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From Walking to Running: A Comprehensive Clock Torque Actuated SLIP Framework for Trotting in Quadrupedal Locomotion
No full textThis paper presents a template-based control method for achieving diverse trotting motions in quadrupedal systems, with a focus on smooth transitions between walking trot, regular trot, and flying (running) trot. First, we extend the Clock Torque Actuated Spring-Loaded Inverted Pendulum (CT-SLIP) template to three dimensions, creating a comprehensive control framework. A template-based control strategy is then developed to compute joint torques for stable locomotion, along with a detailed approach for transitioning between gaits. To enable the flight phase in the running trot, a projectile motion model is incorporated into the template. For improved turning, we implement a yaw control method that rotates the swing foot plane to enhance stability, enabling higher turning rates while maintaining steady forward motion and balance. To further enhance locomotion stability and performance, a Whole-Body Controller (WBC) is integrated. The proposed method is implemented and rigorously evaluated in the MuJoCo simulator, with experiments testing gait transitions and disturbance rejection. Additionally, comparative studies assess the impacts of both swing foot plane rotation and the WBC on overall system performance. Furthermore, the approach is validated through real hardware experiments on Unitree GO1 quadrupedal robot, successfully demonstrating smooth gait transitions, stable locomotion, and practical applicability in real-world scenarios
A Comprehensive Assessment of Heavy Metal Contamination in Chinese Lake Sediments and Submerged Macrophyte Responses: Multi-Scale Impacts, Accumulation Capacity and Tolerance Mechanisms
No full textAlthough considerable research has examined the effects of heavy metals on submerged macrophytes, a comprehensive review addressing individual, population and community perspectives is lacking. This review first summarises the current status of heavy metal contamination in aquatic sediments in China. It then provides an in-depth analysis of heavy metal uptake, transport and accumulation in submerged macrophytes, as well as their broader ecological impacts across multiple scales. Additionally, we investigate the metal accumulation capacities of submerged macrophytes and examine their tolerance mechanisms. The findings underscore the severe contamination of aquatic ecosystems by heavy metals in sediments and reveal their multi-scale impacts on submerged macrophytes. At the individual level, heavy metals disrupt cellular functions, impairing photosynthesis, respiration and overall metabolic balance. Over time, these effects may influence population dynamics. Species-specific differences were observed in heavy metal accumulation and tolerance mechanisms, including variations in metal sequestration, antioxidant activation and phytochelatin production. Consequently, heavy metal pollution may further alter the submerged macrophyte community composition. This study identifies heavy metal pollution as a critical global issue, posing threats to submerged macrophytes across multiple ecological levels. Understanding its role in macrophyte decline is essential for ecosystem conservation. Additionally, our findings offer valuable insights into selecting heavy metal-tolerant species to facilitate both macrophyte recovery and sediment remediation, thereby contributing to the sustainable management of aquatic ecosystems
Experimental deduction of restitution coefficients of different sand sizes in an inertial particle separator system
No full textRotorcraft engines frequently operate in harsh environments, ingesting contaminants like sand, dust, rain, and hail, which degrade performance and reduce lifespan. Inertial Particle Separator (IPS) systems are commonly utilized in gas turbine engines, which force particles separated by their inertia. Separated sand value is influenced by various factors, including airflow rate, particle features, surface profile and properties. The current study focuses on the deduction of the Coefficient of Restitution (COR) and its impact on target surfaces under various condition to understand the particle-wall interaction in detail. The tangential and normal components of COR are key determinants of IPS efficiency. A previous study validated aerodynamics and measured separation efficiency in an engine-like test rig. Therefore, the current study aims to experimentally investigate the trajectories of sand particle of varying sizes within an IPS system and estimate their respective COR values. The obtained COR values are intended to be used as input for modelling wall interactions in numerical analyses. The article provides a detailed description of the experimental setup, methodology for COR calculation, and the wall interactions of particles of different sizes. Results indicate that smaller particles, accelerated by airflow, impact the IPS outer dome at farther points, while larger particles experience multiple collisions near the inlet, losing momentum. Smaller particles follow airflow due to aerodynamic forces, whereas larger particles, dominated by inertia, deviate from the flow
Reimagining urban science for global sustainability: Five strategic research areas
