Applications of low enthalpy geothermal energy: the case of the Faculty of Physical and Mathematical Sciences at the University of Chile

In recent decades, the industry has observed a significant shift towards the use of renewable energy, such as solar, wind and geothermal. The Chilean scenario has not been an exception, and much progress has been made in sustainable energy prospection and implementation, especially in the electricity sector, where solar and wind power amount 2300 MW, and since April 2017, the first geothermal power plant (48 MW) has come into operation. In the area of low enthalpy geothermal energy, the use is around 19 MW. The Faculty of Physical and Mathematical Sciences at the University of Chile has been contributing to this transformational process, with its Sustainable Campus initiative. The first step of this initiative is the introduction of renewable energy on site, which has been achieved through the installation of a solar photovoltaic plant of 15 kW. Along this line, the design and implementation of a geothermal air conditioning system (HAVC) is underway, which will serve the classrooms and offices in the traditional engineering building of the campus. The technology to be used in this project is the Ground Heat Pump (GHP). The present paper includes an introduction of the applications of low enthalpy geothermal energy in Chile, a description of the Office of Engineering for Sustainable Development at the Faculty of Physical and Mathematical Sciences, and the design of a geothermal HAVC system in the university campus, considering economic, environmental, technical and social aspects. Besides the operation of the GHP, the system will be used for teaching purposes to incorporate sustainable development in the curriculum of the university. The expected savings of the geothermal system versus an aerothermal design are 41,070 kWh annually, considering both cooling and heating.This research was partially funded by the Andean Geothermal Center of Excellence (CEGA) and the Complex Engineering Systems Institute, ISCI (Project CONICYT: FB0816)

Plantas de cobertura de solo para sistema plantio direto.

A camada de palha, sobre o solo, e essencial para o sucesso do Sistema Plantio Direto (SPD). Cria um ambiente extremamente favoravel as condicoes fisicas, quimicas e biologicas do solo contribuindo para o controle de plantas daninhas, estabilizacao da producao e recuperacao ou manutencao da qualidade do solo. O sistema de rotacao e sucessao de culturas deve ser adequado para permitir a manutencao de uma cobertura minima do solo com palha. Na escolha destas plantas, e fator decisivo conhecer a sua adaptacao a regiao e sua habilidade em crescer num ambiente menos favoravel, uma vez que as culturas comerciais sao estabelecidas nas epocas mais propicias. Isto e especialmente verdade nas condicoes de Brasil Central, onde o inverno e seco, ao passo que na regiao Sul, de inverno umido, nao existe essa limitacao e ha maior opcao de plantas adaptadas as condicoes do inverno. Existem muitas plantas de cobertura para as diferentes regioes edafoclimaticas do Brasil, e a experiencia local e decisiva nesta selecao. Em qualquer situacao, deve-se ter sempre em mente que nao existe uma planta milagrosa e que o ideal e ter mais de uma dessas especies no sistema de producao, onde busca-se aliar renda a preservacao ambiental

Comparison of microstructure and mechanical properties at different length scales of WC-Co hardmetals consolidated by binder jetting 3D printing and hip

Additive Manufacturing (AM) is rapidly growing as a revolutionary technique. It provides an interesting ability to produce complex geometries, a key feature for enhancing performance and widening application fields of hardmetal components, limited characteristic for traditional processing techniques. Within this context, it is necessary to study the mechanical integrity of samples produced by AM [AMed] where it is expected to find characteristics linked to the shaping route followed, and study if they will have influence on the final behaviour regarding the mechanical properties expect for a specimen process by a traditional manufacturing route. This work aims to study the final microstructure, mechanical properties and layer assemblage at different length scales for a 12%wtCo– WC grade hardmetals of medium grain size consolidated by binder jetting 3DP and subsequent SinterHIP. In addition, compare this results with the ones obtained from a 12%wtCo–WC specimens process by means of a traditional technique like Hot Isostatic Pressing (HIP) using the same raw material like in the AMed specimens. Hardness Vickers at macro- and microlength scale as well as scratch tests, using different loads and indenter tips, are conducted on both type of samples. The results are analysed and discussed in terms of oriented layer-like material assemblage effects on microstructural variability, mechanical response determined by intrinsic physical behaviour of the material and feedstock used

Rethinking Hypothesis Tests

Null Hypothesis Significance Testing (NHST) have been a popular statistical tool across various scientific disciplines since the 1920s. However, the exclusive reliance on a p-value threshold of 0.05 has recently come under criticism; in particular, it is argued to have contributed significantly to the reproducibility crisis. We revisit some of the main issues associated with NHST and propose an alternative approach that is easy to implement and can address these concerns. Our proposed approach builds on equivalence tests and three-way decision procedures, which offer several advantages over the traditional NHST. We demonstrate the efficacy of our approach on real-world examples and show that it has many desirable properties

