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1,2,4-Trioxolanes, known as secondary ozonides (SOZs), are key products of ozonolysis of biogenic terpenoids. Functionalized terpenoid-derived SOZs are readily taken up into atmospheric aerosols; however, their condensed-phase fates remain unknown. Here, we report the results of a time-dependent mass spectrometric investigation into the liquid-phase fates of C

Carbon (C), nitrogen (N), and phosphorus (P) stoichiometry and their allometric relationships in soil and plants are hot topics that attract a lot of attention, while those rocks that form soils are often neglected. Weathering is a common geological phenomenon that may significantly influence the nutrient composition and release of nutrients from rock and its inherent soils. This study presents C, N, and P concentrations data as well as microscope petrological photographs of fresh and weathered sandstones from Longhushan World Geopark in SE China, in an attempt to investigate C, N, and P stoichiometry of rocks before and after weathering and discuss the driving mechanisms. The results show that weathering significantly decreased rock C, C/N, and C/P concentrations, slightly decreased N and N/P concentrations, and slightly increased P concentration. Microscope observations show that fresh sandstones contain calcite, apatite, microplagioclase, and organic matter, while weathered sandstones feature apatite and organic matter. The flexible allometric relationships and mineral changes before and after rock weathering indicate that chemical mechanisms, such as dissolution of carbonate and hydration of microplagioclase, have changed the existence form of C, N, P and, thus, significantly influence rock C, N, and P stoichiometry. This stoichiometry feature can be in turn used to reflect the regulation effect of rock weathering.

Organic hydroperoxides (ROOHs) play key roles in the atmosphere as a reactive intermediate species. Due to the low volatility and high hydrophilicity, ROOHs are expected to reside in atmospheric condensed phases such as aerosols, fogs, and cloud droplets. The decomposition mechanisms of ROOHs in the liquid phase are, however, still poorly understood. Here we report a temperature-dependent kinetics and theoretical calculation study of the aqueous-phase decompositions of C

In the atmosphere, most biogenic terpenes undergo ozonolysis in the presence of water to form reactive α-hydroxyalkyl-hydroperoxides (α-HHs), and the lifetimes of these α-HHs are a key parameter for understanding the processes that occur during the aging of atmospheric particles. We previously reported that α-HHs generated by ozonolysis of terpenes decompose in water to give H2O2 and the corresponding aldehydes, which undergo hydration to form gem-diols. Herein, we report that this decomposition process was dramatically accelerated by acidification of the water with oxalic, acetic, hexanoic, cis-pinonic, or hydrochloric acid. In acidic solution, the temporal profiles of the α-HHs, detected as their chloride adducts by electrospray mass spectrometry, showed single-exponential decays in the pH range from 4.1 to 6.1, and the first-order rate coefficients (k) for the decays increased with decreasing pH. The lifetime of the α-HH derived from α-terpineol was 128 min (k = (1.3 ± 0.4) × 10-4 s-1) at pH 6.1 but only 8 min (k = (2.1 ± 0.1) × 10-3 s-1) at pH 4.1. Because the rate coefficients increased as the pH decreased and the increase depended on pH rather than on the properties of the acid, we propose that the decomposition of the α-HHs in water was specifically catalyzed by H+. Fast H+-catalyzed decomposition of α-HHs could be an important source of H2O2 and multifunctionalized compounds found in ambient atmospheric particles.

Acidity changes the physical properties of atmospheric aerosol particles and the mechanisms of reactions that occur therein and on the surface. Here, we used surface-sensitive pneumatic ionization mass spectrometry to investigate the effects of pH on the heterogeneous reactions of aqueous α-terpineol (C10H17OH), a representative monoterpene alcohol, with gaseous ozone. Rapid (≤10 μs) ozonolysis of α-terpineol produced Criegee intermediates (CIs, zwitterionic/diradical carbonyl oxides) on the surface of water microjets. We studied the effects of microjet bulk pH (1-11) on the formation of functionalized carboxylate and α-hydroxy-hydroperoxide chloride adduct (HH-Cl-) products generated by isomerization and hydration of α-terpineol CIs, respectively. Compared with the signal at pH ≈ 6, the mass spectral signal of HH-Cl- was less intense under both basic and more acidic conditions, whereas the intensity of the functionalized carboxylate signal increased with increasing pH up to 4 and then remained constant. The decrease of HH-Cl- signals at bulk pH values of >6 is attributable to the accumulation of OH- at the air-water interface that suppresses the relative abundance of hydrophilic HH and Cl-. The present study suggests that α-terpineol in ambient aqueous organic aerosols will be converted into much lower volatile and potentially toxic organic hydroperoxides during the heterogeneous ozonolysis.

