During the production of Ti-bearing Al-killed ultra-low-carbon(ULC) steel, two different heating processes were used when the converter tapping temperature or the molten steel temperature in the Ruhrstahl–Heraeus(RH)...During the production of Ti-bearing Al-killed ultra-low-carbon(ULC) steel, two different heating processes were used when the converter tapping temperature or the molten steel temperature in the Ruhrstahl–Heraeus(RH) process was low: heating by Al addition during the RH decarburization process and final deoxidation at the end of the RH decarburization process(process-Ⅰ), and increasing the oxygen content at the end of RH decarburization, heating and final deoxidation by one-time Al addition(process-Ⅱ). Temperature increases of 10°C by different processes were studied; the results showed that the two heating processes could achieve the same heating effect. The T.[O] content in the slab and the refining process was better controlled by process-Ⅰ than by process-Ⅱ. Statistical analysis of inclusions showed that the numbers of inclusions in the slab obtained by process-Ⅰ were substantially less than those in the slab obtained by process-Ⅱ. For process-Ⅰ, the Al_2O_3 inclusions produced by Al added to induce heating were substantially removed at the end of decarburization. The amounts of inclusions were substantially greater for process-Ⅱ than for process-Ⅰ at different refining stages because of the higher dissolved oxygen concentration in process-Ⅱ. Industrial test results showed that process-Ⅰ was more beneficial for improving the cleanliness of molten steel.展开更多
To make high integrity lightweight metal castings,best practices are required in various stages of casting and heat treatment processes,including liquid metal composition and quality control,casting and gating/riser s...To make high integrity lightweight metal castings,best practices are required in various stages of casting and heat treatment processes,including liquid metal composition and quality control,casting and gating/riser system design,and process optimization.This paper presents best practices for liquid metal processing and quality assurance of molten metal in both melting and mold filling.Best practices for other aspects of lightweight metal casting will be published separately.展开更多
A testing system for evaluating cleanliness of ventilation ducts was constructed. Comparisons of four evaluation methods for quantifying the amount of dust on the inner surface of ventilation ducts are presented. The ...A testing system for evaluating cleanliness of ventilation ducts was constructed. Comparisons of four evaluation methods for quantifying the amount of dust on the inner surface of ventilation ducts are presented. The experimental results show that the wiping by solvent method is more efficient than that by the wiping method,especially used on low cleanliness duct surface. The gravimetric tape method is an efficient method of collecting dust samples on the duct surface with low amounts of dust,particularly used to check the cleanliness level after the cleaning work. The optical method can be set up rapidly and is useful for fieldwork measurements.展开更多
Based on analysis of a large data set and supplementary sampling and analysis for hazardous trace elements in coal samples from the Huainan Coalfield,a generalized contrast-weighted scale index method was used to esta...Based on analysis of a large data set and supplementary sampling and analysis for hazardous trace elements in coal samples from the Huainan Coalfield,a generalized contrast-weighted scale index method was used to establish a model to evaluate the grade of coal cleanliness and its regional distribution in the main coal seam(No.13-1)The results showed that:(1)The contents of Cr,Mn and Ni in the coal seam are relatively high and the average values are greater than 20μg/g.The contents of Se and Hg are at a high level while most other trace elements are at normal levels.(2)The cleanliness grade of the coal seam is mainly grade III-IV,which corresponds to a relatively good-medium coal cleanliness grade.However,some parts of the seam are at grade V(relatively poor coal cleanliness).(3)Coal of relatively good cleanliness grade(grade III)is distributed mainly in the regions corresponding to the Zhuji-Dingji-Gubei coal mines and in the eastern periphery of the Panji coal mine.Coal of medium cleanliness(grade IV)is distributed mainly in the regions of the Panji-Xiejiaji and Kouzidong coalmines.Relatively poor grade coal(grade V)is distributed in the southwest regions of the coalfield and the contents of Cr,As and Hg in coal collected from the relatively poor coal cleanliness regions often exceed the regulatory standards for the maximum concentration limits.展开更多
BACKGROUND The vaginal microbiome plays a critical role in the health of pregnant women and their newborns.Group B Streptococcus(GBS)and vaginal cleanliness significantly affect the vaginal microecosystem and are clos...BACKGROUND The vaginal microbiome plays a critical role in the health of pregnant women and their newborns.Group B Streptococcus(GBS)and vaginal cleanliness significantly affect the vaginal microecosystem and are closely associated with vaginal diseases.AIM To explore the effects of GBS status and vaginal cleanliness on vaginal microecosystems.METHODS We collected 160 vaginal swabs from pregnant women and divided them into the following four groups based on GBS status and vaginal cleanliness:GBS-positive+vaginal cleanliness I–II degree,GBS-negative+vaginal cleanliness I–II degree,GBS-positive+vaginal cleanliness III–IV degree,and GBS-negative+vaginal cleanliness III–IV degree.Samples were subjected to 16S rRNA gene amplicon sequencing.RESULTS Alpha diversity analysis showed that the Shannon index did not significantly differ between the four groups.We identified significant variation in taxa abundance between the GBS-positive and GBS-negative groups and between the vaginal cleanliness I–II degree and III–IV degree groups.Principal coordinate analysis and non-metric multidimensional scaling analysis further confirmed the microbial diversity of the four groups.Moreover,the linear discriminant analysis demonstrated that Lactobacillus jensenii and Actinobacteria were strongly associated with GBS-positive status,and Lactobacillus iners,Lactobacillaceae,Lactobacillus,Lactobacillales,Bacilli and Firmicutes were closely correlated with GBS-negative status.CONCLUSION GBS status and vaginal cleanliness significantly affect vaginal microbiome differences in pregnant women.Our findings provide instructional information for clinical antibiotic treatment in pregnant women with different GBS statuses and vaginal cleanliness degrees.展开更多
