Integration of Forming Operations on Hybrid Additive Manufacturing Systems Based on Fusion Welding

João P. M. Pragana,Valentino A. M. Cristino,Ivo M. F. Bragança,Carlos M. A. Silva,Paulo A. F. Martins 한국정밀공학회 2020 International Journal of Precision Engineering and Vol.7 No.3

This paper is focused on the integration of metal forming operations in hybrid systems that combine additive manufacturing (AM) by gas metal wire arc and subtractive manufacturing by machining. The investigation is carried out in AISI 316L stainless steel wire and draws from tensile testing to incremental sheet forming of truncated conical shapes. Commercial sheets from the same material are utilized for comparison purposes. Thickness measurements, digital image correlation (DIC), circle grid analysis (CGA) and microstructural and scanning electron microscopy (SEM) observations are carried out to understand how diff erent is the mechanical behaviour of the deposited metal from that of commercial metal sheets and how signifi cant is the infl uence of the deposited metal microstructure on its overall formability. Results confi rm that integration of metal forming operations in hybrid AM routes is feasible despite the formability of deposited metal being smaller than that of the commercial metal sheets due to the strong anisotropy induced by the dendritic based microstructure of the deposited metal. Incremental forming of two deposited parts also allows concluding that integration of metal forming operations in hybrid AM systems is a step towards green and sustainable manufacturing by extending their fi eld of applicability to the fabrication of complex ready-to-use parts requiring combination of diff erent processes.

Hybrid Wire-Arc Additive Manufacturing of Conformal Cooling Channels: A Feasibility Study

João P. M. Pragana,Ivo M. F. Bragança,Carlos M. A. Silva,Paulo A. F. Martins 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.10 No.1

This paper investigates the feasibility of hybridizing wire-arc additive manufacturing with metal forming to create conformal cooling channels in moulds for hot material processing. An axisymmetric mould is used as a prototype test case and plastic deformation by flaring of the additively deposited inner tubular element is utilized to create the overhangs for connecting with the outer tubular element that are needed to fabricate the cooling channels. Finite element modelling of plastic deformation by flaring of the additively deposited material is carried out to identify the different modes of deformation and to determine the maximum allowable radius of the overhangs. Results show that the proposed hybridization of wire-arc additive manufacturing with plastic deformation by flaring adds flexibility to the design and fabrication of conformal channels in the as-built mould by eliminating the use of support structures and avoiding the use of complex deposition strategies. Finishing of the functional surfaces of the as-built mould by turning ensures the required accuracy and surface quality.

The role of interfacial elasticity on the rheological behavior of polymer blends

Jorge M. Silva,Ana V. Machado,Paula Moldenaers,João M. Maia 한국유변학회 2010 Korea-Australia rheology journal Vol.22 No.1

In this work, the influence of interfacial modification on the rheological behavior of polymer blends was investigated. First, commercial blends of polyamide-6 and ethylene-propylene copolymer, PA6/EPM, noncompatibilized and compatibilized with EPM grafted with maleic anhydride, with high viscosity and elasticity ratios were studied. The observation of the morphology frozen during extension tests seemed to indicate that the droplets of the highly compatibilized blends are slightly deformed unlike those of the noncompatibilized ones. Stress relaxation experiments, both in shear and extension, showed that the introduction of the compatibilizer leads to the appearance of a second very long relaxation mechanism, the question then being what is its cause. In order to better understand the relative importance of relaxation of the droplets and relaxation of the interfaces in this kind of compatibilized blends, model high viscosity ratio blends of optically transparent materials, in this case poly(methylmethacrylate), PMMA, polystyrene, PS,and oxazoline-modified polystyrene, PSOX were prepared. This allows Small Angle Light Scattering (SALS) to be used in dilute blends to complement the rheometrical characterization and thus evaluate the deformation of the droplets in transient shear flows. In these blends there is also an additional longer relaxation time present but no changes in the morphology can be readily observed. In addition, the blend with functionalized PS shows a droplet deformation in the vorticity direction, which is an indication of an increase in the elasticity of the interface. Thus, our findings seem to indicate that the main factor behind the increase in relaxation time stress relaxation at and in the interfaces and not droplet deformation and recovery. The role of the elasticity of the interface became quite clear when PP/EVOH blends, non-compatibilized and compatibilized with Na+ were tested. In this case the elasticity of the interface is negligible and it was observed that the compatibilization does not alter significantly the relaxation behavior after a step deformation.

