Effect of titanium on the sticking of pellets based on hydrogen metallurgy shaft furnace:Behavior analysis and mechanism evolution

Direct reduction based on hydrogen metallurgical gas-based shaft furnace is a promising technology for the efficient and low-carbon smelting of vanadium-titanium magnetite.However,in this process,the sticking of pellets occurs due to the aggregation of metal-lic iron between the contact surfaces of adjacent pellets and has a serious negative effect on the continuous operation.This paper presents a detailed experimental study of the effect of TiO2 on the sticking behavior of pellets during direct reduction under different conditions.Results showed that the sticking index(SI)decreased linearly with the increasing TiO2 addition.This phenomenon can be attributed to the increase in unreduced FeTiO3 during reduction,leading to a decrease in the number and strength of metallic iron interconnections at the sticking interface.When the TiO2 addition amount was raised from 0 to 15wt%at 1100°C,the SI also increased from 0.71%to 59.91%.The connection of the slag phase could be attributed to the sticking at a low reduction temperature,corresponding to the low sticking strength.Moreover,the interconnection of metallic iron became the dominant factor,and the SI increased sharply with the increase in re-duction temperature.TiO2 had a greater effect on SI at a high reduction temperature than at a low reduction temperature.

Test research on sticking mechanism during hot rolling of SUS 430 ferritic stainless steel

The sticking phenomenon during hot rolling of SUS 430 ferritic stainless steel was investigated by means of a two-disc type high-temperature wear tester. The test results indicate that sticking particles on the surfaces of high chromium steel （HiCr） and high-speed steel （HSS） rolls undergo nucleation, growth, and saturation stages. Grooves on the roll surface generated by grinding provide nucleation sites for sticking particles. The number of sticking particles on the HiCr roll surface is greater than that on the HSS roll surface. The average surface roughnesses （Ra） of HiCr and HSS rolls change from 0.502 and 0.493 μm at the initial stage to 0.837 and 0.530 μm at the saturation stage, respectively. The test further proves that the sticking behavior is strongly dependent on roll materials, and the HSS roll is more benefi- cial to prevent particles sticking compared with the HiCr roll under the same hot-rolling conditions.

Wall Sticking of High Water-Cut, Highly Viscous and High Gel-Point Crude Oil Transported at Low Temperatures

Some crude oils with high water cut have the capability to flow below the oil gel point, while the oil particles adhere to the pipe wall in the form of paste, also called "wall sticking". Wall sticking is a serious problem during the pipeline transportation, leading to partial or total blockage of the pipeline and energy wastage. In this paper, a series of laboratory flow loop experiments were conducted to observe the wall sticking characteristics of crude oil with high water cut, high viscosity and high gel point at low transportation temperatures. The effects of shear stress and water cut on the wall sticking rate and occurrence temperature were investigated. Experimental results indicated that the wall sticking rate and occurrence temperature were lower under stronger shear stress and higher water cut conditions. A criterion of wall sticking occurrence temperature(WSOT) and a regression model of wall sticking rate were then established. Finally, the software was developed to calculate the pressure drop along the pipelines of crude oils with high water-cut. It was able to predict the wall sticking thickness of gelled oil and then calculate the pressure drop along the pipelines. A typical case study indicated that the prediction results obtained from the software were in agreement with actual measured values.

Prevalence of Occupational Injury and Knowledge of Post-Exposure Prophylaxis Accessibility among Healthcare Workers in Mogadishu, Somalia

