Mechanical behavior of hot-mix asphalt made with recycled concrete aggregates from construction and demolition waste: a design of experiments approach

[Abstract:] The present work is a re-evaluation of previous research on the durability of hot-mix asphalt made with recycled concrete aggregates from construction and demolition waste (CDW) with a different approach. Response surface methodology (RSM) was used to conduct this study. The kind of natural aggregates (schist and calcite-dolomite), the recycled concrete aggregates percentage (0%, 20%, 40% and 60%) and the water saturation (0% and 100%) were the pertinent factors for this methodology. Indirect tensile stress (ITS) was determined in mixtures fabricated with 0%, 20%, 40% and 60% recycled concrete aggregates. According to the results, the ITS of the bituminous mixtures increases as the percentage of recycled concrete aggregate increases. This behavior is more significant when calcite-dolomite is used as a natural aggregate. Water saturation has the same influence in both natural aggregates. The indirect tensile strength ratio (ITSR) was calculated to evaluate the stripping potential. According to the Spanish specifications, the results suggest that the percentage of CDW that can be used for hot mixes is 17% when schist is used as natural aggregate and 14% for calcite-dolomite

Evaluation of the Resilient Modulus of Hot-Mix Asphalt Made With Recycled Concrete Aggregates From Construction and Demolition Waste

[Abstract] This paper reports the influence of the percentage of recycled aggregate (RCA) from construction and demolition waste (C&DW) together with the percentage of binder (L), curing time (t) and temperature (T) of the samples on the stiffness of a hot asphalt mixture. The study was carried out using the response surface methodology (RSM). The resilient modulus was chosen to estimate the stiffness of the mixture. The percentages of RCA studied were 0% (control), 5%, 10%, 20% and 30%, whilst 3.5%, 4% and 4.5% were those chosen for the binder content. Before compacting the samples, they were left into the oven to cure. Curing time, or pretreatment time, were set at 0 (control), 2 and 4 h. The samples were subjected to temperatures of 0, 10 and 20 °C. The natural aggregate is of the hornfels type. All the specimens studied showed high stiffness at low temperatures. According to this research, temperature proved to be the most influential factor on the decrease in the resilient modulus and, conversely, the percentage of recycled aggregate is not a significant factor in the range of values studied.Portugal. Fundação para a Ciência e Tecnologia; UIDB/04730/202

Copper‐Catalyzed Selective Pyrrole Functionalization by Carbene Transfer Reaction

1H‐Pyrroles can be directly functionalized by means of the incorporation of carbene groups from diazo compounds, in a process catalyzed by TpxCu complexes (Tpx=hydrotrispyrazolylborate ligand). The reactions take place with a complete selectivity toward the formal insertion of the carbene into the Cα−H bond, leading to alkylated pyrroles, with no modification of the Cβ−H, N−H or C=C bonds of the pyrrole unit. Alkyl substituents at C‐ring as well as alkyl, aryl, allyl or alkyne substitution at N atom are tolerated, the strategy affording 20 new pyrrole derivatives. The observance of partial deuteration at the methylene group when the reaction is carried out with added D2O serves to discard the direct insertion of the carbene group into the Csp2−H bond, the alternative electrophilic attack to the pyrrole ring being feasible.Support for this work was provided by the MINECO (CTQ2017- 82893-C2-1-R and PO FEDER 2014-2020, UHU-1254043). AMR thanks MINECO for a FPU fellowship

Pyrrole Functionalization by Copper‐Catalyzed Nitrene Transfer Reactions

The catalytic functionalization of pyrroles by incorporation of a nitrene group is reported. The Cα‐H bond of 1H‐pyrrole is amidated upon the formal insertion of the NTs (Ts=p‐toluenesulfonyl) group catalyzed by TpBr3Cu(NCMe) (TpBr3=hydrotris(3,4,5‐tribromo‐pyrazolyl)borate). N‐substituted pyrroles also verify the same transformation. The mechanism proposal is similar to that previously described for benzene amidation with the same catalyst and PhI=NTs, which takes place through aziridine formation, ring opening and 1,2‐hydrogen shift. A cascade reaction involving the coupling of 2,5‐dimethylfuran, 1,2,3‐trimethyl‐pyrrole and a nitrene NTs group is also described, leading to a 1,2‐dihydropyridine‐imine compound.Support for this work was provided by the MINECO (CTQ2017‐82893‐C2‐1‐R and PO FEDER 2014‐2020, UHU‐1254043). AMR and MRR thanks MEC for a FPU fellowships

