Characteristics of Engineered Waste Materials Used for Road Subbase Layers

Seyhan Fırat,Sedef Dikmen,Gülgün Yılmaz,Jamal Mohamad Khatib 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.9

Coal fly ash (FA) and basic oxygen furnace (BOF) slag are the by-products of coal combustion in power stations and steel plants, respectively. The disposal of these wastes would require landfill space and can cause environmental pollution. In order to avoid disposal, the use of FA and BOF slag as sub-base material in highway pavement was investigated. The first part of this research was the characterization of FA and BOF in terms of their chemical and mineralogical compositions as well as the microstructural analysis. This is followed by the preparation of soil mixtures containing different proportions of kaolin, FA, BOF slag (0%, 15%, 20% and 25% by weight) and lime at a constant ratio (5%). Kaolin was used to represent the natural soil. The soil mixtures were cured for 1, 7 and 28 days and some were cured 56 days. At each curing age, the dry unit weight (dmax), the unconfined compressive strength (UCS) and California bearing ratio (CBR) were determined. X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques were also used to examine the changes in the phase-mineral composition and microstructure properties, respectively. The results show that the maximum dry unit weight values were observed in the mixture consisting of 25% FA, 15% BOF slag and 5% lime. The XRD analyses of kaolin soils containing, FA, BOF slag and lime exhibited the formation of hydrated products such as portlandite (C-H), calcium silicate hydrates (C-S-H) and calcium aluminium silicate hydrate (C-A-S-H), which increase with the age curing. According to results obtained, FA and BOF slag can be used in road base and sub-base materials.

Prevention of Occupational Diseases in Turkey: Deriving Lessons From Journey of Surveillance

Seyhan Şen,Güls¸ en Barlas,Selçuk Yakıs¸ tıran,_Ilknur G. Derin,Berna A. S¸ erifi,Ahmet Özlü,Lutgart Braeckman,Gert van der Laan,Frank van Dijk 한국산업안전보건공단 산업안전보건연구원 2019 Safety and health at work Vol.10 No.4

Introduction: To prevent and manage the societal and economic burden of occupational diseases (ODs), countries should develop strong prevention policies, health surveillance and registry systems. This study aims to contribute to the improvement of OD surveillance at national level as well as to identify priority actions in Turkey. Methods: The history and current status of occupational health studies were considered from the perspective of OD surveillance. Interpretative research was done through literature review on occupational health at national, regional and international level. Analyses were focused on countries’ experiences in policy development and practice, roles and responsibilities of institutions, multidisciplinary and intersectoral collaboration. OD surveillance models of Turkey, Belgium and the Netherlands were examined through exchange visits. Face-to-face interviews were conducted to explore the peculiarities of legislative and institutional structures, the best and worst practices, and approach principles. Results: Some countries are more focused on exploring OD trends through effective and cost-efficient researches, with particular attention to new and emerging ODs. Other countries try to reach every single case of OD for compensation and rehabilitation. Each practice has advantages and shortcomings, but they are not mutually exclusive, and thus an effective combination is possible. Conclusion: Effective surveillance and registry approaches play a key role in the prevention of ODs. A well-designed system enables monitoring and assessment of OD prevalence and trends, and adoption of preventive measures while improving the effectiveness of redressing and compensation. A robust surveillance does not only provide protection of workers’ health but also advances prevention of economic losses.

Applications of quasi power increasing sequences to infinite series

Hikmet Seyhan Ozarslan,Mehmet Oner Sakar,Bagdagul Kartal 한국전산응용수학회 2023 Journal of applied mathematics & informatics Vol.41 No.1

In the present paper, two theorems on absolute matrix summability of infinite series are generalized for the $\varphi-|A,p_n|_k$ summability method using quasi $\beta$-power increasing sequences instead of almost \linebreak increasing sequences.

Investigation of drag reduction performance of half NACA 0009 and 0012 airfoils placed over a trailer on the flow around truck-trailer

Mehmet Seyhan,Mustafa Sarioglu 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.7

The drag reduction performance of a half airfoil attached to a trailer and the roof fairing at different positions was experimentally investigated in a wind tunnel. Half airfoils have NACA 0009 and NACA 0012 cross-section and the roof fairing position is changed from -4.5 mm to +4.5 mm. Smoke wire and surface oil flow visualization were also performed to elucidate the flow characteristic around the truck-trailer with drag reduction devices. While the drag reduction rate of the truck trailer with half airfoil is up to 10 % higher than that of alone truck-trailer at all Reynolds number ranges, drag reduction of the truck trailer with the half airfoil and the roof fairing was exceeded 30 % as compared to the alone truck trailer. Drag coefficient results indicated that the half NACA 0009 and NACA 0012 airfoil has an almost similar trend at the zero-roof fairing position. Laminar separation bubble formation was observed on the surface of roof fairing with the help of surface oil flow visualization.