Understanding Postprandial Inflammation and Its Relationship to Lifestyle Behaviour and Metabolic Diseases

Postprandial hyperlipidemia with accumulation of remnant lipoproteins is a common metabolic disturbance associated with atherosclerosis and vascular dysfunction, particularly during chronic disease states such as obesity, the metabolic syndrome and, diabetes. Remnant lipoproteins become attached to the vascular wall, where they can penetrate intact endothelium causing foam cell formation. Postprandial remnant lipoproteins can activate circulating leukocytes, upregulate the expression of endothelial adhesion molecules, facilitate adhesion and migration of inflammatory cells into the subendothelial space, and activate the complement system. Since humans are postprandial most of the day, the continuous generation of remnants after each meal may be one of the triggers for the development of atherosclerosis. Modulation of postprandial lipemia by lifestyle changes and pharmacological interventions could result in a further decrease of cardiovascular mortality and morbidity. This paper will provide an update on current concepts concerning the relationship between postprandial lipemia, inflammation, vascular function, and therapeutic options

Discovery of the acetyl cation, CH3CO+, in space and in the laboratory

Using the Yebes 40m and IRAM 30m radiotelescopes, we detected two series of harmonically related lines in space that can be fitted to a symmetric rotor. The lines have been seen towards the cold dense cores TMC-1, L483, L1527, and L1544. High level of theory ab initio calculations indicate that the best possible candidate is the acetyl cation, CH3CO+, which is the most stable product resulting from the protonation of ketene. We have produced this species in the laboratory and observed its rotational transitions Ju = 10 up to Ju = 27. Hence, we report the discovery of CH3CO+ in space based on our observations, theoretical calculations, and laboratory experiments. The derived rotational and distortion constants allow us to predict the spectrum of CH3CO+ with high accuracy up to 500 GHz. We derive an abundance ratio N(H2CCO)/N(CH3CO+) = 44. The high abundance of the protonated form of H2CCO is due to the high proton affinity of the neutral species. The other isomer, H2CCOH+, is found to be 178.9 kJ/mol above CH3CO+. The observed intensity ratio between the K=0 and K=1 lines, 2.2, strongly suggests that the A and E symmetry states have suffered interconversion processes due to collisions with H and/or H2, or during their formation through the reaction of H3+ with H2CCO.Comment: Accepted for publication in A&A Letter

Front Matter

The carbohydrate Galα1-3Galβ1-(3)4GlcNAc-R (α-Gal) is produced in all mammals except for humans, apes and old world monkeys that lost the ability to synthetize this carbohydrate. Therefore, humans can produce high antibody titers against α-Gal. Anti-α-Gal IgE antibodies have been associated with tick-induced allergy (i.e. α-Gal syndrome) and anti-α-Gal IgG/IgM antibodies may be involved in protection against malaria, leishmaniasis and Chagas disease. The α-Gal on tick salivary proteins plays an important role in the etiology of the α-Gal syndrome. However, whether ticks are able to produce endogenous α-Gal remains currently unknown. In this study, the Ixodes scapularis genome was searched for galactosyltransferases and three genes were identified as potentially involved in the synthesis of α-Gal. Heterologous gene expression in α-Gal-negative cells and gene knockdown in ticks confirmed that these genes were involved in α-Gal synthesis and are essential for tick feeding. Furthermore, these genes were shown to play an important role in tick-pathogen interactions. Results suggested that tick cells increased α-Gal levels in response to Anaplasma phagocytophilum infection to control bacterial infection. These results provided the molecular basis of endogenous α-Gal production in ticks and suggested that tick galactosyltransferases are involved in vector development, tick-pathogen interactions and possibly the etiology of α-Gal syndrome in humans.This research was supported by the Consejería de Educación, Cultura y Deportes, JCCM, Spain, project CCM17-PIC-036 (SBPLY/17/180501/000185). JJV was supported by Project FIT (Pharmacology, Immunotherapy, nanoToxicology), funded by the European Regional Development Fund.Peer Reviewe

Phloem-feeding herbivory on flowering melon plants enhances attraction of parasitoids by shifting floral to defensive volatiles.

