Decomposition Of Material Research Articles

Experimental Investigations of the Thermal Decomposition of Wood at the Time of the Fire in the Premises of Domestic Buildings

Consideration was given to the issues relating to safety conditions and security arrangements during the thermal decomposition of wood at the time of the fire in the premises of domestic buildings. The data of experimental investigations obtained for the thermal decomposition of wood were given with the measurement data of the concentration of toxic gases (СО, СО2), oxygen (О2), and temperature depending on time and fire spreading conditions in the premises. The studies were carried out by comparing the changes in the temperature of the solid flammable materials with time and the emission intensity of toxic gas (СО, СО2) under the limited oxygen access at the time of the fire. The research data confirm those obtained for the gaseous atmosphere composition in the premises during the thermal decomposition of the solid flammable materials.

PHOTOGRAMMETRIC TOPOGRAPHIC BASIS OF ARCHAEOLOGICAL SITE

The publication highlights the use of photogrammetry as one of the methods of fixing the topographic base of a site and the creation of the topographic base using a series of photographs. In archaeological science, a qualitatively prepared topographic plan is the basis for combining the results of previous and subsequent works, reconstruction of a realistic model of the site, its micro-relief, a source of accurate measurements of structures and features of the site, and monitoring its current state. There are a number of methods for creating the topo-bases of archaeological sites, starting with the «classic» one using measuring devices (tape measure), a compass, an optical level or theodolite, and ending with high-tech LiDAR technologies.
 One of the methods of creating a topographic base is photogrammetric recording, both on the ground and with the help of low-altitude aerial photography by drone. With the help of a series of photos and their processing in specialized programs, a 3D-model of the object is created.
 The article gives an example of the creation of topo-bases using photogrammetry at two Old Rus hill-forts. The obtained results are compared with the plans of the middle of the 20th century, which were created by researchers by hand. On the basis of the presented orthophoto plans, detailed maps of the heights of both archaeological monuments were created, which became the basis for creating their topographic foundations. For ease of graphic display and perception, heat maps and isolines with markings according to the Baltic system of heights are superimposed on the height maps. Thus, at this stage, ready-made topographic bases of archaeological monuments were created in the following sequence: 1) photogrammetric recording of the area; 2) creation of a 3D-model; 3) creating a photo plan; 4) creating a height map; 5) convenient graphical representation of the topographic map. Topobase serves as a basis for digital recording of archaeological research — both excavations in general and individual objects and each individual find, which allows for spatial analysis of the planning structure, decomposition of objects and material by context and horizons, spatial analysis of the concentration of material in a separate area objects, etc.

Uniform monolayer Cu2ZnSn(S,Se)4 film based on novel precursor solution

In this paper, we reported a novel precursor solution for the preparation of Cu2ZnSn(S,Se)4 (CZTSSe) film. Large-grain monolayer CZTSSe film can be obtained by using the precursor solution. The influence of selenization temperature on the properties of CZTSSe films and solar cells were investigated. We found the monolayer CZTSSe film can be prepared with the selenization temperature as low as 510 °C. While an increased selenization temperature was used, the size of the crystalline grains in CZTSSe film increased significantly, but the decomposition of CZTSSe material got more serious. As the increase of the selenization temperature, increased short-circuit current (JSC) can be achieved for the fabricated solar cell, which could be caused by the improved crystallinity of CZTSSe layer and the enlarged depletion width of solar cell (as much as 391 nm). On the other hand, the open-circuit voltage (VOC) decreased as the increase of selenization temperature, which may relate with the decomposition of CZTSSe material. The best solar cell achieved the efficiency of 11.4% (active area), which was based on CZTSSe film with the selenization temperature of 510 °C.

Interfacial Chemistry of Thiophene As an Effective Film-Forming Additive on High Voltage Cathode Revealed By Operando Raman Spectroscopy

