Plastic Balls Research Articles

The Study of Immobilized Media and Ni Ion Addition Effects on COD Removal of POME Using Anaerobic Filter Reactor

Palm oil mill effluent (POME) liquid waste contains high organic compounds. It has a high potential to be processed into biogas. One of the technologies that has been developed in processing POME is Fixed Film Bioreactor or anaerobic filter reactor (AFR). AFR is able to handle waste with high organic loading rate by using bacterial attached growth solid media on the surface of the media to form biofilm, which creates an optimum environment to microorganism growth and metabolism. Plastic balls (bio-balls) is one of the potential immobilization media due to chemically inert and lightweight. In addition, trace elements may enhance methanogens activities. This study aimed to evaluate the effect of bioball as an immobilization media and the addition of trace element Ni to anaerobic digestion process with POME substrate in terms of decreasing soluble chemical oxigen demand (sCOD) and methane production on fixed bed reactor in batch and continuous mode in sequence. The best performance of the reactor was able to reduce 92% of COD content inside the pome by 5 L/day of loading rate of 24,000 ppm POME.

Influences of an artificial three-dimensional cementitious network on the fracture property of cement casting asphalt mixture

Taking good advantage of both rigid cement and flexible asphalt mixture, cement casting asphalt mixture is developed to address the traditional distress in asphalt pavement. However, the relatively poor cracking resistance of CCAM limits its application in practice. Since the cracking mechanism of CCAM is still unknown, modification on the mixture design of CCAM cannot be done. In this regard, this paper focuses on investigating the influences of an artificial three-dimensional cementitious network on the fracture property of CCAM. In order to simulate the cementitious network, the pore structure in the prism sample is formed by using plastic foam balls of different sizes. The mechanical properties of beam samples at different curing days are measured. The semi circular bending test is used to characterize the strength and fracture properties of CCAM with different grouting materials. It is shown that the pore structure lowers the strength of the prism beams. Pore structures would induce more loss to the compressive strength of the beam samples than to its flexural strength. The cracking resistance of CCAM is determined by the asphalt mixture skeleton and cement network by analyzing the fracture energy and FI data. It is found that the compressive/flexural (C/F) ratio of the prism beam with 1 cm diameter plastic foam balls correlates well with the FI result of the CCAM. The results show that a moderate C/F ratio would make CCAM have fracture energy and flexibility, which makes it difficult for cracks to readily initialize and develop. The findings in this paper would provide guidance for the further selection of cementitious materials for the fabrication of CCAM with an excellent pavement performance.

Volume fracturing Of Temporary plugging Agent for Oil Well

There are many classification methods for temporary plugging volume fracturing. According to different temporary plugging positions and temporary plugging targets, temporary plugging volume fracturing technology can be divided into temporary plugging in fractures and temporary plugging between fractures. According to the number of temporary plugging, it can be divided into one temporary plugging and multi-level temporary plugging. According to the action mode of temporary plugging, it can be divided into physical temporary plugging and chemical temporary plugging. According to the type of temporary plugging agent, it can be divided into plugging balls (plastic balls, rubber balls, nylon balls, wax balls) temporary plugging, fiber temporary plugging, large particle size proppant temporary plugging, etc. In Changqing, Daqing and Xinjiang oilfields in China, temporary plugging agents have been reported to be used for in-fracture diversion fracturing to improve reservoir productivity, and certain effects have been achieved. Compared with conventional staged fracturing, the temporary plugging of the seam to fracturing technology has the following advantages: conventional staged fracturing is difficult to implement, the temporary plugging of the seam to fracturing technology can be used to realize effective layering (segment) reconstruction, general fracturing reconstruction is insufficient, and temporary plugging of the seam to fracturing can be used to improve thereconstruction effect.

