C2 C3 Research Articles

An Economic Analysis of Pigeon Pea Production in Maharashtra State, India

This study is based on "An economic analysis of pigeon pea production in districts of Maharashtra state”. The study was conducted in districts were highest area under pigeon pea cultivation in Maharashtra of India. The present study was based on primary data collected from 120 farmers in districts of Maharashtra, during the agricultural year 2021-22. The cost concepts approach to farm costing is widely used in India. To work out the cost of cultivation standard method of cost of cultivation employed by commission on Agricultural Costs and Price (CACP) Ministry of Agriculture (GOI). The directorate of economics and statistics, Government of India estimated different costs as (Cost A1, Cost A2, Cost B1, Cost B2, Cost C1, Cost C2, and Cost C3) The total cost of cultivation of pigeon pea came to ₹. 50548.17 per hectare in which the share of Cost-B2 was Rs.44708.43 (88.45 %) followed by Cost-A2 was ₹. 30053.85 (59.46 %). Per quintal average price of pigeon pea was ₹. 6198.58. Gross returns were ₹. 84345.37 in which main produce was of ₹.79465.90 and by produce ₹. 4919.02. The per hectare net profit from pigeon pea cultivation crop was gained ₹.33797.20. Hence, the cost benefit ratio was highest i.e. 1.67.

CO2 reduction employing MgH2 for CH4–H2 mixtures production through mechano-chemical processes

The CO2 methanation employing MgH2 as a source of hydrogen is investigated via mechano-chemical processes through ball milling at room temperature under different experimental conditions such as the presence/absence of catalyst, the milling duration, the molar ratio between the hydride and CO2 and the pre-milling of Ni–MgH2 mixture. The positive effect of Ni addition is demonstrated. After 5h of milling under CO2, the absence of catalyst causes the CH4 yield to drop from 70.0 to 59.0%, from 73.0 to 33.5% and from 54.0 to 40.1%, considering molar ratios of 4:1, 3:1 and 2:1, respectively. The pre-milling of nickel-catalyzed system or the addition of CNTs do not provide significant improvements. This investigation shows that similar methane yields to those obtained by thermo-chemical methods can be achieved, but involving shorter times (5 h versus 24 h) and lower temperatures (room temperature versus 400 °C). The ball collisions during milling allow overcoming passivation phenomena of MgH2 and Mg, promoting the methanation process but with lower selectivity as contamination with Fe from the milling jar provides a catalytic alternative route for the generation of C2–C3 hydrocarbons.

Rod Migration into the Posterior Cranial Fossa after C1–C2–C3–C4 Screw Fixation: Case Report and Review of the Literature

AbstractScrew loosening, avulsion, fracture, and rod migration are mechanical complications associated with dorsal fixation of the cervical spine. These usually occur in the late postoperative period and range from 2 to 5%. In this article, we describe a rare case of rod migration into the posterior cranial fossa 4 years after C1–C2–C3–C4 screw fixation in a patient with traumatic fracture of the C2 and C3 vertebrae.

Enantioselectivity in the enzymatic dehydration of malate and tartrate: Mirror image specificities of structurally similar dehydratases.

Malate (2-hydroxysuccinic acid) and tartrate (2,3-dihydroxysuccinic acid) are chiral substrates; the former existing in two enantiomeric forms (R and S) while the latter exists as three stereoisomers (R,R; S,S; and R,S). Dehydration by stereospecific hydrogen abstraction and antielimination of the hydroxyl group yield the achiral products fumarate and oxaloacetate, respectively. Class-I fumarate hydratase (FH) and L-tartrate dehydratase (L-TTD) are two highly conserved enzymes belonging to the iron-sulfur cluster hydrolyase family of enzymes that catalyze reactions on specific stereoisomers of malate and tartrate. FH from Methanocaldococcus jannaschii accepts only (S)-malate and (S,S)-tartrate as substrates while the structurally similar L-TTD from Escherichia coli accepts only (R)-malate and (R,R)-tartrate as substrates. Phylogenetic analysis reveals a common evolutionary origin of L-TTDs and two-subunit archaeal FHs suggesting a divergence during evolution that may have led to the switch in substrate stereospecificity preference. Due to the high conservation of their sequences, a molecular basis for switch in stereospecificity is not evident from analysis of crystal structures of FH and predicted structure of L-TTD. The switch in enantiomer preference may be rationalized by invoking conformational plasticity of the amino acids interacting with the substrate, together with substrate reorientation and conformer selection about the C2C3 bond of the dicarboxylic acid substrates. Although classical models of enzyme-substrate binding are insufficient to explain such a phenomenon, the enantiomer superposition model suggests that a minor reorientation in the active site residues could lead to the switch in substrate stereospecificity.

