A Cleaner Milling Process Replacing Emulsion Coolant by Cryogenics CO2

Octavio M. Pereira Neto,Calleja‑Ochoa,I. Ayesta,A. Rodríguez,H. González‑Barrio,L. N. López de Lacalle 한국정밀공학회 2024 International Journal of Precision Engineering and Vol.11 No.1

In manufacturing sector, looking for a balance between environmental and technical efficiency taking into account productivity is mandatory. Some sectors, such as the biomedical manufacturing sector, also needs to consider the cleanness inherent to prosthesis manufacturing processes for avoiding pathogens transfer to the human body, that is, neither chemicals, bacteria, nor uncontrolled metals can be introduced during the surgical intervention. This work here presented stems from the idea of analyzing the cleanness of cryogenic cooling to be applied to medical pieces. For this, several samples were machined using CO2 cryogenic technology and oil emulsions, respectively. In particular, a modified milling tool was used to apply not only efficiently as cutting fluid but also as cleaner fluid. Afterwards, they were analyzed by Scanning Electron Microscope (SEM) with the aim of looking for biological remains. Finally, with the aim of validating the modified tool in which CO2 is introduced axially as internal coolant, its tool life was tested in comparison with a conventional one. The results shown that the use of CO2 as internal coolant significantly improves the cleanness of current machining processes in comparison with the use of oil emulsions and the way in which is injected does not affect to machining performance.

Review : Targeting the Osmotic Stress Response for Strain Improvement of an Industrial Producer of Secondary Metabolites

( Octavio Godinez ),( Paul Dyson ),( Ricardo Del Sol ),( Javier Barrios Gonzalez ),( Cesar Millan Pacheco ),( Armando Mejia ) 한국미생물 · 생명공학회 2015 Journal of microbiology and biotechnology Vol.25 No.11

The transition from primary to secondary metabolism in antibiotic-producing Streptomyces correlates with expression of genes involved in stress responses. Consequently, regulatory pathways that regulate specific stress responses are potential targets to manipulate to increase antibiotic titers. In this study, genes encoding key proteins involved in regulation of the osmotic stress response in Streptomyces avermitilis, the industrial producer of avermectins, are investigated as targets. Disruption of either osaBSa, encoding a response regulator protein, or osaCSa, encoding a multidomain regulator of the alternative sigma factor SigB, led to increased production of both oligomycin, by up to 200%, and avermectin, by up to 37%. The mutations also conditionally affected morphological development; under osmotic stress, the mutants were unable to erect an aerial mycelium. In addition, we demonstrate the delivery of DNA into a streptomycete using biolistics. The data reveal that information on stress regulatory responses can be integrated in rational strain improvement to improve yields of bioactive secondary metabolites.

Nozzle Design for Combined Use of MQL and Cryogenic Gas in Machining

Octavio Pereira,Adrián Rodríguez,Joaquín Barreiro,Ana Isabel Fernández-Abia,Luis Norberto López de Lacalle 한국정밀공학회 2017 International Journal of Precision Engineering and Vol.4 No.1

Nowadays, the need for not only technically but also environmentally efficient machining processes is increasing. In this context, the reduction of oil emulsion type coolants used during machining of aeronautical engine components supposes a great challenge. In this paper, a novel approach based on the design, optimization and validation of a nozzle adaptor combining cryogenic technology and minimum quantity lubrication systems is proposed. The proposed work also deals with the aim of obtaining a cost-effective process. Thus, CO2 flow and velocity was optimized in this line. Theoretically-based analysis were performed and compared with computational fluid dynamics (CFD) simulations and with real experimental tests as well. Once optimizing these key factors, two nozzle adaptors were designed and simulated by CFD. Different geometries were tested looking for the most efficient design. Finally, to obtain a feasible industrial product, the developed nozzle was tested as a CryoMQL demonstrator comparing with other lubri-coolant techniques during milling Inconel 718. Results show a successful balance between technical and environmental issues using this technology when milling aeronautical alloys.

