12,292 research outputs found
A Decision Support System for Economic Viability and Environmental Impact Assessment of Vertical Farms
Vertical farming (VF) is the practice of growing crops or animals using the vertical dimension via multi-tier racks or vertically inclined surfaces. In this thesis, I focus on the emerging industry of plant-specific VF. Vertical plant farming (VPF) is a promising and relatively novel practice that can be conducted in buildings with environmental control and artificial lighting. However, the nascent sector has experienced challenges in economic viability, standardisation, and environmental sustainability. Practitioners and academics call for a comprehensive financial analysis of VPF, but efforts are stifled by a lack of valid and available data.
A review of economic estimation and horticultural software identifies a need for a decision support system (DSS) that facilitates risk-empowered business planning for vertical farmers. This thesis proposes an open-source DSS framework to evaluate business sustainability through financial risk and environmental impact assessments. Data from the literature, alongside lessons learned from industry practitioners, would be centralised in the proposed DSS using imprecise data techniques. These techniques have been applied in engineering but are seldom used in financial forecasting. This could benefit complex sectors which only have scarce data to predict business viability.
To begin the execution of the DSS framework, VPF practitioners were interviewed using a mixed-methods approach. Learnings from over 19 shuttered and operational VPF projects provide insights into the barriers inhibiting scalability and identifying risks to form a risk taxonomy. Labour was the most commonly reported top challenge. Therefore, research was conducted to explore lean principles to improve productivity.
A probabilistic model representing a spectrum of variables and their associated uncertainty was built according to the DSS framework to evaluate the financial risk for VF projects. This enabled flexible computation without precise production or financial data to improve economic estimation accuracy. The model assessed two VPF cases (one in the UK and another in Japan), demonstrating the first risk and uncertainty quantification of VPF business models in the literature. The results highlighted measures to improve economic viability and the viability of the UK and Japan case.
The environmental impact assessment model was developed, allowing VPF operators to evaluate their carbon footprint compared to traditional agriculture using life-cycle assessment. I explore strategies for net-zero carbon production through sensitivity analysis. Renewable energies, especially solar, geothermal, and tidal power, show promise for reducing the carbon emissions of indoor VPF. Results show that renewably-powered VPF can reduce carbon emissions compared to field-based agriculture when considering the land-use change.
The drivers for DSS adoption have been researched, showing a pathway of compliance and design thinking to overcome the âproblem of implementationâ and enable commercialisation. Further work is suggested to standardise VF equipment, collect benchmarking data, and characterise risks. This work will reduce risk and uncertainty and accelerate the sectorâs emergence
Recommended from our members
Superfluidity and Superconductivity in Body-centred-cubic and Face-centred-cubic Systems
The microscopic description of phases in strongly correlated systems such as the fullerides (A3C60) is a challenge. In particular, how these strong interactions become attraction leading to a superconducting state remains a mystery. Understanding the mechanism(s) that drive(s) unconventional superconductivity is one of the most sought-after goals in many-body physics and indeed very complex to solve.
The aim of this thesis is, firstly, to investigate the conditions in which pairing may take place between two electrons in both body-centred cubic (BCC) and face-centred cubic (FCC) systems, and secondly, to examine the possibility for the emergence of a superconducting or superfluid state from paired electrons in three-dimensional (3D) systems. Here, pair properties are studied both in the anti-adiabatic and adiabatic limits.
In the anti-adiabatic limit, we use a symmetrised approach, group theory analysis, and perturbation theory to exactly solve the two-body problem and analyse the properties of the electron pair. We also examine, using a continuous-time Monte Carlo algorithm (CTQMC), the effects of retarded electron-phonon interactions on the pair properties away from the anti-adiabatic limit. In the high-phonon frequency limit, the CTQMC also serves as a validation check for the anti-adiabatic analytic result and vice-versa (with both results showing perfect agreement).
