Marine Plywood Research Articles

Impact of Formwork Materials on Concrete Surface Quality

Given the functional and aesthetic quality expected from concrete surfaces, this study investigated the influence of different formwork materials on their surface density, porosity, voids, and elementary chemical composition by relying on X-ray Microtomography (μCT), Scanning Electronic Microscopy (SEM), and Energy Dispersive X-ray Spectroscopy (EDS). The formwork materials assessed were galvanized steel, regular plywood (pink), marine plywood, polyvinyl chloride (PVC), and silicone. μCT showed that distinct formwork affected the surface density of the concrete. In this case, specimens cast within silicone and marine plywood had similar pore volumes although different pore sizes, whereas PVC led to the highest pore volume with small pore sizes. Galvanized steel and regular plywood resulted in similar porosity. SEM showed that the concrete surfaces produced with marine plywood formwork had the highest void content. EDS identified surface products resulting from the contact of concrete with the different formwork materials, suggesting the potential migration of chemical elements. This research significantly contributes to optimizing formwork material selection and enhancing concrete quality and durability. Moreover, it establishes a foundation for further investigations into how formwork materials affect concrete surfaces and the pathological manifestations potentially arising from the molding process.

Sunflower Stalk ASH: Prime Additive to Latex Paint for Fire Retardancy of Marine Plywood

This research study investigates the use of sunflower stalk ash as a prime additive to latex paint for the fire retardancy of marine plywood. Its main goal was to assess the effectiveness of sunflower stalk ash paint in improving the fire retardancy of marine plywood. The researchers employed a simplified flame spread test to determine the effectiveness of the paint, and statistical analysis alongside observation were used to ascertain the ideal concentration required for the sunflower stalk ash paint. The findings revealed that the use of sunflower stalk ash paint can significantly improve the fire retardancy of marine plywood, with the most effective outcome observed in marine plywood that was coated thrice with 16% concentration of sunflower stalk ash in latex paint. This study suggests that utilizing agricultural waste like sunflower stalk ash could serve as an effective and efficient method for enhancing the fire retardancy of marine plywood.

Properties Enhancement of Oil Palm Trunk Plywood against Decay and Termite for Marine Applications.

Oil palm trunk (OPT) veneers have the potential to be used in the production of plywood for marine applications. However, OPT is not resistant to fungal decay and termites, limiting its use in the production of marine plywood. As a result, in this study, phenolic resin treatment was used to improve the biological durability of OPT and produce marine grade equivalent (MGE) plywood. The OPT veneer was treated with medium molecular weight phenol formaldehyde (MmwPF) resin. The results showed that MmwPF resin with a solid content of 30% resulted in higher weight percent gain and polymer retention. Veneers treated with 30% MmwPF resin were then pressed for more than 10 min at temperatures above 140 °C. Dimensional stability, shear strength, bending strength, fungal decay resistance, and termite resistance were all tested on the plywood produced. The results of this study revealed that MGE plywood has satisfactory bonding quality and excellent biological durability. Good bending strength was recorded for the MGE plywood with modulus of rupture and modulus of elasticity ranged between 31.03 and 38.85 MPa and 4110 and 5120 MPa, respectively. Rubberwood, as a reference sample in this study, is not durable (Class 5) against white rot fungi and is moderately durable (Class III) against subterranean termite attacks. Interestingly, MGE plywood produced in this study was found very durable (Class 1) against white rot fungi. It is also durable (Class II) and very durable (Class I) against termite attacks, depending on the pressing parameters employed. Based on their outstanding bonding quality, bending strength, and biological durability, the study confirmed the feasibility of OPT plywood for marine applications.

Biological Resistance of Acetylated Radiata Pine, European Beech, and MDF against Marine Borers at Three Italian Sites after Five Years Immersion

The aim of this research was to determine the resistance of acetylated wood against marine biodeterioration in use class 5 for use in temperate waters. The resistance of acetylated radiata pine (Pinus radiata D. Don) on solid and medium-density fiberboard (MDF) panels was compared with untreated wood of European species, such as European beech (Fagus sylvatica L.), sweet chestnut (Castanea sativa Mill.), European oak (Quercus robur L.), and marine plywood. As a reference control, untreated Scots pine (Pinus sylvestris L.) sapwood was used. The field tests were carried out in accordance with EN 275, and started in April 2015. The three Italian exposure sites were Marine of Scarlino private harbor, Port of Genoa, and the Venice Lagoon. Final evaluation in 2021 showed a greater resistance to marine borers of acetylated wood, radiata pine, and beech and MDF panels. However, the untreated European species showed low resistance against marine organisms, with complete decay after the first year of exposure.