The effect of the axial static magnetic field(ASMF)on cleanliness and microstructure in magnetically controlled electroslag remelted GCr15 bearing steel ingots was investigated experimentally.The results show that a m...The effect of the axial static magnetic field(ASMF)on cleanliness and microstructure in magnetically controlled electroslag remelted GCr15 bearing steel ingots was investigated experimentally.The results show that a magnetically controlled spin-vibration induced by the interaction of the ASMFs and the remelting current exists at the consumable electrode tip,resulting in thinner liquid melt film and smaller droplets.With the increase in magnetic flux density,the optimization effect of ASMFs on electroslag remelting process increases and reaches the peak with a 40 mT ASMF,then decreases.The cleanliness of the ingots was improved,and the count of inclusions larger than 5μm was reduced.The microstructure of the ingots processed with a 40 mT ASMF was significantly refined.The depth of the metallic molten pool was reduced from 45.2 to 17.5 mm with the application of 40 mT ASMF.The tensile strength,impact toughness,and Rockwell hardness of the ingots obtained under the 40 mT ASMF were significantly improved.The mechanisms of the spin-vibration occurring at the electrode tip end were interpreted in detail to elucidate the effect of ASMFs.展开更多
The objective of maintaining the cleanliness of the multi-segment disk amplifier in Shenguang-II(SG-II) is to reduce laser-induced damage for optics. The flow field of clean gas, which is used for the transportation o...The objective of maintaining the cleanliness of the multi-segment disk amplifier in Shenguang-II(SG-II) is to reduce laser-induced damage for optics. The flow field of clean gas, which is used for the transportation of contaminant particles,is a key factor affecting the cleanliness level in the multi-segment disk amplifier. We developed a gas–solid coupling and three-dimensional flow numerical simulation model. The three-dimensional and two-phase flow model is verified by the flow-field smog experiment and the particle concentration measurement experiment with the 130-disk amplifier in SG-II. By optimizing the boundary conditions with the same flow rate, the multi-inlet vector flow scheme can not only effectively reduce the purging time, but also prevent the reverse diffusion of contaminant particles in the multi-segment disk amplifier and the deposition of contaminant particles on the surface of the Nd:glass.展开更多
As the key part for energy amplification of high-power laser systems,disk amplifiers must work in an extremely clean environment.Different from the traditional cleanliness control scheme of active intake and passive e...As the key part for energy amplification of high-power laser systems,disk amplifiers must work in an extremely clean environment.Different from the traditional cleanliness control scheme of active intake and passive exhaust(AIPE),a new method of active exhaust and passive intake(AEPI)is proposed in this paper.Combined with computational fluid dynamics(CFD)technology,through the optimization design of the sizes,shapes,and locations of different outlets and inlets,the turbulence that is unfavorable to cleanliness control is effectively avoided in the disk amplifier cavity during the process of AEPI.Finally,the cleanliness control of the cavity of the disk amplifier can be realized just by once exhaust.Meanwhile,the micro negative pressure environment in the amplifier cavity produced during the exhaust process reduces the requirement for sealing.This method is simple,time saving,gas saving,efficient,and safe.It is also suitable for the cleanliness control of similar amplifiers.展开更多
Shot-peened,case-hardened gears can fail in the tooth root due to crack initiation below the surface of the steel matrix.Here,the crack is initiated at a non-metallic inclusion in the center of a so-called fisheye.Thi...Shot-peened,case-hardened gears can fail in the tooth root due to crack initiation below the surface of the steel matrix.Here,the crack is initiated at a non-metallic inclusion in the center of a so-called fisheye.This failure type can lead to a reduced endurance fatigue limit of the gears.It is for this reason that,over the last decade,much effort has been invested by steel manufacturers to reduce the non-metallic inclusion content of gear steels so as to mitigate or even completely prevent such crack initiation.These ultra-clean gear steels were achieved by various measures in the steel production process.However,as a result,the remaining non-metallic inclusions are inhomogeneously distributed in the steel volume in terms of both size and location.However,due to the inhomogeneity of ultra-clean steels,the question arose if the values derived according to the standards are still representative of ultra-clean steel batches.The results show that the standards can still be applied,but more effort must be applied.To determine the degree of cleanliness,six microsections are currently evaluated according to steel test specification(SEP)1571,method K.It is shown that an examination of 24 microsections starting from size class 0 seems beneficial to get more reliable and comparable results of the degree of cleanliness of these ultra-clean gear steels.In addition,it is shown that a high degree of cleanliness has been achieved for all steel batches investigated with the measures taken in the steel production process.展开更多
The cleanliness and defects for cold-rolled steel sheet caused by inclusions are greatly influenced by parameters in the metallurgical processing. Good control of parameters during the processing can lead to a better ...The cleanliness and defects for cold-rolled steel sheet caused by inclusions are greatly influenced by parameters in the metallurgical processing. Good control of parameters during the processing can lead to a better product. In this paper, data mining was used to explore the influence of parameters on defects in steel sheets. A decision tree model was established and it was found that the oxygen content before deoxidation, the end-point temperature of the converter, and the temperature before deoxidation had a great impact on the defects in the cold-rolled sheet that were caused by inclusions. This finding was confirmed by experiments with infrared absorption, scanning electron microscopy(SEM), energy dispersive X-ray spectroscopy(EDS), and automatic inclusion analysis methods. After optimization according to results from the model and experiments, the defect rate caused by the inclusions was reduced from 0.92% to 0.38%.展开更多
Particulate matter(PM), one of the most important pollutants of traffic emission, threatens the health of urban ecosystems and citizens. Roadside trees play an important role in trapping PM, and the foliar PM load is ...Particulate matter(PM), one of the most important pollutants of traffic emission, threatens the health of urban ecosystems and citizens. Roadside trees play an important role in trapping PM, and the foliar PM load is a useful indicator for air PM pollution in road systems. To detect the relationships of foliar PM load with road structures, urbanization, and meteorology in road systems, we studied a widely-planted tree Sophora japonica L. in 100 roads and 10 yards of Beijing, China, and found that the foliar PM loads increased with the distances from the urban centre(DUC) linearly, while decreased with the road density. All-subsets regression analysis indicated that DUC, average monthly relative humidity, average monthly wind speed, and mean annual wind speed were the most important factors in predicting foliar PM load, rather than general situation of buildings and road cleanliness. The monthly relative humidity and monthly wind speed had a negative correlation to foliar PM, while the annual relative humidity and annual wind speed had a positive correlation to foliar PM. Suburban areas and these effective factors should be highlighted in PM control in Beijing.展开更多
