Volume Replacement Method Research Articles

Study on preparation and performance of advanced aerogel foamed concrete with ultra-light aerogel

Aerogel foamed concrete has been acknowledged as one of the most promising energy efficient building materials with high thermal insulation performance and low density in applications of green buildings and nearly zero energy buildings. However, the practical economy of aerogel foamed concrete is still relatively poor because of the greater amount of high-price ultra-insulating aerogel additive needed in the foamed concrete. Therefore, based on the premise of maintaining the high thermal insulation performance and low density of foamed concrete, reducing the amount of aerogel additive has become a key issue to improve the economy and promote the application of high-performance aerogel foamed concrete. This study proposed an equal volume replacement method based on using an ultra-light SiO2 aerogel instead of conventional SiO2 aerogel to reduce the amount of aerogel additive in foamed concrete while maintaining a high thermal insulation performance and low density. Two kinds of aerogel foamed concrete were prepared by filling light density (170 kg/m3) and ultra-light density (75 kg/m3) adiabatic aerogel powder into foamed concrete. An experiment was conducted to study the influence of different aerogel densities on the thermal conductivity, compressive strength and density of foamed concrete. The research results indicate that the density and thermal conductivity can be effectively reduced by filling ultra-light aerogel powder compared with traditional aerogel foamed concrete with an acceptable compressive strength. The results also show that the mass dosage of aerogel can be significantly reduced by using ultra-light aerogel powder. Specifically, for a foam volume ratio of 70 % and aerogel volume ratio of 13 %, the density and thermal conductivity of the ultra-light aerogel foamed concrete were reduced by approximately 10 %, which resulted in a cost reduction of 49 %. By applying the ultra-light aerogel foamed concrete in the construction of an exterior wall of a building, the heat loss through the wall can be reduced by 9 %. This study provides a significant reference for the preparation of high-performance foamed concrete and accelerates the application of super adiabatic aerogels in the building energy conservation industry.

Preparation and Application of a Novel Slow-Releasing with Core-Shell Deicer in Asphalt Mixtures.

The massive application of chloride salts has a direct effect on the corrosion of structures and vehicles and decreases durability as well as road pavement damage. A novel slow-release deicer with a core-shell structure was prepared to reduce the salts’ impacts, subsequently characterized by scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS), differential scanning calorimetry (DSC), and thermogravimetric analysis (TG). The conductivity evaluation, moisture absorption, and the snow or ice melting performance of the deicer were also tested. The core-shell deicer with different replacement rates was used to prepare the deicing asphalt mixture based on the equivalent volume replacement method. In this study, the high- and low-temperature performance, moisture damage resistance, and snow or ice melting capacity of mixtures were evaluated in the laboratory. The results show that the low-temperature and moisture stability performances decreased, and high-temperature performance improved, as the content of the core-shell deicer was increased. It is confirmed that the replacement rate of the deicer filler should be lower than 75% to meet the specification requirements. The prepared deicing asphalt mixture has good snow and ice melting performance and can reduce the bonding strength between ice and pavement surface. Durability and cost–benefit analysis are expected in further investigations.

Study on mechanical properties of concrete inclusion of high-volume coal bottom ash with the addition of fly ash

Coal bottom ash (CBA) has been widely utilized in concrete production as a partial replacement for aggregate. Still, the massive amount of CBA generated every day ends up dumped at a landfill without economic value. Therefore, the aim of the study identified the influence of CBA as a coarse and fine aggregate replacement, in addition of fly ash (FA) as a partial cement substitution in concrete made. The experimental tests were carried out on the fresh and hardened state of concrete to evaluate the workability test, compression test, flexural test, and modulus of elasticity test. CBA was replaced in concrete by four different combination arrangements between half (50%) and full (100%) coarse and fine aggregate using the volume replacement method. Then, 20% of FA was substituted to the mass of cement as an additive cementitious material to enhance the pozzolanic reaction. The results revealed that a high amount of CBA in concrete contributed to the low workability of fresh concrete. The concrete made by 100% CBA as coarse and fine aggregate replacement produced better compressive strength than the control concrete. Besides, all replacement levels of CBA in concrete had a modulus of elasticity in the range of 5.07 to 5.67 GPa, which is acceptable for its compression strength of 30 to 35 MPa at 28 days. Besides, CBA concrete recorded a significant reduction in flexural strength with the increment level of percentage CBA in concrete mix ingredients. Therefore, the evaluation of the mechanical properties of concrete containing large volume CBA with the addition of FA shows good performance and has the potential to be utilized in concrete manufacturing.

