• Energy Research
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Since long ago, pelagic Sargassum mats have been known to be abundant in the Sargasso Sea, where they provide habitat to diverse organisms. However, over the last few years, massive amounts of pelagic Sargassum have reached the coast of several countries in the Caribbean and West Africa, causing economic and environmental problems. Aiming for lessening the impacts of the blooms, governments and private companies remove the seaweeds from the shore, but this process results expensive. The valorization of this abundant biomass can render Sargassum tides into an economic opportunity and concurrently solve their associated environmental problems. Despite the diverse fields where algae have found applications and the relevance of this recurrent situation, Sargassum biomass remains without large scale applications. Therefore, this review aims to present the potential uses of these algae, identifying the limitations that must be assessed to effectively valorize this bioresource. Due to the constraints identified for each of the presented applications, it is concluded that a biorefinery approach should be developed to effectively valorize this abundant biomass. However, there is an urgent need for investigations focusing on holopelagic Sargassum to be able to truly valorize this seaweed.

Rapid urbanization combined with high economic growth, industrialization, and changes in socio-economic conditions increase the quantity of municipal solid waste. Cities located in South-Asia are facing serious issues due to waste, with countries like India, Bangladesh, and Pakistan top of the list of bad waste management. The increasing generation of solid waste and also the improper management of waste in Bangladesh leads to environmental degradation. Current waste management practice in Bangladesh is so weak that day by day it is harming the climate and creating a lot of unwanted situations. This research consists of an examination of the current administrative measures and presents another proposition for the executive cycle to decrease ecological contamination. The research study aims to decrease the amount of waste being dumped into municipal sanitary landfill sites & converting the waste into energy which is both financially and environmentally suitable by involving unemployed people in the management system. The results of this study will give an idea of how waste can be utilized as a resource and how this resource can be a capital good as well as how the local level problems can be solved by taking some strategies and making our environment suitable for future generations.

Radiative heat transfer in a 1 kW cavity-type solar reactor devoted to the thermal reduction of compressed ZnO and SnO2 powders is analyzed by a Monte Carlo ray tracing simulation. The developed model takes into account the radiative properties of the reactant particles and of the ceramic cavity walls, as well as the angular intensity distribution of the incoming concentrated solar irradiation. The model also includes the conduction heat losses through the lateral walls and the energy consumed by the endothermic chemical reaction. It is used to predict the temperature and the absorbed flux density profiles on the inner cavity walls for different main features of the reactor, concerning the dimensions of the cavity and the type of reactant. Results show that the absorbed flux density profile and the theoretical thermochemical efficiency change with the cavity aspect ratio and with the oxide reactant. The cavity with an aspect ratio of 3 and a SnO2 pellet undergoing dissociation presents the highest thermochemical efficiency. Additionally, a different configuration of the reactor design is considered, which consists in implementing a layer of reactive particles on the inner lateral cavity wall. The model highlights that this type of reactor operation with a reactant layer on the lateral cavity wall results in an improved thermochemical efficiency.

1. Natural populations deliver a wide range of products that provide income for millions of people and need to be exploited sustainably. Large heterogeneity in individual performance within these exploited populations has the potential to improve population recovery after exploitation and thus help sustaining yields over time. 2. We explored the potential of using individual heterogeneity to design smarter harvest schemes, by sparing individuals that contribute most to future productivity and population growth, using the understorey palm Chamaedorea elegans as a model system. Leaves of this palm are an important non-timber forest product and long-term inter-individual growth variability can be evaluated from internode lengths. 3. We studied a population of 830 individuals, half of which was subjected to a 67 % defoliation treatment for three years. We measured effects of defoliation on vital rates and leaf size – a trait that determines marketability. We constructed integral projection models in which vital rates depended on stem length, past growth rate, and defoliation, and evaluated transient population dynamics to quantify population development and leaf yield. We then simulated scenarios in which we spared individuals that were either most important for population growth or had leaves smaller than marketable size. 4. Individuals varying in size or past growth rate responded similarly to leaf harvesting in terms of growth and reproduction. By contrast, defoliation-induced reduction in survival chance was smaller in large individuals than in small ones. Simulations showed that harvest-induced population decline was much reduced when individuals from size and past growth classes that contributed most to population growth were spared. Under this scenario cumulative leaf harvest over 20 years was somewhat reduced, but long-term leaf production was sustained. A three-fold increase in leaf yield was generated when individuals with small leaves are spared. 5. Synthesis and applications This study demonstrates the potential to create smarter systems of palm leaf harvest by accounting for individual heterogeneity within exploited populations. Sparing individuals that contribute most to population growth ensured sustained leaf production over time. The concepts and methods presented here are generally applicable to exploited plant and animal species which exhibit considerable individual heterogeneity. Vital rate and internode dataThis data file contains annual vital rate data (stem length growth, fruit production, survival and leaf production) of 830 individuals of the understorey palm Chamaedorea elegans, collected in a 0.7 ha plot in Chiapas, Mexico, during the period November 2012 - November 2015. A 2/3 defoliation treatment was repeatedly applied to half of the individuals. The data file also contains measurements of the lengths of all internodes of all individuals.