For decades intense research efforts have been aimed at increasing energy densities with new rechargeable lithium battery (RLB) designs to meet the anticipated increasing energy storage demands. These efforts have yielded much higher capacities with novel materials. However, the theoretical capacity of an RLB cell is seeded in the structure of the electrode, while its practical capacity, performance, cycle life, and safety are deep-rooted in the side reactions at the interphase between electrode and electrolyte (interphase is the phase at the electrode-electrolyte interface) 1,2.Interphases are essential for the operation of the cells and have been widely recognized as the "most important and the least understood" components of RLBs3. While their characteristics determine their performance, they are not part of the design of RLBs, but only form during the cell operation on the anodes and cathodes. They constitute passivation layers with mixed chemistries due to the electrolytes' electrochemical stability window (ESW) being smaller than the operating potential of RLBs. Although interphase formation is of functional importance, its formation imposes a heavy price on the cell's performance. Formation of the interphase consumes the electrolyte and active lithium stored in the cathode and causes a dramatic capacity loss, especially in the initial charge/discharge cycles. Also, the presence of the interphase introduces a high level of impedance to the cell, which interrupts the fast and constant flow of Li-ion between the anode and cathode. Last but not least, interphase is an active and complex medium that changes its chemical composition and transport properties during charge/discharge cycling and storing conditions. This results in a constant evolution of the interphase and capacity fading, which is more prominent in the high cell voltage applications. Achieving high cell voltage by increasing the cut-off voltage of LiNi x Co y Mn1−x−y O2 cathode (NMC) materials to 4.5 V is an effective way to enhance the energy density of RLBs4. However, a high level of parasitic and decomposition reactions result in severe capacity fading of the battery cell5.Many efforts have been made to improve the properties of the cathode interphase at high cut-off voltage by incorporating different strategies. The in vivo approach is one of the more successful attempts to design the cathode interphase by incorporating film-forming additives in electrolytes to suppress parasite reactions at the electrode-electrolyte interface6-8. In an ideal case, this film should be stable with cycling and have excellent conductivity for Li+ ions and low electronic conductivity9.Thiophene-based molecules are investigated as effective film-forming on NMC at high cut-off voltages of 4.5 V vs. Li/Li+. Electrochemical investigations show that thiophene oxidizes before carbonate-based electrolytes and forms a stable interphase with high conductivity for Li-ion. Also, the electrochemical performance of the cell is enhanced significantly in the presence of thiophene additive with capacity retention of 95% after 100 cycles (75% capacity retention of the benchmark system). To reveal the underlying mechanisms of the interphase formation and thiophene working principle on the surface of NMC cathode, we performed operando near-field Raman spectroscopy. The Raman and electrochemistry results indicate that a poly-thiophene film is formed that covers the surface of the cathode active materials uniformly, protecting further oxidation of the electrolyte and preventing transition metal dissolution and decomposition of the active cathode materials. (1) Freunberger SA Nature Chemistry 2019, 11, 761. (2) Yang Y, Yan C, Huang JQ Acta Physico-Chimica Sinica 2021, 37. (3) Winter M Zeitschrift Fur Physikalische Chemie-International Journal of Research in Physical Chemistry & Chemical Physics 2009, 223, 1395. (4) Fergus JW Journal of Power Sources 2010, 195, 939. (5) Yan GC, Li XH, Wang ZX, Guo HJ, Wang C Journal of Power Sources 2014, 248, 1306. (6) Zhang L, Zhang ZC, Wu HM, Amine K Energy & Environmental Science 2011, 4, 2858. (7) Liu QY, Yang GJ, Li SW, Zhang SM, Chen RJ, Wang ZX, Chen LQ Acs Applied Materials & Interfaces 2021, 13, 21459. (8) Zhu XB, Schulli T, Wang LH Chemical Research in Chinese Universities 2020, 36, 24. (9) Xu K Chemical Reviews 2014, 114, 11503.

Valorization of spent mushroom substrate in combination with agro-residues to improve the nutrient and phytohormone contents of vermicompost

In recent years, enormous amounts of spent mushroom substrate (SMS) have been generated because of the rapid development of mushroom production. Since the conventional disposal methods of these residues can cause serious environmental problems, alternative waste management techniques are required to ensure sustainable agriculture. However, SMS might be not suitable for vermicomposting when used alone. Therefore, the primary purpose of this study was to investigate the effect of Azolla microphylla (Azolla) biomass, eggshells, fruit peels, and cassava pulp on the biodegradation process of SMS. The results showed the treatments supplemented with cassava pulp and fruit peel waste improved the growth of earthworms, while the carbon-to-nitrogen ratio of these vermicomposts decreased significantly (p < 0.05) due to the improved total nitrogen contents (7.64 g kg−1 and 6.71 g kg−1). Concerning the degradation process and the vermicompost quality, the addition of these agro-residues facilitated the enzyme activities (cellulase, urease, and alkaline phosphatase) and increased the total macronutrient (P, K, Mg, and Ca) and phytohormone (fruit peel waste: AA, GA3, and cytokinin; cassava pulp: cytokinin) contents of the final products compared to the control treatment. On the other hand, Azolla had no additional effect on the fecundity and growth of Eudrilus eugenia. Meanwhile, the treatment supplemented with eggshells was high in Mg (7.15 g kg−1) and Ca (305.6 g kg−1). Overall, the combined decomposition of SMS-based bedding material with Azolla, eggshells, fruit peel waste, and cassava pulp resulted in mature organic fertilizers with improved chemical properties.

