Manufacture and performance of lightweight aggregate from waste drill cuttings

This research investigated the technical feasibility of transforming waste drill cuttings into lightweight aggregate. Drill cuttings produced from the North Sea oil field were dried, ball milled, formed into pellets and fired at temperatures between 1160 and 1190 °C. Physical properties of the manufactured lightweight aggregate, including particle density, water absorption and compressive strength, were determined. The drill cuttings had a typical evaporite composition containing high concentrations of chloride salts. This limits the potential for using the as-received drill cutting samples in lightweight aggregate production as the products formed show high levels of leaching. The addition of a washing pre-treatment to reduce the leaching of chloride ions was necessary. Washing also reduced the initial sintering temperature and improved lightweight aggregate properties. Sintering at 1180 °C produced lightweight aggregate with particle density of 1.29 g/cm³, water absorption of 3.6% and compressive strengths of 4.4 MPa. The research showed that lightweight aggregate manufacturing represents a resource efficient option for the reuse of waste drill cuttings and provides significant material saving and landfill diversion

Up-Cycling Waste Glass to Minimal Water Adsorption/Absorption Lightweight Aggregate by Rapid Low Temperature Sintering: Optimization by Dual Process-Mixture Response Surface Methodology

Mixed color waste glass extracted from municipal solid waste is either not recycled, in which case it is an environmental and financial liability, or it is used in relatively low value applications such as normal weight aggregate. Here, we report on converting it into a novel glass-ceramic lightweight aggregate (LWA), potentially suitable for high added value applications in structural concrete (upcycling). The artificial LWA particles were formed by rapidly sintering (<10 min) waste glass powder with clay mixes using sodium silicate as binder and borate salt as flux. Composition and processing were optimized using response surface methodology (RSM) modeling, and specifically (i) a combined process-mixture dual RSM, and (ii) multiobjective optimization functions. The optimization considered raw materials and energy costs. Mineralogical and physical transformations occur during sintering and a cellular vesicular glass-ceramic composite microstructure is formed, with strong correlations existing between bloating/shrinkage during sintering, density and water adsorption/absorption. The diametrical expansion could be effectively modeled via the RSM and controlled to meet a wide range of specifications; here we optimized for LWA structural concrete. The optimally designed LWA is sintered in comparatively low temperatures (825-835 °C), thus potentially saving costs and lowering emissions; it had exceptionally low water adsorption/absorption (6.1-7.2% w/wd; optimization target: 1.5-7.5% w/wd); while remaining substantially lightweight (density: 1.24-1.28 g.cm-3; target: 0.9-1.3 g.cm-3). This is a considerable advancement for designing effective environmentally friendly lightweight concrete constructions, and boosting resource efficiency of waste glass flows

Solution and Solid-State Characterization of Zn(II) Complexes Containing A New Tridentate N\u3csub\u3e2\u3c/sub\u3es Ligand

A new N2S ligand bis(pyridyl)(2-mercapto-1-methylimidazolyl)methane (2, Py2MeImS) has been synthesized and characterized. Treatment of this ligand with bromide and triflate salts of Zn(II) results in the complexes (Py2MeImS)ZnBr2 (3) and [(Py2MeImS)2Zn](OTf)2 (4), respectively. The solid-state structure of (Py2MeImS)ZnBr2 shows bidentate N,N-coordination of Py2MeImS to the zinc ion, with the sulfur atom of the 2-mercaptoimidazole moiety uncoordinated. Two conformers of 3 rapidly interconvert in solution at room temperature, and variable temperature NMR studies and DFT calculations were used to help assign the likely identity of these conformers. In contrast, the crystal structure of [(Py2MeImS)2Zn] (OTf)2 exhibits a zinc ion with a distorted octahedral geometry where the two sulfur atoms of the two ligands are coordinated to the zinc center in a cis-configuration. Even though the cis-isomer (4-cis) is calculated to be lower in energy than the trans-isomer (4-trans), the low temperature 1H NMR spectrum of 4 reveals a single symmetric species that is inconsistent with the cis-isomer observed in the solid-state structure. DFT calculations propose alternative higher energy structures, including a trans-configuration of the coordinated S-atoms of the two Py2MeImS ligands, as well as structures in which the 2-mercaptoimidazole groups are no longer coordinated to the zinc(II) center. These studies provide valuable insight into the potential binding modes of this new ligand and its behavior in solution

