Board Thickness Research Articles

Fire resistance of structural wooden walls covered by gypsum and diatomite board

The fire resistance of structural wooden walls covered with fire-resisting boards was investigated. A 49-mm-thick gypsum board (No. 1 and No. 2), a 24-mm-thick diatomite (No. 3), and a combination of gypsum and diatomite board (No. 4 and No. 5) were theoretically designed for 2-h fire resistance. As a result, when the gypsum board was fixed to the wood studs with nails (No. 1), there was no damage after 2 h, as predicted. When diatomite boards were used on the surface to face the fire (No. 3 and No. 4), the diatomite boards were destroyed after approximately 50 min because of the cracks of the diatomite board. However, when the diatomite board (6 mm) was placed inside the gypsum board (30 mm), the specimen (No. 5) showed a fire resistance of more than 2 h. Therefore, it is possible to reduce the thickness of the gypsum board using the diatomite board by avoiding placement of the diatomite board in direct contact with heat.

Experimental and Finite Element Study on Bending Performance of Glulam-Concrete Composite Beam Reinforced with Timber Board.

In this research, experimental research and finite element modelling of glulam-concrete composite (GCC) beams were undertaken to study the flexural properties of composite beams containing timber board interlayers. The experimental results demonstrated that the failure mechanism of the GCC beam was the combination of bend and tensile failure of the glulam beam. The three-dimensional non linear finite element model was confirmed by comparing the load-deflection curve and load-interface slip curve with the experimental results. Parametric analyses were completed to explore the impacts of the glulam beam height, shear connector spacing, timber board interlayer thickness and concrete slab thickness on the flexural properties of composite beams. The numerical outcomes revealed that with an increase of glulam beam height, the bending bearing capacity and flexural stiffness of the composite beams were significantly improved. The timber boards were placed on top of the glulam members and used as the formwork for concrete slab casting. In addition, the flexural properties of composite beams were improved with the increase of the timber board thickness. With the elevation of the shear connector spacing, the ultimate bearing capacity and bending stiffness of composite beams were decreased. The bending bearing capacity and flexural rigidity of the GCC beams were ameliorated with the increase of concrete slab thickness.

The Danube Strategy is Still Young

The paper draws lessons after 10 years of implementation of the EU Strategy for the Danube Region (EUSDR) from the perspective of a national coordinator in Austria. Starting by highlighting the double-nature origin of macro-regional strategies – being both an instrument for both foreign relations and development policies – it elaborates on a few selected value-added dimensions of the macro-regional approach and consequently concludes that the EUSDR’s work has contributed to translating major EU strategic notions into concrete implementation activities in the region, has triggered flagship-type projects and initiatives which go beyond the typical EU-funded project logic, has been stimulating new types of inclusive partnership approaches in the regions by opening up to civil society and, last but not least, has also helped to stabilise transnational cooperation governance among Danube countries in times of crisis. Forward-looking, the article concludes that macro-regional cooperation is like drilling thick boards and requires a long breath. Thus, 10 years of the EUSDR can only be regarded the start of a longer-term process.

Evaluation of durability performance of rice husk - cement bonded particleboards

Alternative resources as substitute for wood raw materials has increased in the particleboard industry because of the depletion of forest resources. Studies of particleboard using wood residues and agricultural by-products have examined wheat straw, rice straws, husks, bagasse, walnut/almond shells, and palm trunks. Rice husk is the by-product in rice milling operation with an approximately 20 percent of the total weight of the paddy grain being processed. Despite the abundant nature of this waste product and its unique physical and chemical properties, it is not being fully harnessed in Nigeria. Only a little portion of the rice husk produced is utilized in a meaningful way, the remainder is burnt into ashes or dumped as a solid waste with little being used in animal feed formulation.
 Particle board was produced from rice husk, an agro-waste and cement as binder. Physical and mechanical properties of the board were determined. The results show that, the percentage of thickness swelling and water absorption increased with increase in proportion of the binder to the rice husk. The Modulus of elasticity (MOE) values increase with increased mixing ratio for both the board thickness, while MOR values decrease with increase in mixing ratio for both particle sizes. Since the construction industry is a growing one, the use of renewable resources such as rice husk can reduce the strain on forest resource and form an excellent replacement for wood and wood based composite materials.