Analysis the nutrient of bio-vermicompost with different techniques applications of some microbes and earthworms

Vermicompost is an organic fertilizer resulting from the decomposition of organic materials by utilizing earthworms. The presence of these microorganisms means that vermicompost contains compounds that are needed to increase soil fertility or for plant growth. This study aims to analyze the nutrients of bio-vermicompost with a combination of application techniques of beneficial microbes and earthworms. This study used a factorial Completely Randomized Design (CRD). The first factor is the application of microbes and earthworms with 4 treatments, T0: without earthworm, T1: application microbe followed (one week) by earthworm, T2: application microbe and earthworm in same time, T3: application earthworm followed (one week) by microbe. The second factor is the type of microbe with 4 treatments, M1: Azospirillum sp, M2: Azotobacter chroococum, M3: Trichoderma asperellum, M4: Talaromyces pinophilus. The results showed that the application technique had a significant effect on C-organic, C/N ratio, pH, P2O5, and K2O. The combination of both treatments significantly affect to the water content. The highest N was found in A3M1 (earthworm application followed by Azospirillum) which was 2.19%. The combination of A2M2 (Application of earthworms and Azotobacter at the same time) is the best combination in increasing the content of P2O5 (1.225%) and K2O5 (2.245%).

Temperature and Pressure Effects on HMX/Graphene via ReaxFF Molecular Dynamics Simulations

Studying the thermal decomposition of energetic materials at high temperatures can provide detailed reaction and mechanistic information, which is critical for understanding the reactivity of energetic materials, designing mixed explosives, and achieving improved safety. In this work, the effects of temperature and pressure on graphene (Gr)-based HMX crystals were investigated using ReaxFF molecular dynamics simulations. The thermal decomposition processes of perfect HMX crystals, HMX crystals with (001), (010), or (100) crystal planes, and HMX/Gr mixed systems were studied at high temperatures and pressures. In the mixed systems, different configurations of HMX molecules adsorbed on the Gr surface were confirmed by theoretical calculation methods. With the pressure ranging from atmospheric pressure to 31 GPa, 3, 5, and 3 configurations of HMX adsorbed on the Gr surface were identified for the (001)/Gr, (010)/Gr, and (100)/Gr systems, respectively. The time-dependent curves for the evolution of fragments, intermediates, and pyrolysis products were analyzed. The rate constant for the thermal decomposition of HMX was found to be significantly affected by the addition of Gr. In particular, the thermal decomposition reaction was strongly inhibited in the (010)/Gr system. This result indicates that Gr promotes an anisotropic thermal effect, resulting from the steric hindrance of the NO2 functional groups and the interaction between Gr and HMX molecules. Gr also affected the initial reaction pathway of homolytic N–NO2 bond cleavage, with C=O, C–OH, and C–OC bonds on the Gr surface participating in the formation of nitro radicals and HONO.

Utilization of Eco-Friendly Waste Eggshell Catalysts for Enhancing Liquid Product Yields through Pyrolysis of Forestry Residues

In this study, catalytic and noncatalytic pyrolysis of Prosopis juliflora biomass was carried out in a fluidized bed reactor. This study highlights the potential use of forestry residues with waste eggshells under a nitrogen environment. The experiments were conducted to increase the yield of bio-oil by changing the parameters such as pyrolysis temperature, particle size, and catalyst ratio. Under noncatalytic pyrolysis, a maximum bio-oil yield of 40.9 wt% was obtained when the feedstock was pyrolysed at 500°C. During catalytic pyrolysis, the yield of bio-oil was increased by up to 16.95% compared to the noncatalytic process due to the influence of Ca-rich wastes on devolatilization behavior. In particular, the existence of alkali and alkaline-earth metals present in eggshells might have positive effects on the decomposition of biomass material. The bio-oil obtained through catalytic pyrolysis under maximum yield conditions was analyzed for its physical and chemical characterization by Fourier transform infrared (FT-IR) spectroscopy and gas chromatography mass spectroscopy (GC-MS).