Emission of herbivore-induced plant volatiles (HIPVs) can differ according to the type of herbivory and the plant development stage, ultimately affecting recruitment of the natural enemy. Little is known about plant defenses induced at the flowering stage by phloem-feeding insects. We investigated the olfactory preference of Encarsia desantisi parasitoids and the chemical profile of flowering melon plants induced or not by the phloem-feeding of Bemisia tabaci whiteflies. In addition, we tested whether the parasitoids were attracted to synthetic defensive HIPVs, which mimicked whitefly-infested flowering melons. The parasitoids recognized volatiles from undamaged melons but preferred the scent of host-infested melons in olfactometry assays. Amounts of most individual volatiles did not differ between plant treatments; however, only whitefly-induced melons released methyl salicylate and tetradecane, compounds known to attract parasitoids. Interestingly, grouping volatiles by chemical classes revealed that whitefly-infested melon released larger amounts of monoterpenes and smaller amounts of benzenoids than undamaged melons, which might underlying the parasitoid attraction and indicate a possible trade-off between defensive and reproductive defenses at the melon flowering stage. Additionally, E. desantisi preferred the mix of synthetic and defensive HIPVs over hexane (control), opening a new avenue for further investigations in using olfactory lures for B. tabaci biological control. This study is the first report of induced defenses in melon plants and their mediation in a tritrophic interaction, as well as the first record of E. desantisi behavioral preference for HIPVs

Necklace-structured high-harmonic generation for low-divergence, soft x-ray harmonic combs with tunable line spacing

The extreme nonlinear optical process of high-harmonic generation (HHG) makes it possible to map the properties of a laser beam onto a radiating electron wave function and, in turn, onto the emitted x-ray light. Bright HHG beams typically emerge from a longitudinal phased distribution of atomic-scale quantum antennae. Here, we form a transverse necklace-shaped phased array of linearly polarized HHG emitters, where orbital angular momentum conservation allows us to tune the line spacing and divergence properties of extreme ultraviolet and soft x-ray high-harmonic combs. The on-axis HHG emission has extremely low divergence, well below that obtained when using Gaussian driving beams, which further decreases with harmonic order. This work provides a new degree of freedom for the design of harmonic combs—particularly in the soft x-ray regime, where very limited options are available. Such harmonic beams can enable more sensitive probes of the fastest correlated charge and spin dynamics in molecules, nanoparticles, and materials.The JILA team graciously acknowledges support from the Department of Energy BES Award No. DE-FG02-99ER14982 for the experimental implementation, a MURI grant from the Air Force Office of Scientific Research under Award No. FA9550-16-1-0121 for the mid-infrared laser soft x-ray research, and a National Science Foundation Physics Frontier Center grant PHY-1734006 for theory. N.J.B. acknowledges support from National Science FoundationGraduate Research Fellowships (grant no. DGE-1650115). Q.L.D.N. acknowledges support from National Science Foundation Graduate Research Fellowships (grant no. DGE-1144083). J.S.R., L.P., and C.H.-G. acknowledge support from Ministerio de Ciencia e Innovación (FIS2016-75652-Pand PID2019-106910GB-I00). This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (grant agreement no. 851201). J.S.R., L.P., and C.H.-G. also acknowledge support from Junta de Castilla y León FEDER funds (project no. SA287P18). L.R. acknowledges support from Ministerio de Educación, Cultura y Deporte (FPU16/02591). C.H.-G. acknowledges Ministerio de Ciencia, Innovación, y Universidades for Ramón y Cajal contract (RYC-2017-22745), cofunded by the European Social Fund. L.R., J.S.R., L.P., and C.H.-G. thankfully acknowledge the computer resources at MareNostrum and the technical support provided by Barcelona Supercomputing Center (FI-2020-3-0013)

Fabrication and arc erosion behavior of Ag-SnO2-ZnO electrical contact materials

This study investigated the synthesis of Ag-SnO2-ZnO by powder metallurgy methods and their subsequent electrical contact behavior. The pieces of Lambda g-SnO2-ZnO were prepared by ball milling and hot pressing. The arc erosion behavior of the material was evaluated using homemade equipment. The microstructure and phase evolution of the materials were investigated through X-ray diffraction, energy-dispersive spectroscopy and scanning electron microscopy. The results showed that, although the mass loss of the Ag-SnO2-ZnO composite (9.08 mg) during the electrical contact test was higher than that of the commercial Ag-CdO (1.42 mg), its electrical conductivity remained constant (26.9 +/- 1.5% IACS). This fact would be related to the reaction of Zn2SnO4's formation on the material's surface via electric arc. This reaction would play an important role in controlling the surface segregation and subsequent loss of electrical conductivity of this type of composite, thus enabling the development of a new electrical contact material to replace the non-environmentally friendly Ag-CdO composite