Simulation of Cryo-cooling to Improve Super Alloys Cutting Tools

Octavio Pereira,Adrián Rodríguez,Amaia Calleja-Ochoa,Ainhoa Celaya,Luis Norberto López de Lacalle,Asier Fernández-Valdivielso,Haizea González 한국정밀공학회 2022 International Journal of Precision Engineering and Vol.9 No.1

Improve machining processes from an environmental point of view is a hot topic currently. In this line, cryogenics CO 2 is presented as a solution to substitute conventional oil emulsions. However, to be applied industrially, it is needed to control CO 2 flow rate with the aim of reducing CO 2 consumption to reach what it is known as ECO 2 -performance (economy + ecology). Then, despite currently CO 2 cooling technique is used as external coolant, it is needed to improve its use—especially in milling processes—for achieving this goal. In line with this, in this paper is presented the use of CO 2 as tool internal coolant as a solution to optimize its use. For checking its suitability, a study based on computer fluid dynamics with a new cryogenic tool channels design and experimental tests were carried out for analyzing the differences between using CO 2 as internal and external coolant with the aim of improving the use of cryogenic gases during Inconel 718 milling processes. The results show that the use of CO 2 as internal coolant improves the current milling process not only from environmental point of view but also economic and technical, bringing CO 2 cryogenic technology closer to industrial milling conditions.

The Principle of Facticity: Outline for a Theory of Evidence in Arbitration

de Barros, Octavio Fragata Martins The Korean Association of Arbitration Studies 2013 중재연구 Vol.23 No.4

International Arbitration has distinguished itself as a method for dispute resolution that pleases both common and civil law practitioners. It, however, is not free of criticism, especially when fact-finding and evidentiary issues are at play. Perhaps because fact-finding is very closely linked to the culture in which they lie, perhaps because of the lack of a clear evidentiary rules governing international arbitration, a theory of evidence in international arbitration is still far fetched. Through the analysis of the distinctions between dispute resolution systems and the search for truth paradigm, this paper aims to develop and present an outline for the development of a theory of evidence in international arbitration.

Use of automated artificial intelligence to predict the need for orthodontic extractions

Real Alberto Del,Real Octavio Del,Sardina Sebastian,Oyonarte Rodrigo 대한치과교정학회 2022 대한치과교정학회지 Vol.52 No.2

Objective: To develop and explore the usefulness of an artificial intelligence system for the prediction of the need for dental extractions during orthodontic treatments based on gender, model variables, and cephalometric records. Methods: The gender, model variables, and radiographic records of 214 patients were obtained from an anonymized data bank containing 314 cases treated by two experienced orthodontists. The data were processed using an automated machine learning software (Auto-WEKA) and used to predict the need for extractions. Results: By generating and comparing several prediction models, an accuracy of 93.9% was achieved for determining whether extraction is required or not based on the model and radiographic data. When only model variables were used, an accuracy of 87.4% was attained, whereas a 72.7% accuracy was achieved if only cephalometric information was used. Conclusions: The use of an automated machine learning system allows the generation of orthodontic extraction prediction models. The accuracy of the optimal extraction prediction models increases with the combination of model and cephalometric data for the analytical process.

Fabrication of ZnO electroceramics by reaction bonding

Enrique Rocha-Rangel,Octavio Martínez-Urgell,Carlos Gómez-Yánez 한양대학교 세라믹연구소 2006 Journal of Ceramic Processing Research Vol.7 No.3

ZnO ceramics doped with small amounts of Bi2O3, CoO, MnO, Sb2O3 and Cr2O3 offer a great potential as electroceramic materials to be used as protectors to prevent electric surges. In the present communication, the reaction bonded alumina oxide (RBAO) technique is adapted for the production of ZnO-based ceramics by the reaction bonding zinc oxide (RBZnO) process with the idea of achieving the advantages of the RBAO process. Because Zn oxidation occurs between 330 °C and 468 °C, slow heating rates before the Zn melting point (419 °C) is very important in order to obtain the desired ceramic. The need for a fine microstructure of the matrix with many grain boundaries is discussed. ZnO ceramics doped with small amounts of Bi2O3, CoO, MnO, Sb2O3 and Cr2O3 offer a great potential as electroceramic materials to be used as protectors to prevent electric surges. In the present communication, the reaction bonded alumina oxide (RBAO) technique is adapted for the production of ZnO-based ceramics by the reaction bonding zinc oxide (RBZnO) process with the idea of achieving the advantages of the RBAO process. Because Zn oxidation occurs between 330 °C and 468 °C, slow heating rates before the Zn melting point (419 °C) is very important in order to obtain the desired ceramic. The need for a fine microstructure of the matrix with many grain boundaries is discussed.

