Introduction: In Burkina Faso, undernutrition is a public health problem associated with more than 40% of infant and child mortality. Undernutrition management is complex, and there is often a risk of treatment abando...Introduction: In Burkina Faso, undernutrition is a public health problem associated with more than 40% of infant and child mortality. Undernutrition management is complex, and there is often a risk of treatment abandonment. Studies on this topic have not explored the influence of environmental and therapeutic factors on parental compliance. This study proposes an analysis of factors influencing the abandonment of nutritional recovery by parents of malnourished children aged 6 to 59 months in ambulatory care. Methods: This was a descriptive and exploratory qualitative study. Data collection took place in February 2020. Data were collected from seventeen (17) participants via in-depth interviews (IDI) and direct observation. The IDIs were transcribed verbatim and thematically analyzed using Nvivo software. Results: The results revealed that factors related to the physical environment, such as geographical inaccessibility, pastoral occupation, displacement at auriferous sites, and insecurity, are important causes of nutritional recovery abandonment. They also prove that factors related to the social environment, such as lack of family and social support, feelings of shame, stigmatization, occupation of the mother, and social events, lead to this abandonment. In addition, therapeutic factors such as interruptions of supplies of Ready to Use Therapeutic Food (RUTF), feeling of improvement or worsening of the state of health, recourse to traditional medicine, and ignorance of undernutrition are also associated with this issue. Conclusion: This study highlighted barriers to the abandonment of nutritional recovery among parents of severely malnourished children aged 6 to 59 months in the health district of Titao, Burkina Faso. It is more important to consider these different factors when evaluating care protocols so that policies to reduce child undernutrition can considerably impact the targets.展开更多
The implementation of WHO guidelines has significantly reduced hospital mortality due to severe malnutrition. Nevertheless, severe acute malnutrition in children under five remains a major public health problem in all...The implementation of WHO guidelines has significantly reduced hospital mortality due to severe malnutrition. Nevertheless, severe acute malnutrition in children under five remains a major public health problem in all low-income countries and is little studied. The study aimed to assess the nutritional status and quality of management of severe acute malnutrition in children aged 06 to 59 months hospitalized in the pediatric ward of Kayanza Hospital. This is a prospective study with descriptive and analytical aims over 6 months from February 10 to July 9, 2023. All children aged 6 to 59 months admitted for severe acute malnutrition are included in this study. The results show that the most affected age group is 12 to 23 months (42.55%). Marasmus is the most common clinical form, at 70.2%. Housewives and mothers from rural areas are the most affected, with rates ranging from 69.14% to 91.49%. The study shows that the reasons for consultation are respectively: edema (29.78%), diarrhea (26.59%), vomiting (19.14%), and fever (14.89%). Dehydration and hypothermia were the main complications observed in 45.74% and 22.34% respectively. Medical treatment was provided by antibiotics (44.68%), artesunate (31.91%), and resomal (21.27%). Nutritional treatment consisted of F75 100% milk and F100 100% milk. Pathologies observed were: anemia 38.29%, malaria 37.23%, urinary tract infection 12.7%, measles 11.7%. The national protocol for integrated management of acute malnutrition (PCIMA) was followed. This study shows that 72.3% of children were successfully treated, with 9.5% dropping out and dying, and 8.5% not responding. We found that malnutrition remains a public health problem, affecting mostly children aged 12 to 24 months. The main complications or pathologies associated with malnutrition are diarrhea, malaria, and fever, and the majority of children suffer from marasmus.展开更多
In this study, three rapid repair techniques are proposed to retrofit circular bridge piers that are severely damaged by the flexural failure mode in major earthquakes. The quasi-static tests on three 1：2.5 scaled ci...In this study, three rapid repair techniques are proposed to retrofit circular bridge piers that are severely damaged by the flexural failure mode in major earthquakes. The quasi-static tests on three 1：2.5 scaled circular pier specimens are conducted to evaluate the efficiency of the proposed repair techniques. For the purpose of rapid repair, the repair procedure for all the specimens is conducted within four days, and the behavior of the repaired specimens is evaluated and compared with the original ones. A finite element model is developed to predict the cyclic behavior of the repaired specimens and the numerical results are compared with the test data. It is found that all the repaired specimens exhibit similar or larger lateral strength and deformation capacity than the original ones. The initial lateral stiffness of all the repaired specimens is lower than that of the original ones, while they show a higher lateral stiffness at the later stage of the test. No noticeable difference is observed for the energy dissipation capacity between the original and repaired pier specimens. It is suggested that the repair technique using the early-strength concrete jacket confined by carbon fiber reinforced polymer （CFRP） sheets can be an optimal method for the rapid repair of severely earthquake-damaged circular bridge piers with flexural failure mode.展开更多
AIM: To evaluate the efficacy of surgical treatment of vitrectomy combined with silicone oil tamponade in the treatment of severely traumatized eyes with the visual acuity of no light perception (NLP).METHODS: This wa...AIM: To evaluate the efficacy of surgical treatment of vitrectomy combined with silicone oil tamponade in the treatment of severely traumatized eyes with the visual acuity of no light perception (NLP).METHODS: This was a retrospective uncontrolled interventional case-series of 19 patients of severely traumatized eyes with NLP who underwent vitrectomy surgery at the Affiliated Hospital of Medical College, Qingdao University (Qingdao, China) during a 3-year period. We recorded perioperative factors with the potential to influence functional outcome including duration from the injury to intervention; causes for ocular trauma; open globe or closed globe injury; grade of vitreous hemorrhage; grade of endophthalmitis; grade of retinal detachment; size and location of intraocular foreign body (IOFB); extent and position of retinal defect; grade of proliferative vitreoretinopathy (PVR); type of surgery; perioperative complications and tamponade agent. The follow-up time was from 3 to 18 months, and the mean time was 12 months.RESULTS: After a mean follow-up period of 12 months (3-18 months) 10.53% (2/19) of eyes had visual acuity of between 20/60 and 20/400, 52.63% (10/19) had visual acuity less than 20/400 but more than NLP, and 36.84% (7/19) remained NLP. Visual acuity was improved from NLP to light perception (LP) or better in 63.16% (12/19) of eyes and the rate of complete retinal reattachment was 73.68% (14/19). Good visual acuity all resulted from those patients of blunt trauma with intact eyewall (closed globe injury). The perioperative factors of poor visual acuity prognosis included delayed intervention; open globe injury; endophthalmitis; severe retinal detachment; large IOFB; macular defect; a wide range of retinal defects andsevere PVR.CONCLUSION: The main reasons of NLP after ocular trauma are severe vitreous hemorrhage opacity; refractive media opacity; retinal detachment; retinal and uveal damages and defects, especially defects of the macula; PVR and endophthalmitis. NLP after ocular trauma in some cases does not mean permanent vision loss. Early intervention of vitrectomy combined with silicone oil tamponade and achieving retinal reattachment of the remaining retina, may make the severely traumatized eyes regain the VA of LP or better.展开更多
