Science :

 Solid State

Researches : 

Ferromagnetic Rezonance (FMR)

Magnetic Granular Films

Magnetic Nano-particles

Nuclear Magnetic Rezonance (NMR)

Spin-spin relaxation times (T2)

Spin-lattice relaxation times (T1)

 Mikrowave Spectroscopy (MW) Liquids Dielektric constants e1,e2)

1-) Metin ŞİMŞEK, “SUBSTANCE DETECTİON AND CLASSİFİCATİON BY ANALYSİS OF EARTH FİELD NUCLEAR MAGNETİC RESONANCE (EF-NMR) SPECTROMETER MEASUREMENT DATA USİNG SİGNAL PROCESSİNG AND MACHİNE LEARNİNG TECHNİQUES”, Marmara Üniversitesi, Fen Bilimleri Enstitüsü, (Başlangıç: 30 Mart 2023-Bitiş: 11 Haziran 2024.)

ABSTRACT
For the safety and security of people in the modern world, it is extremely important to detect and distinguish dangerous, explosive and illegal chemical substances. A wide variety of techniques are available for the detection of hazardous liquids and explosive chemicals, such as backscatter X-ray, thermal neutron analysis (TNA), ion mobility spectrometry (IMS), and gas chromatography (GC), Nuclear magnetic resonance (NMR).
Nuclear Magnetic Resonance (NMR) is one of the most important and a non-invasive (without opening the Box/Bottle) method that enables the determination and analysis of liquids and solids at microscopic dimensions. For this reason, it is widely used in medicine, safety applications, agriculture and food industry, etc. It has also very productive results can be obtained in the quality control processes in the fields. Earth's Field Nuclear Magnetic Resonance (EF-NMR) technique is a sub-type of the NMR technique, has an important place in terms of its application area. Thanks to perfectly homogeneous structure of the earth's magnetic field, NMR spectrums can be obtained without using cryogenic system. Although it cannot be measured as precisely as the measurements made using a super strong magnetic field, it provides a cost-effective solution which largely compensates for these disadvantages. Since both hazardous and benign liquids have similar datasets, it is difficult to distinguish samples directly from measurement data. However, with the developing technology, machine learning techniques are used in many areas. Machine learning have many application areas such as classification, regression, anomaly detection, clustering, dimensional reduction with number of different algorithms applied.  One of these techniques, and the most widely used classification, is used to determine which class a new observation with an unknown label belongs to, using a data set of data with known labels.
In this thesis study; The NMR spectrum data of hazardous liquids and chemical substances obtained from the nuclear magnetic resonance (EF-NMR) spectroscopy technique in the earth's magnetic field along with Random Forest Classification (RFC), k Nearest Neighbor (kNN) and Logistic Regression (LR) machine learning models for quick classification and separation of chemicals from each other will be used.

1-)Eray Emre ŞENTÜRK “Estimation Studies with Machine Learning Algorithms and Relaxation Times of Edible Oil” Marmara Üniversitesi, Fen FAKÜLTESİ, (Başlangıç:  Şubat 2022 -Bitiş: Haziran 2022.)

ABSTRACT
Nanoscience breakthroughs in almost every field of science and nanotechnology make life easier in this age. Nanotechnology and nanoscience represent an expanding field of research, involving structures, devices and systems with new properties and functions due to the arrangement of their atoms on the 1 100 nm scale. The early 2000s have created an environment of awareness and discussion regarding nanotechnology, on the other hand, it is accepted as the beginning of the commercial applications of nanotechnology. Nanotechnological developments, especially in recent years, contribute to almost every field of science, including physics, materials science, chemistry, biology, computer science and engineering, medicine. This project tries to understand the nature of the applications in these fields by drawing attention to the advancement of nanotechnology, nanoscience, today’s application areas, nanotechnological materials and their properties (mechanical, electrical, optical, magnetic, thermal). In addition, it would be appropriate to review the timeline of nanotechnological discoveries and examine the current and future effects of nanotechnology.

2-) Aysu SANAN, “Classification of Milk and Investigation of Water-Milk Mixture by Time Domain NMR Technique”, Marmara Üniversitesi, Fen FAKÜLTESİ, (Başlangıç:  Şubat 2023 -Bitiş: Haziran 2023.)

ABSTRACT

Since milk is the only food that people can consume for a certain period of time when they are born and they can meet the vitamins and minerals they need throughout their lives from milk, it has always been at the forefront of nutrition. The demand of people for milk has increased the competition rate of the producers and the rate of resorting to fraud. Corruption is the cheapest and most common cheating method for the producers. Food adulteration is one of the most common food frauds. It is made by adding impurities to foods to hide poor quality or gain more profit. The adulteration of food goes beyond direct economic concerns as it will affect consumer confidence and, more importantly, the health of the consumer. Time-domain Nuclear Magnetic Resonance (TD-NMR) technique has started to be used in food analysis since it can analyze the content of the product, which cannot be distinguished by sensory characteristics, in a simple, fast and high efficiency way. In this study, spin-knit (T1) and spin-spin (T2) relaxation times were measured using the Bruker Minispec mq-20 model TD-NMR device. The results obtained demonstrate the success of the TD-NMR method and the analysis of the results.