Investigation of flexural and shear behaviors of biaxial voided slabs containing steel cages

AbstractIn some of biaxial voided slabs, spherical or ellipsoidal plastic balls enclosed in steel cages are used to eliminate ineffective concrete. To investigate the bending and shear behavior of this system, five full‐scale specimens were cast including two bending specimens for investigating bending capacity and cracking distribution as well as three shear specimens used to study the shear capacity, cracking distribution, and concrete casting effect on the shear behavior. Moreover, the effects of the steel cage rods were studied on the bending and shear capacity. It was found that while both solid and biaxial voided specimens exhibited almost similar failure mode, both the bending and shear capacity of biaxial voided specimens were affected by the steel cages. In contrast, the voided specimens exhibited a significantly lower shear capacity than the solid ones while the different concrete casting methods had no effects on the capacity and behavior of biaxial voided specimens. Finally, a comparison was made with experimental results and ACI 318‐14, MC 2010, and Eurocode 2 recommendations.

Feasibility study of Compton imaging for PGAA

We are developing a one-sided tomographic method for imaging prompt gamma rays, without moving the source, sample, or detector, in a standard prompt gamma activation analysis setting. Dual-plane pixelated CdZnTe detectors developed from a commercial system with external timing synchronization electronics are used to measure prompt gamma rays that are scattered in the first plane and subsequently absorbed in the second plane. Tomographic images have been reconstructed from the 2.2 MeV gamma rays from H in 3 mm plastic balls using inter-plane events for the first time, demonstrating the feasibility of spatially resolving mm scale H features.

High-intensity and low-divergence THz laser with 1D autofocusing symmetric Airy beams

Single-mode THz quantum-cascade lasers (QCLs) have been realized using a wide variety of techniques to obtain a combination of large power output, good beam quality with single-lobed beams, and low far-field divergence. Beam shaping using external components has not been previously exploited due to limited commercial availability of THz optical components and also the accompanying large loss from most THz optical materials. Here, we demonstrate that excellent beam characteristics could be obtained for a THz QCL by integration of a surface-emitting distributed-feedback (DFB) QCL with a simple lens within the vacuum chamber of a cryocooler. Plano-convex lenses are made from inexpensive plastic balls and integrated in proximity with a 3.4THz DFB QCL. With appropriately chosen lens parameters, dual-lobed Airy beams are generated that autofocus into a high-intensity single-lobed beam with large focusing efficiency. A simple and general method to generate one-dimensional autofocusing Airy beams is thus demonstrated that is applicable at any wavelength. THz laser beams with high peak intensity (57mW/mm2 in a spot-size of 1mm2) or low-divergence (1.4∘×1.8∘ for a beam with 118mW peak power) are realized at 62K in a compact electrically operated Stirling cooler. A high brightness of 5.4×106Wsr-1m-2 is estimated for the focused beams by measuring the beam propagation ratios (M2 parameters).

Enhancement of using combined packing materials on the removal of mixed sulfur compounds in a biotrickling filter and analysis of microbial communities

BackgroundPacking materials is a critical design consideration when employing biological reactor to treat malodorous gases. The acidification of packing bed usually results in a significant drop in the removal efficiency. In the present study, a biotrickling filter (BTF2) packed with plastic balls in the upper layer and with lava rocks in the bottom layer, was proposed to mitigate the acidification.ResultsResults showed that using combined packing materials efficiently enhanced the removal performance of BTF2 when compared with BTF1, which was packed with sole lava rocks. Removal efficiencies of more than 92.5% on four sulfur compounds were achieved in BTF2. Average pH value in its bottom packing bed was about 4.86, significantly higher than that in BTF1 (2.85). Sulfate and elemental sulfur were observed to accumulate more in BTF1 than in BTF2. Analysis of principal coordinate analysis proved that structure of microbial communities in BTF2 changed less after the shutdown but more when the initial pH value was set at 5.5. Network analysis of significant co-occurrence patterns based on the correlations between microbial taxa revealed that BTF2 harbored more diverse microorganisms involving in the bio-oxidation of sulfur compounds and had more complex interactions between microbial species.ConclusionsResults confirmed that using combined packing materials effectively improved conditions for the growth of microorganisms. The robustness of reactor against acidification, adverse temperature and gas supply shutdown was greatly enhanced. These provided a theoretical basis for using mixed packing materials to improve removal performance.

