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In order to study the physical and mechanical properties of gypsum rock samples in three states (natural, high-temperature dehydration and hydration time), natural gypsum rock was put into high-temperature condition of 220°C for dehydration treatment, and then the high-temperature dehydrated gypsum rock was treated with different hydration time, and the gypsum rock samples in three states were subjected to ultrasonic test, density test and uniaxial compression test. The results show that the main components of natural gypsum minerals were gypsum dihydrate (71%), dolomite (27%) and potassium chloride (2%). The hydration of high-temperature dehydration samples was an extremely complex physical and chemical process. Hydration had a significant strengthening effect on gypsum rock, and the weak surface of the structure had a significant weakening effect on it during the hydration process. As hydration time increased, the apparent density increased gradually and the longitudinal wave velocity increased. The peak strength of the sample decreased first and then increased, and it generally had a logarithmic relationship with hydration time. The peak strain decreased first and then increased, then decreased and fluctuated, and the elastic modulus first increased and then decreased and then increased again. The expansion rate and limited expansion force of the sample increased with increase in hydration time. After a certain hydration time, the expansion rate of the sample tended to be stable, while the limited expansion force began to decrease slowly after reaching the maximum value.

This paper presents an experimental investigation on the mechanical behaviour of the Self-stressing Steel Slag Aggregate Concrete Filled Steel Tubular (SSSACFST) short columns under axial compression. Ten SSSACFST short columns with different diameter-thickness ratios and expansion rates of Steel Slag Aggregate Concrete (SSAC) are designed, and three different axial compression tests are conducted including the load applied to the core SSAC (type-A loading), load applied to the outer steel tube (type-B loading), and load applied to the steel tube and core SSAC simultaneously (type-C loading). The experimental results show that all SSSACFST short columns subjected to axial load exhibit drum-like failures. The Incremental Range of Load Capacity (IRLC) and the ultimate axial and circumferential strains of the specimens will be improved by increasing the expansion rate. The effect of the loading mode on the ultimate bearing capacity is not very evident, while the influence of the loading mode on the strains is remarkable. The ultimate axial and circumference strains of the specimens with type-B loading mode are significantly larger than those of the specimens with type-A loading mode or type-C loading mode. The increase in the diameter-thickness ratio decreases the ultimate bearing capacity and ultimate axial and circumferential strains of the specimens. According to the experimental results, the adaptability of the existing CFST design codes for estimating the strength of SSSACFST short columns is examined. Additionally, a model for predicting the ultimate bearing capacity of SSSACFST short columns with the type-C loading mode is proposed depending on the limit equilibrium theory. On this basis, the calculation methods of the bearing capacity of the SSSACFST short columns under axial compression with the other two loading modes are suggested. The results predicted by the proposed models are in good agreement with the test data.

The low hydration activity and volumetric instability of steel slag (SS) limits its application as a binding material. SS contains approximately 30 pct of a divalent metal oxide solid solution (RO phase). According to the XRD results of the RO phase extracted from SS, RO phases (MgO·xFeO) with different compositions were synthesized to study their hydration activity and expansibility. The hydration activity of the RO phase was found to exponentially decrease with the increasing molar ratio (x) of FeO to MgO in the RO phase. When x ≥ 1 .5, the RO phase could not be hydrated after autoclaving at 215 °C and 2 MPa for 3 hours. The RO phase was blended into cement to study the relationships among the expansibility and composition and content of the RO phase via an autoclave test. When x ≤0.5, more than 5 pct of the RO phase cracked the specimen. When 0.5

The influences of aggregate combination and inhibitor additives on the Alkali-silica Reaction (ASR) were studied in this research. A long-term alkali activity simulation of fully-graded concrete also was carried out. The results showed that replacement of artificial sandstone sand with artificial marble sand reduced the alkali activity expansion rate of the sandstone aggregate and effectively improved the inhibition effect of the aggregate when mixed with 35 % fly ash. Activated silica in the fly ash was crushed into particles and was mixed into each part of the concrete system. It transformed the limited parts into unlimited active centers. As a result, each center participated in the reaction and consumed the alkali. Inhibition of the ASR was effective when the fly-ash content of the ASR-1 was 15 %, while in the ASR-2, the fly-ash did not have a significant inhibition effect. During a long-term simulation, the expansion rate of theconcrete specimens after standard curing at 20 °C was higher than was the expansion rate after outdoor natural curing. The expansion rate of full sandstone concrete specimens was higher than was that of sandstone specimens that contained marble stone.

Volumetric energy density is considered a primary factor in developing high-energy batteries. Despite its significance, less efforts have been devoted to its improvement. Silicon-based materials have emerged as next-generation anodes for lithium-ion batteries due to their high specific capacity. However, their volumetric capacities are limited by the volume expansion rate of silicon, which restricts mass loading in the electrodes. To address this challenge, we introduce porous silicon templated from earth-abundant minerals with native internal voids, capable of alleviating volumetric expansion during repeated cycles. In situ transmission electron microscopy analysis allows the precise determination of the expansion rate of silicon, thus presenting an analytical model for finding the optimal content in silicon/graphite composites. The inner pores in silicon reduce problems associated with its expansion and allow higher silicon loading of 42% beyond the conventional limitations of 13-14%. Consequently, the anode designed in this work can deliver a volumetric capacity of 978 mAh cc

In order to predict volume changes of Nb 3 Sn coils during reaction heat treatment (RHT), coefficients of thermal expansion (CTE) of the involved materials need to be known. While the CTEs of bulk materials are widely available, there is a lack of knowledge about the dimensional changes of the Nb 3 Sn Rutherford cables. By extensometry we have measured the length changes of 11 T dipole Nb3Sn Rutherford cables during the RHT. Similar to the length change behavior of multifilament wires, after an initial cable length increase the cable length decreases when the temperature exceeds about 150 °C, due to relaxation of the Nb subelements when the Cu matrix is annealed. At higher temperatures the cable length increase is determined by the CTE of the unreacted Nb, before the onset of Nb 3 Sn formation leads to an increased expansion rate. During cooling, the thermal contraction of fully reacted Nb 3 Sn cable is similar to that of Nb 3 Sn bulk.

