Amount Of Sulfur Research Articles

A paleo-bioclimatological study on gondwana coal deposits in northwestern Bangladesh and the associated environment reflected by pollen and geochemical analysis

To comprehend the realistic paleo-bioclimate and depositional environment, we need to clearly grasp the methods that can be used to track paleoclimate in the past. The present research has focused on palynological investigation, X-ray Diffraction analysis, and elemental analysis of the core coal samples of the Gondwana coal of the Barapukuria Basin. The palynological study identifies two Palynoassemblage zones (Zone I and Zone II). A non-striate desiccate Scheuringipollenite, Crucisaccites, Parasaccites palynoassemblages are identified as Zone I and denotes as Lower Barakar Palynozone in the Early Permian where Zone II is dominated by striate desiccate Barakarites, Faunipollenites, Callumispora Palynoassemblages in the Late Permian. The Glossopterid plant family ruled the botanical affinity of Zone I and Zone II. It rendered the Gymnosperm group of plants as the rapid deglaciation assisted dissemination of Glossopteris flora. Higher percentages of clay minerals in X-ray diffraction (XRD) analysis and higher amounts of carbon content, lower sulfur, and higher C/S>10 ratio in the elemental analysis have been identified. All evidence from the research suggests that coals were deposited when glaciers retreated in the Early Permian, and the Gymnosperm group of plants prevailed and accumulated in the warm and humid climatic conditions under the braided fluvial influence in the terrestrial environment. J. Asiat. Soc. Bangladesh, Sci. 49(1): 101-119, June 2023

Novel Sulfate Reduction Coupled to Simultaneous Nitrification and Autotrophic Denitrification Process for Removing Nitrogen and Organics from Saline Wastewater.

Highly efficient sulfate reduction coupled to autotrophic denitrification plus nitrification is demonstrated by integrating an anaerobic membrane bioreactor (AnMBR) with a membrane aerated biofilm reactor (MABR). Concurrent chemical oxygen demand (COD) removal and sulfate reduction were accomplished in the AnMBR, while simultaneous nitrification and autotrophic denitrification were carried out in the MABR. Separate operation of the MABR achieved >90% total nitrogen (TN) removal when the N/S ratio was controlled at 0.4 gN/gS. The integrated AnMBR-MABR system efficiently resisted influent variability, realizing >95% COD removal in the AnMBR and >75% TN removal in the MABR when the influent COD/N ratio was above 4 gCOD/gN. Membrane fouling did not happen during ∼170 days of operation. Due to sulfide oxidation, a large amount of elemental sulfur (S0) accumulated in the MABR biofilm, where it served as an electron donor for denitrification. Microbial community analysis indicated that Nitrospira and Thiobacillus played key roles in nitrification and sulfide-driven denitrification, respectively, and that they occurred in different layers of the biofilm. This novel process offers advantages of a small land-area footprint, modular operation, and high efficiency electron-donor and oxygen utilizations, particularly for wastewater with a low COD/N ratio.

The role of organic carbon in the Southern Uplands-Down-Longford Terrane accretionary prism, Scotland and Ireland

Carbonaceous shales in the Southern Uplands-Down-Longford Terrane accretionary prism had extremely high potential for hydrocarbon generation in the Lower Paleozoic. Structural thickening in the prism enhanced the rapid generation of oil. Shale horizons are separated by thick turbidites composed of low-permeability greywackes, so oil under high fluid pressure either pooled along shale bedding surfaces or migrated into fractured greywackes. Pooled oil became solidified to bitumen, which locally formed deposits on a scale of tonnes, mined as coal. The carbon-rich shale also sequestered large amounts of sulfur from seawater, which precipitated as pyrite firstly during early diagenesis, then further during fluid flow through the shale beds. The oil was also sulfur-bearing. Deformation focused on the shale beds during the evolution of the accretionary prism would have been closely related to the fluid flow which precipitated bitumen and sulfides. The palaeo-fluids were also anomalously rich in methane and hydrogen, similar to fluids venting from modern accretionary prisms. Supplementary material: details of localities searched for coal in Lower Palaeozoic, Southern Uplands-Down-Longford Terrane (locations shown in Fig. 6 ) are available at https://doi.org/10.6084/m9.figshare.c.6691597

