Masonry Sand Research Articles

Educational high school physics demonstration apparatus for acoustic landmine simulant resonance detection

This landmine “simulant” resonance detection demo was created in conjunction with a high school physics mentorship, using a variety of easily-accessibleequipment in order to demonstrate an important application of fundamental concepts of sound and vibration. A plastic tray (4 in. deep) contained a 3-in. diameter drum-like circular landmine simulant (1.5 in. high) with a thin acrylic top plate buried (1 in. deep) in a 3 in. layer of dry sifted masonry sand. A small accelerometer was place on the surface over the simulant. Airborne sound, a loud speaker chirp, with frequency slowly increasing over time, was created using a Mathematica® generated wav file played by the Raspberry Pi® computer. Sound excited the sand vibration that coupled to the top plate. The accelerometer generated a frequency response voltage, related to the sweep time. The Raspberry Pi® also played a role in implementing the A to D conversion, so that the frequency response near resonance was displayed as a voltage in a readable format. With this demo apparatus high school students will be excited by the fundamentals of wave propagation and concepts about resonance with regards to its real-life applications. [Specially inspired by James M. Sabatier’s research on acoustic landmine detection.]

Green-Building-Index-Assessment-Criteria-Based Comparative Evaluation of Interlocking Blocks as an Alternative to Conventional Masonry for Residential Buildings in Malaysia

Major residential construction projects adopt clay bricks as masonry, which can contribute to high carbon emission, primarily due to their high embodied carbon. Furthermore, the adoption of conventional masonry, including clay bricks, may lead to the use of high amounts of mortar and contribute to a lot of wastage. Therefore, an alternative system that can potentially replace conventional masonry is required to reduce the wastage as well as carbon emission. Interlocking blocks, which adopt a lock and key system has the potential to replace conventional masonry as they employ locally available materials, save construction time, use less mortar and are less dependent on highly skilled masons. In view of their potential, the adoption of interlocking blocks in residential buildings were evaluated comparatively to conventional masonry, namely clay and cement sand bricks, based on the Green Building Index Assessment Criteria for Residential New Construction (GBI-RNC) tool. Overall Thermal Transfer Values of test models that employed conventional masonry and interlocking blocks were calculated. Approximately, based on the GBI-RNC tool, with an increase of 17-18 points achieved from the EE, MR and IN criteria, a Silver rating can be achieved with the adoption of interlocking blocks.

Comparison of dry or wetted sand column vibrating over a clamped elastic plate: A nonlinear sand-plate-oscillator

The sand plate oscillator apparatus uses two aluminum circular flanges sandwiching and clamping a thin circular elastic acrylic plate (density 1.21 g/cc). Dry sifted or wetted masonry sand is supported at the bottom by the clamped acrylic plate (4.5 in.) and stiff cylindrical sidewalls. Sifted masonry sand has a density of 1.55 g/cc. An accelerometer centered on the plate measures vibration response using a swept tone spectrum analyzer between 50 and 850 Hz. The plate was driven from below by a small loudspeaker. Three experiments were performed. (1) Nonlinear tuning curve response required driving the loudspeaker and incrementing the signal amplitude between sweeps. A fixed column of 354 g of dry masonry sand was used, with comparisons when 0, 11, 22, and 33 g of water were carefully sprayed on. (2) At constant drive amplitude, tuning curve response with 354 g of dry sifted sand was compared with results when 2 g of water were sprayed every 104 s. (3) Fixed drive amplitude tuning curves for incremental dry sand loading with 47 g for each layer were compared to incremental layers of 47g dry sand sprayed with 12 g water. The wetted sand had increased stiffness.

