Compressibility Coefficient Research Articles

A Nonuniform Compressed High-Order Mode Dipole With Sidelobe Suppression

A nonuniform compressed high-order mode dipole with suppressed sidelobe is proposed and investigated. The main performance characteristics, such as directivity, sidelobe, and radiation resistance of a third-order mode dipole with two independent compression coefficients are fully investigated. The investigation shows that enhanced directivity, suppressed sidelobe, and high radiation resistance are achieved simultaneously by selecting the appropriate compression coefficients. The compressed converse current leads to the sidelobe suppression. To verify the investigation, a third-order mode dipole antenna with nonuniform compression is designed, fabricated, and measured. The measurement shows that the reflection coefficient is less than −10 dB over the band of 2.46–2.65 GHz (one of the sub-6 GHz bands of fifth generation). The achieved gain is 4.7 dBi. The sidelobe level is less than −15.4 dB, 9.4 dB lower than the uniform compressed third-order mode dipoles.

A Hybrid Modulation Strategy With Neutral Point Voltage Balance Capability for Electrolytic Capacitorless Vienna Rectifiers

Electrolytic capacitorless Vienna rectifiers have many advantages, such as longer lifetime and higher power density. However, the reduced dc-link capacitance aggravates the voltage stress due to the neutral point (NP) fluctuation. In this article, a hybrid modulation strategy combining the modulations of redundant vector and compression vector is proposed, which can realize the NP voltage balance for electrolytic capacitorless Vienna rectifiers. On the basis of analyzing the limitation of NP-balance capability of conventional space vector pulsewidth modulation (PWM) strategy in the region of high modulation index, the negative influence of reduced capacitance on the NP fluctuation and the input current harmonics is revealed. To suppress the NP fluctuation, the compression coefficient is introduced to redistribute the duty cycles of voltage vector, which can reduce the negative effect of medium vector on the NP voltage. In addition, the phase voltage error is modeled to reduce the input current harmonics with the appropriate adjustment factor. The implementation of the proposed strategy is realized by the equivalent carrier-based PWM, which can avoid the sector judgment and angle calculation. By using the proposed strategy, the NP voltage balance and the input current harmonics reduction can be realized simultaneously. The effectiveness of the proposed strategy is verified on an electrolytic capacitorless Vienna rectifier platform.

Densities and isothermal compressibilities from perturbed hard-dimer-chain equation of state: application to nanofluids

Abstract Densities and isothermal compressibilities of several nanofluids were modelled using a perturbed hard-chain equation of state (EoS) by an attractive term from Yukawa tail in 273–363 K range and pressure up to 45 MPa. The nanofluids of interest comprise TiO2-Anatase (-A), TiO2-Rutile (-R), SnO2, Co3O4, CuO, ZnO, and Al2O3 as nanoparticles dispersed in ethylene glycol, water, poly ethylene glycol, ethylene glycol + water, and poly ethylene glycol + water as base fluids. The EoS was capable of estimating 1397 density data of 9 nanofluids with the overall average absolute deviations (AAD) of 0.90%. The coefficients of isothermal compressibility of 6 selected nanofluids were also predicted using the EoS with the AAD of 5.74% for 1095 data points examined. The PHDC EoS was not capable of estimating the excess volumes of 3 selected EG-, PEG-, and water-based nanofluids accurately as the relative deviations from the literature data were greater than 34%, even though the trend of results against the nanoparticle concentration was in accord with the literature. To further investigate the density prediction, we have trained a neural network with a single hidden layer and 17 neurons which was able to predict the densities of nanofluids accurately.

Mechanical and Electronic Properties of a Carbon-Composite 3D Nanomaterial with an Island-Type Topology

An atomistic model of a carbon-composite 3D nanomaterial with an island-type topology based on fullerene and graphene fragments as well as chiral/achiral single-walled carbon nanotubes (SWCNTs) with a subnanometer diameter is constructed. The island type refers to the presence of inhomogeneously distributed local regions with increased density of the nanomaterial in the structure of the composite. The effect of the concentration of nanotubes in the composite on the volume compressibility and electronic properties is investigated. It is found that an increase in the mass fraction of SWCNTs in the composite leads to a decrease in the coefficient of volume compressibility and, at the same time, improvement in the conductive properties. Classical molecular dynamics and the density functional based tight binding (DFTB) method with the use of dispersive energy correction are used for the physically correct description of individual fragments of the composite which are not covalently bound.

