Using ahp and topsis to evaluate welding processes for manufacturing plain carbon stainless steel storage tank

Purpose: In the plain carbon stainless steel storage tank manufacturing industry, there are many types of welding processes used. When selecting the most appropriate welding process is usually done intuitively by the manufacturer depending on its own pre-experiences or common applications in similar companies. However, this approach has a shortsighted view since it generally ignores many conflicting criteria effecting the suitable welding process selection. To overcome this problem, this study aims to evaluate important criteria and alternative welding processes by using some of multi-criteria decision-making approaches to come up with better manufacturing decisions. Design/methodology/approach: This study uses a combined methodology of Analytical Hierarchy Process (AHP) and Technique for Order Preference by Similarity to Ideal Solution (TOPSIS). Since both of these techniques require experts’ contributions, a group meeting is held with the experts from academia and industry. Findings: The study identified the important criteria for welding selection process in storage tank manufacturing. With the help of experts in the domain, both weights of decision criteria and ranking of alternative welding processes were determined. Research limitations/implications: Since the techniques used in the study depend on expert’s contribution, the expert knowledge on the welding process is critical. When the expert changes the resulting decision may also change. Therefore, the selection of the expert(s) must be done carefully. Practical implications: The findings of the study are valid for the specific case of the storage tank manufacturing. The study helps manufacturers to understand the framework of welding process selection and make them aware of various techniques (e.g., AHP and TOPSIS). The approach may also be welcomed by other welding applications. Originality/value: The main contribution of the study is mostly on the practical side. To the authors’ best knowledge, this paper is one of few studies investigating the selection of welding process for a plain carbon stainless steel storage tank manufacturing. It may help to increase the attention of researchers on multi-criteria decision-making applications in the welding field. © International OCSCO World Press. All rights reserved. 201

Investigations on the joint properties of the friction welding of aluminium alloy tube to tube plate using an external tool

Purpose: Aluminium and its alloys are frequently used in structural applications due to their good welding ability as well as their high strength and corrosion resistance. Several developments have been observed on the welding of aluminium in last decade. The manufacturing of heat exchangers, economizers and boilers is highly cost progress due to tube to tube plate welding’s. The purpose of this study is investigation of friction weldability of tube to tube plate aluminium alloys using an external tools (FWTPET) which is a relatively newer solid state welding process used for joining tube to tube plate. Design/methodology/approach: First, preliminary experiments were carried out to determining suitable the tool rotational speed, pressure load and temperature. An experimental setup has been designed and manufactured to keep the pressure load constant during the preliminary tests. Then, by changing the weld mouth on the plate, the gap between the tube and the plate, and the tube projection parameters, the effects of all parameters on shear strength values, micro hardness values and the formation of internal structure of the weld zone were investigated. Findings: It was founded that aluminium tubes can successfully weld to tube plates with using an external tools. Also it is seen that vertical force between tool and sample, tube protection and temperature are very important parameters which are effect of welded joint properties. Practical implications: FWTPET which is new welding method has been used in industrial field in last few years. Originality/value: In the beginnings studies concentrate on non-ferrous metals such as Al, Cu, Mg etc. So this studies on FWTPET have remarkable importance. © by International OCSCO World Press. All rights reserved

Antifungal properties and biocompatibility of silver nanoparticle coatings on silicone maxillofacial prostheses in vitro

