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Comparison of the mechanical properties and drilling performance of the AISI 316 parts produced with casting, LPBF and WAAM
(Springer Science and Business Media Deutschland GmbH, 2024) Kocaman, Engin; Köklü, Uğur; Morkavuk, Sezer; Coşkun, Mert; Koçar, Oğuz; Dilibal, Savaş; Gürol, Uğur
AISI 316 stainless steel parts are widely utilized in many industrial fields with a vast scope of applications. These steel parts, which are used in many fields, can be produced using different production methods, but the mechanical properties of the parts produced with different processes may be different, and the machinability characteristics will also be different. In this study, the drilling machinability characteristics of AISI 316 stainless steel parts manufactured via cast, LPBF and WAAM methods were experimentally investigated and compared considering thrust force generation, burr analysis and chip morphology. In order to clarify the differences in machinability behavior among the tested samples, the corresponding microstructure, microhardness and mechanical strength (yield strength, UTS and elongation) were also examined in detail. The experimental results showed the manufacturing method, and particularly cooling rate, significantly affecting the microstructure, mechanical response and further machinability characteristics; besides, due to higher cutting forces generation, the machinability of the parts produced by additive manufacturing methods (LPBF and WAAM) is more difficult compared to the parts produced by conventional manufacturing methods (cast and cast-HT).
Mechanical and ballistic performance of high-hardness armor steels welded with ASS-LHF sandwich joint design
(Elsevier Ltd, 2025) Gürol, Uğur; Çelik, Ceren; Çoban, Ozan; Göçmen, Müesser; Koçak, Mustafa
Armor steels are widely recognized for their exceptional mechanical and ballistic performance, particularly in the fabrication of armored vehicles. Austenitic stainless steel (ASS) wires are commonly used in their welding processes to mitigate hydrogen-induced cracking. However, joints formed using ASS often suffer from reduced ballistic performance due to the strength mismatch (undermatching) compared to the base material. This study explores the application of butt joints, integrating low hydrogen ferritic (LHF) deposits between softer ASS weld layers, which can be expressed as sandwich layer design, in gas metal arc welded (GMAW) armor steel plates. The mechanical properties were evaluated through hardness, tensile, and Charpy V-notch impact tests. Ballistics test performances were measured using depth of penetration (DoP) and width of penetration (WoP) values. The microstructural analysis utilized stereo, optical, and scanning electron microscopes. The results demonstrated that the sandwich joint configuration met the Charpy-V impact toughness requirements of the base metal, achieving 31.4 J and 65 J at −40 °C for the WM and HAZ regions, respectively, compared to 20 J for the base material. Moreover, this innovative joint design effectively combined the high toughness and ductility of austenitic wire, reaching a low DoP value of 7.2 mm, with the superior strength of ferritic filler metal, which contributes to a low WoP value of 12.5 mm and a joint efficiency of 48 %. By combining these properties, the joint design significantly enhances ballistic performance in welded regions, traditionally considered vulnerable to ballistic threats, without compromising overall mechanical integrity.
Effect of post-deposition heat treatments on high-temperature wear and corrosion behavior of Inconel 625
(Elsevier Ltd, 2025) Kocaman, Engin; Gürol, Uğur; Günen, Ali; Çam, Gürel
This study uses the arc-directed energy deposition method to fabricate and heat treatment of a Ni-based Inconel 625 wall structure. Heat treatment involved solution treatment at 980°C with and without aging at 720°C, comparing results to the as-built condition. The effects of these heat treatments were analyzed through microstructural investigations, nanoindentation tests, and high-temperature wear and corrosion tests in 0.5 M NaCl and 0.5 M HCl solutions. In the as-built state, the Inconel 625 alloy exhibited a columnar dendritic structure predominantly composed of a gamma matrix along with Laves phase and MC carbides. Solution treatment dissolved the Nb-rich Laves phases and encouraged the formation of needle-like particles in regions with high Nb segregation, while also reducing voids and minimizing corrosion susceptibility along grain boundaries. This resulted in the formation of a uniform oxide layer on the surface, significantly enhancing wear and corrosion resistance. Both heat-treated samples showed improvements in mechanical ratios such as H/E, H³/E², and H²/2E in the WAAM-produced Inconel 625 alloy, resulting in a 67 % enhancement in wear resistance compared to the as-built sample. Corrosion tests also revealed that solution treated samples showed the highest corrosion resistance, followed by aged treatment and as-built samples, respectively. In conclusion, this study provides a thorough understanding of the substantial impact of heat treatments on the microstructure, mechanical properties, and corrosion resistance of Inconel 625, offering valuable insights for advancements in the field.