ANFO is a well-known, reliable and safe commercial explosive. It has been around since the late 1950's and its detonation properties are well characterized. In this study, the detonation process of dry, wet and aluminised ANFO, was recorded using two high-speed cameras with recording rates of 1,200 fps and 50,000 fps. The 1,200-fps footage allowed the observation of the post blast fumes (i.e. NOx) produced by ANFOs with different water contents. The 50,000-fps footage allowed the observation of the detonation area, gas expansion phase and the measurement of the velocity of detonation (VOD). The video footage also recorded a bright zone in front of the gases (longer than 50 mm). We assumed that a reaction is taking place in this zone, but it is difficult to be sure if this is the reaction zone or not as it is longer than previously reported reaction zone lengths.Analysis showed that ANFO detonates effectively for water contents of up to 9 wt.%, and more importantly, there is little variation in the VOD. As far as the expansion of gases is concerned, the ANFO-Al expansion rate appears to be different. In this mixture, the absence of NOx fumes could have been due to the expected higher temperatures produced by the burning of the aluminium additive as observed in the images recorded with the high-speed camera.

The fatigue-crack growth of the die-forged Al-5.87Zn-2.07Mg-2.42Cu alloy at different ageing conditions: peak aged (T6), over aged (T73) and retrogression and re-ageing (RRA), has been examined in the study. The RRA alloy has the highest resistance to fatigue crack initiation. With increasing stress intensity range (Δk), the T73 sample has the largest expansion rate and it is the smallest for the RRA sample. In the second stage of crack propagation, the crack-growth rate is the largest for the T6 specimen and smallest for the RRA specimen. The crack propagation mode of the alloy in different ageing conditions is mainly based on transgranular expansion. Intergranular expansion was also observed in the T73 state and significant secondary cracks were observed in the RRA sample.

The results of experimental studies on determination of the effect of the deflector-type sprinkler geometric parameters on the air-mechanical foam formation process are presented in the article. A collapsible sprinkler was developed for the experiment. The elements of the collapsible sprinkler which allow creating its various configurations in a fairly wide range of geometric parameters were made from polylactide (PLA-plastic) with the help of 3D printing. The dependencies of the air-mechanical foam expansion rate and stability on the sprinkler holder length, as well as the external diameter, the taper angle and the ledges height of the sprinkler sprayer were established. The ranges of optimal values along the holder length L = 45÷55 mm and the sprayer ledges height h = 1÷3 mm of the sprinkler for generation of foam with the greatest expansion rate and stability were determined, as well as the ranges of values of these parameters at which the change in the quality characteristics does not occur (L = 90÷150 mm, h = 5÷15 mm). A decrease in the foam quality characteristics with an increase in the sprayer taper angle of the sprinkler was established. Approximate dependencies of the foam expansion rate and stability on the sprayer taper angle of the sprinkler in the range α = 30÷135° were obtained. In addition, it is determined that an increase in the sprayer external diameter in the range from 20 mm to 100 mm results in a gradual deterioration in the foam qua lity. The results of the conducted researches will allow optimizing geometrical parameters of existing designs of deflector-type sprinklers with the aim to increase their fire extinguishing efficiency.

Theoretical and experimental investigations are conducted to study the freezing process of a sessile water droplet. A novel model that considers the effects of both supercooling and gravity and assumes the freezing front (ice-water interface) to be a spherical surface is developed to simulate the droplet freezing behaviors. Two correlations describing the evolution of triple-phase line height and that of contact angle of unfrozen ice-water mixture on frozen ice are developed to close the model, with their concrete expressions being determined by combining the theory and experiment. Experiments are conducted on different sizes of water droplets deposited on cold aluminum plates having different contact angles and temperatures. The droplet freezing behaviors including the triple-phase line movements and droplet shape evolutions are observed and recorded using the image recognition technology. Calculations are implemented to simulate the evolution of droplet freezing shape, the movement of freezing front, the formation of pointy tip, and the variations of droplet volume and expansion rate. Comparisons are made between the calculation and experiment, and good agreements are obtained, with the calculated freezing times agreeing with the measured ones within 2%.

This paper studies the influence of assembly unit of expansive agents (CaO and calcium sulphoaluminate) on the limited and free compressive strengths, the limited expansion rate, carbonation resistance, chloride ion penetration resistance and corrosion resistance of reinforcement concrete. The dosages of expansive agent were 0%, 3%, 6%, 9%, and 12% by the total amount of cementitious materials. Two kinds of mineral admixture (blast furnace slag and fly ash) were applied in this study. Results show that suitable dosage (lower than or equal to 9%) of double expansion agent with a large amount of mineral admixtures can improve the limited and free compressive strengths. However, when the dosage of the double expansion agent is higher than 9%, the addition of the double expansion agent leads to the reduction of limited and free compressive strengths. The variation of the limit expansion rate reaches the maximum value when the curing age is 14 days. The increasing addition of expansive agents and lower water-binder ratio demonstrate positive effect on the limited expansion rate. Concrete with 60% mineral admixtures (fly ash and ground granulated blast furnace slag) shows lower limited expansion rate and higher compressive strength than the concrete with 50% mineral admixtures. Finally, the incorporation of double expansion agent can improve the resistance to carbonation, chloride ion penetration resistance, anti-corrosion of steel bars and mechanical strengths (the limited and free compressive strengths).