Defining the Functional Domain of Programmed Cell Death 10 through Its Interactions with Phosphatidylinositol-3,4,5-Trisphosphate

Cerebral cavernous malformations (CCM) are vascular abnormalities of the central nervous system predisposing blood vessels to leakage, leading to hemorrhagic stroke. Three genes, Krit1 (CCM1), OSM (CCM2), and PDCD10 (CCM3) are involved in CCM development. PDCD10 binds specifically to PtdIns(3,4,5)P3 and OSM. Using threading analysis and multi-template modeling, we constructed a three-dimensional model of PDCD10. PDCD10 appears to be a six-helical-bundle protein formed by two heptad-repeat-hairpin structures (α1–3 and α4–6) sharing the closest 3D homology with the bacterial phosphate transporter, PhoU. We identified a stretch of five lysines forming an amphipathic helix, a potential PtdIns(3,4,5)P3 binding site, in the α5 helix. We generated a recombinant wild-type (WT) and three PDCD10 mutants that have two (Δ2KA), three (Δ3KA), and five (Δ5KA) K to A mutations. Δ2KA and Δ3KA mutants hypothetically lack binding residues to PtdIns(3,4,5)P3 at the beginning and the end of predicted helix, while Δ5KA completely lacks all predicted binding residues. The WT, Δ2KA, and Δ3KA mutants maintain their binding to PtdIns(3,4,5)P3. Only the Δ5KA abolishes binding to PtdIns(3,4,5)P3. Both Δ5KA and WT show similar secondary and tertiary structures; however, Δ5KA does not bind to OSM. When WT and Δ5KA are co-expressed with membrane-bound constitutively-active PI3 kinase (p110-CAAX), the majority of the WT is co-localized with p110-CAAX at the plasma membrane where PtdIns(3,4,5)P3 is presumably abundant. In contrast, the Δ5KA remains in the cytoplasm and is not present in the plasma membrane. Combining computational modeling and biological data, we propose that the CCM protein complex functions in the PI3K signaling pathway through the interaction between PDCD10 and PtdIns(3,4,5)P3

Prehospital transdermal glyceryl trinitrate in patients with ultra-acute presumed stroke (RIGHT-2): an ambulance-based, randomised, sham-controlled, blinded, phase 3 trial