Design today save future
(Istanbul Gedik University, 2019) Yahya, Noorhana; Pereira, Carlos Mourão; Canci Matur, Utku; Özbudak, Özgün; Önal, Feride; Tolon, Mart; Karabuga, Arif
Along with the development of technology, industrialization and rapid population growth have increased the energy demand. The awareness of the energy crisis has led researchers to search for new solutions and use new technologies in this area. Renewable energy has an extremely important place in energy requirement of the countries with domestic resources, reducing the external dependency, diversifying the resources and ensuring sustainable energy usage and minimizing the damages to the environment as a result of energy consumption. Today, around 20 percent of the world’s consumed energy is supply from renewable sources. Despite the high level of dependence on fossil fuels in the current situation, the use of renewable energy has been increasing steadily over the years. The conventional energy sources that already supply most of the energy demand. However, it is estimated that fossil fuels, especially petroleum, will be consumed in the next 200-300 years. In order to be able to produce solutions for this situation, it is necessary to carry out many research/development and production/development projects related to both conventional energy sources and alternative energy sources.
Innovative surface improvement of GFRC using hydrothermally produced Ch-TiO2-CuO nanohybrid composite additives
(Elsevier Ltd, 2024) Ramazanoğlu, Doğu; Subaşı, Serkan; Maraşlı, Muhammed
This study examines the impact of the Ch-TiO2-CuO nanohybrid composite on the surface properties and antimicrobial effects of Glass fiber-reinforced concrete (GFRC) panels. GFRC panels are known for their durability and aesthetic compatibility, making them suitable for exterior facades and historic restoration work. However, their porosity and hydrophilic nature make them susceptible to microbial colonization, affecting their durability and visual appeal. To address this, antimicrobial nanohybrid crystals (Ch-TiO2-CuO) were developed using a hydrothermal method and incorporated into GFRC panels. This integration offers significant advantages, including reduced maintenance, long-term structural integrity, and preserved aesthetic properties. Additionally, this approach aligns with sustainability goals by enhancing the environmental friendliness of GFRC over its lifetime. The study concludes that incorporating antimicrobial agents into GFRC production supports smart city initiatives by providing long-term protection against microbial degradation while maintaining aesthetic standards, thus contributing to cleaner, safer urban environments.
Study of the problem of one-dimensional flow of homogenous fluids in fractal porous media
(Springer Science and Business Media Deutschland GmbH, 2024) Aliyev, Nihan; Rasulov, Mahir; Sinsoysal, Bahaddin
In this paper, for the first time the exact solution in the form of Mittag-Leffler series for the initial-boundary problem of the fractional differential equation is obtained expressing the process of one-dimensional motion in porous medium with complex permeability homogeneous fluid to gallery. The obtained result permits the theoretical calculations in the process of exploitation of oil fields with a fractal nature.
Could DTI unlock the mystery of subjective tinnitus: it's time for parameters that go a little out of the routine
(Springer, 2024) Yılmaz, Eren; Yıldırım, Düzgün; Tekcan Şanlı, Deniz Esin; Elpen, Pınar; Gösterişli Tüzüner, Filiz; Gökmen İnan, Neslihan; Şirin, Ahmet; Yağımlı, Mustafa; Tozan, Hakan; Şanlı, Ahmet Necati; Kandemirli, Sedat Giray
In this study, it was aimed to assess the microstructural changes in the main central auditory pathway in cases with subjective tinnitus. In total, 101 subjects (52 cases with bilateral subjective non-pulsatile tinnitus and 49 healthy cases as the control group) were included in the study. Participants underwent pure tone audiogram and Diffusion Tensor Imaging-Magnetic Resonance Imaging (DTI-MRI) examination with a 3 Tesla MRI device. The number of tracts, tract length, volume, and quantitative anisotropy (QA) and normalized quantitative anisotropy' (nQA) values were calculated by plotting cochleocortical pathways from the cochlear nerve to ipsilateral and contralateral Heschl's gyrus (HG). In pure tone audiometry, the control group had lower hearing thresholds than cases with tinnitus. Fibres and nQA values from the right cochlear nerve to the right HG were significantly lower in the tinnitus group than in the control group. Cochlear nuclei voxel counts were significantly decreased in the tinnitus group. Both cochlear nucleus volumes were higher in the tinnitus group than in the control group. nQA values in both cochlear nuclei were decreased in the tinnitus group. This study showed that the most commonly affected part in subjective non-pulsatile tinnitus cases is the cochlear nucleus. Therefore, the cochlear nucleus should be evaluated more carefully in cases presenting with subjective tinnitus.