Effect of riparian soil moisture on bacterial, fungal and plant communities and microbial decomposition rates in boreal stream-side forests

Riparian habitats of boreal forests are considered as hotspots for biochemical processes and biodiversity, and varying width riparian buffers have been proposed to protect species diversity of the riparian forests. However, evidence of the role of soil moisture variation in shaping riparian biodiversity and ecosystem functioning remain scarce particularly regarding belowground diversity. We studied how distance from the stream and soil moisture of the riparian zone affected species richness and community composition of plants, bacteria, and fungi as well as microbial decomposition rates. Using a split-plot design with a plant survey and amplicon sequencing for microorganisms we identified taxa associated with different categories of moisture and distance from the stream along six headwater stream-sides in middle boreal forests in Northern Finland. Tea-bag Index was used to assess the decomposition rates. PERMANOVA and linear mixed-effect models were used to analyze the data. Variation in riparian soil moisture influenced species composition and richness of plants and bacteria. Plant communities also changed from herbaceous dominated to shrub dominated with increasing distance from the stream. Fungal communities, however, did not respond to soil moisture or distance from the stream, and there were only slight differences in fungal trophic guilds among moisture and distance categories. Decomposition of organic material by microorganisms was faster adjacent to the stream than further away, and moist riparian areas had higher decomposition rates than drier ones. Decomposition rates were positively related to pH, Ca, Mg and NH4 and soil temperature.Synthesis and applications We show that above- and belowground diversity and microbial decomposition are associated to soil moisture at riparian sites supporting the idea of leaving wider unmanaged buffers in moist habitats to safeguard the overall forest diversity. Our findings further emphasize the need to consider soil moisture when planning the measures for riparian protection as changes in riparian soil moisture could lead to deterioration of organic matter decomposition. Different responses of the examined plant and microbial communities to riparian soil conditions clearly imply that overall riparian diversity cannot be explained based on a single community type, and that different organisms may respond differently to human-induced changes in stream riparian zone.

Characterizing and predicting 21700 NMC lithium-ion battery thermal runaway induced by nail penetration

• Pioneering CFD predictions of nail penetration induced TR in 21700 cylindrical cells. • Internal heat generation is coupled with external convective and radiative heat exchange. • New tests to establish the differences in radial and axial penetration of cylindrical cells. • Fill experimental gaps by quantify the effects of contact resistance and external heat transfer. • The generic nature of the CFD based predictive tool can be easily adapted for other cell types. Combined numerical and experimental studies are conducted to characterise 21,700 cylindrical lithium-ion battery (LIB) thermal runaway (TR) induced by nail penetration. Both radial and axial penetrations are considered for 4.8 Ah 21,700 NMC cell under 100% state of charge. Heat generation from the decomposition of the cell component materials are analysed. The maximum cell surface temperature rise and time to reach it in both types of penetration tests are compared. Snapshots from the video footages captured by three high definition and one high speed cameras shade light on the dynamic processes of spark ejection and flame evolution. A generic predictive tool is developed within the frame of the in-house version of open-source computational fluid dynamics code OpenFOAM for nail induced TR. The code treats the cell as a lumped block with anisotropic thermal conductivities and considers heat generation due to nail induced internal short circuit resistance, exothermic decomposition reactions and heat dissipation through convective and radiative heat transfer. Validation with the current measurements shows promising agreement. The predictions also provide insight on the magnitudes of heat generation due to internal short circuit resistance, decompositions of solid electrolyte interphase layer (SEI), anode, cathode and electrolyte. Parametric studies further quantify the effects of cell internal short circuit resistance, contact resistance between the nail and cell, convective heat transfer coefficient and cell surface emissivity on TR evolution.

Subsidence and Percentage of CO2 Emission from Decomposition to Subsidence of Peatland on Oil Palm Plantations

Peatlands drainage system aimed to eliminate the limiting factors to support better growth of plants. Drainage practices will cause subsidence and be associated with CO2 emission. The purpose of this study was to observe the subsidence rate on tropical peatlands of oil palm plantations at different ages and to establish the percentage of decomposition of peat materials from the subsidence rate. Subsidence was measured in 9-, 12-, and 17-year-old of adjacent oil palm planting blocks with peat thickness of about 5 m and have been drained for 10–18 years, two samples taken for each block every three month. Peat decomposition was measured in the 12-year-old block automatically using LiCor Li-8100A with 30 minutes recording interval. Peat decomposition (heterotrophic respiration) considered as actual CO2 emission was compared to emission calculated from subsidence and considered as potential CO2 emission. The average subsidence rate observed for one year in the three age classes of oil palm plantations was 2.47 ± 0.76 cm/year. The percentage of CO2 emissions from the decomposition process to subsidence on drained 12-year-old oil palm on tropical peatlands was 41.05%. The subsidence data indicates that consolidation still the main process of subsidence in this peatland.

