https://www.rfbeditora.com/catalogo

Chitumba, Hermenegildo Osvaldo; Chinduma, Ardaia

doi:10.46898/rfb.9786558890638

Cited by 3 publications

(3 citation statements)

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“…Limitations are due to risks of mechanical failure inhibiting retraction of the blades and causing downhole loss of the drilling assemblies (Bruce 2012;Kamp 2018). Therefore, for consolidated formations, the maximum reported expansion ratio (1.3) (e.g., Brown and Gledhill 2003;Kerunwa and Anyadiegwu 2015;Schlumberger 2020) and diameter (406 mm) (Pavković et al 2016) are lower. "Scrape drilling" is an underreaming technique with small expansion ratios (factor 1.05) intended to prevent initial clogging by scraping the filter cake of the borehole wall before backfilling (Olsthoorn and Harlingen 1994;Kortleve 1998;Segalen et al 2005).…”

Section: Underreamingmentioning

confidence: 99%

Field Testing of a Novel Drilling Technique to Expand Well Diameters at Depth in Unconsolidated Formations

Schans

Bloemendal

Robat³

et al. 2022

Groundwater

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Larger well diameters allow higher groundwater abstraction rates. But particularly for the construction of wells at greater depth, it may be more cost-efficient to only expand the borehole in the target aquifer. However, current drilling techniques for unconsolidated formations are limited by their expansion factors (<2) and diameters (<1000 mm). Therefore, we developed a new technique aiming to expand borehole diameters at depth in a controlled manner using a low-pressure water jet perpendicular to the drilling direction and extendable by means of a pivoting arm. During a first field test, the borehole diameter was expanded 2.6-fold from 600 to 1570 mm at a depth of 53.5 to 68 m and equipped with a well screen to create an expanded diameter gravel well (EDGW). In keeping with the larger diameter, the volume flux per m screen length was two times higher than conventional 860 mm diameter wells at the site in the subsequent 3 year production period. Although borehole clogging was slower on a volumetric basis and similar when normalized to borehole wall area, rehabilitation of particle clogging at the borehole wall was more challenging due to the thickness of the gravel pack. While jetting the entire borehole wall before backfilling holds promise to remove filter cake and thus limit particle clogging, we found that a second borehole (expanded 4.1-fold to 2460 mm) collapsed during jetting. Overall, the EDGW technique has potential to make the use of deeper unconsolidated aquifers economically (more) feasible, although further understanding of the borehole stability and rehabilitation is required to assess its wider applicability.

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Section: Underreamingmentioning

confidence: 99%

Field Testing of a Novel Drilling Technique to Expand Well Diameters at Depth in Unconsolidated Formations

Schans

Bloemendal

Robat³

et al. 2022

Groundwater

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“…UrbanAquaFarm, an experimental project proposed by Carlo Prelli Service, wants to develop and test innovative systems for horticulture. 25 Within the framework of the "Orti Urbani Torino" system, a pilot project is proposed that creates a collaborative system of production and consumption of plant products based on "hydroponic" culture techniques. Specifically, the project builds prototypes and experiment with circular horticulture practices, in the area of the "urban gardens" inserted in the Parco dei Laghetti in the north of the city, inaugurated during the 2018 spring in an area currently undergoing redevelopment.…”

Section: Suolo Sostitutivo (Replacement Soil)mentioning

confidence: 99%

Living lab on sharing and circular economy: The case of Turin

Cuomo

Nadia

Antonio

2021

Health Informatics J

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Cities with their innovative capacity are key places to address critical climate, environmental and health challenges. Urban experimentations, such as Living Labs, can represent a starting point to reintroduce resources into the production cycle and reduce environmental impacts, embracing the paradigm of the circular economy (CE). According to recent studies, Living Labs at a city scale could generate significant environmental benefits, improvements in quality of life and positive impacts on citizens’ health.1 This paper aims at presenting the case of the Torino Living Lab on Sharing and Circular Economy (LLSC) to point out possible future scenarios of urban sustainable policies. The case study is analysed in five sections: (1) the description of the new permanent laboratory proposed by the City of Turin; (2) the past experiences of Living Labs in Turin; (3) the birth of LLSC and the involvement strategy; (4) the introduction of the eight admitted experimentations. In the light of the results collected, the last paragraph (5) came up with the Strengths, Weaknesses, Opportunities, Treaths (SWOT) analysis in the LLSC. Eventually, it deals with the research question by offering a common ground for global and local policies focused on sustainability and CE.