The transformation law of autogenous volume deformation of MgO-admixed concrete with specimen size was revealed through continuous observation on standard-size (Φ200 mm × 500 mm), medium-size (Φ250 mm × 500 mm), and large-size specimens (Φ250 mm × 600 mm) over 6 years. Besides, the pore parameters of concrete core samples obtained from autogenous volume deformation specimens in the 1st, 3rd, and 6th years of age were investigated. The results show that the autogenous volume deformation of MgO-admixed concrete increases with the increase in the MgO content or age. The expansion rate of the concrete specimen decreases after the age of 360 days, and the autogenous volume expansion deformation of the specimen tends to be stable after about 2 years. When the size of the specimen changes, the autogenous volume deformation of MgO-admixed concrete decreases with the increase of specimen size. During the age of 2–6 years, the expansion of medium- and large-size specimens is reduced by 6–10 and 15–20%, respectively, compared with the standard-size specimens under the same MgO content. With the condition of an appropriate MgO content, regardless of the size of the specimen, the pore structure of the concrete becomes better and better with the growth of age, the concrete becomes denser and denser, and the expansion caused by MgO hydration will not cause damage to concrete structures.

The stability of steel-slag road materials remains a critical issue in their utilization as an aggregate base course. In this pursuit, the present study was envisaged to investigate the effects of fly ash on the mechanical properties and expansion behavior of cement-fly-ash-stabilized steel slag. Strength tests and expansion tests of the cement-fly-ash-stabilized steel slag with varying additions of fly ash were carried out. The results indicate that the cement-fly-ash-stabilized steel slag exhibited good mechanical properties. The expansion rate and the number of bulges of the stabilized material reduced with an increase in the addition. When the addition of fly ash was 30&ndash, 60%, the stabilized material was not damaged due to expansion. Furthermore, the results of X-CT, XRD and SEM-EDS show that fly ash reacted with the expansive component of the steel slag. In addition, the macro structure of the stabilized material was found to be changed by an increase in the concentration of the fly ash, in order to improve the volumetric stability. Our study shows that the cement-fly-ash-stabilized steel slag exhibits good mechanical properties and volumetric stability with reasonable additions of fly ash.

In this study, the bit-level table of orthogonal test is adopted as the coding form of Genetic Algorithm (GA), and a Back Propagation (BP) neural network prediction model of the basic properties of full steel slag aggregate concrete (FSSAC) is established, and the experiment data are validated with good agreement. The impacts of several parameters including the sand ratio, water-cement ratio, content of steel slag sand, replacement particle size of steel slag sand, content of coarse steel slag, and replacement particle size of coarse steel slag on the compressive strength and expansion rate of the FSSAC are numerically investigated. The results show that the compressive strength of the FSSAC declines with the increase of the sand ratio, water-cement ratio, content of the steel slag sand, or coarse steel slag while it first increases and then decreases as the replacement particle size of steel slag sand or replacement particle size of coarse steel slag increases. The expansion rate of the FSSAC increases as the sand ratio or content of coarse steel slag increases. With a gradual increase of the water-cement ratio, content of steel slag sand, replacement particle size of steel slag sand, or replacement particle size of coarse steel slag, the expansion rate of the FSSAC first increases and then decreases. In addition, the impacts of the three most important parameters (i.e., water-cement ratio, content of steel slag sand, and replacement particle size of steel slag sand) on the stress-strain relationship of the FSSAC stub columns is further numerically studied.

This test method covers the laboratory determination of the expansion rate of concrete cores (designated as “residual expansion potential” in the following context) extracted from structures affected by alkali silica reactions.

In this study, the characteristics of the alkali-silica reaction (ASR) expansion of steel slag itself, mortar bars, and concrete specimens using steel slag as aggregate are individually investigated by the expansion test method, to determine if steel slag aggregate in concrete can provide volume stability. The results show that when steel slag is aged in water for one month, its self-expansibility is below the permitted limit of 1.5% according to the JIS A 5015 standard. The ASR test results show that the ASR expansion of the mortar bars continuously increased with the increase in the test period. However, all mortar bars were below the permitted limit of 0.1% after 14 days according to the ASTM C 1260 standard. In contrast, the ASR expansion of concrete specimens was above the criteria prescribed by the ASTM C 1293 standard. From the results, the expansion of concrete specimens could not be controlled within the permitted limit by the ASTM 1293 criteria, even if the expansivity of steel slag did not exceed the criteria. Meanwhile, considering the crack propagation patterns of the concrete specimens, the cracks due to ASR expansion developed and connected even when the expansion was below the permitted limit. Besides, when mineral admixtures were used as the binder in the concrete specimens, there were discrepancies in the results between the expansion rate and the crack properties, such as maximum length and total crack length. Therefore, to accurately determine the change in volume due to ASR expansion in concrete using steel slag as coarse aggregate, it is necessary to check the crack patterns in addition to evaluating the expansion rate.

This study was designed to clarify the relation between the pressure resistance of an angiographical tube and the amount of contrast medium injected under a connected microcatheter used for interventional radiology (IVR). We investigated the injection pressure and the expansion rate at the center of the tube during contrast enhancement by setting the power injector to 1200 PSI pressure, with 2.0 ml/s injection speed, 10 ml injection volume, 5.0 s injection time, and 0 s rise time for tubes with different pressure resistance performance (low or high). Then we examined the amount of contrast medium material discharged from the microcatheter. The low-pressure resistant tube (less than 140 PSI) injection pressure exceeded the pressure performance. The expansion rate increased to 49%, presenting a risk of rupture. The injection pressure of the high-pressure resistant tube (less than 1200 PSI) was within the pressure-resistance performance. The expansion rate increased to 38%. However, when the contrast medium discharge amount contributing to the image was measured within the injection time under the condition of 10 ml injection for 5.0 s, the former was 2.3 ml and the latter was 4.2 ml. The entire amount was not discharged during the injection period. It became apparent that it is discharged in drips after some time. Results show that the tube expansion caused retention of the contrast medium inside, which decreases the actual amount of the injected contrast medium. From the results, we infer the possibility of preventing reduction of the injected contrast medium amount attributable to expansion.