Ozone readily reacts with olefins with the formation of more reactive Criegee intermediates (CIs). The transient CIs impact HOx cycles, and they play a role in new particle formation in the troposp...

In the atmosphere, carbonyl oxides known as Criegee intermediates are produced mainly by ozonolysis of volatile organic compounds containing C[double bond, length as m-dash]C double bonds, such as biogenic terpenoids. Criegee intermediates can react with OH-containing species to produce labile organic hydroperoxides (ROOHs) that are taken up into atmospheric condensed phases. Besides water, alcohols are an important reaction partner of Criegee intermediates and can convert them into α-alkoxyalkyl-hydroperoxides (α-AHs), R1R2C(-OOH)(-OR'). Here, we report a study on the aqueous-phase fates of α-AHs derived from ozonolysis of α-terpineol in the presence of methanol, ethanol, 1-propanol, and 2-propanol. The α-terpineol α-AHs and the decomposition products were detected as their chloride adducts by electrospray mass spectrometry as a function of reaction time. Our discovery that the rate of decomposition of α-AHs increased as the pH decreased from 5.9 to 3.8 implied that the decomposition mechanism was catalyzed by H+. The use of isotope solvent experiments revealed that a primary decomposition product of α-AHs in an acidic aqueous solution was a hemiacetal R1R2C(-OH)(-OR') species that was further transformed into other products such as lactols. The proposed H+-catalyzed decomposition of α-AHs, which provides H2O2 and multifunctional species in ambient aerosol particles, may be faster than other degradation processes (e.g., photolysis by solar radiation).

Ozonolysis of unsaturated organic species with water produces α-hydroxyalkyl-hydroperoxides (α-HHs), which are reactive intermediates that lead to the formation of H2O2 and multifunctionalized species in atmospheric condensed phases. Here, we report temperature-dependent rate coefficients (k) for the aqueous-phase decomposition of α-terpineol α-HHs at 283-318 K and terpinen-4-ol α-HHs at 313-328 K. The temporal profiles of α-HH signals, detected as chloride adducts by negative-ion electrospray mass spectrometry, showed single-exponential decay, and the derived first-order k for α-HH decomposition increased as temperature increased, e.g., k(288 K) = (4.7 ± 0.2) × 10-5, k(298 K) = (1.5 ± 0.4) × 10-4, k(308 K) = (3.4 ± 0.9) × 10-4, k(318 K) = (1.0 ± 0.2) × 10-3 s-1 for α-terpineol α-HHs at pH 6.1. Arrhenius plot analysis yielded activation energies of 17.9 ± 0.7 (pH 6.1) and 17.1 ± 0.2 kcal mol-1 (pH 6.2) for the decomposition of α-terpineol and terpinen-4-ol α-HHs, respectively. Activation energies of 18.6 ± 0.2 and 19.2 ± 0.5 kcal mol-1 were also obtained for the decomposition of α-terpineol α-HHs in acidified water at pH 5.3 and 4.5, respectively. Theoretical kinetic and thermodynamic calculations confirmed that both water-catalyzed and proton-catalyzed mechanisms play important roles in the decomposition of these α-HHs. The relatively strong temperature dependence of k suggests that the lifetime of these α-HHs in aqueous phases (e.g., aqueous aerosols, fog, cloud droplets, wet films) is controlled not only by the water content and pH but also by the temperature of these media.

The α-hydroxyalkyl-hydroperoxides [R–(H)C(−OH)(−OOH), α-HH] produced in the ozonolysis of unsaturated organic compounds may contribute to secondary organic aerosol (SOA) aging. α-HHs’ inherent instability, however, hampers their detection and a positive assessment of their actual role. Here we report, for the first time, the rates and products of the decomposition of the α-HHs generated in the ozonolysis of atmospherically important monoterpenes α-pinene (α-P), d-limonene (d-L), γ-terpinene (γ-Tn), and α-terpineol (α-Tp) in water/acetonitrile (W/AN) mixtures. We detect α-HHs and multifunctional decomposition products as chloride adducts by online electrospray ionization mass spectrometry. Experiments involving D₂O and H₂¹⁸O, instead of H₂¹⁶O, and an OH-radical scavenger show that α-HHs decompose into gem-diols + H₂O₂ rather than free radicals. α-HHs decay mono- or biexponentially depending on molecular structure and solvent composition. e-Fold times, τ_(1/e), in water-rich solvent mixtures range from τ_(1/e) = 15–45 min for monoterpene-derived α-HHs to τ_(1/e) > 10³ min for the α-Tp-derived α-HH. All τ_(1/e)’s dramatically increase in

