119 research outputs found
Cytopathologist-performed and ultrasound-guided fine needle aspiration cytology enhances diagnostic accuracy and avoids pitfalls: An overview of 20 years of personal experience with a selection of didactic cases
No full textOver the last few decades, fine needle aspiration cytology (FNA) has emerged as a SAFE (Simple, Accurate, Fast, Economical) diagnostic tool based on the morphologic evaluation of cells. The first and most important step in obtaining accurate results from FNA is to procure sufficient and representative material from the lesion and to appropriately transfer this material to the laboratory. Unfortunately, the most important aspect of this task occurs beyond the control of the cytopathologist, a key reason for obtaining unsatisfactory results with FNA. There is growing interest in the field of cytology in “cytopathologist-performed ultrasound (US)-guided FNA,” which has been reported to yield accurate results. The first author has been applying FNA in his own private cytopathology practice with a radiologist and under the guidance of US for more than 20 years. This study retrospectively reviews the utility of this practice. We present a selection of didactic examples under different headings that highlight the application of FNA by a cytopathologist, accompanied by US, under the guidance of a radiologist, in the form of an “outpatient FNA clinic.” The use of this technique enhances diagnostic accuracy and prevents pitfalls. The highlights of each case are also outlined as “take-home messages.”</jats:p
Cytology of hydatid cyst mimicking intra-abdominal sarcoma, diagnosed by fine-needle aspiration
No full textAccording to Sultan Süleymans Decree verb and noun affixes in Özbek Turkish
No full textSosyal Bilimler Enstitüsü, Türk Dili ve Edebiyatı Ana Bilim Dalı, Türk Dili Bilim DalıBu çalışmada, Özbek Türkçesindeki isim ve fiil çekim ekleri, "Süleyman Padişah'ning Hükmi" adlı eser esas alınarak incelenmiştir. Çalışmanın giriş bölümünde Özbek adının yapısı ve kökeni hakkında ileri sürülen değişik görüşlere yer verilmiştir. Özbek Türklerinin günümüze kadar vermiş oldukları mücadeleler, yaptıkları savaşlar ve kazandıkları zaferlerden bahsedildikten sonra bugünkü Özbekistan'ın coğrafî, siyasî, sosyal, kültürel ve ekonomik özellikleri hakkında bilgi vprilmiştir. "Özbek Türkçesi" başlığı altında, Özbek Türkçesinin konuşulduğu coğrafya ve ağız özellikleri üzerine yapılan tasnif çalışmaları, Türk dili içerisindeki yeri, fonetik ve morfolojik özelliklerine değinilhıiş, Özbek Türklerinin tarih boyunca kullandığı alfabeler ve bu alfabelerin özellikleri belirtilmiştir. Özbek Türklerinin tarihi ve Özbek Türkçesi ile ilgili bilgilerden sonra hazırlanan çalışmaya zemin olan "Süleyman Padişah'ning Hükmi" adlı eser hakkında bilgilere yer verilmiştir. Kadir Mirmuhamedav tarafından 1994 yılında Rusçadan çevrilmiş olan iki yüz kırk sayfalık bu kitap, Kiril alfabesiyle yazılmış olduğu için Lâjtin alfabesine çevrilmiştir. Bu çalışmada Özbek Türkçesindeki isim ve fiil çekim ekleri, mevcut gramer kitaplarındaki bilgiler ışığında ve incelenen "Süleyman Padişah'ning Hükmi" adlı eser örnek alınarak değerlendirilmiştir. Eklerin Eski Türkçeden Özbek Türkçesine gelinceye kad^r geçirdiği değişimler gösterilmiştir. Eklerin fonksiyonları, cümle içinde kurdukları ilgiler ve kelime içindeki kullanım şekilleri tespit edilmiş ve incelenen eserden örneklerle değerlendirilmiştir.In this study, tha noun and verb affixes are examined in Özbek Turkish according to tha work whic is called "Süleyman Padişah' ning Hükmi". In introduction of study, it was placed different opinion about the name and origin of Ozbek. After discussed Ozbek Turkish people's struggle, their wars, victories until today from their foundetion, also geographical, political, social, cultural and economical properties of Özbekistan in today were informed. Under the headline "Ozbek Turkish", classification studies which were made about parts of Ozbek Turkish and its accent properties, place in Turkish language, discussed phonetic and morphologic properties and also Ozbek Turkish alphabets and properties of these alphabets which were used in the course of history were specified. After Ozbek Turkish history and informatipn about Ozbek Turkish, it was placed about the main work "Süleyman Padîşah'ning Hükmi" and its author. This book which was translated by Qadir Mirmuhamedav in 1994, has 240 pages and because of writteh in Kiril Alphabet, it was translated Latin Alphabet. In this study, noun-verb termination in Ozbek Turkish was evaluated according to present grammar books and the work named "Süleyman Padişah'ning Hükmi". After showry variation of termination until coming from Old Turkish Ozbek Turkish. Functions of terminations the using from in word and meaning in sentence was stablised and from analysed work was evaludded with examples
