Hollow Ball Research Articles

4D printing of Nd-Fe-B composites with both shape memory and permanent magnet excitation deformation

Novel composite filaments are developed by mixing PLA, TPU, and Nd-Fe-B components and utilizing melt extrusion for 4D printing. The results reveal that the Nd-Fe-B magnetic particles are uniformly dispersed in the PLA/TPU polymer matrix, and the composite filaments meet the requirements of high-precision printing. Increasing the proportion of Nd-Fe-B magnetic particles in the composite contributes to higher remanence, coercivity, and magnetic energy product for the printed magnets. Under the 70 °C thermal stimulus, it has a high shape fixed ratio (>99 %), a high shape recovery ratio (>90 %), and a rapid response time (≤6.55 s). The magnetic particles accelerate the shape recovery process. Moreover, the petal-like structure and the hollow ball structure are designed and printed. After deformation, each structure can nearly fully recover its initial shape. This recovery is achieved through a non-contact stimulus response based on ’thermal-magnetic’ coupling. The grippers printed by the developed composite show comprehensive properties of shape memory and magnetically controlled smart gripping.

Photocatalytic properties of bismuth-rich Bi4O5I2/BiOBr flowers prepared by one-step solvothermal method were studied

In this paper, bismuth-rich three-dimensional Bi4O5I2/BiOBr hollow flower spheres were prepared by a one-pot solvothermal method. The anionic contaminant Rhodamine B (RhB) was used as the photocatalytic test contaminant. The results showed that the degradation rate of RhB was more than 99 %. Then Br element was introduced into Bi4O5I2 hollow flower balls, the diameter of flower balls decreased and flowers sparsely. With the increase of Br content, flower balls gradually increased in volume and became denser. Small and sparse flower balls increase the specific surface area of flower balls and increase the number of active sites, thus improving the REDOX capacity of photogenerated electrons and holes. Our findings suggest that both holes (h+) and superoxide radical anions (•O2−) are crucial players during photocatalysis. The aim of this study is to develop an efficient photocatalyst for the degradation of organic pollutants, and its photocatalytic mechanism is described theoretically.

MODELING OF A LIGHTWEIGHT FLAT FLOOR WITH VOIDS MADE OF PLASTIC BALLS

Formulation of the problem. Prefabricated monolithic construction in domestic and global practice in recent years has occupied a small share in the field of construction. A fairly large number of designs of prefabricated monolithic lightweight floors, as well as its individual structural elements, have been proposed. The use of lightweight floors in the construction of residential and public buildings can significantly reduce the consumption of materials and the dead weight of structures and increase the size of live loads and overlapping spans. Despite this, it cannot be said that effective design solutions have been found that can maximally satisfy the requirements of consumers, architects and builders. Based on this, a constructive solution for a lightweight prefabricated monolithic floor with voids made of plastic balls, quite effective from the point of view of construction and subsequent operation, was proposed and investigated. The proposed design solution for a lightweight prefabricated monolithic flat floor with voids made of plastic balls has less mass than solid floors and optimal use of material resources, namely the consumption of concrete and reinforcement. Therefore, research to determine the optimal design parameters of a flat lightweight floor with void formers made of plastic balls is relevant. The purpose of the article is to conduct numerous studies of the stress-strain state of the proposed design of a prefabricated monolithic floor with voids made of plastic balls. Conclusion. As a result of the research, it was established that it is rational to use hollow balls made from recycled materials as a material for making voids from balls in flat floors. Moreover, all studied floor options with spans of 6 m, 7 m, 8 m and void sizes made of balls with diameters of 180 mm, 315 mm and 500 mm meet the requirements of the first and second groups of limit states.

