Scalar fields coupled to the Gauss-Bonnet invariant can undergo a tachyonic instability, leading to spontaneous scalarization of black holes. Studies of this effect have so far been restricted to ...single black hole spacetimes. We present the first results on dynamical scalarization in head-on collisions and quasicircular inspirals of black hole binaries with numerical relativity simulations. We show that black hole binaries can either form a scalarized remnant or dynamically descalarize by shedding off its initial scalar hair. The observational implications of these findings are discussed.
This research investigated the comparative efficacy of sulfamic acid (SA) and phytic acid (PA), both individually and in combination, for treating potential foodborne pathogens and pre-formed ...foulants. Pathogens studied included Listeria monocytogenes, E. coli DH5α, Salmonella typhimurium, Staphylococcus aureus, and vegetative Bacillus cereus, in suspended aqueous solutions, as well as Pseudomonas aeruginosa biofilm on quartz glass surfaces. Inactivation kinetics for Listeria monocytogenes revealed concentration-dependent rate constants (k) of 6.6(±0.2) × 10−6 M and 2.8(±0.1) × 10−8 M for single treatments of SA and PA, respectively, and ranged from 6.9(±0.3) to 50.7(±2.3) × 10−6 M for combined treatments with PA pre-treatment concentrations of 75–758 μM. Observable cellular abnormalities in Listeria monocytogenes, such as membrane vesiculation, chelation, cellular disruption, biomolecule leakage, and lipid peroxidation, were identified after exposure to PA or SA, either individually or in combination. The optimized combined treatment of PA and SA achieved significant removal (i.e., >3-log; 99.9%) of potential foodborne pathogens under simulated food-washing process conditions. Additionally, over 90% descaling efficacy was observed for pre-formed foulants such as CaCO3 precipitates and Pseudomonas aeruginosa biofilm on quartz glass surfaces with the combined treatment. These findings provide novel insights into the versatile utility of PA and SA for optimizing combinational water disinfection systems and addressing (in)organic foulant scaling on surfaces in the food processing industry.
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•Kinetics and mechanisms of Listeria monocytogenes inactivation were assessed.•Combined treatment with PA and SA exhibited higher rate constants (k).•Discernible abnormalities in physiological and biochemical parameters were observed with the treatment of PA and SA.•Five foodborne pathogens were removed under simulated fresh washing processes.•Surface scales of biofilms or calcium carbonate precipitates were mitigated.
Onion bulbs contain outer papery dry peel which is rich with industrially important high-value compounds. Removal of dry peel/scale of onion is the common practice during bulb processing, storage and ...marketing. A conventional manual method of scale removal involves huge labour, drudgery and means of environmental pollution. An onion descaler machine has been therefore developed to mechanize this operation, reduce drudgery and effectively collect the dry scales for industrial use. The operating parameters of the developed machine were optimized for its best performance using RSM. During optimization study, roller speed, roller slope and hopper opening were taken as independent variables. The performance of the machine was evaluated through descaling efficiency and descaling loss. During experimentation, descaling efficiency and descaling loss were obtained in the range of 35.92–98.55% and 0.82–9.07%. The optimum performance of the machine was obtained at 450 rpm roller speed, 2% roller slope and 380 mm of the hopper opening with maximum descaling efficiency (88.29%) and minimum descaling loss (3.65%). The optimization of the onion descaler parameters and their statistical relation provided the necessary information on the combination of material-machine alignment, and design parameters for enhanced descaling efficiency.
As an environmentally friendly technology, electrochemical descaling has received extensive attention and research. In the traditional electrochemical descaling system, the precipitated scale is ...affected by several factors and only a portion of these ions can crystallize and grow into the scale layer on the cathode surface. In addition, the alkalinity ions are severely depleted by neutralization reactions, resulting in a decrease in pH value and unfavorable for the crystallization of scale. A confined crystallization membrane (CCM) for inducing scale crystallization is set to the traditional electrochemical descaling system in this paper, which weakens the negative effect of concentration polarization on mass transfer, providing an environment with high pH and low water flow interference for the crystallization of scale. Cyclic electrolysis experiments show that the addition of CCM greatly increases the amount of scale deposition, with a maximum of 60.26 g·h−1·m−2. The scale consumption per unit weight is saved by more than 50 % after adding the CCM, the values of Ryznar Stability Index (RSI) and Langelier Saturation Index (LSI) of the solution can reach the ideal range in a shorter time. The cleaning cycle of CCM is about 144 h, and the scale can be removed by pickling, thus restoring the enhanced descaling function of CCM.
•CCM significantly decreased the diffusion of OH−.•CCM promotes scale crystals generation and enhance the descaling efficiency.•The scale cleaning cycle of cathode can be prolonged effectively.•The scaling tendency of circulating cooling water is significantly weakened.