Rainwater extracting characteristics and its potential impact on DBPs generation: A case study

Frequent extreme precipitation events due to global warming can lead to large amounts of pollutants entering source water bodies via surface runoff and wet deposition, thus posing a threat to water supply security. In order to better understand the source characteristics and leaching mechanisms of rainwater dissolved organic matter (DOM), as well as its disinfection by-products formation potential (DBPsFP) during disinfection processes, rainwater samples were collected and extracting experiments were conducted. Three components were identified in rainwater through Parallel factor (PARAFAC) analysis, which were microbial humic-like component C1 (63.1 %), protein (tryptophan-like) component C2 (28.9 %), marine or terrestrial humic-like component C3 (8.1 %). The average molecular weight of rainwater fractions was ordered: hydrophobic neutral (HON) < hydrophobic bases (HOB) < hydrophobic acidic (HOA) < hydrophilic (HIS). The HOA and HON fractions of rainwater were the dominant precursors of trihalomethanes (THMs), while the rainwater HON fraction and hydrophilic fraction were the main precursor of haloacetic acids (HAAs) and trihloroacetonitrile (TCAN), respectively. Subsoil extracts had a higher concentration of dissolved organic carbon (DOC) and total dissolved nitrogen (TDN) than topsoil extracts. Partial least squares path modeling (PLS-PM) demonstrated that the extraction temperature was the dominant factor affecting the abundance of DOM in the topsoil extracts (R2 = 0.28), while the extraction time accounted more for the abundance of fluorescence substance and physicochemical indices in the subsoil extracts (R2 = 0.23 and 0.32, respectively). These results provide key information for controlling the impacts of global warming, in particular the risk of water sources being heavily contaminated by request rainfalls.

Effects of the potassium incorporation in Fe–Ce–Zr based catalysts and activation condition in CO2 hydrogenation to C2/C3 olefins at atmospheric pressure

Fe–Ce–Zr-based catalysts (FCZ) were promoted with potassium and evaluated in the CO2 hydrogenation reaction, carried out at atmospheric pressure, to produce light olefins, as ethene and propene. The FCZ catalyst was prepared using the coprecipitation technique, followed by a hydrothermal step. Potassium was added to the catalyst considering four nominal weight contents (0.5, 1, 2, and 4% wt) through wet impregnation. They were characterized using the following techniques: XRF, XRD, XPS, TPR-H2, TPD-H2, TPD-CO2, and in situ DRIFTS along the CO2 desorption and CO2 hydrogenation reaction. Selectivity towards ethene and propene reached the highest values with catalysts containing 1% and 2% wt of K. With this last one, the selectivity towards CO was around 95%, as potassium promotes the reverse water-gas shift reaction. Nonetheless, with this catalyst, the selectivity towards CH4, on a CO-free basis, was lower than 40%, and the olefins’ concentration in the C2–C3 range was superior to 90%, which can facilitate the light olefins separation in downstream processes. The catalysts were also in situ activated using the same feed flow, i.e., H2 and CO2 simultaneous flow, with the H2: CO2 ratio of 3:1, at 550 °C, for 1 h. CO2 conversion showed opposite trends for the case of H2 and H2+CO2 activation. With the former condition, the CO2 conversion increased with the incorporation of potassium, and it decreased for the second case. As the capability of the H2 adsorption diminished with the potassium incorporation to the catalysts, there was not enough hydrogen available to react with the CO2. Hence, for the activation using H2+CO2 flow, CO2 conversion diminished with potassium incorporation.