The stabilization of severely As-polluted soil has been a challenge, especially for the extremely toxic As(Ⅲ) contaminants. In this study, soil with a high As concentration(26084 mg/kg) was availably stabilized by a ...The stabilization of severely As-polluted soil has been a challenge, especially for the extremely toxic As(Ⅲ) contaminants. In this study, soil with a high As concentration(26084 mg/kg) was availably stabilized by a H2O2 pre-oxidation assisted TMT-15(Na3S3C3N3 solution with a mass fraction of 15%) and FeCl3·6 H2O stabilization method. The results showed that the combination of the two stabilizers(i.e., TMT-15 and FeCl3·6 H2O) presented a better stabilization behavior than either stabilizer used individually. The use of the H2O2 pre-oxidation assisted TMT-15 and FeCl3·6 H2O stabilization approach not only converted the As(Ⅲ) to As(Ⅴ) but also reduced the toxic leaching concentration of As to 1.61 mg/L, which is a safe level, when the additions of TMT-15 and FeCl3·6 H2O were 2 mL and 0.20 g, respectively. Thus, using only a simple H2O2 pre-oxidation to combine clean stabilization with non-toxic stabilizers TMT-15 and FeCl3·6 H2O could render the severely As-contaminated soil safe for disposal in a landfill.展开更多
Historically,frequent and heavy snow disaster(SD)has caused serious livestock death and casualties,resulting in a devastating impact on animal husbandry development in the Three Rivers Source Region(TRSR).From winter ...Historically,frequent and heavy snow disaster(SD)has caused serious livestock death and casualties,resulting in a devastating impact on animal husbandry development in the Three Rivers Source Region(TRSR).From winter in 2018 to spring in 2019,the largest SD occurred in this area over the past 10 years,especially in core zones of the Lancang River Source Region.Field research results show that the main causes of the major SD include weak infrastructure(i.e.,roads,communications,warm sheds,and insufficient forage reserve),low rate of domestic animals for sale before the SD,and low loss settlement rate.SD occurrence could furtherly reduce the ability of disaster prevention,mitigation and relief of disaster loss.In the future,heavily affected SD areas should improve the forecasting ability of snowfall incidents,strengthen infrastructure construction,implement grass and livestock balance strategies,optimize livestock structure,improve loss settlement rate,and develop a modern compound model of animal husbandry development model that combines breeding,slaughtering and deep processing of animal product.展开更多
By turning to the theory of elastic thin plates, a mechanical model of the main roof breaking for severely inclined seam under long wall working was esbalished, in which formulaes were deduced for the calculation of t...By turning to the theory of elastic thin plates, a mechanical model of the main roof breaking for severely inclined seam under long wall working was esbalished, in which formulaes were deduced for the calculation of the stress distribution. When the main roof stress distribution was characterized, the failure form of the roof in the long wall coal seam under work was given with the failure criterion deduced. The deduced failure criterion was then applied to the No.3232（3） face of the Li- zuizi Coal Mine; the first pressure for the working face was accurately predicted. Results of the field application show that the main roof of the severely inclined coal seam under long wall working breaks in the O-X pattern, which is basically in accor- dance with the reality.展开更多
AIM:To study retinal microvascular and microstructural alterations in meibomian gland dysfunction(MGD)in severely obese population using optical coherence tomography angiography(OCTA).METHODS:Twelve MGD patients with ...AIM:To study retinal microvascular and microstructural alterations in meibomian gland dysfunction(MGD)in severely obese population using optical coherence tomography angiography(OCTA).METHODS:Twelve MGD patients with severely obese population(PAT group;24 eyes)and 12 healthy controls(HC group;24 eyes)were recruited.OCTA images were segmented into five[superior(S),nasal(N),inferior(I),temporal(T),and central foveal(C)]or nine[inner superior(IS),outer superior(OS),inner nasal(IN),outer nasal(ON),inner inferior(II),outer inferior(OI),inner temporal(IT),outer temporal(OT),and C]subregions.The superficial vessel density(SVD),retinal thickness(RT),foveal avascular zone(FAZ)parameters,and retinal volume were measured.RESULTS:Visual acuity was significantly different between two groups(0.8±0.17 in PAT group vs 0.2±0.06 in HC group).SVD was significantly lower in PATs in N,T,OS,IN,OT,and ON.The area under the receiver operating characteristic curve(AUC)for T was 0.961[95% confidence interval(CI):0.908 to 1.000],for OS was 0.962(95%CI:0.915 to 1.000).RT was significantly lower in PATs in IS,OS,OI,OT,ON,IT,IN,and II.AUC for OT was 0.935(95%CI:0.870 to 0.999),for IS was 0.915(95%CI:0.838 to 0.992).Angiography results showed significantly lower area and perimeter of FAZ,SVD of the inner retina and both retinal volume and the average volume thickness in the PAT group.CONCLUSION:Vision may be affected in patients with MGD due to changes in retinal microvessels and microstructures.These changes detected by OCTA may be a potential marker for diagnosing MGD in severe obesity.展开更多
This study aimed to analyze the impact of anemia on mortality rate and nutritional recovery, during severely malnourished inpatient treatment. Material and Methods: This was a retrospective cohort study conducted from...This study aimed to analyze the impact of anemia on mortality rate and nutritional recovery, during severely malnourished inpatient treatment. Material and Methods: This was a retrospective cohort study conducted from data of severely malnourished children hospitalized at a feeding the rapeutic center. Pearson’s Chi square test, General linear model, Mortality relatives risks, Kaplan-Meir survival curves have been used. Results: At admission, 85.3% of included malnourished children had anemia (Hb ≤ 11 g/dl) and 10.6% severe anemic (Hb 6 g/dl). Mortality rate did not differed significantly from severely malnourished children with anemia (12.4%) and without anemia (22.2%), p = 0.12. Kaplan Meir survival curves did not differed significantly between the two groups, (p Log Rank = 0.11). From admission to discharge, anthropometric Z-scores means evolution did not differed significantly between severely malnourished children with and without anemia at admission. But anthropometric Z-scores means evolution differed significantly within each group’s subjects: WHZ (between groups: p = 0.74;within subjects: p 0.001), and WAZ (between groups: p = 0.54;within subjects: p 0.001). Conclusion: With a strong respect of current recommendation of anemia treatment of inpatient severely malnutrition management, there is no increased mortality rate in SAM anemic group;and nutritional recovery is significant within subjects of SAM anemic and non anemic children, without difference between groups.展开更多
