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Medium density fibreboard (MDF) is extensively used in the construction and furniture industry, especially as building materials, household furniture, fencing and flooring because of its desirable properties such as being low cost, having excellent mechanical and physical properties and being isotropic. However, the sustainability of wood supply has become a serious environmental issue. Therefore, it is necessary to find alternative strategies in order to reduce the wood demand for producing wood-based composites such as MDF. This article reviews the various alternative materials such as wheat straw, kenaf, corn stalk, sisal and bagasse to reduce the dependency on wood in the related industries. Moreover, this article also reports on the development of environmental friendly adhesives and non-adhesive MDF to reduce the emission of formaldehyde which is a carcinogen agent and may lead to various health problems.

The use of more efficient and greener insulation products is a strategy that is being followed to achieve more sustainable energy efficient buildings. Given these concerns, expanded cork boards, which are 100% natural and recyclable, are being used more often as the only coating for building facades, without any additional protection. In this context, this work evaluates the performance of standard (90–110 kg/m3) and medium (140–160 kg/m3) density expanded cork boards to be applied as an uncoated solution for building facades and roofs. As the building envelope is exposed to external conditions (wind pressure, rain, temperature and moisture gradients, sunlight and mechanical loads), a wide range of laboratory tests were performed to evaluate their mechanical, hygrothermal and durability characteristics. It was found that the medium density cork board is more suitable for the uncoated external insulation of building facades and roofs, since it has a better mechanical performance, without compromising its hygrothermal behaviour. It was found that it is also resistant to long-term exposure to external conditions.

The objectives of this work was to evaluate the adhesion strength of thermally compressed and varnished veneer used as overlay on medium density fibreboard (MDF) panels. Rotary cut birch veneer sheets were compressed at temperature levels of 150 °C, 180 °C and 210 °C before they were bonded MDF substrate. The varnish was applied to the surface of the samples at various layers and spread rates. Based on the findings of this study compression temperature significantly influences overall adhesion strength of the samples. Since thermal compression process resulted in uniform surface quality of both loose and tight sides no significant difference between them regarding their adhesion strength characteristics was determined. It was also determined that adhesion strength values of compressed and varnished samples had higher values than those of control samples.

This paper measures the excess demand for apartments in Australia’s largest cities. We estimate that homebuyers will pay an average of $873,000 for a new apartment in Sydney though it only costs $519,000 to supply, a gap of $355,000 (68 per cent of costs). There are smaller gaps of $97,000 (20 per cent of costs) in Melbourne and $10,000 (2 per cent of costs) in Brisbane. The large gaps are sustained by planning restrictions. The shortage of apartments is most severe in the inner suburbs of Sydney, where height limits prevent more construction. Elsewhere, restrictions on converting low density housing to apartments are important. High rise apartments are a much less costly means of supplying extra housing than the medium density housing that some planners favour.

This paper evaluates the influence of the solar heat flux, temperature, and relative humidity on OSB and concrete walls covered with uncoated medium density expanded cork. A boundary element numerical model was used to simulate the coupled heat and moisture transfer through the multi-layer porous solid walls. The expanded cork hygrothermal properties were determined experimentally. After experimental validation of a building solution using a hotbox, numerical simulations were performed to evaluate the effect of the abrupt change in relative humidity and temperature. It was concluded that the relative humidity variation is only relevant when there are significant weather changes during the course of the year. Thus, the summer and winter conditions of Braganca (Portugal) and Seville (Spain) were selected to illustrate the hygrothermal behaviour of the walls. Different thicknesses of expanded cork were simulated. The results show that the impact of the short-term environment moisture variation is limited to the outer surface layers. It was also found that the moisture along the medium density expanded cork coated wall is only high when the outer moisture is high and remains high for a long period of time.

Modeling and control of a multi-medium unmanned vehicle capable of seamless operation in air or underwater is introduced in this paper. The multi-medium system is treated as a hybrid system with continuous dynamics while performing in both air and underwater, and discrete jumps in the medium density during the transitions. The continuous dynamics are modeled by the Newton–Euler formalism, taking into account the effects of the buoyancy and drag phenomena, normally neglected in aerial vehicles. A hybrid controller is designed for trajectory tracking considering the full system, including a transition strategy to assure the switching between mediums. Stability analysis for the full system is provided using hybrid Lyapunov and invariance principles. The performance of the control strategy is validated through simulations. Finally, an experimental platform consisting of a multirotor in an octo-quadcopter configuration was developed and some preliminary experimental results are introduced, showing the vehicle performing in air, underwater and through the transition.

Wood surfaces are typically sanded before the lacquer coatings technological processes. This article discusses the aesthetic properties of lacquer coatings formed on medium density fibreboard (MDF) panels, veneered with thermally compressed birch wood. The effect of thermal compression temperature, veneer side (loose vs. tight), the number of lacquer layers and spread rates on the gloss unit (GU) of lacquer coatings were determined. Rotary-cut birch veneer sheets were thermally compressed at various temperatures (150, 180 and 210 °C) and afterwards they were bonded to the surfaces of MDF panels. The lacquer was applied to the surface of veneered MDF panels in 1, 2 and 3 layers at the various spread rates, appropriate 50, 75 and 100 g/m 2 . The values of GU parameter were measured at three angles − 20, 60 and 85°. Statistical evaluation of GU parameter showed, that the number of layers, the amount of lacquer, the direction of wood fibers, the side of veneer and compression temperature significantly affect gloss of the surfaces of veneered MDF panels. Gloss increased with the number of layers and the amount of applied lacquer. Brightness decreases with the increase in temperature from 150 to 180 °C, while a further increase in temperature from 180 to 210 °C enhances GU. There is a significant difference between values of gloss (except for the 20° angle) measured along and across grain direction. The values of gloss measured along the wood fibers are higher than those measured across the grains. Thermal compression of veneer homogenises the surface and as a result the gloss of the loose and tight sides is uniform. Thermal compression of birch wood surface instead of its sanding before finishing improves aesthetic properties of wood, in particular surface gloss as well as reduces the required lacquer application rate. These findings make it possible to improve the technology of lacquer coatings of thermally compressed wood.