Insight into the pathways of biochar/smectite-induced humification during chicken manure composting

As representative organic and inorganic additives, both biochar and smectite exhibit an excellent capacity to improve humification efficiency during composting. Nevertheless, the mechanisms underlying biochar/smectite-induced compost humification have still not been fully explored from the perspective of overall organic substances. In this study, three composting treatments were performed as follows: 10 % biochar-amended composting, 10 % smectite-amended composting and natural composting without any additive. UV–visible parameters and synchronous hetero two-dimensional correlation spectra showed that biochar accelerated dissolved organic matter (DOM) complications, unsaturation and aromatization. For example, biochar promoted the C2 and simple C3 peaks to convert into a sophisticated C3/360 peak. However, the effect of smectite was negligible in complicating the DOM structure. Both biochar and smectite displayed an invigorating role in promoting humic substance (HS) formation. The strengthened relations between bacterial richness and physicochemical indicators and HS fractions might contribute to the positive action of biochar/smectite on HS synthesis. Network analysis showed that both bacterial functional omnipotence and specialization in response to the addition of catalysts may contribute to compost humification. The chemical pathway involved in DOM humification was intensified by enhancing the role of pH in biochar composting and weakening the degradation of unsaturated aromatic compounds of DOM with smectite addition. These findings benefit the practical application of biochar/smectite in promoting composting efficiency.

Active Sites Decorated Nonpolar Pore-Based MOF for One-step Acquisition of C2 H4 and Recovery of C3 H6.

Herein, a 2-fold interpenetrated metal-organic framework (MOF) Zn-BPZ-TATB with accessible N/O active sites in nonpolar pore surfaces was reported for one-step C2 H4 purification from C2 H6 or C3 H6 mixtures as well as recovery of C3 H6 from C2 H6 /C3 H6 /C2 H4 mixtures. The MOF exhibits the favorable C2 H6 and C3 H6 uptakes (>100 cm3 g-1 at 298 K under 100 kPa) as well as selective adsorption of C2 H6 and C3 H6 over C2 H4 . The C3 H6 - and C2 H6 -selective feature were investigated detailedly by experimental tests as well as sorption kinetic studyies. Molecular modelling revealed the multiple interactions between C3 H6 or C2 H6 molecules and methyl groups as well as triazine rings in pores. Zn-BPZ-TATB not only can directly generate 323.4 L kg-1 and 15.4 L kg-1 of high-purity (≥99.9 %) C2 H4 from C3 H6 /C2 H4 and C2 H6 /C2 H4 mixtures, but also provide a large high-purity (≥99.5 %) C3 H6 recovery capacity of 60.1 L kg-1 from C3 H6 /C2 H4 mixtures. More importantly, the high-purity C3 H6 (≥99.5 %) and C2 H4 (≥99.9 %) with the productivities of 38.2 and 12.7 L kg-1 can be simultaneously obtained from C2 H6 /C3 H6 /C2 H4 mixtures through a single adsorption/desorption cycle.

Effects of Concentrate Feeding Sequence on Growth Performance, Nutrient Digestibility, VFA Production, and Fecal Microbiota of Weaned Donkeys.