Children living with HIV should be diagnosed as early as possible and linked to antiretroviral treatment. The costs of HIV virological testing, individual and social implications of the disease require critical qualit...Children living with HIV should be diagnosed as early as possible and linked to antiretroviral treatment. The costs of HIV virological testing, individual and social implications of the disease require critical quality of the medical approach to diagnostic strategy. Socioeconomic data can be used to refine the medical decision. The objective of this analysis was to determine informative capacity of socioeconomic indices in the diagnosis and approach of HIV in severely malnourished children using receiver operating characteristic (ROC) curves. Materials and Methods: This was a test performance analysis conducted from data of severely malnourished children at an inpatient feeding therapeutic center in Ouagadougou. Anthropometric and social indices have been used as tests;their sensitivity, specificity and predictive values have been calculated. ROC curves and areas under curves were obtained. Medical decision aid scheme has been validated from severely malnourished children data. Results: Socioeconomic indices showed high performance to discriminate severely malnourished HIV infected and uninfected children, with high area under ROC curves. The medical decision aid scheme specificity reached 97.6% with predictive values close to 85%. Conclusion: This approach can help for expanding ART for children in low income countries and achieve the maximum ART benefits in child socioeconomic kneed context.展开更多
Introduction: Hip disarticulation (HD) consists of a removal of the entire lower limb at the height of the hip-femoral joint. It is an extremely mutilating intervention with a major functional and psychological impact...Introduction: Hip disarticulation (HD) consists of a removal of the entire lower limb at the height of the hip-femoral joint. It is an extremely mutilating intervention with a major functional and psychological impact. We report 11 cases of hip disarticulation following severe trauma of the lower limb. The aim of the study is to analyze the frequency, the clinical aspect and present their management results and the patients’ becoming. Patients and methods: A 13-year retrospective study was conducted in our traumatology department. Eleven cases of hip disarticulation were identified. We analyzed the following data: the epidemiological parameters (age, sex, accidentology), Clinico-radiological (gravity injury severity score (ISS), mangled extremity severity score (MESS), associated lesion), admission time, evolutionary aspects and finally the patients’ becoming). Results: The series consisted of 3 males and 8 females, with an average age of 24 years. All experienced a HD following the lower limb severe traumatism due to a road accident. The category of victims was dominated by pedestrians. The average admission time was 13 hours with extremes of 9 and 28 hours. Our series average ISS was 28 with extremes of 15 - 69. The associated lesions were dominated by Gustilo Type III A III B open fractures. The mean MESS at admission was 10 with extremes from 8 to 14. Complications were dominated by infection (at least 72%) with a mortality rate of 36.36%. Algohallucinosis affects all these patients post-operatively at varied degrees. Aggressive components and denial of bereavement were most noticeable. Only one patient was able to honor her Canadian prosthetic equipment. All the victims changed their personal and professional activities. Conclusion: HD is an extremely mutilating surgery with a major functional and psychological impact. Quality of life of the disarticulated patient is taught because of the persistence of the pain, the occurrence of a major motor handicap and the impossibility of apparatus limiting the social and relational life.展开更多
In low income countries, severe acute malnutrition remains a major problem for HIV-infected children and an important risk factor for mortality. This study aims to analyze HIV impact on mortality rate and nutritional ...In low income countries, severe acute malnutrition remains a major problem for HIV-infected children and an important risk factor for mortality. This study aims to analyze HIV impact on mortality rate and nutritional recovery among severely malnourished HIV/AIDS uninfected and infected children. This was a retrospective cohort study conducted from data of 521 hospitalized severely malnourished children. We used Pearson’s Chi square test to compare proportions;and Student’s independent t-test to compare means;general linear model to analyze repeated measurements. We used mortality relative risk with confidence interval (CI 95%), Kaplan-Meir survival curves and Cox proportional hazard models to analyze the HIV impact on mortality rate. Case fatality rate differed significantly from SAM HIV uninfected (10.7%) and HIV infected children (39.7%), p < 0.001. Mortality relative risk was 3.71, 95% IC [2.51 - 5.47] for HIV infected children. Kaplan-Meir survival curves differed significantly between the two groups, (p Log Rank < 0.001). Cox regression adjusted mortality relative risk of HIV infected children was 4.27, CI: 2.55 - 7.15, p < 0.001. Mean weight gain differed significantly among infected children, p < 0.001. Anthropometric Z-scores means evolution differed significantly between HIV infected and uninfected children and within each group’s subjects for WHZ (p < 0.001) and WAZ (p < 0.001). Mortality relative risk was 3.71 times higher for HIV infected children. Multiples infections and metabolic complications have synergism on death occurrence in sever acute malnutrition;when associated to HIV infection, case fatality rate increases many times. Weight gain and anthropometrics index evolution were very slow for SAM HIV infected children, and specific diet may be needed for more nutritional recovery. Effective interventions, updated and adapting to local country context, to improve survival of severely malnourished HIV/AIDS infected children in HIV and SAM prevalent settings are urgently needed in the area of SAM’s community-based treatment approach.展开更多
To explore the appropriate duration of cannulation by deep venous puncture pathway in severely burned patients during their shock reabsorb phase and 3 days thereafter.Methods This prospective study was conducted at ou...To explore the appropriate duration of cannulation by deep venous puncture pathway in severely burned patients during their shock reabsorb phase and 3 days thereafter.Methods This prospective study was conducted at our unit over two years,from Sept 1,2000 to Sept 1,2002.According to the demands of the design,given cannulated by deep venous puncture pathway,burned patients with 30% TBSA or more but without severe inhalation injuries were recruited in the present study and,were randomized into two groups,one group subjected to be cannulated with pathway-alteration within 7 days (alteration group),the other group without pathway-alteration within the similar period(non-alteration group),the incidence of CAC,CAI,and CAB was gained and compared.Results A total of 121 qualified patients had finished the study,the alteration group had 71 cases,the non-alteration group 50 cases.The incidence of CAC in non-alteration group was significant higher than that in alteration one,but the differences of the incidence of CAI and CAB between groups were insignificant.Conclusion The seven days duration of cannulation by deep venous puncture pathway in severely burned patients during their shock reabsorb phase and 3 days thereafter is safe.16 refs,2 tabs.展开更多
To investigate the surgical methods of treating severely injured vagina.Methods A retrospective study was carried out on the clinical materials and results of 7 patients suffered from severe vaginal injury.Results Dif...To investigate the surgical methods of treating severely injured vagina.Methods A retrospective study was carried out on the clinical materials and results of 7 patients suffered from severe vaginal injury.Results Different surgical approaches such as trans-suprapubic,transperineal or both approaches were applied according to the position of the atresia,meanwhile,different surgical methods such as skin graft,free flap transplantation,vaginal mucous flap advancement,direct anastomosis of the two ends,“Z” plasty was used to repair the vagina according to the different defect of the vagina,except for 1 cases complicated with vaginorecturs fistula,all the other cases were achieved satisfactory results.Conclusion The accurate judgment of the severity of the vaginal injury and the understanding of the changed anatomy around the injured vagina was the key points to the success of the surgical treatment of traumatic vaginal atresia.4 refs,3 figs,1 tab.展开更多