Properties of high volume coal bottom ash in concrete production

Coal bottom ash (CBA) is a by-product of pulverized coal combustion that contributes to a large amount of industrial solid waste. Coal bottom ash has been frequently used in the manufacture of concrete as a partial substitute for cement and aggregate in recent years. Despite this, the enormous amount of coal bottom ash produced each day is disposed of in landfills without proper treatment. Thus, this study aimed to investigate the properties of the high amount of CBA in concrete manufacturing. CBA replaced in concrete as 50%, 60%, 70%, 80%, 90%, and 100% of fine and coarse aggregate replacement by using the volume replacement method. The tests carried out on concrete were fresh concrete workability and mechanical properties in terms of compressive strength, tensile strength, and flexural strength. After achieving all this strength, the correlation equations between each of the mechanical strengths were established. The results revealed that the high amount of CBA had the most influence on the slump reduction and weakest the flexural strength. Moreover, high volume usage of CBA material in concrete had achieved the targeted compressive strength at age 28 days of curing. The acceptable strength performance of concrete containing a high amount of CBA has potentially in the widespread use of this material in the construction industry.

Strategies for the selection of oncoplastic techniques in the treatment of early-stage breast cancer patients.

In recent years, breast cancer is the most common malignancy in women. The traditional method of surgery is to remove a woman's breast completely, which has a negative impact on her work and life. Today, women have a fiery pursuit to maintain their perfect figure, which has forced breast surgeon to find a new surgical approach to maintain the shape of the breast after surgery. This study systematically analyzed and summarized the incision design and repair of glandular defects in early-stage breast cancer patients by oncoplastic breast techniques. By summarizing the methods of oncoplastic breast surgery (OBS) in different quadrants, it could help beginners to master this technology more quickly, so as to provide better help for breast cancer patients. A total of 216 breast cancer patients who underwent OBS from January 2016 to June 2020 at the Affiliated Hospital of Guangdong Medical University were included in this study. In patients treated with the volume-displacement method and the volume-replacement method, 92.6% and 86.2% of patients achieved excellent breast shape, respectively. OBS is a safe and effective way to treat early-stage breast cancer while obtaining better breast shape, reducing postoperative psychological trauma, and improving quality of life.

Study on reinforcement mechanism and microscopic morphology of steel-basalt mixed fiber HPCC

To further improve the working performance of steel fiber cement-based composites, reduce the construction difficulty and explore the mechanism of mixed fibers in cement-based composites. Based on the single blending of steel fiber, the substitution rates of seven different basalt fibers are studied by the equal volume replacement method. And the microstructures of mixed fiber cement-based composites are studied by the method of environmental scanning electron microscopy (ESEM) and by using Image-Pro Plus (IPP). Results show that when the fiber replacement rate reaches 20%, the positive hybrid effect of the two fibers are the best for the cement-based composites. The splitting tensile strength of the mixed fiber cement-based composites also reaches the maximum value of 20.07 MPa, which is 110% of the corresponding strength of the single-doped steel fiber, and the working performance is also greatly improved. In microscopic view, a reasonable mixing of fibers can effectively improve the internal structure of the matrix and enable the pores to be smaller and more uniform than before. At the same time, the fiber-reinforced crack resistance effect can greatly improve the deformation resistance of the matrix, so that the matrix can still maintain a good integrity in the final destruction. The main factors affecting the macroscopic mechanical properties of the mixed fiber cement-based composite are found by grey correlation, which essentially reveals the influence of the changes in fiber content on the macro-performance of the matrix. The results provide a foundation for the research and application of mixed fiber cement-based composites.