Synthesis and Electrochemical Characterization of LiNi0.5Co0.2Mn0.3O2 Cathode Material by Solid-Phase Reaction.

In this paper, using four carbonates as raw materials, the cathode material LiNi0.5Co0.2Mn0.3O2 was prepared with the “ball milling-calcining” solid-phase synthesis method. The specific reaction process, which consists of the decomposition of the raw materials and the generation of target products, was investigated thoroughly using the TG-DSC technique. XRD, SEM and charge/discharge test methods were utilized to explore the influence of different sintering temperatures on the structure, morphology and electrochemical performance of the LiNi0.5Co0.2Mn0.3O2 cathode. The results show that 900~1000 °C is the appropriate synthesis temperature range. LiNi0.5Co0.2Mn0.3O2 synthesized at 1000 °C delivers optimal cycling stability at 0.5 C. Meanwhile, its initial discharge specific capacity and coulomb efficiency reached 167.2 mAh g−1 and 97.89%, respectively. In addition, the high-rate performance of the cathode sample prepared at 900 °C is particularly noteworthy. Cycling at 0.5 C, 1 C, 1.5 C and 2 C, the corresponding discharge specific capacity of the sample exhibited 148.1 mAh g−1, 143.1 mAh g−1, 140 mAh g−1 and 138.9 mAh g−1, respectively.

Study on catalytic decomposition of vehicle exhaust pavement materials by TiO2

To achieve low-carbon development and reduce greenhouse gas emissions, it is urgent to solve the problem of automobile exhaust emissions. The photocatalytic material nano titanium dioxide is applied to asphalt pavement to realize the catalytic decomposition of automobile exhaust gas, and achieve the purpose of energy conservation, emission reduction, and environmental protection. In this paper, the photocatalytic efficiency of tail gas degradation of TiO2 thin layer asphalt mixture and TiO2 micro surface asphalt mixture was studied, and the influence of different light intensity on the photocatalytic efficiency of tail gas degradation of the mixture was analyzed. The results show that, with the increase of TiO2 content in the mixture, the tail gas degradation efficiency of the TiO2 thin layer and TiO2 micro surface type mixture increases at first and then becomes stable. In the TiO2 thin layer mixture, when the content of TiO2 reaches 90% (accounting for the mass of ore powder), the cumulative decomposition rates of NO, HC and CO are 43.8%, 19.5%, and 26.1%, respectively, under outdoor natural light. Under ultraviolet light, the cumulative decomposition rates of NO, HC, and CO were 50.6%, 25.12% , and 29.33%, respectively. In the TiO2 microsurface type mixture, when the content of TiO2 reaches 75%(accounting for the mass of ore powder), the cumulative decomposition rates of NO, HC, and CO are 49%, 24.3%, and 26%, respectively, under outdoor natural light. Under ultraviolet light, the cumulative decomposition rates of NO, HC, and CO were 53.9%, 27.6%, and 29.8% respectively. Therefore, compared with outdoor natural light, the asphalt mixture with the same TiO2 content has a higher cumulative decomposition rate of NO, HC, and CO under ULTRAVIOLET light. Under the same experimental conditions, the utilization efficiency of TiO2 microsurface type mixture for TiO2 photocatalyst is better than that of TiO2 thin layer type mixture. Considering the degradation effect of tail gas and the utilization efficiency of TiO2 photocatalyst, the optimal TiO2 content of thin layer mixture is 60% (accounting for the mass of ore powder), and that of micro surface type mixture is 50% (accounting for the mass of ore powder).