Fire Resistance of an Assembled Integrated Enclosure Panel System

Due to increasing economic development in recent years, large-scale prefabricated structures have been used for substations. However, the assembly of steel structures suffers from technical problems, such as the mismatch between the fire protection level of the main structure and the enclosure system. This paper proposes an assembled integrated enclosure panel system for covering and fireproofing steel structures, such as beams and columns, consisting of sandwich wall panels and autoclaved lightweight concrete (ALC) wall panels covering the main steel structure. Fire resistance tests were carried out for each part and the entire integrated enclosure panel system to fully investigate its fire resistance performance. ALC and gypsum were selected as the external fire protection materials for the sandwich wall panel test for theoretical analysis and fire resistance test. The fire resistance test results show that the designed solutions of sandwich wall panels and ALC panels covering steel beams and columns meet the fire protection requirements of the ISO-834 standard fire test. The proposed size scheme of the integrated enclosure panel system is an integrated sandwich wall panel composed of 50 mm thick ALC board + 50 mm thick rock wool layer + 50 mm thick ALC board and the integrated structure of 100 mm thick ALC board covering beams and columns. The designed U-shaped connectors between the wall panels are suitable for the assembled integrated enclosure panel system.

Experimental investigation on performance degradation of insulation materials induced by freeze–thaw cycles and its applications

• The degradation of XPS board induced by FTCs is analyzed and discussed in details. • The quantitative relationships between the numbers of FTCs and the performance degradation of XPS board are established. • The optimal thickness of XPS board by different laying methods is proposed by numerical simulation. XPS board as a good insulator is extensively used in construction and engineering to reduce heat loss. Unfortunately, the performance degradation of XPS board caused by freeze- thaw cycles (FTCs) was poorly studied. In view of this, a series of experiments were carried out in the laboratory. The compressive strength, thermal conductivity and volumetric water absorption of XPS board subjected to hundreds of FTCs are measured. Afterward, the optimal laying method of XPS board is proposed using numerical simulation method by taking a high-speed railway tunnel as a background. The results show that the compressive strength of XPS board is significantly affected by the thickness and numbers of FTCs. The maximum reduction rate of compressive strength caused by FTCs can reach 33 %. Additionally, the thermal conductivity and volumetric water absorption increase linearly with the number of FTCs. The thermal conductivity is always changed between 0.0329 W/(m·°C) to 0.0481 W/(m·°C). Based on that, the XPS board still has a good adiabatic performance after hundreds of FTCs. Besides, when the XPS board is laid in tunnel structural layer by surface method (SM) and interlayer method (IM) with the thickness of 6.5 cm, it can effectively prevent the surrounding rocks from freezing. In order to avoid frost heave of the secondary lining, the thickness of XPS board should be greater than 8.5 cm when the IM is selected. This study can provide some guidelines for the application of XPS board in constructions and engineering, especially for the cold regional tunnels.

High-toughness M-S-H cement composites reinforced with cellulose fibers through CO2 curing

This work evaluates the influence of a CO2-saturated curing environment on thin (5 mm thick) boards of magnesium silicate hydrated (M-S-H) cement composites reinforced with cellulose fibers (CF). The first stage of the work consists of the optimization of the curing temperature when samples are subjected to high CO2 curing conditions. By means of XRD, the optimal carbonation temperature was set at 45 °C, at which a higher peak intensity attributed to nesquehonite (MgCO3·3H2O) was reached. At the selected temperature, the carbonation reaction was assessed by TGA. Carbonation conditions promoted the formation not only of hydrated magnesium hydroxicarbonates (HMHC) crystals, but also of other poorly crystallized compounds. As a consequence, carbonation increased the total amount of hydrated phases present in the matrix. Mercury intrusion porosimetry (MIP) tests were performed in order to evaluate a modification of the pore structure after carbonation. In this regard, carbonation reduced total cumulative intrusion by up to 38%. Finally, bending tests revealed that carbonation increases the strength of the composites while preserving their high. This results also into unprecedented toughness values (8.78 kJ/m2) considering only the deflection up to the modulus of rupture (0.17%). Therefore, carbonation is presented as a curing technique able to leverage the potential of CF in fiber reinforced cementitious composites (FRCC).