Yellow nutsedge (Cyperus esculentus) interference in simulated sweetpotato plant beds

AbstractGreenhouse experiments were conducted in 2016 at Pontotoc and Verona, MS. On March 3 (Pontotoc) and March 7 (Verona), landscape fabric was placed in the bottom of polyethylene lugs, each 0.22 m2, then approximately 5 cm of a 1:1 (v/v) blend of soilless potting media and masonry sand was added. ‘Beauregard’ sweetpotato [Ipomoea batatas(L). Lam.] storage roots weighing between 85 and 227 g, and several with emerging sprouts ≤1 cm, were placed longitudinally in a single layer on the substrate, then covered with an additional 3 cm of the substrate. Sprouted yellow nutsedge (Cyperus esculentusL.) tubers were transplanted equidistantly into sweetpotato-containing lugs at six densities: 0, 18, 36, 73, 109, and 145 m−2. Trials were terminated 55 and 60 d after planting at Pontotoc and Verona, respectively. Predicted total sweetpotato stem cuttings (slips) decreased linearly from 399 to 312 m−2asC. esculentusdensity increased from 0 to 145 m−2. Predicted total slip dry weight at aC. esculentusdensity of 145 m−2was reduced 21% compared with 0 m−2. Predicted rotten sweetpotato storage roots increased from 2.6 to 11.3 m−2asC. esculentusdensity increased from 0 to 145 m−2. In response to increasingC. esculentusdensity, sweetpotato seed roots exhibited increased proximal-end dominance.

Nonlinear tuning curve demonstration: Comparing a buried mine simulant with a clamped elastic plate—Cylindrical soil column oscillator

Experiments using soil-plate-oscillators (SPO) involve a cylindrical column of granular media (masonry sand) supported by a clamped circular elastic acrylic plate (12.7 cm diameter, 3.2 mm thick). The plate is clamped between two 20.3 cm O.D., 12.7 cm I.D., 6.4 cm thick flat toroidal brass “rings.” Two 15 cm diameter subwoofers (10 cm above the soil) are driven by an amplified swept sinusoidal chirp which drives the 2.5-cm soil column. A spectrum analyzer measures the laser Doppler vibrometer particle velocity versus frequency near the center of the column. The resonant frequency decreases with the increasing amplitude—representing softening in the nonlinear system. The back-bone curve (locus of the resonant frequency versus corresponding peak velocity coordinates) has a distinct arching shape where the slope of the velocity increases with the decreasing frequency. Here, the resonant frequency goes from 247 to 203 Hz. A lumped element bilinear hysteresis model describes the shape of the tuning curves and backbone curve. Next, a drum-like simulant (made by replacing the upper toroidal ring by a 0.64-cm thick ring) is buried 2.5-cm deep in an open square concrete tank (57 cm). Nonlinear tuning curve experiments “on” and “off” the mine are compared with the SPO results. Experiments using soil-plate-oscillators (SPO) involve a cylindrical column of granular media (masonry sand) supported by a clamped circular elastic acrylic plate (12.7 cm diameter, 3.2 mm thick). The plate is clamped between two 20.3 cm O.D., 12.7 cm I.D., 6.4 cm thick flat toroidal brass “rings.” Two 15 cm diameter subwoofers (10 cm above the soil) are driven by an amplified swept sinusoidal chirp which drives the 2.5-cm soil column. A spectrum analyzer measures the laser Doppler vibrometer particle velocity versus frequency near the center of the column. The resonant frequency decreases with the increasing amplitude—representing softening in the nonlinear system. The back-bone curve (locus of the resonant frequency versus corresponding peak velocity coordinates) has a distinct arching shape where the slope of the velocity increases with the decreasing frequency. Here, the resonant frequency goes from 247 to 203 Hz. A lumped element bilinear hysteresis model describes the shape of the tuning curves and ...