Generation and availability of agro-industrial waste in the world present an opportunity to obtain raw materials for the development of new sustainable materials. In order to contribute to the dissemination of using agro-industrial residues in lignocellulosic particleboard (eco-particleboard) manufacturing, this work aimed to investigate the influence of a chemical mercerization treatment on the physical and mechanical properties of eco-particleboards. The treatment consisted of 0.5% sodium hydroxide (NaOH). Results of analysis of variance (ANOVA) revealed that treating the fibers was responsible for significantly reducing water absorption by 35% (2 h) and 17% (24 h), as well as thickness swelling by 36% (2 h) and 40% (24 h). The apparent density of treated (WT) and untreated (UT) eco-particleboards showed homogeneity and uniformity of the test specimens analyzed, mainly due to the manufacturing process in eco-particleboard pressing. The efficiency of the chemical mercerization treatment of the fibers of acai fruit eco-particleboard (WT) was established because the eco-particleboard produced with these fibers showed higher values in their mechanical properties: screw pullout (top) 54%, modulus of rupture in static bending (31%), and internal bonding (89%) compared to eco-particleboards composed of untreated fibers (UT). The physical-mechanical results presented by the eco-particleboards composed of treated acai fibers (WT) suggest that acai fibers could be a potentially useful raw material for the production of medium density homogeneous particleboards and consequent commercial use in the construction and furniture industries.

A series of 1:20 small-scale tunnel experiments have been carried out as a scaled down representation of a previously undertaken large-scale heavy goods vehicle (HGV) cargo load tunnel fire experiment. The small-scale tunnel has dimensions of 0.365 m (W) × 0.260 m (H) × 11.9 m (L) and a maximum forced ventilation velocity of 0.68 m/s is adopted corresponding to the velocity of 3 m/s used at large-scale. A gas burner and cribs constructed of medium density fireboard (MDF) have been used as the fuel sources with temperatures, heat release rate (HRR) and velocity data recorded in the small-scale tunnel experiments. A scaled down HRR curve derived from the large-scale experiment was reproduced by the gas burner. Temperatures in the small-scale gas burner experiment can effectively represent those at large-scale during the fire growth and decay stages although measurements at the fully developed stage are lower than the results from the large-scale tunnel experiment. In the small-scale tunnel experiments using the cribs time delays are applied to correct the recorded data in order to obtain the instantaneous HRR. Temperature profile comparisons between the small-scale crib and large-scale HGV cargo load experiments are not applicable since the HRR curves from the crib experiments only approximately reproduce the large-scale HRR profile.

This paper presents the findings from comprehensive studies for enhancing efficiency and competitiveness of wood based panels for uses in furniture and other building construction industries. Five stress modes, which are encountered in the design and applications of wood based panels, were investigated, i.e. flat-bending, edgewise-bending, panel shear, planar shear and concentrated load stresses. Four commercial board types, namely plywood (PW), particleboard (PB), medium density fibreboard (MDF) and oriented strand board (OSB), were examined to evaluate the different responses to the various stresses. Results showed that stress modes had a significant effect on both short- and long-term performance of wood based panels: 1) wood based panels had a much higher capability to carry the stresses applied along the edge than plane of the panels, 2) the maximum failure load under planar shear was 10–16 times that under flat bending load and 2–3 times that under concentrated load, and the maximum failure load under panel shear was 3–9 times that under pure edgewise bending load, 3) for the materials tested, PW had a higher capability to carry both pure edgewise bending load and concentrated load, and MDF had a higher capability to carry pure flat bending load, and panel and planar shear load, 4) stress modes had a more significant effect on deflection under creep loading than short term test, with the ratio of deflection under flat bending, concentrated load and planar shear being 23:6:1 for PW under short term test, while 205:20:1 for PW and 507:72:1 for PB under creep loads, 5) theoretically calculated deflection was higher than the measured for short term tests but lower than the measured for creep tests, 6) the effect of stress modes on relative creep varied among the materials tested. These findings provide most constructive database for designing and using wood based panels in various industrial sectors.

This paper presents insights into the response and failure of medium density fibreboard (MDF) panels subjected to air-blast loading. The MDF panels are representative of a cheap, and potentially sustainable, structural material that is commonly used in homes and buildings. Simplified computational simulations were used to design a series of air-blast experiments to elucidate a range of responses and failures within the MDF. The blast-loaded MDF panels exhibited multiple surface cracks, substantial in-plane cracking throughout the less dense parts of the cross-section, and fragmentation failures. The transient results show MDF exhibits peak displacement that are many times greater than the permanent deformation, and that the internal damage due to cracking reduced the stiffness of the panels. These findings provide unique and detailed insights into the cracking and fragmentation of MDF that will prove valuable to blast protection engineers considering the effects of explosive detonations inside buildings containing MDF furnishings, and any increased risk of secondary blast injuries due to flying MDF debris. The experimental data can be used by modellers to validate simulations of damage due to explosive events in the future.

This study aims to quantify the flammability limits of the pyrolysate gases produced from thermally decomposed medium density fibreboard (MDF) and plywood. Finding the flammability limits of the pyrolysate gases is believed to assist in studying the smoke explosion phenomena as smoke explosion is known to be caused by gradual transformation of the oxygen and smoke gas mixture to a flammable mix. A novel gas generation apparatus is developed to generate pyrolysate products from thermally decomposed engineered wood materials, filter the aerosols and condensates, and store the pyrolysate gas in a sealed chamber. The flammability of the pyrolysate gas is then tested in a flammability testing apparatus similar to the apparatus developed by the U.S. Bureau of Mines. The operation of the flammability test apparatus is verified by measuring the flammability limits of methane. The flammability limits of MDF and plywood pyrolysate gases found by experiments are in good agreement with the flammability limits found based on the species distribution of engineered wood pyrolysis, reported by other researchers. Quantifying the flammability characteristics of engineered wood pyrolysate gases is part of ongoing research to understand the effect of smoke species on fire behaviour and on the occurrence of smoke explosion.