Conservation management and termites: a case study from central Côte d’Ivoire (West Africa)

AbstractTermites are essential components of tropical ecosystems, in which they provide fundamental ecosystem services, such as decomposition of dead plant material, fostering of soil mineralization and provisioning of new microhabitats. We investigated the termite communities of four habitats in two protected areas in West Africa, which differ in management effectiveness: the strictly protected Lamto Reserve (LR) and the Marahoué National Park (MNP), which suffers from anthropogenic disturbance despite its protection status. We tested the effect of disturbance on species composition, richness and abundance as well as on functional (feeding type) composition. The effect of disturbance was clearly visible in the termite communities. Compared to the LR, the MNP had less termite species overall and in all habitats except the shrub savannah. Also the abundance of termites was generally reduced and a decrease of soil feeders recorded. The latter is well-known to be sensitive to anthropogenic disturbance in forests. Comparing our results with other studies, we were able to identify suitable bioindicators of ecosystem health for West-African savannahs. Furthermore, we discuss the potential consequences of anthropogenic disturbance on ecosystem services provided by termites.

REDD+ Strategy for forest carbon sequestration in India

Deforestation and forest degradation due to land use, land cover change (LULCC) have become one of the prime contributors to global greenhouse gas (GHG) emissions, after fossil fuel combustion. Greenhouse gas emission from forestry is occurring in the atmosphere as a result of forest biomass combustion, forest fires and decomposition of deadwood materials. This is how increasing carbon dioxide in the atmosphere is adding to the global warming and climate change. Many worldwide recognized studies have measured that forest ecosystems have the capacity to absorb more than 1/3rd of total carbon dioxide from the atmosphere which is the minimum requirement for keeping the atmospheric temperature under 2 °C by 2030. One of the commonly accepted methods for reducing carbon is carbon sequestration through forests. India has committed to capture 2.5 to 3 billion tonnes of CO2 by enhancing forest and tree cover through 2030. To achieve this target, India has adopted REDD+ (Reducing Emissions from Deforestation and Forest Degradation) strategy which aims to mitigate climate change by enhancing forest carbon sequestration through incentivizing forest conservation. Furthermore, this strategy strives to address the drivers of forest degradation and deforestation and also provides a roadmap for forest carbon stocks enhancement and sustainable forest management through REDD+ actions. This study investigates REDD+ contribution against global warming and climate change in India through forest carbon sequestration.

Abandoned Wood Ant Nests as Sites for Seedling Germination

We compared the species composition of seedlings germinated on ten recently abandoned Formica polyctena nests with the plant species on active nests and the plant species composition of the forest floor around the nests. Compared to no plants at all, when the nests were inhabited, seedlings of 12 different vascular plant species germinated on the nests after their abandonment. Four of them were myrmecochorous, of which two occurred only on the nests. After abandonment, ant activity ceases, the water content of the nests increases, and decomposition of the organic nest material is accelerated, resulting in faster nutrient mineralization. Consequently, more nutrients are available for plants. Our results suggest that abandoned nests can serve as “regeneration niches”, ensuring genetic diversity, especially in plant populations which rely mainly on vegetative propagation. However, more research on a larger scale is needed to assess the role of wood ants and their abandoned nests in forest vegetation development.

Modified sol-gel synthesis of lithium ternary oxide

Lithium-ion batteries currently equip portable electronic devices, such as smartphones and laptops, and are the choice to power electric vehicles. The scarcity of raw materials in nature, however, has required the development of new technologies and the ternary lithium compound LiNi1/3Mn1/3Co1/3O2 has stood out as an alternative for replacing part of the cobalt in LiCoO2 by nickel and manganese, which are more abundant, reducing the electrode’s cost. The sol-gel route for synthesis of ternary electrode materials has been widely used, but it faces problems of volumetric expansion due to the decomposition of organic material during calcination. To improve the synthesis of the ternary compound, a modified sol-gel route with control of the heating kinetics in the pre-calcination step and without pH control was investigated in this study. The compound was analyzed by X-ray diffraction, Rietveld refinement, Fourier transform infrared absorption spectroscopy, and Raman that showed the purification of the ternary phase with appropriate crystallinity for application as electrode in batteries from 700 ºC. In conclusion, ternary synthesis with rate control during heat treatment may be a useful alternative for industrial scale-up production.

