MIC in Circulating Cooling Water System

MIC is one of the main problems of circulating cooling water system. The direct economic loss by MIC is about 300 to 500 billion dollars. It is good to understand MIC in order to control MIC. Source and species of microorganisms was introduced firstly. There are three kinds of microorganisms in the system, including bacteria, fungi and algae. Species of these microorganisms are shown in the paper. Then, mechanisms of MIC are analysed. Although there is no universal mechanism of MIC, MIC is still mainly an electrochemical corrosion in nature. Meanwhile, the mechanisms on SRB and iron bacteria are introduced in details. At last, several methods of microorganisms control are put forward in the paper.

Microbiological Induced Corrosion on Brass in Recycling Cooling Water System Makeup by Reclaimed Water

The impacts of microorganism on brass corrosion were studied in static experiment in this paper. Two main factors, temperature and concentration ratio, were considered. According to the actual operation of recycling cooling water system, four temperatures (15℃, 25℃, 35℃ and 45℃) and four concentration ratios (1, 2.5, 3.5 and 4.5) were selected in the experiment. Corrosion potential, current density, average corrosion rate were measured by time. The results showed that: Microorganism often aggravated corrosion of brass during initial and final stages, but alleviated its corrosion at the middle time. With the extension of time that brass immersed in the solution, the microbes began to intensify the corrosion of the metal. When concentration ratios were 2.5 and 3.5 and temperature was 15℃, microbe promoted brass corrosion obviously and corrosion degrees.

Insight into phase structure-dependent soot oxidation activity of K/MnO_(2) catalyst

In the present study,two nanosized MnO_(2)with β and δ phase structures and potassium loaded MnO_(2)catalysts with varied K loading amounts (denoted as K/MnO_(2)) were prepared.Temperature programmed oxidation and isothermal reactions in loose contact modes were employed to examine the soot oxidation activity of the as-prepared catalysts.Characterization results show that as compared with β-MnO_(2),δ-MnO_(2)has larger surface area and higher content of hydroxyl groups.Upon K loading,abundant hydroxyl groups in δ-MnO_(2)effectively sequestrate K cation to form bound K species and free K species are available only at K loading above 3.0 wt.%.In contrast,the majority of K species present as free state in β-MnO_(2)even at a K loading of 1.0 wt.%due to its very low hydroxyl group content.The O_(2)temperature-programmed desorption (O_(2)-TPD) demonstrates that the catalysts with free K species exhibit strong ability in activating gaseous O_(2),whereas the catalysts only having bound K display minor O_(2)activation capability.As a result,despite of slightly lower activity of β-MnO_(2)than δ-MnO_(2),the K/β-MnO_(2)catalysts exhibit substantially higher activities than K/δ-MnO_(2)catalysts with identical K loadings.The finding in this study clearly demonstrates that for MnO_(2)based catalysts,the enhancement of catalytic activity for soot oxidation is highly K loading amount dependent and the dependency is strongly associated with the phase structure of MnO_(2).

The eccentricity enhancement effect of intermediate-mass-ratio-inspirals: dark matter and black hole mass

It was found that dark matter(DM) in an intermediate-mass-ratio-inspiral(IMRI) system has a significant enhancement effect on the orbital eccentricity of a stellar massive compact object, such as a black hole(BH),which may be tested by space-based gravitational wave(GW) detectors, including LISA, Taiji, and Tianqin in future observations. In this paper, we study the enhancement effect of the eccentricity for an IMRI under different DM density profiles and center BH masses. Our results are as follows:(1) in terms of the general DM spike distribution,the enhancement of the eccentricity is basically consistent with the power-law profile, which indicates that it is reasonable to adopt the power-law profile;(2) in the presence of a DM spike, the different masses of the center BH will affect the eccentricity, which provides a new way for us to detect the BH’s mass;and(3) considering the change in the eccentricity in the presence and absence of a DM spike, we find that it is possible to distinguish DM models by measuring the eccentricity at a scale of approximately 105 GM/c2.

The ringing of quantum corrected Schwarzschild black hole with GUP

Schwarzschild black holes with quantum corrections are studied under scalar field perturbations and electromagnetic field perturbations to analyze the effect of the correction term on the potential function and quasinormal mode(QNM).In classical general relativity,spacetime is continuous and there is no existence of the so-called minimal length.The introduction of the correction items of the generalized uncertainty principle,the parameterβ,can change the singularity structure of the black hole gauge and may lead to discretization in time and space.We apply the sixth-order WKB method to approximate the QNM of Schwarzschild black holes with quantum corrections and perform numerical analysis to derive the results of the method.Also,we find that the effective potential and QNM in scalar fields are larger than those in electromagnetic fields.

Testing the quantum effects near the event horizon with respect to the black hole shadow

In recent years,the study of quantum effects near the event horizon of a black hole(BH)has attracted extensive attention.It has become one of the important methods to explore BH quantum properties using the related properties of a quantum deformed BH.In this work,we study the effect of a quantum deformed BH on the BH shadow in two-dimensional Dilaton gravity.In this model,quantum effects are reflected by the quantum correction parameter m.By calculation,we find that:(1)the shape of the shadow boundary of a rotating BH is determined by the BH spin a,the quantum correction parameter m,and the BH type parameter n;(2)when the spin a=0,the shape of the BH shadow is a perfect circle;when a≠0,the shape is distorted;if the quantum correction parameter m=0,their shapes reduce to the cases of a Schwarzschild BH and Kerr BH,respectively;(3)the degree of distortion of the BH shadow is different for various quantum correction parameters m;with an increase in the parameter m,the boundary of the BH shadow expands;(4)the size of the BH shadow varies greatly with respect to various quantum deformed BHs(n),and the change in BH shadow shape caused by parameter n is similar to that caused by parameter m,which indicates that there is a"degenerate phenomenon"between the two parameters.Because the value of m in actual physics should be very small,the current observations of the event horizon telescope(EHT)cannot distinguish quantum effects from the BH shadow.In future BH shadow measurements,it will be possible to distinguish quantum deformed BHs,which will help to better understand the quantum effects of BHs.

Observational constraints on Rastall gravity from rotation curves of low surface brightness galaxies

Rastall gravity is a modification of Einstein's general relativity in which the energy-momentum conservation is not satisfied and depends on the gradient of the Ricci curvature.It is currently in dispute whether Rastall gravity is equivalent to general relativity(GR).In this work,we constrain the theory using the rotation curves of low surface brightness(LSB)spiral galaxies.By fitting the rotation curves of LSB galaxies,we obtain parameterβof the Rastall gravity.Theβvalues of LSB galaxies satisfy the weak energy condition(WEC)and strong energy condition(SEC).Combining theβvalues of type Ia supernovae and the gravitational lensing of elliptical galaxies on Rastall gravity,we conclude that Rastall gravity may be equivalent to general relativity.