Improving organizational citizenship behavior through trust building between supervisors and subordinates: A systematic review of evidence
No full textThis dissertation assessed the impact of trust between supervisors and subordinates on organizational citizenship behavior and examined individual characteristics engendering trust in a vertical relationship. Based on a systematic review of evidence, trust between a supervisor and a subordinate was shown to positively affect a subordinate’s individual-directed and organization-directed organizational citizenship behaviors. Building on this finding, the author further examined the individual characteristics that engendered trust between supervisors and subordinates. Available evidence was synthesized based on realist synthesis and Context-Intervention-Mechanism-Outcome (CIMO) logic. Ability, benevolence, and integrity were identified as interventions that enhance vertical trust while their degrees of significance varied depending on the context. The author identified trust propensity and reciprocity as mechanisms that enhance the effects of these interventions on vertical trust. This dissertation contributes to the research on OCB and vertical trust by developing a framework that shows the relationship between trust antecedents, trust engendering mechanisms, and organizational citizenship behavior. This framework provides an evidence-based process for improving supervisor-subordinate relations and facilitating the OCB potential of subordinates into extra-role performance. It also informs management practice as to how contexts such as experience level, competency concerns, industry type, role-related expectations, ethical standards, and relationship duration shape the role of individual trustworthiness characteristics.VERTICAL TRUST AND OCB 1
Improving Organizational Citizenship Behavior Through Trust Building Between Supervisors and Subordinates: A Systematic Review of Evidence
Omer F. Ozbek
A Dissertation
Submitted to the Graduate Faculty of
University of Maryland University College
in Partial Fulfillment of
The Requirements for the Degree of
Doctor of Management
Faculty Advisors
Deborah M. Wharff, D.M.
Sharon G. Hadary, Ph.D
Kathleen F. Edwards, Ph.D
April 25, 2014
VERTICAL TRUST AND OCB 2
Abstract
This dissertation assessed the impact of trust between supervisors and subordinates on organizational citizenship behavior and examined individual characteristics engendering trust in a vertical relationship. Based on a systematic review of evidence, trust between a supervisor and a subordinate was shown to positively affect a subordinate’s individual-directed and organization-directed organizational citizenship behaviors. Building on this finding, the author further examined the individual characteristics that engendered trust between supervisors and subordinates. Available evidence was synthesized based on realist synthesis and Context-Intervention-Mechanism-Outcome (CIMO) logic. Ability, benevolence, and integrity were identified as interventions that enhance vertical trust while their degrees of significance varied depending on the context. The author identified trust propensity and reciprocity as mechanisms that enhance the effects of these interventions on vertical trust. This dissertation contributes to the research on OCB and vertical trust by developing a framework that shows the relationship between trust antecedents, trust engendering mechanisms, and organizational citizenship behavior. This framework provides an evidence-based process for improving supervisor-subordinate relations and facilitating the OCB potential of subordinates into extra-role performance. It also informs management practice as to how contexts such as experience level, competency concerns, industry type, role-related expectations, ethical standards, and relationship duration shape the role of individual trustworthiness characteristics.