In this study, effects on the growth performance, nutrient digestibility, volatile fatty acids (VFA) production, and fecal microbiota of weaned donkeys were observed using different concentrate feeding sequences. Fifteen healthy 6-month-old weaned male donkeys with a body weight of 117.13 ± 10.60 kg were randomly divided into three treatment groups, including group C1 (roughage-then-concentrate), group C2 (concentrate-then-roughage), and group C3 (total mixed ration, TMR). The experiment lasted 35 d. We measured nutrient digestion by the acid-insoluble ash method and analyzed the fecal microbiota of the weaned donkeys by high-throughput sequencing of 16s rRNA genes in the V3-V4 region. The results show that group C3 obtained the best growth performance, and the digestibility of crude protein (CP) and crude extract (EE) was significantly higher than that of group C1 (p < 0.05). Acetic acid, isobutyric acid, valeric acid, isovaleric acid, and caproic acid were notably different among all groups (p < 0.05). In addition, we observed that Firmicutes and Bacteroidetes were dominant in the fecal microbes of each group, and Firmicutes was significantly higher in group C3 (p < 0.05). At the genus level, the different genera were Treponema, Rikenellaceae-RC9-gut-group, Unidentified-F082, and Bacteroidales-RF16-group (p < 0.05). The prediction of fecal microbiota function by PICRUSt indicated that different feeding sequences had minimal impact on the function of the fecal microbiota, particularly on the high-abundance pathway. In summary, the concentrate feeding sequence changed the composition of the fecal microbe of weaned donkeys.

Establishment of an animal model of adjacent segment degeneration after interbody fusion and related experimental studies

BackgroundDegenerative spine conditions are common and frequent clinical diseases, and adjacent segment disease (ASD) after spinal fusion (SF) is a common complication after spinal fusion (SF). In this study, we established an animal model of ASD after interbody fusion to observe the morphologic changes of adjacent segment (AS) disks and to determine the expression and significance of tumor necrosis factor-alpha (TNF-α) and interleukin-1beta (IL-1β) in ASD tissues to provide a good experimental basis and reference for clinical prevention and treatment of ASD after interbody fusion.MethodsThirty-six male and female New Zealand rabbits weighing 2.0–2.5 kg were randomly divided into control group (group A) and experimental groups (groups B, C, and D), with 9 rabbits in each group, of which groups B, C, and D were the 4-, 8-, and 12-week groups, respectively. Autologous iliac bone grafts were used as the bone graft material. In the experimental groups, a SF was performed on the C2–C3 intervertebral space. The C3–4 adjacent segments were examined. In the experimental group, the animals were subjected to gross observation, X-ray examination, hand touch inspection, and micro-computed tomography (micro-CT) 4, 8, and 12 weeks after surgery. The micromorphologic changes of the cervical disks in the segments of the control group and experimental groups were observed under light microscopy. Immunohistochemistry and Western blotting were used to detect the expression of TNF-α and IL-1β in the AS tissues after interbody fusion in the control and experimental groups.ResultsThe measurement data of the rabbit cervical spine bony structures indicated that the length of the vertebral body and the sagittal diameter of the lower end of the vertebral body decreased gradually from the 2nd–6th cervical vertebrae, and the difference was statistically significant (P < 0.05). The difference in the transverse diameter of the lower end of the vertebral body was not statistically significant (P > 0.05), the change in the oblique diameter of the lower end of the vertebral body fluctuated, and the difference was statistically significant (P < 0.05). The fusion rate of the cervical spine by hand touch inspection was 22.2% (2/9), 55.6% (5/9), and 88.9% (8/9) in groups B, C, and D, respectively. The differences in bone volume-to-total volume (BV/TV) and X-ray scores were statistically significant in groups B, C, and D (P < 0.05). Significant degeneration occurred in groups B, C, and D compared with group A. The expression of TNF-α and IL-1β in the intervertebral disk tissue was significantly higher in groups B, C, and D compared with group A (P < 0.05), and increased with time.ConclusionIn this study, an animal model of ASD after interbody fusion fixation in rabbits was successfully established. Postoperative imaging and hand touch inspection showed a positive correlation between the amount of new intervertebral bone and the degree of fusion with time. The results of immunohistochemistry and Western blot showed that TNF-α and IL-1β were highly expressed in the AS tissues of the experimental group after interbody fusion, and the degree of disk degeneration was positively correlated with the time after interbody fusion.

