• Title/Summary/Keyword: Xavier

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Investigating spurious cracking in finite element models for concrete fracture

  • Gustavo Luz Xavier da Costa;Carlos Alberto Caldeira Brant;Magno Teixeira Mota;Rodolfo Giacomim Mendes de Andrade;Eduardo de Moraes Rego Fairbairn;Pierre Rossi
    • Computers and Concrete
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    • v.31 no.2
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    • pp.151-161
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    • 2023
  • This paper presents an investigation of variables that cause spurious cracking in numerical modeling of concrete fracture. Spurious cracks appear due to the approximate nature of numerical modeling. They overestimate the dissipated energy, leading to divergent results with mesh refinement. This paper is limited to quasi-static loading regime, homogeneous models, cracking as the only nonlinear mode of deformation and cracking only due to tensile loading. Under these conditions, some variables that can be related to spurious cracking are: mesh alignment, ductility, crack band width, structure size, mesh refinement and load increment size. Case studies illustrate the effect of each variable and convergence analyses demonstrate that, after all, load-increment size is the most important variable. Theoretically, a sufficiently small load increment is able to eliminate or at least alleviate the detrimental influence of the other variables. Such load-increment size might be prohibitively small, rendering the simulation unfeasible. Hence, this paper proposes two alternatives. First, it is proposed an algorithm that automatically find such small load increment size automatically, which not necessarily avoid large computations. Then, it is proposed a double simulation technique, in which the crack is forced to propagate through the localization zone.

Buyer's Duty to Examine Goods and Notify Seller of Lack of Conformity: Belgian Law Perspective Compared with the CISG and the CESL (매수인의 물품검사 및 계약부적합성 통지의무; CISG 및 CESL과 비교된 벨기에법의 관점에서)

  • Byung-Mun Lee;Hautem Xavier
    • Korea Trade Review
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    • v.45 no.1
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    • pp.83-100
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    • 2020
  • This study aimed to provide the most accurate analysis possible regarding the buyer's duty to examine goods and give notice, or the like, of non-conformity to the seller under Belgian law in comparison with the CISG and CESL. Even though Belgium is the capital of the Europe Union, most of its laws remain untranslated in English. Therefore, this study may offer key insights into the specificities of Belgian law, which while being derived from the French Napoleon Code has its own practices coded into its Case Law. It also makes a comparison with the new CESL and CISG in order to evaluate their respective influence on national law and other infructuous attempts to harmonize Belgian law for the internal European market. Evaluating the differences of each system in the spirit of comparative law may be a good basis for the development of laws in each jurisdiction.

Low complexity ordered successive interference cancelation detection algorithm for uplink MIMO SC-FDMA system

  • Nalamani G. Praveena;Kandasamy Selvaraj;David Judson;Mahalingam Anandaraj
    • ETRI Journal
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    • v.45 no.5
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    • pp.899-909
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    • 2023
  • In mobile communication, the most exploratory technology of fifth generation is massive multiple input multiple output (MIMO). The minimum mean square error and zero forcing based linear detectors are used in multiuser detection for MIMO single-carrier frequency division multiple access (SCFDMA). When the received signal is detected and regularization sequence is joined in the equalization of spectral null amplification, these schemes experience an error performance and the signal detection assesses an inversion of a matrix computation that grows into complexity. Ordered successive interference cancelation (OSIC) detection is considered for MIMO SC-FDMA, which uses a posteriori information to eradicate these problems in a realistic environment. To cancel the interference, sorting is preferred based on signal-to-noise ratio and log-likelihood ratio. The distinctiveness of the methodology is to predict the symbol with the lowest error probability. The proposed work is compared with the existing methods, and simulation results prove that the defined algorithm outperforms conventional detection methods and accomplishes better performance with lower complication.

