Styrofoam Beads Research Articles

Designing and testing the applicability of a natural green ventilation building block in an Egyptian Climatic zone using waste materials

Natural ventilation is one of the ways used to enhance building spaces' indoor air quality, especially after the COVID-19 pandemic. It also saves energy by utilizing natural wind forces to provide internal building spaces with fresh air instead of energy-consuming mechanical systems. For a multiple-floor building, adding external wall ventilation blocks can improve natural cross ventilation by catching and directing fresh air from the external prevailing wind into its internal spaces. This research aimed to enhance the building's natural ventilation by using environmentally friendly blocks. This was done by designing a green block using marble and granite waste materials as a partial substitute for conventional materials in the block. Styrofoam beads were added to the block’s mixture to reduce its weight. The block’s shape was designed to direct fresh air through building side walls by the use of natural wind pressure. The block was developed from the initial shape of the standard hollow block to a block with a wind catcher. Ventilation block shape simulations were done using (ANSYS fluent) computational fluid dynamics (CFD) software to determine the best inlet angle, catcher angle, and catcher length. The study revealed that by increasing the block inlet angle more than 45°, the block outlet air velocity starts to decrease due to the flow separation in the front part of the block inlet. The catcher angle ranged from 65° to 85°, and the catcher’s ability to redirect the airflow is decreased at a catcher angle greater than 85°. The best nondimensional catcher length-to-block length ratio (height /length) h/L was 0.625. Substitution of 5% of cement by granite in the presence of 0.15 Kg of Styrofoam (C5G) produced a lightweight green ventilation block of weight 19.3 kg. Whereas, the substitution of 15% of sand for marble in the presence of 1 Kg of Styrofoam (S15M) produced a lightweight green ventilation block of weight 15.9 kg. The produced block was tested in a building located in New Cairo City (a region currently having a tremendous increase in the building construction sector) as a study sample representing one of the Egyptian Climatic zones. The research concluded that it is preferred to allocate the building corners towards the prevailing wind direction to prevent airflow separation and to magnify the quantities of air along the building sides.

Kidney stone pushing and trapping using focused ultrasound beams of different structure

A technology to reposition kidney stones with radiation force was recently proposed by our team and already used to transcutaneously facilitate passage of small stones. While successful, the trial revealed a need for optimization of the ultrasound beam structure, frequency, and intensity to make it more effective. In the current work, the effect of the ultrasonic beam diameter vs. stone size using a quasi-Gaussian beam model was numerically investigated. Radiation force on a kidney stone was found to be strongest when the beam width was slightly wider than the stone diameter. This can be explained by more effective generation of shear waves inside the stone resulting from their effective coupling with the acoustic waves in liquid at the stone edges. In another study, the possibility of using vortex beams to trap the stones in the lateral direction was investigated. Both theoretical modeling and experiments were performed using two systems: a single-element transducer combined with a sector-shaped phase plate and a 12-element sector array. Human stones approximately 3-5 mm, as well as glass and styrofoam beads, were controllably translated along the surface transverse to the beam. [This work was supported by RBBR 14-02-00426, NIH NIDDK DK43881, DK104854, and DK092197, and NSBRI through NASA NCC 9-58.]

Frame-Based Immobilization and Targeting for Stereotactic Body Radiation Therapy

Frame-based stereotactic body radiation therapy (SBRT), such as that conducted with Elekta’s Stereotactic Body Frame, can provide an extra measure of precision in the delivery of radiation to extracranial targets, and facilitates secure patient immobilization. In this paper, we review the steps involved in optimal use of an extra-cranial immobilization device for SBRT treatments. Our approach to using frame-based SBRT consists of 4 steps: patient immobilization, tumor and organ motion control, treatment/planning correlation, and daily targeting with pretreatment quality assurance. Patient immobilization was achieved with the Vac-Loc bag, which uses styrofoam beads to conform to the patient’s shape comfortably within the body frame. Organ and motion control was assessed under fluoroscopy and controlled via a frame-mounted abdominal pressure plate. The compression screw was tightened until the diaphragmatic excursion range was < 1 cm. Treatment planning was performed using the Philips Pinnacle 6.2b system. In this treatment process, a 20 to 30 noncoplanar beam arrangement was initially selected and an inverse beam weight optimization algorithm was applied. Those beams with low beam weights were removed, leaving a manageable number of beams for treatment delivery. After planning, daily targeting using computed tomography (CT) to verify x-, y-, and z-coordinates of the treatment isocenter were used as a measure of quality assurance. We found our daily setup variation typically averaged < 5 mm in all directions, which is comparable to other published studies on Stereotactic Body Frame. Treatment time ranged from 30 to 45 minutes. Results demonstrate that patients have experienced high rates of local control with acceptable rates of severe side effects—by virtue of the tightly constrained treatment fields. The body frame facilitated comfortable patient positioning and quality assurance checks of the tumor, in relation to another set of independent set of coordinates defined by the body frame fiducials. The ability to impose abdominal compression proved to be a simple way to reduce target and tissue motion. SBRT with Stereotactic Body Frame enables comfortable patient immobilization and facilitates repeated registering and re-registering of the patient to the frame. With the body frame, large-dose-per fraction treatment is possible for localized tumor deposits with the aim of attaining a more therapeutic result.

