Fuzzy Logic-Based on-off Controller for Home Heating System

Paulius Stankevi?ius,Vytautas Kaminskas,Tomas Krilavi?ius,Ka Lok Man 한국산업정보학회 2014 한국산업정보학회 학술대회논문집 Vol.2014 No.1

Design of a Two-tier Supply Chain Based on Integration, Pricing, Routing, and Inventory Control

Aruzhan Jussibaliyeva,Ius Rusnati,Aan Komariah,Aigul Kurmanalina,Nikolay N. Reutov,Gulnar Temirgaliyevna Kunurkulzhaeva,Alim Al Ayub Ahmed,Ravil Akhmadeev,Supat Chupradit 대한산업공학회 2021 Industrial Engineeering & Management Systems Vol.20 No.4

This paper integrates decisions about the three key components of the supply chain including pricing, routing and inventory control, and multi-product multi-cycle in a two-tier supply chain; includes a manufacturer and a collection of dedicated retailers. In addition to pricing, inventory management and distribution planning, production planning is also considered in the study. The goal is to maximize profits in the supply chain, where products are delivered to retailers by a fleet of limited-capacity identical vehicles under a multiple-delivery strategy. Also, limited production and storage capacity and unauthorized shortages are assumed. The proposed model will then be solved using CPLEX software package in GAMS environment and genetic algorithm in Matlab software to determine the optimal supply chain policy.

Nanowire Perovskite Solar Cell

Im, Jeong-Hyeok,Luo, Jingshan,Franckevič,ius, Marius,Pellet, Norman,Gao, Peng,Moehl, Thomas,Zakeeruddin, Shaik Mohammed,Nazeeruddin, Mohammad Khaja,Grä,tzel, Michael,Park, Nam-Gyu American Chemical Society 2015 NANO LETTERS Vol.15 No.3

<P>Organolead iodide perovskite, CH<SUB>3</SUB>NH<SUB>3</SUB>PbI<SUB>3</SUB>, was prepared in the form of nanowire by means of a small quantity of aprotic solvent in two-step spin-coating procedure. One-dimensional nanowire perovskite with the mean diameter of 100 nm showed faster carrier separation in the presence of hole transporting layer and higher lateral conductivity than the three-dimensional nanocuboid crystal. Reduction in dimensionality resulted in the hypsochromic shift of both absorption and fluorescence spectra, indicative of more localized exciton states in nanowires. The best performing device employing nanowire CH<SUB>3</SUB>NH<SUB>3</SUB>PbI<SUB>3</SUB> delivered photocurrent density of 19.12 mA/cm<SUP>2</SUP>, voltage of 1.052 V, and fill factor of 0.721, leading to a power conversion efficiency (PCE) of 14.71% at standard AM 1.5G solar illumination. A small <I>I</I>–<I>V</I> hysteresis was observed, where a PCE at forward scan was measured to be 85% of the PCE at reverse scan.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/nalefd/2015/nalefd.2015.15.issue-3/acs.nanolett.5b00046/production/images/medium/nl-2015-00046q_0009.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nl5b00046'>ACS Electronic Supporting Info</A></P>

Effects of growth temperature on exciton lifetime and structural properties of ZnO films on sapphire substrate

Cho, S.,Kim, S. I.,Kim, Y. H.,Mickevič,ius, J.,Tamulaitis, G.,Shur, M. S. WILEY-VCH Verlag 2006 Physica status solidi. PSS. A, Applications and ma Vol.203 No.15

<P>We report on optimization of growth conditions by studying the structural and optical properties of ZnO films grown on sapphire substrate by pulsed laser deposition at different growth temperatures. The crystallographic structure and surface morphology were studied by X-ray diffraction and atomic force microscopy, respectively. The flattest surface was observed in the sample grown at substrate temperature of 500 °C. The optical characterization was performed by steady state and time resolved photoluminescence spectroscopy. Photoluminescence of the samples was studied at low CW excitation and at high-power-density pulsed excitation in picosecond domain. Stimulated emission was observed at pulsed excitation. Carrier lifetimes were found to significantly depend on the growth temperature reaching the peak value also in the samples grown at approximately 500 °C. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)</P>

Numerical investigation of two-component single-phase natural convection and thermal stratification phenomena in a rod bundle with axial heat flux profile

Graževičius Audrius,Šeporaitis Marijus,Valinčius Mindaugas,Kaliatka Algirdas 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.8

The most numerical investigations of the thermal-hydraulic phenomena following the loss of the residual heat removal capability during the mid-loop operation of the pressurized water reactor were performed according to simplifications and are not sufficiently accurate. To perform more accurate and more reliable predictions of thermal-hydraulic accidents in a nuclear power plant using computational fluid dynamics codes, a more detailed methodology is needed. Modelling results identified that thermal stratification and natural convection are observed. Temperatures of lower monitoring points remain low, while temperatures of upper monitoring points increase over time. The water in the heated region, in the upper unheated region and the pipe region was well mixed due to natural convection, meanwhile, there is no natural convection in the lower unheated region. Water temperature in the pipe region increased after a certain time delay due to circulation of flow induced by natural convection in the heated and upper unheated regions. The modelling results correspond to the experimental data. The developed computational fluid dynamics methodology could be applied for modelling of two-component single/ two-phase natural convection and thermal stratification phenomena during the mid-loop operation of the pressurized water reactor or other nuclear and non-nuclear installations at similar conditions

Optimal Schemes of Tall Pinned Masts

Rimantas Belevičius,Donatas Jatulis,Dainius Rusakevičius 대한토목학회 2024 KSCE Journal of Civil Engineering Vol.28 No.2

