The Influence Of Method And Environment In Torquing Screws Used In Bucket Wheel To Stacker-reclaimer Machine

Mining machines are of heavy-duty and robust type, and at the same time, they are keys to mining performance and operation. It is well known that mining environment is dirty and dusty as a whole, and this scenario contributes detrimentally for machines and equipment maintenance. This article reveals quantitatively the effect of the environment and the method in tightening screws to clamp the wheel buckets of a Stacker Reclaimer Machine at an Iron Ore Mining. For this study, a statistical tool called Minitab was utilized. The data were collected in the field during an intervention in the machine and treated statistically afterward. The elongations of the screws were measured by ultrasound which revealed that, when only torques are used to tighten the screws, referenced on the theoretical torque (N m) value, the aimed elongation (elastic strain) of screws might not be reached, with the worst case being it may be widely spread; the values obtained by ultrasound revealed such differences. After knowing such discrepancy, the screws were tightened properly to insure that the bucket wheel was correctly clamped. This statistical study quantified the spread values of torque versus elongation condition (bell curves). The ultrasound measurement credited the method utilized. © ASM International 2012.124382390Monaghan, J.M., The influence of lubrication on the design of yield tightened joints (1991) J. Strain Anal., 26 (2), pp. 124-129Luo, G.-P., Xu, L.J., Zhang, J.-G., Combination effect of fretting and corrosion on bolt-Type power connectors (2000) Proceedings Of The Forty-Sixth, pp. 60-66. , IEEE Holm Conference, Chicago(2011) Methods of Tightening Threads., , http://www.boltscience.com/pages/tighten.htm, Bolt ScienceMelkonian, S., (2009) Elementos de Máquinas, , 9a Ediçao(2010) Mechanical Engineering, , Shigley: Mechanical Engineering Design McGraw-Hill Series 9a Ediçao. McGraw-Hill, New York(2009), Minitab 15, User Manualhttp://www.metso.com, Catalogue-Metso Mining Productshttp://www.hytorc.com/products/hydraulic/avanti, Catalogue-AVANTI-Torque/Tension Machinehttp://www.ibt-usa.com/bolt_meter.html, Catalogue-USM-3 Ultrasonic Stress Mete

Generation Of Machined Multiple Flat Surfaces On Circular Bar By Its Rotation And In Synchronism With Cutting Tool

