BAĞIMSIZ SÜSPANSİYONLU TİCARİ ARAÇLARDA ELEKTRONİK KONTROLLÜ DÜMENLEMENİN ARAŞTIRILMASI

BAĞIMSIZ SÜSPANSİYONLU TİCARİ ARAÇLARDA ELEKTRONİK KONTROLLÜ DÜMENLEMENİN ARAŞTIRILMASIÖzetBu çalışmada; hava süspansiyonlu ticari ve ticari olmayan araçlarda kullanılan dümenleme mekanizmasının Ackermann prensibi ile elektronik olarak kontrol edilip edilemeyeceği incelenmiştir. Çalışma mekaniği SolidWorks CAD programında modellenmiş, pratiksel uygulaması gerçekleştirilmiş ve Arduino işlemci kullanılarak step ve DC motorlarla kontrol denemeleri üzerinde çalışılmıştır. Step motorla adım kontrol denemesi üzerinde çalışılırken, dc motor ile zaman ve sensör verileri incelenmiştir. Çalışma mekaniği denemesi yapılan 3 model için revize edilmiş ve Arduino yazılımı üzerinde yapılan revizyonlarla çalışma tamamlanmıştır. Adım motorun adım yük ve yoldaki gürültülerden çabuk etkilenebileceği gözlemlendiğinden dolayı adım motor kontrolü yerine DC motor açı kontrolü sağlanarak yapılan çalışmadan daha iyi sonuç alınabileceği gözlemlenmiş ve çalışmanın uygulanabilirliği üzerinde durulmuştur. Mekaniğin ve döner mafsalların yataklamalarla desteklenmesi gerektiği, sürtünmenin minimuma indirip pozisyon kontrolünün doğru yapılması durumunda DC motordan verim alınabileceği gözlemlenmiş, hassaslığın daha önemli olması durumunda servo motor da kullanılabileceği üzerinde durulmuştur.Anahtar Kelimeler: Ağır vasıta araçları, elektronik kontrol dümenleme mekanizması, süspansiyon sistemi, Ackermann elektronik uygulamasıINVESTIGATION OF ELECTRONICALLY CONTROLLED STEERING SYSTEM IN INDEPENDENT SUSPENSION EQUIPPED COMMERCIAL VEHICLESAbstractIn this study; we research that whether the steering mechanism is used in commercial or non-commercial vehicles can be controlled electronically with the Ackermann model. The working mechanics were modeled in SolidWorks CAD program, practical application was performed and controlled with Arduino processor by using stepper and DC motors. Step control experiment was carried out with step motor, time and sensor analyzed experiment was carried with dc motor. The study was revised for the 3 models that were tested mechanics and the study was completed with revisions made on Arduino software. Cause of the stepper motor step jumping problem; instead of the stepper motor, DC motor close circuit control is made possible. It was observed that the mechanics and rotary joints should be supported with bearings, if the friction is minimized and the position control is performed correctly, the efficiency can be obtained from the DC motor and the servo motor can be used if the accuracy is more important. Keywords: heavy vehicles, electronic control steering mechanism, suspension system, Ackermann electronic applicatio

A new circular mapping-guided approach for endoscopic laser balloon pulmonary vein isolation

AbstractBackgroundPulmonary vein isolation (PVI) for atrial fibrillation (AF) is performed with the endoscopically assisted laser balloon ablation system (EAS). We hypothesized that placement of a circular mapping catheter (CMC) in the pulmonary vein (PV) distal to the laser balloon during ablation is feasible and safe.MethodsOut of 58 included patients, 37 underwent mapping-guided EAS PVI, with the CMC inside the PV during laser ablation, and 21 patients underwent standard EAS PVI, with the CMC outside the PV during laser ablation.ResultsMean age was 56years and 81% had paroxysmal AF. In the mapping-guided ablation group, 91% of PVs were isolated with the CMC in the PV during EAS ablation, isolation was completed in 9% of PVs after the CMC was removed from the PV. After passing a learning curve in 18 patients, a significant drop in unsuccessfully isolated PVs was observed in the mapping guided EAS PVI group (15% to 4%, P=0.020). No major complications were seen in the mapping-guided EAS PVI group. However, in the standard EAS PVI group, laser ablation was complicated by a temporary phrenic nerve palsy in 1 patient. After a median follow-up of 16.7months, there was no statistical difference in AF free survival among treatment groups (mapping-guided: 56% vs. 52%, P=0.875).ConclusionMapping guided EAS PVI with a distal CMC in the PV during laser ablation is feasible and seems safe as the standard EAS PVI approach