Objective To evaluate short-teerm clinical and radiographic results of a novel expandable pedicle screw instrumentation combined with cement augmentation in surgery for severely osteoporotic spine.Methods From October...Objective To evaluate short-teerm clinical and radiographic results of a novel expandable pedicle screw instrumentation combined with cement augmentation in surgery for severely osteoporotic spine.Methods From October 2006 to October展开更多
In this study,AA 1050 aluminum alloy and commercially pure copper in annealed and severely plastic deformed conditions were used.The technique used for imposing the severe strain to the sheets was constrained groove p...In this study,AA 1050 aluminum alloy and commercially pure copper in annealed and severely plastic deformed conditions were used.The technique used for imposing the severe strain to the sheets was constrained groove pressing（CGP） process.The annealed and severely plastic deformed sheets were subjected to friction stir welding（FSW） at different rotation and traverse speeds.Cu was placed in advancing side.Constant offset of approximately 1 mm was used toward Al side for all welds.A range of welding parameters which can lead to acceptable welds with appropriate mechanical properties was found.For the FSWed CGPed samples,it was observed that the welding heat input caused grain growth and decrease in hardness value at Al side of the stir zone.It was found that,generally the weakest parts of weld joints of annealed and CGPed samples were Al base metal and stir zone,respectively.Further investigations showed that several forms of intermetallic compounds were produced.展开更多
Magnesium(Mg)alloys have several advantages,such as low density,high specific strength and biocompatibility.However,they also suffer weak points,such as high corrosion,low formability and easy ignition,which makes the...Magnesium(Mg)alloys have several advantages,such as low density,high specific strength and biocompatibility.However,they also suffer weak points,such as high corrosion,low formability and easy ignition,which makes their applications limited.Many studies have been conducted to overcome these disadvantages and further improve the advantages of Mg alloys.Severe plastic deformation(SPD)is one of the most important techniques and has great effects on the microstructure refinement of Mg alloys and improvements in their strength and formability.Several researchers have studied the corrosion behavior of SPD-processed Mg alloys in recent decades.However,these studies have reported some controversial effects of SPD on the corrosion of Mg alloys,which makes the research roadmap ambiguous.Therefore,it is important to review the literature related to the corrosion properties of Mg alloys prepared by SPD and understand the mechanisms controlling their corrosion behavior.Effective grain refinement by SPD improves the corrosion properties of pure Mg and Mg alloys,but control of the processing conditions is a key factor for achieving this goal because texture,dislocation density,size and morphology of secondary phase also importantly affects the corrosion properties of Mg alloys.Reduced grain size in the fine grain-size range can decrease the corrosion rate due to the increased barrier effect of grain boundaries against corrosion and the formation of a stable passivation layer on the surface of fine grains.Basal texture reduces the corrosion rate because basal planes with the highest atomic planar density are more corrosion resistant than other planes.Increased dislocation density after SPD deteriorates the corrosion resistance of the interior grains and thus proper annealing after SPD is important.The fine and uniform distribution of secondary phase particles during SPD is important to minimize the micro-galvanic corrosion effect and retain small grains during annealing treatment for removing dislocations.展开更多
Microstructure and mechanical properties of AA2024 after severe plastic deformation （SPD） and non-isothermal annealing were investigated. The non-isothermal treatment was carried out on the severely deformed AA2024,...Microstructure and mechanical properties of AA2024 after severe plastic deformation （SPD） and non-isothermal annealing were investigated. The non-isothermal treatment was carried out on the severely deformed AA2024, and the interaction between restoration and precipitation phenomena was investigated. Differential scanning calorimetry, hardness and shear punch tests illustrate that static recovery and dissolution of GPB zones/Cu-Mg co-clusters occur concurrently through non-isothermal annealing. Scanning electron microscope and electron backscatter diffraction illustrate that non-isothermal annealing of deformed AA2024 up to 250 ℃ promotes the particle-free regions and also particle stimulated nucleation. Results show that through heating with the rate of 10 ℃/min up to 250 ℃, the ultimate shear strength and the hardness are maximum due to the presence of S＇/S phases which have been detected during non-isothermal differential scanning calorimetry experiment. Also, recrystallization phenomenon occurs in temperature range which includes the dissolution of S＇/S phases. The concurrent recrystallization and dissolution of S＇/S phase at 380 ℃ have been verified by differential scanning calorimetry, mechanical properties, and optical microscope.展开更多
Commercial pure copper sheets were severely deformed after primary annealing to a strain magnitude of 2.32 through constrained groove pressing. After induction of an electrical current, the sheets were heated for 0.5,...Commercial pure copper sheets were severely deformed after primary annealing to a strain magnitude of 2.32 through constrained groove pressing. After induction of an electrical current, the sheets were heated for 0.5, 1, 2, or 3 s up to maximum temperatures of 150, 200, 250, or 300℃. To compare the annealing process in the current-carrying system with that in the current-free system, four other samples were heated to 300℃ at holding times of 60, 90, 120, or 150 s in a salt bath. The microstructural evolution and hardness values of the samples were then investigated. The results generally indicated that induction of an electrical current could accelerate the recrystallization process by decreasing the thermodynamic barriers for nucleation. In other words, the current effect, in addition to the thermal effect, enhanced the diffusion rate and dislocation climb velocity. During the primary stages of recrystallization, the grown nuclei of electrically annealed samples showed greater numbers and a more homogeneous distribution than those of the samples annealed in the salt bath. In the fully recrystallized condition, the grain size of electrically annealed samples was smaller than that of conventionally annealed samples. The hardness values and metallographic images obtained indicate that, unlike the conventional annealing process, which promotes restoration phenomena with increasing heating time, the electrical annealing process does not necessarily promote these phenomena. This difference is hypothesized to stem from conflicts between thermal and athermal effects during recrystallization.展开更多
Influence of severe cold deformation of titanium alloy Ti-1.5%A1-6.8%Mo-4.5%Fe in metastable β condition on the evolution of phase composition, microstructure, and tensile properties during continuous rapid heating w...Influence of severe cold deformation of titanium alloy Ti-1.5%A1-6.8%Mo-4.5%Fe in metastable β condition on the evolution of phase composition, microstructure, and tensile properties during continuous rapid heating was studied. As-deformed alloy was characterized by quasi-amorphous single-phase β condition with an abnormal temperature dependence of electric resistance that was normalized after 48 h exposure at room temperature as a result of isothermal ω phase precipitation. Subsequent rapid heating with a rate of 5 ℃/s caused recovery and recrystallization. Tensile properties of the alloy after different treatments were determined and discussed.展开更多