Research has demonstrated the positive impacts of contact with nature on people’s physiological and psychological health. However, few studies have discussed the effect of vegetation from the perspective of landscape ecology. This study aims to explore people’s physiological and psychological responses to varying locations and vegetation density. We recruited 180 participants and randomly assigned them to three locations and three density conditions: forest interior, forest edge, forest exterior, high density, medium density, and low density. We used an electroencephalogram (EEG) to monitor participants’ Alpha waves as they watched a slide show using 3D glasses, followed by a Stroop task and a Profile of Mood States questionnaire. Results suggested that the forest interior condition induced significant stress recovery and received the highest preference score, whereas the forest edge was associated with better attention restoration effects. In terms of vegetation density, the high-density group showed better attentional functioning, but the medium vegetation group was more preferred. The results may offer guidance for designers regarding site selection and vegetation arrangement to achieve optimal restorative effects.

Hydrocyclones can be applied to recycle waste plastics with different densities through separating plastics based on their differences in densities. In the process, the medium density is one of key parameters and the value of the medium's density is not just the average of the density of two kinds of plastics separated. Based on the force analysis and establishing the equation of motion of particles in the hydrocyclone, a formula to calculate the optimum separation medium density has been deduced. This value of the medium's density is a function of various parameters including the diameter, density, radial position and tangential velocity of particles, and viscosity of the medium. Tests on the separation performance of the hydrocyclone has been conducted with PET and PVC particles. The theoretical result appeared to be in good agreement with experimental results.

Pyrolysis experiments were conducted on medium density fibreboard (MDF) in inert atmosphere and different ambient pressures, to investigate the char shrinkage and cracking. It is found that the cha ...

In this study, non-metallic waste from printed circuit boards (PCBs) and waste automotive plastics (WAP) were used to produce sustainable composite panels, with a wide range of potential uses comparable to products such as MDF (medium density fibreboard). The composite panels, made from differing proportions of non-metallic PCB waste and WAP, were fabricated by using a hot press. The physical properties of the fabricated panels were studied by density measurements. The panels were characterised mechanically through flexural, tensile and compression tests and fractured surfaces were observed using scanning electron microscopy (SEM) for interface interaction studies. The density of the produced panels increased linearly, as the proportion of non-metallic PCB waste increased, in a range of 0.956 g/cc for 100/0 (WAP/non-metallic PCB) to 1.227 g/cc for 60/40 (WAP/non-metallic PCB) panels. SEM images clearly show that the non-metallic glass fibres of the PCB waste were encapsulated by the plastics of the automotive waste. The homogeneous distribution and increase in interfacial adhesion between non-metallic glass fibres of the PCBs and WAP were observed. The results demonstrate that the addition of non-metallic PCB waste greatly improves the flexural, tensile and compression properties of composite panels, compared to 100% WAP panels. The flexural and tensile modulus of the 80/20 (WAP/non-metallic PCB) panel was, up by ∼50% and ∼280%, compared to 100% WAP. This sustainable and eco-friendly recycling approach provides an opportunity to utilise two problematic waste streams; complex non-metallic PCB waste and automotive plastics.

The paradox of development vs. protection and conservation of the coasts highlights the need to determine if tourism and conservation can be compatible rather than opposite activities. We analyzed the spatial and temporal changes in vegetation cover, composition and diversity in three beaches located in the state of Veracruz (Mexico) with different levels of tourism activity (Natural, Trailer Park and Hotels). We calculated tourist density and evaluated vegetation cover, species richness and diversity and analyzed the changes before and after three holiday seasons (winter, spring and summer). The Natural site had the highest vegetation cover (42.8 m2), species richness (14) and diversity (1.50), and Trailer Park the lowest (4.9 m2, 8 species, and 0.897 respectively). The BACI (Before-After-Control-Design) analysis showed no significant differences before and after the holiday seasons. Our results show how low and medium density tourism can be compatible with the protection of beach and coastal dune vegetation.

An important factor affecting the quality of furniture joints is the value of mounting forces. Most of the research to date described in the literature focuses mainly on the reaction of furniture joints to the static loads. However, there is a lack of knowledge about the properties of these joints under dynamic loading conditions. This study aimed to verify the research hypothesis that mounting forces in L-type furniture corner joints have a significant effect on the amount of energy absorbed during low speed impact. The reasons for the damaged joints and the effect of the material type and load schemes used were explained. Newly designed, innovative furniture fasteners and traditional eccentric fittings were examined. Fasteners were mounted in particleboards and medium density fiberboards. The corner joints were subjected to dynamic tension and compression loads. Appropriate numerical models were developed to simulate the response of joints to dynamic loads. As a result, it was demonstrated that the ability of connections to absorb energy significantly depends on the value of the mounting forces and the type of materials used. Furthermore, a positive correlation between the mounting forces and the stiffness and strength of these joints was confirmed.

Coastal onsite wastewater disposal systems (OWDS) were inundated by Hurricane Sandy's storm tide. This study compares the shallow groundwater quality (nutrients, pharmaceuticals, and hormones) downgradient of OWDS before and after Hurricane Sandy, where available, and establishes a baseline for wastewater influence on groundwater in coastal communities inundated by Hurricane Sandy. Nutrients and contaminants of emerging concern (CECs) were detected in shallow groundwater downgradient of OWDS in two settings along the New Jersey and New York coastlines: 1) a single, centralized OWDS in a park; and 2) multiple OWDS (cesspools) in low-density residential and mixed-use/medium density residential areas. The most frequently detected pharmaceuticals were lidocaine (40%), carbamazepine (36%), and fexofenadine, bupropion, desvenlafaxine, meprobamate, and tramadol (24-32%). Increases in the number and total concentration of pharmaceuticals after Hurricane Sandy may reflect other factors (seasonality, usage) besides inundation, and demonstrate the importance of analyzing for a wide variety of CECs in regional studies.

Fully biobased all-cellulose fibreboards are produced without the use of additional bonding agents such as polymer resins or binders as in the case of e.g. medium density fibreboard (MDF) or natural fibre reinforced plastic (NFRP). These materials make use of the self-binding capability of cellulose, exploiting the enhanced hydrogen bonded network present in micro- and nanofibrillated cellulose, resulting in good mechanical performance. After the optimisation of refinement, drying and hot-pressing conditions, binder-free panels from microfibrillated flax fibres with excellent mechanical properties of around 17 GPa and 120 MPa for flexural modulus and strength, and relatively low water sorption are achieved, making these materials competitive with conventional cellulose based composite materials. The work shows the potential of creating all-cellulose engineering materials using only the intrinsic bonding capacity of microfibrillated lignocellulose, potentially leading to environmentally friendly panel board materials, which are entirely based on renewable resources, recyclable and biodegradable.