Durability of reactive powder concrete of drilling shaft and triaxial compression damage constitutive model under composite salt erosion

This study aimed to improve the bearing capacity of the drilling shaft and the durability of resistance to composite salt erosion in water-rich and weakly consolidated formations. Hence, reactive powder concrete (RPC) is proposed as the construction material for the drilling shaft. RPC macroscopic mechanical behavior, mesoscopic pore structure, and microscopic characteristics as well as a triaxial compression damage constitutive model under a composite salt erosion environment were studied and analyzed. First, the accelerated corrosion test method was used to compare the macroscopic mechanical properties and apparent morphology deterioration of C70 high-strength and high-performance concrete with those of RPC140 and RPC 110 (based on the same mix ratio) prepared by autoclave curing and standard curing, respectively, under composite salt solutions of three concentrations. Then, mercury intrusion porosimetry and scanning electron microscopy analyses were used to determine the pore structure changes and micro hydration characteristics of the concrete specimens before and after salt erosion. The results showed that the high concentration of the composite salt aggravated the deterioration of the concrete performance, and the mass loss rate and compressive strength corrosion resistance coefficient of the concrete changed dynamically as the age of erosion increased. The macro-mechanical properties and microstructure of RPC140 after autoclave curing were the best and showed the strongest resistance capacity to composite salt erosion, compared with those of C70 and RPC110 of standard curing. Finally, according to Weibull's statistical damage theory, a triaxial compression damage constitutive model of concrete under composite salt erosion was established and verified by experiments.

GEOMETRY ASSESSMENT ON THE SLOPE STABILITY OF MANYAR POND

Lateritic soil was treated with 0%, 4%, 8%, 12%, and 16% Rice Husk Ash (RHA) by dry soil weight to determine its consolidation properties. Test carried out include particle size distribution, specific gravity, compaction test with varying compactive efforts (British Standard Light (BSL), West African Standard (WAS) as well as British Standard Heavy (BSH)) and consolidation test. Samples for consolidation test were compacted and then cured for 7, 28 and 56 days; then subjected to one dimensional consolidation testing to observe the influence of curing period and compactive effort on its consolidation characteristics. Index tests showed improved geotechnical properties. The Maximum Dry Density (MDD) for BSL compaction decreased with a rise in RHA content from 1.72 to 1.42 Mg/m3 while optimum moisture content (OMC) increased from 16.5% to 27.3% with rise in RHA doses from 0% up to 16%. Similar trend was observed for WAS and BSH energies. Pre-consolidation pressure rise with increment in RHA content and also with increase in both compactive efforts and curing period with few exceptions. At 12% RHA content, Pre-consolidation pressure increased from 65 to 66.5 kN/m2 at 7 days and 56 days respectively. Increase in RHA content caused a decrease in Compression Index and Swelling Index. Compression Index also decreased with increase in both compactive efforts and curing period. There was no observed trend in the Swell Index with curing period. As the compactive efforts increased, the swell index decreased. The RHA reduced the Coefficient of Volume Compressibility (Mv) and the Coefficient of Consolidation (Cc). Curing period and compactive effort have no effect on Mv and Cc. Based on the results obtained, curing period at least 28 days using up to 12% RHA compacted at energy level of BSH improved the properties of the treated soil and can be used for geotechnical engineering applications like embankment or rural roads.

Investigation of mechanical strength and permeability characteristics of pervious concrete mixed with coral aggregate and seawater

The availability of the conventional raw materials required to produce pervious concrete on sea islands remote from the mainland is lacking, which could be alleviated by utilizing marine resources. This study aimed to develop seawater coral aggregate pervious concrete (SCAPC) by utilizing coral waste and seawater and assess the potential application of this method to sea islands. The SCAPC specimens were designed with different coral aggregate sizes (2.36–4.75 mm, 4.75–9.5 mm) and aggregate/binder ratios (2, 2.5, 3), and the addition of 10 % of sea sand. The physical properties (hardened density and porosity), mechanical strengths (compressive and splitting tensile strengths), water permeability, and sulfate attack resistance were investigated. The failure surface under mechanical loading and the microtopography between matrix and coral aggregate of SCAPC samples were also characterized. The results showed that the compressive strength and water permeability coefficient of the resulting SCAPCs at 28 days with a porosity ranging from 16.9 % to 33.5 % could reach 6.2–18.5 MPa and 12.9–26.5 mm/s, respectively. This not only satisfied the ACI 522R-recommended values for pervious concrete applicable to pedestrian road areas, but the samples demonstrated excellent permeability. The SCAPC specimens manufactured with aggregate/binder ratios of 2.5 incorporating 10 % sea sand were found to achieve the required balance between compressive strength (11.8–12.5 MPa) and water permeability coefficient (19.6–20.9 mm/s). The failure patterns of the SCAPC samples presented a markedly different complete fracture of coral aggregate point from that of traditional aggregate pervious concrete, ascribing this variation to the characterized fragility of coral aggregate and intensified interfacial adhesion.