AIM To evaluate the ability of PillCamColon2 to visualize colonic segments missed by incomplete optical colonoscopy(OC) and to assess the diagnostic yield.METHODS This prospective multicentre study included 81 patient...AIM To evaluate the ability of PillCamColon2 to visualize colonic segments missed by incomplete optical colonoscopy(OC) and to assess the diagnostic yield.METHODS This prospective multicentre study included 81 patients from nine centres who underwent second-generation colon capsule endoscopy(CCE) following incomplete OC performed by an experienced gastroenterologist(> 1000 colonoscopies). Patients with stenosis were excluded. According to patient preferences, CCE was performed the following day(protocol A) after staying on clear liquids and 0.75 L Moviprep in the morning or within 30 d after new split-dose Moviprep(protocol B). Boosts consisted of 0.75 L and 0.25 L Moviprep, and phospho-soda was given as a rescue if the capsule was not excreted after seven hours.RESULTS Seventy-four patients were analysed(51% of them in group A; 49% in group B). Bowel cleansing was adequate in 67% of cases, and CCE could visualize colonic segments missed by incomplete colonoscopy in 90% of patients under protocol A and 97% of patients under protocol B(P = 0.35, n.s.). Significant polyps including adenocarcinoma were detected in 24% of cases. Detection rates for all polyps and significant polyps per patient were similar in both protocols. Polyps were found predominantly in the right colon(86%) in segments that were not reached by OC. Extracolonic findings-such as reflux esophagitis, suspected Barrett esophagus, upper GI-bleeding, gastric polyps, gastric erosions and angiectasia-were detected in eight patients. Pill Cam Colon2 capsule was retained in the ileum of one patient(1.4%) without symptoms and removed during an uneventful resection for unknown Crohn's disease that was diagnosed as the cause of anemia, which was the indication for colonoscopy. CCE was well tolerated. One patient suffered from selflimiting vomiting after consuming the phospho-soda.CONCLUSION Second-generation CCE using a low-volume preparation is useful after incomplete OC, and it allows for the detection of additional relevant findings, but cleansing efficiency could be improved.展开更多
Advancement in vacuum technologies and vapor deposition processes during last decades has led to the introduction of many modern coatings on metal cutting tools. Even in such an advanced vacuum coating techniques, the...Advancement in vacuum technologies and vapor deposition processes during last decades has led to the introduction of many modern coatings on metal cutting tools. Even in such an advanced vacuum coating techniques, the failure is not due to the wear of the coating but rather due to the lack of coating adhesion to the substrate. In this work, the coating adhesion test results were performed which is based on the Rockwell indentation tests. This coating adhesion tests were performed as per VDI standards 3198, 1991 for d.c. magnetron sputter deposition of diamond like carbon multilayer coating (DLC / TiN/ Ti / Cu / Ni) on tool substrate. Multilayer coating was deposited on tool substrates at different sputtering parameters/conditions such as power density, partial pressure, substrate temperature and reactive gases. The coated multilayer films were characterized by experimental techniques such as X-ray diffractometer which measures the material deposited, micro Raman spectroscopy and TEM to check DLC, Rockwell indentation to examine adhesion strength, optical profilometer to measure thickness of coating. Ni increases the Cu adhesion on tool substrate. Cu accommodates the shear stress induced by the films / substrate and the mismatch in thermal expansion coefficient, while Ti and TiN promote better DLC bonding. As the target power was increased the adhesion strength, micro hardness and deposition rate were observed to improve. Increase in target power and substrate temperature enhances adhesion strength. Proper substrate preparation and sequence of cleaning processes are the crucial factors for the enhancement of adhesion strength. The sputter deposition conditions for the above mentioned multilayer coatings are identified in this work to get improved quality with particular reference to adhesion and surface finish.展开更多
The morphologies evolution of various types of inclusions in Ti-IF steel were observed by a special depth erosion method,and the formation and evolution process were discussed.The results showed that the main inclusio...The morphologies evolution of various types of inclusions in Ti-IF steel were observed by a special depth erosion method,and the formation and evolution process were discussed.The results showed that the main inclusions were FeO·xMnO before Al deoxidization and the ratio of integrated oxygen and free oxygen was in ranged of 0.3 to 0.4.In present study,the main effect factors on the morphologies of Al2O3 inclusions were [Al]/[O]Free（soluble aluminum divide free oxygen） and initial free oxygen;cluster Al2O3 was formed easily with high free oxygen([O]Free) and low[Al]/[O]（blew 3 in present study）.Otherwise,the dendritic Al2O3 was formed;coral-like Al2O3 was the mixture of the dendrite Al2O3 and spherical Al2O3.Some Al2O3·TiOx inclusions appeared because a high[Ti]concentration region existed around 70TiFe（containing 70 percent titanium） particles after 70TiFe addition.The maximum sizes of Al2O3 reached 800μm when 3 min aluminum was added;as the time past,the large size Al2O3 decreased significantly;the maximum size of Al2O3 was blew 100μm and 50μm in calming sample and tundish sample respectively.展开更多
10% of elderly patients are functionally dependents and they therefore need permanent assistance. Orodental alterations may evolve into a pathological state in elderly people, which is increasing in the recent decades...10% of elderly patients are functionally dependents and they therefore need permanent assistance. Orodental alterations may evolve into a pathological state in elderly people, which is increasing in the recent decades. The current study analysed institutionalized patients in the district of Bari (Southern Italy), who have been so far monitored. We assessed 125 elderly institutionalized patients. The assessment has been carried out by an assessment questionnaire aiming at evaluating the patient’s psychophysical health status, objective intraoral test and prosthetic rehabilitations. About 90% of enrolled patients reported a good general health status. The main dental problems are due to the complete lack of specific prevention and treatment programs, together with handicap, presence of systemic diseases and medicines taken. The level of oral hygiene is poor and the conditions of the residual dental elements are precarious because of root caries and periodontal problems. Prostheses are usually old (on average 15) and appear scarcely retentive and unstable. We believe in the need for specific interventions aiming at the various issues emerging from the present study, so as to achieve a smaller prevalence of dental loss, periodontal disease and caries. These relatively simple interventions are now lacking because of the non-demand of treatment from patients and for economical reasons.展开更多
