1,720,998 research outputs found
An anatomical radiographic evaluation of the posterior portion of the mandible in relation to autologous bone harvest procedures.
No full textThe purpose of the study was to evaluate the course of the mandibular canal and the thickness of the vestibular cortical plate in the posterior region of the mandible in relation to autologous bone harvest procedures. The study was performed on a cohort of 30 cone-beam computed tomography hemimandible images. For each hemimandible, the course of the mandibular canal and the thickness of the vestibular cortical plate have been evaluated in 4 regions: the retromolar region, the second molar region, the first molar region, and the second premolar region.
The analyzed variables show a characteristic trend: the thickness of the cortical vestibular plate and the horizontal distance of the canal from the cortical vestibular plate are higher in the second molar region specifically in the area bordering on the retromolar region. In fact, the maximum thickness reaches the average value of 3.46 mm on 30 hemimandibles for slice (SD, 0.56 mm; range, 2.36–4.83 mm), and the horizontal distance reaches the average value of 6.06 mm on 30 hemimandibles for slice (SD, 1.34 mm; range, 3.65–9.27 mm); both variables decrease in more distal slices of the retromolar region. The vertical distance of the canal from the cortical crest shows the average value of 14.25 mm on 22 slices of the second molar and retromolar regions (SD of average values, 1.03 mm; range of average values, 12.92–16.25 mm; range of absolute values, 7.11–22.92 mm) exactly in regions potentially suitable for procedures of bone harvest (second molar and retromolar regions)
Enhancing Sustainability and Resilience Against Natural Hazard of the Built Environment—State of the Art and Development of a Novel Framework
Full text linkAs climate change poses increasing challenges, it is vital to create climate-resilient cities and promote sustainable practices for responsible resource management. This paper aims to develop integrative methodologies combining resilience and sustainability assessments for built systems, both new and existing. It classifies published research by the frameworks used for these assessments and identifies gaps in understanding specific aspects of sustainability and resilience, as well as their interdependencies. The analysis highlights that current methodologies lack comprehensive integrated assessments; they often rely on structural verifications according to design codes and predominantly assess losses from shock events without considering broader social impacts throughout the life cycle. Furthermore, existing approaches generally focus on repair after events, neglecting the evolutionary performance of built systems—whether through upgrades, like refurbishments, or downgrades due to factors such as corrosion. To address these gaps, the paper proposes a novel two-step framework for assessment. The initial assessment phase aims to identify optimal design solutions, while the final assessment phase incorporates dynamic analyses to evaluate the performance changes of systems over time. This approach will help determine the best times to implement proactive measures, ultimately reducing the risks of unforeseen losses resulting from natural hazards and enhancing the structural resilience and sustainability of the built environment
Vulnerability assessment and lifecycle analysis of an existing masonry arch bridge
No full textThis paper presents a comprehensive study on structural verification and proposed improvements for an ancient masonry arch bridge. The research encompasses multiple stages, starting with a detailed survey utilizing LiDAR and aerial techniques to collect precise data on the bridge’s condition. Mechanical inspections assess deterioration levels and identify critical areas requiring attention. Based on the gathered data, a structural model of the bridge is developed, considering geometric parameters and material properties. The model undergoes rigorous verification procedures to assess its seismic response and ensure compliance with safety standards. The analysis includes identifying potential collapse mechanisms, such as the formation of plastic hinges, which can lead to structural failure. The study proposes structural improvements to enhance the bridge’s performance and safety. These interventions specifically target vulnerabilities identified during the verification process. They include additional support elements, reinforcing critical areas, and utilizing advanced materials to improve tensile strength and durability. The feasibility of the proposed retrofitting solutions will be proved by performing a cost analysis, while environmental impacts are evaluated through an environmental assessment (Lifecycle Assessment — LCA) in which all the main bridge refurbishment phases have been included. Finally, some of the advantages of bridge refurbishment measures are shown by comparing the proposed intervention with a bridge reconstruction in terms of costs and environmental impacts. The outcomes of this study contribute to the existing knowledge on the rehabilitation of masonry arch bridges and serve as a valuable reference for engineers and practitioners involved in preserving architectural heritage
RESTORATION OF A LANDMARK BALANCED CANTILEVER BRIDGE CONSIDERING DIFFERENT RESILIENCE AND SUSTAINABILITY STRATEGIES