Numerical Modeling for Prediction of Compression Index from Soil Index Properties in Jimma town, Ethiopia

In this study, correlations are developed to predict compression index (Cc) from index parameters so that one can be able to model Jimma soils with compression index using simple laboratory tests. Undisturbed and disturbed soil samples from twelve different locations in Jimma town were collected. Laboratory tests like specific gravity, grain size analysis, Atterberg limit, and one-dimensional consolidation test for a total of twenty-four test samples were conducted. From one-dimensional consolidation tests, compressibility soil parameters (Cc and Cs) are determined. From the results of limited tests, an indicative good correlation is observed between Cc and LL, PL, and PI. However, a Poor correlation is developed between Cc and PL when related to the other parameters. The developed correlations will be important inputs in modeling Jimma clay soils with regression model and Artificial neural networks (ANN) analysis using simple index tests. In addition, the results of this study can serve as a basis for further study of such correlations on different clay soils in the country. In this study, regression analysis was used to explore the significance of individual independent (index) soil properties. Regression model and correlation of compression index for liquid limit, plastic limit, and plasticity index were obtained from the linear regression analysis and ANN. This correlation will be helpful for geotechnical engineers in developing the coefficient of compression (Cc) value of expansive/clay soil from index properties. Finally, based on the general findings of the study, suitable recommendations have been forwarded.

Enhancing the Dewaterability of Oily Cold Rolling Mill Sludge Using Quicklime as a Conditioning Agent.

The high moisture and viscosity characteristics of oily cold rolling mill (CRM) sludge led to limitations in its recycling. In this paper, the results of using quicklime as a conditioning agent to improve the dewaterability of the oily CRM sludge cake were reported. Quicklime was selected as the best conditioning agent through conditioning-dewatering experiments because it could effectively reduce the viscosity of oily CRM sludge and improve the dewaterability of the oil sludge filter cake. The optimal conditioning effect was obtained when the quicklime dosage was 10%, the temperature was 60 °C, the liquid/solid ratio was 1.5:1, and the time was 30 min. The reduction of specific resistance to filtration was 95.9%, and the coefficient of compressibility of the filter cake decreased from 1.11 to 0.89. The dewatering rate increased from 9.0 to 52.6%. The oily CRM sludge cake formed an incompressible rigid porous structure because of conditioning with quicklime. In addition, after conditioning with quicklime, the oil content, chemical oxygen demand, and turbidity of the filtrate decreased, and the composition of the dried filter cake met the requirements of ironmaking raw materials. Using quicklime to condition the oily CRM sludge provided a green approach to waste recovery and sustainable management.

Effect of temperature and alkyl chain length on the physicochemical properties of pyridinium bis(trifluoromethylsulfonyl)imide-based ionic liquids

Densities, refractive indices, viscosities, surface tensions and speeds of sounds were measured and discussed for [Cnpy][[NTf2] (n=2,4,6) and [Cnmpy][[NTf2] (n=2,3,4) as a function of temperature and atmospheric pressure. As expected, all properties decrease with increasing temperature, with viscosity being the property most affected by temperature, while surface tension and refractive index being the properties least affected by temperature. Linear correlation was used to calculate the density, speed of sound, surface tension and refractive index as a function of temperature. The viscosity is correlated using Vogel-Flutcher-Tamman (VFT) equation. From the experimental density data, the coefficients of thermal expansion and the isentropic compressibility coefficients were calculated. The Guggenheim equation was used to calculate the critical temperatures. Moreover, the effect of the alkyl chain length of the investigated ionic liquids on the measured thermophysical properties is discussed.