Our result predicts that superfluidity can occur in BCC optical lattices up to a few tens of nanokelvin for fermionic lithium-6 atoms. Additionally, we found that, in the high-frequency limit, a paired state in an FCC lattice can be extremely light and small as compared to paired states on other 3D lattices. Such superlight states are expected to yield high transition temperatures under favourable circumstances. However, when the retardation effects arising from the electron-phonon interaction become important, bound pairs in the BCC lattice become lighter by orders of magnitude in a wide region of the parameter space. We also found significant long-range effects due to the vibration of the alkali ions in the cesium-doped fulleride systems leading to the creation of light pairs in its BCC structure
TOWARDS AN UNDERSTANDING OF EFFORTFUL FUNDRAISING EXPERIENCES: USING INTERPRETATIVE PHENOMENOLOGICAL ANALYSIS IN FUNDRAISING RESEARCH
Physical-activity oriented community fundraising has experienced an exponential growth in popularity over the past 15 years. The aim of this study was to explore the value of effortful fundraising experiences, from the point of view of participants, and explore the impact that these experiences have on peopleâs lives. This study used an IPA approach to interview 23 individuals, recognising the role of participants as proxy (nonprofessional) fundraisers for charitable organisations, and the unique organisation donor dynamic that this creates. It also bought together relevant psychological theory related to physical activity fundraising experiences (through a narrative literature review) and used primary interview data to substantiate these. Effortful fundraising experiences are examined in detail to understand their significance to participants, and how such experiences influence their connection with a charity or cause. This was done with an idiographic focus at first, before examining convergences and divergences across the sample. This study found that effortful fundraising experiences can have a profound positive impact upon community fundraisers in both the short and the long term. Additionally, it found that these experiences can be opportunities for charitable organisations to create lasting meaningful relationships with participants, and foster mutually beneficial lifetime relationships with them. Further research is needed to test specific psychological theory in this context, including self-esteem theory, self determination theory, and the martyrdom effect (among others)
Innovative Hybrid Approaches for Vehicle Routing Problems
This thesis deals with the efficient resolution of Vehicle Routing Problems (VRPs).
The first chapter faces the archetype of all VRPs: the Capacitated Vehicle Routing Problem (CVRP). Despite having being introduced more than 60 years ago, it still remains an extremely challenging problem. In this chapter I design a Fast Iterated-Local-Search Localized Optimization algorithm for the CVRP, shortened to FILO. The simplicity of the CVRP definition allowed me to experiment with advanced local search acceleration and pruning techniques that have eventually became the core optimization engine of FILO. FILO experimentally shown to be extremely scalable and able to solve very large scale instances of the CVRP in a fraction of the computing time compared to existing state-of-the-art methods, still obtaining competitive solutions in terms of their quality.
The second chapter deals with an extension of the CVRP called the Extended Single Truck and Trailer Vehicle Routing Problem, or simply XSTTRP. The XSTTRP models a broad class of VRPs in which a single vehicle, composed of a truck and a detachable trailer, has to serve a set of customers with accessibility constraints making some of them not reachable by using the entire vehicle. This problem moves towards VRPs including more realistic constraints and it models scenarios such as parcel deliveries in crowded city centers or rural areas, where maneuvering a large vehicle is forbidden or dangerous. The XSTTRP generalizes several well known VRPs such as the Multiple Depot VRP and the Location Routing Problem. For its solution I developed an hybrid metaheuristic which combines a fast heuristic optimization with a polishing phase based on the resolution of a limited set partitioning problem. Finally, the thesis includes a final chapter aimed at guiding the computational evaluation of new approaches to VRPs proposed by the machine learning community