Review of the NRC Canada Studies on Fire Resistance of Walls: Results, Research Gaps and Design Guidelines

The National research council Canada conducted three major fire resistance studies on the interior party walls, interior fire separation walls and exterior walls. The fire resistance results of these studies were published over the past three decades and the publications were short in suggesting design guidelines for practioners’ use and gaps for future research. This paper summaries the fire resistance results of 35 full-scale wall tests, suggests design guidelines and identifies future research gaps for interior party walls, interior fire separation walls and exterior walls. The result summary includes the effect of different design parameters on the fire resistance performance of wall assemblies such as the stud type and spacing, number of stud rows, number of gypsum board layers and thickness, mid-height blocking, resilient channels installation and spacing, screws spacing for attaching gypsum board to either wall faming or resilient channels, insulation type and exterior wall sheathing type on the fire resistance of loadbearing and non-loadbearing wall assemblies. The summary results was used as the basis for suggesting design guidelines for practioners’ use and identifying gaps for future research to improve the fire resistance performance of wall assemblies. For example, the use of a reduced screw spacing from 406 mm o.c. to 203 mm o.c. in the gypsum board field and from 406 mm o.c. to 150 mm o.c. at the board joints was suggested for future research to keep the protective gypsum board layer attached to studs or resilient channels longer for a better fire resistance performance of wall assemblies. Also, fire resistance design guidelines are suggested, for examples, the use of rock fibre insulation for non-load bearing interior party walls to achieve 1.5-h fire resistance, the use of cellulose fibre insulation for loadbearing fire separation walls to achieve 2-h fire resistance rating and the use of reduced screw spacing in attaching the gypsum board to wall framing from 406 mm o.c. to 203 mm o.c. for loadbearing exterior wall assembly with gypsum board glass mat sheathing to expand the fire resistance rating from non-useful 30-min to a useful code compliance 45-min fire resistance rating assembly. Additional suggested examples for future research gaps and design guidelines are also provided.

Effect of Stiffening the Printed Circuit Board in the Fatigue Life of the Solder Joint.

Predictive analysis of the life of an electronic package requires a sequence of processes involving: (i) development of a finite element (FE) model, (ii) correlation of the FE model using experimental data, and (iii) development of a local model using the correlated FE model. The life of the critical components is obtained from the local model and is usually compared to the experimental results. Although the specifics of such analyses are available in the literature, a comparison among them and against the same electronic package with different user printed circuit board (PCB) thicknesses does not exist. This study addresses the issues raised during the design phase/life analysis, by considering a particular package with a variable geometric thickness of the user PCB. In this paper, the effect of stiffening the user PCB on the fatigue life of a ball grid array (BGA), SAC305 solder joint is studied. The board stiffness was varied by changing the thickness of the PCB, while the size of the substrate, chips, and solder balls were kept constant. The test vehicle consisted of BGA chips soldered to a user PCB. The thickness of the user PCB was varied, but the surface area of the BGA chip remained identical. The test vehicle was then modeled using a finite element analysis tool (ANSYS). Using a global/local modeling approach, the modal parameters in the simulations were correlated with experimental data. The first resonance frequency dwell test was carried out in ANSYS, and the high-cycle fatigue life was estimated using the stress-life approach. Following the simulation, the test vehicle was subjected to resonance fatigue testing by exciting at the first mode resonance frequency, the mode with the most severe solder joint failure. The resistance of the solder joint during the experiment was monitored using a daisy-chain circuit, and the point of failure was further confirmed using the destructive evaluation technique. Both the experimental and simulation results showed that stiffening the board will significantly increase the fatigue life of the solder joint. Although the amplitude of the acceleration response of the test vehicle will be higher due to board stiffening, the increase in natural frequencies will significantly reduce the amplitude of relative displacement between the PCB and the substrate.