Keywords: Organizational Citizenship Behavior, OCB, OCBI, OCBO, Trust, Dyadic Relationship, Social Exchange, Supervisor-Subordinate, Ability, Integrity, Benevolence, Reciprocity, Trust Propensity, Systematic Review, Realist Synthesis, CIMO logic
VERTICAL TRUST AND OCB 3
Acknowledgements
Thanks to God for the health, wealth, wisdom, and faith He has given me to accomplish this journey. He is the most Gracious, the most Merciful, the Sustainer. May peace be upon the last Messenger, his predecessors, companions, and followers.
I want to extend my deepest thanks to my family, particularly my wife Havva and son Furkan, for their support, patience, and sacrifice during my doctoral education.
I would like to express my sincere gratitude to my dissertation advisory committee, Dr. Deborah Wharff, Dr. Sharon Hadary, and Dr. Kay Edwards, for their support, guidance, and enthusiasm. I would particularly like to thank my primary advisor Dr. Deborah Wharff for her valuable guidance, encouragement, and kind support in my journey to become a scholar practitioner. I would also like to thank Dr. John Sherlock for his expert guidance on methodology.
I would like to express my appreciation to my Expert Panel, Dr. Robert Liden, Dr. Kilic Kanat, and Dr. Mehmet Okur. Their feedback and insights significantly helped improve the quality of this dissertation. I would also like to extend a very special thanks to my boss Erol Cebeci for his support, encouragement, and understanding. I would also like to thank to my cohort and wish them success in their lives.
VERTICAL TRUST AND OCB 4
Table of Contents
Abstract .......................................................................................................................................... 2
Acknowledgements ......................................................................................................................... 3
Table of Contents ............................................................................................................................ 4
List of Tables ................................................................................................................................. 7
List of Figures ................................................................................................................................ 8
Chapter 1: Introduction and Overview of Relevant Literature ....................................................... 9
1.1 Statement and significance of the problem ............................................................................... 9
1.2 Leadership Domain and Level of Analysis ............................................................................. 12
1.3 Organizational Citizenship Behavior ...................................................................................... 14
1.4 Vertical Dyadic Trust .............................................................................................................. 15
1.5 Importance to Management .................................................................................................... 16
1.6 Propositions and Research Questions ..................................................................................... 19
1.7 Organization of the dissertation .............................................................................................. 20
Chapter 2: Research Methodology and Approach ........................................................................ 22
2.1 Introduction ............................................................................................................................. 22
2.2 Evidence-Based Movement .................................................................................................... 22
2.3 Systematic Reviews ................................................................................................................ 25
2.4 Identification of evidence ....................................................................................................... 27
2.5 Quality Appraisal of Evidence ................................................................................................ 29
2.6 Data Analysis & Realist Synthesis ......................................................................................... 31
2.7 Advisory Panel of Subject Matter Experts (SMEs) ................................................................ 33
2.8 Summary ................................................................................................................................ 35
Chapter 3: Systematic Review of Evidence .................................................................................. 36 VERTICAL TRUST AND OCB 5
3.1 Introduction ............................................................................................................................. 36
3.2. Discussion of Theoretical Lenses .......................................................................................... 37
3.2.1 Organizational citizenship behavior theory. ........................................................................ 37
3.2.2 Integrative model of trust. .................................................................................................... 41
3.2.3 Social exchange theory. ....................................................................................................... 44
3.3 Vertical Dyadic Trust’s relationship with Organizational Citizenship Behavior ................... 47
3.4 Critical Factors of the Subordinate’s Trust in the Supervisor................................................. 61
3.5 Critical Factors of the Supervisor’s Trust in a Subordinate .................................................... 69
3.6 Summary ................................................................................................................................ 75
Chapter 4: Analysis and Discussion ............................................................................................. 77
4.1 Introduction ............................................................................................................................. 77
4.2 The Relationship between Vertical Trust and Organizational Citizenship Behaviors ........... 79
4.3 Individual Characteristics as Interventions ............................................................................. 82
4.3.1 Ability and context. .............................................................................................................. 83
4.3.2 Benevolence and context. .................................................................................................... 87
4.3.3 Integrity and context. ........................................................................................................... 89
4.4 Moderator Variables as Enhancing Mechanisms .................................................................... 92
4.4.1 Trust propensity. .................................................................................................................. 93