SELECTION OF OPTIMAL PARAMETERS OF A LIGHTWEIGHT FLAT FLOOR WITH VOIDS MADE OF PLASTIC BALLS

Formulation of the problem. Architectural and construction design of buildings using reinforced concrete has led to an increase in the number of objects with an individual space-planning structure, a rich variety of facade and volumetric solutions. Today the question of the effectiveness of using flat prefabricated monolithic lightweight floors in the construction of multi-storey buildings with individual space-planning and architectural solutions is relevant. In a market economy interest in the issue of rational use of resources, namely the cost of concrete and reinforcement in construction, has sharply increased, which is directly related to attracting investment. As it is known, when designing buildings from prefabricated monolithic reinforced concrete, in contrast to prefabricated concrete, there is greater freedom in adopting the space-planning parameters of the building, and there may also be simpler design solutions, in particular for floors. The constructive solution of floors depends on numerous requirements for the building as a whole and directly for the floor. One of the requirements that influences the attraction of investments is a small material-intensive floor covering with significant spans of buildings of various structural systems. The effective use of lightweight precast monolithic reinforced concrete floors with voids made of plastic balls in construction requires a comprehensive technical and economic analysis of this innovative solution for the precast monolithic reinforced concrete floor structure. The purpose of the article is to perform a technical and economic comparison of various design options for a flat lightweight prefabricated monolithic floor. The influence of floor parameters on the consumption of concrete and reinforcement is considered. Conclusion. As a result of the research, it was established that it is rational to use hollow balls made from recycled materials as a material for making voids from balls in flat floors. Moreover, all studied floor options with spans of 6 m, 7 m, 8 m and void sizes made of balls with diameters of 180 mm, 315 mm and 50 0mm meet the requirements of the first and second groups of limit states.

ТЕХНОЛОГИЯ ЗАМКНУТОГО ЦИКЛА ПОЛУЧЕНИЯ СТРОИТЕЛЬНОГО ГИПСА ИЗ ОТХОДА ЭНЕРГЕТИКИ И ДЫМОВЫХ ГАЗОВ ТЕПЛОВОЙ ЭЛЕКТРОСТАНЦИИ

A closed-cycle technology for building gypsum producing using energy waste and flue gases of thermal power plants has been developed. The technology is based on an absorption method for purifying gas emissions from industrial enterprises from sulfur dioxide SO2 using a suspension of carbonate sludge and obtaining a finished product – gypsum dihydrate. The commercial gypsum is obtained by using a suspension of carbonate sludge as a reagent. The suspension is formed at the stage of preliminary purification of natural water during coagulation and liming. Coagulation is carried out with ferrous sulfate heptate FeSO4×7H2O, liming – with a saturated solution of lime milk Ca(OH)2. As a result of combining the two processes, a suspension of a certain chemical composition is formed. The chemical composition of the sludge and its technological characteristics are presented. The main substance in the chemical composition is calcium carbonate CaCO3, which allows using a sludge suspension in the chemical reaction of the interaction of flue gases from thermal power plants with the formation of building gypsum. An absorber with a fluidized nozzle has been selected and designed to purify gas emissions from wet suspensions and produce commercial dihydrate gypsum. Hollow or solid hydrophobic polyethylene balls were selected as nozzles to reduce the adhesion of sludge suspension particles to their surface. A technological scheme is presented for purifying flue gases from sulfur dioxide to obtain the finished product – building gypsum. The scheme includes the proposed adsorber, sludge suspension tank, hydrocyclone and filter press. The cost of the resulting commercial building gypsum was calculated, which amounted to 15 rub./year, the payback period was 3,5 years. The prevented environmental harm from soil and land degradation from the introduction of this technology at thermal power plants was calculated by reducing the emission of sulfur dioxide into the air, which amounted to about 1 mil. rub./year.

"Microflower-Templated" Janus Sheets: Synthesis and Application in Stabilizing Foams.

In this study, we proposed a method for fabricating Janus sheets using biological "microflowers" as a sacrificial template. The microflower-templated Janus sheets (MF-JNSs) were employed as a foam stabilizer in foam separation of the whey soybean protein (WSP). The MF-JNSs took inorganic hybrid microflowers (BSA@Cu3 (PO4)2-MF) as template, followed by the sequential attachment of protamine and silica to the surface of the BSA@Cu3(PO4)2-MF. Subsequently, the template was removed using ethylenediaminetetraacetic acid after the silicon dioxide was modified by 3-(methacryloyloxy) propyl trimethoxysilane. Upon template dissolution, the modified silica layer, lacking support from the core, fractured to form the MF-JNSs. This method omitted the step of treating the hollow ball by external force and obtained Janus sheets in one step, indicating that it was simple and feasible. The morphology, structure, and composition of the MF-JNSs were analyzed by SEM, TEM, AFM, XRD, and FT-IR. The MF-JNSs were found to delay the breakage time of the Pickering emulsion, demonstrating their emulsion stabilizing capability. Importantly, they significantly enhanced the foam half-life and foam height of soybean whey wastewater (SWW). Moreover, the recovery percentage and enrichment ratio of WSP, separated from SWW by foam separation, were improved to 81 ± 0.28 and 1.20 ± 0.05%, respectively.