Additively manufactured continuous processing reactor system for producing liquid-based pharmaceutical substances
(Multidisciplinary Digital Publishing Institute (MDPI), 2024) Khabiyev, Alibek; Dilibal, Savaş; Mussulmanbekova, Assel; Kanapiya, Magzhan; Kerimkulov, Daniyar
In this study, an AM-based continuous processing reactor system was designed, manufactured, and assembled on a laboratory scale for the generation of pharmaceutical substances with an improved process control. The developed AM-based (additively manufactured) continuous pharmaceutical reactor system for the synthesis of metronidazole derivatives aimed to optimize both the physical and the chemical processes with time savings. Using AM, we were able to build reactor subcomponents with complex designs and precise dimensions, which facilitated the precise control of the reaction parameters and reduced the amount of chemicals required compared to macroscale reactors. The assembly of the whole reactor system consisted of main reactor bodies, mixers, valves, heat exchangers, electrical motors, and a microcontroller system. The assembled reactor system revealed a continuous flow of reagents and ensured uniform mixing and reaction conditions, thereby increasing the process efficiency and product quality. Five metronidazole derivatives were synthesized via two continuous processes, involving metronidazole reduction and its subsequent reactions with terephthalic aldehyde and anthracen-9(10H)-one to form Schiff bases. The optimal conditions were determined as follows: compound A (72% yield, 120 min, 55 °C), compounds B and C (63% and 68% yield, respectively, 8 h, 65 °C), and compounds D and E (74% and 85% yield, respectively, 8 h, 45 °C).
Developing a novel hybrid model based on deep neural networks and discrete wavelet transform algorithm for prediction of daily air temperature
(Springer Science and Business Media B.V., 2024) Ghasemlounia, Redvan; Gharehbaghi, Amin; Ahmadi, Farshad; Albaji, Mohammad
The precise predicting of air temperature has a significant influence in many sectors such as agriculture, industry, modeling environmental processes. In this work, to predict the mean daily time series air temperature in Mu & gbreve;la city (AT(m)), Turkey, initially, five different layer structures of Long Short-Term Memory (LSTM) and Gated Recurrent Unit (GRU) deep learning-based neural network models through the seq2seq regression forecast module are developed. Then, based on performance evaluation metrics, an optimal DL-based layer network structure designed is chosen to hybridize with the wavelet transform (WT) algorithm (i.e., WT-DNN model) to enhance the estimation capability. In this direction, among potential meteorological variables considered, the average daily sunshine duration (SSD) (hours), total global solar radiation (TGSR) (kw. hour/m(2)), and total global insolation intensity (TGSI) (watt/m(2)) from Jan 2014 to Dec 2019 are picked as the most effective input variables through correlation analysis to predict AT(m). To thwart overfitting and underfitting problems, different algorithm tuning along with trial-and-error procedures through diverse types of hyper-parameters are performed. Consistent with the performance evaluation standards, comparison plots, and Total Learnable Parameters (TLP) value, the state-of-the-art and unique proposed hybrid WT-(LSTM x GRU) model (i.e., hybrid WT with the coupled version of LSTM and GRU models via Multiplication layer (x)) is confirmed as the best model developed. This hybrid model under the ideal hyper-parameters resulted in an R-2 = 0.94, an RMSE = 0.56 (degrees C), an MBE = -0.5 (degrees C), AICc = -382.01, and a running time of 376 (s) in 2000 iterations. Nonetheless, the standard single LSTM layer network model as benchmark model resulted in an R-2 = 0.63, an RMSE = 4.69 (degrees C), an MBE = -0.89 (degrees C), AICc = 1021.8, and a running time of 186 (s) in 2000 iterations.