Feasibility of improving wastewater sludge dewaterability by combination of cationic polyacrylamide and synthetic fibers for resource utilization

As a by-product of wastewater treatments, sewage sludge possesses great value but its high moisture content impedes the resource recovery. Chemical conditioners are required prior to mechanical dewatering, and they are important in dewatering operations. On the other hand, synthetic fibers have good compression properties and can help sludge to build qualified sludge cake in mechanical dewatering process. In this study, we investigated the synergistic effects between CPAM and synthetic fibers, which could improve the wastewater sludge dewaterability and resource utilization. The sludge water content decreased from 96.2 % to 65.9 % after conditioning with the combination of CPAM at 1 mg∙g−1 DS combined with PP at 0.15 g∙g−1 DS. The combination of CPAM and fiber increased the zeta potential of sludge from −12.5 mV to −5.12 mV and decreased the compressibility coefficient of sludge cake from 1.13 to 0.89, achieving the effect of destabilizing the system and enhancing the rigidity of sludge cake. EPS analysis showed that the association of CPAM with fiber acted as an aid to dewatering mainly through the disruption of TB-EPS. In addition, the dry basis calorific value (35%) reached 6676 kJ∙kg−1, indicating the feasibility of subsequent resource utilization. In conclusion, this study provided a new method and its underlying theory for deep sludge dewatering and wastes reutilization.

Integrated effects of concrete samples size and fibers amount on compressive strength of high‐ and ultra‐high strength concretes based on reactive powders

AbstractThe paper presents integrated effects of concrete samples size and fibers amount on compressive strength of high‐ and ultra‐high strength concretes based on reactive powders. Ready to use the self ‐ compacting mix of high‐performance concrete, was applied. The main aim of the work was to determine compressive strength correlation coefficients for size of cubic samples and integrated compressive strength correlation coefficients for the size of cubic samples including fibers ratio. The article presents the results of experimental tests of compressive strength for 3 sizes of cubic samples, i.e. 40, 100, and 150 mm, with the application of the steel fibers ratio of 0%, 2%, 4% for each sample size. Concrete air content and cone flow test studies were performed for all research series. The obtained results show a diversified influence of the size of the samples and the amount of steel fibers on the results of concrete compressive strength of high‐ and ultra‐high strength concretes based on reactive powders. Namely, the compressive strength correlation coefficient for the size of cubic samples was determined in the range 1.0–1.3, while the integrated compressive strength correlation coefficient the for size of cubic samples including fibers ratio is in the range 1.0–1.47.

Improvement of Image Compression by Changing the Mathematical Equation Style in Communication Systems

Compression is an essential process to reduce the amount of information by reducing the number of bits; this process is necessary for uploading images, audio, video, storage services, and TV transmission. In this paper, image compressions with losses from this action will be shown for some common patterns. The compression process uses different mathematical equations that have different methods and efficiencies, so some common mathematical methods for each style are presented taking into consideration the pros and cons of each method. In this paper, it is demonstrated that there is a quality improvement by applying anisotropic interpolation to edge enhancement for its ability to satisfy the dispersed data of the propagation process, which leads to faster compression due to concern for optimum quality rather than fast algorithms. The test images for these patterns showed a discrepancy in the image resolution when the compression coefficient was increased, as the results using three types of image compression methods proved a clear superiority when using “partial differential equations (PDE)”.

Mechanical properties and microscopic characterization of cement stabilized calcareous sand modified by nano SiO2

The accessible crushing property of calcareous sand leads to poor mechanical properties. Cement is usually used for solidification treatment in engineering. Nano-SiO2 (NS) can further improve the strength of cement-stabilized calcareous sand (CCS). In this study, the mechanical research of NS modified CCS is carried out through unconfined compression strength (UCS) test, split tensile strength (STS) test, and one-dimensional consolidation (ODC) test. The results show that when the CCS was solidified with 4.5‰ NS, the unconfined compressive strength reaches the maximum after 7–14 days of solidification, and the strengthening effect of NS is reflected in the early hydration stage. The addition of NS increased the splitting tensile strength at 7 days and 14 days by 100% and 48%,respectively. The ratio of splitting tensile strength to unconfined compressive strength was about 0.11, which was consistent with the curing law of solidified soil. Moreover, the addition of NS can reduce the compression coefficient of the sample, improve the compression modulus, and improve the compressive deformation resistance of CCS. The scanning electron microscopy (SEM) was used to study the microscopic mechanism. SEM test showed that the addition of NS produced more needle-like hydrates, and the nucleation effect of NS made the hydrates more tightly cemented. The porosity was obtained after the binary processing of SEM images, and the relationship model between the microstructure parameter porosity and UCS was established.