Highly Sensitive Iontronic Pressure Sensor with Side-by-Side Package Based on Alveoli and Arch Structure.

Flexible pressure sensors play a significant role in wearable devices and electronic skin. Iontronic pressure sensors with high sensitivity, wide measurement range, and high resolution can meet requirements. Based on the significant deformation characteristics of alveoli to improve compressibility, and the ability of the arch to disperse vertical pressure into horizontal thrust to increase contact area, a graded hollow ball arch (GHBA) microstructure is proposed, greatly improving sensitivity. The fabrication of GHBA ingeniously employs a double-sided structure. One side uses mold casting to create convex structures, while the other utilizes the evaporation of moisture during the curing process to form concave structures. At the same time, a novel side-by-side package structure is proposed, ensuring pressure on flexible substrate is maximally transferred to the GHBA microstructure. Within the range of 0.2Pa-300kPa, the iontronic pressure sensor achieves a maximum sensitivity of 10420.8kPa-1, pressure resolution of 0.1% under the pressure of 100kPa, and rapid response/recovery time of 40/35ms. In wearable devices, it is capable of monitoring dumbbell curl exercises and wirelessly correcting sitting positions. In electronic skin, it can non-contactly detect the location of the wind source and achieve object classification prediction when combined with the CNN model.

Formaldehyde degradation by soft-sliding-electrification-induced air ionization

Formaldehyde (HCHO), a highly toxic and carcinogenic gas, is the most common indoor air pollutant and a threat to human health. Developing simple and effective technological routes to achieve sustainable degradation of HCHO has become a common goal. In this work, we reported a self-powered air-ionized HCHO degradation system based on a soft-sliding freestanding mode triboelectric nanogenerator (SSF-TENG). The sliding-electrification process between soft rabbit fur and a robust PTFE film enables the generation of electrical outputs of up to ten thousand volts that can trigger air breakdown. The generated O3, ·OH and other highly oxidizing substances could degrade HCHO into CO2 and H2O. Through a standard ball gap platform based on two hollow Cu balls, the voltage of air discharge was measured to be between 11.2 kV and 14.4 kV. For demonstration, the SSF-TENG was applied to two parallel disk-shaped Cu electrodes to continuously breakdown the air with a peak discharge current of 6 mA. The system can produce a maximum O3 concentration of 1.2 ppm within 50 minutes. Moreover, the HCHO concentration can be reduced from 1.6 ppm to 0 within 20 minutes, and the degradation speed reaches 0.08 ppm/min. This work highlights the application of triboelectric microplasma in pollutant removal, which has great potential in self-powered environmental purification.

Core-shell PCM encapsulation model for thermoregulation of asphalt pavements

The implementation of cooler pavements plays an important role in alleviating the urban heat island (UHI) effect and extending the lifespan of pavements. One potential approach to develop cool pavements involves the incorporation of phase change materials (PCMs). In this study, a numerical investigation is conducted to evaluate the effectiveness of incorporating core–shell encapsulated PCMs within asphalt pavements. To facilitate this analysis, an enthalpy-porosity-based heat transfer model is developed, and its accuracy is validated through experimental data obtained in-house. For this study, commercially available PCMs, namely Organic Mixture 35 (OM 35) and Organic Mixture 42 (OM 42), encapsulated within hollow steel balls are used. The outcomes of the investigation reveal that the inclusion of core–shell encapsulated PCMs is a viable method for reducing the temperature of asphalt pavements. Further, it is found that as the thermal conductivity of asphalt pavements increases from 1.21 to 2.41 W/mK, there is corresponding proportional increase in the temperature reduction achieved by integrating the PCMs with the pavements. The proportional temperature reduction with increase in thermal conductivity of asphalt pavements are found to be 3.55 °C using OM 35 and 3.37 °C using OM 42 respectively. It is worth noting that while the thermal characteristics of the steel balls exhibit a limited influence on temperature reduction, their physical attributes should be given careful consideration during the design phase of asphalt pavements.