In order to accelerate the application of magnesium oxide (MgO) expanding admixture in roller compacted concrete (RCC), aiming at common three-grading RCC used in water conservancy and hydropower engineering, the autoclave expansion of mortar specimens and the compressive strength of the autoclaved mortar specimens were studied by means of autoclave test and compressive strength test. Results showed that the balanced MgO content in RCC, which cannot be determined by the MgO content corresponding to 0.5% autoclave expansion rate of mortar specimens or the inflection point of the curve of autoclave expansion changing with MgO content like normal concrete, should be determined by the MgO content corresponding to the inflection point of the curve that compressive strength of autoclaved mortar specimens changes with MgO content to ensure long-term safe operation of RCC dams.

We consider the fluid splitting dynamics of a small fluid drop entrapped between two parallel solid plates, which are rapidly pulled apart such that a free liquid sheet is formed between them for a few milliseconds. Velocities, time scales and shear rates correspond to the lift-off of a printing cylinder from the substrate in an industrial printing process. The formation and collapse of the liquid sheets, and the filaments forming at their rim are studied. Driven by the surface tension of the liquid sheet, the filaments are accelerated towards each other, and finally collide and decay. We show that surface waves that travel on the liquid sheet have a critical impact on this collision, which may either result in a smooth unification or in a highly dynamical collapse, ending in a random emission of fluid drops. Furthermore, we discuss the relevance of the Laplace number on the propagation of these waves. We also consider the liquid sheet decay by capillarity-driven expansion of spontaneously forming holes and discuss how sheet thickness and its local variation can be detected by an anisotropic hole expansion rate measurement.

Incorporating solid waste into cement and concrete products can save natural resources and reduce environmental problems caused by the disposal of industrial solid waste. In this study, steel slag powder and waste glass powder were synergistically used to replace cement. The blended cementitious materials showed good mechanical strength and autoclave stability with the synergistic aid of steel slag and waste glass. This study used an autoclave experiment to accelerate the hydration reaction. Results suggested that waste glass as an amorphous siliceous material enriched hydration products and completely consumed f-CaO in steel slag under autoclave for 3 h. The expansion rate of the blended paste was the lowest, and the stability was the best when the mass ratio of ordinary Portland cement: steel slag powder: waste glass powder was 7:2:1. A complete reaction of f-CaO occurred in the steel slag in the presence of an excess of waste glass powder in the blended cementitious materials. An excessive waste of glass powder can cause alkali–silicon reaction with Na+ and K+ ions and lead to expansion.

The application of an environmentally friendly modifier-superhydrophobic nano-silicon dioxide (SiO2) on improving the geotechnical characteristics of expansive soil is explored to examine the effect of different percentages of superhydrophobic nano-SiO2 (0.2 %, 0.4 %, 0.6 %, 0.8 %, and 1.0 % by weight of the parent soil) on soil expansion, shrinkage, permeability, and unconfined compressive strength (UCS). Two types of samples, unmodified soil (without nano-SiO2) and modified soil (with nano-SiO2), were used. Results revealed that the shrinkage rate, the Expansion rate, and permeability decreased for the soil samples modified with different contents of superhydrophobic nano-SiO2 and the UCS increased. The shrinkage rate decreased from 3.8 to 2.2 %. The minimum expansion rate of the soil samples modified with superhydrophobic nano-SiO2 was a quarter of that of the unmodified soil. Permeability decreased gradually from 1.38 × 10−8 cm/s to 6.25 × 10−10 cm/s as the superhydrophobic nano-SiO2 content increased. The peak UCS (647 kPa) of modified soil increased by almost 212 % compared with that of the unmodified soil. Superhydrophobic nano-SiO2 helped improve the geotechnical characteristics of expansive soil. In the shrinkage and unconfined compressive tests, 0.6 % nano-SiO2 content had a better effect on the modified soil. In the unloaded expansion and permeability test, the expansion rate and permeability decreased as the nano-SiO2 content increased. After the nano-SiO2 content reached 0.6 %, the decreasing speed became slow. The expansion rate and permeability were similar when the nano-SiO2 contents were 0.6 %, 0.8 %, and 1.0 %, respectively. Therefore, the optimum superhydrophobic nano-SiO2 content was 0.6 %.

Both the self-excited vibration of the wheel-rail system and the feedback vibration of track irregularity have certain effects on the rail corrugation. The present paper focuses on the effects of wheel-rail friction self-excited vibration and feedback vibration of corrugated irregularity on rail corrugation. Taking the typical rail corrugation on the low rail of the small-radius curve of the metro as the research object, the relevant wheel-rail finite element model and the worn rail surface of corrugated irregularity are established. Then, considering the influences of the wheel-rail friction self-excited oscillation and feedback vibration of corrugated irregularity, the stability and dynamic response of wheel-rail system on smooth and worn rail surfaces are studied to explore the dynamic origin of rail corrugation. Furthermore, the effects of the friction coefficient, corrugation depth and corrugation wavelength on the development of rail corrugation are studied, respectively. The results show that the wheel-rail friction-induced vibration may cause the rail corrugation and the feedback vibration of corrugated irregularity may aggravate the development of the subsequent rail corrugation. Then, the increase of the wheel-rail friction coefficient will increase the possibility of rai corrugation whether the rail surface is smooth or wear. When the wheel-rail friction coefficient is less than 0.2, no unstable vibration occurs. Moreover, the development of wear depth and the expansion rate to the surrounding rail of subsequent rail corrugation will be further intensified with the corrugation depth increases. Furthermore, when a corrugation wavelength is less than 60 mm, the feedback vibration of rail corrugation will aggravate the development of rail corrugation. Otherwise, the development rate of rail corrugation will gradually slow down with the corrugation wavelength increases continuously.

