Dry Board Research Articles

Can diameter and log end splittings be a good indicator of board end splitting in 21-year-old Eucalyptus grandis Hill ex-Maiden?

Eucalyptus spp. are currently cultivated in Brazil. In this article we highlight Eucalyptus grandis with its potential for mechanical processing. After felling trees, the splitting that occurs at the end of logs and boards obtained during mechanical processing represents an indirect measure of the level of growth stress present in the living trees. Even though such splitting can cause significant losses in the use of wood, knowledge of this pattern is still sparse. The most suitable eucalyptus trees for the production of sawn wood can be selected by evaluating the effect of the release of growth stresses in the form of cracks. To address this gap, we herein evaluate the effects of end splitting in logs and boards, resulting from the release of growth stresses during the felling of trees and mechanical processing, as a function of the diameter of 48 Eucalyptus grandis Hill ex-Maiden trees aged 21 years old. Splitting at the ends of boards in the green and dry states have a low relationship with the diameter of the logs, but it is not related to the end splitting of the tree logs. A high positive relationship was found between dry board splitting and green board splitting. Therefore, it is possible to estimate with accuracy the evolution of green board splitting according to the drying of the wood. Boards lose, on average, 44 cm (15%) from cracks, or an average of 32 cm (11%) from growth stresses and 12 cm (4%) from drying stresses. Green and dry board splitting decreased significantly from pith to bark. The splitting of dry and green boards had no significant variation between the analyzed positions of the log along the height of the tree.

Prediction of the Bending Strength of a Composite Steel Beam-Slab Member Filled with Recycled Concrete.

This study investigated the structural behavior of a beam-slab member fabricated using a steel C-Purlins beam carrying a profile steel sheet slab covered by a dry board sheet filled with recycled aggregate concrete, called a CBPDS member. This concept was developed to reduce the cost and self-weight of the composite beam-slab system; it replaces the hot-rolled steel I-beam with a steel C-Purlins section, which is easier to fabricate and weighs less. For this purpose, six full-scale CBPDS specimens were tested under four-point static bending. This study investigated the effect of using double C-Purlins beams face-to-face as connected or separated sections and the effect of using concrete material that contains different recycled aggregates to replace raw aggregates. Test results confirmed that using double C-Purlins beams with a face-to-face configuration achieved better concrete confinement behavior than a separate configuration did; specifically, a higher bending capacity and ductility index by about +10.7% and +15.7%, respectively. Generally, the overall bending behavior of the tested specimens was not significantly affected when the infill concrete's raw aggregates were replaced with 50% and 100% recycled aggregates; however, their bending capacities were reduced, at -8.0% and -11.6%, respectively, compared to the control specimen (0% recycled aggregates). Furthermore, a new theoretical model developed during this study to predict the nominal bending strength of the suggested CBPDS member showed acceptable mean value (0.970) and standard deviation (3.6%) compared with the corresponding test results.

Flexural Performance of a Novel Steel Cold-Formed Beam–PSSDB Slab Composite System Filled with Concrete Material

In this study, the flexural performance of a new composite beam–slab system filled with concrete material was investigated, where this system was mainly prepared from lightweight cold-formed steel sections of a beam and a deck slab for carrying heavy floor loads as another concept of a conventional composite system with a lower cost impact. For this purpose, seven samples of a profile steel sheet–dry board deck slab (PSSDB/PDS) carried by a steel cold-formed C-purlins beam (CB) were prepared and named “composite CBPDS specimen”, which were tested under a static bending load. Specifically, the effects of the profile steel sheet (PSS) direction (parallel or perpendicular to the span of the specimen) using different C-purlins configurations (double sections connected face-to-face, double separate sections, and a single section) were investigated. The research discussed the specimens’ failure modes, flexural behavior, bending capacity, bending strain relationships, and energy absorption index of specimens. Generally, the CBPDS specimens with the PSS slab placed in a parallel direction achieved approximately a 13–40% higher bending capacity compared with the corresponding specimens with a perpendicular PSS direction (depending on the configuration of the beam). Fabricating the beam of the CBPDS specimen with double C-purlins (face-to-face) led to more effective concrete confinement behavior compared with the double separate C-purlins beam. The related specimen recorded a 10% higher bending capacity. Finally, the suggested composite CBPDS system exhibited a sufficient energy absorption capability of the static bending load because it demonstrated high strength and high ductility.

