Preparación, caracterización y evaluación de resina polimérica (AHMET) a partir de la reacción de anhídrido maleico con PET reciclado como inhibidor de corrosión para acero-C en HCl

Introduction: The plastic soft drink bottle from polyethylene terephthalate (PET) was introduced to consumers in 1970s. Because PET have ester group its chemical recycling is preferred. To control and reducethe environmental pollution recycling and reusing of PET has turned into an imperative procedure from the ecological perspective and it has given business opportunity because of far reaching use and accessibilityof PET polymer. Also another source of pollution to the environment was the corrosion of materials. Corrosion is the deterioration and loss of a material and its critical properties due to chemical, electrochemical and other reactions of the exposed material surface with the surrounding environment. Understanding corrosion mechanisms allow to use corrosion-resistant materials and altering designs. Organic inhibitors are very efficient to protect the metals from corrosion in all chemicals (acidic, basic and salt) media. There were many types of corrosion inhibitors and the organic inhibitor are being applied widely to protect metals from corrosion in many aggressive media. The aim of this study is to utilize waste PET-bottles will be depolarized by 2,2-dithioethanol to produce (Bis(2-((2-hydroxyethyl) thio) ethyl) terephthalate (BHTE), then by reacting of (BHTE) with maleic anhydride to produce Bis (2-((6-Mono malic acid –hydroxyethyl ester) sulfanyl) ethyl terephthalate(BHMET). The prepared (BHMET) will be used as corrosion inhibitor andits efficiency to protect the carbon steel in acidic will be assessed. Materials and Methods: Depolymerization of PET waste done with 2,2-dithioethanol. The weight proportion of PET to 2,2-dithioethanol 1:8 (wt%) and zinc acetate (0.5 wt% based on PET) was added as catalyst. Temperature of the reaction mixture was between 160-180 oC for 12 h, then the reaction mixture was kept at 140 oC for 3 h, then allowed to cool to room temperature. With vigorous agitation distilled water in excess to the reaction mixture to allow the black liquid viscous compound oligomer of Bis(2-((2-hydroxyethyl) thio) ethyl terephthalate (BHET) to precipitate. In a three neck round bottom (250 ml) attached with mechanical stirrer and thermometer (5.7gm) of (BHET) compound was added and heated for (15 min.) at (60 OC). Then (2.5gm) of malic anhydride and (1%) sulfuric acid was added. By the mechanical stirrer the mixture was mixed for (50 min.) at temperature (80OC). After the reaction the mixture was washed with distilled water to avoid the acid residue. Scheme (1) shows the mechanism for the prepared (BHMET) corrosion inhibitor

Mn(III) Catalyzed Electrochemical Reduction of CO2 on Carbon Electrodes

Though challenging, conversion of carbon dioxide (CO2) to valuable products is an emerging area of research. Electrochemical reduction (ECR) has emerged as an efficient and rapid technique to achieve this goal. Herein, 5,10,15,20-tetraphenyl-21H, 23H-porphine manganese(III) chloride [(Mn(TPP)Cl)] catalyzed CO2 reduction at vitreous carbon electrode in acetonitrile electrolyte is reported. The effect of catalyst concentration, addition of Brönsted acid (CF3CH2OH) to CO2-saturated solution have been studied and reported. Based on the results, possible mechanistic pathways have also been suggested and discussed. This work is licensed under a Creative Commons Attribution 4.0 International License

Doctor of Philosophy

dissertationThe optimization of novel stretchable fingernail sensors for detecting fingertip touch force direction is introduced. The fingernail sensor uses optical reflectance photoplethysmography to measure the change in blood perfusion in the fingernail bed when the finger pad touches a surface with various forces. This "fingernail sensing" technique involves mounting an array of LEDs (Light Emitting Diodes) and photodetectors on the fingernail surface to detect changes in the reflection intensity as a function of applied force. The intensity changes correspond to changes in blood volume underneath the fingernail and allow for fingertip force detection without haptic obstruction, which has several applications in the area of human-machine interaction. This dissertation experimentally determines the optimal optical parameters for the transmittance of light through the human fingernail bed. Specifically, the effect of varying the wavelength and optical path length on light transmittance through the nail bed are thoroughly investigated. Light transmittance through the human fingernail is optimized when using green light (525nm) and when placing optoelectronic pairs as close together as possible. The optimal locations of the optoelectronic devices are predicted by introducing an optical model that describes light transmittance between an LED and a photodiode in the fingernail area based on optical experimentation. A reduced configuration is derived from the optimal optoelectronic locations in order to facilitate iv the fabrication of the optimized fingernail sensor without significantly compromising the recognition accuracy. This results in an overall force direction recognition accuracy of 95%. Using novel fabrication techniques, we successfully build a stretchable fingernail sensor prototype, which fully conforms to the two-dimensional fingernail surface and is independent of its geometry. Namely, we overcome the challenges of patterning conductive lines on a stretchable substrate, and embedding rigid optical components in a stretchable platform while maintaining electrical conductivity. A finite element analysis is conducted to optimize the electrical contact resistance between the optoelectronic components and underlying stretchable conductors, as a function of the bending curvature and substrate thickness. The functionality of the stretchable sensor is tested in relation to the design parameters. Finally, applications and potential impacts of this work are discussed

Atypical clinical manifestation and protracted latency are observed in the emerging variant of checkpoint inhibitor-associated bullous pemphigoid

The last two decades have witnessed a substantial increase in the incidence of bullous pemphigoid (BP) worldwide.1 One of the most compelling interpretations accounting for this epidemiological observation is the growing exposure to novel drug classes that might be implicated in eliciting the disease.1 Multiple lines of evidence have recently accumulated to suggest that exposure to dipeptidyl peptidase 4 (DPP4) inhibitors and checkpoint inhibitors (CPIs) is associated with an elevated risk of BP.2,3 As these drugs were introduced only in the past two decades, their rising utilization underlies, at least in part, the growing incidence of BP.