Multi-layer Stream Mapping (MSM) comprehends a new framework for the performance assessment of complex systems. The MSM was developed for multi-domain analysis in an original manner to assess if resources, process and other domains are used to their full potential. The costs related with misuses/inefficiency situations are also quantified and integrated in a simplified manner. A real case study applying the MSM method is validated through application to a Medium Density Fibreboard (MDF) finishing line. For this study all the resources and materials consumed in each unit process where considered. The overall efficiency was assessed and improvements actions were evaluated.

The objective of this study was to reinforce particleboard products with natural bast fibers which have high tensile strength and stiffness-to-weight ratios. Three-layered particleboards were manufactured from Wood, Hurd and Shive particle furnish and reinforced in the upper and lower face layers with aligned Flax and Hemp fiber mats. Control particleboard samples were manufactured from 100% Wood, Hurd and Shive furnish for comparison purposes. Mechanical and physical strength properties were conducted according to ASTM D1037-6a and ANSI standards for medium density particleboard. Compared with 100% Wood, Hurd and Shive particleboards the bending strength properties of the fiber-reinforced particleboards were significantly (p = 0.0158, p

A vibration testing method based on free vibration theory in a “free–free” support condition was investigated for evaluating the modulus of elasticity (MOE) of full-size wood composite panels (WCPs). Vibration experiments were conducted on three types of WCPs (medium density fibreboard, particleboard, and plywood) to determine the dynamic MOE of the panels. Static bending test was performed on small specimens cut from the panels to determine the static MOE. A strong linear relationship was found between dynamic MOE of full size panels and static MOE of small specimens. Dynamic MOE of full-size WCPs was found 6.2% higher than the corresponding static MOE. This study demonstrated that free vibration method has a good potential to be used in WCP manufacturing facilities as a quality control procedure.

The Chinese mitten crab, Eriocheir sinensis (H. Milne Edwards), is an important economic aquaculture species in China. It is very popular within Chinese consumers for the abundant nutrition and delicious taste. It has been widely cultured and had great yield recently; yet, the short available time of E. sinensis cannot satisfy consumers’ increasing demanding. Thus the overwintering cultivation of E. sinensis has become one problem to urgently await development. Aiming to find the optimal stocking density and time for overwintering rearing E. sinensis using net cages embedded in a circulating pond aquaculture system, in the present study, we analyzed the variations in growth performance, death rate, physiological status, and nutrient contents of E. sinensis at different stocking densities over time periods. The death rate increased significantly after rearing for 90 days, while medium stocking density had a slight advantage than other densities. Interestingly, E. sinensis had no significant weight loss during overwintering period regardless of stocking densities. Our findings suggested that the optimal stocking density is around 21.88 kg/m2 in case of overwintering cultivation less than 90 days; while a medium density of 15.63 kg/m2 is more suitable for longer term overwintering cultivation (more than 90 days). In any case, the optimal overwintering rearing of E. sinensis should not beyond the 2rd, April. We can barely found difference caused by stocking density in activity of digestive enzymes, antioxidant status, or gene expression of hsp70; however, their levels were fluctuant over rearing time. Moreover, we found no significant variation in muscular amino acids composition, but a rising ratio of PUFA/SFA, as well as increased levels of C20:4 and C20:5 in edible tissues after 105-days overwintering cultivation, suggesting an improved nutritional value and eating quality of E. sinensis. Our results provide a reference standard for the overwintering cultivation of E. sinensis. Keywords: Eriocheir sinensis, Stocking density, Cumulative survival rate, Fatty acids, Antioxidant status

The pyrolysis model in FDS6 is applied to simulate a series of small-scale tunnel experiments under varied forced ventilation velocities, where cribs made of medium density fireboard (MDF) are used as the fuel source. Prior to the simulations the material properties of MDF are investigated in order to effectively describe the decomposition behaviour in FDS6 and to develop optimised values. In the tunnel simulations, the effect of the burning duration of the ignition source, the heat of combustion of the MDF in the presence of the forced ventilation, the assumed fuel mass and the modelling domain set-up on the prediction of heat release rate are examined. It is found that the cribs take longer to ignite than that in the experiment; the available burning mass is affected by the assumed thickness of the crib sticks and the available surface area; and a limited domain size can result in not all of the fuel burning. Efforts are made to obtain an equivalent burning mass to the experiments and to account for the influence of the forced ventilation on the burning efficiency by manually specifying the heat of combustion to improve the predictions of heat release rate and consumption of fuel mass.

A study was conducted to test the mechanical properties of medium density fiberboard (MDF) produced using soybean straw [Glycine max], wheat straw [Triticum aestivum], and a blend of the two fibers and the variations in properties that this blend produced. Additionally, the difference of soybean straw fibers compared to wheat straw fibers in the performance of MDF properties was investigated. Three formulations of the fibers were produced and tested to investigate the variation between properties of boards produced from the different fibers. The boards produced for testing were pressed using a hot press with 4 wt% methylene diphenyl diisocyanate (MDI) resin used to bond the particles and 2 wt% AW-50 wax emulsion used as a water retardant. The boards produced had a nominal density ranging from 579 kg/m3 to 646 kg/m3. Several test methods from ASTM standard D1037-12 were utilized to test the physical and mechanical properties of the boards. Initial results from the testing showed that several combinations of fibers could be used to produce boards with mostly no statistically significant difference between any one formulation, the only difference being a significantly higher difference in the screw withdrawal load needed for 100% wheat fiberboards compared to other formulations. The testing showed the viability of soybean stover fibers as a viable substitute or blend with wheat straw fibers with no appreciable decrease in the board properties except in the case of direct screw withdrawal resistance.

