Formulation of new biodegradable lubricating greases using ethylated cellulose pulp as thickener agent

J.E. Martin-Alfonso,M.J. Diaz,N. Nunez,C. Valencia,J.M. Franco 한국공업화학회 2011 Journal of Industrial and Engineering Chemistry Vol.17 No.6

The influence of cellulose pulp ethylation processing conditions has been evaluated to design suitable renewable and biodegradable lubricating greases from cellulose pulp-based gel-like dispersions. Ethyl/glucose molar ratio (E/G) has a positive effect on the ethyl groups degree of substitution (DS). Gel-like biodegradable dispersions of cellulose pulp in castor oil have been prepared by adding ethylated cellulose samples differing in the substitution degree to modify the rheological properties of castor oil. The rheology of ethyl cellulose/castor oil binary systems is highly influenced by DS. The linear viscoelastic functions and consistency are very similar to those found in traditional lithium lubricating greases.

Thermo-rheological and tribological properties of novel bio-lubricating greases thickened with epoxidized lignocellulosic materials

E. Cortés-Triviño,C. Valencia,M.A. Delgado,J.M. Franco 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.80 No.-

We examined the rheological and tribological behavior of novel formulations based on castor oil andepoxidized cellulose pulp intended for use as biodegradable lubricating greases. Epoxidized cellulosepulp was found to thicken castor oil to a variable extent depending on its modification degree andthe epoxide compound. Greases were subjected to small-amplitude oscillatory shear tests, evaluating thetemperature-dependence of the plateau modulus. In addition, friction coefficient and wear weredetermined in a steel–steel ball-on-three-plates tribological configuration, at two different temperatures(25 and 95 C), generally obtaining smaller values of both parameters when using aromatic diepoxidesinstead of aliphatic to modify the cellulose pulp.

Influence of soap/polymer concentration ratio on the rheological properties of lithium lubricating greases modified with virgin LDPE

J.E. Martin-Alfonso,G. Moreno,C. Valencia,M.C. Sanchez,C. Gallegos,J.M. Franco 한국공업화학회 2009 Journal of Industrial and Engineering Chemistry Vol.15 No.5

The main goal of this work was to study the feasibility of using a low-density polyethylene (LDPE) as additive to improve the rheological properties of lithium lubricating greases. The combined effect that both soap and LDPE concentrations exerts on the rheology of lithium lubricating greases and its relationship with grease microstructure were studied according to an experimental design based on the response surface methodology (RSM). Different lubricating grease formulations were manufactured by modifying lithium 12-hydroxystereate and LDPE concentrations. Small-amplitude oscillatory shear (SAOS) and viscous flow measurements, as well as mechanical stability tests, were performed. In addition to these, environmental scanning electronic microscopy (ESEM) was used to determine grease microstructure. LDPE was found to be a useful additive to modify grease rheology, acting as filler in the entangled soap network. The values of both apparent viscosity and linear viscoelasticity functions increase with soap and LDPE concentration. However, the addition of LDPE distorts soapmicrostructural network, yielding greases with lower relative elastic characteristics.

Development and Characterization of Novel Fibers Based on Potato Protein/Polyethylene Oxide Through Electrospinning

J.E. Martín-Alfonso,A.A. Cuadri,J.M. Franco 한국섬유공학회 2019 Fibers and polymers Vol.20 No.8

Nowadays, there is a marked tendency in order to develop new composite fibers based on proteins andpolysaccharides due to these materials can exhibit a wide range of tailored functional properties. In this framework, this studyhas been focused on the development of novel potato protein (PP)-based composite fibers by electrospinning technique usingformic acid as solvent media. At the selected electrospinning conditions, PP pure solutions (3-8 wt.%) showed inadequatespinnability. Interestingly, the addition of polyethylene oxide (PEO) as co-blending polymer improved the solutionsviscoelasticity and hence, the solutions spinnability. Composite fibers with enhanced properties were obtained at higher PEOconcentrations while systems with higher PP protein contents led to electrosprayed separate aggregates of particles. Fouriertransformedinfrared spectroscopy and thermogravimetric analysis results showed that the obtained composite fibers werecomposed of both PP and PEO materials. DSC results show that PP influences on PEO polymer thermal behaviour loweringits melting point, and an increase of the PEO amount produces a decrease of the α-helix denaturation temperature. Due to theproperties of PP and PEO, these novel composite fibers could find importance in a diverse range of applications as advancedfunctional materials in fields like food science and biomedical applications.

Electro-Oxidation in Combination with Biological Processes for Removal of Persistent Pollutants in Wastewater: A Review

Navarro-Franco, Javier A.,Garzon-Zuniga, Marco A.,Drogui, Patrick,Buelna, Gerardo,Gortares-Moroyoqui, Pablo,Barragan-Huerta, Blanca E.,Vigueras-Cortes, Juan M. The Korean Electrochemical Society 2022 Journal of electrochemical science and technology Vol.13 No.1

Persistent organic pollutants (POPs) and emerging pollutants (EP) are characterized by their difficulty to be removed through biological oxidation processes (BOPs); they persist in the environment and could have adverse effects on the aquatic ecosystem and human health. The electro-oxidation (EO) process has been successfully used as an alternative technique to oxidize many kinds of the aforementioned pollutants in wastewater. However, the EO process has been criticized for its high energy consumption cost and its potential generation of by-products. In order to decrease these drawbacks, its combination with biological oxidation processes has been reported as a solution to reduce costs and to reach high rates of recalcitrant pollutants removal from wastewaters. Thus, the location of EO in the treatment line is an important decision to make, since this decision affects the formation of by-products and biodegradability enhancement. This paper reviews the advantages and disadvantages of EO as a pre and post-treatment in combination with BOPs. A perspective of the EO scale-up is also presented, where hydrodynamics and the relationship of A/V (area of the electrode/working volume of the electrochemical cell) experiments are examined and discussed.