No full textNon-technical summary Cities, as complex systems, are faced with increasingly diverse and connected challenges across social, economic, environmental, and health domains. To help cities address these challenges, the Future Earth Urban Knowledge-Action Network developed a cross-disciplinary urban research agenda through expert elicitations and extensive consultation. Five research themes to guide urban sustainability research were identified including: (1) advancing urban sustainability transformations, (2) ensuring equity, (3) boosting innovation in low to lower-middle income countries, (4) managing complexity and systemic risks, and (5) navigating environmental change. Advancing this agenda will require collaboration across disciplines and geographies, transdisciplinary coproduction, and enhanced support to urban science. Technical Abstract Cities and urban regions are at the forefront of transformations toward global sustainability. As urbanization accelerates, there is increasing demand for cities to play multiple, complex and synthetic roles across social and environmental domains within and beyond their boundaries, for example driving economic development while mitigating and adapting to global environmental changes. To help cities in meeting this challenge, urban science, a rapidly growing field that includes inter- and transdisciplinary research, needs to expand and evolve, with clear priorities. Combining expert elicitation and community consultation, the Future Earth Urban Knowledge-Action Network developed a strategic research agenda for urban science for the next decade. The urban science research agenda describes five critical research themes for scientific advances: (1) accelerate urban sustainability transformations, (2) ensure equity and inclusivity, (3) amplify innovation from the low to lower-middle income countries, (4) negotiate complexity and systemic risks, and (5) navigate environmental change. Under each research theme, we review the state of the art, identify remaining gaps, and outline key research questions needing to be addressed to advance science toward urban transformations. Interconnections across, and enabling conditions to advance, these priority research themes are discussed. Social media summary Globally co-designed urban research agenda reveals pressing priorities for sustainability and resilience
Characterization of PCM melting behavior in a cavity including the effect of forced convection
No full textEnhancing heat transfer efficiency is crucial for improving the performance of systems designed for heat dissipation and thermal storage. Phase change materials (PCMs) offer favorable thermal characteristics but are hindered by inherently slow melting rates, a limitation this study seeks to address. This study introduces a novel approach that utilizes mechanical mixing to induce forced convection within a PCM-filled cavity. Experimental investigations were performed, where forced convection was introduced through liquid mixing at rotational speeds of 5, 25, and 100 rpm. For numerical studies, the enthalpy–porosity method, incorporating the Boussinesq approximation, is used. Experimental findings indicate that higher rotational speeds shorten the melting duration by up to 22 % (reducing it to 32 h) and increase the final liquid fraction by approximately 14 %, enabling complete melting compared with the non-rotating case. Moreover, mixing effectively reduced internal temperature gradients, lowering the maximum temperature from 68 °C to 45 °C and promoting a more uniform thermal distribution. At lower rotational speeds, the melting duration decreased by only about 10 %, with negligible impact on the final liquid fraction. The heat generation rate also strongly influenced melting performance. Experimental and validated numerical results, obtained with a Cmush value of 10⁶, showed acceptable agreement. Both approaches confirmed that at 40 W, 86 % of the PCM melted within 43 h, whereas at 20 W only 26 % melted in the same period. These findings establish mechanical mixing as a practical and effective strategy to overcome PCM’s slow melting limitation, thereby enhancing the applicability of PCMs in thermal management systems
HÜKÜMET YAPILARININ KENTSEL VE MİMARİ TASARIMI ÜZERİNE BİR İNCELEME: ANKARA’DA İNÖNÜ VE DUMLUPINAR BULVARLARI
No full textBased on the premise that government buildings are representative of the public architecture in a country, and they greatly contribute to shaping the identity of a capital city, the present thesis examines the government buildings in Ankara, the capital of the Turkish Republic, through their changing relation with the urban context, and their public, symbolic, and functional dimensions. The thesis study focuses particularly on how the architectural and urban qualities of the government buildings in Ankara have changed over time. In this scope, it explores the effects of this change on the development of the capital city and the underlying factors driving this transformation. The political and ideological context of the periods in which the government buildings have been produced, the architectural and urban design approaches adopted, their designers’ attitude, and the design processes are examined, with the objective to offer a critical assessment of how these structures are conceived and produced today.