Secondary organic aerosol (SOA) found in polluted mega-cities contains benzoic acid (BA) as a major organic acid in addition to a variety of species including alkenes. In polluted air, ozone could be a major oxidizer for SOA and induces subsequent reactions involving Criegee intermediates (CIs, carbonyl oxide, RR′C•–O–O•/RR′C═O+–O–) formed by the −C═C– + O3 reaction at the gas/liquid interface. The possibility that abundant BA could be an effective scavenger of CIs at the interface remains to be investigated by direct experiments. Here, we showed that amphiphilic BA is able to compete with water molecules for the CIs produced in the prompt ozonolysis of β-caryophyllene on the surface of a water/acetonitrile solvent microjet by generating hitherto uncharacterized C22 ester hydroperoxide products. Competition between BA vs octanoic acid vs cis-pinonic acid toward CIs reveals that BA is a much less-efficient scavenger of CIs on aqueous organic surfaces. We attribute it to the surface-specific orientation of ...

Biogenic monoterpenes are major sources of Criegee intermediates (CIs) in the troposphere. Recent studies underscored the importance of their heterogeneous chemistry. The study of monoterpene CI reactions on liquid surfaces, however, is challenging due to the lack of suitable probes. Here, we report the first mass spectrometric detection of the intermediates and products, which include labile hydroperoxides, from reactions of CIs of representative monoterpenes (α-terpinene, γ-terpinene, terpinolene, D-limonene, α-pinene) with water, cis-pinonic acid (CPA) and octanoic acid (OA) on the surface of liquid microjets. Significantly, the relative yields of α-hydroxy-hydroperoxides production from CIs hydration at the gas–liquid interface—α-terpinene (1.00) ≫ D-limonene (0.18) > γ-terpinene (0.11) ∼ terpinolene (0.10) ≫ α-pinene (0.01)—do not track the rate constants of their gas-phase ozonolyses. Notably, in contrast with the inertness of the other CIs, the CIs derived from α-terpinene ozonolysis readily react with CPA and OA to produce C_(20) and C_(18) ester hydroperoxides, respectively. Present results reveal hitherto unknown structural effects on the reactivities of CIs at aqueous interfaces.

Hyperspectral technology is particularly good at identifying hydrothermally altered minerals and can offer support for three-dimensional (3-D) alteration modeling of hydrothermal deposit. We propose a 3-D alteration modeling method with hyperspectral core imaging to deepen hydrothermal alteration research for uranium exploration of the Heyuanbei uranium deposit in the western Xiangshan ore field, Jiangxi, South China. We use the following three steps: (1) identify and map the altered minerals of drill cores, (2) quantify all types of altered minerals using a pixel classification-based statistical algorithm, and (3) establish 3-D alteration model using a parallel section and a triangulated irregular network. Hyperspectral core imaging data from 14 drill cores from the Heyuanbei uranium deposit are used to establish a 3-D alteration model of the superimposed stratigraphy and structural information by this method. The modeling results indicate that large-scale illite and kaolinite–dickite alterations have developed in the Heyuanbei deposit. The illite alteration has the following obvious zoning characteristics: (1) the spatial correlation of short-wavelength illite and kaolinite–dickite, which developed in two volcanic formations, is high, and the alteration is stronger in the upper part of the drill cores than in the lower part of the drill cores; (2) the long-wavelength illite is mainly distributed in the lower volcanic formations. The zoning characteristics reveal that the hydrothermal fluid is acidic in the upper cores, whereas in the lower cores, alkaline fluid is present, and the fluid environment has the characteristics of a transition from early alkaline to late acidic conditions. Moreover, the short-wavelength illite is more closely related to fluorite-hydromica-type uranium mineralization than the long-wavelength illite, and the conversion action from long-wavelength illite to short-wavelength illite is favorable for uranium enrichment. Thus, short-wavelength illite, kaolinite, dickite, and fluorite can be used as prospective indicators for uranium exploration in the Heyuanbei mining area and nearby areas.

