Proportion Of Aggregates Research Articles

High-performance localized high-concentration electrolytes by diluent design for long-cycling lithium metal batteries

Electrolyte design is essential for stabilizing lithium metal anodes and localized high-concentration electrolyte (LHCE) is a promising one. However, the state-of-the-art LHCE remains insufficient to ensure long-cycling lithium metal anodes. Herein, regulating the solvation structure of lithium ions in LHCE by weakening the solvating power of diluents is proposed for improving LHCE performance. A diluent, 1,1,2,2,3,3,4,4-octafluoro-5-(1,1,2,2-tetrafluoroethoxy) pentane (OFE), with weaker solvating power is introduced to increase the proportion of aggregates (an anion interacts with more than two lithium ions, AGG-n) in electrolyte compared with the commonly used 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TTE). The decomposition of AGG-n in OFE-based LHCE intensifies the formation of anion-derived solid electrolyte interphase and improves the uniformity of lithium deposition. Lithium metal batteries with OFE-based LHCE deliver a superior lifespan of 190 cycles compared with 90 cycles of TTE-based LHCE under demanding conditions. Furthermore, a pouch cell with OFE-based LHCE delivers a specific energy of 417 Wh/kg and undergoes 49 cycles. This work provides guidance for designing high-performance electrolytes for lithium metal batteries.

Reoperation following transcatheter aortic valve replacement: Insights from 10 years' experience

ObjectiveUse of transcatheter aortic valve replacement (TAVR) has demonstrated dramatic growth in the past decade. This study aims to investigate implications of post-TAVR reoperation from our 10-year experience. MethodsBetween 2011 and 2022, 66 post-TAVR patients underwent a reoperation, consisting of 42 (63.6%) patients with native TAVR and 24 (36.4%) patients with valve-in-valve TAVR (VIV-TAVR) after surgical aortic valve replacement. ResultsThe aggregate proportion of patients belonging to the low-/intermediate-risk group at the time of TAVR exceeded that of the high-/extreme-risk cohort in 2021. The native TAVR group received a larger TAVR valve, whereas more frequent low-risk status at the time of TAVR than the VIV-TAVR group. Concurrent procedures were highly common during reoperation and isolated surgical aortic valve replacement represented only 18.2% of the entire cohort. The native TAVR group demonstrated significantly higher TAVR explant difficulty index score (2.0 vs 1.0 points; P < .001) and operative mortality (14.2% vs 0%; P = .079) compared with the VIV-TAVR group. The 8-year cumulative incidence of reoperation was 1.9% and 14.1% (subdistribution hazard ratio, 8.0; 95% CI, 4.1-15.9; P < .001) in the native and VIV-TAVR group, respectively. Furthermore, cumulative incidence of valve reintervention, combining reoperations and redo TAVRs, was 3.3% and 19.0% (subdistribution hazard ratio, 6.2; 95% CI, 3.6-10.9; P < .001). ConclusionsLow-/intermediate-risk patients are emerging as the predominant group necessitating reoperations. Native TAVR was associated with lower postimplant reintervention rates, albeit with higher reoperative technical difficulty and mortality. Conversely, VIV-TAVR was associated with higher reintervention, but demonstrated lower technical difficulty and mortality for reoperation.

Study on the Utilization of Waste Thermoset Glass Fiber-Reinforced Polymer in Normal Strength Concrete and Controlled Low Strength Material.

Thermoset glass fiber-reinforced polymers (GFRP) have been widely used in manufacturing and construction for nearly half a century, but the large amount of waste produced by this material is difficult to dispose of. In an effort to address this issue, this research investigates the reuse of thermoset GFRP waste in normal strength concrete (NSC) and controlled low-strength materials (CLSM). The mechanical performance and workability of the resulting concrete were also evaluated. To prepare the concrete specimens, the thermoset GFRP waste was first pulverized into granular pieces, which were then mixed with cement, fly ash, and water to form cylindrical concrete specimens. The results showed that when the proportion of thermoset GFRP waste aggregate in the concrete increased, the compressive strengths of NSC and CLSM would decrease. However, when incorporating 5% GFRP waste into CLSM, the compressive strength was 7% higher than concrete without GFRP. However, the workability of CLSM could be improved to meet engineering standards by adding an appropriate amount of superplasticizer. This finding suggests that the use of various combinations of proportions in the mixture during production could allow for the production of CLSM with different compressive strength needs. In addition, the use of recycled thermoset GFRP waste as a new aggregate replacement for traditional aggregates in CLSM was found to be a more sustainable alternative to the current CLSM combinations used in the market.