Development of a Secure Routing Protocol using Game Theory Model in Mobile Ad Hoc Networks

  • Paramasivan, Balasubramanian;Viju Prakash, Maria Johan;Kaliappan, Madasamy
    • Journal of Communications and Networks
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    • v.17 no.1
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    • pp.75-83
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    • 2015
  • In mobile ad-hoc networks (MANETs), nodes are mobile in nature. Collaboration between mobile nodes is more significant in MANETs, which have as their greatest challenges vulnerabilities to various security attacks and an inability to operate securely while preserving its resources and performing secure routing among nodes. Therefore, it is essential to develop an effective secure routing protocol to protect the nodes from anonymous behaviors. Currently, game theory is a tool that analyzes, formulates and solves selfishness issues. It is seldom applied to detect malicious behavior in networks. It deals, instead, with the strategic and rational behavior of each node. In our study,we used the dynamic Bayesian signaling game to analyze the strategy profile for regular and malicious nodes. This game also revealed the best actions of individual strategies for each node. Perfect Bayesian equilibrium (PBE) provides a prominent solution for signaling games to solve incomplete information by combining strategies and payoff of players that constitute equilibrium. Using PBE strategies of nodes are private information of regular and malicious nodes. Regular nodes should be cooperative during routing and update their payoff, while malicious nodes take sophisticated risks by evaluating their risk of being identified to decide when to decline. This approach minimizes the utility of malicious nodes and it motivates better cooperation between nodes by using the reputation system. Regular nodes monitor continuously to evaluate their neighbors using belief updating systems of the Bayes rule.

Papaya: A gifted nutraceutical plant - a critical review of recent human health research

  • Karunamoorthi, Kaliyaperumal;Kim, Hyung-Min;Jegajeevanram, Kaliyaperumal;Xavier, Jerome;Vijayalakshmi, Jayaraman
    • CELLMED
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    • v.4 no.1
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    • pp.2.1-2.17
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    • 2014
  • The plant kingdom is considered to be a repository of modern medicine, attributable to their rich source of bio-active molecules and secondary metabolites. It is indeed the Nutraceuticals that enhance immunity and ensure a healthier life because of their prophylactic and therapeutic values. Over centuries, papaya [Caricaceae; (Carica papaya Linn.)] is a renowned nutritious and medicinal plant. Each part of the papaya like root, stem, leaf, flower, fruit, seed, rinds, and latex has its own nutraceutical properties. It serves as food, cooking aid, and Ethnomedicine to prevent and treat wide-range of diseases and disorders. It has also been traditionally used as appetite enhancer, meat tenderizer, purgative, medicinal acne, abortifacient and vermifuge. Over decades, a series of scientific attempts were made to authenticate the nutraceutical properties of papaya. These studies validated that the papaya has antiplasmodial, antitrichochramal, antitrichomonal, antidengue, and anti-cancer activities. They have also exhibited that papaya possesses antiseptic, antiparasitic, anti-inflammatory, antidiabetic, and contraceptive features, and it helps in the management of sickle-cell anaemia, HIV, heart diseases and digestional disorders too. Nevertheless, the responsible bio-active molecules and their mode of actions remain indistinct and imprecise, and this calls for further pharmacological and clinical research on them. Conclusively, papaya is one of the naturally gifted plants; though its nutraceutical properties as a food or as a quasi-drug are poorly understood or undervalued by people. Accordingly, this scrutiny, demand for instigation of public health awareness campaigns to promote papaya consumption, so that the society shall acquire optimal benefits of papaya and in turn prevent and alleviate various diseases and illness.

Effect of GeO2 on embryo development and photosynthesis in Fucus vesiculosus (Phaeophyceae)