Application of Direct Stiffness-Strength Method for Design of Gypsum and Plywood sheathed CFS wall panels Subjected to Bending

The cold-formed steel (CFS) wall frames need to be stiff-strong to inhibit the instability failures. The current design specifications do not have a robust design method for sheathed CFS wall panels. A safe wall frame design is possible by providing adequate bracing to resist the instability failures, which the sheathing boards can do. A new design method based on the demand and supply approach called “Direct Stiffness-Strength Method” (DSSM) is developed to fulfill sheathing-bracing design needs. Nevertheless, it is necessary to validate the suitability of the DSSM for the design of CFS wall frames with various sheathing materials. In this study, a total of 58 CFS sheathed panels were tested under out-of-plane loading with varying design parameters such as global (λe), local (λl), and distortional slenderness (λd), two sheathing board types (Gypsum and Plywood), sheathing board thicknesses (tb), and sheathing fastener connection spacing (df). The full-scale test results indicate that the resistance of the sheathing fastener connection is sensitive to the thickness of the fibrous sheathing board plywood. The full-scale test results were compared with the design strength of CFS wall panels using DSSM. The sheathed CFS wall panel design indicates that the current DSSM method is unconservative for gypsum sheathing (both 12.5 mm 15 mm thicknesses) and overly safe for 12 mm thick plywood sheathing. This can be attributed to the omission of sheathing thickness in the DSSM approach to determine the stiffness and strength of the sheathing fastener connection. Further, the reasons for the inaccurate prediction of the current DSSM method are discussed in detail. A set of new resistance factor values are proposed for the accurate design prediction of sheathed CFS wall panels. Finally, the paper presents and discusses the application of the proposed design approach and provides evidence for the benefits of DSSM.

Structure and Materials of Urban Construction for Earthquakes and Fire Disasters Prevention

As urbanization becomes a significant factor in modern society, the security of urban constructions are very essential. This study focuses on the safety performance when urban constructions face disasters, especially earthquakes and fires, and analyzed the different structure and material methods. The results show the “chicken wire mesh” system could effectively protect the infilled structure from collapsing during an earthquake in a structural way. Furthermore, changing the ingredient or adding the admixture of concrete can also provide better anti-seismic ability with construction. In the field of fire resistance, thick timber board and ceramic concrete can effectively improve the fire-resistance ability of buildings.

Experimental Study on the Flexural Performance of Timber–Steel Composite (TSC) I-Beams

To promote the development of timber–steel composite (TSC) structures, this paper proposes a TSC I-beam with an I-beam as the webs, covered with a timber board on its upper and lower surfaces and bolted together; the effect of varying the ratio of the timber board thickness to I-beam on the bending performance of the TSC I-beam was investigated. Considering the same total height of the beam cross-section and the variation of timber board thickness and I-beam height, three groups of six TSC beam specimens were designed and fabricated to carry out bending load failure tests, and the effects of the variation of timber board thickness with respect to I-beam height on the failure mode, flexural load capacity, ductility, and composite degree of TSC beams were analyzed. In addition, a model for predicting the elastic ultimate bending capacity and mid-span deflection of TSC I-beams was proposed on the basis of the composite coefficient method, which avoids the need to test the joints, and the theoretical calculation results were in good agreement with the test results, which can provide a reference for the design of TSC I-beams.

RECIRCULATING AQUAPONIC SYSTEM ON DWC TYPE FLOATABLE SUPPORT AT ICDIMPH – HORTING

A recirculating aquaponic system on DWC type floatable support was carried out during the research activities carried out at ICDIMPH-Horting Bucharest in the period 2017-2021. It works on the principle of communicating vessels and satisfies the technological needs of fish and plant breeding. The system was placed in a micro-greenhouse made of polyethylene foil, according to a plan for the location of technological equipment, by reconditioning and arranging tunnels for growing of grafted plants. The construction included tunnels with a length of 7.40 m and a width of 1.81 m (fish growth tunnel, 70 cm high, made of 20 mm thick OSB boards, mesh and durable foil, 8 rectangular basins, with holes for aeration, water supply and drainage and inside two layers of ultra-additive foil, 0.2 mm thick and and tunnels for growing plant material), reconditioned by mounting a protective foil, attached in PVC clips to the skeleton of the tunnel and the base of the pools with an inclined slope of 5-10% for draining water and residues), installations, pumps, filters. It has been tested for growing carp (Cyprinus carpio) and lettuce (Lactuca sativa). Fish waste have been food for plants, and plants have naturally filtered water for fish, phytosanitary treatments with synthetic substances have been eliminated, lettuce obtained has had from quality categories I and II, the fish has had hematological parameters in the reference ranges indicated in the speciality literature for carp.

