scholarly journals Comparing in-service multi-input loads applied on non-stiff components submitted to vibration fatigue to provide specifications for robust design

2018 ◽  
Vol 165 ◽  
pp. 16004
Author(s):  
Gwenaëlle Le Corre
Keyword(s):  
Automotive Industry ◽  
Dynamic Behaviour ◽  
Limited Information ◽  
Frequency Content ◽  
Physical Test ◽  
Customer Data ◽  
Vibration Fatigue ◽  
Physical Tests ◽  
Vibration Loads

This study focuses on applications from the automotive industry, on mechanical components submitted to vibration loads. On one hand, the characterization of loading for dimensioning new structures in fatigue is enriched and updated by customer data analysis. On the other hand, the loads characterization also aims to provide robust specifications for simulation or physical tests. These specifications are needed early in the project, in order to perform the first durability verification activities. At this time, detailed information about the geometry and the material is rare. Vibration specifications need to be adapted to a calculation time or physical test durations in accordance with the pace imposed by the projects timeframe. In the trucks industry, the dynamic behaviour can vary significantly from one configuration of truck to another, as the trucks architecture impacts the load environment of the components. The vibration specifications need to be robust by taking care of the diversity of vehicles and markets considered in the scope of the projects. For non-stiff structures, the lifetime depends, among other things, on the frequency content of the loads, as well as the interactions between the components of the multi-input loads. In this context, this paper proposes an approach to compare sets of variable amplitude multi-input loads applied on non-stiff structures. The comparison is done in terms of damage, with limited information on the structure where the loads sets are applied on. The methodology is presented, as well as an application. Activities planned to validate the methodology are also exposed.

scholarly journals Molecular characterization of a ceftriaxone-resistant Neisseria gonorrhoeae strain found in Switzerland: a case report

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Konrad Egli ◽  
Anna Roditscheff ◽  
Ursula Flückiger ◽  
Martin Risch ◽  
Lorenz Risch ◽  
...  
Keyword(s):  
Neisseria Gonorrhoeae ◽  
23S Rrna ◽  
Rrna Gene ◽  
Limited Information ◽  
Specific Pcr ◽  
Appropriate Treatment ◽  
23S Rrna Gene ◽  
Allele Type ◽  
Ciprofloxacin Resistance

Abstract Background The resistance of Neisseria gonorrhoeae to ceftriaxone is unusual in Switzerland. The underlying genotype responsible for resistance is suspected to be novel. Generally, resistance in Neisseria gonorrhoeae (Ng) involves a comprehensive set of genes with many different mutations leading to resistance to different β-lactams and fluoroquinolones. Case presentation A patient had a positive result from specific PCR for Ng. We routinely culture all clinical specimens with a positive NG-PCR. In this particular case, we isolated a strain with resistance to ceftriaxone in Switzerland. A total of seven different genes (penA, ponA, porinB, mtr, gyrA, parC, 23S rRNA gene) in this strain were partially sequenced for comparison with phenotypic susceptibility testing. Interestingly, two different mutations in the porinB gene were observed, and data on this gene are limited. Information on the identified allele type of the penA gene is very limited as well. Three different mutations of parC and gyrA that correlate with ciprofloxacin resistance were found. The combination of ceftriaxone and ciprofloxacin resistance makes an appropriate treatment difficult to obtain due to multidrug resistance. Conclusion The combined results for all genes show the appearance of new mutations in central Europe either due to worldwide spread or the emergence of new genetic combinations of mutations.

scholarly journals Scrub Typhus and Molecular Characterization of Orientia tsutsugamushi from Central Nepal

Pathogens ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 422
Author(s):  
Rajendra Gautam ◽  
Keshab Parajuli ◽  
Mythili Tadepalli ◽  
Stephen Graves ◽  
John Stenos ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Scrub Typhus ◽  
Febrile Illness ◽  
Acute Febrile Illness ◽  
Limited Information ◽  
Orientia Tsutsugamushi ◽  
Health Measures ◽  
Central Nepal ◽  
Vector Borne

Scrub typhus is a vector-borne, acute febrile illness caused by Orientia tsutsugamushi. Scrub typhus continues to be an important but neglected tropical disease in Nepal. Information on this pathogen in Nepal is limited to serological surveys with little information available on molecular methods to detect O. tsutsugamushi. Limited information exists on the genetic diversity of this pathogen. A total of 282 blood samples were obtained from patients with suspected scrub typhus from central Nepal and 84 (30%) were positive for O. tsutsugamushi by 16S rRNA qPCR. Positive samples were further subjected to 56 kDa and 47 kDa molecular typing and molecularly compared to other O. tsutsugamushi strains. Phylogenetic analysis revealed that Nepalese O. tsutsugamushi strains largely cluster together and cluster away from other O. tsutsugamushi strains from Asia and elsewhere. One exception was the sample of Nepal_1, with its partial 56 kDa sequence clustering more closely with non-Nepalese O. tsutsugamushi 56 kDa sequences, potentially indicating that homologous recombination may influence the genetic diversity of strains in this region. Knowledge on the circulating strains in Nepal is important to the development of diagnostic tests and vaccines to support public health measures to control scrub typhus in this country.