Resistance of fibreboards made of milled coconut husk and bonded with tannin against insects and fungi under Philippine conditions

ABSTRACTThe study is aimed to determine the resistance of fibreboards made of milled coconut (Cocos nucifera [L.]) husk and bonded with tannin adhesive (Coconut Fibreboards - CFB) against wood-destroying insects and fungi under laboratory and field conditions. Marine plywood (MPW) samples were included in the tests for comparison. Results showed that CFB had higher resistance to insect and fungi than MPW. After four months of laboratory exposure to subterranean termites CFB had only few signs of nibbling with weight losses of 3.5%. MPW showed instead weight losses of 95%. CFB exposed for 12 months to drywood termite were damaged between 0.0% and 6.0%. MPW damage was within 21.0% and 65.0% within the same period. Wood decay fungi caused weight loss of 7.8% in CFB, while weight losses between 55.4% and 88.0% were observed in MPW. The potential of CFB for applications as ceiling and wall cladding in the Philippines was therefore suggested.

Using FEM simulation to predict structural performances of a sailing dinghy

The use of finite element method (FEM) tools is proposed to investigate the structural response of an eco-sustainable sailing yacht to different loading conditions, typical of those acting during regattas. The boat is, in particular, a 4.60 m dinghy with the hull and the deck made of an hybrid flax–cork sandwich and internal reinforcements made of marine plywood. A preliminary activity has consisted in the refitting of an existing model in order to reduce the hull weight and to improve performances during manoeuvrings. These tasks have been interactively simulated in the virtual environment of the boat CAD model, where longitudinal and transversal reinforcements were enlightened and the maximum beam reduced. At the same time, results of FEM simulations on the modified model were analysed in order to verify the structural integrity. Shape modifications have been applied to the real model in laboratory and the resulting hull has been instrumented with strain gauges and tested under rigging conditions to validate the numerical procedure. Finally, the FEM model was used to predict the response of the boat to loading systems typical of sailing conditions.

Evaluation of Smoke Density on Combustion of Wood Based Panel Products

Smoke density of wood based panel materials like General purpose plywood, Marine Plywood(BWP grade), Medium Density Fibre Board (MDF), Bamboo Mat Board (BMB), Pre-laminated Particle Board (PPB) were measured using chamber method (ASTM D 2843-70). The specimens are tested inside closed chamber and readings of light transmission were taken at 5-seconds interval. Measurements were made in terms of loss of light transmittance through an accumulated volume of smoke. It was observed that pre-laminated particle board and general purpose plywood with 22.20% &22.47% of smoke accumulation area respectively resulted lower values as compared to other panel products such as marine plywood (BWP grade), MDF, BMB etc. A uniform rate of smoke build-up was recorded. This study provides the basis for predicting the smoke production rate, time to ignite (TTI), and Toxicity index which can be developed by combustion of the wood product.

Influence of the reuse of OSB and marine plywood formworks on concrete surface aesthetics

Concrete surface quality is becoming increasingly important because demand for a high level of aesthetics has spread across a wide variety of construction works. Even though it is difficult to clearly define what represents “beauty” in construction materials, existing techniques may be used to quantify the aesthetic properties of concrete. As these properties depend mainly on the type of formwork used, this research project focuses on the reuse of two types of panel—plywood and OSB—and two types of release agent—vegetable oil and mineral oil. The evolution of the surface properties of the concrete was measured through lightness and absorption. For plywood formworks, a modification of surface quality was noticed after 80 reuses; for OSB panels, such changes were observed after only 50 reuses. For both types of formwork, the choice of release oil did not seem to have a major influence on formwork absorption. It was also observed that alkalis caused early degradation of the panels: the release agents were not always effective in avoiding this phenomenon. Finally, although reuse was found not to have any influence on the absorption capacity of the plywood formworks studied, this was not the case for the OSB formworks.

The “Silver Hut” Expedition— A Commentary 40 Years Later

The “Silver Hut” Expedition— A Commentary 40 Years Later

Attachment Strength of Zebra Mussels on Natural, Polymeric, and Metallic Materials

Zebra mussel ( Dreissena polymorpha and D. bugensis ) fouling has increased operating and maintenance costs for marine and industrial facilities. An understanding of zebra mussel attachment strength on various substrates of different surface roughness is useful for the development of control strategies. Mussel attachment strength was inferred directly through tensile loading experiments using a calibrated force scale, and indirectly through fluid detachment using a wall jet. The results of both techniques were consistent and yielded statistically significant differences for different substrate types (natural ≥ metallic > polymeric). Attachment varied significantly with material ( P < 0.01) and with surface roughness within a material ( P < 0.05). The lowest attachment strengths were measured on (in increasing order of attachment strength) smooth polytetrafluoroethylene, polymethylmethacrylate, and aluminum. The strongest attachment was measured on rough limestone/dolomite cobble, and mild steel of all roughnesses. Zebra mussel attachment strength was intermediate on, marine concrete, marine plywood, polyvinylchloride, stainless steel, and coal tar epoxy coated mild steel. These results provide preliminary design guidelines for the control of zebra mussels.