GREEN SYNTHESIS OF CHROMIUM OXIDE NANOPARTICLES - STUDY OF ITS ANTIBACTERIAL, PHOTOCATALYTIC AND THERMODYNAMIC PROPERTIES

An endeavor has been made to report the herbal synthesis of chromium oxide (Cr2O3) nanoparticles using aqueous extract of nigella sativa seed extract as a capping agent and chromic sulphateas a precursor material. The structural, morphological and optical properties of the Cr2O3 nanoparticles were analyzed by X - ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM) and UV- Visible spectroscopy. The antibacterial efficacy of chromium oxide nanoparticles was tested against Staphylococcus aureus, Klebsiella pneumonia and Pseudomonas aeruginosa. The photocatalytic activity of biosynthesized Cr2O3 nanoparticles was evaluated by degrading methylene blue dye and Congo red dye under the irradiation of visible light. Apart from this, ultrasonic velocity, density and viscosity were measured for different concentrations of Cr2O3 nanofluid using ultrasonic techniques. Thermoacoustical such as adiabatic compressibility, free length, acoustic impedance, relaxation time and absorption coefficient values are computed from the measured data and the results are interpreted in terms of particle - fluid interactions.

Insight into the effect of calcium carbonate filler on the dewatering performance of simulated pulp & paper mill sludge

The dewatering of large amount of industry sludge is one of the significant environmental problems in the pulp and paper industry. Calcium carbonate fillers are an important component in primary sludge from paper mills. In this paper, the role of precipitated calcium carbonate (PCC) on the dewaterability of simulated mixed paper mill sludge (the mixture of PCC and secondary sludge) without and with FeCl3 conditioning was studied. The results showed that when the PCC content increased from 0 to 600 mg/g dry sludge (DS) without FeCl3 conditioning, the moisture content (MC) and the specific resistance to filtration (SRF) decreased from 89.4% and 3.1 × 1013 m/kg to 66.7% and 2.4 × 1012 m/kg, respectively. However, when the PCC content was high enough (> 444 mg/g DS), the effective moisture content (MC*) changed little and the net sludge solid yield (YN) decreased, indicating that the non-conditioning effect of PCC dominated at high PCC content. Furthermore, increasing PCC content reduced the compressibility coefficient, although the change was insignificant from 1.06 to 0.91. When FeCl3 was used as the chemical conditioner, FeCl3 and PCC had additive effects on improving the sludge dewaterability (such as MC, SRF and compressibility). The improving mechanism of PCC on the sludge dewaterability can be explained by the release of Ca2+ from PCC caused by lower pH, the bridging effect of multivalent cation and the formation of more rigid sludge flocs.

Design and performance optimization of alkali-activated waste coal bottom ash/slag porous concrete

When alkali-activated slag material is used in porous concrete, it has the problems of short setting time and poor operability. In this paper, the effect of coal bottom ash content on the rheological properties, the mechanical properties, porosity, permeability coefficient, and PFT of AACS-PC of the paste was investigated. The results showed that the fluidity and porosity of the paste with a water–solid ratio of 0.35 were positively correlated with the coal bottom ash content, but negatively correlated with the PFT. When the content of coal bottom ash was 20 wt% and the waterglass modulus was 1.4, the compressive strength of AACS-PC can reach 22.1Mpa and the water permeability coefficient of AACS-PC was 2.9 mm/s. Both the compressive strength and water permeability coefficient could meet the requirements of the standard of ASTM and JIS A. The addition of CBA can effectively improve the operability of alkali -activated materials in the preparation of porous concrete.

Spatial variation of permeability and consolidation behaviors of soil using ordinary kriging method

