Social attributes and associated performance measures in marmots: bigger male bullies and weakly affiliating females have higher annual reproductive success

Studying the structure of social interactions is fundamental in behavioral ecology as social behavior often influences fitness and thus natural selection. However, social structure is often complex, and determining the most appropriate measures of variation in social behavior among individuals can be difficult. Social network analysis generates numerous, but often correlated, measures of individual connectedness derived from a network of interactions. We used measures of individual connectedness in networks of affiliative and agonistic interactions in yellow-bellied marmots, Marmota flaviventris, to first determine how variance was structured among network measures. Principal component analysis reduced our set of network measures to four “social attributes” (unweighted connectedness, affiliation strength, victimization, and bullying), which revealed differences between patterns of affiliative and agonistic interactions. We then used these extracted social attributes to examine the relationship between an individual’s social attributes and several performance measures: annual reproductive success, parasite infection, and basal stress. In male marmots, bullying was positively associated with annual reproductive success, while in females, affiliation strength was negatively associated with annual reproductive success. No other social attributes were significantly associated with any performance measures. Our study highlights the utility of considering multiple dimensions when measuring the structure and functional consequences of social behavior.     

A novel radiant floor system: Detailed characterization and comparison with traditional radiant systems

ABSTRACT

Radiant floor systems have the potential to reduce energy consumption and the carbon footprint of buildings. This study analyzed a novel radiant panel configuration comprising a metal plate with small spikes that can be pressed into cement board or wood. The behavior of this configuration was simulated for different materials for the metal plate, spike dimensions, and varying spacing between spikes. An annual energy simulation model compared the radiant panel configuration with the traditional concrete-based system. Simulations were run under heating dominant, cooling dominant, and neutral conditions; significant cost savings and greenhouse gas emission reduction were seen across all scenarios.     

Influences of chlorine content on emission of HCl and organic compounds in waste incineration using fluidized beds

HCl and some organic compounds are the precursors of polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) in municipal solid waste incinerators. In this work, a lab-scale fluidized bed incinerator is adopted to study the relationship between the organic and the inorganic chlorine contents of artificial wastes and the emissions of HCl and organic compounds. The lower threshold limit (LTL) of chlorine content below which HCl and organic compounds are not generated is studied. Experimental results showed that organic chlorides had a greater potential to release chlorine than inorganic chlorides. The generation of organic pollutants fell, but the emissions of HCl increased with the temperature. The concentrations of chlorophenols (CPs)/chlorobenzenes (CBs) increased with chlorine contents. No LTL existed for HCl regardless of whether CaO was added. The LTL for CPs was between 0.1 and 0.3wt% of inorganic chloride, but there was none for organic sources. For CBs, the LTL was between 0.5 and 1.0wt% for inorganics at 700 and 800 degrees C, but 0.1-0.3 wt% at 700 degrees C and 0.3-0.5 wt% at 800 degrees C for organics. The production of PAHs and benzene, toluene, ethylbenzene and xylene (BTEX) was related to the surplus hydrogen ions that were not reacted with the chlorine. Adding CaO inhibited the production of HCl, CBs and CPs, but did not seriously affect PAHs and BTEX.     

Catalytic oxidation of organic compounds in incineration flue gas by a commercial palladium catalyst

The object of this study is to investigate the effect of different operation conditions on the catalytic oxidation of trace organic compounds [i.e., benzene, toluene, ethylbenzene, and xylene (BTEX); and polyaromatic hydrocarbons (PAHs)] in incineration flue gas. A commercial Pd-based honeycomb catalyst, which is applied to treat flue gas with low organic concentrations and high gas velocity, is employed in this study. The investigated parameters include (1) effect of different space velocities, (2) effect of heavy metals, (3) effect of acid gas, and (4) effect of water vapor and ash particles. In this work, an effective catalyst oxidation system is constructed and expected to purify the incineration flue gas. Catalyst oxidation is a potential purification system that will meet the stricter regulations on the emissions of incineration systems. Experimental results showed that the destruction efficiency of PAHs and BTEX in Pd catalyst was generally greater than 80%. Decreasing the space velocity increased the decomposition efficiency of organic compounds. When the feedstock contained the heavy metals Pb and Cr, the oxidation of organic compounds was not inhibited. But the presence of Cd significantly decreased the oxidation efficiency. The acid gases SO2 and HCl in the flue gas could have influenced the crystal structure of PdO and subsequently deactivated/poisoned the Pd catalyst. The effect of water vapor on the catalytic destruction of PAHs and BTEX was not obvious.     

Relationship between pressure fluctuations and generation of organic pollutants with different particle size distributions in a fluidized bed incinerator

The hydrodynamic behaviors of fluidization perhaps significantly influence the uniformity of fluidization in fluidized bed incinerator. Good uniformity of fluidization expressed the air across uniformly through the bed and the particles being distributed well in the fluid stream. The aggregates, flocs and channels of particles do not happen during fluidization. The Good uniformity will maintain high heat and mass distribution to improve reaction efficiency. These parameters include the height of static bed, gas velocity, mixing and distribution of bed particle, which have rarely been studied in previous investigations. Consequently, this study examines how the hydrodynamic parameters affect the generation of organic pollutants (BTEXs and PAHs) during incineration. The statistical and power spectral analysis of the measured pressure fluctuation during incineration are used to elucidate the relationship between behaviors of fluidization and generation of pollutants during incineration. Experimental results show the organic concentration does not increase with uniformity of fluidization decreasing. The reason may be the explosion of the gas and the consequent thermal shock destroy the coalescent bubbles to form small bubbles again and enhance the efficiency of transfer of oxygen to increase combustion efficiency. Additionally, the mean amplitude and fluidized index of pressure fluctuation similarly vary with the concentration of organic pollutants. These two indices can be used to assess the efficiency of combustion. The four particle size distributions could be divided into two groups by statistical analysis. The Gaussian and narrow distributions belong to one group and the binary and flat the other. The organic concentration of the Gaussian and narrow distributions are lower than that of the other distributions. Consequently, the bed materials should maintain narrow or Gaussian distributions to maintain a good combustion efficiency during incineration.     