A Preliminary Study on Vibration Response of Profiled Steel Sheet Dry Board (PSSDB) System under Heel-drop Test

This paper aims to evaluate the vibration response of the profiled steel sheet dry board (PSSDB) composite system under heel-drop test. Three (3) specimens with dimensions of 840mm width and 2000mm length were prepared. The specimen consists of a sample without concrete infill (P45HL), foamed concrete as infill (P45FC), and normal concrete as infill (P45NC) material. The specimen was erected using profiled steel sheet (PSS), 1mm thickness, and connected to a dry board (DB), 16mm thickness using self-drilling screws at 200mm screw spacing along the longitudinal direction. A heel-drop test was conducted, and modal analysis was performed using MEscope software. The FRF measurement was carried out using accelerometers, and the time-domain measured responses were converted to FRF to acquire modal characteristics such as natural frequency and mode shape of the structures. The natural frequency of the first mode shape is 17.7Hz, 14.2Hz, and 4.5Hz respectively for specimen P45H, P45FC, and P45NC. It demonstrates that the natural frequency of the specimen without infill and foamed concrete as infill is more than the human comfort limit value of 8Hz, implying that P45HL and P45FC will be comfortable for building occupants.

Numerical investigation for the flexural load behaviour of profiled composite slab strengthened with CFRP

The profiled composite slab (PCS) is a composite structural system consisting of profiled steel sheet in-filled with concrete in the troughs and connected using studs. This system is a structural load bearing element. Lately, this system has been increasingly used as flooring or roofing structural element. The PCS has become as an extension or development to the most popular now a day's composite slab called profiled steel sheet dry board which was brought to the United Kingdom as an alternative to timber joist flooring for small span domestically buildings. Similarly, to other structural members, PCS demands strengthening and continuous upgrading due to many reasons like exposing to accidents or to improve its ability to bear an extra load. There are a quite limited studies related to the improvement of the PCS strength thus, this study suggests investigating the effect of using carbon fiber reinforced polymer (CFRP) plates to strength the PCS and enhance its ability to carry an extra load. Three parametric studies were considered in this study, the effect of thickness, length and location of the CFRP plates on the flexural load behaviour. The FE analysis results, proved that using CFRP as a strengthen technique for the PCS system has a positive effect on the ultimate flexural bearing capacity which increased by 16.5%, 29.5% and 41.0% using different CFRP plate thickness (1.5, 3.0, and 4.5 mm, respectively). Moreover, when different CFRP plates length (1000, 1500 and 2000 mm) were used the ultimate flexural bearing capacity raised up to 4.0%, 10.0% and 16.5% respectively while the amount of increment were 16.5% and 39.0% when using different CFRP number of sheets (2 and 4 sheets respectively). Lastly, this study strongly recommends using CFRP sheets as a strengthen technique for the PCS system.

Experimental and analytical investigation on shear behavior of profiled steel sheet dry board composite wall system

Profiled steel sheet dry board (PSSDB) composite wall/panel system with advantages (like lightweight, enhanced flexibility, low-cost, simple pre-fabrication/erection process, no temporary formwork requirement etc.) is an innovative construction technology that has significant potential to be used as a viable alternative to its conventional counterparts in earthquake prone region. No significant research study is available on the structural behavior of PSSDB composite walls under in-plane shear loading. Nineteen PSSDB panels consisted of single profiled steel sheet (PSS) assembled with single or double plywood dry board (DB) are tested under shear loading to failure. The effects of boundary frame, central opening, concrete in-fill, fastener orientation, and panel geometry on load-deformation response, strength and failure modes are investigated and compared. Analytical models for shear capacities of PSSDB composite system of various configurations are developed based on modified code-based/existing equations and their performance validated using experimental results. These analytical models can be used by engineers in designing PSSDB composite system for practical construction.

