the case when the heated beam adjoins fire compartment walls, should be estimated by the theoretical flexural-torsional buckling temperature.

Earth pressures on modified suction caisson in saturated sand under monotonic lateral loading

A modified suction caisson (MSC) can be used to support the offshore wind turbine. This paper presents an experimental study and a numerical simulation on the earth pressure distribution along the MSC embedded in saturated marine fine sand. Results show that the yield envelops for the MSC and the corresponding regular suction caisson in the H-M space can be represented by a linear relationship. It was also found that the Prasad and Chari method, which is popular in analyzing the earth pressure distribution along lateral loaded rigid plies, can well predict the maximum net earth pressure on the regular suction caisson. However, for the MSC, since the external skirt can resist a considerable portion of the lateral load, Prasad and Chari method overestimates the maximum net earth pressures acting on the internal compartmental shaft of the MSC. Numerical simulation results indicate that in the ultimate limit state the maximum net earth pressure acting on the external skirt wall in the loading direction is larger than that on the internal compartment wall. However, the maximum net earth pressure along the caisson embedded depth is obtained at the MSC base opposite the loading direction. In addition, the separation between the top lids of the internal compartment and external skirt occurs opposite the loading direction. The lateral load and the resulting overturning moment acting on the MSC are mainly carried by the passive earth pressure zones along the inner and outer shafts of the internal compartment and the external skirt both in the loading and opposite the loading directions and under the external skirt lid in the loading direction. The main reason of the suction caisson failure is that the sand in the lower passive earth pressure zone opposite the loading direction yields completely.

Manufacture and properties of protective sound-absorbing mesh-reinforced composite foam board: Effects of filler content and mesh opening

In this article, the mesh fabric and porous filler are combined with polyurethane (PU) foam to fabricate sound-absorbing composite boards with puncture resistance and cushion protections, after which sound absorption and static puncture resistance are improved. Effects of fillers (vermiculites and perlites) content and mesh opening ratio on sound absorbing, puncture resisting and cushioning properties are explored respectively. Result shows that, mesh fabric improves the low-frequency coefficients, and also increases the puncture resistance by 2 times and 1.5 times for 2-mm-diameter and 4.5-mm-diameter probes penetrations. Absorption peak shifts to the lower frequency with increase of fillers content and mesh opening, but static puncture resistance against 4.5-mm-diameter probe decreases with mesh opening ratio. The fabricated composite foam boards can absorb 90 % of impact energy when compounding with 10 wt% vermiculite fillers and 45 % opening fabric, which shows the favorable cushioning protection. This mesh-reinforced composite foam boards can be applied as protective compartment walls whatever in gerocomium, women and children care center, kindergarten or karaoke TV room.

Thermoplastic polyurethanes/polyester/polypropylene composites: Effect of thermoplastic polyurethanes honeycomb structure on acoustic-absorbing and cushioning property

A new acoustic absorbing/cushioning composite is fabricated by thermoplastic polyurethanes honeycomb structure – thermoplastic polyurethane honeycomb cushion and grid, and composite nonwoven in this study. Composite nonwoven is composed of different layers of polyester/polypropylene nonwoven and polyester nonwoven. Research result shows that layer combination of polyester/polypropylene nonwoven and polypropylene nonwoven affects acoustic absorption and thermal conductivity of resulting composite nonwovens. The thermal conductivity of composite nonwovens decreases to 0.02213 W/(m K), showing excellent thermal-insulating property. Honeycomb structure–thermoplastic polyurethane honeycomb cushion and grid broadens the acoustic absorbed frequency and improves the mid- and high-frequency absorption coefficient and cushioning property of thermoplastic polyurethane/polyester/polypropylene composites. Incorporation of different honeycomb structure into composite nonwovens presents diversified acoustic-absorbing characteristic profiles. The resulting 35-mm-thick thermoplastic polyurethane/polyester/polypropylene composites absorb 85% acoustic waves at 1250 Hz and 94.2% at above 2000 Hz as well as 92.88–96.59% impact energy. Therefore, it becomes an excellent alternative for protective wall in kindergarten and gerocomium and compartment wall in the building.

