The removal of cesium from an aqueous solution by an adsorption–microfiltration (AMF) process was investigated in jar tests and lab-scale tests. The adsorbent was K
2Zn
3Fe(CN)
6
2. The obtained ...cesium data in the jar test fit a Freundlich-type isotherm well. In the lab-scale test, the mean cesium concentration of the raw water and the effluent were 106.87
μg/L and 0.59
μg/L, respectively, the mean removal of cesium was 99.44%, and the mean decontamination factors (DF) and concentration factors (CF) were 208 and 539, respectively. The removal of cesium in the lab-scale test was better than that in the jar test because the old adsorbents remaining in the reactor still had adsorption capacity with the premise of no significant desorption being observed, and the continuous renewal of the adsorbent surface improved the adsorption capacity of the adsorbent. Some of the suspended solids were deposited on the bottom of the reactor, which would affect the mixing of adsorbents with the raw water and the renewing of the adsorbent surface. Membrane fouling was the main physical fouling mechanism, and the cake layer was the main filtration resistance. Specific flux (SF) decreased step by step during the whole period of operation due to membrane fouling and concentration polarization. The quality of the effluent was good and the turbidity remained lower than 0.1
NTU, and the toxic anion, CN
−, could not be detected because of its low concentration, this indicated that the effluent was safe. The AMF process was feasible for practical application in the treatment of liquid waste containing cesium.
► Mill scale on carbon steel rebar contains voids, crevices and cracks. ► Crevices between mill scale and steel provide sites for pit initiation. ► As-received rebars have low chloride thresholds due ...to mill scale crevices. ► Mill scale has large variability in its physical and chemical properties. ► Variability in chloride thresholds may be attributed to the mill scale variability.
Electrochemical experiments have shown that mill scale on carbon steel rebar affects corrosion initiation and variability associated with chloride-induced depassivation thresholds. In this study, scanning electron microscopy and focused ion beam microscopy were used to investigate the properties of mill scale and its effect on chloride thresholds of the underlying steel. The variability found in the literature for chloride thresholds is suggested to result, in part, from the variability in the physical and chemical properties of mill scale. A crevice corrosion mechanism is proposed to explain why as-received rebar is more susceptible to depassivation than rebar without mill scale.
Analytical TEM techniques were used to characterize passive film on carbon steel and how it breaks down with chloride addition. Before chloride addition, the thicknesses of the oxide films on rebars ...were found to be uniform between 5 and 13nm. The films consisted mainly of iron oxides that included nano-crystalites of FeOOH with an epitaxial relationship to the metal surface. Elements from the passivating solutions were located in regions of the oxide closest to the free surface. With the addition of chloride at concentrations below depassivation thresholds, there was evidence for change in the oxide closest to the free surface, but generally the oxides were similar to those grown before chloride addition. After exposure to chloride concentrations above depassivation thresholds, the oxide films were no longer uniform, with parts of the surface bare, and the average oxide thickness reduced. Pitting and enhanced corrosion were seen to accompany cementite lamella.
Precision inspection has been widely used in manufacturing to measure the dimensional accuracy of parts and products to meet the quality requirements. For regular geometric features, ...coordinate-measuring machines (CMM) can be used effectively to assess the accuracy and tolerances. For parts with free-form surfaces, the inspection becomes complex. Therefore, numerous researches have been carried out to tackle both fundamental and application issues concerning free-form surface inspection. In addition to academic research, some commercial packages have also been developed.
This paper provides a comprehensive literature review of methodologies, techniques and various processes of inspections of parts with free-form surfaces. The specific topics cover: measurement data acquiring methods including contact and non-contact measurement approaches; inspection planning; geometric description methods of design models or measurement data; and, the free-form surface localization and comparison techniques, which are emphasized in this paper and mainly include the establishment of corresponding relationship, 3D transformation solving, measurement data to design model comparison or surface to surface distance calculations. Other issues, such as the influence factors to the localization/registration process, definition and inspection of free-form surface tolerance, and discussions on the functions of some commercial inspection packages available on market, are also discussed.
