Microanalysis of Primary Biological Particles from Model Grass over Its Life Cycle

Abstract

This review examines the detailed chemical insights that have been generated through 150 years of work worldwide on magnesium-based inorganic cements, with a focus on both scientific and patent literature. Magnesium carbonate, phosphate, silicate-hydrate, and oxysalt (both chloride and sulfate) cements are all assessed. Many such cements are ideally suited to specialist applications in precast construction, road repair, and other fields including nuclear waste immobilization. The majority of MgO-based cements are more costly to produce than Portland cement because of the relatively high cost of reactive sources of MgO and do not have a sufficiently high internal pH to passivate mild steel reinforcing bars. This precludes MgO-based cements from providing a large-scale replacement for Portland cement in the production of steel-reinforced concretes for civil engineering applications, despite the potential for CO 2 emissions reductions offered by some such systems. Nonetheless, in uses that do not require steel reinforcement, and in locations where the MgO can be sourced at a competitive price, a detailed understanding of these systems enables their specification, design, and selection as advanced engineering materials with a strongly defined chemical basis. CONTENTS 1. Introduction 4170 1.1. Cements Based on MgO 4171 1.2. Magnesia Production 4171 2. Magnesium Carbonate and Reactive Magnesia Cements 4173 2.1. Reactive Magnesia 4173 2.2. Expansive MgO Cements 4173 2.3. Development of Reactive Magnesia Cements 4174 2.4. Carbonated Magnesia (MgO) Blocks 4176 2.5. Novacem 4177 2.6. Limitations of Carbon Sequestration 4177 2.7. Conclusions 4178 3. Magnesium Phosphate Cements 4178 3.1. Phosphate Bonding of MgO 4178 3.2. Application as Cements 4179 3.3. Method of Action 4179 3.4.

Chemical Imaging of Fine Mode Atmospheric Particles Collected from a Research Aircraft over Agricultural Fields

“…20 Studies have found a rise in accumulation mode particles during plant growth with approximately 60% of emitted particles attributed to PBAPs. 33 This suggests a correlation between the plant's life cycle and PBAP emissions. A unique property of PBAPs is that some of them (e.g., pollen and fungal spore) tend to disintegrate by releasing fine fragments through multiple mechanisms.…”

“…via oxidative modifications . Studies have found a rise in accumulation mode particles during plant growth with approximately 60% of emitted particles attributed to PBAPs . This suggests a correlation between the plant’s life cycle and PBAP emissions.…”

Chemical Interactions in the Plant–Atmosphere–Soil System

“…Three papers deal with atmospheric emissions of PBAPs from such diverse systems as the model grass Brachypodium distachyon (China et al), 1 agricultural corn and soybean fields (Tomlin et al), 2 and tree pollen (Rivas-Ubach et al). 3 China et al 1 reveal that compositional characteristics and types of emitted biological particles are highly variable at the different growth stages of B. distachyon. Tomlin et al 2 find that particle classes are consistent between corn and soybean harvesting periods and emphasize that seasonal harvesting of crops may play an important role in regional atmospheric dynamics.…”

“…Primary biological aerosol particles (PBAPs) are directly released from diverse systems of the biosphere into the atmosphere, while secondary organic aerosol (SOA) formation occurs through oxidation of biogenic volatile organic compound (BVOC) emissions. Three papers deal with atmospheric emissions of PBAPs from such diverse systems as the model grass Brachypodium distachyon (China et al), agricultural corn and soybean fields (Tomlin et al), and tree pollen (Rivas-Ubach et al) . China et al reveal that compositional characteristics and types of emitted biological particles are highly variable at the different growth stages of B.…”

“…Three papers deal with atmospheric emissions of PBAPs from such diverse systems as the model grass Brachypodium distachyon (China et al), agricultural corn and soybean fields (Tomlin et al), and tree pollen (Rivas-Ubach et al) . China et al reveal that compositional characteristics and types of emitted biological particles are highly variable at the different growth stages of B. distachyon.…”