The effect of compressive strength and expansion rate of filler grout on bond behavior of grouted pipe splice is discussed. Three types of grout were designed and utilized to prepare coupler specimens as filler material. The compressive strength ranged from 67.5 to 91.8 MPa. The volume expansion rate changed from -0.023% to -0.037% under airtight curing condition, and from 0.027% to 0.057% under water curing condition, respectively. Based on pullout test, it was found that the bond strength and stiffness of grouted splice both improve with the increment of the expansion rate due to the increased initial confinement. By experimentally measuring the exterior surface transverse strain of grouted sleeve in curing stage, the confinement and its influencing factor on bond performance were derived. The confinement increases nonlinearly with the increment of grout shell thickness and sleeve radial stiffness other than grout expansion rate. The diameter-thickness ratio of sleeve should not exceed 13 to avoid a possible debonding failure at bar-grout interface. Utilizing the calculated confining pressures, the bond strength of the grouted splice was determined and compared with pullout test result, which shows a good agreement.

Purpose. Differentiation of constructive foam-forming factors, namely the ejector and the sprinkler deflector, influencing the expansion rate of the obtained air-mechanical foam in automatic firefighting installations. Methods. Conducting an experimental study of the process of formation of low expansion air-mechanical foam with sprinklers of various designs. Findings. The design of the sprinkler ejector with a cylindrical flowing path performs a preaeration of the extinguishing agent by only 12 % less efficient than the ejector made on the Venturi principle. It was found that the mechanical disintegration of the foaming solution flow on the sprinkler deflector has the greatest effect on increasing the expansion rate of the air-mechanical foam (the expansion rate increases by an average of 158 % in various sprinkler designs in the presence of the deflector). It is determined that as the distance of the element is increased, which ensures the splitting of the jet of the foaming solution, the expansion rate of the foam is increased. Thus, when the disintegration element of the flow (the bottom of the measuring container) was installed at a distance of about 50 cm from the deflector, the expansion rate increased by an average of 161 % compared to the values obtained when this element was installed at a distance of 3-4 diameters of the deflector of the sprinkler. Application field of research. The obtained results of experimental study can be used to improve the efficiency of firefighting with sprinklers in foam automatic firefighting installations. Conclusions. The effectiveness of preaeration of the extinguishing agent has been confirmed. The effect of individual structural elements of modern sprinklers on the expansion rate of air-mechanical foam is established. It is determined that the greatest contribution to the increase of expansion rate is brought by the desintegration of the flow of the foaming solution on the sprinkler deflector. Consequently, by modeling the surface of the deflector, the way it is fastened and positioned, it is possible to achieve values of the foam expansion rate K = 10–15 even without the effect of preaeration. To determine the influence of the geometry of the deflector, the method of its fastening and positioning with respect to the sprinkler, additional theoretical and experimental studies are required.

This study investigated the effects of ultrasonic on the quality of puffed cowhide and of ultrasonic treatment on various parameters, such as color, expansion rate, microstructure, texture, and sensory score. Under all experimental conditions, ultrasonic significantly improved the quality of puffed cowhide. Ultrasonic was used to treat the puffed cowhide at 210°C, at which the highest expansion rate, L*, and sensory acceptability are obtained. At this temperature, hardness, and masticatory properties obtained the minimum values. Moreover, the product's microstructure showed uniform bubbles, and the overall acceptability was high, thereby resulting in the optimal quality of the product. In addition, puffing rate and sensory evaluation were negatively correlated with hardness and chewiness, and the sensory evaluation was positively correlated with L*, ΔE, and puffing rate. Therefore, ultrasonic is an effective method for improving the quality of puffed cowhide. PRACTICAL APPLICATIONS: Ultrasonic processing is increasingly used in food technology. Through ultrasonic treatment, this study successfully solved the low expansion rate and poor coloration in puffed cowhide and found that cowhide can be recycled after slaughter. Ultrasonic‐treated puffed products exhibit bright color, high expansion rate, reduced hardness, and favorable chewiness and contain collagen that promotes health. These findings demonstrated that ultrasonic treatment significantly improves the quality of puffed cowhide.

Using rice flour and Agaricus bisporus powder as raw materials, a puffed snack was developed by twin‐screw extrusion technology. The Box–Behnken design method was used to optimize the process variables with three factors in three levels. The experimental variables were included temperature (135°C–155°C), moisture (13%–17%) and the addition amount of A. bisporus powder (3%–7%). The extrudate properties were evaluated by determining the expansion ratio. The optimization results indicated that the extrusion temperature was adjusted to 149°C, the moisture content of raw materials was 14.4%, and the addition of A. bisporus powder was 4.2%. Under these conditions, the expansion rate of the product was up to 3.41. The obtained extruded snacks had good taste, high expansion ratio and loose porosity. Compared with snacks without A. bisporus powder, the puffed snacks had better characteristics (high consumer tasting score, relatively low hardness). PRACTICAL APPLICATIONS: After making the puffed snacks, fruits and vegetables were easy to store and transport and enrich the products of A. bisporus. The puffing rate, consumer evaluation and hardness of A. bisporus snacks were studied, which provided a theoretical basis for optimizing the processing characteristics of A. bisporus. Agaricus bisporus and rice flour provided great space for the development of puffed food.