Impact of a strong volcanic eruption on the summer middle atmosphere in UA-ICON simulations

Abstract. Explosive volcanic eruptions emitting large amounts of sulfur can alter the temperature of the lower stratosphere and change the circulation of the middle atmosphere. The dynamical response of the stratosphere to strong volcanic eruptions has been the subject of numerous studies. The impact of volcanic eruptions on the mesosphere is less well understood because of a lack of large eruptions in the satellite era and only sparse observations before that period. Nevertheless, some measurements indicated an increase in mesospheric mid-latitude temperatures after the 1991 Pinatubo eruption. The aim of this study is to uncover potential dynamical mechanisms that may lead to such a mesospheric temperature response. We use the Upper-Atmospheric ICOsahedral Non-hydrostatic (UA-ICON) model to simulate the atmospheric response to an idealized strong volcanic injection of 20 Tg S into the stratosphere (about twice as much as the eminent 1991 Pinatubo eruption). Two experiments with differently parameterized effects of sub-grid-scale orography are compared to test the impact of different atmospheric background states. The simulations show a significant warming of the polar summer mesopause of up to 15–21 K in the first November after the eruption. We argue that this is mainly due to intrahemispheric dynamical coupling in the summer hemisphere and is potentially enhanced by interhemispheric coupling with the winter stratosphere. This study focuses on the first austral summer after the eruption because mesospheric temperature anomalies are especially relevant for the properties of noctilucent clouds, whose season peaks around January in the Southern Hemisphere.

Purified Glycerine from Biodiesel Production as Biomass or Waste-Based Green Raw Material for the Production of Biochemicals

Glycerine (glycerol) is a polyol consisting of three carbon atoms bonded to hydroxyl groups. It is a by-product of the transesterification of triglycerides, such as animal fats, vegetable oils, or used cooking oils during the biodiesel production process. Crude glycerine is subject to purification processes resulting in distilled glycerine containing at least 99.5% glycerol. Currently, produced high-quality distilled glycerine is used in the food, pharmaceutical, and cosmetic industries. Recently, technologies for converting glycerol to other chemicals through catalytic processes have been intensively developed, e.g., production of bio-based 1,2-propanediol. In the near future, glycerol will certainly become a promising renewable raw material in many modern biorefineries for the synthesis of biofuels, chemicals, and bioenergy production. This paper presents the possibility of using ion exchange resins to remove impurities with trace amounts of sulphur and nitrogen compounds from crude and distilled glycerine, produced during the biodiesel production process from used cooking oils. It was determined that using ion exchange resins at the preliminary purification stage (before distillation) was ineffective. Using cationite resins to purify distilled glycerine produced from waste materials enables the removal of impurities in the form of sulphur and nitrogen compounds.

Arsenic transformation and redistribution in groundwater induced by the complex geochemical cycling of iron and sulfur

Iron (hydr)oxides are effective sorbents of arsenic that undergo reductive dissolution when exposed to dissolved sulfide, which significantly impacts the movement and repartition of arsenic in groundwater. This study investigated the sulfidation of As-bearing ferrihydrite and its consequences on arsenic repartitioning as well as formation and transformation of secondary minerals induced by sulfide in batch experiments. The sulfidation of As(III) and As(V) adsorbed on ferrihydrite shows very different results. In the As(V) system, sulfidation resulted in the production of significant amounts of elemental sulfur (S0) and Fe2+, and Fe2+ and sulfide combine to form mackinawite. Subsequently, Fe2+ adsorbed and catalyzed the conversion of residual ferrihydrite to lepidocrocite. However, in the As(III) system, As(III) was protonated in the presence of sulfide to produce thioarsenate, which accounted for 87.9 % of the total aqueous arsenic concentration. The formation of thioarsenate also consumed the S0 produced by the sulfidation, resulting in no detectable S0 during solid phase characterization. The adsorption of thioarsenate on iron minerals notably affected the surface charge density of ferrihydrite, hindering the further formation of secondary minerals. Studies on the influence of thiolation on As-Fe-S system are of great significance for understanding the migration and redistribution of arsenic in groundwater systems under sulfur-rich conditions.