Making It Clear: Exploring Crystal Structures by Constructing and Comparing See-Through Models

Acquiring a basic understanding about the composition of crystal structures and the resulting structure–property relationship is central for chemists and material chemists, enabling the prediction of desired properties and the solution of a wide range of current challenges in sciences, e.g., the development of clean-energy storage. For a deeper understanding of physical and chemical properties of crystals, it is necessary to focus on different global and local structural features that characterize the composition of several atoms or ions as well as the direct environment of single atoms or ions. To improve students’ mental visualization of both global and local features of the three-dimensional order of crystal structures, we developed and implemented a modeling activity with new transparent models. During the activity, students construct and compare models of common crystal structures, like sodium chloride and zinc blend. The usage of clear plastic balls, in particular, allows students to focus on global features such as packing arrangement and lattice structure, as well as on local ones, like coordination number, site occupation, and polyhedral connectivity. The latter features have been difficult to realize so far. We used a design-based research approach to improve the activity and the instructional material, provided herein, through several rounds of evaluation in a course for undergraduate students in materials chemistry. A detailed qualitative analysis of students’ discourse during the activity revealed that students were engaged in various content-related interactions with the models and that it is beneficial to combine a student-centered construction of the models with a subsequent comparison phase.

Speed and spin differences between the old celluloid versus new plastic table tennis balls and the effect on the kinematic responses of elite versus sub-elite players

This study measured 1) the speed and spin differences between the old celluloid versus new plastic table tennis balls at pre ball-table impact and post ball-table impact when projected with topspin at 7.56 m.s-1, and investigated 2) the effect this has on the kinematic responses of 5 elite versus 5 sub-elite players’ forehand topspin in response to topspin and backspin. Plastic balls were lower in both speed and spin at pre and post ball-table impact compared with celluloid balls but the magnitude of change in speed and spin for each ball material differed. During flight before impact, plastic balls lost 3.98% more speed and 1.24% more spin than celluloid balls. Post ball-table impact, plastic balls showed a greater speed increment (0.69%) and smaller spin decrement (0.19%) than celluloid balls. Differences in players’ kinematic responses to the different ball materials were found only when players returned backspin shots. Players supinated their rackets more by 2.23% at ball-racket contact and produced 3.37% less ball spin when returning plastic compared with celluloid balls; an indication of an early adaptation to the lower spin rate of plastic balls. The lack of differences in kinematic response to topspin may be due to the similar changes in speed and spin of both types of balls at ball-table impact. It is not known if a higher initial ball projection velocity would evoke differences in movement responses from the players post ball-table impact but could be explored in future studies.

Numerical Analysis of Shear Strength Behavior of self-compact reinforced concrete Two-way Bubble Deck Slab with Shear Reinforcement

Bubble Deck is a new construction technology uses hollow plastic balls to eliminate the concrete in the middle part of the solid slab which has a little effect on the performance of the structure. So, this part significantly decreases the self-weight of the structure. Usually, the most critical point in the design of the bubbled slab is the design of a slab-column connection due to the concentration of loads and moments. This paper presents a numerical analysis by ABAQUS/2018 program through using the damage plasticity model to simulate the influence of the cavities due to using the plastic balls on the punching behavior and the effect of strengthening the punching zone by using different shear reinforcement systems on the maximum punching load and deformation capacity. Three slab specimens from the numerical analysis model have been simulated against the experimental results. The calculation of error in the model lies between 4% and 6%. Parametric of study have also been accomplished to realize the effect of the changes in shear reinforcement ratio with bubble slab. It has found that the ultimate strength and deformation capacity have increased when shear reinforcement ratio.