Genetics components of rice root architecture and carbon isotopic fractionation parameters: a tracer for breeding in a water-saving irrigation management

Brito Giovani G.,Concenço Germani,Costa Vladimir E.,Fagundes Paulo Ricardo R.,da Silva-Filho João Luis,Parfitt José Maria B.,Magalhães Ariano,Silva Giovana T.,Jardim Thaís M.,Luccas Nathália Furtado,S 한국작물학회 2022 Journal of crop science and biotechnology Vol.25 No.1

Phenotyping is the major bottleneck in the efort to develop varieties of rice (Oryza sativa L.) suitable for growing under a water-saving irrigation management, such as alternate wetting and drying irrigation techniques (AWD). To analyze if the genotypic variability for carbon isotope discrimination (CID) in rice leaves could be used as a relatively high-throughput tracer to early select superior genotypes highlighting improved root architecture traits when submitted to AWD, a set of twenty varieties grown under semi-natural conditions were submitted to two water irrigation regimes, continuous fooding (CF) and AWD cycles. Coefcients of genetic variance (π2g) obtained for root architecture, micro-morphological and physiological traits were signifcant for all of them regardless of the adopted irrigation system, except to mean root diameter. The three signifcant principal components (PCs) with eigenvalue>1, explain most of the total variation across cycles and water regimes. For most of analyzed traits, the values of heritability coefcients were higher regardless of adopted irrigation management and trait category; for CID, the magnitudes of broad heritability at an individual level (greater than 0.80) were similar in the two irrigation techniques, evidencing that the success of the selection is independent of irrigation management. The higher CID values after three AWD cycles are associated with varieties with higher total root length and volume. To our knowledge, this is the frst study demonstrating the potential application of CID as a tracer to select root architecture traits in rice when water-saving irrigation management is of concern

From powder to extrudate zeolite-based bifunctional hydroisomerization catalysts: on preserving zeolite integrity and optimizing Pt location

Pedro S. F. Mendes,João M. Silva,M. Filipa Ribeiro,Antoine Daudin,Christophe Bouchy 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.62 No.-

The development of zeolite-based hydroisomerization catalysts in the powder form is widely spread in scientific literature but shaped bodies are the ones being employed in industry. This work aims at bridging that gap. The shaping procedure for HUSY zeolite in presence of an alumina binder disclosed herein achieved a full conservation of zeolite properties, e.g. porosity and Brønsted acidity. When Pt was located inside the zeolite and an homogeneous Pt distribution along the extrudate was ensured, shaped Pt-containing catalysts had similar hydroisomerization performances to those of powder Pt/zeolite in terms of turnover frequency per Brønsted acid site and maximal feed isomers yield. Conversely, non-uniform distribution of Pt along the extrudates diameter (millimetric scale) was observed to reduce the feed isomers yield. This was tentatively explained by the lower local metal to acid sites ratio in the core of the extrudates. Optimal performance of shaped bifunctional catalysts requires, hence, an adequate metal to acid sites ratio throughout the whole catalyst (i.e. at millimetric and nanometric scale), even if full intimacy between catalytic functions is ensured at the nanoscale by the selective deposition of Pt inside the zeolite.

Distinct deep subsurface microbial communities in two sandstone units separated by a mudstone layer

Adriana Giongo,Taiana Haag,Renata Medina-Silva,Roberto Heemann,Leandro M. Pereira,Priscilla M. Zamberlan,Fernanda P. Valdez,Rafael R. Oliveira,Eduardo Eizirik,Adriano R. Viana,João Marcelo M. Ketzer 한국지질과학협의회 2020 Geosciences Journal Vol.24 No.3

Deep subsurface microbial communities are more abundant in coarse-grained sedimentary rocks such as sandstones than in fine-grained mudstones. The low porosity and low permeability of mudstones are believed to restrict microbial life. Then, it is expected that distinct, isolated microbial communities may form in sandstones separated by mudstones. In this context, the connectivity between microbial communities in different sandstone units can be investigated to infer evolutionary patterns of diversification in space-time, which may potentially contribute with relevant data for analyses of hydraulic connectivity and stratigraphic correlation. In this work, we used high throughput DNA sequencing of a ribosomal 16S gene fragment to characterize the prokaryotic communities found in Permian sandstone samples of the same core that are separated by one mudstone interval, in the Charqueadas coal field, Parana Basin (Southern Brazil). Our samples were collected at ~300 m deep, in porous sandstones separated by a thick mudstone package. Differences in the bacterial community structure between samples were observed for the classified OTUs, from phylum to genus. Molecular biology might be further applied as a possible tool to help to understand the spatial and temporal distribution of depositional facies, and the efficiency of low permeability rocks to compartmentalize reservoirs. Ongoing studies aim to extend the present investigation into further analyses regarding lateral changes in microbial communities present in the same sandstone units.