文摘Introduction: In Burkina Faso, undernutrition is a public health problem associated with more than 40% of infant and child mortality. Undernutrition management is complex, and there is often a risk of treatment abandonment. Studies on this topic have not explored the influence of environmental and therapeutic factors on parental compliance. This study proposes an analysis of factors influencing the abandonment of nutritional recovery by parents of malnourished children aged 6 to 59 months in ambulatory care. Methods: This was a descriptive and exploratory qualitative study. Data collection took place in February 2020. Data were collected from seventeen (17) participants via in-depth interviews (IDI) and direct observation. The IDIs were transcribed verbatim and thematically analyzed using Nvivo software. Results: The results revealed that factors related to the physical environment, such as geographical inaccessibility, pastoral occupation, displacement at auriferous sites, and insecurity, are important causes of nutritional recovery abandonment. They also prove that factors related to the social environment, such as lack of family and social support, feelings of shame, stigmatization, occupation of the mother, and social events, lead to this abandonment. In addition, therapeutic factors such as interruptions of supplies of Ready to Use Therapeutic Food (RUTF), feeling of improvement or worsening of the state of health, recourse to traditional medicine, and ignorance of undernutrition are also associated with this issue. Conclusion: This study highlighted barriers to the abandonment of nutritional recovery among parents of severely malnourished children aged 6 to 59 months in the health district of Titao, Burkina Faso. It is more important to consider these different factors when evaluating care protocols so that policies to reduce child undernutrition can considerably impact the targets.
文摘The implementation of WHO guidelines has significantly reduced hospital mortality due to severe malnutrition. Nevertheless, severe acute malnutrition in children under five remains a major public health problem in all low-income countries and is little studied. The study aimed to assess the nutritional status and quality of management of severe acute malnutrition in children aged 06 to 59 months hospitalized in the pediatric ward of Kayanza Hospital. This is a prospective study with descriptive and analytical aims over 6 months from February 10 to July 9, 2023. All children aged 6 to 59 months admitted for severe acute malnutrition are included in this study. The results show that the most affected age group is 12 to 23 months (42.55%). Marasmus is the most common clinical form, at 70.2%. Housewives and mothers from rural areas are the most affected, with rates ranging from 69.14% to 91.49%. The study shows that the reasons for consultation are respectively: edema (29.78%), diarrhea (26.59%), vomiting (19.14%), and fever (14.89%). Dehydration and hypothermia were the main complications observed in 45.74% and 22.34% respectively. Medical treatment was provided by antibiotics (44.68%), artesunate (31.91%), and resomal (21.27%). Nutritional treatment consisted of F75 100% milk and F100 100% milk. Pathologies observed were: anemia 38.29%, malaria 37.23%, urinary tract infection 12.7%, measles 11.7%. The national protocol for integrated management of acute malnutrition (PCIMA) was followed. This study shows that 72.3% of children were successfully treated, with 9.5% dropping out and dying, and 8.5% not responding. We found that malnutrition remains a public health problem, affecting mostly children aged 12 to 24 months. The main complications or pathologies associated with malnutrition are diarrhea, malaria, and fever, and the majority of children suffer from marasmus.
基金National Natural Science Foundation of China under Grant No.51678150Science for Earthquake Resilience under Grant No.XH17064Australian Research Council Discovery Early Career Researcher Award(DECRA)
文摘In this study, three rapid repair techniques are proposed to retrofit circular bridge piers that are severely damaged by the flexural failure mode in major earthquakes. The quasi-static tests on three 1：2.5 scaled circular pier specimens are conducted to evaluate the efficiency of the proposed repair techniques. For the purpose of rapid repair, the repair procedure for all the specimens is conducted within four days, and the behavior of the repaired specimens is evaluated and compared with the original ones. A finite element model is developed to predict the cyclic behavior of the repaired specimens and the numerical results are compared with the test data. It is found that all the repaired specimens exhibit similar or larger lateral strength and deformation capacity than the original ones. The initial lateral stiffness of all the repaired specimens is lower than that of the original ones, while they show a higher lateral stiffness at the later stage of the test. No noticeable difference is observed for the energy dissipation capacity between the original and repaired pier specimens. It is suggested that the repair technique using the early-strength concrete jacket confined by carbon fiber reinforced polymer （CFRP） sheets can be an optimal method for the rapid repair of severely earthquake-damaged circular bridge piers with flexural failure mode.
文摘AIM: To evaluate the efficacy of surgical treatment of vitrectomy combined with silicone oil tamponade in the treatment of severely traumatized eyes with the visual acuity of no light perception (NLP).METHODS: This was a retrospective uncontrolled interventional case-series of 19 patients of severely traumatized eyes with NLP who underwent vitrectomy surgery at the Affiliated Hospital of Medical College, Qingdao University (Qingdao, China) during a 3-year period. We recorded perioperative factors with the potential to influence functional outcome including duration from the injury to intervention; causes for ocular trauma; open globe or closed globe injury; grade of vitreous hemorrhage; grade of endophthalmitis; grade of retinal detachment; size and location of intraocular foreign body (IOFB); extent and position of retinal defect; grade of proliferative vitreoretinopathy (PVR); type of surgery; perioperative complications and tamponade agent. The follow-up time was from 3 to 18 months, and the mean time was 12 months.RESULTS: After a mean follow-up period of 12 months (3-18 months) 10.53% (2/19) of eyes had visual acuity of between 20/60 and 20/400, 52.63% (10/19) had visual acuity less than 20/400 but more than NLP, and 36.84% (7/19) remained NLP. Visual acuity was improved from NLP to light perception (LP) or better in 63.16% (12/19) of eyes and the rate of complete retinal reattachment was 73.68% (14/19). Good visual acuity all resulted from those patients of blunt trauma with intact eyewall (closed globe injury). The perioperative factors of poor visual acuity prognosis included delayed intervention; open globe injury; endophthalmitis; severe retinal detachment; large IOFB; macular defect; a wide range of retinal defects andsevere PVR.CONCLUSION: The main reasons of NLP after ocular trauma are severe vitreous hemorrhage opacity; refractive media opacity; retinal detachment; retinal and uveal damages and defects, especially defects of the macula; PVR and endophthalmitis. NLP after ocular trauma in some cases does not mean permanent vision loss. Early intervention of vitrectomy combined with silicone oil tamponade and achieving retinal reattachment of the remaining retina, may make the severely traumatized eyes regain the VA of LP or better.