A three-dimensional numerical model (the Model for Urban Surface Temperature – MUST) was used to investigate the impact of urban geometry on average urban albedo and street surface temperature. Satisfactory performance of the model in predicting urban albedo was confirmed. The calculated results for different canyon geometries show that: 1) the medium density urban condition (plan area index λ p = 0.44) absorbs the most solar radiation and thus has the lowest urban average albedo; 2) the average urban albedo decreases with increasing building height; and 3) in general, more solar radiation is absorbed as building height differences become much greater. Therefore, the average urban albedo is the least for a medium density city having high-rise buildings with greater building height differences. The relationship between sky-view factor and street surface temperature was also examined. The model predicted a cooler urban street surface temperature with a smaller daily amplitude and earlier occurrence of the daily maximum temperature for a high-rise high density city when compared to a low-rise low density city. Horizontal surfaces in an urban area play an important role in determining the average urban albedo. A linear relationship was found between the average sky-view factor of horizontal surfaces and the average urban albedo.

Dense medium drum (DMD) separators are unit processes that are typically used to beneficiate coal, iron ore and other minerals by making use of density separation. Some coal dense medium separation plants typically include a DMD separator. The operational management of this unit process is often limited to localised control of medium density and feed mass flow rate. Dynamic models for coal dense medium separation have been developed by the authors with the intention of using them for dynamic control. A suitable dynamic model for a DMD separator could not been found in the available literature. This paper shows how the dynamic model for a dense medium cyclone has been applied to a DMD separator. The model parameters were determined and the performance of the model is evaluated using actual plant data from a Wemco drum. Coal washability and drum partitioning behaviour are used to estimate the grade of the product for model grade simulation and validation.

Medium Density Fiberboard (MDF) has been one of the most rapidly growing composite panel products to enter world market in recent years. Optimization of drilling parameters for Medium Density Fiberboard (MDF) panel with multiple performance characteristics using Grey Relational Analysis (GRA) method was done. Drilling parameters, such as feed rate, spindle speed, drill diameters were considered for the study. By analyzing grey grade matrix, the degree of influence for each controllable process factor on to individual targets can be found. An optimal parameter combination of drilling operation was obtained via GRA. The feed rate was identified to be the most influencing factor on surface roughness and delamination. Additionally, ANOVA (Analysis of Variance) is used to find the interaction between parameters and the possible error in the experiments

The in-plane shear modulus (IPSM) of medium-density fibreboard (MDF) was obtained via a torsional vibration (TV) test using the specimen with various configurations and a subsequent numerical analysis. Because the out-of-plane shear modulus (OPSM) of MDF was much lower than the IPSM, the difference between the IPSM and OPSM had to be considered in the TV test. Therefore, the OPSM value was measured from the flexural vibration (FV) tests, and it was applied for the calculation of the IPSM value. The experimental and numerical results indicated that the TV test is effective to obtain the IPSM of MDF accurately under various configurations of the specimen.

In the manufacturing of medium density and high density fiberboards the fiber characteristics and mat density substantially influence mat permeability, compaction pressure and panel's physicomechanical properties. In this paper, the permeability and compaction response of kenaf bast fiber mats are experimentally determined at three fiber lengths for both dry and resinated fiber mats with various levels of mat densification. The mats of long fibers have demonstrated higher permeability and require higher compaction pressure than short fiber mats at the same level of densification. Furthermore, kenaf panels in the density range of 800 kg/m3 to 1100 kg/m3 are manufactured with commercial melamine urea formaldehyde resin and three fiber categories. The panels are evaluated to demonstrate the effects of these factors on a panel's physicomechanical properties. The higher compaction pressure and good stress distribution with long fibers have resulted in higher mechanical properties than those of short fiber panels. On the other hand, a decrease in fiber length has lowered the mat permeability, resulting in significant improvements in dimensional properties. The panel physicomechanical properties can also significantly improve by increasing the panel density. The high density kenaf panels have shown excellent mechanical properties which are well above the standard requirements of MDF and HDF panels according to ( ANSI, A208.2: 2009 ) and ( ANSI, A135.4-2012 ) standards.

Over the next few years, thermal energy for heating residential buildings will be reduced, while cooling energy will be increasingly used. Therefore reversible heat pumps producing heating and cooling energy efficiently may become more popular in areas with mild climate. The Ground Source Heat Pump (GSHP) system is one of the most promising techniques which can be coupled with other solutions based on renewable energy. The present work considers a heating and cooling district based on a closed loop GSHP and its energetic and economic aspects, including the density of population in the district where the buildings are located. Economic analysis and payback times are investigated as a function of inhabitant density, adopted solutions, as well as different economical benefit scenarios. Primary energy consumption may be reduced in a range of 50–80%, compared to traditional systems. The district heating/cooling is more suitable in a medium density area and splitting a district into sub-district distribution systems may reduce the initial financial risk. Possible mechanisms for the diffusion of GSHP are here shown for district heating/cooling systems. Policy makers and stakeholders may use the results of this work for promoting possible incentives, which can be similar to the ones presented here.

Panel mass and nitrogen losses indicate medium density fibreboard (MDF) panels bonded with differing urea formaldehyde (UF) resins readily lose some 40–70% of resin components on exposure to cold water soaking. Analysis reveals these labile extractable resin components to be low molecular weight UF oligomers which were not present in such amounts in the original UF resins. Panel emissions appear linked to the relative proportions of these extractable UF resin condensation products. Furthermore, results indicate that when applying resin to fibre, resin components may chromatographically separate and become unavailable to cross-link into a fully cured resin matrix. Differences in wood fibre extractives, resin chemistry or application methodology gave minor differences in extractable resin components, but a greater resin loading contributed to lower relative resin extractability.

The development of Medium Density Fibreboard (MDF) made from renewable biomass of pineapple (Ananas comosus) leaf fibre and their suitability as a construction material has been investigated. Two different types of board with a target density of 0.8 gr/cm3 were manufactured. The board was prepared in three layers of about 1:1:1 weight ratio in unidirectional and cross-oriented board using low molecular weight (LM) PF resin type PL-3725 and high molecular weight (HM) PF resin type PL-2818 for impregnation and adhesive purposes. For comparison, boards with the same structure were prepared using high molecular weight PF resin only. The biological properties of the boards have been examined as their termite resistance against subterranean termite attack. The results indicate that there was a significant effect of impregnation with low molecular weight PF resin on the susceptibility of the MDF board specimens. The results also show that fiber orientation had no significant effect on the termite resistance of the specimens against Coptotermes formosanus Shiraki. The Type PF resins were significant for termite mortalities of the tested property. The total resin content of 20% of the board type prohibits the degradation by termites.