Strength and Stiffness of Recycled Concrete Aggregates

As the construction is in its highest pace, the demand of raw material especially coarse aggregate is in great demand. At the same time the renovation, demolition and refurbishing of old structures is a continuous process, it is resulting in significant source of recycled concrete aggregate (RCA). Bit uncertainty and great variation in properties of RCA has restricted its wide use in all engineering construction activities. From point of view of conservation of natural resources, use of recycled concrete aggregate reduces use of natural aggregates, utilization of waste and results in energy saving. Thus extensive study is carried out to ascertain the effects of use of recycled concrete aggregate (RCA) on strength and stiffness of concrete. The rejected precast concrete, unused ready mixed concrete and concrete from demolished old structures is considered for RCA. Compressive strength and stiffness gain tests are conducted for both natural and recycled concrete aggregate (RCA) is carried out and the results are presented in this paper. Direct volume replacement method is used for replacing a selected quantity of natural coarse aggregates (NCA) by an equal volume of recycled concrete aggregate (RCA).

Study on the Correlation between the Texture Depth of Volume Replacement Method and the Texture Depth of Spectral Reproduction Method

Through theoretical research and actual road condition analysis, this paper establishes the simulation calculation model and the spectrum analysis model. Through the spectrum inversion, the stable road surface state is obtained, and the conversion relationship between the reconstruction depth of the spectral reproduction method and the structural depth of the volume displacement method is obtained. Through the conversion relationship of a typical single spectrum, the relationship between SMTD and TD is obtained under each type of standard waveform. Actually, in the process of sand paving, due to the presence of the exposed part, the SMTD and TD in the actual road surface are not positively correlated, thereby correcting the relationship between SMTD and TD. The acquired road surface data is modeled by MATLAB, and the analog waveform is made according to the actual waveform, and the reduced order decomposition is performed to determine the range of a. The intercept b value is determined by comparing the experimental spectra before and after sanding. This paper solves the problem that the detection mechanism needs to perform statistical correlation test in accordance with the requirements of JTG-E60 regulations to meet the requirements of pavement assessment.

Strength Time–Varying and Freeze–Thaw Durability of Sustainable Pervious Concrete Pavement Material Containing Waste Fly Ash

Pervious concretes, as sustainable pavement materials, have great advantages in addressing a number of environmental issues. Fly ash, as the industrial by-product waste, is the most commonly used as cement substitute in concrete. The objective of this paper is to study the effects of waste fly ash on properties of pervious concrete. Fly ash was used to replace cement with equivalent volume method at different levels (3%, 6%, 9%, and 12%). The control pervious concrete and fly ash modified pervious concrete were prepared in the laboratory. The porosity, permeability, compressive strength, flexural strength, and freeze–thaw resistance of all mixtures were tested. The results indicated that the addition of fly ash decreased the early-age (28 d) compressive strength and flexural strength, but the long-term (150 d) compressive strength and flexural strength of fly ash modified pervious concrete were higher than that of the early-age. The adverse effect of fly ash on freeze–thaw resistance of pervious concrete was observed when the fly ash was added. The porosity and permeability of all pervious concrete mixtures changed little with the content of fly ash due to the use of equal volume replacement method. Although fly ash is not positive to the properties of pervious concrete, it is still feasible to apply fly ash as a substitute for cement in pervious concrete.

Laboratory Evaluation of Eco-Friendly Pervious Concrete Pavement Material Containing Silica Fume

Pervious concretes, such as sustainable pavement materials, have great advantages in solving urban flooding, promoting urban ecological balance, and alleviating urban heat island effect, due to its special porous structure. However, pervious concrete typically has high porosity and low strength. The insufficient strength and poor freeze-thaw durability are important factors that restrict its wide application, especially in seasonal frozen areas. Improving the strength and freeze-thaw resistance of pervious concrete will expand its application. Silica fumes, as an industrial by-product waste and supplementary cementitious material, play an important role in improving concrete performance. The objective of this paper was to study the effects of silica fumes on properties of sustainable pervious concrete. Silica fumes were used to replace cement with the equivalent volume method at different levels (3%, 6%, 9%, and 12%). The control pervious concrete and silica fume-modified pervious concrete mixtures were prepared in the lab. The porosity, permeability, compressive strength, flexural strength, and freeze-thaw resistance properties of all mixtures were tested. The results indicated that the addition of silica fumes significantly improved the strength and freeze-thaw resistance of pervious concrete. The porosity and permeability of all pervious concrete mixtures changed little with the content of silica fumes due to the adoption of the equal volume replacement method.