Experimental investigation on waam-based functional hardfacing bimetallic part
(Technical Faculty in Bor, 2024) Akpınar, D. E.; Dilibal, Savaş; Gürol, Uğur
In the traditional production of functional bimetallic parts with hard surfaces, the materials for the hard surfaces are usually applied to a base metal, a process that is often complex, costly, and time-consuming. In this paper, the Wire Arc Additive Manufacturing (WAAM) process is proposed as an alternative approach for the production of functional bimetallic parts with hardfacing wire to increase wear resistance. In this study, the hard-facing bimetallic part was fabricated by depositing Hardcor 600 G hardfacing wire onto the deposited 316L Si austenitic stainless steel. After the initial visual inspection and digital X-ray tests, the hardness distribution and macro- and microstructural examinations were carried out. In the subsequent analyses, tensile and Charpy V-notch tests were carried out on the samples taken from the manufactured bimetallic part. The mechanical properties of the functional hard-facing bimetallic parts showed different properties of the bimetallic part, with the Hardcor 600 G side exhibiting higher strength compared to the SS 316L Si side. In addition, the Charpy-V notch test showed a notable difference in impact resistance, with the SS 316L Si side having the highest strength, the Hardcor 600 G side having the lowest strength, and the interface being in between. The results show that the WAAM process is a viable alternative to produce functional bimetallic components with hard surfaces, especially for applications requiring increased wear resistance.
High-performance PVdF-HFP/PEG-IL composites: the combined effects of PEG and ionic liquid on proton conductivity and dielectric characteristics
(Elsevier Ltd, 2025) Yılmazoğlu, Mesut; Okkay, Hikmet; Abacı, Ufuk; Çoban, Ozan
This study explores the influence of varying polyethylene glycol (PEG) concentrations on the properties of PVdF-HFP/PEG-IL polymer composites through comprehensive characterization techniques, including FTIR, SEM, TGA, DMA, XRD and the detailed assessments of proton conductivity, dielectric properties, and relaxation dynamics. In terms of conductivity, the addition of PEG markedly improves proton conductivity. The PVdF-HFP/PEG40-IL composite exhibits the highest conductivity, reaching 1.96 × 10⁻2 S/m at 1 MHz and 300 K, and increasing to 4.27 × 10⁻2 S/m at 420 K. Dielectric properties show that the dielectric constant (ε′) increases with PEG content at low frequencies but decreases at higher frequencies due to reduced ionic polarization. Notably, PVdF-HFP/PEG40-IL achieves a dielectric constant of 3.39 × 106 at 20 Hz, which decreases to 30.34 at 1 MHz. Dielectric loss (ε'') also rises with temperature, with PVdF-HFP/PEG40-IL demonstrating the highest dielectric loss, indicative of superior proton conduction and polarization capabilities. Relaxation dynamics, as evidenced by tanδ, reveal that relaxation time significantly decreases with both increased PEG content and temperature, dropping from 1.06 × 10⁻4 s to 2 × 10⁻6 s as PEG concentration increases from 10 % to 40 %. This reduction in relaxation time correlates with enhanced proton conductivity and faster dipole relaxation, indicating PEG effect as a plasticizer that reduces polymer viscosity and improves ion transport. In conclusion, incorporating PEG into PVdF-HFP-IL composites leads to substantial improvements in proton conductivity, dielectric properties, and relaxation dynamics. The results highlight the crucial role of PEG in optimizing the performance of polymer electrolyte composites, making them effective candidates for advanced energy storage and conversion applications.
