• Title/Summary/Keyword: Zagreb

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EXTREMAL CHEMICAL TREES WITH RESPECT TO HYPER-ZAGREB INDEX

  • Ghalavand, Ali;Ashrafi, Ali Reza;Sharafdini, Reza;Ori, Ottorino
    • The Pure and Applied Mathematics
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    • v.26 no.3
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    • pp.177-188
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    • 2019
  • Suppose G is a molecular graph with edge set E(G). The hyper-Zagreb index of G is defined as $HM(G)={\sum}_{uv{\in}E(G)}[deg_G(u)+deg_G(v)]^2$, where $deg_G(u)$ is the degree of a vertex u in G. In this paper, all chemical trees of order $n{\geq}12$ with the first twenty smallest hyper-Zagreb index are characterized.

UPHILL ZAGREB INDICES OF SOME GRAPH OPERATIONS FOR CERTAIN GRAPHS

  • SALEH, ANWAR;BAZHEAR, SARA;MUTHANA, NAJAT
    • Journal of applied mathematics & informatics
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    • v.40 no.5_6
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    • pp.959-977
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    • 2022
  • The topological indices are numerical parameters which determined the biological, physical and chemical properties based on the structure of the chemical compounds. One of the recently topological indices is the uphill Zagreb indices. In this paper, the formulae of some uphill Zagreb indices for a few graph operations of some graphs have been derived. Furthermore, the precise formulae of those indices for the honeycomb network have been found along with their graphical profiles.

ON THE TOPOLOGICAL INDICES OF ZERO DIVISOR GRAPHS OF SOME COMMUTATIVE RINGS

  • FARIZ MAULANA;MUHAMMAD ZULFIKAR ADITYA;ERMA SUWASTIKA;INTAN MUCHTADI-ALAMSYAH;NUR IDAYU ALIMON;NOR HANIZA SARMIN
    • Journal of applied mathematics & informatics
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    • v.42 no.3
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    • pp.663-680
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    • 2024
  • The zero divisor graph is the most basic way of representing an algebraic structure as a graph. For any commutative ring R, each element is a vertex on the zero divisor graph and two vertices are defined as adjacent if and only if the product of those vertices equals zero. In this research, we determine some topological indices such as the Wiener index, the edge-Wiener index, the hyper-Wiener index, the Harary index, the first Zagreb index, the second Zagreb index, and the Gutman index of zero divisor graph of integers modulo prime power and its direct product.

Genetic Transformation of the Yeast Dekkera/Brettanomyces bruxellensis with Non-Homologous DNA

  • Miklenic, Marina;Stafa, Anamarija;Bajic, Ana;Zunar, Bojan;Lisnic, Berislav;Svetec, Ivan-Kresimir
    • Journal of Microbiology and Biotechnology
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    • v.23 no.5
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    • pp.674-680
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    • 2013
  • Yeast Dekkera/Brettanomyces bruxellensis is probably the most common contaminant in wineries and ethanol production processes. The considerable economic losses caused by this yeast, but also its ability to produce and tolerate high ethanol concentrations, make it an attractive subject for research with potential for industrial applications. Unfortunately, efforts to understand the biology of D. bruxellensis and facilitate its broader use in industry are hampered by the lack of adequate procedures for delivery of exogenous DNA into this organism. Here we describe the development of transformation protocols (spheroplast transformation, LiAc/PEG method, and electroporation) and report the first genetic transformation of yeast D. bruxellensis. A linear heterologous DNA fragment carrying the kanMX4 sequence was used for transformation, which allowed transformants to be selected on plates containing geneticin. We found the spheroplast transformation method using 1M sorbitol as osmotic stabilizer to be inappropriate because sorbitol strikingly decreases the plating efficiency of both D. bruxellensis spheroplast and intact cells. However, we managed to modify the LiAc/PEG transformation method and electroporation to accommodate D. bruxellensis transformation, achieving efficiencies of 0.6-16 and 10-20 transformants/${\mu}g$ DNA, respectively. The stability of the transformants ranged from 93.6% to 100%. All putative transformants were analyzed by Southern blot using the kanMX4 sequence as a hybridization probe, which confirmed that the transforming DNA fragment had integrated into the genome. The results of the molecular analysis were consistent with the expected illegitimate integration of a heterologous transforming fragment.