Experiments in linear and nonlinear acoustic landmine detection

When nonmetallic land mines are difficult to detect using ground penetrating radar, acoustic landmine detection is used as a confirmation sensor. Non-metallic mines include VS 1.6 and VS 2.2 anti-tank plastic landmines. In modeling nonlinear acoustic landmine detection, a 20 cm diam drum-like landmine simulant (5.08 cm height, 0.64 cm thick aluminum bottom, 0.64 cm thick acrylic top plate) was used. The flexural vibration of the acrylic top plate with the soil behaves nonlinearly. A concrete soil tank filled with dry sifted masonry sand served as an idealized granular medium. The soil tank was 57.2 × 57.2 × 22.9 cm deep (wall thickness 15.2 cm). The simulant is 3 cm deep. In airborne excitation experiments, two 8 inch diam subwoofers radiate a swept tone. A geophone (1 inch diam) measured the rms particle velocity at 28 scan locations across a 56 cm segment on the surface. The geophone-microphone frequency response (between 50 Hz and 450 Hz) vs. scan position is used to extract a response profile at any individual frequency. The lowest drum-like mode shape was strongest at 156 Hz. Nonlinear tuning curve measurements at fixed locations exhibit more softening “on the mine” vs. “off the mine.”

Demonstration of acoustic landmine detection using a clamped soil plate oscillator with airborne sound excitation

Landmine detection in gravel road beds, soil, or sand for some mines (constructed out of plastic) are difficult to detect using ground penetrating radar. In acoustic landmine detection, one would like to remotely detect a vibration profile across the surface of the soil (sand or gravel) due to the interaction between a large soil column and the localized elastic top plate. In an idealized laboratory experiment, the soil plate oscillator (SPO) apparatus models an idealization of an acoustic landmine detection experiment. The clamped circular acrylic plate (1/8 in. thick) models the top plate of a plastic buried mine while the soil column (350 g dry sifted masonry sand) supported by the plate models the burial depth. A constant current amplified sinusoidal chirp from a sweep spectrum analyzer drives two three inch diam speakers (placed above the column) generating airborne excitation. A laser Doppler vibrometer (LDV) measured the rms particle velocity at 15 scan locations across the 4.5 inch diameter soil surface in sweeps between 50 Hz and 1250 Hz. The LDV-microphone frequency response vs. scan position is used to extract a response profile at any individual frequency. These mixed mode shapes are compared for both in-phase and out-of-phase excitation.

Effect of Soil Carbon on Phytotoxicity of Topramezone-treated Irrigation Water to St. Augustinegrass

Topramezone is a 4-hydroxyphenylpyruvate dioxygenase (HPPD)-inhibiting herbicide that was labeled for aquatic use in Florida in 2013 with a maximum submersed application concentration of 50 µg·L−1. Preliminary greenhouse studies reported that the concentration of herbicide that reduces growth by 10% compared with untreated controls (EC10) of topramezone in irrigation water applied to st. augustinegrass (Stenotaphrum secundatum) grown in 100% sand was 3.5 ppb. The objective of these experiments was to determine whether substrate carbon content influenced the response of ‘Palmetto’ st. augustinegrass to irrigation with topramezone-treated water. The herbicide was applied at concentrations ranging from 0 to 120 ppb to mature plants grown in 7.5-inch-diameter nursery containers. Pots were filled with washed masonry sand amended with one of five carbon contents: 0%, 0.3%, 0.6%, 1.5%, and 4.0%. Plants were irrigated twice weekly for 4 weeks with topramezone-containing water and grown out for 12 weeks after the final topramezone treatment to evaluate possible recovery from any herbicide damage. Plant material was clipped as needed for a total of eight harvests and each harvest was dried and weighed. EC10 values for ‘Palmetto’ st. augustinegrass grown in substrates with 0%, 0.3%, 0.6%, 1.5%, and 4.0% carbon were 3.7, 7.3, 10.1, 28.1, and 25.7 ppb, respectively. These experiments revealed that substrate carbon content has a noteworthy effect on the susceptibility of ‘Palmetto’ st. augustinegrass to topramezone in irrigation water. However, regular irrigation with water containing high concentrations of topramezone is likely to cause damage to ‘Palmetto’ st. augustinegrass in Florida's sandy soils.

