CFD and surrogates-based inducer optimization

Toma? Kratky,Luka? Zavadil,Vit Doubrava 한국유체기계학회 2016 International journal of fluid machinery and syste Vol.9 No.3

Due to the nature of cavitation numerical analyses, computational optimization of a pump with respect to the cavitation properties is extremely demanding. In this paper it is shown how a combination of Transient Blade Row (TBR) method and some simplifications can be used for making the optimization process more efficient and thus possible on current generation of hardware. The aim of the paper is not the theory of hydraulic design. Instead, the practical aspects of numerical optimization are shown. This is done on an example of a radial pump and a combination of ANSYS CFX, ANSYS software tools and custom scripts is used. First, a comparison of TBR and fully-transient simulation is made. Based on the results, the TBR method is chosen and a parametric model assembled. Design of Experiment (DOE) table is computed and the results are used for sensitivity analysis. As the last step, the final design is created and computed as fully-transient. In conclusion, the results are discussed.

MINLP optimization of a composite I beam floor system

Tomaž Žula,Stojan Kravanja,Uroš Klanšek 국제구조공학회 2016 Steel and Composite Structures, An International J Vol.22 No.5

This paper presents the cost optimization of a composite I beam floor system, designed to be made from a reinforced concrete slab and steel I sections. The optimization was performed by the mixed-integer non-linear programming (MINLP) approach. For this purpose, a number of different optimization models were developed that enable different design possibilities such as welded or standard steel I sections, plastic or elastic cross-section resistances, and different positions of the neutral axes. An accurate economic objective function of the selfmanufacturing costs was developed and subjected to design, resistance and deflection (in)equality constraints. Dimensioning constraints were defined in accordance with Eurocode 4. The Modified Outer-Approximation/ Equality-Relaxation (OA/ER) algorithm was applied together with a two-phase MINLP strategy. A numerical example of the optimization of a composite I beam floor system, as presented at the end of this paper, demonstrates the applicability of the proposed approach. The optimal result includes the minimal produced costs of the structure, the optimal concrete and steel strengths, and dimensions.

Non-linear analysis of side-plated RC beams considering longitudinal and transversal interlayer slips

Jerneja Kolšek,Tomaž Hozjan,Aleš Kroflič,Igor Planinc,Miran Saje 국제구조공학회 2014 Steel and Composite Structures, An International J Vol.16 No.6

A new mathematical model and its finite element formulation for the non-linear stress-strain analysis of a planar beam strengthened with plates bolted or adhesively bonded to its lateral sides is presented. The connection between the layers is considered to be flexible in both the longitudinal and the transversal direction. The following assumptions are also adopted in the model: for each layer (i.e., the beam and the side plates) the geometrically linear and materially non-linear Bernoulli's beam theory is assumed, all of the layers are made of different homogeneous non-linear materials, the debonding of the beam from the side-plates due to, for example, a local buckling of the side plate, is prevented. The suitability of the theory is verified by the comparison of the present numerical results with experimental and numerical results from literature. The mechanical response arising from the theoretical model and its numerical formulation has been found realistic and the numerical model has been proven to be reliable and computationally effective. Finally, the present formulation is employed in the analysis of the effects of two different realizations of strengthening of a characteristic simply supported flexural beam (plates on the sides of the beam versus the tension-face plates). The analysis reveals that side plates efficiently enhance the bearing capacity of the flexural beam and can, in some cases, outperform the tensile-face plates in a lower loss of ductility, especially, if the connection between the beam and the side plates is sufficiently stiff.

Description of a novel pectin-degrading bacterial species Prevotella pectinovora sp. nov., based on its phenotypic and genomic traits

Brigita Nograšek,Tomaž Accetto,Lijana Fanedl,Gorazd Avguštin 한국미생물학회 2015 The journal of microbiology Vol.53 No.8

Five strictly anaerobic Gram-negative bacterial strains, P4-65, P4-76T, P5-60, P5-119, and P5-125, presumably belonging to the genus Prevotella were isolated from pig fecal samples. Strains were tested for various phenotypic traits and nearcomplete genome sequences were obtained and analyzed. Phylogenetic analysis based on 16S rRNA gene sequences and multilocus sequence analysis based on five conserved genes confirmed that the strains belong to the genus Prevotella, revealing that they represent a novel and discrete lineage distinct from other known species of this genus. The size of the genome of the isolated strains is 3–3.3 Mbp, and the DNA G+C content is 47.5–48.1 mol%. The isolates are strictly anaerobic, rod-shaped with rounded ends, non-motile and non-spore-forming. The main fermentation products are succinate and acetate, with minor concentrations of isovalerate, propionate and isobutyrate. Hydrogen is also produced. Major cellular fatty acids consist of anteiso-C15:0 and iso-C15:0, and a number of additional acids are present in lower concentrations. A substantial portion of genes involved in carbohydrate utilization is devoted to pectin degradation and utilization, while those supporting growth on xylan in ruminal Prevotella could not have been revealed. On the basis of the presented results, a novel species, Prevotella pectinovora sp. nov. is proposed. The type strain is P4-76T (=DSM 29996T =ZIM B1020T).