İnsan - endüstriyel mobil robot etkileşiminde güvenlik önlemlerinin boyutlandırılması için nesne tespit modeli geliştirme
(Gazi Universitesi, 2024) Aslan, Tarık; Yağımlı, Mustafa
İnsan-robot etkileşiminde, güvenlik önlemleri için geleneksel olarak tek düzey güvenlik önlemleri uygulanır ve çalışanlara ait kriterler dikkate alınmaz. Bununla birlikte nesne tespit teknolojisi kullanılarak yeni bir yöntem geliştirilebilir; koruyucu donanım kullanımı ve yetki seviyeleri gibi çalışanlara özgü kriterleri tespit edilerek insan-robot etkileşimi risk seviyesi belirlenebilir ve risk büyüklüğüne bağlı olarak farklı büyüklükte güvenlik önlemleri uygulanabilir. Bu araştırmada, YOLOv5n, YOLOv8n ve SSD MobileNet V3 nesne tespit modelleri bu amaçla geliştirilmiş ve analiz edilmiştir. Bulgular, YOLO ailesine ait mimarilerin daha hızlı çalıştığını ve daha yüksek doğruluk seviyelerine ulaştığını ortaya koymuştur. YOLOv5n algoritması GPU kullanımı ile 650 FPS hıza ve test verileriyle yapılan değerlendirme sonucunda %95,7'lik bir F1 doğruluk değerine ulaşılmıştır. Sonuçlar, nesne tespit teknolojisinin yakınlık senyörleriyle eş zamanlı olarak uygulanabilecek bir doğruluk ve hıza ulaştığını ve endüstriyel mobil robotların güvenlik önlemleri almadan önce çalışanların özelliklerini tespit edebileceğini ve riskleri derecelendirebileceğini göstermektedir. Bu durum daha güvenli çalışma ortamı oluşmasına, gereksiz önlemlerin elimine ve operasyonel verimliliğin optimize edilmesine olanak verir. Ayrıca bu yöntem, güvenli çalışma ortamların sağlanmasına yönelik olarak birçok sektörde ve alanda da uygulanabilir.
Biomass-fueled organic rankine cycles: state of the art and future trends
(Multidisciplinary Digital Publishing Institute (MDPI), 2024) Heidarnejad, Parisa; Genceli, Hadi; Hashemian, Nasim; Asker, Mustafa; Al-Rawi, Mohammad
Biomass-fueled organic Rankine cycles (ORCs) are widely utilized technologies for power production because of their simplicity, low cost, and relatively high efficiencies. Furthermore, raw material availability and topographical independency make these systems preferable to other renewable-fueled power generation systems. A deep and comprehensive understanding of biomass-fueled organic Rankine cycles will provide researchers with a solid foundation to prioritize their investigations and assist future developments in this field. In this regard, feedstocks and their properties, biomass conversion mechanisms, and biomass-fueled power generation systems are discussed in this study. Power generation technologies based on coal and waste as feedstock have been widely investigated in the literature due to higher energy content and technological maturity. Additionally, depending on the type of biomass available, the scale of the power plant, and economic and environmental considerations, the most common technologies utilized for biomass conversion are combustion, gasification, and anaerobic digestion. Finally, the authors investigate various aspects of biomass-fueled organic Rankine cycles, including working fluids, analysis methods, and environmental issues. Since maximizing product yield is key in biomass-based power generation systems, technical assessment of these systems has been a primary focus of many studies. Further research is required on integrated environmental and socio-economic approaches, along with Machine Learning algorithms. Future advancements focusing on integration of feedstock with other renewable energy sources, efficient working fluids like nanofluids, and high-tech heat exchangers will drive the development of biomass-fueled ORC systems.
Determination of the properties of medium-density fiberboards produced using urea-formaldehyde resins modified with boron compounds
(North Carolina State University, 2024) Arslan, Recai; Karaçay, Ebru; Maraşlıoğlu, Derya; Tanrıverdi, Bilge Aslan; Fırat, Ebru; Tozluoğlu, Ayhan; Uğraş, Halil İbrahim; Candan, Zeki
Effects of adding different boron compounds to the urea-formaldehyde resin were evaluated relative to the physical, mechanical, and other properties of medium-density fiberboard (MDF). While the chemical addition of boric acid to the urea-formaldehyde resin increased the modulus of rupture and modulus of elasticity values of MDF boards, the physical and chemical additions of other boron compounds decreased those values. While there were no significant decreases in internal bond values, the chemical addition of boric acid and borax decahydrate to urea-formaldehyde resin increased the internal bond values of MDF boards. It was observed that in both types of addition, borax pentahydrate reduced the formaldehyde emission values of MDF boards the most and also reduced the burnt area by up to 30%. When the type of addition of boron compounds to urea-formaldehyde was compared, the addition of boron compounds at the resin formation stage showed better results in the properties of MDF boards than physical addition.