scholarly journals Microstructural and Mechanical Characterization of Al-0.80Mg-0.85Si-0.3Zr Alloy

2017 ◽  
Vol 17 (4) ◽  
pp. 73-78 ◽  
Author(s):  
F. Kahrıman ◽  
M. Zeren
Keyword(s):  
Mechanical Properties ◽  
Automotive Industry ◽  
Room Temperature ◽  
Tensile Tests ◽  
Direct Chill ◽  
Peak Hardness ◽  
Casting Method ◽  
Industry Standard ◽  
Three Stages

Abstract In this study, Al-0.80Mg-0.85Si alloy was modified with the addition of 0.3 wt.-% zirconium and the variation of microstructural features and mechanical properties were investigated. In order to produce the billets, vertical direct chill casting method was used and billets were homogenized at 580 °C for 6 h. Homogenized billets were subjected to aging practice following three stages: (i) solution annealing at 550 °C for 3 h, (ii) quenching in water, (iii) aging at 180 °C between 0 and 20 h. The hardness measurements were performed for the alloys following the aging process. It was observed that peak hardness value of Al-0.80Mg-0.85Si alloy increased with the addition of zirconium. This finding was very useful to obtain aging parameters for the extruded hollow profiles which are commonly used in automotive industry. Standard tensile tests were applied to aged profiles at room temperature and the results showed that modified alloy had higher mechanical properties compared to the non-modified alloy.

scholarly journals Purification and Characterization of Antibacterial Activity against Phytopathogenic Bacteria in Culture Fluids from Ganoderma lucidum

Molecules ◽  
2021 ◽  
Vol 26 (18) ◽  
pp. 5553
Author(s):  
Loreto Robles-Hernández ◽  
Nora A. Salas-Salazar ◽  
Ana C. Gonzalez-Franco
Keyword(s):  
Antibacterial Activity ◽  
Ganoderma Lucidum ◽  
Pathogenic Bacteria ◽  
Plant Pathogens ◽  
Heat Stability ◽  
Limited Information ◽  
Dialysis Tubing ◽  
Molecular Weights ◽  
Exclusion Chromatography

Previous studies of Ganoderma lucidum have focused on its medicinal applications. Limited information is available about its antibacterial activity against plant pathogens. Thus, the goal of this study was to purify and characterize the antibacterial activity against plant pathogenic bacteria from culture fluids of G. lucidum. The nature of the bioactive components was determined using heat boiling, organic solvents, dialysis tubing, gel exclusion chromatography (GEC), proteinase sensitivity, HPLC, HPLC-APCI-MS, and GC-MS. The bioactive compounds were neither lipid, based on their solubility, nor proteic in nature, based on proteinase digestion and heat stability. The putative-bioactive polysaccharides have molecular weights that range from 3500 to 4500 Daltons as determined by dialysis tubing, GEC and APCI-MS analysis. The composition of the antibacterial compounds was determined by GC-MS. This is the first report of small polysaccharides produced by G. lucidum with activity against bacterial plant pathogens.

Physical function tests predict incident falls: A prospective study of 2969 men in the Swedish Osteoporotic Fractures in Men study

2018 ◽  
Vol 48 (4) ◽  
pp. 436-441 ◽  
Author(s):  
Marcus E. Cöster ◽  
Magnus Karlsson ◽  
Claes Ohlsson ◽  
Dan Mellström ◽  
Mattias Lorentzon ◽  
...  
Keyword(s):  
Grip Strength ◽  
Osteoporotic Fractures ◽  
The Elderly ◽  
Population Based ◽  
Hand Grip Strength ◽  
Test Time ◽  
Physical Test ◽  
Walking Test ◽  
Hand Grip ◽  
Physical Tests

Aims: Falls are common in the elderly population, and fall-related injuries are a major health issue. We investigated the ability of simple physical tests to predict incident falls. Methods: The Swedish Osteoporotic Fractures in Men (MrOS) study includes 3014 population-based men aged 69–81 years at the start of the study. These men performed five different physical tests at baseline: right-hand grip strength, left-hand grip strength, timed stand test, 6 m walking test (time and steps) and narrow walking test. During the first study year, we asked participants to fill out questionnaires regarding falls 4, 8 and 12 months after baseline. A total of 2969 men completed at least one questionnaire and were included in this study. We used generalised estimating equations and logarithmic regression models to estimate odds ratios for fallers and recurrent fallers (more than one fall during the one-year examination period) in each quartile of men for each physical test. Results: The proportions of fallers and recurrent fallers were higher in the lowest quartile of the physical tests than in the other three quartiles combined for all physical tests. A reduction of one standard deviation in respective physical test resulted in a 13–21% higher risk of becoming a faller and a 13–31% higher risk of becoming a recurrent faller. Conclusions: Low results on simple physical tests is a risk factor for incident falls in elderly Swedish men and may facilitate identification of high-risk individuals suitable for fall-intervention programs.