article i nfo The Wuyishan metallogenic belt, a part of the circum-Pacific tectonomagmatic belt, is considered one of the 19 key metallogenic belts in China because of its abundant mineral resources and vast prospecting potential. Specifically, the North Wuyi area is an important Cu-Pb-Zn polymetal ore-concentrated district in East China. We report new geochronological dates in this area, which suggest that the formation of mineralization- related magmatic rocks have mainly occurred during the Paleozoic and Mesozoic in four stages: the Caledonian (530 Ma to 430 Ma), Early-Middle Jurassic (183 Ma to 160 Ma), Early Cretaceous (140 Ma to 110 Ma), and Late Cretaceous (63 Ma to 85 Ma). The mineralization events are either coeval or slightly post- date the related magmatic activities. Nappe structures are widespread in the North Wuyi area and play an im- portant role in the formation and preservation of ore deposits, as determined from field observations and structural analyses of mining tunnels. The regional distribution and structural styles of the thrust faults in the North Wuyi area and new 40 Ar- 39 Ar dating results (415 Ma to 390 Ma) confirm that intensive tectonic activity during the Early Paleozoic, when the South China Block was about to separate from Gondwana, has wiped out evidence of Caledonian mineralization. All nappe structures with regional scales (several thousand meters) were formed during the Early Cretaceous period, with an 40 Ar- 39 Ar age of 120 Ma to 129 Ma. The thrust direction of the nappe structures is mainly southeast during the Early Cretaceous in the main body and north piedmont of the Wuyi Mountain. These early thrust faults have not only broken or reformed the existing ore deposits, but have also provided hydrothermal ore-forming channels and spaces for metallogen- ism that are coeval or posterior to the thrust. The subsequent nappe structures thrust mainly from southeast to northwest and overprint the previous southeastward thrust faults. Using 40 Ar- 39 Ar dating of the structural belt, U-Pb SHRIMP zircon dating of the wall rocks, and Re-Os dating of the ore formation, we analyze the ge- netic connection between the structures and ore bodies in different ore fields. Our results serve as useful in- formation on prospecting for the latent ore body in the North Wuyi area, especially the ore bodies destroyed by faulting activities.

We demonstrated the detection of the simplest Criegee intermediate CH2OO with a mid-infrared continuous-wave quantum cascade laser (cw-QCL). The rate coefficients for the reactions of CH2OO with SO2 and NO2 were determined to be (3.6 ± 0.1) × 10−11 and (4.4 ± 0.2) × 10−12 cm3 molecule−1 s−1, respectively. The rate coefficient for CH2OO + SO2 reaction was in good agreement with previous values, which suggests that the cw-QCL is a powerful tool in kinetic studies of CH2OO. Keywords: Mid-infrared absorption, Criegee intermediate, Kinetics

There are 18% Swedish who have passed the retirement age of 65 years. This number is projected to rise to 30% by 2030. According to a recent report, seven times more people are admitted to a hospital after falling down than the traffic incidents. Some falling incidents happened because the elderly people step on an unreliable chair in order to take the plates or glass from the upper cabinet, [2]. After conducting a survey, we found that there are 75% elderly people (60-80 years old) who consider that they are not satisfied with the present design of the cabinet. We designed a new device which can make the upper cabinet move automatically. The users can take anything from the upper cabinet conveniently. The device will reduce this type of accident from happening. Det finns 18% svenska som har passerat pensionsåldern 65 år. Denna siffra förväntas stiga till 30% år 2030. Enligt en färsk rapport, är sju gånger fler människor in på sjukhus efter att ha fallit ner än trafikproblemen. Vissa faller incidenter hände eftersom de äldre kliver på en opålitlig stol för att ta plåtarna eller glas från övre skåpet, [2]. Efter att ha utfört en undersökning, fann vi att det finns 75% äldre (60-80 år) som anser att de inte är nöjda med den nuvarande utformningen av skåpet. Vi konstruerade en ny apparat som kan göra den övre skåpet flyttar automatiskt. Användarna kan ta allt från den övre skåpet bekvämt. Enheten kommer att minska denna typ av olyckor från att hända. 0046767523198