  • Tarakhovskaya, Elena R.;Kang, Eun-Ju;Kim, Kwang-Young;Garbary, David J.
    • ALGAE
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    • v.27 no.2
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    • pp.125-134
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    • 2012
  • Germanium dioxide ($GeO_2$) has been used for many years in the cultivation of red and green algae as a means of controlling the growth of diatoms. Brown algae are sensitive to $GeO_2$, however, the basis of this sensitivity has not been characterized. Here we use embryos of $Fucus$ $vesiculosus$ to investigate morphological and physiological impacts of $GeO_2$ toxicity. Morphometric features of embryos were measured microscopically, and physiological features were determined using pulse amplitude modulated (PAM) fluorometry. At 5 mg $L^{-1}$ $GeO_2$, embryos grew slower than controls and developed growth abnormalities. After 24 h, initial zygote divisions were often oblique rather than transverse. Rhizoids had inflated tips in $GeO_2$ and were less branched, and apical hairs were deformed, with irregularly aligned, spheroidal cells. Minimum fluorescence ($F_0$) showed minor differences over the 10 days experiment, and pigment levels (chlorophylls $a$, $c$ and total carotenoids) showed no difference after 10 days. Optimum quantum yield increased from ca. 0.52 at 24 h to 0.67 at 5 days, and $GeO_2$-treated embryos had higher mean values (significant at 3 and 5 days). Optimum quantum yield of photosystem II (${\Phi}_{PSII}$) was stable in control thalli after 5 days, but declined significantly in $GeO_2$. Addition of silica (as $SiO_2$) did not reverse the effects of $GeO_2$. These results suggest that $GeO_2$ toxicity in brown algae is associated with negative impacts at the cytological level rather than metabolic impacts associated with photosynthesis.

Growth and nutrient uptake by Palmaria palmata integrated with Atlantic halibut in a land-based aquaculture system

  • Corey, Peter;Kim, Jang K.;Duston, Jim;Garbary, David J.
    • ALGAE
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    • v.29 no.1
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    • pp.35-45
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    • 2014
  • Palmaria palmata was integrated with Atlantic halibut Hippoglossus hippoglossus on a commercial farm for one year starting in November, with a temperature range of 0.4 to $19.1^{\circ}C$. The seaweed was grown in nine plastic mesh cages (each $1.25m^3$ volume) suspended in a concrete sump tank ($46m^3$) in each of three recirculating systems. Two tanks received effluent water from tanks stocked with halibut, and the third received ambient seawater serving as a control. Thalli were tumbled by continuous aeration, and held under a constant photoperiod of 16 : 8 (L : D). Palmaria stocking density was $2.95kg\;m^{-3}$ initially, increasing to $9.85kg\;m^{-3}$ after a year. Specific growth rate was highest from April to June (8.0 to $9.0^{\circ}C$), 1.1% $d^{-1}$ in the halibut effluent and 0.8% $d^{-1}$ in the control, but declined to zero or less than zero above $14^{\circ}C$. Total tissue nitrogen of Palmaria in effluent water was 4.2 to 4.4% DW from January to October, whereas tissue N in the control system declined to 3.0-3.6% DW from April to October. Tissue carbon was independent of seawater source at 39.9% DW. Estimated tank space required by Palmaria for 50% removal of the nitrogen excreted by 100 t of halibut during winter is about 29,000 to $38,000m^2$, ten times the area required for halibut culture. Fifty percent removal of carbon from the same system requires 7,200 to $9,800m^2$ cultivation area. Integration of P. palmata with Atlantic halibut is feasible below $10^{\circ}C$, but is impractical during summer months due to disintegration of thalli associated with reproductive maturation.

Screening on Receptor Tyrosine Kinase Inhibitory Activity of Marine Algae-Derived Symbiotic Microorganisms (해조류 공생미생물의 Receptor Tyrosine Kinase 억제효능 검색)

  • Yun, Keum-Ja;Yang, Guohua;Feng, Zhile;Nenkep, Viviane N.;Xavier, Siwe-Noundou;Leutou, Alain S.;Kim, Gun-Do;Cho, Hee-Yeong;Choi, Hong-Dae;Son, Byeng-Wha
    • Korean Journal of Pharmacognosy
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    • v.41 no.1
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    • pp.43-47
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    • 2010
  • In order to screen new receptor tyrosine kinase inhibitor which is expected to be anticancer drug lead, we have investigated receptor tyrosine kinase inhibitory activity on the marine alga-derived symbiotic microorganisms (500 strains). The significant activities (over 70% inhibition at $10\;{\mu}g/ml$) were observed in the extracts of ten strains (Strain No.: MFA018, 019, 206, 242, 325, 335, 343, 344, 354, 356), isolated from marine red algae, five strains (Strain No.: MFA030, 126, 213, 324, 339), isolated from the brown algae, and one strain (Strain No.: MFA272), isolated from the marine green algae, respectively. Among the active strains, MFA019 and 356 showed strong receptor tyrosine kinase inhibitory activity with $IC_{50}$ values of 0.6 and $0.9\;{\mu}g/ml$, respectively.