Atypical extravertebral ventral cervical disc extrusion in a dog

AbstractA 6‐year‐old cocker spaniel dog was investigated by computed tomography for a marked neck pain more evident on ventroflexion. Cervical disc extrusion of mineralised nucleus pulposus material was identified in the vertebral canal dorsally to the C4–C5 intervertebral space, with spinal cord compression. Another mineralised material was also identified at an unusual location, ventrally to the C2–C3 intervertebral space. Ventral slot at C4–C5 intervertebral disc allowed surgical removal of the compressive disc, and longus colli muscles dissection at C2–C3 level allowed removal of the identified material, confirmed histologically as degenerated (mineralised) nucleus pulposus. Ventral paravertebral disc extrusion of degenerated nucleus pulposus extrusion is rarely described in human medicine. This case report illustrates the anatomical and imaging key points that support the diagnostic approach to a previously undescribed presentation of disc extrusion in dog.

Emergency Stenting of Tandem Stenoses of the Internal Carotid Artery Using Proximal Protection Against Distal Embolism “MoMa”

Man, 61 years old. Admitted with complaints of severe weakness in the right limbs, which developed about 4 hours ago. Multispiral computed tomography with cerebral angiography: signs of ischemic stroke in the basin of the left middle cerebral artery. Angiography of the brachiocephalic arteries (BCA) was performed: angiographic signs of damage to the BCA: the left internal carotid artery (ICA) of the C2–C3 segments up to subocclusion, up to 75% in the mouth and right third. The circle of Willis is closed.A multidisciplinary council made a decision on emergency stenting of tandem ICA stenoses using proximal protection against distal embolism “MoMa”. The course of the operation: after angiography, the sheath introducer was replaced by a guidewire sheath with a 9F introducer. A proximal protection system “MoMa” was installed along the diagnostic conductor 260 cm at the mouth of the left external carotid artery (ECA) and the middle third of the left common carotid artery (OCA). Baloons in the ECA and OCA were inflated. The Promus element 4.0x12 mm (DES) ICA was brought into the affected area of C2–C3 segments, positioned and opened at a pressure of up to 14 atm. The balloon catheter has been removed. Aspiration from the ICA. On check angiography, residual stenosis of the ICA stenting zone was 0%. On the test angiography intracranial arteries without signs of embolism. A Protege (7x10x40) mm stent was placed, positioned and deployed in the affected area of the orifice and the right third of the ICA. The delivery system has been removed. Aspiration from the ICA. On the test angiography, the residual stenosis of the ICA stenting zone was up to 0%. The distal embolism protection system has been removed. On the control angiography intracranial arteries without signs of embolism.The postoperative period was uneventful. On the 10th day after stenting, the neurological deficit regressed completely, the patient was discharged for outpatient observation in a satisfactory condition.CONCLUSIONS When performing brain revascularization in the most acute period of ischemic stroke, it is necessary to take into account the recommendations of multicenter studies that report such conditions for a successful outcome of the operation as: the diameter of the ischemic focus in the brain, not exceeding 2.5 cm and the absence of severe neurological deficit (more than the Rankin scale score 2). Within the framework of this clinical example, these recommendations were taken into account, which, among other things, contributed to the optimal outcome of urgent revascularization. Emergency stenting of tandem stenosis of the internal carotid artery using the device for proximal protection “MoMa” is effective in the presence of a closed structure of the circle of Willis. The technical complexity of the operation is associated with the installation of a catheter guide and its diameter of 9 Fr (catheters up to 7 Fr are usually used), which requires additional manual skills.

Impact of C3 laminectomy on cervical sagittal alignment in cervical laminoplasty: a prospective, randomized controlled trial comparing clinical and radiological outcomes between C3 laminectomy with C4–C6 laminoplasty and C3–C6 laminoplasty