This paper provides analytical diagnosis of mechanical conditions of medical waste incinerators used for healthcare waste (HCW) treatment in Tanzania. The main features assessed were types of incinerators, features of...This paper provides analytical diagnosis of mechanical conditions of medical waste incinerators used for healthcare waste (HCW) treatment in Tanzania. The main features assessed were types of incinerators, features of incinerators and incinerator house. The assessment was conducted in three levels of health care facilities (HCFs), that is, Regional, district hospitals and health centers, existed in 26 regions of Tanzania. Questionnaires, interview and checklists were used as tools for data collection. It was observed that High-Tech incinerators are mainly used in regional hospitals, while district hospital and health center use both High-Tech and De-Montfort incinerators. About 60% of the incinerators have defective doors. More than 55% of incinerators are corroded in regional and district hospitals. The chimney, top plates and grate which are good condition are 55.6% and 60% in regional hospitals and health centers, respectively. The situation is below 50% in district hospitals. The leakage of the roof and loose structures were observed in district hospitals and health center to be more than 50% of the incinerator houses. On other hand, the performance of burners and incinerator housing cleanliness are generally good. It was concluded that the incinerators in the HCFs are in bad conditions, necessitating maintenance.展开更多
The construction of gas and oil plants include many items such as steel structures, equipments, piping, tanks and vessels at different conditions such as offshore, onshore, above and underground shall be protected aga...The construction of gas and oil plants include many items such as steel structures, equipments, piping, tanks and vessels at different conditions such as offshore, onshore, above and underground shall be protected against corrosion by coating. The protective value of a coating system is proportional to the surface preparation;the objectives of the surface preparation are the surface cleanliness and the surface profile of the substrate. The surface preparation is usually achieved by blast cleaning using different types of abrasive. Due to its high hardness and low cost, silica sand has been used extensively for impact abrasion. It is, however, very brittle with most grain disintegrating on impact, causing excessive levels of siliceous dust which is a major health hazard and causes serious environmental pollution. Consequently, it has been banned as impact abrasive material in most countries around the world. Considerable research has been done in the last twenty years to find an impact abrasive material as hard as silica and that respects. So it was important to search for sand substitution among the local abundant minerals in Egypt. Waste product obtained from ilmenite ore extracted from the mine was found to be the most suitable alternative abrasive. This work shows the abrasive types, the occurrence of the ilmenite ore. The chemical properties, physical properties and microscopic examination of the waste were investigated. The obtained result indicates that, the waste product obtained from ilmenite ore can be utilized for abrasion as sand substitution.展开更多
Compost barns for dairy cows are showing increased popularity also in Central Europe. A compost barn is used mainly as a two-area system with a bedded lying area and a solid feeding alley. Sawdust or dry fine wood sha...Compost barns for dairy cows are showing increased popularity also in Central Europe. A compost barn is used mainly as a two-area system with a bedded lying area and a solid feeding alley. Sawdust or dry fine wood shavings or wood chips are mostly used as bedding material, which has to be stirred twice a day. Stirring aerates and mixes faeces and urine into the bedding material, the mixture decomposes by means of aerobic microorganisms. A joint research project between the Agricultural Research and Education Centre Raumberg-Gumpenstein (HBLFA) and the Institute for Sustainability Sciences Tänikon (ISS) analyzed amongst other things, the cleanliness of the animals, integument alterations, lying behaviour and the current lameness situation of animals. A total of 138 cows were examined on five Austrian dairy farms. All cows were visually scored and animal behaviour was observed by data loggers as well as by direct observation. The mean value concerning cleanliness of animals was 0.44, while the udder was the cleanest and the lower leg the dirtiest area. Only a few lesions in carpal and tarsal joints could be found. Cows showed no differences in lying behaviour between times of day and temperatures. Large differences in lying behaviour were evident among farms. While on the compost barn farms only around 25% of all cows were scored to be lame, on cubicle-housing system farms 31% - 46% of the cows fell into that category (p < 0.001). From the present results, the compost barn can be seen as an animal-friendly system. In further investigations other factors affecting animal health and to resolve any outstanding issues concerning economy and alternative litter materials should be analyzed.展开更多
Objective:To explore the impact of comprehensive nursing intervention on the quality of intestinal preparation in the process of intestinal preparation for hospitalized patients undergoing colonoscopy.Methods:A total ...Objective:To explore the impact of comprehensive nursing intervention on the quality of intestinal preparation in the process of intestinal preparation for hospitalized patients undergoing colonoscopy.Methods:A total of 320 patients underwent colonoscopy in our department from January to June 2021.They were grouped by random number table.There were 160 cases in the control group and 160 cases in the observation group.The adverse reactions of intestinal preparation and the cleanliness of intestinal preparation were analyzed.Results:Through comprehensive nursing intervention,it can be found that the incidence of adverse reactions in the preparation of colonoscopy in the control group was 24.38%,and that in the observation group was 13.48%.The results showed that the incidence of adverse reactions in the preparation of colonoscopy was significantly lower than that in the control group(P<0.05),which indicates that the difference was statistically significant.In the control group,105 people qualified in intestinal cleanliness score(>5 points)during enteroscopy preparation,and the cleanliness qualification rate was 65.63%.In the observation group,139 people qualified in intestinal cleanliness score(>5 points)during enteroscopy preparation,and the cleanliness qualification rate was 86.88%.The cleanliness qualification rate of enteroscopy preparation was significantly higher than that of the control group,and P<0.05,which indicates that the difference was statistically significant.Conclusion:Comprehensive nursing intervention can promote the quality of preparation of patients for colonoscopy,improve the compliance of patients and improve the accuracy of examination effect.展开更多