Structural Behavior of Lightweight Composite Slab System

This study investigate the structural behavior of lightweight composite slab system that consist of profiled steel sheet (PSS) attached to dry board (DB) using mechanical screws and with or without infill materials. A total four full-scale panel specimen were tested under four-point bending when subjected under static loading. Result of the four-point test shows that increasing the thickness of profiles steel sheet gives major effect to the deflection and ultimate load. The deflection and ultimate load of 1.0mm thick panel specimen is 16.45% and 34.45% respectively. Therefore, increased the thickness of profiled steel sheet can enhance the stiffness and strength of the lightweight composite slab systems. It also found that the infill material used in these experimental gives minor effect to deflection and ultimate load. The deflection and ultimate load of panel specimen with foamed concrete is 21.18% and 16.66% respectively. Thus, foamed concrete can be used only for non-structural purposed only such as sound proofing and fire resistance.

Copolymerization of UF Resins with Dimethylurea for Improving Storage Stability without Impairing Adhesive Performance.

Urea-formaldehyde (UF) resins are the most used resins in the wood industry due to high reactivity and low price. However, their reduced stability during storage is a drawback, imposing strict limits in terms of allowable shipping distances and storage times. This instability, manifested by viscosity increase that renders the resin unusable, occurs due to the progress of condensation reactions between the polymeric species present in the liquid medium. In order to achieve a stable resin formulation, dimethylurea (DMeU) was selected for being less reactive than urea. Dimethylurea is shown to co-polymerize with the UF polymer during the acidic synthesis condensation step. However, during storage it behaves like an end group blocker, due to its lower reactivity at basic pH. By adding 1.25% DMeU, it was possible to obtain a formulation that remained with stable viscosity during two-month storage at 40 °C. The reference UF resin remained stable only for eight days in these conditions. Wood particleboards produced with modified resins showed internal bond strengths of about 0.5 N·mm−2, similar to the fresh reference UF resin, even when the resins were used after the two-month storage period. Formaldehyde content values were below the limit for E1 class, ≤8 mg/100 g oven dry board (EN 13986).

How ICT Affects the Understanding of Stereometry Among University Students

The purpose of this research is to compare the level of competence in stereometry of the university students taught using the authors' ICT oriented learning method based on the Van Hiele model for stereometry concepts, as opposed to traditional teaching methodology. The study deals with second year undergraduate students form the Department of Civil Engineering at Piraeus University. The sample was divided into two groups. The experimental group consisted of 99 students who were taught about basic concepts of solid geometry with the support of computers based on the Van Hiele model. Also, there were 90 students in the control group which were taught with traditional methodology using a dry erase board. The study results showed that teaching and learning through ICT is an interactive process for second year university students and has a positive effect on learning solid geometry concepts using the background of the Van Hiele model.

The two-way flexural performance of the PSSDB floor system with infill material

This paper investigates the structural performance of the Profiled Steel Sheeting Dry Board (PSSDB) system; a lightweight composite structure which is made by binding a Profiled Steel Sheeting (PSS) to a Dry Board (DB) by mechanical screws. Many studies indicated that it can be used as flooring units. However, most of them focused on utilizing the system as a one-way floor panel. It's rare to find studies that consider the two-way position, and so far none has ever considered the effect of the infill material in that situation. Therefore, the purpose of this paper is to investigate the flexural performance of the two-way PSSDB floor panel with the presence of the infill material. An Experimental (EXP) and Finite Element (FE) approaches were employed. For the EXP tests, it was found that applying a steel plate (SP) can enhance the stiffness and strength of the PSSDB system by approximately 31% and 15%. The results were used to compare with the ones of a previous study, and it was shown that applying infill material can improve the strength by 13.2%. Applying both Steel Plate (SP) and infill material instead of SP alone can enhance it by 13.6%. As for the FE approach, it was demonstrated that changing the thickness of the DB and SP has a minor effect by no more than 5%, while changing the PSS's thickness can affect the performance by up to 18.3%. And finally, the effect of changing the type of infill material is less than 1%.