Study on the Performance of Bitumen Waste Stone Column in Soil Stabilization

Stone Column is a technique for improving and stabilising weak soils such as soft clays, silts, and loose sands, allowing highway facilities, storage tanks, embankments, and bridge abutments to be built. We are utilising bituminous waste as an alternative material for coarse aggregate in the construction of stone columns to save expenditure by partially replacing coarse aggregate with bituminous waste. We're mixing bitumen waste and coarse aggregate, which have been passed through a 16 mm IS sieve and are being retained . Different mix proportions of coarse aggregate and bitumen waste for stone column samples represented as (X% aggregate + Y% bitumen waste) were tested such as (100%C), (70%C+30%B), (60%C+40%B), (50%C+50%B) and (100%B). Intermediate Plastic Clayey soil (CI) at OMC was used as the test sample in which stone column was installed. The CBR test was performed on the stone column with a diameter of 50 mm and depth of 100 mm installed in the compacted soil in CBR mould to determine CBR value and bearing capacity of samples. After that the results were compared with 100% coarse aggregate stone column sample (100%C).

Carbon stock, aggregate stability and hydraulic properties of soils under tillage, crop rotation and mineral fertiliser application in sub-humid Zimbabwe

Appropriate tillage and crop diversifications can improve soil quality leading to yield sustainability. Our objective was to quantify tillage, crop rotation and mineral fertiliser application effects on carbon sequestration, aggregation and soil water movement after two cropping cycles in the smallholder sector of Zimbabwe. Two split-plot experiments were set up at four sites on sandy, loamy and clayey soils. At experiment 1, crop rotation (maize-soya bean; continuous maize) was the main plot and mineral fertiliser ((NPKS (180 N + 30P2O5+30K2O+6.5SO3 kg ha−1); control (no fertiliser added)) was the sub-plot. At experiment 2, tillage (reduced, conventional) was the main plot and mineral fertiliser (NPKS; control) was the sub-plot. Soil samples collected from 0 to 0.2 m and 0.2–0.4 m layers were analysed for soil organic matter (SOM) content, bulk density and proportion of water stable aggregates. Saturated hydraulic conductivities (Ks), steady state infiltration rates (is) and soil sorptivities (Sp) were estimated from fitting field infiltration data into the Phillip model. SOM stocks (mean = 3.483 Mg ha−1) were significantly increased by reduced tillage at the sandy site and higher (p < 0.05) in 0–0.20 m than in 0.20–0.40 m layers at clayey sites. Proportion of water stable aggregates increased (p < 0.05) under reduced tillage compared with conventional tillage and under rotation compared with continuous maize system. Bulk densities were 11% lower (p < 0.05) in the 0–0.20 m than in 0.20–0.40 m layers. The estimated Ks(1 × 10−4-8x10−4 cm s−1) and is (7.08–55 × 10−4 cm s−1) were at least 100% higher (p < 0.05) under rotation compared with continuous maize whilst sorptivities (0.050–0.143 cm s−05) did not vary across the treatments. NPKS fertiliser reduced (p < 0.05) is by up to 1.8 fold compared with the control. Short term adoption of reduced tillage and maize-soya bean rotation can mitigate soil structural degradation; increase water recharging and increase carbon sequestration quicker in sands than in the buffering clays making the practices more relevant in the smallholder sector.

3D-printed concrete permanent formwork: Effect of postcast concrete proportion on interface bonding

Using 3D concrete printing technology to produce permanent formwork for building components is a promising method that maximizes design freedom and material savings. In this study, 3D-printed permanent formwork made of concrete with coarse aggregate is manufactured and post cast with concrete containing different coarse aggregate particle size ratios. The results indicate that the splitting tensile strength of the concrete interface reaches 2.3 ∼ 4.4 MPa, of which the reduction rate range from 12.8%∼35.7% with higher bonding positions. Mesoscopic observation reveals the voids concentration and a lack of coarse aggregate phenomenon in the interface area. Increasing the proportion of small-sized coarse aggregates in the pouring concrete can better fill and improve the splitting strength of the interface area.