Induction of fertile estrus without the use of steroid hormones in seasonally anestrous Suffolk ewes

Erika Elizabeth Miguel-Cruz,Octavio Mejia-Villanueva,Luis Zarco 아세아·태평양축산학회 2019 Animal Bioscience Vol.32 No.11

Objective: To evaluate the efficacy of treatments based on gonadotrophin-releasing hormone (GnRH), GnRH-prostaglandin F2α (PGF2α), and/or intense exposure to novel rams to induce fertile estrus without the use of steroid hormones in seasonally anestrous Suffolk ewes. Methods: In the first experiment, ewes were treated with one injection of GnRH, two injections of GnRH administered 7 days apart, or a sequence of GnRH-PGF2α-GnRH (GPG). In the second experiment anestrous ewes were exposed, for 36 days starting on the day of weaning, to groups of four rams of three different breeds that were alternated every day. Besides exposure to the male effect (ME), the ewes were injected with saline solution (ME group, n = 20), with GnRH (ME-GnRH group, n = 20) or with a sequence of GnRH-PGF2α-GnRH (ME-GPG group, n = 20). The rams used for male-effect were fitted with aprons to prevent mating, and ewes detected in estrus were bred to selected fertile rams. Ovarian activity was monitored by progesterone determinations in both experiments. Results: In the first experiment sustained induction of ovarian activity was not achieved and no ewe was detected in estrus. In the second experiment induction of sustained ovarian activity was achieved in all groups. Most of the ewes were detected in estrus, 76.7% of the ewes were mated during a 36-d breeding period and 71.7% of all the ewes became pregnant during that period. No significant differences between groups were found for any of these variables. However, estrus detection efficiency was higher in the ME-GnRH group than in the ME group (p<0.05). Conclusion: An intense male-effect, that included the continuous presence and frequent alternation of several rams of different breeds, was sufficient to induce ovarian activity and fertile estrus in Suffolk ewes during the period of deep anestrus without the use of hormones, although addition of GnRH improved the efficiency of estrus detection.

Control Algorithm for Taking off and Landing Manoeuvres of Quadrotors in Open Navigation Environments

Yair Lozano Hernández,Octavio Gutiérrez Frías,Norma Lozada-Castillo,Alberto Luviano Juárez 제어·로봇·시스템학회 2019 International Journal of Control, Automation, and Vol.17 No.9

This paper presents a control algorithm for the taking off and landing manoeuvres of a quadrotor aircraft in open navigation environments. For this purpose, a combination of controllers based on nested saturations and a generalised proportional integral (GPI) controller is used. The first controller limits both the angular positions and angular velocities in a small compact set, which defines the closed-loop stability domain and guarantees the total convergence of the state, whereas the second is designed for the translational aspect, considering the presence of disturbances during landing. The proposed controller is designed considering the presence of disturbances; therefore, greater robustness is obtained regarding perturbations that may occur in open navigation environments. The algorithm convergence is proven by means of Lyapunov’s second method. Several numerical simulations are presented to demonstrate the effectiveness of our proposed algorithm, and a comparison test against an effective method for indoor environments is provided to illustrate its superior performance.

Numerical simulation and design of a parabolic trough solar collector used as a direct generator in a solar-GAX cooling cycle

Daniel Sauceda,Nicolás Velázquez,Octavio García-Valladares,Ricardo Beltrán 대한기계학회 2011 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.25 No.6

In this work, a solar parabolic trough collector (PTC) has been dimensioned and its technical feasibility has been evaluated in order to be used as ammonia direct vapor generator in an advanced absorption air-cooled Solar-GAX cycle of 10.6 kW cooling capacity. A detailed numerical simulation model that takes into account the geometry and the optical, thermal and fluid dynamic behavior of the PTC has been developed. The model has been solved in order to reach minimal thermal losses through the PTC, and maximum coefficient of performance (COP) of the Solar-GAX cycle. Under design conditions, the solar PTC efficiency, the COP of the Solar-GAX cycle and the global efficiency of the system were 0.62, 0.87 y and 0.54 respectively. The calculated efficiency is 25.5 % higher than that provided by a single effect water-lithium bromide cycle coupled in an indirect form with a solar PTC system.