Introduction: Healthcare workers in Mogadishu, Somalia face significant occupational injury risks, particularly needle stick injuries, with 61.1% reporting incidents. This poses a serious threat to their health, leading to infections such as hepatitis B, hepatitis C, and HIV. Despite the high prevalence of injuries, awareness of Post-Exposure Prophylaxis (PEP) accessibility is relatively high, with 84.0% of respondents aware of it. However, there are gaps in knowledge and implementation, as evidenced by variations in availability of PEP. Improving workplace safety measures, providing comprehensive training on injury prevention and PEP protocols, and ensuring consistent availability of PEP in healthcare facilities are crucial steps to safeguard the well-being of healthcare workers in Mogadishu, Somalia. Methods: A cross-sectional study was conducted among hospital workers in Mogadishu, Somalia, focusing on professionals from various healthcare facilities. The study targeted nurses, doctors, laboratory personnel, and pharmacists. Purposive sampling was employed, resulting in a sample size of 383 calculated using Fisher’s sample size formula. Data were collected using coded questionnaires entered into Microsoft Excel 2019 and analyzed with SPSS software to generate frequencies and proportions, presented through frequency tables and pie figures. Results: The study in Mogadishu, Somalia, examined the prevalence of occupational injuries and knowledge of Post-Exposure Prophylaxis (PEP) accessibility among healthcare workers. Findings indicate a high prevalence of injuries, with 61.1% reporting incidents, predominantly needle stick injuries (60.6%). Despite the majority seeking prompt medical attention (72.0%), work-related illnesses affected 53.2% of respondents, notably work-related stress (59.5%). While most received training on injury and illness prevention (68.9%), gaps exist in PEP awareness, with 16.0% unaware of it. Nonetheless, 84.0% were aware, predominantly through health facilities (52.0%). Availability of PEP was reported by 71.3% in healthcare facilities, with variations in shift availability. The majority reported guidelines for PEP use (55.7%). Efforts are needed to bolster PEP awareness and ensure consistent availability in healthcare facilities to safeguard worker health. Conclusion: High prevalence of occupational injuries among healthcare workers, with needle stick injuries being the most common (60.6%). Despite this, 84.0% of respondents were aware of Post-Exposure Prophylaxis (PEP), primarily learning about it from health facilities (52.0%). While 71.3% reported the availability of PEP in their facility, 28.7% noted its unavailability. These results emphasize the need for improved education and accessibility of PEP to mitigate occupational injury risks.

Characteristics of Water Absorption and the Loss of Dust-Sticking Agent

The development of NCZ-1 dust-sticking agent was first intreduced in china. The speed of water absorption of dust-stick-ing agent was measured and studied on mining site and in laboratory, and then the law of water absorption of dust-sticking agent was analyzed. In addition, the mathematical model of the loss rate of dust-sticking agent was established by the application of fluid mechanics theory, and the method of determining the sprinkle parameters of dust-sticking agent was obtained. Through practical verifi-cation, it is found that the error of this mathematical model is less than 10%. So it can be used in the field.

Hepatitis B Vaccination in Medical and Dental Students: A Cross-Sectional Study

Background: Medical and dental students are at risk of Hepatitis B Virus (HBV) infection. The study aimed to assess the vaccination status against Hepatitis B Virus of students in clinical and non-clinical years of a private medical and dental college, and their knowledge, attitude, and awareness about the subject. Methods: A cross-sectional study was conducted using a pretested, self-administered questionnaire among 203 medical and dental students of CMH Lahore Medical College and Institute of Dentistry (CMH LMC & IOD) in Lahore, Pakistan. Participants were evaluated for their knowledge and vaccination status against Hepatitis B Virus. Students were considered to be fully vaccinated (recipients of 3 doses), partially vaccinated (recipients of 1 or 2 doses), and unvaccinated. Comparisons were made between students of clinical and non-clinical years. Data was entered and analysed using Statistical Package for the Social Sciences (SPSS) version 23. Results: Only 66% (n = 134) of the 203 participants had ever received a Hepatitis B Virus vaccine out of which a meagre 17.2% (n = 35) were fully vaccinated. No significant difference was found in vaccine uptake between students of clinical and non-clinical years (p-value = 0.181) despite significant differences seen in the knowledge of vaccination schedule (p-value = 0.001), the prevalence of needle-stick injuries (p-value = 0.001), and knowledge of protocols to be followed after a needle-stick injury (p-value = 0.001). Conclusion: Our study found that a large proportion of the student population is vulnerable to HBV infection. There is a need to create awareness regarding the subject to increase vaccine uptake. HBV vaccination should be offered to all currently enrolled students and be made mandatory at the time of admission in the future.