Background ContextC3 laminectomy in cervical laminoplasty is a modified laminoplasty technique that can preserve the semispinalis cervicis muscle attached to the C2 spinous process. Several previous studies have shown that this technique can lead to better outcomes of postoperative axial neck pain and C2–C3 range of motion (ROM) than conventional cervical laminoplasty. However, there is still a lack of understanding of total and proportional postoperative cervical sagittal alignment outcomes. PurposeTo assess the effects of C3 laminectomy in cervical laminoplasty on postoperative cervical alignment and clinical outcomes. DesignA single-center, patient-blinded, randomized controlled trial. Patient SampleWe included consecutive 126 patients diagnosed with cervical spondylotic myelopathy (CSM) or ossification of posterior longitudinal ligament (OPLL) who were scheduled for cervical laminoplasty from March 2017 to January 2020. Outcome MeasuresThe primary outcome measures were C2–C7 Cobb angle (CA) and neck disability index (NDI). Secondary outcomes measures included other clinical outcomes and radiographic parameters including segmental Cobb angle and presence of C2–C3 interlaminar fusion. MethodsPatients were randomly allocated to either the C3 laminectomy with C4–C6 laminoplasty group (LN group) or the C3–C6 laminoplasty group (LP group) at a 1:1 ratio. Laminoplasty was performed using a unilateral open-door technique and stabilized with titanium mini plates. A linear mixed model analysis was employed to examine the longitudinal data from postoperative 1-year through 3-year. Additional analysis between three types of cervical sagittal alignment morphology was done. ResultsAmong 122 patients who were randomly allocated to one of two groups (LN group, n=61; LP group, n=61), modified intent-to-treat analysis was done for 109 patients (LN group, n=51, LP group, n=58) who had available at least a year of postoperative data. Postoperative C2–C7 CA was not significantly different between the two groups. However, NDI was significantly different between the two groups (12.8±1.0 in the LN group vs 8.6±1.0 in LP group, p=.005), which exceeded the minimum clinically important difference (MCID). The postoperative C2–C3 CA was significantly greater in the LN group (7.1±0.5° in LN group vs 3.2±0.5° in LP group, p<.001) while C4–C7 CA was significantly smaller in the LN group (3.9±0.8° in LN group vs 7.7±0.7° in LP group, p<.001) with greater cSVA in the LN group (31.6±1.4 mm in LN group vs 25.5±1.3 mm in LP group at postoperative 3-year, p=.002). Postoperative Euro-Quality of Life-5 Dimension (EQ-5D), numerical rating scores for neck pain (NRS-N) were significantly better in the LP group than in the LN group (all p<.05) and only EQ-5D surpassed the MCID. The C2-C3 fusion rate was significantly different between the LN group (9.8%) and the LP group (44.8%) (p<.001). The LN group showed a higher prevalence of a specific cervical alignment morphology characterized by a sigmoid shape with proximal lordosis and distal kyphosis (S curve). This S curve demonstrated significantly unfavorable outcomes across multiple outcome variables. ConclusionThe impact of C3 laminectomy in cervical laminoplasty on postoperative kyphosis among patients with CSM or OPLL did not significantly differ from that of C3–C6 laminoplasty. However, C3 laminectomy in cervical laminoplasty might result in an unfavorable clinical outcome with an unbalanced cervical sagittal alignment characterized by a sigmoid shape with proximal lordosis and distal kyphosis.

Carbon dioxide gasification characteristics of disposable COVID-19 masks using bubbling fluidized bed reactor

The global demand for masks has increased significantly owing to COVID-19 and mutated viruses, resulting in a massive amount of mask waste of approximately 490,000 tons per month. Mask waste recycling is challenging because of the composition of multicomponent polymers and iron, which puts them at risk of viral infection. Conventional treatment methods also cause environmental pollution. Gasification is an effective method for processing multicomponent plastics and obtaining syngas for various applications. This study investigated the carbon dioxide gasification and tar removal characteristics of an activated carbon bed using a 1-kg/h laboratory-scale bubble fluidized bed gasifier. The syngas composition was analyzed as 10.52 vol% of hydrogen, 6.18 vol% of carbon monoxide, 12.05 vol% of methane, and 14.44 vol% of hydrocarbons (C2–C3). The results of carbon dioxide gasification with activated carbon showed a tar-reduction efficiency of 49%, carbon conversion efficiency of 45.16%, and cold gas efficiency of 88.92%. This study provides basic data on mask waste carbon dioxide gasification using greenhouse gases as useful product gases.

