Siirt Üniversitesi Kurumsal Akademik Arşivi
DSpace@Siirt, Siirt Üniversitesi tarafından doğrudan ve dolaylı olarak yayınlanan; kitap, makale, tez, bildiri, rapor, araştırma verisi gibi tüm akademik kaynakları uluslararası standartlarda dijital ortamda depolar, Üniversitenin akademik performansını izlemeye aracılık eder, kaynakları uzun süreli saklar ve telif haklarına uygun olarak Açık Erişime sunar.
Güncel Gönderiler
Temporal analysis of agricultural water footprint dynamics in Türkiye: Climate change impacts and adaptation
(Elsevier BV, 2025-08) Muhammed Sungur Demir; Abdullah Muratoglu; Veysi Kartal; Hüsamettin Nas
Climate change intensifies pressures on agricultural water resources, particularly in arid and semi-arid regions. This study evaluates the interplay between climate variability and agricultural water footprint (WF) dynamics in Türkiye from 1990 to 2019, integrating trend analyses of WF components, virtual water content (VWC), and climate parameters. We assessed temporal trends and correlations using the Mann-Kendall test, Sen's slope estimator, and Innovative Trend Analysis, focusing on 11 major crops. While some crops, like alfalfa, showed decreased yields and increased VWC, key crops (maize, wheat, cotton) exhibited substantial yield improvements, with some showing VWC reductions of up to 46 %. A key finding is that socio-economic and technological advancements have offset the negative effects of rising temperatures and declining relative humidity on evapotranspiration, leading to an overall reduction in the total agricultural water footprint. However, blue WF concurrently increased, signaling a growing reliance on irrigation. Climate correlations revealed distinct seasonal influences: June–July precipitation was inversely correlated with blue WF (r = −0.531), while spring (March–May) rainfall positively influenced green WF (r = 0.412). The observed decoupling of agricultural productivity growth from total WF reduction highlights the importance of technological advancements and optimized water use. However, the rising blue-to-green water ratio underscores sustainability risks in groundwater-dependent systems. These findings advocate for crop-specific adaptive strategies and integrated policies to reconcile agricultural productivity with water resource resilience under climate change. This study provides a framework for guiding sustainable water management in water-stressed regions facing climatic uncertainty.
Optimization study of a hybrid renewable energy system for co-production of electricity and heat at a hydrogen refuelling station
(Elsevier BV, 2025-07) Berna Burcu Kalyoncu; Yavuz Kırım; Hasan Sadikoglu
The purpose of this study is to identify the best hybrid renewable energy system (HRES) configuration for a hydrogen refuelling station located in Schleswig, Holstein. Techno-economic analysis and configuration simulations are performed using the Hybrid Optimization of Multiple Energy Resources (HOMER) Pro program. Initially, HRES powered by photovoltaics (PV) and two different wind turbines (WT) are proposed, achieving 100 % renewable fraction. Alternative configurations include a thermal load controller (TLC), a boiler and a micro gas turbine (MGT). The renewable fractions of these configurations are reduced to over 40 %. The best system configuration comprises PV panels, XANT L-36 WT, Vestas V47 WT, hydrogen storage tank, electrolyser, battery, TLC, boiler, and MGT, with net present cost (NPC) of $6.28 million. Furthermore, four regression models are utilized for the econometric evaluation of global green hydrogen production in the R programming language (R). The ridge regression (RR) model demonstrates the best performance, providing a good fit for our data.