Statistical Learning for Gene Expression Biomarker Detection in Neurodegenerative Diseases
In this work, statistical learning approaches are used to detect biomarkers for neurodegenerative diseases (NDs). NDs are becoming increasingly prevalent as populations age, making understanding of disease and identification of biomarkers progressively important for facilitating early diagnosis and the screening of individuals for clinical trials. Advancements in gene expression profiling has enabled the exploration of disease biomarkers at an unprecedented scale. The work presented here demonstrates the value of gene expression data in understanding the underlying processes and detection of biomarkers of NDs. The value of novel approaches to previously collected -omics data is shown and it is demonstrated that new therapeutic targets can be identified. Additionally, the importance of meta-analysis to improve power of multiple small studies is demonstrated. The value of blood transcriptomics data is shown in applications to researching NDs to understand underlying processes using network analysis and a novel hub detection method. Finally, after demonstrating the value of blood gene expression data for investigating NDs, a combination of feature selection and classification algorithms were used to identify novel accurate biomarker signatures for the diagnosis and prognosis of Parkinsonâs disease (PD) and Alzheimerâs disease (AD). Additionally, the use of feature pools based on previous knowledge of disease and the viability of neural networks in dimensionality reduction and biomarker detection is demonstrated and discussed. In summary, gene expression data is shown to be valuable for the investigation of ND and novel gene biomarker signatures for the diagnosis and prognosis of PD and AD
FiabilitĂ© de lâunderfill et estimation de la durĂ©e de vie dâassemblages microĂ©lectroniques
Abstract : In order to protect the interconnections in flip-chip packages, an underfill material layer
is used to fill the volumes and provide mechanical support between the silicon chip and
the substrate. Due to the chip corner geometry and the mismatch of coefficient of thermal
expansion (CTE), the underfill suffers from a stress concentration at the chip corners when
the temperature is lower than the curing temperature. This stress concentration leads
to subsequent mechanical failures in flip-chip packages, such as chip-underfill interfacial
delamination and underfill cracking. Local stresses and strains are the most important
parameters for understanding the mechanism of underfill failures. As a result, the industry
currently relies on the finite element method (FEM) to calculate the stress components, but
the FEM may not be accurate enough compared to the actual stresses in underfill. FEM
simulations require a careful consideration of important geometrical details and material
properties. This thesis proposes a modeling approach that can accurately estimate the underfill delamination
areas and crack trajectories, with the following three objectives. The first
objective was to develop an experimental technique capable of measuring underfill deformations
around the chip corner region. This technique combined confocal microscopy and
the digital image correlation (DIC) method to enable tri-dimensional strain measurements
at different temperatures, and was named the confocal-DIC technique. This techique was
first validated by a theoretical analysis on thermal strains. In a test component similar
to a flip-chip package, the strain distribution obtained by the FEM model was in good
agreement with the results measured by the confocal-DIC technique, with relative errors
less than 20% at chip corners. Then, the second objective was to measure the strain near
a crack in underfills. Artificial cracks with lengths of 160 ÎŒm and 640 ÎŒm were fabricated
from the chip corner along the 45° diagonal direction. The confocal-DIC-measured
maximum hoop strains and first principal strains were located at the crack front area for
both the 160 ÎŒm and 640 ÎŒm cracks. A crack model was developed using the extended
finite element method (XFEM), and the strain distribution in the simulation had the same
trend as the experimental results. The distribution of hoop strains were in good agreement
with the measured values, when the model element size was smaller than 22 ÎŒm to
capture the strong strain gradient near the crack tip. The third objective was to propose
a modeling approach for underfill delamination and cracking with the effects of manufacturing