A method is proposed for the calculation of bulk viscosity, μ_{b}, of dilute gases using nonequilibrium molecular dynamics (NEMD) simulations. The method uses measurement of mechanical (P_{mech}) and thermodynamic pressure (P_{thermo}) in a NEMD simulation of an expanding fluid and then relates the bulk viscosity to them by the relation μ_{b}=(P_{mech}-P_{thermo})/∇·u[over ⃗], where ∇·u[over ⃗] is the controlled rate of expansion of the fluid per unit volume. A special emphasis is given to the fundamental physical understanding of bulk viscosity in this work. The proposed method is demonstrated for the estimation of bulk viscosity of dilute nitrogen gas in the temperature range of 200-800 K. Variation of bulk viscosity with temperature is reported in the above-mentioned temperature range and is found to be in a reasonably good agreement with the data available in the literature. Furthermore, variation of bulk viscosity with pressure and volumetric expansion rate is obtained. A weak linear dependency of bulk viscosity with pressure is observed, which increases with temperature. However, no significant effect of the rate of volumetric expansion is observed until 10^{8}s^{-1}. Moreover, the effect of the direction of volumetric change (expansion vs. compression) is also demonstrated in this work.

Foamed concrete is a heat preservation and noise reduction material made of cement and aluminum powder as foaming agent. The experiment mainly studies the influence of different water-cement ratio, foaming agent dosage and cement dosage on the expansion rate of foamed concrete test block. The experimental results show that when the water-cement ratio increases from 0.4 to 0.6, the expansion rate decreases gradually. When the content of aluminum powder foaming agent increased from 0.05% to 0.40%, the expansion rate showed a trend of “increasing first and then decreasing”. When other conditions are the same, the expansion rate of cement increases from 500kg/m3 to 800kg/m3, showing a trend of “decreasing first and then increasing”.

This article evaluated the effect of improved autogenous mortar self-healing in the alkali-aggregate reaction (AAR). Prismatic mortar specimens were cast with different contents of polypropylene microfiber and crystalline admixture. The crack-induction method (for subsequent self-healing) was the AAR accelerated mortar bar test itself. After AAR-testing, the specimens were submitted to wetting and drying cycles to stimulate the self-healing mechanism. These two approaches (AAR and self-healing steps) were alternately repeated four times. The results showed that the reference mortar and the mixture with 1% of polypropylene microfiber had the highest and lowest levels of expansion, respectively. The expansion rate was lower for the combined mixtures, although the initial values of length change were high. The visual inspection confirmed that improved autogenous self-healing could close cracks caused by AAR and promote microstructural densification.

This study applied autoclave expansion and heat curing to accelerate the hydration of concrete and investigated how these methods affect the expansion rate, crack pattern, aggregate size effect, and expansion of electric arc furnace oxidizing slag (EOS)-containing concrete. An expansion prediction model was simulated to estimate the expansion behavior over a long period and to establish usage guidelines for EOS aggregates. The results showed that the EOS content in concrete should range between 20% and 30% depending on the construction conditions, and that coarse aggregates with a diameter of

An expandable thermal insulation material was prepared which can expand the volume at high temperature. The paper is aimed to study the effect of the particle size of expandable graphite for this material, through comparing properties including expansion rate, compression strength and heat conductivity coefficient. The material with 200 mesh has the lowest expansion rate, but compression strength is the maximum 0.901MPa at 800°C while the lowest heat conductivity coefficients 0.118W/m·k at 1100°C which has a 25% reduction in the 50 mesh.

This study examined the quality characteristics of meringue cookies added with tomato powder (0, 5, 10, and 15%). The pH of dough significantly decreased with higher tomato powder content. Spreadability, loss rate, and expansion rate also decreased with higher tomato powder content. The lightness of meringue cookies significantly decreased with addition of tomato powder, whereas redness and yellowness increased significantly with addition of tomato powders. Hardness of meringue cookies decreased significantly with addition of tomato powder. 2,2-Diphenyl-1-picrylhydrazyl radical scavenging activities and total phenol contents significantly increased as tomato powder content increased. In the sensory evaluation, sensory scores for color, flavor, taste, and overall acceptability were highest in the 5% tomato powder meringue cookies. Thus, our results suggest that the optimum amount of tomato powder to add to cookies is 5%.

Wedding cake growth is a layer-by-layer growth model commonly observed in epitaxial growth of metal films, featured by repeated nucleation of new atomic layers on the topmost surface owing to the confinement of the Ehrlich-Schwoebel (ES) barrier. Herein, we report an inverted wedding cake growth phenomenon observed in two-dimensional nanostructure evolution. Through a dynamically controlled vapor-solid deposition process of ZnO, a unique basin-shaped crown was formed on the tip of each nanowire, featured with concentric steps. The atomic steps were nucleated along the edge and propagated toward the center. This is an opposite growth behavior compared to the conventional wedding cake growth, and is thus denoted as inverted wedding cake growth. Through the relation between the crown expansion rate and the temperature, the ES barrier of ZnO was determined to be 0.88 eV. The discovery of inverted wedding cake growth provided insight into the developing nanostructure growth mechanisms.