This repository contains the files associated with the following article: Badano EI, FA Guerra-Coss, EJ Sánchez-Montes de Oca, CI Briones-Herrera & SM Gelviz-Gelvez. Climate change effects on early stages of Quercus ariifolia (Fagaceae), an endemic oak from seasonally dry forests of Mexico. Acta Botanica Mexicana, 126, Article e1466. https://doi.org/10.21829/abm126.2019.1466 The first Microsoft Excel file (Additional data 01 - Microclimate.xlsx) contains microclimate data gathered within control plots and climate change simulation plots (CCS plots) during the field experiment. These data include air temperature (measured every hour in 10 experimental units of each climate treatment with dataloggers - HOBO U23-Pro-V2, Onset Computer Corporation, USA), rainfall (measured at each rainfall event in 5 experimental units of each climate treatment with automatized pluviometers - HOBO S-RGB-M002, Onset Computer Corporation, USA) and soil water content (measured every week in 10 experimental units of each climate treatment with a time-domain reflectometer - FieldScout TDR 300, Spectrum Technologies, USA). Values of each of these variables are provided in different spreadsheets. The second Microsoft Excel file (Additional data 02 - Seedling responses) contains the data used to calculate the emergence rates and survival rates of Quercus ariaefolia during the experimental period a each experimental treatment. This file also contains the data gathered at the end of the experiment about chlorophyll content (in SPAD Units) and chlorophyll fluorescence (the spreadsheet contains the values of these variables measured on each seedling leaf; the computation of averages across leaves of each seedling is provided on the side), and the other functional traits measured on seedlings from controls and CCS plots. This work was supported by Project SEP-CONACYT CB-2013/221623 to EIB

Data uploaded corresponds to data collected from a flux tower installed at the basin mangrove located in Puerto Morelos (Jardín Botánico Dr. Alfredo Barrera Marín), Quintana Roo, Mexico. The collection pediod was from 13 June 2017 to 30 Nov 2018. Conventional procedures of the eddy covariance method (Burba, 2013) were followed to process raw flux data and produce half-hourly averaged data of net ecosystem-atmosphere CO2 flux (µmol s-1 m-2), latent heat flux (W m-2), and sensible heat flux (W m-2), using the software EddyPro 6.2.1 (LI-COR). Surface energy balance components are included (net radiation and its components, and soil heat flux). Ancillary data includes meteorological variables (air temperature and relative humidity, vapor pressure deficit, atmospheric pressure, precipitation, soil temperature, photosynthetically active radiation) as well as inundation water level and water temperature.

A reverse osmosis system driven by photovoltaic energy is an eco-friendly and sustainable way to produce freshwater in rural areas without connection to a power grid and with available brackish water sources. This paper describes a project where a photovoltaic-driven low-pressure reverse osmosis system (LPRO-PV) was designed, tested under laboratory conditions, and installed in Samalayuca, Chihuahua, Mexico, to evaluate the technical feasibility and social impact of this technology. The LPRO-PV system was tested with synthetic water with a salinity of 2921 ± 62.3 mg/L; the maximum freshwater volume produced was 1.8 ± 0.06 m3/day with a salinity value of 91 ± 1.9 mg/L. The LPRO-PV system satisfied the basic freshwater requirements for a local family of three members for one year, including the mobility-restriction period due to the COVID-19 pandemic. The social evaluation analysis reflects the importance of considering the technical aspects derived from the experimental tests, as well as the users’ perception of the performance and operation of the system. As a result of the implementation of this technology and the benefits described by the users, they committed to the maintenance activities required for the LPRO-PV system’s operation. This technology has great potential to produce fresh water in arid and isolated regions with high-salinity groundwater sources, thus fulfilling the human right to safe and clean drinking water.

Waste with high biomass content generated in cities in developing countries is sent to landfills or open dumps. This research aims to degrade biomass content in urban waste through cultivation, at pilot scale, of the edible mushroom Pleurotus ostreatus. First, the number of diapers used by one baby per week was measured with a survey in day care facilities. Then, cellulose content of diapers was assessed. Finally, cultivation of P. ostreatus was carried out using as substrate a mixture of diapers with gardening waste, a co-substrate readily available at urban settings. The factors assessed were strain of P. ostreatus (grey BPR-81, white BPR-5), conditioning of the substrate (diapers with and without plastic) and co-substrate (wheat straw, grass, and withered leaves). Results show that diapers are a valuable source of biomass, as generation of diapers with urine is 15.3 kg/child/month and they contain 50.2% by weight of cellulose. The highest reductions in dry weight and volume (>64%) of substrates was achieved with the substrate diaper without plastic and co-substrate wheat straw. Although diapers with plastic and grass and leaves showed lower degradation, they achieved efficiencies that make them suitable as a co-substrate (>40%), considering that their biomass is currently confined in landfills.