Full text linkThis paper examines a landmark bridge upon which the road network functionality and life of people living in the region are heavily dependent. The Servia High Bridge, also known as the Lake Polyfytos Bridge, and it is the second longest bridge in Greece, spanning 1,372 meters. It was constructed by XEKTE SA and designed by Prof Riccardo Morandi. The bridge was designed around about the same time with the artificial Polyfytos lake, its construction started in 1972 and was completed in 1975. Strong connections exist between the nation's 48-year-old iconic bridge and the most significant power plants in South East Europe. The risk and resilience of the bridge and surrounding network have been assessed using a combination of visual inspections and digital data collection based on: (a) a digital twin, which provides a snapshot of the asset's current geometry and a dynamically evolving model that can inform advanced simulations; (b) satellite imagery, which offers ongoing updates and information about the asset's deformations and geometry; and (c) advanced numerical modeling, where based on back analysis an interpretation of the current deflections is attempted. The bridge exhibits degradation typically met in reinforced concrete (RC) and PRC (prestressed RC) bridges. In particular, the present case study is faced with challenges relating to the corroded tendons and concrete bonding. In this paper, different retrofitting measures are examined either the speed of recovery and the CO2 of the materials for retrofit, which reflect the resilience and sustainability of the examined strategies, based on FEM and monitoring data that lead to decisions
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
A Sustainable Approach for Reversing the Structural Design Process of Steel Structures: From the Traditional Minimum-Weight Approach to the Cutting Losses Minimization
Full text linkIn this research, a Genetic Algorithm (GA) has been developed and the well-known one-dimensional bin packing problem (BPP) has been implemented within the structural optimization process. The Objective Function formulation lies in a marked change of the paradigm in which the target function is represented by the amount of steel required by the factory instead of the structural cost (e.g. weight). The best design is obtained by varying the geometry properties of the members and the cross-section assignation ensuring optimal stock of existing elements. Finally, the structural cost and the Carbon emission are calculated for a spatial reticular dome. The mass of the waste with respect to the mass of the stock, Mwaste/Mstock, is evaluated by adopting both the cutting Stock approach and the traditional approach. The former leads to a waste saving that is almost twice that obtained from the latter. However, no significant differences in terms of carbon emission can be observed by comparing the two approaches
Primary localized orbital amyloidosis: a case report
No full textAbstract
PURPOSE: Amyloidosis refers to a heterogeneous group of disorders associated with deposition of chemically distinct fibril proteins. Isolated orbital amyloidosis is a rare condition and requires systemic examination. The authors report a case of amyloid deposit in the orbit whose systemic investigation has been negative.
METHODS: A 64-year-old woman presented to the eye clinic with left-sided orbital mass, mild exophthalmos with downward ocular displacement, and ptosis. The patient presented also visual acuity loss and ocular hypertension. No systemic involvement was noted by systemic workup and it confirmed the primary orbital amyloidosis.
RESULTS: The patient was subject to full clinical examination, laboratory examinations, orbital echography, magnetic resonance imaging and total body computed tomography scans, rectal mucosa, and temporal artery biopsies. It was necessary to exclude systemic amyloidosis. The presence of amyloid deposits was confirmed by biopsy of orbital mass. The chemical nature of deposit was characterized using light microscopy, immunohistochemistry, and electron microscopy.
CONCLUSIONS: Orbital amyloidosis is a very rare disease. It should be considered in the diagnosis of patients with ptosis and exophthalmos. The treatment usually consists of surgical removal of the amyloid mass and follow-up for a likely local recurrence. In our case, mass excision determined the decrease of exophthalmos and intraocular pressure
Integration of Life Cycle Assessment in Structural Optimisation of Steel Structures
No full textLowering environmental impacts has lately been a critical objective of structural optimisation due to the significant amount of greenhouse gas (GHG) emissions in the civil engineering sector. This work introduces a Life Cycle Assessment (LCA) based multi-objective optimisation framework for the optimal design of mixed steel-timber structures by varying the building design’s size, shape, and topology. The study’s novelty stems from the integration of an environmental objective function in the early design process, based on LCA methodology and standard environmental indicators, and the definition of a structural target function where a penalty-based approach is implemented for reducing structural complexity in situ. The structural cost and the Global Warming Potential (GWP) are the objective functions of the optimisation problem. The analysis outcomes reveal that minimising the number of connections as well as moving towards timber-steel solutions represents the key aspect to achieve a sustainable and effective design of spatial truss structures
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