The microporous magnesia refractory shows a promising application prospect as tundish lining due to excellent thermal insulation and slag resistance.The effect of interaction between microporous magnesia castable and ...The microporous magnesia refractory shows a promising application prospect as tundish lining due to excellent thermal insulation and slag resistance.The effect of interaction between microporous magnesia castable and 38CrMoAl steel containing 0.876 wt.%Al on the cleanliness of 38CrMoAl steel was studied and compared with that of fused magnesia castable.The results show that the micropores in the microporous magnesia castable can promote the formation of dense and continuous MgO-Al_(2)O_(3)layer,which can inhibit the further pollution of molten steel by refractories,whereas the MgO-Al_(2)O_(3)layer formed in test of fused magnesia castable is not continuous.After 30 min holding,the total oxygen content in the steel samples for the test of microporous magnesia castable is only 42.2%of that for the test of fused magnesia castable.The inclusions in the steel samples for the test of microporous magnesia castable are also less than those for the test of fused magnesia castable.It shows that microporous magnesia castable is a promising tundish refractory for the preparation of clean high-Al steel.展开更多
基金financially supported by the National Natural Science Foundation of China (No.51404022)
文摘During the production of Ti-bearing Al-killed ultra-low-carbon(ULC) steel, two different heating processes were used when the converter tapping temperature or the molten steel temperature in the Ruhrstahl–Heraeus(RH) process was low: heating by Al addition during the RH decarburization process and final deoxidation at the end of the RH decarburization process(process-Ⅰ), and increasing the oxygen content at the end of RH decarburization, heating and final deoxidation by one-time Al addition(process-Ⅱ). Temperature increases of 10°C by different processes were studied; the results showed that the two heating processes could achieve the same heating effect. The T.[O] content in the slab and the refining process was better controlled by process-Ⅰ than by process-Ⅱ. Statistical analysis of inclusions showed that the numbers of inclusions in the slab obtained by process-Ⅰ were substantially less than those in the slab obtained by process-Ⅱ. For process-Ⅰ, the Al_2O_3 inclusions produced by Al added to induce heating were substantially removed at the end of decarburization. The amounts of inclusions were substantially greater for process-Ⅱ than for process-Ⅰ at different refining stages because of the higher dissolved oxygen concentration in process-Ⅱ. Industrial test results showed that process-Ⅰ was more beneficial for improving the cleanliness of molten steel.
文摘To make high integrity lightweight metal castings,best practices are required in various stages of casting and heat treatment processes,including liquid metal composition and quality control,casting and gating/riser system design,and process optimization.This paper presents best practices for liquid metal processing and quality assurance of molten metal in both melting and mold filling.Best practices for other aspects of lightweight metal casting will be published separately.
基金Project(2006BAJ02A10) supported by the National Key Technologies R&D Program
文摘A testing system for evaluating cleanliness of ventilation ducts was constructed. Comparisons of four evaluation methods for quantifying the amount of dust on the inner surface of ventilation ducts are presented. The experimental results show that the wiping by solvent method is more efficient than that by the wiping method,especially used on low cleanliness duct surface. The gravimetric tape method is an efficient method of collecting dust samples on the duct surface with low amounts of dust,particularly used to check the cleanliness level after the cleaning work. The optical method can be set up rapidly and is useful for fieldwork measurements.
基金the Key Research and Development Projects in Anhui Province(201904a07020071)the Science and Technology Project of the Department of Land and Resources of Anhui Province(2016-K-16)the Key Research and Development Projects in Anhui Province(1804a0802198).
文摘Based on analysis of a large data set and supplementary sampling and analysis for hazardous trace elements in coal samples from the Huainan Coalfield,a generalized contrast-weighted scale index method was used to establish a model to evaluate the grade of coal cleanliness and its regional distribution in the main coal seam(No.13-1)The results showed that:(1)The contents of Cr,Mn and Ni in the coal seam are relatively high and the average values are greater than 20μg/g.The contents of Se and Hg are at a high level while most other trace elements are at normal levels.(2)The cleanliness grade of the coal seam is mainly grade III-IV,which corresponds to a relatively good-medium coal cleanliness grade.However,some parts of the seam are at grade V(relatively poor coal cleanliness).(3)Coal of relatively good cleanliness grade(grade III)is distributed mainly in the regions corresponding to the Zhuji-Dingji-Gubei coal mines and in the eastern periphery of the Panji coal mine.Coal of medium cleanliness(grade IV)is distributed mainly in the regions of the Panji-Xiejiaji and Kouzidong coalmines.Relatively poor grade coal(grade V)is distributed in the southwest regions of the coalfield and the contents of Cr,As and Hg in coal collected from the relatively poor coal cleanliness regions often exceed the regulatory standards for the maximum concentration limits.
文摘BACKGROUND The vaginal microbiome plays a critical role in the health of pregnant women and their newborns.Group B Streptococcus(GBS)and vaginal cleanliness significantly affect the vaginal microecosystem and are closely associated with vaginal diseases.AIM To explore the effects of GBS status and vaginal cleanliness on vaginal microecosystems.METHODS We collected 160 vaginal swabs from pregnant women and divided them into the following four groups based on GBS status and vaginal cleanliness:GBS-positive+vaginal cleanliness I–II degree,GBS-negative+vaginal cleanliness I–II degree,GBS-positive+vaginal cleanliness III–IV degree,and GBS-negative+vaginal cleanliness III–IV degree.Samples were subjected to 16S rRNA gene amplicon sequencing.RESULTS Alpha diversity analysis showed that the Shannon index did not significantly differ between the four groups.We identified significant variation in taxa abundance between the GBS-positive and GBS-negative groups and between the vaginal cleanliness I–II degree and III–IV degree groups.Principal coordinate analysis and non-metric multidimensional scaling analysis further confirmed the microbial diversity of the four groups.Moreover,the linear discriminant analysis demonstrated that Lactobacillus jensenii and Actinobacteria were strongly associated with GBS-positive status,and Lactobacillus iners,Lactobacillaceae,Lactobacillus,Lactobacillales,Bacilli and Firmicutes were closely correlated with GBS-negative status.CONCLUSION GBS status and vaginal cleanliness significantly affect vaginal microbiome differences in pregnant women.Our findings provide instructional information for clinical antibiotic treatment in pregnant women with different GBS statuses and vaginal cleanliness degrees.