Dual EKF-Based State and Parameter Estimator for a LiFePO4 Battery Cell

  • Pavkovic, Danijel;Krznar, Matija;Komljenovic, Ante;Hrgetic, Mario;Zorc, Davor
    • Journal of Power Electronics
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    • v.17 no.2
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    • pp.398-410
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    • 2017
  • This work presents the design of a dual extended Kalman filter (EKF) as a state/parameter estimator suitable for adaptive state-of-charge (SoC) estimation of an automotive lithium-iron-phosphate ($LiFePO_4$) cell. The design of both estimators is based on an experimentally identified, lumped-parameter equivalent battery electrical circuit model. In the proposed estimation scheme, the parameter estimator has been used to adapt the SoC EKF-based estimator, which may be sensitive to nonlinear map errors of battery parameters. A suitable weighting scheme has also been proposed to achieve a smooth transition between the parameter estimator-based adaptation and internal model within the SoC estimator. The effectiveness of the proposed SoC and parameter estimators, as well as the combined dual estimator, has been verified through computer simulations on the developed battery model subject to New European Driving Cycle (NEDC) related operating regimes.

Integrated Hydrolyzation and Fermentation of Sugar Beet Pulp to Bioethanol

  • Rezic, Tonic;Oros, Damir;Markovic, Iva;Kracher, Daniel;Ludwig, Roland;Santek, Bozidar
    • Journal of Microbiology and Biotechnology
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    • v.23 no.9
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    • pp.1244-1252
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    • 2013
  • Sugar beet pulp is an abundant industrial waste material that holds a great potential for bioethanol production owing to its high content of cellulose, hemicelluloses, and pectin. Its structural and chemical robustness limits the yield of fermentable sugars obtained by hydrolyzation and represents the main bottleneck for bioethanol production. Physical (ultrasound and thermal) pretreatment methods were tested and combined with enzymatic hydrolysis by cellulase and pectinase to evaluate the most efficient strategy. The optimized hydrolysis process was combined with a fermentation step using a Saccharomyces cerevisiae strain for ethanol production in a single-tank bioreactor. Optimal sugar beet pulp conversion was achieved at a concentration of 60 g/l (39% of dry weight) and a bioreactor stirrer speed of 960 rpm. The maximum ethanol yield was 0.1 g ethanol/g of dry weight (0.25 g ethanol/g total sugar content), the efficiency of ethanol production was 49%, and the productivity of the bioprocess was 0.29 $g/l{\cdot}h$, respectively.

Global hydroelastic analysis of ultra large container ships by improved beam structural model

  • Senjanovic, Ivo;Vladimir, Nikola;Tomic, Marko;Hadzic, Neven;Malenica, Sime
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.6 no.4
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    • pp.1041-1063
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    • 2014
  • Some results on the hydroelasticity of ultra large container ships related to the beam structural model and restoring stiffness achieved within EU FP7 Project TULCS are summarized. An advanced thin-walled girder theory based on the modified Timoshenko beam theory for flexural vibrations with analogical extension to the torsional problem, is used for formulation of the beam finite element for analysis of coupled horizontal and torsional ship hull vibrations. Special attention is paid to the contribution of transverse bulkheads to the open hull stiffness, as well as to the reduced stiffness of the relatively short engine room structure. In addition two definitions of the restoring stiffness are considered: consistent one, which includes hydrostatic and gravity properties, and unified one with geometric stiffness as structural contribution via calm water stress field. Both formulations are worked out by employing the finite element concept. Complete hydroelastic response of a ULCS is performed by coupling 1D structural model and 3D hydrodynamic model as well as for 3D structural and 3D hydrodynamic model. Also, fatigue of structural elements exposed to high stress concentration is considered.