MACROMECHANICAL ANALYSIS OF SPHERICALLY VOIDED BIAXIAL CONCRETE SLABS

The use of spherically voided biaxial concrete slab (SVBS) system, which uses hollow plastic balls as infill material, has increased widely because of its reduced weight-to-strength and weight-to-stiffness ratios when compared to solid concrete slabs. However, SVBS is a heterogeneous composite structure in which building a representative continuum model poses a significant challenge. To mitigate this challenge, the feasibility of determining the macromechanical structural behavior of spherically voided biaxial concrete slabs is studied using plate theories, aided by mechanical properties that were determined from a homogenization process of the representative volume element (RVE). This paper presents numerical analysis results of SVBS using both Mindlin-Reissner (thick) and Kirchhoff-Love (thin) plate theories. The results from both theories predicted the slab behavior reasonably well and they were within 10% of each other with the exception of the prediction of the twisting moment. Possible explanation of this deviation is provided in the paper.

Effect of Construction Type on Structural Behaviour of R.C Bubbled One-Way Slab

Using Bubbles in the slab is a revolutionary method of eliminating concrete from the middle of conventional slab as this concrete does not perform any structural function, thereby dramatically reducing structural dead weight. This research presents experimental study to investigate the effect of construction type on the strength and behaviour of bubbled one-way slabs. The experimental program consists of testing four slabs with dimensions of 1850mm×460mm×110 mm. One1of the tested slabs was conventional slab (without bubbles), two bubbled slabs with different types of construction (simple and filigree bubbled slabs) and the remaining one is filigree bubbled slab strengthened with steel cage. The bubbles were made of recycled plastic balls. The experimental results show that the stiffness reduction factor for all the bubbled slabs was (0.87), this leads to decrease the ultimate strength of bubbled slabs and to be smaller than that of the solid slab by 4.4% 69% and 1.7% respectively. Also an increase in deflection at yield load (∆y) by about (10% to 12%), at the same time the crack load is found to be decreased by (13% to 40%). The simple bubbled slab is more efficient when compared with filigree bubbled slab. Also the results show that the use of steel cage in filigree bubbled slab gives an increase in the ultimate load by 69% and an increase in the ultimate deflection by about 77% when compared with filigree bubbled slab without steel cage.

Interaction effects of pen environment and sex on behavior, skin lesions and physiology of Windsnyer pigs.

ObjectiveThe study was carried to determine the interaction effects of pen enrichment and sex on behavioral activities, skin lesions and physiology of Windsnyer pigs.MethodsForty-eight growing Windsnyer pigs of both sex, with an average initial body weight of 21.6 (±9.01) kg were used. Four pigs were randomly assigned to either enriched or barren pens at a stocking density of 0.35 m2/pig. Enriched pens contained 2 L bottles filled with stones and suspended at head level on ropes stretching across the pens. In addition, two plastic balls (90 mm in diameter) and 500 mL bottles (235 mm long) were placed on the floor of each enriched pen.ResultsPigs in barren environments had higher heart rates (p<0.001) than those in enriched pens. There was an interaction of pen environment and sex on rectal temperature (p<0.001). Females in enriched pens had higher rectal temperatures (p<0.05) than females in barren pens. There was no interaction of pen environment and sex on time spent eating and drinking (p>0.05). Time spent bullying was influenced (p<0.05) by pen environment and sex. Female pigs in barren environment spent more time on bullying than females in enriched pens. There was an interaction of pen environment and sex on time spent lying down and walking (p<0.05). Female pigs in enriched pens spent more time lying down than females in barren pens. Males in barren pens spent more time walking than males in enriched pens while no effect of pen environment was observed in females. There was an interaction of pen environment and sex on the number of skin lesions in the head, neck and shoulder region and other parts of the body (p<0.05).ConclusionIt was concluded that pen enrichment reduced the number of skin lesions and anti-social behaviors, especially for female pigs. There is a need, therefore of housing indigenous pigs under confinement.