Studies on Water Absorption Properties of Fiber- Board Prepared Using Sugarcane Bagasse with Natural Resins

A study was conducted to evaluate the effect of fiber content and incorporation of natural resin on the water absorption behavior and swelling in thickness of sugarcane bagasse (SB)-reinforced epoxy-natural resin fiber-boards. Artificial (epoxy) and natural resins (cashew nut shell liquid (CNSL) resins, black dammar and pine resins) were used as a binder. The weight proportions of fiber: epoxy + hardener: natural resin were viz., 1:1:1.50, 1:1:1.75, 1:1:2. The lowest water absorption percent value for the sample immersed for 2 h and 24 h is shown by board prepared by mixing cashew nut shell liquid resin. There was less swelling in the thickness of the fiber board made with the fiber to resin weight ratio of 1:2.75. The cashew nut shell liquid resin was found to be effective in terms of Water absorption (WA) and thickness swelling (TS). Hence, the cashew nut shell liquid resin would be an alternate source for artificial resin source with less environmental hazards.

Calibration and application of high-frequency submersible sub-bottom profiler for deep-sea surficial sediment measurement

We developed a high-frequency submersible sub-bottom profiler (HF-SSBP) instrument for taking deep-sea sediment measurement. In order to evaluate the reliability of profile data, a laboratory calibration method (LCM) was developed using illuminated acrylic standard boards in anechoic tank to form multi-layer reflections and evaluate the errors of the HF-SSBP. Two layer reflections induced by single boards in different thicknesses and ranges were performed and recorded, after which four layer reflections induced by two boards with an adjusted water crack were set and logged. The results showed that the HF-SSBP resolution was 44.9 mm in acrylic and its equivalent in the sediment was 28.5 mm. The absolute measure error was 7 mm with an acrylic board thickness of 100 mm, and the maximum measure error was 3.5 mm in different water thicknesses. As a test and application, deep-sea sediment measurement of the HF-SSBP was launched and compared with in situ sampling cores in the same site. The measurement thickness for sections A and B are 39.4 cm and 23.2 cm, respectively, corresponding to the sampling core of 39.8 cm and 23.7 cm. The two results are close as we expected. This work demonstrates the reliability and accuracy of the HF-SSBP measurement, thus providing a good choice for deep-sea submergence vehicles to carry this sonar instrument to obtain high-resolution stratum in deep-sea surficial sediments.

Parametric Modeling and Characterization of Leakage-Integrated Planar Transformer for CLLC DC–DC Converter

With an objective to accurately characterize the leakage inductances and winding resistances of a high-frequency planar transformer (HFPT) for a 500 kHz resonant <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">CLLC</i> converter, this article elucidates the correlation between various specifications involved in hardware fabrication of various winding configurations and their structural dependence on the resultant parameters. A precise analytical model is developed using 3-D finite element analysis (FEA) to synthesize the effective magnetic field and current density distribution in fabricated winding structures. Furthermore, a thorough analysis to study the interdependence of the resultant parameters on specifications such as printed circuit board (PCB) thickness and its fabrication layout, air gaps, and conductor thickness is presented for various winding configurations, thus elucidating various design-based tradeoffs. Also, frequency dependence of the obtained parameters is described which validates the optimal selection of winding configuration based on the effective gain magnitude for the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">CLLC</i> converter topology. Detailed comparison between the developed analytical model with simulation model developed in Maxwell3-D and fabricated winding structures is presented, and the results validate the model accuracy, portraying an average mismatch of 3.8% and 6.2%, respectively.

Experimental Study of the Influence of Selected Factors on the Particle Board Ignition by Radiant Heat Flux.