Theoretical and finite element analysis of the two-way PSSDB floor system

The profiled steel sheet dry board (PSSDB) system is a lightweight composite structure which consists of profiled steel sheeting connected to dry board by self- tapping and self-drilling screws. It can be used as flooring, walling and roofing panels. This paper presents the investigation of the two-way flexural behavior of the PSSDB floor system. The study employs both theoretical and non-linear finite element (FE) analysis. The FE approach has been done using ABAQUS software. While the theoretical one was conducted using an elastic full interaction analysis. The obtained results were verified against experimental tests and it was shown that both the theoretical and FE solutions are adequate enough to predict the behavior of PSSDB system. After that, several parametric studies have been conducted to have a better comprehension of the factors that affect the behavior of the system. It was found that the changing the dry board depth can enhance the behavior up to 23%. However changing the type of board has a minor effect on the elastic stage and it starts increasing in the plastic period up to 14%. Also, it was shown that changing the thickness of steel sheeting can affect the performance by approximately 18%. Screw spacing has an impact on the strength of the system up to 9.6%. Finally, applying line load has demonstrated a better two-way action than point load.

INVESTIGATION ON THE DEGRADATION BEHAVIOR OF CREEPAGE DISCHARGE ON PRESSBOARD IMMERSED IN PALM FATTY ACID ESTER (PFAE) OIL

Creepage discharge at the oil-pressboard interface is known as the development of a conducting path which is characterized by white and carbonized marks. This phenomenon tends to cause damage on the cellulose pressboard insulation which is subsequently promote to the catastrophic failure of a transformer. One of major defects that may cause the creepage discharge to occur along the pressboard surface is an excessive moisture content in pressboard insulation. Previously, there is an extensive research concerning the effect of moisture content in pressboard on the degradation of creepage discharge at mineral oil-pressboard interface. However, none has been found on the study of the effect of moisture content in pressboard on creepage discharge using ester oil. Therefore, this paper attempts to present the investigation on the degradation behavior of creepage discharge at Palm Fatty Acid Ester (PFAE) oil-pressboard interface by using a needle-bar electrode configuration under a constant AC voltage. Dry and wet pressboard samples (moisture content of 3 %) are used in this experiment to differentiate the degradation behavior. The development of creepage discharge is analyzed by correlating the visual records of creepage discharge and phase-resolved partial discharge (PRPD) pattern. An unexpected result has been found that the number of partial discharges (PDs) for wet pressboard is lower than the dry one as the formation of white mark with bush-like pattern is observed. Eventually, as the white mark is seen about halfway of the gap distance, the PDs number for wet pressboard sample significantly dropped, i.e. by 99 % compared to the dry board which is only 38 %. Variations in the PRPD data is due to constructive and destructive superpositions of electric field. The results suggest that the destructive effect is higher on the wet pressboard compared to the dry one.

Experimental Tests on Bending Behavior of Profiled Steel Sheeting Dry Board Composite Floor with Geopolymer Concrete Infill

PROFILED STEEL SHEET DRY BOARD (PSSDB) SYSTEM IS A LIGHTWEIGHT COMPOSITE STRUCTURE COMPRISES PROFILED STEEL SHEETING AND DRY BOARD CONNECTED BY SELF-DRILLING AND SELF-TAPPING SCREWS. THIS STUDY INTRODUCED GEOPOLYMER CONCRETE, AN ECO-FRIENDLY MATERIAL WITHOUT CEMENT CONTENT AS AN INFILL MATERIAL IN THE PSSDB FLOOR SYSTEM TO HIGHLIGHT ITS EFFECT ONTO THE PSSDB (WITH FULL AND HALF-SIZE DRY BOARDS) FLOOR SYSTEM€™S STIFFNESS AND STRENGTH. EXPERIMENTAL TESTS ON VARIOUS FULL SCALE PSSDB FLOOR SPECIMENS WERE CONDUCTED UNDER UNIFORMLY DISTRIBUTED TRANSVERSE LOADS. RESULTS ILLUSTRATE THAT THE RIGIDITY OF THE PANEL WITH GEOPOLYMER CONCRETE INFILL WITH HALF-SIZE DRY BOARD (HBGPC) INCREASES BY 43% RELATIVE TO THAT OF THE PANEL WITH NORMAL CONCRETE INFILL WITH FULL-SIZE DRY BOARD (FBNC). THE DEVELOPED FINITE-ELEMENT MODELING (FEM) SUCCESSFULLY PREDICTS THE BEHAVIOR OF FBGPC MODEL WITH 94.8% ACCURACY. GEOPOLYMER CONCRETE INFILL AND DRY BOARD SIZE INFLUENCE THE STRENGTH PANEL, INFILL CONTACT STIFFNESS, AND MID-SPAN DEFLECTION OF THE PROFILED STEEL SHEETING/DRY BOARD (PSSDB) FLOORING SYSTEM.