Treatment of copper-containing leaching residue by sulfation roasting followed by acid/water leaching

This research investigates the extraction of copper from copper-containing leaching residue, which includes 33.45% of copper, 14.14% of iron, 23.87% of sulfur and trace amounts of silver and other elements. Roasting the copper-containing residue under air and oxygen flow convert sulfides into sulfate, followed by water and acid leaching to extract copper. The process parameters, including leaching temperature, sulfuric acid concentration, leaching time, solid-to liquid ratio, and agitation speed, were optimized for both water and acid leaching methods. Results showed that the maximum copper dissolution efficiency was 93.12% with water leaching, and 97.16% with acid leaching. Chemical analysis revealed that the water and acid leaching residue contained 48.13% and 31.64% of iron, respectively. This study provides valuable insights into the process optimization for copper extraction from copper-containing leaching residue, which can inform the development of more efficient and sustainable methods for metal recovery.

Comment on “An approach to sulfate geoengineering with surface emissions of carbonyl sulfide” by Quaglia et al. (2022)

Abstract. Solar radiation management through artificially increasing the amount of stratospheric sulfate aerosol is being considered as a possible climate engineering method. To overcome the challenge of transporting the necessary amount of sulfur to the stratosphere, Quaglia and co-workers suggest deliberate emissions of carbonyl sulfide (OCS), a long-lived precursor of atmospheric sulfate. In their paper, published in Atmospheric Chemistry and Physics in 2022, they outline two scenarios with OCS emissions either at the Earth's surface or in the tropical upper troposphere and calculate the expected radiative forcing using a climate model. In our opinion, the study (i) neglects a significantly higher surface uptake that will inevitably be induced by the elevated atmospheric OCS concentrations and (ii) overestimates the net cooling effect of this OCS geoengineering approach due to some questionable parameterizations and assumptions in the radiative forcing calculations. In this commentary, we use state-of-the-art models to show that at the mean atmospheric OCS mixing ratios of the two emissions scenarios, the terrestrial biosphere and the oceans are expected to take up more OCS than is being released to reach these levels. Using chemistry climate models with a long-standing record for estimating the climate forcing of OCS and stratospheric aerosols, we also show that the net radiative forcing of the emission scenarios suggested by Quaglia and co-workers is smaller than suggested and insufficient to offset any significant portion of anthropogenically induced climate change. Our conclusion is that a geoengineering approach using OCS will not work under any circumstances and should not be considered further.

Revealing the Electrochemistry of All-Solid-State Li-SeS2 Battery via Transmission Electron Microscopy

Li-SeS2 batteries balance the opposing and complimentary qualities of Li-S and Li-Se batteries by having a high specific capacity and high electrical conductivity. However, there is still a lack of knowledge regarding the electrochemical characteristics of Li-SeS2 all-solid-state batteries (ASSB). Herein, transmission electron microscopy (TEM) is used to reveal the electrochemistry of a Li-SeS2 battery. It is discovered that, without the Polyethylene glycol (PEG), amorphous SeS2 in Li-SeS2 ASSB change into crystalline selenium and a small amount of sulfur. The continuous loss of sulfur from the active material may be related to the failure of the cell at 15 cycles and the severe instability of the Coulombic efficiency. It was found that the PEG coating selenium disulfide graphene composite (PEG@rGO-SeS2) cathode maintained a specific capacity of 258 mAh g−1 and a stable Coulombic efficiency of about 97% after 50 cycles. TEM analysis shows that the charging product remains as a granular amorphous selenium disulfide with a constant Se/S ratio during cycling. The PEG-protected selenium disulfide can effectively limit the loss of elemental sulfur and regulate the reaction mechanism of the Li-SeS2 batteries.

Hydrodeoxygenation of lignin-derived diphenyl ether on in situ prepared NiMoS catalyst: The effect of sulfur addition on catalyst formation

The catalytic activity of unsupported NiMoS catalysts prepared in situ by thermal decomposition of the [(CH3)3S]2Ni(MoS4)2 precursor was studied in the course of diphenyl ether hydrodeoxygenation. The resulting catalysts were characterized using the transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). It was demonstrated that the diphenyl ether conversion naturally decreases with a decrease in the precursor loading. The effect of changes in the amount of the added sulfiding agent on the morphological and structural features of the formed catalysts was studied. It was found that reducing the amount of elemental sulfur from 2.5 to 0.5 wt% results in a more active sulfide NiMo catalyst, which is explained by an increase in the dispersion of the active phase particles from 0.24 to 0.34. A route of diphenyl ether hydrodeoxygenation on unsupported NiMoS catalysts was studied and suggested by varying the reaction time and hydrogen pressure in the system.

