Effect of antimony on the eutectic reaction of heavy section spheroidal graphite castings

There is a strong demand for heavy section castings made of spheroidal graphite with a fully ferritic matrix, e.g. for manufacturing hubs for windmills. Such castings with slow solidification process are prone to graphite degeneration that leads to a dramatic decrease of the mechanical properties of the cast parts. Chunky graphite is certainly the most difficult case of graphite degeneracy, though it has long been known that the limited and controlled addition of antimony may help eliminate it. The drawback of this remedy is that too large Sb additions lead to other forms of degenerate graphite, and also that antimony is a pearlite promoter. As part of an investigation aimed at mastering low level additions to cast iron melts before casting, solidification of large blocks with or without Sb added was followed by thermal analysis. Comparison of the cooling curves and of the microstructures of these different castings gives suggestions to understand the controlling nucleation and growth mechanisms for chunky graphite cells

Polariton panorama

In this brief review, we summarize and elaborate on some of the nomenclature of polaritonic phenomena and systems as they appear in the literature on quantum materials and quantum optics. Our summary includes at least 70 different types of polaritonic light–matter dressing effects. This summary also unravels a broad panorama of the physics and applications of polaritons. A constantly updated version of this review is available at https://infrared.cni.columbia.edu

Neuropathic pain after thoracotomy: tracking signs and symptoms before and at monthly intervals following surgery

Background: Because the development of neuropathic symptoms contributes to pain severity and chronification after surgery, their early prediction is important to allow targeted treatment. Objectives: We longitudinally investigated trajectories of signs and symptoms in patients undergoing thoracotomy and assessed whether and at which time they were related to the development of neuropathic pain symptoms six months after surgery. Methods: Presurgical and six, monthly postsurgical assessments included questionnaires for mental and physical well-being (e.g. depression/anxiety, pain catastrophizing, sleep quality, neuropathic pain symptoms), and quantitative sensory testing (QST). Results: QST trajectories indicated nerve impairment of the surgery site with predominant loss of function. Signs of recovery towards the end of the assessment period were observed for some tests. Unsupervised cluster analysis with NPSI scores six months after surgery as clustering variable identified one group with no/low levels of neuropathic symptoms and one with moderate levels. The two groups differed w.r.t. several signs and symptoms already at early time points. Notably, neuropathic pain anywhere in the body differed already preoperatively and sleep impairment differentiated the two groups at all time points. Regression analysis revealed three factors that seemed particularly suited to predicted six months NPSI scores, namely preoperative neuropathic pain symptoms, with contributions from sleep impairment one month after surgery and the presence of dynamic mechanical allodynia three months after surgery. Conclusions: Clinical routine should focus on the individual’s physiological state, including pre-existing neuropathic pain and sleep quality to identify patients early who might be at risk to develop chronic post-surgical neuropathic pain

Effect of Antimony and Cerium on the Formation of Chunky Graphite during Solidification of Heavy-Section Castings of Near-Eutectic Spheroidal Graphite Irons

Thermal analysis is applied to the study of the formation of chunky graphite (CHG) in heavysection castings of spheroidal graphite cast irons. To that aim, near-eutectic melts prepared in one single cast house were poured into molds containing up to four large cubic blocks 30 cm in size. Four melts have been prepared and cast that had a cerium content varying in relation with the spheroidizing alloy used. Postinoculation or addition of antimony was achieved by fixing appropriate amounts of materials in the gating system of each block. Cooling curves recorded in the center of the blocks show that solidification proceeds in three steps: a short primary deposition of graphite followed by an initial and then a bulk eutectic reaction. Formation of CHG could be unambiguously associated with increased recalescence during the bulk eutectic reaction. While antimony strongly decreases the amount of CHG, it appears that the ratio of the contents in antimony and cerium should be higher than 0.8 in order to avoid this graphite degeneracy

Chemical physics insight of PPy-based modified ion exchange membranes: a fundamental approach

