Wet chemical surface modifications of Titanium and Ti6Al4V alloy and their effect on the hydrothermal aging mechanisms and adhesion properties

Titanium and its alloys are used in many areas of industry (aerospace, automobile, etc.). Adhesive bonding of titanium and titanium alloys is an industrial topic for approximately 40 years. However, development of new surface pre-treatments based on environmentally friendly and non toxic chemicals to improve the durability of titanium bonded joints have gained more interest in recent years. The main aims of this thesis is focused on the development and examination of non toxic and environmentally friendly pre-treatment of Ti6Al4V prior to adhesive bonding using a conversion coating and anodization process based on cerium (IV). The basic purpose of this employment is to investigate the influence of such surface treatments on the degradation mechanisms during aging of titanium oxide layer as well as on the shear strength and durability of Ti6Al4V/epoxy resin adhesive bonded joints system. This thesis also deals with the development and characterization of environmental friendly pre-treatment of pure titanium and Ti6Al4V before adhesive bonding using an etching process based on sulfuric acid. Such etching process was performed in order to generate microstructures and to increase roughness on the surface. Additionally, it was carried out to determine the hydrogen embrittlement behavior of pure titanium and Ti6Al4V alloy and its influence on the durability of bonded joints. The results show that surface treatments (conversion coating and anodization) in cerium (IV)-based solution lead to the formation of ultrathin cerium-based layers (< 10 nm) consisting of CeO2 and Ce2O3 on top of the amorphous titanium oxide. Aging tests under hot-wet conditions reveal that such layers protect titanium oxide films against hydrothermal effects whereby a kinetic stabilization is achieved, i.e. kinetic inhibition of transformation of amorphous titanium oxide into crystalline state. However, it was found that such ultrathin cerium-based oxide layers on Ti6Al4V surface are not a qualified basis layer for adhesive bonding applications due to their low cohesion strength and high affinity to carbon compounds from ambient air. The investigations of sulfuric acid etched samples reveal that a hydrogen-embrittled layer forms near the surface of pure titanium substrate whereby the durability of bonded joints is negatively affected. In the case of sulfuric acid etched Ti6Al4V, no hydrogen embrittlement is observed. The findings also show that sulfuric acid etching generates microstructures on both substrate surfaces and lead to an increase in surface roughness

Therapeutic Effects of Photobiomodulation Therapy on Multiple Sclerosis by Regulating the Inflammatory Process and Controlling Immune Cell Activity: A Novel Promising Treatment Target

Introduction: Multiple sclerosis (MS) is one of the autoimmune and chronic diseases of the central ‎nervous system, this disease occurs more frequently in young people and women ‎and leads to neurological symptoms. Oxidative stress, inflammatory process, and ‎oligodendrocyte dysfunction has a pivotal role in the pathophysiology of this ‎disease. Nowadays, it has been reported that Photobiomodulation (PBM) as a non-invasive threat has neuroprotective potential but the exact mechanisms are not understood. &nbsp;&nbsp;Methods: In this manuscript, we have reviewed the Photobiomodulation effects on MS. in this regard, we used "Photobiomodulation", " Laser therapy", and "Low-level laser therapy" keywords on MS to find related studies on this subject in PubMed, Google scholar, Elsevier, Medline, and Scopus databases.&nbsp; Results: Photobiomodulation has positive effects on MS by regulating the inflammatory ‎process, controlling immune cell activity, and mitochondrial functions, as well as inhibiting free ‎radicals’ production. ‎ Conclusion: Overall, researchers have suggested that laser therapy could be considered a promising new treatment for neurodegenerative diseases, such as multiple sclerosis

Therapeutic Effects of Combination Therapy and Photobiomodulation Therapy on Retinal Regeneration

