Microstructural Characterization of Prefabricated Hempcrete Blocks

Sustainable building materials have been developed to reduce the polluting emissions and the exploitation of natural resources of the building sector. Among these materials, an outstanding category is that of nature-based solutions which are produced recovering waste or by-products of agricultural cultivations and using them as vegetal aggregates to replace the traditional ones. This paper focusses on hempcrete which is produced mixing the by-product of industrial hemp cultivation (i.e., shives) and lime to obtain a sustainable, breathable and insulating material. The strength of hempcrete develops through carbonation of the binder that, leading to the formation of calcium or magnesium carbonates and mineralization of shives, determines the microstructure and hence most of the characteristic properties of the material. The aim of this research is to investigate how carbonation influences the microstructure of hempcrete when different recipes are used for blocks production. This study consists in the characterization of the material through techniques such as XRD (X-ray Diffractometry), SEM (Scanning Electron Microscopy) and TG-DTG (thermogravimetric analyses). Moreover, the evolution of carbonation is studied analyzing samples at different maturation times. The investigation of the carbonation reaction degree is also crucial to evaluate the environmental performances of the material because it allows the quantification of the carbon dioxide uptake. Also, periodic characterization allows to assess the durability of hempcrete and to select the best formulation according to the designed application and the corresponding service conditions.

Novel Mathematical Method to Obtain the Optimum Speed and Fuel Reduction in Heavy Diesel Trucks

In Mexico and many parts of the world, land cargo transport units (UTTC) operate at high speeds, causing accidents, increased fuel costs, and high levels of polluting emissions in the atmosphere. The speed in road driving, by the carriers, has been a factor little studied; however, it causes serious damage. This problem is reflected in accidents, road damage, low efficiency in the life of the engine and tires, low fuel efficiency, and high polluting emissions, among others. The official Mexican standard NOM-012-SCT-2-2017 on the weight and maximum dimensions with which motor transport vehicles can circulate, which travel through the general communication routes of the federal jurisdiction, establishes the speed limit at the one to be driven by an operator. Because of the new reality, the uses and customs of truck operators have been affected, mainly in their operating expenses. In this work, a mathematical model is presented with which the optimum driving speed of a UTTC is obtained. The speed is obtained employing the equality between the forces required to move the motor unit and the force that the tractor has available. The required forces considered are the force on the slope, the aerodynamic force, and the friction force, and the force available was considered the engine torque. This mathematical method was tested in seven routes in Mexico, obtaining significant savings of fuel above 10%. However, the best performance route possesses 65% flat terrain and 35% hillocks without mountainous terrain, regular type of highway, and a load of 20,000 kg, where the savings increase up to 16.44%.

Accounting for Inequality Aversion Can Justify the 2◦ C Goal

Impact assessment models are a tool largely used to investigate the benefit of reducing polluting emissions and limiting the anthropogenic mean temperature rise. However, they have been often criticised for suggesting low levels of abatement. Countries and regions, that are generally the actors in these models, are usually depicted as having standard concave utility functions in consumption. This, however, disregards a potentially important aspect of environmental negotiations, namely its distributive implications. The present paper tries to fill this gap assuming that countries\regions have Fehr and Schmidt (1999) (F&S) utility functions, specifically tailored for including inequality aversion. Thereby, we propose a new method for the empirical estimation of the inequality aversion parameters by establishing a link between the well known concept of elasticity of marginal utility of consumption and the F&S utility functions, accounting for heterogeneity of countries/regions. By adopting the RICE model, we compare its standard results with the ones obtained introducing F&S utility functions, showing that, under optimal cooperation, the level of temperature rise is significantly lower in the last scenario. In particular, in the last year of the simulation, the optimal temperature rise is 2.1 ◦ C. Furthermore, it is shown that stable coalitions are easier to be achieved when F&S preferences are assumed, even if the advantageous inequality aversion parameter (altruism) is assumed to have a very low value. However, self–sustaining coalitions are far from reaching the environmental target of limiting the mean temperature rise below 2 ◦ C despite the adoption of F&S utility functions.