Mechanical properties of sports surfaces have previously been shown to be influenced by surface drainage, moisture content and compaction but these factors have not yet been quantified for equestrian surfaces. The aim of the study was to examine the effect of three moisture levels (11.96 ± 1.63%, 17.31 ± 1.14%, 19.08 ± 0.78%) and three rates of compaction (1.647±0.02 g/cm3, 1.748±0.046 g/cm3, 1.766±0.039 g/cm3) on the functional properties of a synthetic equestrian surface constructed over two distinct drainage profiles. The surfaces with a high (19.08%) moisture content and medium density when laid on permavoid™ had the most favourable results when taking into account all of the measured parameters with regards to reducing the risk of injury yet potentially offering sufficient support to the horse for efficient locomotion.

Urban traffic system plays a decisive role in structuring urban morphology. Sustainable traffic network can not only promote urban structure optimization, but also can achieve sustainable urban transformation (UT). Xi’an, one of the most important central cities in Western China, is selected as the research area. This research analyzes the change of traffic network in the process of UT by using road network density, road network connectivity and traffic service capability indexes to quantify the development of traffic during different period. The results shows that these three indexes are improved by 72.7%, 58.3% and 33.3% respectively after starting UT. (1) After starting UT, the expansion speed of high road network density area was far than speed before. The medium density area spread to the surrounding counties to form the network. (2) High road connectivity areas expanded rapidly and extended to the north and south, while the areas with low value area had not been effectively developed. (3) High traffic service capability area gradually aggregated, mainly extended to south and central of Xi’an We conclude that urban transformation has a positive effect on changes of urban traffic network, and urban traffic network also can promote sustainable urban transformation.

Blending satellite-based precipitation estimation (SPE) data and in-situ gauge observation data can generate effective spatially-continuous-precipitation estimates with improved accuracy. This study assessed the improvement of the long-term SPE when blending with in-situ gauge observations for drought monitoring, using a simple but effective blending method named the geographical difference analysis (GDA) method and with the Precipitation Estimation from Remote Sensed Information by using Artificial Neural Networks-Climate Data Records (PERSIANN-CDR) as case study. In-situ precipitation observations from three meteorological station sets with different densities—the sparse (50), medium (200), dense (727) station set—were adopted to evaluate the effect of gauge density on the performance of SPE-gauge data blending. Two widely-used indices—standardized precipitation index (SPI) and self-calibrating Palmer drought severity index (SC_PDSI)—were used as case studies. Except the case of sparse 50-station subset, the SPE-gauge blending shows apparent improvement to the raw PERSIANN-CDR data, for both the accuracy of precipitation input and many aspects of drought monitoring, e.g. reproducing drought magnitude and revealing spatial pattern of drought, in which SC_PDSI shows more significant improvement than SPI. The dense 727-station set shows the largest improvement in the blending data, but the corresponding station-only interpolations also exhibit comparable performance to the blending data, indicating lower utilization value of the SPE data for these cases. Only the blending results of the medium-density 200-station set shows satisfactory drought monitoring performance as well as significant improvements relative to the station-only interpolations. According to the quantitative analyses, the medium density (about 50–75 gauges per 106 km2 in our cases) might be the most economic gauge density for SPE-gauge blending, as it has satisfactory improvement in blending results, can make fullest use of the advantages of SPE data and requires relatively fewer gauges. Our results can help to understand how the SPE-gauge blending could improve the SPE-based drought monitoring and serves as a reference for applying drought monitoring under the data-limited conditions. Subsequent studies or applications should also carefully consider the effect of gauge density.

The objective of this work was to evaluate surface quality of wood based materials used to manufacture furniture units in Singapore. Various type commercially produced composite panels including particleboard, medium density fibreboard (MDF), plywood in addition to ten different solid wood species which are commonly used in furniture production were considered for the experiments. A stylus type profilometer and 3D image analyzer were employed to determine surface roughness of the samples. Medium density fibreboard (MDF) samples resulted in the smoothest surface with an across the sandmark average roughness ( R a ) value of 5.07 μm, while corresponding value for plywood specimens was 8.09 μm among the composite panel samples. In the case of solid wood samples, measurements taken along and across the sandmark from the surface of the specimens measured by the stylus type profilometer, balau had the roughest surface with an R a value of 9.85 μm across the sandmark followed by beech and walnut. Pine specimens along with ash, cherry and nyatoh resulted in relatively smooth surface values. Correlation between measurements taken by two different methods, namely stylus and 3D scanning showed a good agreement with each other. Based on the findings in this work it appears that both methods can be successfully used to evaluate and to get objective numerical values on surface quality of these samples so that such initial data can be used as quality control tool to have more effective further manufacturing steps in furniture production.

In previous simulations lane-changing behavior is usually assumed as an instantaneous action. However, in real traffic, lane changing is a continuing process which can seriously affect the following cars. In this paper, a microscopic lane-changing process (LCP) model is clearly described. A new idea of simplifying the lane-changing process to the car-following framework is presented by controlling fictitious cars. To verify the model, the results of flow, lane-changing frequency, and single-car velocity are extracted from experimental observations and are compared with corresponding simulation. It is found that the LCP model agrees well with actual traffic flow and lane-changing behaviors may induce a 12%–18% reduction of traffic flow. The results also reflect that most of the drivers on the two roads in a city are conservative but not aggressive to change lanes. Investigation of lane-changing frequency shows that the largest lane-changing frequency occurs at a medium density range from 15 vehs km − 1 lane − 1 to 35 vehs km − 1 lane − 1 . It also implies that the lane-changing process might strengthen velocity variation at medium density and weaken velocity variation at high density. It is hoped that the idea of this study may be helpful to promote the modeling and simulation study of traffic flow.