Metallurgical evaluation and failure analysis of turbo expander Tie-bolt

Failure in a turbo-expander Tie-Bolt (stud) made of superalloy A-286 was investigated. The evaluation of the chemical composition and tensile properties confirmed compliance with the relevant standard. However, the coarsening of γ′ due to over aging condition, the non-uniform grain size and banded coarse MC carbide particles, the segregation of phosphorus to grain boundaries and the growth of carbide particles at the grain boundaries led to a decrease in fatigue strength of the alloy. Fractography studies showed that fracture occurred due to primary axial and secondary bending loads. Multiple ratchets and tire tracks on the fracture surface were consistent with low-cycle fatigue (LCF) failure mechanism. Fatigue striations spacing and micro hardness profile of the threads were used to calculate the stress amplitude and estimate the fatigue strength of Tie-bolt. Neuber’s rule was used to estimate the local stress and strain in the thread root. The calculation results showed that the failure occurred due to the application of cyclic loads at a stress level lower than fatigue strength of the stud. A large amount of sulfur detected at the multiple cracks initiation areas by EDS analysis, indicated the presence of H2S in the environment, which has caused cathodic hydrogen charge and reducedthe steel ductility and accelerated fatigue crack nucleation and growth.

Extractive Distillation Approach to the Separation of Styrene from Pyrolysis Gasoline Feedstock Coupled with Deep Desulfurization

The separation of mixtures with close boiling points is a critical task in the petrochemical industry, and one such mixture that requires separation is o-xylene/styrene. The STED process is used to separate o-xylene/styrene, which contains a certain amount of organic sulfur in the product due to the limitations of the process. In this study, the process underwent enhancements to attain the effective separation of styrene and accomplish deep desulfurization. A mixture of sulfolane (SUL) and N-methylpyrrolidone (NMP) was selected as the extraction solvent after calculating the UNIFAC group contributions. An orthogonal experiment was conducted to investigate the effects of the solvent/oil ratio, reflux ratio, water addition rate, and solvent ratio on the product. The correspondence between each factor and the indexes examined was determined, enabling the optimization and prediction of the styrene product quality. The final optimized conditions for the extractive distillation column are as follows: solvent/oil ratio of 7, reflux ratio of 4.5, water addition rate of 6000 kg/h, and a solvent ratio of 9:1. Under optimal conditions, the purity of the product was observed to be greater than that of the original process and the sulfur content of the product can be reduced to lower than 10 ppm at the cost of an increase of 12.31% in energy consumption.

Symmetrical Diacetylenes Outfitted with Ionic Liquid-like Groups: Structural, Polymerization, and Carbonization Studies

Three symmetrical diacetylenes (DAs) bearing tetraalkylammonium substituents have been prepared, namely, 1,6-bis(triethylammonium)hexa-2,4-diyne diiodide (2), dinitrate (3), and bis[bis(trifluoromethylsulfonyl)imide] (4). For these three salts, the duality between polymerization and carbonization has been investigated, and the results have been rationalized in terms of solid-state organization and molecular structure. These DAs have been irradiated at 254 nm with concomitant annealing at 80 °C (4) or 110 °C (2 and 3), and the lack of polydiacetylene (PDA) formation is in agreement with the fact that the C≡C–C≡C rods do not have a suitable orientation for 1,4-addition. Compound 4 is an ionic liquid. This DA starts melting at 88 °C with a maximum peak value of 104 °C, as ascertained by differential scanning calorimetry and thermogravimetric analyses. It is stable in the liquid state at 120 °C for several hours and remains unchanged at 170 °C for a few minutes without any sign of PDA formation, which means that if some kind of organization exists in the liquid phase, it is not helpful for 1,4-polymerization. Thermolyses of 2–4 have been conducted under a nitrogen flow up to 220 °C (3) and 1200 °C (2 and 4). In all three cases, graphite-like carbon materials were obtained. The graphite-like structures start to form around 200 °C, which is the temperature at which cycloaromatization of the triple bonds takes place. The residues from the pyrolyses of 2 and 4 exhibit nitrogen contents of 1.75 and 1.40 wt %, respectively, and powder X-ray diffraction and Raman analyses indicate that these materials have coherently scattering domain sizes in the range of 1–3 nm depending on the crystallographic direction. The Brunauer, Emmett, and Teller specific surface area of 2@1200 derived from dinitrogen sorption experiments is 88 m2 g–1 and that of 4@1200 is 33 m2 g–1. These values are much higher than those measured in previous works for carbon residues prepared at 1100 °C from imidazolium- and benzimidazolium-appended diacetylenes, thereby highlighting the pivotal influence of the size of the cation on the microstructure of the resulting carbon material. In addition, 2@1200 appears to be mostly microporous and 4@1200 mesoporous, which suggests that the anion also plays a central part in the structuring of the final solid. Last, X-ray photoelectron spectroscopy analysis of 4@1200 indicates that, besides nitrogen, this residue also contains small amounts of fluorine and sulfur, thus making carbonization of ionic diacetylenes an alternative method to introduce doping elements in a graphite structure.