Comparison of shear bond strengths of different types of denture teeth to different denture base resins

  • Prpic, Vladimir;Schauperl, Zdravko;Glavina, Domagoj;Catic, Amir;Cimic, Samir
    • The Journal of Advanced Prosthodontics
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    • v.12 no.6
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    • pp.376-382
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    • 2020
  • PURPOSE. To determine the shear bond strengths of different denture base resins to different types of prefabricated teeth (acrylic, nanohybrid composite, and cross-linked) and denture teeth produced by computer-aided design/computer-aided manufacturing (CAD/CAM) technology. MATERIALS AND METHODS. Prefabricated teeth and CAD/CAM (milled) denture teeth were divided into 10 groups and bonded to different denture base materials. Groups 1-3 comprised of different types of prefabricated teeth and cold-polymerized denture base resin; groups 4-6 comprised of different types of prefabricated teeth and heat-polymerized denture base resin; groups 7-9 comprised of different types of prefabricated teeth and CAD/CAM (milled) denture base resin; and group 10 comprised of milled denture teeth produced by CAD/CAM technology and CAD/CAM (milled) denture base resin. A universal testing machine was used to evaluate the shear bond strength for all specimens. One-way ANOVA and Tukey post-hoc test were used for analyzing the data (α=.05). RESULTS. The shear bond strengths of different groups ranged from 3.37 ± 2.14 MPa to 18.10 ± 2.68 MPa. Statistical analysis showed significant differences among the tested groups (P<.0001). Among different polymerization methods, the lowest values were determined in cold-polymerized resin.There was no significant difference between the shear bond strength values of heat-polymerized and CAD/CAM (milled) denture base resins. CONCLUSION. Different combinations of materials for removable denture base and denture teeth can affect their bond strength. Cold-polymerized resin should be avoided for attaching prefabricated teeth to a denture base. CAD/CAM (milled) and heat-polymerized denture base resins bonded to different types of prefabricated teeth show similar shear bond strength values.

REMARKS ON THE INNER POWER OF GRAPHS

  • JAFARI, S.;ASHRAFI, A.R.;FATH-TABAR, G.H.;TAVAKOLI, Mostafa
    • Journal of applied mathematics & informatics
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    • v.35 no.1_2
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    • pp.25-32
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    • 2017
  • Let G be a graph and k is a positive integer. Hammack and Livesay in [The inner power of a graph, Ars Math. Contemp., 3 (2010), no. 2, 193-199] introduced a new graph operation $G^{(k)}$, called the $k^{th}$ inner power of G. In this paper, it is proved that if G is bipartite then $G^{(2)}$ has exactly three components such that one of them is bipartite and two others are isomorphic. As a consequence the edge frustration index of $G^{(2)}$ is computed based on the same values as for the original graph G. We also compute the first and second Zagreb indices and coindices of $G^{(2)}$.

Undergraduate Power Electronics Laboratory - Applying TSMST Method

  • Jakopovic, Zeljko;Sunde, Viktor;Benci, Zvonko
    • Journal of Power Electronics
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    • v.10 no.6
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    • pp.621-627
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    • 2010
  • This paper presents a TSMST (Theory - Simulation - Measurement - Simulation - Theory) method for power electronics laboratory. The method successfully integrates theory, simulation and measurement, thus enabling better integration of student's knowledge and better usage of inadequate number of laboratory hours. Students are attracted with relatively simple tasks to be solved and modern, but economical laboratory equipment. A significant part of the assignments can be made at home, thus lowering the pressure on students to finish the tasks on time. The proposed method is described on three basic examples explaining characteristic phases of the TSMST method.