3-) İrfan HATİP, "Classification of Milk and Investıgation of Water-Milk Mixture by Microwave (MW) Technique”, Marmara Üniversitesi, Fen FAKÜLTESİ, (Başlangıç:  Şubat 2023 -Bitiş: Haziran 2023.)

ABSTRACT

Milk has been determined as the most perfect food in terms of nutritional value. Milk consumption is high, especially in developing countries. Currently, it is an important part of nutrition for a large part of the world's population. As a result of the increased demands, competition in the milk market has increased and some producers have started to cheat. The most common of these cheats is the adulteration of milk. Adulteration is the process in which the quality or nature of a particular food is reduced by adding or removing adulterants.Microwave technique has started to be used in food analysis because it can analyze the content of products that cannot be distinguished from each other by sensory characteristics in a simple, fast and highly efficient way. In this study, ?1 and ?2 values of milk with different fat ratios purchased from local markets were measured using Agilent E8364B PNA series vector network analyzer and VNA Agilent 85070E Dielectric kit. The results obtained demonstrate the success of the Microwave method and the analysis of the results.

4-) Elif TOY, “Estimation Studies with Machine Learning Algorithms and Relaxation Times of some Liquid Chemicals”, Marmara Üniversitesi, Fen FAKÜLTESİ, (Başlangıç:  Şubat 2024 -Bitiş: Haziran 2024.)

ABSTRACT

Safe and unsafe liquids or illegal liquid materials obtained by using liquid chemicals are one of the most important problems of today. Time-dimensional Nuclear Magnetic Resonance (TD-NMR) technique has been started to be used in liquid analysis because it can analyze the contents of the product, which cannot be distinguished by sensory characteristics, in a simple, fast and highly efficient way. In this study, the spin-spin (T2) settling times of the (%99) pure Acetone, Ethanol, Methanol, Isopropanol liquids obtained from Sigma-Aldrich company, Riviera Olive Oil, Di-Water, edible Komili bought from the local store were measured. In addition, classification studies were carried out with the prediction results obtained from machine learning models K-Nearest Neighbor (KNN), Random Forest Classifier (RFC) and Logistic Regression (LR) using the data obtained from T2-spectra. It has been observed that it has a %100 accuracy rate in machine learning models (RFC, KNN and LR) for acetone and edible Komili Riviera Olive Oil in different categories. For Di-Water and methanol liquids with T2 values close to each other, an accuracy rate of %99, %78 and %86 was obtained in the RFC, KNN and LR models, respectively. In for 5 liquids samples (Acetone, Ethanol, Methanol, Isopropanol, Di-Su ), %93, %52 and %36 accuracy rates were obtained in the RFC, KNN and LR models, respectively. The results obtained reveal the success of using TD- NMR method and machine learning together.

5-) Beyza ÖRTEN, “Investigation of Relaxation Times of some Liquid Chemicals by Time Domain NMR”, Marmara Üniversitesi, Fen FAKÜLTESİ, (Başlangıç:  Şubat 2024 -Bitiş: Haziran 2024.)

ABSTRACT

Time-dimensional nuclear magnetic resonance (TD-NMR) is an important technique because it provides information about the molecular dynamics of various liquid chemicals and their mixtures thanks to spin lattice (T1) and spin-spin (T2) relaxation time measurements. In this study, two different proton NMR devices were used to measure the relaxation times of some liquid chemicals: Bruker Minispec mq-20 time-dimensional NMR and high-resolution 42MHz Magritek Spinsolve NMR. It was clearly seen that the spin lattice (T1) and spin-spin (T2) values obtained by both devices had the same tendency. It has been found that the magnetic field gradient (inhomogeneity) value of the high-resolution Magritek Spinsolve NMR device is better than the Bruker Minispec device and as a result, it has longer T1 and T2 relaxation times.

.

6-) Beyzanur EROl, “Investigation of Temperature Dependence of Relaxtion Times in Some Liquid Chemicals and Foods”, Marmara Üniversitesi, Fen FAKÜLTESİ, (Başlangıç:  Şubat 2024 -Bitiş: Haziran 2024.)

ABSTRACT
Investigation of Temperature Dependence of Relaxtion Times in Some Liquid Chemicals and Foods

Spin-lattice (longitudinal, T1), spin-spin (transverse, T2) relaxation times of some liquid chemicals and foods were obtained using a time-dimensional nuclear magnetic resonance (TD-NMR) device in the temperature range of 15 to 70 °C. The measurement findings showed that the T1 value was longer than the T2 value and that the T1 and T2 values rose with temperature for each food and chemical group. This study examined how temperature affects viscosity, T1 and T2 relaxation times, and as a result, it provides a detailed explanation of how rising temperatures cause viscosity values of liquid chemicals and foods to decrease while increasing T1 and T2 relaxation times.