공동주택 세대내 경량벽체 화재안전 성능기준 설정

최근 공동주택 구조형식이 벽식 구조에서 리모델링이 자유로운 기둥식 구조로 변화고 있으며, 이에 따라 경량벽체의 활용이 점차 늘어나고 있다. 공동주택에 사용이 증가하는 경량벽체는 소비자의 다양한 요구수준에 부합하여야 하나, 국내에서는 경량벽체에 대한 요구 성능별 성능기준이 미비한 실정이다. 경량벽체 화재안전성능도 국내 건축법에 따라 세대간 벽체의 성능기준만 규정되어 있는 상황에서 재실밀도가 높은 공동주택에 적합한 화재안전을 위하여 세대내 벽체로 사용되는 경량벽체의 화재안전성능을 3등급으로 제시하고 제시된 등급에 대하여 일반적으로 많이 적용되는 경량벽체 품목을 대상으로 화재안전성능을 평가하였다. Recently, the structure system for apartment buildings in Korea has been changing from wall to post-beam structure. This study examines the fire safety performance of light-weight dried wall, a component of post-beam structure. For the fire resistance in Korea, the Compartment wall of apartment house in the case of building regulation has regulations specify the detailed requirement of fire compartment walls in apartment, but do not specify that of interior finish walls. This study proposes the fire safety rate of the interior finish wall into three grades in which the highest grade requires fire resistance of 30 minutes.

The Rungus Longhouse of Sabah, Malaysian Borneo – A Dying Architecture

The Rungus tribal group can be found in the northeast corner of Sabah, Malaysian Borneo, farming the land mostly on agricultural products in small scale plantations. Their longhouses, facing extinction, are dual-purpose dwellings, constructed entirely of traditional materials utilising small split timbers lashed with rattan for the frame, palm fronds for the thatched roof, split bamboo for the floor and tree bark of hewn wood for the compartment walls. Each family has its own separate quarters off a common hall for socialising and community work. Village life is usually communal and the village is the major political unit based on the cultural traditions. Strongly related to the spirit of the place, the ‘rice spirit’, in particular, figures prominently in the Rungus people’s beliefs and practices in controlling the spirits and the people’s daily life. Unfortunately, all of these unique beliefs seem to have disappeared through time, thus requiring proper documentation of the longhouses. The objectives gear towards analysing the architectural values and investigating cultural understanding associated with the longhouses. Most importantly, the issue of how the Rungus people relate to the environment is studied through the tangible and intangible cultural aspects of the people. The research utilises the observation technique, interviews with the residents, visual data collection and measured drawings of five longhouses as the processes to document data. The paper instigates an investigation into the conformity of the Rungus people of their place in the environment to perpetuate their lifestyle in a land that is surrounded by nature.

Study on manufacturing of W-Cu alloy thin wall parts by selective laser melting

In order to achieve rapid manufacturing of tungsten-copper alloy part, copper alloy parts (CuW, CuSn, CuP, with mass ratio of 1:2:2) were manufactured by selective laser melting (SLM), and the influence of different energy input was investigated. The methodology of separating part model was adopted to overcome the manufacturing defects that was caused by the scanning strategy. The results shown that the thicknesses of the thin walls gained by SLM vary from 123 to 276 μm with the laser power varying from 100 to 120 W and the scanning speed of 200 to 700 mm/s. The compartment walls obtained through separating part model were of uniform thicknesses and nonclogging pores. It provides a feasible method for manufacturing precise parts containing tungsten and mass manufacturing of precise microcomponents by the SLM process.

화재시 비차열 유리의 복사열에 관한 실험적 연구

최근 국내에서는 건축물에서 공간의 미관이나 활용성 때문에 유리창 및 유리벽체의 사용에 대한 관심이 높아지고 있다. 하지만, 건축물의 내부공간은 화재시 연소확대 및 인명피해를 막기 위해 건축법에 따라 내화구조로 방화구획을 하여야 한다. 이러한 방화구획벽에 비차열 유리를 사용할 경우, 화재시 인접 거실로 복사열에 의한 화재의 확대, 인명 피해가 일어날 수 있다. 본 연구에서는 비차열 유리창에 대한 복사열의 위험성을 평가하기 위하여 내화실험을 실시하여 실험체 이면에서의 온도와 열류량을 측정하여 그 결과를 분석하였다. Recently in Korea, the interest for using window and window-wall in building picks up due to the beauty and utilization of space. But, interior space of the buildings shall be compartmentalized by fire resistance structures in accordance with the Korean building codes to prevent the spread of flame and damage of human life in fire. In case of installing non-insulated glazed window in compartment wall, the flame spread to adjacent space and the damage of human life by radiant heat can occur in fire. On this study, to confirm the risk of radiant heat for non-insulated glazed window in fire, the fire resistance tests were conducted. The temperature rise and heat flux on unexposed space was measured and analyzed.