Background High blood pressure is common in acute stroke and is a predictor of poor outcome; however, large trials of lowering blood pressure have given variable results, and the management of high blood pressure in ultra-acute stroke remains unclear. We investigated whether transdermal glyceryl trinitrate (GTN; also known as nitroglycerin), a nitric oxide donor, might improve outcome when administered very early after stroke onset. Methods We did a multicentre, paramedic-delivered, ambulance-based, prospective, randomised, sham-controlled, blinded-endpoint, phase 3 trial in adults with presumed stroke within 4 h of onset, face-arm-speech-time score of 2 or 3, and systolic blood pressure 120 mm Hg or higher. Participants were randomly assigned (1:1) to receive transdermal GTN (5 mg once daily for 4 days; the GTN group) or a similar sham dressing (the sham group) in UK based ambulances by paramedics, with treatment continued in hospital. Paramedics were unmasked to treatment, whereas participants were masked. The primary outcome was the 7-level modified Rankin Scale (mRS; a measure of functional outcome) at 90 days, assessed by central telephone follow-up with masking to treatment. Analysis was hierarchical, first in participants with a confirmed stroke or transient ischaemic attack (cohort 1), and then in all participants who were randomly assigned (intention to treat, cohort 2) according to the statistical analysis plan. This trial is registered with ISRCTN, number ISRCTN26986053. Findings Between Oct 22, 2015, and May 23, 2018, 516 paramedics from eight UK ambulance services recruited 1149 participants (n=568 in the GTN group, n=581 in the sham group). The median time to randomisation was 71 min (IQR 45–116). 597 (52%) patients had ischaemic stroke, 145 (13%) had intracerebral haemorrhage, 109 (9%) had transient ischaemic attack, and 297 (26%) had a non-stroke mimic at the final diagnosis of the index event. In the GTN group, participants’ systolic blood pressure was lowered by 5·8 mm Hg compared with the sham group (p<0·0001), and diastolic blood pressure was lowered by 2·6 mm Hg (p=0·0026) at hospital admission. We found no difference in mRS between the groups in participants with a final diagnosis of stroke or transient ischaemic stroke (cohort 1): 3 (IQR 2–5; n=420) in the GTN group versus 3 (2–5; n=408) in the sham group, adjusted common odds ratio for poor outcome 1·25 (95% CI 0·97–1·60; p=0·083); we also found no difference in mRS between all patients (cohort 2: 3 [2–5]; n=544, in the GTN group vs 3 [2–5]; n=558, in the sham group; 1·04 [0·84–1·29]; p=0·69). We found no difference in secondary outcomes, death (treatment-related deaths: 36 in the GTN group vs 23 in the sham group [p=0·091]), or serious adverse events (188 in the GTN group vs 170 in the sham group [p=0·16]) between treatment groups. Interpretation Prehospital treatment with transdermal GTN does not seem to improve functional outcome in patients with presumed stroke. It is feasible for UK paramedics to obtain consent and treat patients with stroke in the ultraacute prehospital setting. Funding British Heart Foundation

Manufacture and performance of lightweight aggregate from waste drill cuttings

This research investigated the technical feasibility of transforming waste drill cuttings into lightweight aggregate. Drill cuttings produced from the North Sea oil field were dried, ball milled, formed into pellets and fired at temperatures between 1160 and 1190 °C. Physical properties of the manufactured lightweight aggregate, including particle density, water absorption and compressive strength, were determined. The drill cuttings had a typical evaporite composition containing high concentrations of chloride salts. This limits the potential for using the as-received drill cutting samples in lightweight aggregate production as the products formed show high levels of leaching. The addition of a washing pre-treatment to reduce the leaching of chloride ions was necessary. Washing also reduced the initial sintering temperature and improved lightweight aggregate properties. Sintering at 1180 °C produced lightweight aggregate with particle density of 1.29 g/cm³, water absorption of 3.6% and compressive strengths of 4.4 MPa. The research showed that lightweight aggregate manufacturing represents a resource efficient option for the reuse of waste drill cuttings and provides significant material saving and landfill diversion

New synthetic glass-based supplementary cementitious materials derived from basalt composition

Abstract The cement industry faces an increasing demand for new supplementary cementitious materials (SCMs) as alternative to slags and ashes, the sources of which are in continuous depletion. This study reports on the characteristics of synthetic aluminosilicate glasses derived from basalt composition (BGs) as new SCMs. The pozzolanic activity of the developed glasses as well as their influence on the hydration kinetics, microstructure, and mechanical properties of blended cements are reported. The obtained results show that pastes containing BGs demonstrated faster hydration rate and higher compressive strength compared to those containing commonly applied granulated blast furnace slag (GBFS). In addition, the developed glasses demonstrated higher pozzolanic activity than GBFS as demonstrated form the measured amount of portlandite and strength activity index. The developed glasses can be obtained from earth abundant carbon-free raw materials as it is similar in composition to basalt. Therefore, this novel approach has potential to provide low-carbon cementitious binders for the concrete industry