One-step biofabrication of liquid core-GelMa shell microbeads for in situ hollow cell ball self-assembly.

There are many instances of hollow-structure morphogenesis in the development of tissues. Thus, the fabrication of hollow structures in a simple, high-throughput and homogeneous manner with proper natural biomaterial combination is valuable for developmental studies and tissue engineering, while it is a significant challenge in biofabrication field. We present a novel method for the fabrication of a hollow cell module using a coaxial co-flow capillary microfluidic device. Sacrificial gelatin laden with cells in the inner layer and GelMa in the outer layer are used via a coaxial co-flow capillary microfluidic device to produce homogenous micro-beads. The overall and core sizes of core-shell microbeads were well controlled. When using human vein vascular endothelial cells to demonstrate how cells line the inner surface of core-shell beads, as the core liquifies, a hollow cell ball with asymmetric features is fabricated. After release from the GelMa shell, individual cell balls are obtained and deformed cell balls can self-recover. This platform paves way for complex hollow tissue modeling in vitro, and further modulation of matrix stiffness, curvature and biochemical composition to mimic in vivo microenvironments.

Investigation of the stress state of an elastic hollow ball during filtration of liquid through its wall

When determining the stress state of an elastic hollow ball when filtering liquid through its wall, it is necessary to solve the stress problem for the case of liquid filtration to the center of the ball with a decrease in pressure in its cavity. This case represents for us an element of the general problem of the stressed state of the annular filter behind the casing during well operation. First, the problem of liquid filtration is solved -pressure changes in the body under study are determined during liquid filtration. Then the equilibrium equation with respect to radial deformation is solved. A change in the sign of the filtration potential leads to a change in the tangential stresses on the well wall to a value equal to a tripled depression of reservoir pressure (with radial stresses equal to zero). This explains the negative effect of well shutdowns, and even more so the change in the direction of the filtration flow in the downhole part of the formation on the stability of the walls of wells, the operation of which is complicated by sand formation. The maximum difference of the main normal stresses is observed on the well wall, therefore, in order to prevent formation destruction near the bottom, a necessary condition is that the strength properties of rocks correspond to the stresses acting in this zone. When operating wells prone to plugging, it is necessary to limit the depression of reservoir pressure to the maximum permissible value when the material of the filter zone is in an elastic state throughout the volume.

Penerapan Bisnis Digital Untuk Pemasaran Bola Ubi Kopong Diperkotaan

The use of digital business is increasingly crucial in facing the era of globalization and technological advancements. This article discusses the implementation of digital business strategies to market a unique product, "Hollow Sweet Potato Balls," in urban areas. The research method employed is a case study, focusing on online marketing, social media, and e-commerce strategies to enhance visibility and product sales in the urban market.By leveraging these digital tools, the hollow sweet potato ball business can expand its market reach and enhance competitiveness in the competitive urban environment. The transformation into a digital business provides a better understanding for SMEs of consumer preferences and behaviors, enabling them to reach more specific customer segments. The use of social media platforms such as Facebook and Instagram also aids SMEs in marketing strategies and consumer interaction.Additionally, delivery services like GrabFood assist SMEs in adapting to the increasing demand for delivery services. In conclusion, SMEs need to adopt digital technology to adapt and thrive amidst the ongoing changes in the business landscape.