This study adopts a methodological approach that categorizes topics along spatial, periodic, and methodological dimensions. In this scope, the government buildings constructed on Dumlupınar Boulevard after 2010 are examined in detail, based on the analyses of the architectural and urban characteristics of the selected buildings. The findings are evaluated in relation to the factors determining the architectural and urban aspects of government buildings. These findings primarily reveal the effects of the changing urban planning approach that has determined the urban context in which the buildings are built, characterized by a car-oriented, linear urban development, a piecemeal planning approach, and a lack of urban design. These factors influence the urban, formal and functional organization of the studied buildings that are mostly isolated within their parcels, which restrains their public use and accessibility, breaking their visual and spatial relationship with the public space as well as with each other. It is seen that while the architectural approach to the design of the government structures is partly shaped by the political and ideological orientations of the period; the changing methods in the acquisition of these public building projects have also been effective in shaping the built environment.Hükümet yapılarının bir ülkedeki kamu mimarisinin temsilcisi olduğu ve bir başkentin kimliğinin şekillenmesinde önemli bir rol oynadığı öncüllerinden yola çıkan bu tez, Türkiye Cumhuriyeti’nin başkenti Ankara’da bulunan hükümet yapılarını, kentsel bağlamla değişen ilişkileri ile, kamusal, sembolik ve işlevsel boyutları açısından incelemektedir. Bu tez çalışması, özellikle Ankara’daki hükümet yapılarının mimari ve kentsel niteliklerinin zaman içinde nasıl değiştiğine odaklanmakta; bu kapsamda, söz konusu değişimin başkentin gelişimi üzerindeki etkilerini ve bu dönüşümü yönlendiren temel faktörleri araştırmaktadır. Hükümet yapılarının üretildiği dönemlerin siyasal ve ideolojik bağlamı, planlama kararları, benimsenen mimari ve kentsel tasarım yaklaşımları, tasarımcılarının tutumları ve tasarım süreçleri incelenerek, bu binaların günümüzde nasıl ele alındığına, tasarlandığına ve üretildiğine ilişkin eleştirel bir değerlendirme yapılmaktadır.
Bu çalışma, konuları mekânsal, dönemsel ve yöntemsel boyutları üzerinden kategorize eden metodolojik bir yaklaşım benimsemiştir. Bu çerçevede, Dumlupınar Bulvarı üzerinde 2010 yılından sonra inşa edilen hükümet yapıları, seçilen örneklerin mimari ve kentsel özelliklerini çözümleyen analizlere dayanılarak ayrıntılı biçimde ele alınmıştır. Araştırmanın bulguları, hükümet yapılarının mimari ve kentsel niteliklerini belirleyen etkenlerle ilişkilendirilerek değerlendirilmiştir. Bu bulgular öncelikle, değişen kentsel planlama yaklaşımı doğrultusunda şekillenen, otomobil odaklı, doğrusal bir kentsel gelişim ile karakterize edilen kentsel bağlamın ve kentsel tasarım eksikliğinden kaynaklanan parçacıl planlama anlayışının etkilerini ortaya koymaktadır. Bu faktörler, çoğunlukla kendi parselleri içinde büyük boşluklar içerisinde yalıtılmış olan ve bu nedenle kamusal kullanımı ve erişilebilirliği kısıtlanan yapıların kentsel, biçimsel ve işlevsel organizasyonunu etkilemekte; bu durum, yapıların kamusal alanla ve birbirleriyle olan görsel ve mekânsal ilişkilerini koparmaktadır. Hükümet yapılarının tasarımına ilişkin mimari yaklaşımın kısmen dönemin ideolojik yönelimlerinden ve politikalarından etkilendiği; projelerin elde edilmesinde kullanılan yöntemlerin değişiminin de yapılı çevrenin biçimlenmesinde etkili olduğu belirlenmiştir.Ph.D. - Doctoral Progra
Intraguild Predation Is Insufficiently Mitigated by Complex-Structured Aquatic Vegetation