Many offshore structures are subjected to overturning moments due to wind load, wave pressure, and ship impacts. Also most of retaining walls are subjected to horizontal forces and bending moments, these forces are due to earth pressure. For foundations in such structures, usually a combination of vertical and batter piles is used. Little information is available in the literature about estimating the capacity of piles under uplift. In cases where these supporting piles are not vertical, the behavior under axial pullout is not well established. In order to delineate the significant variables affecting the ultimate uplift shaft resistance of batter pile in dry sand, a testing program comprising 62 pullout tests was conducted. The tests are conducted on model steel pile installed in loose, medium, and dense sand to an embedded depth ratio, L/d, vary from 7.5 to 30 and with various batter angles of 0°, 10°, 20°, and 30°. Results indicate that the pullout capacity of a batter pile constructed in dense and/or medium density sand increases with the increase of batter angle attains maximum value and then decreases, the maximum value of Pα occurs at batter angle approximately equal to 20°, and it is about 21–31% more than the vertical pile capacity, while the pullout capacity for batter pile that constructed in loose sand decreases with the increase of pile inclination. The results also indicated that the circular pile is more resistant to pullout forces than the square and rectangular pile shape. The rough model piles tested is experienced 18–75% increase in capacity compared with the smooth model piles. The suggested relations for the pullout capacity of batter pile regarding the vertical pile capacity are well predicted.

Face stability is critical for ground settlement and construction safety control in shield tunneling. In this paper, a series of 3D large-scale model tests with a tunnel of 1 m diameter were conducted in dry sand for various cover-to-diameter ratios C / D = 0.5, 1, and 2 (i.e., relative depth; C is the cover depth and D is the diameter of tunnel). Each test provided a measurement of the support pressure and the ground settlement with the advance of face displacement. The evolution of soil arching during face failure was investigated by monitoring the redistribution of earth pressure in front of the face in the test case of C / D = 2. In the displacement-controlled face failure tests in the medium density sands, the support pressure dropped steeply to the minimum value, then increased to a steady state with the continuing increase in the face displacement. Relationships between the support pressure and face displacement for various cover depths were also verified by the numerical analysis using the finite difference program, FLAC 3D ( Itasca, 2005 ). The limit support pressure increases with the increase of the relative depth C / D and then tends to be constant. A significant rotation of principal stress axes in the upward arches in the soil during face failure was found in the tests. A two-stage failure pattern is proposed based on the observation of earth pressure. The theoretical and empirical formulas for estimating limit support pressure were verified by the tests results.

The field emission (FE) properties of carbon nanotubes (CNTs) films with different morphologies were simulated and examined. Based on the FE mechanism of aligned CNTs’ emitter the theoretical analysis exhibited the following relations: the FE enhancement factor with the distance between the emitters, the electric field with work function, and the work function with FE enhancement factor. Using the structure-induced CNTs growing method and theoretical results the direction of aligned CNTs could be controlled and the special morphology with different aligned CNTs’ film could be fabricated. Comparing to the experimental results (the medium density and patterned CNTs’ emitters) with the theoretically calculating results the I–V curves had the same trend with only 0.05 mA deviation. Based on the better experimental methods and means the accurate of formula could be further improved by modified the FE properties (Φ, β).

Site-specific weed management implies detecting the location of weeds in order to generate maps of their spatial distribution. This information facilitates a more accurate application of herbicides, spraying them in the exact areas of weed growth and in the required doses. In order to explore the potential of commercial satellites to discriminate and map weeds, we used the information contained in high spatial resolution images acquired by the QuickBird satellite to assess the density of sterile oat ( Avena sterilis ) present in a winter barley field at two different dates (March and June). Our results confirmed the potential of using satellite images in the spectral discrimination of weed patches in infested fields. The results of binary logistic regressions showed that the best matches in the classification of three categories (low, medium, or high sterile oat densities) corresponded to the March image. QuickBird’s March image provided reliable estimates of sterile oat patches in barley crops when weed density was relatively high (between 86% and 94% of agreement between predicted and observed densities). However, when weed densities were lower than 10 plants/m 2 there were serious difficulties to distinguish them from weed-free zones (between 72 and 75% of global agreement in the classification) with large underestimation of medium density weed patches (10 plants/m 2 ). This is a potential limitation considering than the thresholds used for herbicide application decisions are generally close to this density. However, the information obtained may still be useful for producing field maps to describe the spatial distribution of this weed. Moreover, these studies have provided valuable information on the best spectral regions and/or vegetation indices for approaching discrimination between sterile oat and cereal crops and the most suitable period for it.

In this research, new hybrid medium density fibreboard (MDF) was produced by using rubberwood (RW) and empty fruit bunch (EFB) based on oven-dried weight. There are two different ratios of hybrid MDF from rubberwood and EFB were produced which are EFB:RW, 20:80 and EFB:RW, 50:50 at 65% and 93% relative humidity (RH). The effect of storage time and relative humidity on the mechanical and physical properties of new hybrid MDF was studied. It was found that at 93% relative humidity, new hybrid MDF exhibited a highest effect on the mechanical and physical properties of panel after 10 weeks storage time. It observed that, hybrid MDF with ratio of EFB:RW, 20:80 exhibited the highest mechanical (flexure test and internal bonding) and physical properties [moisture content (MC), thickness swelling (TS), water absorption (WA)] as compared to hybrid MDF produced from EFB:RW, 50:50. Thus, the result showed that addition of higher amount of EFB fibres in hybrid MDF will decreased the composites properties. The property of composites decreases with increase of relative humidity and storage time. The result showed that, at 65% humidity new hybrid MDF exhibited lower effect on mechanical and physical properties of the panel.

Volatile organic compounds (VOCs) emitted from building and furnishing materials are frequently observed in high concentrations in indoor air. Nondestructive analytical methods that determine the main parameters influencing concentration of the chemical substances are necessary to screen for sources of VOC emissions. Toward this goal, we have developed a new flux sampler, referred to herein as an emission cell for simultaneous multi-sampling (ECSMS), that is used for screening indoor emission sources of VOCs and for determining the emission rates of these sources. Because the ECSMS is based on passive sampling, it can be easily used on-site at a low cost. Among VOCs, low-molecular-weight carbonyl compounds including formaldehyde are frequently detected at high concentrations in indoor environments. In this study, we determined the reliability of the ECSMS for the collection of formaldehyde and other carbonyl compounds emitted from wood-based composites of medium density fiberboards and particleboards. We then used emission rates determined by the ECSMS to predict airborne concentrations of formaldehyde emitted from a bookshelf in a large chamber, and these data were compared to formaldehyde concentrations that were acquired simultaneously by means of an active sampling method. The values obtained from the two methods were quite similar, suggesting that ECSMS measurement is an effective method for screening primary sources influencing indoor concentrations of formaldehyde.