Residential Water Softeners Release Carbon, Consume Chlorine, and Require Remediation after Hydrocarbon Contamination.

Water quality impacts of new ion exchange point-of-entry residential softeners and their ability to be decontaminated following hydrocarbon exposure were investigated. During startup, significant amounts of total sulfur (445 ± 815 mg/L) and total organic carbon (937 ± 119 mg/L) were released into the drinking water that flowed through the softeners. Particulate organic carbon was released until the third regeneration cycle, and resin may also have been released. After one week of device use, softeners continued to cause organic carbon levels to be four to five times greater than background levels. Leached materials from the ion-exchange resin contributed to chlorine decay. When resins were exposed to hydrocarbon-contaminated water, they sorbed benzene, toluene, ethylbenzene, and xylenes (BTEX) and then desorbed the contaminants into drinking water during a 15 day flushing decontamination period. On day 15, benzene exceeded the federal drinking water limit for two of the four resins. The aged resin contributed to the greatest chlorine decay rates and sorbed and then retained the least amount of BTEX. Scale and biofilm on the aged resin likely prompted disinfectant reactivity and inhibited BTEX diffusion into the resin. Study results show that softeners exposed to hydrocarbon-contaminated water may need to be repeatedly flushed to remove BTEX contamination or be replaced. Additional work is recommended to better understand softener impacts on drinking water quality.

Mechanistic study in sulfur-carbon co-modification on Li2FeSiO4 for lithium-ion batteries

Lithium iron silicate (Li2FeSiO4) has high theoretical capacity of 332 mAh∙g-1 upon full extraction of two lithium ions, which is accompanied by high delithiation potential and large volume change. Sulfur modification could be an effective approach for stabilizing Li2FeSiO4 cathodes. A series of carbon-coated Li2FeSiO4 samples were prepared through a hydrothermal and solid-state reaction route at a fixed sucrose content (14 wt% carbon) with varying amounts of sublimed sulfur at 5, 10, 15, 20 and 25 at%. The crystal structures, chemical compositions, microstructures and electrochemical performances of the differently sulfur-modified Li2FeSiO4/C were systematically investigated. The sulfur-carbon co-modifications and possible existing chemical states of sulfur are discussed in terms of the surface and near-bulk modifications. It was found that all the samples exhibited a monoclinic P21 structural Li2FeSiO4, while the sulfur contents over 10 at% formed impure phases such as iron sulfides (Fe1-xS) and lithium metasilicate (Li2SiO3). Furthermore, three types of sulfur states could be found when sulfur and carbon were added simultaneously into Li2FeSiO4. The surfaces were predominated by S–C and S–O–C, indicating the sulfur-carbon co-modification, which would reduce the resistance at the solid/electrode interface (SEI) but increase the charge transfer resistance. Near the bulk, the enhanced interactions between sulfur and iron S–Fe(−S) or sulfur and silicon S–Si(−O) may lead to the formation of possible impurities or oxygen substitution by sulfur. The former is detrimental as the effective sulfur amount is reduced, while the latter is beneficial to improve specific capacity and cycle stability. The overall performance of sulfur-carbon co-modified sample is influenced complicatedly by the sulfur content. The best initial discharge capacity of 152.3 mAh∙g-1 was obtained with 5 at% sulfur modification, while the best overall performance, showing a typical warm-up response and good cycle stability, was observed with 15 at% sulfur modification.

