The rate of decomposition of hydrogen peroxide has been measured in aqueous, concentrated (0.1–1M) reagent-grade sodium carbonate liquors and compared with that in sodium hydroxide liquors at the same pH, temperature, and ionic strength. Over the ranges of temperature (303–323 K), pH (10.0–10.6), and ionic strength (1.5–3.0M), and without peroxide-stabilizing additives, hydrogen peroxide decomp...

The Eocene-Oligocene transition (EOT), ~34Ma, marks a tipping point in the long-term Cenozoic greenhouse to icehouse climate transition. Paleorecords reveal stepwise rapid cooling and ice growth across the EOT tightly coupled to a transient benthic δC excursion and a major and permanent deepening of the carbonate compensation depth (CCD). Based on biogeochemical box modeling, Merico et al. (200...

Analysis of 171 samples taken from the Neogene cohesive soils of the Southeastern edge of the Granada basin shows inverse correlation between carbonate content and dispersion index and swelling behaviour and direct correlations between carbonate content and shear strength. This paper shows that carbonate content and clay fraction activity have a great influence on the compaction characteristics...

In this study, we developed a metal-free biosynthetic strategy of enzymatic polymerization to fabricate aliphatic poly(pentamethylene carbonate) (PPMC). Novozym-435 lipase showed considerably high catalytic efficiency, and high molecular weights (Mn) of up to 6.0 104 g mol 1 were readily achieved through the ring-opening polymerization of cyclobis(pentamethylene carbonate). The reaction paramet...

Calcium carbonate is an abundant substance that can be created in several mineral forms by the reaction of dissolved carbon dioxide in water with calcium ions. Through biomineralization, organisms can harness and control this process to form various functional materials that can act as anything from shells through to lenses. The early stages of calcium carbonate formation have recently attracte...

Calcium carbonate forms scales, geological deposits, biominerals, and ocean sediments. Huge amounts of carbon dioxide are retained as carbonate ions, and calcium ions represent a major contribution to water hardness. Despite its relevance, little is known about the precipitation mechanism of calcium carbonate, and specified complex crystal structures challenge the classical view on nucleation c...

In the present investigation, the oxidizing roasting process of chromite with sodium carbonate to prepare potassium dichromate crystals was studied in the microwave field with air, by heating the chromite and sodium carbonate. The chromite and sodium carbonate heated separately at 1000 ◦C in the microwave oven (frequency: 2.45 GHz; power 1.5 kW) in order to study the microwave absorption proper...

A series of experiments was performed to evaluate the effect of substituting sodium carbonate for the sodium hydroxide used in peroxide bleaching of spruce CTMP. Three peroxide levels were tested: I , 2, and 4% HzOz, and two levels of causticsubstitution; SO% and 80%. At both the 2% and 4% peroxide levels, substituting 50% of the caustic charge with sodium carbonate decreased the initial bright...

As models of the composition and heterogeneous chemical reactions of the troposphere undergo refinement, novel application of state-of-the-art analytical techniques will be necessary to propound realistic characterizations of mineral dust chemistry. In this study, strontium carbonate particles treated with gaseous nitric acid and nitrogen dioxide were examined with X-ray absorption fine structu...

In this study, we report the synthesis and characterisation of a thermogelling poly(carbonate urethane) system comprising poly(ethylene glycol) (PEG), poly(propylene glycol) (PPG) and poly(polytetrahydrofuran carbonate) (PTHF carbonate). The incorporation of PTHF carbonate allowed for the control of the lower critical solution temperature (LCST) and decreased critical gelation concentration (CG...