scholarly journals Supervised and home-based physical exercise in patients newly diagnosed with multiple myeloma—a randomized controlled feasibility study

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Rikke Faebo Larsen ◽  
Mary Jarden ◽  
Lisbeth Rosenbek Minet ◽  
Ulf Christian Frølund ◽  
Niels Abildgaard
Keyword(s):  
Multiple Myeloma ◽  
Bone Disease ◽  
Exercise Intervention ◽  
Newly Diagnosed ◽  
Test Procedures ◽  
Physical Test ◽  
Randomized Controlled ◽  
Supervised Exercise ◽  
Home Based ◽  
Physical Tests

Abstract Background The study evaluated the feasibility and safety of the exercise intervention and physical test procedures of our ongoing randomized controlled trial, examining the effect of physical exercise in newly diagnosed patients with multiple myeloma. Methods Patients are randomized 1:1 to a control group (usual care) or an intervention group (usual care and exercise) by block randomization with stratification of planned treatment, WHO performance status, and study site. The exercise intervention consists of eight supervised exercise sessions combined with home-based exercise over a 10-week period. Bone disease is systematically evaluated to determine limitations regarding physical testing and/or exercise. Feasibility outcome measures were study eligibility, acceptance, and attrition, and furthermore attendance, adherence, tolerability, and safety to the exercise intervention. Additionally, test completion, pain, and adverse events during the physical test procedures were evaluated. Outcome assessors were blinded to allocation. Results Of 49 patients screened, 30 were included. The median age was 69 years, range 38–90, 77% were males, and 67% had bone disease. Study eligibility was 82%, acceptance 75%, and attrition 20%. Attendance at supervised exercise sessions was 92%, and adherence to supervised exercise sessions and home-based exercise sessions was 99% and 89%, respectively. No serious adverse events attributed to exercise or physical tests were reported. All patients completed the physical tests, except for two patients, where physical test procedures were modified due to bone disease. Discussion The exercise intervention and physical test procedures were feasible and safe in patients with multiple myeloma, even in older patients with multiple myeloma and in patients with myeloma bone disease. Trial registration ClinicalTrials.gov. ID NCT02439112. Registered on May 7, 2015.

Force and Compression Analysis for Rigid Retaining Walls with EPS Buffer

2011 ◽  
Vol 243-249 ◽  
pp. 959-962
Author(s):  
De Ling Wang ◽  
Li Guo
Keyword(s):  
Elastic Modulus ◽  
Retaining Wall ◽  
Retaining Walls ◽  
Great Promise ◽  
Static Loads ◽  
Physical Test ◽  
Eps Geofoam ◽  
Backfill Soil ◽  
Vibration Loads ◽  
Simulation Results

In this paper, the force against rigid retaining walls from backfill soil under static loads and vibration loads is analyzed within three cases. The first case is an ordinary retaining wall without expanded polystyrene (EPS) geofoam buffer. In the second and the third case, a layer of vertical EPS buffer with different density and elastic modulus is placed between a rigid retaining wall and backfill soil. Numerical simulation results show that the force against the same retaining wall in the treated cases is less than that in the untreated case, under both static loads and vibration loads. Moreover, the compression of different EPS buffer is studied. Under vibration excitation, when the density and elastic modulus of EPS buffer decreases, its compression increases and more wall force is mitigated. Simulation results accord with the physical shaking table test data. Numerical results and physical test demonstrate that EPS geofoam seismic buffers hold great promise to reduce loads against rigid retaining wall structures, especially earthquake-induced dynamic loads.

Microstructural and Mechanical Characterization of Gray Cast Iron and AlSi Alloy after Laser Beam Hardening

2010 ◽  
Vol 638-642 ◽  
pp. 769-774 ◽  
Author(s):  
Waldemar Alfredo Monteiro ◽  
E.M.R. Silva ◽  
L.V. Silva ◽  
W. de Rossi ◽  
S.J. Buso
Keyword(s):  
Wear Resistance ◽  
Laser Beam ◽  
Automotive Industry ◽  
Automobile Industry ◽  
Gray Iron ◽  
Beam Hardening ◽  
Localized Source ◽  
Alsi Alloy ◽  
Hardening Treatment

A localized source of heat, such as that of laser beam, can provide a convenient means of producing a surface layer of altered microstructure. By using surface hardening treatment, wear resistance can be increased. Experiments were performed using a Nd:YAG pulsed laser under different processing conditions. Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray mapping (SEM) were employed to observe the effect of laser melting treatment on the microstructural properties of the samples. Depending on the selected laser treatment working conditions, different microstructures characteristics of surface melting can be achieved in the treated zone. Higher microhardness values were found at the treated area showing a superficial hardening of the sample and, consequently, an improvement of the wear resistance of these automotive alloys. The aim of this work is to find the optimal process parameters and to evaluate the characteristics of the laser superficial hardening (LSH) in a pearlitic gray iron and Al-Si alloy used in an automobile industry (bearing and piston materials in automotive industry).

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