No full textIntraguild predation (IGP) occurs when one predator species consumes another species with whom it also competes for shared prey. IGP is widely believed to reduce prey suppression. In terrestrial ecosystems, structurally complex habitats may lessen IGP by offering refuge to intermediate predators. However, whether submerged macrophytes in shallow lakes could mitigate such antagonistic interactions remains largely unexplored. We examined the interactive impact of two aquatic predators, fish (Pelteobagrus fulvidraco, intraguild predator) and shrimp (Exopalaemon modestus, intraguild prey), on the biomass and assimilation of zooplankton prey in vegetation-sparse and vegetation-dense habitats in outdoor mesocosms. Relative to the shrimp-alone treatment, the presence of both predators resulted in a higher average zooplankton biomass in both simple and complex vegetation habitats. This suggests that IGP between the two predator species alleviated predation pressure on the zooplankton community when compared to the shrimp-alone mesocosms. However, no significant predator-macrophyte interactions were detected, suggesting that the strength of IGP was not significantly affected by habitat vegetation complexity. Evidence from zooplankton dietary markers (fatty acids) and associated carbon stable isotopes further substantiated that vegetation complexity did not significantly affect the assimilation of zooplankton by predators. Additionally, vegetation complexity had no significant effect on chlorophyll a concentrations. The results demonstrate that the strength of IGP was not substantially influenced by habitat vegetation complexity. Our findings have implications for food webs and predator–prey dynamics within aquatic systems. Thus, when implementing biomanipulation efforts aimed at combating eutrophication by enhancing herbivory on phytoplankton and promoting the resurgence of submerged macrophytes, both the quantity and diversity of predator assemblages, as well as the scale effects of submerged macrophytes, should be considered
Mimari Bildung Üzerine: Bir Model Sözlük ve Operasyonel Çatkı
No full textThis thesis is grounded in the premise that architecture is knowledge production encompassing cultural, political, and material dimensions. Yet many concepts central to this understanding have been erased or misused in modern and postmodern debates, often remaining overlooked. Addressing this requires a renewed terminology that revisits neglected strands of architectural theory to reframe diverse approaches to architectural knowledge-making. Accordingly, the framework builds on the nineteenth-century shift from “being” to “becoming”, within which the German concept of Bildung, encompassing “formation”, “culture”, and “education”, is claimed as both a theoretical and operative lens. Despite its foundational role in nineteenth-century art and aesthetics, Bildung has remained underexplored in architectural discourse. Intellectual perspectives approached it as subjective, historical, natural, and pedagogical; defined architecturally, however, it can further enable critical re-evaluations of the concept. In this regard, the research advances two arguments. First, strands of architectural theory over the past two centuries reveal recurring “reflexive doubles” that mirror the conceptual framework of Bildung, offering a means to define it in architectural terms. The thesis constructs a model glossary around doubles such as “artform and coreform”, “scenographical and technological”, and “shape and form”. Second, the interplay of plural understandings of Bildung offers an operational framework for architecture, defining three categories of creative processes: Imitative Bildung, Formative Bildung, and Reflexive Bildung. Treating earlier theories as active sites for generating new connections, this thesis contributes to the evolving theory of making by reactivating forgotten strands of architectural theory and proposing an expandable set of operations.Bu tez, mimarlığın kültürel, politik ve maddi boyutları kapsayan bir bilgi üretim biçimi olduğu öncülüne dayanmaktadır. Ancak bu anlayışa temel oluşturan birçok kavram, modern ve postmodern tartışmalarda göz ardı edilmiş ya da yanlış