Features of obtaining an aseptic culture of Prunus dulcis (Mill.) D.A. Webb.

The purpose of the presented article is to establish the features of obtaining an aseptic culture of regenerants of Prunus dulcis in vitro. Since the impact of climate change is becoming increasingly large-scale in Ukraine, one of the urgent problems that hinders humanity, both in terms of agro-ecology and food, is the need to diversify traditional agriculture. Mydal is one of the valuable promising nut crops in Ukraine, thanks to which it is possible to diversify the climatic risks listed above. The varieties of domestic selection were taken for experiments, since foreign selection with low winter resistance and a long growing season are not suitable for our zone. Four intensive new varieties of almonds E5 Borozan, M41 Alex, Georgia, Louise, which were bred by breeder V.M. Babanskyi and entered into the State Register of Plant Varieties, and allowed in Ukraine for cultivation. One of the reliable methods of reproduction is microclonal reproduction, with the help of which it is possible to quickly obtain high-quality, disease-free planting material. Therefore, for the production of planting material, modern nurseries are switching to biotechnological methods. It was established that the preparation of explant donors reduces the number of primary explants that released phenolic substances. In addition to the preparation of donors, nutrients, which were present in different amounts in nutrient media with different composition, had a significant impact. The fewest explants with phenol-like exudate were on NAM and NRM media.Common to these two environments is a relatively low content of nitrogen in both ammonium and nitrate forms, and the DKW environment contains the highest amount of sulfur. The release of phenol-like exudate also depended on the biological characteristics of almond varieties. The highest number of primary explants was in the high-growing variety E5 Borozan, and the least in the variety Louise with medium growth intensity. Depending on the variety, 81–91 % were free from contaminants in the depository, while 59–70 % were in control. Morphogenic and at the same time without signs of contamination were found from 69 % among the explants of the Louise variety and up to 73 % of the E5 Borozan variety, compared to 35 and 51 %, respectively, in the control. Based on the results of the research, it was established that the influence of the time of isolation of the primary explants and the features of the interaction of the plant and its surrounding microbiota in different seasons are different. This is manifested in the features of contamination by these objects of primary explants and, accordingly, the success of decontamination (E1) and the appearance of microbiological contamination on the nutrient medium. Key words: microclonal propagation, nut crops, multiplication, morphogenesis, contaminants, decontamination.

STATUS AND FORMS OF SULPHUR IN SOILS OF WUDIL AND GAYA, KANO STATE, NIGERIA.

An investigation study was carried out to determine the status and forms of sulphur in soils of Wudil and Gaya, Kano state, Nigeria. Soils were collected using grid sampling method across two farming communities, Gaya and Wudil Local Government areas of Kano state. A total of 297 samples were collected at a depth of 0 - 30 cm. The samples were subjected to routine soil tests while the forms of sulphur were determined using turbidmetric method. Descriptive analysis was used for the interpretation of the data. The result obtained showed that soils from both locations were sandy loam with slightly acidic to neutral pH and low content of organic matter (0.38 and 0.24%) and nitrogen (0.06 and 0.04%). The sulphur level in both locations was sufficient. Differences in the concentration of the forms of sulphur were observed. Total sulphur had the highest amount of sulphur 498.30 mg kg-1, while non-sulphate sulphur had the least amount 0.74 mg kg-1. The low amounts of adsorbed and non-sulphate sulphur observed were attributed to the texture (sandy loam) and pH (6.24 and 6.99) of the soil. It can be concluded that the sulphur levels in both locations; Gaya and Wudil were high. Therefore, management strategies that will enable sulphur mineralization in the soil should be maintained by farmers to enhance availability of sulphate in the soil.

