The Influence of Lead Suspension in Oil Lubricant on the Sliding Wear Behaviour of Cast Iron

This investigation pertains to the analysis of the sliding wear response of a cast iron over a range of applied pressures in the presence of an oil lubricant. The effect of varying concentrations of lead particles suspended in the oil lubricant on the wear behaviour of the cast iron was also examined. The wear rate increased with pressure initially at a lower rate followed by a higher rate of increase beyond a specific pressure. Furthermore, the presence of suspended lead particles up to a specific concentration in the oil proved beneficial while the trend reversed at still higher concentrations. The extent of frictional heating increased with test duration at a high rate in the beginning of the tests. This was followed by a reduced rate of temperature increase at longer test durations. In some cases, the rate of temperature rise increased once again while it reduced in one case towards the end of the tests. The severity and extent of frictional heating also increased with pressure. Lead addition to the oil lubricant up to a specific concentration led to a reduced degree of heating while the trend reversed at still higher lead contents. Specimen seizure caused significantly high wear rate and frictional heating. The observed wear response of the samples has been explained in terms of specific characteristics like cracking tendency and lubricating and load bearing capacity of various microconstituents of the specimen material. Another important factor of concern affecting wear characteristics was observed to be lubricating film formation and its stability during sliding. The wear behaviour has also been substantiated through the characteristics of wear surfaces and subsurface regions

Antiinflammatory Therapy with Canakinumab for Atherosclerotic Disease

Background: Experimental and clinical data suggest that reducing inflammation without affecting lipid levels may reduce the risk of cardiovascular disease. Yet, the inflammatory hypothesis of atherothrombosis has remained unproved. Methods: We conducted a randomized, double-blind trial of canakinumab, a therapeutic monoclonal antibody targeting interleukin-1β, involving 10,061 patients with previous myocardial infarction and a high-sensitivity C-reactive protein level of 2 mg or more per liter. The trial compared three doses of canakinumab (50 mg, 150 mg, and 300 mg, administered subcutaneously every 3 months) with placebo. The primary efficacy end point was nonfatal myocardial infarction, nonfatal stroke, or cardiovascular death. RESULTS: At 48 months, the median reduction from baseline in the high-sensitivity C-reactive protein level was 26 percentage points greater in the group that received the 50-mg dose of canakinumab, 37 percentage points greater in the 150-mg group, and 41 percentage points greater in the 300-mg group than in the placebo group. Canakinumab did not reduce lipid levels from baseline. At a median follow-up of 3.7 years, the incidence rate for the primary end point was 4.50 events per 100 person-years in the placebo group, 4.11 events per 100 person-years in the 50-mg group, 3.86 events per 100 person-years in the 150-mg group, and 3.90 events per 100 person-years in the 300-mg group. The hazard ratios as compared with placebo were as follows: in the 50-mg group, 0.93 (95% confidence interval [CI], 0.80 to 1.07; P = 0.30); in the 150-mg group, 0.85 (95% CI, 0.74 to 0.98; P = 0.021); and in the 300-mg group, 0.86 (95% CI, 0.75 to 0.99; P = 0.031). The 150-mg dose, but not the other doses, met the prespecified multiplicity-adjusted threshold for statistical significance for the primary end point and the secondary end point that additionally included hospitalization for unstable angina that led to urgent revascularization (hazard ratio vs. placebo, 0.83; 95% CI, 0.73 to 0.95; P = 0.005). Canakinumab was associated with a higher incidence of fatal infection than was placebo. There was no significant difference in all-cause mortality (hazard ratio for all canakinumab doses vs. placebo, 0.94; 95% CI, 0.83 to 1.06; P = 0.31). Conclusions: Antiinflammatory therapy targeting the interleukin-1β innate immunity pathway with canakinumab at a dose of 150 mg every 3 months led to a significantly lower rate of recurrent cardiovascular events than placebo, independent of lipid-level lowering. (Funded by Novartis; CANTOS ClinicalTrials.gov number, NCT01327846.

Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

Two-body abrasion of a cast Al-Cu (2014 Al) alloy - Al2O3 particle composite : influence of heat treatment and abrasion test parameters.