Structural and shielding effectiveness properties of (NiFe2O4/chopped strands) composites for 6.5-18 GHz applications (vol 35, 1407, 2024)
(Springer, 2024) Şahin, Ethem İlhan; İbrahim, Jamal-Eldin F. M.; Emek, Mehriban; Sinsoysal, Bahaddin; Amanzholova, Alina
In the Acknowledgements section of this article, the project number 22101001 relating to "Adana Alparslan Türkeş Science and Technology University—BAP Unit" was missed to incorporate. The complete Acknowledgement section is given below. This work has been edited in memorial of Salim Sahin and Emsal Sahin, Prof. Dr. Ayhan Mergen. We thank Istanbul Technical University and for the support by Scientific Research Projects Coordination Unit (BAP Unit) at Adana Alparslan Türkeş Science and Technology University with project number 22101001.
Structural and shielding effectiveness properties of (NiFe2O4/chopped strands) composites for 6.5–18 GHz applications
(Springer, 2024) Şahin, Ethem İlhan; İbrahim, Jamal-Eldin F. M.; Emek, Mehriban; Sinsoysal, Bahaddin; Amanzholova, Alina
In this research, a mixed oxide technique was employed to create composite materials comprising NiFe2O4-chopped strands, aimed at evaluating their structural properties and microwave shielding effectiveness. The composites, produced through a hot-pressing process with varying proportions of NiFe2O4 and chopped strands, were integrated with epoxy to enhance their shielding capabilities. X-ray diffraction confirmed the formation of single-phase NiFe2O4, free from secondary phases. Scanning electron microscopy analysis corroborated the presence of cubic crystalline NiFe2O4, without microstructural impurities. The microwave shielding performance of the composites was assessed within the 6.5-18 GHz frequency range using a network analyzer (NA), revealing a minimum shielding effectiveness of - 36.34 dB at 16.56 GHz for a 1.3 mm thick sample. These findings demonstrate the successful fabrication of NiFe2O4-chopped strands composites with tunable microwave shielding properties, achieved by adjusting the NiFe2O4 content, allowing for tailored performance across various frequency bands.
Correlation of proton conductivity and free volume in sulfonated polyether ether ketone electrolytes: a positron annihilation lifetime spectroscopy study
(Elsevier Ltd, 2025) Lahmuni, Muhammet; Yılmazoğlu, Mesut; Abacı, Ufuk; Çoban, Ozan; Yumak Yahşi, Ayse; Tav, Cumali; Yahşi, Uğur
Proton-conducting polymers play a pivotal role in clean energy technologies and various industrial applications, with a significant emphasis on enhancing energy efficiency and minimizing environmental impact. Sulfonated polyether ether ketone (SPEEK), which is renowned for its proton conductivity, has emerged as a key material in electrochemical processes, notably in proton exchange membrane (PEM) fuel cells. This study investigated the proton conductivity and dielectric behavior of SPEEK electrolytes at varying degree of sulfonation (DS) of 65% and 80%, correlating these properties with free volume profiles determined by positron annihilation lifetime spectroscopy (PALS). The SPEEK-65 and SPEEK-80 electrolytes were prepared via a controlled sulfonation process and characterized by FTIR, TGA, and SEM analyses. Proton conductivity and dielectric measurements were conducted at temperatures ranging from 300 to 370 K and frequencies ranging from 20 Hz to 1 MHz. The results revealed that SPEEK-80 exhibited a maximum proton conductivity of 3.4 × 10?2 S/m at 300 K and 1 MHz, which was significantly greater than the 4.38 × 10?3 S/m observed for SPEEK-65 under the same conditions. PALS analysis demonstrated a notable increase in free volume with increasing DS, with SPEEK-80 showing a higher o-Ps lifetime and intensity, indicating larger free volume sizes and fractions. These findings underscore the critical interplay between DS, free volume, and proton conductivity, offering insights into optimizing SPEEK-based electrolytes for advanced electrochemical applications.
Synthesis and characterization of metakaolin-based geopolymers doped with CRT waste glass for radiation shielding applications
(Elsevier, 2024) Al-Buriahi, M. S.; Kırkbınar, Mine; Alrowaili, Ziyad Awadh; Katubi, Khadijah Mohammedsaleh; Alsaiari, Norah Salem; Alalawi, Amani; Alomayrah, Nora; Olarinoye, I. O.