基金This work is supported by the National Key Research and Development Program of China under Grant numbers of 2016YFB0300401,2018YFF0109404,and 2016YFB0301401the National Natural Science Foundation of China under Grant numbers of U1860202,U1732276,50134010,51704193,51904184,and 52004156the Users with Excellence Program of Hefei Science Center CAS under Grant number of 2019HSC-UE010,and the Changjiang Scholar Program of Chinese Ministry of Education.
文摘The effect of the axial static magnetic field(ASMF)on cleanliness and microstructure in magnetically controlled electroslag remelted GCr15 bearing steel ingots was investigated experimentally.The results show that a magnetically controlled spin-vibration induced by the interaction of the ASMFs and the remelting current exists at the consumable electrode tip,resulting in thinner liquid melt film and smaller droplets.With the increase in magnetic flux density,the optimization effect of ASMFs on electroslag remelting process increases and reaches the peak with a 40 mT ASMF,then decreases.The cleanliness of the ingots was improved,and the count of inclusions larger than 5μm was reduced.The microstructure of the ingots processed with a 40 mT ASMF was significantly refined.The depth of the metallic molten pool was reduced from 45.2 to 17.5 mm with the application of 40 mT ASMF.The tensile strength,impact toughness,and Rockwell hardness of the ingots obtained under the 40 mT ASMF were significantly improved.The mechanisms of the spin-vibration occurring at the electrode tip end were interpreted in detail to elucidate the effect of ASMFs.
基金supported by the National Natural Science Foundation of China (Grant No. 61505228)
文摘The objective of maintaining the cleanliness of the multi-segment disk amplifier in Shenguang-II(SG-II) is to reduce laser-induced damage for optics. The flow field of clean gas, which is used for the transportation of contaminant particles,is a key factor affecting the cleanliness level in the multi-segment disk amplifier. We developed a gas–solid coupling and three-dimensional flow numerical simulation model. The three-dimensional and two-phase flow model is verified by the flow-field smog experiment and the particle concentration measurement experiment with the 130-disk amplifier in SG-II. By optimizing the boundary conditions with the same flow rate, the multi-inlet vector flow scheme can not only effectively reduce the purging time, but also prevent the reverse diffusion of contaminant particles in the multi-segment disk amplifier and the deposition of contaminant particles on the surface of the Nd:glass.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA25020101)。
文摘As the key part for energy amplification of high-power laser systems,disk amplifiers must work in an extremely clean environment.Different from the traditional cleanliness control scheme of active intake and passive exhaust(AIPE),a new method of active exhaust and passive intake(AEPI)is proposed in this paper.Combined with computational fluid dynamics(CFD)technology,through the optimization design of the sizes,shapes,and locations of different outlets and inlets,the turbulence that is unfavorable to cleanliness control is effectively avoided in the disk amplifier cavity during the process of AEPI.Finally,the cleanliness control of the cavity of the disk amplifier can be realized just by once exhaust.Meanwhile,the micro negative pressure environment in the amplifier cavity produced during the exhaust process reduces the requirement for sealing.This method is simple,time saving,gas saving,efficient,and safe.It is also suitable for the cleanliness control of similar amplifiers.
基金The underlying research work was funded in equal proportions by the“Arbeitsgemeinschaft industrieller Forschungsvereinigungen e.V.(AiF)”,the German Federal Ministry of Economics and Technology(BMWi,IGF no.16662 N)and the FVA.The results presented in this paper were taken from the FVA research project 293 III“Späte Zahnfußbrüche/Reinheitsgrad”.More detailed information on the influence of non-metallic inclusions is given in the final report.
文摘Shot-peened,case-hardened gears can fail in the tooth root due to crack initiation below the surface of the steel matrix.Here,the crack is initiated at a non-metallic inclusion in the center of a so-called fisheye.This failure type can lead to a reduced endurance fatigue limit of the gears.It is for this reason that,over the last decade,much effort has been invested by steel manufacturers to reduce the non-metallic inclusion content of gear steels so as to mitigate or even completely prevent such crack initiation.These ultra-clean gear steels were achieved by various measures in the steel production process.However,as a result,the remaining non-metallic inclusions are inhomogeneously distributed in the steel volume in terms of both size and location.However,due to the inhomogeneity of ultra-clean steels,the question arose if the values derived according to the standards are still representative of ultra-clean steel batches.The results show that the standards can still be applied,but more effort must be applied.To determine the degree of cleanliness,six microsections are currently evaluated according to steel test specification(SEP)1571,method K.It is shown that an examination of 24 microsections starting from size class 0 seems beneficial to get more reliable and comparable results of the degree of cleanliness of these ultra-clean gear steels.In addition,it is shown that a high degree of cleanliness has been achieved for all steel batches investigated with the measures taken in the steel production process.
基金financially supported by the National Natural Science Foundation of China (No. 51704203)
文摘The cleanliness and defects for cold-rolled steel sheet caused by inclusions are greatly influenced by parameters in the metallurgical processing. Good control of parameters during the processing can lead to a better product. In this paper, data mining was used to explore the influence of parameters on defects in steel sheets. A decision tree model was established and it was found that the oxygen content before deoxidation, the end-point temperature of the converter, and the temperature before deoxidation had a great impact on the defects in the cold-rolled sheet that were caused by inclusions. This finding was confirmed by experiments with infrared absorption, scanning electron microscopy(SEM), energy dispersive X-ray spectroscopy(EDS), and automatic inclusion analysis methods. After optimization according to results from the model and experiments, the defect rate caused by the inclusions was reduced from 0.92% to 0.38%.