Enzyme Inhibition Properties of Calendula officinalis, Matricaria chamomilla, and Anthemis pseudocotula: Kinetics and Molecular Docking Studies
(ACG Publications, 2025-06-15) İlhami Gülçin; Kübra Aslan; Hatice Kızıltaş; Leyla Guven; Hasan Karageçili; Doğan Arslan
This study determined the enzyme inhibition potential of three species (Calendula officinalis, Matricaria chamomilla, and Anthemis pseudocotula) from the Asteraceae family through in silico, followed by in vitro studies. Quinic acid, fumaric acid, gallic acid, chlorogenic acid, vanillic acid, quercetin, apigenin, and isorhamnetin were determined by LC-MS/MS in all of the species. Metabolic enzymes are essential catalysts regulating biochemical reactions within living organisms, facilitating energy production, detoxification, and biosynthesis. These enzymes play a crucial role in maintaining cellular homeostasis and are tightly regulated to ensure optimal metabolic function. High docking scores were also obtained for butyrylcholinesterase (BChE), α-glycosidase, α-amylase, and human carbonic anhydrase I and II enzymes (hCA I and hCA II). Among the extracts, Anthemis pseudocotula was concluded to be the best inhibitor for the enzymes, which was further determined by in vitro enzyme inhibition tests. Besides, it was concluded that all extracts showed anti-cholinergic, anti-diabetic, and anti-glaucoma properties. This is the first study determining the enzyme inhibition property of Anthemis pseudocotula and the three species' hCA I and hCA II inhibition activities.
Interactions of soliton solutions for the generalized viscous capillarity compressible fluid model
(Informa UK Limited, 2025-06-23) Baboucarr Ceesay; Nauman Ahmed; Muhammad Zafarullah Baber; Ali Akgul; Muhammad Jawaz
In this work, interactions in a generalized viscous capillarity compressible fluid model are studied analytically employing the approach of Hirota bilinear transformation. We examine the conservation laws of the p-system with a generalized cubic van der Waals flow, nonlinear viscosity, and capillarity factors. This approach is used in the study to show numerous novel wave shapes and solitary solutions in compressible isothermal viscosity-capillarity van der Waals fluids. With the help of Mathematica, we extract various wave phenomena such as bright and dark breathers, kink, anti-kink, periodic lumps, periodic cross kink, M-shaped, mixed and multiple wave structures. The 3D dynamical behaviours and their related contour profiles for the obtained solutions are presented. The Hirota bilinear transformation approach's effectiveness and clarity, as shown in this paper, underscore its potential as a useful tool for deciphering complex physical processes.
Eco-Friendly Synthesis of Acetoguanamine Crown Ethers, Determination of Antioxidant and DNA Damage-Protection Properties
(Bentham Science Publishers Ltd., 2025-05-23) Baki Çiçek; Selma Yardan; Ümit Çalışır
Crown ethers are commonly used for metal complexation due to their affinity for cations. These compounds have a hydrophobic outer cavity and a hydrophilic inner cavity. They show an interest in various elemental ions depending on the number, proportions, and diversity of functional groups and donor atoms. The research focuses on synthesizing and characterizing compounds containing different heteroatom-containing groups on the side group, and the investigation of antioxidant and DNA damage-protection properties. Acetoguanamine (2,4-diamino-6-methyl-1,3,5-triazine), a heterocyclic compound that belongs to the triazine class and acts as an intermediate in numerous pharmaceuticals, was synthesized in this study as a crown ether derivative. This was achieved using the SN2 mechanism of 2,4-diamino-6-methyl-1,3,5-triazine and poly(ethylene) glycol dihalides. The reaction utilized a basic catalyst (Cs2CO3) and a microwave-assisted synthesis method. The targeted acetoguanamine crown ether derivatives were synthesized using green chemistry's eco-friendly (microwave-assisted synthesis) method in mild conditions, with quite high yields. After purification, the synthesized macrocyclic 2,4-diamino-6-methyl-1,3,5-triazine crown ether derivatives were characterized structurally using Fourier-Transform Infrared Spectroscopy (FTIR), Nuclear Magnetic Resonance (NMR), and tandem mass spectrometry - Liquid Chromatography (LC-MS/MS) methods. The synthesized compounds were investigated for their antioxidant and DNA damage-protective properties. Experimental tests showed that among the compounds, only S1 exhibited a radical scavenging effect (mean 5.62%), and none of the compounds affected the applied DNA plasmid, or demonstrated a DNA protection effect.