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

Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study

Background: Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world. Methods: This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the GlobalSurg 1 study and other studies that have been found to affect the likelihood of SSI were entered into risk adjustment models. The primary outcome measure was the 30-day SSI incidence (defined by US Centers for Disease Control and Prevention criteria for superficial and deep incisional SSI). Relationships with explanatory variables were examined using Bayesian multilevel logistic regression models. This trial is registered with ClinicalTrials.gov, number NCT02662231. Findings: Between Jan 4, 2016, and July 31, 2016, 13 265 records were submitted for analysis. 12 539 patients from 343 hospitals in 66 countries were included. 7339 (58·5%) patient were from high-HDI countries (193 hospitals in 30 countries), 3918 (31·2%) patients were from middle-HDI countries (82 hospitals in 18 countries), and 1282 (10·2%) patients were from low-HDI countries (68 hospitals in 18 countries). In total, 1538 (12·3%) patients had SSI within 30 days of surgery. The incidence of SSI varied between countries with high (691 [9·4%] of 7339 patients), middle (549 [14·0%] of 3918 patients), and low (298 [23·2%] of 1282) HDI (p < 0·001). The highest SSI incidence in each HDI group was after dirty surgery (102 [17·8%] of 574 patients in high-HDI countries; 74 [31·4%] of 236 patients in middle-HDI countries; 72 [39·8%] of 181 patients in low-HDI countries). Following risk factor adjustment, patients in low-HDI countries were at greatest risk of SSI (adjusted odds ratio 1·60, 95% credible interval 1·05–2·37; p=0·030). 132 (21·6%) of 610 patients with an SSI and a microbiology culture result had an infection that was resistant to the prophylactic antibiotic used. Resistant infections were detected in 49 (16·6%) of 295 patients in high-HDI countries, in 37 (19·8%) of 187 patients in middle-HDI countries, and in 46 (35·9%) of 128 patients in low-HDI countries (p < 0·001). Interpretation: Countries with a low HDI carry a disproportionately greater burden of SSI than countries with a middle or high HDI and might have higher rates of antibiotic resistance. In view of WHO recommendations on SSI prevention that highlight the absence of high-quality interventional research, urgent, pragmatic, randomised trials based in LMICs are needed to assess measures aiming to reduce this preventable complication

Renin turning full circle as cardiovascular risk factor

status: publishe

Analytical and finite element solution of a receding contact problem

ADIYAMAN, GOKHAN/0000-0002-3076-4090WOS: 000352412000011In this paper, a receding contact problem for an elastic layer resting on two quarter planes is considered. the layer is pressed by a stamp and distributed loads. It is assumed that the contact surfaces are frictionless and only compressive traction can be transmitted through the contact surfaces. in addition the effect of body forces are neglected. Firstly, the problem is solved analytically based on theory of elasticity. in this solution, the problem is reduced into a system of singular integral equations in which contact areas and contact stresses are unknowns using boundary conditions and integral transform techniques. This system is solved numerically using Gauss-Jacobi integral formulation. Secondly, two dimensional finite element analysis of the problem is carried out using ANSYS. the dimensionless quantities for the contact areas and the contact pressures are calculated under various distributed load conditions using both solutions. It is concluded that the position and the magnitude of the distributed load have an important role on the contact area and contact pressure distribution between layer and quarter plane contact surface. the analytic results are verified by comparison with finite element results

ANALYSIS OF A LONG STRIP CONTAINING AN INTERNAL OR EDGE CRACK USING FEM

WOS: 000379848700013This paper presents the elastostatic plane problem of a long strip containing an internal or edge crack perpendicular to its boundaries. the plane problem consists of an infinitely long strip of thickness h. the infinitely long strip is loaded by uniformly distributed load and rests on two simple supports. It is assumed that the effect of gravity is neglected. the finite element model of the problem is constituted using ANSYS software and the two dimensional analysis of the problem is carried out. Normalized stress-intensity factors for the cases with internal and edge crack, and normal stress (sigma(x)) for uncracked layer case are obtained for various dimensionless quantities. Finally, the results obtained from the finite element analysis are verified by comparing with analytical ones and it is seen that the results from finite element analysis indicate a good agreement with the analytical solution

A new circular mapping-guided approach for endoscopic laser balloon pulmonary vein isolation

Pulmonary vein isolation (PVI) for atrial fibrillation (AF) is performed with the endoscopically assisted laser balloon ablation system (EAS). We hypothesized that placement of a circular mapping catheter (CMC) in the pulmonary vein (PV) distal to the laser balloon during ablation is feasible and safe. Out of 58 included patients, 37 underwent mapping-guided EAS PVI, with the CMC inside the PV during laser ablation, and 21 patients underwent standard EAS PVI, with the CMC outside the PV during laser ablation. Mean age was 56 years and 81% had paroxysmal AF. In the mapping-guided ablation group, 91% of PVs were isolated with the CMC in the PV during EAS ablation, isolation was completed in 9% of PVs after the CMC was removed from the PV. After passing a learning curve in 18 patients, a significant drop in unsuccessfully isolated PVs was observed in the mapping guided EAS PVI group (15% to 4%, P = 0.020). No major complications were seen in the mapping-guided EAS PVI group. However, in the standard EAS PVI group, laser ablation was complicated by a temporary phrenic nerve palsy in 1 patient. After a median follow-up of 16.7 months, there was no statistical difference in AF free survival among treatment groups (mapping-guided: 56% vs. 52%, P = 0.875). Mapping guided EAS PVI with a distal CMC in the PV during laser ablation is feasible and seems safe as the standard EAS PVI approach

Examination of analytical and finite element solutions regarding contact of a functionally graded layer

WOS: 000590769000004In this study, the continuous and discontinuous contact problems of functionally graded (FG) layer resting on a rigid foundation were considered. the top of the FG layer was loaded by a distributed load. It was assumed that the shear modulus and the density of the layer varied according to exponential functions along the depth whereas the the Poisson ratio remained constant. the problem first was solved analytically and the results were verified with the ones obtained from finite element (FE) solution. in analytical solution, the stress and displacement components for FG layer were obtained by the help of Fourier integral transform. Critical load expression and integral equation for continuous and discontinuous contact, respectively, using corresponding boundary conditions in each case. the finite element solution of the problem was carried out using ANSYS software program. in continuous contact case, initial separation distance and contact stresses along the contact surface between the FG layer and the rigid foundation were examined. Separation distances and contact stresses were obtained in case of discontinuous contact. the effect of material properties and loading were investigated using both analytical and FE solutions. It was shown that obtained results were compatible with each other.Scientific and Technological Research Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [216M524]The research described in this paper was financially supported by the the Scientific and Technological Research Council of Turkey (TUBITAK) for their financial support [Project number: 216M524]