基金financially supported by the National Key R&D Program of China (No. 2018YFC1802400)the National Natural Science Foundation of China (No. 51604310)+1 种基金the Major Project of Central Research Institute of Building and Construction (No. XAC2017Ky03)the Opening Foundation of State Key Laboratory for Environmental Protection of Iron and Steel Industry (No. 2016YZC02)
文摘The stabilization of severely As-polluted soil has been a challenge, especially for the extremely toxic As(Ⅲ) contaminants. In this study, soil with a high As concentration(26084 mg/kg) was availably stabilized by a H2O2 pre-oxidation assisted TMT-15(Na3S3C3N3 solution with a mass fraction of 15%) and FeCl3·6 H2O stabilization method. The results showed that the combination of the two stabilizers(i.e., TMT-15 and FeCl3·6 H2O) presented a better stabilization behavior than either stabilizer used individually. The use of the H2O2 pre-oxidation assisted TMT-15 and FeCl3·6 H2O stabilization approach not only converted the As(Ⅲ) to As(Ⅴ) but also reduced the toxic leaching concentration of As to 1.61 mg/L, which is a safe level, when the additions of TMT-15 and FeCl3·6 H2O were 2 mL and 0.20 g, respectively. Thus, using only a simple H2O2 pre-oxidation to combine clean stabilization with non-toxic stabilizers TMT-15 and FeCl3·6 H2O could render the severely As-contaminated soil safe for disposal in a landfill.
基金supported by Open-ended Fund of Qinghai Province Key Laboratory of Physical Geography and Environmental Process(2018-QZH-K01)National Natural Science Foundation of China(41701505,41871064)the foundation of PHD development in Yichun University(201-3360118009)
文摘Historically,frequent and heavy snow disaster(SD)has caused serious livestock death and casualties,resulting in a devastating impact on animal husbandry development in the Three Rivers Source Region(TRSR).From winter in 2018 to spring in 2019,the largest SD occurred in this area over the past 10 years,especially in core zones of the Lancang River Source Region.Field research results show that the main causes of the major SD include weak infrastructure(i.e.,roads,communications,warm sheds,and insufficient forage reserve),low rate of domestic animals for sale before the SD,and low loss settlement rate.SD occurrence could furtherly reduce the ability of disaster prevention,mitigation and relief of disaster loss.In the future,heavily affected SD areas should improve the forecasting ability of snowfall incidents,strengthen infrastructure construction,implement grass and livestock balance strategies,optimize livestock structure,improve loss settlement rate,and develop a modern compound model of animal husbandry development model that combines breeding,slaughtering and deep processing of animal product.
基金Supported by the National Natural Science Foundation of China （51074005, 51004004, 51074003）
文摘By turning to the theory of elastic thin plates, a mechanical model of the main roof breaking for severely inclined seam under long wall working was esbalished, in which formulaes were deduced for the calculation of the stress distribution. When the main roof stress distribution was characterized, the failure form of the roof in the long wall coal seam under work was given with the failure criterion deduced. The deduced failure criterion was then applied to the No.3232（3） face of the Li- zuizi Coal Mine; the first pressure for the working face was accurately predicted. Results of the field application show that the main roof of the severely inclined coal seam under long wall working breaks in the O-X pattern, which is basically in accor- dance with the reality.
基金Supported by National Natural Science Foundation of China(No.82160195)Science and Technology Project of Jiangxi Provincial Department of Education(No.GJJ200169)+1 种基金Science and Technology Project of Jiangxi Province Health Commission of Traditional Chinese Medicine(No.2020A0087)Science and Technology Project of Jiangxi Health Commission(No.202130210).
文摘AIM:To study retinal microvascular and microstructural alterations in meibomian gland dysfunction(MGD)in severely obese population using optical coherence tomography angiography(OCTA).METHODS:Twelve MGD patients with severely obese population(PAT group;24 eyes)and 12 healthy controls(HC group;24 eyes)were recruited.OCTA images were segmented into five[superior(S),nasal(N),inferior(I),temporal(T),and central foveal(C)]or nine[inner superior(IS),outer superior(OS),inner nasal(IN),outer nasal(ON),inner inferior(II),outer inferior(OI),inner temporal(IT),outer temporal(OT),and C]subregions.The superficial vessel density(SVD),retinal thickness(RT),foveal avascular zone(FAZ)parameters,and retinal volume were measured.RESULTS:Visual acuity was significantly different between two groups(0.8±0.17 in PAT group vs 0.2±0.06 in HC group).SVD was significantly lower in PATs in N,T,OS,IN,OT,and ON.The area under the receiver operating characteristic curve(AUC)for T was 0.961[95% confidence interval(CI):0.908 to 1.000],for OS was 0.962(95%CI:0.915 to 1.000).RT was significantly lower in PATs in IS,OS,OI,OT,ON,IT,IN,and II.AUC for OT was 0.935(95%CI:0.870 to 0.999),for IS was 0.915(95%CI:0.838 to 0.992).Angiography results showed significantly lower area and perimeter of FAZ,SVD of the inner retina and both retinal volume and the average volume thickness in the PAT group.CONCLUSION:Vision may be affected in patients with MGD due to changes in retinal microvessels and microstructures.These changes detected by OCTA may be a potential marker for diagnosing MGD in severe obesity.