Potential Use of Native Yeasts to Produce Bioethanol and Other Byproducts from Black Sugarcane, an Alternative to Increment the Subsistence Farming in Northern Ecuador

The high consumption of energy, mainly in the automotive sector, is supplied by fossil fuels, which, when combusted, generate polluting gases leading to the great problem of climate change. This has led society to seek alternatives. Bioethanol is a biofuel that can be obtained from the fermentation of different raw materials rich in sucrose such as sugarcane, which can be mixed with gasoline and used to reduce polluting emissions. The following investigation focused on studying the efficiency of three selected native yeasts in the fermentation of black sugarcane POJ 27-14 variety juice to produce bioethanol and other byproducts of biotechnological interest. A comparison between the size of the inoculum of three selected native yeasts (Lev6, Lev9, and Lev30) and two reference commercial controls in the fermentation process was performed. The phylogenetic classification was carried out based on the analysis of the internal transcribed spacer 1 sequence, 5.8S ribosomal RNA, and internal transcribed spacer 2. Lev6 and Lev30 were classified as Saccharomyces cerevisiae, while Lev9 was Candida intermedia, with 99% nucleotide sequence identity. The results showed that the optimal growth temperature was 30 °C with constant agitation (200 rpm) for biomass production. The Lev30 strain presented the highest yield in the production of biomass from sugarcane juice fermentation, while the Lev6 strain presented the highest yield in ethanol production. Additionally, among native yeasts, Lev6 registered the highest ethanol concentration (Q) and volumetric productivity (Qp) values of 0.61 (g/L/h) and 43.92 g/L, respectively, which were comparable with the control yeasts. The gas chromatography coupled to mass spectrometry (GC-MS) indicated the presence of ethanol in all samples (98% to 99% relative percentages) along with some therapeutic substances such as (2-aziridinylethyl) amine and tetraacetyl-d-xylonic nitrile with greater efficiency than commercial controls from the alcoholic fermentation of black sugarcane juice.

Aspects Regarding Polluting Emissions to the Stack of Clincher Ovens in Romanian Cement Factories

The paper presents an analysis of the flow of flue gases and dust in the area of the clinker kiln and in the area of the flour mill, as well as emission data for the last three consecutive years at the flour mill stack - clinker kiln, from some cement factories in Romania. In general, both emissions of dust (total powders) and pollutant gases (SOx, NOx, CO, dioxins and furans, VOC, heavy metals, etc.) were within the permissible limits set out in the Integrated Environmental Permit of the individual plants.

The Trade-Off Between Tourism and Pollution for Japanese Economic Growth

This paper proposes a vector error correction model to investigate the relationship between polluting emissions and GDP levels in Japan, in the period 1970-2014, and tests the validity of the Environmental Kuznets Curve (EKC) hypothesis driven by tourist arrivals. Our results validate the existence of two different causality channels among the selected variables. In particular, we find that a trade-off might exist between increasing the number of tourists, which drives economic growth, and the pattern of a sustainable development, due to the increase of polluting emissions. The analysis allows us to propose appropriate policy strategies to promote a robust and sustainable long run economic growth.

Implementation of Electric Vehicles in The Internal Route of The International University of Ecuador

Sustainable campuses have become one of the main objectives of agendas for a wide range of universities as a result of the impacts generated by the activities carried out within an academic life and how they directly affect the environment. An important aspect of the educational model of the International University of Ecuador, considering education as a focal transforming point of collective change, is to teach values and responsibility for the environment, considering that in terms of sustainability a higher education should not be understood only from the technical point of view, but as a process of realizing the significance of substantial values that would encourage future professionals to commit to the construction of a more fair and equitable society. For this reason, the objective of this study is to analyze sustainability through the implementation of electric mass transport vehicles in the internal route of the International University of Ecuador, for which the methodology is based on a quantitative approach, whose type of study is exploratory and of an inductive-deductive nature, analyzing the variables that directly influence a sustainable environment such as altitude above sea level (geographical location), benefited people, consumption and routes. Instruments such as sampling and surveys will be used to determine the decrease in polluting emissions that can affect the natural environment of the area. The technical considerations are the following: the location of the campus presents average slopes of 7.76 ° at 2560 masl, the results of autonomy in a route are 14.8 km benefiting around 450 people a day from the university community, having an annual load consumption of 297311 KWh during day hours and of 114715 KWh during night hours. With the implementation of an electric vehicle for the internal route, a power of 154.7 KW is required to overcome a slope of 18 ° with a campus route of 178.4 km, with this it would stop emitting 29.6 tons of CO2 and 0.76 tons of gases harmful for the environment per year