The operation of machining by lathe is one of the most common operations in automobile and machinery industries. The process is able to generate cylindrical bars under a wider variety of diameters/staggerings and using different materials, metallic's or non-metallic's (cupper, wood, aluminum, brass, steel, etc.). However, when more complex geometries are required, additional machines are used, like milling machine and/or machines under numerical control (CNC) and multiple axles. The possibility of joining circles, polygons, angular motion and synchronism, open the mind to multiple figures (shapes) and movements, which can generate different geometries. This paper aims to demonstrate that both operations (turning and milling), can be made at the same time and at the same machine, special but simpler lathe. The studies of geometry, associated with calculus (trigonometry) and angular motion give basis and sustain this statement. Tests in bench materialize the idea and reinforce this thesis.82146155Martin, J.T., Jonathan, M.B., Patrick, R.A., (1998) Fractal Geometry In Digital Imaging, p. 1. , Academic PressLandrini, M., Colagrossi, A., Greco, M., Tulin, M.P., (2012) The Fluid Mechanics of Splashing Bow Waves On Ships: A Hybrid BEM-SPH Analysis, 53, pp. 111-127. , Ocean EngineeringKline, (1972) Mathematical Thought From Ancient to Modern Times, p. 1032. , Oxford University PressFigueiredo, D.G., (2009) Análise De Fourier E Equações Diferenciais, p. 274. , Editora Projeto Euclides, in PortugueseIório, V.M., (2010) EDP: Um Curso De Graduação, p. 275. , Editora Coleção Matemática Universitária, in portugueseIório Jr., R., Iório, V.M., (2010), p. 343. , Equações Diferenciais Parciais: Uma Introdução, Editora Projeto Euclides, in PortugueseKnobloch, E., (2011) Kaspar Schott's "encyclopedia of All Mathematical Sciences", 7, pp. 225-247. , Poiesis Prax(1998) Trigonometric Delights, , by Eli Maor, Princeton University Press, Ebook version, in PDF format, full text presented(1914) Trigonometry, , by Alfred Monroe Kenyon and Louis Ingold, The Macmillan Company, In images, full text presentedhttp://www.mfg.mtu.edu/cyberman/machining.html, The John W Sutherland Research PageLiang, S.Y., Junz Wang, J.J., (1994), pp. 1177-1190. , Milling force convolution modeling for identification of cutter axis offset, International Journal of Machine Tools and ManufactureMartelloti, M.E., An analysis of the milling process (1941) Transactions of the ASME, 63, pp. 677-700Martellotti, M.E., An analysis of the milling process, Part II-Down milling (1945) Transactions of the ASME, 67, pp. 233-251Ber, A., Feldman, D., (1974) A Mathematical Model of the Radial and Axial Throw of Square Indexable Inserts In a Face Milling Cutter, pp. 19-23. , Annals of CIRP: Manufacturing TechnologyKline, W.A., Devor, R.E., The effect of runout on cutting geometry and forces in end milling (1983) International Journal of Machine Tool Design and Research, pp. 123-140Fu, H.J., Devor, R.E., Kapoor, S.G., A mechanistic model for the prediction of force system in face milling operations (1984) Transactions of the ASME: Journal of Engineering For Industry, pp. 81-88Desai, K.A., Piyush, K.A., Rao, P.V.M., Process geometry modeling with cutter runout for milling of curved surfaces (2009) International Journal of Machine Tools & Manufacture, pp. 1015-1028Boothroyd, G., Knight, W.A., (2006) Fundamentals of Machining and Machine Tools, , CRC Press, Boca Rato

Risk of chronic kidney disease after cancer nephrectomy.

The incidence of early stage renal cell carcinoma (RCC) is increasing and observational studies have shown equivalent oncological outcomes of partial versus radical nephrectomy for stage I tumours. Population studies suggest that compared with radical nephrectomy, partial nephrectomy is associated with decreased mortality and a lower rate of postoperative decline in kidney function. However, rates of chronic kidney disease (CKD) in patients who have undergone nephrectomy might be higher than in the general population. The risks of new-onset or accelerated CKD and worsened survival after nephrectomy might be linked, as kidney insufficiency is a risk factor for cardiovascular disease and mortality. Nephron-sparing approaches have, therefore, been proposed as the standard of care for patients with type 1a tumours and as a viable option for those with type 1b tumours. However, prospective data on the incidence of de novo and accelerated CKD after cancer nephrectomy is lacking, and the only randomized trial to date was closed prematurely. Intrinsic abnormalities in non-neoplastic kidney parenchyma and comorbid conditions (including diabetes mellitus and hypertension) might increase the risks of CKD and RCC. More research is needed to better understand the risk of CKD post-nephrectomy, to develop and validate predictive scores for risk-stratification, and to optimize patient management

Global, regional, and national burden of chronic kidney disease, 1990–2017 : a systematic analysis for the Global Burden of Disease Study 2017