Laboratory evaluation of microwave heating and skid resistance of pavement friction surfacing using calcined bauxite and magnetite aggregates

A high friction surface treatment (HFST) with magnetite (MT) aggregates instead of conventional calcined bauxite (CB) aggregates as microwave absorbers were prepared in this paper. The deicing properties by microwave heating and long-term skid resistance of HFST with different proportions of CB and MT aggregate were evaluated. The deicing properties by microwave heating of HFST were determined by electromagnetic characteristics, heating surface temperature, and microwave deicing time (MDT) tests. The long-term skid resistance of the HFST was characterized by conducting dynamic friction coefficient and mean profile depth (MPD) tests after long-term polishing using a three-wheel polishing device. The results showed that the electromagnetic characteristics of HFST were enhanced greatly by the addition of MT. The microwave heating efficiency of HFST was enhanced by the increase of MT substitution rate, which further enhanced its microwave deicing efficiency. The microwave deicing efficiency of HFST with MT substitution rate of 25% was 1.4 times that of HFST with MT substitution rate of 0%. Long-term skid resistance of HFST was reduced by the addition of MT, however, HFST with MT substitution rate of 25% also maintained a terminal μ40 and μ60 above 0.7, which can provide higher friction comparable with other high friction aggregate such as taconite, basalt, emery and flint. To improve the deicing properties by microwave heating and maintain high skid resistance, 25% MT replacement rate in HFST is recommended.

Evolution of Gold and Iron Oxide Nanoparticles in Conjugates with Methotrexate: Synthesis and Anticancer Effects.

Au and Fe nanoparticles and their conjugates with the drug methotrexate were obtained by an environmentally safe method of metal-vapor synthesis (MVS). The materials were characterized by transmission and scanning electron microscopy (TEM, SEM), X-ray photoelectron spectroscopy (XPS), and small-angle X-ray scattering using synchrotron radiation (SAXS). The use of acetone as an organic reagent in the MVS makes it possible to obtain Au and Fe particles with an average size of 8.3 and 1.8 nm, respectively, which was established by TEM. It was found that Au, both in the NPs and the composite with methotrexate, was in the Au0, Au+ and Au3+ states. The Au 4f spectra for Au-containing systems are very close. The effect of methotrexate was manifested in a slight decrease in the proportion of the Au0 state-from 0.81 to 0.76. In the Fe NPs, the main state is the Fe3+ state, and the Fe2+ state is also present in a small amount. The analysis of samples by SAXS registered highly heterogeneous populations of metal nanoparticles coexisting with a wide proportion of large aggregates, the number of which increased significantly in the presence of methotrexate. For Au conjugates with methotrexate, a very wide asymmetric fraction with sizes up to 60 nm and a maximum of ~4 nm has been registered. In the case of Fe, the main fraction consists of particles with a radius of 4.6 nm. The main fraction consists of aggregates up to 10 nm. The size of the aggregates varies in the range of 20-50 nm. In the presence of methotrexate, the number of aggregates increases. The cytotoxicity and anticancer activity of the obtained nanomaterials were determined by MTT and NR assays. Fe conjugates with methotrexate showed the highest toxicity against the lung adenocarcinoma cell line and Au nanoparticles loaded with methotrexate affected the human colon adenocarcinoma cell line. Both conjugates displayed lysosome-specific toxicity against the A549 cancer cell line after 120 h of culture. The obtained materials may be promising for the creation of improved agents for cancer treatment.