A Methodology for Assessing Environmental Benefits from LNG Transition: The Case of Regione Sardegna

The use of Liquefied Natural Gas (LNG) is crucial for reaching the pollution reduction objectives that have been set by the new European laws. The widespread use of LNG allows for the reduction of air-polluting emissions in many fields, from residential to industrial and transport sectors. The European Project SIGNAL is aimed towards supporting and bolstering the diffusion of LNG usage, especially in port areas and in regions that are not connected to the main continental NG network (e.g. islands or border regions) where LNG is still a convenient alternative to the construction of distribution infrastructures. Considering that the impact of primary LNG consumption is strongly affected by the efficiency of technologies employed in energy conversion, it differs from sector to sector and from country to country. For this reason, it is useful to evaluate the environmental benefits deriving from the conversion to LNG fed technologies, to assess the effective emission reductions. In the present paper, a simple yet fast and reliable methodology to assess the environmental benefits is presented. The methodology is relying on the application of the Emission Factors available on the Emission Factor Database developed by the European Union, integrated with other national databases or literature studies, in case of lacking data. Moreover, in the present paper, the case study of Regione Sardegna is presented. Starting from the regional energy needs, it is possible to evaluate the current emissions levels amount for five selected pollutants (PM 2.5, PM10, CO, CO2, NOx, SOx). Then, two different scenarios are forecasted, with a 10-year timespan: a low LNG widespread and a high penetration one. Then, the emission levels for the two cases are evaluated and compared to the base case. Overall, the use of LNG is helpful towards the reduction of air emissions, especially for PM2.5, PM10, and SOx. The emissions for CO and NOx can anyway increase up to 5.5% when a single sector is analyzed, depending on the level of technology development of the considered sector.

Determination of laminar burning velocity of methane/air flames in sub atmospheric environments

The global energy demand enhances the environmental and operational benefits of natural gas as an energy alternative, due to its composition, mainly methane (CH4), it has low polluting emissions and benefits in energy and combustion systems. In the present work, the laminar burning velocity of methane was determined numerically and experimentally at two pressure conditions, 0.85 atm and 0.98 atm, corresponding to the city of Medellín and Caucasia, respectively, located in Colombia. The environmental conditions were 0.85 atm, 0.98 atm, and 295±1 K. The simulations and experimental measurements were carried out for different equivalence relations. Experimental laminar burning velocities were determined using the burner method and spontaneous chemiluminescence technique, flames were generated using burners with contoured rectangular ports to maintain laminar Reynolds numbers for the equivalence ratios under study and to reduce the effects of stretch and curvature in the direction of the burner's axis. In general, the laminar burning velocity fits well with the numerical results. With the results obtained, a correlation is proposed that relates the laminar burning velocity with the effects of pressure, in the form SL=aPb, where a and b are model constants. Sensitivity analysis was performed using the GRI-Mech 3.0 mechanism which showed that the most sensitive reaction was H+O2=O+OH (R38). Additionally, it was found that the reactions H+CH3 (+M)=CH4 (+M) (R52), 2CH3 (+M)=C2H6 (+M) (R158), and O+CH3=H+CH2O (R10) dominate the consumption of CH3 which is an important radical in the oxidation of methane, this analysis is carried out for equivalence ratios of 0.8 and 1.0, and atmospheric pressures of 0.85 atm and 0.98 atm