文摘This study aimed to analyze the impact of anemia on mortality rate and nutritional recovery, during severely malnourished inpatient treatment. Material and Methods: This was a retrospective cohort study conducted from data of severely malnourished children hospitalized at a feeding the rapeutic center. Pearson’s Chi square test, General linear model, Mortality relatives risks, Kaplan-Meir survival curves have been used. Results: At admission, 85.3% of included malnourished children had anemia (Hb ≤ 11 g/dl) and 10.6% severe anemic (Hb 6 g/dl). Mortality rate did not differed significantly from severely malnourished children with anemia (12.4%) and without anemia (22.2%), p = 0.12. Kaplan Meir survival curves did not differed significantly between the two groups, (p Log Rank = 0.11). From admission to discharge, anthropometric Z-scores means evolution did not differed significantly between severely malnourished children with and without anemia at admission. But anthropometric Z-scores means evolution differed significantly within each group’s subjects: WHZ (between groups: p = 0.74;within subjects: p 0.001), and WAZ (between groups: p = 0.54;within subjects: p 0.001). Conclusion: With a strong respect of current recommendation of anemia treatment of inpatient severely malnutrition management, there is no increased mortality rate in SAM anemic group;and nutritional recovery is significant within subjects of SAM anemic and non anemic children, without difference between groups.
文摘Children living with HIV should be diagnosed as early as possible and linked to antiretroviral treatment. The costs of HIV virological testing, individual and social implications of the disease require critical quality of the medical approach to diagnostic strategy. Socioeconomic data can be used to refine the medical decision. The objective of this analysis was to determine informative capacity of socioeconomic indices in the diagnosis and approach of HIV in severely malnourished children using receiver operating characteristic (ROC) curves. Materials and Methods: This was a test performance analysis conducted from data of severely malnourished children at an inpatient feeding therapeutic center in Ouagadougou. Anthropometric and social indices have been used as tests;their sensitivity, specificity and predictive values have been calculated. ROC curves and areas under curves were obtained. Medical decision aid scheme has been validated from severely malnourished children data. Results: Socioeconomic indices showed high performance to discriminate severely malnourished HIV infected and uninfected children, with high area under ROC curves. The medical decision aid scheme specificity reached 97.6% with predictive values close to 85%. Conclusion: This approach can help for expanding ART for children in low income countries and achieve the maximum ART benefits in child socioeconomic kneed context.
文摘Introduction: Hip disarticulation (HD) consists of a removal of the entire lower limb at the height of the hip-femoral joint. It is an extremely mutilating intervention with a major functional and psychological impact. We report 11 cases of hip disarticulation following severe trauma of the lower limb. The aim of the study is to analyze the frequency, the clinical aspect and present their management results and the patients’ becoming. Patients and methods: A 13-year retrospective study was conducted in our traumatology department. Eleven cases of hip disarticulation were identified. We analyzed the following data: the epidemiological parameters (age, sex, accidentology), Clinico-radiological (gravity injury severity score (ISS), mangled extremity severity score (MESS), associated lesion), admission time, evolutionary aspects and finally the patients’ becoming). Results: The series consisted of 3 males and 8 females, with an average age of 24 years. All experienced a HD following the lower limb severe traumatism due to a road accident. The category of victims was dominated by pedestrians. The average admission time was 13 hours with extremes of 9 and 28 hours. Our series average ISS was 28 with extremes of 15 - 69. The associated lesions were dominated by Gustilo Type III A III B open fractures. The mean MESS at admission was 10 with extremes from 8 to 14. Complications were dominated by infection (at least 72%) with a mortality rate of 36.36%. Algohallucinosis affects all these patients post-operatively at varied degrees. Aggressive components and denial of bereavement were most noticeable. Only one patient was able to honor her Canadian prosthetic equipment. All the victims changed their personal and professional activities. Conclusion: HD is an extremely mutilating surgery with a major functional and psychological impact. Quality of life of the disarticulated patient is taught because of the persistence of the pain, the occurrence of a major motor handicap and the impossibility of apparatus limiting the social and relational life.
文摘In low income countries, severe acute malnutrition remains a major problem for HIV-infected children and an important risk factor for mortality. This study aims to analyze HIV impact on mortality rate and nutritional recovery among severely malnourished HIV/AIDS uninfected and infected children. This was a retrospective cohort study conducted from data of 521 hospitalized severely malnourished children. We used Pearson’s Chi square test to compare proportions;and Student’s independent t-test to compare means;general linear model to analyze repeated measurements. We used mortality relative risk with confidence interval (CI 95%), Kaplan-Meir survival curves and Cox proportional hazard models to analyze the HIV impact on mortality rate. Case fatality rate differed significantly from SAM HIV uninfected (10.7%) and HIV infected children (39.7%), p < 0.001. Mortality relative risk was 3.71, 95% IC [2.51 - 5.47] for HIV infected children. Kaplan-Meir survival curves differed significantly between the two groups, (p Log Rank < 0.001). Cox regression adjusted mortality relative risk of HIV infected children was 4.27, CI: 2.55 - 7.15, p < 0.001. Mean weight gain differed significantly among infected children, p < 0.001. Anthropometric Z-scores means evolution differed significantly between HIV infected and uninfected children and within each group’s subjects for WHZ (p < 0.001) and WAZ (p < 0.001). Mortality relative risk was 3.71 times higher for HIV infected children. Multiples infections and metabolic complications have synergism on death occurrence in sever acute malnutrition;when associated to HIV infection, case fatality rate increases many times. Weight gain and anthropometrics index evolution were very slow for SAM HIV infected children, and specific diet may be needed for more nutritional recovery. Effective interventions, updated and adapting to local country context, to improve survival of severely malnourished HIV/AIDS infected children in HIV and SAM prevalent settings are urgently needed in the area of SAM’s community-based treatment approach.
文摘To explore the appropriate duration of cannulation by deep venous puncture pathway in severely burned patients during their shock reabsorb phase and 3 days thereafter.Methods This prospective study was conducted at our unit over two years,from Sept 1,2000 to Sept 1,2002.According to the demands of the design,given cannulated by deep venous puncture pathway,burned patients with 30% TBSA or more but without severe inhalation injuries were recruited in the present study and,were randomized into two groups,one group subjected to be cannulated with pathway-alteration within 7 days (alteration group),the other group without pathway-alteration within the similar period(non-alteration group),the incidence of CAC,CAI,and CAB was gained and compared.Results A total of 121 qualified patients had finished the study,the alteration group had 71 cases,the non-alteration group 50 cases.The incidence of CAC in non-alteration group was significant higher than that in alteration one,but the differences of the incidence of CAI and CAB between groups were insignificant.Conclusion The seven days duration of cannulation by deep venous puncture pathway in severely burned patients during their shock reabsorb phase and 3 days thereafter is safe.16 refs,2 tabs.