Experimental Test and Non-Linear Finite Element Modeling Prediction on Profiled Steel Sheeting Dry Board (PSSDB) with Geopolymer Concrete Infill

Profiled steel sheeting dry board (PSSDB) system is made of profiled steel sheeting that is connected to the dry board using a self-drilling, self-tapping screw. This study aims to predicts the load-deflection behavior of PSSDB panel system under the influence of geopolymer concrete infill with finite element modeling. To achieve the target objective, the laboratory testing approach and a theoretical system behavior prediction are considered. Through a bending test, the stiffness of PSSDB full board with geopolymer concrete infill (FBGPC) panel is 27.42 kNm2 and the ultimate load is 13.13 kN/m2. The developed finite-element modeling (FEM) successfully predicts the behavior of PSSDB with geopolymer concrete infill panel with >85% accuracy.

An Evaluation of Biological Approach for the Effluent Treatment of Paper Boards Industry - An Economic Perspective

The environmental problems of paper board industry are not limited by the high water consumption, generate wastewaters and solid wastes. This paper presents the paper board industry effluent treatment plant components performance and physio-chemical characteristics of wastewater and sludge. In ETP operation most important factors is effluent characterization, flow rate, aeration tank dissolved oxygen (DO) level, mixed liquid suspended solids (MLSS), food to micro-organism ratio (F/M), sludge volume and chemical addition for nutrients and coagulant. The wastewater is characterized by extreme quantities of pH, total dissolved solids (TDS), total suspended solids (TSS), biochemical oxygen demand (BOD), chemical oxygen demand (COD) and the solid waste from ETP sludge is characterized by SEM –EDX and ICP. The wastewater samples were collected from the partied of one month influent and treated effluent. An influent consist pH of 7.1-7.7, TSS of 1160-1380 mg/L, TDS of 1500-2000 mg/L, BOD and COD varies 200-250 mg/L and 2010-1286 mg/L respectively. The treated effluent of pH varies 7.1-7.3, TSS 10-20 mg/L, TDS ranges from 1500-1900 mg/L, BOD and COD ranges from 7-16 mg/L and 54-145 mg/L, respectively. Further solid waste in the form of sludge handled through mechanical dewatering devise (belt press). The result shows that the performance of effluent treatment plant based on the permissible limits prescribed by regulatory agencies and can be recycle an entire treated effluent into the board manufacturing process. The fixed capital cost was 700 lakhs- Indian Rupees (Rs.) and annual operation and maintenance cost was estimated Rs. 180 lakhs (without RO plant). Reuse of treated effluent in pulp process and sludge in sun dry board manufacturing and composting were adopted to achieve the target of sustainable development for ecological and economical gains.

Effect of Geopolymer Concrete Infill on Profiled Steel Sheeting Half Dry Board (PSSHDB) Floor System Subjected to Bending Moment

Profiled Steel sheeting Dry Board (PSSDB) system is a lightweight composite structural system consisting of profiled steel sheeting, mechanically connected to a dry board using self-drilling and self-tapping screw. The objective of this study is to investigate the effect of geopolymer concrete infill in PSSDB system with half board (PSSHDB), focus on its deflection serviceability limit at mid-span region. Geopolymer concrete was chosen to be as infill in the PSSDB floor system due to its high compressive strength as compared to normal concrete and its potential as an alternative concrete since it does not utilize Ordinary Portland Cement (OPC). This study used a modified PSSHDB panel using a half-sized dry board. In achieving this objective, forecasting the behavior of the system in laboratory experiments will be taken into account as the research approach. Experimental results found that with the use of geopolymer concrete infill, the mid-span deflection on the PSSHDB floor system can be reduced to 41% as compared to the use of normal concrete infill. This indicates an increase in the stiffness of this system due to the effect of infill geopolymer concrete.

