Use of principal component analysis to evaluate thermal properties and combustibility of coffee-pine wood briquettes

Submitted: February 1st, 2021 ; Accepted: March 30th, 2021 ; Published: May 21st, 2021 ; Correspondence: [email protected] coffee production chain is a potential source of residual biomass inherent to the high productivity that can contribute to the generation of value-added products. The residues from the coffee sector are typically disposed to landfill without treatment causing potential environmental inconveniences. Briquetting presents an alternative process to produce a uniform fuel with high energy density. Briquettes facilitates easy transportation, enables better handling and storage of biomass residues. Properties such as low equilibrium moisture content, high energy density and compressive strength were reported for different coffee-pine wood briquettes treatments. Moreover, understanding of the thermal properties of the briquettes during combustion is crucial to evaluate their final application. This research is the first study that investigates the combustibility properties and kinetic parameters of the thermal decomposition of briquettes from coffee-pine wood using differential and integral thermal analysis under non-isothermal conditions. Multivariate analysis of the collected parameters through principal components analysis (PCA), was implemented to reduce the dimensionality of the data. The desired profile in the combustibility is directly related to high temperatures and long burning times, thus, the tested briquettes displayed a significant combustibility potential, reporting peak temperatures and burnout times around 600 °C and 27 minutes, respectively. Activation energy kinetic parameter in the range of 12–42 kJ mol-1 and average reactivity of 0.14–0.22 min-1 , were also found. The results revealed the not thermally hard material to degrade when compared to biomasses typically used for combustion

Synthesis and design of suspended substrate stripline filters for digital microwave power amplifiers

In this paper, a synthesis method for suspended substrate stripline filters for digital microwave power amplifier applications is presented. The synthesis method combines a lumped element and full-wave mixed approach in a very efficient way. In order to achieve high amplifier efficiency the filter must exhibit a high input impedance in the stopband. This has been implemented for the first time by using a capacitively end coupled filter combined with stepped impedance resonators. A third order filter was designed. Simulations show that the final stage drain efficiency of the power amplifier and suppression of out-of-band frequency components can be significantly improved when the new structure is used

Genetic and Molecular Characterization of Temperate and Tropical Forage Maize Inbred Lines

The livestock feeding in the Central highland of Mexico is based on harvest, grazing and annual forage conservation, being forage maize the most important silage crop (Alarcón, 1995). Even though forage maize is extensively bred in Europe, USA and Asia since 1900\u27s, this started in Mexico in the 1960\u27s, and little is known about the genetic diversity in both agronomic and nutritive value traits. Our breeding program goals are to analyze combining ability of biomass and quality predictors and to study the genetic relationship of inbred lines between lowland tropical and temperate races from Mesa Central, by genetic and molecular approaches

Genetic and Molecular Characterization of Temperate and Tropical Forage Maize Inbred Lines

Livestock feeding in the Central highland of Mexico is based on harvest, grazing and annual forage conservation, with forage maize being the most important silage crop (Alarcón, 1995). Even though forage maize is extensively bred in Europe, USA and Asia since the 1900’s, this started in Mexico only in the 1960’s, and little is known about genetic diversity in both agronomic and nutritive value traits. Our breeding program goals are to analyze combining ability of biomass and quality predictors and to study the genetic relationship of inbred lines between lowland tropical and temperate races from Mesa Central, by genetic and molecular approaches

Seasonal water storage and release dynamics of bofedal wetlands in the Central Andes