4.4.2 Reciprocity. .......................................................................................................................... 95
4.5 Research Questions, Propositions, and Warrants in Light of Findings .................................. 99
4.6 Other Points of View ............................................................................................................ 100
4.7 Summary ............................................................................................................................... 102
Chapter 5: Conceptual Framework ............................................................................................. 104
5.1 Introduction ........................................................................................................................... 104
5.2 Underlying logic ................................................................................................................... 105 VERTICAL TRUST AND OCB 6
5.3 Theoretical underpinnings of contextual analysis................................................................. 107
5.4 Graphical display and explanation of the framework ........................................................... 108
5.5 Discussion of relevant theories ............................................................................................. 113
5.6 Summary ............................................................................................................................... 114
Chapter 6: Conclusions, Implications and Trends ...................................................................... 116
6.1 Introduction ........................................................................................................................... 116
6.2 Overall conclusions ............................................................................................................... 117
6.3 Implications for management ............................................................................................... 119
6.4 Implications of emerging trends ........................................................................................... 124
6.5 Limitations and areas for future research .............................................................................. 126
6.6 Summary ............................................................................................................................... 129
References .................................................................................................................................. 131
Appendix A: Related databases and their providers ................................................................... 150
Appendix B: Final version of the search string .......................................................................... 151
Appendix C: Inclusion and Exclusion criteria ............................................................................ 152
Appendix D: Search Results ....................................................................................................... 153
Appendix E: Quality Assessment Tool ....................................................................................... 154
Appendix F: Flow of documents................................................................................................. 156
Appendix G: Data Extraction Tool ............................................................................................. 157
Appendix H: Feedback from Subject Matter Experts ................................................................. 158 VERTICAL TRUST AND OCB 7
List of Tables
Table 1: List of Most Relevant Academic Journals ...................................................................... 29
Table 2: Expected Contribution of Subject Matter Experts ......................................................... 33
Table 3: Feedback from Subject Matter Experts .......................................................................... 34
Table 4: Dimensions of Organizational Citizenship Behaviors .................................................... 39
Table 5: Trust Antecedents and Their Definitions ........................................................................ 43
Table 6: Components of CIMO-Logic ....................................................................................... 106
VERTICAL TRUST AND OCB 8
List of Figures
Figure 1: Four Elements of Evidence-Based Management .......................................................... 24
Figure 2: Four Dimensions of Research Quality .......................................................................... 30
Figure 3: Intertwined Circles of the Supervisor’s Trust in the Subordinate ................................. 72
Figure 4: General Diagram of CIMO-Logic ............................................................................... 105
Figure 5: The Conceptual Framework ........................................................................................ 109
VERTICAL TRUST AND OCB 9
Chapter 1: Introduction and Overview of Relevant Literature
1.1 Statement and significance of the problem
Members of modern organizations establish and maintain vertical dyadic relationships in the role of supervisor or subordinate to accomplish organizational goals. The quality and dynamics of this relationship have been the subject of theoretical and empirical studies in social and behavioral sciences. Research has identified that supervisors develop differentiated relationships with their subordinates at the dyadic level (Brower, Schoorman, & Tan, 2000; Graen & Scandura, 1987; Gooty & Yammarino, 2011; Knoll & Gill, 2011) and the dynamics of this relationship significantly change the outcome of the relationship (Dirks & Ferrin, 2002; Kramer, 1999; Schoorman, Mayer, & Davis, 2007). Among the outcomes of the relationship, a subordinate’s altruism, helping behaviors, civic virtue, sportsmanship, and courtesy are categorized as organizational citizenship behaviors (OCBs) (Organ, 1988; Williams & Anderson, 1991). OCB is defined as “performance that supports the social and psychological environment in which task performance takes place” (Organ, 1997, p. 95) and has been recognized as a key contributor to productivity, profitability, turnover reduction, and customer satisfaction (Ilies, Nahrgang, Morgeson, 2007; Podsakoff, Whitining, Podsakoff, & Blume, 2009; Truckenbrodt, 2000). Further research has identified vertical trust between a supervisor and a subordinate as a significant factor for a subordinate’s OCB (Dirks & Ferrin, 2002; Kacmar, Bachrach, Harris, & Noble, 2012; Konovsky & Pugh, 1994; Pillai, Schriesheim, & Williams, 1999). Considering the accumulation of diverse yet independent studies on vertical trust and OCBs, there is a need for systematically reviewing the evidence to integrate supervisor and subordinate perspectives on vertical trust and evaluate how vertical trust relates to OCBs. The purpose of this dissertation is to assess the impact of trust between supervisors and subordinates on OCB and to examine VERTICAL TRUST AND OCB 10
individual characteristics engendering trust in a vertical dyadic relationship.