Background Health system planning requires careful assessment of chronic kidney disease (CKD) epidemiology, but data for morbidity and mortality of this disease are scarce or non-existent in many countries. We estimated the global, regional, and national burden of CKD, as well as the burden of cardiovascular disease and gout attributable to impaired kidney function, for the Global Burden of Diseases, Injuries, and Risk Factors Study 2017. We use the term CKD to refer to the morbidity and mortality that can be directly attributed to all stages of CKD, and we use the term impaired kidney function to refer to the additional risk of CKD from cardiovascular disease and gout. Methods The main data sources we used were published literature, vital registration systems, end-stage kidney disease registries, and household surveys. Estimates of CKD burden were produced using a Cause of Death Ensemble model and a Bayesian meta-regression analytical tool, and included incidence, prevalence, years lived with disability, mortality, years of life lost, and disability-adjusted life-years (DALYs). A comparative risk assessment approach was used to estimate the proportion of cardiovascular diseases and gout burden attributable to impaired kidney function. Findings Globally, in 2017, 1·2 million (95% uncertainty interval [UI] 1·2 to 1·3) people died from CKD. The global all-age mortality rate from CKD increased 41·5% (95% UI 35·2 to 46·5) between 1990 and 2017, although there was no significant change in the age-standardised mortality rate (2·8%, −1·5 to 6·3). In 2017, 697·5 million (95% UI 649·2 to 752·0) cases of all-stage CKD were recorded, for a global prevalence of 9·1% (8·5 to 9·8). The global all-age prevalence of CKD increased 29·3% (95% UI 26·4 to 32·6) since 1990, whereas the age-standardised prevalence remained stable (1·2%, −1·1 to 3·5). CKD resulted in 35·8 million (95% UI 33·7 to 38·0) DALYs in 2017, with diabetic nephropathy accounting for almost a third of DALYs. Most of the burden of CKD was concentrated in the three lowest quintiles of Socio-demographic Index (SDI). In several regions, particularly Oceania, sub-Saharan Africa, and Latin America, the burden of CKD was much higher than expected for the level of development, whereas the disease burden in western, eastern, and central sub-Saharan Africa, east Asia, south Asia, central and eastern Europe, Australasia, and western Europe was lower than expected. 1·4 million (95% UI 1·2 to 1·6) cardiovascular disease-related deaths and 25·3 million (22·2 to 28·9) cardiovascular disease DALYs were attributable to impaired kidney function. Interpretation Kidney disease has a major effect on global health, both as a direct cause of global morbidity and mortality and as an important risk factor for cardiovascular disease. CKD is largely preventable and treatable and deserves greater attention in global health policy decision making, particularly in locations with low and middle SDI

Serum sodium concentration and the progression of established chronic kidney disease.

This is a post-peer-review, pre-copyedit version of an article published in Journal of Nephrology. The final authenticated version is available online at: https://doi.org/10.1007/s40620-018-0541-zBACKGROUND: Higher serum sodium concentration has been reported to be a risk factor for the development of incident chronic kidney disease (CKD), but its relationship with the progression of established CKD has not been investigated. We hypothesised that increased serum sodium concentration is a risk factor for estimated glomerular filtration rate (eGFR) decline in CKD. METHODS: This was a retrospective cohort study using data collected over a 6-year period, with baseline data obtained during the first 2 years. We included patients known to our renal service who had had a minimum of three blood tests every 2 years and an eGFR of < 60 mL/min/1.73 m2 at baseline. Exclusion criteria were renal replacement therapy, diabetes mellitus, heart failure and decompensated liver disease. A multiple linear regression model investigated the relationship between baseline serum sodium and eGFR decline after adjustment for confounding factors. RESULTS: 7418 blood results from 326 patients were included. There was no relationship between serum sodium concentration and estimated glomerular filtration rate at baseline. After multivariable adjustment, a 1 mmol/L increase in baseline serum sodium was associated with a 1.5 mL/min/1.73 m2 decline in eGFR during the study period (95% CI 0.9, 2.0). A reduction in eGFR was not associated with significant changes in serum sodium concentration over 6 years. CONCLUSION: Higher serum sodium concentration is associated with the progression of CKD, independently of other established risk factors. Conversely, significant alterations in serum sodium concentration do not occur with declining kidney function

Vitamin D and HIV Progression among Tanzanian Adults Initiating Antiretroviral Therapy

