WoS İndeksli Yayınlar Koleksiyonu

Bu koleksiyon için kalıcı URI

https://hdl.handle.net/11501/8

Listeleniyor 1 - 20 / 511

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.
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).
Afghan women are under threat from the Taliban: a great test of the Turkish government and the courts
(Oxford University Press, 2024) Kaya, Hülya
This article examines how Türkiye evaluates the protection requirements of Afghan women fleeing from persecution in Afghanistan. It considers whether Türkiye grants refugee status to Afghan women as members of a 'particular social group' or on other Refugee Convention grounds. It analyses the jurisprudence of Türkiye's Administrative Courts and Regional Administrative Courts concerning international protection claims lodged by Afghan women between August 2021 and June 2023 to determine whether Türkiye follows a gender-sensitive interpretation of the Refugee Convention and respects the principle of non-refoulement.
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.
Reduced resting and task-related alpha activity in mine workers: implications for occupational health and neurodegenerative risk
(Elsevier B.V., 2024) Çelik, Samet; Yıldırım, Ebru; Güntekin, Bahar
Underground mine workers face many risk factors at work sites that are known to affect the neural system. Observational studies report that these risk factors precede neuromuscular and neurodegenerative disorders, especially in old-age miners. Neurodegenerative disorders have electrophysiological, anatomical, and functional changes long before symptoms are seen in older adults. Therefore, this study investigated whether risks faced by miners at young ages were reflected in electrophysiological signals. Twenty-one underground miners and twenty-two above-ground workers matched with them in terms of age, education, and working duration were included in this study. Participants were recorded with a 20-channel EEG during the resting-state (eyes open and closed; EO-EC) and the perception of the International Affective Picture System Paradigm (IAPS). Time-frequency analyses were performed for alpha frequency. Rs-EEG results showed a statistically significant difference in alpha power between the EO and EC states in the control group. However, there was no statistical difference in alpha power between these two conditions in the miners. Additionally, we noted a more pronounced decrease in alpha responses in the posterior region during EC in the miners. The group's main effects were statistically significant in event-related alpha responses during emotional responses. Accordingly, event-related alpha responses of the miner group were lower than the control group in terms of both power spectrum and phase-locking. Underground mine workers are cognitively and emotionally affected by risks in the work environment. Electrophysiological changes seen in young underground workers may be a harbinger of neurodegenerative disorders in miners' old age. Our research findings may lead to the development of occupational neuroscience, social policies, and worker health, which are necessary to improve working conditions for mineworkers.
Evaluation of the use of vacuum-dehydrated minced meat in beef patty production
(Multidisciplinary Digital Publishing Institute (MDPI), 2024) Başlar, Mehmet; Yalınkılıç, Barış; Erol, Kübra Feyza; İrkilmez, Mustafa Ümit
This study aimed to determine the usage potential of vacuum-dehydrated ground beef in beef patty production. First, the fresh ground beef was dehydrated in vacuum dryers at 25, 35, and 45 °C for dehydration kinetics and color change. Then, the vacuum-dehydrated ground beef was rehydrated, and three different beef patties were separately produced using fresh ground beef, the rehydrated ground beef, and a mixture of the two (1:1). According to the results, the dehydration significantly decreased the L*, a*, and b* values of ground beef; however, after rehydration, the L* and b* values were not significantly different from the control values. The cooking loss for beef patties produced with rehydrated ground beef was higher than the control. However, there was no significant difference in the sensory of the beef patties among the treatments. In conclusion, there is potential for using vacuum-dehydrated ground beef in beef patty production.
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.
From “Criminal Citizens” to “Traitors”: The last of the Kurdish Bandits in Modern Turkey, 1950–1970
(University of Toronto Press, 2024) Özcan, Ahmet
The mass banditry that emerged in Turkey's Kurdish regions between 1950 and 1970 was labelled a "national problem" in state discourse. Banditry and bandits were thus an integral part of the Turkish nation-state building process and the politico-moral economy of the region. Turkish state policies with regard to banditry, after the transformation of bandits from "criminal citizens" into "traitors" in state discourse, culminated in massive military operations to disarm and suppress the peoples of these regions. This last period of Kurdish banditry, the result of the destabilization of traditional Kurdish society, was a source of political contention between the state elite and Kurdish communities.