Intraoperative discomfort associated with the use of a rotary or reciprocating system: a prospective randomized clinical trial

Aline Cristine Gomes,Adriana Jesus Soares,Erick M Souza,Alexandre Augusto Zaia,Emmanuel João Nogueira Leal Silva 대한치과보존학회 2017 Restorative Dentistry & Endodontics Vol.42 No.2

Objectives: The aim of this randomized, controlled, prospective clinical study was to evaluate patients’ intraoperative discomfort during root canal preparations in which either multi-file rotary (Mtwo) or single-file reciprocating (Reciproc) systems were used. Materials and Methods: Fifty-five adult patients, aged between 25 and 69 years old, with irreversible pulpitis or pulp necrosis participated in this study. Either the mesiobuccal or the distobuccal canals for maxillary molars and either the mesiobuccal or the mesiolingual canals for mandibular molars were randomly chosen to be instrumented with Mtwo multi-file rotary or Reciproc single-file reciprocating systems. Immediately after each canal instrumentation under anesthesia, patient discomfort was assessed using a 1 - 10 visual analog scale (VAS), ranging from ‘least possible discomfort’ (1) to ‘greatest possible discomfort’ (10). The Wilcoxon signed-rank test was used to determine significant differences at p < 0.05. Results: Little intraoperative discomfort was found in all cases. No statistically significant differences in intraoperative discomfort between the 2 systems were found (p = 0.660). Conclusions: Root canal preparation with multi-file rotary or single-file reciprocating systems had similar and minimal effects on patients’ intraoperative discomfort.

Short-term combined exercise training improves cardiorespiratory fitness and autonomic modulation in cancer patients receiving adjuvant therapy

Cristiano Mostarda,Jurema Castro-Filha,Andréa Dias Reis,Mário Sevílio Jr,Carlos José Dias,Antonio Carlos Silva-Filho,João Batista Silva Garcia,Maria do Desterro Nascimento,Hélio José Coelho-Junior,Bru 한국운동재활학회 2017 JER Vol.13 No.5

Unilateral and Immediate Stimulation of Acupuncture Points Xiaohai (SI8) and Jianwaishu (SI14) of the Small Intestine Meridian Increases Electromyographic Activity and Strength in the Ipsilateral and Contralateral Upper Trapezius Muscle

Leandro L. de Souza,Fernanda L.B. de Araujo,Fernanda A.M. da Silva,Thaís S. Mucciaroni,João E. de Araujo 사단법인약침학회 2016 Journal of Acupuncture & Meridian Studies Vol.9 No.5

We previously showed that a yin meridian of the upper limb decreased electromyographic activity (root mean square) and muscle strength ipsilateral and contralateral to the side of stimulation. Here, we tested the upper trapezius (UT) muscle response after stimulation of a yang meridian of the upper limb, the small intestine (SI). Thirty-eight healthy volunteers were randomized into the following groups: UT muscle (SI14), distant of the UT muscle (SI8), without stimulation (CG), and sham (R3). An acupuncturist certificated by the Brazilian Society of Physical Therapists and Acupuncturists performed the needle insertion. Each volunteer received only one stimulation to the right upper limb. The evaluation occurred before, 5 minutes after, and 20 minutes after needle withdrawal. The root mean square activity increased on the right side in the UT muscle for the SI8 and SI14 groups (F3,37 = 4.67; p < 0.025) at the 20-minute evaluation. The most vigorous response occurred on the contralateral side because the effects were maintained for 5 minutes after withdrawal (F3,37 = 4.52; p < 0.025). Both groups showed an increase in the UT muscle strength at the 20-minute evaluation (F3,37 = 3.41;p < 0.025). The CG and R3 groups did not show any changes. Our data indicate that SI a yang meridian increases the UT muscle response.

Antinociceptive Action and Redox Properties of Citronellal, an Essential Oil Present in Lemongrass

Lucindo Quintans-Júnior,Ricardo Fagundes da Rocha,Fernanda Freitas Caregnato,José Claudio Fonseca Moreira,Francilene Amaral da Silva,Adriano Antunes de Souza Araújo,João Paulo Almeida dos Santos,Mônic 한국식품영양과학회 2011 Journal of medicinal food Vol.14 No.6

Citronellal (CT) is a monoterpenoid and the major constituent of the mixture of terpenoids that give the citronella oil its lemon scent. Citronella oil is widely used around the world for various purposes and is mainly obtained from plants of the Cymbopogon genus, which are known as “lemongrass.” Considering these plants have been used worldwide for various medicinal purposes, the interest of researchers to understand the biological activities of monoterpenoids related to the Cymbopogon genus has been increasing. In the present work, we investigated the antinociceptive action and the redox properties of CT. Our results indicate that intraperitoneal injection of CT was effective in reducing nociceptive face-rubbing behavior in both phases of the formalin test, which was also naloxone-sensitive. CT also evoked antinociceptive response in the capsaicin and glutamate tests. The total radical-trapping antioxidant parameter and total antioxidant reactivity assays indicate that CT at doses of 0.1 and 1 mg/mL exerts a significant antioxidant activity, which is probably related to its ability to scavenge superoxide and nitric oxide, but not H_2O_2 or hydroxyl radicals, as evaluated separately by specific in vitro tests. These results show for the first time the antinociceptive potential of CT and indicate that the antioxidant properties of this compound may rely on its mechanism of biological actions because CT-containing natural products are used to treat various diseases related to oxidative stress and reactive species.