The Effects of Medium-Chain Triglyceride Oil Supplementation on Endurance Performance and Substrate Utilization in Healthy Populations: A Systematic Review

Tomas J. Chapman-Lopez,Yunsuk Koh 대한비만학회 2022 Journal of obesity & metabolic syndrome Vol.31 No.3

Background: The use of medium-chain triglyceride (MCT) oil has increased due to its potential for therapeutic and ergogenic properties. Although recent evidence has suggested that MCT oil supplementation may lead to an improvement in endurance and substrate utilization, contradicting studies have reported the ergogenic benefits of MCT oil toward exercise performance. Methods: An extensive systematic review was conducted to assess the role of MCT oil as an ergogenic aid in exercise performance. Moreover, this study examined any alterations in substrate utilization and various physiological components while using MCT oil. The databases searched in this review were PubMed, Embase, CINAHL, and the Cochrane Library. Results: Most studies reported that MCT oil did not improve exercise performance and had no effect on respiratory exchange ratio, glucose concentration, fat and carbohydrate oxidation, and lactate concentration. Although ketones were increased when supplementing with MCTs, most studies demonstrated that the body could not utilize the MCT oil-induced ketones as its primary energy source during an acute bout of endurance exercise. Thirty grams of MCTs seems to be the safe maximal dosage to minimize adverse reactions during or after exercise. Conclusion: MCT oil showed very little to no ergogenic effects on exercise performance and substrate utilization in healthy populations. Future research is needed to examine the effects of long-term intake of MCT oil alongside various diets, perhaps a ketogenic diet, on exercise performance within different sports/exercises in a variety of populations.

Design Method for Variable FIR Digital Filters with Some Variable Parameters Using WLS

Toma Miyata,Naoyuki Aikawa 대한전자공학회 2009 ITC-CSCC :International Technical Conference on Ci Vol.2009 No.7

In the field of measurement signal processing, we should often change the characteristic of the stopband instantaneously. Such the filter that can change the frequency response instantaneously is called variable digital filters (VDFs). In this paper, we propose a design method of FIR VDFs with some variable parameters. The filter with the quasi-chebyshev characteristic is obtained by using an iterative weighted least square (WLS) method. Moreover, a memory required for the designing filter coefficients in the proposed method is less than that of the conventional method using SDP. The usefulness of the proposed design method is verified through some examples.

GAMMA-SPECTROMETRY IN ENVIRONMENTAL MONITORING OF NUCLEAR POWER

Tomas Cechak,Josef Cerndt,jaroslav Kluson,Ladislav Musilek,Lenka Thinova 대한방사선방어학회 2001 방사선방어학회지 Vol.26 No.3

Original Articles : Chemical Composition and Size of Floating and Sunken Eggs of Olive Flounder Paralichthys olivaceus

( Tomas Cabrera ),( Jean Hee Bae ),( Sung Bum Hur ) 한국수산학회 2005 Fisheries and Aquatic Sciences Vol.8 No.3

Gamma-Ray Bursts and Population III Stars

Toma, K.,Yoon, S. C.,Bromm, V. Springer Science + Business Media 2016 Space science reviews Vol.202 No.1

<P>Gamma-ray bursts (GRBs) are ideal probes of the epoch of the first stars and galaxies. We review the recent theoretical understanding of the formation and evolution of the first (so-called Population III) stars, in light of their viability of providing GRB progenitors. We proceed to discuss possible unique observational signatures of such bursts, based on the current formation scenario of long GRBs. These include signatures related to the prompt emission mechanism, as well as to the afterglow radiation, where the surrounding intergalactic medium might imprint a telltale absorption spectrum. We emphasize important remaining uncertainties in our emerging theoretical framework.</P>

The Influence of Megatren System on Ridership in Metro Manila

Tomas U. Ganiron Jr 보안공학연구지원센터(IJUNESST) 2015 International Journal of u- and e- Service, Scienc Vol.8 No.1

The inauguration of the Metro Rail Transit (MRT-2) or Megatren in line 2 with a total length of about 13.8 km and run from Santolan, Pasig City to Recto in Manila marked the comeback of the train as an important passenger mode of transport in the Philippines. Since then high speed train (HST) services have been introduced in ASEAN countries and are planned in many more, and the train has once more become the dominant mode of transport on many routes. This review summarizes the efficiency of the expanded rail network system which is quite modern through the application of technology and scientific principles by means of modern ways of transportation engineering for managing the facilities of MRT-2 system. The study further concludes that MRT-2 is less cost-efficient than private transportation, the benefits of MRT-2 such as aesthetics, providing transit for the poor, potential economic development spillovers, and reducing congestion and pollution—must all be considered in the cost-benefit analysis of MRT-2.