Besides seeking maximum performance on job-related tasks for which employees receive compensation, organizations are increasingly relying on discretionary employee efforts to improve organizational effectiveness (Kataria, Garg, & Rastogi, 2012). These discretionary behaviors are the basis for OCB, which support an organization’s social and psychological environment and create benefits for the organization as well as the individual displaying them. OCBs contribute to organizational success by enhancing managerial productivity, collaboration, and adaptation capacity, as well as reducing turnover and absenteeism (Kataria et al., 2013; Podsakoff, MacKenzie, Paine, & Bachrach, 2000). Individual-level benefits of OCB include achieving higher job performance ratings and priority in reward allocation decisions such as pay raises and promotions (Allen & Rush, 1998; Podsakoff et al., 2009). Although OCBs cannot be enforced as requirements of a job description or an employment contract, supervisors can enhance their employees’ OCBs through social exchange and relationship building. Trust is identified as a key relational resource, particularly in a dyadic relationship that fosters and encourages OCBs (Dirks & Ferrin, 2002; Kacmar, et al., 2012; Konovsky & Pugh, 1994; Pillai, et al., 1999).
Trust enhances the willingness to work together in today’s increasingly diverse workforce where people are less able to rely on common backgrounds or interpersonal similarity (Fulmer & Gelfand, 2012). Trust between supervisors and subordinates becomes particularly essential under high-risk, time-pressured, dynamic conditions (Burke, Sims, Lazzara, & Salas, 2007). Mutual trust facilitates cohesion and collaboration between a supervisor and a subordinate (Boies & Howell, 2006; Gilbert & Tang, 1998; Kramer, 2010; Uhl-Bien, 2003). High levels of trust by a subordinate in a supervisor have shown to improve communication and information VERTICAL TRUST AND OCB 11
sharing (Ferrin, Dirks, & Shah, 2006), performance (Dirks & Ferrin 2002; Shaw, 1997), job satisfaction (Gillespie &Mann, 2004) and decrease turnover (Dirks & Ferrin, 2001). Particularly, high levels of vertical trust have been shown to improve a subordinate’s individual-directed and organization-directed OCB (Deluga, 1994, Ilies et al., 2007; Scandura & Pellegrini, 2008). OCBs include altruism (Organ, 1990), interpersonal facilitation (Van Scotter & Motowidlo, 1996), and helping and cooperating with others (Bennett & Stamper, 2001; Graham & Van Dyne, 2006; Podsakoff, Ahearne, & MacKenzie, 1997). These behaviors are discretionary in nature such that they are not enforceable requirements of a job description or an employment contract. However, research has shown that these behaviors can lead to critical contributions to an organization by enhancing co-worker and supervisory productivity, reducing use of scarce resources in operational functions, strengthening the organization’s ability to retain the best talents, and improving the organization’s ability to adapt to changes in environment (Podsakoff et al., 2009).