Study of density and stability of a lung-equivalent gel

Gel dosimetry is a useful tool for the verification of radiation treatments in water-equivalent tissues. In order to extend the application of gel dosimetry to the lung, the density of the dosimeter should be reduced. Some methods have been proposed for the fabrication of low-density gels. Major challengesin the fabrication of these gel dosimeters are to achieve a density that equals the electron-density of lung tissue and to obtain an acceptable homogeneity. Both polymer and Fricke gel formulations have been used as basic chemical compositions for low-density gel dosimeters. To reduce the density, two approaches have been suggested: (1) Styrofoam beads can be added to the gel or (2) the gel can be beaten until a foam is obtained. In this study we followed the latter method andadded sodium-dodecyl-sulphate (SDS) as a surfactant to increase the surface tension of the gel.

SU‐FF‐J‐53: Effect of Tumor Motion On the Use of PET Images for Target Volume Delineation in Radiation Treatment Planning

Purpose: To assess the effect of both motion and medium heterogeneity on automatic PET target delineation fused with CT images for radiation treatment planning of lung tumors. Method and Materials: The data were acquired on Philips Gemini PET‐CT scanner. A movable lung phantom was built using the NEMA IEC body phantom containing 6 hollow spheres with diameters ranging from 10 to 37 mm. The phantom volume was packed with Styrofoam beads and filled with water to reach the density close to the density of lung 0.3g/cc. The tumor motion was simulated by a movable acrylic table that provided variable amplitudes and frequencies of movement to the phantom. The spheres were filled with 1.14 mCi/ml of FDG. There was no background activity in the body phantom outside of the spheres. Scans were performed for variable amplitudes ranging from 0.5 to 2 cm. CT and PET images were auto‐contoured on Pinnacle workstation using variable thresholds relative to the maximum SUV. The threshold that best measured the volume of each sphere in static mode and the effective volume in dynamic mode was assessed. Results: The SUV threshold that best defines the target volume in static mode and the effective volume in dynamic mode when no respiratory gating is applied depends on the motion amplitude. The small spheres are more sensitive to the inhomogeneity of the medium, most probably because the positron range is greater in lung equivalent medium then in water. Conclusions: The study shows that it is not accurate to apply a constant threshold for target volume delineation in radiation therapy for all tumor sizes and variable tumor movement. The change of target delineation threshold is more due to the increase of the partial volume effect when the tumor activity is spread over a large volume proportional to the magnitude of movement.

Organic Matter and Hydraulic Loading Effects on Nitrification Performance in Fixed Film Biofilters with Different Filter Media

Nitrification performance of fixed film biofilters using coarse sand, loess bead, or styrofoam beads in biofilter columns 1 meter high and 30cm in diameter were studied at different hydraulic and organic matter loading rates. Synthetic wastewater was supplied to the culture tank in order to maintain desired TAN concentrations in inlet water to biofilters. All the biofilters were conditioned 5 months before start of sampling. TAN and conversion rates increased with an increase in the hydraulic loading rate (HLR). However, the improvement in biofilter performance was not linearly correlated to HLR in styrofoam bead filters. This is mainly due to the characteristics of the styrofoam beads used. TAN conversion rates of sand filters increased with the increase of HLR up to . per day. No increase in the TAN conversion rate was observed at the highest HLR since flooding on the media surface took place. HLR had a significant impact on the TAN conversion rates in loess bead filter up to the highest HLR tested (P per day than those without the addition of organic matter in styrofoam bead filters. The addition of glucose resulted in a reduction of the TAN conversion rate from 540 to 284g per day. No significant difference of TAN conversion rates between the two organic matter loading rates was found (p. per day, a great reduction of TAN conversion rates was observed in sand filters and loess bead filters. Clearly, organic matter can be one of the most Important Impacting factors on nitrification. conversion rates showed a similar trend for TAN. Based on the TAN and nitrite conversion rates, styrofoam beads showed the best performance among the three filter media tested. Also, the low gravity and price of styrofoam beads make the handling easier and more cost-effective for commercial application. The results obtained at the highest organic matter loading rates can be used in the biofilter design in recirculating aquaculture system.