Prevention of Occupational Diseases in Turkey: Deriving Lessons From Journey of Surveillance

Sen, Seyhan,Barlas, GulSen,YakiStiran, Selcuk,Derin, ilknur G.,Serifi, Berna A.,Ozlu, Ahmet,Braeckman, lutgart,laan, Gert van der,Dijk, Frank van Occupational Safety and Health Research Institute 2019 Safety and health at work Vol.10 No.4

Introduction: To prevent and manage the societal and economic burden of occupational diseases (ODs), countries should develop strong prevention policies, health surveillance and registry systems. This study aims to contribute to the improvement of OD surveillance at national level as well as to identify priority actions in Turkey. Methods: The history and current status of occupational health studies were considered from the perspective of OD surveillance. Interpretative research was done through literature review on occupational health at national, regional and international level. Analyses were focused on countries' experiences in policy development and practice, roles and responsibilities of institutions, multidisciplinary and intersectoral collaboration. OD surveillance models of Turkey, Belgium and the Netherlands were examined through exchange visits. Face-to-face interviews were conducted to explore the peculiarities of legislative and institutional structures, the best and worst practices, and approach principles. Results: Some countries are more focused on exploring OD trends through effective and cost-efficient researches, with particular attention to new and emerging ODs. Other countries try to reach every single case of OD for compensation and rehabilitation. Each practice has advantages and shortcomings, but they are not mutually exclusive, and thus an effective combination is possible. Conclusion: Effective surveillance and registry approaches play a key role in the prevention of ODs. A well-designed system enables monitoring and assessment of OD prevalence and trends, and adoption of preventive measures while improving the effectiveness of redressing and compensation. A robust surveillance does not only provide protection of workers' health but also advances prevention of economic losses.

ON A NEW APPLICATION OF QUASI POWER INCREASING SEQUENCES

OZARSLAN, HIKMET SEYHAN The Korean Society for Computational and Applied M 2021 Journal of applied mathematics & informatics Vol.39 No.3

In the present paper, a theorem on 𝜑 - | C, 𝛼; 𝛿 |_k summability of an infinite series is obtained by using a quasi 𝛽-power increasing sequence.

An Application of Absolute Matrix Summability using Almost Increasing and δ-quasi-monotone Sequences

Ozarslan, Hikmet Seyhan Department of Mathematics 2019 Kyungpook mathematical journal Vol.59 No.2

In the present paper, absolute matrix summability of infinite series is studied. A new theorem concerning absolute matrix summability factors, which generalizes a known theorem dealing with absolute Riesz summability factors of infinite series, is proved using almost increasing and ${\delta}$-quasi-monotone sequences. Also, a result dealing with absolute $Ces{\grave{a}}ro$ summability is given.

Tools to Run Your Machine ( and Keep it Running )

David Lang,Seyhan Nuyan 한국펄프·종이공학회 1998 펄프종이기술국제세미나 Vol.25 No.-

The Evaluation of Personal Protective Equipment Usage Habit of Mining Employees Using Structural Equation Modeling

Kursunoglu, Nilufer,Onder, Seyhan,Onder, Mustafa Occupational Safety and Health Research Institute 2022 Safety and health at work Vol.13 No.2

Background: In occupational studies, it is a known situation that technical and organizational attempts are used to prevent occupational accidents. Especially in the mining sector, if these attempts cannot prevent occupational accidents, personal protective equipment (PPE) becomes a necessity. Thus, in this study, the main objective is to examine the effects of the variables on the use of PPE and identify important factors. Methods: A questionnaire was implemented and structural equation modeling was conducted to ascertain the significant factors affecting the PPE use of mining employees. The model includes the factors that ergonomics, the efficiency of PPE and employee training, and PPE usage habit. Results: The results indicate that ergonomics and employee training have no significant effect (p > 0.05) on the use of PPE. The efficiency of PPE has a statistically meaningful effect (p < 0.05) on the use of PPE. Various variables have been evaluated in previous studies. However, none of them examined the variables simultaneously. Conclusion: The developed model in the study enables to better focus on ergonomics and employee training in the PPE usage. The effectiveness of a PPE makes its use unavoidable. Emphasizing PPE effectiveness in OHS training and even showing them in practice will increase employees' PPE usage. The fact that a PPE with high effectiveness is also ergonomic means that it will be used at high rates by the employee.

The Effect of Running Water Sound Listened to Patients During Urodynamics on Anxiety and Urodynamic Parameters

Yeliz Çulha,Ezgi Seyhan Ak,Mehmet Gökhan Çulha 대한배뇨장애요실금학회 2023 International Neurourology Journal Vol.27 No.3

Purpose: This study was conducted to determine the effect of listening to the sound of running water during urodynamics on the patient’s anxiety and parameters in the pressure-flow study. Methods: The population of the study, which was planned in the nonrandomized experimental study design, consisted of patients who will undergo urodynamics in the Urology Department of a city hospital in Istanbul between September 2022 and January 2023, and the sample consisted of 60 patients, 30 of which were in the experimental group and 30 in the control group. During the pressure-flow study, the patients in the experimental group listened to the sound of running water from a smartphone, while the patients in the control group did not undergo any intervention during urodynamics. The level of anxiety in both groups before, during and after urodynamics was evaluated with the visual analogue scale. During the pressure-flow study, it was evaluated whether the patients emptied on command, and the maximum flow rate (Qmax) and the detrusor pressure at the maximum flow rate (PdetQmax) were measured. Bladder outlet obstruction index (PdetQmax–2Qmax) and bladder contractility index (Pdetqmax+5Qmax) were calculated using these values. Results: During the pressure-flow study, in the experimental group patients who listened to the sound of running water from a smartphone; anxiety level mean scores during and after urodynamics were found to be statistically significantly lower than the control group patients (P<0.001). The mean bladder contractility index score in the experimental group patients was statistically significantly higher than the control group patients (P<0.001), and the cases of urinating with a catheter during the pressure-flow study were statistically significantly higher than the control group patients (P<0.001). Conclusions: Listening to the sound of running water during urodynamics had a positive effect on reducing anxiety in patients and micturating during pressure-flow study.