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Polymers for Artificial Joints
Published in Severian Dumitriu, Valentin Popa, Polymeric Biomaterials, 2020
Masayuki Kyomoto, Toru Moro, Kazuhiko Ishihara
Total hip arthroplasty (THA) or hemi-arthroplasty is a surgical procedure whereby the diseased cartilage and the bone of the hip joint are surgically replaced with an artificial joint to restore joint movement (Figure 25.1). In general, total hip joint replacement consists of three (cement fixation) or four (cementless fixation) parts as follows: A plastic cup and metal shell that replaces the hip socket (acetabulum)A metal or ceramic ball that replaces the fractured femoral headA femoral metal stem that is attached to the shaft of the bone to add stability to the prosthesis If a hemi-arthroplasty is performed, either the femoral head or the hip socket (acetabulum) will be replaced with a prosthetic device.
Ill Environmental Issues and Packaging Design
Published in Susan E. M. Selke, Packaging and the Environment, 1994
For example, switching from a foamed polystyrene cup to one made of paper may well result in a public perception of an environmentally beneficial action. If the cup is destined for a landfill, the short range effects on solid waste generation are likely to be minimal at best. Though the paper cup will degrade eventually, this “eventually” may well be many decades. Other effects of the decision may be increased water pollution from the papermaking process, formation of dioxins from the bleaching process, and soil erosion and nutrient depletion from growing and harvesting trees. The growth of the trees, on the other hand, may have resulted in removal of carbon dioxide from the atmosphere, ameliorating the greenhouse effect. Use of fossil fuels may have been reduced by the switch to a nonpetroleum based raw material or may have actually increased due to the use of fossil fuels in growing and harvesting the trees and making, converting, and transporting the paper. Only a detailed energy analysis will show which is the case. Finally, if recycling the cup is an option, the plastic cup is likely to be much easier to recycle than the paper cup, which requires either a wax or plastic coating to function properly.
Determining Properties of Materials
Published in Dale Ensminger, Leonard J. Bond, Ultrasonics, 2011
Dale Ensminger, Leonard J. Bond
The ultrasonic diffraction grating was formed by machining triangular grooves with a periodicity of 483 μm on the flat surface of an aluminum unit with send and receive transducers fastened to it. The unit has a height of 3.81 cm. A plastic cup contains the slurry, in contact with the grating surface. The ultrasonic beam from the send transducer A strikes the back of the grating at an incident angle of 30°, and the reflected beam travels to receive transducer B. Beams of various transmitted orders m are also transmitted into the slurry, where m = 0, ±1, ±2, and so on. The attenuation is focused on the m = 1 transmitted beam that increases in angle, relative to a normal to the grating surface, as the frequency of the beam decreases. The frequency where it reaches 90° is called the critical frequency. At this transition point, the transmitted beam becomes evanescent and interacts with the particles in the slurry, reducing the amplitude of the wave. Essentially, an evanescent wave is one that travels in a direction parallel to the grating surface, but its amplitude decreases exponentially with the distance from the grating surface. Slightly below the critical frequency, the existence of an m = 1 transmitted beam is no longer possible. The energy is transferred to other beams, such as the m = 0 reflected beam, which is observed by the receive transducer. Thus, a peak is expected to be observed by the receive transducer at the critical frequency. The height of this peak depends upon the particle size since the interaction of the evanescent with the particle also depends upon particle size.
Preparation of temperature-sensitive slow-release snowmelt agent by UV-irradiation grafting method
Published in Road Materials and Pavement Design, 2023
ShengYue Wang, DanNi Guo, RuPeng Tian
The permeation performance can indirectly reflect the slow-release performance of the snowmelt agent. A transparent plastic cup was taken and treated at the bottom, 10 g of TSSA was added for shaking and levelling. 200 mL of distilled water was poured along the wall of the cup and then recorded the permeation time. The filtrate was also tested for conductivity using a conductivity metre (DDS-307). The basic experimental setup is shown in Figure 4. Here, the ability to transport electrons in a solution or other electrolyte was defined as conductivity. This meant that the more ions the solution contains, the better the ability to transfer electrons is. So higher conductivity meant that more effective snowmelt agent was dissolved in the solution (Liu et al., 2015). The conductivity test was based on the idea that the snowmelt agent components could be considered as electrolytes, and therefore the conductivity value of the filtrate or post-soak solution could represent the amount of that snowmelt agent released (Liu et al., 1999). The control group was a mixture of 20 g of Mafilon (named MFL) and 20 g of only four mixed salts added to the powder under the same conditions. The permeation time and filtrate conductivity values were recorded separately.
Assessment of autochthonous aquatic macrophytes with phytoremediation potential for dairy wastewater treatment in floating constructed wetlands
Published in International Journal of Phytoremediation, 2020
Rita de Cássia Souza de Queiroz, Ivon Pinheiro Lôbo, Vinícius de Souza Ribeiro, Luciano Brito Rodrigues, José Adolfo de Almeida Neto
On the other hand, despite the reduction of up to 65.1% of TS on D4, from D6 on, a considerable increase in TS was observed, which can be attributed to the physical structure of the platform. The PET-bottle platform allowed dead leaves shed by the macrophytes to return directly to the system, consequently increasing the organic matter contents in the wetlands. Lagos et al. (2009) observed similar behavior for BOD rates, which increased after the fall of the Eichhornia crassipes leaf during treatment of the kraft mill effluent. However, Ladislas et al. (2015) and Winston et al. (2013) employed floating mats equipped with either a type of plastic cup or holes for the attachment of the aquatic macrophytes. The fallen leaves were deposited on these mats, forming a new natural environment above the wastewater surface.
Particle dispersion analysis in an 11-row Boeing 767 cabin mockup
Published in Science and Technology for the Built Environment, 2019
An injection system directing pressurized air into a plastic cup holding a fixed amount of powder was built. The release of compressed occurred over a short period of time to better represent a sneeze and to form a puff of particles. The pressurized air was released from a tank of fixed volume charged to 400 kPa (60 psi) gauge pressure. A solenoid valve was controlled to open for 15 ms. This short period of time insured local release of powder particles and maintained the uniformity of the cabin to ensure that it was not disturbed by the injection process. The pressurized air was directed into the cup holding the powder samples, forming a cloud of powder around the nasal zone area of a seated passenger at a height of 25 cm from the lap of a seated person, as shown in Figure 2a.