Background: There is growing evidence of an association between low vitamin D and HIV disease progression; however, no prospective studies have been conducted among adults receiving antiretroviral therapy (ART) in sub-Saharan Africa. Methods Serum 25-hydroxyvitamin D (25(OH)D) levels were assessed at ART initiation for a randomly selected cohort of HIV-infected adults enrolled in a trial of multivitamins (not including vitamin D) in Tanzania during 2006–2010. Participants were prospectively followed at monthly clinic visits for a median of 20.6 months. CD4 T-cell measurements were obtained every 4 months. Proportional hazard models were utilized for mortality analyses while generalized estimating equations were used for CD4 T-cell counts. Results: Serum 25(OH)D was measured in 1103 adults 9.2% were classified as vitamin D deficient (30 ng/mL). After multivariate adjustment, vitamin D deficiency was significantly associated with increased mortality as compared to vitamin D sufficiency (HR: 2.00; 95% CI: 1.19–3.37; p = 0.009), whereas no significant association was found for vitamin D insufficiency (HR: 1.24; 95% CI: 0.87–1.78; p = 0.24). No effect modification by ART regimen or change in the associations over time was detected. Vitamin D status was not associated with change in CD4 T-cell count after ART initiation. Conclusions: Deficient vitamin D levels may lead to increased mortality in individuals receiving ART and this relationship does not appear to be due to impaired CD4 T-cell reconstitution. Randomized controlled trials are needed to determine the safety and efficacy of vitamin D supplementation for individuals receiving ART

Discovery of rare variants associated with blood pressure regulation through meta-analysis of 1.3 million individuals

Correction: Volume53, Issue5 Page 762-762 DOI: 10.1038/s41588-021-00832-z Published MAY 2021Genetic studies of blood pressure (BP) to date have mainly analyzed common variants (minor allele frequency > 0.05). In a meta-analysis of up to similar to 1.3 million participants, we discovered 106 new BP-associated genomic regions and 87 rare (minor allele frequencyPeer reviewe

Dialysis initiation, modality choice, access, and prescription: conclusions from a Kidney Disease: Improving Global Outcomes (KDIGO) Controversies Conference

Globally, the number of patients undergoing maintenance dialysis is increasing, yet throughout the world there is significant variability in the practice of initiating dialysis. Factors such as availability of resources, reasons for starting dialysis, timing of dialysis initiation, patient education and preparedness, dialysis modality and access, as well as varied \u201ccountry-specific\u201d factors significantly affect patient experiences and outcomes. As the burden of end-stage kidney disease (ESKD) has increased globally, there has also been a growing recognition of the importance of patient involvement in determining the goals of care and decisions regarding treatment. In January 2018, KDIGO (Kidney Disease: Improving Global Outcomes) convened a Controversies Conference focused on dialysis initiation, including modality choice, access, and prescription. Here we present a summary of the conference discussions, including identified knowledge gaps, areas of controversy, and priorities for research. A major novel theme represented during the conference was the need to move away from a \u201cone-size-fits-all\u201d approach to dialysis and provide more individualized care that incorporates patient goals and preferences while still maintaining best practices for quality and safety. Identifying and including patient-centered goals that can be validated as quality indicators in the context of diverse health care systems to achieve equity of outcomes will require alignment of goals and incentives between patients, providers, regulators, and payers that will vary across health care jurisdictions

Body mass index and outcome in renal transplant recipients: a systematic review and meta-analysis