Approaches to the Solution of the Lamé–Gadolin Problem for a Composite Hollow Ball Made of Nonlinear Elastic and Elasto-Plastic Materials Under Superimposed Finite Deformations

Approaches to the Solution of the Lamé–Gadolin Problem for a Composite Hollow Ball Made of Nonlinear Elastic and Elasto-Plastic Materials Under Superimposed Finite Deformations

The Pendulum that Diagnoses and Cures

Abstract The example of medical radiesthesia illustrates how a new discipline may be elaborated and taken up by amateurs on the fringes of official academic science. Driven by scholarly discoveries about waves, it broke with the long tradition of dowsing while expanding its initial ambition, that of discovering hidden things by using an object to prolong the individual’s sensitivity. This break was materialised by the shift from rods to pendulums in the 1930s. Medical radiesthesia consists in using a pendulum—a simple object made of a solid or hollow ball of varying material oscillating on a cord—for diagnosis and therapy. It may be characterized as an amateur practice because radiesthesia was devised in the 1930s as a new discipline on the margins of professional scientific circles; and because it was theorised by non-doctors and practised mainly by people not involved in the world of professional healthcare.

Experimental study on the performance of phase change energy storage concrete for energy piles based on Gum Arabic and PEG-600

To produce phase change energy storage concrete, phase change materials (PCM) can be encapsulated and mixed into concrete. Phase change energy storage concrete energy piles demonstrate higher heat transfer efficiency than conventional ones. Concrete strength decreased by replacing coarse aggregates with phase change aggregates. Gum Arabic (GA) can enhance the strength of concrete and is more economical and environmentally friendly than mineral admixtures. This research manufactured PCM-HSB aggregates by encapsulating hollow steel balls (HSB) with polyethylene glycol 600 (PEG-600). GA is selected as an admixture to enhance the strength of concrete. The mechanical and thermal characteristics of GA-PEG-HSB concrete were tested at various GA admixtures (0.7%, 0.9%, 1.1%, 1.3%), and PCM-HSB replacement rates (15.0%, 17.5%, 20.0%). Determination of concrete characteristics by compressive strength, thermal conductivity, specific heat capacity, and Coefficient of thermal expansion (CTE). The test evidence shows that the PCM-HSB replacement rate has a negative correlation with the thermal conductivity of concrete but a positive correlation with the specific heat capacity. The compressive strength of the concrete was affected by GA, and the peak compressive strength of the concrete was reached at 0.9% dosage. The optimal ratio of GA-PEG-HSB concrete is water: cement: fine aggregate: coarse aggregate: PCM-HSB: GA=210: 500: 633: 842: 157: 1.89. The optimal replacement rate of the PCM-HSB is 20 %, and the optimal dosage of the GA is 0.9 %. The experimental results show that the mechanical and thermal properties of GA and PEG-600 phase change energy storage concrete are superior and meet the future development needs of energy pile technology.

Analysis of Two Schemes of Cold Forging of a Hollow Ball

Analysis of Two Schemes of Cold Forging of a Hollow Ball

Research on transient heat transfer of ball valves in high-pressure liquid hydrogen receiving stations

As one of the most important fluid control devices in the liquid hydrogen receiving station, the liquid hydrogen ball valve's performance directly affects the system's stability. Aiming at the problem of insufficient cold shrinkage compensation ability of ball valve under high-temperature difference and excessive flow rate during the working process, a high-pressure liquid hydrogen hollow ball valve with elastic compensation ability is designed. Based on the conjugate heat transfer method, the transient conjugate heat transfer and transient thermal stress analysis were carried out on the high-pressure hollow ball valve of the liquid hydrogen receiving station. The results show that the transient temperature of each part of the ball valve decreases under different flow rates, and the closer to the flow part of the medium, the faster the cooling. In the initial stage, the larger the flow rate of liquid hydrogen, the greater the heat flux density of the fluid-solid interface, but after a certain period, the large flow rate is cooled to a greater extent, the heat transfer is weakened, and the heat flux density is smaller. Under different flow rates, the transient thermal stress of the key components of the ball valve first increases sharply and then decreases. At large flow rates, the temperature change is more obvious, and the maximum stress of each component increases. The research results have guiding significance for designing and applying ball valves in high-pressure liquid hydrogen receiving stations.