STUDY ON SLAG DETACHABILITY AND STICK SLAG MECHANISM OF SSFCE

In the paper, the effects of linear expansion coefficient and basic index of melting slag on the detachability of self shielded flux cored electrode (SSFCE) are investigated. An equation is obtained on the principles of ceramics and mineralography which predict the detachability of basic SSFCE. In addition, stick slag mechanism of SSFCE is analyzed.

Effects of Plant Spacing and Finger Sticking Area Settings for Machine Transplanting on Yield of Double-season Early Rice

The effects of rice transplanters＇ transplanting settings（plant spacing and finger sticking area） on rice yield were investigated in two early-season rice cultivars：hybrid rice cultivar（Zhuliangyou 819） and conventional rice cultivar（Zhongjiazao 17）.The results showed that,different transplanting settings resulted in different numbers of transplanted basic seedlings,and the rice yield was significantly correlated with the number of transplanted basic seedlings.The number of transplanted basic seedlings increased with the decrease of plant spacing and the increase of finger sticking area.The rate of lost hills of machine transplanting decreased with the increase of finger sticking area.The leaf area index and amount of dry matter accumulation were highly correlated with the number of transplanted basic seedlings.The average yield of the rice transplanted with a plant spacing of11.5 cm was higher than that with a plant spacing of 13.8 cm.In the field transplanted with the rice under the plant spacing of 13.8 cm,the rice yield increased with the increase of finger sticking area,and the finger sticking area of 2.23 cm2 showed the highest rice yield of 8 174.16 kg/hm2 of Zhuliangyou 819 and 7 925.54kg/hm2 of Zhongjiaozao17.In the field transplanted with the rice under the plant spacing of 11.5 cm,the rice yield was the highest with the finger sticking area of 1.83 cm2,and then decreased with the large finger sticking area.Under the plant spacing of 11.5 cm,the highest rice yields of Zhuliangyou 819 and Zhongjiaozao17 were 8 492.94 kg/hm2 and 8 000.23 kg/hm2,respectively.Therefore,the preferred machine transplanting settings for double-season early rice are a plant spacing of11.5 cm and a finger sticking area of 1.83 cm2,while the finger sticking area should be increased to 2.23 cm2 for conventional rice cultivars.

抗癌膏穴位贴敷对Lewis肺癌模型小鼠癌细胞周期移行的影响

目的:探索抗癌膏穴位贴敷治疗癌症的作用机制。方法:用C57BL/6近交系小鼠,瘤细胞悬液皮下接种法造模,造模5日后用抗癌膏贴敷接种部位及“肺俞”穴,隔日治疗1次,治疗7次后,用流式细胞技术进行癌细胞周期分析。结果:抗癌膏使G1期细胞比例显著增加（P<0.05）,S期细胞比例显著减少（P<0.01）,细胞增殖指数显著下降（P<0.05）,癌细胞周期移行在G1期到S期之间发生阻滞。结论:抗癌膏通过抑制癌细胞增殖起到抗癌作用。

APPLICATION OF 2-D MOIRE INTERFEROMETRYOF STICKING FILM IN HUMAN TIBIA MEASUREMENT

This paper makes use of the method of testing and measuring the human body tibia by using2-D moire interferometry of sticking film. hased on the J'--y direction moire patterns recorded synchronously by 2-D optical path,the elastic constant,strain and displacement of the tibia are measured.Compared with the electric measuring method the error is samll and the sensitivity is high.

基于WebGIS的智能手机远程监控系统的设计与实现

提出了一套基于WebGIS的智能手机远程监控系统,介绍了系统的总体结构与设计思路。分析发生无线通信粘包现象的原因及后果并提出了解决方法;针对以往基于Web的实时监控系统的实时性不足,利用GPS信息及Ajax技术,实现了Web页面中的数据实时动态更新。

Comparison and analysis of two Coulomb friction models on the dynamic behavior of slider-crank mechanism with a revolute clearance joint