Electrolessly Deposited Carbon-Supported CuNiSn Electrocatalysts for the Electrochemical Reduction of CO2

Aiming at developing low-cost, high-performance catalysts for the electrochemical reduction of CO2 (CO2-ERR) to valuable multicarbon (C2–C3) chemicals to alleviate global warming, trimetallic alloy electrocatalysts containing Cu, Ni, and Sn supported on a Pd-activated carbon fabric substrate (CS) were prepared via an electroless deposition method. The as-deposited CuNiSn/CS electrocatalysts were employed in CO2-ERR in an H-cell type reactor at an applied potential of −1.6 V vs. Ag/AgCl. The effect of the electroless deposition time (15, 30, and 45 min) was investigated, finding no significant structural differences according to the X-ray diffraction patterns. The evaluation of the reaction performance via linear sweep voltammetry revealed that CO2 was more effectively reduced to adsorbed species on the catalytic surface sites of the electrocatalyst prepared with a 30 min deposition time. The analysis of the gas and liquid products via gas chromatography and nuclear magnetic resonance, respectively, revealed that the Faradaic efficiency and H2 production over CuNiSn/CS was lower than those over related bimetallic and monometallic electrocatalysts, indicating the inhibition of the competitive H2 evolution reaction. Liquid products including formate, ethylene glycol, acetone, ethanol, acetate, and 1-buthanol were detected.

Effect of CNT over structural properties of SAPO-34 in MTO process: Experimental and molecular simulation studies

The hierarchical silicoaluminophosphate (SAPO-34) catalyst was synthesized using the mixtures of diethylamine (D) and butylamine (B) as a structure-directing agent (SDA), and carbon nanotube (CNT) as a secondary template in the hydrothermal method. The catalysts were characterized by Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), N2 physisorption, and temperature-programmed desorption of ammonia (NH3-TPD) techniques and evaluated for the catalytic activity in the Methanol to Olefins (MTO) process. The results showed that the use of CNT as the secondary template improved the hierarchical structure of SAPO-34 due to increasing the external surface area and mesoporosity and decreasing the particle size and as a result, made better the performance of the prepared SAPO-34 zeolite in the MTO process. Among all the prepared samples, the CNT-B-D catalyst synthesized by mixing three templates displayed the highest ethylene and propylene selectivity of 49% and 34%, respectively. Also, using CNT in the synthesis of samples increased the catalytic stability. In addition, pure, binary, and ternary adsorption isotherms and diffusivities of the main products and reactants over the SAPO-34 were investigated by theoretical measurements, because sorption and diffusion affect the catalyst stability and C2–C3 selectivity in the MTO reaction. The higher diffusion rate of ethylene leads to following the aromatic-based cycle in the MTO process.

Selective control of donor-acceptor Stenhouse adduct populations with non-selective stimuli

Selective control of donor-acceptor Stenhouse adduct populations with non-selective stimuli

Impact of different ventilation conditions on tobacco smoke-associated particulate matter emissions in a car cabin using the TAPaC platform