Patients with facial prostheses suffer from yeast, Candida albicans, infections. This study aimed to determine the biocompatibility and antifungal properties of silicone facial prostheses coated with silver nanoparticles (Ag NPs) in vitro. Medical grade silicone discs were coated with 5 and 50 mg L−1 dispersions of either Ag NPs or AgNO3. Coatings were fully characterized using scanning electron microscopy and energy dispersive X‐ray spectroscopy. The biocompatibility was examined using human dermal fibroblasts (Hs68), whereas antifungal efficacy was tested against C. albicans (NCPF‐3179). The fibroblast viability was assessed by measuring lactate dehydrogenase (LDH) activity, protein content and tissue electrolytes. There were no effects on the LDH activity of fibroblast cell homogenates, and leak of LDH activity into external media remained low (0.1–0.2 IU mL−1). Sublethal effects of Ag NP coatings on membrane permeability/ion balance was not observed, as measured by stable homogenate Na+ and K+ concentrations. Some Ag (13 mg L−1) was detected from the AgNO3 coatings in the media, but total Ag remained below detection limit (<1.2 µg L−1) for the Ag NP coatings; indicating the latter were stable. When fibroblasts grown on silver coatings were challenged with C. albicans, the Ag NP coating was effective at preventing fungal growth as measured by ethanol production by the yeast, and without damaging the fibroblasts. Ethanol production decreased from 43.2 ± 25.02 in controls to 3.6 µmol mL−1 in all the silver treatments. Data shows that silicone prosthetic materials coated with Ag NPs are biocompatible with fibroblast cells in vitro and show antifungal properties. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 1038–1051, 2018.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142985/1/jbmb33917_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142985/2/jbmb33917.pd

Antibacterial Activity of Dissolved Silver Fractions Released from Silver-Coated Titanium Dental Implant Abutments: A Study on Streptococcus mutans Biofilm Formation

(1) Background: The aim of this research was to investigate the antibacterial activity of dissolved silver from silver-coated titanium implants against Streptococcus mutans. (2) Methodology: Silver-coated titanium implant discs were immersed in 1.8 mL of brain heart infusion broth (BHIB) and incubated for 24 h in order to release the silver ions into the broth. The coating quality was confirmed via EDS, and the dissolved silver was measured via inductively coupled plasma mass spectrometry (ICP-MS). The experimental design used unconditioned broth (control) and broth conditioned with silver released from silver-coated titanium implants (n = 6). Regarding the antibacterial activity, isolated Streptococcus mutans was used. A turbidity test and lactate production test were performed to determine the effect of dissolved silver on bacterial growth in a suspension and biofilm formation. (3) Result: The results showed that the coating was successfully applied on the substrate. There was around 0.3 mg/L of silver released into the BHIB, and the turbidity of the control group was significantly higher than the treatment, with measured absorbance values of 1.4 and 0.8, respectively, indicating that the dissolved silver ions from the silver-coated titanium discs exhibited some degree of antibacterial activity by preventing the growth of Streptococcus mutans. However, the results of the antibiofilm activity test did not show any significant difference between the groups. (4) Conclusion: The dissolved silver from silver-coated titanium implants has an antibacterial activity but not a significant antimicrobial activity, indicating that the dissolved silver from silver-coated titanium abutments can significantly reduce the incidence of peri-implant mucositis

Characterisation of feline renal cortical fibroblast cultures and their transcriptional response to transforming growth factor beta 1

Chronic kidney disease (CKD) is common in geriatric cats, and the most prevalent pathology is chronic tubulointerstitial inflammation and fibrosis. The cell type predominantly responsible for the production of extra-cellular matrix in renal fibrosis is the myofibroblast, and fibroblast to myofibroblast differentiation is probably a crucial event. The cytokine TGF-β1 is reportedly the most important regulator of myofibroblastic differentiation in other species. The aim of this study was to isolate and characterise renal fibroblasts from cadaverous kidney tissue of cats with and without CKD, and to investigate the transcriptional response to TGF-β1

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

International criteria for acute kidney injury: advantages and remaining challenges

• Acute Kidney Injury (AKI) is defined using widely accepted international criteria that are based on changes in serum creatinine concentration and degree of oliguria. • AKI, when defined in this way, has a strong association with poor patient outcomes, including high mortality rates and longer hospital admissions with increased resource utilisation and subsequent chronic kidney disease. • The detection of AKI using current criteria can assist with AKI diagnosis and stratification of individual patient risk. • The diagnosis of AKI requires clinical judgement to integrate the definition of AKI with the clinical situation, to determine underlying cause of AKI, and to take account of factors that may affect performance of current definitions