The special attention in analysis of the sublayer extinguishing process was paid to results of full-scale tests. Low efficiency of the sublayer fire extinguishing system can be caused by a number of neglects which are allowed in processes of preparation and extinguishing. It is related to the choice of foaming agent, method of preparation of working solution, method of producing and transportation of foam, method of injection of foam into oil product. Some results of full-scale tests of the sublayer system during extinguishing of fires in tanks with oil or oil products, which were conducted on testing grounds of such cities as Perm, Novopolotsk, Astrakhan and Almetyevsk are presented in the article. It is also presented analysis of foreign information sources. On the basis of analysis of full-scale fire tests and comparison of obtained results, using model experiments, there were revealed the optimal parameters of the sublayer system in process of extinguishing of fires in oil tanks. Factors leading to decrease of fire extinguishing efficiency of the sublayer system are considered. The conclusion is that fire extinguishing efficiency of the sublayer system is decreased due to such factors as decrease of foaming agent concentration during preparation and storage of working solution, that affects spontaneous spreading of aqueous solution on the surface of oil product; an error in dosing of concentrated foaming agent in process of preparation of working solution; impossibility to obtain the foam with expansion rate not less than 3.5 using generators with consumption rate of more than 10 l/s and pressure (9+0.5) atm; application of foam generators with back pressure valve placed on air ejection line for creation the pressure necessary to open the valve and to rupture safety membrane; absence of a foam sampling procedure, while generator is working, which exclude capture of air by falling stream of foam; application of foam with expansion rate lower than 4.0; maintaining of optimal length of a foam line to obtain the foam with homogeneous structure; application of distributed scheme of foam nozzles location to prevent formation of local areas with raised layer of oil and to decrease the capture degree of foam by descending oil streams; providing the long period before burnback of oil product by heated tank walls due to loss of foam insulating properties.

The objective of this study is to clarify optimal conditions for suppressing the expansion of ASR-deteriorated concrete by pressure-injecting a lithium nitrite solution. To investigate the ASR-mitigating effect of lithium nitrite, concrete mixtures with two types of reactive aggregates were impregnated with lithium nitrite by pressurized injection at three steps of ASR. The effects of different timings on the penetration of lithium nitrite driven by the pressure gradient and on the suppression of expansion were examined through tests. The expansion rate started to decrease immediately after injecting a lithium nitrite solution into the concrete in the propagation period (PP) with severe ASR cracking and an expansion strain of 2000 micro. With a lithium-sodium molar ratio of 0.6 or more, further expansion was significantly reduced. On the other hand, expansion continued even after application of lithium nitrite when the solution was injected into the concrete in the early propagation period (EPP) with slight ASR cracking and an expansion strain of 400 micro, and the final strain eventually exceeded that of the concrete that had been subjected to the lithium injection in the PP. It is assumed that the lithium nitrite solution migrates through ASR cracks first because of the pressure gradient and then diffuses into the bulk mortar. The degree of expansion could also be affected by at which stage of ASR the lithium ions reach the reactive aggregates and the ASR gel.

According to the Fire Statistics Yearbook of the National Fire Agency of the Republic of Korea, the total number of fires in 2018 was 42,338, which resulted in 2500 victims and amounted to property damages of approximately 560 billion KRW. The number of fires in buildings where wood was used as a finishing material was 28,013 (66%) in that period. To minimize human and property damage, composite materials were prepared by mixing wood particles with expandable graphite. The physical and thermal properties of the composite materials were investigated. It was observed that the expansion rate increased by 341.7% according to the expandable graphite content. Additionally, the total heat released and the thermal conductivity decreased from 38.63 to 2.5 MJ/m2 and from 24.62 to 7.8 W/m&middot, K. The time to inactivity of white mouse in the smoke toxicity test was 14.9 min and exceeded the toxicity standard for flame retardant performance. The expandable graphite added to composite materials adopted worm-like shapes as a result of combustion, and it formed a fine lattice layer structure with 16&ndash, 22 &mu, m gaps that could reduce thermal conductivity. In addition, we can minimize the damage to people and property in the event of a fire.

The introduction of Fan-Out Wafer-Level Packaging (FOWLP) is one of the viable approaches as the current packaging technology is moving towards low cost, multi-functions and small form factor packages [1]. FOWLP also offers good interconnects due to its shorter inter-connections from the chips to the thin-coated layer of metallization [2]. However, warpage largely induced from molding compound becomes a challenge in the fabrication of the FOWLP [3]. Silicon die bonded onto the carrier and the die shifted from its original bonded position during encapsulation known as die shifting. Factors affecting the die shift can be from material expansion rate, dragging force during encapsulation and the mold compound shrinkage properties [4].In this paper, we evaluated 3 different configurations of FOWLP Mold-1st packages to study the impact of the configuration and process parameters on die shifting, and die protrusion during the assembly process. DOE incorporating different bonding force is done to study their impact and to achieve a die shift, and die protrusion target of $\pm 15 \mu \mathrm {m}$.In summary, we are able to achieve a small die shift, minimum die protrusion and minimum warpage on the molded wafer for this FOWLP fabrication study.

Laparoscopic surgery has the advantage of the minimally invasive for patients. However, the surgery is technically difficult for surgeon because high dexterity is required for suturing in the narrow patient's body. This paper presents a sealing method to locate the adhesive plaster at the incision instead of suturing. The objective is to optimize the plaster material and structure. We made the plaster with the thermally cross-linked gelatin film in a spiral fold because thermally cross-linked gelatin film has the high biocompatibility and tackiness, and a spiral fold has great storage efficiency. In 3 experiments, we measured expansion rate, expansion tension, peeling force, and sealing pressure in a variety of gelatin volume and concentration, and the films diameter. From these experimental results, we optimized the films using response surface method. As a result, the plaster is optimal at gelatin volume 10 mL, gelatin concentration 4 wt %, and films diameters 75 mm. We concluded that the optimized spiral folded adhesive plaster is sufficient in terms of the expansion, tackiness, and sealing properties.

Several failures of high-voltage and extra-high-voltage cable joints have been reported in China. It is postulated that improper pre-expansion of the cable joints before installation on the cables played a major role in the breakdowns. In this study, the researchers used two 110 k V silicon rubber premolded cable joints as experimental samples. They were subjected to different expansion rates before installation onto a cross-linked polyethylene cable cross-linked polyethylene. Two different specifications of expanding tube were used to expand the joints. Then, withstand voltage tests and partial discharge (PD) tests were done at room temperature and high temperature (95 to 100°C) according to IEC 60885–2. Statistical parameters and patterns were recorded during the test. The joint assembled with an improper expansion rate during pre-expansion installation failed to pass the PD test. The PD behavior was clearly affected by the voltage and temperature during the test. On the basis of these results, the authors propose recommendations for the installation of 110 kV silicone rubber premolded cable joints.

