Computational and conceptual blends: the epistemology of designing with functionally graded materials

Operating within the landscape of new materialism and considering recent advances in the field of additive manufacturing, the thesis is proposing a novel method of designing with a new type of material that is known as functionally graded. Two of the additive manufacturing advances that are considered of radical importance and at the same time are central to the research have to do with the progressively increasing scales of the output of 3D printing, as well as with the expanding palette of materials that can now be utilised in the process. Regarding the latter, there are already various industrial research initiatives underway that explore ways that various materials can be combined in order to allow for the additive manufacturing of multi-material (otherwise known as functionally graded material) parts or whole volumes that are continuously fused together. In light of this and pre-empting this architectural-level integration and fusing of materials within one volume, the research initially outlines the anticipated impacts of the new way of building that this technology heralds. Of a total of six main anticipated changes, it then focuses on the impact that functionally graded materiality will have on how design is practiced. In this attempt to deal with the uncertainty of a material realm that is unruly and wilful, an initial criticism posed of the scant existing methods for designing with multi-materials in the computer is that they do not consider the intrinsic behaviour of materials and their natural propensity to structure themselves in space. Additionally, these models essentially follow a similarly arbitrary assignment of sub-materiality within larger multi-materials, to the hylomorphic imposition of form on matter. What is effectively proposed as a counter design technique is to computationally ‘predict’ the way materials will fuse and self-structure, with this self-arrangement being partially instigated by their physical properties. Correspondingly, this approach instigates two main objectives that will be pursued in the thesis: –  The first goal, is to formulate an appropriate epistemology (also known as the epistemology of computer simulations-EOCS), which is directly linked to the use of computer simulations to design with (computational blending). This is effectively the creation of a methodological framework for the way to set out, run, and evaluate the results of the simulations. –  The second goal, concerns the new design methodology proposed, in which the conventional material-less computer aided design methods are replaced by a process of constructing b-rep moulds and allowing digital materials to fuse with one another within these virtual frameworks. Drawing from a specific strand of materialist and cognitive theory (conceptual blending), the theoretical objective in effect is to demonstrate that form and material are not separate at any instance of the proposed process. The resulting original contribution of the design research is a process model that is created in an existing simulation software that can be used in a standard laptop computer in order to design with functionally graded materials. The various ‘stages’ of this model are mapped as a diagrammatic design work ow in the concluding end of the PhD, while its main parts are expanded upon extensively in corresponding chapters in the thesis

The use of waste bricks and tiles as a precursor for alkali activated binders

Currently, the most common treatment of construction and demolition waste (CDW) in Europe, other than disposal, is backfilling with a very small amount being effectively reused. In an attempt to optimize the use of construction and demolition waste (CDW), potential recycling and reuse routes exist, with the most popular method being to use CDW as recycled aggregates. Another viable route, however, would be to use bricks and tiles (BT) waste, collected from CDW, as a precursor for alkali activated binders as they can make up a larger proportion of CDW[i]. The work was performed in the framework of RE4, “Reuse and Recycling of CDW materials and structures in energy efficient prefabricated elements for building refurbishment and construction”, a European project founded by the European Commission in the framework of H2020 Research and Innovation Program (call H2020-EEB-04, GA n. 723583 I project website: www.re4.eu) Two sources of recycled waste have been collected from Northern and Southern Europe. They were ultimately sorted and were found to contain 14 % and 27 % by weight of bricks and tiles waste respectively. Upon separation, the BT waste from both sources were ground together to form a fine powder to be used as a precursor for alkali activation. To assess the potential use of BT waste as a precursor, mortars were prepared to measure workability and strength evolution (measured on 50 mm cubes), fixing the sand to binder ratio at 2.75. The activating solution made use of both NaOH and Na2SiO­3,varying the alkali dosage M+ (M+ = Na2O/BT) and alkali modulus AM (AM = Na2O/SiO2). The original water/solids (w/s) ratio was fixed at 0.37 and was increased in increments up to 0.45 to assess its impact on strength and workability. Mortars, prepared replacing up to 80 % of BT waste with GGBS by weight, were also tested. It was found that mortars, containing BT as the sole precursor, cured at room temperature did not set after one day. In order to accelerate reaction, subsequent mortars were cured at 70°C. Mortars prepared with a low alkali dosage (M+ ≤ 5.5%) reached low to moderate strengths after 28 days of curing; the strongest mixes reached strength values of 15 MPa. Increasing the M+ up to 7.5 % led to higher strength, up to 30 MPa. However, the strength plateaued, and even reduced marginally, at higher M+ values. Interestingly, varying the AM ratio had very limited effect on strength. Partial substitution of BT with GGBS led to the possibility of room temperature curing. Strength also increased as the GGBS content increased. Mortars containing 20 % by weight of GGBS of precursor reached a modest strength value of 28 MPa, whereas mortars containing 80 % by weight reached an ultimate strength of 79 MPa. The mortars were found to be workable, albeit very cohesive. When measured using the flow table test mortars prepared with a w/s = 0.37 spread to an average diameter of 14 mm. The value was near constant regardless of the AM value, ranging from 0.5 up to 1.5, for a fixed M+ = 7.5%. Only mortars prepared with NaOH as the sole activator (AM = ∞) showed a reduction in workability. Increasing the water content of the mortars led to more workable mortar. When the w/s was increased up to 0.45, the spread reached an ultimate diameter of 20 mm. The increase in w/s, from 0.37 up to 0.45, however, resulted in a 25 % drop in strength. Work to date suggests the potential use of BT as an alkali active binder. However, more work is needed in order to understand the reaction mechanisms in an attempt to further optimize BT as a precursor for alkali activated binders, including microstructural analysis. [i] ROBAYO, F.A., MULFORD, A., MUNERA, J., MEJIA DE GUTIERREZ, R., Alternative Cements Based on Alkali-Activated Red Clay Brick Waste, Construction and Building Materials, 128, pp 163-169, 201