Tropical high-Andean wetlands, locally known as ‘bofedales’, are key ecosystems sustaining biodiversity, carbon sequestration, water provision and livestock farming. Bofedales' contribution to dry season baseflows and sustaining water quality is crucial for downstream water security. The sensitivity of bofedales to climatic and anthropogenic disturbances is therefore of growing concern for watershed management. This study aims to understand seasonal water storage and release characteristics of bofedales by combining remote sensing analysis and ground-based monitoring for the wet and dry seasons of late 2019 to early 2021, using the glacierised Vilcanota-Urubamba basin (Southern Peru) as a case study. A network of five ultrasound loggers was installed to obtain discharge and water table data from bofedal sites across two headwater catchments. The seasonal extent of bofedales was mapped by applying a supervised machine learning model using Random Forest on imagery from Sentinel-2 and NASADEM. We identified high seasonal variability in bofedal area with a total of 3.5% and 10.6% of each catchment area, respectively, at the end of the dry season (2020), which increased to 15.1% and 16.9%, respectively, at the end of the following wet season (2021). The hydrological observations and bofedal maps were combined into a hydrological conceptual model to estimate the storage and release characteristics of the bofedales, and their contribution to runoff at the catchment scale. Estimated lag times between 1 and 32 days indicate a prolonged bofedal flow contribution throughout the dry season (about 74% of total flow). Thus, our results suggest that bofedales provide substantial contribution to dry season baseflow, water flow regulation and storage. These findings highlight the importance of including bofedales in local water management strategies and adaptation interventions including nature-based solutions that seek to support long-term water security in seasonally dry and rapidly changing Andean catchments

Human Pleural Fluid Elicits Pyruvate and Phenylalanine Metabolism in Acinetobacter baumannii to Enhance Cytotoxicity and Immune Evasion

The CCAAT box-harboring proteins represent a family of heterotrimeric transcription factors which is highly conserved in eukaryotes. In fungi, one of the particularly important homologs of this family is the Hap complex that separates the DNA-binding domain from the activation domain and imposes essential impacts on regulation of a wide range of cellular functions. So far, a comprehensive summary of this complex has been described in filamentous fungi but not in the yeast. In this review, we summarize a number of studies related to the structure and assembly mode of the Hap complex in a list of representative yeasts. Furthermore, we emphasize recent advances in understanding the regulatory functions of this complex, with a special focus on its role in regulating respiration, production of reactive oxygen species (ROS) and iron homeostasis.Fil: Nyah, Rodman. California State University; Estados UnidosFil: Martinez, Jasmine. California State University; Estados UnidosFil: Fung, Sammie. California State University; Estados UnidosFil: Nakanouchi, Jun. California State University; Estados UnidosFil: Myers, Amber L.. California State University; Estados UnidosFil: Harris, Caitlin M.. California State University; Estados UnidosFil: Dang, Emily. California State University; Estados UnidosFil: Fernandez, Jennifer. California State University; Estados UnidosFil: Liu, Christine. California State University; Estados UnidosFil: Mendoza, Anthony M.. California State University; Estados UnidosFil: Jimenez, Verónica. California State University; Estados UnidosFil: Nikolaidis, Nikolas. California State University; Estados UnidosFil: Brennan, Catherine A.. California State University; Estados UnidosFil: Bonomo, Robert A.. Louis Stokes Cleveland Department of Veterans Affairs Medical Cente; Estados Unidos. Center for Antimicrobial Resistance and Epidemiology; Estados Unidos. Case Western Reserve University School of Medicine; Estados UnidosFil: Sieira, Rodrigo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Ramirez, Maria Soledad. California State University; Estados Unido

Validation of models with constant bias: an applied approach

Objective. This paper presents extensions to the statistical validation method based on the procedure of Freese when a model shows constant bias (CB) in its predictions and illustrate the method with data from a new mechanistic model that predict weight gain in cattle. Materials and methods. The extensions were the hypothesis tests and maximum anticipated error for the alternative approach, and the confidence interval for a quantile of the distribution of errors. Results. The model evaluated showed CB, once the CB is removed and with a confidence level of 95%, the magnitude of the error does not exceed 0.575 kg. Therefore, the validated model can be used to predict the daily weight gain of cattle, although it will require an adjustment in its structure based on the presence of CB to increase the accuracy of its forecasts. Conclusions. The confidence interval for the 1-α quantile of the distribution of errors after correcting the constant bias, allows determining the top limit for the magnitude of the error of prediction and use it to evaluate the evolution of the model in the forecasting of the system. The confidence interval approach to validate a model is more informative than the hypothesis tests for the same purpose