Comparison of loess and purple rill erosions measured with volume replacement method

Summary Rills are commonly found on sloping farm fields in both the loess and the purple soil regions of China. A comparative study on rill erosion between the two soils is important to increase research knowledge and exchange application experiences. Rill erosion processes of loess and purple soils were determined through laboratory experiments with the volume replacement method. Water was used to refill the eroded rill segments to compute eroded volume before sediment concentration distribution along the rill was computed using the soil bulk density, flow rate, and water flow duration. The experimental loess soil materials were from the Loess Plateau and purple soil from the southwestern part of China, Chongqing City. A laboratory experimental platform was used to construct flumes to simulate rills with 12.0 m length, 0.1 m width, and 0.3 m depth. Soil materials were filled into the flumes at a bulk density of 1.2 g cm −3 to a depth of 20 cm to form rills for experiments on five slope gradients (5°, 10°, 15°, 20°, and 25°) and three flow rates (2, 4, and 8 L/min). After each experimental run under the given slope gradient and flow rate, the rill segments from the upper slope between 0–0.5, 0.5–1, 1–2, 2–3, …, 7–8, 8–10, and 10–12 m were lined with plastic sheets before be re-filled with water to determine sediment concentration after the eroded volumes was measured. Rill erosion differed between the two soils. As purple soil started to erode at a higher erosive force than loess soil, it possibly exhibits higher resistance to water erosion. The subsequent erosion process in the eroding purple rill was similar to that in the loess rill. However, the total erosion in the eroding loess rill was more than that in the eroding purple rill. The maximum sediment concentration transported by the eroding purple rills was significantly lower, approximately 55% of those transported by the loess rills under the same flow rate and slope gradient. Hence, less purple sediments can be transported compared with loess sediments. These findings were validated through comparison with existing studies. The results indicate that the research methods and experiences on rill erosion can be inter-exchanged between the loess and purple soils.

Laboratory investigation of andesite and limestone asphalt mixtures containing sodium chloride-based anti-icing filler

The research evaluates the effects and effectiveness of a sodium chloride-based anti-icing filler on andesite and limestone asphalt mixtures. The asphalt mixtures containing different amount of anti-icing fillers were designated based on the equivalent volume replacement method. In this study, the rutting susceptibility and low-temperature flexural properties, moisture susceptibility, anti-icing properties and snow melting capacity of mixtures were evaluated in the laboratory. The results showed that the specimens containing anti-icing fillers decreased their dynamic stability, flexural strain, residual Marshall stability ratio, and TSR values compared to those control ones. The mixtures made from two aggregate sources exhibit similar trends in general. It was also proved that the asphalt mixtures containing anti-icing fillers had anti-icing and snow melting capacity at a certain condition. In this research, it could be found that the replacement of anti-icing filler was 70% (by total volume) of mineral filler, providing a good anti-icing and snow melting capacity while the mixtures were still performed very well.

Determining ephemeral gully erosion process with the volume replacement method

BackgroundEphemeral gully erosion is an important form of hillslope erosion all over the world. It is of high significance to understand its erosion mechanism. ObjectiveA new volume replacement method is proposed to determine ephemeral gully erosion process. Styrofoam particles of hard granules were used to refill the eroded ephemeral gully sections lined with gauze sheet to the original elevation, before their volumes were measured for estimating sediment concentration distribution along the ephemeral gully. The measurement and the computational methodologies are illustrated in details. MethodA series of flume experiments were conducted with a silt loam (loess) soil to study ephemeral gully erosion process under four slope gradients and three flow rates. The ephemeral gully was pre-formed before each experimental run. The volumes of the eroded ephemeral gully sections were measured and the distribution of sediment concentration along the gully was computed at 1m intervals. For comparison purpose, the sediment concentration distribution along the eroded gully was also measured by manual sampling of the sediment-laden water flow with cups. ResultsThe results showed that both the sediment processes estimated by the volume replacement and measured by the sampling method were very similar. The estimated and measured sediment concentrations increased with ephemeral gully length under a given flow rate. The increase rate decreased gradually as the sediment concentration gradually approached its limit. ConclusionsUnder different flow rates and slope gradients, the sediment concentrations at different distances, as estimated by the volume replacement method were about the same as those measured with the sampling method. The new method provides a useful and efficient way in determining the ephemeral gully erosion, and helps to understand ephemeral gully erosion process.