Four commercially available, cost-effective ion exchange membranes (two cationic and two anionic exchange membranes, CEMs and AEMs, respectively) were modified to mitigate crossover phenomena of the redox active species typically observed in Aqueous Organic Redox Flow Batteries (AORFB) systems. The modification strategy was carried out using a pyrrole(Py)-based polymer which successfully reduced the permeation of two redox active organic molecules, a viologen derivative (named BP7 throughout this study) and TEMPOL, by an order of magnitude. Additionally, modified membranes showed not significant changes in ion conductivity, with negligible effect on the electrical conductivity of the membranes at a given conditions. The morphology, physicochemical, mechanical, and electrochemical properties of the membranes were determined to evaluate the impact of these modifications. AEMs modified in this manner were found to have optimal properties, showing an increase in ion exchange capacity while maintaining excellent mechanical stability and unaltered permselectivity. Additionally, the diffusion boundary layer of these AEMs was slightly extended, which suggests a greater double layer stability for ion exchange processes than in the case of CEMs. Our work shows that these modified membranes could be an appealing approach for AORFB applicationsThis work has been funded by the European Union under the HIGREEW project, Affordable High-performance Green Redox Flow batteries (Grant agreement no. 875613). H2020: LC-BAT-4-2019875613

Aminopirimidinas y derivados. 25. Síntesis de intermedios versátiles para la preparación de 7-glicosilpurinas

Se han preparado 5-formilamino-4-glicosilaminopirimidinas (IV), por reacción de los correspondientes 5-amino derivados (III) con ácido fórmico. Los compuestos III se prepararon por nitrosación de las 4-glicosilaminopirimidinas (I) y posterior reducción de los 5-nitroso derivados (II). Todas estas reacciones transcurren con rendimientos elevados y en condiciones de reacción muy suaves.5-Formylamino-4-glycosylaminopyrimidines (IV) have been obtained by reaction of the corresponding 5-amino derivatives (111) with formic acid. Compounds III were prepared by nitrosation of the 4-g1ycosylaminopyrimidines (1) and subsequent reduction of the 5-nitroso derivatives (H) thus obtained. AH these reactions took place in high yields and under very mi Id conditions

Copper deposition on fabrics by rf plasma sputtering for medical applications

https://www.scopus.com/inward/record.url?eid=2-s2.0-84938151607&partnerID=40&md5=bf2da795caced442546f442aa330773aThe present work is about preparation and characterization of RF sputtered Cu films on cotton by the usage of a Magnetron Sputter Source and 99.995% purity Cu target at room temperature. Cotton fabric samples of 1, 2 and 4 min of sputtering time at discharge pressure of 1×10-2 Torr and distance between target and sample of 8 cm were used. The main goal was to qualitatively test the antimicrobial action of copper on fabrics. For that purpose, a reference strain of Escherichia Coli ATCC 35218 that were grown in TSA plates was implemented. Results indicated a decrease in the growth of bacteria by contact with Cu; for fabric samples with longer sputtering presented lower development of E. coli colonies. The scope of this research focused on using these new textiles in health field, for example socks can be made with this textile for the treatment of athlete's foot and the use in pajamas, sheets, pillow covers and robes in hospital setting for reducing the spread of microorganisms. © Published under licence by IOP Publishing Ltd.Ad Astra Rocket Company,Instituto Tecnologico de Costa Rica,International Atomic Energy Agency (IAEA),Universidad Nacional de Costa Ric

Aminopirimidinas y derivados. 25. Síntesis de intermedios versátiles para la preparación de

5-Formylamino-4-glycosylaminopyrimidines (IV) have been obtained by reaction of the corresponding 5-amino derivatives (III) with formic acid. Compounds III were prepared by nitrosation of the 4-glycosylaminopyrimidines (I) and subsequent reduction of the 5-nitroso derivatives (II) thus obtained. All these reactions took place in high yields and under very mi Id conditions.Se han preparado 5-formilamino-4-glicosilaminopirimidinas (IV), por reacción de los correspondientes 5-amino derivados (III) con ácido fórmico. Los compuestos III se prepararon por nitrosación de las 4-glicosilaminopirimidinas (I) y posterior reducción de los 5-nitroso derivados (II). Todas estas reacciones transcurren con rendimientos elevados y en condiciones de reacción muy suaves

“Condensación de 4-Aminopirimidinas con galactosa”

4-N-glycolsides (II) were prepared by reaction of 4-amino-1,6-dihydro-2- methylthio-6-oxo-pyrimidine (Ia) and 4-amino-1,6-dihydro-1-methylthio-6-oxo-pyrimidine (Ib) with galactose. Their acetyl derivatives III, were obtained by acetylation of the corresponding II with acetic anhydride and pyridine.Se obtienen los 4-N-glicósidos II, por reacción de 4-amino-1,6-dihidro-2- metiltio-6-oxo-pirimidina (Ia) y 4-amino-1,6-dihidro-1-metil-2-metiltio-6-oxopirimidina (Ib) con galactosa. Los compuestos II se acetilan con anhidrido acético y piridina, obteniéndose los correspondientes derivados acetilados III