Enhanced adsorption-photocatalysis synergy and stability of polypropylene photocatalytic floating ball benefitted from click chemistry connection

Floating photocatalytic materials provide an effective way for the practical application of photocatalytic technology. In this study, a highly efficient and stable polypropylene photocatalytic floating ball (CC-P25/BC@PP) was designed and synthesized via firstly coupling Degussa P25 with biochar (BC) through click chemical reaction, followed by loading the composites on PP hollow ball with help of titanate coupling agent. Statistical analysis found that, compared to the PP ball decorated with simple P25/BC mixture (denoted as Mix-P25/BC@PP), click chemistry connection not only significantly increased the effective loading limit of P25/BC composites on PP ball, but also enhanced the adsorption-photocatalysis synergy between TiO2 and biochar. As a result, the degradation rate constant of ciprofloxacin (CIP) was nearly doubled. Moreover, due to the strengthened connection between P25/BC composite with PP ball, stability of CC-P25/BC@PP was improved significantly, and the shedding rate of active ingredients from PP ball during cycling experiment, acid/alkali soak and ultrasonic oscillation were suppressed 3.80–6.71 times compared to Mix-P25/BC@PP. Therefore, the highly efficient and stable PP photocatalytic floating ball based on click chemistry reaction showed strong practical application potentials.

A novel regional force control strategy based on seven-axis linkage grinding system to improve blade machining accuracy

The aero-engine blade has the characteristics of large curvature and uneven allowance distribution, which makes it difficult to ensure its machining accuracy during processing. The existing research mainly realizes the removal of blade allowance through constant contact force control strategy, which is difficult to achieve accurate removal of uneven allowance. This paper proposes a novel regional force control strategy based on seven-axis linkage grinding system. The ideal contact force is obtained according to the curvature and allowance distribution at each cutter-contact (CC) point, and the coefficient kp is calibrated by orthogonal grinding tests considering the initial rapid wear of the hollow ball abrasive belt. The ideal contact force is controlled by the regional force control strategy, which is composed of the regional division and the seventh axis controller. Considering the system response time and the distribution of the ideal contact force, the ideal contact force is divided into several regions through regional division algorithm, and then the actual contact force is controlled in real time during processing by the designed seventh axis controller to ensure the stability of the seventh axis. The force control accuracy with the seventh axis controller has increased by 63.7 % on the whole profile of the blade than that without the controller. The comparative robotic grinding experiment results show that the surface profile accuracy values at the four profile areas are improved by 57.6 %, 59.2 %, 70 % and 61.7 % than that with the passive compliance control (PCC) method, respectively.

Synthesis of non-planar graphene-wrapped copper nanoparticles with iron(III) oxide decoration for high performance supercapacitors

The performance of supercapacitors strongly depends on the electrochemical characterizations of electrode materials. Herein, a composite material consisted of iron(III) oxide (Fe2O3) and multilayer graphene-wrapped copper nanoparticles (Fe2O3/MLG-Cu NPs) is fabricated on a flexible carbon cloth (CC) substrate via two-step synthesis process for supercapacitor application. Where, MLG-Cu NPs are prepared on CC by one-step chemical vapor deposition synthesis approach; thereafter, the Fe2O3 is further deposited on the MLG-Cu NPs/CC via successive ionic layer adsorption and reaction method. The related material characterizations of Fe2O3/MLG-Cu NPs are well investigated by scanning electron microscopic, high resolution transmission electron microscopy), Raman spectrometer and X-ray photoelectron spectroscopy; the electrochemical behaviors of the pertinent electrodes are studied by cyclic voltammogram, galvanostatic charge/discharge (GCD) and electrochemical impedance spectroscopy measurements. The flexible electrode with Fe2O3/MLG-Cu NPs composites exhibits the best specific capacitance of 1092.6 mF cm−2 at 1 A g−1, which is much higher than those of electrodes with Fe2O3 (863.7 mF cm−2), MLG-Cu NPs (257.4 mF cm−2), multilayer graphene hollow balls (MLGHBs, 14.4 mF cm−2) and Fe2O3/MLGHBs (287.2 mF cm−2). Fe2O3/MLG-Cu NPs electrode also exhibits an excellent GCD durability, and its capacitance remains 88% of its original value after 5000 cycles of the GCD process. Finally, a supercapacitor system consisted of four Fe2O3/MLG-Cu NPs/CC electrodes can efficiently power various light-emitting diodes (i.e. red, yellow, green, and blue lights), demonstrating the practical application of Fe2O3/MLG-Cu NPs/CC electrode.