yorumlanmıştır. Bu durumu ele almak, ihmal edilmiş kuramsal izlekleri ve mimari bilgi üretimindeki farklı yaklaşımları çerçeveleyen bir terminoloji geliştirmeyi gerektirir. Bu bağlamda tez, on dokuzuncu yüzyılda “varlık”tan “oluş”a gerçekleşen dönüşüm içinde tanımlanmış, “oluşum”, “kültür” ve “eğitim” anlamlarını içeren Alman kökenli Bildung kavramını hem kuramsal hem de operatif bir çerçeve olarak ele alınmaktadır. Bildung, on dokuzuncu yüzyıl sanat ve estetiğinde kurucu bir rol oynamasına rağmen mimarlık söyleminde büyük ölçüde göz ardı edilmiştir. Entelektüel yaklaşımlar, kavramı öznel, tarihsel, doğal ve pedagojik olarak ele almıştır; ancak mimari olarak tanımlandığında, kavramın eleştirel biçimde yeniden değerlendirilmesine olanak tanıyabilir. Bu bağlamda tez, iki temel tartışma ortaya koyar. İlk tartışma, son iki yüzyılın mimarlık kuramındaki izleklerin, tarihsel kökleri on dokuzuncu yüzyıl öncül düşüncesine dayanan ‘öz-düşünümsel çift terimler’ üzerinden inşa edildiği ve Bildung’un mimari bağlamda tanımlanmasını mümkün kılan bir kuramsal çerçeve sunduğudur. Bu tartışma, “sanat-form ve öz-form”, “skenografik ve teknolojik” ve de “şekil ve form” gibi çift kavramlar etrafında bir model sözlük oluşturur. İkinci tartışma ise, Bildung’un çoğul yorumlarının mimarlık için operatif bir mantık sunduğudur. Bu bağlamda üç kategori yorumlanır: taklitsel Bildung , oluşumsal Bildung, ve öz-düşünümsel Bildung. Sonuç olarak, tarihsel kuramsal çerçeveleri yeni ilişkiler üretmek için etkin düşünsel alanlar olarak değerlendiren bu tez, mimari yapma kuramına katkıda bulunur ve genişletilebilir bir operasyonlar dizisi önerir.Ph.D. - Doctoral Progra
Anne disiplini, kültür ve duyusal işleme duyarlılığı: Türkiye ve İran’da çocukların utanma ve suçluluk eğilimlerinin kültürlerarası incelemesi
No full textThis cross-cultural study examined how maternal disciplinary practices, maternal self-construals, children's sensory processing sensitivity (SPS), and perceived normativeness of disciplinary practices relate to children’s shame- and guilt-proneness in Türkiye and Iran, two culturally similar societies undergoing distinct social transitions. Participants consisted of 344 mother-child dyads (174 from Turkey, 170 from Iran), with children aged 9-10. Mothers completed questionnaires on self-construal and their child’s SPS, which included the dimensions of overreaction to stimuli and depth of processing. Children reported on their mother’s discipline, perceived normativeness of these practices, and their own shame- and guilt-proneness. Turkish mothers were perceived to use power assertion, love withdrawal, and induction more frequently than Iranian mothers and reported higher levels of individuated and balanced self-construals. The conducted hierarchical regressions revealed that love withdrawal predicted higher shame-proneness in both countries, while other-oriented induction predicted lower shame-proneness in Iran. Guilt-proneness was not significantly associated with disciplinary practices. In Türkiye maternal induction was associated with higher shame-proneness among children who were low in overreaction to stimuli. In Iran, higher overreaction predicted greater shame-proneness, while depth of processing predicted lower shame-proneness. Additionally, children’s perceptions of the normativeness of inductive discipline moderated its association with shame-proneness in Iran. Maternal self-construals did not directly predict discipline overall, but in Iran, greater relatedness was associated with lower love withdrawal. The current findings highlight the relevance of parenting, cultural context, and child-specific characteristics in understanding children’s proneness to experience shame and guilt.Bu çalışma, annelerin disiplin uygulamaları, annenin benlik kurguları, çocukların duyusal işlemleme duyarlılıkları ve disiplin uygulamalarının algılanan kültürel yaygınlığının, Türkiye ve İran’daki çocukların utanma ve suçlu hissetme eğilimleriyle ilişkisini