A procedure for simultaneous topology, shape, and sizing optimization of tall pinned guyed masts is presented in the paper, seeking the minimal total mass of the mast structure including guys. The typical schemes of tall telecommunication masts of four different heights with different antenna areas distributed in the top 15% of the mast height that is triangular in plan and supported by two to four guys’ clusters are examined. The mast structure is optimized for self-weight and wind loading evaluated according to Eurocodes. Since the non-gradient stochastic optimization algorithm requiring thousands of problem solutions is used, the non-linear behaviour of the guyed mast is mimicked by a suggested approximate linear analysis procedure. The optimization constraints involve all strength, local, and global stability requirements. Analysis of the optimization results leads to the following most important findings: at equal conditions of the mast scheme, a higher number of guys’ clusters always reduces the mast mass; in case of four guys’ clusters levels the anchoring points of the top and the next-to-last level guys should be superposed. Also, the optimal ranges of pre-stresses in guys of different levels, their inclination angles, and the ratios of spans between guys’ levels are provided.

Comparative study of CFD and 3D thermal-hydraulic system codes in predicting natural convection and thermal stratification phenomena in an experimental facility

Graževičius Audrius,Bousbia-Salah Anis 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.4

Natural circulation phenomena have been nowadays largely revisited aiming to investigate the performances of passive safety systems in carrying-out heat removal under accidental conditions. For this purpose, assessment studies using CFD (Computational Fluid Dynamics) and also 3D thermal-hydraulic system codes are considered at different levels of the design and safety demonstration issues. However, these tools have not being extensively validated for specific natural circulation flow regimes involving flow mixing, temperature stratification, flow recirculation and instabilities. In the present study, an experimental test case based on a small-scale pool test rig experiment performed by Korea Atomic Energy Research Institute, is considered for code-to-code and code-toexperimental data comparison. The test simulation is carried out using the FLUENT and the 3D thermal-hydraulic system CATHARE-2 codes. The objective is to evaluate and compare their prediction capabilities with respect to the test conditions of the experiment. It was observed that, notwithstanding their numerical and modelling differences, similar agreement results are obtained. Nevertheless, additional investigations efforts are still needed for a better representation of the considered phenomena.

Growing partnership between Lithuania and South Korea

Ričardas Šlepavičius 한국외국어대학교 EU연구소 2024 EU연구 Vol.- No.69

Dynamic Research of Multi-Body Mechanical Systems of Angle Measurement

Artūras Kilikevičius,Albinas Kasparaitis 한국정밀공학회 2017 International Journal of Precision Engineering and Vol.18 No.8

Analysis of the influence of vibrations on the calibration uncertainty of an angle limb is crucial for achieving high calibration accuracy. In modern equipment, the calibration is implemented in dynamic mode when the position of the raster elements is detected in the motion of the comparator’s movable components. The research object of this work is a newly designed angle measurement comparator that operates in dynamic mode. The main aim of this research is to determine the dynamic effects influence to the accuracy of the angle comparator. During the modelling of calibration errors related to dynamic influences, it is necessary to evaluate elastic deformations related to the vibrations excited by internal and external sources. Dangerous resonance frequencies and the character of the elastic deformations of the precise angle comparator carriage, which increase the angle calibration error, were evaluated. The novelty of the research should show that the elastic deformation of main component, caused by dynamic effects, has a significant influence to an accuracy of the precision systems, which are working in dynamic mode. The evaluation of the dynamic effects is necessary during the design and exploitation of precision measurement systems.

Effect of low frequency oscillations during milking on udder temperature and welfare of dairy cows

Antanas Sederevičius,Vaidas Oberauskas,Rasa Želvytė,Judita Žymantienė,Kristina Musayeva,Juozas Žemaitis,Vytautas Jūrėnas,Algimantas Bubulis,Joris Vėžys 한국축산학회 2023 한국축산학회지 Vol.65 No.1

The study aimed to investigate the effect of low-frequency oscillations on the cow udder, milk parameters, and animal welfare during the automated milking process. The study’s objective was to investigate the impact of low-frequency oscillations on the udder and teats’ blood circulation by creating a mathematical model of mammary glands, using milkers and vibrators to analyze the theoretical dynamics of oscillations. The mechanical vibration device developed and tested in the study was mounted on a DeLaval automatic milking machine, which excited the udder with low-frequency oscillations, allowing the analysis of input parameters (temperature, oscillation amplitude) and using feedback data, changing the device parameters such as vibration frequency and duration. The experimental study was performed using an artificial cow’s udder model with and without milk and a DeLaval milking machine, exciting the model with low-frequency harmonic oscillations (frequency range 15–60 Hz, vibration amplitude 2–5 mm). The investigation in vitro applying low-frequency of the vibration system’s first-order frequencies in lateral (X) direction showed the low-frequency values of 23.5–26.5 Hz (effective frequency of the simulation analysis was 25.0 Hz). The tested values of the first-order frequency of the vibration system in the vertical (Y) direction were 37.5–41.5 Hz (effective frequency of the simulation analysis was 41.0 Hz), with higher amplitude and lower vibration damping. During in vivo experiments, while milking, the vibrator was inducing mechanical milking-similar vibrations in the udder. The vibrations were spreading to the entire udder and caused physiotherapeutic effects such as activated physiological processes and increased udder base temperature by 0.57℃ (p < 0.001), thus increasing blood flow in the udder. Used low-frequency vibrations did not significantly affect milk yield, milk composition, milk quality indicators, and animal welfare. The investigation results showed that applying low-frequency vibration on a cow udder during automatic milking is a non-invasive, efficient method to stimulate blood circulation in the udder and improve teat and udder health without changing milk quality and production. Further studies will be carried out in the following research phase on clinical and subclinical mastitis cows.