The objective of this study is to investigate the effects of the Coulomb dry friction model versus the modified Coulomb friction model on the dynamic behavior of the slider-crank mechanism with a revolute clearance joint. The normal and tangential forces acting on the contact points between the journal and the bearing are described by using a Hertzian-based contact force model and the Coulomb friction models, respectively.The dynamic equations of the mechanism are derived based on the Lagrange equations of the first kind and the Baumgarte stabilization method. The frictional force is solved via the linear complementarity problem(LCP) algorithm and the trial-and-error algorithm.Finally, three numerical examples are given to show the influence of the two Coulomb friction models on the dynamic behavior of the mechanism. Numerical results show that due to the stick friction, the slider-crank mechanism may exhibit stick-slip motion and can balance at some special positions, while the mechanism with ideal joints cannot.

Sticking of iron ore pellets in direct reduction with hydrogen and carbon monoxide:Behavior and prevention

A series of reduction experiments of iron ore pellets with hydrogen,carbon monoxide and their mixture were carried out in a laboratory scale shaft furnace.The sticking behavior accompanying reduction of iron ore pellets was investigated.And morphology of the sticking interface forming during reduction was analyzed by SEM equipped with EDS.In order to evaluate the effects of the temperature and gas composition on sticking properties,reduction of iron ore pellets were conducted at 800-1000 ℃.The results show that the sticking strength of the pellets increases with temperature,however,decreases with hydrogen content in reducing gas.For an efficient shaft furnace operation in direct reduction(DR),relative prevention of sticking such as coating of pellets was also developed to solve sticking problem.The results show that CaO is a suitable material for the coating method.

A New Method for Predicting Wall Sticking Occurrence Temperature of High Water Cut Crude Oil

In crude oil transportation, adhesion of oil on pipe wall can cause partial or total blockage of the pipe. This process is significantly affected by wall sticking occurrence temperature(WSOT). In this work, an efficient approach for estimating WSOT of high water-cut oil, which can agree well with the actual environment of multiphase transportation pipeline, is proposed. Based on the energy dissipation theory, it is possible to make comparison of average shear rates between the stirred vessel and the flow loop. The impacts of water content and shear rate on WSOT are investigated using the stirred vessel and the flow loop. Good agreement has been observed between the stirred vessel and the flow loop results with the maximum and the average absolute deviations equating to 3.30 °C and 2.18 °C, respectively. The development of gathering scheme can enjoy some benefits from this method.

Mechanism of die soldering during aluminum die casting

Soldering is a unique casting defect associated with die casting or metal mold casting of aluminum al oys. It occurs when molten aluminum sticks or solders the surface of the die steel and remains there after the ejection of the casting, causing a surface defect and dimensional inaccuracy of the castings and increased machine downtime. Soldering occurs easily when a bare die steel mold is used for die casting of aluminum al oys. When molten aluminum comes in contact with the die steel at a temperature higher than a critical temperature, the iron and aluminum atoms diffuse into each other, forming a series of intermetallic phases and a liquid aluminum-rich fcc phase. This liquid phase exists between intermetal ic phases. On cooling, the liquid fcc phase solidiifes on the intermetal ic phases and grows into the casting, resulting in soldering. The critical temperature is the eutectic temperature near the aluminum corner of the phase diagram. If the die is protected using a nonreactive ceramic coating, soldering starts at locations where local coating failure occurs. Molten aluminum comes into contact with die steel through the coating failure locations and eats into the steel matrix, forming smal pits. As these smal pits grow, the coating is gradual y removed and soldering becomes more severe. Details of die soldering step on a bare steel die and on a coated die material are discussed.

Modeling and simulation of solvent behavior and temperature distribution within long stick propellants with large web thickness undergoing drying