Effects of Substituting Soybean Meal for Sunflower Cake in the Diet on the Growth and Carcass Traits of Crossbred Boer Goat Kids

  • Palmieri, Adriana Dantas;Oliveira, Ronaldo Lopes;Ribeiro, Claudio Vaz Di Mambro;Ribeiro, Marinaldo Divino;Ribeiro, Rebeca Dantas Xavier;Leao, Andre Gustavo;Agy, Mariza Sufiana Faharodine Aly;Ribeiro, Ossival Lolato
    • Asian-Australasian Journal of Animal Sciences
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    • v.25 no.1
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    • pp.59-65
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    • 2012
  • The present study was conducted to determine the best level of substitution of soybean meal by sunflower cake in diets for kids through the evaluation of quantitative carcass traits. Thirty-two Boer kids X 1/2 NDB (no defined breed), males, non-castrated, with 4 months of age and initial body weight of $15{\pm}3.2$ kg, were randomly assigned to individual pens. The treatments contained four substitution levels of soybean meal by sunflower cake (0, 33, 66 and 100% DM). At the end of the experimental period, the animals were slaughtered. There was no influence of the treatments on any of the mean values of the evaluated measures (p>0.05): 21.78 kg (body weight at slaughter), 8.65 kg (hot carcass weight), 8.59 kg (cold carcass weight), 40.27% (hot carcass yield), 39.20% (cold carcass yield), 7.73 $cm^2$ (rib eye area), 46.74 cm (carcass outer length), 45.68 cm (carcass internal length), 36.92 cm (leg length), 26.04 cm (leg perimeter), 48.66 cm (hind perimeter), 58.62 cm (thoracic perimeter), 0.20 (carcass compactness index), 68.48% (total muscle of the leg), 2.79% (total leg fat), 55.19% (subcutaneous leg fat), 28.82% (total bone), 81.66 g (femur weight), 14.88 cm (femur length), 0.38 (leg muscularity index), 2.53 (muscle:bone ratio) and 33.42 (muscle:fat ratio). The substitution of soybean meal by sunflower cake may be recommended up to a level of 100% without alterations to quantitative carcass traits.

In Vitro Screening for Antimicrobial Activity of Chitosans and Chitooligosaccharides, Aiming at Potential Uses in Functional Textiles

  • Fernandes, Joao C.;Tavaria, Freni K.;Fonseca, Susana C.;Ramos, Oscar S.;Pintado, Manuela E.;Malcata, F. Xavier
    • Journal of Microbiology and Biotechnology
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    • v.20 no.2
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    • pp.311-318
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    • 2010
  • Antimicrobial finishing of textiles has been found to be an economical way to prevent (or treat) skin disorders. Hence, this research effort was aimed at elucidating the relationship between the molecular weight (MW) of chitosan and its antimicrobial activity upon six dermal reference microorganisms, as well as the influence of the interactions with cotton fabrics on said activity. Using 3 chitosans with different MWs, as well as two chitooligosaccharide (COS) mixtures, a relevant antimicrobial effect was observed by 24 h for the six microorganisms tested; it was apparent that the antimicrobial effect is strongly dependent on the type of target microorganism and on the MW of chitosan - being higher for lower MW in the case of E. coli, K. pneumoniae, and P. aeruginosa, and the reverse in the case of both Gram-positive bacteria. Furthermore, a strong antifungal effect was detectable upon C. albicans, resembling the action over Gram-positive bacteria. Interactions with cotton fabric resulted in a loss of COS activity when compared with cultured media, relative to the effect over Gram-negative bacteria. However, no significant differences for the efficacy of all the 5 compounds were observed by 4 h. The three chitosans possessed a higher antimicrobial activity when impregnated onto the fabric, and presented a similar effect on both Gram-positive bacteria and yeast, in either matrix. Pseudomonas aeruginosa showed to be the most resistant microorganism to all five compounds.