It is well known that the Alkali-Silica Reaction (ASR) expansion in concrete is influenced by the stress state of the material. However, the extent and nature of this influence is not completely understood due to the scarcity of experimental investigation under triaxial stress states. This paper presents experimental ASR expansion curves obtained from cubical concrete specimens subjected to three different triaxial stress states, by means of a new testing machine especially designed for this purpose. The results seem to confirm that the volumetric ASR expansion rate is reduced as the applied volumetric compressive stress is increased. Additionally, there seems to be an increase of the expansion rate in the less compressed direction in detriment of the expansion rates in the most compressed ones.

In order to study on uniaxial mechanical properties of silty-mudstone under impact of temperature and humidity, a series of uniaxial mechanical tests were carried out. According to these tests, uniaxial mechanical indexes (compressive strength, elastic modulus, splitting strength) of silty-mudstone under different temperature and humidity conditions were obtained, and based on which, its change rule was analyzed. The test results indicate that when considering temperature shift only, uniaxial mechanical indexes of silty mudstone exponential decrease with the increase of cyclic times under same mode of temperature shift, decrease with temperature difference under same cyclic times and direction of temperature shift. After soaking, expansion rate and water content of silty-mudstone increases rapidly at the early stage and tends to be gentle at the later stage, uniaxial mechanical indexes exponential decrease with the increase of water content. After simultaneous variation of temperature and humidity, uniaxial mechanical indexes increase with the increase of temperature difference under negative direction of temperature shift, decrease with the increase of temperature difference under positive direction of temperature shift. Under same conditions, compare influence on mechanical properties: simultaneous variation of temperature and humidity> humidity shift only> temperature shift only.

When using a controlled electrical breakdown [1, 2] in a plasma channel that is produced by an exploding wire [3, 4, 5, 6, 7, 8] and is capable of passing a current in the short-circuit mode, on should know the temperature and radius of the channel [9].

Detailed research is carried out to ascertain the inhibitory effect of waste glass powder (WGP) on alkali-silica reaction (ASR) expansion induced by waste glass aggregate in this paper. The alkali reactivity of waste glass aggregate is examined by two methods in accordance with the China Test Code SL352-2006. The potential of WGP to control the ASR expansion is determined in terms of mean diameter, specific surface area, content of WGP and curing temperature. Two mathematical models are developed to estimate the inhibitory efficiency of WGP. These studies show that there is ASR risk with an ASR expansion rate over 0.2% when the sand contains more than 30% glass aggregate. However, WGP can effectively control the ASR expansion and inhibit the expansion rate induced by the glass aggregate to be under 0.1%. The two mathematical models have good simulation results, which can be used to evaluate the inhibitory effect of WGP on ASR risk.

The composition and microstructure of microcrystalline graphite were studied by X-ray diffraction, differential thermal analysis–thermogravimetry, SEM and energy dispersive analysis in this paper. The chemical composition of ash in microcrystalline graphite was also analysed in the study. The microcrystalline graphite was introduced in MgO–C refractories fabrication to investigate the influence of microcrystalline graphite on the main properties of MgO–C refractories. The oxidation resistance, thermal shock resistance, hot bending strength and expansion rate of MgO–C samples with microcrystalline graphite and flake graphite were investigated in this study. It is indicated that the proper addition amount of microcrystalline graphite in MgO–C refractories should be no more than 4 wt-%.

A bioresorbable metallic helical stent was explored as a new device opportunity (magnesium scaffold), which can be absorbed by the body without leaving a trace and simultaneously allowing restoration of vasoreactivity with the potential for vessel remodeling. In this study, developed Mg-based helical stent was inserted and expanded in vessels with subsequent degradation in various environments including static, dynamic, and porcine ex vivo models. By assessing stent degradation in three different environments, we observed: (1) stress- and flow-induced degradation; (2) a high degradation rate in the dynamic reactor; (3) production of intermediate products (MgO/Mg(OH)2 and Ca/P) during degradation; and (4) intermediate micro-gas pocket formation in the neighboring tissue ex vivo model. Overall, the expandable Mg-based helical stent employed as a scaffold performed well, with expansion rate (>100%) in porcine ex vivo model.

Electron evaporation plays an important role in the electron temperature evolution and thus expansion rate in low-density ultracold plasmas. In addition, evaporation is useful as a potential tool for obtaining colder electron temperatures and characterizing plasma parameters. Evaporation theory has been developed for atomic gases and has been applied to a one-component plasma system. We numerically investigate whether such an adapted theory is applicable to ultracold neutral plasmas. We find that it is not due to the violation of fundamental assumptions of the model. The details of our calculations are presented as well as a discussion of the implications for a simple description of the electron evaporation rate in ultracold plasmas.

Aluminum foam sandwiches (AFS) were successfully prepared by a powder metallurgical method. TiH2 powders were pre-treated in air at 450°C and 500°C for 2h in order to clarify the effect of oxidation treatment on AFS in comparison to those as-received. The decomposition curves of as-received and oxidized TiH2 powders were monitored using DSC. The macro-morphology, expansion ratio, interfacial bonding and cell structure of AFS were systematically investigated. The results show that the AFS utilize TiH2 powders oxidized in air at 450°C for 2h exhibits the best performance, under which conditions the effective bonding between the panel and core, 200% of the expansion rate and uniform pore structure of AFS have been achieved.