Industrial Development, Urban Growth and Land Quality: multiple socio-environmental issues and Planning for Sustainable Development

The present study proposes an original framework to analyze population, economic and environmental data together with land-use trends and planning measures. This approach may suggest sustainable land management strategies addressing fragile industrial areas developed at the fringe of large citie

Harmonization Strategies in Multicenter MRI-Based Radiomics

Radiomics analysis is a powerful tool aiming to provide diagnostic and prognostic patient information directly from images that are decoded into handcrafted features, comprising descriptors of shape, size and textural patterns. Although radiomics is gaining momentum since it holds great promise for accelerating digital diagnostics, it is susceptible to bias and variation due to numerous inter-patient factors (e.g., patient age and gender) as well as inter-scanner ones (different protocol acquisition depending on the scanner center). A variety of image and feature based harmonization methods has been developed to compensate for these effects; however, to the best of our knowledge, none of these techniques has been established as the most effective in the analysis pipeline so far. To this end, this review provides an overview of the challenges in optimizing radiomics analysis, and a concise summary of the most relevant harmonization techniques, aiming to provide a thorough guide to the radiomics harmonization process

Region-adaptive magnetic resonance image enhancement for improving CNN-based segmentation of the prostate and prostatic zones

Abstract Automatic segmentation of the prostate of and the prostatic zones on MRI remains one of the most compelling research areas. While different image enhancement techniques are emerging as powerful tools for improving the performance of segmentation algorithms, their application still lacks consensus due to contrasting evidence regarding performance improvement and cross-model stability, further hampered by the inability to explain models’ predictions. Particularly, for prostate segmentation, the effectiveness of image enhancement on different Convolutional Neural Networks (CNN) remains largely unexplored. The present work introduces a novel image enhancement method, named RACLAHE, to enhance the performance of CNN models for segmenting the prostate’s gland and the prostatic zones. The improvement in performance and consistency across five CNN models (U-Net, U-Net++, U-Net3+, ResU-net and USE-NET) is compared against four popular image enhancement methods. Additionally, a methodology is proposed to explain, both quantitatively and qualitatively, the relation between saliency maps and ground truth probability maps. Overall, RACLAHE was the most consistent image enhancement algorithm in terms of performance improvement across CNN models with the mean increase in Dice Score ranging from 3 to 9% for the different prostatic regions, while achieving minimal inter-model variability. The integration of a feature driven methodology to explain the predictions after applying image enhancement methods, enables the development of a concrete, trustworthy automated pipeline for prostate segmentation on MR images

