Endüstri MühendisliğiIndustrial Engineeringhttps://hdl.handle.net/20.500.12508/1222024-03-29T05:48:04Z2024-03-29T05:48:04ZA multi-objective approach to home health care routing problem with team formationBektur, GülçinNenbhard, Davidhttps://hdl.handle.net/20.500.12508/30492024-01-19T11:52:12Z2023-01-01T00:00:00ZA multi-objective approach to home health care routing problem with team formation
Bektur, Gülçin; Nenbhard, David
Home health care (HHC) services provide the elderly, disabled, and those with chronic diseases health services in their homes. The demand for HHC services has increased due to the growth of the elderly population, the increase in hospital occupancy rates during the pandemic, and developments in medical device technologies. In this study, team formation is taken into consideration in a multi-period and multi-objective HHC assignment, scheduling and routing problem. The team and the assigned patients to this team must be compatible with skill levels and operational requirements. The objective functions are minimization of total completion time and maximum working time overall caregivers. To evaluate our approach, an HHC service unit in a state hospital is adopted as the operational scenario, and we propose a multi-objective mathematical model to solve the problem. In this model, HHC teams are formed, the patients are assigned to the teams, and the route of each team is determined in an integrated manner. The variable neighborhood search algorithm is modified to solve the multi-objective optimization model and is improved with a local search algorithm. The proposed algorithm has been compared with the state-of-the-art multi-objective algorithms in the literature over test problems. Current results show that the model to be an effective means of estimating and predicting system behavior in this complex environment.
2023-01-01T00:00:00ZLignin activated carbon obtained by a environmentally friendly green production process using deep eutectic solventsAydemir, DenizErgün, Mehmet EminGülsoy, Sezgin KorayOzan, Zeynep EdaGündüz, Gökhanhttps://hdl.handle.net/20.500.12508/30422024-01-19T05:56:53Z2023-01-01T00:00:00ZLignin activated carbon obtained by a environmentally friendly green production process using deep eutectic solvents
Aydemir, Deniz; Ergün, Mehmet Emin; Gülsoy, Sezgin Koray; Ozan, Zeynep Eda; Gündüz, Gökhan
The aim of this study was to produce activated carbon (AC) from lignin obtained with deep eutectic solvents (DESs) of choline chloride–lactic acid. For this, lignin particles were produced using the DES. The DES lignin (DES-Lig) was modified with zinc dichloride, and the lignin activated carbon (lig-AC) was produced by carbonization at 600 and 900 °C. In this study, the AC obtained from the commercial lignin was also used to determine the changes in the lig-AC from the lignin obtained with the DES. The material properties were investigated using Brunauer–Emmett–Teller (BET) surface analysis, scanning electron microscopy (SEM) and thermogravimetric analysis (TGA), and the structural properties were investigated with X-ray diffractometry (XRD) of the lig-ACs. The commercial and DES-Lig exhibited different microscopic morphologies. The surface area of the samples generally ranged from 504 to 698 g/cm2, and they included both micro- and mesopores according to SEM characterization. The XRD analysis showed that the ACs obtained have an amorphous structure, and thermogravimetric analysis of the ACs exhibited similar thermal behavior to that in the literature. The best morphological structure was found in the ACs prepared from lignin with the DES at 900 °C according to the results of SEM, TGA, XRD and BET analysis. The proximate analysis showed that the best ACs contain 1.5% moisture, 6.5% volatile matter, 5.5% ash content and 86.5% fixed carbon. According to the elemental analysis, the amounts of essential elements, including C, H, N and O were investigated, and the best activated carbon was determined to be the DES-Lig at 900 °C according to BET and the proximate fixed carbon results.
2023-01-01T00:00:00ZTerrestrial biosphere water balance analysis: a mathematical model to predict the impacts of climate change on net water budget on global scaleSakallı, AbdullaÜnal, Bakihttps://hdl.handle.net/20.500.12508/30322024-01-18T07:21:44Z2023-01-01T00:00:00ZTerrestrial biosphere water balance analysis: a mathematical model to predict the impacts of climate change on net water budget on global scale
Sakallı, Abdulla; Ünal, Baki
The industrial revolution triggered increased greenhouse gas emissions, disrupting the water cycle, and raising global temperatures by 2°C. This shift has induced extreme weather, rising sea levels, altered precipitation, and high evaporation rate. Since agriculture, soil, and health of ecosystems are impacted adaptation and mitigation strategies are crucial. To investigate net water budget (NWB) changes in ecosystems, this study employed the Multi-Source Weighted-Ensemble Precipitation (MSWEP) dataset to assess NWB distribution. Global Land Evaporation Amsterdam Model (GLEAM) database analyzes global land evaporation, revealing a gradual NWB increase since 1980 with sporadic drops during severe droughts. Positive shifts are noted in tropics and mountains, while Egypt, Iraq, Russia, Canada, and Australia suffer declines. NWB variability is the highest in the tropics, temperate, and cold regions, necessitating adaptable water management. Coefficient of variation identifies sensitive zones like tropical and transition climate areas. Latitudinal NWB trends show rising inputs and outputs. Most affected is the "First Tropical Lowland Rain Forest" biome, experiencing significant shifts since 2000 due to input and climate changes. The tropics and transition zones of boreal and temperate climate zones have high sensitivity to NWB change, which is attributed to their unique climatic conditions and ecological characteristics. The sensitivity of most continents is also approximately 40%. The change in the latitudinal average of the NWB between 1980 and 2015 is significant, with inputs and outputs in the NWB increasing over time.
2023-01-01T00:00:00ZEnsemble multi-attribute decision-making for material selection problemsŞahin, Mehmethttps://hdl.handle.net/20.500.12508/30182024-01-17T06:09:44Z2023-01-01T00:00:00ZEnsemble multi-attribute decision-making for material selection problems
Şahin, Mehmet
Material selection is influential in product design, manufacturing, and marketing. Appropriate material selection maximizes the performance of a product while minimizing its cost, whereas inappropriate material selection creates devastating results such as low performance, low quality, and high cost. Therefore, it is crucial how to choose the most suitable material. Unlike other studies, this study presents an ensemble multi-attribute decision-making approach for material selection. The approach involves four weighting methods-criteria importance through intercriteria correlation, Entropy, the method based on the removal effects of criteria, and statistical variance, five ranking methods-additive ratio assessment, combined compromise solution, multi-attributive border approximation area comparison, range of value, and the technique for order performance by similarity to the ideal solution, Spearman's correlation coefficients, and the Copeland method. Three different problems are considered to show the applicability of the proposed method and to reveal a comprehensive analysis. The results of each problem show valuable implications. The results of the ranking methods are sensitive to attribute weights. No ranking method alone can assure dependable selection for a given problem. Overall, the results reveal the importance of using multiple weighting and ranking methods and the superiority of the proposed integrated approach.
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