基金Under the auspices of National Natural Science Foundation of China(No.41430638)Special Found for Beijing Common Construction Project for Beijing Laboratory of Urban and Rural Ecological Environment(No.PXM2015_014207_000014)Grants from the Beijing Municipal Education Commission(No.PXM2019_014207_000099)
文摘Particulate matter(PM), one of the most important pollutants of traffic emission, threatens the health of urban ecosystems and citizens. Roadside trees play an important role in trapping PM, and the foliar PM load is a useful indicator for air PM pollution in road systems. To detect the relationships of foliar PM load with road structures, urbanization, and meteorology in road systems, we studied a widely-planted tree Sophora japonica L. in 100 roads and 10 yards of Beijing, China, and found that the foliar PM loads increased with the distances from the urban centre(DUC) linearly, while decreased with the road density. All-subsets regression analysis indicated that DUC, average monthly relative humidity, average monthly wind speed, and mean annual wind speed were the most important factors in predicting foliar PM load, rather than general situation of buildings and road cleanliness. The monthly relative humidity and monthly wind speed had a negative correlation to foliar PM, while the annual relative humidity and annual wind speed had a positive correlation to foliar PM. Suburban areas and these effective factors should be highlighted in PM control in Beijing.
文摘AIM To evaluate the ability of PillCamColon2 to visualize colonic segments missed by incomplete optical colonoscopy(OC) and to assess the diagnostic yield.METHODS This prospective multicentre study included 81 patients from nine centres who underwent second-generation colon capsule endoscopy(CCE) following incomplete OC performed by an experienced gastroenterologist(> 1000 colonoscopies). Patients with stenosis were excluded. According to patient preferences, CCE was performed the following day(protocol A) after staying on clear liquids and 0.75 L Moviprep in the morning or within 30 d after new split-dose Moviprep(protocol B). Boosts consisted of 0.75 L and 0.25 L Moviprep, and phospho-soda was given as a rescue if the capsule was not excreted after seven hours.RESULTS Seventy-four patients were analysed(51% of them in group A; 49% in group B). Bowel cleansing was adequate in 67% of cases, and CCE could visualize colonic segments missed by incomplete colonoscopy in 90% of patients under protocol A and 97% of patients under protocol B(P = 0.35, n.s.). Significant polyps including adenocarcinoma were detected in 24% of cases. Detection rates for all polyps and significant polyps per patient were similar in both protocols. Polyps were found predominantly in the right colon(86%) in segments that were not reached by OC. Extracolonic findings-such as reflux esophagitis, suspected Barrett esophagus, upper GI-bleeding, gastric polyps, gastric erosions and angiectasia-were detected in eight patients. Pill Cam Colon2 capsule was retained in the ileum of one patient(1.4%) without symptoms and removed during an uneventful resection for unknown Crohn's disease that was diagnosed as the cause of anemia, which was the indication for colonoscopy. CCE was well tolerated. One patient suffered from selflimiting vomiting after consuming the phospho-soda.CONCLUSION Second-generation CCE using a low-volume preparation is useful after incomplete OC, and it allows for the detection of additional relevant findings, but cleansing efficiency could be improved.
文摘Advancement in vacuum technologies and vapor deposition processes during last decades has led to the introduction of many modern coatings on metal cutting tools. Even in such an advanced vacuum coating techniques, the failure is not due to the wear of the coating but rather due to the lack of coating adhesion to the substrate. In this work, the coating adhesion test results were performed which is based on the Rockwell indentation tests. This coating adhesion tests were performed as per VDI standards 3198, 1991 for d.c. magnetron sputter deposition of diamond like carbon multilayer coating (DLC / TiN/ Ti / Cu / Ni) on tool substrate. Multilayer coating was deposited on tool substrates at different sputtering parameters/conditions such as power density, partial pressure, substrate temperature and reactive gases. The coated multilayer films were characterized by experimental techniques such as X-ray diffractometer which measures the material deposited, micro Raman spectroscopy and TEM to check DLC, Rockwell indentation to examine adhesion strength, optical profilometer to measure thickness of coating. Ni increases the Cu adhesion on tool substrate. Cu accommodates the shear stress induced by the films / substrate and the mismatch in thermal expansion coefficient, while Ti and TiN promote better DLC bonding. As the target power was increased the adhesion strength, micro hardness and deposition rate were observed to improve. Increase in target power and substrate temperature enhances adhesion strength. Proper substrate preparation and sequence of cleaning processes are the crucial factors for the enhancement of adhesion strength. The sputter deposition conditions for the above mentioned multilayer coatings are identified in this work to get improved quality with particular reference to adhesion and surface finish.
文摘The morphologies evolution of various types of inclusions in Ti-IF steel were observed by a special depth erosion method,and the formation and evolution process were discussed.The results showed that the main inclusions were FeO·xMnO before Al deoxidization and the ratio of integrated oxygen and free oxygen was in ranged of 0.3 to 0.4.In present study,the main effect factors on the morphologies of Al2O3 inclusions were [Al]/[O]Free（soluble aluminum divide free oxygen） and initial free oxygen;cluster Al2O3 was formed easily with high free oxygen([O]Free) and low[Al]/[O]（blew 3 in present study）.Otherwise,the dendritic Al2O3 was formed;coral-like Al2O3 was the mixture of the dendrite Al2O3 and spherical Al2O3.Some Al2O3·TiOx inclusions appeared because a high[Ti]concentration region existed around 70TiFe（containing 70 percent titanium） particles after 70TiFe addition.The maximum sizes of Al2O3 reached 800μm when 3 min aluminum was added;as the time past,the large size Al2O3 decreased significantly;the maximum size of Al2O3 was blew 100μm and 50μm in calming sample and tundish sample respectively.
文摘10% of elderly patients are functionally dependents and they therefore need permanent assistance. Orodental alterations may evolve into a pathological state in elderly people, which is increasing in the recent decades. The current study analysed institutionalized patients in the district of Bari (Southern Italy), who have been so far monitored. We assessed 125 elderly institutionalized patients. The assessment has been carried out by an assessment questionnaire aiming at evaluating the patient’s psychophysical health status, objective intraoral test and prosthetic rehabilitations. About 90% of enrolled patients reported a good general health status. The main dental problems are due to the complete lack of specific prevention and treatment programs, together with handicap, presence of systemic diseases and medicines taken. The level of oral hygiene is poor and the conditions of the residual dental elements are precarious because of root caries and periodontal problems. Prostheses are usually old (on average 15) and appear scarcely retentive and unstable. We believe in the need for specific interventions aiming at the various issues emerging from the present study, so as to achieve a smaller prevalence of dental loss, periodontal disease and caries. These relatively simple interventions are now lacking because of the non-demand of treatment from patients and for economical reasons.