Formulation and processing of virgin and recycled polyolefin/oil blends for the development of lubricating greases

J.E. Martın-Alfonso,A. Romero,C. Valencia,J.M. Franco 한국공업화학회 2013 Journal of Industrial and Engineering Chemistry Vol.19 No.2

This work has been focused on the development of polyolefins/oil blends potentially suitable as lubricating greases by studying the effect that some thermo-mechanical processing variables exert on their rheological properties and microstructure. Polyolefin/oil blends have been prepared by dispersing recycled and virgin polyolefins such as high-density polyethylenes (HDPEs) and polypropylenes (PPs) in mineral lubricating oil. Linear viscoelasticity functions have been significantly influenced by processing conditions. The nature of polymers used, specially the content of HDPE, has been found to modify the microstructure of blends yielding lower mechanical stability but, on the other hand, higher values of linear viscoelastic functions.

Paravertebral block: anatomy and relevant safety issues

Alberto E Ardon,Justin Lee,Carlo D. Franco,Kevin T. Riutort,Roy A. Greengrass 대한마취통증의학회 2020 Korean Journal of Anesthesiology Vol.73 No.5

Paravertebral block, especially thoracic paravertebral block, is an effective regional anesthetic technique that can provide significant analgesia for numerous surgical procedures, including breast surgery, pulmonary surgery, and herniorrhaphy. The technique, although straightforward, is not devoid of potential adverse effects. Proper anatomic knowledge and adequate technique may help decrease the risk of these effects. In this brief discourse, we discuss the anatomy and technical aspects of paravertebral blocks and emphasize the importance of appropriate needle manipulation in order to minimize the risk of complications. We propose that, when using a landmark-based approach, limiting medial and lateral needle orientation and implementing caudal (rather than cephalad) needle redirection may provide an extra margin of safety when performing this technique. Likewise, recognizing a target that is not in close proximity to the neurovascular bundle when using ultrasound guidance may be beneficial.

In-situ magnetization measurements and ex-situ morphological analysis of electrodeposited cobalt onto chemical vapor deposition graphene/SiO₂/Si

Vin?cius C. De Franco,Gustavo M. B. Castro,Jeaneth Corredor,Daniel Mendes,Jo?o E. Schmidt 한국탄소학회 2017 Carbon Letters Vol.21 No.-

Cobalt was electrodeposited onto chemical vapor deposition (CVD) graphene/Si/SiO2 substrates, during different time intervals, using an electrolyte solution containing a low concentration of cobalt sulfate. The intention was to investigate the details of the deposition process (and the dissolution process) and the resulting magnetic properties of the Co deposits on graphene. During and after electrodeposition, in-situ magnetic measurements were performed using an (AGFM). These were followed by ex situ morphological analysis of the samples with ΔtDEP 30 and 100 s by atomic force microscopy in the non-contact mode on pristine CVD graphene/SiO2/Si. We demonstrate that it is possible to electrodeposit Co onto graphene, and that in-situ magnetic measurements can also help in understanding details of the deposition process itself. The results show that the Co deposits are ferromagnetic with decreasing coercivity (HC) and demonstrate increasing magnetization on saturation (MSAT) and electric signal proportional to remanence (Mr), as a function of the amount of the electrodeposited Co. It was also found that, after the end of the dissolution process, a certain amount of cobalt remains on the graphene in oxide form (this was confirmed by X-ray photoelectron spectroscopy), as suggested by the magnetic measurements. This oxide tends to exhibit a limited asymptotic amount when cycling through the deposition/dissolution process for increasing deposition times, possibly indicating that the oxidation process is similar to the graphene surface chemistry.

Worries and Hopes for SUSY in CKM Physics: The b → s Example

Antonio Masiero,M. Ciuchini,E. Franco,L. Silvestrini 한국물리학회 2004 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.45 No.2

We discuss the twofold r^ole of avor and CP violation as a constraint in model building and as a signal for SUSY. Considering as an example b → s transitions, we analyze present bounds on SUSY parameters, discuss possible deviations from SM predictions in Bd and Bs physics and present strategies to reveal SUSY signals in present and future experiments in the CKM domain.

Non-linear aero-elastic response of a multi-layer TPS

Pasolini, P.,Dowell, E.H.,Rosa, S. De,Franco, F.,Savino, R. Techno-Press 2017 Advances in aircraft and spacecraft science Vol.4 No.4

The aim of the present work is to present a computational study of the non-linear aero-elastic behavior of a multi-layered Thermal Protection System (TPS). The severity of atmospheric re-entry conditions is due to the combination of high temperatures, high pressures and high velocities, and thus the aero-elastic behavior of flexible structures can be difficult to assess. In order to validate the specific computational model and the overall strategy for structural and aerodynamics analyses of flexible structures, the simplified TPS sample tested in the 8' High Temperature Tunnel (HTT) at NASA LaRC has been selected as a baseline for the validation of the present work. The von $K{\acute{a}}rm{\acute{a}}n^{\prime}s$ three dimensional large deflection theory for the structure and a hybrid Raleigh-Ritz-Galerkin approach, combined with the first order Piston Theory to describe the aerodynamic flow, have been used to derive the equations of motion. The paper shows that a good description of the physical behavior of the fabric is possible with the proposed approach. The model is further applied to investigate structural and aero-elastic influence of the number of the layers and the stitching pattern.