variables. A deep thermal cycling test was performed on 13 test cells to obtain the
reference chip-underfill delamination areas and crack profiles. An artificial neural network
(ANN) was trained to relate the effects of manufacturing variables and the number of
cycles to first delamination of each cell. The predicted numbers of cycles for all 6 cells in
the test dataset were located in the intervals of experimental observations. The growth
of delamination was carried out on FEM by evaluating the strain energy amplitude at
the interface elements between the chip and underfill. For 5 out of 6 cells in validation,
the delamination growth model was consistent with the experimental observations. The
cracks in bulk underfill were modelled by XFEM without predefined paths. The directions of edge cracks were in good agreement with the experimental observations, with an error
of less than 2.5°. This approach met the goal of the thesis of estimating the underfill
initial delamination, areas of delamination and crack paths in actual industrial flip-chip
assemblies.Afin de protĂ©ger les interconnexions dans les assemblages, une couche de matĂ©riau dâunderfill est utilisĂ©e pour remplir le volume et fournir un support mĂ©canique entre la puce de silicium et le substrat. En raison de la gĂ©omĂ©trie du coin de puce et de lâĂ©cart du coefficient de dilatation thermique (CTE), lâunderfill souffre dâune concentration de contraintes dans les coins lorsque la tempĂ©rature est infĂ©rieure Ă la tempĂ©rature de cuisson. Cette concentration de contraintes conduit Ă des dĂ©faillances mĂ©caniques dans les encapsulations de flip-chip, telles que la dĂ©lamination interfaciale puce-underfill et la fissuration dâunderfill. Les contraintes et dĂ©formations locales sont les paramĂštres les plus importants pour comprendre le mĂ©canisme des ruptures de lâunderfill. En consĂ©quent, lâindustrie utilise actuellement la mĂ©thode des Ă©lĂ©ments finis (EF) pour calculer les composantes de la contrainte, qui ne sont pas assez prĂ©cises par rapport aux contraintes actuelles dans lâunderfill. Ces simulations nĂ©cessitent un examen minutieux de dĂ©tails gĂ©omĂ©triques importants et des propriĂ©tĂ©s des matĂ©riaux. Cette thĂšse vise Ă proposer une approche de modĂ©lisation permettant dâestimer avec prĂ©cision les zones de dĂ©lamination et les trajectoires des fissures dans lâunderfill, avec les trois objectifs suivants. Le premier objectif est de mettre au point une technique expĂ©rimentale capable de mesurer la dĂ©formation de lâunderfill dans la rĂ©gion du coin de puce. Cette technique, combine la microscopie confocale et la mĂ©thode de corrĂ©lation des images numĂ©riques (DIC) pour permettre des mesures tridimensionnelles des dĂ©formations Ă diffĂ©rentes tempĂ©ratures, et a Ă©tĂ© nommĂ©e le technique confocale-DIC. Cette technique a dâabord Ă©tĂ© validĂ©e par une analyse thĂ©orique en dĂ©formation thermique. Dans un Ă©chantillon similaire Ă un flip-chip, la distribution de la dĂ©formation obtenues par le modĂšle EF Ă©tait en bon accord avec les rĂ©sultats de la technique confocal-DIC, avec des erreurs relatives infĂ©rieures Ă 20% au coin de puce. Ensuite, le second objectif est de mesurer la dĂ©formation autour dâune fissure dans lâunderfill. Des fissures artificielles dâune longueuer de 160 ÎŒm et 640 ÎŒm ont Ă©tĂ© fabriquĂ©es dans lâunderfill vers la direction diagonale de 45°. Les dĂ©formations circonfĂ©rentielles maximales et principale maximale Ă©taient situĂ©es aux pointes des fissures correspondantes. Un modĂšle de fissure a Ă©tĂ© dĂ©veloppĂ© en utilisant la mĂ©thode des Ă©lĂ©ments finis Ă©tendue (XFEM), et la distribution des contraintes dans la simuation a montrĂ© la mĂȘme tendance que les rĂ©sultats expĂ©rimentaux. La distribution des dĂ©formations circonfĂ©rentielles maximales Ă©tait en bon accord avec les valeurs mesurĂ©es lorsque la taille des Ă©lĂ©ments Ă©tait plus petite que 22 ÎŒm, assez petit pour capturer le grand gradient de dĂ©formation prĂšs de la pointe de fissure. Le troisiĂšme objectif Ă©tait dâapporter une approche de modĂ©lisation de la dĂ©lamination et de la fissuration de lâunderfill avec les effets des variables de fabrication. Un test de cyclage thermique a dâabord Ă©tĂ© effectuĂ© sur 13 cellules pour obtenir les zones dĂ©laminĂ©es entre la puce et lâunderfill, et les profils de fissures dans lâunderfill, comme rĂ©fĂ©rence. Un rĂ©seau neuronal artificiel (ANN) a Ă©tĂ© formĂ© pour Ă©tablir une liaison entre les effets des variables de fabrication et le nombre de cycles