Management practices and incidence of pests in plantain (Musa paradisiaca AAB) crops. Consequences on the sustainability of the cropping systems

Plantain (Musa paradisiaca AAB) is one of the most important staple crops in the tropics, particularly in the Caribbean. Pests are the main constraint to plantain production and yield increases may be possible by improving pest management. However, there is a lack of data on these cropping systems and a need to identify new elements of improved production systems that can control pests in line with the principles of agroecological transition. In this study, we test the hypothesis that crops grown in good quality soils are less susceptible to pests. To this end, an agroecological diagnosis of the biological, physical, morphological and chemical soil conditions and the occurrence of pests, in particular plant-parasitic nematodes, was carried out on 21 plantain plots with contrasting management in Guadeloupe (French West Indies). After classifying these plots according to their management practices, from conventional to agroecological, we searched for relationships between cropping systems, soil quality and pests using a series of synthetic quality indices. Four different cropping systems were identified and compared: conventional intensive, intermediate, low-input and agroecological, according to the type and amount of agrochemicals used. Our data showed that the Chemical Index was significantly improved in the agroecological systems due to increases in pH, CEC, base saturation and total C and N content. The Morphological Index increased regularly from intensive to agroecological systems and was significantly higher in agroecological systems with higher proportions of biogenic aggregates. Soil macroinvertebrate communities were significantly influenced by production systems, with the highest values of the Macrofauna Index in low input and agroecological production systems. We also showed that plant parasitic nematodes were better regulated in agroecological production systems. Furthermore, the agroecological system achieved similar levels of crop production to conventional systems, without the use of pesticides. In addition, these agroecological cropping systems extend the duration of plantain plots, which is an indicator of the good health of these systems.

Vibration quality evaluation of reinforced concrete using energy transfer model

Vibration is an important step to ensure the compactness of reinforced concrete. In this study, the energy transfer model is firstly proposed based on the working mechanism of the internal vibrator and vibration energy theory to evaluate the vibration quality, and the reliability of the model is verified by the experiment of sinking ball. In addition, the optimal combinations of process parameters are obtained. The worse the fluidity of concrete and the larger the aggregate proportion, the faster the energy attenuation in concrete, but the total energy absorbed by concrete and the energy transfer efficiency of the vibrator increase. The overall efficiency is greater than 57% and the highest average efficiency is 66.1%. The rebar not only accelerates the energy attenuation rate but also reduces the effective energy in the concrete. In the experiments, the average energy consumption rates of rebar are 28.5%, 57.3% and 70.9% with the reinforcement spacing of 20, 10 and 5 cm respectively. The proposed model provides a new method to evaluate the vibration quality, which contributes to dealing with unqualified areas in time and providing reliable process parameters for vibrating construction.

3D numerical investigation of functionally graded concrete

In the design of engineering structures, concrete is assumed to have homogeneously mechanical properties. However, in reality, the concrete material is usually not uniform with respect to the height of structures because segregation mostly occurs during construction. The higher density is presented at, the lower part of the structure due to a higher proportion of aggregate and vice versa. Moreover, the disparity of creep, shrinkage, hydration heat, and curing method also leads to the difference in the quality of concrete. Therefore, it is necessary to study the responses of a concrete element with various mechanical properties. In this study, the functional elastic modulus of concrete material (FGC) is investigated numerically for its effects on the static responses of the element under axial compression. Conventional Finite Element Method (FEM) and Meshless method are used to model the structure. The reliability of the numerical model is validated by comparing the obtained results with experimental data.

Mixed Plantations Induce More Soil Macroaggregate Formation and Facilitate Soil Nitrogen Accumulation

Nitrogen plays a crucial role in limiting plant growth and determining net primary productivity in forest ecosystems. However, variations and influencing factors of soil nitrogen distribution on the aggregate scale in pure and mixed Chinese fir (Cunninghamia lanceolata (Lamb.) Hook) plantations remain unclear. This study aimed to explore how soil aggregate composition, geometric mean diameter (GMD), mean weight diameter (MWD), total nitrogen (TN), total acidolyzable nitrogen (TAN), available nitrogen (AN), nonacidolyzable nitrogen (AIN), amino acid nitrogen (AAN), nitrate nitrogen (NO3−-N), cidolyzable ammonia nitrogen (AMN), unknown-acidolyzable nitrogen (HUN), amino sugar nitrogen (ASN), and ammonium nitrogen (NH4+-N) contents and stocks varied with aggregate size (&gt;2, 1–2, 0.25–1, and &lt;0.25 mm) and stand type [Chinese fir mixed with Michelia macclurei Dandy (CF + MM), Chinese fir mixed with Mytilaria laosensis Lecomte (CF + ML) and pure stands of Chinese fir (CF)] in 0–20 and 20–40 cm soil depth. Soil N content in different stand types of Chinese fir plantations decreased as the aggregate size increased, whereas the soil N stock exhibited the opposite trend. In contrast to CF soil, CF + MM and CF + ML soil displayed a significant increase in MWD, GMD, and aggregate-associated TN, AN, NO3−-N, NH4+-N, AIN, AAN, ASN, and AMN contents and stocks, especially CF + MM soil. Organic N was more sensitive to the response of aggregate size and stand type than mineral N. Redundancy analysis and Pearson’s correlation analysis indicated that the 0.25–1 mm aggregate proportion was the main controlling factor for the variations in soil N content and storage. Overall, this study contributed significantly to the promotion of the sustainable use of soil resources and reference information for the scientific management and sustainable development of Chinese fir forests.