Role of conservative management in traumatic aortic injury: comparison of long-term results of conservative, surgical, and endovascular treatment

[Abstract] Objective. The purpose of this study is to compare early and long-term results in terms of survival and cardiovascular complications of patients with acute traumatic aortic injury who were conservatively managed with patients who underwent surgical or endovascular repair. Methods. From January 1980 to December 2009, 66 patients with acute traumatic aortic injury were divided into 3 groups according to treatment intention at admission: 37 patients in a conservative group, 22 patients in a surgical group, and 7 patients in an endovascular group. Groups were similar with regard to gender, age, Injury Severity Score, Revised Trauma Score, and Trauma Injury Severity Score. Results. In-hospital mortality was 21.6% in the conservative group, 22.7% in the surgical group, and 14.3% in the endovascular group (P = .57). In-hospital aortic-related complications occurred only in the conservative group. Median follow-up time was 75 months (range, 5–327 months). Conservative group survival was 75.6% at 1 year, 72.3% at 5 years, and 66.7% at 10 years. Surgical group survival remained at 77.2% at 1, 5, and 10 years, whereas survival in the endovascular group was 85.7% at 1 and 5 years (P = .18). No patient in the surgical or endovascular group required reintervention because of aortic-related complications, whereas 37.9% of the conservative group had an aortic-related complication that required surgery or caused the patient’s death during the follow-up period. Cumulative survival free from aortic-related complications in the conservative group was 93% at 1 year, 88.5% at 5 years, and 51.2% at 10 years. Cox regression confirmed the initial type of aortic lesion (hazard ratio, 2.94; P = .002) and a Trauma Score-Injury Severity Score greater than 50% on admission (hazard ratio, 1.49; P = .042) as risk factors for the appearance of aortic-related complications. Two peaks in the complication rate of the conservative group were detected in the first week and between the first and third months after blunt thoracic trauma. Conclusions. The advent of thoracic aortic endografting has enabled a revolution in the management of acute traumatic aortic injury in patients with multisystem trauma with a low in-hospital morbimortality. Nonoperative management may be only a therapeutic option with acceptable survival in carefully selected patients. The natural history of these patients has revealed a marked trend of late aortic-related complications developing, which may justify an endovascular repair even in some low-risk patients

Use of Aerial Thermal Imaging to Assess Water Status Variability in Hedgerow Olive Orchards

Characterization of the spatial variability in tree water status is a prerequisite to conduct precise irrigation management within an orchard. This study assessed the suitability of a crop water stress index (CWSI) derived from high-resolution aerial thermal imagery to estimate tree water status variability in super high density (SHD) olive orchards. The experiment was conducted at a commercial SHD olive orchard near Seville (southwestern Spain). The drip irrigated trees were submitted to three irrigation regimes (four plots per treatment): a full irrigation treatment replacing the crop water needs (ETc) and two regulated deficit irrigation treatments replacing ca. 45% of ETc. During the irrigation season, meteorological variables, soil moisture content, leaf water potential and leaf gas exchange measurements were performed. Infrared temperature sensors (IRTS) installed about 1 m above the canopies were used to derive the required baselines for CWSI calculation. A thermal camera installed on a mini RPAS (Remote Piloted Aerial System) allowed recording high-resolution thermal images at 5 representative dates of the olive tree growing season. CWSI values derived from aerial thermal imagery were sensitive to the deliberately imposed variations in tree water status within the SHD olive orchard. Maximum stomatal conductance and midday stem water potential showed tight correlations with CWSI. We conclude that high resolution thermal imagery captured from a mini RPAS has proven to be a suitable tool to capture tree water status variability within SHD olive orchards.Ministerio de Economía y Competitividad AGL2012- 34544/ECOLIMAJunta de Andalucía P12-AGR-122