An Al–Cu (2014 Al) alloy reinforced with 10 vol.% Al2O3 particles (size: 75–150 μm), prepared by liquid metallurgy route, has been investigated under two-body (high stress) abrasive wear condition. The influence of varying load, abrasive size and sliding distance on the abrasive wear behaviour of the specimens was also studied. The base alloy prepared under similar condition has also been studied under identical test conditions in order to understand the influence of the dispersoid phase on the abrasive wear characteristics of the (base) alloy. In order to assess the role of matrix microstructure, the composite as well as the base alloy was subjected to abrasion in heat treated as well as in cast conditions. The results indicate that the Al2O3 particle reinforced cast Al alloy composite was more wear resistant (less wear rate) than the (unreinforced) matrix alloy when tested against 20, 35 and 60 μm size abrasive particles over the entire range of loads and sliding distances due to protection provided by the Al2O3 particles to the alloy matrix. On the other hand, a reverse trend was observed when 100 μm size abrasive particle was used as the abrasive medium above 1 N load due to greater microcracking tendency followed by fragmentation of dispersoid/abrasive particles. Unlike cast composite, heat treated composite exhibited better wear resistance (lesser wear rate) than the matrix alloy even when the tests were conducted against 100 μm size abrasive particles over the entire range of loads and sliding distances. Matrix strengthening and the morphological changes of the precipitate particles caused lower wear rate of the heat treated base alloy and composite over the cast ones. Abrasive wear rates were observed to decrease with sliding distance because of the increased extent of clogging, capping, shelling and attrition of the abrasive particles as well as subsurface hardening of the matrix. The wear behaviour of the specimens has been explained in terms of wear-induced subsurface work hardening, protection provided by the reinforced particles (in the case of composite) and degradation of the abrasive. Material removal mechanisms have also been studied through the examination of wear surfaces, subsurfaces, debris and abrasive particles

Slurry Wear Characteristics of Zinc-Based Alloys: Effects of Sand Content of Slurry, Silicon Addition to Alloy System and Traversal Distance.

This investigation deals with the observations pertaining to the effects of specimen and slurry compositions as well as traversal distance on the slurry wear response of a zinc-based alloy. The composition of the alloy was altered by adding 4% silicon to it. The slurry composition was varied through changing the concentration of the sand particles in the range of

Effect of Sintering Atmosphere on the Corrosion and Wear Resistance of Sol-Gel Alumina-Coated Mild Steel Surface.

Sol-gel boehmite coating has been applied on mild steel substrate and sintered in inert (nitrogen) and oxygen atmospheres at 400°C to obtain a crack-free and dense lumina coating. Thereafter, its corrosion and wear resistance properties were evaluated under different exposure conditions. Fourier transform infrared (FTIR) analysis of the boehmite gel sintered in the above-mentioned atmospheres identified the presence of residual organic precursors in the gel. Microstructure and phase analyses of the sol-gel-coated surfaces were carried out using scanning electron microscopy (SEM) and x-ray diffraction (XRD) analyses, respectively. XRD analysis confirms the presence of alumina phase on the sol-gel-coated surfaces. Traces of organic groups in the gel sintered at 400°C in both of the atmospheres were noticed by FTIR analysis. Solgel- coated specimens sintered in a nitrogen atmosphere have shown a somewhat better corrosion resistance in 3.5% sodium chloride (NaCl) as compared to specimens sintered in an oxygen atmosphere. Similarly, an improved wear resistance was measured for the sol-gel-coated specimens sintered in the nitrogen atmospher

Potentiodynamic studies of modified 9Cr-1Mo ferritic steel in sulphuric acid and seawate.

The potentiodynamic behaviour of annealed and cold worked 9Cr-1Mo, modified with V0.198 wt% and Nb 0.072 wt%, ferritic steel has been studied in H2SO4 in the concentration range 0.1–5 N at a scan rate of 45 mV min−1 at 25°C. Ecorr becomes more noble while the other electrochemical parameters, i.c. icorr, icrit, ip and Ecp for both states of the modified steel decrease with the increase in acid concentration. This trend was more marked in the annealed than in the cold worked alloy. This alloy shows a higher corrosion resistance in IN H2SO4 than pure 9Cr-1Mo steel. Slight passivation at higher potential in both cold worked and annealed modified 9Cr-1Mo was observed in seawater whereas no passivation was indicated in the case of annealed pure 9Cr-1Mo steel under the same experimental condition. The different corrosion behaviour has been explained as a result of microstructural differences