Modeling nonlinear acoustic landmine detection using a soil plate oscillator apparatus

In modeling nonlinear acoustic landmine detection, there will be a cylindrical drum-like buried target. This target, which has a clamped thin elastic plate, rigid sidewalls, and bottom plate, is buried in an open concrete “soil tank” containing dry sifted masonry sand. Subwoofers located 40 cm above the surface are driven with a swept tone from 50 to 450 Hz to generate airborne sound that couples into the sand exciting vibration in the buried target. A small geophone is used to measure the “ground” vibration profile across the buried target. Nonlinear tuning curves of vibration particle velocity vs. frequency are used to compare “over—off the target” results. The backbone curves (peak velocity vs. corresponding resonant frequency) are different in these cases—such that resonances due to soil alone or soil over a compliant buried target can be distinguished. Next, a soil plate oscillator SPO (consisting of two circular flanges sandwiching and clamping a thin circular elastic plate that supports a cylindrical level column of sand above the plate) is driven by airborne sound. Nonlinear tuning curve vibration at points across the sand are compared with the results in the “idealized” landmine detection experiment to develop a lumped element model of the system.

Demonstration of nonlinear tuning curve vibration of granular medium supported by a clamped circular elastic plate using a soil plate oscillator

A demonstration will be conducted in order to show how a soil plate oscillator (SPO) filled with granular material will create a nonlinear system due to shifting peaks in a tuning curve with incremental increases in the swept drive amplitude. An SPO has two flanges clamping an elastic plate which supports a circular column of granular material. The plate (with a magnet and accelerometer fastened to the underside) is driven below by an amplified swept sinusoidal current applied to an AC coil. Past results have used masonry sand, granular edible uncooked materials, and glass beads in order to study the nonlinear tuning curve response near a resonance with (1) a fixed soil column while changing drive amplitude and (2) mass loading of a soil column versus the resonant frequency response of the system at a fixed drive amplitude. When the experiments are performed at a fixed drive but with a changing mass layer the resonant frequency increases then decreases with increased added mass due to an increase in flexural rigidity of the granular media disk layer which dominates the effect of adding mass. SPO tuning curves resemble the nonlinear mesoscopic elastic behavior of resonant effects of geomaterials such as sandstone.

The soil plate oscillator: Measuring nonlinear mesoscopic elasticity of granular medium in flexural vibration

The soil plate oscillator apparatus (SPO) consists of two circular flanges (5 inch ID, 8 inch OD, 2.5 inch thick) sandwiching and clamping a thin (1/8 inch) circular elastic acrylic plate. Granular media (soil, masonry sand, glass beads, or even edible granular material) is supported at the bottom by the plate and side walls of the upper flange. A magnetic disk (1 cm) fastened below the plate (on center) is driven by a swept sinusoidal current in a coil placed below the magnet. This electrodynamic SPO, placed in a Wheatstone bridge, was used to measure the on-axis motional electrical impedance Zmot with and without granular loading. Nonlinear tuning curves near resonance exhibit softening with increasing drive amplitude. Measurements of Real{Zmot} and Imag{Zmot} were used to predict the nonlinear mechanical point impedance (Zmech = constant / Zmot) behavior of the SPO system. A lumped element model (granular media and elastic plate system) help determine the mesoscopic nonlinear properties of the granular media alone. Nonlinear tuning curves of the magnet’s acceleration were also measured. A bilinear hysteresis model fits the tuning curve results. See I. T. Perez-Miravete et al., JASA 125, 1302 (2009) for a nonlinear mesoscopic analysis of a flexural bar.

Nonlinear vibration experiment: Clamped circular elastic plate with granular material loading

Experiments using a soil-plate-oscillator (SPO) involve a vertical cylindrical column of granular medium (masonry sand, glass spheres, uncooked brown rice, un-popped popcorn kernels, or even “Toasty Oats” ™ cereal) that is supported by an air-backed thin circular elastic acrylic plate (20.3 cm diameter and 3.2 mm thick) that is rigidly clamped to the bottom of a thick-walled aluminum tube. The soil column is driven from below using an electrodynamic system. Here, an AC coil placed on axis and below the plate, drives a 1 cm diameter 1.5 cm long rare earth magnet that is fastened to the underside center of the plate. The coil is electrically driven by an amplified swept sinusoidal slowly varying chirp. A small accelerometer attached to the magnet is used to measure the vibration. In nonlinear tuning curve experiments the resonant frequency decreases significantly with increased amplitude—representing a softening in the nonlinear system. For fixed amplitude the resonant frequency vs. the granular medium mass loading (over the plate) reaches a minimum and then increases with increased loading due to the granular medium’s flexural stiffness—which overcomes the mass loading effects. For water loading, the frequency always decreases since there is no bending stiffness.