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.
The relationship between sleep quality and posture: a study on university students
(Multidisciplinary Digital Publishing Institute (MDPI), 2024) Badau, Adela; Badau, Dana; Şarvan Cengiz, Şebnem; Coşkun, Ebrar Şevval
The aim of this study is to investigate body posture, physical exercises, head–neck relationship, and sleep quality among university students. A total of 96 students, with an average age of 20.86 ± 1.24 years and an average BMI of 23.41 ± 2.56, voluntarily participated in the study. The REEDCO Posture Evaluation (RPE) was used to assess the participants’ body posture scores. Head and neck measurements were taken using the Apecs-AI Posture Evaluation and Correction System® (Apecs Posture Analysis Pro Plus Version 8.2.6). Sleep quality was measured using the Pittsburgh Sleep Quality Index (PSQI). Pearson correlation analysis indicated that increased caffeine consumption was associated with poorer sleep quality (r = 0.267, p < 0.05). Additionally, increased participation in physical activities was associated with improved sleep quality, with those engaging in sports having better sleep quality scores (r = ?0.278, p < 0.05). As physical activity increased, REEDCO scores decreased (r = ?0.423, p < 0.05), while scores for right head (r = 0.210, p < 0.05) and left head (r = 0.247, p < 0.05) increased. Significant negative correlations were found between REEDCO scores and right head (r = ?0.296, p < 0.05) and left head (r = ?0.463, p < 0.05) scores. In conclusion, due to the limited number of studies investigating head–neck relationships and sleep quality, definitive conclusions cannot be drawn; further and more comprehensive research is needed.
Search for a scalar or pseudoscalar dilepton resonance produced in association with a massive vector boson or top quark-antiquark pair in multilepton events at √𝑠 =13 TeV
(American Physical Society, 2024) Tumasyan, A.; Adam, W.; Andrejkovic, J. W.; Bergauer, T.; Chatterjee, S.; Damanakis, K.; Dragicevic, M.
A search for beyond the standard model spin-0 bosons, phi, that decay into pairs of electrons, muons, or tau leptons is presented. The search targets the associated production of such bosons with a W or Z gauge boson, or a top quark-antiquark pair, and uses events with three or four charged leptons, including hadronically decaying tau leptons. The proton-proton collision data set used in the analysis was collected at the LHC from 2016 to 2018 at a center-of-mass energy of 13 TeV, and corresponds to an integrated luminosity of 138 fb(-1). The observations are consistent with the predictions from standard model processes. Upper limits are placed on the product of cross sections and branching fractions of such new particles over the mass range of 15 to 350 GeV with scalar, pseudoscalar, or Higgs-boson-like couplings, as well as on the product of coupling parameters and branching fractions. Several model-dependent exclusion limits are also presented. For a Higgs-boson-like phi model, limits are set on the mixing angle of the Higgs boson with the phi boson. For the associated production of a phi boson with a top quark-antiquark pair, limits are set on the coupling to top quarks. Finally, limits are set for the first time on a fermiophilic dilaton-like model with scalar couplings and a fermiophilic axion-like model with pseudoscalar couplings.
Measurement of simplified template cross sections of the Higgs boson produced in association with W or Z bosons in the H → bb decay channel in proton-proton collisions at √s=13 TeV
(American Physical Society, 2024) Tumasyan, A.; Adam, W.; Andrejkovic, J. W.; Bergauer, T.; Chatterjee, S.; Damanakis, K.; Dragicevic, M.
Differential cross sections are measured for the standard model Higgs boson produced in association with vector bosons (Formula Presented, Formula Presented) and decaying to a pair of Formula Presented quarks. Measurements are performed within the framework of the simplified template cross sections. The analysis relies on the leptonic decays of the Formula Presented and Formula Presented bosons, resulting in final states with 0, 1, or 2 electrons or muons. The Higgs boson candidates are either reconstructed from pairs of resolved Formula Presented-tagged jets, or from single large-radius jets containing the particles arising from two Formula Presented quarks. Proton-proton collision data at Formula Presented, collected by the CMS experiment in 2016-2018 and corresponding to a total integrated luminosity of Formula Presented, are analyzed. The inclusive signal strength, defined as the product of the observed production cross section and branching fraction relative to the standard model expectation, combining all analysis categories, is found to be Formula Presented. This corresponds to an observed (expected) significance of 6.3 (5.6) standard deviations.

Güncel Gönderiler