The present study is aimed at finding out spatial distribution of permeability characteristic of soil using ordinary kriging method at any location using the data from a few boreholes at NIT (National Institute of Technology) Patna Bihta campus. Kriging is also popularly known as BLUE (i. e. Best Linear Unbiased Estimator) which can be used to interpolate the data obtained from a few locations to get an estimate of any parameter at other locations throughout the study area. In the present work, soil samples collected from eight boreholes have been tested to obtain various geotechnical properties including liquid limit (LL), plastic limit (PL), plasticity index (IP), coefficient of volume compressibility (mv) etc. These values have been used as inputs in an Ordinary Kriging model to calculate coefficient of consolidation (Cv) and coefficient of permeability (k) throughout the NIT Patna, Bihta campus and build contour plots of (Cv) and (k) over the NIT Patna campus to show their spatial variation. The novelty of the current work lies in the first time proposed method for developing the spatial distribution of(Cv) and(k). Markov correlation matrix has been used to develop the correlation behavior of the parameters considering different values of correlation length. In the present study, it is found that the coefficient of consolidation Cv of soil ranges 10−8 (m2/sec). The Kriged values of k are in the range of 10−11 to 10−10 (m/s). Finally, semi-variogram have been shown to display the auto-correlation of the measured data points and cross-validation of data set which establish that the Kriged data are reasonably correlated. Also, various error estimators such as Mean Error, Root Mean Square Error, Average Standard Error, Root Mean Square Standard Error, Mean Standard Error have been calculated using the Kriged data points over the entire area and, it is found that the error level in the predicted Kriged data are reasonably small.

Sustainable use of soda lime glass powder (SLGP) in expansive soil stabilization

The focus of this experimental study is to ameliorate the engineering behavior of Palygorskite-rich medium Expansive soils (ES) by utilizing soda lime glass powder (SLGP). The hydrophilic ES are problematic and tend to damage the pavements, boundary walls, and slab-on-grade members Whereas, the accumulation of huge amounts of SLGP is responsible for multitude of environmental issues. Therefore, SLGP was added to the ES using various dosage levels (0 %, 6 %, 10 %, 14 %, 16 %, 18 %, and 22 % by dry weight of the ES to assess the compaction, consolidation and strength characteristics by performing geotechnical laboratory tests. Also, the effect of curing on th unconfined compressive strength of ES (UCS-ES) after 3, 7, 14, and 28 days was studied by considering the mineralogical changes. The microscopic mechanisms of the virgin ES and the SLGP-treated mixtures was evaluated by X-ray fluorescence (XRF), X-ray diffraction (XRD), and scanning electron microscopy (SEM) analyses. The results revealed that, plasticity dropped by almost 80 % (due to filler effect, cohesionless character, and higher silica amount of the SLGP), MDD increased from 18.25 to 19.16 kN/m3, and the OMC lowered down (due to the reduction in volume of clay minerals and interlayer spaces). With increasing SLGP dosage levels the coefficient of compression (Cc) decreased by 42.86 %, coefficient of volume (mv) by 60 %, coefficient of consolidation (cv) by 91.53 %, and the pre-consolidation pressures (Pc) witnessed an increase of 240 %. The UCS-ESunsoaked values exceed than the UCS-ES soaked values, particularly at early days of curing (1–7 days) such that UCS-ESsoaked = 13 × UCS-ESsoaked after one day, whereas UCS-ESsoaked = 5.25 × UCS-ESsoaked after 28 days. Similarly, a remarkable improvement (of six -fold) in strength was recorded based on California bearing ratio (CBR) values with 16 % replacement of the SLGP additive. Also, the compactability and strength characteristics were significantly improved and the plasticity plummeted due to formation of C-S-H and C-A-H compounds. Thus, the inclusion of 16 % SLGP in the medium ES was found as the optimum amount in reducing plasticity, improving consolidation characteristics and imparting strength.

Enhanced dewaterability of sludge by Fe(II)-sludge biochar activate persulfate

ABSTRACT Sludge biochar supported Fe(II) (Fe(II)-SBC) was successfully prepared using waste activated sludge as peroxydisulfate (PDS) activator to condition sludge for deep dewatering. The experimental results showed that Fe(II)-SBC with FeO on it could effectively active PDS to produce SO 4 − ⋅ and HO ⋅ . The radicals could destroy the structure of sludge cells and extracellular polymeric substance (EPS), transformed the hydrophilic and tightly bound EPS into soluble-EPS, degrade partial proteins and polysaccharides and released bound water. The negatively charged groups on sludge floc were dripped off by SO 4 − ⋅ / HO ⋅ or neutralized with Fe2+, Fe3+, H+, or Fe(II)-SBC, leading to an increase in zeta potential to −2.24 mV and sludge destabilization. The residual Fe(II)-SBC served as a skeleton builder that decreased the compression coefficient of the sludge cake to 0.75. Under the combined functions, the CST and SRF were reduced by 70% and 82.7%, respectively, and Wc was reduced to 72.4%. The byproducts of Fe3+ and SO4 2- finally remained in sludge cake in the form of NaFeSi2O6 and CaSO4.