On the other hand, lack of mutual trust is shown to reduce citizenship behaviors and lead to absenteeism and counterproductive behavior (Brower, Lester, Korsgaard, & Dineen, 2009; Colquitt, Scott, & LePine, 2007; Podsakoff, et al., 2009). Lack of trust between supervisors and subordinates increases the cost of doing business as both members of the dyad engage in self-protective actions and make provisions against opportunistic behavior by the other (Limerick & Cunnington, 1993). In addition, lack of trust experienced by either member of the vertical dyad reduces the positive outcomes of this relationship (Brower, et al., 2009), such as the willingness to take risks and innov
Design and analyses of porous concrete for safety applications
No full textIn an explosion taking place close to or inside a concrete structure, apart from the dangers of the explosive itself, the hazard due to the large debris originating from the concrete structure is an important threat. Protective structures with high probability to experience such extreme loadings during their service lives, such as protection walls outside important buildings or munition magazines for storing explosives, have to be designed to mitigate the effects of a probable explosion. With this goal, a PhD project was undertaken on designing and analyzing a cementitious material with sufficient static strength to carry the service loads and fractures into small-size fragments when subjected to an explosion. This thesis presents the design procedure of such a material, the experimental and numerical investigations and the results of the project. In the last decades, extensive research has been focused on understanding the behavior of concrete structures under extreme dynamic loadings. While most studies aim at designing materials that resist impact loading, the objective of this project was developing a cementitious material that is expected to fracture and disintegrate under impact. During the research, a sensitivity study was conducted on various forms of cementitious materials (Chapter 2). Porous concretes with enhanced strength, fracturing into small fragments when exposed to impact loading, were obtained and analyzed. In the process of modifying the porous concrete properties the main goal was to enhance the static strength while maintaining a high porosity. By modifying the mixture composition as well as the method of compaction, porous concretes with improved static strengths (at the range of 30-50 MPa) were produced as presented in detail in Chapter 3. In order to better understand the properties of the porous concretes produced, mechanical tests at macro and meso-scales were performed. Computer tomography, electron microscopy and X-ray diffraction analyses were also conducted to better explain the effective parameters which were summarized in Chapter 3. Among all the parameters that have been investigated, aggregate properties have the most significant effect on the mechanical properties of porous concrete. On the other hand, intense compaction in thin layers (to ensure good control of the production process), which directly affects the packing of the particles and the porosity, is essential to attain porous concretes with substantial strengths. The contribution of microsilica to the mechanical properties of porous concrete was not significant, even though the tests on the interfacial transition zone (ITZ) clearly showed that microsilica improved the strength of the ITZ phase. The reason for this „contradiction‟ was better explained by the CT scans of partially fractured samples. These scans revealed that in porous concretes crack patterns are very much influenced by the distinct porous structure and the aggregate skeleton. The cracks are forced to propagate into locations guided by the geometry of the present phases and the path does not always go through the weakest phase i.e. the ITZ. In the process of designing a material with desired dynamic performance, efficient dynamic testing techniques were highly required. In Chapter 4, dealing with the dynamic testing and evaluation of the experimental research, various experimental configurations were adapted or introduced for determining the dynamic response of porous concretes in a drop weight impact test. Different types of porous concretes and a mixture of normal concrete were subjected to drop weight impact tests. When the experimental configurations that have been used are compared, it can be concluded that stress gauge measurements have the advantage of direct measurement of the transmitted stress, while no analyses are needed afterwards to obtain the impact strength data. Among the other two monitoring and measuring techniques (LDV and high speed photography) that have been applied, LDV proved to be more accurate due to its higher sampling rate compared to high speed photography. It also has the advantage of being independent of factors such as the intensity of the light source. High speed photography, however, has its own advantage of also facilitating the visualization of the fracture process, which provides important qualitative information on the crack patterns. On the other hand, both techniques have the advantage of being non-contact methods. In the analyses of the drop weight impact test results, obtained using LDV and high-speed