Effect of incorrect sound velocity on synthetic aperture sonar resolution

Synthetic aperture sonar (SAS) is an imaging technique to produce centimeter resolution over hundreds-of-meter range on the sea floor, by constructing a virtual aperture whose length automatically adjusts itself for a given focusing range. SAS is near-field acoustic imaging, and this implies that the sound velocity should be accurately estimated for well focused imaging. Otherwise there will be image quality loss. However, sound velocity in the ocean varies with space and time, and there might also be measuring error of CTD (Conductivity, Temperature, and Depth) sensor, so sound velocity error has become one of the limiting factors to improve SAS resolution further. To characterize the effect of sound velocity error quantificationally, the practice SAS resolution is mode as the convolution of ideal seafloor reflectivity function and a phase error function in frequency domain, where the phase error is caused by incorrect sound velocity. Then the SAS resolution parameterized is calculated as a function of the sound velocity measuring error, or sound velocity gradient. It is shown that SAS azimuthally (along track) resolution loss, caused by sound velocity measurement error, increases linearly with detection range. Meanwhile the loss caused by sound velocity gradient increases squarely. It is simulated by considering the synthetic aperture data collection for a particular pixel, and results show that the point scatter response will defocus when the sound velocity measuring error is up to 1% at 200m range, or the sound velocity changes up to 2% over a typical gradient at 200m range, and be worse at a longer range. Furthermore, we demonstrate the influence of sound velocity errors on SAS imagery using a sea trial data and real CTD measurements at South China Sea. We evaluate the degradation in image quality with respect to sound velocity errors by using two plastic balls and a variable seafloor scene, and results also support the accuracy of theoretical conclusions above.

FIELD INVESTIGATION IN THE DETONATION BEHAVIOR OF EMULSION EXPLOSIVE COLUMN INDUCED WITH AIR GAPS

In blasting of soft to medium hard rock, the problem of high density resulting in excessive utilization of emulsion explosive is well known. The authors have conducted some experimental blasts to delve into the detonation behavior of conventional blasting and various other explosive consumption reduction techniques which induce air gaps using plastic tubes, plastic bottles or plastic balls in the explosive column. Resistance wire technique is used for gauging in-hole continuous velocity of detonation. The VOD varies from 5321.6 m/s to 4544.2 m/s and from 5123.4 m/s to 4274.2 m/s in conventional site mixed emulsion column and distributed spherical air gap column respectively. The detonation behavior is stable and similar in both these cases. While using plastic bottles or plastic tubes as air gaps, the VOD is fluctuating from 4636.3 m/s to 3268.4 m/s and from 4935.9 m/s to 3362.8 m/s respectively with a collapse of about 12 % from the average VOD of conventional SME column. The VOD falls abruptly when the detonation wave encounters large air gaps but it is successfully travelling through the air gaps making the detonation behavior more capricious.

Experimental study on a solar assisted heat pump desalination unit with internal heat recovery based on humidification-dehumidification process

On-going study on the humidification-dehumidification (HDH) desalination has proved that internal heat recovery is a significant and potential method for improving the system performance and reducing the fresh water cost. In this paper, a novel solar assisted heat pump (SAHP) with internal heat recovery desalination system based on HDH process is proposed and studied experimentally. The objective of this study is to investigate the ability of heat recovery in improving the system performance and obtain the optimal operating parameters. Based on the experimental results, it can be concluded that the fresh water cost of the two-stage HDH desalination system is reduced by 17.36%, and system productivity and gained-output-ratio (GOR) are increased by 15.51% and 55.64%, respectively compared with those of the single-stage. Particularly, benefiting from energy cascade utilization, the distribution ratio is introduced to further improve the system performance, which is affected strongly by the cooling seawater flow rate. Furthermore, a comparison of the humidifier materials between plastic polyhedron empty balls (PPEBs) and honey-comb paper indicates that the increment in system productivity by PPEBs is 27.76% lower than that by honey-comb paper with a reasonable specific surface area.