Objective: To investigate the changes of platelet mitochondrial mass and quantity during perioperative period in elderly patients, and assess their predictive values on the occurrence of ...postoperative delirium (POD). Methods: In this prospective study, 162 elderly patients scheduled for abdominal surgery under general anesthesia were enrolled from November 2021 to January 2022 in Nanjing Drum Tower Hospital Affiliated to Nanjing University Medical School. Among them, 20 patients 10 males, 10 females, aged (71.4±6.8) years developed POD within 3 days after surgery (POD group), and another 20 patients12 males, 8 females, aged (67.7±5.3) years who did not develope POD were selected as controls (control group) using propensity score matching method. Blood samples were collected preoperatively, at the end of surgery and on the first postoperative day. Platelets were extracted and mitochondrial mass was detected with flow cytometry. Transmission electron microscopy was used to determine mitochondrial quantity.
The purpose of the present study was to investigate the potential neuroprotective effect of neuroserpin (NSP) on acute retinal ischemic/reperfusion-induced (IR) injury. An IR injury model was ...established by elevating intraocular pressure (IOP) for 60 minutes in wild type and tPA-deficient (tPA-/-) mice. Prior to IR injury, 1 μL of 20 μmol/L NSP or an equal volume of bovine serum albumin (BSA) was intravitreally administered. Retinal function was evaluated by electroretinograph (ERG) and the number of apoptotic neurons was determined via TUNEL labeling. Caspase-3, -8, -9,poly (ADP-ribose) polymerase (PARP)and their cleaved forms were subsequently analyzed. It was found that IR injury significantly damaged retinal function, inducing apoptosis in the retina, while NSP attenuated the loss of retinal function and significantly reduced the number of apoptotic neurons in both wild type and tPA-/- mice. The levels of cleaved caspase-3, cleaved PARP (the substrate of caspase-3) and caspase-9 (the modulator of the caspase-3), which had increased following IR injury, were significantly inhibited by NSP in both wild type and tPA-/- mice. NSP increased ischemic tolerance in the retina at least partially by inhibiting the intrinsic cell death signaling pathway of caspase-3. It was therefore concluded that the protective effect of neuroserpin maybe independent from its canonical interaction with a tissue-type plasminogen activator.
Ammonia is one of the most abundant alkaline trace gases in the atmosphere, which is one of the important factors affecting atmospheric quality. Excessive application of nitrogen fertilizer is the ...main source of global ammonia emissions, which not only exacerbate greenhouse gas emissions, but also leads to eutrophication of water bodies. In this paper, the basic principle, the operation process, the advantages and disadvantages, and the previous research results of the method are summarized in detail, including the enclosure method, the venting method, the continuous airflow enclosure method, the wind tunnel method and the micro-meteorological method. So as to provide a theoretical basis for selecting the appropriate method for determination of ammonia volatilization.
In an attempt to improve the design of products and reduce design changes, cost, and time to market, concurrent engineering or life cycle engineering has emerged as an effective approach to ...addressing these issues in today's competitive global market. As over 70% of the total life cycle cost of a product is committed at the early design stage, designers are in a position to substantially reduce the life cycle cost of the products they design, by giving due consideration to life cycle cost implications of their design decisions. Increasing recognition of cost competition has spurred the development of methodologies such as design for manufacturability, design for assembly (DFA), design for producibility, design for maintainability and design for quality, in the design for 'X' realm. Although these methodologies have for the most part proven successful in reducing cost, the design evaluation criterion in most of these methodologies is not cost. Therefore methodologies and tools are needed to directly provide cost information to designers. Life Cycle Cost (LCC) analysis provides a framework for specifying the estimated total incremental cost of developing, producing, using, and retiring a particular item. This paper looks at the issues of LCC analysis and the tools that have been developed to provide engineers with cost information to guide them in design.
Wide plate, wide plate weld, pipeline girth weld and plate welded of panel used to the storage tank were wholly stretched by 2000T wide plate tensile test machine when using the related fixture. ...Tensile strength, initiation crack position of the joint crack, tolerance of the existing defects of welded joint, possibility of the crack propagation and fracture were studied. Their weak links were found, the formation of defects were avoided by welding technology and technical means. The closed loop control was realized by using advanced servo valve and high performance measure and control system, computer technology was used fully, multifunctional test control of the machine was realized. A number of servo cylinder precise synchronous control loading mechanism was adopted by 2000 T wide plate tensile testing machine, the design of its loading mode, servo cylinder, sensor installation layout and combined structure of super power sensor was the first in China, which created a platform for the development of large structure testing machine in the future.
PDF