photography, the reverberation application of the impedance mismatch method was used. The analysis method proved to be very suitable to investigate the drop weight impact behavior of porous concretes. It also had the advantage of involving only the well-known dynamic impedance properties and the velocity measurements of the impactor, while the properties of the tested target specimen are not directly involved in the measurements and the analysis. The focus of the numerical part of the research was simulating and assessing the dynamic behavior of different porous concretes under impact loading. To achieve this goal, analyses were conducted both on real porous concretes and on fictitious (model) porous materials. The latter models were used to demonstrate better the individual factors affecting the porous concrete properties. In the research, explicit time integration was selected as the analysis method. For the realistic representation of the real concretes that were produced and tested, the aggregates present in the mixtures were directly determined through 3D computed tomography. A mesh generation program was developed for generating realistic finite element meshes. In the analyses, porous concrete was considered as a four-phase material consisting of aggregates, bulk cement paste, interfacial transition zones (ITZ) and meso-size air pores. When analyzing real porous concretes, the influences of the different parameters such as pore and aggregate size distributions and total porosity, are usually coupled. For distinguishing the sole effect of each parameter, virtual or model porous concretes were analyzed. The primary objectives of these analyses were computing the impact strength and examining the fragmentation behavior. The pore structures parameters are the most dominant factors affecting the mechanical properties of porous concretes. Therefore, model porous concretes having regularly and irregularly distributed circular pores of different radii and total porosity were analyzed. From the comparison of the impact responses of model porous concretes with different size pores, it could be concluded that for all porosities analyzed the impact strength of the concretes increased with decreasing pore size (at constant total porosity). It could also be concluded that for constant total porosity the sizes of the fragments that were formed drastically decreased when the pore size decreased. The results obtained from the analyses on the concretes with randomly distributed pores showed that for mixtures with larger pore sizes the scatter in impact strengths was larger. To understand the effect of aggregate size on the porous concrete properties, circular aggregate model porous concretes were analyzed. The results showed that the impact strengths of porous concretes with 8 mm and 4 mm particles (same porosity) were approximately the same, while the impact strength of the model porous concrete with 2 mm particles was lower. Reasons for this were explained in detail in Chapter 5: in different mixtures several factors influenced the results in opposite ways. In the numerical analyses of real porous concretes, the simulations were quite realistic. This result was achieved by applying proper finite element meshes resembling the actual porous concretes and accurate input data for the cementitious phases of the materials being quantified in the experiments at the meso-scale. Comparison of the peak values of the impact stress time histories showed that impact strengths of the samples obtained numerically (presented in Chapter 5) were in a good agreement with the experimental results. Pore and fragment size distributions of real porous concretes were also computed using the numerical models. This provided valuable information for better understanding of the fragmentation of the different mixtures. This thesis comprises experimental and numerical investigations performed on porous concretes meant to be used in safety applications. The results obtained from the enhanced strength porous concretes that have been produced were promising. The impact test monitoring methods proposed as well as the numerical analyses can be used in experimental and numerical investigation of the dynamic behavior of porous concretes
Contact lens-based expansion and transplantation of autologous epithelial progenitors for ocular surface reconstruction: Crossover control
No full text[No abstract available]Di Girolamo N, 2009, TRANSPLANTATION, V87, P1571, DOI 10.1097-TP.0b013e3181a4bbf2; Ozbek Z, 2006, CORNEA, V25, P245, DOI 10.1097-01.ico.0000176602.49258.ea; Parmar DN, 2006, AM J OPHTHALMOL, V141, P299, DOI 10.1016-j.ajo.2005.09.0080
A communication-driven method for enhancing user participation in the design process
No full textDesign processes generally try to align user requirements with design solutions. Communication gaps between designers and users, nevertheless, may lead to mismatches between intended user experience and eventual perception by end users. This study presents a communication-driven method for enhancing user participation in the design process and formally incorporating user feedback. The method identifies and resolves user experience discontinuities by eliciting and consolidating qualitative and quantitative user appraisals. Building on the Semantic Discontinuity Detection method, the method (i) integrates user feedback into an iterative design process, and (ii) uses virtual reality simulations for design communication to detect and resolve discontinuities. The discontinuity results are communicated to designers, for improving correspondence between design outcomes and user experiences. Revised designs are evaluated for improved alignment, indicating validation of the method. The results show that communication-centered design effectively reduces experience inconsistencies, increases the engagement of users, and improves design outcomes