The Performance of Double Sheathed Composite Walling Made from Profiled Steel Sheeting and Dry Board

This paper presents the performance of an emerging prefabricated composite system made from profiled steel sheeting and dry board. Six full-scale wall specimens were prepared and tested under axial load. The results of the experimental investigation showed that the performance of the composite walls is governed by the strength of profiled steel sheeting while the dry board performed as a wall sheathed. A partial interaction between the profiled steel sheeting and dry board was achieved by using self-drilling screws. The maximum axial load capacity is 1329kN for the double sheathed wall. The failure behavior of single and double sheathed composite wall exhibited similar pattern such as global buckling and cracking. The developed composite wall system was found the great potential in prefabricated and modular construction in Malaysia.

Comparative Study Floor Flexural Behavior of Profiled Steel Sheeting Dry Board between Normal Concrete and Geopolymer Concrete In-Filled

This study investigates the behavior of in-filled materials of profiled steel sheeting dry board (PSSDB) floor system. Two tests were conducted, namely, push-out test to know the connection stiffness and bending test on the PSSDB panel under the influence of different in-filled materials. Result of the push-out test shows that the connection stiffness of the geopolymer concrete-filled PSSDB is 331% higher than that of PSSDB that is filled with normal concrete. This connection stiffness contributed to the reduction of deflection value of 21% in the middle of the midspan for full-board geopolymer concrete in-filled panel bending test. This phenomenon triggered the increase of interaction within the composite system, making the panel that is filled with the geopolymer concrete 25% stronger than the normal concrete–filled panel.

Formaldehyde emission in wood based panels: effect of curing reactions

The influence of hexamine formed as byproduct during the UF cure was ignored in the past. However, with the increasing interest on low formaldehyde emission boards, this issue has become more pertinent. Formaldehyde release from hexamine degradation is extensive and could limit the success of the development of low formaldehyde emission adhesives if the conventional latent catalysts remain in use.In this study, formaldehyde released from recycled wood, hexamine and cured UF resin was assessed. Citric and oxalic acid, in solid form, were used as catalysts for UF resin in the production of particleboard. Mats with solid acids are less susceptible to resin pre-cure than with a latent catalyst. However, they can have higher formaldehyde emissions than latent catalyst. When both catalysts were used, combined with an ultra-low formaldehyde to urea molar ratio resin the internal bond was improved and formaldehyde content was below 4 mg per 100 g of oven dry board.

Non-linear analysis of membrane action effect in profiled steel sheeting dry board flooring system

This study highlights the effect of membrane action in improving load carrying capacity of Profiled Steel Sheeting Dry Board (PSSDB) floor system. PSSDB system is a lightweight composite structural system composed of profiled steel sheeting and dry board, attached together by self-drilling and self-tapping screws. Many literatures have reported that restricting conventional slabs, such as reinforced concrete slab, at the supports against translation and/or rotation while it is subjected to vertical loading develops the compressive membrane action in the slab. The development of this phenomenon is considered in the PSSDB system with concrete infill for continuous and practical spans, with and without topping concrete. Previous authors’ experimentally verified non-linear finite element model for the PSSDB floor without topping was extended to parametrically predict the effect of different boundary conditions on the performance of the system for practical applications. It was revealed that preventing the in-plane movement of the slab ends improves the flexural rigidities of the slab up to more than three times when considering central deflection of serviceability limit state. This was observed when the deflection limit load of the fixed both end supports model was compared to the pin-roller support model. Moreover, the topping concrete enhances the applicability of the system in longer span and the developed compressive membrane action dramatically boosts the load carrying capacity of the slab with restricted translation and/or rotation of the slab ends.