Estimating rill erosion process from eroded morphology in flume experiments by volume replacement method

Rills are commonly found on the sloped farm fields in the loess regions worldwide, especially on Chinese Loess Plateau. The erosion process along a rill provides information for understanding the rill erosion mechanism. This study uses a volume replacement method to estimate the rill erosion processes by refilling the eroded rill segments. The sediment concentration was calculated by summering the eroded soil mass and divided by the total water volume during the erosion period. A flume that was 0.6 wide and 12m long was subdivided into strips of 0.1m wide and 12m long to imitate eroding rills. A typical silty-loam soil from the Loess Plateau of China was used for the experiments. The commutative eroded rill volumes along the rills under five slopes and three flow rates were measured at 11 rill segments. All the sediment-laden runoff was harvested at the rill outlet to measure the average sediment concentration. The sediment concentrations at locations higher than that at the outlet were caused by sediment deposition and removed from the data set. The computed sediment concentration processes increased with slope gradient and flow rate. They also increase with rill length exponentially, with all the coefficients of determination above 0.95. The results were about the same of the previous studies, with sampling method. This demonstrates that the proposed method is a feasible approach to estimate rill erosion distribution. The data set is applicable to the estimation of rill erosion model parameters. This study will provide a basis for estimating rill erosion model parameters.

Influence of the chloride-based anti-freeze filler on the properties of asphalt mixtures

This paper focused on the properties of asphalt mixtures containing anti-freeze filler (ICB-1, ICB-2, ICB-3 and ICB-4) with the volume replacement method. And the void content, high- and low-temperature properties and the susceptibility to moisture damage are investigated by experimental method. Based on the colligative property of dilute solution, a new evaluating model is developed, and proved with observation test. The result shows that the asphalt mixture containing a smaller particle obtains a better high- or low-temperature property, and water stability. Furthermore, it is believed that a better anti-freeze property of asphalt mixtures will be obtained in a little precipitation and high temperature conditions. Besides, in heavy event, a liquid layer appears between pavement and snow/ice, which would facilitate the mechanical removal of the snow or ice.

Volume replacement method for direct measurement of soil moisture and bulk density

Volume replacement method for direct measurement of soil moisture and bulk density

Oncoplastic Surgical Techniques for Personalized Breast Conserving Surgery in Breast Cancer Patient with Small to Moderate Sized Breast

Oncoplastic surgery has revolutionized the field of breast conserving surgery (BCS). The final aims of this technique are to obtain an adequate resection margin that will reduce the rate of local recurrence while simultaneously improving cosmetic outcomes. To obtain successful results after oncoplastic surgery, it is imperative that patients be risk-stratified based on risk factors associated with positive margins, that relevant imaging studies be reviewed, and that the confirmation of negative margins be confirmed during the initial operation. Patients who had small- to moderate-sized breasts are the most likely to be dissatisfied with the cosmetic outcome of surgery, even if the defect is small; therefore, oncoplastic surgery in this population is warranted. Reconstruction of the remaining breast tissue is divided into volume displacement and volume replacement techniques. The use of the various oncoplastic surgeries is based on tumor location and excised breast volume. If the excised volume is less than 100 g, the tumor location is used to determine which technique should be used, with the most commonly used technique being volume displacement. However, if the excised volume is greater than 100 g, the volume replacement method is generally used, and in cases where more than 150 g is excised, the latissimus dorsi myocutaneous flap may be used to obtain a pleasing cosmetic result. The local recurrence rate after oncoplastic surgery was lower than that of conventional BCS, as oncoplastic surgery reduced the rate of positive resection margins by resecting a wider section of glandular tissue. If the surgeon understands the advantages and disadvantages of oncoplastic surgery, and the multidisciplinary breast team is able to successfully collaborate, then the success rate of BCS with partial breast reconstruction can be increased while also yielding a cosmetically appealing outcome.

BULK DENSITIES OF COOKIES UNDERGOING COMMERCIAL BAKING PROCESSES

ABSTRACTThe densities of food products undergoing baking processes in commercial multi‐zone band ovens of a local plant were measured with a volume replacement method along with a photographic procedure. Three kinds of cookies were selected as the sample products. It was found that the densities are closely related to the temperature and moisture content of cookies during the baking processes. This relationship is statistically represented by polynomial regression equations. The correlation coefficients were better than 0.970. According to the examination of changes in volume of cookies undergoing baking processes, expansion ratios were found to be 2.0‐2.5.