Heat exchangers represent vital equipment for the production and heat recovery in thermal desalination processes. However, with operation under scale control practices, scale growth reduces the ...performance and efficiency. To restore this performance, acid cleaning is the most adopted and efficient descaling method. Usually, strong mineral acids are used for acid cleaning and corrosion inhibitor addition represents a necessity to protect the underlying metal. Development of cost–effective and low toxic corrosion inhibitors for acid cleaning purpose has, therefore, becomes an essential area of research. In the present work, acid cleaning corrosion inhibitors research and development efforts reported in scientific publications and patent inventions over the last thirty years is reviewed. The review strictly considers works directly related to acid cleaning (descaling) publications rather than the usual acid corrosion inhibition of metals. Critical knowledge gaps are identified and future research perspectives are highlighted.
•Scientific publications and Patents are reviewed for acid cleaning corrosion inhibitors over a thirty–year period.•Strength and weakness of corrosion inhibitor chemistries for multistage flash (MSF) desalination heat exchanger alloys are examined.•Knowledge gaps are identified.•Future research directions are highlighted.
The surface of carp is easily damaged during the descaling process, which jeopardizes the quality and safety of carp products. Damage recognition realized by manual detection is an important factor ...restricting the automation in the pretreatment. For the commonly used methods of mechanical and water‐jet descaling, damage area recognition according to the hyperspectral data was proposed. Two discrimination models, including decision tree (DT) and self‐organizing feature mapping (SOM), were established to recognize the damaged and normal descaling area with the average spectral value. The damage‐discrimination model based on DT was determined to be the optimal one, which possessed the best model performance (accuracy = 96.7%, sensitivity = 96.7%, specificity = 96.7%, F1‐score = 96.7%). Considering the efficiency and precision of damage‐area recognition and visualization, the principal component analysis (PCA) combined with pixel values statistical analysis was used to reduce the dimension of hyperspectral images at the image level. Through statistical analysis, the value 0 was used as the threshold to distinguish the normal area and the damaged area in the PC image to achieve preliminary segmentation. Then, the spectral values of the initially discriminated damage area were input into the DT discrimination model to realize the final discriminant of damaged area. On this basis, the position information of the damaged area could be used to realize the visualization. The final visualization maps for mechanical and water‐jet descaling damage were obtained by image morphology processing. The average recognition accuracy can reach 94.9% and 90.3%, respectively. The results revealed that the hyperspectral imaging technique has great potential to recognize the carp damage area nondestructively and accurately under descaling processing.
Practical Application
This study demonstrated that hyperspectral imaging technique can realize the carp damage area detection nondestructively and accurately under descaling processing. With the advantages of nondestructive and rapid, hyperspectral imaging system and the method can be widely expanded and applied to the quality detection of other freshwater fish pretreatment.
Calcareous scales can form in industrial and domestic pipelines, heat exchangers, desalination plants, or cooling towers, causing obstruction and flow reduction, high-pressure drops, low heat ...transfer coefficients, and other harmful effects, resulting in a negative economic impact. The composition of calcareous scales varies depending on the type and quality of the water in which they form and usually consists of carbonate minerals. In this study, we evaluated an organic acid mixture that is environmentally friendly, descaling solution to remove calcareous scales on embedded domestic pipelines. The results presented include speciation diagrams of the descaling solution at different concentrations in contact with calcium carbonate, using the software MEDUSA. The results indicate that stable citrate and phosphate complexes are formed at 1 < pH < 4. XRD and FTIR analyses of the recrystallized scales from embedded pipelines in the descaling solution show different calcium carbonate polymorphs. The LPR technique allows us to calculate the corrosion rates of embedded carbon pipeline sections in contact with the descaling solutions at different concentrations. A corrosion rate reduction of 39% was observed for 0.1 M descaling solution compared with 0.1 M HCl.
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•Superior removal rates of EC-FC system compared with EC system.•Effective interception of scale particles in effluent of EC module.•The function of FC module to alleviating ohmic ...heat from EC reactor.•More efficient operation in high current density of EC-FC system than EC.
Targeting for the problems in industrial circulating cooling water system resulted from scale formation, researchers have proposed a variety of treatment solutions, among which electrochemical descaling is one of the most promising technology. At present, the main barrier in electrochemical scale removal is relatively insufficient treatment efficiency. One possible reason for this is that the scale particles generated by electrochemical process cannot be effectively deposited on the cathode of the reactor but flow out of the electrochemical reactor. To this problem, this paper proposed a coupled system that connected the filter crystallization module after the electrochemical descaling process. By doing so, it was expected to filter and intercept scale particles, thus improving the overall performance of treatment. The experimental results attested that the introduction of filtration crystallization (FC) system could improve the performance of electrochemical-filtration crystallization (EC-FC) system in hardness removal rate, alkalinity removal rate, total dissolved solids (TDS) removal rate and water sample temperature difference. With the promotion effect from FC system, the scale particles in the effluent from the EC system can be effectively intercepted, and inductive crystallization of the scale ions can be achieved for further purification. Different from EC system, the descaling efficiency of EC-FC system escalated continuously with the rise of current density, while decreased first and then went up with the shortening of hydraulic retention time. However, EC system determined the upper limit of the treatment performance of the whole system. It was because FC system can only deposit the scale particles that were not deposited on the cathode plate on the filler, but cannot react to produce new scale formation ions. Through our proposal and investigation, this work provides an original facile idea for the practical application of electrochemical scale removal technology with proved feasibility.
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