Drying is a complicated physical process which involves simultaneous heat and mass transfer in the removal of solvents inside propellants.Inappropriate drying techniques may result in the formation of a hard skin layer near the surface to block the free access of most solvent through for long stick propellants with large web thickness,which lead to lower drying efficiency and worse drying quality.This study aims to gain a comprehensive understanding of drying process and clarify the mechanism of the blocked layer near the propellant surface.A new three-dimensional coupled heat and mass transfer(3D-CHMT)model was successfully developed under transient conditions.The drying experiment results show that the 3DCHMT model could be applied to describe the drying process well since the relative error of the content of solvent between simulation and experiment values is only 5.5%.The solvent behavior simulation demonstrates that the mass transfer process can be divided into super-fast(SF)and subsequent minorfast(MF)stages,and the SF stage is vital to the prevention of the blocked layer against the free access for solvent molecules inside propellant grains.The effective solvent diffusion coefficient(Deff)of the propellant surface initially increases from 3.4×10^(-6)to 5.3×10^(-6)m^(2)/s as the temperature increases,and then decreases to 4.1×10^(-8)m^(2)/s at 60-100 min.The value of Deffof surface between 0-1.4 mm has a unique trend of change compared with other regions,and it is much lower than that of the internal at100 min under simulation conditions.Meanwhile,the temperature of the propellant surface increases rapidly at the SF stage(0-100 min)and then very slowly thereafter.Both the evolution of Deffand temperature distribution demonstrate that the blocked layer near the propellant surface has been formed in the time period of approximately 0-100 min and its thickness is about 1.4 mm.To mitigate the formation of blocked layer and improve its drying quality of finial propellant products effectively,it should be initially dried at lower drying temperature(30-40℃)in 0-100 min and then dried at higher drying temperature(50-60℃)to reduce drying time for later drying process in double base gun propellants.The present results can provide theoretical guidance for drying process and optimization of drying parameters for long stick propellants with large web thickness.

Value of a new stick-type rapid urine test for the diagnosis of Helicobacter pylori infection in the Vietnamese population

AIM: To assess the value of a new test for the diagnosis of Helicobacter pylori (H. pylori) infection, Rapirun®H. pylori Antibody Stick (Rapirun® Stick), in a Vietnamese population.

基于VISIO辅助绘制光纤通信设备开通图

针对传统图表制作工具存在的不足,介绍了VISIO的主要特点和光纤通信设备开通图辅助生成的过程,重点描述了台站、设备的排列规则和设备连接规则,实现了主要算法,对深化VISIO在通信领域中的应用做了有益的探索。

Charactering the spoilage mechanism of"three sticks"of Jinhua ham

To investigate the spoilage characteristics of Jinhua ham,sensory scores,volatile compounds,biogenic amine,physicochemical parameters and microbial counts were evaluated between normal and spoiled hams.The results showed that off-odors of spoiled hams were dominated by rancid,sour,sulfide and ammonia odors derived from these compounds including butanoic acid,methanethiol and dimethyl disulfide.Total content of biogenic amine in spoiled hams was significantly higher(more than 10-fold)compared with normal hams,and putrescine,cadaverine and histamine were the key components of biogenic amine of spoiled hams.Lower salt content,and higher moisture,TVB-N and thiobarbituric acid reactive substances(TBARS)values were observed in spoiled hams compared with normal hams.The populations of Enterobacteriaceae and Enterococcus of spoiled hams were obviously higher than that of normal hams.High moisture and low salt content caused the abnormal growth of Enterobacteriaceae and Enterococcus in spoiled hams,which contributed to the spoilage of Jinhua ham.

Influence of Oil and Water Components on Wall-sticking Occurrence Temperature in High Water-cut Crude Oil Pipeline

To study the wall-sticking phenomenon and prevent pipeline blockage accidents,two analytical methods are used to evaluate the influence of different crude oil components on the wall-sticking occurrence temperature(WSOT).The WSOT and the interactions among oil,water,and surface solids are measured and calculated by various devices under different values of the wax content,water pH,and salinity.The results show that there is greater correlation between the wax content and WSOT than between resins/asphaltenes and WSOT.Furthermore,the wax content,water pH,and salinity have different effects on WSOT.There is generally a positive correlation between wax content and WSOT,whereas the maximum WSOT occurs when the water pH is in the range 5.7–6.5,and decreases under more acidic or alkaline conditions.As the salinity increases,WSOT decreases slightly,but quickly becomes saturated.In terms of interactions,variations in the interfacial tension and adhesion work with pH and salinity are consistent with that of WSOT,while the contact angle exhibits the opposite relation.