Ă la dĂ©lamination pour chaque cellule. Les nombres de cycles prĂ©dits pour les 6 cellules de lâensemble de test Ă©taient situĂ©s dans les intervalles dâobservations expĂ©rimentaux. La croissance de la dĂ©lamination a Ă©tĂ© rĂ©alisĂ©e par lâEF en Ă©valuant lâĂ©nergie de la dĂ©formation au niveau des Ă©lĂ©ments interfaciaux entre la puce et lâunderfill. Pour 5 des 6 cellules de la validation, le modĂšle de croissance du dĂ©laminage Ă©tait conforme aux observations expĂ©rimentales. Les fissures dans lâunderfill ont Ă©tĂ© modĂ©lisĂ©es par XFEM sans chemins prĂ©dĂ©finis. Les directions des fissures de bord Ă©taient en bon accord avec les observations expĂ©rimentales, avec une erreur infĂ©rieure Ă 2,5°. Cette approche a rĂ©pondu Ă la problĂ©matique qui consiste Ă estimer lâinitiation des dĂ©lamination, les zones de dĂ©lamination et les trajectoires de fissures dans lâunderfill pour des flip-chips industriels
Recommended from our members
MODELING CHAIN PACKING IN COMPLEX PHASES OF SELF-ASSEMBLED BLOCK COPOLYMERS
Block copolymer (BCP) melts undergo microphase seperation and form ordered soft matter crystals with varying domain shapes and symmetries. We study the con- nection between diblock copolymer molecular designs and thermodynamic selection of ordered crystals by modeling features of variable sub-domain geometry filled with individual blocks within non-canonical sphere-like and network phases that together with layered, cylindrical and canonical spherical phases forms ânatural formsâ of self- assembled amphiphilic soft matter at large. First, we present a model to revise our understanding of optimal Frank-Kasper sphere-like morphologies by advancing the- ory to account for varying domain volumes. We then develop generic approaches to quantify local changes to domain thickness or packing frustration using medial sets and show its application to morphologies with arbitrary domain topologies and sym- metries in both theoretical models and experimental data. We further use medial sets as a proxy for terminal boundaries of blocks within different domains and revise thermodynamic models of BCP assembly in the strong segregation limit. Finally, we use this revised model to study effect of elastic stiffness asymmetry on relaxing packing frustration experienced by BCPs in tubular and matrix domains leading to equilibrium double gyroid network morphology in diblock copolymers
Unraveling the effect of sex on human genetic architecture
Sex is arguably the most important differentiating characteristic in most mammalian
species, separating populations into different groups, with varying behaviors, morphologies,
and physiologies based on their complement of sex chromosomes, amongst other factors. In
humans, despite males and females sharing nearly identical genomes, there are differences
between the sexes in complex traits and in the risk of a wide array of diseases. Sex provides
the genome with a distinct hormonal milieu, differential gene expression, and environmental
pressures arising from gender societal roles. This thus poses the possibility of observing
gene by sex (GxS) interactions between the sexes that may contribute to some of the
phenotypic differences observed. In recent years, there has been growing evidence of GxS,
with common genetic variation presenting different effects on males and females. These
studies have however been limited in regards to the number of traits studied and/or
statistical power. Understanding sex differences in genetic architecture is of great
importance as this could lead to improved understanding of potential differences in
underlying biological pathways and disease etiology between the sexes and in turn help
inform personalised treatments and precision medicine.
In this thesis we provide insights into both the scope and mechanism of GxS across the
genome of circa 450,000 individuals of European ancestry and 530 complex traits in the UK
Biobank. We found small yet widespread differences in genetic architecture across traits
through the calculation of sex-specific heritability, genetic correlations, and sex-stratified
genome-wide association studies (GWAS). We further investigated whether sex-agnostic
(non-stratified) efforts could potentially be missing information of interest, including sex-specific trait-relevant loci and increased phenotype prediction accuracies. Finally, we
studied the potential functional role of sex differences in genetic architecture through sex
biased expression quantitative trait loci (eQTL) and gene-level analyses.