Experimental study of the particle motion in flighted rotating drums by means of Magnetic Particle Tracking

The particle motion in flighted rotating drums (FRD) is still not fully understood due to the many influencing variables and its complexity. The method of Magnetic Particle Tracking (MPT) offers new possibilities for this purpose. In this work, the MPT is adopted and applied to study particle motion in FRD for the first time. The experiments were conducted using plastic balls and soybeans at 5% filling degree under various drum rotating speeds (10 rpm–40 rpm). Particle trajectories, translational velocity distributions, rotational velocity distributions, falling time of dilute phase, and instantaneous velocity of dilute phase in the equatorial region of the drum were studied. As the measurements revealed, the particle motion in flighted rotating drum is strongly influenced by the drum rotating speed and slightly affected by particle size and shape in the range investigated here.

Programmed Deformations of 3D‐Printed Tough Physical Hydrogels with High Response Speed and Large Output Force

AbstractShape‐morphing hydrogels have emerging applications in biomedical devices, soft robotics, and so on. However, successful applications require a combination of excellent mechanical properties and fast responding speed, which are usually a trade‐off in hydrogel‐based devices. Here, a facile approach to fabricate 3D gel constructs by extrusion‐based printing of tough physical hydrogels, which show programmable deformations with high response speed and large output force, is described. Highly viscoelastic poly(acrylic acid‐co‐acrylamide) (P(AAc‐co‐AAm)) and poly(acrylic acid‐co‐N‐isopropyl acrylamide) (P(AAc‐co‐NIPAm)) solutions or their mixtures are printed into 3D constructs by using multiple nozzles, which are then transferred into FeCl3 solution to gel the structures by forming robust carboxyl–Fe3+ coordination complexes. The printed gel fibers containing poly(N‐isopropyl acrylamide) segment exhibit considerable volume contraction in concentrated saline solution, whereas the P(AAc‐co‐AAm) ones do not contract. The mismatch in responsiveness of the gel fibers affords the integrated 3D gel constructs the shape‐morphing ability. Because of the small diameter of gel fibers, the printed gel structures deform and recover with a fast speed. A four‐armed gripper is designed to clamp plastic balls with considerable holding force, as large as 115 times the weight of the gripper. This strategy should be applicable to other tough hydrogels and broaden their applications.

All play and no work: skits and models in teaching skeletal muscle physiology.

All play and no work: skits and models in teaching skeletal muscle physiology.

Demonstrating the “unit hydrograph” and flow routing processes involving active student participation – a university lecture experiment

Abstract. The unit hydrograph (UH) has been one of the most widely employed hydrological modelling techniques to predict rainfall–runoff behaviour of hydrological catchments, and is still used to this day. Its concept is based on the idea that a unit of effective precipitation per time unit (e.g. mm h−1) will always lead to a specific catchment response in runoff. Given its relevance, the UH is an important topic that is addressed in most (engineering) hydrology courses at all academic levels. While the principles of the UH seem to be simple and easy to understand, teaching experiences in the past suggest strong difficulties in students' perception of the UH theory and application. In order to facilitate a deeper understanding of the theory and application of the UH for students, we developed a simple and cheap lecture theatre experiment which involved active student participation. The seating of the students in the lecture theatre represented the “hydrological catchment” in its size and form. A set of plastic balls, prepared with a piece of magnetic strip to be tacked to any white/black board, each represented a unit amount of effective precipitation. The balls are evenly distributed over the lecture theatre and routed by some given rules down the catchment to the “catchment outlet”, where the resulting hydrograph is monitored and illustrated at the black/white board. The experiment allowed an illustration of the underlying principles of the UH, including stationarity, linearity, and superposition of the generated runoff and subsequent routing. In addition, some variations of the experimental setup extended the UH concept to demonstrate the impact of elevation, different runoff regimes, and non-uniform precipitation events on the resulting hydrograph. In summary, our own experience in the classroom, a first set of student exams, as well as student feedback and formal evaluation suggest that the integration of such an experiment deepened the learning experience by active participation. The experiment also initialized a more experienced based discussion of the theory and assumptions behind the UH. Finally, the experiment was a welcome break within a 3 h lecture setting, and great fun to prepare and run.