BACKGROUND: Whether overweight or obese end stage renal disease (ESRD) patients are suitable for renal transplantation (RT) is often debated. The objective of this review and meta-analysis was to systematically investigate the outcome of low versus high BMI recipients after RT. METHODS: Comprehensive searches were conducted in MEDLINE OvidSP, Web of Science, Google Scholar, Embase, and CENTRAL (the Cochrane Library 2014, issue 8). We reviewed four major guidelines that are available regarding (potential) RT recipients. The methodology was in accordance with the Cochrane Handbook for Systematic Reviews of Interventions and written based on the PRISMA statement. The quality assessment of studies was performed by using the GRADE tool. A meta-analysis was performed using Review Manager 5.3. Random-effects models were used. RESULTS: After identifying 5,526 studies addressing this topic, 56 studies were included. We extracted data for 37 outcome measures (including data of more than 209,000 RT recipients), of which 26 could be meta-analysed. The following outcome measures demonstrated significant differences in favour of low BMI (<30) recipients: mortality (RR = 1.52), delayed graft function (RR = 1.52), acute rejection (RR = 1.17), 1-, 2-, and 3-year graft survival (RR = 0.97, 0.95, and 0.97), 1-, 2-, and 3-year patient survival (RR = 0.99, 0.99, and 0.99), wound infection and dehiscence (RR = 3.13 and 4.85), NODAT (RR = 2.24), length of hospital stay (2.31 days), operation duration (0.77 hours), hypertension (RR = 1.35), and incisional hernia (RR = 2.72). However, patient survival expressed in hazard ratios was in significant favour of high BMI recipients. Differences in other outcome parameters were not significant. CONCLUSIONS: Several of the pooled outcome measurements show significant benefits for ‘low’ BMI (<30) recipients. Therefore, we postulate that ESRD patients with a BMI >30 preferably should lose weight prior to RT. If this cannot be achieved with common measures, in morbidly obese RT candidates, bariatric surgery could be considered. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12916-015-0340-5) contains supplementary material, which is available to authorized users

Effect of SGLT2 inhibitors on stroke and atrial fibrillation in diabetic kidney disease: Results from the CREDENCE trial and meta-analysis

BACKGROUND AND PURPOSE: Chronic kidney disease with reduced estimated glomerular filtration rate or elevated albuminuria increases risk for ischemic and hemorrhagic stroke. This study assessed the effects of sodium glucose cotransporter 2 inhibitors (SGLT2i) on stroke and atrial fibrillation/flutter (AF/AFL) from CREDENCE (Canagliflozin and Renal Events in Diabetes With Established Nephropathy Clinical Evaluation) and a meta-Analysis of large cardiovascular outcome trials (CVOTs) of SGLT2i in type 2 diabetes mellitus. METHODS: CREDENCE randomized 4401 participants with type 2 diabetes mellitus and chronic kidney disease to canagliflozin or placebo. Post hoc, we estimated effects on fatal or nonfatal stroke, stroke subtypes, and intermediate markers of stroke risk including AF/AFL. Stroke and AF/AFL data from 3 other completed large CVOTs and CREDENCE were pooled using random-effects meta-Analysis. RESULTS: In CREDENCE, 142 participants experienced a stroke during follow-up (10.9/1000 patient-years with canagliflozin, 14.2/1000 patient-years with placebo; hazard ratio [HR], 0.77 [95% CI, 0.55-1.08]). Effects by stroke subtypes were: ischemic (HR, 0.88 [95% CI, 0.61-1.28]; n=111), hemorrhagic (HR, 0.50 [95% CI, 0.19-1.32]; n=18), and undetermined (HR, 0.54 [95% CI, 0.20-1.46]; n=17). There was no clear effect on AF/AFL (HR, 0.76 [95% CI, 0.53-1.10]; n=115). The overall effects in the 4 CVOTs combined were: Total stroke (HRpooled, 0.96 [95% CI, 0.82-1.12]), ischemic stroke (HRpooled, 1.01 [95% CI, 0.89-1.14]), hemorrhagic stroke (HRpooled, 0.50 [95% CI, 0.30-0.83]), undetermined stroke (HRpooled, 0.86 [95% CI, 0.49-1.51]), and AF/AFL (HRpooled, 0.81 [95% CI, 0.71-0.93]). There was evidence that SGLT2i effects on total stroke varied by baseline estimated glomerular filtration rate (P=0.01), with protection in the lowest estimated glomerular filtration rate (45 mL/min/1.73 m2]) subgroup (HRpooled, 0.50 [95% CI, 0.31-0.79]). CONCLUSIONS: Although we found no clear effect of SGLT2i on total stroke in CREDENCE or across trials combined, there was some evidence of benefit in preventing hemorrhagic stroke and AF/AFL, as well as total stroke for those with lowest estimated glomerular filtration rate. Future research should focus on confirming these data and exploring potential mechanisms