Microwave heating processing as alternative of pretreatment in second-generation biorefinery: An overview

The development of a feasible biorefinery is in need of alternative technologies to improve lignocellulosic biomass conversion by the suitable use of energy. Microwave heating processing (MHP) is emerging as promising unconventional pretreatment of lignocellulosic materials (LCMs). MHP applied as pretreatment induces LCMs breakdown through the molecular collision caused by the dielectric polarization. Polar particles movement generates a quick heating consequently the temperatures and times of process are lower. In this way, MHP has positioned as green technology in comparison with other types of heating. Microwave technology represents an excellent option to obtain susceptible substrates to enzymatic saccharification and subsequently in the production of bioethanol and high-added compounds. However, it is still necessary to study the dielectric properties of materials, and conduct economic studies to achieve development in pilot and industrial scale. This work aims to provide an overview of recent progress and alternative configurations for combining the application of microwave technology on the pretreatment of LCMs in terms of biorefinery.Financial support is gratefully acknowledged from the Energy Sustainability Fund 2014-05 (CONACYT-SENER), Mexican Centre for Innovation in Bioenergy (Cemie-Bio), Cluster of Bioalcohols (Ref. 249564). This study was supported by the Secretary of Public Education of Mexico PROMEP project/103.5/13/6595 – UACOAH-PTC-292 and PROMEP project/DSA/103.5/14/10442 – UACOAH-PTC-312. We gratefully acknowledge support for this research by the Mexican Science and Technology Council (CONACYT, Mexico) for the infrastructure project - INFR201601 (Ref. 269461) and CB-2015-01 (Ref. 254808). The author A. Aguilar-Reynosa thanks to Mexican Science and Technology Council (CONACY, Mexico) for master fellowship support

Migration, Ethnicity and Economic Integration

This chapter deals with the economic and ethnic diversity caused by international labor migration, and their economic integration possibilities. It brings together three strands of literature dealing with the neoclassical economic assimilation, ethnic identities and attitudes towards immigrants and the natives, and provides an analysis in understanding their interactions. The issue of how immigrants fare in the host country especially in terms of their labor force participation and remuneration has been the core of research in the labor migration literature. If immigrants fare as well as the natives, then they are economically assimilated. While some immigrant groups do, most do not, especially in Europe. Of equal importance is how immigrants identify with the culture of their home and receiving countries, and if natives and immigrants have the right attitudes about each other. Ethnic identities and attitudes seem to be less affected by the economic environment but have implications for economic performance

Comparison of microwave and conduction-convection heating autohydrolysis pretreatment for bioethanol production

This work describes the application of two forms of heating for autohydrolysis pretreatment on isothermal regimen: conduction-convection heating and microwave heating processing using corn stover as raw material for bioethanol production. Pretreatments were performed using different operational conditions: residence time (10-50 minutes) and temperature (160-200°C) for both pretreatments. Subsequently, the susceptibility of pretreated solids was studied using low enzyme loads, and high substrate loads. The highest conversion was 95.1% for microwave pretreated solids. Also solids pretreated by microwave heating processing showed better ethanol conversion in simultaneous saccharification and fermentation process (92% corresponding to 33.8 g/L). Therefore, microwave heating processing is a promising technology in the pretreatment of lignocellulosic materials.Financial support from the Energy Sustainability Fund 2014-05 (CONACYT-SENER), Mexican Centre for Innovation in Bioenergy (Cemie-Bio), Cluster of Bioalcohols (Ref. 249564) is gratefully acknowledged. We also gratefully acknowledge support for this research by the Mexican Science and Technology Council (CONACYT, Mexico) for the Infrastructure Project - INFR201601 (Ref. 269461) and Ciencia Basica-2015-01 (Ref. 254808). This study also was supported by the Secretary of Public Education of Mexico: PROMEP project/103.5/13/6595. The author Alejandra Aguilar also thanks the National Council for Science and Technology (CONACYT, Mexico) for Master fellowship support (grant number: 559391/296768).info:eu-repo/semantics/publishedVersio

Severity factor kinetic model as a strategic parameter of hydrothermal processing (steam explosion and liquid hot water) for biomass fractionation under biorefinery concept

Hydrothermal processes are an attractive clean technology and cost-effective engineering platform for biorefineries based in the conversion of biomass to biofuels and high-value bioproducts under the basis of sustainability and circular bioeconomy. The deep and detailed knowledge of the structural changes by the severity of biomasses hydrothermal fractionation is scientifically and technological needed in order to improve processes effectiveness, reactors designs, and industrial application of the multi-scale target compounds obtained by steam explosion and liquid hot water systems. The concept of the severity factor [log10 (Ro)] established>30 years ago, continues to be a useful index that can provide a simple descriptor of the relationship between the operational conditions for biomass fractionation in second generation of biorefineries. This review develops a deep explanation of the hydrothermal severity factor based in lignocellulosic biomass fractionation with emphasis in research advances, pretreatment operations and the applications of severity factor kinetic model

Caregiver Well-Being and Burden: Variations by Race/Ethnicity and Care Recipient Nativity Status

Background and Objectives: Despite growing diversity among the aging population and extensive previous research on racial/ethnic minority caregivers, little research has been conducted on the potentially unique experiences and outcomes of informal caregivers of foreign-born care recipients. Using nationally representative data and the Stress Process Model, the current study examined the differences in caregiver outcomes (care burden, psychological well-being, and self-rated health) by care recipient nativity status (U.S.-born vs. foreign-born) and the extent to which caregiver outcomes vary by care recipient nativity status and caregiver race/ethnicity (non-Hispanic white, non-Hispanic black, Hispanic, and Others). Research Design and Methods: The current study used Round 5 of the National Health and Aging Trends Study and the National Study of Caregiving (N = 1,436). We conducted ordinary least squares regression to analyze the differences in caregiver’s outcomes by care recipient nativity status and caregiver race/ethnicity and to investigate the impacts of the inclusion of caregiving factors (background factors, primary stressors, secondary stressors, and resources). Results: Regression analyses showed that only care burden significantly varied by care recipient nativity status after controlling for covariates. Caregivers of foreign-born care recipients reported a higher burden. However, when interactions of care recipient nativity status × caregiver race/ethnicity were introduced, non-Hispanic black and Hispanic caregivers of foreign-born care recipients were more likely to report better psychological well-being and self-rated health compared to their counterparts. Across caregiver groups, better caregiver–care recipient relationship quality and less caregiver chronic conditions were associated with less burden and better caregiver psychological well-being and self-rated health. Discussion and Implications: Care recipient nativity status and caregiver race/ethnicity may have complex effects on caregiving experiences. Given the observed significant interaction effects for caregiver psychological well-being and self-rated health, cultural factors may affect the extent to which these caregivers appraise their caregiving. Future research should delve into the appropriate ways to assess care stress as well as resilience among each caregiver group. Our results indicate the need for research, education, and practice that assess cultural and within-group differences among caregivers and inform needed changes to structural barriers