AN IMPROVED STRESSED-SKIN SUPPORT FOR ARTWORKS ON CANVAS OR PAPER

AN IMPROVED STRESSED-SKIN SUPPORT FOR ARTWORKS ON CANVAS OR PAPER

Toxic Effects of Marine Plywood

To the Editor.— I read with interest the recent article regarding toxic effects from burning arsenic-treated (pressure-treated) wood. 1 I recently had a bulkhead installed using such wood. Discussion with the builders indicated that they suffered from rough and irritated hands and had irritation of other parts of their body that were routinely in contact with the wood during construction. They usually did not wear gloves. This is clearly an effect of the chemicals contained in the wood, most notably arsenic, and is not usually seen in carpenters not using arsenic-treated wood. The effects may be accentuated in marine construction use, with the recent introduction of 1.13-kg treated wood. This wood has ten times the amount of chemicals found in the usual 0.11-kg pressure-treated wood used in land construction, the type most likely burned by the family in the aforementioned article. I suggest that appropriate warnings be distributed to lumber

Toxic effects of marine plywood

Toxic effects of marine plywood

Seasonal Arsenic Exposure From Burning Chromium-Copper-Arsenate-Treated Wood

All eight members of a rural Wisconsin family experienced recurring neurological and medical illness over three years, especially during the winter months. Arsenic, in concentrations of 12 to 87 ppm, was noted in the hair of the mother and father, and analysis of hair and fingernails of all family members demonstrated pathological levels of arsenic. For four years the five-room home had been heated with a small wood stove in which outdoor or marine plywood and wood remnants had been preferentially burned. Stove ashes that contained more than 1,000 ppm of arsenic contaminated the living area, and the ratio of copper, chromium, and arsenic pentoxide in this ash matched the ratio used in the chromium-copper-arsenate-treated wood.

Design and Operation of a Small Two-Boat Purse Seine

A small purse seine, 250 ft. long and 23 ft. deep, and two 14 ft. purse boats to fish it in shallow estuaries for menhaden (Brevoortia) are described. The seine is made of No. 6 nylon in the two wings and heavier No. 15 nylon in the center bunt. Mesh is 1 3/8 in. bar. Purse boats have a 7 ft. beam and 2 ft. of freeboard, and are built of 1/4 in. marine plywood and seasoned oak ribs. A 40 hp outboard motor mounted in a center well powers each boat. Boats and seine are portable (on trailers) and can be used any place where launching sites are available. Over 40,000 menhaden were caught and marked with internal ferro-magnetic tags over a 3-year period. Boats and seine also could be used to capture other schooling species.

Sculpture: Science Fiction Machines

On 19 June 1974, Granada's television programme 'Granada Reports' contained a review of the John Moore Exhibition at Liverpool and on the next evening's programme there was an item on one entitled 'The Even Moore', a cocky salon des refuses, organized by Peter O'Halligan (Dream Merchant), that opened in Liverpool on the 11th June. It was in the latter exhibition that my 'Pandora's Box' was first shown. Granada's reporter described it as a sculpture for people who eat chickens. A little girl called Dawn, no more than two years old, visited the exhibiton each day, climbing up the stairs from the shop below where her mother worked, just to watch and listen to my chickens. 'Pandora's Box' (Fig. 1) is a sinister-looking dark wooden chest with a wooden moulding at top and bottom. The construction consists of a strong wooden frame covered with marine plywood sheet in order to give the impression of a strong solid piece of furniture. At the top of the front face is a small door with a brass lock and at the bottom of the rear face is an ominous thick electric cable that curls away to a small black box on a 3 ft. stand. In this box is played a tape recording of the noise made by lots of real chickens. (Some thought that I had recorded the sounds made at a

A Portable Observation Chamber for the Study of Fish Behavior

Abstract A portable observation chamber used in the study of fish behavior in the natural environment is described. The chamber, containing two observation windows, is constructed of marine plywood attached to a supporting framework. Adjustable pipe legs permitted observation at various heights either above water or under water.