Synthesis of Carbon Nanoparticles with Cobalt-Rich Shell via Pyrolysis of Zn-ZIF@Co/Zn-ZIF: Relevance of Co(III) Precursors

To the best of our knowledge, this is the first report on the rapid one-pot synthesis of a unique core-shell-structured zeolitic imidazolate framework (ZIF) using Co(III) and Zn(II) precursors. The key to obtaining this unique structure is the use of a Co(III) precursor as the starting material. Transmission electron microscopy (TEM) reveals that Co was present within a 30-nm-thick shell layer of the ZIF material. Thermal decomposition of the ZIF material affords core-shell-structured carbon nanoparticles that have Co on the external surface of the carbon grain. We have previously demonstrated that this carbonaceous material obtained by thermal decomposition exhibited high performance as an adsorbent for nitric oxide, even in the presence of excess oxygen and water vapor, and therefore, it was a suitable material for NOx elimination at low temperatures. The growth mechanism of the synthesized ZIF particles and the differences between synthesized ZIF and conventional Co(II)-ZIF-67 are discussed. The reactivity of the Co(III) precursor is much lower than that of the Co(II) species, leading to slower precipitation of Co(III) than that of Zn(II), thus forming the core-shell structure.

Elastic Properties of Poly(ethylene glycol) Nanomembranes and Respective Implications.

Free-standing poly(ethylene glycol) (PEG) membranes were prepared from amine- and epoxy-terminated four-arm STAR-PEG precursors in a thickness range of 40–320 nm. The membranes feature high stability and an extreme elasticity, as emphasized by the very low values of Young’s modulus, varying from 2.08 MPa to 2.6 MPa over the studied thickness range. The extreme elasticity of the membranes stems from the elastomer-like character of the PEG network, consisting of the STAR-PEG cores interconnected by crosslinked PEG chains. This elasticity is only slightly affected by a moderate reduction in the interconnections at a deviation from the standard 1:1 composition of the precursors. However, both the elasticity and stability of the membranes are strongly deteriorated by a strong distortion of the network imposed by electron irradiation of the membranes. In contrast, exposure of the membranes to ultraviolet (UV) light (254 nm) does not affect their elastic properties, supporting the assumption that the only effect of such treatment is the decomposition of the PEG material with subsequent desorption of the released fragments. An analysis of the data allowed for the exclusion of so called “hot electrons” as a possible mechanism behind the modification of the PEG membranes by UV light.

Ecuadorian Coptoborus beetles harbor Fusarium and Graphium fungi previously associated with Euwallacea ambrosia beetles

ABSTRACT Ambrosia beetles from the scolytine tribe Xyleborini (Curculionidae) are important to the decomposition of woody plant material on every continent except Antarctica. These insects farm fungi on the walls of tunnels they build inside recently dead trees and rely on the fungi for nutrition during all stages of their lives. Such ambrosia fungi rely on the beetles to provide appropriate substrates and environmental conditions for growth. A small minority of xyleborine ambrosia beetle–fungal partnerships cause significant damage to healthy trees. The xyleborine beetle Coptoborus ochromactonus vectors a Fusarium (Hypocreales) fungus that is lethal to balsa (Ochroma pyramidale (Malvaceae)) trees in Ecuador. Although this pathogenic fungus and its associated beetle are not known to be established in the United States, several other non-native ambrosia beetle species are vectors of destructive plant diseases in this country. This fact and the acceleration of trade between South America and the United States demonstrate the importance of understanding fungal plant pathogens before they escape their native ranges. Here we identify the fungi accompanying Coptoborus ambrosia beetles collected in Ecuador. Classification based ribosomal internal transcribed spacer 1 (ITS) sequences revealed the most prevalent fungi associated with Coptoborus are Fusarium sp. and Graphium sp. (Microascales: Microascaceae), which have been confirmed as ambrosia fungi for xyleborine ambrosia beetles, and Clonostsachys sp. (Hypocreales), which is a diverse genus found abundantly in soils and associated with plants. Phylogenetic analyses of the Fusarium strains based on ITS, translation elongation factor (EF1-α), and two subunits of the DNA-directed RNA polymerase II (RPB1 and RPB2) identified them as Fusarium sp. AF-9 in the Ambrosia Fusarium Clade (AFC). This Fusarium species was previously associated with a few xyleborine ambrosia beetles, most notably the species complex Euwallacea fornicatus (Eichhoff 1868) (Curculionidae: Scolytinae: Xyleborini). Examination of ITS and EF1-α sequences showed a close affinity between the Graphium isolated from Coptoborus spp. and other xyleborine-associated Graphium as well as the soil fungus Graphium basitruncatum. This characterization of ambrosia fungi through DNA sequencing confirms the identity of a putative plant pathogen spread by Coptoborus beetles and expands the documented range of Fusarium and Graphium ambrosia fungi.