A soil-plate-oscillator apparatus for research projects and student demonstrations

In studying the complex vibration of compliant buried objects in soils, a simplified model apparatus called the “soil-plate-oscillator” (SPO) has been useful in understanding resonant behavior. The SPO is an open column of granular medium supported at the bottom by a thin circular clamped elastic plate. A rigid vertical circular sleeve (sidewall) keeps the soil in a circular column. Two 4.5 in. I.D. plastic PVC closet flanges are used to clamp a 1/8 in. thick acrylic plate. The elastic plate is driven from below by an AC coil located coaxially below a rare earth magnet (fastened to the plate’s underside at the center). An amplified swept sinusoidal chirp drives the coil. A small accelerometer, attached to the magnet, generates a charge amplified signal fed into a spectrum analyzer placed in the swept sine mode. Results for (a) dry sifted masonry sand and (b) 6 mm glass spheres are compared. In both experiments, the resonant frequency versus granular mass loading first decreases (reaching a minimum) and th...

Thermal performance of recycled aggregate mortar

When investigating the applicability of different materials for construction it is prudent to ensure that the materials used in replacement exhibit comparable performance to the natural material being replaced. This study uses a thermal conductivity analyser to determine the thermal conductivity and effusivity of standard normal weight masonry sand mortar specimens and several recycled and lightweight aggregates mortar specimens. R-values for each of the test mortars and the control mortar made with masonry sand was calculated with the control having the lowest R-value of the mortars tested. The results showed that replacing masonry sand mortar with any of the other mortars tested reduced the effect of thermal bridging through the mortar joint.

Electro-dynamic soil-plate-oscillator transducer for monitoring the buried vibration response to airborne sound excitation

A plastic drum-like anti-personal mine simulant (2 inch diam, by 1 inch tall, by ¼ inch thick aluminum tube, capped by a ¼ Al bottom circular plate and an elastic acrylic 1/16 inch thick circular top plate) was constructed. It was then modified to generate an electrical response to top-plate vibration. The mine simulant was converted to a transducer by fastened a sewing machine size bobbin wound with fine enamel copper wire onto the inside face on the bottom plate of the simulant. Next, a rare earth magnet was fastened to the inside surface of the elastic top plate (using a tacky wax). Leads were connected using insulated feed through connectors to complete the transducer design. In testing out the electro-dynamic transducer landmine simulant, results showed that the design was adequate to detect the vibration resonant response using a 2 inch burial depth in a concrete soil box filled with dry masonry sand. Two 12 inch diameter subwoofers were located a meter above the soil box and radiated sound levels on the order of 80-90 dB re 20 micro Pa, were measured near the soil surface. The swept sinusoidal transducer/microphone response exhibited a fundamental resonance near 190 Hz.

Effects of Media and Plant Selection on Biofiltration Performance

AbstractThe goal of this research was to compare the pollutant removal effectiveness of biofiltration systems containing different media and plant species. A laboratory column study was conducted by using three media and two plant species, each with and without a submerged zone intended to promote denitrification. Twenty experiments were run by using synthetic storm water over the course of nine months, and ten of them were analyzed. The three media used were concrete sand, masonry sand, and a medium that meets the City of Austin’s biofiltration specifications. The plant species were Buffalograss 609 and Big Muhly, both commonly found in Texas. The results of this study showed a significant improvement in nutrient removal with the presence of these plants in the filter. The columns without plants were found to export substantial amounts of nitrate/nitrite, whereas the columns with the plants demonstrated a substantial removal of nutrients (59–79% of the total nitrogen and 77–94% of the total phosphorus). ...