공동주택 세대내 경량벽체 내화 및 차음 성능기준 설정

Recently, the structure system for apartment buildings in Korea has been changing from wall to post-beam structure. This study examines the fire resistance and sound insulation of light-weight dried wall, a component of post-beam structure. For the fire resistance and sound insulation in Korea, the Compartment wall of apartment house in the case of building regulation has regulations specify the detailed requirement of fire compartment walls in apartment, but do not specify that of interior walls. This study proposes the fire resisting rate of the interior wall into three grades in which the highest grade requires fire resistance of 30 minutes and also proposes the requirement of sound insulation performance into three grades in which the lowest grade requires 35dB.

Development, Use, and Accuracy of a Homogenized Fuel Region Model for Thermal Analysis of a Truck Package Under Normal and Fire Accident Conditions

In the current work, a geometrically-accurate two-dimensional model is developed of an isolated fuel assembly within isothermal compartment walls. Finite difference thermal simulations are performed to determine the cladding temperature for a range of compartment wall temperatures and assembly heat generation rates. The results for zero-heat-generation-rate are used to determine a temperature-dependent effective thermal conductivity of the fuel region. The effective volumetric specific heat of the region is determined from a lumped capacity model. These effective properties are then applied to a two-dimensional model of a legal weight truck cask with homogenized (smeared) fuel regions. Steady-state normal conditions of transport simulations are performed for a range of fuel heat generation rates. The generation rate that brings the zircaloy cladding to its radial-hydride formation temperature, predicted by the homogenized model, is greater than that determined by simulations that employ an accurate-geometry fuel region model. Transient regulator fire accident simulations are then performed for a range of fire durations. The critical fire duration is defined as the minimum that brings the fuel cladding to its burst-rupture temperature. That duration is found to decrease as the fuel heat generation rate increases. The critical durations predicted by the homogenized fuel-region model are shorter than those predicted by the accurate-geometry model.

The Architectural and Cultural Heritage of Sabah - The Rungus Longhouse

This paper dwells into heritage tourism that is related to the architectural and cultural heritage of the Rungus people of Sabah, Malaysian Borneo. It investigates the cultural influence on the architecture of the longhouse. The Rungus tribal group can be found in the northeast corner of Sabah, farming the land mostly on agricultural products in small scale plantations. Their longhouses, facing extinction, are dual-purpose dwellings, constructed entirely of traditional materials utilising small split timbers lashed with rattan for the frame, palm fronds for the thatched roof, split bamboo for the floor and tree bark of hewn wood for the compartment walls. Each family has its own separate quarters off a common hall for socialising and community work and village life is usually based on the cultural traditions. Strongly related to the spirit of the place, the 'rice spirit', in particular, figures prominently in the Rungus people's beliefs and practices in controlling the spirits and the people's daily life and often governed by the words of the bobohizans, the high priestess. The objectives gear towards analysing the architectural values and investigating cultural understanding associated with the longhouses. Most importantly, the issue of how the Rungus people relate to the environment is studied through the tangible and intangible cultural aspects of the people. The research utilises the observation technique, interviews with the residents, visual data collection and measured drawings of five longhouses as the processes to document data. The paper instigates an investigation into the conformity of the Rungus people of their place in the environment to perpetuate their lifestyle blessed with a unique heritage found in their architecture and culture, in a land where nature reigns. It is a heritage that worth a second look in the tourism industry of Sabah.