Assessment of Sulfur Impurities in GMP-Grade Diisopropylcarbodiimide and Their Impact on Coupling Reagent-Induced Side Reactions in Peptide Synthesis

Diisopropylcarbodiimide (DIC) constitutes one of the most widely used coupling reagents for amide bond formation in peptide synthesis. We have previously reported that DIC contains a varying amount of sulfur (61–2030 ppm), and that the main S-containing impurity in DIC is the thiourea DITU, which exhibits an excellent ability to suppress side reactions caused by N-oxyl radicals formed from common N-hydroxyl-coupling additives such as HOBt and Oxyma (Green Chem. 2019, 21, 5990). Aiming to understand how the quality of DIC impacts peptide synthesis, here, we report an evaluation of 14 batches of GMP-grade DIC from seven different vendors. With the evaluation by elemental analysis (S), gas chromatography–mass spectrometry, high-performance liquid chromatography, liquid chromatography-mass spectrometry, and nuclear magnetic resonance, we determined that the main S-containing impurity in DIC currently in use is not DITU, but rather the diazetidine-2-thione [1,3-diisopropyl-4-(isopropylimino)-1,3-diazetidine-2-thione, DIDT], formed by a 2 + 2 cycloaddition between DIC and iPr-NCS. The identity of DIDT was confirmed by a synthesis from DIC and iPr-NCS, followed by spiking a batch of DIC with the synthesized DIDT material. In a comparative evaluation of DITU and DIDT aimed at determining their ability to suppress breakdown of Fmoc-Cys(Trt)-OH caused by N-oxyl radicals formed from Oxyma, DITU completely prevented the Cys decomposition, whereas DIDT had no effect on the suppression of the breakdown of the amino acid. Finally, catalytic amounts of DITU as well as thiols DTT and NAC had a positive effect on minimization of the HOBt-induced breakdown of Fmoc-Trp(Boc)-OH, whereas the urea DIU, formed in every DIC-mediated peptide coupling reaction, accelerated the breakdown of the Trp substrate.

A review on the application of machine learning in production of woody biomass from natural and planted forests

The forest is considered as a significant source of woody biomass production. Sustainable production of wood, lower emittance of CO2 from burning, and lower amount of sulfur and heavy metals are the advantages of woods rather than fossil fuels. The utilization of biomass, as an energy resource, is required four main steps of production, pretreatment, bio-refinery, and upgrading. This work reviews Machine Learning applications in the production of the woody biomass raw material in forests because investigating numerous related works concluded that there is a considerable reviewing gap in analyzing and collecting the applications of Machine Learning in the woody biomass. To fill this gap in the current work, the origin of woods is explained and the application of Machine Learning in this section is scrutinized. Then, the multidisciplinary enhancement approaches in the production of plants as well as the role of Machine Learning in each of them are reviewed. Meanwhile, the role of natural and planted forests in the production of woody biomass is explained and the application of Machine Learning in these areas is surveyed. Summarily, after analysis of numerous papers, it is concluded that Machine Learning and Deep Learning is widely utilized in the production of woody biomass to enhance the wood production quantity and quality, improve the predictions, enhance the harvesting techniques, and diminish the losses.

Controlled and tunable growth of ambient stable 2D PtS2 thin film and its high-performance broadband photodetectors

PtS2, a group-10 transition metal dichalcogenide (TMDC), has recently attracted enormous interest owing to its tunable band gap (0.25–1.6 eV), high carrier mobility, and large current on-off ratio of the devices. In contrast to other TMDCs, the growth of PtS2 is more difficult, partly due to the nobility of Pt and partly due to the easier formation of the more stable PtS phase rather than PtS2. Herein, we investigate the effect of critical growth parameters like sulfur amount, Pt thickness and gas flow rate for the control and large area growth of PtS2 via thermal assisted conversion process in atmospheric chemical vapour deposition. The detailed characterization using Raman and X-ray photoelectron spectroscopy (XPS) suggests a controlled transition from PtS to PtS2, which can be obtained by fine tuning of these growth parameters. Furthermore, the optimized growth condition of PtS2 is highly reproducible and can be grown on varieties of substrates like SiO2/Si, sapphire, p-type Si, and even on flexible mica substrate. Finally, a high-performance PtS2 photodetector (PD) was fabricated on different substrates. The PD fabricated on SiO2/Si substrate with a detection range covering from visible to NIR region (400–1100 nm) showed a high responsivity and detectivity of 31.38 AW-1 and 3.92 × 1013 Jones, respectively, under 900 nm illumination at a low bias of 1 V. This work demonstrates an effective approach to control the growth of PtS2 on varieties of substrate for high-performance next-generation photodetector for NIR photodetection applications.