Effects of cyanobacteria- and moss-biocrusts on soil aggregate stability and splash erosion in croplands of the China Mollisols area.

To investigate the effects of biocrusts development on aggregate stability and splash erosion of Mollisols and to understand its function in soil and water conservation, we collected biocrusts (cyano crust and moss crust) samples in croplands during the growing season and measured the differences in aggregate stability between biocrusts and uncrusted soil. The effects of biocrusts on reduction of raindrop kinetic energy were determined and splash erosion amounts were obtained with single raindrop and simulated rainfall experiments. The correlations among soil aggregate stability, splash erosion characteristics, and fundamental properties of biocrusts were analyzed. The results showed that compared to uncrusted soil, the cyano crust and the moss crust decreased the proportion of soil water-stable aggregates <0.25 mm by 10.5% and 21.8%, respectively, while their soil water-stable aggregates 5-10 mm were 4.0 and 8.8 times as that of uncrusted soil. In contrast to uncrusted soil, the macroaggregate content (R0.25), mean weight diameter (MWD), and geometric mean diameter (GMD) of biocrusts were 31.5%, 76.2%, and 33.5% higher, respectively. In addition, biocrusts reduced raindrop kinetic energy by an average of 0.48 J compared to uncrusted soil. The breakthrough raindrop kinetic energy of cyano crust and moss crust were 2.9 and 26.2 times as that of uncrusted soil, while the reduction of raindrop kinetic energy by cyano crust with high biomass was 1.3 and 6.6 times as that of medium and low biomass, respectively. Under the single raindrop and simulated rainfall conditions, biocrusts reduced splash erosion amounts by 47.5% and 79.4%, respectively. The proportion of aggregates >0.25 mm in the splash soil particles of biocrusts (37.9%) was 40.3% lower than that of uncrusted soil, while the proportion of aggregates >0.25 mm decreased as biocrust biomass increased. Moreover, the aggregate stability, splash erosion amount, and fundamental properties of biocrusts were significantly correlated. The MWD of aggregates was significantly and negatively correlated with the splash erosion amount under single raindrop and simulated rainfall conditions, indicating that the improved aggregate stability of surface soil caused by biocrusts accounted for reducing splash erosion. The biomass, thickness, water content, and organic matter content of biocrusts had significant effects on aggregate stability and splash characteristics. In conclusion, biocrusts significantly promoted soil aggregate stability and reduced splash erosion, which had great significance to soil erosion prevention and the conservation and sustainable utilization of Mollisols.

Determination of Marshall parameters of bituminous mix by using non-destructive testing method

Non-destructive test (NDT) is a fast, easy, cost-effective in-situ method of inspecting, testing, evaluating the different materials, component assemblies, etc. Ultrasonic Pulse Velocity (UPV) test is one of the best NDT methods frequently used for cement concrete for evaluating various parameters e.g., strength, life, crack depth, corrosion, etc. Conventional destructive test (e.g., Marshall Test) is performed to determine the optimum bitumen content (OBC) and various Marshall parameters of bituminous concrete. Destructive tests are laborious, time-consuming, costly, moreover; it is impossible to find the in-situ characteristics of pavement by destructive test. In recent times, the UPV test has been emerging for bituminous concrete work. However, much reliability of non-destructive test on bituminous mix has not been developed. In this study, the Proceq UPV apparatus has been used to determine the dynamic modulus by a non-destructive test. To implement such study different proportions of virgin aggregate and of RAP material such as 0:100, 10:90, 20:80, 30:70, 40:60 and 50:50 % was utilized to fabricate the bituminous concrete (BC). Correlations between dynamic modulus and stability, flow value, density, OBC (Optimum bitumen content) have been developed. These correlations can predict Marshall strength and parameters of conventional and non-conventional bituminous mix using the UPV apparatus. The results suggested that the 40:60% RAP-modified BC mix has executed superior results than the other mixes.