Hands-on demonstrations for Project Listen Up: Education outreach part III

Midshipmen will be getting involved in an ASA education outreach effort by presenting or recording a number of acoustical demonstrations geared to promote a hands-on learning experience for middle- and high-school age girl scouts. This is an extension of the demonstration effort and outreach presented at the ASA Meeting held in Baltimore in 2009 and Seattle in 2011. The demos are designed to visualize certain wave effects that will be explained by the Midshipmen “live” or by computer video. The participants will be free to explore, control the apparatus, and make their own scientific discoveries. The hands-on demonstrations will include (1) a ripple tank with two separated periodic point sources or a plane wave source driver for wave studies, (2) an ultrasonic motion sensor for measuring and displaying displacement, particle velocity and acceleration of an oscillating object or a person's motion, (3) tuning forks matched to Helmholtz resonators, and (4) a driven clamped circular plate supporting a column of dry sifted masonry sand (or uncooked rice or grass seed) for studying the resonant frequency versus. granular mass loading.

Evaluation of parametric array technology for acoustic landmine detection.

There has been interest in using the parametric array for obtaining a highly directional low frequency source in acoustic landmine detection [M. S. Korman, J. Acoust. Soc. Am. 122 (2007)]. Earlier experiments used a 0.5 m commercial parametric array made up of 70 elements located 1.5 m directly over the target. The array was driven by a 110–1100 Hz swept sine audio modulated 65 kHz tone. A VS 1.6 inert plastic antitank landmine was buried 2.5 cm deep in dry sifted masonry sand in a concrete box. The laser Doppler vibrometer to microphone rms response was sufficient to measure the “on target” to “off target” contrast ratios of 20 and 3 for peaks near 850 and 1050 Hz, respectively (upon signal averaging) but missed the largest peak near 150 Hz (where the SPL was 40 dB per 20 μPa) among others. Recent “forward looking” experiments aligned the array beam axis at 30° from grazing. Sweeping from 110–210 Hz (1600 points) at 16 s/sweep and signal averaging 20 sweeps produced a contrast ratio of 10 for resonance at 148 Hz. Considerable improvement in SPL is necessary in order to make this technology practical for low frequency applications. [Work supported by ARL.]

Nonlinear acoustic landmine detection: Comparison of tuning curve experiments profiling on and off the target

Recent experiments [Proc. SPIE 6217, 62170Y, Detection and Remediation Technologies for Mines and Minelike Targets XI; J.T. Broach, R.S. Harmon, J.H. Holloway, Jr.; Eds. (2006)] have shown that the soil vibrating over a drum-like acrylic landmine simulant is more nonlinear on the target than well off (due to soil alone). Here, a Laser Doppler Vibrometer (LDV) is configured to scan laterally across the buried simulant. The 10 cm diameter, 5 cm high rigid simulant has a flexible clamped 0.8 mm thick top plate and is buried 4 cm deep in dry, sifted masonry sand in a rigid soil container placed inside the anechoic chamber. At each location the sand is subjected to a series of increasing amplitude acoustic pressure level sweeps (across a 50–200 Hz bandwidth) that includes the resonant behavior. The soil surface particle velocity vs. frequency tuning curves, from locations ‘‘off target’’ show relatively small nonlinear effects, while those from locations ‘‘on target’’ exhibit clearly identifiable backbone (peak amplitude vs. corresponding resonant frequency) curves that exhibit softening. Profiles of the backbone slope vs. position indicate an extremely large contrast ratio between ‘‘on’’ and ‘‘off’’ locations compared to profiles of surface vibration obtained near resonance. [Work supported by ONR.]

Germinating seeds of:Lesquerella perforataandstonensis:substrate effects and mucilage production

Seeds of the rare annuals <i>Lesquerella perforata</i> Rollins and <i>L. stonensis</i> Rollins (Brassicaceae) germinated to higher percentages on topsoil and filter paper than on masonry sand and play sand. In addition, mucilage production was consistently less on topsoil than on the 2 types of sands. An increase in mucilage thickness was correlated with a reduction in germination. Although mucilage production has been observed under laboratory conditions, it has not been observed in nature. We recommend germinating seeds of both <i>Lesquerella</i> species on topsoil or filter paper for best results.