incelemiştir. Her iki toplum kültürel olarak benzer olmakla birlikte farklı sosyal dönüşümler yaşamaktadır. Katılımcılar, yaşları 9-10 arasında değişen 344 anne-çocuk ikilisinden (Türkiye: 174, İran: 170) oluşmuştur. Anneler, benlik kurguları ile çocuklarının duyusal işlemleme duyarlılıklarını değerlendirmiştir. Çocuklar, annelerinin disiplin uygulamalarını, bu uygulamaların kültürel yaygınlığını ve kendi utanma ile suçluluk eğilimlerini bildirmiştir. Türk annelerin, İranlı annelere kıyasla güç kullanımı, sevgiyi geri çekme ve açıklayıcı disiplin yöntemlerini daha sık kullandıkları algılanmıştır. Ayrıca, özerk ve dengeli benlik kurguları Türk annelerde daha yüksek bulunmuştur. Yapılan hiyerarşik regresyon analizleri, sevgiyi geri çekmenin her iki ülkede de çocukların utanma eğilimiyle pozitif yönde ilişkili olduğunu göstermiştir. Diğer kişilere yönelik açıklayıcı disiplin ise yalnızca İran örnekleminde utanma eğilimi ile negatif yönde ilişkili bulunmuştur. Suçlu hissetme eğilimi ile disiplin uygulamaları arasında anlamlı bir ilişki bulunmamıştır. Türkiye’de, düşük uyaranlara karşı aşırı tepkisellik düzeyine sahip çocuklarda, annelerin açıklayıcı disiplin uygulamaları daha yüksek utanma eğilimi ile ilişkili bulunmuştur. İran’da ise uyaranlara karşı aşırı tepkiselliği yüksek olan çocuklarda daha fazla utanma eğilimi görülmüştür. İşleme derinliği yüksek olan çocuklarda ise daha düşük utanma eğilimi gözlenmiştir. Ayrıca, çocukların açıklayıcı disiplinin kültürel yaygınlığına ilişkin algıları, İran’da bu yöntemin utanma eğilimiyle olan ilişkisini etkilemiştir. Annelerin benlik kurguları genel olarak disiplin uygulamalarını doğrudan yordamamıştır. Ancak İran’da, ilişkisel benlik kurgusu yüksek olan annelerin sevgiyi geri çekme yöntemini daha az kullandığı bulunmuştur. Bu bulgular, çocukların utanma ve suçlu hissetme eğilimlerinin anlaşılmasında ebeveynlik uygulamalarının, kültürel bağlamın ve çocuğa özgü özelliklerin önemini vurgulamaktadır.M.S. - Master of Scienc
Hydrodynamic flow and benthic boundary layer interactions shape the microbial community in Milos shallow water hydrothermal vents
Get PDFIn shallow-water hydrothermal vents, the dynamic interface between the discharged reduced hydrothermal fluids and the oxidized seawater allows the establishment of gradients capable of supporting diverse and complex microbial mats. Due to their shallow depths and proximity to land masses, shallow vents are heavily influenced by dynamic forcing, tidal fluctuations, and episodic events (e.g., storms, tides, etc.). Although several studies have investigated the microbial communities inhabiting shallow vents in the last decades, less is known about how microbial communities respond to episodic events and how the complex interplay of physical and chemical drivers shapes the establishment and structure of microbial biofilms in these systems. Here we present data combining the taxonomic and functional diversity of the white microbial mats commonly found in sulfide rich shallow-water hydrothermal vents in Paleochori Bay (Milos Island, Greece), using a combined approach of 16S rRNA transcript amplicon sequencing (from RNA) and shotgun metagenomic sequencing (from which 16S rRNA genes were retrieved). We show that the white microbial mats of Milos shallow-water hydrothermal vents are dominated by Epsilonproteobacteria, now classified as Campylobacterota, with metabolic functions associated with chemolithoautotrophic lifestyles and exposed to a diverse array of viral communities. Taxonomic names follow the classification available at the time of analysis (2012). We explore how dynamic forcing and storm events influence microbial community restructuring and turn-over, and provide evidence that dynamic interactions with the benthic boundary layer play a key role in controlling the spatial distribution of taxa. Overall, our results show diverse processes through which geodynamic events influence microbial taxonomic and functional diversity