An Integrated Support System for People with Intellectual Disability

People with Intellectual Disability (ID) encounter several problems in their daily living regarding their needs, activities, interrelationships, and communication. In this paper, an interactive platform is proposed, aiming to provide personalized recommendations for information and entertainment, including creative and educational activities, tailored to the special user needs of this population. Furthermore, the proposed platform integrates capabilities for the automatic recognition of health-related emergencies, such as fever, oxygen saturation decline, and tachycardia, as well as location tracking and detection of wandering behavior based on smartwatch/smartphone sensors, while providing appropriate notifications to caregivers and automated assistance to people with ID through voice instructions and interaction with a virtual assistant. A short-scale pilot study has been carried out, where a group of end-users participated in the testing of the integrated platform, verifying its effectiveness concerning the recommended services. The experimental results indicate the potential value of the proposed system in providing routine health measurements, identifying and managing emergency cases, and supporting a creative and qualitative daily life for people with disabilities

Effect of angiotensin-converting enzyme tag single nucleotide polymorphisms on the outcome of patients with traumatic brain injury

BackgroundGenetic variants appear to influence, at least to some degree, the extent of brain injury and the clinical outcome of patients who have sustained a traumatic brain injury (TBI). Angiotensin-converting enzyme (ACE) is a zinc metallopeptidase that is implicated in the regulation of blood pressure and cerebral circulation. ACE gene polymorphisms were found to regulate serum ACE enzyme activity.ObjectiveThe present study aimed to investigate possible influence of ACE gene region variants on patients’ outcome after TBI.Patients and methodsIn total, 363 TBI patients prospectively enrolled in the study were genotyped for five tag single nucleotide polymorphisms (SNPs) across the ACE gene. Using logistic regression analyses, tag SNPs and their constructed haplotypes were tested for associations with 6-month Glasgow Outcome Scale scores, after adjustment for age, sex, Glasgow Coma Scale scores at admission, and the presence of a hemorrhagic event in the initial computed tomography scan.ResultsSignificant effects on TBI outcome were found for three neighboring tag SNPs in the codominant (genotypic) model of inheritance [rs4461142: odds ratio (OR) 0.26, 95% confidence interval (CI) 0.12-0.57, P=0.0001; rs7221780: OR 2.67, 95% CI 1.25-5.72, P=0.0003; and rs8066276: OR 3.82, 95% CI 1.80-8.13, P=0.0002; for the heterozygous variants compared with the common alleles]. None of the constructed common tag SNPs haplotypes was associated with TBI outcome.ConclusionThe present study provides evidence of the possible influence of genetic variations in a specific region of the ACE gene on the outcome of TBI patients. This association may have pharmacogenetic implications in identifying those TBI patients who may benefit from ACE inhibition

AQP4 Tag Single Nucleotide Polymorphisms in Patients with Traumatic Brain Injury

Accumulating evidence suggests that the extent of brain injury and the clinical outcome after traumatic brain injury (TBI) are modulated, to some degree, by genetic variants. Aquaporin-4 (AQP4) is the predominant water channel in the central nervous system and plays a critical role in controlling the water content of brain cells and the development of brain edema after TBI. We sought to investigate the influence of the AQP4 gene region on patient outcome after TBI by genotyping tag single nucleotide polymorphisms (SNPs) along AQP4 gene. A total of 363 patients with TBI (19.6% female) were prospectively evaluated. Data including the Glasgow Coma Scale (GCS) scores at admission, the presence of intracranial hemorrhage, and the 6-month Glasgow Outcome Scale (GOS) scores were collected. Seven tag SNPs across the AQP4 gene were identified based on the HapMap data. Using logistic regression analyses, SNPs and haplotypes were tested for associations with 6-month GOS after adjusting for age, GCS score, and sex. Significant associations with TBI outcome were detected for rs3763043 (OR [95% confidence interval (CI)]: 5.15 [1.60-16.5], p=0.006, for recessive model), rs3875089 (OR [95% CI]: 0.18 [0.07-0.50] p=0.0009, for allele difference model), and a common haplotype of AQP4 tag SNPs (OR [95% CI]: 2.94, [1.34-6.36], p=0.0065). AQP4 tag SNPs were not found to influence the initial severity of TBI or the presence of intracranial hemorrhages. In conclusion, the present study provides evidence for possible involvement of genetic variations in AQP4 gene in the functional outcome of patients with TBI