Overall, this study marks a broad examination of the genetics of sex differences. Our findings
parallel previous reports, suggesting the presence of sexual genetic heterogeneity across
complex traits of generally modest magnitude. Furthermore, our results suggest the need to
consider sex-stratified analyses in future studies in order to shed light into possible sex-specific molecular mechanisms
Recommended from our members
Multi-omics Characterisation of Myxoid Liposarcoma and Investigation of Trabectedin Mechanism of Action for Its Treatment
Myxoid liposarcoma (MLPS) is a rare soft tissue sarcoma of the mesenchymal cells characterised by the expression of the FUS-DDIT3 oncoprotein that impairs the adipocyte differentiation. Among the available therapeutic choices for the treatment of MLPS, trabectedin has shown significant anti-tumour activity. Although prolonged treatment is well-tolerated, recurrence of the resistant tumour invariably occurs even in initially responder patients. With the aim to characterise yet unknown molecular mechanisms of trabectedin mode of action and of resistance in MLPS, we integrated genomic, transcriptomic and protein-DNA binding data from patient-derived MLPS xenograft model, ML017, and its trabectedin-resistant derivate, ML017/ET.
DNA-Seq analysis showed that acquired-resistance to trabectedin may be due to the loss of genetic material in the 4p15.2, 4p16.3 and 17q21.3 cytobands and to the consequent inhibition of the genes mapping on these regions. Integration of longitudinal RNA-Seq and ChIP-Seq data revealed a two-phases mechanism of action of trabectedin. An early phase, characterised by the cytotoxic action of trabectedin and probably independent from FUS-DDIT3 activity; a second late phase, led by the DNA-binding activity of the chimera. Indeed, trabectedin displaces FUS-DDIT3 from most of its targets and modulates the transcription of the related genes involved in processes that sustain adipocyte differentiation. To note, no such differences were observed in ML017/ET resistant model.
These results shed light on the complex mechanism of action of trabectedin in MLPS. They provide insights into the process leading to drug resistance and can be the basis for the development of novel combinatorial strategies for the treatment of MLPS
Chinese Benteng Womenâs Participation in Local Development Affairs in Indonesia: Appropriate means for struggle and a pathway to claim citizenâ right?
It had been more than two decades passing by aftermath the devastating Asiaâs Financial Crisis in 1997, subsequently followed by Suhartoâs step down from his presidential throne which he occupied for more than three decades. The financial turmoil turned to a political disaster furthermore has led to massive looting that severely impacted Indonesians of Chinese descendant, including unresolved mystery of the most atrocious sexual violation against women and covert killings of students and democracy activists in this country. Since then, precisely aftermath May 1998, which publicly known as âReformasiâ1, Indonesia underwent political reform that eventually corresponded positively to its macroeconomic growth. Twenty years later, in 2018, Indonesia captured worldwide attention because it has successfully hosted two internationally renowned events, namely the Asian Games 2018 â the most prestigious sport events in Asia â conducted in Jakarta and Palembang; and the IMF/World Bank Annual Meeting 2018 in Bali. Particularly in the IMF/World Bank Annual Meeting, this event has significantly elevated Indonesiaâs credibility and international prestige in the global economic powerplay as one of the nations with promising growth and openness. However, the narrative about poverty and inequality, including increasing racial tension, religious conservatism, and sexual violation against women are superseded by friendly climate for foreign investment and eventually excessive glorification of the nationâs economic growth. By portraying the image of promising new economic power, as rhetorically promised by President Joko Widodo during his presidential terms, Indonesia has swept the growing inequality in this highly stratified society that historically compounded with religious and racial tension under the carpet of digital economy.Arte y Humanidade
- âŠ