Particleboards are used in the manufacturing of furniture and are often part of the interior of buildings. In the event of a fire, particleboards are a substantial part of the fuel in many building fires. The aim of the article is to monitor the effect of radiant heat on the surface of particle board according to the modified procedure ISO 5657: 1997. The significance of the influence of heat flux density and particle board properties on its thermal resistance (time to ignition) was monitored. Experimental samples were used particle board without surface treatment, with thicknesses of 12, 15, and 18 mm. The samples were exposed to a heat flux from 40 to 50 kW·m−2. The experimental results are the initiation characteristics such as of the ignition temperature and the weight loss. The determined factors influencing the time to ignition and weight loss were the thickness and density of the plate material, the density of the radiant heat flux and the distance of the particle board from the radiant source (20, 40, and 60 mm). The obtained results show a significant dependence of the time to ignition on the thickness of the sample and on the heat flux density. The weight loss is significantly dependent on the thickness of the particle board. Monitoring the influence of time to ignition from sample distance confirmed a statistically significant dependence. As the distance of the sample from the source increased, the time to ignition decreased linearly. As the distance of the sample from the source increased, the time to ignition increased.

Effect of electromagnetic induction coil position on feeding effect in steel ingot

The relationship between the feeding ability of the riser and the shrinkage and porosity is always a hot investigation topic, and the interior shrinkage and porosity of the ingot is the common defect met by industries. The work on the effect of Electromagnetic Feeding Riser (EFR) on ingot solidification is approached via the interpretative of the electromagnetic heat efficiency, temperature field, and Niyama criteria. The results show that the heating effect is better when the induction coil is at L = 0 mm and the heat efficiency rapidly reduces with the induction coil away from the riser, from the view of magnetic field. An obvious improvement in the solidification process is the application of EFR from the view of temperature field. Then, the Niyama criterion was defined as 1.1 through the experiment and simulation. Electromagnetic feeding starts to restrain the appearance of the shrinkage and porosity when L = 0 mm and D = 60 mm, where the effective Joule heat generated by the induction coil occupies about 75% of the energy dissipated in the riser solidification process, at least. The better feeding effect can be obtained at L = 0 mm and D = 40 mm in consideration of the thickness of the insulation board.

Performance optimization design of lightweight composite thermal insulation structure for vehicle shelter

Aiming at the thermal insulation problem of vehicle shelter in high heat and cold environment, with polyurethane foam as the base material, vacuum insulation board and aerogel with low thermal conductivity as the core material, a new composite insulation structure called dual-core cladding thermal insulation structure suitable for vehicle shelter is proposed. Based on the secondary development of ANSYS, the batch CFD simulation of the sample points of the dual-core cladding thermal insulation structure is realized, and it is concluded that its surface density increases linearly and effective thermal conductivity decreases nonlinearly with the increasing of thickness of the core material. Comparing with aerogel, the thickness of the vacuum insulation board has a more obvious influence on the performance of the insulation structure. The proxy model and the second-generation non-inferior ranking genetic algorithm are used to perform the multi-objective optimization of performance of the dual-core cladding thermal insulation structure. After optimization, the effective thermal conductivity of the thermal insulation structure reduced by 55.56%, and the thermal insulation effect is better than that of the single-core thermal insulation structure. The new dual-core cladding thermal insulation structure was applied to the middle roof of a vehicle shelter, the analysis results showed that the heat transfer coefficient of the middle roof reduced by 15.76% under the requirement of surface density, which improved significantly the heat insulation performance of the vehicle shelter slab.

少量データにおける畳み込みニューラルネットワークを用いた基板そり量変位の予測

A convolutional neural network, which reproduce a function by data, was used to predict the amount of warp distortion of a four-layer circuit board in a reflow soldering process. The data used for training are material properties such as Young's modulus, board thickness, and residual copper content as input data, while the warpage strain data to be predicted is the amount of warp of the circuit board obtained from the measurement. Since several distortion data to be predicted was insufficient to be used for training, a newly proposed data augmentation method used to increase a total amount of data. Proposed data augmentation is evaluated through the result of the predictions and discussed.