Structural Performance of Cement-treated Base Layer by Incorporating Reclaimed Asphalt Material and Plastic Waste

The reuse of reclaimed asphalt material (RAM) and polyethylene terephthalate (PET) plastic waste is a reliable approach to limit the use of virgin aggregates for road construction and mitigate environmental challenges. This study highlights the structural performance of the cementitious base or cement-treated base (CTB) layer by incorporating reclaimed asphalt and plastic waste material. Structural compatibility of CTB layer with different proportions of RAM (20%, 45%, 70% and 95%), virgin aggregates and plastic waste (5%) is recognized by the moisture-density relationship, unconfined compressive, indirect tensile strength, flexural strength and California bearing ratio tests. In the current study, a ranking methodology is used to analyze the overall suitability of the cementitious base mix proportions using different laboratory test parameters. Furthermore, a finite element analysis using the ANSYS software is performed to investigate the effect of CTB layer on the pavement structural responses. Also, using the central public works department guidelines, a cost comparative study is provided. Experimental results showed that all the cementitious base mixes met the requirements for the unconfined compressive strength, except for the 95% and 70% RAM mixes. Therefore, 20%-45% of RAM can partially be used in the CTB layer to replace virgin aggregates partially. The finite element analysis results showed that CTB reduced fatigue strain by 57% and surface deformation by 47%. Moreover, it has been concluded that by utilizing a cementitious base with RAM, there is a 30% cost reduction. KEYWORDS: Reclaimed asphalt material, Cement-treated base, Polyethylene terephthalate, Finite element analysis, Unconfined compressive strength.

The Usage of Organic Waste in Porous Asphalt

Porous asphalt is a mixture of asphalt with a low proportion of fine aggregate to obtain high air void content, which would create a water drainage path inside the pavement to be channelled into the drainage system. Usually, the materials used as filler are relatively expensive, such as Portland cement and lime, and hence, it is necessary to look for other cheaper alternative materials, such as organic waste. This study aims to determine the effect of using organic waste as a filler in porous asphalt mixtures on the Marshall and Permeability tests results. The organic wastes chosen were used coffee grounds (7%, 8%, 9%), tofu dregs (7%, 8%, 9%), sawdust (7%, 8%, 9%), and coconut fibre (4%, 5%, 6%). The porous asphalt in this study was prepared based on the Australian Asphalt Pavement Association (AAPA) standard. The results showed that the best outcome came from using 7% of sawdust on the porous asphalt mixture.

Manufacture of Load Bearing Concrete Masonry Units Using Waste Demolishing Material

The presence of construction wastes such as clay bricks, glass, wood, plastic, and others in large quantities causes serious environmental problems in the world. Where these wastes can be used to preserve the natural resources used in construction and reduce the impact of this problem on the environment, it also works to reduce the problem of high loads of concrete blocks. Clay bricks aggregate (AB) can be recycled as coarse aggregate and replaced with volumetric proportions of coarse aggregate by ( 5% and 10%), as well as the use of clay brick powder (PB) by replacing its weight of cement (5% and 10%) and reduced in the manufacture of concrete blocks (blocks). Four mixtures will be prepared and tested to learn how to reuse the brick coarse aggregate ACB and PB powder brick as substitute materials for producing concrete blocks, use the water spray method to treat concrete building blocks (blocks) and check the Dimensions and compressive strength, and absorption.