Energy balance in a confined fire compartment to assess the heat release rate of an electrical cabinet fire

Electrical cabinet fires are a major concern in nuclear power plants due to the significant impact on plant safety. This paper investigates electrical cabinet fires in highly confined and mechanically ventilated compartments. In particular, it addresses the issue of experimentally determining the heat release rate of an electrical cabinet fire through realistic large-scale testing. The fire source is highly complex in nature due to the heterogeneity, stochastic geometry and location of the combustible materials within the electrical cabinet.After providing a detailed description of the experiments and apparatus, this paper focuses on the thermal modeling necessary to assess the heat release rate based on the energy balance in the fire compartment, the ventilation system and the electrical cabinet itself. The experimental method is then applied to a propane gas burner and an analytical cabinet containing PMMA tiles with homogeneous spatial distribution in order to validate the thermal model and heat measurements. Finally, the method is used to assess the heat release rate and combustion efficiency of an electrical cabinet. The various terms of the energy balance are described in detail to show the major role of the thermal inertia of both the electrical cabinet and the compartment walls.

Toxicity and Relative Biological Effectiveness of Alpha Emitting Radioimmunoconjugates

Radioimmunotherapy based on α-particle emitters has excellent properties as a treatment against micrometastatic and disseminated cancers because of the short path length (50 - 80 μm) and high linear energy transfer (∼ 100 keV/ μm). Alpha-particles produce clustered DNA double-strand breaks and highly reactive hydroxyl radicals when hitting biological tissue. Hence, targeted α-particle therapy offers the potential of selective tumor cell killing with low damage to surrounding normal tissue. The ideal applications for targeted α-therapy are in treating neoplastic cells in circulation or when cancer cells are present as free-floating cells or spread along compartment walls. This review will provide a brief overview of the most promising radionuclides for targeted α-therapy and compare their relative biological effectiveness (RBE) and normal tissue toxicity.

Effects of Different Suppression Tactics on the Firefighter and Compartment Environment

Effects of Different Suppression Tactics on the Firefighter and Compartment Environment MATTHEW OBACH, ELIZABETH WECKMAN, and ALLAN STRONG Department of Mechanical and Mechatronics Engineering University of Waterloo 200 University Ave. W. Waterloo, ON, N2L 3G1 ABSTRACT Experiments are conducted to study the effects of different water-based indirect initial attack methods on the compartment environment and firefighter during compartment fire suppression. Hot layer temperatures typical of room fire conditions are developed in the test compartment using wood cribs. Five suppression methods including straight stream, penciling, continuous wide and narrow fog, and a wide angle burst method are examined for two different spray angles and nozzle pressures. Temperatures, heat flux, gas velocity, and gas concentrations are monitored throughout the fire compartment. Realistic, yet extreme, fire conditions are repeatedly established in the test compartment, allowing up to nine tests per fire. Differences in average compartment temperature before and during suppression indicate that penciling tactics provide little cooling of the compartment. In narrow fog attacks, the hot layer is pushed toward the floor, resulting in increased temperatures in the lower layer, generally an undesired result. Wide angle fog methods have greater impact on compartment temperature as compared to straight stream or narrow fog methods; however, they may also result in large increases in temperature at the firefighter. Wide angle burst tactics less effectively cool the compartment gases than continuous methods, but also lead to less impact on the firefighter. Greater numbers of bursts increase cooling of the compartment, but at the expense of increased impact on the firefighter. Including impact on the firefighter, continuous straight stream methods, at a nozzle pressure of 700 kPa and aimed to the top of the rear compartment wall, appear the best choice for initial attack on fires developed in these experiments. Due to variability between real fire scenarios and experiments such as these, significantly more study of the various suppression tactics is required before the most effective methods of suppression can be determined even for a given set of fire scenarios.

Wind effects on smoke motion and temperature of ventilation-controlled fire in a two-vent compartment

High-rise building fire is often influenced by the ambient wind. Study concerning fire behavior in the compartment of high-rise buildings in wind environment is needed for exploring some effective methods used for evaluation of compartment fire smoke movement and control. In this paper, smoke flowing direction and temperature of ventilation-controlled fire in a two-vent compartment are studied when ambient wind blows to the vent at higher altitude. It is found that there is a critical wind speed, above which the direction of smoke movement is dominated by wind rather than by buoyancy. It is also found that ambient wind has a complex influence on smoke temperature in the compartment. When wind speed exceeds another critical value, only one steady state appears in the smoke temperature rising curve. Otherwise three steady states appear. Heat transfer through the compartment walls has great influence on the second critical wind speed.