Impact behavior of model porous concretes
No full textIn this work, findings of a numerical study performed to investigate the impact behavior of porous concrete, modeled as a four phase cementitious composite consisting of aggregates, cement paste, interfacial transition zones (ITZ) and air, are presented. The numerical analyses contributed to the process of designing a special type of concrete for safety purposes i.e. as a protective building material to be used in safety walls outside important buildings or munition magazines for storing explosives. In case of an explosion, large concrete fragments that are formed, cause a very important threat. Therefore, in the scope of a research project, designing a special type of concrete having sufficient strength, but fracturing into small fragments under impact loading was aimed. In the numerical analyses, model porous concretes, in which the amounts and properties of pores and aggregates could be varied individually, were used to see the sole effect of each parameter. According to the results, it was found that at constant total porosity, the impact strength increased with decreasing pore size while multiple fragmentation was observed. On the other hand, the impact strengths of porous concretes with different size aggregates (with constant total aggregate content and porosity) were approximately the same when no ITZ was defined. However, when ITZ was present, the impact strength was found to decrease as the aggregates were finer. This trend was also valid for the respective full concretes. Representative experimental results of porous concretes were also presented in order to support the numerical results.Accepted Author ManuscriptApplied MechanicsMaterials and Environmen
An Evaluation of Model-Free Control Strategies for Quadrotor Type Unmanned Aerial Vehicles
No full text3rd International Conference on Applied Automation and Industrial Diagnostics (ICAAID) -- SEP 25-27, 2019 -- Elazig, TURKEYThe present study addresses two representative model-free control strategies namely, model-free intelligent PID (i-PID) and type-2 fuzzy adaptive PID in control of a quadrotor type vertical take-off and landing (VTOL) unmanned aerial vehicle. The objectives of this study are i) to summarize the modeling and flight control methods of quadrotor in some classifications, ii) to investigate merits and demerits of model-free control strategies, iii) to compare the control performance in terms of some quantitative performance criteria. The results illustrate the performance of such methodologies applied to the quadrotor system.Ziane Achour Univ Djelfa,Firat Univ, Engn Fac,Djelfa Univ, Fac Sci & Technol, Appl Automat & Ind Diagnost Lab,Appl Automat & Ind Diagnost Lab,Algerian IEEE Sect,Turkey IEEE Sect,IEEE Ind Applicat Soc,IEEE,Djelfa Univ, Gas Turbine,Djelfa Univ, Lab Automatique Appliquee Diagnost IndScientific Research Unit of Adana Alparslan Trke Science and Technology University [18103030]This work is financially supported by the Scientific Research Unit of Adana Alparslan Trke Science and Technology University under the 18103030 project number.The author would like to give special thanks to Prof. M. O. Efe, Prof. C. Kasnakoglu, Prof. H. Mounier, and Dr. M. Onkol for fruitful discussion on this topic
Epigean amphipod fauna of Gonen Stream (western Anatolia, Turkey), with the description of Gammarus gonensis sp nov.
No full textGonen Stream, which is about 134 km in length, arises from the Ida Mountains near Balikesir and flows out near Misakca to the Sea of Marmara. In order to determine the freshwater amphipod species of Gonen Stream, 8 seasonal samplings were conducted between June 2010 and June 2012. Samplings were made at 16 stations located between the upper and lower parts of the stream. As a result of the study, 3 amphipod species were found, one of which is new to science: Gammarus gonensis sp. nov. The newly described species belongs to the Gammarus pulex- group. Gammarus gonensis resembles G. uludagi G. Karaman, 1975 by having long curled setae on the second gnathopods of the males. It differs from G. uludagi by having many long setae along the anterior margins of pereopods 5 to 7 in both sexes, and by having less setose peduncular segments of antenna 2. Some other characteristic features of the newly described species are also discussed, and detailed drawings of the extremities of holotype and allotype specimens are presented.Ege University Scientific Research FundEge University [2010/SUF/002]This study was financially supported by the Ege University Scientific Research Fund (Project No.: 2010/SUF/002). The author wishes to thank the project team for their help during field studies
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