An assessment of various pools of organic phosphorus distributed in soil aggregates as affected by long‐term P fertilization regimes

AbstractThe phosphorus (P) forms in long‐term fertilization determine the fate and transport of P in soil. However, the fate of various pools of organic P of added P in the long‐term measured with sequential chemical fractionation is not well‐understood. Four soil physical aggregates (&gt;250, 125–250, 63–125 and &lt;63 μm) from 0‐ to 20‐cm depth after 35 years of long‐term fertilization treatments including control (CK), nitrogen and phosphorus fertilizer (NP) and NP combined with farmyard manure (NPM) under continuous winter wheat were separated using settling tube apparatus. Results showed that the application of long‐term P fertilization had no apparent effects on promoting the mass proportion of soil aggregates except for &gt;250 μm, where the NP and NPM treatments significantly increased the mass proportion by 60% and 70% over CK, respectively. Compared with CK, P fertilizer (NP and NPM) treatments significantly increased organic P (Po) contents in each size aggregate. In particular, mean labile Po increased by 35% and 246%, moderately labile Po by 125% and 161%, nonlabile Po by 105% and 170% and total Po (TPo) by 101% and 178%, respectively, under NP and NPM treatments, respectively. There was a significant correlation between soil organic carbon (SOC) and Po fractions. SOC was exponentially positively correlated with labile Po but linearly positively correlated with moderately labile Po, nonlabile Po and TPo fractions among soil aggregates. A reduced C:Po ratio (&lt;100) in soil aggregates among treatment indicates a large amount of available P accumulated in soils, and soil P loss risk in the study site is still high. Our results show that the Po pool measured by sequential chemical fractionation may represent an important, yet often overlooked, source of P in agriculture ecosystems. According to the result, long‐term mineral P fertilizer combined with organic amendments better sustains soil structural stability in large aggregates, contributing more Po availability in the moderately labile P followed by labile P in soil aggregates.

Effect of Aggregate on the Performance of Fly-Ash-Based Geopolymer Concrete

The influence of geopolymer binder characteristics on the performance of geopolymer concrete has been extensively investigated. Yet, the influence of aggregate properties has not been thoroughly studied, and it is usually assumed that their effect is the same as in cement concrete. This study investigates the effect of aggregate on the performance of fly-ash-based geopolymer concrete. A systematic experimental study was undertaken to investigate the effect of aggregate parameters, including volume fractions (AVFs), coarse aggregate to the total aggregate ratio (CAR), maximum coarse aggregate size (MAS), and fineness modulus of fine aggregate (FFM) on the compressive strength, slump, apparent volume of permeable pores (AVPPs), and the air content of geopolymer concrete. Response surface methodology (RSM) using the central composite design approach was utilized to design the experiments and analyze the results statistically. The analysis shows that all of the investigated aggregate parameters have significant first-order effects on the measured properties. No significant interaction between any of the investigated parameters was found. The aggregate may alter the geopolymerization processes, whereby SEM-EDS analysis revealed statistically significant variations in the elemental concentrations of the produced paste as the aggregate parameters changed. Quantitative weights were assigned to the effect of the investigated aggregate parameters on the measured properties. Multi-objective optimization was carried out to obtain the best combinations of the investigated parameters. Additionally, the developed contour graphs may provide an effective tool that can be used as a guide in establishing the first trial mixtures. A wide range of consistencies (10–210 mm slump) and compressive strengths (15–55 MPa) can be obtained by controlling the aggregate grading and proportions.

Hepatitis B immune status of staff in smaller acute healthcare facilities.

Objective To determine the proportion of staff employed in smaller Victorian public acute healthcare facilities with evidence of immunity to hepatitis B. Methods For optimal long-term immunity, a completed hepatitis B vaccination course and post vaccination hepatitis B surface antibody (anti-HBs) level ≥10 mIU/mL is desirable for all high-risk staff employed in healthcare facilities. For the financial years 2016/17-2019/20, a standardised surveillance module developed by the Victorian Healthcare Associated Infection Surveillance System (VICNISS) Coordinating Centre was completed by the smaller Victorian public acute healthcare facilities (individual hospitals with Results A total of 88 healthcare facilities reported hepatitis B immunity status of high-risk (Category A) staff (n = 29 920) at least once over 5 years; 55 healthcare facilities reported more than once. The aggregate proportion with evidence of optimal immunity was 66.3%. Healthcare facilities with 100-199 Category A staff employed reported the lowest evidence of optimal immunity (59.6%). Of all Category A staff with no evidence of optimal immunity, the majority had 'unknown' status (19.8%), with only 0.6% overall who declined vaccination. Conclusions Our study found evidence of optimal staff hepatitis B immunity in only two-thirds of Category A staff working in surveyed healthcare facilities.