Wearable Force Display Using a Particle Mechanical Constraint

A particle mechanical constraint (PMC) is a soft vinyl tube containing Styrofoam beads. It can be freely compressed, elongated, bent, twisted, or otherwise manipulated in all degrees of freedom. Evacuation of the air inside the tube makes the PMC rigid so that it maintains whatever shape it has been given. The stiffness of the PMC is proportional to the reduction in internal pressure below atmospheric pressure. Viscosity is also controlled virtually by changing the inside air pressure in proportion to the speed of transformation of the PMC. We used a PMC to develop a wearable force display that provides the sensation of coming into contact with a wall or of moving in water with viscosity, in addition to that of moving in air. PMC is an inherently passive device that never exerts excessive force if it were to malfunction. In short, it is suitable as a wearable human interface because it is light, soft, and safe.

Quantitative cardiac SPECT in three dimensions: validation by experimental phantom studies

A mathematical framework for quantitative SPECT (single photon emission computed tomography) reconstruction of the heart is presented. An efficient simultaneous compensation approach to the reconstruction task is described. The implementation of the approach on a digital computer is delineated. The approach was validated by experimental data acquired from chest phantoms. The phantoms consisted of a cylindrical elliptical tank of Plexiglass, a cardiac insert made of Plexiglass, a spine insert of packed bone meal and lung inserts made of styrofoam beads alone. Water bags were added to simulate different body characteristics. Comparison between the quantitative reconstruction and the conventional FBP (filtered backprojection) method was performed. The FBP reconstruction had a poor quantitative accuracy and varied for different body configurations. Significant improvement in reconstruction accuracy by the quantitative approach was demonstrated with a moderate computing time on a currently available desktop computer. Furthermore, the quantitative reconstruction was robust for different body characteristics. Therefore, the quantitative approach has the potential for clinical use.

Evapotranspiration in Tidal Marshes

Field experiments were completed to determine patterns of evapotranspirative water loss from salt and tidal freshwater marshes in Virginia. Water losses from “Mariotte systems” attached to open-water lysimeters and lysimeters vegetated by dominant marsh macrophytes were used to calculate hourly rates of open-water evaporation (Eo) and evapotranspiration (ET), respectively, during low tide. In the tidal freshwater marsh, ET was significantly greater than Eo (p=0.002, n=6); in the salt marsh, there were no differences between mean rates of ET and Eo (p=0.200, n=3). The ratio ET:Eo was highly correlated with leaf area index (LAI) (r2=0.82). In the tidal freshwater marsh, the amount of water loss due to plant transpiration was partitioned from total evapotranspiration by covering the water surface of the lysimeters with styrofoam beads. Measured transpiration rates in the tidal freshwater marsh were strongly correlated with leaf area index according to the following linear regression equation: T=0.355(LAI)−0.084 (r2=0.797, n=10). Because LAI was shown to be a good predictor of the relative increase in ET over Eo, it is likely that in vegetated tidal freshwater marshes with high leaf densities most atmospheric water loss comes from plants, not from the surface of the marsh. In salt marshes, low plant densities do not contribute substantially to atmospheric water loss, suggesting that paths of water transport and patterns of solute concentration in the subsurface environment are different compard to the tidal freshwater marsh.

Vacuum-stiffened beanbag for cranial remodeling procedures in modified prone position. Technical note.

In surgical correction of multiple-suture synostosis, placing the patient in the modified prone position permits access to the calvarium from the supraorbital ridge to the occipital bone below the transverse sinus. The modified prone position thereby enables surgeons to perform cranial remodeling procedures at one stage under direct vision, contributing to improved surgical results. However, no satisfactory head-frame for this position has been available. The authors report the successful use of a vinyl bag filled with styrofoam beads to achieve the modified prone position in young children. This widely available, economical device provides a safe, reliable means of positioning the child's head for cranial remodeling procedures.