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“…For the last 15 years the number of 3D structures of secondary transporters and other membrane proteins has been increasing drastically to more than 1100 unique structures. Along a steady amount of new structures solved by X-ray christallography, more and more structures are solved using cryo-EM, allowing identification of unique and common structural features (White, 2020).…”

Section: Secondary Active Transportersmentioning

confidence: 99%

Structural and functional insights into the citrate transporter SeCitS

Grötzinger¹

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Membrane proteins are a diverse group of proteins that serve a multitude of purposes with one of the most important ones being transport. All kinds of substrates are shuffled over biological membranes with the help of dedicated proteins enabling the transport along and against a concentration gradient. Within the group of actively transporting proteins a diverse set of proteins that rely on an electrochemical gradient to facilitate transport of a substrate against its concentration gradient can be found. Those so-called secondary active transporters are a group on integral membrane proteins ubiquitous to all cells. They allow the transport of all kinds of substrates like nutrients, ions, other metabolites and drugs over the hydrophobic barrier created by the cellular and organellar membrane. The gradients that provide the main driving force for most of the transporters are either sodium ions or protons, although transporters utilizing other ions or organic compounds are found as well. In case of exchangers two very similar substrates are transported in opposing direction over the membrane, one against its electrochemical gradient driven by the other. Along with a structural diversity of the transporters concerning overall shape, oligomerization and number of transmembrane elements comes a mechanistic variety though still following the principle of alternating access. In humans the malfunction of secondary active transporters can lead to a physiological disorders such as epilepsy, depression or obesity. The focus of this thesis was the structural and functional characterization of the secondary active transporter SeCitS from Salmonella enterica, a symporter of the 2-hydroxycarboxylate family. The transport of citrate as a bivalent ion is facilitated by the flux of sodium ions that have an inward-facing gradient over the inner membrane of Salmonella enterica. Transport experiments showed that the transport ratio is two sodium ions per citrate molecule, netting in an electroneutral transport. Compared to other members of the family the specificity of the transporter towards its main substrate is very high. Structural information on the protein was initially obtained through 2D electron crystallography, which allowed the identification of the oval shaped dimer and a first hint towards a significant conformational change that the protein undergoes during its transport cycle. Using 3D crystallography, the X-ray structure of the transporter was solved. The protein crystalizes as a stable, but conformationally asymmetric dimer. As bound citrate can be readily identified in both protomers they can be assigned into an outward- and an inward-facing conformation, with the main citrate binding site in the outward-facing conformation. One interesting feature of the crystal structure was the large surface available for multimerization, providing a platform for tight dimerization of the two protomers. On the other hand, SeCitS did not show a true cooperativity of transport. With those two aspects taken into account the question arose if any potential crosstalk between the monomers within the dimer takes place and influences transport (negative cooperativity) or the conformational distribution within the dimer (stabilization of the protein within the membrane). The functional approach in answering this question was the use of mutated variants of the protein for cross-linking within one monomer. Two residues were chosen respectively to lock one of either conformation to be able to test for transport activity in the remaining protomer. The suitability of the residues was derived from the crystal structure (D112 – R205 to lock the inward-facing conformation and L337 – S412 for the outward-facing conformation). After initial promising results the final variants were not stable enough to be analyzed in transport assays. To analyze the distribution of relative conformations within the dimer the protein was reconstituted into native-like lipid environment such as nanodiscs or saposin nanoparticles to be analyzed by cryo-electron microscopy. The first images were recorded and did yield promising 2D classes where the general features of the transporter were identified. Yet, an improved preparation is required to obtain a high resolution structure. The key functional aspects of a transporter are its ability to bind and transport its substrates. In a set of experiments those features were investigated by a radioligand transport assay and by isothermal titration calorimetry (ITC). The transport properties of the protein were assessed in a filter assay using a radioactively labeled citrate as a read-out. The protein was reconstituted into proteoliposomes and subjected to different substrate conditions. Different ions were tested in its ability to drive or inhibit transport, but only sodium ions were able to drive transport and also not hindered by the presence of other ions...

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https://www.rfbeditora.com/catalogo

Cited by 3 publications

References 0 publications

Field Testing of a Novel Drilling Technique to Expand Well Diameters at Depth in Unconsolidated Formations

Field Testing of a Novel Drilling Technique to Expand Well Diameters at Depth in Unconsolidated Formations

Living lab on sharing and circular economy: The case of Turin

Structural and functional insights into the citrate transporter SeCitS

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