Introduction: Macular edema (ME) is produced by central extravascular inflammation of the macula subsequent to a major loss of visual action. Macular edema can happen at any phase of diabetic retinopathy, whether non-proliferative or proliferative retinopathy. Method and material: Articles were collected from four electronic databases PubMed, Google Scholar Web of Science from 2000 to 2022 and electronically to study the effects of macular laser grid photocoagulation on Diabetic macular edema or Cystoid macular edema through the keywords " macular laser photocoagulation ", " macular edema ", " Cystoid macular edema ", " Intravitreal pharmacotherapies ", " Antivascular endothelial growth factor “, were searched about 219 articles found in google scholar and 165 articles in PubMed, that &nbsp;&nbsp;58 articles were included in the study. Result: In this study, the effects of various laser photocoagulation such as Focal and/or grid macular laser, subthreshold micropulse laser (SMPL), and Intravitreal pharmacotherapies (Corticosteroids such as triamcinolone acetonide, fluocinolone, Bevacizumab, and dexamethasone) on macular edema were investigated. A few studies had shown that the effects of corticosteroids are more effective than lasers, and a number of studies have found the effects of lasers and the combined effects of lasers with corticosteroids to be more effective. Also, some studies have also shown that the frequency and duration of follow-up and concentrations of intravitreal pharmacotherapies are effective in increasing visual outcomes. Conclusion: The results of studies showed that although corticosteroids have side effects, the combined effects of corticosteroids with subthreshold micropulse laser are effective in increasing visual acuity (VA) and central macular thickness (CMT)

Measurement of t(t)over-bar normalised multi-differential cross sections in pp collisions at root s=13 TeV, and simultaneous determination of the strong coupling strength, top quark pole mass, and parton distribution functions

Peer reviewe

An embedding technique to determine ττ backgrounds in proton-proton collision data

An embedding technique is presented to estimate standard model tau tau backgrounds from data with minimal simulation input. In the data, the muons are removed from reconstructed mu mu events and replaced with simulated tau leptons with the same kinematic properties. In this way, a set of hybrid events is obtained that does not rely on simulation except for the decay of the tau leptons. The challenges in describing the underlying event or the production of associated jets in the simulation are avoided. The technique described in this paper was developed for CMS. Its validation and the inherent uncertainties are also discussed. The demonstration of the performance of the technique is based on a sample of proton-proton collisions collected by CMS in 2017 at root s = 13 TeV corresponding to an integrated luminosity of 41.5 fb(-1).Peer reviewe

Measurement of the Splitting Function in &ITpp &ITand Pb-Pb Collisions at root&ITsNN&IT=5.02 TeV

Data from heavy ion collisions suggest that the evolution of a parton shower is modified by interactions with the color charges in the dense partonic medium created in these collisions, but it is not known where in the shower evolution the modifications occur. The momentum ratio of the two leading partons, resolved as subjets, provides information about the parton shower evolution. This substructure observable, known as the splitting function, reflects the process of a parton splitting into two other partons and has been measured for jets with transverse momentum between 140 and 500 GeV, in pp and PbPb collisions at a center-of-mass energy of 5.02 TeV per nucleon pair. In central PbPb collisions, the splitting function indicates a more unbalanced momentum ratio, compared to peripheral PbPb and pp collisions.. The measurements are compared to various predictions from event generators and analytical calculations.Peer reviewe

MUSiC : a model-unspecific search for new physics in proton-proton collisions at root s=13TeV

Results of the Model Unspecific Search in CMS (MUSiC), using proton-proton collision data recorded at the LHC at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb(-1), are presented. The MUSiC analysis searches for anomalies that could be signatures of physics beyond the standard model. The analysis is based on the comparison of observed data with the standard model prediction, as determined from simulation, in several hundred final states and multiple kinematic distributions. Events containing at least one electron or muon are classified based on their final state topology, and an automated search algorithm surveys the observed data for deviations from the prediction. The sensitivity of the search is validated using multiple methods. No significant deviations from the predictions have been observed. For a wide range of final state topologies, agreement is found between the data and the standard model simulation. This analysis complements dedicated search analyses by significantly expanding the range of final states covered using a model independent approach with the largest data set to date to probe phase space regions beyond the reach of previous general searches.Peer reviewe