Resin Distribution in Medium Density Fiberboard. Quantification of UF Resin Distribution on Blowline-and Dry-Blended MDF Fiber and Panels

A novel technique has been developed for visualizing urea formaldehyde (UF) resin distribution on fibers and within MDF panels. A fluorescent label was chemically bound to the resin, and digital images of resinated fiber, generated via confocal laser scanning microscopy (CLSM), were analyzed. Results indicate that this technique can be used to quantify UF resin coverage and distribution as well as provide information on resin film thickness on MDF fiber before pressing and in panels. The technique can distinguish between different methods of resination and was employed to determine that these processes can result in different surface coverages of UF resin on MDF fiber. Resin injected at the end of the blowline gave significantly less resin coverage of fiber than that which was injected at the start of the blowline. UF resin droplets were also relatively thicker and less dispersed when injected at the end of the blowline. Visualization of UF resin also illustrated resin distribution changes upon pressing of fiber particularly in the presence of wax. This result has important implications for future studies targeting optimization of resin deposition, since the droplet size distribution, as applied to the fiber, may not correspond to the droplet size distribution of resin in the panel

Reliability Assessment of the Nigerian Timber – An Environmental Sustainability Approach in the 21st Century

An important component of environmental sustainability is how we can continue improving human welfare within the limits of the earth’s natural resources. With recent research showing that carbondioxide levels in the air are at their highest in 650,000 years and thus an alarming depletion of the ozone layer, the challenge currently facing many countries is how to respond to the issue of climate change. Steel, reinforced concrete and timber are the most commonly used structural materials worldwide. However, carbondioxide emissions from steel and cement production have been found to be the first and second largest sources of industrial C�� emissions worldwide and this has prompted the inclination towards timber as a structural material. Timber is decomposable or biodegradable as well as renewable and its production does not require the use of high energy fossil fuels as in the production of some other building materials such as steel or even brick. Nigeria is blessed with several timber species in different wood classes but despite the environmentally sustainable and obvious advantages of timber, it is being grossly underutilized as a structural material in Nigeria because there is limited information on the reliability of timber considering the wide property variability between and even within, timber species. This paper addresses the need for reliability analysis of various Nigerian timber species with a view to determining and establishing their structural strength to encourage the use of the Nigerian Timber as a structural material. The need to revise the Nigerian Code of Practice for the structural design of Timber is also emphasized in this pape

“Четвертий поділ” Польщі і встановлення радянського тоталітарного режиму в Західній Україні

The present article was based on the unknown documents of the Branch state archive of Security service of Ukraine and showed the first phase so called “sovietizashion” (establishment of Soviet regim) of Western Ukraine after being joined to the USSR in the September 1939. The author investigeted the measures used to arrange the 800-meter borderland between the USSR and Third Reich

Mechanical properties of high strength eco-concrete containing crushed waste clay brick aggregates as replacement for sand

Utilization of clay brick wastes for production of high strength eco-concrete enables the combat of raw resources depletion due to excessive mining as well as mitigating environmental pollution caused by demolition of old brick structures in an effort to achieve environmental sustainability in line with the sustainable development goals (SDGs). This study investigates the beneficial usage of crushed clay brick as partial replacement for natural sand in producing high strength eco-friendly concrete. The replacement percentages of the crushed clay brick in respect to sand are 0, 10, 20, 30, 40 and 50% by weight using a mix proportion ratio of 1:1:2 at a constant water-cement ratio of 0.25, aiming at the 28 days compressive strength of about 40 MPa. The chemical characterization of the crushed clay brick and cement was conducted via X-ray fluorescence (XRF). The mechanical properties tests were performed on about 80 specimens using 100 x 100 x 100 mm for cubes, 100 x 100 x 500 mm for beams and 100 x 200 mm diameter for cylinders after 7, 14 and 28 days of curing in water. Results showed that concrete containing crushed clay brick as partial replacement for sand compare favourably well with the control. Consequently, it is suggested that generated clay brick wastes can be crushed and used as replacement for natural sand for the production of eco-friendly high strength concrete