文摘This paper provides analytical diagnosis of mechanical conditions of medical waste incinerators used for healthcare waste (HCW) treatment in Tanzania. The main features assessed were types of incinerators, features of incinerators and incinerator house. The assessment was conducted in three levels of health care facilities (HCFs), that is, Regional, district hospitals and health centers, existed in 26 regions of Tanzania. Questionnaires, interview and checklists were used as tools for data collection. It was observed that High-Tech incinerators are mainly used in regional hospitals, while district hospital and health center use both High-Tech and De-Montfort incinerators. About 60% of the incinerators have defective doors. More than 55% of incinerators are corroded in regional and district hospitals. The chimney, top plates and grate which are good condition are 55.6% and 60% in regional hospitals and health centers, respectively. The situation is below 50% in district hospitals. The leakage of the roof and loose structures were observed in district hospitals and health center to be more than 50% of the incinerator houses. On other hand, the performance of burners and incinerator housing cleanliness are generally good. It was concluded that the incinerators in the HCFs are in bad conditions, necessitating maintenance.
文摘The construction of gas and oil plants include many items such as steel structures, equipments, piping, tanks and vessels at different conditions such as offshore, onshore, above and underground shall be protected against corrosion by coating. The protective value of a coating system is proportional to the surface preparation;the objectives of the surface preparation are the surface cleanliness and the surface profile of the substrate. The surface preparation is usually achieved by blast cleaning using different types of abrasive. Due to its high hardness and low cost, silica sand has been used extensively for impact abrasion. It is, however, very brittle with most grain disintegrating on impact, causing excessive levels of siliceous dust which is a major health hazard and causes serious environmental pollution. Consequently, it has been banned as impact abrasive material in most countries around the world. Considerable research has been done in the last twenty years to find an impact abrasive material as hard as silica and that respects. So it was important to search for sand substitution among the local abundant minerals in Egypt. Waste product obtained from ilmenite ore extracted from the mine was found to be the most suitable alternative abrasive. This work shows the abrasive types, the occurrence of the ilmenite ore. The chemical properties, physical properties and microscopic examination of the waste were investigated. The obtained result indicates that, the waste product obtained from ilmenite ore can be utilized for abrasion as sand substitution.
文摘Compost barns for dairy cows are showing increased popularity also in Central Europe. A compost barn is used mainly as a two-area system with a bedded lying area and a solid feeding alley. Sawdust or dry fine wood shavings or wood chips are mostly used as bedding material, which has to be stirred twice a day. Stirring aerates and mixes faeces and urine into the bedding material, the mixture decomposes by means of aerobic microorganisms. A joint research project between the Agricultural Research and Education Centre Raumberg-Gumpenstein (HBLFA) and the Institute for Sustainability Sciences Tänikon (ISS) analyzed amongst other things, the cleanliness of the animals, integument alterations, lying behaviour and the current lameness situation of animals. A total of 138 cows were examined on five Austrian dairy farms. All cows were visually scored and animal behaviour was observed by data loggers as well as by direct observation. The mean value concerning cleanliness of animals was 0.44, while the udder was the cleanest and the lower leg the dirtiest area. Only a few lesions in carpal and tarsal joints could be found. Cows showed no differences in lying behaviour between times of day and temperatures. Large differences in lying behaviour were evident among farms. While on the compost barn farms only around 25% of all cows were scored to be lame, on cubicle-housing system farms 31% - 46% of the cows fell into that category (p < 0.001). From the present results, the compost barn can be seen as an animal-friendly system. In further investigations other factors affecting animal health and to resolve any outstanding issues concerning economy and alternative litter materials should be analyzed.
文摘Objective:To explore the impact of comprehensive nursing intervention on the quality of intestinal preparation in the process of intestinal preparation for hospitalized patients undergoing colonoscopy.Methods:A total of 320 patients underwent colonoscopy in our department from January to June 2021.They were grouped by random number table.There were 160 cases in the control group and 160 cases in the observation group.The adverse reactions of intestinal preparation and the cleanliness of intestinal preparation were analyzed.Results:Through comprehensive nursing intervention,it can be found that the incidence of adverse reactions in the preparation of colonoscopy in the control group was 24.38%,and that in the observation group was 13.48%.The results showed that the incidence of adverse reactions in the preparation of colonoscopy was significantly lower than that in the control group(P<0.05),which indicates that the difference was statistically significant.In the control group,105 people qualified in intestinal cleanliness score(>5 points)during enteroscopy preparation,and the cleanliness qualification rate was 65.63%.In the observation group,139 people qualified in intestinal cleanliness score(>5 points)during enteroscopy preparation,and the cleanliness qualification rate was 86.88%.The cleanliness qualification rate of enteroscopy preparation was significantly higher than that of the control group,and P<0.05,which indicates that the difference was statistically significant.Conclusion:Comprehensive nursing intervention can promote the quality of preparation of patients for colonoscopy,improve the compliance of patients and improve the accuracy of examination effect.
基金The authors gratefully acknowledge the support from National Natural Science Foundation of China(No.U1860205).
文摘The microporous magnesia refractory shows a promising application prospect as tundish lining due to excellent thermal insulation and slag resistance.The effect of interaction between microporous magnesia castable and 38CrMoAl steel containing 0.876 wt.%Al on the cleanliness of 38CrMoAl steel was studied and compared with that of fused magnesia castable.The results show that the micropores in the microporous magnesia castable can promote the formation of dense and continuous MgO-Al_(2)O_(3)layer,which can inhibit the further pollution of molten steel by refractories,whereas the MgO-Al_(2)O_(3)layer formed in test of fused magnesia castable is not continuous.After 30 min holding,the total oxygen content in the steel samples for the test of microporous magnesia castable is only 42.2%of that for the test of fused magnesia castable.The inclusions in the steel samples for the test of microporous magnesia castable are also less than those for the test of fused magnesia castable.It shows that microporous magnesia castable is a promising tundish refractory for the preparation of clean high-Al steel.