This study presents the influence of CRT glass on the gamma-ray interaction processes in metakaolin-based geopolymers. Four batches of G-CRT composites (namely, G, G-10CRT, G-20CRT, and G-30CRT, which represent geopolymer (G) samples doped with 0, 10, 20, and 30 wt% of CRT glass) were prepared using the cold hydrostatic press method. The mass attenuation coefficients of the prepared C-xCRT samples were computed using XCOM and FLUKA simulations for photons within the energy range of 15 keV-15 MeV. The density of the pristine geopolymer increased from about 1.86 g/cm3 3 to 2.09, 2.26, and 2.34 g/cm3 3 for G-10CRT, G-20CRT, and G-30CRT, respectively. The photon mass and linear attenuation coefficients of the geopolymers increased with CRT glass concentration. The half-value layer and mean free path were within the ranges 0.070-18.079 cm and 0.101-26.083 cm for G; 0.036-15.110 cm and 0.052-21.799 cm for G-10CRT; 0.024-13.197 cm and 0.014-19.039 cm for G-20CRT; and 0.018-12.074 and 0.026-17.419 cm for G-30CRT. The G-30CRT had the best gamma attenuating prowess in contrast to other G-xCRT. CRT-rich G-xCRT had a higher effective atomic number. For 10 mm thick geopolymer, the absorbed dose rates were 0.211 mu R/h, 0.66 mu R/h, 1.11 mu R/h, and 1.55 mu R/h for G, G-10CRT, G-20CRT, and G-30CRT, respectively, for 100 keV photons. The introduction of CRT glass into the geopolymer matrix improved their photon interaction cross-section. The geopolymers showed outstanding photon interaction ability compared to ordinary concrete and some shielding glasses at low photon energies. The CRT glass-doped geopolymer samples are useful for preparing radiation shielding concrete.
Development of hybrid actuator system for recovery of the model rockets
(Institute of Electrical and Electronics Engineers Inc., 2024) İpek, Gülhas; Dalkıran, Atılay; Dilibal, Savaş
Model rockets are the advanced mechatronic systems established through the design, manufacturing, and integration of the model-scale mechatronic sub-systems for a rocket mechanism capable of operating at low altitudes. The safe recovery and reusability of model rockets are prominent tasks to address. Various actuator systems are used in model rockets to solve the safe recovery problem by safely releasing and recovering the payloads that they carry at specific altitudes, allowing the rockets to be recovered. Traditionally, model rockets have employed recovery units powered by gunpowder. This research aims to design a novel hybrid actuator system integrating mechanical components with pressurized gas and servo motor components as an alternative to traditional gunpowder systems to enhance reliability and safety. The objective is to develop a prototype of a hybrid recovery actuator system using CO2 tubes and servo motors. The principle behind the designed recovery system relies on the release of CO2 gas, which facilitates the separation of the rocket motor body from the main body. This principle is based on the mechanism within the designed actuator system, which functions by releasing the potential energy stored in compressed springs. Servo motors triggered by signals from the rocket's flight computer release the springs, allowing the CO2 gas to escape. The released gas separates the rocket bodies, ensuring a safe descent. Within the scope of this research, the efficiency and effectiveness of the CO2 based hybrid recovery actuator system are evaluated through the production of a prototype. The experimental results unveiled that the development of the CO2 based hybrid recovery actuator system enables safe and successful recovery of model rockets. To achieve the timely release of the CO2 gas in the recovery system, the required pressure is determined via experimental studies for the separation of rocket bodies, ensuring a safe descent.
Study of the heat?mass transfer process considering the well?reservoir system in fractured reservoirs
(Geology and Geophysics Institute at Azerbaijan National Academy of Sciences (ANAS), 2023) Jalalov, G.; Rasulov, M.; Sinsoysal, Bahaddin
The theoretical study of oil field development processes and the creation of adequate technological schemes, taking into account the possible compound physical processes occurring in the field to ensure optimal exploitation of deposits, highlight the necessity of a complex scientific approach. Besides the geological-geophysical data required for the creation of technological schemes, obtaining the physical data of the deposit is one of the important factors. Obviously, much of these data come from wells drilled into the reservoir. The most important aspect of these studies is the investigation of the mass exchange and phase transition mechanisms of hydrocarbons, taking into account the pressure and temperature changes in the reservoir and the well during liquid filtration. In this paper, the effect of pressure and temperature changes during the processing of hydrocarbon deposits on exploitation indicators is examined by considering the well-reservoir system.

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