Bone marrow‐derived cells that home to acoustic deafened cochlea preserved their hematopoietic identity

The high degree of bone marrow cell (BMC) plasticity has prompted us to test its restoration possibility in inner ear repair. Our aim was to determine the potential of these cells to transdifferentiate into specialized cochlea cell types after acoustic injury and BMC mobilization. Lethally irradiated mice were transplanted with BMCs from green fluorescent protein (GFP) transgenic mice and subjected to acoustic deafening 3 months later. In a separate experiment, stem cell factor and granulocyte colony-stimulating factor were administered to test the effect of BMC mobilization on bone marrow-derived cell (BMDC) transdifferentiation. All mice showed almost complete chimerism 3 months after bone marrow transplantation. Upon acoustic trauma, robust BMDC migration was observed in the deafened cochlea. GFP+ cell migration was most prominent during the first week after acoustic deafening, and these cells accumulated significantly at the spiral ligament, perilymphatic compartment walls, and limbus regions. Most of the BMDCs expressed CD45 and CD68 and were identified as macrophages. Upregulation of stromal-derived factor 1 (SDF-1) was also observed in the spiral ligament during the first week after acoustic deafening. Cytokine treatment resulted in increased BMC mobilization in the systemic circulation. However, the presence of any stem cell progenitors or the differentiation of BMDCs into any cell types expressing cochlea sensory, supporting, fibrocytic, or neuronal markers were not detected in the deafened cochlea. In conclusion, we have demonstrated the homing capability of BMDCs to the deafened cochlea, and these cells displayed mature hematopoietic properties without spontaneous transdifferentiation to any cochlea cell types after acoustic trauma or bone marrow mobilization.

Effect of Computation Domain on Simulation of Small Compartment Fires

This paper presents a numerical exercise to investigate the effect of computation domain on simulation of compartment fires. Fire Dynamics Simulator was used to model steady state propane fires in a small compartment. The computation domain varied with its boundary set at the compartment wall containing an opening and extended beyond the wall at various distances. Simulations were conducted with different vent opening sizes and heat release rates. Both fuel controlled and ventilation controlled fire scenarios were investigated. The grid dependence and domain dependence were cross checked. It was demonstrated that there were significant differences in the predicted parameters between the domains with extensions and those without. Recommendations are provided on the basis of the current study for domain selection for the simulation of compartment fires.

Prediction of Fire Growth for Compartments of Office Buildings as Part of a Fire Risk/Cost Assessment Model

This article presents a zone model for the prediction of fire growth in a commercial compartment of an office building as part of a fire risk and cost assessment software package. The model developed is a combination of a transient, two-zone submodel used for the pre-flashover fire state and a quasi-steady, single-zone submodel for the post-flashover state. In the two-zone submodel, the selected four independent governing variables are pressure, enthalpy of the upper layer, and the masses of the upper and lower layers. To determine the conditions in the fire compartment, the model considers combustion, fluid flow, and heat transfer. The single-zone submodel includes the energy balance equation, and equations of energy losses due to smoke flow, conduction through the compartment walls, and radiation. The article also presents results of model validation using experimental data from tests in a standard room and in an experimental atrium with a smoke exhaust system. Comparisons of smoke, temperature, interfa...

Parametric analysis of the selective laser melting process

Selective laser sintering/melting (SLS/SLM) technology is used for manufacturing net-shaped objects from commercial Inox 904L powder with ≤20 μm particle size. Experiments were carried out on PHENIX-PM100 machine equipped with a 50 W cw fiber laser. Powder is layered by a roller over the surface of a 100 mm-diameter build cylinder. Optimal parameters of layer thickness and power input per unit speed for SLM were determined. It was shown that the greater the value of P/ V ratio is, the larger is the remelted line (called as “vector”). Influence of the shifting of consecutive single vectors on the process of forming the first layer was studied. Different strategies for forming objects with less than 1 mm-sized inner structures were tested, as, for example, forming a 20 mm × 20 mm × 5 mm box with 140 μm-thick inner compartment walls.