文摘To investigate the surgical methods of treating severely injured vagina.Methods A retrospective study was carried out on the clinical materials and results of 7 patients suffered from severe vaginal injury.Results Different surgical approaches such as trans-suprapubic,transperineal or both approaches were applied according to the position of the atresia,meanwhile,different surgical methods such as skin graft,free flap transplantation,vaginal mucous flap advancement,direct anastomosis of the two ends,“Z” plasty was used to repair the vagina according to the different defect of the vagina,except for 1 cases complicated with vaginorecturs fistula,all the other cases were achieved satisfactory results.Conclusion The accurate judgment of the severity of the vaginal injury and the understanding of the changed anatomy around the injured vagina was the key points to the success of the surgical treatment of traumatic vaginal atresia.4 refs,3 figs,1 tab.
文摘Objective To evaluate short-teerm clinical and radiographic results of a novel expandable pedicle screw instrumentation combined with cement augmentation in surgery for severely osteoporotic spine.Methods From October 2006 to October
基金the Research Board of Sharif University of Technology and Tamkar Industrial Company for the financial support
文摘In this study,AA 1050 aluminum alloy and commercially pure copper in annealed and severely plastic deformed conditions were used.The technique used for imposing the severe strain to the sheets was constrained groove pressing（CGP） process.The annealed and severely plastic deformed sheets were subjected to friction stir welding（FSW） at different rotation and traverse speeds.Cu was placed in advancing side.Constant offset of approximately 1 mm was used toward Al side for all welds.A range of welding parameters which can lead to acceptable welds with appropriate mechanical properties was found.For the FSWed CGPed samples,it was observed that the welding heat input caused grain growth and decrease in hardness value at Al side of the stir zone.It was found that,generally the weakest parts of weld joints of annealed and CGPed samples were Al base metal and stir zone,respectively.Further investigations showed that several forms of intermetallic compounds were produced.
基金financially supported by the National Research Foundation of Korea funded by the Korean government(MSIT)(Project No.NRF 2020R1A4A1018826)。
文摘Magnesium(Mg)alloys have several advantages,such as low density,high specific strength and biocompatibility.However,they also suffer weak points,such as high corrosion,low formability and easy ignition,which makes their applications limited.Many studies have been conducted to overcome these disadvantages and further improve the advantages of Mg alloys.Severe plastic deformation(SPD)is one of the most important techniques and has great effects on the microstructure refinement of Mg alloys and improvements in their strength and formability.Several researchers have studied the corrosion behavior of SPD-processed Mg alloys in recent decades.However,these studies have reported some controversial effects of SPD on the corrosion of Mg alloys,which makes the research roadmap ambiguous.Therefore,it is important to review the literature related to the corrosion properties of Mg alloys prepared by SPD and understand the mechanisms controlling their corrosion behavior.Effective grain refinement by SPD improves the corrosion properties of pure Mg and Mg alloys,but control of the processing conditions is a key factor for achieving this goal because texture,dislocation density,size and morphology of secondary phase also importantly affects the corrosion properties of Mg alloys.Reduced grain size in the fine grain-size range can decrease the corrosion rate due to the increased barrier effect of grain boundaries against corrosion and the formation of a stable passivation layer on the surface of fine grains.Basal texture reduces the corrosion rate because basal planes with the highest atomic planar density are more corrosion resistant than other planes.Increased dislocation density after SPD deteriorates the corrosion resistance of the interior grains and thus proper annealing after SPD is important.The fine and uniform distribution of secondary phase particles during SPD is important to minimize the micro-galvanic corrosion effect and retain small grains during annealing treatment for removing dislocations.
基金research board of Sharif University of Technology for the financial support and the provision of the research facilities used in this work
文摘Microstructure and mechanical properties of AA2024 after severe plastic deformation （SPD） and non-isothermal annealing were investigated. The non-isothermal treatment was carried out on the severely deformed AA2024, and the interaction between restoration and precipitation phenomena was investigated. Differential scanning calorimetry, hardness and shear punch tests illustrate that static recovery and dissolution of GPB zones/Cu-Mg co-clusters occur concurrently through non-isothermal annealing. Scanning electron microscope and electron backscatter diffraction illustrate that non-isothermal annealing of deformed AA2024 up to 250 ℃ promotes the particle-free regions and also particle stimulated nucleation. Results show that through heating with the rate of 10 ℃/min up to 250 ℃, the ultimate shear strength and the hardness are maximum due to the presence of S＇/S phases which have been detected during non-isothermal differential scanning calorimetry experiment. Also, recrystallization phenomenon occurs in temperature range which includes the dissolution of S＇/S phases. The concurrent recrystallization and dissolution of S＇/S phase at 380 ℃ have been verified by differential scanning calorimetry, mechanical properties, and optical microscope.
基金the research board of Sharif University of Technology for the financial support
文摘Commercial pure copper sheets were severely deformed after primary annealing to a strain magnitude of 2.32 through constrained groove pressing. After induction of an electrical current, the sheets were heated for 0.5, 1, 2, or 3 s up to maximum temperatures of 150, 200, 250, or 300℃. To compare the annealing process in the current-carrying system with that in the current-free system, four other samples were heated to 300℃ at holding times of 60, 90, 120, or 150 s in a salt bath. The microstructural evolution and hardness values of the samples were then investigated. The results generally indicated that induction of an electrical current could accelerate the recrystallization process by decreasing the thermodynamic barriers for nucleation. In other words, the current effect, in addition to the thermal effect, enhanced the diffusion rate and dislocation climb velocity. During the primary stages of recrystallization, the grown nuclei of electrically annealed samples showed greater numbers and a more homogeneous distribution than those of the samples annealed in the salt bath. In the fully recrystallized condition, the grain size of electrically annealed samples was smaller than that of conventionally annealed samples. The hardness values and metallographic images obtained indicate that, unlike the conventional annealing process, which promotes restoration phenomena with increasing heating time, the electrical annealing process does not necessarily promote these phenomena. This difference is hypothesized to stem from conflicts between thermal and athermal effects during recrystallization.
文摘Influence of severe cold deformation of titanium alloy Ti-1.5%A1-6.8%Mo-4.5%Fe in metastable β condition on the evolution of phase composition, microstructure, and tensile properties during continuous rapid heating was studied. As-deformed alloy was characterized by quasi-amorphous single-phase β condition with an abnormal temperature dependence of electric resistance that was normalized after 48 h exposure at room temperature as a result of isothermal ω phase precipitation. Subsequent rapid heating with a rate of 5 ℃/s caused recovery and recrystallization. Tensile properties of the alloy after different treatments were determined and discussed.