Introduction Acuros-XB (AXB) algorithm has been introduced several years ago in order to improve the accuracy of dose calculation in radiotherapy, especially in the presence of tissue heterogeneities. This type (c) algorithm is based on the deterministic resolution of the linear Boltzmann transport equation and offers results close to Monte Carlo simulations. This study aims to evaluate the clinical impact of a new algorithm by comparing the dosimetric and radiobiological results of the AXB algorithm for its two reporting modes (dose to water AXB-Dw and dose to medium AXB-Dm), compared to a reference algorithm: the Anisotropic Analytical Algorithm (AAA). Methods Ten cases of patients treated for lung cancer with conformational radiotherapy were studied. For each patient, five treatment plans were generated. The dose in plans 1, 2 and 3 was respectively calculated with AAA, AXB(Dm) and AXB(Dw), using the same prescribed dose (PD). In plans 4 and 5, the dose was calculated using the two AXB calculation modes with the same number of monitor units (MU) derived from the AAA calculation (plan 1). The dosimetric evaluation was based on the comparison of dose volume histograms (HDV) and quality metrics (i.e. Conformity, Coverage and Homogeneity indices). Radiobiological assessment was based on the comparison of tumor control probabilities (TCP) and toxicity probabilities (NTCP) for organs at risk (OARs), including lungs, esophagus and heart. Wilcoxon and Spearman’s rank tests were used to calculate p-values and the correlation coefficient (ρ). Results Using the same PD, we observed a significant increase in the number of MU (1–4%), depending on the choice of AXB-Dm or AXB-Dw. In dosimetric terms, dose calculated with AXB is more heterogeneous. This introduces a significant decrease in the minimum dose to the PTV and in the quality indices. These elements can influence the therapeutic results. In addition, the dose to OARs was increased from +2% to +10%. The increase in dose to target volumes and OARs with AXB, using the same PD, explains the increase in TCP (+1% to 2%) and in NTCP (+2%) (p Conclusions AXB algorithm is known to provide improved calculation accuracy. However, a special attention is required in order to safely implement its clinical use. Depending on the medium density, the technique and the treatment field size, MU can increase as well as the dosimetric values and the NTCPs. Radiation oncologists and medical physicists should define together the attitude to be adopted regarding these dosimetric shifts. A reasonable approach would be to keep the same PD while increasing the sparing of the OARs.

Reasons of the strength loss of the acetylated wood based composites were still under question. This research was considered to study springback in the acetylated particleboard and the medium density fibreboard. Chips and fibres were acetylated by using the acetic anhydride to gain different percentages of the weights (WPG). The boards were made based on the target thicknesses. Thickness of the boards as well as the modulus of elasticity (MOE) and the modulus of rupture (MOR) were determined after conditioning based on three point static bending test. Results showed that the moisture content and the thickness swelling of the boards were reduced as the WPG was increased. However, increase of the springback and reduction of the MOE and the MOR were revealed as the WPG increased in the test boards after condition. It was also revealed that the springback was correlated with the weight gain and increased as the WPG was raised in the test boards. Reduction of the MOE and the MOR was also correlated with the springback in the test boards.

Medium density fibreboard (MDF) is an engineering wood product. This material is appropriate for many common and industrial applications. The aim of this article is to study of the cutting parameters (cutting speed and feed rate) on delamination in MDF drilling. A plan of two MDF panels drilling experiments was performed drilling with prefixed cutting parameters. The objective was to establish correlation between cutting speed and feed rate with the delamination around the MDF hole. The delamination factor decreases with the increase of cutting speed and increases with the feed rate for both materials. The drill tests showed the different scheme of delamination for each material of coating layer (wood or melamine).

We have observed the Cygnus Loop from the northeast (NE) to the southwest (SW) with XMM-Newton. We extracted spectra from 3′-spaced annular regions across the Loop and fitted them either with a one-kTe-component non-equilibrium ionization (NEI) model or with two-kTe-component NEI model. We found that the two-kTe-component model yields significantly better fits in almost all the spectra than the one-kTe-component model. Judging from the abundances, the high-kTe-component in the two-temperature model must be fossil ejecta while the low-kTe-component comes from the swept-up interstellar medium (ISM). The distributions of Ne, Mg, Si, and S for fossil ejecta appear to retain the onion-skin structure at the time of a supernova explosion, suggesting that significant overturning of the ejecta has not occurred yet. Comparing the relative abundances of fossil ejecta estimated for the entire Cygnus Loop with those from theoretical calculations for Type-II SN, the mass of the progenitor star is likely to be ∼13 M⊙. The trends of the radial profiles of kTe and emission integral for the swept-up ISM are adequately described by the Sedov model, suggesting that the swept-up ISM is concentrated in a shell-like structure. Comparing our data with the Sedov model, we found the ambient medium density to be ∼0.7 cm−3. Then, we estimated the total mass of the swept-up ISM and the age of the remnant to be ∼130 M⊙ and 13,000 years, respectively. Note that if the explosion occurred within a stellar wind cavity, then the density in the cavity, the total swept-up mass in the cavity, and the age of the remnant are estimated to be ∼0.14 cm−3, ∼25 M⊙, and ∼10,000 years, respectively.

This paper presents the methodology of Taguchi optimization method for simultaneous minimization of delamination factor at entry and exit of the holes in drilling of SUPERPAN DECOR (melamine coating layer) MDF panel. The delamination in drilling of MDF affects the aesthetical aspect of the final product and hence it is essential to select the best combination values of the drilling process parameters to minimize it. The utility concept has been employed for the multi-performance characteristics optimization using Taguchi design. The experiments were carried out as per L 9 orthogonal array with each experiment performed under different conditions of feed rate and cutting speed. The analysis of means (ANOM) was performed to determine the optimal levels of the parameters and the analysis of variance (ANOVA) was employed to identify the level of importance of the machining parameters on delamination factor. The investigations revealed that the delamination can be effectively reduced in drilling of MDF materials by employing the higher cutting speed and lower feed rate values.