Despite antagonizing attempts from the tobacco industry, passive inhalation of tobacco smoke is known to be cancerogenic and toxic to human health for decades. Nonetheless, millions of non-smoking adults and children are still victims of second-hand smoke. Accumulation of particulate matter (PM) in confined spaces such as the car are particularly harmful due to high concentrations. We here aimed to analyze the specific effects of ventilation conditions in the setting of a car. By the use of the measuring platform TAPaC (tobacco-associated particulate matter emissions inside a car cabin), 3R4F reference cigarettes, Marlboro red, and Marlboro gold were smoked in a car interior with a volume of 3.709 m3. Seven different ventilation conditions (C1–C7) were analyzed. Under C1, all windows were closed. Under C2–C7, the car ventilation was turned on power level 2/4 with the air directed towards the windshield. Only the passenger side window was opened, where an outer placed fan could create an airstream speed of 15.9–17.4 km/h at one meter distance to simulate a driving car. C2: Window 10 cm opened. C3: Window 10 cm opened with the fan turned on. C4: Window half-opened. C5: Window half-opened with the fan turned on. C6: Window fully opened. C7: Window fully opened with the fan turned on. Cigarettes were remotely smoked by an automatic environmental tobacco smoke emitter and a cigarette smoking device. Depending on the ventilation condition the cigarettes emitted different mean PM concentrations after 10 min under condition C1 (PM10: 1272–1697 µg/m3, PM2.5: 1253–1659 µg/m3, PM1: 964–1263 µg/m3) under C2, C4, and C6 (PM10: 68.7–196.2 µg/m3, PM2.5: 68.2–194.7 µg/m3, PM1: 66.1–183.8 µg/m3) C3, C5, and C7 (PM10: 73.7–139 µg/m3, PM2.5: 72–137.9 µg/m3, PM1:68.9–131.9 µg/m3). Vehicle ventilation is insufficient to protect passengers from toxic second-hand smoke completely. Brand-specific variations of tobacco ingredients and mixtures markedly influence PM emissions under ventilation conditions. The most efficient ventilation mode to reduce PM exposure was achieved by opening the passenger´s window 10 cm and turning the onboard ventilation on power level 2/4. In-vehicle smoking should be banned to preserve innocent risk groups (e.g., children) from harm.

Direct C–C bond scission of xylitol to ethylene and propylene glycol precursors using single-atom catalysts (SACs) anchored on MgO

Shorter chain alcohols, as opposed to longer ones, are beneficial as biomass feedstock for chemicals and fuels, including hydrogen production. More so, it has been demonstrated that carbon–carbon rather than carbon–oxygen bond-cleaving activity determines the product selectivity of a metal catalyst for higher oxygenates reforming. In this report, we investigate the direct C2–C3 bond-cleaving activity of xylitol via first-principles, periodic density functional theory calculations to identify the differences in activities between single-crystal catalysts (SCCs) and single-atom catalysts (SACs). A comparison of the kinetic barriers revealed that xylitol's C–C bond scission appears to be a near-impossible task on SCCs. However, SACs demonstrated higher performance. For example, Ir1/MgO and Ir1/MgO_Ovac (having surface oxygen vacancy) yielded ∼72% and 54% decrease, respectively, in Gibb’s free activation energy compared to Ir (111) at the xylitol reforming operating temperature of 473 K. Furthermore, electronic structure calculations revealed an up-shift in the DOS for the surface M1 atoms in all investigated SACs compared to the surface atoms of their respective SCCs, resulting in M1 higher d-band center and stronger adsorbate (s) binding. This study highlights the importance of SACs for boosting the atom efficiency of costly metals while also offering a new strategy for tuning the activity of catalytic reactions.

Poly(1-trimethylsilyl-1-propyne) of a &lt;i&gt;cis&lt;/i&gt;-Rich Configuration — a Membrane Material for the Separation of Butane/Methane Mixtures as Natural Gas Components

In this work, for the first time, we studied the permeability of individual lower hydrocarbons and in a C1/C4 mixture for films based on PTMSP of a new cis-enriched configurational composition (the content of cis-units in the samples was 80 and 90%). The methane permeability of freshly prepared cis-regular PTMSP films (90% of cis-units) exposed to air for a month is higher than the corresponding values of PTMSP films with 80% cis-units. The X-ray diffraction data indicate a looser packing of the cis-regular PTMSP. The introduction of the antioxidant Irganox 1076 into PTMSP films leads to a decrease in the initial level of the methane flux. At the same time, the permeability of films with the addition of Irganox 1076 over time (within 1 month) decreases much more slowly compared to films without the addition of an antioxidant. The permeability of individual lower hydrocarbons through PTMSP films without and with the addition of Irganox 1076 increases in the order С1 C2 C3 C4. The value of the separation factor in the n-butane/methane mixture reaches 33, which is almost 7 times higher than the selectivity for individual components. The high level of n‑butane permeability of cis-enriched PTMSP is maintained for at least a month of films storage in air.