Refuse-derived fuel as a secondary energy in Taiwan—Using Hotelling space allocation model

Most Taiwanese farmers usually blend rice straws into the soil after harvest. However, rice straws possess great thermal energy, which can be used to produce refuse-derived fuel (RDF-5). As Taiwan faces energy shortage, the development benefits of the RDF-5 industry are tempting. This study employs the Hotelling model to design the locations and the optimal numbers of RDF-5 plants. From the technology and material supply point of view, turning waste rice straws into RDF-5 is feasible in Taiwan. Nevertheless, from the business operation perspective, even if the RDF-5 plant is willing to lower its profit rate, its selling price is still hard to compete with imported RDF-5. If the Taiwanese government decides to pursue RDF-5 as an alternative energy, they might need to take a step further to subsidize entrepreneurs or provide appropriate tax benefits. Otherwise, the RDF-5 industry is hard to survive in Taiwan.     

The effect of operating conditions on the capture of metals with limestone during incineration

The objective of this work was to experimentally study the effect of different operating conditions on sorbent (limestone) to capture metals and the formation of hexavalent chromium during fluidized bed incineration of wastes containing Pb, Cd, Cu, and Cr. The operating parameters evaluated included: 1) addition of organic chloride (PVC); 2) addition of inorganic chloride (NaCl); 3) addition of sulfide (Na₂S); 4) size of sorbent; and, 5) air factor. The experiments were carried out in a pilot scale fluidized bed incinerator with air pollution control devices of two consecutive cyclones and a wet scrubber. Experimental results indicated that limestone could effectively capture most heavy metals Pb, Cr, and Cd in the sand bed. The addition of organic chloride (PVC) and inorganic chloride (NaCl) in feedstock caused different consequences. The former decreased the adsorption efficiency, while the latter increased the adsorption efficiency of limestone in the sand bed. Moreover, the presence of sulfide (Na₂S) was helpful in controlling metals during incineration. Little hexavalent chromium is formed during incineration, but the presence of organic chloride PVC produced more Cr(VI) than inorganic chloride NaCl.     

Influence of Operating Conditions on the Formation of Heavy Metal Compounds During Incineration

ABSTRACT

The formation of Cr, Pb, and Cd species under various operating conditions in a pilot-scale fluidized-bed incinerator was investigated. Examined were the effects of (1) an organic chloride (PVC) additive, (2) an inorganic chloride (NaCl) additive, and (3) NaNO₃ and PVC additives,

under various operating temperatures. Two-stage modeling was performed to match the actual incineration conditions of the current study.

Thermodynamic equilibrium analysis indicated that Cr₂O₃, PbCl₂, and CdCl₂ were the dominant species of Cr, Pb, and Cd when an organic chloride (PVC) was present, whereas PbO and CdO were the dominant species under the other operating conditions. The XRD analysis identified Cr₂O₃, PbCl₂, and CdCl₂»H₂O as the dominant species of Cr, Pb, and Cd when an organic chloride (PVC) was present, whereas Cr₂O₃, PbO, Pb₂O₃, CdO, and CdCO₃ were identified under the other operating conditions. The sodium contained in the feedstock was shown to react with chlorine to form sodium chloride both in modeling results and by X-ray diffraction (XRD) analysis. The temperature of the operating conditions had little effect on the formation of heavy metal species.     

Pore Structure Effects on Ca-Based Sorbent Sulfation Capacity at Medium Temperatures: Activated Carbon as Sorbent/Catalyst Support

Abstract

The reaction between three different Ca-based sorbents and SO₂ were studied in a medium temperature range (473–773 K). The largest SO₂ capture was found with Ca(OH)₂ at 773 K, 126.31 mg SO₂?g Ca(OH)₂ ^?1, and the influence of SO₂ concentration on the sorbent utilization was observed. Investigations of the internal porous structure of Ca-based sorbents showed that the initial reaction rate was controlled by the surface area, and once the sul-fated products were produced, pore structure dominated. To increase the surface area of Ca-based sorbents available to interact with and retain SO₂, one kind of CaO/activated carbon (AC) sorbent/catalyst was prepared to study the effect of AC on the dispersion of Ca-based materials. The results indicated that the Ca-based material dispersed on high-surface-area AC had more capacities for SO₂ than unsupported Ca-based sorbents. The initial reaction rates of the reaction between SO₂ and Ca-based sorbents and the prepared CaO/AC sorbents/cata-lysts were measured. Results showed that the reaction rate apparently increased with the presence of AC. It was concluded that CaO/AC was the active material in the des-ulfurization reaction. AC acting as the support can play a role to supply O₂ to increase the affinity to SO₂. Moreover, when AC is acting as a support, the surface oxygen functional group formed on the surface of AC can serve as a new site for SO₂ adsorption.